From: Chris Mason <chris.mason@oracle.com>
Date: Fri, 23 Dec 2011 12:53:00 +0000 (-0500)
Subject: Btrfs: fix worker lock misuse in find_worker
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=8d532b2afb2eacc84588db709ec280a3d1219be3;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

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 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;