[Qemu-devel] [PATCH V12 06/18] block: add check for VM snapshot in bdrv_query_snapshot_info_list()

[Wenchao Xia]

  This patch adds a parameter to tell whether return valid snapshots
for whole VM only.
  Note that the snapshot check logic is copied from do_info_snapshots(),
which is different with load_vmstate() and will be changed in next patch.

Signed-off-by: Wenchao Xia <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Reviewed-by: Kevin Wolf <address@hidden>
---
 block/qapi.c         |   39 +++++++++++++++++++++++++++++++++++++--
 include/block/qapi.h |    1 +
 qemu-img.c           |    2 +-
 3 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/block/qapi.c b/block/qapi.c
index 9bfa547..97c5cd4 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -23,15 +23,48 @@
  */
 
 #include "block/qapi.h"
+#include "block/snapshot.h"
 #include "block/block_int.h"
 
 /*
+ * check whether the snapshot is valid for whole vm.
+ *
+ * @sn: snapshot info to be checked.
+ * @bs: where @sn was found.
+ *
+ * return true if the snapshot is consistent for the VM.
+ */
+static bool snapshot_valid_for_vm(const QEMUSnapshotInfo *sn,
+                                  BlockDriverState *bs)
+{
+    BlockDriverState *bs1 = NULL;
+    QEMUSnapshotInfo s, *sn_info = &s;
+    int ret;
+
+    /* 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 (bs1 != bs && bdrv_can_snapshot(bs1)) {
+            ret = bdrv_snapshot_find(bs1, sn_info, sn->id_str, NULL);
+            if (ret < 0) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+/*
  * Returns 0 on success, with *p_list either set to describe snapshot
  * information, or NULL because there are no snapshots.  Returns -errno on
- * error, with *p_list untouched.
+ * error, with *p_list untouched. If @vm_snapshot is true, limit the results
+ * to snapshots valid for the whole VM.
  */
 int bdrv_query_snapshot_info_list(BlockDriverState *bs,
                                   SnapshotInfoList **p_list,
+                                  bool vm_snapshot,
                                   Error **errp)
 {
     int i, sn_count;
@@ -60,7 +93,9 @@ int bdrv_query_snapshot_info_list(BlockDriverState *bs,
     }
 
     for (i = 0; i < sn_count; i++) {
-
+        if (vm_snapshot && !snapshot_valid_for_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 91dc41b..fe66053 100644
--- a/include/block/qapi.h
+++ b/include/block/qapi.h
@@ -30,6 +30,7 @@
 
 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 472b264..f537014 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1735,7 +1735,7 @@ static ImageInfoList *collect_image_info_list(const char 
*filename,
 
         info = g_new0(ImageInfo, 1);
         bdrv_collect_image_info(bs, info, filename);
-        bdrv_query_snapshot_info_list(bs, &info->snapshots, NULL);
+        bdrv_query_snapshot_info_list(bs, &info->snapshots, false, NULL);
         if (info->snapshots) {
             info->has_snapshots = true;
         }
-- 
1.7.1