dbuf.c revision 288576
1/* 2 * CDDL HEADER START 3 * 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. 7 * 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. 12 * 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] 18 * 19 * CDDL HEADER END 20 */ 21/* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 24 * Copyright (c) 2012, 2015 by Delphix. All rights reserved. 25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved. 26 * Copyright (c) 2013, Joyent, Inc. All rights reserved. 27 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. 28 */ 29 30#include <sys/zfs_context.h> 31#include <sys/dmu.h> 32#include <sys/dmu_send.h> 33#include <sys/dmu_impl.h> 34#include <sys/dbuf.h> 35#include <sys/dmu_objset.h> 36#include <sys/dsl_dataset.h> 37#include <sys/dsl_dir.h> 38#include <sys/dmu_tx.h> 39#include <sys/spa.h> 40#include <sys/zio.h> 41#include <sys/dmu_zfetch.h> 42#include <sys/sa.h> 43#include <sys/sa_impl.h> 44#include <sys/zfeature.h> 45#include <sys/blkptr.h> 46#include <sys/range_tree.h> 47 48/* 49 * Number of times that zfs_free_range() took the slow path while doing 50 * a zfs receive. A nonzero value indicates a potential performance problem. 51 */ 52uint64_t zfs_free_range_recv_miss; 53 54static void dbuf_destroy(dmu_buf_impl_t *db); 55static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 56static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx); 57 58/* 59 * Global data structures and functions for the dbuf cache. 60 */ 61static kmem_cache_t *dbuf_cache; 62static taskq_t *dbu_evict_taskq; 63 64/* ARGSUSED */ 65static int 66dbuf_cons(void *vdb, void *unused, int kmflag) 67{ 68 dmu_buf_impl_t *db = vdb; 69 bzero(db, sizeof (dmu_buf_impl_t)); 70 71 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL); 72 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL); 73 refcount_create(&db->db_holds); 74 75 return (0); 76} 77 78/* ARGSUSED */ 79static void 80dbuf_dest(void *vdb, void *unused) 81{ 82 dmu_buf_impl_t *db = vdb; 83 mutex_destroy(&db->db_mtx); 84 cv_destroy(&db->db_changed); 85 refcount_destroy(&db->db_holds); 86} 87 88/* 89 * dbuf hash table routines 90 */ 91static dbuf_hash_table_t dbuf_hash_table; 92 93static uint64_t dbuf_hash_count; 94 95static uint64_t 96dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid) 97{ 98 uintptr_t osv = (uintptr_t)os; 99 uint64_t crc = -1ULL; 100 101 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); 102 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF]; 103 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF]; 104 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF]; 105 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF]; 106 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF]; 107 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF]; 108 109 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16); 110 111 return (crc); 112} 113 114#define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid); 115 116#define DBUF_EQUAL(dbuf, os, obj, level, blkid) \ 117 ((dbuf)->db.db_object == (obj) && \ 118 (dbuf)->db_objset == (os) && \ 119 (dbuf)->db_level == (level) && \ 120 (dbuf)->db_blkid == (blkid)) 121 122dmu_buf_impl_t * 123dbuf_find(objset_t *os, uint64_t obj, uint8_t level, uint64_t blkid) 124{ 125 dbuf_hash_table_t *h = &dbuf_hash_table; 126 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 127 uint64_t idx = hv & h->hash_table_mask; 128 dmu_buf_impl_t *db; 129 130 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 131 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) { 132 if (DBUF_EQUAL(db, os, obj, level, blkid)) { 133 mutex_enter(&db->db_mtx); 134 if (db->db_state != DB_EVICTING) { 135 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 136 return (db); 137 } 138 mutex_exit(&db->db_mtx); 139 } 140 } 141 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 142 return (NULL); 143} 144 145static dmu_buf_impl_t * 146dbuf_find_bonus(objset_t *os, uint64_t object) 147{ 148 dnode_t *dn; 149 dmu_buf_impl_t *db = NULL; 150 151 if (dnode_hold(os, object, FTAG, &dn) == 0) { 152 rw_enter(&dn->dn_struct_rwlock, RW_READER); 153 if (dn->dn_bonus != NULL) { 154 db = dn->dn_bonus; 155 mutex_enter(&db->db_mtx); 156 } 157 rw_exit(&dn->dn_struct_rwlock); 158 dnode_rele(dn, FTAG); 159 } 160 return (db); 161} 162 163/* 164 * Insert an entry into the hash table. If there is already an element 165 * equal to elem in the hash table, then the already existing element 166 * will be returned and the new element will not be inserted. 167 * Otherwise returns NULL. 168 */ 169static dmu_buf_impl_t * 170dbuf_hash_insert(dmu_buf_impl_t *db) 171{ 172 dbuf_hash_table_t *h = &dbuf_hash_table; 173 objset_t *os = db->db_objset; 174 uint64_t obj = db->db.db_object; 175 int level = db->db_level; 176 uint64_t blkid = db->db_blkid; 177 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 178 uint64_t idx = hv & h->hash_table_mask; 179 dmu_buf_impl_t *dbf; 180 181 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 182 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) { 183 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) { 184 mutex_enter(&dbf->db_mtx); 185 if (dbf->db_state != DB_EVICTING) { 186 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 187 return (dbf); 188 } 189 mutex_exit(&dbf->db_mtx); 190 } 191 } 192 193 mutex_enter(&db->db_mtx); 194 db->db_hash_next = h->hash_table[idx]; 195 h->hash_table[idx] = db; 196 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 197 atomic_inc_64(&dbuf_hash_count); 198 199 return (NULL); 200} 201 202/* 203 * Remove an entry from the hash table. It must be in the EVICTING state. 