Re: [Qemu-block] [PATCH] vmdk: Set vmdk parent backing_format to vmdk

[Sam Eiderman]

Thanks,

Also please notice that the mentioned commit in the commit message has it’s commit id changed to b69864e.

Sam

On 27 Mar 2019, at 2:35, Eric Blake <address@hidden> wrote:

On 3/26/19 2:58 PM, Sam Eiderman wrote:

Commit fb2105b ("vmdk: Support version=3 in VMDK descriptor files") fixed
the probe function to correctly guess vmdk descriptors with version=3.

All patches need to cc qemu-devel in addition to their maintainers (I've
added that now).

This solves the issue where vmdk snapshot with parent vmdk descriptor
containing "version=3" would be treated as raw instead vmdk.

In the future case where a new vmdk version is introduced, we will again
experience this issue, even if the user will provide "-f vmdk" it will
only apply to the tip image and not to the underlying "misprobed" parent
image.

The code in vmdk.c already assumes that the backing file of vmdk must be
vmdk (see vmdk_is_cid_valid which returns 0 if backing file is not
vmdk).

So let's make it official by supplying the backing_format as vmdk.

Reviewed-by: Mark Kanda <address@hidden>
Reviewed-By: Liran Alon <address@hidden>
Reviewed-by: Arbel Moshe <address@hidden>
Signed-off-by: Shmuel Eiderman <address@hidden>
---
block/vmdk.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/block/vmdk.c b/block/vmdk.c
index 8dec6ef767..de8cb859f8 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -397,6 +397,8 @@ static int vmdk_parent_open(BlockDriverState *bs)
        pstrcpy(bs->auto_backing_file, end_name - p_name + 1, p_name);
        pstrcpy(bs->backing_file, sizeof(bs->backing_file),
                bs->auto_backing_file);
+        pstrcpy(bs->backing_format, sizeof(bs->backing_format),
+                "vmdk");
    }

Reviewed-by: Eric Blake <address@hidden>

Makes sense for 4.0-rc2.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org