[PATCH 2/2] btrfs: zoned: fix zone finishing with missing devices

[Johannes Thumshirn <jth@kernel.org>]

From: Johannes Thumshirn <johannes.thumshirn@wdc.com>

If do_zone_finish() is called with a filesystem that has missing devices
(e.g. a RAID file system mounted in degraded mode) it is accessing the
btrfs_device::zone_info pointer, which will not be set if the device
in question is missing.

Check if the device is present (by checking if it has a valid block device
pointer associated) and if not, skip zone finishing for it.

Fixes: 4dcbb8ab31c1 ("btrfs: zoned: make zone finishing multi stripe capable")
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/zoned.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 8924f58919e8..7c502192cd6b 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -2274,6 +2274,9 @@ static int do_zone_finish(struct btrfs_block_group *block_group, bool fully_writ
 		struct btrfs_zoned_device_info *zinfo = device->zone_info;
 		unsigned int nofs_flags;
 
+		if (!device->bdev)
+			continue;
+
 		if (zinfo->max_active_zones == 0)
 			continue;
 
-- 
2.43.0