LCOV - code coverage report
Current view: top level - fs/jbd2 - commit.c (source / functions) Hit Total Coverage
Test: combined.info Lines: 392 551 71.1 %
Date: 2022-04-01 13:59:58 Functions: 6 9 66.7 %
Branches: 117 262 44.7 %

           Branch data     Line data    Source code
       1                 :            : // SPDX-License-Identifier: GPL-2.0+
       2                 :            : /*
       3                 :            :  * linux/fs/jbd2/commit.c
       4                 :            :  *
       5                 :            :  * Written by Stephen C. Tweedie <sct@redhat.com>, 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                 :       8342 : static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
      33                 :            : {
      34                 :       8342 :         struct buffer_head *orig_bh = bh->b_private;
      35                 :            : 
      36                 :       8342 :         BUFFER_TRACE(bh, "");
      37         [ +  - ]:       8342 :         if (uptodate)
      38                 :       8342 :                 set_buffer_uptodate(bh);
      39                 :            :         else
      40                 :          0 :                 clear_buffer_uptodate(bh);
      41         [ +  + ]:       8342 :         if (orig_bh) {
      42                 :       7224 :                 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
      43                 :       7224 :                 smp_mb__after_atomic();
      44                 :       7224 :                 wake_up_bit(&orig_bh->b_state, BH_Shadow);
      45                 :            :         }
      46                 :       8342 :         unlock_buffer(bh);
      47                 :       8342 : }
      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                 :          0 : static void release_buffer_page(struct buffer_head *bh)
      64                 :            : {
      65                 :          0 :         struct page *page;
      66                 :            : 
      67         [ #  # ]:          0 :         if (buffer_dirty(bh))
      68                 :          0 :                 goto nope;
      69         [ #  # ]:          0 :         if (atomic_read(&bh->b_count) != 1)
      70                 :          0 :                 goto nope;
      71                 :          0 :         page = bh->b_page;
      72         [ #  # ]:          0 :         if (!page)
      73                 :          0 :                 goto nope;
      74         [ #  # ]:          0 :         if (page->mapping)
      75                 :          0 :                 goto nope;
      76                 :            : 
      77                 :            :         /* OK, it's a truncated page */
      78   [ #  #  #  # ]:          0 :         if (!trylock_page(page))
      79                 :          0 :                 goto nope;
      80                 :            : 
      81         [ #  # ]:          0 :         get_page(page);
      82                 :          0 :         __brelse(bh);
      83                 :          0 :         try_to_free_buffers(page);
      84                 :          0 :         unlock_page(page);
      85                 :          0 :         put_page(page);
      86                 :          0 :         return;
      87                 :            : 
      88                 :          0 : nope:
      89                 :          0 :         __brelse(bh);
      90                 :            : }
      91                 :            : 
      92                 :            : static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
      93                 :            : {
      94                 :            :         struct commit_header *h;
      95                 :            :         __u32 csum;
      96                 :            : 
      97                 :            :         if (!jbd2_journal_has_csum_v2or3(j))
      98                 :            :                 return;
      99                 :            : 
     100                 :            :         h = (struct commit_header *)(bh->b_data);
     101                 :            :         h->h_chksum_type = 0;
     102                 :            :         h->h_chksum_size = 0;
     103                 :            :         h->h_chksum[0] = 0;
     104                 :            :         csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
     105                 :            :         h->h_chksum[0] = cpu_to_be32(csum);
     106                 :            : }
     107                 :            : 
     108                 :            : /*
     109                 :            :  * Done it all: now submit the commit record.  We should have
     110                 :            :  * cleaned up our previous buffers by now, so if we are in abort
     111                 :            :  * mode we can now just skip the rest of the journal write
     112                 :            :  * entirely.
     113                 :            :  *
     114                 :            :  * Returns 1 if the journal needs to be aborted or 0 on success
     115                 :            :  */
     116                 :        559 : static int journal_submit_commit_record(journal_t *journal,
     117                 :            :                                         transaction_t *commit_transaction,
     118                 :            :                                         struct buffer_head **cbh,
     119                 :            :                                         __u32 crc32_sum)
     120                 :            : {
     121                 :        559 :         struct commit_header *tmp;
     122                 :        559 :         struct buffer_head *bh;
     123                 :        559 :         int ret;
     124                 :        559 :         struct timespec64 now;
     125                 :            : 
     126                 :        559 :         *cbh = NULL;
     127                 :            : 
     128         [ +  - ]:        559 :         if (is_journal_aborted(journal))
     129                 :            :                 return 0;
     130                 :            : 
     131                 :        559 :         bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
     132                 :            :                                                 JBD2_COMMIT_BLOCK);
     133         [ +  - ]:        559 :         if (!bh)
     134                 :            :                 return 1;
     135                 :            : 
     136                 :        559 :         tmp = (struct commit_header *)bh->b_data;
     137                 :        559 :         ktime_get_coarse_real_ts64(&now);
     138                 :        559 :         tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
     139                 :        559 :         tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
     140                 :            : 
     141   [ +  -  -  + ]:       1118 :         if (jbd2_has_feature_checksum(journal)) {
     142                 :          0 :                 tmp->h_chksum_type   = JBD2_CRC32_CHKSUM;
     143                 :          0 :                 tmp->h_chksum_size   = JBD2_CRC32_CHKSUM_SIZE;
     144                 :          0 :                 tmp->h_chksum[0]     = cpu_to_be32(crc32_sum);
     145                 :            :         }
     146                 :        559 :         jbd2_commit_block_csum_set(journal, bh);
     147                 :            : 
     148                 :        559 :         BUFFER_TRACE(bh, "submit commit block");
     149                 :        559 :         lock_buffer(bh);
     150                 :        559 :         clear_buffer_dirty(bh);
     151                 :        559 :         set_buffer_uptodate(bh);
     152                 :        559 :         bh->b_end_io = journal_end_buffer_io_sync;
     153                 :            : 
     154   [ +  -  +  - ]:       1118 :         if (journal->j_flags & JBD2_BARRIER &&
     155         [ +  - ]:        559 :             !jbd2_has_feature_async_commit(journal))
     156                 :        559 :                 ret = submit_bh(REQ_OP_WRITE,
     157                 :            :                         REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
     158                 :            :         else
     159                 :          0 :                 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
     160                 :            : 
     161                 :        559 :         *cbh = bh;
     162                 :        559 :         return ret;
     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                 :          0 : static int journal_submit_inode_data_buffers(struct address_space *mapping,
     191                 :            :                 loff_t dirty_start, loff_t dirty_end)
     192                 :            : {
     193                 :          0 :         int ret;
     194                 :          0 :         struct writeback_control wbc = {
     195                 :            :                 .sync_mode =  WB_SYNC_ALL,
     196                 :          0 :                 .nr_to_write = mapping->nrpages * 2,
     197                 :            :                 .range_start = dirty_start,
     198                 :            :                 .range_end = dirty_end,
     199                 :            :         };
     200                 :            : 
     201                 :          0 :         ret = generic_writepages(mapping, &wbc);
     202                 :          0 :         return ret;
     203                 :            : }
     204                 :            : 
     205                 :            : /*
     206                 :            :  * Submit all the data buffers of inode associated with the transaction to
     207                 :            :  * disk.
     208                 :            :  *
     209                 :            :  * We are in a committing transaction. Therefore no new inode can be added to
     210                 :            :  * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
     211                 :            :  * operate on from being released while we write out pages.