204 */ 205static void 206dbuf_hash_remove(dmu_buf_impl_t *db) 207{ 208 dbuf_hash_table_t *h = &dbuf_hash_table; 209 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object, 210 db->db_level, db->db_blkid); 211 uint64_t idx = hv & h->hash_table_mask; 212 dmu_buf_impl_t *dbf, **dbp; 213 214 /* 215 * We musn't hold db_mtx to maintain lock ordering: 216 * DBUF_HASH_MUTEX > db_mtx. 217 */ 218 ASSERT(refcount_is_zero(&db->db_holds)); 219 ASSERT(db->db_state == DB_EVICTING); 220 ASSERT(!MUTEX_HELD(&db->db_mtx)); 221 222 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 223 dbp = &h->hash_table[idx]; 224 while ((dbf = *dbp) != db) { 225 dbp = &dbf->db_hash_next; 226 ASSERT(dbf != NULL); 227 } 228 *dbp = db->db_hash_next; 229 db->db_hash_next = NULL; 230 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 231 atomic_dec_64(&dbuf_hash_count); 232} 233 234static arc_evict_func_t dbuf_do_evict; 235 236typedef enum { 237 DBVU_EVICTING, 238 DBVU_NOT_EVICTING 239} dbvu_verify_type_t; 240 241static void 242dbuf_verify_user(dmu_buf_impl_t *db, dbvu_verify_type_t verify_type) 243{ 244#ifdef ZFS_DEBUG 245 int64_t holds; 246 247 if (db->db_user == NULL) 248 return; 249 250 /* Only data blocks support the attachment of user data. */ 251 ASSERT(db->db_level == 0); 252 253 /* Clients must resolve a dbuf before attaching user data. */ 254 ASSERT(db->db.db_data != NULL); 255 ASSERT3U(db->db_state, ==, DB_CACHED); 256 257 holds = refcount_count(&db->db_holds); 258 if (verify_type == DBVU_EVICTING) { 259 /* 260 * Immediate eviction occurs when holds == dirtycnt. 261 * For normal eviction buffers, holds is zero on 262 * eviction, except when dbuf_fix_old_data() calls 263 * dbuf_clear_data(). However, the hold count can grow 264 * during eviction even though db_mtx is held (see 265 * dmu_bonus_hold() for an example), so we can only 266 * test the generic invariant that holds >= dirtycnt. 267 */ 268 ASSERT3U(holds, >=, db->db_dirtycnt); 269 } else { 270 if (db->db_immediate_evict == TRUE) 271 ASSERT3U(holds, >=, db->db_dirtycnt); 272 else 273 ASSERT3U(holds, >, 0); 274 } 275#endif 276} 277 278static void 279dbuf_evict_user(dmu_buf_impl_t *db) 280{ 281 dmu_buf_user_t *dbu = db->db_user; 282 283 ASSERT(MUTEX_HELD(&db->db_mtx)); 284 285 if (dbu == NULL) 286 return; 287 288 dbuf_verify_user(db, DBVU_EVICTING); 289 db->db_user = NULL; 290 291#ifdef ZFS_DEBUG 292 if (dbu->dbu_clear_on_evict_dbufp != NULL) 293 *dbu->dbu_clear_on_evict_dbufp = NULL; 294#endif 295 296 /* 297 * Invoke the callback from a taskq to avoid lock order reversals 298 * and limit stack depth. 299 */ 300 taskq_dispatch_ent(dbu_evict_taskq, dbu->dbu_evict_func, dbu, 0, 301 &dbu->dbu_tqent); 302} 303 304boolean_t 305dbuf_is_metadata(dmu_buf_impl_t *db) 306{ 307 if (db->db_level > 0) { 308 return (B_TRUE); 309 } else { 310 boolean_t is_metadata; 311 312 DB_DNODE_ENTER(db); 313 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type); 314 DB_DNODE_EXIT(db); 315 316 return (is_metadata); 317 } 318} 319 320void 321dbuf_evict(dmu_buf_impl_t *db) 322{ 323 ASSERT(MUTEX_HELD(&db->db_mtx)); 324 ASSERT(db->db_buf == NULL); 325 ASSERT(db->db_data_pending == NULL); 326 327 dbuf_clear(db); 328 dbuf_destroy(db); 329} 330 331void 332dbuf_init(void) 333{ 334 uint64_t hsize = 1ULL << 16; 335 dbuf_hash_table_t *h = &dbuf_hash_table; 336 int i; 337 338 /* 339 * The hash table is big enough to fill all of physical memory 340 * with an average 4K block size. The table will take up 341 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers). 342 */ 343 while (hsize * 4096 < (uint64_t)physmem * PAGESIZE) 344 hsize <<= 1; 345 346retry: 347 h->hash_table_mask = hsize - 1; 348 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP); 349 if (h->hash_table == NULL) { 350 /* XXX - we should really return an error instead of assert */ 351 ASSERT(hsize > (1ULL << 10)); 352 hsize >>= 1; 353 goto retry; 354 } 355 356 dbuf_cache = kmem_cache_create("dmu_buf_impl_t", 357 sizeof (dmu_buf_impl_t), 358 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0); 359 360 for (i = 0; i < DBUF_MUTEXES; i++) 361 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL); 362 363 /* 364 * All entries are queued via taskq_dispatch_ent(), so min/maxalloc 365 * configuration is not required. 366 */ 367 dbu_evict_taskq = taskq_create("dbu_evict", 1, minclsyspri, 0, 0, 0); 368} 369 370void 371dbuf_fini(void) 372{ 373 dbuf_hash_table_t *h = &dbuf_hash_table; 374 int i; 375 376 for (i = 0; i < DBUF_MUTEXES; i++) 377 mutex_destroy(&h->hash_mutexes[i]); 378 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *)); 379 kmem_cache_destroy(dbuf_cache); 380 taskq_destroy(dbu_evict_taskq); 381} 382 383/* 384 * Other stuff. 385 */ 386 387#ifdef ZFS_DEBUG 388static void 389dbuf_verify(dmu_buf_impl_t *db) 390{ 391 dnode_t *dn; 392 dbuf_dirty_record_t *dr; 393 394 ASSERT(MUTEX_HELD(&db->db_mtx)); 395 396 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY)) 397 return; 398 399 ASSERT(db->db_objset != NULL); 400 DB_DNODE_ENTER(db); 401 dn = DB_DNODE(db); 402 if (dn == NULL) { 403 ASSERT(db->db_parent == NULL); 404 ASSERT(db->db_blkptr == NULL); 405 } else { 406 ASSERT3U(db->db.db_object, ==, dn->dn_object); 407 ASSERT3P(db->db_objset, ==, dn->dn_objset); 408 ASSERT3U(db->db_level, <, dn->dn_nlevels); 409 ASSERT(db->db_blkid == DMU_BONUS_BLKID || 410 db->db_blkid == DMU_SPILL_BLKID || 411 !avl_is_empty(&dn->dn_dbufs)); 412 } 413 if (db->db_blkid == DMU_BONUS_BLKID) { 414 ASSERT(dn != NULL); 415 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 416 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID); 417 } else if (db->db_blkid == DMU_SPILL_BLKID) { 418 ASSERT(dn != NULL); 419 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 420 ASSERT0(db->db.db_offset); 421 } else { 422 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size); 423 } 424 425 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next) 426 ASSERT(dr->dr_dbuf == db); 427 428 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next) 429 ASSERT(dr->dr_dbuf == db); 430 431 /* 432 * We can't assert that db_size matches dn_datablksz because it 433 * can be momentarily different when another thread is doing 434 * dnode_set_blksz(). 