FreeBSD/Linux Kernel Cross Reference
sys/fs/fuse/fuse_vnops.c

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 2007-2009 Google Inc. and Amit Singh
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions are
      * met:
     *
     * * Redistributions of source code must retain the above copyright
     *   notice, this list of conditions and the following disclaimer.
     * * 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.
     * * Neither the name of Google Inc. 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 COPYRIGHT HOLDERS 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 COPYRIGHT
     * OWNER 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.
     *
     * Copyright (C) 2005 Csaba Henk.
     * All rights reserved.
     *
     * Copyright (c) 2019 The FreeBSD Foundation
     *
     * Portions of this software were developed by BFF Storage Systems, LLC under
     * sponsorship from the FreeBSD Foundation.
     *
     * 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.
     *
     * THIS SOFTWARE IS PROVIDED BY AUTHOR 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 AUTHOR 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.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/module.h>
    #include <sys/systm.h>
    #include <sys/errno.h>
    #include <sys/kernel.h>
    #include <sys/conf.h>
    #include <sys/filio.h>
    #include <sys/uio.h>
    #include <sys/malloc.h>
    #include <sys/queue.h>
    #include <sys/limits.h>
    #include <sys/lock.h>
    #include <sys/rwlock.h>
    #include <sys/sx.h>
    #include <sys/proc.h>
    #include <sys/mount.h>
    #include <sys/vnode.h>
    #include <sys/namei.h>
    #include <sys/extattr.h>
    #include <sys/stat.h>
    #include <sys/unistd.h>
    #include <sys/filedesc.h>
    #include <sys/file.h>
    #include <sys/fcntl.h>
    #include <sys/dirent.h>
    #include <sys/bio.h>
    #include <sys/buf.h>
    #include <sys/sysctl.h>
    #include <sys/vmmeter.h>
    
    #include <vm/vm.h>
    #include <vm/vm_extern.h>
    #include <vm/pmap.h>
    #include <vm/vm_map.h>
   #include <vm/vm_page.h>
   #include <vm/vm_param.h>
   #include <vm/vm_object.h>
   #include <vm/vm_pager.h>
   #include <vm/vnode_pager.h>
   #include <vm/vm_object.h>
   
   #include "fuse.h"
   #include "fuse_file.h"
   #include "fuse_internal.h"
   #include "fuse_ipc.h"
   #include "fuse_node.h"
   #include "fuse_io.h"
   
   #include <sys/priv.h>
   
   /* Maximum number of hardlinks to a single FUSE file */
   #define FUSE_LINK_MAX                      UINT32_MAX
   
   SDT_PROVIDER_DECLARE(fusefs);
   /* 
    * Fuse trace probe:
    * arg0: verbosity.  Higher numbers give more verbose messages
    * arg1: Textual message
    */
   SDT_PROBE_DEFINE2(fusefs, , vnops, trace, "int", "char*");
   
   /* vnode ops */
   static vop_access_t fuse_vnop_access;
   static vop_advlock_t fuse_vnop_advlock;
   static vop_allocate_t fuse_vnop_allocate;
   static vop_bmap_t fuse_vnop_bmap;
   static vop_close_t fuse_fifo_close;
   static vop_close_t fuse_vnop_close;
   static vop_copy_file_range_t fuse_vnop_copy_file_range;
   static vop_create_t fuse_vnop_create;
   static vop_deallocate_t fuse_vnop_deallocate;
   static vop_deleteextattr_t fuse_vnop_deleteextattr;
   static vop_fdatasync_t fuse_vnop_fdatasync;
   static vop_fsync_t fuse_vnop_fsync;
   static vop_getattr_t fuse_vnop_getattr;
   static vop_getextattr_t fuse_vnop_getextattr;
   static vop_inactive_t fuse_vnop_inactive;
   static vop_ioctl_t fuse_vnop_ioctl;
   static vop_link_t fuse_vnop_link;
   static vop_listextattr_t fuse_vnop_listextattr;
   static vop_lookup_t fuse_vnop_lookup;
   static vop_mkdir_t fuse_vnop_mkdir;
   static vop_mknod_t fuse_vnop_mknod;
   static vop_open_t fuse_vnop_open;
   static vop_pathconf_t fuse_vnop_pathconf;
   static vop_read_t fuse_vnop_read;
   static vop_readdir_t fuse_vnop_readdir;
   static vop_readlink_t fuse_vnop_readlink;
   static vop_reclaim_t fuse_vnop_reclaim;
   static vop_remove_t fuse_vnop_remove;
   static vop_rename_t fuse_vnop_rename;
   static vop_rmdir_t fuse_vnop_rmdir;
   static vop_setattr_t fuse_vnop_setattr;
   static vop_setextattr_t fuse_vnop_setextattr;
   static vop_strategy_t fuse_vnop_strategy;
   static vop_symlink_t fuse_vnop_symlink;
   static vop_write_t fuse_vnop_write;
   static vop_getpages_t fuse_vnop_getpages;
   static vop_print_t fuse_vnop_print;
   static vop_vptofh_t fuse_vnop_vptofh;
   
   struct vop_vector fuse_fifoops = {
           .vop_default =          &fifo_specops,
           .vop_access =           fuse_vnop_access,
           .vop_close =            fuse_fifo_close,
           .vop_fsync =            fuse_vnop_fsync,
           .vop_getattr =          fuse_vnop_getattr,
           .vop_inactive =         fuse_vnop_inactive,
           .vop_pathconf =         fuse_vnop_pathconf,
           .vop_print =            fuse_vnop_print,
           .vop_read =             VOP_PANIC,
           .vop_reclaim =          fuse_vnop_reclaim,
           .vop_setattr =          fuse_vnop_setattr,
           .vop_write =            VOP_PANIC,
           .vop_vptofh =           fuse_vnop_vptofh,
   };
   VFS_VOP_VECTOR_REGISTER(fuse_fifoops);
   
   struct vop_vector fuse_vnops = {
           .vop_allocate = fuse_vnop_allocate,
           .vop_default = &default_vnodeops,
           .vop_access = fuse_vnop_access,
           .vop_advlock = fuse_vnop_advlock,
           .vop_bmap = fuse_vnop_bmap,
           .vop_close = fuse_vnop_close,
           .vop_copy_file_range = fuse_vnop_copy_file_range,
           .vop_create = fuse_vnop_create,
           .vop_deallocate = fuse_vnop_deallocate,
           .vop_deleteextattr = fuse_vnop_deleteextattr,
           .vop_fsync = fuse_vnop_fsync,
           .vop_fdatasync = fuse_vnop_fdatasync,
           .vop_getattr = fuse_vnop_getattr,
           .vop_getextattr = fuse_vnop_getextattr,
           .vop_inactive = fuse_vnop_inactive,
           .vop_ioctl = fuse_vnop_ioctl,
           .vop_link = fuse_vnop_link,
           .vop_listextattr = fuse_vnop_listextattr,
           .vop_lookup = fuse_vnop_lookup,
           .vop_mkdir = fuse_vnop_mkdir,
           .vop_mknod = fuse_vnop_mknod,
           .vop_open = fuse_vnop_open,
           .vop_pathconf = fuse_vnop_pathconf,
           /*
            * TODO: implement vop_poll after upgrading to protocol 7.21.
            * FUSE_POLL was added in protocol 7.11, but it's kind of broken until
            * 7.21, which adds the ability for the client to choose which poll
            * events it wants, and for a client to deregister a file handle
            */
           .vop_read = fuse_vnop_read,
           .vop_readdir = fuse_vnop_readdir,
           .vop_readlink = fuse_vnop_readlink,
           .vop_reclaim = fuse_vnop_reclaim,
           .vop_remove = fuse_vnop_remove,
           .vop_rename = fuse_vnop_rename,
           .vop_rmdir = fuse_vnop_rmdir,
           .vop_setattr = fuse_vnop_setattr,
           .vop_setextattr = fuse_vnop_setextattr,
           .vop_strategy = fuse_vnop_strategy,
           .vop_symlink = fuse_vnop_symlink,
           .vop_write = fuse_vnop_write,
           .vop_getpages = fuse_vnop_getpages,
           .vop_print = fuse_vnop_print,
           .vop_vptofh = fuse_vnop_vptofh,
   };
   VFS_VOP_VECTOR_REGISTER(fuse_vnops);
   
   uma_zone_t fuse_pbuf_zone;
   
   /* Check permission for extattr operations, much like extattr_check_cred */
   static int
   fuse_extattr_check_cred(struct vnode *vp, int ns, struct ucred *cred,
           struct thread *td, accmode_t accmode)
   {
           struct mount *mp = vnode_mount(vp);
           struct fuse_data *data = fuse_get_mpdata(mp);
           int default_permissions = data->dataflags & FSESS_DEFAULT_PERMISSIONS;
   
           /*
            * Kernel-invoked always succeeds.
            */
           if (cred == NOCRED)
                   return (0);
   
           /*
            * Do not allow privileged processes in jail to directly manipulate
            * system attributes.
            */
           switch (ns) {
           case EXTATTR_NAMESPACE_SYSTEM:
                   if (default_permissions) {
                           return (priv_check_cred(cred, PRIV_VFS_EXTATTR_SYSTEM));
                   }
                   return (0);
           case EXTATTR_NAMESPACE_USER:
                   if (default_permissions) {
                           return (fuse_internal_access(vp, accmode, td, cred));
                   }
                   return (0);
           default:
                   return (EPERM);
           }
   }
   
   /* Get a filehandle for a directory */
   static int
   fuse_filehandle_get_dir(struct vnode *vp, struct fuse_filehandle **fufhp,
           struct ucred *cred, pid_t pid)
   {
           if (fuse_filehandle_get(vp, FREAD, fufhp, cred, pid) == 0)
                   return 0;
           return fuse_filehandle_get(vp, FEXEC, fufhp, cred, pid);
   }
   
   /* Send FUSE_FLUSH for this vnode */
   static int
   fuse_flush(struct vnode *vp, struct ucred *cred, pid_t pid, int fflag)
   {
           struct fuse_flush_in *ffi;
           struct fuse_filehandle *fufh;
           struct fuse_dispatcher fdi;
           struct thread *td = curthread;
           struct mount *mp = vnode_mount(vp);
           int err;
   
           if (fsess_not_impl(vnode_mount(vp), FUSE_FLUSH))
                   return 0;
   
           err = fuse_filehandle_getrw(vp, fflag, &fufh, cred, pid);
           if (err)
                   return err;
   
           fdisp_init(&fdi, sizeof(*ffi));
           fdisp_make_vp(&fdi, FUSE_FLUSH, vp, td, cred);
           ffi = fdi.indata;
           ffi->fh = fufh->fh_id;
           /* 
            * If the file has a POSIX lock then we're supposed to set lock_owner.
            * If not, then lock_owner is undefined.  So we may as well always set
            * it.
            */
           ffi->lock_owner = td->td_proc->p_pid;
   
           err = fdisp_wait_answ(&fdi);
           if (err == ENOSYS) {
                   fsess_set_notimpl(mp, FUSE_FLUSH);
                   err = 0;
           }
           fdisp_destroy(&fdi);
           return err;
   }
   
   /* Close wrapper for fifos.  */
   static int
   fuse_fifo_close(struct vop_close_args *ap)
   {
           return (fifo_specops.vop_close(ap));
   }
   
   /* Invalidate a range of cached data, whether dirty of not */
   static int
   fuse_inval_buf_range(struct vnode *vp, off_t filesize, off_t start, off_t end)
   {
           struct buf *bp;
           daddr_t left_lbn, end_lbn, right_lbn;
           off_t new_filesize;
           int iosize, left_on, right_on, right_blksize;
   
           iosize = fuse_iosize(vp);
           left_lbn = start / iosize;
           end_lbn = howmany(end, iosize);
           left_on = start & (iosize - 1);
           if (left_on != 0) {
                   bp = getblk(vp, left_lbn, iosize, PCATCH, 0, 0);
                   if ((bp->b_flags & B_CACHE) != 0 && bp->b_dirtyend >= left_on) {
                           /*
                            * Flush the dirty buffer, because we don't have a
                            * byte-granular way to record which parts of the
                            * buffer are valid.
                            */
                           bwrite(bp);
                           if (bp->b_error)
                                   return (bp->b_error);
                   } else {
                           brelse(bp);
                   }
           }
           right_on = end & (iosize - 1);
           if (right_on != 0) {
                   right_lbn = end / iosize;
                   new_filesize = MAX(filesize, end);
                   right_blksize = MIN(iosize, new_filesize - iosize * right_lbn);
                   bp = getblk(vp, right_lbn, right_blksize, PCATCH, 0, 0);
                   if ((bp->b_flags & B_CACHE) != 0 && bp->b_dirtyoff < right_on) {
                           /*
                            * Flush the dirty buffer, because we don't have a
                            * byte-granular way to record which parts of the
                            * buffer are valid.
                            */
                           bwrite(bp);
                           if (bp->b_error)
                                   return (bp->b_error);
                   } else {
                           brelse(bp);
                   }
           }
   
           v_inval_buf_range(vp, left_lbn, end_lbn, iosize);
           return (0);
   }
   
   
   /* Send FUSE_LSEEK for this node */
   static int
   fuse_vnop_do_lseek(struct vnode *vp, struct thread *td, struct ucred *cred,
           pid_t pid, off_t *offp, int whence)
   {
           struct fuse_dispatcher fdi;
           struct fuse_filehandle *fufh;
           struct fuse_lseek_in *flsi;
           struct fuse_lseek_out *flso;
           struct mount *mp = vnode_mount(vp);
           int err;
   
