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.
| 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.
| 24 * Copyright (c) 2012, 2015 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 */
28
29#include <sys/zfs_context.h>
30#include <sys/dmu.h>
31#include <sys/dmu_send.h>
32#include <sys/dmu_impl.h>
33#include <sys/dbuf.h>
34#include <sys/dmu_objset.h>
35#include <sys/dsl_dataset.h>
36#include <sys/dsl_dir.h>
37#include <sys/dmu_tx.h>
38#include <sys/spa.h>
39#include <sys/zio.h>
40#include <sys/dmu_zfetch.h>
41#include <sys/sa.h>
42#include <sys/sa_impl.h>
43#include <sys/zfeature.h>
44#include <sys/blkptr.h>
45#include <sys/range_tree.h>
46
47/*
48 * Number of times that zfs_free_range() took the slow path while doing
49 * a zfs receive. A nonzero value indicates a potential performance problem.
50 */
51uint64_t zfs_free_range_recv_miss;
52
53static void dbuf_destroy(dmu_buf_impl_t *db);
54static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
55static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
56
57/*
58 * Global data structures and functions for the dbuf cache.
59 */
60static kmem_cache_t *dbuf_cache;
61
62/* ARGSUSED */
63static int
64dbuf_cons(void *vdb, void *unused, int kmflag)
65{
66 dmu_buf_impl_t *db = vdb;
67 bzero(db, sizeof (dmu_buf_impl_t));
68
69 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
70 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
71 refcount_create(&db->db_holds);
72
73 return (0);
74}
75
76/* ARGSUSED */
77static void
78dbuf_dest(void *vdb, void *unused)
79{
80 dmu_buf_impl_t *db = vdb;
81 mutex_destroy(&db->db_mtx);
82 cv_destroy(&db->db_changed);
83 refcount_destroy(&db->db_holds);
84}
85
86/*
87 * dbuf hash table routines
88 */
89static dbuf_hash_table_t dbuf_hash_table;
90
91static uint64_t dbuf_hash_count;
92
93static uint64_t
94dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
95{
96 uintptr_t osv = (uintptr_t)os;
97 uint64_t crc = -1ULL;
98
99 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
100 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
101 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
102 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
103 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
104 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
105 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
106
107 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
108
109 return (crc);
110}
111
112#define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
113
114#define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
115 ((dbuf)->db.db_object == (obj) && \
116 (dbuf)->db_objset == (os) && \
117 (dbuf)->db_level == (level) && \
118 (dbuf)->db_blkid == (blkid))
119
120dmu_buf_impl_t *
121dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
122{
123 dbuf_hash_table_t *h = &dbuf_hash_table;
124 objset_t *os = dn->dn_objset;
125 uint64_t obj = dn->dn_object;
126 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
127 uint64_t idx = hv & h->hash_table_mask;
128 dmu_buf_impl_t *db;
129
130 mutex_enter(DBUF_HASH_MUTEX(h, idx));
131 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
132 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
133 mutex_enter(&db->db_mtx);
134 if (db->db_state != DB_EVICTING) {
135 mutex_exit(DBUF_HASH_MUTEX(h, idx));
136 return (db);
137 }
138 mutex_exit(&db->db_mtx);
139 }
140 }
141 mutex_exit(DBUF_HASH_MUTEX(h, idx));
142 return (NULL);
143}
144
145/*
146 * Insert an entry into the hash table. If there is already an element
147 * equal to elem in the hash table, then the already existing element
148 * will be returned and the new element will not be inserted.
149 * Otherwise returns NULL.
150 */
151static dmu_buf_impl_t *
152dbuf_hash_insert(dmu_buf_impl_t *db)
153{
154 dbuf_hash_table_t *h = &dbuf_hash_table;
155 objset_t *os = db->db_objset;
156 uint64_t obj = db->db.db_object;
157 int level = db->db_level;
158 uint64_t blkid = db->db_blkid;
159 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
160 uint64_t idx = hv & h->hash_table_mask;
161 dmu_buf_impl_t *dbf;
162
163 mutex_enter(DBUF_HASH_MUTEX(h, idx));
164 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
165 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
166 mutex_enter(&dbf->db_mtx);
167 if (dbf->db_state != DB_EVICTING) {
168 mutex_exit(DBUF_HASH_MUTEX(h, idx));
169 return (dbf);
170 }
171 mutex_exit(&dbf->db_mtx);
172 }
173 }
174
175 mutex_enter(&db->db_mtx);
176 db->db_hash_next = h->hash_table[idx];
177 h->hash_table[idx] = db;
178 mutex_exit(DBUF_HASH_MUTEX(h, idx));
179 atomic_inc_64(&dbuf_hash_count);
180
181 return (NULL);
182}
183
184/*
185 * Remove an entry from the hash table. It must be in the EVICTING state.
186 */
187static void
188dbuf_hash_remove(dmu_buf_impl_t *db)
189{
190 dbuf_hash_table_t *h = &dbuf_hash_table;
191 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object,
192 db->db_level, db->db_blkid);
193 uint64_t idx = hv & h->hash_table_mask;
194 dmu_buf_impl_t *dbf, **dbp;
195
196 /*
197 * We musn't hold db_mtx to maintain lock ordering:
198 * DBUF_HASH_MUTEX > db_mtx.
199 */
200 ASSERT(refcount_is_zero(&db->db_holds));
201 ASSERT(db->db_state == DB_EVICTING);
202 ASSERT(!MUTEX_HELD(&db->db_mtx));
203
204 mutex_enter(DBUF_HASH_MUTEX(h, idx));
205 dbp = &h->hash_table[idx];
206 while ((dbf = *dbp) != db) {
207 dbp = &dbf->db_hash_next;
208 ASSERT(dbf != NULL);
209 }
210 *dbp = db->db_hash_next;
211 db->db_hash_next = NULL;
212 mutex_exit(DBUF_HASH_MUTEX(h, idx));
213 atomic_dec_64(&dbuf_hash_count);
214}
215
216static arc_evict_func_t dbuf_do_evict;
217
218static void
219dbuf_evict_user(dmu_buf_impl_t *db)
220{
221 ASSERT(MUTEX_HELD(&db->db_mtx));
222
223 if (db->db_level != 0 || db->db_evict_func == NULL)
224 return;
225
226 db->db_evict_func(&db->db, db->db_user_ptr);
227 db->db_user_ptr = NULL;
228 db->db_evict_func = NULL;
229}
230
231boolean_t
232dbuf_is_metadata(dmu_buf_impl_t *db)
233{
234 if (db->db_level > 0) {
235 return (B_TRUE);
236 } else {
237 boolean_t is_metadata;
238
239 DB_DNODE_ENTER(db);
240 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type);
241 DB_DNODE_EXIT(db);
242
243 return (is_metadata);
244 }
245}
246
247void
248dbuf_evict(dmu_buf_impl_t *db)
249{
250 ASSERT(MUTEX_HELD(&db->db_mtx));
251 ASSERT(db->db_buf == NULL);
252 ASSERT(db->db_data_pending == NULL);
253
254 dbuf_clear(db);
255 dbuf_destroy(db);
256}
257
258void
259dbuf_init(void)
260{
261 uint64_t hsize = 1ULL << 16;
262 dbuf_hash_table_t *h = &dbuf_hash_table;
263 int i;
264
265 /*
266 * The hash table is big enough to fill all of physical memory
267 * with an average 4K block size. The table will take up
268 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
269 */
270 while (hsize * 4096 < (uint64_t)physmem * PAGESIZE)
271 hsize <<= 1;
272
273retry:
274 h->hash_table_mask = hsize - 1;
275 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
276 if (h->hash_table == NULL) {
277 /* XXX - we should really return an error instead of assert */
278 ASSERT(hsize > (1ULL << 10));
279 hsize >>= 1;
280 goto retry;
281 }
282
283 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
284 sizeof (dmu_buf_impl_t),
285 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
286
287 for (i = 0; i < DBUF_MUTEXES; i++)
288 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
289}
290
291void
292dbuf_fini(void)
293{
294 dbuf_hash_table_t *h = &dbuf_hash_table;
295 int i;
296
297 for (i = 0; i < DBUF_MUTEXES; i++)
298 mutex_destroy(&h->hash_mutexes[i]);
299 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
300 kmem_cache_destroy(dbuf_cache);
301}
302
303/*
304 * Other stuff.
305 */
306
307#ifdef ZFS_DEBUG
308static void
309dbuf_verify(dmu_buf_impl_t *db)
310{
311 dnode_t *dn;
312 dbuf_dirty_record_t *dr;
313
314 ASSERT(MUTEX_HELD(&db->db_mtx));
315
316 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
317 return;
318
319 ASSERT(db->db_objset != NULL);
320 DB_DNODE_ENTER(db);
321 dn = DB_DNODE(db);
322 if (dn == NULL) {
323 ASSERT(db->db_parent == NULL);
324 ASSERT(db->db_blkptr == NULL);
325 } else {
326 ASSERT3U(db->db.db_object, ==, dn->dn_object);
327 ASSERT3P(db->db_objset, ==, dn->dn_objset);
328 ASSERT3U(db->db_level, <, dn->dn_nlevels);
329 ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
330 db->db_blkid == DMU_SPILL_BLKID ||
331 !avl_is_empty(&dn->dn_dbufs));
332 }
333 if (db->db_blkid == DMU_BONUS_BLKID) {
334 ASSERT(dn != NULL);
335 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
336 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID);
337 } else if (db->db_blkid == DMU_SPILL_BLKID) {
338 ASSERT(dn != NULL);
339 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
340 ASSERT0(db->db.db_offset);
341 } else {
342 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
343 }
344
345 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
346 ASSERT(dr->dr_dbuf == db);
347
348 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
349 ASSERT(dr->dr_dbuf == db);
350
351 /*
352 * We can't assert that db_size matches dn_datablksz because it
353 * can be momentarily different when another thread is doing
354 * dnode_set_blksz().
355 */
356 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
357 dr = db->db_data_pending;
358 /*
359 * It should only be modified in syncing context, so
360 * make sure we only have one copy of the data.
361 */
362 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
363 }
364
365 /* verify db->db_blkptr */
366 if (db->db_blkptr) {
367 if (db->db_parent == dn->dn_dbuf) {
368 /* db is pointed to by the dnode */
369 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
370 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
371 ASSERT(db->db_parent == NULL);
372 else
373 ASSERT(db->db_parent != NULL);
374 if (db->db_blkid != DMU_SPILL_BLKID)
375 ASSERT3P(db->db_blkptr, ==,
376 &dn->dn_phys->dn_blkptr[db->db_blkid]);
377 } else {
378 /* db is pointed to by an indirect block */
379 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT;
380 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
381 ASSERT3U(db->db_parent->db.db_object, ==,
382 db->db.db_object);
383 /*
384 * dnode_grow_indblksz() can make this fail if we don't
385 * have the struct_rwlock. XXX indblksz no longer
386 * grows. safe to do this now?
387 */
388 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
389 ASSERT3P(db->db_blkptr, ==,
390 ((blkptr_t *)db->db_parent->db.db_data +
391 db->db_blkid % epb));
392 }
393 }
394 }
395 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
396 (db->db_buf == NULL || db->db_buf->b_data) &&
397 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID &&
398 db->db_state != DB_FILL && !dn->dn_free_txg) {
399 /*
400 * If the blkptr isn't set but they have nonzero data,
401 * it had better be dirty, otherwise we'll lose that
402 * data when we evict this buffer.
403 */
404 if (db->db_dirtycnt == 0) {
405 uint64_t *buf = db->db.db_data;
406 int i;
407
408 for (i = 0; i < db->db.db_size >> 3; i++) {
409 ASSERT(buf[i] == 0);
410 }
411 }
412 }
413 DB_DNODE_EXIT(db);
414}
415#endif
416
417static void
418dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
419{
420 ASSERT(MUTEX_HELD(&db->db_mtx));
421 db->db_buf = buf;
422 if (buf != NULL) {
423 ASSERT(buf->b_data != NULL);
424 db->db.db_data = buf->b_data;
425 if (!arc_released(buf))
426 arc_set_callback(buf, dbuf_do_evict, db);
427 } else {
428 dbuf_evict_user(db);
429 db->db.db_data = NULL;
430 if (db->db_state != DB_NOFILL)
431 db->db_state = DB_UNCACHED;
432 }
433}
434
435/*
436 * Loan out an arc_buf for read. Return the loaned arc_buf.
437 */
438arc_buf_t *
439dbuf_loan_arcbuf(dmu_buf_impl_t *db)
440{
441 arc_buf_t *abuf;
442
443 mutex_enter(&db->db_mtx);
444 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
445 int blksz = db->db.db_size;
446 spa_t *spa = db->db_objset->os_spa;
447
448 mutex_exit(&db->db_mtx);
449 abuf = arc_loan_buf(spa, blksz);
450 bcopy(db->db.db_data, abuf->b_data, blksz);
451 } else {
452 abuf = db->db_buf;
453 arc_loan_inuse_buf(abuf, db);
454 dbuf_set_data(db, NULL);
455 mutex_exit(&db->db_mtx);
456 }
457 return (abuf);
458}
459
460uint64_t
461dbuf_whichblock(dnode_t *dn, uint64_t offset)
462{
463 if (dn->dn_datablkshift) {
464 return (offset >> dn->dn_datablkshift);
465 } else {
466 ASSERT3U(offset, <, dn->dn_datablksz);
467 return (0);
468 }
469}
470
471static void
472dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
473{
474 dmu_buf_impl_t *db = vdb;
475
476 mutex_enter(&db->db_mtx);
477 ASSERT3U(db->db_state, ==, DB_READ);
478 /*
479 * All reads are synchronous, so we must have a hold on the dbuf
480 */
481 ASSERT(refcount_count(&db->db_holds) > 0);
482 ASSERT(db->db_buf == NULL);
483 ASSERT(db->db.db_data == NULL);
484 if (db->db_level == 0 && db->db_freed_in_flight) {
485 /* we were freed in flight; disregard any error */
486 arc_release(buf, db);
487 bzero(buf->b_data, db->db.db_size);
488 arc_buf_freeze(buf);
489 db->db_freed_in_flight = FALSE;
490 dbuf_set_data(db, buf);
491 db->db_state = DB_CACHED;
492 } else if (zio == NULL || zio->io_error == 0) {
493 dbuf_set_data(db, buf);
494 db->db_state = DB_CACHED;
495 } else {
496 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
497 ASSERT3P(db->db_buf, ==, NULL);
498 VERIFY(arc_buf_remove_ref(buf, db));
499 db->db_state = DB_UNCACHED;
500 }
501 cv_broadcast(&db->db_changed);
502 dbuf_rele_and_unlock(db, NULL);
503}
504
505static void
506dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
507{
508 dnode_t *dn;
509 zbookmark_phys_t zb;
510 arc_flags_t aflags = ARC_FLAG_NOWAIT;
511
512 DB_DNODE_ENTER(db);
513 dn = DB_DNODE(db);
514 ASSERT(!refcount_is_zero(&db->db_holds));
515 /* We need the struct_rwlock to prevent db_blkptr from changing. */
516 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
517 ASSERT(MUTEX_HELD(&db->db_mtx));
518 ASSERT(db->db_state == DB_UNCACHED);
519 ASSERT(db->db_buf == NULL);
520
521 if (db->db_blkid == DMU_BONUS_BLKID) {
522 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
523
524 ASSERT3U(bonuslen, <=, db->db.db_size);
525 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
526 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
527 if (bonuslen < DN_MAX_BONUSLEN)
528 bzero(db->db.db_data, DN_MAX_BONUSLEN);
529 if (bonuslen)
530 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
531 DB_DNODE_EXIT(db);
532 db->db_state = DB_CACHED;
533 mutex_exit(&db->db_mtx);
534 return;
535 }
536
537 /*
538 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
539 * processes the delete record and clears the bp while we are waiting
540 * for the dn_mtx (resulting in a "no" from block_freed).
541 */
542 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
543 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
544 BP_IS_HOLE(db->db_blkptr)))) {
545 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
546
547 DB_DNODE_EXIT(db);
548 dbuf_set_data(db, arc_buf_alloc(db->db_objset->os_spa,
549 db->db.db_size, db, type));
550 bzero(db->db.db_data, db->db.db_size);
551 db->db_state = DB_CACHED;
552 *flags |= DB_RF_CACHED;
553 mutex_exit(&db->db_mtx);
554 return;
555 }
556
557 DB_DNODE_EXIT(db);
558
559 db->db_state = DB_READ;
560 mutex_exit(&db->db_mtx);
561
562 if (DBUF_IS_L2CACHEABLE(db))
563 aflags |= ARC_FLAG_L2CACHE;
564 if (DBUF_IS_L2COMPRESSIBLE(db))
565 aflags |= ARC_FLAG_L2COMPRESS;
566
567 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
568 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
569 db->db.db_object, db->db_level, db->db_blkid);
570
571 dbuf_add_ref(db, NULL);
572
573 (void) arc_read(zio, db->db_objset->os_spa, db->db_blkptr,
574 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
575 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
576 &aflags, &zb);
577 if (aflags & ARC_FLAG_CACHED)
578 *flags |= DB_RF_CACHED;
579}
580
581int
582dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
583{
584 int err = 0;
585 boolean_t havepzio = (zio != NULL);
586 boolean_t prefetch;
587 dnode_t *dn;
588
589 /*
590 * We don't have to hold the mutex to check db_state because it
591 * can't be freed while we have a hold on the buffer.
592 */
593 ASSERT(!refcount_is_zero(&db->db_holds));
594
595 if (db->db_state == DB_NOFILL)
596 return (SET_ERROR(EIO));
597
598 DB_DNODE_ENTER(db);
599 dn = DB_DNODE(db);
600 if ((flags & DB_RF_HAVESTRUCT) == 0)
601 rw_enter(&dn->dn_struct_rwlock, RW_READER);
602
603 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
604 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL &&
605 DBUF_IS_CACHEABLE(db);
606
607 mutex_enter(&db->db_mtx);
608 if (db->db_state == DB_CACHED) {
609 mutex_exit(&db->db_mtx);
610 if (prefetch)
611 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
612 db->db.db_size, TRUE);
613 if ((flags & DB_RF_HAVESTRUCT) == 0)
614 rw_exit(&dn->dn_struct_rwlock);
615 DB_DNODE_EXIT(db);
616 } else if (db->db_state == DB_UNCACHED) {
617 spa_t *spa = dn->dn_objset->os_spa;
618
619 if (zio == NULL)
620 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
621 dbuf_read_impl(db, zio, &flags);
622
623 /* dbuf_read_impl has dropped db_mtx for us */
624
625 if (prefetch)
626 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
627 db->db.db_size, flags & DB_RF_CACHED);
628
629 if ((flags & DB_RF_HAVESTRUCT) == 0)
630 rw_exit(&dn->dn_struct_rwlock);
631 DB_DNODE_EXIT(db);
632
633 if (!havepzio)
634 err = zio_wait(zio);
635 } else {
636 /*
637 * Another reader came in while the dbuf was in flight
638 * between UNCACHED and CACHED. Either a writer will finish
639 * writing the buffer (sending the dbuf to CACHED) or the
640 * first reader's request will reach the read_done callback
641 * and send the dbuf to CACHED. Otherwise, a failure
642 * occurred and the dbuf went to UNCACHED.
643 */
644 mutex_exit(&db->db_mtx);
645 if (prefetch)
646 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
647 db->db.db_size, TRUE);
648 if ((flags & DB_RF_HAVESTRUCT) == 0)
649 rw_exit(&dn->dn_struct_rwlock);
650 DB_DNODE_EXIT(db);
651
652 /* Skip the wait per the caller's request. */
653 mutex_enter(&db->db_mtx);
654 if ((flags & DB_RF_NEVERWAIT) == 0) {
655 while (db->db_state == DB_READ ||
656 db->db_state == DB_FILL) {
657 ASSERT(db->db_state == DB_READ ||
658 (flags & DB_RF_HAVESTRUCT) == 0);
659 DTRACE_PROBE2(blocked__read, dmu_buf_impl_t *,
660 db, zio_t *, zio);
661 cv_wait(&db->db_changed, &db->db_mtx);
662 }
663 if (db->db_state == DB_UNCACHED)
664 err = SET_ERROR(EIO);
665 }
666 mutex_exit(&db->db_mtx);
667 }
668
669 ASSERT(err || havepzio || db->db_state == DB_CACHED);
670 return (err);
671}
672
673static void
674dbuf_noread(dmu_buf_impl_t *db)
675{
676 ASSERT(!refcount_is_zero(&db->db_holds));
677 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
678 mutex_enter(&db->db_mtx);
679 while (db->db_state == DB_READ || db->db_state == DB_FILL)
680 cv_wait(&db->db_changed, &db->db_mtx);
681 if (db->db_state == DB_UNCACHED) {
682 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
683 spa_t *spa = db->db_objset->os_spa;
684
685 ASSERT(db->db_buf == NULL);
686 ASSERT(db->db.db_data == NULL);
687 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type));
688 db->db_state = DB_FILL;
689 } else if (db->db_state == DB_NOFILL) {
690 dbuf_set_data(db, NULL);
691 } else {
692 ASSERT3U(db->db_state, ==, DB_CACHED);
693 }
694 mutex_exit(&db->db_mtx);
695}
696
697/*
698 * This is our just-in-time copy function. It makes a copy of
699 * buffers, that have been modified in a previous transaction
700 * group, before we modify them in the current active group.
701 *
702 * This function is used in two places: when we are dirtying a
703 * buffer for the first time in a txg, and when we are freeing
704 * a range in a dnode that includes this buffer.
705 *
706 * Note that when we are called from dbuf_free_range() we do
707 * not put a hold on the buffer, we just traverse the active
708 * dbuf list for the dnode.
709 */
710static void
711dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
712{
713 dbuf_dirty_record_t *dr = db->db_last_dirty;
714
715 ASSERT(MUTEX_HELD(&db->db_mtx));
716 ASSERT(db->db.db_data != NULL);
717 ASSERT(db->db_level == 0);
718 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT);
719
720 if (dr == NULL ||
721 (dr->dt.dl.dr_data !=
722 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf)))
723 return;
724
725 /*
726 * If the last dirty record for this dbuf has not yet synced
727 * and its referencing the dbuf data, either:
728 * reset the reference to point to a new copy,
729 * or (if there a no active holders)
730 * just null out the current db_data pointer.
731 */
732 ASSERT(dr->dr_txg >= txg - 2);
733 if (db->db_blkid == DMU_BONUS_BLKID) {
734 /* Note that the data bufs here are zio_bufs */
735 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
736 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
737 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
738 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
739 int size = db->db.db_size;
740 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
741 spa_t *spa = db->db_objset->os_spa;
742
743 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type);
744 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
745 } else {
746 dbuf_set_data(db, NULL);
747 }
748}
749
750void
751dbuf_unoverride(dbuf_dirty_record_t *dr)
752{
753 dmu_buf_impl_t *db = dr->dr_dbuf;
754 blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
755 uint64_t txg = dr->dr_txg;
756
757 ASSERT(MUTEX_HELD(&db->db_mtx));
758 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
759 ASSERT(db->db_level == 0);
760
761 if (db->db_blkid == DMU_BONUS_BLKID ||
762 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
763 return;
764
765 ASSERT(db->db_data_pending != dr);
766
767 /* free this block */
768 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite)
769 zio_free(db->db_objset->os_spa, txg, bp);
770
771 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
772 dr->dt.dl.dr_nopwrite = B_FALSE;
773
774 /*
775 * Release the already-written buffer, so we leave it in
776 * a consistent dirty state. Note that all callers are
777 * modifying the buffer, so they will immediately do
778 * another (redundant) arc_release(). Therefore, leave
779 * the buf thawed to save the effort of freezing &
780 * immediately re-thawing it.
