Btrfs: properly wait log writers during log sync
A recently fsync optimization make btrfs_sync_log skip calling
wait_for_writer in the single log writer case. This is incorrect
since the writer count can also be increased by btrfs_pin_log.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 4aff766..f51bf13 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -1995,12 +1995,13 @@
if (atomic_read(&root->log_commit[(index1 + 1) % 2]))
wait_log_commit(trans, root, root->log_transid - 1);
- while (root->log_multiple_pids) {
+ while (1) {
unsigned long batch = root->log_batch;
- mutex_unlock(&root->log_mutex);
- schedule_timeout_uninterruptible(1);
- mutex_lock(&root->log_mutex);
-
+ if (root->log_multiple_pids) {
+ mutex_unlock(&root->log_mutex);
+ schedule_timeout_uninterruptible(1);
+ mutex_lock(&root->log_mutex);
+ }
wait_for_writer(trans, root);
if (batch == root->log_batch)
break;