435 */ 436 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) { 437 dr = db->db_data_pending; 438 /* 439 * It should only be modified in syncing context, so 440 * make sure we only have one copy of the data. 441 */ 442 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf); 443 } 444 445 /* verify db->db_blkptr */ 446 if (db->db_blkptr) { 447 if (db->db_parent == dn->dn_dbuf) { 448 /* db is pointed to by the dnode */ 449 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */ 450 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object)) 451 ASSERT(db->db_parent == NULL); 452 else 453 ASSERT(db->db_parent != NULL); 454 if (db->db_blkid != DMU_SPILL_BLKID) 455 ASSERT3P(db->db_blkptr, ==, 456 &dn->dn_phys->dn_blkptr[db->db_blkid]); 457 } else { 458 /* db is pointed to by an indirect block */ 459 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT; 460 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1); 461 ASSERT3U(db->db_parent->db.db_object, ==, 462 db->db.db_object); 463 /* 464 * dnode_grow_indblksz() can make this fail if we don't 465 * have the struct_rwlock. XXX indblksz no longer 466 * grows. safe to do this now? 467 */ 468 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 469 ASSERT3P(db->db_blkptr, ==, 470 ((blkptr_t *)db->db_parent->db.db_data + 471 db->db_blkid % epb)); 472 } 473 } 474 } 475 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) && 476 (db->db_buf == NULL || db->db_buf->b_data) && 477 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID && 478 db->db_state != DB_FILL && !dn->dn_free_txg) { 479 /* 480 * If the blkptr isn't set but they have nonzero data, 481 * it had better be dirty, otherwise we'll lose that 482 * data when we evict this buffer. 483 */ 484 if (db->db_dirtycnt == 0) { 485 uint64_t *buf = db->db.db_data; 486 int i; 487 488 for (i = 0; i < db->db.db_size >> 3; i++) { 489 ASSERT(buf[i] == 0); 490 } 491 } 492 } 493 DB_DNODE_EXIT(db); 494} 495#endif 496 497static void 498dbuf_clear_data(dmu_buf_impl_t *db) 499{ 500 ASSERT(MUTEX_HELD(&db->db_mtx)); 501 dbuf_evict_user(db); 502 db->db_buf = NULL; 503 db->db.db_data = NULL; 504 if (db->db_state != DB_NOFILL) 505 db->db_state = DB_UNCACHED; 506} 507 508static void 509dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf) 510{ 511 ASSERT(MUTEX_HELD(&db->db_mtx)); 512 ASSERT(buf != NULL); 513 514 db->db_buf = buf; 515 ASSERT(buf->b_data != NULL); 516 db->db.db_data = buf->b_data; 517 if (!arc_released(buf)) 518 arc_set_callback(buf, dbuf_do_evict, db); 519} 520 521/* 522 * Loan out an arc_buf for read. Return the loaned arc_buf. 523 */ 524arc_buf_t * 525dbuf_loan_arcbuf(dmu_buf_impl_t *db) 526{ 527 arc_buf_t *abuf; 528 529 mutex_enter(&db->db_mtx); 530 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) { 531 int blksz = db->db.db_size; 532 spa_t *spa = db->db_objset->os_spa; 533 534 mutex_exit(&db->db_mtx); 535 abuf = arc_loan_buf(spa, blksz); 536 bcopy(db->db.db_data, abuf->b_data, blksz); 537 } else { 538 abuf = db->db_buf; 539 arc_loan_inuse_buf(abuf, db); 540 dbuf_clear_data(db); 541 mutex_exit(&db->db_mtx); 542 } 543 return (abuf); 544} 545 546/* 547 * Calculate which level n block references the data at the level 0 offset 548 * provided. 549 */ 550uint64_t 551dbuf_whichblock(dnode_t *dn, int64_t level, uint64_t offset) 552{ 553 if (dn->dn_datablkshift != 0 && dn->dn_indblkshift != 0) { 554 /* 555 * The level n blkid is equal to the level 0 blkid divided by 556 * the number of level 0s in a level n block. 557 * 558 * The level 0 blkid is offset >> datablkshift = 559 * offset / 2^datablkshift. 560 * 561 * The number of level 0s in a level n is the number of block 562 * pointers in an indirect block, raised to the power of level. 563 * This is 2^(indblkshift - SPA_BLKPTRSHIFT)^level = 564 * 2^(level*(indblkshift - SPA_BLKPTRSHIFT)). 565 * 566 * Thus, the level n blkid is: offset / 567 * ((2^datablkshift)*(2^(level*(indblkshift - SPA_BLKPTRSHIFT))) 568 * = offset / 2^(datablkshift + level * 569 * (indblkshift - SPA_BLKPTRSHIFT)) 570 * = offset >> (datablkshift + level * 571 * (indblkshift - SPA_BLKPTRSHIFT)) 572 */ 573 return (offset >> (dn->dn_datablkshift + level * 574 (dn->dn_indblkshift - SPA_BLKPTRSHIFT))); 575 } else { 576 ASSERT3U(offset, <, dn->dn_datablksz); 577 return (0); 578 } 579} 580 581static void 582dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb) 583{ 584 dmu_buf_impl_t *db = vdb; 585 586 mutex_enter(&db->db_mtx); 587 ASSERT3U(db->db_state, ==, DB_READ); 588 /* 589 * All reads are synchronous, so we must have a hold on the dbuf 590 */ 591 ASSERT(refcount_count(&db->db_holds) > 0); 592 ASSERT(db->db_buf == NULL); 593 ASSERT(db->db.db_data == NULL); 594 if (db->db_level == 0 && db->db_freed_in_flight) { 595 /* we were freed in flight; disregard any error */ 596 arc_release(buf, db); 597 bzero(buf->b_data, db->db.db_size); 598 arc_buf_freeze(buf); 599 db->db_freed_in_flight = FALSE; 600 dbuf_set_data(db, buf); 601 db->db_state = DB_CACHED; 602 } else if (zio == NULL || zio->io_error == 0) { 603 dbuf_set_data(db, buf); 604 db->db_state = DB_CACHED; 605 } else { 606 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 607 ASSERT3P(db->db_buf, ==, NULL); 608 VERIFY(arc_buf_remove_ref(buf, db)); 609 db->db_state = DB_UNCACHED; 610 } 611 cv_broadcast(&db->db_changed); 612 dbuf_rele_and_unlock(db, NULL); 613} 614 615static void 616dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags) 617{ 618 dnode_t *dn; 619 zbookmark_phys_t zb; 620 arc_flags_t aflags = ARC_FLAG_NOWAIT; 621 622 DB_DNODE_ENTER(db); 623 dn = DB_DNODE(db); 624 ASSERT(!refcount_is_zero(&db->db_holds)); 625 /* We need the struct_rwlock to prevent db_blkptr from changing. */ 626 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 627 ASSERT(MUTEX_HELD(&db->db_mtx)); 628 ASSERT(db->db_state == DB_UNCACHED); 629 ASSERT(db->db_buf == NULL); 630 631 if (db->db_blkid == DMU_BONUS_BLKID) { 632 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen); 633 634 ASSERT3U(bonuslen, <=, db->db.db_size); 635 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN); 636 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 637 if (bonuslen < DN_MAX_BONUSLEN) 638 bzero(db->db.db_data, DN_MAX_BONUSLEN); 639 if (bonuslen) 640 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen); 641 DB_DNODE_EXIT(db); 642 db->db_state = DB_CACHED; 643 mutex_exit(&db->db_mtx); 644 return; 645 } 646 647 /* 648 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync() 649 * processes the delete record and clears the bp while we are waiting 650 * for the dn_mtx (resulting in a "no" from block_freed). 