MFV ntp 4.2.8p1 (r258945, r275970, r276091, r276092, r276093, r278284)

[FreeBSD/FreeBSD.git] / sys / fs / ext2fs / ext2_vnops.c

/*-
 *  modified for EXT2FS support in Lites 1.1
 *
 *  Aug 1995, Godmar Back (gback@cs.utah.edu)
 *  University of Utah, Department of Computer Science
 */
/*-
 * 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.
 * 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 8.7 (Berkeley) 2/3/94
 *      @(#)ufs_vnops.c 8.27 (Berkeley) 5/27/95
 * $FreeBSD$
 */

#include "opt_suiddir.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/fcntl.h>
#include <sys/filio.h>
#include <sys/stat.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/endian.h>
#include <sys/priv.h>
#include <sys/rwlock.h>
#include <sys/mount.h>
#include <sys/unistd.h>
#include <sys/time.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/lockf.h>
#include <sys/event.h>
#include <sys/conf.h>
#include <sys/file.h>

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

#include "opt_directio.h"

#include <ufs/ufs/dir.h>

#include <fs/ext2fs/fs.h>
#include <fs/ext2fs/inode.h>
#include <fs/ext2fs/ext2_extern.h>
#include <fs/ext2fs/ext2fs.h>
#include <fs/ext2fs/ext2_dinode.h>
#include <fs/ext2fs/ext2_dir.h>
#include <fs/ext2fs/ext2_mount.h>

static int ext2_makeinode(int mode, struct vnode *, struct vnode **, struct componentname *);
static void ext2_itimes_locked(struct vnode *);
static int ext4_ext_read(struct vop_read_args *);
static int ext2_ind_read(struct vop_read_args *);

static vop_access_t     ext2_access;
static int ext2_chmod(struct vnode *, int, struct ucred *, struct thread *);
static int ext2_chown(struct vnode *, uid_t, gid_t, struct ucred *,
    struct thread *);
static vop_close_t      ext2_close;
static vop_create_t     ext2_create;
static vop_fsync_t      ext2_fsync;
static vop_getattr_t    ext2_getattr;
static vop_ioctl_t      ext2_ioctl;
static vop_link_t       ext2_link;
static vop_mkdir_t      ext2_mkdir;
static vop_mknod_t      ext2_mknod;
static vop_open_t       ext2_open;
static vop_pathconf_t   ext2_pathconf;
static vop_print_t      ext2_print;
static vop_read_t       ext2_read;
static vop_readlink_t   ext2_readlink;
static vop_remove_t     ext2_remove;
static vop_rename_t     ext2_rename;
static vop_rmdir_t      ext2_rmdir;
static vop_setattr_t    ext2_setattr;
static vop_strategy_t   ext2_strategy;
static vop_symlink_t    ext2_symlink;
static vop_write_t      ext2_write;
static vop_vptofh_t     ext2_vptofh;
static vop_close_t      ext2fifo_close;
static vop_kqfilter_t   ext2fifo_kqfilter;

/* Global vfs data structures for ext2. */
struct vop_vector ext2_vnodeops = {
        .vop_default =          &default_vnodeops,
        .vop_access =           ext2_access,
        .vop_bmap =             ext2_bmap,
        .vop_cachedlookup =     ext2_lookup,
        .vop_close =            ext2_close,
        .vop_create =           ext2_create,
        .vop_fsync =            ext2_fsync,
        .vop_getpages =         vnode_pager_local_getpages,
        .vop_getattr =          ext2_getattr,
        .vop_inactive =         ext2_inactive,
        .vop_ioctl =            ext2_ioctl,
        .vop_link =             ext2_link,
        .vop_lookup =           vfs_cache_lookup,
        .vop_mkdir =            ext2_mkdir,
        .vop_mknod =            ext2_mknod,
        .vop_open =             ext2_open,
        .vop_pathconf =         ext2_pathconf,
        .vop_poll =             vop_stdpoll,
        .vop_print =            ext2_print,
        .vop_read =             ext2_read,
        .vop_readdir =          ext2_readdir,
        .vop_readlink =         ext2_readlink,
        .vop_reallocblks =      ext2_reallocblks,
        .vop_reclaim =          ext2_reclaim,
        .vop_remove =           ext2_remove,
        .vop_rename =           ext2_rename,
        .vop_rmdir =            ext2_rmdir,
        .vop_setattr =          ext2_setattr,
        .vop_strategy =         ext2_strategy,
        .vop_symlink =          ext2_symlink,
        .vop_write =            ext2_write,
        .vop_vptofh =           ext2_vptofh,
};

struct vop_vector ext2_fifoops = {
        .vop_default =          &fifo_specops,
        .vop_access =           ext2_access,
        .vop_close =            ext2fifo_close,
        .vop_fsync =            ext2_fsync,
        .vop_getattr =          ext2_getattr,
        .vop_inactive =         ext2_inactive,
        .vop_kqfilter =         ext2fifo_kqfilter,
        .vop_print =            ext2_print,
        .vop_read =             VOP_PANIC,
        .vop_reclaim =          ext2_reclaim,
        .vop_setattr =          ext2_setattr,
        .vop_write =            VOP_PANIC,
        .vop_vptofh =           ext2_vptofh,
};

/*
 * A virgin directory (no blushing please).
 * Note that the type and namlen fields are reversed relative to ext2.
 * Also, we don't use `struct odirtemplate', since it would just cause
 * endianness problems.
 */
static struct dirtemplate mastertemplate = {
        0, 12, 1, EXT2_FT_DIR, ".",
        0, DIRBLKSIZ - 12, 2, EXT2_FT_DIR, ".."
};
static struct dirtemplate omastertemplate = {
        0, 12, 1, EXT2_FT_UNKNOWN, ".",
        0, DIRBLKSIZ - 12, 2, EXT2_FT_UNKNOWN, ".."
};

static void
ext2_itimes_locked(struct vnode *vp)
{
        struct inode *ip;
        struct timespec ts;