     212                 :            :  */
     213                 :        559 : static int journal_submit_data_buffers(journal_t *journal,
     214                 :            :                 transaction_t *commit_transaction)
     215                 :            : {
     216                 :        559 :         struct jbd2_inode *jinode;
     217                 :        559 :         int err, ret = 0;
     218                 :        559 :         struct address_space *mapping;
     219                 :            : 
     220                 :        559 :         spin_lock(&journal->j_list_lock);
     221         [ -  + ]:        559 :         list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
     222                 :          0 :                 loff_t dirty_start = jinode->i_dirty_start;
     223                 :          0 :                 loff_t dirty_end = jinode->i_dirty_end;
     224                 :            : 
     225         [ #  # ]:          0 :                 if (!(jinode->i_flags & JI_WRITE_DATA))
     226                 :          0 :                         continue;
     227                 :          0 :                 mapping = jinode->i_vfs_inode->i_mapping;
     228                 :          0 :                 jinode->i_flags |= JI_COMMIT_RUNNING;
     229                 :          0 :                 spin_unlock(&journal->j_list_lock);
     230                 :            :                 /*
     231                 :            :                  * submit the inode data buffers. We use writepage
     232                 :            :                  * instead of writepages. Because writepages can do
     233                 :            :                  * block allocation  with delalloc. We need to write
     234                 :            :                  * only allocated blocks here.
     235                 :            :                  */
     236                 :          0 :                 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
     237                 :          0 :                 err = journal_submit_inode_data_buffers(mapping, dirty_start,
     238                 :            :                                 dirty_end);
     239         [ #  # ]:          0 :                 if (!ret)
     240                 :          0 :                         ret = err;
     241                 :          0 :                 spin_lock(&journal->j_list_lock);
     242         [ #  # ]:          0 :                 J_ASSERT(jinode->i_transaction == commit_transaction);
     243                 :          0 :                 jinode->i_flags &= ~JI_COMMIT_RUNNING;
     244                 :          0 :                 smp_mb();
     245                 :          0 :                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
     246                 :            :         }
     247                 :        559 :         spin_unlock(&journal->j_list_lock);
     248                 :        559 :         return ret;
     249                 :            : }
     250                 :            : 
     251                 :            : /*
     252                 :            :  * Wait for data submitted for writeout, refile inodes to proper
     253                 :            :  * transaction if needed.
     254                 :            :  *
     255                 :            :  */
     256                 :        559 : static int journal_finish_inode_data_buffers(journal_t *journal,
     257                 :            :                 transaction_t *commit_transaction)
     258                 :            : {
     259                 :        559 :         struct jbd2_inode *jinode, *next_i;
     260                 :        559 :         int err, ret = 0;
     261                 :            : 
     262                 :            :         /* For locking, see the comment in journal_submit_data_buffers() */
     263                 :        559 :         spin_lock(&journal->j_list_lock);
     264         [ -  + ]:        559 :         list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
     265                 :          0 :                 loff_t dirty_start = jinode->i_dirty_start;
     266                 :          0 :                 loff_t dirty_end = jinode->i_dirty_end;
     267                 :            : 
     268         [ #  # ]:          0 :                 if (!(jinode->i_flags & JI_WAIT_DATA))
     269                 :          0 :                         continue;
     270                 :          0 :                 jinode->i_flags |= JI_COMMIT_RUNNING;
     271                 :          0 :                 spin_unlock(&journal->j_list_lock);
     272                 :          0 :                 err = filemap_fdatawait_range_keep_errors(
     273                 :          0 :                                 jinode->i_vfs_inode->i_mapping, dirty_start,
     274                 :            :                                 dirty_end);
     275         [ #  # ]:          0 :                 if (!ret)
     276                 :          0 :                         ret = err;
     277                 :          0 :                 spin_lock(&journal->j_list_lock);
     278                 :          0 :                 jinode->i_flags &= ~JI_COMMIT_RUNNING;
     279                 :          0 :                 smp_mb();
     280                 :          0 :                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
     281                 :            :         }
     282                 :            : 
     283                 :            :         /* Now refile inode to proper lists */
     284         [ -  + ]:        559 :         list_for_each_entry_safe(jinode, next_i,
     285                 :            :                                  &commit_transaction->t_inode_list, i_list) {
     286         [ #  # ]:          0 :                 list_del(&jinode->i_list);
     287         [ #  # ]:          0 :                 if (jinode->i_next_transaction) {
     288                 :          0 :                         jinode->i_transaction = jinode->i_next_transaction;
     289                 :          0 :                         jinode->i_next_transaction = NULL;
     290                 :          0 :                         list_add(&jinode->i_list,
     291                 :            :                                 &jinode->i_transaction->t_inode_list);
     292                 :            :                 } else {
     293                 :          0 :                         jinode->i_transaction = NULL;
     294                 :          0 :                         jinode->i_dirty_start = 0;
     295                 :          0 :                         jinode->i_dirty_end = 0;
     296                 :            :                 }
     297                 :            :         }
     298                 :        559 :         spin_unlock(&journal->j_list_lock);
     299                 :            : 
     300                 :        559 :         return ret;
     301                 :            : }
     302                 :            : 
     303                 :          0 : static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
     304                 :            : {
     305                 :          0 :         struct page *page = bh->b_page;
     306                 :          0 :         char *addr;
     307                 :          0 :         __u32 checksum;
     308                 :            : 
     309                 :          0 :         addr = kmap_atomic(page);
     310                 :          0 :         checksum = crc32_be(crc32_sum,
     311                 :          0 :                 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
     312                 :          0 :         kunmap_atomic(addr);
     313                 :            : 
     314                 :          0 :         return checksum;
     315                 :            : }
     316                 :            : 
     317                 :       7224 : static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
     318                 :            :                                    unsigned long long block)
     319                 :            : {
     320                 :       7224 :         tag->t_blocknr = cpu_to_be32(block & (u32)~0);
     321   [ +  -  +  - ]:      14448 :         if (jbd2_has_feature_64bit(j))
     322                 :       7224 :                 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
     323                 :            : }
     324                 :            : 
     325                 :       7224 : static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
     326                 :            :                                     struct buffer_head *bh, __u32 sequence)
     327                 :            : {
     328                 :       7224 :         journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
     329                 :       7224 :         struct page *page = bh->b_page;
     330                 :       7224 :         __u8 *addr;
     331                 :       7224 :         __u32 csum32;
     332                 :       7224 :         __be32 seq;
     333                 :            : 
     334         [ -  + ]:       7224 :         if (!jbd2_journal_has_csum_v2or3(j))
     335                 :          0 :                 return;
     336                 :            : 
     337                 :       7224 :         seq = cpu_to_be32(sequence);
     338                 :       7224 :         addr = kmap_atomic(page);
     339                 :       7224 :         csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
     340                 :       7224 :         csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
     341                 :       7224 :                              bh->b_size);
     342                 :       7224 :         kunmap_atomic(addr);
     343                 :            : 
     344   [ +  -  +  - ]:      14448 :         if (jbd2_has_feature_csum3(j))
     345                 :       7224 :                 tag3->t_checksum = cpu_to_be32(csum32);
     346                 :            :         else
     347                 :          0 :                 tag->t_checksum = cpu_to_be16(csum32);
     348                 :            : }
     349                 :            : /*
     350                 :            :  * jbd2_journal_commit_transaction
     351                 :            :  *
     352                 :            :  * The primary function for committing a transaction to the log.  This
     353                 :            :  * function is called by the journal thread to begin a complete commit.
