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authorChris Mason <chris.mason@oracle.com>2011-12-23 07:53:00 -0500
committerChris Mason <chris.mason@oracle.com>2011-12-23 07:53:00 -0500
commit8d532b2afb2eacc84588db709ec280a3d1219be3 (patch)
tree27a4353e75d67bc41e9d2172702dbed1109095eb
parentd85c8a6f1bc083279215ff6e79b7c292bf3ec905 (diff)
downloadlinux-8d532b2afb2eacc84588db709ec280a3d1219be3.tar.gz
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>
-rw-r--r--fs/btrfs/async-thread.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index cb97174e2366..0b394580d860 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -563,8 +563,8 @@ static struct btrfs_worker_thread *find_worker(struct btrfs_workers *workers)
 	struct list_head *fallback;
 	int ret;
 
-again:
 	spin_lock_irqsave(&workers->lock, flags);
+again:
 	worker = next_worker(workers);
 
 	if (!worker) {
@@ -579,6 +579,7 @@ again:
 			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;