fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/random.h>
  24 #include <linux/iocontext.h>
  25 #include <linux/capability.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include <linux/raid/pq.h>
  29 #include <linux/semaphore.h>
  30 #include <asm/div64.h>
  31 #include "ctree.h"
  32 #include "extent_map.h"
  33 #include "disk-io.h"
  34 #include "transaction.h"
  35 #include "print-tree.h"
  36 #include "volumes.h"
  37 #include "raid56.h"
  38 #include "async-thread.h"
  39 #include "check-integrity.h"
  40 #include "rcu-string.h"
  41 #include "math.h"
  42 #include "dev-replace.h"
  43 #include "sysfs.h"
  44
  45 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
  46         [BTRFS_RAID_RAID10] = {
  47                 .sub_stripes    = 2,
  48                 .dev_stripes    = 1,
  49                 .devs_max       = 0,    /* 0 == as many as possible */
  50                 .devs_min       = 4,
  51                 .tolerated_failures = 1,
  52                 .devs_increment = 2,
  53                 .ncopies        = 2,
  54         },
  55         [BTRFS_RAID_RAID1] = {
  56                 .sub_stripes    = 1,
  57                 .dev_stripes    = 1,
  58                 .devs_max       = 2,
  59                 .devs_min       = 2,
  60                 .tolerated_failures = 1,
  61                 .devs_increment = 2,
  62                 .ncopies        = 2,
  63         },
  64         [BTRFS_RAID_DUP] = {
  65                 .sub_stripes    = 1,
  66                 .dev_stripes    = 2,
  67                 .devs_max       = 1,
  68                 .devs_min       = 1,
  69                 .tolerated_failures = 0,
  70                 .devs_increment = 1,
  71                 .ncopies        = 2,
  72         },
  73         [BTRFS_RAID_RAID0] = {
  74                 .sub_stripes    = 1,
  75                 .dev_stripes    = 1,
  76                 .devs_max       = 0,
  77                 .devs_min       = 2,
  78                 .tolerated_failures = 0,
  79                 .devs_increment = 1,
  80                 .ncopies        = 1,
  81         },
  82         [BTRFS_RAID_SINGLE] = {
  83                 .sub_stripes    = 1,
  84                 .dev_stripes    = 1,
  85                 .devs_max       = 1,
  86                 .devs_min       = 1,
  87                 .tolerated_failures = 0,
  88                 .devs_increment = 1,
  89                 .ncopies        = 1,
  90         },
  91         [BTRFS_RAID_RAID5] = {
  92                 .sub_stripes    = 1,
  93                 .dev_stripes    = 1,
  94                 .devs_max       = 0,
  95                 .devs_min       = 2,
  96                 .tolerated_failures = 1,
  97                 .devs_increment = 1,
  98                 .ncopies        = 2,
  99         },
 100         [BTRFS_RAID_RAID6] = {
 101                 .sub_stripes    = 1,
 102                 .dev_stripes    = 1,
 103                 .devs_max       = 0,
 104                 .devs_min       = 3,
 105                 .tolerated_failures = 2,
 106                 .devs_increment = 1,
 107                 .ncopies        = 3,
 108         },
 109 };
 110
 111 const u64 btrfs_raid_group[BTRFS_NR_RAID_TYPES] = {
 112         [BTRFS_RAID_RAID10] = BTRFS_BLOCK_GROUP_RAID10,
 113         [BTRFS_RAID_RAID1]  = BTRFS_BLOCK_GROUP_RAID1,
 114         [BTRFS_RAID_DUP]    = BTRFS_BLOCK_GROUP_DUP,
 115         [BTRFS_RAID_RAID0]  = BTRFS_BLOCK_GROUP_RAID0,
 116         [BTRFS_RAID_SINGLE] = 0,
 117         [BTRFS_RAID_RAID5]  = BTRFS_BLOCK_GROUP_RAID5,
 118         [BTRFS_RAID_RAID6]  = BTRFS_BLOCK_GROUP_RAID6,
 119 };
 120
 121 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 122                                 struct btrfs_root *root,
 123                                 struct btrfs_device *device);
 124 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
 125 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
 126 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev);
 127 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
 128
 129 DEFINE_MUTEX(uuid_mutex);
 130 static LIST_HEAD(fs_uuids);
 131 struct list_head *btrfs_get_fs_uuids(void)
 132 {
 133         return &fs_uuids;
 134 }
 135
 136 static struct btrfs_fs_devices *__alloc_fs_devices(void)
 137 {
 138         struct btrfs_fs_devices *fs_devs;
 139
 140         fs_devs = kzalloc(sizeof(*fs_devs), GFP_NOFS);
 141         if (!fs_devs)
 142                 return ERR_PTR(-ENOMEM);
 143
 144         mutex_init(&fs_devs->device_list_mutex);
 145
 146         INIT_LIST_HEAD(&fs_devs->devices);
 147         INIT_LIST_HEAD(&fs_devs->resized_devices);
 148         INIT_LIST_HEAD(&fs_devs->alloc_list);
 149         INIT_LIST_HEAD(&fs_devs->list);
 150
 151         return fs_devs;
 152 }
 153
 154 /**
 155  * alloc_fs_devices - allocate struct btrfs_fs_devices
 156  * @fsid:       a pointer to UUID for this FS.  If NULL a new UUID is
 157  *              generated.
 158  *
 159  * Return: a pointer to a new &struct btrfs_fs_devices on success;
 160  * ERR_PTR() on error.  Returned struct is not linked onto any lists and
 161  * can be destroyed with kfree() right away.
 162  */
 163 static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid)
 164 {
 165         struct btrfs_fs_devices *fs_devs;
 166
 167         fs_devs = __alloc_fs_devices();
 168         if (IS_ERR(fs_devs))
 169                 return fs_devs;
 170
 171         if (fsid)
 172                 memcpy(fs_devs->fsid, fsid, BTRFS_FSID_SIZE);
 173         else
 174                 generate_random_uuid(fs_devs->fsid);
 175
 176         return fs_devs;
 177 }
 178
 179 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
 180 {
 181         struct btrfs_device *device;
 182         WARN_ON(fs_devices->opened);
 183         while (!list_empty(&fs_devices->devices)) {
 184                 device = list_entry(fs_devices->devices.next,
 185                                     struct btrfs_device, dev_list);
 186                 list_del(&device->dev_list);
 187                 rcu_string_free(device->name);
 188                 kfree(device);
 189         }
 190         kfree(fs_devices);
 191 }
 192
 193 static void btrfs_kobject_uevent(struct block_device *bdev,
 194                                  enum kobject_action action)
 195 {
 196         int ret;
 197
 198         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
 199         if (ret)
 200                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
 201                         action,
 202                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
 203                         &disk_to_dev(bdev->bd_disk)->kobj);
 204 }
 205
 206 void btrfs_cleanup_fs_uuids(void)
 207 {
 208         struct btrfs_fs_devices *fs_devices;
 209
 210         while (!list_empty(&fs_uuids)) {
 211                 fs_devices = list_entry(fs_uuids.next,
 212                                         struct btrfs_fs_devices, list);
 213                 list_del(&fs_devices->list);
 214                 free_fs_devices(fs_devices);
 215         }
 216 }
 217
 218 static struct btrfs_device *__alloc_device(void)
 219 {
 220         struct btrfs_device *dev;
 221
 222         dev = kzalloc(sizeof(*dev), GFP_NOFS);
 223         if (!dev)
 224                 return ERR_PTR(-ENOMEM);
 225
 226         INIT_LIST_HEAD(&dev->dev_list);
 227         INIT_LIST_HEAD(&dev->dev_alloc_list);
 228         INIT_LIST_HEAD(&dev->resized_list);
 229
 230         spin_lock_init(&dev->io_lock);
 231
 232         spin_lock_init(&dev->reada_lock);
 233         atomic_set(&dev->reada_in_flight, 0);
 234         atomic_set(&dev->dev_stats_ccnt, 0);
 235         btrfs_device_data_ordered_init(dev);
 236         INIT_RADIX_TREE(&dev->reada_zones, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 237         INIT_RADIX_TREE(&dev->reada_extents, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 238
 239         return dev;
 240 }
 241
 242 static noinline struct btrfs_device *__find_device(struct list_head *head,
 243                                                    u64 devid, u8 *uuid)
 244 {
 245         struct btrfs_device *dev;
 246
 247         list_for_each_entry(dev, head, dev_list) {
 248                 if (dev->devid == devid &&
 249                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 250                         return dev;
 251                 }
 252         }
 253         return NULL;
 254 }
 255
 256 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 257 {
 258         struct btrfs_fs_devices *fs_devices;
 259
 260         list_for_each_entry(fs_devices, &fs_uuids, list) {
 261                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 262                         return fs_devices;
 263         }
 264         return NULL;
 265 }
 266
 267 static int
 268 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 269                       int flush, struct block_device **bdev,
 270                       struct buffer_head **bh)
 271 {
 272         int ret;
 273
 274         *bdev = blkdev_get_by_path(device_path, flags, holder);
 275
 276         if (IS_ERR(*bdev)) {
 277                 ret = PTR_ERR(*bdev);
 278                 goto error;
 279         }
 280
 281         if (flush)
 282                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 283         ret = set_blocksize(*bdev, 4096);
 284         if (ret) {
 285                 blkdev_put(*bdev, flags);
 286                 goto error;
 287         }
 288         invalidate_bdev(*bdev);
 289         *bh = btrfs_read_dev_super(*bdev);
 290         if (IS_ERR(*bh)) {
 291                 ret = PTR_ERR(*bh);
 292                 blkdev_put(*bdev, flags);
 293                 goto error;
 294         }
 295
 296         return 0;
 297
 298 error:
 299         *bdev = NULL;
 300         *bh = NULL;
 301         return ret;
 302 }
 303
 304 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 305                         struct bio *head, struct bio *tail)
 306 {
 307
 308         struct bio *old_head;
 309
 310         old_head = pending_bios->head;
 311         pending_bios->head = head;
 312         if (pending_bios->tail)
 313                 tail->bi_next = old_head;
 314         else
 315                 pending_bios->tail = tail;
 316 }
 317
 318 /*
 319  * we try to collect pending bios for a device so we don't get a large
 320  * number of procs sending bios down to the same device.  This greatly
 321  * improves the schedulers ability to collect and merge the bios.
 322  *
 323  * But, it also turns into a long list of bios to process and that is sure
 324  * to eventually make the worker thread block.  The solution here is to
 325  * make some progress and then put this work struct back at the end of
 326  * the list if the block device is congested.  This way, multiple devices
 327  * can make progress from a single worker thread.
 328  */
 329 static noinline void run_scheduled_bios(struct btrfs_device *device)
 330 {
 331         struct bio *pending;
 332         struct backing_dev_info *bdi;
 333         struct btrfs_fs_info *fs_info;
 334         struct btrfs_pending_bios *pending_bios;
 335         struct bio *tail;
 336         struct bio *cur;
 337         int again = 0;
 338         unsigned long num_run;
 339         unsigned long batch_run = 0;
 340         unsigned long limit;
 341         unsigned long last_waited = 0;
 342         int force_reg = 0;
 343         int sync_pending = 0;
 344         struct blk_plug plug;
 345
 346         /*
 347          * this function runs all the bios we've collected for
 348          * a particular device.  We don't want to wander off to
 349          * another device without first sending all of these down.
 350          * So, setup a plug here and finish it off before we return
 351          */
 352         blk_start_plug(&plug);
 353
 354         bdi = blk_get_backing_dev_info(device->bdev);
 355         fs_info = device->dev_root->fs_info;
 356         limit = btrfs_async_submit_limit(fs_info);
 357         limit = limit * 2 / 3;
 358
 359 loop:
 360         spin_lock(&device->io_lock);
 361
 362 loop_lock:
 363         num_run = 0;
 364
 365         /* take all the bios off the list at once and process them
 366          * later on (without the lock held).  But, remember the
 367          * tail and other pointers so the bios can be properly reinserted
 368          * into the list if we hit congestion
 369          */
 370         if (!force_reg && device->pending_sync_bios.head) {
 371                 pending_bios = &device->pending_sync_bios;
 372                 force_reg = 1;
 373         } else {
 374                 pending_bios = &device->pending_bios;
 375                 force_reg = 0;
 376         }
 377
 378         pending = pending_bios->head;
 379         tail = pending_bios->tail;
 380         WARN_ON(pending && !tail);
 381
 382         /*
 383          * if pending was null this time around, no bios need processing
 384          * at all and we can stop.  Otherwise it'll loop back up again
 385          * and do an additional check so no bios are missed.
 386          *
 387          * device->running_pending is used to synchronize with the
 388          * schedule_bio code.
 389          */
 390         if (device->pending_sync_bios.head == NULL &&
 391             device->pending_bios.head == NULL) {
 392                 again = 0;
 393                 device->running_pending = 0;
 394         } else {
 395                 again = 1;
 396                 device->running_pending = 1;
 397         }
 398
 399         pending_bios->head = NULL;
 400         pending_bios->tail = NULL;
 401
 402         spin_unlock(&device->io_lock);
 403
 404         while (pending) {
 405
 406                 rmb();
 407                 /* we want to work on both lists, but do more bios on the
 408                  * sync list than the regular list
 409                  */
 410                 if ((num_run > 32 &&
 411                     pending_bios != &device->pending_sync_bios &&
 412                     device->pending_sync_bios.head) ||
 413                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 414                     device->pending_bios.head)) {
 415                         spin_lock(&device->io_lock);
 416                         requeue_list(pending_bios, pending, tail);
 417                         goto loop_lock;
 418                 }
 419
 420                 cur = pending;
 421                 pending = pending->bi_next;
 422                 cur->bi_next = NULL;
 423
 424                 /*
 425                  * atomic_dec_return implies a barrier for waitqueue_active
 426                  */
 427                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 428                     waitqueue_active(&fs_info->async_submit_wait))
 429                         wake_up(&fs_info->async_submit_wait);
 430
 431                 BUG_ON(atomic_read(&cur->__bi_cnt) == 0);
 432
 433                 /*
 434                  * if we're doing the sync list, record that our
 435                  * plug has some sync requests on it
 436                  *
 437                  * If we're doing the regular list and there are
 438                  * sync requests sitting around, unplug before
 439                  * we add more
 440                  */
 441                 if (pending_bios == &device->pending_sync_bios) {
 442                         sync_pending = 1;
 443                 } else if (sync_pending) {
 444                         blk_finish_plug(&plug);
 445                         blk_start_plug(&plug);
 446                         sync_pending = 0;
 447                 }
 448
 449                 btrfsic_submit_bio(cur->bi_rw, cur);
 450                 num_run++;
 451                 batch_run++;
 452
 453                 cond_resched();
 454
 455                 /*
 456                  * we made progress, there is more work to do and the bdi
 457                  * is now congested.  Back off and let other work structs
 458                  * run instead
 459                  */
 460                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 461                     fs_info->fs_devices->open_devices > 1) {
 462                         struct io_context *ioc;
 463
 464                         ioc = current->io_context;
 465
 466                         /*
 467                          * the main goal here is that we don't want to
 468                          * block if we're going to be able to submit
 469                          * more requests without blocking.
 470                          *
 471                          * This code does two great things, it pokes into
 472                          * the elevator code from a filesystem _and_
 473                          * it makes assumptions about how batching works.
 474                          */
 475                         if (ioc && ioc->nr_batch_requests > 0 &&
 476                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 477                             (last_waited == 0 ||
 478                              ioc->last_waited == last_waited)) {
 479                                 /*
 480                                  * we want to go through our batch of
 481                                  * requests and stop.  So, we copy out
 482                                  * the ioc->last_waited time and test
 483                                  * against it before looping
 484                                  */
 485                                 last_waited = ioc->last_waited;
 486                                 cond_resched();
 487                                 continue;
 488                         }
 489                         spin_lock(&device->io_lock);
 490                         requeue_list(pending_bios, pending, tail);
 491                         device->running_pending = 1;
 492
 493                         spin_unlock(&device->io_lock);
 494                         btrfs_queue_work(fs_info->submit_workers,
 495                                          &device->work);
 496                         goto done;
 497                 }
 498                 /* unplug every 64 requests just for good measure */
 499                 if (batch_run % 64 == 0) {
 500                         blk_finish_plug(&plug);
 501                         blk_start_plug(&plug);
 502                         sync_pending = 0;
 503                 }
 504         }
 505
 506         cond_resched();
 507         if (again)
 508                 goto loop;
 509
 510         spin_lock(&device->io_lock);
 511         if (device->pending_bios.head || device->pending_sync_bios.head)
 512                 goto loop_lock;
 513         spin_unlock(&device->io_lock);
 514
 515 done:
 516         blk_finish_plug(&plug);
 517 }
 518
 519 static void pending_bios_fn(struct btrfs_work *work)
 520 {
 521         struct btrfs_device *device;
 522
 523         device = container_of(work, struct btrfs_device, work);
 524         run_scheduled_bios(device);
 525 }
 526
 527
 528 void btrfs_free_stale_device(struct btrfs_device *cur_dev)
 529 {
 530         struct btrfs_fs_devices *fs_devs;
 531         struct btrfs_device *dev;
 532
 533         if (!cur_dev->name)
 534                 return;
 535
 536         list_for_each_entry(fs_devs, &fs_uuids, list) {
 537                 int del = 1;
 538
 539                 if (fs_devs->opened)
 540                         continue;
 541                 if (fs_devs->seeding)
 542                         continue;
 543
 544                 list_for_each_entry(dev, &fs_devs->devices, dev_list) {
 545
 546                         if (dev == cur_dev)
 547                                 continue;
 548                         if (!dev->name)
 549                                 continue;
 550
 551                         /*
 552                          * Todo: This won't be enough. What if the same device
 553                          * comes back (with new uuid and) with its mapper path?
 554                          * But for now, this does help as mostly an admin will
 555                          * either use mapper or non mapper path throughout.
 556                          */
 557                         rcu_read_lock();
 558                         del = strcmp(rcu_str_deref(dev->name),
 559                                                 rcu_str_deref(cur_dev->name));
 560                         rcu_read_unlock();
 561                         if (!del)
 562                                 break;
 563                 }
 564
 565                 if (!del) {
 566                         /* delete the stale device */
 567                         if (fs_devs->num_devices == 1) {
 568                                 btrfs_sysfs_remove_fsid(fs_devs);
 569                                 list_del(&fs_devs->list);
 570                                 free_fs_devices(fs_devs);
 571                                 break;
 572                         } else {
 573                                 fs_devs->num_devices--;
 574                                 list_del(&dev->dev_list);
 575                                 rcu_string_free(dev->name);
 576                                 kfree(dev);
 577                         }
 578                         break;
 579                 }
 580         }
 581 }
 582
 583 /*
 584  * Add new device to list of registered devices
 585  *
 586  * Returns:
 587  * 1   - first time device is seen
 588  * 0   - device already known
 589  * < 0 - error
 590  */
 591 static noinline int device_list_add(const char *path,
 592                            struct btrfs_super_block *disk_super,
 593                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 594 {
 595         struct btrfs_device *device;
 596         struct btrfs_fs_devices *fs_devices;
 597         struct rcu_string *name;
 598         int ret = 0;
 599         u64 found_transid = btrfs_super_generation(disk_super);
 600
 601         fs_devices = find_fsid(disk_super->fsid);
 602         if (!fs_devices) {
 603                 fs_devices = alloc_fs_devices(disk_super->fsid);
 604                 if (IS_ERR(fs_devices))
 605                         return PTR_ERR(fs_devices);
 606
 607                 list_add(&fs_devices->list, &fs_uuids);
 608
 609                 device = NULL;
 610         } else {
 611                 device = __find_device(&fs_devices->devices, devid,
 612                                        disk_super->dev_item.uuid);
 613         }
 614
 615         if (!device) {
 616                 if (fs_devices->opened)
 617                         return -EBUSY;
 618
 619                 device = btrfs_alloc_device(NULL, &devid,
 620                                             disk_super->dev_item.uuid);
 621                 if (IS_ERR(device)) {
 622                         /* we can safely leave the fs_devices entry around */
 623                         return PTR_ERR(device);
 624                 }
 625
 626                 name = rcu_string_strdup(path, GFP_NOFS);
 627                 if (!name) {
 628                         kfree(device);
 629                         return -ENOMEM;
 630                 }
 631                 rcu_assign_pointer(device->name, name);
 632
 633                 mutex_lock(&fs_devices->device_list_mutex);
 634                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 635                 fs_devices->num_devices++;
 636                 mutex_unlock(&fs_devices->device_list_mutex);
 637
 638                 ret = 1;
 639                 device->fs_devices = fs_devices;
 640         } else if (!device->name || strcmp(device->name->str, path)) {
 641                 /*
 642                  * When FS is already mounted.
 643                  * 1. If you are here and if the device->name is NULL that
 644                  *    means this device was missing at time of FS mount.
 645                  * 2. If you are here and if the device->name is different
 646                  *    from 'path' that means either
 647                  *      a. The same device disappeared and reappeared with
 648                  *         different name. or
 649                  *      b. The missing-disk-which-was-replaced, has
 650                  *         reappeared now.
 651                  *
 652                  * We must allow 1 and 2a above. But 2b would be a spurious
 653                  * and unintentional.
 654                  *
 655                  * Further in case of 1 and 2a above, the disk at 'path'
 656                  * would have missed some transaction when it was away and
 657                  * in case of 2a the stale bdev has to be updated as well.
 658                  * 2b must not be allowed at all time.
 659                  */
 660
 661                 /*
 662                  * For now, we do allow update to btrfs_fs_device through the
 663                  * btrfs dev scan cli after FS has been mounted.  We're still
 664                  * tracking a problem where systems fail mount by subvolume id
 665                  * when we reject replacement on a mounted FS.
 666                  */
 667                 if (!fs_devices->opened && found_transid < device->generation) {
 668                         /*
 669                          * That is if the FS is _not_ mounted and if you
 670                          * are here, that means there is more than one
 671                          * disk with same uuid and devid.We keep the one
 672                          * with larger generation number or the last-in if
 673                          * generation are equal.
 674                          */
 675                         return -EEXIST;
 676                 }
 677
 678                 name = rcu_string_strdup(path, GFP_NOFS);
 679                 if (!name)
 680                         return -ENOMEM;
 681                 rcu_string_free(device->name);
 682                 rcu_assign_pointer(device->name, name);
 683                 if (device->missing) {
 684                         fs_devices->missing_devices--;
 685                         device->missing = 0;
 686                 }
 687         }
 688
 689         /*
 690          * Unmount does not free the btrfs_device struct but would zero
 691          * generation along with most of the other members. So just update
 692          * it back. We need it to pick the disk with largest generation
 693          * (as above).
 694          */
 695         if (!fs_devices->opened)
 696                 device->generation = found_transid;
 697
 698         /*
 699          * if there is new btrfs on an already registered device,
 700          * then remove the stale device entry.
 701          */
 702         btrfs_free_stale_device(device);
 703
 704         *fs_devices_ret = fs_devices;
 705
 706         return ret;
 707 }
 708
 709 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 710 {
 711         struct btrfs_fs_devices *fs_devices;
 712         struct btrfs_device *device;
 713         struct btrfs_device *orig_dev;
 714
 715         fs_devices = alloc_fs_devices(orig->fsid);
 716         if (IS_ERR(fs_devices))
 717                 return fs_devices;
 718
 719         mutex_lock(&orig->device_list_mutex);
 720         fs_devices->total_devices = orig->total_devices;
 721
 722         /* We have held the volume lock, it is safe to get the devices. */
 723         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 724                 struct rcu_string *name;
 725
 726                 device = btrfs_alloc_device(NULL, &orig_dev->devid,
 727                                             orig_dev->uuid);
 728                 if (IS_ERR(device))
 729                         goto error;
 730
 731                 /*
 732                  * This is ok to do without rcu read locked because we hold the
 733                  * uuid mutex so nothing we touch in here is going to disappear.
 734                  */
 735                 if (orig_dev->name) {
 736                         name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 737                         if (!name) {
 738                                 kfree(device);
 739                                 goto error;
 740                         }
 741                         rcu_assign_pointer(device->name, name);
 742                 }
 743
 744                 list_add(&device->dev_list, &fs_devices->devices);
 745                 device->fs_devices = fs_devices;
 746                 fs_devices->num_devices++;
 747         }
 748         mutex_unlock(&orig->device_list_mutex);
 749         return fs_devices;
 750 error:
 751         mutex_unlock(&orig->device_list_mutex);
 752         free_fs_devices(fs_devices);
 753         return ERR_PTR(-ENOMEM);
 754 }
 755
 756 void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices, int step)
 757 {
 758         struct btrfs_device *device, *next;
 759         struct btrfs_device *latest_dev = NULL;
 760
 761         mutex_lock(&uuid_mutex);
 762 again:
 763         /* This is the initialized path, it is safe to release the devices. */
 764         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 765                 if (device->in_fs_metadata) {
 766                         if (!device->is_tgtdev_for_dev_replace &&
 767                             (!latest_dev ||
 768                              device->generation > latest_dev->generation)) {
 769                                 latest_dev = device;
 770                         }
 771                         continue;
 772                 }
 773
 774                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 775                         /*
 776                          * In the first step, keep the device which has
 777                          * the correct fsid and the devid that is used
 778                          * for the dev_replace procedure.
 779                          * In the second step, the dev_replace state is
 780                          * read from the device tree and it is known
 781                          * whether the procedure is really active or
 782                          * not, which means whether this device is
 783                          * used or whether it should be removed.
 784                          */
 785                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 786                                 continue;
 787                         }
 788                 }
 789                 if (device->bdev) {
 790                         blkdev_put(device->bdev, device->mode);
 791                         device->bdev = NULL;
 792                         fs_devices->open_devices--;
 793                 }
 794                 if (device->writeable) {
 795                         list_del_init(&device->dev_alloc_list);
 796                         device->writeable = 0;
 797                         if (!device->is_tgtdev_for_dev_replace)
 798                                 fs_devices->rw_devices--;
 799                 }
 800                 list_del_init(&device->dev_list);
 801                 fs_devices->num_devices--;
 802                 rcu_string_free(device->name);
 803                 kfree(device);
 804         }
 805
 806         if (fs_devices->seed) {
 807                 fs_devices = fs_devices->seed;
 808                 goto again;
 809         }
 810
 811         fs_devices->latest_bdev = latest_dev->bdev;
 812
 813         mutex_unlock(&uuid_mutex);
 814 }
 815
 816 static void __free_device(struct work_struct *work)
 817 {
 818         struct btrfs_device *device;
 819
 820         device = container_of(work, struct btrfs_device, rcu_work);
 821
 822         if (device->bdev)
 823                 blkdev_put(device->bdev, device->mode);
 824
 825         rcu_string_free(device->name);
 826         kfree(device);
 827 }
 828
 829 static void free_device(struct rcu_head *head)
 830 {
 831         struct btrfs_device *device;
 832
 833         device = container_of(head, struct btrfs_device, rcu);
 834
 835         INIT_WORK(&device->rcu_work, __free_device);
 836         schedule_work(&device->rcu_work);
 837 }
 838
 839 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 840 {
 841         struct btrfs_device *device, *tmp;
 842
 843         if (--fs_devices->opened > 0)
 844                 return 0;
 845
 846         mutex_lock(&fs_devices->device_list_mutex);
 847         list_for_each_entry_safe(device, tmp, &fs_devices->devices, dev_list) {
 848                 btrfs_close_one_device(device);
 849         }
 850         mutex_unlock(&fs_devices->device_list_mutex);
 851
 852         WARN_ON(fs_devices->open_devices);
 853         WARN_ON(fs_devices->rw_devices);
 854         fs_devices->opened = 0;
 855         fs_devices->seeding = 0;
 856
 857         return 0;
 858 }
 859
 860 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 861 {
 862         struct btrfs_fs_devices *seed_devices = NULL;
 863         int ret;
 864
 865         mutex_lock(&uuid_mutex);
 866         ret = __btrfs_close_devices(fs_devices);
 867         if (!fs_devices->opened) {
 868                 seed_devices = fs_devices->seed;
 869                 fs_devices->seed = NULL;
 870         }
 871         mutex_unlock(&uuid_mutex);
 872
 873         while (seed_devices) {
 874                 fs_devices = seed_devices;
 875                 seed_devices = fs_devices->seed;
 876                 __btrfs_close_devices(fs_devices);
 877                 free_fs_devices(fs_devices);
 878         }
 879         /*
 880          * Wait for rcu kworkers under __btrfs_close_devices
 881          * to finish all blkdev_puts so device is really
 882          * free when umount is done.
