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>
27 #include <sys/dmu_impl.h>
29 #include <sys/dmu_objset.h>
30 #include <sys/dsl_dataset.h>
31 #include <sys/dsl_dir.h>
32 #include <sys/dmu_tx.h>
35 #include <sys/dmu_zfetch.h>
37 #include <sys/sa_impl.h>
39 struct dbuf_hold_impl_data {
40 /* Function arguments */
46 dmu_buf_impl_t **dh_dbp;
48 dmu_buf_impl_t *dh_db;
49 dmu_buf_impl_t *dh_parent;
52 dbuf_dirty_record_t *dh_dr;
53 arc_buf_contents_t dh_type;
57 static void __dbuf_hold_impl_init(struct dbuf_hold_impl_data *dh,
58 dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
59 void *tag, dmu_buf_impl_t **dbp, int depth);
60 static int __dbuf_hold_impl(struct dbuf_hold_impl_data *dh);
62 static void dbuf_destroy(dmu_buf_impl_t *db);
63 static int dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
64 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
67 * Global data structures and functions for the dbuf cache.
69 static kmem_cache_t *dbuf_cache;
73 dbuf_cons(void *vdb, void *unused, int kmflag)
75 dmu_buf_impl_t *db = vdb;
76 bzero(db, sizeof (dmu_buf_impl_t));
78 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
79 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
80 refcount_create(&db->db_holds);
81 list_link_init(&db->db_link);
87 dbuf_dest(void *vdb, void *unused)
89 dmu_buf_impl_t *db = vdb;
90 mutex_destroy(&db->db_mtx);
91 cv_destroy(&db->db_changed);
92 refcount_destroy(&db->db_holds);
96 * dbuf hash table routines
98 static dbuf_hash_table_t dbuf_hash_table;
100 static uint64_t dbuf_hash_count;
103 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
105 uintptr_t osv = (uintptr_t)os;
106 uint64_t crc = -1ULL;
108 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
109 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
110 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
111 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
112 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
113 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
114 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
116 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
121 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
123 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
124 ((dbuf)->db.db_object == (obj) && \
125 (dbuf)->db_objset == (os) && \
126 (dbuf)->db_level == (level) && \
127 (dbuf)->db_blkid == (blkid))
130 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
132 dbuf_hash_table_t *h = &dbuf_hash_table;
133 objset_t *os = dn->dn_objset;
140 hv = DBUF_HASH(os, obj, level, blkid);
141 idx = hv & h->hash_table_mask;
143 mutex_enter(DBUF_HASH_MUTEX(h, idx));
144 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
145 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
146 mutex_enter(&db->db_mtx);
147 if (db->db_state != DB_EVICTING) {
148 mutex_exit(DBUF_HASH_MUTEX(h, idx));
151 mutex_exit(&db->db_mtx);
154 mutex_exit(DBUF_HASH_MUTEX(h, idx));
159 * Insert an entry into the hash table. If there is already an element
160 * equal to elem in the hash table, then the already existing element
161 * will be returned and the new element will not be inserted.
162 * Otherwise returns NULL.
164 static dmu_buf_impl_t *
165 dbuf_hash_insert(dmu_buf_impl_t *db)
167 dbuf_hash_table_t *h = &dbuf_hash_table;
168 objset_t *os = db->db_objset;
169 uint64_t obj = db->db.db_object;
170 int level = db->db_level;
171 uint64_t blkid, hv, idx;
174 blkid = db->db_blkid;
175 hv = DBUF_HASH(os, obj, level, blkid);
176 idx = hv & h->hash_table_mask;
178 mutex_enter(DBUF_HASH_MUTEX(h, idx));
179 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
180 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
181 mutex_enter(&dbf->db_mtx);
182 if (dbf->db_state != DB_EVICTING) {
183 mutex_exit(DBUF_HASH_MUTEX(h, idx));
186 mutex_exit(&dbf->db_mtx);
190 mutex_enter(&db->db_mtx);
191 db->db_hash_next = h->hash_table[idx];
192 h->hash_table[idx] = db;
193 mutex_exit(DBUF_HASH_MUTEX(h, idx));
194 atomic_add_64(&dbuf_hash_count, 1);
200 * Remove an entry from the hash table. This operation will
201 * fail if there are any existing holds on the db.
204 dbuf_hash_remove(dmu_buf_impl_t *db)
206 dbuf_hash_table_t *h = &dbuf_hash_table;
208 dmu_buf_impl_t *dbf, **dbp;
210 hv = DBUF_HASH(db->db_objset, db->db.db_object,
211 db->db_level, db->db_blkid);
212 idx = hv & h->hash_table_mask;
215 * We musn't hold db_mtx to maintin lock ordering:
216 * DBUF_HASH_MUTEX > db_mtx.
218 ASSERT(refcount_is_zero(&db->db_holds));
219 ASSERT(db->db_state == DB_EVICTING);
220 ASSERT(!MUTEX_HELD(&db->db_mtx));
222 mutex_enter(DBUF_HASH_MUTEX(h, idx));
223 dbp = &h->hash_table[idx];
224 while ((dbf = *dbp) != db) {
225 dbp = &dbf->db_hash_next;
228 *dbp = db->db_hash_next;
229 db->db_hash_next = NULL;
230 mutex_exit(DBUF_HASH_MUTEX(h, idx));
231 atomic_add_64(&dbuf_hash_count, -1);
234 static arc_evict_func_t dbuf_do_evict;
237 dbuf_evict_user(dmu_buf_impl_t *db)
239 ASSERT(MUTEX_HELD(&db->db_mtx));
241 if (db->db_level != 0 || db->db_evict_func == NULL)
244 if (db->db_user_data_ptr_ptr)
245 *db->db_user_data_ptr_ptr = db->db.db_data;
246 db->db_evict_func(&db->db, db->db_user_ptr);
247 db->db_user_ptr = NULL;
248 db->db_user_data_ptr_ptr = NULL;
249 db->db_evict_func = NULL;
253 dbuf_is_metadata(dmu_buf_impl_t *db)
255 if (db->db_level > 0) {
258 boolean_t is_metadata;
261 is_metadata = dmu_ot[DB_DNODE(db)->dn_type].ot_metadata;
264 return (is_metadata);
269 dbuf_evict(dmu_buf_impl_t *db)
271 ASSERT(MUTEX_HELD(&db->db_mtx));
272 ASSERT(db->db_buf == NULL);
273 ASSERT(db->db_data_pending == NULL);
282 uint64_t hsize = 1ULL << 16;
283 dbuf_hash_table_t *h = &dbuf_hash_table;
287 * The hash table is big enough to fill all of physical memory
288 * with an average 4K block size. The table will take up
289 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
291 while (hsize * 4096 < physmem * PAGESIZE)
295 h->hash_table_mask = hsize - 1;
296 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
297 if (h->hash_table == NULL) {
298 /* XXX - we should really return an error instead of assert */
299 ASSERT(hsize > (1ULL << 10));
304 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
305 sizeof (dmu_buf_impl_t),
306 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
308 for (i = 0; i < DBUF_MUTEXES; i++)
309 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
315 dbuf_hash_table_t *h = &dbuf_hash_table;
318 for (i = 0; i < DBUF_MUTEXES; i++)
319 mutex_destroy(&h->hash_mutexes[i]);
320 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
321 kmem_cache_destroy(dbuf_cache);
330 dbuf_verify(dmu_buf_impl_t *db)
333 dbuf_dirty_record_t *dr;
335 ASSERT(MUTEX_HELD(&db->db_mtx));
337 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
340 ASSERT(db->db_objset != NULL);
344 ASSERT(db->db_parent == NULL);
345 ASSERT(db->db_blkptr == NULL);
347 ASSERT3U(db->db.db_object, ==, dn->dn_object);
348 ASSERT3P(db->db_objset, ==, dn->dn_objset);
349 ASSERT3U(db->db_level, <, dn->dn_nlevels);
350 ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
351 db->db_blkid == DMU_SPILL_BLKID ||
352 !list_is_empty(&dn->dn_dbufs));
354 if (db->db_blkid == DMU_BONUS_BLKID) {
356 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
357 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID);
358 } else if (db->db_blkid == DMU_SPILL_BLKID) {
360 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
361 ASSERT3U(db->db.db_offset, ==, 0);
363 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
366 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
367 ASSERT(dr->dr_dbuf == db);
369 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
370 ASSERT(dr->dr_dbuf == db);
373 * We can't assert that db_size matches dn_datablksz because it
374 * can be momentarily different when another thread is doing
377 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
378 dr = db->db_data_pending;
380 * It should only be modified in syncing context, so
381 * make sure we only have one copy of the data.
383 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
386 /* verify db->db_blkptr */
388 if (db->db_parent == dn->dn_dbuf) {
389 /* db is pointed to by the dnode */
390 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
391 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
392 ASSERT(db->db_parent == NULL);
394 ASSERT(db->db_parent != NULL);
395 if (db->db_blkid != DMU_SPILL_BLKID)
396 ASSERT3P(db->db_blkptr, ==,
397 &dn->dn_phys->dn_blkptr[db->db_blkid]);
399 /* db is pointed to by an indirect block */
400 ASSERTV(int epb = db->db_parent->db.db_size >>
402 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
403 ASSERT3U(db->db_parent->db.db_object, ==,
406 * dnode_grow_indblksz() can make this fail if we don't
407 * have the struct_rwlock. XXX indblksz no longer
408 * grows. safe to do this now?
