drivers/md/raid5.c

   1 /*
   2  * raid5.c : Multiple Devices driver for Linux
   3  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   4  *         Copyright (C) 1999, 2000 Ingo Molnar
   5  *         Copyright (C) 2002, 2003 H. Peter Anvin
   6  *
   7  * RAID-4/5/6 management functions.
   8  * Thanks to Penguin Computing for making the RAID-6 development possible
   9  * by donating a test server!
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2, or (at your option)
  14  * any later version.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * (for example /usr/src/linux/COPYING); if not, write to the Free
  18  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 /*
  22  * BITMAP UNPLUGGING:
  23  *
  24  * The sequencing for updating the bitmap reliably is a little
  25  * subtle (and I got it wrong the first time) so it deserves some
  26  * explanation.
  27  *
  28  * We group bitmap updates into batches.  Each batch has a number.
  29  * We may write out several batches at once, but that isn't very important.
  30  * conf->seq_write is the number of the last batch successfully written.
  31  * conf->seq_flush is the number of the last batch that was closed to
  32  *    new additions.
  33  * When we discover that we will need to write to any block in a stripe
  34  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  35  * the number of the batch it will be in. This is seq_flush+1.
  36  * When we are ready to do a write, if that batch hasn't been written yet,
  37  *   we plug the array and queue the stripe for later.
  38  * When an unplug happens, we increment bm_flush, thus closing the current
  39  *   batch.
  40  * When we notice that bm_flush > bm_write, we write out all pending updates
  41  * to the bitmap, and advance bm_write to where bm_flush was.
  42  * This may occasionally write a bit out twice, but is sure never to
  43  * miss any bits.
  44  */
  45
  46 #include <linux/blkdev.h>
  47 #include <linux/kthread.h>
  48 #include <linux/raid/pq.h>
  49 #include <linux/async_tx.h>
  50 #include <linux/module.h>
  51 #include <linux/async.h>
  52 #include <linux/seq_file.h>
  53 #include <linux/cpu.h>
  54 #include <linux/slab.h>
  55 #include <linux/ratelimit.h>
  56 #include <linux/nodemask.h>
  57 #include <linux/flex_array.h>
  58 #include <linux/sched/signal.h>
  59
  60 #include <trace/events/block.h>
  61 #include <linux/list_sort.h>
  62
  63 #include "md.h"
  64 #include "raid5.h"
  65 #include "raid0.h"
  66 #include "bitmap.h"
  67 #include "raid5-log.h"
  68
  69 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  70
  71 #define cpu_to_group(cpu) cpu_to_node(cpu)
  72 #define ANY_GROUP NUMA_NO_NODE
  73
  74 static bool devices_handle_discard_safely = false;
  75 module_param(devices_handle_discard_safely, bool, 0644);
  76 MODULE_PARM_DESC(devices_handle_discard_safely,
  77                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  78 static struct workqueue_struct *raid5_wq;
  79
  80 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  81 {
  82         int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
  83         return &conf->stripe_hashtbl[hash];
  84 }
  85
  86 static inline int stripe_hash_locks_hash(sector_t sect)
  87 {
  88         return (sect >> STRIPE_SHIFT) & STRIPE_HASH_LOCKS_MASK;
  89 }
  90
  91 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  92 {
  93         spin_lock_irq(conf->hash_locks + hash);
  94         spin_lock(&conf->device_lock);
  95 }
  96
  97 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  98 {
  99         spin_unlock(&conf->device_lock);
 100         spin_unlock_irq(conf->hash_locks + hash);
 101 }
 102
 103 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
 104 {
 105         int i;
 106         spin_lock_irq(conf->hash_locks);
 107         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 108                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 109         spin_lock(&conf->device_lock);
 110 }
 111
 112 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 113 {
 114         int i;
 115         spin_unlock(&conf->device_lock);
 116         for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 117                 spin_unlock(conf->hash_locks + i);
 118         spin_unlock_irq(conf->hash_locks);
 119 }
 120
 121 /* Find first data disk in a raid6 stripe */
 122 static inline int raid6_d0(struct stripe_head *sh)
 123 {
 124         if (sh->ddf_layout)
 125                 /* ddf always start from first device */
 126                 return 0;
 127         /* md starts just after Q block */
 128         if (sh->qd_idx == sh->disks - 1)
 129                 return 0;
 130         else
 131                 return sh->qd_idx + 1;
 132 }
 133 static inline int raid6_next_disk(int disk, int raid_disks)
 134 {
 135         disk++;
 136         return (disk < raid_disks) ? disk : 0;
 137 }
 138
 139 /* When walking through the disks in a raid5, starting at raid6_d0,
 140  * We need to map each disk to a 'slot', where the data disks are slot
 141  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 142  * is raid_disks-1.  This help does that mapping.
 143  */
 144 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 145                              int *count, int syndrome_disks)
 146 {
 147         int slot = *count;
 148
 149         if (sh->ddf_layout)
 150                 (*count)++;
 151         if (idx == sh->pd_idx)
 152                 return syndrome_disks;
 153         if (idx == sh->qd_idx)
 154                 return syndrome_disks + 1;
 155         if (!sh->ddf_layout)
 156                 (*count)++;
 157         return slot;
 158 }
 159
 160 static void print_raid5_conf (struct r5conf *conf);
 161
 162 static int stripe_operations_active(struct stripe_head *sh)
 163 {
 164         return sh->check_state || sh->reconstruct_state ||
 165                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 166                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 167 }
 168
 169 static bool stripe_is_lowprio(struct stripe_head *sh)
 170 {
 171         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 172                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 173                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 174 }
 175
 176 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 177 {
 178         struct r5conf *conf = sh->raid_conf;
 179         struct r5worker_group *group;
 180         int thread_cnt;
 181         int i, cpu = sh->cpu;
 182
 183         if (!cpu_online(cpu)) {
 184                 cpu = cpumask_any(cpu_online_mask);
 185                 sh->cpu = cpu;
 186         }
 187
 188         if (list_empty(&sh->lru)) {
 189                 struct r5worker_group *group;
 190                 group = conf->worker_groups + cpu_to_group(cpu);
 191                 if (stripe_is_lowprio(sh))
 192                         list_add_tail(&sh->lru, &group->loprio_list);
 193                 else
 194                         list_add_tail(&sh->lru, &group->handle_list);
 195                 group->stripes_cnt++;
 196                 sh->group = group;
 197         }
 198
 199         if (conf->worker_cnt_per_group == 0) {
 200                 md_wakeup_thread(conf->mddev->thread);
 201                 return;
 202         }
 203
 204         group = conf->worker_groups + cpu_to_group(sh->cpu);
 205
 206         group->workers[0].working = true;
 207         /* at least one worker should run to avoid race */
 208         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 209
 210         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 211         /* wakeup more workers */
 212         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 213                 if (group->workers[i].working == false) {
 214                         group->workers[i].working = true;
 215                         queue_work_on(sh->cpu, raid5_wq,
 216                                       &group->workers[i].work);
 217                         thread_cnt--;
 218                 }
 219         }
 220 }
 221
 222 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 223                               struct list_head *temp_inactive_list)
 224 {
 225         int i;
 226         int injournal = 0;      /* number of date pages with R5_InJournal */
 227
 228         BUG_ON(!list_empty(&sh->lru));
 229         BUG_ON(atomic_read(&conf->active_stripes)==0);
 230
 231         if (r5c_is_writeback(conf->log))
 232                 for (i = sh->disks; i--; )
 233                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 234                                 injournal++;
 235         /*
 236          * In the following cases, the stripe cannot be released to cached
 237          * lists. Therefore, we make the stripe write out and set
 238          * STRIPE_HANDLE:
 239          *   1. when quiesce in r5c write back;
 240          *   2. when resync is requested fot the stripe.
 241          */
 242         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 243             (conf->quiesce && r5c_is_writeback(conf->log) &&
 244              !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 245                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 246                         r5c_make_stripe_write_out(sh);
 247                 set_bit(STRIPE_HANDLE, &sh->state);
 248         }
 249
 250         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 251                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 252                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 253                         list_add_tail(&sh->lru, &conf->delayed_list);
 254                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 255                            sh->bm_seq - conf->seq_write > 0)
 256                         list_add_tail(&sh->lru, &conf->bitmap_list);
 257                 else {
 258                         clear_bit(STRIPE_DELAYED, &sh->state);
 259                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 260                         if (conf->worker_cnt_per_group == 0) {
 261                                 if (stripe_is_lowprio(sh))
 262                                         list_add_tail(&sh->lru,
 263                                                         &conf->loprio_list);
 264                                 else
 265                                         list_add_tail(&sh->lru,
 266                                                         &conf->handle_list);
 267                         } else {
 268                                 raid5_wakeup_stripe_thread(sh);
 269                                 return;
 270                         }
 271                 }
 272                 md_wakeup_thread(conf->mddev->thread);
 273         } else {
 274                 BUG_ON(stripe_operations_active(sh));
 275                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 276                         if (atomic_dec_return(&conf->preread_active_stripes)
 277                             < IO_THRESHOLD)
 278                                 md_wakeup_thread(conf->mddev->thread);
 279                 atomic_dec(&conf->active_stripes);
 280                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 281                         if (!r5c_is_writeback(conf->log))
 282                                 list_add_tail(&sh->lru, temp_inactive_list);
 283                         else {
 284                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 285                                 if (injournal == 0)
 286                                         list_add_tail(&sh->lru, temp_inactive_list);
 287                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 288                                         /* full stripe */
 289                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 290                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 291                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 292                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 293                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 294                                         r5c_check_cached_full_stripe(conf);
 295                                 } else
 296                                         /*
 297                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 298                                          * r5c_try_caching_write(). No need to
 299                                          * set it again.
 300                                          */
 301                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 302                         }
 303                 }
 304         }
 305 }
 306
 307 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 308                              struct list_head *temp_inactive_list)
 309 {
 310         if (atomic_dec_and_test(&sh->count))
 311                 do_release_stripe(conf, sh, temp_inactive_list);
 312 }
 313
 314 /*
 315  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 316  *
 317  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 318  * given time. Adding stripes only takes device lock, while deleting stripes
 319  * only takes hash lock.
 320  */
 321 static void release_inactive_stripe_list(struct r5conf *conf,
 322                                          struct list_head *temp_inactive_list,
 323                                          int hash)
 324 {
 325         int size;
 326         bool do_wakeup = false;
 327         unsigned long flags;
 328
 329         if (hash == NR_STRIPE_HASH_LOCKS) {
 330                 size = NR_STRIPE_HASH_LOCKS;
 331                 hash = NR_STRIPE_HASH_LOCKS - 1;
 332         } else
 333                 size = 1;
 334         while (size) {
 335                 struct list_head *list = &temp_inactive_list[size - 1];
 336
 337                 /*
 338                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 339                  * remove stripes from the list
 340                  */
 341                 if (!list_empty_careful(list)) {
 342                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 343                         if (list_empty(conf->inactive_list + hash) &&
 344                             !list_empty(list))
 345                                 atomic_dec(&conf->empty_inactive_list_nr);
 346                         list_splice_tail_init(list, conf->inactive_list + hash);
 347                         do_wakeup = true;
 348                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 349                 }
 350                 size--;
 351                 hash--;
 352         }
 353
 354         if (do_wakeup) {
 355                 wake_up(&conf->wait_for_stripe);
 356                 if (atomic_read(&conf->active_stripes) == 0)
 357                         wake_up(&conf->wait_for_quiescent);
 358                 if (conf->retry_read_aligned)
 359                         md_wakeup_thread(conf->mddev->thread);
 360         }
 361 }
 362
 363 /* should hold conf->device_lock already */
 364 static int release_stripe_list(struct r5conf *conf,
 365                                struct list_head *temp_inactive_list)
 366 {
 367         struct stripe_head *sh, *t;
 368         int count = 0;
 369         struct llist_node *head;
 370
 371         head = llist_del_all(&conf->released_stripes);
 372         head = llist_reverse_order(head);
 373         llist_for_each_entry_safe(sh, t, head, release_list) {
 374                 int hash;
 375
 376                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 377                 smp_mb();
 378                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 379                 /*
 380                  * Don't worry the bit is set here, because if the bit is set
 381                  * again, the count is always > 1. This is true for
 382                  * STRIPE_ON_UNPLUG_LIST bit too.
 383                  */
 384                 hash = sh->hash_lock_index;
 385                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 386                 count++;
 387         }
 388
 389         return count;
 390 }
 391
 392 void raid5_release_stripe(struct stripe_head *sh)
 393 {
 394         struct r5conf *conf = sh->raid_conf;
 395         unsigned long flags;
 396         struct list_head list;
 397         int hash;
 398         bool wakeup;
 399
 400         /* Avoid release_list until the last reference.
 401          */
 402         if (atomic_add_unless(&sh->count, -1, 1))
 403                 return;
 404
 405         if (unlikely(!conf->mddev->thread) ||
 406                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 407                 goto slow_path;
 408         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 409         if (wakeup)
 410                 md_wakeup_thread(conf->mddev->thread);
 411         return;
 412 slow_path:
 413         local_irq_save(flags);
 414         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 415         if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
 416                 INIT_LIST_HEAD(&list);
 417                 hash = sh->hash_lock_index;
 418                 do_release_stripe(conf, sh, &list);
 419                 spin_unlock(&conf->device_lock);
 420                 release_inactive_stripe_list(conf, &list, hash);
 421         }
 422         local_irq_restore(flags);
 423 }
 424
 425 static inline void remove_hash(struct stripe_head *sh)
 426 {
 427         pr_debug("remove_hash(), stripe %llu\n",
 428                 (unsigned long long)sh->sector);
 429
 430         hlist_del_init(&sh->hash);
 431 }
 432
 433 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 434 {
 435         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 436
 437         pr_debug("insert_hash(), stripe %llu\n",
 438                 (unsigned long long)sh->sector);
 439
 440         hlist_add_head(&sh->hash, hp);
 441 }
 442
 443 /* find an idle stripe, make sure it is unhashed, and return it. */
 444 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 445 {
 446         struct stripe_head *sh = NULL;
 447         struct list_head *first;
 448
 449         if (list_empty(conf->inactive_list + hash))
 450                 goto out;
 451         first = (conf->inactive_list + hash)->next;
 452         sh = list_entry(first, struct stripe_head, lru);
 453         list_del_init(first);
 454         remove_hash(sh);
 455         atomic_inc(&conf->active_stripes);
 456         BUG_ON(hash != sh->hash_lock_index);
 457         if (list_empty(conf->inactive_list + hash))
 458                 atomic_inc(&conf->empty_inactive_list_nr);
 459 out:
 460         return sh;
 461 }
 462
 463 static void shrink_buffers(struct stripe_head *sh)
 464 {
 465         struct page *p;
 466         int i;
 467         int num = sh->raid_conf->pool_size;
 468
 469         for (i = 0; i < num ; i++) {
 470                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 471                 p = sh->dev[i].page;
 472                 if (!p)
 473                         continue;
 474                 sh->dev[i].page = NULL;
 475                 put_page(p);
 476         }
 477 }
 478
 479 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 480 {
 481         int i;
 482         int num = sh->raid_conf->pool_size;
 483
 484         for (i = 0; i < num; i++) {
 485                 struct page *page;
 486
 487                 if (!(page = alloc_page(gfp))) {
 488                         return 1;
 489                 }
 490                 sh->dev[i].page = page;
 491                 sh->dev[i].orig_page = page;
 492         }
 493
 494         return 0;
 495 }
 496
 497 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 498                             struct stripe_head *sh);
 499
 500 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 501 {
 502         struct r5conf *conf = sh->raid_conf;
 503         int i, seq;
 504
 505         BUG_ON(atomic_read(&sh->count) != 0);
 506         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 507         BUG_ON(stripe_operations_active(sh));
 508         BUG_ON(sh->batch_head);
 509
 510         pr_debug("init_stripe called, stripe %llu\n",
 511                 (unsigned long long)sector);
 512 retry:
 513         seq = read_seqcount_begin(&conf->gen_lock);
 514         sh->generation = conf->generation - previous;
 515         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 516         sh->sector = sector;
 517         stripe_set_idx(sector, conf, previous, sh);
 518         sh->state = 0;
 519
 520         for (i = sh->disks; i--; ) {
 521                 struct r5dev *dev = &sh->dev[i];
 522
 523                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 524                     test_bit(R5_LOCKED, &dev->flags)) {
 525                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 526                                (unsigned long long)sh->sector, i, dev->toread,
 527                                dev->read, dev->towrite, dev->written,
 528                                test_bit(R5_LOCKED, &dev->flags));
 529                         WARN_ON(1);
 530                 }
 531                 dev->flags = 0;
 532                 dev->sector = raid5_compute_blocknr(sh, i, previous);
 533         }
 534         if (read_seqcount_retry(&conf->gen_lock, seq))
 535                 goto retry;
 536         sh->overwrite_disks = 0;
 537         insert_hash(conf, sh);
 538         sh->cpu = smp_processor_id();
 539         set_bit(STRIPE_BATCH_READY, &sh->state);
 540 }
 541
 542 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 543                                          short generation)
 544 {
 545         struct stripe_head *sh;
 546
 547         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 548         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 549                 if (sh->sector == sector && sh->generation == generation)
 550                         return sh;
 551         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 552         return NULL;
 553 }
 554
 555 /*
 556  * Need to check if array has failed when deciding whether to:
 557  *  - start an array
 558  *  - remove non-faulty devices
 559  *  - add a spare
 560  *  - allow a reshape
 561  * This determination is simple when no reshape is happening.
 562  * However if there is a reshape, we need to carefully check
 563  * both the before and after sections.
 564  * This is because some failed devices may only affect one
 565  * of the two sections, and some non-in_sync devices may
 566  * be insync in the section most affected by failed devices.
 567  */
 568 int raid5_calc_degraded(struct r5conf *conf)
 569 {
 570         int degraded, degraded2;
 571         int i;
 572
 573         rcu_read_lock();
 574         degraded = 0;
 575         for (i = 0; i < conf->previous_raid_disks; i++) {
 576                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 577                 if (rdev && test_bit(Faulty, &rdev->flags))
 578                         rdev = rcu_dereference(conf->disks[i].replacement);
 579                 if (!rdev || test_bit(Faulty, &rdev->flags))
 580                         degraded++;
 581                 else if (test_bit(In_sync, &rdev->flags))
 582                         ;
 583                 else
 584                         /* not in-sync or faulty.
 585                          * If the reshape increases the number of devices,
 586                          * this is being recovered by the reshape, so
 587                          * this 'previous' section is not in_sync.
 588                          * If the number of devices is being reduced however,
 589                          * the device can only be part of the array if
 590                          * we are reverting a reshape, so this section will
 591                          * be in-sync.
 592                          */
 593                         if (conf->raid_disks >= conf->previous_raid_disks)
 594                                 degraded++;
 595         }
 596         rcu_read_unlock();
 597         if (conf->raid_disks == conf->previous_raid_disks)
 598                 return degraded;
 599         rcu_read_lock();
 600         degraded2 = 0;
 601         for (i = 0; i < conf->raid_disks; i++) {
 602                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 603                 if (rdev && test_bit(Faulty, &rdev->flags))
 604                         rdev = rcu_dereference(conf->disks[i].replacement);
 605                 if (!rdev || test_bit(Faulty, &rdev->flags))
 606                         degraded2++;
 607                 else if (test_bit(In_sync, &rdev->flags))
 608                         ;
 609                 else
 610                         /* not in-sync or faulty.
 611                          * If reshape increases the number of devices, this
 612                          * section has already been recovered, else it
 613                          * almost certainly hasn't.
 614                          */
 615                         if (conf->raid_disks <= conf->previous_raid_disks)
 616                                 degraded2++;
 617         }
 618         rcu_read_unlock();
 619         if (degraded2 > degraded)
 620                 return degraded2;
 621         return degraded;
 622 }
 623
 624 static int has_failed(struct r5conf *conf)
 625 {
 626         int degraded;
 627
 628         if (conf->mddev->reshape_position == MaxSector)
 629                 return conf->mddev->degraded > conf->max_degraded;
 630
 631         degraded = raid5_calc_degraded(conf);
 632         if (degraded > conf->max_degraded)
 633                 return 1;
 634         return 0;
 635 }
 636
 637 struct stripe_head *
 638 raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 639                         int previous, int noblock, int noquiesce)
 640 {
 641         struct stripe_head *sh;
 642         int hash = stripe_hash_locks_hash(sector);
 643         int inc_empty_inactive_list_flag;
 644
 645         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 646
 647         spin_lock_irq(conf->hash_locks + hash);
 648
 649         do {
 650                 wait_event_lock_irq(conf->wait_for_quiescent,
 651                                     conf->quiesce == 0 || noquiesce,
 652                                     *(conf->hash_locks + hash));
 653                 sh = __find_stripe(conf, sector, conf->generation - previous);
 654                 if (!sh) {
 655                         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 656                                 sh = get_free_stripe(conf, hash);
 657                                 if (!sh && !test_bit(R5_DID_ALLOC,
 658                                                      &conf->cache_state))
 659                                         set_bit(R5_ALLOC_MORE,
 660                                                 &conf->cache_state);
 661                         }
 662                         if (noblock && sh == NULL)
 663                                 break;
 664
 665                         r5c_check_stripe_cache_usage(conf);
 666                         if (!sh) {
 667                                 set_bit(R5_INACTIVE_BLOCKED,
 668                                         &conf->cache_state);
 669                                 r5l_wake_reclaim(conf->log, 0);
 670                                 wait_event_lock_irq(
 671                                         conf->wait_for_stripe,
 672                                         !list_empty(conf->inactive_list + hash) &&
 673                                         (atomic_read(&conf->active_stripes)
 674                                          < (conf->max_nr_stripes * 3 / 4)
 675                                          || !test_bit(R5_INACTIVE_BLOCKED,
 676                                                       &conf->cache_state)),
 677                                         *(conf->hash_locks + hash));
 678                                 clear_bit(R5_INACTIVE_BLOCKED,
 679                                           &conf->cache_state);
 680                         } else {
 681                                 init_stripe(sh, sector, previous);
 682                                 atomic_inc(&sh->count);
 683                         }
 684                 } else if (!atomic_inc_not_zero(&sh->count)) {
 685                         spin_lock(&conf->device_lock);
 686                         if (!atomic_read(&sh->count)) {
 687                                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 688                                         atomic_inc(&conf->active_stripes);
 689                                 BUG_ON(list_empty(&sh->lru) &&
 690                                        !test_bit(STRIPE_EXPANDING, &sh->state));
 691                                 inc_empty_inactive_list_flag = 0;
 692                                 if (!list_empty(conf->inactive_list + hash))
 693                                         inc_empty_inactive_list_flag = 1;
 694                                 list_del_init(&sh->lru);
 695                                 if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 696                                         atomic_inc(&conf->empty_inactive_list_nr);
 697                                 if (sh->group) {
 698                                         sh->group->stripes_cnt--;
 699                                         sh->group = NULL;
 700                                 }
 701                         }
 702                         atomic_inc(&sh->count);
 703                         spin_unlock(&conf->device_lock);
 704                 }
 705         } while (sh == NULL);
 706
 707         spin_unlock_irq(conf->hash_locks + hash);
 708         return sh;
 709 }
 710
 711 static bool is_full_stripe_write(struct stripe_head *sh)
 712 {
 713         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 714         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 715 }
 716
 717 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 718 {
 719         if (sh1 > sh2) {
 720                 spin_lock_irq(&sh2->stripe_lock);
 721                 spin_lock_nested(&sh1->stripe_lock, 1);
 722         } else {
 723                 spin_lock_irq(&sh1->stripe_lock);
 724                 spin_lock_nested(&sh2->stripe_lock, 1);
 725         }
 726 }
 727
 728 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 729 {
 730         spin_unlock(&sh1->stripe_lock);
 731         spin_unlock_irq(&sh2->stripe_lock);
 732 }
 733
 734 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 735 static bool stripe_can_batch(struct stripe_head *sh)
 736 {
 737         struct r5conf *conf = sh->raid_conf;
 738
 739         if (raid5_has_log(conf) || raid5_has_ppl(conf))
 740                 return false;
 741         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 742                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 743                 is_full_stripe_write(sh);
 744 }
 745
 746 /* we only do back search */
 747 static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
 748 {
 749         struct stripe_head *head;
 750         sector_t head_sector, tmp_sec;
 751         int hash;
 752         int dd_idx;
 753         int inc_empty_inactive_list_flag;
 754
 755         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 756         tmp_sec = sh->sector;
 757         if (!sector_div(tmp_sec, conf->chunk_sectors))
 758                 return;
 759         head_sector = sh->sector - STRIPE_SECTORS;
 760
 761         hash = stripe_hash_locks_hash(head_sector);
 762         spin_lock_irq(conf->hash_locks + hash);
 763         head = __find_stripe(conf, head_sector, conf->generation);
 764         if (head && !atomic_inc_not_zero(&head->count)) {
 765                 spin_lock(&conf->device_lock);
 766                 if (!atomic_read(&head->count)) {
 767                         if (!test_bit(STRIPE_HANDLE, &head->state))
 768                                 atomic_inc(&conf->active_stripes);
 769                         BUG_ON(list_empty(&head->lru) &&
 770                                !test_bit(STRIPE_EXPANDING, &head->state));
 771                         inc_empty_inactive_list_flag = 0;
 772                         if (!list_empty(conf->inactive_list + hash))
 773                                 inc_empty_inactive_list_flag = 1;
 774                         list_del_init(&head->lru);
 775                         if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 776                                 atomic_inc(&conf->empty_inactive_list_nr);
 777                         if (head->group) {
 778                                 head->group->stripes_cnt--;
 779                                 head->group = NULL;
 780                         }
 781                 }
 782                 atomic_inc(&head->count);
 783                 spin_unlock(&conf->device_lock);
 784         }
 785         spin_unlock_irq(conf->hash_locks + hash);
 786
 787         if (!head)
 788                 return;
 789         if (!stripe_can_batch(head))
 790                 goto out;
 791
 792         lock_two_stripes(head, sh);
 793         /* clear_batch_ready clear the flag */
 794         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 795                 goto unlock_out;
 796
 797         if (sh->batch_head)
 798                 goto unlock_out;
 799
 800         dd_idx = 0;
 801         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 802                 dd_idx++;
 803         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 804             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 805                 goto unlock_out;
 806
 807         if (head->batch_head) {
 808                 spin_lock(&head->batch_head->batch_lock);
 809                 /* This batch list is already running */
 810                 if (!stripe_can_batch(head)) {
 811                         spin_unlock(&head->batch_head->batch_lock);
 812                         goto unlock_out;
 813                 }
 814                 /*
 815                  * We must assign batch_head of this stripe within the
 816                  * batch_lock, otherwise clear_batch_ready of batch head
 817                  * stripe could clear BATCH_READY bit of this stripe and
 818                  * this stripe->batch_head doesn't get assigned, which
 819                  * could confuse clear_batch_ready for this stripe
 820                  */
 821                 sh->batch_head = head->batch_head;
 822
 823                 /*
 824                  * at this point, head's BATCH_READY could be cleared, but we
 825                  * can still add the stripe to batch list
 826                  */
 827                 list_add(&sh->batch_list, &head->batch_list);
 828                 spin_unlock(&head->batch_head->batch_lock);
 829         } else {
 830                 head->batch_head = head;
 831                 sh->batch_head = head->batch_head;
 832                 spin_lock(&head->batch_lock);
 833                 list_add_tail(&sh->batch_list, &head->batch_list);
 834                 spin_unlock(&head->batch_lock);
 835         }
 836
 837         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 838                 if (atomic_dec_return(&conf->preread_active_stripes)
 839                     < IO_THRESHOLD)
 840                         md_wakeup_thread(conf->mddev->thread);
 841
 842         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 843                 int seq = sh->bm_seq;
 844                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 845                     sh->batch_head->bm_seq > seq)
 846                         seq = sh->batch_head->bm_seq;
 847                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 848                 sh->batch_head->bm_seq = seq;
 849         }
 850
 851         atomic_inc(&sh->count);
 852 unlock_out:
 853         unlock_two_stripes(head, sh);
 854 out:
 855         raid5_release_stripe(head);
 856 }
 857
 858 /* Determine if 'data_offset' or 'new_data_offset' should be used
 859  * in this stripe_head.
 860  */
 861 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
 862 {
 863         sector_t progress = conf->reshape_progress;
 864         /* Need a memory barrier to make sure we see the value
 865          * of conf->generation, or ->data_offset that was set before
 866          * reshape_progress was updated.
 867          */
 868         smp_rmb();
 869         if (progress == MaxSector)
 870                 return 0;
 871         if (sh->generation == conf->generation - 1)
 872                 return 0;
 873         /* We are in a reshape, and this is a new-generation stripe,
 874          * so use new_data_offset.
 875          */
 876         return 1;
 877 }
 878
 879 static void dispatch_bio_list(struct bio_list *tmp)
 880 {
 881         struct bio *bio;
 882
 883         while ((bio = bio_list_pop(tmp)))
 884                 generic_make_request(bio);
 885 }
 886
 887 static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
 888 {
 889         const struct r5pending_data *da = list_entry(a,
 890                                 struct r5pending_data, sibling);
 891         const struct r5pending_data *db = list_entry(b,
 892                                 struct r5pending_data, sibling);
 893         if (da->sector > db->sector)
 894                 return 1;
 895         if (da->sector < db->sector)
 896                 return -1;
 897         return 0;
 898 }
 899
 900 static void dispatch_defer_bios(struct r5conf *conf, int target,
 901                                 struct bio_list *list)
 902 {
 903         struct r5pending_data *data;
 904         struct list_head *first, *next = NULL;
 905         int cnt = 0;
 906
 907         if (conf->pending_data_cnt == 0)
 908                 return;
 909
 910         list_sort(NULL, &conf->pending_list, cmp_stripe);
 911
 912         first = conf->pending_list.next;
 913
 914         /* temporarily move the head */
 915         if (conf->next_pending_data)
 916                 list_move_tail(&conf->pending_list,
 917                                 &conf->next_pending_data->sibling);
 918
 919         while (!list_empty(&conf->pending_list)) {
 920                 data = list_first_entry(&conf->pending_list,
 921                         struct r5pending_data, sibling);
 922                 if (&data->sibling == first)
 923                         first = data->sibling.next;
 924                 next = data->sibling.next;
 925
 926                 bio_list_merge(list, &data->bios);
 927                 list_move(&data->sibling, &conf->free_list);
 928                 cnt++;
 929                 if (cnt >= target)
 930                         break;
 931         }
 932         conf->pending_data_cnt -= cnt;
 933         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
 934
 935         if (next != &conf->pending_list)
 936                 conf->next_pending_data = list_entry(next,
 937                                 struct r5pending_data, sibling);
 938         else
 939                 conf->next_pending_data = NULL;
 940         /* list isn't empty */
 941         if (first != &conf->pending_list)
 942                 list_move_tail(&conf->pending_list, first);
 943 }
 944
 945 static void flush_deferred_bios(struct r5conf *conf)
 946 {
 947         struct bio_list tmp = BIO_EMPTY_LIST;
 948
 949         if (conf->pending_data_cnt == 0)
 950                 return;
 951
 952         spin_lock(&conf->pending_bios_lock);
 953         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
 954         BUG_ON(conf->pending_data_cnt != 0);
 955         spin_unlock(&conf->pending_bios_lock);
 956
 957         dispatch_bio_list(&tmp);
 958 }
 959
 960 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
 961                                 struct bio_list *bios)
 962 {
 963         struct bio_list tmp = BIO_EMPTY_LIST;
 964         struct r5pending_data *ent;
 965
 966         spin_lock(&conf->pending_bios_lock);
 967         ent = list_first_entry(&conf->free_list, struct r5pending_data,
 968                                                         sibling);
 969         list_move_tail(&ent->sibling, &conf->pending_list);
 970         ent->sector = sector;
 971         bio_list_init(&ent->bios);
 972         bio_list_merge(&ent->bios, bios);
 973         conf->pending_data_cnt++;
 974         if (conf->pending_data_cnt >= PENDING_IO_MAX)
 975                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
 976
 977         spin_unlock(&conf->pending_bios_lock);
 978
 979         dispatch_bio_list(&tmp);
 980 }
 981
 982 static void
 983 raid5_end_read_request(struct bio *bi);
 984 static void
 985 raid5_end_write_request(struct bio *bi);
 986
 987 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 988 {
 989         struct r5conf *conf = sh->raid_conf;
 990         int i, disks = sh->disks;
 991         struct stripe_head *head_sh = sh;
 992         struct bio_list pending_bios = BIO_EMPTY_LIST;
 993         bool should_defer;
 994
 995         might_sleep();
 996
 997         if (log_stripe(sh, s) == 0)
 998                 return;
 999
1000         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1001
1002         for (i = disks; i--; ) {
1003                 int op, op_flags = 0;
1004                 int replace_only = 0;
1005                 struct bio *bi, *rbi;
1006                 struct md_rdev *rdev, *rrdev = NULL;
1007
1008                 sh = head_sh;
1009                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1010                         op = REQ_OP_WRITE;
1011                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1012                                 op_flags = REQ_FUA;
1013                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1014                                 op = REQ_OP_DISCARD;
1015                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1016                         op = REQ_OP_READ;
1017                 else if (test_and_clear_bit(R5_WantReplace,
1018                                             &sh->dev[i].flags)) {
1019                         op = REQ_OP_WRITE;
1020                         replace_only = 1;
1021                 } else
1022                         continue;
1023                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1024                         op_flags |= REQ_SYNC;
1025
1026 again:
1027                 bi = &sh->dev[i].req;
1028                 rbi = &sh->dev[i].rreq; /* For writing to replacement */
1029
1030                 rcu_read_lock();
1031                 rrdev = rcu_dereference(conf->disks[i].replacement);
1032                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1033                 rdev = rcu_dereference(conf->disks[i].rdev);
1034                 if (!rdev) {
1035                         rdev = rrdev;
1036                         rrdev = NULL;
1037                 }
1038                 if (op_is_write(op)) {
1039                         if (replace_only)
1040                                 rdev = NULL;
1041                         if (rdev == rrdev)
1042                                 /* We raced and saw duplicates */
1043                                 rrdev = NULL;
1044                 } else {
1045                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1046                                 rdev = rrdev;
1047                         rrdev = NULL;
1048                 }
1049
1050                 if (rdev && test_bit(Faulty, &rdev->flags))
1051                         rdev = NULL;
1052                 if (rdev)
1053                         atomic_inc(&rdev->nr_pending);
1054                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1055                         rrdev = NULL;
1056                 if (rrdev)
1057                         atomic_inc(&rrdev->nr_pending);
1058                 rcu_read_unlock();
1059
1060                 /* We have already checked bad blocks for reads.  Now
1061                  * need to check for writes.  We never accept write errors
1062                  * on the replacement, so we don't to check rrdev.
1063                  */
1064                 while (op_is_write(op) && rdev &&
1065                        test_bit(WriteErrorSeen, &rdev->flags)) {
1066                         sector_t first_bad;
1067                         int bad_sectors;
1068                         int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
1069                                               &first_bad, &bad_sectors);
1070                         if (!bad)
1071                                 break;
1072
1073                         if (bad < 0) {
1074                                 set_bit(BlockedBadBlocks, &rdev->flags);
1075                                 if (!conf->mddev->external &&
1076                                     conf->mddev->sb_flags) {
1077                                         /* It is very unlikely, but we might
1078                                          * still need to write out the
1079                                          * bad block log - better give it
1080                                          * a chance*/
1081                                         md_check_recovery(conf->mddev);
1082                                 }
1083                                 /*
1084                                  * Because md_wait_for_blocked_rdev
1085                                  * will dec nr_pending, we must
1086                                  * increment it first.
