- Introduce a new struct xvfsconf, the userland version of struct vfsconf.

- Make getvfsbyname() take a struct xvfsconf *.
- Convert several consumers of getvfsbyname() to use struct xvfsconf.
- Correct the getvfsbyname.3 manpage.
- Create a new vfs.conflist sysctl to dump all the struct xvfsconf in the
  kernel, and rewrite getvfsbyname() to use this instead of the weird
  existing API.
- Convert some {set,get,end}vfsent() consumers to use the new vfs.conflist
  sysctl.
- Convert a vfsload() call in nfsiod.c to kldload() and remove the useless
  vfsisloadable() and endvfsent() calls.
- Add a warning printf() in vfs_sysctl() to tell people they are using
  an old userland.

After these changes, it's possible to modify struct vfsconf without
breaking the binary compatibility.  Please note that these changes don't
break this compatibility either.

When bp will have updated mount_smbfs(8) with the patch I sent him, there
will be no more consumers of the {set,get,end}vfsent(), vfsisloadable()
and vfsload() API, and I will promptly delete it.

bin/df/df.c

@@ -491,31 +491,40 @@ static char *
 makenetvfslist(void)
 {
 	char *str, *strptr, **listptr;
-	int mib[3], maxvfsconf, cnt=0, i;
-	size_t miblen;
-	struct ovfsconf *ptr;
+	struct xvfsconf *xvfsp;
+	size_t buflen;
+	int cnt, i, maxvfsconf;
 
-	mib[0] = CTL_VFS; mib[1] = VFS_GENERIC; mib[2] = VFS_MAXTYPENUM;
-	miblen=sizeof(maxvfsconf);
-	if (sysctl(mib, (unsigned int)(sizeof(mib) / sizeof(mib[0])),
-	    &maxvfsconf, &miblen, NULL, 0)) {
-		warnx("sysctl failed");
+	if (sysctlbyname("vfs.conflist", NULL, &buflen, NULL, 0) < 0) {
+		warn("sysctl(vfs.conflist)");
 		return (NULL);
 	}
+	xvfsp = malloc(buflen);
+	if (xvfsp == NULL) {
+		warnx("malloc failed");
+		return (NULL);
+	}
+	if (sysctlbyname("vfs.conflist", xvfsp, &buflen, NULL, 0) < 0) {
+		warn("sysctl(vfs.conflist)");
+		return (NULL);
+	}
+	maxvfsconf = buflen / sizeof(struct xvfsconf);
 
 	if ((listptr = malloc(sizeof(char*) * maxvfsconf)) == NULL) {
 		warnx("malloc failed");
 		return (NULL);
 	}
 
-	for (ptr = getvfsent(); ptr; ptr = getvfsent())
-		if (ptr->vfc_flags & VFCF_NETWORK) {
-			listptr[cnt++] = strdup(ptr->vfc_name);
+	for (cnt = 0, i = 0; i < maxvfsconf; i++) {
+		if (xvfsp->vfc_flags & VFCF_NETWORK) {
+			listptr[cnt++] = strdup(xvfsp->vfc_name);
 			if (listptr[cnt-1] == NULL) {
 				warnx("malloc failed");
 				return (NULL);
 			}
 		}
+		xvfsp++;
+	}
 
 	if (cnt == 0 ||
 	    (str = malloc(sizeof(char) * (32 * cnt + cnt + 2))) == NULL) {

