log.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   4  * Copyright (C) 2004-2007 Red Hat, Inc.  All rights reserved.
   5  */
   6
   7 #include <linux/sched.h>
   8 #include <linux/slab.h>
   9 #include <linux/spinlock.h>
  10 #include <linux/completion.h>
  11 #include <linux/buffer_head.h>
  12 #include <linux/gfs2_ondisk.h>
  13 #include <linux/crc32.h>
  14 #include <linux/crc32c.h>
  15 #include <linux/delay.h>
  16 #include <linux/kthread.h>
  17 #include <linux/freezer.h>
  18 #include <linux/bio.h>
  19 #include <linux/blkdev.h>
  20 #include <linux/writeback.h>
  21 #include <linux/list_sort.h>
  22
  23 #include "gfs2.h"
  24 #include "incore.h"
  25 #include "bmap.h"
  26 #include "glock.h"
  27 #include "log.h"
  28 #include "lops.h"
  29 #include "meta_io.h"
  30 #include "util.h"
  31 #include "dir.h"
  32 #include "trace_gfs2.h"
  33 #include "trans.h"
  34
  35 static void gfs2_log_shutdown(struct gfs2_sbd *sdp);
  36
  37 /**
  38  * gfs2_struct2blk - compute stuff
  39  * @sdp: the filesystem
  40  * @nstruct: the number of structures
  41  *
  42  * Compute the number of log descriptor blocks needed to hold a certain number
  43  * of structures of a certain size.
  44  *
  45  * Returns: the number of blocks needed (minimum is always 1)
  46  */
  47
  48 unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct)
  49 {
  50         unsigned int blks;
  51         unsigned int first, second;
  52
  53         /* The initial struct gfs2_log_descriptor block */
  54         blks = 1;
  55         first = sdp->sd_ldptrs;
  56
  57         if (nstruct > first) {
  58                 /* Subsequent struct gfs2_meta_header blocks */
  59                 second = sdp->sd_inptrs;
  60                 blks += DIV_ROUND_UP(nstruct - first, second);
  61         }
  62
  63         return blks;
  64 }
  65
  66 /**
  67  * gfs2_remove_from_ail - Remove an entry from the ail lists, updating counters
  68  * @bd: The gfs2_bufdata to remove
  69  *
  70  * The ail lock _must_ be held when calling this function
  71  *
  72  */
  73
  74 void gfs2_remove_from_ail(struct gfs2_bufdata *bd)
  75 {
  76         bd->bd_tr = NULL;
  77         list_del_init(&bd->bd_ail_st_list);
  78         list_del_init(&bd->bd_ail_gl_list);
  79         atomic_dec(&bd->bd_gl->gl_ail_count);
  80         brelse(bd->bd_bh);
  81 }
  82
  83 static int __gfs2_writepage(struct page *page, struct writeback_control *wbc,
  84                        void *data)
  85 {
  86         struct address_space *mapping = data;
  87         int ret = mapping->a_ops->writepage(page, wbc);
  88         mapping_set_error(mapping, ret);
  89         return ret;
  90 }
  91
  92 /**
  93  * gfs2_ail1_start_one - Start I/O on a transaction
  94  * @sdp: The superblock
  95  * @wbc: The writeback control structure
  96  * @tr: The transaction to start I/O on
  97  * @plug: The block plug currently active
  98  */
  99
 100 static int gfs2_ail1_start_one(struct gfs2_sbd *sdp,
 101                                struct writeback_control *wbc,
 102                                struct gfs2_trans *tr, struct blk_plug *plug)
 103 __releases(&sdp->sd_ail_lock)
 104 __acquires(&sdp->sd_ail_lock)
 105 {
 106         struct gfs2_glock *gl = NULL;
 107         struct address_space *mapping;
 108         struct gfs2_bufdata *bd, *s;
 109         struct buffer_head *bh;
 110         int ret = 0;
 111
 112         list_for_each_entry_safe_reverse(bd, s, &tr->tr_ail1_list, bd_ail_st_list) {
 113                 bh = bd->bd_bh;
 114
 115                 gfs2_assert(sdp, bd->bd_tr == tr);
 116
 117                 if (!buffer_busy(bh)) {
 118                         if (buffer_uptodate(bh)) {
 119                                 list_move(&bd->bd_ail_st_list,
 120                                           &tr->tr_ail2_list);
 121                                 continue;
 122                         }
 123                         if (!cmpxchg(&sdp->sd_log_error, 0, -EIO)) {
 124                                 gfs2_io_error_bh(sdp, bh);
 125                                 gfs2_withdraw_delayed(sdp);
 126                         }
 127                 }
 128
 129                 if (gfs2_withdrawn(sdp)) {
 130                         gfs2_remove_from_ail(bd);
 131                         continue;
 132                 }
 133                 if (!buffer_dirty(bh))
 134                         continue;
 135                 if (gl == bd->bd_gl)
 136                         continue;
 137                 gl = bd->bd_gl;
 138                 list_move(&bd->bd_ail_st_list, &tr->tr_ail1_list);
 139                 mapping = bh->b_page->mapping;
 140                 if (!mapping)
 141                         continue;
 142                 spin_unlock(&sdp->sd_ail_lock);
 143                 ret = write_cache_pages(mapping, wbc, __gfs2_writepage, mapping);
 144                 if (need_resched()) {
 145                         blk_finish_plug(plug);
 146                         cond_resched();
 147                         blk_start_plug(plug);
 148                 }
 149                 spin_lock(&sdp->sd_ail_lock);
 150                 if (ret == -ENODATA) /* if a jdata write into a new hole */
 151                         ret = 0; /* ignore it */
 152                 if (ret || wbc->nr_to_write <= 0)
 153                         break;
 154                 return -EBUSY;
 155         }
 156
 157         return ret;
 158 }
 159
 160 static void dump_ail_list(struct gfs2_sbd *sdp)
 161 {
 162         struct gfs2_trans *tr;
 163         struct gfs2_bufdata *bd;
 164         struct buffer_head *bh;
 165
 166         list_for_each_entry_reverse(tr, &sdp->sd_ail1_list, tr_list) {
 167                 list_for_each_entry_reverse(bd, &tr->tr_ail1_list,
 168                                             bd_ail_st_list) {
 169                         bh = bd->bd_bh;
 170                         fs_err(sdp, "bd %p: blk:0x%llx bh=%p ", bd,
 171                                (unsigned long long)bd->bd_blkno, bh);
 172                         if (!bh) {
 173                                 fs_err(sdp, "\n");
 174                                 continue;
 175                         }
 176                         fs_err(sdp, "0x%llx up2:%d dirt:%d lkd:%d req:%d "
 177                                "map:%d new:%d ar:%d aw:%d delay:%d "
 178                                "io err:%d unwritten:%d dfr:%d pin:%d esc:%d\n",
