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.
23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 * Copyright (c) 2012 by Delphix. All rights reserved.
25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
28 #include <sys/zfs_context.h>
31 #include <sys/dmu_impl.h>
33 #include <sys/dmu_objset.h>
34 #include <sys/dsl_dataset.h>
35 #include <sys/dsl_dir.h>
36 #include <sys/dmu_tx.h>
39 #include <sys/dmu_zfetch.h>
41 #include <sys/sa_impl.h>
43 struct dbuf_hold_impl_data {
44 /* Function arguments */
50 dmu_buf_impl_t **dh_dbp;
52 dmu_buf_impl_t *dh_db;
53 dmu_buf_impl_t *dh_parent;
56 dbuf_dirty_record_t *dh_dr;
57 arc_buf_contents_t dh_type;
61 static void __dbuf_hold_impl_init(struct dbuf_hold_impl_data *dh,
62 dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
63 void *tag, dmu_buf_impl_t **dbp, int depth);
64 static int __dbuf_hold_impl(struct dbuf_hold_impl_data *dh);
66 static void dbuf_destroy(dmu_buf_impl_t *db);
67 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
68 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
71 * Global data structures and functions for the dbuf cache.
73 static kmem_cache_t *dbuf_cache;
77 dbuf_cons(void *vdb, void *unused, int kmflag)
79 dmu_buf_impl_t *db = vdb;
80 bzero(db, sizeof (dmu_buf_impl_t));
82 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
83 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
84 refcount_create(&db->db_holds);
85 list_link_init(&db->db_link);
91 dbuf_dest(void *vdb, void *unused)
93 dmu_buf_impl_t *db = vdb;
94 mutex_destroy(&db->db_mtx);
95 cv_destroy(&db->db_changed);
96 refcount_destroy(&db->db_holds);
100 * dbuf hash table routines
102 static dbuf_hash_table_t dbuf_hash_table;
104 static uint64_t dbuf_hash_count;
107 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
109 uintptr_t osv = (uintptr_t)os;
110 uint64_t crc = -1ULL;
112 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
113 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
114 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
115 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
116 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
117 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
118 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
120 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
125 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
127 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
128 ((dbuf)->db.db_object == (obj) && \
129 (dbuf)->db_objset == (os) && \
130 (dbuf)->db_level == (level) && \
131 (dbuf)->db_blkid == (blkid))
134 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
136 dbuf_hash_table_t *h = &dbuf_hash_table;
137 objset_t *os = dn->dn_objset;
144 hv = DBUF_HASH(os, obj, level, blkid);
145 idx = hv & h->hash_table_mask;
147 mutex_enter(DBUF_HASH_MUTEX(h, idx));
148 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
149 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
150 mutex_enter(&db->db_mtx);
151 if (db->db_state != DB_EVICTING) {
152 mutex_exit(DBUF_HASH_MUTEX(h, idx));
155 mutex_exit(&db->db_mtx);
158 mutex_exit(DBUF_HASH_MUTEX(h, idx));
163 * Insert an entry into the hash table. If there is already an element
164 * equal to elem in the hash table, then the already existing element
165 * will be returned and the new element will not be inserted.
166 * Otherwise returns NULL.
168 static dmu_buf_impl_t *
169 dbuf_hash_insert(dmu_buf_impl_t *db)
171 dbuf_hash_table_t *h = &dbuf_hash_table;
172 objset_t *os = db->db_objset;
173 uint64_t obj = db->db.db_object;
174 int level = db->db_level;
175 uint64_t blkid, hv, idx;
178 blkid = db->db_blkid;
179 hv = DBUF_HASH(os, obj, level, blkid);
180 idx = hv & h->hash_table_mask;
182 mutex_enter(DBUF_HASH_MUTEX(h, idx));
183 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
184 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
185 mutex_enter(&dbf->db_mtx);
186 if (dbf->db_state != DB_EVICTING) {
187 mutex_exit(DBUF_HASH_MUTEX(h, idx));
190 mutex_exit(&dbf->db_mtx);
194 mutex_enter(&db->db_mtx);
195 db->db_hash_next = h->hash_table[idx];
196 h->hash_table[idx] = db;
197 mutex_exit(DBUF_HASH_MUTEX(h, idx));
198 atomic_add_64(&dbuf_hash_count, 1);
204 * Remove an entry from the hash table. This operation will
205 * fail if there are any existing holds on the db.
208 dbuf_hash_remove(dmu_buf_impl_t *db)
210 dbuf_hash_table_t *h = &dbuf_hash_table;
212 dmu_buf_impl_t *dbf, **dbp;
214 hv = DBUF_HASH(db->db_objset, db->db.db_object,
215 db->db_level, db->db_blkid);
216 idx = hv & h->hash_table_mask;
219 * We musn't hold db_mtx to maintin lock ordering:
220 * DBUF_HASH_MUTEX > db_mtx.
222 ASSERT(refcount_is_zero(&db->db_holds));
223 ASSERT(db->db_state == DB_EVICTING);
224 ASSERT(!MUTEX_HELD(&db->db_mtx));
226 mutex_enter(DBUF_HASH_MUTEX(h, idx));
227 dbp = &h->hash_table[idx];
228 while ((dbf = *dbp) != db) {
229 dbp = &dbf->db_hash_next;
232 *dbp = db->db_hash_next;
233 db->db_hash_next = NULL;
234 mutex_exit(DBUF_HASH_MUTEX(h, idx));
235 atomic_add_64(&dbuf_hash_count, -1);
238 static arc_evict_func_t dbuf_do_evict;
241 dbuf_evict_user(dmu_buf_impl_t *db)
243 ASSERT(MUTEX_HELD(&db->db_mtx));
245 if (db->db_level != 0 || db->db_evict_func == NULL)
248 if (db->db_user_data_ptr_ptr)
249 *db->db_user_data_ptr_ptr = db->db.db_data;
250 db->db_evict_func(&db->db, db->db_user_ptr);
251 db->db_user_ptr = NULL;
252 db->db_user_data_ptr_ptr = NULL;
253 db->db_evict_func = NULL;
257 dbuf_is_metadata(dmu_buf_impl_t *db)
259 if (db->db_level > 0) {
262 boolean_t is_metadata;
265 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type);
268 return (is_metadata);
273 dbuf_evict(dmu_buf_impl_t *db)
275 ASSERT(MUTEX_HELD(&db->db_mtx));
276 ASSERT(db->db_buf == NULL);
277 ASSERT(db->db_data_pending == NULL);
286 uint64_t hsize = 1ULL << 16;
287 dbuf_hash_table_t *h = &dbuf_hash_table;
291 * The hash table is big enough to fill all of physical memory
292 * with an average 4K block size. The table will take up
293 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
295 while (hsize * 4096 < physmem * PAGESIZE)
299 h->hash_table_mask = hsize - 1;
300 #if defined(_KERNEL) && defined(HAVE_SPL)
301 /* Large allocations which do not require contiguous pages
302 * should be using vmem_alloc() in the linux kernel */
303 h->hash_table = vmem_zalloc(hsize * sizeof (void *), KM_PUSHPAGE);
305 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
307 if (h->hash_table == NULL) {
308 /* XXX - we should really return an error instead of assert */
309 ASSERT(hsize > (1ULL << 10));
314 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
315 sizeof (dmu_buf_impl_t),
316 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
318 for (i = 0; i < DBUF_MUTEXES; i++)
319 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
327 dbuf_hash_table_t *h = &dbuf_hash_table;
330 dbuf_stats_destroy();
332 for (i = 0; i < DBUF_MUTEXES; i++)
333 mutex_destroy(&h->hash_mutexes[i]);
334 #if defined(_KERNEL) && defined(HAVE_SPL)
335 /* Large allocations which do not require contiguous pages
336 * should be using vmem_free() in the linux kernel */
337 vmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
339 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
341 kmem_cache_destroy(dbuf_cache);
350 dbuf_verify(dmu_buf_impl_t *db)
353 dbuf_dirty_record_t *dr;
355 ASSERT(MUTEX_HELD(&db->db_mtx));
357 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
360 ASSERT(db->db_objset != NULL);
364 ASSERT(db->db_parent == NULL);
365 ASSERT(db->db_blkptr == NULL);
367 ASSERT3U(db->db.db_object, ==, dn->dn_object);
368 ASSERT3P(db->db_objset, ==, dn->dn_objset);
369 ASSERT3U(db->db_level, <, dn->dn_nlevels);
370 ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
371 db->db_blkid == DMU_SPILL_BLKID ||
372 !list_is_empty(&dn->dn_dbufs));
374 if (db->db_blkid == DMU_BONUS_BLKID) {
376 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
377 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID);
378 } else if (db->db_blkid == DMU_SPILL_BLKID) {
380 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
381 ASSERT0(db->db.db_offset);
383 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
386 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
387 ASSERT(dr->dr_dbuf == db);
389 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
390 ASSERT(dr->dr_dbuf == db);
393 * We can't assert that db_size matches dn_datablksz because it
394 * can be momentarily different when another thread is doing
397 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
398 dr = db->db_data_pending;
400 * It should only be modified in syncing context, so
401 * make sure we only have one copy of the data.
