qmp: Add support of "dirty-bitmap" sync mode for drive-backup

For "dirty-bitmap" sync mode, the block job will iterate through the
given dirty bitmap to decide if a sector needs backup (backup all the
dirty clusters and skip clean ones), just as allocation conditions of
"top" sync mode.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1429314609-29776-11-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/block.c b/block.c
index dffa9dedc0..9dc5c8cb1a 100644
--- a/block.c
+++ b/block.c
@@ -5783,6 +5783,15 @@ static void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector,
     }
 }
 
+/**
+ * Advance an HBitmapIter to an arbitrary offset.
+ */
+void bdrv_set_dirty_iter(HBitmapIter *hbi, int64_t offset)
+{
+    assert(hbi->hb);
+    hbitmap_iter_init(hbi, hbi->hb, offset);
+}
+
 int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
 {
     return hbitmap_count(bitmap->bitmap);