1087                                  */
1088                                 atomic_inc(&rdev->nr_pending);
1089                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1090                         } else {
1091                                 /* Acknowledged bad block - skip the write */
1092                                 rdev_dec_pending(rdev, conf->mddev);
1093                                 rdev = NULL;
1094                         }
1095                 }
1096
1097                 if (rdev) {
1098                         if (s->syncing || s->expanding || s->expanded
1099                             || s->replacing)
1100                                 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1101
1102                         set_bit(STRIPE_IO_STARTED, &sh->state);
1103
1104                         bio_set_dev(bi, rdev->bdev);
1105                         bio_set_op_attrs(bi, op, op_flags);
1106                         bi->bi_end_io = op_is_write(op)
1107                                 ? raid5_end_write_request
1108                                 : raid5_end_read_request;
1109                         bi->bi_private = sh;
1110
1111                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1112                                 __func__, (unsigned long long)sh->sector,
1113                                 bi->bi_opf, i);
1114                         atomic_inc(&sh->count);
1115                         if (sh != head_sh)
1116                                 atomic_inc(&head_sh->count);
1117                         if (use_new_offset(conf, sh))
1118                                 bi->bi_iter.bi_sector = (sh->sector
1119                                                  + rdev->new_data_offset);
1120                         else
1121                                 bi->bi_iter.bi_sector = (sh->sector
1122                                                  + rdev->data_offset);
1123                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1124                                 bi->bi_opf |= REQ_NOMERGE;
1125
1126                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1127                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1128
1129                         if (!op_is_write(op) &&
1130                             test_bit(R5_InJournal, &sh->dev[i].flags))
1131                                 /*
1132                                  * issuing read for a page in journal, this
1133                                  * must be preparing for prexor in rmw; read
1134                                  * the data into orig_page
1135                                  */
1136                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1137                         else
1138                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1139                         bi->bi_vcnt = 1;
1140                         bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1141                         bi->bi_io_vec[0].bv_offset = 0;
1142                         bi->bi_iter.bi_size = STRIPE_SIZE;
1143                         /*
1144                          * If this is discard request, set bi_vcnt 0. We don't
1145                          * want to confuse SCSI because SCSI will replace payload
1146                          */
1147                         if (op == REQ_OP_DISCARD)
1148                                 bi->bi_vcnt = 0;
1149                         if (rrdev)
1150                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1151
1152                         if (conf->mddev->gendisk)
1153                                 trace_block_bio_remap(bi->bi_disk->queue,
1154                                                       bi, disk_devt(conf->mddev->gendisk),
1155                                                       sh->dev[i].sector);
1156                         if (should_defer && op_is_write(op))
1157                                 bio_list_add(&pending_bios, bi);
1158                         else
1159                                 generic_make_request(bi);
1160                 }
1161                 if (rrdev) {
1162                         if (s->syncing || s->expanding || s->expanded
1163                             || s->replacing)
1164                                 md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
1165
1166                         set_bit(STRIPE_IO_STARTED, &sh->state);
1167
1168                         bio_set_dev(rbi, rrdev->bdev);
1169                         bio_set_op_attrs(rbi, op, op_flags);
1170                         BUG_ON(!op_is_write(op));
1171                         rbi->bi_end_io = raid5_end_write_request;
1172                         rbi->bi_private = sh;
1173
1174                         pr_debug("%s: for %llu schedule op %d on "
1175                                  "replacement disc %d\n",
1176                                 __func__, (unsigned long long)sh->sector,
1177                                 rbi->bi_opf, i);
1178                         atomic_inc(&sh->count);
1179                         if (sh != head_sh)
1180                                 atomic_inc(&head_sh->count);
1181                         if (use_new_offset(conf, sh))
1182                                 rbi->bi_iter.bi_sector = (sh->sector
1183                                                   + rrdev->new_data_offset);
1184                         else
1185                                 rbi->bi_iter.bi_sector = (sh->sector
1186                                                   + rrdev->data_offset);
1187                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1188                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1189                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1190                         rbi->bi_vcnt = 1;
1191                         rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1192                         rbi->bi_io_vec[0].bv_offset = 0;
1193                         rbi->bi_iter.bi_size = STRIPE_SIZE;
1194                         /*
1195                          * If this is discard request, set bi_vcnt 0. We don't
1196                          * want to confuse SCSI because SCSI will replace payload
1197                          */
1198                         if (op == REQ_OP_DISCARD)
1199                                 rbi->bi_vcnt = 0;
1200                         if (conf->mddev->gendisk)
1201                                 trace_block_bio_remap(rbi->bi_disk->queue,
1202                                                       rbi, disk_devt(conf->mddev->gendisk),
1203                                                       sh->dev[i].sector);
1204                         if (should_defer && op_is_write(op))
1205                                 bio_list_add(&pending_bios, rbi);
1206                         else
1207                                 generic_make_request(rbi);
1208                 }
1209                 if (!rdev && !rrdev) {
1210                         if (op_is_write(op))
1211                                 set_bit(STRIPE_DEGRADED, &sh->state);
1212                         pr_debug("skip op %d on disc %d for sector %llu\n",
1213                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1214                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1215                         set_bit(STRIPE_HANDLE, &sh->state);
1216                 }
1217
1218                 if (!head_sh->batch_head)
1219                         continue;
1220                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1221                                       batch_list);
1222                 if (sh != head_sh)
1223                         goto again;
1224         }
1225
1226         if (should_defer && !bio_list_empty(&pending_bios))
1227                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1228 }
1229
1230 static struct dma_async_tx_descriptor *
1231 async_copy_data(int frombio, struct bio *bio, struct page **page,
1232         sector_t sector, struct dma_async_tx_descriptor *tx,
1233         struct stripe_head *sh, int no_skipcopy)
1234 {
1235         struct bio_vec bvl;
1236         struct bvec_iter iter;
1237         struct page *bio_page;
1238         int page_offset;
1239         struct async_submit_ctl submit;
1240         enum async_tx_flags flags = 0;
1241
1242         if (bio->bi_iter.bi_sector >= sector)
1243                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1244         else
1245                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1246
1247         if (frombio)
1248                 flags |= ASYNC_TX_FENCE;
1249         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1250
1251         bio_for_each_segment(bvl, bio, iter) {
1252                 int len = bvl.bv_len;
1253                 int clen;
1254                 int b_offset = 0;
1255
1256                 if (page_offset < 0) {
1257                         b_offset = -page_offset;
1258                         page_offset += b_offset;
1259                         len -= b_offset;
1260                 }
1261
1262                 if (len > 0 && page_offset + len > STRIPE_SIZE)
1263                         clen = STRIPE_SIZE - page_offset;
1264                 else
1265                         clen = len;
1266
1267                 if (clen > 0) {
1268                         b_offset += bvl.bv_offset;
1269                         bio_page = bvl.bv_page;
1270                         if (frombio) {
1271                                 if (sh->raid_conf->skip_copy &&
1272                                     b_offset == 0 && page_offset == 0 &&
1273                                     clen == STRIPE_SIZE &&
1274                                     !no_skipcopy)
1275                                         *page = bio_page;
1276                                 else
1277                                         tx = async_memcpy(*page, bio_page, page_offset,
1278                                                   b_offset, clen, &submit);
1279                         } else
1280                                 tx = async_memcpy(bio_page, *page, b_offset,
1281                                                   page_offset, clen, &submit);
1282                 }
1283                 /* chain the operations */
1284                 submit.depend_tx = tx;
1285
1286                 if (clen < len) /* hit end of page */
1287                         break;
1288                 page_offset +=  len;
1289         }
1290
1291         return tx;
1292 }
1293
1294 static void ops_complete_biofill(void *stripe_head_ref)
1295 {
1296         struct stripe_head *sh = stripe_head_ref;
1297         int i;
1298
1299         pr_debug("%s: stripe %llu\n", __func__,
1300                 (unsigned long long)sh->sector);
1301
1302         /* clear completed biofills */
1303         for (i = sh->disks; i--; ) {
1304                 struct r5dev *dev = &sh->dev[i];
1305
1306                 /* acknowledge completion of a biofill operation */
1307                 /* and check if we need to reply to a read request,
1308                  * new R5_Wantfill requests are held off until
1309                  * !STRIPE_BIOFILL_RUN
1310                  */
1311                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1312                         struct bio *rbi, *rbi2;
1313
1314                         BUG_ON(!dev->read);
1315                         rbi = dev->read;
1316                         dev->read = NULL;
1317                         while (rbi && rbi->bi_iter.bi_sector <
1318                                 dev->sector + STRIPE_SECTORS) {
1319                                 rbi2 = r5_next_bio(rbi, dev->sector);
1320                                 bio_endio(rbi);
1321                                 rbi = rbi2;
1322                         }
1323                 }
1324         }
1325         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1326
1327         set_bit(STRIPE_HANDLE, &sh->state);
1328         raid5_release_stripe(sh);
1329 }
1330
1331 static void ops_run_biofill(struct stripe_head *sh)
1332 {
1333         struct dma_async_tx_descriptor *tx = NULL;
1334         struct async_submit_ctl submit;
1335         int i;
1336
1337         BUG_ON(sh->batch_head);
1338         pr_debug("%s: stripe %llu\n", __func__,
1339                 (unsigned long long)sh->sector);
1340
1341         for (i = sh->disks; i--; ) {
1342                 struct r5dev *dev = &sh->dev[i];
1343                 if (test_bit(R5_Wantfill, &dev->flags)) {
1344                         struct bio *rbi;
1345                         spin_lock_irq(&sh->stripe_lock);
1346                         dev->read = rbi = dev->toread;
1347                         dev->toread = NULL;
1348                         spin_unlock_irq(&sh->stripe_lock);
1349                         while (rbi && rbi->bi_iter.bi_sector <
1350                                 dev->sector + STRIPE_SECTORS) {
1351                                 tx = async_copy_data(0, rbi, &dev->page,
1352                                                      dev->sector, tx, sh, 0);
1353                                 rbi = r5_next_bio(rbi, dev->sector);
1354                         }
1355                 }
1356         }
1357
1358         atomic_inc(&sh->count);
1359         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1360         async_trigger_callback(&submit);
1361 }
1362
1363 static void mark_target_uptodate(struct stripe_head *sh, int target)
1364 {
1365         struct r5dev *tgt;
1366
1367         if (target < 0)
1368                 return;
1369
1370         tgt = &sh->dev[target];
1371         set_bit(R5_UPTODATE, &tgt->flags);
1372         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1373         clear_bit(R5_Wantcompute, &tgt->flags);
1374 }
1375
1376 static void ops_complete_compute(void *stripe_head_ref)
1377 {
1378         struct stripe_head *sh = stripe_head_ref;
1379
1380         pr_debug("%s: stripe %llu\n", __func__,
1381                 (unsigned long long)sh->sector);
1382
1383         /* mark the computed target(s) as uptodate */
1384         mark_target_uptodate(sh, sh->ops.target);
1385         mark_target_uptodate(sh, sh->ops.target2);
1386
1387         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1388         if (sh->check_state == check_state_compute_run)
1389                 sh->check_state = check_state_compute_result;
1390         set_bit(STRIPE_HANDLE, &sh->state);
1391         raid5_release_stripe(sh);
1392 }
1393
1394 /* return a pointer to the address conversion region of the scribble buffer */
1395 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1396                                  struct raid5_percpu *percpu, int i)
1397 {
1398         void *addr;
1399
1400         addr = flex_array_get(percpu->scribble, i);
1401         return addr + sizeof(struct page *) * (sh->disks + 2);
1402 }
1403
1404 /* return a pointer to the address conversion region of the scribble buffer */
1405 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1406 {
1407         void *addr;
1408
1409         addr = flex_array_get(percpu->scribble, i);
1410         return addr;
1411 }
1412
1413 static struct dma_async_tx_descriptor *
1414 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1415 {
1416         int disks = sh->disks;
1417         struct page **xor_srcs = to_addr_page(percpu, 0);
1418         int target = sh->ops.target;
1419         struct r5dev *tgt = &sh->dev[target];
1420         struct page *xor_dest = tgt->page;
1421         int count = 0;
1422         struct dma_async_tx_descriptor *tx;
1423         struct async_submit_ctl submit;
1424         int i;
1425
1426         BUG_ON(sh->batch_head);
1427
1428         pr_debug("%s: stripe %llu block: %d\n",
1429                 __func__, (unsigned long long)sh->sector, target);
1430         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1431
1432         for (i = disks; i--; )
1433                 if (i != target)
1434                         xor_srcs[count++] = sh->dev[i].page;
1435
1436         atomic_inc(&sh->count);
1437
1438         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1439                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1440         if (unlikely(count == 1))
1441                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1442         else
1443                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1444
1445         return tx;
1446 }
1447
1448 /* set_syndrome_sources - populate source buffers for gen_syndrome
1449  * @srcs - (struct page *) array of size sh->disks
1450  * @sh - stripe_head to parse
1451  *
1452  * Populates srcs in proper layout order for the stripe and returns the
1453  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1454  * destination buffer is recorded in srcs[count] and the Q destination
1455  * is recorded in srcs[count+1]].
1456  */
1457 static int set_syndrome_sources(struct page **srcs,
1458                                 struct stripe_head *sh,
1459                                 int srctype)
1460 {
1461         int disks = sh->disks;
1462         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1463         int d0_idx = raid6_d0(sh);
1464         int count;
1465         int i;
1466
1467         for (i = 0; i < disks; i++)
1468                 srcs[i] = NULL;
1469
1470         count = 0;
1471         i = d0_idx;
1472         do {
1473                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1474                 struct r5dev *dev = &sh->dev[i];
1475
1476                 if (i == sh->qd_idx || i == sh->pd_idx ||
1477                     (srctype == SYNDROME_SRC_ALL) ||
1478                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1479                      (test_bit(R5_Wantdrain, &dev->flags) ||
1480                       test_bit(R5_InJournal, &dev->flags))) ||
1481                     (srctype == SYNDROME_SRC_WRITTEN &&
1482                      (dev->written ||
1483                       test_bit(R5_InJournal, &dev->flags)))) {
1484                         if (test_bit(R5_InJournal, &dev->flags))
1485                                 srcs[slot] = sh->dev[i].orig_page;
1486                         else
1487                                 srcs[slot] = sh->dev[i].page;
1488                 }
1489                 i = raid6_next_disk(i, disks);
1490         } while (i != d0_idx);
1491
1492         return syndrome_disks;
1493 }
1494
1495 static struct dma_async_tx_descriptor *
1496 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1497 {
1498         int disks = sh->disks;
1499         struct page **blocks = to_addr_page(percpu, 0);
1500         int target;
1501         int qd_idx = sh->qd_idx;
1502         struct dma_async_tx_descriptor *tx;
1503         struct async_submit_ctl submit;
1504         struct r5dev *tgt;
1505         struct page *dest;
1506         int i;
1507         int count;
1508
1509         BUG_ON(sh->batch_head);
1510         if (sh->ops.target < 0)
1511                 target = sh->ops.target2;
1512         else if (sh->ops.target2 < 0)
1513                 target = sh->ops.target;
1514         else
1515                 /* we should only have one valid target */
1516                 BUG();
1517         BUG_ON(target < 0);
1518         pr_debug("%s: stripe %llu block: %d\n",
1519                 __func__, (unsigned long long)sh->sector, target);
1520
1521         tgt = &sh->dev[target];
1522         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1523         dest = tgt->page;
1524
1525         atomic_inc(&sh->count);
1526
1527         if (target == qd_idx) {
1528                 count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1529                 blocks[count] = NULL; /* regenerating p is not necessary */
1530                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1531                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1532                                   ops_complete_compute, sh,
1533                                   to_addr_conv(sh, percpu, 0));
1534                 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1535         } else {
1536                 /* Compute any data- or p-drive using XOR */
1537                 count = 0;
1538                 for (i = disks; i-- ; ) {
1539                         if (i == target || i == qd_idx)
1540                                 continue;
1541                         blocks[count++] = sh->dev[i].page;
1542                 }
1543
1544                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1545                                   NULL, ops_complete_compute, sh,
1546                                   to_addr_conv(sh, percpu, 0));
1547                 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
1548         }
1549
1550         return tx;
1551 }
1552
1553 static struct dma_async_tx_descriptor *
1554 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1555 {
1556         int i, count, disks = sh->disks;
1557         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1558         int d0_idx = raid6_d0(sh);
1559         int faila = -1, failb = -1;
1560         int target = sh->ops.target;
1561         int target2 = sh->ops.target2;
1562         struct r5dev *tgt = &sh->dev[target];
1563         struct r5dev *tgt2 = &sh->dev[target2];
1564         struct dma_async_tx_descriptor *tx;
1565         struct page **blocks = to_addr_page(percpu, 0);
1566         struct async_submit_ctl submit;
1567
1568         BUG_ON(sh->batch_head);
1569         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1570                  __func__, (unsigned long long)sh->sector, target, target2);
1571         BUG_ON(target < 0 || target2 < 0);
1572         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1573         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1574
1575         /* we need to open-code set_syndrome_sources to handle the
1576          * slot number conversion for 'faila' and 'failb'
1577          */
1578         for (i = 0; i < disks ; i++)
1579                 blocks[i] = NULL;
1580         count = 0;
1581         i = d0_idx;
1582         do {
1583                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1584
1585                 blocks[slot] = sh->dev[i].page;
1586
1587                 if (i == target)
1588                         faila = slot;
1589                 if (i == target2)
1590                         failb = slot;
1591                 i = raid6_next_disk(i, disks);
1592         } while (i != d0_idx);
1593
1594         BUG_ON(faila == failb);
1595         if (failb < faila)
1596                 swap(faila, failb);
1597         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1598                  __func__, (unsigned long long)sh->sector, faila, failb);
1599
1600         atomic_inc(&sh->count);
1601
1602         if (failb == syndrome_disks+1) {
1603                 /* Q disk is one of the missing disks */
1604                 if (faila == syndrome_disks) {
1605                         /* Missing P+Q, just recompute */
1606                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1607                                           ops_complete_compute, sh,
1608                                           to_addr_conv(sh, percpu, 0));
1609                         return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1610                                                   STRIPE_SIZE, &submit);
1611                 } else {
1612                         struct page *dest;
1613                         int data_target;
1614                         int qd_idx = sh->qd_idx;
1615
1616                         /* Missing D+Q: recompute D from P, then recompute Q */
1617                         if (target == qd_idx)
1618                                 data_target = target2;
1619                         else
1620                                 data_target = target;
1621
1622                         count = 0;
1623                         for (i = disks; i-- ; ) {
1624                                 if (i == data_target || i == qd_idx)
1625                                         continue;
1626                                 blocks[count++] = sh->dev[i].page;
1627                         }
1628                         dest = sh->dev[data_target].page;
1629                         init_async_submit(&submit,
1630                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1631                                           NULL, NULL, NULL,
1632                                           to_addr_conv(sh, percpu, 0));
1633                         tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
1634                                        &submit);
1635
1636                         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1637                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1638                                           ops_complete_compute, sh,
1639                                           to_addr_conv(sh, percpu, 0));
1640                         return async_gen_syndrome(blocks, 0, count+2,
1641                                                   STRIPE_SIZE, &submit);
1642                 }
1643         } else {
1644                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1645                                   ops_complete_compute, sh,
1646                                   to_addr_conv(sh, percpu, 0));
1647                 if (failb == syndrome_disks) {
1648                         /* We're missing D+P. */
1649                         return async_raid6_datap_recov(syndrome_disks+2,
1650                                                        STRIPE_SIZE, faila,
1651                                                        blocks, &submit);
1652                 } else {
1653                         /* We're missing D+D. */
1654                         return async_raid6_2data_recov(syndrome_disks+2,
1655                                                        STRIPE_SIZE, faila, failb,
1656                                                        blocks, &submit);
1657                 }
1658         }
1659 }
1660
1661 static void ops_complete_prexor(void *stripe_head_ref)
1662 {
1663         struct stripe_head *sh = stripe_head_ref;
1664
1665         pr_debug("%s: stripe %llu\n", __func__,
1666                 (unsigned long long)sh->sector);
1667
1668         if (r5c_is_writeback(sh->raid_conf->log))
1669                 /*
1670                  * raid5-cache write back uses orig_page during prexor.
1671                  * After prexor, it is time to free orig_page
1672                  */
1673                 r5c_release_extra_page(sh);
1674 }
1675
1676 static struct dma_async_tx_descriptor *
1677 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1678                 struct dma_async_tx_descriptor *tx)
1679 {
1680         int disks = sh->disks;
1681         struct page **xor_srcs = to_addr_page(percpu, 0);
1682         int count = 0, pd_idx = sh->pd_idx, i;
1683         struct async_submit_ctl submit;
1684
1685         /* existing parity data subtracted */
1686         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1687
1688         BUG_ON(sh->batch_head);
1689         pr_debug("%s: stripe %llu\n", __func__,
1690                 (unsigned long long)sh->sector);
1691
1692         for (i = disks; i--; ) {
1693                 struct r5dev *dev = &sh->dev[i];
1694                 /* Only process blocks that are known to be uptodate */
1695                 if (test_bit(R5_InJournal, &dev->flags))
1696                         xor_srcs[count++] = dev->orig_page;
1697                 else if (test_bit(R5_Wantdrain, &dev->flags))
1698                         xor_srcs[count++] = dev->page;
1699         }
1700
1701         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1702                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1703         tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1704
1705         return tx;
1706 }
1707
1708 static struct dma_async_tx_descriptor *
1709 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1710                 struct dma_async_tx_descriptor *tx)
1711 {
1712         struct page **blocks = to_addr_page(percpu, 0);
1713         int count;
1714         struct async_submit_ctl submit;
1715
1716         pr_debug("%s: stripe %llu\n", __func__,
1717                 (unsigned long long)sh->sector);
1718
1719         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
1720
1721         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1722                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1723         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1724
1725         return tx;
1726 }
1727
1728 static struct dma_async_tx_descriptor *
1729 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1730 {
1731         struct r5conf *conf = sh->raid_conf;
1732         int disks = sh->disks;
1733         int i;
1734         struct stripe_head *head_sh = sh;
1735
1736         pr_debug("%s: stripe %llu\n", __func__,
1737                 (unsigned long long)sh->sector);
1738
1739         for (i = disks; i--; ) {
1740                 struct r5dev *dev;
1741                 struct bio *chosen;
1742
1743                 sh = head_sh;
1744                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1745                         struct bio *wbi;
1746
1747 again:
1748                         dev = &sh->dev[i];
1749                         /*
1750                          * clear R5_InJournal, so when rewriting a page in
1751                          * journal, it is not skipped by r5l_log_stripe()
1752                          */
1753                         clear_bit(R5_InJournal, &dev->flags);
1754                         spin_lock_irq(&sh->stripe_lock);
1755                         chosen = dev->towrite;
1756                         dev->towrite = NULL;
1757                         sh->overwrite_disks = 0;
1758                         BUG_ON(dev->written);
1759                         wbi = dev->written = chosen;
1760                         spin_unlock_irq(&sh->stripe_lock);
1761                         WARN_ON(dev->page != dev->orig_page);
1762
1763                         while (wbi && wbi->bi_iter.bi_sector <
1764                                 dev->sector + STRIPE_SECTORS) {
1765                                 if (wbi->bi_opf & REQ_FUA)
1766                                         set_bit(R5_WantFUA, &dev->flags);
1767                                 if (wbi->bi_opf & REQ_SYNC)
1768                                         set_bit(R5_SyncIO, &dev->flags);
1769                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1770                                         set_bit(R5_Discard, &dev->flags);
1771                                 else {
1772                                         tx = async_copy_data(1, wbi, &dev->page,
1773                                                              dev->sector, tx, sh,
1774                                                              r5c_is_writeback(conf->log));
1775                                         if (dev->page != dev->orig_page &&
1776                                             !r5c_is_writeback(conf->log)) {
1777                                                 set_bit(R5_SkipCopy, &dev->flags);
1778                                                 clear_bit(R5_UPTODATE, &dev->flags);
1779                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1780                                         }
1781                                 }
1782                                 wbi = r5_next_bio(wbi, dev->sector);
1783                         }
1784
1785                         if (head_sh->batch_head) {
1786                                 sh = list_first_entry(&sh->batch_list,
1787                                                       struct stripe_head,
1788                                                       batch_list);
1789                                 if (sh == head_sh)
1790                                         continue;
1791                                 goto again;
1792                         }
1793                 }
1794         }
1795
1796         return tx;
1797 }
1798
1799 static void ops_complete_reconstruct(void *stripe_head_ref)
1800 {
1801         struct stripe_head *sh = stripe_head_ref;
1802         int disks = sh->disks;
1803         int pd_idx = sh->pd_idx;
1804         int qd_idx = sh->qd_idx;
1805         int i;
1806         bool fua = false, sync = false, discard = false;
1807
1808         pr_debug("%s: stripe %llu\n", __func__,
1809                 (unsigned long long)sh->sector);
1810
1811         for (i = disks; i--; ) {
1812                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1813                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1814                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1815         }
1816
1817         for (i = disks; i--; ) {
1818                 struct r5dev *dev = &sh->dev[i];
1819
1820                 if (dev->written || i == pd_idx || i == qd_idx) {
1821                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
1822                                 set_bit(R5_UPTODATE, &dev->flags);
1823                                 if (test_bit(STRIPE_EXPAND_READY, &sh->state))
1824                                         set_bit(R5_Expanded, &dev->flags);
1825                         }
1826                         if (fua)
1827                                 set_bit(R5_WantFUA, &dev->flags);
1828                         if (sync)
1829                                 set_bit(R5_SyncIO, &dev->flags);
1830                 }
1831         }
1832
1833         if (sh->reconstruct_state == reconstruct_state_drain_run)
1834                 sh->reconstruct_state = reconstruct_state_drain_result;
1835         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1836                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1837         else {
1838                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1839                 sh->reconstruct_state = reconstruct_state_result;
1840         }
1841
1842         set_bit(STRIPE_HANDLE, &sh->state);
1843         raid5_release_stripe(sh);
1844 }
1845
1846 static void
1847 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1848                      struct dma_async_tx_descriptor *tx)
1849 {
1850         int disks = sh->disks;
1851         struct page **xor_srcs;
1852         struct async_submit_ctl submit;
1853         int count, pd_idx = sh->pd_idx, i;
1854         struct page *xor_dest;
1855         int prexor = 0;
1856         unsigned long flags;
1857         int j = 0;
1858         struct stripe_head *head_sh = sh;
1859         int last_stripe;
1860
1861         pr_debug("%s: stripe %llu\n", __func__,
1862                 (unsigned long long)sh->sector);
1863
1864         for (i = 0; i < sh->disks; i++) {
1865                 if (pd_idx == i)
1866                         continue;
1867                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1868                         break;
1869         }
1870         if (i >= sh->disks) {
1871                 atomic_inc(&sh->count);
1872                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
1873                 ops_complete_reconstruct(sh);
1874                 return;
1875         }
1876 again:
1877         count = 0;
1878         xor_srcs = to_addr_page(percpu, j);
1879         /* check if prexor is active which means only process blocks
1880          * that are part of a read-modify-write (written)
1881          */
1882         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1883                 prexor = 1;
1884                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1885                 for (i = disks; i--; ) {
1886                         struct r5dev *dev = &sh->dev[i];
1887                         if (head_sh->dev[i].written ||
1888                             test_bit(R5_InJournal, &head_sh->dev[i].flags))
1889                                 xor_srcs[count++] = dev->page;
1890                 }
1891         } else {
1892                 xor_dest = sh->dev[pd_idx].page;
1893                 for (i = disks; i--; ) {
1894                         struct r5dev *dev = &sh->dev[i];
1895                         if (i != pd_idx)
1896                                 xor_srcs[count++] = dev->page;
1897                 }
1898         }
1899
1900         /* 1/ if we prexor'd then the dest is reused as a source
1901          * 2/ if we did not prexor then we are redoing the parity
1902          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1903          * for the synchronous xor case
1904          */
1905         last_stripe = !head_sh->batch_head ||
1906                 list_first_entry(&sh->batch_list,
1907                                  struct stripe_head, batch_list) == head_sh;
1908         if (last_stripe) {
1909                 flags = ASYNC_TX_ACK |
1910                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1911
1912                 atomic_inc(&head_sh->count);
1913                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
1914                                   to_addr_conv(sh, percpu, j));
1915         } else {
1916                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
1917                 init_async_submit(&submit, flags, tx, NULL, NULL,
1918                                   to_addr_conv(sh, percpu, j));
1919         }
1920
1921         if (unlikely(count == 1))
1922                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1923         else
1924                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1925         if (!last_stripe) {
1926                 j++;
1927                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1928                                       batch_list);
1929                 goto again;
1930         }
1931 }
1932
1933 static void
1934 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1935                      struct dma_async_tx_descriptor *tx)
1936 {
1937         struct async_submit_ctl submit;
1938         struct page **blocks;
1939         int count, i, j = 0;
1940         struct stripe_head *head_sh = sh;
1941         int last_stripe;
1942         int synflags;
1943         unsigned long txflags;
1944
1945         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1946
1947         for (i = 0; i < sh->disks; i++) {
1948                 if (sh->pd_idx == i || sh->qd_idx == i)
1949                         continue;
1950                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1951                         break;
1952         }
1953         if (i >= sh->disks) {
1954                 atomic_inc(&sh->count);
1955                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
1956                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
1957                 ops_complete_reconstruct(sh);
1958                 return;
1959         }
1960
1961 again:
1962         blocks = to_addr_page(percpu, j);
1963
1964         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1965                 synflags = SYNDROME_SRC_WRITTEN;
1966                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
1967         } else {
1968                 synflags = SYNDROME_SRC_ALL;
1969                 txflags = ASYNC_TX_ACK;
1970         }
1971
1972         count = set_syndrome_sources(blocks, sh, synflags);
1973         last_stripe = !head_sh->batch_head ||
1974                 list_first_entry(&sh->batch_list,
1975                                  struct stripe_head, batch_list) == head_sh;
1976
1977         if (last_stripe) {
1978                 atomic_inc(&head_sh->count);
1979                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
1980                                   head_sh, to_addr_conv(sh, percpu, j));
1981         } else
1982                 init_async_submit(&submit, 0, tx, NULL, NULL,
1983                                   to_addr_conv(sh, percpu, j));
1984         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1985         if (!last_stripe) {
1986                 j++;
1987                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1988                                       batch_list);
1989                 goto again;
1990         }
1991 }
1992
1993 static void ops_complete_check(void *stripe_head_ref)
1994 {
1995         struct stripe_head *sh = stripe_head_ref;
1996
1997         pr_debug("%s: stripe %llu\n", __func__,
1998                 (unsigned long long)sh->sector);
1999
2000         sh->check_state = check_state_check_result;
2001         set_bit(STRIPE_HANDLE, &sh->state);
2002         raid5_release_stripe(sh);
2003 }
2004
2005 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2006 {
2007         int disks = sh->disks;
2008         int pd_idx = sh->pd_idx;
2009         int qd_idx = sh->qd_idx;
2010         struct page *xor_dest;
2011         struct page **xor_srcs = to_addr_page(percpu, 0);
2012         struct dma_async_tx_descriptor *tx;
2013         struct async_submit_ctl submit;
2014         int count;
2015         int i;
2016
2017         pr_debug("%s: stripe %llu\n", __func__,
2018                 (unsigned long long)sh->sector);
2019
2020         BUG_ON(sh->batch_head);
2021         count = 0;
2022         xor_dest = sh->dev[pd_idx].page;
2023         xor_srcs[count++] = xor_dest;
2024         for (i = disks; i--; ) {
2025                 if (i == pd_idx || i == qd_idx)
2026                         continue;
2027                 xor_srcs[count++] = sh->dev[i].page;
2028         }
2029
2030         init_async_submit(&submit, 0, NULL, NULL, NULL,
2031                           to_addr_conv(sh, percpu, 0));
2032         tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
2033                            &sh->ops.zero_sum_result, &submit);
2034
2035         atomic_inc(&sh->count);
2036         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2037         tx = async_trigger_callback(&submit);
2038 }
2039
2040 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2041 {
2042         struct page **srcs = to_addr_page(percpu, 0);
2043         struct async_submit_ctl submit;
2044         int count;
2045
2046         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2047                 (unsigned long long)sh->sector, checkp);
2048
2049         BUG_ON(sh->batch_head);
2050         count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
2051         if (!checkp)
2052                 srcs[count] = NULL;
2053
2054         atomic_inc(&sh->count);
2055         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2056                           sh, to_addr_conv(sh, percpu, 0));
2057         async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
2058                            &sh->ops.zero_sum_result, percpu->spare_page, &submit);
2059 }
2060
2061 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2062 {
2063         int overlap_clear = 0, i, disks = sh->disks;
2064         struct dma_async_tx_descriptor *tx = NULL;
2065         struct r5conf *conf = sh->raid_conf;
2066         int level = conf->level;
2067         struct raid5_percpu *percpu;
2068         unsigned long cpu;
2069
2070         cpu = get_cpu();
2071         percpu = per_cpu_ptr(conf->percpu, cpu);
2072         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2073                 ops_run_biofill(sh);
2074                 overlap_clear++;
2075         }
2076
2077         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2078                 if (level < 6)
2079                         tx = ops_run_compute5(sh, percpu);
2080                 else {
2081                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2082                                 tx = ops_run_compute6_1(sh, percpu);
2083                         else
2084                                 tx = ops_run_compute6_2(sh, percpu);
2085                 }
2086                 /* terminate the chain if reconstruct is not set to be run */
2087                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2088                         async_tx_ack(tx);
2089         }
2090
2091         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2092                 if (level < 6)
2093                         tx = ops_run_prexor5(sh, percpu, tx);
2094                 else
2095                         tx = ops_run_prexor6(sh, percpu, tx);
2096         }
2097
2098         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2099                 tx = ops_run_partial_parity(sh, percpu, tx);
2100
2101         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2102                 tx = ops_run_biodrain(sh, tx);
2103                 overlap_clear++;
2104         }
2105
2106         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2107                 if (level < 6)
2108                         ops_run_reconstruct5(sh, percpu, tx);
2109                 else
2110                         ops_run_reconstruct6(sh, percpu, tx);
2111         }
2112
2113         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2114                 if (sh->check_state == check_state_run)
2115                         ops_run_check_p(sh, percpu);
2116                 else if (sh->check_state == check_state_run_q)
2117                         ops_run_check_pq(sh, percpu, 0);
2118                 else if (sh->check_state == check_state_run_pq)
2119                         ops_run_check_pq(sh, percpu, 1);
2120                 else
2121                         BUG();
2122         }
2123
2124         if (overlap_clear && !sh->batch_head)
2125                 for (i = disks; i--; ) {
2126                         struct r5dev *dev = &sh->dev[i];
2127                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2128                                 wake_up(&sh->raid_conf->wait_for_overlap);
2129                 }
2130         put_cpu();
2131 }
2132
2133 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2134 {
2135         if (sh->ppl_page)
2136                 __free_page(sh->ppl_page);
2137         kmem_cache_free(sc, sh);
2138 }
2139
2140 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2141         int disks, struct r5conf *conf)
2142 {
2143         struct stripe_head *sh;
2144         int i;
2145
2146         sh = kmem_cache_zalloc(sc, gfp);
2147         if (sh) {
2148                 spin_lock_init(&sh->stripe_lock);
2149                 spin_lock_init(&sh->batch_lock);
2150                 INIT_LIST_HEAD(&sh->batch_list);
2151                 INIT_LIST_HEAD(&sh->lru);
2152                 INIT_LIST_HEAD(&sh->r5c);
2153                 INIT_LIST_HEAD(&sh->log_list);
2154                 atomic_set(&sh->count, 1);
2155                 sh->raid_conf = conf;
2156                 sh->log_start = MaxSector;
2157                 for (i = 0; i < disks; i++) {
2158                         struct r5dev *dev = &sh->dev[i];
2159
2160                         bio_init(&dev->req, &dev->vec, 1);
2161                         bio_init(&dev->rreq, &dev->rvec, 1);
2162                 }
2163
2164                 if (raid5_has_ppl(conf)) {
2165                         sh->ppl_page = alloc_page(gfp);
2166                         if (!sh->ppl_page) {
2167                                 free_stripe(sc, sh);
2168                                 sh = NULL;
2169                         }
2170                 }
2171         }
2172         return sh;
2173 }
2174 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2175 {
2176         struct stripe_head *sh;
2177
2178         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2179         if (!sh)
2180                 return 0;
2181
2182         if (grow_buffers(sh, gfp)) {
2183                 shrink_buffers(sh);
2184                 free_stripe(conf->slab_cache, sh);
2185                 return 0;
2186         }
2187         sh->hash_lock_index =
2188                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2189         /* we just created an active stripe so... */
2190         atomic_inc(&conf->active_stripes);
2191
2192         raid5_release_stripe(sh);
2193         conf->max_nr_stripes++;
2194         return 1;
2195 }
2196
2197 static int grow_stripes(struct r5conf *conf, int num)
2198 {
2199         struct kmem_cache *sc;
2200         size_t namelen = sizeof(conf->cache_name[0]);
2201         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2202
2203         if (conf->mddev->gendisk)
2204                 snprintf(conf->cache_name[0], namelen,
2205                         "raid%d-%s", conf->level, mdname(conf->mddev));
2206         else
2207                 snprintf(conf->cache_name[0], namelen,
2208                         "raid%d-%p", conf->level, conf->mddev);
2209         snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2210
2211         conf->active_name = 0;
2212         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2213                                sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2214                                0, 0, NULL);
2215         if (!sc)
2216                 return 1;
2217         conf->slab_cache = sc;
2218         conf->pool_size = devs;
2219         while (num--)
2220                 if (!grow_one_stripe(conf, GFP_KERNEL))
2221                         return 1;
2222
2223         return 0;
2224 }
2225
2226 /**
2227  * scribble_len - return the required size of the scribble region
2228  * @num - total number of disks in the array
2229  *
2230  * The size must be enough to contain:
2231  * 1/ a struct page pointer for each device in the array +2
2232  * 2/ room to convert each entry in (1) to its corresponding dma
2233  *    (dma_map_page()) or page (page_address()) address.
