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.
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.
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]
22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
26 #include <sys/zfs_context.h>
28 #include <sys/dmu_impl.h>
30 #include <sys/dmu_objset.h>
31 #include <sys/dsl_dataset.h>
32 #include <sys/dsl_dir.h>
33 #include <sys/dmu_tx.h>
36 #include <sys/dmu_zfetch.h>
38 static void dbuf_destroy(dmu_buf_impl_t *db);
39 static int dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
40 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
41 static arc_done_func_t dbuf_write_ready;
42 static arc_done_func_t dbuf_write_done;
43 static zio_done_func_t dbuf_skip_write_ready;
44 static zio_done_func_t dbuf_skip_write_done;
47 * Global data structures and functions for the dbuf cache.
49 static kmem_cache_t *dbuf_cache;
53 dbuf_cons(void *vdb, void *unused, int kmflag)
55 dmu_buf_impl_t *db = vdb;
56 bzero(db, sizeof (dmu_buf_impl_t));
58 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
59 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
60 refcount_create(&db->db_holds);
66 dbuf_dest(void *vdb, void *unused)
68 dmu_buf_impl_t *db = vdb;
69 mutex_destroy(&db->db_mtx);
70 cv_destroy(&db->db_changed);
71 refcount_destroy(&db->db_holds);
75 * dbuf hash table routines
77 static dbuf_hash_table_t dbuf_hash_table;
79 static uint64_t dbuf_hash_count;
82 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
84 uintptr_t osv = (uintptr_t)os;
87 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
88 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
89 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
90 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
91 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
92 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
93 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
95 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
100 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
102 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
103 ((dbuf)->db.db_object == (obj) && \
104 (dbuf)->db_objset == (os) && \
105 (dbuf)->db_level == (level) && \
106 (dbuf)->db_blkid == (blkid))
109 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
111 dbuf_hash_table_t *h = &dbuf_hash_table;
112 objset_impl_t *os = dn->dn_objset;
113 uint64_t obj = dn->dn_object;
114 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
115 uint64_t idx = hv & h->hash_table_mask;
118 mutex_enter(DBUF_HASH_MUTEX(h, idx));
119 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
120 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
121 mutex_enter(&db->db_mtx);
122 if (db->db_state != DB_EVICTING) {
123 mutex_exit(DBUF_HASH_MUTEX(h, idx));
126 mutex_exit(&db->db_mtx);
129 mutex_exit(DBUF_HASH_MUTEX(h, idx));
134 * Insert an entry into the hash table. If there is already an element
135 * equal to elem in the hash table, then the already existing element
136 * will be returned and the new element will not be inserted.
137 * Otherwise returns NULL.
139 static dmu_buf_impl_t *
140 dbuf_hash_insert(dmu_buf_impl_t *db)
142 dbuf_hash_table_t *h = &dbuf_hash_table;
143 objset_impl_t *os = db->db_objset;
144 uint64_t obj = db->db.db_object;
145 int level = db->db_level;
146 uint64_t blkid = db->db_blkid;
147 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
148 uint64_t idx = hv & h->hash_table_mask;
151 mutex_enter(DBUF_HASH_MUTEX(h, idx));
152 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
153 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
154 mutex_enter(&dbf->db_mtx);
155 if (dbf->db_state != DB_EVICTING) {
156 mutex_exit(DBUF_HASH_MUTEX(h, idx));
159 mutex_exit(&dbf->db_mtx);
163 mutex_enter(&db->db_mtx);
164 db->db_hash_next = h->hash_table[idx];
165 h->hash_table[idx] = db;
166 mutex_exit(DBUF_HASH_MUTEX(h, idx));
167 atomic_add_64(&dbuf_hash_count, 1);
173 * Remove an entry from the hash table. This operation will
174 * fail if there are any existing holds on the db.
177 dbuf_hash_remove(dmu_buf_impl_t *db)
179 dbuf_hash_table_t *h = &dbuf_hash_table;
180 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object,
181 db->db_level, db->db_blkid);
182 uint64_t idx = hv & h->hash_table_mask;
183 dmu_buf_impl_t *dbf, **dbp;
186 * We musn't hold db_mtx to maintin lock ordering:
187 * DBUF_HASH_MUTEX > db_mtx.
189 ASSERT(refcount_is_zero(&db->db_holds));
190 ASSERT(db->db_state == DB_EVICTING);
191 ASSERT(!MUTEX_HELD(&db->db_mtx));
193 mutex_enter(DBUF_HASH_MUTEX(h, idx));
194 dbp = &h->hash_table[idx];
195 while ((dbf = *dbp) != db) {
196 dbp = &dbf->db_hash_next;
199 *dbp = db->db_hash_next;
200 db->db_hash_next = NULL;
201 mutex_exit(DBUF_HASH_MUTEX(h, idx));
202 atomic_add_64(&dbuf_hash_count, -1);
205 static arc_evict_func_t dbuf_do_evict;
208 dbuf_evict_user(dmu_buf_impl_t *db)
210 ASSERT(MUTEX_HELD(&db->db_mtx));
212 if (db->db_level != 0 || db->db_evict_func == NULL)
215 if (db->db_user_data_ptr_ptr)
216 *db->db_user_data_ptr_ptr = db->db.db_data;
217 db->db_evict_func(&db->db, db->db_user_ptr);
218 db->db_user_ptr = NULL;
219 db->db_user_data_ptr_ptr = NULL;
220 db->db_evict_func = NULL;
224 dbuf_evict(dmu_buf_impl_t *db)
226 ASSERT(MUTEX_HELD(&db->db_mtx));
227 ASSERT(db->db_buf == NULL);
228 ASSERT(db->db_data_pending == NULL);
237 uint64_t hsize = 1ULL << 16;
238 dbuf_hash_table_t *h = &dbuf_hash_table;
242 * The hash table is big enough to fill all of physical memory
243 * with an average 4K block size. The table will take up
244 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
246 while (hsize * 4096 < physmem * PAGESIZE)
250 h->hash_table_mask = hsize - 1;
251 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
252 if (h->hash_table == NULL) {
253 /* XXX - we should really return an error instead of assert */
254 ASSERT(hsize > (1ULL << 10));
259 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
260 sizeof (dmu_buf_impl_t),
261 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
263 for (i = 0; i < DBUF_MUTEXES; i++)
264 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
270 dbuf_hash_table_t *h = &dbuf_hash_table;
273 for (i = 0; i < DBUF_MUTEXES; i++)
274 mutex_destroy(&h->hash_mutexes[i]);
275 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
276 kmem_cache_destroy(dbuf_cache);
285 dbuf_verify(dmu_buf_impl_t *db)
287 dnode_t *dn = db->db_dnode;
289 ASSERT(MUTEX_HELD(&db->db_mtx));
291 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
294 ASSERT(db->db_objset != NULL);
296 ASSERT(db->db_parent == NULL);
297 ASSERT(db->db_blkptr == NULL);
299 ASSERT3U(db->db.db_object, ==, dn->dn_object);
300 ASSERT3P(db->db_objset, ==, dn->dn_objset);
301 ASSERT3U(db->db_level, <, dn->dn_nlevels);
302 ASSERT(db->db_blkid == DB_BONUS_BLKID ||
303 list_head(&dn->dn_dbufs));
305 if (db->db_blkid == DB_BONUS_BLKID) {
307 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
308 ASSERT3U(db->db.db_offset, ==, DB_BONUS_BLKID);
310 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
314 * We can't assert that db_size matches dn_datablksz because it
315 * can be momentarily different when another thread is doing
318 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
319 dbuf_dirty_record_t *dr = db->db_data_pending;
321 * It should only be modified in syncing context, so
322 * make sure we only have one copy of the data.
324 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
327 /* verify db->db_blkptr */
329 if (db->db_parent == dn->dn_dbuf) {
330 /* db is pointed to by the dnode */
331 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
332 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
333 ASSERT(db->db_parent == NULL);
335 ASSERT(db->db_parent != NULL);
336 ASSERT3P(db->db_blkptr, ==,
337 &dn->dn_phys->dn_blkptr[db->db_blkid]);
339 /* db is pointed to by an indirect block */
340 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT;
341 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
342 ASSERT3U(db->db_parent->db.db_object, ==,
345 * dnode_grow_indblksz() can make this fail if we don't
346 * have the struct_rwlock. XXX indblksz no longer
347 * grows. safe to do this now?
349 if (RW_WRITE_HELD(&db->db_dnode->dn_struct_rwlock)) {
350 ASSERT3P(db->db_blkptr, ==,
351 ((blkptr_t *)db->db_parent->db.db_data +
352 db->db_blkid % epb));
356 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
357 db->db.db_data && db->db_blkid != DB_BONUS_BLKID &&
358 db->db_state != DB_FILL && !dn->dn_free_txg) {
360 * If the blkptr isn't set but they have nonzero data,
361 * it had better be dirty, otherwise we'll lose that
362 * data when we evict this buffer.
