[PATCH 5.9 207/255] jbd2: fix up sparse warnings in checkpoint code

Greg Kroah-Hartman
2020-11-17T13:40:28Z

From: Theodore Ts'o <tytso@mit.edu>

commit 05d5233df85e9621597c5838e95235107eb624a2 upstream.

Add missing __acquires() and __releases() annotations. Also, in an
"this should never happen" WARN_ON check, if it *does* actually
happen, we need to release j_state_lock since this function is always
supposed to release that lock. Otherwise, things will quickly grind
to a halt after the WARN_ON trips.

Fixes: 96f1e0974575 ("jbd2: avoid long hold times of j_state_lock...")
Cc: stable@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/jbd2/checkpoint.c | 2 ++
fs/jbd2/transaction.c | 4 +++-
2 files changed, 5 insertions(+), 1 deletion(-)

--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -106,6 +106,8 @@ static int __try_to_free_cp_buf(struct j
* for a checkpoint to free up some space in the log.
*/
void __jbd2_log_wait_for_space(journal_t *journal)
+__acquires(&journal->j_state_lock)
+__releases(&journal->j_state_lock)
{
int nblocks, space_left;
/* assert_spin_locked(&journal->j_state_lock); */
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -195,8 +195,10 @@ static void wait_transaction_switching(j
DEFINE_WAIT(wait);

if (WARN_ON(!journal->j_running_transaction ||
- journal->j_running_transaction->t_state != T_SWITCH))
+ journal->j_running_transaction->t_state != T_SWITCH)) {
+ read_unlock(&journal->j_state_lock);
return;
+ }
prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
TASK_UNINTERRUPTIBLE);
read_unlock(&journal->j_state_lock);