[v9,01/13] block/backup: fix backup_cow_with_offload for last cluster
diff mbox series

Message ID 20190826161312.489398-2-vsementsov@virtuozzo.com
State New
Headers show
Series
  • backup-top filter driver for backup
Related show

Commit Message

Vladimir Sementsov-Ogievskiy Aug. 26, 2019, 4:13 p.m. UTC
We shouldn't try to copy bytes beyond EOF. Fix it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/backup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Max Reitz Aug. 28, 2019, 2:08 p.m. UTC | #1
On 26.08.19 18:13, Vladimir Sementsov-Ogievskiy wrote:
> We shouldn't try to copy bytes beyond EOF. Fix it.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/backup.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block/backup.c b/block/backup.c
> index 2baf7bed65..33b144305f 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -161,7 +161,7 @@ static int coroutine_fn backup_cow_with_offload(BackupBlockJob *job,
>  
>      assert(QEMU_IS_ALIGNED(job->copy_range_size, job->cluster_size));
>      assert(QEMU_IS_ALIGNED(start, job->cluster_size));
> -    nbytes = MIN(job->copy_range_size, end - start);
> +    nbytes = MIN(job->copy_range_size, MIN(end - start, job->len - start));

Might be easier to read as MIN(end, job->len) - start, but either way:

Reviewed-by: Max Reitz <mreitz@redhat.com>

>      nr_clusters = DIV_ROUND_UP(nbytes, job->cluster_size);
>      bdrv_reset_dirty_bitmap(job->copy_bitmap, start,
>                              job->cluster_size * nr_clusters);
>

Patch
diff mbox series

diff --git a/block/backup.c b/block/backup.c
index 2baf7bed65..33b144305f 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -161,7 +161,7 @@  static int coroutine_fn backup_cow_with_offload(BackupBlockJob *job,
 
     assert(QEMU_IS_ALIGNED(job->copy_range_size, job->cluster_size));
     assert(QEMU_IS_ALIGNED(start, job->cluster_size));
-    nbytes = MIN(job->copy_range_size, end - start);
+    nbytes = MIN(job->copy_range_size, MIN(end - start, job->len - start));
     nr_clusters = DIV_ROUND_UP(nbytes, job->cluster_size);
     bdrv_reset_dirty_bitmap(job->copy_bitmap, start,
                             job->cluster_size * nr_clusters);