FreeBSD/Linux Kernel Cross Reference
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: releng/11.1/sys/fs/ext2fs/ext2_vnops.c 311231 2017-01-04 02:42:17Z pfg $
     */
    
    #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_getpages_async =   vnode_pager_local_getpages_async,
           .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);
                   ip->i_flag |= IN_CHANGE | IN_MODIFIED;
                   if (vap->va_atime.tv_sec != VNOVAL) {
                           ip->i_flag &= ~IN_ACCESS;
                           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_flag &= ~IN_UPDATE;
                           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.  IN_RENAME is not sufficient
                    * to protect against directory races due to timing windows,
                    * so we can't panic here.
                    */
                   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) {
                  /*
                   * From name resolves to a different inode.  IN_RENAME is
                   * not sufficient protection against timing window races
                   * so we can't panic here.
                   */
          } 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)
  {
          static unsigned char zeroes[EXT2_MAX_BLOCK_SIZE];
          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);
                          if (path.ep_is_sparse)
                                  ep = &path.ep_sparse_ext;
                          else
                                  ep = path.ep_ext;
                          if (ep == NULL)
                                  return (EIO);
  
                          ext4_ext_put_cache(ip, ep,
                              path.ep_is_sparse ? EXT4_EXT_CACHE_GAP : 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 */
                          break;
  
                  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__);
                  }
  
                  if (cache_type == EXT4_EXT_CACHE_GAP ||
                      (cache_type == EXT4_EXT_CACHE_NO && path.ep_is_sparse)) {
                          if (xfersize > sizeof(zeroes))
                                  xfersize = sizeof(zeroes);
                          error = uiomove(zeroes, xfersize, uio);
                          if (error)
                                  return (error);
                  } else {
                          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, 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);
  }

Cache object: 44c5c83d3f751e74b3151a1db57b084a