 179                                (unsigned long long)bh->b_blocknr,
 180                                buffer_uptodate(bh), buffer_dirty(bh),
 181                                buffer_locked(bh), buffer_req(bh),
 182                                buffer_mapped(bh), buffer_new(bh),
 183                                buffer_async_read(bh), buffer_async_write(bh),
 184                                buffer_delay(bh), buffer_write_io_error(bh),
 185                                buffer_unwritten(bh),
 186                                buffer_defer_completion(bh),
 187                                buffer_pinned(bh), buffer_escaped(bh));
 188                 }
 189         }
 190 }
 191
 192 /**
 193  * gfs2_ail1_flush - start writeback of some ail1 entries
 194  * @sdp: The super block
 195  * @wbc: The writeback control structure
 196  *
 197  * Writes back some ail1 entries, according to the limits in the
 198  * writeback control structure
 199  */
 200
 201 void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc)
 202 {
 203         struct list_head *head = &sdp->sd_ail1_list;
 204         struct gfs2_trans *tr;
 205         struct blk_plug plug;
 206         int ret;
 207         unsigned long flush_start = jiffies;
 208
 209         trace_gfs2_ail_flush(sdp, wbc, 1);
 210         blk_start_plug(&plug);
 211         spin_lock(&sdp->sd_ail_lock);
 212 restart:
 213         ret = 0;
 214         if (time_after(jiffies, flush_start + (HZ * 600))) {
 215                 fs_err(sdp, "Error: In %s for ten minutes! t=%d\n",
 216                        __func__, current->journal_info ? 1 : 0);
 217                 dump_ail_list(sdp);
 218                 goto out;
 219         }
 220         list_for_each_entry_reverse(tr, head, tr_list) {
 221                 if (wbc->nr_to_write <= 0)
 222                         break;
 223                 ret = gfs2_ail1_start_one(sdp, wbc, tr, &plug);
 224                 if (ret) {
 225                         if (ret == -EBUSY)
 226                                 goto restart;
 227                         break;
 228                 }
 229         }
 230 out:
 231         spin_unlock(&sdp->sd_ail_lock);
 232         blk_finish_plug(&plug);
 233         if (ret) {
 234                 gfs2_lm(sdp, "gfs2_ail1_start_one returned: %d\n", ret);
 235                 gfs2_withdraw(sdp);
 236         }
 237         trace_gfs2_ail_flush(sdp, wbc, 0);
 238 }
 239
 240 /**
 241  * gfs2_ail1_start - start writeback of all ail1 entries
 242  * @sdp: The superblock
 243  */
 244
 245 static void gfs2_ail1_start(struct gfs2_sbd *sdp)
 246 {
 247         struct writeback_control wbc = {
 248                 .sync_mode = WB_SYNC_NONE,
 249                 .nr_to_write = LONG_MAX,
 250                 .range_start = 0,
 251                 .range_end = LLONG_MAX,
 252         };
 253
 254         return gfs2_ail1_flush(sdp, &wbc);
 255 }
 256
 257 static void gfs2_log_update_flush_tail(struct gfs2_sbd *sdp)
 258 {
 259         unsigned int new_flush_tail = sdp->sd_log_head;
 260         struct gfs2_trans *tr;
 261
 262         if (!list_empty(&sdp->sd_ail1_list)) {
 263                 tr = list_last_entry(&sdp->sd_ail1_list,
 264                                      struct gfs2_trans, tr_list);
 265                 new_flush_tail = tr->tr_first;
 266         }
 267         sdp->sd_log_flush_tail = new_flush_tail;
 268 }
 269
 270 static void gfs2_log_update_head(struct gfs2_sbd *sdp)
 271 {
 272         unsigned int new_head = sdp->sd_log_flush_head;
 273
 274         if (sdp->sd_log_flush_tail == sdp->sd_log_head)
 275                 sdp->sd_log_flush_tail = new_head;
 276         sdp->sd_log_head = new_head;
 277 }
 278
 279 /*
 280  * gfs2_ail_empty_tr - empty one of the ail lists of a transaction
 281  */
 282
 283 static void gfs2_ail_empty_tr(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
 284                               struct list_head *head)
 285 {
 286         struct gfs2_bufdata *bd;
 287
 288         while (!list_empty(head)) {
 289                 bd = list_first_entry(head, struct gfs2_bufdata,
 290                                       bd_ail_st_list);
 291                 gfs2_assert(sdp, bd->bd_tr == tr);
 292                 gfs2_remove_from_ail(bd);
 293         }
 294 }
 295
 296 /**
 297  * gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
 298  * @sdp: the filesystem
 299  * @tr: the transaction
 300  * @max_revokes: If nonzero, issue revokes for the bd items for written buffers
 301  *
 302  * returns: the transaction's count of remaining active items
 303  */
 304
 305 static int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
 306                                 int *max_revokes)
 307 {
 308         struct gfs2_bufdata *bd, *s;
 309         struct buffer_head *bh;
 310         int active_count = 0;
 311
 312         list_for_each_entry_safe_reverse(bd, s, &tr->tr_ail1_list,
 313                                          bd_ail_st_list) {
 314                 bh = bd->bd_bh;
 315                 gfs2_assert(sdp, bd->bd_tr == tr);
 316                 /*
 317                  * If another process flagged an io error, e.g. writing to the
 318                  * journal, error all other bhs and move them off the ail1 to
 319                  * prevent a tight loop when unmount tries to flush ail1,
 320                  * regardless of whether they're still busy. If no outside
 321                  * errors were found and the buffer is busy, move to the next.
 322                  * If the ail buffer is not busy and caught an error, flag it
 323                  * for others.
 324                  */
 325                 if (!sdp->sd_log_error && buffer_busy(bh)) {
 326                         active_count++;
 327                         continue;
 328                 }
 329                 if (!buffer_uptodate(bh) &&
 330                     !cmpxchg(&sdp->sd_log_error, 0, -EIO)) {
 331                         gfs2_io_error_bh(sdp, bh);
 332                         gfs2_withdraw_delayed(sdp);
 333                 }
 334                 /*
 335                  * If we have space for revokes and the bd is no longer on any
 336                  * buf list, we can just add a revoke for it immediately and
 337                  * avoid having to put it on the ail2 list, where it would need
 338                  * to be revoked later.
