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zfs_znode.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 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/* Portions Copyright 2007 Jeremy Teo */

#ifdef _KERNEL
#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/mntent.h>
#include <sys/mkdev.h>
#include <sys/u8_textprep.h>
#include <sys/dsl_dataset.h>
#include <sys/vfs.h>
#include <sys/vfs_opreg.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/kmem.h>
#include <sys/errno.h>
#include <sys/unistd.h>
#include <sys/mode.h>
#include <sys/atomic.h>
#include <vm/pvn.h>
#include "fs/fs_subr.h"
#include <sys/zfs_dir.h>
#include <sys/zfs_acl.h>
#include <sys/zfs_ioctl.h>
#include <sys/zfs_rlock.h>
#include <sys/zfs_fuid.h>
#include <sys/fs/zfs.h>
#include <sys/kidmap.h>

kmem_cache_t *znode_cache = NULL;
#endif /* _KERNEL */

#include <sys/dmu.h>
#include <sys/refcount.h>
#include <sys/stat.h>
#include <sys/zap.h>
#include <sys/zfs_znode.h>

#include "zfs_prop.h"

/*
 * Define ZNODE_STATS to turn on statistic gathering. By default, it is only
 * turned on when DEBUG is also defined.
 */
#ifdef      DEBUG
#define     ZNODE_STATS
#endif      /* DEBUG */

#ifdef      ZNODE_STATS
#define     ZNODE_STAT_ADD(stat)                ((stat)++)
#else
#define     ZNODE_STAT_ADD(stat)                /* nothing */
#endif      /* ZNODE_STATS */

/* ZFSFUSE: libumem isn't setting 0xdeadbeef or 0xbaddcafe */
/*#define   POINTER_IS_VALID(p)     (!((uintptr_t)(p) & 0x3))*/
#define     POINTER_INVALIDATE(pp)  (*(pp) = (void *)((uintptr_t)(*(pp)) | 0x1))

/*
 * Functions needed for userland (ie: libzpool) are not put under
 * #ifdef_KERNEL; the rest of the functions have dependencies
 * (such as VFS logic) that will not compile easily in userland.
 */
#ifdef _KERNEL

/*ARGSUSED*/
static void
znode_evict_error(dmu_buf_t *dbuf, void *user_ptr)
{
      /*
       * We should never drop all dbuf refs without first clearing
       * the eviction callback.
       */
      panic("evicting znode %p\n", user_ptr);
}

/*ARGSUSED*/
static int
zfs_znode_cache_constructor(void *buf, void *arg, int kmflags)
{
      znode_t *zp = buf;

      /* ZFSFUSE */
      /* ASSERT(!POINTER_IS_VALID(zp->z_zfsvfs)); */

      zp->z_vnode = vn_alloc(kmflags);
      if (zp->z_vnode == NULL) {
            return (-1);
      }
      ZTOV(zp)->v_data = zp;

      list_link_init(&zp->z_link_node);

      mutex_init(&zp->z_lock, NULL, MUTEX_DEFAULT, NULL);
      rw_init(&zp->z_parent_lock, NULL, RW_DEFAULT, NULL);
      rw_init(&zp->z_name_lock, NULL, RW_DEFAULT, NULL);
      mutex_init(&zp->z_acl_lock, NULL, MUTEX_DEFAULT, NULL);

      mutex_init(&zp->z_range_lock, NULL, MUTEX_DEFAULT, NULL);
      avl_create(&zp->z_range_avl, zfs_range_compare,
          sizeof (rl_t), offsetof(rl_t, r_node));

      zp->z_dbuf = NULL;
      zp->z_dirlocks = NULL;
      return (0);
}

/*ARGSUSED*/
static void
zfs_znode_cache_destructor(void *buf, void *arg)
{
      znode_t *zp = buf;

      /* ZFSFUSE */
      /* ASSERT(!POINTER_IS_VALID(zp->z_zfsvfs)); */
      ASSERT(ZTOV(zp)->v_data == zp);
      vn_free(ZTOV(zp));
      ASSERT(!list_link_active(&zp->z_link_node));
      mutex_destroy(&zp->z_lock);
      rw_destroy(&zp->z_parent_lock);
      rw_destroy(&zp->z_name_lock);
      mutex_destroy(&zp->z_acl_lock);
      avl_destroy(&zp->z_range_avl);
      mutex_destroy(&zp->z_range_lock);

      ASSERT(zp->z_dbuf == NULL);
      ASSERT(zp->z_dirlocks == NULL);
}

#ifdef      ZNODE_STATS
static struct {
      uint64_t zms_zfsvfs_invalid;
      uint64_t zms_zfsvfs_unmounted;
      uint64_t zms_zfsvfs_recheck_invalid;
      uint64_t zms_obj_held;
      uint64_t zms_vnode_locked;
      uint64_t zms_not_only_dnlc;
} znode_move_stats;
#endif      /* ZNODE_STATS */

/* ZFSFUSE: not needed */
#if 0
static void
zfs_znode_move_impl(znode_t *ozp, znode_t *nzp)
{
      vnode_t *vp;

      /* Copy fields. */
      nzp->z_zfsvfs = ozp->z_zfsvfs;

      /* Swap vnodes. */
      vp = nzp->z_vnode;
      nzp->z_vnode = ozp->z_vnode;
      ozp->z_vnode = vp; /* let destructor free the overwritten vnode */
      ZTOV(ozp)->v_data = ozp;
      ZTOV(nzp)->v_data = nzp;

      nzp->z_id = ozp->z_id;
      ASSERT(ozp->z_dirlocks == NULL); /* znode not in use */
      ASSERT(avl_numnodes(&ozp->z_range_avl) == 0);
      nzp->z_unlinked = ozp->z_unlinked;
      nzp->z_atime_dirty = ozp->z_atime_dirty;
      nzp->z_zn_prefetch = ozp->z_zn_prefetch;
      nzp->z_blksz = ozp->z_blksz;
      nzp->z_seq = ozp->z_seq;
      nzp->z_mapcnt = ozp->z_mapcnt;
      nzp->z_last_itx = ozp->z_last_itx;
      nzp->z_gen = ozp->z_gen;
      nzp->z_sync_cnt = ozp->z_sync_cnt;
      nzp->z_phys = ozp->z_phys;
      nzp->z_dbuf = ozp->z_dbuf;

      /* Update back pointers. */
      (void) dmu_buf_update_user(nzp->z_dbuf, ozp, nzp, &nzp->z_phys,
          znode_evict_error);

      /*
       * Invalidate the original znode by clearing fields that provide a
       * pointer back to the znode. Set the low bit of the vfs pointer to
       * ensure that zfs_znode_move() recognizes the znode as invalid in any
       * subsequent callback.
       */
      ozp->z_dbuf = NULL;
      POINTER_INVALIDATE(&ozp->z_zfsvfs);
}
#endif

/* ZFSFUSE: not needed */
#if 0
/*ARGSUSED*/
static kmem_cbrc_t
zfs_znode_move(void *buf, void *newbuf, size_t size, void *arg)
{
      znode_t *ozp = buf, *nzp = newbuf;
      zfsvfs_t *zfsvfs;
      vnode_t *vp;

