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) 2013 by Delphix. All rights reserved.
25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
26 * Copyright (c) 2013, Joyent, Inc. All rights reserved.
29 #include <sys/zfs_context.h>
31 #include <sys/dmu_send.h>
32 #include <sys/dmu_impl.h>
34 #include <sys/dmu_objset.h>
35 #include <sys/dsl_dataset.h>
36 #include <sys/dsl_dir.h>
37 #include <sys/dmu_tx.h>
40 #include <sys/dmu_zfetch.h>
42 #include <sys/sa_impl.h>
45 * Number of times that zfs_free_range() took the slow path while doing
46 * a zfs receive. A nonzero value indicates a potential performance problem.
48 uint64_t zfs_free_range_recv_miss;
50 static void dbuf_destroy(dmu_buf_impl_t *db);
51 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
52 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
55 * Global data structures and functions for the dbuf cache.
57 static kmem_cache_t *dbuf_cache;
61 dbuf_cons(void *vdb, void *unused, int kmflag)
63 dmu_buf_impl_t *db = vdb;
64 bzero(db, sizeof (dmu_buf_impl_t));
66 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
67 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
68 refcount_create(&db->db_holds);
74 dbuf_dest(void *vdb, void *unused)
76 dmu_buf_impl_t *db = vdb;
77 mutex_destroy(&db->db_mtx);
78 cv_destroy(&db->db_changed);
79 refcount_destroy(&db->db_holds);
83 * dbuf hash table routines
85 static dbuf_hash_table_t dbuf_hash_table;
87 static uint64_t dbuf_hash_count;
90 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
92 uintptr_t osv = (uintptr_t)os;
95 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
96 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
97 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
98 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
99 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
100 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
101 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
103 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
108 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
110 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
111 ((dbuf)->db.db_object == (obj) && \
112 (dbuf)->db_objset == (os) && \
113 (dbuf)->db_level == (level) && \
114 (dbuf)->db_blkid == (blkid))
117 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
119 dbuf_hash_table_t *h = &dbuf_hash_table;
120 objset_t *os = dn->dn_objset;
121 uint64_t obj = dn->dn_object;
122 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
123 uint64_t idx = hv & h->hash_table_mask;
126 mutex_enter(DBUF_HASH_MUTEX(h, idx));
127 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
128 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
129 mutex_enter(&db->db_mtx);
130 if (db->db_state != DB_EVICTING) {
131 mutex_exit(DBUF_HASH_MUTEX(h, idx));
134 mutex_exit(&db->db_mtx);
137 mutex_exit(DBUF_HASH_MUTEX(h, idx));
142 * Insert an entry into the hash table. If there is already an element
143 * equal to elem in the hash table, then the already existing element
144 * will be returned and the new element will not be inserted.
145 * Otherwise returns NULL.
147 static dmu_buf_impl_t *
148 dbuf_hash_insert(dmu_buf_impl_t *db)
150 dbuf_hash_table_t *h = &dbuf_hash_table;
151 objset_t *os = db->db_objset;
152 uint64_t obj = db->db.db_object;
153 int level = db->db_level;
154 uint64_t blkid = db->db_blkid;
155 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
156 uint64_t idx = hv & h->hash_table_mask;
159 mutex_enter(DBUF_HASH_MUTEX(h, idx));
160 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
161 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
162 mutex_enter(&dbf->db_mtx);
163 if (dbf->db_state != DB_EVICTING) {
164 mutex_exit(DBUF_HASH_MUTEX(h, idx));
167 mutex_exit(&dbf->db_mtx);
171 mutex_enter(&db->db_mtx);
172 db->db_hash_next = h->hash_table[idx];
173 h->hash_table[idx] = db;
174 mutex_exit(DBUF_HASH_MUTEX(h, idx));
175 atomic_add_64(&dbuf_hash_count, 1);
181 * Remove an entry from the hash table. This operation will
182 * fail if there are any existing holds on the db.
185 dbuf_hash_remove(dmu_buf_impl_t *db)
187 dbuf_hash_table_t *h = &dbuf_hash_table;
188 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object,
189 db->db_level, db->db_blkid);
190 uint64_t idx = hv & h->hash_table_mask;
191 dmu_buf_impl_t *dbf, **dbp;
194 * We musn't hold db_mtx to maintin lock ordering:
195 * DBUF_HASH_MUTEX > db_mtx.
197 ASSERT(refcount_is_zero(&db->db_holds));
198 ASSERT(db->db_state == DB_EVICTING);
199 ASSERT(!MUTEX_HELD(&db->db_mtx));
201 mutex_enter(DBUF_HASH_MUTEX(h, idx));
202 dbp = &h->hash_table[idx];
203 while ((dbf = *dbp) != db) {
204 dbp = &dbf->db_hash_next;
207 *dbp = db->db_hash_next;
208 db->db_hash_next = NULL;
209 mutex_exit(DBUF_HASH_MUTEX(h, idx));
210 atomic_add_64(&dbuf_hash_count, -1);
213 static arc_evict_func_t dbuf_do_evict;
216 dbuf_evict_user(dmu_buf_impl_t *db)
218 ASSERT(MUTEX_HELD(&db->db_mtx));
220 if (db->db_level != 0 || db->db_evict_func == NULL)
223 if (db->db_user_data_ptr_ptr)
224 *db->db_user_data_ptr_ptr = db->db.db_data;
225 db->db_evict_func(&db->db, db->db_user_ptr);
226 db->db_user_ptr = NULL;
227 db->db_user_data_ptr_ptr = NULL;
228 db->db_evict_func = NULL;
232 dbuf_is_metadata(dmu_buf_impl_t *db)
234 if (db->db_level > 0) {
237 boolean_t is_metadata;
240 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type);
243 return (is_metadata);
248 dbuf_evict(dmu_buf_impl_t *db)
250 ASSERT(MUTEX_HELD(&db->db_mtx));
251 ASSERT(db->db_buf == NULL);
252 ASSERT(db->db_data_pending == NULL);
261 uint64_t hsize = 1ULL << 16;
262 dbuf_hash_table_t *h = &dbuf_hash_table;
266 * The hash table is big enough to fill all of physical memory
267 * with an average 4K block size. The table will take up
268 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
270 while (hsize * 4096 < (uint64_t)physmem * PAGESIZE)
274 h->hash_table_mask = hsize - 1;
275 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
276 if (h->hash_table == NULL) {
277 /* XXX - we should really return an error instead of assert */
278 ASSERT(hsize > (1ULL << 10));
283 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
284 sizeof (dmu_buf_impl_t),
285 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
287 for (i = 0; i < DBUF_MUTEXES; i++)
288 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
294 dbuf_hash_table_t *h = &dbuf_hash_table;
297 for (i = 0; i < DBUF_MUTEXES; i++)
298 mutex_destroy(&h->hash_mutexes[i]);
299 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
300 kmem_cache_destroy(dbuf_cache);
309 dbuf_verify(dmu_buf_impl_t *db)
312 dbuf_dirty_record_t *dr;
314 ASSERT(MUTEX_HELD(&db->db_mtx));
316 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
319 ASSERT(db->db_objset != NULL);
323 ASSERT(db->db_parent == NULL);
324 ASSERT(db->db_blkptr == NULL);
326 ASSERT3U(db->db.db_object, ==, dn->dn_object);
327 ASSERT3P(db->db_objset, ==, dn->dn_objset);
328 ASSERT3U(db->db_level, <, dn->dn_nlevels);
329 ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
330 db->db_blkid == DMU_SPILL_BLKID ||
331 !list_is_empty(&dn->dn_dbufs));
333 if (db->db_blkid == DMU_BONUS_BLKID) {
335 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
336 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID);
337 } else if (db->db_blkid == DMU_SPILL_BLKID) {
339 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
340 ASSERT0(db->db.db_offset);
342 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
345 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
346 ASSERT(dr->dr_dbuf == db);
348 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
349 ASSERT(dr->dr_dbuf == db);
352 * We can't assert that db_size matches dn_datablksz because it
353 * can be momentarily different when another thread is doing
356 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
357 dr = db->db_data_pending;
359 * It should only be modified in syncing context, so
360 * make sure we only have one copy of the data.
362 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
365 /* verify db->db_blkptr */
367 if (db->db_parent == dn->dn_dbuf) {
368 /* db is pointed to by the dnode */
369 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
370 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
371 ASSERT(db->db_parent == NULL);
373 ASSERT(db->db_parent != NULL);
374 if (db->db_blkid != DMU_SPILL_BLKID)
375 ASSERT3P(db->db_blkptr, ==,
376 &dn->dn_phys->dn_blkptr[db->db_blkid]);
378 /* db is pointed to by an indirect block */
379 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT;
380 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
381 ASSERT3U(db->db_parent->db.db_object, ==,
384 * dnode_grow_indblksz() can make this fail if we don't
385 * have the struct_rwlock. XXX indblksz no longer
386 * grows. safe to do this now?
388 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
389 ASSERT3P(db->db_blkptr, ==,
390 ((blkptr_t *)db->db_parent->db.db_data +
391 db->db_blkid % epb));
395 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
396 (db->db_buf == NULL || db->db_buf->b_data) &&
397 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID &&
398 db->db_state != DB_FILL && !dn->dn_free_txg) {
400 * If the blkptr isn't set but they have nonzero data,
401 * it had better be dirty, otherwise we'll lose that
402 * data when we evict this buffer.