651 */ 652 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) || 653 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) || 654 BP_IS_HOLE(db->db_blkptr)))) { 655 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 656 657 DB_DNODE_EXIT(db); 658 dbuf_set_data(db, arc_buf_alloc(db->db_objset->os_spa, 659 db->db.db_size, db, type)); 660 bzero(db->db.db_data, db->db.db_size); 661 db->db_state = DB_CACHED; 662 *flags |= DB_RF_CACHED; 663 mutex_exit(&db->db_mtx); 664 return; 665 } 666 667 DB_DNODE_EXIT(db); 668 669 db->db_state = DB_READ; 670 mutex_exit(&db->db_mtx); 671 672 if (DBUF_IS_L2CACHEABLE(db)) 673 aflags |= ARC_FLAG_L2CACHE; 674 if (DBUF_IS_L2COMPRESSIBLE(db)) 675 aflags |= ARC_FLAG_L2COMPRESS; 676 677 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ? 678 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET, 679 db->db.db_object, db->db_level, db->db_blkid); 680 681 dbuf_add_ref(db, NULL); 682 683 (void) arc_read(zio, db->db_objset->os_spa, db->db_blkptr, 684 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ, 685 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED, 686 &aflags, &zb); 687 if (aflags & ARC_FLAG_CACHED) 688 *flags |= DB_RF_CACHED; 689} 690 691int 692dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) 693{ 694 int err = 0; 695 boolean_t havepzio = (zio != NULL); 696 boolean_t prefetch; 697 dnode_t *dn; 698 699 /* 700 * We don't have to hold the mutex to check db_state because it 701 * can't be freed while we have a hold on the buffer. 702 */ 703 ASSERT(!refcount_is_zero(&db->db_holds)); 704 705 if (db->db_state == DB_NOFILL) 706 return (SET_ERROR(EIO)); 707 708 DB_DNODE_ENTER(db); 709 dn = DB_DNODE(db); 710 if ((flags & DB_RF_HAVESTRUCT) == 0) 711 rw_enter(&dn->dn_struct_rwlock, RW_READER); 712 713 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 714 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL && 715 DBUF_IS_CACHEABLE(db); 716 717 mutex_enter(&db->db_mtx); 718 if (db->db_state == DB_CACHED) { 719 mutex_exit(&db->db_mtx); 720 if (prefetch) 721 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 722 db->db.db_size, TRUE); 723 if ((flags & DB_RF_HAVESTRUCT) == 0) 724 rw_exit(&dn->dn_struct_rwlock); 725 DB_DNODE_EXIT(db); 726 } else if (db->db_state == DB_UNCACHED) { 727 spa_t *spa = dn->dn_objset->os_spa; 728 729 if (zio == NULL) 730 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL); 731 dbuf_read_impl(db, zio, &flags); 732 733 /* dbuf_read_impl has dropped db_mtx for us */ 734 735 if (prefetch) 736 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 737 db->db.db_size, flags & DB_RF_CACHED); 738 739 if ((flags & DB_RF_HAVESTRUCT) == 0) 740 rw_exit(&dn->dn_struct_rwlock); 741 DB_DNODE_EXIT(db); 742 743 if (!havepzio) 744 err = zio_wait(zio); 745 } else { 746 /* 747 * Another reader came in while the dbuf was in flight 748 * between UNCACHED and CACHED. Either a writer will finish 749 * writing the buffer (sending the dbuf to CACHED) or the 750 * first reader's request will reach the read_done callback 751 * and send the dbuf to CACHED. Otherwise, a failure 752 * occurred and the dbuf went to UNCACHED. 753 */ 754 mutex_exit(&db->db_mtx); 755 if (prefetch) 756 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 757 db->db.db_size, TRUE); 758 if ((flags & DB_RF_HAVESTRUCT) == 0) 759 rw_exit(&dn->dn_struct_rwlock); 760 DB_DNODE_EXIT(db); 761 762 /* Skip the wait per the caller's request. */ 763 mutex_enter(&db->db_mtx); 764 if ((flags & DB_RF_NEVERWAIT) == 0) { 765 while (db->db_state == DB_READ || 766 db->db_state == DB_FILL) { 767 ASSERT(db->db_state == DB_READ || 768 (flags & DB_RF_HAVESTRUCT) == 0); 769 DTRACE_PROBE2(blocked__read, dmu_buf_impl_t *, 770 db, zio_t *, zio); 771 cv_wait(&db->db_changed, &db->db_mtx); 772 } 773 if (db->db_state == DB_UNCACHED) 774 err = SET_ERROR(EIO); 775 } 776 mutex_exit(&db->db_mtx); 777 } 778 779 ASSERT(err || havepzio || db->db_state == DB_CACHED); 780 return (err); 781} 782 783static void 784dbuf_noread(dmu_buf_impl_t *db) 785{ 786 ASSERT(!refcount_is_zero(&db->db_holds)); 787 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 788 mutex_enter(&db->db_mtx); 789 while (db->db_state == DB_READ || db->db_state == DB_FILL) 790 cv_wait(&db->db_changed, &db->db_mtx); 791 if (db->db_state == DB_UNCACHED) { 792 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 793 spa_t *spa = db->db_objset->os_spa; 794 795 ASSERT(db->db_buf == NULL); 796 ASSERT(db->db.db_data == NULL); 797 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type)); 798 db->db_state = DB_FILL; 799 } else if (db->db_state == DB_NOFILL) { 800 dbuf_clear_data(db); 801 } else { 802 ASSERT3U(db->db_state, ==, DB_CACHED); 803 } 804 mutex_exit(&db->db_mtx); 805} 806 807/* 808 * This is our just-in-time copy function. It makes a copy of 809 * buffers, that have been modified in a previous transaction 810 * group, before we modify them in the current active group. 811 * 812 * This function is used in two places: when we are dirtying a 813 * buffer for the first time in a txg, and when we are freeing 814 * a range in a dnode that includes this buffer. 815 * 816 * Note that when we are called from dbuf_free_range() we do 817 * not put a hold on the buffer, we just traverse the active 818 * dbuf list for the dnode. 819 */ 820static void 821dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg) 822{ 823 dbuf_dirty_record_t *dr = db->db_last_dirty; 824 825 ASSERT(MUTEX_HELD(&db->db_mtx)); 826 ASSERT(db->db.db_data != NULL); 827 ASSERT(db->db_level == 0); 828 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT); 829 830 if (dr == NULL || 831 (dr->dt.dl.dr_data != 832 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf))) 833 return; 834 835 /* 836 * If the last dirty record for this dbuf has not yet synced 837 * and its referencing the dbuf data, either: 838 * reset the reference to point to a new copy, 839 * or (if there a no active holders) 840 * just null out the current db_data pointer. 