      /*
       * The znode is on the file system's list of known znodes if the vfs
       * pointer is valid. We set the low bit of the vfs pointer when freeing
       * the znode to invalidate it, and the memory patterns written by kmem
       * (baddcafe and deadbeef) set at least one of the two low bits. A newly
       * created znode sets the vfs pointer last of all to indicate that the
       * znode is known and in a valid state to be moved by this function.
       */
      zfsvfs = ozp->z_zfsvfs;
      if (!POINTER_IS_VALID(zfsvfs)) {
            ZNODE_STAT_ADD(znode_move_stats.zms_zfsvfs_invalid);
            return (KMEM_CBRC_DONT_KNOW);
      }

      /*
       * Ensure that the filesystem is not unmounted during the move.
       * This is the equivalent to ZFS_ENTER().
       */
      rrw_enter(&zfsvfs->z_teardown_lock, RW_READER, FTAG);
      if (zfsvfs->z_unmounted) {
            ZFS_EXIT(zfsvfs);
            ZNODE_STAT_ADD(znode_move_stats.zms_zfsvfs_unmounted);
            return (KMEM_CBRC_DONT_KNOW);
      }

      mutex_enter(&zfsvfs->z_znodes_lock);
      /*
       * Recheck the vfs pointer in case the znode was removed just before
       * acquiring the lock.
       */
      if (zfsvfs != ozp->z_zfsvfs) {
            mutex_exit(&zfsvfs->z_znodes_lock);
            ZFS_EXIT(zfsvfs);
            ZNODE_STAT_ADD(znode_move_stats.zms_zfsvfs_recheck_invalid);
            return (KMEM_CBRC_DONT_KNOW);
      }

      /*
       * At this point we know that as long as we hold z_znodes_lock, the
       * znode cannot be freed and fields within the znode can be safely
       * accessed. Now, prevent a race with zfs_zget().
       */
      if (ZFS_OBJ_HOLD_TRYENTER(zfsvfs, ozp->z_id) == 0) {
            mutex_exit(&zfsvfs->z_znodes_lock);
            ZFS_EXIT(zfsvfs);
            ZNODE_STAT_ADD(znode_move_stats.zms_obj_held);
            return (KMEM_CBRC_LATER);
      }

      vp = ZTOV(ozp);
      if (mutex_tryenter(&vp->v_lock) == 0) {
            ZFS_OBJ_HOLD_EXIT(zfsvfs, ozp->z_id);
            mutex_exit(&zfsvfs->z_znodes_lock);
            ZFS_EXIT(zfsvfs);
            ZNODE_STAT_ADD(znode_move_stats.zms_vnode_locked);
            return (KMEM_CBRC_LATER);
      }

      /* Only move znodes that are referenced _only_ by the DNLC. */
      if (vp->v_count != 1 || !vn_in_dnlc(vp)) {
            mutex_exit(&vp->v_lock);
            ZFS_OBJ_HOLD_EXIT(zfsvfs, ozp->z_id);
            mutex_exit(&zfsvfs->z_znodes_lock);
            ZFS_EXIT(zfsvfs);
            ZNODE_STAT_ADD(znode_move_stats.zms_not_only_dnlc);
            return (KMEM_CBRC_LATER);
      }

      /*
       * The znode is known and in a valid state to move. We're holding the
       * locks needed to execute the critical section.
       */
      zfs_znode_move_impl(ozp, nzp);
      mutex_exit(&vp->v_lock);
      ZFS_OBJ_HOLD_EXIT(zfsvfs, ozp->z_id);

      list_link_replace(&ozp->z_link_node, &nzp->z_link_node);
      mutex_exit(&zfsvfs->z_znodes_lock);
      ZFS_EXIT(zfsvfs);

      return (KMEM_CBRC_YES);
}
#endif

void
zfs_znode_init(void)
{
      /*
       * Initialize zcache
       */
      ASSERT(znode_cache == NULL);
      znode_cache = kmem_cache_create("zfs_znode_cache",
          sizeof (znode_t), 0, zfs_znode_cache_constructor,
          zfs_znode_cache_destructor, NULL, NULL, NULL, 0);
      /* ZFSFUSE: not needed */
      /*kmem_cache_set_move(znode_cache, zfs_znode_move);*/
}

void
zfs_znode_fini(void)
{
      /*
       * Cleanup vfs & vnode ops
       */
      /* ZFSFUSE: TODO */
      /* zfs_remove_op_tables(); */

      /*
       * Cleanup zcache
       */
      if (znode_cache)
            kmem_cache_destroy(znode_cache);
      znode_cache = NULL;
}

struct vnodeops *zfs_dvnodeops;
struct vnodeops *zfs_fvnodeops;
struct vnodeops *zfs_symvnodeops;
struct vnodeops *zfs_xdvnodeops;
struct vnodeops *zfs_evnodeops;
struct vnodeops *zfs_sharevnodeops;

void
zfs_remove_op_tables()
{
      /*
       * Remove vfs ops
       */
      ASSERT(zfsfstype);
      (void) vfs_freevfsops_by_type(zfsfstype);
      zfsfstype = 0;

      /*
       * Remove vnode ops
       */
      if (zfs_dvnodeops)
            vn_freevnodeops(zfs_dvnodeops);
      if (zfs_fvnodeops)
            vn_freevnodeops(zfs_fvnodeops);
      if (zfs_symvnodeops)
            vn_freevnodeops(zfs_symvnodeops);
      if (zfs_xdvnodeops)
            vn_freevnodeops(zfs_xdvnodeops);
      if (zfs_evnodeops)
            vn_freevnodeops(zfs_evnodeops);
      if (zfs_sharevnodeops)
            vn_freevnodeops(zfs_sharevnodeops);

      zfs_dvnodeops = NULL;
      zfs_fvnodeops = NULL;
      zfs_symvnodeops = NULL;
      zfs_xdvnodeops = NULL;
      zfs_evnodeops = NULL;
      zfs_sharevnodeops = NULL;
}

extern const fs_operation_def_t zfs_dvnodeops_template[];
extern const fs_operation_def_t zfs_fvnodeops_template[];
extern const fs_operation_def_t zfs_xdvnodeops_template[];
extern const fs_operation_def_t zfs_symvnodeops_template[];
extern const fs_operation_def_t zfs_evnodeops_template[];
extern const fs_operation_def_t zfs_sharevnodeops_template[];

int
zfs_create_op_tables()
{
      int error;