404 if (db->db_dirtycnt == 0) {
405 uint64_t *buf = db->db.db_data;
408 for (i = 0; i < db->db.db_size >> 3; i++) {
418 dbuf_update_data(dmu_buf_impl_t *db)
420 ASSERT(MUTEX_HELD(&db->db_mtx));
421 if (db->db_level == 0 && db->db_user_data_ptr_ptr) {
422 ASSERT(!refcount_is_zero(&db->db_holds));
423 *db->db_user_data_ptr_ptr = db->db.db_data;
428 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
430 ASSERT(MUTEX_HELD(&db->db_mtx));
431 ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf));
434 ASSERT(buf->b_data != NULL);
435 db->db.db_data = buf->b_data;
436 if (!arc_released(buf))
437 arc_set_callback(buf, dbuf_do_evict, db);
438 dbuf_update_data(db);
441 db->db.db_data = NULL;
442 if (db->db_state != DB_NOFILL)
443 db->db_state = DB_UNCACHED;
448 * Loan out an arc_buf for read. Return the loaned arc_buf.
451 dbuf_loan_arcbuf(dmu_buf_impl_t *db)
455 mutex_enter(&db->db_mtx);
456 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
457 int blksz = db->db.db_size;
460 mutex_exit(&db->db_mtx);
461 DB_GET_SPA(&spa, db);
462 abuf = arc_loan_buf(spa, blksz);
463 bcopy(db->db.db_data, abuf->b_data, blksz);
466 arc_loan_inuse_buf(abuf, db);
467 dbuf_set_data(db, NULL);
468 mutex_exit(&db->db_mtx);
474 dbuf_whichblock(dnode_t *dn, uint64_t offset)
476 if (dn->dn_datablkshift) {
477 return (offset >> dn->dn_datablkshift);
479 ASSERT3U(offset, <, dn->dn_datablksz);
485 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
487 dmu_buf_impl_t *db = vdb;
489 mutex_enter(&db->db_mtx);
490 ASSERT3U(db->db_state, ==, DB_READ);
492 * All reads are synchronous, so we must have a hold on the dbuf
494 ASSERT(refcount_count(&db->db_holds) > 0);
495 ASSERT(db->db_buf == NULL);
496 ASSERT(db->db.db_data == NULL);
497 if (db->db_level == 0 && db->db_freed_in_flight) {
498 /* we were freed in flight; disregard any error */
499 arc_release(buf, db);
500 bzero(buf->b_data, db->db.db_size);
502 db->db_freed_in_flight = FALSE;
503 dbuf_set_data(db, buf);
504 db->db_state = DB_CACHED;
505 } else if (zio == NULL || zio->io_error == 0) {
506 dbuf_set_data(db, buf);
507 db->db_state = DB_CACHED;
509 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
510 ASSERT3P(db->db_buf, ==, NULL);
511 VERIFY(arc_buf_remove_ref(buf, db));
512 db->db_state = DB_UNCACHED;
514 cv_broadcast(&db->db_changed);
515 dbuf_rele_and_unlock(db, NULL);
519 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
524 uint32_t aflags = ARC_NOWAIT;
528 ASSERT(!refcount_is_zero(&db->db_holds));
529 /* We need the struct_rwlock to prevent db_blkptr from changing. */
530 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
531 ASSERT(MUTEX_HELD(&db->db_mtx));
532 ASSERT(db->db_state == DB_UNCACHED);
533 ASSERT(db->db_buf == NULL);
535 if (db->db_blkid == DMU_BONUS_BLKID) {
536 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
538 ASSERT3U(bonuslen, <=, db->db.db_size);
539 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
540 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
541 if (bonuslen < DN_MAX_BONUSLEN)
542 bzero(db->db.db_data, DN_MAX_BONUSLEN);
544 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
546 dbuf_update_data(db);
547 db->db_state = DB_CACHED;
548 mutex_exit(&db->db_mtx);
553 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
554 * processes the delete record and clears the bp while we are waiting
555 * for the dn_mtx (resulting in a "no" from block_freed).
557 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
558 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
559 BP_IS_HOLE(db->db_blkptr)))) {
560 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
562 dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa,
563 db->db.db_size, db, type));
565 bzero(db->db.db_data, db->db.db_size);
566 db->db_state = DB_CACHED;
567 *flags |= DB_RF_CACHED;
568 mutex_exit(&db->db_mtx);
572 spa = dn->dn_objset->os_spa;
575 db->db_state = DB_READ;
576 mutex_exit(&db->db_mtx);
578 if (DBUF_IS_L2CACHEABLE(db))
579 aflags |= ARC_L2CACHE;
580 if (DBUF_IS_L2COMPRESSIBLE(db))
581 aflags |= ARC_L2COMPRESS;
583 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
584 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
585 db->db.db_object, db->db_level, db->db_blkid);
587 dbuf_add_ref(db, NULL);
589 (void) arc_read(zio, spa, db->db_blkptr,
590 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
591 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
593 if (aflags & ARC_CACHED)
594 *flags |= DB_RF_CACHED;
598 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
601 int havepzio = (zio != NULL);
606 * We don't have to hold the mutex to check db_state because it
607 * can't be freed while we have a hold on the buffer.
609 ASSERT(!refcount_is_zero(&db->db_holds));
611 if (db->db_state == DB_NOFILL)
612 return (SET_ERROR(EIO));
616 if ((flags & DB_RF_HAVESTRUCT) == 0)
617 rw_enter(&dn->dn_struct_rwlock, RW_READER);
619 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
620 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL &&
621 DBUF_IS_CACHEABLE(db);
623 mutex_enter(&db->db_mtx);
624 if (db->db_state == DB_CACHED) {
625 mutex_exit(&db->db_mtx);
627 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
628 db->db.db_size, TRUE);
629 if ((flags & DB_RF_HAVESTRUCT) == 0)
630 rw_exit(&dn->dn_struct_rwlock);
632 } else if (db->db_state == DB_UNCACHED) {
633 spa_t *spa = dn->dn_objset->os_spa;
636 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
637 dbuf_read_impl(db, zio, &flags);
639 /* dbuf_read_impl has dropped db_mtx for us */
642 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
643 db->db.db_size, flags & DB_RF_CACHED);
645 if ((flags & DB_RF_HAVESTRUCT) == 0)
646 rw_exit(&dn->dn_struct_rwlock);
653 * Another reader came in while the dbuf was in flight
654 * between UNCACHED and CACHED. Either a writer will finish
655 * writing the buffer (sending the dbuf to CACHED) or the
656 * first reader's request will reach the read_done callback
657 * and send the dbuf to CACHED. Otherwise, a failure
658 * occurred and the dbuf went to UNCACHED.
660 mutex_exit(&db->db_mtx);
662 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
663 db->db.db_size, TRUE);
664 if ((flags & DB_RF_HAVESTRUCT) == 0)
665 rw_exit(&dn->dn_struct_rwlock);
668 /* Skip the wait per the caller's request. */
669 mutex_enter(&db->db_mtx);
670 if ((flags & DB_RF_NEVERWAIT) == 0) {
671 while (db->db_state == DB_READ ||
672 db->db_state == DB_FILL) {
673 ASSERT(db->db_state == DB_READ ||
674 (flags & DB_RF_HAVESTRUCT) == 0);
675 cv_wait(&db->db_changed, &db->db_mtx);
677 if (db->db_state == DB_UNCACHED)
678 err = SET_ERROR(EIO);
680 mutex_exit(&db->db_mtx);
683 ASSERT(err || havepzio || db->db_state == DB_CACHED);
688 dbuf_noread(dmu_buf_impl_t *db)
690 ASSERT(!refcount_is_zero(&db->db_holds));
691 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
692 mutex_enter(&db->db_mtx);
693 while (db->db_state == DB_READ || db->db_state == DB_FILL)
694 cv_wait(&db->db_changed, &db->db_mtx);
695 if (db->db_state == DB_UNCACHED) {
696 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
699 ASSERT(db->db_buf == NULL);
700 ASSERT(db->db.db_data == NULL);
701 DB_GET_SPA(&spa, db);
702 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type));
703 db->db_state = DB_FILL;
704 } else if (db->db_state == DB_NOFILL) {
705 dbuf_set_data(db, NULL);
707 ASSERT3U(db->db_state, ==, DB_CACHED);
709 mutex_exit(&db->db_mtx);
713 * This is our just-in-time copy function. It makes a copy of
714 * buffers, that have been modified in a previous transaction
715 * group, before we modify them in the current active group.
717 * This function is used in two places: when we are dirtying a
718 * buffer for the first time in a txg, and when we are freeing
719 * a range in a dnode that includes this buffer.
721 * Note that when we are called from dbuf_free_range() we do
722 * not put a hold on the buffer, we just traverse the active
723 * dbuf list for the dnode.
726 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
728 dbuf_dirty_record_t *dr = db->db_last_dirty;
730 ASSERT(MUTEX_HELD(&db->db_mtx));
731 ASSERT(db->db.db_data != NULL);
732 ASSERT(db->db_level == 0);
733 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT);
736 (dr->dt.dl.dr_data !=
737 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf)))
741 * If the last dirty record for this dbuf has not yet synced
742 * and its referencing the dbuf data, either:
743 * reset the reference to point to a new copy,
744 * or (if there a no active holders)
745 * just null out the current db_data pointer.