lib/libc/gen/getvfsbyname.3

@@ -44,7 +44,7 @@
 .In sys/param.h
 .In sys/mount.h
 .Ft int
-.Fn getvfsbyname "const char *name" "struct vfsconf *vfc"
+.Fn getvfsbyname "const char *name" "struct xvfsconf *vfc"
 .Sh DESCRIPTION
 The
 .Fn getvfsbyname
@@ -52,11 +52,11 @@ function provides access to information about a
 filesystem module that is configured in the kernel.
 If successful,
 the requested filesystem
-.Fa vfsconf
+.Fa xvfsconf
 is returned in the location pointed to by
 .Fa vfc .
 The fields in a
-.Dq Li struct vfsconf
+.Dq Li struct xvfsconf
 are defined as follows:
 .Pp
 .Bl -tag -compact -width vfc_refcount
@@ -67,8 +67,24 @@ the filesystem type number assigned by the kernel
 .It vfc_refcount
 the number of active mount points using the filesystem
 .It vfc_flags
-flag bits as described in
-.Xr getvfsent 3
+flag bits, as described below
+.El
+.Pp
+The flags are defined as follows:
+.Pp
+.Bl -tag -width VFCF_SYNTHETIC -compact
+.It Dv VFCF_STATIC
+statically compiled into kernel
+.It Dv VFCF_NETWORK
+may get data over the network
+.It Dv VFCF_READONLY
+writes are not implemented
+.It Dv VFCF_SYNTHETIC
+data does not represent real files
+.It Dv VFCF_LOOPBACK
+aliases some other mounted FS
+.It Dv VFCF_UNICODE
+stores file names as Unicode
 .El
 .Sh RETURN VALUES
 .Rv -std getvfsbyname
@@ -86,7 +102,6 @@ specifies a filesystem that is unknown or not configured in the kernel.
 .El
 .Sh SEE ALSO
 .Xr mount 2 ,
-.Xr getvfsent 3 ,
 .Xr sysctl 3 ,
 .Xr mount 8 ,
 .Xr sysctl 8

lib/libc/gen/getvfsbyname.c

@@ -41,39 +41,43 @@ __FBSDID("$FreeBSD$");
 #include <sys/mount.h>
 #include <sys/sysctl.h>
 #include <errno.h>
+#include <stdlib.h>
+#include <string.h>
 
 /*
  * Given a filesystem name, determine if it is resident in the kernel,
- * and if it is resident, return its vfsconf structure.
+ * and if it is resident, return its xvfsconf structure.
  */
+int
 getvfsbyname(fsname, vfcp)
 	const char *fsname;
-	struct vfsconf *vfcp;
+	struct xvfsconf *vfcp;
 {
 #ifdef	__NETBSD_SYSCALLS
 	errno = ENOSYS;
 #else
-	int name[4], maxtypenum, cnt;
+	struct xvfsconf *xvfsp;
 	size_t buflen;
+	int cnt, i;
 
-	name[0] = CTL_VFS;
-	name[1] = VFS_GENERIC;
-	name[2] = VFS_MAXTYPENUM;
-	buflen = 4;
-	if (sysctl(name, 3, &maxtypenum, &buflen, (void *)0, (size_t)0) < 0)
+	if (sysctlbyname("vfs.conflist", NULL, &buflen, NULL, 0) < 0)
+		return (-1);
+	xvfsp = malloc(buflen);
+	if (xvfsp == NULL)
+		return (-1);
+	if (sysctlbyname("vfs.conflist", xvfsp, &buflen, NULL, 0) < 0) {
+		free(xvfsp);
 		return (-1);
-	name[2] = VFS_CONF;
-	buflen = sizeof *vfcp;
-	for (cnt = 0; cnt < maxtypenum; cnt++) {
-		name[3] = cnt;
-		if (sysctl(name, 4, vfcp, &buflen, (void *)0, (size_t)0) < 0) {
-			if (errno != EOPNOTSUPP)
-				return (-1);
-			continue;
-		}
-		if (!strcmp(fsname, vfcp->vfc_name))
-			return (0);
 	}
+	cnt = buflen / sizeof(struct xvfsconf);
+	for (i = 0; i < cnt; i++) {
+		if (strcmp(fsname, xvfsp[i].vfc_name) == 0) {
+			memcpy(vfcp, xvfsp + i, sizeof(struct xvfsconf));
+			free(xvfsp);
+			return (0);
+		}
+	}
+	free(xvfsp);
 	errno = ENOENT;
 #endif
 	return (-1);

lib/libc/gen/getvfsent.c

@@ -21,7 +21,6 @@ __FBSDID("$FreeBSD$");
 #include <paths.h>
 
 /* XXX hide some compatibility problems. */
-#undef getvfsbyname
 #define vfsconf		ovfsconf
 
 static struct vfsconf *_vfslist = 0;
@@ -80,36 +79,6 @@ getvfsent(void)
 	return &_vfsconf;
 }
 
