[apple/xnu.git] / bsd / ufs / ufs / ufs_vnops.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_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 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.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1982, 1986, 1989, 1993, 1995
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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.
 *
 *      @(#)ufs_vnops.c 8.27 (Berkeley) 5/27/95
 */

#include <rev_endian_fs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/resourcevar.h>
#include <sys/kernel.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/conf.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/dirent.h>
#include <sys/fcntl.h>
#include <sys/ubc.h>
#include <sys/quota.h>

#include <kern/thread.h>
#include <sys/vm.h>

#include <miscfs/specfs/specdev.h>

#include <ufs/ufs/lockf.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/dir.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/ufs_extern.h>

#if REV_ENDIAN_FS
#include <ufs/ufs/ufs_byte_order.h>
#include <architecture/byte_order.h>
#endif /* REV_ENDIAN_FS */

static int ufs_chmod __P((struct vnode *, int, struct ucred *, struct proc *));
static int ufs_chown
        __P((struct vnode *, uid_t, gid_t, struct ucred *, struct proc *));

union _qcvt {
        int64_t qcvt;
        int32_t val[2];
};
#define SETHIGH(q, h) { \
        union _qcvt tmp; \
        tmp.qcvt = (q); \
        tmp.val[_QUAD_HIGHWORD] = (h); \
        (q) = tmp.qcvt; \
}
#define SETLOW(q, l) { \
        union _qcvt tmp; \
        tmp.qcvt = (q); \
        tmp.val[_QUAD_LOWWORD] = (l); \
        (q) = tmp.qcvt; \
}

/*
 * Create a regular file
 */
int
ufs_create(ap)
        struct vop_create_args /* {
                struct vnode *a_dvp;
                struct vnode **a_vpp;
                struct componentname *a_cnp;
                struct vattr *a_vap;
        } */ *ap;
{
        int error;

        if (error =
            ufs_makeinode(MAKEIMODE(ap->a_vap->va_type, ap->a_vap->va_mode),
            ap->a_dvp, ap->a_vpp, ap->a_cnp))
                return (error);
        return (0);
}

/*
 * Mknod vnode call
 */
/* ARGSUSED */
int
ufs_mknod(ap)
        struct vop_mknod_args /* {
                struct vnode *a_dvp;
                struct vnode **a_vpp;
                struct componentname *a_cnp;
                struct vattr *a_vap;
        } */ *ap;
{
        struct vattr *vap = ap->a_vap;
        struct vnode **vpp = ap->a_vpp;
        struct inode *ip;
        int error;

        if (error =
            ufs_makeinode(MAKEIMODE(vap->va_type, vap->va_mode),
            ap->a_dvp, vpp, ap->a_cnp))
                return (error);
        ip = VTOI(*vpp);
        ip->i_flag |= IN_ACCESS | IN_CHANGE | IN_UPDATE;
        if (vap->va_rdev != VNOVAL) {
                /*
                 * Want to be able to use this to make badblock
                 * inodes, so don't truncate the dev number.
                 */
                ip->i_rdev = vap->va_rdev;
        }
        /*
         * Remove inode so that it will be reloaded by VFS_VGET and
         * checked to see if it is an alias of an existing entry in
         * the inode cache.
         */
        vput(*vpp);
        (*vpp)->v_type = VNON;
        vgone(*vpp);
        *vpp = 0;
        return (0);
}

/*
 * Open called.
 *
 * Nothing to do.
 */
/* ARGSUSED */
int
ufs_open(ap)
        struct vop_open_args /* {
                struct vnode *a_vp;
                int  a_mode;
                struct ucred *a_cred;
                struct proc *a_p;
        } */ *ap;
{

        /*
         * Files marked append-only must be opened for appending.
         */
        if ((VTOI(ap->a_vp)->i_flags & APPEND) &&
            (ap->a_mode & (FWRITE | O_APPEND)) == FWRITE)
                return (EPERM);
        return (0);
}

/*
 * Close called.
 *
 * Update the times on the inode.
 */
/* ARGSUSED */
int
ufs_close(ap)
        struct vop_close_args /* {
                struct vnode *a_vp;
                int  a_fflag;
                struct ucred *a_cred;
                struct proc *a_p;
        } */ *ap;
{
        register struct vnode *vp = ap->a_vp;
        register struct inode *ip = VTOI(vp);

        simple_lock(&vp->v_interlock);
        if ((!UBCISVALID(vp) && vp->v_usecount > 1)
            || (UBCISVALID(vp) && ubc_isinuse(vp, 1)))
                ITIMES(ip, &time, &time);
        simple_unlock(&vp->v_interlock);

        if (!VOP_ISLOCKED(vp)) {
                vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, ap->a_p);

                cluster_push(vp);

                VOP_UNLOCK(vp, 0, ap->a_p);
        }
        return (0);
}

int
ufs_access(ap)
        struct vop_access_args /* {
                struct vnode *a_vp;
                int  a_mode;
                struct ucred *a_cred;
                struct proc *a_p;
        } */ *ap;
{
        struct vnode *vp = ap->a_vp;
        struct inode *ip = VTOI(vp);
        struct ucred *cred = ap->a_cred;
        mode_t mask, mode = ap->a_mode;
        register gid_t *gp;
        int i, error;

        /*
         * Disallow write attempts on read-only file systems;
         * unless the file is a socket, fifo, or a block or
         * character device resident on the file system.
         */
        if (mode & VWRITE) {
                switch (vp->v_type) {
                case VDIR:
                case VLNK:
                case VREG:
                        if (vp->v_mount->mnt_flag & MNT_RDONLY)
                                return (EROFS);
#if QUOTA
                        if (error = getinoquota(ip))
                                return (error);
#endif
                        break;
                }
        }

        /* If immutable bit set, nobody gets to write it. */
        if ((mode & VWRITE) && (ip->i_flags & IMMUTABLE))
                return (EPERM);

        /* Otherwise, user id 0 always gets access. */
        if (cred->cr_uid == 0)
                return (0);

        mask = 0;

        /* Otherwise, check the owner. */
        if (cred->cr_uid == ip->i_uid) {
                if (mode & VEXEC)
                        mask |= S_IXUSR;
                if (mode & VREAD)
                        mask |= S_IRUSR;
                if (mode & VWRITE)
                        mask |= S_IWUSR;
                return ((ip->i_mode & mask) == mask ? 0 : EACCES);
        }

        /* Otherwise, check the groups. */
        for (i = 0, gp = cred->cr_groups; i < cred->cr_ngroups; i++, gp++)
                if (ip->i_gid == *gp) {
                        if (mode & VEXEC)
                                mask |= S_IXGRP;
                        if (mode & VREAD)
                                mask |= S_IRGRP;
                        if (mode & VWRITE)
                                mask |= S_IWGRP;
                        return ((ip->i_mode & mask) == mask ? 0 : EACCES);
                }

        /* Otherwise, check everyone else. */
        if (mode & VEXEC)
                mask |= S_IXOTH;
        if (mode & VREAD)
                mask |= S_IROTH;
        if (mode & VWRITE)
                mask |= S_IWOTH;
        return ((ip->i_mode & mask) == mask ? 0 : EACCES);
}

/* ARGSUSED */
int
ufs_getattr(ap)
        struct vop_getattr_args /* {
                struct vnode *a_vp;
                struct vattr *a_vap;
                struct ucred *a_cred;
                struct proc *a_p;
        } */ *ap;
{
        register struct vnode *vp = ap->a_vp;
        register struct inode *ip = VTOI(vp);
        register struct vattr *vap = ap->a_vap;
        int devBlockSize=0;

        ITIMES(ip, &time, &time);
        /*
         * Copy from inode table
         */
        vap->va_fsid = ip->i_dev;
        vap->va_fileid = ip->i_number;
        vap->va_mode = ip->i_mode & ~IFMT;
        vap->va_nlink = ip->i_nlink;
        vap->va_uid = ip->i_uid;
        vap->va_gid = ip->i_gid;
        vap->va_rdev = (dev_t)ip->i_rdev;
        vap->va_size = ip->i_din.di_size;
        vap->va_atime.tv_sec = ip->i_atime;
        vap->va_atime.tv_nsec = ip->i_atimensec;
        vap->va_mtime.tv_sec = ip->i_mtime;
        vap->va_mtime.tv_nsec = ip->i_mtimensec;
        vap->va_ctime.tv_sec = ip->i_ctime;
        vap->va_ctime.tv_nsec = ip->i_ctimensec;
        vap->va_flags = ip->i_flags;
        vap->va_gen = ip->i_gen;
        /* this doesn't belong here */
        if (vp->v_type == VBLK)
                vap->va_blocksize = BLKDEV_IOSIZE;
        else if (vp->v_type == VCHR)
                vap->va_blocksize = MAXPHYSIO;
        else
                vap->va_blocksize = vp->v_mount->mnt_stat.f_iosize;
        VOP_DEVBLOCKSIZE(ip->i_devvp, &devBlockSize);
        vap->va_bytes = dbtob((u_quad_t)ip->i_blocks, devBlockSize);
        vap->va_type = vp->v_type;
        vap->va_filerev = ip->i_modrev;
        return (0);
}