747 ASSERT(dr->dr_txg >= txg - 2);
748 if (db->db_blkid == DMU_BONUS_BLKID) {
749 /* Note that the data bufs here are zio_bufs */
750 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
751 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
752 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
753 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
754 int size = db->db.db_size;
755 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
758 DB_GET_SPA(&spa, db);
759 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type);
760 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
762 dbuf_set_data(db, NULL);
767 dbuf_unoverride(dbuf_dirty_record_t *dr)
769 dmu_buf_impl_t *db = dr->dr_dbuf;
770 blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
771 uint64_t txg = dr->dr_txg;
773 ASSERT(MUTEX_HELD(&db->db_mtx));
774 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
775 ASSERT(db->db_level == 0);
777 if (db->db_blkid == DMU_BONUS_BLKID ||
778 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
781 ASSERT(db->db_data_pending != dr);
783 /* free this block */
784 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite) {
787 DB_GET_SPA(&spa, db);
788 zio_free(spa, txg, bp);
790 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
791 dr->dt.dl.dr_nopwrite = B_FALSE;
794 * Release the already-written buffer, so we leave it in
795 * a consistent dirty state. Note that all callers are
796 * modifying the buffer, so they will immediately do
797 * another (redundant) arc_release(). Therefore, leave
798 * the buf thawed to save the effort of freezing &
799 * immediately re-thawing it.
801 arc_release(dr->dt.dl.dr_data, db);
805 * Evict (if its unreferenced) or clear (if its referenced) any level-0
806 * data blocks in the free range, so that any future readers will find
807 * empty blocks. Also, if we happen across any level-1 dbufs in the
808 * range that have not already been marked dirty, mark them dirty so
809 * they stay in memory.
811 * This is a no-op if the dataset is in the middle of an incremental
812 * receive; see comment below for details.
815 dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
817 dmu_buf_impl_t *db, *db_next;
818 uint64_t txg = tx->tx_txg;
819 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
820 uint64_t first_l1 = start >> epbs;
821 uint64_t last_l1 = end >> epbs;
823 if (end > dn->dn_maxblkid && (end != DMU_SPILL_BLKID)) {
824 end = dn->dn_maxblkid;
825 last_l1 = end >> epbs;
827 dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
829 mutex_enter(&dn->dn_dbufs_mtx);
830 if (start >= dn->dn_unlisted_l0_blkid * dn->dn_datablksz) {
831 /* There can't be any dbufs in this range; no need to search. */
832 mutex_exit(&dn->dn_dbufs_mtx);
834 } else if (dmu_objset_is_receiving(dn->dn_objset)) {
836 * If we are receiving, we expect there to be no dbufs in
837 * the range to be freed, because receive modifies each
838 * block at most once, and in offset order. If this is
839 * not the case, it can lead to performance problems,
840 * so note that we unexpectedly took the slow path.
842 atomic_inc_64(&zfs_free_range_recv_miss);
845 for (db = list_head(&dn->dn_dbufs); db != NULL; db = db_next) {
846 db_next = list_next(&dn->dn_dbufs, db);
847 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
849 if (db->db_level == 1 &&
850 db->db_blkid >= first_l1 && db->db_blkid <= last_l1) {
851 mutex_enter(&db->db_mtx);
852 if (db->db_last_dirty &&
853 db->db_last_dirty->dr_txg < txg) {
854 dbuf_add_ref(db, FTAG);
855 mutex_exit(&db->db_mtx);
856 dbuf_will_dirty(db, tx);
859 mutex_exit(&db->db_mtx);
863 if (db->db_level != 0)
865 dprintf_dbuf(db, "found buf %s\n", "");
866 if (db->db_blkid < start || db->db_blkid > end)
869 /* found a level 0 buffer in the range */
870 mutex_enter(&db->db_mtx);
871 if (dbuf_undirty(db, tx)) {
872 /* mutex has been dropped and dbuf destroyed */
876 if (db->db_state == DB_UNCACHED ||
877 db->db_state == DB_NOFILL ||
878 db->db_state == DB_EVICTING) {
879 ASSERT(db->db.db_data == NULL);
880 mutex_exit(&db->db_mtx);
883 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
884 /* will be handled in dbuf_read_done or dbuf_rele */
885 db->db_freed_in_flight = TRUE;
886 mutex_exit(&db->db_mtx);
889 if (refcount_count(&db->db_holds) == 0) {
894 /* The dbuf is referenced */
896 if (db->db_last_dirty != NULL) {
897 dbuf_dirty_record_t *dr = db->db_last_dirty;
899 if (dr->dr_txg == txg) {
901 * This buffer is "in-use", re-adjust the file
902 * size to reflect that this buffer may
903 * contain new data when we sync.
905 if (db->db_blkid != DMU_SPILL_BLKID &&
906 db->db_blkid > dn->dn_maxblkid)
907 dn->dn_maxblkid = db->db_blkid;
911 * This dbuf is not dirty in the open context.
912 * Either uncache it (if its not referenced in
913 * the open context) or reset its contents to
916 dbuf_fix_old_data(db, txg);
919 /* clear the contents if its cached */
920 if (db->db_state == DB_CACHED) {
921 ASSERT(db->db.db_data != NULL);
922 arc_release(db->db_buf, db);
923 bzero(db->db.db_data, db->db.db_size);
924 arc_buf_freeze(db->db_buf);
927 mutex_exit(&db->db_mtx);
929 mutex_exit(&dn->dn_dbufs_mtx);
933 dbuf_block_freeable(dmu_buf_impl_t *db)
935 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
936 uint64_t birth_txg = 0;
939 * We don't need any locking to protect db_blkptr:
940 * If it's syncing, then db_last_dirty will be set
941 * so we'll ignore db_blkptr.
943 ASSERT(MUTEX_HELD(&db->db_mtx));
944 if (db->db_last_dirty)
945 birth_txg = db->db_last_dirty->dr_txg;
946 else if (db->db_blkptr)
947 birth_txg = db->db_blkptr->blk_birth;
950 * If we don't exist or are in a snapshot, we can't be freed.
951 * Don't pass the bp to dsl_dataset_block_freeable() since we
952 * are holding the db_mtx lock and might deadlock if we are
953 * prefetching a dedup-ed block.
956 return (ds == NULL ||
957 dsl_dataset_block_freeable(ds, NULL, birth_txg));
963 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
965 arc_buf_t *buf, *obuf;
966 int osize = db->db.db_size;
967 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
970 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
975 /* XXX does *this* func really need the lock? */
976 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
979 * This call to dbuf_will_dirty() with the dn_struct_rwlock held
980 * is OK, because there can be no other references to the db
981 * when we are changing its size, so no concurrent DB_FILL can
985 * XXX we should be doing a dbuf_read, checking the return
986 * value and returning that up to our callers
988 dbuf_will_dirty(db, tx);
990 /* create the data buffer for the new block */
991 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type);
993 /* copy old block data to the new block */
995 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
996 /* zero the remainder */
998 bzero((uint8_t *)buf->b_data + osize, size - osize);
1000 mutex_enter(&db->db_mtx);
1001 dbuf_set_data(db, buf);
1002 VERIFY(arc_buf_remove_ref(obuf, db));
1003 db->db.db_size = size;
1005 if (db->db_level == 0) {
1006 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
1007 db->db_last_dirty->dt.dl.dr_data = buf;
1009 mutex_exit(&db->db_mtx);
1011 dnode_willuse_space(dn, size-osize, tx);
1016 dbuf_release_bp(dmu_buf_impl_t *db)
1020 DB_GET_OBJSET(&os, db);
1021 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
1022 ASSERT(arc_released(os->os_phys_buf) ||
1023 list_link_active(&os->os_dsl_dataset->ds_synced_link));
1024 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf));
1026 (void) arc_release(db->db_buf, db);
1029 dbuf_dirty_record_t *
1030 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1034 dbuf_dirty_record_t **drp, *dr;
1035 int drop_struct_lock = FALSE;
1036 boolean_t do_free_accounting = B_FALSE;
1037 int txgoff = tx->tx_txg & TXG_MASK;
1039 ASSERT(tx->tx_txg != 0);
1040 ASSERT(!refcount_is_zero(&db->db_holds));
1041 DMU_TX_DIRTY_BUF(tx, db);
1046 * Shouldn't dirty a regular buffer in syncing context. Private
1047 * objects may be dirtied in syncing context, but only if they
1048 * were already pre-dirtied in open context.
1050 ASSERT(!dmu_tx_is_syncing(tx) ||
1051 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
1052 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1053 dn->dn_objset->os_dsl_dataset == NULL);
1055 * We make this assert for private objects as well, but after we
1056 * check if we're already dirty. They are allowed to re-dirty
1057 * in syncing context.
1059 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1060 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1061 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1063 mutex_enter(&db->db_mtx);
1065 * XXX make this true for indirects too? The problem is that
1066 * transactions created with dmu_tx_create_assigned() from
1067 * syncing context don't bother holding ahead.
