Merge remote-tracking branch 'remotes/berrange/tags/pull-qio-2017-04-04-1' into staging

[mirror_qemu.git] / blockdev.c

diff --git a/blockdev.c b/blockdev.c
index ff781d9df32b4017afbb0f17b8df960c1ca0a652..040c152512be469680cfde7ef3175c2024761dc7 100644 (file)
--- a/blockdev.c
+++ b/blockdev.c
@@ -1614,6 +1614,7 @@ typedef struct ExternalSnapshotState {
     BlockDriverState *old_bs;
     BlockDriverState *new_bs;
     AioContext *aio_context;
+    bool overlay_appended;
 } ExternalSnapshotState;
 
 static void external_snapshot_prepare(BlkActionState *common,
@@ -1768,7 +1769,19 @@ static void external_snapshot_prepare(BlkActionState *common,
 
     if (!state->new_bs->drv->supports_backing) {
         error_setg(errp, "The snapshot does not support backing images");
+        return;
+    }
+
+    /* This removes our old bs and adds the new bs. This is an operation that
+     * can fail, so we need to do it in .prepare; undoing it for abort is
+     * always possible. */
+    bdrv_ref(state->new_bs);
+    bdrv_append(state->new_bs, state->old_bs, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
     }
+    state->overlay_appended = true;
 }
 
 static void external_snapshot_commit(BlkActionState *common)
@@ -1778,8 +1791,6 @@ static void external_snapshot_commit(BlkActionState *common)
 
     bdrv_set_aio_context(state->new_bs, state->aio_context);
 
-    /* This removes our old bs and adds the new bs */
-    bdrv_append(state->new_bs, state->old_bs);
     /* We don't need (or want) to use the transactional
      * bdrv_reopen_multiple() across all the entries at once, because we
      * don't want to abort all of them if one of them fails the reopen */
@@ -1794,7 +1805,9 @@ static void external_snapshot_abort(BlkActionState *common)
     ExternalSnapshotState *state =
                              DO_UPCAST(ExternalSnapshotState, common, common);
     if (state->new_bs) {
-        bdrv_unref(state->new_bs);
+        if (state->overlay_appended) {
+            bdrv_replace_node(state->new_bs, state->old_bs, &error_abort);
+        }
     }
 }
 
@@ -1805,6 +1818,7 @@ static void external_snapshot_clean(BlkActionState *common)
     if (state->aio_context) {
         bdrv_drained_end(state->old_bs);
         aio_context_release(state->aio_context);
+        bdrv_unref(state->new_bs);
     }
 }
 
@@ -2033,7 +2047,9 @@ static void block_dirty_bitmap_clear_abort(BlkActionState *common)
     BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
                                              common, common);
 
-    bdrv_undo_clear_dirty_bitmap(state->bitmap, state->backup);
+    if (state->backup) {
+        bdrv_undo_clear_dirty_bitmap(state->bitmap, state->backup);
+    }
 }
 
 static void block_dirty_bitmap_clear_commit(BlkActionState *common)
@@ -2819,7 +2835,7 @@ void hmp_drive_del(Monitor *mon, const QDict *qdict)
 
     bs = bdrv_find_node(id);
     if (bs) {
-        qmp_x_blockdev_del(id, &local_err);
+        qmp_blockdev_del(id, &local_err);
         if (local_err) {
             error_report_err(local_err);
         }
@@ -3884,7 +3900,7 @@ fail:
     visit_free(v);
 }
 
-void qmp_x_blockdev_del(const char *node_name, Error **errp)
+void qmp_blockdev_del(const char *node_name, Error **errp)
 {
     AioContext *aio_context;
     BlockDriverState *bs;