2234  *
2235  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2236  * calculate over all devices (not just the data blocks), using zeros in place
2237  * of the P and Q blocks.
2238  */
2239 static struct flex_array *scribble_alloc(int num, int cnt, gfp_t flags)
2240 {
2241         struct flex_array *ret;
2242         size_t len;
2243
2244         len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);
2245         ret = flex_array_alloc(len, cnt, flags);
2246         if (!ret)
2247                 return NULL;
2248         /* always prealloc all elements, so no locking is required */
2249         if (flex_array_prealloc(ret, 0, cnt, flags)) {
2250                 flex_array_free(ret);
2251                 return NULL;
2252         }
2253         return ret;
2254 }
2255
2256 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2257 {
2258         unsigned long cpu;
2259         int err = 0;
2260
2261         /*
2262          * Never shrink. And mddev_suspend() could deadlock if this is called
2263          * from raid5d. In that case, scribble_disks and scribble_sectors
2264          * should equal to new_disks and new_sectors
2265          */
2266         if (conf->scribble_disks >= new_disks &&
2267             conf->scribble_sectors >= new_sectors)
2268                 return 0;
2269         mddev_suspend(conf->mddev);
2270         get_online_cpus();
2271         for_each_present_cpu(cpu) {
2272                 struct raid5_percpu *percpu;
2273                 struct flex_array *scribble;
2274
2275                 percpu = per_cpu_ptr(conf->percpu, cpu);
2276                 scribble = scribble_alloc(new_disks,
2277                                           new_sectors / STRIPE_SECTORS,
2278                                           GFP_NOIO);
2279
2280                 if (scribble) {
2281                         flex_array_free(percpu->scribble);
2282                         percpu->scribble = scribble;
2283                 } else {
2284                         err = -ENOMEM;
2285                         break;
2286                 }
2287         }
2288         put_online_cpus();
2289         mddev_resume(conf->mddev);
2290         if (!err) {
2291                 conf->scribble_disks = new_disks;
2292                 conf->scribble_sectors = new_sectors;
2293         }
2294         return err;
2295 }
2296
2297 static int resize_stripes(struct r5conf *conf, int newsize)
2298 {
2299         /* Make all the stripes able to hold 'newsize' devices.
2300          * New slots in each stripe get 'page' set to a new page.
2301          *
2302          * This happens in stages:
2303          * 1/ create a new kmem_cache and allocate the required number of
2304          *    stripe_heads.
2305          * 2/ gather all the old stripe_heads and transfer the pages across
2306          *    to the new stripe_heads.  This will have the side effect of
2307          *    freezing the array as once all stripe_heads have been collected,
2308          *    no IO will be possible.  Old stripe heads are freed once their
2309          *    pages have been transferred over, and the old kmem_cache is
2310          *    freed when all stripes are done.
2311          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2312          *    we simple return a failure status - no need to clean anything up.
2313          * 4/ allocate new pages for the new slots in the new stripe_heads.
2314          *    If this fails, we don't bother trying the shrink the
2315          *    stripe_heads down again, we just leave them as they are.
2316          *    As each stripe_head is processed the new one is released into
2317          *    active service.
2318          *
2319          * Once step2 is started, we cannot afford to wait for a write,
2320          * so we use GFP_NOIO allocations.
2321          */
2322         struct stripe_head *osh, *nsh;
2323         LIST_HEAD(newstripes);
2324         struct disk_info *ndisks;
2325         int err = 0;
2326         struct kmem_cache *sc;
2327         int i;
2328         int hash, cnt;
2329
2330         md_allow_write(conf->mddev);
2331
2332         /* Step 1 */
2333         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2334                                sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2335                                0, 0, NULL);
2336         if (!sc)
2337                 return -ENOMEM;
2338
2339         /* Need to ensure auto-resizing doesn't interfere */
2340         mutex_lock(&conf->cache_size_mutex);
2341
2342         for (i = conf->max_nr_stripes; i; i--) {
2343                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2344                 if (!nsh)
2345                         break;
2346
2347                 list_add(&nsh->lru, &newstripes);
2348         }
2349         if (i) {
2350                 /* didn't get enough, give up */
2351                 while (!list_empty(&newstripes)) {
2352                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2353                         list_del(&nsh->lru);
2354                         free_stripe(sc, nsh);
2355                 }
2356                 kmem_cache_destroy(sc);
2357                 mutex_unlock(&conf->cache_size_mutex);
2358                 return -ENOMEM;
2359         }
2360         /* Step 2 - Must use GFP_NOIO now.
2361          * OK, we have enough stripes, start collecting inactive
2362          * stripes and copying them over
2363          */
2364         hash = 0;
2365         cnt = 0;
2366         list_for_each_entry(nsh, &newstripes, lru) {
2367                 lock_device_hash_lock(conf, hash);
2368                 wait_event_cmd(conf->wait_for_stripe,
2369                                     !list_empty(conf->inactive_list + hash),
2370                                     unlock_device_hash_lock(conf, hash),
2371                                     lock_device_hash_lock(conf, hash));
2372                 osh = get_free_stripe(conf, hash);
2373                 unlock_device_hash_lock(conf, hash);
2374
2375                 for(i=0; i<conf->pool_size; i++) {
2376                         nsh->dev[i].page = osh->dev[i].page;
2377                         nsh->dev[i].orig_page = osh->dev[i].page;
2378                 }
2379                 nsh->hash_lock_index = hash;
2380                 free_stripe(conf->slab_cache, osh);
2381                 cnt++;
2382                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2383                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2384                         hash++;
2385                         cnt = 0;
2386                 }
2387         }
2388         kmem_cache_destroy(conf->slab_cache);
2389
2390         /* Step 3.
2391          * At this point, we are holding all the stripes so the array
2392          * is completely stalled, so now is a good time to resize
2393          * conf->disks and the scribble region
2394          */
2395         ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
2396         if (ndisks) {
2397                 for (i = 0; i < conf->pool_size; i++)
2398                         ndisks[i] = conf->disks[i];
2399
2400                 for (i = conf->pool_size; i < newsize; i++) {
2401                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2402                         if (!ndisks[i].extra_page)
2403                                 err = -ENOMEM;
2404                 }
2405
2406                 if (err) {
2407                         for (i = conf->pool_size; i < newsize; i++)
2408                                 if (ndisks[i].extra_page)
2409                                         put_page(ndisks[i].extra_page);
2410                         kfree(ndisks);
2411                 } else {
2412                         kfree(conf->disks);
2413                         conf->disks = ndisks;
2414                 }
2415         } else
2416                 err = -ENOMEM;
2417
2418         conf->slab_cache = sc;
2419         conf->active_name = 1-conf->active_name;
2420
2421         /* Step 4, return new stripes to service */
2422         while(!list_empty(&newstripes)) {
2423                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2424                 list_del_init(&nsh->lru);
2425
2426                 for (i=conf->raid_disks; i < newsize; i++)
2427                         if (nsh->dev[i].page == NULL) {
2428                                 struct page *p = alloc_page(GFP_NOIO);
2429                                 nsh->dev[i].page = p;
2430                                 nsh->dev[i].orig_page = p;
2431                                 if (!p)
2432                                         err = -ENOMEM;
2433                         }
2434                 raid5_release_stripe(nsh);
2435         }
2436         /* critical section pass, GFP_NOIO no longer needed */
2437
2438         if (!err)
2439                 conf->pool_size = newsize;
2440         mutex_unlock(&conf->cache_size_mutex);
2441
2442         return err;
2443 }
2444
2445 static int drop_one_stripe(struct r5conf *conf)
2446 {
2447         struct stripe_head *sh;
2448         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2449
2450         spin_lock_irq(conf->hash_locks + hash);
2451         sh = get_free_stripe(conf, hash);
2452         spin_unlock_irq(conf->hash_locks + hash);
2453         if (!sh)
2454                 return 0;
2455         BUG_ON(atomic_read(&sh->count));
2456         shrink_buffers(sh);
2457         free_stripe(conf->slab_cache, sh);
2458         atomic_dec(&conf->active_stripes);
2459         conf->max_nr_stripes--;
2460         return 1;
2461 }
2462
2463 static void shrink_stripes(struct r5conf *conf)
2464 {
2465         while (conf->max_nr_stripes &&
2466                drop_one_stripe(conf))
2467                 ;
2468
2469         kmem_cache_destroy(conf->slab_cache);
2470         conf->slab_cache = NULL;
2471 }
2472
2473 static void raid5_end_read_request(struct bio * bi)
2474 {
2475         struct stripe_head *sh = bi->bi_private;
2476         struct r5conf *conf = sh->raid_conf;
2477         int disks = sh->disks, i;
2478         char b[BDEVNAME_SIZE];
2479         struct md_rdev *rdev = NULL;
2480         sector_t s;
2481
2482         for (i=0 ; i<disks; i++)
2483                 if (bi == &sh->dev[i].req)
2484                         break;
2485
2486         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2487                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2488                 bi->bi_status);
2489         if (i == disks) {
2490                 bio_reset(bi);
2491                 BUG();
2492                 return;
2493         }
2494         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2495                 /* If replacement finished while this request was outstanding,
2496                  * 'replacement' might be NULL already.
2497                  * In that case it moved down to 'rdev'.
2498                  * rdev is not removed until all requests are finished.
2499                  */
2500                 rdev = conf->disks[i].replacement;
2501         if (!rdev)
2502                 rdev = conf->disks[i].rdev;
2503
2504         if (use_new_offset(conf, sh))
2505                 s = sh->sector + rdev->new_data_offset;
2506         else
2507                 s = sh->sector + rdev->data_offset;
2508         if (!bi->bi_status) {
2509                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2510                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2511                         /* Note that this cannot happen on a
2512                          * replacement device.  We just fail those on
2513                          * any error
2514                          */
2515                         pr_info_ratelimited(
2516                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %s)\n",
2517                                 mdname(conf->mddev), STRIPE_SECTORS,
2518                                 (unsigned long long)s,
2519                                 bdevname(rdev->bdev, b));
2520                         atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
2521                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2522                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2523                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2524                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2525
2526                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2527                         /*
2528                          * end read for a page in journal, this
2529                          * must be preparing for prexor in rmw
2530                          */
2531                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2532
2533                 if (atomic_read(&rdev->read_errors))
2534                         atomic_set(&rdev->read_errors, 0);
2535         } else {
2536                 const char *bdn = bdevname(rdev->bdev, b);
2537                 int retry = 0;
2538                 int set_bad = 0;
2539
2540                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2541                 if (!(bi->bi_status == BLK_STS_PROTECTION))
2542                         atomic_inc(&rdev->read_errors);
2543                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2544                         pr_warn_ratelimited(
2545                                 "md/raid:%s: read error on replacement device (sector %llu on %s).\n",
2546                                 mdname(conf->mddev),
2547                                 (unsigned long long)s,
2548                                 bdn);
2549                 else if (conf->mddev->degraded >= conf->max_degraded) {
2550                         set_bad = 1;
2551                         pr_warn_ratelimited(
2552                                 "md/raid:%s: read error not correctable (sector %llu on %s).\n",
2553                                 mdname(conf->mddev),
2554                                 (unsigned long long)s,
2555                                 bdn);
2556                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2557                         /* Oh, no!!! */
2558                         set_bad = 1;
2559                         pr_warn_ratelimited(
2560                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %s).\n",
2561                                 mdname(conf->mddev),
2562                                 (unsigned long long)s,
2563                                 bdn);
2564                 } else if (atomic_read(&rdev->read_errors)
2565                          > conf->max_nr_stripes)
2566                         pr_warn("md/raid:%s: Too many read errors, failing device %s.\n",
2567                                mdname(conf->mddev), bdn);
2568                 else
2569                         retry = 1;
2570                 if (set_bad && test_bit(In_sync, &rdev->flags)
2571                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2572                         retry = 1;
2573                 if (retry)
2574                         if (sh->qd_idx >= 0 && sh->pd_idx == i)
2575                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2576                         else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2577                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2578                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2579                         } else
2580                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2581                 else {
2582                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2583                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2584                         if (!(set_bad
2585                               && test_bit(In_sync, &rdev->flags)
2586                               && rdev_set_badblocks(
2587                                       rdev, sh->sector, STRIPE_SECTORS, 0)))
2588                                 md_error(conf->mddev, rdev);
2589                 }
2590         }
2591         rdev_dec_pending(rdev, conf->mddev);
2592         bio_reset(bi);
2593         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2594         set_bit(STRIPE_HANDLE, &sh->state);
2595         raid5_release_stripe(sh);
2596 }
2597
2598 static void raid5_end_write_request(struct bio *bi)
2599 {
2600         struct stripe_head *sh = bi->bi_private;
2601         struct r5conf *conf = sh->raid_conf;
2602         int disks = sh->disks, i;
2603         struct md_rdev *uninitialized_var(rdev);
2604         sector_t first_bad;
2605         int bad_sectors;
2606         int replacement = 0;
2607
2608         for (i = 0 ; i < disks; i++) {
2609                 if (bi == &sh->dev[i].req) {
2610                         rdev = conf->disks[i].rdev;
2611                         break;
2612                 }
2613                 if (bi == &sh->dev[i].rreq) {
2614                         rdev = conf->disks[i].replacement;
2615                         if (rdev)
2616                                 replacement = 1;
2617                         else
2618                                 /* rdev was removed and 'replacement'
2619                                  * replaced it.  rdev is not removed
2620                                  * until all requests are finished.
2621                                  */
2622                                 rdev = conf->disks[i].rdev;
2623                         break;
2624                 }
2625         }
2626         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2627                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2628                 bi->bi_status);
2629         if (i == disks) {
2630                 bio_reset(bi);
2631                 BUG();
2632                 return;
2633         }
2634
2635         if (replacement) {
2636                 if (bi->bi_status)
2637                         md_error(conf->mddev, rdev);
2638                 else if (is_badblock(rdev, sh->sector,
2639                                      STRIPE_SECTORS,
2640                                      &first_bad, &bad_sectors))
2641                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2642         } else {
2643                 if (bi->bi_status) {
2644                         set_bit(STRIPE_DEGRADED, &sh->state);
2645                         set_bit(WriteErrorSeen, &rdev->flags);
2646                         set_bit(R5_WriteError, &sh->dev[i].flags);
2647                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2648                                 set_bit(MD_RECOVERY_NEEDED,
2649                                         &rdev->mddev->recovery);
2650                 } else if (is_badblock(rdev, sh->sector,
2651                                        STRIPE_SECTORS,
2652                                        &first_bad, &bad_sectors)) {
2653                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2654                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2655                                 /* That was a successful write so make
2656                                  * sure it looks like we already did
2657                                  * a re-write.
2658                                  */
2659                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2660                 }
2661         }
2662         rdev_dec_pending(rdev, conf->mddev);
2663
2664         if (sh->batch_head && bi->bi_status && !replacement)
2665                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2666
2667         bio_reset(bi);
2668         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2669                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2670         set_bit(STRIPE_HANDLE, &sh->state);
2671         raid5_release_stripe(sh);
2672
2673         if (sh->batch_head && sh != sh->batch_head)
2674                 raid5_release_stripe(sh->batch_head);
2675 }
2676
2677 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2678 {
2679         char b[BDEVNAME_SIZE];
2680         struct r5conf *conf = mddev->private;
2681         unsigned long flags;
2682         pr_debug("raid456: error called\n");
2683
2684         spin_lock_irqsave(&conf->device_lock, flags);
2685         set_bit(Faulty, &rdev->flags);
2686         clear_bit(In_sync, &rdev->flags);
2687         mddev->degraded = raid5_calc_degraded(conf);
2688         spin_unlock_irqrestore(&conf->device_lock, flags);
2689         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2690
2691         set_bit(Blocked, &rdev->flags);
2692         set_mask_bits(&mddev->sb_flags, 0,
2693                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2694         pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
2695                 "md/raid:%s: Operation continuing on %d devices.\n",
2696                 mdname(mddev),
2697                 bdevname(rdev->bdev, b),
2698                 mdname(mddev),
2699                 conf->raid_disks - mddev->degraded);
2700         r5c_update_on_rdev_error(mddev, rdev);
2701 }
2702
2703 /*
2704  * Input: a 'big' sector number,
2705  * Output: index of the data and parity disk, and the sector # in them.
2706  */
2707 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2708                               int previous, int *dd_idx,
2709                               struct stripe_head *sh)
2710 {
2711         sector_t stripe, stripe2;
2712         sector_t chunk_number;
2713         unsigned int chunk_offset;
2714         int pd_idx, qd_idx;
2715         int ddf_layout = 0;
2716         sector_t new_sector;
2717         int algorithm = previous ? conf->prev_algo
2718                                  : conf->algorithm;
2719         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2720                                          : conf->chunk_sectors;
2721         int raid_disks = previous ? conf->previous_raid_disks
2722                                   : conf->raid_disks;
2723         int data_disks = raid_disks - conf->max_degraded;
2724
2725         /* First compute the information on this sector */
2726
2727         /*
2728          * Compute the chunk number and the sector offset inside the chunk
2729          */
2730         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2731         chunk_number = r_sector;
2732
2733         /*
2734          * Compute the stripe number
2735          */
2736         stripe = chunk_number;
2737         *dd_idx = sector_div(stripe, data_disks);
2738         stripe2 = stripe;
2739         /*
2740          * Select the parity disk based on the user selected algorithm.
2741          */
2742         pd_idx = qd_idx = -1;
2743         switch(conf->level) {
2744         case 4:
2745                 pd_idx = data_disks;
2746                 break;
2747         case 5:
2748                 switch (algorithm) {
2749                 case ALGORITHM_LEFT_ASYMMETRIC:
2750                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2751                         if (*dd_idx >= pd_idx)
2752                                 (*dd_idx)++;
2753                         break;
2754                 case ALGORITHM_RIGHT_ASYMMETRIC:
2755                         pd_idx = sector_div(stripe2, raid_disks);
2756                         if (*dd_idx >= pd_idx)
2757                                 (*dd_idx)++;
2758                         break;
2759                 case ALGORITHM_LEFT_SYMMETRIC:
2760                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2761                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2762                         break;
2763                 case ALGORITHM_RIGHT_SYMMETRIC:
2764                         pd_idx = sector_div(stripe2, raid_disks);
2765                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2766                         break;
2767                 case ALGORITHM_PARITY_0:
2768                         pd_idx = 0;
2769                         (*dd_idx)++;
2770                         break;
2771                 case ALGORITHM_PARITY_N:
2772                         pd_idx = data_disks;
2773                         break;
2774                 default:
2775                         BUG();
2776                 }
2777                 break;
2778         case 6:
2779
2780                 switch (algorithm) {
2781                 case ALGORITHM_LEFT_ASYMMETRIC:
2782                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2783                         qd_idx = pd_idx + 1;
2784                         if (pd_idx == raid_disks-1) {
2785                                 (*dd_idx)++;    /* Q D D D P */
2786                                 qd_idx = 0;
2787                         } else if (*dd_idx >= pd_idx)
2788                                 (*dd_idx) += 2; /* D D P Q D */
2789                         break;
2790                 case ALGORITHM_RIGHT_ASYMMETRIC:
2791                         pd_idx = sector_div(stripe2, raid_disks);
2792                         qd_idx = pd_idx + 1;
2793                         if (pd_idx == raid_disks-1) {
2794                                 (*dd_idx)++;    /* Q D D D P */
2795                                 qd_idx = 0;
2796                         } else if (*dd_idx >= pd_idx)
2797                                 (*dd_idx) += 2; /* D D P Q D */
2798                         break;
2799                 case ALGORITHM_LEFT_SYMMETRIC:
2800                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2801                         qd_idx = (pd_idx + 1) % raid_disks;
2802                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2803                         break;
2804                 case ALGORITHM_RIGHT_SYMMETRIC:
2805                         pd_idx = sector_div(stripe2, raid_disks);
2806                         qd_idx = (pd_idx + 1) % raid_disks;
2807                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2808                         break;
2809
2810                 case ALGORITHM_PARITY_0:
2811                         pd_idx = 0;
2812                         qd_idx = 1;
2813                         (*dd_idx) += 2;
2814                         break;
2815                 case ALGORITHM_PARITY_N:
2816                         pd_idx = data_disks;
2817                         qd_idx = data_disks + 1;
2818                         break;
2819
2820                 case ALGORITHM_ROTATING_ZERO_RESTART:
2821                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
2822                          * of blocks for computing Q is different.
2823                          */
2824                         pd_idx = sector_div(stripe2, raid_disks);
2825                         qd_idx = pd_idx + 1;
2826                         if (pd_idx == raid_disks-1) {
2827                                 (*dd_idx)++;    /* Q D D D P */
2828                                 qd_idx = 0;
2829                         } else if (*dd_idx >= pd_idx)
2830                                 (*dd_idx) += 2; /* D D P Q D */
2831                         ddf_layout = 1;
2832                         break;
2833
2834                 case ALGORITHM_ROTATING_N_RESTART:
2835                         /* Same a left_asymmetric, by first stripe is
2836                          * D D D P Q  rather than
2837                          * Q D D D P
2838                          */
2839                         stripe2 += 1;
2840                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2841                         qd_idx = pd_idx + 1;
2842                         if (pd_idx == raid_disks-1) {
2843                                 (*dd_idx)++;    /* Q D D D P */
2844                                 qd_idx = 0;
2845                         } else if (*dd_idx >= pd_idx)
2846                                 (*dd_idx) += 2; /* D D P Q D */
2847                         ddf_layout = 1;
2848                         break;
2849
2850                 case ALGORITHM_ROTATING_N_CONTINUE:
2851                         /* Same as left_symmetric but Q is before P */
2852                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2853                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2854                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2855                         ddf_layout = 1;
2856                         break;
2857
2858                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2859                         /* RAID5 left_asymmetric, with Q on last device */
2860                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2861                         if (*dd_idx >= pd_idx)
2862                                 (*dd_idx)++;
2863                         qd_idx = raid_disks - 1;
2864                         break;
2865
2866                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2867                         pd_idx = sector_div(stripe2, raid_disks-1);
2868                         if (*dd_idx >= pd_idx)
2869                                 (*dd_idx)++;
2870                         qd_idx = raid_disks - 1;
2871                         break;
2872
2873                 case ALGORITHM_LEFT_SYMMETRIC_6:
2874                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2875                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2876                         qd_idx = raid_disks - 1;
2877                         break;
2878
2879                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2880                         pd_idx = sector_div(stripe2, raid_disks-1);
2881                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2882                         qd_idx = raid_disks - 1;
2883                         break;
2884
2885                 case ALGORITHM_PARITY_0_6:
2886                         pd_idx = 0;
2887                         (*dd_idx)++;
2888                         qd_idx = raid_disks - 1;
2889                         break;
2890
2891                 default:
2892                         BUG();
2893                 }
2894                 break;
2895         }
2896
2897         if (sh) {
2898                 sh->pd_idx = pd_idx;
2899                 sh->qd_idx = qd_idx;
2900                 sh->ddf_layout = ddf_layout;
2901         }
2902         /*
2903          * Finally, compute the new sector number
2904          */
2905         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2906         return new_sector;
2907 }
2908
2909 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
2910 {
2911         struct r5conf *conf = sh->raid_conf;
2912         int raid_disks = sh->disks;
2913         int data_disks = raid_disks - conf->max_degraded;
2914         sector_t new_sector = sh->sector, check;
2915         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2916                                          : conf->chunk_sectors;
2917         int algorithm = previous ? conf->prev_algo
2918                                  : conf->algorithm;
2919         sector_t stripe;
2920         int chunk_offset;
2921         sector_t chunk_number;
2922         int dummy1, dd_idx = i;
2923         sector_t r_sector;
2924         struct stripe_head sh2;
2925
2926         chunk_offset = sector_div(new_sector, sectors_per_chunk);
2927         stripe = new_sector;
2928
2929         if (i == sh->pd_idx)
2930                 return 0;
2931         switch(conf->level) {
2932         case 4: break;
2933         case 5:
2934                 switch (algorithm) {
2935                 case ALGORITHM_LEFT_ASYMMETRIC:
2936                 case ALGORITHM_RIGHT_ASYMMETRIC:
2937                         if (i > sh->pd_idx)
2938                                 i--;
2939                         break;
2940                 case ALGORITHM_LEFT_SYMMETRIC:
2941                 case ALGORITHM_RIGHT_SYMMETRIC:
2942                         if (i < sh->pd_idx)
2943                                 i += raid_disks;
2944                         i -= (sh->pd_idx + 1);
2945                         break;
2946                 case ALGORITHM_PARITY_0:
2947                         i -= 1;
2948                         break;
2949                 case ALGORITHM_PARITY_N:
2950                         break;
2951                 default:
2952                         BUG();
2953                 }
2954                 break;
2955         case 6:
2956                 if (i == sh->qd_idx)
2957                         return 0; /* It is the Q disk */
2958                 switch (algorithm) {
2959                 case ALGORITHM_LEFT_ASYMMETRIC:
2960                 case ALGORITHM_RIGHT_ASYMMETRIC:
2961                 case ALGORITHM_ROTATING_ZERO_RESTART:
2962                 case ALGORITHM_ROTATING_N_RESTART:
2963                         if (sh->pd_idx == raid_disks-1)
2964                                 i--;    /* Q D D D P */
2965                         else if (i > sh->pd_idx)
2966                                 i -= 2; /* D D P Q D */
2967                         break;
2968                 case ALGORITHM_LEFT_SYMMETRIC:
2969                 case ALGORITHM_RIGHT_SYMMETRIC:
2970                         if (sh->pd_idx == raid_disks-1)
2971                                 i--; /* Q D D D P */
2972                         else {
2973                                 /* D D P Q D */
2974                                 if (i < sh->pd_idx)
2975                                         i += raid_disks;
2976                                 i -= (sh->pd_idx + 2);
2977                         }
2978                         break;
2979                 case ALGORITHM_PARITY_0:
2980                         i -= 2;
2981                         break;
2982                 case ALGORITHM_PARITY_N:
2983                         break;
2984                 case ALGORITHM_ROTATING_N_CONTINUE:
2985                         /* Like left_symmetric, but P is before Q */
2986                         if (sh->pd_idx == 0)
2987                                 i--;    /* P D D D Q */
2988                         else {
2989                                 /* D D Q P D */
2990                                 if (i < sh->pd_idx)
2991                                         i += raid_disks;
2992                                 i -= (sh->pd_idx + 1);
2993                         }
2994                         break;
2995                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2996                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2997                         if (i > sh->pd_idx)
2998                                 i--;
2999                         break;
3000                 case ALGORITHM_LEFT_SYMMETRIC_6:
3001                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3002                         if (i < sh->pd_idx)
3003                                 i += data_disks + 1;
3004                         i -= (sh->pd_idx + 1);
3005                         break;
3006                 case ALGORITHM_PARITY_0_6:
3007                         i -= 1;
3008                         break;
3009                 default:
3010                         BUG();
3011                 }
3012                 break;
3013         }
3014
3015         chunk_number = stripe * data_disks + i;
3016         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3017
3018         check = raid5_compute_sector(conf, r_sector,
3019                                      previous, &dummy1, &sh2);
3020         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3021                 || sh2.qd_idx != sh->qd_idx) {
3022                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3023                         mdname(conf->mddev));
3024                 return 0;
3025         }
3026         return r_sector;
3027 }
3028
3029 /*
3030  * There are cases where we want handle_stripe_dirtying() and
3031  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3032  *
3033  * This function checks whether we want to delay the towrite. Specifically,
3034  * we delay the towrite when:
3035  *
3036  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3037  *      stripe has data in journal (for other devices).
3038  *
3039  *      In this case, when reading data for the non-overwrite dev, it is
3040  *      necessary to handle complex rmw of write back cache (prexor with
3041  *      orig_page, and xor with page). To keep read path simple, we would
3042  *      like to flush data in journal to RAID disks first, so complex rmw
3043  *      is handled in the write patch (handle_stripe_dirtying).
3044  *
3045  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3046  *
3047  *      It is important to be able to flush all stripes in raid5-cache.
3048  *      Therefore, we need reserve some space on the journal device for
3049  *      these flushes. If flush operation includes pending writes to the
3050  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3051  *      for the flush out. If we exclude these pending writes from flush
3052  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3053  *      Therefore, excluding pending writes in these cases enables more
3054  *      efficient use of the journal device.
3055  *
3056  *      Note: To make sure the stripe makes progress, we only delay
3057  *      towrite for stripes with data already in journal (injournal > 0).
3058  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3059  *      no_space_stripes list.
3060  *
3061  *   3. during journal failure
3062  *      In journal failure, we try to flush all cached data to raid disks
3063  *      based on data in stripe cache. The array is read-only to upper
3064  *      layers, so we would skip all pending writes.
3065  *
3066  */
3067 static inline bool delay_towrite(struct r5conf *conf,
3068                                  struct r5dev *dev,
3069                                  struct stripe_head_state *s)
3070 {
3071         /* case 1 above */
3072         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3073             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3074                 return true;
3075         /* case 2 above */
3076         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3077             s->injournal > 0)
3078                 return true;
3079         /* case 3 above */
3080         if (s->log_failed && s->injournal)
3081                 return true;
3082         return false;
3083 }
3084
3085 static void
3086 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3087                          int rcw, int expand)
3088 {
3089         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3090         struct r5conf *conf = sh->raid_conf;
3091         int level = conf->level;
3092
3093         if (rcw) {
3094                 /*
3095                  * In some cases, handle_stripe_dirtying initially decided to
3096                  * run rmw and allocates extra page for prexor. However, rcw is
3097                  * cheaper later on. We need to free the extra page now,
3098                  * because we won't be able to do that in ops_complete_prexor().
3099                  */
3100                 r5c_release_extra_page(sh);
3101
3102                 for (i = disks; i--; ) {
3103                         struct r5dev *dev = &sh->dev[i];
3104
3105                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3106                                 set_bit(R5_LOCKED, &dev->flags);
3107                                 set_bit(R5_Wantdrain, &dev->flags);
3108                                 if (!expand)
3109                                         clear_bit(R5_UPTODATE, &dev->flags);
3110                                 s->locked++;
3111                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3112                                 set_bit(R5_LOCKED, &dev->flags);
3113                                 s->locked++;
3114                         }
3115                 }
3116                 /* if we are not expanding this is a proper write request, and
3117                  * there will be bios with new data to be drained into the
3118                  * stripe cache
3119                  */
3120                 if (!expand) {
3121                         if (!s->locked)
3122                                 /* False alarm, nothing to do */
3123                                 return;
3124                         sh->reconstruct_state = reconstruct_state_drain_run;
3125                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3126                 } else
3127                         sh->reconstruct_state = reconstruct_state_run;
3128
3129                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3130
3131                 if (s->locked + conf->max_degraded == disks)
3132                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3133                                 atomic_inc(&conf->pending_full_writes);
3134         } else {
3135                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3136                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3137                 BUG_ON(level == 6 &&
3138                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3139                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3140
3141                 for (i = disks; i--; ) {
3142                         struct r5dev *dev = &sh->dev[i];
3143                         if (i == pd_idx || i == qd_idx)
3144                                 continue;
3145
3146                         if (dev->towrite &&
3147                             (test_bit(R5_UPTODATE, &dev->flags) ||
3148                              test_bit(R5_Wantcompute, &dev->flags))) {
3149                                 set_bit(R5_Wantdrain, &dev->flags);
3150                                 set_bit(R5_LOCKED, &dev->flags);
3151                                 clear_bit(R5_UPTODATE, &dev->flags);
3152                                 s->locked++;
3153                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3154                                 set_bit(R5_LOCKED, &dev->flags);
3155                                 s->locked++;
3156                         }
3157                 }
3158                 if (!s->locked)
3159                         /* False alarm - nothing to do */
3160                         return;
3161                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3162                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3163                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3164                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3165         }
3166
3167         /* keep the parity disk(s) locked while asynchronous operations
3168          * are in flight
3169          */
3170         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3171         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3172         s->locked++;
3173
3174         if (level == 6) {
3175                 int qd_idx = sh->qd_idx;
3176                 struct r5dev *dev = &sh->dev[qd_idx];
3177
3178                 set_bit(R5_LOCKED, &dev->flags);
3179                 clear_bit(R5_UPTODATE, &dev->flags);
3180                 s->locked++;
3181         }
3182
3183         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3184             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3185             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3186             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3187                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3188
3189         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3190                 __func__, (unsigned long long)sh->sector,
3191                 s->locked, s->ops_request);
3192 }
3193
3194 /*
3195  * Each stripe/dev can have one or more bion attached.
3196  * toread/towrite point to the first in a chain.
3197  * The bi_next chain must be in order.
3198  */
3199 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
3200                           int forwrite, int previous)
3201 {
3202         struct bio **bip;
3203         struct r5conf *conf = sh->raid_conf;
3204         int firstwrite=0;
3205
3206         pr_debug("adding bi b#%llu to stripe s#%llu\n",
3207                 (unsigned long long)bi->bi_iter.bi_sector,
3208                 (unsigned long long)sh->sector);
3209
3210         spin_lock_irq(&sh->stripe_lock);
3211         /* Don't allow new IO added to stripes in batch list */
3212         if (sh->batch_head)
3213                 goto overlap;
3214         if (forwrite) {
3215                 bip = &sh->dev[dd_idx].towrite;
3216                 if (*bip == NULL)
3217                         firstwrite = 1;
3218         } else
3219                 bip = &sh->dev[dd_idx].toread;
3220         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3221                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3222                         goto overlap;
3223                 bip = & (*bip)->bi_next;
3224         }
3225         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3226                 goto overlap;
3227
3228         if (forwrite && raid5_has_ppl(conf)) {
3229                 /*
3230                  * With PPL only writes to consecutive data chunks within a
3231                  * stripe are allowed because for a single stripe_head we can
3232                  * only have one PPL entry at a time, which describes one data
3233                  * range. Not really an overlap, but wait_for_overlap can be
3234                  * used to handle this.
