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 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
26 * Copyright (c) 2013, Joyent, Inc. All rights reserved.
27 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
28 */
29
30 #include <sys/zfs_context.h>
31 #include <sys/dmu.h>
32 #include <sys/dmu_send.h>
33 #include <sys/dmu_impl.h>
34 #include <sys/dbuf.h>
35 #include <sys/dmu_objset.h>
36 #include <sys/dsl_dataset.h>
37 #include <sys/dsl_dir.h>
38 #include <sys/dmu_tx.h>
39 #include <sys/spa.h>
40 #include <sys/zio.h>
41 #include <sys/dmu_zfetch.h>
42 #include <sys/sa.h>
43 #include <sys/sa_impl.h>
44 #include <sys/zfeature.h>
45 #include <sys/blkptr.h>
46 #include <sys/range_tree.h>
47
48 /*
49 * Number of times that zfs_free_range() took the slow path while doing
50 * a zfs receive. A nonzero value indicates a potential performance problem.
51 */
52 uint64_t zfs_free_range_recv_miss;
53
54 static void dbuf_destroy(dmu_buf_impl_t *db);
55 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
56 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
57
58 #ifndef __lint
59 extern inline void dmu_buf_init_user(dmu_buf_user_t *dbu,
60 dmu_buf_evict_func_t *evict_func, dmu_buf_t **clear_on_evict_dbufp);
61 #endif /* ! __lint */
62
63 /*
64 * Global data structures and functions for the dbuf cache.
65 */
66 static kmem_cache_t *dbuf_cache;
67 static taskq_t *dbu_evict_taskq;
68
69 /* ARGSUSED */
70 static int
71 dbuf_cons(void *vdb, void *unused, int kmflag)
72 {
73 dmu_buf_impl_t *db = vdb;
74 bzero(db, sizeof (dmu_buf_impl_t));
75
76 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
77 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
78 refcount_create(&db->db_holds);
79
80 return (0);
81 }
82
83 /* ARGSUSED */
84 static void
85 dbuf_dest(void *vdb, void *unused)
86 {
87 dmu_buf_impl_t *db = vdb;
88 mutex_destroy(&db->db_mtx);
89 cv_destroy(&db->db_changed);
90 refcount_destroy(&db->db_holds);
91 }
92
93 /*
94 * dbuf hash table routines
95 */
96 static dbuf_hash_table_t dbuf_hash_table;
97
98 static uint64_t dbuf_hash_count;
99
100 static uint64_t
101 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
102 {
103 uintptr_t osv = (uintptr_t)os;
104 uint64_t crc = -1ULL;
105
106 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
107 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
108 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
109 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
110 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
111 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
112 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
113
114 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
115
116 return (crc);
117 }
118
119 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
120
121 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
122 ((dbuf)->db.db_object == (obj) && \
123 (dbuf)->db_objset == (os) && \
124 (dbuf)->db_level == (level) && \
125 (dbuf)->db_blkid == (blkid))
126
127 dmu_buf_impl_t *
128 dbuf_find(objset_t *os, uint64_t obj, uint8_t level, uint64_t blkid)
129 {
130 dbuf_hash_table_t *h = &dbuf_hash_table;
131 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
132 uint64_t idx = hv & h->hash_table_mask;
133 dmu_buf_impl_t *db;
134
135 mutex_enter(DBUF_HASH_MUTEX(h, idx));
136 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
137 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
138 mutex_enter(&db->db_mtx);
139 if (db->db_state != DB_EVICTING) {
140 mutex_exit(DBUF_HASH_MUTEX(h, idx));
141 return (db);
142 }
143 mutex_exit(&db->db_mtx);
144 }
145 }
146 mutex_exit(DBUF_HASH_MUTEX(h, idx));
147 return (NULL);
148 }
149
150 static dmu_buf_impl_t *
151 dbuf_find_bonus(objset_t *os, uint64_t object)
152 {
153 dnode_t *dn;
154 dmu_buf_impl_t *db = NULL;
155
156 if (dnode_hold(os, object, FTAG, &dn) == 0) {
157 rw_enter(&dn->dn_struct_rwlock, RW_READER);
158 if (dn->dn_bonus != NULL) {
159 db = dn->dn_bonus;
160 mutex_enter(&db->db_mtx);
161 }
162 rw_exit(&dn->dn_struct_rwlock);
163 dnode_rele(dn, FTAG);
164 }
165 return (db);
166 }
167
168 /*
169 * Insert an entry into the hash table. If there is already an element
170 * equal to elem in the hash table, then the already existing element
171 * will be returned and the new element will not be inserted.
172 * Otherwise returns NULL.
173 */
174 static dmu_buf_impl_t *
175 dbuf_hash_insert(dmu_buf_impl_t *db)
176 {
177 dbuf_hash_table_t *h = &dbuf_hash_table;
178 objset_t *os = db->db_objset;
179 uint64_t obj = db->db.db_object;
180 int level = db->db_level;
181 uint64_t blkid = db->db_blkid;
182 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
183 uint64_t idx = hv & h->hash_table_mask;
184 dmu_buf_impl_t *dbf;
185
186 mutex_enter(DBUF_HASH_MUTEX(h, idx));
187 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
188 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
189 mutex_enter(&dbf->db_mtx);
190 if (dbf->db_state != DB_EVICTING) {
191 mutex_exit(DBUF_HASH_MUTEX(h, idx));
192 return (dbf);
193 }
194 mutex_exit(&dbf->db_mtx);
195 }
196 }
197
198 mutex_enter(&db->db_mtx);
199 db->db_hash_next = h->hash_table[idx];
200 h->hash_table[idx] = db;
201 mutex_exit(DBUF_HASH_MUTEX(h, idx));
202 atomic_inc_64(&dbuf_hash_count);
203
204 return (NULL);
205 }
206
207 /*
208 * Remove an entry from the hash table. It must be in the EVICTING state.
209 */
210 static void
211 dbuf_hash_remove(dmu_buf_impl_t *db)
212 {
213 dbuf_hash_table_t *h = &dbuf_hash_table;
214 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object,
215 db->db_level, db->db_blkid);
216 uint64_t idx = hv & h->hash_table_mask;
217 dmu_buf_impl_t *dbf, **dbp;
218
219 /*
220 * We musn't hold db_mtx to maintain lock ordering:
221 * DBUF_HASH_MUTEX > db_mtx.
222 */
223 ASSERT(refcount_is_zero(&db->db_holds));
224 ASSERT(db->db_state == DB_EVICTING);
225 ASSERT(!MUTEX_HELD(&db->db_mtx));
226
227 mutex_enter(DBUF_HASH_MUTEX(h, idx));
228 dbp = &h->hash_table[idx];
229 while ((dbf = *dbp) != db) {
230 dbp = &dbf->db_hash_next;
231 ASSERT(dbf != NULL);
232 }
233 *dbp = db->db_hash_next;
234 db->db_hash_next = NULL;
235 mutex_exit(DBUF_HASH_MUTEX(h, idx));
236 atomic_dec_64(&dbuf_hash_count);
237 }
238
239 static arc_evict_func_t dbuf_do_evict;
240
241 typedef enum {
242 DBVU_EVICTING,
243 DBVU_NOT_EVICTING
244 } dbvu_verify_type_t;
245
246 static void
247 dbuf_verify_user(dmu_buf_impl_t *db, dbvu_verify_type_t verify_type)
248 {
249 #ifdef ZFS_DEBUG
250 int64_t holds;
251
252 if (db->db_user == NULL)
253 return;
254
255 /* Only data blocks support the attachment of user data. */
256 ASSERT(db->db_level == 0);
257
258 /* Clients must resolve a dbuf before attaching user data. */
259 ASSERT(db->db.db_data != NULL);
260 ASSERT3U(db->db_state, ==, DB_CACHED);
261
262 holds = refcount_count(&db->db_holds);
263 if (verify_type == DBVU_EVICTING) {
264 /*
265 * Immediate eviction occurs when holds == dirtycnt.
266 * For normal eviction buffers, holds is zero on
267 * eviction, except when dbuf_fix_old_data() calls
268 * dbuf_clear_data(). However, the hold count can grow
269 * during eviction even though db_mtx is held (see
270 * dmu_bonus_hold() for an example), so we can only
271 * test the generic invariant that holds >= dirtycnt.
272 */
273 ASSERT3U(holds, >=, db->db_dirtycnt);
274 } else {
275 if (db->db_immediate_evict == TRUE)
276 ASSERT3U(holds, >=, db->db_dirtycnt);
277 else
278 ASSERT3U(holds, >, 0);
279 }
280 #endif
281 }
282
283 static void
284 dbuf_evict_user(dmu_buf_impl_t *db)
285 {
286 dmu_buf_user_t *dbu = db->db_user;
287
288 ASSERT(MUTEX_HELD(&db->db_mtx));
289
290 if (dbu == NULL)
291 return;
292
293 dbuf_verify_user(db, DBVU_EVICTING);
294 db->db_user = NULL;
295
296 #ifdef ZFS_DEBUG
297 if (dbu->dbu_clear_on_evict_dbufp != NULL)
298 *dbu->dbu_clear_on_evict_dbufp = NULL;
299 #endif
300
301 /*
302 * Invoke the callback from a taskq to avoid lock order reversals
303 * and limit stack depth.
304 */
305 taskq_dispatch_ent(dbu_evict_taskq, dbu->dbu_evict_func, dbu, 0,
306 &dbu->dbu_tqent);
307 }
308
309 boolean_t
310 dbuf_is_metadata(dmu_buf_impl_t *db)
311 {
312 if (db->db_level > 0) {
313 return (B_TRUE);
314 } else {
315 boolean_t is_metadata;
316
317 DB_DNODE_ENTER(db);
318 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type);
319 DB_DNODE_EXIT(db);
320
321 return (is_metadata);
322 }
323 }
324
325 void
326 dbuf_evict(dmu_buf_impl_t *db)
327 {
328 ASSERT(MUTEX_HELD(&db->db_mtx));
329 ASSERT(db->db_buf == NULL);
330 ASSERT(db->db_data_pending == NULL);
331
332 dbuf_clear(db);
333 dbuf_destroy(db);
334 }
335
336 void
337 dbuf_init(void)
338 {
339 uint64_t hsize = 1ULL << 16;
340 dbuf_hash_table_t *h = &dbuf_hash_table;
341 int i;
342
343 /*
344 * The hash table is big enough to fill all of physical memory
345 * with an average 4K block size. The table will take up
346 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
347 */
348 while (hsize * 4096 < physmem * PAGESIZE)
349 hsize <<= 1;
350
351 retry:
352 h->hash_table_mask = hsize - 1;
353 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
354 if (h->hash_table == NULL) {
355 /* XXX - we should really return an error instead of assert */
356 ASSERT(hsize > (1ULL << 10));
357 hsize >>= 1;
358 goto retry;
359 }
360
361 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
362 sizeof (dmu_buf_impl_t),
363 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
364
365 for (i = 0; i < DBUF_MUTEXES; i++)
366 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
367
368 /*
369 * All entries are queued via taskq_dispatch_ent(), so min/maxalloc
370 * configuration is not required.
371 */
372 dbu_evict_taskq = taskq_create("dbu_evict", 1, minclsyspri, 0, 0, 0);
373 }
374
375 void
376 dbuf_fini(void)
377 {
378 dbuf_hash_table_t *h = &dbuf_hash_table;
379 int i;
380
381 for (i = 0; i < DBUF_MUTEXES; i++)
382 mutex_destroy(&h->hash_mutexes[i]);
383 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
384 kmem_cache_destroy(dbuf_cache);
385 taskq_destroy(dbu_evict_taskq);
386 }
387
388 /*
389 * Other stuff.
390 */
391
392 #ifdef ZFS_DEBUG
393 static void
394 dbuf_verify(dmu_buf_impl_t *db)
395 {
396 dnode_t *dn;
397 dbuf_dirty_record_t *dr;
398
399 ASSERT(MUTEX_HELD(&db->db_mtx));
400
401 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
402 return;
403
404 ASSERT(db->db_objset != NULL);
405 DB_DNODE_ENTER(db);
406 dn = DB_DNODE(db);
407 if (dn == NULL) {
408 ASSERT(db->db_parent == NULL);
409 ASSERT(db->db_blkptr == NULL);
410 } else {
411 ASSERT3U(db->db.db_object, ==, dn->dn_object);
412 ASSERT3P(db->db_objset, ==, dn->dn_objset);
413 ASSERT3U(db->db_level, <, dn->dn_nlevels);
414 ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
415 db->db_blkid == DMU_SPILL_BLKID ||
416 !avl_is_empty(&dn->dn_dbufs));
417 }
418 if (db->db_blkid == DMU_BONUS_BLKID) {
419 ASSERT(dn != NULL);
420 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
421 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID);
422 } else if (db->db_blkid == DMU_SPILL_BLKID) {
423 ASSERT(dn != NULL);
424 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
425 ASSERT0(db->db.db_offset);
426 } else {
427 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
428 }
429
430 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
431 ASSERT(dr->dr_dbuf == db);
432
433 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
434 ASSERT(dr->dr_dbuf == db);
435
436 /*
437 * We can't assert that db_size matches dn_datablksz because it
438 * can be momentarily different when another thread is doing
439 * dnode_set_blksz().
