]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/vfs/vfs_lookup.c
xnu-1699.22.73.tar.gz
[apple/xnu.git] / bsd / vfs / vfs_lookup.c
index 9d8aea2993fc0352bfcb48c90d87b7ecdc32d5b2..10b885d51829894bb5e63e3a2ff6f6713a29a76c 100644 (file)
@@ -1,23 +1,29 @@
 /*
- * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
  * 
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
 /*
  *
  *     @(#)vfs_lookup.c        8.10 (Berkeley) 5/27/95
  */
+/*
+ * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
+ * support for mandatory and extensible security protections.  This notice
+ * is included in support of clause 2.2 (b) of the Apple Public License,
+ * Version 2.0.
+ */
 
 #include <sys/param.h>
+#include <sys/systm.h>
 #include <sys/syslimits.h>
 #include <sys/time.h>
 #include <sys/namei.h>
 #include <sys/vm.h>
-#include <sys/vnode.h>
-#include <sys/mount.h>
+#include <sys/vnode_internal.h>
+#include <sys/mount_internal.h>
 #include <sys/errno.h>
 #include <sys/malloc.h>
 #include <sys/filedesc.h>
-#include <sys/proc.h>
+#include <sys/proc_internal.h>
 #include <sys/kdebug.h>
 #include <sys/unistd.h>                /* For _PC_NAME_MAX */
+#include <sys/uio_internal.h>
+#include <sys/kauth.h>
+
+#include <security/audit/audit.h>
+
+#if CONFIG_MACF
+#include <security/mac_framework.h>
+#endif
+
+#if NAMEDRSRCFORK
+#include <sys/xattr.h>
+#endif
+/*
+ * The minimum volfs-style pathname is 9.
+ * Example:  "/.vol/1/2"
+ */
+#define VOLFS_MIN_PATH_LEN  9
+
+
+static void kdebug_lookup(struct vnode *dp, struct componentname *cnp);
 
-#if KTRACE
-#include <sys/ktrace.h>
+#if CONFIG_VOLFS
+static int vfs_getrealpath(const char * path, char * realpath, size_t bufsize, vfs_context_t ctx);
 #endif
 
+boolean_t      lookup_continue_ok(struct nameidata *ndp);
+int            lookup_traverse_mountpoints(struct nameidata *ndp, struct componentname *cnp, vnode_t dp, int vbusyflags, vfs_context_t ctx);
+int            lookup_handle_symlink(struct nameidata *ndp, vnode_t *new_dp, vfs_context_t ctx);
+int            lookup_authorize_search(vnode_t dp, struct componentname *cnp, int dp_authorized_in_cache, vfs_context_t ctx);
+void           lookup_consider_update_cache(vnode_t dvp, vnode_t vp, struct componentname *cnp, int nc_generation);
+int            lookup_handle_rsrc_fork(vnode_t dp, struct nameidata *ndp, struct componentname *cnp, int wantparent, vfs_context_t ctx);
+int            lookup_handle_found_vnode(struct nameidata *ndp, struct componentname *cnp, int rdonly, 
+                       int vbusyflags, int *keep_going, int nc_generation,
+                       int wantparent, int atroot, vfs_context_t ctx);
+int            lookup_handle_emptyname(struct nameidata *ndp, struct componentname *cnp, int wantparent);
+
 /*
  * Convert a pathname into a pointer to a locked inode.
  *
  *             call lookup to search path.
  *             if symbolic link, massage name in buffer and continue
  *     }
+ *
+ * Returns:    0                       Success
+ *             ENOENT                  No such file or directory
+ *             ELOOP                   Too many levels of symbolic links
+ *             ENAMETOOLONG            Filename too long
+ *             copyinstr:EFAULT        Bad address
+ *             copyinstr:ENAMETOOLONG  Filename too long
+ *             lookup:EBADF            Bad file descriptor
+ *             lookup:EROFS
+ *             lookup:EACCES
+ *             lookup:EPERM
+ *             lookup:ERECYCLE  vnode was recycled from underneath us in lookup.
+ *                                              This means we should re-drive lookup from this point.
+ *             lookup: ???
+ *             VNOP_READLINK:???
  */
 int
-namei(ndp)
-       register struct nameidata *ndp;
+namei(struct nameidata *ndp)
 {
-       register struct filedesc *fdp;  /* pointer to file descriptor state */
-       register char *cp;              /* pointer into pathname argument */
-       register struct vnode *dp;      /* the directory we are searching */
-       struct iovec aiov;              /* uio for reading symbolic links */
-       struct uio auio;
-       int error, linklen;
+       struct filedesc *fdp;   /* pointer to file descriptor state */
+       struct vnode *dp;       /* the directory we are searching */
+       struct vnode *usedvp = ndp->ni_dvp;  /* store pointer to vp in case we must loop due to
+                                                                                       heavy vnode pressure */
+       u_long cnpflags = ndp->ni_cnd.cn_flags; /* store in case we have to restore after loop */
+       int error;
        struct componentname *cnp = &ndp->ni_cnd;
-       struct proc *p = cnp->cn_proc;
+       vfs_context_t ctx = cnp->cn_context;
+       proc_t p = vfs_context_proc(ctx);
+#if CONFIG_AUDIT
+/* XXX ut should be from context */
+       uthread_t ut = (struct uthread *)get_bsdthread_info(current_thread());
+#endif
+
+       fdp = p->p_fd;
 
-       ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_proc->p_ucred;
 #if DIAGNOSTIC
-       if (!cnp->cn_cred || !cnp->cn_proc)
+       if (!vfs_context_ucred(ctx) || !p)
                panic ("namei: bad cred/proc");
        if (cnp->cn_nameiop & (~OPMASK))
                panic ("namei: nameiop contaminated with flags");
        if (cnp->cn_flags & OPMASK)
                panic ("namei: flags contaminated with nameiops");
 #endif
-       fdp = cnp->cn_proc->p_fd;
+
+       /*
+        * A compound VNOP found something that needs further processing:
+        * either a trigger vnode, a covered directory, or a symlink.
+        */
+       if (ndp->ni_flag & NAMEI_CONTLOOKUP) {
+               int rdonly, vbusyflags, keep_going, wantparent;
+
+               rdonly = cnp->cn_flags & RDONLY;
+               vbusyflags = ((cnp->cn_flags & CN_NBMOUNTLOOK) != 0) ? LK_NOWAIT : 0;
+               keep_going = 0;
+               wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
+
+               ndp->ni_flag &= ~(NAMEI_CONTLOOKUP);
+
+               error = lookup_handle_found_vnode(ndp, &ndp->ni_cnd, rdonly, vbusyflags, 
+                               &keep_going, ndp->ni_ncgeneration, wantparent, 0, ctx);
+               if (error)
+                       goto out_drop;
+               if (keep_going) {
+                       if ((cnp->cn_flags & ISSYMLINK) == 0) {
+                               panic("We need to keep going on a continued lookup, but for vp type %d (tag %d)\n", ndp->ni_vp->v_type, ndp->ni_vp->v_tag);
+                       }
+                       goto continue_symlink;
+               }
+
+               return 0;
+
+       }
+
+vnode_recycled:
 
