xref: /illumos-gate/usr/src/uts/common/fs/zfs/zfs_znode.c (revision a07094369b21309434206d9b3601d162693466fc)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <sys/types.h>
30 #include <sys/param.h>
31 #include <sys/time.h>
32 #include <sys/systm.h>
33 #include <sys/sysmacros.h>
34 #include <sys/resource.h>
35 #include <sys/mntent.h>
36 #include <sys/vfs.h>
37 #include <sys/vnode.h>
38 #include <sys/file.h>
39 #include <sys/kmem.h>
40 #include <sys/cmn_err.h>
41 #include <sys/errno.h>
42 #include <sys/unistd.h>
43 #include <sys/stat.h>
44 #include <sys/mode.h>
45 #include <sys/atomic.h>
46 #include <vm/pvn.h>
47 #include "fs/fs_subr.h"
48 #include <sys/zfs_dir.h>
49 #include <sys/zfs_acl.h>
50 #include <sys/zfs_ioctl.h>
51 #include <sys/zfs_znode.h>
52 #include <sys/zap.h>
53 #include <sys/dmu.h>
54 #include <sys/fs/zfs.h>
55 
56 struct kmem_cache *znode_cache = NULL;
57 
58 /*
59  * Note that znodes can be on one of 2 states:
60  *	ZCACHE_mru	- recently used, currently cached
61  *	ZCACHE_mfu	- frequently used, currently cached
62  * When there are no active references to the znode, they
63  * are linked onto one of the lists in zcache.  These are the
64  * only znodes that can be evicted.
65  */
66 
67 typedef struct zcache_state {
68 	list_t	list;	/* linked list of evictable znodes in state */
69 	uint64_t lcnt;	/* total number of znodes in the linked list */
70 	uint64_t cnt;	/* total number of all znodes in this state */
71 	uint64_t hits;
72 	kmutex_t mtx;
73 } zcache_state_t;
74 
75 /* The 2 states: */
76 static zcache_state_t ZCACHE_mru;
77 static zcache_state_t ZCACHE_mfu;
78 
79 static struct zcache {
80 	zcache_state_t	*mru;
81 	zcache_state_t	*mfu;
82 	uint64_t	p;		/* Target size of mru */
83 	uint64_t	c;		/* Target size of cache */
84 	uint64_t	c_max;		/* Maximum target cache size */
85 
86 	/* performance stats */
87 	uint64_t	missed;
88 	uint64_t	evicted;
89 	uint64_t	skipped;
90 } zcache;
91 
92 void zcache_kmem_reclaim(void);
93 
94 #define	ZCACHE_MINTIME (hz>>4) /* 62 ms */
95 
96 /*
97  * Move the supplied znode to the indicated state.  The mutex
98  * for the znode must be held by the caller.
99  */
100 static void
101 zcache_change_state(zcache_state_t *new_state, znode_t *zp)
102 {
103 	/* ASSERT(MUTEX_HELD(hash_mtx)); */
104 	ASSERT(zp->z_active);
105 
106 	if (zp->z_zcache_state) {
107 		ASSERT3U(zp->z_zcache_state->cnt, >=, 1);
108 		atomic_add_64(&zp->z_zcache_state->cnt, -1);
109 	}
110 	atomic_add_64(&new_state->cnt, 1);
111 	zp->z_zcache_state = new_state;
112 }
113 
114 static void
115 zfs_zcache_evict(znode_t *zp, kmutex_t *hash_mtx)
116 {
117 	zfsvfs_t *zfsvfs = zp->z_zfsvfs;
118 
119 	ASSERT(zp->z_phys);
120 	ASSERT(zp->z_dbuf_held);
121 
122 	zp->z_dbuf_held = 0;
123 	mutex_exit(&zp->z_lock);
124 	dmu_buf_rele(zp->z_dbuf);
125 	mutex_exit(hash_mtx);
126 	VFS_RELE(zfsvfs->z_vfs);
127 }
128 
129 /*
130  * Evict znodes from list until we've removed the specified number
131  */
132 static void
133 zcache_evict_state(zcache_state_t *state, int64_t cnt, zfsvfs_t *zfsvfs)
134 {
135 	int znodes_evicted = 0;
136 	znode_t *zp, *zp_prev;
137 	kmutex_t *hash_mtx;
138 
139 	ASSERT(state == zcache.mru || state == zcache.mfu);
140 
141 	mutex_enter(&state->mtx);
142 
143 	for (zp = list_tail(&state->list); zp; zp = zp_prev) {
144 		zp_prev = list_prev(&state->list, zp);
145 		if (zfsvfs && zp->z_zfsvfs != zfsvfs)
146 			continue;
147 		hash_mtx = ZFS_OBJ_MUTEX(zp);
148 		if (mutex_tryenter(hash_mtx)) {
149 			mutex_enter(&zp->z_lock);
150 			list_remove(&zp->z_zcache_state->list, zp);
151 			zp->z_zcache_state->lcnt -= 1;
152 			ASSERT3U(zp->z_zcache_state->cnt, >=, 1);
153 			atomic_add_64(&zp->z_zcache_state->cnt, -1);
154 			zp->z_zcache_state = NULL;
155 			zp->z_zcache_access = 0;
156 			/* drops z_lock and hash_mtx */
157 			zfs_zcache_evict(zp, hash_mtx);
158 			znodes_evicted += 1;
159 			atomic_add_64(&zcache.evicted, 1);
160 			if (znodes_evicted >= cnt)
161 				break;
162 		} else {
163 			atomic_add_64(&zcache.skipped, 1);
164 		}
165 	}
166 	mutex_exit(&state->mtx);
167 
168 	if (znodes_evicted < cnt)
169 		dprintf("only evicted %lld znodes from %x",
170 		    (longlong_t)znodes_evicted, state);
171 }
172 
173 static void
174 zcache_adjust(void)
175 {
176 	uint64_t mrucnt = zcache.mru->lcnt;
177 	uint64_t mfucnt = zcache.mfu->lcnt;
178 	uint64_t p = zcache.p;
179 	uint64_t c = zcache.c;
180 
181 	if (mrucnt > p)
182 		zcache_evict_state(zcache.mru, mrucnt - p, NULL);
183 
184 	if (mfucnt > 0 && mrucnt + mfucnt > c) {
185 		int64_t toevict = MIN(mfucnt, mrucnt + mfucnt - c);
186 		zcache_evict_state(zcache.mfu, toevict, NULL);
187 	}
188 }
189 
190 /*
191  * Flush all *evictable* data from the cache.