440 */
441 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
442 dr = db->db_data_pending;
443 /*
444 * It should only be modified in syncing context, so
445 * make sure we only have one copy of the data.
446 */
447 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
448 }
449
450 /* verify db->db_blkptr */
451 if (db->db_blkptr) {
452 if (db->db_parent == dn->dn_dbuf) {
453 /* db is pointed to by the dnode */
454 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
455 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
456 ASSERT(db->db_parent == NULL);
457 else
458 ASSERT(db->db_parent != NULL);
459 if (db->db_blkid != DMU_SPILL_BLKID)
460 ASSERT3P(db->db_blkptr, ==,
461 &dn->dn_phys->dn_blkptr[db->db_blkid]);
462 } else {
463 /* db is pointed to by an indirect block */
464 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT;
465 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
466 ASSERT3U(db->db_parent->db.db_object, ==,
467 db->db.db_object);
468 /*
469 * dnode_grow_indblksz() can make this fail if we don't
470 * have the struct_rwlock. XXX indblksz no longer
471 * grows. safe to do this now?
472 */
473 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
474 ASSERT3P(db->db_blkptr, ==,
475 ((blkptr_t *)db->db_parent->db.db_data +
476 db->db_blkid % epb));
477 }
478 }
479 }
480 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
481 (db->db_buf == NULL || db->db_buf->b_data) &&
482 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID &&
483 db->db_state != DB_FILL && !dn->dn_free_txg) {
484 /*
485 * If the blkptr isn't set but they have nonzero data,
486 * it had better be dirty, otherwise we'll lose that
487 * data when we evict this buffer.
488 */
489 if (db->db_dirtycnt == 0) {
490 uint64_t *buf = db->db.db_data;
491 int i;
492
493 for (i = 0; i < db->db.db_size >> 3; i++) {
494 ASSERT(buf[i] == 0);
495 }
496 }
497 }
498 DB_DNODE_EXIT(db);
499 }
500 #endif
501
502 static void
503 dbuf_clear_data(dmu_buf_impl_t *db)
504 {
505 ASSERT(MUTEX_HELD(&db->db_mtx));
506 dbuf_evict_user(db);
507 db->db_buf = NULL;
508 db->db.db_data = NULL;
509 if (db->db_state != DB_NOFILL)
510 db->db_state = DB_UNCACHED;
511 }
512
513 static void
514 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
515 {
516 ASSERT(MUTEX_HELD(&db->db_mtx));
517 ASSERT(buf != NULL);
518
519 db->db_buf = buf;
520 ASSERT(buf->b_data != NULL);
521 db->db.db_data = buf->b_data;
522 if (!arc_released(buf))
523 arc_set_callback(buf, dbuf_do_evict, db);
524 }
525
526 /*
527 * Loan out an arc_buf for read. Return the loaned arc_buf.
528 */
529 arc_buf_t *
530 dbuf_loan_arcbuf(dmu_buf_impl_t *db)
531 {
532 arc_buf_t *abuf;
533
534 mutex_enter(&db->db_mtx);
535 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
536 int blksz = db->db.db_size;
537 spa_t *spa = db->db_objset->os_spa;
538
539 mutex_exit(&db->db_mtx);
540 abuf = arc_loan_buf(spa, blksz);
541 bcopy(db->db.db_data, abuf->b_data, blksz);
542 } else {
543 abuf = db->db_buf;
544 arc_loan_inuse_buf(abuf, db);
545 dbuf_clear_data(db);
546 mutex_exit(&db->db_mtx);
547 }
548 return (abuf);
549 }
550
551 uint64_t
552 dbuf_whichblock(dnode_t *dn, uint64_t offset)
553 {
554 if (dn->dn_datablkshift) {
555 return (offset >> dn->dn_datablkshift);
556 } else {
557 ASSERT3U(offset, <, dn->dn_datablksz);
558 return (0);
559 }
560 }
561
562 static void
563 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
564 {
565 dmu_buf_impl_t *db = vdb;
566
567 mutex_enter(&db->db_mtx);
568 ASSERT3U(db->db_state, ==, DB_READ);
569 /*
570 * All reads are synchronous, so we must have a hold on the dbuf
571 */
572 ASSERT(refcount_count(&db->db_holds) > 0);
573 ASSERT(db->db_buf == NULL);
574 ASSERT(db->db.db_data == NULL);
575 if (db->db_level == 0 && db->db_freed_in_flight) {
576 /* we were freed in flight; disregard any error */
577 arc_release(buf, db);
578 bzero(buf->b_data, db->db.db_size);
579 arc_buf_freeze(buf);
580 db->db_freed_in_flight = FALSE;
581 dbuf_set_data(db, buf);
582 db->db_state = DB_CACHED;
583 } else if (zio == NULL || zio->io_error == 0) {
584 dbuf_set_data(db, buf);
585 db->db_state = DB_CACHED;
586 } else {
587 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
588 ASSERT3P(db->db_buf, ==, NULL);
589 VERIFY(arc_buf_remove_ref(buf, db));
590 db->db_state = DB_UNCACHED;
591 }
592 cv_broadcast(&db->db_changed);
593 dbuf_rele_and_unlock(db, NULL);
594 }
595
596 static void
597 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
598 {
599 dnode_t *dn;
600 zbookmark_phys_t zb;
601 arc_flags_t aflags = ARC_FLAG_NOWAIT;
602
603 DB_DNODE_ENTER(db);
604 dn = DB_DNODE(db);
605 ASSERT(!refcount_is_zero(&db->db_holds));
606 /* We need the struct_rwlock to prevent db_blkptr from changing. */
607 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
608 ASSERT(MUTEX_HELD(&db->db_mtx));
609 ASSERT(db->db_state == DB_UNCACHED);
610 ASSERT(db->db_buf == NULL);
611
612 if (db->db_blkid == DMU_BONUS_BLKID) {
613 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
614
615 ASSERT3U(bonuslen, <=, db->db.db_size);
616 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
617 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
618 if (bonuslen < DN_MAX_BONUSLEN)
619 bzero(db->db.db_data, DN_MAX_BONUSLEN);
620 if (bonuslen)
621 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
622 DB_DNODE_EXIT(db);
623 db->db_state = DB_CACHED;
624 mutex_exit(&db->db_mtx);
625 return;
626 }
627
628 /*
629 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
630 * processes the delete record and clears the bp while we are waiting
631 * for the dn_mtx (resulting in a "no" from block_freed).
632 */
633 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
634 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
635 BP_IS_HOLE(db->db_blkptr)))) {
636 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
637
638 DB_DNODE_EXIT(db);
639 dbuf_set_data(db, arc_buf_alloc(db->db_objset->os_spa,
640 db->db.db_size, db, type));
641 bzero(db->db.db_data, db->db.db_size);
642 db->db_state = DB_CACHED;
643 *flags |= DB_RF_CACHED;
644 mutex_exit(&db->db_mtx);
645 return;
646 }
647
648 DB_DNODE_EXIT(db);
649
650 db->db_state = DB_READ;
651 mutex_exit(&db->db_mtx);
652
653 if (DBUF_IS_L2CACHEABLE(db))
654 aflags |= ARC_FLAG_L2CACHE;
655 if (DBUF_IS_L2COMPRESSIBLE(db))
656 aflags |= ARC_FLAG_L2COMPRESS;
657
658 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
659 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
660 db->db.db_object, db->db_level, db->db_blkid);
661
662 dbuf_add_ref(db, NULL);
663
664 (void) arc_read(zio, db->db_objset->os_spa, db->db_blkptr,
665 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
666 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
667 &aflags, &zb);
668 if (aflags & ARC_FLAG_CACHED)
669 *flags |= DB_RF_CACHED;
670 }
671
672 int
673 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
674 {
675 int err = 0;
676 boolean_t havepzio = (zio != NULL);
677 boolean_t prefetch;
678 dnode_t *dn;
679
680 /*
681 * We don't have to hold the mutex to check db_state because it
682 * can't be freed while we have a hold on the buffer.
683 */
684 ASSERT(!refcount_is_zero(&db->db_holds));
685
686 if (db->db_state == DB_NOFILL)
687 return (SET_ERROR(EIO));
688
689 DB_DNODE_ENTER(db);
690 dn = DB_DNODE(db);
691 if ((flags & DB_RF_HAVESTRUCT) == 0)
692 rw_enter(&dn->dn_struct_rwlock, RW_READER);
693
694 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
695 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL &&
696 DBUF_IS_CACHEABLE(db);
697
698 mutex_enter(&db->db_mtx);
699 if (db->db_state == DB_CACHED) {
700 mutex_exit(&db->db_mtx);
701 if (prefetch)
702 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
703 db->db.db_size, TRUE);
704 if ((flags & DB_RF_HAVESTRUCT) == 0)
705 rw_exit(&dn->dn_struct_rwlock);
706 DB_DNODE_EXIT(db);
707 } else if (db->db_state == DB_UNCACHED) {
708 spa_t *spa = dn->dn_objset->os_spa;
709
710 if (zio == NULL)
711 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
712 dbuf_read_impl(db, zio, &flags);
713
714 /* dbuf_read_impl has dropped db_mtx for us */
715
716 if (prefetch)
717 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
718 db->db.db_size, flags & DB_RF_CACHED);
719
720 if ((flags & DB_RF_HAVESTRUCT) == 0)
721 rw_exit(&dn->dn_struct_rwlock);
722 DB_DNODE_EXIT(db);
723
724 if (!havepzio)
725 err = zio_wait(zio);
726 } else {
727 /*
728 * Another reader came in while the dbuf was in flight
729 * between UNCACHED and CACHED. Either a writer will finish
730 * writing the buffer (sending the dbuf to CACHED) or the
731 * first reader's request will reach the read_done callback
732 * and send the dbuf to CACHED. Otherwise, a failure
733 * occurred and the dbuf went to UNCACHED.
734 */
735 mutex_exit(&db->db_mtx);
736 if (prefetch)
737 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
738 db->db.db_size, TRUE);
739 if ((flags & DB_RF_HAVESTRUCT) == 0)
740 rw_exit(&dn->dn_struct_rwlock);
741 DB_DNODE_EXIT(db);
742
743 /* Skip the wait per the caller's request. */
744 mutex_enter(&db->db_mtx);
745 if ((flags & DB_RF_NEVERWAIT) == 0) {
746 while (db->db_state == DB_READ ||
747 db->db_state == DB_FILL) {
748 ASSERT(db->db_state == DB_READ ||
749 (flags & DB_RF_HAVESTRUCT) == 0);
750 DTRACE_PROBE2(blocked__read, dmu_buf_impl_t *,
751 db, zio_t *, zio);
752 cv_wait(&db->db_changed, &db->db_mtx);
753 }
754 if (db->db_state == DB_UNCACHED)
755 err = SET_ERROR(EIO);
756 }
757 mutex_exit(&db->db_mtx);
758 }
759
760 ASSERT(err || havepzio || db->db_state == DB_CACHED);
761 return (err);
762 }
763
764 static void
765 dbuf_noread(dmu_buf_impl_t *db)
766 {
767 ASSERT(!refcount_is_zero(&db->db_holds));
768 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
769 mutex_enter(&db->db_mtx);
770 while (db->db_state == DB_READ || db->db_state == DB_FILL)
771 cv_wait(&db->db_changed, &db->db_mtx);
772 if (db->db_state == DB_UNCACHED) {
773 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
774 spa_t *spa = db->db_objset->os_spa;
775
776 ASSERT(db->db_buf == NULL);
777 ASSERT(db->db.db_data == NULL);
778 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type));
779 db->db_state = DB_FILL;
780 } else if (db->db_state == DB_NOFILL) {
781 dbuf_clear_data(db);
782 } else {
783 ASSERT3U(db->db_state, ==, DB_CACHED);
784 }
785 mutex_exit(&db->db_mtx);
786 }
787
788 /*
789 * This is our just-in-time copy function. It makes a copy of
790 * buffers, that have been modified in a previous transaction
791 * group, before we modify them in the current active group.
792 *
793 * This function is used in two places: when we are dirtying a
794 * buffer for the first time in a txg, and when we are freeing
795 * a range in a dnode that includes this buffer.
796 *
797 * Note that when we are called from dbuf_free_range() we do
798 * not put a hold on the buffer, we just traverse the active
799 * dbuf list for the dnode.
