[Qemu-devel] [PATCH V8 08/20] block: add filter for vm snapshot in bdrv_query_snapshot_info_list()

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

  This patch adds a parameter to tell whether return valid snapshots
for whole VM only.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
---
 block/qapi.c         |   39 +++++++++++++++++++++++++++++++++++++--
 include/block/qapi.h |    1 +
 qemu-img.c           |    3 ++-
 3 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/block/qapi.c b/block/qapi.c
index b503cfa..a90b4c7 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -12,11 +12,44 @@
  */
 
 #include "block/qapi.h"
+#include "block/snapshot.h"
 #include "block/block_int.h"
 
-/* return 0 on success, and @p_list will be set only on success. */
+/*
+ * check whether the snapshot is valid for whole vm.
+ *
+ * @sn: snapshot info need to be checked.
+ * @bs: where @sn was found.
+ *
+ * return 0 if valid, it means load_vmstate() for it could succeed.
+ */
+static int snapshot_filter_vm(const QEMUSnapshotInfo *sn, BlockDriverState *bs)
+{
+    BlockDriverState *bs1 = NULL;
+    QEMUSnapshotInfo s, *sn_info = &s;
+    int ret = 0;
+
+    /* Check logic is connected with load_vmstate():
+       Only check the devices that can snapshot, other devices that can't
+       take snapshot, for example, readonly ones, will be ignored in
+       load_vmstate(). */
+    while ((bs1 = bdrv_next(bs1))) {
+        if (bdrv_can_snapshot(bs1) && bs1 != bs) {
+            ret = bdrv_snapshot_find(bs1, sn_info, sn->id_str, NULL);
+            if (ret < 0) {
+                ret = -1;
+                break;
+            }
+        }
+    }
+    return ret;
+}
+
+/* return 0 on success, and @p_list will be set only on success. If
+   @vm_snapshot is true, only the snapshot valid for whole vm will be got. */
 int bdrv_query_snapshot_info_list(BlockDriverState *bs,
                                   SnapshotInfoList **p_list,
+                                  bool vm_snapshot,
                                   Error **errp)
 {
     int i, sn_count;
@@ -45,7 +78,9 @@ int bdrv_query_snapshot_info_list(BlockDriverState *bs,
     }
 
     for (i = 0; i < sn_count; i++) {
-
+        if (vm_snapshot && snapshot_filter_vm(&sn_tab[i], bs)) {
+            continue;
+        }
         info = g_new0(SnapshotInfo, 1);
         info->id            = g_strdup(sn_tab[i].id_str);
         info->name          = g_strdup(sn_tab[i].name);
diff --git a/include/block/qapi.h b/include/block/qapi.h
index 030964b..4842c12 100644
--- a/include/block/qapi.h
+++ b/include/block/qapi.h
@@ -6,6 +6,7 @@
 
 int bdrv_query_snapshot_info_list(BlockDriverState *bs,
                                   SnapshotInfoList **p_list,
+                                  bool vm_snapshot,
                                   Error **errp);
 void bdrv_collect_image_info(BlockDriverState *bs,
                              ImageInfo *info,
diff --git a/qemu-img.c b/qemu-img.c
index 32a72f5..7786953 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1735,7 +1735,8 @@ static ImageInfoList *collect_image_info_list(const char *filename,
 
         info = g_new0(ImageInfo, 1);
         bdrv_collect_image_info(bs, info, filename, fmt);
-        if (!bdrv_query_snapshot_info_list(bs, &info->snapshots, NULL)) {
+        if (!bdrv_query_snapshot_info_list(bs, &info->snapshots,
+                                           false, NULL)) {
             info->has_snapshots = true;
         }
 
-- 
1.7.1