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ufs_vnops.c

/*    $OpenBSD: ufs_vnops.c,v 1.67 2005/07/24 05:43:36 millert Exp $    */
/*    $NetBSD: ufs_vnops.c,v 1.18 1996/05/11 18:28:04 mycroft Exp $     */

/*
 * Copyright (c) 1982, 1986, 1989, 1993
 *    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. 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   8.14 (Berkeley) 10/26/94
 */

#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/pool.h>
#include <sys/dirent.h>
#include <sys/lockf.h>
#include <sys/event.h>
#include <sys/poll.h>

#include <uvm/uvm_extern.h>

#include <miscfs/specfs/specdev.h>
#include <miscfs/fifofs/fifo.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>
#ifdef UFS_DIRHASH
#include <ufs/ufs/dirhash.h>
#endif
#include <ufs/ext2fs/ext2fs_extern.h>

static int ufs_chmod(struct vnode *, int, struct ucred *, struct proc *);
static int ufs_chown(struct vnode *, uid_t, gid_t, struct ucred *, struct proc *);
int filt_ufsread(struct knote *kn, long hint);
int filt_ufswrite(struct knote *kn, long hint);
int filt_ufsvnode(struct knote *kn, long hint);
void filt_ufsdetach(struct knote *kn);

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; \
}
#define VN_KNOTE(vp, b) \
      KNOTE(&vp->v_selectinfo.vsi_selinfo.si_note, (b))


/*
 * 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, ".."
};

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

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

/*
 * Mknod vnode call
 */
/* ARGSUSED */
int
ufs_mknod(v)
      void *v;
{
      struct vop_mknod_args /* {
                         struct vnode *a_dvp;
                         struct vnode **a_vpp;
                         struct componentname *a_cnp;
                         struct vattr *a_vap;
                         } */ *ap = v;
      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)) != 0)
            return (error);
      VN_KNOTE(ap->a_dvp, NOTE_WRITE);
      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_ffs_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(v)
      void *v;
{
      struct vop_open_args /* {
                        struct vnode *a_vp;
                        int  a_mode;
                        struct ucred *a_cred;
                        struct proc *a_p;
      } */ *ap = v;
      struct inode *ip = VTOI(ap->a_vp);

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

      if (ap->a_mode & O_TRUNC)
            ip->i_flag |= IN_CHANGE | IN_UPDATE;

      return (0);
}

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

      simple_lock(&vp->v_interlock);
      if (vp->v_usecount > 1)
            ITIMES(ip, &time, &time);
      simple_unlock(&vp->v_interlock);
      return (0);
}

int
ufs_access(v)
      void *v;
{
      struct vop_access_args /* {
            struct vnode *a_vp;
            int  a_mode;
            struct ucred *a_cred;
            struct proc *a_p;
      } */ *ap = v;
      struct vnode *vp = ap->a_vp;
      struct inode *ip = VTOI(vp);
      mode_t mode = ap->a_mode;

      /*
       * 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) {
                  int error;
            case VDIR:
            case VLNK:
            case VREG:
                  if (vp->v_mount->mnt_flag & MNT_RDONLY)
                        return (EROFS);

                  if ((error = getinoquota(ip)) != 0)
                        return (error);
                  break;
            case VBAD:
            case VBLK:
            case VCHR:
            case VSOCK:
            case VFIFO:
            case VNON:
                  break;

            }
      }

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

      return (vaccess(ip->i_ffs_mode, ip->i_ffs_uid, ip->i_ffs_gid,
                              mode, ap->a_cred));
}

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

      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_ffs_mode & ~IFMT;
      vap->va_nlink = ip->i_effnlink;
      vap->va_uid = ip->i_ffs_uid;
      vap->va_gid = ip->i_ffs_gid;
      vap->va_rdev = (dev_t)ip->i_ffs_rdev;
      vap->va_size = ip->i_ffs_size;
      vap->va_atime.tv_sec = ip->i_ffs_atime;
      vap->va_atime.tv_nsec = ip->i_ffs_atimensec;
      vap->va_mtime.tv_sec = ip->i_ffs_mtime;
      vap->va_mtime.tv_nsec = ip->i_ffs_mtimensec;
      vap->va_ctime.tv_sec = ip->i_ffs_ctime;
      vap->va_ctime.tv_nsec = ip->i_ffs_ctimensec;
      vap->va_flags = ip->i_ffs_flags;
      vap->va_gen = ip->i_ffs_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 = MAXBSIZE;
      else
            vap->va_blocksize = vp->v_mount->mnt_stat.f_iosize;
      vap->va_bytes = dbtob((u_quad_t)ip->i_ffs_blocks);
      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(v)
      void *v;
{
      struct vop_setattr_args /* {
            struct vnode *a_vp;
            struct vattr *a_vap;
            struct ucred *a_cred;
            struct proc *a_p;
      } */ *ap = v;
      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;
      int error;
      long hint = NOTE_ATTRIB;
      u_quad_t oldsize;