 339                  */
 340                 if (*max_revokes && list_empty(&bd->bd_list)) {
 341                         gfs2_add_revoke(sdp, bd);
 342                         (*max_revokes)--;
 343                         continue;
 344                 }
 345                 list_move(&bd->bd_ail_st_list, &tr->tr_ail2_list);
 346         }
 347         return active_count;
 348 }
 349
 350 /**
 351  * gfs2_ail1_empty - Try to empty the ail1 lists
 352  * @sdp: The superblock
 353  * @max_revokes: If non-zero, add revokes where appropriate
 354  *
 355  * Tries to empty the ail1 lists, starting with the oldest first
 356  */
 357
 358 static int gfs2_ail1_empty(struct gfs2_sbd *sdp, int max_revokes)
 359 {
 360         struct gfs2_trans *tr, *s;
 361         int oldest_tr = 1;
 362         int ret;
 363
 364         spin_lock(&sdp->sd_ail_lock);
 365         list_for_each_entry_safe_reverse(tr, s, &sdp->sd_ail1_list, tr_list) {
 366                 if (!gfs2_ail1_empty_one(sdp, tr, &max_revokes) && oldest_tr)
 367                         list_move(&tr->tr_list, &sdp->sd_ail2_list);
 368                 else
 369                         oldest_tr = 0;
 370         }
 371         gfs2_log_update_flush_tail(sdp);
 372         ret = list_empty(&sdp->sd_ail1_list);
 373         spin_unlock(&sdp->sd_ail_lock);
 374
 375         if (test_bit(SDF_WITHDRAWING, &sdp->sd_flags)) {
 376                 gfs2_lm(sdp, "fatal: I/O error(s)\n");
 377                 gfs2_withdraw(sdp);
 378         }
 379
 380         return ret;
 381 }
 382
 383 static void gfs2_ail1_wait(struct gfs2_sbd *sdp)
 384 {
 385         struct gfs2_trans *tr;
 386         struct gfs2_bufdata *bd;
 387         struct buffer_head *bh;
 388
 389         spin_lock(&sdp->sd_ail_lock);
 390         list_for_each_entry_reverse(tr, &sdp->sd_ail1_list, tr_list) {
 391                 list_for_each_entry(bd, &tr->tr_ail1_list, bd_ail_st_list) {
 392                         bh = bd->bd_bh;
 393                         if (!buffer_locked(bh))
 394                                 continue;
 395                         get_bh(bh);
 396                         spin_unlock(&sdp->sd_ail_lock);
 397                         wait_on_buffer(bh);
 398                         brelse(bh);
 399                         return;
 400                 }
 401         }
 402         spin_unlock(&sdp->sd_ail_lock);
 403 }
 404
 405 static void __ail2_empty(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 406 {
 407         gfs2_ail_empty_tr(sdp, tr, &tr->tr_ail2_list);
 408         list_del(&tr->tr_list);
 409         gfs2_assert_warn(sdp, list_empty(&tr->tr_ail1_list));
 410         gfs2_assert_warn(sdp, list_empty(&tr->tr_ail2_list));
 411         gfs2_trans_free(sdp, tr);
 412 }
 413
 414 static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
 415 {
 416         struct list_head *ail2_list = &sdp->sd_ail2_list;
 417         unsigned int old_tail = sdp->sd_log_tail;
 418         struct gfs2_trans *tr, *safe;
 419
 420         spin_lock(&sdp->sd_ail_lock);
 421         if (old_tail <= new_tail) {
 422                 list_for_each_entry_safe(tr, safe, ail2_list, tr_list) {
 423                         if (old_tail <= tr->tr_first && tr->tr_first < new_tail)
 424                                 __ail2_empty(sdp, tr);
 425                 }
 426         } else {
 427                 list_for_each_entry_safe(tr, safe, ail2_list, tr_list) {
 428                         if (old_tail <= tr->tr_first || tr->tr_first < new_tail)
 429                                 __ail2_empty(sdp, tr);
 430                 }
 431         }
 432         spin_unlock(&sdp->sd_ail_lock);
 433 }
 434
 435 /**
 436  * gfs2_log_is_empty - Check if the log is empty
 437  * @sdp: The GFS2 superblock
 438  */
 439
 440 bool gfs2_log_is_empty(struct gfs2_sbd *sdp) {
 441         return atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks;
 442 }
 443
 444 static bool __gfs2_log_try_reserve_revokes(struct gfs2_sbd *sdp, unsigned int revokes)
 445 {
 446         unsigned int available;
 447
 448         available = atomic_read(&sdp->sd_log_revokes_available);
 449         while (available >= revokes) {
 450                 if (atomic_try_cmpxchg(&sdp->sd_log_revokes_available,
 451                                        &available, available - revokes))
 452                         return true;
 453         }
 454         return false;
 455 }
 456
 457 /**
 458  * gfs2_log_release_revokes - Release a given number of revokes
 459  * @sdp: The GFS2 superblock
 460  * @revokes: The number of revokes to release
 461  *
 462  * sdp->sd_log_flush_lock must be held.
 463  */
 464 void gfs2_log_release_revokes(struct gfs2_sbd *sdp, unsigned int revokes)
 465 {
 466         if (revokes)
 467                 atomic_add(revokes, &sdp->sd_log_revokes_available);
 468 }
 469
 470 /**
 471  * gfs2_log_release - Release a given number of log blocks
 472  * @sdp: The GFS2 superblock
 473  * @blks: The number of blocks
 474  *
 475  */
 476
 477 void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
 478 {
 479         atomic_add(blks, &sdp->sd_log_blks_free);
 480         trace_gfs2_log_blocks(sdp, blks);
 481         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 482                                   sdp->sd_jdesc->jd_blocks);
 483         if (atomic_read(&sdp->sd_log_blks_needed))
 484                 wake_up(&sdp->sd_log_waitq);
 485 }
 486
 487 /**
 488  * __gfs2_log_try_reserve - Try to make a log reservation
 489  * @sdp: The GFS2 superblock
 490  * @blks: The number of blocks to reserve
 491  * @taboo_blks: The number of blocks to leave free
 492  *
 493  * Try to do the same as __gfs2_log_reserve(), but fail if no more log
 494  * space is immediately available.
 495  */
 496 static bool __gfs2_log_try_reserve(struct gfs2_sbd *sdp, unsigned int blks,
 497                                    unsigned int taboo_blks)
 498 {
 499         unsigned wanted = blks + taboo_blks;
 500         unsigned int free_blocks;
 501
 502         free_blocks = atomic_read(&sdp->sd_log_blks_free);
 503         while (free_blocks >= wanted) {
 504                 if (atomic_try_cmpxchg(&sdp->sd_log_blks_free, &free_blocks,
 505                                        free_blocks - blks)) {
 506                         trace_gfs2_log_blocks(sdp, -blks);
 507                         return true;
 508                 }
 509         }
 510         return false;
 511 }
 512
 513 /**
 514  * __gfs2_log_reserve - Make a log reservation
 515  * @sdp: The GFS2 superblock
 516  * @blks: The number of blocks to reserve
 517  * @taboo_blks: The number of blocks to leave free
 518  *
 519  * @taboo_blks is set to 0 for logd, and to GFS2_LOG_FLUSH_MIN_BLOCKS
 520  * for all other processes.  This ensures that when the log is almost full,
 521  * logd will still be able to call gfs2_log_flush one more time  without
 522  * blocking, which will advance the tail and make some more log space
 523  * available.
 524  *
 525  * We no longer flush the log here, instead we wake up logd to do that
 526  * for us. To avoid the thundering herd and to ensure that we deal fairly
 527  * with queued waiters, we use an exclusive wait. This means that when we
 528  * get woken with enough journal space to get our reservation, we need to
 529  * wake the next waiter on the list.