3235                  */
3236                 sector_t sector;
3237                 sector_t first = 0;
3238                 sector_t last = 0;
3239                 int count = 0;
3240                 int i;
3241
3242                 for (i = 0; i < sh->disks; i++) {
3243                         if (i != sh->pd_idx &&
3244                             (i == dd_idx || sh->dev[i].towrite)) {
3245                                 sector = sh->dev[i].sector;
3246                                 if (count == 0 || sector < first)
3247                                         first = sector;
3248                                 if (sector > last)
3249                                         last = sector;
3250                                 count++;
3251                         }
3252                 }
3253
3254                 if (first + conf->chunk_sectors * (count - 1) != last)
3255                         goto overlap;
3256         }
3257
3258         if (!forwrite || previous)
3259                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3260
3261         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3262         if (*bip)
3263                 bi->bi_next = *bip;
3264         *bip = bi;
3265         bio_inc_remaining(bi);
3266         md_write_inc(conf->mddev, bi);
3267
3268         if (forwrite) {
3269                 /* check if page is covered */
3270                 sector_t sector = sh->dev[dd_idx].sector;
3271                 for (bi=sh->dev[dd_idx].towrite;
3272                      sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
3273                              bi && bi->bi_iter.bi_sector <= sector;
3274                      bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
3275                         if (bio_end_sector(bi) >= sector)
3276                                 sector = bio_end_sector(bi);
3277                 }
3278                 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
3279                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3280                                 sh->overwrite_disks++;
3281         }
3282
3283         pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
3284                 (unsigned long long)(*bip)->bi_iter.bi_sector,
3285                 (unsigned long long)sh->sector, dd_idx);
3286
3287         if (conf->mddev->bitmap && firstwrite) {
3288                 /* Cannot hold spinlock over bitmap_startwrite,
3289                  * but must ensure this isn't added to a batch until
3290                  * we have added to the bitmap and set bm_seq.
3291                  * So set STRIPE_BITMAP_PENDING to prevent
3292                  * batching.
3293                  * If multiple add_stripe_bio() calls race here they
3294                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3295                  * to complete "bitmap_startwrite" gets to set
3296                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3297                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3298                  * any more.
3299                  */
3300                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3301                 spin_unlock_irq(&sh->stripe_lock);
3302                 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3303                                   STRIPE_SECTORS, 0);
3304                 spin_lock_irq(&sh->stripe_lock);
3305                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3306                 if (!sh->batch_head) {
3307                         sh->bm_seq = conf->seq_flush+1;
3308                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3309                 }
3310         }
3311         spin_unlock_irq(&sh->stripe_lock);
3312
3313         if (stripe_can_batch(sh))
3314                 stripe_add_to_batch_list(conf, sh);
3315         return 1;
3316
3317  overlap:
3318         set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3319         spin_unlock_irq(&sh->stripe_lock);
3320         return 0;
3321 }
3322
3323 static void end_reshape(struct r5conf *conf);
3324
3325 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3326                             struct stripe_head *sh)
3327 {
3328         int sectors_per_chunk =
3329                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3330         int dd_idx;
3331         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3332         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3333
3334         raid5_compute_sector(conf,
3335                              stripe * (disks - conf->max_degraded)
3336                              *sectors_per_chunk + chunk_offset,
3337                              previous,
3338                              &dd_idx, sh);
3339 }
3340
3341 static void
3342 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3343                      struct stripe_head_state *s, int disks)
3344 {
3345         int i;
3346         BUG_ON(sh->batch_head);
3347         for (i = disks; i--; ) {
3348                 struct bio *bi;
3349                 int bitmap_end = 0;
3350
3351                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3352                         struct md_rdev *rdev;
3353                         rcu_read_lock();
3354                         rdev = rcu_dereference(conf->disks[i].rdev);
3355                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3356                             !test_bit(Faulty, &rdev->flags))
3357                                 atomic_inc(&rdev->nr_pending);
3358                         else
3359                                 rdev = NULL;
3360                         rcu_read_unlock();
3361                         if (rdev) {
3362                                 if (!rdev_set_badblocks(
3363                                             rdev,
3364                                             sh->sector,
3365                                             STRIPE_SECTORS, 0))
3366                                         md_error(conf->mddev, rdev);
3367                                 rdev_dec_pending(rdev, conf->mddev);
3368                         }
3369                 }
3370                 spin_lock_irq(&sh->stripe_lock);
3371                 /* fail all writes first */
3372                 bi = sh->dev[i].towrite;
3373                 sh->dev[i].towrite = NULL;
3374                 sh->overwrite_disks = 0;
3375                 spin_unlock_irq(&sh->stripe_lock);
3376                 if (bi)
3377                         bitmap_end = 1;
3378
3379                 log_stripe_write_finished(sh);
3380
3381                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3382                         wake_up(&conf->wait_for_overlap);
3383
3384                 while (bi && bi->bi_iter.bi_sector <
3385                         sh->dev[i].sector + STRIPE_SECTORS) {
3386                         struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
3387
3388                         md_write_end(conf->mddev);
3389                         bio_io_error(bi);
3390                         bi = nextbi;
3391                 }
3392                 if (bitmap_end)
3393                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3394                                 STRIPE_SECTORS, 0, 0);
3395                 bitmap_end = 0;
3396                 /* and fail all 'written' */
3397                 bi = sh->dev[i].written;
3398                 sh->dev[i].written = NULL;
3399                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3400                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3401                         sh->dev[i].page = sh->dev[i].orig_page;
3402                 }
3403
3404                 if (bi) bitmap_end = 1;
3405                 while (bi && bi->bi_iter.bi_sector <
3406                        sh->dev[i].sector + STRIPE_SECTORS) {
3407                         struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
3408
3409                         md_write_end(conf->mddev);
3410                         bio_io_error(bi);
3411                         bi = bi2;
3412                 }
3413
3414                 /* fail any reads if this device is non-operational and
3415                  * the data has not reached the cache yet.
3416                  */
3417                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3418                     s->failed > conf->max_degraded &&
3419                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3420                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3421                         spin_lock_irq(&sh->stripe_lock);
3422                         bi = sh->dev[i].toread;
3423                         sh->dev[i].toread = NULL;
3424                         spin_unlock_irq(&sh->stripe_lock);
3425                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3426                                 wake_up(&conf->wait_for_overlap);
3427                         if (bi)
3428                                 s->to_read--;
3429                         while (bi && bi->bi_iter.bi_sector <
3430                                sh->dev[i].sector + STRIPE_SECTORS) {
3431                                 struct bio *nextbi =
3432                                         r5_next_bio(bi, sh->dev[i].sector);
3433
3434                                 bio_io_error(bi);
3435                                 bi = nextbi;
3436                         }
3437                 }
3438                 if (bitmap_end)
3439                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3440                                         STRIPE_SECTORS, 0, 0);
3441                 /* If we were in the middle of a write the parity block might
3442                  * still be locked - so just clear all R5_LOCKED flags
3443                  */
3444                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3445         }
3446         s->to_write = 0;
3447         s->written = 0;
3448
3449         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3450                 if (atomic_dec_and_test(&conf->pending_full_writes))
3451                         md_wakeup_thread(conf->mddev->thread);
3452 }
3453
3454 static void
3455 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3456                    struct stripe_head_state *s)
3457 {
3458         int abort = 0;
3459         int i;
3460
3461         BUG_ON(sh->batch_head);
3462         clear_bit(STRIPE_SYNCING, &sh->state);
3463         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3464                 wake_up(&conf->wait_for_overlap);
3465         s->syncing = 0;
3466         s->replacing = 0;
3467         /* There is nothing more to do for sync/check/repair.
3468          * Don't even need to abort as that is handled elsewhere
3469          * if needed, and not always wanted e.g. if there is a known
3470          * bad block here.
3471          * For recover/replace we need to record a bad block on all
3472          * non-sync devices, or abort the recovery
3473          */
3474         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3475                 /* During recovery devices cannot be removed, so
3476                  * locking and refcounting of rdevs is not needed
3477                  */
3478                 rcu_read_lock();
3479                 for (i = 0; i < conf->raid_disks; i++) {
3480                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3481                         if (rdev
3482                             && !test_bit(Faulty, &rdev->flags)
3483                             && !test_bit(In_sync, &rdev->flags)
3484                             && !rdev_set_badblocks(rdev, sh->sector,
3485                                                    STRIPE_SECTORS, 0))
3486                                 abort = 1;
3487                         rdev = rcu_dereference(conf->disks[i].replacement);
3488                         if (rdev
3489                             && !test_bit(Faulty, &rdev->flags)
3490                             && !test_bit(In_sync, &rdev->flags)
3491                             && !rdev_set_badblocks(rdev, sh->sector,
3492                                                    STRIPE_SECTORS, 0))
3493                                 abort = 1;
3494                 }
3495                 rcu_read_unlock();
3496                 if (abort)
3497                         conf->recovery_disabled =
3498                                 conf->mddev->recovery_disabled;
3499         }
3500         md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
3501 }
3502
3503 static int want_replace(struct stripe_head *sh, int disk_idx)
3504 {
3505         struct md_rdev *rdev;
3506         int rv = 0;
3507
3508         rcu_read_lock();
3509         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3510         if (rdev
3511             && !test_bit(Faulty, &rdev->flags)
3512             && !test_bit(In_sync, &rdev->flags)
3513             && (rdev->recovery_offset <= sh->sector
3514                 || rdev->mddev->recovery_cp <= sh->sector))
3515                 rv = 1;
3516         rcu_read_unlock();
3517         return rv;
3518 }
3519
3520 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3521                            int disk_idx, int disks)
3522 {
3523         struct r5dev *dev = &sh->dev[disk_idx];
3524         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3525                                   &sh->dev[s->failed_num[1]] };
3526         int i;
3527
3528
3529         if (test_bit(R5_LOCKED, &dev->flags) ||
3530             test_bit(R5_UPTODATE, &dev->flags))
3531                 /* No point reading this as we already have it or have
3532                  * decided to get it.
3533                  */
3534                 return 0;
3535
3536         if (dev->toread ||
3537             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3538                 /* We need this block to directly satisfy a request */
3539                 return 1;
3540
3541         if (s->syncing || s->expanding ||
3542             (s->replacing && want_replace(sh, disk_idx)))
3543                 /* When syncing, or expanding we read everything.
3544                  * When replacing, we need the replaced block.
3545                  */
3546                 return 1;
3547
3548         if ((s->failed >= 1 && fdev[0]->toread) ||
3549             (s->failed >= 2 && fdev[1]->toread))
3550                 /* If we want to read from a failed device, then
3551                  * we need to actually read every other device.
3552                  */
3553                 return 1;
3554
3555         /* Sometimes neither read-modify-write nor reconstruct-write
3556          * cycles can work.  In those cases we read every block we
3557          * can.  Then the parity-update is certain to have enough to
3558          * work with.
3559          * This can only be a problem when we need to write something,
3560          * and some device has failed.  If either of those tests
3561          * fail we need look no further.
3562          */
3563         if (!s->failed || !s->to_write)
3564                 return 0;
3565
3566         if (test_bit(R5_Insync, &dev->flags) &&
3567             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3568                 /* Pre-reads at not permitted until after short delay
3569                  * to gather multiple requests.  However if this
3570                  * device is no Insync, the block could only be computed
3571                  * and there is no need to delay that.
3572                  */
3573                 return 0;
3574
3575         for (i = 0; i < s->failed && i < 2; i++) {
3576                 if (fdev[i]->towrite &&
3577                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3578                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3579                         /* If we have a partial write to a failed
3580                          * device, then we will need to reconstruct
3581                          * the content of that device, so all other
3582                          * devices must be read.
3583                          */
3584                         return 1;
3585         }
3586
3587         /* If we are forced to do a reconstruct-write, either because
3588          * the current RAID6 implementation only supports that, or
3589          * because parity cannot be trusted and we are currently
3590          * recovering it, there is extra need to be careful.
3591          * If one of the devices that we would need to read, because
3592          * it is not being overwritten (and maybe not written at all)
3593          * is missing/faulty, then we need to read everything we can.
3594          */
3595         if (sh->raid_conf->level != 6 &&
3596             sh->raid_conf->rmw_level != PARITY_DISABLE_RMW &&
3597             sh->sector < sh->raid_conf->mddev->recovery_cp)
3598                 /* reconstruct-write isn't being forced */
3599                 return 0;
3600         for (i = 0; i < s->failed && i < 2; i++) {
3601                 if (s->failed_num[i] != sh->pd_idx &&
3602                     s->failed_num[i] != sh->qd_idx &&
3603                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3604                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3605                         return 1;
3606         }
3607
3608         return 0;
3609 }
3610
3611 /* fetch_block - checks the given member device to see if its data needs
3612  * to be read or computed to satisfy a request.
3613  *
3614  * Returns 1 when no more member devices need to be checked, otherwise returns
3615  * 0 to tell the loop in handle_stripe_fill to continue
3616  */
3617 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3618                        int disk_idx, int disks)
3619 {
3620         struct r5dev *dev = &sh->dev[disk_idx];
3621
3622         /* is the data in this block needed, and can we get it? */
3623         if (need_this_block(sh, s, disk_idx, disks)) {
3624                 /* we would like to get this block, possibly by computing it,
3625                  * otherwise read it if the backing disk is insync
3626                  */
3627                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3628                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3629                 BUG_ON(sh->batch_head);
3630
3631                 /*
3632                  * In the raid6 case if the only non-uptodate disk is P
3633                  * then we already trusted P to compute the other failed
3634                  * drives. It is safe to compute rather than re-read P.
3635                  * In other cases we only compute blocks from failed
3636                  * devices, otherwise check/repair might fail to detect
3637                  * a real inconsistency.
3638                  */
3639
3640                 if ((s->uptodate == disks - 1) &&
3641                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3642                     (s->failed && (disk_idx == s->failed_num[0] ||
3643                                    disk_idx == s->failed_num[1])))) {
3644                         /* have disk failed, and we're requested to fetch it;
3645                          * do compute it
3646                          */
3647                         pr_debug("Computing stripe %llu block %d\n",
3648                                (unsigned long long)sh->sector, disk_idx);
3649                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3650                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3651                         set_bit(R5_Wantcompute, &dev->flags);
3652                         sh->ops.target = disk_idx;
3653                         sh->ops.target2 = -1; /* no 2nd target */
3654                         s->req_compute = 1;
3655                         /* Careful: from this point on 'uptodate' is in the eye
3656                          * of raid_run_ops which services 'compute' operations
3657                          * before writes. R5_Wantcompute flags a block that will
3658                          * be R5_UPTODATE by the time it is needed for a
3659                          * subsequent operation.
3660                          */
3661                         s->uptodate++;
3662                         return 1;
3663                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3664                         /* Computing 2-failure is *very* expensive; only
3665                          * do it if failed >= 2
3666                          */
3667                         int other;
3668                         for (other = disks; other--; ) {
3669                                 if (other == disk_idx)
3670                                         continue;
3671                                 if (!test_bit(R5_UPTODATE,
3672                                       &sh->dev[other].flags))
3673                                         break;
3674                         }
3675                         BUG_ON(other < 0);
3676                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3677                                (unsigned long long)sh->sector,
3678                                disk_idx, other);
3679                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3680                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3681                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3682                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3683                         sh->ops.target = disk_idx;
3684                         sh->ops.target2 = other;
3685                         s->uptodate += 2;
3686                         s->req_compute = 1;
3687                         return 1;
3688                 } else if (test_bit(R5_Insync, &dev->flags)) {
3689                         set_bit(R5_LOCKED, &dev->flags);
3690                         set_bit(R5_Wantread, &dev->flags);
3691                         s->locked++;
3692                         pr_debug("Reading block %d (sync=%d)\n",
3693                                 disk_idx, s->syncing);
3694                 }
3695         }
3696
3697         return 0;
3698 }
3699
3700 /**
3701  * handle_stripe_fill - read or compute data to satisfy pending requests.
3702  */
3703 static void handle_stripe_fill(struct stripe_head *sh,
3704                                struct stripe_head_state *s,
3705                                int disks)
3706 {
3707         int i;
3708
3709         /* look for blocks to read/compute, skip this if a compute
3710          * is already in flight, or if the stripe contents are in the
3711          * midst of changing due to a write
3712          */
3713         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3714             !sh->reconstruct_state) {
3715
3716                 /*
3717                  * For degraded stripe with data in journal, do not handle
3718                  * read requests yet, instead, flush the stripe to raid
3719                  * disks first, this avoids handling complex rmw of write
3720                  * back cache (prexor with orig_page, and then xor with
3721                  * page) in the read path
3722                  */
3723                 if (s->injournal && s->failed) {
3724                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
3725                                 r5c_make_stripe_write_out(sh);
3726                         goto out;
3727                 }
3728
3729                 for (i = disks; i--; )
3730                         if (fetch_block(sh, s, i, disks))
3731                                 break;
3732         }
3733 out:
3734         set_bit(STRIPE_HANDLE, &sh->state);
3735 }
3736
3737 static void break_stripe_batch_list(struct stripe_head *head_sh,
3738                                     unsigned long handle_flags);
3739 /* handle_stripe_clean_event
3740  * any written block on an uptodate or failed drive can be returned.
3741  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
3742  * never LOCKED, so we don't need to test 'failed' directly.
3743  */
3744 static void handle_stripe_clean_event(struct r5conf *conf,
3745         struct stripe_head *sh, int disks)
3746 {
3747         int i;
3748         struct r5dev *dev;
3749         int discard_pending = 0;
3750         struct stripe_head *head_sh = sh;
3751         bool do_endio = false;
3752
3753         for (i = disks; i--; )
3754                 if (sh->dev[i].written) {
3755                         dev = &sh->dev[i];
3756                         if (!test_bit(R5_LOCKED, &dev->flags) &&
3757                             (test_bit(R5_UPTODATE, &dev->flags) ||
3758                              test_bit(R5_Discard, &dev->flags) ||
3759                              test_bit(R5_SkipCopy, &dev->flags))) {
3760                                 /* We can return any write requests */
3761                                 struct bio *wbi, *wbi2;
3762                                 pr_debug("Return write for disc %d\n", i);
3763                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
3764                                         clear_bit(R5_UPTODATE, &dev->flags);
3765                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
3766                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
3767                                 }
3768                                 do_endio = true;
3769
3770 returnbi:
3771                                 dev->page = dev->orig_page;
3772                                 wbi = dev->written;
3773                                 dev->written = NULL;
3774                                 while (wbi && wbi->bi_iter.bi_sector <
3775                                         dev->sector + STRIPE_SECTORS) {
3776                                         wbi2 = r5_next_bio(wbi, dev->sector);
3777                                         md_write_end(conf->mddev);
3778                                         bio_endio(wbi);
3779                                         wbi = wbi2;
3780                                 }
3781                                 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3782                                                 STRIPE_SECTORS,
3783                                          !test_bit(STRIPE_DEGRADED, &sh->state),
3784                                                 0);
3785                                 if (head_sh->batch_head) {
3786                                         sh = list_first_entry(&sh->batch_list,
3787                                                               struct stripe_head,
3788                                                               batch_list);
3789                                         if (sh != head_sh) {
3790                                                 dev = &sh->dev[i];
3791                                                 goto returnbi;
3792                                         }
3793                                 }
3794                                 sh = head_sh;
3795                                 dev = &sh->dev[i];
3796                         } else if (test_bit(R5_Discard, &dev->flags))
3797                                 discard_pending = 1;
3798                 }
3799
3800         log_stripe_write_finished(sh);
3801
3802         if (!discard_pending &&
3803             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
3804                 int hash;
3805                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
3806                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
3807                 if (sh->qd_idx >= 0) {
3808                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
3809                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
3810                 }
3811                 /* now that discard is done we can proceed with any sync */
3812                 clear_bit(STRIPE_DISCARD, &sh->state);
3813                 /*
3814                  * SCSI discard will change some bio fields and the stripe has
3815                  * no updated data, so remove it from hash list and the stripe
3816                  * will be reinitialized
3817                  */
3818 unhash:
3819                 hash = sh->hash_lock_index;
3820                 spin_lock_irq(conf->hash_locks + hash);
3821                 remove_hash(sh);
3822                 spin_unlock_irq(conf->hash_locks + hash);
3823                 if (head_sh->batch_head) {
3824                         sh = list_first_entry(&sh->batch_list,
3825                                               struct stripe_head, batch_list);
3826                         if (sh != head_sh)
3827                                         goto unhash;
3828                 }
3829                 sh = head_sh;
3830
3831                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
3832                         set_bit(STRIPE_HANDLE, &sh->state);
3833
3834         }
3835
3836         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3837                 if (atomic_dec_and_test(&conf->pending_full_writes))
3838                         md_wakeup_thread(conf->mddev->thread);
3839
3840         if (head_sh->batch_head && do_endio)
3841                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
3842 }
3843
3844 /*
3845  * For RMW in write back cache, we need extra page in prexor to store the
3846  * old data. This page is stored in dev->orig_page.
3847  *
3848  * This function checks whether we have data for prexor. The exact logic
3849  * is:
3850  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
3851  */
3852 static inline bool uptodate_for_rmw(struct r5dev *dev)
3853 {
3854         return (test_bit(R5_UPTODATE, &dev->flags)) &&
3855                 (!test_bit(R5_InJournal, &dev->flags) ||
3856                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
3857 }
3858
3859 static int handle_stripe_dirtying(struct r5conf *conf,
3860                                   struct stripe_head *sh,
3861                                   struct stripe_head_state *s,
3862                                   int disks)
3863 {
3864         int rmw = 0, rcw = 0, i;
3865         sector_t recovery_cp = conf->mddev->recovery_cp;
3866
3867         /* Check whether resync is now happening or should start.
3868          * If yes, then the array is dirty (after unclean shutdown or
3869          * initial creation), so parity in some stripes might be inconsistent.
3870          * In this case, we need to always do reconstruct-write, to ensure
3871          * that in case of drive failure or read-error correction, we
3872          * generate correct data from the parity.
3873          */
3874         if (conf->rmw_level == PARITY_DISABLE_RMW ||
3875             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
3876              s->failed == 0)) {
3877                 /* Calculate the real rcw later - for now make it
3878                  * look like rcw is cheaper
3879                  */
3880                 rcw = 1; rmw = 2;
3881                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
3882                          conf->rmw_level, (unsigned long long)recovery_cp,
3883                          (unsigned long long)sh->sector);
3884         } else for (i = disks; i--; ) {
3885                 /* would I have to read this buffer for read_modify_write */
3886                 struct r5dev *dev = &sh->dev[i];
3887                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3888                      i == sh->pd_idx || i == sh->qd_idx ||
3889                      test_bit(R5_InJournal, &dev->flags)) &&
3890                     !test_bit(R5_LOCKED, &dev->flags) &&
3891                     !(uptodate_for_rmw(dev) ||
3892                       test_bit(R5_Wantcompute, &dev->flags))) {
3893                         if (test_bit(R5_Insync, &dev->flags))
3894                                 rmw++;
3895                         else
3896                                 rmw += 2*disks;  /* cannot read it */
3897                 }
3898                 /* Would I have to read this buffer for reconstruct_write */
3899                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3900                     i != sh->pd_idx && i != sh->qd_idx &&
3901                     !test_bit(R5_LOCKED, &dev->flags) &&
3902                     !(test_bit(R5_UPTODATE, &dev->flags) ||
3903                       test_bit(R5_Wantcompute, &dev->flags))) {
3904                         if (test_bit(R5_Insync, &dev->flags))
3905                                 rcw++;
3906                         else
3907                                 rcw += 2*disks;
3908                 }
3909         }
3910
3911         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
3912                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
3913         set_bit(STRIPE_HANDLE, &sh->state);
3914         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
3915                 /* prefer read-modify-write, but need to get some data */
3916                 if (conf->mddev->queue)
3917                         blk_add_trace_msg(conf->mddev->queue,
3918                                           "raid5 rmw %llu %d",
3919                                           (unsigned long long)sh->sector, rmw);
3920                 for (i = disks; i--; ) {
3921                         struct r5dev *dev = &sh->dev[i];
3922                         if (test_bit(R5_InJournal, &dev->flags) &&
3923                             dev->page == dev->orig_page &&
3924                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
3925                                 /* alloc page for prexor */
3926                                 struct page *p = alloc_page(GFP_NOIO);
3927
3928                                 if (p) {
3929                                         dev->orig_page = p;
3930                                         continue;
3931                                 }
3932
3933                                 /*
3934                                  * alloc_page() failed, try use
3935                                  * disk_info->extra_page
3936                                  */
3937                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
3938                                                       &conf->cache_state)) {
3939                                         r5c_use_extra_page(sh);
3940                                         break;
3941                                 }
3942
3943                                 /* extra_page in use, add to delayed_list */
3944                                 set_bit(STRIPE_DELAYED, &sh->state);
3945                                 s->waiting_extra_page = 1;
3946                                 return -EAGAIN;
3947                         }
3948                 }
3949
3950                 for (i = disks; i--; ) {
3951                         struct r5dev *dev = &sh->dev[i];
3952                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3953                              i == sh->pd_idx || i == sh->qd_idx ||
3954                              test_bit(R5_InJournal, &dev->flags)) &&
3955                             !test_bit(R5_LOCKED, &dev->flags) &&
3956                             !(uptodate_for_rmw(dev) ||
3957                               test_bit(R5_Wantcompute, &dev->flags)) &&
3958                             test_bit(R5_Insync, &dev->flags)) {
3959                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
3960                                              &sh->state)) {
3961                                         pr_debug("Read_old block %d for r-m-w\n",
3962                                                  i);
3963                                         set_bit(R5_LOCKED, &dev->flags);
3964                                         set_bit(R5_Wantread, &dev->flags);
3965                                         s->locked++;
3966                                 } else {
3967                                         set_bit(STRIPE_DELAYED, &sh->state);
3968                                         set_bit(STRIPE_HANDLE, &sh->state);
3969                                 }
3970                         }
3971                 }
3972         }
3973         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
3974                 /* want reconstruct write, but need to get some data */
3975                 int qread =0;
3976                 rcw = 0;
3977                 for (i = disks; i--; ) {
3978                         struct r5dev *dev = &sh->dev[i];
3979                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3980                             i != sh->pd_idx && i != sh->qd_idx &&
3981                             !test_bit(R5_LOCKED, &dev->flags) &&
3982                             !(test_bit(R5_UPTODATE, &dev->flags) ||
3983                               test_bit(R5_Wantcompute, &dev->flags))) {
3984                                 rcw++;
3985                                 if (test_bit(R5_Insync, &dev->flags) &&
3986                                     test_bit(STRIPE_PREREAD_ACTIVE,
3987                                              &sh->state)) {
3988                                         pr_debug("Read_old block "
3989                                                 "%d for Reconstruct\n", i);
3990                                         set_bit(R5_LOCKED, &dev->flags);
3991                                         set_bit(R5_Wantread, &dev->flags);
3992                                         s->locked++;
3993                                         qread++;
3994                                 } else {
3995                                         set_bit(STRIPE_DELAYED, &sh->state);
3996                                         set_bit(STRIPE_HANDLE, &sh->state);
3997                                 }
3998                         }
3999                 }
4000                 if (rcw && conf->mddev->queue)
4001                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
4002                                           (unsigned long long)sh->sector,
4003                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
4004         }
4005
4006         if (rcw > disks && rmw > disks &&
4007             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4008                 set_bit(STRIPE_DELAYED, &sh->state);
4009
4010         /* now if nothing is locked, and if we have enough data,
4011          * we can start a write request
4012          */
4013         /* since handle_stripe can be called at any time we need to handle the
4014          * case where a compute block operation has been submitted and then a
4015          * subsequent call wants to start a write request.  raid_run_ops only
4016          * handles the case where compute block and reconstruct are requested
4017          * simultaneously.  If this is not the case then new writes need to be
4018          * held off until the compute completes.
4019          */
4020         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4021             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4022              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4023                 schedule_reconstruction(sh, s, rcw == 0, 0);
4024         return 0;
4025 }
4026
4027 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4028                                 struct stripe_head_state *s, int disks)
4029 {
4030         struct r5dev *dev = NULL;
4031
4032         BUG_ON(sh->batch_head);
4033         set_bit(STRIPE_HANDLE, &sh->state);
4034
4035         switch (sh->check_state) {
4036         case check_state_idle:
4037                 /* start a new check operation if there are no failures */
4038                 if (s->failed == 0) {
4039                         BUG_ON(s->uptodate != disks);
4040                         sh->check_state = check_state_run;
4041                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4042                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4043                         s->uptodate--;
4044                         break;
4045                 }
4046                 dev = &sh->dev[s->failed_num[0]];
4047                 /* fall through */
4048         case check_state_compute_result:
4049                 sh->check_state = check_state_idle;
4050                 if (!dev)
4051                         dev = &sh->dev[sh->pd_idx];
4052
4053                 /* check that a write has not made the stripe insync */
4054                 if (test_bit(STRIPE_INSYNC, &sh->state))
4055                         break;
4056
4057                 /* either failed parity check, or recovery is happening */
4058                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4059                 BUG_ON(s->uptodate != disks);
4060
4061                 set_bit(R5_LOCKED, &dev->flags);
4062                 s->locked++;
4063                 set_bit(R5_Wantwrite, &dev->flags);
4064
4065                 clear_bit(STRIPE_DEGRADED, &sh->state);
4066                 set_bit(STRIPE_INSYNC, &sh->state);
4067                 break;
4068         case check_state_run:
4069                 break; /* we will be called again upon completion */
4070         case check_state_check_result:
4071                 sh->check_state = check_state_idle;
4072
4073                 /* if a failure occurred during the check operation, leave
4074                  * STRIPE_INSYNC not set and let the stripe be handled again
4075                  */
4076                 if (s->failed)
4077                         break;
4078
4079                 /* handle a successful check operation, if parity is correct
4080                  * we are done.  Otherwise update the mismatch count and repair
4081                  * parity if !MD_RECOVERY_CHECK
4082                  */
4083                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4084                         /* parity is correct (on disc,
4085                          * not in buffer any more)
4086                          */
4087                         set_bit(STRIPE_INSYNC, &sh->state);
4088                 else {
4089                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4090                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4091                                 /* don't try to repair!! */
4092                                 set_bit(STRIPE_INSYNC, &sh->state);
4093                                 pr_warn_ratelimited("%s: mismatch sector in range "
4094                                                     "%llu-%llu\n", mdname(conf->mddev),
4095                                                     (unsigned long long) sh->sector,
4096                                                     (unsigned long long) sh->sector +
4097                                                     STRIPE_SECTORS);
4098                         } else {
4099                                 sh->check_state = check_state_compute_run;
4100                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4101                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4102                                 set_bit(R5_Wantcompute,
4103                                         &sh->dev[sh->pd_idx].flags);
4104                                 sh->ops.target = sh->pd_idx;
4105                                 sh->ops.target2 = -1;
4106                                 s->uptodate++;
4107                         }
4108                 }
4109                 break;
4110         case check_state_compute_run:
4111                 break;
4112         default:
4113                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4114                        __func__, sh->check_state,
4115                        (unsigned long long) sh->sector);
4116                 BUG();
4117         }
4118 }
4119
4120 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4121                                   struct stripe_head_state *s,
4122                                   int disks)
4123 {
4124         int pd_idx = sh->pd_idx;
4125         int qd_idx = sh->qd_idx;
4126         struct r5dev *dev;
4127
4128         BUG_ON(sh->batch_head);
4129         set_bit(STRIPE_HANDLE, &sh->state);
4130
4131         BUG_ON(s->failed > 2);
4132
4133         /* Want to check and possibly repair P and Q.
4134          * However there could be one 'failed' device, in which
4135          * case we can only check one of them, possibly using the
4136          * other to generate missing data
4137          */
4138
4139         switch (sh->check_state) {
4140         case check_state_idle:
4141                 /* start a new check operation if there are < 2 failures */
4142                 if (s->failed == s->q_failed) {
4143                         /* The only possible failed device holds Q, so it
4144                          * makes sense to check P (If anything else were failed,
4145                          * we would have used P to recreate it).
4146                          */
4147                         sh->check_state = check_state_run;
4148                 }
4149                 if (!s->q_failed && s->failed < 2) {
4150                         /* Q is not failed, and we didn't use it to generate
4151                          * anything, so it makes sense to check it
4152                          */
4153                         if (sh->check_state == check_state_run)
4154                                 sh->check_state = check_state_run_pq;
4155                         else
4156                                 sh->check_state = check_state_run_q;
4157                 }
4158
4159                 /* discard potentially stale zero_sum_result */
4160                 sh->ops.zero_sum_result = 0;
4161
4162                 if (sh->check_state == check_state_run) {
4163                         /* async_xor_zero_sum destroys the contents of P */
4164                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4165                         s->uptodate--;
4166                 }
4167                 if (sh->check_state >= check_state_run &&
4168                     sh->check_state <= check_state_run_pq) {
4169                         /* async_syndrome_zero_sum preserves P and Q, so
4170                          * no need to mark them !uptodate here
4171                          */
4172                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4173                         break;
4174                 }
4175
4176                 /* we have 2-disk failure */
4177                 BUG_ON(s->failed != 2);
4178                 /* fall through */
4179         case check_state_compute_result:
4180                 sh->check_state = check_state_idle;
4181
4182                 /* check that a write has not made the stripe insync */
4183                 if (test_bit(STRIPE_INSYNC, &sh->state))
4184                         break;
4185
4186                 /* now write out any block on a failed drive,
4187                  * or P or Q if they were recomputed
4188                  */
4189                 dev = NULL;
4190                 if (s->failed == 2) {
4191                         dev = &sh->dev[s->failed_num[1]];
4192                         s->locked++;
4193                         set_bit(R5_LOCKED, &dev->flags);
4194                         set_bit(R5_Wantwrite, &dev->flags);
4195                 }
4196                 if (s->failed >= 1) {
4197                         dev = &sh->dev[s->failed_num[0]];
4198                         s->locked++;
4199                         set_bit(R5_LOCKED, &dev->flags);
4200                         set_bit(R5_Wantwrite, &dev->flags);
4201                 }
4202                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4203                         dev = &sh->dev[pd_idx];
4204                         s->locked++;
4205                         set_bit(R5_LOCKED, &dev->flags);
4206                         set_bit(R5_Wantwrite, &dev->flags);
4207                 }
4208                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4209                         dev = &sh->dev[qd_idx];
4210                         s->locked++;
4211                         set_bit(R5_LOCKED, &dev->flags);
4212                         set_bit(R5_Wantwrite, &dev->flags);
4213                 }
4214                 if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4215                               "%s: disk%td not up to date\n",
4216                               mdname(conf->mddev),
4217                               dev - (struct r5dev *) &sh->dev)) {
4218                         clear_bit(R5_LOCKED, &dev->flags);
4219                         clear_bit(R5_Wantwrite, &dev->flags);
4220                         s->locked--;
4221                 }
4222                 clear_bit(STRIPE_DEGRADED, &sh->state);
4223
4224                 set_bit(STRIPE_INSYNC, &sh->state);
4225                 break;
4226         case check_state_run:
4227         case check_state_run_q:
4228         case check_state_run_pq:
4229                 break; /* we will be called again upon completion */
4230         case check_state_check_result:
4231                 sh->check_state = check_state_idle;
4232
4233                 /* handle a successful check operation, if parity is correct
4234                  * we are done.  Otherwise update the mismatch count and repair
4235                  * parity if !MD_RECOVERY_CHECK
4236                  */
4237                 if (sh->ops.zero_sum_result == 0) {
4238                         /* both parities are correct */
4239                         if (!s->failed)
4240                                 set_bit(STRIPE_INSYNC, &sh->state);
4241                         else {
4242                                 /* in contrast to the raid5 case we can validate
4243                                  * parity, but still have a failure to write
4244                                  * back
4245                                  */
4246                                 sh->check_state = check_state_compute_result;
4247                                 /* Returning at this point means that we may go
4248                                  * off and bring p and/or q uptodate again so
4249                                  * we make sure to check zero_sum_result again
4250                                  * to verify if p or q need writeback
4251                                  */
4252                         }
4253                 } else {
4254                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4255                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4256                                 /* don't try to repair!! */
4257                                 set_bit(STRIPE_INSYNC, &sh->state);
4258                                 pr_warn_ratelimited("%s: mismatch sector in range "
4259                                                     "%llu-%llu\n", mdname(conf->mddev),
4260                                                     (unsigned long long) sh->sector,
4261                                                     (unsigned long long) sh->sector +
4262                                                     STRIPE_SECTORS);
4263                         } else {
4264                                 int *target = &sh->ops.target;
4265
4266                                 sh->ops.target = -1;
4267                                 sh->ops.target2 = -1;
4268                                 sh->check_state = check_state_compute_run;
4269                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4270                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4271                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4272                                         set_bit(R5_Wantcompute,
4273                                                 &sh->dev[pd_idx].flags);
4274                                         *target = pd_idx;
4275                                         target = &sh->ops.target2;
4276                                         s->uptodate++;
4277                                 }
4278                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4279                                         set_bit(R5_Wantcompute,
4280                                                 &sh->dev[qd_idx].flags);
4281                                         *target = qd_idx;
4282                                         s->uptodate++;
4283                                 }
4284                         }
4285                 }
4286                 break;
4287         case check_state_compute_run:
4288                 break;
4289         default:
4290                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4291                         __func__, sh->check_state,
4292                         (unsigned long long) sh->sector);
4293                 BUG();
4294         }
4295 }
4296
4297 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4298 {
4299         int i;
4300
4301         /* We have read all the blocks in this stripe and now we need to
4302          * copy some of them into a target stripe for expand.