      /*
       * zfs_dvnodeops can be set if mod_remove() calls mod_installfs()
       * due to a failure to remove the the 2nd modlinkage (zfs_modldrv).
       * In this case we just return as the ops vectors are already set up.
       */
      if (zfs_dvnodeops)
            return (0);

      error = vn_make_ops(MNTTYPE_ZFS, zfs_dvnodeops_template,
          &zfs_dvnodeops);
      if (error)
            return (error);

      error = vn_make_ops(MNTTYPE_ZFS, zfs_fvnodeops_template,
          &zfs_fvnodeops);
      if (error)
            return (error);

      error = vn_make_ops(MNTTYPE_ZFS, zfs_symvnodeops_template,
          &zfs_symvnodeops);
      if (error)
            return (error);

      error = vn_make_ops(MNTTYPE_ZFS, zfs_xdvnodeops_template,
          &zfs_xdvnodeops);
      if (error)
            return (error);

      error = vn_make_ops(MNTTYPE_ZFS, zfs_evnodeops_template,
          &zfs_evnodeops);
      if (error)
            return (error);

      error = vn_make_ops(MNTTYPE_ZFS, zfs_sharevnodeops_template,
          &zfs_sharevnodeops);

      return (error);
}

int
zfs_create_share_dir(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
{
      zfs_acl_ids_t acl_ids;
      vattr_t vattr;
      znode_t *sharezp;
      vnode_t *vp;
      znode_t *zp;
      int error;

      vattr.va_mask = AT_MODE|AT_UID|AT_GID|AT_TYPE;
      vattr.va_type = VDIR;
      vattr.va_mode = S_IFDIR|0555;
      vattr.va_uid = crgetuid(kcred);
      vattr.va_gid = crgetgid(kcred);

      sharezp = kmem_cache_alloc(znode_cache, KM_SLEEP);
      sharezp->z_unlinked = 0;
      sharezp->z_atime_dirty = 0;
      sharezp->z_zfsvfs = zfsvfs;

      vp = ZTOV(sharezp);
      vn_reinit(vp);
      vp->v_type = VDIR;

      VERIFY(0 == zfs_acl_ids_create(sharezp, IS_ROOT_NODE, &vattr,
          kcred, NULL, &acl_ids));
      zfs_mknode(sharezp, &vattr, tx, kcred, IS_ROOT_NODE,
          &zp, 0, &acl_ids);
      ASSERT3P(zp, ==, sharezp);
      ASSERT(!vn_in_dnlc(ZTOV(sharezp))); /* not valid to move */
      POINTER_INVALIDATE(&sharezp->z_zfsvfs);
      error = zap_add(zfsvfs->z_os, MASTER_NODE_OBJ,
          ZFS_SHARES_DIR, 8, 1, &sharezp->z_id, tx);
      zfsvfs->z_shares_dir = sharezp->z_id;

      zfs_acl_ids_free(&acl_ids);
      ZTOV(sharezp)->v_count = 0;
      dmu_buf_rele(sharezp->z_dbuf, NULL);
      sharezp->z_dbuf = NULL;
      kmem_cache_free(znode_cache, sharezp);

      return (error);
}

/*
 * define a couple of values we need available
 * for both 64 and 32 bit environments.
 */
#ifndef NBITSMINOR64
#define     NBITSMINOR64      32
#endif
#ifndef MAXMAJ64
#define     MAXMAJ64    0xffffffffUL
#endif
#ifndef     MAXMIN64
#define     MAXMIN64    0xffffffffUL
#endif

/*
 * Create special expldev for ZFS private use.
 * Can't use standard expldev since it doesn't do
 * what we want.  The standard expldev() takes a
 * dev32_t in LP64 and expands it to a long dev_t.
 * We need an interface that takes a dev32_t in ILP32
 * and expands it to a long dev_t.
 */
static uint64_t
zfs_expldev(dev_t dev)
{
/* ZFSFUSE: dev_t is always 64 bits in linux */
#if 0
      major_t major = (major_t)dev >> NBITSMINOR32 & MAXMAJ32;
      return (((uint64_t)major << NBITSMINOR64) |
          ((minor_t)dev & MAXMIN32));
#else
      return (dev);
#endif
}

/*
 * Special cmpldev for ZFS private use.
 * Can't use standard cmpldev since it takes
 * a long dev_t and compresses it to dev32_t in
 * LP64.  We need to do a compaction of a long dev_t
 * to a dev32_t in ILP32.
 */
dev_t
zfs_cmpldev(uint64_t dev)
{
/* ZFSFUSE: dev_t is always 64 bits in linux */
#if 0
      minor_t minor = (minor_t)dev & MAXMIN64;
      major_t major = (major_t)(dev >> NBITSMINOR64) & MAXMAJ64;

      if (major > MAXMAJ32 || minor > MAXMIN32)
            return (NODEV32);

      return (((dev32_t)major << NBITSMINOR32) | minor);
#else
      return (dev);
#endif
}

static void
zfs_znode_dmu_init(zfsvfs_t *zfsvfs, znode_t *zp, dmu_buf_t *db)
{
      znode_t           *nzp;

      /* ZFSFUSE */
      /* ASSERT(!POINTER_IS_VALID(zp->z_zfsvfs) || (zfsvfs == zp->z_zfsvfs)); */
      ASSERT(MUTEX_HELD(ZFS_OBJ_MUTEX(zfsvfs, zp->z_id)));

      mutex_enter(&zp->z_lock);

      ASSERT(zp->z_dbuf == NULL);
      zp->z_dbuf = db;
      nzp = dmu_buf_set_user_ie(db, zp, &zp->z_phys, znode_evict_error);

      /*
       * there should be no
       * concurrent zgets on this object.
       */
      if (nzp != NULL)
            panic("existing znode %p for dbuf %p", (void *)nzp, (void *)db);

      /*
       * Slap on VROOT if we are the root znode
       */
      if (zp->z_id == zfsvfs->z_root)
            ZTOV(zp)->v_flag |= VROOT;

      mutex_exit(&zp->z_lock);
      vn_exists(ZTOV(zp));
}

void
zfs_znode_dmu_fini(znode_t *zp)
{
      dmu_buf_t *db = zp->z_dbuf;
      ASSERT(MUTEX_HELD(ZFS_OBJ_MUTEX(zp->z_zfsvfs, zp->z_id)) ||
          zp->z_unlinked ||
          RW_WRITE_HELD(&zp->z_zfsvfs->z_teardown_inactive_lock));
      ASSERT(zp->z_dbuf != NULL);
      zp->z_dbuf = NULL;
      VERIFY(zp == dmu_buf_update_user(db, zp, NULL, NULL, NULL));
      dmu_buf_rele(db, NULL);
}

/*
 * Construct a new znode/vnode and intialize.
 *
 * This does not do a call to dmu_set_user() that is
 * up to the caller to do, in case you don't want to
 * return the znode
 */
static znode_t *
zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz)
{
      znode_t     *zp;
      vnode_t *vp;

      zp = kmem_cache_alloc(znode_cache, KM_SLEEP);

      ASSERT(zp->z_dirlocks == NULL);
      ASSERT(zp->z_dbuf == NULL);
      /* ZFSFUSE */
      /* ASSERT(!POINTER_IS_VALID(zp->z_zfsvfs)); */

