FreeBSD/Linux Kernel Cross Reference
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c

     /*
      * CDDL HEADER START
      *
      * The contents of this file are subject to the terms of the
      * Common Development and Distribution License (the "License").
      * You may not use this file except in compliance with the License.
      *
      * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      * or http://www.opensolaris.org/os/licensing.
     * See the License for the specific language governing permissions
     * and limitations under the License.
     *
     * When distributing Covered Code, include this CDDL HEADER in each
     * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     * If applicable, add the following below this CDDL HEADER, with the
     * fields enclosed by brackets "[]" replaced with your own identifying
     * information: Portions Copyright [yyyy] [name of copyright owner]
     *
     * CDDL HEADER END
     */
    
    /*
     * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
     * Copyright (c) 2012, 2015 by Delphix. All rights reserved.
     * Copyright (c) 2014 Integros [integros.com]
     * Copyright 2017 Nexenta Systems, Inc.
     */
    
    /* Portions Copyright 2007 Jeremy Teo */
    /* Portions Copyright 2010 Robert Milkowski */
    
    #include <sys/types.h>
    #include <sys/param.h>
    #include <sys/time.h>
    #include <sys/systm.h>
    #include <sys/sysmacros.h>
    #include <sys/resource.h>
    #include <sys/vfs.h>
    #include <sys/vm.h>
    #include <sys/vnode.h>
    #include <sys/file.h>
    #include <sys/stat.h>
    #include <sys/kmem.h>
    #include <sys/taskq.h>
    #include <sys/uio.h>
    #include <sys/atomic.h>
    #include <sys/namei.h>
    #include <sys/mman.h>
    #include <sys/cmn_err.h>
    #include <sys/errno.h>
    #include <sys/unistd.h>
    #include <sys/zfs_dir.h>
    #include <sys/zfs_ioctl.h>
    #include <sys/fs/zfs.h>
    #include <sys/dmu.h>
    #include <sys/dmu_objset.h>
    #include <sys/spa.h>
    #include <sys/txg.h>
    #include <sys/dbuf.h>
    #include <sys/zap.h>
    #include <sys/sa.h>
    #include <sys/dirent.h>
    #include <sys/policy.h>
    #include <sys/sunddi.h>
    #include <sys/filio.h>
    #include <sys/sid.h>
    #include <sys/zfs_ctldir.h>
    #include <sys/zfs_fuid.h>
    #include <sys/zfs_sa.h>
    #include <sys/zfs_rlock.h>
    #include <sys/extdirent.h>
    #include <sys/kidmap.h>
    #include <sys/bio.h>
    #include <sys/buf.h>
    #include <sys/sched.h>
    #include <sys/acl.h>
    #include <sys/vmmeter.h>
    #include <vm/vm_param.h>
    #include <sys/zil.h>
    
    /*
     * Programming rules.
     *
     * Each vnode op performs some logical unit of work.  To do this, the ZPL must
     * properly lock its in-core state, create a DMU transaction, do the work,
     * record this work in the intent log (ZIL), commit the DMU transaction,
     * and wait for the intent log to commit if it is a synchronous operation.
     * Moreover, the vnode ops must work in both normal and log replay context.
     * The ordering of events is important to avoid deadlocks and references
     * to freed memory.  The example below illustrates the following Big Rules:
     *
     *  (1) A check must be made in each zfs thread for a mounted file system.
     *      This is done avoiding races using ZFS_ENTER(zfsvfs).
     *      A ZFS_EXIT(zfsvfs) is needed before all returns.  Any znodes
     *      must be checked with ZFS_VERIFY_ZP(zp).  Both of these macros
     *      can return EIO from the calling function.
     *
     *  (2) VN_RELE() should always be the last thing except for zil_commit()
     *      (if necessary) and ZFS_EXIT(). This is for 3 reasons:
    *      First, if it's the last reference, the vnode/znode
    *      can be freed, so the zp may point to freed memory.  Second, the last
    *      reference will call zfs_zinactive(), which may induce a lot of work --
    *      pushing cached pages (which acquires range locks) and syncing out
    *      cached atime changes.  Third, zfs_zinactive() may require a new tx,
    *      which could deadlock the system if you were already holding one.
    *      If you must call VN_RELE() within a tx then use VN_RELE_ASYNC().
    *
    *  (3) All range locks must be grabbed before calling dmu_tx_assign(),
    *      as they can span dmu_tx_assign() calls.
    *
    *  (4) If ZPL locks are held, pass TXG_NOWAIT as the second argument to
    *      dmu_tx_assign().  This is critical because we don't want to block
    *      while holding locks.
    *
    *      If no ZPL locks are held (aside from ZFS_ENTER()), use TXG_WAIT.  This
    *      reduces lock contention and CPU usage when we must wait (note that if
    *      throughput is constrained by the storage, nearly every transaction
    *      must wait).
    *
    *      Note, in particular, that if a lock is sometimes acquired before
    *      the tx assigns, and sometimes after (e.g. z_lock), then failing
    *      to use a non-blocking assign can deadlock the system.  The scenario:
    *
    *      Thread A has grabbed a lock before calling dmu_tx_assign().
    *      Thread B is in an already-assigned tx, and blocks for this lock.
    *      Thread A calls dmu_tx_assign(TXG_WAIT) and blocks in txg_wait_open()
    *      forever, because the previous txg can't quiesce until B's tx commits.
    *
    *      If dmu_tx_assign() returns ERESTART and zfsvfs->z_assign is TXG_NOWAIT,
    *      then drop all locks, call dmu_tx_wait(), and try again.  On subsequent
    *      calls to dmu_tx_assign(), pass TXG_NOTHROTTLE in addition to TXG_NOWAIT,
    *      to indicate that this operation has already called dmu_tx_wait().
    *      This will ensure that we don't retry forever, waiting a short bit
    *      each time.
    *
    *  (5) If the operation succeeded, generate the intent log entry for it
    *      before dropping locks.  This ensures that the ordering of events
    *      in the intent log matches the order in which they actually occurred.
    *      During ZIL replay the zfs_log_* functions will update the sequence
    *      number to indicate the zil transaction has replayed.
    *
    *  (6) At the end of each vnode op, the DMU tx must always commit,
    *      regardless of whether there were any errors.
    *
    *  (7) After dropping all locks, invoke zil_commit(zilog, foid)
    *      to ensure that synchronous semantics are provided when necessary.
    *
    * In general, this is how things should be ordered in each vnode op:
    *
    *      ZFS_ENTER(zfsvfs);              // exit if unmounted
    * top:
    *      zfs_dirent_lookup(&dl, ...)     // lock directory entry (may VN_HOLD())
    *      rw_enter(...);                  // grab any other locks you need
    *      tx = dmu_tx_create(...);        // get DMU tx
    *      dmu_tx_hold_*();                // hold each object you might modify
    *      error = dmu_tx_assign(tx, (waited ? TXG_NOTHROTTLE : 0) | TXG_NOWAIT);
    *      if (error) {
    *              rw_exit(...);           // drop locks
    *              zfs_dirent_unlock(dl);  // unlock directory entry
    *              VN_RELE(...);           // release held vnodes
    *              if (error == ERESTART) {
    *                      waited = B_TRUE;
    *                      dmu_tx_wait(tx);
    *                      dmu_tx_abort(tx);
    *                      goto top;
    *              }
    *              dmu_tx_abort(tx);       // abort DMU tx
    *              ZFS_EXIT(zfsvfs);       // finished in zfs
    *              return (error);         // really out of space
    *      }
    *      error = do_real_work();         // do whatever this VOP does
    *      if (error == 0)
    *              zfs_log_*(...);         // on success, make ZIL entry
    *      dmu_tx_commit(tx);              // commit DMU tx -- error or not
    *      rw_exit(...);                   // drop locks
    *      zfs_dirent_unlock(dl);          // unlock directory entry
    *      VN_RELE(...);                   // release held vnodes
    *      zil_commit(zilog, foid);        // synchronous when necessary
    *      ZFS_EXIT(zfsvfs);               // finished in zfs
    *      return (error);                 // done, report error
    */
   
   /* ARGSUSED */
   static int
   zfs_open(vnode_t **vpp, int flag, cred_t *cr, caller_context_t *ct)
   {
           znode_t *zp = VTOZ(*vpp);
           zfsvfs_t *zfsvfs = zp->z_zfsvfs;
   
           ZFS_ENTER(zfsvfs);
           ZFS_VERIFY_ZP(zp);
   
           if ((flag & FWRITE) && (zp->z_pflags & ZFS_APPENDONLY) &&
               ((flag & FAPPEND) == 0)) {
                   ZFS_EXIT(zfsvfs);
                   return (SET_ERROR(EPERM));
           }
   
           if (!zfs_has_ctldir(zp) && zp->z_zfsvfs->z_vscan &&
               ZTOV(zp)->v_type == VREG &&
               !(zp->z_pflags & ZFS_AV_QUARANTINED) && zp->z_size > 0) {
                   if (fs_vscan(*vpp, cr, 0) != 0) {
                           ZFS_EXIT(zfsvfs);
                           return (SET_ERROR(EACCES));
                   }
           }
   
           /* Keep a count of the synchronous opens in the znode */
           if (flag & (FSYNC | FDSYNC))
                   atomic_inc_32(&zp->z_sync_cnt);
   
           ZFS_EXIT(zfsvfs);
           return (0);
   }
   
   /* ARGSUSED */
   static int
   zfs_close(vnode_t *vp, int flag, int count, offset_t offset, cred_t *cr,
       caller_context_t *ct)
   {
           znode_t *zp = VTOZ(vp);
           zfsvfs_t *zfsvfs = zp->z_zfsvfs;
   
           /*
            * Clean up any locks held by this process on the vp.
            */
           cleanlocks(vp, ddi_get_pid(), 0);
           cleanshares(vp, ddi_get_pid());
   
           ZFS_ENTER(zfsvfs);
           ZFS_VERIFY_ZP(zp);
   
           /* Decrement the synchronous opens in the znode */
           if ((flag & (FSYNC | FDSYNC)) && (count == 1))
                   atomic_dec_32(&zp->z_sync_cnt);
   
           if (!zfs_has_ctldir(zp) && zp->z_zfsvfs->z_vscan &&
               ZTOV(zp)->v_type == VREG &&
               !(zp->z_pflags & ZFS_AV_QUARANTINED) && zp->z_size > 0)
                   VERIFY(fs_vscan(vp, cr, 1) == 0);
   
           ZFS_EXIT(zfsvfs);
           return (0);
   }
   
   /*
    * Lseek support for finding holes (cmd == _FIO_SEEK_HOLE) and
    * data (cmd == _FIO_SEEK_DATA). "off" is an in/out parameter.
    */
   static int
   zfs_holey(vnode_t *vp, u_long cmd, offset_t *off)
   {
           znode_t *zp = VTOZ(vp);
           uint64_t noff = (uint64_t)*off; /* new offset */
           uint64_t file_sz;
           int error;
           boolean_t hole;
   
           file_sz = zp->z_size;
           if (noff >= file_sz)  {
                   return (SET_ERROR(ENXIO));
           }
   
           if (cmd == _FIO_SEEK_HOLE)
                   hole = B_TRUE;
           else
                   hole = B_FALSE;
   
           error = dmu_offset_next(zp->z_zfsvfs->z_os, zp->z_id, hole, &noff);
   
           if (error == ESRCH)
                   return (SET_ERROR(ENXIO));
   
           /*
            * We could find a hole that begins after the logical end-of-file,
            * because dmu_offset_next() only works on whole blocks.  If the
            * EOF falls mid-block, then indicate that the "virtual hole"
            * at the end of the file begins at the logical EOF, rather than
            * at the end of the last block.
            */
           if (noff > file_sz) {
                   ASSERT(hole);
                   noff = file_sz;
           }
   
           if (noff < *off)
                   return (error);
           *off = noff;
           return (error);
   }
   
   /* ARGSUSED */
   static int
   zfs_ioctl(vnode_t *vp, u_long com, intptr_t data, int flag, cred_t *cred,
       int *rvalp, caller_context_t *ct)
   {
           offset_t off;
           offset_t ndata;
           dmu_object_info_t doi;
           int error;
           zfsvfs_t *zfsvfs;
           znode_t *zp;
   
           switch (com) {
           case _FIOFFS:
           {
                   return (0);
   
                   /*
                    * The following two ioctls are used by bfu.  Faking out,
                    * necessary to avoid bfu errors.
                    */
           }
           case _FIOGDIO:
           case _FIOSDIO:
           {
                   return (0);
           }
   
           case _FIO_SEEK_DATA:
           case _FIO_SEEK_HOLE:
           {
   #ifdef illumos
                   if (ddi_copyin((void *)data, &off, sizeof (off), flag))
                           return (SET_ERROR(EFAULT));
   #else
                   off = *(offset_t *)data;
   #endif
                   zp = VTOZ(vp);
                   zfsvfs = zp->z_zfsvfs;
                   ZFS_ENTER(zfsvfs);
                   ZFS_VERIFY_ZP(zp);
   
                   /* offset parameter is in/out */
                   error = zfs_holey(vp, com, &off);
                   ZFS_EXIT(zfsvfs);
                   if (error)
                           return (error);
   #ifdef illumos
                   if (ddi_copyout(&off, (void *)data, sizeof (off), flag))
                           return (SET_ERROR(EFAULT));
   #else
                   *(offset_t *)data = off;
   #endif
                   return (0);
           }
   #ifdef illumos
           case _FIO_COUNT_FILLED:
           {
                   /*
                    * _FIO_COUNT_FILLED adds a new ioctl command which
                    * exposes the number of filled blocks in a
                    * ZFS object.
                    */
                   zp = VTOZ(vp);
                   zfsvfs = zp->z_zfsvfs;
                   ZFS_ENTER(zfsvfs);
                   ZFS_VERIFY_ZP(zp);
   
                   /*
                    * Wait for all dirty blocks for this object
                    * to get synced out to disk, and the DMU info
                    * updated.
                    */
                   error = dmu_object_wait_synced(zfsvfs->z_os, zp->z_id);
                   if (error) {
                           ZFS_EXIT(zfsvfs);
                           return (error);
                   }
   
                   /*
                    * Retrieve fill count from DMU object.
                    */
                   error = dmu_object_info(zfsvfs->z_os, zp->z_id, &doi);
                   if (error) {
                           ZFS_EXIT(zfsvfs);
                           return (error);
                   }
   
                   ndata = doi.doi_fill_count;
   
                   ZFS_EXIT(zfsvfs);
                   if (ddi_copyout(&ndata, (void *)data, sizeof (ndata), flag))
                           return (SET_ERROR(EFAULT));
                   return (0);
           }
   #endif
           }
           return (SET_ERROR(ENOTTY));
   }
   
   static vm_page_t
   page_busy(vnode_t *vp, int64_t start, int64_t off, int64_t nbytes)
   {
           vm_object_t obj;
           vm_page_t pp;
           int64_t end;
   
           /*
            * At present vm_page_clear_dirty extends the cleared range to DEV_BSIZE
            * aligned boundaries, if the range is not aligned.  As a result a
            * DEV_BSIZE subrange with partially dirty data may get marked as clean.
            * It may happen that all DEV_BSIZE subranges are marked clean and thus
            * the whole page would be considred clean despite have some dirty data.
            * For this reason we should shrink the range to DEV_BSIZE aligned
            * boundaries before calling vm_page_clear_dirty.
            */
           end = rounddown2(off + nbytes, DEV_BSIZE);
           off = roundup2(off, DEV_BSIZE);
           nbytes = end - off;
   
           obj = vp->v_object;
           zfs_vmobject_assert_wlocked(obj);
   
           for (;;) {
                   if ((pp = vm_page_lookup(obj, OFF_TO_IDX(start))) != NULL &&
                       pp->valid) {
                           if (vm_page_xbusied(pp)) {
                                   /*
                                    * Reference the page before unlocking and
                                    * sleeping so that the page daemon is less
                                    * likely to reclaim it.
                                    */
                                   vm_page_reference(pp);
                                   vm_page_lock(pp);
                                   zfs_vmobject_wunlock(obj);
                                   vm_page_busy_sleep(pp, "zfsmwb", true);
                                   zfs_vmobject_wlock(obj);
                                   continue;
                           }
                           vm_page_sbusy(pp);
                   } else if (pp != NULL) {
                           ASSERT(!pp->valid);
                           pp = NULL;
                   }
   
                   if (pp != NULL) {
                           ASSERT3U(pp->valid, ==, VM_PAGE_BITS_ALL);
                           vm_object_pip_add(obj, 1);
                           pmap_remove_write(pp);
                           if (nbytes != 0)
                                   vm_page_clear_dirty(pp, off, nbytes);
                   }
                   break;
           }
           return (pp);
   }
   
   static void
   page_unbusy(vm_page_t pp)
   {
   
           vm_page_sunbusy(pp);
           vm_object_pip_subtract(pp->object, 1);
   }
   
   static vm_page_t
   page_hold(vnode_t *vp, int64_t start)
   {
           vm_object_t obj;
           vm_page_t pp;
   
           obj = vp->v_object;
           zfs_vmobject_assert_wlocked(obj);
   
           for (;;) {
                   if ((pp = vm_page_lookup(obj, OFF_TO_IDX(start))) != NULL &&
                       pp->valid) {
                           if (vm_page_xbusied(pp)) {
                                   /*
                                    * Reference the page before unlocking and
                                    * sleeping so that the page daemon is less
                                    * likely to reclaim it.
                                    */
                                   vm_page_reference(pp);
                                   vm_page_lock(pp);
                                   zfs_vmobject_wunlock(obj);
                                   vm_page_busy_sleep(pp, "zfsmwb", true);
                                   zfs_vmobject_wlock(obj);
                                   continue;
                           }
   
                           ASSERT3U(pp->valid, ==, VM_PAGE_BITS_ALL);
                           vm_page_lock(pp);
                           vm_page_hold(pp);
                           vm_page_unlock(pp);
   
                   } else
                           pp = NULL;
                   break;
           }
           return (pp);
   }
   
   static void
   page_unhold(vm_page_t pp)
   {
   
           vm_page_lock(pp);
           vm_page_unhold(pp);
           vm_page_unlock(pp);
   }
   
   /*
    * When a file is memory mapped, we must keep the IO data synchronized
    * between the DMU cache and the memory mapped pages.  What this means:
    *
    * On Write:    If we find a memory mapped page, we write to *both*
    *              the page and the dmu buffer.
    */
   static void
   update_pages(vnode_t *vp, int64_t start, int len, objset_t *os, uint64_t oid,
       int segflg, dmu_tx_t *tx)
   {
           vm_object_t obj;
           struct sf_buf *sf;
           caddr_t va;
           int off;
   
           ASSERT(segflg != UIO_NOCOPY);
           ASSERT(vp->v_mount != NULL);
           obj = vp->v_object;
           ASSERT(obj != NULL);
   
           off = start & PAGEOFFSET;
           zfs_vmobject_wlock(obj);
           for (start &= PAGEMASK; len > 0; start += PAGESIZE) {
                   vm_page_t pp;
                   int nbytes = imin(PAGESIZE - off, len);
   
                   if ((pp = page_busy(vp, start, off, nbytes)) != NULL) {
                           zfs_vmobject_wunlock(obj);
   
                           va = zfs_map_page(pp, &sf);
                           (void) dmu_read(os, oid, start+off, nbytes,
                               va+off, DMU_READ_PREFETCH);;
                           zfs_unmap_page(sf);
   
                           zfs_vmobject_wlock(obj);
                           page_unbusy(pp);
                   }
                   len -= nbytes;
                   off = 0;
           }
           vm_object_pip_wakeupn(obj, 0);
           zfs_vmobject_wunlock(obj);
   }
   
   /*
    * Read with UIO_NOCOPY flag means that sendfile(2) requests
    * ZFS to populate a range of page cache pages with data.
    *
    * NOTE: this function could be optimized to pre-allocate
    * all pages in advance, drain exclusive busy on all of them,
    * map them into contiguous KVA region and populate them
    * in one single dmu_read() call.
    */
   static int
   mappedread_sf(vnode_t *vp, int nbytes, uio_t *uio)
   {
           znode_t *zp = VTOZ(vp);
           objset_t *os = zp->z_zfsvfs->z_os;
           struct sf_buf *sf;
           vm_object_t obj;
           vm_page_t pp;
           int64_t start;
           caddr_t va;
           int len = nbytes;
           int off;
           int error = 0;
   
           ASSERT(uio->uio_segflg == UIO_NOCOPY);
           ASSERT(vp->v_mount != NULL);
           obj = vp->v_object;
           ASSERT(obj != NULL);
           ASSERT((uio->uio_loffset & PAGEOFFSET) == 0);
   
           zfs_vmobject_wlock(obj);
           for (start = uio->uio_loffset; len > 0; start += PAGESIZE) {
                   int bytes = MIN(PAGESIZE, len);
   
                   pp = vm_page_grab(obj, OFF_TO_IDX(start), VM_ALLOC_SBUSY |
                       VM_ALLOC_NORMAL | VM_ALLOC_IGN_SBUSY);
                   if (pp->valid == 0) {
                           zfs_vmobject_wunlock(obj);
                           va = zfs_map_page(pp, &sf);
                           error = dmu_read(os, zp->z_id, start, bytes, va,
                               DMU_READ_PREFETCH);
                           if (bytes != PAGESIZE && error == 0)
                                   bzero(va + bytes, PAGESIZE - bytes);
                           zfs_unmap_page(sf);
                           zfs_vmobject_wlock(obj);
                           vm_page_sunbusy(pp);
                           vm_page_lock(pp);
                           if (error) {
                                   if (pp->wire_count == 0 && pp->valid == 0 &&
                                       !vm_page_busied(pp))
                                           vm_page_free(pp);
                           } else {
                                   pp->valid = VM_PAGE_BITS_ALL;
                                   vm_page_activate(pp);
                           }
                           vm_page_unlock(pp);
                   } else {
                           ASSERT3U(pp->valid, ==, VM_PAGE_BITS_ALL);
                           vm_page_sunbusy(pp);
                   }
                   if (error)
                           break;
                   uio->uio_resid -= bytes;
                   uio->uio_offset += bytes;
                   len -= bytes;
           }
           zfs_vmobject_wunlock(obj);
           return (error);
   }
   
   /*
    * When a file is memory mapped, we must keep the IO data synchronized
    * between the DMU cache and the memory mapped pages.  What this means:
    *
    * On Read:     We "read" preferentially from memory mapped pages,
    *              else we default from the dmu buffer.
    *
    * NOTE: We will always "break up" the IO into PAGESIZE uiomoves when
    *       the file is memory mapped.
    */
   static int
   mappedread(vnode_t *vp, int nbytes, uio_t *uio)
   {
           znode_t *zp = VTOZ(vp);
           vm_object_t obj;
           int64_t start;
           caddr_t va;
           int len = nbytes;
           int off;
           int error = 0;
   
           ASSERT(vp->v_mount != NULL);
           obj = vp->v_object;
           ASSERT(obj != NULL);
   
           start = uio->uio_loffset;
           off = start & PAGEOFFSET;
           zfs_vmobject_wlock(obj);
           for (start &= PAGEMASK; len > 0; start += PAGESIZE) {
                   vm_page_t pp;
                   uint64_t bytes = MIN(PAGESIZE - off, len);
   
                   if (pp = page_hold(vp, start)) {
                           struct sf_buf *sf;
                           caddr_t va;
   
                           zfs_vmobject_wunlock(obj);
                           va = zfs_map_page(pp, &sf);
   #ifdef illumos
                           error = uiomove(va + off, bytes, UIO_READ, uio);
   #else
                           error = vn_io_fault_uiomove(va + off, bytes, uio);
   #endif
                           zfs_unmap_page(sf);
                           zfs_vmobject_wlock(obj);
                           page_unhold(pp);
                   } else {
                           zfs_vmobject_wunlock(obj);
                           error = dmu_read_uio_dbuf(sa_get_db(zp->z_sa_hdl),
                               uio, bytes);
                           zfs_vmobject_wlock(obj);
                   }
                   len -= bytes;
                   off = 0;
                   if (error)
                           break;
           }
           zfs_vmobject_wunlock(obj);
           return (error);
   }
   
   offset_t zfs_read_chunk_size = 1024 * 1024; /* Tunable */
   
   /*
    * Read bytes from specified file into supplied buffer.
    *
    *      IN:     vp      - vnode of file to be read from.
    *              uio     - structure supplying read location, range info,
    *                        and return buffer.
    *              ioflag  - SYNC flags; used to provide FRSYNC semantics.
    *              cr      - credentials of caller.
    *              ct      - caller context
    *
    *      OUT:    uio     - updated offset and range, buffer filled.
    *
    *      RETURN: 0 on success, error code on failure.
    *
    * Side Effects:
    *      vp - atime updated if byte count > 0
    */
   /* ARGSUSED */
   static int
   zfs_read(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cr, caller_context_t *ct)
   {
           znode_t         *zp = VTOZ(vp);
           zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
           ssize_t         n, nbytes;
           int             error = 0;
           rl_t            *rl;
           xuio_t          *xuio = NULL;
   
           ZFS_ENTER(zfsvfs);
           ZFS_VERIFY_ZP(zp);
   
           if (zp->z_pflags & ZFS_AV_QUARANTINED) {
                   ZFS_EXIT(zfsvfs);
                   return (SET_ERROR(EACCES));
           }
   
           /*
            * Validate file offset
            */
           if (uio->uio_loffset < (offset_t)0) {
                   ZFS_EXIT(zfsvfs);
                   return (SET_ERROR(EINVAL));
           }
   
           /*
            * Fasttrack empty reads
            */
           if (uio->uio_resid == 0) {
                   ZFS_EXIT(zfsvfs);
                   return (0);
           }
   
           /*
            * Check for mandatory locks
            */
           if (MANDMODE(zp->z_mode)) {
                   if (error = chklock(vp, FREAD,
                       uio->uio_loffset, uio->uio_resid, uio->uio_fmode, ct)) {
                           ZFS_EXIT(zfsvfs);
                           return (error);
                   }
           }
   
