--- vfs_mount.c.orig	Tue Feb  3 10:30:56 2004
+++ vfs_mount.c	Tue Feb  3 12:35:48 2004
@@ -111,8 +111,9 @@ static int	vfs_mountroot_ask(void);
 static int	vfs_mountroot_try(char *mountfrom);
 static int	vfs_nmount(struct thread *td, int fsflags, struct uio *fsopts);
 
-static int	usermount = 0;	/* if 1, non-root can mount fs. */
-SYSCTL_INT(_vfs, OID_AUTO, usermount, CTLFLAG_RW, &usermount, 0, "");
+static int	usermount = 0;
+SYSCTL_INT(_vfs, OID_AUTO, usermount, CTLFLAG_RW, &usermount, 0,
+    "Permit unprivileged users mount/unmount file systems");
 
 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
 
@@ -208,6 +209,25 @@ vfs_freeopts(struct vfsoptlist *opts)
 }
 
 /*
+ * Check if options are equal (with or without the "no" prefix).
+ */
+static int
+vfs_equalopts(const char *opt1, const char *opt2)
+{
+
+	/* "opt" vs. "opt" or "noopt" vs. "noopt" */
+	if (strcmp(opt1, opt2) == 0)
+		return (1);
+	/* "noopt" vs. "opt" */
+	if (strncmp(opt1, "no", 2) == 0 && strcmp(opt1 + 2, opt2) == 0)
+		return (1);
+	/* "opt" vs. "noopt" */
+	if (strncmp(opt2, "no", 2) == 0 && strcmp(opt1, opt2 + 2) == 0)
+		return (1);
+	return (0);
+}
+
+/*
  * If a mount option is specified several times,
  * (with or without the "no" prefix) only keep
  * the last occurence of it.
@@ -216,19 +236,11 @@ static void
 vfs_sanitizeopts(struct vfsoptlist *opts)
 {
 	struct vfsopt *opt, *opt2, *tmp;
-	int noopt;
 
 	TAILQ_FOREACH_REVERSE(opt, opts, vfsoptlist, link) {
-		if (strncmp(opt->name, "no", 2) == 0)
-			noopt = 1;
-		else
-			noopt = 0;
 		opt2 = TAILQ_PREV(opt, vfsoptlist, link);
 		while (opt2 != NULL) {
-			if (strcmp(opt2->name, opt->name) == 0 ||
-			    (noopt && strcmp(opt->name + 2, opt2->name) == 0) ||
-			    (!noopt && strncmp(opt2->name, "no", 2) == 0 &&
-			    strcmp(opt2->name + 2, opt->name) == 0)) {
+			if (vfs_equalopts(opt->name, opt2->name)) {
 				tmp = TAILQ_PREV(opt2, vfsoptlist, link);
 				vfs_freeopt(opts, opt2);
 				opt2 = tmp;
@@ -286,7 +298,7 @@ vfs_buildopts(struct uio *auio, struct v
 		} else {
 			error = copyin(auio->uio_iov[i].iov_base, opt->name,
 			    namelen);
-			if (error)
+			if (error != 0)
 				goto bad;
 		}
 		/* Ensure names are null-terminated strings. */
@@ -302,7 +314,7 @@ vfs_buildopts(struct uio *auio, struct v
 			} else {
 				error = copyin(auio->uio_iov[i + 1].iov_base,
 				    opt->value, optlen);
-				if (error)
+				if (error != 0)
 					goto bad;
 			}
 		}
@@ -395,7 +407,8 @@ nmount(td, uap)
 	auio.uio_iov = iov;
 	auio.uio_iovcnt = iovcnt;
 	auio.uio_segflg = UIO_USERSPACE;
-	if ((error = copyin(uap->iovp, iov, iovlen)))
+	error = copyin(uap->iovp, iov, iovlen);
+	if (error != 0)
 		goto finish;
 
 	for (i = 0; i < iovcnt; i++) {
@@ -548,7 +561,7 @@ vfs_nmount(struct thread *td, int fsflag
 	int error, fstypelen, fspathlen;
 
 	error = vfs_buildopts(fsoptions, &optlist);
-	if (error)
+	if (error != 0)
 		return (error);
 
