Btrfs: fix worker lock misuse in find_worker
Dan Carpenter noticed that we were doing a double unlock on the worker
lock, and sometimes picking a worker thread without the lock held.
This fixes both errors.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index cb97174..0b39458 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -563,8 +563,8 @@
struct list_head *fallback;
int ret;
-again:
spin_lock_irqsave(&workers->lock, flags);
+again:
worker = next_worker(workers);
if (!worker) {
@@ -579,6 +579,7 @@
spin_unlock_irqrestore(&workers->lock, flags);
/* we're below the limit, start another worker */
ret = __btrfs_start_workers(workers);
+ spin_lock_irqsave(&workers->lock, flags);
if (ret)
goto fallback;
goto again;