On Wed, Oct 18, 2023 at 10:24:18AM -0400, Benjamin Coddington wrote:

On 18 Oct 2023, at 9:33, Jeff Layton wrote:

quoted

On Wed, 2023-10-18 at 08:56 -0400, Chuck Lever wrote:

quoted

On Tue, Oct 17, 2023 at 05:30:44PM -0400, Benjamin Coddington wrote:

quoted

Expose a per-mount knob in sysfs to set the READDIR requested attributes
for a non-plus READDIR request.

For example:

  echo 0x800 0x800000 0x0 > /sys/fs/nfs/0\:57/v4_readdir_attrs

.. will revert the client to only request rdattr_error and
mounted_on_fileid for any non "plus" READDIR, as before the patch
preceeding this one in this series.  This provides existing installations
an option to fix a potential performance regression that may occur after
NFS clients update to request additional default READDIR attributes.

Signed-off-by: Benjamin Coddington <redacted>
---
 fs/nfs/client.c           |  2 +
 fs/nfs/nfs4client.c       |  4 ++
 fs/nfs/nfs4proc.c         |  1 +
 fs/nfs/nfs4xdr.c          |  7 ++--
 fs/nfs/sysfs.c            | 81 +++++++++++++++++++++++++++++++++++++++
 include/linux/nfs_fs_sb.h |  1 +
 include/linux/nfs_xdr.h   |  1 +
 7 files changed, 93 insertions(+), 4 deletions(-)

Admittedly, it would be much easier for humans to use if the API was
based on the symbolic names of the bits rather than a triplet of raw
hexadecimal values.

This isn't aiming to be an ease-of-use interface.  This is tinkering with
the innards of the client.  If you're doing this, you better know how to
convert between bases, because you're going to need that and more.

If we want to make it nice, patches to nfsctl can follow.

I don't see a reason this shouldn't be easier to use, especially
since mistakes in setting these bits have consequences. There are
currently 82 of them, after all.

But, OK, the polish can be applied by a user space tool.


-- 
Chuck Lever