Add a timeout for the negative name cache entries in the NFS client.

This avoids a bogus negative name cache entry from persisting forever
when another client creates an entry with the same name within the
same NFS server time of day clock tick. The mount option negnametimeo
can be used to override the default timeout interval on a
per-mount-point basis. Setting negnametimeo to 0 disables negative
name caching for the mount point.
I also fixed one obvious typo where args.timeo should be
args.maxgrouplist.

Submitted by:	jhb (earlier version)
Reviewed by:	jhb
MFC after:	2 weeks

1 files changed, 18 insertions, 6 deletions

diff --git a/sys/nfsclient/nfs_vfsops.c b/sys/nfsclient/nfs_vfsops.c
index 2346d41..72ca2ce 100644
--- a/sys/nfsclient/nfs_vfsops.c
+++ b/sys/nfsclient/nfs_vfsops.c
@@ -114,7 +114,7 @@ static void	nfs_decode_args(struct mount *mp, struct nfsmount *nmp,
 		    struct nfs_args *argp, const char *hostname);
 static int	mountnfs(struct nfs_args *, struct mount *,
 		    struct sockaddr *, char *, struct vnode **,
-		    struct ucred *cred);
+		    struct ucred *cred, int);
 static vfs_mount_t nfs_mount;
 static vfs_cmount_t nfs_cmount;
 static vfs_unmount_t nfs_unmount;
@@ -551,7 +551,7 @@ nfs_mountdiskless(char *path,
 
 	nam = sodupsockaddr((struct sockaddr *)sin, M_WAITOK);
 	if ((error = mountnfs(args, mp, nam, path, vpp,
-	    td->td_ucred)) != 0) {
+	    td->td_ucred, NFS_DEFAULT_NEGNAMETIMEO)) != 0) {
 		printf("nfs_mountroot: mount %s on /: %d\n", path, error);
 		return (error);
 	}
@@ -778,7 +778,7 @@ static const char *nfs_opts[] = { "from", "nfs_args",
     "readdirsize", "soft", "hard", "mntudp", "tcp", "udp", "wsize", "rsize",
     "retrans", "acregmin", "acregmax", "acdirmin", "acdirmax", 
     "deadthresh", "hostname", "timeout", "addr", "fh", "nfsv3", "sec",
-    "maxgroups", "principal",
+    "maxgroups", "principal", "negnametimeo",
     NULL };
 
 /*
@@ -827,6 +827,7 @@ nfs_mount(struct mount *mp)
 	size_t len;
 	u_char nfh[NFSX_V3FHMAX];
 	char *opt;
+	int negnametimeo = NFS_DEFAULT_NEGNAMETIMEO;
 
 	has_nfs_args_opt = 0;
 	has_addr_opt = 0;
@@ -1029,7 +1030,7 @@ nfs_mount(struct mount *mp)
 	}
 	if (vfs_getopt(mp->mnt_optnew, "maxgroups", (void **)&opt, NULL) == 0) {
 		ret = sscanf(opt, "%d", &args.maxgrouplist);
-		if (ret != 1 || args.timeo <= 0) {
+		if (ret != 1 || args.maxgrouplist <= 0) {
 			vfs_mount_error(mp, "illegal maxgroups: %s",
 			    opt);
 			error = EINVAL;
@@ -1037,6 +1038,16 @@ nfs_mount(struct mount *mp)
 		}
 		args.flags |= NFSMNT_MAXGRPS;
 	}
+	if (vfs_getopt(mp->mnt_optnew, "negnametimeo", (void **)&opt, NULL)
+	    == 0) {
+		ret = sscanf(opt, "%d", &negnametimeo);
+		if (ret != 1 || negnametimeo < 0) {
+			vfs_mount_error(mp, "illegal negnametimeo: %s",
+			    opt);
+			error = EINVAL;
+			goto out;
+		}
+	}
 	if (vfs_getopt(mp->mnt_optnew, "addr", (void **)&args.addr,
 		&args.addrlen) == 0) {
 		has_addr_opt = 1;
@@ -1125,7 +1136,7 @@ nfs_mount(struct mount *mp)
 		}
 	}
 	error = mountnfs(&args, mp, nam, args.hostname, &vp,
-	    curthread->td_ucred);
+	    curthread->td_ucred, negnametimeo);
 out:
 	if (!error) {
 		MNT_ILOCK(mp);
@@ -1167,7 +1178,7 @@ nfs_cmount(struct mntarg *ma, void *data, int flags)
  */
 static int
 mountnfs(struct nfs_args *argp, struct mount *mp, struct sockaddr *nam,
-    char *hst, struct vnode **vpp, struct ucred *cred)
+    char *hst, struct vnode **vpp, struct ucred *cred, int negnametimeo)
 {
 	struct nfsmount *nmp;
 	struct nfsnode *np;
@@ -1217,6 +1228,7 @@ mountnfs(struct nfs_args *argp, struct mount *mp, struct sockaddr *nam,
 	nmp->nm_numgrps = NFS_MAXGRPS;
 	nmp->nm_readahead = NFS_DEFRAHEAD;
 	nmp->nm_deadthresh = NFS_MAXDEADTHRESH;
+	nmp->nm_negnametimeo = negnametimeo;
 	nmp->nm_tprintf_delay = nfs_tprintf_delay;
 	if (nmp->nm_tprintf_delay < 0)
 		nmp->nm_tprintf_delay = 0;