[Qemu-block] [PATCH v2 8/9] block: Fix bdrv_co_truncate overlap check

[Fam Zheng]

If we are growing the image and potentially using preallocation for the
new area, we need to make sure that no write requests are made to the
"preallocated" area which [@old_size, @offset), not [@offset, offset * 2
- @old_size).

Signed-off-by: Fam Zheng <f...@redhat.com>
---
 block/io.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/io.c b/block/io.c
index d07849fa96..ed18eb0ca3 100644
--- a/block/io.c
+++ b/block/io.c
@@ -3070,7 +3070,8 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, 
int64_t offset,
     }
 
     bdrv_inc_in_flight(bs);
-    tracked_request_begin(&req, bs, offset, new_bytes, BDRV_TRACKED_TRUNCATE);
+    tracked_request_begin(&req, bs, offset - new_bytes, new_bytes,
+                          BDRV_TRACKED_TRUNCATE);
 
     /* If we are growing the image and potentially using preallocation for the
      * new area, we need to make sure that no write requests are made to it
-- 
2.17.1