Re: [Qemu-devel] [PATCH 06/11] snapshot: distinguish id and name in snapshot delete

[Wenchao Xia]

于 2013-6-11 17:25, Stefan Hajnoczi 写道:
On Sat, Jun 08, 2013 at 02:58:02PM +0800, Wenchao Xia wrote:
  static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)

I suggest renaming the argument to make it less confusing: const char 
*name_or_id

  will rename it.

  {
-    BDRVQcowState *s = bs->opaque;
-    int i, ret;
+    int ret;

-    ret = find_snapshot_by_id(bs, name);
+    ret = find_snapshot_by_id_and_name(bs, name, NULL);
      if (ret >= 0)
          return ret;

Since you're touching the other lines in this function you could add {}.

 OK.

-    for(i = 0; i < s->nb_snapshots; i++) {
-        if (!strcmp(s->snapshots[i].name, name))
-            return i;
-    }
-    return -1;
+    return find_snapshot_by_id_and_name(bs, NULL, name);
  }

  /* if no id is provided, a new one is constructed */
@@ -333,7 +347,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, 
QEMUSnapshotInfo *sn_info)
      }

      /* Check that the ID is unique */
-    if (find_snapshot_by_id(bs, sn_info->id_str) >= 0) {
+    if (find_snapshot_by_id_and_name(bs, sn_info->id_str, NULL) >= 0) {
          return -EEXIST;
      }

@@ -530,15 +544,21 @@ fail:
      return ret;
  }

-int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
+int qcow2_snapshot_delete(BlockDriverState *bs,
+                          const char *snapshot_id,
+                          const char *name,
+                          Error **errp)

This patch will fail to compile.  You haven't changed the
.bdrv_snapshot_delete() prototype.

Please make sure every patch compiles.

  shouldn't following line in this patch changed the prototype?

--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -157,7 +157,10 @@ struct BlockDriver {
                                 QEMUSnapshotInfo *sn_info);
     int (*bdrv_snapshot_goto)(BlockDriverState *bs,
                               const char *snapshot_id);
-    int (*bdrv_snapshot_delete)(BlockDriverState *bs, const char 
*snapshot_id);
+    int (*bdrv_snapshot_delete)(BlockDriverState *bs,
+                                const char *snapshot_id,
+                                const char *name,
+                                Error **errp);

  let me retry.

  {
      BDRVQcowState *s = bs->opaque;
      QCowSnapshot sn;
      int snapshot_index, ret;

      /* Search the snapshot */
-    snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
+    snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
      if (snapshot_index < 0) {
+        error_setg(errp,
+                   "Can't find a snapshot with ID %s and name %s",
+                   snapshot_id, name);

Are both snapshot_id and name guaranteed to be non-NULL here?  It is
dangerous to pass NULL strings to sprintf() functions.  IIRC some libc
implementations will crash, others will print "(null)" like Linux.

  OK, will check it.


--
Best Regards

Wenchao Xia