From: Stefan Hajnoczi <stefanha@gmail.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org,
qemu-stable@nongnu.org, mreitz@redhat.com
Subject: Re: [Qemu-devel] [Qemu-block] [PATCH] qcow2: Fix qcow2_make_empty() with external data file
Date: Mon, 29 Apr 2019 12:13:31 -0400 [thread overview]
Message-ID: <20190429161331.GC13640@stefanha-x1.localdomain> (raw)
In-Reply-To: <20190429105741.31033-1-kwolf@redhat.com>
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On Mon, Apr 29, 2019 at 12:57:41PM +0200, Kevin Wolf wrote:
> make_completely_empty() is an optimisated path for bdrv_make_empty()
> where completely new metadata is created inside the image file instead
> of going through all clusters and discarding them. For an external data
> file, however, we actually need to do discard operations on the data
> file; just overwriting the qcow2 file doesn't get rid of the data.
>
> The necessary slow path with an explicit discard operation already
> exists for other cases. Use it for external data files, too.
>
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
> block/qcow2.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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WARNING: multiple messages have this Message-ID (diff)
From: Stefan Hajnoczi <stefanha@gmail.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: mreitz@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org,
qemu-stable@nongnu.org
Subject: Re: [Qemu-devel] [Qemu-block] [PATCH] qcow2: Fix qcow2_make_empty() with external data file
Date: Mon, 29 Apr 2019 12:13:31 -0400 [thread overview]
Message-ID: <20190429161331.GC13640@stefanha-x1.localdomain> (raw)
Message-ID: <20190429161331.MyBXPOn3otffbfwKyiwbauL_Br6k607lK5SJQNJkons@z> (raw)
In-Reply-To: <20190429105741.31033-1-kwolf@redhat.com>
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On Mon, Apr 29, 2019 at 12:57:41PM +0200, Kevin Wolf wrote:
> make_completely_empty() is an optimisated path for bdrv_make_empty()
> where completely new metadata is created inside the image file instead
> of going through all clusters and discarding them. For an external data
> file, however, we actually need to do discard operations on the data
> file; just overwriting the qcow2 file doesn't get rid of the data.
>
> The necessary slow path with an explicit discard operation already
> exists for other cases. Use it for external data files, too.
>
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
> block/qcow2.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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next prev parent reply other threads:[~2019-05-01 15:07 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-29 10:57 [Qemu-devel] [PATCH] qcow2: Fix qcow2_make_empty() with external data file Kevin Wolf
2019-04-29 10:57 ` Kevin Wolf
2019-04-29 11:21 ` Kevin Wolf
2019-04-29 11:21 ` Kevin Wolf
2019-04-29 14:40 ` Eric Blake
2019-04-29 14:40 ` Eric Blake
2019-04-29 16:13 ` Stefan Hajnoczi [this message]
2019-04-29 16:13 ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2019-04-30 13:54 ` [Qemu-devel] " no-reply
2019-04-30 13:54 ` no-reply
2019-04-30 15:32 ` Eric Blake
2019-04-30 15:32 ` Eric Blake
2019-04-30 15:42 ` no-reply
2019-04-30 15:42 ` no-reply
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