Il 12/11/2012 20:12, Charles Arnold ha scritto:
> Ping?
>
> Any thoughts on whether this is acceptable?
I would like to know what is done by other platforms. Stefano, any idea
about XenServer?
Paolo
> - Charles
>
>>>> On 10/30/2012 at 08:59 PM, in message <50a0e561.5b74.009...@suse.com>,
>>>> Charles
> Arnold wrote:
>> The VHD specification allows for up to a 2 TB disk size. The current
>> implementation in qemu emulates EIDE and ATA-2 hardware which only allows
>> for up to 127 GB. This disk size limitation can be overridden by allowing
>> up to 255 heads instead of the normal 4 bit limitation of 16. Doing so
>> allows disk images to be created of up to nearly 2 TB. This change does
>> not violate the VHD format specification nor does it change how smaller
>> disks (ie, <=127GB) are defined.
>>
>> Signed-off-by: Charles Arnold <carn...@suse.com>
>>
>> diff --git a/block/vpc.c b/block/vpc.c
>> index b6bf52f..0c2eaf8 100644
>> --- a/block/vpc.c
>> +++ b/block/vpc.c
>> @@ -198,7 +198,8 @@ static int vpc_open(BlockDriverState *bs, int flags)
>> bs->total_sectors = (int64_t)
>> be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
>>
>> - if (bs->total_sectors >= 65535 * 16 * 255) {
>> + /* Allow a maximum disk size of approximately 2 TB */
>> + if (bs->total_sectors >= 65535LL * 255 * 255) {qemu-devel@nongnu.org
>> err = -EFBIG;
>> goto fail;
>> }
>> @@ -524,19 +525,27 @@ static coroutine_fn int vpc_co_write(BlockDriverState
>> *bs, int64_t sector_num,
>> * Note that the geometry doesn't always exactly match total_sectors but
>> * may round it down.
>> *
>> - * Returns 0 on success, -EFBIG if the size is larger than 127 GB
>> + * Returns 0 on success, -EFBIG if the size is larger than ~2 TB. Override
>> + * the hardware EIDE and ATA-2 limit of 16 heads (max disk size of 127 GB)
>> + * and instead allow up to 255 heads.
>> */
>> static int calculate_geometry(int64_t total_sectors, uint16_t* cyls,
>> uint8_t* heads, uint8_t* secs_per_cyl)
>> {
>> uint32_t cyls_times_heads;
>>
>> - if (total_sectors > 65535 * 16 * 255)
>> + /* Allow a maximum disk size of approximately 2 TB */
>> + if (total_sectors > 65535LL * 255 * 255) {
>> return -EFBIG;
>> + }
>>
>> if (total_sectors > 65535 * 16 * 63) {
>> *secs_per_cyl = 255;
>> - *heads = 16;
>> + if (total_sectors > 65535 * 16 * 255) {
>> + *heads = 255;
>> + } else {
>> + *heads = 16;
>> + }
>> cyls_times_heads = total_sectors / *secs_per_cyl;
>> } else {
>> *secs_per_cyl = 17;
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