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Re: [Qemu-devel] [PATCH v3 0/2] qcow2: Patch for shrinking qcow2 disk im
From: |
Jun Li |
Subject: |
Re: [Qemu-devel] [PATCH v3 0/2] qcow2: Patch for shrinking qcow2 disk image |
Date: |
Wed, 15 Oct 2014 01:56:47 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
Please ignore this patch, I have submit a new version.
On Mon, 10/13 13:04, Jun Li wrote:
> This is the third version for qcow2 shrinking. In this version, fixed host
> cluster leak when shrinking a disk image. Such as:
> Step 1,
> # /opt/qemu-git-arm/bin/qemu-img info /home/lijun/Work/tmp/shrink.qcow2
> image: /home/lijun/Work/tmp/shrink.qcow2
> file format: qcow2
> virtual size: 2.0G (2147483648 bytes)
> disk size: 2.0G
> cluster_size: 65536
> Format specific information:
> compat: 1.1
> lazy refcounts: false
> corrupt: false
>
> Step 2,
> # /opt/qemu-git-arm/bin/qemu-img resize /home/lijun/Work/tmp/shrink.qcow2
> -100M
> Image resized.
>
> Step 3,
> # /opt/qemu-git-arm/bin/qemu-img info /home/lijun/Work/tmp/shrink.qcow2
> image: /home/lijun/Work/tmp/shrink.qcow2
> file format: qcow2
> virtual size: 1.9G (2042626048 bytes)
> disk size: 1.9G
> cluster_size: 65536
> Format specific information:
> compat: 1.1
> lazy refcounts: false
> corrupt: false
>
> Step 4,
> # /opt/qemu-git-arm/bin/qemu-img check /home/lijun/Work/tmp/shrink.qcow2
> No errors were found on the image.
> 31005/31168 = 99.48% allocated, 0.79% fragmented, 0.00% compressed clusters
> Image end offset: 2033844224
>
> As above show, in step 1, "disk size" and "virtual size" are all 2.0G.
> After Step 3, "disk size" and "virtual size" are all 1.9G.
>
> BTW, above is also a simple testing. I will submit a test case for
> qemu-iotests later. But I am not so familar with howto write qemu-iotests now.
>
> In file block/qcow2.c, just using ftruncate to fix host cluster leak.
>
> In file block/qcow2-cluster.c, just re-copy qcow2_grow_l1_table to
> realize qcow2_shrink_l1_and_l2_table.
>
> In file block/qcow2-refcount.c, also update the realization to handle
> self-describing
> refcount blocks in function update_refcount.
>
> Thanks.
>
>
> Jun Li (2):
> qcow2: Add qcow2_shrink_l1_and_l2_table for qcow2 shrinking
> qcow2: add update refcount table realization for update_refcount
>
> block/qcow2-cluster.c | 173
> +++++++++++++++++++++++++++++++++++++++++++++++++
> block/qcow2-refcount.c | 44 +++++++++++++
> block/qcow2.c | 40 ++++++++++--
> block/qcow2.h | 2 +
> 4 files changed, 255 insertions(+), 4 deletions(-)
>
> --
> 1.9.3
>