        /*
         * Get a buffer for the name to be translated, and copy the
         * name into the buffer.
         */
        if ((cnp->cn_flags & HASBUF) == 0) {
-               MALLOC_ZONE(cnp->cn_pnbuf, caddr_t,
-                               MAXPATHLEN, M_NAMEI, M_WAITOK);
-               cnp->cn_pnlen = MAXPATHLEN;
+               cnp->cn_pnbuf = ndp->ni_pathbuf;
+               cnp->cn_pnlen = PATHBUFLEN;
        }
-       if (ndp->ni_segflg == UIO_SYSSPACE)
-               error = copystr(ndp->ni_dirp, cnp->cn_pnbuf,
-                           MAXPATHLEN, &ndp->ni_pathlen);
-       else
+#if LP64_DEBUG
+       if ((UIO_SEG_IS_USER_SPACE(ndp->ni_segflg) == 0)
+               && (ndp->ni_segflg != UIO_SYSSPACE)
+               && (ndp->ni_segflg != UIO_SYSSPACE32)) {
+               panic("%s :%d - invalid ni_segflg\n", __FILE__, __LINE__); 
+       }
+#endif /* LP64_DEBUG */
+
+retry_copy:
+       if (UIO_SEG_IS_USER_SPACE(ndp->ni_segflg)) {
                error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf,
-                           MAXPATHLEN, &ndp->ni_pathlen);
+                           cnp->cn_pnlen, (size_t *)&ndp->ni_pathlen);
+       } else {
+               error = copystr(CAST_DOWN(void *, ndp->ni_dirp), cnp->cn_pnbuf,
+                           cnp->cn_pnlen, (size_t *)&ndp->ni_pathlen);
+       }
+       if (error == ENAMETOOLONG && !(cnp->cn_flags & HASBUF)) {
+               MALLOC_ZONE(cnp->cn_pnbuf, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
+               if (cnp->cn_pnbuf == NULL) {
+                       error = ENOMEM;
+                       goto error_out;
+               }
+
+               cnp->cn_flags |= HASBUF;
+               cnp->cn_pnlen = MAXPATHLEN;
+               
+               goto retry_copy;
+       }
+       if (error)
+               goto error_out;
+
+#if CONFIG_VOLFS
+       /*
+        * Check for legacy volfs style pathnames.
+        *
+        * For compatibility reasons we currently allow these paths,
+        * but future versions of the OS may not support them.
+        */
+       if (ndp->ni_pathlen >= VOLFS_MIN_PATH_LEN &&
+           cnp->cn_pnbuf[0] == '/' &&
+           cnp->cn_pnbuf[1] == '.' &&
+           cnp->cn_pnbuf[2] == 'v' &&
+           cnp->cn_pnbuf[3] == 'o' &&
+           cnp->cn_pnbuf[4] == 'l' &&
+           cnp->cn_pnbuf[5] == '/' ) {
+               char * realpath;
+               int realpath_err;
+               /* Attempt to resolve a legacy volfs style pathname. */
+               MALLOC_ZONE(realpath, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
+               if (realpath) {
+                       /* 
+                        * We only error out on the ENAMETOOLONG cases where we know that
+                        * vfs_getrealpath translation succeeded but the path could not fit into
+                        * MAXPATHLEN characters.  In other failure cases, we may be dealing with a path
+                        * that legitimately looks like /.vol/1234/567 and is not meant to be translated
+                        */
+                       if ((realpath_err= vfs_getrealpath(&cnp->cn_pnbuf[6], realpath, MAXPATHLEN, ctx))) {
+                               FREE_ZONE(realpath, MAXPATHLEN, M_NAMEI);
+                               if (realpath_err == ENOSPC || realpath_err == ENAMETOOLONG){
+                                       error = ENAMETOOLONG;
+                                       goto error_out;
+                               }
+                       } else {
+                               if (cnp->cn_flags & HASBUF) {
+                                       FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
+                               }
+                               cnp->cn_pnbuf = realpath;
+                               cnp->cn_pnlen = MAXPATHLEN;
+                               ndp->ni_pathlen = strlen(realpath) + 1;
+                               cnp->cn_flags |= HASBUF | CN_VOLFSPATH;
+                       }
+               }
+       }
+#endif /* CONFIG_VOLFS */
+
+#if CONFIG_AUDIT
+       /* If we are auditing the kernel pathname, save the user pathname */
+       if (cnp->cn_flags & AUDITVNPATH1)
+               AUDIT_ARG(upath, ut->uu_cdir, cnp->cn_pnbuf, ARG_UPATH1); 
+       if (cnp->cn_flags & AUDITVNPATH2)
+               AUDIT_ARG(upath, ut->uu_cdir, cnp->cn_pnbuf, ARG_UPATH2); 
+#endif /* CONFIG_AUDIT */
+
        /*
         * Do not allow empty pathnames
         */
-       if (!error && *cnp->cn_pnbuf == '\0')
+       if (*cnp->cn_pnbuf == '\0') {
                error = ENOENT;
-
-       if (error) {
-               _FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
-               ndp->ni_vp = NULL;
-               return (error);
+               goto error_out;
        }
        ndp->ni_loopcnt = 0;
-#if KTRACE
-       if (KTRPOINT(cnp->cn_proc, KTR_NAMEI))
-               ktrnamei(cnp->cn_proc->p_tracep, cnp->cn_pnbuf);
-#endif
 
