[Linux-cluster] HP-UX NFS client failures to a NFS cluster when GFS is the backing filesystem

[Dan Goetzman]

Problem: HP-UX NFS client failures to a NFS cluster when GFS is the 
backing filesystem.

$ cp any_file /path/to/nfs/server/new_file
cp: cannot create /path/to/nfs/server/new_file: Permission denied
$ ls -l
---------- 1 owner group 0 Jan 17 10:01 new_file
$

 Note: Permission denied error, and the file is created, 0 size with no 
permissions bits. Tested on CentOS 5.

My attempt to gather data on the problem:

A wireshark trace shows the HP-UX client make a NFS RPC CREATE 
(UNCHECKED, MODE=0) call and the server returns NFS3ERR_NOACCES. As this 
only happens when the server side filesystem is GFS and not when using 
ext3, I moved to the server side...

Looking at the server side it appears that nfsd calls vfs_create OK, but 
a later call to nfsd_setattr (I assume set the actual file permissions) 
fails. Attempting to trace what nfsd_setattr is doing, it seems to 
eventually call gfs_setattr and then generic_permission. The call to 
generic_permission fails with -EACCESS. Apparently due to owner not 
having any access mode bits set?

I am not a kernel type. I looked and ext3_setattr does not seem to use 
generic_permission.
This problem would seem to make using GFS to build a clustered NFS 
server a problem (if you have HP-UX NFS clients!).
Anyone know why this is a problem when using GFS?

-Dan Goetzman

Note: I read linux-cluster in digest mode.