 883          */
 884         rcu_barrier();
 885         return ret;
 886 }
 887
 888 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 889                                 fmode_t flags, void *holder)
 890 {
 891         struct request_queue *q;
 892         struct block_device *bdev;
 893         struct list_head *head = &fs_devices->devices;
 894         struct btrfs_device *device;
 895         struct btrfs_device *latest_dev = NULL;
 896         struct buffer_head *bh;
 897         struct btrfs_super_block *disk_super;
 898         u64 devid;
 899         int seeding = 1;
 900         int ret = 0;
 901
 902         flags |= FMODE_EXCL;
 903
 904         list_for_each_entry(device, head, dev_list) {
 905                 if (device->bdev)
 906                         continue;
 907                 if (!device->name)
 908                         continue;
 909
 910                 /* Just open everything we can; ignore failures here */
 911                 if (btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 912                                             &bdev, &bh))
 913                         continue;
 914
 915                 disk_super = (struct btrfs_super_block *)bh->b_data;
 916                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 917                 if (devid != device->devid)
 918                         goto error_brelse;
 919
 920                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 921                            BTRFS_UUID_SIZE))
 922                         goto error_brelse;
 923
 924                 device->generation = btrfs_super_generation(disk_super);
 925                 if (!latest_dev ||
 926                     device->generation > latest_dev->generation)
 927                         latest_dev = device;
 928
 929                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 930                         device->writeable = 0;
 931                 } else {
 932                         device->writeable = !bdev_read_only(bdev);
 933                         seeding = 0;
 934                 }
 935
 936                 q = bdev_get_queue(bdev);
 937                 if (blk_queue_discard(q))
 938                         device->can_discard = 1;
 939
 940                 device->bdev = bdev;
 941                 device->in_fs_metadata = 0;
 942                 device->mode = flags;
 943
 944                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 945                         fs_devices->rotating = 1;
 946
 947                 fs_devices->open_devices++;
 948                 if (device->writeable &&
 949                     device->devid != BTRFS_DEV_REPLACE_DEVID) {
 950                         fs_devices->rw_devices++;
 951                         list_add(&device->dev_alloc_list,
 952                                  &fs_devices->alloc_list);
 953                 }
 954                 brelse(bh);
 955                 continue;
 956
 957 error_brelse:
 958                 brelse(bh);
 959                 blkdev_put(bdev, flags);
 960                 continue;
 961         }
 962         if (fs_devices->open_devices == 0) {
 963                 ret = -EINVAL;
 964                 goto out;
 965         }
 966         fs_devices->seeding = seeding;
 967         fs_devices->opened = 1;
 968         fs_devices->latest_bdev = latest_dev->bdev;
 969         fs_devices->total_rw_bytes = 0;
 970 out:
 971         return ret;
 972 }
 973
 974 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 975                        fmode_t flags, void *holder)
 976 {
 977         int ret;
 978
 979         mutex_lock(&uuid_mutex);
 980         if (fs_devices->opened) {
 981                 fs_devices->opened++;
 982                 ret = 0;
 983         } else {
 984                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 985         }
 986         mutex_unlock(&uuid_mutex);
 987         return ret;
 988 }
 989
 990 /*
 991  * Look for a btrfs signature on a device. This may be called out of the mount path
 992  * and we are not allowed to call set_blocksize during the scan. The superblock
 993  * is read via pagecache
 994  */
 995 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 996                           struct btrfs_fs_devices **fs_devices_ret)
 997 {
 998         struct btrfs_super_block *disk_super;
 999         struct block_device *bdev;
1000         struct page *page;
1001         void *p;
1002         int ret = -EINVAL;
1003         u64 devid;
1004         u64 transid;
1005         u64 total_devices;
1006         u64 bytenr;
1007         pgoff_t index;
1008
1009         /*
1010          * we would like to check all the supers, but that would make
1011          * a btrfs mount succeed after a mkfs from a different FS.
1012          * So, we need to add a special mount option to scan for
1013          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
1014          */
1015         bytenr = btrfs_sb_offset(0);
1016         flags |= FMODE_EXCL;
1017         mutex_lock(&uuid_mutex);
1018
1019         bdev = blkdev_get_by_path(path, flags, holder);
1020
1021         if (IS_ERR(bdev)) {
1022                 ret = PTR_ERR(bdev);
1023                 goto error;
1024         }
1025
1026         /* make sure our super fits in the device */
1027         if (bytenr + PAGE_CACHE_SIZE >= i_size_read(bdev->bd_inode))
1028                 goto error_bdev_put;
1029
1030         /* make sure our super fits in the page */
1031         if (sizeof(*disk_super) > PAGE_CACHE_SIZE)
1032                 goto error_bdev_put;
1033
1034         /* make sure our super doesn't straddle pages on disk */
1035         index = bytenr >> PAGE_CACHE_SHIFT;
1036         if ((bytenr + sizeof(*disk_super) - 1) >> PAGE_CACHE_SHIFT != index)
1037                 goto error_bdev_put;
1038
1039         /* pull in the page with our super */
1040         page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
1041                                    index, GFP_NOFS);
1042
1043         if (IS_ERR_OR_NULL(page))
1044                 goto error_bdev_put;
1045
1046         p = kmap(page);
1047
1048         /* align our pointer to the offset of the super block */
1049         disk_super = p + (bytenr & ~PAGE_CACHE_MASK);
1050
1051         if (btrfs_super_bytenr(disk_super) != bytenr ||
1052             btrfs_super_magic(disk_super) != BTRFS_MAGIC)
1053                 goto error_unmap;
1054
1055         devid = btrfs_stack_device_id(&disk_super->dev_item);
1056         transid = btrfs_super_generation(disk_super);
1057         total_devices = btrfs_super_num_devices(disk_super);
1058
1059         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
1060         if (ret > 0) {
1061                 if (disk_super->label[0]) {
1062                         if (disk_super->label[BTRFS_LABEL_SIZE - 1])
1063                                 disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
1064                         printk(KERN_INFO "BTRFS: device label %s ", disk_super->label);
1065                 } else {
1066                         printk(KERN_INFO "BTRFS: device fsid %pU ", disk_super->fsid);
1067                 }
1068
1069                 printk(KERN_CONT "devid %llu transid %llu %s\n", devid, transid, path);
1070                 ret = 0;
1071         }
1072         if (!ret && fs_devices_ret)
1073                 (*fs_devices_ret)->total_devices = total_devices;
1074
1075 error_unmap:
1076         kunmap(page);
1077         page_cache_release(page);
1078
1079 error_bdev_put:
1080         blkdev_put(bdev, flags);
1081 error:
1082         mutex_unlock(&uuid_mutex);
1083         return ret;
1084 }
1085
1086 /* helper to account the used device space in the range */
1087 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
1088                                    u64 end, u64 *length)
1089 {
1090         struct btrfs_key key;
1091         struct btrfs_root *root = device->dev_root;
1092         struct btrfs_dev_extent *dev_extent;
1093         struct btrfs_path *path;
1094         u64 extent_end;
1095         int ret;
1096         int slot;
1097         struct extent_buffer *l;
1098
1099         *length = 0;
1100
1101         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
1102                 return 0;
1103
1104         path = btrfs_alloc_path();
1105         if (!path)
1106                 return -ENOMEM;
1107         path->reada = 2;
1108
1109         key.objectid = device->devid;
1110         key.offset = start;
1111         key.type = BTRFS_DEV_EXTENT_KEY;
1112
1113         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1114         if (ret < 0)
1115                 goto out;
1116         if (ret > 0) {
1117                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1118                 if (ret < 0)
1119                         goto out;
1120         }
1121
1122         while (1) {
1123                 l = path->nodes[0];
1124                 slot = path->slots[0];
1125                 if (slot >= btrfs_header_nritems(l)) {
1126                         ret = btrfs_next_leaf(root, path);
1127                         if (ret == 0)
1128                                 continue;
1129                         if (ret < 0)
1130                                 goto out;
1131
1132                         break;
1133                 }
1134                 btrfs_item_key_to_cpu(l, &key, slot);
1135
1136                 if (key.objectid < device->devid)
1137                         goto next;
1138
1139                 if (key.objectid > device->devid)
1140                         break;
1141
1142                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1143                         goto next;
1144
1145                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1146                 extent_end = key.offset + btrfs_dev_extent_length(l,
1147                                                                   dev_extent);
1148                 if (key.offset <= start && extent_end > end) {
1149                         *length = end - start + 1;
1150                         break;
1151                 } else if (key.offset <= start && extent_end > start)
1152                         *length += extent_end - start;
1153                 else if (key.offset > start && extent_end <= end)
1154                         *length += extent_end - key.offset;
1155                 else if (key.offset > start && key.offset <= end) {
1156                         *length += end - key.offset + 1;
1157                         break;
1158                 } else if (key.offset > end)
1159                         break;
1160
1161 next:
1162                 path->slots[0]++;
1163         }
1164         ret = 0;
1165 out:
1166         btrfs_free_path(path);
1167         return ret;
1168 }
1169
1170 static int contains_pending_extent(struct btrfs_transaction *transaction,
1171                                    struct btrfs_device *device,
1172                                    u64 *start, u64 len)
1173 {
1174         struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
1175         struct extent_map *em;
1176         struct list_head *search_list = &fs_info->pinned_chunks;
1177         int ret = 0;
1178         u64 physical_start = *start;
1179
1180         if (transaction)
1181                 search_list = &transaction->pending_chunks;
1182 again:
1183         list_for_each_entry(em, search_list, list) {
1184                 struct map_lookup *map;
1185                 int i;
1186
1187                 map = em->map_lookup;
1188                 for (i = 0; i < map->num_stripes; i++) {
1189                         u64 end;
1190
1191                         if (map->stripes[i].dev != device)
1192                                 continue;
1193                         if (map->stripes[i].physical >= physical_start + len ||
1194                             map->stripes[i].physical + em->orig_block_len <=
1195                             physical_start)
1196                                 continue;
1197                         /*
1198                          * Make sure that while processing the pinned list we do
1199                          * not override our *start with a lower value, because
1200                          * we can have pinned chunks that fall within this
1201                          * device hole and that have lower physical addresses
1202                          * than the pending chunks we processed before. If we
1203                          * do not take this special care we can end up getting
1204                          * 2 pending chunks that start at the same physical
1205                          * device offsets because the end offset of a pinned
1206                          * chunk can be equal to the start offset of some
1207                          * pending chunk.
1208                          */
1209                         end = map->stripes[i].physical + em->orig_block_len;
1210                         if (end > *start) {
1211                                 *start = end;
1212                                 ret = 1;
1213                         }
1214                 }
1215         }
1216         if (search_list != &fs_info->pinned_chunks) {
1217                 search_list = &fs_info->pinned_chunks;
1218                 goto again;
1219         }
1220
1221         return ret;
1222 }
1223
1224
1225 /*
1226  * find_free_dev_extent_start - find free space in the specified device
1227  * @device:       the device which we search the free space in
1228  * @num_bytes:    the size of the free space that we need
1229  * @search_start: the position from which to begin the search
1230  * @start:        store the start of the free space.
1231  * @len:          the size of the free space. that we find, or the size
1232  *                of the max free space if we don't find suitable free space
1233  *
1234  * this uses a pretty simple search, the expectation is that it is
1235  * called very infrequently and that a given device has a small number
1236  * of extents
1237  *
1238  * @start is used to store the start of the free space if we find. But if we
1239  * don't find suitable free space, it will be used to store the start position
1240  * of the max free space.
1241  *
1242  * @len is used to store the size of the free space that we find.
1243  * But if we don't find suitable free space, it is used to store the size of
1244  * the max free space.
1245  */
1246 int find_free_dev_extent_start(struct btrfs_transaction *transaction,
1247                                struct btrfs_device *device, u64 num_bytes,
1248                                u64 search_start, u64 *start, u64 *len)
1249 {
1250         struct btrfs_key key;
1251         struct btrfs_root *root = device->dev_root;
1252         struct btrfs_dev_extent *dev_extent;
1253         struct btrfs_path *path;
1254         u64 hole_size;
1255         u64 max_hole_start;
1256         u64 max_hole_size;
1257         u64 extent_end;
1258         u64 search_end = device->total_bytes;
1259         int ret;
1260         int slot;
1261         struct extent_buffer *l;
1262         u64 min_search_start;
1263
1264         /*
1265          * We don't want to overwrite the superblock on the drive nor any area
1266          * used by the boot loader (grub for example), so we make sure to start
1267          * at an offset of at least 1MB.
1268          */
1269         min_search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
1270         search_start = max(search_start, min_search_start);
1271
1272         path = btrfs_alloc_path();
1273         if (!path)
1274                 return -ENOMEM;
1275
1276         max_hole_start = search_start;
1277         max_hole_size = 0;
1278
1279 again:
1280         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
1281                 ret = -ENOSPC;
1282                 goto out;
1283         }
1284
1285         path->reada = 2;
1286         path->search_commit_root = 1;
1287         path->skip_locking = 1;
1288
1289         key.objectid = device->devid;
1290         key.offset = search_start;
1291         key.type = BTRFS_DEV_EXTENT_KEY;
1292
1293         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1294         if (ret < 0)
1295                 goto out;
1296         if (ret > 0) {
1297                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1298                 if (ret < 0)
1299                         goto out;
1300         }
1301
1302         while (1) {
1303                 l = path->nodes[0];
1304                 slot = path->slots[0];
1305                 if (slot >= btrfs_header_nritems(l)) {
1306                         ret = btrfs_next_leaf(root, path);
1307                         if (ret == 0)
1308                                 continue;
1309                         if (ret < 0)
1310                                 goto out;
1311
1312                         break;
1313                 }
1314                 btrfs_item_key_to_cpu(l, &key, slot);
1315
1316                 if (key.objectid < device->devid)
1317                         goto next;
1318
1319                 if (key.objectid > device->devid)
1320                         break;
1321
1322                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1323                         goto next;
1324
1325                 if (key.offset > search_start) {
1326                         hole_size = key.offset - search_start;
1327
1328                         /*
1329                          * Have to check before we set max_hole_start, otherwise
1330                          * we could end up sending back this offset anyway.
1331                          */
1332                         if (contains_pending_extent(transaction, device,
1333                                                     &search_start,
1334                                                     hole_size)) {
1335                                 if (key.offset >= search_start) {
1336                                         hole_size = key.offset - search_start;
1337                                 } else {
1338                                         WARN_ON_ONCE(1);
1339                                         hole_size = 0;
1340                                 }
1341                         }
1342
1343                         if (hole_size > max_hole_size) {
1344                                 max_hole_start = search_start;
1345                                 max_hole_size = hole_size;
1346                         }
1347
1348                         /*
1349                          * If this free space is greater than which we need,
1350                          * it must be the max free space that we have found
1351                          * until now, so max_hole_start must point to the start
1352                          * of this free space and the length of this free space
1353                          * is stored in max_hole_size. Thus, we return
1354                          * max_hole_start and max_hole_size and go back to the
1355                          * caller.
1356                          */
1357                         if (hole_size >= num_bytes) {
1358                                 ret = 0;
1359                                 goto out;
1360                         }
1361                 }
1362
1363                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1364                 extent_end = key.offset + btrfs_dev_extent_length(l,
1365                                                                   dev_extent);
1366                 if (extent_end > search_start)
1367                         search_start = extent_end;
1368 next:
1369                 path->slots[0]++;
1370                 cond_resched();
1371         }
1372
1373         /*
1374          * At this point, search_start should be the end of
1375          * allocated dev extents, and when shrinking the device,
1376          * search_end may be smaller than search_start.
1377          */
1378         if (search_end > search_start) {
1379                 hole_size = search_end - search_start;
1380
1381                 if (contains_pending_extent(transaction, device, &search_start,
1382                                             hole_size)) {
1383                         btrfs_release_path(path);
1384                         goto again;
1385                 }
1386
1387                 if (hole_size > max_hole_size) {
1388                         max_hole_start = search_start;
1389                         max_hole_size = hole_size;
1390                 }
1391         }
1392
1393         /* See above. */
1394         if (max_hole_size < num_bytes)
1395                 ret = -ENOSPC;
1396         else
1397                 ret = 0;
1398
1399 out:
1400         btrfs_free_path(path);
1401         *start = max_hole_start;
1402         if (len)
1403                 *len = max_hole_size;
1404         return ret;
1405 }
1406
1407 int find_free_dev_extent(struct btrfs_trans_handle *trans,
1408                          struct btrfs_device *device, u64 num_bytes,
1409                          u64 *start, u64 *len)
1410 {
1411         /* FIXME use last free of some kind */
1412         return find_free_dev_extent_start(trans->transaction, device,
1413                                           num_bytes, 0, start, len);
1414 }
1415
1416 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1417                           struct btrfs_device *device,
1418                           u64 start, u64 *dev_extent_len)
1419 {
1420         int ret;
1421         struct btrfs_path *path;
1422         struct btrfs_root *root = device->dev_root;
1423         struct btrfs_key key;
1424         struct btrfs_key found_key;
1425         struct extent_buffer *leaf = NULL;
1426         struct btrfs_dev_extent *extent = NULL;
1427
1428         path = btrfs_alloc_path();
1429         if (!path)
1430                 return -ENOMEM;
1431
1432         key.objectid = device->devid;
1433         key.offset = start;
1434         key.type = BTRFS_DEV_EXTENT_KEY;
1435 again:
1436         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1437         if (ret > 0) {
1438                 ret = btrfs_previous_item(root, path, key.objectid,
1439                                           BTRFS_DEV_EXTENT_KEY);
1440                 if (ret)
1441                         goto out;
1442                 leaf = path->nodes[0];
1443                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1444                 extent = btrfs_item_ptr(leaf, path->slots[0],
1445                                         struct btrfs_dev_extent);
1446                 BUG_ON(found_key.offset > start || found_key.offset +
1447                        btrfs_dev_extent_length(leaf, extent) < start);
1448                 key = found_key;
1449                 btrfs_release_path(path);
1450                 goto again;
1451         } else if (ret == 0) {
1452                 leaf = path->nodes[0];
1453                 extent = btrfs_item_ptr(leaf, path->slots[0],
1454                                         struct btrfs_dev_extent);
1455         } else {
1456                 btrfs_std_error(root->fs_info, ret, "Slot search failed");
1457                 goto out;
1458         }
1459
1460         *dev_extent_len = btrfs_dev_extent_length(leaf, extent);
1461
1462         ret = btrfs_del_item(trans, root, path);
1463         if (ret) {
1464                 btrfs_std_error(root->fs_info, ret,
1465                             "Failed to remove dev extent item");
1466         } else {
1467                 set_bit(BTRFS_TRANS_HAVE_FREE_BGS, &trans->transaction->flags);
1468         }
1469 out:
1470         btrfs_free_path(path);
1471         return ret;
1472 }
1473
1474 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1475                                   struct btrfs_device *device,
1476                                   u64 chunk_tree, u64 chunk_objectid,
1477                                   u64 chunk_offset, u64 start, u64 num_bytes)
1478 {
1479         int ret;
1480         struct btrfs_path *path;
1481         struct btrfs_root *root = device->dev_root;
1482         struct btrfs_dev_extent *extent;
1483         struct extent_buffer *leaf;
1484         struct btrfs_key key;
1485
1486         WARN_ON(!device->in_fs_metadata);
1487         WARN_ON(device->is_tgtdev_for_dev_replace);
1488         path = btrfs_alloc_path();
1489         if (!path)
1490                 return -ENOMEM;
1491
1492         key.objectid = device->devid;
1493         key.offset = start;
1494         key.type = BTRFS_DEV_EXTENT_KEY;
1495         ret = btrfs_insert_empty_item(trans, root, path, &key,
1496                                       sizeof(*extent));
1497         if (ret)
1498                 goto out;
1499
1500         leaf = path->nodes[0];
1501         extent = btrfs_item_ptr(leaf, path->slots[0],
1502                                 struct btrfs_dev_extent);
1503         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1504         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1505         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1506
1507         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1508                     btrfs_dev_extent_chunk_tree_uuid(extent), BTRFS_UUID_SIZE);
1509
1510         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1511         btrfs_mark_buffer_dirty(leaf);
1512 out:
1513         btrfs_free_path(path);
1514         return ret;
1515 }
1516
1517 static u64 find_next_chunk(struct btrfs_fs_info *fs_info)
1518 {
1519         struct extent_map_tree *em_tree;
1520         struct extent_map *em;
1521         struct rb_node *n;
1522         u64 ret = 0;
1523
1524         em_tree = &fs_info->mapping_tree.map_tree;
1525         read_lock(&em_tree->lock);
1526         n = rb_last(&em_tree->map);
1527         if (n) {
1528                 em = rb_entry(n, struct extent_map, rb_node);
1529                 ret = em->start + em->len;
1530         }
1531         read_unlock(&em_tree->lock);
1532
1533         return ret;
1534 }
1535
1536 static noinline int find_next_devid(struct btrfs_fs_info *fs_info,
1537                                     u64 *devid_ret)
1538 {
1539         int ret;
1540         struct btrfs_key key;
1541         struct btrfs_key found_key;
1542         struct btrfs_path *path;
1543
1544         path = btrfs_alloc_path();
1545         if (!path)
1546                 return -ENOMEM;
1547
1548         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1549         key.type = BTRFS_DEV_ITEM_KEY;
1550         key.offset = (u64)-1;
1551
1552         ret = btrfs_search_slot(NULL, fs_info->chunk_root, &key, path, 0, 0);
1553         if (ret < 0)
1554                 goto error;
1555
1556         BUG_ON(ret == 0); /* Corruption */
1557
1558         ret = btrfs_previous_item(fs_info->chunk_root, path,
1559                                   BTRFS_DEV_ITEMS_OBJECTID,
1560                                   BTRFS_DEV_ITEM_KEY);
1561         if (ret) {
1562                 *devid_ret = 1;
1563         } else {
1564                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1565                                       path->slots[0]);
1566                 *devid_ret = found_key.offset + 1;
1567         }
1568         ret = 0;
1569 error:
1570         btrfs_free_path(path);
1571         return ret;
1572 }
1573
1574 /*
1575  * the device information is stored in the chunk root
1576  * the btrfs_device struct should be fully filled in
1577  */
1578 static int btrfs_add_device(struct btrfs_trans_handle *trans,
1579                             struct btrfs_root *root,
1580                             struct btrfs_device *device)
1581 {
1582         int ret;
1583         struct btrfs_path *path;
1584         struct btrfs_dev_item *dev_item;
1585         struct extent_buffer *leaf;
1586         struct btrfs_key key;
1587         unsigned long ptr;
1588
1589         root = root->fs_info->chunk_root;
1590
1591         path = btrfs_alloc_path();
1592         if (!path)
1593                 return -ENOMEM;
1594
1595         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1596         key.type = BTRFS_DEV_ITEM_KEY;
1597         key.offset = device->devid;
1598
1599         ret = btrfs_insert_empty_item(trans, root, path, &key,
1600                                       sizeof(*dev_item));
1601         if (ret)
1602                 goto out;
1603
1604         leaf = path->nodes[0];
1605         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1606
1607         btrfs_set_device_id(leaf, dev_item, device->devid);
1608         btrfs_set_device_generation(leaf, dev_item, 0);
1609         btrfs_set_device_type(leaf, dev_item, device->type);
1610         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1611         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1612         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1613         btrfs_set_device_total_bytes(leaf, dev_item,
1614                                      btrfs_device_get_disk_total_bytes(device));
1615         btrfs_set_device_bytes_used(leaf, dev_item,
1616                                     btrfs_device_get_bytes_used(device));
1617         btrfs_set_device_group(leaf, dev_item, 0);
1618         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1619         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1620         btrfs_set_device_start_offset(leaf, dev_item, 0);
1621
1622         ptr = btrfs_device_uuid(dev_item);
1623         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1624         ptr = btrfs_device_fsid(dev_item);
1625         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1626         btrfs_mark_buffer_dirty(leaf);
1627
1628         ret = 0;
1629 out:
1630         btrfs_free_path(path);
1631         return ret;
1632 }
1633
1634 /*
1635  * Function to update ctime/mtime for a given device path.
1636  * Mainly used for ctime/mtime based probe like libblkid.
1637  */
1638 static void update_dev_time(char *path_name)
1639 {
1640         struct file *filp;
1641
1642         filp = filp_open(path_name, O_RDWR, 0);
1643         if (IS_ERR(filp))
1644                 return;
1645         file_update_time(filp);
1646         filp_close(filp, NULL);
1647         return;
1648 }
1649
1650 static int btrfs_rm_dev_item(struct btrfs_root *root,
1651                              struct btrfs_device *device)
1652 {
1653         int ret;
1654         struct btrfs_path *path;
1655         struct btrfs_key key;
1656         struct btrfs_trans_handle *trans;
1657
1658         root = root->fs_info->chunk_root;
1659
1660         path = btrfs_alloc_path();
1661         if (!path)
1662                 return -ENOMEM;
1663
1664         trans = btrfs_start_transaction(root, 0);
1665         if (IS_ERR(trans)) {
1666                 btrfs_free_path(path);
1667                 return PTR_ERR(trans);
1668         }
1669         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1670         key.type = BTRFS_DEV_ITEM_KEY;
1671         key.offset = device->devid;
1672
1673         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1674         if (ret < 0)
1675                 goto out;
1676
1677         if (ret > 0) {
1678                 ret = -ENOENT;
1679                 goto out;
1680         }
1681
1682         ret = btrfs_del_item(trans, root, path);
1683         if (ret)
1684                 goto out;
1685 out:
1686         btrfs_free_path(path);
1687         btrfs_commit_transaction(trans, root);
1688         return ret;
1689 }
1690
1691 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1692 {
1693         struct btrfs_device *device;
1694         struct btrfs_device *next_device;
1695         struct block_device *bdev;
1696         struct buffer_head *bh = NULL;
1697         struct btrfs_super_block *disk_super;
1698         struct btrfs_fs_devices *cur_devices;
1699         u64 all_avail;
1700         u64 devid;
1701         u64 num_devices;
1702         u8 *dev_uuid;
1703         unsigned seq;
1704         int ret = 0;
1705         bool clear_super = false;
1706
1707         mutex_lock(&uuid_mutex);
1708
1709         do {
1710                 seq = read_seqbegin(&root->fs_info->profiles_lock);
1711
1712                 all_avail = root->fs_info->avail_data_alloc_bits |
1713                             root->fs_info->avail_system_alloc_bits |
1714                             root->fs_info->avail_metadata_alloc_bits;
1715         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
1716
1717         num_devices = root->fs_info->fs_devices->num_devices;
1718         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1719         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1720                 WARN_ON(num_devices < 1);
1721                 num_devices--;
1722         }
1723         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1724
1725         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1726                 ret = BTRFS_ERROR_DEV_RAID10_MIN_NOT_MET;
1727                 goto out;
1728         }
1729
1730         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1731                 ret = BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET;
1732                 goto out;
1733         }
1734
1735         if ((all_avail & BTRFS_BLOCK_GROUP_RAID5) &&
1736             root->fs_info->fs_devices->rw_devices <= 2) {
1737                 ret = BTRFS_ERROR_DEV_RAID5_MIN_NOT_MET;
1738                 goto out;
1739         }
1740         if ((all_avail & BTRFS_BLOCK_GROUP_RAID6) &&
1741             root->fs_info->fs_devices->rw_devices <= 3) {
1742                 ret = BTRFS_ERROR_DEV_RAID6_MIN_NOT_MET;
1743                 goto out;
1744         }
1745
1746         if (strcmp(device_path, "missing") == 0) {
1747                 struct list_head *devices;
1748                 struct btrfs_device *tmp;
1749
1750                 device = NULL;
1751                 devices = &root->fs_info->fs_devices->devices;
1752                 /*
1753                  * It is safe to read the devices since the volume_mutex
1754                  * is held.
1755                  */
1756                 list_for_each_entry(tmp, devices, dev_list) {
1757                         if (tmp->in_fs_metadata &&
1758                             !tmp->is_tgtdev_for_dev_replace &&
1759                             !tmp->bdev) {
1760                                 device = tmp;
1761                                 break;
1762                         }
1763                 }
1764                 bdev = NULL;
1765                 bh = NULL;
1766                 disk_super = NULL;
1767                 if (!device) {
1768                         ret = BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
1769                         goto out;
1770                 }
1771         } else {
1772                 ret = btrfs_get_bdev_and_sb(device_path,
1773                                             FMODE_WRITE | FMODE_EXCL,
1774                                             root->fs_info->bdev_holder, 0,
1775                                             &bdev, &bh);
1776                 if (ret)
1777                         goto out;
1778                 disk_super = (struct btrfs_super_block *)bh->b_data;
1779                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1780                 dev_uuid = disk_super->dev_item.uuid;
1781                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1782                                            disk_super->fsid);
1783                 if (!device) {
1784                         ret = -ENOENT;
1785                         goto error_brelse;
1786                 }
1787         }
1788
1789         if (device->is_tgtdev_for_dev_replace) {
1790                 ret = BTRFS_ERROR_DEV_TGT_REPLACE;
1791                 goto error_brelse;
1792         }
1793
1794         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1795                 ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
1796                 goto error_brelse;
1797         }
1798
1799         if (device->writeable) {
1800                 lock_chunks(root);
1801                 list_del_init(&device->dev_alloc_list);
1802                 device->fs_devices->rw_devices--;
1803                 unlock_chunks(root);
1804                 clear_super = true;
1805         }
1806
1807         mutex_unlock(&uuid_mutex);
1808         ret = btrfs_shrink_device(device, 0);
1809         mutex_lock(&uuid_mutex);
1810         if (ret)
1811                 goto error_undo;
1812
1813         /*
1814          * TODO: the superblock still includes this device in its num_devices
1815          * counter although write_all_supers() is not locked out. This
1816          * could give a filesystem state which requires a degraded mount.
1817          */
1818         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1819         if (ret)
1820                 goto error_undo;
1821
1822         device->in_fs_metadata = 0;
1823         btrfs_scrub_cancel_dev(root->fs_info, device);
1824
1825         /*
1826          * the device list mutex makes sure that we don't change
1827          * the device list while someone else is writing out all
1828          * the device supers. Whoever is writing all supers, should
1829          * lock the device list mutex before getting the number of
1830          * devices in the super block (super_copy). Conversely,
1831          * whoever updates the number of devices in the super block
1832          * (super_copy) should hold the device list mutex.
