Fix "ls: not found" problem during buildworld. mdate.sh script

[dragonfly.git] / sys / kern / vfs_default.c

/*
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed
 * to Berkeley by John Heidemann of the UCLA Ficus project.
 *
 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *
 * $FreeBSD: src/sys/kern/vfs_default.c,v 1.28.2.7 2003/01/10 18:23:26 bde Exp $
 * $DragonFly: src/sys/kern/vfs_default.c,v 1.29 2006/02/17 19:18:06 dillon Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/nlookup.h>
#include <sys/poll.h>
#include <sys/mountctl.h>

#include <machine/limits.h>

#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vnode_pager.h>

static int      vop_nolookup (struct vop_old_lookup_args *);
static int      vop_nostrategy (struct vop_strategy_args *);

/*
 * This vnode table stores what we want to do if the filesystem doesn't
 * implement a particular VOP.
 *
 * If there is no specific entry here, we will return EOPNOTSUPP.
 */
struct vop_ops *default_vnode_vops;
static struct vnodeopv_entry_desc default_vnodeop_entries[] = {
        { &vop_default_desc,            vop_eopnotsupp },
        { &vop_advlock_desc,            vop_einval },
        { &vop_bwrite_desc,             (void *) vop_stdbwrite },
        { &vop_close_desc,              vop_null },
        { &vop_createvobject_desc,      (void *) vop_stdcreatevobject },
        { &vop_destroyvobject_desc,     (void *) vop_stddestroyvobject },
        { &vop_fsync_desc,              vop_null },
        { &vop_getvobject_desc,         (void *) vop_stdgetvobject },
        { &vop_ioctl_desc,              vop_enotty },
        { &vop_islocked_desc,           (void *) vop_stdislocked },
        { &vop_lease_desc,              vop_null },
        { &vop_lock_desc,               (void *) vop_stdlock },
        { &vop_mmap_desc,               vop_einval },
        { &vop_old_lookup_desc,         (void *) vop_nolookup },
        { &vop_open_desc,               vop_null },
        { &vop_pathconf_desc,           vop_einval },
        { &vop_poll_desc,               (void *) vop_nopoll },
        { &vop_readlink_desc,           vop_einval },
        { &vop_reallocblks_desc,        vop_eopnotsupp },
        { &vop_revoke_desc,             (void *) vop_stdrevoke },
        { &vop_strategy_desc,           (void *) vop_nostrategy },
        { &vop_unlock_desc,             (void *) vop_stdunlock },
        { &vop_getacl_desc,             vop_eopnotsupp },
        { &vop_setacl_desc,             vop_eopnotsupp },
        { &vop_aclcheck_desc,           vop_eopnotsupp },
        { &vop_getextattr_desc,         vop_eopnotsupp },
        { &vop_setextattr_desc,         vop_eopnotsupp },
        { &vop_nresolve_desc,           (void *) vop_compat_nresolve },
        { &vop_nlookupdotdot_desc,      (void *) vop_compat_nlookupdotdot },
        { &vop_ncreate_desc,            (void *) vop_compat_ncreate },
        { &vop_nmkdir_desc,             (void *) vop_compat_nmkdir },
        { &vop_nmknod_desc,             (void *) vop_compat_nmknod },
        { &vop_nlink_desc,              (void *) vop_compat_nlink },
        { &vop_nsymlink_desc,           (void *) vop_compat_nsymlink },
        { &vop_nwhiteout_desc,          (void *) vop_compat_nwhiteout },
        { &vop_nremove_desc,            (void *) vop_compat_nremove },
        { &vop_nrmdir_desc,             (void *) vop_compat_nrmdir },
        { &vop_nrename_desc,            (void *) vop_compat_nrename },
        { &vop_mountctl_desc,           (void *) journal_mountctl },
        { NULL, NULL }
};

static struct vnodeopv_desc default_vnodeop_opv_desc =
        { &default_vnode_vops, default_vnodeop_entries, 0 };

VNODEOP_SET(default_vnodeop_opv_desc);

int
vop_eopnotsupp(struct vop_generic_args *ap)
{
        return (EOPNOTSUPP);
}

int
vop_ebadf(struct vop_generic_args *ap)
{
        return (EBADF);
}

int
vop_enotty(struct vop_generic_args *ap)
{
        return (ENOTTY);
}

int
vop_einval(struct vop_generic_args *ap)
{
        return (EINVAL);
}

int
vop_null(struct vop_generic_args *ap)
{
        return (0);
}

int
vop_defaultop(struct vop_generic_args *ap)
{
        return (VOCALL(default_vnode_vops, ap));
}

int
vop_panic(struct vop_generic_args *ap)
{

        panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
}

/*
 * vop_compat_resolve { struct namecache *a_ncp }       XXX STOPGAP FUNCTION
 *
 * XXX OLD API ROUTINE!  WHEN ALL VFSs HAVE BEEN CLEANED UP THIS PROCEDURE
 * WILL BE REMOVED.  This procedure exists for all VFSs which have not
 * yet implemented VOP_NRESOLVE().  It converts VOP_NRESOLVE() into a 
 * vop_old_lookup() and does appropriate translations.
 *
 * Resolve a ncp for VFSs which do not support the VOP.  Eventually all
 * VFSs will support this VOP and this routine can be removed, since
 * VOP_NRESOLVE() is far less complex then the older LOOKUP/CACHEDLOOKUP
 * API.
 *
 * A locked ncp is passed in to be resolved.  The NCP is resolved by
 * figuring out the vnode (if any) and calling cache_setvp() to attach the
 * vnode to the entry.  If the entry represents a non-existant node then
 * cache_setvp() is called with a NULL vnode to resolve the entry into a
 * negative cache entry.  No vnode locks are retained and the
 * ncp is left locked on return.
 *
 * The ncp will NEVER represent "", "." or "..", or contain any slashes.
 *
 * There is a potential directory and vnode interlock.   The lock order
 * requirement is: namecache, governing directory, resolved vnode.
 */
int
vop_compat_nresolve(struct vop_nresolve_args *ap)
{
        int error;
        struct vnode *dvp;
        struct vnode *vp;
        struct namecache *ncp;
        struct componentname cnp;

        ncp = ap->a_ncp;        /* locked namecache node */
        if (ncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                return(EPERM);
        if (ncp->nc_parent == NULL)
                return(EPERM);
        if ((dvp = ncp->nc_parent->nc_vp) == NULL)
                return(EPERM);