 	/*
@@ -558,13 +571,13 @@ vfs_nmount(struct thread *td, int fsflag
 	 */
 	fstypelen = 0;
 	error = vfs_getopt(optlist, "fstype", (void **)&fstype, &fstypelen);
-	if (error || fstype[fstypelen - 1] != '\0') {
+	if (error != 0 || fstype[fstypelen - 1] != '\0') {
 		error = EINVAL;
 		goto bail;
 	}
 	fspathlen = 0;
 	error = vfs_getopt(optlist, "fspath", (void **)&fspath, &fspathlen);
-	if (error || fspath[fspathlen - 1] != '\0') {
+	if (error != 0 || fspath[fspathlen - 1] != '\0') {
 		error = EINVAL;
 		goto bail;
 	}
@@ -581,7 +594,7 @@ vfs_nmount(struct thread *td, int fsflag
 
 	error = vfs_domount(td, fstype, fspath, fsflags, optlist, 0);
 bail:
-	if (error)
+	if (error != 0)
 		vfs_freeopts(optlist);
 	return (error);
 }
@@ -679,34 +692,34 @@ vfs_domount(
 	if (strlen(fstype) >= MFSNAMELEN || strlen(fspath) >= MNAMELEN)
 		return (ENAMETOOLONG);
 
-	/* mount(2) is not permitted inside the jail. */
 	if (jailed(td->td_ucred))
 		return (EPERM);
-
 	if (usermount == 0) {
 		error = suser(td);
-		if (error)
+		if (error != 0)
 			return (error);
 	}
+
 	/*
 	 * Do not allow NFS export by non-root users.
 	 */
 	if (fsflags & MNT_EXPORTED) {
 		error = suser(td);
-		if (error)
+		if (error != 0)
 			return (error);
 	}
 	/*
-	 * Silently enforce MNT_NOSUID, MNT_NODEV and MNT_USER
-	 * for unprivileged users.
+	 * Silently enforce MNT_NOSUID, MNT_NODEV and MNT_USER for
+	 * unprivileged users.
 	 */
-	if (suser(td))
+	if (suser(td) != 0)
 		fsflags |= MNT_NOSUID | MNT_NODEV | MNT_USER;
 	/*
 	 * Get vnode to be covered
 	 */
 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, fspath, td);
-	if ((error = namei(&nd)) != 0)
+	error = namei(&nd);
+	if (error != 0)
 		return (error);
 	NDFREE(&nd, NDF_ONLY_PNBUF);
 	vp = nd.ni_vp;
@@ -728,18 +741,13 @@ vfs_domount(
 			return (EOPNOTSUPP);	/* Needs translation */
 		}
 		/*
-		 * Only root, or the user that did the original mount is
-		 * permitted to update it.
+		 * Only privileged root, or (if MNT_USER is set) the user that
+		 * did the original mount is permitted to update it.
 		 */
-		if ((mp->mnt_flag & MNT_USER) != 0) {
-			if (mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
-				if ((error = suser(td)) != 0) {
-					vput(vp);
-					return (error);
-				}
-			}
-		} else {
-			if ((error = suser(td)) != 0) {
+		if ((mp->mnt_flag & MNT_USER) == 0 ||
+		    mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
+			error = suser(td);
+			if (error != 0) {
 				vput(vp);
 				return (error);
 			}
@@ -772,18 +780,19 @@ vfs_domount(
 	 * onto which we are attempting to mount.
 	 */
 	error = VOP_GETATTR(vp, &va, td->td_ucred, td);
-	if (error) {
+	if (error != 0) {
 		vput(vp);
 		return (error);
 	}