1833          */
1834
1835         cur_devices = device->fs_devices;
1836         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1837         list_del_rcu(&device->dev_list);
1838
1839         device->fs_devices->num_devices--;
1840         device->fs_devices->total_devices--;
1841
1842         if (device->missing)
1843                 device->fs_devices->missing_devices--;
1844
1845         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1846                                  struct btrfs_device, dev_list);
1847         if (device->bdev == root->fs_info->sb->s_bdev)
1848                 root->fs_info->sb->s_bdev = next_device->bdev;
1849         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1850                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1851
1852         if (device->bdev) {
1853                 device->fs_devices->open_devices--;
1854                 /* remove sysfs entry */
1855                 btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
1856         }
1857
1858         call_rcu(&device->rcu, free_device);
1859
1860         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1861         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1862         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1863
1864         if (cur_devices->open_devices == 0) {
1865                 struct btrfs_fs_devices *fs_devices;
1866                 fs_devices = root->fs_info->fs_devices;
1867                 while (fs_devices) {
1868                         if (fs_devices->seed == cur_devices) {
1869                                 fs_devices->seed = cur_devices->seed;
1870                                 break;
1871                         }
1872                         fs_devices = fs_devices->seed;
1873                 }
1874                 cur_devices->seed = NULL;
1875                 __btrfs_close_devices(cur_devices);
1876                 free_fs_devices(cur_devices);
1877         }
1878
1879         root->fs_info->num_tolerated_disk_barrier_failures =
1880                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1881
1882         /*
1883          * at this point, the device is zero sized.  We want to
1884          * remove it from the devices list and zero out the old super
1885          */
1886         if (clear_super && disk_super) {
1887                 u64 bytenr;
1888                 int i;
1889
1890                 /* make sure this device isn't detected as part of
1891                  * the FS anymore
1892                  */
1893                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1894                 set_buffer_dirty(bh);
1895                 sync_dirty_buffer(bh);
1896
1897                 /* clear the mirror copies of super block on the disk
1898                  * being removed, 0th copy is been taken care above and
1899                  * the below would take of the rest
1900                  */
1901                 for (i = 1; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1902                         bytenr = btrfs_sb_offset(i);
1903                         if (bytenr + BTRFS_SUPER_INFO_SIZE >=
1904                                         i_size_read(bdev->bd_inode))
1905                                 break;
1906
1907                         brelse(bh);
1908                         bh = __bread(bdev, bytenr / 4096,
1909                                         BTRFS_SUPER_INFO_SIZE);
1910                         if (!bh)
1911                                 continue;
1912
1913                         disk_super = (struct btrfs_super_block *)bh->b_data;
1914
1915                         if (btrfs_super_bytenr(disk_super) != bytenr ||
1916                                 btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
1917                                 continue;
1918                         }
1919                         memset(&disk_super->magic, 0,
1920                                                 sizeof(disk_super->magic));
1921                         set_buffer_dirty(bh);
1922                         sync_dirty_buffer(bh);
1923                 }
1924         }
1925
1926         ret = 0;
1927
1928         if (bdev) {
1929                 /* Notify udev that device has changed */
1930                 btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1931
1932                 /* Update ctime/mtime for device path for libblkid */
1933                 update_dev_time(device_path);
1934         }
1935
1936 error_brelse:
1937         brelse(bh);
1938         if (bdev)
1939                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1940 out:
1941         mutex_unlock(&uuid_mutex);
1942         return ret;
1943 error_undo:
1944         if (device->writeable) {
1945                 lock_chunks(root);
1946                 list_add(&device->dev_alloc_list,
1947                          &root->fs_info->fs_devices->alloc_list);
1948                 device->fs_devices->rw_devices++;
1949                 unlock_chunks(root);
1950         }
1951         goto error_brelse;
1952 }
1953
1954 void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,
1955                                         struct btrfs_device *srcdev)
1956 {
1957         struct btrfs_fs_devices *fs_devices;
1958
1959         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1960
1961         /*
1962          * in case of fs with no seed, srcdev->fs_devices will point
1963          * to fs_devices of fs_info. However when the dev being replaced is
1964          * a seed dev it will point to the seed's local fs_devices. In short
1965          * srcdev will have its correct fs_devices in both the cases.
1966          */
1967         fs_devices = srcdev->fs_devices;
1968
1969         list_del_rcu(&srcdev->dev_list);
1970         list_del_rcu(&srcdev->dev_alloc_list);
1971         fs_devices->num_devices--;
1972         if (srcdev->missing)
1973                 fs_devices->missing_devices--;
1974
1975         if (srcdev->writeable) {
1976                 fs_devices->rw_devices--;
1977                 /* zero out the old super if it is writable */
1978                 btrfs_scratch_superblocks(srcdev->bdev, srcdev->name->str);
1979         }
1980
1981         if (srcdev->bdev)
1982                 fs_devices->open_devices--;
1983 }
1984
1985 void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info,
1986                                       struct btrfs_device *srcdev)
1987 {
1988         struct btrfs_fs_devices *fs_devices = srcdev->fs_devices;
1989
1990         call_rcu(&srcdev->rcu, free_device);
1991
1992         /*
1993          * unless fs_devices is seed fs, num_devices shouldn't go
1994          * zero
1995          */
1996         BUG_ON(!fs_devices->num_devices && !fs_devices->seeding);
1997
1998         /* if this is no devs we rather delete the fs_devices */
1999         if (!fs_devices->num_devices) {
2000                 struct btrfs_fs_devices *tmp_fs_devices;
2001
2002                 tmp_fs_devices = fs_info->fs_devices;
2003                 while (tmp_fs_devices) {
2004                         if (tmp_fs_devices->seed == fs_devices) {
2005                                 tmp_fs_devices->seed = fs_devices->seed;
2006                                 break;
2007                         }
2008                         tmp_fs_devices = tmp_fs_devices->seed;
2009                 }
2010                 fs_devices->seed = NULL;
2011                 __btrfs_close_devices(fs_devices);
2012                 free_fs_devices(fs_devices);
2013         }
2014 }
2015
2016 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
2017                                       struct btrfs_device *tgtdev)
2018 {
2019         struct btrfs_device *next_device;
2020
2021         mutex_lock(&uuid_mutex);
2022         WARN_ON(!tgtdev);
2023         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2024
2025         btrfs_sysfs_rm_device_link(fs_info->fs_devices, tgtdev);
2026
2027         if (tgtdev->bdev) {
2028                 btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str);
2029                 fs_info->fs_devices->open_devices--;
2030         }
2031         fs_info->fs_devices->num_devices--;
2032
2033         next_device = list_entry(fs_info->fs_devices->devices.next,
2034                                  struct btrfs_device, dev_list);
2035         if (tgtdev->bdev == fs_info->sb->s_bdev)
2036                 fs_info->sb->s_bdev = next_device->bdev;
2037         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
2038                 fs_info->fs_devices->latest_bdev = next_device->bdev;
2039         list_del_rcu(&tgtdev->dev_list);
2040
2041         call_rcu(&tgtdev->rcu, free_device);
2042
2043         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2044         mutex_unlock(&uuid_mutex);
2045 }
2046
2047 static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
2048                                      struct btrfs_device **device)
2049 {
2050         int ret = 0;
2051         struct btrfs_super_block *disk_super;
2052         u64 devid;
2053         u8 *dev_uuid;
2054         struct block_device *bdev;
2055         struct buffer_head *bh;
2056
2057         *device = NULL;
2058         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
2059                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
2060         if (ret)
2061                 return ret;
2062         disk_super = (struct btrfs_super_block *)bh->b_data;
2063         devid = btrfs_stack_device_id(&disk_super->dev_item);
2064         dev_uuid = disk_super->dev_item.uuid;
2065         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
2066                                     disk_super->fsid);
2067         brelse(bh);
2068         if (!*device)
2069                 ret = -ENOENT;
2070         blkdev_put(bdev, FMODE_READ);
2071         return ret;
2072 }
2073
2074 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
2075                                          char *device_path,
2076                                          struct btrfs_device **device)
2077 {
2078         *device = NULL;
2079         if (strcmp(device_path, "missing") == 0) {
2080                 struct list_head *devices;
2081                 struct btrfs_device *tmp;
2082
2083                 devices = &root->fs_info->fs_devices->devices;
2084                 /*
2085                  * It is safe to read the devices since the volume_mutex
2086                  * is held by the caller.
2087                  */
2088                 list_for_each_entry(tmp, devices, dev_list) {
2089                         if (tmp->in_fs_metadata && !tmp->bdev) {
2090                                 *device = tmp;
2091                                 break;
2092                         }
2093                 }
2094
2095                 if (!*device)
2096                         return BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
2097
2098                 return 0;
2099         } else {
2100                 return btrfs_find_device_by_path(root, device_path, device);
2101         }
2102 }
2103
2104 /*
2105  * does all the dirty work required for changing file system's UUID.
2106  */
2107 static int btrfs_prepare_sprout(struct btrfs_root *root)
2108 {
2109         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2110         struct btrfs_fs_devices *old_devices;
2111         struct btrfs_fs_devices *seed_devices;
2112         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
2113         struct btrfs_device *device;
2114         u64 super_flags;
2115
2116         BUG_ON(!mutex_is_locked(&uuid_mutex));
2117         if (!fs_devices->seeding)
2118                 return -EINVAL;
2119
2120         seed_devices = __alloc_fs_devices();
2121         if (IS_ERR(seed_devices))
2122                 return PTR_ERR(seed_devices);
2123
2124         old_devices = clone_fs_devices(fs_devices);
2125         if (IS_ERR(old_devices)) {
2126                 kfree(seed_devices);
2127                 return PTR_ERR(old_devices);
2128         }
2129
2130         list_add(&old_devices->list, &fs_uuids);
2131
2132         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
2133         seed_devices->opened = 1;
2134         INIT_LIST_HEAD(&seed_devices->devices);
2135         INIT_LIST_HEAD(&seed_devices->alloc_list);
2136         mutex_init(&seed_devices->device_list_mutex);
2137
2138         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2139         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
2140                               synchronize_rcu);
2141         list_for_each_entry(device, &seed_devices->devices, dev_list)
2142                 device->fs_devices = seed_devices;
2143
2144         lock_chunks(root);
2145         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
2146         unlock_chunks(root);
2147
2148         fs_devices->seeding = 0;
2149         fs_devices->num_devices = 0;
2150         fs_devices->open_devices = 0;
2151         fs_devices->missing_devices = 0;
2152         fs_devices->rotating = 0;
2153         fs_devices->seed = seed_devices;
2154
2155         generate_random_uuid(fs_devices->fsid);
2156         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2157         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2158         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2159
2160         super_flags = btrfs_super_flags(disk_super) &
2161                       ~BTRFS_SUPER_FLAG_SEEDING;
2162         btrfs_set_super_flags(disk_super, super_flags);
2163
2164         return 0;
2165 }
2166
2167 /*
2168  * strore the expected generation for seed devices in device items.
2169  */
2170 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
2171                                struct btrfs_root *root)
2172 {
2173         struct btrfs_path *path;
2174         struct extent_buffer *leaf;
2175         struct btrfs_dev_item *dev_item;
2176         struct btrfs_device *device;
2177         struct btrfs_key key;
2178         u8 fs_uuid[BTRFS_UUID_SIZE];
2179         u8 dev_uuid[BTRFS_UUID_SIZE];
2180         u64 devid;
2181         int ret;
2182
2183         path = btrfs_alloc_path();
2184         if (!path)
2185                 return -ENOMEM;
2186
2187         root = root->fs_info->chunk_root;
2188         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2189         key.offset = 0;
2190         key.type = BTRFS_DEV_ITEM_KEY;
2191
2192         while (1) {
2193                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2194                 if (ret < 0)
2195                         goto error;
2196
2197                 leaf = path->nodes[0];
2198 next_slot:
2199                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
2200                         ret = btrfs_next_leaf(root, path);
2201                         if (ret > 0)
2202                                 break;
2203                         if (ret < 0)
2204                                 goto error;
2205                         leaf = path->nodes[0];
2206                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2207                         btrfs_release_path(path);
2208                         continue;
2209                 }
2210
2211                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2212                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
2213                     key.type != BTRFS_DEV_ITEM_KEY)
2214                         break;
2215
2216                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
2217                                           struct btrfs_dev_item);
2218                 devid = btrfs_device_id(leaf, dev_item);
2219                 read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
2220                                    BTRFS_UUID_SIZE);
2221                 read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
2222                                    BTRFS_UUID_SIZE);
2223                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
2224                                            fs_uuid);
2225                 BUG_ON(!device); /* Logic error */
2226
2227                 if (device->fs_devices->seeding) {
2228                         btrfs_set_device_generation(leaf, dev_item,
2229                                                     device->generation);
2230                         btrfs_mark_buffer_dirty(leaf);
2231                 }
2232
2233                 path->slots[0]++;
2234                 goto next_slot;
2235         }
2236         ret = 0;
2237 error:
2238         btrfs_free_path(path);
2239         return ret;
2240 }
2241
2242 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
2243 {
2244         struct request_queue *q;
2245         struct btrfs_trans_handle *trans;
2246         struct btrfs_device *device;
2247         struct block_device *bdev;
2248         struct list_head *devices;
2249         struct super_block *sb = root->fs_info->sb;
2250         struct rcu_string *name;
2251         u64 tmp;
2252         int seeding_dev = 0;
2253         int ret = 0;
2254
2255         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
2256                 return -EROFS;
2257
2258         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2259                                   root->fs_info->bdev_holder);
2260         if (IS_ERR(bdev))
2261                 return PTR_ERR(bdev);
2262
2263         if (root->fs_info->fs_devices->seeding) {
2264                 seeding_dev = 1;
2265                 down_write(&sb->s_umount);
2266                 mutex_lock(&uuid_mutex);
2267         }
2268
2269         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2270
2271         devices = &root->fs_info->fs_devices->devices;
2272
2273         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2274         list_for_each_entry(device, devices, dev_list) {
2275                 if (device->bdev == bdev) {
2276                         ret = -EEXIST;
2277                         mutex_unlock(
2278                                 &root->fs_info->fs_devices->device_list_mutex);
2279                         goto error;
2280                 }
2281         }
2282         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2283
2284         device = btrfs_alloc_device(root->fs_info, NULL, NULL);
2285         if (IS_ERR(device)) {
2286                 /* we can safely leave the fs_devices entry around */
2287                 ret = PTR_ERR(device);
2288                 goto error;
2289         }
2290
2291         name = rcu_string_strdup(device_path, GFP_NOFS);
2292         if (!name) {
2293                 kfree(device);
2294                 ret = -ENOMEM;
2295                 goto error;
2296         }
2297         rcu_assign_pointer(device->name, name);
2298
2299         trans = btrfs_start_transaction(root, 0);
2300         if (IS_ERR(trans)) {
2301                 rcu_string_free(device->name);
2302                 kfree(device);
2303                 ret = PTR_ERR(trans);
2304                 goto error;
2305         }
2306
2307         q = bdev_get_queue(bdev);
2308         if (blk_queue_discard(q))
2309                 device->can_discard = 1;
2310         device->writeable = 1;
2311         device->generation = trans->transid;
2312         device->io_width = root->sectorsize;
2313         device->io_align = root->sectorsize;
2314         device->sector_size = root->sectorsize;
2315         device->total_bytes = i_size_read(bdev->bd_inode);
2316         device->disk_total_bytes = device->total_bytes;
2317         device->commit_total_bytes = device->total_bytes;
2318         device->dev_root = root->fs_info->dev_root;
2319         device->bdev = bdev;
2320         device->in_fs_metadata = 1;
2321         device->is_tgtdev_for_dev_replace = 0;
2322         device->mode = FMODE_EXCL;
2323         device->dev_stats_valid = 1;
2324         set_blocksize(device->bdev, 4096);
2325
2326         if (seeding_dev) {
2327                 sb->s_flags &= ~MS_RDONLY;
2328                 ret = btrfs_prepare_sprout(root);
2329                 BUG_ON(ret); /* -ENOMEM */
2330         }
2331
2332         device->fs_devices = root->fs_info->fs_devices;
2333
2334         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2335         lock_chunks(root);
2336         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
2337         list_add(&device->dev_alloc_list,
2338                  &root->fs_info->fs_devices->alloc_list);
2339         root->fs_info->fs_devices->num_devices++;
2340         root->fs_info->fs_devices->open_devices++;
2341         root->fs_info->fs_devices->rw_devices++;
2342         root->fs_info->fs_devices->total_devices++;
2343         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
2344
2345         spin_lock(&root->fs_info->free_chunk_lock);
2346         root->fs_info->free_chunk_space += device->total_bytes;
2347         spin_unlock(&root->fs_info->free_chunk_lock);
2348
2349         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
2350                 root->fs_info->fs_devices->rotating = 1;
2351
2352         tmp = btrfs_super_total_bytes(root->fs_info->super_copy);
2353         btrfs_set_super_total_bytes(root->fs_info->super_copy,
2354                                     tmp + device->total_bytes);
2355
2356         tmp = btrfs_super_num_devices(root->fs_info->super_copy);
2357         btrfs_set_super_num_devices(root->fs_info->super_copy,
2358                                     tmp + 1);
2359
2360         /*
2361          * we've got more storage, clear any full flags on the space
2362          * infos
2363          */
2364         btrfs_clear_space_info_full(root->fs_info);
2365
2366         unlock_chunks(root);
2367
2368         /* add sysfs device entry */
2369         btrfs_sysfs_add_device_link(root->fs_info->fs_devices, device);
2370
2371         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2372
2373         if (seeding_dev) {
2374                 lock_chunks(root);
2375                 ret = init_first_rw_device(trans, root, device);
2376                 unlock_chunks(root);
2377                 if (ret) {
2378                         btrfs_abort_transaction(trans, root, ret);
2379                         goto error_trans;
2380                 }
2381         }
2382
2383         ret = btrfs_add_device(trans, root, device);
2384         if (ret) {
2385                 btrfs_abort_transaction(trans, root, ret);
2386                 goto error_trans;
2387         }
2388
2389         if (seeding_dev) {
2390                 char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
2391
2392                 ret = btrfs_finish_sprout(trans, root);
2393                 if (ret) {
2394                         btrfs_abort_transaction(trans, root, ret);
2395                         goto error_trans;
2396                 }
2397
2398                 /* Sprouting would change fsid of the mounted root,
2399                  * so rename the fsid on the sysfs
2400                  */
2401                 snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU",
2402                                                 root->fs_info->fsid);
2403                 if (kobject_rename(&root->fs_info->fs_devices->fsid_kobj,
2404                                                                 fsid_buf))
2405                         btrfs_warn(root->fs_info,
2406                                 "sysfs: failed to create fsid for sprout");
2407         }
2408
2409         root->fs_info->num_tolerated_disk_barrier_failures =
2410                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
2411         ret = btrfs_commit_transaction(trans, root);
2412
2413         if (seeding_dev) {
2414                 mutex_unlock(&uuid_mutex);
2415                 up_write(&sb->s_umount);
2416
2417                 if (ret) /* transaction commit */
2418                         return ret;
2419
2420                 ret = btrfs_relocate_sys_chunks(root);
2421                 if (ret < 0)
2422                         btrfs_std_error(root->fs_info, ret,
2423                                     "Failed to relocate sys chunks after "
2424                                     "device initialization. This can be fixed "
2425                                     "using the \"btrfs balance\" command.");
2426                 trans = btrfs_attach_transaction(root);
2427                 if (IS_ERR(trans)) {
2428                         if (PTR_ERR(trans) == -ENOENT)
2429                                 return 0;
2430                         return PTR_ERR(trans);
2431                 }
2432                 ret = btrfs_commit_transaction(trans, root);
2433         }
2434
2435         /* Update ctime/mtime for libblkid */
2436         update_dev_time(device_path);
2437         return ret;
2438
2439 error_trans:
2440         btrfs_end_transaction(trans, root);
2441         rcu_string_free(device->name);
2442         btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
2443         kfree(device);
2444 error:
2445         blkdev_put(bdev, FMODE_EXCL);
2446         if (seeding_dev) {
2447                 mutex_unlock(&uuid_mutex);
2448                 up_write(&sb->s_umount);
2449         }
2450         return ret;
2451 }
2452
2453 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2454                                   struct btrfs_device *srcdev,
2455                                   struct btrfs_device **device_out)
2456 {
2457         struct request_queue *q;
2458         struct btrfs_device *device;
2459         struct block_device *bdev;
2460         struct btrfs_fs_info *fs_info = root->fs_info;
2461         struct list_head *devices;
2462         struct rcu_string *name;
2463         u64 devid = BTRFS_DEV_REPLACE_DEVID;
2464         int ret = 0;
2465
2466         *device_out = NULL;
2467         if (fs_info->fs_devices->seeding) {
2468                 btrfs_err(fs_info, "the filesystem is a seed filesystem!");
2469                 return -EINVAL;
2470         }
2471
2472         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2473                                   fs_info->bdev_holder);
2474         if (IS_ERR(bdev)) {
2475                 btrfs_err(fs_info, "target device %s is invalid!", device_path);
2476                 return PTR_ERR(bdev);
2477         }
2478
2479         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2480
2481         devices = &fs_info->fs_devices->devices;
2482         list_for_each_entry(device, devices, dev_list) {
2483                 if (device->bdev == bdev) {
2484                         btrfs_err(fs_info, "target device is in the filesystem!");
2485                         ret = -EEXIST;
2486                         goto error;
2487                 }
2488         }
2489
2490
2491         if (i_size_read(bdev->bd_inode) <
2492             btrfs_device_get_total_bytes(srcdev)) {
2493                 btrfs_err(fs_info, "target device is smaller than source device!");
2494                 ret = -EINVAL;
2495                 goto error;
2496         }
2497
2498
2499         device = btrfs_alloc_device(NULL, &devid, NULL);
2500         if (IS_ERR(device)) {
2501                 ret = PTR_ERR(device);
2502                 goto error;
2503         }
2504
2505         name = rcu_string_strdup(device_path, GFP_NOFS);
2506         if (!name) {
2507                 kfree(device);
2508                 ret = -ENOMEM;
2509                 goto error;
2510         }
2511         rcu_assign_pointer(device->name, name);
2512
2513         q = bdev_get_queue(bdev);
2514         if (blk_queue_discard(q))
2515                 device->can_discard = 1;
2516         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2517         device->writeable = 1;
2518         device->generation = 0;
2519         device->io_width = root->sectorsize;
2520         device->io_align = root->sectorsize;
2521         device->sector_size = root->sectorsize;
2522         device->total_bytes = btrfs_device_get_total_bytes(srcdev);
2523         device->disk_total_bytes = btrfs_device_get_disk_total_bytes(srcdev);
2524         device->bytes_used = btrfs_device_get_bytes_used(srcdev);
2525         ASSERT(list_empty(&srcdev->resized_list));
2526         device->commit_total_bytes = srcdev->commit_total_bytes;
2527         device->commit_bytes_used = device->bytes_used;
2528         device->dev_root = fs_info->dev_root;
2529         device->bdev = bdev;
2530         device->in_fs_metadata = 1;
2531         device->is_tgtdev_for_dev_replace = 1;
2532         device->mode = FMODE_EXCL;
2533         device->dev_stats_valid = 1;
2534         set_blocksize(device->bdev, 4096);
2535         device->fs_devices = fs_info->fs_devices;
2536         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2537         fs_info->fs_devices->num_devices++;
2538         fs_info->fs_devices->open_devices++;
2539         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2540
2541         *device_out = device;
2542         return ret;
2543
2544 error:
2545         blkdev_put(bdev, FMODE_EXCL);
2546         return ret;
2547 }
2548
2549 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2550                                               struct btrfs_device *tgtdev)
2551 {
2552         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2553         tgtdev->io_width = fs_info->dev_root->sectorsize;
2554         tgtdev->io_align = fs_info->dev_root->sectorsize;
2555         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2556         tgtdev->dev_root = fs_info->dev_root;
2557         tgtdev->in_fs_metadata = 1;
2558 }
2559
2560 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2561                                         struct btrfs_device *device)
2562 {
2563         int ret;
2564         struct btrfs_path *path;
2565         struct btrfs_root *root;
2566         struct btrfs_dev_item *dev_item;
2567         struct extent_buffer *leaf;
2568         struct btrfs_key key;
2569
2570         root = device->dev_root->fs_info->chunk_root;
2571
2572         path = btrfs_alloc_path();
2573         if (!path)
2574                 return -ENOMEM;
2575
2576         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2577         key.type = BTRFS_DEV_ITEM_KEY;
2578         key.offset = device->devid;
2579
2580         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2581         if (ret < 0)
2582                 goto out;
2583
2584         if (ret > 0) {
2585                 ret = -ENOENT;
2586                 goto out;
2587         }
2588
2589         leaf = path->nodes[0];
2590         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2591
2592         btrfs_set_device_id(leaf, dev_item, device->devid);
2593         btrfs_set_device_type(leaf, dev_item, device->type);
2594         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2595         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2596         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2597         btrfs_set_device_total_bytes(leaf, dev_item,
2598                                      btrfs_device_get_disk_total_bytes(device));
2599         btrfs_set_device_bytes_used(leaf, dev_item,
2600                                     btrfs_device_get_bytes_used(device));
2601         btrfs_mark_buffer_dirty(leaf);
2602
2603 out:
2604         btrfs_free_path(path);
2605         return ret;
2606 }
2607
2608 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2609                       struct btrfs_device *device, u64 new_size)
2610 {
2611         struct btrfs_super_block *super_copy =
2612                 device->dev_root->fs_info->super_copy;
2613         struct btrfs_fs_devices *fs_devices;
2614         u64 old_total;
2615         u64 diff;
2616
2617         if (!device->writeable)
2618                 return -EACCES;
2619
2620         lock_chunks(device->dev_root);
2621         old_total = btrfs_super_total_bytes(super_copy);
2622         diff = new_size - device->total_bytes;
2623
2624         if (new_size <= device->total_bytes ||
2625             device->is_tgtdev_for_dev_replace) {
2626                 unlock_chunks(device->dev_root);
2627                 return -EINVAL;
2628         }
2629
2630         fs_devices = device->dev_root->fs_info->fs_devices;
2631
2632         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2633         device->fs_devices->total_rw_bytes += diff;
2634
2635         btrfs_device_set_total_bytes(device, new_size);
2636         btrfs_device_set_disk_total_bytes(device, new_size);
2637         btrfs_clear_space_info_full(device->dev_root->fs_info);
2638         if (list_empty(&device->resized_list))
2639                 list_add_tail(&device->resized_list,
2640                               &fs_devices->resized_devices);
2641         unlock_chunks(device->dev_root);
2642
2643         return btrfs_update_device(trans, device);
2644 }
2645
2646 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2647                             struct btrfs_root *root, u64 chunk_objectid,
2648                             u64 chunk_offset)
2649 {
2650         int ret;
2651         struct btrfs_path *path;
2652         struct btrfs_key key;
2653
2654         root = root->fs_info->chunk_root;
2655         path = btrfs_alloc_path();
2656         if (!path)
2657                 return -ENOMEM;
2658
2659         key.objectid = chunk_objectid;
2660         key.offset = chunk_offset;
2661         key.type = BTRFS_CHUNK_ITEM_KEY;
2662
2663         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2664         if (ret < 0)
2665                 goto out;
2666         else if (ret > 0) { /* Logic error or corruption */
2667                 btrfs_std_error(root->fs_info, -ENOENT,
2668                             "Failed lookup while freeing chunk.");
2669                 ret = -ENOENT;
2670                 goto out;
2671         }
2672
2673         ret = btrfs_del_item(trans, root, path);
2674         if (ret < 0)
2675                 btrfs_std_error(root->fs_info, ret,
2676                             "Failed to delete chunk item.");
2677 out:
2678         btrfs_free_path(path);
2679         return ret;
2680 }
2681
2682 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2683                         chunk_offset)
2684 {
2685         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2686         struct btrfs_disk_key *disk_key;
2687         struct btrfs_chunk *chunk;
2688         u8 *ptr;
2689         int ret = 0;
2690         u32 num_stripes;
2691         u32 array_size;
2692         u32 len = 0;
2693         u32 cur;
2694         struct btrfs_key key;
2695
2696         lock_chunks(root);
2697         array_size = btrfs_super_sys_array_size(super_copy);
2698
2699         ptr = super_copy->sys_chunk_array;
2700         cur = 0;
2701
2702         while (cur < array_size) {
2703                 disk_key = (struct btrfs_disk_key *)ptr;
2704                 btrfs_disk_key_to_cpu(&key, disk_key);
2705
2706                 len = sizeof(*disk_key);
2707
2708                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2709                         chunk = (struct btrfs_chunk *)(ptr + len);
2710                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2711                         len += btrfs_chunk_item_size(num_stripes);
2712                 } else {
2713                         ret = -EIO;
2714                         break;
2715                 }
2716                 if (key.objectid == chunk_objectid &&
2717                     key.offset == chunk_offset) {
2718                         memmove(ptr, ptr + len, array_size - (cur + len));
2719                         array_size -= len;
2720                         btrfs_set_super_sys_array_size(super_copy, array_size);
2721                 } else {
2722                         ptr += len;
2723                         cur += len;
2724                 }
2725         }
2726         unlock_chunks(root);
2727         return ret;
2728 }
2729
2730 int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
2731                        struct btrfs_root *root, u64 chunk_offset)
2732 {
2733         struct extent_map_tree *em_tree;
2734         struct extent_map *em;
2735         struct btrfs_root *extent_root = root->fs_info->extent_root;
2736         struct map_lookup *map;
2737         u64 dev_extent_len = 0;
2738         u64 chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2739         int i, ret = 0;
2740
2741         /* Just in case */
2742         root = root->fs_info->chunk_root;
2743         em_tree = &root->fs_info->mapping_tree.map_tree;
2744
2745         read_lock(&em_tree->lock);
2746         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2747         read_unlock(&em_tree->lock);
2748
2749         if (!em || em->start > chunk_offset ||
2750             em->start + em->len < chunk_offset) {
2751                 /*
2752                  * This is a logic error, but we don't want to just rely on the
2753                  * user having built with ASSERT enabled, so if ASSERT doens't
2754                  * do anything we still error out.