      /*
       * 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_ffs_uid &&
                (error = suser_ucred(cred)))
                  return (error);
            if (cred->cr_uid == 0) {
                  if ((ip->i_ffs_flags & (SF_IMMUTABLE | SF_APPEND)) &&
                      securelevel > 0)
                        return (EPERM);
                  ip->i_ffs_flags = vap->va_flags;
            } else {
                  if (ip->i_ffs_flags & (SF_IMMUTABLE | SF_APPEND) ||
                      (vap->va_flags & UF_SETTABLE) != vap->va_flags)
                        return (EPERM);
                  ip->i_ffs_flags &= SF_SETTABLE;
                  ip->i_ffs_flags |= (vap->va_flags & UF_SETTABLE);
            }
            ip->i_flag |= IN_CHANGE;
            if (vap->va_flags & (IMMUTABLE | APPEND))
                  return (0);
      }
      if (ip->i_ffs_flags & (IMMUTABLE | APPEND))
            return (EPERM);
      /*
       * Go through the fields and update if 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);
            error = ufs_chown(vp, vap->va_uid, vap->va_gid, cred, p);
            if (error)
                  return (error);
      }
      if (vap->va_size != VNOVAL) {
            oldsize = ip->i_ffs_size;
            /*
             * 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;
            default:
                  break;
            }
            if ((error = UFS_TRUNCATE(ip, vap->va_size, 0, cred)) != 0)
                  return (error);
            if (vap->va_size < oldsize)
                  hint |= NOTE_TRUNCATE;
      }
      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_ffs_uid &&
                (error = suser_ucred(cred)) &&
                ((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;
            error = UFS_UPDATE2(ip, &vap->va_atime, &vap->va_mtime, 0);
            if (error)
                  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);
      }
      VN_KNOTE(vp, hint);
      return (error);
}

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

      if (cred->cr_uid != ip->i_ffs_uid &&
          (error = suser_ucred(cred)))
            return (error);
      if (cred->cr_uid) {
            if (vp->v_type != VDIR && (mode & S_ISTXT))
                  return (EFTYPE);
            if (!groupmember(ip->i_ffs_gid, cred) && (mode & ISGID))
                  return (EPERM);
      }
      ip->i_ffs_mode &= ~ALLPERMS;
      ip->i_ffs_mode |= (mode & ALLPERMS);
      ip->i_flag |= IN_CHANGE;
      if ((vp->v_flag & VTEXT) && (ip->i_ffs_mode & S_ISTXT) == 0)
            (void) uvm_vnp_uncache(vp);
      return (0);
}

/*
 * Perform chown operation on inode ip;
 * inode must be locked prior to call.
 */
static int
ufs_chown(vp, uid, gid, cred, p)
      struct vnode *vp;
      uid_t uid;
      gid_t gid;
      struct ucred *cred;
      struct proc *p;
{
      struct inode *ip = VTOI(vp);
      uid_t ouid;
      gid_t ogid;
      int error = 0;
      daddr_t change;
      enum ufs_quota_flags quota_flags = 0;

      if (uid == (uid_t)VNOVAL)
            uid = ip->i_ffs_uid;
      if (gid == (gid_t)VNOVAL)
            gid = ip->i_ffs_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_ffs_uid || uid != ip->i_ffs_uid ||
          (gid != ip->i_ffs_gid && !groupmember((gid_t)gid, cred))) &&
          (error = suser_ucred(cred)))
            return (error);
      ogid = ip->i_ffs_gid;
      ouid = ip->i_ffs_uid;
      change = ip->i_ffs_blocks;

      if (ouid == uid)
            quota_flags |= UFS_QUOTA_NOUID;
      
      if (ogid == gid)
            quota_flags |= UFS_QUOTA_NOGID;

      if ((error = getinoquota(ip)) != 0)
            return (error);
      (void) ufs_quota_free_blocks2(ip, change, cred, quota_flags);
      (void) ufs_quota_free_inode2(ip, cred, quota_flags);
      (void) ufs_quota_delete(ip);

      ip->i_ffs_gid = gid;
      ip->i_ffs_uid = uid;

      if ((error = getinoquota(ip)) != 0)
            goto error;

      if ((error = ufs_quota_alloc_blocks2(ip, change, cred, 
             quota_flags)) != 0) 
            goto error;

      if ((error = ufs_quota_alloc_inode2(ip, cred ,
             quota_flags)) != 0) {
            (void)ufs_quota_free_blocks2(ip, change, cred, 
                quota_flags);       
            goto error;
      }

      if (getinoquota(ip))
            panic("chown: lost quota");

      if (ouid != uid || ogid != gid)
            ip->i_flag |= IN_CHANGE;
      if (ouid != uid && cred->cr_uid != 0)
            ip->i_ffs_mode &= ~ISUID;
      if (ogid != gid && cred->cr_uid != 0)
            ip->i_ffs_mode &= ~ISGID;
      return (0);

error:
      (void) ufs_quota_delete(ip);

      ip->i_ffs_gid = ogid;
      ip->i_ffs_uid = ouid;
      if (getinoquota(ip) == 0) {
            (void) ufs_quota_alloc_blocks2(ip, change, cred, 
                quota_flags | UFS_QUOTA_FORCE);
            (void) ufs_quota_alloc_inode2(ip, cred,
                quota_flags | UFS_QUOTA_FORCE);
            (void) getinoquota(ip);
      }
      return (error);

}

/* ARGSUSED */
int
ufs_ioctl(v)
      void *v;
{
#if 0
      struct vop_ioctl_args /* {
            struct vnode *a_vp;
            u_long a_command;
            caddr_t  a_data;
            int  a_fflag;
            struct ucred *a_cred;
            struct proc *a_p;
      } */ *ap = v;
#endif
      return (ENOTTY);
}

/* ARGSUSED */
int
ufs_poll(v)
      void *v;
{
      struct vop_poll_args /* {
            struct vnode *a_vp;
            int  a_events;
            struct proc *a_p;
      } */ *ap = v;

      /*
       * We should really check to see if I/O is possible.
       */
      return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
}