192  * NOTE: this will not touch "active" (i.e. referenced) data.
193  */
194 void
195 zfs_zcache_flush(zfsvfs_t *zfsvfs)
196 {
197 	zcache_evict_state(zcache.mru, zcache.mru->lcnt, zfsvfs);
198 	zcache_evict_state(zcache.mfu, zcache.mfu->lcnt, zfsvfs);
199 }
200 
201 static void
202 zcache_try_grow(int64_t cnt)
203 {
204 	int64_t size;
205 	/*
206 	 * If we're almost to the current target cache size,
207 	 * increment the target cache size
208 	 */
209 	size = zcache.mru->lcnt + zcache.mfu->lcnt;
210 	if ((zcache.c - size) <= 1) {
211 		atomic_add_64(&zcache.c, cnt);
212 		if (zcache.c > zcache.c_max)
213 			zcache.c = zcache.c_max;
214 		else if (zcache.p + cnt < zcache.c)
215 			atomic_add_64(&zcache.p, cnt);
216 	}
217 }
218 
219 /*
220  * This routine is called whenever a znode is accessed.
221  */
222 static void
223 zcache_access(znode_t *zp, kmutex_t *hash_mtx)
224 {
225 	ASSERT(MUTEX_HELD(hash_mtx));
226 
227 	if (zp->z_zcache_state == NULL) {
228 		/*
229 		 * This znode is not in the cache.
230 		 * Add the new znode to the MRU state.
231 		 */
232 
233 		zcache_try_grow(1);
234 
235 		ASSERT(zp->z_zcache_access == 0);
236 		zp->z_zcache_access = lbolt;
237 		zcache_change_state(zcache.mru, zp);
238 		mutex_exit(hash_mtx);
239 
240 		/*
241 		 * If we are using less than 2/3 of our total target
242 		 * cache size, bump up the target size for the MRU
243 		 * list.
244 		 */
245 		if (zcache.mru->lcnt + zcache.mfu->lcnt < zcache.c*2/3) {
246 			zcache.p = zcache.mru->lcnt + zcache.c/6;
247 		}
248 
249 		zcache_adjust();
250 
251 		atomic_add_64(&zcache.missed, 1);
252 	} else if (zp->z_zcache_state == zcache.mru) {
253 		/*
254 		 * This znode has been "accessed" only once so far,
255 		 * Move it to the MFU state.
256 		 */
257 		if (lbolt > zp->z_zcache_access + ZCACHE_MINTIME) {
258 			/*
259 			 * More than 125ms have passed since we
260 			 * instantiated this buffer.  Move it to the
261 			 * most frequently used state.
262 			 */
263 			zp->z_zcache_access = lbolt;
264 			zcache_change_state(zcache.mfu, zp);
265 		}
266 		atomic_add_64(&zcache.mru->hits, 1);
267 		mutex_exit(hash_mtx);
268 	} else {
269 		ASSERT(zp->z_zcache_state == zcache.mfu);
270 		/*
271 		 * This buffer has been accessed more than once.
272 		 * Keep it in the MFU state.
273 		 */
274 		atomic_add_64(&zcache.mfu->hits, 1);
275 		mutex_exit(hash_mtx);
276 	}
277 }
278 
279 static void
280 zcache_init(void)
281 {
282 	zcache.c = 20;
283 	zcache.c_max = 50;
284 
285 	zcache.mru = &ZCACHE_mru;
286 	zcache.mfu = &ZCACHE_mfu;
287 
288 	list_create(&zcache.mru->list, sizeof (znode_t),
289 	    offsetof(znode_t, z_zcache_node));
290 	list_create(&zcache.mfu->list, sizeof (znode_t),
291 	    offsetof(znode_t, z_zcache_node));
292 }
293 
294 static void
295 zcache_fini(void)
296 {
297 	zfs_zcache_flush(NULL);
298 
299 	list_destroy(&zcache.mru->list);
300 	list_destroy(&zcache.mfu->list);
301 }
302 
303 /*ARGSUSED*/
304 static void
305 znode_pageout_func(dmu_buf_t *dbuf, void *user_ptr)
306 {
307 	znode_t *zp = user_ptr;
308 	vnode_t *vp = ZTOV(zp);
309 
310 	if (vp->v_count == 0) {
311 		vn_invalid(vp);
312 		zfs_znode_free(zp);
313 	}
314 }
315 
316 /*ARGSUSED*/
317 static int
318 zfs_znode_cache_constructor(void *buf, void *cdrarg, int kmflags)
319 {
320 	znode_t *zp = buf;
321 
322 	zp->z_vnode = vn_alloc(KM_SLEEP);
323 	zp->z_vnode->v_data = (caddr_t)zp;
324 	mutex_init(&zp->z_lock, NULL, MUTEX_DEFAULT, NULL);
325 	rw_init(&zp->z_map_lock, NULL, RW_DEFAULT, NULL);
326 	rw_init(&zp->z_grow_lock, NULL, RW_DEFAULT, NULL);
327 	rw_init(&zp->z_append_lock, NULL, RW_DEFAULT, NULL);
328 	mutex_init(&zp->z_acl_lock, NULL, MUTEX_DEFAULT, NULL);
329 	zp->z_dbuf_held = 0;
330 	zp->z_dirlocks = 0;
331 	return (0);
332 }
333 
334 /*ARGSUSED*/
335 static void
336 zfs_znode_cache_destructor(void *buf, void *cdarg)
337 {
338 	znode_t *zp = buf;
339 
340 	ASSERT(zp->z_dirlocks == 0);
341 	mutex_destroy(&zp->z_lock);
342 	rw_destroy(&zp->z_map_lock);
343 	rw_destroy(&zp->z_grow_lock);
344 	rw_destroy(&zp->z_append_lock);
345 	mutex_destroy(&zp->z_acl_lock);
346 
347 	ASSERT(zp->z_dbuf_held == 0);
348 	ASSERT(ZTOV(zp)->v_count == 0);
349 	vn_free(ZTOV(zp));
350 }
351 
352 void
353 zfs_znode_init(void)
354 {
355 	/*
356 	 * Initialize zcache
357 	 */
358 	ASSERT(znode_cache == NULL);
359 	znode_cache = kmem_cache_create("zfs_znode_cache",
360 	    sizeof (znode_t), 0, zfs_znode_cache_constructor,