        /*
         * UFS currently stores all sorts of side effects, including a loop
         * variable, in the directory inode.  That needs to be fixed and the
         * other VFS's audited before we can switch to LK_SHARED.
         */
        if ((error = vget(dvp, LK_EXCLUSIVE, curthread)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        ncp, ncp->nc_name);
                return(EAGAIN);
        }

        bzero(&cnp, sizeof(cnp));
        cnp.cn_nameiop = NAMEI_LOOKUP;
        cnp.cn_flags = 0;
        cnp.cn_nameptr = ncp->nc_name;
        cnp.cn_namelen = ncp->nc_nlen;
        cnp.cn_cred = ap->a_cred;
        cnp.cn_td = curthread; /* XXX */

        /*
         * vop_old_lookup() always returns vp locked.  dvp may or may not be
         * left locked depending on CNP_PDIRUNLOCK.
         */
        error = vop_old_lookup(ap->a_head.a_ops, dvp, &vp, &cnp);
        if (error == 0)
                VOP_UNLOCK(vp, 0, curthread);
        if ((cnp.cn_flags & CNP_PDIRUNLOCK) == 0)
                VOP_UNLOCK(dvp, 0, curthread);
        if ((ncp->nc_flag & NCF_UNRESOLVED) == 0) {
                /* was resolved by another process while we were unlocked */
                if (error == 0)
                        vrele(vp);
        } else if (error == 0) {
                KKASSERT(vp != NULL);
                cache_setvp(ncp, vp);
                vrele(vp);
        } else if (error == ENOENT) {
                KKASSERT(vp == NULL);
                if (cnp.cn_flags & CNP_ISWHITEOUT)
                        ncp->nc_flag |= NCF_WHITEOUT;
                cache_setvp(ncp, NULL);
        }
        vrele(dvp);
        return (error);
}

/*
 * vop_compat_nlookupdotdot { struct vnode *a_dvp,
 *                      struct vnode **a_vpp,
 *                      struct ucred *a_cred }
 *
 * Lookup the vnode representing the parent directory of the specified
 * directory vnode.  a_dvp should not be locked.  If no error occurs *a_vpp
 * will contained the parent vnode, locked and refd, else *a_vpp will be NULL.
 *
 * This function is designed to aid NFS server-side operations and is
 * used by cache_fromdvp() to create a consistent, connected namecache
 * topology.
 *
 * As part of the NEW API work, VFSs will first split their CNP_ISDOTDOT
 * code out from their *_lookup() and create *_nlookupdotdot().  Then as time
 * permits VFSs will implement the remaining *_n*() calls and finally get
 * rid of their *_lookup() call.
 */
int
vop_compat_nlookupdotdot(struct vop_nlookupdotdot_args *ap)
{
        struct componentname cnp;
        int error;

        /*
         * UFS currently stores all sorts of side effects, including a loop
         * variable, in the directory inode.  That needs to be fixed and the
         * other VFS's audited before we can switch to LK_SHARED.
         */
        *ap->a_vpp = NULL;
        if ((error = vget(ap->a_dvp, LK_EXCLUSIVE, curthread)) != 0)
                return (error);
        if (ap->a_dvp->v_type != VDIR) {
                vput(ap->a_dvp);
                return (ENOTDIR);
        }

        bzero(&cnp, sizeof(cnp));
        cnp.cn_nameiop = NAMEI_LOOKUP;
        cnp.cn_flags = CNP_ISDOTDOT;
        cnp.cn_nameptr = "..";
        cnp.cn_namelen = 2;
        cnp.cn_cred = ap->a_cred;
        cnp.cn_td = curthread; /* XXX */

        /*
         * vop_old_lookup() always returns vp locked.  dvp may or may not be
         * left locked depending on CNP_PDIRUNLOCK.
         */
        error = vop_old_lookup(ap->a_head.a_ops, ap->a_dvp, ap->a_vpp, &cnp);
        if (error == 0)
                VOP_UNLOCK(*ap->a_vpp, 0, curthread);
        if (cnp.cn_flags & CNP_PDIRUNLOCK)
                vrele(ap->a_dvp);
        else
                vput(ap->a_dvp);
        return (error);
}

/*
 * vop_compat_ncreate { struct namecache *a_ncp,        XXX STOPGAP FUNCTION
 *                      struct vnode *a_vpp,
 *                      struct ucred *a_cred,
 *                      struct vattr *a_vap }
 *
 * Create a file as specified by a_vap.  Compatibility requires us to issue
 * the appropriate VOP_OLD_LOOKUP before we issue VOP_OLD_CREATE in order
 * to setup the directory inode's i_offset and i_count (e.g. in UFS).
 */
int
vop_compat_ncreate(struct vop_ncreate_args *ap)
{
        struct thread *td = curthread;
        struct componentname cnp;
        struct namecache *ncp;
        struct vnode *dvp;
        int error;

        /*
         * Sanity checks, get a locked directory vnode.
         */
        ncp = ap->a_ncp;                /* locked namecache node */
        if (ncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                return(EPERM);
        if (ncp->nc_parent == NULL)
                return(EPERM);
        if ((dvp = ncp->nc_parent->nc_vp) == NULL)
                return(EPERM);

        if ((error = vget(dvp, LK_EXCLUSIVE, td)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        ncp, ncp->nc_name);
                return(EAGAIN);
        }

        /*
         * Setup the cnp for a traditional vop_old_lookup() call.  The lookup
         * caches all information required to create the entry in the
         * directory inode.  We expect a return code of EJUSTRETURN for
         * the CREATE case.  The cnp must simulated a saved-name situation.
         */
        bzero(&cnp, sizeof(cnp));
        cnp.cn_nameiop = NAMEI_CREATE;
        cnp.cn_flags = CNP_LOCKPARENT;
        cnp.cn_nameptr = ncp->nc_name;
        cnp.cn_namelen = ncp->nc_nlen;
        cnp.cn_cred = ap->a_cred;
        cnp.cn_td = td;
        *ap->a_vpp = NULL;

        error = vop_old_lookup(ap->a_head.a_ops, dvp, ap->a_vpp, &cnp);

