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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
25 #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 #include <sys/sa_impl.h>
40 struct dbuf_hold_impl_data {
41 /* Function arguments */
47 dmu_buf_impl_t **dh_dbp;
49 dmu_buf_impl_t *dh_db;
50 dmu_buf_impl_t *dh_parent;
53 dbuf_dirty_record_t *dh_dr;
54 arc_buf_contents_t dh_type;
58 static void __dbuf_hold_impl_init(struct dbuf_hold_impl_data *dh,
59 dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
60 void *tag, dmu_buf_impl_t **dbp, int depth);
61 static int __dbuf_hold_impl(struct dbuf_hold_impl_data *dh);
63 static void dbuf_destroy(dmu_buf_impl_t *db);
64 static int dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
65 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
68 * Global data structures and functions for the dbuf cache.
70 static kmem_cache_t *dbuf_cache;
74 dbuf_cons(void *vdb, void *unused, int kmflag)
76 dmu_buf_impl_t *db = vdb;
77 bzero(db, sizeof (dmu_buf_impl_t));
79 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
80 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
81 refcount_create(&db->db_holds);
82 list_link_init(&db->db_link);
88 dbuf_dest(void *vdb, void *unused)
90 dmu_buf_impl_t *db = vdb;
91 mutex_destroy(&db->db_mtx);
92 cv_destroy(&db->db_changed);
93 refcount_destroy(&db->db_holds);
97 * dbuf hash table routines
99 static dbuf_hash_table_t dbuf_hash_table;
101 static uint64_t dbuf_hash_count;
104 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
106 uintptr_t osv = (uintptr_t)os;
107 uint64_t crc = -1ULL;
109 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
110 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
111 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
112 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
113 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
114 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
115 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
117 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
122 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
124 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
125 ((dbuf)->db.db_object == (obj) && \
126 (dbuf)->db_objset == (os) && \
127 (dbuf)->db_level == (level) && \
128 (dbuf)->db_blkid == (blkid))
131 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
133 dbuf_hash_table_t *h = &dbuf_hash_table;
134 objset_t *os = dn->dn_objset;
141 hv = DBUF_HASH(os, obj, level, blkid);
142 idx = hv & h->hash_table_mask;
144 mutex_enter(DBUF_HASH_MUTEX(h, idx));
145 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
146 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
147 mutex_enter(&db->db_mtx);
148 if (db->db_state != DB_EVICTING) {
149 mutex_exit(DBUF_HASH_MUTEX(h, idx));
152 mutex_exit(&db->db_mtx);
155 mutex_exit(DBUF_HASH_MUTEX(h, idx));
160 * Insert an entry into the hash table. If there is already an element
161 * equal to elem in the hash table, then the already existing element
162 * will be returned and the new element will not be inserted.
163 * Otherwise returns NULL.
165 static dmu_buf_impl_t *
166 dbuf_hash_insert(dmu_buf_impl_t *db)
168 dbuf_hash_table_t *h = &dbuf_hash_table;
169 objset_t *os = db->db_objset;
170 uint64_t obj = db->db.db_object;
171 int level = db->db_level;
172 uint64_t blkid, hv, idx;
175 blkid = db->db_blkid;
176 hv = DBUF_HASH(os, obj, level, blkid);
177 idx = hv & h->hash_table_mask;
179 mutex_enter(DBUF_HASH_MUTEX(h, idx));
180 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
181 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
182 mutex_enter(&dbf->db_mtx);
183 if (dbf->db_state != DB_EVICTING) {
184 mutex_exit(DBUF_HASH_MUTEX(h, idx));
187 mutex_exit(&dbf->db_mtx);
191 mutex_enter(&db->db_mtx);
192 db->db_hash_next = h->hash_table[idx];
193 h->hash_table[idx] = db;
194 mutex_exit(DBUF_HASH_MUTEX(h, idx));
195 atomic_add_64(&dbuf_hash_count, 1);
201 * Remove an entry from the hash table. This operation will
202 * fail if there are any existing holds on the db.
205 dbuf_hash_remove(dmu_buf_impl_t *db)
207 dbuf_hash_table_t *h = &dbuf_hash_table;
209 dmu_buf_impl_t *dbf, **dbp;
211 hv = DBUF_HASH(db->db_objset, db->db.db_object,
212 db->db_level, db->db_blkid);
213 idx = hv & h->hash_table_mask;
216 * We musn't hold db_mtx to maintin lock ordering:
217 * DBUF_HASH_MUTEX > db_mtx.
219 ASSERT(refcount_is_zero(&db->db_holds));
220 ASSERT(db->db_state == DB_EVICTING);
221 ASSERT(!MUTEX_HELD(&db->db_mtx));
223 mutex_enter(DBUF_HASH_MUTEX(h, idx));
224 dbp = &h->hash_table[idx];
225 while ((dbf = *dbp) != db) {
226 dbp = &dbf->db_hash_next;
229 *dbp = db->db_hash_next;
230 db->db_hash_next = NULL;
231 mutex_exit(DBUF_HASH_MUTEX(h, idx));
232 atomic_add_64(&dbuf_hash_count, -1);
235 static arc_evict_func_t dbuf_do_evict;
238 dbuf_evict_user(dmu_buf_impl_t *db)
240 ASSERT(MUTEX_HELD(&db->db_mtx));
242 if (db->db_level != 0 || db->db_evict_func == NULL)
245 if (db->db_user_data_ptr_ptr)
246 *db->db_user_data_ptr_ptr = db->db.db_data;
247 db->db_evict_func(&db->db, db->db_user_ptr);
248 db->db_user_ptr = NULL;
249 db->db_user_data_ptr_ptr = NULL;
250 db->db_evict_func = NULL;
254 dbuf_is_metadata(dmu_buf_impl_t *db)
256 if (db->db_level > 0) {
259 boolean_t is_metadata;
262 is_metadata = dmu_ot[DB_DNODE(db)->dn_type].ot_metadata;
265 return (is_metadata);
270 dbuf_evict(dmu_buf_impl_t *db)
272 ASSERT(MUTEX_HELD(&db->db_mtx));
273 ASSERT(db->db_buf == NULL);
274 ASSERT(db->db_data_pending == NULL);
283 uint64_t hsize = 1ULL << 16;
284 dbuf_hash_table_t *h = &dbuf_hash_table;
288 * The hash table is big enough to fill all of physical memory
289 * with an average 4K block size. The table will take up
290 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
292 while (hsize * 4096 < physmem * PAGESIZE)
296 h->hash_table_mask = hsize - 1;
297 #if defined(_KERNEL) && defined(HAVE_SPL)
298 /* Large allocations which do not require contiguous pages
299 * should be using vmem_alloc() in the linux kernel */
300 h->hash_table = vmem_zalloc(hsize * sizeof (void *), KM_SLEEP);
302 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
304 if (h->hash_table == NULL) {
305 /* XXX - we should really return an error instead of assert */
306 ASSERT(hsize > (1ULL << 10));
311 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
312 sizeof (dmu_buf_impl_t),
313 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
315 for (i = 0; i < DBUF_MUTEXES; i++)
316 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
322 dbuf_hash_table_t *h = &dbuf_hash_table;
325 for (i = 0; i < DBUF_MUTEXES; i++)
326 mutex_destroy(&h->hash_mutexes[i]);
327 #if defined(_KERNEL) && defined(HAVE_SPL)
328 /* Large allocations which do not require contiguous pages
329 * should be using vmem_free() in the linux kernel */
330 vmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
332 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
334 kmem_cache_destroy(dbuf_cache);
343 dbuf_verify(dmu_buf_impl_t *db)
346 dbuf_dirty_record_t *dr;
348 ASSERT(MUTEX_HELD(&db->db_mtx));
350 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
353 ASSERT(db->db_objset != NULL);
357 ASSERT(db->db_parent == NULL);
358 ASSERT(db->db_blkptr == NULL);
360 ASSERT3U(db->db.db_object, ==, dn->dn_object);
361 ASSERT3P(db->db_objset, ==, dn->dn_objset);
362 ASSERT3U(db->db_level, <, dn->dn_nlevels);
363 ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
364 db->db_blkid == DMU_SPILL_BLKID ||
365 !list_is_empty(&dn->dn_dbufs));
367 if (db->db_blkid == DMU_BONUS_BLKID) {
369 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
370 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID);
371 } else if (db->db_blkid == DMU_SPILL_BLKID) {
373 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
374 ASSERT3U(db->db.db_offset, ==, 0);
376 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
379 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
380 ASSERT(dr->dr_dbuf == db);
382 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
383 ASSERT(dr->dr_dbuf == db);
386 * We can't assert that db_size matches dn_datablksz because it
387 * can be momentarily different when another thread is doing
390 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
391 dr = db->db_data_pending;
393 * It should only be modified in syncing context, so
394 * make sure we only have one copy of the data.
396 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
399 /* verify db->db_blkptr */
401 if (db->db_parent == dn->dn_dbuf) {
402 /* db is pointed to by the dnode */
403 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
404 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
405 ASSERT(db->db_parent == NULL);
407 ASSERT(db->db_parent != NULL);
408 if (db->db_blkid != DMU_SPILL_BLKID)
409 ASSERT3P(db->db_blkptr, ==,
410 &dn->dn_phys->dn_blkptr[db->db_blkid]);
412 /* db is pointed to by an indirect block */
413 ASSERTV(int epb = db->db_parent->db.db_size >>
415 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
416 ASSERT3U(db->db_parent->db.db_object, ==,
419 * dnode_grow_indblksz() can make this fail if we don't
420 * have the struct_rwlock. XXX indblksz no longer
421 * grows. safe to do this now?