2755                  */
2756                 ASSERT(0);
2757                 if (em)
2758                         free_extent_map(em);
2759                 return -EINVAL;
2760         }
2761         map = em->map_lookup;
2762         lock_chunks(root->fs_info->chunk_root);
2763         check_system_chunk(trans, extent_root, map->type);
2764         unlock_chunks(root->fs_info->chunk_root);
2765
2766         for (i = 0; i < map->num_stripes; i++) {
2767                 struct btrfs_device *device = map->stripes[i].dev;
2768                 ret = btrfs_free_dev_extent(trans, device,
2769                                             map->stripes[i].physical,
2770                                             &dev_extent_len);
2771                 if (ret) {
2772                         btrfs_abort_transaction(trans, root, ret);
2773                         goto out;
2774                 }
2775
2776                 if (device->bytes_used > 0) {
2777                         lock_chunks(root);
2778                         btrfs_device_set_bytes_used(device,
2779                                         device->bytes_used - dev_extent_len);
2780                         spin_lock(&root->fs_info->free_chunk_lock);
2781                         root->fs_info->free_chunk_space += dev_extent_len;
2782                         spin_unlock(&root->fs_info->free_chunk_lock);
2783                         btrfs_clear_space_info_full(root->fs_info);
2784                         unlock_chunks(root);
2785                 }
2786
2787                 if (map->stripes[i].dev) {
2788                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2789                         if (ret) {
2790                                 btrfs_abort_transaction(trans, root, ret);
2791                                 goto out;
2792                         }
2793                 }
2794         }
2795         ret = btrfs_free_chunk(trans, root, chunk_objectid, chunk_offset);
2796         if (ret) {
2797                 btrfs_abort_transaction(trans, root, ret);
2798                 goto out;
2799         }
2800
2801         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2802
2803         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2804                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2805                 if (ret) {
2806                         btrfs_abort_transaction(trans, root, ret);
2807                         goto out;
2808                 }
2809         }
2810
2811         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset, em);
2812         if (ret) {
2813                 btrfs_abort_transaction(trans, extent_root, ret);
2814                 goto out;
2815         }
2816
2817 out:
2818         /* once for us */
2819         free_extent_map(em);
2820         return ret;
2821 }
2822
2823 static int btrfs_relocate_chunk(struct btrfs_root *root, u64 chunk_offset)
2824 {
2825         struct btrfs_root *extent_root;
2826         struct btrfs_trans_handle *trans;
2827         int ret;
2828
2829         root = root->fs_info->chunk_root;
2830         extent_root = root->fs_info->extent_root;
2831
2832         /*
2833          * Prevent races with automatic removal of unused block groups.
2834          * After we relocate and before we remove the chunk with offset
2835          * chunk_offset, automatic removal of the block group can kick in,
2836          * resulting in a failure when calling btrfs_remove_chunk() below.
2837          *
2838          * Make sure to acquire this mutex before doing a tree search (dev
2839          * or chunk trees) to find chunks. Otherwise the cleaner kthread might
2840          * call btrfs_remove_chunk() (through btrfs_delete_unused_bgs()) after
2841          * we release the path used to search the chunk/dev tree and before
2842          * the current task acquires this mutex and calls us.
2843          */
2844         ASSERT(mutex_is_locked(&root->fs_info->delete_unused_bgs_mutex));
2845
2846         ret = btrfs_can_relocate(extent_root, chunk_offset);
2847         if (ret)
2848                 return -ENOSPC;
2849
2850         /* step one, relocate all the extents inside this chunk */
2851         btrfs_scrub_pause(root);
2852         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2853         btrfs_scrub_continue(root);
2854         if (ret)
2855                 return ret;
2856
2857         trans = btrfs_start_trans_remove_block_group(root->fs_info,
2858                                                      chunk_offset);
2859         if (IS_ERR(trans)) {
2860                 ret = PTR_ERR(trans);
2861                 btrfs_std_error(root->fs_info, ret, NULL);
2862                 return ret;
2863         }
2864
2865         /*
2866          * step two, delete the device extents and the
2867          * chunk tree entries
2868          */
2869         ret = btrfs_remove_chunk(trans, root, chunk_offset);
2870         btrfs_end_transaction(trans, root);
2871         return ret;
2872 }
2873
2874 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2875 {
2876         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2877         struct btrfs_path *path;
2878         struct extent_buffer *leaf;
2879         struct btrfs_chunk *chunk;
2880         struct btrfs_key key;
2881         struct btrfs_key found_key;
2882         u64 chunk_type;
2883         bool retried = false;
2884         int failed = 0;
2885         int ret;
2886
2887         path = btrfs_alloc_path();
2888         if (!path)
2889                 return -ENOMEM;
2890
2891 again:
2892         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2893         key.offset = (u64)-1;
2894         key.type = BTRFS_CHUNK_ITEM_KEY;
2895
2896         while (1) {
2897                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
2898                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2899                 if (ret < 0) {
2900                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2901                         goto error;
2902                 }
2903                 BUG_ON(ret == 0); /* Corruption */
2904
2905                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2906                                           key.type);
2907                 if (ret)
2908                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2909                 if (ret < 0)
2910                         goto error;
2911                 if (ret > 0)
2912                         break;
2913
2914                 leaf = path->nodes[0];
2915                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2916
2917                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2918                                        struct btrfs_chunk);
2919                 chunk_type = btrfs_chunk_type(leaf, chunk);
2920                 btrfs_release_path(path);
2921
2922                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2923                         ret = btrfs_relocate_chunk(chunk_root,
2924                                                    found_key.offset);
2925                         if (ret == -ENOSPC)
2926                                 failed++;
2927                         else
2928                                 BUG_ON(ret);
2929                 }
2930                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2931
2932                 if (found_key.offset == 0)
2933                         break;
2934                 key.offset = found_key.offset - 1;
2935         }
2936         ret = 0;
2937         if (failed && !retried) {
2938                 failed = 0;
2939                 retried = true;
2940                 goto again;
2941         } else if (WARN_ON(failed && retried)) {
2942                 ret = -ENOSPC;
2943         }
2944 error:
2945         btrfs_free_path(path);
2946         return ret;
2947 }
2948
2949 static int insert_balance_item(struct btrfs_root *root,
2950                                struct btrfs_balance_control *bctl)
2951 {
2952         struct btrfs_trans_handle *trans;
2953         struct btrfs_balance_item *item;
2954         struct btrfs_disk_balance_args disk_bargs;
2955         struct btrfs_path *path;
2956         struct extent_buffer *leaf;
2957         struct btrfs_key key;
2958         int ret, err;
2959
2960         path = btrfs_alloc_path();
2961         if (!path)
2962                 return -ENOMEM;
2963
2964         trans = btrfs_start_transaction(root, 0);
2965         if (IS_ERR(trans)) {
2966                 btrfs_free_path(path);
2967                 return PTR_ERR(trans);
2968         }
2969
2970         key.objectid = BTRFS_BALANCE_OBJECTID;
2971         key.type = BTRFS_BALANCE_ITEM_KEY;
2972         key.offset = 0;
2973
2974         ret = btrfs_insert_empty_item(trans, root, path, &key,
2975                                       sizeof(*item));
2976         if (ret)
2977                 goto out;
2978
2979         leaf = path->nodes[0];
2980         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2981
2982         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2983
2984         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2985         btrfs_set_balance_data(leaf, item, &disk_bargs);
2986         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2987         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2988         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2989         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2990
2991         btrfs_set_balance_flags(leaf, item, bctl->flags);
2992
2993         btrfs_mark_buffer_dirty(leaf);
2994 out:
2995         btrfs_free_path(path);
2996         err = btrfs_commit_transaction(trans, root);
2997         if (err && !ret)
2998                 ret = err;
2999         return ret;
3000 }
3001
3002 static int del_balance_item(struct btrfs_root *root)
3003 {
3004         struct btrfs_trans_handle *trans;
3005         struct btrfs_path *path;
3006         struct btrfs_key key;
3007         int ret, err;
3008
3009         path = btrfs_alloc_path();
3010         if (!path)
3011                 return -ENOMEM;
3012
3013         trans = btrfs_start_transaction(root, 0);
3014         if (IS_ERR(trans)) {
3015                 btrfs_free_path(path);
3016                 return PTR_ERR(trans);
3017         }
3018
3019         key.objectid = BTRFS_BALANCE_OBJECTID;
3020         key.type = BTRFS_BALANCE_ITEM_KEY;
3021         key.offset = 0;
3022
3023         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3024         if (ret < 0)
3025                 goto out;
3026         if (ret > 0) {
3027                 ret = -ENOENT;
3028                 goto out;
3029         }
3030
3031         ret = btrfs_del_item(trans, root, path);
3032 out:
3033         btrfs_free_path(path);
3034         err = btrfs_commit_transaction(trans, root);
3035         if (err && !ret)
3036                 ret = err;
3037         return ret;
3038 }
3039
3040 /*
3041  * This is a heuristic used to reduce the number of chunks balanced on
3042  * resume after balance was interrupted.
3043  */
3044 static void update_balance_args(struct btrfs_balance_control *bctl)
3045 {
3046         /*
3047          * Turn on soft mode for chunk types that were being converted.
3048          */
3049         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
3050                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
3051         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
3052                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
3053         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
3054                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
3055
3056         /*
3057          * Turn on usage filter if is not already used.  The idea is
3058          * that chunks that we have already balanced should be
3059          * reasonably full.  Don't do it for chunks that are being
3060          * converted - that will keep us from relocating unconverted
3061          * (albeit full) chunks.
3062          */
3063         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3064             !(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3065             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3066                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
3067                 bctl->data.usage = 90;
3068         }
3069         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3070             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3071             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3072                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
3073                 bctl->sys.usage = 90;
3074         }
3075         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3076             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3077             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3078                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
3079                 bctl->meta.usage = 90;
3080         }
3081 }
3082
3083 /*
3084  * Should be called with both balance and volume mutexes held to
3085  * serialize other volume operations (add_dev/rm_dev/resize) with
3086  * restriper.  Same goes for unset_balance_control.
3087  */
3088 static void set_balance_control(struct btrfs_balance_control *bctl)
3089 {
3090         struct btrfs_fs_info *fs_info = bctl->fs_info;
3091
3092         BUG_ON(fs_info->balance_ctl);
3093
3094         spin_lock(&fs_info->balance_lock);
3095         fs_info->balance_ctl = bctl;
3096         spin_unlock(&fs_info->balance_lock);
3097 }
3098
3099 static void unset_balance_control(struct btrfs_fs_info *fs_info)
3100 {
3101         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3102
3103         BUG_ON(!fs_info->balance_ctl);
3104
3105         spin_lock(&fs_info->balance_lock);
3106         fs_info->balance_ctl = NULL;
3107         spin_unlock(&fs_info->balance_lock);
3108
3109         kfree(bctl);
3110 }
3111
3112 /*
3113  * Balance filters.  Return 1 if chunk should be filtered out
3114  * (should not be balanced).
3115  */
3116 static int chunk_profiles_filter(u64 chunk_type,
3117                                  struct btrfs_balance_args *bargs)
3118 {
3119         chunk_type = chunk_to_extended(chunk_type) &
3120                                 BTRFS_EXTENDED_PROFILE_MASK;
3121
3122         if (bargs->profiles & chunk_type)
3123                 return 0;
3124
3125         return 1;
3126 }
3127
3128 static int chunk_usage_range_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
3129                               struct btrfs_balance_args *bargs)
3130 {
3131         struct btrfs_block_group_cache *cache;
3132         u64 chunk_used;
3133         u64 user_thresh_min;
3134         u64 user_thresh_max;
3135         int ret = 1;
3136
3137         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3138         chunk_used = btrfs_block_group_used(&cache->item);
3139
3140         if (bargs->usage_min == 0)
3141                 user_thresh_min = 0;
3142         else
3143                 user_thresh_min = div_factor_fine(cache->key.offset,
3144                                         bargs->usage_min);
3145
3146         if (bargs->usage_max == 0)
3147                 user_thresh_max = 1;
3148         else if (bargs->usage_max > 100)
3149                 user_thresh_max = cache->key.offset;
3150         else
3151                 user_thresh_max = div_factor_fine(cache->key.offset,
3152                                         bargs->usage_max);
3153
3154         if (user_thresh_min <= chunk_used && chunk_used < user_thresh_max)
3155                 ret = 0;
3156
3157         btrfs_put_block_group(cache);
3158         return ret;
3159 }
3160
3161 static int chunk_usage_filter(struct btrfs_fs_info *fs_info,
3162                 u64 chunk_offset, struct btrfs_balance_args *bargs)
3163 {
3164         struct btrfs_block_group_cache *cache;
3165         u64 chunk_used, user_thresh;
3166         int ret = 1;
3167
3168         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3169         chunk_used = btrfs_block_group_used(&cache->item);
3170
3171         if (bargs->usage_min == 0)
3172                 user_thresh = 1;
3173         else if (bargs->usage > 100)
3174                 user_thresh = cache->key.offset;
3175         else
3176                 user_thresh = div_factor_fine(cache->key.offset,
3177                                               bargs->usage);
3178
3179         if (chunk_used < user_thresh)
3180                 ret = 0;
3181
3182         btrfs_put_block_group(cache);
3183         return ret;
3184 }
3185
3186 static int chunk_devid_filter(struct extent_buffer *leaf,
3187                               struct btrfs_chunk *chunk,
3188                               struct btrfs_balance_args *bargs)
3189 {
3190         struct btrfs_stripe *stripe;
3191         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3192         int i;
3193
3194         for (i = 0; i < num_stripes; i++) {
3195                 stripe = btrfs_stripe_nr(chunk, i);
3196                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
3197                         return 0;
3198         }
3199
3200         return 1;
3201 }
3202
3203 /* [pstart, pend) */
3204 static int chunk_drange_filter(struct extent_buffer *leaf,
3205                                struct btrfs_chunk *chunk,
3206                                u64 chunk_offset,
3207                                struct btrfs_balance_args *bargs)
3208 {
3209         struct btrfs_stripe *stripe;
3210         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3211         u64 stripe_offset;
3212         u64 stripe_length;
3213         int factor;
3214         int i;
3215
3216         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
3217                 return 0;
3218
3219         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
3220              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) {
3221                 factor = num_stripes / 2;
3222         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) {
3223                 factor = num_stripes - 1;
3224         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) {
3225                 factor = num_stripes - 2;
3226         } else {
3227                 factor = num_stripes;
3228         }
3229
3230         for (i = 0; i < num_stripes; i++) {
3231                 stripe = btrfs_stripe_nr(chunk, i);
3232                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
3233                         continue;
3234
3235                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
3236                 stripe_length = btrfs_chunk_length(leaf, chunk);
3237                 stripe_length = div_u64(stripe_length, factor);
3238
3239                 if (stripe_offset < bargs->pend &&
3240                     stripe_offset + stripe_length > bargs->pstart)
3241                         return 0;
3242         }
3243
3244         return 1;
3245 }
3246
3247 /* [vstart, vend) */
3248 static int chunk_vrange_filter(struct extent_buffer *leaf,
3249                                struct btrfs_chunk *chunk,
3250                                u64 chunk_offset,
3251                                struct btrfs_balance_args *bargs)
3252 {
3253         if (chunk_offset < bargs->vend &&
3254             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
3255                 /* at least part of the chunk is inside this vrange */
3256                 return 0;
3257
3258         return 1;
3259 }
3260
3261 static int chunk_stripes_range_filter(struct extent_buffer *leaf,
3262                                struct btrfs_chunk *chunk,
3263                                struct btrfs_balance_args *bargs)
3264 {
3265         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3266
3267         if (bargs->stripes_min <= num_stripes
3268                         && num_stripes <= bargs->stripes_max)
3269                 return 0;
3270
3271         return 1;
3272 }
3273
3274 static int chunk_soft_convert_filter(u64 chunk_type,
3275                                      struct btrfs_balance_args *bargs)
3276 {
3277         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
3278                 return 0;
3279
3280         chunk_type = chunk_to_extended(chunk_type) &
3281                                 BTRFS_EXTENDED_PROFILE_MASK;
3282
3283         if (bargs->target == chunk_type)
3284                 return 1;
3285
3286         return 0;
3287 }
3288
3289 static int should_balance_chunk(struct btrfs_root *root,
3290                                 struct extent_buffer *leaf,
3291                                 struct btrfs_chunk *chunk, u64 chunk_offset)
3292 {
3293         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
3294         struct btrfs_balance_args *bargs = NULL;
3295         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
3296
3297         /* type filter */
3298         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
3299               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
3300                 return 0;
3301         }
3302
3303         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3304                 bargs = &bctl->data;
3305         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3306                 bargs = &bctl->sys;
3307         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3308                 bargs = &bctl->meta;
3309
3310         /* profiles filter */
3311         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
3312             chunk_profiles_filter(chunk_type, bargs)) {
3313                 return 0;
3314         }
3315
3316         /* usage filter */
3317         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
3318             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
3319                 return 0;
3320         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3321             chunk_usage_range_filter(bctl->fs_info, chunk_offset, bargs)) {
3322                 return 0;
3323         }
3324
3325         /* devid filter */
3326         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
3327             chunk_devid_filter(leaf, chunk, bargs)) {
3328                 return 0;
3329         }
3330
3331         /* drange filter, makes sense only with devid filter */
3332         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
3333             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
3334                 return 0;
3335         }
3336
3337         /* vrange filter */
3338         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
3339             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
3340                 return 0;
3341         }
3342
3343         /* stripes filter */
3344         if ((bargs->flags & BTRFS_BALANCE_ARGS_STRIPES_RANGE) &&
3345             chunk_stripes_range_filter(leaf, chunk, bargs)) {
3346                 return 0;
3347         }
3348
3349         /* soft profile changing mode */
3350         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
3351             chunk_soft_convert_filter(chunk_type, bargs)) {
3352                 return 0;
3353         }
3354
3355         /*
3356          * limited by count, must be the last filter
3357          */
3358         if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT)) {
3359                 if (bargs->limit == 0)
3360                         return 0;
3361                 else
3362                         bargs->limit--;
3363         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE)) {
3364                 /*
3365                  * Same logic as the 'limit' filter; the minimum cannot be
3366                  * determined here because we do not have the global informatoin
3367                  * about the count of all chunks that satisfy the filters.
3368                  */
3369                 if (bargs->limit_max == 0)
3370                         return 0;
3371                 else
3372                         bargs->limit_max--;
3373         }
3374
3375         return 1;
3376 }
3377
3378 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
3379 {
3380         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3381         struct btrfs_root *chunk_root = fs_info->chunk_root;
3382         struct btrfs_root *dev_root = fs_info->dev_root;
3383         struct list_head *devices;
3384         struct btrfs_device *device;
3385         u64 old_size;
3386         u64 size_to_free;
3387         u64 chunk_type;
3388         struct btrfs_chunk *chunk;
3389         struct btrfs_path *path;
3390         struct btrfs_key key;
3391         struct btrfs_key found_key;
3392         struct btrfs_trans_handle *trans;
3393         struct extent_buffer *leaf;
3394         int slot;
3395         int ret;
3396         int enospc_errors = 0;
3397         bool counting = true;
3398         /* The single value limit and min/max limits use the same bytes in the */
3399         u64 limit_data = bctl->data.limit;
3400         u64 limit_meta = bctl->meta.limit;
3401         u64 limit_sys = bctl->sys.limit;
3402         u32 count_data = 0;
3403         u32 count_meta = 0;
3404         u32 count_sys = 0;
3405         int chunk_reserved = 0;
3406
3407         /* step one make some room on all the devices */
3408         devices = &fs_info->fs_devices->devices;
3409         list_for_each_entry(device, devices, dev_list) {
3410                 old_size = btrfs_device_get_total_bytes(device);
3411                 size_to_free = div_factor(old_size, 1);
3412                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
3413                 if (!device->writeable ||
3414                     btrfs_device_get_total_bytes(device) -
3415                     btrfs_device_get_bytes_used(device) > size_to_free ||
3416                     device->is_tgtdev_for_dev_replace)
3417                         continue;
3418
3419                 ret = btrfs_shrink_device(device, old_size - size_to_free);
3420                 if (ret == -ENOSPC)
3421                         break;
3422                 BUG_ON(ret);
3423
3424                 trans = btrfs_start_transaction(dev_root, 0);
3425                 BUG_ON(IS_ERR(trans));
3426
3427                 ret = btrfs_grow_device(trans, device, old_size);
3428                 BUG_ON(ret);
3429
3430                 btrfs_end_transaction(trans, dev_root);
3431         }
3432
3433         /* step two, relocate all the chunks */
3434         path = btrfs_alloc_path();
3435         if (!path) {
3436                 ret = -ENOMEM;
3437                 goto error;
3438         }
3439
3440         /* zero out stat counters */
3441         spin_lock(&fs_info->balance_lock);
3442         memset(&bctl->stat, 0, sizeof(bctl->stat));
3443         spin_unlock(&fs_info->balance_lock);
3444 again:
3445         if (!counting) {
3446                 /*
3447                  * The single value limit and min/max limits use the same bytes
3448                  * in the
3449                  */
3450                 bctl->data.limit = limit_data;
3451                 bctl->meta.limit = limit_meta;
3452                 bctl->sys.limit = limit_sys;
3453         }
3454         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3455         key.offset = (u64)-1;
3456         key.type = BTRFS_CHUNK_ITEM_KEY;
3457
3458         while (1) {
3459                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
3460                     atomic_read(&fs_info->balance_cancel_req)) {
3461                         ret = -ECANCELED;
3462                         goto error;
3463                 }
3464
3465                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
3466                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
3467                 if (ret < 0) {
3468                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3469                         goto error;
3470                 }
3471
3472                 /*
3473                  * this shouldn't happen, it means the last relocate
3474                  * failed
3475                  */
3476                 if (ret == 0)
3477                         BUG(); /* FIXME break ? */
3478
3479                 ret = btrfs_previous_item(chunk_root, path, 0,
3480                                           BTRFS_CHUNK_ITEM_KEY);
3481                 if (ret) {
3482                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3483                         ret = 0;
3484                         break;
3485                 }
3486
3487                 leaf = path->nodes[0];
3488                 slot = path->slots[0];
3489                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3490
3491                 if (found_key.objectid != key.objectid) {
3492                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3493                         break;
3494                 }
3495
3496                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3497                 chunk_type = btrfs_chunk_type(leaf, chunk);
3498
3499                 if (!counting) {
3500                         spin_lock(&fs_info->balance_lock);
3501                         bctl->stat.considered++;
3502                         spin_unlock(&fs_info->balance_lock);
3503                 }
3504
3505                 ret = should_balance_chunk(chunk_root, leaf, chunk,
3506                                            found_key.offset);
3507
3508                 btrfs_release_path(path);
3509                 if (!ret) {
3510                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3511                         goto loop;
3512                 }
3513
3514                 if (counting) {
3515                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3516                         spin_lock(&fs_info->balance_lock);
3517                         bctl->stat.expected++;
3518                         spin_unlock(&fs_info->balance_lock);
3519
3520                         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3521                                 count_data++;
3522                         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3523                                 count_sys++;
3524                         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3525                                 count_meta++;
3526
3527                         goto loop;
3528                 }
3529
3530                 /*
3531                  * Apply limit_min filter, no need to check if the LIMITS
3532                  * filter is used, limit_min is 0 by default
3533                  */
3534                 if (((chunk_type & BTRFS_BLOCK_GROUP_DATA) &&
3535                                         count_data < bctl->data.limit_min)
3536                                 || ((chunk_type & BTRFS_BLOCK_GROUP_METADATA) &&
3537                                         count_meta < bctl->meta.limit_min)
3538                                 || ((chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) &&
3539                                         count_sys < bctl->sys.limit_min)) {
3540                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3541                         goto loop;
3542                 }
3543
3544                 if ((chunk_type & BTRFS_BLOCK_GROUP_DATA) && !chunk_reserved) {
3545                         trans = btrfs_start_transaction(chunk_root, 0);
3546                         if (IS_ERR(trans)) {
3547                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3548                                 ret = PTR_ERR(trans);
3549                                 goto error;
3550                         }
3551
3552                         ret = btrfs_force_chunk_alloc(trans, chunk_root,
3553                                                       BTRFS_BLOCK_GROUP_DATA);
3554                         btrfs_end_transaction(trans, chunk_root);
3555                         if (ret < 0) {
3556                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3557                                 goto error;
3558                         }
3559                         chunk_reserved = 1;
3560                 }
3561
3562                 ret = btrfs_relocate_chunk(chunk_root,
3563                                            found_key.offset);
3564                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3565                 if (ret && ret != -ENOSPC)
3566                         goto error;
3567                 if (ret == -ENOSPC) {
3568                         enospc_errors++;
3569                 } else {
3570                         spin_lock(&fs_info->balance_lock);
3571                         bctl->stat.completed++;
3572                         spin_unlock(&fs_info->balance_lock);
3573                 }
3574 loop:
3575                 if (found_key.offset == 0)
3576                         break;
3577                 key.offset = found_key.offset - 1;
3578         }
3579
3580         if (counting) {
3581                 btrfs_release_path(path);
3582                 counting = false;
3583                 goto again;
3584         }
3585 error:
3586         btrfs_free_path(path);
3587         if (enospc_errors) {
3588                 btrfs_info(fs_info, "%d enospc errors during balance",
3589                        enospc_errors);
3590                 if (!ret)
3591                         ret = -ENOSPC;
3592         }
3593
3594         return ret;
3595 }
3596
3597 /**
3598  * alloc_profile_is_valid - see if a given profile is valid and reduced
3599  * @flags: profile to validate
3600  * @extended: if true @flags is treated as an extended profile
3601  */
3602 static int alloc_profile_is_valid(u64 flags, int extended)
3603 {
3604         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
3605                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
3606
3607         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
3608
3609         /* 1) check that all other bits are zeroed */
3610         if (flags & ~mask)
3611                 return 0;
3612
3613         /* 2) see if profile is reduced */
3614         if (flags == 0)
3615                 return !extended; /* "0" is valid for usual profiles */
3616
3617         /* true if exactly one bit set */
3618         return (flags & (flags - 1)) == 0;
3619 }
3620
3621 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
3622 {
3623         /* cancel requested || normal exit path */
3624         return atomic_read(&fs_info->balance_cancel_req) ||
3625                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
3626                  atomic_read(&fs_info->balance_cancel_req) == 0);
3627 }
3628
3629 static void __cancel_balance(struct btrfs_fs_info *fs_info)
3630 {
3631         int ret;
3632
3633         unset_balance_control(fs_info);
3634         ret = del_balance_item(fs_info->tree_root);
3635         if (ret)
3636                 btrfs_std_error(fs_info, ret, NULL);
3637
3638         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3639 }
3640
3641 /* Non-zero return value signifies invalidity */
3642 static inline int validate_convert_profile(struct btrfs_balance_args *bctl_arg,
3643                 u64 allowed)
3644 {
3645         return ((bctl_arg->flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3646                 (!alloc_profile_is_valid(bctl_arg->target, 1) ||
3647                  (bctl_arg->target & ~allowed)));
3648 }
3649
3650 /*
3651  * Should be called with both balance and volume mutexes held
3652  */
3653 int btrfs_balance(struct btrfs_balance_control *bctl,
3654                   struct btrfs_ioctl_balance_args *bargs)
3655 {
3656         struct btrfs_fs_info *fs_info = bctl->fs_info;
3657         u64 allowed;
3658         int mixed = 0;
3659         int ret;
3660         u64 num_devices;
3661         unsigned seq;
3662
3663         if (btrfs_fs_closing(fs_info) ||
3664             atomic_read(&fs_info->balance_pause_req) ||
3665             atomic_read(&fs_info->balance_cancel_req)) {
3666                 ret = -EINVAL;
3667                 goto out;
3668         }
3669
3670         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
3671         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
3672                 mixed = 1;
3673
3674         /*
3675          * In case of mixed groups both data and meta should be picked,
3676          * and identical options should be given for both of them.
