fs/jbd2/commit.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * linux/fs/jbd2/commit.c
   4  *
   5  * Written by Stephen C. Tweedie <[email protected]>, 1998
   6  *
   7  * Copyright 1998 Red Hat corp --- All Rights Reserved
   8  *
   9  * Journal commit routines for the generic filesystem journaling code;
  10  * part of the ext2fs journaling system.
  11  */
  12
  13 #include <linux/time.h>
  14 #include <linux/fs.h>
  15 #include <linux/jbd2.h>
  16 #include <linux/errno.h>
  17 #include <linux/slab.h>
  18 #include <linux/mm.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/jiffies.h>
  21 #include <linux/crc32.h>
  22 #include <linux/writeback.h>
  23 #include <linux/backing-dev.h>
  24 #include <linux/bio.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/bitops.h>
  27 #include <trace/events/jbd2.h>
  28
  29 /*
  30  * IO end handler for temporary buffer_heads handling writes to the journal.
  31  */
  32 static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
  33 {
  34         struct buffer_head *orig_bh = bh->b_private;
  35
  36         BUFFER_TRACE(bh, "");
  37         if (uptodate)
  38                 set_buffer_uptodate(bh);
  39         else
  40                 clear_buffer_uptodate(bh);
  41         if (orig_bh) {
  42                 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
  43                 smp_mb__after_atomic();
  44                 wake_up_bit(&orig_bh->b_state, BH_Shadow);
  45         }
  46         unlock_buffer(bh);
  47 }
  48
  49 /*
  50  * When an ext4 file is truncated, it is possible that some pages are not
  51  * successfully freed, because they are attached to a committing transaction.
  52  * After the transaction commits, these pages are left on the LRU, with no
  53  * ->mapping, and with attached buffers.  These pages are trivially reclaimable
  54  * by the VM, but their apparent absence upsets the VM accounting, and it makes
  55  * the numbers in /proc/meminfo look odd.
  56  *
  57  * So here, we have a buffer which has just come off the forget list.  Look to
  58  * see if we can strip all buffers from the backing page.
  59  *
  60  * Called under lock_journal(), and possibly under journal_datalist_lock.  The
  61  * caller provided us with a ref against the buffer, and we drop that here.
  62  */
  63 static void release_buffer_page(struct buffer_head *bh)
  64 {
  65         struct folio *folio;
  66         struct page *page;
  67
  68         if (buffer_dirty(bh))
  69                 goto nope;
  70         if (atomic_read(&bh->b_count) != 1)
  71                 goto nope;
  72         page = bh->b_page;
  73         if (!page)
  74                 goto nope;
  75         folio = page_folio(page);
  76         if (folio->mapping)
  77                 goto nope;
  78
  79         /* OK, it's a truncated page */
  80         if (!folio_trylock(folio))
  81                 goto nope;
  82
  83         folio_get(folio);
  84         __brelse(bh);
  85         try_to_free_buffers(folio);
  86         folio_unlock(folio);
  87         folio_put(folio);
  88         return;
  89
  90 nope:
  91         __brelse(bh);
  92 }
  93
  94 static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
  95 {
  96         struct commit_header *h;
  97         __u32 csum;
  98
  99         if (!jbd2_journal_has_csum_v2or3(j))
 100                 return;
 101
 102         h = (struct commit_header *)(bh->b_data);
 103         h->h_chksum_type = 0;
 104         h->h_chksum_size = 0;
 105         h->h_chksum[0] = 0;
 106         csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
 107         h->h_chksum[0] = cpu_to_be32(csum);
 108 }
 109
 110 /*
 111  * Done it all: now submit the commit record.  We should have
 112  * cleaned up our previous buffers by now, so if we are in abort
 113  * mode we can now just skip the rest of the journal write
 114  * entirely.
 115  *
 116  * Returns 1 if the journal needs to be aborted or 0 on success
 117  */
 118 static int journal_submit_commit_record(journal_t *journal,
 119                                         transaction_t *commit_transaction,
 120                                         struct buffer_head **cbh,
 121                                         __u32 crc32_sum)
 122 {
 123         struct commit_header *tmp;
 124         struct buffer_head *bh;
 125         struct timespec64 now;
 126         blk_opf_t write_flags = REQ_OP_WRITE | REQ_SYNC;
 127
 128         *cbh = NULL;
 129
 130         if (is_journal_aborted(journal))
 131                 return 0;
 132
 133         bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
 134                                                 JBD2_COMMIT_BLOCK);
 135         if (!bh)
 136                 return 1;
 137
 138         tmp = (struct commit_header *)bh->b_data;
 139         ktime_get_coarse_real_ts64(&now);
 140         tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
 141         tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
 142
 143         if (jbd2_has_feature_checksum(journal)) {
 144                 tmp->h_chksum_type      = JBD2_CRC32_CHKSUM;
 145                 tmp->h_chksum_size      = JBD2_CRC32_CHKSUM_SIZE;
 146                 tmp->h_chksum[0]        = cpu_to_be32(crc32_sum);
 147         }
 148         jbd2_commit_block_csum_set(journal, bh);
 149
 150         BUFFER_TRACE(bh, "submit commit block");
 151         lock_buffer(bh);
 152         clear_buffer_dirty(bh);
 153         set_buffer_uptodate(bh);
 154         bh->b_end_io = journal_end_buffer_io_sync;
 155
 156         if (journal->j_flags & JBD2_BARRIER &&
 157             !jbd2_has_feature_async_commit(journal))
 158                 write_flags |= REQ_PREFLUSH | REQ_FUA;
 159
 160         submit_bh(write_flags, bh);
 161         *cbh = bh;
 162         return 0;
 163 }
 164
 165 /*
 166  * This function along with journal_submit_commit_record
 167  * allows to write the commit record asynchronously.