     354                 :            :  */
     355                 :        559 : void jbd2_journal_commit_transaction(journal_t *journal)
     356                 :            : {
     357                 :        559 :         struct transaction_stats_s stats;
     358                 :        559 :         transaction_t *commit_transaction;
     359                 :        559 :         struct journal_head *jh;
     360                 :        559 :         struct buffer_head *descriptor;
     361                 :        559 :         struct buffer_head **wbuf = journal->j_wbuf;
     362                 :        559 :         int bufs;
     363                 :        559 :         int flags;
     364                 :        559 :         int err;
     365                 :        559 :         unsigned long long blocknr;
     366                 :        559 :         ktime_t start_time;
     367                 :        559 :         u64 commit_time;
     368                 :        559 :         char *tagp = NULL;
     369                 :        559 :         journal_block_tag_t *tag = NULL;
     370                 :        559 :         int space_left = 0;
     371                 :        559 :         int first_tag = 0;
     372                 :        559 :         int tag_flag;
     373                 :        559 :         int i;
     374                 :        559 :         int tag_bytes = journal_tag_bytes(journal);
     375                 :        559 :         struct buffer_head *cbh = NULL; /* For transactional checksums */
     376                 :        559 :         __u32 crc32_sum = ~0;
     377                 :        559 :         struct blk_plug plug;
     378                 :            :         /* Tail of the journal */
     379                 :        559 :         unsigned long first_block;
     380                 :        559 :         tid_t first_tid;
     381                 :        559 :         int update_tail;
     382                 :        559 :         int csum_size = 0;
     383                 :        559 :         LIST_HEAD(io_bufs);
     384                 :        559 :         LIST_HEAD(log_bufs);
     385                 :            : 
     386         [ +  - ]:        559 :         if (jbd2_journal_has_csum_v2or3(journal))
     387                 :        559 :                 csum_size = sizeof(struct jbd2_journal_block_tail);
     388                 :            : 
     389                 :            :         /*
     390                 :            :          * First job: lock down the current transaction and wait for
     391                 :            :          * all outstanding updates to complete.
     392                 :            :          */
     393                 :            : 
     394                 :            :         /* Do we need to erase the effects of a prior jbd2_journal_flush? */
     395         [ +  + ]:        559 :         if (journal->j_flags & JBD2_FLUSHED) {
     396                 :         78 :                 jbd_debug(3, "super block updated\n");
     397                 :         78 :                 mutex_lock_io(&journal->j_checkpoint_mutex);
     398                 :            :                 /*
     399                 :            :                  * We hold j_checkpoint_mutex so tail cannot change under us.
     400                 :            :                  * We don't need any special data guarantees for writing sb
     401                 :            :                  * since journal is empty and it is ok for write to be
     402                 :            :                  * flushed only with transaction commit.
     403                 :            :                  */
     404                 :         78 :                 jbd2_journal_update_sb_log_tail(journal,
     405                 :            :                                                 journal->j_tail_sequence,
     406                 :            :                                                 journal->j_tail,
     407                 :            :                                                 REQ_SYNC);
     408                 :         78 :                 mutex_unlock(&journal->j_checkpoint_mutex);
     409                 :            :         } else {
     410                 :        559 :                 jbd_debug(3, "superblock not updated\n");
     411                 :            :         }
     412                 :            : 
     413         [ -  + ]:        559 :         J_ASSERT(journal->j_running_transaction != NULL);
     414         [ -  + ]:        559 :         J_ASSERT(journal->j_committing_transaction == NULL);
     415                 :            : 
     416                 :        559 :         commit_transaction = journal->j_running_transaction;
     417                 :            : 
     418                 :        559 :         trace_jbd2_start_commit(journal, commit_transaction);
     419                 :            :         jbd_debug(1, "JBD2: starting commit of transaction %d\n",
     420                 :        559 :                         commit_transaction->t_tid);
     421                 :            : 
     422                 :        559 :         write_lock(&journal->j_state_lock);
     423         [ -  + ]:        559 :         J_ASSERT(commit_transaction->t_state == T_RUNNING);
     424                 :        559 :         commit_transaction->t_state = T_LOCKED;
     425                 :            : 
     426                 :        559 :         trace_jbd2_commit_locking(journal, commit_transaction);
     427                 :        559 :         stats.run.rs_wait = commit_transaction->t_max_wait;
     428                 :        559 :         stats.run.rs_request_delay = 0;
     429                 :        559 :         stats.run.rs_locked = jiffies;
     430         [ +  - ]:        559 :         if (commit_transaction->t_requested)
     431         [ +  - ]:       1118 :                 stats.run.rs_request_delay =
     432                 :            :                         jbd2_time_diff(commit_transaction->t_requested,
     433                 :            :                                        stats.run.rs_locked);
     434         [ +  - ]:        559 :         stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
     435                 :            :                                               stats.run.rs_locked);
     436                 :            : 
     437                 :        559 :         spin_lock(&commit_transaction->t_handle_lock);
     438         [ +  + ]:        560 :         while (atomic_read(&commit_transaction->t_updates)) {
     439                 :          1 :                 DEFINE_WAIT(wait);
     440                 :            : 
     441                 :          1 :                 prepare_to_wait(&journal->j_wait_updates, &wait,
     442                 :            :                                         TASK_UNINTERRUPTIBLE);
     443         [ +  - ]:          1 :                 if (atomic_read(&commit_transaction->t_updates)) {
     444                 :          1 :                         spin_unlock(&commit_transaction->t_handle_lock);
     445                 :          1 :                         write_unlock(&journal->j_state_lock);
     446                 :          1 :                         schedule();
     447                 :          1 :                         write_lock(&journal->j_state_lock);
     448                 :          1 :                         spin_lock(&commit_transaction->t_handle_lock);
     449                 :            :                 }
     450                 :          1 :                 finish_wait(&journal->j_wait_updates, &wait);
     451                 :            :         }
     452                 :        559 :         spin_unlock(&commit_transaction->t_handle_lock);
     453                 :        559 :         commit_transaction->t_state = T_SWITCH;
     454                 :        559 :         write_unlock(&journal->j_state_lock);
     455                 :            : 
     456         [ -  + ]:        559 :         J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
     457                 :            :                         journal->j_max_transaction_buffers);
     458                 :            : 
     459                 :            :         /*
     460                 :            :          * First thing we are allowed to do is to discard any remaining
     461                 :            :          * BJ_Reserved buffers.  Note, it is _not_ permissible to assume
     462                 :            :          * that there are no such buffers: if a large filesystem
     463                 :            :          * operation like a truncate needs to split itself over multiple
     464                 :            :          * transactions, then it may try to do a jbd2_journal_restart() while
     465                 :            :          * there are still BJ_Reserved buffers outstanding.  These must
     466                 :            :          * be released cleanly from the current transaction.
     467                 :            :          *
     468                 :            :          * In this case, the filesystem must still reserve write access
     469                 :            :          * again before modifying the buffer in the new transaction, but
     470                 :            :          * we do not require it to remember exactly which old buffers it
     471                 :            :          * has reserved.  This is consistent with the existing behaviour
     472                 :            :          * that multiple jbd2_journal_get_write_access() calls to the same
     473                 :            :          * buffer are perfectly permissible.
     474                 :            :          */
     475         [ -  + ]:        559 :         while (commit_transaction->t_reserved_list) {
     476                 :          0 :                 jh = commit_transaction->t_reserved_list;
     477                 :          0 :                 JBUFFER_TRACE(jh, "reserved, unused: refile");
     478                 :            :                 /*
     479                 :            :                  * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
     480                 :            :                  * leave undo-committed data.