361 	    zfs_znode_cache_destructor, NULL, NULL, NULL, 0);
362 
363 	zcache_init();
364 }
365 
366 void
367 zfs_znode_fini(void)
368 {
369 	zcache_fini();
370 
371 	/*
372 	 * Cleanup vfs & vnode ops
373 	 */
374 	zfs_remove_op_tables();
375 
376 	/*
377 	 * Cleanup zcache
378 	 */
379 	if (znode_cache)
380 		kmem_cache_destroy(znode_cache);
381 	znode_cache = NULL;
382 }
383 
384 struct vnodeops *zfs_dvnodeops;
385 struct vnodeops *zfs_fvnodeops;
386 struct vnodeops *zfs_symvnodeops;
387 struct vnodeops *zfs_xdvnodeops;
388 struct vnodeops *zfs_evnodeops;
389 
390 void
391 zfs_remove_op_tables()
392 {
393 	/*
394 	 * Remove vfs ops
395 	 */
396 	ASSERT(zfsfstype);
397 	(void) vfs_freevfsops_by_type(zfsfstype);
398 	zfsfstype = 0;
399 
400 	/*
401 	 * Remove vnode ops
402 	 */
403 	if (zfs_dvnodeops)
404 		vn_freevnodeops(zfs_dvnodeops);
405 	if (zfs_fvnodeops)
406 		vn_freevnodeops(zfs_fvnodeops);
407 	if (zfs_symvnodeops)
408 		vn_freevnodeops(zfs_symvnodeops);
409 	if (zfs_xdvnodeops)
410 		vn_freevnodeops(zfs_xdvnodeops);
411 	if (zfs_evnodeops)
412 		vn_freevnodeops(zfs_evnodeops);
413 
414 	zfs_dvnodeops = NULL;
415 	zfs_fvnodeops = NULL;
416 	zfs_symvnodeops = NULL;
417 	zfs_xdvnodeops = NULL;
418 	zfs_evnodeops = NULL;
419 }
420 
421 extern const fs_operation_def_t zfs_dvnodeops_template[];
422 extern const fs_operation_def_t zfs_fvnodeops_template[];
423 extern const fs_operation_def_t zfs_xdvnodeops_template[];
424 extern const fs_operation_def_t zfs_symvnodeops_template[];
425 extern const fs_operation_def_t zfs_evnodeops_template[];
426 
427 int
428 zfs_create_op_tables()
429 {
430 	int error;
431 
432 	/*
433 	 * zfs_dvnodeops can be set if mod_remove() calls mod_installfs()
434 	 * due to a failure to remove the the 2nd modlinkage (zfs_modldrv).
435 	 * In this case we just return as the ops vectors are already set up.
436 	 */
437 	if (zfs_dvnodeops)
438 		return (0);
439 
440 	error = vn_make_ops(MNTTYPE_ZFS, zfs_dvnodeops_template,
441 	    &zfs_dvnodeops);
442 	if (error)
443 		return (error);
444 
445 	error = vn_make_ops(MNTTYPE_ZFS, zfs_fvnodeops_template,
446 	    &zfs_fvnodeops);
447 	if (error)
448 		return (error);
449 
450 	error = vn_make_ops(MNTTYPE_ZFS, zfs_symvnodeops_template,
451 	    &zfs_symvnodeops);
452 	if (error)
453 		return (error);
454 
455 	error = vn_make_ops(MNTTYPE_ZFS, zfs_xdvnodeops_template,
456 	    &zfs_xdvnodeops);
457 	if (error)
458 		return (error);
459 
460 	error = vn_make_ops(MNTTYPE_ZFS, zfs_evnodeops_template,
461 	    &zfs_evnodeops);
462 
463 	return (error);
464 }
465 
466 /*
467  * zfs_init_fs - Initialize the zfsvfs struct and the file system
468  *	incore "master" object.  Verify version compatibility.
469  */
470 int
471 zfs_init_fs(zfsvfs_t *zfsvfs, znode_t **zpp, cred_t *cr)
472 {
473 	extern int zfsfstype;
474 
475 	objset_t	*os = zfsvfs->z_os;
476 	uint64_t	zoid;
477 	uint64_t	version = ZFS_VERSION;
478 	int		i, error;
479 	dmu_object_info_t doi;
480 	dmu_objset_stats_t *stats;
481 
482 	*zpp = NULL;
483 
484 	/*
485 	 * XXX - hack to auto-create the pool root filesystem at
486 	 * the first attempted mount.
487 	 */
488 	if (dmu_object_info(os, MASTER_NODE_OBJ, &doi) == ENOENT) {
489 		dmu_tx_t *tx = dmu_tx_create(os);
490 
491 		dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, 3); /* master node */
492 		dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, 1); /* delete queue */
493 		dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT); /* root node */
494 		error = dmu_tx_assign(tx, TXG_WAIT);
495 		ASSERT3U(error, ==, 0);
496 		zfs_create_fs(os, cr, tx);
497 		dmu_tx_commit(tx);
498 	}
499 
500 	if (zap_lookup(os, MASTER_NODE_OBJ, ZFS_VERSION_OBJ, 8, 1, &version)) {
501 		return (EINVAL);
502 	} else if (version != ZFS_VERSION) {
503 		(void) printf("Mismatched versions:  File system "
504 		    "is version %lld on-disk format, which is "
505 		    "incompatible with this software version %lld!",
506 		    (u_longlong_t)version, ZFS_VERSION);
507 		return (ENOTSUP);
508 	}
509 
510 	/*
511 	 * The fsid is 64 bits, composed of an 8-bit fs type, which
512 	 * separates our fsid from any other filesystem types, and a
513 	 * 56-bit objset unique ID.  The objset unique ID is unique to
514 	 * all objsets open on this system, provided by unique_create().
515 	 * The 8-bit fs type must be put in the low bits of fsid[1]
516 	 * because that's where other Solaris filesystems put it.