           ASSERT_VOP_LOCKED(vp, __func__);
   
           err = fuse_filehandle_getrw(vp, FREAD, &fufh, cred, pid);
           if (err)
                   return (err);
           fdisp_init(&fdi, sizeof(*flsi));
           fdisp_make_vp(&fdi, FUSE_LSEEK, vp, td, cred);
           flsi = fdi.indata;
           flsi->fh = fufh->fh_id;
           flsi->offset = *offp;
           flsi->whence = whence;
           err = fdisp_wait_answ(&fdi);
           if (err == ENOSYS) {
                   fsess_set_notimpl(mp, FUSE_LSEEK);
           } else if (err == 0) {
                   fsess_set_impl(mp, FUSE_LSEEK);
                   flso = fdi.answ;
                   *offp = flso->offset;
           }
           fdisp_destroy(&fdi);
   
           return (err);
   }
   
   /*
       struct vnop_access_args {
           struct vnode *a_vp;
   #if VOP_ACCESS_TAKES_ACCMODE_T
           accmode_t a_accmode;
   #else
           int a_mode;
   #endif
           struct ucred *a_cred;
           struct thread *a_td;
       };
   */
   static int
   fuse_vnop_access(struct vop_access_args *ap)
   {
           struct vnode *vp = ap->a_vp;
           int accmode = ap->a_accmode;
           struct ucred *cred = ap->a_cred;
   
           struct fuse_data *data = fuse_get_mpdata(vnode_mount(vp));
   
           int err;
   
           if (fuse_isdeadfs(vp)) {
                   if (vnode_isvroot(vp)) {
                           return 0;
                   }
                   return ENXIO;
           }
           if (!(data->dataflags & FSESS_INITED)) {
                   if (vnode_isvroot(vp)) {
                           if (priv_check_cred(cred, PRIV_VFS_ADMIN) ||
                               (fuse_match_cred(data->daemoncred, cred) == 0)) {
                                   return 0;
                           }
                   }
                   return EBADF;
           }
           if (vnode_islnk(vp)) {
                   return 0;
           }
   
           err = fuse_internal_access(vp, accmode, ap->a_td, ap->a_cred);
           return err;
   }
   
   /*
    * struct vop_advlock_args {
    *      struct vop_generic_args a_gen;
    *      struct vnode *a_vp;
    *      void *a_id;
    *      int a_op;
    *      struct flock *a_fl;
    *      int a_flags;
    * }
    */
   static int
   fuse_vnop_advlock(struct vop_advlock_args *ap)
   {
           struct vnode *vp = ap->a_vp;
           struct flock *fl = ap->a_fl;
           struct thread *td = curthread;
           struct ucred *cred = td->td_ucred;
           pid_t pid = td->td_proc->p_pid;
           struct fuse_filehandle *fufh;
           struct fuse_dispatcher fdi;
           struct fuse_lk_in *fli;
           struct fuse_lk_out *flo;
           struct vattr vattr;
           enum fuse_opcode op;
           off_t size, start;
           int dataflags, err;
           int flags = ap->a_flags;
   
           dataflags = fuse_get_mpdata(vnode_mount(vp))->dataflags;
   
           if (fuse_isdeadfs(vp)) {
                   return ENXIO;
           }
   
           switch(ap->a_op) {
           case F_GETLK:
                   op = FUSE_GETLK;
                   break;
           case F_SETLK:
                   if (flags & F_WAIT)
                           op = FUSE_SETLKW;
                   else
                           op = FUSE_SETLK;
                   break;
           case F_UNLCK:
                   op = FUSE_SETLK;
                   break;
           default:
                   return EINVAL;
           }
   
           if (!(dataflags & FSESS_POSIX_LOCKS))
                   return vop_stdadvlock(ap);
           /* FUSE doesn't properly support flock until protocol 7.17 */
           if (flags & F_FLOCK)
                   return vop_stdadvlock(ap);
   
           vn_lock(vp, LK_SHARED | LK_RETRY);
   
           switch (fl->l_whence) {
           case SEEK_SET:
           case SEEK_CUR:
                   /*
                    * Caller is responsible for adding any necessary offset
                    * when SEEK_CUR is used.
                    */
                   start = fl->l_start;
                   break;
   
           case SEEK_END:
                   err = fuse_internal_getattr(vp, &vattr, cred, td);
                   if (err)
                           goto out;
                   size = vattr.va_size;
                   if (size > OFF_MAX ||
                       (fl->l_start > 0 && size > OFF_MAX - fl->l_start)) {
                           err = EOVERFLOW;
                           goto out;
                   }
                   start = size + fl->l_start;
                   break;
   
           default:
                   return (EINVAL);
           }
   
           err = fuse_filehandle_get_anyflags(vp, &fufh, cred, pid);
           if (err)
                   goto out;
   
           fdisp_init(&fdi, sizeof(*fli));
   
           fdisp_make_vp(&fdi, op, vp, td, cred);
           fli = fdi.indata;
           fli->fh = fufh->fh_id;
           fli->owner = td->td_proc->p_pid;
           fli->lk.start = start;
           if (fl->l_len != 0)
                   fli->lk.end = start + fl->l_len - 1;
           else
                   fli->lk.end = INT64_MAX;
           fli->lk.type = fl->l_type;
           fli->lk.pid = td->td_proc->p_pid;
   
           err = fdisp_wait_answ(&fdi);
           fdisp_destroy(&fdi);
   
           if (err == 0 && op == FUSE_GETLK) {
                   flo = fdi.answ;
                   fl->l_type = flo->lk.type;
                   fl->l_whence = SEEK_SET;
                   if (flo->lk.type != F_UNLCK) {
                           fl->l_pid = flo->lk.pid;
                           fl->l_start = flo->lk.start;
                           if (flo->lk.end == INT64_MAX)
                                   fl->l_len = 0;
                           else
                                   fl->l_len = flo->lk.end - flo->lk.start + 1;
                           fl->l_start = flo->lk.start;
                   }
           }
   
   out:
           VOP_UNLOCK(vp);
           return err;
   }
   
   static int
   fuse_vnop_allocate(struct vop_allocate_args *ap)
   {
           struct vnode *vp = ap->a_vp;
           off_t *len = ap->a_len;
           off_t *offset = ap->a_offset;
           struct ucred *cred = ap->a_cred;
           struct fuse_filehandle *fufh;
           struct mount *mp = vnode_mount(vp);
           struct fuse_dispatcher fdi;
           struct fuse_fallocate_in *ffi;
           struct uio io;
           pid_t pid = curthread->td_proc->p_pid;
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           off_t filesize;
           int err;
   
           if (fuse_isdeadfs(vp))
                   return (ENXIO);
   
           switch (vp->v_type) {
           case VFIFO:
                   return (ESPIPE);
           case VLNK:
           case VREG:
                   if (vfs_isrdonly(mp))
                           return (EROFS);
                   break;
           default:
                   return (ENODEV);
           }
   
           if (vfs_isrdonly(mp))
                   return (EROFS);
   
           if (fsess_not_impl(mp, FUSE_FALLOCATE))
                   return (EINVAL);
   
           io.uio_offset = *offset;
           io.uio_resid = *len;
           err = vn_rlimit_fsize(vp, &io, curthread);
           if (err)
                   return (err);
   
           err = fuse_filehandle_getrw(vp, FWRITE, &fufh, cred, pid);
           if (err)
                   return (err);
   
           fuse_vnode_update(vp, FN_MTIMECHANGE | FN_CTIMECHANGE);
   
           err = fuse_vnode_size(vp, &filesize, cred, curthread);
           if (err)
                   return (err);
           fuse_inval_buf_range(vp, filesize, *offset, *offset + *len);
   
           fdisp_init(&fdi, sizeof(*ffi));
           fdisp_make_vp(&fdi, FUSE_FALLOCATE, vp, curthread, cred);
           ffi = fdi.indata;
           ffi->fh = fufh->fh_id;
           ffi->offset = *offset;
           ffi->length = *len;
           ffi->mode = 0;
           err = fdisp_wait_answ(&fdi);
   
           if (err == ENOSYS) {
                   fsess_set_notimpl(mp, FUSE_FALLOCATE);
                   err = EINVAL;
           } else if (err == EOPNOTSUPP) {
                   /*
                    * The file system server does not support FUSE_FALLOCATE with
                    * the supplied mode for this particular file.
                    */
                   err = EINVAL;
           } else if (!err) {
                   *offset += *len;
                   *len = 0;
                   fuse_vnode_undirty_cached_timestamps(vp, false);
                   fuse_internal_clear_suid_on_write(vp, cred, curthread);
                   if (*offset > fvdat->cached_attrs.va_size) {
                           fuse_vnode_setsize(vp, *offset, false);
                           getnanouptime(&fvdat->last_local_modify);
                   }
           }
   
           return (err);
   }
   
   /* {
           struct vnode *a_vp;
           daddr_t a_bn;
           struct bufobj **a_bop;
           daddr_t *a_bnp;
           int *a_runp;
           int *a_runb;
   } */
   static int
   fuse_vnop_bmap(struct vop_bmap_args *ap)
   {
           struct vnode *vp = ap->a_vp;
           struct bufobj **bo = ap->a_bop;
           struct thread *td = curthread;
           struct mount *mp;
           struct fuse_dispatcher fdi;
           struct fuse_bmap_in *fbi;
           struct fuse_bmap_out *fbo;
           struct fuse_data *data;
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           uint64_t biosize;
           off_t fsize;
           daddr_t lbn = ap->a_bn;
           daddr_t *pbn = ap->a_bnp;
           int *runp = ap->a_runp;
           int *runb = ap->a_runb;
           int error = 0;
           int maxrun;
   
           if (fuse_isdeadfs(vp)) {
                   return ENXIO;
           }
   
           mp = vnode_mount(vp);
           data = fuse_get_mpdata(mp);
           biosize = fuse_iosize(vp);
           maxrun = MIN(vp->v_mount->mnt_iosize_max / biosize - 1,
                   data->max_readahead_blocks);
   
           if (bo != NULL)
                   *bo = &vp->v_bufobj;
   
           /*
            * The FUSE_BMAP operation does not include the runp and runb
            * variables, so we must guess.  Report nonzero contiguous runs so
            * cluster_read will combine adjacent reads.  It's worthwhile to reduce
            * upcalls even if we don't know the true physical layout of the file.
            * 
            * FUSE file systems may opt out of read clustering in two ways:
            * * mounting with -onoclusterr
            * * Setting max_readahead <= maxbcachebuf during FUSE_INIT
            */
           if (runb != NULL)
                   *runb = MIN(lbn, maxrun);
           if (runp != NULL && maxrun == 0)
                   *runp = 0;
           else if (runp != NULL) {
                   /*
                    * If the file's size is cached, use that value to calculate
                    * runp, even if the cache is expired.  runp is only advisory,
                    * and the risk of getting it wrong is not worth the cost of
                    * another upcall.
                    */
                   if (fvdat->cached_attrs.va_size != VNOVAL)
                           fsize = fvdat->cached_attrs.va_size;
                   else
                           error = fuse_vnode_size(vp, &fsize, td->td_ucred, td);
                   if (error == 0)
                           *runp = MIN(MAX(0, fsize / (off_t)biosize - lbn - 1),
                                       maxrun);
                   else
                           *runp = 0;
           }
   
           if (fsess_maybe_impl(mp, FUSE_BMAP)) {
                   fdisp_init(&fdi, sizeof(*fbi));
                   fdisp_make_vp(&fdi, FUSE_BMAP, vp, td, td->td_ucred);
                   fbi = fdi.indata;
                   fbi->block = lbn;
                   fbi->blocksize = biosize;
                   error = fdisp_wait_answ(&fdi);
                   if (error == ENOSYS) {
                           fdisp_destroy(&fdi);
                           fsess_set_notimpl(mp, FUSE_BMAP);
                           error = 0;
                   } else {
                           fbo = fdi.answ;
                           if (error == 0 && pbn != NULL)
                                   *pbn = fbo->block;
                           fdisp_destroy(&fdi);
                           return error;
                   }
           }
   
           /* If the daemon doesn't support BMAP, make up a sensible default */
           if (pbn != NULL)
                   *pbn = lbn * btodb(biosize);
           return (error);
   }
   
   /*
       struct vop_close_args {
           struct vnode *a_vp;
           int  a_fflag;
           struct ucred *a_cred;
           struct thread *a_td;
       };
   */
   static int
   fuse_vnop_close(struct vop_close_args *ap)
   {
           struct vnode *vp = ap->a_vp;
           struct ucred *cred = ap->a_cred;
           int fflag = ap->a_fflag;
           struct thread *td = ap->a_td;
           pid_t pid = td->td_proc->p_pid;
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           int err = 0;
   
           if (fuse_isdeadfs(vp))
                   return 0;
           if (vnode_isdir(vp))
                   return 0;
           if (fflag & IO_NDELAY)
                   return 0;
   
           err = fuse_flush(vp, cred, pid, fflag);
           if (err == 0 && (fvdat->flag & FN_ATIMECHANGE)) {
                   struct vattr vap;
   