423 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
424 ASSERT3P(db->db_blkptr, ==,
425 ((blkptr_t *)db->db_parent->db.db_data +
426 db->db_blkid % epb));
430 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
431 (db->db_buf == NULL || db->db_buf->b_data) &&
432 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID &&
433 db->db_state != DB_FILL && !dn->dn_free_txg) {
435 * If the blkptr isn't set but they have nonzero data,
436 * it had better be dirty, otherwise we'll lose that
437 * data when we evict this buffer.
439 if (db->db_dirtycnt == 0) {
440 ASSERTV(uint64_t *buf = db->db.db_data);
443 for (i = 0; i < db->db.db_size >> 3; i++) {
453 dbuf_update_data(dmu_buf_impl_t *db)
455 ASSERT(MUTEX_HELD(&db->db_mtx));
456 if (db->db_level == 0 && db->db_user_data_ptr_ptr) {
457 ASSERT(!refcount_is_zero(&db->db_holds));
458 *db->db_user_data_ptr_ptr = db->db.db_data;
463 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
465 ASSERT(MUTEX_HELD(&db->db_mtx));
466 ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf));
469 ASSERT(buf->b_data != NULL);
470 db->db.db_data = buf->b_data;
471 if (!arc_released(buf))
472 arc_set_callback(buf, dbuf_do_evict, db);
473 dbuf_update_data(db);
476 db->db.db_data = NULL;
477 if (db->db_state != DB_NOFILL)
478 db->db_state = DB_UNCACHED;
483 * Loan out an arc_buf for read. Return the loaned arc_buf.
486 dbuf_loan_arcbuf(dmu_buf_impl_t *db)
490 mutex_enter(&db->db_mtx);
491 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
492 int blksz = db->db.db_size;
495 mutex_exit(&db->db_mtx);
496 DB_GET_SPA(&spa, db);
497 abuf = arc_loan_buf(spa, blksz);
498 bcopy(db->db.db_data, abuf->b_data, blksz);
501 arc_loan_inuse_buf(abuf, db);
502 dbuf_set_data(db, NULL);
503 mutex_exit(&db->db_mtx);
509 dbuf_whichblock(dnode_t *dn, uint64_t offset)
511 if (dn->dn_datablkshift) {
512 return (offset >> dn->dn_datablkshift);
514 ASSERT3U(offset, <, dn->dn_datablksz);
520 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
522 dmu_buf_impl_t *db = vdb;
524 mutex_enter(&db->db_mtx);
525 ASSERT3U(db->db_state, ==, DB_READ);
527 * All reads are synchronous, so we must have a hold on the dbuf
529 ASSERT(refcount_count(&db->db_holds) > 0);
530 ASSERT(db->db_buf == NULL);
531 ASSERT(db->db.db_data == NULL);
532 if (db->db_level == 0 && db->db_freed_in_flight) {
533 /* we were freed in flight; disregard any error */
534 arc_release(buf, db);
535 bzero(buf->b_data, db->db.db_size);
537 db->db_freed_in_flight = FALSE;
538 dbuf_set_data(db, buf);
539 db->db_state = DB_CACHED;
540 } else if (zio == NULL || zio->io_error == 0) {
541 dbuf_set_data(db, buf);
542 db->db_state = DB_CACHED;
544 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
545 ASSERT3P(db->db_buf, ==, NULL);
546 VERIFY(arc_buf_remove_ref(buf, db) == 1);
547 db->db_state = DB_UNCACHED;
549 cv_broadcast(&db->db_changed);
550 dbuf_rele_and_unlock(db, NULL);
554 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
559 uint32_t aflags = ARC_NOWAIT;
564 ASSERT(!refcount_is_zero(&db->db_holds));
565 /* We need the struct_rwlock to prevent db_blkptr from changing. */
566 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
567 ASSERT(MUTEX_HELD(&db->db_mtx));
568 ASSERT(db->db_state == DB_UNCACHED);
569 ASSERT(db->db_buf == NULL);
571 if (db->db_blkid == DMU_BONUS_BLKID) {
572 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
574 ASSERT3U(bonuslen, <=, db->db.db_size);
575 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
576 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
577 if (bonuslen < DN_MAX_BONUSLEN)
578 bzero(db->db.db_data, DN_MAX_BONUSLEN);
580 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
582 dbuf_update_data(db);
583 db->db_state = DB_CACHED;
584 mutex_exit(&db->db_mtx);
589 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
590 * processes the delete record and clears the bp while we are waiting
591 * for the dn_mtx (resulting in a "no" from block_freed).
593 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
594 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
595 BP_IS_HOLE(db->db_blkptr)))) {
596 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
598 dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa,
599 db->db.db_size, db, type));
601 bzero(db->db.db_data, db->db.db_size);
602 db->db_state = DB_CACHED;
603 *flags |= DB_RF_CACHED;
604 mutex_exit(&db->db_mtx);
608 spa = dn->dn_objset->os_spa;
611 db->db_state = DB_READ;
612 mutex_exit(&db->db_mtx);
614 if (DBUF_IS_L2CACHEABLE(db))
615 aflags |= ARC_L2CACHE;
617 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
618 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
619 db->db.db_object, db->db_level, db->db_blkid);
621 dbuf_add_ref(db, NULL);
622 /* ZIO_FLAG_CANFAIL callers have to check the parent zio's error */
625 pbuf = db->db_parent->db_buf;
627 pbuf = db->db_objset->os_phys_buf;
629 (void) dsl_read(zio, spa, db->db_blkptr, pbuf,
630 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
631 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
633 if (aflags & ARC_CACHED)
634 *flags |= DB_RF_CACHED;
638 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
641 int havepzio = (zio != NULL);
646 * We don't have to hold the mutex to check db_state because it
647 * can't be freed while we have a hold on the buffer.
649 ASSERT(!refcount_is_zero(&db->db_holds));
651 if (db->db_state == DB_NOFILL)
656 if ((flags & DB_RF_HAVESTRUCT) == 0)
657 rw_enter(&dn->dn_struct_rwlock, RW_READER);
659 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
660 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL &&
661 DBUF_IS_CACHEABLE(db);
663 mutex_enter(&db->db_mtx);
664 if (db->db_state == DB_CACHED) {
665 mutex_exit(&db->db_mtx);
667 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
668 db->db.db_size, TRUE);
669 if ((flags & DB_RF_HAVESTRUCT) == 0)
670 rw_exit(&dn->dn_struct_rwlock);
672 } else if (db->db_state == DB_UNCACHED) {
673 spa_t *spa = dn->dn_objset->os_spa;
676 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
677 dbuf_read_impl(db, zio, &flags);
679 /* dbuf_read_impl has dropped db_mtx for us */
682 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
683 db->db.db_size, flags & DB_RF_CACHED);
685 if ((flags & DB_RF_HAVESTRUCT) == 0)
686 rw_exit(&dn->dn_struct_rwlock);
692 mutex_exit(&db->db_mtx);
694 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
695 db->db.db_size, TRUE);
696 if ((flags & DB_RF_HAVESTRUCT) == 0)
697 rw_exit(&dn->dn_struct_rwlock);
700 mutex_enter(&db->db_mtx);
701 if ((flags & DB_RF_NEVERWAIT) == 0) {
702 while (db->db_state == DB_READ ||
703 db->db_state == DB_FILL) {
704 ASSERT(db->db_state == DB_READ ||
705 (flags & DB_RF_HAVESTRUCT) == 0);
706 cv_wait(&db->db_changed, &db->db_mtx);
708 if (db->db_state == DB_UNCACHED)
711 mutex_exit(&db->db_mtx);
714 ASSERT(err || havepzio || db->db_state == DB_CACHED);
719 dbuf_noread(dmu_buf_impl_t *db)
721 ASSERT(!refcount_is_zero(&db->db_holds));
722 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
723 mutex_enter(&db->db_mtx);
724 while (db->db_state == DB_READ || db->db_state == DB_FILL)
725 cv_wait(&db->db_changed, &db->db_mtx);
726 if (db->db_state == DB_UNCACHED) {
727 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
730 ASSERT(db->db_buf == NULL);
731 ASSERT(db->db.db_data == NULL);
732 DB_GET_SPA(&spa, db);
733 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type));
734 db->db_state = DB_FILL;
735 } else if (db->db_state == DB_NOFILL) {
736 dbuf_set_data(db, NULL);
738 ASSERT3U(db->db_state, ==, DB_CACHED);
740 mutex_exit(&db->db_mtx);
744 * This is our just-in-time copy function. It makes a copy of
745 * buffers, that have been modified in a previous transaction
746 * group, before we modify them in the current active group.
748 * This function is used in two places: when we are dirtying a
749 * buffer for the first time in a txg, and when we are freeing
750 * a range in a dnode that includes this buffer.
752 * Note that when we are called from dbuf_free_range() we do
753 * not put a hold on the buffer, we just traverse the active
754 * dbuf list for the dnode.