        ASSERT_VI_LOCKED(vp, __func__); 

        ip = VTOI(vp);
        if ((ip->i_flag & (IN_ACCESS | IN_CHANGE | IN_UPDATE)) == 0)
                return;
        if ((vp->v_type == VBLK || vp->v_type == VCHR))
                ip->i_flag |= IN_LAZYMOD;
        else
                ip->i_flag |= IN_MODIFIED;
        if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
                vfs_timestamp(&ts);
                if (ip->i_flag & IN_ACCESS) {
                        ip->i_atime = ts.tv_sec;
                        ip->i_atimensec = ts.tv_nsec;
                }
                if (ip->i_flag & IN_UPDATE) {
                        ip->i_mtime = ts.tv_sec;
                        ip->i_mtimensec = ts.tv_nsec;
                        ip->i_modrev++;
                }
                if (ip->i_flag & IN_CHANGE) {
                        ip->i_ctime = ts.tv_sec;
                        ip->i_ctimensec = ts.tv_nsec;
                }
        }
        ip->i_flag &= ~(IN_ACCESS | IN_CHANGE | IN_UPDATE);
}

void
ext2_itimes(struct vnode *vp)
{

        VI_LOCK(vp);
        ext2_itimes_locked(vp);
        VI_UNLOCK(vp);
}

/*
 * Create a regular file
 */
static int
ext2_create(struct vop_create_args *ap)
{
        int error;

        error =
            ext2_makeinode(MAKEIMODE(ap->a_vap->va_type, ap->a_vap->va_mode),
            ap->a_dvp, ap->a_vpp, ap->a_cnp);
        if (error != 0)
                return (error);
        if ((ap->a_cnp->cn_flags & MAKEENTRY) != 0)
                cache_enter(ap->a_dvp, *ap->a_vpp, ap->a_cnp);
        return (0);
}

static int
ext2_open(struct vop_open_args *ap)
{

        if (ap->a_vp->v_type == VBLK || ap->a_vp->v_type == VCHR)
                return (EOPNOTSUPP);

        /*
         * 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);

        vnode_create_vobject(ap->a_vp, VTOI(ap->a_vp)->i_size, ap->a_td);

        return (0);
}

/*
 * Close called.
 *
 * Update the times on the inode.
 */
static int
ext2_close(struct vop_close_args *ap)
{
        struct vnode *vp = ap->a_vp;

        VI_LOCK(vp);
        if (vp->v_usecount > 1)
                ext2_itimes_locked(vp);
        VI_UNLOCK(vp);
        return (0);
}

static int
ext2_access(struct vop_access_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct inode *ip = VTOI(vp);
        accmode_t accmode = ap->a_accmode;
        int error;

        if (vp->v_type == VBLK || vp->v_type == VCHR)
                return (EOPNOTSUPP);

        /*
         * 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 (accmode & VWRITE) {
                switch (vp->v_type) {
                case VDIR:
                case VLNK:
                case VREG:
                        if (vp->v_mount->mnt_flag & MNT_RDONLY)
                                return (EROFS);
                        break;
                default:
                        break;
                }
        }

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

        error = vaccess(vp->v_type, ip->i_mode, ip->i_uid, ip->i_gid,
            ap->a_accmode, ap->a_cred, NULL);
        return (error);
}

static int
ext2_getattr(struct vop_getattr_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct inode *ip = VTOI(vp);
        struct vattr *vap = ap->a_vap;

        ext2_itimes(vp);
        /*
         * Copy from inode table
         */
        vap->va_fsid = dev2udev(ip->i_devvp->v_rdev);
        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 = ip->i_rdev;
        vap->va_size = ip->i_size;
        vap->va_atime.tv_sec = ip->i_atime;
        vap->va_atime.tv_nsec = E2DI_HAS_XTIME(ip) ? ip->i_atimensec : 0;
        vap->va_mtime.tv_sec = ip->i_mtime;
        vap->va_mtime.tv_nsec = E2DI_HAS_XTIME(ip) ? ip->i_mtimensec : 0;
        vap->va_ctime.tv_sec = ip->i_ctime;
        vap->va_ctime.tv_nsec = E2DI_HAS_XTIME(ip) ? ip->i_ctimensec : 0;
        if E2DI_HAS_XTIME(ip) {
                vap->va_birthtime.tv_sec = ip->i_birthtime;
                vap->va_birthtime.tv_nsec = ip->i_birthnsec;
        }
        vap->va_flags = ip->i_flags;
        vap->va_gen = ip->i_gen;
        vap->va_blocksize = vp->v_mount->mnt_stat.f_iosize;
        vap->va_bytes = dbtob((u_quad_t)ip->i_blocks);
        vap->va_type = IFTOVT(ip->i_mode);
        vap->va_filerev = ip->i_modrev;
        return (0);
}

/*
 * Set attribute vnode op. called from several syscalls
 */
static int
ext2_setattr(struct vop_setattr_args *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 thread *td = curthread;
        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) {
                /* Disallow flags not supported by ext2fs. */
                if(vap->va_flags & ~(SF_APPEND | SF_IMMUTABLE | UF_NODUMP))
                        return (EOPNOTSUPP);

                if (vp->v_mount->mnt_flag & MNT_RDONLY)
                        return (EROFS);
                /*
                 * Callers may only modify the file flags on objects they
                 * have VADMIN rights for.
                 */
                if ((error = VOP_ACCESS(vp, VADMIN, cred, td)))
                        return (error);
                /*
                 * Unprivileged processes and privileged processes in
                 * jail() are not permitted to unset system flags, or
                 * modify flags if any system flags are set.
                 * Privileged non-jail processes may not modify system flags
                 * if securelevel > 0 and any existing system flags are set.
                 */
                if (!priv_check_cred(cred, PRIV_VFS_SYSFLAGS, 0)) {
                        if (ip->i_flags & (SF_IMMUTABLE | SF_APPEND)) {
                                error = securelevel_gt(cred, 0);
                                if (error)
                                        return (error);
                        }
                } else {
                        if (ip->i_flags & (SF_IMMUTABLE | SF_APPEND) ||
                            ((vap->va_flags ^ ip->i_flags) & SF_SETTABLE))
                                return (EPERM);
                }
                ip->i_flags = vap->va_flags;
                ip->i_flag |= IN_CHANGE;
                if (ip->i_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 = ext2_chown(vp, vap->va_uid, vap->va_gid, cred,
                    td)) != 0)
                        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;
                default:
                        break;
                }
                if ((error = ext2_truncate(vp, vap->va_size, 0, cred, td)) != 0)
                        return (error);
        }
        if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
                if (vp->v_mount->mnt_flag & MNT_RDONLY)
                        return (EROFS);
                /*
                 * From utimes(2):
                 * If times is NULL, ... The caller must be the owner of
                 * the file, have permission to write the file, or be the
                 * super-user.
                 * If times is non-NULL, ... The caller must be the owner of
                 * the file or be the super-user.
                 */
                if ((error = VOP_ACCESS(vp, VADMIN, cred, td)) &&
                    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
                    (error = VOP_ACCESS(vp, VWRITE, cred, td))))
                        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;
                ext2_itimes(vp);
                if (vap->va_atime.tv_sec != VNOVAL) {
                        ip->i_atime = vap->va_atime.tv_sec;
                        ip->i_atimensec = vap->va_atime.tv_nsec;
                }
                if (vap->va_mtime.tv_sec != VNOVAL) {
                        ip->i_mtime = vap->va_mtime.tv_sec;
                        ip->i_mtimensec = vap->va_mtime.tv_nsec;
                }
                ip->i_birthtime = vap->va_birthtime.tv_sec;
                ip->i_birthnsec = vap->va_birthtime.tv_nsec;
                error = ext2_update(vp, 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 = ext2_chmod(vp, (int)vap->va_mode, cred, td);
        }
        return (error);
}

