At Fri, 31 Aug 2012 15:23:01 +0800,
levin li wrote:
>
> OK, I got the point of CURRENT VDI, but there's another problem, I never
> thought of
> rolling back a snapshot to its parent or other, take think of this:
>
> snap1 is the root snapshot, then we start snap1 with QEMU and it creates
> another snapshot
> snap2 which creates its own object A, and A is not included in snap1, then
> user may clones
> a new VDI clone1 from snap2, it derives from snap2 together with object A,
> but now if we
> rollback snap2 to snap1 and the object A is lost, how can clone1 find this
> object, is it right?
The rollback operation shouldn't delete snap2.
Here is a draft patch which implements my example but doesn't support
resetting clone vdis. I hope it would help you.
==
commit 138511431d4f87642572b0e2a51d869240b5ac83
Author: MORITA Kazutaka <morita.kazut...@lab.ntt.co.jp>
Date: Fri Aug 31 17:21:38 2012 +0900
[tmp] collie: add vdi rollback support
Signed-off-by: MORITA Kazutaka <morita.kazut...@lab.ntt.co.jp>
diff --git a/collie/vdi.c b/collie/vdi.c
index 966fb9f..39e04a7 100644
--- a/collie/vdi.c
+++ b/collie/vdi.c
@@ -752,6 +752,37 @@ static int vdi_delete(int argc, char **argv)
return EXIT_SUCCESS;
}
+static int vdi_rollback(int argc, char **argv)
+{
+ char *vdiname = argv[optind++];
+ uint32_t base_vid;
+ int ret;
+ char buf[SD_INODE_HEADER_SIZE];
+ struct sheepdog_inode *inode = (struct sheepdog_inode *)buf;
+
+ if (!vdi_cmd_data.snapshot_id && !vdi_cmd_data.snapshot_tag[0]) {
+ fprintf(stderr, "Please specify the '-s' option\n");
+ return EXIT_USAGE;
+ }
+
+ ret = find_vdi_name(vdiname, vdi_cmd_data.snapshot_id,
+ vdi_cmd_data.snapshot_tag, &base_vid, 0);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to open VDI %s\n", vdiname);
+ return EXIT_FAILURE;
+ }
+
+ inode = xmalloc(sizeof(*inode));
+ ret = sd_read_object(vid_to_vdi_oid(base_vid), inode, SD_INODE_SIZE, 0);
+ if (ret != SD_RES_SUCCESS) {
+ fprintf(stderr, "Failed to read an inode\n");
+ return EXIT_FAILURE;
+ }
+
+ return do_vdi_create(vdiname, inode->vdi_size, base_vid, NULL,
+ inode->snap_id, vdi_cmd_data.nr_copies);
+}
+
static int vdi_object(int argc, char **argv)
{
char *vdiname = argv[optind];
@@ -1537,6 +1568,9 @@ static struct subcommand vdi_cmd[] = {
{"delete", "<vdiname>", "saph", "delete an image",
NULL, SUBCMD_FLAG_NEED_THIRD_ARG,
vdi_delete, vdi_options},
+ {"rollback", "<vdiname>", "saph", "rollback to a snapshot",
+ NULL, SUBCMD_FLAG_NEED_THIRD_ARG,
+ vdi_rollback, vdi_options},
{"list", "[vdiname]", "aprh", "list images",
NULL, 0, vdi_list, vdi_options},
{"tree", NULL, "aph", "show images in tree view format",
--
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