Fixed loading of vfs's. The Lite2 merge added unnecessary compatibility

cruft and resulted in loading usually following a null pointer.  Use
something closer to the pre-Lite2 code, including not making a copy of
the new filesystem's config info.  Not making a copy also fixes a race
for loading and a memory leak for unloading.

Fixed unloading of vfs's.  maxvfsconf wasn't maintained.

Look up the vfs to unload by name instead of by number.  The numbers
should go away as soon as all mount utilities are converted.

1 files changed, 20 insertions, 41 deletions

diff --git a/sys/kern/kern_lkm.c b/sys/kern/kern_lkm.c
index 2a5fc52..19e0290 100644
--- a/sys/kern/kern_lkm.c
+++ b/sys/kern/kern_lkm.c
@@ -30,7 +30,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id$
+ * $Id: kern_lkm.c,v 1.36 1997/02/22 09:39:06 peter Exp $
  */
 
 #include <sys/param.h>
@@ -604,11 +604,9 @@ _lkm_vfs(lkmtp, cmd)
 {
 	struct lkm_vfs *args = lkmtp->private.lkm_vfs;
 	struct vfsconf *vfc = args->lkm_vfsconf;
-	struct vfsconf *vfsp, *lastvfsp, *prev_vfsp, *new_vfc;
-	int i;
+	struct vfsconf *vfsp, *prev_vfsp;
+	int i, maxtypenum;
 	int err = 0;
-	char fstypename[MFSNAMELEN];
-	int neednamesearch = 1;
 
 	switch(cmd) {
 	case LKM_E_LOAD:
@@ -616,26 +614,9 @@ _lkm_vfs(lkmtp, cmd)
 		if (lkmexists(lkmtp))
 			return(EEXIST);
 
-		/* check to see if filesystem already exists */
-		vfsp = NULL;
-#ifdef COMPAT_43	/* see vfs_syscalls.c:mount() */
-		if (vfc->vfc_typenum < maxvfsconf) {
-			neednamesearch = 0;
-			for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
-				if (vfsp->vfc_typenum == vfc->vfc_typenum)
-					break;
-			if (vfsp != NULL) {
-				neednamesearch = 1;
-				strncpy(fstypename, vfsp->vfc_name, MFSNAMELEN);
-			}
-		} else
-#endif /* COMPAT_43 */
-		if (neednamesearch) {
-			strncpy(fstypename, vfc->vfc_name, MFSNAMELEN);
-			for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
-				if (!strcmp(vfsp->vfc_name, fstypename)) {
-					return EEXIST;
-				}
+		for (vfsp = vfsconf; vfsp->vfc_next; vfsp = vfsp->vfc_next) {
+			if (!strcmp(vfc->vfc_name, vfsp->vfc_name)) {
+				return EEXIST;
 			}
 		}
 
@@ -645,21 +626,10 @@ _lkm_vfs(lkmtp, cmd)
 		}
 		args->lkm_offset = vfc->vfc_typenum = i;
 
-		if (maxvfsconf <= vfsp->vfc_typenum)
-			maxvfsconf = vfsp->vfc_typenum + 1;
-
-		/* find vfsconf tail */
-		for (lastvfsp = vfsconf; lastvfsp->vfc_next;
-					lastvfsp = lastvfsp->vfc_next) ;
+		if (maxvfsconf <= i)
+			maxvfsconf = i + 1;
 
-		/* make copy */
-/* possible race condition if vfsconf changes while we wait XXX JH */
-		MALLOC(new_vfc, struct vfsconf *, sizeof(struct vfsconf),
-				M_VFSCONF, M_WAITOK);
-		*new_vfc = *vfc;
-		vfc = new_vfc;
-
-		lastvfsp->vfc_next = vfc;
+		vfsp->vfc_next = vfc;
 		vfc->vfc_next = NULL;
 
 		/* like in vfs_op_init */
@@ -673,7 +643,7 @@ _lkm_vfs(lkmtp, cmd)
 		/*
 		 * Call init function for this VFS...
 		 */
-	 	(*(vfsp->vfc_vfsops->vfs_init))(vfsp);
+	 	(*(vfc->vfc_vfsops->vfs_init))(vfc);
 
 		/* done! */
 		break;
@@ -685,7 +655,7 @@ _lkm_vfs(lkmtp, cmd)
 		prev_vfsp = NULL;
 		for (vfsp = vfsconf; vfsp;
 				prev_vfsp = vfsp, vfsp = vfsp->vfc_next) {
-			if (vfsp->vfc_typenum == vfc->vfc_typenum)
+			if (!strcmp(vfc->vfc_name, vfsp->vfc_name))
 				break;
 		}
 		if (vfsp == NULL) {
@@ -700,6 +670,15 @@ _lkm_vfs(lkmtp, cmd)
 
 		prev_vfsp->vfc_next = vfsp->vfc_next;
 
+		/*
+		 * Maintain maxvfsconf.
+		 */
+		maxtypenum = 0;
+		for (vfsp = vfsconf; vfsp != NULL; vfsp = vfsp->vfc_next)
+			if (maxtypenum < vfsp->vfc_typenum)
+				maxtypenum = vfsp->vfc_typenum;
+		maxvfsconf = maxtypenum + 1;
+
 		break;
 
 	case LKM_E_STAT:	/* no special handling... */