403 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
406 /* verify db->db_blkptr */
408 if (db->db_parent == dn->dn_dbuf) {
409 /* db is pointed to by the dnode */
410 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
411 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
412 ASSERT(db->db_parent == NULL);
414 ASSERT(db->db_parent != NULL);
415 if (db->db_blkid != DMU_SPILL_BLKID)
416 ASSERT3P(db->db_blkptr, ==,
417 &dn->dn_phys->dn_blkptr[db->db_blkid]);
419 /* db is pointed to by an indirect block */
420 ASSERTV(int epb = db->db_parent->db.db_size >>
422 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
423 ASSERT3U(db->db_parent->db.db_object, ==,
426 * dnode_grow_indblksz() can make this fail if we don't
427 * have the struct_rwlock. XXX indblksz no longer
428 * grows. safe to do this now?
430 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
431 ASSERT3P(db->db_blkptr, ==,
432 ((blkptr_t *)db->db_parent->db.db_data +
433 db->db_blkid % epb));
437 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
438 (db->db_buf == NULL || db->db_buf->b_data) &&
439 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID &&
440 db->db_state != DB_FILL && !dn->dn_free_txg) {
442 * If the blkptr isn't set but they have nonzero data,
443 * it had better be dirty, otherwise we'll lose that
444 * data when we evict this buffer.
446 if (db->db_dirtycnt == 0) {
447 ASSERTV(uint64_t *buf = db->db.db_data);
450 for (i = 0; i < db->db.db_size >> 3; i++) {
460 dbuf_update_data(dmu_buf_impl_t *db)
462 ASSERT(MUTEX_HELD(&db->db_mtx));
463 if (db->db_level == 0 && db->db_user_data_ptr_ptr) {
464 ASSERT(!refcount_is_zero(&db->db_holds));
465 *db->db_user_data_ptr_ptr = db->db.db_data;
470 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
472 ASSERT(MUTEX_HELD(&db->db_mtx));
473 ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf));
476 ASSERT(buf->b_data != NULL);
477 db->db.db_data = buf->b_data;
478 if (!arc_released(buf))
479 arc_set_callback(buf, dbuf_do_evict, db);
480 dbuf_update_data(db);
483 db->db.db_data = NULL;
484 if (db->db_state != DB_NOFILL)
485 db->db_state = DB_UNCACHED;
490 * Loan out an arc_buf for read. Return the loaned arc_buf.
493 dbuf_loan_arcbuf(dmu_buf_impl_t *db)
497 mutex_enter(&db->db_mtx);
498 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
499 int blksz = db->db.db_size;
502 mutex_exit(&db->db_mtx);
503 DB_GET_SPA(&spa, db);
504 abuf = arc_loan_buf(spa, blksz);
505 bcopy(db->db.db_data, abuf->b_data, blksz);
508 arc_loan_inuse_buf(abuf, db);
509 dbuf_set_data(db, NULL);
510 mutex_exit(&db->db_mtx);
516 dbuf_whichblock(dnode_t *dn, uint64_t offset)
518 if (dn->dn_datablkshift) {
519 return (offset >> dn->dn_datablkshift);
521 ASSERT3U(offset, <, dn->dn_datablksz);
527 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
529 dmu_buf_impl_t *db = vdb;
531 mutex_enter(&db->db_mtx);
532 ASSERT3U(db->db_state, ==, DB_READ);
534 * All reads are synchronous, so we must have a hold on the dbuf
536 ASSERT(refcount_count(&db->db_holds) > 0);
537 ASSERT(db->db_buf == NULL);
538 ASSERT(db->db.db_data == NULL);
539 if (db->db_level == 0 && db->db_freed_in_flight) {
540 /* we were freed in flight; disregard any error */
541 arc_release(buf, db);
542 bzero(buf->b_data, db->db.db_size);
544 db->db_freed_in_flight = FALSE;
545 dbuf_set_data(db, buf);
546 db->db_state = DB_CACHED;
547 } else if (zio == NULL || zio->io_error == 0) {
548 dbuf_set_data(db, buf);
549 db->db_state = DB_CACHED;
551 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
552 ASSERT3P(db->db_buf, ==, NULL);
553 VERIFY(arc_buf_remove_ref(buf, db));
554 db->db_state = DB_UNCACHED;
556 cv_broadcast(&db->db_changed);
557 dbuf_rele_and_unlock(db, NULL);
561 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
566 uint32_t aflags = ARC_NOWAIT;
570 ASSERT(!refcount_is_zero(&db->db_holds));
571 /* We need the struct_rwlock to prevent db_blkptr from changing. */
572 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
573 ASSERT(MUTEX_HELD(&db->db_mtx));
574 ASSERT(db->db_state == DB_UNCACHED);
575 ASSERT(db->db_buf == NULL);
577 if (db->db_blkid == DMU_BONUS_BLKID) {
578 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
580 ASSERT3U(bonuslen, <=, db->db.db_size);
581 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
582 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
583 if (bonuslen < DN_MAX_BONUSLEN)
584 bzero(db->db.db_data, DN_MAX_BONUSLEN);
586 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
588 dbuf_update_data(db);
589 db->db_state = DB_CACHED;
590 mutex_exit(&db->db_mtx);
595 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
596 * processes the delete record and clears the bp while we are waiting
597 * for the dn_mtx (resulting in a "no" from block_freed).
599 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
600 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
601 BP_IS_HOLE(db->db_blkptr)))) {
602 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
604 dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa,
605 db->db.db_size, db, type));
607 bzero(db->db.db_data, db->db.db_size);
608 db->db_state = DB_CACHED;
609 *flags |= DB_RF_CACHED;
610 mutex_exit(&db->db_mtx);
614 spa = dn->dn_objset->os_spa;
617 db->db_state = DB_READ;
618 mutex_exit(&db->db_mtx);
620 if (DBUF_IS_L2CACHEABLE(db))
621 aflags |= ARC_L2CACHE;
622 if (DBUF_IS_L2COMPRESSIBLE(db))
623 aflags |= ARC_L2COMPRESS;
625 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
626 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
627 db->db.db_object, db->db_level, db->db_blkid);
629 dbuf_add_ref(db, NULL);
631 (void) arc_read(zio, spa, db->db_blkptr,
632 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
633 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
635 if (aflags & ARC_CACHED)
636 *flags |= DB_RF_CACHED;
640 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
643 int havepzio = (zio != NULL);
648 * We don't have to hold the mutex to check db_state because it
649 * can't be freed while we have a hold on the buffer.
