xref: /freebsd/sys/contrib/openzfs/module/zfs/dnode_sync.c (revision 62a52c15422470f97fc7b311d89c83f910bcc1b1)
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 https://opensource.org/licenses/CDDL-1.0.
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, 2020 by Delphix. All rights reserved.
25  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
26  * Copyright 2020 Oxide Computer Company
27  */
28 
29 #include <sys/zfs_context.h>
30 #include <sys/dbuf.h>
31 #include <sys/dnode.h>
32 #include <sys/dmu.h>
33 #include <sys/dmu_tx.h>
34 #include <sys/dmu_objset.h>
35 #include <sys/dmu_recv.h>
36 #include <sys/dsl_dataset.h>
37 #include <sys/spa.h>
38 #include <sys/range_tree.h>
39 #include <sys/zfeature.h>
40 
41 static void
42 dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx)
43 {
44 	dmu_buf_impl_t *db;
45 	int txgoff = tx->tx_txg & TXG_MASK;
46 	int nblkptr = dn->dn_phys->dn_nblkptr;
47 	int old_toplvl = dn->dn_phys->dn_nlevels - 1;
48 	int new_level = dn->dn_next_nlevels[txgoff];
49 	int i;
50 
51 	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
52 
53 	/* this dnode can't be paged out because it's dirty */
54 	ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
55 	ASSERT(new_level > 1 && dn->dn_phys->dn_nlevels > 0);
56 
57 	db = dbuf_hold_level(dn, dn->dn_phys->dn_nlevels, 0, FTAG);
58 	ASSERT(db != NULL);
59 
60 	dn->dn_phys->dn_nlevels = new_level;
61 	dprintf("os=%p obj=%llu, increase to %d\n", dn->dn_objset,
62 	    (u_longlong_t)dn->dn_object, dn->dn_phys->dn_nlevels);
63 
64 	/*
65 	 * Lock ordering requires that we hold the children's db_mutexes (by
66 	 * calling dbuf_find()) before holding the parent's db_rwlock.  The lock
67 	 * order is imposed by dbuf_read's steps of "grab the lock to protect
68 	 * db_parent, get db_parent, hold db_parent's db_rwlock".
69 	 */
70 	dmu_buf_impl_t *children[DN_MAX_NBLKPTR];
71 	ASSERT3U(nblkptr, <=, DN_MAX_NBLKPTR);
72 	for (i = 0; i < nblkptr; i++) {
73 		children[i] = dbuf_find(dn->dn_objset, dn->dn_object,
74 		    old_toplvl, i, NULL);
75 	}
76 
77 	/* transfer dnode's block pointers to new indirect block */
78 	(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED|DB_RF_HAVESTRUCT);
79 	if (dn->dn_dbuf != NULL)
80 		rw_enter(&dn->dn_dbuf->db_rwlock, RW_WRITER);
81 	rw_enter(&db->db_rwlock, RW_WRITER);
82 	ASSERT(db->db.db_data);
83 	ASSERT(arc_released(db->db_buf));
84 	ASSERT3U(sizeof (blkptr_t) * nblkptr, <=, db->db.db_size);
85 	memcpy(db->db.db_data, dn->dn_phys->dn_blkptr,
86 	    sizeof (blkptr_t) * nblkptr);
87 	arc_buf_freeze(db->db_buf);
88 
89 	/* set dbuf's parent pointers to new indirect buf */
90 	for (i = 0; i < nblkptr; i++) {
91 		dmu_buf_impl_t *child = children[i];
92 
93 		if (child == NULL)
94 			continue;
95 #ifdef	ZFS_DEBUG
96 		DB_DNODE_ENTER(child);
97 		ASSERT3P(DB_DNODE(child), ==, dn);
98 		DB_DNODE_EXIT(child);
99 #endif	/* DEBUG */
100 		if (child->db_parent && child->db_parent != dn->dn_dbuf) {
101 			ASSERT(child->db_parent->db_level == db->db_level);
102 			ASSERT(child->db_blkptr !=
103 			    &dn->dn_phys->dn_blkptr[child->db_blkid]);
104 			mutex_exit(&child->db_mtx);
105 			continue;
106 		}
107 		ASSERT(child->db_parent == NULL ||
108 		    child->db_parent == dn->dn_dbuf);
109 
110 		child->db_parent = db;
111 		dbuf_add_ref(db, child);
112 		if (db->db.db_data)
113 			child->db_blkptr = (blkptr_t *)db->db.db_data + i;
114 		else
115 			child->db_blkptr = NULL;
116 		dprintf_dbuf_bp(child, child->db_blkptr,
117 		    "changed db_blkptr to new indirect %s", "");
118 
119 		mutex_exit(&child->db_mtx);
120 	}
121 
122 	memset(dn->dn_phys->dn_blkptr, 0, sizeof (blkptr_t) * nblkptr);
123 
124 	rw_exit(&db->db_rwlock);
125 	if (dn->dn_dbuf != NULL)
126 		rw_exit(&dn->dn_dbuf->db_rwlock);
127 
128 	dbuf_rele(db, FTAG);
129 
130 	rw_exit(&dn->dn_struct_rwlock);
131 }
132 
133 static void
134 free_blocks(dnode_t *dn, blkptr_t *bp, int num, dmu_tx_t *tx)
135 {
136 	dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
137 	uint64_t bytesfreed = 0;
138 
139 	dprintf("ds=%p obj=%llx num=%d\n", ds, (u_longlong_t)dn->dn_object,
140 	    num);
141 
142 	for (int i = 0; i < num; i++, bp++) {
143 		if (BP_IS_HOLE(bp))
144 			continue;
145 
146 		bytesfreed += dsl_dataset_block_kill(ds, bp, tx, B_FALSE);
147 		ASSERT3U(bytesfreed, <=, DN_USED_BYTES(dn->dn_phys));
148 
149 		/*
150 		 * Save some useful information on the holes being
151 		 * punched, including logical size, type, and indirection
152 		 * level. Retaining birth time enables detection of when
153 		 * holes are punched for reducing the number of free
154 		 * records transmitted during a zfs send.