 530  */
 531
 532 static void __gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks,
 533                                unsigned int taboo_blks)
 534 {
 535         unsigned wanted = blks + taboo_blks;
 536         unsigned int free_blocks;
 537
 538         atomic_add(blks, &sdp->sd_log_blks_needed);
 539         for (;;) {
 540                 if (current != sdp->sd_logd_process)
 541                         wake_up(&sdp->sd_logd_waitq);
 542                 io_wait_event(sdp->sd_log_waitq,
 543                         (free_blocks = atomic_read(&sdp->sd_log_blks_free),
 544                          free_blocks >= wanted));
 545                 do {
 546                         if (atomic_try_cmpxchg(&sdp->sd_log_blks_free,
 547                                                &free_blocks,
 548                                                free_blocks - blks))
 549                                 goto reserved;
 550                 } while (free_blocks >= wanted);
 551         }
 552
 553 reserved:
 554         trace_gfs2_log_blocks(sdp, -blks);
 555         if (atomic_sub_return(blks, &sdp->sd_log_blks_needed))
 556                 wake_up(&sdp->sd_log_waitq);
 557 }
 558
 559 /**
 560  * gfs2_log_try_reserve - Try to make a log reservation
 561  * @sdp: The GFS2 superblock
 562  * @tr: The transaction
 563  * @extra_revokes: The number of additional revokes reserved (output)
 564  *
 565  * This is similar to gfs2_log_reserve, but sdp->sd_log_flush_lock must be
 566  * held for correct revoke accounting.
 567  */
 568
 569 bool gfs2_log_try_reserve(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
 570                           unsigned int *extra_revokes)
 571 {
 572         unsigned int blks = tr->tr_reserved;
 573         unsigned int revokes = tr->tr_revokes;
 574         unsigned int revoke_blks = 0;
 575
 576         *extra_revokes = 0;
 577         if (revokes && !__gfs2_log_try_reserve_revokes(sdp, revokes)) {
 578                 revoke_blks = DIV_ROUND_UP(revokes, sdp->sd_inptrs);
 579                 *extra_revokes = revoke_blks * sdp->sd_inptrs - revokes;
 580                 blks += revoke_blks;
 581         }
 582         if (!blks)
 583                 return true;
 584         if (__gfs2_log_try_reserve(sdp, blks, GFS2_LOG_FLUSH_MIN_BLOCKS))
 585                 return true;
 586         if (!revoke_blks)
 587                 gfs2_log_release_revokes(sdp, revokes);
 588         return false;
 589 }
 590
 591 /**
 592  * gfs2_log_reserve - Make a log reservation
 593  * @sdp: The GFS2 superblock
 594  * @tr: The transaction
 595  * @extra_revokes: The number of additional revokes reserved (output)
 596  *
 597  * sdp->sd_log_flush_lock must not be held.
 598  */
 599
 600 void gfs2_log_reserve(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
 601                       unsigned int *extra_revokes)
 602 {
 603         unsigned int blks = tr->tr_reserved;
 604         unsigned int revokes = tr->tr_revokes;
 605         unsigned int revoke_blks;
 606
 607         *extra_revokes = 0;
 608         if (revokes) {
 609                 revoke_blks = DIV_ROUND_UP(revokes, sdp->sd_inptrs);
 610                 *extra_revokes = revoke_blks * sdp->sd_inptrs - revokes;
 611                 blks += revoke_blks;
 612         }
 613         __gfs2_log_reserve(sdp, blks, GFS2_LOG_FLUSH_MIN_BLOCKS);
 614 }
 615
 616 /**
 617  * log_distance - Compute distance between two journal blocks
 618  * @sdp: The GFS2 superblock
 619  * @newer: The most recent journal block of the pair
 620  * @older: The older journal block of the pair
 621  *
 622  *   Compute the distance (in the journal direction) between two
 623  *   blocks in the journal
 624  *
 625  * Returns: the distance in blocks
 626  */
 627
 628 static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer,
 629                                         unsigned int older)
 630 {
 631         int dist;
 632
 633         dist = newer - older;
 634         if (dist < 0)
 635                 dist += sdp->sd_jdesc->jd_blocks;
 636
 637         return dist;
 638 }
 639
 640 /**
 641  * calc_reserved - Calculate the number of blocks to keep reserved
 642  * @sdp: The GFS2 superblock
 643  *
 644  * This is complex.  We need to reserve room for all our currently used
 645  * metadata blocks (e.g. normal file I/O rewriting file time stamps) and
 646  * all our journaled data blocks for journaled files (e.g. files in the
 647  * meta_fs like rindex, or files for which chattr +j was done.)
 648  * If we don't reserve enough space, corruption will follow.
 649  *
 650  * We can have metadata blocks and jdata blocks in the same journal.  Each
 651  * type gets its own log descriptor, for which we need to reserve a block.
 652  * In fact, each type has the potential for needing more than one log descriptor
 653  * in cases where we have more blocks than will fit in a log descriptor.
 654  * Metadata journal entries take up half the space of journaled buffer entries.
 655  *
 656  * Also, we need to reserve blocks for revoke journal entries and one for an
 657  * overall header for the lot.
 658  *
 659  * Returns: the number of blocks reserved
 660  */
 661 static unsigned int calc_reserved(struct gfs2_sbd *sdp)
 662 {
 663         unsigned int reserved = GFS2_LOG_FLUSH_MIN_BLOCKS;
 664         unsigned int blocks;
 665         struct gfs2_trans *tr = sdp->sd_log_tr;
 666
 667         if (tr) {
 668                 blocks = tr->tr_num_buf_new - tr->tr_num_buf_rm;
 669                 reserved += blocks + DIV_ROUND_UP(blocks, buf_limit(sdp));
 670                 blocks = tr->tr_num_databuf_new - tr->tr_num_databuf_rm;
 671                 reserved += blocks + DIV_ROUND_UP(blocks, databuf_limit(sdp));
 672         }
 673         return reserved;
 674 }
 675
 676 static void log_pull_tail(struct gfs2_sbd *sdp)
 677 {
 678         unsigned int new_tail = sdp->sd_log_flush_tail;
 679         unsigned int dist;
 680
 681         if (new_tail == sdp->sd_log_tail)
 682                 return;
 683         dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
 684         ail2_empty(sdp, new_tail);
 685         gfs2_log_release(sdp, dist);
 686         sdp->sd_log_tail = new_tail;
 687 }
 688
 689
 690 void log_flush_wait(struct gfs2_sbd *sdp)
 691 {
 692         DEFINE_WAIT(wait);
 693
