nfs/localio: avoid issuing misaligned IO using O_DIRECT

Browse source

[ Upstream commit 25ba2b84c3 ]

Add nfsd_file_dio_alignment and use it to avoid issuing misaligned IO
using O_DIRECT. Any misaligned DIO falls back to using buffered IO.

Because misaligned DIO is now handled safely, remove the nfs modparam
'localio_O_DIRECT_semantics' that was added to require users opt-in to
the requirement that all O_DIRECT be properly DIO-aligned.

Also, introduce nfs_iov_iter_aligned_bvec() which is a variant of
iov_iter_aligned_bvec() that also verifies the offset associated with
an iov_iter is DIO-aligned.  NOTE: in a parallel effort,
iov_iter_aligned_bvec() is being removed along with
iov_iter_is_aligned().

Lastly, add pr_info_ratelimited if underlying filesystem returns
-EINVAL because it was made to try O_DIRECT for IO that is not
DIO-aligned (shouldn't happen, so its best to be louder if it does).

Fixes: 3feec68563 ("nfs/localio: add direct IO enablement with sync and async IO support")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Mike Snitzer 2025-09-19 10:36:26 -04:00 • committed by Greg Kroah-Hartman

parent 45e0e1ec14

commit a97bf1a0cd

3 changed files with 68 additions and 10 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

65

fs/nfs/localio.c

View file

11

fs/nfsd/localio.c

View file

2

include/linux/nfslocalio.h

View file