[PATCH 5.12 337/384] ext4: annotate data race in jbd2_journal_dirty_metadata()
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-05-10 12:37:13
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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 <redacted> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20210406161804.20150-2-jack@suse.cz (local) 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)