781 */
782 arc_release(dr->dt.dl.dr_data, db);
783}
784
785/*
786 * Evict (if its unreferenced) or clear (if its referenced) any level-0
787 * data blocks in the free range, so that any future readers will find
788 * empty blocks.
789 *
790 * This is a no-op if the dataset is in the middle of an incremental
791 * receive; see comment below for details.
792 */
793void
794dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid,
795 dmu_tx_t *tx)
796{
797 dmu_buf_impl_t *db, *db_next, db_search;
798 uint64_t txg = tx->tx_txg;
799 avl_index_t where;
800
801 if (end_blkid > dn->dn_maxblkid && (end_blkid != DMU_SPILL_BLKID))
802 end_blkid = dn->dn_maxblkid;
803 dprintf_dnode(dn, "start=%llu end=%llu\n", start_blkid, end_blkid);
804
805 db_search.db_level = 0;
806 db_search.db_blkid = start_blkid;
807 db_search.db_state = DB_SEARCH;
808
809 mutex_enter(&dn->dn_dbufs_mtx);
810 if (start_blkid >= dn->dn_unlisted_l0_blkid) {
811 /* There can't be any dbufs in this range; no need to search. */
812#ifdef DEBUG
813 db = avl_find(&dn->dn_dbufs, &db_search, &where);
814 ASSERT3P(db, ==, NULL);
815 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER);
816 ASSERT(db == NULL || db->db_level > 0);
817#endif
818 mutex_exit(&dn->dn_dbufs_mtx);
819 return;
820 } else if (dmu_objset_is_receiving(dn->dn_objset)) {
821 /*
822 * If we are receiving, we expect there to be no dbufs in
823 * the range to be freed, because receive modifies each
824 * block at most once, and in offset order. If this is
825 * not the case, it can lead to performance problems,
826 * so note that we unexpectedly took the slow path.
827 */
828 atomic_inc_64(&zfs_free_range_recv_miss);
829 }
830
831 db = avl_find(&dn->dn_dbufs, &db_search, &where);
832 ASSERT3P(db, ==, NULL);
833 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER);
834
835 for (; db != NULL; db = db_next) {
836 db_next = AVL_NEXT(&dn->dn_dbufs, db);
837 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
838
839 if (db->db_level != 0 || db->db_blkid > end_blkid) {
840 break;
841 }
842 ASSERT3U(db->db_blkid, >=, start_blkid);
843
844 /* found a level 0 buffer in the range */
845 mutex_enter(&db->db_mtx);
846 if (dbuf_undirty(db, tx)) {
847 /* mutex has been dropped and dbuf destroyed */
848 continue;
849 }
850
851 if (db->db_state == DB_UNCACHED ||
852 db->db_state == DB_NOFILL ||
853 db->db_state == DB_EVICTING) {
854 ASSERT(db->db.db_data == NULL);
855 mutex_exit(&db->db_mtx);
856 continue;
857 }
858 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
859 /* will be handled in dbuf_read_done or dbuf_rele */
860 db->db_freed_in_flight = TRUE;
861 mutex_exit(&db->db_mtx);
862 continue;
863 }
864 if (refcount_count(&db->db_holds) == 0) {
865 ASSERT(db->db_buf);
866 dbuf_clear(db);
867 continue;
868 }
869 /* The dbuf is referenced */
870
871 if (db->db_last_dirty != NULL) {
872 dbuf_dirty_record_t *dr = db->db_last_dirty;
873
874 if (dr->dr_txg == txg) {
875 /*
876 * This buffer is "in-use", re-adjust the file
877 * size to reflect that this buffer may
878 * contain new data when we sync.
879 */
880 if (db->db_blkid != DMU_SPILL_BLKID &&
881 db->db_blkid > dn->dn_maxblkid)
882 dn->dn_maxblkid = db->db_blkid;
883 dbuf_unoverride(dr);
884 } else {
885 /*
886 * This dbuf is not dirty in the open context.
887 * Either uncache it (if its not referenced in
888 * the open context) or reset its contents to
889 * empty.
890 */
891 dbuf_fix_old_data(db, txg);
892 }
893 }
894 /* clear the contents if its cached */
895 if (db->db_state == DB_CACHED) {
896 ASSERT(db->db.db_data != NULL);
897 arc_release(db->db_buf, db);
898 bzero(db->db.db_data, db->db.db_size);
899 arc_buf_freeze(db->db_buf);
900 }
901
902 mutex_exit(&db->db_mtx);
903 }
904 mutex_exit(&dn->dn_dbufs_mtx);
905}
906
907static int
908dbuf_block_freeable(dmu_buf_impl_t *db)
909{
910 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
911 uint64_t birth_txg = 0;
912
913 /*
914 * We don't need any locking to protect db_blkptr:
915 * If it's syncing, then db_last_dirty will be set
916 * so we'll ignore db_blkptr.
917 *
918 * This logic ensures that only block births for
919 * filled blocks are considered.
920 */
921 ASSERT(MUTEX_HELD(&db->db_mtx));
922 if (db->db_last_dirty && (db->db_blkptr == NULL ||
923 !BP_IS_HOLE(db->db_blkptr))) {
924 birth_txg = db->db_last_dirty->dr_txg;
925 } else if (db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr)) {
926 birth_txg = db->db_blkptr->blk_birth;
927 }
928
929 /*
930 * If this block don't exist or is in a snapshot, it can't be freed.
931 * Don't pass the bp to dsl_dataset_block_freeable() since we
932 * are holding the db_mtx lock and might deadlock if we are
933 * prefetching a dedup-ed block.
934 */
935 if (birth_txg != 0)
936 return (ds == NULL ||
937 dsl_dataset_block_freeable(ds, NULL, birth_txg));
938 else
939 return (B_FALSE);
940}
941
942void
943dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
944{
945 arc_buf_t *buf, *obuf;
946 int osize = db->db.db_size;
947 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
948 dnode_t *dn;
949
950 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
951
952 DB_DNODE_ENTER(db);
953 dn = DB_DNODE(db);
954
955 /* XXX does *this* func really need the lock? */
956 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
957
958 /*
959 * This call to dmu_buf_will_dirty() with the dn_struct_rwlock held
960 * is OK, because there can be no other references to the db
961 * when we are changing its size, so no concurrent DB_FILL can
962 * be happening.
963 */
964 /*
965 * XXX we should be doing a dbuf_read, checking the return
966 * value and returning that up to our callers
967 */
968 dmu_buf_will_dirty(&db->db, tx);
969
970 /* create the data buffer for the new block */
971 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type);
972
973 /* copy old block data to the new block */
974 obuf = db->db_buf;
975 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
976 /* zero the remainder */
977 if (size > osize)
978 bzero((uint8_t *)buf->b_data + osize, size - osize);
979
980 mutex_enter(&db->db_mtx);
981 dbuf_set_data(db, buf);
982 VERIFY(arc_buf_remove_ref(obuf, db));
983 db->db.db_size = size;
984
985 if (db->db_level == 0) {
986 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
987 db->db_last_dirty->dt.dl.dr_data = buf;
988 }
989 mutex_exit(&db->db_mtx);
990
991 dnode_willuse_space(dn, size-osize, tx);
992 DB_DNODE_EXIT(db);
993}
994
995void
996dbuf_release_bp(dmu_buf_impl_t *db)
997{
998 objset_t *os = db->db_objset;
999
1000 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
1001 ASSERT(arc_released(os->os_phys_buf) ||
1002 list_link_active(&os->os_dsl_dataset->ds_synced_link));
1003 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf));
1004
1005 (void) arc_release(db->db_buf, db);
1006}
1007
1008dbuf_dirty_record_t *
1009dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1010{
1011 dnode_t *dn;
1012 objset_t *os;
1013 dbuf_dirty_record_t **drp, *dr;
1014 int drop_struct_lock = FALSE;
1015 boolean_t do_free_accounting = B_FALSE;
1016 int txgoff = tx->tx_txg & TXG_MASK;
1017
1018 ASSERT(tx->tx_txg != 0);
1019 ASSERT(!refcount_is_zero(&db->db_holds));
1020 DMU_TX_DIRTY_BUF(tx, db);
1021
1022 DB_DNODE_ENTER(db);
1023 dn = DB_DNODE(db);
1024 /*
1025 * Shouldn't dirty a regular buffer in syncing context. Private
1026 * objects may be dirtied in syncing context, but only if they
1027 * were already pre-dirtied in open context.
1028 */
1029 ASSERT(!dmu_tx_is_syncing(tx) ||
1030 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
1031 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1032 dn->dn_objset->os_dsl_dataset == NULL);
1033 /*
1034 * We make this assert for private objects as well, but after we
1035 * check if we're already dirty. They are allowed to re-dirty
1036 * in syncing context.
1037 */
1038 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1039 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1040 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1041
1042 mutex_enter(&db->db_mtx);
1043 /*
1044 * XXX make this true for indirects too? The problem is that
1045 * transactions created with dmu_tx_create_assigned() from
1046 * syncing context don't bother holding ahead.
1047 */
1048 ASSERT(db->db_level != 0 ||
1049 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
1050 db->db_state == DB_NOFILL);
1051
1052 mutex_enter(&dn->dn_mtx);
1053 /*
1054 * Don't set dirtyctx to SYNC if we're just modifying this as we
1055 * initialize the objset.
1056 */
1057 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
1058 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
1059 dn->dn_dirtyctx =
1060 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
1061 ASSERT(dn->dn_dirtyctx_firstset == NULL);
1062 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
1063 }
1064 mutex_exit(&dn->dn_mtx);
1065
1066 if (db->db_blkid == DMU_SPILL_BLKID)
1067 dn->dn_have_spill = B_TRUE;
1068
1069 /*
1070 * If this buffer is already dirty, we're done.
1071 */
1072 drp = &db->db_last_dirty;
1073 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
1074 db->db.db_object == DMU_META_DNODE_OBJECT);
1075 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
1076 drp = &dr->dr_next;
1077 if (dr && dr->dr_txg == tx->tx_txg) {
1078 DB_DNODE_EXIT(db);
1079
1080 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
1081 /*
1082 * If this buffer has already been written out,
1083 * we now need to reset its state.
1084 */
1085 dbuf_unoverride(dr);
1086 if (db->db.db_object != DMU_META_DNODE_OBJECT &&
1087 db->db_state != DB_NOFILL)
1088 arc_buf_thaw(db->db_buf);
1089 }
1090 mutex_exit(&db->db_mtx);
1091 return (dr);
1092 }
1093
1094 /*
1095 * Only valid if not already dirty.
1096 */
1097 ASSERT(dn->dn_object == 0 ||
1098 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1099 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1100
1101 ASSERT3U(dn->dn_nlevels, >, db->db_level);
1102 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
1103 dn->dn_phys->dn_nlevels > db->db_level ||
1104 dn->dn_next_nlevels[txgoff] > db->db_level ||
1105 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
1106 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
1107
1108 /*
1109 * We should only be dirtying in syncing context if it's the
1110 * mos or we're initializing the os or it's a special object.
1111 * However, we are allowed to dirty in syncing context provided
1112 * we already dirtied it in open context. Hence we must make
1113 * this assertion only if we're not already dirty.
1114 */
1115 os = dn->dn_objset;
1116 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1117 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
1118 ASSERT(db->db.db_size != 0);
1119
1120 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1121
1122 if (db->db_blkid != DMU_BONUS_BLKID) {
1123 /*
1124 * Update the accounting.
1125 * Note: we delay "free accounting" until after we drop
1126 * the db_mtx. This keeps us from grabbing other locks
1127 * (and possibly deadlocking) in bp_get_dsize() while
1128 * also holding the db_mtx.
1129 */
1130 dnode_willuse_space(dn, db->db.db_size, tx);
1131 do_free_accounting = dbuf_block_freeable(db);
1132 }
1133
1134 /*
1135 * If this buffer is dirty in an old transaction group we need
1136 * to make a copy of it so that the changes we make in this
1137 * transaction group won't leak out when we sync the older txg.
1138 */
1139 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP);
1140 if (db->db_level == 0) {
1141 void *data_old = db->db_buf;
1142
1143 if (db->db_state != DB_NOFILL) {
1144 if (db->db_blkid == DMU_BONUS_BLKID) {
1145 dbuf_fix_old_data(db, tx->tx_txg);
1146 data_old = db->db.db_data;
1147 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1148 /*
1149 * Release the data buffer from the cache so
1150 * that we can modify it without impacting
1151 * possible other users of this cached data
1152 * block. Note that indirect blocks and
1153 * private objects are not released until the
1154 * syncing state (since they are only modified
1155 * then).
1156 */
1157 arc_release(db->db_buf, db);
1158 dbuf_fix_old_data(db, tx->tx_txg);
1159 data_old = db->db_buf;
1160 }
1161 ASSERT(data_old != NULL);
1162 }
1163 dr->dt.dl.dr_data = data_old;
1164 } else {
1165 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1166 list_create(&dr->dt.di.dr_children,
1167 sizeof (dbuf_dirty_record_t),
1168 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1169 }
1170 if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL)
1171 dr->dr_accounted = db->db.db_size;
1172 dr->dr_dbuf = db;
1173 dr->dr_txg = tx->tx_txg;
1174 dr->dr_next = *drp;
1175 *drp = dr;
1176
1177 /*
1178 * We could have been freed_in_flight between the dbuf_noread
1179 * and dbuf_dirty. We win, as though the dbuf_noread() had
1180 * happened after the free.
1181 */
1182 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1183 db->db_blkid != DMU_SPILL_BLKID) {
1184 mutex_enter(&dn->dn_mtx);
1185 if (dn->dn_free_ranges[txgoff] != NULL) {
1186 range_tree_clear(dn->dn_free_ranges[txgoff],
1187 db->db_blkid, 1);
1188 }
1189 mutex_exit(&dn->dn_mtx);
1190 db->db_freed_in_flight = FALSE;
1191 }
1192
1193 /*
1194 * This buffer is now part of this txg
1195 */
1196 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1197 db->db_dirtycnt += 1;
1198 ASSERT3U(db->db_dirtycnt, <=, 3);
1199
1200 mutex_exit(&db->db_mtx);
1201
1202 if (db->db_blkid == DMU_BONUS_BLKID ||
1203 db->db_blkid == DMU_SPILL_BLKID) {
1204 mutex_enter(&dn->dn_mtx);
1205 ASSERT(!list_link_active(&dr->dr_dirty_node));
1206 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1207 mutex_exit(&dn->dn_mtx);
1208 dnode_setdirty(dn, tx);
1209 DB_DNODE_EXIT(db);
1210 return (dr);
1211 } else if (do_free_accounting) {
1212 blkptr_t *bp = db->db_blkptr;
1213 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1214 bp_get_dsize(os->os_spa, bp) : db->db.db_size;
1215 /*
1216 * This is only a guess -- if the dbuf is dirty
1217 * in a previous txg, we don't know how much
1218 * space it will use on disk yet. We should
1219 * really have the struct_rwlock to access
1220 * db_blkptr, but since this is just a guess,
1221 * it's OK if we get an odd answer.
1222 */
1223 ddt_prefetch(os->os_spa, bp);
1224 dnode_willuse_space(dn, -willfree, tx);
1225 }
1226
1227 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1228 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1229 drop_struct_lock = TRUE;
1230 }
1231
1232 if (db->db_level == 0) {
1233 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1234 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1235 }
1236
1237 if (db->db_level+1 < dn->dn_nlevels) {
1238 dmu_buf_impl_t *parent = db->db_parent;
1239 dbuf_dirty_record_t *di;
1240 int parent_held = FALSE;
1241
1242 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1243 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1244
1245 parent = dbuf_hold_level(dn, db->db_level+1,
1246 db->db_blkid >> epbs, FTAG);
1247 ASSERT(parent != NULL);
1248 parent_held = TRUE;
1249 }
1250 if (drop_struct_lock)
1251 rw_exit(&dn->dn_struct_rwlock);
1252 ASSERT3U(db->db_level+1, ==, parent->db_level);
1253 di = dbuf_dirty(parent, tx);
1254 if (parent_held)
1255 dbuf_rele(parent, FTAG);
1256
1257 mutex_enter(&db->db_mtx);
1258 /*
1259 * Since we've dropped the mutex, it's possible that
1260 * dbuf_undirty() might have changed this out from under us.
1261 */
1262 if (db->db_last_dirty == dr ||
1263 dn->dn_object == DMU_META_DNODE_OBJECT) {
1264 mutex_enter(&di->dt.di.dr_mtx);
1265 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1266 ASSERT(!list_link_active(&dr->dr_dirty_node));
1267 list_insert_tail(&di->dt.di.dr_children, dr);
1268 mutex_exit(&di->dt.di.dr_mtx);
1269 dr->dr_parent = di;
1270 }
1271 mutex_exit(&db->db_mtx);
1272 } else {
1273 ASSERT(db->db_level+1 == dn->dn_nlevels);
1274 ASSERT(db->db_blkid < dn->dn_nblkptr);
1275 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf);
1276 mutex_enter(&dn->dn_mtx);
1277 ASSERT(!list_link_active(&dr->dr_dirty_node));
1278 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1279 mutex_exit(&dn->dn_mtx);
1280 if (drop_struct_lock)
1281 rw_exit(&dn->dn_struct_rwlock);
1282 }
1283
1284 dnode_setdirty(dn, tx);
1285 DB_DNODE_EXIT(db);
1286 return (dr);
1287}
1288
1289/*
1290 * Undirty a buffer in the transaction group referenced by the given
1291 * transaction. Return whether this evicted the dbuf.
1292 */
1293static boolean_t
1294dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1295{
1296 dnode_t *dn;
1297 uint64_t txg = tx->tx_txg;
1298 dbuf_dirty_record_t *dr, **drp;
1299
1300 ASSERT(txg != 0);
| 25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
26 * Copyright (c) 2013, Joyent, Inc. All rights reserved.
27 */
28
29#include <sys/zfs_context.h>
30#include <sys/dmu.h>
31#include <sys/dmu_send.h>
32#include <sys/dmu_impl.h>
33#include <sys/dbuf.h>
34#include <sys/dmu_objset.h>
35#include <sys/dsl_dataset.h>
36#include <sys/dsl_dir.h>
37#include <sys/dmu_tx.h>
38#include <sys/spa.h>
39#include <sys/zio.h>
40#include <sys/dmu_zfetch.h>
41#include <sys/sa.h>
42#include <sys/sa_impl.h>
43#include <sys/zfeature.h>
44#include <sys/blkptr.h>
45#include <sys/range_tree.h>
46
47/*
48 * Number of times that zfs_free_range() took the slow path while doing
49 * a zfs receive. A nonzero value indicates a potential performance problem.
50 */
51uint64_t zfs_free_range_recv_miss;
52
53static void dbuf_destroy(dmu_buf_impl_t *db);
54static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
55static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
56
57/*
58 * Global data structures and functions for the dbuf cache.
59 */
60static kmem_cache_t *dbuf_cache;
61
62/* ARGSUSED */
63static int
64dbuf_cons(void *vdb, void *unused, int kmflag)
65{
66 dmu_buf_impl_t *db = vdb;
67 bzero(db, sizeof (dmu_buf_impl_t));
68
69 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
70 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
71 refcount_create(&db->db_holds);
72
73 return (0);
74}
75
76/* ARGSUSED */
77static void
78dbuf_dest(void *vdb, void *unused)
79{
80 dmu_buf_impl_t *db = vdb;
81 mutex_destroy(&db->db_mtx);
82 cv_destroy(&db->db_changed);
83 refcount_destroy(&db->db_holds);
84}
85
86/*
87 * dbuf hash table routines
88 */
89static dbuf_hash_table_t dbuf_hash_table;
90
91static uint64_t dbuf_hash_count;
92
93static uint64_t
94dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
95{
96 uintptr_t osv = (uintptr_t)os;
97 uint64_t crc = -1ULL;
98
99 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
100 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
101 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
102 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
103 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
104 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
105 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
106
107 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
108
109 return (crc);
110}
111
112#define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
113
114#define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
115 ((dbuf)->db.db_object == (obj) && \
116 (dbuf)->db_objset == (os) && \
117 (dbuf)->db_level == (level) && \
118 (dbuf)->db_blkid == (blkid))
119
120dmu_buf_impl_t *
121dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
122{
123 dbuf_hash_table_t *h = &dbuf_hash_table;
124 objset_t *os = dn->dn_objset;
125 uint64_t obj = dn->dn_object;
126 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
127 uint64_t idx = hv & h->hash_table_mask;
128 dmu_buf_impl_t *db;
129
130 mutex_enter(DBUF_HASH_MUTEX(h, idx));
131 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
132 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
133 mutex_enter(&db->db_mtx);
134 if (db->db_state != DB_EVICTING) {
135 mutex_exit(DBUF_HASH_MUTEX(h, idx));
136 return (db);
137 }
138 mutex_exit(&db->db_mtx);
139 }
140 }
141 mutex_exit(DBUF_HASH_MUTEX(h, idx));
142 return (NULL);
143}
144
145/*
146 * Insert an entry into the hash table. If there is already an element
147 * equal to elem in the hash table, then the already existing element
148 * will be returned and the new element will not be inserted.
149 * Otherwise returns NULL.
150 */
151static dmu_buf_impl_t *
152dbuf_hash_insert(dmu_buf_impl_t *db)
153{
154 dbuf_hash_table_t *h = &dbuf_hash_table;
155 objset_t *os = db->db_objset;
156 uint64_t obj = db->db.db_object;
157 int level = db->db_level;
158 uint64_t blkid = db->db_blkid;
159 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
160 uint64_t idx = hv & h->hash_table_mask;
161 dmu_buf_impl_t *dbf;
162
163 mutex_enter(DBUF_HASH_MUTEX(h, idx));
164 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
165 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
166 mutex_enter(&dbf->db_mtx);
167 if (dbf->db_state != DB_EVICTING) {
168 mutex_exit(DBUF_HASH_MUTEX(h, idx));
169 return (dbf);
170 }
171 mutex_exit(&dbf->db_mtx);
172 }
173 }
174
175 mutex_enter(&db->db_mtx);
176 db->db_hash_next = h->hash_table[idx];
177 h->hash_table[idx] = db;
178 mutex_exit(DBUF_HASH_MUTEX(h, idx));
179 atomic_inc_64(&dbuf_hash_count);
180
181 return (NULL);
182}
183
184/*
185 * Remove an entry from the hash table. It must be in the EVICTING state.
186 */
187static void
188dbuf_hash_remove(dmu_buf_impl_t *db)
189{
190 dbuf_hash_table_t *h = &dbuf_hash_table;
191 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object,
192 db->db_level, db->db_blkid);
193 uint64_t idx = hv & h->hash_table_mask;
194 dmu_buf_impl_t *dbf, **dbp;
195
196 /*
197 * We musn't hold db_mtx to maintain lock ordering:
198 * DBUF_HASH_MUTEX > db_mtx.