           /*
            * If we're in FRSYNC mode, sync out this znode before reading it.
            */
           if (zfsvfs->z_log &&
               (ioflag & FRSYNC || zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS))
                   zil_commit(zfsvfs->z_log, zp->z_id);
   
           /*
            * Lock the range against changes.
            */
           rl = zfs_range_lock(zp, uio->uio_loffset, uio->uio_resid, RL_READER);
   
           /*
            * If we are reading past end-of-file we can skip
            * to the end; but we might still need to set atime.
            */
           if (uio->uio_loffset >= zp->z_size) {
                   error = 0;
                   goto out;
           }
   
           ASSERT(uio->uio_loffset < zp->z_size);
           n = MIN(uio->uio_resid, zp->z_size - uio->uio_loffset);
   
   #ifdef illumos
           if ((uio->uio_extflg == UIO_XUIO) &&
               (((xuio_t *)uio)->xu_type == UIOTYPE_ZEROCOPY)) {
                   int nblk;
                   int blksz = zp->z_blksz;
                   uint64_t offset = uio->uio_loffset;
   
                   xuio = (xuio_t *)uio;
                   if ((ISP2(blksz))) {
                           nblk = (P2ROUNDUP(offset + n, blksz) - P2ALIGN(offset,
                               blksz)) / blksz;
                   } else {
                           ASSERT(offset + n <= blksz);
                           nblk = 1;
                   }
                   (void) dmu_xuio_init(xuio, nblk);
   
                   if (vn_has_cached_data(vp)) {
                           /*
                            * For simplicity, we always allocate a full buffer
                            * even if we only expect to read a portion of a block.
                            */
                           while (--nblk >= 0) {
                                   (void) dmu_xuio_add(xuio,
                                       dmu_request_arcbuf(sa_get_db(zp->z_sa_hdl),
                                       blksz), 0, blksz);
                           }
                   }
           }
   #endif  /* illumos */
   
           while (n > 0) {
                   nbytes = MIN(n, zfs_read_chunk_size -
                       P2PHASE(uio->uio_loffset, zfs_read_chunk_size));
   
   #ifdef __FreeBSD__
                   if (uio->uio_segflg == UIO_NOCOPY)
                           error = mappedread_sf(vp, nbytes, uio);
                   else
   #endif /* __FreeBSD__ */
                   if (vn_has_cached_data(vp)) {
                           error = mappedread(vp, nbytes, uio);
                   } else {
                           error = dmu_read_uio_dbuf(sa_get_db(zp->z_sa_hdl),
                               uio, nbytes);
                   }
                   if (error) {
                           /* convert checksum errors into IO errors */
                           if (error == ECKSUM)
                                   error = SET_ERROR(EIO);
                           break;
                   }
   
                   n -= nbytes;
           }
   out:
           zfs_range_unlock(rl);
   
           ZFS_ACCESSTIME_STAMP(zfsvfs, zp);
           ZFS_EXIT(zfsvfs);
           return (error);
   }
   
   /*
    * Write the bytes to a file.
    *
    *      IN:     vp      - vnode of file to be written to.
    *              uio     - structure supplying write location, range info,
    *                        and data buffer.
    *              ioflag  - FAPPEND, FSYNC, and/or FDSYNC.  FAPPEND is
    *                        set if in append mode.
    *              cr      - credentials of caller.
    *              ct      - caller context (NFS/CIFS fem monitor only)
    *
    *      OUT:    uio     - updated offset and range.
    *
    *      RETURN: 0 on success, error code on failure.
    *
    * Timestamps:
    *      vp - ctime|mtime updated if byte count > 0
    */
   
   /* ARGSUSED */
   static int
   zfs_write(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cr, caller_context_t *ct)
   {
           znode_t         *zp = VTOZ(vp);
           rlim64_t        limit = MAXOFFSET_T;
           ssize_t         start_resid = uio->uio_resid;
           ssize_t         tx_bytes;
           uint64_t        end_size;
           dmu_tx_t        *tx;
           zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
           zilog_t         *zilog;
           offset_t        woff;
           ssize_t         n, nbytes;
           rl_t            *rl;
           int             max_blksz = zfsvfs->z_max_blksz;
           int             error = 0;
           arc_buf_t       *abuf;
           iovec_t         *aiov = NULL;
           xuio_t          *xuio = NULL;
           int             i_iov = 0;
           int             iovcnt = uio->uio_iovcnt;
           iovec_t         *iovp = uio->uio_iov;
           int             write_eof;
           int             count = 0;
           sa_bulk_attr_t  bulk[4];
           uint64_t        mtime[2], ctime[2];
   
           /*
            * Fasttrack empty write
            */
           n = start_resid;
           if (n == 0)
                   return (0);
   
           if (limit == RLIM64_INFINITY || limit > MAXOFFSET_T)
                   limit = MAXOFFSET_T;
   
           ZFS_ENTER(zfsvfs);
           ZFS_VERIFY_ZP(zp);
   
           SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs), NULL, &mtime, 16);
           SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL, &ctime, 16);
           SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_SIZE(zfsvfs), NULL,
               &zp->z_size, 8);
           SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
               &zp->z_pflags, 8);
   
           /*
            * In a case vp->v_vfsp != zp->z_zfsvfs->z_vfs (e.g. snapshots) our
            * callers might not be able to detect properly that we are read-only,
            * so check it explicitly here.
            */
           if (zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) {
                   ZFS_EXIT(zfsvfs);
                   return (SET_ERROR(EROFS));
           }
   
           /*
            * If immutable or not appending then return EPERM.
            * Intentionally allow ZFS_READONLY through here.
            * See zfs_zaccess_common()
            */
           if ((zp->z_pflags & ZFS_IMMUTABLE) ||
               ((zp->z_pflags & ZFS_APPENDONLY) && !(ioflag & FAPPEND) &&
               (uio->uio_loffset < zp->z_size))) {
                   ZFS_EXIT(zfsvfs);
                   return (SET_ERROR(EPERM));
           }
   
           zilog = zfsvfs->z_log;
   
           /*
            * Validate file offset
            */
           woff = ioflag & FAPPEND ? zp->z_size : uio->uio_loffset;
           if (woff < 0) {
                   ZFS_EXIT(zfsvfs);
                   return (SET_ERROR(EINVAL));
           }
   
           /*
            * Check for mandatory locks before calling zfs_range_lock()
            * in order to prevent a deadlock with locks set via fcntl().
            */
           if (MANDMODE((mode_t)zp->z_mode) &&
               (error = chklock(vp, FWRITE, woff, n, uio->uio_fmode, ct)) != 0) {
                   ZFS_EXIT(zfsvfs);
                   return (error);
           }
   
   #ifdef illumos
           /*
            * Pre-fault the pages to ensure slow (eg NFS) pages
            * don't hold up txg.
            * Skip this if uio contains loaned arc_buf.
            */
           if ((uio->uio_extflg == UIO_XUIO) &&
               (((xuio_t *)uio)->xu_type == UIOTYPE_ZEROCOPY))
                   xuio = (xuio_t *)uio;
           else
                   uio_prefaultpages(MIN(n, max_blksz), uio);
   #endif
   
           /*
            * If in append mode, set the io offset pointer to eof.
            */
           if (ioflag & FAPPEND) {
                   /*
                    * Obtain an appending range lock to guarantee file append
                    * semantics.  We reset the write offset once we have the lock.
                    */
                   rl = zfs_range_lock(zp, 0, n, RL_APPEND);
                   woff = rl->r_off;
                   if (rl->r_len == UINT64_MAX) {
                           /*
                            * We overlocked the file because this write will cause
                            * the file block size to increase.
                            * Note that zp_size cannot change with this lock held.
                            */
                           woff = zp->z_size;
                   }
                   uio->uio_loffset = woff;
           } else {
                   /*
                    * Note that if the file block size will change as a result of
                    * this write, then this range lock will lock the entire file
                    * so that we can re-write the block safely.
                    */
                   rl = zfs_range_lock(zp, woff, n, RL_WRITER);
           }
   
           if (vn_rlimit_fsize(vp, uio, uio->uio_td)) {
                   zfs_range_unlock(rl);
                   ZFS_EXIT(zfsvfs);
                   return (EFBIG);
           }
   
           if (woff >= limit) {
                   zfs_range_unlock(rl);
                   ZFS_EXIT(zfsvfs);
                   return (SET_ERROR(EFBIG));
           }
   
           if ((woff + n) > limit || woff > (limit - n))
                   n = limit - woff;
   
           /* Will this write extend the file length? */
           write_eof = (woff + n > zp->z_size);
   
          end_size = MAX(zp->z_size, woff + n);
  
          /*
           * Write the file in reasonable size chunks.  Each chunk is written
           * in a separate transaction; this keeps the intent log records small
           * and allows us to do more fine-grained space accounting.
           */
          while (n > 0) {
                  abuf = NULL;
                  woff = uio->uio_loffset;
                  if (zfs_owner_overquota(zfsvfs, zp, B_FALSE) ||
                      zfs_owner_overquota(zfsvfs, zp, B_TRUE)) {
                          if (abuf != NULL)
                                  dmu_return_arcbuf(abuf);
                          error = SET_ERROR(EDQUOT);
                          break;
                  }
  
                  if (xuio && abuf == NULL) {
                          ASSERT(i_iov < iovcnt);
                          aiov = &iovp[i_iov];
                          abuf = dmu_xuio_arcbuf(xuio, i_iov);
                          dmu_xuio_clear(xuio, i_iov);
                          DTRACE_PROBE3(zfs_cp_write, int, i_iov,
                              iovec_t *, aiov, arc_buf_t *, abuf);
                          ASSERT((aiov->iov_base == abuf->b_data) ||
                              ((char *)aiov->iov_base - (char *)abuf->b_data +
                              aiov->iov_len == arc_buf_size(abuf)));
                          i_iov++;
                  } else if (abuf == NULL && n >= max_blksz &&
                      woff >= zp->z_size &&
                      P2PHASE(woff, max_blksz) == 0 &&
                      zp->z_blksz == max_blksz) {
                          /*
                           * This write covers a full block.  "Borrow" a buffer
                           * from the dmu so that we can fill it before we enter
                           * a transaction.  This avoids the possibility of
                           * holding up the transaction if the data copy hangs
                           * up on a pagefault (e.g., from an NFS server mapping).
                           */
                          size_t cbytes;
  
                          abuf = dmu_request_arcbuf(sa_get_db(zp->z_sa_hdl),
                              max_blksz);
                          ASSERT(abuf != NULL);
                          ASSERT(arc_buf_size(abuf) == max_blksz);
                          if (error = uiocopy(abuf->b_data, max_blksz,
                              UIO_WRITE, uio, &cbytes)) {
                                  dmu_return_arcbuf(abuf);
                                  break;
                          }
                          ASSERT(cbytes == max_blksz);
                  }
  
                  /*
                   * Start a transaction.
                   */
                  tx = dmu_tx_create(zfsvfs->z_os);
                  dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE);
                  dmu_tx_hold_write(tx, zp->z_id, woff, MIN(n, max_blksz));
                  zfs_sa_upgrade_txholds(tx, zp);
                  error = dmu_tx_assign(tx, TXG_WAIT);
                  if (error) {
                          dmu_tx_abort(tx);
                          if (abuf != NULL)
                                  dmu_return_arcbuf(abuf);
                          break;
                  }
  
                  /*
                   * If zfs_range_lock() over-locked we grow the blocksize
                   * and then reduce the lock range.  This will only happen
                   * on the first iteration since zfs_range_reduce() will
                   * shrink down r_len to the appropriate size.
                   */
                  if (rl->r_len == UINT64_MAX) {
                          uint64_t new_blksz;
  
                          if (zp->z_blksz > max_blksz) {
                                  /*
                                   * File's blocksize is already larger than the
                                   * "recordsize" property.  Only let it grow to
                                   * the next power of 2.
                                   */
                                  ASSERT(!ISP2(zp->z_blksz));
                                  new_blksz = MIN(end_size,
                                      1 << highbit64(zp->z_blksz));
                          } else {
                                  new_blksz = MIN(end_size, max_blksz);
                          }
                          zfs_grow_blocksize(zp, new_blksz, tx);
                          zfs_range_reduce(rl, woff, n);
                  }
  
                  /*
                   * XXX - should we really limit each write to z_max_blksz?
                   * Perhaps we should use SPA_MAXBLOCKSIZE chunks?
                   */
                  nbytes = MIN(n, max_blksz - P2PHASE(woff, max_blksz));
  
                  if (woff + nbytes > zp->z_size)
                          vnode_pager_setsize(vp, woff + nbytes);
  
                  if (abuf == NULL) {
                          tx_bytes = uio->uio_resid;
                          error = dmu_write_uio_dbuf(sa_get_db(zp->z_sa_hdl),
                              uio, nbytes, tx);
                          tx_bytes -= uio->uio_resid;
                  } else {
                          tx_bytes = nbytes;
                          ASSERT(xuio == NULL || tx_bytes == aiov->iov_len);
                          /*
                           * If this is not a full block write, but we are
                           * extending the file past EOF and this data starts
                           * block-aligned, use assign_arcbuf().  Otherwise,
                           * write via dmu_write().
                           */
                          if (tx_bytes < max_blksz && (!write_eof ||
                              aiov->iov_base != abuf->b_data)) {
                                  ASSERT(xuio);
                                  dmu_write(zfsvfs->z_os, zp->z_id, woff,
                                      aiov->iov_len, aiov->iov_base, tx);
                                  dmu_return_arcbuf(abuf);
                                  xuio_stat_wbuf_copied();
                          } else {
                                  ASSERT(xuio || tx_bytes == max_blksz);
                                  dmu_assign_arcbuf(sa_get_db(zp->z_sa_hdl),
                                      woff, abuf, tx);
                          }
                          ASSERT(tx_bytes <= uio->uio_resid);
                          uioskip(uio, tx_bytes);
                  }
                  if (tx_bytes && vn_has_cached_data(vp)) {
                          update_pages(vp, woff, tx_bytes, zfsvfs->z_os,
                              zp->z_id, uio->uio_segflg, tx);
                  }
  
                  /*
                   * If we made no progress, we're done.  If we made even
                   * partial progress, update the znode and ZIL accordingly.
                   */
                  if (tx_bytes == 0) {
                          (void) sa_update(zp->z_sa_hdl, SA_ZPL_SIZE(zfsvfs),
                              (void *)&zp->z_size, sizeof (uint64_t), tx);
                          dmu_tx_commit(tx);
                          ASSERT(error != 0);
                          break;
                  }
  
                  /*
                   * Clear Set-UID/Set-GID bits on successful write if not
                   * privileged and at least one of the excute bits is set.
                   *
                   * It would be nice to to this after all writes have
                   * been done, but that would still expose the ISUID/ISGID
                   * to another app after the partial write is committed.
                   *
                   * Note: we don't call zfs_fuid_map_id() here because
                   * user 0 is not an ephemeral uid.
                   */
                  mutex_enter(&zp->z_acl_lock);
                  if ((zp->z_mode & (S_IXUSR | (S_IXUSR >> 3) |
                      (S_IXUSR >> 6))) != 0 &&
                      (zp->z_mode & (S_ISUID | S_ISGID)) != 0 &&
                      secpolicy_vnode_setid_retain(vp, cr,
                      (zp->z_mode & S_ISUID) != 0 && zp->z_uid == 0) != 0) {
                          uint64_t newmode;
                          zp->z_mode &= ~(S_ISUID | S_ISGID);
                          newmode = zp->z_mode;
                          (void) sa_update(zp->z_sa_hdl, SA_ZPL_MODE(zfsvfs),
                              (void *)&newmode, sizeof (uint64_t), tx);
                  }
                  mutex_exit(&zp->z_acl_lock);
  
                  zfs_tstamp_update_setup(zp, CONTENT_MODIFIED, mtime, ctime,
                      B_TRUE);
  
                  /*
                   * Update the file size (zp_size) if it has changed;
                   * account for possible concurrent updates.
                   */
                  while ((end_size = zp->z_size) < uio->uio_loffset) {
                          (void) atomic_cas_64(&zp->z_size, end_size,
                              uio->uio_loffset);
  #ifdef illumos
                          ASSERT(error == 0);
  #else
                          ASSERT(error == 0 || error == EFAULT);
  #endif
                  }
                  /*
                   * If we are replaying and eof is non zero then force
                   * the file size to the specified eof. Note, there's no
                   * concurrency during replay.
                   */
                  if (zfsvfs->z_replay && zfsvfs->z_replay_eof != 0)
                          zp->z_size = zfsvfs->z_replay_eof;
  
                  if (error == 0)
                          error = sa_bulk_update(zp->z_sa_hdl, bulk, count, tx);
                  else
                          (void) sa_bulk_update(zp->z_sa_hdl, bulk, count, tx);
  
                  zfs_log_write(zilog, tx, TX_WRITE, zp, woff, tx_bytes, ioflag);
                  dmu_tx_commit(tx);
  
                  if (error != 0)
                          break;
                  ASSERT(tx_bytes == nbytes);
                  n -= nbytes;
  
  #ifdef illumos
                  if (!xuio && n > 0)
                          uio_prefaultpages(MIN(n, max_blksz), uio);
  #endif
          }
  
          zfs_range_unlock(rl);
  
          /*
           * If we're in replay mode, or we made no progress, return error.
           * Otherwise, it's at least a partial write, so it's successful.
           */
          if (zfsvfs->z_replay || uio->uio_resid == start_resid) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
  #ifdef __FreeBSD__
          /*
           * EFAULT means that at least one page of the source buffer was not
           * available.  VFS will re-try remaining I/O upon this error.
           */
          if (error == EFAULT) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  #endif
  
          if (ioflag & (FSYNC | FDSYNC) ||
              zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zilog, zp->z_id);
  
          ZFS_EXIT(zfsvfs);
          return (0);
  }
  
  void
  zfs_get_done(zgd_t *zgd, int error)
  {
          znode_t *zp = zgd->zgd_private;
          objset_t *os = zp->z_zfsvfs->z_os;
  
          if (zgd->zgd_db)
                  dmu_buf_rele(zgd->zgd_db, zgd);
  
          zfs_range_unlock(zgd->zgd_rl);
  
          /*
           * Release the vnode asynchronously as we currently have the
           * txg stopped from syncing.
           */
          VN_RELE_ASYNC(ZTOV(zp), dsl_pool_vnrele_taskq(dmu_objset_pool(os)));
  
          if (error == 0 && zgd->zgd_bp)
                  zil_lwb_add_block(zgd->zgd_lwb, zgd->zgd_bp);
  
          kmem_free(zgd, sizeof (zgd_t));
  }
  
  #ifdef DEBUG
  static int zil_fault_io = 0;
  #endif
  
  /*
   * Get data to generate a TX_WRITE intent log record.
   */
  int
  zfs_get_data(void *arg, lr_write_t *lr, char *buf, struct lwb *lwb, zio_t *zio)
  {
          zfsvfs_t *zfsvfs = arg;
          objset_t *os = zfsvfs->z_os;
          znode_t *zp;
          uint64_t object = lr->lr_foid;
          uint64_t offset = lr->lr_offset;
          uint64_t size = lr->lr_length;
          dmu_buf_t *db;
          zgd_t *zgd;
          int error = 0;
  
          ASSERT3P(lwb, !=, NULL);
          ASSERT3P(zio, !=, NULL);
          ASSERT3U(size, !=, 0);
  
          /*
           * Nothing to do if the file has been removed
           */
          if (zfs_zget(zfsvfs, object, &zp) != 0)
                  return (SET_ERROR(ENOENT));
          if (zp->z_unlinked) {
                  /*
                   * Release the vnode asynchronously as we currently have the
                   * txg stopped from syncing.
                   */
                  VN_RELE_ASYNC(ZTOV(zp),
                      dsl_pool_vnrele_taskq(dmu_objset_pool(os)));
                  return (SET_ERROR(ENOENT));
          }
  
          zgd = (zgd_t *)kmem_zalloc(sizeof (zgd_t), KM_SLEEP);
          zgd->zgd_lwb = lwb;
          zgd->zgd_private = zp;
  
          /*
           * Write records come in two flavors: immediate and indirect.
           * For small writes it's cheaper to store the data with the
           * log record (immediate); for large writes it's cheaper to
           * sync the data and get a pointer to it (indirect) so that
           * we don't have to write the data twice.
           */
          if (buf != NULL) { /* immediate write */
                  zgd->zgd_rl = zfs_range_lock(zp, offset, size, RL_READER);
                  /* test for truncation needs to be done while range locked */
                  if (offset >= zp->z_size) {
                          error = SET_ERROR(ENOENT);
                  } else {
                          error = dmu_read(os, object, offset, size, buf,
                              DMU_READ_NO_PREFETCH);
                  }
                  ASSERT(error == 0 || error == ENOENT);
          } else { /* indirect write */
                  /*
                   * Have to lock the whole block to ensure when it's
                   * written out and its checksum is being calculated
                   * that no one can change the data. We need to re-check
                   * blocksize after we get the lock in case it's changed!
                   */
                  for (;;) {
                          uint64_t blkoff;
                          size = zp->z_blksz;
                          blkoff = ISP2(size) ? P2PHASE(offset, size) : offset;
                          offset -= blkoff;
                          zgd->zgd_rl = zfs_range_lock(zp, offset, size,
                              RL_READER);
                          if (zp->z_blksz == size)
                                  break;
                          offset += blkoff;
                          zfs_range_unlock(zgd->zgd_rl);
                  }
                  /* test for truncation needs to be done while range locked */
                  if (lr->lr_offset >= zp->z_size)
                          error = SET_ERROR(ENOENT);
  #ifdef DEBUG
                  if (zil_fault_io) {
                          error = SET_ERROR(EIO);
                          zil_fault_io = 0;
                  }
  #endif
                  if (error == 0)
                          error = dmu_buf_hold(os, object, offset, zgd, &db,
                              DMU_READ_NO_PREFETCH);
  
                  if (error == 0) {
                          blkptr_t *bp = &lr->lr_blkptr;
  
                          zgd->zgd_db = db;
                          zgd->zgd_bp = bp;
  
                          ASSERT(db->db_offset == offset);
                          ASSERT(db->db_size == size);
  
                          error = dmu_sync(zio, lr->lr_common.lrc_txg,
                              zfs_get_done, zgd);
                          ASSERT(error || lr->lr_length <= size);
  
                          /*
                           * On success, we need to wait for the write I/O
                           * initiated by dmu_sync() to complete before we can
                           * release this dbuf.  We will finish everything up
                           * in the zfs_get_done() callback.
                           */
                          if (error == 0)
                                  return (0);
  
                          if (error == EALREADY) {
                                  lr->lr_common.lrc_txtype = TX_WRITE2;
                                  /*
                                   * TX_WRITE2 relies on the data previously
                                   * written by the TX_WRITE that caused
                                   * EALREADY.  We zero out the BP because
                                   * it is the old, currently-on-disk BP,
                                   * so there's no need to zio_flush() its
                                   * vdevs (flushing would needlesly hurt
                                   * performance, and doesn't work on
                                   * indirect vdevs).
                                   */
                                  zgd->zgd_bp = NULL;
                                  BP_ZERO(bp);
                                  error = 0;
                          }
                  }
          }
  
          zfs_get_done(zgd, error);
  
          return (error);
  }
  
  /*ARGSUSED*/
  static int
  zfs_access(vnode_t *vp, int mode, int flag, cred_t *cr,
      caller_context_t *ct)
  {
          znode_t *zp = VTOZ(vp);
          zfsvfs_t *zfsvfs = zp->z_zfsvfs;
          int error;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
  
          if (flag & V_ACE_MASK)
                  error = zfs_zaccess(zp, mode, flag, B_FALSE, cr);
          else
                  error = zfs_zaccess_rwx(zp, mode, flag, cr);
  
          ZFS_EXIT(zfsvfs);
          return (error);
  }
  
  static int
  zfs_dd_callback(struct mount *mp, void *arg, int lkflags, struct vnode **vpp)
  {
          int error;
  
          *vpp = arg;
          error = vn_lock(*vpp, lkflags);
          if (error != 0)
                  vrele(*vpp);
          return (error);
  }
  
  static int
  zfs_lookup_lock(vnode_t *dvp, vnode_t *vp, const char *name, int lkflags)
  {
          znode_t *zdp = VTOZ(dvp);
          zfsvfs_t *zfsvfs = zdp->z_zfsvfs;
          int error;
          int ltype;
  
          ASSERT_VOP_LOCKED(dvp, __func__);
  #ifdef DIAGNOSTIC
          if ((zdp->z_pflags & ZFS_XATTR) == 0)
                  VERIFY(!RRM_LOCK_HELD(&zfsvfs->z_teardown_lock));
  #endif
  
          if (name[0] == 0 || (name[0] == '.' && name[1] == 0)) {
                  ASSERT3P(dvp, ==, vp);
                  vref(dvp);
                  ltype = lkflags & LK_TYPE_MASK;
                  if (ltype != VOP_ISLOCKED(dvp)) {
                          if (ltype == LK_EXCLUSIVE)
                                  vn_lock(dvp, LK_UPGRADE | LK_RETRY);
                          else /* if (ltype == LK_SHARED) */
                                  vn_lock(dvp, LK_DOWNGRADE | LK_RETRY);
  