3677          */
3678         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
3679         if (mixed && (bctl->flags & allowed)) {
3680                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
3681                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
3682                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
3683                         btrfs_err(fs_info, "with mixed groups data and "
3684                                    "metadata balance options must be the same");
3685                         ret = -EINVAL;
3686                         goto out;
3687                 }
3688         }
3689
3690         num_devices = fs_info->fs_devices->num_devices;
3691         btrfs_dev_replace_lock(&fs_info->dev_replace);
3692         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3693                 BUG_ON(num_devices < 1);
3694                 num_devices--;
3695         }
3696         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3697         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3698         if (num_devices == 1)
3699                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3700         else if (num_devices > 1)
3701                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3702         if (num_devices > 2)
3703                 allowed |= BTRFS_BLOCK_GROUP_RAID5;
3704         if (num_devices > 3)
3705                 allowed |= (BTRFS_BLOCK_GROUP_RAID10 |
3706                             BTRFS_BLOCK_GROUP_RAID6);
3707         if (validate_convert_profile(&bctl->data, allowed)) {
3708                 btrfs_err(fs_info, "unable to start balance with target "
3709                            "data profile %llu",
3710                        bctl->data.target);
3711                 ret = -EINVAL;
3712                 goto out;
3713         }
3714         if (validate_convert_profile(&bctl->meta, allowed)) {
3715                 btrfs_err(fs_info,
3716                            "unable to start balance with target metadata profile %llu",
3717                        bctl->meta.target);
3718                 ret = -EINVAL;
3719                 goto out;
3720         }
3721         if (validate_convert_profile(&bctl->sys, allowed)) {
3722                 btrfs_err(fs_info,
3723                            "unable to start balance with target system profile %llu",
3724                        bctl->sys.target);
3725                 ret = -EINVAL;
3726                 goto out;
3727         }
3728
3729         /* allow dup'ed data chunks only in mixed mode */
3730         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3731             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
3732                 btrfs_err(fs_info, "dup for data is not allowed");
3733                 ret = -EINVAL;
3734                 goto out;
3735         }
3736
3737         /* allow to reduce meta or sys integrity only if force set */
3738         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3739                         BTRFS_BLOCK_GROUP_RAID10 |
3740                         BTRFS_BLOCK_GROUP_RAID5 |
3741                         BTRFS_BLOCK_GROUP_RAID6;
3742         do {
3743                 seq = read_seqbegin(&fs_info->profiles_lock);
3744
3745                 if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3746                      (fs_info->avail_system_alloc_bits & allowed) &&
3747                      !(bctl->sys.target & allowed)) ||
3748                     ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3749                      (fs_info->avail_metadata_alloc_bits & allowed) &&
3750                      !(bctl->meta.target & allowed))) {
3751                         if (bctl->flags & BTRFS_BALANCE_FORCE) {
3752                                 btrfs_info(fs_info, "force reducing metadata integrity");
3753                         } else {
3754                                 btrfs_err(fs_info, "balance will reduce metadata "
3755                                            "integrity, use force if you want this");
3756                                 ret = -EINVAL;
3757                                 goto out;
3758                         }
3759                 }
3760         } while (read_seqretry(&fs_info->profiles_lock, seq));
3761
3762         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3763                 fs_info->num_tolerated_disk_barrier_failures = min(
3764                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info),
3765                         btrfs_get_num_tolerated_disk_barrier_failures(
3766                                 bctl->sys.target));
3767         }
3768
3769         ret = insert_balance_item(fs_info->tree_root, bctl);
3770         if (ret && ret != -EEXIST)
3771                 goto out;
3772
3773         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3774                 BUG_ON(ret == -EEXIST);
3775                 set_balance_control(bctl);
3776         } else {
3777                 BUG_ON(ret != -EEXIST);
3778                 spin_lock(&fs_info->balance_lock);
3779                 update_balance_args(bctl);
3780                 spin_unlock(&fs_info->balance_lock);
3781         }
3782
3783         atomic_inc(&fs_info->balance_running);
3784         mutex_unlock(&fs_info->balance_mutex);
3785
3786         ret = __btrfs_balance(fs_info);
3787
3788         mutex_lock(&fs_info->balance_mutex);
3789         atomic_dec(&fs_info->balance_running);
3790
3791         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3792                 fs_info->num_tolerated_disk_barrier_failures =
3793                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3794         }
3795
3796         if (bargs) {
3797                 memset(bargs, 0, sizeof(*bargs));
3798                 update_ioctl_balance_args(fs_info, 0, bargs);
3799         }
3800
3801         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3802             balance_need_close(fs_info)) {
3803                 __cancel_balance(fs_info);
3804         }
3805
3806         wake_up(&fs_info->balance_wait_q);
3807
3808         return ret;
3809 out:
3810         if (bctl->flags & BTRFS_BALANCE_RESUME)
3811                 __cancel_balance(fs_info);
3812         else {
3813                 kfree(bctl);
3814                 atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3815         }
3816         return ret;
3817 }
3818
3819 static int balance_kthread(void *data)
3820 {
3821         struct btrfs_fs_info *fs_info = data;
3822         int ret = 0;
3823
3824         mutex_lock(&fs_info->volume_mutex);
3825         mutex_lock(&fs_info->balance_mutex);
3826
3827         if (fs_info->balance_ctl) {
3828                 btrfs_info(fs_info, "continuing balance");
3829                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3830         }
3831
3832         mutex_unlock(&fs_info->balance_mutex);
3833         mutex_unlock(&fs_info->volume_mutex);
3834
3835         return ret;
3836 }
3837
3838 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3839 {
3840         struct task_struct *tsk;
3841
3842         spin_lock(&fs_info->balance_lock);
3843         if (!fs_info->balance_ctl) {
3844                 spin_unlock(&fs_info->balance_lock);
3845                 return 0;
3846         }
3847         spin_unlock(&fs_info->balance_lock);
3848
3849         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3850                 btrfs_info(fs_info, "force skipping balance");
3851                 return 0;
3852         }
3853
3854         /*
3855          * A ro->rw remount sequence should continue with the paused balance
3856          * regardless of who pauses it, system or the user as of now, so set
3857          * the resume flag.
3858          */
3859         spin_lock(&fs_info->balance_lock);
3860         fs_info->balance_ctl->flags |= BTRFS_BALANCE_RESUME;
3861         spin_unlock(&fs_info->balance_lock);
3862
3863         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3864         return PTR_ERR_OR_ZERO(tsk);
3865 }
3866
3867 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3868 {
3869         struct btrfs_balance_control *bctl;
3870         struct btrfs_balance_item *item;
3871         struct btrfs_disk_balance_args disk_bargs;
3872         struct btrfs_path *path;
3873         struct extent_buffer *leaf;
3874         struct btrfs_key key;
3875         int ret;
3876
3877         path = btrfs_alloc_path();
3878         if (!path)
3879                 return -ENOMEM;
3880
3881         key.objectid = BTRFS_BALANCE_OBJECTID;
3882         key.type = BTRFS_BALANCE_ITEM_KEY;
3883         key.offset = 0;
3884
3885         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3886         if (ret < 0)
3887                 goto out;
3888         if (ret > 0) { /* ret = -ENOENT; */
3889                 ret = 0;
3890                 goto out;
3891         }
3892
3893         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3894         if (!bctl) {
3895                 ret = -ENOMEM;
3896                 goto out;
3897         }
3898
3899         leaf = path->nodes[0];
3900         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3901
3902         bctl->fs_info = fs_info;
3903         bctl->flags = btrfs_balance_flags(leaf, item);
3904         bctl->flags |= BTRFS_BALANCE_RESUME;
3905
3906         btrfs_balance_data(leaf, item, &disk_bargs);
3907         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3908         btrfs_balance_meta(leaf, item, &disk_bargs);
3909         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3910         btrfs_balance_sys(leaf, item, &disk_bargs);
3911         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3912
3913         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3914
3915         mutex_lock(&fs_info->volume_mutex);
3916         mutex_lock(&fs_info->balance_mutex);
3917
3918         set_balance_control(bctl);
3919
3920         mutex_unlock(&fs_info->balance_mutex);
3921         mutex_unlock(&fs_info->volume_mutex);
3922 out:
3923         btrfs_free_path(path);
3924         return ret;
3925 }
3926
3927 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3928 {
3929         int ret = 0;
3930
3931         mutex_lock(&fs_info->balance_mutex);
3932         if (!fs_info->balance_ctl) {
3933                 mutex_unlock(&fs_info->balance_mutex);
3934                 return -ENOTCONN;
3935         }
3936
3937         if (atomic_read(&fs_info->balance_running)) {
3938                 atomic_inc(&fs_info->balance_pause_req);
3939                 mutex_unlock(&fs_info->balance_mutex);
3940
3941                 wait_event(fs_info->balance_wait_q,
3942                            atomic_read(&fs_info->balance_running) == 0);
3943
3944                 mutex_lock(&fs_info->balance_mutex);
3945                 /* we are good with balance_ctl ripped off from under us */
3946                 BUG_ON(atomic_read(&fs_info->balance_running));
3947                 atomic_dec(&fs_info->balance_pause_req);
3948         } else {
3949                 ret = -ENOTCONN;
3950         }
3951
3952         mutex_unlock(&fs_info->balance_mutex);
3953         return ret;
3954 }
3955
3956 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3957 {
3958         if (fs_info->sb->s_flags & MS_RDONLY)
3959                 return -EROFS;
3960
3961         mutex_lock(&fs_info->balance_mutex);
3962         if (!fs_info->balance_ctl) {
3963                 mutex_unlock(&fs_info->balance_mutex);
3964                 return -ENOTCONN;
3965         }
3966
3967         atomic_inc(&fs_info->balance_cancel_req);
3968         /*
3969          * if we are running just wait and return, balance item is
3970          * deleted in btrfs_balance in this case
3971          */
3972         if (atomic_read(&fs_info->balance_running)) {
3973                 mutex_unlock(&fs_info->balance_mutex);
3974                 wait_event(fs_info->balance_wait_q,
3975                            atomic_read(&fs_info->balance_running) == 0);
3976                 mutex_lock(&fs_info->balance_mutex);
3977         } else {
3978                 /* __cancel_balance needs volume_mutex */
3979                 mutex_unlock(&fs_info->balance_mutex);
3980                 mutex_lock(&fs_info->volume_mutex);
3981                 mutex_lock(&fs_info->balance_mutex);
3982
3983                 if (fs_info->balance_ctl)
3984                         __cancel_balance(fs_info);
3985
3986                 mutex_unlock(&fs_info->volume_mutex);
3987         }
3988
3989         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3990         atomic_dec(&fs_info->balance_cancel_req);
3991         mutex_unlock(&fs_info->balance_mutex);
3992         return 0;
3993 }
3994
3995 static int btrfs_uuid_scan_kthread(void *data)
3996 {
3997         struct btrfs_fs_info *fs_info = data;
3998         struct btrfs_root *root = fs_info->tree_root;
3999         struct btrfs_key key;
4000         struct btrfs_key max_key;
4001         struct btrfs_path *path = NULL;
4002         int ret = 0;
4003         struct extent_buffer *eb;
4004         int slot;
4005         struct btrfs_root_item root_item;
4006         u32 item_size;
4007         struct btrfs_trans_handle *trans = NULL;
4008
4009         path = btrfs_alloc_path();
4010         if (!path) {
4011                 ret = -ENOMEM;
4012                 goto out;
4013         }
4014
4015         key.objectid = 0;
4016         key.type = BTRFS_ROOT_ITEM_KEY;
4017         key.offset = 0;
4018
4019         max_key.objectid = (u64)-1;
4020         max_key.type = BTRFS_ROOT_ITEM_KEY;
4021         max_key.offset = (u64)-1;
4022
4023         while (1) {
4024                 ret = btrfs_search_forward(root, &key, path, 0);
4025                 if (ret) {
4026                         if (ret > 0)
4027                                 ret = 0;
4028                         break;
4029                 }
4030
4031                 if (key.type != BTRFS_ROOT_ITEM_KEY ||
4032                     (key.objectid < BTRFS_FIRST_FREE_OBJECTID &&
4033                      key.objectid != BTRFS_FS_TREE_OBJECTID) ||
4034                     key.objectid > BTRFS_LAST_FREE_OBJECTID)
4035                         goto skip;
4036
4037                 eb = path->nodes[0];
4038                 slot = path->slots[0];
4039                 item_size = btrfs_item_size_nr(eb, slot);
4040                 if (item_size < sizeof(root_item))
4041                         goto skip;
4042
4043                 read_extent_buffer(eb, &root_item,
4044                                    btrfs_item_ptr_offset(eb, slot),
4045                                    (int)sizeof(root_item));
4046                 if (btrfs_root_refs(&root_item) == 0)
4047                         goto skip;
4048
4049                 if (!btrfs_is_empty_uuid(root_item.uuid) ||
4050                     !btrfs_is_empty_uuid(root_item.received_uuid)) {
4051                         if (trans)
4052                                 goto update_tree;
4053
4054                         btrfs_release_path(path);
4055                         /*
4056                          * 1 - subvol uuid item
4057                          * 1 - received_subvol uuid item
4058                          */
4059                         trans = btrfs_start_transaction(fs_info->uuid_root, 2);
4060                         if (IS_ERR(trans)) {
4061                                 ret = PTR_ERR(trans);
4062                                 break;
4063                         }
4064                         continue;
4065                 } else {
4066                         goto skip;
4067                 }
4068 update_tree:
4069                 btrfs_release_path(path);
4070                 if (!btrfs_is_empty_uuid(root_item.uuid)) {
4071                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
4072                                                   root_item.uuid,
4073                                                   BTRFS_UUID_KEY_SUBVOL,
4074                                                   key.objectid);
4075                         if (ret < 0) {
4076                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4077                                         ret);
4078                                 break;
4079                         }
4080                 }
4081
4082                 if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
4083                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
4084                                                   root_item.received_uuid,
4085                                                  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4086                                                   key.objectid);
4087                         if (ret < 0) {
4088                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4089                                         ret);
4090                                 break;
4091                         }
4092                 }
4093
4094 skip:
4095                 btrfs_release_path(path);
4096                 if (trans) {
4097                         ret = btrfs_end_transaction(trans, fs_info->uuid_root);
4098                         trans = NULL;
4099                         if (ret)
4100                                 break;
4101                 }
4102
4103                 if (key.offset < (u64)-1) {
4104                         key.offset++;
4105                 } else if (key.type < BTRFS_ROOT_ITEM_KEY) {
4106                         key.offset = 0;
4107                         key.type = BTRFS_ROOT_ITEM_KEY;
4108                 } else if (key.objectid < (u64)-1) {
4109                         key.offset = 0;
4110                         key.type = BTRFS_ROOT_ITEM_KEY;
4111                         key.objectid++;
4112                 } else {
4113                         break;
4114                 }
4115                 cond_resched();
4116         }
4117
4118 out:
4119         btrfs_free_path(path);
4120         if (trans && !IS_ERR(trans))
4121                 btrfs_end_transaction(trans, fs_info->uuid_root);
4122         if (ret)
4123                 btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
4124         else
4125                 fs_info->update_uuid_tree_gen = 1;
4126         up(&fs_info->uuid_tree_rescan_sem);
4127         return 0;
4128 }
4129
4130 /*
4131  * Callback for btrfs_uuid_tree_iterate().
4132  * returns:
4133  * 0    check succeeded, the entry is not outdated.
4134  * < 0  if an error occured.
4135  * > 0  if the check failed, which means the caller shall remove the entry.
4136  */
4137 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
4138                                        u8 *uuid, u8 type, u64 subid)
4139 {
4140         struct btrfs_key key;
4141         int ret = 0;
4142         struct btrfs_root *subvol_root;
4143
4144         if (type != BTRFS_UUID_KEY_SUBVOL &&
4145             type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
4146                 goto out;
4147
4148         key.objectid = subid;
4149         key.type = BTRFS_ROOT_ITEM_KEY;
4150         key.offset = (u64)-1;
4151         subvol_root = btrfs_read_fs_root_no_name(fs_info, &key);
4152         if (IS_ERR(subvol_root)) {
4153                 ret = PTR_ERR(subvol_root);
4154                 if (ret == -ENOENT)
4155                         ret = 1;
4156                 goto out;
4157         }
4158
4159         switch (type) {
4160         case BTRFS_UUID_KEY_SUBVOL:
4161                 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
4162                         ret = 1;
4163                 break;
4164         case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
4165                 if (memcmp(uuid, subvol_root->root_item.received_uuid,
4166                            BTRFS_UUID_SIZE))
4167                         ret = 1;
4168                 break;
4169         }
4170
4171 out:
4172         return ret;
4173 }
4174
4175 static int btrfs_uuid_rescan_kthread(void *data)
4176 {
4177         struct btrfs_fs_info *fs_info = (struct btrfs_fs_info *)data;
4178         int ret;
4179
4180         /*
4181          * 1st step is to iterate through the existing UUID tree and
4182          * to delete all entries that contain outdated data.
4183          * 2nd step is to add all missing entries to the UUID tree.
4184          */
4185         ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
4186         if (ret < 0) {
4187                 btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
4188                 up(&fs_info->uuid_tree_rescan_sem);
4189                 return ret;
4190         }
4191         return btrfs_uuid_scan_kthread(data);
4192 }
4193
4194 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
4195 {
4196         struct btrfs_trans_handle *trans;
4197         struct btrfs_root *tree_root = fs_info->tree_root;
4198         struct btrfs_root *uuid_root;
4199         struct task_struct *task;
4200         int ret;
4201
4202         /*
4203          * 1 - root node
4204          * 1 - root item
4205          */
4206         trans = btrfs_start_transaction(tree_root, 2);
4207         if (IS_ERR(trans))
4208                 return PTR_ERR(trans);
4209
4210         uuid_root = btrfs_create_tree(trans, fs_info,
4211                                       BTRFS_UUID_TREE_OBJECTID);
4212         if (IS_ERR(uuid_root)) {
4213                 ret = PTR_ERR(uuid_root);
4214                 btrfs_abort_transaction(trans, tree_root, ret);
4215                 return ret;
4216         }
4217
4218         fs_info->uuid_root = uuid_root;
4219
4220         ret = btrfs_commit_transaction(trans, tree_root);
4221         if (ret)
4222                 return ret;
4223
4224         down(&fs_info->uuid_tree_rescan_sem);
4225         task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
4226         if (IS_ERR(task)) {
4227                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4228                 btrfs_warn(fs_info, "failed to start uuid_scan task");
4229                 up(&fs_info->uuid_tree_rescan_sem);
4230                 return PTR_ERR(task);
4231         }
4232
4233         return 0;
4234 }
4235
4236 int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
4237 {
4238         struct task_struct *task;
4239
4240         down(&fs_info->uuid_tree_rescan_sem);
4241         task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
4242         if (IS_ERR(task)) {
4243                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4244                 btrfs_warn(fs_info, "failed to start uuid_rescan task");
4245                 up(&fs_info->uuid_tree_rescan_sem);
4246                 return PTR_ERR(task);
4247         }
4248
4249         return 0;
4250 }
4251
4252 /*
4253  * shrinking a device means finding all of the device extents past
4254  * the new size, and then following the back refs to the chunks.
4255  * The chunk relocation code actually frees the device extent
4256  */
4257 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
4258 {
4259         struct btrfs_trans_handle *trans;
4260         struct btrfs_root *root = device->dev_root;
4261         struct btrfs_dev_extent *dev_extent = NULL;
4262         struct btrfs_path *path;
4263         u64 length;
4264         u64 chunk_offset;
4265         int ret;
4266         int slot;
4267         int failed = 0;
4268         bool retried = false;
4269         bool checked_pending_chunks = false;
4270         struct extent_buffer *l;
4271         struct btrfs_key key;
4272         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4273         u64 old_total = btrfs_super_total_bytes(super_copy);
4274         u64 old_size = btrfs_device_get_total_bytes(device);
4275         u64 diff = old_size - new_size;
4276
4277         if (device->is_tgtdev_for_dev_replace)
4278                 return -EINVAL;
4279
4280         path = btrfs_alloc_path();
4281         if (!path)
4282                 return -ENOMEM;
4283
4284         path->reada = 2;
4285
4286         lock_chunks(root);
4287
4288         btrfs_device_set_total_bytes(device, new_size);
4289         if (device->writeable) {
4290                 device->fs_devices->total_rw_bytes -= diff;
4291                 spin_lock(&root->fs_info->free_chunk_lock);
4292                 root->fs_info->free_chunk_space -= diff;
4293                 spin_unlock(&root->fs_info->free_chunk_lock);
4294         }
4295         unlock_chunks(root);
4296
4297 again:
4298         key.objectid = device->devid;
4299         key.offset = (u64)-1;
4300         key.type = BTRFS_DEV_EXTENT_KEY;
4301
4302         do {
4303                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
4304                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4305                 if (ret < 0) {
4306                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4307                         goto done;
4308                 }
4309
4310                 ret = btrfs_previous_item(root, path, 0, key.type);
4311                 if (ret)
4312                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4313                 if (ret < 0)
4314                         goto done;
4315                 if (ret) {
4316                         ret = 0;
4317                         btrfs_release_path(path);
4318                         break;
4319                 }
4320
4321                 l = path->nodes[0];
4322                 slot = path->slots[0];
4323                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
4324
4325                 if (key.objectid != device->devid) {
4326                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4327                         btrfs_release_path(path);
4328                         break;
4329                 }
4330
4331                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
4332                 length = btrfs_dev_extent_length(l, dev_extent);
4333
4334                 if (key.offset + length <= new_size) {
4335                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4336                         btrfs_release_path(path);
4337                         break;
4338                 }
4339
4340                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
4341                 btrfs_release_path(path);
4342
4343                 ret = btrfs_relocate_chunk(root, chunk_offset);
4344                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4345                 if (ret && ret != -ENOSPC)
4346                         goto done;
4347                 if (ret == -ENOSPC)
4348                         failed++;
4349         } while (key.offset-- > 0);
4350
4351         if (failed && !retried) {
4352                 failed = 0;
4353                 retried = true;
4354                 goto again;
4355         } else if (failed && retried) {
4356                 ret = -ENOSPC;
4357                 goto done;
4358         }
4359
4360         /* Shrinking succeeded, else we would be at "done". */
4361         trans = btrfs_start_transaction(root, 0);
4362         if (IS_ERR(trans)) {
4363                 ret = PTR_ERR(trans);
4364                 goto done;
4365         }
4366
4367         lock_chunks(root);
4368
4369         /*
4370          * We checked in the above loop all device extents that were already in
4371          * the device tree. However before we have updated the device's
4372          * total_bytes to the new size, we might have had chunk allocations that
4373          * have not complete yet (new block groups attached to transaction
4374          * handles), and therefore their device extents were not yet in the
4375          * device tree and we missed them in the loop above. So if we have any
4376          * pending chunk using a device extent that overlaps the device range
4377          * that we can not use anymore, commit the current transaction and
4378          * repeat the search on the device tree - this way we guarantee we will
4379          * not have chunks using device extents that end beyond 'new_size'.
4380          */
4381         if (!checked_pending_chunks) {
4382                 u64 start = new_size;
4383                 u64 len = old_size - new_size;
4384
4385                 if (contains_pending_extent(trans->transaction, device,
4386                                             &start, len)) {
4387                         unlock_chunks(root);
4388                         checked_pending_chunks = true;
4389                         failed = 0;
4390                         retried = false;
4391                         ret = btrfs_commit_transaction(trans, root);
4392                         if (ret)
4393                                 goto done;
4394                         goto again;
4395                 }
4396         }
4397
4398         btrfs_device_set_disk_total_bytes(device, new_size);
4399         if (list_empty(&device->resized_list))
4400                 list_add_tail(&device->resized_list,
4401                               &root->fs_info->fs_devices->resized_devices);
4402
4403         WARN_ON(diff > old_total);
4404         btrfs_set_super_total_bytes(super_copy, old_total - diff);
4405         unlock_chunks(root);
4406
4407         /* Now btrfs_update_device() will change the on-disk size. */
4408         ret = btrfs_update_device(trans, device);
4409         btrfs_end_transaction(trans, root);
4410 done:
4411         btrfs_free_path(path);
4412         if (ret) {
4413                 lock_chunks(root);
4414                 btrfs_device_set_total_bytes(device, old_size);
4415                 if (device->writeable)
4416                         device->fs_devices->total_rw_bytes += diff;
4417                 spin_lock(&root->fs_info->free_chunk_lock);
4418                 root->fs_info->free_chunk_space += diff;
4419                 spin_unlock(&root->fs_info->free_chunk_lock);
4420                 unlock_chunks(root);
4421         }
4422         return ret;
4423 }
4424
4425 static int btrfs_add_system_chunk(struct btrfs_root *root,
4426                            struct btrfs_key *key,
4427                            struct btrfs_chunk *chunk, int item_size)
4428 {
4429         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4430         struct btrfs_disk_key disk_key;
4431         u32 array_size;
4432         u8 *ptr;
4433
4434         lock_chunks(root);
4435         array_size = btrfs_super_sys_array_size(super_copy);
4436         if (array_size + item_size + sizeof(disk_key)
4437                         > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
4438                 unlock_chunks(root);
4439                 return -EFBIG;
4440         }
4441
4442         ptr = super_copy->sys_chunk_array + array_size;
4443         btrfs_cpu_key_to_disk(&disk_key, key);
4444         memcpy(ptr, &disk_key, sizeof(disk_key));
4445         ptr += sizeof(disk_key);
4446         memcpy(ptr, chunk, item_size);
4447         item_size += sizeof(disk_key);
4448         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
4449         unlock_chunks(root);
4450
4451         return 0;
4452 }
4453
4454 /*
4455  * sort the devices in descending order by max_avail, total_avail
4456  */
4457 static int btrfs_cmp_device_info(const void *a, const void *b)
4458 {
4459         const struct btrfs_device_info *di_a = a;
4460         const struct btrfs_device_info *di_b = b;
4461
4462         if (di_a->max_avail > di_b->max_avail)
4463                 return -1;
4464         if (di_a->max_avail < di_b->max_avail)
4465                 return 1;
4466         if (di_a->total_avail > di_b->total_avail)
4467                 return -1;
4468         if (di_a->total_avail < di_b->total_avail)
4469                 return 1;
4470         return 0;
4471 }
4472
4473 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
4474 {
4475         /* TODO allow them to set a preferred stripe size */
4476         return 64 * 1024;
4477 }
4478
4479 static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
4480 {
4481         if (!(type & BTRFS_BLOCK_GROUP_RAID56_MASK))
4482                 return;
4483
4484         btrfs_set_fs_incompat(info, RAID56);
4485 }
4486
4487 #define BTRFS_MAX_DEVS(r) ((BTRFS_LEAF_DATA_SIZE(r)             \
4488                         - sizeof(struct btrfs_item)             \
4489                         - sizeof(struct btrfs_chunk))           \
4490                         / sizeof(struct btrfs_stripe) + 1)
4491
4492 #define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE        \
4493                                 - 2 * sizeof(struct btrfs_disk_key)     \
4494                                 - 2 * sizeof(struct btrfs_chunk))       \
4495                                 / sizeof(struct btrfs_stripe) + 1)
4496
4497 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4498                                struct btrfs_root *extent_root, u64 start,
4499                                u64 type)
4500 {
4501         struct btrfs_fs_info *info = extent_root->fs_info;
4502         struct btrfs_fs_devices *fs_devices = info->fs_devices;
4503         struct list_head *cur;
4504         struct map_lookup *map = NULL;
4505         struct extent_map_tree *em_tree;
4506         struct extent_map *em;
4507         struct btrfs_device_info *devices_info = NULL;
4508         u64 total_avail;
4509         int num_stripes;        /* total number of stripes to allocate */
4510         int data_stripes;       /* number of stripes that count for
4511                                    block group size */
4512         int sub_stripes;        /* sub_stripes info for map */
4513         int dev_stripes;        /* stripes per dev */
4514         int devs_max;           /* max devs to use */
4515         int devs_min;           /* min devs needed */
4516         int devs_increment;     /* ndevs has to be a multiple of this */
4517         int ncopies;            /* how many copies to data has */
4518         int ret;
4519         u64 max_stripe_size;
4520         u64 max_chunk_size;
4521         u64 stripe_size;
4522         u64 num_bytes;
4523         u64 raid_stripe_len = BTRFS_STRIPE_LEN;
4524         int ndevs;
4525         int i;
4526         int j;
4527         int index;
4528
4529         BUG_ON(!alloc_profile_is_valid(type, 0));
4530
4531         if (list_empty(&fs_devices->alloc_list))
4532                 return -ENOSPC;
4533
4534         index = __get_raid_index(type);
4535
4536         sub_stripes = btrfs_raid_array[index].sub_stripes;
4537         dev_stripes = btrfs_raid_array[index].dev_stripes;
4538         devs_max = btrfs_raid_array[index].devs_max;
4539         devs_min = btrfs_raid_array[index].devs_min;
4540         devs_increment = btrfs_raid_array[index].devs_increment;
4541         ncopies = btrfs_raid_array[index].ncopies;
4542
4543         if (type & BTRFS_BLOCK_GROUP_DATA) {
4544                 max_stripe_size = 1024 * 1024 * 1024;
4545                 max_chunk_size = BTRFS_MAX_DATA_CHUNK_SIZE;
4546                 if (!devs_max)
4547                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4548         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
4549                 /* for larger filesystems, use larger metadata chunks */
4550                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
4551                         max_stripe_size = 1024 * 1024 * 1024;
4552                 else
4553                         max_stripe_size = 256 * 1024 * 1024;
4554                 max_chunk_size = max_stripe_size;
4555                 if (!devs_max)
4556                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4557         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
4558                 max_stripe_size = 32 * 1024 * 1024;
4559                 max_chunk_size = 2 * max_stripe_size;
4560                 if (!devs_max)
4561                         devs_max = BTRFS_MAX_DEVS_SYS_CHUNK;
4562         } else {
4563                 btrfs_err(info, "invalid chunk type 0x%llx requested",
4564                        type);
4565                 BUG_ON(1);
4566         }
4567
4568         /* we don't want a chunk larger than 10% of writeable space */
4569         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
4570                              max_chunk_size);
4571
4572         devices_info = kcalloc(fs_devices->rw_devices, sizeof(*devices_info),
4573                                GFP_NOFS);
4574         if (!devices_info)
4575                 return -ENOMEM;
4576
4577         cur = fs_devices->alloc_list.next;
4578
4579         /*
4580          * in the first pass through the devices list, we gather information
4581          * about the available holes on each device.
