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Re: [Qemu-block] [PATCH v2] qcow2: Assert that refcount block offsets fi
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-block] [PATCH v2] qcow2: Assert that refcount block offsets fit in the refcount table |
Date: |
Tue, 8 Jan 2019 16:53:55 +0100 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
Am 14.11.2018 um 15:58 hat Alberto Garcia geschrieben:
> 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.
>
> Signed-off-by: Alberto Garcia <address@hidden>
> Reviewed-by: Eric Blake <address@hidden>
Thanks, applied to the block branch.
Kevin