                          /*
                           * Relock for the "." case could leave us with
                           * reclaimed vnode.
                           */
                          if (dvp->v_iflag & VI_DOOMED) {
                                  vrele(dvp);
                                  return (SET_ERROR(ENOENT));
                          }
                  }
                  return (0);
          } else if (name[0] == '.' && name[1] == '.' && name[2] == 0) {
                  /*
                   * Note that in this case, dvp is the child vnode, and we
                   * are looking up the parent vnode - exactly reverse from
                   * normal operation.  Unlocking dvp requires some rather
                   * tricky unlock/relock dance to prevent mp from being freed;
                   * use vn_vget_ino_gen() which takes care of all that.
                   *
                   * XXX Note that there is a time window when both vnodes are
                   * unlocked.  It is possible, although highly unlikely, that
                   * during that window the parent-child relationship between
                   * the vnodes may change, for example, get reversed.
                   * In that case we would have a wrong lock order for the vnodes.
                   * All other filesystems seem to ignore this problem, so we
                   * do the same here.
                   * A potential solution could be implemented as follows:
                   * - using LK_NOWAIT when locking the second vnode and retrying
                   *   if necessary
                   * - checking that the parent-child relationship still holds
                   *   after locking both vnodes and retrying if it doesn't
                   */
                  error = vn_vget_ino_gen(dvp, zfs_dd_callback, vp, lkflags, &vp);
                  return (error);
          } else {
                  error = vn_lock(vp, lkflags);
                  if (error != 0)
                          vrele(vp);
                  return (error);
          }
  }
  
  /*
   * Lookup an entry in a directory, or an extended attribute directory.
   * If it exists, return a held vnode reference for it.
   *
   *      IN:     dvp     - vnode of directory to search.
   *              nm      - name of entry to lookup.
   *              pnp     - full pathname to lookup [UNUSED].
   *              flags   - LOOKUP_XATTR set if looking for an attribute.
   *              rdir    - root directory vnode [UNUSED].
   *              cr      - credentials of caller.
   *              ct      - caller context
   *
   *      OUT:    vpp     - vnode of located entry, NULL if not found.
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      NA
   */
  /* ARGSUSED */
  static int
  zfs_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, struct componentname *cnp,
      int nameiop, cred_t *cr, kthread_t *td, int flags)
  {
          znode_t *zdp = VTOZ(dvp);
          znode_t *zp;
          zfsvfs_t *zfsvfs = zdp->z_zfsvfs;
          int     error = 0;
  
          /*
           * Fast path lookup, however we must skip DNLC lookup
           * for case folding or normalizing lookups because the
           * DNLC code only stores the passed in name.  This means
           * creating 'a' and removing 'A' on a case insensitive
           * file system would work, but DNLC still thinks 'a'
           * exists and won't let you create it again on the next
           * pass through fast path.
           */
          if (!(flags & LOOKUP_XATTR)) {
                  if (dvp->v_type != VDIR) {
                          return (SET_ERROR(ENOTDIR));
                  } else if (zdp->z_sa_hdl == NULL) {
                          return (SET_ERROR(EIO));
                  }
          }
  
          DTRACE_PROBE2(zfs__fastpath__lookup__miss, vnode_t *, dvp, char *, nm);
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zdp);
  
          *vpp = NULL;
  
          if (flags & LOOKUP_XATTR) {
  #ifdef TODO
                  /*
                   * If the xattr property is off, refuse the lookup request.
                   */
                  if (!(zfsvfs->z_vfs->vfs_flag & VFS_XATTR)) {
                          ZFS_EXIT(zfsvfs);
                          return (SET_ERROR(EINVAL));
                  }
  #endif
  
                  /*
                   * We don't allow recursive attributes..
                   * Maybe someday we will.
                   */
                  if (zdp->z_pflags & ZFS_XATTR) {
                          ZFS_EXIT(zfsvfs);
                          return (SET_ERROR(EINVAL));
                  }
  
                  if (error = zfs_get_xattrdir(VTOZ(dvp), vpp, cr, flags)) {
                          ZFS_EXIT(zfsvfs);
                          return (error);
                  }
  
                  /*
                   * Do we have permission to get into attribute directory?
                   */
                  if (error = zfs_zaccess(VTOZ(*vpp), ACE_EXECUTE, 0,
                      B_FALSE, cr)) {
                          vrele(*vpp);
                          *vpp = NULL;
                  }
  
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          /*
           * Check accessibility of directory.
           */
          if (error = zfs_zaccess(zdp, ACE_EXECUTE, 0, B_FALSE, cr)) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          if (zfsvfs->z_utf8 && u8_validate(nm, strlen(nm),
              NULL, U8_VALIDATE_ENTIRE, &error) < 0) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EILSEQ));
          }
  
  
          /*
           * First handle the special cases.
           */
          if ((cnp->cn_flags & ISDOTDOT) != 0) {
                  /*
                   * If we are a snapshot mounted under .zfs, return
                   * the vp for the snapshot directory.
                   */
                  if (zdp->z_id == zfsvfs->z_root && zfsvfs->z_parent != zfsvfs) {
                          struct componentname cn;
                          vnode_t *zfsctl_vp;
                          int ltype;
  
                          ZFS_EXIT(zfsvfs);
                          ltype = VOP_ISLOCKED(dvp);
                          VOP_UNLOCK(dvp, 0);
                          error = zfsctl_root(zfsvfs->z_parent, LK_SHARED,
                              &zfsctl_vp);
                          if (error == 0) {
                                  cn.cn_nameptr = "snapshot";
                                  cn.cn_namelen = strlen(cn.cn_nameptr);
                                  cn.cn_nameiop = cnp->cn_nameiop;
                                  cn.cn_flags = cnp->cn_flags & ~ISDOTDOT;
                                  cn.cn_lkflags = cnp->cn_lkflags;
                                  error = VOP_LOOKUP(zfsctl_vp, vpp, &cn);
                                  vput(zfsctl_vp);
                          }
                          vn_lock(dvp, ltype | LK_RETRY);
                          return (error);
                  }
          }
          if (zfs_has_ctldir(zdp) && strcmp(nm, ZFS_CTLDIR_NAME) == 0) {
                  ZFS_EXIT(zfsvfs);
                  if ((cnp->cn_flags & ISLASTCN) != 0 && nameiop != LOOKUP)
                          return (SET_ERROR(ENOTSUP));
                  error = zfsctl_root(zfsvfs, cnp->cn_lkflags, vpp);
                  return (error);
          }
  
          /*
           * The loop is retry the lookup if the parent-child relationship
           * changes during the dot-dot locking complexities.
           */
          for (;;) {
                  uint64_t parent;
  
                  error = zfs_dirlook(zdp, nm, &zp);
                  if (error == 0)
                          *vpp = ZTOV(zp);
  
                  ZFS_EXIT(zfsvfs);
                  if (error != 0)
                          break;
  
                  error = zfs_lookup_lock(dvp, *vpp, nm, cnp->cn_lkflags);
                  if (error != 0) {
                          /*
                           * If we've got a locking error, then the vnode
                           * got reclaimed because of a force unmount.
                           * We never enter doomed vnodes into the name cache.
                           */
                          *vpp = NULL;
                          return (error);
                  }
  
                  if ((cnp->cn_flags & ISDOTDOT) == 0)
                          break;
  
                  ZFS_ENTER(zfsvfs);
                  if (zdp->z_sa_hdl == NULL) {
                          error = SET_ERROR(EIO);
                  } else {
                          error = sa_lookup(zdp->z_sa_hdl, SA_ZPL_PARENT(zfsvfs),
                              &parent, sizeof (parent));
                  }
                  if (error != 0) {
                          ZFS_EXIT(zfsvfs);
                          vput(ZTOV(zp));
                          break;
                  }
                  if (zp->z_id == parent) {
                          ZFS_EXIT(zfsvfs);
                          break;
                  }
                  vput(ZTOV(zp));
          }
  
  out:
          if (error != 0)
                  *vpp = NULL;
  
          /* Translate errors and add SAVENAME when needed. */
          if (cnp->cn_flags & ISLASTCN) {
                  switch (nameiop) {
                  case CREATE:
                  case RENAME:
                          if (error == ENOENT) {
                                  error = EJUSTRETURN;
                                  cnp->cn_flags |= SAVENAME;
                                  break;
                          }
                          /* FALLTHROUGH */
                  case DELETE:
                          if (error == 0)
                                  cnp->cn_flags |= SAVENAME;
                          break;
                  }
          }
  
          /* Insert name into cache (as non-existent) if appropriate. */
          if (zfsvfs->z_use_namecache &&
              error == ENOENT && (cnp->cn_flags & MAKEENTRY) != 0)
                  cache_enter(dvp, NULL, cnp);
  
          /* Insert name into cache if appropriate. */
          if (zfsvfs->z_use_namecache &&
              error == 0 && (cnp->cn_flags & MAKEENTRY)) {
                  if (!(cnp->cn_flags & ISLASTCN) ||
                      (nameiop != DELETE && nameiop != RENAME)) {
                          cache_enter(dvp, *vpp, cnp);
                  }
          }
  
          return (error);
  }
  
  /*
   * Attempt to create a new entry in a directory.  If the entry
   * already exists, truncate the file if permissible, else return
   * an error.  Return the vp of the created or trunc'd file.
   *
   *      IN:     dvp     - vnode of directory to put new file entry in.
   *              name    - name of new file entry.
   *              vap     - attributes of new file.
   *              excl    - flag indicating exclusive or non-exclusive mode.
   *              mode    - mode to open file with.
   *              cr      - credentials of caller.
   *              flag    - large file flag [UNUSED].
   *              ct      - caller context
   *              vsecp   - ACL to be set
   *
   *      OUT:    vpp     - vnode of created or trunc'd entry.
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      dvp - ctime|mtime updated if new entry created
   *       vp - ctime|mtime always, atime if new
   */
  
  /* ARGSUSED */
  static int
  zfs_create(vnode_t *dvp, char *name, vattr_t *vap, int excl, int mode,
      vnode_t **vpp, cred_t *cr, kthread_t *td)
  {
          znode_t         *zp, *dzp = VTOZ(dvp);
          zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
          zilog_t         *zilog;
          objset_t        *os;
          dmu_tx_t        *tx;
          int             error;
          ksid_t          *ksid;
          uid_t           uid;
          gid_t           gid = crgetgid(cr);
          zfs_acl_ids_t   acl_ids;
          boolean_t       fuid_dirtied;
          void            *vsecp = NULL;
          int             flag = 0;
          uint64_t        txtype;
  
          /*
           * If we have an ephemeral id, ACL, or XVATTR then
           * make sure file system is at proper version
           */
  
          ksid = crgetsid(cr, KSID_OWNER);
          if (ksid)
                  uid = ksid_getid(ksid);
          else
                  uid = crgetuid(cr);
  
          if (zfsvfs->z_use_fuids == B_FALSE &&
              (vsecp || (vap->va_mask & AT_XVATTR) ||
              IS_EPHEMERAL(uid) || IS_EPHEMERAL(gid)))
                  return (SET_ERROR(EINVAL));
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(dzp);
          os = zfsvfs->z_os;
          zilog = zfsvfs->z_log;
  
          if (zfsvfs->z_utf8 && u8_validate(name, strlen(name),
              NULL, U8_VALIDATE_ENTIRE, &error) < 0) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EILSEQ));
          }
  
          if (vap->va_mask & AT_XVATTR) {
                  if ((error = secpolicy_xvattr(dvp, (xvattr_t *)vap,
                      crgetuid(cr), cr, vap->va_type)) != 0) {
                          ZFS_EXIT(zfsvfs);
                          return (error);
                  }
          }
  
          *vpp = NULL;
  
          if ((vap->va_mode & S_ISVTX) && secpolicy_vnode_stky_modify(cr))
                  vap->va_mode &= ~S_ISVTX;
  
          error = zfs_dirent_lookup(dzp, name, &zp, ZNEW);
          if (error) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
          ASSERT3P(zp, ==, NULL);
  
          /*
           * Create a new file object and update the directory
           * to reference it.
           */
          if (error = zfs_zaccess(dzp, ACE_ADD_FILE, 0, B_FALSE, cr)) {
                  goto out;
          }
  
          /*
           * We only support the creation of regular files in
           * extended attribute directories.
           */
  
          if ((dzp->z_pflags & ZFS_XATTR) &&
              (vap->va_type != VREG)) {
                  error = SET_ERROR(EINVAL);
                  goto out;
          }
  
          if ((error = zfs_acl_ids_create(dzp, 0, vap,
              cr, vsecp, &acl_ids)) != 0)
                  goto out;
  
          if (zfs_acl_ids_overquota(zfsvfs, &acl_ids)) {
                  zfs_acl_ids_free(&acl_ids);
                  error = SET_ERROR(EDQUOT);
                  goto out;
          }
  
          getnewvnode_reserve(1);
  
          tx = dmu_tx_create(os);
  
          dmu_tx_hold_sa_create(tx, acl_ids.z_aclp->z_acl_bytes +
              ZFS_SA_BASE_ATTR_SIZE);
  
          fuid_dirtied = zfsvfs->z_fuid_dirty;
          if (fuid_dirtied)
                  zfs_fuid_txhold(zfsvfs, tx);
          dmu_tx_hold_zap(tx, dzp->z_id, TRUE, name);
          dmu_tx_hold_sa(tx, dzp->z_sa_hdl, B_FALSE);
          if (!zfsvfs->z_use_sa &&
              acl_ids.z_aclp->z_acl_bytes > ZFS_ACE_SPACE) {
                  dmu_tx_hold_write(tx, DMU_NEW_OBJECT,
                      0, acl_ids.z_aclp->z_acl_bytes);
          }
          error = dmu_tx_assign(tx, TXG_WAIT);
          if (error) {
                  zfs_acl_ids_free(&acl_ids);
                  dmu_tx_abort(tx);
                  getnewvnode_drop_reserve();
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
          zfs_mknode(dzp, vap, tx, cr, 0, &zp, &acl_ids);
  
          if (fuid_dirtied)
                  zfs_fuid_sync(zfsvfs, tx);
  
          (void) zfs_link_create(dzp, name, zp, tx, ZNEW);
          txtype = zfs_log_create_txtype(Z_FILE, vsecp, vap);
          zfs_log_create(zilog, tx, txtype, dzp, zp, name,
              vsecp, acl_ids.z_fuidp, vap);
          zfs_acl_ids_free(&acl_ids);
          dmu_tx_commit(tx);
  
          getnewvnode_drop_reserve();
  
  out:
          if (error == 0) {
                  *vpp = ZTOV(zp);
          }
  
          if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zilog, 0);
  
          ZFS_EXIT(zfsvfs);
          return (error);
  }
  
  /*
   * Remove an entry from a directory.
   *
   *      IN:     dvp     - vnode of directory to remove entry from.
   *              name    - name of entry to remove.
   *              cr      - credentials of caller.
   *              ct      - caller context
   *              flags   - case flags
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      dvp - ctime|mtime
   *       vp - ctime (if nlink > 0)
   */
  
  /*ARGSUSED*/
  static int
  zfs_remove(vnode_t *dvp, vnode_t *vp, char *name, cred_t *cr)
  {
          znode_t         *dzp = VTOZ(dvp);
          znode_t         *zp = VTOZ(vp);
          znode_t         *xzp;
          zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
          zilog_t         *zilog;
          uint64_t        acl_obj, xattr_obj;
          uint64_t        obj = 0;
          dmu_tx_t        *tx;
          boolean_t       unlinked, toobig = FALSE;
          uint64_t        txtype;
          int             error;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(dzp);
          ZFS_VERIFY_ZP(zp);
          zilog = zfsvfs->z_log;
          zp = VTOZ(vp);
  
          xattr_obj = 0;
          xzp = NULL;
  
          if (error = zfs_zaccess_delete(dzp, zp, cr)) {
                  goto out;
          }
  
          /*
           * Need to use rmdir for removing directories.
           */
          if (vp->v_type == VDIR) {
                  error = SET_ERROR(EPERM);
                  goto out;
          }
  
          vnevent_remove(vp, dvp, name, ct);
  
          obj = zp->z_id;
  
          /* are there any extended attributes? */
          error = sa_lookup(zp->z_sa_hdl, SA_ZPL_XATTR(zfsvfs),
              &xattr_obj, sizeof (xattr_obj));
          if (error == 0 && xattr_obj) {
                  error = zfs_zget(zfsvfs, xattr_obj, &xzp);
                  ASSERT0(error);
          }
  
          /*
           * We may delete the znode now, or we may put it in the unlinked set;
           * it depends on whether we're the last link, and on whether there are
           * other holds on the vnode.  So we dmu_tx_hold() the right things to
           * allow for either case.
           */
          tx = dmu_tx_create(zfsvfs->z_os);
          dmu_tx_hold_zap(tx, dzp->z_id, FALSE, name);
          dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE);
          zfs_sa_upgrade_txholds(tx, zp);
          zfs_sa_upgrade_txholds(tx, dzp);
  
          if (xzp) {
                  dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_TRUE);
                  dmu_tx_hold_sa(tx, xzp->z_sa_hdl, B_FALSE);
          }
  
          /* charge as an update -- would be nice not to charge at all */
          dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL);
  
          /*
           * Mark this transaction as typically resulting in a net free of space
           */
          dmu_tx_mark_netfree(tx);
  
          error = dmu_tx_assign(tx, TXG_WAIT);
          if (error) {
                  dmu_tx_abort(tx);
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          /*
           * Remove the directory entry.
           */
          error = zfs_link_destroy(dzp, name, zp, tx, ZEXISTS, &unlinked);
  
          if (error) {
                  dmu_tx_commit(tx);
                  goto out;
          }
  
          if (unlinked) {
                  zfs_unlinked_add(zp, tx);
                  vp->v_vflag |= VV_NOSYNC;
          }
  
          txtype = TX_REMOVE;
          zfs_log_remove(zilog, tx, txtype, dzp, name, obj);
  
          dmu_tx_commit(tx);
  out:
  
          if (xzp)
                  vrele(ZTOV(xzp));
  
          if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zilog, 0);
  
          ZFS_EXIT(zfsvfs);
          return (error);
  }
  
  /*
   * Create a new directory and insert it into dvp using the name
   * provided.  Return a pointer to the inserted directory.
   *
   *      IN:     dvp     - vnode of directory to add subdir to.
   *              dirname - name of new directory.
   *              vap     - attributes of new directory.
   *              cr      - credentials of caller.
   *              ct      - caller context
   *              flags   - case flags
   *              vsecp   - ACL to be set
   *
   *      OUT:    vpp     - vnode of created directory.
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      dvp - ctime|mtime updated
   *       vp - ctime|mtime|atime updated
   */
  /*ARGSUSED*/
  static int
  zfs_mkdir(vnode_t *dvp, char *dirname, vattr_t *vap, vnode_t **vpp, cred_t *cr)
  {
          znode_t         *zp, *dzp = VTOZ(dvp);
          zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
          zilog_t         *zilog;
          uint64_t        txtype;
          dmu_tx_t        *tx;
          int             error;
          ksid_t          *ksid;
          uid_t           uid;
          gid_t           gid = crgetgid(cr);
          zfs_acl_ids_t   acl_ids;
          boolean_t       fuid_dirtied;
  
          ASSERT(vap->va_type == VDIR);
  
          /*
           * If we have an ephemeral id, ACL, or XVATTR then
           * make sure file system is at proper version
           */
  
          ksid = crgetsid(cr, KSID_OWNER);
          if (ksid)
                  uid = ksid_getid(ksid);
          else
                  uid = crgetuid(cr);
          if (zfsvfs->z_use_fuids == B_FALSE &&
              ((vap->va_mask & AT_XVATTR) ||
              IS_EPHEMERAL(uid) || IS_EPHEMERAL(gid)))
                  return (SET_ERROR(EINVAL));
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(dzp);
          zilog = zfsvfs->z_log;
  
          if (dzp->z_pflags & ZFS_XATTR) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EINVAL));
          }
  
          if (zfsvfs->z_utf8 && u8_validate(dirname,
              strlen(dirname), NULL, U8_VALIDATE_ENTIRE, &error) < 0) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EILSEQ));
          }
  
          if (vap->va_mask & AT_XVATTR) {
                  if ((error = secpolicy_xvattr(dvp, (xvattr_t *)vap,
                      crgetuid(cr), cr, vap->va_type)) != 0) {
                          ZFS_EXIT(zfsvfs);
                          return (error);
                  }
          }
  
          if ((error = zfs_acl_ids_create(dzp, 0, vap, cr,
              NULL, &acl_ids)) != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          /*
           * First make sure the new directory doesn't exist.
           *
           * Existence is checked first to make sure we don't return
           * EACCES instead of EEXIST which can cause some applications
           * to fail.
           */
          *vpp = NULL;
  
          if (error = zfs_dirent_lookup(dzp, dirname, &zp, ZNEW)) {
                  zfs_acl_ids_free(&acl_ids);
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
          ASSERT3P(zp, ==, NULL);
  
          if (error = zfs_zaccess(dzp, ACE_ADD_SUBDIRECTORY, 0, B_FALSE, cr)) {
                  zfs_acl_ids_free(&acl_ids);
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          if (zfs_acl_ids_overquota(zfsvfs, &acl_ids)) {
                  zfs_acl_ids_free(&acl_ids);
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EDQUOT));
          }
  
          /*
           * Add a new entry to the directory.
           */
          getnewvnode_reserve(1);
          tx = dmu_tx_create(zfsvfs->z_os);
          dmu_tx_hold_zap(tx, dzp->z_id, TRUE, dirname);
          dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
          fuid_dirtied = zfsvfs->z_fuid_dirty;
          if (fuid_dirtied)
                  zfs_fuid_txhold(zfsvfs, tx);
          if (!zfsvfs->z_use_sa && acl_ids.z_aclp->z_acl_bytes > ZFS_ACE_SPACE) {
                  dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
                      acl_ids.z_aclp->z_acl_bytes);
          }
  
          dmu_tx_hold_sa_create(tx, acl_ids.z_aclp->z_acl_bytes +
              ZFS_SA_BASE_ATTR_SIZE);
  
          error = dmu_tx_assign(tx, TXG_WAIT);
          if (error) {
                  zfs_acl_ids_free(&acl_ids);
                  dmu_tx_abort(tx);
                  getnewvnode_drop_reserve();
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          /*
           * Create new node.
           */
          zfs_mknode(dzp, vap, tx, cr, 0, &zp, &acl_ids);
  
          if (fuid_dirtied)
                  zfs_fuid_sync(zfsvfs, tx);
  
          /*
           * Now put new name in parent dir.
           */
          (void) zfs_link_create(dzp, dirname, zp, tx, ZNEW);
  
          *vpp = ZTOV(zp);
  
          txtype = zfs_log_create_txtype(Z_DIR, NULL, vap);
          zfs_log_create(zilog, tx, txtype, dzp, zp, dirname, NULL,
              acl_ids.z_fuidp, vap);
  
          zfs_acl_ids_free(&acl_ids);
  
          dmu_tx_commit(tx);
  
          getnewvnode_drop_reserve();
  
          if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zilog, 0);
  
          ZFS_EXIT(zfsvfs);
          return (0);
  }
  
  /*
   * Remove a directory subdir entry.  If the current working
   * directory is the same as the subdir to be removed, the
   * remove will fail.
   *
   *      IN:     dvp     - vnode of directory to remove from.
   *              name    - name of directory to be removed.
   *              cwd     - vnode of current working directory.
   *              cr      - credentials of caller.
   *              ct      - caller context
   *              flags   - case flags
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      dvp - ctime|mtime updated
   */
  /*ARGSUSED*/
  static int
  zfs_rmdir(vnode_t *dvp, vnode_t *vp, char *name, cred_t *cr)
  {
          znode_t         *dzp = VTOZ(dvp);
          znode_t         *zp = VTOZ(vp);
          zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
          zilog_t         *zilog;
          dmu_tx_t        *tx;
          int             error;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(dzp);
          ZFS_VERIFY_ZP(zp);
          zilog = zfsvfs->z_log;
  
  
          if (error = zfs_zaccess_delete(dzp, zp, cr)) {
                  goto out;
          }
  
          if (vp->v_type != VDIR) {
                  error = SET_ERROR(ENOTDIR);
                  goto out;
          }
  
          vnevent_rmdir(vp, dvp, name, ct);
  
          tx = dmu_tx_create(zfsvfs->z_os);
          dmu_tx_hold_zap(tx, dzp->z_id, FALSE, name);
          dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE);
          dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL);
          zfs_sa_upgrade_txholds(tx, zp);
          zfs_sa_upgrade_txholds(tx, dzp);
          dmu_tx_mark_netfree(tx);
          error = dmu_tx_assign(tx, TXG_WAIT);
          if (error) {
                  dmu_tx_abort(tx);
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          cache_purge(dvp);
  
          error = zfs_link_destroy(dzp, name, zp, tx, ZEXISTS, NULL);
  
          if (error == 0) {
                  uint64_t txtype = TX_RMDIR;
                  zfs_log_remove(zilog, tx, txtype, dzp, name, ZFS_NO_OBJECT);
          }
  
          dmu_tx_commit(tx);
  
          cache_purge(vp);
  out:
          if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zilog, 0);
  
          ZFS_EXIT(zfsvfs);
          return (error);
  }
  
  /*
   * Read as many directory entries as will fit into the provided
   * buffer from the given directory cursor position (specified in
   * the uio structure).
   *
   *      IN:     vp      - vnode of directory to read.
   *              uio     - structure supplying read location, range info,
   *                        and return buffer.
   *              cr      - credentials of caller.
   *              ct      - caller context
   *              flags   - case flags
   *
   *      OUT:    uio     - updated offset and range, buffer filled.
   *              eofp    - set to true if end-of-file detected.
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      vp - atime updated
   *
   * Note that the low 4 bits of the cookie returned by zap is always zero.
   * This allows us to use the low range for "special" directory entries:
   * We use 0 for '.', and 1 for '..'.  If this is the root of the filesystem,
   * we use the offset 2 for the '.zfs' directory.
   */
  /* ARGSUSED */
  static int
  zfs_readdir(vnode_t *vp, uio_t *uio, cred_t *cr, int *eofp, int *ncookies, u_long **cookies)
  {
          znode_t         *zp = VTOZ(vp);
          iovec_t         *iovp;
          edirent_t       *eodp;
          dirent64_t      *odp;
          zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
          objset_t        *os;
          caddr_t         outbuf;
          size_t          bufsize;
          zap_cursor_t    zc;
          zap_attribute_t zap;
          uint_t          bytes_wanted;
          uint64_t        offset; /* must be unsigned; checks for < 1 */
          uint64_t        parent;
          int             local_eof;
          int             outcount;
          int             error;
          uint8_t         prefetch;
          boolean_t       check_sysattrs;
          uint8_t         type;
          int             ncooks;
          u_long          *cooks = NULL;
          int             flags = 0;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
  
          if ((error = sa_lookup(zp->z_sa_hdl, SA_ZPL_PARENT(zfsvfs),
              &parent, sizeof (parent))) != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          /*
           * If we are not given an eof variable,
           * use a local one.
           */
          if (eofp == NULL)
                  eofp = &local_eof;
  