                   VATTR_NULL(&vap);
                   vap.va_atime = fvdat->cached_attrs.va_atime;
                   err = fuse_internal_setattr(vp, &vap, td, NULL);
           }
           /* TODO: close the file handle, if we're sure it's no longer used */
           if ((fvdat->flag & FN_SIZECHANGE) != 0) {
                   fuse_vnode_savesize(vp, cred, td->td_proc->p_pid);
           }
           return err;
   }
   
   /*
      struct vop_copy_file_range_args {
           struct vop_generic_args a_gen;
           struct vnode *a_invp;
           off_t *a_inoffp;
           struct vnode *a_outvp;
           off_t *a_outoffp;
           size_t *a_lenp;
           unsigned int a_flags;
           struct ucred *a_incred;
           struct ucred *a_outcred;
           struct thread *a_fsizetd;
   }
    */
   static int
   fuse_vnop_copy_file_range(struct vop_copy_file_range_args *ap)
   {
           struct vnode *invp = ap->a_invp;
           struct vnode *outvp = ap->a_outvp;
           struct mount *mp = vnode_mount(invp);
           struct fuse_vnode_data *outfvdat = VTOFUD(outvp);
           struct fuse_dispatcher fdi;
           struct fuse_filehandle *infufh, *outfufh;
           struct fuse_copy_file_range_in *fcfri;
           struct ucred *incred = ap->a_incred;
           struct ucred *outcred = ap->a_outcred;
           struct fuse_write_out *fwo;
           struct thread *td;
           struct uio io;
           off_t outfilesize;
           ssize_t r = 0;
           pid_t pid;
           int err;
   
           if (mp != vnode_mount(outvp))
                   goto fallback;
   
           if (incred->cr_uid != outcred->cr_uid)
                   goto fallback;
   
           if (incred->cr_groups[0] != outcred->cr_groups[0])
                   goto fallback;
   
           if (fsess_not_impl(mp, FUSE_COPY_FILE_RANGE))
                   goto fallback;
   
           if (ap->a_fsizetd == NULL)
                   td = curthread;
           else
                   td = ap->a_fsizetd;
           pid = td->td_proc->p_pid;
   
           /* Lock both vnodes, avoiding risk of deadlock. */
           do {
                   err = vn_lock(outvp, LK_EXCLUSIVE);
                   if (invp == outvp)
                           break;
                   if (err == 0) {
                           err = vn_lock(invp, LK_SHARED | LK_NOWAIT);
                           if (err == 0)
                                   break;
                           VOP_UNLOCK(outvp);
                           err = vn_lock(invp, LK_SHARED);
                           if (err == 0)
                                   VOP_UNLOCK(invp);
                   }
           } while (err == 0);
           if (err != 0)
                   return (err);
   
           err = fuse_filehandle_getrw(invp, FREAD, &infufh, incred, pid);
           if (err)
                   goto unlock;
   
           err = fuse_filehandle_getrw(outvp, FWRITE, &outfufh, outcred, pid);
           if (err)
                   goto unlock;
   
           io.uio_resid = *ap->a_lenp;
           if (ap->a_fsizetd) {
                   io.uio_offset = *ap->a_outoffp;
                   err = vn_rlimit_fsizex(outvp, &io, 0, &r, ap->a_fsizetd);
                   if (err != 0)
                           goto unlock;
           }
   
           err = fuse_vnode_size(outvp, &outfilesize, outcred, curthread);
           if (err)
                   goto unlock;
   
           err = fuse_inval_buf_range(outvp, outfilesize, *ap->a_outoffp,
                   *ap->a_outoffp + io.uio_resid);
           if (err)
                   goto unlock;
   
           fdisp_init(&fdi, sizeof(*fcfri));
           fdisp_make_vp(&fdi, FUSE_COPY_FILE_RANGE, invp, td, incred);
           fcfri = fdi.indata;
           fcfri->fh_in = infufh->fh_id;
           fcfri->off_in = *ap->a_inoffp;
           fcfri->nodeid_out = VTOI(outvp);
           fcfri->fh_out = outfufh->fh_id;
           fcfri->off_out = *ap->a_outoffp;
           fcfri->len = io.uio_resid;
           fcfri->flags = 0;
   
           err = fdisp_wait_answ(&fdi);
           if (err == 0) {
                   fwo = fdi.answ;
                   *ap->a_lenp = fwo->size;
                   *ap->a_inoffp += fwo->size;
                   *ap->a_outoffp += fwo->size;
                   fuse_internal_clear_suid_on_write(outvp, outcred, td);
                   if (*ap->a_outoffp > outfvdat->cached_attrs.va_size) {
                           fuse_vnode_setsize(outvp, *ap->a_outoffp, false);
                           getnanouptime(&outfvdat->last_local_modify);
                   }
                   fuse_vnode_update(invp, FN_ATIMECHANGE);
                   fuse_vnode_update(outvp, FN_MTIMECHANGE | FN_CTIMECHANGE);
           }
           fdisp_destroy(&fdi);
   
   unlock:
           if (invp != outvp)
                   VOP_UNLOCK(invp);
           VOP_UNLOCK(outvp);
   
           if (err == ENOSYS) {
                   fsess_set_notimpl(mp, FUSE_COPY_FILE_RANGE);
   fallback:
                   err = vn_generic_copy_file_range(ap->a_invp, ap->a_inoffp,
                       ap->a_outvp, ap->a_outoffp, ap->a_lenp, ap->a_flags,
                       ap->a_incred, ap->a_outcred, ap->a_fsizetd);
           }
   
           /*
            * No need to call vn_rlimit_fsizex_res before return, since the uio is
            * local.
            */
           return (err);
   }
   
   static void
   fdisp_make_mknod_for_fallback(
           struct fuse_dispatcher *fdip,
           struct componentname *cnp,
           struct vnode *dvp,
           uint64_t parentnid,
           struct thread *td,
           struct ucred *cred,
           mode_t mode,
           enum fuse_opcode *op)
   {
           struct fuse_mknod_in *fmni;
   
           fdisp_init(fdip, sizeof(*fmni) + cnp->cn_namelen + 1);
           *op = FUSE_MKNOD;
           fdisp_make(fdip, *op, vnode_mount(dvp), parentnid, td, cred);
           fmni = fdip->indata;
           fmni->mode = mode;
           fmni->rdev = 0;
           memcpy((char *)fdip->indata + sizeof(*fmni), cnp->cn_nameptr,
               cnp->cn_namelen);
           ((char *)fdip->indata)[sizeof(*fmni) + cnp->cn_namelen] = '\0';
   }
   /*
       struct vnop_create_args {
           struct vnode *a_dvp;
           struct vnode **a_vpp;
           struct componentname *a_cnp;
           struct vattr *a_vap;
       };
   */
   static int
   fuse_vnop_create(struct vop_create_args *ap)
   {
           struct vnode *dvp = ap->a_dvp;
           struct vnode **vpp = ap->a_vpp;
           struct componentname *cnp = ap->a_cnp;
           struct vattr *vap = ap->a_vap;
           struct thread *td = curthread;
           struct ucred *cred = cnp->cn_cred;
   
           struct fuse_data *data;
           struct fuse_create_in *fci;
           struct fuse_entry_out *feo;
          struct fuse_open_out *foo;
          struct fuse_dispatcher fdi, fdi2;
          struct fuse_dispatcher *fdip = &fdi;
          struct fuse_dispatcher *fdip2 = NULL;
  
          int err;
  
          struct mount *mp = vnode_mount(dvp);
          data = fuse_get_mpdata(mp);
          uint64_t parentnid = VTOFUD(dvp)->nid;
          mode_t mode = MAKEIMODE(vap->va_type, vap->va_mode);
          enum fuse_opcode op;
          int flags;
  
          if (fuse_isdeadfs(dvp))
                  return ENXIO;
  
          /* FUSE expects sockets to be created with FUSE_MKNOD */
          if (vap->va_type == VSOCK)
                  return fuse_internal_mknod(dvp, vpp, cnp, vap);
  
          /* 
           * VOP_CREATE doesn't tell us the open(2) flags, so we guess.  Only a
           * writable mode makes sense, and we might as well include readability
           * too.
           */
          flags = O_RDWR;
  
          bzero(&fdi, sizeof(fdi));
  
          if (vap->va_type != VREG)
                  return (EINVAL);
  
          if (fsess_not_impl(mp, FUSE_CREATE) || vap->va_type == VSOCK) {
                  /* Fallback to FUSE_MKNOD/FUSE_OPEN */
                  fdisp_make_mknod_for_fallback(fdip, cnp, dvp, parentnid, td,
                          cred, mode, &op);
          } else {
                  /* Use FUSE_CREATE */
                  size_t insize;
  
                  op = FUSE_CREATE;
                  fdisp_init(fdip, sizeof(*fci) + cnp->cn_namelen + 1);
                  fdisp_make(fdip, op, vnode_mount(dvp), parentnid, td, cred);
                  fci = fdip->indata;
                  fci->mode = mode;
                  fci->flags = O_CREAT | flags;
                  if (fuse_libabi_geq(data, 7, 12)) {
                          insize = sizeof(*fci);
                          fci->umask = td->td_proc->p_pd->pd_cmask;
                  } else {
                          insize = sizeof(struct fuse_open_in);
                  }
  
                  memcpy((char *)fdip->indata + insize, cnp->cn_nameptr,
                      cnp->cn_namelen);
                  ((char *)fdip->indata)[insize + cnp->cn_namelen] = '\0';
          }
  
          err = fdisp_wait_answ(fdip);
  
          if (err) {
                  if (err == ENOSYS && op == FUSE_CREATE) {
                          fsess_set_notimpl(mp, FUSE_CREATE);
                          fdisp_destroy(fdip);
                          fdisp_make_mknod_for_fallback(fdip, cnp, dvp,
                                  parentnid, td, cred, mode, &op);
                          err = fdisp_wait_answ(fdip);
                  }
                  if (err)
                          goto out;
          }
  
          feo = fdip->answ;
  
          if ((err = fuse_internal_checkentry(feo, vap->va_type))) {
                  goto out;
          }
  
          if (op == FUSE_CREATE) {
                  if (fuse_libabi_geq(data, 7, 9))
                          foo = (struct fuse_open_out*)(feo + 1);
                  else
                          foo = (struct fuse_open_out*)((char*)feo +
                                  FUSE_COMPAT_ENTRY_OUT_SIZE);
          } else {
                  /* Issue a separate FUSE_OPEN */
                  struct fuse_open_in *foi;
  
                  fdip2 = &fdi2;
                  fdisp_init(fdip2, sizeof(*foi));
                  fdisp_make(fdip2, FUSE_OPEN, vnode_mount(dvp), feo->nodeid, td,
                          cred);
                  foi = fdip2->indata;
                  foi->flags = flags;
                  err = fdisp_wait_answ(fdip2);
                  if (err)
                          goto out;
                  foo = fdip2->answ;
          }
          err = fuse_vnode_get(mp, feo, feo->nodeid, dvp, vpp, cnp, vap->va_type);
          if (err) {
                  struct fuse_release_in *fri;
                  uint64_t nodeid = feo->nodeid;
                  uint64_t fh_id = foo->fh;
  
                  fdisp_init(fdip, sizeof(*fri));
                  fdisp_make(fdip, FUSE_RELEASE, mp, nodeid, td, cred);
                  fri = fdip->indata;
                  fri->fh = fh_id;
                  fri->flags = flags;
                  fuse_insert_callback(fdip->tick, fuse_internal_forget_callback);
                  fuse_insert_message(fdip->tick, false);
                  goto out;
          }
          ASSERT_VOP_ELOCKED(*vpp, "fuse_vnop_create");
          fuse_internal_cache_attrs(*vpp, &feo->attr, feo->attr_valid,
                  feo->attr_valid_nsec, NULL, true);
  
          fuse_filehandle_init(*vpp, FUFH_RDWR, NULL, td, cred, foo);
          fuse_vnode_open(*vpp, foo->open_flags, td);
          /* 
           * Purge the parent's attribute cache because the daemon should've
           * updated its mtime and ctime
           */
          fuse_vnode_clear_attr_cache(dvp);
          cache_purge_negative(dvp);
  
  out:
          if (fdip2)
                  fdisp_destroy(fdip2);
          fdisp_destroy(fdip);
          return err;
  }
  
  /*
      struct vnop_fdatasync_args {
          struct vop_generic_args a_gen;
          struct vnode * a_vp;
          struct thread * a_td;
      };
  */
  static int
  fuse_vnop_fdatasync(struct vop_fdatasync_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct thread *td = ap->a_td;
          int waitfor = MNT_WAIT;
  
          int err = 0;
  
          if (fuse_isdeadfs(vp)) {
                  return 0;
          }
          if ((err = vop_stdfdatasync_buf(ap)))
                  return err;
  
          return fuse_internal_fsync(vp, td, waitfor, true);
  }
  
  /*
      struct vnop_fsync_args {
          struct vop_generic_args a_gen;
          struct vnode * a_vp;
          int  a_waitfor;
          struct thread * a_td;
      };
  */
  static int
  fuse_vnop_fsync(struct vop_fsync_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct thread *td = ap->a_td;
          int waitfor = ap->a_waitfor;
          int err = 0;
  
          if (fuse_isdeadfs(vp)) {
                  return 0;
          }
          if ((err = vop_stdfsync(ap)))
                  return err;
  
          return fuse_internal_fsync(vp, td, waitfor, false);
  }
  
  /*
      struct vnop_getattr_args {
          struct vnode *a_vp;
          struct vattr *a_vap;
          struct ucred *a_cred;
          struct thread *a_td;
      };
  */
  static int
  fuse_vnop_getattr(struct vop_getattr_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct vattr *vap = ap->a_vap;
          struct ucred *cred = ap->a_cred;
          struct thread *td = curthread;
  
          int err = 0;
          int dataflags;
  
          dataflags = fuse_get_mpdata(vnode_mount(vp))->dataflags;
  
