On 7/24/25 4:04 AM, Hannes Reinecke wrote:
While there are no real checks on the physical blocksize (all what matters to the block layer is the logical blocksize) I can't really see how a device can have a physical blocksize which is _not_ a multiple of the logical blocksize.
From SBC-5: ------------------------------------------------------------------------ Table 91 — LOGICAL BLOCKS PER PHYSICAL BLOCK EXPONENT field Code Description 0 One or more physical blocks per logical block (a) n > 0 2n logical blocks per physical block a The number of physical blocks per logical block is not reported. ------------------------------------------------------------------------ I think this means that the SCSI standards support physical blocks that are smaller than the logical block size. However, as far as I know the Linux kernel does not try to determine the physical block size in this case. As one can see in drivers/scsi/sd.c LBPPBE == 0 is treated as one physical block per logical block: /* Logical blocks per physical block exponent */ sdkp->physical_block_size = (1 << (buffer[13] & 0xf)) * sector_size; Bart.