4303          */
4304         struct dma_async_tx_descriptor *tx = NULL;
4305         BUG_ON(sh->batch_head);
4306         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4307         for (i = 0; i < sh->disks; i++)
4308                 if (i != sh->pd_idx && i != sh->qd_idx) {
4309                         int dd_idx, j;
4310                         struct stripe_head *sh2;
4311                         struct async_submit_ctl submit;
4312
4313                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4314                         sector_t s = raid5_compute_sector(conf, bn, 0,
4315                                                           &dd_idx, NULL);
4316                         sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4317                         if (sh2 == NULL)
4318                                 /* so far only the early blocks of this stripe
4319                                  * have been requested.  When later blocks
4320                                  * get requested, we will try again
4321                                  */
4322                                 continue;
4323                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4324                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4325                                 /* must have already done this block */
4326                                 raid5_release_stripe(sh2);
4327                                 continue;
4328                         }
4329
4330                         /* place all the copies on one channel */
4331                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4332                         tx = async_memcpy(sh2->dev[dd_idx].page,
4333                                           sh->dev[i].page, 0, 0, STRIPE_SIZE,
4334                                           &submit);
4335
4336                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4337                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4338                         for (j = 0; j < conf->raid_disks; j++)
4339                                 if (j != sh2->pd_idx &&
4340                                     j != sh2->qd_idx &&
4341                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4342                                         break;
4343                         if (j == conf->raid_disks) {
4344                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4345                                 set_bit(STRIPE_HANDLE, &sh2->state);
4346                         }
4347                         raid5_release_stripe(sh2);
4348
4349                 }
4350         /* done submitting copies, wait for them to complete */
4351         async_tx_quiesce(&tx);
4352 }
4353
4354 /*
4355  * handle_stripe - do things to a stripe.
4356  *
4357  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4358  * state of various bits to see what needs to be done.
4359  * Possible results:
4360  *    return some read requests which now have data
4361  *    return some write requests which are safely on storage
4362  *    schedule a read on some buffers
4363  *    schedule a write of some buffers
4364  *    return confirmation of parity correctness
4365  *
4366  */
4367
4368 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4369 {
4370         struct r5conf *conf = sh->raid_conf;
4371         int disks = sh->disks;
4372         struct r5dev *dev;
4373         int i;
4374         int do_recovery = 0;
4375
4376         memset(s, 0, sizeof(*s));
4377
4378         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4379         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4380         s->failed_num[0] = -1;
4381         s->failed_num[1] = -1;
4382         s->log_failed = r5l_log_disk_error(conf);
4383
4384         /* Now to look around and see what can be done */
4385         rcu_read_lock();
4386         for (i=disks; i--; ) {
4387                 struct md_rdev *rdev;
4388                 sector_t first_bad;
4389                 int bad_sectors;
4390                 int is_bad = 0;
4391
4392                 dev = &sh->dev[i];
4393
4394                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4395                          i, dev->flags,
4396                          dev->toread, dev->towrite, dev->written);
4397                 /* maybe we can reply to a read
4398                  *
4399                  * new wantfill requests are only permitted while
4400                  * ops_complete_biofill is guaranteed to be inactive
4401                  */
4402                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4403                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4404                         set_bit(R5_Wantfill, &dev->flags);
4405
4406                 /* now count some things */
4407                 if (test_bit(R5_LOCKED, &dev->flags))
4408                         s->locked++;
4409                 if (test_bit(R5_UPTODATE, &dev->flags))
4410                         s->uptodate++;
4411                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4412                         s->compute++;
4413                         BUG_ON(s->compute > 2);
4414                 }
4415
4416                 if (test_bit(R5_Wantfill, &dev->flags))
4417                         s->to_fill++;
4418                 else if (dev->toread)
4419                         s->to_read++;
4420                 if (dev->towrite) {
4421                         s->to_write++;
4422                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4423                                 s->non_overwrite++;
4424                 }
4425                 if (dev->written)
4426                         s->written++;
4427                 /* Prefer to use the replacement for reads, but only
4428                  * if it is recovered enough and has no bad blocks.
4429                  */
4430                 rdev = rcu_dereference(conf->disks[i].replacement);
4431                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4432                     rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
4433                     !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4434                                  &first_bad, &bad_sectors))
4435                         set_bit(R5_ReadRepl, &dev->flags);
4436                 else {
4437                         if (rdev && !test_bit(Faulty, &rdev->flags))
4438                                 set_bit(R5_NeedReplace, &dev->flags);
4439                         else
4440                                 clear_bit(R5_NeedReplace, &dev->flags);
4441                         rdev = rcu_dereference(conf->disks[i].rdev);
4442                         clear_bit(R5_ReadRepl, &dev->flags);
4443                 }
4444                 if (rdev && test_bit(Faulty, &rdev->flags))
4445                         rdev = NULL;
4446                 if (rdev) {
4447                         is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4448                                              &first_bad, &bad_sectors);
4449                         if (s->blocked_rdev == NULL
4450                             && (test_bit(Blocked, &rdev->flags)
4451                                 || is_bad < 0)) {
4452                                 if (is_bad < 0)
4453                                         set_bit(BlockedBadBlocks,
4454                                                 &rdev->flags);
4455                                 s->blocked_rdev = rdev;
4456                                 atomic_inc(&rdev->nr_pending);
4457                         }
4458                 }
4459                 clear_bit(R5_Insync, &dev->flags);
4460                 if (!rdev)
4461                         /* Not in-sync */;
4462                 else if (is_bad) {
4463                         /* also not in-sync */
4464                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4465                             test_bit(R5_UPTODATE, &dev->flags)) {
4466                                 /* treat as in-sync, but with a read error
4467                                  * which we can now try to correct
4468                                  */
4469                                 set_bit(R5_Insync, &dev->flags);
4470                                 set_bit(R5_ReadError, &dev->flags);
4471                         }
4472                 } else if (test_bit(In_sync, &rdev->flags))
4473                         set_bit(R5_Insync, &dev->flags);
4474                 else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
4475                         /* in sync if before recovery_offset */
4476                         set_bit(R5_Insync, &dev->flags);
4477                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4478                          test_bit(R5_Expanded, &dev->flags))
4479                         /* If we've reshaped into here, we assume it is Insync.
4480                          * We will shortly update recovery_offset to make
4481                          * it official.
4482                          */
4483                         set_bit(R5_Insync, &dev->flags);
4484
4485                 if (test_bit(R5_WriteError, &dev->flags)) {
4486                         /* This flag does not apply to '.replacement'
4487                          * only to .rdev, so make sure to check that*/
4488                         struct md_rdev *rdev2 = rcu_dereference(
4489                                 conf->disks[i].rdev);
4490                         if (rdev2 == rdev)
4491                                 clear_bit(R5_Insync, &dev->flags);
4492                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4493                                 s->handle_bad_blocks = 1;
4494                                 atomic_inc(&rdev2->nr_pending);
4495                         } else
4496                                 clear_bit(R5_WriteError, &dev->flags);
4497                 }
4498                 if (test_bit(R5_MadeGood, &dev->flags)) {
4499                         /* This flag does not apply to '.replacement'
4500                          * only to .rdev, so make sure to check that*/
4501                         struct md_rdev *rdev2 = rcu_dereference(
4502                                 conf->disks[i].rdev);
4503                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4504                                 s->handle_bad_blocks = 1;
4505                                 atomic_inc(&rdev2->nr_pending);
4506                         } else
4507                                 clear_bit(R5_MadeGood, &dev->flags);
4508                 }
4509                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4510                         struct md_rdev *rdev2 = rcu_dereference(
4511                                 conf->disks[i].replacement);
4512                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4513                                 s->handle_bad_blocks = 1;
4514                                 atomic_inc(&rdev2->nr_pending);
4515                         } else
4516                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4517                 }
4518                 if (!test_bit(R5_Insync, &dev->flags)) {
4519                         /* The ReadError flag will just be confusing now */
4520                         clear_bit(R5_ReadError, &dev->flags);
4521                         clear_bit(R5_ReWrite, &dev->flags);
4522                 }
4523                 if (test_bit(R5_ReadError, &dev->flags))
4524                         clear_bit(R5_Insync, &dev->flags);
4525                 if (!test_bit(R5_Insync, &dev->flags)) {
4526                         if (s->failed < 2)
4527                                 s->failed_num[s->failed] = i;
4528                         s->failed++;
4529                         if (rdev && !test_bit(Faulty, &rdev->flags))
4530                                 do_recovery = 1;
4531                         else if (!rdev) {
4532                                 rdev = rcu_dereference(
4533                                     conf->disks[i].replacement);
4534                                 if (rdev && !test_bit(Faulty, &rdev->flags))
4535                                         do_recovery = 1;
4536                         }
4537                 }
4538
4539                 if (test_bit(R5_InJournal, &dev->flags))
4540                         s->injournal++;
4541                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4542                         s->just_cached++;
4543         }
4544         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4545                 /* If there is a failed device being replaced,
4546                  *     we must be recovering.
4547                  * else if we are after recovery_cp, we must be syncing
4548                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4549                  * else we can only be replacing
4550                  * sync and recovery both need to read all devices, and so
4551                  * use the same flag.
4552                  */
4553                 if (do_recovery ||
4554                     sh->sector >= conf->mddev->recovery_cp ||
4555                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4556                         s->syncing = 1;
4557                 else
4558                         s->replacing = 1;
4559         }
4560         rcu_read_unlock();
4561 }
4562
4563 static int clear_batch_ready(struct stripe_head *sh)
4564 {
4565         /* Return '1' if this is a member of batch, or
4566          * '0' if it is a lone stripe or a head which can now be
4567          * handled.
4568          */
4569         struct stripe_head *tmp;
4570         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4571                 return (sh->batch_head && sh->batch_head != sh);
4572         spin_lock(&sh->stripe_lock);
4573         if (!sh->batch_head) {
4574                 spin_unlock(&sh->stripe_lock);
4575                 return 0;
4576         }
4577
4578         /*
4579          * this stripe could be added to a batch list before we check
4580          * BATCH_READY, skips it
4581          */
4582         if (sh->batch_head != sh) {
4583                 spin_unlock(&sh->stripe_lock);
4584                 return 1;
4585         }
4586         spin_lock(&sh->batch_lock);
4587         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4588                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4589         spin_unlock(&sh->batch_lock);
4590         spin_unlock(&sh->stripe_lock);
4591
4592         /*
4593          * BATCH_READY is cleared, no new stripes can be added.
4594          * batch_list can be accessed without lock
4595          */
4596         return 0;
4597 }
4598
4599 static void break_stripe_batch_list(struct stripe_head *head_sh,
4600                                     unsigned long handle_flags)
4601 {
4602         struct stripe_head *sh, *next;
4603         int i;
4604         int do_wakeup = 0;
4605
4606         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4607
4608                 list_del_init(&sh->batch_list);
4609
4610                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4611                                           (1 << STRIPE_SYNCING) |
4612                                           (1 << STRIPE_REPLACED) |
4613                                           (1 << STRIPE_DELAYED) |
4614                                           (1 << STRIPE_BIT_DELAY) |
4615                                           (1 << STRIPE_FULL_WRITE) |
4616                                           (1 << STRIPE_BIOFILL_RUN) |
4617                                           (1 << STRIPE_COMPUTE_RUN)  |
4618                                           (1 << STRIPE_OPS_REQ_PENDING) |
4619                                           (1 << STRIPE_DISCARD) |
4620                                           (1 << STRIPE_BATCH_READY) |
4621                                           (1 << STRIPE_BATCH_ERR) |
4622                                           (1 << STRIPE_BITMAP_PENDING)),
4623                         "stripe state: %lx\n", sh->state);
4624                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4625                                               (1 << STRIPE_REPLACED)),
4626                         "head stripe state: %lx\n", head_sh->state);
4627
4628                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4629                                             (1 << STRIPE_PREREAD_ACTIVE) |
4630                                             (1 << STRIPE_DEGRADED) |
4631                                             (1 << STRIPE_ON_UNPLUG_LIST)),
4632                               head_sh->state & (1 << STRIPE_INSYNC));
4633
4634                 sh->check_state = head_sh->check_state;
4635                 sh->reconstruct_state = head_sh->reconstruct_state;
4636                 for (i = 0; i < sh->disks; i++) {
4637                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4638                                 do_wakeup = 1;
4639                         sh->dev[i].flags = head_sh->dev[i].flags &
4640                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4641                 }
4642                 spin_lock_irq(&sh->stripe_lock);
4643                 sh->batch_head = NULL;
4644                 spin_unlock_irq(&sh->stripe_lock);
4645                 if (handle_flags == 0 ||
4646                     sh->state & handle_flags)
4647                         set_bit(STRIPE_HANDLE, &sh->state);
4648                 raid5_release_stripe(sh);
4649         }
4650         spin_lock_irq(&head_sh->stripe_lock);
4651         head_sh->batch_head = NULL;
4652         spin_unlock_irq(&head_sh->stripe_lock);
4653         for (i = 0; i < head_sh->disks; i++)
4654                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4655                         do_wakeup = 1;
4656         if (head_sh->state & handle_flags)
4657                 set_bit(STRIPE_HANDLE, &head_sh->state);
4658
4659         if (do_wakeup)
4660                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4661 }
4662
4663 static void handle_stripe(struct stripe_head *sh)
4664 {
4665         struct stripe_head_state s;
4666         struct r5conf *conf = sh->raid_conf;
4667         int i;
4668         int prexor;
4669         int disks = sh->disks;
4670         struct r5dev *pdev, *qdev;
4671
4672         clear_bit(STRIPE_HANDLE, &sh->state);
4673         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4674                 /* already being handled, ensure it gets handled
4675                  * again when current action finishes */
4676                 set_bit(STRIPE_HANDLE, &sh->state);
4677                 return;
4678         }
4679
4680         if (clear_batch_ready(sh) ) {
4681                 clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
4682                 return;
4683         }
4684
4685         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4686                 break_stripe_batch_list(sh, 0);
4687
4688         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4689                 spin_lock(&sh->stripe_lock);
4690                 /*
4691                  * Cannot process 'sync' concurrently with 'discard'.
4692                  * Flush data in r5cache before 'sync'.
4693                  */
4694                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
4695                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
4696                     !test_bit(STRIPE_DISCARD, &sh->state) &&
4697                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4698                         set_bit(STRIPE_SYNCING, &sh->state);
4699                         clear_bit(STRIPE_INSYNC, &sh->state);
4700                         clear_bit(STRIPE_REPLACED, &sh->state);
4701                 }
4702                 spin_unlock(&sh->stripe_lock);
4703         }
4704         clear_bit(STRIPE_DELAYED, &sh->state);
4705
4706         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4707                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4708                (unsigned long long)sh->sector, sh->state,
4709                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4710                sh->check_state, sh->reconstruct_state);
4711
4712         analyse_stripe(sh, &s);
4713
4714         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4715                 goto finish;
4716
4717         if (s.handle_bad_blocks ||
4718             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4719                 set_bit(STRIPE_HANDLE, &sh->state);
4720                 goto finish;
4721         }
4722
4723         if (unlikely(s.blocked_rdev)) {
4724                 if (s.syncing || s.expanding || s.expanded ||
4725                     s.replacing || s.to_write || s.written) {
4726                         set_bit(STRIPE_HANDLE, &sh->state);
4727                         goto finish;
4728                 }
4729                 /* There is nothing for the blocked_rdev to block */
4730                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
4731                 s.blocked_rdev = NULL;
4732         }
4733
4734         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
4735                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
4736                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
4737         }
4738
4739         pr_debug("locked=%d uptodate=%d to_read=%d"
4740                " to_write=%d failed=%d failed_num=%d,%d\n",
4741                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
4742                s.failed_num[0], s.failed_num[1]);
4743         /*
4744          * check if the array has lost more than max_degraded devices and,
4745          * if so, some requests might need to be failed.
4746          *
4747          * When journal device failed (log_failed), we will only process
4748          * the stripe if there is data need write to raid disks
4749          */
4750         if (s.failed > conf->max_degraded ||
4751             (s.log_failed && s.injournal == 0)) {
4752                 sh->check_state = 0;
4753                 sh->reconstruct_state = 0;
4754                 break_stripe_batch_list(sh, 0);
4755                 if (s.to_read+s.to_write+s.written)
4756                         handle_failed_stripe(conf, sh, &s, disks);
4757                 if (s.syncing + s.replacing)
4758                         handle_failed_sync(conf, sh, &s);
4759         }
4760
4761         /* Now we check to see if any write operations have recently
4762          * completed
4763          */
4764         prexor = 0;
4765         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
4766                 prexor = 1;
4767         if (sh->reconstruct_state == reconstruct_state_drain_result ||
4768             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
4769                 sh->reconstruct_state = reconstruct_state_idle;
4770
4771                 /* All the 'written' buffers and the parity block are ready to
4772                  * be written back to disk
4773                  */
4774                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
4775                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
4776                 BUG_ON(sh->qd_idx >= 0 &&
4777                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
4778                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
4779                 for (i = disks; i--; ) {
4780                         struct r5dev *dev = &sh->dev[i];
4781                         if (test_bit(R5_LOCKED, &dev->flags) &&
4782                                 (i == sh->pd_idx || i == sh->qd_idx ||
4783                                  dev->written || test_bit(R5_InJournal,
4784                                                           &dev->flags))) {
4785                                 pr_debug("Writing block %d\n", i);
4786                                 set_bit(R5_Wantwrite, &dev->flags);
4787                                 if (prexor)
4788                                         continue;
4789                                 if (s.failed > 1)
4790                                         continue;
4791                                 if (!test_bit(R5_Insync, &dev->flags) ||
4792                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
4793                                      s.failed == 0))
4794                                         set_bit(STRIPE_INSYNC, &sh->state);
4795                         }
4796                 }
4797                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4798                         s.dec_preread_active = 1;
4799         }
4800
4801         /*
4802          * might be able to return some write requests if the parity blocks
4803          * are safe, or on a failed drive
4804          */
4805         pdev = &sh->dev[sh->pd_idx];
4806         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
4807                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
4808         qdev = &sh->dev[sh->qd_idx];
4809         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
4810                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
4811                 || conf->level < 6;
4812
4813         if (s.written &&
4814             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
4815                              && !test_bit(R5_LOCKED, &pdev->flags)
4816                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
4817                                  test_bit(R5_Discard, &pdev->flags))))) &&
4818             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
4819                              && !test_bit(R5_LOCKED, &qdev->flags)
4820                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
4821                                  test_bit(R5_Discard, &qdev->flags))))))
4822                 handle_stripe_clean_event(conf, sh, disks);
4823
4824         if (s.just_cached)
4825                 r5c_handle_cached_data_endio(conf, sh, disks);
4826         log_stripe_write_finished(sh);
4827
4828         /* Now we might consider reading some blocks, either to check/generate
4829          * parity, or to satisfy requests
4830          * or to load a block that is being partially written.
4831          */
4832         if (s.to_read || s.non_overwrite
4833             || (s.to_write && s.failed)
4834             || (s.syncing && (s.uptodate + s.compute < disks))
4835             || s.replacing
4836             || s.expanding)
4837                 handle_stripe_fill(sh, &s, disks);
4838
4839         /*
4840          * When the stripe finishes full journal write cycle (write to journal
4841          * and raid disk), this is the clean up procedure so it is ready for
4842          * next operation.
4843          */
4844         r5c_finish_stripe_write_out(conf, sh, &s);
4845
4846         /*
4847          * Now to consider new write requests, cache write back and what else,
4848          * if anything should be read.  We do not handle new writes when:
4849          * 1/ A 'write' operation (copy+xor) is already in flight.
4850          * 2/ A 'check' operation is in flight, as it may clobber the parity
4851          *    block.
4852          * 3/ A r5c cache log write is in flight.
4853          */
4854
4855         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
4856                 if (!r5c_is_writeback(conf->log)) {
4857                         if (s.to_write)
4858                                 handle_stripe_dirtying(conf, sh, &s, disks);
4859                 } else { /* write back cache */
4860                         int ret = 0;
4861
4862                         /* First, try handle writes in caching phase */
4863                         if (s.to_write)
4864                                 ret = r5c_try_caching_write(conf, sh, &s,
4865                                                             disks);
4866                         /*
4867                          * If caching phase failed: ret == -EAGAIN
4868                          *    OR
4869                          * stripe under reclaim: !caching && injournal
4870                          *
4871                          * fall back to handle_stripe_dirtying()
4872                          */
4873                         if (ret == -EAGAIN ||
4874                             /* stripe under reclaim: !caching && injournal */
4875                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
4876                              s.injournal > 0)) {
4877                                 ret = handle_stripe_dirtying(conf, sh, &s,
4878                                                              disks);
4879                                 if (ret == -EAGAIN)
4880                                         goto finish;
4881                         }
4882                 }
4883         }
4884
4885         /* maybe we need to check and possibly fix the parity for this stripe
4886          * Any reads will already have been scheduled, so we just see if enough
4887          * data is available.  The parity check is held off while parity
4888          * dependent operations are in flight.
4889          */
4890         if (sh->check_state ||
4891             (s.syncing && s.locked == 0 &&
4892              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4893              !test_bit(STRIPE_INSYNC, &sh->state))) {
4894                 if (conf->level == 6)
4895                         handle_parity_checks6(conf, sh, &s, disks);
4896                 else
4897                         handle_parity_checks5(conf, sh, &s, disks);
4898         }
4899
4900         if ((s.replacing || s.syncing) && s.locked == 0
4901             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
4902             && !test_bit(STRIPE_REPLACED, &sh->state)) {
4903                 /* Write out to replacement devices where possible */
4904                 for (i = 0; i < conf->raid_disks; i++)
4905                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
4906                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
4907                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
4908                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
4909                                 s.locked++;
4910                         }
4911                 if (s.replacing)
4912                         set_bit(STRIPE_INSYNC, &sh->state);
4913                 set_bit(STRIPE_REPLACED, &sh->state);
4914         }
4915         if ((s.syncing || s.replacing) && s.locked == 0 &&
4916             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4917             test_bit(STRIPE_INSYNC, &sh->state)) {
4918                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4919                 clear_bit(STRIPE_SYNCING, &sh->state);
4920                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
4921                         wake_up(&conf->wait_for_overlap);
4922         }
4923
4924         /* If the failed drives are just a ReadError, then we might need
4925          * to progress the repair/check process
4926          */
4927         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
4928                 for (i = 0; i < s.failed; i++) {
4929                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
4930                         if (test_bit(R5_ReadError, &dev->flags)
4931                             && !test_bit(R5_LOCKED, &dev->flags)
4932                             && test_bit(R5_UPTODATE, &dev->flags)
4933                                 ) {
4934                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
4935                                         set_bit(R5_Wantwrite, &dev->flags);
4936                                         set_bit(R5_ReWrite, &dev->flags);
4937                                         set_bit(R5_LOCKED, &dev->flags);
4938                                         s.locked++;
4939                                 } else {
4940                                         /* let's read it back */
4941                                         set_bit(R5_Wantread, &dev->flags);
4942                                         set_bit(R5_LOCKED, &dev->flags);
4943                                         s.locked++;
4944                                 }
4945                         }
4946                 }
4947
4948         /* Finish reconstruct operations initiated by the expansion process */
4949         if (sh->reconstruct_state == reconstruct_state_result) {
4950                 struct stripe_head *sh_src
4951                         = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
4952                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
4953                         /* sh cannot be written until sh_src has been read.
4954                          * so arrange for sh to be delayed a little
4955                          */
4956                         set_bit(STRIPE_DELAYED, &sh->state);
4957                         set_bit(STRIPE_HANDLE, &sh->state);
4958                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
4959                                               &sh_src->state))
4960                                 atomic_inc(&conf->preread_active_stripes);
4961                         raid5_release_stripe(sh_src);
4962                         goto finish;
4963                 }
4964                 if (sh_src)
4965                         raid5_release_stripe(sh_src);
4966
4967                 sh->reconstruct_state = reconstruct_state_idle;
4968                 clear_bit(STRIPE_EXPANDING, &sh->state);
4969                 for (i = conf->raid_disks; i--; ) {
4970                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
4971                         set_bit(R5_LOCKED, &sh->dev[i].flags);
4972                         s.locked++;
4973                 }
4974         }
4975
4976         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
4977             !sh->reconstruct_state) {
4978                 /* Need to write out all blocks after computing parity */
4979                 sh->disks = conf->raid_disks;
4980                 stripe_set_idx(sh->sector, conf, 0, sh);
4981                 schedule_reconstruction(sh, &s, 1, 1);
4982         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
4983                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
4984                 atomic_dec(&conf->reshape_stripes);
4985                 wake_up(&conf->wait_for_overlap);
4986                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4987         }
4988
4989         if (s.expanding && s.locked == 0 &&
4990             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
4991                 handle_stripe_expansion(conf, sh);
4992
4993 finish:
4994         /* wait for this device to become unblocked */
4995         if (unlikely(s.blocked_rdev)) {
4996                 if (conf->mddev->external)
4997                         md_wait_for_blocked_rdev(s.blocked_rdev,
4998                                                  conf->mddev);
4999                 else
5000                         /* Internal metadata will immediately
5001                          * be written by raid5d, so we don't
5002                          * need to wait here.
5003                          */
5004                         rdev_dec_pending(s.blocked_rdev,
5005                                          conf->mddev);
5006         }
5007
5008         if (s.handle_bad_blocks)
5009                 for (i = disks; i--; ) {
5010                         struct md_rdev *rdev;
5011                         struct r5dev *dev = &sh->dev[i];
5012                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5013                                 /* We own a safe reference to the rdev */
5014                                 rdev = conf->disks[i].rdev;
5015                                 if (!rdev_set_badblocks(rdev, sh->sector,
5016                                                         STRIPE_SECTORS, 0))
5017                                         md_error(conf->mddev, rdev);
5018                                 rdev_dec_pending(rdev, conf->mddev);
5019                         }
5020                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5021                                 rdev = conf->disks[i].rdev;
5022                                 rdev_clear_badblocks(rdev, sh->sector,
5023                                                      STRIPE_SECTORS, 0);
5024                                 rdev_dec_pending(rdev, conf->mddev);
5025                         }
5026                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5027                                 rdev = conf->disks[i].replacement;
5028                                 if (!rdev)
5029                                         /* rdev have been moved down */
5030                                         rdev = conf->disks[i].rdev;
5031                                 rdev_clear_badblocks(rdev, sh->sector,
5032                                                      STRIPE_SECTORS, 0);
5033                                 rdev_dec_pending(rdev, conf->mddev);
5034                         }
5035                 }
5036
5037         if (s.ops_request)
5038                 raid_run_ops(sh, s.ops_request);
5039
5040         ops_run_io(sh, &s);
5041
5042         if (s.dec_preread_active) {
5043                 /* We delay this until after ops_run_io so that if make_request
5044                  * is waiting on a flush, it won't continue until the writes
5045                  * have actually been submitted.
5046                  */
5047                 atomic_dec(&conf->preread_active_stripes);
5048                 if (atomic_read(&conf->preread_active_stripes) <
5049                     IO_THRESHOLD)
5050                         md_wakeup_thread(conf->mddev->thread);
5051         }
5052
5053         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5054 }
5055
5056 static void raid5_activate_delayed(struct r5conf *conf)
5057 {
5058         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5059                 while (!list_empty(&conf->delayed_list)) {
5060                         struct list_head *l = conf->delayed_list.next;
5061                         struct stripe_head *sh;
5062                         sh = list_entry(l, struct stripe_head, lru);
5063                         list_del_init(l);
5064                         clear_bit(STRIPE_DELAYED, &sh->state);
5065                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5066                                 atomic_inc(&conf->preread_active_stripes);
5067                         list_add_tail(&sh->lru, &conf->hold_list);
5068                         raid5_wakeup_stripe_thread(sh);
5069                 }
5070         }
5071 }
5072
5073 static void activate_bit_delay(struct r5conf *conf,
5074         struct list_head *temp_inactive_list)
5075 {
5076         /* device_lock is held */
5077         struct list_head head;
5078         list_add(&head, &conf->bitmap_list);
5079         list_del_init(&conf->bitmap_list);
5080         while (!list_empty(&head)) {
5081                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5082                 int hash;
5083                 list_del_init(&sh->lru);
5084                 atomic_inc(&sh->count);
5085                 hash = sh->hash_lock_index;
5086                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5087         }
5088 }
5089
5090 static int raid5_congested(struct mddev *mddev, int bits)
5091 {
5092         struct r5conf *conf = mddev->private;
5093
5094         /* No difference between reads and writes.  Just check
5095          * how busy the stripe_cache is
5096          */
5097
5098         if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
5099                 return 1;
5100
5101         /* Also checks whether there is pressure on r5cache log space */
5102         if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
5103                 return 1;
5104         if (conf->quiesce)
5105                 return 1;
5106         if (atomic_read(&conf->empty_inactive_list_nr))
5107                 return 1;
5108
5109         return 0;
5110 }
5111
5112 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5113 {
5114         struct r5conf *conf = mddev->private;
5115         sector_t sector = bio->bi_iter.bi_sector;
5116         unsigned int chunk_sectors;
5117         unsigned int bio_sectors = bio_sectors(bio);
5118
5119         WARN_ON_ONCE(bio->bi_partno);
5120
5121         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5122         return  chunk_sectors >=
5123                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5124 }
5125
5126 /*
5127  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5128  *  later sampled by raid5d.
5129  */
5130 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5131 {
5132         unsigned long flags;
5133
5134         spin_lock_irqsave(&conf->device_lock, flags);
5135
5136         bi->bi_next = conf->retry_read_aligned_list;
5137         conf->retry_read_aligned_list = bi;
5138
5139         spin_unlock_irqrestore(&conf->device_lock, flags);
5140         md_wakeup_thread(conf->mddev->thread);
5141 }
5142
5143 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5144                                          unsigned int *offset)
5145 {
5146         struct bio *bi;
5147
5148         bi = conf->retry_read_aligned;
5149         if (bi) {
5150                 *offset = conf->retry_read_offset;
5151                 conf->retry_read_aligned = NULL;
5152                 return bi;
5153         }
5154         bi = conf->retry_read_aligned_list;
5155         if(bi) {
5156                 conf->retry_read_aligned_list = bi->bi_next;
5157                 bi->bi_next = NULL;
5158                 *offset = 0;
5159         }
5160
5161         return bi;
5162 }
5163
5164 /*
5165  *  The "raid5_align_endio" should check if the read succeeded and if it
5166  *  did, call bio_endio on the original bio (having bio_put the new bio
5167  *  first).
5168  *  If the read failed..
5169  */
5170 static void raid5_align_endio(struct bio *bi)
5171 {
5172         struct bio* raid_bi  = bi->bi_private;
5173         struct mddev *mddev;
5174         struct r5conf *conf;
5175         struct md_rdev *rdev;
5176         blk_status_t error = bi->bi_status;
5177
5178         bio_put(bi);
5179
5180         rdev = (void*)raid_bi->bi_next;
5181         raid_bi->bi_next = NULL;
5182         mddev = rdev->mddev;
5183         conf = mddev->private;
5184
5185         rdev_dec_pending(rdev, conf->mddev);
5186
5187         if (!error) {
5188                 bio_endio(raid_bi);
5189                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5190                         wake_up(&conf->wait_for_quiescent);
5191                 return;
5192         }
5193
5194         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5195
5196         add_bio_to_retry(raid_bi, conf);
5197 }
5198
5199 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5200 {
5201         struct r5conf *conf = mddev->private;
5202         int dd_idx;
5203         struct bio* align_bi;
5204         struct md_rdev *rdev;
5205         sector_t end_sector;
5206
5207         if (!in_chunk_boundary(mddev, raid_bio)) {
5208                 pr_debug("%s: non aligned\n", __func__);
5209                 return 0;
5210         }
5211         /*
5212          * use bio_clone_fast to make a copy of the bio
5213          */
5214         align_bi = bio_clone_fast(raid_bio, GFP_NOIO, mddev->bio_set);
5215         if (!align_bi)
5216                 return 0;
5217         /*
5218          *   set bi_end_io to a new function, and set bi_private to the
5219          *     original bio.
5220          */
5221         align_bi->bi_end_io  = raid5_align_endio;
5222         align_bi->bi_private = raid_bio;
5223         /*
5224          *      compute position
5225          */
5226         align_bi->bi_iter.bi_sector =
5227                 raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
5228                                      0, &dd_idx, NULL);
5229
5230         end_sector = bio_end_sector(align_bi);
5231         rcu_read_lock();
5232         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5233         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5234             rdev->recovery_offset < end_sector) {
5235                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5236                 if (rdev &&
5237                     (test_bit(Faulty, &rdev->flags) ||
5238                     !(test_bit(In_sync, &rdev->flags) ||
5239                       rdev->recovery_offset >= end_sector)))
5240                         rdev = NULL;
5241         }
5242
5243         if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
5244                 rcu_read_unlock();
5245                 bio_put(align_bi);
5246                 return 0;
5247         }
5248
5249         if (rdev) {
5250                 sector_t first_bad;
5251                 int bad_sectors;
5252
5253                 atomic_inc(&rdev->nr_pending);
5254                 rcu_read_unlock();
5255                 raid_bio->bi_next = (void*)rdev;
5256                 bio_set_dev(align_bi, rdev->bdev);
5257                 bio_clear_flag(align_bi, BIO_SEG_VALID);
5258
5259                 if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
5260                                 bio_sectors(align_bi),
5261                                 &first_bad, &bad_sectors)) {
5262                         bio_put(align_bi);
5263                         rdev_dec_pending(rdev, mddev);
5264                         return 0;
5265                 }
5266
5267                 /* No reshape active, so we can trust rdev->data_offset */
5268                 align_bi->bi_iter.bi_sector += rdev->data_offset;
5269
5270                 spin_lock_irq(&conf->device_lock);
5271                 wait_event_lock_irq(conf->wait_for_quiescent,
5272                                     conf->quiesce == 0,
5273                                     conf->device_lock);
5274                 atomic_inc(&conf->active_aligned_reads);
5275                 spin_unlock_irq(&conf->device_lock);
5276
5277                 if (mddev->gendisk)
5278                         trace_block_bio_remap(align_bi->bi_disk->queue,
5279                                               align_bi, disk_devt(mddev->gendisk),
5280                                               raid_bio->bi_iter.bi_sector);
5281                 generic_make_request(align_bi);
5282                 return 1;
5283         } else {
5284                 rcu_read_unlock();
5285                 bio_put(align_bi);
5286                 return 0;
5287         }
5288 }
5289
5290 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5291 {
5292         struct bio *split;
5293         sector_t sector = raid_bio->bi_iter.bi_sector;
5294         unsigned chunk_sects = mddev->chunk_sectors;
5295         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5296
5297         if (sectors < bio_sectors(raid_bio)) {
5298                 struct r5conf *conf = mddev->private;
5299                 split = bio_split(raid_bio, sectors, GFP_NOIO, conf->bio_split);
5300                 bio_chain(split, raid_bio);
5301                 generic_make_request(raid_bio);
5302                 raid_bio = split;
5303         }
5304
5305         if (!raid5_read_one_chunk(mddev, raid_bio))
5306                 return raid_bio;
5307
5308         return NULL;
5309 }
5310
5311 /* __get_priority_stripe - get the next stripe to process
5312  *
5313  * Full stripe writes are allowed to pass preread active stripes up until
5314  * the bypass_threshold is exceeded.  In general the bypass_count
5315  * increments when the handle_list is handled before the hold_list; however, it
5316  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5317  * stripe with in flight i/o.  The bypass_count will be reset when the
5318  * head of the hold_list has changed, i.e. the head was promoted to the
5319  * handle_list.