          /* Note that we are not bailing out on a dead file system just yet. */
  
          if (!(dataflags & FSESS_INITED)) {
                  if (!vnode_isvroot(vp)) {
                          fdata_set_dead(fuse_get_mpdata(vnode_mount(vp)));
                          err = ENOTCONN;
                          return err;
                  } else {
                          goto fake;
                  }
          }
          err = fuse_internal_getattr(vp, vap, cred, td);
          if (err == ENOTCONN && vnode_isvroot(vp)) {
                  /* see comment in fuse_vfsop_statfs() */
                  goto fake;
          } else {
                  return err;
          }
  
  fake:
          bzero(vap, sizeof(*vap));
          vap->va_type = vnode_vtype(vp);
  
          return 0;
  }
  
  /*
      struct vnop_inactive_args {
          struct vnode *a_vp;
      };
  */
  static int
  fuse_vnop_inactive(struct vop_inactive_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct thread *td = curthread;
  
          struct fuse_vnode_data *fvdat = VTOFUD(vp);
          struct fuse_filehandle *fufh, *fufh_tmp;
  
          int need_flush = 1;
  
          LIST_FOREACH_SAFE(fufh, &fvdat->handles, next, fufh_tmp) {
                  if (need_flush && vp->v_type == VREG) {
                          if ((VTOFUD(vp)->flag & FN_SIZECHANGE) != 0) {
                                  fuse_vnode_savesize(vp, NULL, 0);
                          }
                          if ((fvdat->flag & FN_REVOKED) != 0)
                                  fuse_io_invalbuf(vp, td);
                          else
                                  fuse_io_flushbuf(vp, MNT_WAIT, td);
                          need_flush = 0;
                  }
                  fuse_filehandle_close(vp, fufh, td, NULL);
          }
  
          if ((fvdat->flag & FN_REVOKED) != 0)
                  vrecycle(vp);
  
          return 0;
  }
  
  /*
      struct vnop_ioctl_args {
          struct vnode *a_vp;
          u_long a_command;
          caddr_t a_data;
          int a_fflag;
          struct ucred *a_cred;
          struct thread *a_td;
      };
  */
  static int
  fuse_vnop_ioctl(struct vop_ioctl_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct mount *mp = vnode_mount(vp);
          struct ucred *cred = ap->a_cred;
          off_t *offp;
          pid_t pid = ap->a_td->td_proc->p_pid;
          int err;
  
          switch (ap->a_command) {
          case FIOSEEKDATA:
          case FIOSEEKHOLE:
                  /* Call FUSE_LSEEK, if we can, or fall back to vop_stdioctl */
                  if (fsess_maybe_impl(mp, FUSE_LSEEK)) {
                          int whence;
  
                          offp = ap->a_data;
                          if (ap->a_command == FIOSEEKDATA)
                                  whence = SEEK_DATA;
                          else
                                  whence = SEEK_HOLE;
  
                          vn_lock(vp, LK_SHARED | LK_RETRY);
                          err = fuse_vnop_do_lseek(vp, ap->a_td, cred, pid, offp,
                              whence);
                          VOP_UNLOCK(vp);
                  }
                  if (fsess_not_impl(mp, FUSE_LSEEK))
                          err = vop_stdioctl(ap);
                  break;
          default:
                  /* TODO: implement FUSE_IOCTL */
                  err = ENOTTY;
                  break;
          }
          return (err);
  }
  
  
  /*
      struct vnop_link_args {
          struct vnode *a_tdvp;
          struct vnode *a_vp;
          struct componentname *a_cnp;
      };
  */
  static int
  fuse_vnop_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 vattr *vap = VTOVA(vp);
  
          struct fuse_dispatcher fdi;
          struct fuse_entry_out *feo;
          struct fuse_link_in fli;
  
          int err;
  
          if (fuse_isdeadfs(vp)) {
                  return ENXIO;
          }
          if (vnode_mount(tdvp) != vnode_mount(vp)) {
                  return EXDEV;
          }
  
          /*
           * This is a seatbelt check to protect naive userspace filesystems from
           * themselves and the limitations of the FUSE IPC protocol.  If a
           * filesystem does not allow attribute caching, assume it is capable of
           * validating that nlink does not overflow.
           */
          if (vap != NULL && vap->va_nlink >= FUSE_LINK_MAX)
                  return EMLINK;
          fli.oldnodeid = VTOI(vp);
  
          fdisp_init(&fdi, 0);
          fuse_internal_newentry_makerequest(vnode_mount(tdvp), VTOI(tdvp), cnp,
              FUSE_LINK, &fli, sizeof(fli), &fdi);
          if ((err = fdisp_wait_answ(&fdi))) {
                  goto out;
          }
          feo = fdi.answ;
  
          if (fli.oldnodeid != feo->nodeid) {
                  struct fuse_data *data = fuse_get_mpdata(vnode_mount(vp));
                  fuse_warn(data, FSESS_WARN_ILLEGAL_INODE,
                          "Assigned wrong inode for a hard link.");
                  fuse_vnode_clear_attr_cache(vp);
                  fuse_vnode_clear_attr_cache(tdvp);
                  err = EIO;
                  goto out;
          }
  
          err = fuse_internal_checkentry(feo, vnode_vtype(vp));
          if (!err) {
                  /* 
                   * Purge the parent's attribute cache because the daemon
                   * should've updated its mtime and ctime
                   */
                  fuse_vnode_clear_attr_cache(tdvp);
                  fuse_internal_cache_attrs(vp, &feo->attr, feo->attr_valid,
                          feo->attr_valid_nsec, NULL, true);
          }
  out:
          fdisp_destroy(&fdi);
          return err;
  }
  
  struct fuse_lookup_alloc_arg {
          struct fuse_entry_out *feo;
          struct componentname *cnp;
          uint64_t nid;
          enum vtype vtyp;
  };
  
  /* Callback for vn_get_ino */
  static int
  fuse_lookup_alloc(struct mount *mp, void *arg, int lkflags, struct vnode **vpp)
  {
          struct fuse_lookup_alloc_arg *flaa = arg;
  
          return fuse_vnode_get(mp, flaa->feo, flaa->nid, NULL, vpp, flaa->cnp,
                  flaa->vtyp);
  }
  
  SDT_PROBE_DEFINE3(fusefs, , vnops, cache_lookup,
          "int", "struct timespec*", "struct timespec*");
  /*
      struct vnop_lookup_args {
          struct vnodeop_desc *a_desc;
          struct vnode *a_dvp;
          struct vnode **a_vpp;
          struct componentname *a_cnp;
      };
  */
  int
  fuse_vnop_lookup(struct vop_lookup_args *ap)
  {
          struct vnode *dvp = ap->a_dvp;
          struct vnode **vpp = ap->a_vpp;
          struct componentname *cnp = ap->a_cnp;
          struct thread *td = curthread;
          struct ucred *cred = cnp->cn_cred;
          struct timespec now;
  
          int nameiop = cnp->cn_nameiop;
          int flags = cnp->cn_flags;
          int islastcn = flags & ISLASTCN;
          struct mount *mp = vnode_mount(dvp);
          struct fuse_data *data = fuse_get_mpdata(mp);
          int default_permissions = data->dataflags & FSESS_DEFAULT_PERMISSIONS;
          bool is_dot;
  
          int err = 0;
          int lookup_err = 0;
          struct vnode *vp = NULL;
  
          struct fuse_dispatcher fdi;
          bool did_lookup = false;
          struct fuse_entry_out *feo = NULL;
          enum vtype vtyp;        /* vnode type of target */
  
          uint64_t nid;
  
          if (fuse_isdeadfs(dvp)) {
                  *vpp = NULL;
                  return ENXIO;
          }
          if (!vnode_isdir(dvp))
                  return ENOTDIR;
  
          if (islastcn && vfs_isrdonly(mp) && (nameiop != LOOKUP))
                  return EROFS;
  
          if ((cnp->cn_flags & NOEXECCHECK) != 0)
                  cnp->cn_flags &= ~NOEXECCHECK;
          else if ((err = fuse_internal_access(dvp, VEXEC, td, cred)))
                  return err;
  
          is_dot = cnp->cn_namelen == 1 && *(cnp->cn_nameptr) == '.';
          if ((flags & ISDOTDOT) && !(data->dataflags & FSESS_EXPORT_SUPPORT))
          {
                  if (!(VTOFUD(dvp)->flag & FN_PARENT_NID)) {
                          /*
                           * Since the file system doesn't support ".." lookups,
                           * we have no way to find this entry.
                           */
                          return ESTALE;
                  }
                  nid = VTOFUD(dvp)->parent_nid;
                  if (nid == 0)
                          return ENOENT;
                  /* .. is obviously a directory */
                  vtyp = VDIR;
          } else if (is_dot) {
                  nid = VTOI(dvp);
                  /* . is obviously a directory */
                  vtyp = VDIR;
          } else {
                  struct timespec timeout;
                  int ncpticks; /* here to accommodate for API contract */
  
                  err = cache_lookup(dvp, vpp, cnp, &timeout, &ncpticks);
                  getnanouptime(&now);
                  SDT_PROBE3(fusefs, , vnops, cache_lookup, err, &timeout, &now);
                  switch (err) {
                  case -1:                /* positive match */
                          if (timespeccmp(&timeout, &now, >)) {
                                  counter_u64_add(fuse_lookup_cache_hits, 1);
                          } else {
                                  /* Cache timeout */
                                  counter_u64_add(fuse_lookup_cache_misses, 1);
                                  bintime_clear(
                                          &VTOFUD(*vpp)->entry_cache_timeout);
                                  cache_purge(*vpp);
                                  if (dvp != *vpp)
                                          vput(*vpp);
                                  else 
                                          vrele(*vpp);
                                  *vpp = NULL;
                                  break;
                          }
                          return 0;
  
                  case 0:         /* no match in cache */
                          counter_u64_add(fuse_lookup_cache_misses, 1);
                          break;
  
                  case ENOENT:            /* negative match */
                          if (timespeccmp(&timeout, &now, <=)) {
                                  /* Cache timeout */
                                  cache_purge_negative(dvp);
                                  break;
                          }
                          /* fall through */
                  default:
                          return err;
                  }
  
                  fdisp_init(&fdi, cnp->cn_namelen + 1);
                  fdisp_make(&fdi, FUSE_LOOKUP, mp, VTOI(dvp), td, cred);
  
                  memcpy(fdi.indata, cnp->cn_nameptr, cnp->cn_namelen);
                  ((char *)fdi.indata)[cnp->cn_namelen] = '\0';
                  lookup_err = fdisp_wait_answ(&fdi);
                  did_lookup = true;
  
                  if (!lookup_err) {
                          /* lookup call succeeded */
                          feo = (struct fuse_entry_out *)fdi.answ;
                          nid = feo->nodeid;
                          if (nid == 0) {
                                  /* zero nodeid means ENOENT and cache it */
                                  struct timespec timeout;
  
                                  fdi.answ_stat = ENOENT;
                                  lookup_err = ENOENT;
                                  if (cnp->cn_flags & MAKEENTRY) {
                                          fuse_validity_2_timespec(feo, &timeout);
                                          /* Use the same entry_time for .. as for
                                           * the file itself.  That doesn't honor
                                           * exactly what the fuse server tells
                                           * us, but to do otherwise would require
                                           * another cache lookup at this point.
                                           */
                                          struct timespec *dtsp = NULL;
                                          cache_enter_time(dvp, *vpp, cnp,
                                                  &timeout, dtsp);
                                  }
                          }
                          vtyp = IFTOVT(feo->attr.mode);
                  }
                  if (lookup_err && (!fdi.answ_stat || lookup_err != ENOENT)) {
                          fdisp_destroy(&fdi);
                          return lookup_err;
                  }
          }
          /* lookup_err, if non-zero, must be ENOENT at this point */
  
          if (lookup_err) {
                  /* Entry not found */
                  if ((nameiop == CREATE || nameiop == RENAME) && islastcn) {
                          if (default_permissions)
                                  err = fuse_internal_access(dvp, VWRITE, td,
                                      cred);
                          else
                                  err = 0;
                          if (!err) {
                                  err = EJUSTRETURN;
                          }
                  } else {
                          err = ENOENT;
                  }
          } else {
                  /* Entry was found */
                  if (flags & ISDOTDOT) {
                          struct fuse_lookup_alloc_arg flaa;
  