651 ASSERT(!refcount_is_zero(&db->db_holds));
653 if (db->db_state == DB_NOFILL)
658 if ((flags & DB_RF_HAVESTRUCT) == 0)
659 rw_enter(&dn->dn_struct_rwlock, RW_READER);
661 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
662 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL &&
663 DBUF_IS_CACHEABLE(db);
665 mutex_enter(&db->db_mtx);
666 if (db->db_state == DB_CACHED) {
667 mutex_exit(&db->db_mtx);
669 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
670 db->db.db_size, TRUE);
671 if ((flags & DB_RF_HAVESTRUCT) == 0)
672 rw_exit(&dn->dn_struct_rwlock);
674 } else if (db->db_state == DB_UNCACHED) {
675 spa_t *spa = dn->dn_objset->os_spa;
678 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
679 dbuf_read_impl(db, zio, &flags);
681 /* dbuf_read_impl has dropped db_mtx for us */
684 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
685 db->db.db_size, flags & DB_RF_CACHED);
687 if ((flags & DB_RF_HAVESTRUCT) == 0)
688 rw_exit(&dn->dn_struct_rwlock);
694 mutex_exit(&db->db_mtx);
696 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
697 db->db.db_size, TRUE);
698 if ((flags & DB_RF_HAVESTRUCT) == 0)
699 rw_exit(&dn->dn_struct_rwlock);
702 mutex_enter(&db->db_mtx);
703 if ((flags & DB_RF_NEVERWAIT) == 0) {
704 while (db->db_state == DB_READ ||
705 db->db_state == DB_FILL) {
706 ASSERT(db->db_state == DB_READ ||
707 (flags & DB_RF_HAVESTRUCT) == 0);
708 cv_wait(&db->db_changed, &db->db_mtx);
710 if (db->db_state == DB_UNCACHED)
713 mutex_exit(&db->db_mtx);
716 ASSERT(err || havepzio || db->db_state == DB_CACHED);
721 dbuf_noread(dmu_buf_impl_t *db)
723 ASSERT(!refcount_is_zero(&db->db_holds));
724 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
725 mutex_enter(&db->db_mtx);
726 while (db->db_state == DB_READ || db->db_state == DB_FILL)
727 cv_wait(&db->db_changed, &db->db_mtx);
728 if (db->db_state == DB_UNCACHED) {
729 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
732 ASSERT(db->db_buf == NULL);
733 ASSERT(db->db.db_data == NULL);
734 DB_GET_SPA(&spa, db);
735 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type));
736 db->db_state = DB_FILL;
737 } else if (db->db_state == DB_NOFILL) {
738 dbuf_set_data(db, NULL);
740 ASSERT3U(db->db_state, ==, DB_CACHED);
742 mutex_exit(&db->db_mtx);
746 * This is our just-in-time copy function. It makes a copy of
747 * buffers, that have been modified in a previous transaction
748 * group, before we modify them in the current active group.
750 * This function is used in two places: when we are dirtying a
751 * buffer for the first time in a txg, and when we are freeing
752 * a range in a dnode that includes this buffer.
754 * Note that when we are called from dbuf_free_range() we do
755 * not put a hold on the buffer, we just traverse the active
756 * dbuf list for the dnode.
759 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
761 dbuf_dirty_record_t *dr = db->db_last_dirty;
763 ASSERT(MUTEX_HELD(&db->db_mtx));
764 ASSERT(db->db.db_data != NULL);
765 ASSERT(db->db_level == 0);
766 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT);
769 (dr->dt.dl.dr_data !=
770 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf)))
774 * If the last dirty record for this dbuf has not yet synced
775 * and its referencing the dbuf data, either:
776 * reset the reference to point to a new copy,
777 * or (if there a no active holders)
778 * just null out the current db_data pointer.
780 ASSERT(dr->dr_txg >= txg - 2);
781 if (db->db_blkid == DMU_BONUS_BLKID) {
782 /* Note that the data bufs here are zio_bufs */
783 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
784 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
785 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
786 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
787 int size = db->db.db_size;
788 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
791 DB_GET_SPA(&spa, db);
792 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type);
793 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
795 dbuf_set_data(db, NULL);
800 dbuf_unoverride(dbuf_dirty_record_t *dr)
802 dmu_buf_impl_t *db = dr->dr_dbuf;
803 blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
804 uint64_t txg = dr->dr_txg;
806 ASSERT(MUTEX_HELD(&db->db_mtx));
807 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
808 ASSERT(db->db_level == 0);
810 if (db->db_blkid == DMU_BONUS_BLKID ||
811 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
814 ASSERT(db->db_data_pending != dr);
816 /* free this block */
817 if (!BP_IS_HOLE(bp)) {
820 DB_GET_SPA(&spa, db);
821 zio_free(spa, txg, bp);
823 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
825 * Release the already-written buffer, so we leave it in
826 * a consistent dirty state. Note that all callers are
827 * modifying the buffer, so they will immediately do
828 * another (redundant) arc_release(). Therefore, leave
829 * the buf thawed to save the effort of freezing &
830 * immediately re-thawing it.
832 arc_release(dr->dt.dl.dr_data, db);
836 * Evict (if its unreferenced) or clear (if its referenced) any level-0
837 * data blocks in the free range, so that any future readers will find
838 * empty blocks. Also, if we happen accross any level-1 dbufs in the
839 * range that have not already been marked dirty, mark them dirty so
840 * they stay in memory.
843 dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
845 dmu_buf_impl_t *db, *db_next;
846 uint64_t txg = tx->tx_txg;
847 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
848 uint64_t first_l1 = start >> epbs;
849 uint64_t last_l1 = end >> epbs;
851 if (end > dn->dn_maxblkid && (end != DMU_SPILL_BLKID)) {
852 end = dn->dn_maxblkid;
853 last_l1 = end >> epbs;
855 dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
856 mutex_enter(&dn->dn_dbufs_mtx);
857 for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
858 db_next = list_next(&dn->dn_dbufs, db);
859 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
861 if (db->db_level == 1 &&
862 db->db_blkid >= first_l1 && db->db_blkid <= last_l1) {
863 mutex_enter(&db->db_mtx);
864 if (db->db_last_dirty &&
865 db->db_last_dirty->dr_txg < txg) {
866 dbuf_add_ref(db, FTAG);
867 mutex_exit(&db->db_mtx);
868 dbuf_will_dirty(db, tx);
871 mutex_exit(&db->db_mtx);
875 if (db->db_level != 0)
877 dprintf_dbuf(db, "found buf %s\n", "");
878 if (db->db_blkid < start || db->db_blkid > end)
881 /* found a level 0 buffer in the range */
882 mutex_enter(&db->db_mtx);
883 if (dbuf_undirty(db, tx)) {
884 /* mutex has been dropped and dbuf destroyed */
888 if (db->db_state == DB_UNCACHED ||
889 db->db_state == DB_NOFILL ||
890 db->db_state == DB_EVICTING) {
891 ASSERT(db->db.db_data == NULL);
892 mutex_exit(&db->db_mtx);
895 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
896 /* will be handled in dbuf_read_done or dbuf_rele */
897 db->db_freed_in_flight = TRUE;
898 mutex_exit(&db->db_mtx);
901 if (refcount_count(&db->db_holds) == 0) {
906 /* The dbuf is referenced */
908 if (db->db_last_dirty != NULL) {
909 dbuf_dirty_record_t *dr = db->db_last_dirty;
911 if (dr->dr_txg == txg) {
913 * This buffer is "in-use", re-adjust the file
914 * size to reflect that this buffer may
915 * contain new data when we sync.