800 */
801 static void
802 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
803 {
804 dbuf_dirty_record_t *dr = db->db_last_dirty;
805
806 ASSERT(MUTEX_HELD(&db->db_mtx));
807 ASSERT(db->db.db_data != NULL);
808 ASSERT(db->db_level == 0);
809 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT);
810
811 if (dr == NULL ||
812 (dr->dt.dl.dr_data !=
813 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf)))
814 return;
815
816 /*
817 * If the last dirty record for this dbuf has not yet synced
818 * and its referencing the dbuf data, either:
819 * reset the reference to point to a new copy,
820 * or (if there a no active holders)
821 * just null out the current db_data pointer.
822 */
823 ASSERT(dr->dr_txg >= txg - 2);
824 if (db->db_blkid == DMU_BONUS_BLKID) {
825 /* Note that the data bufs here are zio_bufs */
826 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
827 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
828 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
829 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
830 int size = db->db.db_size;
831 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
832 spa_t *spa = db->db_objset->os_spa;
833
834 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type);
835 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
836 } else {
837 dbuf_clear_data(db);
838 }
839 }
840
841 void
842 dbuf_unoverride(dbuf_dirty_record_t *dr)
843 {
844 dmu_buf_impl_t *db = dr->dr_dbuf;
845 blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
846 uint64_t txg = dr->dr_txg;
847
848 ASSERT(MUTEX_HELD(&db->db_mtx));
849 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
850 ASSERT(db->db_level == 0);
851
852 if (db->db_blkid == DMU_BONUS_BLKID ||
853 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
854 return;
855
856 ASSERT(db->db_data_pending != dr);
857
858 /* free this block */
859 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite)
860 zio_free(db->db_objset->os_spa, txg, bp);
861
862 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
863 dr->dt.dl.dr_nopwrite = B_FALSE;
864
865 /*
866 * Release the already-written buffer, so we leave it in
867 * a consistent dirty state. Note that all callers are
868 * modifying the buffer, so they will immediately do
869 * another (redundant) arc_release(). Therefore, leave
870 * the buf thawed to save the effort of freezing &
871 * immediately re-thawing it.
872 */
873 arc_release(dr->dt.dl.dr_data, db);
874 }
875
876 /*
877 * Evict (if its unreferenced) or clear (if its referenced) any level-0
878 * data blocks in the free range, so that any future readers will find
879 * empty blocks.
880 *
881 * This is a no-op if the dataset is in the middle of an incremental
882 * receive; see comment below for details.
883 */
884 void
885 dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid,
886 dmu_tx_t *tx)
887 {
888 dmu_buf_impl_t db_search;
889 dmu_buf_impl_t *db, *db_next;
890 uint64_t txg = tx->tx_txg;
891 avl_index_t where;
892
893 if (end_blkid > dn->dn_maxblkid && (end_blkid != DMU_SPILL_BLKID))
894 end_blkid = dn->dn_maxblkid;
895 dprintf_dnode(dn, "start=%llu end=%llu\n", start_blkid, end_blkid);
896
897 db_search.db_level = 0;
898 db_search.db_blkid = start_blkid;
899 db_search.db_state = DB_SEARCH;
900
901 mutex_enter(&dn->dn_dbufs_mtx);
902 if (start_blkid >= dn->dn_unlisted_l0_blkid) {
903 /* There can't be any dbufs in this range; no need to search. */
904 #ifdef DEBUG
905 db = avl_find(&dn->dn_dbufs, &db_search, &where);
906 ASSERT3P(db, ==, NULL);
907 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER);
908 ASSERT(db == NULL || db->db_level > 0);
909 #endif
910 mutex_exit(&dn->dn_dbufs_mtx);
911 return;
912 } else if (dmu_objset_is_receiving(dn->dn_objset)) {
913 /*
914 * If we are receiving, we expect there to be no dbufs in
915 * the range to be freed, because receive modifies each
916 * block at most once, and in offset order. If this is
917 * not the case, it can lead to performance problems,
918 * so note that we unexpectedly took the slow path.
919 */
920 atomic_inc_64(&zfs_free_range_recv_miss);
921 }
922
923 db = avl_find(&dn->dn_dbufs, &db_search, &where);
924 ASSERT3P(db, ==, NULL);
925 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER);
926
927 for (; db != NULL; db = db_next) {
928 db_next = AVL_NEXT(&dn->dn_dbufs, db);
929 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
930
931 if (db->db_level != 0 || db->db_blkid > end_blkid) {
932 break;
933 }
934 ASSERT3U(db->db_blkid, >=, start_blkid);
935
936 /* found a level 0 buffer in the range */
937 mutex_enter(&db->db_mtx);
938 if (dbuf_undirty(db, tx)) {
939 /* mutex has been dropped and dbuf destroyed */
940 continue;
941 }
942
943 if (db->db_state == DB_UNCACHED ||
944 db->db_state == DB_NOFILL ||
945 db->db_state == DB_EVICTING) {
946 ASSERT(db->db.db_data == NULL);
947 mutex_exit(&db->db_mtx);
948 continue;
949 }
950 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
951 /* will be handled in dbuf_read_done or dbuf_rele */
952 db->db_freed_in_flight = TRUE;
953 mutex_exit(&db->db_mtx);
954 continue;
955 }
956 if (refcount_count(&db->db_holds) == 0) {
957 ASSERT(db->db_buf);
958 dbuf_clear(db);
959 continue;
960 }
961 /* The dbuf is referenced */
962
963 if (db->db_last_dirty != NULL) {
964 dbuf_dirty_record_t *dr = db->db_last_dirty;
965
966 if (dr->dr_txg == txg) {
967 /*
968 * This buffer is "in-use", re-adjust the file
969 * size to reflect that this buffer may
970 * contain new data when we sync.
971 */
972 if (db->db_blkid != DMU_SPILL_BLKID &&
973 db->db_blkid > dn->dn_maxblkid)
974 dn->dn_maxblkid = db->db_blkid;
975 dbuf_unoverride(dr);
976 } else {
977 /*
978 * This dbuf is not dirty in the open context.
979 * Either uncache it (if its not referenced in
980 * the open context) or reset its contents to
981 * empty.
982 */
983 dbuf_fix_old_data(db, txg);
984 }
985 }
986 /* clear the contents if its cached */
987 if (db->db_state == DB_CACHED) {
988 ASSERT(db->db.db_data != NULL);
989 arc_release(db->db_buf, db);
990 bzero(db->db.db_data, db->db.db_size);
991 arc_buf_freeze(db->db_buf);
992 }
993
994 mutex_exit(&db->db_mtx);
995 }
996 mutex_exit(&dn->dn_dbufs_mtx);
997 }
998
999 static int
1000 dbuf_block_freeable(dmu_buf_impl_t *db)
1001 {
1002 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
1003 uint64_t birth_txg = 0;
1004
1005 /*
1006 * We don't need any locking to protect db_blkptr:
1007 * If it's syncing, then db_last_dirty will be set
1008 * so we'll ignore db_blkptr.
1009 *
1010 * This logic ensures that only block births for
1011 * filled blocks are considered.
1012 */
1013 ASSERT(MUTEX_HELD(&db->db_mtx));
1014 if (db->db_last_dirty && (db->db_blkptr == NULL ||
1015 !BP_IS_HOLE(db->db_blkptr))) {
1016 birth_txg = db->db_last_dirty->dr_txg;
1017 } else if (db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr)) {
1018 birth_txg = db->db_blkptr->blk_birth;
1019 }
1020
1021 /*
1022 * If this block don't exist or is in a snapshot, it can't be freed.
1023 * Don't pass the bp to dsl_dataset_block_freeable() since we
1024 * are holding the db_mtx lock and might deadlock if we are
1025 * prefetching a dedup-ed block.
1026 */
1027 if (birth_txg != 0)
1028 return (ds == NULL ||
1029 dsl_dataset_block_freeable(ds, NULL, birth_txg));
1030 else
1031 return (B_FALSE);
1032 }
1033
1034 void
1035 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
1036 {
1037 arc_buf_t *buf, *obuf;
1038 int osize = db->db.db_size;
1039 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
1040 dnode_t *dn;
1041
1042 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1043
1044 DB_DNODE_ENTER(db);
1045 dn = DB_DNODE(db);
1046
1047 /* XXX does *this* func really need the lock? */
1048 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
1049
1050 /*
1051 * This call to dmu_buf_will_dirty() with the dn_struct_rwlock held
1052 * is OK, because there can be no other references to the db
1053 * when we are changing its size, so no concurrent DB_FILL can
1054 * be happening.
1055 */
1056 /*
1057 * XXX we should be doing a dbuf_read, checking the return
1058 * value and returning that up to our callers
1059 */
1060 dmu_buf_will_dirty(&db->db, tx);
1061
1062 /* create the data buffer for the new block */
1063 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type);
1064
1065 /* copy old block data to the new block */
1066 obuf = db->db_buf;
1067 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
1068 /* zero the remainder */
1069 if (size > osize)
1070 bzero((uint8_t *)buf->b_data + osize, size - osize);
1071
1072 mutex_enter(&db->db_mtx);
1073 dbuf_set_data(db, buf);
1074 VERIFY(arc_buf_remove_ref(obuf, db));
1075 db->db.db_size = size;
1076
1077 if (db->db_level == 0) {
1078 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
1079 db->db_last_dirty->dt.dl.dr_data = buf;
1080 }
1081 mutex_exit(&db->db_mtx);
1082
1083 dnode_willuse_space(dn, size-osize, tx);
1084 DB_DNODE_EXIT(db);
1085 }
1086
1087 void
1088 dbuf_release_bp(dmu_buf_impl_t *db)
1089 {
1090 objset_t *os = db->db_objset;
1091
1092 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
1093 ASSERT(arc_released(os->os_phys_buf) ||
1094 list_link_active(&os->os_dsl_dataset->ds_synced_link));
1095 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf));
1096
1097 (void) arc_release(db->db_buf, db);
1098 }
1099
1100 dbuf_dirty_record_t *
1101 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1102 {
1103 dnode_t *dn;
1104 objset_t *os;
1105 dbuf_dirty_record_t **drp, *dr;
1106 int drop_struct_lock = FALSE;
1107 boolean_t do_free_accounting = B_FALSE;
1108 int txgoff = tx->tx_txg & TXG_MASK;
1109
1110 ASSERT(tx->tx_txg != 0);
1111 ASSERT(!refcount_is_zero(&db->db_holds));
1112 DMU_TX_DIRTY_BUF(tx, db);
1113
1114 DB_DNODE_ENTER(db);
1115 dn = DB_DNODE(db);
1116 /*
1117 * Shouldn't dirty a regular buffer in syncing context. Private
1118 * objects may be dirtied in syncing context, but only if they
1119 * were already pre-dirtied in open context.
1120 */
1121 ASSERT(!dmu_tx_is_syncing(tx) ||
1122 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
1123 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1124 dn->dn_objset->os_dsl_dataset == NULL);
1125 /*
1126 * We make this assert for private objects as well, but after we
1127 * check if we're already dirty. They are allowed to re-dirty
1128 * in syncing context.
1129 */
1130 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1131 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1132 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1133
1134 mutex_enter(&db->db_mtx);
1135 /*
1136 * XXX make this true for indirects too? The problem is that
1137 * transactions created with dmu_tx_create_assigned() from
1138 * syncing context don't bother holding ahead.
1139 */
1140 ASSERT(db->db_level != 0 ||
1141 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
1142 db->db_state == DB_NOFILL);
1143
1144 mutex_enter(&dn->dn_mtx);
1145 /*
1146 * Don't set dirtyctx to SYNC if we're just modifying this as we
1147 * initialize the objset.
1148 */
1149 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
1150 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
1151 dn->dn_dirtyctx =
1152 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
1153 ASSERT(dn->dn_dirtyctx_firstset == NULL);
1154 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
1155 }
1156 mutex_exit(&dn->dn_mtx);
1157
1158 if (db->db_blkid == DMU_SPILL_BLKID)
1159 dn->dn_have_spill = B_TRUE;
1160
1161 /*
1162 * If this buffer is already dirty, we're done.
1163 */
1164 drp = &db->db_last_dirty;
1165 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
1166 db->db.db_object == DMU_META_DNODE_OBJECT);
1167 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
1168 drp = &dr->dr_next;
1169 if (dr && dr->dr_txg == tx->tx_txg) {
1170 DB_DNODE_EXIT(db);
1171
1172 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
1173 /*
1174 * If this buffer has already been written out,
1175 * we now need to reset its state.
1176 */
1177 dbuf_unoverride(dr);
1178 if (db->db.db_object != DMU_META_DNODE_OBJECT &&
1179 db->db_state != DB_NOFILL)
1180 arc_buf_thaw(db->db_buf);
1181 }
1182 mutex_exit(&db->db_mtx);
1183 return (dr);
1184 }
1185
1186 /*
1187 * Only valid if not already dirty.