4582          */
4583         ndevs = 0;
4584         while (cur != &fs_devices->alloc_list) {
4585                 struct btrfs_device *device;
4586                 u64 max_avail;
4587                 u64 dev_offset;
4588
4589                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
4590
4591                 cur = cur->next;
4592
4593                 if (!device->writeable) {
4594                         WARN(1, KERN_ERR
4595                                "BTRFS: read-only device in alloc_list\n");
4596                         continue;
4597                 }
4598
4599                 if (!device->in_fs_metadata ||
4600                     device->is_tgtdev_for_dev_replace)
4601                         continue;
4602
4603                 if (device->total_bytes > device->bytes_used)
4604                         total_avail = device->total_bytes - device->bytes_used;
4605                 else
4606                         total_avail = 0;
4607
4608                 /* If there is no space on this device, skip it. */
4609                 if (total_avail == 0)
4610                         continue;
4611
4612                 ret = find_free_dev_extent(trans, device,
4613                                            max_stripe_size * dev_stripes,
4614                                            &dev_offset, &max_avail);
4615                 if (ret && ret != -ENOSPC)
4616                         goto error;
4617
4618                 if (ret == 0)
4619                         max_avail = max_stripe_size * dev_stripes;
4620
4621                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
4622                         continue;
4623
4624                 if (ndevs == fs_devices->rw_devices) {
4625                         WARN(1, "%s: found more than %llu devices\n",
4626                              __func__, fs_devices->rw_devices);
4627                         break;
4628                 }
4629                 devices_info[ndevs].dev_offset = dev_offset;
4630                 devices_info[ndevs].max_avail = max_avail;
4631                 devices_info[ndevs].total_avail = total_avail;
4632                 devices_info[ndevs].dev = device;
4633                 ++ndevs;
4634         }
4635
4636         /*
4637          * now sort the devices by hole size / available space
4638          */
4639         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
4640              btrfs_cmp_device_info, NULL);
4641
4642         /* round down to number of usable stripes */
4643         ndevs -= ndevs % devs_increment;
4644
4645         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
4646                 ret = -ENOSPC;
4647                 goto error;
4648         }
4649
4650         if (devs_max && ndevs > devs_max)
4651                 ndevs = devs_max;
4652         /*
4653          * The primary goal is to maximize the number of stripes, so use as
4654          * many devices as possible, even if the stripes are not maximum sized.
4655          *
4656          * The DUP profile stores more than one stripe per device, the
4657          * max_avail is the total size so we have to adjust.
4658          */
4659         stripe_size = div_u64(devices_info[ndevs - 1].max_avail, dev_stripes);
4660         num_stripes = ndevs * dev_stripes;
4661
4662         /*
4663          * this will have to be fixed for RAID1 and RAID10 over
4664          * more drives
4665          */
4666         data_stripes = num_stripes / ncopies;
4667
4668         if (type & BTRFS_BLOCK_GROUP_RAID5) {
4669                 raid_stripe_len = find_raid56_stripe_len(ndevs - 1,
4670                                  btrfs_super_stripesize(info->super_copy));
4671                 data_stripes = num_stripes - 1;
4672         }
4673         if (type & BTRFS_BLOCK_GROUP_RAID6) {
4674                 raid_stripe_len = find_raid56_stripe_len(ndevs - 2,
4675                                  btrfs_super_stripesize(info->super_copy));
4676                 data_stripes = num_stripes - 2;
4677         }
4678
4679         /*
4680          * Use the number of data stripes to figure out how big this chunk
4681          * is really going to be in terms of logical address space,
4682          * and compare that answer with the max chunk size
4683          */
4684         if (stripe_size * data_stripes > max_chunk_size) {
4685                 u64 mask = (1ULL << 24) - 1;
4686
4687                 stripe_size = div_u64(max_chunk_size, data_stripes);
4688
4689                 /* bump the answer up to a 16MB boundary */
4690                 stripe_size = (stripe_size + mask) & ~mask;
4691
4692                 /* but don't go higher than the limits we found
4693                  * while searching for free extents
4694                  */
4695                 if (stripe_size > devices_info[ndevs-1].max_avail)
4696                         stripe_size = devices_info[ndevs-1].max_avail;
4697         }
4698
4699         /* align to BTRFS_STRIPE_LEN */
4700         stripe_size = div_u64(stripe_size, raid_stripe_len);
4701         stripe_size *= raid_stripe_len;
4702
4703         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4704         if (!map) {
4705                 ret = -ENOMEM;
4706                 goto error;
4707         }
4708         map->num_stripes = num_stripes;
4709
4710         for (i = 0; i < ndevs; ++i) {
4711                 for (j = 0; j < dev_stripes; ++j) {
4712                         int s = i * dev_stripes + j;
4713                         map->stripes[s].dev = devices_info[i].dev;
4714                         map->stripes[s].physical = devices_info[i].dev_offset +
4715                                                    j * stripe_size;
4716                 }
4717         }
4718         map->sector_size = extent_root->sectorsize;
4719         map->stripe_len = raid_stripe_len;
4720         map->io_align = raid_stripe_len;
4721         map->io_width = raid_stripe_len;
4722         map->type = type;
4723         map->sub_stripes = sub_stripes;
4724
4725         num_bytes = stripe_size * data_stripes;
4726
4727         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
4728
4729         em = alloc_extent_map();
4730         if (!em) {
4731                 kfree(map);
4732                 ret = -ENOMEM;
4733                 goto error;
4734         }
4735         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
4736         em->map_lookup = map;
4737         em->start = start;
4738         em->len = num_bytes;
4739         em->block_start = 0;
4740         em->block_len = em->len;
4741         em->orig_block_len = stripe_size;
4742
4743         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4744         write_lock(&em_tree->lock);
4745         ret = add_extent_mapping(em_tree, em, 0);
4746         if (!ret) {
4747                 list_add_tail(&em->list, &trans->transaction->pending_chunks);
4748                 atomic_inc(&em->refs);
4749         }
4750         write_unlock(&em_tree->lock);
4751         if (ret) {
4752                 free_extent_map(em);
4753                 goto error;
4754         }
4755
4756         ret = btrfs_make_block_group(trans, extent_root, 0, type,
4757                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4758                                      start, num_bytes);
4759         if (ret)
4760                 goto error_del_extent;
4761
4762         for (i = 0; i < map->num_stripes; i++) {
4763                 num_bytes = map->stripes[i].dev->bytes_used + stripe_size;
4764                 btrfs_device_set_bytes_used(map->stripes[i].dev, num_bytes);
4765                 map->stripes[i].dev->has_pending_chunks = true;
4766         }
4767
4768         spin_lock(&extent_root->fs_info->free_chunk_lock);
4769         extent_root->fs_info->free_chunk_space -= (stripe_size *
4770                                                    map->num_stripes);
4771         spin_unlock(&extent_root->fs_info->free_chunk_lock);
4772
4773         free_extent_map(em);
4774         check_raid56_incompat_flag(extent_root->fs_info, type);
4775
4776         kfree(devices_info);
4777         return 0;
4778
4779 error_del_extent:
4780         write_lock(&em_tree->lock);
4781         remove_extent_mapping(em_tree, em);
4782         write_unlock(&em_tree->lock);
4783
4784         /* One for our allocation */
4785         free_extent_map(em);
4786         /* One for the tree reference */
4787         free_extent_map(em);
4788         /* One for the pending_chunks list reference */
4789         free_extent_map(em);
4790 error:
4791         kfree(devices_info);
4792         return ret;
4793 }
4794
4795 int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
4796                                 struct btrfs_root *extent_root,
4797                                 u64 chunk_offset, u64 chunk_size)
4798 {
4799         struct btrfs_key key;
4800         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
4801         struct btrfs_device *device;
4802         struct btrfs_chunk *chunk;
4803         struct btrfs_stripe *stripe;
4804         struct extent_map_tree *em_tree;
4805         struct extent_map *em;
4806         struct map_lookup *map;
4807         size_t item_size;
4808         u64 dev_offset;
4809         u64 stripe_size;
4810         int i = 0;
4811         int ret;
4812
4813         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4814         read_lock(&em_tree->lock);
4815         em = lookup_extent_mapping(em_tree, chunk_offset, chunk_size);
4816         read_unlock(&em_tree->lock);
4817
4818         if (!em) {
4819                 btrfs_crit(extent_root->fs_info, "unable to find logical "
4820                            "%Lu len %Lu", chunk_offset, chunk_size);
4821                 return -EINVAL;
4822         }
4823
4824         if (em->start != chunk_offset || em->len != chunk_size) {
4825                 btrfs_crit(extent_root->fs_info, "found a bad mapping, wanted"
4826                           " %Lu-%Lu, found %Lu-%Lu", chunk_offset,
4827                           chunk_size, em->start, em->len);
4828                 free_extent_map(em);
4829                 return -EINVAL;
4830         }
4831
4832         map = em->map_lookup;
4833         item_size = btrfs_chunk_item_size(map->num_stripes);
4834         stripe_size = em->orig_block_len;
4835
4836         chunk = kzalloc(item_size, GFP_NOFS);
4837         if (!chunk) {
4838                 ret = -ENOMEM;
4839                 goto out;
4840         }
4841
4842         for (i = 0; i < map->num_stripes; i++) {
4843                 device = map->stripes[i].dev;
4844                 dev_offset = map->stripes[i].physical;
4845
4846                 ret = btrfs_update_device(trans, device);
4847                 if (ret)
4848                         goto out;
4849                 ret = btrfs_alloc_dev_extent(trans, device,
4850                                              chunk_root->root_key.objectid,
4851                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4852                                              chunk_offset, dev_offset,
4853                                              stripe_size);
4854                 if (ret)
4855                         goto out;
4856         }
4857
4858         stripe = &chunk->stripe;
4859         for (i = 0; i < map->num_stripes; i++) {
4860                 device = map->stripes[i].dev;
4861                 dev_offset = map->stripes[i].physical;
4862
4863                 btrfs_set_stack_stripe_devid(stripe, device->devid);
4864                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
4865                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
4866                 stripe++;
4867         }
4868
4869         btrfs_set_stack_chunk_length(chunk, chunk_size);
4870         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
4871         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
4872         btrfs_set_stack_chunk_type(chunk, map->type);
4873         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
4874         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
4875         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
4876         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
4877         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
4878
4879         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
4880         key.type = BTRFS_CHUNK_ITEM_KEY;
4881         key.offset = chunk_offset;
4882
4883         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
4884         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
4885                 /*
4886                  * TODO: Cleanup of inserted chunk root in case of
4887                  * failure.
4888                  */
4889                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
4890                                              item_size);
4891         }
4892
4893 out:
4894         kfree(chunk);
4895         free_extent_map(em);
4896         return ret;
4897 }
4898
4899 /*
4900  * Chunk allocation falls into two parts. The first part does works
4901  * that make the new allocated chunk useable, but not do any operation
4902  * that modifies the chunk tree. The second part does the works that
4903  * require modifying the chunk tree. This division is important for the
4904  * bootstrap process of adding storage to a seed btrfs.
4905  */
4906 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4907                       struct btrfs_root *extent_root, u64 type)
4908 {
4909         u64 chunk_offset;
4910
4911         ASSERT(mutex_is_locked(&extent_root->fs_info->chunk_mutex));
4912         chunk_offset = find_next_chunk(extent_root->fs_info);
4913         return __btrfs_alloc_chunk(trans, extent_root, chunk_offset, type);
4914 }
4915
4916 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
4917                                          struct btrfs_root *root,
4918                                          struct btrfs_device *device)
4919 {
4920         u64 chunk_offset;
4921         u64 sys_chunk_offset;
4922         u64 alloc_profile;
4923         struct btrfs_fs_info *fs_info = root->fs_info;
4924         struct btrfs_root *extent_root = fs_info->extent_root;
4925         int ret;
4926
4927         chunk_offset = find_next_chunk(fs_info);
4928         alloc_profile = btrfs_get_alloc_profile(extent_root, 0);
4929         ret = __btrfs_alloc_chunk(trans, extent_root, chunk_offset,
4930                                   alloc_profile);
4931         if (ret)
4932                 return ret;
4933
4934         sys_chunk_offset = find_next_chunk(root->fs_info);
4935         alloc_profile = btrfs_get_alloc_profile(fs_info->chunk_root, 0);
4936         ret = __btrfs_alloc_chunk(trans, extent_root, sys_chunk_offset,
4937                                   alloc_profile);
4938         return ret;
4939 }
4940
4941 static inline int btrfs_chunk_max_errors(struct map_lookup *map)
4942 {
4943         int max_errors;
4944
4945         if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4946                          BTRFS_BLOCK_GROUP_RAID10 |
4947                          BTRFS_BLOCK_GROUP_RAID5)) {
4948                 max_errors = 1;
4949         } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) {
4950                 max_errors = 2;
4951         } else {
4952                 max_errors = 0;
4953         }
4954
4955         return max_errors;
4956 }
4957
4958 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
4959 {
4960         struct extent_map *em;
4961         struct map_lookup *map;
4962         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4963         int readonly = 0;
4964         int miss_ndevs = 0;
4965         int i;
4966
4967         read_lock(&map_tree->map_tree.lock);
4968         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
4969         read_unlock(&map_tree->map_tree.lock);
4970         if (!em)
4971                 return 1;
4972
4973         map = em->map_lookup;
4974         for (i = 0; i < map->num_stripes; i++) {
4975                 if (map->stripes[i].dev->missing) {
4976                         miss_ndevs++;
4977                         continue;
4978                 }
4979
4980                 if (!map->stripes[i].dev->writeable) {
4981                         readonly = 1;
4982                         goto end;
4983                 }
4984         }
4985
4986         /*
4987          * If the number of missing devices is larger than max errors,
4988          * we can not write the data into that chunk successfully, so
4989          * set it readonly.
4990          */
4991         if (miss_ndevs > btrfs_chunk_max_errors(map))
4992                 readonly = 1;
4993 end:
4994         free_extent_map(em);
4995         return readonly;
4996 }
4997
4998 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
4999 {
5000         extent_map_tree_init(&tree->map_tree);
5001 }
5002
5003 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
5004 {
5005         struct extent_map *em;
5006
5007         while (1) {
5008                 write_lock(&tree->map_tree.lock);
5009                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
5010                 if (em)
5011                         remove_extent_mapping(&tree->map_tree, em);
5012                 write_unlock(&tree->map_tree.lock);
5013                 if (!em)
5014                         break;
5015                 /* once for us */
5016                 free_extent_map(em);
5017                 /* once for the tree */
5018                 free_extent_map(em);
5019         }
5020 }
5021
5022 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
5023 {
5024         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
5025         struct extent_map *em;
5026         struct map_lookup *map;
5027         struct extent_map_tree *em_tree = &map_tree->map_tree;
5028         int ret;
5029
5030         read_lock(&em_tree->lock);
5031         em = lookup_extent_mapping(em_tree, logical, len);
5032         read_unlock(&em_tree->lock);
5033
5034         /*
5035          * We could return errors for these cases, but that could get ugly and
5036          * we'd probably do the same thing which is just not do anything else
5037          * and exit, so return 1 so the callers don't try to use other copies.
5038          */
5039         if (!em) {
5040                 btrfs_crit(fs_info, "No mapping for %Lu-%Lu", logical,
5041                             logical+len);
5042                 return 1;
5043         }
5044
5045         if (em->start > logical || em->start + em->len < logical) {
5046                 btrfs_crit(fs_info, "Invalid mapping for %Lu-%Lu, got "
5047                             "%Lu-%Lu", logical, logical+len, em->start,
5048                             em->start + em->len);
5049                 free_extent_map(em);
5050                 return 1;
5051         }
5052
5053         map = em->map_lookup;
5054         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
5055                 ret = map->num_stripes;
5056         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5057                 ret = map->sub_stripes;
5058         else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
5059                 ret = 2;
5060         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5061                 /*
5062                  * There could be two corrupted data stripes, we need
5063                  * to loop retry in order to rebuild the correct data.
5064                  *
5065                  * Fail a stripe at a time on every retry except the
5066                  * stripe under reconstruction.
5067                  */
5068                 ret = map->num_stripes;
5069         else
5070                 ret = 1;
5071         free_extent_map(em);
5072
5073         btrfs_dev_replace_lock(&fs_info->dev_replace);
5074         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
5075                 ret++;
5076         btrfs_dev_replace_unlock(&fs_info->dev_replace);
5077
5078         return ret;
5079 }
5080
5081 unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
5082                                     struct btrfs_mapping_tree *map_tree,
5083                                     u64 logical)
5084 {
5085         struct extent_map *em;
5086         struct map_lookup *map;
5087         struct extent_map_tree *em_tree = &map_tree->map_tree;
5088         unsigned long len = root->sectorsize;
5089
5090         read_lock(&em_tree->lock);
5091         em = lookup_extent_mapping(em_tree, logical, len);
5092         read_unlock(&em_tree->lock);
5093         BUG_ON(!em);
5094
5095         BUG_ON(em->start > logical || em->start + em->len < logical);
5096         map = em->map_lookup;
5097         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5098                 len = map->stripe_len * nr_data_stripes(map);
5099         free_extent_map(em);
5100         return len;
5101 }
5102
5103 int btrfs_is_parity_mirror(struct btrfs_mapping_tree *map_tree,
5104                            u64 logical, u64 len, int mirror_num)
5105 {
5106         struct extent_map *em;
5107         struct map_lookup *map;
5108         struct extent_map_tree *em_tree = &map_tree->map_tree;
5109         int ret = 0;
5110
5111         read_lock(&em_tree->lock);
5112         em = lookup_extent_mapping(em_tree, logical, len);
5113         read_unlock(&em_tree->lock);
5114         BUG_ON(!em);
5115
5116         BUG_ON(em->start > logical || em->start + em->len < logical);
5117         map = em->map_lookup;
5118         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5119                 ret = 1;
5120         free_extent_map(em);
5121         return ret;
5122 }
5123
5124 static int find_live_mirror(struct btrfs_fs_info *fs_info,
5125                             struct map_lookup *map, int first, int num,
5126                             int optimal, int dev_replace_is_ongoing)
5127 {
5128         int i;
5129         int tolerance;
5130         struct btrfs_device *srcdev;
5131
5132         if (dev_replace_is_ongoing &&
5133             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
5134              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
5135                 srcdev = fs_info->dev_replace.srcdev;
5136         else
5137                 srcdev = NULL;
5138
5139         /*
5140          * try to avoid the drive that is the source drive for a
5141          * dev-replace procedure, only choose it if no other non-missing
5142          * mirror is available
5143          */
5144         for (tolerance = 0; tolerance < 2; tolerance++) {
5145                 if (map->stripes[optimal].dev->bdev &&
5146                     (tolerance || map->stripes[optimal].dev != srcdev))
5147                         return optimal;
5148                 for (i = first; i < first + num; i++) {
5149                         if (map->stripes[i].dev->bdev &&
5150                             (tolerance || map->stripes[i].dev != srcdev))
5151                                 return i;
5152                 }
5153         }
5154
5155         /* we couldn't find one that doesn't fail.  Just return something
5156          * and the io error handling code will clean up eventually
5157          */
5158         return optimal;
5159 }
5160
5161 static inline int parity_smaller(u64 a, u64 b)
5162 {
5163         return a > b;
5164 }
5165
5166 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
5167 static void sort_parity_stripes(struct btrfs_bio *bbio, int num_stripes)
5168 {
5169         struct btrfs_bio_stripe s;
5170         int i;
5171         u64 l;
5172         int again = 1;
5173
5174         while (again) {
5175                 again = 0;
5176                 for (i = 0; i < num_stripes - 1; i++) {
5177                         if (parity_smaller(bbio->raid_map[i],
5178                                            bbio->raid_map[i+1])) {
5179                                 s = bbio->stripes[i];
5180                                 l = bbio->raid_map[i];
5181                                 bbio->stripes[i] = bbio->stripes[i+1];
5182                                 bbio->raid_map[i] = bbio->raid_map[i+1];
5183                                 bbio->stripes[i+1] = s;
5184                                 bbio->raid_map[i+1] = l;
5185
5186                                 again = 1;
5187                         }
5188                 }
5189         }
5190 }
5191
5192 static struct btrfs_bio *alloc_btrfs_bio(int total_stripes, int real_stripes)
5193 {
5194         struct btrfs_bio *bbio = kzalloc(
5195                  /* the size of the btrfs_bio */
5196                 sizeof(struct btrfs_bio) +
5197                 /* plus the variable array for the stripes */
5198                 sizeof(struct btrfs_bio_stripe) * (total_stripes) +
5199                 /* plus the variable array for the tgt dev */
5200                 sizeof(int) * (real_stripes) +
5201                 /*
5202                  * plus the raid_map, which includes both the tgt dev
5203                  * and the stripes
5204                  */
5205                 sizeof(u64) * (total_stripes),
5206                 GFP_NOFS|__GFP_NOFAIL);
5207
5208         atomic_set(&bbio->error, 0);
5209         atomic_set(&bbio->refs, 1);
5210
5211         return bbio;
5212 }
5213
5214 void btrfs_get_bbio(struct btrfs_bio *bbio)
5215 {
5216         WARN_ON(!atomic_read(&bbio->refs));
5217         atomic_inc(&bbio->refs);
5218 }
5219
5220 void btrfs_put_bbio(struct btrfs_bio *bbio)
5221 {
5222         if (!bbio)
5223                 return;
5224         if (atomic_dec_and_test(&bbio->refs))
5225                 kfree(bbio);
5226 }
5227
5228 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5229                              u64 logical, u64 *length,
5230                              struct btrfs_bio **bbio_ret,
5231                              int mirror_num, int need_raid_map)
5232 {
5233         struct extent_map *em;
5234         struct map_lookup *map;
5235         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
5236         struct extent_map_tree *em_tree = &map_tree->map_tree;
5237         u64 offset;
5238         u64 stripe_offset;
5239         u64 stripe_end_offset;
5240         u64 stripe_nr;
5241         u64 stripe_nr_orig;
5242         u64 stripe_nr_end;
5243         u64 stripe_len;
5244         u32 stripe_index;
5245         int i;
5246         int ret = 0;
5247         int num_stripes;
5248         int max_errors = 0;
5249         int tgtdev_indexes = 0;
5250         struct btrfs_bio *bbio = NULL;
5251         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
5252         int dev_replace_is_ongoing = 0;
5253         int num_alloc_stripes;
5254         int patch_the_first_stripe_for_dev_replace = 0;
5255         u64 physical_to_patch_in_first_stripe = 0;
5256         u64 raid56_full_stripe_start = (u64)-1;
5257
5258         read_lock(&em_tree->lock);
5259         em = lookup_extent_mapping(em_tree, logical, *length);
5260         read_unlock(&em_tree->lock);
5261
5262         if (!em) {
5263                 btrfs_crit(fs_info, "unable to find logical %llu len %llu",
5264                         logical, *length);
5265                 return -EINVAL;
5266         }
5267
5268         if (em->start > logical || em->start + em->len < logical) {
5269                 btrfs_crit(fs_info, "found a bad mapping, wanted %Lu, "
5270                            "found %Lu-%Lu", logical, em->start,
5271                            em->start + em->len);
5272                 free_extent_map(em);
5273                 return -EINVAL;
5274         }
5275
5276         map = em->map_lookup;
5277         offset = logical - em->start;
5278
5279         stripe_len = map->stripe_len;
5280         stripe_nr = offset;
5281         /*
5282          * stripe_nr counts the total number of stripes we have to stride
5283          * to get to this block
5284          */
5285         stripe_nr = div64_u64(stripe_nr, stripe_len);
5286
5287         stripe_offset = stripe_nr * stripe_len;
5288         BUG_ON(offset < stripe_offset);
5289
5290         /* stripe_offset is the offset of this block in its stripe*/
5291         stripe_offset = offset - stripe_offset;
5292
5293         /* if we're here for raid56, we need to know the stripe aligned start */
5294         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5295                 unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
5296                 raid56_full_stripe_start = offset;
5297
5298                 /* allow a write of a full stripe, but make sure we don't
5299                  * allow straddling of stripes
5300                  */
5301                 raid56_full_stripe_start = div64_u64(raid56_full_stripe_start,
5302                                 full_stripe_len);
5303                 raid56_full_stripe_start *= full_stripe_len;
5304         }
5305
5306         if (rw & REQ_DISCARD) {
5307                 /* we don't discard raid56 yet */
5308                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5309                         ret = -EOPNOTSUPP;
5310                         goto out;
5311                 }
5312                 *length = min_t(u64, em->len - offset, *length);
5313         } else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
5314                 u64 max_len;
5315                 /* For writes to RAID[56], allow a full stripeset across all disks.
5316                    For other RAID types and for RAID[56] reads, just allow a single
5317                    stripe (on a single disk). */
5318                 if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
5319                     (rw & REQ_WRITE)) {
5320                         max_len = stripe_len * nr_data_stripes(map) -
5321                                 (offset - raid56_full_stripe_start);
5322                 } else {
5323                         /* we limit the length of each bio to what fits in a stripe */
5324                         max_len = stripe_len - stripe_offset;
5325                 }
5326                 *length = min_t(u64, em->len - offset, max_len);
5327         } else {
5328                 *length = em->len - offset;
5329         }
5330
5331         /* This is for when we're called from btrfs_merge_bio_hook() and all
5332            it cares about is the length */
5333         if (!bbio_ret)
5334                 goto out;
5335
5336         btrfs_dev_replace_lock(dev_replace);
5337         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
5338         if (!dev_replace_is_ongoing)
5339                 btrfs_dev_replace_unlock(dev_replace);
5340
5341         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
5342             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
5343             dev_replace->tgtdev != NULL) {
5344                 /*
5345                  * in dev-replace case, for repair case (that's the only
5346                  * case where the mirror is selected explicitly when
5347                  * calling btrfs_map_block), blocks left of the left cursor
5348                  * can also be read from the target drive.
5349                  * For REQ_GET_READ_MIRRORS, the target drive is added as
5350                  * the last one to the array of stripes. For READ, it also
5351                  * needs to be supported using the same mirror number.
5352                  * If the requested block is not left of the left cursor,
5353                  * EIO is returned. This can happen because btrfs_num_copies()
5354                  * returns one more in the dev-replace case.
5355                  */
5356                 u64 tmp_length = *length;
5357                 struct btrfs_bio *tmp_bbio = NULL;
5358                 int tmp_num_stripes;
5359                 u64 srcdev_devid = dev_replace->srcdev->devid;
5360                 int index_srcdev = 0;
5361                 int found = 0;
5362                 u64 physical_of_found = 0;
5363
5364                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
5365                              logical, &tmp_length, &tmp_bbio, 0, 0);
5366                 if (ret) {
5367                         WARN_ON(tmp_bbio != NULL);
5368                         goto out;
5369                 }
5370
5371                 tmp_num_stripes = tmp_bbio->num_stripes;
5372                 if (mirror_num > tmp_num_stripes) {
5373                         /*
5374                          * REQ_GET_READ_MIRRORS does not contain this
5375                          * mirror, that means that the requested area
5376                          * is not left of the left cursor
5377                          */
5378                         ret = -EIO;
5379                         btrfs_put_bbio(tmp_bbio);
5380                         goto out;
5381                 }
5382
5383                 /*
5384                  * process the rest of the function using the mirror_num
5385                  * of the source drive. Therefore look it up first.
5386                  * At the end, patch the device pointer to the one of the
5387                  * target drive.
