Post r230394, the Lookup RPC counts for both NFS clients increased

significantly. Upon investigation this was caused by name cache
misses for lookups of "..". For name cache entries for non-".."
directories, the cache entry serves double duty. It maps both the
named directory plus ".." for the parent of the directory. As such,
two ctime values (one for each of the directory and its parent) need
to be saved in the name cache entry.
This patch adds an entry for ctime of the parent directory to the
name cache. It also adds an additional uma zone for large entries
with this time value, in order to minimize memory wastage.
As well, it fixes a couple of cases where the mtime of the parent
directory was being saved instead of ctime for positive name cache
entries. With this patch, Lookup RPC counts return to values similar
to pre-r230394 kernels.

Reported by:	bde
Discussed with:	kib
Reviewed by:	jhb
MFC after:	2 weeks

1 files changed, 15 insertions, 11 deletions

diff --git a/sys/nfsclient/nfs_vnops.c b/sys/nfsclient/nfs_vnops.c
index 241af51..191ed40 100644
--- a/sys/nfsclient/nfs_vnops.c
+++ b/sys/nfsclient/nfs_vnops.c
@@ -912,7 +912,7 @@ nfs_lookup(struct vop_lookup_args *ap)
 	struct vnode *dvp = ap->a_dvp;
 	struct vnode **vpp = ap->a_vpp;
 	struct mount *mp = dvp->v_mount;
-	struct vattr vattr;
+	struct vattr dvattr, vattr;
 	struct timespec nctime;
 	int flags = cnp->cn_flags;
 	struct vnode *newvp;
@@ -1129,7 +1129,7 @@ nfs_lookup(struct vop_lookup_args *ap)
 	}
 	if (v3) {
 		nfsm_postop_attr_va(newvp, attrflag, &vattr);
-		nfsm_postop_attr(dvp, dattrflag);
+		nfsm_postop_attr_va(dvp, dattrflag, &dvattr);
 	} else {
 		nfsm_loadattr(newvp, &vattr);
 		attrflag = 1;
@@ -1137,9 +1137,10 @@ nfs_lookup(struct vop_lookup_args *ap)
 	if (cnp->cn_nameiop != LOOKUP && (flags & ISLASTCN))
 		cnp->cn_flags |= SAVENAME;
 	if ((cnp->cn_flags & MAKEENTRY) &&
-	    (cnp->cn_nameiop != DELETE || !(flags & ISLASTCN)) && attrflag) {
-		cache_enter_time(dvp, newvp, cnp, &vattr.va_ctime);
-	}
+	    (cnp->cn_nameiop != DELETE || !(flags & ISLASTCN)) &&
+	    attrflag != 0 && (newvp->v_type != VDIR || dattrflag != 0))
+		cache_enter_time(dvp, newvp, cnp, &vattr.va_ctime,
+		    newvp->v_type != VDIR ? NULL : &dvattr.va_ctime);
 	*vpp = newvp;
 	m_freem(mrep);
 nfsmout:
@@ -1181,7 +1182,7 @@ nfsmout:
 			    &vattr.va_mtime, ==)) {
 				mtx_unlock(&np->n_mtx);
 				cache_enter_time(dvp, NULL, cnp,
-				    &vattr.va_mtime);
+				    &vattr.va_mtime, NULL);
 			} else
 				mtx_unlock(&np->n_mtx);
 		}
@@ -2463,11 +2464,11 @@ nfs_readdirplusrpc(struct vnode *vp, struct uio *uiop, struct ucred *cred)
 	nfsuint64 cookie;
 	struct nfsmount *nmp = VFSTONFS(vp->v_mount);
 	struct nfsnode *dnp = VTONFS(vp), *np;
-	struct vattr vattr;
+	struct vattr vattr, dvattr;
 	nfsfh_t *fhp;
 	u_quad_t fileno;
 	int error = 0, tlen, more_dirs = 1, blksiz = 0, doit, bigenough = 1, i;
-	int attrflag, fhsize;
+	int attrflag, dattrflag, fhsize;
 
 #ifndef nolint
 	dp = NULL;
@@ -2513,7 +2514,7 @@ nfs_readdirplusrpc(struct vnode *vp, struct uio *uiop, struct ucred *cred)
 		*tl++ = txdr_unsigned(nmp->nm_readdirsize);
 		*tl = txdr_unsigned(nmp->nm_rsize);
 		nfsm_request(vp, NFSPROC_READDIRPLUS, uiop->uio_td, cred);
-		nfsm_postop_attr(vp, attrflag);
+		nfsm_postop_attr_va(vp, dattrflag, &dvattr);
 		if (error) {
 			m_freem(mrep);
 			goto nfsmout;
@@ -2649,8 +2650,11 @@ nfs_readdirplusrpc(struct vnode *vp, struct uio *uiop, struct ucred *cred)
 				md = mdsav2;
 				dp->d_type = IFTODT(VTTOIF(vattr.va_type));
 				ndp->ni_vp = newvp;
-			        cache_enter_time(ndp->ni_dvp, ndp->ni_vp, cnp,
-				    &vattr.va_ctime);
+				if (newvp->v_type != VDIR || dattrflag != 0)
+				    cache_enter_time(ndp->ni_dvp, ndp->ni_vp,
+					cnp, &vattr.va_ctime,
+					newvp->v_type != VDIR ? NULL :
+					&dvattr.va_ctime);
 			    }
 			} else {
 			    /* Just skip over the file handle */