On Wed, May 19, 2021 at 04:57:16PM -0700, Darrick J. Wong wrote:

From: Darrick J. Wong <djwong@kernel.org>

This program fails on filesystems where the stat() block size isn't a
strict power of two because it foolishly feeds that to posix_memalign to
allocate an aligned memory buffer for directio.  posix_memalign requires
the alignment value to be a power of two, so generic/586 fails.

The system page size generally works well for directio buffers, so use
that instead.

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>