On 21 Sep 2022, at 14:13, Alan Maxwell wrote:
I am reporting an issue, not a fault or bugreport.
NFS client : Redhat 7 kernel: 3.10.0-1160.71.1.el7.x86_64.
The issue lies with the feature that nfs client that: if an nfs server
rejects an unmapped uid or gid, then the client will automatically
switch back to using the idmapper.
Our particular configuration of nfsv4 server and client are based on
using numeric uidNumber and gidNumber communication. The nfs server
we are using , OneFS (Dell/EMC/Isilon) has a setting explicitly for
this use: "Do not send names". We have this set and our testing
showed working 100% with our nfs client. The main driver for us using
this feature is that our uid's are numeric. That causes issues with
commands like chown and apparently NFS setattr. Once we realized
that, we set the numeric setting and everything worked as planned.
Our problem with the feature comes due to a simple mistake made by an
Admin:
chgrp groupnotvalid file
When the admin issued a chgrp, but that group does not exist in the
directory service for the NFS server, the NFS server rejected the
change. Then the feature kicked in that "client will automatically
switch back to using the idmapper. " Which did make changes, the
/proc/self/mountstats showing the caps=0x7fff instead of 0xffff.
The only solution to get the mount to work as originally configured is
to umount/mount the share.
Bottom line: Our environment can not support idmapping. Having the
feature to disable it and that disable be forceful and not something
the kernel can decide to re-enable.
We would envision that if an invalid chown/chgrp were issued, to
simply return an error, report that the chown/chgrp were not applied
and simply leave the nfsmount as is.
Alan Maxwell | Sr. System Programmer | Platinum Infrastructure|20
FedEx Pkwy 1st Fl Vert,Collierville, TN 38017
Seems like a server bug to me -- if you want to set a numeric group on a
file, the server doesn't need to "look up" the group to see if it
exists, it
should just set the value on the underlying filesystem.
What the server is signaling by sending back NFS4ERR_BADOWNER is that it
actually /is/ doing id mapping.
Why doesn't OneFS just set the value when told "Do not send names"?
Ben