364 if (db->db_dirtycnt == 0) {
365 uint64_t *buf = db->db.db_data;
368 for (i = 0; i < db->db.db_size >> 3; i++) {
377 dbuf_update_data(dmu_buf_impl_t *db)
379 ASSERT(MUTEX_HELD(&db->db_mtx));
380 if (db->db_level == 0 && db->db_user_data_ptr_ptr) {
381 ASSERT(!refcount_is_zero(&db->db_holds));
382 *db->db_user_data_ptr_ptr = db->db.db_data;
387 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
389 ASSERT(MUTEX_HELD(&db->db_mtx));
390 ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf));
393 ASSERT(buf->b_data != NULL);
394 db->db.db_data = buf->b_data;
395 if (!arc_released(buf))
396 arc_set_callback(buf, dbuf_do_evict, db);
397 dbuf_update_data(db);
400 db->db.db_data = NULL;
401 if (db->db_state != DB_NOFILL)
402 db->db_state = DB_UNCACHED;
407 dbuf_whichblock(dnode_t *dn, uint64_t offset)
409 if (dn->dn_datablkshift) {
410 return (offset >> dn->dn_datablkshift);
412 ASSERT3U(offset, <, dn->dn_datablksz);
418 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
420 dmu_buf_impl_t *db = vdb;
422 mutex_enter(&db->db_mtx);
423 ASSERT3U(db->db_state, ==, DB_READ);
425 * All reads are synchronous, so we must have a hold on the dbuf
427 ASSERT(refcount_count(&db->db_holds) > 0);
428 ASSERT(db->db_buf == NULL);
429 ASSERT(db->db.db_data == NULL);
430 if (db->db_level == 0 && db->db_freed_in_flight) {
431 /* we were freed in flight; disregard any error */
432 arc_release(buf, db);
433 bzero(buf->b_data, db->db.db_size);
435 db->db_freed_in_flight = FALSE;
436 dbuf_set_data(db, buf);
437 db->db_state = DB_CACHED;
438 } else if (zio == NULL || zio->io_error == 0) {
439 dbuf_set_data(db, buf);
440 db->db_state = DB_CACHED;
442 ASSERT(db->db_blkid != DB_BONUS_BLKID);
443 ASSERT3P(db->db_buf, ==, NULL);
444 VERIFY(arc_buf_remove_ref(buf, db) == 1);
445 db->db_state = DB_UNCACHED;
447 cv_broadcast(&db->db_changed);
448 mutex_exit(&db->db_mtx);
453 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
455 dnode_t *dn = db->db_dnode;
457 uint32_t aflags = ARC_NOWAIT;
460 ASSERT(!refcount_is_zero(&db->db_holds));
461 /* We need the struct_rwlock to prevent db_blkptr from changing. */
462 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
463 ASSERT(MUTEX_HELD(&db->db_mtx));
464 ASSERT(db->db_state == DB_UNCACHED);
465 ASSERT(db->db_buf == NULL);
467 if (db->db_blkid == DB_BONUS_BLKID) {
468 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
470 ASSERT3U(bonuslen, <=, db->db.db_size);
471 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
472 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
473 if (bonuslen < DN_MAX_BONUSLEN)
474 bzero(db->db.db_data, DN_MAX_BONUSLEN);
476 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
477 dbuf_update_data(db);
478 db->db_state = DB_CACHED;
479 mutex_exit(&db->db_mtx);
484 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
485 * processes the delete record and clears the bp while we are waiting
486 * for the dn_mtx (resulting in a "no" from block_freed).
488 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
489 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
490 BP_IS_HOLE(db->db_blkptr)))) {
491 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
493 dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa,
494 db->db.db_size, db, type));
495 bzero(db->db.db_data, db->db.db_size);
496 db->db_state = DB_CACHED;
497 *flags |= DB_RF_CACHED;
498 mutex_exit(&db->db_mtx);
502 db->db_state = DB_READ;
503 mutex_exit(&db->db_mtx);
505 if (DBUF_IS_L2CACHEABLE(db))
506 aflags |= ARC_L2CACHE;
508 zb.zb_objset = db->db_objset->os_dsl_dataset ?
509 db->db_objset->os_dsl_dataset->ds_object : 0;
510 zb.zb_object = db->db.db_object;
511 zb.zb_level = db->db_level;
512 zb.zb_blkid = db->db_blkid;
514 dbuf_add_ref(db, NULL);
515 /* ZIO_FLAG_CANFAIL callers have to check the parent zio's error */
518 pbuf = db->db_parent->db_buf;
520 pbuf = db->db_objset->os_phys_buf;
522 (void) arc_read(zio, dn->dn_objset->os_spa, db->db_blkptr, pbuf,
523 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
524 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
526 if (aflags & ARC_CACHED)
527 *flags |= DB_RF_CACHED;
531 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
534 int havepzio = (zio != NULL);
538 * We don't have to hold the mutex to check db_state because it
539 * can't be freed while we have a hold on the buffer.
541 ASSERT(!refcount_is_zero(&db->db_holds));
543 if (db->db_state == DB_NOFILL)
546 if ((flags & DB_RF_HAVESTRUCT) == 0)
547 rw_enter(&db->db_dnode->dn_struct_rwlock, RW_READER);
549 prefetch = db->db_level == 0 && db->db_blkid != DB_BONUS_BLKID &&
550 (flags & DB_RF_NOPREFETCH) == 0 && db->db_dnode != NULL &&
551 DBUF_IS_CACHEABLE(db);
553 mutex_enter(&db->db_mtx);
554 if (db->db_state == DB_CACHED) {
555 mutex_exit(&db->db_mtx);
557 dmu_zfetch(&db->db_dnode->dn_zfetch, db->db.db_offset,
558 db->db.db_size, TRUE);
559 if ((flags & DB_RF_HAVESTRUCT) == 0)
560 rw_exit(&db->db_dnode->dn_struct_rwlock);
561 } else if (db->db_state == DB_UNCACHED) {
563 zio = zio_root(db->db_dnode->dn_objset->os_spa,
564 NULL, NULL, ZIO_FLAG_CANFAIL);
566 dbuf_read_impl(db, zio, &flags);
568 /* dbuf_read_impl has dropped db_mtx for us */
571 dmu_zfetch(&db->db_dnode->dn_zfetch, db->db.db_offset,
572 db->db.db_size, flags & DB_RF_CACHED);
574 if ((flags & DB_RF_HAVESTRUCT) == 0)
575 rw_exit(&db->db_dnode->dn_struct_rwlock);
580 mutex_exit(&db->db_mtx);
582 dmu_zfetch(&db->db_dnode->dn_zfetch, db->db.db_offset,
583 db->db.db_size, TRUE);
584 if ((flags & DB_RF_HAVESTRUCT) == 0)
585 rw_exit(&db->db_dnode->dn_struct_rwlock);
587 mutex_enter(&db->db_mtx);
588 if ((flags & DB_RF_NEVERWAIT) == 0) {
589 while (db->db_state == DB_READ ||
590 db->db_state == DB_FILL) {
591 ASSERT(db->db_state == DB_READ ||
592 (flags & DB_RF_HAVESTRUCT) == 0);
593 cv_wait(&db->db_changed, &db->db_mtx);
595 if (db->db_state == DB_UNCACHED)
598 mutex_exit(&db->db_mtx);
601 ASSERT(err || havepzio || db->db_state == DB_CACHED);
606 dbuf_noread(dmu_buf_impl_t *db)
608 ASSERT(!refcount_is_zero(&db->db_holds));
609 ASSERT(db->db_blkid != DB_BONUS_BLKID);
610 mutex_enter(&db->db_mtx);
611 while (db->db_state == DB_READ || db->db_state == DB_FILL)
612 cv_wait(&db->db_changed, &db->db_mtx);
613 if (db->db_state == DB_UNCACHED) {
614 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
616 ASSERT(db->db_buf == NULL);
617 ASSERT(db->db.db_data == NULL);
618 dbuf_set_data(db, arc_buf_alloc(db->db_dnode->dn_objset->os_spa,
619 db->db.db_size, db, type));
620 db->db_state = DB_FILL;
621 } else if (db->db_state == DB_NOFILL) {
622 dbuf_set_data(db, NULL);
624 ASSERT3U(db->db_state, ==, DB_CACHED);
626 mutex_exit(&db->db_mtx);
630 * This is our just-in-time copy function. It makes a copy of
631 * buffers, that have been modified in a previous transaction
632 * group, before we modify them in the current active group.
