Re: [Qemu-devel] [PATCH V7 05/14] block: add snapshot info query function bdrv_query_snapshot_infolist()

[Wenchao Xia]

于 2013-2-28 23:36, Stefan Hajnoczi 写道:

On Tue, Feb 26, 2013 at 06:40:19PM +0800, Wenchao Xia wrote:

diff --git a/include/block/block.h b/include/block/block.h
index e6d915c..51a14f2 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -319,6 +319,13 @@ void bdrv_get_backing_filename(BlockDriverState *bs,
                                 char *filename, int filename_size);
  void bdrv_get_full_backing_filename(BlockDriverState *bs,
                                      char *dest, size_t sz);
+
+typedef int (*SnapshotFilterFunc)(const QEMUSnapshotInfo *sn, void *opaque);
+/* assume bs is already opened, use qapi_free_* to free returned value. */
+SnapshotInfoList *bdrv_query_snapshot_infolist(BlockDriverState *bs,
+                                               SnapshotFilterFunc filter,
+                                               void *opaque,
+                                               Error **errp);

bdrv_query_snapshot_infolist() uses SnapshotInfoList, therefore it makes
sense to pass a SnapshotInfo argument to SnapshotFilterFunc() instead of
a QEMUSnapshotInfo.  The QEMUSnapshotInfo type is an implementation
detail that should not be part of the API.

  OK.

diff --git a/qemu-img.c b/qemu-img.c
index b650d17..1034cc5 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1280,7 +1280,13 @@ static ImageInfoList *collect_image_info_list(const char 
*filename,

          info = g_new0(ImageInfo, 1);
          collect_image_info(bs, info, filename);
-        collect_snapshots(bs, info);
+        if (bdrv_can_read_snapshot(bs)) {
+            info->snapshots = bdrv_query_snapshot_infolist(bs, NULL,
+                                                           NULL, NULL);
+            if (info->snapshots) {
+                info->has_snapshots = true;
+            }
+        }

bdrv_can_read_snapshot() is not needed.  The code works fine without the
if check.

  OK.

--
Best Regards

Wenchao Xia