757 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
759 dbuf_dirty_record_t *dr = db->db_last_dirty;
761 ASSERT(MUTEX_HELD(&db->db_mtx));
762 ASSERT(db->db.db_data != NULL);
763 ASSERT(db->db_level == 0);
764 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT);
767 (dr->dt.dl.dr_data !=
768 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf)))
772 * If the last dirty record for this dbuf has not yet synced
773 * and its referencing the dbuf data, either:
774 * reset the reference to point to a new copy,
775 * or (if there a no active holders)
776 * just null out the current db_data pointer.
778 ASSERT(dr->dr_txg >= txg - 2);
779 if (db->db_blkid == DMU_BONUS_BLKID) {
780 /* Note that the data bufs here are zio_bufs */
781 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
782 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
783 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
784 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
785 int size = db->db.db_size;
786 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
789 DB_GET_SPA(&spa, db);
790 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type);
791 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
793 dbuf_set_data(db, NULL);
798 dbuf_unoverride(dbuf_dirty_record_t *dr)
800 dmu_buf_impl_t *db = dr->dr_dbuf;
801 blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
802 uint64_t txg = dr->dr_txg;
804 ASSERT(MUTEX_HELD(&db->db_mtx));
805 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
806 ASSERT(db->db_level == 0);
808 if (db->db_blkid == DMU_BONUS_BLKID ||
809 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
812 ASSERT(db->db_data_pending != dr);
814 /* free this block */
815 if (!BP_IS_HOLE(bp)) {
818 DB_GET_SPA(&spa, db);
819 zio_free(spa, txg, bp);
821 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
823 * Release the already-written buffer, so we leave it in
824 * a consistent dirty state. Note that all callers are
825 * modifying the buffer, so they will immediately do
826 * another (redundant) arc_release(). Therefore, leave
827 * the buf thawed to save the effort of freezing &
828 * immediately re-thawing it.
830 arc_release(dr->dt.dl.dr_data, db);
834 * Evict (if its unreferenced) or clear (if its referenced) any level-0
835 * data blocks in the free range, so that any future readers will find
836 * empty blocks. Also, if we happen accross any level-1 dbufs in the
837 * range that have not already been marked dirty, mark them dirty so
838 * they stay in memory.
841 dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
843 dmu_buf_impl_t *db, *db_next;
844 uint64_t txg = tx->tx_txg;
845 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
846 uint64_t first_l1 = start >> epbs;
847 uint64_t last_l1 = end >> epbs;
849 if (end > dn->dn_maxblkid && (end != DMU_SPILL_BLKID)) {
850 end = dn->dn_maxblkid;
851 last_l1 = end >> epbs;
853 dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
854 mutex_enter(&dn->dn_dbufs_mtx);
855 for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
856 db_next = list_next(&dn->dn_dbufs, db);
857 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
859 if (db->db_level == 1 &&
860 db->db_blkid >= first_l1 && db->db_blkid <= last_l1) {
861 mutex_enter(&db->db_mtx);
862 if (db->db_last_dirty &&
863 db->db_last_dirty->dr_txg < txg) {
864 dbuf_add_ref(db, FTAG);
865 mutex_exit(&db->db_mtx);
866 dbuf_will_dirty(db, tx);
869 mutex_exit(&db->db_mtx);
873 if (db->db_level != 0)
875 dprintf_dbuf(db, "found buf %s\n", "");
876 if (db->db_blkid < start || db->db_blkid > end)
879 /* found a level 0 buffer in the range */
880 if (dbuf_undirty(db, tx))
883 mutex_enter(&db->db_mtx);
884 if (db->db_state == DB_UNCACHED ||
885 db->db_state == DB_NOFILL ||
886 db->db_state == DB_EVICTING) {
887 ASSERT(db->db.db_data == NULL);
888 mutex_exit(&db->db_mtx);
891 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
892 /* will be handled in dbuf_read_done or dbuf_rele */
893 db->db_freed_in_flight = TRUE;
894 mutex_exit(&db->db_mtx);
897 if (refcount_count(&db->db_holds) == 0) {
902 /* The dbuf is referenced */
904 if (db->db_last_dirty != NULL) {
905 dbuf_dirty_record_t *dr = db->db_last_dirty;
907 if (dr->dr_txg == txg) {
909 * This buffer is "in-use", re-adjust the file
910 * size to reflect that this buffer may
911 * contain new data when we sync.
913 if (db->db_blkid != DMU_SPILL_BLKID &&
914 db->db_blkid > dn->dn_maxblkid)
915 dn->dn_maxblkid = db->db_blkid;
919 * This dbuf is not dirty in the open context.
920 * Either uncache it (if its not referenced in
921 * the open context) or reset its contents to
924 dbuf_fix_old_data(db, txg);
927 /* clear the contents if its cached */
928 if (db->db_state == DB_CACHED) {
929 ASSERT(db->db.db_data != NULL);
930 arc_release(db->db_buf, db);
931 bzero(db->db.db_data, db->db.db_size);
932 arc_buf_freeze(db->db_buf);
935 mutex_exit(&db->db_mtx);
937 mutex_exit(&dn->dn_dbufs_mtx);
941 dbuf_block_freeable(dmu_buf_impl_t *db)
943 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
944 uint64_t birth_txg = 0;
947 * We don't need any locking to protect db_blkptr:
948 * If it's syncing, then db_last_dirty will be set
949 * so we'll ignore db_blkptr.
951 ASSERT(MUTEX_HELD(&db->db_mtx));
952 if (db->db_last_dirty)
953 birth_txg = db->db_last_dirty->dr_txg;
954 else if (db->db_blkptr)
955 birth_txg = db->db_blkptr->blk_birth;
958 * If we don't exist or are in a snapshot, we can't be freed.
959 * Don't pass the bp to dsl_dataset_block_freeable() since we
960 * are holding the db_mtx lock and might deadlock if we are
961 * prefetching a dedup-ed block.
964 return (ds == NULL ||
965 dsl_dataset_block_freeable(ds, NULL, birth_txg));
971 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
973 arc_buf_t *buf, *obuf;
974 int osize = db->db.db_size;
975 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
978 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
983 /* XXX does *this* func really need the lock? */
984 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
987 * This call to dbuf_will_dirty() with the dn_struct_rwlock held
988 * is OK, because there can be no other references to the db
989 * when we are changing its size, so no concurrent DB_FILL can
993 * XXX we should be doing a dbuf_read, checking the return
994 * value and returning that up to our callers
996 dbuf_will_dirty(db, tx);
998 /* create the data buffer for the new block */
999 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type);
1001 /* copy old block data to the new block */
1003 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
1004 /* zero the remainder */
1006 bzero((uint8_t *)buf->b_data + osize, size - osize);
1008 mutex_enter(&db->db_mtx);
1009 dbuf_set_data(db, buf);
1010 VERIFY(arc_buf_remove_ref(obuf, db) == 1);
1011 db->db.db_size = size;
1013 if (db->db_level == 0) {
1014 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
1015 db->db_last_dirty->dt.dl.dr_data = buf;
1017 mutex_exit(&db->db_mtx);
1019 dnode_willuse_space(dn, size-osize, tx);
1024 dbuf_release_bp(dmu_buf_impl_t *db)
1029 DB_GET_OBJSET(&os, db);
1030 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
1031 ASSERT(arc_released(os->os_phys_buf) ||
1032 list_link_active(&os->os_dsl_dataset->ds_synced_link));
1033 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf));
1035 zb.zb_objset = os->os_dsl_dataset ?
1036 os->os_dsl_dataset->ds_object : 0;
1037 zb.zb_object = db->db.db_object;
1038 zb.zb_level = db->db_level;
1039 zb.zb_blkid = db->db_blkid;
1040 (void) arc_release_bp(db->db_buf, db,
1041 db->db_blkptr, os->os_spa, &zb);
1044 dbuf_dirty_record_t *
1045 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1049 dbuf_dirty_record_t **drp, *dr;
1050 int drop_struct_lock = FALSE;
1051 boolean_t do_free_accounting = B_FALSE;
1052 int txgoff = tx->tx_txg & TXG_MASK;
1054 ASSERT(tx->tx_txg != 0);
1055 ASSERT(!refcount_is_zero(&db->db_holds));
1056 DMU_TX_DIRTY_BUF(tx, db);
1061 * Shouldn't dirty a regular buffer in syncing context. Private
1062 * objects may be dirtied in syncing context, but only if they
1063 * were already pre-dirtied in open context.
1065 ASSERT(!dmu_tx_is_syncing(tx) ||
1066 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
1067 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1068 dn->dn_objset->os_dsl_dataset == NULL);
1070 * We make this assert for private objects as well, but after we
1071 * check if we're already dirty. They are allowed to re-dirty
1072 * in syncing context.
1074 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1075 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1076 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1078 mutex_enter(&db->db_mtx);
1080 * XXX make this true for indirects too? The problem is that
1081 * transactions created with dmu_tx_create_assigned() from
1082 * syncing context don't bother holding ahead.
1084 ASSERT(db->db_level != 0 ||
1085 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
1086 db->db_state == DB_NOFILL);
1088 mutex_enter(&dn->dn_mtx);
1090 * Don't set dirtyctx to SYNC if we're just modifying this as we
1091 * initialize the objset.