634 * This function is used in two places: when we are dirtying a
635 * buffer for the first time in a txg, and when we are freeing
636 * a range in a dnode that includes this buffer.
638 * Note that when we are called from dbuf_free_range() we do
639 * not put a hold on the buffer, we just traverse the active
640 * dbuf list for the dnode.
643 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
645 dbuf_dirty_record_t *dr = db->db_last_dirty;
647 ASSERT(MUTEX_HELD(&db->db_mtx));
648 ASSERT(db->db.db_data != NULL);
649 ASSERT(db->db_level == 0);
650 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT);
653 (dr->dt.dl.dr_data !=
654 ((db->db_blkid == DB_BONUS_BLKID) ? db->db.db_data : db->db_buf)))
658 * If the last dirty record for this dbuf has not yet synced
659 * and its referencing the dbuf data, either:
660 * reset the reference to point to a new copy,
661 * or (if there a no active holders)
662 * just null out the current db_data pointer.
664 ASSERT(dr->dr_txg >= txg - 2);
665 if (db->db_blkid == DB_BONUS_BLKID) {
666 /* Note that the data bufs here are zio_bufs */
667 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
668 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
669 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
670 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
671 int size = db->db.db_size;
672 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
673 dr->dt.dl.dr_data = arc_buf_alloc(
674 db->db_dnode->dn_objset->os_spa, size, db, type);
675 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
677 dbuf_set_data(db, NULL);
682 dbuf_unoverride(dbuf_dirty_record_t *dr)
684 dmu_buf_impl_t *db = dr->dr_dbuf;
685 uint64_t txg = dr->dr_txg;
687 ASSERT(MUTEX_HELD(&db->db_mtx));
688 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
689 ASSERT(db->db_level == 0);
691 if (db->db_blkid == DB_BONUS_BLKID ||
692 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
695 /* free this block */
696 if (!BP_IS_HOLE(&dr->dt.dl.dr_overridden_by)) {
697 /* XXX can get silent EIO here */
698 (void) dsl_free(NULL,
699 spa_get_dsl(db->db_dnode->dn_objset->os_spa),
700 txg, &dr->dt.dl.dr_overridden_by, NULL, NULL, ARC_WAIT);
702 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
704 * Release the already-written buffer, so we leave it in
705 * a consistent dirty state. Note that all callers are
706 * modifying the buffer, so they will immediately do
707 * another (redundant) arc_release(). Therefore, leave
708 * the buf thawed to save the effort of freezing &
709 * immediately re-thawing it.
711 arc_release(dr->dt.dl.dr_data, db);
715 * Evict (if its unreferenced) or clear (if its referenced) any level-0
716 * data blocks in the free range, so that any future readers will find
717 * empty blocks. Also, if we happen accross any level-1 dbufs in the
718 * range that have not already been marked dirty, mark them dirty so
719 * they stay in memory.
722 dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
724 dmu_buf_impl_t *db, *db_next;
725 uint64_t txg = tx->tx_txg;
726 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
727 uint64_t first_l1 = start >> epbs;
728 uint64_t last_l1 = end >> epbs;
730 if (end > dn->dn_maxblkid) {
731 end = dn->dn_maxblkid;
732 last_l1 = end >> epbs;
734 dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
735 mutex_enter(&dn->dn_dbufs_mtx);
736 for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
737 db_next = list_next(&dn->dn_dbufs, db);
738 ASSERT(db->db_blkid != DB_BONUS_BLKID);
740 if (db->db_level == 1 &&
741 db->db_blkid >= first_l1 && db->db_blkid <= last_l1) {
742 mutex_enter(&db->db_mtx);
743 if (db->db_last_dirty &&
744 db->db_last_dirty->dr_txg < txg) {
745 dbuf_add_ref(db, FTAG);
746 mutex_exit(&db->db_mtx);
747 dbuf_will_dirty(db, tx);
750 mutex_exit(&db->db_mtx);
754 if (db->db_level != 0)
756 dprintf_dbuf(db, "found buf %s\n", "");
757 if (db->db_blkid < start || db->db_blkid > end)
760 /* found a level 0 buffer in the range */
761 if (dbuf_undirty(db, tx))
764 mutex_enter(&db->db_mtx);
765 if (db->db_state == DB_UNCACHED ||
766 db->db_state == DB_NOFILL ||
767 db->db_state == DB_EVICTING) {
768 ASSERT(db->db.db_data == NULL);
769 mutex_exit(&db->db_mtx);
772 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
773 /* will be handled in dbuf_read_done or dbuf_rele */
774 db->db_freed_in_flight = TRUE;
775 mutex_exit(&db->db_mtx);
778 if (refcount_count(&db->db_holds) == 0) {
783 /* The dbuf is referenced */
785 if (db->db_last_dirty != NULL) {
786 dbuf_dirty_record_t *dr = db->db_last_dirty;
788 if (dr->dr_txg == txg) {
790 * This buffer is "in-use", re-adjust the file
791 * size to reflect that this buffer may
792 * contain new data when we sync.
794 if (db->db_blkid > dn->dn_maxblkid)
795 dn->dn_maxblkid = db->db_blkid;
799 * This dbuf is not dirty in the open context.
800 * Either uncache it (if its not referenced in
801 * the open context) or reset its contents to
804 dbuf_fix_old_data(db, txg);
807 /* clear the contents if its cached */
808 if (db->db_state == DB_CACHED) {
809 ASSERT(db->db.db_data != NULL);
810 arc_release(db->db_buf, db);
811 bzero(db->db.db_data, db->db.db_size);
812 arc_buf_freeze(db->db_buf);
815 mutex_exit(&db->db_mtx);
817 mutex_exit(&dn->dn_dbufs_mtx);
821 dbuf_block_freeable(dmu_buf_impl_t *db)
823 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
824 uint64_t birth_txg = 0;
827 * We don't need any locking to protect db_blkptr:
828 * If it's syncing, then db_last_dirty will be set
829 * so we'll ignore db_blkptr.
831 ASSERT(MUTEX_HELD(&db->db_mtx));
832 if (db->db_last_dirty)
833 birth_txg = db->db_last_dirty->dr_txg;
834 else if (db->db_blkptr)
835 birth_txg = db->db_blkptr->blk_birth;
837 /* If we don't exist or are in a snapshot, we can't be freed */
839 return (ds == NULL ||
840 dsl_dataset_block_freeable(ds, birth_txg));
846 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
848 arc_buf_t *buf, *obuf;
849 int osize = db->db.db_size;
850 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
852 ASSERT(db->db_blkid != DB_BONUS_BLKID);
854 /* XXX does *this* func really need the lock? */
855 ASSERT(RW_WRITE_HELD(&db->db_dnode->dn_struct_rwlock));
858 * This call to dbuf_will_dirty() with the dn_struct_rwlock held
859 * is OK, because there can be no other references to the db
860 * when we are changing its size, so no concurrent DB_FILL can
864 * XXX we should be doing a dbuf_read, checking the return
865 * value and returning that up to our callers
867 dbuf_will_dirty(db, tx);
869 /* create the data buffer for the new block */
870 buf = arc_buf_alloc(db->db_dnode->dn_objset->os_spa, size, db, type);
872 /* copy old block data to the new block */
874 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
875 /* zero the remainder */
877 bzero((uint8_t *)buf->b_data + osize, size - osize);
879 mutex_enter(&db->db_mtx);
880 dbuf_set_data(db, buf);
881 VERIFY(arc_buf_remove_ref(obuf, db) == 1);
882 db->db.db_size = size;
884 if (db->db_level == 0) {
885 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
886 db->db_last_dirty->dt.dl.dr_data = buf;
888 mutex_exit(&db->db_mtx);
890 dnode_willuse_space(db->db_dnode, size-osize, tx);
893 dbuf_dirty_record_t *
894 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
896 dnode_t *dn = db->db_dnode;
897 objset_impl_t *os = dn->dn_objset;
898 dbuf_dirty_record_t **drp, *dr;
899 int drop_struct_lock = FALSE;
900 boolean_t do_free_accounting = B_FALSE;
901 int txgoff = tx->tx_txg & TXG_MASK;
903 ASSERT(tx->tx_txg != 0);
904 ASSERT(!refcount_is_zero(&db->db_holds));
905 DMU_TX_DIRTY_BUF(tx, db);
908 * Shouldn't dirty a regular buffer in syncing context. Private
909 * objects may be dirtied in syncing context, but only if they
910 * were already pre-dirtied in open context.
912 ASSERT(!dmu_tx_is_syncing(tx) ||
913 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
914 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
915 dn->dn_objset->os_dsl_dataset == NULL);
917 * We make this assert for private objects as well, but after we
918 * check if we're already dirty. They are allowed to re-dirty
919 * in syncing context.
