xref: /illumos-gate/usr/src/uts/common/fs/zfs/dmu_objset.c (revision 13b136d3061155363c62c9f6568d25b8b27da8f6)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright (c) 2012, 2017 by Delphix. All rights reserved.
25  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
26  * Copyright 2019 Joyent, Inc.
27  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
28  * Copyright (c) 2015, STRATO AG, Inc. All rights reserved.
29  * Copyright (c) 2014 Integros [integros.com]
30  * Copyright 2017 Nexenta Systems, Inc.
31  */
32 
33 /* Portions Copyright 2010 Robert Milkowski */
34 
35 #include <sys/zfeature.h>
36 #include <sys/cred.h>
37 #include <sys/zfs_context.h>
38 #include <sys/dmu_objset.h>
39 #include <sys/dsl_dir.h>
40 #include <sys/dsl_dataset.h>
41 #include <sys/dsl_prop.h>
42 #include <sys/dsl_pool.h>
43 #include <sys/dsl_synctask.h>
44 #include <sys/dsl_deleg.h>
45 #include <sys/dnode.h>
46 #include <sys/dbuf.h>
47 #include <sys/zvol.h>
48 #include <sys/dmu_tx.h>
49 #include <sys/zap.h>
50 #include <sys/zil.h>
51 #include <sys/dmu_impl.h>
52 #include <sys/zfs_ioctl.h>
53 #include <sys/sa.h>
54 #include <sys/zfs_onexit.h>
55 #include <sys/dsl_destroy.h>
56 #include <sys/vdev.h>
57 #include <sys/zfeature.h>
58 #include <sys/spa_impl.h>
59 #include <sys/dmu_recv.h>
60 #include <sys/zfs_project.h>
61 #include "zfs_namecheck.h"
62 
63 /*
64  * Needed to close a window in dnode_move() that allows the objset to be freed
65  * before it can be safely accessed.
66  */
67 krwlock_t os_lock;
68 
69 /*
70  * Tunable to overwrite the maximum number of threads for the parallization
71  * of dmu_objset_find_dp, needed to speed up the import of pools with many
72  * datasets.
73  * Default is 4 times the number of leaf vdevs.
74  */
75 int dmu_find_threads = 0;
76 
77 /*
78  * Backfill lower metadnode objects after this many have been freed.
79  * Backfilling negatively impacts object creation rates, so only do it
80  * if there are enough holes to fill.
81  */
82 int dmu_rescan_dnode_threshold = 131072;
83 
84 static void dmu_objset_find_dp_cb(void *arg);
85 
86 static void dmu_objset_upgrade(objset_t *os, dmu_objset_upgrade_cb_t cb);
87 static void dmu_objset_upgrade_stop(objset_t *os);
88 
89 void
90 dmu_objset_init(void)
91 {
92 	rw_init(&os_lock, NULL, RW_DEFAULT, NULL);
93 }
94 
95 void
96 dmu_objset_fini(void)
97 {
98 	rw_destroy(&os_lock);
99 }
100 
101 spa_t *
102 dmu_objset_spa(objset_t *os)
103 {
104 	return (os->os_spa);
105 }
106 
107 zilog_t *
108 dmu_objset_zil(objset_t *os)
109 {
110 	return (os->os_zil);
111 }
112 
113 dsl_pool_t *
114 dmu_objset_pool(objset_t *os)
115 {
116 	dsl_dataset_t *ds;
117 
118 	if ((ds = os->os_dsl_dataset) != NULL && ds->ds_dir)
119 		return (ds->ds_dir->dd_pool);
120 	else
121 		return (spa_get_dsl(os->os_spa));
122 }
123 
124 dsl_dataset_t *
125 dmu_objset_ds(objset_t *os)
126 {
127 	return (os->os_dsl_dataset);
128 }
129 
130 dmu_objset_type_t
131 dmu_objset_type(objset_t *os)
132 {
133 	return (os->os_phys->os_type);
134 }
135 
136 void
137 dmu_objset_name(objset_t *os, char *buf)
138 {
139 	dsl_dataset_name(os->os_dsl_dataset, buf);
140 }
141 
142 uint64_t
143 dmu_objset_id(objset_t *os)
144 {
145 	dsl_dataset_t *ds = os->os_dsl_dataset;
146 
147 	return (ds ? ds->ds_object : 0);
148 }
149 
150 uint64_t
151 dmu_objset_dnodesize(objset_t *os)
152 {
153 	return (os->os_dnodesize);
154 }
155 
156 zfs_sync_type_t
157 dmu_objset_syncprop(objset_t *os)
158 {
159 	return (os->os_sync);
160 }
161 
162 zfs_logbias_op_t
163 dmu_objset_logbias(objset_t *os)
164 {
165 	return (os->os_logbias);
166 }
167 
168 static void
169 checksum_changed_cb(void *arg, uint64_t newval)
170 {
171 	objset_t *os = arg;
172 
173 	/*
174 	 * Inheritance should have been done by now.
175 	 */
176 	ASSERT(newval != ZIO_CHECKSUM_INHERIT);
177 
178 	os->os_checksum = zio_checksum_select(newval, ZIO_CHECKSUM_ON_VALUE);
179 }
180 
181 static void
182 compression_changed_cb(void *arg, uint64_t newval)
183 {
184 	objset_t *os = arg;
185 
186 	/*
187 	 * Inheritance and range checking should have been done by now.
188 	 */
189 	ASSERT(newval != ZIO_COMPRESS_INHERIT);
190 
191 	os->os_compress = zio_compress_select(os->os_spa, newval,
192 	    ZIO_COMPRESS_ON);
193 }
194 
195 static void
196 copies_changed_cb(void *arg, uint64_t newval)
197 {
198 	objset_t *os = arg;
199 
200 	/*
201 	 * Inheritance and range checking should have been done by now.
202 	 */
203 	ASSERT(newval > 0);
204 	ASSERT(newval <= spa_max_replication(os->os_spa));
205 
206 	os->os_copies = newval;
207 }
208 
209 static void
210 dedup_changed_cb(void *arg, uint64_t newval)
211 {
212 	objset_t *os = arg;
213 	spa_t *spa = os->os_spa;
214 	enum zio_checksum checksum;
215 
216 	/*
217 	 * Inheritance should have been done by now.
218 	 */
219 	ASSERT(newval != ZIO_CHECKSUM_INHERIT);
220 
221 	checksum = zio_checksum_dedup_select(spa, newval, ZIO_CHECKSUM_OFF);
222 
223 	os->os_dedup_checksum = checksum & ZIO_CHECKSUM_MASK;
224 	os->os_dedup_verify = !!(checksum & ZIO_CHECKSUM_VERIFY);
225 }
226 
227 static void
228 primary_cache_changed_cb(void *arg, uint64_t newval)
229 {
230 	objset_t *os = arg;
231 
232 	/*
233 	 * Inheritance and range checking should have been done by now.
234 	 */
235 	ASSERT(newval == ZFS_CACHE_ALL || newval == ZFS_CACHE_NONE ||
236 	    newval == ZFS_CACHE_METADATA);
237 
238 	os->os_primary_cache = newval;
239 }
240 
241 static void
242 secondary_cache_changed_cb(void *arg, uint64_t newval)
243 {
244 	objset_t *os = arg;
245 
246 	/*
247 	 * Inheritance and range checking should have been done by now.
248 	 */
249 	ASSERT(newval == ZFS_CACHE_ALL || newval == ZFS_CACHE_NONE ||
250 	    newval == ZFS_CACHE_METADATA);
251 
252 	os->os_secondary_cache = newval;
253 }
254 
255 static void
256 sync_changed_cb(void *arg, uint64_t newval)
257 {
258 	objset_t *os = arg;
259 
260 	/*
261 	 * Inheritance and range checking should have been done by now.
262 	 */
263 	ASSERT(newval == ZFS_SYNC_STANDARD || newval == ZFS_SYNC_ALWAYS ||
264 	    newval == ZFS_SYNC_DISABLED);
265 
266 	os->os_sync = newval;
267 	if (os->os_zil)
268 		zil_set_sync(os->os_zil, newval);
269 }
270 
271 static void
272 redundant_metadata_changed_cb(void *arg, uint64_t newval)
273 {
274 	objset_t *os = arg;
275 
276 	/*
277 	 * Inheritance and range checking should have been done by now.
278 	 */
279 	ASSERT(newval == ZFS_REDUNDANT_METADATA_ALL ||
280 	    newval == ZFS_REDUNDANT_METADATA_MOST);
281 
282 	os->os_redundant_metadata = newval;
283 }
284 
285 static void
286 dnodesize_changed_cb(void *arg, uint64_t newval)
287 {
288 	objset_t *os = arg;
289 
290 	switch (newval) {
291 	case ZFS_DNSIZE_LEGACY:
292 		os->os_dnodesize = DNODE_MIN_SIZE;
293 		break;
294 	case ZFS_DNSIZE_AUTO:
295 		/*
296 		 * Choose a dnode size that will work well for most
297 		 * workloads if the user specified "auto". Future code
298 		 * improvements could dynamically select a dnode size
299 		 * based on observed workload patterns.
300 		 */
301 		os->os_dnodesize = DNODE_MIN_SIZE * 2;
302 		break;
303 	case ZFS_DNSIZE_1K:
304 	case ZFS_DNSIZE_2K:
305 	case ZFS_DNSIZE_4K:
306 	case ZFS_DNSIZE_8K:
307 	case ZFS_DNSIZE_16K:
308 		os->os_dnodesize = newval;
309 		break;
310 	}
311 }
312 
313 static void
314 smallblk_changed_cb(void *arg, uint64_t newval)
315 {
316 	objset_t *os = arg;
317 
318 	/*
319 	 * Inheritance and range checking should have been done by now.
320 	 */
321 	ASSERT(newval <= SPA_OLD_MAXBLOCKSIZE);
322 	ASSERT(ISP2(newval));
323 
324 	os->os_zpl_special_smallblock = newval;
325 }
326 
327 static void
328 logbias_changed_cb(void *arg, uint64_t newval)
329 {
330 	objset_t *os = arg;
331 
332 	ASSERT(newval == ZFS_LOGBIAS_LATENCY ||
333 	    newval == ZFS_LOGBIAS_THROUGHPUT);
334 	os->os_logbias = newval;
335 	if (os->os_zil)
336 		zil_set_logbias(os->os_zil, newval);
337 }
338 
339 static void
340 recordsize_changed_cb(void *arg, uint64_t newval)
341 {
342 	objset_t *os = arg;
343 
344 	os->os_recordsize = newval;
345 }
346 
347 void
348 dmu_objset_byteswap(void *buf, size_t size)
349 {
350 	objset_phys_t *osp = buf;
351 
352 	ASSERT(size == OBJSET_PHYS_SIZE_V1 || size == OBJSET_PHYS_SIZE_V2 ||
353 	    size == sizeof (objset_phys_t));
354 	dnode_byteswap(&osp->os_meta_dnode);
355 	byteswap_uint64_array(&osp->os_zil_header, sizeof (zil_header_t));
356 	osp->os_type = BSWAP_64(osp->os_type);
357 	osp->os_flags = BSWAP_64(osp->os_flags);
358 	if (size >= OBJSET_PHYS_SIZE_V2) {
359 		dnode_byteswap(&osp->os_userused_dnode);
360 		dnode_byteswap(&osp->os_groupused_dnode);
361 		if (size >= sizeof (objset_phys_t))
362 			dnode_byteswap(&osp->os_projectused_dnode);
363 	}
364 }
365 
366 /*
367  * The hash is a CRC-based hash of the objset_t pointer and the object number.
368  */
369 static uint64_t
370 dnode_hash(const objset_t *os, uint64_t obj)
371 {
372 	uintptr_t osv = (uintptr_t)os;
373 	uint64_t crc = -1ULL;
374 
375 	ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
376 	/*
377 	 * The low 6 bits of the pointer don't have much entropy, because
378 	 * the objset_t is larger than 2^6 bytes long.
379 	 */
380 	crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
381 	crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
382 	crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
383 	crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 16)) & 0xFF];
384 
385 	crc ^= (osv>>14) ^ (obj>>24);
386 
387 	return (crc);
388 }
389 
390 unsigned int
391 dnode_multilist_index_func(multilist_t *ml, void *obj)
392 {
393 	dnode_t *dn = obj;
394 	return (dnode_hash(dn->dn_objset, dn->dn_object) %
395 	    multilist_get_num_sublists(ml));
396 }
397 
398 /*
399  * Instantiates the objset_t in-memory structure corresponding to the
400  * objset_phys_t that's pointed to by the specified blkptr_t.
401  */
402 int
403 dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
404     objset_t **osp)
405 {
406 	objset_t *os;
407 	int i, err;
408 
409 	ASSERT(ds == NULL || MUTEX_HELD(&ds->ds_opening_lock));
410 
411 #if 0
412 	/*
413 	 * The $ORIGIN dataset (if it exists) doesn't have an associated
414 	 * objset, so there's no reason to open it. The $ORIGIN dataset
415 	 * will not exist on pools older than SPA_VERSION_ORIGIN.
416 	 */
417 	if (ds != NULL && spa_get_dsl(spa) != NULL &&
418 	    spa_get_dsl(spa)->dp_origin_snap != NULL) {
419 		ASSERT3P(ds->ds_dir, !=,
420 		    spa_get_dsl(spa)->dp_origin_snap->ds_dir);
421 	}
422 #endif
423 
424 	os = kmem_zalloc(sizeof (objset_t), KM_SLEEP);
425 	os->os_dsl_dataset = ds;
426 	os->os_spa = spa;
427 	os->os_rootbp = bp;
428 	if (!BP_IS_HOLE(os->os_rootbp)) {
429 		arc_flags_t aflags = ARC_FLAG_WAIT;
430 		zbookmark_phys_t zb;
431 		int size;
432 		enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
433 		SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
434 		    ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
435 
436 		if (DMU_OS_IS_L2CACHEABLE(os))
437 			aflags |= ARC_FLAG_L2CACHE;
438 
439 		if (ds != NULL && ds->ds_dir->dd_crypto_obj != 0) {
440 			ASSERT3U(BP_GET_COMPRESS(bp), ==, ZIO_COMPRESS_OFF);
441 			ASSERT(BP_IS_AUTHENTICATED(bp));
442 			zio_flags |= ZIO_FLAG_RAW;
443 		}
444 
445 		dprintf_bp(os->os_rootbp, "reading %s", "");
446 		err = arc_read(NULL, spa, os->os_rootbp,
447 		    arc_getbuf_func, &os->os_phys_buf,
448 		    ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
449 		if (err != 0) {
450 			kmem_free(os, sizeof (objset_t));
451 			/* convert checksum errors into IO errors */
452 			if (err == ECKSUM)
453 				err = SET_ERROR(EIO);
454 			return (err);
455 		}
456 
457 		if (spa_version(spa) < SPA_VERSION_USERSPACE)
458 			size = OBJSET_PHYS_SIZE_V1;
459 		else if (!spa_feature_is_enabled(spa,
460 		    SPA_FEATURE_PROJECT_QUOTA))
461 			size = OBJSET_PHYS_SIZE_V2;
462 		else
463 			size = sizeof (objset_phys_t);
464 
465 		/* Increase the blocksize if we are permitted. */
466 		if (arc_buf_size(os->os_phys_buf) < size) {
467 			arc_buf_t *buf = arc_alloc_buf(spa, &os->os_phys_buf,
468 			    ARC_BUFC_METADATA, size);
469 			bzero(buf->b_data, size);
470 			bcopy(os->os_phys_buf->b_data, buf->b_data,
471 			    arc_buf_size(os->os_phys_buf));
472 			arc_buf_destroy(os->os_phys_buf, &os->os_phys_buf);
473 			os->os_phys_buf = buf;
474 		}
475 
476 		os->os_phys = os->os_phys_buf->b_data;
477 		os->os_flags = os->os_phys->os_flags;
478 	} else {
479 		int size = spa_version(spa) >= SPA_VERSION_USERSPACE ?