                          flaa.nid = nid;
                          flaa.feo = feo;
                          flaa.cnp = cnp;
                          flaa.vtyp = vtyp;
                          err = vn_vget_ino_gen(dvp, fuse_lookup_alloc, &flaa, 0,
                                  &vp);
                          *vpp = vp;
                  } else if (nid == VTOI(dvp)) {
                          if (is_dot) {
                                  vref(dvp);
                                  *vpp = dvp;
                          } else {
                                  fuse_warn(fuse_get_mpdata(mp),
                                      FSESS_WARN_ILLEGAL_INODE,
                                      "Assigned same inode to both parent and "
                                      "child.");
                                  err = EIO;
                          }
  
                  } else {
                          struct fuse_vnode_data *fvdat;
  
                          err = fuse_vnode_get(vnode_mount(dvp), feo, nid, dvp,
                              &vp, cnp, vtyp);
                          if (err)
                                  goto out;
                          *vpp = vp;
                          fvdat = VTOFUD(vp);
  
                          MPASS(feo != NULL);
                          if (timespeccmp(&now, &fvdat->last_local_modify, >)) {
                                  /*
                                   * Attributes from the server are definitely
                                   * newer than the last attributes we sent to
                                   * the server, so cache them.
                                   */
                                  fuse_internal_cache_attrs(*vpp, &feo->attr,
                                          feo->attr_valid, feo->attr_valid_nsec,
                                          NULL, true);
                          }
                          fuse_validity_2_bintime(feo->entry_valid,
                                  feo->entry_valid_nsec,
                                  &fvdat->entry_cache_timeout);
  
                          if ((nameiop == DELETE || nameiop == RENAME) &&
                                  islastcn && default_permissions)
                          {
                                  struct vattr dvattr;
  
                                  err = fuse_internal_access(dvp, VWRITE, td,
                                          cred);
                                  if (err != 0)
                                          goto out;
                                  /* 
                                   * if the parent's sticky bit is set, check
                                   * whether we're allowed to remove the file.
                                   * Need to figure out the vnode locking to make
                                   * this work.
                                   */
                                  fuse_internal_getattr(dvp, &dvattr, cred, td);
                                  if ((dvattr.va_mode & S_ISTXT) &&
                                          fuse_internal_access(dvp, VADMIN, td,
                                                  cred) &&
                                          fuse_internal_access(*vpp, VADMIN, td,
                                                  cred)) {
                                          err = EPERM;
                                          goto out;
                                  }
                          }
                  }
          }
  out:
          if (err) {
                  if (vp != NULL && dvp != vp)
                          vput(vp);
                  else if (vp != NULL)
                          vrele(vp);
                  *vpp = NULL;
          }
          if (did_lookup)
                  fdisp_destroy(&fdi);
  
          return err;
  }
  
  /*
      struct vnop_mkdir_args {
          struct vnode *a_dvp;
          struct vnode **a_vpp;
          struct componentname *a_cnp;
          struct vattr *a_vap;
      };
  */
  static int
  fuse_vnop_mkdir(struct vop_mkdir_args *ap)
  {
          struct vnode *dvp = ap->a_dvp;
          struct vnode **vpp = ap->a_vpp;
          struct componentname *cnp = ap->a_cnp;
          struct vattr *vap = ap->a_vap;
  
          struct fuse_mkdir_in fmdi;
  
          if (fuse_isdeadfs(dvp)) {
                  return ENXIO;
          }
          fmdi.mode = MAKEIMODE(vap->va_type, vap->va_mode);
          fmdi.umask = curthread->td_proc->p_pd->pd_cmask;
  
          return (fuse_internal_newentry(dvp, vpp, cnp, FUSE_MKDIR, &fmdi,
              sizeof(fmdi), VDIR));
  }
  
  /*
      struct vnop_mknod_args {
          struct vnode *a_dvp;
          struct vnode **a_vpp;
          struct componentname *a_cnp;
          struct vattr *a_vap;
      };
  */
  static int
  fuse_vnop_mknod(struct vop_mknod_args *ap)
  {
  
          struct vnode *dvp = ap->a_dvp;
          struct vnode **vpp = ap->a_vpp;
          struct componentname *cnp = ap->a_cnp;
          struct vattr *vap = ap->a_vap;
  
          if (fuse_isdeadfs(dvp))
                  return ENXIO;
  
          return fuse_internal_mknod(dvp, vpp, cnp, vap);
  }
  
  /*
      struct vop_open_args {
          struct vnode *a_vp;
          int  a_mode;
          struct ucred *a_cred;
          struct thread *a_td;
          int a_fdidx; / struct file *a_fp;
      };
  */
  static int
  fuse_vnop_open(struct vop_open_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          int a_mode = ap->a_mode;
          struct thread *td = ap->a_td;
          struct ucred *cred = ap->a_cred;
          pid_t pid = td->td_proc->p_pid;
  
          if (fuse_isdeadfs(vp))
                  return ENXIO;
          if (vp->v_type == VCHR || vp->v_type == VBLK || vp->v_type == VFIFO)
                  return (EOPNOTSUPP);
          if ((a_mode & (FREAD | FWRITE | FEXEC)) == 0)
                  return EINVAL;
  
          if (fuse_filehandle_validrw(vp, a_mode, cred, pid)) {
                  fuse_vnode_open(vp, 0, td);
                  return 0;
          }
  
          return fuse_filehandle_open(vp, a_mode, NULL, td, cred);
  }
  
  static int
  fuse_vnop_pathconf(struct vop_pathconf_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct mount *mp;
  
          switch (ap->a_name) {
          case _PC_FILESIZEBITS:
                  *ap->a_retval = 64;
                  return (0);
          case _PC_NAME_MAX:
                  *ap->a_retval = NAME_MAX;
                  return (0);
          case _PC_LINK_MAX:
                  *ap->a_retval = MIN(LONG_MAX, FUSE_LINK_MAX);
                  return (0);
          case _PC_SYMLINK_MAX:
                  *ap->a_retval = MAXPATHLEN;
                  return (0);
          case _PC_NO_TRUNC:
                  *ap->a_retval = 1;
                  return (0);
          case _PC_MIN_HOLE_SIZE:
                  /*
                   * The FUSE protocol provides no mechanism for a server to
                   * report _PC_MIN_HOLE_SIZE.  It's a protocol bug.  Instead,
                   * return EINVAL if the server does not support FUSE_LSEEK, or
                   * 1 if it does.
                   */
                  mp = vnode_mount(vp);
                  if (!fsess_is_impl(mp, FUSE_LSEEK) &&
                      !fsess_not_impl(mp, FUSE_LSEEK)) {
                          off_t offset = 0;
  
                          /* Issue a FUSE_LSEEK to find out if it's implemented */
                          fuse_vnop_do_lseek(vp, curthread, curthread->td_ucred,
                              curthread->td_proc->p_pid, &offset, SEEK_DATA);
                  }
  
                  if (fsess_is_impl(mp, FUSE_LSEEK)) {
                          *ap->a_retval = 1;
                          return (0);
                  } else {
                          /*
                           * Probably FUSE_LSEEK is not implemented.  It might
                           * be, if the FUSE_LSEEK above returned an error like
                           * EACCES, but in that case we can't tell, so it's
                           * safest to report EINVAL anyway.
                           */
                          return (EINVAL);
                  }
          default:
                  return (vop_stdpathconf(ap));
          }
  }
  
  SDT_PROBE_DEFINE3(fusefs, , vnops, filehandles_closed, "struct vnode*",
      "struct uio*", "struct ucred*");
  /*
      struct vnop_read_args {
          struct vnode *a_vp;
          struct uio *a_uio;
          int  a_ioflag;
          struct ucred *a_cred;
      };
  */
  static int
  fuse_vnop_read(struct vop_read_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct uio *uio = ap->a_uio;
          int ioflag = ap->a_ioflag;
          struct ucred *cred = ap->a_cred;
          pid_t pid = curthread->td_proc->p_pid;
          struct fuse_filehandle *fufh;
          int err;
          bool closefufh = false, directio;
  
          MPASS(vp->v_type == VREG || vp->v_type == VDIR);
  
          if (fuse_isdeadfs(vp)) {
                  return ENXIO;
          }
  
          if (VTOFUD(vp)->flag & FN_DIRECTIO) {
                  ioflag |= IO_DIRECT;
          }
  
          err = fuse_filehandle_getrw(vp, FREAD, &fufh, cred, pid);
          if (err == EBADF && vnode_mount(vp)->mnt_flag & MNT_EXPORTED) {
                  /*
                   * nfsd will do I/O without first doing VOP_OPEN.  We
                   * must implicitly open the file here
                   */
                  err = fuse_filehandle_open(vp, FREAD, &fufh, curthread, cred);
                  closefufh = true;
          }
          if (err) {
                  SDT_PROBE3(fusefs, , vnops, filehandles_closed, vp, uio, cred);
                  return err;
          }
  
          /*
           * Ideally, when the daemon asks for direct io at open time, the
           * standard file flag should be set according to this, so that would
           * just change the default mode, which later on could be changed via
           * fcntl(2).
           * But this doesn't work, the O_DIRECT flag gets cleared at some point
           * (don't know where). So to make any use of the Fuse direct_io option,
           * we hardwire it into the file's private data (similarly to Linux,
           * btw.).
           */
          directio = (ioflag & IO_DIRECT) || !fsess_opt_datacache(vnode_mount(vp));
  
          fuse_vnode_update(vp, FN_ATIMECHANGE);
          if (directio) {
                  SDT_PROBE2(fusefs, , vnops, trace, 1, "direct read of vnode");
                  err = fuse_read_directbackend(vp, uio, cred, fufh);
          } else {
                  SDT_PROBE2(fusefs, , vnops, trace, 1, "buffered read of vnode");
                  err = fuse_read_biobackend(vp, uio, ioflag, cred, fufh, pid);
          }
  
          if (closefufh)
                  fuse_filehandle_close(vp, fufh, curthread, cred);
  
          return (err);
  }
  
  /*
      struct vnop_readdir_args {
          struct vnode *a_vp;
          struct uio *a_uio;
          struct ucred *a_cred;
          int *a_eofflag;
          int *a_ncookies;
          uint64_t **a_cookies;
      };
  */
  static int
  fuse_vnop_readdir(struct vop_readdir_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct uio *uio = ap->a_uio;
          struct ucred *cred = ap->a_cred;
          struct fuse_filehandle *fufh = NULL;
          struct mount *mp = vnode_mount(vp);
          struct fuse_iov cookediov;
          int err = 0;
          uint64_t *cookies;
          ssize_t tresid;
          int ncookies;
          bool closefufh = false;
          pid_t pid = curthread->td_proc->p_pid;
  
          if (ap->a_eofflag)
                  *ap->a_eofflag = 0;
          if (fuse_isdeadfs(vp)) {
                  return ENXIO;
          }
          if (                            /* XXXIP ((uio_iovcnt(uio) > 1)) || */
              (uio_resid(uio) < sizeof(struct dirent))) {
                  return EINVAL;
          }
  
          tresid = uio->uio_resid;
          err = fuse_filehandle_get_dir(vp, &fufh, cred, pid);
          if (err == EBADF && mp->mnt_flag & MNT_EXPORTED) {
                  KASSERT(fuse_get_mpdata(mp)->dataflags
                                  & FSESS_NO_OPENDIR_SUPPORT,
                          ("FUSE file systems that don't set "
                           "FUSE_NO_OPENDIR_SUPPORT should not be exported"));
                  /* 
                   * nfsd will do VOP_READDIR without first doing VOP_OPEN.  We
                   * must implicitly open the directory here.
                   */
                  err = fuse_filehandle_open(vp, FREAD, &fufh, curthread, cred);
                  closefufh = true;
          }
          if (err)
                  return (err);
          if (ap->a_ncookies != NULL) {
                  ncookies = uio->uio_resid /
                          (offsetof(struct dirent, d_name) + 4) + 1;
                  cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK);
                  *ap->a_ncookies = ncookies;
                  *ap->a_cookies = cookies;
          } else {
                  ncookies = 0;
                  cookies = NULL;
          }
  #define DIRCOOKEDSIZE FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + MAXNAMLEN + 1)
          fiov_init(&cookediov, DIRCOOKEDSIZE);
  
          err = fuse_internal_readdir(vp, uio, fufh, &cookediov,
                  &ncookies, cookies);
  
          fiov_teardown(&cookediov);
          if (closefufh)
                  fuse_filehandle_close(vp, fufh, curthread, cred);
  
          if (ap->a_ncookies != NULL) {
                  if (err == 0) {
                          *ap->a_ncookies -= ncookies;
                  } else {
                          free(*ap->a_cookies, M_TEMP);
                          *ap->a_ncookies = 0;
                          *ap->a_cookies = NULL;
                  }
          }
          if (err == 0 && tresid == uio->uio_resid)
                  *ap->a_eofflag = 1;
  
          return err;
  }
  
  /*
      struct vnop_readlink_args {
          struct vnode *a_vp;
          struct uio *a_uio;
          struct ucred *a_cred;
      };
  */
  static int
  fuse_vnop_readlink(struct vop_readlink_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct uio *uio = ap->a_uio;
          struct ucred *cred = ap->a_cred;
  
          struct fuse_dispatcher fdi;
          int err;
  
          if (fuse_isdeadfs(vp)) {
                  return ENXIO;
          }
          if (!vnode_islnk(vp)) {
                  return EINVAL;
          }
          fdisp_init(&fdi, 0);
          err = fdisp_simple_putget_vp(&fdi, FUSE_READLINK, vp, curthread, cred);
          if (err) {
                  goto out;
          }
          if (((char *)fdi.answ)[0] == '/' &&
              fuse_get_mpdata(vnode_mount(vp))->dataflags & FSESS_PUSH_SYMLINKS_IN) {
                  char *mpth = vnode_mount(vp)->mnt_stat.f_mntonname;
  
                  err = uiomove(mpth, strlen(mpth), uio);
          }
          if (!err) {
                  err = uiomove(fdi.answ, fdi.iosize, uio);
          }
  out:
          fdisp_destroy(&fdi);
          return err;
  }
  