921 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
922 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
923 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
925 mutex_enter(&db->db_mtx);
927 * XXX make this true for indirects too? The problem is that
928 * transactions created with dmu_tx_create_assigned() from
929 * syncing context don't bother holding ahead.
931 ASSERT(db->db_level != 0 ||
932 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
933 db->db_state == DB_NOFILL);
935 mutex_enter(&dn->dn_mtx);
937 * Don't set dirtyctx to SYNC if we're just modifying this as we
938 * initialize the objset.
940 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
941 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
943 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
944 ASSERT(dn->dn_dirtyctx_firstset == NULL);
945 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
947 mutex_exit(&dn->dn_mtx);
950 * If this buffer is already dirty, we're done.
952 drp = &db->db_last_dirty;
953 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
954 db->db.db_object == DMU_META_DNODE_OBJECT);
955 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
957 if (dr && dr->dr_txg == tx->tx_txg) {
958 if (db->db_level == 0 && db->db_blkid != DB_BONUS_BLKID) {
960 * If this buffer has already been written out,
961 * we now need to reset its state.
964 if (db->db.db_object != DMU_META_DNODE_OBJECT)
965 arc_buf_thaw(db->db_buf);
967 mutex_exit(&db->db_mtx);
972 * Only valid if not already dirty.
974 ASSERT(dn->dn_object == 0 ||
975 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
976 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
978 ASSERT3U(dn->dn_nlevels, >, db->db_level);
979 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
980 dn->dn_phys->dn_nlevels > db->db_level ||
981 dn->dn_next_nlevels[txgoff] > db->db_level ||
982 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
983 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
986 * We should only be dirtying in syncing context if it's the
987 * mos or we're initializing the os or it's a special object.
988 * However, we are allowed to dirty in syncing context provided
989 * we already dirtied it in open context. Hence we must make
990 * this assertion only if we're not already dirty.
992 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
993 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
994 ASSERT(db->db.db_size != 0);
996 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
998 if (db->db_blkid != DB_BONUS_BLKID) {
1000 * Update the accounting.
1001 * Note: we delay "free accounting" until after we drop
1002 * the db_mtx. This keeps us from grabbing other locks
1003 * (and possibly deadlocking) in bp_get_dasize() while
1004 * also holding the db_mtx.
1006 dnode_willuse_space(dn, db->db.db_size, tx);
1007 do_free_accounting = dbuf_block_freeable(db);
1011 * If this buffer is dirty in an old transaction group we need
1012 * to make a copy of it so that the changes we make in this
1013 * transaction group won't leak out when we sync the older txg.
1015 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP);
1016 if (db->db_level == 0) {
1017 void *data_old = db->db_buf;
1019 if (db->db_state != DB_NOFILL) {
1020 if (db->db_blkid == DB_BONUS_BLKID) {
1021 dbuf_fix_old_data(db, tx->tx_txg);
1022 data_old = db->db.db_data;
1023 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1025 * Release the data buffer from the cache so
1026 * that we can modify it without impacting
1027 * possible other users of this cached data
1028 * block. Note that indirect blocks and
1029 * private objects are not released until the
1030 * syncing state (since they are only modified
1033 arc_release(db->db_buf, db);
1034 dbuf_fix_old_data(db, tx->tx_txg);
1035 data_old = db->db_buf;
1037 ASSERT(data_old != NULL);
1039 dr->dt.dl.dr_data = data_old;
1041 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1042 list_create(&dr->dt.di.dr_children,
1043 sizeof (dbuf_dirty_record_t),
1044 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1047 dr->dr_txg = tx->tx_txg;
1052 * We could have been freed_in_flight between the dbuf_noread
1053 * and dbuf_dirty. We win, as though the dbuf_noread() had
1054 * happened after the free.
1056 if (db->db_level == 0 && db->db_blkid != DB_BONUS_BLKID) {
1057 mutex_enter(&dn->dn_mtx);
1058 dnode_clear_range(dn, db->db_blkid, 1, tx);
1059 mutex_exit(&dn->dn_mtx);
1060 db->db_freed_in_flight = FALSE;
1064 * This buffer is now part of this txg
1066 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1067 db->db_dirtycnt += 1;
1068 ASSERT3U(db->db_dirtycnt, <=, 3);
1070 mutex_exit(&db->db_mtx);
1072 if (db->db_blkid == DB_BONUS_BLKID) {
1073 mutex_enter(&dn->dn_mtx);
1074 ASSERT(!list_link_active(&dr->dr_dirty_node));
1075 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1076 mutex_exit(&dn->dn_mtx);
1077 dnode_setdirty(dn, tx);
1079 } else if (do_free_accounting) {
1080 blkptr_t *bp = db->db_blkptr;
1081 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1082 bp_get_dasize(os->os_spa, bp) : db->db.db_size;
1084 * This is only a guess -- if the dbuf is dirty
1085 * in a previous txg, we don't know how much
1086 * space it will use on disk yet. We should
1087 * really have the struct_rwlock to access
1088 * db_blkptr, but since this is just a guess,
1089 * it's OK if we get an odd answer.
1091 dnode_willuse_space(dn, -willfree, tx);
1094 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1095 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1096 drop_struct_lock = TRUE;
1099 if (db->db_level == 0) {
1100 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1101 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1104 if (db->db_level+1 < dn->dn_nlevels) {
1105 dmu_buf_impl_t *parent = db->db_parent;
1106 dbuf_dirty_record_t *di;
1107 int parent_held = FALSE;
1109 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1110 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1112 parent = dbuf_hold_level(dn, db->db_level+1,
1113 db->db_blkid >> epbs, FTAG);
1116 if (drop_struct_lock)
1117 rw_exit(&dn->dn_struct_rwlock);
1118 ASSERT3U(db->db_level+1, ==, parent->db_level);
1119 di = dbuf_dirty(parent, tx);
1121 dbuf_rele(parent, FTAG);
1123 mutex_enter(&db->db_mtx);
1124 /* possible race with dbuf_undirty() */
1125 if (db->db_last_dirty == dr ||
1126 dn->dn_object == DMU_META_DNODE_OBJECT) {
1127 mutex_enter(&di->dt.di.dr_mtx);
1128 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1129 ASSERT(!list_link_active(&dr->dr_dirty_node));
1130 list_insert_tail(&di->dt.di.dr_children, dr);
1131 mutex_exit(&di->dt.di.dr_mtx);
1134 mutex_exit(&db->db_mtx);
1136 ASSERT(db->db_level+1 == dn->dn_nlevels);
1137 ASSERT(db->db_blkid < dn->dn_nblkptr);
1138 ASSERT(db->db_parent == NULL ||
1139 db->db_parent == db->db_dnode->dn_dbuf);
1140 mutex_enter(&dn->dn_mtx);
1141 ASSERT(!list_link_active(&dr->dr_dirty_node));
1142 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1143 mutex_exit(&dn->dn_mtx);
1144 if (drop_struct_lock)
1145 rw_exit(&dn->dn_struct_rwlock);
1148 dnode_setdirty(dn, tx);
1153 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1155 dnode_t *dn = db->db_dnode;
1156 uint64_t txg = tx->tx_txg;
1157 dbuf_dirty_record_t *dr, **drp;
1160 ASSERT(db->db_blkid != DB_BONUS_BLKID);
1162 mutex_enter(&db->db_mtx);
1165 * If this buffer is not dirty, we're done.
1167 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1168 if (dr->dr_txg <= txg)
1170 if (dr == NULL || dr->dr_txg < txg) {
1171 mutex_exit(&db->db_mtx);
1174 ASSERT(dr->dr_txg == txg);
1177 * If this buffer is currently held, we cannot undirty
1178 * it, since one of the current holders may be in the
1179 * middle of an update. Note that users of dbuf_undirty()
1180 * should not place a hold on the dbuf before the call.
