HP-UX 11.23 Automount / NFS mount fails to ZFS filler

[RonMarch]

Does anyone know if there is a fix to this issue other than upgrade to hp-ux 11i v3 or use NFS version2?  Have a client that is locked into hp-ux version 11.23 for at least another year until software port is completed.  Thanks in advance.

Description
   Known bug in HP-UX NFS client prior to HP-UX 11.31:  NFS client doesn't properly handle nanosecond timestamps on files shared via NFS V3 from a ZFS back-end filesystem.
Since 11.31 only runs on HP server class machines, we are unable to work with ZFS filesystems on older HP-UX boxes without dropping back to NFS V2, which has filesize limitations that are unacceptable (2GB max) as well as much poorer performance.
Suggest a new ZFS property:  timegranularity
whose default value is 'nanoseconds' but can be set to 'seconds'.
When set to 'seconds' the ZFS filesystem will only report time values down to 'seconds' granularity and NFS server should zero the nanoseconds portion of the nfstime3 structure, thereby solving the interoperability problem with HP-UX.
Frequency
   Always
Regression
   No
Steps to Reproduce
   See Bug ID 6538387:
http://bugs.opensolaris.org/view_bug.do?bug_id=6538387
Expected Result
   Actions on files should proceed as expected, and operations should complete.
Actual Result
   The client system hangs.  If you snoop the connection you see an undending sequence of:
hp_client -> solaris_server     NFS C SETATTR3 FH=597F
    solaris_server -> hp_client NFS R SETATTR3 Update synch mismatch
hp_client -> solaris_server     NFS C SETATTR3 FH=A57F
    solaris_server -> hp_client NFS R SETATTR3 Update synch mismatch
hp_client -> solaris_server     NFS C GETATTR3 FH=597F
    solaris_server -> hp_client NFS R GETATTR3 OK
hp_client -> solaris_server     NFS C GETATTR3 FH=A57F
    solaris_server -> hp_client NFS R GETATTR3 OK
Error Message(s)
   None.  System hangs.
Test Case
  
Workaround
   Use NFS V2, which doesn't support nanosecond time on files.
Submitter wants to work on bug
   No
Additional configuration information
   All versions of Solaris/OpenSolaris with ZFS filesystems.

[Dave Olker]

Hi Ron,

What NFS kernel patch level are you running on the 11.23 system?  I know we made an attempt at fixing this problem back in QXCR1000593901:

PROBLEM

There is an issue between the granularity of file creation times on the client and the server. For HP-UX 11i v1 and HP-UX 11i v2, time is stored with microsecond granularity. Other server implementations use nanosecond granularity with NFS V3 (for NFS V2 only microsecond granularity is used). This difference in granularity causes an infinite loop in the client's code since it waits for its time value to match that of the server.

FIX
Modified the NFS V3 code to store file times with nanosecond granularity.

Fixed in these patches:
11.11 ONC/NFS patch PHNE_37568
11.23 NFS patch PHNE_37851

The 11.23 fix originally shipped in PHNE_37851:

PHNE_37851:
( QX:QXCR1000593901 SR:8606498273 CR:JAGag50178 )
A process trying to truncate a file stops responding with some NFS server implementations.

That patch shipped back in May 2008.  It's since been superseded a number of times.  The latest patch is PHNE_41975.  Have you tried installing PHNE_41975 and its dependent patches to see if this resolves the problem?

Regards,

Dave