 694         if (atomic_read(&sdp->sd_log_in_flight)) {
 695                 do {
 696                         prepare_to_wait(&sdp->sd_log_flush_wait, &wait,
 697                                         TASK_UNINTERRUPTIBLE);
 698                         if (atomic_read(&sdp->sd_log_in_flight))
 699                                 io_schedule();
 700                 } while(atomic_read(&sdp->sd_log_in_flight));
 701                 finish_wait(&sdp->sd_log_flush_wait, &wait);
 702         }
 703 }
 704
 705 static int ip_cmp(void *priv, const struct list_head *a, const struct list_head *b)
 706 {
 707         struct gfs2_inode *ipa, *ipb;
 708
 709         ipa = list_entry(a, struct gfs2_inode, i_ordered);
 710         ipb = list_entry(b, struct gfs2_inode, i_ordered);
 711
 712         if (ipa->i_no_addr < ipb->i_no_addr)
 713                 return -1;
 714         if (ipa->i_no_addr > ipb->i_no_addr)
 715                 return 1;
 716         return 0;
 717 }
 718
 719 static void __ordered_del_inode(struct gfs2_inode *ip)
 720 {
 721         if (!list_empty(&ip->i_ordered))
 722                 list_del_init(&ip->i_ordered);
 723 }
 724
 725 static void gfs2_ordered_write(struct gfs2_sbd *sdp)
 726 {
 727         struct gfs2_inode *ip;
 728         LIST_HEAD(written);
 729
 730         spin_lock(&sdp->sd_ordered_lock);
 731         list_sort(NULL, &sdp->sd_log_ordered, &ip_cmp);
 732         while (!list_empty(&sdp->sd_log_ordered)) {
 733                 ip = list_first_entry(&sdp->sd_log_ordered, struct gfs2_inode, i_ordered);
 734                 if (ip->i_inode.i_mapping->nrpages == 0) {
 735                         __ordered_del_inode(ip);
 736                         continue;
 737                 }
 738                 list_move(&ip->i_ordered, &written);
 739                 spin_unlock(&sdp->sd_ordered_lock);
 740                 filemap_fdatawrite(ip->i_inode.i_mapping);
 741                 spin_lock(&sdp->sd_ordered_lock);
 742         }
 743         list_splice(&written, &sdp->sd_log_ordered);
 744         spin_unlock(&sdp->sd_ordered_lock);
 745 }
 746
 747 static void gfs2_ordered_wait(struct gfs2_sbd *sdp)
 748 {
 749         struct gfs2_inode *ip;
 750
 751         spin_lock(&sdp->sd_ordered_lock);
 752         while (!list_empty(&sdp->sd_log_ordered)) {
 753                 ip = list_first_entry(&sdp->sd_log_ordered, struct gfs2_inode, i_ordered);
 754                 __ordered_del_inode(ip);
 755                 if (ip->i_inode.i_mapping->nrpages == 0)
 756                         continue;
 757                 spin_unlock(&sdp->sd_ordered_lock);
 758                 filemap_fdatawait(ip->i_inode.i_mapping);
 759                 spin_lock(&sdp->sd_ordered_lock);
 760         }
 761         spin_unlock(&sdp->sd_ordered_lock);
 762 }
 763
 764 void gfs2_ordered_del_inode(struct gfs2_inode *ip)
 765 {
 766         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 767
 768         spin_lock(&sdp->sd_ordered_lock);
 769         __ordered_del_inode(ip);
 770         spin_unlock(&sdp->sd_ordered_lock);
 771 }
 772
 773 void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 774 {
 775         struct buffer_head *bh = bd->bd_bh;
 776         struct gfs2_glock *gl = bd->bd_gl;
 777
 778         sdp->sd_log_num_revoke++;
 779         if (atomic_inc_return(&gl->gl_revokes) == 1)
 780                 gfs2_glock_hold(gl);
 781         bh->b_private = NULL;
 782         bd->bd_blkno = bh->b_blocknr;
 783         gfs2_remove_from_ail(bd); /* drops ref on bh */
 784         bd->bd_bh = NULL;
 785         set_bit(GLF_LFLUSH, &gl->gl_flags);
 786         list_add(&bd->bd_list, &sdp->sd_log_revokes);
 787 }
 788
 789 void gfs2_glock_remove_revoke(struct gfs2_glock *gl)
 790 {
 791         if (atomic_dec_return(&gl->gl_revokes) == 0) {
 792                 clear_bit(GLF_LFLUSH, &gl->gl_flags);
 793                 gfs2_glock_queue_put(gl);
 794         }
 795 }
 796
 797 /**
 798  * gfs2_flush_revokes - Add as many revokes to the system transaction as we can
 799  * @sdp: The GFS2 superblock
 800  *
 801  * Our usual strategy is to defer writing revokes as much as we can in the hope
 802  * that we'll eventually overwrite the journal, which will make those revokes
 803  * go away.  This changes when we flush the log: at that point, there will
 804  * likely be some left-over space in the last revoke block of that transaction.
 805  * We can fill that space with additional revokes for blocks that have already
 806  * been written back.  This will basically come at no cost now, and will save
 807  * us from having to keep track of those blocks on the AIL2 list later.
 808  */
 809 void gfs2_flush_revokes(struct gfs2_sbd *sdp)
 810 {
 811         /* number of revokes we still have room for */
 812         unsigned int max_revokes = atomic_read(&sdp->sd_log_revokes_available);
 813
 814         gfs2_log_lock(sdp);
 815         gfs2_ail1_empty(sdp, max_revokes);
 816         gfs2_log_unlock(sdp);
 817 }
 818
 819 /**
 820  * gfs2_write_log_header - Write a journal log header buffer at lblock
 821  * @sdp: The GFS2 superblock
 822  * @jd: journal descriptor of the journal to which we are writing
 823  * @seq: sequence number
 824  * @tail: tail of the log
 825  * @lblock: value for lh_blkno (block number relative to start of journal)
 826  * @flags: log header flags GFS2_LOG_HEAD_*
 827  * @op_flags: flags to pass to the bio
 828  *
 829  * Returns: the initialized log buffer descriptor
 830  */
 831
 832 void gfs2_write_log_header(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,
 833                            u64 seq, u32 tail, u32 lblock, u32 flags,
 834                            blk_opf_t op_flags)
 835 {
 836         struct gfs2_log_header *lh;
 837         u32 hash, crc;
 838         struct page *page;
 839         struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
 840         struct timespec64 tv;
 841         struct super_block *sb = sdp->sd_vfs;
 842         u64 dblock;
 843
 844         if (gfs2_withdrawn(sdp))
 845                 return;
 846
 847         page = mempool_alloc(gfs2_page_pool, GFP_NOIO);
 848         lh = page_address(page);
 849         clear_page(lh);
 850
 851         lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
 852         lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
 853         lh->lh_header.__pad0 = cpu_to_be64(0);