        /*
-        * Get starting point for the translation.
+        * determine the starting point for the translation.
         */
-       if ((ndp->ni_rootdir = fdp->fd_rdir) == NULL)
-               ndp->ni_rootdir = rootvnode;
-       dp = fdp->fd_cdir;
-       VREF(dp);
-       for (;;) {
-               /*
-                * Check if root directory should replace current directory.
-                * Done at start of translation and after symbolic link.
-                */
-               cnp->cn_nameptr = cnp->cn_pnbuf;
-               if (*(cnp->cn_nameptr) == '/') {
-                       vrele(dp);
-                       while (*(cnp->cn_nameptr) == '/') {
-                               cnp->cn_nameptr++;
-                               ndp->ni_pathlen--;
-                       }
-                       dp = ndp->ni_rootdir;
-                       VREF(dp);
+       if ((ndp->ni_rootdir = fdp->fd_rdir) == NULLVP) {
+               if ( !(fdp->fd_flags & FD_CHROOT))
+                       ndp->ni_rootdir = rootvnode;
+       }
+       cnp->cn_nameptr = cnp->cn_pnbuf;
+
+       ndp->ni_usedvp = NULLVP;
+
+       if (*(cnp->cn_nameptr) == '/') {
+               while (*(cnp->cn_nameptr) == '/') {
+                       cnp->cn_nameptr++;
+                       ndp->ni_pathlen--;
                }
+               dp = ndp->ni_rootdir;
+       } else if (cnp->cn_flags & USEDVP) {
+               dp = ndp->ni_dvp;
+               ndp->ni_usedvp = dp;
+       } else
+               dp = vfs_context_cwd(ctx);
+
+       if (dp == NULLVP || (dp->v_lflag & VL_DEAD)) {
+               error = ENOENT;
+               goto error_out;
+       }
+       ndp->ni_dvp = NULLVP;
+       ndp->ni_vp  = NULLVP;
+
+       for (;;) {
                ndp->ni_startdir = dp;
-               if (error = lookup(ndp)) {
-                       FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
-                       return (error);
+
+               if ( (error = lookup(ndp)) ) {
+                       goto error_out;
                }
                /*
                 * Check for symbolic link
                 */
                if ((cnp->cn_flags & ISSYMLINK) == 0) {
-                       if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) {
-                               FREE_ZONE(cnp->cn_pnbuf,
-                                               cnp->cn_pnlen, M_NAMEI);
-                       } else {
-                               cnp->cn_flags |= HASBUF;
-                       }
                        return (0);
                }
-               if ((cnp->cn_flags & LOCKPARENT) && ndp->ni_pathlen == 1)
-                       VOP_UNLOCK(ndp->ni_dvp, 0, p);
-               if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
-                       error = ELOOP;
+
+continue_symlink:
+               /* Gives us a new path to process, and a starting dir */
+               error = lookup_handle_symlink(ndp, &dp, ctx);
+               if (error != 0) {
                        break;
                }
-               if (ndp->ni_pathlen > 1) {
-                       MALLOC_ZONE(cp, char *, MAXPATHLEN, M_NAMEI, M_WAITOK);
-               } else {
-                       cp = cnp->cn_pnbuf;
-               }
-               aiov.iov_base = cp;
-               aiov.iov_len = MAXPATHLEN;
-               auio.uio_iov = &aiov;
-               auio.uio_iovcnt = 1;
-               auio.uio_offset = 0;
-               auio.uio_rw = UIO_READ;
-               auio.uio_segflg = UIO_SYSSPACE;
-               auio.uio_procp = (struct proc *)0;
-               auio.uio_resid = MAXPATHLEN;
-               if (error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred)) {
-                       if (ndp->ni_pathlen > 1)
-                               _FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
-                       break;
+       }
+       /*
+        * only come here if we fail to handle a SYMLINK...
+        * if either ni_dvp or ni_vp is non-NULL, then
+        * we need to drop the iocount that was picked
+        * up in the lookup routine
+        */
+out_drop:
+       if (ndp->ni_dvp)
+               vnode_put(ndp->ni_dvp);
+       if (ndp->ni_vp)
+               vnode_put(ndp->ni_vp);
+ error_out:
+       if ( (cnp->cn_flags & HASBUF) ) {
+               cnp->cn_flags &= ~HASBUF;
+               FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
+       }
+       cnp->cn_pnbuf = NULL;
+       ndp->ni_vp = NULLVP;
+       ndp->ni_dvp = NULLVP;
+       if (error == ERECYCLE){
+               /* vnode was recycled underneath us. re-drive lookup to start at 
+                  the beginning again, since recycling invalidated last lookup*/
+               ndp->ni_cnd.cn_flags = cnpflags;
+               ndp->ni_dvp = usedvp;
+               goto vnode_recycled;
+       }
+
+
+       return (error);
+}
+
+int            
+namei_compound_available(vnode_t dp, struct nameidata *ndp)
+{
+       if ((ndp->ni_flag & NAMEI_COMPOUNDOPEN) != 0) {
+               return vnode_compound_open_available(dp);
+       }
+
+       return 0;
+}
+int
+lookup_authorize_search(vnode_t dp, struct componentname *cnp, int dp_authorized_in_cache, vfs_context_t ctx)
+{
+       int error;
+
+       if (!dp_authorized_in_cache) {
+               error = vnode_authorize(dp, NULL, KAUTH_VNODE_SEARCH, ctx);
+               if (error)
+                       return error;
+       }
+#if CONFIG_MACF
+       error = mac_vnode_check_lookup(ctx, dp, cnp);
+       if (error)
+               return error;
+#endif /* CONFIG_MACF */
+
+       return 0;
+}
+
+void 
+lookup_consider_update_cache(vnode_t dvp, vnode_t vp, struct componentname *cnp, int nc_generation) 
+{
+       int isdot_or_dotdot;
+       isdot_or_dotdot = (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.') || (cnp->cn_flags & ISDOTDOT);
+
+       if (vp->v_name == NULL || vp->v_parent == NULLVP) {
+               int  update_flags = 0;
+
+               if (isdot_or_dotdot == 0) {
+                       if (vp->v_name == NULL)
+                               update_flags |= VNODE_UPDATE_NAME;
+                       if (dvp != NULLVP && vp->v_parent == NULLVP)
+                               update_flags |= VNODE_UPDATE_PARENT;
+
+                       if (update_flags)
+                               vnode_update_identity(vp, dvp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, update_flags);
                }
-               linklen = MAXPATHLEN - auio.uio_resid;
-               if (linklen + ndp->ni_pathlen >= MAXPATHLEN) {
-                       if (ndp->ni_pathlen > 1)
-                               _FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
-                       error = ENAMETOOLONG;
+       }
+       if ( (cnp->cn_flags & MAKEENTRY) && (vp->v_flag & VNCACHEABLE) && LIST_FIRST(&vp->v_nclinks) == NULL) {
+               /*
+                * missing from name cache, but should
+                * be in it... this can happen if volfs
+                * causes the vnode to be created or the
+                * name cache entry got recycled but the
+                * vnode didn't...
+                * check to make sure that ni_dvp is valid
+                * cache_lookup_path may return a NULL
+                * do a quick check to see if the generation of the
+                * directory matches our snapshot... this will get
+                * rechecked behind the name cache lock, but if it
+                * already fails to match, no need to go any further
+                */
+               if (dvp != NULLVP && (nc_generation == dvp->v_nc_generation) && (!isdot_or_dotdot))
+                       cache_enter_with_gen(dvp, vp, cnp, nc_generation);
+       }
+
+}
+
+#if NAMEDRSRCFORK
+/*
+ * Can change ni_dvp and ni_vp.  On success, returns with iocounts on stream vnode (always) and
+ * data fork if requested.  On failure, returns with iocount data fork (always) and its parent directory 
+ * (if one was provided).
+ */
+int
+lookup_handle_rsrc_fork(vnode_t dp, struct nameidata *ndp, struct componentname *cnp, int wantparent, vfs_context_t ctx)
+{
+       vnode_t svp = NULLVP;
+       enum nsoperation nsop;
+       int error;
+
+       if (dp->v_type != VREG) {
+               error = ENOENT;
+               goto out;
+       }
+       switch (cnp->cn_nameiop) {
+               case DELETE:
+                       if (cnp->cn_flags & CN_ALLOWRSRCFORK) {
+                               nsop = NS_DELETE;
+                       } else {
+                               error = EPERM;
+                               goto out;
+                       }
+                       break;
+               case CREATE:
+                       if (cnp->cn_flags & CN_ALLOWRSRCFORK) {
+                               nsop = NS_CREATE;
+                       } else {
+                               error = EPERM;
+                               goto out;
+                       }
                        break;
+               case LOOKUP:
+                       /* Make sure our lookup of "/..namedfork/rsrc" is allowed. */
+                       if (cnp->cn_flags & CN_ALLOWRSRCFORK) {
+                               nsop = NS_OPEN;
+                       } else {
+                               error = EPERM;
+                               goto out;
+                       }
+                       break;
+               default:
+                       error = EPERM;
+                       goto out;
+       }
+       /* Ask the file system for the resource fork. */
+       error = vnode_getnamedstream(dp, &svp, XATTR_RESOURCEFORK_NAME, nsop, 0, ctx);
+
+       /* During a create, it OK for stream vnode to be missing. */
+       if (error == ENOATTR || error == ENOENT) {
+               error = (nsop == NS_CREATE) ? 0 : ENOENT;
+       }               
+       if (error) {
+               goto out;
+       }
+       /* The "parent" of the stream is the file. */
+       if (wantparent) {
+               if (ndp->ni_dvp) {
+#ifndef __LP64__
+                       if (ndp->ni_cnd.cn_flags & FSNODELOCKHELD) {
+                               ndp->ni_cnd.cn_flags &= ~FSNODELOCKHELD;
+                               unlock_fsnode(ndp->ni_dvp, NULL);
+                       }       
+#endif /* __LP64__ */
+                       vnode_put(ndp->ni_dvp);
                }
-               if (ndp->ni_pathlen > 1) {
-                       bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
-                       FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
-                       cnp->cn_pnbuf = cp;
-                       cnp->cn_pnlen = MAXPATHLEN;
-               } else
-                       cnp->cn_pnbuf[linklen] = '\0';
-               ndp->ni_pathlen += linklen;
-               vput(ndp->ni_vp);
-               dp = ndp->ni_dvp;
-       }
-       FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
-       vrele(ndp->ni_dvp);
-       vput(ndp->ni_vp);
-       ndp->ni_vp = NULL;
-       return (error);
+               ndp->ni_dvp = dp;
+       } else {
+               vnode_put(dp);
+       }
+       ndp->ni_vp = svp;  /* on create this may be null */
+
+       /* Restore the truncated pathname buffer (for audits). */
+       if (ndp->ni_pathlen == 1 && ndp->ni_next[0] == '\0') {
+               ndp->ni_next[0] = '/';
+       }
+       cnp->cn_flags  &= ~MAKEENTRY;
+
+       return 0;
+out:
+       return error;
+}
+#endif /* NAMEDRSRCFORK */
+
+/*
+ * iocounts in:
+ *     --One on ni_vp.  One on ni_dvp if there is more path, or we didn't come through the
+ *     cache, or we came through the cache and the caller doesn't want the parent.
+ *
+ * iocounts out:
+ *     --Leaves us in the correct state for the next step, whatever that might be.
+ *     --If we find a symlink, returns with iocounts on both ni_vp and ni_dvp.
+ *     --If we are to look up another component, then we have an iocount on ni_vp and
+ *     nothing else.  
+ *     --If we are done, returns an iocount on ni_vp, and possibly on ni_dvp depending on nameidata flags.
+ *     --In the event of an error, may return with ni_dvp NULL'ed out (in which case, iocount
+ *     was dropped).
+ */
+int            
+lookup_handle_found_vnode(struct nameidata *ndp, struct componentname *cnp, int rdonly, 
+               int vbusyflags, int *keep_going, int nc_generation,
+               int wantparent, int atroot, vfs_context_t ctx)
+{
+       vnode_t dp;
+       int error;
+       char *cp;
+
+       dp = ndp->ni_vp;
+       *keep_going = 0;
+
+       if (ndp->ni_vp == NULLVP) {
+               panic("NULL ni_vp in %s\n", __FUNCTION__);
+       }
+
+       if (atroot) {
+               goto nextname;
+       }
+
+#if CONFIG_TRIGGERS
+       if (dp->v_resolve) {
+               error = vnode_trigger_resolve(dp, ndp, ctx);
+               if (error) {
+                       goto out;
+               }
+       }
+#endif /* CONFIG_TRIGGERS */
+
+       /*
+        * Take into account any additional components consumed by
+        * the underlying filesystem.
+        */
+       if (cnp->cn_consume > 0) {
+               cnp->cn_nameptr += cnp->cn_consume;
+               ndp->ni_next += cnp->cn_consume;
+               ndp->ni_pathlen -= cnp->cn_consume;
+               cnp->cn_consume = 0;
+       } else {
+               lookup_consider_update_cache(ndp->ni_dvp, dp, cnp, nc_generation);
+       }
+
+       /*
+        * Check to see if the vnode has been mounted on...
+        * if so find the root of the mounted file system.
+        * Updates ndp->ni_vp.
+        */
+       error = lookup_traverse_mountpoints(ndp, cnp, dp, vbusyflags, ctx);
+       dp = ndp->ni_vp;
+       if (error) {
+               goto out;
+       }
+
+#if CONFIG_MACF
+       if (vfs_flags(vnode_mount(dp)) & MNT_MULTILABEL) {
+               error = vnode_label(vnode_mount(dp), NULL, dp, NULL, 0, ctx);
+               if (error)
+                       goto out;
+       }
+#endif
+
+       /*
+        * Check for symbolic link
+        */
+       if ((dp->v_type == VLNK) &&
+           ((cnp->cn_flags & FOLLOW) || (ndp->ni_flag & NAMEI_TRAILINGSLASH) || *ndp->ni_next == '/')) {
+               cnp->cn_flags |= ISSYMLINK;
+               *keep_going = 1;
+               return (0);
+       }
+
+       /*
+        * Check for bogus trailing slashes.
+        */
+       if ((ndp->ni_flag & NAMEI_TRAILINGSLASH)) {
+               if (dp->v_type != VDIR) {
+                       error = ENOTDIR;
+                       goto out;
+               }
+               ndp->ni_flag &= ~(NAMEI_TRAILINGSLASH);
+       } 
+       
+nextname:
+       /*
+        * Not a symbolic link.  If more pathname,
+        * continue at next component, else return.
+        *
+        * Definitely have a dvp if there's another slash 
+        */
+       if (*ndp->ni_next == '/') {
+               cnp->cn_nameptr = ndp->ni_next + 1;
+               ndp->ni_pathlen--;
+               while (*cnp->cn_nameptr == '/') {
+                       cnp->cn_nameptr++;
+                       ndp->ni_pathlen--;
+               }
+
+               cp = cnp->cn_nameptr;
+               vnode_put(ndp->ni_dvp);
+               ndp->ni_dvp = NULLVP;
+
+               if (*cp == '\0') {
+                       goto emptyname;
+               }
+
+               *keep_going = 1;
+               return 0;
+       }
+                                 
+       /*
+        * Disallow directory write attempts on read-only file systems.
+        */
+       if (rdonly &&
+           (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
+               error = EROFS;
+               goto out;
+       }
+       
+       /* If SAVESTART is set, we should have a dvp */
+       if (cnp->cn_flags & SAVESTART) {
+               /*      
+                * note that we already hold a reference
+                * on both dp and ni_dvp, but for some reason
+                * can't get another one... in this case we
+                * need to do vnode_put on dp in 'bad2'
+                */
+               if ( (vnode_get(ndp->ni_dvp)) ) {
+                       error = ENOENT;
+                       goto out;
+               }
+               ndp->ni_startdir = ndp->ni_dvp;
+       }
+       if (!wantparent && ndp->ni_dvp) {
+               vnode_put(ndp->ni_dvp);
+               ndp->ni_dvp = NULLVP;
+       }
+
+       if (cnp->cn_flags & AUDITVNPATH1)
+               AUDIT_ARG(vnpath, dp, ARG_VNODE1);
+       else if (cnp->cn_flags & AUDITVNPATH2)
+               AUDIT_ARG(vnpath, dp, ARG_VNODE2);
+
+#if NAMEDRSRCFORK
+       /*
+        * Caller wants the resource fork.
+        */
+       if ((cnp->cn_flags & CN_WANTSRSRCFORK) && (dp != NULLVP)) {
+               error = lookup_handle_rsrc_fork(dp, ndp, cnp, wantparent, ctx);
+               if (error != 0)
+                       goto out;
+
+               dp = ndp->ni_vp;
+       }
+#endif
+       if (kdebug_enable)
+               kdebug_lookup(dp, cnp);
+
+       return 0;
+
+emptyname:
+       error = lookup_handle_emptyname(ndp, cnp, wantparent);
+       if (error != 0) 
+               goto out;
+
+       return 0;
+out:
+       return error;
+
 }
 
