On Thu, 30 Jan 2014, James Bottomley wrote: > Why is this? the whole reason for CONFIG_LBDAF is supposed to be to > allow 64 bit offsets for block devices on 32 bit. It sounds like > there's somewhere not using sector_t ... or using it wrongly which needs > fixing. The page cache uses unsigned long as a page index. Therefore, if unsigned long is 32-bit, the block device may have at most 2^32-1 pages. > > On 32-bit architectures, we must limit block device size to > > PAGE_SIZE*(2^32-1). > > So you're saying CONFIG_LBDAF can never work, why? > > James CONFIG_LBDAF works, but it doesn't allow unlimited capacity: on x86, without CONFIG_LBDAF, the limit is 2TiB. With CONFIG_LBDAF, the limit is 16TiB (4096*2^32). Mikulas -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