480 		    sizeof (objset_phys_t) : OBJSET_PHYS_SIZE_V1;
481 		os->os_phys_buf = arc_alloc_buf(spa, &os->os_phys_buf,
482 		    ARC_BUFC_METADATA, size);
483 		os->os_phys = os->os_phys_buf->b_data;
484 		bzero(os->os_phys, size);
485 	}
486 
487 	/*
488 	 * Note: the changed_cb will be called once before the register
489 	 * func returns, thus changing the checksum/compression from the
490 	 * default (fletcher2/off).  Snapshots don't need to know about
491 	 * checksum/compression/copies.
492 	 */
493 	if (ds != NULL) {
494 		boolean_t needlock = B_FALSE;
495 
496 		os->os_encrypted = (ds->ds_dir->dd_crypto_obj != 0);
497 
498 		/*
499 		 * Note: it's valid to open the objset if the dataset is
500 		 * long-held, in which case the pool_config lock will not
501 		 * be held.
502 		 */
503 		if (!dsl_pool_config_held(dmu_objset_pool(os))) {
504 			needlock = B_TRUE;
505 			dsl_pool_config_enter(dmu_objset_pool(os), FTAG);
506 		}
507 
508 		err = dsl_prop_register(ds,
509 		    zfs_prop_to_name(ZFS_PROP_PRIMARYCACHE),
510 		    primary_cache_changed_cb, os);
511 		if (err == 0) {
512 			err = dsl_prop_register(ds,
513 			    zfs_prop_to_name(ZFS_PROP_SECONDARYCACHE),
514 			    secondary_cache_changed_cb, os);
515 		}
516 		if (!ds->ds_is_snapshot) {
517 			if (err == 0) {
518 				err = dsl_prop_register(ds,
519 				    zfs_prop_to_name(ZFS_PROP_CHECKSUM),
520 				    checksum_changed_cb, os);
521 			}
522 			if (err == 0) {
523 				err = dsl_prop_register(ds,
524 				    zfs_prop_to_name(ZFS_PROP_COMPRESSION),
525 				    compression_changed_cb, os);
526 			}
527 			if (err == 0) {
528 				err = dsl_prop_register(ds,
529 				    zfs_prop_to_name(ZFS_PROP_COPIES),
530 				    copies_changed_cb, os);
531 			}
532 			if (err == 0) {
533 				err = dsl_prop_register(ds,
534 				    zfs_prop_to_name(ZFS_PROP_DEDUP),
535 				    dedup_changed_cb, os);
536 			}
537 			if (err == 0) {
538 				err = dsl_prop_register(ds,
539 				    zfs_prop_to_name(ZFS_PROP_LOGBIAS),
540 				    logbias_changed_cb, os);
541 			}
542 			if (err == 0) {
543 				err = dsl_prop_register(ds,
544 				    zfs_prop_to_name(ZFS_PROP_SYNC),
545 				    sync_changed_cb, os);
546 			}
547 			if (err == 0) {
548 				err = dsl_prop_register(ds,
549 				    zfs_prop_to_name(
550 				    ZFS_PROP_REDUNDANT_METADATA),
551 				    redundant_metadata_changed_cb, os);
552 			}
553 			if (err == 0) {
554 				err = dsl_prop_register(ds,
555 				    zfs_prop_to_name(ZFS_PROP_RECORDSIZE),
556 				    recordsize_changed_cb, os);
557 			}
558 			if (err == 0) {
559 				err = dsl_prop_register(ds,
560 				    zfs_prop_to_name(ZFS_PROP_DNODESIZE),
561 				    dnodesize_changed_cb, os);
562 			}
563 			if (err == 0) {
564 				err = dsl_prop_register(ds,
565 				    zfs_prop_to_name(
566 				    ZFS_PROP_SPECIAL_SMALL_BLOCKS),
567 				    smallblk_changed_cb, os);
568 			}
569 		}
570 		if (needlock)
571 			dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
572 		if (err != 0) {
573 			arc_buf_destroy(os->os_phys_buf, &os->os_phys_buf);
574 			kmem_free(os, sizeof (objset_t));
575 			return (err);
576 		}
577 	} else {
578 		/* It's the meta-objset. */
579 		os->os_checksum = ZIO_CHECKSUM_FLETCHER_4;
580 		os->os_compress = ZIO_COMPRESS_ON;
581 		os->os_encrypted = B_FALSE;
582 		os->os_copies = spa_max_replication(spa);
583 		os->os_dedup_checksum = ZIO_CHECKSUM_OFF;
584 		os->os_dedup_verify = B_FALSE;
585 		os->os_logbias = ZFS_LOGBIAS_LATENCY;
586 		os->os_sync = ZFS_SYNC_STANDARD;
587 		os->os_primary_cache = ZFS_CACHE_ALL;
588 		os->os_secondary_cache = ZFS_CACHE_ALL;
589 		os->os_dnodesize = DNODE_MIN_SIZE;
590 	}
591 	/*
592 	 * These properties will be filled in by the logic in zfs_get_zplprop()
593 	 * when they are queried for the first time.
594 	 */
595 	os->os_version = OBJSET_PROP_UNINITIALIZED;
596 	os->os_normalization = OBJSET_PROP_UNINITIALIZED;
597 	os->os_utf8only = OBJSET_PROP_UNINITIALIZED;
598 	os->os_casesensitivity = OBJSET_PROP_UNINITIALIZED;
599 
600 	if (ds == NULL || !ds->ds_is_snapshot)
601 		os->os_zil_header = os->os_phys->os_zil_header;
602 	os->os_zil = zil_alloc(os, &os->os_zil_header);
603 
604 	for (i = 0; i < TXG_SIZE; i++) {
605 		os->os_dirty_dnodes[i] = multilist_create(sizeof (dnode_t),
606 		    offsetof(dnode_t, dn_dirty_link[i]),
607 		    dnode_multilist_index_func);
608 	}
609 	list_create(&os->os_dnodes, sizeof (dnode_t),
610 	    offsetof(dnode_t, dn_link));
611 	list_create(&os->os_downgraded_dbufs, sizeof (dmu_buf_impl_t),
612 	    offsetof(dmu_buf_impl_t, db_link));
613 
614 	mutex_init(&os->os_lock, NULL, MUTEX_DEFAULT, NULL);
615 	mutex_init(&os->os_userused_lock, NULL, MUTEX_DEFAULT, NULL);
616 	mutex_init(&os->os_obj_lock, NULL, MUTEX_DEFAULT, NULL);
617 	mutex_init(&os->os_user_ptr_lock, NULL, MUTEX_DEFAULT, NULL);
618 	os->os_obj_next_percpu_len = boot_ncpus;
619 	os->os_obj_next_percpu = kmem_zalloc(os->os_obj_next_percpu_len *
620 	    sizeof (os->os_obj_next_percpu[0]), KM_SLEEP);
621 
622 	dnode_special_open(os, &os->os_phys->os_meta_dnode,
623 	    DMU_META_DNODE_OBJECT, &os->os_meta_dnode);
624 	if (OBJSET_BUF_HAS_USERUSED(os->os_phys_buf)) {
625 		dnode_special_open(os, &os->os_phys->os_userused_dnode,
626 		    DMU_USERUSED_OBJECT, &os->os_userused_dnode);
627 		dnode_special_open(os, &os->os_phys->os_groupused_dnode,
628 		    DMU_GROUPUSED_OBJECT, &os->os_groupused_dnode);
629 		if (OBJSET_BUF_HAS_PROJECTUSED(os->os_phys_buf))
630 			dnode_special_open(os,
631 			    &os->os_phys->os_projectused_dnode,
632 			    DMU_PROJECTUSED_OBJECT, &os->os_projectused_dnode);
633 	}
634 
635 	mutex_init(&os->os_upgrade_lock, NULL, MUTEX_DEFAULT, NULL);
636 
637 	*osp = os;
638 	return (0);
639 }
640 
641 int
642 dmu_objset_from_ds(dsl_dataset_t *ds, objset_t **osp)
643 {
644 	int err = 0;
645 
646 	/*
647 	 * We shouldn't be doing anything with dsl_dataset_t's unless the
648 	 * pool_config lock is held, or the dataset is long-held.
649 	 */
650 	ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool) ||
651 	    dsl_dataset_long_held(ds));
652 
653 	mutex_enter(&ds->ds_opening_lock);
654 	if (ds->ds_objset == NULL) {
655 		objset_t *os;
656 		rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
657 		err = dmu_objset_open_impl(dsl_dataset_get_spa(ds),
658 		    ds, dsl_dataset_get_blkptr(ds), &os);
659 		rrw_exit(&ds->ds_bp_rwlock, FTAG);
660 
661 		if (err == 0) {
662 			mutex_enter(&ds->ds_lock);
663 			ASSERT(ds->ds_objset == NULL);
664 			ds->ds_objset = os;
665 			mutex_exit(&ds->ds_lock);
666 		}
667 	}
668 	*osp = ds->ds_objset;
669 	mutex_exit(&ds->ds_opening_lock);
670 	return (err);
671 }
672 
673 /*
674  * Holds the pool while the objset is held.  Therefore only one objset
675  * can be held at a time.
676  */
677 int
678 dmu_objset_hold_flags(const char *name, boolean_t decrypt, void *tag,
679     objset_t **osp)
680 {
681 	dsl_pool_t *dp;
682 	dsl_dataset_t *ds;
683 	int err;
684 	ds_hold_flags_t flags = (decrypt) ? DS_HOLD_FLAG_DECRYPT : 0;
685 
686 	err = dsl_pool_hold(name, tag, &dp);
687 	if (err != 0)
688 		return (err);
689 	err = dsl_dataset_hold_flags(dp, name, flags, tag, &ds);
690 	if (err != 0) {
691 		dsl_pool_rele(dp, tag);
692 		return (err);
693 	}
694 
695 	err = dmu_objset_from_ds(ds, osp);
696 	if (err != 0) {
697 		dsl_dataset_rele(ds, tag);
698 		dsl_pool_rele(dp, tag);
699 	}
700 
701 	return (err);
702 }
703 
704 int
705 dmu_objset_hold(const char *name, void *tag, objset_t **osp)
706 {
707 	return (dmu_objset_hold_flags(name, B_FALSE, tag, osp));
708 }
709 
710 /* ARGSUSED */
711 static int
712 dmu_objset_own_impl(dsl_dataset_t *ds, dmu_objset_type_t type,
713     boolean_t readonly, boolean_t decrypt, void *tag, objset_t **osp)
714 {
715 	int err;
716 
717 	err = dmu_objset_from_ds(ds, osp);
718 	if (err != 0) {
719 		return (err);
720 	} else if (type != DMU_OST_ANY && type != (*osp)->os_phys->os_type) {
721 		return (SET_ERROR(EINVAL));
722 	} else if (!readonly && dsl_dataset_is_snapshot(ds)) {
723 		return (SET_ERROR(EROFS));
724 	} else if (!readonly && decrypt &&
725 	    dsl_dir_incompatible_encryption_version(ds->ds_dir)) {
726 		return (SET_ERROR(EROFS));
727 	}
728 
729 	/* if we are decrypting, we can now check MACs in os->os_phys_buf */
730 	if (decrypt && arc_is_unauthenticated((*osp)->os_phys_buf)) {
731 		zbookmark_phys_t zb;
732 
733 		SET_BOOKMARK(&zb, ds->ds_object, ZB_ROOT_OBJECT,
734 		    ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
735 		err = arc_untransform((*osp)->os_phys_buf, (*osp)->os_spa,
736 		    &zb, B_FALSE);
737 		if (err != 0)
738 			return (err);
739 
740 		ASSERT0(arc_is_unauthenticated((*osp)->os_phys_buf));
741 	}
742 
743 	return (0);
744 }
745 
746 /*
747  * dsl_pool must not be held when this is called.
748  * Upon successful return, there will be a longhold on the dataset,
749  * and the dsl_pool will not be held.
750  */
751 int
752 dmu_objset_own(const char *name, dmu_objset_type_t type,
753     boolean_t readonly, boolean_t decrypt, void *tag, objset_t **osp)
754 {
755 	dsl_pool_t *dp;
756 	dsl_dataset_t *ds;
757 	int err;
758 	ds_hold_flags_t flags = (decrypt) ? DS_HOLD_FLAG_DECRYPT : 0;
759 
760 	err = dsl_pool_hold(name, FTAG, &dp);
761 	if (err != 0)
762 		return (err);
763 	err = dsl_dataset_own(dp, name, flags, tag, &ds);
764 	if (err != 0) {
765 		dsl_pool_rele(dp, FTAG);
766 		return (err);
767 	}
768 	err = dmu_objset_own_impl(ds, type, readonly, decrypt, tag, osp);
769 	if (err != 0) {
770 		dsl_dataset_disown(ds, flags, tag);
771 		dsl_pool_rele(dp, FTAG);
772 		return (err);
773 	}
774 
775 	/*
776 	 * User accounting requires the dataset to be decrypted and rw.
777 	 * We also don't begin user accounting during claiming to help
778 	 * speed up pool import times and to keep this txg reserved
779 	 * completely for recovery work.
780 	 */
781 	if ((dmu_objset_userobjspace_upgradable(*osp) ||
782 	    dmu_objset_projectquota_upgradable(*osp)) &&
783 	    !readonly && !dp->dp_spa->spa_claiming &&
784 	    (ds->ds_dir->dd_crypto_obj == 0 || decrypt))
785 		dmu_objset_id_quota_upgrade(*osp);
786 
787 	dsl_pool_rele(dp, FTAG);
788 	return (0);
789 }
790 
791 int
792 dmu_objset_own_obj(dsl_pool_t *dp, uint64_t obj, dmu_objset_type_t type,
793     boolean_t readonly, boolean_t decrypt, void *tag, objset_t **osp)
794 {
795 	dsl_dataset_t *ds;
796 	int err;
797 	ds_hold_flags_t flags = (decrypt) ? DS_HOLD_FLAG_DECRYPT : 0;
798 
799 	err = dsl_dataset_own_obj(dp, obj, flags, tag, &ds);
800 	if (err != 0)
801 		return (err);
802 
803 	err = dmu_objset_own_impl(ds, type, readonly, decrypt, tag, osp);
804 	if (err != 0) {
805 		dsl_dataset_disown(ds, flags, tag);
806 		return (err);
807 	}
808 
809 	return (0);
810 }
811 
812 void
813 dmu_objset_rele_flags(objset_t *os, boolean_t decrypt, void *tag)
814 {
815 	ds_hold_flags_t flags = (decrypt) ? DS_HOLD_FLAG_DECRYPT : 0;
816 
817 	dsl_pool_t *dp = dmu_objset_pool(os);
818 	dsl_dataset_rele_flags(os->os_dsl_dataset, flags, tag);
819 	dsl_pool_rele(dp, tag);
820 }
821 
822 void
823 dmu_objset_rele(objset_t *os, void *tag)
824 {
825 	dmu_objset_rele_flags(os, B_FALSE, tag);
826 }
827 
828 /*
829  * When we are called, os MUST refer to an objset associated with a dataset
830  * that is owned by 'tag'; that is, is held and long held by 'tag' and ds_owner
831  * == tag.  We will then release and reacquire ownership of the dataset while
832  * holding the pool config_rwlock to avoid intervening namespace or ownership
833  * changes may occur.