/*
 * Change the mode on a file.
 * Inode must be locked before calling.
 */
static int
ext2_chmod(struct vnode *vp, int mode, struct ucred *cred, struct thread *td)
{
        struct inode *ip = VTOI(vp);
        int error;

        /*
         * To modify the permissions on a file, must possess VADMIN
         * for that file.
         */
        if ((error = VOP_ACCESS(vp, VADMIN, cred, td)))
                return (error);
        /*
         * Privileged processes may set the sticky bit on non-directories,
         * as well as set the setgid bit on a file with a group that the
         * process is not a member of.
         */
        if (vp->v_type != VDIR && (mode & S_ISTXT)) {
                error = priv_check_cred(cred, PRIV_VFS_STICKYFILE, 0);
                if (error)
                        return (EFTYPE);
        }
        if (!groupmember(ip->i_gid, cred) && (mode & ISGID)) {
                error = priv_check_cred(cred, PRIV_VFS_SETGID, 0);
                if (error)
                        return (error);
        }
        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
ext2_chown(struct vnode *vp, uid_t uid, gid_t gid, struct ucred *cred,
    struct thread *td)
{
        struct inode *ip = VTOI(vp);
        uid_t ouid;
        gid_t ogid;
        int error = 0;

        if (uid == (uid_t)VNOVAL)
                uid = ip->i_uid;
        if (gid == (gid_t)VNOVAL)
                gid = ip->i_gid;
        /*
         * To modify the ownership of a file, must possess VADMIN
         * for that file.
         */
        if ((error = VOP_ACCESS(vp, VADMIN, cred, td)))
                return (error);
        /*
         * To change the owner of a file, or change the group of a file
         * to a group of which we are not a member, the caller must
         * have privilege.
         */
        if (uid != ip->i_uid || (gid != ip->i_gid &&
            !groupmember(gid, cred))) {
                error = priv_check_cred(cred, PRIV_VFS_CHOWN, 0);
                if (error)
                        return (error);
        }
        ogid = ip->i_gid;
        ouid = ip->i_uid;
        ip->i_gid = gid;
        ip->i_uid = uid;
        ip->i_flag |= IN_CHANGE;
        if ((ip->i_mode & (ISUID | ISGID)) && (ouid != uid || ogid != gid)) {
                if (priv_check_cred(cred, PRIV_VFS_RETAINSUGID, 0) != 0)
                        ip->i_mode &= ~(ISUID | ISGID);
        }
        return (0);
}

/*
 * Synch an open file.
 */
/* ARGSUSED */
static int
ext2_fsync(struct vop_fsync_args *ap)
{
        /*
         * Flush all dirty buffers associated with a vnode.
         */

        vop_stdfsync(ap);

        return (ext2_update(ap->a_vp, ap->a_waitfor == MNT_WAIT));
}

/*
 * Mknod vnode call
 */
/* ARGSUSED */
static int
ext2_mknod(struct vop_mknod_args *ap)
{
        struct vattr *vap = ap->a_vap;
        struct vnode **vpp = ap->a_vpp;
        struct inode *ip;
        ino_t ino;
        int error;

        error = ext2_makeinode(MAKEIMODE(vap->va_type, vap->va_mode),
            ap->a_dvp, vpp, ap->a_cnp);
        if (error)
                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, then reload it through VFS_VGET so it is
         * checked to see if it is an alias of an existing entry in
         * the inode cache.      XXX I don't believe this is necessary now.
         */
        (*vpp)->v_type = VNON;
        ino = ip->i_number;     /* Save this before vgone() invalidates ip. */
        vgone(*vpp);
        vput(*vpp);
        error = VFS_VGET(ap->a_dvp->v_mount, ino, LK_EXCLUSIVE, vpp);
        if (error) {
                *vpp = NULL;
                return (error);
        }
        return (0);
}

static int
ext2_remove(struct vop_remove_args *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 & (NOUNLINK | IMMUTABLE | APPEND)) ||
            (VTOI(dvp)->i_flags & APPEND)) {
                error = EPERM;
                goto out;
        }
        error = ext2_dirremove(dvp, ap->a_cnp);
        if (error == 0) {
                ip->i_nlink--;
                ip->i_flag |= IN_CHANGE;
        }
out:
        return (error);
}

/*
 * link vnode call
 */
static int
ext2_link(struct vop_link_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct vnode *tdvp = ap->a_tdvp;
        struct componentname *cnp = ap->a_cnp;
        struct inode *ip;
        int error;

#ifdef INVARIANTS
        if ((cnp->cn_flags & HASBUF) == 0)
                panic("ext2_link: no name");
#endif
        ip = VTOI(vp);
        if ((nlink_t)ip->i_nlink >= EXT2_LINK_MAX) {
                error = EMLINK;
                goto out;
        }
        if (ip->i_flags & (IMMUTABLE | APPEND)) {
                error = EPERM;
                goto out;
        }
        ip->i_nlink++;
        ip->i_flag |= IN_CHANGE;
        error = ext2_update(vp, !DOINGASYNC(vp));
        if (!error)
                error = ext2_direnter(ip, tdvp, cnp);
        if (error) {
                ip->i_nlink--;
                ip->i_flag |= IN_CHANGE;
        }
out:
        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.
 */
static int
ext2_rename(struct vop_rename_args *ap)
{
        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 inode *ip, *xp, *dp;
        struct dirtemplate dirbuf;
        int doingdirectory = 0, oldparent = 0, newparent = 0;
        int error = 0;
        u_char namlen;

#ifdef INVARIANTS
        if ((tcnp->cn_flags & HASBUF) == 0 ||
            (fcnp->cn_flags & HASBUF) == 0)
                panic("ext2_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:
                if (tdvp == tvp)
                        vrele(tdvp);
                else
                        vput(tdvp);
                if (tvp)
                        vput(tvp);
                vrele(fdvp);
                vrele(fvp);
                return (error);
        }

