@@ -103,6 +103,12 @@ int qcow2_read_snapshots(BlockDriverState *bs)
sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
}
+ if (extra_data_size >= 24) {
+ sn->icount = be64_to_cpu(extra.icount);
+ } else {
+ sn->icount = -1ULL;
+ }
+
/* Read snapshot ID */
sn->id_str = g_malloc(id_str_size + 1);
ret = bdrv_pread(bs->file, offset, sn->id_str, id_str_size);
@@ -209,6 +215,7 @@ 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);
+ extra.icount = cpu_to_be64(sn->icount);
id_str_size = strlen(sn->id_str);
name_size = strlen(sn->name);
@@ -151,6 +151,7 @@ typedef struct QEMU_PACKED QCowSnapshotHeader {
typedef struct QEMU_PACKED QCowSnapshotExtraData {
uint64_t vm_state_size_large;
uint64_t disk_size;
+ uint64_t icount;
} QCowSnapshotExtraData;
@@ -164,6 +165,7 @@ typedef struct QCowSnapshot {
uint32_t date_sec;
uint32_t date_nsec;
uint64_t vm_clock_nsec;
+ uint64_t icount;
} QCowSnapshot;
struct Qcow2Cache;
@@ -506,6 +506,10 @@ Snapshot table entry:
Byte 48 - 55: Virtual disk size of the snapshot in bytes
+ Byte 56 - 63: icount value which corresponds to
+ the record/replay step when the snapshot
+ was taken
+
Version 3 images must include extra data at least up to
byte 55.
This patch introduces the icount field for saving within the snapshot. It is required for navigation between the snapshots in record/replay mode. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> -- v2: - documented format changes in docs/interop/qcow2.txt (suggested by Eric Blake) --- block/qcow2-snapshot.c | 7 +++++++ block/qcow2.h | 2 ++ docs/interop/qcow2.txt | 4 ++++ 3 files changed, 13 insertions(+)