[Qemu-devel] [PATCH v8 01/16] block: Release dirty bitmaps in bdrv_close()

[Max Reitz <mreitz@redhat.com>]

bdrv_delete() is not very happy about deleting BlockDriverStates with
dirty bitmaps still attached to them. In the past, we got around that
very easily by relying on bdrv_close_all() bypassing bdrv_delete(), and
bdrv_close() simply ignoring that condition. We should fix that by
releasing all dirty bitmaps in bdrv_close() and drop the assertion in
bdrv_delete().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
---
 block.c | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/block.c b/block.c
index 5709d3d..9a31e20 100644
--- a/block.c
+++ b/block.c
@@ -88,6 +88,8 @@ static int bdrv_open_inherit(BlockDriverState **pbs, const char *filename,
                              const BdrvChildRole *child_role, Error **errp);
 
 static void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
+static void bdrv_release_all_dirty_bitmaps(BlockDriverState *bs);
+
 /* If non-zero, use only whitelisted block drivers */
 static int use_bdrv_whitelist;
 
@@ -2157,6 +2159,8 @@ void bdrv_close(BlockDriverState *bs)
 
     notifier_list_notify(&bs->close_notifiers, bs);
 
+    bdrv_release_all_dirty_bitmaps(bs);
+
     if (bs->blk) {
         blk_dev_change_media_cb(bs->blk, false);
     }
@@ -2366,7 +2370,6 @@ static void bdrv_delete(BlockDriverState *bs)
     assert(!bs->job);
     assert(bdrv_op_blocker_is_empty(bs));
     assert(!bs->refcnt);
-    assert(QLIST_EMPTY(&bs->dirty_bitmaps));
 
     bdrv_close(bs);
 
@@ -3582,21 +3585,39 @@ static void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
     }
 }
 
-void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
+static void bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs,
+                                                  BdrvDirtyBitmap *bitmap)
 {
     BdrvDirtyBitmap *bm, *next;
     QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
-        if (bm == bitmap) {
+        if (!bitmap || bm == bitmap) {
             assert(!bdrv_dirty_bitmap_frozen(bm));
-            QLIST_REMOVE(bitmap, list);
-            hbitmap_free(bitmap->bitmap);
-            g_free(bitmap->name);
-            g_free(bitmap);
-            return;
+            QLIST_REMOVE(bm, list);
+            hbitmap_free(bm->bitmap);
+            g_free(bm->name);
+            g_free(bm);
+
+            if (bitmap) {
+                return;
+            }
         }
     }
 }
 
+void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
+{
+    bdrv_do_release_matching_dirty_bitmap(bs, bitmap);
+}
+
+/**
+ * Release all dirty bitmaps attached to a BDS (for use in bdrv_close()). There
+ * must not be any frozen bitmaps attached.
+ */
+static void bdrv_release_all_dirty_bitmaps(BlockDriverState *bs)
+{
+    bdrv_do_release_matching_dirty_bitmap(bs, NULL);
+}
+
 void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 {
     assert(!bdrv_dirty_bitmap_frozen(bitmap));
-- 
2.7.0