155 		 */
156 
157 		uint64_t lsize = BP_GET_LSIZE(bp);
158 		dmu_object_type_t type = BP_GET_TYPE(bp);
159 		uint64_t lvl = BP_GET_LEVEL(bp);
160 
161 		memset(bp, 0, sizeof (blkptr_t));
162 
163 		if (spa_feature_is_active(dn->dn_objset->os_spa,
164 		    SPA_FEATURE_HOLE_BIRTH)) {
165 			BP_SET_LSIZE(bp, lsize);
166 			BP_SET_TYPE(bp, type);
167 			BP_SET_LEVEL(bp, lvl);
168 			BP_SET_BIRTH(bp, dmu_tx_get_txg(tx), 0);
169 		}
170 	}
171 	dnode_diduse_space(dn, -bytesfreed);
172 }
173 
174 #ifdef ZFS_DEBUG
175 static void
176 free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx)
177 {
178 	uint64_t off, num, i, j;
179 	unsigned int epbs;
180 	int err;
181 	uint64_t txg = tx->tx_txg;
182 	dnode_t *dn;
183 
184 	DB_DNODE_ENTER(db);
185 	dn = DB_DNODE(db);
186 	epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
187 	off = start - (db->db_blkid << epbs);
188 	num = end - start + 1;
189 
190 	ASSERT3U(dn->dn_phys->dn_indblkshift, >=, SPA_BLKPTRSHIFT);
191 	ASSERT3U(end + 1, >=, start);
192 	ASSERT3U(start, >=, (db->db_blkid << epbs));
193 	ASSERT3U(db->db_level, >, 0);
194 	ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift);
195 	ASSERT3U(off+num, <=, db->db.db_size >> SPA_BLKPTRSHIFT);
196 	ASSERT(db->db_blkptr != NULL);
197 
198 	for (i = off; i < off+num; i++) {
199 		uint64_t *buf;
200 		dmu_buf_impl_t *child;
201 		dbuf_dirty_record_t *dr;
202 
203 		ASSERT(db->db_level == 1);
204 
205 		rw_enter(&dn->dn_struct_rwlock, RW_READER);
206 		err = dbuf_hold_impl(dn, db->db_level - 1,
207 		    (db->db_blkid << epbs) + i, TRUE, FALSE, FTAG, &child);
208 		rw_exit(&dn->dn_struct_rwlock);
209 		if (err == ENOENT)
210 			continue;
211 		ASSERT(err == 0);
212 		ASSERT(child->db_level == 0);
213 		dr = dbuf_find_dirty_eq(child, txg);
214 
215 		/* data_old better be zeroed */
216 		if (dr) {
217 			buf = dr->dt.dl.dr_data->b_data;
218 			for (j = 0; j < child->db.db_size >> 3; j++) {
219 				if (buf[j] != 0) {
220 					panic("freed data not zero: "
221 					    "child=%p i=%llu off=%llu "
222 					    "num=%llu\n",
223 					    (void *)child, (u_longlong_t)i,
224 					    (u_longlong_t)off,
225 					    (u_longlong_t)num);
226 				}
227 			}
228 		}
229 
230 		/*
231 		 * db_data better be zeroed unless it's dirty in a
232 		 * future txg.
