On Sat, Apr 9, 2011 at 5:51 PM, Lyu Mitnick <mitnick....@gmail.com> wrote: > Hell all, > I have take a look of block/vpc.c and meet a question in vpc_create(). At > the line > 550, the code is: > total_sectors = options->value.n / 512; > I am wondering whether the size between total_sectors * 512 > and options->value.n > would be discard.
Yes, it rounds down. This reflects the assumption that a block device cannot be addressed below 512 byte sectors. Because of this block devices size must be a multiple of 512 bytes. I think a reasonable protection would be to have block.c:bdrv_create() fail if size is not a multiple of BDRV_SECTOR_SIZE. This way other image formats are protected too. Stefan
