We can hold j_state_lock for writing at the beginning of
jbd2_journal_commit_transaction() for a rather long time (reportedly for
30 ms) due cleaning revoke bits of all revoked buffers under it. The
handling of revoke tables as well as cleaning of t_reserved_list, and
checkpoint lists does not need j_state_lock for anything. Furthermore
the transaction is in T_LOCKED state and we waited for all outstanding
handles so nobody is going to be adding anything to the transaction.
Just drop the lock for unnecessary operations.
Reported-and-tested-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Suggested-by: "Theodore Y. Ts'o" <tytso@xxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/jbd2/commit.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 150cc030b4d7..356b75fa3101 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -422,6 +422,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
stats.run.rs_locked);
stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
stats.run.rs_locked);
+ write_unlock(&journal->j_state_lock);
spin_lock(&commit_transaction->t_handle_lock);
while (atomic_read(&commit_transaction->t_updates)) {
@@ -431,9 +432,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
TASK_UNINTERRUPTIBLE);
if (atomic_read(&commit_transaction->t_updates)) {
spin_unlock(&commit_transaction->t_handle_lock);
- write_unlock(&journal->j_state_lock);
schedule();
- write_lock(&journal->j_state_lock);
spin_lock(&commit_transaction->t_handle_lock);
}
finish_wait(&journal->j_wait_updates, &wait);
@@ -505,6 +504,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
atomic_sub(atomic_read(&journal->j_reserved_credits),
&commit_transaction->t_outstanding_credits);
+ write_lock(&journal->j_state_lock);
trace_jbd2_commit_flushing(journal, commit_transaction);
stats.run.rs_flushing = jiffies;
stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
--
2.16.4