/*
 * Set attribute vnode op. called from several syscalls
 */
int
ufs_setattr(ap)
        struct vop_setattr_args /* {
                struct vnode *a_vp;
                struct vattr *a_vap;
                struct ucred *a_cred;
                struct proc *a_p;
        } */ *ap;
{
        struct vattr *vap = ap->a_vap;
        struct vnode *vp = ap->a_vp;
        struct inode *ip = VTOI(vp);
        struct ucred *cred = ap->a_cred;
        struct proc *p = ap->a_p;
        struct timeval atimeval, mtimeval;
        int error;

        /*
         * Check for unsettable attributes.
         */
        if ((vap->va_type != VNON) || (vap->va_nlink != VNOVAL) ||
            (vap->va_fsid != VNOVAL) || (vap->va_fileid != VNOVAL) ||
            (vap->va_blocksize != VNOVAL) || (vap->va_rdev != VNOVAL) ||
            ((int)vap->va_bytes != VNOVAL) || (vap->va_gen != VNOVAL)) {
                return (EINVAL);
        }
        if (vap->va_flags != VNOVAL) {
                if (vp->v_mount->mnt_flag & MNT_RDONLY)
                        return (EROFS);
                if (cred->cr_uid != ip->i_uid &&
                    (error = suser(cred, &p->p_acflag)))
                        return (error);
                if (cred->cr_uid == 0) {
                        if ((ip->i_flags & (SF_IMMUTABLE | SF_APPEND)) &&
                            securelevel > 0)
                                return (EPERM);
                        ip->i_flags = vap->va_flags;
                } else {
                        if (ip->i_flags & (SF_IMMUTABLE | SF_APPEND) ||
                            (vap->va_flags & UF_SETTABLE) != vap->va_flags)
                                return (EPERM);
                        ip->i_flags &= SF_SETTABLE;
                        ip->i_flags |= (vap->va_flags & UF_SETTABLE);
                }
                ip->i_flag |= IN_CHANGE;
                if (vap->va_flags & (IMMUTABLE | APPEND))
                        return (0);
        }
        if (ip->i_flags & (IMMUTABLE | APPEND))
                return (EPERM);
        /*
         * Go through the fields and update iff not VNOVAL.
         */
        if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
                if (vp->v_mount->mnt_flag & MNT_RDONLY)
                        return (EROFS);
                if (error = ufs_chown(vp, vap->va_uid, vap->va_gid, cred, p))
                        return (error);
        }
        if (vap->va_size != VNOVAL) {
                /*
                 * Disallow write attempts on read-only file systems;
                 * unless the file is a socket, fifo, or a block or
                 * character device resident on the file system.
                 */
                switch (vp->v_type) {
                case VDIR:
                        return (EISDIR);
                case VLNK:
                case VREG:
                        if (vp->v_mount->mnt_flag & MNT_RDONLY)
                                return (EROFS);
                        break;
                }
                if (error = VOP_TRUNCATE(vp, vap->va_size, 0, cred, p))
                        return (error);
        }
        ip = VTOI(vp);
        if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
                if (vp->v_mount->mnt_flag & MNT_RDONLY)
                        return (EROFS);
                if (cred->cr_uid != ip->i_uid &&
                    (error = suser(cred, &p->p_acflag)) &&
                    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 || 
                    (error = VOP_ACCESS(vp, VWRITE, cred, p))))
                        return (error);
                if (vap->va_atime.tv_sec != VNOVAL)
                        ip->i_flag |= IN_ACCESS;
                if (vap->va_mtime.tv_sec != VNOVAL)
                        ip->i_flag |= IN_CHANGE | IN_UPDATE;
                atimeval.tv_sec = vap->va_atime.tv_sec;
                atimeval.tv_usec = vap->va_atime.tv_nsec / 1000;
                mtimeval.tv_sec = vap->va_mtime.tv_sec;
                mtimeval.tv_usec = vap->va_mtime.tv_nsec / 1000;
                if (error = VOP_UPDATE(vp, &atimeval, &mtimeval, 1))
                        return (error);
        }
        error = 0;
        if (vap->va_mode != (mode_t)VNOVAL) {
                if (vp->v_mount->mnt_flag & MNT_RDONLY)
                        return (EROFS);
                error = ufs_chmod(vp, (int)vap->va_mode, cred, p);
        }
        return (error);
}

/*
 * Change the mode on a file.
 * Inode must be locked before calling.
 */
static int
ufs_chmod(vp, mode, cred, p)
        register struct vnode *vp;
        register int mode;
        register struct ucred *cred;
        struct proc *p;
{
        register struct inode *ip = VTOI(vp);
        int error;

        if (cred->cr_uid != ip->i_uid &&
            (error = suser(cred, &p->p_acflag)))
                return (error);
        if (cred->cr_uid) {
                if (vp->v_type != VDIR && (mode & S_ISTXT))
                        return (EFTYPE);
                if (!groupmember(ip->i_gid, cred) && (mode & ISGID))
                        return (EPERM);
        }
        ip->i_mode &= ~ALLPERMS;
        ip->i_mode |= (mode & ALLPERMS);
        ip->i_flag |= IN_CHANGE;
        return (0);
}

/*
 * Perform chown operation on inode ip;
 * inode must be locked prior to call.
 */
static int
ufs_chown(vp, uid, gid, cred, p)
        register struct vnode *vp;
        uid_t uid;
        gid_t gid;
        struct ucred *cred;
        struct proc *p;
{
        register struct inode *ip = VTOI(vp);
        uid_t ouid;
        gid_t ogid;
        int error = 0;
#if QUOTA
        register int i;
        int64_t change;   /* in bytes */
        int devBlockSize=0;
#endif /* QUOTA */

        if (uid == (uid_t)VNOVAL)
                uid = ip->i_uid;
        if (gid == (gid_t)VNOVAL)
                gid = ip->i_gid;
        /*
         * If we don't own the file, are trying to change the owner
         * of the file, or are not a member of the target group,
         * the caller must be superuser or the call fails.
         */
        if ((cred->cr_uid != ip->i_uid || uid != ip->i_uid ||
            (gid != ip->i_gid && !groupmember((gid_t)gid, cred))) &&
            (error = suser(cred, &p->p_acflag)))
                return (error);
        ogid = ip->i_gid;
        ouid = ip->i_uid;
#if QUOTA
        if (error = getinoquota(ip))
                return (error);
        if (ouid == uid) {
                dqrele(vp, ip->i_dquot[USRQUOTA]);
                ip->i_dquot[USRQUOTA] = NODQUOT;
        }
        if (ogid == gid) {
                dqrele(vp, ip->i_dquot[GRPQUOTA]);
                ip->i_dquot[GRPQUOTA] = NODQUOT;
        }
        VOP_DEVBLOCKSIZE(ip->i_devvp, &devBlockSize);
        change = dbtob((int64_t)ip->i_blocks, devBlockSize);
        (void) chkdq(ip, -change, cred, CHOWN);
        (void) chkiq(ip, -1, cred, CHOWN);
        for (i = 0; i < MAXQUOTAS; i++) {
                dqrele(vp, ip->i_dquot[i]);
                ip->i_dquot[i] = NODQUOT;
        }
#endif
        ip->i_gid = gid;
        ip->i_uid = uid;
#if QUOTA
        if ((error = getinoquota(ip)) == 0) {
                if (ouid == uid) {
                        dqrele(vp, ip->i_dquot[USRQUOTA]);
                        ip->i_dquot[USRQUOTA] = NODQUOT;
                }
                if (ogid == gid) {
                        dqrele(vp, ip->i_dquot[GRPQUOTA]);
                        ip->i_dquot[GRPQUOTA] = NODQUOT;
                }
                if ((error = chkdq(ip, change, cred, CHOWN)) == 0) {
                        if ((error = chkiq(ip, 1, cred, CHOWN)) == 0)
                                goto good;
                        else
                                (void) chkdq(ip, -change, cred, CHOWN|FORCE);
                }
                for (i = 0; i < MAXQUOTAS; i++) {
                        dqrele(vp, ip->i_dquot[i]);
                        ip->i_dquot[i] = NODQUOT;
                }
        }
        ip->i_gid = ogid;
        ip->i_uid = ouid;
        if (getinoquota(ip) == 0) {
                if (ouid == uid) {
                        dqrele(vp, ip->i_dquot[USRQUOTA]);
                        ip->i_dquot[USRQUOTA] = NODQUOT;
                }
                if (ogid == gid) {
                        dqrele(vp, ip->i_dquot[GRPQUOTA]);
                        ip->i_dquot[GRPQUOTA] = NODQUOT;
                }
                (void) chkdq(ip, change, cred, FORCE|CHOWN);
                (void) chkiq(ip, 1, cred, FORCE|CHOWN);
                (void) getinoquota(ip);
        }
        return (error);
good:
        if (getinoquota(ip))
                panic("chown: lost quota");
#endif /* QUOTA */
        if (ouid != uid || ogid != gid)
                ip->i_flag |= IN_CHANGE;
        if (ouid != uid && cred->cr_uid != 0)
                ip->i_mode &= ~ISUID;
        if (ogid != gid && cred->cr_uid != 0)
                ip->i_mode &= ~ISGID;
        return (0);
}