199 */
200 ASSERT(refcount_is_zero(&db->db_holds));
201 ASSERT(db->db_state == DB_EVICTING);
202 ASSERT(!MUTEX_HELD(&db->db_mtx));
203
204 mutex_enter(DBUF_HASH_MUTEX(h, idx));
205 dbp = &h->hash_table[idx];
206 while ((dbf = *dbp) != db) {
207 dbp = &dbf->db_hash_next;
208 ASSERT(dbf != NULL);
209 }
210 *dbp = db->db_hash_next;
211 db->db_hash_next = NULL;
212 mutex_exit(DBUF_HASH_MUTEX(h, idx));
213 atomic_dec_64(&dbuf_hash_count);
214}
215
216static arc_evict_func_t dbuf_do_evict;
217
218static void
219dbuf_evict_user(dmu_buf_impl_t *db)
220{
221 ASSERT(MUTEX_HELD(&db->db_mtx));
222
223 if (db->db_level != 0 || db->db_evict_func == NULL)
224 return;
225
226 db->db_evict_func(&db->db, db->db_user_ptr);
227 db->db_user_ptr = NULL;
228 db->db_evict_func = NULL;
229}
230
231boolean_t
232dbuf_is_metadata(dmu_buf_impl_t *db)
233{
234 if (db->db_level > 0) {
235 return (B_TRUE);
236 } else {
237 boolean_t is_metadata;
238
239 DB_DNODE_ENTER(db);
240 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type);
241 DB_DNODE_EXIT(db);
242
243 return (is_metadata);
244 }
245}
246
247void
248dbuf_evict(dmu_buf_impl_t *db)
249{
250 ASSERT(MUTEX_HELD(&db->db_mtx));
251 ASSERT(db->db_buf == NULL);
252 ASSERT(db->db_data_pending == NULL);
253
254 dbuf_clear(db);
255 dbuf_destroy(db);
256}
257
258void
259dbuf_init(void)
260{
261 uint64_t hsize = 1ULL << 16;
262 dbuf_hash_table_t *h = &dbuf_hash_table;
263 int i;
264
265 /*
266 * The hash table is big enough to fill all of physical memory
267 * with an average 4K block size. The table will take up
268 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
269 */
270 while (hsize * 4096 < (uint64_t)physmem * PAGESIZE)
271 hsize <<= 1;
272
273retry:
274 h->hash_table_mask = hsize - 1;
275 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
276 if (h->hash_table == NULL) {
277 /* XXX - we should really return an error instead of assert */
278 ASSERT(hsize > (1ULL << 10));
279 hsize >>= 1;
280 goto retry;
281 }
282
283 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
284 sizeof (dmu_buf_impl_t),
285 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
286
287 for (i = 0; i < DBUF_MUTEXES; i++)
288 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
289}
290
291void
292dbuf_fini(void)
293{
294 dbuf_hash_table_t *h = &dbuf_hash_table;
295 int i;
296
297 for (i = 0; i < DBUF_MUTEXES; i++)
298 mutex_destroy(&h->hash_mutexes[i]);
299 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
300 kmem_cache_destroy(dbuf_cache);
301}
302
303/*
304 * Other stuff.
305 */
306
307#ifdef ZFS_DEBUG
308static void
309dbuf_verify(dmu_buf_impl_t *db)
310{
311 dnode_t *dn;
312 dbuf_dirty_record_t *dr;
313
314 ASSERT(MUTEX_HELD(&db->db_mtx));
315
316 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
317 return;
318
319 ASSERT(db->db_objset != NULL);
320 DB_DNODE_ENTER(db);
321 dn = DB_DNODE(db);
322 if (dn == NULL) {
323 ASSERT(db->db_parent == NULL);
324 ASSERT(db->db_blkptr == NULL);
325 } else {
326 ASSERT3U(db->db.db_object, ==, dn->dn_object);
327 ASSERT3P(db->db_objset, ==, dn->dn_objset);
328 ASSERT3U(db->db_level, <, dn->dn_nlevels);
329 ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
330 db->db_blkid == DMU_SPILL_BLKID ||
331 !avl_is_empty(&dn->dn_dbufs));
332 }
333 if (db->db_blkid == DMU_BONUS_BLKID) {
334 ASSERT(dn != NULL);
335 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
336 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID);
337 } else if (db->db_blkid == DMU_SPILL_BLKID) {
338 ASSERT(dn != NULL);
339 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
340 ASSERT0(db->db.db_offset);
341 } else {
342 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
343 }
344
345 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
346 ASSERT(dr->dr_dbuf == db);
347
348 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
349 ASSERT(dr->dr_dbuf == db);
350
351 /*
352 * We can't assert that db_size matches dn_datablksz because it
353 * can be momentarily different when another thread is doing
354 * dnode_set_blksz().
355 */
356 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
357 dr = db->db_data_pending;
358 /*
359 * It should only be modified in syncing context, so
360 * make sure we only have one copy of the data.
361 */
362 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
363 }
364
365 /* verify db->db_blkptr */
366 if (db->db_blkptr) {
367 if (db->db_parent == dn->dn_dbuf) {
368 /* db is pointed to by the dnode */
369 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
370 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
371 ASSERT(db->db_parent == NULL);
372 else
373 ASSERT(db->db_parent != NULL);
374 if (db->db_blkid != DMU_SPILL_BLKID)
375 ASSERT3P(db->db_blkptr, ==,
376 &dn->dn_phys->dn_blkptr[db->db_blkid]);
377 } else {
378 /* db is pointed to by an indirect block */
379 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT;
380 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
381 ASSERT3U(db->db_parent->db.db_object, ==,
382 db->db.db_object);
383 /*
384 * dnode_grow_indblksz() can make this fail if we don't
385 * have the struct_rwlock. XXX indblksz no longer
386 * grows. safe to do this now?
387 */
388 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
389 ASSERT3P(db->db_blkptr, ==,
390 ((blkptr_t *)db->db_parent->db.db_data +
391 db->db_blkid % epb));
392 }
393 }
394 }
395 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
396 (db->db_buf == NULL || db->db_buf->b_data) &&
397 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID &&
398 db->db_state != DB_FILL && !dn->dn_free_txg) {
399 /*
400 * If the blkptr isn't set but they have nonzero data,
401 * it had better be dirty, otherwise we'll lose that
402 * data when we evict this buffer.
403 */
404 if (db->db_dirtycnt == 0) {
405 uint64_t *buf = db->db.db_data;
406 int i;
407
408 for (i = 0; i < db->db.db_size >> 3; i++) {
409 ASSERT(buf[i] == 0);
410 }
411 }
412 }
413 DB_DNODE_EXIT(db);
414}
415#endif
416
417static void
418dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
419{
420 ASSERT(MUTEX_HELD(&db->db_mtx));
421 db->db_buf = buf;
422 if (buf != NULL) {
423 ASSERT(buf->b_data != NULL);
424 db->db.db_data = buf->b_data;
425 if (!arc_released(buf))
426 arc_set_callback(buf, dbuf_do_evict, db);
427 } else {
428 dbuf_evict_user(db);
429 db->db.db_data = NULL;
430 if (db->db_state != DB_NOFILL)
431 db->db_state = DB_UNCACHED;
432 }
433}
434
435/*
436 * Loan out an arc_buf for read. Return the loaned arc_buf.
437 */
438arc_buf_t *
439dbuf_loan_arcbuf(dmu_buf_impl_t *db)
440{
441 arc_buf_t *abuf;
442
443 mutex_enter(&db->db_mtx);
444 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
445 int blksz = db->db.db_size;
446 spa_t *spa = db->db_objset->os_spa;
447
448 mutex_exit(&db->db_mtx);
449 abuf = arc_loan_buf(spa, blksz);
450 bcopy(db->db.db_data, abuf->b_data, blksz);
451 } else {
452 abuf = db->db_buf;
453 arc_loan_inuse_buf(abuf, db);
454 dbuf_set_data(db, NULL);
455 mutex_exit(&db->db_mtx);
456 }
457 return (abuf);
458}
459
460uint64_t
461dbuf_whichblock(dnode_t *dn, uint64_t offset)
462{
463 if (dn->dn_datablkshift) {
464 return (offset >> dn->dn_datablkshift);
465 } else {
466 ASSERT3U(offset, <, dn->dn_datablksz);
467 return (0);
468 }
469}
470
471static void
472dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
473{
474 dmu_buf_impl_t *db = vdb;
475
476 mutex_enter(&db->db_mtx);
477 ASSERT3U(db->db_state, ==, DB_READ);
478 /*
479 * All reads are synchronous, so we must have a hold on the dbuf
480 */
481 ASSERT(refcount_count(&db->db_holds) > 0);
482 ASSERT(db->db_buf == NULL);
483 ASSERT(db->db.db_data == NULL);
484 if (db->db_level == 0 && db->db_freed_in_flight) {
485 /* we were freed in flight; disregard any error */
486 arc_release(buf, db);
487 bzero(buf->b_data, db->db.db_size);
488 arc_buf_freeze(buf);
489 db->db_freed_in_flight = FALSE;
490 dbuf_set_data(db, buf);
491 db->db_state = DB_CACHED;
492 } else if (zio == NULL || zio->io_error == 0) {
493 dbuf_set_data(db, buf);
494 db->db_state = DB_CACHED;
495 } else {
496 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
497 ASSERT3P(db->db_buf, ==, NULL);
498 VERIFY(arc_buf_remove_ref(buf, db));
499 db->db_state = DB_UNCACHED;
500 }
501 cv_broadcast(&db->db_changed);
502 dbuf_rele_and_unlock(db, NULL);
503}
504
505static void
506dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
507{
508 dnode_t *dn;
509 zbookmark_phys_t zb;
510 arc_flags_t aflags = ARC_FLAG_NOWAIT;
511
512 DB_DNODE_ENTER(db);
513 dn = DB_DNODE(db);
514 ASSERT(!refcount_is_zero(&db->db_holds));
515 /* We need the struct_rwlock to prevent db_blkptr from changing. */
516 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
517 ASSERT(MUTEX_HELD(&db->db_mtx));
518 ASSERT(db->db_state == DB_UNCACHED);
519 ASSERT(db->db_buf == NULL);
520
521 if (db->db_blkid == DMU_BONUS_BLKID) {
522 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
523
524 ASSERT3U(bonuslen, <=, db->db.db_size);
525 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
526 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
527 if (bonuslen < DN_MAX_BONUSLEN)
528 bzero(db->db.db_data, DN_MAX_BONUSLEN);
529 if (bonuslen)
530 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
531 DB_DNODE_EXIT(db);
532 db->db_state = DB_CACHED;
533 mutex_exit(&db->db_mtx);
534 return;
535 }
536
537 /*
538 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
539 * processes the delete record and clears the bp while we are waiting
540 * for the dn_mtx (resulting in a "no" from block_freed).
541 */
542 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
543 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
544 BP_IS_HOLE(db->db_blkptr)))) {
545 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
546
547 DB_DNODE_EXIT(db);
548 dbuf_set_data(db, arc_buf_alloc(db->db_objset->os_spa,
549 db->db.db_size, db, type));
550 bzero(db->db.db_data, db->db.db_size);
551 db->db_state = DB_CACHED;
552 *flags |= DB_RF_CACHED;
553 mutex_exit(&db->db_mtx);
554 return;
555 }
556
557 DB_DNODE_EXIT(db);
558
559 db->db_state = DB_READ;
560 mutex_exit(&db->db_mtx);
561
562 if (DBUF_IS_L2CACHEABLE(db))
563 aflags |= ARC_FLAG_L2CACHE;
564 if (DBUF_IS_L2COMPRESSIBLE(db))
565 aflags |= ARC_FLAG_L2COMPRESS;
566
567 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
568 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
569 db->db.db_object, db->db_level, db->db_blkid);
570
571 dbuf_add_ref(db, NULL);
572
573 (void) arc_read(zio, db->db_objset->os_spa, db->db_blkptr,
574 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
575 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
576 &aflags, &zb);
577 if (aflags & ARC_FLAG_CACHED)
578 *flags |= DB_RF_CACHED;
579}
580
581int
582dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
583{
584 int err = 0;
585 boolean_t havepzio = (zio != NULL);
586 boolean_t prefetch;
587 dnode_t *dn;
588
589 /*
590 * We don't have to hold the mutex to check db_state because it
591 * can't be freed while we have a hold on the buffer.
592 */
593 ASSERT(!refcount_is_zero(&db->db_holds));
594
595 if (db->db_state == DB_NOFILL)
596 return (SET_ERROR(EIO));
597
598 DB_DNODE_ENTER(db);
599 dn = DB_DNODE(db);
600 if ((flags & DB_RF_HAVESTRUCT) == 0)
601 rw_enter(&dn->dn_struct_rwlock, RW_READER);
602
603 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
604 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL &&
605 DBUF_IS_CACHEABLE(db);
606
607 mutex_enter(&db->db_mtx);
608 if (db->db_state == DB_CACHED) {
609 mutex_exit(&db->db_mtx);
610 if (prefetch)
611 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
612 db->db.db_size, TRUE);
613 if ((flags & DB_RF_HAVESTRUCT) == 0)
614 rw_exit(&dn->dn_struct_rwlock);
615 DB_DNODE_EXIT(db);
616 } else if (db->db_state == DB_UNCACHED) {
617 spa_t *spa = dn->dn_objset->os_spa;
618
619 if (zio == NULL)
620 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
621 dbuf_read_impl(db, zio, &flags);
622
623 /* dbuf_read_impl has dropped db_mtx for us */
624
625 if (prefetch)
626 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
627 db->db.db_size, flags & DB_RF_CACHED);
628
629 if ((flags & DB_RF_HAVESTRUCT) == 0)
630 rw_exit(&dn->dn_struct_rwlock);
631 DB_DNODE_EXIT(db);
632
633 if (!havepzio)
634 err = zio_wait(zio);
635 } else {
636 /*
637 * Another reader came in while the dbuf was in flight
638 * between UNCACHED and CACHED. Either a writer will finish
639 * writing the buffer (sending the dbuf to CACHED) or the
640 * first reader's request will reach the read_done callback
641 * and send the dbuf to CACHED. Otherwise, a failure
642 * occurred and the dbuf went to UNCACHED.
643 */
644 mutex_exit(&db->db_mtx);
645 if (prefetch)
646 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
647 db->db.db_size, TRUE);
648 if ((flags & DB_RF_HAVESTRUCT) == 0)
649 rw_exit(&dn->dn_struct_rwlock);
650 DB_DNODE_EXIT(db);
651
652 /* Skip the wait per the caller's request. */
653 mutex_enter(&db->db_mtx);
654 if ((flags & DB_RF_NEVERWAIT) == 0) {
655 while (db->db_state == DB_READ ||
656 db->db_state == DB_FILL) {
657 ASSERT(db->db_state == DB_READ ||
658 (flags & DB_RF_HAVESTRUCT) == 0);
659 DTRACE_PROBE2(blocked__read, dmu_buf_impl_t *,
660 db, zio_t *, zio);
661 cv_wait(&db->db_changed, &db->db_mtx);
662 }
663 if (db->db_state == DB_UNCACHED)
664 err = SET_ERROR(EIO);
665 }
666 mutex_exit(&db->db_mtx);
667 }
668
669 ASSERT(err || havepzio || db->db_state == DB_CACHED);
670 return (err);
671}
672
673static void
674dbuf_noread(dmu_buf_impl_t *db)
675{
676 ASSERT(!refcount_is_zero(&db->db_holds));
677 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
678 mutex_enter(&db->db_mtx);
679 while (db->db_state == DB_READ || db->db_state == DB_FILL)
680 cv_wait(&db->db_changed, &db->db_mtx);
681 if (db->db_state == DB_UNCACHED) {
682 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
683 spa_t *spa = db->db_objset->os_spa;
684
685 ASSERT(db->db_buf == NULL);
686 ASSERT(db->db.db_data == NULL);
687 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type));
688 db->db_state = DB_FILL;
689 } else if (db->db_state == DB_NOFILL) {
690 dbuf_set_data(db, NULL);
691 } else {
692 ASSERT3U(db->db_state, ==, DB_CACHED);
693 }
694 mutex_exit(&db->db_mtx);
695}
696
697/*
698 * This is our just-in-time copy function. It makes a copy of
699 * buffers, that have been modified in a previous transaction
700 * group, before we modify them in the current active group.
701 *
702 * This function is used in two places: when we are dirtying a
703 * buffer for the first time in a txg, and when we are freeing
704 * a range in a dnode that includes this buffer.
705 *
706 * Note that when we are called from dbuf_free_range() we do
707 * not put a hold on the buffer, we just traverse the active
708 * dbuf list for the dnode.
709 */
710static void
711dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
712{
713 dbuf_dirty_record_t *dr = db->db_last_dirty;
714
715 ASSERT(MUTEX_HELD(&db->db_mtx));
716 ASSERT(db->db.db_data != NULL);
717 ASSERT(db->db_level == 0);
718 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT);
719
720 if (dr == NULL ||
721 (dr->dt.dl.dr_data !=
722 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf)))
723 return;
724
725 /*
726 * If the last dirty record for this dbuf has not yet synced
727 * and its referencing the dbuf data, either:
728 * reset the reference to point to a new copy,
729 * or (if there a no active holders)
730 * just null out the current db_data pointer.
731 */
732 ASSERT(dr->dr_txg >= txg - 2);
733 if (db->db_blkid == DMU_BONUS_BLKID) {
734 /* Note that the data bufs here are zio_bufs */
735 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
736 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
737 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
738 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
739 int size = db->db.db_size;
740 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
741 spa_t *spa = db->db_objset->os_spa;
742
743 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type);
744 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
745 } else {
746 dbuf_set_data(db, NULL);
747 }
748}
749
750void
751dbuf_unoverride(dbuf_dirty_record_t *dr)
752{
753 dmu_buf_impl_t *db = dr->dr_dbuf;
754 blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
755 uint64_t txg = dr->dr_txg;
756
757 ASSERT(MUTEX_HELD(&db->db_mtx));
758 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
759 ASSERT(db->db_level == 0);
760
761 if (db->db_blkid == DMU_BONUS_BLKID ||
762 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
763 return;
764
765 ASSERT(db->db_data_pending != dr);
766
767 /* free this block */
768 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite)
769 zio_free(db->db_objset->os_spa, txg, bp);
770
771 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
772 dr->dt.dl.dr_nopwrite = B_FALSE;
773
774 /*
775 * Release the already-written buffer, so we leave it in
776 * a consistent dirty state. Note that all callers are
777 * modifying the buffer, so they will immediately do
778 * another (redundant) arc_release(). Therefore, leave
779 * the buf thawed to save the effort of freezing &
780 * immediately re-thawing it.
781 */
782 arc_release(dr->dt.dl.dr_data, db);
783}
784
785/*
786 * Evict (if its unreferenced) or clear (if its referenced) any level-0
787 * data blocks in the free range, so that any future readers will find
788 * empty blocks.
789 *
790 * This is a no-op if the dataset is in the middle of an incremental
791 * receive; see comment below for details.
792 */
793void
794dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid,
795 dmu_tx_t *tx)
796{
797 dmu_buf_impl_t *db, *db_next, db_search;
798 uint64_t txg = tx->tx_txg;
799 avl_index_t where;
800
801 if (end_blkid > dn->dn_maxblkid && (end_blkid != DMU_SPILL_BLKID))
802 end_blkid = dn->dn_maxblkid;
803 dprintf_dnode(dn, "start=%llu end=%llu\n", start_blkid, end_blkid);
804
805 db_search.db_level = 0;
806 db_search.db_blkid = start_blkid;
807 db_search.db_state = DB_SEARCH;
808
809 mutex_enter(&dn->dn_dbufs_mtx);
810 if (start_blkid >= dn->dn_unlisted_l0_blkid) {
811 /* There can't be any dbufs in this range; no need to search. */
812#ifdef DEBUG
813 db = avl_find(&dn->dn_dbufs, &db_search, &where);
814 ASSERT3P(db, ==, NULL);
815 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER);
816 ASSERT(db == NULL || db->db_level > 0);
817#endif
818 mutex_exit(&dn->dn_dbufs_mtx);
819 return;
820 } else if (dmu_objset_is_receiving(dn->dn_objset)) {
821 /*
822 * If we are receiving, we expect there to be no dbufs in
823 * the range to be freed, because receive modifies each
824 * block at most once, and in offset order. If this is
825 * not the case, it can lead to performance problems,
826 * so note that we unexpectedly took the slow path.
827 */
828 atomic_inc_64(&zfs_free_range_recv_miss);
829 }
830
831 db = avl_find(&dn->dn_dbufs, &db_search, &where);
832 ASSERT3P(db, ==, NULL);
833 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER);
834
835 for (; db != NULL; db = db_next) {
836 db_next = AVL_NEXT(&dn->dn_dbufs, db);
837 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
838
839 if (db->db_level != 0 || db->db_blkid > end_blkid) {
840 break;
841 }
842 ASSERT3U(db->db_blkid, >=, start_blkid);
843
844 /* found a level 0 buffer in the range */
845 mutex_enter(&db->db_mtx);
846 if (dbuf_undirty(db, tx)) {
847 /* mutex has been dropped and dbuf destroyed */
848 continue;
849 }
850
851 if (db->db_state == DB_UNCACHED ||
852 db->db_state == DB_NOFILL ||
853 db->db_state == DB_EVICTING) {
854 ASSERT(db->db.db_data == NULL);
855 mutex_exit(&db->db_mtx);
856 continue;
857 }
858 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
859 /* will be handled in dbuf_read_done or dbuf_rele */
860 db->db_freed_in_flight = TRUE;
861 mutex_exit(&db->db_mtx);
862 continue;
863 }
864 if (refcount_count(&db->db_holds) == 0) {
865 ASSERT(db->db_buf);
866 dbuf_clear(db);
867 continue;
868 }
869 /* The dbuf is referenced */
870
871 if (db->db_last_dirty != NULL) {
872 dbuf_dirty_record_t *dr = db->db_last_dirty;
873
874 if (dr->dr_txg == txg) {
875 /*
876 * This buffer is "in-use", re-adjust the file
877 * size to reflect that this buffer may
878 * contain new data when we sync.
879 */
880 if (db->db_blkid != DMU_SPILL_BLKID &&
881 db->db_blkid > dn->dn_maxblkid)
882 dn->dn_maxblkid = db->db_blkid;
883 dbuf_unoverride(dr);
884 } else {
885 /*
886 * This dbuf is not dirty in the open context.
887 * Either uncache it (if its not referenced in
888 * the open context) or reset its contents to
889 * empty.
890 */
891 dbuf_fix_old_data(db, txg);
892 }
893 }
894 /* clear the contents if its cached */
895 if (db->db_state == DB_CACHED) {
896 ASSERT(db->db.db_data != NULL);
897 arc_release(db->db_buf, db);
898 bzero(db->db.db_data, db->db.db_size);
899 arc_buf_freeze(db->db_buf);
900 }
901
902 mutex_exit(&db->db_mtx);
903 }
904 mutex_exit(&dn->dn_dbufs_mtx);
905}
906
907static int
908dbuf_block_freeable(dmu_buf_impl_t *db)
909{
910 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
911 uint64_t birth_txg = 0;
912
913 /*
914 * We don't need any locking to protect db_blkptr:
915 * If it's syncing, then db_last_dirty will be set
916 * so we'll ignore db_blkptr.
917 *
918 * This logic ensures that only block births for
919 * filled blocks are considered.