          /*
           * Check for valid iov_len.
           */
          if (uio->uio_iov->iov_len <= 0) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EINVAL));
          }
  
          /*
           * Quit if directory has been removed (posix)
           */
          if ((*eofp = zp->z_unlinked) != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (0);
          }
  
          error = 0;
          os = zfsvfs->z_os;
          offset = uio->uio_loffset;
          prefetch = zp->z_zn_prefetch;
  
          /*
           * Initialize the iterator cursor.
           */
          if (offset <= 3) {
                  /*
                   * Start iteration from the beginning of the directory.
                   */
                  zap_cursor_init(&zc, os, zp->z_id);
          } else {
                  /*
                   * The offset is a serialized cursor.
                   */
                  zap_cursor_init_serialized(&zc, os, zp->z_id, offset);
          }
  
          /*
           * Get space to change directory entries into fs independent format.
           */
          iovp = uio->uio_iov;
          bytes_wanted = iovp->iov_len;
          if (uio->uio_segflg != UIO_SYSSPACE || uio->uio_iovcnt != 1) {
                  bufsize = bytes_wanted;
                  outbuf = kmem_alloc(bufsize, KM_SLEEP);
                  odp = (struct dirent64 *)outbuf;
          } else {
                  bufsize = bytes_wanted;
                  outbuf = NULL;
                  odp = (struct dirent64 *)iovp->iov_base;
          }
          eodp = (struct edirent *)odp;
  
          if (ncookies != NULL) {
                  /*
                   * Minimum entry size is dirent size and 1 byte for a file name.
                   */
                  ncooks = uio->uio_resid / (sizeof(struct dirent) - sizeof(((struct dirent *)NULL)->d_name) + 1);
                  cooks = malloc(ncooks * sizeof(u_long), M_TEMP, M_WAITOK);
                  *cookies = cooks;
                  *ncookies = ncooks;
          }
          /*
           * If this VFS supports the system attribute view interface; and
           * we're looking at an extended attribute directory; and we care
           * about normalization conflicts on this vfs; then we must check
           * for normalization conflicts with the sysattr name space.
           */
  #ifdef TODO
          check_sysattrs = vfs_has_feature(vp->v_vfsp, VFSFT_SYSATTR_VIEWS) &&
              (vp->v_flag & V_XATTRDIR) && zfsvfs->z_norm &&
              (flags & V_RDDIR_ENTFLAGS);
  #else
          check_sysattrs = 0;
  #endif
  
          /*
           * Transform to file-system independent format
           */
          outcount = 0;
          while (outcount < bytes_wanted) {
                  ino64_t objnum;
                  ushort_t reclen;
                  off64_t *next = NULL;
  
                  /*
                   * Special case `.', `..', and `.zfs'.
                   */
                  if (offset == 0) {
                          (void) strcpy(zap.za_name, ".");
                          zap.za_normalization_conflict = 0;
                          objnum = zp->z_id;
                          type = DT_DIR;
                  } else if (offset == 1) {
                          (void) strcpy(zap.za_name, "..");
                          zap.za_normalization_conflict = 0;
                          objnum = parent;
                          type = DT_DIR;
                  } else if (offset == 2 && zfs_show_ctldir(zp)) {
                          (void) strcpy(zap.za_name, ZFS_CTLDIR_NAME);
                          zap.za_normalization_conflict = 0;
                          objnum = ZFSCTL_INO_ROOT;
                          type = DT_DIR;
                  } else {
                          /*
                           * Grab next entry.
                           */
                          if (error = zap_cursor_retrieve(&zc, &zap)) {
                                  if ((*eofp = (error == ENOENT)) != 0)
                                          break;
                                  else
                                          goto update;
                          }
  
                          if (zap.za_integer_length != 8 ||
                              zap.za_num_integers != 1) {
                                  cmn_err(CE_WARN, "zap_readdir: bad directory "
                                      "entry, obj = %lld, offset = %lld\n",
                                      (u_longlong_t)zp->z_id,
                                      (u_longlong_t)offset);
                                  error = SET_ERROR(ENXIO);
                                  goto update;
                          }
  
                          objnum = ZFS_DIRENT_OBJ(zap.za_first_integer);
                          /*
                           * MacOS X can extract the object type here such as:
                           * uint8_t type = ZFS_DIRENT_TYPE(zap.za_first_integer);
                           */
                          type = ZFS_DIRENT_TYPE(zap.za_first_integer);
  
                          if (check_sysattrs && !zap.za_normalization_conflict) {
  #ifdef TODO
                                  zap.za_normalization_conflict =
                                      xattr_sysattr_casechk(zap.za_name);
  #else
                                  panic("%s:%u: TODO", __func__, __LINE__);
  #endif
                          }
                  }
  
                  if (flags & V_RDDIR_ACCFILTER) {
                          /*
                           * If we have no access at all, don't include
                           * this entry in the returned information
                           */
                          znode_t *ezp;
                          if (zfs_zget(zp->z_zfsvfs, objnum, &ezp) != 0)
                                  goto skip_entry;
                          if (!zfs_has_access(ezp, cr)) {
                                  vrele(ZTOV(ezp));
                                  goto skip_entry;
                          }
                          vrele(ZTOV(ezp));
                  }
  
                  if (flags & V_RDDIR_ENTFLAGS)
                          reclen = EDIRENT_RECLEN(strlen(zap.za_name));
                  else
                          reclen = DIRENT64_RECLEN(strlen(zap.za_name));
  
                  /*
                   * Will this entry fit in the buffer?
                   */
                  if (outcount + reclen > bufsize) {
                          /*
                           * Did we manage to fit anything in the buffer?
                           */
                          if (!outcount) {
                                  error = SET_ERROR(EINVAL);
                                  goto update;
                          }
                          break;
                  }
                  if (flags & V_RDDIR_ENTFLAGS) {
                          /*
                           * Add extended flag entry:
                           */
                          eodp->ed_ino = objnum;
                          eodp->ed_reclen = reclen;
                          /* NOTE: ed_off is the offset for the *next* entry. */
                          next = &eodp->ed_off;
                          eodp->ed_eflags = zap.za_normalization_conflict ?
                              ED_CASE_CONFLICT : 0;
                          (void) strncpy(eodp->ed_name, zap.za_name,
                              EDIRENT_NAMELEN(reclen));
                          eodp = (edirent_t *)((intptr_t)eodp + reclen);
                  } else {
                          /*
                           * Add normal entry:
                           */
                          odp->d_ino = objnum;
                          odp->d_reclen = reclen;
                          odp->d_namlen = strlen(zap.za_name);
                          /* NOTE: d_off is the offset for the *next* entry. */
                          next = &odp->d_off;
                          (void) strlcpy(odp->d_name, zap.za_name, odp->d_namlen + 1);
                          odp->d_type = type;
                          dirent_terminate(odp);
                          odp = (dirent64_t *)((intptr_t)odp + reclen);
                  }
                  outcount += reclen;
  
                  ASSERT(outcount <= bufsize);
  
                  /* Prefetch znode */
                  if (prefetch)
                          dmu_prefetch(os, objnum, 0, 0, 0,
                              ZIO_PRIORITY_SYNC_READ);
  
          skip_entry:
                  /*
                   * Move to the next entry, fill in the previous offset.
                   */
                  if (offset > 2 || (offset == 2 && !zfs_show_ctldir(zp))) {
                          zap_cursor_advance(&zc);
                          offset = zap_cursor_serialize(&zc);
                  } else {
                          offset += 1;
                  }
  
                  /* Fill the offset right after advancing the cursor. */
                  if (next != NULL)
                          *next = offset;
                  if (cooks != NULL) {
                          *cooks++ = offset;
                          ncooks--;
                          KASSERT(ncooks >= 0, ("ncookies=%d", ncooks));
                  }
          }
          zp->z_zn_prefetch = B_FALSE; /* a lookup will re-enable pre-fetching */
  
          /* Subtract unused cookies */
          if (ncookies != NULL)
                  *ncookies -= ncooks;
  
          if (uio->uio_segflg == UIO_SYSSPACE && uio->uio_iovcnt == 1) {
                  iovp->iov_base += outcount;
                  iovp->iov_len -= outcount;
                  uio->uio_resid -= outcount;
          } else if (error = uiomove(outbuf, (long)outcount, UIO_READ, uio)) {
                  /*
                   * Reset the pointer.
                   */
                  offset = uio->uio_loffset;
          }
  
  update:
          zap_cursor_fini(&zc);
          if (uio->uio_segflg != UIO_SYSSPACE || uio->uio_iovcnt != 1)
                  kmem_free(outbuf, bufsize);
  
          if (error == ENOENT)
                  error = 0;
  
          ZFS_ACCESSTIME_STAMP(zfsvfs, zp);
  
          uio->uio_loffset = offset;
          ZFS_EXIT(zfsvfs);
          if (error != 0 && cookies != NULL) {
                  free(*cookies, M_TEMP);
                  *cookies = NULL;
                  *ncookies = 0;
          }
          return (error);
  }
  
  ulong_t zfs_fsync_sync_cnt = 4;
  
  static int
  zfs_fsync(vnode_t *vp, int syncflag, cred_t *cr, caller_context_t *ct)
  {
          znode_t *zp = VTOZ(vp);
          zfsvfs_t *zfsvfs = zp->z_zfsvfs;
  
          (void) tsd_set(zfs_fsyncer_key, (void *)zfs_fsync_sync_cnt);
  
          if (zfsvfs->z_os->os_sync != ZFS_SYNC_DISABLED) {
                  ZFS_ENTER(zfsvfs);
                  ZFS_VERIFY_ZP(zp);
                  zil_commit(zfsvfs->z_log, zp->z_id);
                  ZFS_EXIT(zfsvfs);
          }
          return (0);
  }
  
  
  /*
   * Get the requested file attributes and place them in the provided
   * vattr structure.
   *
   *      IN:     vp      - vnode of file.
   *              vap     - va_mask identifies requested attributes.
   *                        If AT_XVATTR set, then optional attrs are requested
   *              flags   - ATTR_NOACLCHECK (CIFS server context)
   *              cr      - credentials of caller.
   *              ct      - caller context
   *
   *      OUT:    vap     - attribute values.
   *
   *      RETURN: 0 (always succeeds).
   */
  /* ARGSUSED */
  static int
  zfs_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
      caller_context_t *ct)
  {
          znode_t *zp = VTOZ(vp);
          zfsvfs_t *zfsvfs = zp->z_zfsvfs;
          int     error = 0;
          uint32_t blksize;
          u_longlong_t nblocks;
          uint64_t mtime[2], ctime[2], crtime[2], rdev;
          xvattr_t *xvap = (xvattr_t *)vap;       /* vap may be an xvattr_t * */
          xoptattr_t *xoap = NULL;
          boolean_t skipaclchk = (flags & ATTR_NOACLCHECK) ? B_TRUE : B_FALSE;
          sa_bulk_attr_t bulk[4];
          int count = 0;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
  
          zfs_fuid_map_ids(zp, cr, &vap->va_uid, &vap->va_gid);
  
          SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs), NULL, &mtime, 16);
          SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL, &ctime, 16);
          SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CRTIME(zfsvfs), NULL, &crtime, 16);
          if (vp->v_type == VBLK || vp->v_type == VCHR)
                  SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_RDEV(zfsvfs), NULL,
                      &rdev, 8);
  
          if ((error = sa_bulk_lookup(zp->z_sa_hdl, bulk, count)) != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          /*
           * If ACL is trivial don't bother looking for ACE_READ_ATTRIBUTES.
           * Also, if we are the owner don't bother, since owner should
           * always be allowed to read basic attributes of file.
           */
          if (!(zp->z_pflags & ZFS_ACL_TRIVIAL) &&
              (vap->va_uid != crgetuid(cr))) {
                  if (error = zfs_zaccess(zp, ACE_READ_ATTRIBUTES, 0,
                      skipaclchk, cr)) {
                          ZFS_EXIT(zfsvfs);
                          return (error);
                  }
          }
  
          /*
           * Return all attributes.  It's cheaper to provide the answer
           * than to determine whether we were asked the question.
           */
  
          vap->va_type = IFTOVT(zp->z_mode);
          vap->va_mode = zp->z_mode & ~S_IFMT;
  #ifdef illumos
          vap->va_fsid = zp->z_zfsvfs->z_vfs->vfs_dev;
  #else
          vn_fsid(vp, vap);
  #endif
          vap->va_nodeid = zp->z_id;
          vap->va_nlink = zp->z_links;
          if ((vp->v_flag & VROOT) && zfs_show_ctldir(zp) &&
              zp->z_links < ZFS_LINK_MAX)
                  vap->va_nlink++;
          vap->va_size = zp->z_size;
  #ifdef illumos
          vap->va_rdev = vp->v_rdev;
  #else
          if (vp->v_type == VBLK || vp->v_type == VCHR)
                  vap->va_rdev = zfs_cmpldev(rdev);
  #endif
          vap->va_seq = zp->z_seq;
          vap->va_flags = 0;      /* FreeBSD: Reset chflags(2) flags. */
          vap->va_filerev = zp->z_seq;
  
          /*
           * Add in any requested optional attributes and the create time.
           * Also set the corresponding bits in the returned attribute bitmap.
           */
          if ((xoap = xva_getxoptattr(xvap)) != NULL && zfsvfs->z_use_fuids) {
                  if (XVA_ISSET_REQ(xvap, XAT_ARCHIVE)) {
                          xoap->xoa_archive =
                              ((zp->z_pflags & ZFS_ARCHIVE) != 0);
                          XVA_SET_RTN(xvap, XAT_ARCHIVE);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_READONLY)) {
                          xoap->xoa_readonly =
                              ((zp->z_pflags & ZFS_READONLY) != 0);
                          XVA_SET_RTN(xvap, XAT_READONLY);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_SYSTEM)) {
                          xoap->xoa_system =
                              ((zp->z_pflags & ZFS_SYSTEM) != 0);
                          XVA_SET_RTN(xvap, XAT_SYSTEM);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_HIDDEN)) {
                          xoap->xoa_hidden =
                              ((zp->z_pflags & ZFS_HIDDEN) != 0);
                          XVA_SET_RTN(xvap, XAT_HIDDEN);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_NOUNLINK)) {
                          xoap->xoa_nounlink =
                              ((zp->z_pflags & ZFS_NOUNLINK) != 0);
                          XVA_SET_RTN(xvap, XAT_NOUNLINK);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_IMMUTABLE)) {
                          xoap->xoa_immutable =
                              ((zp->z_pflags & ZFS_IMMUTABLE) != 0);
                          XVA_SET_RTN(xvap, XAT_IMMUTABLE);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_APPENDONLY)) {
                          xoap->xoa_appendonly =
                              ((zp->z_pflags & ZFS_APPENDONLY) != 0);
                          XVA_SET_RTN(xvap, XAT_APPENDONLY);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_NODUMP)) {
                          xoap->xoa_nodump =
                              ((zp->z_pflags & ZFS_NODUMP) != 0);
                          XVA_SET_RTN(xvap, XAT_NODUMP);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_OPAQUE)) {
                          xoap->xoa_opaque =
                              ((zp->z_pflags & ZFS_OPAQUE) != 0);
                          XVA_SET_RTN(xvap, XAT_OPAQUE);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_AV_QUARANTINED)) {
                          xoap->xoa_av_quarantined =
                              ((zp->z_pflags & ZFS_AV_QUARANTINED) != 0);
                          XVA_SET_RTN(xvap, XAT_AV_QUARANTINED);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_AV_MODIFIED)) {
                          xoap->xoa_av_modified =
                              ((zp->z_pflags & ZFS_AV_MODIFIED) != 0);
                          XVA_SET_RTN(xvap, XAT_AV_MODIFIED);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_AV_SCANSTAMP) &&
                      vp->v_type == VREG) {
                          zfs_sa_get_scanstamp(zp, xvap);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_REPARSE)) {
                          xoap->xoa_reparse = ((zp->z_pflags & ZFS_REPARSE) != 0);
                          XVA_SET_RTN(xvap, XAT_REPARSE);
                  }
                  if (XVA_ISSET_REQ(xvap, XAT_GEN)) {
                          xoap->xoa_generation = zp->z_gen;
                          XVA_SET_RTN(xvap, XAT_GEN);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_OFFLINE)) {
                          xoap->xoa_offline =
                              ((zp->z_pflags & ZFS_OFFLINE) != 0);
                          XVA_SET_RTN(xvap, XAT_OFFLINE);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_SPARSE)) {
                          xoap->xoa_sparse =
                              ((zp->z_pflags & ZFS_SPARSE) != 0);
                          XVA_SET_RTN(xvap, XAT_SPARSE);
                  }
          }
  
          ZFS_TIME_DECODE(&vap->va_atime, zp->z_atime);
          ZFS_TIME_DECODE(&vap->va_mtime, mtime);
          ZFS_TIME_DECODE(&vap->va_ctime, ctime);
          ZFS_TIME_DECODE(&vap->va_birthtime, crtime);
  
  
          sa_object_size(zp->z_sa_hdl, &blksize, &nblocks);
          vap->va_blksize = blksize;
          vap->va_bytes = nblocks << 9;   /* nblocks * 512 */
  
          if (zp->z_blksz == 0) {
                  /*
                   * Block size hasn't been set; suggest maximal I/O transfers.
                   */
                  vap->va_blksize = zfsvfs->z_max_blksz;
          }
  
          ZFS_EXIT(zfsvfs);
          return (0);
  }
  
  /*
   * Set the file attributes to the values contained in the
   * vattr structure.
   *
   *      IN:     vp      - vnode of file to be modified.
   *              vap     - new attribute values.
   *                        If AT_XVATTR set, then optional attrs are being set
   *              flags   - ATTR_UTIME set if non-default time values provided.
   *                      - ATTR_NOACLCHECK (CIFS context only).
   *              cr      - credentials of caller.
   *              ct      - caller context
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      vp - ctime updated, mtime updated if size changed.
   */
  /* ARGSUSED */
  static int
  zfs_setattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
      caller_context_t *ct)
  {
          znode_t         *zp = VTOZ(vp);
          zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
          zilog_t         *zilog;
          dmu_tx_t        *tx;
          vattr_t         oldva;
          xvattr_t        tmpxvattr;
          uint_t          mask = vap->va_mask;
          uint_t          saved_mask = 0;
          uint64_t        saved_mode;
          int             trim_mask = 0;
          uint64_t        new_mode;
          uint64_t        new_uid, new_gid;
          uint64_t        xattr_obj;
          uint64_t        mtime[2], ctime[2];
          znode_t         *attrzp;
          int             need_policy = FALSE;
          int             err, err2;
          zfs_fuid_info_t *fuidp = NULL;
          xvattr_t *xvap = (xvattr_t *)vap;       /* vap may be an xvattr_t * */
          xoptattr_t      *xoap;
          zfs_acl_t       *aclp;
          boolean_t skipaclchk = (flags & ATTR_NOACLCHECK) ? B_TRUE : B_FALSE;
          boolean_t       fuid_dirtied = B_FALSE;
          sa_bulk_attr_t  bulk[7], xattr_bulk[7];
          int             count = 0, xattr_count = 0;
  
          if (mask == 0)
                  return (0);
  
          if (mask & AT_NOSET)
                  return (SET_ERROR(EINVAL));
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
  
          zilog = zfsvfs->z_log;
  
          /*
           * Make sure that if we have ephemeral uid/gid or xvattr specified
           * that file system is at proper version level
           */
  
          if (zfsvfs->z_use_fuids == B_FALSE &&
              (((mask & AT_UID) && IS_EPHEMERAL(vap->va_uid)) ||
              ((mask & AT_GID) && IS_EPHEMERAL(vap->va_gid)) ||
              (mask & AT_XVATTR))) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EINVAL));
          }
  
          if (mask & AT_SIZE && vp->v_type == VDIR) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EISDIR));
          }
  
          if (mask & AT_SIZE && vp->v_type != VREG && vp->v_type != VFIFO) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EINVAL));
          }
  
          /*
           * If this is an xvattr_t, then get a pointer to the structure of
           * optional attributes.  If this is NULL, then we have a vattr_t.
           */
          xoap = xva_getxoptattr(xvap);
  
          xva_init(&tmpxvattr);
  
          /*
           * Immutable files can only alter immutable bit and atime
           */
          if ((zp->z_pflags & ZFS_IMMUTABLE) &&
              ((mask & (AT_SIZE|AT_UID|AT_GID|AT_MTIME|AT_MODE)) ||
              ((mask & AT_XVATTR) && XVA_ISSET_REQ(xvap, XAT_CREATETIME)))) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EPERM));
          }
  
          /*
           * Note: ZFS_READONLY is handled in zfs_zaccess_common.
           */
  
          /*
           * Verify timestamps doesn't overflow 32 bits.
           * ZFS can handle large timestamps, but 32bit syscalls can't
           * handle times greater than 2039.  This check should be removed
           * once large timestamps are fully supported.
           */
          if (mask & (AT_ATIME | AT_MTIME)) {
                  if (((mask & AT_ATIME) && TIMESPEC_OVERFLOW(&vap->va_atime)) ||
                      ((mask & AT_MTIME) && TIMESPEC_OVERFLOW(&vap->va_mtime))) {
                          ZFS_EXIT(zfsvfs);
                          return (SET_ERROR(EOVERFLOW));
                  }
          }
          if (xoap && (mask & AT_XVATTR) && XVA_ISSET_REQ(xvap, XAT_CREATETIME) &&
              TIMESPEC_OVERFLOW(&vap->va_birthtime)) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EOVERFLOW));
          }
  
          attrzp = NULL;
          aclp = NULL;
  
          /* Can this be moved to before the top label? */
          if (zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EROFS));
          }
  
          /*
           * First validate permissions
           */
  
          if (mask & AT_SIZE) {
                  /*
                   * XXX - Note, we are not providing any open
                   * mode flags here (like FNDELAY), so we may
                   * block if there are locks present... this
                   * should be addressed in openat().
                   */
                  /* XXX - would it be OK to generate a log record here? */
                  err = zfs_freesp(zp, vap->va_size, 0, 0, FALSE);
                  if (err) {
                          ZFS_EXIT(zfsvfs);
                          return (err);
                  }
          }
  
          if (mask & (AT_ATIME|AT_MTIME) ||
              ((mask & AT_XVATTR) && (XVA_ISSET_REQ(xvap, XAT_HIDDEN) ||
              XVA_ISSET_REQ(xvap, XAT_READONLY) ||
              XVA_ISSET_REQ(xvap, XAT_ARCHIVE) ||
              XVA_ISSET_REQ(xvap, XAT_OFFLINE) ||
              XVA_ISSET_REQ(xvap, XAT_SPARSE) ||
              XVA_ISSET_REQ(xvap, XAT_CREATETIME) ||
              XVA_ISSET_REQ(xvap, XAT_SYSTEM)))) {
                  need_policy = zfs_zaccess(zp, ACE_WRITE_ATTRIBUTES, 0,
                      skipaclchk, cr);
          }
  
          if (mask & (AT_UID|AT_GID)) {
                  int     idmask = (mask & (AT_UID|AT_GID));
                  int     take_owner;
                  int     take_group;
  
                  /*
                   * NOTE: even if a new mode is being set,
                   * we may clear S_ISUID/S_ISGID bits.
                   */
  
                  if (!(mask & AT_MODE))
                          vap->va_mode = zp->z_mode;
  
                  /*
                   * Take ownership or chgrp to group we are a member of
                   */
  
                  take_owner = (mask & AT_UID) && (vap->va_uid == crgetuid(cr));
                  take_group = (mask & AT_GID) &&
                      zfs_groupmember(zfsvfs, vap->va_gid, cr);
  
