On 10/11/19 10:28 AM, Max Reitz wrote:
The qcow2 specification says to ignore unknown extra data fields in
snapshot table entries. Currently, we discard it whenever we update the
image, which is a bit different from "ignore".
This patch makes the qcow2 driver keep all unknown extra data fields
when updating an image's snapshot table.
Signed-off-by: Max Reitz <[email protected]>
Reviewed-by: Eric Blake <[email protected]>
---
/* Bitmap header extension constraints */
#define QCOW2_MAX_BITMAPS 65535
#define QCOW2_MAX_BITMAP_DIRECTORY_SIZE (1024 * QCOW2_MAX_BITMAPS)
@@ -181,6 +184,8 @@ typedef struct QCowSnapshot {
uint32_t date_sec;
uint32_t date_nsec;
uint64_t vm_clock_nsec;
+ uint32_t extra_data_size;
+ void *unknown_extra_data; /* Extra data past QCowSnapshotExtraData */
Would it be worth a comment change:
uint32_t extra_data_size; /* Size of all extra data, including
QCowSnapshotExtraData */
void *unknown_extra_data; /* Data beyond QCowSnapshotExtraData, if any */
Either way, R-b stands.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