      /*
       * Defer setting z_zfsvfs until the znode is ready to be a candidate for
       * the zfs_znode_move() callback.
       */
      zp->z_phys = NULL;
      zp->z_unlinked = 0;
      zp->z_atime_dirty = 0;
      zp->z_mapcnt = 0;
      zp->z_last_itx = 0;
      zp->z_id = db->db_object;
      zp->z_blksz = blksz;
      zp->z_seq = 0x7A4653;
      zp->z_sync_cnt = 0;

      vp = ZTOV(zp);
      vn_reinit(vp);

      zfs_znode_dmu_init(zfsvfs, zp, db);

      zp->z_gen = zp->z_phys->zp_gen;

      vp->v_vfsp = zfsvfs->z_parent->z_vfs;
      vp->v_type = IFTOVT((mode_t)zp->z_phys->zp_mode);

      switch (vp->v_type) {
      case VDIR:
            if (zp->z_phys->zp_flags & ZFS_XATTR) {
                  vn_setops(vp, zfs_xdvnodeops);
                  vp->v_flag |= V_XATTRDIR;
            } else {
                  vn_setops(vp, zfs_dvnodeops);
            }
            zp->z_zn_prefetch = B_TRUE; /* z_prefetch default is enabled */
            break;
      case VBLK:
      case VCHR:
            vp->v_rdev = zfs_cmpldev(zp->z_phys->zp_rdev);
            /*FALLTHROUGH*/
      case VFIFO:
      case VSOCK:
      case VDOOR:
            vn_setops(vp, zfs_fvnodeops);
            break;
      case VREG:
            vp->v_flag |= VMODSORT;
            if (zp->z_phys->zp_parent == zfsvfs->z_shares_dir)
                  vn_setops(vp, zfs_sharevnodeops);
            else
                  vn_setops(vp, zfs_fvnodeops);
            break;
      case VLNK:
            vn_setops(vp, zfs_symvnodeops);
            break;
      default:
            vn_setops(vp, zfs_evnodeops);
            break;
      }

      mutex_enter(&zfsvfs->z_znodes_lock);
      list_insert_tail(&zfsvfs->z_all_znodes, zp);
      membar_producer();
      /*
       * Everything else must be valid before assigning z_zfsvfs makes the
       * znode eligible for zfs_znode_move().
       */
      zp->z_zfsvfs = zfsvfs;
      mutex_exit(&zfsvfs->z_znodes_lock);

      VFS_HOLD(zfsvfs->z_vfs);
      return (zp);
}

/*
 * Create a new DMU object to hold a zfs znode.
 *
 *    IN:   dzp   - parent directory for new znode
 *          vap   - file attributes for new znode
 *          tx    - dmu transaction id for zap operations
 *          cr    - credentials of caller
 *          flag  - flags:
 *                  IS_ROOT_NODE    - new object will be root
 *                  IS_XATTR  - new object is an attribute
 *                  IS_REPLAY - intent log replay
 *          bonuslen - length of bonus buffer
 *          setaclp  - File/Dir initial ACL
 *          fuidp  - Tracks fuid allocation.
 *
 *    OUT:  zpp   - allocated znode
 *
 */
void
zfs_mknode(znode_t *dzp, vattr_t *vap, dmu_tx_t *tx, cred_t *cr,
    uint_t flag, znode_t **zpp, int bonuslen, zfs_acl_ids_t *acl_ids)
{
      dmu_buf_t   *db;
      znode_phys_t      *pzp;
      zfsvfs_t    *zfsvfs = dzp->z_zfsvfs;
      timestruc_t now;
      uint64_t    gen, obj;
      int         err;

      ASSERT(vap && (vap->va_mask & (AT_TYPE|AT_MODE)) == (AT_TYPE|AT_MODE));

      if (zfsvfs->z_replay) {
            obj = vap->va_nodeid;
            flag |= IS_REPLAY;
            now = vap->va_ctime;          /* see zfs_replay_create() */
            gen = vap->va_nblocks;        /* ditto */
      } else {
            obj = 0;
            gethrestime(&now);
            gen = dmu_tx_get_txg(tx);
      }

      /*
       * Create a new DMU object.
       */
      /*
       * There's currently no mechanism for pre-reading the blocks that will
       * be to needed allocate a new object, so we accept the small chance
       * that there will be an i/o error and we will fail one of the
       * assertions below.
       */
      if (vap->va_type == VDIR) {
            if (flag & IS_REPLAY) {
                  err = zap_create_claim_norm(zfsvfs->z_os, obj,
                      zfsvfs->z_norm, DMU_OT_DIRECTORY_CONTENTS,
                      DMU_OT_ZNODE, sizeof (znode_phys_t) + bonuslen, tx);
                  ASSERT3U(err, ==, 0);
            } else {
                  obj = zap_create_norm(zfsvfs->z_os,
                      zfsvfs->z_norm, DMU_OT_DIRECTORY_CONTENTS,
                      DMU_OT_ZNODE, sizeof (znode_phys_t) + bonuslen, tx);
            }
      } else {
            if (flag & IS_REPLAY) {
                  err = dmu_object_claim(zfsvfs->z_os, obj,
                      DMU_OT_PLAIN_FILE_CONTENTS, 0,
                      DMU_OT_ZNODE, sizeof (znode_phys_t) + bonuslen, tx);
                  ASSERT3U(err, ==, 0);
            } else {
                  obj = dmu_object_alloc(zfsvfs->z_os,
                      DMU_OT_PLAIN_FILE_CONTENTS, 0,
                      DMU_OT_ZNODE, sizeof (znode_phys_t) + bonuslen, tx);
            }
      }
      VERIFY(0 == dmu_bonus_hold(zfsvfs->z_os, obj, NULL, &db));
      dmu_buf_will_dirty(db, tx);

      /*
       * Initialize the znode physical data to zero.
       */
      ASSERT(db->db_size >= sizeof (znode_phys_t));
      bzero(db->db_data, db->db_size);
      pzp = db->db_data;

      /*
       * If this is the root, fix up the half-initialized parent pointer
       * to reference the just-allocated physical data area.
       */
      if (flag & IS_ROOT_NODE) {
            dzp->z_dbuf = db;
            dzp->z_phys = pzp;
            dzp->z_id = obj;
      }

      /*
       * If parent is an xattr, so am I.
       */
      if (dzp->z_phys->zp_flags & ZFS_XATTR)
            flag |= IS_XATTR;

      if (vap->va_type == VBLK || vap->va_type == VCHR) {
            pzp->zp_rdev = zfs_expldev(vap->va_rdev);
      }

      if (zfsvfs->z_use_fuids)
            pzp->zp_flags = ZFS_ARCHIVE | ZFS_AV_MODIFIED;

      if (vap->va_type == VDIR) {
            pzp->zp_size = 2;       /* contents ("." and "..") */
            pzp->zp_links = (flag & (IS_ROOT_NODE | IS_XATTR)) ? 2 : 1;
      }

      pzp->zp_parent = dzp->z_id;
      if (flag & IS_XATTR)
            pzp->zp_flags |= ZFS_XATTR;

      pzp->zp_gen = gen;