+/*
+ * Comes in iocount on ni_vp.  May overwrite ni_dvp, but doesn't interpret incoming value.
+ */
+int 
+lookup_handle_emptyname(struct nameidata *ndp, struct componentname *cnp, int wantparent)
+{
+       vnode_t dp;
+       int error = 0;
+
+       dp = ndp->ni_vp;
+       cnp->cn_namelen = 0;
+       /*
+        * A degenerate name (e.g. / or "") which is a way of
+        * talking about a directory, e.g. like "/." or ".".
+        */
+       if (dp->v_type != VDIR) {
+               error = ENOTDIR;
+               goto out;
+       }
+       if (cnp->cn_nameiop != LOOKUP) {
+               error = EISDIR;
+               goto out;
+       }
+       if (wantparent) {
+               /*      
+                * note that we already hold a reference
+                * on dp, but for some reason can't
+                * get another one... in this case we
+                * need to do vnode_put on dp in 'bad'
+                */
+               if ( (vnode_get(dp)) ) {
+                       error = ENOENT;
+                       goto out;
+               }
+               ndp->ni_dvp = dp;
+       }
+       cnp->cn_flags &= ~ISDOTDOT;
+       cnp->cn_flags |= ISLASTCN;
+       ndp->ni_next = cnp->cn_nameptr;
+       ndp->ni_vp = dp;
+
+       if (cnp->cn_flags & AUDITVNPATH1)
+               AUDIT_ARG(vnpath, dp, ARG_VNODE1);
+       else if (cnp->cn_flags & AUDITVNPATH2)
+               AUDIT_ARG(vnpath, dp, ARG_VNODE2);
+       if (cnp->cn_flags & SAVESTART)
+               panic("lookup: SAVESTART");
+
+       return 0;
+out:
+       return error;
+}
 /*
  * Search a pathname.
  * This is a very central and rather complicated routine.
@@ -271,7 +814,7 @@ namei(ndp)
  *     identify next component of name at ndp->ni_ptr
  *     handle degenerate case where name is null string
  *     if .. and crossing mount points and on mounted filesys, find parent
- *     call VOP_LOOKUP routine for next component name
+ *     call VNOP_LOOKUP routine for next component name
  *         directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set
  *         component vnode returned in ni_vp (if it exists), locked.
  *     if result vnode is mounted on and crossing mount points,
@@ -280,129 +823,108 @@ namei(ndp)
  *     return the answer in ni_vp, locked if LOCKLEAF set
  *         if LOCKPARENT set, return locked parent in ni_dvp
  *         if WANTPARENT set, return unlocked parent in ni_dvp
+ *
+ * Returns:    0                       Success
+ *             ENOENT                  No such file or directory
+ *             EBADF                   Bad file descriptor
+ *             ENOTDIR                 Not a directory
+ *             EROFS                   Read-only file system [CREATE]
+ *             EISDIR                  Is a directory [CREATE]
+ *             cache_lookup_path:ERECYCLE  (vnode was recycled from underneath us, redrive lookup again)
+ *             vnode_authorize:EROFS
+ *             vnode_authorize:EACCES
+ *             vnode_authorize:EPERM
+ *             vnode_authorize:???
+ *             VNOP_LOOKUP:ENOENT      No such file or directory
+ *             VNOP_LOOKUP:EJUSTRETURN Restart system call (INTERNAL)
+ *             VNOP_LOOKUP:???
+ *             VFS_ROOT:ENOTSUP
+ *             VFS_ROOT:ENOENT
+ *             VFS_ROOT:???
  */
 int
-lookup(ndp)
-       register struct nameidata *ndp;
+lookup(struct nameidata *ndp)
 {
-       register char *cp;              /* pointer into pathname argument */
-       register struct vnode *dp = 0;  /* the directory we are searching */
-       struct vnode *tdp;              /* saved dp */
-       struct mount *mp;               /* mount table entry */
-       int namemax = 0;                        /* maximun number of bytes for filename returned by pathconf() */
-       int docache;                    /* == 0 do not cache last component */
+       char    *cp;            /* pointer into pathname argument */
+       vnode_t         tdp;            /* saved dp */
+       vnode_t         dp;             /* the directory we are searching */
+       int docache = 1;                /* == 0 do not cache last component */
        int wantparent;                 /* 1 => wantparent or lockparent flag */
-       int dp_unlocked = 0;    /* 1 => dp already VOP_UNLOCK()-ed */
        int rdonly;                     /* lookup read-only flag bit */
-       int trailing_slash;
+       int dp_authorized = 0;
        int error = 0;
        struct componentname *cnp = &ndp->ni_cnd;
-       struct proc *p = cnp->cn_proc;
-       int i;
+       vfs_context_t ctx = cnp->cn_context;
+       int vbusyflags = 0;
+       int nc_generation = 0;
+       vnode_t last_dp = NULLVP;
+       int keep_going;
+       int atroot;
 
        /*
         * Setup: break out flag bits into variables.
         */
+       if (cnp->cn_flags & (NOCACHE | DOWHITEOUT)) {
+               if ((cnp->cn_flags & NOCACHE) || (cnp->cn_nameiop == DELETE))
+                       docache = 0;
+       }
        wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
-       docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
-       if (cnp->cn_nameiop == DELETE ||
-           (wantparent && cnp->cn_nameiop != CREATE &&
-             cnp->cn_nameiop != LOOKUP))
-               docache = 0;
        rdonly = cnp->cn_flags & RDONLY;
-       ndp->ni_dvp = NULL;
        cnp->cn_flags &= ~ISSYMLINK;
+       cnp->cn_consume = 0;
+
        dp = ndp->ni_startdir;
        ndp->ni_startdir = NULLVP;
-       vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
 
-dirloop:
-       /*
-        * Search a new directory.
-        *
-        * The cn_hash value is for use by vfs_cache.
-        * Check pathconf for maximun length of name
-        * The last component of the filename is left accessible via
-        * cnp->cn_nameptr for callers that need the name. Callers needing
-        * the name set the SAVENAME flag. When done, they assume
-        * responsibility for freeing the pathname buffer.
-        */
-       cnp->cn_consume = 0;
-       cnp->cn_hash = 0;
-       for (cp = cnp->cn_nameptr, i=1; *cp != 0 && *cp != '/'; i++, cp++)
-               cnp->cn_hash += (unsigned char)*cp * i;
-       cnp->cn_namelen = cp - cnp->cn_nameptr;
-    if (VOP_PATHCONF(dp, _PC_NAME_MAX, &namemax))
-               namemax = NAME_MAX;
-    if (cnp->cn_namelen > namemax) {
-               error = ENAMETOOLONG;
-               goto bad;
-       }
-#ifdef NAMEI_DIAGNOSTIC
-       { char c = *cp;
-       *cp = '\0';
-       printf("{%s}: ", cnp->cn_nameptr);
-       *cp = c; }
-#endif
-       ndp->ni_pathlen -= cnp->cn_namelen;
-       ndp->ni_next = cp;
+       if ((cnp->cn_flags & CN_NBMOUNTLOOK) != 0)
+                       vbusyflags = LK_NOWAIT;
+       cp = cnp->cn_nameptr;
 
-       /*
-        * Replace multiple slashes by a single slash and trailing slashes
-        * by a null.  This must be done before VOP_LOOKUP() because some
-        * fs's don't know about trailing slashes.  Remember if there were
-        * trailing slashes to handle symlinks, existing non-directories
-        * and non-existing files that won't be directories specially later.
-        */
-       trailing_slash = 0;
-       while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) {
-               cp++;
-               ndp->ni_pathlen--;
-               if (*cp == '\0') {
-                       trailing_slash = 1;
-                       *ndp->ni_next = '\0';
+       if (*cp == '\0') {
+               if ( (vnode_getwithref(dp)) ) {
+                       dp = NULLVP;
+                       error = ENOENT;
+                       goto bad;
                }
+               ndp->ni_vp = dp;
+               error = lookup_handle_emptyname(ndp, cnp, wantparent);
+               if (error) {
+                       goto bad;
+               }
+
+               return 0;
        }
-       ndp->ni_next = cp;
+dirloop: 
+       atroot = 0;
+       ndp->ni_vp = NULLVP;
 
-       cnp->cn_flags |= MAKEENTRY;
-       if (*cp == '\0' && docache == 0)
-               cnp->cn_flags &= ~MAKEENTRY;
-       if (cnp->cn_namelen == 2 &&
-           cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
-               cnp->cn_flags |= ISDOTDOT;
-       else
-               cnp->cn_flags &= ~ISDOTDOT;
-       if (*ndp->ni_next == 0)
-               cnp->cn_flags |= ISLASTCN;
-       else
-               cnp->cn_flags &= ~ISLASTCN;
+       if ( (error = cache_lookup_path(ndp, cnp, dp, ctx, &dp_authorized, last_dp)) ) {
+               dp = NULLVP;
+               goto bad;
+       }
+       if ((cnp->cn_flags & ISLASTCN)) {
+               if (docache)
+                       cnp->cn_flags |= MAKEENTRY;
+       } else
+               cnp->cn_flags |= MAKEENTRY;
 