233 		 */
234 		mutex_enter(&child->db_mtx);
235 		buf = child->db.db_data;
236 		if (buf != NULL && child->db_state != DB_FILL &&
237 		    list_is_empty(&child->db_dirty_records)) {
238 			for (j = 0; j < child->db.db_size >> 3; j++) {
239 				if (buf[j] != 0) {
240 					panic("freed data not zero: "
241 					    "child=%p i=%llu off=%llu "
242 					    "num=%llu\n",
243 					    (void *)child, (u_longlong_t)i,
244 					    (u_longlong_t)off,
245 					    (u_longlong_t)num);
246 				}
247 			}
248 		}
249 		mutex_exit(&child->db_mtx);
250 
251 		dbuf_rele(child, FTAG);
252 	}
253 	DB_DNODE_EXIT(db);
254 }
255 #endif
256 
257 /*
258  * We don't usually free the indirect blocks here.  If in one txg we have a
259  * free_range and a write to the same indirect block, it's important that we
260  * preserve the hole's birth times. Therefore, we don't free any any indirect
261  * blocks in free_children().  If an indirect block happens to turn into all
262  * holes, it will be freed by dbuf_write_children_ready, which happens at a
263  * point in the syncing process where we know for certain the contents of the
264  * indirect block.
265  *
266  * However, if we're freeing a dnode, its space accounting must go to zero
267  * before we actually try to free the dnode, or we will trip an assertion. In
268  * addition, we know the case described above cannot occur, because the dnode is
269  * being freed.  Therefore, we free the indirect blocks immediately in that
270  * case.
271  */
272 static void
273 free_children(dmu_buf_impl_t *db, uint64_t blkid, uint64_t nblks,
274     boolean_t free_indirects, dmu_tx_t *tx)
275 {
276 	dnode_t *dn;
277 	blkptr_t *bp;
278 	dmu_buf_impl_t *subdb;
279 	uint64_t start, end, dbstart, dbend;
280 	unsigned int epbs, shift, i;
281 
282 	/*
283 	 * There is a small possibility that this block will not be cached:
284 	 *   1 - if level > 1 and there are no children with level <= 1
285 	 *   2 - if this block was evicted since we read it from
286 	 *	 dmu_tx_hold_free().
287 	 */
288 	if (db->db_state != DB_CACHED)
289 		(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
290 
291 	/*
292 	 * If we modify this indirect block, and we are not freeing the
293 	 * dnode (!free_indirects), then this indirect block needs to get
294 	 * written to disk by dbuf_write().  If it is dirty, we know it will
295 	 * be written (otherwise, we would have incorrect on-disk state
296 	 * because the space would be freed but still referenced by the BP
297 	 * in this indirect block).  Therefore we VERIFY that it is
298 	 * dirty.
299 	 *
300 	 * Our VERIFY covers some cases that do not actually have to be
301 	 * dirty, but the open-context code happens to dirty.  E.g. if the
302 	 * blocks we are freeing are all holes, because in that case, we
303 	 * are only freeing part of this indirect block, so it is an
304 	 * ancestor of the first or last block to be freed.  The first and
305 	 * last L1 indirect blocks are always dirtied by dnode_free_range().
306 	 */
307 	db_lock_type_t dblt = dmu_buf_lock_parent(db, RW_READER, FTAG);
308 	VERIFY(BP_GET_FILL(db->db_blkptr) == 0 || db->db_dirtycnt > 0);
309 	dmu_buf_unlock_parent(db, dblt, FTAG);
310 
311 	dbuf_release_bp(db);
312 	bp = db->db.db_data;
313 
314 	DB_DNODE_ENTER(db);
315 	dn = DB_DNODE(db);
316 	epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
317 	ASSERT3U(epbs, <, 31);
318 	shift = (db->db_level - 1) * epbs;
319 	dbstart = db->db_blkid << epbs;
320 	start = blkid >> shift;
321 	if (dbstart < start) {
322 		bp += start - dbstart;
323 	} else {
324 		start = dbstart;
325 	}
326 	dbend = ((db->db_blkid + 1) << epbs) - 1;
327 	end = (blkid + nblks - 1) >> shift;
328 	if (dbend <= end)
329 		end = dbend;
330 
331 	ASSERT3U(start, <=, end);
332 
333 	if (db->db_level == 1) {
334 		FREE_VERIFY(db, start, end, tx);
335 		rw_enter(&db->db_rwlock, RW_WRITER);
336 		free_blocks(dn, bp, end - start + 1, tx);
337 		rw_exit(&db->db_rwlock);
338 	} else {
339 		for (uint64_t id = start; id <= end; id++, bp++) {
340 			if (BP_IS_HOLE(bp))
341 				continue;
342 			rw_enter(&dn->dn_struct_rwlock, RW_READER);
343 			VERIFY0(dbuf_hold_impl(dn, db->db_level - 1,
344 			    id, TRUE, FALSE, FTAG, &subdb));
345 			rw_exit(&dn->dn_struct_rwlock);
346 			ASSERT3P(bp, ==, subdb->db_blkptr);
347 
348 			free_children(subdb, blkid, nblks, free_indirects, tx);
349 			dbuf_rele(subdb, FTAG);
350 		}
351 	}
352 
353 	if (free_indirects) {
354 		rw_enter(&db->db_rwlock, RW_WRITER);
355 		for (i = 0, bp = db->db.db_data; i < 1 << epbs; i++, bp++)
356 			ASSERT(BP_IS_HOLE(bp));
357 		memset(db->db.db_data, 0, db->db.db_size);
358 		free_blocks(dn, db->db_blkptr, 1, tx);
359 		rw_exit(&db->db_rwlock);
360 	}
361 
362 	DB_DNODE_EXIT(db);
363 	arc_buf_freeze(db->db_buf);
364 }
365 
366 /*
367  * Traverse the indicated range of the provided file
368  * and "free" all the blocks contained there.