1069 ASSERT(db->db_level != 0 ||
1070 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
1071 db->db_state == DB_NOFILL);
1073 mutex_enter(&dn->dn_mtx);
1075 * Don't set dirtyctx to SYNC if we're just modifying this as we
1076 * initialize the objset.
1078 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
1079 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
1081 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
1082 ASSERT(dn->dn_dirtyctx_firstset == NULL);
1083 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
1085 mutex_exit(&dn->dn_mtx);
1087 if (db->db_blkid == DMU_SPILL_BLKID)
1088 dn->dn_have_spill = B_TRUE;
1091 * If this buffer is already dirty, we're done.
1093 drp = &db->db_last_dirty;
1094 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
1095 db->db.db_object == DMU_META_DNODE_OBJECT);
1096 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
1098 if (dr && dr->dr_txg == tx->tx_txg) {
1101 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
1103 * If this buffer has already been written out,
1104 * we now need to reset its state.
1106 dbuf_unoverride(dr);
1107 if (db->db.db_object != DMU_META_DNODE_OBJECT &&
1108 db->db_state != DB_NOFILL)
1109 arc_buf_thaw(db->db_buf);
1111 mutex_exit(&db->db_mtx);
1116 * Only valid if not already dirty.
1118 ASSERT(dn->dn_object == 0 ||
1119 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1120 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1122 ASSERT3U(dn->dn_nlevels, >, db->db_level);
1123 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
1124 dn->dn_phys->dn_nlevels > db->db_level ||
1125 dn->dn_next_nlevels[txgoff] > db->db_level ||
1126 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
1127 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
1130 * We should only be dirtying in syncing context if it's the
1131 * mos or we're initializing the os or it's a special object.
1132 * However, we are allowed to dirty in syncing context provided
1133 * we already dirtied it in open context. Hence we must make
1134 * this assertion only if we're not already dirty.
1137 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1138 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
1139 ASSERT(db->db.db_size != 0);
1141 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1143 if (db->db_blkid != DMU_BONUS_BLKID) {
1145 * Update the accounting.
1146 * Note: we delay "free accounting" until after we drop
1147 * the db_mtx. This keeps us from grabbing other locks
1148 * (and possibly deadlocking) in bp_get_dsize() while
1149 * also holding the db_mtx.
1151 dnode_willuse_space(dn, db->db.db_size, tx);
1152 do_free_accounting = dbuf_block_freeable(db);
1156 * If this buffer is dirty in an old transaction group we need
1157 * to make a copy of it so that the changes we make in this
1158 * transaction group won't leak out when we sync the older txg.
1160 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP);
1161 if (db->db_level == 0) {
1162 void *data_old = db->db_buf;
1164 if (db->db_state != DB_NOFILL) {
1165 if (db->db_blkid == DMU_BONUS_BLKID) {
1166 dbuf_fix_old_data(db, tx->tx_txg);
1167 data_old = db->db.db_data;
1168 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1170 * Release the data buffer from the cache so
1171 * that we can modify it without impacting
1172 * possible other users of this cached data
1173 * block. Note that indirect blocks and
1174 * private objects are not released until the
1175 * syncing state (since they are only modified
1178 arc_release(db->db_buf, db);
1179 dbuf_fix_old_data(db, tx->tx_txg);
1180 data_old = db->db_buf;
1182 ASSERT(data_old != NULL);
1184 dr->dt.dl.dr_data = data_old;
1186 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1187 list_create(&dr->dt.di.dr_children,
1188 sizeof (dbuf_dirty_record_t),
1189 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1191 if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL)
1192 dr->dr_accounted = db->db.db_size;
1194 dr->dr_txg = tx->tx_txg;
1199 * We could have been freed_in_flight between the dbuf_noread
1200 * and dbuf_dirty. We win, as though the dbuf_noread() had
1201 * happened after the free.
1203 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1204 db->db_blkid != DMU_SPILL_BLKID) {
1205 mutex_enter(&dn->dn_mtx);
1206 dnode_clear_range(dn, db->db_blkid, 1, tx);
1207 mutex_exit(&dn->dn_mtx);
1208 db->db_freed_in_flight = FALSE;
1212 * This buffer is now part of this txg
1214 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1215 db->db_dirtycnt += 1;
1216 ASSERT3U(db->db_dirtycnt, <=, 3);
1218 mutex_exit(&db->db_mtx);
1220 if (db->db_blkid == DMU_BONUS_BLKID ||
1221 db->db_blkid == DMU_SPILL_BLKID) {
1222 mutex_enter(&dn->dn_mtx);
1223 ASSERT(!list_link_active(&dr->dr_dirty_node));
1224 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1225 mutex_exit(&dn->dn_mtx);
1226 dnode_setdirty(dn, tx);
1229 } else if (do_free_accounting) {
1230 blkptr_t *bp = db->db_blkptr;
1231 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1232 bp_get_dsize(os->os_spa, bp) : db->db.db_size;
1234 * This is only a guess -- if the dbuf is dirty
1235 * in a previous txg, we don't know how much
1236 * space it will use on disk yet. We should
1237 * really have the struct_rwlock to access
1238 * db_blkptr, but since this is just a guess,
1239 * it's OK if we get an odd answer.
1241 ddt_prefetch(os->os_spa, bp);
1242 dnode_willuse_space(dn, -willfree, tx);
1245 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1246 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1247 drop_struct_lock = TRUE;
1250 if (db->db_level == 0) {
1251 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1252 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1255 if (db->db_level+1 < dn->dn_nlevels) {
1256 dmu_buf_impl_t *parent = db->db_parent;
1257 dbuf_dirty_record_t *di;
1258 int parent_held = FALSE;
1260 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1261 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1263 parent = dbuf_hold_level(dn, db->db_level+1,
1264 db->db_blkid >> epbs, FTAG);
1265 ASSERT(parent != NULL);
1268 if (drop_struct_lock)
1269 rw_exit(&dn->dn_struct_rwlock);
1270 ASSERT3U(db->db_level+1, ==, parent->db_level);
1271 di = dbuf_dirty(parent, tx);
1273 dbuf_rele(parent, FTAG);
1275 mutex_enter(&db->db_mtx);
1277 * Since we've dropped the mutex, it's possible that
1278 * dbuf_undirty() might have changed this out from under us.
1280 if (db->db_last_dirty == dr ||
1281 dn->dn_object == DMU_META_DNODE_OBJECT) {
1282 mutex_enter(&di->dt.di.dr_mtx);
1283 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1284 ASSERT(!list_link_active(&dr->dr_dirty_node));
1285 list_insert_tail(&di->dt.di.dr_children, dr);
1286 mutex_exit(&di->dt.di.dr_mtx);
1289 mutex_exit(&db->db_mtx);
1291 ASSERT(db->db_level+1 == dn->dn_nlevels);
1292 ASSERT(db->db_blkid < dn->dn_nblkptr);
1293 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf);
1294 mutex_enter(&dn->dn_mtx);
1295 ASSERT(!list_link_active(&dr->dr_dirty_node));
1296 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1297 mutex_exit(&dn->dn_mtx);
1298 if (drop_struct_lock)
1299 rw_exit(&dn->dn_struct_rwlock);
1302 dnode_setdirty(dn, tx);
1308 * Undirty a buffer in the transaction group referenced by the given
1309 * transaction. Return whether this evicted the dbuf.
1312 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1315 uint64_t txg = tx->tx_txg;
1316 dbuf_dirty_record_t *dr, **drp;
1319 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1320 ASSERT0(db->db_level);
1321 ASSERT(MUTEX_HELD(&db->db_mtx));
1324 * If this buffer is not dirty, we're done.
1326 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1327 if (dr->dr_txg <= txg)
1329 if (dr == NULL || dr->dr_txg < txg)
1331 ASSERT(dr->dr_txg == txg);
1332 ASSERT(dr->dr_dbuf == db);
1337 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1339 ASSERT(db->db.db_size != 0);
1342 * Any space we accounted for in dp_dirty_* will be cleaned up by
1343 * dsl_pool_sync(). This is relatively rare so the discrepancy
1344 * is not a big deal.
1350 * Note that there are three places in dbuf_dirty()
1351 * where this dirty record may be put on a list.
1352 * Make sure to do a list_remove corresponding to
1353 * every one of those list_insert calls.