+       dp = ndp->ni_dvp;
 
-       /*
-        * Check for degenerate name (e.g. / or "")
-        * which is a way of talking about a directory,
-        * e.g. like "/." or ".".
-        */
-       if (cnp->cn_nameptr[0] == '\0') {
-               if (dp->v_type != VDIR) {
-                       error = ENOTDIR;
-                       goto bad;
-               }
-               if (cnp->cn_nameiop != LOOKUP) {
-                       error = EISDIR;
-                       goto bad;
-               }
-               if (wantparent) {
-                       ndp->ni_dvp = dp;
-                       VREF(dp);
-               }
-               ndp->ni_vp = dp;
-               if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF)))
-                       VOP_UNLOCK(dp, 0, p);
-               if (cnp->cn_flags & SAVESTART)
-                       panic("lookup: SAVESTART");
-               return (0);
+       if (ndp->ni_vp != NULLVP) {
+               /*
+                * cache_lookup_path returned a non-NULL ni_vp then,
+                * we're guaranteed that the dp is a VDIR, it's 
+                * been authorized, and vp is not ".."
+                *
+                * make sure we don't try to enter the name back into
+                * the cache if this vp is purged before we get to that
+                * check since we won't have serialized behind whatever
+                * activity is occurring in the FS that caused the purge
+                */
+               if (dp != NULLVP)
+                       nc_generation = dp->v_nc_generation - 1;
+
+               goto returned_from_lookup_path;
        }
 
        /*
@@ -415,27 +937,45 @@ dirloop:
         *    vnode which was mounted on so we take the
         *    .. in the other file system.
         */
-       if (cnp->cn_flags & ISDOTDOT) {
+       if ( (cnp->cn_flags & ISDOTDOT) ) {
                for (;;) {
-                       if (dp == ndp->ni_rootdir || dp == rootvnode) {
-                               ndp->ni_dvp = dp;
+                       if (dp == ndp->ni_rootdir || dp == rootvnode) {
+                               ndp->ni_dvp = dp;
                                ndp->ni_vp = dp;
-                               VREF(dp);
-                               goto nextname;
+                               /*
+                                * we're pinned at the root
+                                * we've already got one reference on 'dp'
+                                * courtesy of cache_lookup_path... take
+                                * another one for the ".."
+                                * if we fail to get the new reference, we'll
+                                * drop our original down in 'bad'
+                                */
+                               if ( (vnode_get(dp)) ) {
+                                       error = ENOENT;
+                                       goto bad;
+                               }
+                               atroot = 1;
+                               goto returned_from_lookup_path;
                        }
                        if ((dp->v_flag & VROOT) == 0 ||
                            (cnp->cn_flags & NOCROSSMOUNT))
-                               break;
+                               break;
                        if (dp->v_mount == NULL) {      /* forced umount */
-                               error = EBADF;
+                               error = EBADF;
                                goto bad;
                        }
-
                        tdp = dp;
-                       dp = dp->v_mount->mnt_vnodecovered;
-                       vput(tdp);
-                       VREF(dp);
-                       vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
+                       dp = tdp->v_mount->mnt_vnodecovered;
+
+                       vnode_put(tdp);
+
+                       if ( (vnode_getwithref(dp)) ) {
+                               dp = NULLVP;
+                               error = ENOENT;
+                               goto bad;
+                       }
+                       ndp->ni_dvp = dp;
+                       dp_authorized = 0;
                }
        }
 
@@ -443,157 +983,402 @@ dirloop:
         * We now have a segment name to search for, and a directory to search.
         */
 unionlookup:
-       ndp->ni_dvp = dp;
-       ndp->ni_vp = NULL;
-       if (error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) {
-#if DIAGNOSTIC
-               if (ndp->ni_vp != NULL)
-                       panic("leaf should be empty");
-#endif
-#ifdef NAMEI_DIAGNOSTIC
-               printf("not found\n");
-#endif
+       ndp->ni_vp = NULLVP;
+
+       if (dp->v_type != VDIR) {
+               error = ENOTDIR;
+               goto lookup_error;
+       }
+       if ( (cnp->cn_flags & DONOTAUTH) != DONOTAUTH ) {
+               error = lookup_authorize_search(dp, cnp, dp_authorized, ctx);
+               if (error) {
+                       goto lookup_error;
+               }
+       }
+
+       /*
+        * Now that we've authorized a lookup, can bail out if the filesystem
+        * will be doing a batched operation.  Return an iocount on dvp.
+        */
+#if NAMEDRSRCFORK
+       if ((cnp->cn_flags & ISLASTCN) && namei_compound_available(dp, ndp) && !(cnp->cn_flags & CN_WANTSRSRCFORK)) {
+#else 
+       if ((cnp->cn_flags & ISLASTCN) && namei_compound_available(dp, ndp)) {
+#endif /* NAMEDRSRCFORK */
+               ndp->ni_flag |= NAMEI_UNFINISHED;
+               ndp->ni_ncgeneration = dp->v_nc_generation;
+               return 0;
+       }
+
+        nc_generation = dp->v_nc_generation;
+
+       error = VNOP_LOOKUP(dp, &ndp->ni_vp, cnp, ctx);
+
+
+       if ( error ) {
+lookup_error:
                if ((error == ENOENT) &&
                    (dp->v_flag & VROOT) && (dp->v_mount != NULL) &&
                    (dp->v_mount->mnt_flag & MNT_UNION)) {
+#ifndef __LP64__
+                       if ((cnp->cn_flags & FSNODELOCKHELD)) {
+                               cnp->cn_flags &= ~FSNODELOCKHELD;
+                               unlock_fsnode(dp, NULL);
+                       }       
+#endif /* __LP64__ */
                        tdp = dp;
-                       dp = dp->v_mount->mnt_vnodecovered;
-                       vput(tdp);
-                       VREF(dp);
-                       vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
+                       dp = tdp->v_mount->mnt_vnodecovered;
+
+                       vnode_put(tdp);
+
+                       if ( (vnode_getwithref(dp)) ) {
+                               dp = NULLVP;
+                               error = ENOENT;
+                               goto bad;
+                       }
+                       ndp->ni_dvp = dp;
+                       dp_authorized = 0;
                        goto unionlookup;
                }
 
                if (error != EJUSTRETURN)
                        goto bad;
-               /*
-                * If creating and at end of pathname, then can consider
-                * allowing file to be created.
-                */
-               if (rdonly) {
-                       error = EROFS;
-                       goto bad;
-               }
-               if (*cp == '\0' && trailing_slash &&
-                       !(cnp->cn_flags & WILLBEDIR)) {
-                       error = ENOENT;
+
+               if (ndp->ni_vp != NULLVP)
+                       panic("leaf should be empty");
+
+               error = lookup_validate_creation_path(ndp);
+               if (error)
                        goto bad;
-               }
                /*
                 * We return with ni_vp NULL to indicate that the entry
                 * doesn't currently exist, leaving a pointer to the
-                * (possibly locked) directory inode in ndp->ni_dvp.
+                * referenced directory vnode in ndp->ni_dvp.
                 */
                if (cnp->cn_flags & SAVESTART) {
+                       if ( (vnode_get(ndp->ni_dvp)) ) {
+                               error = ENOENT;
+                               goto bad;
+                       }
                        ndp->ni_startdir = ndp->ni_dvp;
-                       VREF(ndp->ni_startdir);
                }
+               if (!wantparent)
+                       vnode_put(ndp->ni_dvp);
+
                if (kdebug_enable)
                        kdebug_lookup(ndp->ni_dvp, cnp);
                return (0);
        }
-#ifdef NAMEI_DIAGNOSTIC
-       printf("found\n");
-#endif
+returned_from_lookup_path:
+       /* We'll always have an iocount on ni_vp when this finishes. */
+       error = lookup_handle_found_vnode(ndp, cnp, rdonly, vbusyflags, &keep_going, nc_generation, wantparent, atroot, ctx);
+       if (error != 0) {
+               goto bad2; 
+       }
+
+       if (keep_going) {
+               dp = ndp->ni_vp;
+
+               /* namei() will handle symlinks */
+               if ((dp->v_type == VLNK) &&
+                               ((cnp->cn_flags & FOLLOW) || (ndp->ni_flag & NAMEI_TRAILINGSLASH) || *ndp->ni_next == '/')) {
+                       return 0; 
+               }
+
+               /*
+                * Otherwise, there's more path to process.  
+                * cache_lookup_path is now responsible for dropping io ref on dp
+                * when it is called again in the dirloop.  This ensures we hold
+                * a ref on dp until we complete the next round of lookup.
+                */
+               last_dp = dp;
+
+               goto dirloop;
+       }
+
+       return (0);
+bad2:
+#ifndef __LP64__
+       if ((cnp->cn_flags & FSNODELOCKHELD)) {
+               cnp->cn_flags &= ~FSNODELOCKHELD;
+               unlock_fsnode(ndp->ni_dvp, NULL);
+       }
+#endif /* __LP64__ */
+       if (ndp->ni_dvp)
+               vnode_put(ndp->ni_dvp);
+
+       vnode_put(ndp->ni_vp);
+       ndp->ni_vp = NULLVP;
+
+       if (kdebug_enable)
+               kdebug_lookup(dp, cnp);
+       return (error);
+
+bad:
+#ifndef __LP64__
+       if ((cnp->cn_flags & FSNODELOCKHELD)) {
+               cnp->cn_flags &= ~FSNODELOCKHELD;
+               unlock_fsnode(ndp->ni_dvp, NULL);
+       }       
+#endif /* __LP64__ */
+       if (dp)
+               vnode_put(dp);
+       ndp->ni_vp = NULLVP;
+
+       if (kdebug_enable)
+               kdebug_lookup(dp, cnp);
+       return (error);
+}
+
+int 
+lookup_validate_creation_path(struct nameidata *ndp)
+{
+       struct componentname *cnp = &ndp->ni_cnd;
 