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

        /*
         * Renaming a file to itself has no effect.  The upper layers should
         * not call us in that case.  Temporarily just warn if they do.
         */
        if (fvp == tvp) {
                printf("ext2_rename: fvp == tvp (can't happen)\n");
                error = 0;
                goto abortit;
        }

        if ((error = vn_lock(fvp, LK_EXCLUSIVE)) != 0)
                goto abortit;
        dp = VTOI(fdvp);
        ip = VTOI(fvp);
        if (ip->i_nlink >= EXT2_LINK_MAX) {
                VOP_UNLOCK(fvp, 0);
                error = EMLINK;
                goto abortit;
        }
        if ((ip->i_flags & (NOUNLINK | IMMUTABLE | APPEND))
            || (dp->i_flags & APPEND)) {
                VOP_UNLOCK(fvp, 0);
                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 | tcnp->cn_flags) & ISDOTDOT ||
                    (ip->i_flag & IN_RENAME)) {
                        VOP_UNLOCK(fvp, 0);
                        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;
        if ((error = ext2_update(fvp, !DOINGASYNC(fvp))) != 0) {
                VOP_UNLOCK(fvp, 0);
                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_thread);
        VOP_UNLOCK(fvp, 0);
        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);
                error = ext2_checkpath(ip, dp, tcnp->cn_cred);
                if (error)
                        goto out;
                VREF(tdvp);
                error = relookup(tdvp, &tvp, tcnp);
                if (error)
                        goto out;
                vrele(tdvp);
                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_devvp != ip->i_devvp)
                        panic("ext2_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 >= EXT2_LINK_MAX) {
                                error = EMLINK;
                                goto bad;
                        }
                        dp->i_nlink++;
                        dp->i_flag |= IN_CHANGE;
                        error = ext2_update(tdvp, !DOINGASYNC(tdvp));
                        if (error)
                                goto bad;
                }
                error = ext2_direnter(ip, tdvp, tcnp);
                if (error) {
                        if (doingdirectory && newparent) {
                                dp->i_nlink--;
                                dp->i_flag |= IN_CHANGE;
                                (void)ext2_update(tdvp, 1);
                        }
                        goto bad;
                }
                vput(tdvp);
        } else {
                if (xp->i_devvp != dp->i_devvp || xp->i_devvp != ip->i_devvp)
                       panic("ext2_rename: EXDEV");
                /*
                 * Short circuit rename(foo, foo).
                 */
                if (xp->i_number == ip->i_number)
                        panic("ext2_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 (! ext2_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;
                }
                error = ext2_dirrewrite(dp, ip, tcnp);
                if (error)
                        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("ext2_rename: linked directory");
                        error = ext2_truncate(tvp, (off_t)0, IO_SYNC,
                            tcnp->cn_cred, tcnp->cn_thread);
                }
                xp->i_flag |= IN_CHANGE;
                vput(tvp);
                xp = NULL;
        }

        /*
         * 3) Unlink the source.
         */
        fcnp->cn_flags &= ~MODMASK;
        fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
        VREF(fdvp);
        error = relookup(fdvp, &fvp, fcnp);
        if (error == 0)
                vrele(fdvp);
        if (fvp != NULL) {
                xp = VTOI(fvp);
                dp = VTOI(fdvp);
        } else {
                /*
                 * From name has disappeared.
                 */
                if (doingdirectory)
                        panic("ext2_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 IN_RENAME flag ensures that it cannot be moved by another
         * rename.
         */
        if (xp != ip) {
                if (doingdirectory)
                        panic("ext2_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 | IO_NOMACCHECK,
                                tcnp->cn_cred, NOCRED, NULL, NULL);
                        if (error == 0) {
                                /* Like ufs little-endian: */
                                namlen = dirbuf.dotdot_type;
                                if (namlen != 2 ||
                                    dirbuf.dotdot_name[0] != '.' ||
                                    dirbuf.dotdot_name[1] != '.') {
                                        ext2_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 |
                                            IO_NOMACCHECK, tcnp->cn_cred,
                                            NOCRED, NULL, NULL);
                                        cache_purge(fdvp);
                                }
                        }
                }
                error = ext2_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) == 0) {
                ip->i_nlink--;
                ip->i_flag |= IN_CHANGE;
                ip->i_flag &= ~IN_RENAME;
                vput(fvp);
        } else
                vrele(fvp);
        return (error);
}

/*
 * Mkdir system call
 */
static int
ext2_mkdir(struct vop_mkdir_args *ap)
{
        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 dirtemplate dirtemplate, *dtp;
        int error, dmode;

#ifdef INVARIANTS
        if ((cnp->cn_flags & HASBUF) == 0)
                panic("ext2_mkdir: no name");
#endif
        dp = VTOI(dvp);
        if ((nlink_t)dp->i_nlink >= EXT2_LINK_MAX) {
                error = EMLINK;
                goto out;
        }
        dmode = vap->va_mode & 0777;
        dmode |= IFDIR;
        /*
         * Must simulate part of ext2_makeinode here to acquire the inode,
         * but not have it entered in the parent directory. The entry is
         * made later after writing "." and ".." entries.
         */
        error = ext2_valloc(dvp, dmode, cnp->cn_cred, &tvp);
        if (error)
                goto out;
        ip = VTOI(tvp);
        ip->i_gid = dp->i_gid;
#ifdef SUIDDIR
        {
                /*
                 * if we are hacking owners here, (only do this where told to)
                 * and we are not giving it TOO root, (would subvert quotas)
                 * then go ahead and give it to the other user.
                 * The new directory also inherits the SUID bit. 
                 * If user's UID and dir UID are the same,
                 * 'give it away' so that the SUID is still forced on.
                 */
                if ( (dvp->v_mount->mnt_flag & MNT_SUIDDIR) &&
                   (dp->i_mode & ISUID) && dp->i_uid) {
                        dmode |= ISUID;
                        ip->i_uid = dp->i_uid;
                } else {
                        ip->i_uid = cnp->cn_cred->cr_uid;
                }
        }
#else
        ip->i_uid = cnp->cn_cred->cr_uid;
#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;
        error = ext2_update(tvp, 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;
        error = ext2_update(dvp, !DOINGASYNC(dvp));
        if (error)
                goto bad;