        /*
         * EJUSTRETURN should be returned for this case, which means that
         * the VFS has setup the directory inode for the create.  The dvp we
         * passed in is expected to remain in a locked state.
         *
         * If the VOP_OLD_CREATE is successful we are responsible for updating
         * the cache state of the locked ncp that was passed to us.
         */
        if (error == EJUSTRETURN) {
                KKASSERT((cnp.cn_flags & CNP_PDIRUNLOCK) == 0);
                VOP_LEASE(dvp, td, ap->a_cred, LEASE_WRITE);
                error = VOP_OLD_CREATE(dvp, ap->a_vpp, &cnp, ap->a_vap);
                if (error == 0) {
                        cache_setunresolved(ncp);
                        cache_setvp(ncp, *ap->a_vpp);
                }
        } else {
                if (error == 0) {
                        vput(*ap->a_vpp);
                        *ap->a_vpp = NULL;
                        error = EEXIST;
                }
                KKASSERT(*ap->a_vpp == NULL);
        }
        if ((cnp.cn_flags & CNP_PDIRUNLOCK) == 0)
                VOP_UNLOCK(dvp, 0, td);
        vrele(dvp);
        return (error);
}

/*
 * vop_compat_nmkdir { struct namecache *a_ncp,         XXX STOPGAP FUNCTION
 *                      struct vnode *a_vpp,
 *                      struct ucred *a_cred,
 *                      struct vattr *a_vap }
 *
 * Create a directory as specified by a_vap.  Compatibility requires us to
 * issue the appropriate VOP_OLD_LOOKUP before we issue VOP_OLD_MKDIR in
 * order to setup the directory inode's i_offset and i_count (e.g. in UFS).
 */
int
vop_compat_nmkdir(struct vop_nmkdir_args *ap)
{
        struct thread *td = curthread;
        struct componentname cnp;
        struct namecache *ncp;
        struct vnode *dvp;
        int error;

        /*
         * Sanity checks, get a locked directory vnode.
         */
        ncp = ap->a_ncp;                /* locked namecache node */
        if (ncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                return(EPERM);
        if (ncp->nc_parent == NULL)
                return(EPERM);
        if ((dvp = ncp->nc_parent->nc_vp) == NULL)
                return(EPERM);

        if ((error = vget(dvp, LK_EXCLUSIVE, td)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        ncp, ncp->nc_name);
                return(EAGAIN);
        }

        /*
         * Setup the cnp for a traditional vop_old_lookup() call.  The lookup
         * caches all information required to create the entry in the
         * directory inode.  We expect a return code of EJUSTRETURN for
         * the CREATE case.  The cnp must simulated a saved-name situation.
         */
        bzero(&cnp, sizeof(cnp));
        cnp.cn_nameiop = NAMEI_CREATE;
        cnp.cn_flags = CNP_LOCKPARENT;
        cnp.cn_nameptr = ncp->nc_name;
        cnp.cn_namelen = ncp->nc_nlen;
        cnp.cn_cred = ap->a_cred;
        cnp.cn_td = td;
        *ap->a_vpp = NULL;

        error = vop_old_lookup(ap->a_head.a_ops, dvp, ap->a_vpp, &cnp);

        /*
         * EJUSTRETURN should be returned for this case, which means that
         * the VFS has setup the directory inode for the create.  The dvp we
         * passed in is expected to remain in a locked state.
         *
         * If the VOP_OLD_MKDIR is successful we are responsible for updating
         * the cache state of the locked ncp that was passed to us.
         */
        if (error == EJUSTRETURN) {
                KKASSERT((cnp.cn_flags & CNP_PDIRUNLOCK) == 0);
                VOP_LEASE(dvp, td, ap->a_cred, LEASE_WRITE);
                error = VOP_OLD_MKDIR(dvp, ap->a_vpp, &cnp, ap->a_vap);
                if (error == 0) {
                        cache_setunresolved(ncp);
                        cache_setvp(ncp, *ap->a_vpp);
                }
        } else {
                if (error == 0) {
                        vput(*ap->a_vpp);
                        *ap->a_vpp = NULL;
                        error = EEXIST;
                }
                KKASSERT(*ap->a_vpp == NULL);
        }
        if ((cnp.cn_flags & CNP_PDIRUNLOCK) == 0)
                VOP_UNLOCK(dvp, 0, td);
        vrele(dvp);
        return (error);
}

/*
 * vop_compat_nmknod { struct namecache *a_ncp,         XXX STOPGAP FUNCTION
 *                      struct vnode *a_vpp,
 *                      struct ucred *a_cred,
 *                      struct vattr *a_vap }
 *
 * Create a device or fifo node as specified by a_vap.  Compatibility requires
 * us to issue the appropriate VOP_OLD_LOOKUP before we issue VOP_OLD_MKNOD
 * in order to setup the directory inode's i_offset and i_count (e.g. in UFS).
 */
int
vop_compat_nmknod(struct vop_nmknod_args *ap)
{
        struct thread *td = curthread;
        struct componentname cnp;
        struct namecache *ncp;
        struct vnode *dvp;
        int error;

        /*
         * Sanity checks, get a locked directory vnode.
         */
        ncp = ap->a_ncp;                /* locked namecache node */
        if (ncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                return(EPERM);
        if (ncp->nc_parent == NULL)
                return(EPERM);
        if ((dvp = ncp->nc_parent->nc_vp) == NULL)
                return(EPERM);

        if ((error = vget(dvp, LK_EXCLUSIVE, td)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        ncp, ncp->nc_name);
                return(EAGAIN);
        }

        /*
         * Setup the cnp for a traditional vop_old_lookup() call.  The lookup
         * caches all information required to create the entry in the
         * directory inode.  We expect a return code of EJUSTRETURN for
         * the CREATE case.  The cnp must simulated a saved-name situation.
         */
        bzero(&cnp, sizeof(cnp));
        cnp.cn_nameiop = NAMEI_CREATE;
        cnp.cn_flags = CNP_LOCKPARENT;
        cnp.cn_nameptr = ncp->nc_name;
        cnp.cn_namelen = ncp->nc_nlen;
        cnp.cn_cred = ap->a_cred;
        cnp.cn_td = td;
        *ap->a_vpp = NULL;

        error = vop_old_lookup(ap->a_head.a_ops, dvp, ap->a_vpp, &cnp);