/* ARGSUSED */
int
ufs_ioctl(ap)
        struct vop_ioctl_args /* {
                struct vnode *a_vp;
                int  a_command;
                caddr_t  a_data;
                int  a_fflag;
                struct ucred *a_cred;
                struct proc *a_p;
        } */ *ap;
{

        switch (ap->a_command) {
        
        case 1:
        {       register struct inode *ip;
                register struct vnode *vp;
                register struct fs *fs;
                register struct radvisory *ra;
                int devBlockSize = 0;
                int error;

                vp = ap->a_vp;

                VOP_LEASE(vp, ap->a_p, ap->a_cred, LEASE_READ);
                vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, ap->a_p);

                ra = (struct radvisory *)(ap->a_data);
                ip = VTOI(vp);
                fs = ip->i_fs;

                if ((u_int64_t)ra->ra_offset >= ip->i_size) {
                        VOP_UNLOCK(vp, 0, ap->a_p);
                        return (EFBIG);
                }
                VOP_DEVBLOCKSIZE(ip->i_devvp, &devBlockSize);

                error = advisory_read(vp, ip->i_size, ra->ra_offset, ra->ra_count, devBlockSize);
                VOP_UNLOCK(vp, 0, ap->a_p);
                return (error);
        }
        default:
                return (ENOTTY);
        }
}

/* ARGSUSED */
int
ufs_select(ap)
        struct vop_select_args /* {
                struct vnode *a_vp;
                int  a_which;
                int  a_fflags;
                struct ucred *a_cred;
                void *a_wql;
                struct proc *a_p;
        } */ *ap;
{

        /*
         * We should really check to see if I/O is possible.
         */
        return (1);
}

/*
 * Mmap a file
 *
 * NB Currently unsupported.
 */
/* ARGSUSED */
int
ufs_mmap(ap)
        struct vop_mmap_args /* {
                struct vnode *a_vp;
                int  a_fflags;
                struct ucred *a_cred;
                struct proc *a_p;
        } */ *ap;
{

        return (EINVAL);
}

/*
 * Seek on a file
 *
 * Nothing to do, so just return.
 */
/* ARGSUSED */
int
ufs_seek(ap)
        struct vop_seek_args /* {
                struct vnode *a_vp;
                off_t  a_oldoff;
                off_t  a_newoff;
                struct ucred *a_cred;
        } */ *ap;
{

        return (0);
}

int
ufs_remove(ap)
        struct vop_remove_args /* {
                struct vnode *a_dvp;
                struct vnode *a_vp;
                struct componentname *a_cnp;
        } */ *ap;
{
        struct inode *ip;
        struct vnode *vp = ap->a_vp;
        struct vnode *dvp = ap->a_dvp;
        int error;

        ip = VTOI(vp);
        if ((ip->i_flags & (IMMUTABLE | APPEND)) ||
            (VTOI(dvp)->i_flags & APPEND)) {
                error = EPERM;
                goto out;
        }

        if (ap->a_cnp->cn_flags & NODELETEBUSY) {
                /* Caller requested Carbon delete semantics */
                if ((!UBCISVALID(vp) && vp->v_usecount > 1)
                    || (UBCISVALID(vp) && ubc_isinuse(vp, 1))) {
                        error = EBUSY;
                        goto out;
                }
        }

        if ((error = ufs_dirremove(dvp, ap->a_cnp)) == 0) {
                ip->i_nlink--;
                ip->i_flag |= IN_CHANGE;
        }

        if (dvp != vp)
                VOP_UNLOCK(vp, 0, ap->a_cnp->cn_proc);

        (void) ubc_uncache(vp); 

        vrele(vp);
        vput(dvp);

        return (error);

out:
        if (dvp == vp)
                vrele(vp);
        else
                vput(vp);
        vput(dvp);
        return (error);
}

/*
 * link vnode call
 */
int
ufs_link(ap)
        struct vop_link_args /* {
                struct vnode *a_vp;
                struct vnode *a_tdvp;
                struct componentname *a_cnp;
        } */ *ap;
{
        struct vnode *vp = ap->a_vp;
        struct vnode *tdvp = ap->a_tdvp;
        struct componentname *cnp = ap->a_cnp;
        struct proc *p = cnp->cn_proc;
        struct inode *ip;
        struct timeval tv;
        int error;

#if DIAGNOSTIC
        if ((cnp->cn_flags & HASBUF) == 0)
                panic("ufs_link: no name");
#endif
        if (tdvp->v_mount != vp->v_mount) {
                VOP_ABORTOP(tdvp, cnp);
                error = EXDEV;
                goto out2;
        }
        if (tdvp != vp && (error = vn_lock(vp, LK_EXCLUSIVE, p))) {
                VOP_ABORTOP(tdvp, cnp);
                goto out2;
        }
        ip = VTOI(vp);
        if ((nlink_t)ip->i_nlink >= LINK_MAX) {
                VOP_ABORTOP(tdvp, cnp);
                error = EMLINK;
                goto out1;
        }
        if (ip->i_flags & (IMMUTABLE | APPEND)) {
                VOP_ABORTOP(tdvp, cnp);
                error = EPERM;
                goto out1;
        }
        ip->i_nlink++;
        ip->i_flag |= IN_CHANGE;
        tv = time;
        error = VOP_UPDATE(vp, &tv, &tv, 1);
        if (!error)
                error = ufs_direnter(ip, tdvp, cnp);
        if (error) {
                ip->i_nlink--;
                ip->i_flag |= IN_CHANGE;
        }
        FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
out1:
        if (tdvp != vp)
                VOP_UNLOCK(vp, 0, p);
out2:
        vput(tdvp);
        return (error);
}

/*
 * whiteout vnode call
 */
int
ufs_whiteout(ap)
        struct vop_whiteout_args /* {
                struct vnode *a_dvp;
                struct componentname *a_cnp;
                int a_flags;
        } */ *ap;
{
        struct vnode *dvp = ap->a_dvp;
        struct componentname *cnp = ap->a_cnp;
        struct direct newdir;
        int error;

        switch (ap->a_flags) {
        case LOOKUP:
                /* 4.4 format directories support whiteout operations */
                if (dvp->v_mount->mnt_maxsymlinklen > 0)
                        return (0);
                return (EOPNOTSUPP);

        case CREATE:
                /* create a new directory whiteout */
#if DIAGNOSTIC
                if ((cnp->cn_flags & SAVENAME) == 0)
                        panic("ufs_whiteout: missing name");
                if (dvp->v_mount->mnt_maxsymlinklen <= 0)
                        panic("ufs_whiteout: old format filesystem");
#endif

                newdir.d_ino = WINO;
                newdir.d_namlen = cnp->cn_namelen;
                bcopy(cnp->cn_nameptr, newdir.d_name, (unsigned)cnp->cn_namelen + 1);
                newdir.d_type = DT_WHT;
                error = ufs_direnter2(dvp, &newdir, cnp->cn_cred, cnp->cn_proc);
                break;

        case DELETE:
                /* remove an existing directory whiteout */
#if DIAGNOSTIC
                if (dvp->v_mount->mnt_maxsymlinklen <= 0)
                        panic("ufs_whiteout: old format filesystem");
#endif

                cnp->cn_flags &= ~DOWHITEOUT;
                error = ufs_dirremove(dvp, cnp);
                break;
        }
        if (cnp->cn_flags & HASBUF) {
                FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
                cnp->cn_flags &= ~HASBUF;
        }
        return (error);
}