917 if (db->db_blkid != DMU_SPILL_BLKID &&
918 db->db_blkid > dn->dn_maxblkid)
919 dn->dn_maxblkid = db->db_blkid;
923 * This dbuf is not dirty in the open context.
924 * Either uncache it (if its not referenced in
925 * the open context) or reset its contents to
928 dbuf_fix_old_data(db, txg);
931 /* clear the contents if its cached */
932 if (db->db_state == DB_CACHED) {
933 ASSERT(db->db.db_data != NULL);
934 arc_release(db->db_buf, db);
935 bzero(db->db.db_data, db->db.db_size);
936 arc_buf_freeze(db->db_buf);
939 mutex_exit(&db->db_mtx);
941 mutex_exit(&dn->dn_dbufs_mtx);
945 dbuf_block_freeable(dmu_buf_impl_t *db)
947 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
948 uint64_t birth_txg = 0;
951 * We don't need any locking to protect db_blkptr:
952 * If it's syncing, then db_last_dirty will be set
953 * so we'll ignore db_blkptr.
955 ASSERT(MUTEX_HELD(&db->db_mtx));
956 if (db->db_last_dirty)
957 birth_txg = db->db_last_dirty->dr_txg;
958 else if (db->db_blkptr)
959 birth_txg = db->db_blkptr->blk_birth;
962 * If we don't exist or are in a snapshot, we can't be freed.
963 * Don't pass the bp to dsl_dataset_block_freeable() since we
964 * are holding the db_mtx lock and might deadlock if we are
965 * prefetching a dedup-ed block.
968 return (ds == NULL ||
969 dsl_dataset_block_freeable(ds, NULL, birth_txg));
975 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
977 arc_buf_t *buf, *obuf;
978 int osize = db->db.db_size;
979 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
982 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
987 /* XXX does *this* func really need the lock? */
988 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
991 * This call to dbuf_will_dirty() with the dn_struct_rwlock held
992 * is OK, because there can be no other references to the db
993 * when we are changing its size, so no concurrent DB_FILL can
997 * XXX we should be doing a dbuf_read, checking the return
998 * value and returning that up to our callers
1000 dbuf_will_dirty(db, tx);
1002 /* create the data buffer for the new block */
1003 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type);
1005 /* copy old block data to the new block */
1007 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
1008 /* zero the remainder */
1010 bzero((uint8_t *)buf->b_data + osize, size - osize);
1012 mutex_enter(&db->db_mtx);
1013 dbuf_set_data(db, buf);
1014 VERIFY(arc_buf_remove_ref(obuf, db));
1015 db->db.db_size = size;
1017 if (db->db_level == 0) {
1018 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
1019 db->db_last_dirty->dt.dl.dr_data = buf;
1021 mutex_exit(&db->db_mtx);
1023 dnode_willuse_space(dn, size-osize, tx);
1028 dbuf_release_bp(dmu_buf_impl_t *db)
1032 DB_GET_OBJSET(&os, db);
1033 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
1034 ASSERT(arc_released(os->os_phys_buf) ||
1035 list_link_active(&os->os_dsl_dataset->ds_synced_link));
1036 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf));
1038 (void) arc_release(db->db_buf, db);
1041 dbuf_dirty_record_t *
1042 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1046 dbuf_dirty_record_t **drp, *dr;
1047 int drop_struct_lock = FALSE;
1048 boolean_t do_free_accounting = B_FALSE;
1049 int txgoff = tx->tx_txg & TXG_MASK;
1051 ASSERT(tx->tx_txg != 0);
1052 ASSERT(!refcount_is_zero(&db->db_holds));
1053 DMU_TX_DIRTY_BUF(tx, db);
1058 * Shouldn't dirty a regular buffer in syncing context. Private
1059 * objects may be dirtied in syncing context, but only if they
1060 * were already pre-dirtied in open context.
1062 ASSERT(!dmu_tx_is_syncing(tx) ||
1063 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
1064 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1065 dn->dn_objset->os_dsl_dataset == NULL);
1067 * We make this assert for private objects as well, but after we
1068 * check if we're already dirty. They are allowed to re-dirty
1069 * in syncing context.
1071 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1072 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1073 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1075 mutex_enter(&db->db_mtx);
1077 * XXX make this true for indirects too? The problem is that
1078 * transactions created with dmu_tx_create_assigned() from
1079 * syncing context don't bother holding ahead.
1081 ASSERT(db->db_level != 0 ||
1082 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
1083 db->db_state == DB_NOFILL);
1085 mutex_enter(&dn->dn_mtx);
1087 * Don't set dirtyctx to SYNC if we're just modifying this as we
1088 * initialize the objset.
1090 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
1091 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
1093 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
1094 ASSERT(dn->dn_dirtyctx_firstset == NULL);
1095 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_PUSHPAGE);
1097 mutex_exit(&dn->dn_mtx);
1099 if (db->db_blkid == DMU_SPILL_BLKID)
1100 dn->dn_have_spill = B_TRUE;
1103 * If this buffer is already dirty, we're done.
1105 drp = &db->db_last_dirty;
1106 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
1107 db->db.db_object == DMU_META_DNODE_OBJECT);
1108 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
1110 if (dr && dr->dr_txg == tx->tx_txg) {
1113 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
1115 * If this buffer has already been written out,
1116 * we now need to reset its state.
1118 dbuf_unoverride(dr);
1119 if (db->db.db_object != DMU_META_DNODE_OBJECT &&
1120 db->db_state != DB_NOFILL)
1121 arc_buf_thaw(db->db_buf);
1123 mutex_exit(&db->db_mtx);
1128 * Only valid if not already dirty.
1130 ASSERT(dn->dn_object == 0 ||
1131 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1132 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1134 ASSERT3U(dn->dn_nlevels, >, db->db_level);
1135 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
1136 dn->dn_phys->dn_nlevels > db->db_level ||
1137 dn->dn_next_nlevels[txgoff] > db->db_level ||
1138 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
1139 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
1142 * We should only be dirtying in syncing context if it's the
1143 * mos or we're initializing the os or it's a special object.
1144 * However, we are allowed to dirty in syncing context provided
1145 * we already dirtied it in open context. Hence we must make
1146 * this assertion only if we're not already dirty.
1149 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1150 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
1151 ASSERT(db->db.db_size != 0);
1153 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1155 if (db->db_blkid != DMU_BONUS_BLKID) {
1157 * Update the accounting.
1158 * Note: we delay "free accounting" until after we drop
1159 * the db_mtx. This keeps us from grabbing other locks
1160 * (and possibly deadlocking) in bp_get_dsize() while
1161 * also holding the db_mtx.
1163 dnode_willuse_space(dn, db->db.db_size, tx);
1164 do_free_accounting = dbuf_block_freeable(db);
1168 * If this buffer is dirty in an old transaction group we need
1169 * to make a copy of it so that the changes we make in this
1170 * transaction group won't leak out when we sync the older txg.
1172 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_PUSHPAGE);
1173 list_link_init(&dr->dr_dirty_node);
1174 if (db->db_level == 0) {
1175 void *data_old = db->db_buf;
1177 if (db->db_state != DB_NOFILL) {
1178 if (db->db_blkid == DMU_BONUS_BLKID) {
1179 dbuf_fix_old_data(db, tx->tx_txg);
1180 data_old = db->db.db_data;
1181 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1183 * Release the data buffer from the cache so
1184 * that we can modify it without impacting
1185 * possible other users of this cached data
1186 * block. Note that indirect blocks and
1187 * private objects are not released until the
1188 * syncing state (since they are only modified
1191 arc_release(db->db_buf, db);
1192 dbuf_fix_old_data(db, tx->tx_txg);
1193 data_old = db->db_buf;
1195 ASSERT(data_old != NULL);
1197 dr->dt.dl.dr_data = data_old;
1199 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1200 list_create(&dr->dt.di.dr_children,
1201 sizeof (dbuf_dirty_record_t),
1202 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1205 dr->dr_txg = tx->tx_txg;
1210 * We could have been freed_in_flight between the dbuf_noread
1211 * and dbuf_dirty. We win, as though the dbuf_noread() had
1212 * happened after the free.