1182 if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
1183 mutex_exit(&db->db_mtx);
1184 /* Make sure we don't toss this buffer at sync phase */
1185 mutex_enter(&dn->dn_mtx);
1186 dnode_clear_range(dn, db->db_blkid, 1, tx);
1187 mutex_exit(&dn->dn_mtx);
1191 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1193 ASSERT(db->db.db_size != 0);
1195 /* XXX would be nice to fix up dn_towrite_space[] */
1199 if (dr->dr_parent) {
1200 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1201 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1202 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1203 } else if (db->db_level+1 == dn->dn_nlevels) {
1204 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
1205 mutex_enter(&dn->dn_mtx);
1206 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
1207 mutex_exit(&dn->dn_mtx);
1210 if (db->db_level == 0) {
1211 if (db->db_state != DB_NOFILL) {
1212 dbuf_unoverride(dr);
1214 ASSERT(db->db_buf != NULL);
1215 ASSERT(dr->dt.dl.dr_data != NULL);
1216 if (dr->dt.dl.dr_data != db->db_buf)
1217 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
1221 ASSERT(db->db_buf != NULL);
1222 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
1223 mutex_destroy(&dr->dt.di.dr_mtx);
1224 list_destroy(&dr->dt.di.dr_children);
1226 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1228 ASSERT(db->db_dirtycnt > 0);
1229 db->db_dirtycnt -= 1;
1231 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1232 arc_buf_t *buf = db->db_buf;
1234 ASSERT(arc_released(buf));
1235 dbuf_set_data(db, NULL);
1236 VERIFY(arc_buf_remove_ref(buf, db) == 1);
1241 mutex_exit(&db->db_mtx);
1245 #pragma weak dmu_buf_will_dirty = dbuf_will_dirty
1247 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1249 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1251 ASSERT(tx->tx_txg != 0);
1252 ASSERT(!refcount_is_zero(&db->db_holds));
1254 if (RW_WRITE_HELD(&db->db_dnode->dn_struct_rwlock))
1255 rf |= DB_RF_HAVESTRUCT;
1256 (void) dbuf_read(db, NULL, rf);
1257 (void) dbuf_dirty(db, tx);
1261 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1263 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1265 db->db_state = DB_NOFILL;
1267 dmu_buf_will_fill(db_fake, tx);
1271 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1273 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1275 ASSERT(db->db_blkid != DB_BONUS_BLKID);
1276 ASSERT(tx->tx_txg != 0);
1277 ASSERT(db->db_level == 0);
1278 ASSERT(!refcount_is_zero(&db->db_holds));
1280 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1281 dmu_tx_private_ok(tx));
1284 (void) dbuf_dirty(db, tx);
1287 #pragma weak dmu_buf_fill_done = dbuf_fill_done
1290 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1292 mutex_enter(&db->db_mtx);
1295 if (db->db_state == DB_FILL) {
1296 if (db->db_level == 0 && db->db_freed_in_flight) {
1297 ASSERT(db->db_blkid != DB_BONUS_BLKID);
1298 /* we were freed while filling */
1299 /* XXX dbuf_undirty? */
1300 bzero(db->db.db_data, db->db.db_size);
1301 db->db_freed_in_flight = FALSE;
1303 db->db_state = DB_CACHED;
1304 cv_broadcast(&db->db_changed);
1306 mutex_exit(&db->db_mtx);
1310 * Directly assign a provided arc buf to a given dbuf if it's not referenced
1311 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
1314 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
1316 ASSERT(!refcount_is_zero(&db->db_holds));
1317 ASSERT(db->db_dnode->dn_object != DMU_META_DNODE_OBJECT);
1318 ASSERT(db->db_blkid != DB_BONUS_BLKID);
1319 ASSERT(db->db_level == 0);
1320 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
1321 ASSERT(buf != NULL);
1322 ASSERT(arc_buf_size(buf) == db->db.db_size);
1323 ASSERT(tx->tx_txg != 0);
1325 arc_return_buf(buf, db);
1326 ASSERT(arc_released(buf));
1328 mutex_enter(&db->db_mtx);
1330 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1331 cv_wait(&db->db_changed, &db->db_mtx);
1333 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
1335 if (db->db_state == DB_CACHED &&
1336 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
1337 mutex_exit(&db->db_mtx);
1338 (void) dbuf_dirty(db, tx);
1339 bcopy(buf->b_data, db->db.db_data, db->db.db_size);
1340 VERIFY(arc_buf_remove_ref(buf, db) == 1);
1344 if (db->db_state == DB_CACHED) {
1345 dbuf_dirty_record_t *dr = db->db_last_dirty;
1347 ASSERT(db->db_buf != NULL);
1348 if (dr != NULL && dr->dr_txg == tx->tx_txg) {
1349 ASSERT(dr->dt.dl.dr_data == db->db_buf);
1350 if (!arc_released(db->db_buf)) {
1351 ASSERT(dr->dt.dl.dr_override_state ==
1353 arc_release(db->db_buf, db);
1355 dr->dt.dl.dr_data = buf;
1356 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
1357 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
1358 arc_release(db->db_buf, db);
1359 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
1363 ASSERT(db->db_buf == NULL);
1364 dbuf_set_data(db, buf);
1365 db->db_state = DB_FILL;
1366 mutex_exit(&db->db_mtx);
1367 (void) dbuf_dirty(db, tx);
1368 dbuf_fill_done(db, tx);
1372 * "Clear" the contents of this dbuf. This will mark the dbuf
1373 * EVICTING and clear *most* of its references. Unfortunetely,
1374 * when we are not holding the dn_dbufs_mtx, we can't clear the
1375 * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
1376 * in this case. For callers from the DMU we will usually see:
1377 * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy()
1378 * For the arc callback, we will usually see:
1379 * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
1380 * Sometimes, though, we will get a mix of these two:
1381 * DMU: dbuf_clear()->arc_buf_evict()
1382 * ARC: dbuf_do_evict()->dbuf_destroy()
1385 dbuf_clear(dmu_buf_impl_t *db)
1387 dnode_t *dn = db->db_dnode;
1388 dmu_buf_impl_t *parent = db->db_parent;
1389 dmu_buf_impl_t *dndb = dn->dn_dbuf;
1390 int dbuf_gone = FALSE;
1392 ASSERT(MUTEX_HELD(&db->db_mtx));
1393 ASSERT(refcount_is_zero(&db->db_holds));
1395 dbuf_evict_user(db);
1397 if (db->db_state == DB_CACHED) {
1398 ASSERT(db->db.db_data != NULL);
1399 if (db->db_blkid == DB_BONUS_BLKID) {
1400 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1401 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1403 db->db.db_data = NULL;
1404 db->db_state = DB_UNCACHED;
1407 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
1408 ASSERT(db->db_data_pending == NULL);
1410 db->db_state = DB_EVICTING;
1411 db->db_blkptr = NULL;
1413 if (db->db_blkid != DB_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1414 list_remove(&dn->dn_dbufs, db);
1416 db->db_dnode = NULL;
1420 dbuf_gone = arc_buf_evict(db->db_buf);
1423 mutex_exit(&db->db_mtx);
1426 * If this dbuf is referened from an indirect dbuf,
1427 * decrement the ref count on the indirect dbuf.
1429 if (parent && parent != dndb)
1430 dbuf_rele(parent, db);
1434 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1435 dmu_buf_impl_t **parentp, blkptr_t **bpp)
1442 ASSERT(blkid != DB_BONUS_BLKID);
1444 if (dn->dn_phys->dn_nlevels == 0)
1447 nlevels = dn->dn_phys->dn_nlevels;
1449 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1451 ASSERT3U(level * epbs, <, 64);
1452 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1453 if (level >= nlevels ||
1454 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
1455 /* the buffer has no parent yet */
1457 } else if (level < nlevels-1) {
1458 /* this block is referenced from an indirect block */
1459 int err = dbuf_hold_impl(dn, level+1,
1460 blkid >> epbs, fail_sparse, NULL, parentp);
1463 err = dbuf_read(*parentp, NULL,
1464 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1466 dbuf_rele(*parentp, NULL);
1470 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1471 (blkid & ((1ULL << epbs) - 1));
1474 /* the block is referenced from the dnode */
1475 ASSERT3U(level, ==, nlevels-1);
1476 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1477 blkid < dn->dn_phys->dn_nblkptr);
1479 dbuf_add_ref(dn->dn_dbuf, NULL);
1480 *parentp = dn->dn_dbuf;
1482 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1487 static dmu_buf_impl_t *
1488 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1489 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1491 objset_impl_t *os = dn->dn_objset;
1492 dmu_buf_impl_t *db, *odb;
1494 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1495 ASSERT(dn->dn_type != DMU_OT_NONE);
1497 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP);
1500 db->db.db_object = dn->dn_object;
1501 db->db_level = level;
1502 db->db_blkid = blkid;
1503 db->db_last_dirty = NULL;
1504 db->db_dirtycnt = 0;
1506 db->db_parent = parent;
1507 db->db_blkptr = blkptr;
1509 db->db_user_ptr = NULL;
1510 db->db_user_data_ptr_ptr = NULL;
1511 db->db_evict_func = NULL;
1512 db->db_immediate_evict = 0;
1513 db->db_freed_in_flight = 0;
1515 if (blkid == DB_BONUS_BLKID) {
1516 ASSERT3P(parent, ==, dn->dn_dbuf);
1517 db->db.db_size = DN_MAX_BONUSLEN -
1518 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1519 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1520 db->db.db_offset = DB_BONUS_BLKID;
1521 db->db_state = DB_UNCACHED;
1522 /* the bonus dbuf is not placed in the hash table */
1523 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1527 db->db_level ? 1<<dn->dn_indblkshift : dn->dn_datablksz;
1528 db->db.db_size = blocksize;
1529 db->db.db_offset = db->db_blkid * blocksize;
1533 * Hold the dn_dbufs_mtx while we get the new dbuf
1534 * in the hash table *and* added to the dbufs list.