834  *
835  * This exists solely to accommodate zfs_ioc_userspace_upgrade()'s desire to
836  * release the hold on its dataset and acquire a new one on the dataset of the
837  * same name so that it can be partially torn down and reconstructed.
838  */
839 void
840 dmu_objset_refresh_ownership(dsl_dataset_t *ds, dsl_dataset_t **newds,
841     boolean_t decrypt, void *tag)
842 {
843 	dsl_pool_t *dp;
844 	char name[ZFS_MAX_DATASET_NAME_LEN];
845 
846 	VERIFY3P(ds, !=, NULL);
847 	VERIFY3P(ds->ds_owner, ==, tag);
848 	VERIFY(dsl_dataset_long_held(ds));
849 
850 	dsl_dataset_name(ds, name);
851 	dp = ds->ds_dir->dd_pool;
852 	dsl_pool_config_enter(dp, FTAG);
853 
854 	dsl_dataset_disown(ds, 0, tag);
855 	VERIFY0(dsl_dataset_own(dp, name,
856 	    (decrypt) ? DS_HOLD_FLAG_DECRYPT : 0, tag, newds));
857 	dsl_pool_config_exit(dp, FTAG);
858 }
859 
860 void
861 dmu_objset_disown(objset_t *os, boolean_t decrypt, void *tag)
862 {
863 	/*
864 	 * Stop upgrading thread
865 	 */
866 	dmu_objset_upgrade_stop(os);
867 	dsl_dataset_disown(os->os_dsl_dataset,
868 	    (decrypt) ? DS_HOLD_FLAG_DECRYPT : 0, tag);
869 }
870 
871 void
872 dmu_objset_evict_dbufs(objset_t *os)
873 {
874 	dnode_t dn_marker;
875 	dnode_t *dn;
876 
877 	mutex_enter(&os->os_lock);
878 	dn = list_head(&os->os_dnodes);
879 	while (dn != NULL) {
880 		/*
881 		 * Skip dnodes without holds.  We have to do this dance
882 		 * because dnode_add_ref() only works if there is already a
883 		 * hold.  If the dnode has no holds, then it has no dbufs.
884 		 */
885 		if (dnode_add_ref(dn, FTAG)) {
886 			list_insert_after(&os->os_dnodes, dn, &dn_marker);
887 			mutex_exit(&os->os_lock);
888 
889 			dnode_evict_dbufs(dn);
890 			dnode_rele(dn, FTAG);
891 
892 			mutex_enter(&os->os_lock);
893 			dn = list_next(&os->os_dnodes, &dn_marker);
894 			list_remove(&os->os_dnodes, &dn_marker);
895 		} else {
896 			dn = list_next(&os->os_dnodes, dn);
897 		}
898 	}
899 	mutex_exit(&os->os_lock);
900 
901 	if (DMU_USERUSED_DNODE(os) != NULL) {
902 		if (DMU_PROJECTUSED_DNODE(os) != NULL)
903 			dnode_evict_dbufs(DMU_PROJECTUSED_DNODE(os));
904 		dnode_evict_dbufs(DMU_GROUPUSED_DNODE(os));
905 		dnode_evict_dbufs(DMU_USERUSED_DNODE(os));
906 	}
907 	dnode_evict_dbufs(DMU_META_DNODE(os));
908 }
909 
910 /*
911  * Objset eviction processing is split into into two pieces.
912  * The first marks the objset as evicting, evicts any dbufs that
913  * have a refcount of zero, and then queues up the objset for the
914  * second phase of eviction.  Once os->os_dnodes has been cleared by
915  * dnode_buf_pageout()->dnode_destroy(), the second phase is executed.
916  * The second phase closes the special dnodes, dequeues the objset from
917  * the list of those undergoing eviction, and finally frees the objset.
918  *
919  * NOTE: Due to asynchronous eviction processing (invocation of
920  *       dnode_buf_pageout()), it is possible for the meta dnode for the
921  *       objset to have no holds even though os->os_dnodes is not empty.
922  */
923 void
924 dmu_objset_evict(objset_t *os)
925 {
926 	dsl_dataset_t *ds = os->os_dsl_dataset;
927 
928 	for (int t = 0; t < TXG_SIZE; t++)
929 		ASSERT(!dmu_objset_is_dirty(os, t));
930 
931 	if (ds)
932 		dsl_prop_unregister_all(ds, os);
933 
934 	if (os->os_sa)
935 		sa_tear_down(os);
936 
937 	dmu_objset_evict_dbufs(os);
938 
939 	mutex_enter(&os->os_lock);
940 	spa_evicting_os_register(os->os_spa, os);
941 	if (list_is_empty(&os->os_dnodes)) {
942 		mutex_exit(&os->os_lock);
943 		dmu_objset_evict_done(os);
944 	} else {
945 		mutex_exit(&os->os_lock);
946 	}
947 
948 
949 }
950 
951 void
952 dmu_objset_evict_done(objset_t *os)
953 {
954 	ASSERT3P(list_head(&os->os_dnodes), ==, NULL);
955 
956 	dnode_special_close(&os->os_meta_dnode);
957 	if (DMU_USERUSED_DNODE(os)) {
958 		if (DMU_PROJECTUSED_DNODE(os))
959 			dnode_special_close(&os->os_projectused_dnode);
960 		dnode_special_close(&os->os_userused_dnode);
961 		dnode_special_close(&os->os_groupused_dnode);
962 	}
963 	zil_free(os->os_zil);
964 
965 	arc_buf_destroy(os->os_phys_buf, &os->os_phys_buf);
966 
967 	/*
968 	 * This is a barrier to prevent the objset from going away in
969 	 * dnode_move() until we can safely ensure that the objset is still in
970 	 * use. We consider the objset valid before the barrier and invalid
971 	 * after the barrier.
972 	 */
973 	rw_enter(&os_lock, RW_READER);
974 	rw_exit(&os_lock);
975 
976 	kmem_free(os->os_obj_next_percpu,
977 	    os->os_obj_next_percpu_len * sizeof (os->os_obj_next_percpu[0]));
978 
979 	mutex_destroy(&os->os_lock);
980 	mutex_destroy(&os->os_userused_lock);
981 	mutex_destroy(&os->os_obj_lock);
982 	mutex_destroy(&os->os_user_ptr_lock);
983 	for (int i = 0; i < TXG_SIZE; i++) {
984 		multilist_destroy(os->os_dirty_dnodes[i]);
985 	}
986 	spa_evicting_os_deregister(os->os_spa, os);
987 	kmem_free(os, sizeof (objset_t));
988 }
989 
990 timestruc_t
991 dmu_objset_snap_cmtime(objset_t *os)
992 {
993 	return (dsl_dir_snap_cmtime(os->os_dsl_dataset->ds_dir));
994 }
995 
996 /* ARGSUSED */
997 objset_t *
998 dmu_objset_create_impl_dnstats(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
999     dmu_objset_type_t type, int levels, int blksz, int ibs, dmu_tx_t *tx)
1000 {
1001 	objset_t *os;
1002 	dnode_t *mdn;
1003 
1004 	ASSERT(dmu_tx_is_syncing(tx));
1005 
1006 	if (blksz == 0)
1007 		blksz = 1 << DNODE_BLOCK_SHIFT;
1008 	if (ibs == 0)
1009 		ibs = DN_MAX_INDBLKSHIFT;
1010 
1011 	if (ds != NULL)
1012 		VERIFY0(dmu_objset_from_ds(ds, &os));
1013 	else
1014 		VERIFY0(dmu_objset_open_impl(spa, NULL, bp, &os));
1015 
1016 	mdn = DMU_META_DNODE(os);
1017 
1018 	dnode_allocate(mdn, DMU_OT_DNODE, DNODE_BLOCK_SIZE, DN_MAX_INDBLKSHIFT,
1019 	    DMU_OT_NONE, 0, DNODE_MIN_SLOTS, tx);
1020 
1021 	/*
1022 	 * We don't want to have to increase the meta-dnode's nlevels
1023 	 * later, because then we could do it in quescing context while
1024 	 * we are also accessing it in open context.
1025 	 *
1026 	 * This precaution is not necessary for the MOS (ds == NULL),
1027 	 * because the MOS is only updated in syncing context.
1028 	 * This is most fortunate: the MOS is the only objset that
1029 	 * needs to be synced multiple times as spa_sync() iterates
1030 	 * to convergence, so minimizing its dn_nlevels matters.
1031 	 */
1032 	if (ds != NULL) {
1033 		if (levels == 0) {
1034 			levels = 1;
1035 
1036 			/*
1037 			 * Determine the number of levels necessary for the
1038 			 * meta-dnode to contain DN_MAX_OBJECT dnodes.  Note
1039 			 * that in order to ensure that we do not overflow
1040 			 * 64 bits, there has to be a nlevels that gives us a
1041 			 * number of blocks > DN_MAX_OBJECT but < 2^64.
1042 			 * Therefore, (mdn->dn_indblkshift - SPA_BLKPTRSHIFT)
1043 			 * (10) must be less than (64 - log2(DN_MAX_OBJECT))
1044 			 * (16).
1045 			 */
1046 			while ((uint64_t)mdn->dn_nblkptr <<
1047 			    (mdn->dn_datablkshift - DNODE_SHIFT + (levels - 1) *
1048 			    (mdn->dn_indblkshift - SPA_BLKPTRSHIFT)) <
1049 			    DN_MAX_OBJECT)
1050 				levels++;
1051 		}
1052 
1053 		mdn->dn_next_nlevels[tx->tx_txg & TXG_MASK] =
1054 		    mdn->dn_nlevels = levels;
1055 	}
1056 
1057 	ASSERT(type != DMU_OST_NONE);
1058 	ASSERT(type != DMU_OST_ANY);
1059 	ASSERT(type < DMU_OST_NUMTYPES);
1060 	os->os_phys->os_type = type;
1061 
1062 	/*
1063 	 * Enable user accounting if it is enabled and this is not an
1064 	 * encrypted receive.
1065 	 */
1066 	if (dmu_objset_userused_enabled(os) &&
1067 	    (!os->os_encrypted || !dmu_objset_is_receiving(os))) {
1068 		os->os_phys->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
1069 		if (dmu_objset_userobjused_enabled(os)) {
1070 			ds->ds_feature_activation_needed[
1071 			    SPA_FEATURE_USEROBJ_ACCOUNTING] = B_TRUE;
1072 			os->os_phys->os_flags |=
1073 			    OBJSET_FLAG_USEROBJACCOUNTING_COMPLETE;
1074 		}
1075 		if (dmu_objset_projectquota_enabled(os)) {
1076 			ds->ds_feature_activation_needed[
1077 			    SPA_FEATURE_PROJECT_QUOTA] = B_TRUE;
1078 			os->os_phys->os_flags |=
1079 			    OBJSET_FLAG_PROJECTQUOTA_COMPLETE;
1080 		}
1081 		os->os_flags = os->os_phys->os_flags;
1082 	}
1083 
1084 	dsl_dataset_dirty(ds, tx);
1085 
1086 	return (os);
1087 }
1088 
1089 /* called from dsl for meta-objset */
1090 objset_t *
1091 dmu_objset_create_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
1092     dmu_objset_type_t type, dmu_tx_t *tx)
1093 {
1094 	return (dmu_objset_create_impl_dnstats(spa, ds, bp, type, 0, 0, 0, tx));
1095 }
1096 
1097 typedef struct dmu_objset_create_arg {
1098 	const char *doca_name;
1099 	cred_t *doca_cred;
1100 	void (*doca_userfunc)(objset_t *os, void *arg,
1101 	    cred_t *cr, dmu_tx_t *tx);
1102 	void *doca_userarg;
1103 	dmu_objset_type_t doca_type;
1104 	uint64_t doca_flags;
1105 	dsl_crypto_params_t *doca_dcp;
1106 } dmu_objset_create_arg_t;
1107 
1108 /*ARGSUSED*/
1109 static int
1110 dmu_objset_create_check(void *arg, dmu_tx_t *tx)
1111 {
1112 	dmu_objset_create_arg_t *doca = arg;
1113 	dsl_pool_t *dp = dmu_tx_pool(tx);
1114 	dsl_dir_t *pdd;
1115 	const char *tail;
1116 	int error;
1117 
1118 	if (strchr(doca->doca_name, '@') != NULL)
1119 		return (SET_ERROR(EINVAL));
1120 
1121 	if (strlen(doca->doca_name) >= ZFS_MAX_DATASET_NAME_LEN)
1122 		return (SET_ERROR(ENAMETOOLONG));
1123 
1124 	if (dataset_nestcheck(doca->doca_name) != 0)
1125 		return (SET_ERROR(ENAMETOOLONG));
1126 
1127 	error = dsl_dir_hold(dp, doca->doca_name, FTAG, &pdd, &tail);
1128 	if (error != 0)
1129 		return (error);
1130 	if (tail == NULL) {
1131 		dsl_dir_rele(pdd, FTAG);
1132 		return (SET_ERROR(EEXIST));
1133 	}
1134 
1135 	error = dmu_objset_create_crypt_check(pdd, doca->doca_dcp, NULL);
1136 	if (error != 0) {
1137 		dsl_dir_rele(pdd, FTAG);
1138 		return (error);
1139 	}
1140 
1141 	error = dsl_fs_ss_limit_check(pdd, 1, ZFS_PROP_FILESYSTEM_LIMIT, NULL,
1142 	    doca->doca_cred);
1143 
1144 	dsl_dir_rele(pdd, FTAG);
1145 
1146 	return (error);
1147 }
1148 
1149 static void
1150 dmu_objset_create_sync(void *arg, dmu_tx_t *tx)
1151 {
1152 	dmu_objset_create_arg_t *doca = arg;
1153 	dsl_pool_t *dp = dmu_tx_pool(tx);
1154 	spa_t *spa = dp->dp_spa;
1155 	dsl_dir_t *pdd;
1156 	const char *tail;
1157 	dsl_dataset_t *ds;
1158 	uint64_t obj;
1159 	blkptr_t *bp;
1160 	objset_t *os;
1161 	zio_t *rzio;
1162 
1163 	VERIFY0(dsl_dir_hold(dp, doca->doca_name, FTAG, &pdd, &tail));
1164 
1165 	obj = dsl_dataset_create_sync(pdd, tail, NULL, doca->doca_flags,
1166 	    doca->doca_cred, doca->doca_dcp, tx);
1167 
1168 	VERIFY0(dsl_dataset_hold_obj_flags(pdd->dd_pool, obj,
1169 	    DS_HOLD_FLAG_DECRYPT, FTAG, &ds));
1170 	rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
1171 	bp = dsl_dataset_get_blkptr(ds);
1172 	os = dmu_objset_create_impl(spa, ds, bp, doca->doca_type, tx);
1173 	rrw_exit(&ds->ds_bp_rwlock, FTAG);
1174 
1175 	if (doca->doca_userfunc != NULL) {
1176 		doca->doca_userfunc(os, doca->doca_userarg,
1177 		    doca->doca_cred, tx);
1178 	}
1179 
1180 	/*
1181 	 * The doca_userfunc() may write out some data that needs to be
1182 	 * encrypted if the dataset is encrypted (specifically the root
1183 	 * directory).  This data must be written out before the encryption
1184 	 * key mapping is removed by dsl_dataset_rele_flags().  Force the
1185 	 * I/O to occur immediately by invoking the relevant sections of
1186 	 * dsl_pool_sync().