 854         lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
 855         lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
 856         lh->lh_sequence = cpu_to_be64(seq);
 857         lh->lh_flags = cpu_to_be32(flags);
 858         lh->lh_tail = cpu_to_be32(tail);
 859         lh->lh_blkno = cpu_to_be32(lblock);
 860         hash = ~crc32(~0, lh, LH_V1_SIZE);
 861         lh->lh_hash = cpu_to_be32(hash);
 862
 863         ktime_get_coarse_real_ts64(&tv);
 864         lh->lh_nsec = cpu_to_be32(tv.tv_nsec);
 865         lh->lh_sec = cpu_to_be64(tv.tv_sec);
 866         if (!list_empty(&jd->extent_list))
 867                 dblock = gfs2_log_bmap(jd, lblock);
 868         else {
 869                 unsigned int extlen;
 870                 int ret;
 871
 872                 extlen = 1;
 873                 ret = gfs2_get_extent(jd->jd_inode, lblock, &dblock, &extlen);
 874                 if (gfs2_assert_withdraw(sdp, ret == 0))
 875                         return;
 876         }
 877         lh->lh_addr = cpu_to_be64(dblock);
 878         lh->lh_jinode = cpu_to_be64(GFS2_I(jd->jd_inode)->i_no_addr);
 879
 880         /* We may only write local statfs, quota, etc., when writing to our
 881            own journal. The values are left 0 when recovering a journal
 882            different from our own. */
 883         if (!(flags & GFS2_LOG_HEAD_RECOVERY)) {
 884                 lh->lh_statfs_addr =
 885                         cpu_to_be64(GFS2_I(sdp->sd_sc_inode)->i_no_addr);
 886                 lh->lh_quota_addr =
 887                         cpu_to_be64(GFS2_I(sdp->sd_qc_inode)->i_no_addr);
 888
 889                 spin_lock(&sdp->sd_statfs_spin);
 890                 lh->lh_local_total = cpu_to_be64(l_sc->sc_total);
 891                 lh->lh_local_free = cpu_to_be64(l_sc->sc_free);
 892                 lh->lh_local_dinodes = cpu_to_be64(l_sc->sc_dinodes);
 893                 spin_unlock(&sdp->sd_statfs_spin);
 894         }
 895
 896         BUILD_BUG_ON(offsetof(struct gfs2_log_header, lh_crc) != LH_V1_SIZE);
 897
 898         crc = crc32c(~0, (void *)lh + LH_V1_SIZE + 4,
 899                      sb->s_blocksize - LH_V1_SIZE - 4);
 900         lh->lh_crc = cpu_to_be32(crc);
 901
 902         gfs2_log_write(sdp, jd, page, sb->s_blocksize, 0, dblock);
 903         gfs2_log_submit_bio(&jd->jd_log_bio, REQ_OP_WRITE | op_flags);
 904 }
 905
 906 /**
 907  * log_write_header - Get and initialize a journal header buffer
 908  * @sdp: The GFS2 superblock
 909  * @flags: The log header flags, including log header origin
 910  *
 911  * Returns: the initialized log buffer descriptor
 912  */
 913
 914 static void log_write_header(struct gfs2_sbd *sdp, u32 flags)
 915 {
 916         blk_opf_t op_flags = REQ_PREFLUSH | REQ_FUA | REQ_META | REQ_SYNC;
 917         enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
 918
 919         gfs2_assert_withdraw(sdp, (state != SFS_FROZEN));
 920
 921         if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) {
 922                 gfs2_ordered_wait(sdp);
 923                 log_flush_wait(sdp);
 924                 op_flags = REQ_SYNC | REQ_META | REQ_PRIO;
 925         }
 926         sdp->sd_log_idle = (sdp->sd_log_flush_tail == sdp->sd_log_flush_head);
 927         gfs2_write_log_header(sdp, sdp->sd_jdesc, sdp->sd_log_sequence++,
 928                               sdp->sd_log_flush_tail, sdp->sd_log_flush_head,
 929                               flags, op_flags);
 930         gfs2_log_incr_head(sdp);
 931         log_flush_wait(sdp);
 932         log_pull_tail(sdp);
 933         gfs2_log_update_head(sdp);
 934 }
 935
 936 /**
 937  * gfs2_ail_drain - drain the ail lists after a withdraw
 938  * @sdp: Pointer to GFS2 superblock
 939  */
 940 void gfs2_ail_drain(struct gfs2_sbd *sdp)
 941 {
 942         struct gfs2_trans *tr;
 943
 944         spin_lock(&sdp->sd_ail_lock);
 945         /*
 946          * For transactions on the sd_ail1_list we need to drain both the
 947          * ail1 and ail2 lists. That's because function gfs2_ail1_start_one
 948          * (temporarily) moves items from its tr_ail1 list to tr_ail2 list
 949          * before revokes are sent for that block. Items on the sd_ail2_list
 950          * should have already gotten beyond that point, so no need.
 951          */
 952         while (!list_empty(&sdp->sd_ail1_list)) {
 953                 tr = list_first_entry(&sdp->sd_ail1_list, struct gfs2_trans,
 954                                       tr_list);
 955                 gfs2_ail_empty_tr(sdp, tr, &tr->tr_ail1_list);
 956                 gfs2_ail_empty_tr(sdp, tr, &tr->tr_ail2_list);
 957                 list_del(&tr->tr_list);
 958                 gfs2_trans_free(sdp, tr);
 959         }
 960         while (!list_empty(&sdp->sd_ail2_list)) {
 961                 tr = list_first_entry(&sdp->sd_ail2_list, struct gfs2_trans,
 962                                       tr_list);
 963                 gfs2_ail_empty_tr(sdp, tr, &tr->tr_ail2_list);
 964                 list_del(&tr->tr_list);
 965                 gfs2_trans_free(sdp, tr);
 966         }
 967         gfs2_drain_revokes(sdp);
 968         spin_unlock(&sdp->sd_ail_lock);
 969 }
 970
 971 /**
 972  * empty_ail1_list - try to start IO and empty the ail1 list
 973  * @sdp: Pointer to GFS2 superblock
 974  */
 975 static void empty_ail1_list(struct gfs2_sbd *sdp)
 976 {
 977         unsigned long start = jiffies;
 978
 979         for (;;) {
 980                 if (time_after(jiffies, start + (HZ * 600))) {
 981                         fs_err(sdp, "Error: In %s for 10 minutes! t=%d\n",
 982                                __func__, current->journal_info ? 1 : 0);
 983                         dump_ail_list(sdp);
 984                         return;
 985                 }
 986                 gfs2_ail1_start(sdp);
 987                 gfs2_ail1_wait(sdp);
 988                 if (gfs2_ail1_empty(sdp, 0))
 989                         return;
 990         }
 991 }
 992
 993 /**
 994  * trans_drain - drain the buf and databuf queue for a failed transaction
 995  * @tr: the transaction to drain
 996  *
 997  * When this is called, we're taking an error exit for a log write that failed
 998  * but since we bypassed the after_commit functions, we need to remove the
 999  * items from the buf and databuf queue.