410 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
411 ASSERT3P(db->db_blkptr, ==,
412 ((blkptr_t *)db->db_parent->db.db_data +
413 db->db_blkid % epb));
417 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
418 (db->db_buf == NULL || db->db_buf->b_data) &&
419 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID &&
420 db->db_state != DB_FILL && !dn->dn_free_txg) {
422 * If the blkptr isn't set but they have nonzero data,
423 * it had better be dirty, otherwise we'll lose that
424 * data when we evict this buffer.
426 if (db->db_dirtycnt == 0) {
427 ASSERTV(uint64_t *buf = db->db.db_data);
430 for (i = 0; i < db->db.db_size >> 3; i++) {
440 dbuf_update_data(dmu_buf_impl_t *db)
442 ASSERT(MUTEX_HELD(&db->db_mtx));
443 if (db->db_level == 0 && db->db_user_data_ptr_ptr) {
444 ASSERT(!refcount_is_zero(&db->db_holds));
445 *db->db_user_data_ptr_ptr = db->db.db_data;
450 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
452 ASSERT(MUTEX_HELD(&db->db_mtx));
453 ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf));
456 ASSERT(buf->b_data != NULL);
457 db->db.db_data = buf->b_data;
458 if (!arc_released(buf))
459 arc_set_callback(buf, dbuf_do_evict, db);
460 dbuf_update_data(db);
463 db->db.db_data = NULL;
464 if (db->db_state != DB_NOFILL)
465 db->db_state = DB_UNCACHED;
470 * Loan out an arc_buf for read. Return the loaned arc_buf.
473 dbuf_loan_arcbuf(dmu_buf_impl_t *db)
477 mutex_enter(&db->db_mtx);
478 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
479 int blksz = db->db.db_size;
482 mutex_exit(&db->db_mtx);
483 DB_GET_SPA(&spa, db);
484 abuf = arc_loan_buf(spa, blksz);
485 bcopy(db->db.db_data, abuf->b_data, blksz);
488 arc_loan_inuse_buf(abuf, db);
489 dbuf_set_data(db, NULL);
490 mutex_exit(&db->db_mtx);
496 dbuf_whichblock(dnode_t *dn, uint64_t offset)
498 if (dn->dn_datablkshift) {
499 return (offset >> dn->dn_datablkshift);
501 ASSERT3U(offset, <, dn->dn_datablksz);
507 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
509 dmu_buf_impl_t *db = vdb;
511 mutex_enter(&db->db_mtx);
512 ASSERT3U(db->db_state, ==, DB_READ);
514 * All reads are synchronous, so we must have a hold on the dbuf
516 ASSERT(refcount_count(&db->db_holds) > 0);
517 ASSERT(db->db_buf == NULL);
518 ASSERT(db->db.db_data == NULL);
519 if (db->db_level == 0 && db->db_freed_in_flight) {
520 /* we were freed in flight; disregard any error */
521 arc_release(buf, db);
522 bzero(buf->b_data, db->db.db_size);
524 db->db_freed_in_flight = FALSE;
525 dbuf_set_data(db, buf);
526 db->db_state = DB_CACHED;
527 } else if (zio == NULL || zio->io_error == 0) {
528 dbuf_set_data(db, buf);
529 db->db_state = DB_CACHED;
531 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
532 ASSERT3P(db->db_buf, ==, NULL);
533 VERIFY(arc_buf_remove_ref(buf, db) == 1);
534 db->db_state = DB_UNCACHED;
536 cv_broadcast(&db->db_changed);
537 dbuf_rele_and_unlock(db, NULL);
541 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
546 uint32_t aflags = ARC_NOWAIT;
551 ASSERT(!refcount_is_zero(&db->db_holds));
552 /* We need the struct_rwlock to prevent db_blkptr from changing. */
553 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
554 ASSERT(MUTEX_HELD(&db->db_mtx));
555 ASSERT(db->db_state == DB_UNCACHED);
556 ASSERT(db->db_buf == NULL);
558 if (db->db_blkid == DMU_BONUS_BLKID) {
559 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
561 ASSERT3U(bonuslen, <=, db->db.db_size);
562 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
563 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
564 if (bonuslen < DN_MAX_BONUSLEN)
565 bzero(db->db.db_data, DN_MAX_BONUSLEN);
567 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
569 dbuf_update_data(db);
570 db->db_state = DB_CACHED;
571 mutex_exit(&db->db_mtx);
576 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
577 * processes the delete record and clears the bp while we are waiting
578 * for the dn_mtx (resulting in a "no" from block_freed).
580 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
581 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
582 BP_IS_HOLE(db->db_blkptr)))) {
583 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
585 dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa,
586 db->db.db_size, db, type));
588 bzero(db->db.db_data, db->db.db_size);
589 db->db_state = DB_CACHED;
590 *flags |= DB_RF_CACHED;
591 mutex_exit(&db->db_mtx);
595 spa = dn->dn_objset->os_spa;
598 db->db_state = DB_READ;
599 mutex_exit(&db->db_mtx);
601 if (DBUF_IS_L2CACHEABLE(db))
602 aflags |= ARC_L2CACHE;
604 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
605 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
606 db->db.db_object, db->db_level, db->db_blkid);
608 dbuf_add_ref(db, NULL);
609 /* ZIO_FLAG_CANFAIL callers have to check the parent zio's error */
612 pbuf = db->db_parent->db_buf;
614 pbuf = db->db_objset->os_phys_buf;
616 (void) dsl_read(zio, spa, db->db_blkptr, pbuf,
617 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
618 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
620 if (aflags & ARC_CACHED)
621 *flags |= DB_RF_CACHED;
625 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
628 int havepzio = (zio != NULL);
633 * We don't have to hold the mutex to check db_state because it
634 * can't be freed while we have a hold on the buffer.
636 ASSERT(!refcount_is_zero(&db->db_holds));
638 if (db->db_state == DB_NOFILL)
643 if ((flags & DB_RF_HAVESTRUCT) == 0)
644 rw_enter(&dn->dn_struct_rwlock, RW_READER);
646 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
647 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL &&
648 DBUF_IS_CACHEABLE(db);
650 mutex_enter(&db->db_mtx);
651 if (db->db_state == DB_CACHED) {
652 mutex_exit(&db->db_mtx);
654 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
655 db->db.db_size, TRUE);
656 if ((flags & DB_RF_HAVESTRUCT) == 0)
657 rw_exit(&dn->dn_struct_rwlock);
659 } else if (db->db_state == DB_UNCACHED) {
660 spa_t *spa = dn->dn_objset->os_spa;
663 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
664 dbuf_read_impl(db, zio, &flags);
666 /* dbuf_read_impl has dropped db_mtx for us */
669 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
670 db->db.db_size, flags & DB_RF_CACHED);
672 if ((flags & DB_RF_HAVESTRUCT) == 0)
673 rw_exit(&dn->dn_struct_rwlock);
679 mutex_exit(&db->db_mtx);
681 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
682 db->db.db_size, TRUE);
683 if ((flags & DB_RF_HAVESTRUCT) == 0)
684 rw_exit(&dn->dn_struct_rwlock);
687 mutex_enter(&db->db_mtx);
688 if ((flags & DB_RF_NEVERWAIT) == 0) {
689 while (db->db_state == DB_READ ||
690 db->db_state == DB_FILL) {
691 ASSERT(db->db_state == DB_READ ||
692 (flags & DB_RF_HAVESTRUCT) == 0);
693 cv_wait(&db->db_changed, &db->db_mtx);
695 if (db->db_state == DB_UNCACHED)
698 mutex_exit(&db->db_mtx);
701 ASSERT(err || havepzio || db->db_state == DB_CACHED);
706 dbuf_noread(dmu_buf_impl_t *db)
708 ASSERT(!refcount_is_zero(&db->db_holds));
709 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
710 mutex_enter(&db->db_mtx);
711 while (db->db_state == DB_READ || db->db_state == DB_FILL)
712 cv_wait(&db->db_changed, &db->db_mtx);
713 if (db->db_state == DB_UNCACHED) {
714 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
717 ASSERT(db->db_buf == NULL);
718 ASSERT(db->db.db_data == NULL);
719 DB_GET_SPA(&spa, db);
720 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type));
721 db->db_state = DB_FILL;
722 } else if (db->db_state == DB_NOFILL) {
723 dbuf_set_data(db, NULL);
725 ASSERT3U(db->db_state, ==, DB_CACHED);
727 mutex_exit(&db->db_mtx);
731 * This is our just-in-time copy function. It makes a copy of
732 * buffers, that have been modified in a previous transaction
733 * group, before we modify them in the current active group.
735 * This function is used in two places: when we are dirtying a
736 * buffer for the first time in a txg, and when we are freeing
737 * a range in a dnode that includes this buffer.
739 * Note that when we are called from dbuf_free_range() we do
740 * not put a hold on the buffer, we just traverse the active
741 * dbuf list for the dnode.
744 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
746 dbuf_dirty_record_t *dr = db->db_last_dirty;
748 ASSERT(MUTEX_HELD(&db->db_mtx));
749 ASSERT(db->db.db_data != NULL);
750 ASSERT(db->db_level == 0);
751 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT);
754 (dr->dt.dl.dr_data !=
755 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf)))
759 * If the last dirty record for this dbuf has not yet synced
760 * and its referencing the dbuf data, either:
761 * reset the reference to point to a new copy,
762 * or (if there a no active holders)
763 * just null out the current db_data pointer.