5320  */
5321 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5322 {
5323         struct stripe_head *sh, *tmp;
5324         struct list_head *handle_list = NULL;
5325         struct r5worker_group *wg;
5326         bool second_try = !r5c_is_writeback(conf->log) &&
5327                 !r5l_log_disk_error(conf);
5328         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5329                 r5l_log_disk_error(conf);
5330
5331 again:
5332         wg = NULL;
5333         sh = NULL;
5334         if (conf->worker_cnt_per_group == 0) {
5335                 handle_list = try_loprio ? &conf->loprio_list :
5336                                         &conf->handle_list;
5337         } else if (group != ANY_GROUP) {
5338                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5339                                 &conf->worker_groups[group].handle_list;
5340                 wg = &conf->worker_groups[group];
5341         } else {
5342                 int i;
5343                 for (i = 0; i < conf->group_cnt; i++) {
5344                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5345                                 &conf->worker_groups[i].handle_list;
5346                         wg = &conf->worker_groups[i];
5347                         if (!list_empty(handle_list))
5348                                 break;
5349                 }
5350         }
5351
5352         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5353                   __func__,
5354                   list_empty(handle_list) ? "empty" : "busy",
5355                   list_empty(&conf->hold_list) ? "empty" : "busy",
5356                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5357
5358         if (!list_empty(handle_list)) {
5359                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5360
5361                 if (list_empty(&conf->hold_list))
5362                         conf->bypass_count = 0;
5363                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5364                         if (conf->hold_list.next == conf->last_hold)
5365                                 conf->bypass_count++;
5366                         else {
5367                                 conf->last_hold = conf->hold_list.next;
5368                                 conf->bypass_count -= conf->bypass_threshold;
5369                                 if (conf->bypass_count < 0)
5370                                         conf->bypass_count = 0;
5371                         }
5372                 }
5373         } else if (!list_empty(&conf->hold_list) &&
5374                    ((conf->bypass_threshold &&
5375                      conf->bypass_count > conf->bypass_threshold) ||
5376                     atomic_read(&conf->pending_full_writes) == 0)) {
5377
5378                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5379                         if (conf->worker_cnt_per_group == 0 ||
5380                             group == ANY_GROUP ||
5381                             !cpu_online(tmp->cpu) ||
5382                             cpu_to_group(tmp->cpu) == group) {
5383                                 sh = tmp;
5384                                 break;
5385                         }
5386                 }
5387
5388                 if (sh) {
5389                         conf->bypass_count -= conf->bypass_threshold;
5390                         if (conf->bypass_count < 0)
5391                                 conf->bypass_count = 0;
5392                 }
5393                 wg = NULL;
5394         }
5395
5396         if (!sh) {
5397                 if (second_try)
5398                         return NULL;
5399                 second_try = true;
5400                 try_loprio = !try_loprio;
5401                 goto again;
5402         }
5403
5404         if (wg) {
5405                 wg->stripes_cnt--;
5406                 sh->group = NULL;
5407         }
5408         list_del_init(&sh->lru);
5409         BUG_ON(atomic_inc_return(&sh->count) != 1);
5410         return sh;
5411 }
5412
5413 struct raid5_plug_cb {
5414         struct blk_plug_cb      cb;
5415         struct list_head        list;
5416         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5417 };
5418
5419 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5420 {
5421         struct raid5_plug_cb *cb = container_of(
5422                 blk_cb, struct raid5_plug_cb, cb);
5423         struct stripe_head *sh;
5424         struct mddev *mddev = cb->cb.data;
5425         struct r5conf *conf = mddev->private;
5426         int cnt = 0;
5427         int hash;
5428
5429         if (cb->list.next && !list_empty(&cb->list)) {
5430                 spin_lock_irq(&conf->device_lock);
5431                 while (!list_empty(&cb->list)) {
5432                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5433                         list_del_init(&sh->lru);
5434                         /*
5435                          * avoid race release_stripe_plug() sees
5436                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5437                          * is still in our list
5438                          */
5439                         smp_mb__before_atomic();
5440                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5441                         /*
5442                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5443                          * case, the count is always > 1 here
5444                          */
5445                         hash = sh->hash_lock_index;
5446                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5447                         cnt++;
5448                 }
5449                 spin_unlock_irq(&conf->device_lock);
5450         }
5451         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5452                                      NR_STRIPE_HASH_LOCKS);
5453         if (mddev->queue)
5454                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5455         kfree(cb);
5456 }
5457
5458 static void release_stripe_plug(struct mddev *mddev,
5459                                 struct stripe_head *sh)
5460 {
5461         struct blk_plug_cb *blk_cb = blk_check_plugged(
5462                 raid5_unplug, mddev,
5463                 sizeof(struct raid5_plug_cb));
5464         struct raid5_plug_cb *cb;
5465
5466         if (!blk_cb) {
5467                 raid5_release_stripe(sh);
5468                 return;
5469         }
5470
5471         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5472
5473         if (cb->list.next == NULL) {
5474                 int i;
5475                 INIT_LIST_HEAD(&cb->list);
5476                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5477                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5478         }
5479
5480         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5481                 list_add_tail(&sh->lru, &cb->list);
5482         else
5483                 raid5_release_stripe(sh);
5484 }
5485
5486 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5487 {
5488         struct r5conf *conf = mddev->private;
5489         sector_t logical_sector, last_sector;
5490         struct stripe_head *sh;
5491         int stripe_sectors;
5492
5493         if (mddev->reshape_position != MaxSector)
5494                 /* Skip discard while reshape is happening */
5495                 return;
5496
5497         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5498         last_sector = bi->bi_iter.bi_sector + (bi->bi_iter.bi_size>>9);
5499
5500         bi->bi_next = NULL;
5501
5502         stripe_sectors = conf->chunk_sectors *
5503                 (conf->raid_disks - conf->max_degraded);
5504         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5505                                                stripe_sectors);
5506         sector_div(last_sector, stripe_sectors);
5507
5508         logical_sector *= conf->chunk_sectors;
5509         last_sector *= conf->chunk_sectors;
5510
5511         for (; logical_sector < last_sector;
5512              logical_sector += STRIPE_SECTORS) {
5513                 DEFINE_WAIT(w);
5514                 int d;
5515         again:
5516                 sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5517                 prepare_to_wait(&conf->wait_for_overlap, &w,
5518                                 TASK_UNINTERRUPTIBLE);
5519                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5520                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5521                         raid5_release_stripe(sh);
5522                         schedule();
5523                         goto again;
5524                 }
5525                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5526                 spin_lock_irq(&sh->stripe_lock);
5527                 for (d = 0; d < conf->raid_disks; d++) {
5528                         if (d == sh->pd_idx || d == sh->qd_idx)
5529                                 continue;
5530                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5531                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5532                                 spin_unlock_irq(&sh->stripe_lock);
5533                                 raid5_release_stripe(sh);
5534                                 schedule();
5535                                 goto again;
5536                         }
5537                 }
5538                 set_bit(STRIPE_DISCARD, &sh->state);
5539                 finish_wait(&conf->wait_for_overlap, &w);
5540                 sh->overwrite_disks = 0;
5541                 for (d = 0; d < conf->raid_disks; d++) {
5542                         if (d == sh->pd_idx || d == sh->qd_idx)
5543                                 continue;
5544                         sh->dev[d].towrite = bi;
5545                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5546                         bio_inc_remaining(bi);
5547                         md_write_inc(mddev, bi);
5548                         sh->overwrite_disks++;
5549                 }
5550                 spin_unlock_irq(&sh->stripe_lock);
5551                 if (conf->mddev->bitmap) {
5552                         for (d = 0;
5553                              d < conf->raid_disks - conf->max_degraded;
5554                              d++)
5555                                 bitmap_startwrite(mddev->bitmap,
5556                                                   sh->sector,
5557                                                   STRIPE_SECTORS,
5558                                                   0);
5559                         sh->bm_seq = conf->seq_flush + 1;
5560                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5561                 }
5562
5563                 set_bit(STRIPE_HANDLE, &sh->state);
5564                 clear_bit(STRIPE_DELAYED, &sh->state);
5565                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5566                         atomic_inc(&conf->preread_active_stripes);
5567                 release_stripe_plug(mddev, sh);
5568         }
5569
5570         bio_endio(bi);
5571 }
5572
5573 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
5574 {
5575         struct r5conf *conf = mddev->private;
5576         int dd_idx;
5577         sector_t new_sector;
5578         sector_t logical_sector, last_sector;
5579         struct stripe_head *sh;
5580         const int rw = bio_data_dir(bi);
5581         DEFINE_WAIT(w);
5582         bool do_prepare;
5583         bool do_flush = false;
5584
5585         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
5586                 int ret = r5l_handle_flush_request(conf->log, bi);
5587
5588                 if (ret == 0)
5589                         return true;
5590                 if (ret == -ENODEV) {
5591                         md_flush_request(mddev, bi);
5592                         return true;
5593                 }
5594                 /* ret == -EAGAIN, fallback */
5595                 /*
5596                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
5597                  * we need to flush journal device
5598                  */
5599                 do_flush = bi->bi_opf & REQ_PREFLUSH;
5600         }
5601
5602         if (!md_write_start(mddev, bi))
5603                 return false;
5604         /*
5605          * If array is degraded, better not do chunk aligned read because
5606          * later we might have to read it again in order to reconstruct
5607          * data on failed drives.
5608          */
5609         if (rw == READ && mddev->degraded == 0 &&
5610             mddev->reshape_position == MaxSector) {
5611                 bi = chunk_aligned_read(mddev, bi);
5612                 if (!bi)
5613                         return true;
5614         }
5615
5616         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
5617                 make_discard_request(mddev, bi);
5618                 md_write_end(mddev);
5619                 return true;
5620         }
5621
5622         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5623         last_sector = bio_end_sector(bi);
5624         bi->bi_next = NULL;
5625
5626         prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
5627         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
5628                 int previous;
5629                 int seq;
5630
5631                 do_prepare = false;
5632         retry:
5633                 seq = read_seqcount_begin(&conf->gen_lock);
5634                 previous = 0;
5635                 if (do_prepare)
5636                         prepare_to_wait(&conf->wait_for_overlap, &w,
5637                                 TASK_UNINTERRUPTIBLE);
5638                 if (unlikely(conf->reshape_progress != MaxSector)) {
5639                         /* spinlock is needed as reshape_progress may be
5640                          * 64bit on a 32bit platform, and so it might be
5641                          * possible to see a half-updated value
5642                          * Of course reshape_progress could change after
5643                          * the lock is dropped, so once we get a reference
5644                          * to the stripe that we think it is, we will have
5645                          * to check again.
5646                          */
5647                         spin_lock_irq(&conf->device_lock);
5648                         if (mddev->reshape_backwards
5649                             ? logical_sector < conf->reshape_progress
5650                             : logical_sector >= conf->reshape_progress) {
5651                                 previous = 1;
5652                         } else {
5653                                 if (mddev->reshape_backwards
5654                                     ? logical_sector < conf->reshape_safe
5655                                     : logical_sector >= conf->reshape_safe) {
5656                                         spin_unlock_irq(&conf->device_lock);
5657                                         schedule();
5658                                         do_prepare = true;
5659                                         goto retry;
5660                                 }
5661                         }
5662                         spin_unlock_irq(&conf->device_lock);
5663                 }
5664
5665                 new_sector = raid5_compute_sector(conf, logical_sector,
5666                                                   previous,
5667                                                   &dd_idx, NULL);
5668                 pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
5669                         (unsigned long long)new_sector,
5670                         (unsigned long long)logical_sector);
5671
5672                 sh = raid5_get_active_stripe(conf, new_sector, previous,
5673                                        (bi->bi_opf & REQ_RAHEAD), 0);
5674                 if (sh) {
5675                         if (unlikely(previous)) {
5676                                 /* expansion might have moved on while waiting for a
5677                                  * stripe, so we must do the range check again.
5678                                  * Expansion could still move past after this
5679                                  * test, but as we are holding a reference to
5680                                  * 'sh', we know that if that happens,
5681                                  *  STRIPE_EXPANDING will get set and the expansion
5682                                  * won't proceed until we finish with the stripe.
5683                                  */
5684                                 int must_retry = 0;
5685                                 spin_lock_irq(&conf->device_lock);
5686                                 if (mddev->reshape_backwards
5687                                     ? logical_sector >= conf->reshape_progress
5688                                     : logical_sector < conf->reshape_progress)
5689                                         /* mismatch, need to try again */
5690                                         must_retry = 1;
5691                                 spin_unlock_irq(&conf->device_lock);
5692                                 if (must_retry) {
5693                                         raid5_release_stripe(sh);
5694                                         schedule();
5695                                         do_prepare = true;
5696                                         goto retry;
5697                                 }
5698                         }
5699                         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5700                                 /* Might have got the wrong stripe_head
5701                                  * by accident
5702                                  */
5703                                 raid5_release_stripe(sh);
5704                                 goto retry;
5705                         }
5706
5707                         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5708                             !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
5709                                 /* Stripe is busy expanding or
5710                                  * add failed due to overlap.  Flush everything
5711                                  * and wait a while
5712                                  */
5713                                 md_wakeup_thread(mddev->thread);
5714                                 raid5_release_stripe(sh);
5715                                 schedule();
5716                                 do_prepare = true;
5717                                 goto retry;
5718                         }
5719                         if (do_flush) {
5720                                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5721                                 /* we only need flush for one stripe */
5722                                 do_flush = false;
5723                         }
5724
5725                         if (!sh->batch_head || sh == sh->batch_head)
5726                                 set_bit(STRIPE_HANDLE, &sh->state);
5727                         clear_bit(STRIPE_DELAYED, &sh->state);
5728                         if ((!sh->batch_head || sh == sh->batch_head) &&
5729                             (bi->bi_opf & REQ_SYNC) &&
5730                             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5731                                 atomic_inc(&conf->preread_active_stripes);
5732                         release_stripe_plug(mddev, sh);
5733                 } else {
5734                         /* cannot get stripe for read-ahead, just give-up */
5735                         bi->bi_status = BLK_STS_IOERR;
5736                         break;
5737                 }
5738         }
5739         finish_wait(&conf->wait_for_overlap, &w);
5740
5741         if (rw == WRITE)
5742                 md_write_end(mddev);
5743         bio_endio(bi);
5744         return true;
5745 }
5746
5747 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
5748
5749 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
5750 {
5751         /* reshaping is quite different to recovery/resync so it is
5752          * handled quite separately ... here.
5753          *
5754          * On each call to sync_request, we gather one chunk worth of
5755          * destination stripes and flag them as expanding.
5756          * Then we find all the source stripes and request reads.
5757          * As the reads complete, handle_stripe will copy the data
5758          * into the destination stripe and release that stripe.
5759          */
5760         struct r5conf *conf = mddev->private;
5761         struct stripe_head *sh;
5762         sector_t first_sector, last_sector;
5763         int raid_disks = conf->previous_raid_disks;
5764         int data_disks = raid_disks - conf->max_degraded;
5765         int new_data_disks = conf->raid_disks - conf->max_degraded;
5766         int i;
5767         int dd_idx;
5768         sector_t writepos, readpos, safepos;
5769         sector_t stripe_addr;
5770         int reshape_sectors;
5771         struct list_head stripes;
5772         sector_t retn;
5773
5774         if (sector_nr == 0) {
5775                 /* If restarting in the middle, skip the initial sectors */
5776                 if (mddev->reshape_backwards &&
5777                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
5778                         sector_nr = raid5_size(mddev, 0, 0)
5779                                 - conf->reshape_progress;
5780                 } else if (mddev->reshape_backwards &&
5781                            conf->reshape_progress == MaxSector) {
5782                         /* shouldn't happen, but just in case, finish up.*/
5783                         sector_nr = MaxSector;
5784                 } else if (!mddev->reshape_backwards &&
5785                            conf->reshape_progress > 0)
5786                         sector_nr = conf->reshape_progress;
5787                 sector_div(sector_nr, new_data_disks);
5788                 if (sector_nr) {
5789                         mddev->curr_resync_completed = sector_nr;
5790                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5791                         *skipped = 1;
5792                         retn = sector_nr;
5793                         goto finish;
5794                 }
5795         }
5796
5797         /* We need to process a full chunk at a time.
5798          * If old and new chunk sizes differ, we need to process the
5799          * largest of these
5800          */
5801
5802         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
5803
5804         /* We update the metadata at least every 10 seconds, or when
5805          * the data about to be copied would over-write the source of
5806          * the data at the front of the range.  i.e. one new_stripe
5807          * along from reshape_progress new_maps to after where
5808          * reshape_safe old_maps to
5809          */
5810         writepos = conf->reshape_progress;
5811         sector_div(writepos, new_data_disks);
5812         readpos = conf->reshape_progress;
5813         sector_div(readpos, data_disks);
5814         safepos = conf->reshape_safe;
5815         sector_div(safepos, data_disks);
5816         if (mddev->reshape_backwards) {
5817                 BUG_ON(writepos < reshape_sectors);
5818                 writepos -= reshape_sectors;
5819                 readpos += reshape_sectors;
5820                 safepos += reshape_sectors;
5821         } else {
5822                 writepos += reshape_sectors;
5823                 /* readpos and safepos are worst-case calculations.
5824                  * A negative number is overly pessimistic, and causes
5825                  * obvious problems for unsigned storage.  So clip to 0.
5826                  */
5827                 readpos -= min_t(sector_t, reshape_sectors, readpos);
5828                 safepos -= min_t(sector_t, reshape_sectors, safepos);
5829         }
5830
5831         /* Having calculated the 'writepos' possibly use it
5832          * to set 'stripe_addr' which is where we will write to.
5833          */
5834         if (mddev->reshape_backwards) {
5835                 BUG_ON(conf->reshape_progress == 0);
5836                 stripe_addr = writepos;
5837                 BUG_ON((mddev->dev_sectors &
5838                         ~((sector_t)reshape_sectors - 1))
5839                        - reshape_sectors - stripe_addr
5840                        != sector_nr);
5841         } else {
5842                 BUG_ON(writepos != sector_nr + reshape_sectors);
5843                 stripe_addr = sector_nr;
5844         }
5845
5846         /* 'writepos' is the most advanced device address we might write.
5847          * 'readpos' is the least advanced device address we might read.
5848          * 'safepos' is the least address recorded in the metadata as having
5849          *     been reshaped.
5850          * If there is a min_offset_diff, these are adjusted either by
5851          * increasing the safepos/readpos if diff is negative, or
5852          * increasing writepos if diff is positive.
5853          * If 'readpos' is then behind 'writepos', there is no way that we can
5854          * ensure safety in the face of a crash - that must be done by userspace
5855          * making a backup of the data.  So in that case there is no particular
5856          * rush to update metadata.
5857          * Otherwise if 'safepos' is behind 'writepos', then we really need to
5858          * update the metadata to advance 'safepos' to match 'readpos' so that
5859          * we can be safe in the event of a crash.
5860          * So we insist on updating metadata if safepos is behind writepos and
5861          * readpos is beyond writepos.
5862          * In any case, update the metadata every 10 seconds.
5863          * Maybe that number should be configurable, but I'm not sure it is
5864          * worth it.... maybe it could be a multiple of safemode_delay???
5865          */
5866         if (conf->min_offset_diff < 0) {
5867                 safepos += -conf->min_offset_diff;
5868                 readpos += -conf->min_offset_diff;
5869         } else
5870                 writepos += conf->min_offset_diff;
5871
5872         if ((mddev->reshape_backwards
5873              ? (safepos > writepos && readpos < writepos)
5874              : (safepos < writepos && readpos > writepos)) ||
5875             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
5876                 /* Cannot proceed until we've updated the superblock... */
5877                 wait_event(conf->wait_for_overlap,
5878                            atomic_read(&conf->reshape_stripes)==0
5879                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5880                 if (atomic_read(&conf->reshape_stripes) != 0)
5881                         return 0;
5882                 mddev->reshape_position = conf->reshape_progress;
5883                 mddev->curr_resync_completed = sector_nr;
5884                 conf->reshape_checkpoint = jiffies;
5885                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5886                 md_wakeup_thread(mddev->thread);
5887                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
5888                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5889                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5890                         return 0;
5891                 spin_lock_irq(&conf->device_lock);
5892                 conf->reshape_safe = mddev->reshape_position;
5893                 spin_unlock_irq(&conf->device_lock);
5894                 wake_up(&conf->wait_for_overlap);
5895                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5896         }
5897
5898         INIT_LIST_HEAD(&stripes);
5899         for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
5900                 int j;
5901                 int skipped_disk = 0;
5902                 sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
5903                 set_bit(STRIPE_EXPANDING, &sh->state);
5904                 atomic_inc(&conf->reshape_stripes);
5905                 /* If any of this stripe is beyond the end of the old
5906                  * array, then we need to zero those blocks
5907                  */
5908                 for (j=sh->disks; j--;) {
5909                         sector_t s;
5910                         if (j == sh->pd_idx)
5911                                 continue;
5912                         if (conf->level == 6 &&
5913                             j == sh->qd_idx)
5914                                 continue;
5915                         s = raid5_compute_blocknr(sh, j, 0);
5916                         if (s < raid5_size(mddev, 0, 0)) {
5917                                 skipped_disk = 1;
5918                                 continue;
5919                         }
5920                         memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
5921                         set_bit(R5_Expanded, &sh->dev[j].flags);
5922                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
5923                 }
5924                 if (!skipped_disk) {
5925                         set_bit(STRIPE_EXPAND_READY, &sh->state);
5926                         set_bit(STRIPE_HANDLE, &sh->state);
5927                 }
5928                 list_add(&sh->lru, &stripes);
5929         }
5930         spin_lock_irq(&conf->device_lock);
5931         if (mddev->reshape_backwards)
5932                 conf->reshape_progress -= reshape_sectors * new_data_disks;
5933         else
5934                 conf->reshape_progress += reshape_sectors * new_data_disks;
5935         spin_unlock_irq(&conf->device_lock);
5936         /* Ok, those stripe are ready. We can start scheduling
5937          * reads on the source stripes.
5938          * The source stripes are determined by mapping the first and last
5939          * block on the destination stripes.
5940          */
5941         first_sector =
5942                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
5943                                      1, &dd_idx, NULL);
5944         last_sector =
5945                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
5946                                             * new_data_disks - 1),
5947                                      1, &dd_idx, NULL);
5948         if (last_sector >= mddev->dev_sectors)
5949                 last_sector = mddev->dev_sectors - 1;
5950         while (first_sector <= last_sector) {
5951                 sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
5952                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
5953                 set_bit(STRIPE_HANDLE, &sh->state);
5954                 raid5_release_stripe(sh);
5955                 first_sector += STRIPE_SECTORS;
5956         }
5957         /* Now that the sources are clearly marked, we can release
5958          * the destination stripes
5959          */
5960         while (!list_empty(&stripes)) {
5961                 sh = list_entry(stripes.next, struct stripe_head, lru);
5962                 list_del_init(&sh->lru);
5963                 raid5_release_stripe(sh);
5964         }
5965         /* If this takes us to the resync_max point where we have to pause,
5966          * then we need to write out the superblock.
5967          */
5968         sector_nr += reshape_sectors;
5969         retn = reshape_sectors;
5970 finish:
5971         if (mddev->curr_resync_completed > mddev->resync_max ||
5972             (sector_nr - mddev->curr_resync_completed) * 2
5973             >= mddev->resync_max - mddev->curr_resync_completed) {
5974                 /* Cannot proceed until we've updated the superblock... */
5975                 wait_event(conf->wait_for_overlap,
5976                            atomic_read(&conf->reshape_stripes) == 0
5977                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5978                 if (atomic_read(&conf->reshape_stripes) != 0)
5979                         goto ret;
5980                 mddev->reshape_position = conf->reshape_progress;
5981                 mddev->curr_resync_completed = sector_nr;
5982                 conf->reshape_checkpoint = jiffies;
5983                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5984                 md_wakeup_thread(mddev->thread);
5985                 wait_event(mddev->sb_wait,
5986                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
5987                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5988                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5989                         goto ret;
5990                 spin_lock_irq(&conf->device_lock);
5991                 conf->reshape_safe = mddev->reshape_position;
5992                 spin_unlock_irq(&conf->device_lock);
5993                 wake_up(&conf->wait_for_overlap);
5994                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5995         }
5996 ret:
5997         return retn;
5998 }
5999
6000 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6001                                           int *skipped)
6002 {
6003         struct r5conf *conf = mddev->private;
6004         struct stripe_head *sh;
6005         sector_t max_sector = mddev->dev_sectors;
6006         sector_t sync_blocks;
6007         int still_degraded = 0;
6008         int i;
6009
6010         if (sector_nr >= max_sector) {
6011                 /* just being told to finish up .. nothing much to do */
6012
6013                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6014                         end_reshape(conf);
6015                         return 0;
6016                 }
6017
6018                 if (mddev->curr_resync < max_sector) /* aborted */
6019                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6020                                         &sync_blocks, 1);
6021                 else /* completed sync */
6022                         conf->fullsync = 0;
6023                 bitmap_close_sync(mddev->bitmap);
6024
6025                 return 0;
6026         }
6027
6028         /* Allow raid5_quiesce to complete */
6029         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6030
6031         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6032                 return reshape_request(mddev, sector_nr, skipped);
6033
6034         /* No need to check resync_max as we never do more than one
6035          * stripe, and as resync_max will always be on a chunk boundary,
6036          * if the check in md_do_sync didn't fire, there is no chance
6037          * of overstepping resync_max here
6038          */
6039
6040         /* if there is too many failed drives and we are trying
6041          * to resync, then assert that we are finished, because there is
6042          * nothing we can do.
6043          */
6044         if (mddev->degraded >= conf->max_degraded &&
6045             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6046                 sector_t rv = mddev->dev_sectors - sector_nr;
6047                 *skipped = 1;
6048                 return rv;
6049         }
6050         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6051             !conf->fullsync &&
6052             !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6053             sync_blocks >= STRIPE_SECTORS) {
6054                 /* we can skip this block, and probably more */
6055                 sync_blocks /= STRIPE_SECTORS;
6056                 *skipped = 1;
6057                 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
6058         }
6059
6060         bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6061
6062         sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6063         if (sh == NULL) {
6064                 sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6065                 /* make sure we don't swamp the stripe cache if someone else
6066                  * is trying to get access
6067                  */
6068                 schedule_timeout_uninterruptible(1);
6069         }
6070         /* Need to check if array will still be degraded after recovery/resync
6071          * Note in case of > 1 drive failures it's possible we're rebuilding
6072          * one drive while leaving another faulty drive in array.
6073          */
6074         rcu_read_lock();
6075         for (i = 0; i < conf->raid_disks; i++) {
6076                 struct md_rdev *rdev = ACCESS_ONCE(conf->disks[i].rdev);
6077
6078                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6079                         still_degraded = 1;
6080         }
6081         rcu_read_unlock();
6082
6083         bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6084
6085         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6086         set_bit(STRIPE_HANDLE, &sh->state);
6087
6088         raid5_release_stripe(sh);
6089
6090         return STRIPE_SECTORS;
6091 }
6092
6093 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6094                                unsigned int offset)
6095 {
6096         /* We may not be able to submit a whole bio at once as there
6097          * may not be enough stripe_heads available.
6098          * We cannot pre-allocate enough stripe_heads as we may need
6099          * more than exist in the cache (if we allow ever large chunks).
6100          * So we do one stripe head at a time and record in
6101          * ->bi_hw_segments how many have been done.
6102          *
6103          * We *know* that this entire raid_bio is in one chunk, so
6104          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6105          */
6106         struct stripe_head *sh;
6107         int dd_idx;
6108         sector_t sector, logical_sector, last_sector;
6109         int scnt = 0;
6110         int handled = 0;
6111
6112         logical_sector = raid_bio->bi_iter.bi_sector &
6113                 ~((sector_t)STRIPE_SECTORS-1);
6114         sector = raid5_compute_sector(conf, logical_sector,
6115                                       0, &dd_idx, NULL);
6116         last_sector = bio_end_sector(raid_bio);
6117
6118         for (; logical_sector < last_sector;
6119              logical_sector += STRIPE_SECTORS,
6120                      sector += STRIPE_SECTORS,
6121                      scnt++) {
6122
6123                 if (scnt < offset)
6124                         /* already done this stripe */
6125                         continue;
6126
6127                 sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6128
6129                 if (!sh) {
6130                         /* failed to get a stripe - must wait */
6131                         conf->retry_read_aligned = raid_bio;
6132                         conf->retry_read_offset = scnt;
6133                         return handled;
6134                 }
6135
6136                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6137                         raid5_release_stripe(sh);
6138                         conf->retry_read_aligned = raid_bio;
6139                         conf->retry_read_offset = scnt;
6140                         return handled;
6141                 }
6142
6143                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6144                 handle_stripe(sh);
6145                 raid5_release_stripe(sh);
6146                 handled++;
6147         }
6148
6149         bio_endio(raid_bio);
6150
6151         if (atomic_dec_and_test(&conf->active_aligned_reads))
6152                 wake_up(&conf->wait_for_quiescent);
6153         return handled;
6154 }
6155
6156 static int handle_active_stripes(struct r5conf *conf, int group,
6157                                  struct r5worker *worker,
6158                                  struct list_head *temp_inactive_list)
6159 {
6160         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6161         int i, batch_size = 0, hash;
6162         bool release_inactive = false;
6163
6164         while (batch_size < MAX_STRIPE_BATCH &&
6165                         (sh = __get_priority_stripe(conf, group)) != NULL)
6166                 batch[batch_size++] = sh;
6167
6168         if (batch_size == 0) {
6169                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6170                         if (!list_empty(temp_inactive_list + i))
6171                                 break;
6172                 if (i == NR_STRIPE_HASH_LOCKS) {
6173                         spin_unlock_irq(&conf->device_lock);
6174                         r5l_flush_stripe_to_raid(conf->log);
6175                         spin_lock_irq(&conf->device_lock);
6176                         return batch_size;
6177                 }
6178                 release_inactive = true;
6179         }
6180         spin_unlock_irq(&conf->device_lock);
6181
6182         release_inactive_stripe_list(conf, temp_inactive_list,
6183                                      NR_STRIPE_HASH_LOCKS);
6184
6185         r5l_flush_stripe_to_raid(conf->log);
6186         if (release_inactive) {
6187                 spin_lock_irq(&conf->device_lock);
6188                 return 0;
6189         }
6190
6191         for (i = 0; i < batch_size; i++)
6192                 handle_stripe(batch[i]);
6193         log_write_stripe_run(conf);
6194
6195         cond_resched();
6196
6197         spin_lock_irq(&conf->device_lock);
6198         for (i = 0; i < batch_size; i++) {
6199                 hash = batch[i]->hash_lock_index;
6200                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6201         }
6202         return batch_size;
6203 }
6204
6205 static void raid5_do_work(struct work_struct *work)
6206 {
6207         struct r5worker *worker = container_of(work, struct r5worker, work);
6208         struct r5worker_group *group = worker->group;
6209         struct r5conf *conf = group->conf;
6210         struct mddev *mddev = conf->mddev;
6211         int group_id = group - conf->worker_groups;
6212         int handled;
6213         struct blk_plug plug;
6214
6215         pr_debug("+++ raid5worker active\n");
6216
6217         blk_start_plug(&plug);
6218         handled = 0;
6219         spin_lock_irq(&conf->device_lock);
6220         while (1) {
6221                 int batch_size, released;
6222
6223                 released = release_stripe_list(conf, worker->temp_inactive_list);
6224
6225                 batch_size = handle_active_stripes(conf, group_id, worker,
6226                                                    worker->temp_inactive_list);
6227                 worker->working = false;
6228                 if (!batch_size && !released)
6229                         break;
6230                 handled += batch_size;
6231                 wait_event_lock_irq(mddev->sb_wait,
6232                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6233                         conf->device_lock);
6234         }
6235         pr_debug("%d stripes handled\n", handled);
6236
6237         spin_unlock_irq(&conf->device_lock);
6238
6239         flush_deferred_bios(conf);
6240
6241         r5l_flush_stripe_to_raid(conf->log);
6242
6243         async_tx_issue_pending_all();
6244         blk_finish_plug(&plug);
6245
6246         pr_debug("--- raid5worker inactive\n");
6247 }
6248
6249 /*
6250  * This is our raid5 kernel thread.
6251  *
6252  * We scan the hash table for stripes which can be handled now.
6253  * During the scan, completed stripes are saved for us by the interrupt
6254  * handler, so that they will not have to wait for our next wakeup.