                  /*
                   * If both AT_UID and AT_GID are set then take_owner and
                   * take_group must both be set in order to allow taking
                   * ownership.
                   *
                   * Otherwise, send the check through secpolicy_vnode_setattr()
                   *
                   */
  
                  if (((idmask == (AT_UID|AT_GID)) && take_owner && take_group) ||
                      ((idmask == AT_UID) && take_owner) ||
                      ((idmask == AT_GID) && take_group)) {
                          if (zfs_zaccess(zp, ACE_WRITE_OWNER, 0,
                              skipaclchk, cr) == 0) {
                                  /*
                                   * Remove setuid/setgid for non-privileged users
                                   */
                                  secpolicy_setid_clear(vap, vp, cr);
                                  trim_mask = (mask & (AT_UID|AT_GID));
                          } else {
                                  need_policy =  TRUE;
                          }
                  } else {
                          need_policy =  TRUE;
                  }
          }
  
          oldva.va_mode = zp->z_mode;
          zfs_fuid_map_ids(zp, cr, &oldva.va_uid, &oldva.va_gid);
          if (mask & AT_XVATTR) {
                  /*
                   * Update xvattr mask to include only those attributes
                   * that are actually changing.
                   *
                   * the bits will be restored prior to actually setting
                   * the attributes so the caller thinks they were set.
                   */
                  if (XVA_ISSET_REQ(xvap, XAT_APPENDONLY)) {
                          if (xoap->xoa_appendonly !=
                              ((zp->z_pflags & ZFS_APPENDONLY) != 0)) {
                                  need_policy = TRUE;
                          } else {
                                  XVA_CLR_REQ(xvap, XAT_APPENDONLY);
                                  XVA_SET_REQ(&tmpxvattr, XAT_APPENDONLY);
                          }
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_NOUNLINK)) {
                          if (xoap->xoa_nounlink !=
                              ((zp->z_pflags & ZFS_NOUNLINK) != 0)) {
                                  need_policy = TRUE;
                          } else {
                                  XVA_CLR_REQ(xvap, XAT_NOUNLINK);
                                  XVA_SET_REQ(&tmpxvattr, XAT_NOUNLINK);
                          }
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_IMMUTABLE)) {
                          if (xoap->xoa_immutable !=
                              ((zp->z_pflags & ZFS_IMMUTABLE) != 0)) {
                                  need_policy = TRUE;
                          } else {
                                  XVA_CLR_REQ(xvap, XAT_IMMUTABLE);
                                  XVA_SET_REQ(&tmpxvattr, XAT_IMMUTABLE);
                          }
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_NODUMP)) {
                          if (xoap->xoa_nodump !=
                              ((zp->z_pflags & ZFS_NODUMP) != 0)) {
                                  need_policy = TRUE;
                          } else {
                                  XVA_CLR_REQ(xvap, XAT_NODUMP);
                                  XVA_SET_REQ(&tmpxvattr, XAT_NODUMP);
                          }
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_AV_MODIFIED)) {
                          if (xoap->xoa_av_modified !=
                              ((zp->z_pflags & ZFS_AV_MODIFIED) != 0)) {
                                  need_policy = TRUE;
                          } else {
                                  XVA_CLR_REQ(xvap, XAT_AV_MODIFIED);
                                  XVA_SET_REQ(&tmpxvattr, XAT_AV_MODIFIED);
                          }
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_AV_QUARANTINED)) {
                          if ((vp->v_type != VREG &&
                              xoap->xoa_av_quarantined) ||
                              xoap->xoa_av_quarantined !=
                              ((zp->z_pflags & ZFS_AV_QUARANTINED) != 0)) {
                                  need_policy = TRUE;
                          } else {
                                  XVA_CLR_REQ(xvap, XAT_AV_QUARANTINED);
                                  XVA_SET_REQ(&tmpxvattr, XAT_AV_QUARANTINED);
                          }
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_REPARSE)) {
                          ZFS_EXIT(zfsvfs);
                          return (SET_ERROR(EPERM));
                  }
  
                  if (need_policy == FALSE &&
                      (XVA_ISSET_REQ(xvap, XAT_AV_SCANSTAMP) ||
                      XVA_ISSET_REQ(xvap, XAT_OPAQUE))) {
                          need_policy = TRUE;
                  }
          }
  
          if (mask & AT_MODE) {
                  if (zfs_zaccess(zp, ACE_WRITE_ACL, 0, skipaclchk, cr) == 0) {
                          err = secpolicy_setid_setsticky_clear(vp, vap,
                              &oldva, cr);
                          if (err) {
                                  ZFS_EXIT(zfsvfs);
                                  return (err);
                          }
                          trim_mask |= AT_MODE;
                  } else {
                          need_policy = TRUE;
                  }
          }
  
          if (need_policy) {
                  /*
                   * If trim_mask is set then take ownership
                   * has been granted or write_acl is present and user
                   * has the ability to modify mode.  In that case remove
                   * UID|GID and or MODE from mask so that
                   * secpolicy_vnode_setattr() doesn't revoke it.
                   */
  
                  if (trim_mask) {
                          saved_mask = vap->va_mask;
                          vap->va_mask &= ~trim_mask;
                          if (trim_mask & AT_MODE) {
                                  /*
                                   * Save the mode, as secpolicy_vnode_setattr()
                                   * will overwrite it with ova.va_mode.
                                   */
                                  saved_mode = vap->va_mode;
                          }
                  }
                  err = secpolicy_vnode_setattr(cr, vp, vap, &oldva, flags,
                      (int (*)(void *, int, cred_t *))zfs_zaccess_unix, zp);
                  if (err) {
                          ZFS_EXIT(zfsvfs);
                          return (err);
                  }
  
                  if (trim_mask) {
                          vap->va_mask |= saved_mask;
                          if (trim_mask & AT_MODE) {
                                  /*
                                   * Recover the mode after
                                   * secpolicy_vnode_setattr().
                                   */
                                  vap->va_mode = saved_mode;
                          }
                  }
          }
  
          /*
           * secpolicy_vnode_setattr, or take ownership may have
           * changed va_mask
           */
          mask = vap->va_mask;
  
          if ((mask & (AT_UID | AT_GID))) {
                  err = sa_lookup(zp->z_sa_hdl, SA_ZPL_XATTR(zfsvfs),
                      &xattr_obj, sizeof (xattr_obj));
  
                  if (err == 0 && xattr_obj) {
                          err = zfs_zget(zp->z_zfsvfs, xattr_obj, &attrzp);
                          if (err == 0) {
                                  err = vn_lock(ZTOV(attrzp), LK_EXCLUSIVE);
                                  if (err != 0)
                                          vrele(ZTOV(attrzp));
                          }
                          if (err)
                                  goto out2;
                  }
                  if (mask & AT_UID) {
                          new_uid = zfs_fuid_create(zfsvfs,
                              (uint64_t)vap->va_uid, cr, ZFS_OWNER, &fuidp);
                          if (new_uid != zp->z_uid &&
                              zfs_fuid_overquota(zfsvfs, B_FALSE, new_uid)) {
                                  if (attrzp)
                                          vput(ZTOV(attrzp));
                                  err = SET_ERROR(EDQUOT);
                                  goto out2;
                          }
                  }
  
                  if (mask & AT_GID) {
                          new_gid = zfs_fuid_create(zfsvfs, (uint64_t)vap->va_gid,
                              cr, ZFS_GROUP, &fuidp);
                          if (new_gid != zp->z_gid &&
                              zfs_fuid_overquota(zfsvfs, B_TRUE, new_gid)) {
                                  if (attrzp)
                                          vput(ZTOV(attrzp));
                                  err = SET_ERROR(EDQUOT);
                                  goto out2;
                          }
                  }
          }
          tx = dmu_tx_create(zfsvfs->z_os);
  
          if (mask & AT_MODE) {
                  uint64_t pmode = zp->z_mode;
                  uint64_t acl_obj;
                  new_mode = (pmode & S_IFMT) | (vap->va_mode & ~S_IFMT);
  
                  if (zp->z_zfsvfs->z_acl_mode == ZFS_ACL_RESTRICTED &&
                      !(zp->z_pflags & ZFS_ACL_TRIVIAL)) {
                          err = SET_ERROR(EPERM);
                          goto out;
                  }
  
                  if (err = zfs_acl_chmod_setattr(zp, &aclp, new_mode))
                          goto out;
  
                  if (!zp->z_is_sa && ((acl_obj = zfs_external_acl(zp)) != 0)) {
                          /*
                           * Are we upgrading ACL from old V0 format
                           * to V1 format?
                           */
                          if (zfsvfs->z_version >= ZPL_VERSION_FUID &&
                              zfs_znode_acl_version(zp) ==
                              ZFS_ACL_VERSION_INITIAL) {
                                  dmu_tx_hold_free(tx, acl_obj, 0,
                                      DMU_OBJECT_END);
                                  dmu_tx_hold_write(tx, DMU_NEW_OBJECT,
                                      0, aclp->z_acl_bytes);
                          } else {
                                  dmu_tx_hold_write(tx, acl_obj, 0,
                                      aclp->z_acl_bytes);
                          }
                  } else if (!zp->z_is_sa && aclp->z_acl_bytes > ZFS_ACE_SPACE) {
                          dmu_tx_hold_write(tx, DMU_NEW_OBJECT,
                              0, aclp->z_acl_bytes);
                  }
                  dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_TRUE);
          } else {
                  if ((mask & AT_XVATTR) &&
                      XVA_ISSET_REQ(xvap, XAT_AV_SCANSTAMP))
                          dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_TRUE);
                  else
                          dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE);
          }
  
          if (attrzp) {
                  dmu_tx_hold_sa(tx, attrzp->z_sa_hdl, B_FALSE);
          }
  
          fuid_dirtied = zfsvfs->z_fuid_dirty;
          if (fuid_dirtied)
                  zfs_fuid_txhold(zfsvfs, tx);
  
          zfs_sa_upgrade_txholds(tx, zp);
  
          err = dmu_tx_assign(tx, TXG_WAIT);
          if (err)
                  goto out;
  
          count = 0;
          /*
           * Set each attribute requested.
           * We group settings according to the locks they need to acquire.
           *
           * Note: you cannot set ctime directly, although it will be
           * updated as a side-effect of calling this function.
           */
  
          if (mask & (AT_UID|AT_GID|AT_MODE))
                  mutex_enter(&zp->z_acl_lock);
  
          SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
              &zp->z_pflags, sizeof (zp->z_pflags));
  
          if (attrzp) {
                  if (mask & (AT_UID|AT_GID|AT_MODE))
                          mutex_enter(&attrzp->z_acl_lock);
                  SA_ADD_BULK_ATTR(xattr_bulk, xattr_count,
                      SA_ZPL_FLAGS(zfsvfs), NULL, &attrzp->z_pflags,
                      sizeof (attrzp->z_pflags));
          }
  
          if (mask & (AT_UID|AT_GID)) {
  
                  if (mask & AT_UID) {
                          SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_UID(zfsvfs), NULL,
                              &new_uid, sizeof (new_uid));
                          zp->z_uid = new_uid;
                          if (attrzp) {
                                  SA_ADD_BULK_ATTR(xattr_bulk, xattr_count,
                                      SA_ZPL_UID(zfsvfs), NULL, &new_uid,
                                      sizeof (new_uid));
                                  attrzp->z_uid = new_uid;
                          }
                  }
  
                  if (mask & AT_GID) {
                          SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_GID(zfsvfs),
                              NULL, &new_gid, sizeof (new_gid));
                          zp->z_gid = new_gid;
                          if (attrzp) {
                                  SA_ADD_BULK_ATTR(xattr_bulk, xattr_count,
                                      SA_ZPL_GID(zfsvfs), NULL, &new_gid,
                                      sizeof (new_gid));
                                  attrzp->z_gid = new_gid;
                          }
                  }
                  if (!(mask & AT_MODE)) {
                          SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MODE(zfsvfs),
                              NULL, &new_mode, sizeof (new_mode));
                          new_mode = zp->z_mode;
                  }
                  err = zfs_acl_chown_setattr(zp);
                  ASSERT(err == 0);
                  if (attrzp) {
                          err = zfs_acl_chown_setattr(attrzp);
                          ASSERT(err == 0);
                  }
          }
  
          if (mask & AT_MODE) {
                  SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MODE(zfsvfs), NULL,
                      &new_mode, sizeof (new_mode));
                  zp->z_mode = new_mode;
                  ASSERT3U((uintptr_t)aclp, !=, 0);
                  err = zfs_aclset_common(zp, aclp, cr, tx);
                  ASSERT0(err);
                  if (zp->z_acl_cached)
                          zfs_acl_free(zp->z_acl_cached);
                  zp->z_acl_cached = aclp;
                  aclp = NULL;
          }
  
  
          if (mask & AT_ATIME) {
                  ZFS_TIME_ENCODE(&vap->va_atime, zp->z_atime);
                  SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_ATIME(zfsvfs), NULL,
                      &zp->z_atime, sizeof (zp->z_atime));
          }
  
          if (mask & AT_MTIME) {
                  ZFS_TIME_ENCODE(&vap->va_mtime, mtime);
                  SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs), NULL,
                      mtime, sizeof (mtime));
          }
  
          /* XXX - shouldn't this be done *before* the ATIME/MTIME checks? */
          if (mask & AT_SIZE && !(mask & AT_MTIME)) {
                  SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs),
                      NULL, mtime, sizeof (mtime));
                  SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL,
                      &ctime, sizeof (ctime));
                  zfs_tstamp_update_setup(zp, CONTENT_MODIFIED, mtime, ctime,
                      B_TRUE);
          } else if (mask != 0) {
                  SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL,
                      &ctime, sizeof (ctime));
                  zfs_tstamp_update_setup(zp, STATE_CHANGED, mtime, ctime,
                      B_TRUE);
                  if (attrzp) {
                          SA_ADD_BULK_ATTR(xattr_bulk, xattr_count,
                              SA_ZPL_CTIME(zfsvfs), NULL,
                              &ctime, sizeof (ctime));
                          zfs_tstamp_update_setup(attrzp, STATE_CHANGED,
                              mtime, ctime, B_TRUE);
                  }
          }
          /*
           * Do this after setting timestamps to prevent timestamp
           * update from toggling bit
           */
  
          if (xoap && (mask & AT_XVATTR)) {
  
                  if (XVA_ISSET_REQ(xvap, XAT_CREATETIME))
                          xoap->xoa_createtime = vap->va_birthtime;
                  /*
                   * restore trimmed off masks
                   * so that return masks can be set for caller.
                   */
  
                  if (XVA_ISSET_REQ(&tmpxvattr, XAT_APPENDONLY)) {
                          XVA_SET_REQ(xvap, XAT_APPENDONLY);
                  }
                  if (XVA_ISSET_REQ(&tmpxvattr, XAT_NOUNLINK)) {
                          XVA_SET_REQ(xvap, XAT_NOUNLINK);
                  }
                  if (XVA_ISSET_REQ(&tmpxvattr, XAT_IMMUTABLE)) {
                          XVA_SET_REQ(xvap, XAT_IMMUTABLE);
                  }
                  if (XVA_ISSET_REQ(&tmpxvattr, XAT_NODUMP)) {
                          XVA_SET_REQ(xvap, XAT_NODUMP);
                  }
                  if (XVA_ISSET_REQ(&tmpxvattr, XAT_AV_MODIFIED)) {
                          XVA_SET_REQ(xvap, XAT_AV_MODIFIED);
                  }
                  if (XVA_ISSET_REQ(&tmpxvattr, XAT_AV_QUARANTINED)) {
                          XVA_SET_REQ(xvap, XAT_AV_QUARANTINED);
                  }
  
                  if (XVA_ISSET_REQ(xvap, XAT_AV_SCANSTAMP))
                          ASSERT(vp->v_type == VREG);
  
                  zfs_xvattr_set(zp, xvap, tx);
          }
  
          if (fuid_dirtied)
                  zfs_fuid_sync(zfsvfs, tx);
  
          if (mask != 0)
                  zfs_log_setattr(zilog, tx, TX_SETATTR, zp, vap, mask, fuidp);
  
          if (mask & (AT_UID|AT_GID|AT_MODE))
                  mutex_exit(&zp->z_acl_lock);
  
          if (attrzp) {
                  if (mask & (AT_UID|AT_GID|AT_MODE))
                          mutex_exit(&attrzp->z_acl_lock);
          }
  out:
          if (err == 0 && attrzp) {
                  err2 = sa_bulk_update(attrzp->z_sa_hdl, xattr_bulk,
                      xattr_count, tx);
                  ASSERT(err2 == 0);
          }
  
          if (attrzp)
                  vput(ZTOV(attrzp));
  
          if (aclp)
                  zfs_acl_free(aclp);
  
          if (fuidp) {
                  zfs_fuid_info_free(fuidp);
                  fuidp = NULL;
          }
  
          if (err) {
                  dmu_tx_abort(tx);
          } else {
                  err2 = sa_bulk_update(zp->z_sa_hdl, bulk, count, tx);
                  dmu_tx_commit(tx);
          }
  
  out2:
          if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zilog, 0);
  
          ZFS_EXIT(zfsvfs);
          return (err);
  }
  
  /*
   * We acquire all but fdvp locks using non-blocking acquisitions.  If we
   * fail to acquire any lock in the path we will drop all held locks,
   * acquire the new lock in a blocking fashion, and then release it and
   * restart the rename.  This acquire/release step ensures that we do not
   * spin on a lock waiting for release.  On error release all vnode locks
   * and decrement references the way tmpfs_rename() would do.
   */
  static int
  zfs_rename_relock(struct vnode *sdvp, struct vnode **svpp,
      struct vnode *tdvp, struct vnode **tvpp,
      const struct componentname *scnp, const struct componentname *tcnp)
  {
          zfsvfs_t        *zfsvfs;
          struct vnode    *nvp, *svp, *tvp;
          znode_t         *sdzp, *tdzp, *szp, *tzp;
          const char      *snm = scnp->cn_nameptr;
          const char      *tnm = tcnp->cn_nameptr;
          int error;
  
          VOP_UNLOCK(tdvp, 0);
          if (*tvpp != NULL && *tvpp != tdvp)
                  VOP_UNLOCK(*tvpp, 0);
  
  relock:
          error = vn_lock(sdvp, LK_EXCLUSIVE);
          if (error)
                  goto out;
          sdzp = VTOZ(sdvp);
  
          error = vn_lock(tdvp, LK_EXCLUSIVE | LK_NOWAIT);
          if (error != 0) {
                  VOP_UNLOCK(sdvp, 0);
                  if (error != EBUSY)
                          goto out;
                  error = vn_lock(tdvp, LK_EXCLUSIVE);
                  if (error)
                          goto out;
                  VOP_UNLOCK(tdvp, 0);
                  goto relock;
          }
          tdzp = VTOZ(tdvp);
  
          /*
           * Before using sdzp and tdzp we must ensure that they are live.
           * As a porting legacy from illumos we have two things to worry
           * about.  One is typical for FreeBSD and it is that the vnode is
           * not reclaimed (doomed).  The other is that the znode is live.
           * The current code can invalidate the znode without acquiring the
           * corresponding vnode lock if the object represented by the znode
           * and vnode is no longer valid after a rollback or receive operation.
           * z_teardown_lock hidden behind ZFS_ENTER and ZFS_EXIT is the lock
           * that protects the znodes from the invalidation.
           */
          zfsvfs = sdzp->z_zfsvfs;
          ASSERT3P(zfsvfs, ==, tdzp->z_zfsvfs);
          ZFS_ENTER(zfsvfs);
  
          /*
           * We can not use ZFS_VERIFY_ZP() here because it could directly return
           * bypassing the cleanup code in the case of an error.
           */
          if (tdzp->z_sa_hdl == NULL || sdzp->z_sa_hdl == NULL) {
                  ZFS_EXIT(zfsvfs);
                  VOP_UNLOCK(sdvp, 0);
                  VOP_UNLOCK(tdvp, 0);
                  error = SET_ERROR(EIO);
                  goto out;
          }
  
          /*
           * Re-resolve svp to be certain it still exists and fetch the
           * correct vnode.
           */
          error = zfs_dirent_lookup(sdzp, snm, &szp, ZEXISTS);
          if (error != 0) {
                  /* Source entry invalid or not there. */
                  ZFS_EXIT(zfsvfs);
                  VOP_UNLOCK(sdvp, 0);
                  VOP_UNLOCK(tdvp, 0);
                  if ((scnp->cn_flags & ISDOTDOT) != 0 ||
                      (scnp->cn_namelen == 1 && scnp->cn_nameptr[0] == '.'))
                          error = SET_ERROR(EINVAL);
                  goto out;
          }
          svp = ZTOV(szp);
  
          /*
           * Re-resolve tvp, if it disappeared we just carry on.
           */
          error = zfs_dirent_lookup(tdzp, tnm, &tzp, 0);
          if (error != 0) {
                  ZFS_EXIT(zfsvfs);
                  VOP_UNLOCK(sdvp, 0);
                  VOP_UNLOCK(tdvp, 0);
                  vrele(svp);
                  if ((tcnp->cn_flags & ISDOTDOT) != 0)
                          error = SET_ERROR(EINVAL);
                  goto out;
          }
          if (tzp != NULL)
                  tvp = ZTOV(tzp);
          else
                  tvp = NULL;
  
          /*
           * At present the vnode locks must be acquired before z_teardown_lock,
           * although it would be more logical to use the opposite order.
           */
          ZFS_EXIT(zfsvfs);
  
          /*
           * Now try acquire locks on svp and tvp.
           */
          nvp = svp;
          error = vn_lock(nvp, LK_EXCLUSIVE | LK_NOWAIT);
          if (error != 0) {
                  VOP_UNLOCK(sdvp, 0);
                  VOP_UNLOCK(tdvp, 0);
                  if (tvp != NULL)
                          vrele(tvp);
                  if (error != EBUSY) {
                          vrele(nvp);
                          goto out;
                  }
                  error = vn_lock(nvp, LK_EXCLUSIVE);
                  if (error != 0) {
                          vrele(nvp);
                          goto out;
                  }
                  VOP_UNLOCK(nvp, 0);
                  /*
                   * Concurrent rename race.
                   * XXX ?
                   */
                  if (nvp == tdvp) {
                          vrele(nvp);
                          error = SET_ERROR(EINVAL);
                          goto out;
                  }
                  vrele(*svpp);
                  *svpp = nvp;
                  goto relock;
          }
          vrele(*svpp);
          *svpp = nvp;
  
          if (*tvpp != NULL)
                  vrele(*tvpp);
          *tvpp = NULL;
          if (tvp != NULL) {
                  nvp = tvp;
                  error = vn_lock(nvp, LK_EXCLUSIVE | LK_NOWAIT);
                  if (error != 0) {
                          VOP_UNLOCK(sdvp, 0);
                          VOP_UNLOCK(tdvp, 0);
                          VOP_UNLOCK(*svpp, 0);
                          if (error != EBUSY) {
                                  vrele(nvp);
                                  goto out;
                          }
                          error = vn_lock(nvp, LK_EXCLUSIVE);
                          if (error != 0) {
                                  vrele(nvp);
                                  goto out;
                          }
                          vput(nvp);
                          goto relock;
                  }
                  *tvpp = nvp;
          }
  
          return (0);
  
  out:
          return (error);
  }
  
  /*
   * Note that we must use VRELE_ASYNC in this function as it walks
   * up the directory tree and vrele may need to acquire an exclusive
   * lock if a last reference to a vnode is dropped.
   */
  static int
  zfs_rename_check(znode_t *szp, znode_t *sdzp, znode_t *tdzp)
  {
          zfsvfs_t        *zfsvfs;
          znode_t         *zp, *zp1;
          uint64_t        parent;
          int             error;
  
          zfsvfs = tdzp->z_zfsvfs;
          if (tdzp == szp)
                  return (SET_ERROR(EINVAL));
          if (tdzp == sdzp)
                  return (0);
          if (tdzp->z_id == zfsvfs->z_root)
                  return (0);
          zp = tdzp;
          for (;;) {
                  ASSERT(!zp->z_unlinked);
                  if ((error = sa_lookup(zp->z_sa_hdl,
                      SA_ZPL_PARENT(zfsvfs), &parent, sizeof (parent))) != 0)
                          break;
  
                  if (parent == szp->z_id) {
                          error = SET_ERROR(EINVAL);
                          break;
                  }
                  if (parent == zfsvfs->z_root)
                          break;
                  if (parent == sdzp->z_id)
                          break;
  
                  error = zfs_zget(zfsvfs, parent, &zp1);
                  if (error != 0)
                          break;
  
                  if (zp != tdzp)
                          VN_RELE_ASYNC(ZTOV(zp),
                              dsl_pool_vnrele_taskq(dmu_objset_pool(zfsvfs->z_os)));
                  zp = zp1;
          }
  
          if (error == ENOTDIR)
                  panic("checkpath: .. not a directory\n");
          if (zp != tdzp)
                  VN_RELE_ASYNC(ZTOV(zp),
                      dsl_pool_vnrele_taskq(dmu_objset_pool(zfsvfs->z_os)));
          return (error);
  }
  
  /*
   * Move an entry from the provided source directory to the target
   * directory.  Change the entry name as indicated.
   *
   *      IN:     sdvp    - Source directory containing the "old entry".
   *              snm     - Old entry name.
   *              tdvp    - Target directory to contain the "new entry".
   *              tnm     - New entry name.
   *              cr      - credentials of caller.
   *              ct      - caller context
   *              flags   - case flags
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      sdvp,tdvp - ctime|mtime updated
   */
  /*ARGSUSED*/
  static int
  zfs_rename(vnode_t *sdvp, vnode_t **svpp, struct componentname *scnp,
      vnode_t *tdvp, vnode_t **tvpp, struct componentname *tcnp,
      cred_t *cr)
  {
          zfsvfs_t        *zfsvfs;
          znode_t         *sdzp, *tdzp, *szp, *tzp;
          zilog_t         *zilog = NULL;
          dmu_tx_t        *tx;
          char            *snm = scnp->cn_nameptr;
          char            *tnm = tcnp->cn_nameptr;
          int             error = 0;
  
          /* Reject renames across filesystems. */
          if ((*svpp)->v_mount != tdvp->v_mount ||
              ((*tvpp) != NULL && (*svpp)->v_mount != (*tvpp)->v_mount)) {
                  error = SET_ERROR(EXDEV);
                  goto out;
          }
  
          if (zfsctl_is_node(tdvp)) {
                  error = SET_ERROR(EXDEV);
                  goto out;
          }
  
          /*
           * Lock all four vnodes to ensure safety and semantics of renaming.
           */
          error = zfs_rename_relock(sdvp, svpp, tdvp, tvpp, scnp, tcnp);
          if (error != 0) {
                  /* no vnodes are locked in the case of error here */
                  return (error);
          }
  
          tdzp = VTOZ(tdvp);
          sdzp = VTOZ(sdvp);
          zfsvfs = tdzp->z_zfsvfs;
          zilog = zfsvfs->z_log;
  
          /*
           * After we re-enter ZFS_ENTER() we will have to revalidate all
           * znodes involved.
           */
          ZFS_ENTER(zfsvfs);
  
          if (zfsvfs->z_utf8 && u8_validate(tnm,
              strlen(tnm), NULL, U8_VALIDATE_ENTIRE, &error) < 0) {
                  error = SET_ERROR(EILSEQ);
                  goto unlockout;
          }
  