765 ASSERT(dr->dr_txg >= txg - 2);
766 if (db->db_blkid == DMU_BONUS_BLKID) {
767 /* Note that the data bufs here are zio_bufs */
768 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
769 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
770 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
771 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
772 int size = db->db.db_size;
773 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
776 DB_GET_SPA(&spa, db);
777 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type);
778 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
780 dbuf_set_data(db, NULL);
785 dbuf_unoverride(dbuf_dirty_record_t *dr)
787 dmu_buf_impl_t *db = dr->dr_dbuf;
788 blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
789 uint64_t txg = dr->dr_txg;
791 ASSERT(MUTEX_HELD(&db->db_mtx));
792 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
793 ASSERT(db->db_level == 0);
795 if (db->db_blkid == DMU_BONUS_BLKID ||
796 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
799 ASSERT(db->db_data_pending != dr);
801 /* free this block */
802 if (!BP_IS_HOLE(bp)) {
805 DB_GET_SPA(&spa, db);
806 zio_free(spa, txg, bp);
808 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
810 * Release the already-written buffer, so we leave it in
811 * a consistent dirty state. Note that all callers are
812 * modifying the buffer, so they will immediately do
813 * another (redundant) arc_release(). Therefore, leave
814 * the buf thawed to save the effort of freezing &
815 * immediately re-thawing it.
817 arc_release(dr->dt.dl.dr_data, db);
821 * Evict (if its unreferenced) or clear (if its referenced) any level-0
822 * data blocks in the free range, so that any future readers will find
823 * empty blocks. Also, if we happen accross any level-1 dbufs in the
824 * range that have not already been marked dirty, mark them dirty so
825 * they stay in memory.
828 dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
830 dmu_buf_impl_t *db, *db_next;
831 uint64_t txg = tx->tx_txg;
832 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
833 uint64_t first_l1 = start >> epbs;
834 uint64_t last_l1 = end >> epbs;
836 if (end > dn->dn_maxblkid && (end != DMU_SPILL_BLKID)) {
837 end = dn->dn_maxblkid;
838 last_l1 = end >> epbs;
840 dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
841 mutex_enter(&dn->dn_dbufs_mtx);
842 for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
843 db_next = list_next(&dn->dn_dbufs, db);
844 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
846 if (db->db_level == 1 &&
847 db->db_blkid >= first_l1 && db->db_blkid <= last_l1) {
848 mutex_enter(&db->db_mtx);
849 if (db->db_last_dirty &&
850 db->db_last_dirty->dr_txg < txg) {
851 dbuf_add_ref(db, FTAG);
852 mutex_exit(&db->db_mtx);
853 dbuf_will_dirty(db, tx);
856 mutex_exit(&db->db_mtx);
860 if (db->db_level != 0)
862 dprintf_dbuf(db, "found buf %s\n", "");
863 if (db->db_blkid < start || db->db_blkid > end)
866 /* found a level 0 buffer in the range */
867 if (dbuf_undirty(db, tx))
870 mutex_enter(&db->db_mtx);
871 if (db->db_state == DB_UNCACHED ||
872 db->db_state == DB_NOFILL ||
873 db->db_state == DB_EVICTING) {
874 ASSERT(db->db.db_data == NULL);
875 mutex_exit(&db->db_mtx);
878 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
879 /* will be handled in dbuf_read_done or dbuf_rele */
880 db->db_freed_in_flight = TRUE;
881 mutex_exit(&db->db_mtx);
884 if (refcount_count(&db->db_holds) == 0) {
889 /* The dbuf is referenced */
891 if (db->db_last_dirty != NULL) {
892 dbuf_dirty_record_t *dr = db->db_last_dirty;
894 if (dr->dr_txg == txg) {
896 * This buffer is "in-use", re-adjust the file
897 * size to reflect that this buffer may
898 * contain new data when we sync.
900 if (db->db_blkid != DMU_SPILL_BLKID &&
901 db->db_blkid > dn->dn_maxblkid)
902 dn->dn_maxblkid = db->db_blkid;
906 * This dbuf is not dirty in the open context.
907 * Either uncache it (if its not referenced in
908 * the open context) or reset its contents to
911 dbuf_fix_old_data(db, txg);
914 /* clear the contents if its cached */
915 if (db->db_state == DB_CACHED) {
916 ASSERT(db->db.db_data != NULL);
917 arc_release(db->db_buf, db);
918 bzero(db->db.db_data, db->db.db_size);
919 arc_buf_freeze(db->db_buf);
922 mutex_exit(&db->db_mtx);
924 mutex_exit(&dn->dn_dbufs_mtx);
928 dbuf_block_freeable(dmu_buf_impl_t *db)
930 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
931 uint64_t birth_txg = 0;
934 * We don't need any locking to protect db_blkptr:
935 * If it's syncing, then db_last_dirty will be set
936 * so we'll ignore db_blkptr.
938 ASSERT(MUTEX_HELD(&db->db_mtx));
939 if (db->db_last_dirty)
940 birth_txg = db->db_last_dirty->dr_txg;
941 else if (db->db_blkptr)
942 birth_txg = db->db_blkptr->blk_birth;
945 * If we don't exist or are in a snapshot, we can't be freed.
946 * Don't pass the bp to dsl_dataset_block_freeable() since we
947 * are holding the db_mtx lock and might deadlock if we are
948 * prefetching a dedup-ed block.
951 return (ds == NULL ||
952 dsl_dataset_block_freeable(ds, NULL, birth_txg));
958 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
960 arc_buf_t *buf, *obuf;
961 int osize = db->db.db_size;
962 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
965 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
970 /* XXX does *this* func really need the lock? */
971 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
974 * This call to dbuf_will_dirty() with the dn_struct_rwlock held
975 * is OK, because there can be no other references to the db
976 * when we are changing its size, so no concurrent DB_FILL can
980 * XXX we should be doing a dbuf_read, checking the return
981 * value and returning that up to our callers
983 dbuf_will_dirty(db, tx);
985 /* create the data buffer for the new block */
986 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type);
988 /* copy old block data to the new block */
990 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
991 /* zero the remainder */
993 bzero((uint8_t *)buf->b_data + osize, size - osize);
995 mutex_enter(&db->db_mtx);
996 dbuf_set_data(db, buf);
997 VERIFY(arc_buf_remove_ref(obuf, db) == 1);
998 db->db.db_size = size;
1000 if (db->db_level == 0) {
1001 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
1002 db->db_last_dirty->dt.dl.dr_data = buf;
1004 mutex_exit(&db->db_mtx);
1006 dnode_willuse_space(dn, size-osize, tx);
1011 dbuf_release_bp(dmu_buf_impl_t *db)
1016 DB_GET_OBJSET(&os, db);
1017 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
1018 ASSERT(arc_released(os->os_phys_buf) ||
1019 list_link_active(&os->os_dsl_dataset->ds_synced_link));
1020 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf));
1022 zb.zb_objset = os->os_dsl_dataset ?
1023 os->os_dsl_dataset->ds_object : 0;
1024 zb.zb_object = db->db.db_object;
1025 zb.zb_level = db->db_level;
1026 zb.zb_blkid = db->db_blkid;
1027 (void) arc_release_bp(db->db_buf, db,
1028 db->db_blkptr, os->os_spa, &zb);
1031 dbuf_dirty_record_t *
1032 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1036 dbuf_dirty_record_t **drp, *dr;
1037 int drop_struct_lock = FALSE;
1038 boolean_t do_free_accounting = B_FALSE;
1039 int txgoff = tx->tx_txg & TXG_MASK;
1041 ASSERT(tx->tx_txg != 0);
1042 ASSERT(!refcount_is_zero(&db->db_holds));
1043 DMU_TX_DIRTY_BUF(tx, db);
1048 * Shouldn't dirty a regular buffer in syncing context. Private
1049 * objects may be dirtied in syncing context, but only if they
1050 * were already pre-dirtied in open context.
1052 ASSERT(!dmu_tx_is_syncing(tx) ||
1053 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
1054 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1055 dn->dn_objset->os_dsl_dataset == NULL);
1057 * We make this assert for private objects as well, but after we
1058 * check if we're already dirty. They are allowed to re-dirty
1059 * in syncing context.
1061 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1062 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1063 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1065 mutex_enter(&db->db_mtx);
1067 * XXX make this true for indirects too? The problem is that
1068 * transactions created with dmu_tx_create_assigned() from
1069 * syncing context don't bother holding ahead.
1071 ASSERT(db->db_level != 0 ||
1072 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
1073 db->db_state == DB_NOFILL);
1075 mutex_enter(&dn->dn_mtx);
1077 * Don't set dirtyctx to SYNC if we're just modifying this as we
1078 * initialize the objset.
1080 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
1081 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
1083 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
1084 ASSERT(dn->dn_dirtyctx_firstset == NULL);
1085 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
1087 mutex_exit(&dn->dn_mtx);
1089 if (db->db_blkid == DMU_SPILL_BLKID)
1090 dn->dn_have_spill = B_TRUE;
1093 * If this buffer is already dirty, we're done.
1095 drp = &db->db_last_dirty;
1096 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
1097 db->db.db_object == DMU_META_DNODE_OBJECT);
1098 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
1100 if (dr && dr->dr_txg == tx->tx_txg) {
1103 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
1105 * If this buffer has already been written out,
1106 * we now need to reset its state.