/*
 * Rename system call.
 *      rename("foo", "bar");
 * is essentially
 *      unlink("bar");
 *      link("foo", "bar");
 *      unlink("foo");
 * but ``atomically''.  Can't do full commit without saving state in the
 * inode on disk which isn't feasible at this time.  Best we can do is
 * always guarantee the target exists.
 *
 * Basic algorithm is:
 *
 * 1) Bump link count on source while we're linking it to the
 *    target.  This also ensure the inode won't be deleted out
 *    from underneath us while we work (it may be truncated by
 *    a concurrent `trunc' or `open' for creation).
 * 2) Link source to destination.  If destination already exists,
 *    delete it first.
 * 3) Unlink source reference to inode if still around. If a
 *    directory was moved and the parent of the destination
 *    is different from the source, patch the ".." entry in the
 *    directory.
 */
int
ufs_rename(ap)
        struct vop_rename_args  /* {
                struct vnode *a_fdvp;
                struct vnode *a_fvp;
                struct componentname *a_fcnp;
                struct vnode *a_tdvp;
                struct vnode *a_tvp;
                struct componentname *a_tcnp;
        } */ *ap;
{
        struct vnode *tvp = ap->a_tvp;
        register struct vnode *tdvp = ap->a_tdvp;
        struct vnode *fvp = ap->a_fvp;
        struct vnode *fdvp = ap->a_fdvp;
        struct componentname *tcnp = ap->a_tcnp;
        struct componentname *fcnp = ap->a_fcnp;
        struct proc *p = fcnp->cn_proc;
        struct inode *ip, *xp, *dp;
        struct dirtemplate dirbuf;
        struct timeval tv;
        int doingdirectory = 0, oldparent = 0, newparent = 0;
        int error = 0;
        u_char namlen;

#if DIAGNOSTIC
        if ((tcnp->cn_flags & HASBUF) == 0 ||
            (fcnp->cn_flags & HASBUF) == 0)
                panic("ufs_rename: no name");
#endif
        /*
         * Check for cross-device rename.
         */
        if ((fvp->v_mount != tdvp->v_mount) ||
            (tvp && (fvp->v_mount != tvp->v_mount))) {
                error = EXDEV;
abortit:
                VOP_ABORTOP(tdvp, tcnp); /* XXX, why not in NFS? */
                if (tdvp == tvp)
                        vrele(tdvp);
                else
                        vput(tdvp);
                if (tvp)
                        vput(tvp);
                VOP_ABORTOP(fdvp, fcnp); /* XXX, why not in NFS? */
                vrele(fdvp);
                vrele(fvp);
                return (error);
        }

        /*
         * Check if just deleting a link name.
         */
        if (tvp && ((VTOI(tvp)->i_flags & (IMMUTABLE | APPEND)) ||
            (VTOI(tdvp)->i_flags & APPEND))) {
                error = EPERM;
                goto abortit;
        }
        if (fvp == tvp) {
                if (fvp->v_type == VDIR) {
                        error = EINVAL;
                        goto abortit;
                }

                /* Release destination completely. */
                VOP_ABORTOP(tdvp, tcnp);
                vput(tdvp);
                vput(tvp);

                /* Delete source. */
                vrele(fdvp);
                vrele(fvp);
                fcnp->cn_flags &= ~MODMASK;
                fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
                if ((fcnp->cn_flags & SAVESTART) == 0)
                        panic("ufs_rename: lost from startdir");
                fcnp->cn_nameiop = DELETE;
                (void) relookup(fdvp, &fvp, fcnp);
                return (VOP_REMOVE(fdvp, fvp, fcnp));
        }
        if (error = vn_lock(fvp, LK_EXCLUSIVE, p))
                goto abortit;
        dp = VTOI(fdvp);
        ip = VTOI(fvp);
        if ((ip->i_flags & (IMMUTABLE | APPEND)) || (dp->i_flags & APPEND)) {
                VOP_UNLOCK(fvp, 0, p);
                error = EPERM;
                goto abortit;
        }
        if ((ip->i_mode & IFMT) == IFDIR) {
                /*
                 * Avoid ".", "..", and aliases of "." for obvious reasons.
                 */
                if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
                    dp == ip || (fcnp->cn_flags&ISDOTDOT) ||
                    (ip->i_flag & IN_RENAME)) {
                        VOP_UNLOCK(fvp, 0, p);
                        error = EINVAL;
                        goto abortit;
                }
                ip->i_flag |= IN_RENAME;
                oldparent = dp->i_number;
                doingdirectory++;
        }
        vrele(fdvp);

        /*
         * When the target exists, both the directory
         * and target vnodes are returned locked.
         */
        dp = VTOI(tdvp);
        xp = NULL;
        if (tvp)
                xp = VTOI(tvp);

        /*
         * 1) Bump link count while we're moving stuff
         *    around.  If we crash somewhere before
         *    completing our work, the link count
         *    may be wrong, but correctable.
         */
        ip->i_nlink++;
        ip->i_flag |= IN_CHANGE;
        tv = time;
        if (error = VOP_UPDATE(fvp, &tv, &tv, 1)) {
                VOP_UNLOCK(fvp, 0, p);
                goto bad;
        }

        /*
         * If ".." must be changed (ie the directory gets a new
         * parent) then the source directory must not be in the
         * directory heirarchy above the target, as this would
         * orphan everything below the source directory. Also
         * the user must have write permission in the source so
         * as to be able to change "..". We must repeat the call 
         * to namei, as the parent directory is unlocked by the
         * call to checkpath().
         */
        error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_proc);
        VOP_UNLOCK(fvp, 0, p);
        if (oldparent != dp->i_number)
                newparent = dp->i_number;
        if (doingdirectory && newparent) {
                if (error)      /* write access check above */
                        goto bad;
                if (xp != NULL)
                        vput(tvp);
                if (error = ufs_checkpath(ip, dp, tcnp->cn_cred))
                        goto out;
                if ((tcnp->cn_flags & SAVESTART) == 0)
                        panic("ufs_rename: lost to startdir");
                if (error = relookup(tdvp, &tvp, tcnp))
                        goto out;
                dp = VTOI(tdvp);
                xp = NULL;
                if (tvp)
                        xp = VTOI(tvp);
        }
        /*
         * 2) If target doesn't exist, link the target
         *    to the source and unlink the source. 
         *    Otherwise, rewrite the target directory
         *    entry to reference the source inode and
         *    expunge the original entry's existence.
         */
        if (xp == NULL) {
                if (dp->i_dev != ip->i_dev)
                        panic("rename: EXDEV");
                /*
                 * Account for ".." in new directory.
                 * When source and destination have the same
                 * parent we don't fool with the link count.
                 */
                if (doingdirectory && newparent) {
                        if ((nlink_t)dp->i_nlink >= LINK_MAX) {
                                error = EMLINK;
                                goto bad;
                        }
                        dp->i_nlink++;
                        dp->i_flag |= IN_CHANGE;
                        if (error = VOP_UPDATE(tdvp, &tv, &tv, 1))
                                goto bad;
                }
                if (error = ufs_direnter(ip, tdvp, tcnp)) {
                        if (doingdirectory && newparent) {
                                dp->i_nlink--;
                                dp->i_flag |= IN_CHANGE;
                                (void)VOP_UPDATE(tdvp, &tv, &tv, 1);
                        }
                        goto bad;
                }
                vput(tdvp);
        } else {
                if (xp->i_dev != dp->i_dev || xp->i_dev != ip->i_dev)
                        panic("rename: EXDEV");
                /*
                 * Short circuit rename(foo, foo).
                 */
                if (xp->i_number == ip->i_number)
                        panic("rename: same file");
                /*
                 * If the parent directory is "sticky", then the user must
                 * own the parent directory, or the destination of the rename,
                 * otherwise the destination may not be changed (except by
                 * root). This implements append-only directories.
                 */
                if ((dp->i_mode & S_ISTXT) && tcnp->cn_cred->cr_uid != 0 &&
                    tcnp->cn_cred->cr_uid != dp->i_uid &&
                    xp->i_uid != tcnp->cn_cred->cr_uid) {
                        error = EPERM;
                        goto bad;
                }
                /*
                 * Target must be empty if a directory and have no links
                 * to it. Also, ensure source and target are compatible
                 * (both directories, or both not directories).
                 */
                if ((xp->i_mode&IFMT) == IFDIR) {
                        if (!ufs_dirempty(xp, dp->i_number, tcnp->cn_cred) || 
                            xp->i_nlink > 2) {
                                error = ENOTEMPTY;
                                goto bad;
                        }
                        if (!doingdirectory) {
                                error = ENOTDIR;
                                goto bad;
                        }
                        cache_purge(tdvp);
                } else if (doingdirectory) {
                        error = EISDIR;
                        goto bad;
                }
                if (error = ufs_dirrewrite(dp, ip, tcnp))
                        goto bad;
                /*
                 * If the target directory is in the same
                 * directory as the source directory,
                 * decrement the link count on the parent
                 * of the target directory.
                 */
                 if (doingdirectory && !newparent) {
                        dp->i_nlink--;
                        dp->i_flag |= IN_CHANGE;
                }
                vput(tdvp);
                /*
                 * Adjust the link count of the target to
                 * reflect the dirrewrite above.  If this is
                 * a directory it is empty and there are
                 * no links to it, so we can squash the inode and
                 * any space associated with it.  We disallowed
                 * renaming over top of a directory with links to
                 * it above, as the remaining link would point to
                 * a directory without "." or ".." entries.
                 */
                xp->i_nlink--;
                if (doingdirectory) {
                        if (--xp->i_nlink != 0)
                                panic("rename: linked directory");
                        error = VOP_TRUNCATE(tvp, (off_t)0, IO_SYNC,
                            tcnp->cn_cred, tcnp->cn_proc);
                }
                xp->i_flag |= IN_CHANGE;
                vput(tvp);
                xp = NULL;
        }