          /* If source and target are the same file, there is nothing to do. */
          if ((*svpp) == (*tvpp)) {
                  error = 0;
                  goto unlockout;
          }
  
          if (((*svpp)->v_type == VDIR && (*svpp)->v_mountedhere != NULL) ||
              ((*tvpp) != NULL && (*tvpp)->v_type == VDIR &&
              (*tvpp)->v_mountedhere != NULL)) {
                  error = SET_ERROR(EXDEV);
                  goto unlockout;
          }
  
          /*
           * We can not use ZFS_VERIFY_ZP() here because it could directly return
           * bypassing the cleanup code in the case of an error.
           */
          if (tdzp->z_sa_hdl == NULL || sdzp->z_sa_hdl == NULL) {
                  error = SET_ERROR(EIO);
                  goto unlockout;
          }
  
          szp = VTOZ(*svpp);
          tzp = *tvpp == NULL ? NULL : VTOZ(*tvpp);
          if (szp->z_sa_hdl == NULL || (tzp != NULL && tzp->z_sa_hdl == NULL)) {
                  error = SET_ERROR(EIO);
                  goto unlockout;
          }
  
          /*
           * This is to prevent the creation of links into attribute space
           * by renaming a linked file into/outof an attribute directory.
           * See the comment in zfs_link() for why this is considered bad.
           */
          if ((tdzp->z_pflags & ZFS_XATTR) != (sdzp->z_pflags & ZFS_XATTR)) {
                  error = SET_ERROR(EINVAL);
                  goto unlockout;
          }
  
          /*
           * Must have write access at the source to remove the old entry
           * and write access at the target to create the new entry.
           * Note that if target and source are the same, this can be
           * done in a single check.
           */
          if (error = zfs_zaccess_rename(sdzp, szp, tdzp, tzp, cr))
                  goto unlockout;
  
          if ((*svpp)->v_type == VDIR) {
                  /*
                   * Avoid ".", "..", and aliases of "." for obvious reasons.
                   */
                  if ((scnp->cn_namelen == 1 && scnp->cn_nameptr[0] == '.') ||
                      sdzp == szp ||
                      (scnp->cn_flags | tcnp->cn_flags) & ISDOTDOT) {
                          error = EINVAL;
                          goto unlockout;
                  }
  
                  /*
                   * Check to make sure rename is valid.
                   * Can't do a move like this: /usr/a/b to /usr/a/b/c/d
                   */
                  if (error = zfs_rename_check(szp, sdzp, tdzp))
                          goto unlockout;
          }
  
          /*
           * Does target exist?
           */
          if (tzp) {
                  /*
                   * Source and target must be the same type.
                   */
                  if ((*svpp)->v_type == VDIR) {
                          if ((*tvpp)->v_type != VDIR) {
                                  error = SET_ERROR(ENOTDIR);
                                  goto unlockout;
                          } else {
                                  cache_purge(tdvp);
                                  if (sdvp != tdvp)
                                          cache_purge(sdvp);
                          }
                  } else {
                          if ((*tvpp)->v_type == VDIR) {
                                  error = SET_ERROR(EISDIR);
                                  goto unlockout;
                          }
                  }
          }
  
          vnevent_rename_src(*svpp, sdvp, scnp->cn_nameptr, ct);
          if (tzp)
                  vnevent_rename_dest(*tvpp, tdvp, tnm, ct);
  
          /*
           * notify the target directory if it is not the same
           * as source directory.
           */
          if (tdvp != sdvp) {
                  vnevent_rename_dest_dir(tdvp, ct);
          }
  
          tx = dmu_tx_create(zfsvfs->z_os);
          dmu_tx_hold_sa(tx, szp->z_sa_hdl, B_FALSE);
          dmu_tx_hold_sa(tx, sdzp->z_sa_hdl, B_FALSE);
          dmu_tx_hold_zap(tx, sdzp->z_id, FALSE, snm);
          dmu_tx_hold_zap(tx, tdzp->z_id, TRUE, tnm);
          if (sdzp != tdzp) {
                  dmu_tx_hold_sa(tx, tdzp->z_sa_hdl, B_FALSE);
                  zfs_sa_upgrade_txholds(tx, tdzp);
          }
          if (tzp) {
                  dmu_tx_hold_sa(tx, tzp->z_sa_hdl, B_FALSE);
                  zfs_sa_upgrade_txholds(tx, tzp);
          }
  
          zfs_sa_upgrade_txholds(tx, szp);
          dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL);
          error = dmu_tx_assign(tx, TXG_WAIT);
          if (error) {
                  dmu_tx_abort(tx);
                  goto unlockout;
          }
  
  
          if (tzp)        /* Attempt to remove the existing target */
                  error = zfs_link_destroy(tdzp, tnm, tzp, tx, 0, NULL);
  
          if (error == 0) {
                  error = zfs_link_create(tdzp, tnm, szp, tx, ZRENAMING);
                  if (error == 0) {
                          szp->z_pflags |= ZFS_AV_MODIFIED;
  
                          error = sa_update(szp->z_sa_hdl, SA_ZPL_FLAGS(zfsvfs),
                              (void *)&szp->z_pflags, sizeof (uint64_t), tx);
                          ASSERT0(error);
  
                          error = zfs_link_destroy(sdzp, snm, szp, tx, ZRENAMING,
                              NULL);
                          if (error == 0) {
                                  zfs_log_rename(zilog, tx, TX_RENAME, sdzp,
                                      snm, tdzp, tnm, szp);
  
                                  /*
                                   * Update path information for the target vnode
                                   */
                                  vn_renamepath(tdvp, *svpp, tnm, strlen(tnm));
                          } else {
                                  /*
                                   * At this point, we have successfully created
                                   * the target name, but have failed to remove
                                   * the source name.  Since the create was done
                                   * with the ZRENAMING flag, there are
                                   * complications; for one, the link count is
                                   * wrong.  The easiest way to deal with this
                                   * is to remove the newly created target, and
                                   * return the original error.  This must
                                   * succeed; fortunately, it is very unlikely to
                                   * fail, since we just created it.
                                   */
                                  VERIFY3U(zfs_link_destroy(tdzp, tnm, szp, tx,
                                      ZRENAMING, NULL), ==, 0);
                          }
                  }
                  if (error == 0) {
                          cache_purge(*svpp);
                          if (*tvpp != NULL)
                                  cache_purge(*tvpp);
                          cache_purge_negative(tdvp);
                  }
          }
  
          dmu_tx_commit(tx);
  
  unlockout:                      /* all 4 vnodes are locked, ZFS_ENTER called */
          ZFS_EXIT(zfsvfs);
          VOP_UNLOCK(*svpp, 0);
          VOP_UNLOCK(sdvp, 0);
  
  out:                            /* original two vnodes are locked */
          if (error == 0 && zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zilog, 0);
  
          if (*tvpp != NULL)
                  VOP_UNLOCK(*tvpp, 0);
          if (tdvp != *tvpp)
                  VOP_UNLOCK(tdvp, 0);
          return (error);
  }
  
  /*
   * Insert the indicated symbolic reference entry into the directory.
   *
   *      IN:     dvp     - Directory to contain new symbolic link.
   *              link    - Name for new symlink entry.
   *              vap     - Attributes of new entry.
   *              cr      - credentials of caller.
   *              ct      - caller context
   *              flags   - case flags
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      dvp - ctime|mtime updated
   */
  /*ARGSUSED*/
  static int
  zfs_symlink(vnode_t *dvp, vnode_t **vpp, char *name, vattr_t *vap, char *link,
      cred_t *cr, kthread_t *td)
  {
          znode_t         *zp, *dzp = VTOZ(dvp);
          dmu_tx_t        *tx;
          zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
          zilog_t         *zilog;
          uint64_t        len = strlen(link);
          int             error;
          zfs_acl_ids_t   acl_ids;
          boolean_t       fuid_dirtied;
          uint64_t        txtype = TX_SYMLINK;
          int             flags = 0;
  
          ASSERT(vap->va_type == VLNK);
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(dzp);
          zilog = zfsvfs->z_log;
  
          if (zfsvfs->z_utf8 && u8_validate(name, strlen(name),
              NULL, U8_VALIDATE_ENTIRE, &error) < 0) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EILSEQ));
          }
  
          if (len > MAXPATHLEN) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(ENAMETOOLONG));
          }
  
          if ((error = zfs_acl_ids_create(dzp, 0,
              vap, cr, NULL, &acl_ids)) != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          /*
           * Attempt to lock directory; fail if entry already exists.
           */
          error = zfs_dirent_lookup(dzp, name, &zp, ZNEW);
          if (error) {
                  zfs_acl_ids_free(&acl_ids);
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          if (error = zfs_zaccess(dzp, ACE_ADD_FILE, 0, B_FALSE, cr)) {
                  zfs_acl_ids_free(&acl_ids);
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          if (zfs_acl_ids_overquota(zfsvfs, &acl_ids)) {
                  zfs_acl_ids_free(&acl_ids);
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EDQUOT));
          }
  
          getnewvnode_reserve(1);
          tx = dmu_tx_create(zfsvfs->z_os);
          fuid_dirtied = zfsvfs->z_fuid_dirty;
          dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0, MAX(1, len));
          dmu_tx_hold_zap(tx, dzp->z_id, TRUE, name);
          dmu_tx_hold_sa_create(tx, acl_ids.z_aclp->z_acl_bytes +
              ZFS_SA_BASE_ATTR_SIZE + len);
          dmu_tx_hold_sa(tx, dzp->z_sa_hdl, B_FALSE);
          if (!zfsvfs->z_use_sa && acl_ids.z_aclp->z_acl_bytes > ZFS_ACE_SPACE) {
                  dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
                      acl_ids.z_aclp->z_acl_bytes);
          }
          if (fuid_dirtied)
                  zfs_fuid_txhold(zfsvfs, tx);
          error = dmu_tx_assign(tx, TXG_WAIT);
          if (error) {
                  zfs_acl_ids_free(&acl_ids);
                  dmu_tx_abort(tx);
                  getnewvnode_drop_reserve();
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          /*
           * Create a new object for the symlink.
           * for version 4 ZPL datsets the symlink will be an SA attribute
           */
          zfs_mknode(dzp, vap, tx, cr, 0, &zp, &acl_ids);
  
          if (fuid_dirtied)
                  zfs_fuid_sync(zfsvfs, tx);
  
          if (zp->z_is_sa)
                  error = sa_update(zp->z_sa_hdl, SA_ZPL_SYMLINK(zfsvfs),
                      link, len, tx);
          else
                  zfs_sa_symlink(zp, link, len, tx);
  
          zp->z_size = len;
          (void) sa_update(zp->z_sa_hdl, SA_ZPL_SIZE(zfsvfs),
              &zp->z_size, sizeof (zp->z_size), tx);
          /*
           * Insert the new object into the directory.
           */
          (void) zfs_link_create(dzp, name, zp, tx, ZNEW);
  
          zfs_log_symlink(zilog, tx, txtype, dzp, zp, name, link);
          *vpp = ZTOV(zp);
  
          zfs_acl_ids_free(&acl_ids);
  
          dmu_tx_commit(tx);
  
          getnewvnode_drop_reserve();
  
          if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zilog, 0);
  
          ZFS_EXIT(zfsvfs);
          return (error);
  }
  
  /*
   * Return, in the buffer contained in the provided uio structure,
   * the symbolic path referred to by vp.
   *
   *      IN:     vp      - vnode of symbolic link.
   *              uio     - structure to contain the link path.
   *              cr      - credentials of caller.
   *              ct      - caller context
   *
   *      OUT:    uio     - structure containing the link path.
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      vp - atime updated
   */
  /* ARGSUSED */
  static int
  zfs_readlink(vnode_t *vp, uio_t *uio, cred_t *cr, caller_context_t *ct)
  {
          znode_t         *zp = VTOZ(vp);
          zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
          int             error;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
  
          if (zp->z_is_sa)
                  error = sa_lookup_uio(zp->z_sa_hdl,
                      SA_ZPL_SYMLINK(zfsvfs), uio);
          else
                  error = zfs_sa_readlink(zp, uio);
  
          ZFS_ACCESSTIME_STAMP(zfsvfs, zp);
  
          ZFS_EXIT(zfsvfs);
          return (error);
  }
  
  /*
   * Insert a new entry into directory tdvp referencing svp.
   *
   *      IN:     tdvp    - Directory to contain new entry.
   *              svp     - vnode of new entry.
   *              name    - name of new entry.
   *              cr      - credentials of caller.
   *              ct      - caller context
   *
   *      RETURN: 0 on success, error code on failure.
   *
   * Timestamps:
   *      tdvp - ctime|mtime updated
   *       svp - ctime updated
   */
  /* ARGSUSED */
  static int
  zfs_link(vnode_t *tdvp, vnode_t *svp, char *name, cred_t *cr,
      caller_context_t *ct, int flags)
  {
          znode_t         *dzp = VTOZ(tdvp);
          znode_t         *tzp, *szp;
          zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
          zilog_t         *zilog;
          dmu_tx_t        *tx;
          int             error;
          uint64_t        parent;
          uid_t           owner;
  
          ASSERT(tdvp->v_type == VDIR);
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(dzp);
          zilog = zfsvfs->z_log;
  
          /*
           * POSIX dictates that we return EPERM here.
           * Better choices include ENOTSUP or EISDIR.
           */
          if (svp->v_type == VDIR) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EPERM));
          }
  
          szp = VTOZ(svp);
          ZFS_VERIFY_ZP(szp);
  
          if (szp->z_pflags & (ZFS_APPENDONLY | ZFS_IMMUTABLE | ZFS_READONLY)) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EPERM));
          }
  
          /* Prevent links to .zfs/shares files */
  
          if ((error = sa_lookup(szp->z_sa_hdl, SA_ZPL_PARENT(zfsvfs),
              &parent, sizeof (uint64_t))) != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
          if (parent == zfsvfs->z_shares_dir) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EPERM));
          }
  
          if (zfsvfs->z_utf8 && u8_validate(name,
              strlen(name), NULL, U8_VALIDATE_ENTIRE, &error) < 0) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EILSEQ));
          }
  
          /*
           * We do not support links between attributes and non-attributes
           * because of the potential security risk of creating links
           * into "normal" file space in order to circumvent restrictions
           * imposed in attribute space.
           */
          if ((szp->z_pflags & ZFS_XATTR) != (dzp->z_pflags & ZFS_XATTR)) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EINVAL));
          }
  
  
          owner = zfs_fuid_map_id(zfsvfs, szp->z_uid, cr, ZFS_OWNER);
          if (owner != crgetuid(cr) && secpolicy_basic_link(svp, cr) != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(EPERM));
          }
  
          if (error = zfs_zaccess(dzp, ACE_ADD_FILE, 0, B_FALSE, cr)) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          /*
           * Attempt to lock directory; fail if entry already exists.
           */
          error = zfs_dirent_lookup(dzp, name, &tzp, ZNEW);
          if (error) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          tx = dmu_tx_create(zfsvfs->z_os);
          dmu_tx_hold_sa(tx, szp->z_sa_hdl, B_FALSE);
          dmu_tx_hold_zap(tx, dzp->z_id, TRUE, name);
          zfs_sa_upgrade_txholds(tx, szp);
          zfs_sa_upgrade_txholds(tx, dzp);
          error = dmu_tx_assign(tx, TXG_WAIT);
          if (error) {
                  dmu_tx_abort(tx);
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          error = zfs_link_create(dzp, name, szp, tx, 0);
  
          if (error == 0) {
                  uint64_t txtype = TX_LINK;
                  zfs_log_link(zilog, tx, txtype, dzp, szp, name);
          }
  
          dmu_tx_commit(tx);
  
          if (error == 0) {
                  vnevent_link(svp, ct);
          }
  
          if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zilog, 0);
  
          ZFS_EXIT(zfsvfs);
          return (error);
  }
  
  
  /*ARGSUSED*/
  void
  zfs_inactive(vnode_t *vp, cred_t *cr, caller_context_t *ct)
  {
          znode_t *zp = VTOZ(vp);
          zfsvfs_t *zfsvfs = zp->z_zfsvfs;
          int error;
  
          rw_enter(&zfsvfs->z_teardown_inactive_lock, RW_READER);
          if (zp->z_sa_hdl == NULL) {
                  /*
                   * The fs has been unmounted, or we did a
                   * suspend/resume and this file no longer exists.
                   */
                  rw_exit(&zfsvfs->z_teardown_inactive_lock);
                  vrecycle(vp);
                  return;
          }
  
          if (zp->z_unlinked) {
                  /*
                   * Fast path to recycle a vnode of a removed file.
                   */
                  rw_exit(&zfsvfs->z_teardown_inactive_lock);
                  vrecycle(vp);
                  return;
          }
  
          if (zp->z_atime_dirty && zp->z_unlinked == 0) {
                  dmu_tx_t *tx = dmu_tx_create(zfsvfs->z_os);
  
                  dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE);
                  zfs_sa_upgrade_txholds(tx, zp);
                  error = dmu_tx_assign(tx, TXG_WAIT);
                  if (error) {
                          dmu_tx_abort(tx);
                  } else {
                          (void) sa_update(zp->z_sa_hdl, SA_ZPL_ATIME(zfsvfs),
                              (void *)&zp->z_atime, sizeof (zp->z_atime), tx);
                          zp->z_atime_dirty = 0;
                          dmu_tx_commit(tx);
                  }
          }
          rw_exit(&zfsvfs->z_teardown_inactive_lock);
  }
  
  
  CTASSERT(sizeof(struct zfid_short) <= sizeof(struct fid));
  CTASSERT(sizeof(struct zfid_long) <= sizeof(struct fid));
  
  /*ARGSUSED*/
  static int
  zfs_fid(vnode_t *vp, fid_t *fidp, caller_context_t *ct)
  {
          znode_t         *zp = VTOZ(vp);
          zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
          uint32_t        gen;
          uint64_t        gen64;
          uint64_t        object = zp->z_id;
          zfid_short_t    *zfid;
          int             size, i, error;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
  
          if ((error = sa_lookup(zp->z_sa_hdl, SA_ZPL_GEN(zfsvfs),
              &gen64, sizeof (uint64_t))) != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          gen = (uint32_t)gen64;
  
          size = (zfsvfs->z_parent != zfsvfs) ? LONG_FID_LEN : SHORT_FID_LEN;
  
  #ifdef illumos
          if (fidp->fid_len < size) {
                  fidp->fid_len = size;
                  ZFS_EXIT(zfsvfs);
                  return (SET_ERROR(ENOSPC));
          }
  #else
          fidp->fid_len = size;
  #endif
  
          zfid = (zfid_short_t *)fidp;
  
          zfid->zf_len = size;
  
          for (i = 0; i < sizeof (zfid->zf_object); i++)
                  zfid->zf_object[i] = (uint8_t)(object >> (8 * i));
  
          /* Must have a non-zero generation number to distinguish from .zfs */
          if (gen == 0)
                  gen = 1;
          for (i = 0; i < sizeof (zfid->zf_gen); i++)
                  zfid->zf_gen[i] = (uint8_t)(gen >> (8 * i));
  
          if (size == LONG_FID_LEN) {
                  uint64_t        objsetid = dmu_objset_id(zfsvfs->z_os);
                  zfid_long_t     *zlfid;
  
                  zlfid = (zfid_long_t *)fidp;
  
                  for (i = 0; i < sizeof (zlfid->zf_setid); i++)
                          zlfid->zf_setid[i] = (uint8_t)(objsetid >> (8 * i));
  
                  /* XXX - this should be the generation number for the objset */
                  for (i = 0; i < sizeof (zlfid->zf_setgen); i++)
                          zlfid->zf_setgen[i] = 0;
          }
  
          ZFS_EXIT(zfsvfs);
          return (0);
  }
  
  static int
  zfs_pathconf(vnode_t *vp, int cmd, ulong_t *valp, cred_t *cr,
      caller_context_t *ct)
  {
          znode_t         *zp, *xzp;
          zfsvfs_t        *zfsvfs;
          int             error;
  
          switch (cmd) {
          case _PC_LINK_MAX:
                  *valp = MIN(LONG_MAX, ZFS_LINK_MAX);
                  return (0);
  
          case _PC_FILESIZEBITS:
                  *valp = 64;
                  return (0);
  #ifdef illumos
          case _PC_XATTR_EXISTS:
                  zp = VTOZ(vp);
                  zfsvfs = zp->z_zfsvfs;
                  ZFS_ENTER(zfsvfs);
                  ZFS_VERIFY_ZP(zp);
                  *valp = 0;
                  error = zfs_dirent_lookup(zp, "", &xzp,
                      ZXATTR | ZEXISTS | ZSHARED);
                  if (error == 0) {
                          if (!zfs_dirempty(xzp))
                                  *valp = 1;
                          vrele(ZTOV(xzp));
                  } else if (error == ENOENT) {
                          /*
                           * If there aren't extended attributes, it's the
                           * same as having zero of them.
                           */
                          error = 0;
                  }
                  ZFS_EXIT(zfsvfs);
                  return (error);
  
          case _PC_SATTR_ENABLED:
          case _PC_SATTR_EXISTS:
                  *valp = vfs_has_feature(vp->v_vfsp, VFSFT_SYSATTR_VIEWS) &&
                      (vp->v_type == VREG || vp->v_type == VDIR);
                  return (0);
  
          case _PC_ACCESS_FILTERING:
                  *valp = vfs_has_feature(vp->v_vfsp, VFSFT_ACCESS_FILTER) &&
                      vp->v_type == VDIR;
                  return (0);
  
          case _PC_ACL_ENABLED:
                  *valp = _ACL_ACE_ENABLED;
                  return (0);
  #endif  /* illumos */
          case _PC_MIN_HOLE_SIZE:
                  *valp = (int)SPA_MINBLOCKSIZE;
                  return (0);
  #ifdef illumos
          case _PC_TIMESTAMP_RESOLUTION:
                  /* nanosecond timestamp resolution */
                  *valp = 1L;
                  return (0);
  #endif
          case _PC_ACL_EXTENDED:
                  *valp = 0;
                  return (0);
  
          case _PC_ACL_NFS4:
                  *valp = 1;
                  return (0);
  
          case _PC_ACL_PATH_MAX:
                  *valp = ACL_MAX_ENTRIES;
                  return (0);
  
          default:
                  return (EOPNOTSUPP);
          }
  }
  
  /*ARGSUSED*/
  static int
  zfs_getsecattr(vnode_t *vp, vsecattr_t *vsecp, int flag, cred_t *cr,
      caller_context_t *ct)
  {
          znode_t *zp = VTOZ(vp);
          zfsvfs_t *zfsvfs = zp->z_zfsvfs;
          int error;
          boolean_t skipaclchk = (flag & ATTR_NOACLCHECK) ? B_TRUE : B_FALSE;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
          error = zfs_getacl(zp, vsecp, skipaclchk, cr);
          ZFS_EXIT(zfsvfs);
  
          return (error);
  }
  
  /*ARGSUSED*/
  int
  zfs_setsecattr(vnode_t *vp, vsecattr_t *vsecp, int flag, cred_t *cr,
      caller_context_t *ct)
  {
          znode_t *zp = VTOZ(vp);
          zfsvfs_t *zfsvfs = zp->z_zfsvfs;
          int error;
          boolean_t skipaclchk = (flag & ATTR_NOACLCHECK) ? B_TRUE : B_FALSE;
          zilog_t *zilog = zfsvfs->z_log;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
  
          error = zfs_setacl(zp, vsecp, skipaclchk, cr);
  
          if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zilog, 0);
  
          ZFS_EXIT(zfsvfs);
          return (error);
  }
  
  static int
  zfs_getpages(struct vnode *vp, vm_page_t *ma, int count, int *rbehind,
      int *rahead)
  {
          znode_t *zp = VTOZ(vp);
          zfsvfs_t *zfsvfs = zp->z_zfsvfs;
          objset_t *os = zp->z_zfsvfs->z_os;
          rl_t *rl;
          vm_object_t object;
          off_t start, end, obj_size;
          uint_t blksz;
          int pgsin_b, pgsin_a;
          int error;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
  
          start = IDX_TO_OFF(ma[0]->pindex);
          end = IDX_TO_OFF(ma[count - 1]->pindex + 1);
  
          /*
           * Lock a range covering all required and optional pages.
           * Note that we need to handle the case of the block size growing.
           */
          for (;;) {
                  blksz = zp->z_blksz;
                  rl = zfs_range_lock(zp, rounddown(start, blksz),
                      roundup(end, blksz) - rounddown(start, blksz), RL_READER);
                  if (blksz == zp->z_blksz)
                          break;
                  zfs_range_unlock(rl);
          }
  
          object = ma[0]->object;
          zfs_vmobject_wlock(object);
          obj_size = object->un_pager.vnp.vnp_size;
          zfs_vmobject_wunlock(object);
          if (IDX_TO_OFF(ma[count - 1]->pindex) >= obj_size) {
                  zfs_range_unlock(rl);
                  ZFS_EXIT(zfsvfs);
                  return (zfs_vm_pagerret_bad);
          }
  
          pgsin_b = 0;
          if (rbehind != NULL) {
                  pgsin_b = OFF_TO_IDX(start - rounddown(start, blksz));
                  pgsin_b = MIN(*rbehind, pgsin_b);
          }
  
          pgsin_a = 0;
          if (rahead != NULL) {
                  pgsin_a = OFF_TO_IDX(roundup(end, blksz) - end);
                  if (end + IDX_TO_OFF(pgsin_a) >= obj_size)
                          pgsin_a = OFF_TO_IDX(round_page(obj_size) - end);
                  pgsin_a = MIN(*rahead, pgsin_a);
          }
  
          /*
           * NB: we need to pass the exact byte size of the data that we expect
           * to read after accounting for the file size.  This is required because
           * ZFS will panic if we request DMU to read beyond the end of the last
           * allocated block.
           */
          error = dmu_read_pages(os, zp->z_id, ma, count, &pgsin_b, &pgsin_a,
              MIN(end, obj_size) - (end - PAGE_SIZE));
  
          zfs_range_unlock(rl);
          ZFS_ACCESSTIME_STAMP(zfsvfs, zp);
          ZFS_EXIT(zfsvfs);
  
          if (error != 0)
                  return (zfs_vm_pagerret_error);
  