/*
 * Seek on a file
 *
 * Nothing to do, so just return.
 */
/* ARGSUSED */
int
ufs_seek(v)
      void *v;
{
#if 0
      struct vop_seek_args /* {
            struct vnode *a_vp;
            off_t  a_oldoff;
            off_t  a_newoff;
            struct ucred *a_cred;
      } */ *ap = v;
#endif

      return (0);
}

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

      ip = VTOI(vp);
      if (vp->v_type == VDIR || (ip->i_ffs_flags & (IMMUTABLE | APPEND)) ||
          (VTOI(dvp)->i_ffs_flags & APPEND)) {
            error = EPERM;
            goto out;
      }
      error = ufs_dirremove(dvp, ip, ap->a_cnp->cn_flags, 0);
      VN_KNOTE(vp, NOTE_DELETE);
      VN_KNOTE(dvp, NOTE_WRITE);
 out:
      if (dvp == vp)
            vrele(vp);
      else
            vput(vp);
      vput(dvp);
      return (error);
}

/*
 * link vnode call
 */
int
ufs_link(v)
      void *v;
{
      struct vop_link_args /* {
            struct vnode *a_dvp;
            struct vnode *a_vp;
            struct componentname *a_cnp;
      } */ *ap = v;
      struct vnode *dvp = ap->a_dvp;
      struct vnode *vp = ap->a_vp;
      struct componentname *cnp = ap->a_cnp;
      struct proc *p = cnp->cn_proc;
      struct inode *ip;
      struct direct newdir;
      int error;

#ifdef DIAGNOSTIC
      if ((cnp->cn_flags & HASBUF) == 0)
            panic("ufs_link: no name");
#endif
      if (vp->v_type == VDIR) {
            VOP_ABORTOP(dvp, cnp);
            error = EPERM;
            goto out2;
      }
      if (dvp->v_mount != vp->v_mount) {
            VOP_ABORTOP(dvp, cnp);
            error = EXDEV;
            goto out2;
      }
      if (dvp != vp && (error = vn_lock(vp, LK_EXCLUSIVE, p))) {
            VOP_ABORTOP(dvp, cnp);
            goto out2;
      }
      ip = VTOI(vp);
      if ((nlink_t)ip->i_ffs_nlink >= LINK_MAX) {
            VOP_ABORTOP(dvp, cnp);
            error = EMLINK;
            goto out1;
      }
      if (ip->i_ffs_flags & (IMMUTABLE | APPEND)) {
            VOP_ABORTOP(dvp, cnp);
            error = EPERM;
            goto out1;
      }
      ip->i_effnlink++;
      ip->i_ffs_nlink++;
      ip->i_flag |= IN_CHANGE;
      if (DOINGSOFTDEP(vp))
            softdep_change_linkcnt(ip, 0);
      if ((error = UFS_UPDATE(ip, !DOINGSOFTDEP(vp))) == 0) {
            ufs_makedirentry(ip, cnp, &newdir);
            error = ufs_direnter(dvp, vp, &newdir, cnp, NULL);
      }
      if (error) {
            ip->i_effnlink--;
            ip->i_ffs_nlink--;
            ip->i_flag |= IN_CHANGE;
            if (DOINGSOFTDEP(vp))
                  softdep_change_linkcnt(ip, 0);
      }
      pool_put(&namei_pool, cnp->cn_pnbuf);
      VN_KNOTE(vp, NOTE_LINK);
      VN_KNOTE(dvp, NOTE_WRITE);
out1:
      if (dvp != vp)
            VOP_UNLOCK(vp, 0, p);
out2:
      vput(dvp);
      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(v)
      void *v;
{
      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 = v;
      struct vnode *tvp = ap->a_tvp;
      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 direct newdir;
      int doingdirectory = 0, oldparent = 0, newparent = 0;
      int error = 0;

#ifdef 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);
      }

      if (tvp && ((VTOI(tvp)->i_ffs_flags & (IMMUTABLE | APPEND)) ||
          (VTOI(tdvp)->i_ffs_flags & APPEND))) {
            error = EPERM;
            goto abortit;
      }

      /*
       * Check if just deleting a link name or if we've lost a race.
       * If another process completes the same rename after we've looked
       * up the source and have blocked looking up the target, then the
       * source and target inodes may be identical now although the
       * names were never linked.
       */
      if (fvp == tvp) {
            if (fvp->v_type == VDIR) {
                  /*
                   * Linked directories are impossible, so we must
                   * have lost the race.  Pretend that the rename
                   * completed before the lookup.
                   */
                  error = ENOENT;
                  goto abortit;
            }

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

            /*
             * Delete source.  There is another race now that everything
             * is unlocked, but this doesn't cause any new complications.
             * relookup() may find a file that is unrelated to the
             * original one, or it may fail.  Too bad.
             */
            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;
            if ((error = relookup(fdvp, &fvp, fcnp)) != 0)
                  return (error);         /* relookup did vrele() */
            vrele(fdvp);
            return (VOP_REMOVE(fdvp, fvp, fcnp));
      }

      if ((error = vn_lock(fvp, LK_EXCLUSIVE, p)) != 0)
            goto abortit;

      /* fvp, tdvp, tvp now locked */
      dp = VTOI(fdvp);
      ip = VTOI(fvp);
      if ((nlink_t)ip->i_ffs_nlink >= LINK_MAX) {
            VOP_UNLOCK(fvp, 0, p);
            error = EMLINK;
            goto abortit;
      }
      if ((ip->i_ffs_flags & (IMMUTABLE | APPEND)) ||
          (dp->i_ffs_flags & APPEND)) {
            VOP_UNLOCK(fvp, 0, p);
            error = EPERM;
            goto abortit;
      }
      if ((ip->i_ffs_mode & IFMT) == IFDIR) {
            error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_proc);
            if (!error && tvp)
                  error = VOP_ACCESS(tvp, VWRITE, tcnp->cn_cred, tcnp->cn_proc);
            if (error) {
                  VOP_UNLOCK(fvp, 0, p);
                  error = EACCES;
                  goto abortit;
            }
            /*
             * Avoid ".", "..", and aliases of "." for obvious reasons.
             */
            if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
                dp == ip ||
                (fcnp->cn_flags & ISDOTDOT) ||
                (tcnp->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 = 1;
      }
      VN_KNOTE(fdvp, NOTE_WRITE);         /* XXX right place? */