5388                  */
5389                 for (i = 0; i < tmp_num_stripes; i++) {
5390                         if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) {
5391                                 /*
5392                                  * In case of DUP, in order to keep it
5393                                  * simple, only add the mirror with the
5394                                  * lowest physical address
5395                                  */
5396                                 if (found &&
5397                                     physical_of_found <=
5398                                      tmp_bbio->stripes[i].physical)
5399                                         continue;
5400                                 index_srcdev = i;
5401                                 found = 1;
5402                                 physical_of_found =
5403                                         tmp_bbio->stripes[i].physical;
5404                         }
5405                 }
5406
5407                 if (found) {
5408                         mirror_num = index_srcdev + 1;
5409                         patch_the_first_stripe_for_dev_replace = 1;
5410                         physical_to_patch_in_first_stripe = physical_of_found;
5411                 } else {
5412                         WARN_ON(1);
5413                         ret = -EIO;
5414                         btrfs_put_bbio(tmp_bbio);
5415                         goto out;
5416                 }
5417
5418                 btrfs_put_bbio(tmp_bbio);
5419         } else if (mirror_num > map->num_stripes) {
5420                 mirror_num = 0;
5421         }
5422
5423         num_stripes = 1;
5424         stripe_index = 0;
5425         stripe_nr_orig = stripe_nr;
5426         stripe_nr_end = ALIGN(offset + *length, map->stripe_len);
5427         stripe_nr_end = div_u64(stripe_nr_end, map->stripe_len);
5428         stripe_end_offset = stripe_nr_end * map->stripe_len -
5429                             (offset + *length);
5430
5431         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5432                 if (rw & REQ_DISCARD)
5433                         num_stripes = min_t(u64, map->num_stripes,
5434                                             stripe_nr_end - stripe_nr_orig);
5435                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5436                                 &stripe_index);
5437                 if (!(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)))
5438                         mirror_num = 1;
5439         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
5440                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
5441                         num_stripes = map->num_stripes;
5442                 else if (mirror_num)
5443                         stripe_index = mirror_num - 1;
5444                 else {
5445                         stripe_index = find_live_mirror(fs_info, map, 0,
5446                                             map->num_stripes,
5447                                             current->pid % map->num_stripes,
5448                                             dev_replace_is_ongoing);
5449                         mirror_num = stripe_index + 1;
5450                 }
5451
5452         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
5453                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
5454                         num_stripes = map->num_stripes;
5455                 } else if (mirror_num) {
5456                         stripe_index = mirror_num - 1;
5457                 } else {
5458                         mirror_num = 1;
5459                 }
5460
5461         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5462                 u32 factor = map->num_stripes / map->sub_stripes;
5463
5464                 stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
5465                 stripe_index *= map->sub_stripes;
5466
5467                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
5468                         num_stripes = map->sub_stripes;
5469                 else if (rw & REQ_DISCARD)
5470                         num_stripes = min_t(u64, map->sub_stripes *
5471                                             (stripe_nr_end - stripe_nr_orig),
5472                                             map->num_stripes);
5473                 else if (mirror_num)
5474                         stripe_index += mirror_num - 1;
5475                 else {
5476                         int old_stripe_index = stripe_index;
5477                         stripe_index = find_live_mirror(fs_info, map,
5478                                               stripe_index,
5479                                               map->sub_stripes, stripe_index +
5480                                               current->pid % map->sub_stripes,
5481                                               dev_replace_is_ongoing);
5482                         mirror_num = stripe_index - old_stripe_index + 1;
5483                 }
5484
5485         } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5486                 if (need_raid_map &&
5487                     ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
5488                      mirror_num > 1)) {
5489                         /* push stripe_nr back to the start of the full stripe */
5490                         stripe_nr = div_u64(raid56_full_stripe_start,
5491                                         stripe_len * nr_data_stripes(map));
5492
5493                         /* RAID[56] write or recovery. Return all stripes */
5494                         num_stripes = map->num_stripes;
5495                         max_errors = nr_parity_stripes(map);
5496
5497                         *length = map->stripe_len;
5498                         stripe_index = 0;
5499                         stripe_offset = 0;
5500                 } else {
5501                         /*
5502                          * Mirror #0 or #1 means the original data block.
5503                          * Mirror #2 is RAID5 parity block.
5504                          * Mirror #3 is RAID6 Q block.
5505                          */
5506                         stripe_nr = div_u64_rem(stripe_nr,
5507                                         nr_data_stripes(map), &stripe_index);
5508                         if (mirror_num > 1)
5509                                 stripe_index = nr_data_stripes(map) +
5510                                                 mirror_num - 2;
5511
5512                         /* We distribute the parity blocks across stripes */
5513                         div_u64_rem(stripe_nr + stripe_index, map->num_stripes,
5514                                         &stripe_index);
5515                         if (!(rw & (REQ_WRITE | REQ_DISCARD |
5516                                     REQ_GET_READ_MIRRORS)) && mirror_num <= 1)
5517                                 mirror_num = 1;
5518                 }
5519         } else {
5520                 /*
5521                  * after this, stripe_nr is the number of stripes on this
5522                  * device we have to walk to find the data, and stripe_index is
5523                  * the number of our device in the stripe array
5524                  */
5525                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5526                                 &stripe_index);
5527                 mirror_num = stripe_index + 1;
5528         }
5529         BUG_ON(stripe_index >= map->num_stripes);
5530
5531         num_alloc_stripes = num_stripes;
5532         if (dev_replace_is_ongoing) {
5533                 if (rw & (REQ_WRITE | REQ_DISCARD))
5534                         num_alloc_stripes <<= 1;
5535                 if (rw & REQ_GET_READ_MIRRORS)
5536                         num_alloc_stripes++;
5537                 tgtdev_indexes = num_stripes;
5538         }
5539
5540         bbio = alloc_btrfs_bio(num_alloc_stripes, tgtdev_indexes);
5541         if (!bbio) {
5542                 ret = -ENOMEM;
5543                 goto out;
5544         }
5545         if (dev_replace_is_ongoing)
5546                 bbio->tgtdev_map = (int *)(bbio->stripes + num_alloc_stripes);
5547
5548         /* build raid_map */
5549         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK &&
5550             need_raid_map && ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
5551             mirror_num > 1)) {
5552                 u64 tmp;
5553                 unsigned rot;
5554
5555                 bbio->raid_map = (u64 *)((void *)bbio->stripes +
5556                                  sizeof(struct btrfs_bio_stripe) *
5557                                  num_alloc_stripes +
5558                                  sizeof(int) * tgtdev_indexes);
5559
5560                 /* Work out the disk rotation on this stripe-set */
5561                 div_u64_rem(stripe_nr, num_stripes, &rot);
5562
5563                 /* Fill in the logical address of each stripe */
5564                 tmp = stripe_nr * nr_data_stripes(map);
5565                 for (i = 0; i < nr_data_stripes(map); i++)
5566                         bbio->raid_map[(i+rot) % num_stripes] =
5567                                 em->start + (tmp + i) * map->stripe_len;
5568
5569                 bbio->raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
5570                 if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5571                         bbio->raid_map[(i+rot+1) % num_stripes] =
5572                                 RAID6_Q_STRIPE;
5573         }
5574
5575         if (rw & REQ_DISCARD) {
5576                 u32 factor = 0;
5577                 u32 sub_stripes = 0;
5578                 u64 stripes_per_dev = 0;
5579                 u32 remaining_stripes = 0;
5580                 u32 last_stripe = 0;
5581
5582                 if (map->type &
5583                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
5584                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5585                                 sub_stripes = 1;
5586                         else
5587                                 sub_stripes = map->sub_stripes;
5588
5589                         factor = map->num_stripes / sub_stripes;
5590                         stripes_per_dev = div_u64_rem(stripe_nr_end -
5591                                                       stripe_nr_orig,
5592                                                       factor,
5593                                                       &remaining_stripes);
5594                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
5595                         last_stripe *= sub_stripes;
5596                 }
5597
5598                 for (i = 0; i < num_stripes; i++) {
5599                         bbio->stripes[i].physical =
5600                                 map->stripes[stripe_index].physical +
5601                                 stripe_offset + stripe_nr * map->stripe_len;
5602                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
5603
5604                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
5605                                          BTRFS_BLOCK_GROUP_RAID10)) {
5606                                 bbio->stripes[i].length = stripes_per_dev *
5607                                                           map->stripe_len;
5608
5609                                 if (i / sub_stripes < remaining_stripes)
5610                                         bbio->stripes[i].length +=
5611                                                 map->stripe_len;
5612
5613                                 /*
5614                                  * Special for the first stripe and
5615                                  * the last stripe:
5616                                  *
5617                                  * |-------|...|-------|
5618                                  *     |----------|
5619                                  *    off     end_off
5620                                  */
5621                                 if (i < sub_stripes)
5622                                         bbio->stripes[i].length -=
5623                                                 stripe_offset;
5624
5625                                 if (stripe_index >= last_stripe &&
5626                                     stripe_index <= (last_stripe +
5627                                                      sub_stripes - 1))
5628                                         bbio->stripes[i].length -=
5629                                                 stripe_end_offset;
5630
5631                                 if (i == sub_stripes - 1)
5632                                         stripe_offset = 0;
5633                         } else
5634                                 bbio->stripes[i].length = *length;
5635
5636                         stripe_index++;
5637                         if (stripe_index == map->num_stripes) {
5638                                 /* This could only happen for RAID0/10 */
5639                                 stripe_index = 0;
5640                                 stripe_nr++;
5641                         }
5642                 }
5643         } else {
5644                 for (i = 0; i < num_stripes; i++) {
5645                         bbio->stripes[i].physical =
5646                                 map->stripes[stripe_index].physical +
5647                                 stripe_offset +
5648                                 stripe_nr * map->stripe_len;
5649                         bbio->stripes[i].dev =
5650                                 map->stripes[stripe_index].dev;
5651                         stripe_index++;
5652                 }
5653         }
5654
5655         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
5656                 max_errors = btrfs_chunk_max_errors(map);
5657
5658         if (bbio->raid_map)
5659                 sort_parity_stripes(bbio, num_stripes);
5660
5661         tgtdev_indexes = 0;
5662         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
5663             dev_replace->tgtdev != NULL) {
5664                 int index_where_to_add;
5665                 u64 srcdev_devid = dev_replace->srcdev->devid;
5666
5667                 /*
5668                  * duplicate the write operations while the dev replace
5669                  * procedure is running. Since the copying of the old disk
5670                  * to the new disk takes place at run time while the
5671                  * filesystem is mounted writable, the regular write
5672                  * operations to the old disk have to be duplicated to go
5673                  * to the new disk as well.
5674                  * Note that device->missing is handled by the caller, and
5675                  * that the write to the old disk is already set up in the
5676                  * stripes array.
5677                  */
5678                 index_where_to_add = num_stripes;
5679                 for (i = 0; i < num_stripes; i++) {
5680                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5681                                 /* write to new disk, too */
5682                                 struct btrfs_bio_stripe *new =
5683                                         bbio->stripes + index_where_to_add;
5684                                 struct btrfs_bio_stripe *old =
5685                                         bbio->stripes + i;
5686
5687                                 new->physical = old->physical;
5688                                 new->length = old->length;
5689                                 new->dev = dev_replace->tgtdev;
5690                                 bbio->tgtdev_map[i] = index_where_to_add;
5691                                 index_where_to_add++;
5692                                 max_errors++;
5693                                 tgtdev_indexes++;
5694                         }
5695                 }
5696                 num_stripes = index_where_to_add;
5697         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
5698                    dev_replace->tgtdev != NULL) {
5699                 u64 srcdev_devid = dev_replace->srcdev->devid;
5700                 int index_srcdev = 0;
5701                 int found = 0;
5702                 u64 physical_of_found = 0;
5703
5704                 /*
5705                  * During the dev-replace procedure, the target drive can
5706                  * also be used to read data in case it is needed to repair
5707                  * a corrupt block elsewhere. This is possible if the
5708                  * requested area is left of the left cursor. In this area,
5709                  * the target drive is a full copy of the source drive.
5710                  */
5711                 for (i = 0; i < num_stripes; i++) {
5712                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5713                                 /*
5714                                  * In case of DUP, in order to keep it
5715                                  * simple, only add the mirror with the
5716                                  * lowest physical address
5717                                  */
5718                                 if (found &&
5719                                     physical_of_found <=
5720                                      bbio->stripes[i].physical)
5721                                         continue;
5722                                 index_srcdev = i;
5723                                 found = 1;
5724                                 physical_of_found = bbio->stripes[i].physical;
5725                         }
5726                 }
5727                 if (found) {
5728                         if (physical_of_found + map->stripe_len <=
5729                             dev_replace->cursor_left) {
5730                                 struct btrfs_bio_stripe *tgtdev_stripe =
5731                                         bbio->stripes + num_stripes;
5732
5733                                 tgtdev_stripe->physical = physical_of_found;
5734                                 tgtdev_stripe->length =
5735                                         bbio->stripes[index_srcdev].length;
5736                                 tgtdev_stripe->dev = dev_replace->tgtdev;
5737                                 bbio->tgtdev_map[index_srcdev] = num_stripes;
5738
5739                                 tgtdev_indexes++;
5740                                 num_stripes++;
5741                         }
5742                 }
5743         }
5744
5745         *bbio_ret = bbio;
5746         bbio->map_type = map->type;
5747         bbio->num_stripes = num_stripes;
5748         bbio->max_errors = max_errors;
5749         bbio->mirror_num = mirror_num;
5750         bbio->num_tgtdevs = tgtdev_indexes;
5751
5752         /*
5753          * this is the case that REQ_READ && dev_replace_is_ongoing &&
5754          * mirror_num == num_stripes + 1 && dev_replace target drive is
5755          * available as a mirror
5756          */
5757         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
5758                 WARN_ON(num_stripes > 1);
5759                 bbio->stripes[0].dev = dev_replace->tgtdev;
5760                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
5761                 bbio->mirror_num = map->num_stripes + 1;
5762         }
5763 out:
5764         if (dev_replace_is_ongoing)
5765                 btrfs_dev_replace_unlock(dev_replace);
5766         free_extent_map(em);
5767         return ret;
5768 }
5769
5770 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5771                       u64 logical, u64 *length,
5772                       struct btrfs_bio **bbio_ret, int mirror_num)
5773 {
5774         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5775                                  mirror_num, 0);
5776 }
5777
5778 /* For Scrub/replace */
5779 int btrfs_map_sblock(struct btrfs_fs_info *fs_info, int rw,
5780                      u64 logical, u64 *length,
5781                      struct btrfs_bio **bbio_ret, int mirror_num,
5782                      int need_raid_map)
5783 {
5784         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5785                                  mirror_num, need_raid_map);
5786 }
5787
5788 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
5789                      u64 chunk_start, u64 physical, u64 devid,
5790                      u64 **logical, int *naddrs, int *stripe_len)
5791 {
5792         struct extent_map_tree *em_tree = &map_tree->map_tree;
5793         struct extent_map *em;
5794         struct map_lookup *map;
5795         u64 *buf;
5796         u64 bytenr;
5797         u64 length;
5798         u64 stripe_nr;
5799         u64 rmap_len;
5800         int i, j, nr = 0;
5801
5802         read_lock(&em_tree->lock);
5803         em = lookup_extent_mapping(em_tree, chunk_start, 1);
5804         read_unlock(&em_tree->lock);
5805
5806         if (!em) {
5807                 printk(KERN_ERR "BTRFS: couldn't find em for chunk %Lu\n",
5808                        chunk_start);
5809                 return -EIO;
5810         }
5811
5812         if (em->start != chunk_start) {
5813                 printk(KERN_ERR "BTRFS: bad chunk start, em=%Lu, wanted=%Lu\n",
5814                        em->start, chunk_start);
5815                 free_extent_map(em);
5816                 return -EIO;
5817         }
5818         map = em->map_lookup;
5819
5820         length = em->len;
5821         rmap_len = map->stripe_len;
5822
5823         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5824                 length = div_u64(length, map->num_stripes / map->sub_stripes);
5825         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5826                 length = div_u64(length, map->num_stripes);
5827         else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5828                 length = div_u64(length, nr_data_stripes(map));
5829                 rmap_len = map->stripe_len * nr_data_stripes(map);
5830         }
5831
5832         buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
5833         BUG_ON(!buf); /* -ENOMEM */
5834
5835         for (i = 0; i < map->num_stripes; i++) {
5836                 if (devid && map->stripes[i].dev->devid != devid)
5837                         continue;
5838                 if (map->stripes[i].physical > physical ||
5839                     map->stripes[i].physical + length <= physical)
5840                         continue;
5841
5842                 stripe_nr = physical - map->stripes[i].physical;
5843                 stripe_nr = div_u64(stripe_nr, map->stripe_len);
5844
5845                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5846                         stripe_nr = stripe_nr * map->num_stripes + i;
5847                         stripe_nr = div_u64(stripe_nr, map->sub_stripes);
5848                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5849                         stripe_nr = stripe_nr * map->num_stripes + i;
5850                 } /* else if RAID[56], multiply by nr_data_stripes().
5851                    * Alternatively, just use rmap_len below instead of
5852                    * map->stripe_len */
5853
5854                 bytenr = chunk_start + stripe_nr * rmap_len;
5855                 WARN_ON(nr >= map->num_stripes);
5856                 for (j = 0; j < nr; j++) {
5857                         if (buf[j] == bytenr)
5858                                 break;
5859                 }
5860                 if (j == nr) {
5861                         WARN_ON(nr >= map->num_stripes);
5862                         buf[nr++] = bytenr;
5863                 }
5864         }
5865
5866         *logical = buf;
5867         *naddrs = nr;
5868         *stripe_len = rmap_len;
5869
5870         free_extent_map(em);
5871         return 0;
5872 }
5873
5874 static inline void btrfs_end_bbio(struct btrfs_bio *bbio, struct bio *bio)
5875 {
5876         bio->bi_private = bbio->private;
5877         bio->bi_end_io = bbio->end_io;
5878         bio_endio(bio);
5879
5880         btrfs_put_bbio(bbio);
5881 }
5882
5883 static void btrfs_end_bio(struct bio *bio)
5884 {
5885         struct btrfs_bio *bbio = bio->bi_private;
5886         int is_orig_bio = 0;
5887
5888         if (bio->bi_error) {
5889                 atomic_inc(&bbio->error);
5890                 if (bio->bi_error == -EIO || bio->bi_error == -EREMOTEIO) {
5891                         unsigned int stripe_index =
5892                                 btrfs_io_bio(bio)->stripe_index;
5893                         struct btrfs_device *dev;
5894
5895                         BUG_ON(stripe_index >= bbio->num_stripes);
5896                         dev = bbio->stripes[stripe_index].dev;
5897                         if (dev->bdev) {
5898                                 if (bio->bi_rw & WRITE)
5899                                         btrfs_dev_stat_inc(dev,
5900                                                 BTRFS_DEV_STAT_WRITE_ERRS);
5901                                 else
5902                                         btrfs_dev_stat_inc(dev,
5903                                                 BTRFS_DEV_STAT_READ_ERRS);
5904                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
5905                                         btrfs_dev_stat_inc(dev,
5906                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
5907                                 btrfs_dev_stat_print_on_error(dev);
5908                         }
5909                 }
5910         }
5911
5912         if (bio == bbio->orig_bio)
5913                 is_orig_bio = 1;
5914
5915         btrfs_bio_counter_dec(bbio->fs_info);
5916
5917         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5918                 if (!is_orig_bio) {
5919                         bio_put(bio);
5920                         bio = bbio->orig_bio;
5921                 }
5922
5923                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
5924                 /* only send an error to the higher layers if it is
5925                  * beyond the tolerance of the btrfs bio
5926                  */
5927                 if (atomic_read(&bbio->error) > bbio->max_errors) {
5928                         bio->bi_error = -EIO;
5929                 } else {
5930                         /*
5931                          * this bio is actually up to date, we didn't
5932                          * go over the max number of errors
5933                          */
5934                         bio->bi_error = 0;
5935                 }
5936
5937                 btrfs_end_bbio(bbio, bio);
5938         } else if (!is_orig_bio) {
5939                 bio_put(bio);
5940         }
5941 }
5942
5943 /*
5944  * see run_scheduled_bios for a description of why bios are collected for
5945  * async submit.
5946  *
5947  * This will add one bio to the pending list for a device and make sure
5948  * the work struct is scheduled.
5949  */
5950 static noinline void btrfs_schedule_bio(struct btrfs_root *root,
5951                                         struct btrfs_device *device,
5952                                         int rw, struct bio *bio)
5953 {
5954         int should_queue = 1;
5955         struct btrfs_pending_bios *pending_bios;
5956
5957         if (device->missing || !device->bdev) {
5958                 bio_io_error(bio);
5959                 return;
5960         }
5961
5962         /* don't bother with additional async steps for reads, right now */
5963         if (!(rw & REQ_WRITE)) {
5964                 bio_get(bio);
5965                 btrfsic_submit_bio(rw, bio);
5966                 bio_put(bio);
5967                 return;
5968         }
5969
5970         /*
5971          * nr_async_bios allows us to reliably return congestion to the
5972          * higher layers.  Otherwise, the async bio makes it appear we have
5973          * made progress against dirty pages when we've really just put it
5974          * on a queue for later
5975          */
5976         atomic_inc(&root->fs_info->nr_async_bios);
5977         WARN_ON(bio->bi_next);
5978         bio->bi_next = NULL;
5979         bio->bi_rw |= rw;
5980
5981         spin_lock(&device->io_lock);
5982         if (bio->bi_rw & REQ_SYNC)
5983                 pending_bios = &device->pending_sync_bios;
5984         else
5985                 pending_bios = &device->pending_bios;
5986
5987         if (pending_bios->tail)
5988                 pending_bios->tail->bi_next = bio;
5989
5990         pending_bios->tail = bio;
5991         if (!pending_bios->head)
5992                 pending_bios->head = bio;
5993         if (device->running_pending)
5994                 should_queue = 0;
5995
5996         spin_unlock(&device->io_lock);
5997
5998         if (should_queue)
5999                 btrfs_queue_work(root->fs_info->submit_workers,
6000                                  &device->work);
6001 }
6002
6003 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
6004                               struct bio *bio, u64 physical, int dev_nr,
6005                               int rw, int async)
6006 {
6007         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
6008
6009         bio->bi_private = bbio;
6010         btrfs_io_bio(bio)->stripe_index = dev_nr;
6011         bio->bi_end_io = btrfs_end_bio;
6012         bio->bi_iter.bi_sector = physical >> 9;
6013 #ifdef DEBUG
6014         {
6015                 struct rcu_string *name;
6016
6017                 rcu_read_lock();
6018                 name = rcu_dereference(dev->name);
6019                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
6020                          "(%s id %llu), size=%u\n", rw,
6021                          (u64)bio->bi_iter.bi_sector, (u_long)dev->bdev->bd_dev,
6022                          name->str, dev->devid, bio->bi_iter.bi_size);
6023                 rcu_read_unlock();
6024         }
6025 #endif
6026         bio->bi_bdev = dev->bdev;
6027
6028         btrfs_bio_counter_inc_noblocked(root->fs_info);
6029
6030         if (async)
6031                 btrfs_schedule_bio(root, dev, rw, bio);
6032         else
6033                 btrfsic_submit_bio(rw, bio);
6034 }
6035
6036 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
6037 {
6038         atomic_inc(&bbio->error);
6039         if (atomic_dec_and_test(&bbio->stripes_pending)) {
6040                 /* Shoud be the original bio. */
6041                 WARN_ON(bio != bbio->orig_bio);
6042
6043                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
6044                 bio->bi_iter.bi_sector = logical >> 9;
6045                 bio->bi_error = -EIO;
6046                 btrfs_end_bbio(bbio, bio);
6047         }
6048 }
6049
6050 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
6051                   int mirror_num, int async_submit)
6052 {
6053         struct btrfs_device *dev;
6054         struct bio *first_bio = bio;
6055         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
6056         u64 length = 0;
6057         u64 map_length;
6058         int ret;
6059         int dev_nr;
6060         int total_devs;
6061         struct btrfs_bio *bbio = NULL;
6062
6063         length = bio->bi_iter.bi_size;
6064         map_length = length;
6065
6066         btrfs_bio_counter_inc_blocked(root->fs_info);
6067         ret = __btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
6068                               mirror_num, 1);
6069         if (ret) {
6070                 btrfs_bio_counter_dec(root->fs_info);
6071                 return ret;
6072         }
6073
6074         total_devs = bbio->num_stripes;
6075         bbio->orig_bio = first_bio;
6076         bbio->private = first_bio->bi_private;
6077         bbio->end_io = first_bio->bi_end_io;
6078         bbio->fs_info = root->fs_info;
6079         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
6080
6081         if (bbio->raid_map) {
6082                 /* In this case, map_length has been set to the length of
6083                    a single stripe; not the whole write */
6084                 if (rw & WRITE) {
6085                         ret = raid56_parity_write(root, bio, bbio, map_length);
6086                 } else {
6087                         ret = raid56_parity_recover(root, bio, bbio, map_length,
6088                                                     mirror_num, 1);
6089                 }
6090
6091                 btrfs_bio_counter_dec(root->fs_info);
6092                 return ret;
6093         }
6094
6095         if (map_length < length) {
6096                 btrfs_crit(root->fs_info, "mapping failed logical %llu bio len %llu len %llu",
6097                         logical, length, map_length);
6098                 BUG();
6099         }
6100
6101         for (dev_nr = 0; dev_nr < total_devs; dev_nr++) {
6102                 dev = bbio->stripes[dev_nr].dev;
6103                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
6104                         bbio_error(bbio, first_bio, logical);
6105                         continue;
6106                 }
6107
6108                 if (dev_nr < total_devs - 1) {
6109                         bio = btrfs_bio_clone(first_bio, GFP_NOFS);
6110                         BUG_ON(!bio); /* -ENOMEM */
6111                 } else
6112                         bio = first_bio;
6113
6114                 submit_stripe_bio(root, bbio, bio,
6115                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
6116                                   async_submit);
6117         }
6118         btrfs_bio_counter_dec(root->fs_info);
6119         return 0;
6120 }
6121
6122 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
6123                                        u8 *uuid, u8 *fsid)
6124 {
6125         struct btrfs_device *device;
6126         struct btrfs_fs_devices *cur_devices;
6127
6128         cur_devices = fs_info->fs_devices;
6129         while (cur_devices) {
6130                 if (!fsid ||
6131                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
6132                         device = __find_device(&cur_devices->devices,
6133                                                devid, uuid);
6134                         if (device)
6135                                 return device;
6136                 }
6137                 cur_devices = cur_devices->seed;
6138         }
6139         return NULL;
6140 }
6141
6142 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
6143                                             struct btrfs_fs_devices *fs_devices,
6144                                             u64 devid, u8 *dev_uuid)
6145 {
6146         struct btrfs_device *device;
6147
6148         device = btrfs_alloc_device(NULL, &devid, dev_uuid);
6149         if (IS_ERR(device))
6150                 return NULL;
6151
6152         list_add(&device->dev_list, &fs_devices->devices);
6153         device->fs_devices = fs_devices;
6154         fs_devices->num_devices++;
6155
6156         device->missing = 1;
6157         fs_devices->missing_devices++;
6158
6159         return device;
6160 }
6161
6162 /**
6163  * btrfs_alloc_device - allocate struct btrfs_device
6164  * @fs_info:    used only for generating a new devid, can be NULL if
6165  *              devid is provided (i.e. @devid != NULL).
6166  * @devid:      a pointer to devid for this device.  If NULL a new devid
6167  *              is generated.
6168  * @uuid:       a pointer to UUID for this device.  If NULL a new UUID
6169  *              is generated.
6170  *
6171  * Return: a pointer to a new &struct btrfs_device on success; ERR_PTR()
6172  * on error.  Returned struct is not linked onto any lists and can be
6173  * destroyed with kfree() right away.