920 */
921 ASSERT(MUTEX_HELD(&db->db_mtx));
922 if (db->db_last_dirty && (db->db_blkptr == NULL ||
923 !BP_IS_HOLE(db->db_blkptr))) {
924 birth_txg = db->db_last_dirty->dr_txg;
925 } else if (db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr)) {
926 birth_txg = db->db_blkptr->blk_birth;
927 }
928
929 /*
930 * If this block don't exist or is in a snapshot, it can't be freed.
931 * Don't pass the bp to dsl_dataset_block_freeable() since we
932 * are holding the db_mtx lock and might deadlock if we are
933 * prefetching a dedup-ed block.
934 */
935 if (birth_txg != 0)
936 return (ds == NULL ||
937 dsl_dataset_block_freeable(ds, NULL, birth_txg));
938 else
939 return (B_FALSE);
940}
941
942void
943dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
944{
945 arc_buf_t *buf, *obuf;
946 int osize = db->db.db_size;
947 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
948 dnode_t *dn;
949
950 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
951
952 DB_DNODE_ENTER(db);
953 dn = DB_DNODE(db);
954
955 /* XXX does *this* func really need the lock? */
956 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
957
958 /*
959 * This call to dmu_buf_will_dirty() with the dn_struct_rwlock held
960 * is OK, because there can be no other references to the db
961 * when we are changing its size, so no concurrent DB_FILL can
962 * be happening.
963 */
964 /*
965 * XXX we should be doing a dbuf_read, checking the return
966 * value and returning that up to our callers
967 */
968 dmu_buf_will_dirty(&db->db, tx);
969
970 /* create the data buffer for the new block */
971 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type);
972
973 /* copy old block data to the new block */
974 obuf = db->db_buf;
975 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
976 /* zero the remainder */
977 if (size > osize)
978 bzero((uint8_t *)buf->b_data + osize, size - osize);
979
980 mutex_enter(&db->db_mtx);
981 dbuf_set_data(db, buf);
982 VERIFY(arc_buf_remove_ref(obuf, db));
983 db->db.db_size = size;
984
985 if (db->db_level == 0) {
986 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
987 db->db_last_dirty->dt.dl.dr_data = buf;
988 }
989 mutex_exit(&db->db_mtx);
990
991 dnode_willuse_space(dn, size-osize, tx);
992 DB_DNODE_EXIT(db);
993}
994
995void
996dbuf_release_bp(dmu_buf_impl_t *db)
997{
998 objset_t *os = db->db_objset;
999
1000 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
1001 ASSERT(arc_released(os->os_phys_buf) ||
1002 list_link_active(&os->os_dsl_dataset->ds_synced_link));
1003 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf));
1004
1005 (void) arc_release(db->db_buf, db);
1006}
1007
1008dbuf_dirty_record_t *
1009dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1010{
1011 dnode_t *dn;
1012 objset_t *os;
1013 dbuf_dirty_record_t **drp, *dr;
1014 int drop_struct_lock = FALSE;
1015 boolean_t do_free_accounting = B_FALSE;
1016 int txgoff = tx->tx_txg & TXG_MASK;
1017
1018 ASSERT(tx->tx_txg != 0);
1019 ASSERT(!refcount_is_zero(&db->db_holds));
1020 DMU_TX_DIRTY_BUF(tx, db);
1021
1022 DB_DNODE_ENTER(db);
1023 dn = DB_DNODE(db);
1024 /*
1025 * Shouldn't dirty a regular buffer in syncing context. Private
1026 * objects may be dirtied in syncing context, but only if they
1027 * were already pre-dirtied in open context.
1028 */
1029 ASSERT(!dmu_tx_is_syncing(tx) ||
1030 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
1031 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1032 dn->dn_objset->os_dsl_dataset == NULL);
1033 /*
1034 * We make this assert for private objects as well, but after we
1035 * check if we're already dirty. They are allowed to re-dirty
1036 * in syncing context.
1037 */
1038 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1039 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1040 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1041
1042 mutex_enter(&db->db_mtx);
1043 /*
1044 * XXX make this true for indirects too? The problem is that
1045 * transactions created with dmu_tx_create_assigned() from
1046 * syncing context don't bother holding ahead.
1047 */
1048 ASSERT(db->db_level != 0 ||
1049 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
1050 db->db_state == DB_NOFILL);
1051
1052 mutex_enter(&dn->dn_mtx);
1053 /*
1054 * Don't set dirtyctx to SYNC if we're just modifying this as we
1055 * initialize the objset.
1056 */
1057 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
1058 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
1059 dn->dn_dirtyctx =
1060 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
1061 ASSERT(dn->dn_dirtyctx_firstset == NULL);
1062 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
1063 }
1064 mutex_exit(&dn->dn_mtx);
1065
1066 if (db->db_blkid == DMU_SPILL_BLKID)
1067 dn->dn_have_spill = B_TRUE;
1068
1069 /*
1070 * If this buffer is already dirty, we're done.
1071 */
1072 drp = &db->db_last_dirty;
1073 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
1074 db->db.db_object == DMU_META_DNODE_OBJECT);
1075 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
1076 drp = &dr->dr_next;
1077 if (dr && dr->dr_txg == tx->tx_txg) {
1078 DB_DNODE_EXIT(db);
1079
1080 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
1081 /*
1082 * If this buffer has already been written out,
1083 * we now need to reset its state.
1084 */
1085 dbuf_unoverride(dr);
1086 if (db->db.db_object != DMU_META_DNODE_OBJECT &&
1087 db->db_state != DB_NOFILL)
1088 arc_buf_thaw(db->db_buf);
1089 }
1090 mutex_exit(&db->db_mtx);
1091 return (dr);
1092 }
1093
1094 /*
1095 * Only valid if not already dirty.
1096 */
1097 ASSERT(dn->dn_object == 0 ||
1098 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1099 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1100
1101 ASSERT3U(dn->dn_nlevels, >, db->db_level);
1102 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
1103 dn->dn_phys->dn_nlevels > db->db_level ||
1104 dn->dn_next_nlevels[txgoff] > db->db_level ||
1105 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
1106 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
1107
1108 /*
1109 * We should only be dirtying in syncing context if it's the
1110 * mos or we're initializing the os or it's a special object.
1111 * However, we are allowed to dirty in syncing context provided
1112 * we already dirtied it in open context. Hence we must make
1113 * this assertion only if we're not already dirty.
1114 */
1115 os = dn->dn_objset;
1116 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1117 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
1118 ASSERT(db->db.db_size != 0);
1119
1120 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1121
1122 if (db->db_blkid != DMU_BONUS_BLKID) {
1123 /*
1124 * Update the accounting.
1125 * Note: we delay "free accounting" until after we drop
1126 * the db_mtx. This keeps us from grabbing other locks
1127 * (and possibly deadlocking) in bp_get_dsize() while
1128 * also holding the db_mtx.
1129 */
1130 dnode_willuse_space(dn, db->db.db_size, tx);
1131 do_free_accounting = dbuf_block_freeable(db);
1132 }
1133
1134 /*
1135 * If this buffer is dirty in an old transaction group we need
1136 * to make a copy of it so that the changes we make in this
1137 * transaction group won't leak out when we sync the older txg.
1138 */
1139 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP);
1140 if (db->db_level == 0) {
1141 void *data_old = db->db_buf;
1142
1143 if (db->db_state != DB_NOFILL) {
1144 if (db->db_blkid == DMU_BONUS_BLKID) {
1145 dbuf_fix_old_data(db, tx->tx_txg);
1146 data_old = db->db.db_data;
1147 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1148 /*
1149 * Release the data buffer from the cache so
1150 * that we can modify it without impacting
1151 * possible other users of this cached data
1152 * block. Note that indirect blocks and
1153 * private objects are not released until the
1154 * syncing state (since they are only modified
1155 * then).
1156 */
1157 arc_release(db->db_buf, db);
1158 dbuf_fix_old_data(db, tx->tx_txg);
1159 data_old = db->db_buf;
1160 }
1161 ASSERT(data_old != NULL);
1162 }
1163 dr->dt.dl.dr_data = data_old;
1164 } else {
1165 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1166 list_create(&dr->dt.di.dr_children,
1167 sizeof (dbuf_dirty_record_t),
1168 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1169 }
1170 if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL)
1171 dr->dr_accounted = db->db.db_size;
1172 dr->dr_dbuf = db;
1173 dr->dr_txg = tx->tx_txg;
1174 dr->dr_next = *drp;
1175 *drp = dr;
1176
1177 /*
1178 * We could have been freed_in_flight between the dbuf_noread
1179 * and dbuf_dirty. We win, as though the dbuf_noread() had
1180 * happened after the free.
1181 */
1182 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1183 db->db_blkid != DMU_SPILL_BLKID) {
1184 mutex_enter(&dn->dn_mtx);
1185 if (dn->dn_free_ranges[txgoff] != NULL) {
1186 range_tree_clear(dn->dn_free_ranges[txgoff],
1187 db->db_blkid, 1);
1188 }
1189 mutex_exit(&dn->dn_mtx);
1190 db->db_freed_in_flight = FALSE;
1191 }
1192
1193 /*
1194 * This buffer is now part of this txg
1195 */
1196 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1197 db->db_dirtycnt += 1;
1198 ASSERT3U(db->db_dirtycnt, <=, 3);
1199
1200 mutex_exit(&db->db_mtx);
1201
1202 if (db->db_blkid == DMU_BONUS_BLKID ||
1203 db->db_blkid == DMU_SPILL_BLKID) {
1204 mutex_enter(&dn->dn_mtx);
1205 ASSERT(!list_link_active(&dr->dr_dirty_node));
1206 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1207 mutex_exit(&dn->dn_mtx);
1208 dnode_setdirty(dn, tx);
1209 DB_DNODE_EXIT(db);
1210 return (dr);
1211 } else if (do_free_accounting) {
1212 blkptr_t *bp = db->db_blkptr;
1213 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1214 bp_get_dsize(os->os_spa, bp) : db->db.db_size;
1215 /*
1216 * This is only a guess -- if the dbuf is dirty
1217 * in a previous txg, we don't know how much
1218 * space it will use on disk yet. We should
1219 * really have the struct_rwlock to access
1220 * db_blkptr, but since this is just a guess,
1221 * it's OK if we get an odd answer.
1222 */
1223 ddt_prefetch(os->os_spa, bp);
1224 dnode_willuse_space(dn, -willfree, tx);
1225 }
1226
1227 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1228 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1229 drop_struct_lock = TRUE;
1230 }
1231
1232 if (db->db_level == 0) {
1233 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1234 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1235 }
1236
1237 if (db->db_level+1 < dn->dn_nlevels) {
1238 dmu_buf_impl_t *parent = db->db_parent;
1239 dbuf_dirty_record_t *di;
1240 int parent_held = FALSE;
1241
1242 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1243 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1244
1245 parent = dbuf_hold_level(dn, db->db_level+1,
1246 db->db_blkid >> epbs, FTAG);
1247 ASSERT(parent != NULL);
1248 parent_held = TRUE;
1249 }
1250 if (drop_struct_lock)
1251 rw_exit(&dn->dn_struct_rwlock);
1252 ASSERT3U(db->db_level+1, ==, parent->db_level);
1253 di = dbuf_dirty(parent, tx);
1254 if (parent_held)
1255 dbuf_rele(parent, FTAG);
1256
1257 mutex_enter(&db->db_mtx);
1258 /*
1259 * Since we've dropped the mutex, it's possible that
1260 * dbuf_undirty() might have changed this out from under us.
1261 */
1262 if (db->db_last_dirty == dr ||
1263 dn->dn_object == DMU_META_DNODE_OBJECT) {
1264 mutex_enter(&di->dt.di.dr_mtx);
1265 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1266 ASSERT(!list_link_active(&dr->dr_dirty_node));
1267 list_insert_tail(&di->dt.di.dr_children, dr);
1268 mutex_exit(&di->dt.di.dr_mtx);
1269 dr->dr_parent = di;
1270 }
1271 mutex_exit(&db->db_mtx);
1272 } else {
1273 ASSERT(db->db_level+1 == dn->dn_nlevels);
1274 ASSERT(db->db_blkid < dn->dn_nblkptr);
1275 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf);
1276 mutex_enter(&dn->dn_mtx);
1277 ASSERT(!list_link_active(&dr->dr_dirty_node));
1278 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1279 mutex_exit(&dn->dn_mtx);
1280 if (drop_struct_lock)
1281 rw_exit(&dn->dn_struct_rwlock);
1282 }
1283
1284 dnode_setdirty(dn, tx);
1285 DB_DNODE_EXIT(db);
1286 return (dr);
1287}
1288
1289/*
1290 * Undirty a buffer in the transaction group referenced by the given
1291 * transaction. Return whether this evicted the dbuf.
1292 */
1293static boolean_t
1294dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1295{
1296 dnode_t *dn;
1297 uint64_t txg = tx->tx_txg;
1298 dbuf_dirty_record_t *dr, **drp;
1299
1300 ASSERT(txg != 0);
|
| 1301
1302 /*
1303 * Due to our use of dn_nlevels below, this can only be called
1304 * in open context, unless we are operating on the MOS.
1305 * From syncing context, dn_nlevels may be different from the
1306 * dn_nlevels used when dbuf was dirtied.
1307 */
1308 ASSERT(db->db_objset ==
1309 dmu_objset_pool(db->db_objset)->dp_meta_objset ||
1310 txg != spa_syncing_txg(dmu_objset_spa(db->db_objset)));
|
1301 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1302 ASSERT0(db->db_level);
1303 ASSERT(MUTEX_HELD(&db->db_mtx));
1304
1305 /*
1306 * If this buffer is not dirty, we're done.
1307 */
1308 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1309 if (dr->dr_txg <= txg)
1310 break;
1311 if (dr == NULL || dr->dr_txg < txg)
1312 return (B_FALSE);
1313 ASSERT(dr->dr_txg == txg);
1314 ASSERT(dr->dr_dbuf == db);
1315
1316 DB_DNODE_ENTER(db);
1317 dn = DB_DNODE(db);
1318
1319 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1320
1321 ASSERT(db->db.db_size != 0);
1322
| 1311 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1312 ASSERT0(db->db_level);
1313 ASSERT(MUTEX_HELD(&db->db_mtx));
1314
1315 /*
1316 * If this buffer is not dirty, we're done.
1317 */
1318 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1319 if (dr->dr_txg <= txg)
1320 break;
1321 if (dr == NULL || dr->dr_txg < txg)
1322 return (B_FALSE);
1323 ASSERT(dr->dr_txg == txg);
1324 ASSERT(dr->dr_dbuf == db);
1325
1326 DB_DNODE_ENTER(db);
1327 dn = DB_DNODE(db);
1328
1329 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1330
1331 ASSERT(db->db.db_size != 0);
1332
|
1323 /*
1324 * Any space we accounted for in dp_dirty_* will be cleaned up by
1325 * dsl_pool_sync(). This is relatively rare so the discrepancy
1326 * is not a big deal.
1327 */
| 1333 dsl_pool_undirty_space(dmu_objset_pool(dn->dn_objset),
1334 dr->dr_accounted, txg);
|
1328
1329 *drp = dr->dr_next;
1330
1331 /*
1332 * Note that there are three places in dbuf_dirty()
1333 * where this dirty record may be put on a list.
1334 * Make sure to do a list_remove corresponding to
1335 * every one of those list_insert calls.
1336 */
1337 if (dr->dr_parent) {
1338 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1339 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1340 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1341 } else if (db->db_blkid == DMU_SPILL_BLKID ||
| 1335
1336 *drp = dr->dr_next;
1337
1338 /*
1339 * Note that there are three places in dbuf_dirty()
1340 * where this dirty record may be put on a list.
1341 * Make sure to do a list_remove corresponding to
1342 * every one of those list_insert calls.
1343 */
1344 if (dr->dr_parent) {
1345 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1346 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1347 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1348 } else if (db->db_blkid == DMU_SPILL_BLKID ||
|
1342 db->db_level+1 == dn->dn_nlevels) {
| 1349 db->db_level + 1 == dn->dn_nlevels) {
|
1343 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
1344 mutex_enter(&dn->dn_mtx);
1345 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
1346 mutex_exit(&dn->dn_mtx);
1347 }
1348 DB_DNODE_EXIT(db);
1349
1350 if (db->db_state != DB_NOFILL) {
1351 dbuf_unoverride(dr);
1352
1353 ASSERT(db->db_buf != NULL);
1354 ASSERT(dr->dt.dl.dr_data != NULL);
1355 if (dr->dt.dl.dr_data != db->db_buf)
1356 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db));
1357 }
1358
| 1350 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
1351 mutex_enter(&dn->dn_mtx);
1352 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
1353 mutex_exit(&dn->dn_mtx);
1354 }
1355 DB_DNODE_EXIT(db);
1356
1357 if (db->db_state != DB_NOFILL) {
1358 dbuf_unoverride(dr);
1359
1360 ASSERT(db->db_buf != NULL);
1361 ASSERT(dr->dt.dl.dr_data != NULL);
1362 if (dr->dt.dl.dr_data != db->db_buf)
1363 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db));
1364 }
1365
|
1359 if (db->db_level != 0) {
1360 mutex_destroy(&dr->dt.di.dr_mtx);
1361 list_destroy(&dr->dt.di.dr_children);
1362 }
1363
| |
1364 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1365
1366 ASSERT(db->db_dirtycnt > 0);
1367 db->db_dirtycnt -= 1;
1368
1369 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1370 arc_buf_t *buf = db->db_buf;
1371
1372 ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
1373 dbuf_set_data(db, NULL);
1374 VERIFY(arc_buf_remove_ref(buf, db));
1375 dbuf_evict(db);
1376 return (B_TRUE);
1377 }
1378
1379 return (B_FALSE);
1380}
1381
1382void
1383dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx)
1384{
1385 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1386 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1387
1388 ASSERT(tx->tx_txg != 0);
1389 ASSERT(!refcount_is_zero(&db->db_holds));
1390
1391 DB_DNODE_ENTER(db);
1392 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
1393 rf |= DB_RF_HAVESTRUCT;
1394 DB_DNODE_EXIT(db);
1395 (void) dbuf_read(db, NULL, rf);
1396 (void) dbuf_dirty(db, tx);
1397}
1398
1399void
1400dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1401{
1402 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1403
1404 db->db_state = DB_NOFILL;
1405
1406 dmu_buf_will_fill(db_fake, tx);
1407}
1408
1409void
1410dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1411{
1412 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1413
1414 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1415 ASSERT(tx->tx_txg != 0);
1416 ASSERT(db->db_level == 0);
1417 ASSERT(!refcount_is_zero(&db->db_holds));
1418
1419 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1420 dmu_tx_private_ok(tx));
1421
1422 dbuf_noread(db);
1423 (void) dbuf_dirty(db, tx);
1424}
1425
1426#pragma weak dmu_buf_fill_done = dbuf_fill_done
1427/* ARGSUSED */
1428void
1429dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1430{
1431 mutex_enter(&db->db_mtx);
1432 DBUF_VERIFY(db);
1433
1434 if (db->db_state == DB_FILL) {
1435 if (db->db_level == 0 && db->db_freed_in_flight) {
1436 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1437 /* we were freed while filling */
1438 /* XXX dbuf_undirty? */
1439 bzero(db->db.db_data, db->db.db_size);
1440 db->db_freed_in_flight = FALSE;
1441 }
1442 db->db_state = DB_CACHED;
1443 cv_broadcast(&db->db_changed);
1444 }
1445 mutex_exit(&db->db_mtx);
1446}
1447
1448void
1449dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data,
1450 bp_embedded_type_t etype, enum zio_compress comp,
1451 int uncompressed_size, int compressed_size, int byteorder,
1452 dmu_tx_t *tx)
1453{
1454 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
1455 struct dirty_leaf *dl;
1456 dmu_object_type_t type;
1457
1458 DB_DNODE_ENTER(db);
1459 type = DB_DNODE(db)->dn_type;
1460 DB_DNODE_EXIT(db);
1461
1462 ASSERT0(db->db_level);
1463 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1464
1465 dmu_buf_will_not_fill(dbuf, tx);
1466
1467 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
1468 dl = &db->db_last_dirty->dt.dl;
1469 encode_embedded_bp_compressed(&dl->dr_overridden_by,
1470 data, comp, uncompressed_size, compressed_size);
1471 BPE_SET_ETYPE(&dl->dr_overridden_by, etype);
1472 BP_SET_TYPE(&dl->dr_overridden_by, type);
1473 BP_SET_LEVEL(&dl->dr_overridden_by, 0);
1474 BP_SET_BYTEORDER(&dl->dr_overridden_by, byteorder);
1475
1476 dl->dr_override_state = DR_OVERRIDDEN;
1477 dl->dr_overridden_by.blk_birth = db->db_last_dirty->dr_txg;
1478}
1479
1480/*
1481 * Directly assign a provided arc buf to a given dbuf if it's not referenced
1482 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
1483 */
1484void
1485dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
1486{
1487 ASSERT(!refcount_is_zero(&db->db_holds));
1488 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1489 ASSERT(db->db_level == 0);
1490 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
1491 ASSERT(buf != NULL);
1492 ASSERT(arc_buf_size(buf) == db->db.db_size);
1493 ASSERT(tx->tx_txg != 0);
1494
1495 arc_return_buf(buf, db);
1496 ASSERT(arc_released(buf));
1497
1498 mutex_enter(&db->db_mtx);
1499
1500 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1501 cv_wait(&db->db_changed, &db->db_mtx);
1502
1503 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
1504
1505 if (db->db_state == DB_CACHED &&
1506 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
1507 mutex_exit(&db->db_mtx);
1508 (void) dbuf_dirty(db, tx);
1509 bcopy(buf->b_data, db->db.db_data, db->db.db_size);
1510 VERIFY(arc_buf_remove_ref(buf, db));
1511 xuio_stat_wbuf_copied();
1512 return;
1513 }
1514
1515 xuio_stat_wbuf_nocopy();
1516 if (db->db_state == DB_CACHED) {
1517 dbuf_dirty_record_t *dr = db->db_last_dirty;
1518
1519 ASSERT(db->db_buf != NULL);
1520 if (dr != NULL && dr->dr_txg == tx->tx_txg) {
1521 ASSERT(dr->dt.dl.dr_data == db->db_buf);
1522 if (!arc_released(db->db_buf)) {
1523 ASSERT(dr->dt.dl.dr_override_state ==
1524 DR_OVERRIDDEN);
1525 arc_release(db->db_buf, db);
1526 }
1527 dr->dt.dl.dr_data = buf;
1528 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1529 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
1530 arc_release(db->db_buf, db);
1531 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1532 }
1533 db->db_buf = NULL;
1534 }
1535 ASSERT(db->db_buf == NULL);
1536 dbuf_set_data(db, buf);
1537 db->db_state = DB_FILL;
1538 mutex_exit(&db->db_mtx);
1539 (void) dbuf_dirty(db, tx);
1540 dmu_buf_fill_done(&db->db, tx);
1541}
1542
1543/*
1544 * "Clear" the contents of this dbuf. This will mark the dbuf
1545 * EVICTING and clear *most* of its references. Unfortunately,
1546 * when we are not holding the dn_dbufs_mtx, we can't clear the
1547 * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
1548 * in this case. For callers from the DMU we will usually see:
1549 * dbuf_clear()->arc_clear_callback()->dbuf_do_evict()->dbuf_destroy()
1550 * For the arc callback, we will usually see:
1551 * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
1552 * Sometimes, though, we will get a mix of these two:
1553 * DMU: dbuf_clear()->arc_clear_callback()
1554 * ARC: dbuf_do_evict()->dbuf_destroy()
1555 *
1556 * This routine will dissociate the dbuf from the arc, by calling
1557 * arc_clear_callback(), but will not evict the data from the ARC.
