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From: Eric Blake <eblake@redhat.com>
To: Hanna Reitz <hreitz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Nir Soffer <nsoffer@redhat.com>,
	qemu-devel@nongnu.org, qemu-block@nongnu.org,
	qemu-stable@nongnu.org
Subject: Re: [PATCH v2 1/2] block/io: Update BSC only if want_zero is true
Date: Fri, 28 Jan 2022 14:46:13 -0600	[thread overview]
Message-ID: <20220128204613.kij3kyw5vcvgx4qx@redhat.com> (raw)
In-Reply-To: <20220118170000.49423-2-hreitz@redhat.com>

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
Virtualization:  qemu.org | libvirt.org



  reply	other threads:[~2022-01-28 20:51 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-18 16:59 [PATCH v2 0/2] block/io: Update BSC only if want_zero is true Hanna Reitz
2022-01-18 16:59 ` [PATCH v2 1/2] " Hanna Reitz
2022-01-28 20:46   ` Eric Blake [this message]
2022-01-18 17:00 ` [PATCH v2 2/2] iotests/block-status-cache: New test Hanna Reitz
2022-01-18 18:02   ` Nir Soffer
2022-01-28 20:50   ` Eric Blake
2022-01-28 22:55     ` Eric Blake

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