1187 	 */
1188 	if (os->os_encrypted) {
1189 		dsl_dataset_t *tmpds = NULL;
1190 		boolean_t need_sync_done = B_FALSE;
1191 
1192 		mutex_enter(&ds->ds_lock);
1193 		ds->ds_owner = FTAG;
1194 		mutex_exit(&ds->ds_lock);
1195 
1196 		rzio = zio_root(spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
1197 		tmpds = txg_list_remove_this(&dp->dp_dirty_datasets, ds,
1198 		    tx->tx_txg);
1199 		if (tmpds != NULL) {
1200 			dsl_dataset_sync(ds, rzio, tx);
1201 			need_sync_done = B_TRUE;
1202 		}
1203 		VERIFY0(zio_wait(rzio));
1204 		dmu_objset_do_userquota_updates(os, tx);
1205 		taskq_wait(dp->dp_sync_taskq);
1206 		if (txg_list_member(&dp->dp_dirty_datasets, ds, tx->tx_txg)) {
1207 			ASSERT3P(ds->ds_key_mapping, !=, NULL);
1208 			key_mapping_rele(spa, ds->ds_key_mapping, ds);
1209 		}
1210 
1211 		rzio = zio_root(spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
1212 		tmpds = txg_list_remove_this(&dp->dp_dirty_datasets, ds,
1213 		    tx->tx_txg);
1214 		if (tmpds != NULL) {
1215 			dmu_buf_rele(ds->ds_dbuf, ds);
1216 			dsl_dataset_sync(ds, rzio, tx);
1217 		}
1218 		VERIFY0(zio_wait(rzio));
1219 
1220 		if (need_sync_done) {
1221 			ASSERT3P(ds->ds_key_mapping, !=, NULL);
1222 			key_mapping_rele(spa, ds->ds_key_mapping, ds);
1223 			dsl_dataset_sync_done(ds, tx);
1224 		}
1225 
1226 		mutex_enter(&ds->ds_lock);
1227 		ds->ds_owner = NULL;
1228 		mutex_exit(&ds->ds_lock);
1229 	}
1230 
1231 	spa_history_log_internal_ds(ds, "create", tx, "");
1232 	dsl_dataset_rele_flags(ds, DS_HOLD_FLAG_DECRYPT, FTAG);
1233 	dsl_dir_rele(pdd, FTAG);
1234 }
1235 
1236 int
1237 dmu_objset_create(const char *name, dmu_objset_type_t type, uint64_t flags,
1238     dsl_crypto_params_t *dcp, dmu_objset_create_sync_func_t func, void *arg)
1239 {
1240 	dmu_objset_create_arg_t doca;
1241 	dsl_crypto_params_t tmp_dcp = { 0 };
1242 
1243 	doca.doca_name = name;
1244 	doca.doca_cred = CRED();
1245 	doca.doca_flags = flags;
1246 	doca.doca_userfunc = func;
1247 	doca.doca_userarg = arg;
1248 	doca.doca_type = type;
1249 
1250 	/*
1251 	 * Some callers (mostly for testing) do not provide a dcp on their
1252 	 * own but various code inside the sync task will require it to be
1253 	 * allocated. Rather than adding NULL checks throughout this code
1254 	 * or adding dummy dcp's to all of the callers we simply create a
1255 	 * dummy one here and use that. This zero dcp will have the same
1256 	 * effect as asking for inheritence of all encryption params.
1257 	 */
1258 	doca.doca_dcp = (dcp != NULL) ? dcp : &tmp_dcp;
1259 
1260 	return (dsl_sync_task(name,
1261 	    dmu_objset_create_check, dmu_objset_create_sync, &doca,
1262 	    6, ZFS_SPACE_CHECK_NORMAL));
1263 }
1264 
1265 typedef struct dmu_objset_clone_arg {
1266 	const char *doca_clone;
1267 	const char *doca_origin;
1268 	cred_t *doca_cred;
1269 } dmu_objset_clone_arg_t;
1270 
1271 /*ARGSUSED*/
1272 static int
1273 dmu_objset_clone_check(void *arg, dmu_tx_t *tx)
1274 {
1275 	dmu_objset_clone_arg_t *doca = arg;
1276 	dsl_dir_t *pdd;
1277 	const char *tail;
1278 	int error;
1279 	dsl_dataset_t *origin;
1280 	dsl_pool_t *dp = dmu_tx_pool(tx);
1281 
1282 	if (strchr(doca->doca_clone, '@') != NULL)
1283 		return (SET_ERROR(EINVAL));
1284 
1285 	if (strlen(doca->doca_clone) >= ZFS_MAX_DATASET_NAME_LEN)
1286 		return (SET_ERROR(ENAMETOOLONG));
1287 
1288 	error = dsl_dir_hold(dp, doca->doca_clone, FTAG, &pdd, &tail);
1289 	if (error != 0)
1290 		return (error);
1291 	if (tail == NULL) {
1292 		dsl_dir_rele(pdd, FTAG);
1293 		return (SET_ERROR(EEXIST));
1294 	}
1295 
1296 	error = dsl_fs_ss_limit_check(pdd, 1, ZFS_PROP_FILESYSTEM_LIMIT, NULL,
1297 	    doca->doca_cred);
1298 	if (error != 0) {
1299 		dsl_dir_rele(pdd, FTAG);
1300 		return (SET_ERROR(EDQUOT));
1301 	}
1302 
1303 	error = dsl_dataset_hold(dp, doca->doca_origin, FTAG, &origin);
1304 	if (error != 0) {
1305 		dsl_dir_rele(pdd, FTAG);
1306 		return (error);
1307 	}
1308 
1309 	/* You can only clone snapshots, not the head datasets. */
1310 	if (!origin->ds_is_snapshot) {
1311 		dsl_dataset_rele(origin, FTAG);
1312 		dsl_dir_rele(pdd, FTAG);
1313 		return (SET_ERROR(EINVAL));
1314 	}
1315 
1316 	dsl_dataset_rele(origin, FTAG);
1317 	dsl_dir_rele(pdd, FTAG);
1318 
1319 	return (0);
1320 }
1321 
1322 static void
1323 dmu_objset_clone_sync(void *arg, dmu_tx_t *tx)
1324 {
1325 	dmu_objset_clone_arg_t *doca = arg;
1326 	dsl_pool_t *dp = dmu_tx_pool(tx);
1327 	dsl_dir_t *pdd;
1328 	const char *tail;
1329 	dsl_dataset_t *origin, *ds;
1330 	uint64_t obj;
1331 	char namebuf[ZFS_MAX_DATASET_NAME_LEN];
1332 
1333 	VERIFY0(dsl_dir_hold(dp, doca->doca_clone, FTAG, &pdd, &tail));
1334 	VERIFY0(dsl_dataset_hold(dp, doca->doca_origin, FTAG, &origin));
1335 
1336 	obj = dsl_dataset_create_sync(pdd, tail, origin, 0,
1337 	    doca->doca_cred, NULL, tx);
1338 
1339 	VERIFY0(dsl_dataset_hold_obj(pdd->dd_pool, obj, FTAG, &ds));
1340 	dsl_dataset_name(origin, namebuf);
1341 	spa_history_log_internal_ds(ds, "clone", tx,
1342 	    "origin=%s (%llu)", namebuf, origin->ds_object);
1343 	dsl_dataset_rele(ds, FTAG);
1344 	dsl_dataset_rele(origin, FTAG);
1345 	dsl_dir_rele(pdd, FTAG);
1346 }
1347 
1348 int
1349 dmu_objset_clone(const char *clone, const char *origin)
1350 {
1351 	dmu_objset_clone_arg_t doca;
1352 
1353 	doca.doca_clone = clone;
1354 	doca.doca_origin = origin;
1355 	doca.doca_cred = CRED();
1356 
1357 	return (dsl_sync_task(clone,
1358 	    dmu_objset_clone_check, dmu_objset_clone_sync, &doca,
1359 	    6, ZFS_SPACE_CHECK_NORMAL));
1360 }
1361 
1362 static int
1363 dmu_objset_remap_indirects_impl(objset_t *os, uint64_t last_removed_txg)
1364 {
1365 	int error = 0;
1366 	uint64_t object = 0;
1367 	while ((error = dmu_object_next(os, &object, B_FALSE, 0)) == 0) {
1368 		error = dmu_object_remap_indirects(os, object,
1369 		    last_removed_txg);
1370 		/*
1371 		 * If the ZPL removed the object before we managed to dnode_hold
1372 		 * it, we would get an ENOENT. If the ZPL declares its intent
1373 		 * to remove the object (dnode_free) before we manage to
1374 		 * dnode_hold it, we would get an EEXIST. In either case, we
1375 		 * want to continue remapping the other objects in the objset;
1376 		 * in all other cases, we want to break early.
1377 		 */
1378 		if (error != 0 && error != ENOENT && error != EEXIST) {
1379 			break;
1380 		}
1381 	}
1382 	if (error == ESRCH) {
1383 		error = 0;
1384 	}
1385 	return (error);
1386 }
1387 
1388 int
1389 dmu_objset_remap_indirects(const char *fsname)
1390 {
1391 	int error = 0;
1392 	objset_t *os = NULL;
1393 	uint64_t last_removed_txg;
1394 	uint64_t remap_start_txg;
1395 	dsl_dir_t *dd;
1396 
1397 	error = dmu_objset_hold(fsname, FTAG, &os);
1398 	if (error != 0) {
1399 		return (error);
1400 	}
1401 	dd = dmu_objset_ds(os)->ds_dir;
1402 
1403 	if (!spa_feature_is_enabled(dmu_objset_spa(os),
1404 	    SPA_FEATURE_OBSOLETE_COUNTS)) {
1405 		dmu_objset_rele(os, FTAG);
1406 		return (SET_ERROR(ENOTSUP));
1407 	}
1408 
1409 	if (dsl_dataset_is_snapshot(dmu_objset_ds(os))) {
1410 		dmu_objset_rele(os, FTAG);
1411 		return (SET_ERROR(EINVAL));
1412 	}
1413 
1414 	/*
1415 	 * If there has not been a removal, we're done.
1416 	 */
1417 	last_removed_txg = spa_get_last_removal_txg(dmu_objset_spa(os));
1418 	if (last_removed_txg == -1ULL) {
1419 		dmu_objset_rele(os, FTAG);
1420 		return (0);
1421 	}
1422 
1423 	/*
1424 	 * If we have remapped since the last removal, we're done.
1425 	 */
1426 	if (dsl_dir_is_zapified(dd)) {
1427 		uint64_t last_remap_txg;
1428 		if (zap_lookup(spa_meta_objset(dmu_objset_spa(os)),
1429 		    dd->dd_object, DD_FIELD_LAST_REMAP_TXG,
1430 		    sizeof (last_remap_txg), 1, &last_remap_txg) == 0 &&
1431 		    last_remap_txg > last_removed_txg) {
1432 			dmu_objset_rele(os, FTAG);
1433 			return (0);
1434 		}
1435 	}
1436 
1437 	dsl_dataset_long_hold(dmu_objset_ds(os), FTAG);
1438 	dsl_pool_rele(dmu_objset_pool(os), FTAG);
1439 
1440 	remap_start_txg = spa_last_synced_txg(dmu_objset_spa(os));
1441 	error = dmu_objset_remap_indirects_impl(os, last_removed_txg);
1442 	if (error == 0) {
1443 		/*
1444 		 * We update the last_remap_txg to be the start txg so that
1445 		 * we can guarantee that every block older than last_remap_txg
1446 		 * that can be remapped has been remapped.
1447 		 */
1448 		error = dsl_dir_update_last_remap_txg(dd, remap_start_txg);
1449 	}
1450 
1451 	dsl_dataset_long_rele(dmu_objset_ds(os), FTAG);
1452 	dsl_dataset_rele(dmu_objset_ds(os), FTAG);
1453 
1454 	return (error);
1455 }
1456 
1457 int
1458 dmu_objset_snapshot_one(const char *fsname, const char *snapname)
1459 {
1460 	int err;
1461 	char *longsnap = kmem_asprintf("%s@%s", fsname, snapname);
1462 	nvlist_t *snaps = fnvlist_alloc();
1463 
1464 	fnvlist_add_boolean(snaps, longsnap);
1465 	strfree(longsnap);
1466 	err = dsl_dataset_snapshot(snaps, NULL, NULL);
1467 	fnvlist_free(snaps);
1468 	return (err);
1469 }
1470 
1471 static void
1472 dmu_objset_upgrade_task_cb(void *data)
1473 {
1474 	objset_t *os = data;
1475 
1476 	mutex_enter(&os->os_upgrade_lock);
1477 	os->os_upgrade_status = EINTR;
1478 	if (!os->os_upgrade_exit) {
1479 		mutex_exit(&os->os_upgrade_lock);
1480 
1481 		os->os_upgrade_status = os->os_upgrade_cb(os);
1482 		mutex_enter(&os->os_upgrade_lock);
1483 	}
1484 	os->os_upgrade_exit = B_TRUE;
1485 	os->os_upgrade_id = 0;
1486 	mutex_exit(&os->os_upgrade_lock);
1487 }
1488 
1489 static void
1490 dmu_objset_upgrade(objset_t *os, dmu_objset_upgrade_cb_t cb)
1491 {
1492 	if (os->os_upgrade_id != 0)
1493 		return;
1494 
1495 	mutex_enter(&os->os_upgrade_lock);
1496 	if (os->os_upgrade_id == 0 && os->os_upgrade_status == 0) {
1497 		os->os_upgrade_exit = B_FALSE;
1498 		os->os_upgrade_cb = cb;
1499 		os->os_upgrade_id = taskq_dispatch(
1500 		    os->os_spa->spa_upgrade_taskq,
1501 		    dmu_objset_upgrade_task_cb, os, TQ_SLEEP);
1502 		if (os->os_upgrade_id == 0)
1503 			os->os_upgrade_status = ENOMEM;
1504 	}
1505 	mutex_exit(&os->os_upgrade_lock);
1506 }
1507 
1508 static void
1509 dmu_objset_upgrade_stop(objset_t *os)
1510 {
1511 	mutex_enter(&os->os_upgrade_lock);
1512 	os->os_upgrade_exit = B_TRUE;
1513 	if (os->os_upgrade_id != 0) {
1514 		os->os_upgrade_id = 0;
1515 		mutex_exit(&os->os_upgrade_lock);
1516 
1517 		taskq_wait(os->os_spa->spa_upgrade_taskq);
1518 	} else {
1519 		mutex_exit(&os->os_upgrade_lock);
1520 	}
1521 }
1522 
1523 static void
1524 dmu_objset_sync_dnodes(multilist_sublist_t *list, dmu_tx_t *tx)
1525 {
1526 	dnode_t *dn;
1527 
1528 	while ((dn = multilist_sublist_head(list)) != NULL) {
1529 		ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
1530 		ASSERT(dn->dn_dbuf->db_data_pending);
1531 		/*
1532 		 * Initialize dn_zio outside dnode_sync() because the
1533 		 * meta-dnode needs to set it outside dnode_sync().