517 	 */
518 	stats = kmem_alloc(sizeof (dmu_objset_stats_t), KM_SLEEP);
519 	dmu_objset_stats(os, stats);
520 	ASSERT((stats->dds_fsid_guid & ~((1ULL<<56)-1)) == 0);
521 	zfsvfs->z_vfs->vfs_fsid.val[0] = stats->dds_fsid_guid;
522 	zfsvfs->z_vfs->vfs_fsid.val[1] = ((stats->dds_fsid_guid>>32) << 8) |
523 	    zfsfstype & 0xFF;
524 	kmem_free(stats, sizeof (dmu_objset_stats_t));
525 	stats = NULL;
526 
527 	if (zap_lookup(os, MASTER_NODE_OBJ, ZFS_ROOT_OBJ, 8, 1, &zoid)) {
528 		return (EINVAL);
529 	}
530 	ASSERT(zoid != 0);
531 	zfsvfs->z_root = zoid;
532 
533 	/*
534 	 * Create the per mount vop tables.
535 	 */
536 
537 	/*
538 	 * Initialize zget mutex's
539 	 */
540 	for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
541 		mutex_init(&zfsvfs->z_hold_mtx[i], NULL, MUTEX_DEFAULT, NULL);
542 
543 	error = zfs_zget(zfsvfs, zoid, zpp);
544 	if (error)
545 		return (error);
546 	ASSERT3U((*zpp)->z_id, ==, zoid);
547 
548 	if (zap_lookup(os, MASTER_NODE_OBJ, ZFS_DELETE_QUEUE, 8, 1, &zoid)) {
549 		return (EINVAL);
550 	}
551 
552 	zfsvfs->z_dqueue = zoid;
553 
554 	/*
555 	 * Initialize delete head structure
556 	 * Thread(s) will be started/stopped via
557 	 * readonly_changed_cb() depending
558 	 * on whether this is rw/ro mount.
559 	 */
560 	list_create(&zfsvfs->z_delete_head.z_znodes,
561 	    sizeof (znode_t), offsetof(znode_t, z_list_node));
562 
563 	return (0);
564 }
565 
566 /*
567  * Construct a new znode/vnode and intialize.
568  *
569  * This does not do a call to dmu_set_user() that is
570  * up to the caller to do, in case you don't want to
571  * return the znode
572  */
573 znode_t *
574 zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, uint64_t obj_num, int blksz)
575 {
576 	znode_t	*zp;
577 	vnode_t *vp;
578 
579 	zp = kmem_cache_alloc(znode_cache, KM_SLEEP);
580 
581 	ASSERT(zp->z_dirlocks == NULL);
582 
583 	zp->z_phys = db->db_data;
584 	zp->z_zfsvfs = zfsvfs;
585 	zp->z_active = 1;
586 	zp->z_reap = 0;
587 	zp->z_atime_dirty = 0;
588 	zp->z_dbuf_held = 0;
589 	zp->z_mapcnt = 0;
590 	zp->z_last_itx = 0;
591 	zp->z_dbuf = db;
592 	zp->z_id = obj_num;
593 	zp->z_blksz = blksz;
594 	zp->z_seq = 0x7A4653;
595 
596 	bzero(&zp->z_zcache_node, sizeof (list_node_t));
597 
598 	mutex_enter(&zfsvfs->z_znodes_lock);
599 	list_insert_tail(&zfsvfs->z_all_znodes, zp);
600 	mutex_exit(&zfsvfs->z_znodes_lock);
601 
602 	vp = ZTOV(zp);
603 	vn_reinit(vp);
604 
605 	vp->v_vfsp = zfsvfs->z_parent->z_vfs;
606 	vp->v_type = IFTOVT((mode_t)zp->z_phys->zp_mode);
607 
608 	switch (vp->v_type) {
609 	case VDIR:
610 		if (zp->z_phys->zp_flags & ZFS_XATTR) {
611 			vn_setops(vp, zfs_xdvnodeops);
612 			vp->v_flag |= V_XATTRDIR;
613 		} else
614 			vn_setops(vp, zfs_dvnodeops);
615 		zp->z_zn_prefetch = B_TRUE; /* z_prefetch default is enabled */
616 		break;
617 	case VBLK:
618 	case VCHR:
619 		vp->v_rdev = (dev_t)zp->z_phys->zp_rdev;
620 		/*FALLTHROUGH*/
621 	case VFIFO:
622 	case VSOCK:
623 	case VDOOR:
624 		vn_setops(vp, zfs_fvnodeops);
625 		break;
626 	case VREG:
627 		vp->v_flag |= VMODSORT;
628 		vn_setops(vp, zfs_fvnodeops);
629 		break;
630 	case VLNK:
631 		vn_setops(vp, zfs_symvnodeops);
632 		break;
633 	default:
634 		vn_setops(vp, zfs_evnodeops);
635 		break;
636 	}
637 
638 	return (zp);
639 }
640 
641 static void
642 zfs_znode_dmu_init(znode_t *zp)
643 {
644 	znode_t		*nzp;
645 	zfsvfs_t	*zfsvfs = zp->z_zfsvfs;
646 	dmu_buf_t	*db = zp->z_dbuf;
647 
648 	mutex_enter(&zp->z_lock);
649 
650 	nzp = dmu_buf_set_user(db, zp, &zp->z_phys, znode_pageout_func);
651 
652 	/*
653 	 * there should be no
654 	 * concurrent zgets on this object.
655 	 */
656 	ASSERT3P(nzp, ==, NULL);
657 
658 	/*
659 	 * Slap on VROOT if we are the root znode
660 	 */
661 	if (zp->z_id == zfsvfs->z_root) {
662 		ZTOV(zp)->v_flag |= VROOT;
663 	}
664 
665 	zp->z_zcache_state = NULL;
666 	zp->z_zcache_access = 0;
667 
668 	ASSERT(zp->z_dbuf_held == 0);
669 	zp->z_dbuf_held = 1;
670 	VFS_HOLD(zfsvfs->z_vfs);
671 	mutex_exit(&zp->z_lock);
672 	vn_exists(ZTOV(zp));
673 }
674 
675 /*
676  * Create a new DMU object to hold a zfs znode.