1558 */
1559void
1560dbuf_clear(dmu_buf_impl_t *db)
1561{
1562 dnode_t *dn;
1563 dmu_buf_impl_t *parent = db->db_parent;
1564 dmu_buf_impl_t *dndb;
1565 boolean_t dbuf_gone = B_FALSE;
1566
1567 ASSERT(MUTEX_HELD(&db->db_mtx));
1568 ASSERT(refcount_is_zero(&db->db_holds));
1569
1570 dbuf_evict_user(db);
1571
1572 if (db->db_state == DB_CACHED) {
1573 ASSERT(db->db.db_data != NULL);
1574 if (db->db_blkid == DMU_BONUS_BLKID) {
1575 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1576 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1577 }
1578 db->db.db_data = NULL;
1579 db->db_state = DB_UNCACHED;
1580 }
1581
1582 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
1583 ASSERT(db->db_data_pending == NULL);
1584
1585 db->db_state = DB_EVICTING;
1586 db->db_blkptr = NULL;
1587
1588 DB_DNODE_ENTER(db);
1589 dn = DB_DNODE(db);
1590 dndb = dn->dn_dbuf;
1591 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1592 avl_remove(&dn->dn_dbufs, db);
1593 atomic_dec_32(&dn->dn_dbufs_count);
1594 membar_producer();
1595 DB_DNODE_EXIT(db);
1596 /*
1597 * Decrementing the dbuf count means that the hold corresponding
1598 * to the removed dbuf is no longer discounted in dnode_move(),
1599 * so the dnode cannot be moved until after we release the hold.
1600 * The membar_producer() ensures visibility of the decremented
1601 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually
1602 * release any lock.
1603 */
1604 dnode_rele(dn, db);
1605 db->db_dnode_handle = NULL;
1606 } else {
1607 DB_DNODE_EXIT(db);
1608 }
1609
1610 if (db->db_buf)
1611 dbuf_gone = arc_clear_callback(db->db_buf);
1612
1613 if (!dbuf_gone)
1614 mutex_exit(&db->db_mtx);
1615
1616 /*
1617 * If this dbuf is referenced from an indirect dbuf,
1618 * decrement the ref count on the indirect dbuf.
1619 */
1620 if (parent && parent != dndb)
1621 dbuf_rele(parent, db);
1622}
1623
1624static int
1625dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1626 dmu_buf_impl_t **parentp, blkptr_t **bpp)
1627{
1628 int nlevels, epbs;
1629
1630 *parentp = NULL;
1631 *bpp = NULL;
1632
1633 ASSERT(blkid != DMU_BONUS_BLKID);
1634
1635 if (blkid == DMU_SPILL_BLKID) {
1636 mutex_enter(&dn->dn_mtx);
1637 if (dn->dn_have_spill &&
1638 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
1639 *bpp = &dn->dn_phys->dn_spill;
1640 else
1641 *bpp = NULL;
1642 dbuf_add_ref(dn->dn_dbuf, NULL);
1643 *parentp = dn->dn_dbuf;
1644 mutex_exit(&dn->dn_mtx);
1645 return (0);
1646 }
1647
1648 if (dn->dn_phys->dn_nlevels == 0)
1649 nlevels = 1;
1650 else
1651 nlevels = dn->dn_phys->dn_nlevels;
1652
1653 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1654
1655 ASSERT3U(level * epbs, <, 64);
1656 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1657 if (level >= nlevels ||
1658 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
1659 /* the buffer has no parent yet */
1660 return (SET_ERROR(ENOENT));
1661 } else if (level < nlevels-1) {
1662 /* this block is referenced from an indirect block */
1663 int err = dbuf_hold_impl(dn, level+1,
1664 blkid >> epbs, fail_sparse, NULL, parentp);
1665 if (err)
1666 return (err);
1667 err = dbuf_read(*parentp, NULL,
1668 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1669 if (err) {
1670 dbuf_rele(*parentp, NULL);
1671 *parentp = NULL;
1672 return (err);
1673 }
1674 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1675 (blkid & ((1ULL << epbs) - 1));
1676 return (0);
1677 } else {
1678 /* the block is referenced from the dnode */
1679 ASSERT3U(level, ==, nlevels-1);
1680 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1681 blkid < dn->dn_phys->dn_nblkptr);
1682 if (dn->dn_dbuf) {
1683 dbuf_add_ref(dn->dn_dbuf, NULL);
1684 *parentp = dn->dn_dbuf;
1685 }
1686 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1687 return (0);
1688 }
1689}
1690
1691static dmu_buf_impl_t *
1692dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1693 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1694{
1695 objset_t *os = dn->dn_objset;
1696 dmu_buf_impl_t *db, *odb;
1697
1698 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1699 ASSERT(dn->dn_type != DMU_OT_NONE);
1700
1701 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP);
1702
1703 db->db_objset = os;
1704 db->db.db_object = dn->dn_object;
1705 db->db_level = level;
1706 db->db_blkid = blkid;
1707 db->db_last_dirty = NULL;
1708 db->db_dirtycnt = 0;
1709 db->db_dnode_handle = dn->dn_handle;
1710 db->db_parent = parent;
1711 db->db_blkptr = blkptr;
1712
1713 db->db_user_ptr = NULL;
1714 db->db_evict_func = NULL;
1715 db->db_immediate_evict = 0;
1716 db->db_freed_in_flight = 0;
1717
1718 if (blkid == DMU_BONUS_BLKID) {
1719 ASSERT3P(parent, ==, dn->dn_dbuf);
1720 db->db.db_size = DN_MAX_BONUSLEN -
1721 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1722 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1723 db->db.db_offset = DMU_BONUS_BLKID;
1724 db->db_state = DB_UNCACHED;
1725 /* the bonus dbuf is not placed in the hash table */
1726 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1727 return (db);
1728 } else if (blkid == DMU_SPILL_BLKID) {
1729 db->db.db_size = (blkptr != NULL) ?
1730 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE;
1731 db->db.db_offset = 0;
1732 } else {
1733 int blocksize =
1734 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz;
1735 db->db.db_size = blocksize;
1736 db->db.db_offset = db->db_blkid * blocksize;
1737 }
1738
1739 /*
1740 * Hold the dn_dbufs_mtx while we get the new dbuf
1741 * in the hash table *and* added to the dbufs list.
1742 * This prevents a possible deadlock with someone
1743 * trying to look up this dbuf before its added to the
1744 * dn_dbufs list.
1745 */
1746 mutex_enter(&dn->dn_dbufs_mtx);
1747 db->db_state = DB_EVICTING;
1748 if ((odb = dbuf_hash_insert(db)) != NULL) {
1749 /* someone else inserted it first */
1750 kmem_cache_free(dbuf_cache, db);
1751 mutex_exit(&dn->dn_dbufs_mtx);
1752 return (odb);
1753 }
1754 avl_add(&dn->dn_dbufs, db);
1755 if (db->db_level == 0 && db->db_blkid >=
1756 dn->dn_unlisted_l0_blkid)
1757 dn->dn_unlisted_l0_blkid = db->db_blkid + 1;
1758 db->db_state = DB_UNCACHED;
1759 mutex_exit(&dn->dn_dbufs_mtx);
1760 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1761
1762 if (parent && parent != dn->dn_dbuf)
1763 dbuf_add_ref(parent, db);
1764
1765 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1766 refcount_count(&dn->dn_holds) > 0);
1767 (void) refcount_add(&dn->dn_holds, db);
1768 atomic_inc_32(&dn->dn_dbufs_count);
1769
1770 dprintf_dbuf(db, "db=%p\n", db);
1771
1772 return (db);
1773}
1774
1775static int
1776dbuf_do_evict(void *private)
1777{
1778 dmu_buf_impl_t *db = private;
1779
1780 if (!MUTEX_HELD(&db->db_mtx))
1781 mutex_enter(&db->db_mtx);
1782
1783 ASSERT(refcount_is_zero(&db->db_holds));
1784
1785 if (db->db_state != DB_EVICTING) {
1786 ASSERT(db->db_state == DB_CACHED);
1787 DBUF_VERIFY(db);
1788 db->db_buf = NULL;
1789 dbuf_evict(db);
1790 } else {
1791 mutex_exit(&db->db_mtx);
1792 dbuf_destroy(db);
1793 }
1794 return (0);
1795}
1796
1797static void
1798dbuf_destroy(dmu_buf_impl_t *db)
1799{
1800 ASSERT(refcount_is_zero(&db->db_holds));
1801
1802 if (db->db_blkid != DMU_BONUS_BLKID) {
1803 /*
1804 * If this dbuf is still on the dn_dbufs list,
1805 * remove it from that list.
1806 */
1807 if (db->db_dnode_handle != NULL) {
1808 dnode_t *dn;
1809
1810 DB_DNODE_ENTER(db);
1811 dn = DB_DNODE(db);
1812 mutex_enter(&dn->dn_dbufs_mtx);
1813 avl_remove(&dn->dn_dbufs, db);
1814 atomic_dec_32(&dn->dn_dbufs_count);
1815 mutex_exit(&dn->dn_dbufs_mtx);
1816 DB_DNODE_EXIT(db);
1817 /*
1818 * Decrementing the dbuf count means that the hold
1819 * corresponding to the removed dbuf is no longer
1820 * discounted in dnode_move(), so the dnode cannot be
1821 * moved until after we release the hold.
1822 */
1823 dnode_rele(dn, db);
1824 db->db_dnode_handle = NULL;
1825 }
1826 dbuf_hash_remove(db);
1827 }
1828 db->db_parent = NULL;
1829 db->db_buf = NULL;
1830
1831 ASSERT(db->db.db_data == NULL);
1832 ASSERT(db->db_hash_next == NULL);
1833 ASSERT(db->db_blkptr == NULL);
1834 ASSERT(db->db_data_pending == NULL);
1835
1836 kmem_cache_free(dbuf_cache, db);
1837 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1838}
1839
1840void
1841dbuf_prefetch(dnode_t *dn, uint64_t blkid, zio_priority_t prio)
1842{
1843 dmu_buf_impl_t *db = NULL;
1844 blkptr_t *bp = NULL;
1845
1846 ASSERT(blkid != DMU_BONUS_BLKID);
1847 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1848
1849 if (dnode_block_freed(dn, blkid))
1850 return;
1851
1852 /* dbuf_find() returns with db_mtx held */
1853 if (db = dbuf_find(dn, 0, blkid)) {
1854 /*
1855 * This dbuf is already in the cache. We assume that
1856 * it is already CACHED, or else about to be either
1857 * read or filled.
1858 */
1859 mutex_exit(&db->db_mtx);
1860 return;
1861 }
1862
1863 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) {
1864 if (bp && !BP_IS_HOLE(bp) && !BP_IS_EMBEDDED(bp)) {
1865 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
1866 arc_flags_t aflags =
1867 ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
1868 zbookmark_phys_t zb;
1869
1870 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1871 dn->dn_object, 0, blkid);
1872
1873 (void) arc_read(NULL, dn->dn_objset->os_spa,
1874 bp, NULL, NULL, prio,
1875 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1876 &aflags, &zb);
1877 }
1878 if (db)
1879 dbuf_rele(db, NULL);
1880 }
1881}
1882
1883/*
1884 * Returns with db_holds incremented, and db_mtx not held.
1885 * Note: dn_struct_rwlock must be held.
1886 */
1887int
1888dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
1889 void *tag, dmu_buf_impl_t **dbp)
1890{
1891 dmu_buf_impl_t *db, *parent = NULL;
1892
1893 ASSERT(blkid != DMU_BONUS_BLKID);
1894 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1895 ASSERT3U(dn->dn_nlevels, >, level);
1896
1897 *dbp = NULL;
1898top:
1899 /* dbuf_find() returns with db_mtx held */
1900 db = dbuf_find(dn, level, blkid);
1901
1902 if (db == NULL) {
1903 blkptr_t *bp = NULL;
1904 int err;
1905
1906 ASSERT3P(parent, ==, NULL);
1907 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp);
1908 if (fail_sparse) {
1909 if (err == 0 && bp && BP_IS_HOLE(bp))
1910 err = SET_ERROR(ENOENT);
1911 if (err) {
1912 if (parent)
1913 dbuf_rele(parent, NULL);
1914 return (err);
1915 }
1916 }
1917 if (err && err != ENOENT)
1918 return (err);
1919 db = dbuf_create(dn, level, blkid, parent, bp);
1920 }
1921
1922 if (db->db_buf && refcount_is_zero(&db->db_holds)) {
1923 arc_buf_add_ref(db->db_buf, db);
1924 if (db->db_buf->b_data == NULL) {
1925 dbuf_clear(db);
1926 if (parent) {
1927 dbuf_rele(parent, NULL);
1928 parent = NULL;
1929 }
1930 goto top;
1931 }
1932 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data);
1933 }
1934
1935 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf));
1936
1937 /*
1938 * If this buffer is currently syncing out, and we are are
1939 * still referencing it from db_data, we need to make a copy
1940 * of it in case we decide we want to dirty it again in this txg.
1941 */
1942 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1943 dn->dn_object != DMU_META_DNODE_OBJECT &&
1944 db->db_state == DB_CACHED && db->db_data_pending) {
1945 dbuf_dirty_record_t *dr = db->db_data_pending;
1946
1947 if (dr->dt.dl.dr_data == db->db_buf) {
1948 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
1949
1950 dbuf_set_data(db,
1951 arc_buf_alloc(dn->dn_objset->os_spa,
1952 db->db.db_size, db, type));
1953 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data,
1954 db->db.db_size);
1955 }
1956 }
1957
1958 (void) refcount_add(&db->db_holds, tag);
1959 DBUF_VERIFY(db);
1960 mutex_exit(&db->db_mtx);
1961
1962 /* NOTE: we can't rele the parent until after we drop the db_mtx */
1963 if (parent)
1964 dbuf_rele(parent, NULL);
1965
1966 ASSERT3P(DB_DNODE(db), ==, dn);
1967 ASSERT3U(db->db_blkid, ==, blkid);
1968 ASSERT3U(db->db_level, ==, level);
1969 *dbp = db;
1970
1971 return (0);
1972}
1973
1974dmu_buf_impl_t *
1975dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
1976{
1977 dmu_buf_impl_t *db;
1978 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
1979 return (err ? NULL : db);
1980}
1981
1982dmu_buf_impl_t *
1983dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
1984{
1985 dmu_buf_impl_t *db;
1986 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
1987 return (err ? NULL : db);
1988}
1989
1990void
1991dbuf_create_bonus(dnode_t *dn)
1992{
1993 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
1994
1995 ASSERT(dn->dn_bonus == NULL);
1996 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL);
1997}
1998
1999int
2000dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx)
2001{
2002 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2003 dnode_t *dn;
2004
2005 if (db->db_blkid != DMU_SPILL_BLKID)
2006 return (SET_ERROR(ENOTSUP));
2007 if (blksz == 0)
2008 blksz = SPA_MINBLOCKSIZE;
2009 ASSERT3U(blksz, <=, spa_maxblocksize(dmu_objset_spa(db->db_objset)));
2010 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE);
2011
2012 DB_DNODE_ENTER(db);
2013 dn = DB_DNODE(db);
2014 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
2015 dbuf_new_size(db, blksz, tx);
2016 rw_exit(&dn->dn_struct_rwlock);
2017 DB_DNODE_EXIT(db);
2018
2019 return (0);
2020}
2021
2022void
2023dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx)
2024{
2025 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx);
2026}
2027
2028#pragma weak dmu_buf_add_ref = dbuf_add_ref
2029void
2030dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
2031{
2032 int64_t holds = refcount_add(&db->db_holds, tag);
2033 ASSERT(holds > 1);
2034}
2035
2036/*
2037 * If you call dbuf_rele() you had better not be referencing the dnode handle
2038 * unless you have some other direct or indirect hold on the dnode. (An indirect
2039 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.)
2040 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the
2041 * dnode's parent dbuf evicting its dnode handles.
2042 */
2043void
2044dbuf_rele(dmu_buf_impl_t *db, void *tag)
2045{
2046 mutex_enter(&db->db_mtx);
2047 dbuf_rele_and_unlock(db, tag);
2048}
2049
2050void
2051dmu_buf_rele(dmu_buf_t *db, void *tag)
2052{
2053 dbuf_rele((dmu_buf_impl_t *)db, tag);
2054}
2055
2056/*
2057 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
2058 * db_dirtycnt and db_holds to be updated atomically.
2059 */
2060void
2061dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
2062{
2063 int64_t holds;
2064
2065 ASSERT(MUTEX_HELD(&db->db_mtx));
2066 DBUF_VERIFY(db);
2067
2068 /*
2069 * Remove the reference to the dbuf before removing its hold on the
2070 * dnode so we can guarantee in dnode_move() that a referenced bonus
2071 * buffer has a corresponding dnode hold.
2072 */
2073 holds = refcount_remove(&db->db_holds, tag);
2074 ASSERT(holds >= 0);
2075
2076 /*
2077 * We can't freeze indirects if there is a possibility that they
2078 * may be modified in the current syncing context.
2079 */
2080 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
2081 arc_buf_freeze(db->db_buf);
2082
2083 if (holds == db->db_dirtycnt &&
2084 db->db_level == 0 && db->db_immediate_evict)
2085 dbuf_evict_user(db);
2086
2087 if (holds == 0) {
2088 if (db->db_blkid == DMU_BONUS_BLKID) {
2089 mutex_exit(&db->db_mtx);
2090
2091 /*
2092 * If the dnode moves here, we cannot cross this barrier
2093 * until the move completes.
2094 */
2095 DB_DNODE_ENTER(db);
2096 atomic_dec_32(&DB_DNODE(db)->dn_dbufs_count);
2097 DB_DNODE_EXIT(db);
2098 /*
2099 * The bonus buffer's dnode hold is no longer discounted
2100 * in dnode_move(). The dnode cannot move until after
2101 * the dnode_rele().
2102 */
2103 dnode_rele(DB_DNODE(db), db);
2104 } else if (db->db_buf == NULL) {
2105 /*
2106 * This is a special case: we never associated this
2107 * dbuf with any data allocated from the ARC.
2108 */
2109 ASSERT(db->db_state == DB_UNCACHED ||
2110 db->db_state == DB_NOFILL);
2111 dbuf_evict(db);
2112 } else if (arc_released(db->db_buf)) {
2113 arc_buf_t *buf = db->db_buf;
2114 /*
2115 * This dbuf has anonymous data associated with it.
2116 */
2117 dbuf_set_data(db, NULL);
2118 VERIFY(arc_buf_remove_ref(buf, db));
2119 dbuf_evict(db);
2120 } else {
2121 VERIFY(!arc_buf_remove_ref(db->db_buf, db));
2122
2123 /*
2124 * A dbuf will be eligible for eviction if either the
2125 * 'primarycache' property is set or a duplicate
2126 * copy of this buffer is already cached in the arc.
2127 *
2128 * In the case of the 'primarycache' a buffer
2129 * is considered for eviction if it matches the
2130 * criteria set in the property.
2131 *
2132 * To decide if our buffer is considered a
2133 * duplicate, we must call into the arc to determine
2134 * if multiple buffers are referencing the same
2135 * block on-disk. If so, then we simply evict
2136 * ourselves.
2137 */
2138 if (!DBUF_IS_CACHEABLE(db)) {
2139 if (db->db_blkptr != NULL &&
2140 !BP_IS_HOLE(db->db_blkptr) &&
2141 !BP_IS_EMBEDDED(db->db_blkptr)) {
2142 spa_t *spa =
2143 dmu_objset_spa(db->db_objset);
2144 blkptr_t bp = *db->db_blkptr;
2145 dbuf_clear(db);
2146 arc_freed(spa, &bp);
2147 } else {
2148 dbuf_clear(db);
2149 }
2150 } else if (arc_buf_eviction_needed(db->db_buf)) {
2151 dbuf_clear(db);
2152 } else {
2153 mutex_exit(&db->db_mtx);
2154 }
2155 }
2156 } else {
2157 mutex_exit(&db->db_mtx);
2158 }
2159}
2160
2161#pragma weak dmu_buf_refcount = dbuf_refcount
2162uint64_t
2163dbuf_refcount(dmu_buf_impl_t *db)
2164{
2165 return (refcount_count(&db->db_holds));
2166}
2167
2168void *
2169dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr,
2170 dmu_buf_evict_func_t *evict_func)
2171{
2172 return (dmu_buf_update_user(db_fake, NULL, user_ptr, evict_func));
2173}
2174
2175void *
2176dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr,
2177 dmu_buf_evict_func_t *evict_func)
2178{
2179 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2180
2181 db->db_immediate_evict = TRUE;
2182 return (dmu_buf_update_user(db_fake, NULL, user_ptr, evict_func));
2183}
2184
2185void *
2186dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr,
2187 dmu_buf_evict_func_t *evict_func)
2188{
2189 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2190 ASSERT(db->db_level == 0);
2191
2192 ASSERT((user_ptr == NULL) == (evict_func == NULL));
2193
2194 mutex_enter(&db->db_mtx);
2195
2196 if (db->db_user_ptr == old_user_ptr) {
2197 db->db_user_ptr = user_ptr;
2198 db->db_evict_func = evict_func;
2199 } else {
2200 old_user_ptr = db->db_user_ptr;
2201 }
2202
2203 mutex_exit(&db->db_mtx);
2204 return (old_user_ptr);
2205}
2206
2207void *
2208dmu_buf_get_user(dmu_buf_t *db_fake)
2209{
2210 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2211 ASSERT(!refcount_is_zero(&db->db_holds));
2212
2213 return (db->db_user_ptr);
2214}
2215
2216boolean_t
2217dmu_buf_freeable(dmu_buf_t *dbuf)
2218{
2219 boolean_t res = B_FALSE;
2220 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
2221
2222 if (db->db_blkptr)
2223 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
2224 db->db_blkptr, db->db_blkptr->blk_birth);
2225
2226 return (res);
2227}
2228
2229blkptr_t *
2230dmu_buf_get_blkptr(dmu_buf_t *db)
2231{
2232 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db;
2233 return (dbi->db_blkptr);
2234}
2235
2236static void
2237dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
2238{
2239 /* ASSERT(dmu_tx_is_syncing(tx) */
2240 ASSERT(MUTEX_HELD(&db->db_mtx));
2241
2242 if (db->db_blkptr != NULL)
2243 return;
2244
2245 if (db->db_blkid == DMU_SPILL_BLKID) {
2246 db->db_blkptr = &dn->dn_phys->dn_spill;
2247 BP_ZERO(db->db_blkptr);
2248 return;
2249 }
2250 if (db->db_level == dn->dn_phys->dn_nlevels-1) {
2251 /*
2252 * This buffer was allocated at a time when there was
2253 * no available blkptrs from the dnode, or it was
2254 * inappropriate to hook it in (i.e., nlevels mis-match).