369  */
370 static void
371 dnode_sync_free_range_impl(dnode_t *dn, uint64_t blkid, uint64_t nblks,
372     boolean_t free_indirects, dmu_tx_t *tx)
373 {
374 	blkptr_t *bp = dn->dn_phys->dn_blkptr;
375 	int dnlevel = dn->dn_phys->dn_nlevels;
376 	boolean_t trunc = B_FALSE;
377 
378 	if (blkid > dn->dn_phys->dn_maxblkid)
379 		return;
380 
381 	ASSERT(dn->dn_phys->dn_maxblkid < UINT64_MAX);
382 	if (blkid + nblks > dn->dn_phys->dn_maxblkid) {
383 		nblks = dn->dn_phys->dn_maxblkid - blkid + 1;
384 		trunc = B_TRUE;
385 	}
386 
387 	/* There are no indirect blocks in the object */
388 	if (dnlevel == 1) {
389 		if (blkid >= dn->dn_phys->dn_nblkptr) {
390 			/* this range was never made persistent */
391 			return;
392 		}
393 		ASSERT3U(blkid + nblks, <=, dn->dn_phys->dn_nblkptr);
394 		free_blocks(dn, bp + blkid, nblks, tx);
395 	} else {
396 		int shift = (dnlevel - 1) *
397 		    (dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT);
398 		int start = blkid >> shift;
399 		int end = (blkid + nblks - 1) >> shift;
400 		dmu_buf_impl_t *db;
401 
402 		ASSERT(start < dn->dn_phys->dn_nblkptr);
403 		bp += start;
404 		for (int i = start; i <= end; i++, bp++) {
405 			if (BP_IS_HOLE(bp))
406 				continue;
407 			rw_enter(&dn->dn_struct_rwlock, RW_READER);
408 			VERIFY0(dbuf_hold_impl(dn, dnlevel - 1, i,
409 			    TRUE, FALSE, FTAG, &db));
410 			rw_exit(&dn->dn_struct_rwlock);
411 			free_children(db, blkid, nblks, free_indirects, tx);
412 			dbuf_rele(db, FTAG);
413 		}
414 	}
415 
416 	/*
417 	 * Do not truncate the maxblkid if we are performing a raw
418 	 * receive. The raw receive sets the maxblkid manually and
419 	 * must not be overridden. Usually, the last DRR_FREE record
420 	 * will be at the maxblkid, because the source system sets
421 	 * the maxblkid when truncating. However, if the last block
422 	 * was freed by overwriting with zeros and being compressed
423 	 * away to a hole, the source system will generate a DRR_FREE
424 	 * record while leaving the maxblkid after the end of that
425 	 * record. In this case we need to leave the maxblkid as
426 	 * indicated in the DRR_OBJECT record, so that it matches the
427 	 * source system, ensuring that the cryptographic hashes will
428 	 * match.
429 	 */
430 	if (trunc && !dn->dn_objset->os_raw_receive) {
431 		uint64_t off __maybe_unused;
432 		dn->dn_phys->dn_maxblkid = blkid == 0 ? 0 : blkid - 1;
433 
434 		off = (dn->dn_phys->dn_maxblkid + 1) *
435 		    (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT);
436 		ASSERT(off < dn->dn_phys->dn_maxblkid ||
437 		    dn->dn_phys->dn_maxblkid == 0 ||
438 		    dnode_next_offset(dn, 0, &off, 1, 1, 0) != 0);
439 	}
440 }
441 
442 typedef struct dnode_sync_free_range_arg {
443 	dnode_t *dsfra_dnode;
444 	dmu_tx_t *dsfra_tx;
445 	boolean_t dsfra_free_indirects;
446 } dnode_sync_free_range_arg_t;
447 
448 static void
449 dnode_sync_free_range(void *arg, uint64_t blkid, uint64_t nblks)
450 {
451 	dnode_sync_free_range_arg_t *dsfra = arg;
452 	dnode_t *dn = dsfra->dsfra_dnode;
453 
454 	mutex_exit(&dn->dn_mtx);
455 	dnode_sync_free_range_impl(dn, blkid, nblks,
456 	    dsfra->dsfra_free_indirects, dsfra->dsfra_tx);
457 	mutex_enter(&dn->dn_mtx);
458 }
459 
460 /*
461  * Try to kick all the dnode's dbufs out of the cache...