6255  */
6256 static void raid5d(struct md_thread *thread)
6257 {
6258         struct mddev *mddev = thread->mddev;
6259         struct r5conf *conf = mddev->private;
6260         int handled;
6261         struct blk_plug plug;
6262
6263         pr_debug("+++ raid5d active\n");
6264
6265         md_check_recovery(mddev);
6266
6267         blk_start_plug(&plug);
6268         handled = 0;
6269         spin_lock_irq(&conf->device_lock);
6270         while (1) {
6271                 struct bio *bio;
6272                 int batch_size, released;
6273                 unsigned int offset;
6274
6275                 released = release_stripe_list(conf, conf->temp_inactive_list);
6276                 if (released)
6277                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6278
6279                 if (
6280                     !list_empty(&conf->bitmap_list)) {
6281                         /* Now is a good time to flush some bitmap updates */
6282                         conf->seq_flush++;
6283                         spin_unlock_irq(&conf->device_lock);
6284                         bitmap_unplug(mddev->bitmap);
6285                         spin_lock_irq(&conf->device_lock);
6286                         conf->seq_write = conf->seq_flush;
6287                         activate_bit_delay(conf, conf->temp_inactive_list);
6288                 }
6289                 raid5_activate_delayed(conf);
6290
6291                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6292                         int ok;
6293                         spin_unlock_irq(&conf->device_lock);
6294                         ok = retry_aligned_read(conf, bio, offset);
6295                         spin_lock_irq(&conf->device_lock);
6296                         if (!ok)
6297                                 break;
6298                         handled++;
6299                 }
6300
6301                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6302                                                    conf->temp_inactive_list);
6303                 if (!batch_size && !released)
6304                         break;
6305                 handled += batch_size;
6306
6307                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6308                         spin_unlock_irq(&conf->device_lock);
6309                         md_check_recovery(mddev);
6310                         spin_lock_irq(&conf->device_lock);
6311                 }
6312         }
6313         pr_debug("%d stripes handled\n", handled);
6314
6315         spin_unlock_irq(&conf->device_lock);
6316         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6317             mutex_trylock(&conf->cache_size_mutex)) {
6318                 grow_one_stripe(conf, __GFP_NOWARN);
6319                 /* Set flag even if allocation failed.  This helps
6320                  * slow down allocation requests when mem is short
6321                  */
6322                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6323                 mutex_unlock(&conf->cache_size_mutex);
6324         }
6325
6326         flush_deferred_bios(conf);
6327
6328         r5l_flush_stripe_to_raid(conf->log);
6329
6330         async_tx_issue_pending_all();
6331         blk_finish_plug(&plug);
6332
6333         pr_debug("--- raid5d inactive\n");
6334 }
6335
6336 static ssize_t
6337 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6338 {
6339         struct r5conf *conf;
6340         int ret = 0;
6341         spin_lock(&mddev->lock);
6342         conf = mddev->private;
6343         if (conf)
6344                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6345         spin_unlock(&mddev->lock);
6346         return ret;
6347 }
6348
6349 int
6350 raid5_set_cache_size(struct mddev *mddev, int size)
6351 {
6352         int result = 0;
6353         struct r5conf *conf = mddev->private;
6354
6355         if (size <= 16 || size > 32768)
6356                 return -EINVAL;
6357
6358         conf->min_nr_stripes = size;
6359         mutex_lock(&conf->cache_size_mutex);
6360         while (size < conf->max_nr_stripes &&
6361                drop_one_stripe(conf))
6362                 ;
6363         mutex_unlock(&conf->cache_size_mutex);
6364
6365         md_allow_write(mddev);
6366
6367         mutex_lock(&conf->cache_size_mutex);
6368         while (size > conf->max_nr_stripes)
6369                 if (!grow_one_stripe(conf, GFP_KERNEL)) {
6370                         conf->min_nr_stripes = conf->max_nr_stripes;
6371                         result = -ENOMEM;
6372                         break;
6373                 }
6374         mutex_unlock(&conf->cache_size_mutex);
6375
6376         return result;
6377 }
6378 EXPORT_SYMBOL(raid5_set_cache_size);
6379
6380 static ssize_t
6381 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6382 {
6383         struct r5conf *conf;
6384         unsigned long new;
6385         int err;
6386
6387         if (len >= PAGE_SIZE)
6388                 return -EINVAL;
6389         if (kstrtoul(page, 10, &new))
6390                 return -EINVAL;
6391         err = mddev_lock(mddev);
6392         if (err)
6393                 return err;
6394         conf = mddev->private;
6395         if (!conf)
6396                 err = -ENODEV;
6397         else
6398                 err = raid5_set_cache_size(mddev, new);
6399         mddev_unlock(mddev);
6400
6401         return err ?: len;
6402 }
6403
6404 static struct md_sysfs_entry
6405 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6406                                 raid5_show_stripe_cache_size,
6407                                 raid5_store_stripe_cache_size);
6408
6409 static ssize_t
6410 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6411 {
6412         struct r5conf *conf = mddev->private;
6413         if (conf)
6414                 return sprintf(page, "%d\n", conf->rmw_level);
6415         else
6416                 return 0;
6417 }
6418
6419 static ssize_t
6420 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6421 {
6422         struct r5conf *conf = mddev->private;
6423         unsigned long new;
6424
6425         if (!conf)
6426                 return -ENODEV;
6427
6428         if (len >= PAGE_SIZE)
6429                 return -EINVAL;
6430
6431         if (kstrtoul(page, 10, &new))
6432                 return -EINVAL;
6433
6434         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6435                 return -EINVAL;
6436
6437         if (new != PARITY_DISABLE_RMW &&
6438             new != PARITY_ENABLE_RMW &&
6439             new != PARITY_PREFER_RMW)
6440                 return -EINVAL;
6441
6442         conf->rmw_level = new;
6443         return len;
6444 }
6445
6446 static struct md_sysfs_entry
6447 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6448                          raid5_show_rmw_level,
6449                          raid5_store_rmw_level);
6450
6451
6452 static ssize_t
6453 raid5_show_preread_threshold(struct mddev *mddev, char *page)
6454 {
6455         struct r5conf *conf;
6456         int ret = 0;
6457         spin_lock(&mddev->lock);
6458         conf = mddev->private;
6459         if (conf)
6460                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
6461         spin_unlock(&mddev->lock);
6462         return ret;
6463 }
6464
6465 static ssize_t
6466 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
6467 {
6468         struct r5conf *conf;
6469         unsigned long new;
6470         int err;
6471
6472         if (len >= PAGE_SIZE)
6473                 return -EINVAL;
6474         if (kstrtoul(page, 10, &new))
6475                 return -EINVAL;
6476
6477         err = mddev_lock(mddev);
6478         if (err)
6479                 return err;
6480         conf = mddev->private;
6481         if (!conf)
6482                 err = -ENODEV;
6483         else if (new > conf->min_nr_stripes)
6484                 err = -EINVAL;
6485         else
6486                 conf->bypass_threshold = new;
6487         mddev_unlock(mddev);
6488         return err ?: len;
6489 }
6490
6491 static struct md_sysfs_entry
6492 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
6493                                         S_IRUGO | S_IWUSR,
6494                                         raid5_show_preread_threshold,
6495                                         raid5_store_preread_threshold);
6496
6497 static ssize_t
6498 raid5_show_skip_copy(struct mddev *mddev, char *page)
6499 {
6500         struct r5conf *conf;
6501         int ret = 0;
6502         spin_lock(&mddev->lock);
6503         conf = mddev->private;
6504         if (conf)
6505                 ret = sprintf(page, "%d\n", conf->skip_copy);
6506         spin_unlock(&mddev->lock);
6507         return ret;
6508 }
6509
6510 static ssize_t
6511 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
6512 {
6513         struct r5conf *conf;
6514         unsigned long new;
6515         int err;
6516
6517         if (len >= PAGE_SIZE)
6518                 return -EINVAL;
6519         if (kstrtoul(page, 10, &new))
6520                 return -EINVAL;
6521         new = !!new;
6522
6523         err = mddev_lock(mddev);
6524         if (err)
6525                 return err;
6526         conf = mddev->private;
6527         if (!conf)
6528                 err = -ENODEV;
6529         else if (new != conf->skip_copy) {
6530                 mddev_suspend(mddev);
6531                 conf->skip_copy = new;
6532                 if (new)
6533                         mddev->queue->backing_dev_info->capabilities |=
6534                                 BDI_CAP_STABLE_WRITES;
6535                 else
6536                         mddev->queue->backing_dev_info->capabilities &=
6537                                 ~BDI_CAP_STABLE_WRITES;
6538                 mddev_resume(mddev);
6539         }
6540         mddev_unlock(mddev);
6541         return err ?: len;
6542 }
6543
6544 static struct md_sysfs_entry
6545 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
6546                                         raid5_show_skip_copy,
6547                                         raid5_store_skip_copy);
6548
6549 static ssize_t
6550 stripe_cache_active_show(struct mddev *mddev, char *page)
6551 {
6552         struct r5conf *conf = mddev->private;
6553         if (conf)
6554                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
6555         else
6556                 return 0;
6557 }
6558
6559 static struct md_sysfs_entry
6560 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
6561
6562 static ssize_t
6563 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
6564 {
6565         struct r5conf *conf;
6566         int ret = 0;
6567         spin_lock(&mddev->lock);
6568         conf = mddev->private;
6569         if (conf)
6570                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
6571         spin_unlock(&mddev->lock);
6572         return ret;
6573 }
6574
6575 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6576                                int *group_cnt,
6577                                int *worker_cnt_per_group,
6578                                struct r5worker_group **worker_groups);
6579 static ssize_t
6580 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
6581 {
6582         struct r5conf *conf;
6583         unsigned int new;
6584         int err;
6585         struct r5worker_group *new_groups, *old_groups;
6586         int group_cnt, worker_cnt_per_group;
6587
6588         if (len >= PAGE_SIZE)
6589                 return -EINVAL;
6590         if (kstrtouint(page, 10, &new))
6591                 return -EINVAL;
6592         /* 8192 should be big enough */
6593         if (new > 8192)
6594                 return -EINVAL;
6595
6596         err = mddev_lock(mddev);
6597         if (err)
6598                 return err;
6599         conf = mddev->private;
6600         if (!conf)
6601                 err = -ENODEV;
6602         else if (new != conf->worker_cnt_per_group) {
6603                 mddev_suspend(mddev);
6604
6605                 old_groups = conf->worker_groups;
6606                 if (old_groups)
6607                         flush_workqueue(raid5_wq);
6608
6609                 err = alloc_thread_groups(conf, new,
6610                                           &group_cnt, &worker_cnt_per_group,
6611                                           &new_groups);
6612                 if (!err) {
6613                         spin_lock_irq(&conf->device_lock);
6614                         conf->group_cnt = group_cnt;
6615                         conf->worker_cnt_per_group = worker_cnt_per_group;
6616                         conf->worker_groups = new_groups;
6617                         spin_unlock_irq(&conf->device_lock);
6618
6619                         if (old_groups)
6620                                 kfree(old_groups[0].workers);
6621                         kfree(old_groups);
6622                 }
6623                 mddev_resume(mddev);
6624         }
6625         mddev_unlock(mddev);
6626
6627         return err ?: len;
6628 }
6629
6630 static struct md_sysfs_entry
6631 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
6632                                 raid5_show_group_thread_cnt,
6633                                 raid5_store_group_thread_cnt);
6634
6635 static struct attribute *raid5_attrs[] =  {
6636         &raid5_stripecache_size.attr,
6637         &raid5_stripecache_active.attr,
6638         &raid5_preread_bypass_threshold.attr,
6639         &raid5_group_thread_cnt.attr,
6640         &raid5_skip_copy.attr,
6641         &raid5_rmw_level.attr,
6642         &r5c_journal_mode.attr,
6643         NULL,
6644 };
6645 static struct attribute_group raid5_attrs_group = {
6646         .name = NULL,
6647         .attrs = raid5_attrs,
6648 };
6649
6650 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6651                                int *group_cnt,
6652                                int *worker_cnt_per_group,
6653                                struct r5worker_group **worker_groups)
6654 {
6655         int i, j, k;
6656         ssize_t size;
6657         struct r5worker *workers;
6658
6659         *worker_cnt_per_group = cnt;
6660         if (cnt == 0) {
6661                 *group_cnt = 0;
6662                 *worker_groups = NULL;
6663                 return 0;
6664         }
6665         *group_cnt = num_possible_nodes();
6666         size = sizeof(struct r5worker) * cnt;
6667         workers = kzalloc(size * *group_cnt, GFP_NOIO);
6668         *worker_groups = kzalloc(sizeof(struct r5worker_group) *
6669                                 *group_cnt, GFP_NOIO);
6670         if (!*worker_groups || !workers) {
6671                 kfree(workers);
6672                 kfree(*worker_groups);
6673                 return -ENOMEM;
6674         }
6675
6676         for (i = 0; i < *group_cnt; i++) {
6677                 struct r5worker_group *group;
6678
6679                 group = &(*worker_groups)[i];
6680                 INIT_LIST_HEAD(&group->handle_list);
6681                 INIT_LIST_HEAD(&group->loprio_list);
6682                 group->conf = conf;
6683                 group->workers = workers + i * cnt;
6684
6685                 for (j = 0; j < cnt; j++) {
6686                         struct r5worker *worker = group->workers + j;
6687                         worker->group = group;
6688                         INIT_WORK(&worker->work, raid5_do_work);
6689
6690                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
6691                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
6692                 }
6693         }
6694
6695         return 0;
6696 }
6697
6698 static void free_thread_groups(struct r5conf *conf)
6699 {
6700         if (conf->worker_groups)
6701                 kfree(conf->worker_groups[0].workers);
6702         kfree(conf->worker_groups);
6703         conf->worker_groups = NULL;
6704 }
6705
6706 static sector_t
6707 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
6708 {
6709         struct r5conf *conf = mddev->private;
6710
6711         if (!sectors)
6712                 sectors = mddev->dev_sectors;
6713         if (!raid_disks)
6714                 /* size is defined by the smallest of previous and new size */
6715                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
6716
6717         sectors &= ~((sector_t)conf->chunk_sectors - 1);
6718         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
6719         return sectors * (raid_disks - conf->max_degraded);
6720 }
6721
6722 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6723 {
6724         safe_put_page(percpu->spare_page);
6725         if (percpu->scribble)
6726                 flex_array_free(percpu->scribble);
6727         percpu->spare_page = NULL;
6728         percpu->scribble = NULL;
6729 }
6730
6731 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6732 {
6733         if (conf->level == 6 && !percpu->spare_page)
6734                 percpu->spare_page = alloc_page(GFP_KERNEL);
6735         if (!percpu->scribble)
6736                 percpu->scribble = scribble_alloc(max(conf->raid_disks,
6737                                                       conf->previous_raid_disks),
6738                                                   max(conf->chunk_sectors,
6739                                                       conf->prev_chunk_sectors)
6740                                                    / STRIPE_SECTORS,
6741                                                   GFP_KERNEL);
6742
6743         if (!percpu->scribble || (conf->level == 6 && !percpu->spare_page)) {
6744                 free_scratch_buffer(conf, percpu);
6745                 return -ENOMEM;
6746         }
6747
6748         return 0;
6749 }
6750
6751 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
6752 {
6753         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6754
6755         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
6756         return 0;
6757 }
6758
6759 static void raid5_free_percpu(struct r5conf *conf)
6760 {
6761         if (!conf->percpu)
6762                 return;
6763
6764         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6765         free_percpu(conf->percpu);
6766 }
6767
6768 static void free_conf(struct r5conf *conf)
6769 {
6770         int i;
6771
6772         log_exit(conf);
6773
6774         if (conf->shrinker.nr_deferred)
6775                 unregister_shrinker(&conf->shrinker);
6776
6777         free_thread_groups(conf);
6778         shrink_stripes(conf);
6779         raid5_free_percpu(conf);
6780         for (i = 0; i < conf->pool_size; i++)
6781                 if (conf->disks[i].extra_page)
6782                         put_page(conf->disks[i].extra_page);
6783         kfree(conf->disks);
6784         if (conf->bio_split)
6785                 bioset_free(conf->bio_split);
6786         kfree(conf->stripe_hashtbl);
6787         kfree(conf->pending_data);
6788         kfree(conf);
6789 }
6790
6791 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
6792 {
6793         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6794         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
6795
6796         if (alloc_scratch_buffer(conf, percpu)) {
6797                 pr_warn("%s: failed memory allocation for cpu%u\n",
6798                         __func__, cpu);
6799                 return -ENOMEM;
6800         }
6801         return 0;
6802 }
6803
6804 static int raid5_alloc_percpu(struct r5conf *conf)
6805 {
6806         int err = 0;
6807
6808         conf->percpu = alloc_percpu(struct raid5_percpu);
6809         if (!conf->percpu)
6810                 return -ENOMEM;
6811
6812         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6813         if (!err) {
6814                 conf->scribble_disks = max(conf->raid_disks,
6815                         conf->previous_raid_disks);
6816                 conf->scribble_sectors = max(conf->chunk_sectors,
6817                         conf->prev_chunk_sectors);
6818         }
6819         return err;
6820 }
6821
6822 static unsigned long raid5_cache_scan(struct shrinker *shrink,
6823                                       struct shrink_control *sc)
6824 {
6825         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6826         unsigned long ret = SHRINK_STOP;
6827
6828         if (mutex_trylock(&conf->cache_size_mutex)) {
6829                 ret= 0;
6830                 while (ret < sc->nr_to_scan &&
6831                        conf->max_nr_stripes > conf->min_nr_stripes) {
6832                         if (drop_one_stripe(conf) == 0) {
6833                                 ret = SHRINK_STOP;
6834                                 break;
6835                         }
6836                         ret++;
6837                 }
6838                 mutex_unlock(&conf->cache_size_mutex);
6839         }
6840         return ret;
6841 }
6842
6843 static unsigned long raid5_cache_count(struct shrinker *shrink,
6844                                        struct shrink_control *sc)
6845 {
6846         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6847
6848         if (conf->max_nr_stripes < conf->min_nr_stripes)
6849                 /* unlikely, but not impossible */
6850                 return 0;
6851         return conf->max_nr_stripes - conf->min_nr_stripes;
6852 }
6853
6854 static struct r5conf *setup_conf(struct mddev *mddev)
6855 {
6856         struct r5conf *conf;
6857         int raid_disk, memory, max_disks;
6858         struct md_rdev *rdev;
6859         struct disk_info *disk;
6860         char pers_name[6];
6861         int i;
6862         int group_cnt, worker_cnt_per_group;
6863         struct r5worker_group *new_group;
6864
6865         if (mddev->new_level != 5
6866             && mddev->new_level != 4
6867             && mddev->new_level != 6) {
6868                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
6869                         mdname(mddev), mddev->new_level);
6870                 return ERR_PTR(-EIO);
6871         }
6872         if ((mddev->new_level == 5
6873              && !algorithm_valid_raid5(mddev->new_layout)) ||
6874             (mddev->new_level == 6
6875              && !algorithm_valid_raid6(mddev->new_layout))) {
6876                 pr_warn("md/raid:%s: layout %d not supported\n",
6877                         mdname(mddev), mddev->new_layout);
6878                 return ERR_PTR(-EIO);
6879         }
6880         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
6881                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
6882                         mdname(mddev), mddev->raid_disks);
6883                 return ERR_PTR(-EINVAL);
6884         }
6885
6886         if (!mddev->new_chunk_sectors ||
6887             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
6888             !is_power_of_2(mddev->new_chunk_sectors)) {
6889                 pr_warn("md/raid:%s: invalid chunk size %d\n",
6890                         mdname(mddev), mddev->new_chunk_sectors << 9);
6891                 return ERR_PTR(-EINVAL);
6892         }
6893
6894         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
6895         if (conf == NULL)
6896                 goto abort;
6897         INIT_LIST_HEAD(&conf->free_list);
6898         INIT_LIST_HEAD(&conf->pending_list);
6899         conf->pending_data = kzalloc(sizeof(struct r5pending_data) *
6900                 PENDING_IO_MAX, GFP_KERNEL);
6901         if (!conf->pending_data)
6902                 goto abort;
6903         for (i = 0; i < PENDING_IO_MAX; i++)
6904                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
6905         /* Don't enable multi-threading by default*/
6906         if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group,
6907                                  &new_group)) {
6908                 conf->group_cnt = group_cnt;
6909                 conf->worker_cnt_per_group = worker_cnt_per_group;
6910                 conf->worker_groups = new_group;
6911         } else
6912                 goto abort;
6913         spin_lock_init(&conf->device_lock);
6914         seqcount_init(&conf->gen_lock);
6915         mutex_init(&conf->cache_size_mutex);
6916         init_waitqueue_head(&conf->wait_for_quiescent);
6917         init_waitqueue_head(&conf->wait_for_stripe);
6918         init_waitqueue_head(&conf->wait_for_overlap);
6919         INIT_LIST_HEAD(&conf->handle_list);
6920         INIT_LIST_HEAD(&conf->loprio_list);
6921         INIT_LIST_HEAD(&conf->hold_list);
6922         INIT_LIST_HEAD(&conf->delayed_list);
6923         INIT_LIST_HEAD(&conf->bitmap_list);
6924         init_llist_head(&conf->released_stripes);
6925         atomic_set(&conf->active_stripes, 0);
6926         atomic_set(&conf->preread_active_stripes, 0);
6927         atomic_set(&conf->active_aligned_reads, 0);
6928         spin_lock_init(&conf->pending_bios_lock);
6929         conf->batch_bio_dispatch = true;
6930         rdev_for_each(rdev, mddev) {
6931                 if (test_bit(Journal, &rdev->flags))
6932                         continue;
6933                 if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
6934                         conf->batch_bio_dispatch = false;
6935                         break;
6936                 }
6937         }
6938
6939         conf->bypass_threshold = BYPASS_THRESHOLD;
6940         conf->recovery_disabled = mddev->recovery_disabled - 1;
6941
6942         conf->raid_disks = mddev->raid_disks;
6943         if (mddev->reshape_position == MaxSector)
6944                 conf->previous_raid_disks = mddev->raid_disks;
6945         else
6946                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
6947         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
6948
6949         conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
6950                               GFP_KERNEL);
6951
6952         if (!conf->disks)
6953                 goto abort;
6954
6955         for (i = 0; i < max_disks; i++) {
6956                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
6957                 if (!conf->disks[i].extra_page)
6958                         goto abort;
6959         }
6960
6961         conf->bio_split = bioset_create(BIO_POOL_SIZE, 0, 0);
6962         if (!conf->bio_split)
6963                 goto abort;
6964         conf->mddev = mddev;
6965
6966         if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
6967                 goto abort;
6968
6969         /* We init hash_locks[0] separately to that it can be used
6970          * as the reference lock in the spin_lock_nest_lock() call
6971          * in lock_all_device_hash_locks_irq in order to convince
6972          * lockdep that we know what we are doing.
6973          */
6974         spin_lock_init(conf->hash_locks);
6975         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
6976                 spin_lock_init(conf->hash_locks + i);
6977
6978         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6979                 INIT_LIST_HEAD(conf->inactive_list + i);
6980
6981         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6982                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
6983
6984         atomic_set(&conf->r5c_cached_full_stripes, 0);
6985         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
6986         atomic_set(&conf->r5c_cached_partial_stripes, 0);
6987         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
6988         atomic_set(&conf->r5c_flushing_full_stripes, 0);
6989         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
6990
6991         conf->level = mddev->new_level;
6992         conf->chunk_sectors = mddev->new_chunk_sectors;
6993         if (raid5_alloc_percpu(conf) != 0)
6994                 goto abort;
6995
6996         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
6997
6998         rdev_for_each(rdev, mddev) {
6999                 raid_disk = rdev->raid_disk;
7000                 if (raid_disk >= max_disks
7001                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7002                         continue;
7003                 disk = conf->disks + raid_disk;
7004
7005                 if (test_bit(Replacement, &rdev->flags)) {
7006                         if (disk->replacement)
7007                                 goto abort;
7008                         disk->replacement = rdev;
7009                 } else {
7010                         if (disk->rdev)
7011                                 goto abort;
7012                         disk->rdev = rdev;
7013                 }
7014
7015                 if (test_bit(In_sync, &rdev->flags)) {
7016                         char b[BDEVNAME_SIZE];
7017                         pr_info("md/raid:%s: device %s operational as raid disk %d\n",
7018                                 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
7019                 } else if (rdev->saved_raid_disk != raid_disk)
7020                         /* Cannot rely on bitmap to complete recovery */
7021                         conf->fullsync = 1;
7022         }
7023
7024         conf->level = mddev->new_level;
7025         if (conf->level == 6) {
7026                 conf->max_degraded = 2;
7027                 if (raid6_call.xor_syndrome)
7028                         conf->rmw_level = PARITY_ENABLE_RMW;
7029                 else
7030                         conf->rmw_level = PARITY_DISABLE_RMW;
7031         } else {
7032                 conf->max_degraded = 1;
7033                 conf->rmw_level = PARITY_ENABLE_RMW;
7034         }
7035         conf->algorithm = mddev->new_layout;
7036         conf->reshape_progress = mddev->reshape_position;
7037         if (conf->reshape_progress != MaxSector) {
7038                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7039                 conf->prev_algo = mddev->layout;
7040         } else {
7041                 conf->prev_chunk_sectors = conf->chunk_sectors;
7042                 conf->prev_algo = conf->algorithm;
7043         }
7044
7045         conf->min_nr_stripes = NR_STRIPES;
7046         if (mddev->reshape_position != MaxSector) {
7047                 int stripes = max_t(int,
7048                         ((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4,
7049                         ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4);
7050                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7051                 if (conf->min_nr_stripes != NR_STRIPES)
7052                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7053                                 mdname(mddev), conf->min_nr_stripes);
7054         }
7055         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7056                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7057         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7058         if (grow_stripes(conf, conf->min_nr_stripes)) {
7059                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7060                         mdname(mddev), memory);
7061                 goto abort;
7062         } else
7063                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7064         /*
7065          * Losing a stripe head costs more than the time to refill it,
7066          * it reduces the queue depth and so can hurt throughput.
7067          * So set it rather large, scaled by number of devices.
7068          */
7069         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7070         conf->shrinker.scan_objects = raid5_cache_scan;
7071         conf->shrinker.count_objects = raid5_cache_count;
7072         conf->shrinker.batch = 128;
7073         conf->shrinker.flags = 0;
7074         if (register_shrinker(&conf->shrinker)) {
7075                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7076                         mdname(mddev));
7077                 goto abort;
7078         }
7079
7080         sprintf(pers_name, "raid%d", mddev->new_level);
7081         conf->thread = md_register_thread(raid5d, mddev, pers_name);
7082         if (!conf->thread) {
7083                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7084                         mdname(mddev));
7085                 goto abort;
7086         }
7087
7088         return conf;
7089
7090  abort:
7091         if (conf) {
7092                 free_conf(conf);
7093                 return ERR_PTR(-EIO);
7094         } else
7095                 return ERR_PTR(-ENOMEM);
7096 }
7097
7098 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7099 {
7100         switch (algo) {
7101         case ALGORITHM_PARITY_0:
7102                 if (raid_disk < max_degraded)
7103                         return 1;
7104                 break;
7105         case ALGORITHM_PARITY_N:
7106                 if (raid_disk >= raid_disks - max_degraded)
7107                         return 1;
7108                 break;
7109         case ALGORITHM_PARITY_0_6:
7110                 if (raid_disk == 0 ||
7111                     raid_disk == raid_disks - 1)
7112                         return 1;
7113                 break;
7114         case ALGORITHM_LEFT_ASYMMETRIC_6:
7115         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7116         case ALGORITHM_LEFT_SYMMETRIC_6:
7117         case ALGORITHM_RIGHT_SYMMETRIC_6:
7118                 if (raid_disk == raid_disks - 1)
7119                         return 1;
7120         }
7121         return 0;
7122 }
7123
7124 static int raid5_run(struct mddev *mddev)
7125 {
7126         struct r5conf *conf;
7127         int working_disks = 0;
7128         int dirty_parity_disks = 0;
7129         struct md_rdev *rdev;
7130         struct md_rdev *journal_dev = NULL;
7131         sector_t reshape_offset = 0;
7132         int i;
7133         long long min_offset_diff = 0;
7134         int first = 1;
7135
7136         if (mddev_init_writes_pending(mddev) < 0)
7137                 return -ENOMEM;
7138
7139         if (mddev->recovery_cp != MaxSector)
7140                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7141                           mdname(mddev));
7142
7143         rdev_for_each(rdev, mddev) {
7144                 long long diff;
7145
7146                 if (test_bit(Journal, &rdev->flags)) {
7147                         journal_dev = rdev;
7148                         continue;
7149                 }
7150                 if (rdev->raid_disk < 0)
7151                         continue;
7152                 diff = (rdev->new_data_offset - rdev->data_offset);
7153                 if (first) {
7154                         min_offset_diff = diff;
7155                         first = 0;
7156                 } else if (mddev->reshape_backwards &&
7157                          diff < min_offset_diff)
7158                         min_offset_diff = diff;
7159                 else if (!mddev->reshape_backwards &&
7160                          diff > min_offset_diff)
7161                         min_offset_diff = diff;
7162         }
7163
7164         if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7165             (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7166                 pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7167                           mdname(mddev));
7168                 return -EINVAL;
7169         }
7170
7171         if (mddev->reshape_position != MaxSector) {
7172                 /* Check that we can continue the reshape.
7173                  * Difficulties arise if the stripe we would write to
7174                  * next is at or after the stripe we would read from next.
7175                  * For a reshape that changes the number of devices, this
7176                  * is only possible for a very short time, and mdadm makes
7177                  * sure that time appears to have past before assembling
7178                  * the array.  So we fail if that time hasn't passed.
7179                  * For a reshape that keeps the number of devices the same
7180                  * mdadm must be monitoring the reshape can keeping the
7181                  * critical areas read-only and backed up.  It will start
7182                  * the array in read-only mode, so we check for that.
7183                  */
7184                 sector_t here_new, here_old;
7185                 int old_disks;
7186                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7187                 int chunk_sectors;
7188                 int new_data_disks;
7189
7190                 if (journal_dev) {
7191                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7192                                 mdname(mddev));
7193                         return -EINVAL;
7194                 }
7195
7196                 if (mddev->new_level != mddev->level) {
7197                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7198                                 mdname(mddev));
7199                         return -EINVAL;
7200                 }
7201                 old_disks = mddev->raid_disks - mddev->delta_disks;
7202                 /* reshape_position must be on a new-stripe boundary, and one
7203                  * further up in new geometry must map after here in old
7204                  * geometry.
7205                  * If the chunk sizes are different, then as we perform reshape
7206                  * in units of the largest of the two, reshape_position needs
7207                  * be a multiple of the largest chunk size times new data disks.
7208                  */
7209                 here_new = mddev->reshape_position;
7210                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7211                 new_data_disks = mddev->raid_disks - max_degraded;
7212                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7213                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7214                                 mdname(mddev));
7215                         return -EINVAL;
7216                 }
7217                 reshape_offset = here_new * chunk_sectors;
7218                 /* here_new is the stripe we will write to */
7219                 here_old = mddev->reshape_position;
7220                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7221                 /* here_old is the first stripe that we might need to read
7222                  * from */
7223                 if (mddev->delta_disks == 0) {
7224                         /* We cannot be sure it is safe to start an in-place
7225                          * reshape.  It is only safe if user-space is monitoring
7226                          * and taking constant backups.
7227                          * mdadm always starts a situation like this in
7228                          * readonly mode so it can take control before
7229                          * allowing any writes.  So just check for that.
7230                          */
7231                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7232                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7233                                 /* not really in-place - so OK */;
7234                         else if (mddev->ro == 0) {
7235                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7236                                         mdname(mddev));
7237                                 return -EINVAL;
7238                         }
7239                 } else if (mddev->reshape_backwards
7240                     ? (here_new * chunk_sectors + min_offset_diff <=
7241                        here_old * chunk_sectors)
7242                     : (here_new * chunk_sectors >=
7243                        here_old * chunk_sectors + (-min_offset_diff))) {
7244                         /* Reading from the same stripe as writing to - bad */
7245                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7246                                 mdname(mddev));
7247                         return -EINVAL;
7248                 }
7249                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7250                 /* OK, we should be able to continue; */
7251         } else {
7252                 BUG_ON(mddev->level != mddev->new_level);
7253                 BUG_ON(mddev->layout != mddev->new_layout);
7254                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7255                 BUG_ON(mddev->delta_disks != 0);
7256         }
7257
7258         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7259             test_bit(MD_HAS_PPL, &mddev->flags)) {
7260                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7261                         mdname(mddev));
7262                 clear_bit(MD_HAS_PPL, &mddev->flags);
7263                 clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7264         }
7265
7266         if (mddev->private == NULL)
7267                 conf = setup_conf(mddev);
7268         else
7269                 conf = mddev->private;
7270
7271         if (IS_ERR(conf))
7272                 return PTR_ERR(conf);
7273
7274         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7275                 if (!journal_dev) {
7276                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7277                                 mdname(mddev));
7278                         mddev->ro = 1;
7279                         set_disk_ro(mddev->gendisk, 1);
7280                 } else if (mddev->recovery_cp == MaxSector)
7281                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7282         }
7283
7284         conf->min_offset_diff = min_offset_diff;
7285         mddev->thread = conf->thread;
7286         conf->thread = NULL;
7287         mddev->private = conf;
7288
7289         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7290              i++) {
7291                 rdev = conf->disks[i].rdev;
7292                 if (!rdev && conf->disks[i].replacement) {
7293                         /* The replacement is all we have yet */
7294                         rdev = conf->disks[i].replacement;
7295                         conf->disks[i].replacement = NULL;
7296                         clear_bit(Replacement, &rdev->flags);
7297                         conf->disks[i].rdev = rdev;
7298                 }
7299                 if (!rdev)
7300                         continue;
7301                 if (conf->disks[i].replacement &&
7302                     conf->reshape_progress != MaxSector) {
7303                         /* replacements and reshape simply do not mix. */
7304                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7305                         goto abort;
7306                 }
7307                 if (test_bit(In_sync, &rdev->flags)) {
7308                         working_disks++;
7309                         continue;
7310                 }
7311                 /* This disc is not fully in-sync.  However if it
7312                  * just stored parity (beyond the recovery_offset),
7313                  * when we don't need to be concerned about the
7314                  * array being dirty.
7315                  * When reshape goes 'backwards', we never have
7316                  * partially completed devices, so we only need
7317                  * to worry about reshape going forwards.
7318                  */
7319                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7320                 if (mddev->major_version == 0 &&
7321                     mddev->minor_version > 90)
7322                         rdev->recovery_offset = reshape_offset;
7323
7324                 if (rdev->recovery_offset < reshape_offset) {
7325                         /* We need to check old and new layout */
7326                         if (!only_parity(rdev->raid_disk,
7327                                          conf->algorithm,
7328                                          conf->raid_disks,
7329                                          conf->max_degraded))
7330                                 continue;
7331                 }
7332                 if (!only_parity(rdev->raid_disk,
7333                                  conf->prev_algo,
7334                                  conf->previous_raid_disks,
7335                                  conf->max_degraded))
7336                         continue;
7337                 dirty_parity_disks++;
7338         }
7339
7340         /*
7341          * 0 for a fully functional array, 1 or 2 for a degraded array.
7342          */
7343         mddev->degraded = raid5_calc_degraded(conf);
7344
7345         if (has_failed(conf)) {
7346                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7347                         mdname(mddev), mddev->degraded, conf->raid_disks);
7348                 goto abort;
7349         }
7350
7351         /* device size must be a multiple of chunk size */
7352         mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
7353         mddev->resync_max_sectors = mddev->dev_sectors;
7354
7355         if (mddev->degraded > dirty_parity_disks &&
7356             mddev->recovery_cp != MaxSector) {
7357                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7358                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7359                                 mdname(mddev));
7360                 else if (mddev->ok_start_degraded)
7361                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7362                                 mdname(mddev));
7363                 else {
7364                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7365                                 mdname(mddev));
7366                         goto abort;
7367                 }
7368         }
7369
7370         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7371                 mdname(mddev), conf->level,
7372                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7373                 mddev->new_layout);
7374
7375         print_raid5_conf(conf);
7376
7377         if (conf->reshape_progress != MaxSector) {
7378                 conf->reshape_safe = conf->reshape_progress;
7379                 atomic_set(&conf->reshape_stripes, 0);
7380                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7381                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7382                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7383                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7384                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7385                                                         "reshape");
7386                 if (!mddev->sync_thread)
7387                         goto abort;
7388         }
7389
7390         /* Ok, everything is just fine now */
7391         if (mddev->to_remove == &raid5_attrs_group)
7392                 mddev->to_remove = NULL;
7393         else if (mddev->kobj.sd &&
7394             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7395                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
7396                         mdname(mddev));
7397         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7398
7399         if (mddev->queue) {
7400                 int chunk_size;
7401                 /* read-ahead size must cover two whole stripes, which
7402                  * is 2 * (datadisks) * chunksize where 'n' is the
7403                  * number of raid devices
7404                  */
7405                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
7406                 int stripe = data_disks *
7407                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
7408                 if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7409                         mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7410
7411                 chunk_size = mddev->chunk_sectors << 9;
7412                 blk_queue_io_min(mddev->queue, chunk_size);
7413                 blk_queue_io_opt(mddev->queue, chunk_size *
7414                                  (conf->raid_disks - conf->max_degraded));
7415                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
7416                 /*
7417                  * We can only discard a whole stripe. It doesn't make sense to
7418                  * discard data disk but write parity disk
7419                  */
7420                 stripe = stripe * PAGE_SIZE;
7421                 /* Round up to power of 2, as discard handling
7422                  * currently assumes that */
7423                 while ((stripe-1) & stripe)
7424                         stripe = (stripe | (stripe-1)) + 1;
7425                 mddev->queue->limits.discard_alignment = stripe;
7426                 mddev->queue->limits.discard_granularity = stripe;
7427
7428                 blk_queue_max_write_same_sectors(mddev->queue, 0);
7429                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
7430
7431                 rdev_for_each(rdev, mddev) {
7432                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7433                                           rdev->data_offset << 9);
7434                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7435                                           rdev->new_data_offset << 9);
7436                 }
7437
7438                 /*
7439                  * zeroing is required, otherwise data
7440                  * could be lost. Consider a scenario: discard a stripe
7441                  * (the stripe could be inconsistent if
7442                  * discard_zeroes_data is 0); write one disk of the
7443                  * stripe (the stripe could be inconsistent again
7444                  * depending on which disks are used to calculate
7445                  * parity); the disk is broken; The stripe data of this
7446                  * disk is lost.
7447                  *
7448                  * We only allow DISCARD if the sysadmin has confirmed that
7449                  * only safe devices are in use by setting a module parameter.
7450                  * A better idea might be to turn DISCARD into WRITE_ZEROES
7451                  * requests, as that is required to be safe.
