diff mbox series

[5.10,265/299] ext4: annotate data race in jbd2_journal_dirty_metadata()

Message ID 20210510102013.696784393@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH May 10, 2021, 10:21 a.m. UTC 
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(-)
diff mbox series

Patch

--- 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)