        /*
         * 3) Unlink the source.
         */
        fcnp->cn_flags &= ~MODMASK;
        fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
        if ((fcnp->cn_flags & SAVESTART) == 0)
                panic("ufs_rename: lost from startdir");
        (void) relookup(fdvp, &fvp, fcnp);
        if (fvp != NULL) {
                xp = VTOI(fvp);
                dp = VTOI(fdvp);
        } else {
                /*
                 * From name has disappeared.
                 */
                if (doingdirectory)
                        panic("rename: lost dir entry");
                vrele(ap->a_fvp);
                return (0);
        }
        /*
         * Ensure that the directory entry still exists and has not
         * changed while the new name has been entered. If the source is
         * a file then the entry may have been unlinked or renamed. In
         * either case there is no further work to be done. If the source
         * is a directory then it cannot have been rmdir'ed; its link
         * count of three would cause a rmdir to fail with ENOTEMPTY.
         * The IRENAME flag ensures that it cannot be moved by another
         * rename.
         */
        if (xp != ip) {
                if (doingdirectory)
                        panic("rename: lost dir entry");
        } else {
                /*
                 * If the source is a directory with a
                 * new parent, the link count of the old
                 * parent directory must be decremented
                 * and ".." set to point to the new parent.
                 */
                if (doingdirectory && newparent) {
                        dp->i_nlink--;
                        dp->i_flag |= IN_CHANGE;
                        error = vn_rdwr(UIO_READ, fvp, (caddr_t)&dirbuf,
                                sizeof (struct dirtemplate), (off_t)0,
                                UIO_SYSSPACE, IO_NODELOCKED, 
                                tcnp->cn_cred, (int *)0, (struct proc *)0);
                        if (error == 0) {
#                               if (BYTE_ORDER == LITTLE_ENDIAN)
                                        if (fvp->v_mount->mnt_maxsymlinklen <= 0)
                                                namlen = dirbuf.dotdot_type;
                                        else
                                                namlen = dirbuf.dotdot_namlen;
#                               else
                                        namlen = dirbuf.dotdot_namlen;
#                               endif
                                if (namlen != 2 ||
                                    dirbuf.dotdot_name[0] != '.' ||
                                    dirbuf.dotdot_name[1] != '.') {
                                        ufs_dirbad(xp, (doff_t)12,
                                            "rename: mangled dir");
                                } else {
                                        dirbuf.dotdot_ino = newparent;
                                        (void) vn_rdwr(UIO_WRITE, fvp,
                                            (caddr_t)&dirbuf,
                                            sizeof (struct dirtemplate),
                                            (off_t)0, UIO_SYSSPACE,
                                            IO_NODELOCKED|IO_SYNC,
                                            tcnp->cn_cred, (int *)0,
                                            (struct proc *)0);
                                        cache_purge(fdvp);
                                }
                        }
                }
                error = ufs_dirremove(fdvp, fcnp);
                if (!error) {
                        xp->i_nlink--;
                        xp->i_flag |= IN_CHANGE;
                }
                xp->i_flag &= ~IN_RENAME;
        }
        if (dp)
                vput(fdvp);
        if (xp)
                vput(fvp);
        vrele(ap->a_fvp);
        return (error);

bad:
        if (xp)
                vput(ITOV(xp));
        vput(ITOV(dp));
out:
        if (doingdirectory)
                ip->i_flag &= ~IN_RENAME;
        if (vn_lock(fvp, LK_EXCLUSIVE, p) == 0) {
                ip->i_nlink--;
                ip->i_flag |= IN_CHANGE;
                vput(fvp);
        } else
                vrele(fvp);
        return (error);
}

/*
 * A virgin directory (no blushing please).
 */
static struct dirtemplate mastertemplate = {
        0, 12, DT_DIR, 1, ".",
        0, DIRBLKSIZ - 12, DT_DIR, 2, ".."
};
static struct odirtemplate omastertemplate = {
        0, 12, 1, ".",
        0, DIRBLKSIZ - 12, 2, ".."
};

/*
 * Mkdir system call
 */
int
ufs_mkdir(ap)
        struct vop_mkdir_args /* {
                struct vnode *a_dvp;
                struct vnode **a_vpp;
                struct componentname *a_cnp;
                struct vattr *a_vap;
        } */ *ap;
{
        register struct vnode *dvp = ap->a_dvp;
        register struct vattr *vap = ap->a_vap;
        register struct componentname *cnp = ap->a_cnp;
        register struct inode *ip, *dp;
        struct vnode *tvp;
        struct dirtemplate dirtemplate, *dtp;
        struct timeval tv;
        int error, dmode;

#if DIAGNOSTIC
        if ((cnp->cn_flags & HASBUF) == 0)
                panic("ufs_mkdir: no name");
#endif
        dp = VTOI(dvp);
        if ((nlink_t)dp->i_nlink >= LINK_MAX) {
                error = EMLINK;
                goto out;
        }
        dmode = vap->va_mode & 0777;
        dmode |= IFDIR;
        /*
         * Must simulate part of ufs_makeinode here to acquire the inode,
         * but not have it entered in the parent directory. The entry is
         * made later after writing "." and ".." entries.
         */
        if (error = VOP_VALLOC(dvp, dmode, cnp->cn_cred, &tvp))
                goto out;
        ip = VTOI(tvp);
        ip->i_uid = cnp->cn_cred->cr_uid;
        ip->i_gid = dp->i_gid;
#if QUOTA
        if ((error = getinoquota(ip)) ||
            (error = chkiq(ip, 1, cnp->cn_cred, 0))) {
                _FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
                VOP_VFREE(tvp, ip->i_number, dmode);
                vput(tvp);
                vput(dvp);
                return (error);
        }
#endif
        ip->i_flag |= IN_ACCESS | IN_CHANGE | IN_UPDATE;
        ip->i_mode = dmode;
        tvp->v_type = VDIR;     /* Rest init'd in getnewvnode(). */
        ip->i_nlink = 2;
        if (cnp->cn_flags & ISWHITEOUT)
                ip->i_flags |= UF_OPAQUE;
        tv = time;
        error = VOP_UPDATE(tvp, &tv, &tv, 1);

        /*
         * Bump link count in parent directory
         * to reflect work done below.  Should
         * be done before reference is created
         * so reparation is possible if we crash.
         */
        dp->i_nlink++;
        dp->i_flag |= IN_CHANGE;
        if (error = VOP_UPDATE(dvp, &tv, &tv, 1))
                goto bad;