677  *
678  *	IN:	dzp	- parent directory for new znode
679  *		vap	- file attributes for new znode
680  *		tx	- dmu transaction id for zap operations
681  *		cr	- credentials of caller
682  *		flag	- flags:
683  *			  IS_ROOT_NODE	- new object will be root
684  *			  IS_XATTR	- new object is an attribute
685  *			  IS_REPLAY	- intent log replay
686  *
687  *	OUT:	oid	- ID of created object
688  *
689  */
690 void
691 zfs_mknode(znode_t *dzp, vattr_t *vap, uint64_t *oid, dmu_tx_t *tx, cred_t *cr,
692 	uint_t flag, znode_t **zpp, int bonuslen)
693 {
694 	dmu_buf_t	*dbp;
695 	znode_phys_t	*pzp;
696 	znode_t		*zp;
697 	zfsvfs_t	*zfsvfs = dzp->z_zfsvfs;
698 	timestruc_t	now;
699 	uint64_t	gen;
700 	int		err;
701 
702 	ASSERT(vap && (vap->va_mask & (AT_TYPE|AT_MODE)) == (AT_TYPE|AT_MODE));
703 
704 	if (zfsvfs->z_assign >= TXG_INITIAL) {		/* ZIL replay */
705 		*oid = vap->va_nodeid;
706 		flag |= IS_REPLAY;
707 		now = vap->va_ctime;		/* see zfs_replay_create() */
708 		gen = vap->va_nblocks;		/* ditto */
709 	} else {
710 		*oid = 0;
711 		gethrestime(&now);
712 		gen = dmu_tx_get_txg(tx);
713 	}
714 
715 	/*
716 	 * Create a new DMU object.
717 	 */
718 	if (vap->va_type == VDIR) {
719 		if (flag & IS_REPLAY) {
720 			err = zap_create_claim(zfsvfs->z_os, *oid,
721 			    DMU_OT_DIRECTORY_CONTENTS,
722 			    DMU_OT_ZNODE, sizeof (znode_phys_t) + bonuslen, tx);
723 			ASSERT3U(err, ==, 0);
724 		} else {
725 			*oid = zap_create(zfsvfs->z_os,
726 			    DMU_OT_DIRECTORY_CONTENTS,
727 			    DMU_OT_ZNODE, sizeof (znode_phys_t) + bonuslen, tx);
728 		}
729 	} else {
730 		if (flag & IS_REPLAY) {
731 			err = dmu_object_claim(zfsvfs->z_os, *oid,
732 			    DMU_OT_PLAIN_FILE_CONTENTS, 0,
733 			    DMU_OT_ZNODE, sizeof (znode_phys_t) + bonuslen, tx);
734 			ASSERT3U(err, ==, 0);
735 		} else {
736 			*oid = dmu_object_alloc(zfsvfs->z_os,
737 			    DMU_OT_PLAIN_FILE_CONTENTS, 0,
738 			    DMU_OT_ZNODE, sizeof (znode_phys_t) + bonuslen, tx);
739 		}
740 	}
741 	dbp = dmu_bonus_hold(zfsvfs->z_os, *oid);
742 	dmu_buf_will_dirty(dbp, tx);
743 
744 	/*
745 	 * Initialize the znode physical data to zero.
746 	 */
747 	ASSERT(dbp->db_size >= sizeof (znode_phys_t));
748 	bzero(dbp->db_data, dbp->db_size);
749 	pzp = dbp->db_data;
750 
751 	/*
752 	 * If this is the root, fix up the half-initialized parent pointer
753 	 * to reference the just-allocated physical data area.
754 	 */
755 	if (flag & IS_ROOT_NODE) {
756 		dzp->z_phys = pzp;
757 		dzp->z_id = *oid;
758 	}
759 
760 	/*
761 	 * If parent is an xattr, so am I.
762 	 */
763 	if (dzp->z_phys->zp_flags & ZFS_XATTR)
764 		flag |= IS_XATTR;
765 
766 	if (vap->va_type == VBLK || vap->va_type == VCHR) {
767 		pzp->zp_rdev = vap->va_rdev;
768 	}
769 
770 	if (vap->va_type == VDIR) {
771 		pzp->zp_size = 2;		/* contents ("." and "..") */
772 		pzp->zp_links = (flag & (IS_ROOT_NODE | IS_XATTR)) ? 2 : 1;
773 	}
774 
775 	pzp->zp_parent = dzp->z_id;
776 	if (flag & IS_XATTR)
777 		pzp->zp_flags |= ZFS_XATTR;
778 
779 	pzp->zp_gen = gen;
780 
781 	ZFS_TIME_ENCODE(&now, pzp->zp_crtime);
782 	ZFS_TIME_ENCODE(&now, pzp->zp_ctime);
783 
784 	if (vap->va_mask & AT_ATIME) {
785 		ZFS_TIME_ENCODE(&vap->va_atime, pzp->zp_atime);
786 	} else {
787 		ZFS_TIME_ENCODE(&now, pzp->zp_atime);
788 	}
789 
790 	if (vap->va_mask & AT_MTIME) {
791 		ZFS_TIME_ENCODE(&vap->va_mtime, pzp->zp_mtime);
792 	} else {
793 		ZFS_TIME_ENCODE(&now, pzp->zp_mtime);
794 	}
795 
796 	pzp->zp_mode = MAKEIMODE(vap->va_type, vap->va_mode);
797 	zp = zfs_znode_alloc(zfsvfs, dbp, *oid, 0);
798 
799 	zfs_perm_init(zp, dzp, flag, vap, tx, cr);
800 
801 	if (zpp) {
802 		kmutex_t *hash_mtx = ZFS_OBJ_MUTEX(zp);
803 
804 		mutex_enter(hash_mtx);
805 		zfs_znode_dmu_init(zp);
806 		zcache_access(zp, hash_mtx);
807 		*zpp = zp;
808 	} else {
809 		ZTOV(zp)->v_count = 0;
810 		dmu_buf_rele(dbp);
811 		zfs_znode_free(zp);
812 	}
813 }
814 
815 int
816 zfs_zget(zfsvfs_t *zfsvfs, uint64_t obj_num, znode_t **zpp)
817 {
818 	dmu_object_info_t doi;
819 	dmu_buf_t	*db;
820 	znode_t		*zp;
821 
822 	*zpp = NULL;
823 
824 	ZFS_OBJ_HOLD_ENTER(zfsvfs, obj_num);
825 
826 	db = dmu_bonus_hold(zfsvfs->z_os, obj_num);
827 	if (db == NULL) {
828 		ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
829 		return (ENOENT);
830 	}
831 
832 	dmu_object_info_from_db(db, &doi);