        /*
-        * Take into account any additional components consumed by
-        * the underlying filesystem.
+        * If creating and at end of pathname, then can consider
+        * allowing file to be created.
         */
-       if (cnp->cn_consume > 0) {
-               cnp->cn_nameptr += cnp->cn_consume;
-               ndp->ni_next += cnp->cn_consume;
-               ndp->ni_pathlen -= cnp->cn_consume;
-               cnp->cn_consume = 0;
+       if (cnp->cn_flags & RDONLY) {
+               return EROFS;
+       }
+       if ((cnp->cn_flags & ISLASTCN) && (ndp->ni_flag & NAMEI_TRAILINGSLASH) && !(cnp->cn_flags & WILLBEDIR)) {
+               return ENOENT;
        }
+       
+       return 0;
+}
 
-       dp = ndp->ni_vp;
-       /*
-        * Check to see if the vnode has been mounted on;
-        * if so find the root of the mounted file system.
+/*
+ * Modifies only ni_vp.  Always returns with ni_vp still valid (iocount held).
+ */
+int
+lookup_traverse_mountpoints(struct nameidata *ndp, struct componentname *cnp, vnode_t dp, 
+               int vbusyflags, vfs_context_t ctx)
+{
+       mount_t mp;
+       vnode_t tdp;
+       int error = 0;
+       uthread_t uth;
+       uint32_t depth = 0;
+       int dont_cache_mp = 0;
+       vnode_t mounted_on_dp;
+       int current_mount_generation = 0;
+       
+       mounted_on_dp = dp;
+       current_mount_generation = mount_generation;
+
+       while ((dp->v_type == VDIR) && dp->v_mountedhere &&
+                       ((cnp->cn_flags & NOCROSSMOUNT) == 0)) {
+#if CONFIG_TRIGGERS
+               /*
+                * For a trigger vnode, call its resolver when crossing its mount (if requested)
+                */
+               if (dp->v_resolve) {
+                       (void) vnode_trigger_resolve(dp, ndp, ctx);
+               }
+#endif
+               vnode_lock(dp);
+
+               if ((dp->v_type == VDIR) && (mp = dp->v_mountedhere)) {
+
+                       mp->mnt_crossref++;
+                       vnode_unlock(dp);
+
+
+                       if (vfs_busy(mp, vbusyflags)) {
+                               mount_dropcrossref(mp, dp, 0);
+                               if (vbusyflags == LK_NOWAIT) {
+                                       error = ENOENT;
+                                       goto out;
+                               }
+
+                               continue;
+                       }
+
+
+                       /*
+                        * XXX - if this is the last component of the
+                        * pathname, and it's either not a lookup operation
+                        * or the NOTRIGGER flag is set for the operation,
+                        * set a uthread flag to let VFS_ROOT() for autofs
+                        * know it shouldn't trigger a mount.
+                        */
+                       uth = (struct uthread *)get_bsdthread_info(current_thread());
+                       if ((cnp->cn_flags & ISLASTCN) &&
+                                       (cnp->cn_nameiop != LOOKUP ||
+                                        (cnp->cn_flags & NOTRIGGER))) {
+                               uth->uu_notrigger = 1;
+                               dont_cache_mp = 1;
+                       }
+
+                       error = VFS_ROOT(mp, &tdp, ctx);
+                       /* XXX - clear the uthread flag */
+                       uth->uu_notrigger = 0;
+
+                       mount_dropcrossref(mp, dp, 0);
+                       vfs_unbusy(mp);
+
+                       if (error) {
+                               goto out;
+                       }
+
+                       vnode_put(dp);
+                       ndp->ni_vp = dp = tdp;
+                       depth++;
+
+#if CONFIG_TRIGGERS
+                       /*
+                        * Check if root dir is a trigger vnode
+                        */
+                       if (dp->v_resolve) {
+                               error = vnode_trigger_resolve(dp, ndp, ctx);
+                               if (error) {
+                                       goto out;
+                               }
+                       }
+#endif                 
+
+               } else { 
+                       vnode_unlock(dp);
+                       break;
+               }
+       }
+
+       if (depth && !dont_cache_mp) {
+               mp = mounted_on_dp->v_mountedhere;
+
+               if (mp) {
+                       mount_lock_spin(mp);
+                       mp->mnt_realrootvp_vid = dp->v_id;
+                       mp->mnt_realrootvp = dp;
+                       mp->mnt_generation = current_mount_generation;
+                       mount_unlock(mp);
+               }
+       }
+
+       return 0;
+
+out:
+       return error;
+}
+
+/*
+ * Takes ni_vp and ni_dvp non-NULL.  Returns with *new_dp set to the location
+ * at which to start a lookup with a resolved path, and all other iocounts dropped.
+ */
+int 
+lookup_handle_symlink(struct nameidata *ndp, vnode_t *new_dp, vfs_context_t ctx)
+{
+       int error;
+       char *cp;               /* pointer into pathname argument */
+       uio_t auio;
+       char uio_buf[ UIO_SIZEOF(1) ];
+       int need_newpathbuf;
+       u_int linklen;
+       struct componentname *cnp = &ndp->ni_cnd;
+       vnode_t dp;
+       char *tmppn;
+
+#ifndef __LP64__
+       if ((cnp->cn_flags & FSNODELOCKHELD)) {
+               cnp->cn_flags &= ~FSNODELOCKHELD;
+               unlock_fsnode(ndp->ni_dvp, NULL);
+       }       
+#endif /* __LP64__ */
+
+       if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
+               return ELOOP;
+       }
+#if CONFIG_MACF
+       if ((error = mac_vnode_check_readlink(ctx, ndp->ni_vp)) != 0)
+               return error;
+#endif /* MAC */
+       if (ndp->ni_pathlen > 1 || !(cnp->cn_flags & HASBUF))
+               need_newpathbuf = 1;
+       else
+               need_newpathbuf = 0;
+
+       if (need_newpathbuf) {
+               MALLOC_ZONE(cp, char *, MAXPATHLEN, M_NAMEI, M_WAITOK);
+               if (cp == NULL) {
+                       return ENOMEM;
+               }
+       } else {
+               cp = cnp->cn_pnbuf;
+       }
+       auio = uio_createwithbuffer(1, 0, UIO_SYSSPACE, UIO_READ, &uio_buf[0], sizeof(uio_buf));
+
+       uio_addiov(auio, CAST_USER_ADDR_T(cp), MAXPATHLEN);
+
+       error = VNOP_READLINK(ndp->ni_vp, auio, ctx);
+       if (error) {
+               if (need_newpathbuf)
+                       FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
+               return error;
+       }
+
+       /* 
+        * Safe to set unsigned with a [larger] signed type here
+        * because 0 <= uio_resid <= MAXPATHLEN and MAXPATHLEN
+        * is only 1024.
         */
-       while (dp->v_type == VDIR && (mp = dp->v_mountedhere) &&
-              (cnp->cn_flags & NOCROSSMOUNT) == 0) {
-               if (vfs_busy(mp, 0, 0, p))
-                       continue;
-               VOP_UNLOCK(dp, 0, p);
-               error = VFS_ROOT(mp, &tdp);
-               vfs_unbusy(mp, p);
-               if (error) {
-                       dp_unlocked = 1;                /* Signal error path 'dp' has already been unlocked */
-                       goto bad2;
-               };
-               vrele(dp);
-               ndp->ni_vp = dp = tdp;
+       linklen = MAXPATHLEN - (u_int)uio_resid(auio);
+       if (linklen + ndp->ni_pathlen > MAXPATHLEN) {
+               if (need_newpathbuf)
+                       FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
+
+               return ENAMETOOLONG;
        }
+       if (need_newpathbuf) {
+               long len = cnp->cn_pnlen;
+
+               tmppn = cnp->cn_pnbuf;
+               bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
+               cnp->cn_pnbuf = cp;
+               cnp->cn_pnlen = MAXPATHLEN;
+
+               if ( (cnp->cn_flags & HASBUF) )
+                       FREE_ZONE(tmppn, len, M_NAMEI);
+               else
+                       cnp->cn_flags |= HASBUF;
+       } else
+               cnp->cn_pnbuf[linklen] = '\0';
+
+       ndp->ni_pathlen += linklen;
+       cnp->cn_nameptr = cnp->cn_pnbuf;
 
        /*
-        * Check for symbolic link
+        * starting point for 'relative'
+        * symbolic link path
         */
-       if ((dp->v_type == VLNK) &&
-           ((cnp->cn_flags & FOLLOW) || trailing_slash ||
-               *ndp->ni_next == '/')) {
-               cnp->cn_flags |= ISSYMLINK;
-               return (0);
-       }
+       dp = ndp->ni_dvp;
 
        /*
-        * Check for bogus trailing slashes.
+        * get rid of references returned via 'lookup'
         */
-        if (trailing_slash && dp->v_type != VDIR) {
-               error = ENOTDIR;
-               goto bad2;
-        }
+       vnode_put(ndp->ni_vp);
+       vnode_put(ndp->ni_dvp); /* ALWAYS have a dvp for a symlink */
+
+       ndp->ni_vp = NULLVP;
+       ndp->ni_dvp = NULLVP;
 