      /*
       * 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_effnlink++;
      ip->i_ffs_nlink++;
      ip->i_flag |= IN_CHANGE;
      if (DOINGSOFTDEP(fvp))
            softdep_change_linkcnt(ip, 0);
      if ((error = UFS_UPDATE(ip, !DOINGSOFTDEP(fvp))) != 0) {
            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 hierarchy 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);

      /* tdvp and tvp locked */
      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);
            /*
             * Compensate for the reference ufs_checkpath() loses.
             */
            vref(tdvp);
            /* Only tdvp is locked */
            if ((error = ufs_checkpath(ip, dp, tcnp->cn_cred)) != 0)
                  goto out;
            if ((tcnp->cn_flags & SAVESTART) == 0)
                  panic("ufs_rename: lost to startdir");
            if ((error = relookup(tdvp, &tvp, tcnp)) != 0)
                  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_ffs_nlink >= LINK_MAX) {
                        error = EMLINK;
                        goto bad;
                  }
                  dp->i_effnlink++;
                  dp->i_ffs_nlink++;
                  dp->i_flag |= IN_CHANGE;
                  if (DOINGSOFTDEP(tdvp))
                               softdep_change_linkcnt(dp, 0);
                  if ((error = UFS_UPDATE(dp, !DOINGSOFTDEP(tdvp))) 
                      != 0) {
                        dp->i_effnlink--;
                        dp->i_ffs_nlink--;
                        dp->i_flag |= IN_CHANGE;
                        if (DOINGSOFTDEP(tdvp))
                              softdep_change_linkcnt(dp, 0);
                        goto bad;
                  }
            }
            ufs_makedirentry(ip, tcnp, &newdir);
            if ((error = ufs_direnter(tdvp, NULL, &newdir, tcnp, NULL)) != 0) {
                  if (doingdirectory && newparent) {
                        dp->i_effnlink--;
                        dp->i_ffs_nlink--;
                        dp->i_flag |= IN_CHANGE;
                        if (DOINGSOFTDEP(tdvp))
                              softdep_change_linkcnt(dp, 0);
                        (void)UFS_UPDATE(dp, 1);
                  }
                  goto bad;
            }
            VN_KNOTE(tdvp, NOTE_WRITE);
            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("ufs_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_ffs_mode & S_ISTXT) && tcnp->cn_cred->cr_uid != 0 &&
                tcnp->cn_cred->cr_uid != dp->i_ffs_uid &&
                xp->i_ffs_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_ffs_mode & IFMT) == IFDIR) {
                  if (xp->i_effnlink > 2 ||
                      !ufs_dirempty(xp, dp->i_number, tcnp->cn_cred)) {
                        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, xp, ip->i_number,
                   IFTODT(ip->i_ffs_mode), (doingdirectory && newparent) ?
               newparent : doingdirectory)) != 0)
                        goto bad;
            if (doingdirectory) {
                  if (!newparent) {
                        dp->i_effnlink--;
                        if (DOINGSOFTDEP(tdvp))
                              softdep_change_linkcnt(dp, 0);
                  }
                  xp->i_effnlink--;
                  if (DOINGSOFTDEP(tvp))
                        softdep_change_linkcnt(xp, 0);
            }
            if (doingdirectory && !DOINGSOFTDEP(tvp)) {
                   /*
                  * Truncate inode. The only stuff left in the directory
                  * is "." and "..". The "." reference is inconsequential
                        * since we are quashing it. We have removed the "."
                        * reference and the reference in the parent directory,
                        * but there may be other hard links. The soft
                        * dependency code will arrange to do these operations
                        * after the parent directory entry has been deleted on
                        * disk, so when running with that code we avoid doing
                        * them now.
                        */
                  if (!newparent) {
                        dp->i_ffs_nlink--;
                        dp->i_flag |= IN_CHANGE;
                  }

                  xp->i_ffs_nlink--;
                  xp->i_flag |= IN_CHANGE;
                  if ((error = UFS_TRUNCATE(VTOI(tvp), (off_t)0, IO_SYNC,
                          tcnp->cn_cred)) != 0)
                        goto bad;
                }
            VN_KNOTE(tdvp, NOTE_WRITE);
              vput(tdvp);
            VN_KNOTE(tvp, NOTE_DELETE);
            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");
      if ((error = relookup(fdvp, &fvp, fcnp)) != 0) {
            vrele(ap->a_fvp);
            return (error);
      }
      vrele(fdvp);
      if (fvp == NULL) {
            /*
             * From name has disappeared.
             */
            if (doingdirectory)
                  panic("ufs_rename: lost dir entry");
            vrele(ap->a_fvp);
            return (0);
      }

      xp = VTOI(fvp);
      dp = VTOI(fdvp);

