[Qemu-devel] [PATCH 1/1] block: fix libvirt snapshot with existing bitmaps

["Denis V. Lunev" <den@openvz.org>]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Fix the following bug:

 # virsh start test
 Domain test started

 #  virsh qemu-monitor-command test \
     '{"execute":"block-dirty-bitmap-add",\
      "arguments":{"node":"drive0","name":"ab"}}'
 {"return":{},"id":"libvirt-36"}'}'

 # virsh snapshot-create test
 error: Unable to read from monitor: Connection reset by peer

Actually, assert "assert(pos < hb->size)" in hbitmap_iter_init fires,
because qcow2_save_vmstate just writes to bs (not to bs->file->bs) after
the end of the drive.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
---
 block/dirty-bitmap.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 4902ca5..7b636ee 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -364,6 +364,11 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
                     int nr_sectors)
 {
     BdrvDirtyBitmap *bitmap;
+
+    if (cur_sector >= bdrv_nb_sectors(bs)) {
+        return;
+    }
+
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
         if (!bdrv_dirty_bitmap_enabled(bitmap)) {
             continue;
-- 
2.1.4