        /* Initialize directory with "." and ".." from static template. */
        if (dvp->v_mount->mnt_maxsymlinklen > 0)
                dtp = &mastertemplate;
        else
                dtp = (struct dirtemplate *)&omastertemplate;
        dirtemplate = *dtp;
        dirtemplate.dot_ino = ip->i_number;
        dirtemplate.dotdot_ino = dp->i_number;
        error = vn_rdwr(UIO_WRITE, tvp, (caddr_t)&dirtemplate,
            sizeof (dirtemplate), (off_t)0, UIO_SYSSPACE,
            IO_NODELOCKED|IO_SYNC, cnp->cn_cred, (int *)0, (struct proc *)0);
        if (error) {
                dp->i_nlink--;
                dp->i_flag |= IN_CHANGE;
                goto bad;
        }
        if (DIRBLKSIZ > VFSTOUFS(dvp->v_mount)->um_mountp->mnt_stat.f_bsize)
                panic("ufs_mkdir: blksize"); /* XXX should grow with balloc() */
        else {
                ip->i_size = DIRBLKSIZ;
                ip->i_flag |= IN_CHANGE;
        }

        /* Directory set up, now install it's entry in the parent directory. */
        if (error = ufs_direnter(ip, dvp, cnp)) {
                dp->i_nlink--;
                dp->i_flag |= IN_CHANGE;
        }
bad:
        /*
         * No need to do an explicit VOP_TRUNCATE here, vrele will do this
         * for us because we set the link count to 0.
         */
        if (error) {
                ip->i_nlink = 0;
                ip->i_flag |= IN_CHANGE;
                vput(tvp);
        } else
                *ap->a_vpp = tvp;
out:
        FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
        vput(dvp);
        return (error);
}

/*
 * Rmdir system call.
 */
int
ufs_rmdir(ap)
        struct vop_rmdir_args /* {
                struct vnode *a_dvp;
                struct vnode *a_vp;
                struct componentname *a_cnp;
        } */ *ap;
{
        struct vnode *vp = ap->a_vp;
        struct vnode *dvp = ap->a_dvp;
        struct componentname *cnp = ap->a_cnp;
        struct inode *ip, *dp;
        int error;

        ip = VTOI(vp);
        dp = VTOI(dvp);
        /*
         * No rmdir "." please.
         */
        if (dp == ip) {
                vrele(dvp);
                vput(vp);
                return (EINVAL);
        }
        /*
         * Verify the directory is empty (and valid).
         * (Rmdir ".." won't be valid since
         *  ".." will contain a reference to
         *  the current directory and thus be
         *  non-empty.)
         */
        error = 0;
        if (ip->i_nlink != 2 ||
            !ufs_dirempty(ip, dp->i_number, cnp->cn_cred)) {
                error = ENOTEMPTY;
                goto out;
        }
        if ((dp->i_flags & APPEND) || (ip->i_flags & (IMMUTABLE | APPEND))) {
                error = EPERM;
                goto out;
        }
        /*
         * Delete reference to directory before purging
         * inode.  If we crash in between, the directory
         * will be reattached to lost+found,
         */
        if (error = ufs_dirremove(dvp, cnp))
                goto out;
        dp->i_nlink--;
        dp->i_flag |= IN_CHANGE;
        cache_purge(dvp);
        vput(dvp);
        dvp = NULL;
        /*
         * Truncate inode.  The only stuff left
         * in the directory is "." and "..".  The
         * "." reference is inconsequential since
         * we're quashing it.  The ".." reference
         * has already been adjusted above.  We've
         * removed the "." reference and the reference
         * in the parent directory, but there may be
         * other hard links so decrement by 2 and
         * worry about them later.
         */
        ip->i_nlink -= 2;
        error = VOP_TRUNCATE(vp, (off_t)0, IO_SYNC, cnp->cn_cred,
            cnp->cn_proc);
        cache_purge(ITOV(ip));
out:
        if (dvp)
                vput(dvp);
        vput(vp);
        return (error);
}

/*
 * symlink -- make a symbolic link
 */
int
ufs_symlink(ap)
        struct vop_symlink_args /* {
                struct vnode *a_dvp;
                struct vnode **a_vpp;
                struct componentname *a_cnp;
                struct vattr *a_vap;
                char *a_target;
        } */ *ap;
{
        register struct vnode *vp, **vpp = ap->a_vpp;
        register struct inode *ip;
        int len, error;

        if (error = ufs_makeinode(IFLNK | ap->a_vap->va_mode, ap->a_dvp,
            vpp, ap->a_cnp))
                return (error);
        vp = *vpp;
        len = strlen(ap->a_target);
        if (len < vp->v_mount->mnt_maxsymlinklen) {
                ip = VTOI(vp);
                bcopy(ap->a_target, (char *)ip->i_shortlink, len);
                ip->i_size = len;
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
        } else
                error = vn_rdwr(UIO_WRITE, vp, ap->a_target, len, (off_t)0,
                    UIO_SYSSPACE, IO_NODELOCKED, ap->a_cnp->cn_cred, (int *)0,
                    (struct proc *)0);
        vput(vp);
        return (error);
}

/*
 * Vnode op for reading directories.
 * 
 * The routine below assumes that the on-disk format of a directory
 * is the same as that defined by <sys/dirent.h>. If the on-disk
 * format changes, then it will be necessary to do a conversion
 * from the on-disk format that read returns to the format defined
 * by <sys/dirent.h>.
 */
int
ufs_readdir(ap)
        struct vop_readdir_args /* {
                struct vnode *a_vp;
                struct uio *a_uio;
                struct ucred *a_cred;
                int *a_eofflag;
                int *ncookies;
                u_long **a_cookies;
        } */ *ap;
{
        register struct uio *uio = ap->a_uio;
        int error;
        size_t count, lost;
        off_t off = uio->uio_offset;

        count = uio->uio_resid;
        /* Make sure we don't return partial entries. */
        count -= (uio->uio_offset + count) & (DIRBLKSIZ -1);
        if (count <= 0)
                return (EINVAL);
        lost = uio->uio_resid - count;
        uio->uio_resid = count;
        uio->uio_iov->iov_len = count;
#       if (BYTE_ORDER == LITTLE_ENDIAN)
                if (ap->a_vp->v_mount->mnt_maxsymlinklen > 0) {
                        error = VOP_READ(ap->a_vp, uio, 0, ap->a_cred);
                } else {
                        struct dirent *dp, *edp;
                        struct uio auio;
                        struct iovec aiov;
                        caddr_t dirbuf;
                        int readcnt;
                        u_char tmp;

                        auio = *uio;
                        auio.uio_iov = &aiov;
                        auio.uio_iovcnt = 1;
                        auio.uio_segflg = UIO_SYSSPACE;
                        aiov.iov_len = count;
                        MALLOC(dirbuf, caddr_t, count, M_TEMP, M_WAITOK);
                        aiov.iov_base = dirbuf;
                        error = VOP_READ(ap->a_vp, &auio, 0, ap->a_cred);
                        if (error == 0) {
                                readcnt = count - auio.uio_resid;
                                edp = (struct dirent *)&dirbuf[readcnt];
                                for (dp = (struct dirent *)dirbuf; dp < edp; ) {
                                        tmp = dp->d_namlen;
                                        dp->d_namlen = dp->d_type;
                                        dp->d_type = tmp;
                                        if (dp->d_reclen > 0) {
                                                dp = (struct dirent *)
                                                    ((char *)dp + dp->d_reclen);
                                        } else {
                                                error = EIO;
                                                break;
                                        }
                                }
                                if (dp >= edp)
                                        error = uiomove(dirbuf, readcnt, uio);
                        }
                        FREE(dirbuf, M_TEMP);
                }
#       else
                error = VOP_READ(ap->a_vp, uio, 0, ap->a_cred);
#       endif
        if (!error && ap->a_ncookies != NULL) {
                struct dirent* dpStart;
                struct dirent* dpEnd;
                struct dirent* dp;
                int ncookies;
                u_long *cookies;
                u_long *cookiep;