      ZFS_TIME_ENCODE(&now, pzp->zp_crtime);
      ZFS_TIME_ENCODE(&now, pzp->zp_ctime);

      if (vap->va_mask & AT_ATIME) {
            ZFS_TIME_ENCODE(&vap->va_atime, pzp->zp_atime);
      } else {
            ZFS_TIME_ENCODE(&now, pzp->zp_atime);
      }

      if (vap->va_mask & AT_MTIME) {
            ZFS_TIME_ENCODE(&vap->va_mtime, pzp->zp_mtime);
      } else {
            ZFS_TIME_ENCODE(&now, pzp->zp_mtime);
      }

      pzp->zp_mode = MAKEIMODE(vap->va_type, vap->va_mode);
      if (!(flag & IS_ROOT_NODE)) {
            ZFS_OBJ_HOLD_ENTER(zfsvfs, obj);
            *zpp = zfs_znode_alloc(zfsvfs, db, 0);
            ZFS_OBJ_HOLD_EXIT(zfsvfs, obj);
      } else {
            /*
             * If we are creating the root node, the "parent" we
             * passed in is the znode for the root.
             */
            *zpp = dzp;
      }
      pzp->zp_uid = acl_ids->z_fuid;
      pzp->zp_gid = acl_ids->z_fgid;
      pzp->zp_mode = acl_ids->z_mode;
      VERIFY(0 == zfs_aclset_common(*zpp, acl_ids->z_aclp, cr, tx));
      if (vap->va_mask & AT_XVATTR)
            zfs_xvattr_set(*zpp, (xvattr_t *)vap);
}

void
zfs_xvattr_set(znode_t *zp, xvattr_t *xvap)
{
      /* ZFS-FUSE: not implemented */
      abort();
#if 0
      xoptattr_t *xoap;

      xoap = xva_getxoptattr(xvap);
      ASSERT(xoap);

      if (XVA_ISSET_REQ(xvap, XAT_CREATETIME)) {
            ZFS_TIME_ENCODE(&xoap->xoa_createtime, zp->z_phys->zp_crtime);
            XVA_SET_RTN(xvap, XAT_CREATETIME);
      }
      if (XVA_ISSET_REQ(xvap, XAT_READONLY)) {
            ZFS_ATTR_SET(zp, ZFS_READONLY, xoap->xoa_readonly);
            XVA_SET_RTN(xvap, XAT_READONLY);
      }
      if (XVA_ISSET_REQ(xvap, XAT_HIDDEN)) {
            ZFS_ATTR_SET(zp, ZFS_HIDDEN, xoap->xoa_hidden);
            XVA_SET_RTN(xvap, XAT_HIDDEN);
      }
      if (XVA_ISSET_REQ(xvap, XAT_SYSTEM)) {
            ZFS_ATTR_SET(zp, ZFS_SYSTEM, xoap->xoa_system);
            XVA_SET_RTN(xvap, XAT_SYSTEM);
      }
      if (XVA_ISSET_REQ(xvap, XAT_ARCHIVE)) {
            ZFS_ATTR_SET(zp, ZFS_ARCHIVE, xoap->xoa_archive);
            XVA_SET_RTN(xvap, XAT_ARCHIVE);
      }
      if (XVA_ISSET_REQ(xvap, XAT_IMMUTABLE)) {
            ZFS_ATTR_SET(zp, ZFS_IMMUTABLE, xoap->xoa_immutable);
            XVA_SET_RTN(xvap, XAT_IMMUTABLE);
      }
      if (XVA_ISSET_REQ(xvap, XAT_NOUNLINK)) {
            ZFS_ATTR_SET(zp, ZFS_NOUNLINK, xoap->xoa_nounlink);
            XVA_SET_RTN(xvap, XAT_NOUNLINK);
      }
      if (XVA_ISSET_REQ(xvap, XAT_APPENDONLY)) {
            ZFS_ATTR_SET(zp, ZFS_APPENDONLY, xoap->xoa_appendonly);
            XVA_SET_RTN(xvap, XAT_APPENDONLY);
      }
      if (XVA_ISSET_REQ(xvap, XAT_NODUMP)) {
            ZFS_ATTR_SET(zp, ZFS_NODUMP, xoap->xoa_nodump);
            XVA_SET_RTN(xvap, XAT_NODUMP);
      }
      if (XVA_ISSET_REQ(xvap, XAT_OPAQUE)) {
            ZFS_ATTR_SET(zp, ZFS_OPAQUE, xoap->xoa_opaque);
            XVA_SET_RTN(xvap, XAT_OPAQUE);
      }
      if (XVA_ISSET_REQ(xvap, XAT_AV_QUARANTINED)) {
            ZFS_ATTR_SET(zp, ZFS_AV_QUARANTINED,
                xoap->xoa_av_quarantined);
            XVA_SET_RTN(xvap, XAT_AV_QUARANTINED);
      }
      if (XVA_ISSET_REQ(xvap, XAT_AV_MODIFIED)) {
            ZFS_ATTR_SET(zp, ZFS_AV_MODIFIED, xoap->xoa_av_modified);
            XVA_SET_RTN(xvap, XAT_AV_MODIFIED);
      }
      if (XVA_ISSET_REQ(xvap, XAT_AV_SCANSTAMP)) {
            (void) memcpy(zp->z_phys + 1, xoap->xoa_av_scanstamp,
                sizeof (xoap->xoa_av_scanstamp));
            zp->z_phys->zp_flags |= ZFS_BONUS_SCANSTAMP;
            XVA_SET_RTN(xvap, XAT_AV_SCANSTAMP);
      }
#endif
}

int
zfs_zget(zfsvfs_t *zfsvfs, uint64_t obj_num, znode_t **zpp, boolean_t zget_unlinked)
{
      dmu_object_info_t doi;
      dmu_buf_t   *db;
      znode_t           *zp;
      int err;

      *zpp = NULL;

      ZFS_OBJ_HOLD_ENTER(zfsvfs, obj_num);

      err = dmu_bonus_hold(zfsvfs->z_os, obj_num, NULL, &db);
      if (err) {
            ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
            return (err);
      }

      dmu_object_info_from_db(db, &doi);
      if (doi.doi_bonus_type != DMU_OT_ZNODE ||
          doi.doi_bonus_size < sizeof (znode_phys_t)) {
            dmu_buf_rele(db, NULL);
            ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
            return (EINVAL);
      }

      zp = dmu_buf_get_user(db);
      if (zp != NULL) {
            mutex_enter(&zp->z_lock);

            /*
             * Since we do immediate eviction of the z_dbuf, we
             * should never find a dbuf with a znode that doesn't
             * know about the dbuf.
             */
            ASSERT3P(zp->z_dbuf, ==, db);
            ASSERT3U(zp->z_id, ==, obj_num);
            if (zp->z_unlinked && !zget_unlinked) {
                  err = ENOENT;
            } else {
                  VN_HOLD(ZTOV(zp));
                  *zpp = zp;
                  err = 0;
            }
            dmu_buf_rele(db, NULL);
            mutex_exit(&zp->z_lock);
            ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
            return (err);
      }

      /*
       * Not found create new znode/vnode
       */
      zp = zfs_znode_alloc(zfsvfs, db, doi.doi_data_block_size);
      ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
      *zpp = zp;
      return (0);
}

int
zfs_rezget(znode_t *zp)
{
      zfsvfs_t *zfsvfs = zp->z_zfsvfs;
      dmu_object_info_t doi;
      dmu_buf_t *db;
      uint64_t obj_num = zp->z_id;
      int err;

      ZFS_OBJ_HOLD_ENTER(zfsvfs, obj_num);

      err = dmu_bonus_hold(zfsvfs->z_os, obj_num, NULL, &db);
      if (err) {
            ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
            return (err);
      }

      dmu_object_info_from_db(db, &doi);
      if (doi.doi_bonus_type != DMU_OT_ZNODE ||
          doi.doi_bonus_size < sizeof (znode_phys_t)) {
            dmu_buf_rele(db, NULL);
            ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
            return (EINVAL);
      }

      if (((znode_phys_t *)db->db_data)->zp_gen != zp->z_gen) {
            dmu_buf_rele(db, NULL);
            ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
            return (EIO);
      }

      zfs_znode_dmu_init(zfsvfs, zp, db);
      zp->z_unlinked = (zp->z_phys->zp_links == 0);
      zp->z_blksz = doi.doi_data_block_size;

      ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);

      return (0);
}

void
zfs_znode_delete(znode_t *zp, dmu_tx_t *tx)
{
      zfsvfs_t *zfsvfs = zp->z_zfsvfs;
      objset_t *os = zfsvfs->z_os;
      uint64_t obj = zp->z_id;
      uint64_t acl_obj = zp->z_phys->zp_acl.z_acl_extern_obj;

      ZFS_OBJ_HOLD_ENTER(zfsvfs, obj);
      if (acl_obj)
            VERIFY(0 == dmu_object_free(os, acl_obj, tx));
      VERIFY(0 == dmu_object_free(os, obj, tx));
      zfs_znode_dmu_fini(zp);
      ZFS_OBJ_HOLD_EXIT(zfsvfs, obj);
      zfs_znode_free(zp);
}

void
zfs_zinactive(znode_t *zp)
{
      vnode_t     *vp = ZTOV(zp);
      zfsvfs_t *zfsvfs = zp->z_zfsvfs;
      uint64_t z_id = zp->z_id;

      ASSERT(zp->z_dbuf && zp->z_phys);

      /*
       * Don't allow a zfs_zget() while were trying to release this znode
       */
      ZFS_OBJ_HOLD_ENTER(zfsvfs, z_id);

      mutex_enter(&zp->z_lock);
      mutex_enter(&vp->v_lock);
      vp->v_count--;
      if (vp->v_count > 0 || vn_has_cached_data(vp)) {
            /*
             * If the hold count is greater than zero, somebody has
             * obtained a new reference on this znode while we were
             * processing it here, so we are done.  If we still have
             * mapped pages then we are also done, since we don't
             * want to inactivate the znode until the pages get pushed.
             *
             * XXX - if vn_has_cached_data(vp) is true, but count == 0,
             * this seems like it would leave the znode hanging with
             * no chance to go inactive...
             */
            mutex_exit(&vp->v_lock);
            mutex_exit(&zp->z_lock);
            ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
            return;
      }
      mutex_exit(&vp->v_lock);

      /*
       * If this was the last reference to a file with no links,
       * remove the file from the file system.
       */
      if (zp->z_unlinked) {
            mutex_exit(&zp->z_lock);
            ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
            zfs_rmnode(zp);
            return;
      }
      mutex_exit(&zp->z_lock);
      zfs_znode_dmu_fini(zp);
      ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
      zfs_znode_free(zp);
}

void
zfs_znode_free(znode_t *zp)
{
      zfsvfs_t *zfsvfs = zp->z_zfsvfs;

      vn_invalid(ZTOV(zp));

      ASSERT(ZTOV(zp)->v_count == 0);

      mutex_enter(&zfsvfs->z_znodes_lock);
      POINTER_INVALIDATE(&zp->z_zfsvfs);
      list_remove(&zfsvfs->z_all_znodes, zp);
      mutex_exit(&zfsvfs->z_znodes_lock);

      kmem_cache_free(znode_cache, zp);

      VFS_RELE(zfsvfs->z_vfs);
}

void
zfs_time_stamper_locked(znode_t *zp, uint_t flag, dmu_tx_t *tx)
{
      timestruc_t now;

      ASSERT(MUTEX_HELD(&zp->z_lock));

      gethrestime(&now);

      if (tx) {
            dmu_buf_will_dirty(zp->z_dbuf, tx);
            zp->z_atime_dirty = 0;
            zp->z_seq++;
      } else {
            zp->z_atime_dirty = 1;
      }

      if (flag & AT_ATIME)
            ZFS_TIME_ENCODE(&now, zp->z_phys->zp_atime);

      if (flag & AT_MTIME) {
            ZFS_TIME_ENCODE(&now, zp->z_phys->zp_mtime);
            if (zp->z_zfsvfs->z_use_fuids)
                  zp->z_phys->zp_flags |= (ZFS_ARCHIVE | ZFS_AV_MODIFIED);
      }

      if (flag & AT_CTIME) {
            ZFS_TIME_ENCODE(&now, zp->z_phys->zp_ctime);
            if (zp->z_zfsvfs->z_use_fuids)
                  zp->z_phys->zp_flags |= ZFS_ARCHIVE;
      }
}

/*
 * Update the requested znode timestamps with the current time.
 * If we are in a transaction, then go ahead and mark the znode
 * dirty in the transaction so the timestamps will go to disk.
 * Otherwise, we will get pushed next time the znode is updated
 * in a transaction, or when this znode eventually goes inactive.
 *
 * Why is this OK?
 *  1 - Only the ACCESS time is ever updated outside of a transaction.
 *  2 - Multiple consecutive updates will be collapsed into a single
 *    znode update by the transaction grouping semantics of the DMU.
 */
void
zfs_time_stamper(znode_t *zp, uint_t flag, dmu_tx_t *tx)
{
      mutex_enter(&zp->z_lock);
      zfs_time_stamper_locked(zp, flag, tx);
      mutex_exit(&zp->z_lock);
}

/*
 * Grow the block size for a file.
 *
 *    IN:   zp    - znode of file to free data in.
 *          size  - requested block size
 *          tx    - open transaction.
 *
 * NOTE: this function assumes that the znode is write locked.
 */
void
zfs_grow_blocksize(znode_t *zp, uint64_t size, dmu_tx_t *tx)
{
      int         error;
      u_longlong_t      dummy;

      if (size <= zp->z_blksz)
            return;
      /*
       * If the file size is already greater than the current blocksize,
       * we will not grow.  If there is more than one block in a file,
       * the blocksize cannot change.
       */
      if (zp->z_blksz && zp->z_phys->zp_size > zp->z_blksz)
            return;

      error = dmu_object_set_blocksize(zp->z_zfsvfs->z_os, zp->z_id,
          size, 0, tx);
      if (error == ENOTSUP)
            return;
      ASSERT3U(error, ==, 0);

      /* What blocksize did we actually get? */
      dmu_object_size_from_db(zp->z_dbuf, &zp->z_blksz, &dummy);
}

/*
 * This is a dummy interface used when pvn_vplist_dirty() should *not*
 * be calling back into the fs for a putpage().  E.g.: when truncating
 * a file, the pages being "thrown away* don't need to be written out.
 */
/* ARGSUSED */
#if 0
static int
zfs_no_putpage(vnode_t *vp, page_t *pp, u_offset_t *offp, size_t *lenp,
    int flags, cred_t *cr)
{
      ASSERT(0);
      return (0);
}
#endif

/*
 * Increase the file length
 *
 *    IN:   zp    - znode of file to free data in.
 *          end   - new end-of-file
 *
 *    RETURN:     0 if success
 *          error code if failure
 */
static int
zfs_extend(znode_t *zp, uint64_t end)
{
      zfsvfs_t *zfsvfs = zp->z_zfsvfs;
      dmu_tx_t *tx;
      rl_t *rl;
      uint64_t newblksz;
      int error;

      /*
       * We will change zp_size, lock the whole file.
       */
      rl = zfs_range_lock(zp, 0, UINT64_MAX, RL_WRITER);

