On Wed, May 01, 2024 at 04:15:33PM -0700, Jeremy Bongio wrote:

From: Jeremy Bongio <redacted>

ext4 and block fops would both failover to syncronous, buffered writes if
the direct IO results in a short write where only a portion of the request
was completed.

This patch changes the behavior to simply return the number of bytes
written if the direct write is short.

Please don't combine ext4 and block changes in a single patch.  Please
also explain why you want to change things.

AFAIK this is simply the historic behavior of the old direct I/O code
that's been around forever.  I think the XFS semantics make a lot more
sense, but people might rely on this one way or another.