                /*
                 * Only the NFS server uses cookies, and it loads the
                 * directory block into system space, so we can just look at
                 * it directly.
                 */
                if (uio->uio_segflg != UIO_SYSSPACE || uio->uio_iovcnt != 1)
                        panic("ufs_readdir: unexpected uio from NFS server");
                dpStart = (struct dirent *)
                     (uio->uio_iov->iov_base - (uio->uio_offset - off));
                dpEnd = (struct dirent *) uio->uio_iov->iov_base;
                for (dp = dpStart, ncookies = 0;
                     dp < dpEnd && dp->d_reclen != 0;
                     dp = (struct dirent *)((caddr_t)dp + dp->d_reclen))
                        ncookies++;
                MALLOC(cookies, u_long *, ncookies * sizeof(u_long), M_TEMP,
                    M_WAITOK);
                for (dp = dpStart, cookiep = cookies;
                     dp < dpEnd;
                     dp = (struct dirent *)((caddr_t) dp + dp->d_reclen)) {
                        off += dp->d_reclen;
                        *cookiep++ = (u_long) off;
                }
                *ap->a_ncookies = ncookies;
                *ap->a_cookies = cookies;
        }
        uio->uio_resid += lost;
        if (ap->a_eofflag)
                *ap->a_eofflag = VTOI(ap->a_vp)->i_size <= uio->uio_offset;
        return (error);
}

/*
 * Return target name of a symbolic link
 */
int
ufs_readlink(ap)
        struct vop_readlink_args /* {
                struct vnode *a_vp;
                struct uio *a_uio;
                struct ucred *a_cred;
        } */ *ap;
{
        register struct vnode *vp = ap->a_vp;
        register struct inode *ip = VTOI(vp);
        int isize;

        isize = ip->i_size;
        if (isize < vp->v_mount->mnt_maxsymlinklen) {
                uiomove((char *)ip->i_shortlink, isize, ap->a_uio);
                return (0);
        }
        return (VOP_READ(vp, ap->a_uio, 0, ap->a_cred));
}

/*
 * Ufs abort op, called after namei() when a CREATE/DELETE isn't actually
 * done. If a buffer has been saved in anticipation of a CREATE, delete it.
 */
/* ARGSUSED */
int
ufs_abortop(ap)
        struct vop_abortop_args /* {
                struct vnode *a_dvp;
                struct componentname *a_cnp;
        } */ *ap;
{
        if ((ap->a_cnp->cn_flags & (HASBUF | SAVESTART)) == HASBUF)
                FREE_ZONE(ap->a_cnp->cn_pnbuf, ap->a_cnp->cn_pnlen, M_NAMEI);
        return (0);
}

/*
 * Lock an inode. If its already locked, set the WANT bit and sleep.
 */
int
ufs_lock(ap)
        struct vop_lock_args /* {
                struct vnode *a_vp;
                int a_flags;
                struct proc *a_p;
        } */ *ap;
{
        struct vnode *vp = ap->a_vp;

        if (VTOI(vp) == (struct inode *)NULL)
                panic("inode in vnode is null\n");
        return (lockmgr(&VTOI(vp)->i_lock, ap->a_flags, &vp->v_interlock,
                ap->a_p));
}

/*
 * Unlock an inode.
 */
int
ufs_unlock(ap)
        struct vop_unlock_args /* {
                struct vnode *a_vp;
                int a_flags;
                struct proc *a_p;
        } */ *ap;
{
        struct vnode *vp = ap->a_vp;

        return (lockmgr(&VTOI(vp)->i_lock, ap->a_flags | LK_RELEASE,
                &vp->v_interlock, ap->a_p));
}

/*
 * Check for a locked inode.
 */
int
ufs_islocked(ap)
        struct vop_islocked_args /* {
                struct vnode *a_vp;
        } */ *ap;
{

        return (lockstatus(&VTOI(ap->a_vp)->i_lock));
}

/*
 * Calculate the logical to physical mapping if not done already,
 * then call the device strategy routine.
 */
int
ufs_strategy(ap)
        struct vop_strategy_args /* {
                struct buf *a_bp;
        } */ *ap;
{
        register struct buf *bp = ap->a_bp;
        register struct vnode *vp = bp->b_vp;
        register struct inode *ip;
        int error;

        ip = VTOI(vp);
    if ( !(bp->b_flags & B_VECTORLIST)) {
        if (vp->v_type == VBLK || vp->v_type == VCHR)
                panic("ufs_strategy: spec");


        if (bp->b_flags & B_PAGELIST) {
            /*
             * if we have a page list associated with this bp,
             * then go through cluste_bp since it knows how to 
             * deal with a page request that might span non-contiguous
             * physical blocks on the disk...
             */
#if 1
        if (bp->b_blkno == bp->b_lblkno) {
                if (error = VOP_BMAP(vp, bp->b_lblkno, NULL, 
                                &bp->b_blkno, NULL)) {
                                bp->b_error = error;
                                bp->b_flags |= B_ERROR;
                                biodone(bp);
                                return (error);
                }
        }
#endif /* 1 */
            error = cluster_bp(bp);
            vp = ip->i_devvp;
            bp->b_dev = vp->v_rdev;

            return (error);
        }

        if (bp->b_blkno == bp->b_lblkno) {
                if (error =
                    VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL)) {
                        bp->b_error = error;
                        bp->b_flags |= B_ERROR;
                        biodone(bp);
                        return (error);
                }
                if ((long)bp->b_blkno == -1)
                        clrbuf(bp);
        }
        if ((long)bp->b_blkno == -1) {
                biodone(bp);
                return (0);
        }

    }

        vp = ip->i_devvp;
        bp->b_dev = vp->v_rdev;
        VOCALL (vp->v_op, VOFFSET(vop_strategy), ap);
        return (0);
}

/*
 * Print out the contents of an inode.
 */
int
ufs_print(ap)
        struct vop_print_args /* {
                struct vnode *a_vp;
        } */ *ap;
{
        register struct vnode *vp = ap->a_vp;
        register struct inode *ip = VTOI(vp);

        printf("tag VT_UFS, ino %d, on dev %d, %d", ip->i_number,
                major(ip->i_dev), minor(ip->i_dev));
#if FIFO
        if (vp->v_type == VFIFO)
                fifo_printinfo(vp);
#endif /* FIFO */
        lockmgr_printinfo(&ip->i_lock);
        printf("\n");
        return (0);
}

/*
 * Read wrapper for special devices.
 */
int
ufsspec_read(ap)
        struct vop_read_args /* {
                struct vnode *a_vp;
                struct uio *a_uio;
                int  a_ioflag;
                struct ucred *a_cred;
        } */ *ap;
{

        /*
         * Set access flag.
         */
        VTOI(ap->a_vp)->i_flag |= IN_ACCESS;
        return (VOCALL (spec_vnodeop_p, VOFFSET(vop_read), ap));
}

/*
 * Write wrapper for special devices.
 */
int
ufsspec_write(ap)
        struct vop_write_args /* {
                struct vnode *a_vp;
                struct uio *a_uio;
                int  a_ioflag;
                struct ucred *a_cred;
        } */ *ap;
{

        /*
         * Set update and change flags.
         */
        VTOI(ap->a_vp)->i_flag |= IN_CHANGE | IN_UPDATE;
        return (VOCALL (spec_vnodeop_p, VOFFSET(vop_write), ap));
}

/*
 * Close wrapper for special devices.
 *
 * Update the times on the inode then do device close.
 */
int
ufsspec_close(ap)
        struct vop_close_args /* {
                struct vnode *a_vp;
                int  a_fflag;
                struct ucred *a_cred;
                struct proc *a_p;
        } */ *ap;
{
        struct vnode *vp = ap->a_vp;
        struct inode *ip = VTOI(vp);

        simple_lock(&vp->v_interlock);
        if (ap->a_vp->v_usecount > 1)
                ITIMES(ip, &time, &time);
        simple_unlock(&vp->v_interlock);
        return (VOCALL (spec_vnodeop_p, VOFFSET(vop_close), ap));
}

#if FIFO
/*
 * Read wrapper for fifo's
 */
int
ufsfifo_read(ap)
        struct vop_read_args /* {
                struct vnode *a_vp;
                struct uio *a_uio;
                int  a_ioflag;
                struct ucred *a_cred;
        } */ *ap;
{
        extern int (**fifo_vnodeop_p)(void *);

        /*
         * Set access flag.
         */
        VTOI(ap->a_vp)->i_flag |= IN_ACCESS;
        return (VOCALL (fifo_vnodeop_p, VOFFSET(vop_read), ap));
}

/*
 * Write wrapper for fifo's.
 */
int
ufsfifo_write(ap)
        struct vop_write_args /* {
                struct vnode *a_vp;
                struct uio *a_uio;
                int  a_ioflag;
                struct ucred *a_cred;
        } */ *ap;
{
        extern int (**fifo_vnodeop_p)(void *);