        /*
         * EJUSTRETURN should be returned for this case, which means that
         * the VFS has setup the directory inode for the create.  The dvp we
         * passed in is expected to remain in a locked state.
         *
         * If the VOP_OLD_MKNOD is successful we are responsible for updating
         * the cache state of the locked ncp that was passed to us.
         */
        if (error == EJUSTRETURN) {
                KKASSERT((cnp.cn_flags & CNP_PDIRUNLOCK) == 0);
                VOP_LEASE(dvp, td, ap->a_cred, LEASE_WRITE);
                error = VOP_OLD_MKNOD(dvp, ap->a_vpp, &cnp, ap->a_vap);
                if (error == 0) {
                        cache_setunresolved(ncp);
                        cache_setvp(ncp, *ap->a_vpp);
                }
        } else {
                if (error == 0) {
                        vput(*ap->a_vpp);
                        *ap->a_vpp = NULL;
                        error = EEXIST;
                }
                KKASSERT(*ap->a_vpp == NULL);
        }
        if ((cnp.cn_flags & CNP_PDIRUNLOCK) == 0)
                VOP_UNLOCK(dvp, 0, td);
        vrele(dvp);
        return (error);
}

/*
 * vop_compat_nlink { struct namecache *a_ncp,  XXX STOPGAP FUNCTION
 *                      struct vnode *a_vp,
 *                      struct ucred *a_cred }
 *
 * The passed vp is locked and represents the source.  The passed ncp is
 * locked and represents the target to create.
 */
int
vop_compat_nlink(struct vop_nlink_args *ap)
{
        struct thread *td = curthread;
        struct componentname cnp;
        struct namecache *ncp;
        struct vnode *dvp;
        struct vnode *tvp;
        int error;

        /*
         * Sanity checks, get a locked directory vnode.
         */
        ncp = ap->a_ncp;                /* locked namecache node */
        if (ncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                return(EPERM);
        if (ncp->nc_parent == NULL)
                return(EPERM);
        if ((dvp = ncp->nc_parent->nc_vp) == NULL)
                return(EPERM);

        if ((error = vget(dvp, LK_EXCLUSIVE, td)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        ncp, ncp->nc_name);
                return(EAGAIN);
        }

        /*
         * Setup the cnp for a traditional vop_old_lookup() call.  The lookup
         * caches all information required to create the entry in the
         * directory inode.  We expect a return code of EJUSTRETURN for
         * the CREATE case.  The cnp must simulated a saved-name situation.
         */
        bzero(&cnp, sizeof(cnp));
        cnp.cn_nameiop = NAMEI_CREATE;
        cnp.cn_flags = CNP_LOCKPARENT;
        cnp.cn_nameptr = ncp->nc_name;
        cnp.cn_namelen = ncp->nc_nlen;
        cnp.cn_cred = ap->a_cred;
        cnp.cn_td = td;

        tvp = NULL;
        error = vop_old_lookup(ap->a_head.a_ops, dvp, &tvp, &cnp);

        /*
         * EJUSTRETURN should be returned for this case, which means that
         * the VFS has setup the directory inode for the create.  The dvp we
         * passed in is expected to remain in a locked state.
         *
         * If the VOP_OLD_LINK is successful we are responsible for updating
         * the cache state of the locked ncp that was passed to us.
         */
        if (error == EJUSTRETURN) {
                KKASSERT((cnp.cn_flags & CNP_PDIRUNLOCK) == 0);
                VOP_LEASE(dvp, td, ap->a_cred, LEASE_WRITE);
                VOP_LEASE(ap->a_vp, td, ap->a_cred, LEASE_WRITE);
                error = VOP_OLD_LINK(dvp, ap->a_vp, &cnp);
                if (error == 0) {
                        cache_setunresolved(ncp);
                        cache_setvp(ncp, ap->a_vp);
                }
        } else {
                if (error == 0) {
                        vput(tvp);
                        error = EEXIST;
                }
        }
        if ((cnp.cn_flags & CNP_PDIRUNLOCK) == 0)
                VOP_UNLOCK(dvp, 0, td);
        vrele(dvp);
        return (error);
}

int
vop_compat_nsymlink(struct vop_nsymlink_args *ap)
{
        struct thread *td = curthread;
        struct componentname cnp;
        struct namecache *ncp;
        struct vnode *dvp;
        struct vnode *vp;
        int error;

        /*
         * Sanity checks, get a locked directory vnode.
         */
        *ap->a_vpp = NULL;
        ncp = ap->a_ncp;                /* locked namecache node */
        if (ncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                return(EPERM);
        if (ncp->nc_parent == NULL)
                return(EPERM);
        if ((dvp = ncp->nc_parent->nc_vp) == NULL)
                return(EPERM);

        if ((error = vget(dvp, LK_EXCLUSIVE, td)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        ncp, ncp->nc_name);
                return(EAGAIN);
        }

        /*
         * Setup the cnp for a traditional vop_old_lookup() call.  The lookup
         * caches all information required to create the entry in the
         * directory inode.  We expect a return code of EJUSTRETURN for
         * the CREATE case.  The cnp must simulated a saved-name situation.
         */
        bzero(&cnp, sizeof(cnp));
        cnp.cn_nameiop = NAMEI_CREATE;
        cnp.cn_flags = CNP_LOCKPARENT;
        cnp.cn_nameptr = ncp->nc_name;
        cnp.cn_namelen = ncp->nc_nlen;
        cnp.cn_cred = ap->a_cred;
        cnp.cn_td = td;

        vp = NULL;
        error = vop_old_lookup(ap->a_head.a_ops, dvp, &vp, &cnp);

        /*
         * EJUSTRETURN should be returned for this case, which means that
         * the VFS has setup the directory inode for the create.  The dvp we
         * passed in is expected to remain in a locked state.
         *
         * If the VOP_OLD_SYMLINK is successful we are responsible for updating
         * the cache state of the locked ncp that was passed to us.
         */
        if (error == EJUSTRETURN) {
                KKASSERT((cnp.cn_flags & CNP_PDIRUNLOCK) == 0);
                VOP_LEASE(dvp, td, ap->a_cred, LEASE_WRITE);
                error = VOP_OLD_SYMLINK(dvp, &vp, &cnp, ap->a_vap, ap->a_target);
                if (error == 0) {
                        cache_setunresolved(ncp);
                        cache_setvp(ncp, vp);
                        *ap->a_vpp = vp;
                }
        } else {
                if (error == 0) {
                        vput(vp);
                        vp = NULL;
                        error = EEXIST;
                }
                KKASSERT(vp == NULL);
        }
        if ((cnp.cn_flags & CNP_PDIRUNLOCK) == 0)
                VOP_UNLOCK(dvp, 0, td);
        vrele(dvp);
        return (error);
}

