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Re: [Qemu-devel] [PATCH v2 3/5] block/vpc: make calculate_geometry spec
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] [PATCH v2 3/5] block/vpc: make calculate_geometry spec conform |
Date: |
Tue, 03 Mar 2015 10:05:11 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 |
On 2015-03-03 at 05:41, Peter Lieven wrote:
The VHD spec [1] allows for total_sectors of 65535 x 16 x 255 (~127GB)
represented by a CHS geometry. If total_sectors is greater
than 65535 x 16 x 255 this geometry is set as a maximum.
Qemu, Hyper-V and disk2vhd use this special geometry as an indicator
to use the image current size from the footer as disk size.
This patch changes vpc_create to effectively calculate a CxHxS geometry
for the given image size if possible while rounding up if necessary.
If the image size is to big to be represented in CHS we set the maximum
"too big" (as it was in v1) was correct, no need to make it wrong. :-)
and write the exact requested image size into the footer.
This partly reverts commit 258d2edb, but leaves support for >127G disks
intact.
[1]
http://download.microsoft.com/download/f/f/e/ffef50a5-07dd-4cf8-aaa3-442c0673a029/Virtual%20Hard%20Disk%20Format%20Spec_10_18_06.doc
Signed-off-by: Peter Lieven <address@hidden>
---
block/vpc.c | 41 ++++++++++++++++++++++-------------------
1 file changed, 22 insertions(+), 19 deletions(-)
With s/to big/too big/:
Reviewed-by: Max Reitz <address@hidden>
- [Qemu-devel] [PATCH v2 0/5] block/vpc optimizations, Peter Lieven, 2015/03/03
- [Qemu-devel] [PATCH v2 4/5] block/vpc: rename footer->size -> footer->current_size, Peter Lieven, 2015/03/03
- [Qemu-devel] [PATCH v2 3/5] block/vpc: make calculate_geometry spec conform, Peter Lieven, 2015/03/03
- Re: [Qemu-devel] [PATCH v2 3/5] block/vpc: make calculate_geometry spec conform,
Max Reitz <=
- [Qemu-devel] [PATCH v2 1/5] block/vpc: optimize vpc_co_get_block_status, Peter Lieven, 2015/03/03
- [Qemu-devel] [PATCH v2 2/5] vpc: Ignore geometry for large images, Peter Lieven, 2015/03/03
- [Qemu-devel] [PATCH v2 5/5] block/vpc: remove disabled code from get_sector_offset, Peter Lieven, 2015/03/03
- Re: [Qemu-devel] [PATCH v2 0/5] block/vpc optimizations, Max Reitz, 2015/03/03