1355 if (dr->dr_parent) {
1356 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1357 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1358 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1359 } else if (db->db_blkid == DMU_SPILL_BLKID ||
1360 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_state != DB_NOFILL) {
1369 dbuf_unoverride(dr);
1371 ASSERT(db->db_buf != NULL);
1372 ASSERT(dr->dt.dl.dr_data != NULL);
1373 if (dr->dt.dl.dr_data != db->db_buf)
1374 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db));
1376 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1378 ASSERT(db->db_dirtycnt > 0);
1379 db->db_dirtycnt -= 1;
1381 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1382 arc_buf_t *buf = db->db_buf;
1384 ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
1385 dbuf_set_data(db, NULL);
1386 VERIFY(arc_buf_remove_ref(buf, db));
1394 #pragma weak dmu_buf_will_dirty = dbuf_will_dirty
1396 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1398 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1400 ASSERT(tx->tx_txg != 0);
1401 ASSERT(!refcount_is_zero(&db->db_holds));
1404 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
1405 rf |= DB_RF_HAVESTRUCT;
1407 (void) dbuf_read(db, NULL, rf);
1408 (void) dbuf_dirty(db, tx);
1412 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1414 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1416 db->db_state = DB_NOFILL;
1418 dmu_buf_will_fill(db_fake, tx);
1422 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1424 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1426 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1427 ASSERT(tx->tx_txg != 0);
1428 ASSERT(db->db_level == 0);
1429 ASSERT(!refcount_is_zero(&db->db_holds));
1431 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1432 dmu_tx_private_ok(tx));
1435 (void) dbuf_dirty(db, tx);
1438 #pragma weak dmu_buf_fill_done = dbuf_fill_done
1441 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1443 mutex_enter(&db->db_mtx);
1446 if (db->db_state == DB_FILL) {
1447 if (db->db_level == 0 && db->db_freed_in_flight) {
1448 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1449 /* we were freed while filling */
1450 /* XXX dbuf_undirty? */
1451 bzero(db->db.db_data, db->db.db_size);
1452 db->db_freed_in_flight = FALSE;
1454 db->db_state = DB_CACHED;
1455 cv_broadcast(&db->db_changed);
1457 mutex_exit(&db->db_mtx);
1461 * Directly assign a provided arc buf to a given dbuf if it's not referenced
1462 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
1465 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
1467 ASSERT(!refcount_is_zero(&db->db_holds));
1468 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1469 ASSERT(db->db_level == 0);
1470 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
1471 ASSERT(buf != NULL);
1472 ASSERT(arc_buf_size(buf) == db->db.db_size);
1473 ASSERT(tx->tx_txg != 0);
1475 arc_return_buf(buf, db);
1476 ASSERT(arc_released(buf));
1478 mutex_enter(&db->db_mtx);
1480 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1481 cv_wait(&db->db_changed, &db->db_mtx);
1483 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
1485 if (db->db_state == DB_CACHED &&
1486 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
1487 mutex_exit(&db->db_mtx);
1488 (void) dbuf_dirty(db, tx);
1489 bcopy(buf->b_data, db->db.db_data, db->db.db_size);
1490 VERIFY(arc_buf_remove_ref(buf, db));
1491 xuio_stat_wbuf_copied();
1495 xuio_stat_wbuf_nocopy();
1496 if (db->db_state == DB_CACHED) {
1497 dbuf_dirty_record_t *dr = db->db_last_dirty;
1499 ASSERT(db->db_buf != NULL);
1500 if (dr != NULL && dr->dr_txg == tx->tx_txg) {
1501 ASSERT(dr->dt.dl.dr_data == db->db_buf);
1502 if (!arc_released(db->db_buf)) {
1503 ASSERT(dr->dt.dl.dr_override_state ==
1505 arc_release(db->db_buf, db);
1507 dr->dt.dl.dr_data = buf;
1508 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1509 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
1510 arc_release(db->db_buf, db);
1511 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1515 ASSERT(db->db_buf == NULL);
1516 dbuf_set_data(db, buf);
1517 db->db_state = DB_FILL;
1518 mutex_exit(&db->db_mtx);
1519 (void) dbuf_dirty(db, tx);
1520 dbuf_fill_done(db, tx);
1524 * "Clear" the contents of this dbuf. This will mark the dbuf
1525 * EVICTING and clear *most* of its references. Unfortunately,
1526 * when we are not holding the dn_dbufs_mtx, we can't clear the
1527 * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
1528 * in this case. For callers from the DMU we will usually see:
1529 * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy()
1530 * For the arc callback, we will usually see:
1531 * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
1532 * Sometimes, though, we will get a mix of these two:
1533 * DMU: dbuf_clear()->arc_buf_evict()
1534 * ARC: dbuf_do_evict()->dbuf_destroy()
1537 dbuf_clear(dmu_buf_impl_t *db)
1540 dmu_buf_impl_t *parent = db->db_parent;
1541 dmu_buf_impl_t *dndb;
1542 int dbuf_gone = FALSE;
1544 ASSERT(MUTEX_HELD(&db->db_mtx));
1545 ASSERT(refcount_is_zero(&db->db_holds));
1547 dbuf_evict_user(db);
1549 if (db->db_state == DB_CACHED) {
1550 ASSERT(db->db.db_data != NULL);
1551 if (db->db_blkid == DMU_BONUS_BLKID) {
1552 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1553 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1555 db->db.db_data = NULL;
1556 db->db_state = DB_UNCACHED;
1559 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
1560 ASSERT(db->db_data_pending == NULL);
1562 db->db_state = DB_EVICTING;
1563 db->db_blkptr = NULL;
1568 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1569 list_remove(&dn->dn_dbufs, db);
1570 (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1574 * Decrementing the dbuf count means that the hold corresponding
1575 * to the removed dbuf is no longer discounted in dnode_move(),
1576 * so the dnode cannot be moved until after we release the hold.
1577 * The membar_producer() ensures visibility of the decremented
1578 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually
1582 db->db_dnode_handle = NULL;
1588 dbuf_gone = arc_buf_evict(db->db_buf);
1591 mutex_exit(&db->db_mtx);
1594 * If this dbuf is referenced from an indirect dbuf,
1595 * decrement the ref count on the indirect dbuf.
1597 if (parent && parent != dndb)
1598 dbuf_rele(parent, db);
1602 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1603 dmu_buf_impl_t **parentp, blkptr_t **bpp)
1610 ASSERT(blkid != DMU_BONUS_BLKID);
1612 if (blkid == DMU_SPILL_BLKID) {
1613 mutex_enter(&dn->dn_mtx);
1614 if (dn->dn_have_spill &&
1615 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
1616 *bpp = &dn->dn_phys->dn_spill;
1619 dbuf_add_ref(dn->dn_dbuf, NULL);
1620 *parentp = dn->dn_dbuf;
1621 mutex_exit(&dn->dn_mtx);
1625 if (dn->dn_phys->dn_nlevels == 0)
1628 nlevels = dn->dn_phys->dn_nlevels;
1630 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1632 ASSERT3U(level * epbs, <, 64);
1633 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1634 if (level >= nlevels ||
1635 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
1636 /* the buffer has no parent yet */
1637 return (SET_ERROR(ENOENT));
1638 } else if (level < nlevels-1) {
1639 /* this block is referenced from an indirect block */
1640 int err = dbuf_hold_impl(dn, level+1,
1641 blkid >> epbs, fail_sparse, NULL, parentp);
1644 err = dbuf_read(*parentp, NULL,
1645 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1647 dbuf_rele(*parentp, NULL);
1651 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1652 (blkid & ((1ULL << epbs) - 1));
1655 /* the block is referenced from the dnode */
1656 ASSERT3U(level, ==, nlevels-1);
1657 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1658 blkid < dn->dn_phys->dn_nblkptr);
1660 dbuf_add_ref(dn->dn_dbuf, NULL);
1661 *parentp = dn->dn_dbuf;
1663 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1668 static dmu_buf_impl_t *
1669 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1670 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1672 objset_t *os = dn->dn_objset;
1673 dmu_buf_impl_t *db, *odb;
1675 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1676 ASSERT(dn->dn_type != DMU_OT_NONE);
1678 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP);
1681 db->db.db_object = dn->dn_object;
1682 db->db_level = level;
1683 db->db_blkid = blkid;
1684 db->db_last_dirty = NULL;
1685 db->db_dirtycnt = 0;
1686 db->db_dnode_handle = dn->dn_handle;
1687 db->db_parent = parent;
1688 db->db_blkptr = blkptr;
1690 db->db_user_ptr = NULL;
1691 db->db_user_data_ptr_ptr = NULL;
1692 db->db_evict_func = NULL;
1693 db->db_immediate_evict = 0;
1694 db->db_freed_in_flight = 0;
1696 if (blkid == DMU_BONUS_BLKID) {
1697 ASSERT3P(parent, ==, dn->dn_dbuf);
1698 db->db.db_size = DN_MAX_BONUSLEN -
1699 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1700 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1701 db->db.db_offset = DMU_BONUS_BLKID;
1702 db->db_state = DB_UNCACHED;
1703 /* the bonus dbuf is not placed in the hash table */
1704 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1706 } else if (blkid == DMU_SPILL_BLKID) {
1707 db->db.db_size = (blkptr != NULL) ?
1708 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE;
1709 db->db.db_offset = 0;
1712 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz;
1713 db->db.db_size = blocksize;
1714 db->db.db_offset = db->db_blkid * blocksize;
1718 * Hold the dn_dbufs_mtx while we get the new dbuf
1719 * in the hash table *and* added to the dbufs list.