6174  */
6175 struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
6176                                         const u64 *devid,
6177                                         const u8 *uuid)
6178 {
6179         struct btrfs_device *dev;
6180         u64 tmp;
6181
6182         if (WARN_ON(!devid && !fs_info))
6183                 return ERR_PTR(-EINVAL);
6184
6185         dev = __alloc_device();
6186         if (IS_ERR(dev))
6187                 return dev;
6188
6189         if (devid)
6190                 tmp = *devid;
6191         else {
6192                 int ret;
6193
6194                 ret = find_next_devid(fs_info, &tmp);
6195                 if (ret) {
6196                         kfree(dev);
6197                         return ERR_PTR(ret);
6198                 }
6199         }
6200         dev->devid = tmp;
6201
6202         if (uuid)
6203                 memcpy(dev->uuid, uuid, BTRFS_UUID_SIZE);
6204         else
6205                 generate_random_uuid(dev->uuid);
6206
6207         btrfs_init_work(&dev->work, btrfs_submit_helper,
6208                         pending_bios_fn, NULL, NULL);
6209
6210         return dev;
6211 }
6212
6213 /* Return -EIO if any error, otherwise return 0. */
6214 static int btrfs_check_chunk_valid(struct btrfs_root *root,
6215                                    struct extent_buffer *leaf,
6216                                    struct btrfs_chunk *chunk, u64 logical)
6217 {
6218         u64 length;
6219         u64 stripe_len;
6220         u16 num_stripes;
6221         u16 sub_stripes;
6222         u64 type;
6223         u64 features;
6224         bool mixed = false;
6225
6226         length = btrfs_chunk_length(leaf, chunk);
6227         stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
6228         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
6229         sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
6230         type = btrfs_chunk_type(leaf, chunk);
6231
6232         if (!num_stripes) {
6233                 btrfs_err(root->fs_info, "invalid chunk num_stripes: %u",
6234                           num_stripes);
6235                 return -EIO;
6236         }
6237         if (!IS_ALIGNED(logical, root->sectorsize)) {
6238                 btrfs_err(root->fs_info,
6239                           "invalid chunk logical %llu", logical);
6240                 return -EIO;
6241         }
6242         if (btrfs_chunk_sector_size(leaf, chunk) != root->sectorsize) {
6243                 btrfs_err(root->fs_info, "invalid chunk sectorsize %u",
6244                           btrfs_chunk_sector_size(leaf, chunk));
6245                 return -EIO;
6246         }
6247         if (!length || !IS_ALIGNED(length, root->sectorsize)) {
6248                 btrfs_err(root->fs_info,
6249                         "invalid chunk length %llu", length);
6250                 return -EIO;
6251         }
6252         if (!is_power_of_2(stripe_len)) {
6253                 btrfs_err(root->fs_info, "invalid chunk stripe length: %llu",
6254                           stripe_len);
6255                 return -EIO;
6256         }
6257         if (~(BTRFS_BLOCK_GROUP_TYPE_MASK | BTRFS_BLOCK_GROUP_PROFILE_MASK) &
6258             type) {
6259                 btrfs_err(root->fs_info, "unrecognized chunk type: %llu",
6260                           ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
6261                             BTRFS_BLOCK_GROUP_PROFILE_MASK) &
6262                           btrfs_chunk_type(leaf, chunk));
6263                 return -EIO;
6264         }
6265
6266         if (!is_power_of_2(type & BTRFS_BLOCK_GROUP_PROFILE_MASK) &&
6267             (type & BTRFS_BLOCK_GROUP_PROFILE_MASK) != 0) {
6268                 btrfs_err(root->fs_info,
6269                 "invalid chunk profile flag: 0x%llx, expect 0 or 1 bit set",
6270                           type & BTRFS_BLOCK_GROUP_PROFILE_MASK);
6271                 return -EUCLEAN;
6272         }
6273         if ((type & BTRFS_BLOCK_GROUP_TYPE_MASK) == 0) {
6274                 btrfs_err(root->fs_info, "missing chunk type flag: 0x%llx", type);
6275                 return -EIO;
6276         }
6277
6278         if ((type & BTRFS_BLOCK_GROUP_SYSTEM) &&
6279             (type & (BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA))) {
6280                 btrfs_err(root->fs_info,
6281                         "system chunk with data or metadata type: 0x%llx", type);
6282                 return -EIO;
6283         }
6284
6285         features = btrfs_super_incompat_flags(root->fs_info->super_copy);
6286         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
6287                 mixed = true;
6288
6289         if (!mixed) {
6290                 if ((type & BTRFS_BLOCK_GROUP_METADATA) &&
6291                     (type & BTRFS_BLOCK_GROUP_DATA)) {
6292                         btrfs_err(root->fs_info,
6293                         "mixed chunk type in non-mixed mode: 0x%llx", type);
6294                         return -EIO;
6295                 }
6296         }
6297
6298         if ((type & BTRFS_BLOCK_GROUP_RAID10 && sub_stripes != 2) ||
6299             (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes != 2) ||
6300             (type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) ||
6301             (type & BTRFS_BLOCK_GROUP_RAID6 && num_stripes < 3) ||
6302             (type & BTRFS_BLOCK_GROUP_DUP && num_stripes != 2) ||
6303             ((type & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 &&
6304              num_stripes != 1)) {
6305                 btrfs_err(root->fs_info,
6306                         "invalid num_stripes:sub_stripes %u:%u for profile %llu",
6307                         num_stripes, sub_stripes,
6308                         type & BTRFS_BLOCK_GROUP_PROFILE_MASK);
6309                 return -EIO;
6310         }
6311
6312         return 0;
6313 }
6314
6315 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
6316                           struct extent_buffer *leaf,
6317                           struct btrfs_chunk *chunk)
6318 {
6319         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
6320         struct map_lookup *map;
6321         struct extent_map *em;
6322         u64 logical;
6323         u64 length;
6324         u64 stripe_len;
6325         u64 devid;
6326         u8 uuid[BTRFS_UUID_SIZE];
6327         int num_stripes;
6328         int ret;
6329         int i;
6330
6331         logical = key->offset;
6332         length = btrfs_chunk_length(leaf, chunk);
6333         stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
6334         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
6335
6336         ret = btrfs_check_chunk_valid(root, leaf, chunk, logical);
6337         if (ret)
6338                 return ret;
6339
6340         read_lock(&map_tree->map_tree.lock);
6341         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
6342         read_unlock(&map_tree->map_tree.lock);
6343
6344         /* already mapped? */
6345         if (em && em->start <= logical && em->start + em->len > logical) {
6346                 free_extent_map(em);
6347                 return 0;
6348         } else if (em) {
6349                 free_extent_map(em);
6350         }
6351
6352         em = alloc_extent_map();
6353         if (!em)
6354                 return -ENOMEM;
6355         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
6356         if (!map) {
6357                 free_extent_map(em);
6358                 return -ENOMEM;
6359         }
6360
6361         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
6362         em->map_lookup = map;
6363         em->start = logical;
6364         em->len = length;
6365         em->orig_start = 0;
6366         em->block_start = 0;
6367         em->block_len = em->len;
6368
6369         map->num_stripes = num_stripes;
6370         map->io_width = btrfs_chunk_io_width(leaf, chunk);
6371         map->io_align = btrfs_chunk_io_align(leaf, chunk);
6372         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
6373         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
6374         map->type = btrfs_chunk_type(leaf, chunk);
6375         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
6376         for (i = 0; i < num_stripes; i++) {
6377                 map->stripes[i].physical =
6378                         btrfs_stripe_offset_nr(leaf, chunk, i);
6379                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
6380                 read_extent_buffer(leaf, uuid, (unsigned long)
6381                                    btrfs_stripe_dev_uuid_nr(chunk, i),
6382                                    BTRFS_UUID_SIZE);
6383                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
6384                                                         uuid, NULL);
6385                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
6386                         free_extent_map(em);
6387                         return -EIO;
6388                 }
6389                 if (!map->stripes[i].dev) {
6390                         map->stripes[i].dev =
6391                                 add_missing_dev(root, root->fs_info->fs_devices,
6392                                                 devid, uuid);
6393                         if (!map->stripes[i].dev) {
6394                                 free_extent_map(em);
6395                                 return -EIO;
6396                         }
6397                         btrfs_warn(root->fs_info, "devid %llu uuid %pU is missing",
6398                                                 devid, uuid);
6399                 }
6400                 map->stripes[i].dev->in_fs_metadata = 1;
6401         }
6402
6403         write_lock(&map_tree->map_tree.lock);
6404         ret = add_extent_mapping(&map_tree->map_tree, em, 0);
6405         write_unlock(&map_tree->map_tree.lock);
6406         BUG_ON(ret); /* Tree corruption */
6407         free_extent_map(em);
6408
6409         return 0;
6410 }
6411
6412 static void fill_device_from_item(struct extent_buffer *leaf,
6413                                  struct btrfs_dev_item *dev_item,
6414                                  struct btrfs_device *device)
6415 {
6416         unsigned long ptr;
6417
6418         device->devid = btrfs_device_id(leaf, dev_item);
6419         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
6420         device->total_bytes = device->disk_total_bytes;
6421         device->commit_total_bytes = device->disk_total_bytes;
6422         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
6423         device->commit_bytes_used = device->bytes_used;
6424         device->type = btrfs_device_type(leaf, dev_item);
6425         device->io_align = btrfs_device_io_align(leaf, dev_item);
6426         device->io_width = btrfs_device_io_width(leaf, dev_item);
6427         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
6428         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
6429         device->is_tgtdev_for_dev_replace = 0;
6430
6431         ptr = btrfs_device_uuid(dev_item);
6432         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
6433 }
6434
6435 static struct btrfs_fs_devices *open_seed_devices(struct btrfs_root *root,
6436                                                   u8 *fsid)
6437 {
6438         struct btrfs_fs_devices *fs_devices;
6439         int ret;
6440
6441         BUG_ON(!mutex_is_locked(&uuid_mutex));
6442
6443         fs_devices = root->fs_info->fs_devices->seed;
6444         while (fs_devices) {
6445                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE))
6446                         return fs_devices;
6447
6448                 fs_devices = fs_devices->seed;
6449         }
6450
6451         fs_devices = find_fsid(fsid);
6452         if (!fs_devices) {
6453                 if (!btrfs_test_opt(root, DEGRADED))
6454                         return ERR_PTR(-ENOENT);
6455
6456                 fs_devices = alloc_fs_devices(fsid);
6457                 if (IS_ERR(fs_devices))
6458                         return fs_devices;
6459
6460                 fs_devices->seeding = 1;
6461                 fs_devices->opened = 1;
6462                 return fs_devices;
6463         }
6464
6465         fs_devices = clone_fs_devices(fs_devices);
6466         if (IS_ERR(fs_devices))
6467                 return fs_devices;
6468
6469         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
6470                                    root->fs_info->bdev_holder);
6471         if (ret) {
6472                 free_fs_devices(fs_devices);
6473                 fs_devices = ERR_PTR(ret);
6474                 goto out;
6475         }
6476
6477         if (!fs_devices->seeding) {
6478                 __btrfs_close_devices(fs_devices);
6479                 free_fs_devices(fs_devices);
6480                 fs_devices = ERR_PTR(-EINVAL);
6481                 goto out;
6482         }
6483
6484         fs_devices->seed = root->fs_info->fs_devices->seed;
6485         root->fs_info->fs_devices->seed = fs_devices;
6486 out:
6487         return fs_devices;
6488 }
6489
6490 static int read_one_dev(struct btrfs_root *root,
6491                         struct extent_buffer *leaf,
6492                         struct btrfs_dev_item *dev_item)
6493 {
6494         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6495         struct btrfs_device *device;
6496         u64 devid;
6497         int ret;
6498         u8 fs_uuid[BTRFS_UUID_SIZE];
6499         u8 dev_uuid[BTRFS_UUID_SIZE];
6500
6501         devid = btrfs_device_id(leaf, dev_item);
6502         read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
6503                            BTRFS_UUID_SIZE);
6504         read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
6505                            BTRFS_UUID_SIZE);
6506
6507         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
6508                 fs_devices = open_seed_devices(root, fs_uuid);
6509                 if (IS_ERR(fs_devices))
6510                         return PTR_ERR(fs_devices);
6511         }
6512
6513         device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
6514         if (!device) {
6515                 if (!btrfs_test_opt(root, DEGRADED))
6516                         return -EIO;
6517
6518                 device = add_missing_dev(root, fs_devices, devid, dev_uuid);
6519                 if (!device)
6520                         return -ENOMEM;
6521                 btrfs_warn(root->fs_info, "devid %llu uuid %pU missing",
6522                                 devid, dev_uuid);
6523         } else {
6524                 if (!device->bdev && !btrfs_test_opt(root, DEGRADED))
6525                         return -EIO;
6526
6527                 if(!device->bdev && !device->missing) {
6528                         /*
6529                          * this happens when a device that was properly setup
6530                          * in the device info lists suddenly goes bad.
6531                          * device->bdev is NULL, and so we have to set
6532                          * device->missing to one here
6533                          */
6534                         device->fs_devices->missing_devices++;
6535                         device->missing = 1;
6536                 }
6537
6538                 /* Move the device to its own fs_devices */
6539                 if (device->fs_devices != fs_devices) {
6540                         ASSERT(device->missing);
6541
6542                         list_move(&device->dev_list, &fs_devices->devices);
6543                         device->fs_devices->num_devices--;
6544                         fs_devices->num_devices++;
6545
6546                         device->fs_devices->missing_devices--;
6547                         fs_devices->missing_devices++;
6548
6549                         device->fs_devices = fs_devices;
6550                 }
6551         }
6552
6553         if (device->fs_devices != root->fs_info->fs_devices) {
6554                 BUG_ON(device->writeable);
6555                 if (device->generation !=
6556                     btrfs_device_generation(leaf, dev_item))
6557                         return -EINVAL;
6558         }
6559
6560         fill_device_from_item(leaf, dev_item, device);
6561         device->in_fs_metadata = 1;
6562         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
6563                 device->fs_devices->total_rw_bytes += device->total_bytes;
6564                 spin_lock(&root->fs_info->free_chunk_lock);
6565                 root->fs_info->free_chunk_space += device->total_bytes -
6566                         device->bytes_used;
6567                 spin_unlock(&root->fs_info->free_chunk_lock);
6568         }
6569         ret = 0;
6570         return ret;
6571 }
6572
6573 int btrfs_read_sys_array(struct btrfs_root *root)
6574 {
6575         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
6576         struct extent_buffer *sb;
6577         struct btrfs_disk_key *disk_key;
6578         struct btrfs_chunk *chunk;
6579         u8 *array_ptr;
6580         unsigned long sb_array_offset;
6581         int ret = 0;
6582         u32 num_stripes;
6583         u32 array_size;
6584         u32 len = 0;
6585         u32 cur_offset;
6586         u64 type;
6587         struct btrfs_key key;
6588
6589         ASSERT(BTRFS_SUPER_INFO_SIZE <= root->nodesize);
6590         /*
6591          * This will create extent buffer of nodesize, superblock size is
6592          * fixed to BTRFS_SUPER_INFO_SIZE. If nodesize > sb size, this will
6593          * overallocate but we can keep it as-is, only the first page is used.
6594          */
6595         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET);
6596         if (!sb)
6597                 return -ENOMEM;
6598         btrfs_set_buffer_uptodate(sb);
6599         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
6600         /*
6601          * The sb extent buffer is artifical and just used to read the system array.
6602          * btrfs_set_buffer_uptodate() call does not properly mark all it's
6603          * pages up-to-date when the page is larger: extent does not cover the
6604          * whole page and consequently check_page_uptodate does not find all
6605          * the page's extents up-to-date (the hole beyond sb),
6606          * write_extent_buffer then triggers a WARN_ON.
6607          *
6608          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
6609          * but sb spans only this function. Add an explicit SetPageUptodate call
6610          * to silence the warning eg. on PowerPC 64.
6611          */
6612         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
6613                 SetPageUptodate(sb->pages[0]);
6614
6615         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
6616         array_size = btrfs_super_sys_array_size(super_copy);
6617
6618         array_ptr = super_copy->sys_chunk_array;
6619         sb_array_offset = offsetof(struct btrfs_super_block, sys_chunk_array);
6620         cur_offset = 0;
6621
6622         while (cur_offset < array_size) {
6623                 disk_key = (struct btrfs_disk_key *)array_ptr;
6624                 len = sizeof(*disk_key);
6625                 if (cur_offset + len > array_size)
6626                         goto out_short_read;
6627
6628                 btrfs_disk_key_to_cpu(&key, disk_key);
6629
6630                 array_ptr += len;
6631                 sb_array_offset += len;
6632                 cur_offset += len;
6633
6634                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
6635                         chunk = (struct btrfs_chunk *)sb_array_offset;
6636                         /*
6637                          * At least one btrfs_chunk with one stripe must be
6638                          * present, exact stripe count check comes afterwards
6639                          */
6640                         len = btrfs_chunk_item_size(1);
6641                         if (cur_offset + len > array_size)
6642                                 goto out_short_read;
6643
6644                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
6645                         if (!num_stripes) {
6646                                 printk(KERN_ERR
6647             "BTRFS: invalid number of stripes %u in sys_array at offset %u\n",
6648                                         num_stripes, cur_offset);
6649                                 ret = -EIO;
6650                                 break;
6651                         }
6652
6653                         type = btrfs_chunk_type(sb, chunk);
6654                         if ((type & BTRFS_BLOCK_GROUP_SYSTEM) == 0) {
6655                                 btrfs_err(root->fs_info,
6656                             "invalid chunk type %llu in sys_array at offset %u",
6657                                         type, cur_offset);
6658                                 ret = -EIO;
6659                                 break;
6660                         }
6661
6662                         len = btrfs_chunk_item_size(num_stripes);
6663                         if (cur_offset + len > array_size)
6664                                 goto out_short_read;
6665
6666                         ret = read_one_chunk(root, &key, sb, chunk);
6667                         if (ret)
6668                                 break;
6669                 } else {
6670                         ret = -EIO;
6671                         break;
6672                 }
6673                 array_ptr += len;
6674                 sb_array_offset += len;
6675                 cur_offset += len;
6676         }
6677         free_extent_buffer(sb);
6678         return ret;
6679
6680 out_short_read:
6681         printk(KERN_ERR "BTRFS: sys_array too short to read %u bytes at offset %u\n",
6682                         len, cur_offset);
6683         free_extent_buffer(sb);
6684         return -EIO;
6685 }
6686
6687 int btrfs_read_chunk_tree(struct btrfs_root *root)
6688 {
6689         struct btrfs_path *path;
6690         struct extent_buffer *leaf;
6691         struct btrfs_key key;
6692         struct btrfs_key found_key;
6693         int ret;
6694         int slot;
6695
6696         root = root->fs_info->chunk_root;
6697
6698         path = btrfs_alloc_path();
6699         if (!path)
6700                 return -ENOMEM;
6701
6702         mutex_lock(&uuid_mutex);
6703         lock_chunks(root);
6704
6705         /*
6706          * It is possible for mount and umount to race in such a way that
6707          * we execute this code path, but open_fs_devices failed to clear
6708          * total_rw_bytes. We certainly want it cleared before reading the
6709          * device items, so clear it here.
6710          */
6711         root->fs_info->fs_devices->total_rw_bytes = 0;
6712
6713         /*
6714          * Read all device items, and then all the chunk items. All
6715          * device items are found before any chunk item (their object id
6716          * is smaller than the lowest possible object id for a chunk
6717          * item - BTRFS_FIRST_CHUNK_TREE_OBJECTID).
6718          */
6719         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
6720         key.offset = 0;
6721         key.type = 0;
6722         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6723         if (ret < 0)
6724                 goto error;
6725         while (1) {
6726                 leaf = path->nodes[0];
6727                 slot = path->slots[0];
6728                 if (slot >= btrfs_header_nritems(leaf)) {
6729                         ret = btrfs_next_leaf(root, path);
6730                         if (ret == 0)
6731                                 continue;
6732                         if (ret < 0)
6733                                 goto error;
6734                         break;
6735                 }
6736                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6737                 if (found_key.type == BTRFS_DEV_ITEM_KEY) {
6738                         struct btrfs_dev_item *dev_item;
6739                         dev_item = btrfs_item_ptr(leaf, slot,
6740                                                   struct btrfs_dev_item);
6741                         ret = read_one_dev(root, leaf, dev_item);
6742                         if (ret)
6743                                 goto error;
6744                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
6745                         struct btrfs_chunk *chunk;
6746                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
6747                         ret = read_one_chunk(root, &found_key, leaf, chunk);
6748                         if (ret)
6749                                 goto error;
6750                 }
6751                 path->slots[0]++;
6752         }
6753         ret = 0;
6754 error:
6755         unlock_chunks(root);
6756         mutex_unlock(&uuid_mutex);
6757
6758         btrfs_free_path(path);
6759         return ret;
6760 }
6761
6762 void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
6763 {
6764         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6765         struct btrfs_device *device;
6766
6767         while (fs_devices) {
6768                 mutex_lock(&fs_devices->device_list_mutex);
6769                 list_for_each_entry(device, &fs_devices->devices, dev_list)
6770                         device->dev_root = fs_info->dev_root;
6771                 mutex_unlock(&fs_devices->device_list_mutex);
6772
6773                 fs_devices = fs_devices->seed;
6774         }
6775 }
6776
6777 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
6778 {
6779         int i;
6780
6781         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6782                 btrfs_dev_stat_reset(dev, i);
6783 }
6784
6785 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
6786 {
6787         struct btrfs_key key;
6788         struct btrfs_key found_key;
6789         struct btrfs_root *dev_root = fs_info->dev_root;
6790         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6791         struct extent_buffer *eb;
6792         int slot;
6793         int ret = 0;
6794         struct btrfs_device *device;
6795         struct btrfs_path *path = NULL;
6796         int i;
6797
6798         path = btrfs_alloc_path();
6799         if (!path) {
6800                 ret = -ENOMEM;
6801                 goto out;
6802         }
6803
6804         mutex_lock(&fs_devices->device_list_mutex);
6805         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6806                 int item_size;
6807                 struct btrfs_dev_stats_item *ptr;
6808
6809                 key.objectid = 0;
6810                 key.type = BTRFS_DEV_STATS_KEY;
6811                 key.offset = device->devid;
6812                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
6813                 if (ret) {
6814                         __btrfs_reset_dev_stats(device);
6815                         device->dev_stats_valid = 1;
6816                         btrfs_release_path(path);
6817                         continue;
6818                 }
6819                 slot = path->slots[0];
6820                 eb = path->nodes[0];
6821                 btrfs_item_key_to_cpu(eb, &found_key, slot);
6822                 item_size = btrfs_item_size_nr(eb, slot);
6823
6824                 ptr = btrfs_item_ptr(eb, slot,
6825                                      struct btrfs_dev_stats_item);
6826
6827                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6828                         if (item_size >= (1 + i) * sizeof(__le64))
6829                                 btrfs_dev_stat_set(device, i,
6830                                         btrfs_dev_stats_value(eb, ptr, i));
6831                         else
6832                                 btrfs_dev_stat_reset(device, i);
6833                 }
6834
6835                 device->dev_stats_valid = 1;
6836                 btrfs_dev_stat_print_on_load(device);
6837                 btrfs_release_path(path);
6838         }
6839         mutex_unlock(&fs_devices->device_list_mutex);
6840
6841 out:
6842         btrfs_free_path(path);
6843         return ret < 0 ? ret : 0;
6844 }
6845
6846 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
6847                                 struct btrfs_root *dev_root,
6848                                 struct btrfs_device *device)
6849 {
6850         struct btrfs_path *path;
6851         struct btrfs_key key;
6852         struct extent_buffer *eb;
6853         struct btrfs_dev_stats_item *ptr;
6854         int ret;
6855         int i;
6856
6857         key.objectid = 0;
6858         key.type = BTRFS_DEV_STATS_KEY;
6859         key.offset = device->devid;
6860
6861         path = btrfs_alloc_path();
6862         BUG_ON(!path);
6863         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
6864         if (ret < 0) {
6865                 btrfs_warn_in_rcu(dev_root->fs_info,
6866                         "error %d while searching for dev_stats item for device %s",
6867                               ret, rcu_str_deref(device->name));
6868                 goto out;
6869         }
6870
6871         if (ret == 0 &&
6872             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
6873                 /* need to delete old one and insert a new one */
6874                 ret = btrfs_del_item(trans, dev_root, path);
6875                 if (ret != 0) {
6876                         btrfs_warn_in_rcu(dev_root->fs_info,
6877                                 "delete too small dev_stats item for device %s failed %d",
6878                                       rcu_str_deref(device->name), ret);
6879                         goto out;
6880                 }
6881                 ret = 1;
6882         }
6883
6884         if (ret == 1) {
6885                 /* need to insert a new item */
6886                 btrfs_release_path(path);
6887                 ret = btrfs_insert_empty_item(trans, dev_root, path,
6888                                               &key, sizeof(*ptr));
6889                 if (ret < 0) {
6890                         btrfs_warn_in_rcu(dev_root->fs_info,
6891                                 "insert dev_stats item for device %s failed %d",
6892                                 rcu_str_deref(device->name), ret);
6893                         goto out;
6894                 }
6895         }
6896
6897         eb = path->nodes[0];
6898         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
6899         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6900                 btrfs_set_dev_stats_value(eb, ptr, i,
6901                                           btrfs_dev_stat_read(device, i));
6902         btrfs_mark_buffer_dirty(eb);
6903
6904 out:
6905         btrfs_free_path(path);
6906         return ret;
6907 }
6908
6909 /*
6910  * called from commit_transaction. Writes all changed device stats to disk.
6911  */
6912 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
6913                         struct btrfs_fs_info *fs_info)
6914 {
6915         struct btrfs_root *dev_root = fs_info->dev_root;
6916         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6917         struct btrfs_device *device;
6918         int stats_cnt;
6919         int ret = 0;
6920
6921         mutex_lock(&fs_devices->device_list_mutex);
6922         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6923                 if (!device->dev_stats_valid || !btrfs_dev_stats_dirty(device))
6924                         continue;
6925
6926                 stats_cnt = atomic_read(&device->dev_stats_ccnt);
6927                 ret = update_dev_stat_item(trans, dev_root, device);
6928                 if (!ret)
6929                         atomic_sub(stats_cnt, &device->dev_stats_ccnt);
6930         }
6931         mutex_unlock(&fs_devices->device_list_mutex);
6932
6933         return ret;
6934 }
6935
6936 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
6937 {
6938         btrfs_dev_stat_inc(dev, index);
6939         btrfs_dev_stat_print_on_error(dev);
6940 }
6941
6942 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
6943 {
6944         if (!dev->dev_stats_valid)
6945                 return;
6946         btrfs_err_rl_in_rcu(dev->dev_root->fs_info,
6947                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
6948                            rcu_str_deref(dev->name),
6949                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
6950                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
6951                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
6952                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
6953                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
6954 }
6955
6956 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
6957 {
6958         int i;
6959
6960         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6961                 if (btrfs_dev_stat_read(dev, i) != 0)
6962                         break;
6963         if (i == BTRFS_DEV_STAT_VALUES_MAX)
6964                 return; /* all values == 0, suppress message */
6965
6966         btrfs_info_in_rcu(dev->dev_root->fs_info,
6967                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
6968                rcu_str_deref(dev->name),
6969                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
6970                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
6971                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
6972                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
6973                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
6974 }
6975
6976 int btrfs_get_dev_stats(struct btrfs_root *root,
6977                         struct btrfs_ioctl_get_dev_stats *stats)
6978 {
6979         struct btrfs_device *dev;
6980         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6981         int i;
6982
6983         mutex_lock(&fs_devices->device_list_mutex);
6984         dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
6985         mutex_unlock(&fs_devices->device_list_mutex);
6986
6987         if (!dev) {
6988                 btrfs_warn(root->fs_info, "get dev_stats failed, device not found");
6989                 return -ENODEV;
6990         } else if (!dev->dev_stats_valid) {
6991                 btrfs_warn(root->fs_info, "get dev_stats failed, not yet valid");
6992                 return -ENODEV;
6993         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
6994                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6995                         if (stats->nr_items > i)
6996                                 stats->values[i] =
6997                                         btrfs_dev_stat_read_and_reset(dev, i);
6998                         else
6999                                 btrfs_dev_stat_reset(dev, i);
7000                 }
7001         } else {
7002                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
7003                         if (stats->nr_items > i)
7004                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
7005         }
7006         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
7007                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
7008         return 0;
7009 }
7010
7011 void btrfs_scratch_superblocks(struct block_device *bdev, char *device_path)
7012 {
7013         struct buffer_head *bh;
7014         struct btrfs_super_block *disk_super;
7015         int copy_num;
7016
7017         if (!bdev)
7018                 return;
7019
7020         for (copy_num = 0; copy_num < BTRFS_SUPER_MIRROR_MAX;
7021                 copy_num++) {
7022
7023                 if (btrfs_read_dev_one_super(bdev, copy_num, &bh))
7024                         continue;
7025
7026                 disk_super = (struct btrfs_super_block *)bh->b_data;
7027
7028                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
7029                 set_buffer_dirty(bh);
7030                 sync_dirty_buffer(bh);
7031                 brelse(bh);
7032         }
7033
7034         /* Notify udev that device has changed */
7035         btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
7036
7037         /* Update ctime/mtime for device path for libblkid */
7038         update_dev_time(device_path);
7039 }
7040
7041 /*
7042  * Update the size of all devices, which is used for writing out the
7043  * super blocks.
7044  */
7045 void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info)
7046 {
7047         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
7048         struct btrfs_device *curr, *next;
7049
7050         if (list_empty(&fs_devices->resized_devices))
7051                 return;
7052
7053         mutex_lock(&fs_devices->device_list_mutex);
7054         lock_chunks(fs_info->dev_root);
7055         list_for_each_entry_safe(curr, next, &fs_devices->resized_devices,
7056                                  resized_list) {
7057                 list_del_init(&curr->resized_list);
7058                 curr->commit_total_bytes = curr->disk_total_bytes;
7059         }
7060         unlock_chunks(fs_info->dev_root);
7061         mutex_unlock(&fs_devices->device_list_mutex);
7062 }
7063
7064 /* Must be invoked during the transaction commit */
7065 void btrfs_update_commit_device_bytes_used(struct btrfs_root *root,
7066                                         struct btrfs_transaction *transaction)
7067 {
7068         struct extent_map *em;
7069         struct map_lookup *map;
7070         struct btrfs_device *dev;
7071         int i;
7072
7073         if (list_empty(&transaction->pending_chunks))
7074                 return;
7075
7076         /* In order to kick the device replace finish process */
7077         lock_chunks(root);
7078         list_for_each_entry(em, &transaction->pending_chunks, list) {
7079                 map = em->map_lookup;
7080
7081                 for (i = 0; i < map->num_stripes; i++) {
7082                         dev = map->stripes[i].dev;
7083                         dev->commit_bytes_used = dev->bytes_used;
7084                         dev->has_pending_chunks = false;
7085                 }
7086         }
7087         unlock_chunks(root);
7088 }
7089
7090 void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info)
7091 {
7092         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
7093         while (fs_devices) {
7094                 fs_devices->fs_info = fs_info;
7095                 fs_devices = fs_devices->seed;
7096         }
7097 }
7098
7099 void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info)
7100 {
7101         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
7102         while (fs_devices) {
7103                 fs_devices->fs_info = NULL;
7104                 fs_devices = fs_devices->seed;
7105         }
7106 }
7107
7108 void btrfs_close_one_device(struct btrfs_device *device)
7109 {
7110         struct btrfs_fs_devices *fs_devices = device->fs_devices;
7111         struct btrfs_device *new_device;
7112         struct rcu_string *name;
7113
7114         if (device->bdev)
7115                 fs_devices->open_devices--;
7116
7117         if (device->writeable &&
7118             device->devid != BTRFS_DEV_REPLACE_DEVID) {
7119                 list_del_init(&device->dev_alloc_list);
7120                 fs_devices->rw_devices--;
7121         }
7122
7123         if (device->missing)
7124                 fs_devices->missing_devices--;
7125
7126         new_device = btrfs_alloc_device(NULL, &device->devid,
7127                                         device->uuid);
7128         BUG_ON(IS_ERR(new_device)); /* -ENOMEM */
7129
7130         /* Safe because we are under uuid_mutex */
7131         if (device->name) {
7132                 name = rcu_string_strdup(device->name->str, GFP_NOFS);
7133                 BUG_ON(!name); /* -ENOMEM */
7134                 rcu_assign_pointer(new_device->name, name);
7135         }
7136
7137         list_replace_rcu(&device->dev_list, &new_device->dev_list);
7138         new_device->fs_devices = device->fs_devices;
7139
7140         call_rcu(&device->rcu, free_device);
7141 }