1108 dbuf_unoverride(dr);
1109 if (db->db.db_object != DMU_META_DNODE_OBJECT &&
1110 db->db_state != DB_NOFILL)
1111 arc_buf_thaw(db->db_buf);
1113 mutex_exit(&db->db_mtx);
1118 * Only valid if not already dirty.
1120 ASSERT(dn->dn_object == 0 ||
1121 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1122 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1124 ASSERT3U(dn->dn_nlevels, >, db->db_level);
1125 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
1126 dn->dn_phys->dn_nlevels > db->db_level ||
1127 dn->dn_next_nlevels[txgoff] > db->db_level ||
1128 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
1129 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
1132 * We should only be dirtying in syncing context if it's the
1133 * mos or we're initializing the os or it's a special object.
1134 * However, we are allowed to dirty in syncing context provided
1135 * we already dirtied it in open context. Hence we must make
1136 * this assertion only if we're not already dirty.
1139 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1140 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
1141 ASSERT(db->db.db_size != 0);
1143 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1145 if (db->db_blkid != DMU_BONUS_BLKID) {
1147 * Update the accounting.
1148 * Note: we delay "free accounting" until after we drop
1149 * the db_mtx. This keeps us from grabbing other locks
1150 * (and possibly deadlocking) in bp_get_dsize() while
1151 * also holding the db_mtx.
1153 dnode_willuse_space(dn, db->db.db_size, tx);
1154 do_free_accounting = dbuf_block_freeable(db);
1158 * If this buffer is dirty in an old transaction group we need
1159 * to make a copy of it so that the changes we make in this
1160 * transaction group won't leak out when we sync the older txg.
1162 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP);
1163 list_link_init(&dr->dr_dirty_node);
1164 if (db->db_level == 0) {
1165 void *data_old = db->db_buf;
1167 if (db->db_state != DB_NOFILL) {
1168 if (db->db_blkid == DMU_BONUS_BLKID) {
1169 dbuf_fix_old_data(db, tx->tx_txg);
1170 data_old = db->db.db_data;
1171 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1173 * Release the data buffer from the cache so
1174 * that we can modify it without impacting
1175 * possible other users of this cached data
1176 * block. Note that indirect blocks and
1177 * private objects are not released until the
1178 * syncing state (since they are only modified
1181 arc_release(db->db_buf, db);
1182 dbuf_fix_old_data(db, tx->tx_txg);
1183 data_old = db->db_buf;
1185 ASSERT(data_old != NULL);
1187 dr->dt.dl.dr_data = data_old;
1189 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1190 list_create(&dr->dt.di.dr_children,
1191 sizeof (dbuf_dirty_record_t),
1192 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1195 dr->dr_txg = tx->tx_txg;
1200 * We could have been freed_in_flight between the dbuf_noread
1201 * and dbuf_dirty. We win, as though the dbuf_noread() had
1202 * happened after the free.
1204 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1205 db->db_blkid != DMU_SPILL_BLKID) {
1206 mutex_enter(&dn->dn_mtx);
1207 dnode_clear_range(dn, db->db_blkid, 1, tx);
1208 mutex_exit(&dn->dn_mtx);
1209 db->db_freed_in_flight = FALSE;
1213 * This buffer is now part of this txg
1215 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1216 db->db_dirtycnt += 1;
1217 ASSERT3U(db->db_dirtycnt, <=, 3);
1219 mutex_exit(&db->db_mtx);
1221 if (db->db_blkid == DMU_BONUS_BLKID ||
1222 db->db_blkid == DMU_SPILL_BLKID) {
1223 mutex_enter(&dn->dn_mtx);
1224 ASSERT(!list_link_active(&dr->dr_dirty_node));
1225 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1226 mutex_exit(&dn->dn_mtx);
1227 dnode_setdirty(dn, tx);
1230 } else if (do_free_accounting) {
1231 blkptr_t *bp = db->db_blkptr;
1232 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1233 bp_get_dsize(os->os_spa, bp) : db->db.db_size;
1235 * This is only a guess -- if the dbuf is dirty
1236 * in a previous txg, we don't know how much
1237 * space it will use on disk yet. We should
1238 * really have the struct_rwlock to access
1239 * db_blkptr, but since this is just a guess,
1240 * it's OK if we get an odd answer.
1242 ddt_prefetch(os->os_spa, bp);
1243 dnode_willuse_space(dn, -willfree, tx);
1246 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1247 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1248 drop_struct_lock = TRUE;
1251 if (db->db_level == 0) {
1252 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1253 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1256 if (db->db_level+1 < dn->dn_nlevels) {
1257 dmu_buf_impl_t *parent = db->db_parent;
1258 dbuf_dirty_record_t *di;
1259 int parent_held = FALSE;
1261 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1262 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1264 parent = dbuf_hold_level(dn, db->db_level+1,
1265 db->db_blkid >> epbs, FTAG);
1266 ASSERT(parent != NULL);
1269 if (drop_struct_lock)
1270 rw_exit(&dn->dn_struct_rwlock);
1271 ASSERT3U(db->db_level+1, ==, parent->db_level);
1272 di = dbuf_dirty(parent, tx);
1274 dbuf_rele(parent, FTAG);
1276 mutex_enter(&db->db_mtx);
1277 /* possible race with dbuf_undirty() */
1278 if (db->db_last_dirty == dr ||
1279 dn->dn_object == DMU_META_DNODE_OBJECT) {
1280 mutex_enter(&di->dt.di.dr_mtx);
1281 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1282 ASSERT(!list_link_active(&dr->dr_dirty_node));
1283 list_insert_tail(&di->dt.di.dr_children, dr);
1284 mutex_exit(&di->dt.di.dr_mtx);
1287 mutex_exit(&db->db_mtx);
1289 ASSERT(db->db_level+1 == dn->dn_nlevels);
1290 ASSERT(db->db_blkid < dn->dn_nblkptr);
1291 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf);
1292 mutex_enter(&dn->dn_mtx);
1293 ASSERT(!list_link_active(&dr->dr_dirty_node));
1294 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1295 mutex_exit(&dn->dn_mtx);
1296 if (drop_struct_lock)
1297 rw_exit(&dn->dn_struct_rwlock);
1300 dnode_setdirty(dn, tx);
1306 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1309 uint64_t txg = tx->tx_txg;
1310 dbuf_dirty_record_t *dr, **drp;
1313 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1315 mutex_enter(&db->db_mtx);
1317 * If this buffer is not dirty, we're done.
1319 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1320 if (dr->dr_txg <= txg)
1322 if (dr == NULL || dr->dr_txg < txg) {
1323 mutex_exit(&db->db_mtx);
1326 ASSERT(dr->dr_txg == txg);
1327 ASSERT(dr->dr_dbuf == db);
1333 * If this buffer is currently held, we cannot undirty
1334 * it, since one of the current holders may be in the
1335 * middle of an update. Note that users of dbuf_undirty()
1336 * should not place a hold on the dbuf before the call.
