From: Naohiro Aota <naohiro.aota@wdc.com> stable inclusion from stable-v5.10.112 commit 5e4dd1799883941cd9590415a47d967909c8d2ac category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5HL0X Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- 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 <fdmanana@suse.com> CC: stable@vger.kernel.org # 4.9+ Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Acked-by: Xie XiuQi <xiexiuqi@huawei.com> --- fs/btrfs/volumes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index e462de991723..366d04763864 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4220,10 +4220,12 @@ 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; } -- 2.20.1