1214 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1215 db->db_blkid != DMU_SPILL_BLKID) {
1216 mutex_enter(&dn->dn_mtx);
1217 dnode_clear_range(dn, db->db_blkid, 1, tx);
1218 mutex_exit(&dn->dn_mtx);
1219 db->db_freed_in_flight = FALSE;
1223 * This buffer is now part of this txg
1225 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1226 db->db_dirtycnt += 1;
1227 ASSERT3U(db->db_dirtycnt, <=, 3);
1229 mutex_exit(&db->db_mtx);
1231 if (db->db_blkid == DMU_BONUS_BLKID ||
1232 db->db_blkid == DMU_SPILL_BLKID) {
1233 mutex_enter(&dn->dn_mtx);
1234 ASSERT(!list_link_active(&dr->dr_dirty_node));
1235 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1236 mutex_exit(&dn->dn_mtx);
1237 dnode_setdirty(dn, tx);
1240 } else if (do_free_accounting) {
1241 blkptr_t *bp = db->db_blkptr;
1242 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1243 bp_get_dsize(os->os_spa, bp) : db->db.db_size;
1245 * This is only a guess -- if the dbuf is dirty
1246 * in a previous txg, we don't know how much
1247 * space it will use on disk yet. We should
1248 * really have the struct_rwlock to access
1249 * db_blkptr, but since this is just a guess,
1250 * it's OK if we get an odd answer.
1252 ddt_prefetch(os->os_spa, bp);
1253 dnode_willuse_space(dn, -willfree, tx);
1256 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1257 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1258 drop_struct_lock = TRUE;
1261 if (db->db_level == 0) {
1262 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1263 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1266 if (db->db_level+1 < dn->dn_nlevels) {
1267 dmu_buf_impl_t *parent = db->db_parent;
1268 dbuf_dirty_record_t *di;
1269 int parent_held = FALSE;
1271 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1272 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1274 parent = dbuf_hold_level(dn, db->db_level+1,
1275 db->db_blkid >> epbs, FTAG);
1276 ASSERT(parent != NULL);
1279 if (drop_struct_lock)
1280 rw_exit(&dn->dn_struct_rwlock);
1281 ASSERT3U(db->db_level+1, ==, parent->db_level);
1282 di = dbuf_dirty(parent, tx);
1284 dbuf_rele(parent, FTAG);
1286 mutex_enter(&db->db_mtx);
1287 /* possible race with dbuf_undirty() */
1288 if (db->db_last_dirty == dr ||
1289 dn->dn_object == DMU_META_DNODE_OBJECT) {
1290 mutex_enter(&di->dt.di.dr_mtx);
1291 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1292 ASSERT(!list_link_active(&dr->dr_dirty_node));
1293 list_insert_tail(&di->dt.di.dr_children, dr);
1294 mutex_exit(&di->dt.di.dr_mtx);
1297 mutex_exit(&db->db_mtx);
1299 ASSERT(db->db_level+1 == dn->dn_nlevels);
1300 ASSERT(db->db_blkid < dn->dn_nblkptr);
1301 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf);
1302 mutex_enter(&dn->dn_mtx);
1303 ASSERT(!list_link_active(&dr->dr_dirty_node));
1304 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1305 mutex_exit(&dn->dn_mtx);
1306 if (drop_struct_lock)
1307 rw_exit(&dn->dn_struct_rwlock);
1310 dnode_setdirty(dn, tx);
1316 * Return TRUE if this evicted the dbuf.
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);
1327 ASSERT0(db->db_level);
1328 ASSERT(MUTEX_HELD(&db->db_mtx));
1331 * If this buffer is not dirty, we're done.
1333 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1334 if (dr->dr_txg <= txg)
1336 if (dr == NULL || dr->dr_txg < txg)
1338 ASSERT(dr->dr_txg == txg);
1339 ASSERT(dr->dr_dbuf == db);
1345 * Note: This code will probably work even if there are concurrent
1346 * holders, but it is untested in that scenerio, as the ZPL and
1347 * ztest have additional locking (the range locks) that prevents
1348 * that type of concurrent access.
1350 ASSERT3U(refcount_count(&db->db_holds), ==, db->db_dirtycnt);
1352 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1354 ASSERT(db->db.db_size != 0);
1356 /* XXX would be nice to fix up dn_towrite_space[] */
1361 * Note that there are three places in dbuf_dirty()
1362 * where this dirty record may be put on a list.
1363 * Make sure to do a list_remove corresponding to
1364 * every one of those list_insert calls.
1366 if (dr->dr_parent) {
1367 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1368 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1369 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1370 } else if (db->db_blkid == DMU_SPILL_BLKID ||
1371 db->db_level+1 == dn->dn_nlevels) {
1372 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
1373 mutex_enter(&dn->dn_mtx);
1374 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
1375 mutex_exit(&dn->dn_mtx);
1379 if (db->db_state != DB_NOFILL) {
1380 dbuf_unoverride(dr);
1382 ASSERT(db->db_buf != NULL);
1383 ASSERT(dr->dt.dl.dr_data != NULL);
1384 if (dr->dt.dl.dr_data != db->db_buf)
1385 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db));
1387 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1389 ASSERT(db->db_dirtycnt > 0);
1390 db->db_dirtycnt -= 1;
1392 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1393 arc_buf_t *buf = db->db_buf;
1395 ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
1396 dbuf_set_data(db, NULL);
1397 VERIFY(arc_buf_remove_ref(buf, db));
1405 #pragma weak dmu_buf_will_dirty = dbuf_will_dirty
1407 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1409 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1411 ASSERT(tx->tx_txg != 0);
1412 ASSERT(!refcount_is_zero(&db->db_holds));
1415 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
1416 rf |= DB_RF_HAVESTRUCT;
1418 (void) dbuf_read(db, NULL, rf);
1419 (void) dbuf_dirty(db, tx);
1423 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1425 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1427 db->db_state = DB_NOFILL;
1429 dmu_buf_will_fill(db_fake, tx);
1433 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1435 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1437 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1438 ASSERT(tx->tx_txg != 0);
1439 ASSERT(db->db_level == 0);
1440 ASSERT(!refcount_is_zero(&db->db_holds));
1442 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1443 dmu_tx_private_ok(tx));
1446 (void) dbuf_dirty(db, tx);
1449 #pragma weak dmu_buf_fill_done = dbuf_fill_done
1452 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1454 mutex_enter(&db->db_mtx);
1457 if (db->db_state == DB_FILL) {
1458 if (db->db_level == 0 && db->db_freed_in_flight) {
1459 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1460 /* we were freed while filling */
1461 /* XXX dbuf_undirty? */
1462 bzero(db->db.db_data, db->db.db_size);
1463 db->db_freed_in_flight = FALSE;
1465 db->db_state = DB_CACHED;
1466 cv_broadcast(&db->db_changed);
1468 mutex_exit(&db->db_mtx);
1472 * Directly assign a provided arc buf to a given dbuf if it's not referenced
1473 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
1476 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
1478 ASSERT(!refcount_is_zero(&db->db_holds));
1479 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1480 ASSERT(db->db_level == 0);