1338 if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
1339 mutex_exit(&db->db_mtx);
1340 /* Make sure we don't toss this buffer at sync phase */
1341 mutex_enter(&dn->dn_mtx);
1342 dnode_clear_range(dn, db->db_blkid, 1, tx);
1343 mutex_exit(&dn->dn_mtx);
1348 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1350 ASSERT(db->db.db_size != 0);
1352 /* XXX would be nice to fix up dn_towrite_space[] */
1356 if (dr->dr_parent) {
1357 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1358 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1359 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1360 } else if (db->db_level+1 == dn->dn_nlevels) {
1361 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
1362 mutex_enter(&dn->dn_mtx);
1363 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
1364 mutex_exit(&dn->dn_mtx);
1368 if (db->db_level == 0) {
1369 if (db->db_state != DB_NOFILL) {
1370 dbuf_unoverride(dr);
1372 ASSERT(db->db_buf != NULL);
1373 ASSERT(dr->dt.dl.dr_data != NULL);
1374 if (dr->dt.dl.dr_data != db->db_buf)
1375 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
1379 ASSERT(db->db_buf != NULL);
1380 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
1381 mutex_destroy(&dr->dt.di.dr_mtx);
1382 list_destroy(&dr->dt.di.dr_children);
1384 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1386 ASSERT(db->db_dirtycnt > 0);
1387 db->db_dirtycnt -= 1;
1389 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1390 arc_buf_t *buf = db->db_buf;
1392 ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
1393 dbuf_set_data(db, NULL);
1394 VERIFY(arc_buf_remove_ref(buf, db) == 1);
1399 mutex_exit(&db->db_mtx);
1403 #pragma weak dmu_buf_will_dirty = dbuf_will_dirty
1405 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1407 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1409 ASSERT(tx->tx_txg != 0);
1410 ASSERT(!refcount_is_zero(&db->db_holds));
1413 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
1414 rf |= DB_RF_HAVESTRUCT;
1416 (void) dbuf_read(db, NULL, rf);
1417 (void) dbuf_dirty(db, tx);
1421 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1423 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1425 db->db_state = DB_NOFILL;
1427 dmu_buf_will_fill(db_fake, tx);
1431 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1433 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1435 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1436 ASSERT(tx->tx_txg != 0);
1437 ASSERT(db->db_level == 0);
1438 ASSERT(!refcount_is_zero(&db->db_holds));
1440 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1441 dmu_tx_private_ok(tx));
1444 (void) dbuf_dirty(db, tx);
1447 #pragma weak dmu_buf_fill_done = dbuf_fill_done
1450 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1452 mutex_enter(&db->db_mtx);
1455 if (db->db_state == DB_FILL) {
1456 if (db->db_level == 0 && db->db_freed_in_flight) {
1457 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1458 /* we were freed while filling */
1459 /* XXX dbuf_undirty? */
1460 bzero(db->db.db_data, db->db.db_size);
1461 db->db_freed_in_flight = FALSE;
1463 db->db_state = DB_CACHED;
1464 cv_broadcast(&db->db_changed);
1466 mutex_exit(&db->db_mtx);
1470 * Directly assign a provided arc buf to a given dbuf if it's not referenced
1471 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
1474 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
1476 ASSERT(!refcount_is_zero(&db->db_holds));
1477 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1478 ASSERT(db->db_level == 0);
1479 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
1480 ASSERT(buf != NULL);
1481 ASSERT(arc_buf_size(buf) == db->db.db_size);
1482 ASSERT(tx->tx_txg != 0);
1484 arc_return_buf(buf, db);
1485 ASSERT(arc_released(buf));
1487 mutex_enter(&db->db_mtx);
1489 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1490 cv_wait(&db->db_changed, &db->db_mtx);
1492 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
1494 if (db->db_state == DB_CACHED &&
1495 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
1496 mutex_exit(&db->db_mtx);
1497 (void) dbuf_dirty(db, tx);
1498 bcopy(buf->b_data, db->db.db_data, db->db.db_size);
1499 VERIFY(arc_buf_remove_ref(buf, db) == 1);
1500 xuio_stat_wbuf_copied();
1504 xuio_stat_wbuf_nocopy();
1505 if (db->db_state == DB_CACHED) {
1506 dbuf_dirty_record_t *dr = db->db_last_dirty;
1508 ASSERT(db->db_buf != NULL);
1509 if (dr != NULL && dr->dr_txg == tx->tx_txg) {
1510 ASSERT(dr->dt.dl.dr_data == db->db_buf);
1511 if (!arc_released(db->db_buf)) {
1512 ASSERT(dr->dt.dl.dr_override_state ==
1514 arc_release(db->db_buf, db);
1516 dr->dt.dl.dr_data = buf;
1517 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
1518 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
1519 arc_release(db->db_buf, db);
1520 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
1524 ASSERT(db->db_buf == NULL);
1525 dbuf_set_data(db, buf);
1526 db->db_state = DB_FILL;
1527 mutex_exit(&db->db_mtx);
1528 (void) dbuf_dirty(db, tx);
1529 dbuf_fill_done(db, tx);
1533 * "Clear" the contents of this dbuf. This will mark the dbuf
1534 * EVICTING and clear *most* of its references. Unfortunetely,
1535 * when we are not holding the dn_dbufs_mtx, we can't clear the
1536 * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
1537 * in this case. For callers from the DMU we will usually see:
1538 * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy()
1539 * For the arc callback, we will usually see:
1540 * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
1541 * Sometimes, though, we will get a mix of these two:
1542 * DMU: dbuf_clear()->arc_buf_evict()
1543 * ARC: dbuf_do_evict()->dbuf_destroy()
1546 dbuf_clear(dmu_buf_impl_t *db)
1549 dmu_buf_impl_t *parent = db->db_parent;
1550 dmu_buf_impl_t *dndb;
1551 int dbuf_gone = FALSE;
1553 ASSERT(MUTEX_HELD(&db->db_mtx));
1554 ASSERT(refcount_is_zero(&db->db_holds));
1556 dbuf_evict_user(db);
1558 if (db->db_state == DB_CACHED) {
1559 ASSERT(db->db.db_data != NULL);
1560 if (db->db_blkid == DMU_BONUS_BLKID) {
1561 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1562 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1564 db->db.db_data = NULL;
1565 db->db_state = DB_UNCACHED;
1568 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
1569 ASSERT(db->db_data_pending == NULL);
1571 db->db_state = DB_EVICTING;
1572 db->db_blkptr = NULL;
1577 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1578 list_remove(&dn->dn_dbufs, db);
1579 (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1583 * Decrementing the dbuf count means that the hold corresponding
1584 * to the removed dbuf is no longer discounted in dnode_move(),
1585 * so the dnode cannot be moved until after we release the hold.
1586 * The membar_producer() ensures visibility of the decremented
1587 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually
1591 db->db_dnode_handle = NULL;
1597 dbuf_gone = arc_buf_evict(db->db_buf);
1600 mutex_exit(&db->db_mtx);
1603 * If this dbuf is referenced from an indirect dbuf,
1604 * decrement the ref count on the indirect dbuf.
1606 if (parent && parent != dndb)
1607 dbuf_rele(parent, db);
1611 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1612 dmu_buf_impl_t **parentp, blkptr_t **bpp, struct dbuf_hold_impl_data *dh)
1619 ASSERT(blkid != DMU_BONUS_BLKID);
1621 if (blkid == DMU_SPILL_BLKID) {
1622 mutex_enter(&dn->dn_mtx);
1623 if (dn->dn_have_spill &&
1624 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
1625 *bpp = &dn->dn_phys->dn_spill;
1628 dbuf_add_ref(dn->dn_dbuf, NULL);
1629 *parentp = dn->dn_dbuf;
1630 mutex_exit(&dn->dn_mtx);
1634 if (dn->dn_phys->dn_nlevels == 0)
1637 nlevels = dn->dn_phys->dn_nlevels;
1639 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1641 ASSERT3U(level * epbs, <, 64);
1642 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1643 if (level >= nlevels ||
1644 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
1645 /* the buffer has no parent yet */
1647 } else if (level < nlevels-1) {
1648 /* this block is referenced from an indirect block */
1651 err = dbuf_hold_impl(dn, level+1, blkid >> epbs,
1652 fail_sparse, NULL, parentp);
1655 __dbuf_hold_impl_init(dh + 1, dn, dh->dh_level + 1,
1656 blkid >> epbs, fail_sparse, NULL,
1657 parentp, dh->dh_depth + 1);
1658 err = __dbuf_hold_impl(dh + 1);
1662 err = dbuf_read(*parentp, NULL,
1663 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1665 dbuf_rele(*parentp, NULL);
1669 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1670 (blkid & ((1ULL << epbs) - 1));
1673 /* the block is referenced from the dnode */
1674 ASSERT3U(level, ==, nlevels-1);
1675 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1676 blkid < dn->dn_phys->dn_nblkptr);
1678 dbuf_add_ref(dn->dn_dbuf, NULL);
1679 *parentp = dn->dn_dbuf;
1681 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1686 static dmu_buf_impl_t *
1687 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1688 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1690 objset_t *os = dn->dn_objset;
1691 dmu_buf_impl_t *db, *odb;
1693 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1694 ASSERT(dn->dn_type != DMU_OT_NONE);
1696 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP);
1699 db->db.db_object = dn->dn_object;
1700 db->db_level = level;
1701 db->db_blkid = blkid;
1702 db->db_last_dirty = NULL;
1703 db->db_dirtycnt = 0;
1704 db->db_dnode_handle = dn->dn_handle;
1705 db->db_parent = parent;
1706 db->db_blkptr = blkptr;
1708 db->db_user_ptr = NULL;
1709 db->db_user_data_ptr_ptr = NULL;
1710 db->db_evict_func = NULL;
1711 db->db_immediate_evict = 0;
1712 db->db_freed_in_flight = 0;
1714 if (blkid == DMU_BONUS_BLKID) {
1715 ASSERT3P(parent, ==, dn->dn_dbuf);
1716 db->db.db_size = DN_MAX_BONUSLEN -
1717 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1718 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1719 db->db.db_offset = DMU_BONUS_BLKID;
1720 db->db_state = DB_UNCACHED;
1721 /* the bonus dbuf is not placed in the hash table */
1722 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1724 } else if (blkid == DMU_SPILL_BLKID) {
1725 db->db.db_size = (blkptr != NULL) ?
1726 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE;
1727 db->db.db_offset = 0;
1730 db->db_level ? 1<<dn->dn_indblkshift : dn->dn_datablksz;
1731 db->db.db_size = blocksize;
1732 db->db.db_offset = db->db_blkid * blocksize;
1736 * Hold the dn_dbufs_mtx while we get the new dbuf
1737 * in the hash table *and* added to the dbufs list.
1738 * This prevents a possible deadlock with someone
1739 * trying to look up this dbuf before its added to the
1742 mutex_enter(&dn->dn_dbufs_mtx);
1743 db->db_state = DB_EVICTING;
1744 if ((odb = dbuf_hash_insert(db)) != NULL) {
1745 /* someone else inserted it first */
1746 kmem_cache_free(dbuf_cache, db);
1747 mutex_exit(&dn->dn_dbufs_mtx);
1750 list_insert_head(&dn->dn_dbufs, db);
1751 db->db_state = DB_UNCACHED;
1752 mutex_exit(&dn->dn_dbufs_mtx);
1753 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1755 if (parent && parent != dn->dn_dbuf)
1756 dbuf_add_ref(parent, db);
1758 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1759 refcount_count(&dn->dn_holds) > 0);
1760 (void) refcount_add(&dn->dn_holds, db);
1761 (void) atomic_inc_32_nv(&dn->dn_dbufs_count);
1763 dprintf_dbuf(db, "db=%p\n", db);
1769 dbuf_do_evict(void *private)
1771 arc_buf_t *buf = private;
1772 dmu_buf_impl_t *db = buf->b_private;
1774 if (!MUTEX_HELD(&db->db_mtx))
1775 mutex_enter(&db->db_mtx);
1777 ASSERT(refcount_is_zero(&db->db_holds));
1779 if (db->db_state != DB_EVICTING) {
1780 ASSERT(db->db_state == DB_CACHED);
1785 mutex_exit(&db->db_mtx);
1792 dbuf_destroy(dmu_buf_impl_t *db)
1794 ASSERT(refcount_is_zero(&db->db_holds));
1796 if (db->db_blkid != DMU_BONUS_BLKID) {
1798 * If this dbuf is still on the dn_dbufs list,
1799 * remove it from that list.