1535 * This prevents a possible deadlock with someone
1536 * trying to look up this dbuf before its added to the
1539 mutex_enter(&dn->dn_dbufs_mtx);
1540 db->db_state = DB_EVICTING;
1541 if ((odb = dbuf_hash_insert(db)) != NULL) {
1542 /* someone else inserted it first */
1543 kmem_cache_free(dbuf_cache, db);
1544 mutex_exit(&dn->dn_dbufs_mtx);
1547 list_insert_head(&dn->dn_dbufs, db);
1548 db->db_state = DB_UNCACHED;
1549 mutex_exit(&dn->dn_dbufs_mtx);
1550 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1552 if (parent && parent != dn->dn_dbuf)
1553 dbuf_add_ref(parent, db);
1555 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1556 refcount_count(&dn->dn_holds) > 0);
1557 (void) refcount_add(&dn->dn_holds, db);
1559 dprintf_dbuf(db, "db=%p\n", db);
1565 dbuf_do_evict(void *private)
1567 arc_buf_t *buf = private;
1568 dmu_buf_impl_t *db = buf->b_private;
1570 if (!MUTEX_HELD(&db->db_mtx))
1571 mutex_enter(&db->db_mtx);
1573 ASSERT(refcount_is_zero(&db->db_holds));
1575 if (db->db_state != DB_EVICTING) {
1576 ASSERT(db->db_state == DB_CACHED);
1581 mutex_exit(&db->db_mtx);
1588 dbuf_destroy(dmu_buf_impl_t *db)
1590 ASSERT(refcount_is_zero(&db->db_holds));
1592 if (db->db_blkid != DB_BONUS_BLKID) {
1594 * If this dbuf is still on the dn_dbufs list,
1595 * remove it from that list.
1598 dnode_t *dn = db->db_dnode;
1600 mutex_enter(&dn->dn_dbufs_mtx);
1601 list_remove(&dn->dn_dbufs, db);
1602 mutex_exit(&dn->dn_dbufs_mtx);
1605 db->db_dnode = NULL;
1607 dbuf_hash_remove(db);
1609 db->db_parent = NULL;
1612 ASSERT(!list_link_active(&db->db_link));
1613 ASSERT(db->db.db_data == NULL);
1614 ASSERT(db->db_hash_next == NULL);
1615 ASSERT(db->db_blkptr == NULL);
1616 ASSERT(db->db_data_pending == NULL);
1618 kmem_cache_free(dbuf_cache, db);
1619 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1623 dbuf_prefetch(dnode_t *dn, uint64_t blkid)
1625 dmu_buf_impl_t *db = NULL;
1626 blkptr_t *bp = NULL;
1628 ASSERT(blkid != DB_BONUS_BLKID);
1629 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1631 if (dnode_block_freed(dn, blkid))
1634 /* dbuf_find() returns with db_mtx held */
1635 if (db = dbuf_find(dn, 0, blkid)) {
1636 if (refcount_count(&db->db_holds) > 0) {
1638 * This dbuf is active. We assume that it is
1639 * already CACHED, or else about to be either
1642 mutex_exit(&db->db_mtx);
1645 mutex_exit(&db->db_mtx);
1649 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) {
1650 if (bp && !BP_IS_HOLE(bp)) {
1652 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
1654 zb.zb_objset = dn->dn_objset->os_dsl_dataset ?
1655 dn->dn_objset->os_dsl_dataset->ds_object : 0;
1656 zb.zb_object = dn->dn_object;
1658 zb.zb_blkid = blkid;
1663 pbuf = dn->dn_objset->os_phys_buf;
1665 (void) arc_read(NULL, dn->dn_objset->os_spa,
1666 bp, pbuf, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
1667 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1671 dbuf_rele(db, NULL);
1676 * Returns with db_holds incremented, and db_mtx not held.
1677 * Note: dn_struct_rwlock must be held.
1680 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
1681 void *tag, dmu_buf_impl_t **dbp)
1683 dmu_buf_impl_t *db, *parent = NULL;
1685 ASSERT(blkid != DB_BONUS_BLKID);
1686 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1687 ASSERT3U(dn->dn_nlevels, >, level);
1691 /* dbuf_find() returns with db_mtx held */
1692 db = dbuf_find(dn, level, blkid);
1695 blkptr_t *bp = NULL;
1698 ASSERT3P(parent, ==, NULL);
1699 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp);
1701 if (err == 0 && bp && BP_IS_HOLE(bp))
1705 dbuf_rele(parent, NULL);
1709 if (err && err != ENOENT)
1711 db = dbuf_create(dn, level, blkid, parent, bp);
1714 if (db->db_buf && refcount_is_zero(&db->db_holds)) {
1715 arc_buf_add_ref(db->db_buf, db);
1716 if (db->db_buf->b_data == NULL) {
1719 dbuf_rele(parent, NULL);
1724 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data);
1727 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf));
1730 * If this buffer is currently syncing out, and we are are
1731 * still referencing it from db_data, we need to make a copy
1732 * of it in case we decide we want to dirty it again in this txg.
1734 if (db->db_level == 0 && db->db_blkid != DB_BONUS_BLKID &&
1735 dn->dn_object != DMU_META_DNODE_OBJECT &&
1736 db->db_state == DB_CACHED && db->db_data_pending) {
1737 dbuf_dirty_record_t *dr = db->db_data_pending;
1739 if (dr->dt.dl.dr_data == db->db_buf) {
1740 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
1743 arc_buf_alloc(db->db_dnode->dn_objset->os_spa,
1744 db->db.db_size, db, type));
1745 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data,
1750 (void) refcount_add(&db->db_holds, tag);
1751 dbuf_update_data(db);
1753 mutex_exit(&db->db_mtx);
1755 /* NOTE: we can't rele the parent until after we drop the db_mtx */
1757 dbuf_rele(parent, NULL);
1759 ASSERT3P(db->db_dnode, ==, dn);
1760 ASSERT3U(db->db_blkid, ==, blkid);
1761 ASSERT3U(db->db_level, ==, level);
1768 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
1771 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
1772 return (err ? NULL : db);
1776 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
1779 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
1780 return (err ? NULL : db);
1784 dbuf_create_bonus(dnode_t *dn)
1786 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
1788 ASSERT(dn->dn_bonus == NULL);
1789 dn->dn_bonus = dbuf_create(dn, 0, DB_BONUS_BLKID, dn->dn_dbuf, NULL);
1792 #pragma weak dmu_buf_add_ref = dbuf_add_ref
1794 dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
1796 int64_t holds = refcount_add(&db->db_holds, tag);
1800 #pragma weak dmu_buf_rele = dbuf_rele
1802 dbuf_rele(dmu_buf_impl_t *db, void *tag)
1806 mutex_enter(&db->db_mtx);
1809 holds = refcount_remove(&db->db_holds, tag);
1813 * We can't freeze indirects if there is a possibility that they
1814 * may be modified in the current syncing context.
1816 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
1817 arc_buf_freeze(db->db_buf);
1819 if (holds == db->db_dirtycnt &&
1820 db->db_level == 0 && db->db_immediate_evict)
1821 dbuf_evict_user(db);
1824 if (db->db_blkid == DB_BONUS_BLKID) {
1825 mutex_exit(&db->db_mtx);
1826 dnode_rele(db->db_dnode, db);
1827 } else if (db->db_buf == NULL) {
1829 * This is a special case: we never associated this
1830 * dbuf with any data allocated from the ARC.
1832 ASSERT(db->db_state == DB_UNCACHED ||
1833 db->db_state == DB_NOFILL);
1835 } else if (arc_released(db->db_buf)) {
1836 arc_buf_t *buf = db->db_buf;
1838 * This dbuf has anonymous data associated with it.