1481 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
1482 ASSERT(buf != NULL);
1483 ASSERT(arc_buf_size(buf) == db->db.db_size);
1484 ASSERT(tx->tx_txg != 0);
1486 arc_return_buf(buf, db);
1487 ASSERT(arc_released(buf));
1489 mutex_enter(&db->db_mtx);
1491 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1492 cv_wait(&db->db_changed, &db->db_mtx);
1494 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
1496 if (db->db_state == DB_CACHED &&
1497 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
1498 mutex_exit(&db->db_mtx);
1499 (void) dbuf_dirty(db, tx);
1500 bcopy(buf->b_data, db->db.db_data, db->db.db_size);
1501 VERIFY(arc_buf_remove_ref(buf, db));
1502 xuio_stat_wbuf_copied();
1506 xuio_stat_wbuf_nocopy();
1507 if (db->db_state == DB_CACHED) {
1508 dbuf_dirty_record_t *dr = db->db_last_dirty;
1510 ASSERT(db->db_buf != NULL);
1511 if (dr != NULL && dr->dr_txg == tx->tx_txg) {
1512 ASSERT(dr->dt.dl.dr_data == db->db_buf);
1513 if (!arc_released(db->db_buf)) {
1514 ASSERT(dr->dt.dl.dr_override_state ==
1516 arc_release(db->db_buf, db);
1518 dr->dt.dl.dr_data = buf;
1519 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1520 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
1521 arc_release(db->db_buf, db);
1522 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1526 ASSERT(db->db_buf == NULL);
1527 dbuf_set_data(db, buf);
1528 db->db_state = DB_FILL;
1529 mutex_exit(&db->db_mtx);
1530 (void) dbuf_dirty(db, tx);
1531 dbuf_fill_done(db, tx);
1535 * "Clear" the contents of this dbuf. This will mark the dbuf
1536 * EVICTING and clear *most* of its references. Unfortunetely,
1537 * when we are not holding the dn_dbufs_mtx, we can't clear the
1538 * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
1539 * in this case. For callers from the DMU we will usually see:
1540 * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy()
1541 * For the arc callback, we will usually see:
1542 * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
1543 * Sometimes, though, we will get a mix of these two:
1544 * DMU: dbuf_clear()->arc_buf_evict()
1545 * ARC: dbuf_do_evict()->dbuf_destroy()
1548 dbuf_clear(dmu_buf_impl_t *db)
1551 dmu_buf_impl_t *parent = db->db_parent;
1552 dmu_buf_impl_t *dndb;
1553 int dbuf_gone = FALSE;
1555 ASSERT(MUTEX_HELD(&db->db_mtx));
1556 ASSERT(refcount_is_zero(&db->db_holds));
1558 dbuf_evict_user(db);
1560 if (db->db_state == DB_CACHED) {
1561 ASSERT(db->db.db_data != NULL);
1562 if (db->db_blkid == DMU_BONUS_BLKID) {
1563 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1564 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1566 db->db.db_data = NULL;
1567 db->db_state = DB_UNCACHED;
1570 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
1571 ASSERT(db->db_data_pending == NULL);
1573 db->db_state = DB_EVICTING;
1574 db->db_blkptr = NULL;
1579 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1580 list_remove(&dn->dn_dbufs, db);
1581 (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1585 * Decrementing the dbuf count means that the hold corresponding
1586 * to the removed dbuf is no longer discounted in dnode_move(),
1587 * so the dnode cannot be moved until after we release the hold.
1588 * The membar_producer() ensures visibility of the decremented
1589 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually
1593 db->db_dnode_handle = NULL;
1599 dbuf_gone = arc_buf_evict(db->db_buf);
1602 mutex_exit(&db->db_mtx);
1605 * If this dbuf is referenced from an indirect dbuf,
1606 * decrement the ref count on the indirect dbuf.
1608 if (parent && parent != dndb)
1609 dbuf_rele(parent, db);
1612 __attribute__((always_inline))
1614 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1615 dmu_buf_impl_t **parentp, blkptr_t **bpp, struct dbuf_hold_impl_data *dh)
1622 ASSERT(blkid != DMU_BONUS_BLKID);
1624 if (blkid == DMU_SPILL_BLKID) {
1625 mutex_enter(&dn->dn_mtx);
1626 if (dn->dn_have_spill &&
1627 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
1628 *bpp = &dn->dn_phys->dn_spill;
1631 dbuf_add_ref(dn->dn_dbuf, NULL);
1632 *parentp = dn->dn_dbuf;
1633 mutex_exit(&dn->dn_mtx);
1637 if (dn->dn_phys->dn_nlevels == 0)
1640 nlevels = dn->dn_phys->dn_nlevels;
1642 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1644 ASSERT3U(level * epbs, <, 64);
1645 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1646 if (level >= nlevels ||
1647 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
1648 /* the buffer has no parent yet */
1650 } else if (level < nlevels-1) {
1651 /* this block is referenced from an indirect block */
1654 err = dbuf_hold_impl(dn, level+1, blkid >> epbs,
1655 fail_sparse, NULL, parentp);
1658 __dbuf_hold_impl_init(dh + 1, dn, dh->dh_level + 1,
1659 blkid >> epbs, fail_sparse, NULL,
1660 parentp, dh->dh_depth + 1);
1661 err = __dbuf_hold_impl(dh + 1);
1665 err = dbuf_read(*parentp, NULL,
1666 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1668 dbuf_rele(*parentp, NULL);
1672 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1673 (blkid & ((1ULL << epbs) - 1));
1676 /* the block is referenced from the dnode */
1677 ASSERT3U(level, ==, nlevels-1);
1678 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1679 blkid < dn->dn_phys->dn_nblkptr);
1681 dbuf_add_ref(dn->dn_dbuf, NULL);
1682 *parentp = dn->dn_dbuf;
1684 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1689 static dmu_buf_impl_t *
1690 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1691 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1693 objset_t *os = dn->dn_objset;
1694 dmu_buf_impl_t *db, *odb;
1696 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1697 ASSERT(dn->dn_type != DMU_OT_NONE);
1699 db = kmem_cache_alloc(dbuf_cache, KM_PUSHPAGE);
1702 db->db.db_object = dn->dn_object;
1703 db->db_level = level;
1704 db->db_blkid = blkid;
1705 db->db_last_dirty = NULL;
1706 db->db_dirtycnt = 0;
1707 db->db_dnode_handle = dn->dn_handle;
1708 db->db_parent = parent;
1709 db->db_blkptr = blkptr;
1711 db->db_user_ptr = NULL;
1712 db->db_user_data_ptr_ptr = NULL;
1713 db->db_evict_func = NULL;
1714 db->db_immediate_evict = 0;
1715 db->db_freed_in_flight = 0;
1717 if (blkid == DMU_BONUS_BLKID) {
1718 ASSERT3P(parent, ==, dn->dn_dbuf);
1719 db->db.db_size = DN_MAX_BONUSLEN -
1720 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1721 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1722 db->db.db_offset = DMU_BONUS_BLKID;
1723 db->db_state = DB_UNCACHED;
1724 /* the bonus dbuf is not placed in the hash table */
1725 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1727 } else if (blkid == DMU_SPILL_BLKID) {
1728 db->db.db_size = (blkptr != NULL) ?
1729 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE;
1730 db->db.db_offset = 0;
1733 db->db_level ? 1<<dn->dn_indblkshift : dn->dn_datablksz;
1734 db->db.db_size = blocksize;
1735 db->db.db_offset = db->db_blkid * blocksize;
1739 * Hold the dn_dbufs_mtx while we get the new dbuf
1740 * in the hash table *and* added to the dbufs list.