833 	if (doi.doi_bonus_type != DMU_OT_ZNODE ||
834 	    doi.doi_bonus_size < sizeof (znode_phys_t)) {
835 		dmu_buf_rele(db);
836 		ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
837 		return (EINVAL);
838 	}
839 	dmu_buf_read(db);
840 
841 	ASSERT(db->db_object == obj_num);
842 	ASSERT(db->db_offset == -1);
843 	ASSERT(db->db_data != NULL);
844 
845 	zp = dmu_buf_get_user(db);
846 
847 	if (zp != NULL) {
848 		mutex_enter(&zp->z_lock);
849 
850 		ASSERT3U(zp->z_id, ==, obj_num);
851 		if (zp->z_reap) {
852 			dmu_buf_rele(db);
853 			mutex_exit(&zp->z_lock);
854 			ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
855 			return (ENOENT);
856 		} else if (zp->z_dbuf_held) {
857 			dmu_buf_rele(db);
858 		} else {
859 			zp->z_dbuf_held = 1;
860 			VFS_HOLD(zfsvfs->z_vfs);
861 		}
862 
863 		if (zp->z_active == 0) {
864 			zp->z_active = 1;
865 			if (list_link_active(&zp->z_zcache_node)) {
866 				mutex_enter(&zp->z_zcache_state->mtx);
867 				list_remove(&zp->z_zcache_state->list, zp);
868 				zp->z_zcache_state->lcnt -= 1;
869 				mutex_exit(&zp->z_zcache_state->mtx);
870 			}
871 		}
872 		VN_HOLD(ZTOV(zp));
873 		mutex_exit(&zp->z_lock);
874 		zcache_access(zp, ZFS_OBJ_MUTEX(zp));
875 		*zpp = zp;
876 		return (0);
877 	}
878 
879 	/*
880 	 * Not found create new znode/vnode
881 	 */
882 	zp = zfs_znode_alloc(zfsvfs, db, obj_num, doi.doi_data_block_size);
883 	ASSERT3U(zp->z_id, ==, obj_num);
884 	zfs_znode_dmu_init(zp);
885 	zcache_access(zp, ZFS_OBJ_MUTEX(zp));
886 	*zpp = zp;
887 	return (0);
888 }
889 
890 void
891 zfs_znode_delete(znode_t *zp, dmu_tx_t *tx)
892 {
893 	zfsvfs_t *zfsvfs = zp->z_zfsvfs;
894 	int error;
895 
896 	ZFS_OBJ_HOLD_ENTER(zfsvfs, zp->z_id);
897 	if (zp->z_phys->zp_acl.z_acl_extern_obj) {
898 		error = dmu_object_free(zfsvfs->z_os,
899 		    zp->z_phys->zp_acl.z_acl_extern_obj, tx);
900 		ASSERT3U(error, ==, 0);
901 	}
902 	if (zp->z_zcache_state) {
903 		ASSERT3U(zp->z_zcache_state->cnt, >=, 1);
904 		atomic_add_64(&zp->z_zcache_state->cnt, -1);
905 	}
906 	error = dmu_object_free(zfsvfs->z_os, zp->z_id, tx);
907 	ASSERT3U(error, ==, 0);
908 	zp->z_dbuf_held = 0;
909 	ZFS_OBJ_HOLD_EXIT(zfsvfs, zp->z_id);
910 	dmu_buf_rele(zp->z_dbuf);
911 }
912 
913 void
914 zfs_zinactive(znode_t *zp)
915 {
916 	vnode_t	*vp = ZTOV(zp);
917 	zfsvfs_t *zfsvfs = zp->z_zfsvfs;
918 	uint64_t z_id = zp->z_id;
919 
920 	ASSERT(zp->z_dbuf_held && zp->z_phys);
921 
922 	/*
923 	 * Don't allow a zfs_zget() while were trying to release this znode
924 	 */
925 	ZFS_OBJ_HOLD_ENTER(zfsvfs, z_id);
926 
927 	mutex_enter(&zp->z_lock);
928 	mutex_enter(&vp->v_lock);
929 	vp->v_count--;
930 	if (vp->v_count > 0 || vn_has_cached_data(vp)) {
931 		/*
932 		 * If the hold count is greater than zero, somebody has
933 		 * obtained a new reference on this znode while we were
934 		 * processing it here, so we are done.  If we still have
935 		 * mapped pages then we are also done, since we don't
936 		 * want to inactivate the znode until the pages get pushed.
937 		 *
938 		 * XXX - if vn_has_cached_data(vp) is true, but count == 0,
939 		 * this seems like it would leave the znode hanging with
940 		 * no chance to go inactive...
941 		 */
942 		mutex_exit(&vp->v_lock);
943 		mutex_exit(&zp->z_lock);
944 		ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
945 		return;
946 	}
947 	mutex_exit(&vp->v_lock);
948 	zp->z_active = 0;
949 
950 	/*
951 	 * If this was the last reference to a file with no links,
952 	 * remove the file from the file system.
953 	 */
954 	if (zp->z_reap) {
955 		mutex_exit(&zp->z_lock);
956 		ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
957 		ASSERT3U(zp->z_zcache_state->cnt, >=, 1);
958 		atomic_add_64(&zp->z_zcache_state->cnt, -1);
959 		zp->z_zcache_state = NULL;
960 		/* XATTR files are not put on the delete queue */
961 		if (zp->z_phys->zp_flags & ZFS_XATTR) {
962 			zfs_rmnode(zp);
963 		} else {
964 			mutex_enter(&zfsvfs->z_delete_head.z_mutex);
965 			list_insert_tail(&zfsvfs->z_delete_head.z_znodes, zp);
966 			zfsvfs->z_delete_head.z_znode_count++;
967 			cv_broadcast(&zfsvfs->z_delete_head.z_cv);
968 			mutex_exit(&zfsvfs->z_delete_head.z_mutex);
969 		}
970 		VFS_RELE(zfsvfs->z_vfs);
971 		return;
972 	}
973 
974 	/*
975 	 * If the file system for this znode is no longer mounted,
976 	 * evict the znode now, don't put it in the cache.