1801 if (db->db_dnode_handle != NULL) {
1806 mutex_enter(&dn->dn_dbufs_mtx);
1807 list_remove(&dn->dn_dbufs, db);
1808 (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1809 mutex_exit(&dn->dn_dbufs_mtx);
1812 * Decrementing the dbuf count means that the hold
1813 * corresponding to the removed dbuf is no longer
1814 * discounted in dnode_move(), so the dnode cannot be
1815 * moved until after we release the hold.
1818 db->db_dnode_handle = NULL;
1820 dbuf_hash_remove(db);
1822 db->db_parent = NULL;
1825 ASSERT(!list_link_active(&db->db_link));
1826 ASSERT(db->db.db_data == NULL);
1827 ASSERT(db->db_hash_next == NULL);
1828 ASSERT(db->db_blkptr == NULL);
1829 ASSERT(db->db_data_pending == NULL);
1831 kmem_cache_free(dbuf_cache, db);
1832 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1836 dbuf_prefetch(dnode_t *dn, uint64_t blkid)
1838 dmu_buf_impl_t *db = NULL;
1839 blkptr_t *bp = NULL;
1841 ASSERT(blkid != DMU_BONUS_BLKID);
1842 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1844 if (dnode_block_freed(dn, blkid))
1847 /* dbuf_find() returns with db_mtx held */
1848 if ((db = dbuf_find(dn, 0, blkid))) {
1850 * This dbuf is already in the cache. We assume that
1851 * it is already CACHED, or else about to be either
1854 mutex_exit(&db->db_mtx);
1858 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp, NULL) == 0) {
1859 if (bp && !BP_IS_HOLE(bp)) {
1860 int priority = dn->dn_type == DMU_OT_DDT_ZAP ?
1861 ZIO_PRIORITY_DDT_PREFETCH : ZIO_PRIORITY_ASYNC_READ;
1863 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
1864 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
1867 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1868 dn->dn_object, 0, blkid);
1873 pbuf = dn->dn_objset->os_phys_buf;
1875 (void) dsl_read(NULL, dn->dn_objset->os_spa,
1876 bp, pbuf, NULL, NULL, priority,
1877 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1881 dbuf_rele(db, NULL);
1885 #define DBUF_HOLD_IMPL_MAX_DEPTH 20
1888 * Returns with db_holds incremented, and db_mtx not held.
1889 * Note: dn_struct_rwlock must be held.
1892 __dbuf_hold_impl(struct dbuf_hold_impl_data *dh)
1894 ASSERT3S(dh->dh_depth, <, DBUF_HOLD_IMPL_MAX_DEPTH);
1895 dh->dh_parent = NULL;
1897 ASSERT(dh->dh_blkid != DMU_BONUS_BLKID);
1898 ASSERT(RW_LOCK_HELD(&dh->dh_dn->dn_struct_rwlock));
1899 ASSERT3U(dh->dh_dn->dn_nlevels, >, dh->dh_level);
1901 *(dh->dh_dbp) = NULL;
1903 /* dbuf_find() returns with db_mtx held */
1904 dh->dh_db = dbuf_find(dh->dh_dn, dh->dh_level, dh->dh_blkid);
1906 if (dh->dh_db == NULL) {
1909 ASSERT3P(dh->dh_parent, ==, NULL);
1910 dh->dh_err = dbuf_findbp(dh->dh_dn, dh->dh_level, dh->dh_blkid,
1911 dh->dh_fail_sparse, &dh->dh_parent,
1913 if (dh->dh_fail_sparse) {
1914 if (dh->dh_err == 0 && dh->dh_bp && BP_IS_HOLE(dh->dh_bp))
1915 dh->dh_err = ENOENT;
1918 dbuf_rele(dh->dh_parent, NULL);
1919 return (dh->dh_err);
1922 if (dh->dh_err && dh->dh_err != ENOENT)
1923 return (dh->dh_err);
1924 dh->dh_db = dbuf_create(dh->dh_dn, dh->dh_level, dh->dh_blkid,
1925 dh->dh_parent, dh->dh_bp);
1928 if (dh->dh_db->db_buf && refcount_is_zero(&dh->dh_db->db_holds)) {
1929 arc_buf_add_ref(dh->dh_db->db_buf, dh->dh_db);
1930 if (dh->dh_db->db_buf->b_data == NULL) {
1931 dbuf_clear(dh->dh_db);
1932 if (dh->dh_parent) {
1933 dbuf_rele(dh->dh_parent, NULL);
1934 dh->dh_parent = NULL;
1938 ASSERT3P(dh->dh_db->db.db_data, ==, dh->dh_db->db_buf->b_data);
1941 ASSERT(dh->dh_db->db_buf == NULL || arc_referenced(dh->dh_db->db_buf));
1944 * If this buffer is currently syncing out, and we are are
1945 * still referencing it from db_data, we need to make a copy
1946 * of it in case we decide we want to dirty it again in this txg.
1948 if (dh->dh_db->db_level == 0 &&
1949 dh->dh_db->db_blkid != DMU_BONUS_BLKID &&
1950 dh->dh_dn->dn_object != DMU_META_DNODE_OBJECT &&
1951 dh->dh_db->db_state == DB_CACHED && dh->dh_db->db_data_pending) {
1952 dh->dh_dr = dh->dh_db->db_data_pending;
1954 if (dh->dh_dr->dt.dl.dr_data == dh->dh_db->db_buf) {
1955 dh->dh_type = DBUF_GET_BUFC_TYPE(dh->dh_db);
1957 dbuf_set_data(dh->dh_db,
1958 arc_buf_alloc(dh->dh_dn->dn_objset->os_spa,
1959 dh->dh_db->db.db_size, dh->dh_db, dh->dh_type));
1960 bcopy(dh->dh_dr->dt.dl.dr_data->b_data,
1961 dh->dh_db->db.db_data, dh->dh_db->db.db_size);
1965 (void) refcount_add(&dh->dh_db->db_holds, dh->dh_tag);
1966 dbuf_update_data(dh->dh_db);
1967 DBUF_VERIFY(dh->dh_db);
1968 mutex_exit(&dh->dh_db->db_mtx);
1970 /* NOTE: we can't rele the parent until after we drop the db_mtx */
1972 dbuf_rele(dh->dh_parent, NULL);
1974 ASSERT3P(DB_DNODE(dh->dh_db), ==, dh->dh_dn);
1975 ASSERT3U(dh->dh_db->db_blkid, ==, dh->dh_blkid);
1976 ASSERT3U(dh->dh_db->db_level, ==, dh->dh_level);
1977 *(dh->dh_dbp) = dh->dh_db;
1983 * The following code preserves the recursive function dbuf_hold_impl()
1984 * but moves the local variables AND function arguments to the heap to
1985 * minimize the stack frame size. Enough space is initially allocated
1986 * on the stack for 20 levels of recursion.
1989 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
1990 void *tag, dmu_buf_impl_t **dbp)
1992 struct dbuf_hold_impl_data *dh;
1995 dh = kmem_zalloc(sizeof(struct dbuf_hold_impl_data) *
1996 DBUF_HOLD_IMPL_MAX_DEPTH, KM_SLEEP);
1997 __dbuf_hold_impl_init(dh, dn, level, blkid, fail_sparse, tag, dbp, 0);
1999 error = __dbuf_hold_impl(dh);
2001 kmem_free(dh, sizeof(struct dbuf_hold_impl_data) *
2002 DBUF_HOLD_IMPL_MAX_DEPTH);
2008 __dbuf_hold_impl_init(struct dbuf_hold_impl_data *dh,
2009 dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
2010 void *tag, dmu_buf_impl_t **dbp, int depth)
2013 dh->dh_level = level;
2014 dh->dh_blkid = blkid;
2015 dh->dh_fail_sparse = fail_sparse;
2018 dh->dh_depth = depth;
2022 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
2025 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
2026 return (err ? NULL : db);
2030 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
2033 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
2034 return (err ? NULL : db);
2038 dbuf_create_bonus(dnode_t *dn)
2040 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
2042 ASSERT(dn->dn_bonus == NULL);
2043 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL);
2047 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx)
2049 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2052 if (db->db_blkid != DMU_SPILL_BLKID)
2055 blksz = SPA_MINBLOCKSIZE;
2056 if (blksz > SPA_MAXBLOCKSIZE)
2057 blksz = SPA_MAXBLOCKSIZE;
2059 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE);
2063 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
2064 dbuf_new_size(db, blksz, tx);
2065 rw_exit(&dn->dn_struct_rwlock);
2072 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx)
2074 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx);
2077 #pragma weak dmu_buf_add_ref = dbuf_add_ref
2079 dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
2081 VERIFY(refcount_add(&db->db_holds, tag) > 1);
2085 * If you call dbuf_rele() you had better not be referencing the dnode handle
2086 * unless you have some other direct or indirect hold on the dnode. (An indirect
2087 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.)
2088 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the
2089 * dnode's parent dbuf evicting its dnode handles.
