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Re: [Qemu-devel] [PATCH v6 05/24] qcow2: Use unsigned addend for update_
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH v6 05/24] qcow2: Use unsigned addend for update_refcount() |
Date: |
Wed, 11 Feb 2015 09:41:40 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 |
On 02/10/2015 01:28 PM, Max Reitz wrote:
> update_refcount() and qcow2_update_cluster_refcount() currently take a
> signed addend. At least one caller passes a value directly derived from
> an absolute refcount that should be reached ("l2_refcount - 1" in
> expand_zero_clusters_in_l1()). Therefore, the addend should be unsigned
> as well; this will be especially important for 64 bit refcounts.
>
> Because update_refcount() then no longer knows whether the refcount
> should be increased or decreased, it now requires an additional flag
> which specified exactly that. The same applies to
> qcow2_update_cluster_refcount().
>
> Signed-off-by: Max Reitz <address@hidden>
> ---
> block/qcow2-cluster.c | 3 ++-
> block/qcow2-refcount.c | 65
> +++++++++++++++++++++++++++++++++-----------------
> block/qcow2.h | 8 ++++++-
> 3 files changed, 52 insertions(+), 24 deletions(-)
>
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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- [Qemu-devel] [PATCH v6 00/24] qcow2: Support refcount orders != 4, Max Reitz, 2015/02/10
- [Qemu-devel] [PATCH v6 01/24] qcow2: Add two new fields to BDRVQcowState, Max Reitz, 2015/02/10
- [Qemu-devel] [PATCH v6 03/24] qcow2: Do not return new value after refcount update, Max Reitz, 2015/02/10
- [Qemu-devel] [PATCH v6 02/24] qcow2: Add refcount_bits to format-specific info, Max Reitz, 2015/02/10
- [Qemu-devel] [PATCH v6 04/24] qcow2: Only return status from qcow2_get_refcount, Max Reitz, 2015/02/10
- [Qemu-devel] [PATCH v6 05/24] qcow2: Use unsigned addend for update_refcount(), Max Reitz, 2015/02/10
- Re: [Qemu-devel] [PATCH v6 05/24] qcow2: Use unsigned addend for update_refcount(),
Eric Blake <=
- [Qemu-devel] [PATCH v6 06/24] qcow2: Use 64 bits for refcount values, Max Reitz, 2015/02/10
- [Qemu-devel] [PATCH v6 10/24] qcow2: Open images with refcount order != 4, Max Reitz, 2015/02/10
- [Qemu-devel] [PATCH v6 08/24] qcow2: Helper function for refcount modification, Max Reitz, 2015/02/10
- [Qemu-devel] [PATCH v6 12/24] qcow2: Use symbolic macros in qcow2_amend_options, Max Reitz, 2015/02/10
- [Qemu-devel] [PATCH v6 07/24] qcow2: Helper for refcount array reallocation, Max Reitz, 2015/02/10
- [Qemu-devel] [PATCH v6 09/24] qcow2: More helpers for refcount modification, Max Reitz, 2015/02/10