From 3680b48533aec77fd21875c0c11398e1c2774f1e Mon Sep 17 00:00:00 2001 From: Naohiro Aota Date: Tue, 29 Mar 2022 15:55:58 +0900 Subject: [PATCH] btrfs: mark resumed async balance as writing commit a690e5f2db4d1dca742ce734aaff9f3112d63764 upstream. When btrfs balance is interrupted with umount, the background balance resumes on the next mount. There is a potential deadlock with FS freezing here like as described in commit 26559780b953 ("btrfs: zoned: mark relocation as writing"). Mark the process as sb_writing to avoid it. Reviewed-by: Filipe Manana CC: stable@vger.kernel.org # 4.9+ Signed-off-by: Naohiro Aota Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/volumes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index f6d6825..471cc47 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4389,10 +4389,12 @@ static int balance_kthread(void *data) struct btrfs_fs_info *fs_info = data; int ret = 0; + sb_start_write(fs_info->sb); mutex_lock(&fs_info->balance_mutex); if (fs_info->balance_ctl) ret = btrfs_balance(fs_info, fs_info->balance_ctl, NULL); mutex_unlock(&fs_info->balance_mutex); + sb_end_write(fs_info->sb); return ret; } -- 2.7.4