svn commit: r317465 - head/sys/fs/nfsclient

[Rick Macklem]

Author: rmacklem
Date: Wed Apr 26 21:54:53 2017
New Revision: 317465
URL: https://svnweb.freebsd.org/changeset/base/317465

Log:
  Fix handling of a NFSv4.1 callback reply from the session cache.
  
  The nfsv4_seqsession() call returns NFSERR_REPLYFROMCACHE when it has a
  reply in the session, due to a requestor retry. The code erroneously
  assumed a return of 0 for this case. This patch fixes this and adds
  a KASSERT(). This would be an extremely rare occurrence. It was found
  during code inspection during the pNFS server development.
  
  MFC after:	2 weeks

Modified:
  head/sys/fs/nfsclient/nfs_clstate.c

Modified: head/sys/fs/nfsclient/nfs_clstate.c
==============================================================================
--- head/sys/fs/nfsclient/nfs_clstate.c	Wed Apr 26 20:21:05 2017	(r317464)
+++ head/sys/fs/nfsclient/nfs_clstate.c	Wed Apr 26 21:54:53 2017	(r317465)
@@ -3560,9 +3560,18 @@ nfscl_docb(struct nfsrv_descript *nd, NF
 				    tsep->nfsess_backslots);
 			}
 			NFSUNLOCKCLSTATE();
-			if (error == 0) {
+			if (error == 0 || error == NFSERR_REPLYFROMCACHE) {
 				gotseq_ok = 1;
 				if (rep != NULL) {
+					/*
+					 * Handle a reply for a retried
+					 * callback.  The reply will be
+					 * re-inserted in the session cache
+					 * by the nfsv4_seqsess_cacherep() call
+					 * after out:
+					 */
+					KASSERT(error == NFSERR_REPLYFROMCACHE,
+					    ("cbsequence: non-NULL rep"));
 					NFSCL_DEBUG(4, "Got cbretry\n");
 					m_freem(nd->nd_mreq);
 					nd->nd_mreq = rep;