      /*
       * 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; the IN_RENAME 
       * flag ensures that it cannot be moved by another rename or removed
       * by a rmdir.
       */
      if (xp != ip) {
            if (doingdirectory)
                  panic("ufs_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) {
                  xp->i_offset = mastertemplate.dot_reclen;
                  ufs_dirrewrite(xp, dp, newparent, DT_DIR, 0);
                  cache_purge(fdvp);
            }
            error = ufs_dirremove(fdvp, xp, fcnp->cn_flags, 0);
            xp->i_flag &= ~IN_RENAME;
      }
      VN_KNOTE(fvp, NOTE_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:
      vrele(fdvp);
      if (doingdirectory)
            ip->i_flag &= ~IN_RENAME;
      if (vn_lock(fvp, LK_EXCLUSIVE, p) == 0) {
            ip->i_effnlink--;
            ip->i_ffs_nlink--;
            ip->i_flag |= IN_CHANGE;
            ip->i_flag &= ~IN_RENAME;
            if (DOINGSOFTDEP(fvp))
                  softdep_change_linkcnt(ip, 0);
            vput(fvp);
      } else
            vrele(fvp);
      return (error);
}

/*
 * Mkdir system call
 */
int
ufs_mkdir(v)
      void *v;
{
      struct vop_mkdir_args /* {
            struct vnode *a_dvp;
            struct vnode **a_vpp;
            struct componentname *a_cnp;
            struct vattr *a_vap;
      } */ *ap = v;
      struct vnode *dvp = ap->a_dvp;
      struct vattr *vap = ap->a_vap;
      struct componentname *cnp = ap->a_cnp;
      struct inode *ip, *dp;
      struct vnode *tvp;
      struct buf *bp;
      struct direct newdir;
      struct dirtemplate dirtemplate, *dtp;
      int error, dmode, blkoff;

#ifdef DIAGNOSTIC
      if ((cnp->cn_flags & HASBUF) == 0)
            panic("ufs_mkdir: no name");
#endif
      dp = VTOI(dvp);
      if ((nlink_t)dp->i_ffs_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 = UFS_INODE_ALLOC(dp, dmode, cnp->cn_cred, &tvp)) != 0)
            goto out;
      ip = VTOI(tvp);
      ip->i_ffs_uid = cnp->cn_cred->cr_uid;
      ip->i_ffs_gid = dp->i_ffs_gid;

      if ((error = getinoquota(ip)) ||
          (error = ufs_quota_alloc_inode(ip, cnp->cn_cred))) {
            pool_put(&namei_pool, cnp->cn_pnbuf);
            UFS_INODE_FREE(ip, ip->i_number, dmode);
            vput(tvp);
            vput(dvp);
            return (error);
      }

      ip->i_flag |= IN_ACCESS | IN_CHANGE | IN_UPDATE;
      ip->i_ffs_mode = dmode;
      tvp->v_type = VDIR;     /* Rest init'd in getnewvnode(). */
      ip->i_effnlink = 2;
      ip->i_ffs_nlink = 2;
      if (DOINGSOFTDEP(tvp))
            softdep_change_linkcnt(ip, 0);

      /*
       * Bump link count in parent directory to reflect work done below.
       * Should be done before reference is create so cleanup is 
       * possible if we crash.
       */
      dp->i_effnlink++;
      dp->i_ffs_nlink++;
      dp->i_flag |= IN_CHANGE;
      if (DOINGSOFTDEP(dvp))
            softdep_change_linkcnt(dp, 0);
      if ((error = UFS_UPDATE(dp, !DOINGSOFTDEP(dvp))) != 0)
            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;

      if ((error = UFS_BUF_ALLOC(ip, (off_t)0, DIRBLKSIZ, cnp->cn_cred,
            B_CLRBUF, &bp)) != 0)
            goto bad;
      ip->i_ffs_size = DIRBLKSIZ;
      ip->i_flag |= IN_CHANGE | IN_UPDATE;
      uvm_vnp_setsize(tvp, ip->i_ffs_size);
      bcopy((caddr_t)&dirtemplate, (caddr_t)bp->b_data, sizeof dirtemplate);
      if (DOINGSOFTDEP(tvp)) {
            /*
             * Ensure that the entire newly allocated block is a
             * valid directory so that future growth within the
             * block does not have to ensure that the block is
             * written before the inode
             */
            blkoff = DIRBLKSIZ;
            while (blkoff < bp->b_bcount) {
                  ((struct direct *)
                   (bp->b_data + blkoff))->d_reclen = DIRBLKSIZ;
                  blkoff += DIRBLKSIZ;
            }
      }
      if ((error = UFS_UPDATE(ip, !DOINGSOFTDEP(tvp))) != 0) {
            (void)VOP_BWRITE(bp);
            goto bad;
      }

      /*
         * Directory set up, now install it's entry in the parent directory.
         *
         * If we are not doing soft dependencies, then we must write out the
         * buffer containing the new directory body before entering the new
         * name in the parent. If we are doing soft dependencies, then the
         * buffer containing the new directory body will be passed to and
         * released in the soft dependency code after the code has attached
         * an appropriate ordering dependency to the buffer which ensures that
         * the buffer is written before the new name is written in the parent.
       */
        if (!DOINGSOFTDEP(dvp) && ((error = VOP_BWRITE(bp)) != 0))
                goto bad;
        ufs_makedirentry(ip, cnp, &newdir);
        error = ufs_direnter(dvp, tvp, &newdir, cnp, bp);
  
bad:
        if (error == 0) {
            VN_KNOTE(dvp, NOTE_WRITE);
                *ap->a_vpp = tvp;
        } else {
                dp->i_effnlink--;
                dp->i_ffs_nlink--;
                dp->i_flag |= IN_CHANGE;
            if (DOINGSOFTDEP(dvp))
                  softdep_change_linkcnt(dp, 0);
                /*
                 * No need to do an explicit VOP_TRUNCATE here, vrele will
                 * do this for us because we set the link count to 0.
                 */
                ip->i_effnlink = 0;
                ip->i_ffs_nlink = 0;
                ip->i_flag |= IN_CHANGE;
            if (DOINGSOFTDEP(tvp))
                  softdep_change_linkcnt(ip, 0);
            vput(tvp);
      }
out:
      pool_put(&namei_pool, cnp->cn_pnbuf);
      vput(dvp);

