[PATCH 5.15 032/177] btrfs: update latest_dev when we create a sprout device

[Greg Kroah-Hartman]

From: Anand Jain <anand.jain@xxxxxxxxxx>

Commit b7cb29e666fe79dda5dbe5f57fb7c92413bf161c upstream.

When we add a device to the seed filesystem (sprouting) it is a new
filesystem (and fsid) on the device added. Update the latest_dev so
that /proc/self/mounts shows the correct device.

Example:

  $ btrfstune -S1 /dev/vg/seed
  $ mount /dev/vg/seed /btrfs
  mount: /btrfs: WARNING: device write-protected, mounted read-only.

  $ cat /proc/self/mounts | grep btrfs
  /dev/mapper/vg-seed /btrfs btrfs ro,relatime,space_cache,subvolid=5,subvol=/ 0 0

  $ btrfs dev add -f /dev/vg/new /btrfs

Before:

  $ cat /proc/self/mounts | grep btrfs
  /dev/mapper/vg-seed /btrfs btrfs ro,relatime,space_cache,subvolid=5,subvol=/ 0 0

After:

  $ cat /proc/self/mounts | grep btrfs
  /dev/mapper/vg-new /btrfs btrfs ro,relatime,space_cache,subvolid=5,subvol=/ 0 0

Tested-by: Su Yue <l@xxxxxxxxxx>
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/btrfs/volumes.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2634,6 +2634,8 @@ int btrfs_init_new_device(struct btrfs_f
 			btrfs_abort_transaction(trans, ret);
 			goto error_trans;
 		}
+		btrfs_assign_next_active_device(fs_info->fs_devices->latest_dev,
+						device);
 	}
 
 	device->fs_devices = fs_devices;