Re: [PATCH v2 1/2] block/io: Update BSC only if want_zero is true

[Eric Blake]

On Tue, Jan 18, 2022 at 05:59:59PM +0100, Hanna Reitz wrote:
> We update the block-status cache whenever we get new information from a
> bdrv_co_block_status() call to the block driver.  However, if we have
> passed want_zero=false to that call, it may flag areas containing zeroes
> as data, and so we would update the block-status cache with wrong
> information.
> 
> Therefore, we should not update the cache with want_zero=false.
> 
> Reported-by: Nir Soffer <nsoffer@redhat.com>
> Fixes: 0bc329fbb00 ("block: block-status cache for data regions")
> Reviewed-by: Nir Soffer <nsoffer@redhat.com>
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
> ---
>  block/io.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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