diff mbox series

[v2,3/4] qcow2: Tighten cluster_offset alignment assertions

Message ID fe47feb4fc96cf1242ba9e9431f910aef575cf16.1578596897.git.berto@igalia.com (mailing list archive)
State New, archived
Headers show
Series qcow2: Misc BDRV_SECTOR_SIZE updates | expand

Commit Message

Alberto Garcia Jan. 9, 2020, 7:13 p.m. UTC
qcow2_alloc_cluster_offset() and qcow2_get_cluster_offset() always
return offsets that are cluster-aligned so don't just check that they
are sector-aligned.

The check in qcow2_co_preadv_task() is also replaced by an assertion
for the same reason.

Signed-off-by: Alberto Garcia <berto@igalia.com>
---
 block/qcow2.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

Comments

Alberto Garcia Jan. 10, 2020, 12:14 p.m. UTC | #1
On Thu 09 Jan 2020 08:13:01 PM CET, Alberto Garcia wrote:
> -        assert((cluster_offset & 511) == 0);
> +        assert(QEMU_IS_ALIGNED(cluster_offset, s->cluster_size));

On second thoughts this patch could also use the (probably more
efficient) offset_into_cluster() call instead.

I can resend it if you think it's a good idea.

Berto
Max Reitz Jan. 14, 2020, 1:56 p.m. UTC | #2
On 09.01.20 20:13, Alberto Garcia wrote:
> qcow2_alloc_cluster_offset() and qcow2_get_cluster_offset() always
> return offsets that are cluster-aligned so don't just check that they
> are sector-aligned.
> 
> The check in qcow2_co_preadv_task() is also replaced by an assertion
> for the same reason.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  block/qcow2.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>
Max Reitz Jan. 14, 2020, 1:58 p.m. UTC | #3
On 10.01.20 13:14, Alberto Garcia wrote:
> On Thu 09 Jan 2020 08:13:01 PM CET, Alberto Garcia wrote:
>> -        assert((cluster_offset & 511) == 0);
>> +        assert(QEMU_IS_ALIGNED(cluster_offset, s->cluster_size));
> 
> On second thoughts this patch could also use the (probably more
> efficient) offset_into_cluster() call instead.
> 
> I can resend it if you think it's a good idea.
Either way works for me.  (I don’t think it’s going to make any
difference in practice, but of course, why not.)

Max
diff mbox series

Patch

diff --git a/block/qcow2.c b/block/qcow2.c
index 848a6c5182..783d2b9578 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2175,10 +2175,7 @@  static coroutine_fn int qcow2_co_preadv_task(BlockDriverState *bs,
                                           offset, bytes, qiov, qiov_offset);
 
     case QCOW2_CLUSTER_NORMAL:
-        if ((file_cluster_offset & 511) != 0) {
-            return -EIO;
-        }
-
+        assert(QEMU_IS_ALIGNED(file_cluster_offset, s->cluster_size));
         if (bs->encrypted) {
             return qcow2_co_preadv_encrypted(bs, file_cluster_offset,
                                              offset, bytes, qiov, qiov_offset);
@@ -2514,7 +2511,7 @@  static coroutine_fn int qcow2_co_pwritev_part(
             goto out_locked;
         }
 
-        assert((cluster_offset & 511) == 0);
+        assert(QEMU_IS_ALIGNED(cluster_offset, s->cluster_size));
 
         ret = qcow2_pre_write_overlap_check(bs, 0,
                                             cluster_offset + offset_in_cluster,
@@ -3904,7 +3901,7 @@  qcow2_co_copy_range_to(BlockDriverState *bs,
             goto fail;
         }
 
-        assert((cluster_offset & 511) == 0);
+        assert(QEMU_IS_ALIGNED(cluster_offset, s->cluster_size));
 
         ret = qcow2_pre_write_overlap_check(bs, 0,
                 cluster_offset + offset_in_cluster, cur_bytes, true);