 168  */
 169 static int journal_wait_on_commit_record(journal_t *journal,
 170                                          struct buffer_head *bh)
 171 {
 172         int ret = 0;
 173
 174         clear_buffer_dirty(bh);
 175         wait_on_buffer(bh);
 176
 177         if (unlikely(!buffer_uptodate(bh)))
 178                 ret = -EIO;
 179         put_bh(bh);            /* One for getblk() */
 180
 181         return ret;
 182 }
 183
 184 /*
 185  * write the filemap data using writepage() address_space_operations.
 186  * We don't do block allocation here even for delalloc. We don't
 187  * use writepages() because with delayed allocation we may be doing
 188  * block allocation in writepages().
 189  */
 190 int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
 191 {
 192         struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
 193         struct writeback_control wbc = {
 194                 .sync_mode =  WB_SYNC_ALL,
 195                 .nr_to_write = mapping->nrpages * 2,
 196                 .range_start = jinode->i_dirty_start,
 197                 .range_end = jinode->i_dirty_end,
 198         };
 199
 200         /*
 201          * submit the inode data buffers. We use writepage
 202          * instead of writepages. Because writepages can do
 203          * block allocation with delalloc. We need to write
 204          * only allocated blocks here.
 205          */
 206         return generic_writepages(mapping, &wbc);
 207 }
 208
 209 /* Send all the data buffers related to an inode */
 210 int jbd2_submit_inode_data(struct jbd2_inode *jinode)
 211 {
 212
 213         if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
 214                 return 0;
 215
 216         trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
 217         return jbd2_journal_submit_inode_data_buffers(jinode);
 218
 219 }
 220 EXPORT_SYMBOL(jbd2_submit_inode_data);
 221
 222 int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
 223 {
 224         if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
 225                 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
 226                 return 0;
 227         return filemap_fdatawait_range_keep_errors(
 228                 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
 229                 jinode->i_dirty_end);
 230 }
 231 EXPORT_SYMBOL(jbd2_wait_inode_data);
 232
 233 /*
 234  * Submit all the data buffers of inode associated with the transaction to
 235  * disk.
 236  *
 237  * We are in a committing transaction. Therefore no new inode can be added to
 238  * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
 239  * operate on from being released while we write out pages.
 240  */
 241 static int journal_submit_data_buffers(journal_t *journal,
 242                 transaction_t *commit_transaction)
 243 {
 244         struct jbd2_inode *jinode;
 245         int err, ret = 0;
 246
 247         spin_lock(&journal->j_list_lock);
 248         list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
 249                 if (!(jinode->i_flags & JI_WRITE_DATA))
 250                         continue;
 251                 jinode->i_flags |= JI_COMMIT_RUNNING;
 252                 spin_unlock(&journal->j_list_lock);
 253                 /* submit the inode data buffers. */
 254                 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
 255                 if (journal->j_submit_inode_data_buffers) {
 256                         err = journal->j_submit_inode_data_buffers(jinode);
 257                         if (!ret)
 258                                 ret = err;
 259                 }
 260                 spin_lock(&journal->j_list_lock);
 261                 J_ASSERT(jinode->i_transaction == commit_transaction);
 262                 jinode->i_flags &= ~JI_COMMIT_RUNNING;
 263                 smp_mb();
 264                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
 265         }
 266         spin_unlock(&journal->j_list_lock);
 267         return ret;
 268 }
 269
 270 int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
 271 {
 272         struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
 273
 274         return filemap_fdatawait_range_keep_errors(mapping,
 275                                                    jinode->i_dirty_start,
 276                                                    jinode->i_dirty_end);
 277 }
 278
 279 /*
 280  * Wait for data submitted for writeout, refile inodes to proper
 281  * transaction if needed.
 282  *
 283  */
 284 static int journal_finish_inode_data_buffers(journal_t *journal,
 285                 transaction_t *commit_transaction)
 286 {
 287         struct jbd2_inode *jinode, *next_i;
 288         int err, ret = 0;
 289
 290         /* For locking, see the comment in journal_submit_data_buffers() */
 291         spin_lock(&journal->j_list_lock);
 292         list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
 293                 if (!(jinode->i_flags & JI_WAIT_DATA))
 294                         continue;
 295                 jinode->i_flags |= JI_COMMIT_RUNNING;
 296                 spin_unlock(&journal->j_list_lock);
 297                 /* wait for the inode data buffers writeout. */
 298                 if (journal->j_finish_inode_data_buffers) {
 299                         err = journal->j_finish_inode_data_buffers(jinode);
 300                         if (!ret)
 301                                 ret = err;
 302                 }
 303                 spin_lock(&journal->j_list_lock);
 304                 jinode->i_flags &= ~JI_COMMIT_RUNNING;
 305                 smp_mb();
 306                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
 307         }
 308
 309         /* Now refile inode to proper lists */
 310         list_for_each_entry_safe(jinode, next_i,
 311                                  &commit_transaction->t_inode_list, i_list) {
 312                 list_del(&jinode->i_list);
 313                 if (jinode->i_next_transaction) {
 314                         jinode->i_transaction = jinode->i_next_transaction;
 315                         jinode->i_next_transaction = NULL;
 316                         list_add(&jinode->i_list,
 317                                 &jinode->i_transaction->t_inode_list);
 318                 } else {
 319                         jinode->i_transaction = NULL;
 320                         jinode->i_dirty_start = 0;
 321                         jinode->i_dirty_end = 0;
 322                 }
 323         }
 324         spin_unlock(&journal->j_list_lock);
 325
 326         return ret;
 327 }
 328
 329 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
 330 {
 331         struct page *page = bh->b_page;
 332         char *addr;
 333         __u32 checksum;
 334
 335         addr = kmap_atomic(page);
 336         checksum = crc32_be(crc32_sum,
 337                 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
 338         kunmap_atomic(addr);
 339
 340         return checksum;
 341 }
 342
 343 static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
 344                                    unsigned long long block)
 345 {
 346         tag->t_blocknr = cpu_to_be32(block & (u32)~0);
 347         if (jbd2_has_feature_64bit(j))
 348                 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
 349 }
 350
 351 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
 352                                     struct buffer_head *bh, __u32 sequence)
 353 {
 354         journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
 355         struct page *page = bh->b_page;
 356         __u8 *addr;
 357         __u32 csum32;
 358         __be32 seq;
 359
 360         if (!jbd2_journal_has_csum_v2or3(j))
 361                 return;
 362
 363         seq = cpu_to_be32(sequence);
 364         addr = kmap_atomic(page);
 365         csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
 366         csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
 367                              bh->b_size);
 368         kunmap_atomic(addr);
 369
 370         if (jbd2_has_feature_csum3(j))
 371                 tag3->t_checksum = cpu_to_be32(csum32);
 372         else
 373                 tag->t_checksum = cpu_to_be16(csum32);
 374 }
 375 /*
 376  * jbd2_journal_commit_transaction
 377  *
 378  * The primary function for committing a transaction to the log.  This
 379  * function is called by the journal thread to begin a complete commit.