          VM_CNT_INC(v_vnodein);
          VM_CNT_ADD(v_vnodepgsin, count + pgsin_b + pgsin_a);
          if (rbehind != NULL)
                  *rbehind = pgsin_b;
          if (rahead != NULL)
                  *rahead = pgsin_a;
          return (zfs_vm_pagerret_ok);
  }
  
  static int
  zfs_freebsd_getpages(ap)
          struct vop_getpages_args /* {
                  struct vnode *a_vp;
                  vm_page_t *a_m;
                  int a_count;
                  int *a_rbehind;
                  int *a_rahead;
          } */ *ap;
  {
  
          return (zfs_getpages(ap->a_vp, ap->a_m, ap->a_count, ap->a_rbehind,
              ap->a_rahead));
  }
  
  static int
  zfs_putpages(struct vnode *vp, vm_page_t *ma, size_t len, int flags,
      int *rtvals)
  {
          znode_t         *zp = VTOZ(vp);
          zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
          rl_t            *rl;
          dmu_tx_t        *tx;
          struct sf_buf   *sf;
          vm_object_t     object;
          vm_page_t       m;
          caddr_t         va;
          size_t          tocopy;
          size_t          lo_len;
          vm_ooffset_t    lo_off;
          vm_ooffset_t    off;
          uint_t          blksz;
          int             ncount;
          int             pcount;
          int             err;
          int             i;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
  
          object = vp->v_object;
          pcount = btoc(len);
          ncount = pcount;
  
          KASSERT(ma[0]->object == object, ("mismatching object"));
          KASSERT(len > 0 && (len & PAGE_MASK) == 0, ("unexpected length"));
  
          for (i = 0; i < pcount; i++)
                  rtvals[i] = zfs_vm_pagerret_error;
  
          off = IDX_TO_OFF(ma[0]->pindex);
          blksz = zp->z_blksz;
          lo_off = rounddown(off, blksz);
          lo_len = roundup(len + (off - lo_off), blksz);
          rl = zfs_range_lock(zp, lo_off, lo_len, RL_WRITER);
  
          zfs_vmobject_wlock(object);
          if (len + off > object->un_pager.vnp.vnp_size) {
                  if (object->un_pager.vnp.vnp_size > off) {
                          int pgoff;
  
                          len = object->un_pager.vnp.vnp_size - off;
                          ncount = btoc(len);
                          if ((pgoff = (int)len & PAGE_MASK) != 0) {
                                  /*
                                   * If the object is locked and the following
                                   * conditions hold, then the page's dirty
                                   * field cannot be concurrently changed by a
                                   * pmap operation.
                                   */
                                  m = ma[ncount - 1];
                                  vm_page_assert_sbusied(m);
                                  KASSERT(!pmap_page_is_write_mapped(m),
                                      ("zfs_putpages: page %p is not read-only", m));
                                  vm_page_clear_dirty(m, pgoff, PAGE_SIZE -
                                      pgoff);
                          }
                  } else {
                          len = 0;
                          ncount = 0;
                  }
                  if (ncount < pcount) {
                          for (i = ncount; i < pcount; i++) {
                                  rtvals[i] = zfs_vm_pagerret_bad;
                          }
                  }
          }
          zfs_vmobject_wunlock(object);
  
          if (ncount == 0)
                  goto out;
  
          if (zfs_owner_overquota(zfsvfs, zp, B_FALSE) ||
              zfs_owner_overquota(zfsvfs, zp, B_TRUE)) {
                  goto out;
          }
  
          tx = dmu_tx_create(zfsvfs->z_os);
          dmu_tx_hold_write(tx, zp->z_id, off, len);
  
          dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE);
          zfs_sa_upgrade_txholds(tx, zp);
          err = dmu_tx_assign(tx, TXG_WAIT);
          if (err != 0) {
                  dmu_tx_abort(tx);
                  goto out;
          }
  
          if (zp->z_blksz < PAGE_SIZE) {
                  for (i = 0; len > 0; off += tocopy, len -= tocopy, i++) {
                          tocopy = len > PAGE_SIZE ? PAGE_SIZE : len;
                          va = zfs_map_page(ma[i], &sf);
                          dmu_write(zfsvfs->z_os, zp->z_id, off, tocopy, va, tx);
                          zfs_unmap_page(sf);
                  }
          } else {
                  err = dmu_write_pages(zfsvfs->z_os, zp->z_id, off, len, ma, tx);
          }
  
          if (err == 0) {
                  uint64_t mtime[2], ctime[2];
                  sa_bulk_attr_t bulk[3];
                  int count = 0;
  
                  SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs), NULL,
                      &mtime, 16);
                  SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL,
                      &ctime, 16);
                  SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
                      &zp->z_pflags, 8);
                  zfs_tstamp_update_setup(zp, CONTENT_MODIFIED, mtime, ctime,
                      B_TRUE);
                  err = sa_bulk_update(zp->z_sa_hdl, bulk, count, tx);
                  ASSERT0(err);
                  zfs_log_write(zfsvfs->z_log, tx, TX_WRITE, zp, off, len, 0);
  
                  zfs_vmobject_wlock(object);
                  for (i = 0; i < ncount; i++) {
                          rtvals[i] = zfs_vm_pagerret_ok;
                          vm_page_undirty(ma[i]);
                  }
                  zfs_vmobject_wunlock(object);
                  VM_CNT_INC(v_vnodeout);
                  VM_CNT_ADD(v_vnodepgsout, ncount);
          }
          dmu_tx_commit(tx);
  
  out:
          zfs_range_unlock(rl);
          if ((flags & (zfs_vm_pagerput_sync | zfs_vm_pagerput_inval)) != 0 ||
              zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
                  zil_commit(zfsvfs->z_log, zp->z_id);
          ZFS_EXIT(zfsvfs);
          return (rtvals[0]);
  }
  
  int
  zfs_freebsd_putpages(ap)
          struct vop_putpages_args /* {
                  struct vnode *a_vp;
                  vm_page_t *a_m;
                  int a_count;
                  int a_sync;
                  int *a_rtvals;
          } */ *ap;
  {
  
          return (zfs_putpages(ap->a_vp, ap->a_m, ap->a_count, ap->a_sync,
              ap->a_rtvals));
  }
  
  static int
  zfs_freebsd_bmap(ap)
          struct vop_bmap_args /* {
                  struct vnode *a_vp;
                  daddr_t  a_bn;
                  struct bufobj **a_bop;
                  daddr_t *a_bnp;
                  int *a_runp;
                  int *a_runb;
          } */ *ap;
  {
  
          if (ap->a_bop != NULL)
                  *ap->a_bop = &ap->a_vp->v_bufobj;
          if (ap->a_bnp != NULL)
                  *ap->a_bnp = ap->a_bn;
          if (ap->a_runp != NULL)
                  *ap->a_runp = 0;
          if (ap->a_runb != NULL)
                  *ap->a_runb = 0;
  
          return (0);
  }
  
  static int
  zfs_freebsd_open(ap)
          struct vop_open_args /* {
                  struct vnode *a_vp;
                  int a_mode;
                  struct ucred *a_cred;
                  struct thread *a_td;
          } */ *ap;
  {
          vnode_t *vp = ap->a_vp;
          znode_t *zp = VTOZ(vp);
          int error;
  
          error = zfs_open(&vp, ap->a_mode, ap->a_cred, NULL);
          if (error == 0)
                  vnode_create_vobject(vp, zp->z_size, ap->a_td);
          return (error);
  }
  
  static int
  zfs_freebsd_close(ap)
          struct vop_close_args /* {
                  struct vnode *a_vp;
                  int  a_fflag;
                  struct ucred *a_cred;
                  struct thread *a_td;
          } */ *ap;
  {
  
          return (zfs_close(ap->a_vp, ap->a_fflag, 1, 0, ap->a_cred, NULL));
  }
  
  static int
  zfs_freebsd_ioctl(ap)
          struct vop_ioctl_args /* {
                  struct vnode *a_vp;
                  u_long a_command;
                  caddr_t a_data;
                  int a_fflag;
                  struct ucred *cred;
                  struct thread *td;
          } */ *ap;
  {
  
          return (zfs_ioctl(ap->a_vp, ap->a_command, (intptr_t)ap->a_data,
              ap->a_fflag, ap->a_cred, NULL, NULL));
  }
  
  static int
  ioflags(int ioflags)
  {
          int flags = 0;
  
          if (ioflags & IO_APPEND)
                  flags |= FAPPEND;
          if (ioflags & IO_NDELAY)
                  flags |= FNONBLOCK;
          if (ioflags & IO_SYNC)
                  flags |= (FSYNC | FDSYNC | FRSYNC);
  
          return (flags);
  }
  
  static int
  zfs_freebsd_read(ap)
          struct vop_read_args /* {
                  struct vnode *a_vp;
                  struct uio *a_uio;
                  int a_ioflag;
                  struct ucred *a_cred;
          } */ *ap;
  {
  
          return (zfs_read(ap->a_vp, ap->a_uio, ioflags(ap->a_ioflag),
              ap->a_cred, NULL));
  }
  
  static int
  zfs_freebsd_write(ap)
          struct vop_write_args /* {
                  struct vnode *a_vp;
                  struct uio *a_uio;
                  int a_ioflag;
                  struct ucred *a_cred;
          } */ *ap;
  {
  
          return (zfs_write(ap->a_vp, ap->a_uio, ioflags(ap->a_ioflag),
              ap->a_cred, NULL));
  }
  
  static int
  zfs_freebsd_access(ap)
          struct vop_access_args /* {
                  struct vnode *a_vp;
                  accmode_t a_accmode;
                  struct ucred *a_cred;
                  struct thread *a_td;
          } */ *ap;
  {
          vnode_t *vp = ap->a_vp;
          znode_t *zp = VTOZ(vp);
          accmode_t accmode;
          int error = 0;
  
          /*
           * ZFS itself only knowns about VREAD, VWRITE, VEXEC and VAPPEND,
           */
          accmode = ap->a_accmode & (VREAD|VWRITE|VEXEC|VAPPEND);
          if (accmode != 0)
                  error = zfs_access(ap->a_vp, accmode, 0, ap->a_cred, NULL);
  
          /*
           * VADMIN has to be handled by vaccess().
           */
          if (error == 0) {
                  accmode = ap->a_accmode & ~(VREAD|VWRITE|VEXEC|VAPPEND);
                  if (accmode != 0) {
                          error = vaccess(vp->v_type, zp->z_mode, zp->z_uid,
                              zp->z_gid, accmode, ap->a_cred, NULL);
                  }
          }
  
          /*
           * For VEXEC, ensure that at least one execute bit is set for
           * non-directories.
           */
          if (error == 0 && (ap->a_accmode & VEXEC) != 0 && vp->v_type != VDIR &&
              (zp->z_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) {
                  error = EACCES;
          }
  
          return (error);
  }
  
  static int
  zfs_freebsd_lookup(ap)
          struct vop_lookup_args /* {
                  struct vnode *a_dvp;
                  struct vnode **a_vpp;
                  struct componentname *a_cnp;
          } */ *ap;
  {
          struct componentname *cnp = ap->a_cnp;
          char nm[NAME_MAX + 1];
  
          ASSERT(cnp->cn_namelen < sizeof(nm));
          strlcpy(nm, cnp->cn_nameptr, MIN(cnp->cn_namelen + 1, sizeof(nm)));
  
          return (zfs_lookup(ap->a_dvp, nm, ap->a_vpp, cnp, cnp->cn_nameiop,
              cnp->cn_cred, cnp->cn_thread, 0));
  }
  
  static int
  zfs_cache_lookup(ap)
          struct vop_lookup_args /* {
                  struct vnode *a_dvp;
                  struct vnode **a_vpp;
                  struct componentname *a_cnp;
          } */ *ap;
  {
          zfsvfs_t *zfsvfs;
  
          zfsvfs = ap->a_dvp->v_mount->mnt_data;
          if (zfsvfs->z_use_namecache)
                  return (vfs_cache_lookup(ap));
          else
                  return (zfs_freebsd_lookup(ap));
  }
  
  static int
  zfs_freebsd_create(ap)
          struct vop_create_args /* {
                  struct vnode *a_dvp;
                  struct vnode **a_vpp;
                  struct componentname *a_cnp;
                  struct vattr *a_vap;
          } */ *ap;
  {
          zfsvfs_t *zfsvfs;
          struct componentname *cnp = ap->a_cnp;
          vattr_t *vap = ap->a_vap;
          int error, mode;
  
          ASSERT(cnp->cn_flags & SAVENAME);
  
          vattr_init_mask(vap);
          mode = vap->va_mode & ALLPERMS;
          zfsvfs = ap->a_dvp->v_mount->mnt_data;
  
          error = zfs_create(ap->a_dvp, cnp->cn_nameptr, vap, !EXCL, mode,
              ap->a_vpp, cnp->cn_cred, cnp->cn_thread);
          if (zfsvfs->z_use_namecache &&
              error == 0 && (cnp->cn_flags & MAKEENTRY) != 0)
                  cache_enter(ap->a_dvp, *ap->a_vpp, cnp);
          return (error);
  }
  
  static int
  zfs_freebsd_remove(ap)
          struct vop_remove_args /* {
                  struct vnode *a_dvp;
                  struct vnode *a_vp;
                  struct componentname *a_cnp;
          } */ *ap;
  {
  
          ASSERT(ap->a_cnp->cn_flags & SAVENAME);
  
          return (zfs_remove(ap->a_dvp, ap->a_vp, ap->a_cnp->cn_nameptr,
              ap->a_cnp->cn_cred));
  }
  
  static int
  zfs_freebsd_mkdir(ap)
          struct vop_mkdir_args /* {
                  struct vnode *a_dvp;
                  struct vnode **a_vpp;
                  struct componentname *a_cnp;
                  struct vattr *a_vap;
          } */ *ap;
  {
          vattr_t *vap = ap->a_vap;
  
          ASSERT(ap->a_cnp->cn_flags & SAVENAME);
  
          vattr_init_mask(vap);
  
          return (zfs_mkdir(ap->a_dvp, ap->a_cnp->cn_nameptr, vap, ap->a_vpp,
              ap->a_cnp->cn_cred));
  }
  
  static int
  zfs_freebsd_rmdir(ap)
          struct vop_rmdir_args /* {
                  struct vnode *a_dvp;
                  struct vnode *a_vp;
                  struct componentname *a_cnp;
          } */ *ap;
  {
          struct componentname *cnp = ap->a_cnp;
  
          ASSERT(cnp->cn_flags & SAVENAME);
  
          return (zfs_rmdir(ap->a_dvp, ap->a_vp, cnp->cn_nameptr, cnp->cn_cred));
  }
  
  static int
  zfs_freebsd_readdir(ap)
          struct vop_readdir_args /* {
                  struct vnode *a_vp;
                  struct uio *a_uio;
                  struct ucred *a_cred;
                  int *a_eofflag;
                  int *a_ncookies;
                  u_long **a_cookies;
          } */ *ap;
  {
  
          return (zfs_readdir(ap->a_vp, ap->a_uio, ap->a_cred, ap->a_eofflag,
              ap->a_ncookies, ap->a_cookies));
  }
  
  static int
  zfs_freebsd_fsync(ap)
          struct vop_fsync_args /* {
                  struct vnode *a_vp;
                  int a_waitfor;
                  struct thread *a_td;
          } */ *ap;
  {
  
          vop_stdfsync(ap);
          return (zfs_fsync(ap->a_vp, 0, ap->a_td->td_ucred, NULL));
  }
  
  static int
  zfs_freebsd_getattr(ap)
          struct vop_getattr_args /* {
                  struct vnode *a_vp;
                  struct vattr *a_vap;
                  struct ucred *a_cred;
          } */ *ap;
  {
          vattr_t *vap = ap->a_vap;
          xvattr_t xvap;
          u_long fflags = 0;
          int error;
  
          xva_init(&xvap);
          xvap.xva_vattr = *vap;
          xvap.xva_vattr.va_mask |= AT_XVATTR;
  
          /* Convert chflags into ZFS-type flags. */
          /* XXX: what about SF_SETTABLE?. */
          XVA_SET_REQ(&xvap, XAT_IMMUTABLE);
          XVA_SET_REQ(&xvap, XAT_APPENDONLY);
          XVA_SET_REQ(&xvap, XAT_NOUNLINK);
          XVA_SET_REQ(&xvap, XAT_NODUMP);
          XVA_SET_REQ(&xvap, XAT_READONLY);
          XVA_SET_REQ(&xvap, XAT_ARCHIVE);
          XVA_SET_REQ(&xvap, XAT_SYSTEM);
          XVA_SET_REQ(&xvap, XAT_HIDDEN);
          XVA_SET_REQ(&xvap, XAT_REPARSE);
          XVA_SET_REQ(&xvap, XAT_OFFLINE);
          XVA_SET_REQ(&xvap, XAT_SPARSE);
  
          error = zfs_getattr(ap->a_vp, (vattr_t *)&xvap, 0, ap->a_cred, NULL);
          if (error != 0)
                  return (error);
  
          /* Convert ZFS xattr into chflags. */
  #define FLAG_CHECK(fflag, xflag, xfield)        do {                    \
          if (XVA_ISSET_RTN(&xvap, (xflag)) && (xfield) != 0)             \
                  fflags |= (fflag);                                      \
  } while (0)
          FLAG_CHECK(SF_IMMUTABLE, XAT_IMMUTABLE,
              xvap.xva_xoptattrs.xoa_immutable);
          FLAG_CHECK(SF_APPEND, XAT_APPENDONLY,
              xvap.xva_xoptattrs.xoa_appendonly);
          FLAG_CHECK(SF_NOUNLINK, XAT_NOUNLINK,
              xvap.xva_xoptattrs.xoa_nounlink);
          FLAG_CHECK(UF_ARCHIVE, XAT_ARCHIVE,
              xvap.xva_xoptattrs.xoa_archive);
          FLAG_CHECK(UF_NODUMP, XAT_NODUMP,
              xvap.xva_xoptattrs.xoa_nodump);
          FLAG_CHECK(UF_READONLY, XAT_READONLY,
              xvap.xva_xoptattrs.xoa_readonly);
          FLAG_CHECK(UF_SYSTEM, XAT_SYSTEM,
              xvap.xva_xoptattrs.xoa_system);
          FLAG_CHECK(UF_HIDDEN, XAT_HIDDEN,
              xvap.xva_xoptattrs.xoa_hidden);
          FLAG_CHECK(UF_REPARSE, XAT_REPARSE,
              xvap.xva_xoptattrs.xoa_reparse);
          FLAG_CHECK(UF_OFFLINE, XAT_OFFLINE,
              xvap.xva_xoptattrs.xoa_offline);
          FLAG_CHECK(UF_SPARSE, XAT_SPARSE,
              xvap.xva_xoptattrs.xoa_sparse);
  
  #undef  FLAG_CHECK
          *vap = xvap.xva_vattr;
          vap->va_flags = fflags;
          return (0);
  }
  
  static int
  zfs_freebsd_setattr(ap)
          struct vop_setattr_args /* {
                  struct vnode *a_vp;
                  struct vattr *a_vap;
                  struct ucred *a_cred;
          } */ *ap;
  {
          vnode_t *vp = ap->a_vp;
          vattr_t *vap = ap->a_vap;
          cred_t *cred = ap->a_cred;
          xvattr_t xvap;
          u_long fflags;
          uint64_t zflags;
  
          vattr_init_mask(vap);
          vap->va_mask &= ~AT_NOSET;
  
          xva_init(&xvap);
          xvap.xva_vattr = *vap;
  
          zflags = VTOZ(vp)->z_pflags;
  
          if (vap->va_flags != VNOVAL) {
                  zfsvfs_t *zfsvfs = VTOZ(vp)->z_zfsvfs;
                  int error;
  
                  if (zfsvfs->z_use_fuids == B_FALSE)
                          return (EOPNOTSUPP);
  
                  fflags = vap->va_flags;
                  /*
                   * XXX KDM 
                   * We need to figure out whether it makes sense to allow
                   * UF_REPARSE through, since we don't really have other
                   * facilities to handle reparse points and zfs_setattr()
                   * doesn't currently allow setting that attribute anyway.
                   */
                  if ((fflags & ~(SF_IMMUTABLE|SF_APPEND|SF_NOUNLINK|UF_ARCHIVE|
                       UF_NODUMP|UF_SYSTEM|UF_HIDDEN|UF_READONLY|UF_REPARSE|
                       UF_OFFLINE|UF_SPARSE)) != 0)
                          return (EOPNOTSUPP);
                  /*
                   * Unprivileged processes are not permitted to unset system
                   * flags, or modify flags if any system flags are set.
                   * Privileged non-jail processes may not modify system flags
                   * if securelevel > 0 and any existing system flags are set.
                   * Privileged jail processes behave like privileged non-jail
                   * processes if the PR_ALLOW_CHFLAGS permission bit is set;
                   * otherwise, they behave like unprivileged processes.
                   */
                  if (secpolicy_fs_owner(vp->v_mount, cred) == 0 ||
                      priv_check_cred(cred, PRIV_VFS_SYSFLAGS) == 0) {
                          if (zflags &
                              (ZFS_IMMUTABLE | ZFS_APPENDONLY | ZFS_NOUNLINK)) {
                                  error = securelevel_gt(cred, 0);
                                  if (error != 0)
                                          return (error);
                          }
                  } else {
                          /*
                           * Callers may only modify the file flags on objects they
                           * have VADMIN rights for.
                           */
                          if ((error = VOP_ACCESS(vp, VADMIN, cred, curthread)) != 0)
                                  return (error);
                          if (zflags &
                              (ZFS_IMMUTABLE | ZFS_APPENDONLY | ZFS_NOUNLINK)) {
                                  return (EPERM);
                          }
                          if (fflags &
                              (SF_IMMUTABLE | SF_APPEND | SF_NOUNLINK)) {
                                  return (EPERM);
                          }
                  }
  
  #define FLAG_CHANGE(fflag, zflag, xflag, xfield)        do {            \
          if (((fflags & (fflag)) && !(zflags & (zflag))) ||              \
              ((zflags & (zflag)) && !(fflags & (fflag)))) {              \
                  XVA_SET_REQ(&xvap, (xflag));                            \
                  (xfield) = ((fflags & (fflag)) != 0);                   \
          }                                                               \
  } while (0)
                  /* Convert chflags into ZFS-type flags. */
                  /* XXX: what about SF_SETTABLE?. */
                  FLAG_CHANGE(SF_IMMUTABLE, ZFS_IMMUTABLE, XAT_IMMUTABLE,
                      xvap.xva_xoptattrs.xoa_immutable);
                  FLAG_CHANGE(SF_APPEND, ZFS_APPENDONLY, XAT_APPENDONLY,
                      xvap.xva_xoptattrs.xoa_appendonly);
                  FLAG_CHANGE(SF_NOUNLINK, ZFS_NOUNLINK, XAT_NOUNLINK,
                      xvap.xva_xoptattrs.xoa_nounlink);
                  FLAG_CHANGE(UF_ARCHIVE, ZFS_ARCHIVE, XAT_ARCHIVE,
                      xvap.xva_xoptattrs.xoa_archive);
                  FLAG_CHANGE(UF_NODUMP, ZFS_NODUMP, XAT_NODUMP,
                      xvap.xva_xoptattrs.xoa_nodump);
                  FLAG_CHANGE(UF_READONLY, ZFS_READONLY, XAT_READONLY,
                      xvap.xva_xoptattrs.xoa_readonly);
                  FLAG_CHANGE(UF_SYSTEM, ZFS_SYSTEM, XAT_SYSTEM,
                      xvap.xva_xoptattrs.xoa_system);
                  FLAG_CHANGE(UF_HIDDEN, ZFS_HIDDEN, XAT_HIDDEN,
                      xvap.xva_xoptattrs.xoa_hidden);
                  FLAG_CHANGE(UF_REPARSE, ZFS_REPARSE, XAT_REPARSE,
                      xvap.xva_xoptattrs.xoa_hidden);
                  FLAG_CHANGE(UF_OFFLINE, ZFS_OFFLINE, XAT_OFFLINE,
                      xvap.xva_xoptattrs.xoa_offline);
                  FLAG_CHANGE(UF_SPARSE, ZFS_SPARSE, XAT_SPARSE,
                      xvap.xva_xoptattrs.xoa_sparse);
  #undef  FLAG_CHANGE
          }
          if (vap->va_birthtime.tv_sec != VNOVAL) {
                  xvap.xva_vattr.va_mask |= AT_XVATTR;
                  XVA_SET_REQ(&xvap, XAT_CREATETIME);
          }
          return (zfs_setattr(vp, (vattr_t *)&xvap, 0, cred, NULL));
  }
  
  static int
  zfs_freebsd_rename(ap)
          struct vop_rename_args  /* {
                  struct vnode *a_fdvp;
                  struct vnode *a_fvp;
                  struct componentname *a_fcnp;
                  struct vnode *a_tdvp;
                  struct vnode *a_tvp;
                  struct componentname *a_tcnp;
          } */ *ap;
  {
          vnode_t *fdvp = ap->a_fdvp;
          vnode_t *fvp = ap->a_fvp;
          vnode_t *tdvp = ap->a_tdvp;
          vnode_t *tvp = ap->a_tvp;
          int error;
  
          ASSERT(ap->a_fcnp->cn_flags & (SAVENAME|SAVESTART));
          ASSERT(ap->a_tcnp->cn_flags & (SAVENAME|SAVESTART));
  
          error = zfs_rename(fdvp, &fvp, ap->a_fcnp, tdvp, &tvp,
              ap->a_tcnp, ap->a_fcnp->cn_cred);
  
          vrele(fdvp);
          vrele(fvp);
          vrele(tdvp);
          if (tvp != NULL)
                  vrele(tvp);
  
          return (error);
  }
  
  static int
  zfs_freebsd_symlink(ap)
          struct vop_symlink_args /* {
                  struct vnode *a_dvp;
                  struct vnode **a_vpp;
                  struct componentname *a_cnp;
                  struct vattr *a_vap;
                  char *a_target;
          } */ *ap;
  {
          struct componentname *cnp = ap->a_cnp;
          vattr_t *vap = ap->a_vap;
  
