Commit a39a24fb authored Oct 26, 2015 by Alberto Garcia Committed by Kevin Wolf Nov 11, 2015

block: check for existing device IDs in external_snapshot_prepare()



The 'snapshot-node-name' parameter of blockdev-snapshot-sync allows
setting the node name of the image that is going to be created.

Before creating the image, external_snapshot_prepare() checks that the
name is not already being used. The check is however incomplete since
it only considers existing node names, but node names must not clash
with device IDs either because they share the same namespace.

If the user attempts to create a snapshot using the name of an
existing device for the 'snapshot-node-name' parameter the operation
will eventually fail, but only after the new image has been created.

This patch replaces bdrv_find_node() with bdrv_lookup_bs() to extend
the check to existing device IDs, and thus detect possible name
clashes before the new image is created.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

parent adfe2030

blockdev.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -1579,8 +1579,9 @@ static void external_snapshot_prepare(BlkTransactionState *common,
		return;
		}

		if (has_snapshot_node_name && bdrv_find_node(snapshot_node_name)) {
		error_setg(errp, "New snapshot node name already existing");
		if (has_snapshot_node_name &&
		bdrv_lookup_bs(snapshot_node_name, snapshot_node_name, NULL)) {
		error_setg(errp, "New snapshot node name already in use");
		return;
		}