From 9793c8195b66b2ccc42b2c2ddb59f26b97ce3d36 Mon Sep 17 00:00:00 2001
From: Matthew Dillon <dillon@dragonflybsd.org>
Date: Sun, 13 Mar 2005 22:17:40 +0000
Subject: [PATCH] Fix a couple of NFS client side caching snafus.  First, we
 have to update np->n_mtime if the file has not being modified locally,
 otherwise n_mtime becomes stale and both the dynamic cache timeout
 calculation breaks and stat() calls checking for the last modified time
 break.  This was causing indeterminant operation with make for obvious
 reasons.

The Second problem was that we were not checking for an attrstamp of 0
(indicating a timed out entry), resulting in another incorrect timeout
calculation.
---
 sys/vfs/nfs/nfs_subs.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/sys/vfs/nfs/nfs_subs.c b/sys/vfs/nfs/nfs_subs.c
index 582f44c222..aca2358144 100644
--- a/sys/vfs/nfs/nfs_subs.c
+++ b/sys/vfs/nfs/nfs_subs.c
@@ -35,7 +35,7 @@
  *
  *	@(#)nfs_subs.c  8.8 (Berkeley) 5/22/95
  * $FreeBSD: /repoman/r/ncvs/src/sys/nfsclient/nfs_subs.c,v 1.128 2004/04/14 23:23:55 peadar Exp $
- * $DragonFly: src/sys/vfs/nfs/nfs_subs.c,v 1.24 2004/12/17 00:18:28 dillon Exp $
+ * $DragonFly: src/sys/vfs/nfs/nfs_subs.c,v 1.25 2005/03/13 22:17:40 dillon Exp $
  */
 
 /*
@@ -1249,6 +1249,13 @@ nfs_loadattrcache(struct vnode **vpp, struct mbuf **mdp, caddr_t *dposp,
 			vp->v_ops = &vp->v_mount->mnt_vn_use_ops;
 		}
 		np->n_mtime = mtime.tv_sec;
+	} else if ((np->n_flag & NMODIFIED) == 0) {
+		/*
+		 * If we haven't modified the file locally update our notion
+		 * of the last-modified time based on the server's
+		 * information.
+		 */
+		np->n_mtime = mtime.tv_sec;
 	}
 	vap = &np->n_vattr;
 	vap->va_type = vtyp;
@@ -1356,7 +1363,7 @@ nfs_getattrcache(struct vnode *vp, struct vattr *vaper)
 	/*
 	 * Dynamic timeout based on how recently the file was modified.
 	 */
-	timeo = (time_second - np->n_mtime) / 10;
+	timeo = (get_approximate_time_t() - np->n_mtime) / 10;
 
 #ifdef NFS_ACDEBUG
 	if (nfs_acdebug>1)
@@ -1383,10 +1390,10 @@ nfs_getattrcache(struct vnode *vp, struct vattr *vaper)
 
 	if (nfs_acdebug)
 		printf("nfs_getattrcache: age = %d; final timeo = %d\n",
-			(time_second - np->n_attrstamp), timeo);
+			(int)(time_second - np->n_attrstamp), timeo);
 #endif
 
-	if ((time_second - np->n_attrstamp) >= timeo) {
+	if (np->n_attrstamp == 0 || (time_second - np->n_attrstamp) >= timeo) {
 		nfsstats.attrcache_misses++;
 		return (ENOENT);
 	}
-- 
2.11.4.GIT