1534 		 */
1535 		dn->dn_zio = dn->dn_dbuf->db_data_pending->dr_zio;
1536 		ASSERT(dn->dn_zio);
1537 
1538 		ASSERT3U(dn->dn_nlevels, <=, DN_MAX_LEVELS);
1539 		multilist_sublist_remove(list, dn);
1540 
1541 		/*
1542 		 * If we are not doing useraccounting (os_synced_dnodes == NULL)
1543 		 * we are done with this dnode for this txg. Unset dn_dirty_txg
1544 		 * if later txgs aren't dirtying it so that future holders do
1545 		 * not get a stale value. Otherwise, we will do this in
1546 		 * userquota_updates_task() when processing has completely
1547 		 * finished for this txg.
1548 		 */
1549 		multilist_t *newlist = dn->dn_objset->os_synced_dnodes;
1550 		if (newlist != NULL) {
1551 			(void) dnode_add_ref(dn, newlist);
1552 			multilist_insert(newlist, dn);
1553 		} else {
1554 			mutex_enter(&dn->dn_mtx);
1555 			if (dn->dn_dirty_txg == tx->tx_txg)
1556 				dn->dn_dirty_txg = 0;
1557 			mutex_exit(&dn->dn_mtx);
1558 		}
1559 
1560 		dnode_sync(dn, tx);
1561 	}
1562 }
1563 
1564 /* ARGSUSED */
1565 static void
1566 dmu_objset_write_ready(zio_t *zio, arc_buf_t *abuf, void *arg)
1567 {
1568 	blkptr_t *bp = zio->io_bp;
1569 	objset_t *os = arg;
1570 	dnode_phys_t *dnp = &os->os_phys->os_meta_dnode;
1571 	uint64_t fill = 0;
1572 
1573 	ASSERT(!BP_IS_EMBEDDED(bp));
1574 	ASSERT3U(BP_GET_TYPE(bp), ==, DMU_OT_OBJSET);
1575 
1576 	/*
1577 	 * Update rootbp fill count: it should be the number of objects
1578 	 * allocated in the object set (not counting the "special"
1579 	 * objects that are stored in the objset_phys_t -- the meta
1580 	 * dnode and user/group/project accounting objects).
1581 	 */
1582 	for (int i = 0; i < dnp->dn_nblkptr; i++)
1583 		fill += BP_GET_FILL(&dnp->dn_blkptr[i]);
1584 
1585 	BP_SET_FILL(bp, fill);
1586 
1587 	if (os->os_dsl_dataset != NULL)
1588 		rrw_enter(&os->os_dsl_dataset->ds_bp_rwlock, RW_WRITER, FTAG);
1589 	*os->os_rootbp = *bp;
1590 	if (os->os_dsl_dataset != NULL)
1591 		rrw_exit(&os->os_dsl_dataset->ds_bp_rwlock, FTAG);
1592 }
1593 
1594 /* ARGSUSED */
1595 static void
1596 dmu_objset_write_done(zio_t *zio, arc_buf_t *abuf, void *arg)
1597 {
1598 	blkptr_t *bp = zio->io_bp;
1599 	blkptr_t *bp_orig = &zio->io_bp_orig;
1600 	objset_t *os = arg;
1601 
1602 	if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
1603 		ASSERT(BP_EQUAL(bp, bp_orig));
1604 	} else {
1605 		dsl_dataset_t *ds = os->os_dsl_dataset;
1606 		dmu_tx_t *tx = os->os_synctx;
1607 
1608 		(void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
1609 		dsl_dataset_block_born(ds, bp, tx);
1610 	}
1611 	kmem_free(bp, sizeof (*bp));
1612 }
1613 
1614 typedef struct sync_dnodes_arg {
1615 	multilist_t *sda_list;
1616 	int sda_sublist_idx;
1617 	multilist_t *sda_newlist;
1618 	dmu_tx_t *sda_tx;
1619 } sync_dnodes_arg_t;
1620 
1621 static void
1622 sync_dnodes_task(void *arg)
1623 {
1624 	sync_dnodes_arg_t *sda = arg;
1625 
1626 	multilist_sublist_t *ms =
1627 	    multilist_sublist_lock(sda->sda_list, sda->sda_sublist_idx);
1628 
1629 	dmu_objset_sync_dnodes(ms, sda->sda_tx);
1630 
1631 	multilist_sublist_unlock(ms);
1632 
1633 	kmem_free(sda, sizeof (*sda));
1634 }
1635 
1636 
1637 /* called from dsl */
1638 void
1639 dmu_objset_sync(objset_t *os, zio_t *pio, dmu_tx_t *tx)
1640 {
1641 	int txgoff;
1642 	zbookmark_phys_t zb;
1643 	zio_prop_t zp;
1644 	zio_t *zio;
1645 	list_t *list;
1646 	dbuf_dirty_record_t *dr;
1647 	blkptr_t *blkptr_copy = kmem_alloc(sizeof (*os->os_rootbp), KM_SLEEP);
1648 	*blkptr_copy = *os->os_rootbp;
1649 
1650 	dprintf_ds(os->os_dsl_dataset, "txg=%llu\n", tx->tx_txg);
1651 
1652 	ASSERT(dmu_tx_is_syncing(tx));
1653 	/* XXX the write_done callback should really give us the tx... */
1654 	os->os_synctx = tx;
1655 
1656 	if (os->os_dsl_dataset == NULL) {
1657 		/*
1658 		 * This is the MOS.  If we have upgraded,
1659 		 * spa_max_replication() could change, so reset
1660 		 * os_copies here.
1661 		 */
1662 		os->os_copies = spa_max_replication(os->os_spa);
1663 	}
1664 
1665 	/*
1666 	 * Create the root block IO
1667 	 */
1668 	SET_BOOKMARK(&zb, os->os_dsl_dataset ?
1669 	    os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
1670 	    ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
1671 	arc_release(os->os_phys_buf, &os->os_phys_buf);
1672 
1673 	dmu_write_policy(os, NULL, 0, 0, &zp);
1674 
1675 	/*
1676 	 * If we are either claiming the ZIL or doing a raw receive, write
1677 	 * out the os_phys_buf raw. Neither of these actions will effect the
1678 	 * MAC at this point.
1679 	 */
1680 	if (os->os_raw_receive ||
1681 	    os->os_next_write_raw[tx->tx_txg & TXG_MASK]) {
1682 		ASSERT(os->os_encrypted);
1683 		arc_convert_to_raw(os->os_phys_buf,
1684 		    os->os_dsl_dataset->ds_object, ZFS_HOST_BYTEORDER,
1685 		    DMU_OT_OBJSET, NULL, NULL, NULL);
1686 	}
1687 
1688 	zio = arc_write(pio, os->os_spa, tx->tx_txg,
1689 	    blkptr_copy, os->os_phys_buf, DMU_OS_IS_L2CACHEABLE(os),
1690 	    &zp, dmu_objset_write_ready, NULL, NULL, dmu_objset_write_done,
1691 	    os, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
1692 
1693 	/*
1694 	 * Sync special dnodes - the parent IO for the sync is the root block
1695 	 */
1696 	DMU_META_DNODE(os)->dn_zio = zio;
1697 	dnode_sync(DMU_META_DNODE(os), tx);
1698 
1699 	os->os_phys->os_flags = os->os_flags;
1700 
1701 	if (DMU_USERUSED_DNODE(os) &&
1702 	    DMU_USERUSED_DNODE(os)->dn_type != DMU_OT_NONE) {
1703 		DMU_USERUSED_DNODE(os)->dn_zio = zio;
1704 		dnode_sync(DMU_USERUSED_DNODE(os), tx);
1705 		DMU_GROUPUSED_DNODE(os)->dn_zio = zio;
1706 		dnode_sync(DMU_GROUPUSED_DNODE(os), tx);
1707 	}
1708 
1709 	if (DMU_PROJECTUSED_DNODE(os) &&
1710 	    DMU_PROJECTUSED_DNODE(os)->dn_type != DMU_OT_NONE) {
1711 		DMU_PROJECTUSED_DNODE(os)->dn_zio = zio;
1712 		dnode_sync(DMU_PROJECTUSED_DNODE(os), tx);
1713 	}
1714 
1715 	txgoff = tx->tx_txg & TXG_MASK;
1716 
1717 	if (dmu_objset_userused_enabled(os) &&
1718 	    (!os->os_encrypted || !dmu_objset_is_receiving(os))) {
1719 		/*
1720 		 * We must create the list here because it uses the
1721 		 * dn_dirty_link[] of this txg.  But it may already
1722 		 * exist because we call dsl_dataset_sync() twice per txg.
1723 		 */
1724 		if (os->os_synced_dnodes == NULL) {
1725 			os->os_synced_dnodes =
1726 			    multilist_create(sizeof (dnode_t),
1727 			    offsetof(dnode_t, dn_dirty_link[txgoff]),
1728 			    dnode_multilist_index_func);
1729 		} else {
1730 			ASSERT3U(os->os_synced_dnodes->ml_offset, ==,
1731 			    offsetof(dnode_t, dn_dirty_link[txgoff]));
1732 		}
1733 	}
1734 
1735 	for (int i = 0;
1736 	    i < multilist_get_num_sublists(os->os_dirty_dnodes[txgoff]); i++) {
1737 		sync_dnodes_arg_t *sda = kmem_alloc(sizeof (*sda), KM_SLEEP);
1738 		sda->sda_list = os->os_dirty_dnodes[txgoff];
1739 		sda->sda_sublist_idx = i;
1740 		sda->sda_tx = tx;
1741 		(void) taskq_dispatch(dmu_objset_pool(os)->dp_sync_taskq,
1742 		    sync_dnodes_task, sda, 0);
1743 		/* callback frees sda */
1744 	}
1745 	taskq_wait(dmu_objset_pool(os)->dp_sync_taskq);
1746 
1747 	list = &DMU_META_DNODE(os)->dn_dirty_records[txgoff];
1748 	while ((dr = list_head(list)) != NULL) {
1749 		ASSERT0(dr->dr_dbuf->db_level);
1750 		list_remove(list, dr);
1751 		if (dr->dr_zio)
1752 			zio_nowait(dr->dr_zio);
1753 	}
1754 
1755 	/* Enable dnode backfill if enough objects have been freed. */
1756 	if (os->os_freed_dnodes >= dmu_rescan_dnode_threshold) {
1757 		os->os_rescan_dnodes = B_TRUE;
1758 		os->os_freed_dnodes = 0;
1759 	}
1760 
1761 	/*
1762 	 * Free intent log blocks up to this tx.
1763 	 */
1764 	zil_sync(os->os_zil, tx);
1765 	os->os_phys->os_zil_header = os->os_zil_header;
1766 	zio_nowait(zio);
1767 }
1768 
1769 boolean_t
1770 dmu_objset_is_dirty(objset_t *os, uint64_t txg)
1771 {
1772 	return (!multilist_is_empty(os->os_dirty_dnodes[txg & TXG_MASK]));
1773 }
1774 
1775 static objset_used_cb_t *used_cbs[DMU_OST_NUMTYPES];
1776 
1777 void
1778 dmu_objset_register_type(dmu_objset_type_t ost, objset_used_cb_t *cb)
1779 {
1780 	used_cbs[ost] = cb;
1781 }
1782 
1783 boolean_t
1784 dmu_objset_userused_enabled(objset_t *os)
1785 {
1786 	return (spa_version(os->os_spa) >= SPA_VERSION_USERSPACE &&
1787 	    used_cbs[os->os_phys->os_type] != NULL &&
1788 	    DMU_USERUSED_DNODE(os) != NULL);
1789 }
1790 
1791 boolean_t
1792 dmu_objset_userobjused_enabled(objset_t *os)
1793 {
1794 	return (dmu_objset_userused_enabled(os) &&
1795 	    spa_feature_is_enabled(os->os_spa, SPA_FEATURE_USEROBJ_ACCOUNTING));
1796 }
1797 
1798 boolean_t
1799 dmu_objset_projectquota_enabled(objset_t *os)
1800 {
1801 	return (used_cbs[os->os_phys->os_type] != NULL &&
1802 	    DMU_PROJECTUSED_DNODE(os) != NULL &&
1803 	    spa_feature_is_enabled(os->os_spa, SPA_FEATURE_PROJECT_QUOTA));
1804 }
1805 
1806 typedef struct userquota_node {
1807 	/* must be in the first field, see userquota_update_cache() */
1808 	char		uqn_id[20 + DMU_OBJACCT_PREFIX_LEN];
1809 	int64_t		uqn_delta;
1810 	avl_node_t	uqn_node;
1811 } userquota_node_t;
1812 
1813 typedef struct userquota_cache {
1814 	avl_tree_t uqc_user_deltas;
1815 	avl_tree_t uqc_group_deltas;
1816 	avl_tree_t uqc_project_deltas;
1817 } userquota_cache_t;
1818 
1819 static int
1820 userquota_compare(const void *l, const void *r)
1821 {
1822 	const userquota_node_t *luqn = l;
1823 	const userquota_node_t *ruqn = r;
1824 	int rv;
1825 
1826 	/*
1827 	 * NB: can only access uqn_id because userquota_update_cache() doesn't
1828 	 * pass in an entire userquota_node_t.
1829 	 */
1830 	rv = strcmp(luqn->uqn_id, ruqn->uqn_id);
1831 
1832 	return (TREE_ISIGN(rv));
1833 }
1834 
1835 static void
1836 do_userquota_cacheflush(objset_t *os, userquota_cache_t *cache, dmu_tx_t *tx)
1837 {
1838 	void *cookie;
1839 	userquota_node_t *uqn;
1840 
1841 	ASSERT(dmu_tx_is_syncing(tx));
1842 
1843 	cookie = NULL;
1844 	while ((uqn = avl_destroy_nodes(&cache->uqc_user_deltas,
1845 	    &cookie)) != NULL) {
1846 		/*
1847 		 * os_userused_lock protects against concurrent calls to
1848 		 * zap_increment_int().  It's needed because zap_increment_int()
1849 		 * is not thread-safe (i.e. not atomic).
