From 800ee2247f483b6d05ed47ef3bbc90b56451746c Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <slyfox@gentoo.org>
Date: Mon, 7 Apr 2014 10:55:46 +0300
Subject: [PATCH] btrfs: fix crash in remount(thread_pool=) case
Reproducer:
mount /dev/ubda /mnt
mount -oremount,thread_pool=42 /mnt
Gives a crash:
? btrfs_workqueue_set_max+0x0/0x70
btrfs_resize_thread_pool+0xe3/0xf0
? sync_filesystem+0x0/0xc0
? btrfs_resize_thread_pool+0x0/0xf0
btrfs_remount+0x1d2/0x570
? kern_path+0x0/0x80
do_remount_sb+0xd9/0x1c0
do_mount+0x26a/0xbf0
? kfree+0x0/0x1b0
SyS_mount+0xc4/0x110
It's a call
btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers, new_pool_size);
with
fs_info->scrub_wr_completion_workers = NULL;
as scrub wqs get created only on user's demand.
Patch skips not-created-yet workqueues.
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
CC: Qu Wenruo <quwenruo@cn.fujitsu.com>
CC: Chris Mason <clm@fb.com>
CC: Josef Bacik <jbacik@fb.com>
CC: linux-btrfs@vger.kernel.org
Signed-off-by: Chris Mason <clm@fb.com>
---
fs/btrfs/async-thread.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index ecb5832c0967..5a201d81049c 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -323,6 +323,8 @@ void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max)
{
+ if (!wq)
+ return;
wq->normal->max_active = max;
if (wq->high)
wq->high->max_active = max;