     481                 :            :                  */
     482         [ #  # ]:          0 :                 if (jh->b_committed_data) {
     483                 :          0 :                         struct buffer_head *bh = jh2bh(jh);
     484                 :            : 
     485                 :          0 :                         spin_lock(&jh->b_state_lock);
     486                 :          0 :                         jbd2_free(jh->b_committed_data, bh->b_size);
     487                 :          0 :                         jh->b_committed_data = NULL;
     488                 :          0 :                         spin_unlock(&jh->b_state_lock);
     489                 :            :                 }
     490                 :          0 :                 jbd2_journal_refile_buffer(journal, jh);
     491                 :            :         }
     492                 :            : 
     493                 :            :         /*
     494                 :            :          * Now try to drop any written-back buffers from the journal's
     495                 :            :          * checkpoint lists.  We do this *before* commit because it potentially
     496                 :            :          * frees some memory
     497                 :            :          */
     498                 :        559 :         spin_lock(&journal->j_list_lock);
     499                 :        559 :         __jbd2_journal_clean_checkpoint_list(journal, false);
     500                 :        559 :         spin_unlock(&journal->j_list_lock);
     501                 :            : 
     502                 :        559 :         jbd_debug(3, "JBD2: commit phase 1\n");
     503                 :            : 
     504                 :            :         /*
     505                 :            :          * Clear revoked flag to reflect there is no revoked buffers
     506                 :            :          * in the next transaction which is going to be started.
     507                 :            :          */
     508                 :        559 :         jbd2_clear_buffer_revoked_flags(journal);
     509                 :            : 
     510                 :            :         /*
     511                 :            :          * Switch to a new revoke table.
     512                 :            :          */
     513                 :        559 :         jbd2_journal_switch_revoke_table(journal);
     514                 :            : 
     515                 :            :         /*
     516                 :            :          * Reserved credits cannot be claimed anymore, free them
     517                 :            :          */
     518                 :        559 :         atomic_sub(atomic_read(&journal->j_reserved_credits),
     519                 :            :                    &commit_transaction->t_outstanding_credits);
     520                 :            : 
     521                 :        559 :         write_lock(&journal->j_state_lock);
     522                 :        559 :         trace_jbd2_commit_flushing(journal, commit_transaction);
     523                 :        559 :         stats.run.rs_flushing = jiffies;
     524         [ +  - ]:        559 :         stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
     525                 :            :                                              stats.run.rs_flushing);
     526                 :            : 
     527                 :        559 :         commit_transaction->t_state = T_FLUSH;
     528                 :        559 :         journal->j_committing_transaction = commit_transaction;
     529                 :        559 :         journal->j_running_transaction = NULL;
     530                 :        559 :         start_time = ktime_get();
     531                 :        559 :         commit_transaction->t_log_start = journal->j_head;
     532                 :        559 :         wake_up(&journal->j_wait_transaction_locked);
     533                 :        559 :         write_unlock(&journal->j_state_lock);
     534                 :            : 
     535                 :        559 :         jbd_debug(3, "JBD2: commit phase 2a\n");
     536                 :            : 
     537                 :            :         /*
     538                 :            :          * Now start flushing things to disk, in the order they appear
     539                 :            :          * on the transaction lists.  Data blocks go first.
     540                 :            :          */
     541                 :        559 :         err = journal_submit_data_buffers(journal, commit_transaction);
     542         [ -  + ]:        559 :         if (err)
     543                 :          0 :                 jbd2_journal_abort(journal, err);
     544                 :            : 
     545                 :        559 :         blk_start_plug(&plug);
     546                 :        559 :         jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
     547                 :            : 
     548                 :        559 :         jbd_debug(3, "JBD2: commit phase 2b\n");
     549                 :            : 
     550                 :            :         /*
     551                 :            :          * Way to go: we have now written out all of the data for a
     552                 :            :          * transaction!  Now comes the tricky part: we need to write out
     553                 :            :          * metadata.  Loop over the transaction's entire buffer list:
     554                 :            :          */
     555                 :        559 :         write_lock(&journal->j_state_lock);
     556                 :        559 :         commit_transaction->t_state = T_COMMIT;
     557                 :        559 :         write_unlock(&journal->j_state_lock);
     558                 :            : 
     559                 :        559 :         trace_jbd2_commit_logging(journal, commit_transaction);
     560                 :        559 :         stats.run.rs_logging = jiffies;
     561         [ +  - ]:        559 :         stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
     562                 :            :                                                stats.run.rs_logging);
     563                 :        559 :         stats.run.rs_blocks = commit_transaction->t_nr_buffers;
     564                 :        559 :         stats.run.rs_blocks_logged = 0;
     565                 :            : 
     566         [ -  + ]:        559 :         J_ASSERT(commit_transaction->t_nr_buffers <=
     567                 :            :                  atomic_read(&commit_transaction->t_outstanding_credits));
     568                 :            : 
     569                 :            :         err = 0;
     570                 :            :         bufs = 0;
     571                 :            :         descriptor = NULL;
     572         [ +  + ]:       7783 :         while (commit_transaction->t_buffers) {
     573                 :            : 
     574                 :            :                 /* Find the next buffer to be journaled... */
     575                 :            : 
     576                 :       7224 :                 jh = commit_transaction->t_buffers;
     577                 :            : 
     578                 :            :                 /* If we're in abort mode, we just un-journal the buffer and
     579                 :            :                    release it. */
     580                 :            : 
     581         [ -  + ]:       7224 :                 if (is_journal_aborted(journal)) {
     582                 :          0 :                         clear_buffer_jbddirty(jh2bh(jh));
     583                 :          0 :                         JBUFFER_TRACE(jh, "journal is aborting: refile");
     584                 :          0 :                         jbd2_buffer_abort_trigger(jh,
     585         [ #  # ]:          0 :                                                   jh->b_frozen_data ?
     586                 :            :                                                   jh->b_frozen_triggers :
     587                 :            :                                                   jh->b_triggers);
     588                 :          0 :                         jbd2_journal_refile_buffer(journal, jh);
     589                 :            :                         /* If that was the last one, we need to clean up
     590                 :            :                          * any descriptor buffers which may have been
     591                 :            :                          * already allocated, even if we are now
     592                 :            :                          * aborting. */
     593         [ #  # ]:          0 :                         if (!commit_transaction->t_buffers)
     594                 :          0 :                                 goto start_journal_io;
     595                 :          0 :                         continue;
     596                 :            :                 }
     597                 :            : 
     598                 :            :                 /* Make sure we have a descriptor block in which to
     599                 :            :                    record the metadata buffer. */
     600                 :            : 
     601         [ +  + ]:       7224 :                 if (!descriptor) {
     602         [ -  + ]:        559 :                         J_ASSERT (bufs == 0);
     603                 :            : 
     604                 :        559 :                         jbd_debug(4, "JBD2: get descriptor\n");
     605                 :            : 
     606                 :        559 :                         descriptor = jbd2_journal_get_descriptor_buffer(
     607                 :            :                                                         commit_transaction,
     608                 :            :                                                         JBD2_DESCRIPTOR_BLOCK);
     609         [ -  + ]:        559 :                         if (!descriptor) {
     610                 :          0 :                                 jbd2_journal_abort(journal, -EIO);
     611                 :          0 :                                 continue;
     612                 :            :                         }
     613                 :            : 
     614                 :            :                         jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
     615                 :            :                                 (unsigned long long)descriptor->b_blocknr,
     616                 :        559 :                                 descriptor->b_data);
     617                 :        559 :                         tagp = &descriptor->b_data[sizeof(journal_header_t)];
     618                 :        559 :                         space_left = descriptor->b_size -
     619                 :            :                                                 sizeof(journal_header_t);
     620                 :        559 :                         first_tag = 1;
     621                 :        559 :                         set_buffer_jwrite(descriptor);
     622                 :        559 :                         set_buffer_dirty(descriptor);
     623                 :        559 :                         wbuf[bufs++] = descriptor;
     624                 :            : 
     625                 :            :                         /* Record it so that we can wait for IO
     626                 :            :                            completion later */
     627                 :        559 :                         BUFFER_TRACE(descriptor, "ph3: file as descriptor");
     628                 :        559 :                         jbd2_file_log_bh(&log_bufs, descriptor);
     629                 :            :                 }
     630                 :            : 
     631                 :            :                 /* Where is the buffer to be written? */
     632                 :            : 
     633                 :       7224 :                 err = jbd2_journal_next_log_block(journal, &blocknr);
     634                 :            :                 /* If the block mapping failed, just abandon the buffer
     635                 :            :                    and repeat this loop: we'll fall into the
     636                 :            :                    refile-on-abort condition above. */
     637         [ -  + ]:       7224 :                 if (err) {
     638                 :          0 :                         jbd2_journal_abort(journal, err);
     639                 :          0 :                         continue;
     640                 :            :                 }
     641                 :            : 
     642                 :            :                 /*
     643                 :            :                  * start_this_handle() uses t_outstanding_credits to determine
     644                 :            :                  * the free space in the log.