      return (error);
}

/*
 * Rmdir system call.
 */
int
ufs_rmdir(v)
      void *v;
{
      struct vop_rmdir_args /* {
            struct vnode *a_dvp;
            struct vnode *a_vp;
            struct componentname *a_cnp;
      } */ *ap = v;
      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 "." or of mounted on directories.
       */
      if (dp == ip || vp->v_mountedhere != 0) {
            if (dp == ip)
                  vrele(dvp);
            else
                  vput(dvp);
            vput(vp);
            return (EINVAL);
      }
      /*
         * Do not remove a directory that is in the process of being renamed.
         * Verify the directory is empty (and valid). Rmdir ".." will not be
         * valid since ".." will contain a reference to the current directory
         * and thus be non-empty.
       */
      error = 0;
      if (ip->i_flag & IN_RENAME) {
            error = EINVAL;
            goto out;
      }
      if (ip->i_effnlink != 2 ||
          !ufs_dirempty(ip, dp->i_number, cnp->cn_cred)) {
            error = ENOTEMPTY;
            goto out;
      }
      if ((dp->i_ffs_flags & APPEND) ||
            (ip->i_ffs_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,
       */
      dp->i_effnlink--;
      ip->i_effnlink--;
      if (DOINGSOFTDEP(vp)) {
            softdep_change_linkcnt(dp, 0);
            softdep_change_linkcnt(ip, 0);
      }
      if ((error = ufs_dirremove(dvp, ip, cnp->cn_flags, 1)) != 0) {
            dp->i_effnlink++;
            ip->i_effnlink++;
            if (DOINGSOFTDEP(vp)) {
                  softdep_change_linkcnt(dp, 0);
                  softdep_change_linkcnt(ip, 0);
            }
            goto out;
      }

      VN_KNOTE(dvp, NOTE_WRITE | NOTE_LINK);
      cache_purge(dvp);
        /*
       * Truncate inode. The only stuff left in the directory is "." and
       * "..". The "." reference is inconsequential since we are quashing
       * it. The soft dependency code will arrange to do these operations
       * after the parent directory entry has been deleted on disk, so
       * when running with that code we avoid doing them now.
       */
      if (!DOINGSOFTDEP(vp)) {
            int ioflag;

            dp->i_ffs_nlink--;
            dp->i_flag |= IN_CHANGE;
            ip->i_ffs_nlink--;
            ip->i_flag |= IN_CHANGE;
            ioflag = DOINGASYNC(vp) ? 0 : IO_SYNC;
            error = UFS_TRUNCATE(ip, (off_t)0, ioflag, cnp->cn_cred);
      }
      cache_purge(vp);
#ifdef UFS_DIRHASH
      /* Kill any active hash; i_effnlink == 0, so it will not come back. */
      if (ip->i_dirhash != NULL)
            ufsdirhash_free(ip);
#endif

out:
      VN_KNOTE(vp, NOTE_DELETE);
        vput(dvp);
      vput(vp);
      return (error);
}

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

      error = ufs_makeinode(IFLNK | ap->a_vap->va_mode, ap->a_dvp,
                        vpp, ap->a_cnp);
      if (error)
            return (error);
      VN_KNOTE(ap->a_dvp, NOTE_WRITE);
      vp = *vpp;
      len = strlen(ap->a_target);
      if (len < vp->v_mount->mnt_maxsymlinklen) {
            ip = VTOI(vp);
            bcopy(ap->a_target, (char *)ip->i_ffs_shortlink, len);
            ip->i_ffs_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, NULL,
                (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(v)
      void *v;
{
      struct vop_readdir_args /* {
            struct vnode *a_vp;
            struct uio *a_uio;
            struct ucred *a_cred;
            int *a_eofflag;
            u_long **a_cookies;
            int *ncookies;
      } */ *ap = v;
      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) {
            struct dirent *dp, *dpstart;
            off_t offstart;
            u_long *cookies;
            int ncookies;

            /*
             * Only the NFS server and emulations use cookies, and they
             * load 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: lost in space");

            dpstart = (struct dirent *)
                  (uio->uio_iov->iov_base - (uio->uio_offset - off));
                offstart = off;
                for (dp = dpstart, ncookies = 0; off < uio->uio_offset; ) {
                        if (dp->d_reclen == 0)
                                break;
                        off += dp->d_reclen;
                        ncookies++;
                        dp = (struct dirent *)((caddr_t)dp + dp->d_reclen);
                }
                lost += uio->uio_offset - off;
                uio->uio_offset = off;
                MALLOC(cookies, u_long *, ncookies * sizeof(u_long), M_TEMP,
                    M_WAITOK);
                *ap->a_ncookies = ncookies;
                *ap->a_cookies = cookies;
                for (off = offstart, dp = dpstart; off < uio->uio_offset; ) {
                  off += dp->d_reclen;
                        *cookies = off;
                  cookies++;
                        dp = (struct dirent *)((caddr_t)dp + dp->d_reclen);
            }
      }
      uio->uio_resid += lost;
      *ap->a_eofflag = VTOI(ap->a_vp)->i_ffs_size <= uio->uio_offset;
      return (error);
}