1000  */
1001 static void trans_drain(struct gfs2_trans *tr)
1002 {
1003         struct gfs2_bufdata *bd;
1004         struct list_head *head;
1005
1006         if (!tr)
1007                 return;
1008
1009         head = &tr->tr_buf;
1010         while (!list_empty(head)) {
1011                 bd = list_first_entry(head, struct gfs2_bufdata, bd_list);
1012                 list_del_init(&bd->bd_list);
1013                 if (!list_empty(&bd->bd_ail_st_list))
1014                         gfs2_remove_from_ail(bd);
1015                 kmem_cache_free(gfs2_bufdata_cachep, bd);
1016         }
1017         head = &tr->tr_databuf;
1018         while (!list_empty(head)) {
1019                 bd = list_first_entry(head, struct gfs2_bufdata, bd_list);
1020                 list_del_init(&bd->bd_list);
1021                 if (!list_empty(&bd->bd_ail_st_list))
1022                         gfs2_remove_from_ail(bd);
1023                 kmem_cache_free(gfs2_bufdata_cachep, bd);
1024         }
1025 }
1026
1027 /**
1028  * gfs2_log_flush - flush incore transaction(s)
1029  * @sdp: The filesystem
1030  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
1031  * @flags: The log header flags: GFS2_LOG_HEAD_FLUSH_* and debug flags
1032  *
1033  */
1034
1035 void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
1036 {
1037         struct gfs2_trans *tr = NULL;
1038         unsigned int reserved_blocks = 0, used_blocks = 0;
1039         enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
1040         unsigned int first_log_head;
1041         unsigned int reserved_revokes = 0;
1042
1043         down_write(&sdp->sd_log_flush_lock);
1044         trace_gfs2_log_flush(sdp, 1, flags);
1045
1046 repeat:
1047         /*
1048          * Do this check while holding the log_flush_lock to prevent new
1049          * buffers from being added to the ail via gfs2_pin()
1050          */
1051         if (gfs2_withdrawn(sdp) || !test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
1052                 goto out;
1053
1054         /* Log might have been flushed while we waited for the flush lock */
1055         if (gl && !test_bit(GLF_LFLUSH, &gl->gl_flags))
1056                 goto out;
1057
1058         first_log_head = sdp->sd_log_head;
1059         sdp->sd_log_flush_head = first_log_head;
1060
1061         tr = sdp->sd_log_tr;
1062         if (tr || sdp->sd_log_num_revoke) {
1063                 if (reserved_blocks)
1064                         gfs2_log_release(sdp, reserved_blocks);
1065                 reserved_blocks = sdp->sd_log_blks_reserved;
1066                 reserved_revokes = sdp->sd_log_num_revoke;
1067                 if (tr) {
1068                         sdp->sd_log_tr = NULL;
1069                         tr->tr_first = first_log_head;
1070                         if (unlikely (state == SFS_FROZEN)) {
1071                                 if (gfs2_assert_withdraw_delayed(sdp,
1072                                        !tr->tr_num_buf_new && !tr->tr_num_databuf_new))
1073                                         goto out_withdraw;
1074                         }
1075                 }
1076         } else if (!reserved_blocks) {
1077                 unsigned int taboo_blocks = GFS2_LOG_FLUSH_MIN_BLOCKS;
1078
1079                 reserved_blocks = GFS2_LOG_FLUSH_MIN_BLOCKS;
1080                 if (current == sdp->sd_logd_process)
1081                         taboo_blocks = 0;
1082
1083                 if (!__gfs2_log_try_reserve(sdp, reserved_blocks, taboo_blocks)) {
1084                         up_write(&sdp->sd_log_flush_lock);
1085                         __gfs2_log_reserve(sdp, reserved_blocks, taboo_blocks);
1086                         down_write(&sdp->sd_log_flush_lock);
1087                         goto repeat;
1088                 }
1089                 BUG_ON(sdp->sd_log_num_revoke);
1090         }
1091
1092         if (flags & GFS2_LOG_HEAD_FLUSH_SHUTDOWN)
1093                 clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
1094
1095         if (unlikely(state == SFS_FROZEN))
1096                 if (gfs2_assert_withdraw_delayed(sdp, !reserved_revokes))
1097                         goto out_withdraw;
1098
1099         gfs2_ordered_write(sdp);
1100         if (gfs2_withdrawn(sdp))
1101                 goto out_withdraw;
1102         lops_before_commit(sdp, tr);
1103         if (gfs2_withdrawn(sdp))
1104                 goto out_withdraw;
1105         gfs2_log_submit_bio(&sdp->sd_jdesc->jd_log_bio, REQ_OP_WRITE);
1106         if (gfs2_withdrawn(sdp))
1107                 goto out_withdraw;
1108
1109         if (sdp->sd_log_head != sdp->sd_log_flush_head) {
1110                 log_write_header(sdp, flags);
1111         } else if (sdp->sd_log_tail != sdp->sd_log_flush_tail && !sdp->sd_log_idle) {
1112                 log_write_header(sdp, flags);
1113         }
1114         if (gfs2_withdrawn(sdp))
1115                 goto out_withdraw;
1116         lops_after_commit(sdp, tr);
1117
1118         gfs2_log_lock(sdp);
1119         sdp->sd_log_blks_reserved = 0;
1120
1121         spin_lock(&sdp->sd_ail_lock);
1122         if (tr && !list_empty(&tr->tr_ail1_list)) {
1123                 list_add(&tr->tr_list, &sdp->sd_ail1_list);
1124                 tr = NULL;
1125         }
1126         spin_unlock(&sdp->sd_ail_lock);
1127         gfs2_log_unlock(sdp);
1128
1129         if (!(flags & GFS2_LOG_HEAD_FLUSH_NORMAL)) {
1130                 if (!sdp->sd_log_idle) {
1131                         empty_ail1_list(sdp);
1132                         if (gfs2_withdrawn(sdp))
1133                                 goto out_withdraw;
1134                         log_write_header(sdp, flags);
1135                 }
1136                 if (flags & (GFS2_LOG_HEAD_FLUSH_SHUTDOWN |
1137                              GFS2_LOG_HEAD_FLUSH_FREEZE))
1138                         gfs2_log_shutdown(sdp);
1139                 if (flags & GFS2_LOG_HEAD_FLUSH_FREEZE)
1140                         atomic_set(&sdp->sd_freeze_state, SFS_FROZEN);
1141         }
1142
1143 out_end:
1144         used_blocks = log_distance(sdp, sdp->sd_log_flush_head, first_log_head);
1145         reserved_revokes += atomic_read(&sdp->sd_log_revokes_available);
1146         atomic_set(&sdp->sd_log_revokes_available, sdp->sd_ldptrs);
1147         gfs2_assert_withdraw(sdp, reserved_revokes % sdp->sd_inptrs == sdp->sd_ldptrs);
1148         if (reserved_revokes > sdp->sd_ldptrs)
1149                 reserved_blocks += (reserved_revokes - sdp->sd_ldptrs) / sdp->sd_inptrs;
1150 out:
1151         if (used_blocks != reserved_blocks) {
1152                 gfs2_assert_withdraw_delayed(sdp, used_blocks < reserved_blocks);
1153                 gfs2_log_release(sdp, reserved_blocks - used_blocks);
1154         }
1155         up_write(&sdp->sd_log_flush_lock);
1156         gfs2_trans_free(sdp, tr);
1157         if (gfs2_withdrawing(sdp))
1158                 gfs2_withdraw(sdp);
1159         trace_gfs2_log_flush(sdp, 0, flags);
1160         return;
1161
1162 out_withdraw:
1163         trans_drain(tr);
1164         /**
1165          * If the tr_list is empty, we're withdrawing during a log
1166          * flush that targets a transaction, but the transaction was
1167          * never queued onto any of the ail lists. Here we add it to
1168          * ail1 just so that ail_drain() will find and free it.