     645                 :            :                  */
     646                 :       7224 :                 atomic_dec(&commit_transaction->t_outstanding_credits);
     647                 :            : 
     648                 :            :                 /* Bump b_count to prevent truncate from stumbling over
     649                 :            :                    the shadowed buffer!  @@@ This can go if we ever get
     650                 :            :                    rid of the shadow pairing of buffers. */
     651                 :       7224 :                 atomic_inc(&jh2bh(jh)->b_count);
     652                 :            : 
     653                 :            :                 /*
     654                 :            :                  * Make a temporary IO buffer with which to write it out
     655                 :            :                  * (this will requeue the metadata buffer to BJ_Shadow).
     656                 :            :                  */
     657                 :       7224 :                 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
     658                 :       7224 :                 JBUFFER_TRACE(jh, "ph3: write metadata");
     659                 :       7224 :                 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
     660                 :       7224 :                                                 jh, &wbuf[bufs], blocknr);
     661         [ -  + ]:       7224 :                 if (flags < 0) {
     662                 :          0 :                         jbd2_journal_abort(journal, flags);
     663                 :          0 :                         continue;
     664                 :            :                 }
     665         [ +  + ]:       7224 :                 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
     666                 :            : 
     667                 :            :                 /* Record the new block's tag in the current descriptor
     668                 :            :                    buffer */
     669                 :            : 
     670                 :       7224 :                 tag_flag = 0;
     671                 :       7224 :                 if (flags & 1)
     672                 :            :                         tag_flag |= JBD2_FLAG_ESCAPE;
     673         [ +  + ]:       7224 :                 if (!first_tag)
     674                 :       6665 :                         tag_flag |= JBD2_FLAG_SAME_UUID;
     675                 :            : 
     676                 :       7224 :                 tag = (journal_block_tag_t *) tagp;
     677         [ +  - ]:       7224 :                 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
     678                 :       7224 :                 tag->t_flags = cpu_to_be16(tag_flag);
     679                 :       7224 :                 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
     680                 :            :                                         commit_transaction->t_tid);
     681                 :       7224 :                 tagp += tag_bytes;
     682                 :       7224 :                 space_left -= tag_bytes;
     683                 :       7224 :                 bufs++;
     684                 :            : 
     685         [ +  + ]:       7224 :                 if (first_tag) {
     686                 :        559 :                         memcpy (tagp, journal->j_uuid, 16);
     687                 :        559 :                         tagp += 16;
     688                 :        559 :                         space_left -= 16;
     689                 :        559 :                         first_tag = 0;
     690                 :            :                 }
     691                 :            : 
     692                 :            :                 /* If there's no more to do, or if the descriptor is full,
     693                 :            :                    let the IO rip! */
     694                 :            : 
     695         [ +  - ]:       7224 :                 if (bufs == journal->j_wbufsize ||
     696         [ +  + ]:       7224 :                     commit_transaction->t_buffers == NULL ||
     697         [ -  + ]:       6665 :                     space_left < tag_bytes + 16 + csum_size) {
     698                 :            : 
     699                 :        559 :                         jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
     700                 :            : 
     701                 :            :                         /* Write an end-of-descriptor marker before
     702                 :            :                            submitting the IOs.  "tag" still points to
     703                 :            :                            the last tag we set up. */
     704                 :            : 
     705                 :        559 :                         tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
     706                 :        559 : start_journal_io:
     707         [ +  - ]:        559 :                         if (descriptor)
     708                 :        559 :                                 jbd2_descriptor_block_csum_set(journal,
     709                 :            :                                                         descriptor);
     710                 :            : 
     711         [ +  + ]:       8342 :                         for (i = 0; i < bufs; i++) {
     712                 :       7783 :                                 struct buffer_head *bh = wbuf[i];
     713                 :            :                                 /*
     714                 :            :                                  * Compute checksum.
     715                 :            :                                  */
     716   [ +  -  -  + ]:      15566 :                                 if (jbd2_has_feature_checksum(journal)) {
     717                 :          0 :                                         crc32_sum =
     718                 :          0 :                                             jbd2_checksum_data(crc32_sum, bh);
     719                 :            :                                 }
     720                 :            : 
     721                 :       7783 :                                 lock_buffer(bh);
     722                 :       7783 :                                 clear_buffer_dirty(bh);
     723                 :       7783 :                                 set_buffer_uptodate(bh);
     724                 :       7783 :                                 bh->b_end_io = journal_end_buffer_io_sync;
     725                 :       7783 :                                 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
     726                 :            :                         }
     727                 :        559 :                         cond_resched();
     728                 :            : 
     729                 :            :                         /* Force a new descriptor to be generated next
     730                 :            :                            time round the loop. */
     731                 :        559 :                         descriptor = NULL;
     732                 :        559 :                         bufs = 0;
     733                 :            :                 }
     734                 :            :         }
     735                 :            : 
     736                 :        559 :         err = journal_finish_inode_data_buffers(journal, commit_transaction);
     737         [ -  + ]:        559 :         if (err) {
     738                 :          0 :                 printk(KERN_WARNING
     739                 :            :                         "JBD2: Detected IO errors while flushing file data "
     740                 :          0 :                        "on %s\n", journal->j_devname);
     741         [ #  # ]:          0 :                 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
     742                 :          0 :                         jbd2_journal_abort(journal, err);
     743                 :            :                 err = 0;
     744                 :            :         }
     745                 :            : 
     746                 :            :         /*
     747                 :            :          * Get current oldest transaction in the log before we issue flush
     748                 :            :          * to the filesystem device. After the flush we can be sure that
     749                 :            :          * blocks of all older transactions are checkpointed to persistent
     750                 :            :          * storage and we will be safe to update journal start in the
     751                 :            :          * superblock with the numbers we get here.