1720 * This prevents a possible deadlock with someone
1721 * trying to look up this dbuf before its added to the
1724 mutex_enter(&dn->dn_dbufs_mtx);
1725 db->db_state = DB_EVICTING;
1726 if ((odb = dbuf_hash_insert(db)) != NULL) {
1727 /* someone else inserted it first */
1728 kmem_cache_free(dbuf_cache, db);
1729 mutex_exit(&dn->dn_dbufs_mtx);
1732 list_insert_head(&dn->dn_dbufs, db);
1733 if (db->db_level == 0 && db->db_blkid >=
1734 dn->dn_unlisted_l0_blkid)
1735 dn->dn_unlisted_l0_blkid = db->db_blkid + 1;
1736 db->db_state = DB_UNCACHED;
1737 mutex_exit(&dn->dn_dbufs_mtx);
1738 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1740 if (parent && parent != dn->dn_dbuf)
1741 dbuf_add_ref(parent, db);
1743 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1744 refcount_count(&dn->dn_holds) > 0);
1745 (void) refcount_add(&dn->dn_holds, db);
1746 (void) atomic_inc_32_nv(&dn->dn_dbufs_count);
1748 dprintf_dbuf(db, "db=%p\n", db);
1754 dbuf_do_evict(void *private)
1756 arc_buf_t *buf = private;
1757 dmu_buf_impl_t *db = buf->b_private;
1759 if (!MUTEX_HELD(&db->db_mtx))
1760 mutex_enter(&db->db_mtx);
1762 ASSERT(refcount_is_zero(&db->db_holds));
1764 if (db->db_state != DB_EVICTING) {
1765 ASSERT(db->db_state == DB_CACHED);
1770 mutex_exit(&db->db_mtx);
1777 dbuf_destroy(dmu_buf_impl_t *db)
1779 ASSERT(refcount_is_zero(&db->db_holds));
1781 if (db->db_blkid != DMU_BONUS_BLKID) {
1783 * If this dbuf is still on the dn_dbufs list,
1784 * remove it from that list.
1786 if (db->db_dnode_handle != NULL) {
1791 mutex_enter(&dn->dn_dbufs_mtx);
1792 list_remove(&dn->dn_dbufs, db);
1793 (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1794 mutex_exit(&dn->dn_dbufs_mtx);
1797 * Decrementing the dbuf count means that the hold
1798 * corresponding to the removed dbuf is no longer
1799 * discounted in dnode_move(), so the dnode cannot be
1800 * moved until after we release the hold.
1803 db->db_dnode_handle = NULL;
1805 dbuf_hash_remove(db);
1807 db->db_parent = NULL;
1810 ASSERT(!list_link_active(&db->db_link));
1811 ASSERT(db->db.db_data == NULL);
1812 ASSERT(db->db_hash_next == NULL);
1813 ASSERT(db->db_blkptr == NULL);
1814 ASSERT(db->db_data_pending == NULL);
1816 kmem_cache_free(dbuf_cache, db);
1817 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1821 dbuf_prefetch(dnode_t *dn, uint64_t blkid, zio_priority_t prio)
1823 dmu_buf_impl_t *db = NULL;
1824 blkptr_t *bp = NULL;
1826 ASSERT(blkid != DMU_BONUS_BLKID);
1827 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1829 if (dnode_block_freed(dn, blkid))
1832 /* dbuf_find() returns with db_mtx held */
1833 if (db = dbuf_find(dn, 0, blkid)) {
1835 * This dbuf is already in the cache. We assume that
1836 * it is already CACHED, or else about to be either
1839 mutex_exit(&db->db_mtx);
1843 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) {
1844 if (bp && !BP_IS_HOLE(bp)) {
1845 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
1846 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
1849 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1850 dn->dn_object, 0, blkid);
1852 (void) arc_read(NULL, dn->dn_objset->os_spa,
1853 bp, NULL, NULL, prio,
1854 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1858 dbuf_rele(db, NULL);
1863 * Returns with db_holds incremented, and db_mtx not held.
1864 * Note: dn_struct_rwlock must be held.
1867 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
1868 void *tag, dmu_buf_impl_t **dbp)
1870 dmu_buf_impl_t *db, *parent = NULL;
1872 ASSERT(blkid != DMU_BONUS_BLKID);
1873 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1874 ASSERT3U(dn->dn_nlevels, >, level);
1878 /* dbuf_find() returns with db_mtx held */
1879 db = dbuf_find(dn, level, blkid);
1882 blkptr_t *bp = NULL;
1885 ASSERT3P(parent, ==, NULL);
1886 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp);
1888 if (err == 0 && bp && BP_IS_HOLE(bp))
1889 err = SET_ERROR(ENOENT);
1892 dbuf_rele(parent, NULL);
1896 if (err && err != ENOENT)
1898 db = dbuf_create(dn, level, blkid, parent, bp);
1901 if (db->db_buf && refcount_is_zero(&db->db_holds)) {
1902 arc_buf_add_ref(db->db_buf, db);
1903 if (db->db_buf->b_data == NULL) {
1906 dbuf_rele(parent, NULL);
1911 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data);
1914 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf));
1917 * If this buffer is currently syncing out, and we are are
1918 * still referencing it from db_data, we need to make a copy
1919 * of it in case we decide we want to dirty it again in this txg.
1921 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1922 dn->dn_object != DMU_META_DNODE_OBJECT &&
1923 db->db_state == DB_CACHED && db->db_data_pending) {
1924 dbuf_dirty_record_t *dr = db->db_data_pending;
1926 if (dr->dt.dl.dr_data == db->db_buf) {
1927 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
1930 arc_buf_alloc(dn->dn_objset->os_spa,
1931 db->db.db_size, db, type));
1932 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data,
1937 (void) refcount_add(&db->db_holds, tag);
1938 dbuf_update_data(db);
1940 mutex_exit(&db->db_mtx);
1942 /* NOTE: we can't rele the parent until after we drop the db_mtx */
1944 dbuf_rele(parent, NULL);
1946 ASSERT3P(DB_DNODE(db), ==, dn);
1947 ASSERT3U(db->db_blkid, ==, blkid);
1948 ASSERT3U(db->db_level, ==, level);
1955 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
1958 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
1959 return (err ? NULL : db);
1963 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
1966 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
1967 return (err ? NULL : db);
1971 dbuf_create_bonus(dnode_t *dn)
1973 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
1975 ASSERT(dn->dn_bonus == NULL);
1976 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL);
1980 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx)
1982 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1985 if (db->db_blkid != DMU_SPILL_BLKID)
1986 return (SET_ERROR(ENOTSUP));
1988 blksz = SPA_MINBLOCKSIZE;
1989 if (blksz > SPA_MAXBLOCKSIZE)
1990 blksz = SPA_MAXBLOCKSIZE;
1992 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE);
1996 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
1997 dbuf_new_size(db, blksz, tx);
1998 rw_exit(&dn->dn_struct_rwlock);
2005 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx)
2007 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx);
2010 #pragma weak dmu_buf_add_ref = dbuf_add_ref
2012 dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
2014 int64_t holds = refcount_add(&db->db_holds, tag);
2019 * If you call dbuf_rele() you had better not be referencing the dnode handle
2020 * unless you have some other direct or indirect hold on the dnode. (An indirect
2021 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.)
2022 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the
2023 * dnode's parent dbuf evicting its dnode handles.
2025 #pragma weak dmu_buf_rele = dbuf_rele
2027 dbuf_rele(dmu_buf_impl_t *db, void *tag)
2029 mutex_enter(&db->db_mtx);
2030 dbuf_rele_and_unlock(db, tag);
2034 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
2035 * db_dirtycnt and db_holds to be updated atomically.
2038 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
2042 ASSERT(MUTEX_HELD(&db->db_mtx));
2046 * Remove the reference to the dbuf before removing its hold on the
2047 * dnode so we can guarantee in dnode_move() that a referenced bonus
2048 * buffer has a corresponding dnode hold.
2050 holds = refcount_remove(&db->db_holds, tag);
2054 * We can't freeze indirects if there is a possibility that they
2055 * may be modified in the current syncing context.
2057 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
2058 arc_buf_freeze(db->db_buf);
2060 if (holds == db->db_dirtycnt &&
2061 db->db_level == 0 && db->db_immediate_evict)
2062 dbuf_evict_user(db);
2065 if (db->db_blkid == DMU_BONUS_BLKID) {
2066 mutex_exit(&db->db_mtx);
2069 * If the dnode moves here, we cannot cross this barrier
2070 * until the move completes.
2073 (void) atomic_dec_32_nv(&DB_DNODE(db)->dn_dbufs_count);
2076 * The bonus buffer's dnode hold is no longer discounted
2077 * in dnode_move(). The dnode cannot move until after
2080 dnode_rele(DB_DNODE(db), db);
2081 } else if (db->db_buf == NULL) {
2083 * This is a special case: we never associated this
2084 * dbuf with any data allocated from the ARC.
2086 ASSERT(db->db_state == DB_UNCACHED ||
2087 db->db_state == DB_NOFILL);
2089 } else if (arc_released(db->db_buf)) {
2090 arc_buf_t *buf = db->db_buf;
2092 * This dbuf has anonymous data associated with it.
2094 dbuf_set_data(db, NULL);
2095 VERIFY(arc_buf_remove_ref(buf, db));
2098 VERIFY(!arc_buf_remove_ref(db->db_buf, db));
2101 * A dbuf will be eligible for eviction if either the
2102 * 'primarycache' property is set or a duplicate
2103 * copy of this buffer is already cached in the arc.
2105 * In the case of the 'primarycache' a buffer
2106 * is considered for eviction if it matches the
2107 * criteria set in the property.