/*
 * vop_compat_nwhiteout { struct namecache *a_ncp,      XXX STOPGAP FUNCTION
 *                        struct ucred *a_cred,
 *                        int a_flags }
 *
 * Issie a whiteout operation (create, lookup, or delete).  Compatibility 
 * requires us to issue the appropriate VOP_OLD_LOOKUP before we issue 
 * VOP_OLD_WHITEOUT in order to setup the directory inode's i_offset and i_count
 * (e.g. in UFS) for the NAMEI_CREATE and NAMEI_DELETE ops.  For NAMEI_LOOKUP
 * no lookup is necessary.
 */
int
vop_compat_nwhiteout(struct vop_nwhiteout_args *ap)
{
        struct thread *td = curthread;
        struct componentname cnp;
        struct namecache *ncp;
        struct vnode *dvp;
        struct vnode *vp;
        int error;

        /*
         * Sanity checks, get a locked directory vnode.
         */
        ncp = ap->a_ncp;                /* locked namecache node */
        if (ncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                return(EPERM);
        if (ncp->nc_parent == NULL)
                return(EPERM);
        if ((dvp = ncp->nc_parent->nc_vp) == NULL)
                return(EPERM);

        if ((error = vget(dvp, LK_EXCLUSIVE, td)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        ncp, ncp->nc_name);
                return(EAGAIN);
        }

        /*
         * Setup the cnp for a traditional vop_old_lookup() call.  The lookup
         * caches all information required to create the entry in the
         * directory inode.  We expect a return code of EJUSTRETURN for
         * the CREATE case.  The cnp must simulated a saved-name situation.
         */
        bzero(&cnp, sizeof(cnp));
        cnp.cn_nameiop = ap->a_flags;
        cnp.cn_flags = CNP_LOCKPARENT;
        cnp.cn_nameptr = ncp->nc_name;
        cnp.cn_namelen = ncp->nc_nlen;
        cnp.cn_cred = ap->a_cred;
        cnp.cn_td = td;

        vp = NULL;

        /*
         * EJUSTRETURN should be returned for the CREATE or DELETE cases.
         * The VFS has setup the directory inode for the create.  The dvp we
         * passed in is expected to remain in a locked state.
         *
         * If the VOP_OLD_WHITEOUT is successful we are responsible for updating
         * the cache state of the locked ncp that was passed to us.
         */
        switch(ap->a_flags) {
        case NAMEI_DELETE:
                cnp.cn_flags |= CNP_DOWHITEOUT;
                /* fall through */
        case NAMEI_CREATE:
                error = vop_old_lookup(ap->a_head.a_ops, dvp, &vp, &cnp);
                if (error == EJUSTRETURN) {
                        KKASSERT((cnp.cn_flags & CNP_PDIRUNLOCK) == 0);
                        VOP_LEASE(dvp, td, ap->a_cred, LEASE_WRITE);
                        error = VOP_OLD_WHITEOUT(dvp, &cnp, ap->a_flags);
                        if (error == 0)
                                cache_setunresolved(ncp);
                } else {
                        if (error == 0) {
                                vput(vp);
                                vp = NULL;
                                error = EEXIST;
                        }
                        KKASSERT(vp == NULL);
                }
                break;
        case NAMEI_LOOKUP:
                error = VOP_OLD_WHITEOUT(dvp, NULL, ap->a_flags);
                break;
        default:
                error = EINVAL;
                break;
        }
        if ((cnp.cn_flags & CNP_PDIRUNLOCK) == 0)
                VOP_UNLOCK(dvp, 0, td);
        vrele(dvp);
        return (error);
}


/*
 * vop_compat_nremove { struct namecache *a_ncp,        XXX STOPGAP FUNCTION
 *                        struct ucred *a_cred }
 */
int
vop_compat_nremove(struct vop_nremove_args *ap)
{
        struct thread *td = curthread;
        struct componentname cnp;
        struct namecache *ncp;
        struct vnode *dvp;
        struct vnode *vp;
        int error;

        /*
         * Sanity checks, get a locked directory vnode.
         */
        ncp = ap->a_ncp;                /* locked namecache node */
        if (ncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                return(EPERM);
        if (ncp->nc_parent == NULL)
                return(EPERM);
        if ((dvp = ncp->nc_parent->nc_vp) == NULL)
                return(EPERM);

        if ((error = vget(dvp, LK_EXCLUSIVE, td)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        ncp, ncp->nc_name);
                return(EAGAIN);
        }

        /*
         * Setup the cnp for a traditional vop_old_lookup() call.  The lookup
         * caches all information required to delete the entry in the
         * directory inode.  We expect a return code of 0 for the DELETE
         * case (meaning that a vp has been found).  The cnp must simulated
         * a saved-name situation.
         */
        bzero(&cnp, sizeof(cnp));
        cnp.cn_nameiop = NAMEI_DELETE;
        cnp.cn_flags = CNP_LOCKPARENT;
        cnp.cn_nameptr = ncp->nc_name;
        cnp.cn_namelen = ncp->nc_nlen;
        cnp.cn_cred = ap->a_cred;
        cnp.cn_td = td;

        /*
         * The vnode must be a directory and must not represent the
         * current directory.
         */
        vp = NULL;
        error = vop_old_lookup(ap->a_head.a_ops, dvp, &vp, &cnp);
        if (error == 0 && vp->v_type == VDIR)
                error = EPERM;
        if (error == 0) {
                KKASSERT((cnp.cn_flags & CNP_PDIRUNLOCK) == 0);
                VOP_LEASE(dvp, td, ap->a_cred, LEASE_WRITE);
                VOP_LEASE(vp, td, ap->a_cred, LEASE_WRITE);
                error = VOP_OLD_REMOVE(dvp, vp, &cnp);
                if (error == 0) {
                        cache_setunresolved(ncp);
                        cache_setvp(ncp, NULL);
                }
        }
        if (vp) {
                if (dvp == vp)
                        vrele(vp);
                else    
                        vput(vp);
        }
        if ((cnp.cn_flags & CNP_PDIRUNLOCK) == 0)
                VOP_UNLOCK(dvp, 0, td);
        vrele(dvp);
        return (error);
}