977 	 */
978 	if (zfsvfs->z_unmounted1) {
979 		zfs_zcache_evict(zp, ZFS_OBJ_MUTEX(zp));
980 		return;
981 	}
982 
983 	/* put znode on evictable list */
984 	mutex_enter(&zp->z_zcache_state->mtx);
985 	list_insert_head(&zp->z_zcache_state->list, zp);
986 	zp->z_zcache_state->lcnt += 1;
987 	mutex_exit(&zp->z_zcache_state->mtx);
988 	mutex_exit(&zp->z_lock);
989 	ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
990 }
991 
992 void
993 zfs_znode_free(znode_t *zp)
994 {
995 	zfsvfs_t *zfsvfs = zp->z_zfsvfs;
996 
997 	mutex_enter(&zfsvfs->z_znodes_lock);
998 	list_remove(&zfsvfs->z_all_znodes, zp);
999 	mutex_exit(&zfsvfs->z_znodes_lock);
1000 
1001 	kmem_cache_free(znode_cache, zp);
1002 }
1003 
1004 void
1005 zfs_time_stamper_locked(znode_t *zp, uint_t flag, dmu_tx_t *tx)
1006 {
1007 	timestruc_t	now;
1008 
1009 	ASSERT(MUTEX_HELD(&zp->z_lock));
1010 
1011 	gethrestime(&now);
1012 
1013 	if (tx) {
1014 		dmu_buf_will_dirty(zp->z_dbuf, tx);
1015 		zp->z_atime_dirty = 0;
1016 		zp->z_seq++;
1017 	} else {
1018 		zp->z_atime_dirty = 1;
1019 	}
1020 
1021 	if (flag & AT_ATIME)
1022 		ZFS_TIME_ENCODE(&now, zp->z_phys->zp_atime);
1023 
1024 	if (flag & AT_MTIME)
1025 		ZFS_TIME_ENCODE(&now, zp->z_phys->zp_mtime);
1026 
1027 	if (flag & AT_CTIME)
1028 		ZFS_TIME_ENCODE(&now, zp->z_phys->zp_ctime);
1029 }
1030 
1031 /*
1032  * Update the requested znode timestamps with the current time.
1033  * If we are in a transaction, then go ahead and mark the znode
1034  * dirty in the transaction so the timestamps will go to disk.
1035  * Otherwise, we will get pushed next time the znode is updated
1036  * in a transaction, or when this znode eventually goes inactive.
1037  *
1038  * Why is this OK?
1039  *  1 - Only the ACCESS time is ever updated outside of a transaction.
1040  *  2 - Multiple consecutive updates will be collapsed into a single
1041  *	znode update by the transaction grouping semantics of the DMU.
1042  */
1043 void
1044 zfs_time_stamper(znode_t *zp, uint_t flag, dmu_tx_t *tx)
1045 {
1046 	mutex_enter(&zp->z_lock);
1047 	zfs_time_stamper_locked(zp, flag, tx);
1048 	mutex_exit(&zp->z_lock);
1049 }
1050 
1051 /*
1052  * Grow the block size for a file.  This may involve migrating data
1053  * from the bonus buffer into a data block (when we grow beyond the
1054  * bonus buffer data area).
1055  *
1056  *	IN:	zp	- znode of file to free data in.
1057  *		size	- requested block size
1058  *		tx	- open transaction.
1059  *
1060  * 	RETURN:	0 if success
1061  *		error code if failure
1062  *
1063  * NOTE: this function assumes that the znode is write locked.
1064  */
1065 int
1066 zfs_grow_blocksize(znode_t *zp, uint64_t size, dmu_tx_t *tx)
1067 {
1068 	int		error;
1069 	u_longlong_t	dummy;
1070 
1071 	ASSERT(rw_write_held(&zp->z_grow_lock));
1072 
1073 	if (size <= zp->z_blksz)
1074 		return (0);
1075 	/*
1076 	 * If the file size is already greater than the current blocksize,
1077 	 * we will not grow.  If there is more than one block in a file,
1078 	 * the blocksize cannot change.
1079 	 */
1080 	if (zp->z_blksz && zp->z_phys->zp_size > zp->z_blksz)
1081 		return (0);
1082 
1083 	error = dmu_object_set_blocksize(zp->z_zfsvfs->z_os, zp->z_id,
1084 	    size, 0, tx);
1085 	if (error == ENOTSUP)
1086 		return (0);
1087 	ASSERT3U(error, ==, 0);
1088 
1089 	/* What blocksize did we actually get? */
1090 	dmu_object_size_from_db(zp->z_dbuf, &zp->z_blksz, &dummy);
1091 
1092 	return (0);
1093 }
1094 
1095 /*
1096  * This is a dummy interface used when pvn_vplist_dirty() should *not*
1097  * be calling back into the fs for a putpage().  E.g.: when truncating
1098  * a file, the pages being "thrown away* don't need to be written out.
1099  */
1100 /* ARGSUSED */
1101 static int
1102 zfs_no_putpage(vnode_t *vp, page_t *pp, u_offset_t *offp, size_t *lenp,
1103     int flags, cred_t *cr)
1104 {
1105 	ASSERT(0);
1106 	return (0);
1107 }
1108 
1109 /*
1110  * Free space in a file.  Currently, this function only
1111  * supports freeing space at the end of the file.
1112  *
1113  *	IN:	zp	- znode of file to free data in.
1114  *		from	- start of section to free.
1115  *		len	- length of section to free (0 => to EOF).
1116  *		flag	- current file open mode flags.
1117  *		tx	- open transaction.
1118  *
1119  * 	RETURN:	0 if success
1120  *		error code if failure
1121  */
1122 int
1123 zfs_freesp(znode_t *zp, uint64_t from, uint64_t len, int flag, dmu_tx_t *tx,
1124 	cred_t *cr)
1125 {
1126 	vnode_t *vp = ZTOV(zp);
1127 	uint64_t size = zp->z_phys->zp_size;
1128 	uint64_t end = from + len;
1129 	int have_grow_lock, error;
1130 
1131 	if (ZTOV(zp)->v_type == VFIFO)
1132 		return (0);
1133 
1134 	have_grow_lock = RW_WRITE_HELD(&zp->z_grow_lock);
1135 
1136 	/*
1137 	 * Nothing to do if file already at desired length.
1138 	 */
1139 	if (len == 0 && size == from) {
1140 		return (0);
1141 	}
1142 
1143 	/*
1144 	 * Check for any locks in the region to be freed.
