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Re: [Qemu-devel] [for 3.1? PATCH] qcow2: Assert that refcount block offs
From: |
Alberto Garcia |
Subject: |
Re: [Qemu-devel] [for 3.1? PATCH] qcow2: Assert that refcount block offsets fit in the refcount table |
Date: |
Wed, 14 Nov 2018 08:10:47 +0100 |
User-agent: |
Notmuch/0.18.2 (http://notmuchmail.org) Emacs/24.4.1 (i586-pc-linux-gnu) |
On Tue 13 Nov 2018 06:06:54 PM CET, Eric Blake <address@hidden> wrote:
>> Refcount table entries have a field to store the offset of the
>> refcount block. The rest of the bits of the entry are currently
>> reserved.
>>
>> The offset is always taken from the entry using REFT_OFFSET_MASK to
>> ensure that we only use the bits that belong to that field.
>>
>> While that mask is used every time we read from the refcount table, it
>> is never used when we write to it. Due to the other constraints of the
>> qcow2 format QEMU can never produce refcount block offsets that don't
>> fit in that field so any such offset when allocating a refcount block
>> would indicate a bug in QEMU.
>> ---
>> block/qcow2-refcount.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>
> Reviewed-by: Eric Blake <address@hidden>
Yes, for 3.1, shall I resend it with the updated subject message?
Berto