1188 */
1189 ASSERT(dn->dn_object == 0 ||
1190 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1191 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1192
1193 ASSERT3U(dn->dn_nlevels, >, db->db_level);
1194 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
1195 dn->dn_phys->dn_nlevels > db->db_level ||
1196 dn->dn_next_nlevels[txgoff] > db->db_level ||
1197 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
1198 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
1199
1200 /*
1201 * We should only be dirtying in syncing context if it's the
1202 * mos or we're initializing the os or it's a special object.
1203 * However, we are allowed to dirty in syncing context provided
1204 * we already dirtied it in open context. Hence we must make
1205 * this assertion only if we're not already dirty.
1206 */
1207 os = dn->dn_objset;
1208 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1209 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
1210 ASSERT(db->db.db_size != 0);
1211
1212 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1213
1214 if (db->db_blkid != DMU_BONUS_BLKID) {
1215 /*
1216 * Update the accounting.
1217 * Note: we delay "free accounting" until after we drop
1218 * the db_mtx. This keeps us from grabbing other locks
1219 * (and possibly deadlocking) in bp_get_dsize() while
1220 * also holding the db_mtx.
1221 */
1222 dnode_willuse_space(dn, db->db.db_size, tx);
1223 do_free_accounting = dbuf_block_freeable(db);
1224 }
1225
1226 /*
1227 * If this buffer is dirty in an old transaction group we need
1228 * to make a copy of it so that the changes we make in this
1229 * transaction group won't leak out when we sync the older txg.
1230 */
1231 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP);
1232 if (db->db_level == 0) {
1233 void *data_old = db->db_buf;
1234
1235 if (db->db_state != DB_NOFILL) {
1236 if (db->db_blkid == DMU_BONUS_BLKID) {
1237 dbuf_fix_old_data(db, tx->tx_txg);
1238 data_old = db->db.db_data;
1239 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1240 /*
1241 * Release the data buffer from the cache so
1242 * that we can modify it without impacting
1243 * possible other users of this cached data
1244 * block. Note that indirect blocks and
1245 * private objects are not released until the
1246 * syncing state (since they are only modified
1247 * then).
1248 */
1249 arc_release(db->db_buf, db);
1250 dbuf_fix_old_data(db, tx->tx_txg);
1251 data_old = db->db_buf;
1252 }
1253 ASSERT(data_old != NULL);
1254 }
1255 dr->dt.dl.dr_data = data_old;
1256 } else {
1257 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1258 list_create(&dr->dt.di.dr_children,
1259 sizeof (dbuf_dirty_record_t),
1260 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1261 }
1262 if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL)
1263 dr->dr_accounted = db->db.db_size;
1264 dr->dr_dbuf = db;
1265 dr->dr_txg = tx->tx_txg;
1266 dr->dr_next = *drp;
1267 *drp = dr;
1268
1269 /*
1270 * We could have been freed_in_flight between the dbuf_noread
1271 * and dbuf_dirty. We win, as though the dbuf_noread() had
1272 * happened after the free.
1273 */
1274 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1275 db->db_blkid != DMU_SPILL_BLKID) {
1276 mutex_enter(&dn->dn_mtx);
1277 if (dn->dn_free_ranges[txgoff] != NULL) {
1278 range_tree_clear(dn->dn_free_ranges[txgoff],
1279 db->db_blkid, 1);
1280 }
1281 mutex_exit(&dn->dn_mtx);
1282 db->db_freed_in_flight = FALSE;
1283 }
1284
1285 /*
1286 * This buffer is now part of this txg
1287 */
1288 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1289 db->db_dirtycnt += 1;
1290 ASSERT3U(db->db_dirtycnt, <=, 3);
1291
1292 mutex_exit(&db->db_mtx);
1293
1294 if (db->db_blkid == DMU_BONUS_BLKID ||
1295 db->db_blkid == DMU_SPILL_BLKID) {
1296 mutex_enter(&dn->dn_mtx);
1297 ASSERT(!list_link_active(&dr->dr_dirty_node));
1298 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1299 mutex_exit(&dn->dn_mtx);
1300 dnode_setdirty(dn, tx);
1301 DB_DNODE_EXIT(db);
1302 return (dr);
1303 }
1304
1305 /*
1306 * The dn_struct_rwlock prevents db_blkptr from changing
1307 * due to a write from syncing context completing
1308 * while we are running, so we want to acquire it before
1309 * looking at db_blkptr.
1310 */
1311 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1312 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1313 drop_struct_lock = TRUE;
1314 }
1315
1316 if (do_free_accounting) {
1317 blkptr_t *bp = db->db_blkptr;
1318 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1319 bp_get_dsize(os->os_spa, bp) : db->db.db_size;
1320 /*
1321 * This is only a guess -- if the dbuf is dirty
1322 * in a previous txg, we don't know how much
1323 * space it will use on disk yet. We should
1324 * really have the struct_rwlock to access
1325 * db_blkptr, but since this is just a guess,
1326 * it's OK if we get an odd answer.
1327 */
1328 ddt_prefetch(os->os_spa, bp);
1329 dnode_willuse_space(dn, -willfree, tx);
1330 }
1331
1332 if (db->db_level == 0) {
1333 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1334 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1335 }
1336
1337 if (db->db_level+1 < dn->dn_nlevels) {
1338 dmu_buf_impl_t *parent = db->db_parent;
1339 dbuf_dirty_record_t *di;
1340 int parent_held = FALSE;
1341
1342 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1343 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1344
1345 parent = dbuf_hold_level(dn, db->db_level+1,
1346 db->db_blkid >> epbs, FTAG);
1347 ASSERT(parent != NULL);
1348 parent_held = TRUE;
1349 }
1350 if (drop_struct_lock)
1351 rw_exit(&dn->dn_struct_rwlock);
1352 ASSERT3U(db->db_level+1, ==, parent->db_level);
1353 di = dbuf_dirty(parent, tx);
1354 if (parent_held)
1355 dbuf_rele(parent, FTAG);
1356
1357 mutex_enter(&db->db_mtx);
1358 /*
1359 * Since we've dropped the mutex, it's possible that
1360 * dbuf_undirty() might have changed this out from under us.
1361 */
1362 if (db->db_last_dirty == dr ||
1363 dn->dn_object == DMU_META_DNODE_OBJECT) {
1364 mutex_enter(&di->dt.di.dr_mtx);
1365 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1366 ASSERT(!list_link_active(&dr->dr_dirty_node));
1367 list_insert_tail(&di->dt.di.dr_children, dr);
1368 mutex_exit(&di->dt.di.dr_mtx);
1369 dr->dr_parent = di;
1370 }
1371 mutex_exit(&db->db_mtx);
1372 } else {
1373 ASSERT(db->db_level+1 == dn->dn_nlevels);
1374 ASSERT(db->db_blkid < dn->dn_nblkptr);
1375 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf);
1376 mutex_enter(&dn->dn_mtx);
1377 ASSERT(!list_link_active(&dr->dr_dirty_node));
1378 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1379 mutex_exit(&dn->dn_mtx);
1380 if (drop_struct_lock)
1381 rw_exit(&dn->dn_struct_rwlock);
1382 }
1383
1384 dnode_setdirty(dn, tx);
1385 DB_DNODE_EXIT(db);
1386 return (dr);
1387 }
1388
1389 /*
1390 * Undirty a buffer in the transaction group referenced by the given
1391 * transaction. Return whether this evicted the dbuf.
1392 */
1393 static boolean_t
1394 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1395 {
1396 dnode_t *dn;
1397 uint64_t txg = tx->tx_txg;
1398 dbuf_dirty_record_t *dr, **drp;
1399
1400 ASSERT(txg != 0);
1401 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1402 ASSERT0(db->db_level);
1403 ASSERT(MUTEX_HELD(&db->db_mtx));
1404
1405 /*
1406 * If this buffer is not dirty, we're done.
1407 */
1408 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1409 if (dr->dr_txg <= txg)
1410 break;
1411 if (dr == NULL || dr->dr_txg < txg)
1412 return (B_FALSE);
1413 ASSERT(dr->dr_txg == txg);
1414 ASSERT(dr->dr_dbuf == db);
1415
1416 DB_DNODE_ENTER(db);
1417 dn = DB_DNODE(db);
1418
1419 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1420
1421 ASSERT(db->db.db_size != 0);
1422
1423 /*
1424 * Any space we accounted for in dp_dirty_* will be cleaned up by
1425 * dsl_pool_sync(). This is relatively rare so the discrepancy
1426 * is not a big deal.
1427 */
1428
1429 *drp = dr->dr_next;
1430
1431 /*
1432 * Note that there are three places in dbuf_dirty()
1433 * where this dirty record may be put on a list.
1434 * Make sure to do a list_remove corresponding to
1435 * every one of those list_insert calls.
1436 */
1437 if (dr->dr_parent) {
1438 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1439 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1440 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1441 } else if (db->db_blkid == DMU_SPILL_BLKID ||
1442 db->db_level+1 == dn->dn_nlevels) {
1443 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
1444 mutex_enter(&dn->dn_mtx);
1445 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
1446 mutex_exit(&dn->dn_mtx);
1447 }
1448 DB_DNODE_EXIT(db);
1449
1450 if (db->db_state != DB_NOFILL) {
1451 dbuf_unoverride(dr);
1452
1453 ASSERT(db->db_buf != NULL);
1454 ASSERT(dr->dt.dl.dr_data != NULL);
1455 if (dr->dt.dl.dr_data != db->db_buf)
1456 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db));
1457 }
1458
1459 if (db->db_level != 0) {
1460 mutex_destroy(&dr->dt.di.dr_mtx);
1461 list_destroy(&dr->dt.di.dr_children);
1462 }
1463
1464 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1465
1466 ASSERT(db->db_dirtycnt > 0);
1467 db->db_dirtycnt -= 1;
1468
1469 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1470 arc_buf_t *buf = db->db_buf;
1471
1472 ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
1473 dbuf_clear_data(db);
1474 VERIFY(arc_buf_remove_ref(buf, db));
1475 dbuf_evict(db);
1476 return (B_TRUE);
1477 }
1478
1479 return (B_FALSE);
1480 }
1481
1482 void
1483 dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx)
1484 {
1485 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1486 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1487
1488 ASSERT(tx->tx_txg != 0);
1489 ASSERT(!refcount_is_zero(&db->db_holds));
1490
1491 DB_DNODE_ENTER(db);
1492 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
1493 rf |= DB_RF_HAVESTRUCT;
1494 DB_DNODE_EXIT(db);
1495 (void) dbuf_read(db, NULL, rf);
1496 (void) dbuf_dirty(db, tx);
1497 }
1498
1499 void
1500 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1501 {
1502 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1503
1504 db->db_state = DB_NOFILL;
1505
1506 dmu_buf_will_fill(db_fake, tx);
1507 }
1508
1509 void
1510 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1511 {
1512 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1513
1514 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1515 ASSERT(tx->tx_txg != 0);
1516 ASSERT(db->db_level == 0);
1517 ASSERT(!refcount_is_zero(&db->db_holds));
1518
1519 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1520 dmu_tx_private_ok(tx));
1521
1522 dbuf_noread(db);
1523 (void) dbuf_dirty(db, tx);
1524 }
1525
1526 #pragma weak dmu_buf_fill_done = dbuf_fill_done
1527 /* ARGSUSED */
1528 void
1529 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1530 {
1531 mutex_enter(&db->db_mtx);
1532 DBUF_VERIFY(db);
1533
1534 if (db->db_state == DB_FILL) {
1535 if (db->db_level == 0 && db->db_freed_in_flight) {
1536 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1537 /* we were freed while filling */
1538 /* XXX dbuf_undirty? */
1539 bzero(db->db.db_data, db->db.db_size);
1540 db->db_freed_in_flight = FALSE;
1541 }
1542 db->db_state = DB_CACHED;
1543 cv_broadcast(&db->db_changed);
1544 }
1545 mutex_exit(&db->db_mtx);
1546 }
1547
1548 void
1549 dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data,
1550 bp_embedded_type_t etype, enum zio_compress comp,
1551 int uncompressed_size, int compressed_size, int byteorder,
1552 dmu_tx_t *tx)
1553 {
1554 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
1555 struct dirty_leaf *dl;
1556 dmu_object_type_t type;
1557
1558 DB_DNODE_ENTER(db);
1559 type = DB_DNODE(db)->dn_type;
1560 DB_DNODE_EXIT(db);
1561
1562 ASSERT0(db->db_level);
1563 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1564
1565 dmu_buf_will_not_fill(dbuf, tx);
1566
1567 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
1568 dl = &db->db_last_dirty->dt.dl;
1569 encode_embedded_bp_compressed(&dl->dr_overridden_by,
1570 data, comp, uncompressed_size, compressed_size);
1571 BPE_SET_ETYPE(&dl->dr_overridden_by, etype);
1572 BP_SET_TYPE(&dl->dr_overridden_by, type);
1573 BP_SET_LEVEL(&dl->dr_overridden_by, 0);
1574 BP_SET_BYTEORDER(&dl->dr_overridden_by, byteorder);
1575
1576 dl->dr_override_state = DR_OVERRIDDEN;
1577 dl->dr_overridden_by.blk_birth = db->db_last_dirty->dr_txg;
1578 }
1579
1580 /*
1581 * Directly assign a provided arc buf to a given dbuf if it's not referenced
1582 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
1583 */
1584 void
1585 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
1586 {
1587 ASSERT(!refcount_is_zero(&db->db_holds));
1588 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1589 ASSERT(db->db_level == 0);
1590 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
1591 ASSERT(buf != NULL);
1592 ASSERT(arc_buf_size(buf) == db->db.db_size);
1593 ASSERT(tx->tx_txg != 0);
1594
1595 arc_return_buf(buf, db);
1596 ASSERT(arc_released(buf));
1597
1598 mutex_enter(&db->db_mtx);
1599
1600 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1601 cv_wait(&db->db_changed, &db->db_mtx);
1602
1603 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
1604
1605 if (db->db_state == DB_CACHED &&
1606 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
1607 mutex_exit(&db->db_mtx);
1608 (void) dbuf_dirty(db, tx);
1609 bcopy(buf->b_data, db->db.db_data, db->db.db_size);
1610 VERIFY(arc_buf_remove_ref(buf, db));
1611 xuio_stat_wbuf_copied();
1612 return;
1613 }
1614
1615 xuio_stat_wbuf_nocopy();
1616 if (db->db_state == DB_CACHED) {
1617 dbuf_dirty_record_t *dr = db->db_last_dirty;
1618
1619 ASSERT(db->db_buf != NULL);
1620 if (dr != NULL && dr->dr_txg == tx->tx_txg) {
1621 ASSERT(dr->dt.dl.dr_data == db->db_buf);
1622 if (!arc_released(db->db_buf)) {
1623 ASSERT(dr->dt.dl.dr_override_state ==
1624 DR_OVERRIDDEN);
1625 arc_release(db->db_buf, db);
1626 }
1627 dr->dt.dl.dr_data = buf;
1628 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1629 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
1630 arc_release(db->db_buf, db);
1631 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1632 }
1633 db->db_buf = NULL;
1634 }
1635 ASSERT(db->db_buf == NULL);
1636 dbuf_set_data(db, buf);
1637 db->db_state = DB_FILL;
1638 mutex_exit(&db->db_mtx);
1639 (void) dbuf_dirty(db, tx);
1640 dmu_buf_fill_done(&db->db, tx);
1641 }
1642
1643 /*
1644 * "Clear" the contents of this dbuf. This will mark the dbuf
1645 * EVICTING and clear *most* of its references. Unfortunately,
1646 * when we are not holding the dn_dbufs_mtx, we can't clear the
1647 * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
1648 * in this case. For callers from the DMU we will usually see:
1649 * dbuf_clear()->arc_clear_callback()->dbuf_do_evict()->dbuf_destroy()
1650 * For the arc callback, we will usually see:
1651 * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
1652 * Sometimes, though, we will get a mix of these two:
1653 * DMU: dbuf_clear()->arc_clear_callback()
1654 * ARC: dbuf_do_evict()->dbuf_destroy()
1655 *
1656 * This routine will dissociate the dbuf from the arc, by calling
1657 * arc_clear_callback(), but will not evict the data from the ARC.