462  */
463 void
464 dnode_evict_dbufs(dnode_t *dn)
465 {
466 	dmu_buf_impl_t *db_marker;
467 	dmu_buf_impl_t *db, *db_next;
468 
469 	db_marker = kmem_alloc(sizeof (dmu_buf_impl_t), KM_SLEEP);
470 
471 	mutex_enter(&dn->dn_dbufs_mtx);
472 	for (db = avl_first(&dn->dn_dbufs); db != NULL; db = db_next) {
473 
474 #ifdef	ZFS_DEBUG
475 		DB_DNODE_ENTER(db);
476 		ASSERT3P(DB_DNODE(db), ==, dn);
477 		DB_DNODE_EXIT(db);
478 #endif	/* DEBUG */
479 
480 		mutex_enter(&db->db_mtx);
481 		if (db->db_state != DB_EVICTING &&
482 		    zfs_refcount_is_zero(&db->db_holds)) {
483 			db_marker->db_level = db->db_level;
484 			db_marker->db_blkid = db->db_blkid;
485 			/*
486 			 * Insert a MARKER node with the same level and blkid.
487 			 * And to resolve any ties in dbuf_compare() use the
488 			 * pointer of the dbuf that we are evicting. Pass the
489 			 * address in db_parent.
490 			 */
491 			db_marker->db_state = DB_MARKER;
492 			db_marker->db_parent = (void *)((uintptr_t)db - 1);
493 			avl_insert_here(&dn->dn_dbufs, db_marker, db,
494 			    AVL_BEFORE);
495 
496 			/*
497 			 * We need to use the "marker" dbuf rather than
498 			 * simply getting the next dbuf, because
499 			 * dbuf_destroy() may actually remove multiple dbufs.
500 			 * It can call itself recursively on the parent dbuf,
501 			 * which may also be removed from dn_dbufs.  The code
502 			 * flow would look like:
503 			 *
504 			 * dbuf_destroy():
505 			 *   dnode_rele_and_unlock(parent_dbuf, evicting=TRUE):
506 			 *	if (!cacheable || pending_evict)
507 			 *	  dbuf_destroy()
508 			 */
509 			dbuf_destroy(db);
510 
511 			db_next = AVL_NEXT(&dn->dn_dbufs, db_marker);
512 			avl_remove(&dn->dn_dbufs, db_marker);
513 		} else {
514 			db->db_pending_evict = TRUE;
515 			mutex_exit(&db->db_mtx);
516 			db_next = AVL_NEXT(&dn->dn_dbufs, db);
517 		}
518 	}
519 	mutex_exit(&dn->dn_dbufs_mtx);
520 
521 	kmem_free(db_marker, sizeof (dmu_buf_impl_t));
522 
523 	dnode_evict_bonus(dn);
524 }
525 
526 void
527 dnode_evict_bonus(dnode_t *dn)
528 {
529 	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
530 	if (dn->dn_bonus != NULL) {
531 		if (zfs_refcount_is_zero(&dn->dn_bonus->db_holds)) {
532 			mutex_enter(&dn->dn_bonus->db_mtx);
533 			dbuf_destroy(dn->dn_bonus);
534 			dn->dn_bonus = NULL;
535 		} else {
536 			dn->dn_bonus->db_pending_evict = TRUE;
537 		}
538 	}
539 	rw_exit(&dn->dn_struct_rwlock);
540 }
541 
542 static void
543 dnode_undirty_dbufs(list_t *list)
544 {
545 	dbuf_dirty_record_t *dr;
546 
547 	while ((dr = list_head(list))) {
548 		dmu_buf_impl_t *db = dr->dr_dbuf;
549 		uint64_t txg = dr->dr_txg;
550 
551 		if (db->db_level != 0)
552 			dnode_undirty_dbufs(&dr->dt.di.dr_children);
553 
554 		mutex_enter(&db->db_mtx);
555 		/* XXX - use dbuf_undirty()? */
556 		list_remove(list, dr);
557 		ASSERT(list_head(&db->db_dirty_records) == dr);
558 		list_remove_head(&db->db_dirty_records);
559 		ASSERT(list_is_empty(&db->db_dirty_records));
560 		db->db_dirtycnt -= 1;
561 		if (db->db_level == 0) {
562 			ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
563 			    dr->dt.dl.dr_data == db->db_buf);
564 			dbuf_unoverride(dr);
565 		} else {
566 			mutex_destroy(&dr->dt.di.dr_mtx);
567 			list_destroy(&dr->dt.di.dr_children);
568 		}
569 		kmem_free(dr, sizeof (dbuf_dirty_record_t));
570 		dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg, B_FALSE);
571 	}
572 }
573 
574 static void
575 dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)
576 {
577 	int txgoff = tx->tx_txg & TXG_MASK;
578 
579 	ASSERT(dmu_tx_is_syncing(tx));
580 
581 	/*
582 	 * Our contents should have been freed in dnode_sync() by the
583 	 * free range record inserted by the caller of dnode_free().