/*
 * vop_compat_nrmdir { struct namecache *a_ncp,         XXX STOPGAP FUNCTION
 *                        struct ucred *a_cred }
 */
int
vop_compat_nrmdir(struct vop_nrmdir_args *ap)
{
        struct thread *td = curthread;
        struct componentname cnp;
        struct namecache *ncp;
        struct vnode *dvp;
        struct vnode *vp;
        int error;

        /*
         * Sanity checks, get a locked directory vnode.
         */
        ncp = ap->a_ncp;                /* locked namecache node */
        if (ncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                return(EPERM);
        if (ncp->nc_parent == NULL)
                return(EPERM);
        if ((dvp = ncp->nc_parent->nc_vp) == NULL)
                return(EPERM);

        if ((error = vget(dvp, LK_EXCLUSIVE, td)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        ncp, ncp->nc_name);
                return(EAGAIN);
        }

        /*
         * Setup the cnp for a traditional vop_old_lookup() call.  The lookup
         * caches all information required to delete the entry in the
         * directory inode.  We expect a return code of 0 for the DELETE
         * case (meaning that a vp has been found).  The cnp must simulated
         * a saved-name situation.
         */
        bzero(&cnp, sizeof(cnp));
        cnp.cn_nameiop = NAMEI_DELETE;
        cnp.cn_flags = CNP_LOCKPARENT;
        cnp.cn_nameptr = ncp->nc_name;
        cnp.cn_namelen = ncp->nc_nlen;
        cnp.cn_cred = ap->a_cred;
        cnp.cn_td = td;

        /*
         * The vnode must be a directory and must not represent the
         * current directory.
         */
        vp = NULL;
        error = vop_old_lookup(ap->a_head.a_ops, dvp, &vp, &cnp);
        if (error == 0 && vp->v_type != VDIR)
                error = ENOTDIR;
        if (error == 0 && vp == dvp)
                error = EINVAL;
        if (error == 0 && (vp->v_flag & VROOT))
                error = EBUSY;
        if (error == 0) {
                KKASSERT((cnp.cn_flags & CNP_PDIRUNLOCK) == 0);
                VOP_LEASE(dvp, td, ap->a_cred, LEASE_WRITE);
                VOP_LEASE(vp, td, ap->a_cred, LEASE_WRITE);
                error = VOP_OLD_RMDIR(dvp, vp, &cnp);

                /*
                 * Note that this invalidation will cause any process
                 * currently CD'd into the directory being removed to be
                 * disconnected from the topology and not be able to ".."
                 * back out.
                 */
                if (error == 0)
                        cache_inval(ncp, CINV_DESTROY);
        }
        if (vp) {
                if (dvp == vp)
                        vrele(vp);
                else    
                        vput(vp);
        }
        if ((cnp.cn_flags & CNP_PDIRUNLOCK) == 0)
                VOP_UNLOCK(dvp, 0, td);
        vrele(dvp);
        return (error);
}

/*
 * vop_compat_nrename { struct namecache *a_fncp,       XXX STOPGAP FUNCTION
 *                      struct namecache *a_tncp,
 *                      struct ucred *a_cred }
 *
 * This is a fairly difficult procedure.  The old VOP_OLD_RENAME requires that
 * the source directory and vnode be unlocked and the target directory and
 * vnode (if it exists) be locked.  All arguments will be vrele'd and 
 * the targets will also be unlocked regardless of the return code.
 */
int
vop_compat_nrename(struct vop_nrename_args *ap)
{
        struct thread *td = curthread;
        struct componentname fcnp;
        struct componentname tcnp;
        struct namecache *fncp;
        struct namecache *tncp;
        struct vnode *fdvp, *fvp;
        struct vnode *tdvp, *tvp;
        int error;

        /*
         * Sanity checks, get referenced vnodes representing the source.
         */
        fncp = ap->a_fncp;              /* locked namecache node */
        if (fncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                return(EPERM);
        if (fncp->nc_parent == NULL)
                return(EPERM);
        if ((fdvp = fncp->nc_parent->nc_vp) == NULL)
                return(EPERM);

        /*
         * Temporarily lock the source directory and lookup in DELETE mode to
         * check permissions.  XXX delete permissions should have been
         * checked by nlookup(), we need to add NLC_DELETE for delete
         * checking.  It is unclear whether VFS's require the directory setup
         * info NAMEI_DELETE causes to be stored in the fdvp's inode, but
         * since it isn't locked and since UFS always does a relookup of
         * the source, it is believed that the only side effect that matters
         * is the permissions check.
         */
        if ((error = vget(fdvp, LK_EXCLUSIVE, td)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        fncp, fncp->nc_name);
                return(EAGAIN);
        }

        bzero(&fcnp, sizeof(fcnp));
        fcnp.cn_nameiop = NAMEI_DELETE;
        fcnp.cn_flags = CNP_LOCKPARENT;
        fcnp.cn_nameptr = fncp->nc_name;
        fcnp.cn_namelen = fncp->nc_nlen;
        fcnp.cn_cred = ap->a_cred;
        fcnp.cn_td = td;

        /*
         * note: vop_old_lookup (i.e. VOP_OLD_LOOKUP) always returns a locked
         * fvp.
         */
        fvp = NULL;
        error = vop_old_lookup(ap->a_head.a_ops, fdvp, &fvp, &fcnp);
        if (error == 0 && (fvp->v_flag & VROOT)) {
                vput(fvp);      /* as if vop_old_lookup had failed */
                error = EBUSY;
        }
        if ((fcnp.cn_flags & CNP_PDIRUNLOCK) == 0) {
                fcnp.cn_flags |= CNP_PDIRUNLOCK;
                VOP_UNLOCK(fdvp, 0, td);
        }
        if (error) {
                vrele(fdvp);
                return (error);
        }
        VOP_UNLOCK(fvp, 0, td);