-struct vfsconf *
-getvfsbyname(const char *name)
-{
-	int i;
-
-	if(!_vfslist && !initvfs()) {
-		return 0;
-	}
-
-	for(i = 0; i < _vfslistlen; i++) {
-		if( ! strcmp(_vfslist[i].vfc_name, name) )
-			break;
-	}
-
-	if(i < _vfslistlen) {
-		_vfsconf = _vfslist[i];
-	}
-
-	if(!_vfs_keeplist) {
-		free(_vfslist);
-		_vfslist = 0;
-	}
-
-	if(i < _vfslistlen) {
-		return &_vfsconf;
-	} else {
-		return 0;
-	}
-}
-
 struct vfsconf *
 getvfsbytype(int type)
 {

sbin/nfsiod/Makefile

@@ -2,6 +2,7 @@
 # $FreeBSD$
 
 PROG=	nfsiod
+WARNS?=	6
 MAN=	nfsiod.8
 
 .include <bsd.prog.mk>

sbin/nfsiod/nfsiod.8

@@ -69,9 +69,7 @@ detects that the running kernel does not include
 support, it will attempt to load a loadable kernel module containing
 .Tn NFS
 code, using
-.Xr kldload 8
-by way of
-.Xr vfsload 3 .
+.Xr kldload 2 .
 If this fails, or no
 .Tn NFS
 KLD was available,
@@ -81,8 +79,8 @@ exits with an error.
 .Ex -std
 .Sh SEE ALSO
 .Xr nfsstat 1 ,
+.Xr kldload 2 ,
 .Xr nfssvc 2 ,
-.Xr kldload 8 ,
 .Xr mountd 8 ,
 .Xr nfsd 8 ,
 .Xr rpcbind 8

sbin/nfsiod/nfsiod.c

@@ -51,6 +51,7 @@ static const char rcsid[] =
 #include <sys/param.h>
 #include <sys/syslog.h>
 #include <sys/wait.h>
+#include <sys/linker.h>
 #include <sys/mount.h>
 #include <sys/time.h>
 #include <sys/sysctl.h>
@@ -73,16 +74,15 @@ int
 main(int argc, char *argv[])
 {
 	int ch;
-	struct vfsconf vfc;
+	struct xvfsconf vfc;
 	int error;
 	unsigned int iodmin, iodmax, num_servers;
 	size_t len;
 
 	error = getvfsbyname("nfs", &vfc);
-	if (error && vfsisloadable("nfs")) {
-		if (vfsload("nfs"))
-			err(1, "vfsload(nfs)");
-		endvfsent();	/* flush cache */
+	if (error) {
+		if (kldload("nfs"))
+			err(1, "kldload(nfs)");
 		error = getvfsbyname("nfs", &vfc);
 	}
 	if (error)

sbin/umount/umount.c

@@ -200,7 +200,7 @@ main(int argc, char *argv[])
 int
 umountall(char **typelist)
 {
-	struct vfsconf vfc;
+	struct xvfsconf vfc;
 	struct fstab *fs;
 	int rval;
 	char *cp;