2091 #pragma weak dmu_buf_rele = dbuf_rele
2093 dbuf_rele(dmu_buf_impl_t *db, void *tag)
2095 mutex_enter(&db->db_mtx);
2096 dbuf_rele_and_unlock(db, tag);
2100 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
2101 * db_dirtycnt and db_holds to be updated atomically.
2104 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
2108 ASSERT(MUTEX_HELD(&db->db_mtx));
2112 * Remove the reference to the dbuf before removing its hold on the
2113 * dnode so we can guarantee in dnode_move() that a referenced bonus
2114 * buffer has a corresponding dnode hold.
2116 holds = refcount_remove(&db->db_holds, tag);
2120 * We can't freeze indirects if there is a possibility that they
2121 * may be modified in the current syncing context.
2123 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
2124 arc_buf_freeze(db->db_buf);
2126 if (holds == db->db_dirtycnt &&
2127 db->db_level == 0 && db->db_immediate_evict)
2128 dbuf_evict_user(db);
2131 if (db->db_blkid == DMU_BONUS_BLKID) {
2132 mutex_exit(&db->db_mtx);
2135 * If the dnode moves here, we cannot cross this barrier
2136 * until the move completes.
2139 (void) atomic_dec_32_nv(&DB_DNODE(db)->dn_dbufs_count);
2142 * The bonus buffer's dnode hold is no longer discounted
2143 * in dnode_move(). The dnode cannot move until after
2146 dnode_rele(DB_DNODE(db), db);
2147 } else if (db->db_buf == NULL) {
2149 * This is a special case: we never associated this
2150 * dbuf with any data allocated from the ARC.
2152 ASSERT(db->db_state == DB_UNCACHED ||
2153 db->db_state == DB_NOFILL);
2155 } else if (arc_released(db->db_buf)) {
2156 arc_buf_t *buf = db->db_buf;
2158 * This dbuf has anonymous data associated with it.
2160 dbuf_set_data(db, NULL);
2161 VERIFY(arc_buf_remove_ref(buf, db) == 1);
2164 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 0);
2165 if (!DBUF_IS_CACHEABLE(db))
2168 mutex_exit(&db->db_mtx);
2171 mutex_exit(&db->db_mtx);
2175 #pragma weak dmu_buf_refcount = dbuf_refcount
2177 dbuf_refcount(dmu_buf_impl_t *db)
2179 return (refcount_count(&db->db_holds));
2183 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
2184 dmu_buf_evict_func_t *evict_func)
2186 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
2187 user_data_ptr_ptr, evict_func));
2191 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
2192 dmu_buf_evict_func_t *evict_func)
2194 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2196 db->db_immediate_evict = TRUE;
2197 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
2198 user_data_ptr_ptr, evict_func));
2202 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr,
2203 void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func)
2205 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2206 ASSERT(db->db_level == 0);
2208 ASSERT((user_ptr == NULL) == (evict_func == NULL));
2210 mutex_enter(&db->db_mtx);
2212 if (db->db_user_ptr == old_user_ptr) {
2213 db->db_user_ptr = user_ptr;
2214 db->db_user_data_ptr_ptr = user_data_ptr_ptr;
2215 db->db_evict_func = evict_func;
2217 dbuf_update_data(db);
2219 old_user_ptr = db->db_user_ptr;
2222 mutex_exit(&db->db_mtx);
2223 return (old_user_ptr);
2227 dmu_buf_get_user(dmu_buf_t *db_fake)
2229 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2230 ASSERT(!refcount_is_zero(&db->db_holds));
2232 return (db->db_user_ptr);
2236 dmu_buf_freeable(dmu_buf_t *dbuf)
2238 boolean_t res = B_FALSE;
2239 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
2242 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
2243 db->db_blkptr, db->db_blkptr->blk_birth);
2249 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
2251 /* ASSERT(dmu_tx_is_syncing(tx) */
2252 ASSERT(MUTEX_HELD(&db->db_mtx));
2254 if (db->db_blkptr != NULL)
2257 if (db->db_blkid == DMU_SPILL_BLKID) {
2258 db->db_blkptr = &dn->dn_phys->dn_spill;
2259 BP_ZERO(db->db_blkptr);
2262 if (db->db_level == dn->dn_phys->dn_nlevels-1) {
2264 * This buffer was allocated at a time when there was
2265 * no available blkptrs from the dnode, or it was
2266 * inappropriate to hook it in (i.e., nlevels mis-match).
2268 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr);
2269 ASSERT(db->db_parent == NULL);
2270 db->db_parent = dn->dn_dbuf;
2271 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid];
2274 dmu_buf_impl_t *parent = db->db_parent;
2275 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2277 ASSERT(dn->dn_phys->dn_nlevels > 1);
2278 if (parent == NULL) {
2279 mutex_exit(&db->db_mtx);
2280 rw_enter(&dn->dn_struct_rwlock, RW_READER);
2281 (void) dbuf_hold_impl(dn, db->db_level+1,
2282 db->db_blkid >> epbs, FALSE, db, &parent);
2283 rw_exit(&dn->dn_struct_rwlock);
2284 mutex_enter(&db->db_mtx);
2285 db->db_parent = parent;
2287 db->db_blkptr = (blkptr_t *)parent->db.db_data +
2288 (db->db_blkid & ((1ULL << epbs) - 1));
2294 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2296 dmu_buf_impl_t *db = dr->dr_dbuf;
2300 ASSERT(dmu_tx_is_syncing(tx));
2302 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2304 mutex_enter(&db->db_mtx);
2306 ASSERT(db->db_level > 0);
2309 if (db->db_buf == NULL) {
2310 mutex_exit(&db->db_mtx);
2311 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
2312 mutex_enter(&db->db_mtx);
2314 ASSERT3U(db->db_state, ==, DB_CACHED);
2315 ASSERT(db->db_buf != NULL);
2319 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2320 dbuf_check_blkptr(dn, db);
2323 db->db_data_pending = dr;
2325 mutex_exit(&db->db_mtx);
2326 dbuf_write(dr, db->db_buf, tx);
2329 mutex_enter(&dr->dt.di.dr_mtx);
2330 dbuf_sync_list(&dr->dt.di.dr_children, tx);
2331 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2332 mutex_exit(&dr->dt.di.dr_mtx);
2337 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2339 arc_buf_t **datap = &dr->dt.dl.dr_data;
2340 dmu_buf_impl_t *db = dr->dr_dbuf;
2343 uint64_t txg = tx->tx_txg;
2345 ASSERT(dmu_tx_is_syncing(tx));
2347 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2349 mutex_enter(&db->db_mtx);
2351 * To be synced, we must be dirtied. But we
2352 * might have been freed after the dirty.
2354 if (db->db_state == DB_UNCACHED) {
2355 /* This buffer has been freed since it was dirtied */
2356 ASSERT(db->db.db_data == NULL);
2357 } else if (db->db_state == DB_FILL) {
2358 /* This buffer was freed and is now being re-filled */
2359 ASSERT(db->db.db_data != dr->dt.dl.dr_data);
2361 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL);
2368 if (db->db_blkid == DMU_SPILL_BLKID) {
2369 mutex_enter(&dn->dn_mtx);
2370 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR;
2371 mutex_exit(&dn->dn_mtx);
2375 * If this is a bonus buffer, simply copy the bonus data into the
2376 * dnode. It will be written out when the dnode is synced (and it
2377 * will be synced, since it must have been dirty for dbuf_sync to
2380 if (db->db_blkid == DMU_BONUS_BLKID) {
2381 dbuf_dirty_record_t **drp;
2383 ASSERT(*datap != NULL);
2384 ASSERT3U(db->db_level, ==, 0);
2385 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
2386 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
2389 if (*datap != db->db.db_data) {
2390 zio_buf_free(*datap, DN_MAX_BONUSLEN);
2391 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
2393 db->db_data_pending = NULL;
2394 drp = &db->db_last_dirty;
2396 drp = &(*drp)->dr_next;
2397 ASSERT(dr->dr_next == NULL);
2398 ASSERT(dr->dr_dbuf == db);
2400 if (dr->dr_dbuf->db_level != 0) {
2401 mutex_destroy(&dr->dt.di.dr_mtx);
2402 list_destroy(&dr->dt.di.dr_children);
2404 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2405 ASSERT(db->db_dirtycnt > 0);
2406 db->db_dirtycnt -= 1;
2407 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2414 * This function may have dropped the db_mtx lock allowing a dmu_sync
2415 * operation to sneak in. As a result, we need to ensure that we
2416 * don't check the dr_override_state until we have returned from
2417 * dbuf_check_blkptr.
2419 dbuf_check_blkptr(dn, db);
2422 * If this buffer is in the middle of an immediate write,
2423 * wait for the synchronous IO to complete.
2425 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
2426 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
2427 cv_wait(&db->db_changed, &db->db_mtx);
2428 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
2431 if (db->db_state != DB_NOFILL &&
2432 dn->dn_object != DMU_META_DNODE_OBJECT &&
2433 refcount_count(&db->db_holds) > 1 &&
2434 dr->dt.dl.dr_override_state != DR_OVERRIDDEN &&
2435 *datap == db->db_buf) {
2437 * If this buffer is currently "in use" (i.e., there
2438 * are active holds and db_data still references it),
2439 * then make a copy before we start the write so that
2440 * any modifications from the open txg will not leak
2443 * NOTE: this copy does not need to be made for
2444 * objects only modified in the syncing context (e.g.
2445 * DNONE_DNODE blocks).