      /*
       * Nothing to do if file already at desired length.
       */
      if (end <= zp->z_phys->zp_size) {
            zfs_range_unlock(rl);
            return (0);
      }
top:
      tx = dmu_tx_create(zfsvfs->z_os);
      dmu_tx_hold_bonus(tx, zp->z_id);
      if (end > zp->z_blksz &&
          (!ISP2(zp->z_blksz) || zp->z_blksz < zfsvfs->z_max_blksz)) {
            /*
             * We are growing the file past the current block size.
             */
            if (zp->z_blksz > zp->z_zfsvfs->z_max_blksz) {
                  ASSERT(!ISP2(zp->z_blksz));
                  newblksz = MIN(end, SPA_MAXBLOCKSIZE);
            } else {
                  newblksz = MIN(end, zp->z_zfsvfs->z_max_blksz);
            }
            dmu_tx_hold_write(tx, zp->z_id, 0, newblksz);
      } else {
            newblksz = 0;
      }

      error = dmu_tx_assign(tx, TXG_NOWAIT);
      if (error) {
            if (error == ERESTART) {
                  dmu_tx_wait(tx);
                  dmu_tx_abort(tx);
                  goto top;
            }
            dmu_tx_abort(tx);
            zfs_range_unlock(rl);
            return (error);
      }
      dmu_buf_will_dirty(zp->z_dbuf, tx);

      if (newblksz)
            zfs_grow_blocksize(zp, newblksz, tx);

      zp->z_phys->zp_size = end;

      zfs_range_unlock(rl);

      dmu_tx_commit(tx);

      return (0);
}

/*
 * Free space in a file.
 *
 *    IN:   zp    - znode of file to free data in.
 *          off   - start of section to free.
 *          len   - length of section to free.
 *
 *    RETURN:     0 if success
 *          error code if failure
 */
static int
zfs_free_range(znode_t *zp, uint64_t off, uint64_t len)
{
      zfsvfs_t *zfsvfs = zp->z_zfsvfs;
      rl_t *rl;
      int error;

      /*
       * Lock the range being freed.
       */
      rl = zfs_range_lock(zp, off, len, RL_WRITER);

      /*
       * Nothing to do if file already at desired length.
       */
      if (off >= zp->z_phys->zp_size) {
            zfs_range_unlock(rl);
            return (0);
      }

      if (off + len > zp->z_phys->zp_size)
            len = zp->z_phys->zp_size - off;

      error = dmu_free_long_range(zfsvfs->z_os, zp->z_id, off, len);

      zfs_range_unlock(rl);

      return (error);
}

/*
 * Truncate a file
 *
 *    IN:   zp    - znode of file to free data in.
 *          end   - new end-of-file.
 *
 *    RETURN:     0 if success
 *          error code if failure
 */
static int
zfs_trunc(znode_t *zp, uint64_t end)
{
      zfsvfs_t *zfsvfs = zp->z_zfsvfs;
      vnode_t *vp = ZTOV(zp);
      dmu_tx_t *tx;
      rl_t *rl;
      int error;

      /*
       * We will change zp_size, lock the whole file.
       */
      rl = zfs_range_lock(zp, 0, UINT64_MAX, RL_WRITER);

      /*
       * Nothing to do if file already at desired length.
       */
      if (end >= zp->z_phys->zp_size) {
            zfs_range_unlock(rl);
            return (0);
      }

      error = dmu_free_long_range(zfsvfs->z_os, zp->z_id, end,  -1);
      if (error) {
            zfs_range_unlock(rl);
            return (error);
      }
top:
      tx = dmu_tx_create(zfsvfs->z_os);
      dmu_tx_hold_bonus(tx, zp->z_id);
      error = dmu_tx_assign(tx, TXG_NOWAIT);
      if (error) {
            if (error == ERESTART) {
                  dmu_tx_wait(tx);
                  dmu_tx_abort(tx);
                  goto top;
            }
            dmu_tx_abort(tx);
            zfs_range_unlock(rl);
            return (error);
      }
      dmu_buf_will_dirty(zp->z_dbuf, tx);

      zp->z_phys->zp_size = end;

      dmu_tx_commit(tx);

      /*
       * Clear any mapped pages in the truncated region.  This has to
       * happen outside of the transaction to avoid the possibility of
       * a deadlock with someone trying to push a page that we are
       * about to invalidate.
       */
      if (vn_has_cached_data(vp)) {
            /* ZFSFUSE: not implemented */
            abort();
#if 0
            page_t *pp;
            uint64_t start = end & PAGEMASK;
            int poff = end & PAGEOFFSET;

            if (poff != 0 && (pp = page_lookup(vp, start, SE_SHARED))) {
                  /*
                   * We need to zero a partial page.
                   */
                  pagezero(pp, poff, PAGESIZE - poff);
                  start += PAGESIZE;
                  page_unlock(pp);
            }
            error = pvn_vplist_dirty(vp, start, zfs_no_putpage,
                B_INVAL | B_TRUNC, NULL);
            ASSERT(error == 0);
#endif
      }

      zfs_range_unlock(rl);

      return (0);
}

/*
 * Free space in a file
 *
 *    IN:   zp    - znode of file to free data in.
 *          off   - start of range
 *          len   - end of range (0 => EOF)
 *          flag  - current file open mode flags.
 *          log   - TRUE if this action should be logged
 *
 *    RETURN:     0 if success
 *          error code if failure
 */
int
zfs_freesp(znode_t *zp, uint64_t off, uint64_t len, int flag, boolean_t log)
{
      vnode_t *vp = ZTOV(zp);
      dmu_tx_t *tx;
      zfsvfs_t *zfsvfs = zp->z_zfsvfs;
      zilog_t *zilog = zfsvfs->z_log;
      int error;

      if (off > zp->z_phys->zp_size) {
            error =  zfs_extend(zp, off+len);
            if (error == 0 && log)
                  goto log;
            else
                  return (error);
      }

      /*
       * Check for any locks in the region to be freed.
       */
      if (MANDLOCK(vp, (mode_t)zp->z_phys->zp_mode)) {
            uint64_t length = (len ? len : zp->z_phys->zp_size - off);
            if (error = chklock(vp, FWRITE, off, length, flag, NULL))
                  return (error);
      }

      if (len == 0) {
            error = zfs_trunc(zp, off);
      } else {
            if ((error = zfs_free_range(zp, off, len)) == 0 &&
                off + len > zp->z_phys->zp_size)
                  error = zfs_extend(zp, off+len);
      }
      if (error || !log)
            return (error);
log:
      tx = dmu_tx_create(zfsvfs->z_os);
      dmu_tx_hold_bonus(tx, zp->z_id);
      error = dmu_tx_assign(tx, TXG_NOWAIT);
      if (error) {
            if (error == ERESTART) {
                  dmu_tx_wait(tx);
                  dmu_tx_abort(tx);
                  goto log;
            }
            dmu_tx_abort(tx);
            return (error);
      }

      zfs_time_stamper(zp, CONTENT_MODIFIED, tx);
      zfs_log_truncate(zilog, tx, TX_TRUNCATE, zp, off, len);

      dmu_tx_commit(tx);
      return (0);
}

void
zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t *zplprops, dmu_tx_t *tx)
{
      zfsvfs_t    zfsvfs;
      uint64_t    moid, obj, version;
      uint64_t    sense = ZFS_CASE_SENSITIVE;
      uint64_t    norm = 0;
      nvpair_t    *elem;
      int         error;
      znode_t           *rootzp = NULL;
      vnode_t           *vp;
      vattr_t           vattr;
      znode_t           *zp;
      zfs_acl_ids_t     acl_ids;

