[Qemu-devel] [PATCH v6 03/15] block: Release dirty bitmaps in bdrv_close()

[Max Reitz]

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 <mre...@redhat.com>
---
 block.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/block.c b/block.c
index 3493501..23448ed 100644
--- a/block.c
+++ b/block.c
@@ -87,6 +87,8 @@ 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;
 
@@ -1916,6 +1918,8 @@ void bdrv_close(BlockDriverState *bs)
     bdrv_drain(bs); /* in case flush left pending I/O */
     notifier_list_notify(&bs->close_notifiers, bs);
 
+    bdrv_release_all_dirty_bitmaps(bs);
+
     if (bs->blk) {
         blk_dev_change_media_cb(bs->blk, false);
     }
@@ -2123,7 +2127,6 @@ 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);
 
@@ -3318,6 +3321,21 @@ void bdrv_release_dirty_bitmap(BlockDriverState *bs, 
BdrvDirtyBitmap *bitmap)
     }
 }
 
+/**
+ * Release all dirty bitmaps attached to a BDS, independently of whether they
+ * are frozen or not (for use in bdrv_close()).
+ */
+static void bdrv_release_all_dirty_bitmaps(BlockDriverState *bs)
+{
+    BdrvDirtyBitmap *bm, *next;
+    QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
+        QLIST_REMOVE(bm, list);
+        hbitmap_free(bm->bitmap);
+        g_free(bm->name);
+        g_free(bm);
+    }
+}
+
 void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 {
     assert(!bdrv_dirty_bitmap_frozen(bitmap));
-- 
2.6.2