1145 	 */
1146 	if (MANDLOCK(vp, (mode_t)zp->z_phys->zp_mode)) {
1147 		uint64_t	start;
1148 
1149 		if (size > from)
1150 			start = from;
1151 		else
1152 			start = size;
1153 		if (error = chklock(vp, FWRITE, start, 0, flag, NULL))
1154 			return (error);
1155 	}
1156 
1157 	if (end > zp->z_blksz && (!ISP2(zp->z_blksz) ||
1158 	    zp->z_blksz < zp->z_zfsvfs->z_max_blksz)) {
1159 		uint64_t new_blksz;
1160 		/*
1161 		 * We are growing the file past the current block size.
1162 		 */
1163 		if (zp->z_blksz > zp->z_zfsvfs->z_max_blksz) {
1164 			ASSERT(!ISP2(zp->z_blksz));
1165 			new_blksz = MIN(end, SPA_MAXBLOCKSIZE);
1166 		} else {
1167 			new_blksz = MIN(end, zp->z_zfsvfs->z_max_blksz);
1168 		}
1169 		error = zfs_grow_blocksize(zp, new_blksz, tx);
1170 		ASSERT(error == 0);
1171 	}
1172 	if (end > size || len == 0)
1173 		zp->z_phys->zp_size = end;
1174 	if (from > size)
1175 		return (0);
1176 
1177 	if (have_grow_lock)
1178 		rw_downgrade(&zp->z_grow_lock);
1179 	/*
1180 	 * Clear any mapped pages in the truncated region.
1181 	 */
1182 	rw_enter(&zp->z_map_lock, RW_WRITER);
1183 	if (vn_has_cached_data(vp)) {
1184 		page_t *pp;
1185 		uint64_t start = from & PAGEMASK;
1186 		int off = from & PAGEOFFSET;
1187 
1188 		if (off != 0 && (pp = page_lookup(vp, start, SE_SHARED))) {
1189 			/*
1190 			 * We need to zero a partial page.
1191 			 */
1192 			pagezero(pp, off, PAGESIZE - off);
1193 			start += PAGESIZE;
1194 			page_unlock(pp);
1195 		}
1196 		error = pvn_vplist_dirty(vp, start, zfs_no_putpage,
1197 		    B_INVAL | B_TRUNC, cr);
1198 		ASSERT(error == 0);
1199 	}
1200 	rw_exit(&zp->z_map_lock);
1201 
1202 	if (!have_grow_lock)
1203 		rw_enter(&zp->z_grow_lock, RW_READER);
1204 
1205 	if (len == 0)
1206 		len = -1;
1207 	else if (end > size)
1208 		len = size - from;
1209 	dmu_free_range(zp->z_zfsvfs->z_os, zp->z_id, from, len, tx);
1210 
1211 	if (!have_grow_lock)
1212 		rw_exit(&zp->z_grow_lock);
1213 
1214 	return (0);
1215 }
1216 
1217 
1218 void
1219 zfs_create_fs(objset_t *os, cred_t *cr, dmu_tx_t *tx)
1220 {
1221 	zfsvfs_t	zfsvfs;
1222 	uint64_t	moid, doid, roid = 0;
1223 	uint64_t	version = ZFS_VERSION;
1224 	int		error;
1225 	znode_t		*rootzp = NULL;
1226 	vnode_t		*vp;
1227 	vattr_t		vattr;
1228 
1229 	/*
1230 	 * First attempt to create master node.
1231 	 */
1232 	moid = MASTER_NODE_OBJ;
1233 	error = zap_create_claim(os, moid, DMU_OT_MASTER_NODE,
1234 	    DMU_OT_NONE, 0, tx);
1235 	ASSERT(error == 0);
1236 
1237 	/*
1238 	 * Set starting attributes.
1239 	 */
1240 
1241 	error = zap_update(os, moid, ZFS_VERSION_OBJ, 8, 1, &version, tx);
1242 	ASSERT(error == 0);
1243 
1244 	/*
1245 	 * Create a delete queue.
1246 	 */
1247 	doid = zap_create(os, DMU_OT_DELETE_QUEUE, DMU_OT_NONE, 0, tx);
1248 
1249 	error = zap_add(os, moid, ZFS_DELETE_QUEUE, 8, 1, &doid, tx);
1250 	ASSERT(error == 0);
1251 
1252 	/*
1253 	 * Create root znode.  Create minimal znode/vnode/zfsvfs
1254 	 * to allow zfs_mknode to work.
1255 	 */
1256 	vattr.va_mask = AT_MODE|AT_UID|AT_GID|AT_TYPE;
1257 	vattr.va_type = VDIR;
1258 	vattr.va_mode = S_IFDIR|0755;
1259 	vattr.va_uid = 0;
1260 	vattr.va_gid = 3;
1261 
1262 	rootzp = kmem_cache_alloc(znode_cache, KM_SLEEP);
1263 	rootzp->z_zfsvfs = &zfsvfs;
1264 	rootzp->z_active = 1;
1265 	rootzp->z_reap = 0;
1266 	rootzp->z_atime_dirty = 0;
1267 	rootzp->z_dbuf_held = 0;
1268 
1269 	vp = ZTOV(rootzp);
1270 	vn_reinit(vp);
1271 	vp->v_type = VDIR;
1272 
1273 	bzero(&zfsvfs, sizeof (zfsvfs_t));
1274 
1275 	zfsvfs.z_os = os;
1276 	zfsvfs.z_assign = TXG_NOWAIT;
1277 	zfsvfs.z_parent = &zfsvfs;
1278 
1279 	mutex_init(&zfsvfs.z_znodes_lock, NULL, MUTEX_DEFAULT, NULL);
1280 	list_create(&zfsvfs.z_all_znodes, sizeof (znode_t),
1281 	    offsetof(znode_t, z_link_node));
1282 
1283 	zfs_mknode(rootzp, &vattr, &roid, tx, cr, IS_ROOT_NODE, NULL, 0);
1284 	ASSERT3U(rootzp->z_id, ==, roid);
1285 	error = zap_add(os, moid, ZFS_ROOT_OBJ, 8, 1, &roid, tx);
1286 	ASSERT(error == 0);
1287 
1288 	ZTOV(rootzp)->v_count = 0;
1289 	kmem_cache_free(znode_cache, rootzp);
1290 }
1291