Re: [Qemu-devel] [PATCH 12/12] Add disk_size field to BlockDriverState structure

[Fam Zheng <famcool@gmail.com>]

Is there any difference between bdrv_getlength and
bdrv_get_allocated_file_size for bs-file? If not, I can simplify it by
reusing it in two raw devices.

On Sun, Jun 19, 2011 at 2:35 AM, Stefan Hajnoczi <stefanha@gmail.com> wrote:
> On Sat, Jun 4, 2011 at 1:44 AM, Fam Zheng <famcool@gmail.com> wrote:
>> The `qemu-img info` results for mono flat image are no longer
>> accurate, as the "disk size" was the length of bs->file, which is not
>> the case for multi file images (such as vmdk images with multiple
>> files).
>> The new field disk_size in BlockDriverState can be used by block
>> driver to tell the exact disk size of block image (only valid if the
>> field is set to non-zero).
>>
>> Signed-off-by: Fam Zheng <famcool@gmail.com>
>> ---
>>  block/vmdk.c |    1 +
>>  block_int.h  |    1 +
>>  qemu-img.c   |    6 +++++-
>>  3 files changed, 7 insertions(+), 1 deletions(-)
>
> Instead of introducing a variable please add a new BlockDriver
> .bdrv_get_allocated_file_size() function pointer and move
> get_allocated_file_size() from qemu-img.c into block/raw-posix.c and
> block/raw-win32.c.
>
> qemu-img.c should call bdrv_get_allocated_file_size() and
> bdrv_get_allocated_file_size() could look like this:
>
> int bdrv_get_allocated_file_size(BlockDriverState *bs, int64_t *size)
> {
>    BlockDriver *drv = bs->drv;
>
>    if (!drv) {
>        return -ENOMEDIUM;
>    }
>
>    if (drv->bdrv_get_allocated_file_size) {
>        return drv->bdrv_get_allocated_file_size(bs, size);
>    }
>
>    if (bs->file) {
>        return bdrv_get_allocated_file_size(bs->file, size);
>    }
>    return -ENOTSUP;
> }
>
>> @@ -607,6 +607,7 @@ static int vmdk_open_desc_file(BlockDriverState
>> *bs, int flags)
>>     extent = s->extents;
>>     vmdk_parse_extents(buf, s->extents, bs->file->filename);
>>     bs->total_sectors = extent->sectors;
>> +    bs->disk_size = bdrv_getlength(bs->file) + bdrv_getlength(extent->file);
>
> This should call bdrv_get_allocated_file_size() so add together the
> actually allocated amount, not what bdrv_getlength() returns.
>
> Stefan
>



-- 
Best regards!
Fam Zheng