7452                  */
7453                 if (devices_handle_discard_safely &&
7454                     mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
7455                     mddev->queue->limits.discard_granularity >= stripe)
7456                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
7457                                                 mddev->queue);
7458                 else
7459                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
7460                                                 mddev->queue);
7461
7462                 blk_queue_max_hw_sectors(mddev->queue, UINT_MAX);
7463         }
7464
7465         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
7466                 goto abort;
7467
7468         return 0;
7469 abort:
7470         md_unregister_thread(&mddev->thread);
7471         print_raid5_conf(conf);
7472         free_conf(conf);
7473         mddev->private = NULL;
7474         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
7475         return -EIO;
7476 }
7477
7478 static void raid5_free(struct mddev *mddev, void *priv)
7479 {
7480         struct r5conf *conf = priv;
7481
7482         free_conf(conf);
7483         mddev->to_remove = &raid5_attrs_group;
7484 }
7485
7486 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
7487 {
7488         struct r5conf *conf = mddev->private;
7489         int i;
7490
7491         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
7492                 conf->chunk_sectors / 2, mddev->layout);
7493         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
7494         rcu_read_lock();
7495         for (i = 0; i < conf->raid_disks; i++) {
7496                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
7497                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
7498         }
7499         rcu_read_unlock();
7500         seq_printf (seq, "]");
7501 }
7502
7503 static void print_raid5_conf (struct r5conf *conf)
7504 {
7505         int i;
7506         struct disk_info *tmp;
7507
7508         pr_debug("RAID conf printout:\n");
7509         if (!conf) {
7510                 pr_debug("(conf==NULL)\n");
7511                 return;
7512         }
7513         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
7514                conf->raid_disks,
7515                conf->raid_disks - conf->mddev->degraded);
7516
7517         for (i = 0; i < conf->raid_disks; i++) {
7518                 char b[BDEVNAME_SIZE];
7519                 tmp = conf->disks + i;
7520                 if (tmp->rdev)
7521                         pr_debug(" disk %d, o:%d, dev:%s\n",
7522                                i, !test_bit(Faulty, &tmp->rdev->flags),
7523                                bdevname(tmp->rdev->bdev, b));
7524         }
7525 }
7526
7527 static int raid5_spare_active(struct mddev *mddev)
7528 {
7529         int i;
7530         struct r5conf *conf = mddev->private;
7531         struct disk_info *tmp;
7532         int count = 0;
7533         unsigned long flags;
7534
7535         for (i = 0; i < conf->raid_disks; i++) {
7536                 tmp = conf->disks + i;
7537                 if (tmp->replacement
7538                     && tmp->replacement->recovery_offset == MaxSector
7539                     && !test_bit(Faulty, &tmp->replacement->flags)
7540                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
7541                         /* Replacement has just become active. */
7542                         if (!tmp->rdev
7543                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
7544                                 count++;
7545                         if (tmp->rdev) {
7546                                 /* Replaced device not technically faulty,
7547                                  * but we need to be sure it gets removed
7548                                  * and never re-added.
7549                                  */
7550                                 set_bit(Faulty, &tmp->rdev->flags);
7551                                 sysfs_notify_dirent_safe(
7552                                         tmp->rdev->sysfs_state);
7553                         }
7554                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
7555                 } else if (tmp->rdev
7556                     && tmp->rdev->recovery_offset == MaxSector
7557                     && !test_bit(Faulty, &tmp->rdev->flags)
7558                     && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
7559                         count++;
7560                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
7561                 }
7562         }
7563         spin_lock_irqsave(&conf->device_lock, flags);
7564         mddev->degraded = raid5_calc_degraded(conf);
7565         spin_unlock_irqrestore(&conf->device_lock, flags);
7566         print_raid5_conf(conf);
7567         return count;
7568 }
7569
7570 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
7571 {
7572         struct r5conf *conf = mddev->private;
7573         int err = 0;
7574         int number = rdev->raid_disk;
7575         struct md_rdev **rdevp;
7576         struct disk_info *p = conf->disks + number;
7577
7578         print_raid5_conf(conf);
7579         if (test_bit(Journal, &rdev->flags) && conf->log) {
7580                 /*
7581                  * we can't wait pending write here, as this is called in
7582                  * raid5d, wait will deadlock.
7583                  * neilb: there is no locking about new writes here,
7584                  * so this cannot be safe.
7585                  */
7586                 if (atomic_read(&conf->active_stripes) ||
7587                     atomic_read(&conf->r5c_cached_full_stripes) ||
7588                     atomic_read(&conf->r5c_cached_partial_stripes)) {
7589                         return -EBUSY;
7590                 }
7591                 log_exit(conf);
7592                 return 0;
7593         }
7594         if (rdev == p->rdev)
7595                 rdevp = &p->rdev;
7596         else if (rdev == p->replacement)
7597                 rdevp = &p->replacement;
7598         else
7599                 return 0;
7600
7601         if (number >= conf->raid_disks &&
7602             conf->reshape_progress == MaxSector)
7603                 clear_bit(In_sync, &rdev->flags);
7604
7605         if (test_bit(In_sync, &rdev->flags) ||
7606             atomic_read(&rdev->nr_pending)) {
7607                 err = -EBUSY;
7608                 goto abort;
7609         }
7610         /* Only remove non-faulty devices if recovery
7611          * isn't possible.
7612          */
7613         if (!test_bit(Faulty, &rdev->flags) &&
7614             mddev->recovery_disabled != conf->recovery_disabled &&
7615             !has_failed(conf) &&
7616             (!p->replacement || p->replacement == rdev) &&
7617             number < conf->raid_disks) {
7618                 err = -EBUSY;
7619                 goto abort;
7620         }
7621         *rdevp = NULL;
7622         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
7623                 synchronize_rcu();
7624                 if (atomic_read(&rdev->nr_pending)) {
7625                         /* lost the race, try later */
7626                         err = -EBUSY;
7627                         *rdevp = rdev;
7628                 }
7629         }
7630         if (!err) {
7631                 err = log_modify(conf, rdev, false);
7632                 if (err)
7633                         goto abort;
7634         }
7635         if (p->replacement) {
7636                 /* We must have just cleared 'rdev' */
7637                 p->rdev = p->replacement;
7638                 clear_bit(Replacement, &p->replacement->flags);
7639                 smp_mb(); /* Make sure other CPUs may see both as identical
7640                            * but will never see neither - if they are careful
7641                            */
7642                 p->replacement = NULL;
7643
7644                 if (!err)
7645                         err = log_modify(conf, p->rdev, true);
7646         }
7647
7648         clear_bit(WantReplacement, &rdev->flags);
7649 abort:
7650
7651         print_raid5_conf(conf);
7652         return err;
7653 }
7654
7655 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
7656 {
7657         struct r5conf *conf = mddev->private;
7658         int err = -EEXIST;
7659         int disk;
7660         struct disk_info *p;
7661         int first = 0;
7662         int last = conf->raid_disks - 1;
7663
7664         if (test_bit(Journal, &rdev->flags)) {
7665                 if (conf->log)
7666                         return -EBUSY;
7667
7668                 rdev->raid_disk = 0;
7669                 /*
7670                  * The array is in readonly mode if journal is missing, so no
7671                  * write requests running. We should be safe
7672                  */
7673                 log_init(conf, rdev, false);
7674                 return 0;
7675         }
7676         if (mddev->recovery_disabled == conf->recovery_disabled)
7677                 return -EBUSY;
7678
7679         if (rdev->saved_raid_disk < 0 && has_failed(conf))
7680                 /* no point adding a device */
7681                 return -EINVAL;
7682
7683         if (rdev->raid_disk >= 0)
7684                 first = last = rdev->raid_disk;
7685
7686         /*
7687          * find the disk ... but prefer rdev->saved_raid_disk
7688          * if possible.
7689          */
7690         if (rdev->saved_raid_disk >= 0 &&
7691             rdev->saved_raid_disk >= first &&
7692             conf->disks[rdev->saved_raid_disk].rdev == NULL)
7693                 first = rdev->saved_raid_disk;
7694
7695         for (disk = first; disk <= last; disk++) {
7696                 p = conf->disks + disk;
7697                 if (p->rdev == NULL) {
7698                         clear_bit(In_sync, &rdev->flags);
7699                         rdev->raid_disk = disk;
7700                         if (rdev->saved_raid_disk != disk)
7701                                 conf->fullsync = 1;
7702                         rcu_assign_pointer(p->rdev, rdev);
7703
7704                         err = log_modify(conf, rdev, true);
7705
7706                         goto out;
7707                 }
7708         }
7709         for (disk = first; disk <= last; disk++) {
7710                 p = conf->disks + disk;
7711                 if (test_bit(WantReplacement, &p->rdev->flags) &&
7712                     p->replacement == NULL) {
7713                         clear_bit(In_sync, &rdev->flags);
7714                         set_bit(Replacement, &rdev->flags);
7715                         rdev->raid_disk = disk;
7716                         err = 0;
7717                         conf->fullsync = 1;
7718                         rcu_assign_pointer(p->replacement, rdev);
7719                         break;
7720                 }
7721         }
7722 out:
7723         print_raid5_conf(conf);
7724         return err;
7725 }
7726
7727 static int raid5_resize(struct mddev *mddev, sector_t sectors)
7728 {
7729         /* no resync is happening, and there is enough space
7730          * on all devices, so we can resize.
7731          * We need to make sure resync covers any new space.
7732          * If the array is shrinking we should possibly wait until
7733          * any io in the removed space completes, but it hardly seems
7734          * worth it.
7735          */
7736         sector_t newsize;
7737         struct r5conf *conf = mddev->private;
7738
7739         if (raid5_has_log(conf) || raid5_has_ppl(conf))
7740                 return -EINVAL;
7741         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7742         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
7743         if (mddev->external_size &&
7744             mddev->array_sectors > newsize)
7745                 return -EINVAL;
7746         if (mddev->bitmap) {
7747                 int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
7748                 if (ret)
7749                         return ret;
7750         }
7751         md_set_array_sectors(mddev, newsize);
7752         if (sectors > mddev->dev_sectors &&
7753             mddev->recovery_cp > mddev->dev_sectors) {
7754                 mddev->recovery_cp = mddev->dev_sectors;
7755                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7756         }
7757         mddev->dev_sectors = sectors;
7758         mddev->resync_max_sectors = sectors;
7759         return 0;
7760 }
7761
7762 static int check_stripe_cache(struct mddev *mddev)
7763 {
7764         /* Can only proceed if there are plenty of stripe_heads.
7765          * We need a minimum of one full stripe,, and for sensible progress
7766          * it is best to have about 4 times that.
7767          * If we require 4 times, then the default 256 4K stripe_heads will
7768          * allow for chunk sizes up to 256K, which is probably OK.
7769          * If the chunk size is greater, user-space should request more
7770          * stripe_heads first.
7771          */
7772         struct r5conf *conf = mddev->private;
7773         if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
7774             > conf->min_nr_stripes ||
7775             ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
7776             > conf->min_nr_stripes) {
7777                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
7778                         mdname(mddev),
7779                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
7780                          / STRIPE_SIZE)*4);
7781                 return 0;
7782         }
7783         return 1;
7784 }
7785
7786 static int check_reshape(struct mddev *mddev)
7787 {
7788         struct r5conf *conf = mddev->private;
7789
7790         if (raid5_has_log(conf) || raid5_has_ppl(conf))
7791                 return -EINVAL;
7792         if (mddev->delta_disks == 0 &&
7793             mddev->new_layout == mddev->layout &&
7794             mddev->new_chunk_sectors == mddev->chunk_sectors)
7795                 return 0; /* nothing to do */
7796         if (has_failed(conf))
7797                 return -EINVAL;
7798         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
7799                 /* We might be able to shrink, but the devices must
7800                  * be made bigger first.
7801                  * For raid6, 4 is the minimum size.
7802                  * Otherwise 2 is the minimum
7803                  */
7804                 int min = 2;
7805                 if (mddev->level == 6)
7806                         min = 4;
7807                 if (mddev->raid_disks + mddev->delta_disks < min)
7808                         return -EINVAL;
7809         }
7810
7811         if (!check_stripe_cache(mddev))
7812                 return -ENOSPC;
7813
7814         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
7815             mddev->delta_disks > 0)
7816                 if (resize_chunks(conf,
7817                                   conf->previous_raid_disks
7818                                   + max(0, mddev->delta_disks),
7819                                   max(mddev->new_chunk_sectors,
7820                                       mddev->chunk_sectors)
7821                             ) < 0)
7822                         return -ENOMEM;
7823
7824         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
7825                 return 0; /* never bother to shrink */
7826         return resize_stripes(conf, (conf->previous_raid_disks
7827                                      + mddev->delta_disks));
7828 }
7829
7830 static int raid5_start_reshape(struct mddev *mddev)
7831 {
7832         struct r5conf *conf = mddev->private;
7833         struct md_rdev *rdev;
7834         int spares = 0;
7835         unsigned long flags;
7836
7837         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
7838                 return -EBUSY;
7839
7840         if (!check_stripe_cache(mddev))
7841                 return -ENOSPC;
7842
7843         if (has_failed(conf))
7844                 return -EINVAL;
7845
7846         rdev_for_each(rdev, mddev) {
7847                 if (!test_bit(In_sync, &rdev->flags)
7848                     && !test_bit(Faulty, &rdev->flags))
7849                         spares++;
7850         }
7851
7852         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
7853                 /* Not enough devices even to make a degraded array
7854                  * of that size
7855                  */
7856                 return -EINVAL;
7857
7858         /* Refuse to reduce size of the array.  Any reductions in
7859          * array size must be through explicit setting of array_size
7860          * attribute.
7861          */
7862         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
7863             < mddev->array_sectors) {
7864                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
7865                         mdname(mddev));
7866                 return -EINVAL;
7867         }
7868
7869         atomic_set(&conf->reshape_stripes, 0);
7870         spin_lock_irq(&conf->device_lock);
7871         write_seqcount_begin(&conf->gen_lock);
7872         conf->previous_raid_disks = conf->raid_disks;
7873         conf->raid_disks += mddev->delta_disks;
7874         conf->prev_chunk_sectors = conf->chunk_sectors;
7875         conf->chunk_sectors = mddev->new_chunk_sectors;
7876         conf->prev_algo = conf->algorithm;
7877         conf->algorithm = mddev->new_layout;
7878         conf->generation++;
7879         /* Code that selects data_offset needs to see the generation update
7880          * if reshape_progress has been set - so a memory barrier needed.
7881          */
7882         smp_mb();
7883         if (mddev->reshape_backwards)
7884                 conf->reshape_progress = raid5_size(mddev, 0, 0);
7885         else
7886                 conf->reshape_progress = 0;
7887         conf->reshape_safe = conf->reshape_progress;
7888         write_seqcount_end(&conf->gen_lock);
7889         spin_unlock_irq(&conf->device_lock);
7890
7891         /* Now make sure any requests that proceeded on the assumption
7892          * the reshape wasn't running - like Discard or Read - have
7893          * completed.
7894          */
7895         mddev_suspend(mddev);
7896         mddev_resume(mddev);
7897
7898         /* Add some new drives, as many as will fit.
7899          * We know there are enough to make the newly sized array work.
7900          * Don't add devices if we are reducing the number of
7901          * devices in the array.  This is because it is not possible
7902          * to correctly record the "partially reconstructed" state of
7903          * such devices during the reshape and confusion could result.
7904          */
7905         if (mddev->delta_disks >= 0) {
7906                 rdev_for_each(rdev, mddev)
7907                         if (rdev->raid_disk < 0 &&
7908                             !test_bit(Faulty, &rdev->flags)) {
7909                                 if (raid5_add_disk(mddev, rdev) == 0) {
7910                                         if (rdev->raid_disk
7911                                             >= conf->previous_raid_disks)
7912                                                 set_bit(In_sync, &rdev->flags);
7913                                         else
7914                                                 rdev->recovery_offset = 0;
7915
7916                                         if (sysfs_link_rdev(mddev, rdev))
7917                                                 /* Failure here is OK */;
7918                                 }
7919                         } else if (rdev->raid_disk >= conf->previous_raid_disks
7920                                    && !test_bit(Faulty, &rdev->flags)) {
7921                                 /* This is a spare that was manually added */
7922                                 set_bit(In_sync, &rdev->flags);
7923                         }
7924
7925                 /* When a reshape changes the number of devices,
7926                  * ->degraded is measured against the larger of the
7927                  * pre and post number of devices.
7928                  */
7929                 spin_lock_irqsave(&conf->device_lock, flags);
7930                 mddev->degraded = raid5_calc_degraded(conf);
7931                 spin_unlock_irqrestore(&conf->device_lock, flags);
7932         }
7933         mddev->raid_disks = conf->raid_disks;
7934         mddev->reshape_position = conf->reshape_progress;
7935         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
7936
7937         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7938         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7939         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7940         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7941         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7942         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7943                                                 "reshape");
7944         if (!mddev->sync_thread) {
7945                 mddev->recovery = 0;
7946                 spin_lock_irq(&conf->device_lock);
7947                 write_seqcount_begin(&conf->gen_lock);
7948                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
7949                 mddev->new_chunk_sectors =
7950                         conf->chunk_sectors = conf->prev_chunk_sectors;
7951                 mddev->new_layout = conf->algorithm = conf->prev_algo;
7952                 rdev_for_each(rdev, mddev)
7953                         rdev->new_data_offset = rdev->data_offset;
7954                 smp_wmb();
7955                 conf->generation --;
7956                 conf->reshape_progress = MaxSector;
7957                 mddev->reshape_position = MaxSector;
7958                 write_seqcount_end(&conf->gen_lock);
7959                 spin_unlock_irq(&conf->device_lock);
7960                 return -EAGAIN;
7961         }
7962         conf->reshape_checkpoint = jiffies;
7963         md_wakeup_thread(mddev->sync_thread);
7964         md_new_event(mddev);
7965         return 0;
7966 }
7967
7968 /* This is called from the reshape thread and should make any
7969  * changes needed in 'conf'
7970  */
7971 static void end_reshape(struct r5conf *conf)
7972 {
7973
7974         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
7975
7976                 spin_lock_irq(&conf->device_lock);
7977                 conf->previous_raid_disks = conf->raid_disks;
7978                 md_finish_reshape(conf->mddev);
7979                 smp_wmb();
7980                 conf->reshape_progress = MaxSector;
7981                 conf->mddev->reshape_position = MaxSector;
7982                 spin_unlock_irq(&conf->device_lock);
7983                 wake_up(&conf->wait_for_overlap);
7984
7985                 /* read-ahead size must cover two whole stripes, which is
7986                  * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
7987                  */
7988                 if (conf->mddev->queue) {
7989                         int data_disks = conf->raid_disks - conf->max_degraded;
7990                         int stripe = data_disks * ((conf->chunk_sectors << 9)
7991                                                    / PAGE_SIZE);
7992                         if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7993                                 conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7994                 }
7995         }
7996 }
7997
7998 /* This is called from the raid5d thread with mddev_lock held.
7999  * It makes config changes to the device.
8000  */
8001 static void raid5_finish_reshape(struct mddev *mddev)
8002 {
8003         struct r5conf *conf = mddev->private;
8004
8005         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8006
8007                 if (mddev->delta_disks <= 0) {
8008                         int d;
8009                         spin_lock_irq(&conf->device_lock);
8010                         mddev->degraded = raid5_calc_degraded(conf);
8011                         spin_unlock_irq(&conf->device_lock);
8012                         for (d = conf->raid_disks ;
8013                              d < conf->raid_disks - mddev->delta_disks;
8014                              d++) {
8015                                 struct md_rdev *rdev = conf->disks[d].rdev;
8016                                 if (rdev)
8017                                         clear_bit(In_sync, &rdev->flags);
8018                                 rdev = conf->disks[d].replacement;
8019                                 if (rdev)
8020                                         clear_bit(In_sync, &rdev->flags);
8021                         }
8022                 }
8023                 mddev->layout = conf->algorithm;
8024                 mddev->chunk_sectors = conf->chunk_sectors;
8025                 mddev->reshape_position = MaxSector;
8026                 mddev->delta_disks = 0;
8027                 mddev->reshape_backwards = 0;
8028         }
8029 }
8030
8031 static void raid5_quiesce(struct mddev *mddev, int quiesce)
8032 {
8033         struct r5conf *conf = mddev->private;
8034
8035         if (quiesce) {
8036                 /* stop all writes */
8037                 lock_all_device_hash_locks_irq(conf);
8038                 /* '2' tells resync/reshape to pause so that all
8039                  * active stripes can drain
8040                  */
8041                 r5c_flush_cache(conf, INT_MAX);
8042                 conf->quiesce = 2;
8043                 wait_event_cmd(conf->wait_for_quiescent,
8044                                     atomic_read(&conf->active_stripes) == 0 &&
8045                                     atomic_read(&conf->active_aligned_reads) == 0,
8046                                     unlock_all_device_hash_locks_irq(conf),
8047                                     lock_all_device_hash_locks_irq(conf));
8048                 conf->quiesce = 1;
8049                 unlock_all_device_hash_locks_irq(conf);
8050                 /* allow reshape to continue */
8051                 wake_up(&conf->wait_for_overlap);
8052         } else {
8053                 /* re-enable writes */
8054                 lock_all_device_hash_locks_irq(conf);
8055                 conf->quiesce = 0;
8056                 wake_up(&conf->wait_for_quiescent);
8057                 wake_up(&conf->wait_for_overlap);
8058                 unlock_all_device_hash_locks_irq(conf);
8059         }
8060         r5l_quiesce(conf->log, quiesce);
8061 }
8062
8063 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8064 {
8065         struct r0conf *raid0_conf = mddev->private;
8066         sector_t sectors;
8067
8068         /* for raid0 takeover only one zone is supported */
8069         if (raid0_conf->nr_strip_zones > 1) {
8070                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8071                         mdname(mddev));
8072                 return ERR_PTR(-EINVAL);
8073         }
8074
8075         sectors = raid0_conf->strip_zone[0].zone_end;
8076         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8077         mddev->dev_sectors = sectors;
8078         mddev->new_level = level;
8079         mddev->new_layout = ALGORITHM_PARITY_N;
8080         mddev->new_chunk_sectors = mddev->chunk_sectors;
8081         mddev->raid_disks += 1;
8082         mddev->delta_disks = 1;
8083         /* make sure it will be not marked as dirty */
8084         mddev->recovery_cp = MaxSector;
8085
8086         return setup_conf(mddev);
8087 }
8088
8089 static void *raid5_takeover_raid1(struct mddev *mddev)
8090 {
8091         int chunksect;
8092         void *ret;
8093
8094         if (mddev->raid_disks != 2 ||
8095             mddev->degraded > 1)
8096                 return ERR_PTR(-EINVAL);
8097
8098         /* Should check if there are write-behind devices? */
8099
8100         chunksect = 64*2; /* 64K by default */
8101
8102         /* The array must be an exact multiple of chunksize */
8103         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8104                 chunksect >>= 1;
8105
8106         if ((chunksect<<9) < STRIPE_SIZE)
8107                 /* array size does not allow a suitable chunk size */
8108                 return ERR_PTR(-EINVAL);
8109
8110         mddev->new_level = 5;
8111         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8112         mddev->new_chunk_sectors = chunksect;
8113
8114         ret = setup_conf(mddev);
8115         if (!IS_ERR(ret))
8116                 mddev_clear_unsupported_flags(mddev,
8117                         UNSUPPORTED_MDDEV_FLAGS);
8118         return ret;
8119 }
8120
8121 static void *raid5_takeover_raid6(struct mddev *mddev)
8122 {
8123         int new_layout;
8124
8125         switch (mddev->layout) {
8126         case ALGORITHM_LEFT_ASYMMETRIC_6:
8127                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8128                 break;
8129         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8130                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8131                 break;
8132         case ALGORITHM_LEFT_SYMMETRIC_6:
8133                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8134                 break;
8135         case ALGORITHM_RIGHT_SYMMETRIC_6:
8136                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8137                 break;
8138         case ALGORITHM_PARITY_0_6:
8139                 new_layout = ALGORITHM_PARITY_0;
8140                 break;
8141         case ALGORITHM_PARITY_N:
8142                 new_layout = ALGORITHM_PARITY_N;
8143                 break;
8144         default:
8145                 return ERR_PTR(-EINVAL);
8146         }
8147         mddev->new_level = 5;
8148         mddev->new_layout = new_layout;
8149         mddev->delta_disks = -1;
8150         mddev->raid_disks -= 1;
8151         return setup_conf(mddev);
8152 }
8153
8154 static int raid5_check_reshape(struct mddev *mddev)
8155 {
8156         /* For a 2-drive array, the layout and chunk size can be changed
8157          * immediately as not restriping is needed.
8158          * For larger arrays we record the new value - after validation
8159          * to be used by a reshape pass.
8160          */
8161         struct r5conf *conf = mddev->private;
8162         int new_chunk = mddev->new_chunk_sectors;
8163
8164         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8165                 return -EINVAL;
8166         if (new_chunk > 0) {
8167                 if (!is_power_of_2(new_chunk))
8168                         return -EINVAL;
8169                 if (new_chunk < (PAGE_SIZE>>9))
8170                         return -EINVAL;
8171                 if (mddev->array_sectors & (new_chunk-1))
8172                         /* not factor of array size */
8173                         return -EINVAL;
8174         }
8175
8176         /* They look valid */
8177
8178         if (mddev->raid_disks == 2) {
8179                 /* can make the change immediately */
8180                 if (mddev->new_layout >= 0) {
8181                         conf->algorithm = mddev->new_layout;
8182                         mddev->layout = mddev->new_layout;
8183                 }
8184                 if (new_chunk > 0) {
8185                         conf->chunk_sectors = new_chunk ;
8186                         mddev->chunk_sectors = new_chunk;
8187                 }
8188                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8189                 md_wakeup_thread(mddev->thread);
8190         }
8191         return check_reshape(mddev);
8192 }
8193
8194 static int raid6_check_reshape(struct mddev *mddev)
8195 {
8196         int new_chunk = mddev->new_chunk_sectors;
8197
8198         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8199                 return -EINVAL;
8200         if (new_chunk > 0) {
8201                 if (!is_power_of_2(new_chunk))
8202                         return -EINVAL;
8203                 if (new_chunk < (PAGE_SIZE >> 9))
8204                         return -EINVAL;
8205                 if (mddev->array_sectors & (new_chunk-1))
8206                         /* not factor of array size */
8207                         return -EINVAL;
8208         }
8209
8210         /* They look valid */
8211         return check_reshape(mddev);
8212 }
8213
8214 static void *raid5_takeover(struct mddev *mddev)
8215 {
8216         /* raid5 can take over:
8217          *  raid0 - if there is only one strip zone - make it a raid4 layout
8218          *  raid1 - if there are two drives.  We need to know the chunk size
8219          *  raid4 - trivial - just use a raid4 layout.
8220          *  raid6 - Providing it is a *_6 layout
8221          */
8222         if (mddev->level == 0)
8223                 return raid45_takeover_raid0(mddev, 5);
8224         if (mddev->level == 1)
8225                 return raid5_takeover_raid1(mddev);
8226         if (mddev->level == 4) {
8227                 mddev->new_layout = ALGORITHM_PARITY_N;
8228                 mddev->new_level = 5;
8229                 return setup_conf(mddev);
8230         }
8231         if (mddev->level == 6)
8232                 return raid5_takeover_raid6(mddev);
8233
8234         return ERR_PTR(-EINVAL);
8235 }
8236
8237 static void *raid4_takeover(struct mddev *mddev)
8238 {
8239         /* raid4 can take over:
8240          *  raid0 - if there is only one strip zone
8241          *  raid5 - if layout is right
8242          */
8243         if (mddev->level == 0)
8244                 return raid45_takeover_raid0(mddev, 4);
8245         if (mddev->level == 5 &&
8246             mddev->layout == ALGORITHM_PARITY_N) {
8247                 mddev->new_layout = 0;
8248                 mddev->new_level = 4;
8249                 return setup_conf(mddev);
8250         }
8251         return ERR_PTR(-EINVAL);
8252 }
8253
8254 static struct md_personality raid5_personality;
8255
8256 static void *raid6_takeover(struct mddev *mddev)
8257 {
8258         /* Currently can only take over a raid5.  We map the
8259          * personality to an equivalent raid6 personality
8260          * with the Q block at the end.
8261          */
8262         int new_layout;
8263
8264         if (mddev->pers != &raid5_personality)
8265                 return ERR_PTR(-EINVAL);
8266         if (mddev->degraded > 1)
8267                 return ERR_PTR(-EINVAL);
8268         if (mddev->raid_disks > 253)
8269                 return ERR_PTR(-EINVAL);
8270         if (mddev->raid_disks < 3)
8271                 return ERR_PTR(-EINVAL);
8272
8273         switch (mddev->layout) {
8274         case ALGORITHM_LEFT_ASYMMETRIC:
8275                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8276                 break;
8277         case ALGORITHM_RIGHT_ASYMMETRIC:
8278                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8279                 break;
8280         case ALGORITHM_LEFT_SYMMETRIC:
8281                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8282                 break;
8283         case ALGORITHM_RIGHT_SYMMETRIC:
8284                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8285                 break;
8286         case ALGORITHM_PARITY_0:
8287                 new_layout = ALGORITHM_PARITY_0_6;
8288                 break;
8289         case ALGORITHM_PARITY_N:
8290                 new_layout = ALGORITHM_PARITY_N;
8291                 break;
8292         default:
8293                 return ERR_PTR(-EINVAL);
8294         }
8295         mddev->new_level = 6;
8296         mddev->new_layout = new_layout;
8297         mddev->delta_disks = 1;
8298         mddev->raid_disks += 1;
8299         return setup_conf(mddev);
8300 }
8301
8302 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8303 {
8304         struct r5conf *conf;
8305         int err;
8306
8307         err = mddev_lock(mddev);
8308         if (err)
8309                 return err;
8310         conf = mddev->private;
8311         if (!conf) {
8312                 mddev_unlock(mddev);
8313                 return -ENODEV;
8314         }
8315
8316         if (strncmp(buf, "ppl", 3) == 0) {
8317                 /* ppl only works with RAID 5 */
8318                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8319                         err = log_init(conf, NULL, true);
8320                         if (!err) {
8321                                 err = resize_stripes(conf, conf->pool_size);
8322                                 if (err)
8323                                         log_exit(conf);
8324                         }
8325                 } else
8326                         err = -EINVAL;
8327         } else if (strncmp(buf, "resync", 6) == 0) {
8328                 if (raid5_has_ppl(conf)) {
8329                         mddev_suspend(mddev);
8330                         log_exit(conf);
8331                         mddev_resume(mddev);
8332                         err = resize_stripes(conf, conf->pool_size);
8333                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8334                            r5l_log_disk_error(conf)) {
8335                         bool journal_dev_exists = false;
8336                         struct md_rdev *rdev;
8337
8338                         rdev_for_each(rdev, mddev)
8339                                 if (test_bit(Journal, &rdev->flags)) {
8340                                         journal_dev_exists = true;
8341                                         break;
8342                                 }
8343
8344                         if (!journal_dev_exists) {
8345                                 mddev_suspend(mddev);
8346                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8347                                 mddev_resume(mddev);
8348                         } else  /* need remove journal device first */
8349                                 err = -EBUSY;
8350                 } else
8351                         err = -EINVAL;
8352         } else {
8353                 err = -EINVAL;
8354         }
8355
8356         if (!err)
8357                 md_update_sb(mddev, 1);
8358
8359         mddev_unlock(mddev);
8360
8361         return err;
8362 }
8363
8364 static struct md_personality raid6_personality =
8365 {
8366         .name           = "raid6",
8367         .level          = 6,
8368         .owner          = THIS_MODULE,
8369         .make_request   = raid5_make_request,
8370         .run            = raid5_run,
8371         .free           = raid5_free,
8372         .status         = raid5_status,
8373         .error_handler  = raid5_error,
8374         .hot_add_disk   = raid5_add_disk,
8375         .hot_remove_disk= raid5_remove_disk,
8376         .spare_active   = raid5_spare_active,
8377         .sync_request   = raid5_sync_request,
8378         .resize         = raid5_resize,
8379         .size           = raid5_size,
8380         .check_reshape  = raid6_check_reshape,
8381         .start_reshape  = raid5_start_reshape,
8382         .finish_reshape = raid5_finish_reshape,
8383         .quiesce        = raid5_quiesce,
8384         .takeover       = raid6_takeover,
8385         .congested      = raid5_congested,
8386         .change_consistency_policy = raid5_change_consistency_policy,
8387 };
8388 static struct md_personality raid5_personality =
8389 {
8390         .name           = "raid5",
8391         .level          = 5,
8392         .owner          = THIS_MODULE,
8393         .make_request   = raid5_make_request,
8394         .run            = raid5_run,
8395         .free           = raid5_free,
8396         .status         = raid5_status,
8397         .error_handler  = raid5_error,
8398         .hot_add_disk   = raid5_add_disk,
8399         .hot_remove_disk= raid5_remove_disk,
8400         .spare_active   = raid5_spare_active,
8401         .sync_request   = raid5_sync_request,
8402         .resize         = raid5_resize,
8403         .size           = raid5_size,
8404         .check_reshape  = raid5_check_reshape,
8405         .start_reshape  = raid5_start_reshape,
8406         .finish_reshape = raid5_finish_reshape,
8407         .quiesce        = raid5_quiesce,
8408         .takeover       = raid5_takeover,
8409         .congested      = raid5_congested,
8410         .change_consistency_policy = raid5_change_consistency_policy,
8411 };
8412
8413 static struct md_personality raid4_personality =
8414 {
8415         .name           = "raid4",
8416         .level          = 4,
8417         .owner          = THIS_MODULE,
8418         .make_request   = raid5_make_request,
8419         .run            = raid5_run,
8420         .free           = raid5_free,
8421         .status         = raid5_status,
8422         .error_handler  = raid5_error,
8423         .hot_add_disk   = raid5_add_disk,
8424         .hot_remove_disk= raid5_remove_disk,
8425         .spare_active   = raid5_spare_active,
8426         .sync_request   = raid5_sync_request,
8427         .resize         = raid5_resize,
8428         .size           = raid5_size,
8429         .check_reshape  = raid5_check_reshape,
8430         .start_reshape  = raid5_start_reshape,
8431         .finish_reshape = raid5_finish_reshape,
8432         .quiesce        = raid5_quiesce,
8433         .takeover       = raid4_takeover,
8434         .congested      = raid5_congested,
8435         .change_consistency_policy = raid5_change_consistency_policy,
8436 };
8437
8438 static int __init raid5_init(void)
8439 {
8440         int ret;
8441
8442         raid5_wq = alloc_workqueue("raid5wq",
8443                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
8444         if (!raid5_wq)
8445                 return -ENOMEM;
8446
8447         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
8448                                       "md/raid5:prepare",
8449                                       raid456_cpu_up_prepare,
8450                                       raid456_cpu_dead);
8451         if (ret) {
8452                 destroy_workqueue(raid5_wq);
8453                 return ret;
8454         }
8455         register_md_personality(&raid6_personality);
8456         register_md_personality(&raid5_personality);
8457         register_md_personality(&raid4_personality);
8458         return 0;
8459 }
8460
8461 static void raid5_exit(void)
8462 {
8463         unregister_md_personality(&raid6_personality);
8464         unregister_md_personality(&raid5_personality);
8465         unregister_md_personality(&raid4_personality);
8466         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
8467         destroy_workqueue(raid5_wq);
8468 }
8469
8470 module_init(raid5_init);
8471 module_exit(raid5_exit);
8472 MODULE_LICENSE("GPL");
8473 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
8474 MODULE_ALIAS("md-personality-4"); /* RAID5 */
8475 MODULE_ALIAS("md-raid5");
8476 MODULE_ALIAS("md-raid4");
8477 MODULE_ALIAS("md-level-5");
8478 MODULE_ALIAS("md-level-4");
8479 MODULE_ALIAS("md-personality-8"); /* RAID6 */
8480 MODULE_ALIAS("md-raid6");
8481 MODULE_ALIAS("md-level-6");
8482
8483 /* This used to be two separate modules, they were: */
8484 MODULE_ALIAS("raid5");
8485 MODULE_ALIAS("raid6");