     752                 :            :          */
     753                 :        559 :         update_tail =
     754                 :        559 :                 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
     755                 :            : 
     756                 :        559 :         write_lock(&journal->j_state_lock);
     757         [ -  + ]:        559 :         if (update_tail) {
     758                 :          0 :                 long freed = first_block - journal->j_tail;
     759                 :            : 
     760         [ #  # ]:          0 :                 if (first_block < journal->j_tail)
     761                 :          0 :                         freed += journal->j_last - journal->j_first;
     762                 :            :                 /* Update tail only if we free significant amount of space */
     763         [ #  # ]:          0 :                 if (freed < journal->j_maxlen / 4)
     764                 :          0 :                         update_tail = 0;
     765                 :            :         }
     766         [ -  + ]:        559 :         J_ASSERT(commit_transaction->t_state == T_COMMIT);
     767                 :        559 :         commit_transaction->t_state = T_COMMIT_DFLUSH;
     768                 :        559 :         write_unlock(&journal->j_state_lock);
     769                 :            : 
     770                 :            :         /* 
     771                 :            :          * If the journal is not located on the file system device,
     772                 :            :          * then we must flush the file system device before we issue
     773                 :            :          * the commit record
     774                 :            :          */
     775         [ -  + ]:        559 :         if (commit_transaction->t_need_data_flush &&
     776         [ #  # ]:          0 :             (journal->j_fs_dev != journal->j_dev) &&
     777         [ #  # ]:          0 :             (journal->j_flags & JBD2_BARRIER))
     778                 :          0 :                 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
     779                 :            : 
     780                 :            :         /* Done it all: now write the commit record asynchronously. */
     781   [ +  -  -  + ]:       1118 :         if (jbd2_has_feature_async_commit(journal)) {
     782                 :          0 :                 err = journal_submit_commit_record(journal, commit_transaction,
     783                 :            :                                                  &cbh, crc32_sum);
     784         [ #  # ]:          0 :                 if (err)
     785                 :          0 :                         jbd2_journal_abort(journal, err);
     786                 :            :         }
     787                 :            : 
     788                 :        559 :         blk_finish_plug(&plug);
     789                 :            : 
     790                 :            :         /* Lo and behold: we have just managed to send a transaction to
     791                 :            :            the log.  Before we can commit it, wait for the IO so far to
     792                 :            :            complete.  Control buffers being written are on the
     793                 :            :            transaction's t_log_list queue, and metadata buffers are on
     794                 :            :            the io_bufs list.
     795                 :            : 
     796                 :            :            Wait for the buffers in reverse order.  That way we are
     797                 :            :            less likely to be woken up until all IOs have completed, and
     798                 :            :            so we incur less scheduling load.
     799                 :            :         */
     800                 :            : 
     801                 :        559 :         jbd_debug(3, "JBD2: commit phase 3\n");
     802                 :            : 
     803         [ +  + ]:       7783 :         while (!list_empty(&io_bufs)) {
     804                 :       7224 :                 struct buffer_head *bh = list_entry(io_bufs.prev,
     805                 :            :                                                     struct buffer_head,
     806                 :            :                                                     b_assoc_buffers);
     807                 :            : 
     808                 :       7224 :                 wait_on_buffer(bh);
     809                 :       7224 :                 cond_resched();
     810                 :            : 
     811         [ -  + ]:       7224 :                 if (unlikely(!buffer_uptodate(bh)))
     812                 :          0 :                         err = -EIO;
     813                 :       7224 :                 jbd2_unfile_log_bh(bh);
     814                 :       7224 :                 stats.run.rs_blocks_logged++;
     815                 :            : 
     816                 :            :                 /*
     817                 :            :                  * The list contains temporary buffer heads created by
     818                 :            :                  * jbd2_journal_write_metadata_buffer().
     819                 :            :                  */
     820                 :       7224 :                 BUFFER_TRACE(bh, "dumping temporary bh");
     821                 :       7224 :                 __brelse(bh);
     822         [ -  + ]:       7224 :                 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
     823                 :       7224 :                 free_buffer_head(bh);
     824                 :            : 
     825                 :            :                 /* We also have to refile the corresponding shadowed buffer */
     826                 :       7224 :                 jh = commit_transaction->t_shadow_list->b_tprev;
     827                 :       7224 :                 bh = jh2bh(jh);
     828                 :       7224 :                 clear_buffer_jwrite(bh);
     829         [ -  + ]:       7224 :                 J_ASSERT_BH(bh, buffer_jbddirty(bh));
     830         [ -  + ]:       7224 :                 J_ASSERT_BH(bh, !buffer_shadow(bh));
     831                 :            : 
     832                 :            :                 /* The metadata is now released for reuse, but we need
     833                 :            :                    to remember it against this transaction so that when
     834                 :            :                    we finally commit, we can do any checkpointing
     835                 :            :                    required. */
     836                 :       7224 :                 JBUFFER_TRACE(jh, "file as BJ_Forget");
     837                 :       7224 :                 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
     838                 :       7224 :                 JBUFFER_TRACE(jh, "brelse shadowed buffer");
     839                 :       7224 :                 __brelse(bh);
     840                 :            :         }
     841                 :            : 
     842         [ -  + ]:        559 :         J_ASSERT (commit_transaction->t_shadow_list == NULL);
     843                 :            : 
     844                 :            :         jbd_debug(3, "JBD2: commit phase 4\n");
     845                 :            : 
     846                 :            :         /* Here we wait for the revoke record and descriptor record buffers */
     847         [ +  + ]:       1123 :         while (!list_empty(&log_bufs)) {
     848                 :        564 :                 struct buffer_head *bh;
     849                 :            : 
     850                 :        564 :                 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
     851                 :        564 :                 wait_on_buffer(bh);
     852                 :        564 :                 cond_resched();
     853                 :            : 
     854         [ -  + ]:        564 :                 if (unlikely(!buffer_uptodate(bh)))
     855                 :          0 :                         err = -EIO;
     856                 :            : 
     857                 :        564 :                 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
     858                 :        564 :                 clear_buffer_jwrite(bh);
     859                 :        564 :                 jbd2_unfile_log_bh(bh);
     860                 :        564 :                 stats.run.rs_blocks_logged++;
     861                 :        564 :                 __brelse(bh);           /* One for getblk */
     862                 :            :                 /* AKPM: bforget here */
     863                 :            :         }
     864                 :            : 
     865         [ -  + ]:        559 :         if (err)
     866                 :          0 :                 jbd2_journal_abort(journal, err);
     867                 :            : 
     868                 :        559 :         jbd_debug(3, "JBD2: commit phase 5\n");
     869                 :        559 :         write_lock(&journal->j_state_lock);
     870         [ -  + ]:        559 :         J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
     871                 :        559 :         commit_transaction->t_state = T_COMMIT_JFLUSH;
     872                 :        559 :         write_unlock(&journal->j_state_lock);
     873                 :            : 
     874   [ +  -  +  - ]:       1118 :         if (!jbd2_has_feature_async_commit(journal)) {
     875                 :        559 :                 err = journal_submit_commit_record(journal, commit_transaction,
     876                 :            :                                                 &cbh, crc32_sum);
     877         [ -  + ]:        559 :                 if (err)
     878                 :          0 :                         jbd2_journal_abort(journal, err);
     879                 :            :         }
     880         [ +  - ]:        559 :         if (cbh)
     881                 :        559 :                 err = journal_wait_on_commit_record(journal, cbh);
     882                 :        559 :         stats.run.rs_blocks_logged++;
     883   [ +  -  -  + ]:       1118 :         if (jbd2_has_feature_async_commit(journal) &&
     884         [ #  # ]:          0 :             journal->j_flags & JBD2_BARRIER) {
     885                 :          0 :                 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
     886                 :            :         }
     887                 :            : 
     888         [ -  + ]:        559 :         if (err)
     889                 :          0 :                 jbd2_journal_abort(journal, err);
     890                 :            : 
     891         [ -  + ]:        559 :         WARN_ON_ONCE(
     892                 :            :                 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
     893                 :            : 
     894                 :            :         /*
     895                 :            :          * Now disk caches for filesystem device are flushed so we are safe to
     896                 :            :          * erase checkpointed transactions from the log by updating journal
     897                 :            :          * superblock.
