[PATCH RESEND 1/2] btrfs: fix parent in memory total_devices after seed delete

[Anand Jain <anand.jain@oracle.com>]

In case of deleting the seed device the %cur_devices (seed)
and the %fs_devices (parent) are different. Now, as the parent
fs_devices::total_devices also maintains the total number of devices
including the seed device, so decrement its in-memory value for the
successful seed delete. We are already updating its corresponding on-disk
btrfs_super_block::number_devices value.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 fs/btrfs/volumes.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 5bd6f3a40f9c..6b807b166ca3 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2027,6 +2027,9 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path,
 
 	cur_devices->num_devices--;
 	cur_devices->total_devices--;
+	/* Update total_devices for the parent fs_devices if its seed */
+	if (cur_devices != fs_devices)
+		fs_devices->total_devices--;
 
 	if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
 		cur_devices->missing_devices--;
-- 
2.15.0