 	if (va.va_uid != td->td_ucred->cr_uid) {
 		error = suser(td);
-		if (error) {
+		if (error != 0) {
 			vput(vp);
 			return (error);
 		}
 	}
-	if ((error = vinvalbuf(vp, V_SAVE, td->td_ucred, td, 0, 0)) != 0) {
+	error = vinvalbuf(vp, V_SAVE, td->td_ucred, td, 0, 0);
+	if (error != 0) {
 		vput(vp);
 		return (error);
 	}
@@ -792,17 +801,17 @@ vfs_domount(
 		return (ENOTDIR);
 	}
 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
-		if (!strcmp(vfsp->vfc_name, fstype))
+		if (strcmp(vfsp->vfc_name, fstype) == 0)
 			break;
 	if (vfsp == NULL) {
 		/* Only load modules for root (very important!). */
 		error = suser(td);
-		if (error) {
+		if (error != 0) {
 			vput(vp);
 			return (error);
 		}
 		error = securelevel_gt(td->td_ucred, 0);
-		if (error) {
+		if (error != 0) {
 			vput(vp);
 			return (error);
 		}
@@ -816,7 +825,7 @@ vfs_domount(
 		lf->userrefs++;
 		/* Look up again to see if the VFS was loaded. */
 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
-			if (!strcmp(vfsp->vfc_name, fstype))
+			if (strcmp(vfsp->vfc_name, fstype) == 0)
 				break;
 		if (vfsp == NULL) {
 			lf->userrefs--;
@@ -839,7 +848,7 @@ vfs_domount(
 	 * Allocate and initialize the filesystem.
 	 */
 	error = vfs_mount_alloc(vp, vfsp, fspath, td, &mp);
-	if (error) {
+	if (error != 0) {
 		vput(vp);
 		return (error);
 	}
@@ -855,7 +864,7 @@ update:
 	 */
 	if ((compat == 0) == (mp->mnt_op->vfs_mount != NULL)) {
 		printf("%s doesn't support the %s mount syscall\n",
-		    mp->mnt_vfc->vfc_name, compat? "old" : "new");
+		    mp->mnt_vfc->vfc_name, compat ? "old" : "new");
 		VI_LOCK(vp);
 		vp->v_iflag &= ~VI_MOUNT;
 		VI_UNLOCK(vp);
@@ -881,9 +890,9 @@ update:
 	 * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
 	 * get.  No freeing of cn_pnbuf.
 	 */
-	error = compat? VFS_MOUNT(mp, fspath, fsdata, &nd, td) :
+	error = compat ? VFS_MOUNT(mp, fspath, fsdata, &nd, td) :
 	    VFS_NMOUNT(mp, &nd, td);
-	if (!error) {
+	if (error == 0) {
 		if (mp->mnt_opt != NULL)
 			vfs_freeopts(mp->mnt_opt);
 		mp->mnt_opt = mp->mnt_optnew;
@@ -896,10 +905,10 @@ update:
 	if (mp->mnt_flag & MNT_UPDATE) {
 		if (mp->mnt_kern_flag & MNTK_WANTRDWR)
 			mp->mnt_flag &= ~MNT_RDONLY;
-		mp->mnt_flag &=~
-		    (MNT_UPDATE | MNT_RELOAD | MNT_FORCE | MNT_SNAPSHOT);
-		mp->mnt_kern_flag &=~ MNTK_WANTRDWR;
-		if (error) {
+		mp->mnt_flag &=
+		    ~(MNT_UPDATE | MNT_RELOAD | MNT_FORCE | MNT_SNAPSHOT);
+		mp->mnt_kern_flag &= ~MNTK_WANTRDWR;
+		if (error != 0) {
 			mp->mnt_flag = flag;
 			mp->mnt_kern_flag = kern_flag;
 		}
@@ -923,7 +932,7 @@ update:
 	 * Put the new filesystem on the mount list after root.
 	 */
 	cache_purge(vp);
-	if (!error) {
+	if (error == 0) {
 		struct vnode *newdp;
 
