[PATCH 4.20 092/145] btrfs: dev-replace: go back to suspended state if target device is missing

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Anand Jain <anand.jain@xxxxxxxxxx>

commit 0d228ece59a35a9b9e8ff0d40653234a6d90f61e upstream.

At the time of forced unmount we place the running replace to
BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED state, so when the system comes
back and expect the target device is missing.

Then let the replace state continue to be in
BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED state instead of
BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED as there isn't any matching scrub
running as part of replace.

Fixes: e93c89c1aaaa ("Btrfs: add new sources for device replace code")
CC: stable@xxxxxxxxxxxxxxx # 4.4+
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/btrfs/dev-replace.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -884,6 +884,8 @@ int btrfs_resume_dev_replace_async(struc
 			   "cannot continue dev_replace, tgtdev is missing");
 		btrfs_info(fs_info,
 			   "you may cancel the operation after 'mount -o degraded'");
+		dev_replace->replace_state =
+					BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
 		btrfs_dev_replace_write_unlock(dev_replace);
 		return 0;
 	}