584 	 */
585 	ASSERT0(DN_USED_BYTES(dn->dn_phys));
586 	ASSERT(BP_IS_HOLE(dn->dn_phys->dn_blkptr));
587 
588 	dnode_undirty_dbufs(&dn->dn_dirty_records[txgoff]);
589 	dnode_evict_dbufs(dn);
590 
591 	/*
592 	 * XXX - It would be nice to assert this, but we may still
593 	 * have residual holds from async evictions from the arc...
594 	 *
595 	 * zfs_obj_to_path() also depends on this being
596 	 * commented out.
597 	 *
598 	 * ASSERT3U(zfs_refcount_count(&dn->dn_holds), ==, 1);
599 	 */
600 
601 	/* Undirty next bits */
602 	dn->dn_next_nlevels[txgoff] = 0;
603 	dn->dn_next_indblkshift[txgoff] = 0;
604 	dn->dn_next_blksz[txgoff] = 0;
605 	dn->dn_next_maxblkid[txgoff] = 0;
606 
607 	/* ASSERT(blkptrs are zero); */
608 	ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
609 	ASSERT(dn->dn_type != DMU_OT_NONE);
610 
611 	ASSERT(dn->dn_free_txg > 0);
612 	if (dn->dn_allocated_txg != dn->dn_free_txg)
613 		dmu_buf_will_dirty(&dn->dn_dbuf->db, tx);
614 	memset(dn->dn_phys, 0, sizeof (dnode_phys_t) * dn->dn_num_slots);
615 	dnode_free_interior_slots(dn);
616 
617 	mutex_enter(&dn->dn_mtx);
618 	dn->dn_type = DMU_OT_NONE;
619 	dn->dn_maxblkid = 0;
620 	dn->dn_allocated_txg = 0;
621 	dn->dn_free_txg = 0;
622 	dn->dn_have_spill = B_FALSE;
623 	dn->dn_num_slots = 1;
624 	mutex_exit(&dn->dn_mtx);
625 
626 	ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
627 
628 	dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
629 	/*
630 	 * Now that we've released our hold, the dnode may
631 	 * be evicted, so we mustn't access it.
632 	 */
633 }
634 
635 /*
636  * Write out the dnode's dirty buffers.
637  * Does not wait for zio completions.
638  */
639 void
640 dnode_sync(dnode_t *dn, dmu_tx_t *tx)
641 {
642 	objset_t *os = dn->dn_objset;
643 	dnode_phys_t *dnp = dn->dn_phys;
644 	int txgoff = tx->tx_txg & TXG_MASK;
645 	list_t *list = &dn->dn_dirty_records[txgoff];
646 	static const dnode_phys_t zerodn __maybe_unused = { 0 };
647 	boolean_t kill_spill = B_FALSE;
648 
649 	ASSERT(dmu_tx_is_syncing(tx));
650 	ASSERT(dnp->dn_type != DMU_OT_NONE || dn->dn_allocated_txg);
651 	ASSERT(dnp->dn_type != DMU_OT_NONE ||
652 	    memcmp(dnp, &zerodn, DNODE_MIN_SIZE) == 0);
653 	DNODE_VERIFY(dn);
654 
655 	ASSERT(dn->dn_dbuf == NULL || arc_released(dn->dn_dbuf->db_buf));
656 
657 	/*
658 	 * Do user accounting if it is enabled and this is not
659 	 * an encrypted receive.
660 	 */
661 	if (dmu_objset_userused_enabled(os) &&
662 	    !DMU_OBJECT_IS_SPECIAL(dn->dn_object) &&
663 	    (!os->os_encrypted || !dmu_objset_is_receiving(os))) {
664 		mutex_enter(&dn->dn_mtx);
665 		dn->dn_oldused = DN_USED_BYTES(dn->dn_phys);
666 		dn->dn_oldflags = dn->dn_phys->dn_flags;
667 		dn->dn_phys->dn_flags |= DNODE_FLAG_USERUSED_ACCOUNTED;
668 		if (dmu_objset_userobjused_enabled(dn->dn_objset))
669 			dn->dn_phys->dn_flags |=
670 			    DNODE_FLAG_USEROBJUSED_ACCOUNTED;
671 		mutex_exit(&dn->dn_mtx);
672 		dmu_objset_userquota_get_ids(dn, B_FALSE, tx);
673 	} else if (!(os->os_encrypted && dmu_objset_is_receiving(os))) {
674 		/*
675 		 * Once we account for it, we should always account for it,
676 		 * except for the case of a raw receive. We will not be able
677 		 * to account for it until the receiving dataset has been
678 		 * mounted.
