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authorZhihao Cheng <chengzhihao1@huawei.com>2023-07-14 10:55:27 +0800
committerTheodore Ts'o <tytso@mit.edu>2023-08-04 16:32:23 -0400
commit590a809ff743e7bd890ba5fb36bc38e20a36de53 (patch)
tree694f41cda03b2cb8878e11397ca7c29b6b0ea743 /fs/jbd2
parent373ac521799d9e97061515aca6ec6621789036bb (diff)
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')
-rw-r--r--fs/jbd2/checkpoint.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 936c6d758a65..f033ac807013 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)) {