  /*
      struct vnop_reclaim_args {
          struct vnode *a_vp;
      };
  */
  static int
  fuse_vnop_reclaim(struct vop_reclaim_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct thread *td = curthread;
          struct fuse_vnode_data *fvdat = VTOFUD(vp);
          struct fuse_filehandle *fufh, *fufh_tmp;
  
          if (!fvdat) {
                  panic("FUSE: no vnode data during recycling");
          }
          LIST_FOREACH_SAFE(fufh, &fvdat->handles, next, fufh_tmp) {
                  printf("FUSE: vnode being reclaimed with open fufh "
                          "(type=%#x)", fufh->fufh_type);
                  fuse_filehandle_close(vp, fufh, td, NULL);
          }
  
          if (VTOI(vp) == 1) {
                  /*
                   * Don't send FUSE_FORGET for the root inode, because
                   * we never send FUSE_LOOKUP for it (see
                   * fuse_vfsop_root) and we don't want the server to see
                   * mismatched lookup counts.
                   */
                  struct fuse_data *data;
                  struct vnode *vroot;
  
                  data = fuse_get_mpdata(vnode_mount(vp));
                  FUSE_LOCK();
                  vroot = data->vroot;
                  data->vroot = NULL;
                  FUSE_UNLOCK();
                  if (vroot)
                          vrele(vroot);
          } else if (!fuse_isdeadfs(vp) && fvdat->nlookup > 0) {
                  fuse_internal_forget_send(vnode_mount(vp), td, NULL, VTOI(vp),
                      fvdat->nlookup);
          }
          cache_purge(vp);
          vfs_hash_remove(vp);
          fuse_vnode_destroy(vp);
  
          return 0;
  }
  
  /*
      struct vnop_remove_args {
          struct vnode *a_dvp;
          struct vnode *a_vp;
          struct componentname *a_cnp;
      };
  */
  static int
  fuse_vnop_remove(struct vop_remove_args *ap)
  {
          struct vnode *dvp = ap->a_dvp;
          struct vnode *vp = ap->a_vp;
          struct componentname *cnp = ap->a_cnp;
  
          int err;
  
          if (fuse_isdeadfs(vp)) {
                  return ENXIO;
          }
          if (vnode_isdir(vp)) {
                  return EPERM;
          }
  
          err = fuse_internal_remove(dvp, vp, cnp, FUSE_UNLINK);
  
          return err;
  }
  
  /*
      struct vnop_rename_args {
          struct vnode *a_fdvp;
          struct vnode *a_fvp;
          struct componentname *a_fcnp;
          struct vnode *a_tdvp;
          struct vnode *a_tvp;
          struct componentname *a_tcnp;
      };
  */
  static int
  fuse_vnop_rename(struct vop_rename_args *ap)
  {
          struct vnode *fdvp = ap->a_fdvp;
          struct vnode *fvp = ap->a_fvp;
          struct componentname *fcnp = ap->a_fcnp;
          struct vnode *tdvp = ap->a_tdvp;
          struct vnode *tvp = ap->a_tvp;
          struct componentname *tcnp = ap->a_tcnp;
          struct fuse_data *data;
          bool newparent = fdvp != tdvp;
          bool isdir = fvp->v_type == VDIR;
          int err = 0;
  
          if (fuse_isdeadfs(fdvp)) {
                  return ENXIO;
          }
          if (fvp->v_mount != tdvp->v_mount ||
              (tvp && fvp->v_mount != tvp->v_mount)) {
                  SDT_PROBE2(fusefs, , vnops, trace, 1, "cross-device rename");
                  err = EXDEV;
                  goto out;
          }
          cache_purge(fvp);
  
          /*
           * FUSE library is expected to check if target directory is not
           * under the source directory in the file system tree.
           * Linux performs this check at VFS level.
           */
          /* 
           * If source is a directory, and it will get a new parent, user must
           * have write permission to it, so ".." can be modified.
           */
          data = fuse_get_mpdata(vnode_mount(tdvp));
          if (data->dataflags & FSESS_DEFAULT_PERMISSIONS && isdir && newparent) {
                  err = fuse_internal_access(fvp, VWRITE,
                          curthread, tcnp->cn_cred);
                  if (err)
                          goto out;
          }
          sx_xlock(&data->rename_lock);
          err = fuse_internal_rename(fdvp, fcnp, tdvp, tcnp);
          if (err == 0) {
                  if (tdvp != fdvp)
                          fuse_vnode_setparent(fvp, tdvp);
                  if (tvp != NULL)
                          fuse_vnode_setparent(tvp, NULL);
          }
          sx_unlock(&data->rename_lock);
  
          if (tvp != NULL && tvp != fvp) {
                  cache_purge(tvp);
          }
          if (vnode_isdir(fvp)) {
                  if (((tvp != NULL) && vnode_isdir(tvp)) || vnode_isdir(fvp)) {
                          cache_purge(tdvp);
                  }
                  cache_purge(fdvp);
          }
  out:
          if (tdvp == tvp) {
                  vrele(tdvp);
          } else {
                  vput(tdvp);
          }
          if (tvp != NULL) {
                  vput(tvp);
          }
          vrele(fdvp);
          vrele(fvp);
  
          return err;
  }
  
  /*
      struct vnop_rmdir_args {
              struct vnode *a_dvp;
              struct vnode *a_vp;
              struct componentname *a_cnp;
      } *ap;
  */
  static int
  fuse_vnop_rmdir(struct vop_rmdir_args *ap)
  {
          struct vnode *dvp = ap->a_dvp;
          struct vnode *vp = ap->a_vp;
  
          int err;
  
          if (fuse_isdeadfs(vp)) {
                  return ENXIO;
          }
          if (VTOFUD(vp) == VTOFUD(dvp)) {
                  return EINVAL;
          }
          err = fuse_internal_remove(dvp, vp, ap->a_cnp, FUSE_RMDIR);
  
          return err;
  }
  
  /*
      struct vnop_setattr_args {
          struct vnode *a_vp;
          struct vattr *a_vap;
          struct ucred *a_cred;
          struct thread *a_td;
      };
  */
  static int
  fuse_vnop_setattr(struct vop_setattr_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct vattr *vap = ap->a_vap;
          struct ucred *cred = ap->a_cred;
          struct thread *td = curthread;
          struct mount *mp;
          struct fuse_data *data;
          struct vattr old_va;
          int dataflags;
          int err = 0, err2;
          accmode_t accmode = 0;
          bool checkperm;
          bool drop_suid = false;
          gid_t cr_gid;
  
          mp = vnode_mount(vp);
          data = fuse_get_mpdata(mp);
          dataflags = data->dataflags;
          checkperm = dataflags & FSESS_DEFAULT_PERMISSIONS;
          if (cred->cr_ngroups > 0)
                  cr_gid = cred->cr_groups[0];
          else
                  cr_gid = 0;
  
          if (fuse_isdeadfs(vp)) {
                  return ENXIO;
          }
  
          if (vap->va_uid != (uid_t)VNOVAL) {
                  if (checkperm) {
                          /* Only root may change a file's owner */
                          err = priv_check_cred(cred, PRIV_VFS_CHOWN);
                          if (err) {
                                  /* As a special case, allow the null chown */
                                  err2 = fuse_internal_getattr(vp, &old_va, cred,
                                          td);
                                  if (err2)
                                          return (err2);
                                  if (vap->va_uid != old_va.va_uid)
                                          return err;
                                  else
                                          accmode |= VADMIN;
                                  drop_suid = true;
                          } else
                                  accmode |= VADMIN;
                  } else
                          accmode |= VADMIN;
          }
          if (vap->va_gid != (gid_t)VNOVAL) {
                  if (checkperm && priv_check_cred(cred, PRIV_VFS_CHOWN))
                          drop_suid = true;
                  if (checkperm && !groupmember(vap->va_gid, cred))
                  {
                          /*
                           * Non-root users may only chgrp to one of their own
                           * groups 
                           */
                          err = priv_check_cred(cred, PRIV_VFS_CHOWN);
                          if (err) {
                                  /* As a special case, allow the null chgrp */
                                  err2 = fuse_internal_getattr(vp, &old_va, cred,
                                          td);
                                  if (err2)
                                          return (err2);
                                  if (vap->va_gid != old_va.va_gid)
                                          return err;
                                  accmode |= VADMIN;
                          } else
                                  accmode |= VADMIN;
                  } else
                          accmode |= VADMIN;
          }
          if (vap->va_size != VNOVAL) {
                  switch (vp->v_type) {
                  case VDIR:
                          return (EISDIR);
                  case VLNK:
                  case VREG:
                          if (vfs_isrdonly(mp))
                                  return (EROFS);
                          err = vn_rlimit_trunc(vap->va_size, td);
                          if (err)
                                  return (err);
                          break;
                  default:
                          /*
                           * According to POSIX, the result is unspecified
                           * for file types other than regular files,
                           * directories and shared memory objects.  We
                           * don't support shared memory objects in the file
                           * system, and have dubious support for truncating
                           * symlinks.  Just ignore the request in other cases.
                           */
                          return (0);
                  }
                  /* Don't set accmode.  Permission to trunc is checked upstack */
          }
          if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
                  if (vap->va_vaflags & VA_UTIMES_NULL)
                          accmode |= VWRITE;
                  else
                          accmode |= VADMIN;
          }
          if (drop_suid) {
                  if (vap->va_mode != (mode_t)VNOVAL)
                          vap->va_mode &= ~(S_ISUID | S_ISGID);
                  else {
                          err = fuse_internal_getattr(vp, &old_va, cred, td);
                          if (err)
                                  return (err);
                          vap->va_mode = old_va.va_mode & ~(S_ISUID | S_ISGID);
                  }
          }
          if (vap->va_mode != (mode_t)VNOVAL) {
                  /* Only root may set the sticky bit on non-directories */
                  if (checkperm && vp->v_type != VDIR && (vap->va_mode & S_ISTXT)
                      && priv_check_cred(cred, PRIV_VFS_STICKYFILE))
                          return EFTYPE;
                  if (checkperm && (vap->va_mode & S_ISGID)) {
                          err = fuse_internal_getattr(vp, &old_va, cred, td);
                          if (err)
                                  return (err);
                          if (!groupmember(old_va.va_gid, cred)) {
                                  err = priv_check_cred(cred, PRIV_VFS_SETGID);
                                  if (err)
                                          return (err);
                          }
                  }
                  accmode |= VADMIN;
          }
  
          if (vfs_isrdonly(mp))
                  return EROFS;
  
          if (checkperm) {
                  err = fuse_internal_access(vp, accmode, td, cred);
          } else {
                  err = 0;
          }
          if (err)
                  return err;
          else
                  return fuse_internal_setattr(vp, vap, td, cred);
  }
  
  /*
      struct vnop_strategy_args {
          struct vnode *a_vp;
          struct buf *a_bp;
      };
  */
  static int
  fuse_vnop_strategy(struct vop_strategy_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct buf *bp = ap->a_bp;
  
          if (!vp || fuse_isdeadfs(vp)) {
                  bp->b_ioflags |= BIO_ERROR;
                  bp->b_error = ENXIO;
                  bufdone(bp);
                  return 0;
          }
  
          /*
           * VOP_STRATEGY always returns zero and signals error via bp->b_ioflags.
           * fuse_io_strategy sets bp's error fields
           */
          (void)fuse_io_strategy(vp, bp);
  
          return 0;
  }
  
  /*
      struct vnop_symlink_args {
          struct vnode *a_dvp;
          struct vnode **a_vpp;
          struct componentname *a_cnp;
          struct vattr *a_vap;
          char *a_target;
      };
  */
  static int
  fuse_vnop_symlink(struct vop_symlink_args *ap)
  {
          struct vnode *dvp = ap->a_dvp;
          struct vnode **vpp = ap->a_vpp;
          struct componentname *cnp = ap->a_cnp;
          const char *target = ap->a_target;
  
          struct fuse_dispatcher fdi;
  
          int err;
          size_t len;
  
          if (fuse_isdeadfs(dvp)) {
                  return ENXIO;
          }
          /*
           * Unlike the other creator type calls, here we have to create a message
           * where the name of the new entry comes first, and the data describing
           * the entry comes second.
           * Hence we can't rely on our handy fuse_internal_newentry() routine,
           * but put together the message manually and just call the core part.
           */
  
          len = strlen(target) + 1;
          fdisp_init(&fdi, len + cnp->cn_namelen + 1);
          fdisp_make_vp(&fdi, FUSE_SYMLINK, dvp, curthread, NULL);
  
          memcpy(fdi.indata, cnp->cn_nameptr, cnp->cn_namelen);
          ((char *)fdi.indata)[cnp->cn_namelen] = '\0';
          memcpy((char *)fdi.indata + cnp->cn_namelen + 1, target, len);
  
          err = fuse_internal_newentry_core(dvp, vpp, cnp, VLNK, &fdi);
          fdisp_destroy(&fdi);
          return err;
  }
  