679 		 */
680 		ASSERT(!(dn->dn_phys->dn_flags &
681 		    DNODE_FLAG_USERUSED_ACCOUNTED));
682 		ASSERT(!(dn->dn_phys->dn_flags &
683 		    DNODE_FLAG_USEROBJUSED_ACCOUNTED));
684 	}
685 
686 	mutex_enter(&dn->dn_mtx);
687 	if (dn->dn_allocated_txg == tx->tx_txg) {
688 		/* The dnode is newly allocated or reallocated */
689 		if (dnp->dn_type == DMU_OT_NONE) {
690 			/* this is a first alloc, not a realloc */
691 			dnp->dn_nlevels = 1;
692 			dnp->dn_nblkptr = dn->dn_nblkptr;
693 		}
694 
695 		dnp->dn_type = dn->dn_type;
696 		dnp->dn_bonustype = dn->dn_bonustype;
697 		dnp->dn_bonuslen = dn->dn_bonuslen;
698 	}
699 
700 	dnp->dn_extra_slots = dn->dn_num_slots - 1;
701 
702 	ASSERT(dnp->dn_nlevels > 1 ||
703 	    BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
704 	    BP_IS_EMBEDDED(&dnp->dn_blkptr[0]) ||
705 	    BP_GET_LSIZE(&dnp->dn_blkptr[0]) ==
706 	    dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT);
707 	ASSERT(dnp->dn_nlevels < 2 ||
708 	    BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
709 	    BP_GET_LSIZE(&dnp->dn_blkptr[0]) == 1 << dnp->dn_indblkshift);
710 
711 	if (dn->dn_next_type[txgoff] != 0) {
712 		dnp->dn_type = dn->dn_type;
713 		dn->dn_next_type[txgoff] = 0;
714 	}
715 
716 	if (dn->dn_next_blksz[txgoff] != 0) {
717 		ASSERT(P2PHASE(dn->dn_next_blksz[txgoff],
718 		    SPA_MINBLOCKSIZE) == 0);
719 		ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
720 		    dn->dn_maxblkid == 0 || list_head(list) != NULL ||
721 		    dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT ==
722 		    dnp->dn_datablkszsec ||
723 		    !range_tree_is_empty(dn->dn_free_ranges[txgoff]));
724 		dnp->dn_datablkszsec =
725 		    dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT;
726 		dn->dn_next_blksz[txgoff] = 0;
727 	}
728 
729 	if (dn->dn_next_bonuslen[txgoff] != 0) {
730 		if (dn->dn_next_bonuslen[txgoff] == DN_ZERO_BONUSLEN)
731 			dnp->dn_bonuslen = 0;
732 		else
733 			dnp->dn_bonuslen = dn->dn_next_bonuslen[txgoff];
734 		ASSERT(dnp->dn_bonuslen <=
735 		    DN_SLOTS_TO_BONUSLEN(dnp->dn_extra_slots + 1));
736 		dn->dn_next_bonuslen[txgoff] = 0;
737 	}
738 
739 	if (dn->dn_next_bonustype[txgoff] != 0) {
740 		ASSERT(DMU_OT_IS_VALID(dn->dn_next_bonustype[txgoff]));
741 		dnp->dn_bonustype = dn->dn_next_bonustype[txgoff];
742 		dn->dn_next_bonustype[txgoff] = 0;
743 	}
744 
745 	boolean_t freeing_dnode = dn->dn_free_txg > 0 &&
746 	    dn->dn_free_txg <= tx->tx_txg;
747 
748 	/*
749 	 * Remove the spill block if we have been explicitly asked to
750 	 * remove it, or if the object is being removed.
751 	 */
752 	if (dn->dn_rm_spillblk[txgoff] || freeing_dnode) {
753 		if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR)
754 			kill_spill = B_TRUE;
755 		dn->dn_rm_spillblk[txgoff] = 0;
756 	}
757 
758 	if (dn->dn_next_indblkshift[txgoff] != 0) {
759 		ASSERT(dnp->dn_nlevels == 1);
760 		dnp->dn_indblkshift = dn->dn_next_indblkshift[txgoff];
761 		dn->dn_next_indblkshift[txgoff] = 0;
762 	}
763 
764 	/*
765 	 * Just take the live (open-context) values for checksum and compress.
766 	 * Strictly speaking it's a future leak, but nothing bad happens if we
767 	 * start using the new checksum or compress algorithm a little early.