1658 */
1659 void
1660 dbuf_clear(dmu_buf_impl_t *db)
1661 {
1662 dnode_t *dn;
1663 dmu_buf_impl_t *parent = db->db_parent;
1664 dmu_buf_impl_t *dndb;
1665 boolean_t dbuf_gone = B_FALSE;
1666
1667 ASSERT(MUTEX_HELD(&db->db_mtx));
1668 ASSERT(refcount_is_zero(&db->db_holds));
1669
1670 dbuf_evict_user(db);
1671
1672 if (db->db_state == DB_CACHED) {
1673 ASSERT(db->db.db_data != NULL);
1674 if (db->db_blkid == DMU_BONUS_BLKID) {
1675 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1676 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1677 }
1678 db->db.db_data = NULL;
1679 db->db_state = DB_UNCACHED;
1680 }
1681
1682 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
1683 ASSERT(db->db_data_pending == NULL);
1684
1685 db->db_state = DB_EVICTING;
1686 db->db_blkptr = NULL;
1687
1688 DB_DNODE_ENTER(db);
1689 dn = DB_DNODE(db);
1690 dndb = dn->dn_dbuf;
1691 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1692 avl_remove(&dn->dn_dbufs, db);
1693 atomic_dec_32(&dn->dn_dbufs_count);
1694 membar_producer();
1695 DB_DNODE_EXIT(db);
1696 /*
1697 * Decrementing the dbuf count means that the hold corresponding
1698 * to the removed dbuf is no longer discounted in dnode_move(),
1699 * so the dnode cannot be moved until after we release the hold.
1700 * The membar_producer() ensures visibility of the decremented
1701 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually
1702 * release any lock.
1703 */
1704 dnode_rele(dn, db);
1705 db->db_dnode_handle = NULL;
1706 } else {
1707 DB_DNODE_EXIT(db);
1708 }
1709
1710 if (db->db_buf)
1711 dbuf_gone = arc_clear_callback(db->db_buf);
1712
1713 if (!dbuf_gone)
1714 mutex_exit(&db->db_mtx);
1715
1716 /*
1717 * If this dbuf is referenced from an indirect dbuf,
1718 * decrement the ref count on the indirect dbuf.
1719 */
1720 if (parent && parent != dndb)
1721 dbuf_rele(parent, db);
1722 }
1723
1724 static int
1725 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1726 dmu_buf_impl_t **parentp, blkptr_t **bpp)
1727 {
1728 int nlevels, epbs;
1729
1730 *parentp = NULL;
1731 *bpp = NULL;
1732
1733 ASSERT(blkid != DMU_BONUS_BLKID);
1734
1735 if (blkid == DMU_SPILL_BLKID) {
1736 mutex_enter(&dn->dn_mtx);
1737 if (dn->dn_have_spill &&
1738 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
1739 *bpp = &dn->dn_phys->dn_spill;
1740 else
1741 *bpp = NULL;
1742 dbuf_add_ref(dn->dn_dbuf, NULL);
1743 *parentp = dn->dn_dbuf;
1744 mutex_exit(&dn->dn_mtx);
1745 return (0);
1746 }
1747
1748 if (dn->dn_phys->dn_nlevels == 0)
1749 nlevels = 1;
1750 else
1751 nlevels = dn->dn_phys->dn_nlevels;
1752
1753 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1754
1755 ASSERT3U(level * epbs, <, 64);
1756 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1757 if (level >= nlevels ||
1758 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
1759 /* the buffer has no parent yet */
1760 return (SET_ERROR(ENOENT));
1761 } else if (level < nlevels-1) {
1762 /* this block is referenced from an indirect block */
1763 int err = dbuf_hold_impl(dn, level+1,
1764 blkid >> epbs, fail_sparse, NULL, parentp);
1765 if (err)
1766 return (err);
1767 err = dbuf_read(*parentp, NULL,
1768 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1769 if (err) {
1770 dbuf_rele(*parentp, NULL);
1771 *parentp = NULL;
1772 return (err);
1773 }
1774 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1775 (blkid & ((1ULL << epbs) - 1));
1776 return (0);
1777 } else {
1778 /* the block is referenced from the dnode */
1779 ASSERT3U(level, ==, nlevels-1);
1780 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1781 blkid < dn->dn_phys->dn_nblkptr);
1782 if (dn->dn_dbuf) {
1783 dbuf_add_ref(dn->dn_dbuf, NULL);
1784 *parentp = dn->dn_dbuf;
1785 }
1786 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1787 return (0);
1788 }
1789 }
1790
1791 static dmu_buf_impl_t *
1792 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1793 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1794 {
1795 objset_t *os = dn->dn_objset;
1796 dmu_buf_impl_t *db, *odb;
1797
1798 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1799 ASSERT(dn->dn_type != DMU_OT_NONE);
1800
1801 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP);
1802
1803 db->db_objset = os;
1804 db->db.db_object = dn->dn_object;
1805 db->db_level = level;
1806 db->db_blkid = blkid;
1807 db->db_last_dirty = NULL;
1808 db->db_dirtycnt = 0;
1809 db->db_dnode_handle = dn->dn_handle;
1810 db->db_parent = parent;
1811 db->db_blkptr = blkptr;
1812
1813 db->db_user = NULL;
1814 db->db_immediate_evict = 0;
1815 db->db_freed_in_flight = 0;
1816
1817 if (blkid == DMU_BONUS_BLKID) {
1818 ASSERT3P(parent, ==, dn->dn_dbuf);
1819 db->db.db_size = DN_MAX_BONUSLEN -
1820 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1821 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1822 db->db.db_offset = DMU_BONUS_BLKID;
1823 db->db_state = DB_UNCACHED;
1824 /* the bonus dbuf is not placed in the hash table */
1825 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1826 return (db);
1827 } else if (blkid == DMU_SPILL_BLKID) {
1828 db->db.db_size = (blkptr != NULL) ?
1829 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE;
1830 db->db.db_offset = 0;
1831 } else {
1832 int blocksize =
1833 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz;
1834 db->db.db_size = blocksize;
1835 db->db.db_offset = db->db_blkid * blocksize;
1836 }
1837
1838 /*
1839 * Hold the dn_dbufs_mtx while we get the new dbuf
1840 * in the hash table *and* added to the dbufs list.
1841 * This prevents a possible deadlock with someone
1842 * trying to look up this dbuf before its added to the
1843 * dn_dbufs list.
1844 */
1845 mutex_enter(&dn->dn_dbufs_mtx);
1846 db->db_state = DB_EVICTING;
1847 if ((odb = dbuf_hash_insert(db)) != NULL) {
1848 /* someone else inserted it first */
1849 kmem_cache_free(dbuf_cache, db);
1850 mutex_exit(&dn->dn_dbufs_mtx);
1851 return (odb);
1852 }
1853 avl_add(&dn->dn_dbufs, db);
1854 if (db->db_level == 0 && db->db_blkid >=
1855 dn->dn_unlisted_l0_blkid)
1856 dn->dn_unlisted_l0_blkid = db->db_blkid + 1;
1857 db->db_state = DB_UNCACHED;
1858 mutex_exit(&dn->dn_dbufs_mtx);
1859 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1860
1861 if (parent && parent != dn->dn_dbuf)
1862 dbuf_add_ref(parent, db);
1863
1864 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1865 refcount_count(&dn->dn_holds) > 0);
1866 (void) refcount_add(&dn->dn_holds, db);
1867 atomic_inc_32(&dn->dn_dbufs_count);
1868
1869 dprintf_dbuf(db, "db=%p\n", db);
1870
1871 return (db);
1872 }
1873
1874 static int
1875 dbuf_do_evict(void *private)
1876 {
1877 dmu_buf_impl_t *db = private;
1878
1879 if (!MUTEX_HELD(&db->db_mtx))
1880 mutex_enter(&db->db_mtx);
1881
1882 ASSERT(refcount_is_zero(&db->db_holds));
1883
1884 if (db->db_state != DB_EVICTING) {
1885 ASSERT(db->db_state == DB_CACHED);
1886 DBUF_VERIFY(db);
1887 db->db_buf = NULL;
1888 dbuf_evict(db);
1889 } else {
1890 mutex_exit(&db->db_mtx);
1891 dbuf_destroy(db);
1892 }
1893 return (0);
1894 }
1895
1896 static void
1897 dbuf_destroy(dmu_buf_impl_t *db)
1898 {
1899 ASSERT(refcount_is_zero(&db->db_holds));
1900
1901 if (db->db_blkid != DMU_BONUS_BLKID) {
1902 /*
1903 * If this dbuf is still on the dn_dbufs list,
1904 * remove it from that list.
1905 */
1906 if (db->db_dnode_handle != NULL) {
1907 dnode_t *dn;
1908
1909 DB_DNODE_ENTER(db);
1910 dn = DB_DNODE(db);
1911 mutex_enter(&dn->dn_dbufs_mtx);
1912 avl_remove(&dn->dn_dbufs, db);
1913 atomic_dec_32(&dn->dn_dbufs_count);
1914 mutex_exit(&dn->dn_dbufs_mtx);
1915 DB_DNODE_EXIT(db);
1916 /*
1917 * Decrementing the dbuf count means that the hold
1918 * corresponding to the removed dbuf is no longer
1919 * discounted in dnode_move(), so the dnode cannot be
1920 * moved until after we release the hold.
