[PATCH 1/2] btrfs: zoned: fix zone activation with missing devices

[Johannes Thumshirn <jth@kernel.org>]

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

If btrfs_zone_activate() 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 activation for it.

Fixes: f9a912a3c45f ("btrfs: zoned: make zone activation 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 c21a97b32f9a..8924f58919e8 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -2110,6 +2110,9 @@ bool btrfs_zone_activate(struct btrfs_block_group *block_group)
 		physical = map->stripes[i].physical;
 		zinfo = device->zone_info;
 
+		if (!device->bdev)
+			continue;
+
 		if (zinfo->max_active_zones == 0)
 			continue;
 
-- 
2.43.0