sys/kern/vfs_subr.c

@@ -2629,6 +2629,56 @@ DB_SHOW_COMMAND(lockedvnods, lockedvnodes)
 }
 #endif
 
+/*
+ * Fill in a struct xvfsconf based on a struct vfsconf.
+ */
+static void
+vfsconf2x(struct vfsconf *vfsp, struct xvfsconf *xvfsp)
+{
+
+	strcpy(xvfsp->vfc_name, vfsp->vfc_name);
+	xvfsp->vfc_typenum = vfsp->vfc_typenum;
+	xvfsp->vfc_refcount = vfsp->vfc_refcount;
+	xvfsp->vfc_flags = vfsp->vfc_flags;
+	/*
+	 * These are unused in userland, we keep them
+	 * to not break binary compatibility.
+	 */
+	xvfsp->vfc_vfsops = NULL;
+	xvfsp->vfc_next = NULL;
+}
+
+static int
+sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
+{
+	struct vfsconf *vfsp;
+	struct xvfsconf *xvfsp;
+	int cnt, error, i;
+
+	cnt = 0;
+	for (vfsp = vfsconf; vfsp != NULL; vfsp = vfsp->vfc_next)
+		cnt++;
+	xvfsp = malloc(sizeof(struct xvfsconf) * cnt, M_TEMP, M_WAITOK);
+	/*
+	 * Handle the race that we will have here when struct vfsconf
+	 * will be locked down by using both cnt and checking vfc_next
+	 * against NULL to determine the end of the loop.  The race will
+	 * happen because we will have to unlock before calling malloc().
+	 * We are protected by Giant for now.
+	 */
+	i = 0;
+	for (vfsp = vfsconf; vfsp != NULL && i < cnt; vfsp = vfsp->vfc_next) {
+		vfsconf2x(vfsp, xvfsp + i);
+		i++;
+	}
+	error = SYSCTL_OUT(req, xvfsp, sizeof(struct xvfsconf) * i);
+	free(xvfsp, M_TEMP);
+	return (error);
+}
+
+SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLFLAG_RD, NULL, 0, sysctl_vfs_conflist,
+    "S,xvfsconf", "List of all configured filesystems");
+
 /*
  * Top level filesystem related information gathering.
  */
@@ -2640,6 +2690,10 @@ vfs_sysctl(SYSCTL_HANDLER_ARGS)
 	int *name = (int *)arg1 - 1;	/* XXX */
 	u_int namelen = arg2 + 1;	/* XXX */
 	struct vfsconf *vfsp;
+	struct xvfsconf xvfsp;
+
+	printf("WARNING: userland calling deprecated sysctl, "
+	    "please rebuild world\n");
 
 #if 1 || defined(COMPAT_PRELITE2)
 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
@@ -2647,21 +2701,6 @@ vfs_sysctl(SYSCTL_HANDLER_ARGS)
 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
 #endif
 
-	/* XXX the below code does not compile; vfs_sysctl does not exist. */
-#ifdef notyet
-	/* all sysctl names at this level are at least name and field */
-	if (namelen < 2)
-		return (ENOTDIR);		/* overloaded */
-	if (name[0] != VFS_GENERIC) {
-		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
-			if (vfsp->vfc_typenum == name[0])
-				break;
-		if (vfsp == NULL)
-			return (EOPNOTSUPP);
-		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
-		    oldp, oldlenp, newp, newlen, td));
-	}
-#endif
 	switch (name[1]) {
 	case VFS_MAXTYPENUM:
 		if (namelen != 2)
@@ -2675,12 +2714,13 @@ vfs_sysctl(SYSCTL_HANDLER_ARGS)
 				break;
 		if (vfsp == NULL)
 			return (EOPNOTSUPP);
-		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
+		vfsconf2x(vfsp, &xvfsp);
+		return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
 	}
 	return (EOPNOTSUPP);
 }
 
-SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
+SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD | CTLFLAG_SKIP, vfs_sysctl,
 	"Generic filesystem");
 
 #if 1 || defined(COMPAT_PRELITE2)