 		VI_LOCK(vp);
@@ -941,7 +950,8 @@ update:
 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
 			error = vfs_allocate_syncvnode(mp);
 		vfs_unbusy(mp, td);
-		if ((error = VFS_START(mp, 0, td)) != 0)
+		error = VFS_START(mp, 0, td);
+		if (error != 0)
 			vrele(vp);
 	} else {
 		VI_LOCK(vp);
@@ -1026,18 +1036,16 @@ unmount(td, uap)
 	char *pathbuf;
 	int error, id0, id1;
 
-	/* unmount(2) is not permitted inside the jail. */
 	if (jailed(td->td_ucred))
 		return (EPERM);
-
 	if (usermount == 0) {
-		if ((error = suser(td)) != 0)
+		error = suser(td);
+		if (error != 0)
 			return (error);
 	}
-
 	pathbuf = malloc(MNAMELEN, M_TEMP, M_WAITOK);
 	error = copyinstr(uap->path, pathbuf, MNAMELEN, NULL);
-	if (error) {
+	if (error != 0) {
 		free(pathbuf, M_TEMP);
 		return (error);
 	}
@@ -1049,16 +1057,18 @@ unmount(td, uap)
 		}
 
 		mtx_lock(&mountlist_mtx);
-		TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list)
+		TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
 			if (mp->mnt_stat.f_fsid.val[0] == id0 &&
 			    mp->mnt_stat.f_fsid.val[1] == id1)
 				break;
+		}
 		mtx_unlock(&mountlist_mtx);
 	} else {
 		mtx_lock(&mountlist_mtx);
-		TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list)
+		TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
 			if (strcmp(mp->mnt_stat.f_mntonname, pathbuf) == 0)
 				break;
+		}
 		mtx_unlock(&mountlist_mtx);
 	}
 	free(pathbuf, M_TEMP);
@@ -1073,16 +1083,13 @@ unmount(td, uap)
 	}
 
 	/*
-	 * Only root, or the user that did the original mount is
-	 * permitted to unmount this filesystem.
+	 * Only privileged root, or (if MNT_USER is set) the user that did the
+	 * original mount is permitted to unmount this filesystem.
 	 */
-	if ((mp->mnt_flag & MNT_USER) != 0) {
-		if (mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
-			if ((error = suser(td)) != 0)
-				return (error);
-		}
-	} else {
-		if ((error = suser(td)) != 0)
+	if ((mp->mnt_flag & MNT_USER) == 0 ||
+	    mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
+		error = suser(td);
+		if (error != 0)
 			return (error);
 	}
 
@@ -1118,7 +1125,7 @@ dounmount(mp, flags, td)
 		mp->mnt_kern_flag |= MNTK_UNMOUNTF;
 	error = lockmgr(&mp->mnt_lock, LK_DRAIN | LK_INTERLOCK |
 	    ((flags & MNT_FORCE) ? 0 : LK_NOWAIT), &mountlist_mtx, td);
-	if (error) {
+	if (error != 0) {
 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
 		if (mp->mnt_kern_flag & MNTK_MWAIT)
 			wakeup(mp);
@@ -1131,7 +1138,7 @@ dounmount(mp, flags, td)
 
 	vfs_msync(mp, MNT_WAIT);
 	async_flag = mp->mnt_flag & MNT_ASYNC;
-	mp->mnt_flag &=~ MNT_ASYNC;
+	mp->mnt_flag &= ~MNT_ASYNC;
 	cache_purgevfs(mp);	/* remove cache entries for this file sys */
 	if (mp->mnt_syncer != NULL)
 		vrele(mp->mnt_syncer);
@@ -1155,7 +1162,7 @@ dounmount(mp, flags, td)
 		error = VFS_UNMOUNT(mp, flags, td);
 	}
 	vn_finished_write(mp);
-	if (error) {
+	if (error != 0) {
 		/* Undo cdir/rdir and rootvnode changes made above. */
 		if ((flags & MNT_FORCE) && VFS_ROOT(mp, &fsrootvp) == 0) {
 			if (mp->mnt_vnodecovered != NULL)
@@ -1167,7 +1174,7 @@ dounmount(mp, flags, td)
 			vput(fsrootvp);
 		}
 		if ((mp->mnt_flag & MNT_RDONLY) == 0 && mp->mnt_syncer == NULL)
-			(void) vfs_allocate_syncvnode(mp);
+			vfs_allocate_syncvnode(mp);
 		mtx_lock(&mountlist_mtx);
 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
 		mp->mnt_flag |= async_flag;
@@ -1179,7 +1186,8 @@ dounmount(mp, flags, td)
 	}
 	mtx_lock(&mountlist_mtx);
 	TAILQ_REMOVE(&mountlist, mp, mnt_list);
-	if ((coveredvp = mp->mnt_vnodecovered) != NULL)
+	coveredvp = mp->mnt_vnodecovered;
+	if (coveredvp != NULL)
 		coveredvp->v_mountedhere = NULL;
 	mtx_unlock(&mountlist_mtx);
 	vfs_mount_destroy(mp, td);
@@ -1207,13 +1215,14 @@ vfs_rootmountalloc(fstypename, devname, 
 
