[PATCH 2/4] btrfs: mark device addition as sb_writing

Naohiro Aota
2022-03-11T07:38:50Z

btrfs_init_new_device() calls btrfs_relocate_sys_chunk() which incurs
file-system internal writing. That writing can cause a deadlock with
FS freezing like as described in like as described in commit
26559780b953 ("btrfs: zoned: mark relocation as writing").

Mark the device addition as sb_writing. This is also consistent with
the removing device ioctl counterpart.

Fixes: 5accdf82ba25 ("fs: Improve filesystem freezing handling")
Cc: stable@vger.kernel.org
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
fs/btrfs/ioctl.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 238cee5b5254..ffa30fd3eed2 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3484,6 +3484,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
return -EINVAL;
}

+ sb_start_write(fs_info->sb);
if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_ADD)) {
if (!btrfs_exclop_start_try_lock(fs_info, BTRFS_EXCLOP_DEV_ADD))
return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
@@ -3516,6 +3517,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE_PAUSED);
else
btrfs_exclop_finish(fs_info);
+ sb_end_write(fs_info->sb);
return ret;
}

--
2.35.1