          ASSERT(cnp->cn_flags & SAVENAME);
  
          vap->va_type = VLNK;    /* FreeBSD: Syscall only sets va_mode. */
          vattr_init_mask(vap);
  
          return (zfs_symlink(ap->a_dvp, ap->a_vpp, cnp->cn_nameptr, vap,
              __DECONST(char *, ap->a_target), cnp->cn_cred, cnp->cn_thread));
  }
  
  static int
  zfs_freebsd_readlink(ap)
          struct vop_readlink_args /* {
                  struct vnode *a_vp;
                  struct uio *a_uio;
                  struct ucred *a_cred;
          } */ *ap;
  {
  
          return (zfs_readlink(ap->a_vp, ap->a_uio, ap->a_cred, NULL));
  }
  
  static int
  zfs_freebsd_link(ap)
          struct vop_link_args /* {
                  struct vnode *a_tdvp;
                  struct vnode *a_vp;
                  struct componentname *a_cnp;
          } */ *ap;
  {
          struct componentname *cnp = ap->a_cnp;
          vnode_t *vp = ap->a_vp;
          vnode_t *tdvp = ap->a_tdvp;
  
          if (tdvp->v_mount != vp->v_mount)
                  return (EXDEV);
  
          ASSERT(cnp->cn_flags & SAVENAME);
  
          return (zfs_link(tdvp, vp, cnp->cn_nameptr, cnp->cn_cred, NULL, 0));
  }
  
  static int
  zfs_freebsd_inactive(ap)
          struct vop_inactive_args /* {
                  struct vnode *a_vp;
                  struct thread *a_td;
          } */ *ap;
  {
          vnode_t *vp = ap->a_vp;
  
          zfs_inactive(vp, ap->a_td->td_ucred, NULL);
          return (0);
  }
  
  static int
  zfs_freebsd_reclaim(ap)
          struct vop_reclaim_args /* {
                  struct vnode *a_vp;
                  struct thread *a_td;
          } */ *ap;
  {
          vnode_t *vp = ap->a_vp;
          znode_t *zp = VTOZ(vp);
          zfsvfs_t *zfsvfs = zp->z_zfsvfs;
  
          ASSERT(zp != NULL);
  
          /* Destroy the vm object and flush associated pages. */
          vnode_destroy_vobject(vp);
  
          /*
           * z_teardown_inactive_lock protects from a race with
           * zfs_znode_dmu_fini in zfsvfs_teardown during
           * force unmount.
           */
          rw_enter(&zfsvfs->z_teardown_inactive_lock, RW_READER);
          if (zp->z_sa_hdl == NULL)
                  zfs_znode_free(zp);
          else
                  zfs_zinactive(zp);
          rw_exit(&zfsvfs->z_teardown_inactive_lock);
  
          vp->v_data = NULL;
          return (0);
  }
  
  static int
  zfs_freebsd_fid(ap)
          struct vop_fid_args /* {
                  struct vnode *a_vp;
                  struct fid *a_fid;
          } */ *ap;
  {
  
          return (zfs_fid(ap->a_vp, (void *)ap->a_fid, NULL));
  }
  
  static int
  zfs_freebsd_pathconf(ap)
          struct vop_pathconf_args /* {
                  struct vnode *a_vp;
                  int a_name;
                  register_t *a_retval;
          } */ *ap;
  {
          ulong_t val;
          int error;
  
          error = zfs_pathconf(ap->a_vp, ap->a_name, &val, curthread->td_ucred, NULL);
          if (error == 0) {
                  *ap->a_retval = val;
                  return (error);
          }
          if (error != EOPNOTSUPP)
                  return (error);
  
          switch (ap->a_name) {
          case _PC_NAME_MAX:
                  *ap->a_retval = NAME_MAX;
                  return (0);
          case _PC_PIPE_BUF:
                  if (ap->a_vp->v_type == VDIR || ap->a_vp->v_type == VFIFO) {
                          *ap->a_retval = PIPE_BUF;
                          return (0);
                  }
                  return (EINVAL);
          default:
                  return (vop_stdpathconf(ap));
          }
  }
  
  /*
   * FreeBSD's extended attributes namespace defines file name prefix for ZFS'
   * extended attribute name:
   *
   *      NAMESPACE       PREFIX  
   *      system          freebsd:system:
   *      user            (none, can be used to access ZFS fsattr(5) attributes
   *                      created on Solaris)
   */
  static int
  zfs_create_attrname(int attrnamespace, const char *name, char *attrname,
      size_t size)
  {
          const char *namespace, *prefix, *suffix;
  
          /* We don't allow '/' character in attribute name. */
          if (strchr(name, '/') != NULL)
                  return (EINVAL);
          /* We don't allow attribute names that start with "freebsd:" string. */
          if (strncmp(name, "freebsd:", 8) == 0)
                  return (EINVAL);
  
          bzero(attrname, size);
  
          switch (attrnamespace) {
          case EXTATTR_NAMESPACE_USER:
  #if 0
                  prefix = "freebsd:";
                  namespace = EXTATTR_NAMESPACE_USER_STRING;
                  suffix = ":";
  #else
                  /*
                   * This is the default namespace by which we can access all
                   * attributes created on Solaris.
                   */
                  prefix = namespace = suffix = "";
  #endif
                  break;
          case EXTATTR_NAMESPACE_SYSTEM:
                  prefix = "freebsd:";
                  namespace = EXTATTR_NAMESPACE_SYSTEM_STRING;
                  suffix = ":";
                  break;
          case EXTATTR_NAMESPACE_EMPTY:
          default:
                  return (EINVAL);
          }
          if (snprintf(attrname, size, "%s%s%s%s", prefix, namespace, suffix,
              name) >= size) {
                  return (ENAMETOOLONG);
          }
          return (0);
  }
  
  /*
   * Vnode operating to retrieve a named extended attribute.
   */
  static int
  zfs_getextattr(struct vop_getextattr_args *ap)
  /*
  vop_getextattr {
          IN struct vnode *a_vp;
          IN int a_attrnamespace;
          IN const char *a_name;
          INOUT struct uio *a_uio;
          OUT size_t *a_size;
          IN struct ucred *a_cred;
          IN struct thread *a_td;
  };
  */
  {
          zfsvfs_t *zfsvfs = VTOZ(ap->a_vp)->z_zfsvfs;
          struct thread *td = ap->a_td;
          struct nameidata nd;
          char attrname[255];
          struct vattr va;
          vnode_t *xvp = NULL, *vp;
          int error, flags;
  
          error = extattr_check_cred(ap->a_vp, ap->a_attrnamespace,
              ap->a_cred, ap->a_td, VREAD);
          if (error != 0)
                  return (error);
  
          error = zfs_create_attrname(ap->a_attrnamespace, ap->a_name, attrname,
              sizeof(attrname));
          if (error != 0)
                  return (error);
  
          ZFS_ENTER(zfsvfs);
  
          error = zfs_lookup(ap->a_vp, NULL, &xvp, NULL, 0, ap->a_cred, td,
              LOOKUP_XATTR);
          if (error != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          flags = FREAD;
          NDINIT_ATVP(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, attrname,
              xvp, td);
          error = vn_open_cred(&nd, &flags, 0, 0, ap->a_cred, NULL);
          vp = nd.ni_vp;
          NDFREE(&nd, NDF_ONLY_PNBUF);
          if (error != 0) {
                  ZFS_EXIT(zfsvfs);
                  if (error == ENOENT)
                          error = ENOATTR;
                  return (error);
          }
  
          if (ap->a_size != NULL) {
                  error = VOP_GETATTR(vp, &va, ap->a_cred);
                  if (error == 0)
                          *ap->a_size = (size_t)va.va_size;
          } else if (ap->a_uio != NULL)
                  error = VOP_READ(vp, ap->a_uio, IO_UNIT, ap->a_cred);
  
          VOP_UNLOCK(vp, 0);
          vn_close(vp, flags, ap->a_cred, td);
          ZFS_EXIT(zfsvfs);
  
          return (error);
  }
  
  /*
   * Vnode operation to remove a named attribute.
   */
  int
  zfs_deleteextattr(struct vop_deleteextattr_args *ap)
  /*
  vop_deleteextattr {
          IN struct vnode *a_vp;
          IN int a_attrnamespace;
          IN const char *a_name;
          IN struct ucred *a_cred;
          IN struct thread *a_td;
  };
  */
  {
          zfsvfs_t *zfsvfs = VTOZ(ap->a_vp)->z_zfsvfs;
          struct thread *td = ap->a_td;
          struct nameidata nd;
          char attrname[255];
          struct vattr va;
          vnode_t *xvp = NULL, *vp;
          int error, flags;
  
          error = extattr_check_cred(ap->a_vp, ap->a_attrnamespace,
              ap->a_cred, ap->a_td, VWRITE);
          if (error != 0)
                  return (error);
  
          error = zfs_create_attrname(ap->a_attrnamespace, ap->a_name, attrname,
              sizeof(attrname));
          if (error != 0)
                  return (error);
  
          ZFS_ENTER(zfsvfs);
  
          error = zfs_lookup(ap->a_vp, NULL, &xvp, NULL, 0, ap->a_cred, td,
              LOOKUP_XATTR);
          if (error != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          NDINIT_ATVP(&nd, DELETE, NOFOLLOW | LOCKPARENT | LOCKLEAF,
              UIO_SYSSPACE, attrname, xvp, td);
          error = namei(&nd);
          vp = nd.ni_vp;
          if (error != 0) {
                  ZFS_EXIT(zfsvfs);
                  NDFREE(&nd, NDF_ONLY_PNBUF);
                  if (error == ENOENT)
                          error = ENOATTR;
                  return (error);
          }
  
          error = VOP_REMOVE(nd.ni_dvp, vp, &nd.ni_cnd);
          NDFREE(&nd, NDF_ONLY_PNBUF);
  
          vput(nd.ni_dvp);
          if (vp == nd.ni_dvp)
                  vrele(vp);
          else
                  vput(vp);
          ZFS_EXIT(zfsvfs);
  
          return (error);
  }
  
  /*
   * Vnode operation to set a named attribute.
   */
  static int
  zfs_setextattr(struct vop_setextattr_args *ap)
  /*
  vop_setextattr {
          IN struct vnode *a_vp;
          IN int a_attrnamespace;
          IN const char *a_name;
          INOUT struct uio *a_uio;
          IN struct ucred *a_cred;
          IN struct thread *a_td;
  };
  */
  {
          zfsvfs_t *zfsvfs = VTOZ(ap->a_vp)->z_zfsvfs;
          struct thread *td = ap->a_td;
          struct nameidata nd;
          char attrname[255];
          struct vattr va;
          vnode_t *xvp = NULL, *vp;
          int error, flags;
  
          error = extattr_check_cred(ap->a_vp, ap->a_attrnamespace,
              ap->a_cred, ap->a_td, VWRITE);
          if (error != 0)
                  return (error);
  
          error = zfs_create_attrname(ap->a_attrnamespace, ap->a_name, attrname,
              sizeof(attrname));
          if (error != 0)
                  return (error);
  
          ZFS_ENTER(zfsvfs);
  
          error = zfs_lookup(ap->a_vp, NULL, &xvp, NULL, 0, ap->a_cred, td,
              LOOKUP_XATTR | CREATE_XATTR_DIR);
          if (error != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          flags = FFLAGS(O_WRONLY | O_CREAT);
          NDINIT_ATVP(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, attrname,
              xvp, td);
          error = vn_open_cred(&nd, &flags, 0600, 0, ap->a_cred, NULL);
          vp = nd.ni_vp;
          NDFREE(&nd, NDF_ONLY_PNBUF);
          if (error != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          VATTR_NULL(&va);
          va.va_size = 0;
          error = VOP_SETATTR(vp, &va, ap->a_cred);
          if (error == 0)
                  VOP_WRITE(vp, ap->a_uio, IO_UNIT, ap->a_cred);
  
          VOP_UNLOCK(vp, 0);
          vn_close(vp, flags, ap->a_cred, td);
          ZFS_EXIT(zfsvfs);
  
          return (error);
  }
  
  /*
   * Vnode operation to retrieve extended attributes on a vnode.
   */
  static int
  zfs_listextattr(struct vop_listextattr_args *ap)
  /*
  vop_listextattr {
          IN struct vnode *a_vp;
          IN int a_attrnamespace;
          INOUT struct uio *a_uio;
          OUT size_t *a_size;
          IN struct ucred *a_cred;
          IN struct thread *a_td;
  };
  */
  {
          zfsvfs_t *zfsvfs = VTOZ(ap->a_vp)->z_zfsvfs;
          struct thread *td = ap->a_td;
          struct nameidata nd;
          char attrprefix[16];
          u_char dirbuf[sizeof(struct dirent)];
          struct dirent *dp;
          struct iovec aiov;
          struct uio auio, *uio = ap->a_uio;
          size_t *sizep = ap->a_size;
          size_t plen;
          vnode_t *xvp = NULL, *vp;
          int done, error, eof, pos;
  
          error = extattr_check_cred(ap->a_vp, ap->a_attrnamespace,
              ap->a_cred, ap->a_td, VREAD);
          if (error != 0)
                  return (error);
  
          error = zfs_create_attrname(ap->a_attrnamespace, "", attrprefix,
              sizeof(attrprefix));
          if (error != 0)
                  return (error);
          plen = strlen(attrprefix);
  
          ZFS_ENTER(zfsvfs);
  
          if (sizep != NULL)
                  *sizep = 0;
  
          error = zfs_lookup(ap->a_vp, NULL, &xvp, NULL, 0, ap->a_cred, td,
              LOOKUP_XATTR);
          if (error != 0) {
                  ZFS_EXIT(zfsvfs);
                  /*
                   * ENOATTR means that the EA directory does not yet exist,
                   * i.e. there are no extended attributes there.
                   */
                  if (error == ENOATTR)
                          error = 0;
                  return (error);
          }
  
          NDINIT_ATVP(&nd, LOOKUP, NOFOLLOW | LOCKLEAF | LOCKSHARED,
              UIO_SYSSPACE, ".", xvp, td);
          error = namei(&nd);
          vp = nd.ni_vp;
          NDFREE(&nd, NDF_ONLY_PNBUF);
          if (error != 0) {
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
  
          auio.uio_iov = &aiov;
          auio.uio_iovcnt = 1;
          auio.uio_segflg = UIO_SYSSPACE;
          auio.uio_td = td;
          auio.uio_rw = UIO_READ;
          auio.uio_offset = 0;
  
          do {
                  u_char nlen;
  
                  aiov.iov_base = (void *)dirbuf;
                  aiov.iov_len = sizeof(dirbuf);
                  auio.uio_resid = sizeof(dirbuf);
                  error = VOP_READDIR(vp, &auio, ap->a_cred, &eof, NULL, NULL);
                  done = sizeof(dirbuf) - auio.uio_resid;
                  if (error != 0)
                          break;
                  for (pos = 0; pos < done;) {
                          dp = (struct dirent *)(dirbuf + pos);
                          pos += dp->d_reclen;
                          /*
                           * XXX: Temporarily we also accept DT_UNKNOWN, as this
                           * is what we get when attribute was created on Solaris.
                           */
                          if (dp->d_type != DT_REG && dp->d_type != DT_UNKNOWN)
                                  continue;
                          if (plen == 0 && strncmp(dp->d_name, "freebsd:", 8) == 0)
                                  continue;
                          else if (strncmp(dp->d_name, attrprefix, plen) != 0)
                                  continue;
                          nlen = dp->d_namlen - plen;
                          if (sizep != NULL)
                                  *sizep += 1 + nlen;
                          else if (uio != NULL) {
                                  /*
                                   * Format of extattr name entry is one byte for
                                   * length and the rest for name.
                                   */
                                  error = uiomove(&nlen, 1, uio->uio_rw, uio);
                                  if (error == 0) {
                                          error = uiomove(dp->d_name + plen, nlen,
                                              uio->uio_rw, uio);
                                  }
                                  if (error != 0)
                                          break;
                          }
                  }
          } while (!eof && error == 0);
  
          vput(vp);
          ZFS_EXIT(zfsvfs);
  
          return (error);
  }
  
  int
  zfs_freebsd_getacl(ap)
          struct vop_getacl_args /* {
                  struct vnode *vp;
                  acl_type_t type;
                  struct acl *aclp;
                  struct ucred *cred;
                  struct thread *td;
          } */ *ap;
  {
          int             error;
          vsecattr_t      vsecattr;
  
          if (ap->a_type != ACL_TYPE_NFS4)
                  return (EINVAL);
  
          vsecattr.vsa_mask = VSA_ACE | VSA_ACECNT;
          if (error = zfs_getsecattr(ap->a_vp, &vsecattr, 0, ap->a_cred, NULL))
                  return (error);
  
          error = acl_from_aces(ap->a_aclp, vsecattr.vsa_aclentp, vsecattr.vsa_aclcnt);
          if (vsecattr.vsa_aclentp != NULL)
                  kmem_free(vsecattr.vsa_aclentp, vsecattr.vsa_aclentsz);
  
          return (error);
  }
  
  int
  zfs_freebsd_setacl(ap)
          struct vop_setacl_args /* {
                  struct vnode *vp;
                  acl_type_t type;
                  struct acl *aclp;
                  struct ucred *cred;
                  struct thread *td;
          } */ *ap;
  {
          int             error;
          vsecattr_t      vsecattr;
          int             aclbsize;       /* size of acl list in bytes */
          aclent_t        *aaclp;
  
          if (ap->a_type != ACL_TYPE_NFS4)
                  return (EINVAL);
  
          if (ap->a_aclp == NULL)
                  return (EINVAL);
  
          if (ap->a_aclp->acl_cnt < 1 || ap->a_aclp->acl_cnt > MAX_ACL_ENTRIES)
                  return (EINVAL);
  
          /*
           * With NFSv4 ACLs, chmod(2) may need to add additional entries,
           * splitting every entry into two and appending "canonical six"
           * entries at the end.  Don't allow for setting an ACL that would
           * cause chmod(2) to run out of ACL entries.
           */
          if (ap->a_aclp->acl_cnt * 2 + 6 > ACL_MAX_ENTRIES)
                  return (ENOSPC);
  
          error = acl_nfs4_check(ap->a_aclp, ap->a_vp->v_type == VDIR);
          if (error != 0)
                  return (error);
  
          vsecattr.vsa_mask = VSA_ACE;
          aclbsize = ap->a_aclp->acl_cnt * sizeof(ace_t);
          vsecattr.vsa_aclentp = kmem_alloc(aclbsize, KM_SLEEP);
          aaclp = vsecattr.vsa_aclentp;
          vsecattr.vsa_aclentsz = aclbsize;
  
          aces_from_acl(vsecattr.vsa_aclentp, &vsecattr.vsa_aclcnt, ap->a_aclp);
          error = zfs_setsecattr(ap->a_vp, &vsecattr, 0, ap->a_cred, NULL);
          kmem_free(aaclp, aclbsize);
  
          return (error);
  }
  
  int
  zfs_freebsd_aclcheck(ap)
          struct vop_aclcheck_args /* {
                  struct vnode *vp;
                  acl_type_t type;
                  struct acl *aclp;
                  struct ucred *cred;
                  struct thread *td;
          } */ *ap;
  {
  
          return (EOPNOTSUPP);
  }
  
  static int
  zfs_vptocnp(struct vop_vptocnp_args *ap)
  {
          vnode_t *covered_vp;
          vnode_t *vp = ap->a_vp;;
          zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
          znode_t *zp = VTOZ(vp);
          int ltype;
          int error;
  
          ZFS_ENTER(zfsvfs);
          ZFS_VERIFY_ZP(zp);
  
          /*
           * If we are a snapshot mounted under .zfs, run the operation
           * on the covered vnode.
           */
          if (zp->z_id != zfsvfs->z_root || zfsvfs->z_parent == zfsvfs) {
                  char name[MAXNAMLEN + 1];
                  znode_t *dzp;
                  size_t len;
  
                  error = zfs_znode_parent_and_name(zp, &dzp, name);
                  if (error == 0) {
                          len = strlen(name);
                          if (*ap->a_buflen < len)
                                  error = SET_ERROR(ENOMEM);
                  }
                  if (error == 0) {
                          *ap->a_buflen -= len;
                          bcopy(name, ap->a_buf + *ap->a_buflen, len);
                          *ap->a_vpp = ZTOV(dzp);
                  }
                  ZFS_EXIT(zfsvfs);
                  return (error);
          }
          ZFS_EXIT(zfsvfs);
  
          covered_vp = vp->v_mount->mnt_vnodecovered;
          vhold(covered_vp);
          ltype = VOP_ISLOCKED(vp);
          VOP_UNLOCK(vp, 0);
          error = vget(covered_vp, LK_SHARED | LK_VNHELD, curthread);
          if (error == 0) {
                  error = VOP_VPTOCNP(covered_vp, ap->a_vpp, ap->a_cred,
                      ap->a_buf, ap->a_buflen);
                  vput(covered_vp);
          }
          vn_lock(vp, ltype | LK_RETRY);
          if ((vp->v_iflag & VI_DOOMED) != 0)
                  error = SET_ERROR(ENOENT);
          return (error);
  }
  
  #ifdef DIAGNOSTIC
  static int
  zfs_lock(ap)
          struct vop_lock1_args /* {
                  struct vnode *a_vp;
                  int a_flags;
                  char *file;
                  int line;
          } */ *ap;
  {
          vnode_t *vp;
          znode_t *zp;
          int err;
  
          err = vop_stdlock(ap);
          if (err == 0 && (ap->a_flags & LK_NOWAIT) == 0) {
                  vp = ap->a_vp;
                  zp = vp->v_data;
                  if (vp->v_mount != NULL && (vp->v_iflag & VI_DOOMED) == 0 &&
                      zp != NULL && (zp->z_pflags & ZFS_XATTR) == 0)
                          VERIFY(!RRM_LOCK_HELD(&zp->z_zfsvfs->z_teardown_lock));
          }
          return (err);
  }
  #endif
  
  struct vop_vector zfs_vnodeops;
  struct vop_vector zfs_fifoops;
  struct vop_vector zfs_shareops;
  
  struct vop_vector zfs_vnodeops = {
          .vop_default =          &default_vnodeops,
          .vop_inactive =         zfs_freebsd_inactive,
          .vop_reclaim =          zfs_freebsd_reclaim,
          .vop_access =           zfs_freebsd_access,
          .vop_allocate =         VOP_EINVAL,
          .vop_lookup =           zfs_cache_lookup,
          .vop_cachedlookup =     zfs_freebsd_lookup,
          .vop_getattr =          zfs_freebsd_getattr,
          .vop_setattr =          zfs_freebsd_setattr,
          .vop_create =           zfs_freebsd_create,
          .vop_mknod =            zfs_freebsd_create,
          .vop_mkdir =            zfs_freebsd_mkdir,
          .vop_readdir =          zfs_freebsd_readdir,
          .vop_fsync =            zfs_freebsd_fsync,
          .vop_open =             zfs_freebsd_open,
          .vop_close =            zfs_freebsd_close,
          .vop_rmdir =            zfs_freebsd_rmdir,
          .vop_ioctl =            zfs_freebsd_ioctl,
          .vop_link =             zfs_freebsd_link,
          .vop_symlink =          zfs_freebsd_symlink,
          .vop_readlink =         zfs_freebsd_readlink,
          .vop_read =             zfs_freebsd_read,
          .vop_write =            zfs_freebsd_write,
          .vop_remove =           zfs_freebsd_remove,
          .vop_rename =           zfs_freebsd_rename,
          .vop_pathconf =         zfs_freebsd_pathconf,
          .vop_bmap =             zfs_freebsd_bmap,
          .vop_fid =              zfs_freebsd_fid,
          .vop_getextattr =       zfs_getextattr,
          .vop_deleteextattr =    zfs_deleteextattr,
          .vop_setextattr =       zfs_setextattr,
          .vop_listextattr =      zfs_listextattr,
          .vop_getacl =           zfs_freebsd_getacl,
          .vop_setacl =           zfs_freebsd_setacl,
          .vop_aclcheck =         zfs_freebsd_aclcheck,
          .vop_getpages =         zfs_freebsd_getpages,
          .vop_putpages =         zfs_freebsd_putpages,
          .vop_vptocnp =          zfs_vptocnp,
  #ifdef DIAGNOSTIC
          .vop_lock1 =            zfs_lock,
  #endif
  };
  
  struct vop_vector zfs_fifoops = {
          .vop_default =          &fifo_specops,
          .vop_fsync =            zfs_freebsd_fsync,
          .vop_access =           zfs_freebsd_access,
          .vop_getattr =          zfs_freebsd_getattr,
          .vop_inactive =         zfs_freebsd_inactive,
          .vop_read =             VOP_PANIC,
          .vop_reclaim =          zfs_freebsd_reclaim,
          .vop_setattr =          zfs_freebsd_setattr,
          .vop_write =            VOP_PANIC,
          .vop_pathconf =         zfs_freebsd_pathconf,
          .vop_fid =              zfs_freebsd_fid,
          .vop_getacl =           zfs_freebsd_getacl,
          .vop_setacl =           zfs_freebsd_setacl,
          .vop_aclcheck =         zfs_freebsd_aclcheck,
  };
  
  /*
   * special share hidden files vnode operations template
   */
  struct vop_vector zfs_shareops = {
          .vop_default =          &default_vnodeops,
          .vop_access =           zfs_freebsd_access,
          .vop_inactive =         zfs_freebsd_inactive,
          .vop_reclaim =          zfs_freebsd_reclaim,
          .vop_fid =              zfs_freebsd_fid,
          .vop_pathconf =         zfs_freebsd_pathconf,
  };