Dave Chinner [off-list ref] wrote:

	st_blksize		- file block size
	st_alloc_blksize	- allocation block size/alignment
	st_small_io_size	- IO size/alignment that avoids
				  filesystem/page cache RMW
	st_preferred_io_size	- preferred IO size for general
				  usage.
	st_large_io_size	- IO size/alignment for high
				  bandwidth sequential IO

What is st_blksize here?  Is it directly comparable (if such a thing is
possible) to st_blksize in struct stat?  Or does st_preferred_io_size map to
the current st_blksize and your st_blksize map to actual media block size (and
if so, is that the same as st_alloc_blksize?  - I presume st_alloc_blksize
must be a multiple of the media block size).

David