1741 * This prevents a possible deadlock with someone
1742 * trying to look up this dbuf before its added to the
1745 mutex_enter(&dn->dn_dbufs_mtx);
1746 db->db_state = DB_EVICTING;
1747 if ((odb = dbuf_hash_insert(db)) != NULL) {
1748 /* someone else inserted it first */
1749 kmem_cache_free(dbuf_cache, db);
1750 mutex_exit(&dn->dn_dbufs_mtx);
1753 list_insert_head(&dn->dn_dbufs, db);
1754 db->db_state = DB_UNCACHED;
1755 mutex_exit(&dn->dn_dbufs_mtx);
1756 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1758 if (parent && parent != dn->dn_dbuf)
1759 dbuf_add_ref(parent, db);
1761 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1762 refcount_count(&dn->dn_holds) > 0);
1763 (void) refcount_add(&dn->dn_holds, db);
1764 (void) atomic_inc_32_nv(&dn->dn_dbufs_count);
1766 dprintf_dbuf(db, "db=%p\n", db);
1772 dbuf_do_evict(void *private)
1774 arc_buf_t *buf = private;
1775 dmu_buf_impl_t *db = buf->b_private;
1777 if (!MUTEX_HELD(&db->db_mtx))
1778 mutex_enter(&db->db_mtx);
1780 ASSERT(refcount_is_zero(&db->db_holds));
1782 if (db->db_state != DB_EVICTING) {
1783 ASSERT(db->db_state == DB_CACHED);
1788 mutex_exit(&db->db_mtx);
1795 dbuf_destroy(dmu_buf_impl_t *db)
1797 ASSERT(refcount_is_zero(&db->db_holds));
1799 if (db->db_blkid != DMU_BONUS_BLKID) {
1801 * If this dbuf is still on the dn_dbufs list,
1802 * remove it from that list.
1804 if (db->db_dnode_handle != NULL) {
1809 mutex_enter(&dn->dn_dbufs_mtx);
1810 list_remove(&dn->dn_dbufs, db);
1811 (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1812 mutex_exit(&dn->dn_dbufs_mtx);
1815 * Decrementing the dbuf count means that the hold
1816 * corresponding to the removed dbuf is no longer
1817 * discounted in dnode_move(), so the dnode cannot be
1818 * moved until after we release the hold.
1821 db->db_dnode_handle = NULL;
1823 dbuf_hash_remove(db);
1825 db->db_parent = NULL;
1828 ASSERT(!list_link_active(&db->db_link));
1829 ASSERT(db->db.db_data == NULL);
1830 ASSERT(db->db_hash_next == NULL);
1831 ASSERT(db->db_blkptr == NULL);
1832 ASSERT(db->db_data_pending == NULL);
1834 kmem_cache_free(dbuf_cache, db);
1835 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1839 dbuf_prefetch(dnode_t *dn, uint64_t blkid)
1841 dmu_buf_impl_t *db = NULL;
1842 blkptr_t *bp = NULL;
1844 ASSERT(blkid != DMU_BONUS_BLKID);
1845 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1847 if (dnode_block_freed(dn, blkid))
1850 /* dbuf_find() returns with db_mtx held */
1851 if ((db = dbuf_find(dn, 0, blkid))) {
1853 * This dbuf is already in the cache. We assume that
1854 * it is already CACHED, or else about to be either
1857 mutex_exit(&db->db_mtx);
1861 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp, NULL) == 0) {
1862 if (bp && !BP_IS_HOLE(bp)) {
1863 int priority = dn->dn_type == DMU_OT_DDT_ZAP ?
1864 ZIO_PRIORITY_DDT_PREFETCH : ZIO_PRIORITY_ASYNC_READ;
1865 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
1866 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
1869 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1870 dn->dn_object, 0, blkid);
1872 (void) arc_read(NULL, dn->dn_objset->os_spa,
1873 bp, NULL, NULL, priority,
1874 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1878 dbuf_rele(db, NULL);
1882 #define DBUF_HOLD_IMPL_MAX_DEPTH 20
1885 * Returns with db_holds incremented, and db_mtx not held.
1886 * Note: dn_struct_rwlock must be held.
1889 __dbuf_hold_impl(struct dbuf_hold_impl_data *dh)
1891 ASSERT3S(dh->dh_depth, <, DBUF_HOLD_IMPL_MAX_DEPTH);
1892 dh->dh_parent = NULL;
1894 ASSERT(dh->dh_blkid != DMU_BONUS_BLKID);
1895 ASSERT(RW_LOCK_HELD(&dh->dh_dn->dn_struct_rwlock));
1896 ASSERT3U(dh->dh_dn->dn_nlevels, >, dh->dh_level);
1898 *(dh->dh_dbp) = NULL;
1900 /* dbuf_find() returns with db_mtx held */
1901 dh->dh_db = dbuf_find(dh->dh_dn, dh->dh_level, dh->dh_blkid);
1903 if (dh->dh_db == NULL) {
1906 ASSERT3P(dh->dh_parent, ==, NULL);
1907 dh->dh_err = dbuf_findbp(dh->dh_dn, dh->dh_level, dh->dh_blkid,
1908 dh->dh_fail_sparse, &dh->dh_parent,
1910 if (dh->dh_fail_sparse) {
1911 if (dh->dh_err == 0 && dh->dh_bp && BP_IS_HOLE(dh->dh_bp))
1912 dh->dh_err = ENOENT;
1915 dbuf_rele(dh->dh_parent, NULL);
1916 return (dh->dh_err);
1919 if (dh->dh_err && dh->dh_err != ENOENT)
1920 return (dh->dh_err);
1921 dh->dh_db = dbuf_create(dh->dh_dn, dh->dh_level, dh->dh_blkid,
1922 dh->dh_parent, dh->dh_bp);
1925 if (dh->dh_db->db_buf && refcount_is_zero(&dh->dh_db->db_holds)) {
1926 arc_buf_add_ref(dh->dh_db->db_buf, dh->dh_db);
1927 if (dh->dh_db->db_buf->b_data == NULL) {
1928 dbuf_clear(dh->dh_db);
1929 if (dh->dh_parent) {
1930 dbuf_rele(dh->dh_parent, NULL);
1931 dh->dh_parent = NULL;
1935 ASSERT3P(dh->dh_db->db.db_data, ==, dh->dh_db->db_buf->b_data);
1938 ASSERT(dh->dh_db->db_buf == NULL || arc_referenced(dh->dh_db->db_buf));
1941 * If this buffer is currently syncing out, and we are are
1942 * still referencing it from db_data, we need to make a copy
1943 * of it in case we decide we want to dirty it again in this txg.
1945 if (dh->dh_db->db_level == 0 &&
1946 dh->dh_db->db_blkid != DMU_BONUS_BLKID &&
1947 dh->dh_dn->dn_object != DMU_META_DNODE_OBJECT &&
1948 dh->dh_db->db_state == DB_CACHED && dh->dh_db->db_data_pending) {
1949 dh->dh_dr = dh->dh_db->db_data_pending;
1951 if (dh->dh_dr->dt.dl.dr_data == dh->dh_db->db_buf) {
1952 dh->dh_type = DBUF_GET_BUFC_TYPE(dh->dh_db);
1954 dbuf_set_data(dh->dh_db,
1955 arc_buf_alloc(dh->dh_dn->dn_objset->os_spa,
1956 dh->dh_db->db.db_size, dh->dh_db, dh->dh_type));
1957 bcopy(dh->dh_dr->dt.dl.dr_data->b_data,
1958 dh->dh_db->db.db_data, dh->dh_db->db.db_size);
1962 (void) refcount_add(&dh->dh_db->db_holds, dh->dh_tag);
1963 dbuf_update_data(dh->dh_db);
1964 DBUF_VERIFY(dh->dh_db);
1965 mutex_exit(&dh->dh_db->db_mtx);
1967 /* NOTE: we can't rele the parent until after we drop the db_mtx */
1969 dbuf_rele(dh->dh_parent, NULL);
1971 ASSERT3P(DB_DNODE(dh->dh_db), ==, dh->dh_dn);
1972 ASSERT3U(dh->dh_db->db_blkid, ==, dh->dh_blkid);
1973 ASSERT3U(dh->dh_db->db_level, ==, dh->dh_level);
1974 *(dh->dh_dbp) = dh->dh_db;
1980 * The following code preserves the recursive function dbuf_hold_impl()
1981 * but moves the local variables AND function arguments to the heap to
1982 * minimize the stack frame size. Enough space is initially allocated
1983 * on the stack for 20 levels of recursion.