 380  */
 381 void jbd2_journal_commit_transaction(journal_t *journal)
 382 {
 383         struct transaction_stats_s stats;
 384         transaction_t *commit_transaction;
 385         struct journal_head *jh;
 386         struct buffer_head *descriptor;
 387         struct buffer_head **wbuf = journal->j_wbuf;
 388         int bufs;
 389         int flags;
 390         int err;
 391         unsigned long long blocknr;
 392         ktime_t start_time;
 393         u64 commit_time;
 394         char *tagp = NULL;
 395         journal_block_tag_t *tag = NULL;
 396         int space_left = 0;
 397         int first_tag = 0;
 398         int tag_flag;
 399         int i;
 400         int tag_bytes = journal_tag_bytes(journal);
 401         struct buffer_head *cbh = NULL; /* For transactional checksums */
 402         __u32 crc32_sum = ~0;
 403         struct blk_plug plug;
 404         /* Tail of the journal */
 405         unsigned long first_block;
 406         tid_t first_tid;
 407         int update_tail;
 408         int csum_size = 0;
 409         LIST_HEAD(io_bufs);
 410         LIST_HEAD(log_bufs);
 411
 412         if (jbd2_journal_has_csum_v2or3(journal))
 413                 csum_size = sizeof(struct jbd2_journal_block_tail);
 414
 415         /*
 416          * First job: lock down the current transaction and wait for
 417          * all outstanding updates to complete.
 418          */
 419
 420         /* Do we need to erase the effects of a prior jbd2_journal_flush? */
 421         if (journal->j_flags & JBD2_FLUSHED) {
 422                 jbd2_debug(3, "super block updated\n");
 423                 mutex_lock_io(&journal->j_checkpoint_mutex);
 424                 /*
 425                  * We hold j_checkpoint_mutex so tail cannot change under us.
 426                  * We don't need any special data guarantees for writing sb
 427                  * since journal is empty and it is ok for write to be
 428                  * flushed only with transaction commit.
 429                  */
 430                 jbd2_journal_update_sb_log_tail(journal,
 431                                                 journal->j_tail_sequence,
 432                                                 journal->j_tail,
 433                                                 REQ_SYNC);
 434                 mutex_unlock(&journal->j_checkpoint_mutex);
 435         } else {
 436                 jbd2_debug(3, "superblock not updated\n");
 437         }
 438
 439         J_ASSERT(journal->j_running_transaction != NULL);
 440         J_ASSERT(journal->j_committing_transaction == NULL);
 441
 442         write_lock(&journal->j_state_lock);
 443         journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
 444         while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
 445                 DEFINE_WAIT(wait);
 446
 447                 prepare_to_wait(&journal->j_fc_wait, &wait,
 448                                 TASK_UNINTERRUPTIBLE);
 449                 write_unlock(&journal->j_state_lock);
 450                 schedule();
 451                 write_lock(&journal->j_state_lock);
 452                 finish_wait(&journal->j_fc_wait, &wait);
 453                 /*
 454                  * TODO: by blocking fast commits here, we are increasing
 455                  * fsync() latency slightly. Strictly speaking, we don't need
 456                  * to block fast commits until the transaction enters T_FLUSH
 457                  * state. So an optimization is possible where we block new fast
 458                  * commits here and wait for existing ones to complete
 459                  * just before we enter T_FLUSH. That way, the existing fast
 460                  * commits and this full commit can proceed parallely.
 461                  */
 462         }
 463         write_unlock(&journal->j_state_lock);
 464
 465         commit_transaction = journal->j_running_transaction;
 466
 467         trace_jbd2_start_commit(journal, commit_transaction);
 468         jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
 469                         commit_transaction->t_tid);
 470
 471         write_lock(&journal->j_state_lock);
 472         journal->j_fc_off = 0;
 473         J_ASSERT(commit_transaction->t_state == T_RUNNING);
 474         commit_transaction->t_state = T_LOCKED;
 475
 476         trace_jbd2_commit_locking(journal, commit_transaction);
 477         stats.run.rs_wait = commit_transaction->t_max_wait;
 478         stats.run.rs_request_delay = 0;
 479         stats.run.rs_locked = jiffies;
 480         if (commit_transaction->t_requested)
 481                 stats.run.rs_request_delay =
 482                         jbd2_time_diff(commit_transaction->t_requested,
 483                                        stats.run.rs_locked);
 484         stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
 485                                               stats.run.rs_locked);
 486
 487         // waits for any t_updates to finish
 488         jbd2_journal_wait_updates(journal);
 489
 490         commit_transaction->t_state = T_SWITCH;
 491
 492         J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
 493                         journal->j_max_transaction_buffers);
 494
 495         /*
 496          * First thing we are allowed to do is to discard any remaining
 497          * BJ_Reserved buffers.  Note, it is _not_ permissible to assume
 498          * that there are no such buffers: if a large filesystem
 499          * operation like a truncate needs to split itself over multiple
 500          * transactions, then it may try to do a jbd2_journal_restart() while
 501          * there are still BJ_Reserved buffers outstanding.  These must
 502          * be released cleanly from the current transaction.
