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Re: [Qemu-devel] [PATCH] QCOW2: bug fix - read base image beyond its siz
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH] QCOW2: bug fix - read base image beyond its size |
Date: |
Mon, 07 Feb 2011 14:48:47 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101027 Fedora/3.0.10-1.fc12 Thunderbird/3.0.10 |
Am 03.02.2011 16:12, schrieb Chunqiang Tang:
> This patch fixes the following bug in QCOW2. For a QCOW2 image that is larger
> than its base image, when handling a read request straddling over the end of
> the
> base image, the QCOW2 driver attempts to read beyond the end of the base image
> and the request would fail.
>
> This bug was found by Fast Virtual Disk (FVD)'s fully automated testing tool.
> The following test triggered the bug.
>
> dd if=/dev/zero of=/var/ramdisk/truth.raw count=0 bs=1 seek=1098561536
> dd if=/dev/zero of=/var/ramdisk/zero-500M.raw count=0 bs=1 seek=593099264
> ./qemu-img create -f qcow2 -ocluster_size=65536,backing_fmt=blksim -b
> /var/ramdisk/zero-500M.raw /var/ramdisk/test.qcow2 1098561536
> ./qemu-io --auto --seed=30477694 --truth=/var/ramdisk/truth.raw
> --format=qcow2 --test=blksim:/var/ramdisk/test.qcow2 --verify_write=true
> --compare_before=false --compare_after=true --round=100000 --parallel=100
> --io_size=10485760 --fail_prob=0 --cancel_prob=0 --instant_qemubh=true
>
> Signed-off-by: Chunqiang Tang <address@hidden>
Thanks, fixed up the coding style (whitespace) and applied to the block
branch.
However, I wonder if we can't share some code between
qemu_iovec_memset_skip and qemu_iovec_copy. I think a cleanup patch
would be possible there.
Kevin