1986 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
1987 void *tag, dmu_buf_impl_t **dbp)
1989 struct dbuf_hold_impl_data *dh;
1992 dh = kmem_zalloc(sizeof(struct dbuf_hold_impl_data) *
1993 DBUF_HOLD_IMPL_MAX_DEPTH, KM_PUSHPAGE);
1994 __dbuf_hold_impl_init(dh, dn, level, blkid, fail_sparse, tag, dbp, 0);
1996 error = __dbuf_hold_impl(dh);
1998 kmem_free(dh, sizeof(struct dbuf_hold_impl_data) *
1999 DBUF_HOLD_IMPL_MAX_DEPTH);
2005 __dbuf_hold_impl_init(struct dbuf_hold_impl_data *dh,
2006 dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
2007 void *tag, dmu_buf_impl_t **dbp, int depth)
2010 dh->dh_level = level;
2011 dh->dh_blkid = blkid;
2012 dh->dh_fail_sparse = fail_sparse;
2015 dh->dh_depth = depth;
2019 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
2022 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
2023 return (err ? NULL : db);
2027 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
2030 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
2031 return (err ? NULL : db);
2035 dbuf_create_bonus(dnode_t *dn)
2037 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
2039 ASSERT(dn->dn_bonus == NULL);
2040 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL);
2044 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx)
2046 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2049 if (db->db_blkid != DMU_SPILL_BLKID)
2052 blksz = SPA_MINBLOCKSIZE;
2053 if (blksz > SPA_MAXBLOCKSIZE)
2054 blksz = SPA_MAXBLOCKSIZE;
2056 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE);
2060 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
2061 dbuf_new_size(db, blksz, tx);
2062 rw_exit(&dn->dn_struct_rwlock);
2069 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx)
2071 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx);
2074 #pragma weak dmu_buf_add_ref = dbuf_add_ref
2076 dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
2078 VERIFY(refcount_add(&db->db_holds, tag) > 1);
2082 * If you call dbuf_rele() you had better not be referencing the dnode handle
2083 * unless you have some other direct or indirect hold on the dnode. (An indirect
2084 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.)
2085 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the
2086 * dnode's parent dbuf evicting its dnode handles.
2088 #pragma weak dmu_buf_rele = dbuf_rele
2090 dbuf_rele(dmu_buf_impl_t *db, void *tag)
2092 mutex_enter(&db->db_mtx);
2093 dbuf_rele_and_unlock(db, tag);
2097 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
2098 * db_dirtycnt and db_holds to be updated atomically.
2101 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
2105 ASSERT(MUTEX_HELD(&db->db_mtx));
2109 * Remove the reference to the dbuf before removing its hold on the
2110 * dnode so we can guarantee in dnode_move() that a referenced bonus
2111 * buffer has a corresponding dnode hold.
2113 holds = refcount_remove(&db->db_holds, tag);
2117 * We can't freeze indirects if there is a possibility that they
2118 * may be modified in the current syncing context.
2120 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
2121 arc_buf_freeze(db->db_buf);
2123 if (holds == db->db_dirtycnt &&
2124 db->db_level == 0 && db->db_immediate_evict)
2125 dbuf_evict_user(db);
2128 if (db->db_blkid == DMU_BONUS_BLKID) {
2129 mutex_exit(&db->db_mtx);
2132 * If the dnode moves here, we cannot cross this barrier
2133 * until the move completes.
2136 (void) atomic_dec_32_nv(&DB_DNODE(db)->dn_dbufs_count);
2139 * The bonus buffer's dnode hold is no longer discounted
2140 * in dnode_move(). The dnode cannot move until after
2143 dnode_rele(DB_DNODE(db), db);
2144 } else if (db->db_buf == NULL) {
2146 * This is a special case: we never associated this
2147 * dbuf with any data allocated from the ARC.
2149 ASSERT(db->db_state == DB_UNCACHED ||
2150 db->db_state == DB_NOFILL);
2152 } else if (arc_released(db->db_buf)) {
2153 arc_buf_t *buf = db->db_buf;
2155 * This dbuf has anonymous data associated with it.
2157 dbuf_set_data(db, NULL);
2158 VERIFY(arc_buf_remove_ref(buf, db));
2161 VERIFY(!arc_buf_remove_ref(db->db_buf, db));
2164 * A dbuf will be eligible for eviction if either the
2165 * 'primarycache' property is set or a duplicate
2166 * copy of this buffer is already cached in the arc.
2168 * In the case of the 'primarycache' a buffer
2169 * is considered for eviction if it matches the
2170 * criteria set in the property.
2172 * To decide if our buffer is considered a
2173 * duplicate, we must call into the arc to determine
2174 * if multiple buffers are referencing the same
2175 * block on-disk. If so, then we simply evict
2178 if (!DBUF_IS_CACHEABLE(db) ||
2179 arc_buf_eviction_needed(db->db_buf))
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 ASSERT0(db->db_level);
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 ASSERT0(zio->io_error);
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),
2816 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready,
2817 dbuf_write_done, db, ZIO_PRIORITY_ASYNC_WRITE,
2818 ZIO_FLAG_MUSTSUCCEED, &zb);
2822 #if defined(_KERNEL) && defined(HAVE_SPL)
2823 EXPORT_SYMBOL(dbuf_find);
2824 EXPORT_SYMBOL(dbuf_is_metadata);
2825 EXPORT_SYMBOL(dbuf_evict);
2826 EXPORT_SYMBOL(dbuf_loan_arcbuf);
2827 EXPORT_SYMBOL(dbuf_whichblock);
2828 EXPORT_SYMBOL(dbuf_read);
2829 EXPORT_SYMBOL(dbuf_unoverride);
2830 EXPORT_SYMBOL(dbuf_free_range);
2831 EXPORT_SYMBOL(dbuf_new_size);
2832 EXPORT_SYMBOL(dbuf_release_bp);
2833 EXPORT_SYMBOL(dbuf_dirty);
2834 EXPORT_SYMBOL(dmu_buf_will_dirty);
2835 EXPORT_SYMBOL(dmu_buf_will_not_fill);
2836 EXPORT_SYMBOL(dmu_buf_will_fill);
2837 EXPORT_SYMBOL(dmu_buf_fill_done);
2838 EXPORT_SYMBOL(dmu_buf_rele);
2839 EXPORT_SYMBOL(dbuf_assign_arcbuf);
2840 EXPORT_SYMBOL(dbuf_clear);
2841 EXPORT_SYMBOL(dbuf_prefetch);
2842 EXPORT_SYMBOL(dbuf_hold_impl);
2843 EXPORT_SYMBOL(dbuf_hold);
2844 EXPORT_SYMBOL(dbuf_hold_level);
2845 EXPORT_SYMBOL(dbuf_create_bonus);
2846 EXPORT_SYMBOL(dbuf_spill_set_blksz);
2847 EXPORT_SYMBOL(dbuf_rm_spill);
2848 EXPORT_SYMBOL(dbuf_add_ref);
2849 EXPORT_SYMBOL(dbuf_rele);
2850 EXPORT_SYMBOL(dbuf_rele_and_unlock);
2851 EXPORT_SYMBOL(dbuf_refcount);
2852 EXPORT_SYMBOL(dbuf_sync_list);
2853 EXPORT_SYMBOL(dmu_buf_set_user);
2854 EXPORT_SYMBOL(dmu_buf_set_user_ie);
2855 EXPORT_SYMBOL(dmu_buf_update_user);
2856 EXPORT_SYMBOL(dmu_buf_get_user);
2857 EXPORT_SYMBOL(dmu_buf_freeable);