1093 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
1094 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
1096 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
1097 ASSERT(dn->dn_dirtyctx_firstset == NULL);
1098 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
1100 mutex_exit(&dn->dn_mtx);
1102 if (db->db_blkid == DMU_SPILL_BLKID)
1103 dn->dn_have_spill = B_TRUE;
1106 * If this buffer is already dirty, we're done.
1108 drp = &db->db_last_dirty;
1109 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
1110 db->db.db_object == DMU_META_DNODE_OBJECT);
1111 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
1113 if (dr && dr->dr_txg == tx->tx_txg) {
1116 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
1118 * If this buffer has already been written out,
1119 * we now need to reset its state.
1121 dbuf_unoverride(dr);
1122 if (db->db.db_object != DMU_META_DNODE_OBJECT &&
1123 db->db_state != DB_NOFILL)
1124 arc_buf_thaw(db->db_buf);
1126 mutex_exit(&db->db_mtx);
1131 * Only valid if not already dirty.
1133 ASSERT(dn->dn_object == 0 ||
1134 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1135 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1137 ASSERT3U(dn->dn_nlevels, >, db->db_level);
1138 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
1139 dn->dn_phys->dn_nlevels > db->db_level ||
1140 dn->dn_next_nlevels[txgoff] > db->db_level ||
1141 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
1142 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
1145 * We should only be dirtying in syncing context if it's the
1146 * mos or we're initializing the os or it's a special object.
1147 * However, we are allowed to dirty in syncing context provided
1148 * we already dirtied it in open context. Hence we must make
1149 * this assertion only if we're not already dirty.
1152 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1153 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
1154 ASSERT(db->db.db_size != 0);
1156 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1158 if (db->db_blkid != DMU_BONUS_BLKID) {
1160 * Update the accounting.
1161 * Note: we delay "free accounting" until after we drop
1162 * the db_mtx. This keeps us from grabbing other locks
1163 * (and possibly deadlocking) in bp_get_dsize() while
1164 * also holding the db_mtx.
1166 dnode_willuse_space(dn, db->db.db_size, tx);
1167 do_free_accounting = dbuf_block_freeable(db);
1171 * If this buffer is dirty in an old transaction group we need
1172 * to make a copy of it so that the changes we make in this
1173 * transaction group won't leak out when we sync the older txg.
1175 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP);
1176 list_link_init(&dr->dr_dirty_node);
1177 if (db->db_level == 0) {
1178 void *data_old = db->db_buf;
1180 if (db->db_state != DB_NOFILL) {
1181 if (db->db_blkid == DMU_BONUS_BLKID) {
1182 dbuf_fix_old_data(db, tx->tx_txg);
1183 data_old = db->db.db_data;
1184 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1186 * Release the data buffer from the cache so
1187 * that we can modify it without impacting
1188 * possible other users of this cached data
1189 * block. Note that indirect blocks and
1190 * private objects are not released until the
1191 * syncing state (since they are only modified
1194 arc_release(db->db_buf, db);
1195 dbuf_fix_old_data(db, tx->tx_txg);
1196 data_old = db->db_buf;
1198 ASSERT(data_old != NULL);
1200 dr->dt.dl.dr_data = data_old;
1202 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1203 list_create(&dr->dt.di.dr_children,
1204 sizeof (dbuf_dirty_record_t),
1205 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1208 dr->dr_txg = tx->tx_txg;
1213 * We could have been freed_in_flight between the dbuf_noread
1214 * and dbuf_dirty. We win, as though the dbuf_noread() had
1215 * happened after the free.
1217 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1218 db->db_blkid != DMU_SPILL_BLKID) {
1219 mutex_enter(&dn->dn_mtx);
1220 dnode_clear_range(dn, db->db_blkid, 1, tx);
1221 mutex_exit(&dn->dn_mtx);
1222 db->db_freed_in_flight = FALSE;
1226 * This buffer is now part of this txg
1228 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1229 db->db_dirtycnt += 1;
1230 ASSERT3U(db->db_dirtycnt, <=, 3);
1232 mutex_exit(&db->db_mtx);
1234 if (db->db_blkid == DMU_BONUS_BLKID ||
1235 db->db_blkid == DMU_SPILL_BLKID) {
1236 mutex_enter(&dn->dn_mtx);
1237 ASSERT(!list_link_active(&dr->dr_dirty_node));
1238 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1239 mutex_exit(&dn->dn_mtx);
1240 dnode_setdirty(dn, tx);
1243 } else if (do_free_accounting) {
1244 blkptr_t *bp = db->db_blkptr;
1245 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1246 bp_get_dsize(os->os_spa, bp) : db->db.db_size;
1248 * This is only a guess -- if the dbuf is dirty
1249 * in a previous txg, we don't know how much
1250 * space it will use on disk yet. We should
1251 * really have the struct_rwlock to access
1252 * db_blkptr, but since this is just a guess,
1253 * it's OK if we get an odd answer.
1255 ddt_prefetch(os->os_spa, bp);
1256 dnode_willuse_space(dn, -willfree, tx);
1259 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1260 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1261 drop_struct_lock = TRUE;
1264 if (db->db_level == 0) {
1265 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1266 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1269 if (db->db_level+1 < dn->dn_nlevels) {
1270 dmu_buf_impl_t *parent = db->db_parent;
1271 dbuf_dirty_record_t *di;
1272 int parent_held = FALSE;
1274 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1275 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1277 parent = dbuf_hold_level(dn, db->db_level+1,
1278 db->db_blkid >> epbs, FTAG);
1279 ASSERT(parent != NULL);
1282 if (drop_struct_lock)
1283 rw_exit(&dn->dn_struct_rwlock);
1284 ASSERT3U(db->db_level+1, ==, parent->db_level);
1285 di = dbuf_dirty(parent, tx);
1287 dbuf_rele(parent, FTAG);
1289 mutex_enter(&db->db_mtx);
1290 /* possible race with dbuf_undirty() */
1291 if (db->db_last_dirty == dr ||
1292 dn->dn_object == DMU_META_DNODE_OBJECT) {
1293 mutex_enter(&di->dt.di.dr_mtx);
1294 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1295 ASSERT(!list_link_active(&dr->dr_dirty_node));
1296 list_insert_tail(&di->dt.di.dr_children, dr);
1297 mutex_exit(&di->dt.di.dr_mtx);
1300 mutex_exit(&db->db_mtx);
1302 ASSERT(db->db_level+1 == dn->dn_nlevels);
1303 ASSERT(db->db_blkid < dn->dn_nblkptr);
1304 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf);
1305 mutex_enter(&dn->dn_mtx);
1306 ASSERT(!list_link_active(&dr->dr_dirty_node));
1307 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1308 mutex_exit(&dn->dn_mtx);
1309 if (drop_struct_lock)
1310 rw_exit(&dn->dn_struct_rwlock);
1313 dnode_setdirty(dn, tx);
1319 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1322 uint64_t txg = tx->tx_txg;
1323 dbuf_dirty_record_t *dr, **drp;
1326 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1328 mutex_enter(&db->db_mtx);
1330 * If this buffer is not dirty, we're done.
1332 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1333 if (dr->dr_txg <= txg)
1335 if (dr == NULL || dr->dr_txg < txg) {
1336 mutex_exit(&db->db_mtx);
1339 ASSERT(dr->dr_txg == txg);
1340 ASSERT(dr->dr_dbuf == db);
1346 * If this buffer is currently held, we cannot undirty
1347 * it, since one of the current holders may be in the
1348 * middle of an update. Note that users of dbuf_undirty()
1349 * should not place a hold on the dbuf before the call.
1351 if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
1352 mutex_exit(&db->db_mtx);
1353 /* Make sure we don't toss this buffer at sync phase */
1354 mutex_enter(&dn->dn_mtx);
1355 dnode_clear_range(dn, db->db_blkid, 1, tx);
1356 mutex_exit(&dn->dn_mtx);
1361 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1363 ASSERT(db->db.db_size != 0);
1365 /* XXX would be nice to fix up dn_towrite_space[] */
1369 if (dr->dr_parent) {
1370 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1371 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1372 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1373 } else if (db->db_level+1 == dn->dn_nlevels) {
1374 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
1375 mutex_enter(&dn->dn_mtx);
1376 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
1377 mutex_exit(&dn->dn_mtx);
1381 if (db->db_level == 0) {
1382 if (db->db_state != DB_NOFILL) {
1383 dbuf_unoverride(dr);
1385 ASSERT(db->db_buf != NULL);
1386 ASSERT(dr->dt.dl.dr_data != NULL);
1387 if (dr->dt.dl.dr_data != db->db_buf)
1388 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
1392 ASSERT(db->db_buf != NULL);
1393 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
1394 mutex_destroy(&dr->dt.di.dr_mtx);
1395 list_destroy(&dr->dt.di.dr_children);
1397 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1399 ASSERT(db->db_dirtycnt > 0);
1400 db->db_dirtycnt -= 1;
1402 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1403 arc_buf_t *buf = db->db_buf;
1405 ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
1406 dbuf_set_data(db, NULL);
1407 VERIFY(arc_buf_remove_ref(buf, db) == 1);
1412 mutex_exit(&db->db_mtx);
1416 #pragma weak dmu_buf_will_dirty = dbuf_will_dirty
1418 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1420 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1422 ASSERT(tx->tx_txg != 0);
1423 ASSERT(!refcount_is_zero(&db->db_holds));
1426 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
1427 rf |= DB_RF_HAVESTRUCT;
1429 (void) dbuf_read(db, NULL, rf);
1430 (void) dbuf_dirty(db, tx);
1434 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1436 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1438 db->db_state = DB_NOFILL;
1440 dmu_buf_will_fill(db_fake, tx);
1444 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1446 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1448 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1449 ASSERT(tx->tx_txg != 0);
1450 ASSERT(db->db_level == 0);
1451 ASSERT(!refcount_is_zero(&db->db_holds));
1453 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1454 dmu_tx_private_ok(tx));
1457 (void) dbuf_dirty(db, tx);
1460 #pragma weak dmu_buf_fill_done = dbuf_fill_done
1463 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1465 mutex_enter(&db->db_mtx);
1468 if (db->db_state == DB_FILL) {
1469 if (db->db_level == 0 && db->db_freed_in_flight) {
1470 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1471 /* we were freed while filling */
1472 /* XXX dbuf_undirty? */
1473 bzero(db->db.db_data, db->db.db_size);
1474 db->db_freed_in_flight = FALSE;
1476 db->db_state = DB_CACHED;
1477 cv_broadcast(&db->db_changed);
1479 mutex_exit(&db->db_mtx);
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.