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

      isize = ip->i_ffs_size;
      if (isize < vp->v_mount->mnt_maxsymlinklen ||
          (vp->v_mount->mnt_maxsymlinklen == 0 && ip->i_ffs_blocks == 0)) {
            uiomove((char *)ip->i_ffs_shortlink, isize, ap->a_uio);
            return (0);
      }
      return (VOP_READ(vp, ap->a_uio, 0, ap->a_cred));
}

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

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

/*
 * Unlock an inode.  If WANT bit is on, wakeup.
 */
int
ufs_unlock(v)
      void *v;
{
      struct vop_unlock_args /* {
            struct vnode *a_vp;
            int a_flags;
            struct proc *a_p;
      } */ *ap = v;
      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(v)
      void *v;
{
      struct vop_islocked_args /* {
            struct vnode *a_vp;
      } */ *ap = v;

      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(v)
      void *v;
{
      struct vop_strategy_args /* {
            struct buf *a_bp;
      } */ *ap = v;
      struct buf *bp = ap->a_bp;
      struct vnode *vp = bp->b_vp;
      struct inode *ip;
      int error;
      int s;

      ip = VTOI(vp);
      if (vp->v_type == VBLK || vp->v_type == VCHR)
            panic("ufs_strategy: spec");
      if (bp->b_blkno == bp->b_lblkno) {
            error = VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno,
                         NULL);
            if (error) {
                  bp->b_error = error;
                  bp->b_flags |= B_ERROR;
                  s = splbio();
                  biodone(bp);
                  splx(s);
                  return (error);
            }
            if ((long)bp->b_blkno == -1)
                  clrbuf(bp);
      }
      if ((long)bp->b_blkno == -1) {
            s = splbio();
            biodone(bp);
            splx(s);
            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(v)
      void *v;
{
      struct vop_print_args /* {
            struct vnode *a_vp;
      } */ *ap = v;
      struct vnode *vp = ap->a_vp;
      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));
      printf(" flags 0x%x, effnlink %d, nlink %d\n",
             ip->i_flag, ip->i_effnlink, ip->i_ffs_nlink);
      printf("\tmode 0%o, owner %d, group %d, size %lld",
             ip->i_ffs_mode, ip->i_ffs_uid, ip->i_ffs_gid, ip->i_ffs_size);

#ifdef 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(v)
      void *v;
{
      struct vop_read_args /* {
            struct vnode *a_vp;
            struct uio *a_uio;
            int  a_ioflag;
            struct ucred *a_cred;
      } */ *ap = v;

      /*
       * 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(v)
      void *v;
{
      struct vop_write_args /* {
            struct vnode *a_vp;
            struct uio *a_uio;
            int  a_ioflag;
            struct ucred *a_cred;
      } */ *ap = v;

      /*
       * 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(v)
      void *v;
{
      struct vop_close_args /* {
            struct vnode *a_vp;
            int  a_fflag;
            struct ucred *a_cred;
            struct proc *a_p;
      } */ *ap = v;
      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));
}

#ifdef FIFO
/*
 * Read wrapper for fifo's
 */
int
ufsfifo_read(v)
      void *v;
{
      struct vop_read_args /* {
            struct vnode *a_vp;
            struct uio *a_uio;
            int  a_ioflag;
            struct ucred *a_cred;
      } */ *ap = v;
      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(v)
      void *v;
{
      struct vop_write_args /* {
            struct vnode *a_vp;
            struct uio *a_uio;
            int  a_ioflag;
            struct ucred *a_cred;
      } */ *ap = v;
      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.
 */
int
ufsfifo_close(v)
      void *v;
{
      struct vop_close_args /* {
            struct vnode *a_vp;
            int  a_fflag;
            struct ucred *a_cred;
            struct proc *a_p;
      } */ *ap = v;
      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.
 */
int
ufs_pathconf(v)
      void *v;
{
      struct vop_pathconf_args /* {
            struct vnode *a_vp;
            int a_name;
            register_t *a_retval;
      } */ *ap = v;

      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(v)
      void *v;
{
      struct vop_advlock_args /* {
            struct vnode *a_vp;
            caddr_t  a_id;
            int  a_op;
            struct flock *a_fl;
            int  a_flags;
      } */ *ap = v;
      struct inode *ip = VTOI(ap->a_vp);

      return (lf_advlock(&ip->i_lockf, ip->i_ffs_size, ap->a_id, ap->a_op,
          ap->a_fl, ap->a_flags));
}

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

      vp = *vpp;
      ip = VTOI(vp);
      switch(vp->v_type = IFTOVT(ip->i_ffs_mode)) {
      case VCHR:
      case VBLK:
            vp->v_op = specops;
            if ((nvp = checkalias(vp, ip->i_ffs_rdev, mntp)) != NULL) {
                  /*
                   * 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;
#ifdef VFSDEBUG
                  vp->v_flag &= ~VLOCKSWORK;
#endif
                  vrele(vp);
                  vgone(vp);
                  /*
                   * Reinitialize aliased inode.
                   */
                  vp = nvp;
                  ip->i_vnode = vp;
            }
            break;
      case VFIFO:
#ifdef FIFO
            vp->v_op = fifoops;
            break;
#else
            return (EOPNOTSUPP);
#endif
      case VNON:
      case VBAD:
      case VSOCK:
      case VLNK:
      case VDIR:
      case VREG:
            break;
      }
      if (ip->i_number == ROOTINO)
                vp->v_flag |= VROOT;
      /*
       * Initialize modrev times
       */
      SETHIGH(ip->i_modrev, mono_time.tv_sec);
      SETLOW(ip->i_modrev, mono_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;
{
      struct inode *ip, *pdir;
      struct direct newdir;
      struct vnode *tvp;
      int error;