2255 */
2256 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr);
2257 ASSERT(db->db_parent == NULL);
2258 db->db_parent = dn->dn_dbuf;
2259 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid];
2260 DBUF_VERIFY(db);
2261 } else {
2262 dmu_buf_impl_t *parent = db->db_parent;
2263 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2264
2265 ASSERT(dn->dn_phys->dn_nlevels > 1);
2266 if (parent == NULL) {
2267 mutex_exit(&db->db_mtx);
2268 rw_enter(&dn->dn_struct_rwlock, RW_READER);
2269 (void) dbuf_hold_impl(dn, db->db_level+1,
2270 db->db_blkid >> epbs, FALSE, db, &parent);
2271 rw_exit(&dn->dn_struct_rwlock);
2272 mutex_enter(&db->db_mtx);
2273 db->db_parent = parent;
2274 }
2275 db->db_blkptr = (blkptr_t *)parent->db.db_data +
2276 (db->db_blkid & ((1ULL << epbs) - 1));
2277 DBUF_VERIFY(db);
2278 }
2279}
2280
2281static void
2282dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2283{
2284 dmu_buf_impl_t *db = dr->dr_dbuf;
2285 dnode_t *dn;
2286 zio_t *zio;
2287
2288 ASSERT(dmu_tx_is_syncing(tx));
2289
2290 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2291
2292 mutex_enter(&db->db_mtx);
2293
2294 ASSERT(db->db_level > 0);
2295 DBUF_VERIFY(db);
2296
2297 /* Read the block if it hasn't been read yet. */
2298 if (db->db_buf == NULL) {
2299 mutex_exit(&db->db_mtx);
2300 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
2301 mutex_enter(&db->db_mtx);
2302 }
2303 ASSERT3U(db->db_state, ==, DB_CACHED);
2304 ASSERT(db->db_buf != NULL);
2305
2306 DB_DNODE_ENTER(db);
2307 dn = DB_DNODE(db);
2308 /* Indirect block size must match what the dnode thinks it is. */
2309 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2310 dbuf_check_blkptr(dn, db);
2311 DB_DNODE_EXIT(db);
2312
2313 /* Provide the pending dirty record to child dbufs */
2314 db->db_data_pending = dr;
2315
2316 mutex_exit(&db->db_mtx);
2317 dbuf_write(dr, db->db_buf, tx);
2318
2319 zio = dr->dr_zio;
2320 mutex_enter(&dr->dt.di.dr_mtx);
| 1366 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1367
1368 ASSERT(db->db_dirtycnt > 0);
1369 db->db_dirtycnt -= 1;
1370
1371 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1372 arc_buf_t *buf = db->db_buf;
1373
1374 ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
1375 dbuf_set_data(db, NULL);
1376 VERIFY(arc_buf_remove_ref(buf, db));
1377 dbuf_evict(db);
1378 return (B_TRUE);
1379 }
1380
1381 return (B_FALSE);
1382}
1383
1384void
1385dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx)
1386{
1387 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1388 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1389
1390 ASSERT(tx->tx_txg != 0);
1391 ASSERT(!refcount_is_zero(&db->db_holds));
1392
1393 DB_DNODE_ENTER(db);
1394 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
1395 rf |= DB_RF_HAVESTRUCT;
1396 DB_DNODE_EXIT(db);
1397 (void) dbuf_read(db, NULL, rf);
1398 (void) dbuf_dirty(db, tx);
1399}
1400
1401void
1402dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1403{
1404 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1405
1406 db->db_state = DB_NOFILL;
1407
1408 dmu_buf_will_fill(db_fake, tx);
1409}
1410
1411void
1412dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1413{
1414 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1415
1416 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1417 ASSERT(tx->tx_txg != 0);
1418 ASSERT(db->db_level == 0);
1419 ASSERT(!refcount_is_zero(&db->db_holds));
1420
1421 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1422 dmu_tx_private_ok(tx));
1423
1424 dbuf_noread(db);
1425 (void) dbuf_dirty(db, tx);
1426}
1427
1428#pragma weak dmu_buf_fill_done = dbuf_fill_done
1429/* ARGSUSED */
1430void
1431dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1432{
1433 mutex_enter(&db->db_mtx);
1434 DBUF_VERIFY(db);
1435
1436 if (db->db_state == DB_FILL) {
1437 if (db->db_level == 0 && db->db_freed_in_flight) {
1438 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1439 /* we were freed while filling */
1440 /* XXX dbuf_undirty? */
1441 bzero(db->db.db_data, db->db.db_size);
1442 db->db_freed_in_flight = FALSE;
1443 }
1444 db->db_state = DB_CACHED;
1445 cv_broadcast(&db->db_changed);
1446 }
1447 mutex_exit(&db->db_mtx);
1448}
1449
1450void
1451dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data,
1452 bp_embedded_type_t etype, enum zio_compress comp,
1453 int uncompressed_size, int compressed_size, int byteorder,
1454 dmu_tx_t *tx)
1455{
1456 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
1457 struct dirty_leaf *dl;
1458 dmu_object_type_t type;
1459
1460 DB_DNODE_ENTER(db);
1461 type = DB_DNODE(db)->dn_type;
1462 DB_DNODE_EXIT(db);
1463
1464 ASSERT0(db->db_level);
1465 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1466
1467 dmu_buf_will_not_fill(dbuf, tx);
1468
1469 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
1470 dl = &db->db_last_dirty->dt.dl;
1471 encode_embedded_bp_compressed(&dl->dr_overridden_by,
1472 data, comp, uncompressed_size, compressed_size);
1473 BPE_SET_ETYPE(&dl->dr_overridden_by, etype);
1474 BP_SET_TYPE(&dl->dr_overridden_by, type);
1475 BP_SET_LEVEL(&dl->dr_overridden_by, 0);
1476 BP_SET_BYTEORDER(&dl->dr_overridden_by, byteorder);
1477
1478 dl->dr_override_state = DR_OVERRIDDEN;
1479 dl->dr_overridden_by.blk_birth = db->db_last_dirty->dr_txg;
1480}
1481
1482/*
1483 * Directly assign a provided arc buf to a given dbuf if it's not referenced
1484 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
1485 */
1486void
1487dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
1488{
1489 ASSERT(!refcount_is_zero(&db->db_holds));
1490 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1491 ASSERT(db->db_level == 0);
1492 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
1493 ASSERT(buf != NULL);
1494 ASSERT(arc_buf_size(buf) == db->db.db_size);
1495 ASSERT(tx->tx_txg != 0);
1496
1497 arc_return_buf(buf, db);
1498 ASSERT(arc_released(buf));
1499
1500 mutex_enter(&db->db_mtx);
1501
1502 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1503 cv_wait(&db->db_changed, &db->db_mtx);
1504
1505 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
1506
1507 if (db->db_state == DB_CACHED &&
1508 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
1509 mutex_exit(&db->db_mtx);
1510 (void) dbuf_dirty(db, tx);
1511 bcopy(buf->b_data, db->db.db_data, db->db.db_size);
1512 VERIFY(arc_buf_remove_ref(buf, db));
1513 xuio_stat_wbuf_copied();
1514 return;
1515 }
1516
1517 xuio_stat_wbuf_nocopy();
1518 if (db->db_state == DB_CACHED) {
1519 dbuf_dirty_record_t *dr = db->db_last_dirty;
1520
1521 ASSERT(db->db_buf != NULL);
1522 if (dr != NULL && dr->dr_txg == tx->tx_txg) {
1523 ASSERT(dr->dt.dl.dr_data == db->db_buf);
1524 if (!arc_released(db->db_buf)) {
1525 ASSERT(dr->dt.dl.dr_override_state ==
1526 DR_OVERRIDDEN);
1527 arc_release(db->db_buf, db);
1528 }
1529 dr->dt.dl.dr_data = buf;
1530 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1531 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
1532 arc_release(db->db_buf, db);
1533 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1534 }
1535 db->db_buf = NULL;
1536 }
1537 ASSERT(db->db_buf == NULL);
1538 dbuf_set_data(db, buf);
1539 db->db_state = DB_FILL;
1540 mutex_exit(&db->db_mtx);
1541 (void) dbuf_dirty(db, tx);
1542 dmu_buf_fill_done(&db->db, tx);
1543}
1544
1545/*
1546 * "Clear" the contents of this dbuf. This will mark the dbuf
1547 * EVICTING and clear *most* of its references. Unfortunately,
1548 * when we are not holding the dn_dbufs_mtx, we can't clear the
1549 * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
1550 * in this case. For callers from the DMU we will usually see:
1551 * dbuf_clear()->arc_clear_callback()->dbuf_do_evict()->dbuf_destroy()
1552 * For the arc callback, we will usually see:
1553 * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
1554 * Sometimes, though, we will get a mix of these two:
1555 * DMU: dbuf_clear()->arc_clear_callback()
1556 * ARC: dbuf_do_evict()->dbuf_destroy()
1557 *
1558 * This routine will dissociate the dbuf from the arc, by calling
1559 * arc_clear_callback(), but will not evict the data from the ARC.
1560 */
1561void
1562dbuf_clear(dmu_buf_impl_t *db)
1563{
1564 dnode_t *dn;
1565 dmu_buf_impl_t *parent = db->db_parent;
1566 dmu_buf_impl_t *dndb;
1567 boolean_t dbuf_gone = B_FALSE;
1568
1569 ASSERT(MUTEX_HELD(&db->db_mtx));
1570 ASSERT(refcount_is_zero(&db->db_holds));
1571
1572 dbuf_evict_user(db);
1573
1574 if (db->db_state == DB_CACHED) {
1575 ASSERT(db->db.db_data != NULL);
1576 if (db->db_blkid == DMU_BONUS_BLKID) {
1577 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1578 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1579 }
1580 db->db.db_data = NULL;
1581 db->db_state = DB_UNCACHED;
1582 }
1583
1584 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
1585 ASSERT(db->db_data_pending == NULL);
1586
1587 db->db_state = DB_EVICTING;
1588 db->db_blkptr = NULL;
1589
1590 DB_DNODE_ENTER(db);
1591 dn = DB_DNODE(db);
1592 dndb = dn->dn_dbuf;
1593 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1594 avl_remove(&dn->dn_dbufs, db);
1595 atomic_dec_32(&dn->dn_dbufs_count);
1596 membar_producer();
1597 DB_DNODE_EXIT(db);
1598 /*
1599 * Decrementing the dbuf count means that the hold corresponding
1600 * to the removed dbuf is no longer discounted in dnode_move(),
1601 * so the dnode cannot be moved until after we release the hold.
1602 * The membar_producer() ensures visibility of the decremented
1603 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually
1604 * release any lock.
1605 */
1606 dnode_rele(dn, db);
1607 db->db_dnode_handle = NULL;
1608 } else {
1609 DB_DNODE_EXIT(db);
1610 }
1611
1612 if (db->db_buf)
1613 dbuf_gone = arc_clear_callback(db->db_buf);
1614
1615 if (!dbuf_gone)
1616 mutex_exit(&db->db_mtx);
1617
1618 /*
1619 * If this dbuf is referenced from an indirect dbuf,
1620 * decrement the ref count on the indirect dbuf.
1621 */
1622 if (parent && parent != dndb)
1623 dbuf_rele(parent, db);
1624}
1625
1626static int
1627dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1628 dmu_buf_impl_t **parentp, blkptr_t **bpp)
1629{
1630 int nlevels, epbs;
1631
1632 *parentp = NULL;
1633 *bpp = NULL;
1634
1635 ASSERT(blkid != DMU_BONUS_BLKID);
1636
1637 if (blkid == DMU_SPILL_BLKID) {
1638 mutex_enter(&dn->dn_mtx);
1639 if (dn->dn_have_spill &&
1640 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
1641 *bpp = &dn->dn_phys->dn_spill;
1642 else
1643 *bpp = NULL;
1644 dbuf_add_ref(dn->dn_dbuf, NULL);
1645 *parentp = dn->dn_dbuf;
1646 mutex_exit(&dn->dn_mtx);
1647 return (0);
1648 }
1649
1650 if (dn->dn_phys->dn_nlevels == 0)
1651 nlevels = 1;
1652 else
1653 nlevels = dn->dn_phys->dn_nlevels;
1654
1655 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1656
1657 ASSERT3U(level * epbs, <, 64);
1658 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1659 if (level >= nlevels ||
1660 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
1661 /* the buffer has no parent yet */
1662 return (SET_ERROR(ENOENT));
1663 } else if (level < nlevels-1) {
1664 /* this block is referenced from an indirect block */
1665 int err = dbuf_hold_impl(dn, level+1,
1666 blkid >> epbs, fail_sparse, NULL, parentp);
1667 if (err)
1668 return (err);
1669 err = dbuf_read(*parentp, NULL,
1670 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1671 if (err) {
1672 dbuf_rele(*parentp, NULL);
1673 *parentp = NULL;
1674 return (err);
1675 }
1676 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1677 (blkid & ((1ULL << epbs) - 1));
1678 return (0);
1679 } else {
1680 /* the block is referenced from the dnode */
1681 ASSERT3U(level, ==, nlevels-1);
1682 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1683 blkid < dn->dn_phys->dn_nblkptr);
1684 if (dn->dn_dbuf) {
1685 dbuf_add_ref(dn->dn_dbuf, NULL);
1686 *parentp = dn->dn_dbuf;
1687 }
1688 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1689 return (0);
1690 }
1691}
1692
1693static dmu_buf_impl_t *
1694dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1695 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1696{
1697 objset_t *os = dn->dn_objset;
1698 dmu_buf_impl_t *db, *odb;
1699
1700 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1701 ASSERT(dn->dn_type != DMU_OT_NONE);
1702
1703 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP);
1704
1705 db->db_objset = os;
1706 db->db.db_object = dn->dn_object;
1707 db->db_level = level;
1708 db->db_blkid = blkid;
1709 db->db_last_dirty = NULL;
1710 db->db_dirtycnt = 0;
1711 db->db_dnode_handle = dn->dn_handle;
1712 db->db_parent = parent;
1713 db->db_blkptr = blkptr;
1714
1715 db->db_user_ptr = NULL;
1716 db->db_evict_func = NULL;
1717 db->db_immediate_evict = 0;
1718 db->db_freed_in_flight = 0;
1719
1720 if (blkid == DMU_BONUS_BLKID) {
1721 ASSERT3P(parent, ==, dn->dn_dbuf);
1722 db->db.db_size = DN_MAX_BONUSLEN -
1723 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1724 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1725 db->db.db_offset = DMU_BONUS_BLKID;
1726 db->db_state = DB_UNCACHED;
1727 /* the bonus dbuf is not placed in the hash table */
1728 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1729 return (db);
1730 } else if (blkid == DMU_SPILL_BLKID) {
1731 db->db.db_size = (blkptr != NULL) ?
1732 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE;
1733 db->db.db_offset = 0;
1734 } else {
1735 int blocksize =
1736 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz;
1737 db->db.db_size = blocksize;
1738 db->db.db_offset = db->db_blkid * blocksize;
1739 }
1740
1741 /*
1742 * Hold the dn_dbufs_mtx while we get the new dbuf
1743 * in the hash table *and* added to the dbufs list.
1744 * This prevents a possible deadlock with someone
1745 * trying to look up this dbuf before its added to the
1746 * dn_dbufs list.
1747 */
1748 mutex_enter(&dn->dn_dbufs_mtx);
1749 db->db_state = DB_EVICTING;
1750 if ((odb = dbuf_hash_insert(db)) != NULL) {
1751 /* someone else inserted it first */
1752 kmem_cache_free(dbuf_cache, db);
1753 mutex_exit(&dn->dn_dbufs_mtx);
1754 return (odb);
1755 }
1756 avl_add(&dn->dn_dbufs, db);
1757 if (db->db_level == 0 && db->db_blkid >=
1758 dn->dn_unlisted_l0_blkid)
1759 dn->dn_unlisted_l0_blkid = db->db_blkid + 1;
1760 db->db_state = DB_UNCACHED;
1761 mutex_exit(&dn->dn_dbufs_mtx);
1762 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1763
1764 if (parent && parent != dn->dn_dbuf)
1765 dbuf_add_ref(parent, db);
1766
1767 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1768 refcount_count(&dn->dn_holds) > 0);
1769 (void) refcount_add(&dn->dn_holds, db);
1770 atomic_inc_32(&dn->dn_dbufs_count);
1771
1772 dprintf_dbuf(db, "db=%p\n", db);
1773
1774 return (db);
1775}
1776
1777static int
1778dbuf_do_evict(void *private)
1779{
1780 dmu_buf_impl_t *db = private;
1781
1782 if (!MUTEX_HELD(&db->db_mtx))
1783 mutex_enter(&db->db_mtx);
1784
1785 ASSERT(refcount_is_zero(&db->db_holds));
1786
1787 if (db->db_state != DB_EVICTING) {
1788 ASSERT(db->db_state == DB_CACHED);
1789 DBUF_VERIFY(db);
1790 db->db_buf = NULL;
1791 dbuf_evict(db);
1792 } else {
1793 mutex_exit(&db->db_mtx);
1794 dbuf_destroy(db);
1795 }
1796 return (0);
1797}
1798
1799static void
1800dbuf_destroy(dmu_buf_impl_t *db)
1801{
1802 ASSERT(refcount_is_zero(&db->db_holds));
1803
1804 if (db->db_blkid != DMU_BONUS_BLKID) {
1805 /*
1806 * If this dbuf is still on the dn_dbufs list,
1807 * remove it from that list.
1808 */
1809 if (db->db_dnode_handle != NULL) {
1810 dnode_t *dn;
1811
1812 DB_DNODE_ENTER(db);
1813 dn = DB_DNODE(db);
1814 mutex_enter(&dn->dn_dbufs_mtx);
1815 avl_remove(&dn->dn_dbufs, db);
1816 atomic_dec_32(&dn->dn_dbufs_count);
1817 mutex_exit(&dn->dn_dbufs_mtx);
1818 DB_DNODE_EXIT(db);
1819 /*
1820 * Decrementing the dbuf count means that the hold
1821 * corresponding to the removed dbuf is no longer
1822 * discounted in dnode_move(), so the dnode cannot be
1823 * moved until after we release the hold.
1824 */
1825 dnode_rele(dn, db);
1826 db->db_dnode_handle = NULL;
1827 }
1828 dbuf_hash_remove(db);
1829 }
1830 db->db_parent = NULL;
1831 db->db_buf = NULL;
1832
1833 ASSERT(db->db.db_data == NULL);
1834 ASSERT(db->db_hash_next == NULL);
1835 ASSERT(db->db_blkptr == NULL);
1836 ASSERT(db->db_data_pending == NULL);
1837
1838 kmem_cache_free(dbuf_cache, db);
1839 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1840}
1841
1842void
1843dbuf_prefetch(dnode_t *dn, uint64_t blkid, zio_priority_t prio)
1844{
1845 dmu_buf_impl_t *db = NULL;
1846 blkptr_t *bp = NULL;
1847
1848 ASSERT(blkid != DMU_BONUS_BLKID);
1849 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1850
1851 if (dnode_block_freed(dn, blkid))
1852 return;
1853
1854 /* dbuf_find() returns with db_mtx held */
1855 if (db = dbuf_find(dn, 0, blkid)) {
1856 /*
1857 * This dbuf is already in the cache. We assume that
1858 * it is already CACHED, or else about to be either
1859 * read or filled.
1860 */
1861 mutex_exit(&db->db_mtx);
1862 return;
1863 }
1864
1865 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) {
1866 if (bp && !BP_IS_HOLE(bp) && !BP_IS_EMBEDDED(bp)) {
1867 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
1868 arc_flags_t aflags =
1869 ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
1870 zbookmark_phys_t zb;
1871
1872 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1873 dn->dn_object, 0, blkid);
1874
1875 (void) arc_read(NULL, dn->dn_objset->os_spa,
1876 bp, NULL, NULL, prio,
1877 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1878 &aflags, &zb);
1879 }
1880 if (db)
1881 dbuf_rele(db, NULL);
1882 }
1883}
1884
1885/*
1886 * Returns with db_holds incremented, and db_mtx not held.
1887 * Note: dn_struct_rwlock must be held.
1888 */
1889int
1890dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
1891 void *tag, dmu_buf_impl_t **dbp)
1892{
1893 dmu_buf_impl_t *db, *parent = NULL;
1894
1895 ASSERT(blkid != DMU_BONUS_BLKID);
1896 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1897 ASSERT3U(dn->dn_nlevels, >, level);
1898
1899 *dbp = NULL;
1900top:
1901 /* dbuf_find() returns with db_mtx held */
1902 db = dbuf_find(dn, level, blkid);
1903
1904 if (db == NULL) {
1905 blkptr_t *bp = NULL;
1906 int err;
1907
1908 ASSERT3P(parent, ==, NULL);
1909 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp);
1910 if (fail_sparse) {
1911 if (err == 0 && bp && BP_IS_HOLE(bp))
1912 err = SET_ERROR(ENOENT);
1913 if (err) {
1914 if (parent)
1915 dbuf_rele(parent, NULL);
1916 return (err);
1917 }
1918 }
1919 if (err && err != ENOENT)
1920 return (err);
1921 db = dbuf_create(dn, level, blkid, parent, bp);
1922 }
1923
1924 if (db->db_buf && refcount_is_zero(&db->db_holds)) {
1925 arc_buf_add_ref(db->db_buf, db);
1926 if (db->db_buf->b_data == NULL) {
1927 dbuf_clear(db);
1928 if (parent) {
1929 dbuf_rele(parent, NULL);
1930 parent = NULL;
1931 }
1932 goto top;
1933 }
1934 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data);
1935 }
1936
1937 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf));
1938
1939 /*
1940 * If this buffer is currently syncing out, and we are are
1941 * still referencing it from db_data, we need to make a copy
1942 * of it in case we decide we want to dirty it again in this txg.
1943 */
1944 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1945 dn->dn_object != DMU_META_DNODE_OBJECT &&
1946 db->db_state == DB_CACHED && db->db_data_pending) {
1947 dbuf_dirty_record_t *dr = db->db_data_pending;
1948
1949 if (dr->dt.dl.dr_data == db->db_buf) {
1950 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
1951
1952 dbuf_set_data(db,
1953 arc_buf_alloc(dn->dn_objset->os_spa,
1954 db->db.db_size, db, type));
1955 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data,
1956 db->db.db_size);
1957 }
1958 }
1959
1960 (void) refcount_add(&db->db_holds, tag);
1961 DBUF_VERIFY(db);
1962 mutex_exit(&db->db_mtx);
1963
1964 /* NOTE: we can't rele the parent until after we drop the db_mtx */
1965 if (parent)
1966 dbuf_rele(parent, NULL);
1967
1968 ASSERT3P(DB_DNODE(db), ==, dn);
1969 ASSERT3U(db->db_blkid, ==, blkid);
1970 ASSERT3U(db->db_level, ==, level);
1971 *dbp = db;
1972
1973 return (0);
1974}
1975
1976dmu_buf_impl_t *
1977dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
1978{
1979 dmu_buf_impl_t *db;
1980 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
1981 return (err ? NULL : db);
1982}
1983
1984dmu_buf_impl_t *
1985dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
1986{
1987 dmu_buf_impl_t *db;
1988 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
1989 return (err ? NULL : db);
1990}
1991
1992void
1993dbuf_create_bonus(dnode_t *dn)
1994{
1995 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
1996
1997 ASSERT(dn->dn_bonus == NULL);
1998 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL);
1999}
2000
2001int
2002dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx)
2003{
2004 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2005 dnode_t *dn;
2006
2007 if (db->db_blkid != DMU_SPILL_BLKID)
2008 return (SET_ERROR(ENOTSUP));
2009 if (blksz == 0)
2010 blksz = SPA_MINBLOCKSIZE;
2011 ASSERT3U(blksz, <=, spa_maxblocksize(dmu_objset_spa(db->db_objset)));
2012 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE);
2013
2014 DB_DNODE_ENTER(db);
2015 dn = DB_DNODE(db);
2016 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
2017 dbuf_new_size(db, blksz, tx);
2018 rw_exit(&dn->dn_struct_rwlock);
2019 DB_DNODE_EXIT(db);
2020
2021 return (0);
2022}
2023
2024void
2025dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx)
2026{
2027 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx);
2028}
2029
2030#pragma weak dmu_buf_add_ref = dbuf_add_ref
2031void
2032dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
2033{
2034 int64_t holds = refcount_add(&db->db_holds, tag);
2035 ASSERT(holds > 1);
2036}
2037
2038/*
2039 * If you call dbuf_rele() you had better not be referencing the dnode handle
2040 * unless you have some other direct or indirect hold on the dnode. (An indirect
2041 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.)