1487 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
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);
1497 arc_return_buf(buf, db);
1498 ASSERT(arc_released(buf));
1500 mutex_enter(&db->db_mtx);
1502 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1503 cv_wait(&db->db_changed, &db->db_mtx);
1505 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
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) == 1);
1513 xuio_stat_wbuf_copied();
1517 xuio_stat_wbuf_nocopy();
1518 if (db->db_state == DB_CACHED) {
1519 dbuf_dirty_record_t *dr = db->db_last_dirty;
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 ==
1527 arc_release(db->db_buf, db);
1529 dr->dt.dl.dr_data = buf;
1530 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
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) == 1);
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 dbuf_fill_done(db, tx);
1546 * "Clear" the contents of this dbuf. This will mark the dbuf
1547 * EVICTING and clear *most* of its references. Unfortunetely,
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_buf_evict()->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_buf_evict()
1556 * ARC: dbuf_do_evict()->dbuf_destroy()
1559 dbuf_clear(dmu_buf_impl_t *db)
1562 dmu_buf_impl_t *parent = db->db_parent;
1563 dmu_buf_impl_t *dndb;
1564 int dbuf_gone = FALSE;
1566 ASSERT(MUTEX_HELD(&db->db_mtx));
1567 ASSERT(refcount_is_zero(&db->db_holds));
1569 dbuf_evict_user(db);
1571 if (db->db_state == DB_CACHED) {
1572 ASSERT(db->db.db_data != NULL);
1573 if (db->db_blkid == DMU_BONUS_BLKID) {
1574 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1575 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1577 db->db.db_data = NULL;
1578 db->db_state = DB_UNCACHED;
1581 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
1582 ASSERT(db->db_data_pending == NULL);
1584 db->db_state = DB_EVICTING;
1585 db->db_blkptr = NULL;
1590 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1591 list_remove(&dn->dn_dbufs, db);
1592 (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1596 * Decrementing the dbuf count means that the hold corresponding
1597 * to the removed dbuf is no longer discounted in dnode_move(),
1598 * so the dnode cannot be moved until after we release the hold.
1599 * The membar_producer() ensures visibility of the decremented
1600 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually
1604 db->db_dnode_handle = NULL;
1610 dbuf_gone = arc_buf_evict(db->db_buf);
1613 mutex_exit(&db->db_mtx);
1616 * If this dbuf is referenced from an indirect dbuf,
1617 * decrement the ref count on the indirect dbuf.
1619 if (parent && parent != dndb)
1620 dbuf_rele(parent, db);
1623 __attribute__((always_inline))
1625 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1626 dmu_buf_impl_t **parentp, blkptr_t **bpp, struct dbuf_hold_impl_data *dh)
1633 ASSERT(blkid != DMU_BONUS_BLKID);
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;
1642 dbuf_add_ref(dn->dn_dbuf, NULL);
1643 *parentp = dn->dn_dbuf;
1644 mutex_exit(&dn->dn_mtx);
1648 if (dn->dn_phys->dn_nlevels == 0)
1651 nlevels = dn->dn_phys->dn_nlevels;
1653 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
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 */
1661 } else if (level < nlevels-1) {
1662 /* this block is referenced from an indirect block */
1665 err = dbuf_hold_impl(dn, level+1, blkid >> epbs,
1666 fail_sparse, NULL, parentp);
1669 __dbuf_hold_impl_init(dh + 1, dn, dh->dh_level + 1,
1670 blkid >> epbs, fail_sparse, NULL,
1671 parentp, dh->dh_depth + 1);
1672 err = __dbuf_hold_impl(dh + 1);
1676 err = dbuf_read(*parentp, NULL,
1677 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1679 dbuf_rele(*parentp, NULL);
1683 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1684 (blkid & ((1ULL << epbs) - 1));
1687 /* the block is referenced from the dnode */
1688 ASSERT3U(level, ==, nlevels-1);
1689 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1690 blkid < dn->dn_phys->dn_nblkptr);
1692 dbuf_add_ref(dn->dn_dbuf, NULL);
1693 *parentp = dn->dn_dbuf;
1695 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1700 static dmu_buf_impl_t *
1701 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1702 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1704 objset_t *os = dn->dn_objset;
1705 dmu_buf_impl_t *db, *odb;
1707 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1708 ASSERT(dn->dn_type != DMU_OT_NONE);
1710 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP);
1713 db->db.db_object = dn->dn_object;
1714 db->db_level = level;
1715 db->db_blkid = blkid;
1716 db->db_last_dirty = NULL;
1717 db->db_dirtycnt = 0;
1718 db->db_dnode_handle = dn->dn_handle;
1719 db->db_parent = parent;
1720 db->db_blkptr = blkptr;
1722 db->db_user_ptr = NULL;
1723 db->db_user_data_ptr_ptr = NULL;
1724 db->db_evict_func = NULL;
1725 db->db_immediate_evict = 0;
1726 db->db_freed_in_flight = 0;
1728 if (blkid == DMU_BONUS_BLKID) {
1729 ASSERT3P(parent, ==, dn->dn_dbuf);
1730 db->db.db_size = DN_MAX_BONUSLEN -
1731 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1732 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1733 db->db.db_offset = DMU_BONUS_BLKID;
1734 db->db_state = DB_UNCACHED;
1735 /* the bonus dbuf is not placed in the hash table */
1736 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1738 } else if (blkid == DMU_SPILL_BLKID) {
1739 db->db.db_size = (blkptr != NULL) ?
1740 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE;
1741 db->db.db_offset = 0;
1744 db->db_level ? 1<<dn->dn_indblkshift : dn->dn_datablksz;
1745 db->db.db_size = blocksize;
1746 db->db.db_offset = db->db_blkid * blocksize;
1750 * Hold the dn_dbufs_mtx while we get the new dbuf
1751 * in the hash table *and* added to the dbufs list.
1752 * This prevents a possible deadlock with someone
1753 * trying to look up this dbuf before its added to the
1756 mutex_enter(&dn->dn_dbufs_mtx);
1757 db->db_state = DB_EVICTING;
1758 if ((odb = dbuf_hash_insert(db)) != NULL) {
1759 /* someone else inserted it first */
1760 kmem_cache_free(dbuf_cache, db);
1761 mutex_exit(&dn->dn_dbufs_mtx);
1764 list_insert_head(&dn->dn_dbufs, db);
1765 db->db_state = DB_UNCACHED;
1766 mutex_exit(&dn->dn_dbufs_mtx);
1767 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1769 if (parent && parent != dn->dn_dbuf)
1770 dbuf_add_ref(parent, db);
1772 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1773 refcount_count(&dn->dn_holds) > 0);
1774 (void) refcount_add(&dn->dn_holds, db);
1775 (void) atomic_inc_32_nv(&dn->dn_dbufs_count);
1777 dprintf_dbuf(db, "db=%p\n", db);
1783 dbuf_do_evict(void *private)
1785 arc_buf_t *buf = private;
1786 dmu_buf_impl_t *db = buf->b_private;
1788 if (!MUTEX_HELD(&db->db_mtx))
1789 mutex_enter(&db->db_mtx);
1791 ASSERT(refcount_is_zero(&db->db_holds));
1793 if (db->db_state != DB_EVICTING) {
1794 ASSERT(db->db_state == DB_CACHED);
1799 mutex_exit(&db->db_mtx);
1806 dbuf_destroy(dmu_buf_impl_t *db)
1808 ASSERT(refcount_is_zero(&db->db_holds));
1810 if (db->db_blkid != DMU_BONUS_BLKID) {
1812 * If this dbuf is still on the dn_dbufs list,
1813 * remove it from that list.
1815 if (db->db_dnode_handle != NULL) {
1820 mutex_enter(&dn->dn_dbufs_mtx);
1821 list_remove(&dn->dn_dbufs, db);
1822 (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1823 mutex_exit(&dn->dn_dbufs_mtx);
1826 * Decrementing the dbuf count means that the hold
1827 * corresponding to the removed dbuf is no longer
1828 * discounted in dnode_move(), so the dnode cannot be
1829 * moved until after we release the hold.
