]> git.proxmox.com Git - mirror_qemu.git/commitdiff
blockdev: Snapshotting must not open second instance of old top
authorKevin Wolf <kwolf@redhat.com>
Wed, 2 Mar 2016 11:16:44 +0000 (12:16 +0100)
committerKevin Wolf <kwolf@redhat.com>
Mon, 14 Mar 2016 15:46:43 +0000 (16:46 +0100)
Calling bdrv_img_create() with a size of -1 means that it determines the
size automatically by opening the backing file. However, in the case of
live snapshots, the backing file is already opened and we must avoid
opening the same image twice at the same time. Apart from that, just
getting the size from the already existing BDS is a lot less overhead
than opening a new instance.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
blockdev.c

index 0f20c6511f47138e5d62bbeed259598844f20c83..e1c1540010965de945c9dac9f5ae6cc6815a64f2 100644 (file)
@@ -1732,10 +1732,15 @@ static void external_snapshot_prepare(BlkActionState *common,
         /* create new image w/backing file */
         mode = s->has_mode ? s->mode : NEW_IMAGE_MODE_ABSOLUTE_PATHS;
         if (mode != NEW_IMAGE_MODE_EXISTING) {
+            int64_t size = bdrv_getlength(state->old_bs);
+            if (size < 0) {
+                error_setg_errno(errp, -size, "bdrv_getlength failed");
+                return;
+            }
             bdrv_img_create(new_image_file, format,
                             state->old_bs->filename,
                             state->old_bs->drv->format_name,
-                            NULL, -1, flags, &local_err, false);
+                            NULL, size, flags, &local_err, false);
             if (local_err) {
                 error_propagate(errp, local_err);
                 return;