768 	 */
769 	dnp->dn_checksum = dn->dn_checksum;
770 	dnp->dn_compress = dn->dn_compress;
771 
772 	mutex_exit(&dn->dn_mtx);
773 
774 	if (kill_spill) {
775 		free_blocks(dn, DN_SPILL_BLKPTR(dn->dn_phys), 1, tx);
776 		mutex_enter(&dn->dn_mtx);
777 		dnp->dn_flags &= ~DNODE_FLAG_SPILL_BLKPTR;
778 		mutex_exit(&dn->dn_mtx);
779 	}
780 
781 	/* process all the "freed" ranges in the file */
782 	if (dn->dn_free_ranges[txgoff] != NULL) {
783 		dnode_sync_free_range_arg_t dsfra;
784 		dsfra.dsfra_dnode = dn;
785 		dsfra.dsfra_tx = tx;
786 		dsfra.dsfra_free_indirects = freeing_dnode;
787 		mutex_enter(&dn->dn_mtx);
788 		if (freeing_dnode) {
789 			ASSERT(range_tree_contains(dn->dn_free_ranges[txgoff],
790 			    0, dn->dn_maxblkid + 1));
791 		}
792 		/*
793 		 * Because dnode_sync_free_range() must drop dn_mtx during its
794 		 * processing, using it as a callback to range_tree_vacate() is
795 		 * not safe.  No other operations (besides destroy) are allowed
796 		 * once range_tree_vacate() has begun, and dropping dn_mtx
797 		 * would leave a window open for another thread to observe that
798 		 * invalid (and unsafe) state.
799 		 */
800 		range_tree_walk(dn->dn_free_ranges[txgoff],
801 		    dnode_sync_free_range, &dsfra);
802 		range_tree_vacate(dn->dn_free_ranges[txgoff], NULL, NULL);
803 		range_tree_destroy(dn->dn_free_ranges[txgoff]);
804 		dn->dn_free_ranges[txgoff] = NULL;
805 		mutex_exit(&dn->dn_mtx);
806 	}
807 
808 	if (freeing_dnode) {
809 		dn->dn_objset->os_freed_dnodes++;
810 		dnode_sync_free(dn, tx);
811 		return;
812 	}
813 
814 	if (dn->dn_num_slots > DNODE_MIN_SLOTS) {
815 		dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
816 		mutex_enter(&ds->ds_lock);
817 		ds->ds_feature_activation[SPA_FEATURE_LARGE_DNODE] =
818 		    (void *)B_TRUE;
819 		mutex_exit(&ds->ds_lock);
820 	}
821 
822 	if (dn->dn_next_nlevels[txgoff]) {
823 		dnode_increase_indirection(dn, tx);
824 		dn->dn_next_nlevels[txgoff] = 0;
825 	}
826 
827 	/*
828 	 * This must be done after dnode_sync_free_range()
829 	 * and dnode_increase_indirection(). See dnode_new_blkid()
830 	 * for an explanation of the high bit being set.
831 	 */
832 	if (dn->dn_next_maxblkid[txgoff]) {
833 		mutex_enter(&dn->dn_mtx);
834 		dnp->dn_maxblkid =
835 		    dn->dn_next_maxblkid[txgoff] & ~DMU_NEXT_MAXBLKID_SET;
836 		dn->dn_next_maxblkid[txgoff] = 0;
837 		mutex_exit(&dn->dn_mtx);
838 	}
839 
840 	if (dn->dn_next_nblkptr[txgoff]) {
841 		/* this should only happen on a realloc */
842 		ASSERT(dn->dn_allocated_txg == tx->tx_txg);
843 		if (dn->dn_next_nblkptr[txgoff] > dnp->dn_nblkptr) {
844 			/* zero the new blkptrs we are gaining */
845 			memset(dnp->dn_blkptr + dnp->dn_nblkptr, 0,
846 			    sizeof (blkptr_t) *
847 			    (dn->dn_next_nblkptr[txgoff] - dnp->dn_nblkptr));
848 #ifdef ZFS_DEBUG
849 		} else {
850 			int i;
851 			ASSERT(dn->dn_next_nblkptr[txgoff] < dnp->dn_nblkptr);
852 			/* the blkptrs we are losing better be unallocated */
853 			for (i = 0; i < dnp->dn_nblkptr; i++) {
854 				if (i >= dn->dn_next_nblkptr[txgoff])
855 					ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[i]));
856 			}
857 #endif
858 		}
859 		mutex_enter(&dn->dn_mtx);
860 		dnp->dn_nblkptr = dn->dn_next_nblkptr[txgoff];
861 		dn->dn_next_nblkptr[txgoff] = 0;
862 		mutex_exit(&dn->dn_mtx);
863 	}
864 
865 	dbuf_sync_list(list, dn->dn_phys->dn_nlevels - 1, tx);
866 
867 	if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
868 		ASSERT3P(list_head(list), ==, NULL);
869 		dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
870 	}
871 
872 	ASSERT3U(dnp->dn_bonuslen, <=, DN_MAX_BONUS_LEN(dnp));
873 
874 	/*
875 	 * Although we have dropped our reference to the dnode, it
876 	 * can't be evicted until its written, and we haven't yet
877 	 * initiated the IO for the dnode's dbuf.  Additionally, the caller
878 	 * has already added a reference to the dnode because it's on the
879 	 * os_synced_dnodes list.
880 	 */
881 }
882