sys/sys/mount.h

@@ -319,7 +319,30 @@ struct nfs_public {
  * type of filesystem supported by the kernel. These are searched at
  * mount time to identify the requested filesystem.
  */
+#ifdef _KERNEL
 struct vfsconf {
+	struct	vfsops *vfc_vfsops;	/* filesystem operations vector */
+	char	vfc_name[MFSNAMELEN];	/* filesystem type name */
+	int	vfc_typenum;		/* historic filesystem type number */
+	int	vfc_refcount;		/* number mounted of this type */
+	int	vfc_flags;		/* permanent flags */
+	struct	vfsoptdecl *vfc_opts;	/* mount options */
+	struct	vfsconf *vfc_next;	/* next in list */
+};
+#endif /* _KERNEL */
+
+/* Userland version of the struct vfsconf. */
+struct xvfsconf {
+	struct	vfsops *vfc_vfsops;	/* filesystem operations vector */
+	char	vfc_name[MFSNAMELEN];	/* filesystem type name */
+	int	vfc_typenum;		/* historic filesystem type number */
+	int	vfc_refcount;		/* number mounted of this type */
+	int	vfc_flags;		/* permanent flags */
+	struct	vfsconf *vfc_next;	/* next in list */
+};
+
+/* Userland version of the struct vfsconf. */
+struct xvfsconf {
 	struct	vfsops *vfc_vfsops;	/* filesystem operations vector */
 	char	vfc_name[MFSNAMELEN];	/* filesystem type name */
 	int	vfc_typenum;		/* historic filesystem type number */
@@ -516,11 +539,9 @@ int	unmount(const char *, int);
 
 /* C library stuff */
 void	endvfsent(void);
-struct	ovfsconf *getvfsbyname(const char *);
 struct	ovfsconf *getvfsbytype(int);
 struct	ovfsconf *getvfsent(void);
-#define	getvfsbyname	new_getvfsbyname
-int	new_getvfsbyname(const char *, struct vfsconf *);
+int	getvfsbyname(const char *, struct xvfsconf *);
 void	setvfsent(int);
 int	vfsisloadable(const char *);
 int	vfsload(const char *);

usr.bin/find/function.c

@@ -834,7 +834,7 @@ c_fstype(option, argvp)
 {
 	char *fsname;
 	PLAN *new;
-	struct vfsconf vfc;
+	struct xvfsconf vfc;
 
 	fsname = nextarg(option, argvp);
 	ftsoptions &= ~FTS_NOSTAT;

usr.bin/lsvfs/Makefile

@@ -1,5 +1,6 @@
 # $FreeBSD$
 
 PROG=	lsvfs
+WARNS?=	6
 
 .include <bsd.prog.mk>

usr.bin/lsvfs/lsvfs.c

@@ -8,13 +8,12 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#define _NEW_VFSCONF
-
 #include <sys/param.h>
 #include <sys/mount.h>
 
 #include <err.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 #define FMT "%-32.32s %5d %s\n"
@@ -26,13 +25,11 @@ static const char *fmt_flags(int);
 int
 main(int argc, char **argv)
 {
-  int rv = 0;
-  struct vfsconf vfc;
-  struct ovfsconf *ovfcp;
+  int cnt, rv = 0, i; 
+  struct xvfsconf vfc, *xvfsp;
+  size_t buflen;
   argc--, argv++;
 
-  setvfsent(1);
-
   printf(HDRFMT, "Filesystem", "Refs", "Flags");
   fputs(DASHES, stdout);
 
@@ -46,13 +43,22 @@ main(int argc, char **argv)
       }
     }
   } else {
-    while ((ovfcp = getvfsent()) != NULL) {
-      printf(FMT, ovfcp->vfc_name, ovfcp->vfc_refcount,
-             fmt_flags(ovfcp->vfc_flags));
+    if (sysctlbyname("vfs.conflist", NULL, &buflen, NULL, 0) < 0)
+      err(1, "sysctl(vfs.conflist)");
+    xvfsp = malloc(buflen);
+    if (xvfsp == NULL)
+      errx(1, "malloc failed");
+    if (sysctlbyname("vfs.conflist", xvfsp, &buflen, NULL, 0) < 0)
+      err(1, "sysctl(vfs.conflist)");
+    cnt = buflen / sizeof(struct xvfsconf);
+
+    for (i = 0; i < cnt; i++) {
+      printf(FMT, xvfsp[i].vfc_name, xvfsp[i].vfc_refcount,
+             fmt_flags(xvfsp[i].vfc_flags));
     }
+    free(xvfsp);
   }
 
-  endvfsent();
   return rv;
 }