[Qemu-devel] [PATCH v4 3/8] block: don't make snapshots for filters

[Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>]

This patch disables snapshotting for block driver filters.
It is needed, because snapshots should be created
in underlying disk images, not in filters itself.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 block/snapshot.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/snapshot.c b/block/snapshot.c
index bf5c2ca..8998b8b 100644
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -184,6 +184,9 @@ int bdrv_snapshot_goto(BlockDriverState *bs,
     if (!drv) {
         return -ENOMEDIUM;
     }
+    if (drv->is_filter) {
+        return 0;
+    }
     if (drv->bdrv_snapshot_goto) {
         return drv->bdrv_snapshot_goto(bs, snapshot_id);
     }