        /* Initialize directory with "." and ".." from static template. */
        if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
            EXT2F_INCOMPAT_FTYPE))
                dtp = &mastertemplate;
        else
                dtp = &omastertemplate;
        dirtemplate = *dtp;
        dirtemplate.dot_ino = ip->i_number;
        dirtemplate.dotdot_ino = dp->i_number;
        /* note that in ext2 DIRBLKSIZ == blocksize, not DEV_BSIZE 
         * so let's just redefine it - for this function only
         */
#undef  DIRBLKSIZ 
#define DIRBLKSIZ  VTOI(dvp)->i_e2fs->e2fs_bsize
        dirtemplate.dotdot_reclen = DIRBLKSIZ - 12;
        error = vn_rdwr(UIO_WRITE, tvp, (caddr_t)&dirtemplate,
            sizeof(dirtemplate), (off_t)0, UIO_SYSSPACE,
            IO_NODELOCKED | IO_SYNC | IO_NOMACCHECK, cnp->cn_cred, NOCRED,
            NULL, NULL);
        if (error) {
                dp->i_nlink--;
                dp->i_flag |= IN_CHANGE;
                goto bad;
        }
        if (DIRBLKSIZ > VFSTOEXT2(dvp->v_mount)->um_mountp->mnt_stat.f_bsize)
                /* XXX should grow with balloc() */
                panic("ext2_mkdir: blksize");
        else {
                ip->i_size = DIRBLKSIZ;
                ip->i_flag |= IN_CHANGE;
        }

        /* Directory set up, now install its entry in the parent directory. */
        error = ext2_direnter(ip, dvp, cnp);
        if (error) {
                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:
        return (error);
#undef  DIRBLKSIZ
#define DIRBLKSIZ  DEV_BSIZE
}

/*
 * Rmdir system call.
 */
static int
ext2_rmdir(struct vop_rmdir_args *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);

        /*
         * 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.)
         */
        if (ip->i_nlink != 2 || !ext2_dirempty(ip, dp->i_number, cnp->cn_cred)) {
                error = ENOTEMPTY;
                goto out;
        }
        if ((dp->i_flags & APPEND)
            || (ip->i_flags & (NOUNLINK | 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,
         */
        error = ext2_dirremove(dvp, cnp);
        if (error)
                goto out;
        dp->i_nlink--;
        dp->i_flag |= IN_CHANGE;
        cache_purge(dvp);
        VOP_UNLOCK(dvp, 0);
        /*
         * 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 = ext2_truncate(vp, (off_t)0, IO_SYNC, cnp->cn_cred,
            cnp->cn_thread);
        cache_purge(ITOV(ip));
        if (vn_lock(dvp, LK_EXCLUSIVE | LK_NOWAIT) != 0) {
                VOP_UNLOCK(vp, 0);
                vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
                vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        }
out:
        return (error);
}

/*
 * symlink -- make a symbolic link
 */
static int
ext2_symlink(struct vop_symlink_args *ap)
{
        struct vnode *vp, **vpp = ap->a_vpp;
        struct inode *ip;
        int len, error;

        error = ext2_makeinode(IFLNK | ap->a_vap->va_mode, ap->a_dvp,
            vpp, ap->a_cnp);
        if (error)
                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 | IO_NOMACCHECK,
                    ap->a_cnp->cn_cred, NOCRED, NULL, NULL);
        if (error)
                vput(vp);
        return (error);
}

/*
 * Return target name of a symbolic link
 */
static int
ext2_readlink(struct vop_readlink_args *ap)
{
        struct vnode *vp = ap->a_vp;
        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));
}

/*
 * Calculate the logical to physical mapping if not done already,
 * then call the device strategy routine.
 *
 * In order to be able to swap to a file, the ext2_bmaparray() operation may not
 * deadlock on memory.  See ext2_bmap() for details.
 */
static int
ext2_strategy(struct vop_strategy_args *ap)
{
        struct buf *bp = ap->a_bp;
        struct vnode *vp = ap->a_vp;
        struct bufobj *bo;
        daddr_t blkno;
        int error;

        if (vp->v_type == VBLK || vp->v_type == VCHR)
                panic("ext2_strategy: spec");
        if (bp->b_blkno == bp->b_lblkno) {
                error = ext2_bmaparray(vp, bp->b_lblkno, &blkno, NULL, NULL);
                bp->b_blkno = blkno;
                if (error) {
                        bp->b_error = error;
                        bp->b_ioflags |= BIO_ERROR;
                        bufdone(bp);
                        return (0);
                }
                if ((long)bp->b_blkno == -1)
                        vfs_bio_clrbuf(bp);
        }
        if ((long)bp->b_blkno == -1) {
                bufdone(bp);
                return (0);
        }
        bp->b_iooffset = dbtob(bp->b_blkno);
        bo = VFSTOEXT2(vp->v_mount)->um_bo;
        BO_STRATEGY(bo, bp);
        return (0);
}

/*
 * Print out the contents of an inode.
 */
static int
ext2_print(struct vop_print_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct inode *ip = VTOI(vp);

        vn_printf(ip->i_devvp, "\tino %ju", (uintmax_t)ip->i_number);
        if (vp->v_type == VFIFO)
                fifo_printinfo(vp);
        printf("\n");
        return (0);
}

/*
 * Close wrapper for fifos.
 *
 * Update the times on the inode then do device close.
 */
static int
ext2fifo_close(struct vop_close_args *ap)
{
        struct vnode *vp = ap->a_vp;

        VI_LOCK(vp);
        if (vp->v_usecount > 1)
                ext2_itimes_locked(vp);
        VI_UNLOCK(vp);
        return (fifo_specops.vop_close(ap));
}

/*
 * Kqfilter wrapper for fifos.
 *
 * Fall through to ext2 kqfilter routines if needed 
 */
static int
ext2fifo_kqfilter(struct vop_kqfilter_args *ap)
{
        int error;

        error = fifo_specops.vop_kqfilter(ap);
        if (error)
                error = vfs_kqfilter(ap);
        return (error);
}

/*
 * Return POSIX pathconf information applicable to ext2 filesystems.
 */
static int
ext2_pathconf(struct vop_pathconf_args *ap)
{
        int error = 0;

        switch (ap->a_name) {
        case _PC_LINK_MAX:
                *ap->a_retval = EXT2_LINK_MAX;
                break;
        case _PC_NAME_MAX:
                *ap->a_retval = NAME_MAX;
                break;
        case _PC_PATH_MAX:
                *ap->a_retval = PATH_MAX;
                break;
        case _PC_PIPE_BUF:
                *ap->a_retval = PIPE_BUF;
                break;
        case _PC_CHOWN_RESTRICTED:
                *ap->a_retval = 1;
                break;
        case _PC_NO_TRUNC:
                *ap->a_retval = 1;
                break;
        case _PC_MIN_HOLE_SIZE:
                *ap->a_retval = ap->a_vp->v_mount->mnt_stat.f_iosize;
                break;
        case _PC_ASYNC_IO:
                /* _PC_ASYNC_IO should have been handled by upper layers. */
                KASSERT(0, ("_PC_ASYNC_IO should not get here"));
                error = EINVAL;
                break;
        case _PC_PRIO_IO:
                *ap->a_retval = 0;
                break;
        case _PC_SYNC_IO:
                *ap->a_retval = 0;
                break;
        case _PC_ALLOC_SIZE_MIN:
                *ap->a_retval = ap->a_vp->v_mount->mnt_stat.f_bsize;
                break;
        case _PC_FILESIZEBITS:
                *ap->a_retval = 64;
                break;
        case _PC_REC_INCR_XFER_SIZE:
                *ap->a_retval = ap->a_vp->v_mount->mnt_stat.f_iosize;
                break;
        case _PC_REC_MAX_XFER_SIZE:
                *ap->a_retval = -1; /* means ``unlimited'' */
                break;
        case _PC_REC_MIN_XFER_SIZE:
                *ap->a_retval = ap->a_vp->v_mount->mnt_stat.f_iosize;
                break;
        case _PC_REC_XFER_ALIGN:
                *ap->a_retval = PAGE_SIZE;
                break;
        case _PC_SYMLINK_MAX:
                *ap->a_retval = MAXPATHLEN;
                break;

