On Thu, Mar 1, 2012 at 2:49 AM, Dong Xu Wang <wdon...@linux.vnet.ibm.com> wrote:
> From: Dong Xu Wang <wdon...@linux.vnet.ibm.com>
>
> We can not use raw to support snapshot_file, but add-cow can do this.
>
> CC: Marcelo Tosatti <mtosa...@redhat.com>
> CC: Kevin Wolf <kw...@redhat.com>
> CC: Stefan Hajnoczi <stefa...@linux.vnet.ibm.com>
> Signed-off-by: Dong Xu Wang <wdon...@linux.vnet.ibm.com>
> ---
> blockdev.c | 53 ++++++++++++++++++++++++++++++++++++++++++----
> docs/live-block-ops.txt | 8 ++++++-
> 2 files changed, 55 insertions(+), 6 deletions(-)
>
> diff --git a/blockdev.c b/blockdev.c
> index d78aa51..c820fcb 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -687,12 +687,55 @@ void qmp_blockdev_snapshot_sync(const char *device,
> const char *snapshot_file,
> return;
> }
>
> - ret = bdrv_img_create(snapshot_file, format, bs->filename,
> - bs->drv->format_name, NULL, -1, flags);
> - if (ret) {
> - error_set(errp, QERR_UNDEFINED_ERROR);
> - return;
> + if (strcmp(format, "add-cow")) {
> + ret = bdrv_img_create(snapshot_file, format, bs->filename,
> + bs->drv->format_name, NULL, -1, flags);
> + if (ret) {
> + error_set(errp, QERR_UNDEFINED_ERROR);
> + return;
> + }
I'm confused here because I thought we need three files:
1. The .add-cow file containing the bitmap
2. The cow image file containing allocated sectors
3. The backing file containing the original image
We're only passing in snapshot_file and bs->filename. How will #2,
the cow file, be created?
Stefan
