Btrfs: just wait or commit our own log sub-transaction
We might commit the log sub-transaction which didn't contain the metadata we
logged. It was because we didn't record the log transid and just select
the current log sub-transaction to commit, but the right one might be
committed by the other task already. Actually, we needn't do anything
and it is safe that we go back directly in this case.
This patch improves the log sync by the above idea. We record the transid
of the log sub-transaction in which we log the metadata, and the transid
of the log sub-transaction we have committed. If the committed transid
is >= the transid we record when logging the metadata, we just go back.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9064107..b2c0336 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1723,6 +1723,9 @@
atomic_t log_commit[2];
atomic_t log_batch;
int log_transid;
+ /* No matter the commit succeeds or not*/
+ int log_transid_committed;
+ /* Just be updated when the commit succeeds. */
int last_log_commit;
pid_t log_start_pid;
bool log_multiple_pids;