2109 * To decide if our buffer is considered a
2110 * duplicate, we must call into the arc to determine
2111 * if multiple buffers are referencing the same
2112 * block on-disk. If so, then we simply evict
2115 if (!DBUF_IS_CACHEABLE(db) ||
2116 arc_buf_eviction_needed(db->db_buf))
2119 mutex_exit(&db->db_mtx);
2122 mutex_exit(&db->db_mtx);
2126 #pragma weak dmu_buf_refcount = dbuf_refcount
2128 dbuf_refcount(dmu_buf_impl_t *db)
2130 return (refcount_count(&db->db_holds));
2134 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
2135 dmu_buf_evict_func_t *evict_func)
2137 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
2138 user_data_ptr_ptr, evict_func));
2142 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
2143 dmu_buf_evict_func_t *evict_func)
2145 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2147 db->db_immediate_evict = TRUE;
2148 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
2149 user_data_ptr_ptr, evict_func));
2153 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr,
2154 void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func)
2156 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2157 ASSERT(db->db_level == 0);
2159 ASSERT((user_ptr == NULL) == (evict_func == NULL));
2161 mutex_enter(&db->db_mtx);
2163 if (db->db_user_ptr == old_user_ptr) {
2164 db->db_user_ptr = user_ptr;
2165 db->db_user_data_ptr_ptr = user_data_ptr_ptr;
2166 db->db_evict_func = evict_func;
2168 dbuf_update_data(db);
2170 old_user_ptr = db->db_user_ptr;
2173 mutex_exit(&db->db_mtx);
2174 return (old_user_ptr);
2178 dmu_buf_get_user(dmu_buf_t *db_fake)
2180 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2181 ASSERT(!refcount_is_zero(&db->db_holds));
2183 return (db->db_user_ptr);
2187 dmu_buf_freeable(dmu_buf_t *dbuf)
2189 boolean_t res = B_FALSE;
2190 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
2193 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
2194 db->db_blkptr, db->db_blkptr->blk_birth);
2200 dmu_buf_get_blkptr(dmu_buf_t *db)
2202 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db;
2203 return (dbi->db_blkptr);
2207 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
2209 /* ASSERT(dmu_tx_is_syncing(tx) */
2210 ASSERT(MUTEX_HELD(&db->db_mtx));
2212 if (db->db_blkptr != NULL)
2215 if (db->db_blkid == DMU_SPILL_BLKID) {
2216 db->db_blkptr = &dn->dn_phys->dn_spill;
2217 BP_ZERO(db->db_blkptr);
2220 if (db->db_level == dn->dn_phys->dn_nlevels-1) {
2222 * This buffer was allocated at a time when there was
2223 * no available blkptrs from the dnode, or it was
2224 * inappropriate to hook it in (i.e., nlevels mis-match).
2226 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr);
2227 ASSERT(db->db_parent == NULL);
2228 db->db_parent = dn->dn_dbuf;
2229 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid];
2232 dmu_buf_impl_t *parent = db->db_parent;
2233 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2235 ASSERT(dn->dn_phys->dn_nlevels > 1);
2236 if (parent == NULL) {
2237 mutex_exit(&db->db_mtx);
2238 rw_enter(&dn->dn_struct_rwlock, RW_READER);
2239 (void) dbuf_hold_impl(dn, db->db_level+1,
2240 db->db_blkid >> epbs, FALSE, db, &parent);
2241 rw_exit(&dn->dn_struct_rwlock);
2242 mutex_enter(&db->db_mtx);
2243 db->db_parent = parent;
2245 db->db_blkptr = (blkptr_t *)parent->db.db_data +
2246 (db->db_blkid & ((1ULL << epbs) - 1));
2252 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2254 dmu_buf_impl_t *db = dr->dr_dbuf;
2258 ASSERT(dmu_tx_is_syncing(tx));
2260 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2262 mutex_enter(&db->db_mtx);
2264 ASSERT(db->db_level > 0);
2267 /* Read the block if it hasn't been read yet. */
2268 if (db->db_buf == NULL) {
2269 mutex_exit(&db->db_mtx);
2270 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
2271 mutex_enter(&db->db_mtx);
2273 ASSERT3U(db->db_state, ==, DB_CACHED);
2274 ASSERT(db->db_buf != NULL);
2278 /* Indirect block size must match what the dnode thinks it is. */
2279 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2280 dbuf_check_blkptr(dn, db);
2283 /* Provide the pending dirty record to child dbufs */
2284 db->db_data_pending = dr;
2286 mutex_exit(&db->db_mtx);
2287 dbuf_write(dr, db->db_buf, tx);
2290 mutex_enter(&dr->dt.di.dr_mtx);
2291 dbuf_sync_list(&dr->dt.di.dr_children, tx);
2292 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2293 mutex_exit(&dr->dt.di.dr_mtx);
2298 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2300 arc_buf_t **datap = &dr->dt.dl.dr_data;
2301 dmu_buf_impl_t *db = dr->dr_dbuf;
2304 uint64_t txg = tx->tx_txg;
2306 ASSERT(dmu_tx_is_syncing(tx));
2308 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2310 mutex_enter(&db->db_mtx);
2312 * To be synced, we must be dirtied. But we
2313 * might have been freed after the dirty.
2315 if (db->db_state == DB_UNCACHED) {
2316 /* This buffer has been freed since it was dirtied */
2317 ASSERT(db->db.db_data == NULL);
2318 } else if (db->db_state == DB_FILL) {
2319 /* This buffer was freed and is now being re-filled */
2320 ASSERT(db->db.db_data != dr->dt.dl.dr_data);
2322 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL);
2329 if (db->db_blkid == DMU_SPILL_BLKID) {
2330 mutex_enter(&dn->dn_mtx);
2331 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR;
2332 mutex_exit(&dn->dn_mtx);
2336 * If this is a bonus buffer, simply copy the bonus data into the
2337 * dnode. It will be written out when the dnode is synced (and it
2338 * will be synced, since it must have been dirty for dbuf_sync to
2341 if (db->db_blkid == DMU_BONUS_BLKID) {
2342 dbuf_dirty_record_t **drp;
2344 ASSERT(*datap != NULL);
2345 ASSERT0(db->db_level);
2346 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
2347 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
2350 if (*datap != db->db.db_data) {
2351 zio_buf_free(*datap, DN_MAX_BONUSLEN);
2352 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
2354 db->db_data_pending = NULL;
2355 drp = &db->db_last_dirty;
2357 drp = &(*drp)->dr_next;
2358 ASSERT(dr->dr_next == NULL);
2359 ASSERT(dr->dr_dbuf == db);
2361 if (dr->dr_dbuf->db_level != 0) {
2362 list_destroy(&dr->dt.di.dr_children);
2363 mutex_destroy(&dr->dt.di.dr_mtx);
2365 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2366 ASSERT(db->db_dirtycnt > 0);
2367 db->db_dirtycnt -= 1;
2368 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2375 * This function may have dropped the db_mtx lock allowing a dmu_sync
2376 * operation to sneak in. As a result, we need to ensure that we
2377 * don't check the dr_override_state until we have returned from
2378 * dbuf_check_blkptr.
2380 dbuf_check_blkptr(dn, db);
2383 * If this buffer is in the middle of an immediate write,
2384 * wait for the synchronous IO to complete.
2386 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
2387 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
2388 cv_wait(&db->db_changed, &db->db_mtx);
2389 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
2392 if (db->db_state != DB_NOFILL &&
2393 dn->dn_object != DMU_META_DNODE_OBJECT &&
2394 refcount_count(&db->db_holds) > 1 &&
2395 dr->dt.dl.dr_override_state != DR_OVERRIDDEN &&
2396 *datap == db->db_buf) {
2398 * If this buffer is currently "in use" (i.e., there
2399 * are active holds and db_data still references it),
2400 * then make a copy before we start the write so that
2401 * any modifications from the open txg will not leak
2404 * NOTE: this copy does not need to be made for
2405 * objects only modified in the syncing context (e.g.
2406 * DNONE_DNODE blocks).
2408 int blksz = arc_buf_size(*datap);
2409 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2410 *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
2411 bcopy(db->db.db_data, (*datap)->b_data, blksz);
2413 db->db_data_pending = dr;
2415 mutex_exit(&db->db_mtx);
2417 dbuf_write(dr, *datap, tx);
2419 ASSERT(!list_link_active(&dr->dr_dirty_node));
2420 if (dn->dn_object == DMU_META_DNODE_OBJECT) {
2421 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr);
2425 * Although zio_nowait() does not "wait for an IO", it does
2426 * initiate the IO. If this is an empty write it seems plausible
2427 * that the IO could actually be completed before the nowait
2428 * returns. We need to DB_DNODE_EXIT() first in case
2429 * zio_nowait() invalidates the dbuf.
2432 zio_nowait(dr->dr_zio);
2437 dbuf_sync_list(list_t *list, dmu_tx_t *tx)
2439 dbuf_dirty_record_t *dr;
2441 while (dr = list_head(list)) {
2442 if (dr->dr_zio != NULL) {
2444 * If we find an already initialized zio then we
2445 * are processing the meta-dnode, and we have finished.
2446 * The dbufs for all dnodes are put back on the list
2447 * during processing, so that we can zio_wait()
2448 * these IOs after initiating all child IOs.