 503          *
 504          * In this case, the filesystem must still reserve write access
 505          * again before modifying the buffer in the new transaction, but
 506          * we do not require it to remember exactly which old buffers it
 507          * has reserved.  This is consistent with the existing behaviour
 508          * that multiple jbd2_journal_get_write_access() calls to the same
 509          * buffer are perfectly permissible.
 510          * We use journal->j_state_lock here to serialize processing of
 511          * t_reserved_list with eviction of buffers from journal_unmap_buffer().
 512          */
 513         while (commit_transaction->t_reserved_list) {
 514                 jh = commit_transaction->t_reserved_list;
 515                 JBUFFER_TRACE(jh, "reserved, unused: refile");
 516                 /*
 517                  * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
 518                  * leave undo-committed data.
 519                  */
 520                 if (jh->b_committed_data) {
 521                         struct buffer_head *bh = jh2bh(jh);
 522
 523                         spin_lock(&jh->b_state_lock);
 524                         jbd2_free(jh->b_committed_data, bh->b_size);
 525                         jh->b_committed_data = NULL;
 526                         spin_unlock(&jh->b_state_lock);
 527                 }
 528                 jbd2_journal_refile_buffer(journal, jh);
 529         }
 530
 531         write_unlock(&journal->j_state_lock);
 532         /*
 533          * Now try to drop any written-back buffers from the journal's
 534          * checkpoint lists.  We do this *before* commit because it potentially
 535          * frees some memory
 536          */
 537         spin_lock(&journal->j_list_lock);
 538         __jbd2_journal_clean_checkpoint_list(journal, false);
 539         spin_unlock(&journal->j_list_lock);
 540
 541         jbd2_debug(3, "JBD2: commit phase 1\n");
 542
 543         /*
 544          * Clear revoked flag to reflect there is no revoked buffers
 545          * in the next transaction which is going to be started.
 546          */
 547         jbd2_clear_buffer_revoked_flags(journal);
 548
 549         /*
 550          * Switch to a new revoke table.
 551          */
 552         jbd2_journal_switch_revoke_table(journal);
 553
 554         write_lock(&journal->j_state_lock);
 555         /*
 556          * Reserved credits cannot be claimed anymore, free them
 557          */
 558         atomic_sub(atomic_read(&journal->j_reserved_credits),
 559                    &commit_transaction->t_outstanding_credits);
 560
 561         trace_jbd2_commit_flushing(journal, commit_transaction);
 562         stats.run.rs_flushing = jiffies;
 563         stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
 564                                              stats.run.rs_flushing);
 565
 566         commit_transaction->t_state = T_FLUSH;
 567         journal->j_committing_transaction = commit_transaction;
 568         journal->j_running_transaction = NULL;
 569         start_time = ktime_get();
 570         commit_transaction->t_log_start = journal->j_head;
 571         wake_up_all(&journal->j_wait_transaction_locked);
 572         write_unlock(&journal->j_state_lock);
 573
 574         jbd2_debug(3, "JBD2: commit phase 2a\n");
 575
 576         /*
 577          * Now start flushing things to disk, in the order they appear
 578          * on the transaction lists.  Data blocks go first.
 579          */
 580         err = journal_submit_data_buffers(journal, commit_transaction);
 581         if (err)
 582                 jbd2_journal_abort(journal, err);
 583
 584         blk_start_plug(&plug);
 585         jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
 586
 587         jbd2_debug(3, "JBD2: commit phase 2b\n");
 588
 589         /*
 590          * Way to go: we have now written out all of the data for a
 591          * transaction!  Now comes the tricky part: we need to write out
 592          * metadata.  Loop over the transaction's entire buffer list:
 593          */
 594         write_lock(&journal->j_state_lock);
 595         commit_transaction->t_state = T_COMMIT;
 596         write_unlock(&journal->j_state_lock);
 597
 598         trace_jbd2_commit_logging(journal, commit_transaction);
 599         stats.run.rs_logging = jiffies;
 600         stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
 601                                                stats.run.rs_logging);
 602         stats.run.rs_blocks = commit_transaction->t_nr_buffers;
 603         stats.run.rs_blocks_logged = 0;
 604
 605         J_ASSERT(commit_transaction->t_nr_buffers <=
 606                  atomic_read(&commit_transaction->t_outstanding_credits));
 607
 608         err = 0;
 609         bufs = 0;
 610         descriptor = NULL;
 611         while (commit_transaction->t_buffers) {
 612
 613                 /* Find the next buffer to be journaled... */
 614
 615                 jh = commit_transaction->t_buffers;
 616
 617                 /* If we're in abort mode, we just un-journal the buffer and
 618                    release it. */
 619
 620                 if (is_journal_aborted(journal)) {
 621                         clear_buffer_jbddirty(jh2bh(jh));
 622                         JBUFFER_TRACE(jh, "journal is aborting: refile");
 623                         jbd2_buffer_abort_trigger(jh,
 624                                                   jh->b_frozen_data ?