-nextname:
        /*
-        * Not a symbolic link.  If more pathname,
-        * continue at next component, else return.
+        * Check if symbolic link restarts us at the root
         */
-       if (*ndp->ni_next == '/') {
-               cnp->cn_nameptr = ndp->ni_next;
-               while (*cnp->cn_nameptr == '/') {
+       if (*(cnp->cn_nameptr) == '/') {
+               while (*(cnp->cn_nameptr) == '/') {
                        cnp->cn_nameptr++;
                        ndp->ni_pathlen--;
                }
-               vrele(ndp->ni_dvp);
-               goto dirloop;
-       }
-                                 
-       /*
-        * Disallow directory write attempts on read-only file systems.
-        */
-       if (rdonly &&
-           (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
-               error = EROFS;
-               goto bad2;
-       }
-       if (cnp->cn_flags & SAVESTART) {
-               ndp->ni_startdir = ndp->ni_dvp;
-               VREF(ndp->ni_startdir);
+               if ((dp = ndp->ni_rootdir) == NULLVP) {
+                       return ENOENT;
+               }
        }
-       if (!wantparent)
-               vrele(ndp->ni_dvp);
-       if ((cnp->cn_flags & LOCKLEAF) == 0)
-               VOP_UNLOCK(dp, 0, p);
-       if (kdebug_enable)
-               kdebug_lookup(dp, cnp);
-       return (0);
 
-bad2:
-       if ((cnp->cn_flags & LOCKPARENT) && *ndp->ni_next == '\0')
-               VOP_UNLOCK(ndp->ni_dvp, 0, p);
-       vrele(ndp->ni_dvp);
-bad:
-       if (dp_unlocked) {
-               vrele(dp);
-       } else {
-               vput(dp);
-       };
-       ndp->ni_vp = NULL;
-       if (kdebug_enable)
-               kdebug_lookup(dp, cnp);
-       return (error);
+       *new_dp = dp;
+
+       return 0;
 }
 
 /*
@@ -601,55 +1386,31 @@ bad:
  *    Used by lookup to re-aquire things.
  */
 int
-relookup(dvp, vpp, cnp)
-       struct vnode *dvp, **vpp;
-       struct componentname *cnp;
+relookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
 {
-       struct proc *p = cnp->cn_proc;
-       struct vnode *dp = 0;           /* the directory we are searching */
-       int docache;                    /* == 0 do not cache last component */
+       struct vnode *dp = NULL;                /* the directory we are searching */
        int wantparent;                 /* 1 => wantparent or lockparent flag */
        int rdonly;                     /* lookup read-only flag bit */
        int error = 0;
 #ifdef NAMEI_DIAGNOSTIC
-       int newhash;                    /* DEBUG: check name hash */
+       int i, newhash;                 /* DEBUG: check name hash */
        char *cp;                       /* DEBUG: check name ptr/len */
 #endif
+       vfs_context_t ctx = cnp->cn_context;;
 
        /*
         * Setup: break out flag bits into variables.
         */
        wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT);
-       docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
-       if (cnp->cn_nameiop == DELETE ||
-           (wantparent && cnp->cn_nameiop != CREATE))
-               docache = 0;
        rdonly = cnp->cn_flags & RDONLY;
        cnp->cn_flags &= ~ISSYMLINK;
-       dp = dvp;
-       vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
 
-/* dirloop: */
-       /*
-        * Search a new directory.
-        *
-        * The cn_hash value is for use by vfs_cache.
-        * The last component of the filename is left accessible via
-        * cnp->cn_nameptr for callers that need the name. Callers needing
-        * the name set the SAVENAME flag. When done, they assume
-        * responsibility for freeing the pathname buffer.
-        */
-#ifdef NAMEI_DIAGNOSTIC
-       for (newhash = 0, cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++)
-               newhash += (unsigned char)*cp;
-       if (newhash != cnp->cn_hash)
-               panic("relookup: bad hash");
-       if (cnp->cn_namelen != cp - cnp->cn_nameptr)
-               panic ("relookup: bad len");
-       if (*cp != 0)
-               panic("relookup: not last component");
-       printf("{%s}: ", cnp->cn_nameptr);
-#endif
+       if (cnp->cn_flags & NOCACHE)
+               cnp->cn_flags &= ~MAKEENTRY;
+       else
+               cnp->cn_flags |= MAKEENTRY;
+
+       dp = dvp;
 
        /*
         * Check for degenerate name (e.g. / or "")
@@ -665,27 +1426,26 @@ relookup(dvp, vpp, cnp)
                        error = ENOTDIR;
                        goto bad;
                }
-               if (!(cnp->cn_flags & LOCKLEAF))
-                       VOP_UNLOCK(dp, 0, p);
+               if ( (vnode_get(dp)) ) {
+                       error = ENOENT;
+                       goto bad;
+               }
                *vpp = dp;
+
                if (cnp->cn_flags & SAVESTART)
                        panic("lookup: SAVESTART");
                return (0);
        }
-
-       if (cnp->cn_flags & ISDOTDOT)
-               panic ("relookup: lookup on dot-dot");
-
        /*
         * We now have a segment name to search for, and a directory to search.
         */
-       if (error = VOP_LOOKUP(dp, vpp, cnp)) {
+       if ( (error = VNOP_LOOKUP(dp, vpp, cnp, ctx)) ) {
+               if (error != EJUSTRETURN)
+                       goto bad;
 #if DIAGNOSTIC
                if (*vpp != NULL)
                        panic("leaf should be empty");
 #endif
-               if (error != EJUSTRETURN)
-                       goto bad;
                /*
                 * If creating and at end of pathname, then can consider
                 * allowing file to be created.
@@ -694,9 +1454,6 @@ relookup(dvp, vpp, cnp)
                        error = EROFS;
                        goto bad;
                }
-               /* ASSERT(dvp == ndp->ni_startdir) */
-               if (cnp->cn_flags & SAVESTART)
-                       VREF(dvp);
                /*
                 * We return with ni_vp NULL to indicate that the entry
                 * doesn't currently exist, leaving a pointer to the
@@ -723,89 +1480,286 @@ relookup(dvp, vpp, cnp)
                goto bad2;
        }
        /* ASSERT(dvp == ndp->ni_startdir) */
-       if (cnp->cn_flags & SAVESTART)
-               VREF(dvp);
        
-       if (!wantparent)
-               vrele(dvp);
-       if ((cnp->cn_flags & LOCKLEAF) == 0)
-               VOP_UNLOCK(dp, 0, p);
        return (0);
 
 bad2:
-       if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
-               VOP_UNLOCK(dvp, 0, p);
-       vrele(dvp);
-bad:
-       vput(dp);
+       vnode_put(dp);
+bad:   
        *vpp = NULL;
+
        return (error);
 }
 
+void
+namei_unlock_fsnode(struct nameidata *ndp) 
+{
+#ifndef __LP64__
+       if ((ndp->ni_cnd.cn_flags & FSNODELOCKHELD)) {
+               ndp->ni_cnd.cn_flags &= ~FSNODELOCKHELD;
+               unlock_fsnode(ndp->ni_dvp, NULL);
+       }       
+#else
+       (void)ndp;
+#endif /* __LP64__ */
+}
+
+/*
+ * Free pathname buffer
+ */
+void
+nameidone(struct nameidata *ndp)
+{
+       namei_unlock_fsnode(ndp);
+
+       if (ndp->ni_cnd.cn_flags & HASBUF) {
+               char *tmp = ndp->ni_cnd.cn_pnbuf;
+
+               ndp->ni_cnd.cn_pnbuf = NULL;
+               ndp->ni_cnd.cn_flags &= ~HASBUF;
+               FREE_ZONE(tmp, ndp->ni_cnd.cn_pnlen, M_NAMEI);
+       }
+}
+
 
 #define NUMPARMS 23
 
-kdebug_lookup(dp, cnp)
-        struct vnode *dp;
-       struct componentname *cnp;
+/*
+ * Log (part of) a pathname using the KERNEL_DEBUG_CONSTANT mechanism, as used
+ * by fs_usage.  The path up to and including the current component name are
+ * logged.  Up to NUMPARMS*4 bytes of pathname will be logged.  If the path
+ * to be logged is longer than that, then the last NUMPARMS*4 bytes are logged.
+ * That is, the truncation removes the leading portion of the path.
+ *
+ * The logging is done via multiple KERNEL_DEBUG_CONSTANT calls.  The first one
+ * is marked with DBG_FUNC_START.  The last one is marked with DBG_FUNC_END
+ * (in addition to DBG_FUNC_START if it is also the first).  There may be
+ * intermediate ones with neither DBG_FUNC_START nor DBG_FUNC_END.
+ *
+ * The first KERNEL_DEBUG_CONSTANT passes the vnode pointer and 12 bytes of
+ * pathname.  The remaining KERNEL_DEBUG_CONSTANT calls add 16 bytes of pathname
+ * each.  The minimum number of KERNEL_DEBUG_CONSTANT calls required to pass
+ * the path are used.  Any excess padding in the final KERNEL_DEBUG_CONSTANT
+ * (because not all of the 12 or 16 bytes are needed for the remainder of the
+ * path) is set to zero bytes, or '>' if there is more path beyond the
+ * current component name (usually because an intermediate component was not
+ * found).
+ *
+ * NOTE: If the path length is greater than NUMPARMS*4, or is not of the form
+ * 12+N*16, there will be no padding.
+ *
+ * TODO: If there is more path beyond the current component name, should we
+ * force some padding?  For example, a lookup for /foo_bar_baz/spam that
+ * fails because /foo_bar_baz is not found will only log "/foo_bar_baz", with
+ * no '>' padding.  But /foo_bar/spam would log "/foo_bar>>>>".
+ */
+#if !defined(NO_KDEBUG)
+static void
+kdebug_lookup(struct vnode *dp, struct componentname *cnp)
 {
-        register int i, n;
-       register int dbg_namelen;
-       register int save_dbg_namelen;
-       register char *dbg_nameptr;
+       unsigned int i;
+       int code;
+       int dbg_namelen;
+       char *dbg_nameptr;
        long dbg_parms[NUMPARMS];
-       char dbg_buf[4];
-       static char *dbg_filler = ">>>>";
 
