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| author | Zhihao Cheng <chengzhihao1@huawei.com> | 2023-07-14 10:55:27 +0800 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2023-08-04 16:32:23 -0400 |
| commit | 590a809ff743e7bd890ba5fb36bc38e20a36de53 (patch) | |
| tree | 694f41cda03b2cb8878e11397ca7c29b6b0ea743 /fs/jbd2/checkpoint.c | |
| parent | 373ac521799d9e97061515aca6ec6621789036bb (diff) | |
| download | linux-590a809ff743e7bd890ba5fb36bc38e20a36de53.tar.gz | |
jbd2: check 'jh->b_transaction' before removing it from checkpoint
Following process will corrupt ext4 image:
Step 1:
jbd2_journal_commit_transaction
__jbd2_journal_insert_checkpoint(jh, commit_transaction)
// Put jh into trans1->t_checkpoint_list
journal->j_checkpoint_transactions = commit_transaction
// Put trans1 into journal->j_checkpoint_transactions
Step 2:
do_get_write_access
test_clear_buffer_dirty(bh) // clear buffer dirty，set jbd dirty
__jbd2_journal_file_buffer(jh, transaction) // jh belongs to trans2
Step 3:
drop_cache
journal_shrink_one_cp_list
jbd2_journal_try_remove_checkpoint
if (!trylock_buffer(bh)) // lock bh, true
if (buffer_dirty(bh)) // buffer is not dirty
__jbd2_journal_remove_checkpoint(jh)
// remove jh from trans1->t_checkpoint_list
Step 4:
jbd2_log_do_checkpoint
trans1 = journal->j_checkpoint_transactions
// jh is not in trans1->t_checkpoint_list
jbd2_cleanup_journal_tail(journal) // trans1 is done
Step 5: Power cut, trans2 is not committed, jh is lost in next mounting.
Fix it by checking 'jh->b_transaction' before remove it from checkpoint.
Cc: stable@kernel.org
Fixes: 46f881b5b175 ("jbd2: fix a race when checking checkpoint buffer busy")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230714025528.564988-3-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/jbd2/checkpoint.c')
| -rw-r--r-- | fs/jbd2/checkpoint.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c index 936c6d758a651..f033ac807013c 100644 --- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -639,6 +639,8 @@ int jbd2_journal_try_remove_checkpoint(struct journal_head *jh) { struct buffer_head *bh = jh2bh(jh); + if (jh->b_transaction) + return -EBUSY; if (!trylock_buffer(bh)) return -EBUSY; if (buffer_dirty(bh)) { |