1832 db->db_dnode_handle = NULL;
1834 dbuf_hash_remove(db);
1836 db->db_parent = NULL;
1839 ASSERT(!list_link_active(&db->db_link));
1840 ASSERT(db->db.db_data == NULL);
1841 ASSERT(db->db_hash_next == NULL);
1842 ASSERT(db->db_blkptr == NULL);
1843 ASSERT(db->db_data_pending == NULL);
1845 kmem_cache_free(dbuf_cache, db);
1846 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1850 dbuf_prefetch(dnode_t *dn, uint64_t blkid)
1852 dmu_buf_impl_t *db = NULL;
1853 blkptr_t *bp = NULL;
1855 ASSERT(blkid != DMU_BONUS_BLKID);
1856 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1858 if (dnode_block_freed(dn, blkid))
1861 /* dbuf_find() returns with db_mtx held */
1862 if ((db = dbuf_find(dn, 0, blkid))) {
1864 * This dbuf is already in the cache. We assume that
1865 * it is already CACHED, or else about to be either
1868 mutex_exit(&db->db_mtx);
1872 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp, NULL) == 0) {
1873 if (bp && !BP_IS_HOLE(bp)) {
1874 int priority = dn->dn_type == DMU_OT_DDT_ZAP ?
1875 ZIO_PRIORITY_DDT_PREFETCH : ZIO_PRIORITY_ASYNC_READ;
1877 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
1878 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
1881 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1882 dn->dn_object, 0, blkid);
1887 pbuf = dn->dn_objset->os_phys_buf;
1889 (void) dsl_read(NULL, dn->dn_objset->os_spa,
1890 bp, pbuf, NULL, NULL, priority,
1891 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1895 dbuf_rele(db, NULL);
1899 #define DBUF_HOLD_IMPL_MAX_DEPTH 20
1902 * Returns with db_holds incremented, and db_mtx not held.
1903 * Note: dn_struct_rwlock must be held.
1906 __dbuf_hold_impl(struct dbuf_hold_impl_data *dh)
1908 ASSERT3S(dh->dh_depth, <, DBUF_HOLD_IMPL_MAX_DEPTH);
1909 dh->dh_parent = NULL;
1911 ASSERT(dh->dh_blkid != DMU_BONUS_BLKID);
1912 ASSERT(RW_LOCK_HELD(&dh->dh_dn->dn_struct_rwlock));
1913 ASSERT3U(dh->dh_dn->dn_nlevels, >, dh->dh_level);
1915 *(dh->dh_dbp) = NULL;
1917 /* dbuf_find() returns with db_mtx held */
1918 dh->dh_db = dbuf_find(dh->dh_dn, dh->dh_level, dh->dh_blkid);
1920 if (dh->dh_db == NULL) {
1923 ASSERT3P(dh->dh_parent, ==, NULL);
1924 dh->dh_err = dbuf_findbp(dh->dh_dn, dh->dh_level, dh->dh_blkid,
1925 dh->dh_fail_sparse, &dh->dh_parent,
1927 if (dh->dh_fail_sparse) {
1928 if (dh->dh_err == 0 && dh->dh_bp && BP_IS_HOLE(dh->dh_bp))
1929 dh->dh_err = ENOENT;
1932 dbuf_rele(dh->dh_parent, NULL);
1933 return (dh->dh_err);
1936 if (dh->dh_err && dh->dh_err != ENOENT)
1937 return (dh->dh_err);
1938 dh->dh_db = dbuf_create(dh->dh_dn, dh->dh_level, dh->dh_blkid,
1939 dh->dh_parent, dh->dh_bp);
1942 if (dh->dh_db->db_buf && refcount_is_zero(&dh->dh_db->db_holds)) {
1943 arc_buf_add_ref(dh->dh_db->db_buf, dh->dh_db);
1944 if (dh->dh_db->db_buf->b_data == NULL) {
1945 dbuf_clear(dh->dh_db);
1946 if (dh->dh_parent) {
1947 dbuf_rele(dh->dh_parent, NULL);
1948 dh->dh_parent = NULL;
1952 ASSERT3P(dh->dh_db->db.db_data, ==, dh->dh_db->db_buf->b_data);
1955 ASSERT(dh->dh_db->db_buf == NULL || arc_referenced(dh->dh_db->db_buf));
1958 * If this buffer is currently syncing out, and we are are
1959 * still referencing it from db_data, we need to make a copy
1960 * of it in case we decide we want to dirty it again in this txg.
1962 if (dh->dh_db->db_level == 0 &&
1963 dh->dh_db->db_blkid != DMU_BONUS_BLKID &&
1964 dh->dh_dn->dn_object != DMU_META_DNODE_OBJECT &&
1965 dh->dh_db->db_state == DB_CACHED && dh->dh_db->db_data_pending) {
1966 dh->dh_dr = dh->dh_db->db_data_pending;
1968 if (dh->dh_dr->dt.dl.dr_data == dh->dh_db->db_buf) {
1969 dh->dh_type = DBUF_GET_BUFC_TYPE(dh->dh_db);
1971 dbuf_set_data(dh->dh_db,
1972 arc_buf_alloc(dh->dh_dn->dn_objset->os_spa,
1973 dh->dh_db->db.db_size, dh->dh_db, dh->dh_type));
1974 bcopy(dh->dh_dr->dt.dl.dr_data->b_data,
1975 dh->dh_db->db.db_data, dh->dh_db->db.db_size);
1979 (void) refcount_add(&dh->dh_db->db_holds, dh->dh_tag);
1980 dbuf_update_data(dh->dh_db);
1981 DBUF_VERIFY(dh->dh_db);
1982 mutex_exit(&dh->dh_db->db_mtx);
1984 /* NOTE: we can't rele the parent until after we drop the db_mtx */
1986 dbuf_rele(dh->dh_parent, NULL);
1988 ASSERT3P(DB_DNODE(dh->dh_db), ==, dh->dh_dn);
1989 ASSERT3U(dh->dh_db->db_blkid, ==, dh->dh_blkid);
1990 ASSERT3U(dh->dh_db->db_level, ==, dh->dh_level);
1991 *(dh->dh_dbp) = dh->dh_db;
1997 * The following code preserves the recursive function dbuf_hold_impl()
1998 * but moves the local variables AND function arguments to the heap to
1999 * minimize the stack frame size. Enough space is initially allocated
2000 * on the stack for 20 levels of recursion.
2003 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
2004 void *tag, dmu_buf_impl_t **dbp)
2006 struct dbuf_hold_impl_data *dh;
2009 dh = kmem_zalloc(sizeof(struct dbuf_hold_impl_data) *
2010 DBUF_HOLD_IMPL_MAX_DEPTH, KM_SLEEP);
2011 __dbuf_hold_impl_init(dh, dn, level, blkid, fail_sparse, tag, dbp, 0);
2013 error = __dbuf_hold_impl(dh);
2015 kmem_free(dh, sizeof(struct dbuf_hold_impl_data) *
2016 DBUF_HOLD_IMPL_MAX_DEPTH);
2022 __dbuf_hold_impl_init(struct dbuf_hold_impl_data *dh,
2023 dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
2024 void *tag, dmu_buf_impl_t **dbp, int depth)
2027 dh->dh_level = level;
2028 dh->dh_blkid = blkid;
2029 dh->dh_fail_sparse = fail_sparse;
2032 dh->dh_depth = depth;
2036 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
2039 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
2040 return (err ? NULL : db);
2044 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
2047 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
2048 return (err ? NULL : db);
2052 dbuf_create_bonus(dnode_t *dn)
2054 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
2056 ASSERT(dn->dn_bonus == NULL);
2057 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL);
2061 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx)
2063 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2066 if (db->db_blkid != DMU_SPILL_BLKID)
2069 blksz = SPA_MINBLOCKSIZE;
2070 if (blksz > SPA_MAXBLOCKSIZE)
2071 blksz = SPA_MAXBLOCKSIZE;
2073 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE);
2077 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
2078 dbuf_new_size(db, blksz, tx);
2079 rw_exit(&dn->dn_struct_rwlock);
2086 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx)
2088 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx);
2091 #pragma weak dmu_buf_add_ref = dbuf_add_ref
2093 dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
2095 VERIFY(refcount_add(&db->db_holds, tag) > 1);
2099 * If you call dbuf_rele() you had better not be referencing the dnode handle
2100 * unless you have some other direct or indirect hold on the dnode. (An indirect
2101 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.)
2102 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the
2103 * dnode's parent dbuf evicting its dnode handles.
2105 #pragma weak dmu_buf_rele = dbuf_rele
2107 dbuf_rele(dmu_buf_impl_t *db, void *tag)
2109 mutex_enter(&db->db_mtx);
2110 dbuf_rele_and_unlock(db, tag);
2114 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
2115 * db_dirtycnt and db_holds to be updated atomically.
2118 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
2122 ASSERT(MUTEX_HELD(&db->db_mtx));
2126 * Remove the reference to the dbuf before removing its hold on the
2127 * dnode so we can guarantee in dnode_move() that a referenced bonus
2128 * buffer has a corresponding dnode hold.
2130 holds = refcount_remove(&db->db_holds, tag);
2134 * We can't freeze indirects if there is a possibility that they
2135 * may be modified in the current syncing context.
