blockdev: drain while unlocked in external_snapshot_action()

This is in preparation to mark bdrv_drained_begin() as GRAPH_UNLOCKED.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Message-ID: <20250530151125.955508-19-f.ebner@proxmox.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
1 file changed