[Qemu-devel] [PATCH v2 2/3] qcow2: Do not mark inactive images corrupt

Max Reitz posted 3 patches 7 years, 4 months ago
[Qemu-devel] [PATCH v2 2/3] qcow2: Do not mark inactive images corrupt
Posted by Max Reitz 7 years, 4 months ago
When signaling a corruption on a read-only image, qcow2 already makes
fatal events non-fatal (i.e., they will not result in the image being
closed, and the image header's corrupt flag will not be set).  This is
necessary because we cannot set the corrupt flag on read-only images,
and it is possible because further corruption of read-only images is
impossible.

Inactive images are effectively read-only, too, so we should do the same
for them.  bdrv_is_writable() can tell us whether an image can actually
be written to, so use its result instead of !bs->read_only.

(Otherwise, the assert(!(bs->open_flags & BDRV_O_INACTIVE)) in
bdrv_co_pwritev() will fail, crashing qemu.)

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/qcow2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index 6b2d88759d..6fa5e1d71a 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -4569,7 +4569,7 @@ void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
     char *message;
     va_list ap;
 
-    fatal = fatal && !bs->read_only;
+    fatal = fatal && bdrv_is_writable(bs);
 
     if (s->signaled_corruption &&
         (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT)))
-- 
2.17.0


Re: [Qemu-devel] [PATCH v2 2/3] qcow2: Do not mark inactive images corrupt
Posted by Jeff Cody 7 years, 4 months ago
On Wed, Jun 06, 2018 at 09:37:01PM +0200, Max Reitz wrote:
> When signaling a corruption on a read-only image, qcow2 already makes
> fatal events non-fatal (i.e., they will not result in the image being
> closed, and the image header's corrupt flag will not be set).  This is
> necessary because we cannot set the corrupt flag on read-only images,
> and it is possible because further corruption of read-only images is
> impossible.
> 
> Inactive images are effectively read-only, too, so we should do the same
> for them.  bdrv_is_writable() can tell us whether an image can actually
> be written to, so use its result instead of !bs->read_only.
> 
> (Otherwise, the assert(!(bs->open_flags & BDRV_O_INACTIVE)) in
> bdrv_co_pwritev() will fail, crashing qemu.)
> 
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Max Reitz <mreitz@redhat.com>

Reviewed-by: Jeff Cody <jcody@redhat.com>

> ---
>  block/qcow2.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 6b2d88759d..6fa5e1d71a 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -4569,7 +4569,7 @@ void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
>      char *message;
>      va_list ap;
>  
> -    fatal = fatal && !bs->read_only;
> +    fatal = fatal && bdrv_is_writable(bs);
>  
>      if (s->signaled_corruption &&
>          (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT)))
> -- 
> 2.17.0
>