6.1-stable review patch. If anyone has any objections, please let me know.
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From: Zhihao Cheng chengzhihao1@huawei.com
commit 590a809ff743e7bd890ba5fb36bc38e20a36de53 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/jbd2/checkpoint.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -639,6 +639,8 @@ int jbd2_journal_try_remove_checkpoint(s { struct buffer_head *bh = jh2bh(jh);
+ if (jh->b_transaction) + return -EBUSY; if (!trylock_buffer(bh)) return -EBUSY; if (buffer_dirty(bh)) {