2450 ASSERT3U(dr->dr_dbuf->db.db_object, ==,
2451 DMU_META_DNODE_OBJECT);
2454 list_remove(list, dr);
2455 if (dr->dr_dbuf->db_level > 0)
2456 dbuf_sync_indirect(dr, tx);
2458 dbuf_sync_leaf(dr, tx);
2464 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
2466 dmu_buf_impl_t *db = vdb;
2468 blkptr_t *bp = zio->io_bp;
2469 blkptr_t *bp_orig = &zio->io_bp_orig;
2470 spa_t *spa = zio->io_spa;
2475 ASSERT(db->db_blkptr == bp);
2479 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig);
2480 dnode_diduse_space(dn, delta - zio->io_prev_space_delta);
2481 zio->io_prev_space_delta = delta;
2483 if (BP_IS_HOLE(bp)) {
2484 ASSERT(bp->blk_fill == 0);
2489 ASSERT((db->db_blkid != DMU_SPILL_BLKID &&
2490 BP_GET_TYPE(bp) == dn->dn_type) ||
2491 (db->db_blkid == DMU_SPILL_BLKID &&
2492 BP_GET_TYPE(bp) == dn->dn_bonustype));
2493 ASSERT(BP_GET_LEVEL(bp) == db->db_level);
2495 mutex_enter(&db->db_mtx);
2498 if (db->db_blkid == DMU_SPILL_BLKID) {
2499 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2500 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2501 db->db_blkptr == &dn->dn_phys->dn_spill);
2505 if (db->db_level == 0) {
2506 mutex_enter(&dn->dn_mtx);
2507 if (db->db_blkid > dn->dn_phys->dn_maxblkid &&
2508 db->db_blkid != DMU_SPILL_BLKID)
2509 dn->dn_phys->dn_maxblkid = db->db_blkid;
2510 mutex_exit(&dn->dn_mtx);
2512 if (dn->dn_type == DMU_OT_DNODE) {
2513 dnode_phys_t *dnp = db->db.db_data;
2514 for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
2516 if (dnp->dn_type != DMU_OT_NONE)
2523 blkptr_t *ibp = db->db.db_data;
2524 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2525 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
2526 if (BP_IS_HOLE(ibp))
2528 fill += ibp->blk_fill;
2533 bp->blk_fill = fill;
2535 mutex_exit(&db->db_mtx);
2539 * The SPA will call this callback several times for each zio - once
2540 * for every physical child i/o (zio->io_phys_children times). This
2541 * allows the DMU to monitor the progress of each logical i/o. For example,
2542 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z
2543 * block. There may be a long delay before all copies/fragments are completed,
2544 * so this callback allows us to retire dirty space gradually, as the physical
2549 dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg)
2551 dmu_buf_impl_t *db = arg;
2552 objset_t *os = db->db_objset;
2553 dsl_pool_t *dp = dmu_objset_pool(os);
2554 dbuf_dirty_record_t *dr;
2557 dr = db->db_data_pending;
2558 ASSERT3U(dr->dr_txg, ==, zio->io_txg);
2561 * The callback will be called io_phys_children times. Retire one
2562 * portion of our dirty space each time we are called. Any rounding
2563 * error will be cleaned up by dsl_pool_sync()'s call to
2564 * dsl_pool_undirty_space().
2566 delta = dr->dr_accounted / zio->io_phys_children;
2567 dsl_pool_undirty_space(dp, delta, zio->io_txg);
2572 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
2574 dmu_buf_impl_t *db = vdb;
2575 blkptr_t *bp = zio->io_bp;
2576 blkptr_t *bp_orig = &zio->io_bp_orig;
2577 uint64_t txg = zio->io_txg;
2578 dbuf_dirty_record_t **drp, *dr;
2580 ASSERT0(zio->io_error);
2581 ASSERT(db->db_blkptr == bp);
2584 * For nopwrites and rewrites we ensure that the bp matches our
2585 * original and bypass all the accounting.
2587 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) {
2588 ASSERT(BP_EQUAL(bp, bp_orig));
2594 DB_GET_OBJSET(&os, db);
2595 ds = os->os_dsl_dataset;
2598 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
2599 dsl_dataset_block_born(ds, bp, tx);
2602 mutex_enter(&db->db_mtx);
2606 drp = &db->db_last_dirty;
2607 while ((dr = *drp) != db->db_data_pending)
2609 ASSERT(!list_link_active(&dr->dr_dirty_node));
2610 ASSERT(dr->dr_txg == txg);
2611 ASSERT(dr->dr_dbuf == db);
2612 ASSERT(dr->dr_next == NULL);
2616 if (db->db_blkid == DMU_SPILL_BLKID) {
2621 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2622 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2623 db->db_blkptr == &dn->dn_phys->dn_spill);
2628 if (db->db_level == 0) {
2629 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
2630 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
2631 if (db->db_state != DB_NOFILL) {
2632 if (dr->dt.dl.dr_data != db->db_buf)
2633 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
2635 else if (!arc_released(db->db_buf))
2636 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2643 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2644 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2645 if (!BP_IS_HOLE(db->db_blkptr)) {
2647 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2648 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
2650 ASSERT3U(dn->dn_phys->dn_maxblkid
2651 >> (db->db_level * epbs), >=, db->db_blkid);
2652 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2655 mutex_destroy(&dr->dt.di.dr_mtx);
2656 list_destroy(&dr->dt.di.dr_children);
2658 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2660 cv_broadcast(&db->db_changed);
2661 ASSERT(db->db_dirtycnt > 0);
2662 db->db_dirtycnt -= 1;
2663 db->db_data_pending = NULL;
2665 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2669 dbuf_write_nofill_ready(zio_t *zio)
2671 dbuf_write_ready(zio, NULL, zio->io_private);
2675 dbuf_write_nofill_done(zio_t *zio)
2677 dbuf_write_done(zio, NULL, zio->io_private);
2681 dbuf_write_override_ready(zio_t *zio)
2683 dbuf_dirty_record_t *dr = zio->io_private;
2684 dmu_buf_impl_t *db = dr->dr_dbuf;
2686 dbuf_write_ready(zio, NULL, db);
2690 dbuf_write_override_done(zio_t *zio)
2692 dbuf_dirty_record_t *dr = zio->io_private;
2693 dmu_buf_impl_t *db = dr->dr_dbuf;
2694 blkptr_t *obp = &dr->dt.dl.dr_overridden_by;
2696 mutex_enter(&db->db_mtx);
2697 if (!BP_EQUAL(zio->io_bp, obp)) {
2698 if (!BP_IS_HOLE(obp))
2699 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp);
2700 arc_release(dr->dt.dl.dr_data, db);
2702 mutex_exit(&db->db_mtx);
2704 dbuf_write_done(zio, NULL, db);
2707 /* Issue I/O to commit a dirty buffer to disk. */
2709 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
2711 dmu_buf_impl_t *db = dr->dr_dbuf;
2714 dmu_buf_impl_t *parent = db->db_parent;
2715 uint64_t txg = tx->tx_txg;
2725 if (db->db_state != DB_NOFILL) {
2726 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) {
2728 * Private object buffers are released here rather
2729 * than in dbuf_dirty() since they are only modified
2730 * in the syncing context and we don't want the
2731 * overhead of making multiple copies of the data.
2733 if (BP_IS_HOLE(db->db_blkptr)) {
2736 dbuf_release_bp(db);
2741 if (parent != dn->dn_dbuf) {
2742 /* Our parent is an indirect block. */
2743 /* We have a dirty parent that has been scheduled for write. */
2744 ASSERT(parent && parent->db_data_pending);
2745 /* Our parent's buffer is one level closer to the dnode. */
2746 ASSERT(db->db_level == parent->db_level-1);
2748 * We're about to modify our parent's db_data by modifying
2749 * our block pointer, so the parent must be released.
2751 ASSERT(arc_released(parent->db_buf));
2752 zio = parent->db_data_pending->dr_zio;
2754 /* Our parent is the dnode itself. */
2755 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 &&
2756 db->db_blkid != DMU_SPILL_BLKID) ||
2757 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0));
2758 if (db->db_blkid != DMU_SPILL_BLKID)
2759 ASSERT3P(db->db_blkptr, ==,
2760 &dn->dn_phys->dn_blkptr[db->db_blkid]);
2764 ASSERT(db->db_level == 0 || data == db->db_buf);
2765 ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
2768 SET_BOOKMARK(&zb, os->os_dsl_dataset ?
2769 os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
2770 db->db.db_object, db->db_level, db->db_blkid);
2772 if (db->db_blkid == DMU_SPILL_BLKID)
2774 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0;
2776 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp);
2779 if (db->db_level == 0 && dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
2780 ASSERT(db->db_state != DB_NOFILL);
2781 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2782 db->db_blkptr, data->b_data, arc_buf_size(data), &zp,
2783 dbuf_write_override_ready, NULL, dbuf_write_override_done,
2784 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2785 mutex_enter(&db->db_mtx);
2786 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
2787 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by,
2788 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite);
2789 mutex_exit(&db->db_mtx);
2790 } else if (db->db_state == DB_NOFILL) {
2791 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF ||
2792 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY);
2793 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2794 db->db_blkptr, NULL, db->db.db_size, &zp,
2795 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db,
2796 ZIO_PRIORITY_ASYNC_WRITE,
2797 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb);
2799 ASSERT(arc_released(data));
2800 dr->dr_zio = arc_write(zio, os->os_spa, txg,
2801 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db),
2802 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready,
2803 dbuf_write_physdone, dbuf_write_done, db,
2804 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);