 625                                                   jh->b_frozen_triggers :
 626                                                   jh->b_triggers);
 627                         jbd2_journal_refile_buffer(journal, jh);
 628                         /* If that was the last one, we need to clean up
 629                          * any descriptor buffers which may have been
 630                          * already allocated, even if we are now
 631                          * aborting. */
 632                         if (!commit_transaction->t_buffers)
 633                                 goto start_journal_io;
 634                         continue;
 635                 }
 636
 637                 /* Make sure we have a descriptor block in which to
 638                    record the metadata buffer. */
 639
 640                 if (!descriptor) {
 641                         J_ASSERT (bufs == 0);
 642
 643                         jbd2_debug(4, "JBD2: get descriptor\n");
 644
 645                         descriptor = jbd2_journal_get_descriptor_buffer(
 646                                                         commit_transaction,
 647                                                         JBD2_DESCRIPTOR_BLOCK);
 648                         if (!descriptor) {
 649                                 jbd2_journal_abort(journal, -EIO);
 650                                 continue;
 651                         }
 652
 653                         jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
 654                                 (unsigned long long)descriptor->b_blocknr,
 655                                 descriptor->b_data);
 656                         tagp = &descriptor->b_data[sizeof(journal_header_t)];
 657                         space_left = descriptor->b_size -
 658                                                 sizeof(journal_header_t);
 659                         first_tag = 1;
 660                         set_buffer_jwrite(descriptor);
 661                         set_buffer_dirty(descriptor);
 662                         wbuf[bufs++] = descriptor;
 663
 664                         /* Record it so that we can wait for IO
 665                            completion later */
 666                         BUFFER_TRACE(descriptor, "ph3: file as descriptor");
 667                         jbd2_file_log_bh(&log_bufs, descriptor);
 668                 }
 669
 670                 /* Where is the buffer to be written? */
 671
 672                 err = jbd2_journal_next_log_block(journal, &blocknr);
 673                 /* If the block mapping failed, just abandon the buffer
 674                    and repeat this loop: we'll fall into the
 675                    refile-on-abort condition above. */
 676                 if (err) {
 677                         jbd2_journal_abort(journal, err);
 678                         continue;
 679                 }
 680
 681                 /*
 682                  * start_this_handle() uses t_outstanding_credits to determine
 683                  * the free space in the log.
 684                  */
 685                 atomic_dec(&commit_transaction->t_outstanding_credits);
 686
 687                 /* Bump b_count to prevent truncate from stumbling over
 688                    the shadowed buffer!  @@@ This can go if we ever get
 689                    rid of the shadow pairing of buffers. */
 690                 atomic_inc(&jh2bh(jh)->b_count);
 691
 692                 /*
 693                  * Make a temporary IO buffer with which to write it out
 694                  * (this will requeue the metadata buffer to BJ_Shadow).
 695                  */
 696                 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
 697                 JBUFFER_TRACE(jh, "ph3: write metadata");
 698                 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
 699                                                 jh, &wbuf[bufs], blocknr);
 700                 if (flags < 0) {
 701                         jbd2_journal_abort(journal, flags);
 702                         continue;
 703                 }
 704                 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
 705
 706                 /* Record the new block's tag in the current descriptor
 707                    buffer */
 708
 709                 tag_flag = 0;
 710                 if (flags & 1)
 711                         tag_flag |= JBD2_FLAG_ESCAPE;
 712                 if (!first_tag)
 713                         tag_flag |= JBD2_FLAG_SAME_UUID;
 714
 715                 tag = (journal_block_tag_t *) tagp;
 716                 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
 717                 tag->t_flags = cpu_to_be16(tag_flag);
 718                 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
 719                                         commit_transaction->t_tid);
 720                 tagp += tag_bytes;
 721                 space_left -= tag_bytes;
 722                 bufs++;
 723
 724                 if (first_tag) {
 725                         memcpy (tagp, journal->j_uuid, 16);
 726                         tagp += 16;
 727                         space_left -= 16;
 728                         first_tag = 0;
 729                 }
 730
 731                 /* If there's no more to do, or if the descriptor is full,
 732                    let the IO rip! */
 733
 734                 if (bufs == journal->j_wbufsize ||
 735                     commit_transaction->t_buffers == NULL ||
 736                     space_left < tag_bytes + 16 + csum_size) {
 737
 738                         jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
 739
 740                         /* Write an end-of-descriptor marker before
 741                            submitting the IOs.  "tag" still points to
 742                            the last tag we set up. */
 743
 744                         tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
 745 start_journal_io:
 746                         if (descriptor)
 747                                 jbd2_descriptor_block_csum_set(journal,
 748                                                         descriptor);
 749
 750                         for (i = 0; i < bufs; i++) {
 751                                 struct buffer_head *bh = wbuf[i];
 752                                 /*
 753                                  * Compute checksum.
 754                                  */
 755                                 if (jbd2_has_feature_checksum(journal)) {
 756                                         crc32_sum =
 757                                             jbd2_checksum_data(crc32_sum, bh);
 758                                 }
 759
 760                                 lock_buffer(bh);
 761                                 clear_buffer_dirty(bh);
 762                                 set_buffer_uptodate(bh);
 763                                 bh->b_end_io = journal_end_buffer_io_sync;
 764                                 submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
 765                         }
 766                         cond_resched();
 767
 768                         /* Force a new descriptor to be generated next
 769                            time round the loop. */
 770                         descriptor = NULL;
 771                         bufs = 0;
 772                 }
 773         }
 774
 775         err = journal_finish_inode_data_buffers(journal, commit_transaction);
 776         if (err) {
 777                 printk(KERN_WARNING
 778                         "JBD2: Detected IO errors while flushing file data "
 779                        "on %s\n", journal->j_devname);
 780                 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
 781                         jbd2_journal_abort(journal, err);
 782                 err = 0;
 783         }
 784
 785         /*
 786          * Get current oldest transaction in the log before we issue flush
 787          * to the filesystem device. After the flush we can be sure that
 788          * blocks of all older transactions are checkpointed to persistent
 789          * storage and we will be safe to update journal start in the
 790          * superblock with the numbers we get here.