2042 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the
2043 * dnode's parent dbuf evicting its dnode handles.
2044 */
2045void
2046dbuf_rele(dmu_buf_impl_t *db, void *tag)
2047{
2048 mutex_enter(&db->db_mtx);
2049 dbuf_rele_and_unlock(db, tag);
2050}
2051
2052void
2053dmu_buf_rele(dmu_buf_t *db, void *tag)
2054{
2055 dbuf_rele((dmu_buf_impl_t *)db, tag);
2056}
2057
2058/*
2059 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
2060 * db_dirtycnt and db_holds to be updated atomically.
2061 */
2062void
2063dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
2064{
2065 int64_t holds;
2066
2067 ASSERT(MUTEX_HELD(&db->db_mtx));
2068 DBUF_VERIFY(db);
2069
2070 /*
2071 * Remove the reference to the dbuf before removing its hold on the
2072 * dnode so we can guarantee in dnode_move() that a referenced bonus
2073 * buffer has a corresponding dnode hold.
2074 */
2075 holds = refcount_remove(&db->db_holds, tag);
2076 ASSERT(holds >= 0);
2077
2078 /*
2079 * We can't freeze indirects if there is a possibility that they
2080 * may be modified in the current syncing context.
2081 */
2082 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
2083 arc_buf_freeze(db->db_buf);
2084
2085 if (holds == db->db_dirtycnt &&
2086 db->db_level == 0 && db->db_immediate_evict)
2087 dbuf_evict_user(db);
2088
2089 if (holds == 0) {
2090 if (db->db_blkid == DMU_BONUS_BLKID) {
2091 mutex_exit(&db->db_mtx);
2092
2093 /*
2094 * If the dnode moves here, we cannot cross this barrier
2095 * until the move completes.
2096 */
2097 DB_DNODE_ENTER(db);
2098 atomic_dec_32(&DB_DNODE(db)->dn_dbufs_count);
2099 DB_DNODE_EXIT(db);
2100 /*
2101 * The bonus buffer's dnode hold is no longer discounted
2102 * in dnode_move(). The dnode cannot move until after
2103 * the dnode_rele().
2104 */
2105 dnode_rele(DB_DNODE(db), db);
2106 } else if (db->db_buf == NULL) {
2107 /*
2108 * This is a special case: we never associated this
2109 * dbuf with any data allocated from the ARC.
2110 */
2111 ASSERT(db->db_state == DB_UNCACHED ||
2112 db->db_state == DB_NOFILL);
2113 dbuf_evict(db);
2114 } else if (arc_released(db->db_buf)) {
2115 arc_buf_t *buf = db->db_buf;
2116 /*
2117 * This dbuf has anonymous data associated with it.
2118 */
2119 dbuf_set_data(db, NULL);
2120 VERIFY(arc_buf_remove_ref(buf, db));
2121 dbuf_evict(db);
2122 } else {
2123 VERIFY(!arc_buf_remove_ref(db->db_buf, db));
2124
2125 /*
2126 * A dbuf will be eligible for eviction if either the
2127 * 'primarycache' property is set or a duplicate
2128 * copy of this buffer is already cached in the arc.
2129 *
2130 * In the case of the 'primarycache' a buffer
2131 * is considered for eviction if it matches the
2132 * criteria set in the property.
2133 *
2134 * To decide if our buffer is considered a
2135 * duplicate, we must call into the arc to determine
2136 * if multiple buffers are referencing the same
2137 * block on-disk. If so, then we simply evict
2138 * ourselves.
2139 */
2140 if (!DBUF_IS_CACHEABLE(db)) {
2141 if (db->db_blkptr != NULL &&
2142 !BP_IS_HOLE(db->db_blkptr) &&
2143 !BP_IS_EMBEDDED(db->db_blkptr)) {
2144 spa_t *spa =
2145 dmu_objset_spa(db->db_objset);
2146 blkptr_t bp = *db->db_blkptr;
2147 dbuf_clear(db);
2148 arc_freed(spa, &bp);
2149 } else {
2150 dbuf_clear(db);
2151 }
2152 } else if (arc_buf_eviction_needed(db->db_buf)) {
2153 dbuf_clear(db);
2154 } else {
2155 mutex_exit(&db->db_mtx);
2156 }
2157 }
2158 } else {
2159 mutex_exit(&db->db_mtx);
2160 }
2161}
2162
2163#pragma weak dmu_buf_refcount = dbuf_refcount
2164uint64_t
2165dbuf_refcount(dmu_buf_impl_t *db)
2166{
2167 return (refcount_count(&db->db_holds));
2168}
2169
2170void *
2171dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr,
2172 dmu_buf_evict_func_t *evict_func)
2173{
2174 return (dmu_buf_update_user(db_fake, NULL, user_ptr, evict_func));
2175}
2176
2177void *
2178dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr,
2179 dmu_buf_evict_func_t *evict_func)
2180{
2181 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2182
2183 db->db_immediate_evict = TRUE;
2184 return (dmu_buf_update_user(db_fake, NULL, user_ptr, evict_func));
2185}
2186
2187void *
2188dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr,
2189 dmu_buf_evict_func_t *evict_func)
2190{
2191 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2192 ASSERT(db->db_level == 0);
2193
2194 ASSERT((user_ptr == NULL) == (evict_func == NULL));
2195
2196 mutex_enter(&db->db_mtx);
2197
2198 if (db->db_user_ptr == old_user_ptr) {
2199 db->db_user_ptr = user_ptr;
2200 db->db_evict_func = evict_func;
2201 } else {
2202 old_user_ptr = db->db_user_ptr;
2203 }
2204
2205 mutex_exit(&db->db_mtx);
2206 return (old_user_ptr);
2207}
2208
2209void *
2210dmu_buf_get_user(dmu_buf_t *db_fake)
2211{
2212 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2213 ASSERT(!refcount_is_zero(&db->db_holds));
2214
2215 return (db->db_user_ptr);
2216}
2217
2218boolean_t
2219dmu_buf_freeable(dmu_buf_t *dbuf)
2220{
2221 boolean_t res = B_FALSE;
2222 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
2223
2224 if (db->db_blkptr)
2225 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
2226 db->db_blkptr, db->db_blkptr->blk_birth);
2227
2228 return (res);
2229}
2230
2231blkptr_t *
2232dmu_buf_get_blkptr(dmu_buf_t *db)
2233{
2234 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db;
2235 return (dbi->db_blkptr);
2236}
2237
2238static void
2239dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
2240{
2241 /* ASSERT(dmu_tx_is_syncing(tx) */
2242 ASSERT(MUTEX_HELD(&db->db_mtx));
2243
2244 if (db->db_blkptr != NULL)
2245 return;
2246
2247 if (db->db_blkid == DMU_SPILL_BLKID) {
2248 db->db_blkptr = &dn->dn_phys->dn_spill;
2249 BP_ZERO(db->db_blkptr);
2250 return;
2251 }
2252 if (db->db_level == dn->dn_phys->dn_nlevels-1) {
2253 /*
2254 * This buffer was allocated at a time when there was
2255 * no available blkptrs from the dnode, or it was
2256 * inappropriate to hook it in (i.e., nlevels mis-match).
2257 */
2258 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr);
2259 ASSERT(db->db_parent == NULL);
2260 db->db_parent = dn->dn_dbuf;
2261 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid];
2262 DBUF_VERIFY(db);
2263 } else {
2264 dmu_buf_impl_t *parent = db->db_parent;
2265 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2266
2267 ASSERT(dn->dn_phys->dn_nlevels > 1);
2268 if (parent == NULL) {
2269 mutex_exit(&db->db_mtx);
2270 rw_enter(&dn->dn_struct_rwlock, RW_READER);
2271 (void) dbuf_hold_impl(dn, db->db_level+1,
2272 db->db_blkid >> epbs, FALSE, db, &parent);
2273 rw_exit(&dn->dn_struct_rwlock);
2274 mutex_enter(&db->db_mtx);
2275 db->db_parent = parent;
2276 }
2277 db->db_blkptr = (blkptr_t *)parent->db.db_data +
2278 (db->db_blkid & ((1ULL << epbs) - 1));
2279 DBUF_VERIFY(db);
2280 }
2281}
2282
2283static void
2284dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2285{
2286 dmu_buf_impl_t *db = dr->dr_dbuf;
2287 dnode_t *dn;
2288 zio_t *zio;
2289
2290 ASSERT(dmu_tx_is_syncing(tx));
2291
2292 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2293
2294 mutex_enter(&db->db_mtx);
2295
2296 ASSERT(db->db_level > 0);
2297 DBUF_VERIFY(db);
2298
2299 /* Read the block if it hasn't been read yet. */
2300 if (db->db_buf == NULL) {
2301 mutex_exit(&db->db_mtx);
2302 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
2303 mutex_enter(&db->db_mtx);
2304 }
2305 ASSERT3U(db->db_state, ==, DB_CACHED);
2306 ASSERT(db->db_buf != NULL);
2307
2308 DB_DNODE_ENTER(db);
2309 dn = DB_DNODE(db);
2310 /* Indirect block size must match what the dnode thinks it is. */
2311 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2312 dbuf_check_blkptr(dn, db);
2313 DB_DNODE_EXIT(db);
2314
2315 /* Provide the pending dirty record to child dbufs */
2316 db->db_data_pending = dr;
2317
2318 mutex_exit(&db->db_mtx);
2319 dbuf_write(dr, db->db_buf, tx);
2320
2321 zio = dr->dr_zio;
2322 mutex_enter(&dr->dt.di.dr_mtx);
|
2321 dbuf_sync_list(&dr->dt.di.dr_children, tx);
| 2323 dbuf_sync_list(&dr->dt.di.dr_children, db->db_level - 1, tx);
|
2322 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2323 mutex_exit(&dr->dt.di.dr_mtx);
2324 zio_nowait(zio);
2325}
2326
2327static void
2328dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2329{
2330 arc_buf_t **datap = &dr->dt.dl.dr_data;
2331 dmu_buf_impl_t *db = dr->dr_dbuf;
2332 dnode_t *dn;
2333 objset_t *os;
2334 uint64_t txg = tx->tx_txg;
2335
2336 ASSERT(dmu_tx_is_syncing(tx));
2337
2338 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2339
2340 mutex_enter(&db->db_mtx);
2341 /*
2342 * To be synced, we must be dirtied. But we
2343 * might have been freed after the dirty.
2344 */
2345 if (db->db_state == DB_UNCACHED) {
2346 /* This buffer has been freed since it was dirtied */
2347 ASSERT(db->db.db_data == NULL);
2348 } else if (db->db_state == DB_FILL) {
2349 /* This buffer was freed and is now being re-filled */
2350 ASSERT(db->db.db_data != dr->dt.dl.dr_data);
2351 } else {
2352 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL);
2353 }
2354 DBUF_VERIFY(db);
2355
2356 DB_DNODE_ENTER(db);
2357 dn = DB_DNODE(db);
2358
2359 if (db->db_blkid == DMU_SPILL_BLKID) {
2360 mutex_enter(&dn->dn_mtx);
2361 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR;
2362 mutex_exit(&dn->dn_mtx);
2363 }
2364
2365 /*
2366 * If this is a bonus buffer, simply copy the bonus data into the
2367 * dnode. It will be written out when the dnode is synced (and it
2368 * will be synced, since it must have been dirty for dbuf_sync to
2369 * be called).
2370 */
2371 if (db->db_blkid == DMU_BONUS_BLKID) {
2372 dbuf_dirty_record_t **drp;
2373
2374 ASSERT(*datap != NULL);
2375 ASSERT0(db->db_level);
2376 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
2377 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
2378 DB_DNODE_EXIT(db);
2379
2380 if (*datap != db->db.db_data) {
2381 zio_buf_free(*datap, DN_MAX_BONUSLEN);
2382 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
2383 }
2384 db->db_data_pending = NULL;
2385 drp = &db->db_last_dirty;
2386 while (*drp != dr)
2387 drp = &(*drp)->dr_next;
2388 ASSERT(dr->dr_next == NULL);
2389 ASSERT(dr->dr_dbuf == db);
2390 *drp = dr->dr_next;
2391 if (dr->dr_dbuf->db_level != 0) {
2392 list_destroy(&dr->dt.di.dr_children);
2393 mutex_destroy(&dr->dt.di.dr_mtx);
2394 }
2395 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2396 ASSERT(db->db_dirtycnt > 0);
2397 db->db_dirtycnt -= 1;
2398 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2399 return;
2400 }
2401
2402 os = dn->dn_objset;
2403
2404 /*
2405 * This function may have dropped the db_mtx lock allowing a dmu_sync
2406 * operation to sneak in. As a result, we need to ensure that we
2407 * don't check the dr_override_state until we have returned from
2408 * dbuf_check_blkptr.
2409 */
2410 dbuf_check_blkptr(dn, db);
2411
2412 /*
2413 * If this buffer is in the middle of an immediate write,
2414 * wait for the synchronous IO to complete.
2415 */
2416 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
2417 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
2418 cv_wait(&db->db_changed, &db->db_mtx);
2419 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
2420 }
2421
2422 if (db->db_state != DB_NOFILL &&
2423 dn->dn_object != DMU_META_DNODE_OBJECT &&
2424 refcount_count(&db->db_holds) > 1 &&
2425 dr->dt.dl.dr_override_state != DR_OVERRIDDEN &&
2426 *datap == db->db_buf) {
2427 /*
2428 * If this buffer is currently "in use" (i.e., there
2429 * are active holds and db_data still references it),
2430 * then make a copy before we start the write so that
2431 * any modifications from the open txg will not leak
2432 * into this write.
2433 *
2434 * NOTE: this copy does not need to be made for
2435 * objects only modified in the syncing context (e.g.
2436 * DNONE_DNODE blocks).
2437 */
2438 int blksz = arc_buf_size(*datap);
2439 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2440 *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
2441 bcopy(db->db.db_data, (*datap)->b_data, blksz);
2442 }
2443 db->db_data_pending = dr;
2444
2445 mutex_exit(&db->db_mtx);
2446
2447 dbuf_write(dr, *datap, tx);
2448
2449 ASSERT(!list_link_active(&dr->dr_dirty_node));
2450 if (dn->dn_object == DMU_META_DNODE_OBJECT) {
2451 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr);
2452 DB_DNODE_EXIT(db);
2453 } else {
2454 /*
2455 * Although zio_nowait() does not "wait for an IO", it does
2456 * initiate the IO. If this is an empty write it seems plausible
2457 * that the IO could actually be completed before the nowait
2458 * returns. We need to DB_DNODE_EXIT() first in case
2459 * zio_nowait() invalidates the dbuf.
2460 */
2461 DB_DNODE_EXIT(db);
2462 zio_nowait(dr->dr_zio);
2463 }
2464}
2465
2466void
| 2324 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2325 mutex_exit(&dr->dt.di.dr_mtx);
2326 zio_nowait(zio);
2327}
2328
2329static void
2330dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2331{
2332 arc_buf_t **datap = &dr->dt.dl.dr_data;
2333 dmu_buf_impl_t *db = dr->dr_dbuf;
2334 dnode_t *dn;
2335 objset_t *os;
2336 uint64_t txg = tx->tx_txg;
2337
2338 ASSERT(dmu_tx_is_syncing(tx));
2339
2340 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2341
2342 mutex_enter(&db->db_mtx);
2343 /*
2344 * To be synced, we must be dirtied. But we
2345 * might have been freed after the dirty.
2346 */
2347 if (db->db_state == DB_UNCACHED) {
2348 /* This buffer has been freed since it was dirtied */
2349 ASSERT(db->db.db_data == NULL);
2350 } else if (db->db_state == DB_FILL) {
2351 /* This buffer was freed and is now being re-filled */
2352 ASSERT(db->db.db_data != dr->dt.dl.dr_data);
2353 } else {
2354 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL);
2355 }
2356 DBUF_VERIFY(db);
2357
2358 DB_DNODE_ENTER(db);
2359 dn = DB_DNODE(db);
2360
2361 if (db->db_blkid == DMU_SPILL_BLKID) {
2362 mutex_enter(&dn->dn_mtx);
2363 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR;
2364 mutex_exit(&dn->dn_mtx);
2365 }
2366
2367 /*
2368 * If this is a bonus buffer, simply copy the bonus data into the
2369 * dnode. It will be written out when the dnode is synced (and it
2370 * will be synced, since it must have been dirty for dbuf_sync to
2371 * be called).
2372 */
2373 if (db->db_blkid == DMU_BONUS_BLKID) {
2374 dbuf_dirty_record_t **drp;
2375
2376 ASSERT(*datap != NULL);
2377 ASSERT0(db->db_level);
2378 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
2379 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
2380 DB_DNODE_EXIT(db);
2381
2382 if (*datap != db->db.db_data) {
2383 zio_buf_free(*datap, DN_MAX_BONUSLEN);
2384 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
2385 }
2386 db->db_data_pending = NULL;
2387 drp = &db->db_last_dirty;
2388 while (*drp != dr)
2389 drp = &(*drp)->dr_next;
2390 ASSERT(dr->dr_next == NULL);
2391 ASSERT(dr->dr_dbuf == db);
2392 *drp = dr->dr_next;
2393 if (dr->dr_dbuf->db_level != 0) {
2394 list_destroy(&dr->dt.di.dr_children);
2395 mutex_destroy(&dr->dt.di.dr_mtx);
2396 }
2397 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2398 ASSERT(db->db_dirtycnt > 0);
2399 db->db_dirtycnt -= 1;
2400 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2401 return;
2402 }
2403
2404 os = dn->dn_objset;
2405
2406 /*
2407 * This function may have dropped the db_mtx lock allowing a dmu_sync
2408 * operation to sneak in. As a result, we need to ensure that we
2409 * don't check the dr_override_state until we have returned from
2410 * dbuf_check_blkptr.
2411 */
2412 dbuf_check_blkptr(dn, db);
2413
2414 /*
2415 * If this buffer is in the middle of an immediate write,
2416 * wait for the synchronous IO to complete.
2417 */
2418 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
2419 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
2420 cv_wait(&db->db_changed, &db->db_mtx);
2421 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
2422 }
2423
2424 if (db->db_state != DB_NOFILL &&
2425 dn->dn_object != DMU_META_DNODE_OBJECT &&
2426 refcount_count(&db->db_holds) > 1 &&
2427 dr->dt.dl.dr_override_state != DR_OVERRIDDEN &&
2428 *datap == db->db_buf) {
2429 /*
2430 * If this buffer is currently "in use" (i.e., there
2431 * are active holds and db_data still references it),
2432 * then make a copy before we start the write so that
2433 * any modifications from the open txg will not leak
2434 * into this write.
2435 *
2436 * NOTE: this copy does not need to be made for
2437 * objects only modified in the syncing context (e.g.
2438 * DNONE_DNODE blocks).
2439 */
2440 int blksz = arc_buf_size(*datap);
2441 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2442 *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
2443 bcopy(db->db.db_data, (*datap)->b_data, blksz);
2444 }
2445 db->db_data_pending = dr;
2446
2447 mutex_exit(&db->db_mtx);
2448
2449 dbuf_write(dr, *datap, tx);
2450
2451 ASSERT(!list_link_active(&dr->dr_dirty_node));
2452 if (dn->dn_object == DMU_META_DNODE_OBJECT) {
2453 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr);
2454 DB_DNODE_EXIT(db);
2455 } else {
2456 /*
2457 * Although zio_nowait() does not "wait for an IO", it does
2458 * initiate the IO. If this is an empty write it seems plausible
2459 * that the IO could actually be completed before the nowait
2460 * returns. We need to DB_DNODE_EXIT() first in case
2461 * zio_nowait() invalidates the dbuf.
2462 */
2463 DB_DNODE_EXIT(db);
2464 zio_nowait(dr->dr_zio);
2465 }
2466}
2467
2468void
|
2467dbuf_sync_list(list_t *list, dmu_tx_t *tx)
| 2469dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx)
|
2468{
2469 dbuf_dirty_record_t *dr;
2470
2471 while (dr = list_head(list)) {
2472 if (dr->dr_zio != NULL) {
2473 /*
2474 * If we find an already initialized zio then we
2475 * are processing the meta-dnode, and we have finished.
2476 * The dbufs for all dnodes are put back on the list
2477 * during processing, so that we can zio_wait()
2478 * these IOs after initiating all child IOs.
2479 */
2480 ASSERT3U(dr->dr_dbuf->db.db_object, ==,
2481 DMU_META_DNODE_OBJECT);
2482 break;
2483 }
| 2470{
2471 dbuf_dirty_record_t *dr;
2472
2473 while (dr = list_head(list)) {
2474 if (dr->dr_zio != NULL) {
2475 /*
2476 * If we find an already initialized zio then we
2477 * are processing the meta-dnode, and we have finished.
2478 * The dbufs for all dnodes are put back on the list
2479 * during processing, so that we can zio_wait()
2480 * these IOs after initiating all child IOs.
