svn commit: r334511 - in head/sys/fs: nfs nfsclient

[Rick Macklem]

Author: rmacklem
Date: Sat Jun  2 00:11:26 2018
New Revision: 334511
URL: https://svnweb.freebsd.org/changeset/base/334511

Log:
  Fix the default number of threads for Flex File layout pNFS client I/O.
  
  The intent was that the default would be based on number of CPUs, but the
  code disabled using taskqueue() by default.
  This code is only executed when mounting a NFSv4.1 server that supports the
  Flexible File layout for pNFS and, since such servers are rare, this change
  shouldn't result in a POLA violation.
  (The FreeBSD pNFS server is still a project and the only other one that
   uses Flexible File layout is being developed by Primary Data and I don't
   know if they have even shipped any to customers yet.)
  Found while testing the pNFS server.

Modified:
  head/sys/fs/nfs/nfs_commonport.c
  head/sys/fs/nfsclient/nfs_clrpcops.c

Modified: head/sys/fs/nfs/nfs_commonport.c
==============================================================================
--- head/sys/fs/nfs/nfs_commonport.c	Sat Jun  2 00:02:27 2018	(r334510)
+++ head/sys/fs/nfs/nfs_commonport.c	Sat Jun  2 00:11:26 2018	(r334511)
@@ -90,7 +90,7 @@ SYSCTL_INT(_vfs_nfs, OID_AUTO, debuglevel, CTLFLAG_RW,
     0, "Debug level for NFS client");
 SYSCTL_INT(_vfs_nfs, OID_AUTO, userhashsize, CTLFLAG_RDTUN, &nfsrv_lughashsize,
     0, "Size of hash tables for uid/name mapping");
-int nfs_pnfsiothreads = 0;
+int nfs_pnfsiothreads = -1;
 SYSCTL_INT(_vfs_nfs, OID_AUTO, pnfsiothreads, CTLFLAG_RW, &nfs_pnfsiothreads,
     0, "Number of pNFS mirror I/O threads");
 
@@ -723,6 +723,8 @@ nfs_pnfsio(task_fn_t *func, void *context)
 	pio = (struct pnfsio *)context;
 	if (pnfsioq == NULL) {
 		if (nfs_pnfsiothreads == 0)
+			return (EPERM);
+		if (nfs_pnfsiothreads < 0)
 			nfs_pnfsiothreads = mp_ncpus * 4;
 		pnfsioq = taskqueue_create("pnfsioq", M_WAITOK,
 		    taskqueue_thread_enqueue, &pnfsioq);

Modified: head/sys/fs/nfsclient/nfs_clrpcops.c
==============================================================================
--- head/sys/fs/nfsclient/nfs_clrpcops.c	Sat Jun  2 00:02:27 2018	(r334510)
+++ head/sys/fs/nfsclient/nfs_clrpcops.c	Sat Jun  2 00:11:26 2018	(r334511)
@@ -6436,7 +6436,7 @@ nfsio_writedsmir(vnode_t vp, int *iomode, int *must_co
 	drpc->p = p;
 	drpc->inprog = 0;
 	ret = EIO;
-	if (nfs_pnfsiothreads > 0) {
+	if (nfs_pnfsiothreads != 0) {
 		ret = nfs_pnfsio(start_writedsmir, drpc);
 		NFSCL_DEBUG(4, "nfsio_writedsmir: nfs_pnfsio=%d\n", ret);
 	}
@@ -6615,7 +6615,7 @@ nfsio_commitds(vnode_t vp, uint64_t offset, int cnt, s
 	drpc->p = p;
 	drpc->inprog = 0;
 	ret = EIO;
-	if (nfs_pnfsiothreads > 0) {
+	if (nfs_pnfsiothreads != 0) {
 		ret = nfs_pnfsio(start_commitds, drpc);
 		NFSCL_DEBUG(4, "nfsio_commitds: nfs_pnfsio=%d\n", ret);
 	}