@@ -48,6 +48,7 @@ typedef struct QEMU_PACKED QCowSnapshotHeader {
typedef struct QEMU_PACKED QCowSnapshotExtraData {
uint64_t vm_state_size_large;
+ uint64_t disk_size;
} QCowSnapshotExtraData;
void qcow2_free_snapshots(BlockDriverState *bs)
@@ -117,6 +118,12 @@ int qcow2_read_snapshots(BlockDriverState *bs)
sn->vm_state_size = be64_to_cpu(extra.vm_state_size_large);
}
+ if (extra_data_size >= 16) {
+ sn->disk_size = be64_to_cpu(extra.disk_size);
+ } else {
+ sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
+ }
+
/* Read snapshot ID */
sn->id_str = g_malloc(id_str_size + 1);
ret = bdrv_pread(bs->file, offset, sn->id_str, id_str_size);
@@ -197,6 +204,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
memset(&extra, 0, sizeof(extra));
extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size);
+ extra.disk_size = cpu_to_be64(sn->disk_size);
id_str_size = strlen(sn->id_str);
name_size = strlen(sn->name);
@@ -330,6 +338,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
sn->id_str = g_strdup(sn_info->id_str);
sn->name = g_strdup(sn_info->name);
+ sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
sn->vm_state_size = sn_info->vm_state_size;
sn->date_sec = sn_info->date_sec;
sn->date_nsec = sn_info->date_nsec;
@@ -426,6 +435,13 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
}
sn = &s->snapshots[snapshot_index];
+ if (sn->disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) {
+ error_report("qcow2: Loading snapshots with different disk "
+ "size is not implemented");
+ ret = -ENOTSUP;
+ goto fail;
+ }
+
/*
* Make sure that the current L1 table is big enough to contain the whole
* L1 table of the snapshot. If the snapshot L1 table is smaller, the
@@ -78,6 +78,7 @@ typedef struct QCowSnapshot {
uint32_t l1_size;
char *id_str;
char *name;
+ uint64_t disk_size;
uint64_t vm_state_size;
uint32_t date_sec;
uint32_t date_nsec;
This allows that different snapshots of an image can have different sizes, which is a requirement for enabling image resizing even with images that have internal snapshots. We don't do the actual support for it now, but make sure that the additional field is present and not completely ignored in all version 3 images. When trying to load a snapshot of different size, it returns an error. Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/qcow2-snapshot.c | 16 ++++++++++++++++ block/qcow2.h | 1 + 2 files changed, 17 insertions(+), 0 deletions(-)