2137 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
2138 arc_buf_freeze(db->db_buf);
2140 if (holds == db->db_dirtycnt &&
2141 db->db_level == 0 && db->db_immediate_evict)
2142 dbuf_evict_user(db);
2145 if (db->db_blkid == DMU_BONUS_BLKID) {
2146 mutex_exit(&db->db_mtx);
2149 * If the dnode moves here, we cannot cross this barrier
2150 * until the move completes.
2153 (void) atomic_dec_32_nv(&DB_DNODE(db)->dn_dbufs_count);
2156 * The bonus buffer's dnode hold is no longer discounted
2157 * in dnode_move(). The dnode cannot move until after
2160 dnode_rele(DB_DNODE(db), db);
2161 } else if (db->db_buf == NULL) {
2163 * This is a special case: we never associated this
2164 * dbuf with any data allocated from the ARC.
2166 ASSERT(db->db_state == DB_UNCACHED ||
2167 db->db_state == DB_NOFILL);
2169 } else if (arc_released(db->db_buf)) {
2170 arc_buf_t *buf = db->db_buf;
2172 * This dbuf has anonymous data associated with it.
2174 dbuf_set_data(db, NULL);
2175 VERIFY(arc_buf_remove_ref(buf, db) == 1);
2178 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 0);
2179 if (!DBUF_IS_CACHEABLE(db))
2182 mutex_exit(&db->db_mtx);
2185 mutex_exit(&db->db_mtx);
2189 #pragma weak dmu_buf_refcount = dbuf_refcount
2191 dbuf_refcount(dmu_buf_impl_t *db)
2193 return (refcount_count(&db->db_holds));
2197 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
2198 dmu_buf_evict_func_t *evict_func)
2200 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
2201 user_data_ptr_ptr, evict_func));
2205 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
2206 dmu_buf_evict_func_t *evict_func)
2208 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2210 db->db_immediate_evict = TRUE;
2211 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
2212 user_data_ptr_ptr, evict_func));
2216 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr,
2217 void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func)
2219 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2220 ASSERT(db->db_level == 0);
2222 ASSERT((user_ptr == NULL) == (evict_func == NULL));
2224 mutex_enter(&db->db_mtx);
2226 if (db->db_user_ptr == old_user_ptr) {
2227 db->db_user_ptr = user_ptr;
2228 db->db_user_data_ptr_ptr = user_data_ptr_ptr;
2229 db->db_evict_func = evict_func;
2231 dbuf_update_data(db);
2233 old_user_ptr = db->db_user_ptr;
2236 mutex_exit(&db->db_mtx);
2237 return (old_user_ptr);
2241 dmu_buf_get_user(dmu_buf_t *db_fake)
2243 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2244 ASSERT(!refcount_is_zero(&db->db_holds));
2246 return (db->db_user_ptr);
2250 dmu_buf_freeable(dmu_buf_t *dbuf)
2252 boolean_t res = B_FALSE;
2253 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
2256 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
2257 db->db_blkptr, db->db_blkptr->blk_birth);
2263 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
2265 /* ASSERT(dmu_tx_is_syncing(tx) */
2266 ASSERT(MUTEX_HELD(&db->db_mtx));
2268 if (db->db_blkptr != NULL)
2271 if (db->db_blkid == DMU_SPILL_BLKID) {
2272 db->db_blkptr = &dn->dn_phys->dn_spill;
2273 BP_ZERO(db->db_blkptr);
2276 if (db->db_level == dn->dn_phys->dn_nlevels-1) {
2278 * This buffer was allocated at a time when there was
2279 * no available blkptrs from the dnode, or it was
2280 * inappropriate to hook it in (i.e., nlevels mis-match).
2282 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr);
2283 ASSERT(db->db_parent == NULL);
2284 db->db_parent = dn->dn_dbuf;
2285 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid];
2288 dmu_buf_impl_t *parent = db->db_parent;
2289 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2291 ASSERT(dn->dn_phys->dn_nlevels > 1);
2292 if (parent == NULL) {
2293 mutex_exit(&db->db_mtx);
2294 rw_enter(&dn->dn_struct_rwlock, RW_READER);
2295 (void) dbuf_hold_impl(dn, db->db_level+1,
2296 db->db_blkid >> epbs, FALSE, db, &parent);
2297 rw_exit(&dn->dn_struct_rwlock);
2298 mutex_enter(&db->db_mtx);
2299 db->db_parent = parent;
2301 db->db_blkptr = (blkptr_t *)parent->db.db_data +
2302 (db->db_blkid & ((1ULL << epbs) - 1));
2307 /* dbuf_sync_indirect() is called recursively from dbuf_sync_list() so it
2308 * is critical the we not allow the compiler to inline this function in to
2309 * dbuf_sync_list() thereby drastically bloating the stack usage.
2311 noinline static void
2312 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2314 dmu_buf_impl_t *db = dr->dr_dbuf;
2318 ASSERT(dmu_tx_is_syncing(tx));
2320 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2322 mutex_enter(&db->db_mtx);
2324 ASSERT(db->db_level > 0);
2327 if (db->db_buf == NULL) {
2328 mutex_exit(&db->db_mtx);
2329 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
2330 mutex_enter(&db->db_mtx);
2332 ASSERT3U(db->db_state, ==, DB_CACHED);
2333 ASSERT(db->db_buf != NULL);
2337 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2338 dbuf_check_blkptr(dn, db);
2341 db->db_data_pending = dr;
2343 mutex_exit(&db->db_mtx);
2344 dbuf_write(dr, db->db_buf, tx);
2347 mutex_enter(&dr->dt.di.dr_mtx);
2348 dbuf_sync_list(&dr->dt.di.dr_children, tx);
2349 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2350 mutex_exit(&dr->dt.di.dr_mtx);
2354 /* dbuf_sync_leaf() is called recursively from dbuf_sync_list() so it is
2355 * critical the we not allow the compiler to inline this function in to
2356 * dbuf_sync_list() thereby drastically bloating the stack usage.
2358 noinline static void
2359 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2361 arc_buf_t **datap = &dr->dt.dl.dr_data;
2362 dmu_buf_impl_t *db = dr->dr_dbuf;
2365 uint64_t txg = tx->tx_txg;
2367 ASSERT(dmu_tx_is_syncing(tx));
2369 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2371 mutex_enter(&db->db_mtx);
2373 * To be synced, we must be dirtied. But we
2374 * might have been freed after the dirty.
2376 if (db->db_state == DB_UNCACHED) {
2377 /* This buffer has been freed since it was dirtied */
2378 ASSERT(db->db.db_data == NULL);
2379 } else if (db->db_state == DB_FILL) {
2380 /* This buffer was freed and is now being re-filled */
2381 ASSERT(db->db.db_data != dr->dt.dl.dr_data);
2383 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL);
2390 if (db->db_blkid == DMU_SPILL_BLKID) {
2391 mutex_enter(&dn->dn_mtx);
2392 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR;
2393 mutex_exit(&dn->dn_mtx);
2397 * If this is a bonus buffer, simply copy the bonus data into the
2398 * dnode. It will be written out when the dnode is synced (and it
2399 * will be synced, since it must have been dirty for dbuf_sync to
2402 if (db->db_blkid == DMU_BONUS_BLKID) {
2403 dbuf_dirty_record_t **drp;
2405 ASSERT(*datap != NULL);
2406 ASSERT3U(db->db_level, ==, 0);
2407 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
2408 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
2411 if (*datap != db->db.db_data) {
2412 zio_buf_free(*datap, DN_MAX_BONUSLEN);
2413 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
2415 db->db_data_pending = NULL;
2416 drp = &db->db_last_dirty;
2418 drp = &(*drp)->dr_next;
2419 ASSERT(dr->dr_next == NULL);
2420 ASSERT(dr->dr_dbuf == db);
2422 if (dr->dr_dbuf->db_level != 0) {
2423 mutex_destroy(&dr->dt.di.dr_mtx);
2424 list_destroy(&dr->dt.di.dr_children);
2426 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2427 ASSERT(db->db_dirtycnt > 0);
2428 db->db_dirtycnt -= 1;
2429 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2436 * This function may have dropped the db_mtx lock allowing a dmu_sync
2437 * operation to sneak in. As a result, we need to ensure that we
2438 * don't check the dr_override_state until we have returned from
2439 * dbuf_check_blkptr.
2441 dbuf_check_blkptr(dn, db);
2444 * If this buffer is in the middle of an immediate write,
2445 * wait for the synchronous IO to complete.
2447 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
2448 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
2449 cv_wait(&db->db_changed, &db->db_mtx);
2450 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
2453 if (db->db_state != DB_NOFILL &&
2454 dn->dn_object != DMU_META_DNODE_OBJECT &&
2455 refcount_count(&db->db_holds) > 1 &&
2456 dr->dt.dl.dr_override_state != DR_OVERRIDDEN &&
2457 *datap == db->db_buf) {
2459 * If this buffer is currently "in use" (i.e., there
2460 * are active holds and db_data still references it),
2461 * then make a copy before we start the write so that
2462 * any modifications from the open txg will not leak
2465 * NOTE: this copy does not need to be made for
2466 * objects only modified in the syncing context (e.g.
2467 * DNONE_DNODE blocks).