     898                 :            :          */
     899         [ -  + ]:        559 :         if (update_tail)
     900                 :          0 :                 jbd2_update_log_tail(journal, first_tid, first_block);
     901                 :            : 
     902                 :            :         /* End of a transaction!  Finally, we can do checkpoint
     903                 :            :            processing: any buffers committed as a result of this
     904                 :            :            transaction can be removed from any checkpoint list it was on
     905                 :            :            before. */
     906                 :            : 
     907                 :        559 :         jbd_debug(3, "JBD2: commit phase 6\n");
     908                 :            : 
     909         [ -  + ]:        559 :         J_ASSERT(list_empty(&commit_transaction->t_inode_list));
     910         [ -  + ]:        559 :         J_ASSERT(commit_transaction->t_buffers == NULL);
     911         [ -  + ]:        559 :         J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
     912         [ -  + ]:        559 :         J_ASSERT(commit_transaction->t_shadow_list == NULL);
     913                 :            : 
     914                 :        559 : restart_loop:
     915                 :            :         /*
     916                 :            :          * As there are other places (journal_unmap_buffer()) adding buffers
     917                 :            :          * to this list we have to be careful and hold the j_list_lock.
     918                 :            :          */
     919                 :        559 :         spin_lock(&journal->j_list_lock);
     920         [ +  + ]:       7783 :         while (commit_transaction->t_forget) {
     921                 :       7224 :                 transaction_t *cp_transaction;
     922                 :       7224 :                 struct buffer_head *bh;
     923                 :       7224 :                 int try_to_free = 0;
     924                 :       7224 :                 bool drop_ref;
     925                 :            : 
     926                 :       7224 :                 jh = commit_transaction->t_forget;
     927                 :       7224 :                 spin_unlock(&journal->j_list_lock);
     928                 :       7224 :                 bh = jh2bh(jh);
     929                 :            :                 /*
     930                 :            :                  * Get a reference so that bh cannot be freed before we are
     931                 :            :                  * done with it.
     932                 :            :                  */
     933                 :       7224 :                 get_bh(bh);
     934                 :       7224 :                 spin_lock(&jh->b_state_lock);
     935         [ -  + ]:       7224 :                 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
     936                 :            : 
     937                 :            :                 /*
     938                 :            :                  * If there is undo-protected committed data against
     939                 :            :                  * this buffer, then we can remove it now.  If it is a
     940                 :            :                  * buffer needing such protection, the old frozen_data
     941                 :            :                  * field now points to a committed version of the
     942                 :            :                  * buffer, so rotate that field to the new committed
     943                 :            :                  * data.
     944                 :            :                  *
     945                 :            :                  * Otherwise, we can just throw away the frozen data now.
     946                 :            :                  *
     947                 :            :                  * We also know that the frozen data has already fired
     948                 :            :                  * its triggers if they exist, so we can clear that too.
     949                 :            :                  */
     950         [ -  + ]:       7224 :                 if (jh->b_committed_data) {
     951                 :          0 :                         jbd2_free(jh->b_committed_data, bh->b_size);
     952                 :          0 :                         jh->b_committed_data = NULL;
     953         [ #  # ]:          0 :                         if (jh->b_frozen_data) {
     954                 :          0 :                                 jh->b_committed_data = jh->b_frozen_data;
     955                 :          0 :                                 jh->b_frozen_data = NULL;
     956                 :          0 :                                 jh->b_frozen_triggers = NULL;
     957                 :            :                         }
     958         [ -  + ]:       7224 :                 } else if (jh->b_frozen_data) {
     959                 :          0 :                         jbd2_free(jh->b_frozen_data, bh->b_size);
     960                 :          0 :                         jh->b_frozen_data = NULL;
     961                 :          0 :                         jh->b_frozen_triggers = NULL;
     962                 :            :                 }
     963                 :            : 
     964                 :       7224 :                 spin_lock(&journal->j_list_lock);
     965                 :       7224 :                 cp_transaction = jh->b_cp_transaction;
     966         [ +  + ]:       7224 :                 if (cp_transaction) {
     967                 :       3710 :                         JBUFFER_TRACE(jh, "remove from old cp transaction");
     968                 :       3710 :                         cp_transaction->t_chp_stats.cs_dropped++;
     969                 :       3710 :                         __jbd2_journal_remove_checkpoint(jh);
     970                 :            :                 }
     971                 :            : 
     972                 :            :                 /* Only re-checkpoint the buffer_head if it is marked
     973                 :            :                  * dirty.  If the buffer was added to the BJ_Forget list
     974                 :            :                  * by jbd2_journal_forget, it may no longer be dirty and
     975                 :            :                  * there's no point in keeping a checkpoint record for
     976                 :            :                  * it. */
     977                 :            : 
     978                 :            :                 /*
     979                 :            :                  * A buffer which has been freed while still being journaled
     980                 :            :                  * by a previous transaction, refile the buffer to BJ_Forget of
     981                 :            :                  * the running transaction. If the just committed transaction
     982                 :            :                  * contains "add to orphan" operation, we can completely
     983                 :            :                  * invalidate the buffer now. We are rather through in that
     984                 :            :                  * since the buffer may be still accessible when blocksize <
     985                 :            :                  * pagesize and it is attached to the last partial page.
     986                 :            :                  */
     987   [ -  +  -  - ]:       7224 :                 if (buffer_freed(bh) && !jh->b_next_transaction) {
     988                 :          0 :                         struct address_space *mapping;
     989                 :            : 
     990                 :          0 :                         clear_buffer_freed(bh);
     991                 :          0 :                         clear_buffer_jbddirty(bh);
     992                 :            : 
     993                 :            :                         /*
     994                 :            :                          * Block device buffers need to stay mapped all the
     995                 :            :                          * time, so it is enough to clear buffer_jbddirty and
     996                 :            :                          * buffer_freed bits. For the file mapping buffers (i.e.
     997                 :            :                          * journalled data) we need to unmap buffer and clear
     998                 :            :                          * more bits. We also need to be careful about the check
     999                 :            :                          * because the data page mapping can get cleared under
    1000                 :            :                          * out hands, which alse need not to clear more bits
    1001                 :            :                          * because the page and buffers will be freed and can
    1002                 :            :                          * never be reused once we are done with them.
    1003                 :            :                          */
    1004         [ #  # ]:          0 :                         mapping = READ_ONCE(bh->b_page->mapping);
    1005   [ #  #  #  # ]:          0 :                         if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
    1006                 :          0 :                                 clear_buffer_mapped(bh);
    1007                 :          0 :                                 clear_buffer_new(bh);
    1008                 :          0 :                                 clear_buffer_req(bh);
    1009                 :          0 :                                 bh->b_bdev = NULL;
    1010                 :            :                         }
    1011                 :            :                 }
    1012                 :            : 
    1013         [ +  - ]:       7224 :                 if (buffer_jbddirty(bh)) {
    1014                 :       7224 :                         JBUFFER_TRACE(jh, "add to new checkpointing trans");
    1015                 :       7224 :                         __jbd2_journal_insert_checkpoint(jh, commit_transaction);
    1016         [ -  + ]:       7224 :                         if (is_journal_aborted(journal))
    1017                 :          0 :                                 clear_buffer_jbddirty(bh);
    1018                 :            :                 } else {
    1019         [ #  # ]:          0 :                         J_ASSERT_BH(bh, !buffer_dirty(bh));
    1020                 :            :                         /*
    1021                 :            :                          * The buffer on BJ_Forget list and not jbddirty means
    1022                 :            :                          * it has been freed by this transaction and hence it
    1023                 :            :                          * could not have been reallocated until this
    1024                 :            :                          * transaction has committed. *BUT* it could be
    1025                 :            :                          * reallocated once we have written all the data to
    1026                 :            :                          * disk and before we process the buffer on BJ_Forget
    1027                 :            :                          * list.