841 */ 842 ASSERT(dr->dr_txg >= txg - 2); 843 if (db->db_blkid == DMU_BONUS_BLKID) { 844 /* Note that the data bufs here are zio_bufs */ 845 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN); 846 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 847 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN); 848 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) { 849 int size = db->db.db_size; 850 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 851 spa_t *spa = db->db_objset->os_spa; 852 853 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type); 854 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size); 855 } else { 856 dbuf_clear_data(db); 857 } 858} 859 860void 861dbuf_unoverride(dbuf_dirty_record_t *dr) 862{ 863 dmu_buf_impl_t *db = dr->dr_dbuf; 864 blkptr_t *bp = &dr->dt.dl.dr_overridden_by; 865 uint64_t txg = dr->dr_txg; 866 867 ASSERT(MUTEX_HELD(&db->db_mtx)); 868 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC); 869 ASSERT(db->db_level == 0); 870 871 if (db->db_blkid == DMU_BONUS_BLKID || 872 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN) 873 return; 874 875 ASSERT(db->db_data_pending != dr); 876 877 /* free this block */ 878 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite) 879 zio_free(db->db_objset->os_spa, txg, bp); 880 881 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 882 dr->dt.dl.dr_nopwrite = B_FALSE; 883 884 /* 885 * Release the already-written buffer, so we leave it in 886 * a consistent dirty state. Note that all callers are 887 * modifying the buffer, so they will immediately do 888 * another (redundant) arc_release(). Therefore, leave 889 * the buf thawed to save the effort of freezing & 890 * immediately re-thawing it. 891 */ 892 arc_release(dr->dt.dl.dr_data, db); 893} 894 895/* 896 * Evict (if its unreferenced) or clear (if its referenced) any level-0 897 * data blocks in the free range, so that any future readers will find 898 * empty blocks. 899 * 900 * This is a no-op if the dataset is in the middle of an incremental 901 * receive; see comment below for details. 902 */ 903void 904dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, 905 dmu_tx_t *tx) 906{ 907 dmu_buf_impl_t db_search; 908 dmu_buf_impl_t *db, *db_next; 909 uint64_t txg = tx->tx_txg; 910 avl_index_t where; 911 912 if (end_blkid > dn->dn_maxblkid && (end_blkid != DMU_SPILL_BLKID)) 913 end_blkid = dn->dn_maxblkid; 914 dprintf_dnode(dn, "start=%llu end=%llu\n", start_blkid, end_blkid); 915 916 db_search.db_level = 0; 917 db_search.db_blkid = start_blkid; 918 db_search.db_state = DB_SEARCH; 919 920 mutex_enter(&dn->dn_dbufs_mtx); 921 if (start_blkid >= dn->dn_unlisted_l0_blkid) { 922 /* There can't be any dbufs in this range; no need to search. */ 923#ifdef DEBUG 924 db = avl_find(&dn->dn_dbufs, &db_search, &where); 925 ASSERT3P(db, ==, NULL); 926 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 927 ASSERT(db == NULL || db->db_level > 0); 928#endif 929 mutex_exit(&dn->dn_dbufs_mtx); 930 return; 931 } else if (dmu_objset_is_receiving(dn->dn_objset)) { 932 /* 933 * If we are receiving, we expect there to be no dbufs in 934 * the range to be freed, because receive modifies each 935 * block at most once, and in offset order. If this is 936 * not the case, it can lead to performance problems, 937 * so note that we unexpectedly took the slow path. 938 */ 939 atomic_inc_64(&zfs_free_range_recv_miss); 940 } 941 942 db = avl_find(&dn->dn_dbufs, &db_search, &where); 943 ASSERT3P(db, ==, NULL); 944 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 945 946 for (; db != NULL; db = db_next) { 947 db_next = AVL_NEXT(&dn->dn_dbufs, db); 948 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 949 950 if (db->db_level != 0 || db->db_blkid > end_blkid) { 951 break; 952 } 953 ASSERT3U(db->db_blkid, >=, start_blkid); 954 955 /* found a level 0 buffer in the range */ 956 mutex_enter(&db->db_mtx); 957 if (dbuf_undirty(db, tx)) { 958 /* mutex has been dropped and dbuf destroyed */ 959 continue; 960 } 961 962 if (db->db_state == DB_UNCACHED || 963 db->db_state == DB_NOFILL || 964 db->db_state == DB_EVICTING) { 965 ASSERT(db->db.db_data == NULL); 966 mutex_exit(&db->db_mtx); 967 continue; 968 } 969 if (db->db_state == DB_READ || db->db_state == DB_FILL) { 970 /* will be handled in dbuf_read_done or dbuf_rele */ 971 db->db_freed_in_flight = TRUE; 972 mutex_exit(&db->db_mtx); 973 continue; 974 } 975 if (refcount_count(&db->db_holds) == 0) { 976 ASSERT(db->db_buf); 977 dbuf_clear(db); 978 continue; 979 } 980 /* The dbuf is referenced */ 981 982 if (db->db_last_dirty != NULL) { 983 dbuf_dirty_record_t *dr = db->db_last_dirty; 984 985 if (dr->dr_txg == txg) { 986 /* 987 * This buffer is "in-use", re-adjust the file 988 * size to reflect that this buffer may 989 * contain new data when we sync. 990 */ 991 if (db->db_blkid != DMU_SPILL_BLKID && 992 db->db_blkid > dn->dn_maxblkid) 993 dn->dn_maxblkid = db->db_blkid; 994 dbuf_unoverride(dr); 995 } else { 996 /* 997 * This dbuf is not dirty in the open context. 998 * Either uncache it (if its not referenced in 999 * the open context) or reset its contents to 1000 * empty. 1001 */ 1002 dbuf_fix_old_data(db, txg); 1003 } 1004 } 1005 /* clear the contents if its cached */ 1006 if (db->db_state == DB_CACHED) { 1007 ASSERT(db->db.db_data != NULL); 1008 arc_release(db->db_buf, db); 1009 bzero(db->db.db_data, db->db.db_size); 1010 arc_buf_freeze(db->db_buf); 1011 } 1012 1013 mutex_exit(&db->db_mtx); 1014 } 1015 mutex_exit(&dn->dn_dbufs_mtx); 1016} 1017 1018static int 1019dbuf_block_freeable(dmu_buf_impl_t *db) 1020{ 1021 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset; 1022 uint64_t birth_txg = 0; 1023 1024 /* 1025 * We don't need any locking to protect db_blkptr: 1026 * If it's syncing, then db_last_dirty will be set 1027 * so we'll ignore db_blkptr. 1028 * 1029 * This logic ensures that only block births for 1030 * filled blocks are considered. 1031 */ 1032 ASSERT(MUTEX_HELD(&db->db_mtx)); 1033 if (db->db_last_dirty && (db->db_blkptr == NULL || 1034 !BP_IS_HOLE(db->db_blkptr))) { 1035 birth_txg = db->db_last_dirty->dr_txg; 1036 } else if (db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr)) { 1037 birth_txg = db->db_blkptr->blk_birth; 1038 } 1039 1040 /* 1041 * If this block don't exist or is in a snapshot, it can't be freed. 1042 * Don't pass the bp to dsl_dataset_block_freeable() since we 1043 * are holding the db_mtx lock and might deadlock if we are 1044 * prefetching a dedup-ed block. 