1850 		 */
1851 		mutex_enter(&os->os_userused_lock);
1852 		VERIFY0(zap_increment(os, DMU_USERUSED_OBJECT,
1853 		    uqn->uqn_id, uqn->uqn_delta, tx));
1854 		mutex_exit(&os->os_userused_lock);
1855 		kmem_free(uqn, sizeof (*uqn));
1856 	}
1857 	avl_destroy(&cache->uqc_user_deltas);
1858 
1859 	cookie = NULL;
1860 	while ((uqn = avl_destroy_nodes(&cache->uqc_group_deltas,
1861 	    &cookie)) != NULL) {
1862 		mutex_enter(&os->os_userused_lock);
1863 		VERIFY0(zap_increment(os, DMU_GROUPUSED_OBJECT,
1864 		    uqn->uqn_id, uqn->uqn_delta, tx));
1865 		mutex_exit(&os->os_userused_lock);
1866 		kmem_free(uqn, sizeof (*uqn));
1867 	}
1868 	avl_destroy(&cache->uqc_group_deltas);
1869 
1870 	if (dmu_objset_projectquota_enabled(os)) {
1871 		cookie = NULL;
1872 		while ((uqn = avl_destroy_nodes(&cache->uqc_project_deltas,
1873 		    &cookie)) != NULL) {
1874 			mutex_enter(&os->os_userused_lock);
1875 			VERIFY0(zap_increment(os, DMU_PROJECTUSED_OBJECT,
1876 			    uqn->uqn_id, uqn->uqn_delta, tx));
1877 			mutex_exit(&os->os_userused_lock);
1878 			kmem_free(uqn, sizeof (*uqn));
1879 		}
1880 		avl_destroy(&cache->uqc_project_deltas);
1881 	}
1882 }
1883 
1884 static void
1885 userquota_update_cache(avl_tree_t *avl, const char *id, int64_t delta)
1886 {
1887 	userquota_node_t *uqn;
1888 	avl_index_t idx;
1889 
1890 	ASSERT(strlen(id) < sizeof (uqn->uqn_id));
1891 	/*
1892 	 * Use id directly for searching because uqn_id is the first field of
1893 	 * userquota_node_t and fields after uqn_id won't be accessed in
1894 	 * avl_find().
1895 	 */
1896 	uqn = avl_find(avl, (const void *)id, &idx);
1897 	if (uqn == NULL) {
1898 		uqn = kmem_zalloc(sizeof (*uqn), KM_SLEEP);
1899 		(void) strlcpy(uqn->uqn_id, id, sizeof (uqn->uqn_id));
1900 		avl_insert(avl, uqn, idx);
1901 	}
1902 	uqn->uqn_delta += delta;
1903 }
1904 
1905 static void
1906 do_userquota_update(objset_t *os, userquota_cache_t *cache, uint64_t used,
1907     uint64_t flags, uint64_t user, uint64_t group, uint64_t project,
1908     boolean_t subtract)
1909 {
1910 	if ((flags & DNODE_FLAG_USERUSED_ACCOUNTED)) {
1911 		int64_t delta = DNODE_MIN_SIZE + used;
1912 		char name[20];
1913 
1914 		if (subtract)
1915 			delta = -delta;
1916 
1917 		(void) sprintf(name, "%llx", (longlong_t)user);
1918 		userquota_update_cache(&cache->uqc_user_deltas, name, delta);
1919 
1920 		(void) sprintf(name, "%llx", (longlong_t)group);
1921 		userquota_update_cache(&cache->uqc_group_deltas, name, delta);
1922 
1923 		if (dmu_objset_projectquota_enabled(os)) {
1924 			(void) sprintf(name, "%llx", (longlong_t)project);
1925 			userquota_update_cache(&cache->uqc_project_deltas,
1926 			    name, delta);
1927 		}
1928 	}
1929 }
1930 
1931 static void
1932 do_userobjquota_update(objset_t *os, userquota_cache_t *cache, uint64_t flags,
1933     uint64_t user, uint64_t group, uint64_t project, boolean_t subtract)
1934 {
1935 	if (flags & DNODE_FLAG_USEROBJUSED_ACCOUNTED) {
1936 		char name[20 + DMU_OBJACCT_PREFIX_LEN];
1937 		int delta = subtract ? -1 : 1;
1938 
1939 		(void) snprintf(name, sizeof (name), DMU_OBJACCT_PREFIX "%llx",
1940 		    (longlong_t)user);
1941 		userquota_update_cache(&cache->uqc_user_deltas, name, delta);
1942 
1943 		(void) snprintf(name, sizeof (name), DMU_OBJACCT_PREFIX "%llx",
1944 		    (longlong_t)group);
1945 		userquota_update_cache(&cache->uqc_group_deltas, name, delta);
1946 
1947 		if (dmu_objset_projectquota_enabled(os)) {
1948 			(void) snprintf(name, sizeof (name),
1949 			    DMU_OBJACCT_PREFIX "%llx", (longlong_t)project);
1950 			userquota_update_cache(&cache->uqc_project_deltas,
1951 			    name, delta);
1952 		}
1953 	}
1954 }
1955 
1956 typedef struct userquota_updates_arg {
1957 	objset_t *uua_os;
1958 	int uua_sublist_idx;
1959 	dmu_tx_t *uua_tx;
1960 } userquota_updates_arg_t;
1961 
1962 static void
1963 userquota_updates_task(void *arg)
1964 {
1965 	userquota_updates_arg_t *uua = arg;
1966 	objset_t *os = uua->uua_os;
1967 	dmu_tx_t *tx = uua->uua_tx;
1968 	dnode_t *dn;
1969 	userquota_cache_t cache = { 0 };
1970 
1971 	multilist_sublist_t *list =
1972 	    multilist_sublist_lock(os->os_synced_dnodes, uua->uua_sublist_idx);
1973 
1974 	ASSERT(multilist_sublist_head(list) == NULL ||
1975 	    dmu_objset_userused_enabled(os));
1976 	avl_create(&cache.uqc_user_deltas, userquota_compare,
1977 	    sizeof (userquota_node_t), offsetof(userquota_node_t, uqn_node));
1978 	avl_create(&cache.uqc_group_deltas, userquota_compare,
1979 	    sizeof (userquota_node_t), offsetof(userquota_node_t, uqn_node));
1980 	if (dmu_objset_projectquota_enabled(os))
1981 		avl_create(&cache.uqc_project_deltas, userquota_compare,
1982 		    sizeof (userquota_node_t), offsetof(userquota_node_t,
1983 		    uqn_node));
1984 
1985 	while ((dn = multilist_sublist_head(list)) != NULL) {
1986 		int flags;
1987 		ASSERT(!DMU_OBJECT_IS_SPECIAL(dn->dn_object));
1988 		ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE ||
1989 		    dn->dn_phys->dn_flags &
1990 		    DNODE_FLAG_USERUSED_ACCOUNTED);
1991 
1992 		flags = dn->dn_id_flags;
1993 		ASSERT(flags);
1994 		if (flags & DN_ID_OLD_EXIST)  {
1995 			do_userquota_update(os, &cache, dn->dn_oldused,
1996 			    dn->dn_oldflags, dn->dn_olduid, dn->dn_oldgid,
1997 			    dn->dn_oldprojid, B_TRUE);
1998 			do_userobjquota_update(os, &cache, dn->dn_oldflags,
1999 			    dn->dn_olduid, dn->dn_oldgid,
2000 			    dn->dn_oldprojid, B_TRUE);
2001 		}
2002 		if (flags & DN_ID_NEW_EXIST) {
2003 			do_userquota_update(os, &cache,
2004 			    DN_USED_BYTES(dn->dn_phys), dn->dn_phys->dn_flags,
2005 			    dn->dn_newuid, dn->dn_newgid,
2006 			    dn->dn_newprojid, B_FALSE);
2007 			do_userobjquota_update(os, &cache,
2008 			    dn->dn_phys->dn_flags, dn->dn_newuid, dn->dn_newgid,
2009 			    dn->dn_newprojid, B_FALSE);
2010 		}
2011 
2012 		mutex_enter(&dn->dn_mtx);
2013 		dn->dn_oldused = 0;
2014 		dn->dn_oldflags = 0;
2015 		if (dn->dn_id_flags & DN_ID_NEW_EXIST) {
2016 			dn->dn_olduid = dn->dn_newuid;
2017 			dn->dn_oldgid = dn->dn_newgid;
2018 			dn->dn_oldprojid = dn->dn_newprojid;
2019 			dn->dn_id_flags |= DN_ID_OLD_EXIST;
2020 			if (dn->dn_bonuslen == 0)
2021 				dn->dn_id_flags |= DN_ID_CHKED_SPILL;
2022 			else
2023 				dn->dn_id_flags |= DN_ID_CHKED_BONUS;
2024 		}
2025 		dn->dn_id_flags &= ~(DN_ID_NEW_EXIST);
2026 		if (dn->dn_dirty_txg == spa_syncing_txg(os->os_spa))
2027 			dn->dn_dirty_txg = 0;
2028 		mutex_exit(&dn->dn_mtx);
2029 
2030 		multilist_sublist_remove(list, dn);
2031 		dnode_rele(dn, os->os_synced_dnodes);
2032 	}
2033 	do_userquota_cacheflush(os, &cache, tx);
2034 	multilist_sublist_unlock(list);
2035 	kmem_free(uua, sizeof (*uua));
2036 }
2037 
2038 void
2039 dmu_objset_do_userquota_updates(objset_t *os, dmu_tx_t *tx)
2040 {
2041 	if (!dmu_objset_userused_enabled(os))
2042 		return;
2043 
2044 	/*
2045 	 * If this is a raw receive just return and handle accounting
2046 	 * later when we have the keys loaded. We also don't do user
2047 	 * accounting during claiming since the datasets are not owned
2048 	 * for the duration of claiming and this txg should only be
2049 	 * used for recovery.
2050 	 */
2051 	if (os->os_encrypted && dmu_objset_is_receiving(os))
2052 		return;
2053 
2054 	if (tx->tx_txg <= os->os_spa->spa_claim_max_txg)
2055 		return;
2056 
2057 	/* Allocate the user/group/project used objects if necessary. */
2058 	if (DMU_USERUSED_DNODE(os)->dn_type == DMU_OT_NONE) {
2059 		VERIFY0(zap_create_claim(os,
2060 		    DMU_USERUSED_OBJECT,
2061 		    DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
2062 		VERIFY0(zap_create_claim(os,
2063 		    DMU_GROUPUSED_OBJECT,
2064 		    DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
2065 	}
2066 
2067 	if (dmu_objset_projectquota_enabled(os) &&
2068 	    DMU_PROJECTUSED_DNODE(os)->dn_type == DMU_OT_NONE) {
2069 		VERIFY0(zap_create_claim(os, DMU_PROJECTUSED_OBJECT,
2070 		    DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
2071 	}
2072 
2073 	for (int i = 0;
2074 	    i < multilist_get_num_sublists(os->os_synced_dnodes); i++) {
2075 		userquota_updates_arg_t *uua =
2076 		    kmem_alloc(sizeof (*uua), KM_SLEEP);
2077 		uua->uua_os = os;
2078 		uua->uua_sublist_idx = i;
2079 		uua->uua_tx = tx;
2080 		/* note: caller does taskq_wait() */
2081 		(void) taskq_dispatch(dmu_objset_pool(os)->dp_sync_taskq,
2082 		    userquota_updates_task, uua, 0);
2083 		/* callback frees uua */
2084 	}
2085 }
2086 
2087 /*
2088  * Returns a pointer to data to find uid/gid from
2089  *
2090  * If a dirty record for transaction group that is syncing can't
2091  * be found then NULL is returned.  In the NULL case it is assumed
2092  * the uid/gid aren't changing.
2093  */
2094 static void *
2095 dmu_objset_userquota_find_data(dmu_buf_impl_t *db, dmu_tx_t *tx)
2096 {
2097 	dbuf_dirty_record_t *dr, **drp;
2098 	void *data;
2099 
2100 	if (db->db_dirtycnt == 0)
2101 		return (db->db.db_data);  /* Nothing is changing */
2102 
2103 	for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
2104 		if (dr->dr_txg == tx->tx_txg)
2105 			break;
2106 
2107 	if (dr == NULL) {
2108 		data = NULL;
2109 	} else {
2110 		dnode_t *dn;
2111 
2112 		DB_DNODE_ENTER(dr->dr_dbuf);
2113 		dn = DB_DNODE(dr->dr_dbuf);
2114 
2115 		if (dn->dn_bonuslen == 0 &&
2116 		    dr->dr_dbuf->db_blkid == DMU_SPILL_BLKID)
2117 			data = dr->dt.dl.dr_data->b_data;
2118 		else
2119 			data = dr->dt.dl.dr_data;
2120 
2121 		DB_DNODE_EXIT(dr->dr_dbuf);
2122 	}
2123 
2124 	return (data);
2125 }
2126 
2127 void
2128 dmu_objset_userquota_get_ids(dnode_t *dn, boolean_t before, dmu_tx_t *tx)
2129 {
2130 	objset_t *os = dn->dn_objset;
2131 	void *data = NULL;
2132 	dmu_buf_impl_t *db = NULL;
2133 	uint64_t *user = NULL;
2134 	uint64_t *group = NULL;
2135 	uint64_t *project = NULL;
2136 	int flags = dn->dn_id_flags;
2137 	int error;
2138 	boolean_t have_spill = B_FALSE;
2139 
2140 	if (!dmu_objset_userused_enabled(dn->dn_objset))
2141 		return;
2142 
2143 	/*
2144 	 * Raw receives introduce a problem with user accounting. Raw
2145 	 * receives cannot update the user accounting info because the
2146 	 * user ids and the sizes are encrypted. To guarantee that we
2147 	 * never end up with bad user accounting, we simply disable it
2148 	 * during raw receives. We also disable this for normal receives
2149 	 * so that an incremental raw receive may be done on top of an
2150 	 * existing non-raw receive.
2151 	 */
2152 	if (os->os_encrypted && dmu_objset_is_receiving(os))
2153 		return;
2154 
2155 	if (before && (flags & (DN_ID_CHKED_BONUS|DN_ID_OLD_EXIST|
2156 	    DN_ID_CHKED_SPILL)))
2157 		return;
2158 
2159 	if (before && dn->dn_bonuslen != 0)
2160 		data = DN_BONUS(dn->dn_phys);
2161 	else if (!before && dn->dn_bonuslen != 0) {
2162 		if (dn->dn_bonus) {
2163 			db = dn->dn_bonus;
2164 			mutex_enter(&db->db_mtx);
2165 			data = dmu_objset_userquota_find_data(db, tx);
2166 		} else {
2167 			data = DN_BONUS(dn->dn_phys);
2168 		}
2169 	} else if (dn->dn_bonuslen == 0 && dn->dn_bonustype == DMU_OT_SA) {
2170 			int rf = 0;
2171 
2172 			if (RW_WRITE_HELD(&dn->dn_struct_rwlock))
2173 				rf |= DB_RF_HAVESTRUCT;
2174 			error = dmu_spill_hold_by_dnode(dn,
2175 			    rf | DB_RF_MUST_SUCCEED,
2176 			    FTAG, (dmu_buf_t **)&db);
2177 			ASSERT(error == 0);
2178 			mutex_enter(&db->db_mtx);
2179 			data = (before) ? db->db.db_data :
2180 			    dmu_objset_userquota_find_data(db, tx);
2181 			have_spill = B_TRUE;
2182 	} else {
2183 		mutex_enter(&dn->dn_mtx);
2184 		dn->dn_id_flags |= DN_ID_CHKED_BONUS;
2185 		mutex_exit(&dn->dn_mtx);
2186 		return;
2187 	}
2188 
2189 	if (before) {
2190 		ASSERT(data);
2191 		user = &dn->dn_olduid;
2192 		group = &dn->dn_oldgid;
2193 		project = &dn->dn_oldprojid;
2194 	} else if (data) {
2195 		user = &dn->dn_newuid;
2196 		group = &dn->dn_newgid;
2197 		project = &dn->dn_newprojid;
2198 	}
2199 
2200 	/*
2201 	 * Must always call the callback in case the object
2202 	 * type has changed and that type isn't an object type to track
2203 	 */
2204 	error = used_cbs[os->os_phys->os_type](dn->dn_bonustype, data,
2205 	    user, group, project);
2206 
2207 	/*
2208 	 * Preserve existing uid/gid when the callback can't determine
2209 	 * what the new uid/gid are and the callback returned EEXIST.