1840 dbuf_set_data(db, NULL);
1841 VERIFY(arc_buf_remove_ref(buf, db) == 1);
1844 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 0);
1845 if (!DBUF_IS_CACHEABLE(db))
1848 mutex_exit(&db->db_mtx);
1851 mutex_exit(&db->db_mtx);
1855 #pragma weak dmu_buf_refcount = dbuf_refcount
1857 dbuf_refcount(dmu_buf_impl_t *db)
1859 return (refcount_count(&db->db_holds));
1863 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
1864 dmu_buf_evict_func_t *evict_func)
1866 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
1867 user_data_ptr_ptr, evict_func));
1871 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
1872 dmu_buf_evict_func_t *evict_func)
1874 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1876 db->db_immediate_evict = TRUE;
1877 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
1878 user_data_ptr_ptr, evict_func));
1882 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr,
1883 void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func)
1885 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1886 ASSERT(db->db_level == 0);
1888 ASSERT((user_ptr == NULL) == (evict_func == NULL));
1890 mutex_enter(&db->db_mtx);
1892 if (db->db_user_ptr == old_user_ptr) {
1893 db->db_user_ptr = user_ptr;
1894 db->db_user_data_ptr_ptr = user_data_ptr_ptr;
1895 db->db_evict_func = evict_func;
1897 dbuf_update_data(db);
1899 old_user_ptr = db->db_user_ptr;
1902 mutex_exit(&db->db_mtx);
1903 return (old_user_ptr);
1907 dmu_buf_get_user(dmu_buf_t *db_fake)
1909 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1910 ASSERT(!refcount_is_zero(&db->db_holds));
1912 return (db->db_user_ptr);
1916 dmu_buf_freeable(dmu_buf_t *dbuf)
1918 boolean_t res = B_FALSE;
1919 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
1922 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
1923 db->db_blkptr->blk_birth);
1929 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
1931 /* ASSERT(dmu_tx_is_syncing(tx) */
1932 ASSERT(MUTEX_HELD(&db->db_mtx));
1934 if (db->db_blkptr != NULL)
1937 if (db->db_level == dn->dn_phys->dn_nlevels-1) {
1939 * This buffer was allocated at a time when there was
1940 * no available blkptrs from the dnode, or it was
1941 * inappropriate to hook it in (i.e., nlevels mis-match).
1943 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr);
1944 ASSERT(db->db_parent == NULL);
1945 db->db_parent = dn->dn_dbuf;
1946 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid];
1949 dmu_buf_impl_t *parent = db->db_parent;
1950 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
1952 ASSERT(dn->dn_phys->dn_nlevels > 1);
1953 if (parent == NULL) {
1954 mutex_exit(&db->db_mtx);
1955 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1956 (void) dbuf_hold_impl(dn, db->db_level+1,
1957 db->db_blkid >> epbs, FALSE, db, &parent);
1958 rw_exit(&dn->dn_struct_rwlock);
1959 mutex_enter(&db->db_mtx);
1960 db->db_parent = parent;
1962 db->db_blkptr = (blkptr_t *)parent->db.db_data +
1963 (db->db_blkid & ((1ULL << epbs) - 1));
1969 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
1971 dmu_buf_impl_t *db = dr->dr_dbuf;
1972 dnode_t *dn = db->db_dnode;
1975 ASSERT(dmu_tx_is_syncing(tx));
1977 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
1979 mutex_enter(&db->db_mtx);
1981 ASSERT(db->db_level > 0);
1984 if (db->db_buf == NULL) {
1985 mutex_exit(&db->db_mtx);
1986 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
1987 mutex_enter(&db->db_mtx);
1989 ASSERT3U(db->db_state, ==, DB_CACHED);
1990 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
1991 ASSERT(db->db_buf != NULL);
1993 dbuf_check_blkptr(dn, db);
1995 db->db_data_pending = dr;
1997 mutex_exit(&db->db_mtx);
1998 dbuf_write(dr, db->db_buf, tx);
2001 mutex_enter(&dr->dt.di.dr_mtx);
2002 dbuf_sync_list(&dr->dt.di.dr_children, tx);
2003 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2004 mutex_exit(&dr->dt.di.dr_mtx);
2009 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2011 arc_buf_t **datap = &dr->dt.dl.dr_data;
2012 dmu_buf_impl_t *db = dr->dr_dbuf;
2013 dnode_t *dn = db->db_dnode;
2014 objset_impl_t *os = dn->dn_objset;
2015 uint64_t txg = tx->tx_txg;
2017 ASSERT(dmu_tx_is_syncing(tx));
2019 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2021 mutex_enter(&db->db_mtx);
2023 * To be synced, we must be dirtied. But we
2024 * might have been freed after the dirty.
2026 if (db->db_state == DB_UNCACHED) {
2027 /* This buffer has been freed since it was dirtied */
2028 ASSERT(db->db.db_data == NULL);
2029 } else if (db->db_state == DB_FILL) {
2030 /* This buffer was freed and is now being re-filled */
2031 ASSERT(db->db.db_data != dr->dt.dl.dr_data);
2033 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL);
2038 * If this is a bonus buffer, simply copy the bonus data into the
2039 * dnode. It will be written out when the dnode is synced (and it
2040 * will be synced, since it must have been dirty for dbuf_sync to
2043 if (db->db_blkid == DB_BONUS_BLKID) {
2044 dbuf_dirty_record_t **drp;
2046 ASSERT(*datap != NULL);
2047 ASSERT3U(db->db_level, ==, 0);
2048 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
2049 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
2050 if (*datap != db->db.db_data) {
2051 zio_buf_free(*datap, DN_MAX_BONUSLEN);
2052 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
2054 db->db_data_pending = NULL;
2055 drp = &db->db_last_dirty;
2057 drp = &(*drp)->dr_next;
2058 ASSERT(dr->dr_next == NULL);
2060 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2061 ASSERT(db->db_dirtycnt > 0);
2062 db->db_dirtycnt -= 1;
2063 mutex_exit(&db->db_mtx);
2064 dbuf_rele(db, (void *)(uintptr_t)txg);
2069 * This function may have dropped the db_mtx lock allowing a dmu_sync
2070 * operation to sneak in. As a result, we need to ensure that we
2071 * don't check the dr_override_state until we have returned from
2072 * dbuf_check_blkptr.
2074 dbuf_check_blkptr(dn, db);
2077 * If this buffer is in the middle of an immdiate write,
2078 * wait for the synchronous IO to complete.
2080 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
2081 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
2082 cv_wait(&db->db_changed, &db->db_mtx);
2083 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
2087 * If this dbuf has already been written out via an immediate write,
2088 * just complete the write by copying over the new block pointer and
2089 * updating the accounting via the write-completion functions.
2091 if (dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
2094 zio_fake.io_private = &db;
2095 zio_fake.io_error = 0;
2096 zio_fake.io_bp = db->db_blkptr;
2097 zio_fake.io_bp_orig = *db->db_blkptr;
2098 zio_fake.io_txg = txg;
2099 zio_fake.io_flags = 0;
2101 *db->db_blkptr = dr->dt.dl.dr_overridden_by;
2102 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
2103 db->db_data_pending = dr;
2104 dr->dr_zio = &zio_fake;
2105 mutex_exit(&db->db_mtx);
2107 ASSERT(!DVA_EQUAL(BP_IDENTITY(zio_fake.io_bp),
2108 BP_IDENTITY(&zio_fake.io_bp_orig)) ||
2109 BP_IS_HOLE(zio_fake.io_bp));
2111 if (BP_IS_OLDER(&zio_fake.io_bp_orig, txg))
2112 (void) dsl_dataset_block_kill(os->os_dsl_dataset,
2113 &zio_fake.io_bp_orig, dn->dn_zio, tx);
2115 dbuf_write_ready(&zio_fake, db->db_buf, db);
2116 dbuf_write_done(&zio_fake, db->db_buf, db);
2121 if (db->db_state != DB_NOFILL &&
2122 dn->dn_object != DMU_META_DNODE_OBJECT &&
2123 refcount_count(&db->db_holds) > 1 &&
2124 *datap == db->db_buf) {
2126 * If this buffer is currently "in use" (i.e., there
2127 * are active holds and db_data still references it),
2128 * then make a copy before we start the write so that
2129 * any modifications from the open txg will not leak
2132 * NOTE: this copy does not need to be made for
2133 * objects only modified in the syncing context (e.g.
2134 * DNONE_DNODE blocks).
2136 int blksz = arc_buf_size(*datap);
2137 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2138 *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
2139 bcopy(db->db.db_data, (*datap)->b_data, blksz);
2141 db->db_data_pending = dr;
2143 mutex_exit(&db->db_mtx);
2145 dbuf_write(dr, *datap, tx);
2147 ASSERT(!list_link_active(&dr->dr_dirty_node));
2148 if (dn->dn_object == DMU_META_DNODE_OBJECT)
2149 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr);
2151 zio_nowait(dr->dr_zio);
2155 dbuf_sync_list(list_t *list, dmu_tx_t *tx)
2157 dbuf_dirty_record_t *dr;
2159 while (dr = list_head(list)) {
2160 if (dr->dr_zio != NULL) {
2162 * If we find an already initialized zio then we
2163 * are processing the meta-dnode, and we have finished.