1045 */ 1046 if (birth_txg != 0) 1047 return (ds == NULL || 1048 dsl_dataset_block_freeable(ds, NULL, birth_txg)); 1049 else 1050 return (B_FALSE); 1051} 1052 1053void 1054dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx) 1055{ 1056 arc_buf_t *buf, *obuf; 1057 int osize = db->db.db_size; 1058 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 1059 dnode_t *dn; 1060 1061 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1062 1063 DB_DNODE_ENTER(db); 1064 dn = DB_DNODE(db); 1065 1066 /* XXX does *this* func really need the lock? */ 1067 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 1068 1069 /* 1070 * This call to dmu_buf_will_dirty() with the dn_struct_rwlock held 1071 * is OK, because there can be no other references to the db 1072 * when we are changing its size, so no concurrent DB_FILL can 1073 * be happening. 1074 */ 1075 /* 1076 * XXX we should be doing a dbuf_read, checking the return 1077 * value and returning that up to our callers 1078 */ 1079 dmu_buf_will_dirty(&db->db, tx); 1080 1081 /* create the data buffer for the new block */ 1082 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type); 1083 1084 /* copy old block data to the new block */ 1085 obuf = db->db_buf; 1086 bcopy(obuf->b_data, buf->b_data, MIN(osize, size)); 1087 /* zero the remainder */ 1088 if (size > osize) 1089 bzero((uint8_t *)buf->b_data + osize, size - osize); 1090 1091 mutex_enter(&db->db_mtx); 1092 dbuf_set_data(db, buf); 1093 VERIFY(arc_buf_remove_ref(obuf, db)); 1094 db->db.db_size = size; 1095 1096 if (db->db_level == 0) { 1097 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 1098 db->db_last_dirty->dt.dl.dr_data = buf; 1099 } 1100 mutex_exit(&db->db_mtx); 1101 1102 dnode_willuse_space(dn, size-osize, tx); 1103 DB_DNODE_EXIT(db); 1104} 1105 1106void 1107dbuf_release_bp(dmu_buf_impl_t *db) 1108{ 1109 objset_t *os = db->db_objset; 1110 1111 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os))); 1112 ASSERT(arc_released(os->os_phys_buf) || 1113 list_link_active(&os->os_dsl_dataset->ds_synced_link)); 1114 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf)); 1115 1116 (void) arc_release(db->db_buf, db); 1117} 1118 1119dbuf_dirty_record_t * 1120dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1121{ 1122 dnode_t *dn; 1123 objset_t *os; 1124 dbuf_dirty_record_t **drp, *dr; 1125 int drop_struct_lock = FALSE; 1126 boolean_t do_free_accounting = B_FALSE; 1127 int txgoff = tx->tx_txg & TXG_MASK; 1128 1129 ASSERT(tx->tx_txg != 0); 1130 ASSERT(!refcount_is_zero(&db->db_holds)); 1131 DMU_TX_DIRTY_BUF(tx, db); 1132 1133 DB_DNODE_ENTER(db); 1134 dn = DB_DNODE(db); 1135 /* 1136 * Shouldn't dirty a regular buffer in syncing context. Private 1137 * objects may be dirtied in syncing context, but only if they 1138 * were already pre-dirtied in open context. 1139 */ 1140 ASSERT(!dmu_tx_is_syncing(tx) || 1141 BP_IS_HOLE(dn->dn_objset->os_rootbp) || 1142 DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1143 dn->dn_objset->os_dsl_dataset == NULL); 1144 /* 1145 * We make this assert for private objects as well, but after we 1146 * check if we're already dirty. They are allowed to re-dirty 1147 * in syncing context. 1148 */ 1149 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1150 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1151 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1152 1153 mutex_enter(&db->db_mtx); 1154 /* 1155 * XXX make this true for indirects too? The problem is that 1156 * transactions created with dmu_tx_create_assigned() from 1157 * syncing context don't bother holding ahead. 1158 */ 1159 ASSERT(db->db_level != 0 || 1160 db->db_state == DB_CACHED || db->db_state == DB_FILL || 1161 db->db_state == DB_NOFILL); 1162 1163 mutex_enter(&dn->dn_mtx); 1164 /* 1165 * Don't set dirtyctx to SYNC if we're just modifying this as we 1166 * initialize the objset. 1167 */ 1168 if (dn->dn_dirtyctx == DN_UNDIRTIED && 1169 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) { 1170 dn->dn_dirtyctx = 1171 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN); 1172 ASSERT(dn->dn_dirtyctx_firstset == NULL); 1173 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP); 1174 } 1175 mutex_exit(&dn->dn_mtx); 1176 1177 if (db->db_blkid == DMU_SPILL_BLKID) 1178 dn->dn_have_spill = B_TRUE; 1179 1180 /* 1181 * If this buffer is already dirty, we're done. 1182 */ 1183 drp = &db->db_last_dirty; 1184 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg || 1185 db->db.db_object == DMU_META_DNODE_OBJECT); 1186 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg) 1187 drp = &dr->dr_next; 1188 if (dr && dr->dr_txg == tx->tx_txg) { 1189 DB_DNODE_EXIT(db); 1190 1191 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) { 1192 /* 1193 * If this buffer has already been written out, 1194 * we now need to reset its state. 1195 */ 1196 dbuf_unoverride(dr); 1197 if (db->db.db_object != DMU_META_DNODE_OBJECT && 1198 db->db_state != DB_NOFILL) 1199 arc_buf_thaw(db->db_buf); 1200 } 1201 mutex_exit(&db->db_mtx); 1202 return (dr); 1203 } 1204 1205 /* 1206 * Only valid if not already dirty. 1207 */ 1208 ASSERT(dn->dn_object == 0 || 1209 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1210 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1211 1212 ASSERT3U(dn->dn_nlevels, >, db->db_level); 1213 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) || 1214 dn->dn_phys->dn_nlevels > db->db_level || 1215 dn->dn_next_nlevels[txgoff] > db->db_level || 1216 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level || 1217 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level); 1218 1219 /* 1220 * We should only be dirtying in syncing context if it's the 1221 * mos or we're initializing the os or it's a special object. 1222 * However, we are allowed to dirty in syncing context provided 1223 * we already dirtied it in open context. Hence we must make 1224 * this assertion only if we're not already dirty. 1225 */ 1226 os = dn->dn_objset; 1227 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1228 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp)); 1229 ASSERT(db->db.db_size != 0); 1230 1231 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1232 1233 if (db->db_blkid != DMU_BONUS_BLKID) { 1234 /* 1235 * Update the accounting. 