From: Jan Kara jack@suse.cz
commit 83fe6b18b8d04c6c849379005e1679bac9752466 upstream.
Assertion checks in jbd2_journal_dirty_metadata() are known to be racy but we don't want to be grabbing locks just for them. We thus recheck them under b_state_lock only if it looks like they would fail. Annotate the checks with data_race().
Cc: stable@kernel.org Reported-by: Hao Sun sunhao.th@gmail.com Signed-off-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20210406161804.20150-2-jack@suse.cz Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/jbd2/transaction.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -1479,8 +1479,8 @@ int jbd2_journal_dirty_metadata(handle_t * crucial to catch bugs so let's do a reliable check until the * lockless handling is fully proven. */ - if (jh->b_transaction != transaction && - jh->b_next_transaction != transaction) { + if (data_race(jh->b_transaction != transaction && + jh->b_next_transaction != transaction)) { spin_lock(&jh->b_state_lock); J_ASSERT_JH(jh, jh->b_transaction == transaction || jh->b_next_transaction == transaction); @@ -1488,8 +1488,8 @@ int jbd2_journal_dirty_metadata(handle_t } if (jh->b_modified == 1) { /* If it's in our transaction it must be in BJ_Metadata list. */ - if (jh->b_transaction == transaction && - jh->b_jlist != BJ_Metadata) { + if (data_race(jh->b_transaction == transaction && + jh->b_jlist != BJ_Metadata)) { spin_lock(&jh->b_state_lock); if (jh->b_transaction == transaction && jh->b_jlist != BJ_Metadata)