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

      if ((error = UFS_INODE_ALLOC(pdir, mode, cnp->cn_cred, &tvp)) != 0) {
            pool_put(&namei_pool, cnp->cn_pnbuf);
            vput(dvp);
            return (error);
      }
      ip = VTOI(tvp);
      ip->i_ffs_gid = pdir->i_ffs_gid;
      ip->i_ffs_uid = cnp->cn_cred->cr_uid;

      if ((error = getinoquota(ip)) ||
          (error = ufs_quota_alloc_inode(ip, cnp->cn_cred))) {
            pool_put(&namei_pool, cnp->cn_pnbuf);
            UFS_INODE_FREE(ip, ip->i_number, mode);
            vput(tvp);
            vput(dvp);
            return (error);
      }

      ip->i_flag |= IN_ACCESS | IN_CHANGE | IN_UPDATE;
      ip->i_ffs_mode = mode;
      tvp->v_type = IFTOVT(mode);   /* Rest init'd in getnewvnode(). */
      ip->i_effnlink = 1;
      ip->i_ffs_nlink = 1;
      if (DOINGSOFTDEP(tvp))
            softdep_change_linkcnt(ip, 0);
      if ((ip->i_ffs_mode & ISGID) &&
            !groupmember(ip->i_ffs_gid, cnp->cn_cred) &&
          suser_ucred(cnp->cn_cred))
            ip->i_ffs_mode &= ~ISGID;

      /*
       * Make sure inode goes to disk before directory entry.
       */
      if ((error = UFS_UPDATE(ip, !DOINGSOFTDEP(tvp))) != 0)
            goto bad;

      ufs_makedirentry(ip, cnp, &newdir);
      if ((error = ufs_direnter(dvp, tvp, &newdir, cnp, NULL)) != 0)
            goto bad;

      if ((cnp->cn_flags & SAVESTART) == 0)
            pool_put(&namei_pool, cnp->cn_pnbuf);
      vput(dvp);
      *vpp = tvp;
      return (0);

bad:
      /*
       * Write error occurred trying to update the inode
       * or the directory so must deallocate the inode.
       */
      pool_put(&namei_pool, cnp->cn_pnbuf);
      vput(dvp);
      ip->i_effnlink = 0;
      ip->i_ffs_nlink = 0;
      ip->i_flag |= IN_CHANGE;
      if (DOINGSOFTDEP(tvp))
            softdep_change_linkcnt(ip, 0);
      tvp->v_type = VNON;
      vput(tvp);

      return (error);
}

struct filterops ufsread_filtops = 
      { 1, NULL, filt_ufsdetach, filt_ufsread };
struct filterops ufswrite_filtops = 
      { 1, NULL, filt_ufsdetach, filt_ufswrite };
struct filterops ufsvnode_filtops = 
      { 1, NULL, filt_ufsdetach, filt_ufsvnode };

int
ufs_kqfilter(v)
      void *v;
{
      struct vop_kqfilter_args /* {
            struct vnode *a_vp;
            struct knote *a_kn;
      } */ *ap = v;
      struct vnode *vp = ap->a_vp;
      struct knote *kn = ap->a_kn;

      switch (kn->kn_filter) {
      case EVFILT_READ:
            kn->kn_fop = &ufsread_filtops;
            break;
      case EVFILT_WRITE:
            kn->kn_fop = &ufswrite_filtops;
            break;
      case EVFILT_VNODE:
            kn->kn_fop = &ufsvnode_filtops;
            break;
      default:
            return (1);
      }

      kn->kn_hook = (caddr_t)vp;

      simple_lock(&vp->v_selectinfo.vsi_lock);
      SLIST_INSERT_HEAD(&vp->v_selectinfo.vsi_selinfo.si_note, kn, kn_selnext);
      simple_unlock(&vp->v_selectinfo.vsi_lock);

      return (0);
}

void
filt_ufsdetach(struct knote *kn)
{
      struct vnode *vp = (struct vnode *)kn->kn_hook;

      simple_lock(&vp->v_selectinfo.vsi_lock);
      SLIST_REMOVE(&vp->v_selectinfo.vsi_selinfo.si_note,
          kn, knote, kn_selnext);
      simple_unlock(&vp->v_selectinfo.vsi_lock);
}

/*ARGSUSED*/
int
filt_ufsread(struct knote *kn, long hint)
{
      struct vnode *vp = (struct vnode *)kn->kn_hook;
      struct inode *ip = VTOI(vp);

      /*
       * filesystem is gone, so set the EOF flag and schedule 
       * the knote for deletion.
       */
      if (hint == NOTE_REVOKE) {
            kn->kn_flags |= (EV_EOF | EV_ONESHOT);
            return (1);
      }

        kn->kn_data = ip->i_ffs_size - kn->kn_fp->f_offset;
      if (kn->kn_data == 0 && kn->kn_sfflags & NOTE_EOF) {
            kn->kn_fflags |= NOTE_EOF;
            return (1);
      }

        return (kn->kn_data != 0);
}

int
filt_ufswrite(struct knote *kn, long hint)
{
      /*
       * filesystem is gone, so set the EOF flag and schedule 
       * the knote for deletion.
       */
      if (hint == NOTE_REVOKE) {
            kn->kn_flags |= (EV_EOF | EV_ONESHOT);
            return (1);
      }

        kn->kn_data = 0;
        return (1);
}

int
filt_ufsvnode(struct knote *kn, long hint)
{
      if (kn->kn_sfflags & hint)
            kn->kn_fflags |= hint;
      if (hint == NOTE_REVOKE) {
            kn->kn_flags |= EV_EOF;
            return (1);
      }
      return (kn->kn_fflags != 0);
}

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