1921 */
1922 dnode_rele(dn, db);
1923 db->db_dnode_handle = NULL;
1924 }
1925 dbuf_hash_remove(db);
1926 }
1927 db->db_parent = NULL;
1928 db->db_buf = NULL;
1929
1930 ASSERT(db->db.db_data == NULL);
1931 ASSERT(db->db_hash_next == NULL);
1932 ASSERT(db->db_blkptr == NULL);
1933 ASSERT(db->db_data_pending == NULL);
1934
1935 kmem_cache_free(dbuf_cache, db);
1936 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1937 }
1938
1939 void
1940 dbuf_prefetch(dnode_t *dn, uint64_t blkid, zio_priority_t prio)
1941 {
1942 dmu_buf_impl_t *db = NULL;
1943 blkptr_t *bp = NULL;
1944
1945 ASSERT(blkid != DMU_BONUS_BLKID);
1946 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1947
1948 if (dnode_block_freed(dn, blkid))
1949 return;
1950
1951 /* dbuf_find() returns with db_mtx held */
1952 if (db = dbuf_find(dn->dn_objset, dn->dn_object, 0, blkid)) {
1953 /*
1954 * This dbuf is already in the cache. We assume that
1955 * it is already CACHED, or else about to be either
1956 * read or filled.
1957 */
1958 mutex_exit(&db->db_mtx);
1959 return;
1960 }
1961
1962 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) {
1963 if (bp && !BP_IS_HOLE(bp) && !BP_IS_EMBEDDED(bp)) {
1964 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
1965 arc_flags_t aflags =
1966 ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
1967 zbookmark_phys_t zb;
1968
1969 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1970 dn->dn_object, 0, blkid);
1971
1972 (void) arc_read(NULL, dn->dn_objset->os_spa,
1973 bp, NULL, NULL, prio,
1974 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1975 &aflags, &zb);
1976 }
1977 if (db)
1978 dbuf_rele(db, NULL);
1979 }
1980 }
1981
1982 /*
1983 * Returns with db_holds incremented, and db_mtx not held.
1984 * Note: dn_struct_rwlock must be held.
1985 */
1986 int
1987 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
1988 void *tag, dmu_buf_impl_t **dbp)
1989 {
1990 dmu_buf_impl_t *db, *parent = NULL;
1991
1992 ASSERT(blkid != DMU_BONUS_BLKID);
1993 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1994 ASSERT3U(dn->dn_nlevels, >, level);
1995
1996 *dbp = NULL;
1997 top:
1998 /* dbuf_find() returns with db_mtx held */
1999 db = dbuf_find(dn->dn_objset, dn->dn_object, level, blkid);
2000
2001 if (db == NULL) {
2002 blkptr_t *bp = NULL;
2003 int err;
2004
2005 ASSERT3P(parent, ==, NULL);
2006 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp);
2007 if (fail_sparse) {
2008 if (err == 0 && bp && BP_IS_HOLE(bp))
2009 err = SET_ERROR(ENOENT);
2010 if (err) {
2011 if (parent)
2012 dbuf_rele(parent, NULL);
2013 return (err);
2014 }
2015 }
2016 if (err && err != ENOENT)
2017 return (err);
2018 db = dbuf_create(dn, level, blkid, parent, bp);
2019 }
2020
2021 if (db->db_buf && refcount_is_zero(&db->db_holds)) {
2022 arc_buf_add_ref(db->db_buf, db);
2023 if (db->db_buf->b_data == NULL) {
2024 dbuf_clear(db);
2025 if (parent) {
2026 dbuf_rele(parent, NULL);
2027 parent = NULL;
2028 }
2029 goto top;
2030 }
2031 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data);
2032 }
2033
2034 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf));
2035
2036 /*
2037 * If this buffer is currently syncing out, and we are are
2038 * still referencing it from db_data, we need to make a copy
2039 * of it in case we decide we want to dirty it again in this txg.
2040 */
2041 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
2042 dn->dn_object != DMU_META_DNODE_OBJECT &&
2043 db->db_state == DB_CACHED && db->db_data_pending) {
2044 dbuf_dirty_record_t *dr = db->db_data_pending;
2045
2046 if (dr->dt.dl.dr_data == db->db_buf) {
2047 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2048
2049 dbuf_set_data(db,
2050 arc_buf_alloc(dn->dn_objset->os_spa,
2051 db->db.db_size, db, type));
2052 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data,
2053 db->db.db_size);
2054 }
2055 }
2056
2057 (void) refcount_add(&db->db_holds, tag);
2058 DBUF_VERIFY(db);
2059 mutex_exit(&db->db_mtx);
2060
2061 /* NOTE: we can't rele the parent until after we drop the db_mtx */
2062 if (parent)
2063 dbuf_rele(parent, NULL);
2064
2065 ASSERT3P(DB_DNODE(db), ==, dn);
2066 ASSERT3U(db->db_blkid, ==, blkid);
2067 ASSERT3U(db->db_level, ==, level);
2068 *dbp = db;
2069
2070 return (0);
2071 }
2072
2073 dmu_buf_impl_t *
2074 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
2075 {
2076 dmu_buf_impl_t *db;
2077 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
2078 return (err ? NULL : db);
2079 }
2080
2081 dmu_buf_impl_t *
2082 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
2083 {
2084 dmu_buf_impl_t *db;
2085 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
2086 return (err ? NULL : db);
2087 }
2088
2089 void
2090 dbuf_create_bonus(dnode_t *dn)
2091 {
2092 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
2093
2094 ASSERT(dn->dn_bonus == NULL);
2095 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL);
2096 }
2097
2098 int
2099 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx)
2100 {
2101 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2102 dnode_t *dn;
2103
2104 if (db->db_blkid != DMU_SPILL_BLKID)
2105 return (SET_ERROR(ENOTSUP));
2106 if (blksz == 0)
2107 blksz = SPA_MINBLOCKSIZE;
2108 ASSERT3U(blksz, <=, spa_maxblocksize(dmu_objset_spa(db->db_objset)));
2109 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE);
2110
2111 DB_DNODE_ENTER(db);
2112 dn = DB_DNODE(db);
2113 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
2114 dbuf_new_size(db, blksz, tx);
2115 rw_exit(&dn->dn_struct_rwlock);
2116 DB_DNODE_EXIT(db);
2117
2118 return (0);
2119 }
2120
2121 void
2122 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx)
2123 {
2124 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx);
2125 }
2126
2127 #pragma weak dmu_buf_add_ref = dbuf_add_ref
2128 void
2129 dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
2130 {
2131 int64_t holds = refcount_add(&db->db_holds, tag);
2132 ASSERT(holds > 1);
2133 }
2134
2135 #pragma weak dmu_buf_try_add_ref = dbuf_try_add_ref
2136 boolean_t
2137 dbuf_try_add_ref(dmu_buf_t *db_fake, objset_t *os, uint64_t obj, uint64_t blkid,
2138 void *tag)
2139 {
2140 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2141 dmu_buf_impl_t *found_db;
2142 boolean_t result = B_FALSE;
2143
2144 if (db->db_blkid == DMU_BONUS_BLKID)
2145 found_db = dbuf_find_bonus(os, obj);
2146 else
2147 found_db = dbuf_find(os, obj, 0, blkid);
2148
2149 if (found_db != NULL) {
2150 if (db == found_db && dbuf_refcount(db) > db->db_dirtycnt) {
2151 (void) refcount_add(&db->db_holds, tag);
2152 result = B_TRUE;
2153 }
2154 mutex_exit(&db->db_mtx);
2155 }
2156 return (result);
2157 }
2158
2159 /*
2160 * If you call dbuf_rele() you had better not be referencing the dnode handle
2161 * unless you have some other direct or indirect hold on the dnode. (An indirect
2162 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.)
2163 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the
2164 * dnode's parent dbuf evicting its dnode handles.
2165 */
2166 void
2167 dbuf_rele(dmu_buf_impl_t *db, void *tag)
2168 {
2169 mutex_enter(&db->db_mtx);
2170 dbuf_rele_and_unlock(db, tag);
2171 }
2172
2173 void
2174 dmu_buf_rele(dmu_buf_t *db, void *tag)
2175 {
2176 dbuf_rele((dmu_buf_impl_t *)db, tag);
2177 }
2178
2179 /*
2180 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
2181 * db_dirtycnt and db_holds to be updated atomically.
2182 */
2183 void
2184 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
2185 {
2186 int64_t holds;
2187
2188 ASSERT(MUTEX_HELD(&db->db_mtx));
2189 DBUF_VERIFY(db);
2190
2191 /*
2192 * Remove the reference to the dbuf before removing its hold on the
2193 * dnode so we can guarantee in dnode_move() that a referenced bonus
2194 * buffer has a corresponding dnode hold.
2195 */
2196 holds = refcount_remove(&db->db_holds, tag);
2197 ASSERT(holds >= 0);
2198
2199 /*
2200 * We can't freeze indirects if there is a possibility that they
2201 * may be modified in the current syncing context.
2202 */
2203 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
2204 arc_buf_freeze(db->db_buf);
2205
2206 if (holds == db->db_dirtycnt &&
2207 db->db_level == 0 && db->db_immediate_evict)
2208 dbuf_evict_user(db);
2209
2210 if (holds == 0) {
2211 if (db->db_blkid == DMU_BONUS_BLKID) {
2212 dnode_t *dn;
2213
2214 /*
2215 * If the dnode moves here, we cannot cross this
2216 * barrier until the move completes.
2217 */
2218 DB_DNODE_ENTER(db);
2219
2220 dn = DB_DNODE(db);
2221 atomic_dec_32(&dn->dn_dbufs_count);
2222
2223 /*
2224 * Decrementing the dbuf count means that the bonus
2225 * buffer's dnode hold is no longer discounted in
2226 * dnode_move(). The dnode cannot move until after
2227 * the dnode_rele_and_unlock() below.
2228 */
2229 DB_DNODE_EXIT(db);
2230
2231 /*
2232 * Do not reference db after its lock is dropped.
2233 * Another thread may evict it.
2234 */
2235 mutex_exit(&db->db_mtx);
2236
2237 /*
2238 * If the dnode has been freed, evict the bonus
2239 * buffer immediately. The data in the bonus
2240 * buffer is no longer relevant and this prevents
2241 * a stale bonus buffer from being associated
2242 * with this dnode_t should the dnode_t be reused
2243 * prior to being destroyed.
2244 */
2245 mutex_enter(&dn->dn_mtx);
2246 if (dn->dn_type == DMU_OT_NONE ||
2247 dn->dn_free_txg != 0) {
2248 /*
2249 * Drop dn_mtx. It is a leaf lock and
2250 * cannot be held when dnode_evict_bonus()
2251 * acquires other locks in order to
2252 * perform the eviction.
2253 *
2254 * Freed dnodes cannot be reused until the
2255 * last hold is released. Since this bonus
2256 * buffer has a hold, the dnode will remain
2257 * in the free state, even without dn_mtx
2258 * held, until the dnode_rele_and_unlock()
2259 * below.
2260 */
2261 mutex_exit(&dn->dn_mtx);
2262 dnode_evict_bonus(dn);
2263 mutex_enter(&dn->dn_mtx);
2264 }
2265 dnode_rele_and_unlock(dn, db);
2266 } else if (db->db_buf == NULL) {
2267 /*
2268 * This is a special case: we never associated this
2269 * dbuf with any data allocated from the ARC.
2270 */
2271 ASSERT(db->db_state == DB_UNCACHED ||
2272 db->db_state == DB_NOFILL);
2273 dbuf_evict(db);
2274 } else if (arc_released(db->db_buf)) {
2275 arc_buf_t *buf = db->db_buf;
2276 /*
2277 * This dbuf has anonymous data associated with it.
2278 */
2279 dbuf_clear_data(db);
2280 VERIFY(arc_buf_remove_ref(buf, db));
2281 dbuf_evict(db);
2282 } else {
2283 VERIFY(!arc_buf_remove_ref(db->db_buf, db));
2284
2285 /*
2286 * A dbuf will be eligible for eviction if either the
2287 * 'primarycache' property is set or a duplicate
2288 * copy of this buffer is already cached in the arc.
2289 *
2290 * In the case of the 'primarycache' a buffer
2291 * is considered for eviction if it matches the
2292 * criteria set in the property.
2293 *
2294 * To decide if our buffer is considered a
2295 * duplicate, we must call into the arc to determine
2296 * if multiple buffers are referencing the same
2297 * block on-disk. If so, then we simply evict
2298 * ourselves.