 791          */
 792         update_tail =
 793                 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
 794
 795         write_lock(&journal->j_state_lock);
 796         if (update_tail) {
 797                 long freed = first_block - journal->j_tail;
 798
 799                 if (first_block < journal->j_tail)
 800                         freed += journal->j_last - journal->j_first;
 801                 /* Update tail only if we free significant amount of space */
 802                 if (freed < jbd2_journal_get_max_txn_bufs(journal))
 803                         update_tail = 0;
 804         }
 805         J_ASSERT(commit_transaction->t_state == T_COMMIT);
 806         commit_transaction->t_state = T_COMMIT_DFLUSH;
 807         write_unlock(&journal->j_state_lock);
 808
 809         /*
 810          * If the journal is not located on the file system device,
 811          * then we must flush the file system device before we issue
 812          * the commit record
 813          */
 814         if (commit_transaction->t_need_data_flush &&
 815             (journal->j_fs_dev != journal->j_dev) &&
 816             (journal->j_flags & JBD2_BARRIER))
 817                 blkdev_issue_flush(journal->j_fs_dev);
 818
 819         /* Done it all: now write the commit record asynchronously. */
 820         if (jbd2_has_feature_async_commit(journal)) {
 821                 err = journal_submit_commit_record(journal, commit_transaction,
 822                                                  &cbh, crc32_sum);
 823                 if (err)
 824                         jbd2_journal_abort(journal, err);
 825         }
 826
 827         blk_finish_plug(&plug);
 828
 829         /* Lo and behold: we have just managed to send a transaction to
 830            the log.  Before we can commit it, wait for the IO so far to
 831            complete.  Control buffers being written are on the
 832            transaction's t_log_list queue, and metadata buffers are on
 833            the io_bufs list.
 834
 835            Wait for the buffers in reverse order.  That way we are
 836            less likely to be woken up until all IOs have completed, and
 837            so we incur less scheduling load.
 838         */
 839
 840         jbd2_debug(3, "JBD2: commit phase 3\n");
 841
 842         while (!list_empty(&io_bufs)) {
 843                 struct buffer_head *bh = list_entry(io_bufs.prev,
 844                                                     struct buffer_head,
 845                                                     b_assoc_buffers);
 846
 847                 wait_on_buffer(bh);
 848                 cond_resched();
 849
 850                 if (unlikely(!buffer_uptodate(bh)))
 851                         err = -EIO;
 852                 jbd2_unfile_log_bh(bh);
 853                 stats.run.rs_blocks_logged++;
 854
 855                 /*
 856                  * The list contains temporary buffer heads created by
 857                  * jbd2_journal_write_metadata_buffer().
 858                  */
 859                 BUFFER_TRACE(bh, "dumping temporary bh");
 860                 __brelse(bh);
 861                 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
 862                 free_buffer_head(bh);
 863
 864                 /* We also have to refile the corresponding shadowed buffer */
 865                 jh = commit_transaction->t_shadow_list->b_tprev;
 866                 bh = jh2bh(jh);
 867                 clear_buffer_jwrite(bh);
 868                 J_ASSERT_BH(bh, buffer_jbddirty(bh));
 869                 J_ASSERT_BH(bh, !buffer_shadow(bh));
 870
 871                 /* The metadata is now released for reuse, but we need
 872                    to remember it against this transaction so that when
 873                    we finally commit, we can do any checkpointing
 874                    required. */
 875                 JBUFFER_TRACE(jh, "file as BJ_Forget");
 876                 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
 877                 JBUFFER_TRACE(jh, "brelse shadowed buffer");
 878                 __brelse(bh);
 879         }
 880
 881         J_ASSERT (commit_transaction->t_shadow_list == NULL);
 882
 883         jbd2_debug(3, "JBD2: commit phase 4\n");
 884
 885         /* Here we wait for the revoke record and descriptor record buffers */
 886         while (!list_empty(&log_bufs)) {
 887                 struct buffer_head *bh;
 888
 889                 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
 890                 wait_on_buffer(bh);
 891                 cond_resched();
 892
 893                 if (unlikely(!buffer_uptodate(bh)))
 894                         err = -EIO;
 895
 896                 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
 897                 clear_buffer_jwrite(bh);
 898                 jbd2_unfile_log_bh(bh);
 899                 stats.run.rs_blocks_logged++;
 900                 __brelse(bh);           /* One for getblk */
 901                 /* AKPM: bforget here */
 902         }
 903
 904         if (err)
 905                 jbd2_journal_abort(journal, err);
 906
 907         jbd2_debug(3, "JBD2: commit phase 5\n");
 908         write_lock(&journal->j_state_lock);
 909         J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
 910         commit_transaction->t_state = T_COMMIT_JFLUSH;
 911         write_unlock(&journal->j_state_lock);
 912
 913         if (!jbd2_has_feature_async_commit(journal)) {
 914                 err = journal_submit_commit_record(journal, commit_transaction,
 915                                                 &cbh, crc32_sum);
 916                 if (err)
 917                         jbd2_journal_abort(journal, err);
 918         }
 919         if (cbh)
 920                 err = journal_wait_on_commit_record(journal, cbh);
 921         stats.run.rs_blocks_logged++;
 922         if (jbd2_has_feature_async_commit(journal) &&
 923             journal->j_flags & JBD2_BARRIER) {
 924                 blkdev_issue_flush(journal->j_dev);
 925         }
 926
 927         if (err)
 928                 jbd2_journal_abort(journal, err);
 929
 930         WARN_ON_ONCE(
 931                 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
 932
 933         /*
 934          * Now disk caches for filesystem device are flushed so we are safe to
 935          * erase checkpointed transactions from the log by updating journal
 936          * superblock.