2469 int blksz = arc_buf_size(*datap);
2470 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2471 *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
2472 bcopy(db->db.db_data, (*datap)->b_data, blksz);
2474 db->db_data_pending = dr;
2476 mutex_exit(&db->db_mtx);
2478 dbuf_write(dr, *datap, tx);
2480 ASSERT(!list_link_active(&dr->dr_dirty_node));
2481 if (dn->dn_object == DMU_META_DNODE_OBJECT) {
2482 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr);
2486 * Although zio_nowait() does not "wait for an IO", it does
2487 * initiate the IO. If this is an empty write it seems plausible
2488 * that the IO could actually be completed before the nowait
2489 * returns. We need to DB_DNODE_EXIT() first in case
2490 * zio_nowait() invalidates the dbuf.
2493 zio_nowait(dr->dr_zio);
2498 dbuf_sync_list(list_t *list, dmu_tx_t *tx)
2500 dbuf_dirty_record_t *dr;
2502 while ((dr = list_head(list))) {
2503 if (dr->dr_zio != NULL) {
2505 * If we find an already initialized zio then we
2506 * are processing the meta-dnode, and we have finished.
2507 * The dbufs for all dnodes are put back on the list
2508 * during processing, so that we can zio_wait()
2509 * these IOs after initiating all child IOs.
2511 ASSERT3U(dr->dr_dbuf->db.db_object, ==,
2512 DMU_META_DNODE_OBJECT);
2515 list_remove(list, dr);
2516 if (dr->dr_dbuf->db_level > 0)
2517 dbuf_sync_indirect(dr, tx);
2519 dbuf_sync_leaf(dr, tx);
2525 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
2527 dmu_buf_impl_t *db = vdb;
2529 blkptr_t *bp = zio->io_bp;
2530 blkptr_t *bp_orig = &zio->io_bp_orig;
2531 spa_t *spa = zio->io_spa;
2536 ASSERT(db->db_blkptr == bp);
2540 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig);
2541 dnode_diduse_space(dn, delta - zio->io_prev_space_delta);
2542 zio->io_prev_space_delta = delta;
2544 if (BP_IS_HOLE(bp)) {
2545 ASSERT(bp->blk_fill == 0);
2550 ASSERT((db->db_blkid != DMU_SPILL_BLKID &&
2551 BP_GET_TYPE(bp) == dn->dn_type) ||
2552 (db->db_blkid == DMU_SPILL_BLKID &&
2553 BP_GET_TYPE(bp) == dn->dn_bonustype));
2554 ASSERT(BP_GET_LEVEL(bp) == db->db_level);
2556 mutex_enter(&db->db_mtx);
2559 if (db->db_blkid == DMU_SPILL_BLKID) {
2560 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2561 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2562 db->db_blkptr == &dn->dn_phys->dn_spill);
2566 if (db->db_level == 0) {
2567 mutex_enter(&dn->dn_mtx);
2568 if (db->db_blkid > dn->dn_phys->dn_maxblkid &&
2569 db->db_blkid != DMU_SPILL_BLKID)
2570 dn->dn_phys->dn_maxblkid = db->db_blkid;
2571 mutex_exit(&dn->dn_mtx);
2573 if (dn->dn_type == DMU_OT_DNODE) {
2574 dnode_phys_t *dnp = db->db.db_data;
2575 for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
2577 if (dnp->dn_type != DMU_OT_NONE)
2584 blkptr_t *ibp = db->db.db_data;
2585 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2586 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
2587 if (BP_IS_HOLE(ibp))
2589 fill += ibp->blk_fill;
2594 bp->blk_fill = fill;
2596 mutex_exit(&db->db_mtx);
2601 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
2603 dmu_buf_impl_t *db = vdb;
2604 blkptr_t *bp = zio->io_bp;
2605 blkptr_t *bp_orig = &zio->io_bp_orig;
2606 uint64_t txg = zio->io_txg;
2607 dbuf_dirty_record_t **drp, *dr;
2609 ASSERT3U(zio->io_error, ==, 0);
2610 ASSERT(db->db_blkptr == bp);
2612 if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
2613 ASSERT(BP_EQUAL(bp, bp_orig));
2619 DB_GET_OBJSET(&os, db);
2620 ds = os->os_dsl_dataset;
2623 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
2624 dsl_dataset_block_born(ds, bp, tx);
2627 mutex_enter(&db->db_mtx);
2631 drp = &db->db_last_dirty;
2632 while ((dr = *drp) != db->db_data_pending)
2634 ASSERT(!list_link_active(&dr->dr_dirty_node));
2635 ASSERT(dr->dr_txg == txg);
2636 ASSERT(dr->dr_dbuf == db);
2637 ASSERT(dr->dr_next == NULL);
2641 if (db->db_blkid == DMU_SPILL_BLKID) {
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);
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,
2660 else if (!arc_released(db->db_buf))
2661 arc_set_callback(db->db_buf, dbuf_do_evict, 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 ASSERTV(int epbs = dn->dn_phys->dn_indblkshift -
2673 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
2675 ASSERT3U(dn->dn_phys->dn_maxblkid
2676 >> (db->db_level * epbs), >=, db->db_blkid);
2677 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2680 mutex_destroy(&dr->dt.di.dr_mtx);
2681 list_destroy(&dr->dt.di.dr_children);
2683 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2685 cv_broadcast(&db->db_changed);
2686 ASSERT(db->db_dirtycnt > 0);
2687 db->db_dirtycnt -= 1;
2688 db->db_data_pending = NULL;
2689 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2693 dbuf_write_nofill_ready(zio_t *zio)
2695 dbuf_write_ready(zio, NULL, zio->io_private);
2699 dbuf_write_nofill_done(zio_t *zio)
2701 dbuf_write_done(zio, NULL, zio->io_private);
2705 dbuf_write_override_ready(zio_t *zio)
2707 dbuf_dirty_record_t *dr = zio->io_private;
2708 dmu_buf_impl_t *db = dr->dr_dbuf;
2710 dbuf_write_ready(zio, NULL, db);
2714 dbuf_write_override_done(zio_t *zio)
2716 dbuf_dirty_record_t *dr = zio->io_private;
2717 dmu_buf_impl_t *db = dr->dr_dbuf;
2718 blkptr_t *obp = &dr->dt.dl.dr_overridden_by;
2720 mutex_enter(&db->db_mtx);
2721 if (!BP_EQUAL(zio->io_bp, obp)) {
2722 if (!BP_IS_HOLE(obp))
2723 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp);
2724 arc_release(dr->dt.dl.dr_data, db);
2726 mutex_exit(&db->db_mtx);
2728 dbuf_write_done(zio, NULL, db);
2732 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
2734 dmu_buf_impl_t *db = dr->dr_dbuf;
2737 dmu_buf_impl_t *parent = db->db_parent;
2738 uint64_t txg = tx->tx_txg;
2748 if (db->db_state != DB_NOFILL) {
2749 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) {
2751 * Private object buffers are released here rather
2752 * than in dbuf_dirty() since they are only modified
2753 * in the syncing context and we don't want the
2754 * overhead of making multiple copies of the data.
2756 if (BP_IS_HOLE(db->db_blkptr)) {
2759 dbuf_release_bp(db);
2764 if (parent != dn->dn_dbuf) {
2765 ASSERT(parent && parent->db_data_pending);
2766 ASSERT(db->db_level == parent->db_level-1);
2767 ASSERT(arc_released(parent->db_buf));
2768 zio = parent->db_data_pending->dr_zio;
2770 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 &&
2771 db->db_blkid != DMU_SPILL_BLKID) ||
2772 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0));
2773 if (db->db_blkid != DMU_SPILL_BLKID)
2774 ASSERT3P(db->db_blkptr, ==,
2775 &dn->dn_phys->dn_blkptr[db->db_blkid]);
2779 ASSERT(db->db_level == 0 || data == db->db_buf);
2780 ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
2783 SET_BOOKMARK(&zb, os->os_dsl_dataset ?
2784 os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
2785 db->db.db_object, db->db_level, db->db_blkid);
2787 if (db->db_blkid == DMU_SPILL_BLKID)
2789 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0;
2791 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp);
2794 if (db->db_level == 0 && dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
2795 ASSERT(db->db_state != DB_NOFILL);
2796 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2797 db->db_blkptr, data->b_data, arc_buf_size(data), &zp,
2798 dbuf_write_override_ready, dbuf_write_override_done, dr,
2799 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2800 mutex_enter(&db->db_mtx);
2801 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
2802 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by,
2803 dr->dt.dl.dr_copies);
2804 mutex_exit(&db->db_mtx);
2805 } else if (db->db_state == DB_NOFILL) {
2806 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF);
2807 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2808 db->db_blkptr, NULL, db->db.db_size, &zp,
2809 dbuf_write_nofill_ready, dbuf_write_nofill_done, db,
2810 ZIO_PRIORITY_ASYNC_WRITE,
2811 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb);
2813 ASSERT(arc_released(data));
2814 dr->dr_zio = arc_write(zio, os->os_spa, txg,
2815 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), &zp,
2816 dbuf_write_ready, dbuf_write_done, db,
2817 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2821 #if defined(_KERNEL) && defined(HAVE_SPL)
2822 EXPORT_SYMBOL(dmu_buf_rele);
2823 EXPORT_SYMBOL(dmu_buf_will_dirty);