        /*
         * Set update and change flags.
         */
        VTOI(ap->a_vp)->i_flag |= IN_CHANGE | IN_UPDATE;
        return (VOCALL (fifo_vnodeop_p, VOFFSET(vop_write), ap));
}

/*
 * Close wrapper for fifo's.
 *
 * Update the times on the inode then do device close.
 */
ufsfifo_close(ap)
        struct vop_close_args /* {
                struct vnode *a_vp;
                int  a_fflag;
                struct ucred *a_cred;
                struct proc *a_p;
        } */ *ap;
{
        extern int (**fifo_vnodeop_p)(void *);
        struct vnode *vp = ap->a_vp;
        struct inode *ip = VTOI(vp);

        simple_lock(&vp->v_interlock);
        if (ap->a_vp->v_usecount > 1)
                ITIMES(ip, &time, &time);
        simple_unlock(&vp->v_interlock);
        return (VOCALL (fifo_vnodeop_p, VOFFSET(vop_close), ap));
}
#endif /* FIFO */

/*
 * Return POSIX pathconf information applicable to ufs filesystems.
 */
ufs_pathconf(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_NAME_MAX:
                *ap->a_retval = NAME_MAX;
                return (0);
        case _PC_PATH_MAX:
                *ap->a_retval = PATH_MAX;
                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_NO_TRUNC:
                *ap->a_retval = 1;
                return (0);
        default:
                return (EINVAL);
        }
        /* NOTREACHED */
}

/*
 * Advisory record locking support
 */
int
ufs_advlock(ap)
        struct vop_advlock_args /* {
                struct vnode *a_vp;
                caddr_t  a_id;
                int  a_op;
                struct flock *a_fl;
                int  a_flags;
        } */ *ap;
{
        register struct inode *ip = VTOI(ap->a_vp);
        register struct flock *fl = ap->a_fl;
        register struct lockf *lock;
        off_t start, end;
        int error;

        /*
         * Avoid the common case of unlocking when inode has no locks.
         */
        if (ip->i_lockf == (struct lockf *)0) {
                if (ap->a_op != F_SETLK) {
                        fl->l_type = F_UNLCK;
                        return (0);
                }
        }
        /*
         * Convert the flock structure into a start and end.
         */
        switch (fl->l_whence) {

        case SEEK_SET:
        case SEEK_CUR:
                /*
                 * Caller is responsible for adding any necessary offset
                 * when SEEK_CUR is used.
                 */
                start = fl->l_start;
                break;

        case SEEK_END:
                start = ip->i_size + fl->l_start;
                break;

        default:
                return (EINVAL);
        }
        if (start < 0)
                return (EINVAL);
        if (fl->l_len == 0)
                end = -1;
        else
                end = start + fl->l_len - 1;
        /*
         * Create the lockf structure
         */
        MALLOC(lock, struct lockf *, sizeof *lock, M_LOCKF, M_WAITOK);
        lock->lf_start = start;
        lock->lf_end = end;
        lock->lf_id = ap->a_id;
        lock->lf_inode = ip;
        lock->lf_type = fl->l_type;
        lock->lf_next = (struct lockf *)0;
        TAILQ_INIT(&lock->lf_blkhd);
        lock->lf_flags = ap->a_flags;
        /*
         * Do the requested operation.
         */
        switch(ap->a_op) {
        case F_SETLK:
                return (lf_setlock(lock));

        case F_UNLCK:
                error = lf_clearlock(lock);
                FREE(lock, M_LOCKF);
                return (error);

        case F_GETLK:
                error = lf_getlock(lock, fl);
                FREE(lock, M_LOCKF);
                return (error);
        
        default:
                _FREE(lock, M_LOCKF);
                return (EINVAL);
        }
        /* NOTREACHED */
}

/*
 * Initialize the vnode associated with a new inode, handle aliased
 * vnodes.
 */
int
ufs_vinit(mntp, specops, fifoops, vpp)
        struct mount *mntp;
        int (**specops)();
        int (**fifoops)();
        struct vnode **vpp;
{
        struct proc *p = current_proc();        /* XXX */
        struct inode *ip;
        struct vnode *vp, *nvp;

        vp = *vpp;
        ip = VTOI(vp);
        switch(vp->v_type = IFTOVT(ip->i_mode)) {
        case VCHR:
        case VBLK:
                vp->v_op = specops;
                if (nvp = checkalias(vp, ip->i_rdev, mntp)) {
                        /*
                         * Discard unneeded vnode, but save its inode.
                         * Note that the lock is carried over in the inode
                         * to the replacement vnode.
                         */
                        nvp->v_data = vp->v_data;
                        vp->v_data = NULL;
                        vp->v_op = spec_vnodeop_p;
                        vrele(vp);
                        vgone(vp);
                        /*
                         * Reinitialize aliased inode.
                         */
                        vp = nvp;
                        ip->i_vnode = vp;
                }
                break;
        case VFIFO:
#if FIFO
                vp->v_op = fifoops;
                break;
#else
                return (EOPNOTSUPP);
#endif
        case VREG:
#if 0
                ubc_info_init(vp);
#endif /* 0 */
                break;
        default:
                break;
        }
        if (ip->i_number == ROOTINO)
                vp->v_flag |= VROOT;
        /*
         * Initialize modrev times
         */
        SETHIGH(ip->i_modrev, time.tv_sec);
        SETLOW(ip->i_modrev, time.tv_usec * 4294);
        *vpp = vp;
        return (0);
}

/*
 * Allocate a new inode.
 */
int
ufs_makeinode(mode, dvp, vpp, cnp)
        int mode;
        struct vnode *dvp;
        struct vnode **vpp;
        struct componentname *cnp;
{
        register struct inode *ip, *pdir;
        struct timeval tv;
        struct vnode *tvp;
        int error;

        pdir = VTOI(dvp);
#if DIAGNOSTIC
        if ((cnp->cn_flags & HASBUF) == 0)
                panic("ufs_makeinode: no name");
#endif
        *vpp = NULL;
        if ((mode & IFMT) == 0)
                mode |= IFREG;

        if (error = VOP_VALLOC(dvp, mode, cnp->cn_cred, &tvp)) {
                _FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
                vput(dvp);
                return (error);
        }
        ip = VTOI(tvp);
        ip->i_gid = pdir->i_gid;
        if ((mode & IFMT) == IFLNK)
                ip->i_uid = pdir->i_uid;
        else
                ip->i_uid = cnp->cn_cred->cr_uid;
#if QUOTA
        if ((error = getinoquota(ip)) ||
            (error = chkiq(ip, 1, cnp->cn_cred, 0))) {
                _FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
                VOP_VFREE(tvp, ip->i_number, mode);
                vput(tvp);
                vput(dvp);
                return (error);
        }
#endif
        ip->i_flag |= IN_ACCESS | IN_CHANGE | IN_UPDATE;
        ip->i_mode = mode;
        tvp->v_type = IFTOVT(mode);     /* Rest init'd in getnewvnode(). */
        ip->i_nlink = 1;
        if ((ip->i_mode & ISGID) && !groupmember(ip->i_gid, cnp->cn_cred) &&
            suser(cnp->cn_cred, NULL))
                ip->i_mode &= ~ISGID;

        if (cnp->cn_flags & ISWHITEOUT)
                ip->i_flags |= UF_OPAQUE;

        /*
         * initialize UBC before calling VOP_UPDATE and ufs_direnter
         * Not doing so introduces probelms in handling error from
         * those calls.
         * It results in a "vget: stolen ubc_info" panic due to attempt
         * to shutdown uninitialized UBC.
         */
        if (UBCINFOMISSING(tvp) || UBCINFORECLAIMED(tvp))
                ubc_info_init(tvp);

        /*
         * Make sure inode goes to disk before directory entry.
         */
        tv = time;
        if (error = VOP_UPDATE(tvp, &tv, &tv, 1))
                goto bad;
        if (error = ufs_direnter(ip, dvp, cnp))
                goto bad;
        if ((cnp->cn_flags & SAVESTART) == 0)
                FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
        vput(dvp);

        *vpp = tvp;
        return (0);

bad:
        /*
         * Write error occurred trying to update the inode
         * or the directory so must deallocate the inode.
         */
        _FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
        vput(dvp);
        ip->i_nlink = 0;
        ip->i_flag |= IN_CHANGE;
        vput(tvp);
        return (error);
}