2481 */
2482 ASSERT3U(dr->dr_dbuf->db.db_object, ==,
2483 DMU_META_DNODE_OBJECT);
2484 break;
2485 }
|
| 2486 if (dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID &&
2487 dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) {
2488 VERIFY3U(dr->dr_dbuf->db_level, ==, level);
2489 }
|
2484 list_remove(list, dr);
2485 if (dr->dr_dbuf->db_level > 0)
2486 dbuf_sync_indirect(dr, tx);
2487 else
2488 dbuf_sync_leaf(dr, tx);
2489 }
2490}
2491
2492/* ARGSUSED */
2493static void
2494dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
2495{
2496 dmu_buf_impl_t *db = vdb;
2497 dnode_t *dn;
2498 blkptr_t *bp = zio->io_bp;
2499 blkptr_t *bp_orig = &zio->io_bp_orig;
2500 spa_t *spa = zio->io_spa;
2501 int64_t delta;
2502 uint64_t fill = 0;
2503 int i;
2504
2505 ASSERT3P(db->db_blkptr, ==, bp);
2506
2507 DB_DNODE_ENTER(db);
2508 dn = DB_DNODE(db);
2509 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig);
2510 dnode_diduse_space(dn, delta - zio->io_prev_space_delta);
2511 zio->io_prev_space_delta = delta;
2512
2513 if (bp->blk_birth != 0) {
2514 ASSERT((db->db_blkid != DMU_SPILL_BLKID &&
2515 BP_GET_TYPE(bp) == dn->dn_type) ||
2516 (db->db_blkid == DMU_SPILL_BLKID &&
2517 BP_GET_TYPE(bp) == dn->dn_bonustype) ||
2518 BP_IS_EMBEDDED(bp));
2519 ASSERT(BP_GET_LEVEL(bp) == db->db_level);
2520 }
2521
2522 mutex_enter(&db->db_mtx);
2523
2524#ifdef ZFS_DEBUG
2525 if (db->db_blkid == DMU_SPILL_BLKID) {
2526 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2527 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2528 db->db_blkptr == &dn->dn_phys->dn_spill);
2529 }
2530#endif
2531
2532 if (db->db_level == 0) {
2533 mutex_enter(&dn->dn_mtx);
2534 if (db->db_blkid > dn->dn_phys->dn_maxblkid &&
2535 db->db_blkid != DMU_SPILL_BLKID)
2536 dn->dn_phys->dn_maxblkid = db->db_blkid;
2537 mutex_exit(&dn->dn_mtx);
2538
2539 if (dn->dn_type == DMU_OT_DNODE) {
2540 dnode_phys_t *dnp = db->db.db_data;
2541 for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
2542 i--, dnp++) {
2543 if (dnp->dn_type != DMU_OT_NONE)
2544 fill++;
2545 }
2546 } else {
2547 if (BP_IS_HOLE(bp)) {
2548 fill = 0;
2549 } else {
2550 fill = 1;
2551 }
2552 }
2553 } else {
2554 blkptr_t *ibp = db->db.db_data;
2555 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2556 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
2557 if (BP_IS_HOLE(ibp))
2558 continue;
2559 fill += BP_GET_FILL(ibp);
2560 }
2561 }
2562 DB_DNODE_EXIT(db);
2563
2564 if (!BP_IS_EMBEDDED(bp))
2565 bp->blk_fill = fill;
2566
2567 mutex_exit(&db->db_mtx);
2568}
2569
2570/*
2571 * The SPA will call this callback several times for each zio - once
2572 * for every physical child i/o (zio->io_phys_children times). This
2573 * allows the DMU to monitor the progress of each logical i/o. For example,
2574 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z
2575 * block. There may be a long delay before all copies/fragments are completed,
2576 * so this callback allows us to retire dirty space gradually, as the physical
2577 * i/os complete.
2578 */
2579/* ARGSUSED */
2580static void
2581dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg)
2582{
2583 dmu_buf_impl_t *db = arg;
2584 objset_t *os = db->db_objset;
2585 dsl_pool_t *dp = dmu_objset_pool(os);
2586 dbuf_dirty_record_t *dr;
2587 int delta = 0;
2588
2589 dr = db->db_data_pending;
2590 ASSERT3U(dr->dr_txg, ==, zio->io_txg);
2591
2592 /*
2593 * The callback will be called io_phys_children times. Retire one
2594 * portion of our dirty space each time we are called. Any rounding
2595 * error will be cleaned up by dsl_pool_sync()'s call to
2596 * dsl_pool_undirty_space().
2597 */
2598 delta = dr->dr_accounted / zio->io_phys_children;
2599 dsl_pool_undirty_space(dp, delta, zio->io_txg);
2600}
2601
2602/* ARGSUSED */
2603static void
2604dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
2605{
2606 dmu_buf_impl_t *db = vdb;
2607 blkptr_t *bp_orig = &zio->io_bp_orig;
2608 blkptr_t *bp = db->db_blkptr;
2609 objset_t *os = db->db_objset;
2610 dmu_tx_t *tx = os->os_synctx;
2611 dbuf_dirty_record_t **drp, *dr;
2612
2613 ASSERT0(zio->io_error);
2614 ASSERT(db->db_blkptr == bp);
2615
2616 /*
2617 * For nopwrites and rewrites we ensure that the bp matches our
2618 * original and bypass all the accounting.
2619 */
2620 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) {
2621 ASSERT(BP_EQUAL(bp, bp_orig));
2622 } else {
2623 dsl_dataset_t *ds = os->os_dsl_dataset;
2624 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
2625 dsl_dataset_block_born(ds, bp, tx);
2626 }
2627
2628 mutex_enter(&db->db_mtx);
2629
2630 DBUF_VERIFY(db);
2631
2632 drp = &db->db_last_dirty;
2633 while ((dr = *drp) != db->db_data_pending)
2634 drp = &dr->dr_next;
2635 ASSERT(!list_link_active(&dr->dr_dirty_node));
2636 ASSERT(dr->dr_dbuf == db);
2637 ASSERT(dr->dr_next == NULL);
2638 *drp = dr->dr_next;
2639
2640#ifdef ZFS_DEBUG
2641 if (db->db_blkid == DMU_SPILL_BLKID) {
2642 dnode_t *dn;
2643
2644 DB_DNODE_ENTER(db);
2645 dn = DB_DNODE(db);
2646 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2647 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2648 db->db_blkptr == &dn->dn_phys->dn_spill);
2649 DB_DNODE_EXIT(db);
2650 }
2651#endif
2652
2653 if (db->db_level == 0) {
2654 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
2655 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
2656 if (db->db_state != DB_NOFILL) {
2657 if (dr->dt.dl.dr_data != db->db_buf)
2658 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
2659 db));
2660 else if (!arc_released(db->db_buf))
2661 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2662 }
2663 } else {
2664 dnode_t *dn;
2665
2666 DB_DNODE_ENTER(db);
2667 dn = DB_DNODE(db);
2668 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2669 ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift);
2670 if (!BP_IS_HOLE(db->db_blkptr)) {
2671 int epbs =
2672 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2673 ASSERT3U(db->db_blkid, <=,
2674 dn->dn_phys->dn_maxblkid >> (db->db_level * epbs));
2675 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
2676 db->db.db_size);
2677 if (!arc_released(db->db_buf))
2678 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2679 }
2680 DB_DNODE_EXIT(db);
2681 mutex_destroy(&dr->dt.di.dr_mtx);
2682 list_destroy(&dr->dt.di.dr_children);
2683 }
2684 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2685
2686 cv_broadcast(&db->db_changed);
2687 ASSERT(db->db_dirtycnt > 0);
2688 db->db_dirtycnt -= 1;
2689 db->db_data_pending = NULL;
2690 dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg);
2691}
2692
2693static void
2694dbuf_write_nofill_ready(zio_t *zio)
2695{
2696 dbuf_write_ready(zio, NULL, zio->io_private);
2697}
2698
2699static void
2700dbuf_write_nofill_done(zio_t *zio)
2701{
2702 dbuf_write_done(zio, NULL, zio->io_private);
2703}
2704
2705static void
2706dbuf_write_override_ready(zio_t *zio)
2707{
2708 dbuf_dirty_record_t *dr = zio->io_private;
2709 dmu_buf_impl_t *db = dr->dr_dbuf;
2710
2711 dbuf_write_ready(zio, NULL, db);
2712}
2713
2714static void
2715dbuf_write_override_done(zio_t *zio)
2716{
2717 dbuf_dirty_record_t *dr = zio->io_private;
2718 dmu_buf_impl_t *db = dr->dr_dbuf;
2719 blkptr_t *obp = &dr->dt.dl.dr_overridden_by;
2720
2721 mutex_enter(&db->db_mtx);
2722 if (!BP_EQUAL(zio->io_bp, obp)) {
2723 if (!BP_IS_HOLE(obp))
2724 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp);
2725 arc_release(dr->dt.dl.dr_data, db);
2726 }
2727 mutex_exit(&db->db_mtx);
2728
2729 dbuf_write_done(zio, NULL, db);
2730}
2731
2732/* Issue I/O to commit a dirty buffer to disk. */
2733static void
2734dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
2735{
2736 dmu_buf_impl_t *db = dr->dr_dbuf;
2737 dnode_t *dn;
2738 objset_t *os;
2739 dmu_buf_impl_t *parent = db->db_parent;
2740 uint64_t txg = tx->tx_txg;
2741 zbookmark_phys_t zb;
2742 zio_prop_t zp;
2743 zio_t *zio;
2744 int wp_flag = 0;
2745
2746 DB_DNODE_ENTER(db);
2747 dn = DB_DNODE(db);
2748 os = dn->dn_objset;
2749
2750 if (db->db_state != DB_NOFILL) {
2751 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) {
2752 /*
2753 * Private object buffers are released here rather
2754 * than in dbuf_dirty() since they are only modified
2755 * in the syncing context and we don't want the
2756 * overhead of making multiple copies of the data.
2757 */
2758 if (BP_IS_HOLE(db->db_blkptr)) {
2759 arc_buf_thaw(data);
2760 } else {
2761 dbuf_release_bp(db);
2762 }
2763 }
2764 }
2765
2766 if (parent != dn->dn_dbuf) {
2767 /* Our parent is an indirect block. */
2768 /* We have a dirty parent that has been scheduled for write. */
2769 ASSERT(parent && parent->db_data_pending);
2770 /* Our parent's buffer is one level closer to the dnode. */
2771 ASSERT(db->db_level == parent->db_level-1);
2772 /*
2773 * We're about to modify our parent's db_data by modifying
2774 * our block pointer, so the parent must be released.
2775 */
2776 ASSERT(arc_released(parent->db_buf));
2777 zio = parent->db_data_pending->dr_zio;
2778 } else {
2779 /* Our parent is the dnode itself. */
2780 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 &&
2781 db->db_blkid != DMU_SPILL_BLKID) ||
2782 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0));
2783 if (db->db_blkid != DMU_SPILL_BLKID)
2784 ASSERT3P(db->db_blkptr, ==,
2785 &dn->dn_phys->dn_blkptr[db->db_blkid]);
2786 zio = dn->dn_zio;
2787 }
2788
2789 ASSERT(db->db_level == 0 || data == db->db_buf);
2790 ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
2791 ASSERT(zio);
2792
2793 SET_BOOKMARK(&zb, os->os_dsl_dataset ?
2794 os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
2795 db->db.db_object, db->db_level, db->db_blkid);
2796
2797 if (db->db_blkid == DMU_SPILL_BLKID)
2798 wp_flag = WP_SPILL;
2799 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0;
2800
2801 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp);
2802 DB_DNODE_EXIT(db);
2803
2804 if (db->db_level == 0 &&
2805 dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
2806 /*
2807 * The BP for this block has been provided by open context
2808 * (by dmu_sync() or dmu_buf_write_embedded()).
2809 */
2810 void *contents = (data != NULL) ? data->b_data : NULL;
2811
2812 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2813 db->db_blkptr, contents, db->db.db_size, &zp,
2814 dbuf_write_override_ready, NULL, dbuf_write_override_done,
2815 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2816 mutex_enter(&db->db_mtx);
2817 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
2818 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by,
2819 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite);
2820 mutex_exit(&db->db_mtx);
2821 } else if (db->db_state == DB_NOFILL) {
2822 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF ||
2823 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY);
2824 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2825 db->db_blkptr, NULL, db->db.db_size, &zp,
2826 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db,
2827 ZIO_PRIORITY_ASYNC_WRITE,
2828 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb);
2829 } else {
2830 ASSERT(arc_released(data));
2831 dr->dr_zio = arc_write(zio, os->os_spa, txg,
2832 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db),
2833 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready,
2834 dbuf_write_physdone, dbuf_write_done, db,
2835 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2836 }
2837}
| 2490 list_remove(list, dr);
2491 if (dr->dr_dbuf->db_level > 0)
2492 dbuf_sync_indirect(dr, tx);
2493 else
2494 dbuf_sync_leaf(dr, tx);
2495 }
2496}
2497
2498/* ARGSUSED */
2499static void
2500dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
2501{
2502 dmu_buf_impl_t *db = vdb;
2503 dnode_t *dn;
2504 blkptr_t *bp = zio->io_bp;
2505 blkptr_t *bp_orig = &zio->io_bp_orig;
2506 spa_t *spa = zio->io_spa;
2507 int64_t delta;
2508 uint64_t fill = 0;
2509 int i;
2510
2511 ASSERT3P(db->db_blkptr, ==, bp);
2512
2513 DB_DNODE_ENTER(db);
2514 dn = DB_DNODE(db);
2515 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig);
2516 dnode_diduse_space(dn, delta - zio->io_prev_space_delta);
2517 zio->io_prev_space_delta = delta;
2518
2519 if (bp->blk_birth != 0) {
2520 ASSERT((db->db_blkid != DMU_SPILL_BLKID &&
2521 BP_GET_TYPE(bp) == dn->dn_type) ||
2522 (db->db_blkid == DMU_SPILL_BLKID &&
2523 BP_GET_TYPE(bp) == dn->dn_bonustype) ||
2524 BP_IS_EMBEDDED(bp));
2525 ASSERT(BP_GET_LEVEL(bp) == db->db_level);
2526 }
2527
2528 mutex_enter(&db->db_mtx);
2529
2530#ifdef ZFS_DEBUG
2531 if (db->db_blkid == DMU_SPILL_BLKID) {
2532 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2533 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2534 db->db_blkptr == &dn->dn_phys->dn_spill);
2535 }
2536#endif
2537
2538 if (db->db_level == 0) {
2539 mutex_enter(&dn->dn_mtx);
2540 if (db->db_blkid > dn->dn_phys->dn_maxblkid &&
2541 db->db_blkid != DMU_SPILL_BLKID)
2542 dn->dn_phys->dn_maxblkid = db->db_blkid;
2543 mutex_exit(&dn->dn_mtx);
2544
2545 if (dn->dn_type == DMU_OT_DNODE) {
2546 dnode_phys_t *dnp = db->db.db_data;
2547 for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
2548 i--, dnp++) {
2549 if (dnp->dn_type != DMU_OT_NONE)
2550 fill++;
2551 }
2552 } else {
2553 if (BP_IS_HOLE(bp)) {
2554 fill = 0;
2555 } else {
2556 fill = 1;
2557 }
2558 }
2559 } else {
2560 blkptr_t *ibp = db->db.db_data;
2561 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2562 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
2563 if (BP_IS_HOLE(ibp))
2564 continue;
2565 fill += BP_GET_FILL(ibp);
2566 }
2567 }
2568 DB_DNODE_EXIT(db);
2569
2570 if (!BP_IS_EMBEDDED(bp))
2571 bp->blk_fill = fill;
2572
2573 mutex_exit(&db->db_mtx);
2574}
2575
2576/*
2577 * The SPA will call this callback several times for each zio - once
2578 * for every physical child i/o (zio->io_phys_children times). This
2579 * allows the DMU to monitor the progress of each logical i/o. For example,
2580 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z
2581 * block. There may be a long delay before all copies/fragments are completed,
2582 * so this callback allows us to retire dirty space gradually, as the physical
2583 * i/os complete.
2584 */
2585/* ARGSUSED */
2586static void
2587dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg)
2588{
2589 dmu_buf_impl_t *db = arg;
2590 objset_t *os = db->db_objset;
2591 dsl_pool_t *dp = dmu_objset_pool(os);
2592 dbuf_dirty_record_t *dr;
2593 int delta = 0;
2594
2595 dr = db->db_data_pending;
2596 ASSERT3U(dr->dr_txg, ==, zio->io_txg);
2597
2598 /*
2599 * The callback will be called io_phys_children times. Retire one
2600 * portion of our dirty space each time we are called. Any rounding
2601 * error will be cleaned up by dsl_pool_sync()'s call to
2602 * dsl_pool_undirty_space().
2603 */
2604 delta = dr->dr_accounted / zio->io_phys_children;
2605 dsl_pool_undirty_space(dp, delta, zio->io_txg);
2606}
2607
2608/* ARGSUSED */
2609static void
2610dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
2611{
2612 dmu_buf_impl_t *db = vdb;
2613 blkptr_t *bp_orig = &zio->io_bp_orig;
2614 blkptr_t *bp = db->db_blkptr;
2615 objset_t *os = db->db_objset;
2616 dmu_tx_t *tx = os->os_synctx;
2617 dbuf_dirty_record_t **drp, *dr;
2618
2619 ASSERT0(zio->io_error);
2620 ASSERT(db->db_blkptr == bp);
2621
2622 /*
2623 * For nopwrites and rewrites we ensure that the bp matches our
2624 * original and bypass all the accounting.
2625 */
2626 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) {
2627 ASSERT(BP_EQUAL(bp, bp_orig));
2628 } else {
2629 dsl_dataset_t *ds = os->os_dsl_dataset;
2630 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
2631 dsl_dataset_block_born(ds, bp, tx);
2632 }
2633
2634 mutex_enter(&db->db_mtx);
2635
2636 DBUF_VERIFY(db);
2637
2638 drp = &db->db_last_dirty;
2639 while ((dr = *drp) != db->db_data_pending)
2640 drp = &dr->dr_next;
2641 ASSERT(!list_link_active(&dr->dr_dirty_node));
2642 ASSERT(dr->dr_dbuf == db);
2643 ASSERT(dr->dr_next == NULL);
2644 *drp = dr->dr_next;
2645
2646#ifdef ZFS_DEBUG
2647 if (db->db_blkid == DMU_SPILL_BLKID) {
2648 dnode_t *dn;
2649
2650 DB_DNODE_ENTER(db);
2651 dn = DB_DNODE(db);
2652 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2653 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2654 db->db_blkptr == &dn->dn_phys->dn_spill);
2655 DB_DNODE_EXIT(db);
2656 }
2657#endif
2658
2659 if (db->db_level == 0) {
2660 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
2661 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
2662 if (db->db_state != DB_NOFILL) {
2663 if (dr->dt.dl.dr_data != db->db_buf)
2664 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
2665 db));
2666 else if (!arc_released(db->db_buf))
2667 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2668 }
2669 } else {
2670 dnode_t *dn;
2671
2672 DB_DNODE_ENTER(db);
2673 dn = DB_DNODE(db);
2674 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2675 ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift);
2676 if (!BP_IS_HOLE(db->db_blkptr)) {
2677 int epbs =
2678 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2679 ASSERT3U(db->db_blkid, <=,
2680 dn->dn_phys->dn_maxblkid >> (db->db_level * epbs));
2681 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
2682 db->db.db_size);
2683 if (!arc_released(db->db_buf))
2684 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2685 }
2686 DB_DNODE_EXIT(db);
2687 mutex_destroy(&dr->dt.di.dr_mtx);
2688 list_destroy(&dr->dt.di.dr_children);
2689 }
2690 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2691
2692 cv_broadcast(&db->db_changed);
2693 ASSERT(db->db_dirtycnt > 0);
2694 db->db_dirtycnt -= 1;
2695 db->db_data_pending = NULL;
2696 dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg);
2697}
2698
2699static void
2700dbuf_write_nofill_ready(zio_t *zio)
2701{
2702 dbuf_write_ready(zio, NULL, zio->io_private);
2703}
2704
2705static void
2706dbuf_write_nofill_done(zio_t *zio)
2707{
2708 dbuf_write_done(zio, NULL, zio->io_private);
2709}
2710
2711static void
2712dbuf_write_override_ready(zio_t *zio)
2713{
2714 dbuf_dirty_record_t *dr = zio->io_private;
2715 dmu_buf_impl_t *db = dr->dr_dbuf;
2716
2717 dbuf_write_ready(zio, NULL, db);
2718}
2719
2720static void
2721dbuf_write_override_done(zio_t *zio)
2722{
2723 dbuf_dirty_record_t *dr = zio->io_private;
2724 dmu_buf_impl_t *db = dr->dr_dbuf;
2725 blkptr_t *obp = &dr->dt.dl.dr_overridden_by;
2726
2727 mutex_enter(&db->db_mtx);
2728 if (!BP_EQUAL(zio->io_bp, obp)) {
2729 if (!BP_IS_HOLE(obp))
2730 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp);
2731 arc_release(dr->dt.dl.dr_data, db);
2732 }
2733 mutex_exit(&db->db_mtx);
2734
2735 dbuf_write_done(zio, NULL, db);
2736}
2737
2738/* Issue I/O to commit a dirty buffer to disk. */
2739static void
2740dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
2741{
2742 dmu_buf_impl_t *db = dr->dr_dbuf;
2743 dnode_t *dn;
2744 objset_t *os;
2745 dmu_buf_impl_t *parent = db->db_parent;
2746 uint64_t txg = tx->tx_txg;
2747 zbookmark_phys_t zb;
2748 zio_prop_t zp;
2749 zio_t *zio;
2750 int wp_flag = 0;
2751
2752 DB_DNODE_ENTER(db);
2753 dn = DB_DNODE(db);
2754 os = dn->dn_objset;
2755
2756 if (db->db_state != DB_NOFILL) {
2757 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) {
2758 /*
2759 * Private object buffers are released here rather
2760 * than in dbuf_dirty() since they are only modified
2761 * in the syncing context and we don't want the
2762 * overhead of making multiple copies of the data.
2763 */
2764 if (BP_IS_HOLE(db->db_blkptr)) {
2765 arc_buf_thaw(data);
2766 } else {
2767 dbuf_release_bp(db);
2768 }
2769 }
2770 }
2771
2772 if (parent != dn->dn_dbuf) {
2773 /* Our parent is an indirect block. */
2774 /* We have a dirty parent that has been scheduled for write. */
2775 ASSERT(parent && parent->db_data_pending);
2776 /* Our parent's buffer is one level closer to the dnode. */
2777 ASSERT(db->db_level == parent->db_level-1);
2778 /*
2779 * We're about to modify our parent's db_data by modifying
2780 * our block pointer, so the parent must be released.
2781 */
2782 ASSERT(arc_released(parent->db_buf));
2783 zio = parent->db_data_pending->dr_zio;
2784 } else {
2785 /* Our parent is the dnode itself. */
2786 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 &&
2787 db->db_blkid != DMU_SPILL_BLKID) ||
2788 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0));
2789 if (db->db_blkid != DMU_SPILL_BLKID)
2790 ASSERT3P(db->db_blkptr, ==,
2791 &dn->dn_phys->dn_blkptr[db->db_blkid]);
2792 zio = dn->dn_zio;
2793 }
2794
2795 ASSERT(db->db_level == 0 || data == db->db_buf);
2796 ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
2797 ASSERT(zio);
2798
2799 SET_BOOKMARK(&zb, os->os_dsl_dataset ?
2800 os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
2801 db->db.db_object, db->db_level, db->db_blkid);
2802
2803 if (db->db_blkid == DMU_SPILL_BLKID)
2804 wp_flag = WP_SPILL;
2805 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0;
2806
2807 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp);
2808 DB_DNODE_EXIT(db);
2809
2810 if (db->db_level == 0 &&
2811 dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
2812 /*
2813 * The BP for this block has been provided by open context
2814 * (by dmu_sync() or dmu_buf_write_embedded()).
2815 */
2816 void *contents = (data != NULL) ? data->b_data : NULL;
2817
2818 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2819 db->db_blkptr, contents, db->db.db_size, &zp,
2820 dbuf_write_override_ready, NULL, dbuf_write_override_done,
2821 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2822 mutex_enter(&db->db_mtx);
2823 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
2824 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by,
2825 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite);
2826 mutex_exit(&db->db_mtx);
2827 } else if (db->db_state == DB_NOFILL) {
2828 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF ||
2829 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY);
2830 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2831 db->db_blkptr, NULL, db->db.db_size, &zp,
2832 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db,
2833 ZIO_PRIORITY_ASYNC_WRITE,
2834 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb);
2835 } else {
2836 ASSERT(arc_released(data));
2837 dr->dr_zio = arc_write(zio, os->os_spa, txg,
2838 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db),
2839 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready,
2840 dbuf_write_physdone, dbuf_write_done, db,
2841 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2842 }
2843}
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