2164 * The dbufs for all dnodes are put back on the list
2165 * during processing, so that we can zio_wait()
2166 * these IOs after initiating all child IOs.
2168 ASSERT3U(dr->dr_dbuf->db.db_object, ==,
2169 DMU_META_DNODE_OBJECT);
2172 list_remove(list, dr);
2173 if (dr->dr_dbuf->db_level > 0)
2174 dbuf_sync_indirect(dr, tx);
2176 dbuf_sync_leaf(dr, tx);
2181 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
2183 dmu_buf_impl_t *db = dr->dr_dbuf;
2184 dnode_t *dn = db->db_dnode;
2185 objset_impl_t *os = dn->dn_objset;
2186 dmu_buf_impl_t *parent = db->db_parent;
2187 uint64_t txg = tx->tx_txg;
2189 writeprops_t wp = { 0 };
2192 if (!BP_IS_HOLE(db->db_blkptr) &&
2193 (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE)) {
2195 * Private object buffers are released here rather
2196 * than in dbuf_dirty() since they are only modified
2197 * in the syncing context and we don't want the
2198 * overhead of making multiple copies of the data.
2200 arc_release(data, db);
2201 } else if (db->db_state != DB_NOFILL) {
2202 ASSERT(arc_released(data));
2203 /* XXX why do we need to thaw here? */
2207 if (parent != dn->dn_dbuf) {
2208 ASSERT(parent && parent->db_data_pending);
2209 ASSERT(db->db_level == parent->db_level-1);
2210 ASSERT(arc_released(parent->db_buf));
2211 zio = parent->db_data_pending->dr_zio;
2213 ASSERT(db->db_level == dn->dn_phys->dn_nlevels-1);
2214 ASSERT3P(db->db_blkptr, ==,
2215 &dn->dn_phys->dn_blkptr[db->db_blkid]);
2219 ASSERT(db->db_level == 0 || data == db->db_buf);
2220 ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
2223 zb.zb_objset = os->os_dsl_dataset ? os->os_dsl_dataset->ds_object : 0;
2224 zb.zb_object = db->db.db_object;
2225 zb.zb_level = db->db_level;
2226 zb.zb_blkid = db->db_blkid;
2228 wp.wp_type = dn->dn_type;
2229 wp.wp_level = db->db_level;
2230 wp.wp_copies = os->os_copies;
2231 wp.wp_dncompress = dn->dn_compress;
2232 wp.wp_oscompress = os->os_compress;
2233 wp.wp_dnchecksum = dn->dn_checksum;
2234 wp.wp_oschecksum = os->os_checksum;
2236 if (BP_IS_OLDER(db->db_blkptr, txg))
2237 (void) dsl_dataset_block_kill(
2238 os->os_dsl_dataset, db->db_blkptr, zio, tx);
2240 if (db->db_state == DB_NOFILL) {
2241 zio_prop_t zp = { 0 };
2243 write_policy(os->os_spa, &wp, &zp);
2244 dr->dr_zio = zio_write(zio, os->os_spa,
2245 txg, db->db_blkptr, NULL,
2246 db->db.db_size, &zp, dbuf_skip_write_ready,
2247 dbuf_skip_write_done, db, ZIO_PRIORITY_ASYNC_WRITE,
2248 ZIO_FLAG_MUSTSUCCEED, &zb);
2250 dr->dr_zio = arc_write(zio, os->os_spa, &wp,
2251 DBUF_IS_L2CACHEABLE(db), txg, db->db_blkptr,
2252 data, dbuf_write_ready, dbuf_write_done, db,
2253 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2257 /* wrapper function for dbuf_write_ready bypassing ARC */
2259 dbuf_skip_write_ready(zio_t *zio)
2261 blkptr_t *bp = zio->io_bp;
2263 if (!BP_IS_GANG(bp))
2264 zio_skip_write(zio);
2266 dbuf_write_ready(zio, NULL, zio->io_private);
2269 /* wrapper function for dbuf_write_done bypassing ARC */
2271 dbuf_skip_write_done(zio_t *zio)
2273 dbuf_write_done(zio, NULL, zio->io_private);
2278 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
2280 dmu_buf_impl_t *db = vdb;
2281 dnode_t *dn = db->db_dnode;
2282 objset_impl_t *os = dn->dn_objset;
2283 blkptr_t *bp = zio->io_bp;
2284 blkptr_t *bp_orig = &zio->io_bp_orig;
2286 int old_size, new_size, i;
2288 ASSERT(db->db_blkptr == bp);
2290 dprintf_dbuf_bp(db, bp_orig, "bp_orig: %s", "");
2292 old_size = bp_get_dasize(os->os_spa, bp_orig);
2293 new_size = bp_get_dasize(os->os_spa, bp);
2295 dnode_diduse_space(dn, new_size - old_size);
2297 if (BP_IS_HOLE(bp)) {
2298 dsl_dataset_t *ds = os->os_dsl_dataset;
2299 dmu_tx_t *tx = os->os_synctx;
2301 if (bp_orig->blk_birth == tx->tx_txg)
2302 (void) dsl_dataset_block_kill(ds, bp_orig, zio, tx);
2303 ASSERT3U(bp->blk_fill, ==, 0);
2307 ASSERT(BP_GET_TYPE(bp) == dn->dn_type);
2308 ASSERT(BP_GET_LEVEL(bp) == db->db_level);
2310 mutex_enter(&db->db_mtx);
2312 if (db->db_level == 0) {
2313 mutex_enter(&dn->dn_mtx);
2314 if (db->db_blkid > dn->dn_phys->dn_maxblkid)
2315 dn->dn_phys->dn_maxblkid = db->db_blkid;
2316 mutex_exit(&dn->dn_mtx);
2318 if (dn->dn_type == DMU_OT_DNODE) {
2319 dnode_phys_t *dnp = db->db.db_data;
2320 for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
2322 if (dnp->dn_type != DMU_OT_NONE)
2329 blkptr_t *ibp = db->db.db_data;
2330 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2331 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
2332 if (BP_IS_HOLE(ibp))
2334 ASSERT3U(BP_GET_LSIZE(ibp), ==,
2335 db->db_level == 1 ? dn->dn_datablksz :
2336 (1<<dn->dn_phys->dn_indblkshift));
2337 fill += ibp->blk_fill;
2341 bp->blk_fill = fill;
2343 mutex_exit(&db->db_mtx);
2345 if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
2346 ASSERT(DVA_EQUAL(BP_IDENTITY(bp), BP_IDENTITY(bp_orig)));
2348 dsl_dataset_t *ds = os->os_dsl_dataset;
2349 dmu_tx_t *tx = os->os_synctx;
2351 if (bp_orig->blk_birth == tx->tx_txg)
2352 (void) dsl_dataset_block_kill(ds, bp_orig, zio, tx);
2353 dsl_dataset_block_born(ds, bp, tx);
2359 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
2361 dmu_buf_impl_t *db = vdb;
2362 uint64_t txg = zio->io_txg;
2363 dbuf_dirty_record_t **drp, *dr;
2365 ASSERT3U(zio->io_error, ==, 0);
2367 mutex_enter(&db->db_mtx);
2369 drp = &db->db_last_dirty;
2370 while ((dr = *drp) != db->db_data_pending)
2372 ASSERT(!list_link_active(&dr->dr_dirty_node));
2373 ASSERT(dr->dr_txg == txg);
2374 ASSERT(dr->dr_next == NULL);
2377 if (db->db_level == 0) {
2378 ASSERT(db->db_blkid != DB_BONUS_BLKID);
2379 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
2381 if (db->db_state != DB_NOFILL) {
2382 if (dr->dt.dl.dr_data != db->db_buf)
2383 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
2385 else if (!BP_IS_HOLE(db->db_blkptr))
2386 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2388 ASSERT(arc_released(db->db_buf));
2391 dnode_t *dn = db->db_dnode;
2393 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2394 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2395 if (!BP_IS_HOLE(db->db_blkptr)) {
2397 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2398 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
2400 ASSERT3U(dn->dn_phys->dn_maxblkid
2401 >> (db->db_level * epbs), >=, db->db_blkid);
2402 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2404 mutex_destroy(&dr->dt.di.dr_mtx);
2405 list_destroy(&dr->dt.di.dr_children);
2407 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2409 cv_broadcast(&db->db_changed);
2410 ASSERT(db->db_dirtycnt > 0);
2411 db->db_dirtycnt -= 1;
2412 db->db_data_pending = NULL;
2413 mutex_exit(&db->db_mtx);
2415 dprintf_dbuf_bp(db, zio->io_bp, "bp: %s", "");
2417 dbuf_rele(db, (void *)(uintptr_t)txg);