1169          */
1170         spin_lock(&sdp->sd_ail_lock);
1171         if (tr && list_empty(&tr->tr_list))
1172                 list_add(&tr->tr_list, &sdp->sd_ail1_list);
1173         spin_unlock(&sdp->sd_ail_lock);
1174         tr = NULL;
1175         goto out_end;
1176 }
1177
1178 /**
1179  * gfs2_merge_trans - Merge a new transaction into a cached transaction
1180  * @sdp: the filesystem
1181  * @new: New transaction to be merged
1182  */
1183
1184 static void gfs2_merge_trans(struct gfs2_sbd *sdp, struct gfs2_trans *new)
1185 {
1186         struct gfs2_trans *old = sdp->sd_log_tr;
1187
1188         WARN_ON_ONCE(!test_bit(TR_ATTACHED, &old->tr_flags));
1189
1190         old->tr_num_buf_new     += new->tr_num_buf_new;
1191         old->tr_num_databuf_new += new->tr_num_databuf_new;
1192         old->tr_num_buf_rm      += new->tr_num_buf_rm;
1193         old->tr_num_databuf_rm  += new->tr_num_databuf_rm;
1194         old->tr_revokes         += new->tr_revokes;
1195         old->tr_num_revoke      += new->tr_num_revoke;
1196
1197         list_splice_tail_init(&new->tr_databuf, &old->tr_databuf);
1198         list_splice_tail_init(&new->tr_buf, &old->tr_buf);
1199
1200         spin_lock(&sdp->sd_ail_lock);
1201         list_splice_tail_init(&new->tr_ail1_list, &old->tr_ail1_list);
1202         list_splice_tail_init(&new->tr_ail2_list, &old->tr_ail2_list);
1203         spin_unlock(&sdp->sd_ail_lock);
1204 }
1205
1206 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
1207 {
1208         unsigned int reserved;
1209         unsigned int unused;
1210         unsigned int maxres;
1211
1212         gfs2_log_lock(sdp);
1213
1214         if (sdp->sd_log_tr) {
1215                 gfs2_merge_trans(sdp, tr);
1216         } else if (tr->tr_num_buf_new || tr->tr_num_databuf_new) {
1217                 gfs2_assert_withdraw(sdp, !test_bit(TR_ONSTACK, &tr->tr_flags));
1218                 sdp->sd_log_tr = tr;
1219                 set_bit(TR_ATTACHED, &tr->tr_flags);
1220         }
1221
1222         reserved = calc_reserved(sdp);
1223         maxres = sdp->sd_log_blks_reserved + tr->tr_reserved;
1224         gfs2_assert_withdraw(sdp, maxres >= reserved);
1225         unused = maxres - reserved;
1226         if (unused)
1227                 gfs2_log_release(sdp, unused);
1228         sdp->sd_log_blks_reserved = reserved;
1229
1230         gfs2_log_unlock(sdp);
1231 }
1232
1233 /**
1234  * gfs2_log_commit - Commit a transaction to the log
1235  * @sdp: the filesystem
1236  * @tr: the transaction
1237  *
1238  * We wake up gfs2_logd if the number of pinned blocks exceed thresh1
1239  * or the total number of used blocks (pinned blocks plus AIL blocks)
1240  * is greater than thresh2.
1241  *
1242  * At mount time thresh1 is 2/5ths of journal size, thresh2 is 4/5ths of
1243  * journal size.
1244  *
1245  * Returns: errno
1246  */
1247
1248 void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
1249 {
1250         log_refund(sdp, tr);
1251
1252         if (atomic_read(&sdp->sd_log_pinned) > atomic_read(&sdp->sd_log_thresh1) ||
1253             ((sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free)) >
1254             atomic_read(&sdp->sd_log_thresh2)))
1255                 wake_up(&sdp->sd_logd_waitq);
1256 }
1257
1258 /**
1259  * gfs2_log_shutdown - write a shutdown header into a journal
1260  * @sdp: the filesystem
1261  *
1262  */
1263
1264 static void gfs2_log_shutdown(struct gfs2_sbd *sdp)
1265 {
1266         gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
1267         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
1268         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
1269
1270         log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT | GFS2_LFC_SHUTDOWN);
1271         log_pull_tail(sdp);
1272
1273         gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
1274         gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
1275 }
1276
1277 static inline int gfs2_jrnl_flush_reqd(struct gfs2_sbd *sdp)
1278 {
1279         return (atomic_read(&sdp->sd_log_pinned) +
1280                 atomic_read(&sdp->sd_log_blks_needed) >=
1281                 atomic_read(&sdp->sd_log_thresh1));
1282 }
1283
1284 static inline int gfs2_ail_flush_reqd(struct gfs2_sbd *sdp)
1285 {
1286         unsigned int used_blocks = sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free);
1287
1288         return used_blocks + atomic_read(&sdp->sd_log_blks_needed) >=
1289                 atomic_read(&sdp->sd_log_thresh2);
1290 }
1291
1292 /**
1293  * gfs2_logd - Update log tail as Active Items get flushed to in-place blocks
1294  * @data: Pointer to GFS2 superblock
1295  *
1296  * Also, periodically check to make sure that we're using the most recent
1297  * journal index.
1298  */
1299
1300 int gfs2_logd(void *data)
1301 {
1302         struct gfs2_sbd *sdp = data;
1303         unsigned long t = 1;
1304
1305         while (!kthread_should_stop()) {
1306
1307                 if (gfs2_withdrawn(sdp)) {
1308                         msleep_interruptible(HZ);
1309                         continue;
1310                 }
1311                 /* Check for errors writing to the journal */
1312                 if (sdp->sd_log_error) {
1313                         gfs2_lm(sdp,
1314                                 "GFS2: fsid=%s: error %d: "
1315                                 "withdrawing the file system to "
1316                                 "prevent further damage.\n",
1317                                 sdp->sd_fsname, sdp->sd_log_error);
1318                         gfs2_withdraw(sdp);
1319                         continue;
1320                 }
1321
1322                 if (gfs2_jrnl_flush_reqd(sdp) || t == 0) {
1323                         gfs2_ail1_empty(sdp, 0);
1324                         gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
1325                                                   GFS2_LFC_LOGD_JFLUSH_REQD);
1326                 }
1327
1328                 if (test_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags) ||
1329                     gfs2_ail_flush_reqd(sdp)) {
1330                         clear_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags);
1331                         gfs2_ail1_start(sdp);
1332                         gfs2_ail1_wait(sdp);
1333                         gfs2_ail1_empty(sdp, 0);
1334                         gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
1335                                                   GFS2_LFC_LOGD_AIL_FLUSH_REQD);
1336                 }
1337
1338                 t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
1339
1340                 try_to_freeze();
1341
1342                 t = wait_event_interruptible_timeout(sdp->sd_logd_waitq,
1343                                 test_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags) ||
1344                                 gfs2_ail_flush_reqd(sdp) ||
1345                                 gfs2_jrnl_flush_reqd(sdp) ||
1346                                 kthread_should_stop(),
1347                                 t);
1348         }
1349
1350         return 0;
1351 }
1352