3 files changed, 33 insertions, 0 deletions
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 8dd5df0..aacf357 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -418,3 +418,34 @@ int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
     return s->nb_snapshots;
 }
 
+int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name)
+{
+    int i, snapshot_index, l1_size2;
+    BDRVQcowState *s = bs->opaque;
+    QCowSnapshot *sn;
+
+    snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_name);
+    if (snapshot_index < 0) {
+        return -ENOENT;
+    }
+
+    sn = &s->snapshots[snapshot_index];
+    s->l1_size = sn->l1_size;
+    l1_size2 = s->l1_size * sizeof(uint64_t);
+    if (s->l1_table != NULL) {
+        qemu_free(s->l1_table);
+    }
+
+    s->l1_table_offset = sn->l1_table_offset;
+    s->l1_table = qemu_mallocz(align_offset(l1_size2, 512));
+
+    if (bdrv_pread(bs->file, sn->l1_table_offset,
+                   s->l1_table, l1_size2) != l1_size2) {
+        return -1;
+    }
+
+    for(i = 0;i < s->l1_size; i++) {
+        be64_to_cpus(&s->l1_table[i]);
+    }
+    return 0;
+}
diff --git a/block/qcow2.c b/block/qcow2.c
index 45ed073..b816d87 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1286,6 +1286,7 @@ static BlockDriver bdrv_qcow2 = {
     .bdrv_snapshot_goto     = qcow2_snapshot_goto,
     .bdrv_snapshot_delete   = qcow2_snapshot_delete,
     .bdrv_snapshot_list     = qcow2_snapshot_list,
+    .bdrv_snapshot_load_tmp     = qcow2_snapshot_load_tmp,
     .bdrv_get_info	= qcow_get_info,
 
     .bdrv_save_vmstate    = qcow_save_vmstate,
diff --git a/block/qcow2.h b/block/qcow2.h
index add710b..2d22e5e 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -211,6 +211,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
+int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
 
 void qcow2_free_snapshots(BlockDriverState *bs);
 int qcow2_read_snapshots(BlockDriverState *bs);