        /* Collect the pathname for tracing */
        dbg_namelen = (cnp->cn_nameptr - cnp->cn_pnbuf) + cnp->cn_namelen;
        dbg_nameptr = cnp->cn_nameptr + cnp->cn_namelen;
 
-       if (dbg_namelen > sizeof(dbg_parms))
-           dbg_namelen = sizeof(dbg_parms);
+       if (dbg_namelen > (int)sizeof(dbg_parms))
+               dbg_namelen = sizeof(dbg_parms);
        dbg_nameptr -= dbg_namelen;
-       save_dbg_namelen = dbg_namelen;
+       
+       /* Copy the (possibly truncated) path itself */
+       memcpy(dbg_parms, dbg_nameptr, dbg_namelen);
+       
+       /* Pad with '\0' or '>' */
+       if (dbg_namelen < (int)sizeof(dbg_parms)) {
+               memset((char *)dbg_parms + dbg_namelen,
+                      *(cnp->cn_nameptr + cnp->cn_namelen) ? '>' : 0,
+                      sizeof(dbg_parms) - dbg_namelen);
+       }
+       
+       /*
+        * In the event that we collect multiple, consecutive pathname
+        * entries, we must mark the start of the path's string and the end.
+        */
+       code = (FSDBG_CODE(DBG_FSRW,36)) | DBG_FUNC_START;
+
+       if (dbg_namelen <= 12)
+               code |= DBG_FUNC_END;
+
+       KERNEL_DEBUG_CONSTANT(code, dp, dbg_parms[0], dbg_parms[1], dbg_parms[2], 0);
+
+       code &= ~DBG_FUNC_START;
+
+       for (i=3, dbg_namelen -= 12; dbg_namelen > 0; i+=4, dbg_namelen -= 16) {
+               if (dbg_namelen <= 16)
+                       code |= DBG_FUNC_END;
+
+               KERNEL_DEBUG_CONSTANT(code, dbg_parms[i], dbg_parms[i+1], dbg_parms[i+2], dbg_parms[i+3], 0);
+       }
+}
+#else /* NO_KDEBUG */
+static void
+kdebug_lookup(struct vnode *dp __unused, struct componentname *cnp __unused)
+{
+}
+#endif /* NO_KDEBUG */
+
+int
+vfs_getbyid(fsid_t *fsid, ino64_t ino, vnode_t *vpp, vfs_context_t ctx)
+{
+       mount_t mp;
+       int error;
+       
+       mp = mount_lookupby_volfsid(fsid->val[0], 1);
+       if (mp == NULL) {
+               return EINVAL;
+       }
+
+       /* Get the target vnode. */
+       if (ino == 2) {
+               error = VFS_ROOT(mp, vpp, ctx);
+       } else {
+               error = VFS_VGET(mp, ino, vpp, ctx);
+       }
+
+       vfs_unbusy(mp);
+       return error;
+}
+/*
+ * Obtain the real path from a legacy volfs style path.
+ *
+ * Valid formats of input path:
+ *
+ *     "555/@"
+ *     "555/2"
+ *     "555/123456"
+ *     "555/123456/foobar"
+ *
+ * Where:
+ *     555 represents the volfs file system id
+ *     '@' and '2' are aliases to the root of a file system
+ *     123456 represents a file id
+ *     "foobar" represents a file name
+ */
+#if CONFIG_VOLFS
+static int
+vfs_getrealpath(const char * path, char * realpath, size_t bufsize, vfs_context_t ctx)
+{
+       vnode_t vp;
+       struct mount *mp = NULL;
+       char  *str;
+       char ch;
+       uint32_t  id;
+       ino64_t ino;
+       int error;
+       int length;
+
+       /* Get file system id and move str to next component. */
+       id = strtoul(path, &str, 10);
+       if (id == 0 || str[0] != '/') {
+               return (EINVAL);
+       }
+       while (*str == '/') {
+               str++;
+       }
+       ch = *str;
+
+       mp = mount_lookupby_volfsid(id, 1);
+       if (mp == NULL) {
+               return (EINVAL);  /* unexpected failure */
+       }
+       /* Check for an alias to a file system root. */
+       if (ch == '@' && str[1] == '\0') {
+               ino = 2;
+               str++;
+       } else {
+               /* Get file id and move str to next component. */
+           ino = strtouq(str, &str, 10);
+       }
+
+       /* Get the target vnode. */
+       if (ino == 2) {
+               error = VFS_ROOT(mp, &vp, ctx);
+       } else {
+               error = VFS_VGET(mp, ino, &vp, ctx);
+       }
+       vfs_unbusy(mp);
+       if (error) {
+               goto out;
+       }
+       realpath[0] = '\0';
 
-       i = 0;
+       /* Get the absolute path to this vnode. */
+       error = build_path(vp, realpath, bufsize, &length, 0, ctx);
+       vnode_put(vp);
 
-       while (dbg_namelen > 0) {
-           if (dbg_namelen >= 4) {
-               dbg_parms[i++] = *(long *)dbg_nameptr;
-               dbg_nameptr += sizeof(long);
-               dbg_namelen -= sizeof(long);
-           } else {
-               for (n = 0; n < dbg_namelen; n++)
-                   dbg_buf[n] = *dbg_nameptr++;
-               while (n <= 3) {
-                   if (*dbg_nameptr)
-                       dbg_buf[n++] = '>';
-                   else
-                       dbg_buf[n++] = 0;
+       if (error == 0 && *str != '\0') {
+               int attempt = strlcat(realpath, str, MAXPATHLEN);
+               if (attempt > MAXPATHLEN){
+                       error = ENAMETOOLONG;
                }
-               dbg_parms[i++] = *(long *)&dbg_buf[0];
+       }
+out:
+       return (error);
+}
+#endif
 
-               break;
-           }
+void
+lookup_compound_vnop_post_hook(int error, vnode_t dvp, vnode_t vp, struct nameidata *ndp, int did_create)
+{
+       if (error == 0 && vp == NULLVP) {
+               panic("NULL vp with error == 0.\n");
+       }
+
+       /* 
+        * We don't want to do any of this if we didn't use the compound vnop
+        * to perform the lookup... i.e. if we're allowing and using the legacy pattern,
+        * where we did a full lookup.
+        */
+       if ((ndp->ni_flag & NAMEI_COMPOUND_OP_MASK) == 0) {
+               return;
        }
-       while (i < NUMPARMS) {
-           if (*dbg_nameptr)
-               dbg_parms[i++] = *(long *)dbg_filler;
-           else
-               dbg_parms[i++] = 0;
+
+       /* 
+        * If we're going to continue the lookup, we'll handle
+        * all lookup-related updates at that time.
+        */
+       if (error == EKEEPLOOKING) {
+               return;
        }
 
        /*
-         In the event that we collect multiple, consecutive pathname
-         entries, we must mark the start of the path's string.
-       */
-       KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW,36)) | DBG_FUNC_START,
-                             dp, dbg_parms[0], dbg_parms[1], dbg_parms[2], 0);
-
-       for (dbg_namelen = save_dbg_namelen-12, i=3;
-            dbg_namelen > 0;
-            dbg_namelen -=(4 * sizeof(long)), i+= 4)
-         {
-           KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW,36)) | DBG_FUNC_NONE,
-                                 dbg_parms[i], dbg_parms[i+1], dbg_parms[i+2], dbg_parms[i+3], 0);
-         }
+        * Only audit or update cache for *found* vnodes.  For creation
+        * neither would happen in the non-compound-vnop case.
+        */
+       if ((vp != NULLVP) && !did_create) {
+               /* 
+                * If MAKEENTRY isn't set, and we've done a successful compound VNOP, 
+                * then we certainly don't want to update cache or identity.
+                */
+               if ((error != 0) || (ndp->ni_cnd.cn_flags & MAKEENTRY)) {
+                       lookup_consider_update_cache(dvp, vp, &ndp->ni_cnd, ndp->ni_ncgeneration);
+               }
+               if (ndp->ni_cnd.cn_flags & AUDITVNPATH1)
+                       AUDIT_ARG(vnpath, vp, ARG_VNODE1);
+               else if (ndp->ni_cnd.cn_flags & AUDITVNPATH2)
+                       AUDIT_ARG(vnpath, vp, ARG_VNODE2);
+       }
+
+       /* 
+        * If you created (whether you opened or not), cut a lookup tracepoint 
+        * for the parent dir (as would happen without a compound vnop).  Note: we may need
+        * a vnode despite failure in this case!
+        *
+        * If you did not create:
+        *      Found child (succeeded or not): cut a tracepoint for the child.  
+        *      Did not find child: cut a tracepoint with the parent.
+        */
+       if (kdebug_enable) {
+               kdebug_lookup(vp ? vp : dvp, &ndp->ni_cnd); 
+       }
 }