  /*
      struct vnop_write_args {
          struct vnode *a_vp;
          struct uio *a_uio;
          int  a_ioflag;
          struct ucred *a_cred;
      };
  */
  static int
  fuse_vnop_write(struct vop_write_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct uio *uio = ap->a_uio;
          int ioflag = ap->a_ioflag;
          struct ucred *cred = ap->a_cred;
          pid_t pid = curthread->td_proc->p_pid;
          struct fuse_filehandle *fufh;
          int err;
          bool closefufh = false, directio;
  
          MPASS(vp->v_type == VREG || vp->v_type == VDIR);
  
          if (fuse_isdeadfs(vp)) {
                  return ENXIO;
          }
  
          if (VTOFUD(vp)->flag & FN_DIRECTIO) {
                  ioflag |= IO_DIRECT;
          }
  
          err = fuse_filehandle_getrw(vp, FWRITE, &fufh, cred, pid);
          if (err == EBADF && vnode_mount(vp)->mnt_flag & MNT_EXPORTED) {
                  /*
                   * nfsd will do I/O without first doing VOP_OPEN.  We
                   * must implicitly open the file here
                   */
                  err = fuse_filehandle_open(vp, FWRITE, &fufh, curthread, cred);
                  closefufh = true;
          }
          if (err) {
                  SDT_PROBE3(fusefs, , vnops, filehandles_closed, vp, uio, cred);
                  return err;
          }
  
          /*
           * Ideally, when the daemon asks for direct io at open time, the
           * standard file flag should be set according to this, so that would
           * just change the default mode, which later on could be changed via
           * fcntl(2).
           * But this doesn't work, the O_DIRECT flag gets cleared at some point
           * (don't know where). So to make any use of the Fuse direct_io option,
           * we hardwire it into the file's private data (similarly to Linux,
           * btw.).
           */
          directio = (ioflag & IO_DIRECT) || !fsess_opt_datacache(vnode_mount(vp));
  
          fuse_vnode_update(vp, FN_MTIMECHANGE | FN_CTIMECHANGE);
          if (directio) {
                  off_t start, end, filesize;
                  bool pages = (ioflag & IO_VMIO) != 0;
  
                  SDT_PROBE2(fusefs, , vnops, trace, 1, "direct write of vnode");
  
                  err = fuse_vnode_size(vp, &filesize, cred, curthread);
                  if (err)
                          goto out;
  
                  start = uio->uio_offset;
                  end = start + uio->uio_resid;
                  if (!pages) {
                          err = fuse_inval_buf_range(vp, filesize, start,
                              end);
                          if (err)
                                  goto out;
                  }
                  err = fuse_write_directbackend(vp, uio, cred, fufh,
                          filesize, ioflag, pages);
          } else {
                  SDT_PROBE2(fusefs, , vnops, trace, 1,
                          "buffered write of vnode");
                  if (!fsess_opt_writeback(vnode_mount(vp)))
                          ioflag |= IO_SYNC;
                  err = fuse_write_biobackend(vp, uio, cred, fufh, ioflag, pid);
          }
          fuse_internal_clear_suid_on_write(vp, cred, uio->uio_td);
  
  out:
          if (closefufh)
                  fuse_filehandle_close(vp, fufh, curthread, cred);
  
          return (err);
  }
  
  static daddr_t
  fuse_gbp_getblkno(struct vnode *vp, vm_ooffset_t off)
  {
          const int biosize = fuse_iosize(vp);
  
          return (off / biosize);
  }
  
  static int
  fuse_gbp_getblksz(struct vnode *vp, daddr_t lbn, long *blksz)
  {
          off_t filesize;
          int err;
          const int biosize = fuse_iosize(vp);
  
          err = fuse_vnode_size(vp, &filesize, NULL, NULL);
          if (err) {
                  /* This will turn into a SIGBUS */
                  return (EIO);
          } else if ((off_t)lbn * biosize >= filesize) {
                  *blksz = 0;
          } else if ((off_t)(lbn + 1) * biosize > filesize) {
                  *blksz = filesize - (off_t)lbn *biosize;
          } else {
                  *blksz = biosize;
          }
          return (0);
  }
  
  /*
      struct vnop_getpages_args {
          struct vnode *a_vp;
          vm_page_t *a_m;
          int a_count;
          int a_reqpage;
      };
  */
  static int
  fuse_vnop_getpages(struct vop_getpages_args *ap)
  {
          struct vnode *vp = ap->a_vp;
  
          if (!fsess_opt_mmap(vnode_mount(vp))) {
                  SDT_PROBE2(fusefs, , vnops, trace, 1,
                          "called on non-cacheable vnode??\n");
                  return (VM_PAGER_ERROR);
          }
  
          return (vfs_bio_getpages(vp, ap->a_m, ap->a_count, ap->a_rbehind,
              ap->a_rahead, fuse_gbp_getblkno, fuse_gbp_getblksz));
  }
  
  static const char extattr_namespace_separator = '.';
  
  /*
      struct vop_getextattr_args {
          struct vop_generic_args a_gen;
          struct vnode *a_vp;
          int a_attrnamespace;
          const char *a_name;
          struct uio *a_uio;
          size_t *a_size;
          struct ucred *a_cred;
          struct thread *a_td;
      };
  */
  static int
  fuse_vnop_getextattr(struct vop_getextattr_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct uio *uio = ap->a_uio;
          struct fuse_dispatcher fdi;
          struct fuse_getxattr_in *get_xattr_in;
          struct fuse_getxattr_out *get_xattr_out;
          struct mount *mp = vnode_mount(vp);
          struct thread *td = ap->a_td;
          struct ucred *cred = ap->a_cred;
          char *prefix;
          char *attr_str;
          size_t len;
          int err;
  
          if (fuse_isdeadfs(vp))
                  return (ENXIO);
  
          if (fsess_not_impl(mp, FUSE_GETXATTR))
                  return EOPNOTSUPP;
  
          err = fuse_extattr_check_cred(vp, ap->a_attrnamespace, cred, td, VREAD);
          if (err)
                  return err;
  
          /* Default to looking for user attributes. */
          if (ap->a_attrnamespace == EXTATTR_NAMESPACE_SYSTEM)
                  prefix = EXTATTR_NAMESPACE_SYSTEM_STRING;
          else
                  prefix = EXTATTR_NAMESPACE_USER_STRING;
  
          len = strlen(prefix) + sizeof(extattr_namespace_separator) +
              strlen(ap->a_name) + 1;
  
          fdisp_init(&fdi, len + sizeof(*get_xattr_in));
          fdisp_make_vp(&fdi, FUSE_GETXATTR, vp, td, cred);
  
          get_xattr_in = fdi.indata;
          /*
           * Check to see whether we're querying the available size or
           * issuing the actual request.  If we pass in 0, we get back struct
           * fuse_getxattr_out.  If we pass in a non-zero size, we get back
           * that much data, without the struct fuse_getxattr_out header.
           */
          if (uio == NULL)
                  get_xattr_in->size = 0;
          else
                  get_xattr_in->size = uio->uio_resid;
  
          attr_str = (char *)fdi.indata + sizeof(*get_xattr_in);
          snprintf(attr_str, len, "%s%c%s", prefix, extattr_namespace_separator,
              ap->a_name);
  
          err = fdisp_wait_answ(&fdi);
          if (err != 0) {
                  if (err == ENOSYS) {
                          fsess_set_notimpl(mp, FUSE_GETXATTR);
                          err = EOPNOTSUPP;
                  }
                  goto out;
          }
  
          get_xattr_out = fdi.answ;
  
          if (ap->a_size != NULL)
                  *ap->a_size = get_xattr_out->size;
  
          if (uio != NULL)
                  err = uiomove(fdi.answ, fdi.iosize, uio);
  
  out:
          fdisp_destroy(&fdi);
          return (err);
  }
  
  /*
      struct vop_setextattr_args {
          struct vop_generic_args a_gen;
          struct vnode *a_vp;
          int a_attrnamespace;
          const char *a_name;
          struct uio *a_uio;
          struct ucred *a_cred;
          struct thread *a_td;
      };
  */
  static int
  fuse_vnop_setextattr(struct vop_setextattr_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct uio *uio = ap->a_uio;
          struct fuse_dispatcher fdi;
          struct fuse_setxattr_in *set_xattr_in;
          struct mount *mp = vnode_mount(vp);
          struct thread *td = ap->a_td;
          struct ucred *cred = ap->a_cred;
          char *prefix;
          size_t len;
          char *attr_str;
          int err;
  
          if (fuse_isdeadfs(vp))
                  return (ENXIO);
  
          if (fsess_not_impl(mp, FUSE_SETXATTR))
                  return EOPNOTSUPP;
  
          if (vfs_isrdonly(mp))
                  return EROFS;
  
          /* Deleting xattrs must use VOP_DELETEEXTATTR instead */
          if (ap->a_uio == NULL) {
                  /*
                   * If we got here as fallback from VOP_DELETEEXTATTR, then
                   * return EOPNOTSUPP.
                   */
                  if (fsess_not_impl(mp, FUSE_REMOVEXATTR))
                          return (EOPNOTSUPP);
                  else
                          return (EINVAL);
          }
  
          err = fuse_extattr_check_cred(vp, ap->a_attrnamespace, cred, td,
                  VWRITE);
          if (err)
                  return err;
  
          /* Default to looking for user attributes. */
          if (ap->a_attrnamespace == EXTATTR_NAMESPACE_SYSTEM)
                  prefix = EXTATTR_NAMESPACE_SYSTEM_STRING;
          else
                  prefix = EXTATTR_NAMESPACE_USER_STRING;
  
          len = strlen(prefix) + sizeof(extattr_namespace_separator) +
              strlen(ap->a_name) + 1;
  
          fdisp_init(&fdi, len + sizeof(*set_xattr_in) + uio->uio_resid);
          fdisp_make_vp(&fdi, FUSE_SETXATTR, vp, td, cred);
  
          set_xattr_in = fdi.indata;
          set_xattr_in->size = uio->uio_resid;
  
          attr_str = (char *)fdi.indata + sizeof(*set_xattr_in);
          snprintf(attr_str, len, "%s%c%s", prefix, extattr_namespace_separator,
              ap->a_name);
  
          err = uiomove((char *)fdi.indata + sizeof(*set_xattr_in) + len,
              uio->uio_resid, uio);
          if (err != 0) {
                  goto out;
          }
  
          err = fdisp_wait_answ(&fdi);
  
          if (err == ENOSYS) {
                  fsess_set_notimpl(mp, FUSE_SETXATTR);
                  err = EOPNOTSUPP;
          }
          if (err == ERESTART) {
                  /* Can't restart after calling uiomove */
                  err = EINTR;
          }
  
  out:
          fdisp_destroy(&fdi);
          return (err);
  }
  
  /*
   * The Linux / FUSE extended attribute list is simply a collection of
   * NUL-terminated strings.  The FreeBSD extended attribute list is a single
   * byte length followed by a non-NUL terminated string.  So, this allows
   * conversion of the Linux / FUSE format to the FreeBSD format in place.
   * Linux attribute names are reported with the namespace as a prefix (e.g.
   * "user.attribute_name"), but in FreeBSD they are reported without the
   * namespace prefix (e.g. "attribute_name").  So, we're going from:
   *
   * user.attr_name1\0user.attr_name2\0
   *
   * to:
   *
   * <num>attr_name1<num>attr_name2
   *
   * Where "<num>" is a single byte number of characters in the attribute name.
   * 
   * Args:
   * prefix - exattr namespace prefix string
   * list, list_len - input list with namespace prefixes
   * bsd_list, bsd_list_len - output list compatible with bsd vfs
   */
  static int
  fuse_xattrlist_convert(char *prefix, const char *list, int list_len,
      char *bsd_list, int *bsd_list_len)
  {
          int len, pos, dist_to_next, prefix_len;
  
          pos = 0;
          *bsd_list_len = 0;
          prefix_len = strlen(prefix);
  
          while (pos < list_len && list[pos] != '\0') {
                  dist_to_next = strlen(&list[pos]) + 1;
                  if (bcmp(&list[pos], prefix, prefix_len) == 0 &&
                      list[pos + prefix_len] == extattr_namespace_separator) {
                          len = dist_to_next -
                              (prefix_len + sizeof(extattr_namespace_separator)) - 1;
                          if (len >= EXTATTR_MAXNAMELEN)
                                  return (ENAMETOOLONG);
  
                          bsd_list[*bsd_list_len] = len;
                          memcpy(&bsd_list[*bsd_list_len + 1],
                              &list[pos + prefix_len +
                              sizeof(extattr_namespace_separator)], len);
  