        default:
                error = EINVAL;
                break;
        }
        return (error);
}

/*
 * Vnode pointer to File handle
 */
/* ARGSUSED */
static int
ext2_vptofh(struct vop_vptofh_args *ap)
{
        struct inode *ip;
        struct ufid *ufhp;

        ip = VTOI(ap->a_vp);
        ufhp = (struct ufid *)ap->a_fhp;
        ufhp->ufid_len = sizeof(struct ufid);
        ufhp->ufid_ino = ip->i_number;
        ufhp->ufid_gen = ip->i_gen;
        return (0);
}

/*
 * Initialize the vnode associated with a new inode, handle aliased
 * vnodes.
 */
int
ext2_vinit(struct mount *mntp, struct vop_vector *fifoops, struct vnode **vpp)
{
        struct inode *ip;
        struct vnode *vp;

        vp = *vpp;
        ip = VTOI(vp);
        vp->v_type = IFTOVT(ip->i_mode);
        if (vp->v_type == VFIFO)
                vp->v_op = fifoops;

        if (ip->i_number == EXT2_ROOTINO)
                vp->v_vflag |= VV_ROOT;
        ip->i_modrev = init_va_filerev();
        *vpp = vp;
        return (0);
}

/*
 * Allocate a new inode.
 */
static int
ext2_makeinode(int mode, struct vnode *dvp, struct vnode **vpp,
    struct componentname *cnp)
{
        struct inode *ip, *pdir;
        struct vnode *tvp;
        int error;

        pdir = VTOI(dvp);
#ifdef INVARIANTS
        if ((cnp->cn_flags & HASBUF) == 0)
                panic("ext2_makeinode: no name");
#endif
        *vpp = NULL;
        if ((mode & IFMT) == 0)
                mode |= IFREG;

        error = ext2_valloc(dvp, mode, cnp->cn_cred, &tvp);
        if (error) {
                return (error);
        }
        ip = VTOI(tvp);
        ip->i_gid = pdir->i_gid;
#ifdef SUIDDIR
        {
                /*
                 * if we are
                 * not the owner of the directory,
                 * and we are hacking owners here, (only do this where told to)
                 * and we are not giving it TOO root, (would subvert quotas)
                 * then go ahead and give it to the other user.
                 * Note that this drops off the execute bits for security.
                 */
                if ( (dvp->v_mount->mnt_flag & MNT_SUIDDIR) &&
                     (pdir->i_mode & ISUID) &&
                     (pdir->i_uid != cnp->cn_cred->cr_uid) && pdir->i_uid) {
                        ip->i_uid = pdir->i_uid;
                        mode &= ~07111;
                } else {
                        ip->i_uid = cnp->cn_cred->cr_uid;
                }
        }
#else
        ip->i_uid = cnp->cn_cred->cr_uid;
#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)) {
                if (priv_check_cred(cnp->cn_cred, PRIV_VFS_RETAINSUGID, 0))
                        ip->i_mode &= ~ISGID;
        }

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

        /*
         * Make sure inode goes to disk before directory entry.
         */
        error = ext2_update(tvp, !DOINGASYNC(tvp));
        if (error)
                goto bad;
        error = ext2_direnter(ip, dvp, cnp);
        if (error)
                goto bad;

        *vpp = tvp;
        return (0);

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

/*
 * Vnode op for reading.
 */
static int
ext2_read(struct vop_read_args *ap)
{
        struct vnode *vp;
        struct inode *ip;
        int error;

        vp = ap->a_vp;
        ip = VTOI(vp);

        /*EXT4_EXT_LOCK(ip);*/
        if (ip->i_flag & IN_E4EXTENTS)
                error = ext4_ext_read(ap);
        else
                error = ext2_ind_read(ap);
        /*EXT4_EXT_UNLOCK(ip);*/
        return (error);
}

/*
 * Vnode op for reading.
 */
static int
ext2_ind_read(struct vop_read_args *ap)
{
        struct vnode *vp;
        struct inode *ip;
        struct uio *uio;
        struct m_ext2fs *fs;
        struct buf *bp;
        daddr_t lbn, nextlbn;
        off_t bytesinfile;
        long size, xfersize, blkoffset;
        int error, orig_resid, seqcount;
        int ioflag;

        vp = ap->a_vp;
        uio = ap->a_uio;
        ioflag = ap->a_ioflag;

        seqcount = ap->a_ioflag >> IO_SEQSHIFT;
        ip = VTOI(vp);

#ifdef INVARIANTS
        if (uio->uio_rw != UIO_READ)
                panic("%s: mode", "ext2_read");

        if (vp->v_type == VLNK) {
                if ((int)ip->i_size < vp->v_mount->mnt_maxsymlinklen)
                        panic("%s: short symlink", "ext2_read");
        } else if (vp->v_type != VREG && vp->v_type != VDIR)
                panic("%s: type %d", "ext2_read", vp->v_type);
#endif
        orig_resid = uio->uio_resid;
        KASSERT(orig_resid >= 0, ("ext2_read: uio->uio_resid < 0"));
        if (orig_resid == 0)
                return (0);
        KASSERT(uio->uio_offset >= 0, ("ext2_read: uio->uio_offset < 0"));
        fs = ip->i_e2fs;
        if (uio->uio_offset < ip->i_size &&
            uio->uio_offset >= fs->e2fs_maxfilesize)
                return (EOVERFLOW);

        for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) {
                if ((bytesinfile = ip->i_size - uio->uio_offset) <= 0)
                        break;
                lbn = lblkno(fs, uio->uio_offset);
                nextlbn = lbn + 1;
                size = blksize(fs, ip, lbn);
                blkoffset = blkoff(fs, uio->uio_offset);

                xfersize = fs->e2fs_fsize - blkoffset;
                if (uio->uio_resid < xfersize)
                        xfersize = uio->uio_resid;
                if (bytesinfile < xfersize)
                        xfersize = bytesinfile;

                if (lblktosize(fs, nextlbn) >= ip->i_size)
                        error = bread(vp, lbn, size, NOCRED, &bp);
                else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
                        error = cluster_read(vp, ip->i_size, lbn, size,
                            NOCRED, blkoffset + uio->uio_resid, seqcount,
                            0, &bp);
                } else if (seqcount > 1) {
                        u_int nextsize = blksize(fs, ip, nextlbn);
                        error = breadn(vp, lbn,
                            size, &nextlbn, &nextsize, 1, NOCRED, &bp);
                } else
                        error = bread(vp, lbn, size, NOCRED, &bp);
                if (error) {
                        brelse(bp);
                        bp = NULL;
                        break;
                }