 	if (fstypename == NULL)
 		return (ENODEV);
-	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
-		if (!strcmp(vfsp->vfc_name, fstypename))
+	for (vfsp = vfsconf; vfsp != NULL; vfsp = vfsp->vfc_next) {
+		if (strcmp(vfsp->vfc_name, fstypename) == 0)
 			break;
+	}
 	if (vfsp == NULL)
 		return (ENODEV);
 	error = vfs_mount_alloc(NULLVP, vfsp, "/", td, &mp);
-	if (error)
+	if (error != 0)
 		return (error);
 	mp->mnt_flag |= MNT_RDONLY | MNT_ROOTFS;
 	strlcpy(mp->mnt_stat.f_mntfromname, devname, MNAMELEN);
@@ -1266,10 +1275,11 @@ vfs_mountroot(void)
 	 * supplied via some other means.  This is the preferred
 	 * mechanism.
 	 */
-	if ((cp = getenv("vfs.root.mountfrom")) != NULL) {
+	cp = getenv("vfs.root.mountfrom");
+	if (cp != NULL) {
 		error = vfs_mountroot_try(cp);
 		freeenv(cp);
-		if (!error)
+		if (error == 0)
 			return;
 	}
 
@@ -1287,9 +1297,10 @@ vfs_mountroot(void)
 	 * it now.
 	 */
 #ifdef ROOTDEVNAME
-	if (!(boothowto & RB_DFLTROOT))
+	if (!(boothowto & RB_DFLTROOT)) {
 		if (!vfs_mountroot_try(ROOTDEVNAME))
 			return;
+	}
 #endif
 
 	/*
@@ -1335,8 +1346,8 @@ vfs_mountroot_try(char *mountfrom)
 		goto done;
 
 	/* allocate a root mount */
-	error = vfs_rootmountalloc(vfsname, path[0] != 0 ? path : ROOTNAME,
-				   &mp);
+	error = vfs_rootmountalloc(vfsname,
+	    path[0] != '\0' ? path : ROOTNAME, &mp);
 	if (error != 0) {
 		printf("Can't allocate root mount for filesystem '%s': %d\n",
 		       vfsname, error);
@@ -1344,7 +1355,7 @@ vfs_mountroot_try(char *mountfrom)
 	}
 
 	/* do our best to set rootdev */
-	if ((path[0] != 0) && setrootbyname(path))
+	if (path[0] != '\0' && setrootbyname(path))
 		printf("setrootbyname failed\n");
 
 	/* If the root device is a type "memory disk", mount RW */
@@ -1377,7 +1388,7 @@ done:
 		vfs_unbusy(mp, curthread);
 		error = VFS_START(mp, 0, curthread);
 	}
-	return(error);
+	return (error);
 }
 
 /*
@@ -1400,7 +1411,7 @@ vfs_mountroot_ask(void)
 		printf("  <empty line>       Abort manual input\n");
 		printf("\nmountroot> ");
 		gets(name);
-		if (name[0] == 0)
+		if (name[0] == '\0')
 			return(1);
 		if (name[0] == '?') {
 			printf("\nList of GEOM managed disk devices:\n  ");