        /*
         * fdvp and fvp are now referenced and unlocked.
         *
         * Get a locked directory vnode for the target and lookup the target
         * in CREATE mode so it places the required information in the
         * directory inode.
         */
        tncp = ap->a_tncp;              /* locked namecache node */
        if (tncp->nc_flag & NCF_MOUNTPT) /* can't cross a mount point! */
                error = EPERM;
        if (tncp->nc_parent == NULL)
                error = EPERM;
        if ((tdvp = tncp->nc_parent->nc_vp) == NULL)
                error = EPERM;
        if (error) {
                vrele(fdvp);
                vrele(fvp);
                return (error);
        }
        if ((error = vget(tdvp, LK_EXCLUSIVE, td)) != 0) {
                printf("[diagnostic] vop_compat_resolve: EAGAIN on ncp %p %s\n",
                        tncp, tncp->nc_name);
                vrele(fdvp);
                vrele(fvp);
                return(EAGAIN);
        }

        /*
         * Setup the cnp for a traditional vop_old_lookup() call.  The lookup
         * caches all information required to create the entry in the
         * target directory inode.
         */
        bzero(&tcnp, sizeof(tcnp));
        tcnp.cn_nameiop = NAMEI_RENAME;
        tcnp.cn_flags = CNP_LOCKPARENT;
        tcnp.cn_nameptr = tncp->nc_name;
        tcnp.cn_namelen = tncp->nc_nlen;
        tcnp.cn_cred = ap->a_cred;
        tcnp.cn_td = td;

        tvp = NULL;
        error = vop_old_lookup(ap->a_head.a_ops, tdvp, &tvp, &tcnp);

        if (error == EJUSTRETURN) {
                /*
                 * Target does not exist.  tvp should be NULL.
                 */
                KKASSERT(tvp == NULL);
                KKASSERT((tcnp.cn_flags & CNP_PDIRUNLOCK) == 0);
                error = VOP_OLD_RENAME(fdvp, fvp, &fcnp, tdvp, tvp, &tcnp);
                if (error == 0) {
                        cache_rename(fncp, tncp);
                        cache_setvp(tncp, fvp);
                }
        } else if (error == 0) {
                /*
                 * Target exists.  VOP_OLD_RENAME should correctly delete the
                 * target.
                 */
                KKASSERT((tcnp.cn_flags & CNP_PDIRUNLOCK) == 0);
                error = VOP_OLD_RENAME(fdvp, fvp, &fcnp, tdvp, tvp, &tcnp);
                if (error == 0) {
                        cache_rename(fncp, tncp);
                        cache_setvp(tncp, fvp);
                }
        } else {
                vrele(fdvp);
                vrele(fvp);
                if (tcnp.cn_flags & CNP_PDIRUNLOCK)
                        vrele(tdvp);
                else
                        vput(tdvp);
        }
        return (error);
}

static int
vop_nolookup(ap)
        struct vop_old_lookup_args /* {
                struct vnode *a_dvp;
                struct vnode **a_vpp;
                struct componentname *a_cnp;
        } */ *ap;
{

        *ap->a_vpp = NULL;
        return (ENOTDIR);
}

/*
 *      vop_nostrategy:
 *
 *      Strategy routine for VFS devices that have none.
 *
 *      B_ERROR and B_INVAL must be cleared prior to calling any strategy
 *      routine.  Typically this is done for a B_READ strategy call.  Typically
 *      B_INVAL is assumed to already be clear prior to a write and should not
 *      be cleared manually unless you just made the buffer invalid.  B_ERROR
 *      should be cleared either way.
 */

static int
vop_nostrategy (struct vop_strategy_args *ap)
{
        printf("No strategy for buffer at %p\n", ap->a_bio->bio_buf);
        vprint("", ap->a_vp);
        vprint("", ap->a_bio->bio_buf->b_vp);
        ap->a_bio->bio_buf->b_flags |= B_ERROR;
        ap->a_bio->bio_buf->b_error = EOPNOTSUPP;
        biodone(ap->a_bio);
        return (EOPNOTSUPP);
}

int
vop_stdpathconf(ap)
        struct vop_pathconf_args /* {
        struct vnode *a_vp;
        int a_name;
        int *a_retval;
        } */ *ap;
{

        switch (ap->a_name) {
                case _PC_LINK_MAX:
                        *ap->a_retval = LINK_MAX;
                        return (0);
                case _PC_MAX_CANON:
                        *ap->a_retval = MAX_CANON;
                        return (0);
                case _PC_MAX_INPUT:
                        *ap->a_retval = MAX_INPUT;
                        return (0);
                case _PC_PIPE_BUF:
                        *ap->a_retval = PIPE_BUF;
                        return (0);
                case _PC_CHOWN_RESTRICTED:
                        *ap->a_retval = 1;
                        return (0);
                case _PC_VDISABLE:
                        *ap->a_retval = _POSIX_VDISABLE;
                        return (0);
                default:
                        return (EINVAL);
        }
        /* NOTREACHED */
}

/*
 * Standard lock.  The lock is recursive-capable only if the lock was
 * initialized with LK_CANRECURSE or that flag is passed in a_flags.
 */
int
vop_stdlock(ap)
        struct vop_lock_args /* {
                struct vnode *a_vp;
                int a_flags;
                struct proc *a_p;
        } */ *ap;
{               
        int error;

#ifndef DEBUG_LOCKS
        error = lockmgr(&ap->a_vp->v_lock, ap->a_flags, NULL, ap->a_td);
#else
        error = debuglockmgr(&ap->a_vp->v_lock, ap->a_flags,
                        NULL, ap->a_td,
                        "vop_stdlock", ap->a_vp->filename, ap->a_vp->line);
#endif
        return(error);
}

int
vop_stdunlock(ap)
        struct vop_unlock_args /* {
                struct vnode *a_vp;
                int a_flags;
                struct thread *a_td;
        } */ *ap;
{
        int error;

        error = lockmgr(&ap->a_vp->v_lock, ap->a_flags | LK_RELEASE,
                        NULL, ap->a_td);
        return(error);
}

int
vop_stdislocked(ap)
        struct vop_islocked_args /* {
                struct vnode *a_vp;
                struct thread *a_td;
        } */ *ap;
{
        return (lockstatus(&ap->a_vp->v_lock, ap->a_td));
}