2447 int blksz = arc_buf_size(*datap);
2448 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2449 *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
2450 bcopy(db->db.db_data, (*datap)->b_data, blksz);
2452 db->db_data_pending = dr;
2454 mutex_exit(&db->db_mtx);
2456 dbuf_write(dr, *datap, tx);
2458 ASSERT(!list_link_active(&dr->dr_dirty_node));
2459 if (dn->dn_object == DMU_META_DNODE_OBJECT) {
2460 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr);
2464 * Although zio_nowait() does not "wait for an IO", it does
2465 * initiate the IO. If this is an empty write it seems plausible
2466 * that the IO could actually be completed before the nowait
2467 * returns. We need to DB_DNODE_EXIT() first in case
2468 * zio_nowait() invalidates the dbuf.
2471 zio_nowait(dr->dr_zio);
2476 dbuf_sync_list(list_t *list, dmu_tx_t *tx)
2478 dbuf_dirty_record_t *dr;
2480 while ((dr = list_head(list))) {
2481 if (dr->dr_zio != NULL) {
2483 * If we find an already initialized zio then we
2484 * are processing the meta-dnode, and we have finished.
2485 * The dbufs for all dnodes are put back on the list
2486 * during processing, so that we can zio_wait()
2487 * these IOs after initiating all child IOs.
2489 ASSERT3U(dr->dr_dbuf->db.db_object, ==,
2490 DMU_META_DNODE_OBJECT);
2493 list_remove(list, dr);
2494 if (dr->dr_dbuf->db_level > 0)
2495 dbuf_sync_indirect(dr, tx);
2497 dbuf_sync_leaf(dr, tx);
2503 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
2505 dmu_buf_impl_t *db = vdb;
2507 blkptr_t *bp = zio->io_bp;
2508 blkptr_t *bp_orig = &zio->io_bp_orig;
2509 spa_t *spa = zio->io_spa;
2514 ASSERT(db->db_blkptr == bp);
2518 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig);
2519 dnode_diduse_space(dn, delta - zio->io_prev_space_delta);
2520 zio->io_prev_space_delta = delta;
2522 if (BP_IS_HOLE(bp)) {
2523 ASSERT(bp->blk_fill == 0);
2528 ASSERT((db->db_blkid != DMU_SPILL_BLKID &&
2529 BP_GET_TYPE(bp) == dn->dn_type) ||
2530 (db->db_blkid == DMU_SPILL_BLKID &&
2531 BP_GET_TYPE(bp) == dn->dn_bonustype));
2532 ASSERT(BP_GET_LEVEL(bp) == db->db_level);
2534 mutex_enter(&db->db_mtx);
2537 if (db->db_blkid == DMU_SPILL_BLKID) {
2538 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2539 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2540 db->db_blkptr == &dn->dn_phys->dn_spill);
2544 if (db->db_level == 0) {
2545 mutex_enter(&dn->dn_mtx);
2546 if (db->db_blkid > dn->dn_phys->dn_maxblkid &&
2547 db->db_blkid != DMU_SPILL_BLKID)
2548 dn->dn_phys->dn_maxblkid = db->db_blkid;
2549 mutex_exit(&dn->dn_mtx);
2551 if (dn->dn_type == DMU_OT_DNODE) {
2552 dnode_phys_t *dnp = db->db.db_data;
2553 for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
2555 if (dnp->dn_type != DMU_OT_NONE)
2562 blkptr_t *ibp = db->db.db_data;
2563 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2564 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
2565 if (BP_IS_HOLE(ibp))
2567 fill += ibp->blk_fill;
2572 bp->blk_fill = fill;
2574 mutex_exit(&db->db_mtx);
2579 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
2581 dmu_buf_impl_t *db = vdb;
2582 blkptr_t *bp = zio->io_bp;
2583 blkptr_t *bp_orig = &zio->io_bp_orig;
2584 uint64_t txg = zio->io_txg;
2585 dbuf_dirty_record_t **drp, *dr;
2587 ASSERT3U(zio->io_error, ==, 0);
2588 ASSERT(db->db_blkptr == bp);
2590 if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
2591 ASSERT(BP_EQUAL(bp, bp_orig));
2597 DB_GET_OBJSET(&os, db);
2598 ds = os->os_dsl_dataset;
2601 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
2602 dsl_dataset_block_born(ds, bp, tx);
2605 mutex_enter(&db->db_mtx);
2609 drp = &db->db_last_dirty;
2610 while ((dr = *drp) != db->db_data_pending)
2612 ASSERT(!list_link_active(&dr->dr_dirty_node));
2613 ASSERT(dr->dr_txg == txg);
2614 ASSERT(dr->dr_dbuf == db);
2615 ASSERT(dr->dr_next == NULL);
2619 if (db->db_blkid == DMU_SPILL_BLKID) {
2624 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2625 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2626 db->db_blkptr == &dn->dn_phys->dn_spill);
2631 if (db->db_level == 0) {
2632 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
2633 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
2634 if (db->db_state != DB_NOFILL) {
2635 if (dr->dt.dl.dr_data != db->db_buf)
2636 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
2638 else if (!arc_released(db->db_buf))
2639 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2646 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2647 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2648 if (!BP_IS_HOLE(db->db_blkptr)) {
2649 ASSERTV(int epbs = dn->dn_phys->dn_indblkshift -
2651 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
2653 ASSERT3U(dn->dn_phys->dn_maxblkid
2654 >> (db->db_level * epbs), >=, db->db_blkid);
2655 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2658 mutex_destroy(&dr->dt.di.dr_mtx);
2659 list_destroy(&dr->dt.di.dr_children);
2661 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2663 cv_broadcast(&db->db_changed);
2664 ASSERT(db->db_dirtycnt > 0);
2665 db->db_dirtycnt -= 1;
2666 db->db_data_pending = NULL;
2667 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2671 dbuf_write_nofill_ready(zio_t *zio)
2673 dbuf_write_ready(zio, NULL, zio->io_private);
2677 dbuf_write_nofill_done(zio_t *zio)
2679 dbuf_write_done(zio, NULL, zio->io_private);
2683 dbuf_write_override_ready(zio_t *zio)
2685 dbuf_dirty_record_t *dr = zio->io_private;
2686 dmu_buf_impl_t *db = dr->dr_dbuf;
2688 dbuf_write_ready(zio, NULL, db);
2692 dbuf_write_override_done(zio_t *zio)
2694 dbuf_dirty_record_t *dr = zio->io_private;
2695 dmu_buf_impl_t *db = dr->dr_dbuf;
2696 blkptr_t *obp = &dr->dt.dl.dr_overridden_by;
2698 mutex_enter(&db->db_mtx);
2699 if (!BP_EQUAL(zio->io_bp, obp)) {
2700 if (!BP_IS_HOLE(obp))
2701 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp);
2702 arc_release(dr->dt.dl.dr_data, db);
2704 mutex_exit(&db->db_mtx);
2706 dbuf_write_done(zio, NULL, db);
2710 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
2712 dmu_buf_impl_t *db = dr->dr_dbuf;
2715 dmu_buf_impl_t *parent = db->db_parent;
2716 uint64_t txg = tx->tx_txg;
2726 if (db->db_state != DB_NOFILL) {
2727 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) {
2729 * Private object buffers are released here rather
2730 * than in dbuf_dirty() since they are only modified
2731 * in the syncing context and we don't want the
2732 * overhead of making multiple copies of the data.
2734 if (BP_IS_HOLE(db->db_blkptr)) {
2737 dbuf_release_bp(db);
2742 if (parent != dn->dn_dbuf) {
2743 ASSERT(parent && parent->db_data_pending);
2744 ASSERT(db->db_level == parent->db_level-1);
2745 ASSERT(arc_released(parent->db_buf));
2746 zio = parent->db_data_pending->dr_zio;
2748 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 &&
2749 db->db_blkid != DMU_SPILL_BLKID) ||
2750 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0));
2751 if (db->db_blkid != DMU_SPILL_BLKID)
2752 ASSERT3P(db->db_blkptr, ==,
2753 &dn->dn_phys->dn_blkptr[db->db_blkid]);
2757 ASSERT(db->db_level == 0 || data == db->db_buf);
2758 ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
2761 SET_BOOKMARK(&zb, os->os_dsl_dataset ?
2762 os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
2763 db->db.db_object, db->db_level, db->db_blkid);
2765 if (db->db_blkid == DMU_SPILL_BLKID)
2767 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0;
2769 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp);
2772 if (db->db_level == 0 && dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
2773 ASSERT(db->db_state != DB_NOFILL);
2774 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2775 db->db_blkptr, data->b_data, arc_buf_size(data), &zp,
2776 dbuf_write_override_ready, dbuf_write_override_done, dr,
2777 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2778 mutex_enter(&db->db_mtx);
2779 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
2780 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by,
2781 dr->dt.dl.dr_copies);
2782 mutex_exit(&db->db_mtx);
2783 } else if (db->db_state == DB_NOFILL) {
2784 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF);
2785 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2786 db->db_blkptr, NULL, db->db.db_size, &zp,
2787 dbuf_write_nofill_ready, dbuf_write_nofill_done, db,
2788 ZIO_PRIORITY_ASYNC_WRITE,
2789 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb);
2791 ASSERT(arc_released(data));
2792 dr->dr_zio = arc_write(zio, os->os_spa, txg,
2793 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), &zp,
2794 dbuf_write_ready, dbuf_write_done, db,
2795 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);