block: Fix multiwrite with overlapping requests

With overlapping requests, the total number of sectors is smaller than the sum
of the nb_sectors of both requests.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit cbf1dff2f1033cadcb15c0ffc9c0a3d039d8ed42)

diff --git a/block.c b/block.c
index 955eeaa7b7e5899036244233e5cad2ecf44b9467..298414c92ada9429e6aaeaff47793bf8aab38a16 100644 (file)
--- a/block.c
+++ b/block.c
@@ -1711,7 +1711,7 @@ static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs,
             // Add the second request
             qemu_iovec_concat(qiov, reqs[i].qiov, reqs[i].qiov->size);
 
-            reqs[outidx].nb_sectors += reqs[i].nb_sectors;
+            reqs[outidx].nb_sectors = qiov->size >> 9;
             reqs[outidx].qiov = qiov;
 
             mcb->callbacks[i].free_qiov = reqs[outidx].qiov;