                          *bsd_list_len += len + 1;
                  }
  
                  pos += dist_to_next;
          }
  
          return (0);
  }
  
  /*
   * List extended attributes
   *
   * The FUSE_LISTXATTR operation is based on Linux's listxattr(2) syscall, which
   * has a number of differences compared to its FreeBSD equivalent,
   * extattr_list_file:
   *
   * - FUSE_LISTXATTR returns all extended attributes across all namespaces,
   *   whereas listxattr(2) only returns attributes for a single namespace
   * - FUSE_LISTXATTR prepends each attribute name with "namespace."
   * - If the provided buffer is not large enough to hold the result,
   *   FUSE_LISTXATTR should return ERANGE, whereas listxattr is expected to
   *   return as many results as will fit.
   */
  /*
      struct vop_listextattr_args {
          struct vop_generic_args a_gen;
          struct vnode *a_vp;
          int a_attrnamespace;
          struct uio *a_uio;
          size_t *a_size;
          struct ucred *a_cred;
          struct thread *a_td;
      };
  */
  static int
  fuse_vnop_listextattr(struct vop_listextattr_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct uio *uio = ap->a_uio;
          struct fuse_dispatcher fdi;
          struct fuse_listxattr_in *list_xattr_in;
          struct fuse_listxattr_out *list_xattr_out;
          struct mount *mp = vnode_mount(vp);
          struct thread *td = ap->a_td;
          struct ucred *cred = ap->a_cred;
          char *prefix;
          char *bsd_list = NULL;
          char *linux_list;
          int bsd_list_len;
          int linux_list_len;
          int err;
  
          if (fuse_isdeadfs(vp))
                  return (ENXIO);
  
          if (fsess_not_impl(mp, FUSE_LISTXATTR))
                  return EOPNOTSUPP;
  
          err = fuse_extattr_check_cred(vp, ap->a_attrnamespace, cred, td, VREAD);
          if (err)
                  return err;
  
          /*
           * Add space for a NUL and the period separator if enabled.
           * Default to looking for user attributes.
           */
          if (ap->a_attrnamespace == EXTATTR_NAMESPACE_SYSTEM)
                  prefix = EXTATTR_NAMESPACE_SYSTEM_STRING;
          else
                  prefix = EXTATTR_NAMESPACE_USER_STRING;
  
          fdisp_init(&fdi, sizeof(*list_xattr_in));
          fdisp_make_vp(&fdi, FUSE_LISTXATTR, vp, td, cred);
  
          /*
           * Retrieve Linux / FUSE compatible list size.
           */
          list_xattr_in = fdi.indata;
          list_xattr_in->size = 0;
  
          err = fdisp_wait_answ(&fdi);
          if (err != 0) {
                  if (err == ENOSYS) {
                          fsess_set_notimpl(mp, FUSE_LISTXATTR);
                          err = EOPNOTSUPP;
                  }
                  goto out;
          }
  
          list_xattr_out = fdi.answ;
          linux_list_len = list_xattr_out->size;
          if (linux_list_len == 0) {
                  if (ap->a_size != NULL)
                          *ap->a_size = linux_list_len;
                  goto out;
          }
  
          /*
           * Retrieve Linux / FUSE compatible list values.
           */
          fdisp_refresh_vp(&fdi, FUSE_LISTXATTR, vp, td, cred);
          list_xattr_in = fdi.indata;
          list_xattr_in->size = linux_list_len;
  
          err = fdisp_wait_answ(&fdi);
          if (err == ERANGE) {
                  /* 
                   * Race detected.  The attribute list must've grown since the
                   * first FUSE_LISTXATTR call.  Start over.  Go all the way back
                   * to userland so we can process signals, if necessary, before
                   * restarting.
                   */
                  err = ERESTART;
                  goto out;
          } else if (err != 0)
                  goto out;
  
          linux_list = fdi.answ;
          /* FUSE doesn't allow the server to return more data than requested */
          if (fdi.iosize > linux_list_len) {
                  struct fuse_data *data = fuse_get_mpdata(mp);
  
                  fuse_warn(data, FSESS_WARN_LSEXTATTR_LONG,
                          "server returned "
                          "more extended attribute data than requested; "
                          "should've returned ERANGE instead.");
          } else {
                  /* But returning less data is fine */
                  linux_list_len = fdi.iosize;
          }
  
          /*
           * Retrieve the BSD compatible list values.
           * The Linux / FUSE attribute list format isn't the same
           * as FreeBSD's format. So we need to transform it into
           * FreeBSD's format before giving it to the user.
           */
          bsd_list = malloc(linux_list_len, M_TEMP, M_WAITOK);
          err = fuse_xattrlist_convert(prefix, linux_list, linux_list_len,
              bsd_list, &bsd_list_len);
          if (err != 0)
                  goto out;
  
          if (ap->a_size != NULL)
                  *ap->a_size = bsd_list_len;
  
          if (uio != NULL)
                  err = uiomove(bsd_list, bsd_list_len, uio);
  
  out:
          free(bsd_list, M_TEMP);
          fdisp_destroy(&fdi);
          return (err);
  }
  
  /*
      struct vop_deallocate_args {
          struct vop_generic_args a_gen;
          struct vnode *a_vp;
          off_t *a_offset;
          off_t *a_len;
          int a_flags;
          int a_ioflag;
          struct ucred *a_cred;
      };
  */
  static int
  fuse_vnop_deallocate(struct vop_deallocate_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct mount *mp = vnode_mount(vp);
          struct fuse_filehandle *fufh;
          struct fuse_dispatcher fdi;
          struct fuse_fallocate_in *ffi;
          struct ucred *cred = ap->a_cred;
          pid_t pid = curthread->td_proc->p_pid;
          off_t *len = ap->a_len;
          off_t *offset = ap->a_offset;
          int ioflag = ap->a_ioflag;
          off_t filesize;
          int err;
          bool closefufh = false;
  
          if (fuse_isdeadfs(vp))
                  return (ENXIO);
  
          if (vfs_isrdonly(mp))
                  return (EROFS);
  
          if (fsess_not_impl(mp, FUSE_FALLOCATE))
                  goto fallback;
  
          err = fuse_filehandle_getrw(vp, FWRITE, &fufh, cred, pid);
          if (err == EBADF && vnode_mount(vp)->mnt_flag & MNT_EXPORTED) {
                  /*
                   * nfsd will do I/O without first doing VOP_OPEN.  We
                   * must implicitly open the file here
                   */
                  err = fuse_filehandle_open(vp, FWRITE, &fufh, curthread, cred);
                  closefufh = true;
          }
          if (err)
                  return (err);
  
          fuse_vnode_update(vp, FN_MTIMECHANGE | FN_CTIMECHANGE);
  
          err = fuse_vnode_size(vp, &filesize, cred, curthread);
          if (err)
                  goto out;
          fuse_inval_buf_range(vp, filesize, *offset, *offset + *len);
  
          fdisp_init(&fdi, sizeof(*ffi));
          fdisp_make_vp(&fdi, FUSE_FALLOCATE, vp, curthread, cred);
          ffi = fdi.indata;
          ffi->fh = fufh->fh_id;
          ffi->offset = *offset;
          ffi->length = *len;
          /*
           * FreeBSD's fspacectl is equivalent to Linux's fallocate with
           * mode == FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE
           */
          ffi->mode = FUSE_FALLOC_FL_PUNCH_HOLE | FUSE_FALLOC_FL_KEEP_SIZE;
          err = fdisp_wait_answ(&fdi);
  
          if (err == ENOSYS) {
                  fsess_set_notimpl(mp, FUSE_FALLOCATE);
                  goto fallback;
          } else if (err == EOPNOTSUPP) {
                  /*
                   * The file system server does not support FUSE_FALLOCATE with
                   * the supplied mode for this particular file.
                   */
                  goto fallback;
          } else if (!err) {
                  /*
                   * Clip the returned offset to EoF.  Do it here rather than
                   * before FUSE_FALLOCATE just in case the kernel's cached file
                   * size is out of date.  Unfortunately, FUSE does not return
                   * any information about filesize from that operation.
                   */
                  *offset = MIN(*offset + *len, filesize);
                  *len = 0;
                  fuse_vnode_undirty_cached_timestamps(vp, false);
                  fuse_internal_clear_suid_on_write(vp, cred, curthread);
  
                  if (ioflag & IO_SYNC)
                          err = fuse_internal_fsync(vp, curthread, MNT_WAIT,
                              false);
          }
  
  out:
          if (closefufh)
                  fuse_filehandle_close(vp, fufh, curthread, cred);
  
          return (err);
  
  fallback:
          if (closefufh)
                  fuse_filehandle_close(vp, fufh, curthread, cred);
  
          return (vop_stddeallocate(ap));
  }
  
  /*
      struct vop_deleteextattr_args {
          struct vop_generic_args a_gen;
          struct vnode *a_vp;
          int a_attrnamespace;
          const char *a_name;
          struct ucred *a_cred;
          struct thread *a_td;
      };
  */
  static int
  fuse_vnop_deleteextattr(struct vop_deleteextattr_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct fuse_dispatcher fdi;
          struct mount *mp = vnode_mount(vp);
          struct thread *td = ap->a_td;
          struct ucred *cred = ap->a_cred;
          char *prefix;
          size_t len;
          char *attr_str;
          int err;
  
          if (fuse_isdeadfs(vp))
                  return (ENXIO);
  
          if (fsess_not_impl(mp, FUSE_REMOVEXATTR))
                  return EOPNOTSUPP;
  
          if (vfs_isrdonly(mp))
                  return EROFS;
  
          err = fuse_extattr_check_cred(vp, ap->a_attrnamespace, cred, td,
                  VWRITE);
          if (err)
                  return err;
  
          /* Default to looking for user attributes. */
          if (ap->a_attrnamespace == EXTATTR_NAMESPACE_SYSTEM)
                  prefix = EXTATTR_NAMESPACE_SYSTEM_STRING;
          else
                  prefix = EXTATTR_NAMESPACE_USER_STRING;
  
          len = strlen(prefix) + sizeof(extattr_namespace_separator) +
              strlen(ap->a_name) + 1;
  
          fdisp_init(&fdi, len);
          fdisp_make_vp(&fdi, FUSE_REMOVEXATTR, vp, td, cred);
  
          attr_str = fdi.indata;
          snprintf(attr_str, len, "%s%c%s", prefix, extattr_namespace_separator,
              ap->a_name);
  
          err = fdisp_wait_answ(&fdi);
          if (err == ENOSYS) {
                  fsess_set_notimpl(mp, FUSE_REMOVEXATTR);
                  err = EOPNOTSUPP;
          }
  
          fdisp_destroy(&fdi);
          return (err);
  }
  
  /*
      struct vnop_print_args {
          struct vnode *a_vp;
      };
  */
  static int
  fuse_vnop_print(struct vop_print_args *ap)
  {
          struct fuse_vnode_data *fvdat = VTOFUD(ap->a_vp);
  
          printf("nodeid: %ju, parent nodeid: %ju, nlookup: %ju, flag: %#x\n",
              (uintmax_t)VTOILLU(ap->a_vp), (uintmax_t)fvdat->parent_nid,
              (uintmax_t)fvdat->nlookup,
              fvdat->flag);
  
          return 0;
  }
  
  /*
   * Get an NFS filehandle for a FUSE file.
   *
   * This will only work for FUSE file systems that guarantee the uniqueness of
   * nodeid:generation, which most don't.
   */
  /*
  vop_vptofh {
          IN struct vnode *a_vp;
          IN struct fid *a_fhp;
  };
  */
  static int
  fuse_vnop_vptofh(struct vop_vptofh_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          struct fuse_vnode_data *fvdat = VTOFUD(vp);
          struct fuse_fid *fhp = (struct fuse_fid *)(ap->a_fhp);
          _Static_assert(sizeof(struct fuse_fid) <= sizeof(struct fid),
                  "FUSE fid type is too big");
          struct mount *mp = vnode_mount(vp);
          struct fuse_data *data = fuse_get_mpdata(mp);
          struct vattr va;
          int err;
  
          if (!(data->dataflags & FSESS_EXPORT_SUPPORT)) {
                  /* NFS requires lookups for "." and ".." */
                  SDT_PROBE2(fusefs, , vnops, trace, 1,
                          "VOP_VPTOFH without FUSE_EXPORT_SUPPORT");
                  return EOPNOTSUPP;
          }
          if ((mp->mnt_flag & MNT_EXPORTED) &&
                  !(data->dataflags & FSESS_NO_OPENDIR_SUPPORT))
          {
                  /*
                   * NFS is stateless, so nfsd must reopen a directory on every
                   * call to VOP_READDIR, passing in the d_off field from the
                   * final dirent of the previous invocation.  But without
                   * FUSE_NO_OPENDIR_SUPPORT, the FUSE protocol does not
                   * guarantee that d_off will be valid after a directory is
                   * closed and reopened.  So prohibit exporting FUSE file
                   * systems that don't set that flag.
                   *
                   * But userspace NFS servers don't have this problem.
                   */
                  SDT_PROBE2(fusefs, , vnops, trace, 1,
                          "VOP_VPTOFH without FUSE_NO_OPENDIR_SUPPORT");
                  return EOPNOTSUPP;
          }
  
          err = fuse_internal_getattr(vp, &va, curthread->td_ucred, curthread);
          if (err)
                  return err;
  
          /*ip = VTOI(ap->a_vp);*/
          /*ufhp = (struct ufid *)ap->a_fhp;*/
          fhp->len = sizeof(struct fuse_fid);
          fhp->nid = fvdat->nid;
          if (fvdat->generation <= UINT32_MAX)
                  fhp->gen = fvdat->generation;
          else
                  return EOVERFLOW;
          return (0);
  }

Cache object: ae4579af3493381976354dc901c2cb5b