      /*
       * First attempt to create master node.
       */
      /*
       * In an empty objset, there are no blocks to read and thus
       * there can be no i/o errors (which we assert below).
       */
      moid = MASTER_NODE_OBJ;
      error = zap_create_claim(os, moid, DMU_OT_MASTER_NODE,
          DMU_OT_NONE, 0, tx);
      ASSERT(error == 0);

      /*
       * Set starting attributes.
       */
      if (spa_version(dmu_objset_spa(os)) >= SPA_VERSION_USERSPACE)
            version = ZPL_VERSION;
      else if (spa_version(dmu_objset_spa(os)) >= SPA_VERSION_FUID)
            version = ZPL_VERSION_USERSPACE - 1;
      else
            version = ZPL_VERSION_FUID - 1;
      elem = NULL;
      while ((elem = nvlist_next_nvpair(zplprops, elem)) != NULL) {
            /* For the moment we expect all zpl props to be uint64_ts */
            uint64_t val;
            char *name;

            ASSERT(nvpair_type(elem) == DATA_TYPE_UINT64);
            VERIFY(nvpair_value_uint64(elem, &val) == 0);
            name = nvpair_name(elem);
            if (strcmp(name, zfs_prop_to_name(ZFS_PROP_VERSION)) == 0) {
                  if (val < version)
                        version = val;
            } else {
                  error = zap_update(os, moid, name, 8, 1, &val, tx);
            }
            ASSERT(error == 0);
            if (strcmp(name, zfs_prop_to_name(ZFS_PROP_NORMALIZE)) == 0)
                  norm = val;
            else if (strcmp(name, zfs_prop_to_name(ZFS_PROP_CASE)) == 0)
                  sense = val;
      }
      ASSERT(version != 0);
      error = zap_update(os, moid, ZPL_VERSION_STR, 8, 1, &version, tx);

      /*
       * Create a delete queue.
       */
      obj = zap_create(os, DMU_OT_UNLINKED_SET, DMU_OT_NONE, 0, tx);

      error = zap_add(os, moid, ZFS_UNLINKED_SET, 8, 1, &obj, tx);
      ASSERT(error == 0);

      /*
       * Create root znode.  Create minimal znode/vnode/zfsvfs
       * to allow zfs_mknode to work.
       */
      vattr.va_mask = AT_MODE|AT_UID|AT_GID|AT_TYPE;
      vattr.va_type = VDIR;
      vattr.va_mode = S_IFDIR|0755;
      vattr.va_uid = crgetuid(cr);
      vattr.va_gid = crgetgid(cr);

      rootzp = kmem_cache_alloc(znode_cache, KM_SLEEP);
      rootzp->z_unlinked = 0;
      rootzp->z_atime_dirty = 0;

      vp = ZTOV(rootzp);
      vn_reinit(vp);
      vp->v_type = VDIR;

      bzero(&zfsvfs, sizeof (zfsvfs_t));

      zfsvfs.z_os = os;
      zfsvfs.z_parent = &zfsvfs;
      zfsvfs.z_version = version;
      zfsvfs.z_use_fuids = USE_FUIDS(version, os);
      zfsvfs.z_norm = norm;
      /*
       * Fold case on file systems that are always or sometimes case
       * insensitive.
       */
      if (sense == ZFS_CASE_INSENSITIVE || sense == ZFS_CASE_MIXED)
            zfsvfs.z_norm |= U8_TEXTPREP_TOUPPER;

      mutex_init(&zfsvfs.z_znodes_lock, NULL, MUTEX_DEFAULT, NULL);
      list_create(&zfsvfs.z_all_znodes, sizeof (znode_t),
          offsetof(znode_t, z_link_node));

      /* ZFSFUSE */
      /* ASSERT(!POINTER_IS_VALID(rootzp->z_zfsvfs)); */
      rootzp->z_zfsvfs = &zfsvfs;
      VERIFY(0 == zfs_acl_ids_create(rootzp, IS_ROOT_NODE, &vattr,
          cr, NULL, &acl_ids));
      zfs_mknode(rootzp, &vattr, tx, cr, IS_ROOT_NODE, &zp, 0, &acl_ids);
      ASSERT3P(zp, ==, rootzp);
      ASSERT(!vn_in_dnlc(ZTOV(rootzp))); /* not valid to move */
      error = zap_add(os, moid, ZFS_ROOT_OBJ, 8, 1, &rootzp->z_id, tx);
      ASSERT(error == 0);
      zfs_acl_ids_free(&acl_ids);
      POINTER_INVALIDATE(&rootzp->z_zfsvfs);

      ZTOV(rootzp)->v_count = 0;
      dmu_buf_rele(rootzp->z_dbuf, NULL);
      rootzp->z_dbuf = NULL;
      kmem_cache_free(znode_cache, rootzp);

      /*
       * Create shares directory
       */

      error = zfs_create_share_dir(&zfsvfs, tx);

      ASSERT(error == 0);
}

#endif /* _KERNEL */
/*
 * Given an object number, return its parent object number and whether
 * or not the object is an extended attribute directory.
 */
static int
zfs_obj_to_pobj(objset_t *osp, uint64_t obj, uint64_t *pobjp, int *is_xattrdir)
{
      dmu_buf_t *db;
      dmu_object_info_t doi;
      znode_phys_t *zp;
      int error;

      if ((error = dmu_bonus_hold(osp, obj, FTAG, &db)) != 0)
            return (error);

      dmu_object_info_from_db(db, &doi);
      if (doi.doi_bonus_type != DMU_OT_ZNODE ||
          doi.doi_bonus_size < sizeof (znode_phys_t)) {
            dmu_buf_rele(db, FTAG);
            return (EINVAL);
      }

      zp = db->db_data;
      *pobjp = zp->zp_parent;
      *is_xattrdir = ((zp->zp_flags & ZFS_XATTR) != 0) &&
          S_ISDIR(zp->zp_mode);
      dmu_buf_rele(db, FTAG);

      return (0);
}

int
zfs_obj_to_path(objset_t *osp, uint64_t obj, char *buf, int len)
{
      char *path = buf + len - 1;
      int error;

      *path = '\0';

      for (;;) {
            uint64_t pobj;
            char component[MAXNAMELEN + 2];
            size_t complen;
            int is_xattrdir;

            if ((error = zfs_obj_to_pobj(osp, obj, &pobj,
                &is_xattrdir)) != 0)
                  break;

            if (pobj == obj) {
                  if (path[0] != '/')
                        *--path = '/';
                  break;
            }

            component[0] = '/';
            if (is_xattrdir) {
                  (void) sprintf(component + 1, "<xattrdir>");
            } else {
                  error = zap_value_search(osp, pobj, obj,
                      ZFS_DIRENT_OBJ(-1ULL), component + 1);
                  if (error != 0)
                        break;
            }

            complen = strlen(component);
            path -= complen;
            ASSERT(path >= buf);
            bcopy(component, path, complen);
            obj = pobj;
      }

      if (error == 0)
            (void) memmove(buf, path, buf + len - path);
      return (error);
}

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