                /*
                 * If IO_DIRECT then set B_DIRECT for the buffer.  This
                 * will cause us to attempt to release the buffer later on
                 * and will cause the buffer cache to attempt to free the
                 * underlying pages.
                 */
                if (ioflag & IO_DIRECT)
                        bp->b_flags |= B_DIRECT;

                /*
                 * We should only get non-zero b_resid when an I/O error
                 * has occurred, which should cause us to break above.
                 * However, if the short read did not cause an error,
                 * then we want to ensure that we do not uiomove bad
                 * or uninitialized data.
                 */
                size -= bp->b_resid;
                if (size < xfersize) {
                        if (size == 0)
                                break;
                        xfersize = size;
                }
                error = uiomove((char *)bp->b_data + blkoffset,
                        (int)xfersize, uio);
                if (error)
                        break;

                if (ioflag & (IO_VMIO|IO_DIRECT)) {
                        /*
                         * If it's VMIO or direct I/O, then we don't
                         * need the buf, mark it available for
                         * freeing. If it's non-direct VMIO, the VM has
                         * the data.
                         */
                        bp->b_flags |= B_RELBUF;
                        brelse(bp);
                } else {
                        /*
                         * Otherwise let whoever
                         * made the request take care of
                         * freeing it. We just queue
                         * it onto another list.
                         */
                        bqrelse(bp);
                }
        }

        /* 
         * This can only happen in the case of an error
         * because the loop above resets bp to NULL on each iteration
         * and on normal completion has not set a new value into it.
         * so it must have come from a 'break' statement
         */
        if (bp != NULL) {
                if (ioflag & (IO_VMIO|IO_DIRECT)) {
                        bp->b_flags |= B_RELBUF;
                        brelse(bp);
                } else {
                        bqrelse(bp);
                }
        }

        if ((error == 0 || uio->uio_resid != orig_resid) &&
            (vp->v_mount->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0)
                ip->i_flag |= IN_ACCESS;
        return (error);
}

static int
ext2_ioctl(struct vop_ioctl_args *ap)
{

        switch (ap->a_command) {
        case FIOSEEKDATA:
        case FIOSEEKHOLE:
                return (vn_bmap_seekhole(ap->a_vp, ap->a_command,
                    (off_t *)ap->a_data, ap->a_cred));
        default:
                return (ENOTTY);
        }
}

/*
 * this function handles ext4 extents block mapping
 */
static int
ext4_ext_read(struct vop_read_args *ap)
{
        struct vnode *vp;
        struct inode *ip;
        struct uio *uio;
        struct m_ext2fs *fs;
        struct buf *bp;
        struct ext4_extent nex, *ep;
        struct ext4_extent_path path;
        daddr_t lbn, newblk;
        off_t bytesinfile;
        int cache_type;
        ssize_t orig_resid;
        int error;
        long size, xfersize, blkoffset;

        vp = ap->a_vp;
        ip = VTOI(vp);
        uio = ap->a_uio;
        memset(&path, 0, sizeof(path));

        orig_resid = uio->uio_resid;
        KASSERT(orig_resid >= 0, ("%s: uio->uio_resid < 0", __func__));
        if (orig_resid == 0)
                return (0);
        KASSERT(uio->uio_offset >= 0, ("%s: uio->uio_offset < 0", __func__));
        fs = ip->i_e2fs;
        if (uio->uio_offset < ip->i_size && uio->uio_offset >= fs->e2fs_maxfilesize)
                return (EOVERFLOW);

        while (uio->uio_resid > 0) {
                if ((bytesinfile = ip->i_size - uio->uio_offset) <= 0)
                        break;
                lbn = lblkno(fs, uio->uio_offset);
                size = blksize(fs, ip, lbn);
                blkoffset = blkoff(fs, uio->uio_offset);

                xfersize = fs->e2fs_fsize - blkoffset;
                xfersize = MIN(xfersize, uio->uio_resid);
                xfersize = MIN(xfersize, bytesinfile);

                /* get block from ext4 extent cache */
                cache_type = ext4_ext_in_cache(ip, lbn, &nex);
                switch (cache_type) {
                case EXT4_EXT_CACHE_NO:
                        ext4_ext_find_extent(fs, ip, lbn, &path);
                        ep = path.ep_ext;
                        if (ep == NULL)
                                return (EIO);

                        ext4_ext_put_cache(ip, ep, EXT4_EXT_CACHE_IN);

                        newblk = lbn - ep->e_blk + (ep->e_start_lo |
                            (daddr_t)ep->e_start_hi << 32);

                        if (path.ep_bp != NULL) {
                                brelse(path.ep_bp);
                                path.ep_bp = NULL;
                        }
                        break;

                case EXT4_EXT_CACHE_GAP:
                        /* block has not been allocated yet */
                        return (0);

                case EXT4_EXT_CACHE_IN:
                        newblk = lbn - nex.e_blk + (nex.e_start_lo |
                            (daddr_t)nex.e_start_hi << 32);
                        break;

                default:
                        panic("%s: invalid cache type", __func__);
                }

                error = bread(ip->i_devvp, fsbtodb(fs, newblk), size, NOCRED, &bp);
                if (error) {
                        brelse(bp);
                        return (error);
                }

                size -= bp->b_resid;
                if (size < xfersize) {
                        if (size == 0) {
                                bqrelse(bp);
                                break;
                        }
                        xfersize = size;
                }
                error = uiomove(bp->b_data + blkoffset, (int)xfersize, uio);
                bqrelse(bp);
                if (error)
                        return (error);
        }

        return (0);
}

/*
 * Vnode op for writing.
 */
static int
ext2_write(struct vop_write_args *ap)
{
        struct vnode *vp;
        struct uio *uio;
        struct inode *ip;
        struct m_ext2fs *fs;
        struct buf *bp;
        daddr_t lbn;
        off_t osize;
        int blkoffset, error, flags, ioflag, resid, size, seqcount, xfersize;

        ioflag = ap->a_ioflag;
        uio = ap->a_uio;
        vp = ap->a_vp;

        seqcount = ioflag >> IO_SEQSHIFT;
        ip = VTOI(vp);