/*
 * Return true for select/poll.
 */
int
vop_nopoll(ap)
        struct vop_poll_args /* {
                struct vnode *a_vp;
                int  a_events;
                struct ucred *a_cred;
                struct proc *a_p;
        } */ *ap;
{
        /*
         * Return true for read/write.  If the user asked for something
         * special, return POLLNVAL, so that clients have a way of
         * determining reliably whether or not the extended
         * functionality is present without hard-coding knowledge
         * of specific filesystem implementations.
         */
        if (ap->a_events & ~POLLSTANDARD)
                return (POLLNVAL);

        return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
}

/*
 * Implement poll for local filesystems that support it.
 */
int
vop_stdpoll(ap)
        struct vop_poll_args /* {
                struct vnode *a_vp;
                int  a_events;
                struct ucred *a_cred;
                struct thread *a_td;
        } */ *ap;
{
        if (ap->a_events & ~POLLSTANDARD)
                return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
        return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
}

int
vop_stdbwrite(ap)
        struct vop_bwrite_args *ap;
{
        return (bwrite(ap->a_bp));
}

int
vop_stdcreatevobject(ap)
        struct vop_createvobject_args /* {
                struct vnode *a_vp;
                struct proc *a_td;
        } */ *ap;
{
        struct vnode *vp = ap->a_vp;
        struct thread *td = ap->a_td;
        struct vattr vat;
        vm_object_t object;
        int error = 0;

        if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
                return (0);

retry:
        if ((object = vp->v_object) == NULL) {
                if (vp->v_type == VREG || vp->v_type == VDIR) {
                        if ((error = VOP_GETATTR(vp, &vat, td)) != 0)
                                goto retn;
                        object = vnode_pager_alloc(vp, vat.va_size, 0, 0);
                } else if (vp->v_rdev && dev_is_good(vp->v_rdev)) {
                        /*
                         * XXX v_rdev uses NULL/non-NULL instead of NODEV
                         *
                         * This simply allocates the biggest object possible
                         * for a disk vnode.  This should be fixed, but doesn't
                         * cause any problems (yet).
                         */
                        object = vnode_pager_alloc(vp, IDX_TO_OFF(INT_MAX), 0, 0);
                } else {
                        goto retn;
                }
                /*
                 * Dereference the reference we just created.  This assumes
                 * that the object is associated with the vp.
                 */
                object->ref_count--;
                vp->v_usecount--;
        } else {
                if (object->flags & OBJ_DEAD) {
                        VOP_UNLOCK(vp, 0, td);
                        tsleep(object, 0, "vodead", 0);
                        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
                        goto retry;
                }
        }

        KASSERT(vp->v_object != NULL, ("vfs_object_create: NULL object"));
        vp->v_flag |= VOBJBUF;

retn:
        return (error);
}

int
vop_stddestroyvobject(ap)
        struct vop_destroyvobject_args /* {
                struct vnode *vp;
        } */ *ap;
{
        struct vnode *vp = ap->a_vp;
        vm_object_t obj = vp->v_object;

        if (vp->v_object == NULL)
                return (0);

        if (obj->ref_count == 0) {
                /*
                 * vclean() may be called twice. The first time
                 * removes the primary reference to the object,
                 * the second time goes one further and is a
                 * special-case to terminate the object.
                 *
                 * don't double-terminate the object.
                 */
                if ((obj->flags & OBJ_DEAD) == 0)
                        vm_object_terminate(obj);
        } else {
                /*
                 * Woe to the process that tries to page now :-).
                 */
                vm_pager_deallocate(obj);
        }
        return (0);
}

/*
 * Return the underlying VM object.  This routine may be called with or
 * without the vnode interlock held.  If called without, the returned
 * object is not guarenteed to be valid.  The syncer typically gets the
 * object without holding the interlock in order to quickly test whether
 * it might be dirty before going heavy-weight.  vm_object's use zalloc
 * and thus stable-storage, so this is safe.
 */
int
vop_stdgetvobject(ap)
        struct vop_getvobject_args /* {
                struct vnode *vp;
                struct vm_object **objpp;
        } */ *ap;
{
        struct vnode *vp = ap->a_vp;
        struct vm_object **objpp = ap->a_objpp;

        if (objpp)
                *objpp = vp->v_object;
        return (vp->v_object ? 0 : EINVAL);
}

/* 
 * vfs default ops
 * used to fill the vfs fucntion table to get reasonable default return values.
 */
int 
vfs_stdmount(struct mount *mp, char *path, caddr_t data, struct thread *td)
{
        return (0);
}

int     
vfs_stdunmount(struct mount *mp, int mntflags, struct thread *td)
{
        return (0);
}

int     
vfs_stdroot(struct mount *mp, struct vnode **vpp)
{
        return (EOPNOTSUPP);
}

int     
vfs_stdstatfs(struct mount *mp, struct statfs *sbp, struct thread *td)
{
        return (EOPNOTSUPP);
}

int
vfs_stdvptofh(struct vnode *vp, struct fid *fhp)
{
        return (EOPNOTSUPP);
}

int     
vfs_stdstart(struct mount *mp, int flags, struct thread *td)
{
        return (0);
}

int     
vfs_stdquotactl(struct mount *mp, int cmds, uid_t uid,
        caddr_t arg, struct thread *td)
{
        return (EOPNOTSUPP);
}

int     
vfs_stdsync(struct mount *mp, int waitfor, struct thread *td)
{
        return (0);
}

int
vfs_stdnosync(struct mount *mp, int waitfor, struct thread *td)
{
        return (EOPNOTSUPP);
}

int     
vfs_stdvget(struct mount *mp, ino_t ino, struct vnode **vpp)
{
        return (EOPNOTSUPP);
}

int     
vfs_stdfhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
{
        return (EOPNOTSUPP);
}

int 
vfs_stdcheckexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
        struct ucred **credanonp)
{
        return (EOPNOTSUPP);
}

int
vfs_stdinit(struct vfsconf *vfsp)
{
        return (0);
}

int
vfs_stduninit(struct vfsconf *vfsp)
{
        return(0);
}

int
vfs_stdextattrctl(struct mount *mp, int cmd, const char *attrname,
        caddr_t arg, struct thread *td)
{
        return(EOPNOTSUPP);
}

/* end of vfs default ops */