2210 	 * The EEXIST error tells us to just use the existing uid/gid.
2211 	 * If we don't know what the old values are then just assign
2212 	 * them to 0, since that is a new file  being created.
2213 	 */
2214 	if (!before && data == NULL && error == EEXIST) {
2215 		if (flags & DN_ID_OLD_EXIST) {
2216 			dn->dn_newuid = dn->dn_olduid;
2217 			dn->dn_newgid = dn->dn_oldgid;
2218 			dn->dn_newgid = dn->dn_oldprojid;
2219 		} else {
2220 			dn->dn_newuid = 0;
2221 			dn->dn_newgid = 0;
2222 			dn->dn_newprojid = ZFS_DEFAULT_PROJID;
2223 		}
2224 		error = 0;
2225 	}
2226 
2227 	if (db)
2228 		mutex_exit(&db->db_mtx);
2229 
2230 	mutex_enter(&dn->dn_mtx);
2231 	if (error == 0 && before)
2232 		dn->dn_id_flags |= DN_ID_OLD_EXIST;
2233 	if (error == 0 && !before)
2234 		dn->dn_id_flags |= DN_ID_NEW_EXIST;
2235 
2236 	if (have_spill) {
2237 		dn->dn_id_flags |= DN_ID_CHKED_SPILL;
2238 	} else {
2239 		dn->dn_id_flags |= DN_ID_CHKED_BONUS;
2240 	}
2241 	mutex_exit(&dn->dn_mtx);
2242 	if (have_spill)
2243 		dmu_buf_rele((dmu_buf_t *)db, FTAG);
2244 }
2245 
2246 boolean_t
2247 dmu_objset_userspace_present(objset_t *os)
2248 {
2249 	return (os->os_phys->os_flags &
2250 	    OBJSET_FLAG_USERACCOUNTING_COMPLETE);
2251 }
2252 
2253 boolean_t
2254 dmu_objset_userobjspace_present(objset_t *os)
2255 {
2256 	return (os->os_phys->os_flags &
2257 	    OBJSET_FLAG_USEROBJACCOUNTING_COMPLETE);
2258 }
2259 
2260 boolean_t
2261 dmu_objset_projectquota_present(objset_t *os)
2262 {
2263 	return (os->os_phys->os_flags &
2264 	    OBJSET_FLAG_PROJECTQUOTA_COMPLETE);
2265 }
2266 
2267 static int
2268 dmu_objset_space_upgrade(objset_t *os)
2269 {
2270 	uint64_t obj;
2271 	int err = 0;
2272 
2273 	/*
2274 	 * We simply need to mark every object dirty, so that it will be
2275 	 * synced out and now accounted.  If this is called
2276 	 * concurrently, or if we already did some work before crashing,
2277 	 * that's fine, since we track each object's accounted state
2278 	 * independently.
2279 	 */
2280 
2281 	for (obj = 0; err == 0; err = dmu_object_next(os, &obj, FALSE, 0)) {
2282 		dmu_tx_t *tx;
2283 		dmu_buf_t *db;
2284 		int objerr;
2285 
2286 		mutex_enter(&os->os_upgrade_lock);
2287 		if (os->os_upgrade_exit)
2288 			err = SET_ERROR(EINTR);
2289 		mutex_exit(&os->os_upgrade_lock);
2290 		if (err != 0)
2291 			return (err);
2292 
2293 		/*
2294 		 * The following is only valid on Linux since we cannot send
2295 		 * a signal to a kernel thread on illumos (because we have no
2296 		 * lwp and never return to user-land).
2297 		 *
2298 		 * if (issig(JUSTLOOKING) && issig(FORREAL))
2299 		 *    return (SET_ERROR(EINTR));
2300 		 */
2301 
2302 		objerr = dmu_bonus_hold(os, obj, FTAG, &db);
2303 		if (objerr != 0)
2304 			continue;
2305 		tx = dmu_tx_create(os);
2306 		dmu_tx_hold_bonus(tx, obj);
2307 		objerr = dmu_tx_assign(tx, TXG_WAIT);
2308 		if (objerr != 0) {
2309 			dmu_tx_abort(tx);
2310 			continue;
2311 		}
2312 		dmu_buf_will_dirty(db, tx);
2313 		dmu_buf_rele(db, FTAG);
2314 		dmu_tx_commit(tx);
2315 	}
2316 	return (0);
2317 }
2318 
2319 int
2320 dmu_objset_userspace_upgrade(objset_t *os)
2321 {
2322 	int err = 0;
2323 
2324 	if (dmu_objset_userspace_present(os))
2325 		return (0);
2326 	if (dmu_objset_is_snapshot(os))
2327 		return (SET_ERROR(EINVAL));
2328 	if (!dmu_objset_userused_enabled(os))
2329 		return (SET_ERROR(ENOTSUP));
2330 
2331 	err = dmu_objset_space_upgrade(os);
2332 	if (err)
2333 		return (err);
2334 
2335 	os->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
2336 	txg_wait_synced(dmu_objset_pool(os), 0);
2337 	return (0);
2338 }
2339 
2340 static int
2341 dmu_objset_id_quota_upgrade_cb(objset_t *os)
2342 {
2343 	int err = 0;
2344 
2345 	if (dmu_objset_userobjspace_present(os) &&
2346 	    dmu_objset_projectquota_present(os))
2347 		return (0);
2348 	if (dmu_objset_is_snapshot(os))
2349 		return (SET_ERROR(EINVAL));
2350 	if (!dmu_objset_userobjused_enabled(os))
2351 		return (SET_ERROR(ENOTSUP));
2352 	if (!dmu_objset_projectquota_enabled(os) &&
2353 	    dmu_objset_userobjspace_present(os))
2354 		return (SET_ERROR(ENOTSUP));
2355 
2356 	dmu_objset_ds(os)->ds_feature_activation_needed[
2357 	    SPA_FEATURE_USEROBJ_ACCOUNTING] = B_TRUE;
2358 	if (dmu_objset_projectquota_enabled(os))
2359 		dmu_objset_ds(os)->ds_feature_activation_needed[
2360 		    SPA_FEATURE_PROJECT_QUOTA] = B_TRUE;
2361 
2362 	err = dmu_objset_space_upgrade(os);
2363 	if (err)
2364 		return (err);
2365 
2366 	os->os_flags |= OBJSET_FLAG_USEROBJACCOUNTING_COMPLETE;
2367 	if (dmu_objset_projectquota_enabled(os))
2368 		os->os_flags |= OBJSET_FLAG_PROJECTQUOTA_COMPLETE;
2369 
2370 	txg_wait_synced(dmu_objset_pool(os), 0);
2371 	return (0);
2372 }
2373 
2374 void
2375 dmu_objset_id_quota_upgrade(objset_t *os)
2376 {
2377 	dmu_objset_upgrade(os, dmu_objset_id_quota_upgrade_cb);
2378 }
2379 
2380 boolean_t
2381 dmu_objset_userobjspace_upgradable(objset_t *os)
2382 {
2383 	return (dmu_objset_type(os) == DMU_OST_ZFS &&
2384 	    !dmu_objset_is_snapshot(os) &&
2385 	    dmu_objset_userobjused_enabled(os) &&
2386 	    !dmu_objset_userobjspace_present(os) &&
2387 	    spa_writeable(dmu_objset_spa(os)));
2388 }
2389 
2390 boolean_t
2391 dmu_objset_projectquota_upgradable(objset_t *os)
2392 {
2393 	return (dmu_objset_type(os) == DMU_OST_ZFS &&
2394 	    !dmu_objset_is_snapshot(os) &&
2395 	    dmu_objset_projectquota_enabled(os) &&
2396 	    !dmu_objset_projectquota_present(os) &&
2397 	    spa_writeable(dmu_objset_spa(os)));
2398 }
2399 
2400 void
2401 dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
2402     uint64_t *usedobjsp, uint64_t *availobjsp)
2403 {
2404 	dsl_dataset_space(os->os_dsl_dataset, refdbytesp, availbytesp,
2405 	    usedobjsp, availobjsp);
2406 }
2407 
2408 uint64_t
2409 dmu_objset_fsid_guid(objset_t *os)
2410 {
2411 	return (dsl_dataset_fsid_guid(os->os_dsl_dataset));
2412 }
2413 
2414 void
2415 dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat)
2416 {
2417 	stat->dds_type = os->os_phys->os_type;
2418 	if (os->os_dsl_dataset)
2419 		dsl_dataset_fast_stat(os->os_dsl_dataset, stat);
2420 }
2421 
2422 void
2423 dmu_objset_stats(objset_t *os, nvlist_t *nv)
2424 {
2425 	ASSERT(os->os_dsl_dataset ||
2426 	    os->os_phys->os_type == DMU_OST_META);
2427 
2428 	if (os->os_dsl_dataset != NULL)
2429 		dsl_dataset_stats(os->os_dsl_dataset, nv);
2430 
2431 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_TYPE,
2432 	    os->os_phys->os_type);
2433 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERACCOUNTING,
2434 	    dmu_objset_userspace_present(os));
2435 }
2436 
2437 int
2438 dmu_objset_is_snapshot(objset_t *os)
2439 {
2440 	if (os->os_dsl_dataset != NULL)
2441 		return (os->os_dsl_dataset->ds_is_snapshot);
2442 	else
2443 		return (B_FALSE);
2444 }
2445 
2446 int
2447 dmu_snapshot_realname(objset_t *os, char *name, char *real, int maxlen,
2448     boolean_t *conflict)
2449 {
2450 	dsl_dataset_t *ds = os->os_dsl_dataset;
2451 	uint64_t ignored;
2452 
2453 	if (dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0)
2454 		return (SET_ERROR(ENOENT));
2455 
2456 	return (zap_lookup_norm(ds->ds_dir->dd_pool->dp_meta_objset,
2457 	    dsl_dataset_phys(ds)->ds_snapnames_zapobj, name, 8, 1, &ignored,
2458 	    MT_NORMALIZE, real, maxlen, conflict));
2459 }
2460 
2461 int
2462 dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
2463     uint64_t *idp, uint64_t *offp, boolean_t *case_conflict)
2464 {
2465 	dsl_dataset_t *ds = os->os_dsl_dataset;
2466 	zap_cursor_t cursor;
2467 	zap_attribute_t attr;
2468 
2469 	ASSERT(dsl_pool_config_held(dmu_objset_pool(os)));
2470 
2471 	if (dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0)
2472 		return (SET_ERROR(ENOENT));
2473 
2474 	zap_cursor_init_serialized(&cursor,
2475 	    ds->ds_dir->dd_pool->dp_meta_objset,
2476 	    dsl_dataset_phys(ds)->ds_snapnames_zapobj, *offp);
2477 
2478 	if (zap_cursor_retrieve(&cursor, &attr) != 0) {
2479 		zap_cursor_fini(&cursor);
2480 		return (SET_ERROR(ENOENT));
2481 	}
2482 
2483 	if (strlen(attr.za_name) + 1 > namelen) {
2484 		zap_cursor_fini(&cursor);
2485 		return (SET_ERROR(ENAMETOOLONG));
2486 	}
2487 
2488 	(void) strcpy(name, attr.za_name);
2489 	if (idp)
2490 		*idp = attr.za_first_integer;
2491 	if (case_conflict)
2492 		*case_conflict = attr.za_normalization_conflict;
2493 	zap_cursor_advance(&cursor);
2494 	*offp = zap_cursor_serialize(&cursor);
2495 	zap_cursor_fini(&cursor);
2496 
2497 	return (0);
2498 }
2499 
2500 int
2501 dmu_dir_list_next(objset_t *os, int namelen, char *name,
2502     uint64_t *idp, uint64_t *offp)
2503 {
2504 	dsl_dir_t *dd = os->os_dsl_dataset->ds_dir;
2505 	zap_cursor_t cursor;
2506 	zap_attribute_t attr;
2507 
2508 	/* there is no next dir on a snapshot! */
2509 	if (os->os_dsl_dataset->ds_object !=
2510 	    dsl_dir_phys(dd)->dd_head_dataset_obj)
2511 		return (SET_ERROR(ENOENT));
2512 
2513 	zap_cursor_init_serialized(&cursor,
2514 	    dd->dd_pool->dp_meta_objset,
2515 	    dsl_dir_phys(dd)->dd_child_dir_zapobj, *offp);
2516 
2517 	if (zap_cursor_retrieve(&cursor, &attr) != 0) {
2518 		zap_cursor_fini(&cursor);
2519 		return (SET_ERROR(ENOENT));
2520 	}
2521 
2522 	if (strlen(attr.za_name) + 1 > namelen) {
2523 		zap_cursor_fini(&cursor);
2524 		return (SET_ERROR(ENAMETOOLONG));
2525 	}
2526 
2527 	(void) strcpy(name, attr.za_name);
2528 	if (idp)
2529 		*idp = attr.za_first_integer;
2530 	zap_cursor_advance(&cursor);
2531 	*offp = zap_cursor_serialize(&cursor);
2532 	zap_cursor_fini(&cursor);
2533 
2534 	return (0);
2535 }
2536 
2537 typedef struct dmu_objset_find_ctx {
2538 	taskq_t		*dc_tq;
2539 	dsl_pool_t	*dc_dp;
2540 	uint64_t	dc_ddobj;
2541 	char		*dc_ddname; /* last component of ddobj's name */
2542 	int		(*dc_func)(dsl_pool_t *, dsl_dataset_t *, void *);
2543 	void		*dc_arg;
2544 	int		dc_flags;
2545 	kmutex_t	*dc_error_lock;
2546 	int		*dc_error;
2547 } dmu_objset_find_ctx_t;
2548 
2549 static void
2550 dmu_objset_find_dp_impl(dmu_objset_find_ctx_t *dcp)
2551 {
2552 	dsl_pool_t *dp = dcp->dc_dp;
2553 	dsl_dir_t *dd;
2554 	dsl_dataset_t *ds;
2555 	zap_cursor_t zc;
2556 	zap_attribute_t *attr;
2557 	uint64_t thisobj;
2558 	int err = 0;
2559 
2560 	/* don't process if there already was an error */
2561 	if (*dcp->dc_error != 0)
2562 		goto out;
2563 
2564 	/*
2565 	 * Note: passing the name (dc_ddname) here is optional, but it
2566 	 * improves performance because we don't need to call
2567 	 * zap_value_search() to determine the name.
2568 	 */
2569 	err = dsl_dir_hold_obj(dp, dcp->dc_ddobj, dcp->dc_ddname, FTAG, &dd);
2570 	if (err != 0)
2571 		goto out;
2572 
2573 	/* Don't visit hidden ($MOS & $ORIGIN) objsets. */
2574 	if (dd->dd_myname[0] == '$') {
2575 		dsl_dir_rele(dd, FTAG);
2576 		goto out;
2577 	}
2578 
2579 	thisobj = dsl_dir_phys(dd)->dd_head_dataset_obj;
2580 	attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
2581 
2582 	/*
2583 	 * Iterate over all children.