#ifdef INVARIANTS
        if (uio->uio_rw != UIO_WRITE)
                panic("%s: mode", "ext2_write");
#endif

        switch (vp->v_type) {
        case VREG:
                if (ioflag & IO_APPEND)
                        uio->uio_offset = ip->i_size;
                if ((ip->i_flags & APPEND) && uio->uio_offset != ip->i_size)
                        return (EPERM);
                /* FALLTHROUGH */
        case VLNK:
                break;
        case VDIR:
                /* XXX differs from ffs -- this is called from ext2_mkdir(). */
                if ((ioflag & IO_SYNC) == 0)
                panic("ext2_write: nonsync dir write");
                break;
        default:
                panic("ext2_write: type %p %d (%jd,%jd)", (void *)vp,
                    vp->v_type, (intmax_t)uio->uio_offset,
                    (intmax_t)uio->uio_resid);
        }

        KASSERT(uio->uio_resid >= 0, ("ext2_write: uio->uio_resid < 0"));
        KASSERT(uio->uio_offset >= 0, ("ext2_write: uio->uio_offset < 0"));
        fs = ip->i_e2fs;
        if ((uoff_t)uio->uio_offset + uio->uio_resid > fs->e2fs_maxfilesize)
                return (EFBIG);
        /*
         * Maybe this should be above the vnode op call, but so long as
         * file servers have no limits, I don't think it matters.
         */
        if (vn_rlimit_fsize(vp, uio, uio->uio_td))
                return (EFBIG);

        resid = uio->uio_resid;
        osize = ip->i_size;
        if (seqcount > BA_SEQMAX)
                flags = BA_SEQMAX << BA_SEQSHIFT;
        else
                flags = seqcount << BA_SEQSHIFT;
        if ((ioflag & IO_SYNC) && !DOINGASYNC(vp))
                flags |= IO_SYNC;

        for (error = 0; uio->uio_resid > 0;) {
                lbn = lblkno(fs, uio->uio_offset);
                blkoffset = blkoff(fs, uio->uio_offset);
                xfersize = fs->e2fs_fsize - blkoffset;
                if (uio->uio_resid < xfersize)
                        xfersize = uio->uio_resid;
                if (uio->uio_offset + xfersize > ip->i_size)
                        vnode_pager_setsize(vp, uio->uio_offset + xfersize);

                /*
                 * We must perform a read-before-write if the transfer size
                 * does not cover the entire buffer.
                 */
                if (fs->e2fs_bsize > xfersize)
                        flags |= BA_CLRBUF;
                else
                        flags &= ~BA_CLRBUF;
                error = ext2_balloc(ip, lbn, blkoffset + xfersize,
                    ap->a_cred, &bp, flags);
                if (error != 0)
                        break;

                if ((ioflag & (IO_SYNC|IO_INVAL)) == (IO_SYNC|IO_INVAL))
                        bp->b_flags |= B_NOCACHE;
                if (uio->uio_offset + xfersize > ip->i_size)
                        ip->i_size = uio->uio_offset + xfersize;
                size = blksize(fs, ip, lbn) - bp->b_resid;
                if (size < xfersize)
                        xfersize = size;

                error =
                    uiomove((char *)bp->b_data + blkoffset, (int)xfersize, uio);
                /*
                 * If the buffer is not already filled and we encounter an
                 * error while trying to fill it, we have to clear out any
                 * garbage data from the pages instantiated for the buffer.
                 * If we do not, a failed uiomove() during a write can leave
                 * the prior contents of the pages exposed to a userland mmap.
                 *
                 * Note that we need only clear buffers with a transfer size
                 * equal to the block size because buffers with a shorter
                 * transfer size were cleared above by the call to ext2_balloc()
                 * with the BA_CLRBUF flag set.
                 *
                 * If the source region for uiomove identically mmaps the
                 * buffer, uiomove() performed the NOP copy, and the buffer
                 * content remains valid because the page fault handler
                 * validated the pages.
                 */
                if (error != 0 && (bp->b_flags & B_CACHE) == 0 &&
                    fs->e2fs_bsize == xfersize)
                        vfs_bio_clrbuf(bp);
                if (ioflag & (IO_VMIO|IO_DIRECT)) {
                        bp->b_flags |= B_RELBUF;
                }

                /*
                 * If IO_SYNC each buffer is written synchronously.  Otherwise
                 * if we have a severe page deficiency write the buffer
                 * asynchronously.  Otherwise try to cluster, and if that
                 * doesn't do it then either do an async write (if O_DIRECT),
                 * or a delayed write (if not).
                 */
                if (ioflag & IO_SYNC) {
                        (void)bwrite(bp);
                } else if (vm_page_count_severe() ||
                    buf_dirty_count_severe() ||
                    (ioflag & IO_ASYNC)) {
                        bp->b_flags |= B_CLUSTEROK;
                        bawrite(bp);
                } else if (xfersize + blkoffset == fs->e2fs_fsize) {
                        if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0) {
                                bp->b_flags |= B_CLUSTEROK;
                                cluster_write(vp, bp, ip->i_size, seqcount, 0);
                        } else {
                                bawrite(bp);
                        }
                } else if (ioflag & IO_DIRECT) {
                        bp->b_flags |= B_CLUSTEROK;
                        bawrite(bp);
                } else {
                        bp->b_flags |= B_CLUSTEROK;
                        bdwrite(bp);
                }
                if (error || xfersize == 0)
                        break;
        }
        /*
         * If we successfully wrote any data, and we are not the superuser
         * we clear the setuid and setgid bits as a precaution against
         * tampering.
         */
        if ((ip->i_mode & (ISUID | ISGID)) && resid > uio->uio_resid &&
            ap->a_cred) {
                if (priv_check_cred(ap->a_cred, PRIV_VFS_RETAINSUGID, 0))
                        ip->i_mode &= ~(ISUID | ISGID);
        }
        if (error) {
                if (ioflag & IO_UNIT) {
                        (void)ext2_truncate(vp, osize,
                            ioflag & IO_SYNC, ap->a_cred, uio->uio_td);
                        uio->uio_offset -= resid - uio->uio_resid;
                        uio->uio_resid = resid;
                }
        }
        if (uio->uio_resid != resid) {
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                if (ioflag & IO_SYNC)
                        error = ext2_update(vp, 1);
        }
        return (error);
}