2299 */
2300 if (!DBUF_IS_CACHEABLE(db)) {
2301 if (db->db_blkptr != NULL &&
2302 !BP_IS_HOLE(db->db_blkptr) &&
2303 !BP_IS_EMBEDDED(db->db_blkptr)) {
2304 spa_t *spa =
2305 dmu_objset_spa(db->db_objset);
2306 blkptr_t bp = *db->db_blkptr;
2307 dbuf_clear(db);
2308 arc_freed(spa, &bp);
2309 } else {
2310 dbuf_clear(db);
2311 }
2312 } else if (db->db_objset->os_evicting ||
2313 arc_buf_eviction_needed(db->db_buf)) {
2314 dbuf_clear(db);
2315 } else {
2316 mutex_exit(&db->db_mtx);
2317 }
2318 }
2319 } else {
2320 mutex_exit(&db->db_mtx);
2321 }
2322 }
2323
2324 #pragma weak dmu_buf_refcount = dbuf_refcount
2325 uint64_t
2326 dbuf_refcount(dmu_buf_impl_t *db)
2327 {
2328 return (refcount_count(&db->db_holds));
2329 }
2330
2331 void *
2332 dmu_buf_replace_user(dmu_buf_t *db_fake, dmu_buf_user_t *old_user,
2333 dmu_buf_user_t *new_user)
2334 {
2335 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2336
2337 mutex_enter(&db->db_mtx);
2338 dbuf_verify_user(db, DBVU_NOT_EVICTING);
2339 if (db->db_user == old_user)
2340 db->db_user = new_user;
2341 else
2342 old_user = db->db_user;
2343 dbuf_verify_user(db, DBVU_NOT_EVICTING);
2344 mutex_exit(&db->db_mtx);
2345
2346 return (old_user);
2347 }
2348
2349 void *
2350 dmu_buf_set_user(dmu_buf_t *db_fake, dmu_buf_user_t *user)
2351 {
2352 return (dmu_buf_replace_user(db_fake, NULL, user));
2353 }
2354
2355 void *
2356 dmu_buf_set_user_ie(dmu_buf_t *db_fake, dmu_buf_user_t *user)
2357 {
2358 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2359
2360 db->db_immediate_evict = TRUE;
2361 return (dmu_buf_set_user(db_fake, user));
2362 }
2363
2364 void *
2365 dmu_buf_remove_user(dmu_buf_t *db_fake, dmu_buf_user_t *user)
2366 {
2367 return (dmu_buf_replace_user(db_fake, user, NULL));
2368 }
2369
2370 void *
2371 dmu_buf_get_user(dmu_buf_t *db_fake)
2372 {
2373 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2374
2375 dbuf_verify_user(db, DBVU_NOT_EVICTING);
2376 return (db->db_user);
2377 }
2378
2379 void
2380 dmu_buf_user_evict_wait()
2381 {
2382 taskq_wait(dbu_evict_taskq);
2383 }
2384
2385 boolean_t
2386 dmu_buf_freeable(dmu_buf_t *dbuf)
2387 {
2388 boolean_t res = B_FALSE;
2389 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
2390
2391 if (db->db_blkptr)
2392 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
2393 db->db_blkptr, db->db_blkptr->blk_birth);
2394
2395 return (res);
2396 }
2397
2398 blkptr_t *
2399 dmu_buf_get_blkptr(dmu_buf_t *db)
2400 {
2401 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db;
2402 return (dbi->db_blkptr);
2403 }
2404
2405 static void
2406 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
2407 {
2408 /* ASSERT(dmu_tx_is_syncing(tx) */
2409 ASSERT(MUTEX_HELD(&db->db_mtx));
2410
2411 if (db->db_blkptr != NULL)
2412 return;
2413
2414 if (db->db_blkid == DMU_SPILL_BLKID) {
2415 db->db_blkptr = &dn->dn_phys->dn_spill;
2416 BP_ZERO(db->db_blkptr);
2417 return;
2418 }
2419 if (db->db_level == dn->dn_phys->dn_nlevels-1) {
2420 /*
2421 * This buffer was allocated at a time when there was
2422 * no available blkptrs from the dnode, or it was
2423 * inappropriate to hook it in (i.e., nlevels mis-match).
2424 */
2425 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr);
2426 ASSERT(db->db_parent == NULL);
2427 db->db_parent = dn->dn_dbuf;
2428 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid];
2429 DBUF_VERIFY(db);
2430 } else {
2431 dmu_buf_impl_t *parent = db->db_parent;
2432 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2433
2434 ASSERT(dn->dn_phys->dn_nlevels > 1);
2435 if (parent == NULL) {
2436 mutex_exit(&db->db_mtx);
2437 rw_enter(&dn->dn_struct_rwlock, RW_READER);
2438 (void) dbuf_hold_impl(dn, db->db_level+1,
2439 db->db_blkid >> epbs, FALSE, db, &parent);
2440 rw_exit(&dn->dn_struct_rwlock);
2441 mutex_enter(&db->db_mtx);
2442 db->db_parent = parent;
2443 }
2444 db->db_blkptr = (blkptr_t *)parent->db.db_data +
2445 (db->db_blkid & ((1ULL << epbs) - 1));
2446 DBUF_VERIFY(db);
2447 }
2448 }
2449
2450 static void
2451 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2452 {
2453 dmu_buf_impl_t *db = dr->dr_dbuf;
2454 dnode_t *dn;
2455 zio_t *zio;
2456
2457 ASSERT(dmu_tx_is_syncing(tx));
2458
2459 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2460
2461 mutex_enter(&db->db_mtx);
2462
2463 ASSERT(db->db_level > 0);
2464 DBUF_VERIFY(db);
2465
2466 /* Read the block if it hasn't been read yet. */
2467 if (db->db_buf == NULL) {
2468 mutex_exit(&db->db_mtx);
2469 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
2470 mutex_enter(&db->db_mtx);
2471 }
2472 ASSERT3U(db->db_state, ==, DB_CACHED);
2473 ASSERT(db->db_buf != NULL);
2474
2475 DB_DNODE_ENTER(db);
2476 dn = DB_DNODE(db);
2477 /* Indirect block size must match what the dnode thinks it is. */
2478 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2479 dbuf_check_blkptr(dn, db);
2480 DB_DNODE_EXIT(db);
2481
2482 /* Provide the pending dirty record to child dbufs */
2483 db->db_data_pending = dr;
2484
2485 mutex_exit(&db->db_mtx);
2486 dbuf_write(dr, db->db_buf, tx);
2487
2488 zio = dr->dr_zio;
2489 mutex_enter(&dr->dt.di.dr_mtx);
2490 dbuf_sync_list(&dr->dt.di.dr_children, tx);
2491 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2492 mutex_exit(&dr->dt.di.dr_mtx);
2493 zio_nowait(zio);
2494 }
2495
2496 static void
2497 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2498 {
2499 arc_buf_t **datap = &dr->dt.dl.dr_data;
2500 dmu_buf_impl_t *db = dr->dr_dbuf;
2501 dnode_t *dn;
2502 objset_t *os;
2503 uint64_t txg = tx->tx_txg;
2504
2505 ASSERT(dmu_tx_is_syncing(tx));
2506
2507 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2508
2509 mutex_enter(&db->db_mtx);
2510 /*
2511 * To be synced, we must be dirtied. But we
2512 * might have been freed after the dirty.
2513 */
2514 if (db->db_state == DB_UNCACHED) {
2515 /* This buffer has been freed since it was dirtied */
2516 ASSERT(db->db.db_data == NULL);
2517 } else if (db->db_state == DB_FILL) {
2518 /* This buffer was freed and is now being re-filled */
2519 ASSERT(db->db.db_data != dr->dt.dl.dr_data);
2520 } else {
2521 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL);
2522 }
2523 DBUF_VERIFY(db);
2524
2525 DB_DNODE_ENTER(db);
2526 dn = DB_DNODE(db);
2527
2528 if (db->db_blkid == DMU_SPILL_BLKID) {
2529 mutex_enter(&dn->dn_mtx);
2530 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR;
2531 mutex_exit(&dn->dn_mtx);
2532 }
2533
2534 /*
2535 * If this is a bonus buffer, simply copy the bonus data into the
2536 * dnode. It will be written out when the dnode is synced (and it
2537 * will be synced, since it must have been dirty for dbuf_sync to
2538 * be called).
2539 */
2540 if (db->db_blkid == DMU_BONUS_BLKID) {
2541 dbuf_dirty_record_t **drp;
2542
2543 ASSERT(*datap != NULL);
2544 ASSERT0(db->db_level);
2545 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
2546 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
2547 DB_DNODE_EXIT(db);
2548
2549 if (*datap != db->db.db_data) {
2550 zio_buf_free(*datap, DN_MAX_BONUSLEN);
2551 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
2552 }
2553 db->db_data_pending = NULL;
2554 drp = &db->db_last_dirty;
2555 while (*drp != dr)
2556 drp = &(*drp)->dr_next;
2557 ASSERT(dr->dr_next == NULL);
2558 ASSERT(dr->dr_dbuf == db);
2559 *drp = dr->dr_next;
2560 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2561 ASSERT(db->db_dirtycnt > 0);
2562 db->db_dirtycnt -= 1;
2563 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2564 return;
2565 }
2566
2567 os = dn->dn_objset;
2568
2569 /*
2570 * This function may have dropped the db_mtx lock allowing a dmu_sync
2571 * operation to sneak in. As a result, we need to ensure that we
2572 * don't check the dr_override_state until we have returned from
2573 * dbuf_check_blkptr.
2574 */
2575 dbuf_check_blkptr(dn, db);
2576
2577 /*
2578 * If this buffer is in the middle of an immediate write,
2579 * wait for the synchronous IO to complete.
2580 */
2581 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
2582 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
2583 cv_wait(&db->db_changed, &db->db_mtx);
2584 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
2585 }
2586
2587 if (db->db_state != DB_NOFILL &&
2588 dn->dn_object != DMU_META_DNODE_OBJECT &&
2589 refcount_count(&db->db_holds) > 1 &&
2590 dr->dt.dl.dr_override_state != DR_OVERRIDDEN &&
2591 *datap == db->db_buf) {
2592 /*
2593 * If this buffer is currently "in use" (i.e., there
2594 * are active holds and db_data still references it),
2595 * then make a copy before we start the write so that
2596 * any modifications from the open txg will not leak
2597 * into this write.
2598 *
2599 * NOTE: this copy does not need to be made for
2600 * objects only modified in the syncing context (e.g.
2601 * DNONE_DNODE blocks).
2602 */
2603 int blksz = arc_buf_size(*datap);
2604 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2605 *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
2606 bcopy(db->db.db_data, (*datap)->b_data, blksz);
2607 }
2608 db->db_data_pending = dr;
2609
2610 mutex_exit(&db->db_mtx);
2611
2612 dbuf_write(dr, *datap, tx);
2613
2614 ASSERT(!list_link_active(&dr->dr_dirty_node));
2615 if (dn->dn_object == DMU_META_DNODE_OBJECT) {
2616 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr);
2617 DB_DNODE_EXIT(db);
2618 } else {
2619 /*
2620 * Although zio_nowait() does not "wait for an IO", it does
2621 * initiate the IO. If this is an empty write it seems plausible
2622 * that the IO could actually be completed before the nowait
2623 * returns. We need to DB_DNODE_EXIT() first in case
2624 * zio_nowait() invalidates the dbuf.
2625 */
2626 DB_DNODE_EXIT(db);
2627 zio_nowait(dr->dr_zio);
2628 }
2629 }
2630
2631 void
2632 dbuf_sync_list(list_t *list, dmu_tx_t *tx)
2633 {
2634 dbuf_dirty_record_t *dr;
2635
2636 while (dr = list_head(list)) {
2637 if (dr->dr_zio != NULL) {
2638 /*
2639 * If we find an already initialized zio then we
2640 * are processing the meta-dnode, and we have finished.
2641 * The dbufs for all dnodes are put back on the list
2642 * during processing, so that we can zio_wait()
2643 * these IOs after initiating all child IOs.
