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ext4: annotate data race in jbd2_journal_dirty_metadata() 

commit 83fe6b18b8 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>
pull/331/head^2
Jan Kara 2021-04-06 18:18:00 +02:00 committed by Greg Kroah-Hartman
parent 9aca313726
commit 346190959f
1 changed files with 4 additions and 4 deletions
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8
fs/jbd2/transaction.c
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@ -1479,8 +1479,8 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
* 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 *handle, struct buffer_head *bh)
}
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)