 937          */
 938         if (update_tail)
 939                 jbd2_update_log_tail(journal, first_tid, first_block);
 940
 941         /* End of a transaction!  Finally, we can do checkpoint
 942            processing: any buffers committed as a result of this
 943            transaction can be removed from any checkpoint list it was on
 944            before. */
 945
 946         jbd2_debug(3, "JBD2: commit phase 6\n");
 947
 948         J_ASSERT(list_empty(&commit_transaction->t_inode_list));
 949         J_ASSERT(commit_transaction->t_buffers == NULL);
 950         J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
 951         J_ASSERT(commit_transaction->t_shadow_list == NULL);
 952
 953 restart_loop:
 954         /*
 955          * As there are other places (journal_unmap_buffer()) adding buffers
 956          * to this list we have to be careful and hold the j_list_lock.
 957          */
 958         spin_lock(&journal->j_list_lock);
 959         while (commit_transaction->t_forget) {
 960                 transaction_t *cp_transaction;
 961                 struct buffer_head *bh;
 962                 int try_to_free = 0;
 963                 bool drop_ref;
 964
 965                 jh = commit_transaction->t_forget;
 966                 spin_unlock(&journal->j_list_lock);
 967                 bh = jh2bh(jh);
 968                 /*
 969                  * Get a reference so that bh cannot be freed before we are
 970                  * done with it.
 971                  */
 972                 get_bh(bh);
 973                 spin_lock(&jh->b_state_lock);
 974                 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
 975
 976                 /*
 977                  * If there is undo-protected committed data against
 978                  * this buffer, then we can remove it now.  If it is a
 979                  * buffer needing such protection, the old frozen_data
 980                  * field now points to a committed version of the
 981                  * buffer, so rotate that field to the new committed
 982                  * data.
 983                  *
 984                  * Otherwise, we can just throw away the frozen data now.
 985                  *
 986                  * We also know that the frozen data has already fired
 987                  * its triggers if they exist, so we can clear that too.
 988                  */
 989                 if (jh->b_committed_data) {
 990                         jbd2_free(jh->b_committed_data, bh->b_size);
 991                         jh->b_committed_data = NULL;
 992                         if (jh->b_frozen_data) {
 993                                 jh->b_committed_data = jh->b_frozen_data;
 994                                 jh->b_frozen_data = NULL;
 995                                 jh->b_frozen_triggers = NULL;
 996                         }
 997                 } else if (jh->b_frozen_data) {
 998                         jbd2_free(jh->b_frozen_data, bh->b_size);
 999                         jh->b_frozen_data = NULL;
1000                         jh->b_frozen_triggers = NULL;
1001                 }
1002
1003                 spin_lock(&journal->j_list_lock);
1004                 cp_transaction = jh->b_cp_transaction;
1005                 if (cp_transaction) {
1006                         JBUFFER_TRACE(jh, "remove from old cp transaction");
1007                         cp_transaction->t_chp_stats.cs_dropped++;
1008                         __jbd2_journal_remove_checkpoint(jh);
1009                 }
1010
1011                 /* Only re-checkpoint the buffer_head if it is marked
1012                  * dirty.  If the buffer was added to the BJ_Forget list
1013                  * by jbd2_journal_forget, it may no longer be dirty and
1014                  * there's no point in keeping a checkpoint record for
1015                  * it. */
1016
1017                 /*
1018                  * A buffer which has been freed while still being journaled
1019                  * by a previous transaction, refile the buffer to BJ_Forget of
1020                  * the running transaction. If the just committed transaction
1021                  * contains "add to orphan" operation, we can completely
1022                  * invalidate the buffer now. We are rather through in that
1023                  * since the buffer may be still accessible when blocksize <
1024                  * pagesize and it is attached to the last partial page.
1025                  */
1026                 if (buffer_freed(bh) && !jh->b_next_transaction) {
1027                         struct address_space *mapping;
1028
1029                         clear_buffer_freed(bh);
1030                         clear_buffer_jbddirty(bh);
1031
1032                         /*
1033                          * Block device buffers need to stay mapped all the
1034                          * time, so it is enough to clear buffer_jbddirty and
1035                          * buffer_freed bits. For the file mapping buffers (i.e.
1036                          * journalled data) we need to unmap buffer and clear
1037                          * more bits. We also need to be careful about the check
1038                          * because the data page mapping can get cleared under
1039                          * our hands. Note that if mapping == NULL, we don't
1040                          * need to make buffer unmapped because the page is
1041                          * already detached from the mapping and buffers cannot
1042                          * get reused.
1043                          */
1044                         mapping = READ_ONCE(bh->b_page->mapping);
1045                         if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1046                                 clear_buffer_mapped(bh);
1047                                 clear_buffer_new(bh);
1048                                 clear_buffer_req(bh);
1049                                 bh->b_bdev = NULL;
1050                         }
1051                 }
1052
1053                 if (buffer_jbddirty(bh)) {
1054                         JBUFFER_TRACE(jh, "add to new checkpointing trans");
1055                         __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1056                         if (is_journal_aborted(journal))
1057                                 clear_buffer_jbddirty(bh);
1058                 } else {
1059                         J_ASSERT_BH(bh, !buffer_dirty(bh));
1060                         /*
1061                          * The buffer on BJ_Forget list and not jbddirty means
1062                          * it has been freed by this transaction and hence it
1063                          * could not have been reallocated until this
1064                          * transaction has committed. *BUT* it could be
1065                          * reallocated once we have written all the data to
1066                          * disk and before we process the buffer on BJ_Forget
1067                          * list.