2584 	 */
2585 	if (dcp->dc_flags & DS_FIND_CHILDREN) {
2586 		for (zap_cursor_init(&zc, dp->dp_meta_objset,
2587 		    dsl_dir_phys(dd)->dd_child_dir_zapobj);
2588 		    zap_cursor_retrieve(&zc, attr) == 0;
2589 		    (void) zap_cursor_advance(&zc)) {
2590 			ASSERT3U(attr->za_integer_length, ==,
2591 			    sizeof (uint64_t));
2592 			ASSERT3U(attr->za_num_integers, ==, 1);
2593 
2594 			dmu_objset_find_ctx_t *child_dcp =
2595 			    kmem_alloc(sizeof (*child_dcp), KM_SLEEP);
2596 			*child_dcp = *dcp;
2597 			child_dcp->dc_ddobj = attr->za_first_integer;
2598 			child_dcp->dc_ddname = spa_strdup(attr->za_name);
2599 			if (dcp->dc_tq != NULL)
2600 				(void) taskq_dispatch(dcp->dc_tq,
2601 				    dmu_objset_find_dp_cb, child_dcp, TQ_SLEEP);
2602 			else
2603 				dmu_objset_find_dp_impl(child_dcp);
2604 		}
2605 		zap_cursor_fini(&zc);
2606 	}
2607 
2608 	/*
2609 	 * Iterate over all snapshots.
2610 	 */
2611 	if (dcp->dc_flags & DS_FIND_SNAPSHOTS) {
2612 		dsl_dataset_t *ds;
2613 		err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
2614 
2615 		if (err == 0) {
2616 			uint64_t snapobj;
2617 
2618 			snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
2619 			dsl_dataset_rele(ds, FTAG);
2620 
2621 			for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
2622 			    zap_cursor_retrieve(&zc, attr) == 0;
2623 			    (void) zap_cursor_advance(&zc)) {
2624 				ASSERT3U(attr->za_integer_length, ==,
2625 				    sizeof (uint64_t));
2626 				ASSERT3U(attr->za_num_integers, ==, 1);
2627 
2628 				err = dsl_dataset_hold_obj(dp,
2629 				    attr->za_first_integer, FTAG, &ds);
2630 				if (err != 0)
2631 					break;
2632 				err = dcp->dc_func(dp, ds, dcp->dc_arg);
2633 				dsl_dataset_rele(ds, FTAG);
2634 				if (err != 0)
2635 					break;
2636 			}
2637 			zap_cursor_fini(&zc);
2638 		}
2639 	}
2640 
2641 	kmem_free(attr, sizeof (zap_attribute_t));
2642 
2643 	if (err != 0) {
2644 		dsl_dir_rele(dd, FTAG);
2645 		goto out;
2646 	}
2647 
2648 	/*
2649 	 * Apply to self.
2650 	 */
2651 	err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
2652 
2653 	/*
2654 	 * Note: we hold the dir while calling dsl_dataset_hold_obj() so
2655 	 * that the dir will remain cached, and we won't have to re-instantiate
2656 	 * it (which could be expensive due to finding its name via
2657 	 * zap_value_search()).
2658 	 */
2659 	dsl_dir_rele(dd, FTAG);
2660 	if (err != 0)
2661 		goto out;
2662 	err = dcp->dc_func(dp, ds, dcp->dc_arg);
2663 	dsl_dataset_rele(ds, FTAG);
2664 
2665 out:
2666 	if (err != 0) {
2667 		mutex_enter(dcp->dc_error_lock);
2668 		/* only keep first error */
2669 		if (*dcp->dc_error == 0)
2670 			*dcp->dc_error = err;
2671 		mutex_exit(dcp->dc_error_lock);
2672 	}
2673 
2674 	if (dcp->dc_ddname != NULL)
2675 		spa_strfree(dcp->dc_ddname);
2676 	kmem_free(dcp, sizeof (*dcp));
2677 }
2678 
2679 static void
2680 dmu_objset_find_dp_cb(void *arg)
2681 {
2682 	dmu_objset_find_ctx_t *dcp = arg;
2683 	dsl_pool_t *dp = dcp->dc_dp;
2684 
2685 	/*
2686 	 * We need to get a pool_config_lock here, as there are several
2687 	 * asssert(pool_config_held) down the stack. Getting a lock via
2688 	 * dsl_pool_config_enter is risky, as it might be stalled by a
2689 	 * pending writer. This would deadlock, as the write lock can
2690 	 * only be granted when our parent thread gives up the lock.
2691 	 * The _prio interface gives us priority over a pending writer.
2692 	 */
2693 	dsl_pool_config_enter_prio(dp, FTAG);
2694 
2695 	dmu_objset_find_dp_impl(dcp);
2696 
2697 	dsl_pool_config_exit(dp, FTAG);
2698 }
2699 
2700 /*
2701  * Find objsets under and including ddobj, call func(ds) on each.
2702  * The order for the enumeration is completely undefined.
2703  * func is called with dsl_pool_config held.
2704  */
2705 int
2706 dmu_objset_find_dp(dsl_pool_t *dp, uint64_t ddobj,
2707     int func(dsl_pool_t *, dsl_dataset_t *, void *), void *arg, int flags)
2708 {
2709 	int error = 0;
2710 	taskq_t *tq = NULL;
2711 	int ntasks;
2712 	dmu_objset_find_ctx_t *dcp;
2713 	kmutex_t err_lock;
2714 
2715 	mutex_init(&err_lock, NULL, MUTEX_DEFAULT, NULL);
2716 	dcp = kmem_alloc(sizeof (*dcp), KM_SLEEP);
2717 	dcp->dc_tq = NULL;
2718 	dcp->dc_dp = dp;
2719 	dcp->dc_ddobj = ddobj;
2720 	dcp->dc_ddname = NULL;
2721 	dcp->dc_func = func;
2722 	dcp->dc_arg = arg;
2723 	dcp->dc_flags = flags;
2724 	dcp->dc_error_lock = &err_lock;
2725 	dcp->dc_error = &error;
2726 
2727 	if ((flags & DS_FIND_SERIALIZE) || dsl_pool_config_held_writer(dp)) {
2728 		/*
2729 		 * In case a write lock is held we can't make use of
2730 		 * parallelism, as down the stack of the worker threads
2731 		 * the lock is asserted via dsl_pool_config_held.
2732 		 * In case of a read lock this is solved by getting a read
2733 		 * lock in each worker thread, which isn't possible in case
2734 		 * of a writer lock. So we fall back to the synchronous path
2735 		 * here.
2736 		 * In the future it might be possible to get some magic into
2737 		 * dsl_pool_config_held in a way that it returns true for
2738 		 * the worker threads so that a single lock held from this
2739 		 * thread suffices. For now, stay single threaded.
2740 		 */
2741 		dmu_objset_find_dp_impl(dcp);
2742 		mutex_destroy(&err_lock);
2743 
2744 		return (error);
2745 	}
2746 
2747 	ntasks = dmu_find_threads;
2748 	if (ntasks == 0)
2749 		ntasks = vdev_count_leaves(dp->dp_spa) * 4;
2750 	tq = taskq_create("dmu_objset_find", ntasks, minclsyspri, ntasks,
2751 	    INT_MAX, 0);
2752 	if (tq == NULL) {
2753 		kmem_free(dcp, sizeof (*dcp));
2754 		mutex_destroy(&err_lock);
2755 
2756 		return (SET_ERROR(ENOMEM));
2757 	}
2758 	dcp->dc_tq = tq;
2759 
2760 	/* dcp will be freed by task */
2761 	(void) taskq_dispatch(tq, dmu_objset_find_dp_cb, dcp, TQ_SLEEP);
2762 
2763 	/*
2764 	 * PORTING: this code relies on the property of taskq_wait to wait
2765 	 * until no more tasks are queued and no more tasks are active. As
2766 	 * we always queue new tasks from within other tasks, task_wait
2767 	 * reliably waits for the full recursion to finish, even though we
2768 	 * enqueue new tasks after taskq_wait has been called.
2769 	 * On platforms other than illumos, taskq_wait may not have this
2770 	 * property.
2771 	 */
2772 	taskq_wait(tq);
2773 	taskq_destroy(tq);
2774 	mutex_destroy(&err_lock);
2775 
2776 	return (error);
2777 }
2778 
2779 /*
2780  * Find all objsets under name, and for each, call 'func(child_name, arg)'.
2781  * The dp_config_rwlock must not be held when this is called, and it
2782  * will not be held when the callback is called.
2783  * Therefore this function should only be used when the pool is not changing
2784  * (e.g. in syncing context), or the callback can deal with the possible races.
2785  */
2786 static int
2787 dmu_objset_find_impl(spa_t *spa, const char *name,
2788     int func(const char *, void *), void *arg, int flags)
2789 {
2790 	dsl_dir_t *dd;
2791 	dsl_pool_t *dp = spa_get_dsl(spa);
2792 	dsl_dataset_t *ds;
2793 	zap_cursor_t zc;
2794 	zap_attribute_t *attr;
2795 	char *child;
2796 	uint64_t thisobj;
2797 	int err;
2798 
2799 	dsl_pool_config_enter(dp, FTAG);
2800 
2801 	err = dsl_dir_hold(dp, name, FTAG, &dd, NULL);
2802 	if (err != 0) {
2803 		dsl_pool_config_exit(dp, FTAG);
2804 		return (err);
2805 	}
2806 
2807 	/* Don't visit hidden ($MOS & $ORIGIN) objsets. */
2808 	if (dd->dd_myname[0] == '$') {
2809 		dsl_dir_rele(dd, FTAG);
2810 		dsl_pool_config_exit(dp, FTAG);
2811 		return (0);
2812 	}
2813 
2814 	thisobj = dsl_dir_phys(dd)->dd_head_dataset_obj;
2815 	attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
2816 
2817 	/*
2818 	 * Iterate over all children.
2819 	 */
2820 	if (flags & DS_FIND_CHILDREN) {
2821 		for (zap_cursor_init(&zc, dp->dp_meta_objset,
2822 		    dsl_dir_phys(dd)->dd_child_dir_zapobj);
2823 		    zap_cursor_retrieve(&zc, attr) == 0;
2824 		    (void) zap_cursor_advance(&zc)) {
2825 			ASSERT3U(attr->za_integer_length, ==,
2826 			    sizeof (uint64_t));
2827 			ASSERT3U(attr->za_num_integers, ==, 1);
2828 
2829 			child = kmem_asprintf("%s/%s", name, attr->za_name);
2830 			dsl_pool_config_exit(dp, FTAG);
2831 			err = dmu_objset_find_impl(spa, child,
2832 			    func, arg, flags);
2833 			dsl_pool_config_enter(dp, FTAG);
2834 			strfree(child);
2835 			if (err != 0)
2836 				break;
2837 		}
2838 		zap_cursor_fini(&zc);
2839 
2840 		if (err != 0) {
2841 			dsl_dir_rele(dd, FTAG);
2842 			dsl_pool_config_exit(dp, FTAG);
2843 			kmem_free(attr, sizeof (zap_attribute_t));
2844 			return (err);
2845 		}
2846 	}
2847 
2848 	/*
2849 	 * Iterate over all snapshots.
2850 	 */
2851 	if (flags & DS_FIND_SNAPSHOTS) {
2852 		err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
2853 
2854 		if (err == 0) {
2855 			uint64_t snapobj;
2856 
2857 			snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
2858 			dsl_dataset_rele(ds, FTAG);
2859 
2860 			for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
2861 			    zap_cursor_retrieve(&zc, attr) == 0;
2862 			    (void) zap_cursor_advance(&zc)) {
2863 				ASSERT3U(attr->za_integer_length, ==,
2864 				    sizeof (uint64_t));
2865 				ASSERT3U(attr->za_num_integers, ==, 1);
2866 
2867 				child = kmem_asprintf("%s@%s",
2868 				    name, attr->za_name);
2869 				dsl_pool_config_exit(dp, FTAG);
2870 				err = func(child, arg);
2871 				dsl_pool_config_enter(dp, FTAG);
2872 				strfree(child);
2873 				if (err != 0)
2874 					break;
2875 			}
2876 			zap_cursor_fini(&zc);
2877 		}
2878 	}
2879 
2880 	dsl_dir_rele(dd, FTAG);
2881 	kmem_free(attr, sizeof (zap_attribute_t));
2882 	dsl_pool_config_exit(dp, FTAG);
2883 
2884 	if (err != 0)
2885 		return (err);
2886 
2887 	/* Apply to self. */
2888 	return (func(name, arg));
2889 }
2890 
2891 /*
2892  * See comment above dmu_objset_find_impl().
2893  */
2894 int
2895 dmu_objset_find(char *name, int func(const char *, void *), void *arg,
2896     int flags)
2897 {
2898 	spa_t *spa;
2899 	int error;
2900 
2901 	error = spa_open(name, &spa, FTAG);
2902 	if (error != 0)
2903 		return (error);
2904 	error = dmu_objset_find_impl(spa, name, func, arg, flags);
2905 	spa_close(spa, FTAG);
2906 	return (error);
2907 }
2908 
2909 boolean_t
2910 dmu_objset_incompatible_encryption_version(objset_t *os)
2911 {
2912 	return (dsl_dir_incompatible_encryption_version(
2913 	    os->os_dsl_dataset->ds_dir));
2914 }
2915 
2916 void
2917 dmu_objset_set_user(objset_t *os, void *user_ptr)
2918 {
2919 	ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
2920 	os->os_user_ptr = user_ptr;
2921 }
2922 
2923 void *
2924 dmu_objset_get_user(objset_t *os)
2925 {
2926 	ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
2927 	return (os->os_user_ptr);
2928 }
2929 
2930 /*
2931  * Determine name of filesystem, given name of snapshot.
2932  * buf must be at least ZFS_MAX_DATASET_NAME_LEN bytes
2933  */
2934 int
2935 dmu_fsname(const char *snapname, char *buf)
2936 {
2937 	char *atp = strchr(snapname, '@');
2938 	if (atp == NULL)
2939 		return (SET_ERROR(EINVAL));
2940 	if (atp - snapname >= ZFS_MAX_DATASET_NAME_LEN)
2941 		return (SET_ERROR(ENAMETOOLONG));
2942 	(void) strlcpy(buf, snapname, atp - snapname + 1);
2943 	return (0);
2944 }
2945 
2946 /*
2947  * Call when we think we're going to write/free space in open context to track
2948  * the amount of dirty data in the open txg, which is also the amount
2949  * of memory that can not be evicted until this txg syncs.
2950  */
2951 void
2952 dmu_objset_willuse_space(objset_t *os, int64_t space, dmu_tx_t *tx)
2953 {
2954 	dsl_dataset_t *ds = os->os_dsl_dataset;
2955 	int64_t aspace = spa_get_worst_case_asize(os->os_spa, space);
2956 
2957 	if (ds != NULL) {
2958 		dsl_dir_willuse_space(ds->ds_dir, aspace, tx);
2959 		dsl_pool_dirty_space(dmu_tx_pool(tx), space, tx);
2960 	}
2961 }
2962