2644 */
2645 ASSERT3U(dr->dr_dbuf->db.db_object, ==,
2646 DMU_META_DNODE_OBJECT);
2647 break;
2648 }
2649 list_remove(list, dr);
2650 if (dr->dr_dbuf->db_level > 0)
2651 dbuf_sync_indirect(dr, tx);
2652 else
2653 dbuf_sync_leaf(dr, tx);
2654 }
2655 }
2656
2657 /* ARGSUSED */
2658 static void
2659 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
2660 {
2661 dmu_buf_impl_t *db = vdb;
2662 dnode_t *dn;
2663 blkptr_t *bp = zio->io_bp;
2664 blkptr_t *bp_orig = &zio->io_bp_orig;
2665 spa_t *spa = zio->io_spa;
2666 int64_t delta;
2667 uint64_t fill = 0;
2668 int i;
2669
2670 ASSERT3P(db->db_blkptr, !=, NULL);
2671 ASSERT3P(&db->db_data_pending->dr_bp_copy, ==, bp);
2672
2673 DB_DNODE_ENTER(db);
2674 dn = DB_DNODE(db);
2675 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig);
2676 dnode_diduse_space(dn, delta - zio->io_prev_space_delta);
2677 zio->io_prev_space_delta = delta;
2678
2679 if (bp->blk_birth != 0) {
2680 ASSERT((db->db_blkid != DMU_SPILL_BLKID &&
2681 BP_GET_TYPE(bp) == dn->dn_type) ||
2682 (db->db_blkid == DMU_SPILL_BLKID &&
2683 BP_GET_TYPE(bp) == dn->dn_bonustype) ||
2684 BP_IS_EMBEDDED(bp));
2685 ASSERT(BP_GET_LEVEL(bp) == db->db_level);
2686 }
2687
2688 mutex_enter(&db->db_mtx);
2689
2690 #ifdef ZFS_DEBUG
2691 if (db->db_blkid == DMU_SPILL_BLKID) {
2692 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2693 ASSERT(!(BP_IS_HOLE(bp)) &&
2694 db->db_blkptr == &dn->dn_phys->dn_spill);
2695 }
2696 #endif
2697
2698 if (db->db_level == 0) {
2699 mutex_enter(&dn->dn_mtx);
2700 if (db->db_blkid > dn->dn_phys->dn_maxblkid &&
2701 db->db_blkid != DMU_SPILL_BLKID)
2702 dn->dn_phys->dn_maxblkid = db->db_blkid;
2703 mutex_exit(&dn->dn_mtx);
2704
2705 if (dn->dn_type == DMU_OT_DNODE) {
2706 dnode_phys_t *dnp = db->db.db_data;
2707 for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
2708 i--, dnp++) {
2709 if (dnp->dn_type != DMU_OT_NONE)
2710 fill++;
2711 }
2712 } else {
2713 if (BP_IS_HOLE(bp)) {
2714 fill = 0;
2715 } else {
2716 fill = 1;
2717 }
2718 }
2719 } else {
2720 blkptr_t *ibp = db->db.db_data;
2721 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2722 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
2723 if (BP_IS_HOLE(ibp))
2724 continue;
2725 fill += BP_GET_FILL(ibp);
2726 }
2727 }
2728 DB_DNODE_EXIT(db);
2729
2730 if (!BP_IS_EMBEDDED(bp))
2731 bp->blk_fill = fill;
2732
2733 mutex_exit(&db->db_mtx);
2734
2735 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
2736 *db->db_blkptr = *bp;
2737 rw_exit(&dn->dn_struct_rwlock);
2738 }
2739
2740 /*
2741 * The SPA will call this callback several times for each zio - once
2742 * for every physical child i/o (zio->io_phys_children times). This
2743 * allows the DMU to monitor the progress of each logical i/o. For example,
2744 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z
2745 * block. There may be a long delay before all copies/fragments are completed,
2746 * so this callback allows us to retire dirty space gradually, as the physical
2747 * i/os complete.
2748 */
2749 /* ARGSUSED */
2750 static void
2751 dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg)
2752 {
2753 dmu_buf_impl_t *db = arg;
2754 objset_t *os = db->db_objset;
2755 dsl_pool_t *dp = dmu_objset_pool(os);
2756 dbuf_dirty_record_t *dr;
2757 int delta = 0;
2758
2759 dr = db->db_data_pending;
2760 ASSERT3U(dr->dr_txg, ==, zio->io_txg);
2761
2762 /*
2763 * The callback will be called io_phys_children times. Retire one
2764 * portion of our dirty space each time we are called. Any rounding
2765 * error will be cleaned up by dsl_pool_sync()'s call to
2766 * dsl_pool_undirty_space().
2767 */
2768 delta = dr->dr_accounted / zio->io_phys_children;
2769 dsl_pool_undirty_space(dp, delta, zio->io_txg);
2770 }
2771
2772 /* ARGSUSED */
2773 static void
2774 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
2775 {
2776 dmu_buf_impl_t *db = vdb;
2777 blkptr_t *bp_orig = &zio->io_bp_orig;
2778 blkptr_t *bp = db->db_blkptr;
2779 objset_t *os = db->db_objset;
2780 dmu_tx_t *tx = os->os_synctx;
2781 dbuf_dirty_record_t **drp, *dr;
2782
2783 ASSERT0(zio->io_error);
2784 ASSERT(db->db_blkptr == bp);
2785
2786 /*
2787 * For nopwrites and rewrites we ensure that the bp matches our
2788 * original and bypass all the accounting.
2789 */
2790 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) {
2791 ASSERT(BP_EQUAL(bp, bp_orig));
2792 } else {
2793 dsl_dataset_t *ds = os->os_dsl_dataset;
2794 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
2795 dsl_dataset_block_born(ds, bp, tx);
2796 }
2797
2798 mutex_enter(&db->db_mtx);
2799
2800 DBUF_VERIFY(db);
2801
2802 drp = &db->db_last_dirty;
2803 while ((dr = *drp) != db->db_data_pending)
2804 drp = &dr->dr_next;
2805 ASSERT(!list_link_active(&dr->dr_dirty_node));
2806 ASSERT(dr->dr_dbuf == db);
2807 ASSERT(dr->dr_next == NULL);
2808 *drp = dr->dr_next;
2809
2810 #ifdef ZFS_DEBUG
2811 if (db->db_blkid == DMU_SPILL_BLKID) {
2812 dnode_t *dn;
2813
2814 DB_DNODE_ENTER(db);
2815 dn = DB_DNODE(db);
2816 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2817 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2818 db->db_blkptr == &dn->dn_phys->dn_spill);
2819 DB_DNODE_EXIT(db);
2820 }
2821 #endif
2822
2823 if (db->db_level == 0) {
2824 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
2825 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
2826 if (db->db_state != DB_NOFILL) {
2827 if (dr->dt.dl.dr_data != db->db_buf)
2828 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
2829 db));
2830 else if (!arc_released(db->db_buf))
2831 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2832 }
2833 } else {
2834 dnode_t *dn;
2835
2836 DB_DNODE_ENTER(db);
2837 dn = DB_DNODE(db);
2838 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2839 ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift);
2840 if (!BP_IS_HOLE(db->db_blkptr)) {
2841 int epbs =
2842 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2843 ASSERT3U(db->db_blkid, <=,
2844 dn->dn_phys->dn_maxblkid >> (db->db_level * epbs));
2845 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
2846 db->db.db_size);
2847 if (!arc_released(db->db_buf))
2848 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2849 }
2850 DB_DNODE_EXIT(db);
2851 mutex_destroy(&dr->dt.di.dr_mtx);
2852 list_destroy(&dr->dt.di.dr_children);
2853 }
2854 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2855
2856 cv_broadcast(&db->db_changed);
2857 ASSERT(db->db_dirtycnt > 0);
2858 db->db_dirtycnt -= 1;
2859 db->db_data_pending = NULL;
2860 dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg);
2861 }
2862
2863 static void
2864 dbuf_write_nofill_ready(zio_t *zio)
2865 {
2866 dbuf_write_ready(zio, NULL, zio->io_private);
2867 }
2868
2869 static void
2870 dbuf_write_nofill_done(zio_t *zio)
2871 {
2872 dbuf_write_done(zio, NULL, zio->io_private);
2873 }
2874
2875 static void
2876 dbuf_write_override_ready(zio_t *zio)
2877 {
2878 dbuf_dirty_record_t *dr = zio->io_private;
2879 dmu_buf_impl_t *db = dr->dr_dbuf;
2880
2881 dbuf_write_ready(zio, NULL, db);
2882 }
2883
2884 static void
2885 dbuf_write_override_done(zio_t *zio)
2886 {
2887 dbuf_dirty_record_t *dr = zio->io_private;
2888 dmu_buf_impl_t *db = dr->dr_dbuf;
2889 blkptr_t *obp = &dr->dt.dl.dr_overridden_by;
2890
2891 mutex_enter(&db->db_mtx);
2892 if (!BP_EQUAL(zio->io_bp, obp)) {
2893 if (!BP_IS_HOLE(obp))
2894 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp);
2895 arc_release(dr->dt.dl.dr_data, db);
2896 }
2897 mutex_exit(&db->db_mtx);
2898
2899 dbuf_write_done(zio, NULL, db);
2900 }
2901
2902 /* Issue I/O to commit a dirty buffer to disk. */
2903 static void
2904 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
2905 {
2906 dmu_buf_impl_t *db = dr->dr_dbuf;
2907 dnode_t *dn;
2908 objset_t *os;
2909 dmu_buf_impl_t *parent = db->db_parent;
2910 uint64_t txg = tx->tx_txg;
2911 zbookmark_phys_t zb;
2912 zio_prop_t zp;
2913 zio_t *zio;
2914 int wp_flag = 0;
2915
2916 ASSERT(dmu_tx_is_syncing(tx));
2917
2918 DB_DNODE_ENTER(db);
2919 dn = DB_DNODE(db);
2920 os = dn->dn_objset;
2921
2922 if (db->db_state != DB_NOFILL) {
2923 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) {
2924 /*
2925 * Private object buffers are released here rather
2926 * than in dbuf_dirty() since they are only modified
2927 * in the syncing context and we don't want the
2928 * overhead of making multiple copies of the data.
2929 */
2930 if (BP_IS_HOLE(db->db_blkptr)) {
2931 arc_buf_thaw(data);
2932 } else {
2933 dbuf_release_bp(db);
2934 }
2935 }
2936 }
2937
2938 if (parent != dn->dn_dbuf) {
2939 /* Our parent is an indirect block. */
2940 /* We have a dirty parent that has been scheduled for write. */
2941 ASSERT(parent && parent->db_data_pending);
2942 /* Our parent's buffer is one level closer to the dnode. */
2943 ASSERT(db->db_level == parent->db_level-1);
2944 /*
2945 * We're about to modify our parent's db_data by modifying
2946 * our block pointer, so the parent must be released.
2947 */
2948 ASSERT(arc_released(parent->db_buf));
2949 zio = parent->db_data_pending->dr_zio;
2950 } else {
2951 /* Our parent is the dnode itself. */
2952 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 &&
2953 db->db_blkid != DMU_SPILL_BLKID) ||
2954 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0));
2955 if (db->db_blkid != DMU_SPILL_BLKID)
2956 ASSERT3P(db->db_blkptr, ==,
2957 &dn->dn_phys->dn_blkptr[db->db_blkid]);
2958 zio = dn->dn_zio;
2959 }
2960
2961 ASSERT(db->db_level == 0 || data == db->db_buf);
2962 ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
2963 ASSERT(zio);
2964
2965 SET_BOOKMARK(&zb, os->os_dsl_dataset ?
2966 os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
2967 db->db.db_object, db->db_level, db->db_blkid);
2968
2969 if (db->db_blkid == DMU_SPILL_BLKID)
2970 wp_flag = WP_SPILL;
2971 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0;
2972
2973 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp);
2974 DB_DNODE_EXIT(db);
2975
2976 /*
2977 * We copy the blkptr now (rather than when we instantiate the dirty
2978 * record), because its value can change between open context and
2979 * syncing context. We do not need to hold dn_struct_rwlock to read
2980 * db_blkptr because we are in syncing context.
2981 */
2982 dr->dr_bp_copy = *db->db_blkptr;
2983
2984 if (db->db_level == 0 &&
2985 dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
2986 /*
2987 * The BP for this block has been provided by open context
2988 * (by dmu_sync() or dmu_buf_write_embedded()).
2989 */
2990 void *contents = (data != NULL) ? data->b_data : NULL;
2991
2992 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2993 &dr->dr_bp_copy, contents, db->db.db_size, &zp,
2994 dbuf_write_override_ready, NULL, dbuf_write_override_done,
2995 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2996 mutex_enter(&db->db_mtx);
2997 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
2998 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by,
2999 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite);
3000 mutex_exit(&db->db_mtx);
3001 } else if (db->db_state == DB_NOFILL) {
3002 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF ||
3003 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY);
3004 dr->dr_zio = zio_write(zio, os->os_spa, txg,
3005 &dr->dr_bp_copy, NULL, db->db.db_size, &zp,
3006 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db,
3007 ZIO_PRIORITY_ASYNC_WRITE,
3008 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb);
3009 } else {
3010 ASSERT(arc_released(data));
3011 dr->dr_zio = arc_write(zio, os->os_spa, txg,
3012 &dr->dr_bp_copy, data, DBUF_IS_L2CACHEABLE(db),
3013 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready,
3014 dbuf_write_physdone, dbuf_write_done, db,
3015 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
3016 }
3017 }