snapshot: create bdrv_all_goto_snapshot helper

to switch to snapshot on all loaded block drivers. The patch also ensures proper locking. Signed-off-by: Denis V. Lunev <[email protected]> Reviewed-by: Greg Kurz <[email protected]> Reviewed-by: Stefan Hajnoczi <[email protected]> Reviewed-by: Fam Zheng <[email protected]> Reviewed-by: Juan Quintela <[email protected]> CC: Kevin Wolf <[email protected]> Tested-by: Greg Kurz <[email protected]> Signed-off-by: Juan Quintela <[email protected]>
dreddy · Nov 19, 2015 · 4c1cdba · 4c1cdba
1 parent 9b00ea3
commit 4c1cdba
Show file tree

Hide file tree

Showing 3 changed files with 26 additions and 10 deletions.
diff --git a/block/snapshot.c b/block/snapshot.c
@@ -403,3 +403,23 @@ int bdrv_all_delete_snapshot(const char *name, BlockDriverState **first_bad_bs,
     *first_bad_bs = bs;
     return ret;
 }
+
+
+int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs)
+{
+    int err = 0;
+    BlockDriverState *bs = NULL;
+
+    while (err == 0 && (bs = bdrv_next(bs))) {
+        AioContext *ctx = bdrv_get_aio_context(bs);
+
+        aio_context_acquire(ctx);
+        if (bdrv_can_snapshot(bs)) {
+            err = bdrv_snapshot_goto(bs, name);
+        }
+        aio_context_release(ctx);
+    }
+
+    *first_bad_bs = bs;
+    return err;
+}
diff --git a/include/block/snapshot.h b/include/block/snapshot.h
@@ -84,5 +84,6 @@ int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs,
 bool bdrv_all_can_snapshot(BlockDriverState **first_bad_bs);
 int bdrv_all_delete_snapshot(const char *name, BlockDriverState **first_bsd_bs,
                              Error **err);
+int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bsd_bs);
 
 #endif
diff --git a/migration/savevm.c b/migration/savevm.c
@@ -2093,16 +2093,11 @@ int load_vmstate(const char *name)
     /* Flush all IO requests so they don't interfere with the new state.  */
     bdrv_drain_all();
 
-    bs = NULL;
-    while ((bs = bdrv_next(bs))) {
-        if (bdrv_can_snapshot(bs)) {
-            ret = bdrv_snapshot_goto(bs, name);
-            if (ret < 0) {
-                error_report("Error %d while activating snapshot '%s' on '%s'",
-                             ret, name, bdrv_get_device_name(bs));
-                return ret;
-            }
-        }
+    ret = bdrv_all_goto_snapshot(name, &bs);
+    if (ret < 0) {
+        error_report("Error %d while activating snapshot '%s' on '%s'",
+                     ret, name, bdrv_get_device_name(bs));
+        return ret;
     }
 
     /* restore the VM state */