    1028                 :            :                          */
    1029         [ #  # ]:          0 :                         if (!jh->b_next_transaction)
    1030                 :          0 :                                 try_to_free = 1;
    1031                 :            :                 }
    1032                 :       7224 :                 JBUFFER_TRACE(jh, "refile or unfile buffer");
    1033                 :       7224 :                 drop_ref = __jbd2_journal_refile_buffer(jh);
    1034                 :       7224 :                 spin_unlock(&jh->b_state_lock);
    1035         [ +  + ]:       7224 :                 if (drop_ref)
    1036                 :       7217 :                         jbd2_journal_put_journal_head(jh);
    1037         [ -  + ]:       7224 :                 if (try_to_free)
    1038                 :          0 :                         release_buffer_page(bh);        /* Drops bh reference */
    1039                 :            :                 else
    1040                 :       7224 :                         __brelse(bh);
    1041                 :       7224 :                 cond_resched_lock(&journal->j_list_lock);
    1042                 :            :         }
    1043                 :        559 :         spin_unlock(&journal->j_list_lock);
    1044                 :            :         /*
    1045                 :            :          * This is a bit sleazy.  We use j_list_lock to protect transition
    1046                 :            :          * of a transaction into T_FINISHED state and calling
    1047                 :            :          * __jbd2_journal_drop_transaction(). Otherwise we could race with
    1048                 :            :          * other checkpointing code processing the transaction...
    1049                 :            :          */
    1050                 :        559 :         write_lock(&journal->j_state_lock);
    1051                 :        559 :         spin_lock(&journal->j_list_lock);
    1052                 :            :         /*
    1053                 :            :          * Now recheck if some buffers did not get attached to the transaction
    1054                 :            :          * while the lock was dropped...
    1055                 :            :          */
    1056         [ -  + ]:        559 :         if (commit_transaction->t_forget) {
    1057                 :          0 :                 spin_unlock(&journal->j_list_lock);
    1058                 :          0 :                 write_unlock(&journal->j_state_lock);
    1059                 :          0 :                 goto restart_loop;
    1060                 :            :         }
    1061                 :            : 
    1062                 :            :         /* Add the transaction to the checkpoint list
    1063                 :            :          * __journal_remove_checkpoint() can not destroy transaction
    1064                 :            :          * under us because it is not marked as T_FINISHED yet */
    1065         [ +  + ]:        559 :         if (journal->j_checkpoint_transactions == NULL) {
    1066                 :         78 :                 journal->j_checkpoint_transactions = commit_transaction;
    1067                 :         78 :                 commit_transaction->t_cpnext = commit_transaction;
    1068                 :         78 :                 commit_transaction->t_cpprev = commit_transaction;
    1069                 :            :         } else {
    1070                 :        481 :                 commit_transaction->t_cpnext =
    1071                 :            :                         journal->j_checkpoint_transactions;
    1072                 :        481 :                 commit_transaction->t_cpprev =
    1073                 :        481 :                         commit_transaction->t_cpnext->t_cpprev;
    1074                 :        481 :                 commit_transaction->t_cpnext->t_cpprev =
    1075                 :            :                         commit_transaction;
    1076                 :        481 :                 commit_transaction->t_cpprev->t_cpnext =
    1077                 :            :                                 commit_transaction;
    1078                 :            :         }
    1079                 :        559 :         spin_unlock(&journal->j_list_lock);
    1080                 :            : 
    1081                 :            :         /* Done with this transaction! */
    1082                 :            : 
    1083                 :        559 :         jbd_debug(3, "JBD2: commit phase 7\n");
    1084                 :            : 
    1085         [ -  + ]:        559 :         J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
    1086                 :            : 
    1087                 :        559 :         commit_transaction->t_start = jiffies;
    1088         [ +  - ]:        559 :         stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
    1089                 :            :                                               commit_transaction->t_start);
    1090                 :            : 
    1091                 :            :         /*
    1092                 :            :          * File the transaction statistics
    1093                 :            :          */
    1094                 :        559 :         stats.ts_tid = commit_transaction->t_tid;
    1095                 :       1118 :         stats.run.rs_handle_count =
    1096                 :        559 :                 atomic_read(&commit_transaction->t_handle_count);
    1097                 :        559 :         trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
    1098                 :        559 :                              commit_transaction->t_tid, &stats.run);
    1099                 :        559 :         stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
    1100                 :            : 
    1101                 :        559 :         commit_transaction->t_state = T_COMMIT_CALLBACK;
    1102         [ -  + ]:        559 :         J_ASSERT(commit_transaction == journal->j_committing_transaction);
    1103                 :        559 :         journal->j_commit_sequence = commit_transaction->t_tid;
    1104                 :        559 :         journal->j_committing_transaction = NULL;
    1105         [ +  + ]:        559 :         commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
    1106                 :            : 
    1107                 :            :         /*
    1108                 :            :          * weight the commit time higher than the average time so we don't
    1109                 :            :          * react too strongly to vast changes in the commit time
    1110                 :            :          */
    1111         [ +  + ]:        559 :         if (likely(journal->j_average_commit_time))
    1112                 :        481 :                 journal->j_average_commit_time = (commit_time +
    1113                 :        481 :                                 journal->j_average_commit_time*3) / 4;
    1114                 :            :         else
    1115                 :         78 :                 journal->j_average_commit_time = commit_time;
    1116                 :            : 
    1117                 :        559 :         write_unlock(&journal->j_state_lock);
    1118                 :            : 
    1119         [ +  - ]:        559 :         if (journal->j_commit_callback)
    1120                 :        559 :                 journal->j_commit_callback(journal, commit_transaction);
    1121                 :            : 
    1122                 :        559 :         trace_jbd2_end_commit(journal, commit_transaction);
    1123                 :            :         jbd_debug(1, "JBD2: commit %d complete, head %d\n",
    1124                 :        559 :                   journal->j_commit_sequence, journal->j_tail_sequence);
    1125                 :            : 
    1126                 :        559 :         write_lock(&journal->j_state_lock);
    1127                 :        559 :         spin_lock(&journal->j_list_lock);
    1128                 :        559 :         commit_transaction->t_state = T_FINISHED;
    1129                 :            :         /* Check if the transaction can be dropped now that we are finished */
    1130         [ -  + ]:        559 :         if (commit_transaction->t_checkpoint_list == NULL &&
    1131         [ #  # ]:          0 :             commit_transaction->t_checkpoint_io_list == NULL) {
    1132                 :          0 :                 __jbd2_journal_drop_transaction(journal, commit_transaction);
    1133                 :          0 :                 jbd2_journal_free_transaction(commit_transaction);
    1134                 :            :         }
    1135                 :        559 :         spin_unlock(&journal->j_list_lock);
    1136                 :        559 :         write_unlock(&journal->j_state_lock);
    1137                 :        559 :         wake_up(&journal->j_wait_done_commit);
    1138                 :            : 
    1139                 :            :         /*
    1140                 :            :          * Calculate overall stats
    1141                 :            :          */
    1142                 :        559 :         spin_lock(&journal->j_history_lock);
    1143                 :        559 :         journal->j_stats.ts_tid++;
    1144                 :        559 :         journal->j_stats.ts_requested += stats.ts_requested;
    1145                 :        559 :         journal->j_stats.run.rs_wait += stats.run.rs_wait;
    1146                 :        559 :         journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
    1147                 :        559 :         journal->j_stats.run.rs_running += stats.run.rs_running;
    1148                 :        559 :         journal->j_stats.run.rs_locked += stats.run.rs_locked;
    1149                 :        559 :         journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
    1150                 :        559 :         journal->j_stats.run.rs_logging += stats.run.rs_logging;
    1151                 :        559 :         journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
    1152                 :        559 :         journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
    1153                 :        559 :         journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
    1154                 :        559 :         spin_unlock(&journal->j_history_lock);
    1155                 :        559 : }

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