1068                          */
1069                         if (!jh->b_next_transaction)
1070                                 try_to_free = 1;
1071                 }
1072                 JBUFFER_TRACE(jh, "refile or unfile buffer");
1073                 drop_ref = __jbd2_journal_refile_buffer(jh);
1074                 spin_unlock(&jh->b_state_lock);
1075                 if (drop_ref)
1076                         jbd2_journal_put_journal_head(jh);
1077                 if (try_to_free)
1078                         release_buffer_page(bh);        /* Drops bh reference */
1079                 else
1080                         __brelse(bh);
1081                 cond_resched_lock(&journal->j_list_lock);
1082         }
1083         spin_unlock(&journal->j_list_lock);
1084         /*
1085          * This is a bit sleazy.  We use j_list_lock to protect transition
1086          * of a transaction into T_FINISHED state and calling
1087          * __jbd2_journal_drop_transaction(). Otherwise we could race with
1088          * other checkpointing code processing the transaction...
1089          */
1090         write_lock(&journal->j_state_lock);
1091         spin_lock(&journal->j_list_lock);
1092         /*
1093          * Now recheck if some buffers did not get attached to the transaction
1094          * while the lock was dropped...
1095          */
1096         if (commit_transaction->t_forget) {
1097                 spin_unlock(&journal->j_list_lock);
1098                 write_unlock(&journal->j_state_lock);
1099                 goto restart_loop;
1100         }
1101
1102         /* Add the transaction to the checkpoint list
1103          * __journal_remove_checkpoint() can not destroy transaction
1104          * under us because it is not marked as T_FINISHED yet */
1105         if (journal->j_checkpoint_transactions == NULL) {
1106                 journal->j_checkpoint_transactions = commit_transaction;
1107                 commit_transaction->t_cpnext = commit_transaction;
1108                 commit_transaction->t_cpprev = commit_transaction;
1109         } else {
1110                 commit_transaction->t_cpnext =
1111                         journal->j_checkpoint_transactions;
1112                 commit_transaction->t_cpprev =
1113                         commit_transaction->t_cpnext->t_cpprev;
1114                 commit_transaction->t_cpnext->t_cpprev =
1115                         commit_transaction;
1116                 commit_transaction->t_cpprev->t_cpnext =
1117                                 commit_transaction;
1118         }
1119         spin_unlock(&journal->j_list_lock);
1120
1121         /* Done with this transaction! */
1122
1123         jbd2_debug(3, "JBD2: commit phase 7\n");
1124
1125         J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1126
1127         commit_transaction->t_start = jiffies;
1128         stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1129                                               commit_transaction->t_start);
1130
1131         /*
1132          * File the transaction statistics
1133          */
1134         stats.ts_tid = commit_transaction->t_tid;
1135         stats.run.rs_handle_count =
1136                 atomic_read(&commit_transaction->t_handle_count);
1137         trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1138                              commit_transaction->t_tid, &stats.run);
1139         stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1140
1141         commit_transaction->t_state = T_COMMIT_CALLBACK;
1142         J_ASSERT(commit_transaction == journal->j_committing_transaction);
1143         journal->j_commit_sequence = commit_transaction->t_tid;
1144         journal->j_committing_transaction = NULL;
1145         commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1146
1147         /*
1148          * weight the commit time higher than the average time so we don't
1149          * react too strongly to vast changes in the commit time
1150          */
1151         if (likely(journal->j_average_commit_time))
1152                 journal->j_average_commit_time = (commit_time +
1153                                 journal->j_average_commit_time*3) / 4;
1154         else
1155                 journal->j_average_commit_time = commit_time;
1156
1157         write_unlock(&journal->j_state_lock);
1158
1159         if (journal->j_commit_callback)
1160                 journal->j_commit_callback(journal, commit_transaction);
1161         if (journal->j_fc_cleanup_callback)
1162                 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1163
1164         trace_jbd2_end_commit(journal, commit_transaction);
1165         jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1166                   journal->j_commit_sequence, journal->j_tail_sequence);
1167
1168         write_lock(&journal->j_state_lock);
1169         journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1170         journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1171         spin_lock(&journal->j_list_lock);
1172         commit_transaction->t_state = T_FINISHED;
1173         /* Check if the transaction can be dropped now that we are finished */
1174         if (commit_transaction->t_checkpoint_list == NULL &&
1175             commit_transaction->t_checkpoint_io_list == NULL) {
1176                 __jbd2_journal_drop_transaction(journal, commit_transaction);
1177                 jbd2_journal_free_transaction(commit_transaction);
1178         }
1179         spin_unlock(&journal->j_list_lock);
1180         write_unlock(&journal->j_state_lock);
1181         wake_up(&journal->j_wait_done_commit);
1182         wake_up(&journal->j_fc_wait);
1183
1184         /*
1185          * Calculate overall stats
1186          */
1187         spin_lock(&journal->j_history_lock);
1188         journal->j_stats.ts_tid++;
1189         journal->j_stats.ts_requested += stats.ts_requested;
1190         journal->j_stats.run.rs_wait += stats.run.rs_wait;
1191         journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1192         journal->j_stats.run.rs_running += stats.run.rs_running;
1193         journal->j_stats.run.rs_locked += stats.run.rs_locked;
1194         journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1195         journal->j_stats.run.rs_logging += stats.run.rs_logging;
1196         journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1197         journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1198         journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1199         spin_unlock(&journal->j_history_lock);
1200 }