1236 * Note: we delay "free accounting" until after we drop 1237 * the db_mtx. This keeps us from grabbing other locks 1238 * (and possibly deadlocking) in bp_get_dsize() while 1239 * also holding the db_mtx. 1240 */ 1241 dnode_willuse_space(dn, db->db.db_size, tx); 1242 do_free_accounting = dbuf_block_freeable(db); 1243 } 1244 1245 /* 1246 * If this buffer is dirty in an old transaction group we need 1247 * to make a copy of it so that the changes we make in this 1248 * transaction group won't leak out when we sync the older txg. 1249 */ 1250 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP); 1251 if (db->db_level == 0) { 1252 void *data_old = db->db_buf; 1253 1254 if (db->db_state != DB_NOFILL) { 1255 if (db->db_blkid == DMU_BONUS_BLKID) { 1256 dbuf_fix_old_data(db, tx->tx_txg); 1257 data_old = db->db.db_data; 1258 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) { 1259 /* 1260 * Release the data buffer from the cache so 1261 * that we can modify it without impacting 1262 * possible other users of this cached data 1263 * block. Note that indirect blocks and 1264 * private objects are not released until the 1265 * syncing state (since they are only modified 1266 * then). 1267 */ 1268 arc_release(db->db_buf, db); 1269 dbuf_fix_old_data(db, tx->tx_txg); 1270 data_old = db->db_buf; 1271 } 1272 ASSERT(data_old != NULL); 1273 } 1274 dr->dt.dl.dr_data = data_old; 1275 } else { 1276 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL); 1277 list_create(&dr->dt.di.dr_children, 1278 sizeof (dbuf_dirty_record_t), 1279 offsetof(dbuf_dirty_record_t, dr_dirty_node)); 1280 } 1281 if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL) 1282 dr->dr_accounted = db->db.db_size; 1283 dr->dr_dbuf = db; 1284 dr->dr_txg = tx->tx_txg; 1285 dr->dr_next = *drp; 1286 *drp = dr; 1287 1288 /* 1289 * We could have been freed_in_flight between the dbuf_noread 1290 * and dbuf_dirty. We win, as though the dbuf_noread() had 1291 * happened after the free. 1292 */ 1293 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1294 db->db_blkid != DMU_SPILL_BLKID) { 1295 mutex_enter(&dn->dn_mtx); 1296 if (dn->dn_free_ranges[txgoff] != NULL) { 1297 range_tree_clear(dn->dn_free_ranges[txgoff], 1298 db->db_blkid, 1); 1299 } 1300 mutex_exit(&dn->dn_mtx); 1301 db->db_freed_in_flight = FALSE; 1302 } 1303 1304 /* 1305 * This buffer is now part of this txg 1306 */ 1307 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg); 1308 db->db_dirtycnt += 1; 1309 ASSERT3U(db->db_dirtycnt, <=, 3); 1310 1311 mutex_exit(&db->db_mtx); 1312 1313 if (db->db_blkid == DMU_BONUS_BLKID || 1314 db->db_blkid == DMU_SPILL_BLKID) { 1315 mutex_enter(&dn->dn_mtx); 1316 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1317 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1318 mutex_exit(&dn->dn_mtx); 1319 dnode_setdirty(dn, tx); 1320 DB_DNODE_EXIT(db); 1321 return (dr); 1322 } else if (do_free_accounting) { 1323 blkptr_t *bp = db->db_blkptr; 1324 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ? 1325 bp_get_dsize(os->os_spa, bp) : db->db.db_size; 1326 /* 1327 * This is only a guess -- if the dbuf is dirty 1328 * in a previous txg, we don't know how much 1329 * space it will use on disk yet. We should 1330 * really have the struct_rwlock to access 1331 * db_blkptr, but since this is just a guess, 1332 * it's OK if we get an odd answer. 1333 */ 1334 ddt_prefetch(os->os_spa, bp); 1335 dnode_willuse_space(dn, -willfree, tx); 1336 } 1337 1338 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 1339 rw_enter(&dn->dn_struct_rwlock, RW_READER); 1340 drop_struct_lock = TRUE; 1341 } 1342 1343 if (db->db_level == 0) { 1344 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock); 1345 ASSERT(dn->dn_maxblkid >= db->db_blkid); 1346 } 1347 1348 if (db->db_level+1 < dn->dn_nlevels) { 1349 dmu_buf_impl_t *parent = db->db_parent; 1350 dbuf_dirty_record_t *di; 1351 int parent_held = FALSE; 1352 1353 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) { 1354 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1355 1356 parent = dbuf_hold_level(dn, db->db_level+1, 1357 db->db_blkid >> epbs, FTAG); 1358 ASSERT(parent != NULL); 1359 parent_held = TRUE; 1360 } 1361 if (drop_struct_lock) 1362 rw_exit(&dn->dn_struct_rwlock); 1363 ASSERT3U(db->db_level+1, ==, parent->db_level); 1364 di = dbuf_dirty(parent, tx); 1365 if (parent_held) 1366 dbuf_rele(parent, FTAG); 1367 1368 mutex_enter(&db->db_mtx); 1369 /* 1370 * Since we've dropped the mutex, it's possible that 1371 * dbuf_undirty() might have changed this out from under us. 1372 */ 1373 if (db->db_last_dirty == dr || 1374 dn->dn_object == DMU_META_DNODE_OBJECT) { 1375 mutex_enter(&di->dt.di.dr_mtx); 1376 ASSERT3U(di->dr_txg, ==, tx->tx_txg); 1377 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1378 list_insert_tail(&di->dt.di.dr_children, dr); 1379 mutex_exit(&di->dt.di.dr_mtx); 1380 dr->dr_parent = di; 1381 } 1382 mutex_exit(&db->db_mtx); 1383 } else { 1384 ASSERT(db->db_level+1 == dn->dn_nlevels); 1385 ASSERT(db->db_blkid < dn->dn_nblkptr); 1386 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf); 1387 mutex_enter(&dn->dn_mtx); 1388 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1389 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1390 mutex_exit(&dn->dn_mtx); 1391 if (drop_struct_lock) 1392 rw_exit(&dn->dn_struct_rwlock); 1393 } 1394 1395 dnode_setdirty(dn, tx); 1396 DB_DNODE_EXIT(db); 1397 return (dr); 1398} 1399 1400/* 1401 * Undirty a buffer in the transaction group referenced by the given 1402 * transaction. Return whether this evicted the dbuf. 1403 */ 1404static boolean_t 1405dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1406{ 1407 dnode_t *dn; 1408 uint64_t txg = tx->tx_txg; 1409 dbuf_dirty_record_t *dr, **drp; 1410 1411 ASSERT(txg != 0); 1412 1413 /* 1414 * Due to our use of dn_nlevels below, this can only be called 1415 * in open context, unless we are operating on the MOS. 1416 * From syncing context, dn_nlevels may be different from the 1417 * dn_nlevels used when dbuf was dirtied. 1418 */ 1419 ASSERT(db->db_objset == 1420 dmu_objset_pool(db->db_objset)->dp_meta_objset || 1421 txg != spa_syncing_txg(dmu_objset_spa(db->db_objset))); 1422 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1423 ASSERT0(db->db_level); 1424 ASSERT(MUTEX_HELD(&db->db_mtx)); 1425 1426 /* 1427 * If this buffer is not dirty, we're done. 1428 */ 1429 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next) 1430 if (dr->dr_txg <= txg) 1431 break; 1432 if (dr == NULL || dr->dr_txg < txg) 1433 return (B_FALSE); 1434 ASSERT(dr->dr_txg == txg); 1435 ASSERT(dr->dr_dbuf == db); 1436 1437 DB_DNODE_ENTER(db); 1438 dn = DB_DNODE(db); 1439 1440 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1441 1442 ASSERT(db->db.db_size != 0); 1443 1444 dsl_pool_undirty_space(dmu_objset_pool(dn->dn_objset), 1445 dr->dr_accounted, txg); 1446 1447 *drp = dr->dr_next; 1448 1449 /* 1450 * Note that there are three places in dbuf_dirty() 1451 * where this dirty record may be put on a list. 1452 * Make sure to do a list_remove corresponding to 1453 * every one of those list_insert calls. 1454 */ 1455 if (dr->dr_parent) { 1456 mutex_enter(&dr->dr_parent->dt.di.dr_mtx); 1457 list_remove(&dr->dr_parent->dt.di.dr_children, dr); 1458 mutex_exit(&dr->dr_parent->dt.di.dr_mtx); 1459 } else if (db->db_blkid == DMU_SPILL_BLKID || 1460 db->db_level + 1 == dn->dn_nlevels) { 1461 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf); 1462 mutex_enter(&dn->dn_mtx); 1463 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr); 1464 mutex_exit(&dn->dn_mtx); 1465 } 1466 DB_DNODE_EXIT(db); 1467 1468 if (db->db_state != DB_NOFILL) { 1469 dbuf_unoverride(dr); 1470 1471 ASSERT(db->db_buf != NULL); 1472 ASSERT(dr->dt.dl.dr_data != NULL); 1473 if (dr->dt.dl.dr_data != db->db_buf) 1474 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db)); 1475 } 1476 1477 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 1478 1479 ASSERT(db->db_dirtycnt > 0); 1480 db->db_dirtycnt -= 1; 1481 1482 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) { 1483 arc_buf_t *buf = db->db_buf; 1484 1485 ASSERT(db->db_state == DB_NOFILL || arc_released(buf)); 1486 dbuf_clear_data(db); 1487 VERIFY(arc_buf_remove_ref(buf, db)); 1488 dbuf_evict(db); 1489 return (B_TRUE); 1490 } 1491 1492 return (B_FALSE); 1493} 1494 1495void 1496dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx) 1497{ 1498 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1499 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH; 1500 1501 ASSERT(tx->tx_txg != 0); 1502 ASSERT(!refcount_is_zero(&db->db_holds)); 1503 1504 DB_DNODE_ENTER(db); 1505 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock)) 1506 rf |= DB_RF_HAVESTRUCT; 1507 DB_DNODE_EXIT(db); 1508 (void) dbuf_read(db, NULL, rf); 1509 (void) dbuf_dirty(db, tx); 1510} 1511 1512void 1513dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1514{ 1515 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1516 1517 db->db_state = DB_NOFILL; 1518 1519 dmu_buf_will_fill(db_fake, tx); 1520} 1521 1522void 1523dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1524{ 1525 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1526 1527 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1528 ASSERT(tx->tx_txg != 0); 1529 ASSERT(db->db_level == 0); 1530 ASSERT(!refcount_is_zero(&db->db_holds)); 1531 1532 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT || 1533 dmu_tx_private_ok(tx)); 1534 1535 dbuf_noread(db); 1536 (void) dbuf_dirty(db, tx); 1537} 1538 1539#pragma weak dmu_buf_fill_done = dbuf_fill_done 1540/* ARGSUSED */ 1541void 1542dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx) 1543{ 1544 mutex_enter(&db->db_mtx); 1545 DBUF_VERIFY(db); 1546 1547 if (db->db_state == DB_FILL) { 1548 if (db->db_level == 0 && db->db_freed_in_flight) { 1549 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1550 /* we were freed while filling */ 1551 /* XXX dbuf_undirty? */ 1552 bzero(db->db.db_data, db->db.db_size); 1553 db->db_freed_in_flight = FALSE; 1554 } 1555 db->db_state = DB_CACHED; 1556 cv_broadcast(&db->db_changed); 1557 } 1558 mutex_exit(&db->db_mtx); 1559} 1560 1561void 1562dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data, 1563 bp_embedded_type_t etype, enum zio_compress comp, 1564 int uncompressed_size, int compressed_size, int byteorder, 1565 dmu_tx_t *tx) 1566{ 1567 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 1568 struct dirty_leaf *dl; 1569 dmu_object_type_t type; 1570 1571 if (etype == BP_EMBEDDED_TYPE_DATA) { 1572 ASSERT(spa_feature_is_active(dmu_objset_spa(db->db_objset), 1573 SPA_FEATURE_EMBEDDED_DATA)); 1574 } 1575 1576 DB_DNODE_ENTER(db); 1577 type = DB_DNODE(db)->dn_type; 1578 DB_DNODE_EXIT(db); 1579 1580 ASSERT0(db->db_level); 1581 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1582 1583 dmu_buf_will_not_fill(dbuf, tx); 1584 1585 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 1586 dl = &db->db_last_dirty->dt.dl; 1587 encode_embedded_bp_compressed(&dl->dr_overridden_by, 1588 data, comp, uncompressed_size, compressed_size); 1589 BPE_SET_ETYPE(&dl->dr_overridden_by, etype); 1590 BP_SET_TYPE(&dl->dr_overridden_by, type); 1591 BP_SET_LEVEL(&dl->dr_overridden_by, 0); 1592 BP_SET_BYTEORDER(&dl->dr_overridden_by, byteorder); 1593 1594 dl->dr_override_state = DR_OVERRIDDEN; 1595 dl->dr_overridden_by.blk_birth = db->db_last_dirty->dr_txg; 1596} 1597 1598/* 1599 * Directly assign a provided arc buf to a given dbuf if it's not referenced 1600 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf. 1601 */ 1602void 1603dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx) 1604{ 1605 ASSERT(!refcount_is_zero(&db->db_holds)); 1606 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1607 ASSERT(db->db_level == 0); 1608 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA); 1609 ASSERT(buf != NULL); 1610 ASSERT(arc_buf_size(buf) == db->db.db_size); 1611 ASSERT(tx->tx_txg != 0); 1612 1613 arc_return_buf(buf, db); 1614 ASSERT(arc_released(buf)); 1615 1616 mutex_enter(&db->db_mtx); 1617 1618 while (db->db_state == DB_READ || db->db_state == DB_FILL) 1619 cv_wait(&db->db_changed, &db->db_mtx); 1620 1621 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED); 1622 1623 if (db->db_state == DB_CACHED && 1624 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) { 1625 mutex_exit(&db->db_mtx); 1626 (void) dbuf_dirty(db, tx); 1627 bcopy(buf->b_data, db->db.db_data, db->db.db_size); 1628 VERIFY(arc_buf_remove_ref(buf, db)); 1629 xuio_stat_wbuf_copied(); 1630 return; 1631 } 1632 1633 xuio_stat_wbuf_nocopy(); 1634 if (db->db_state == DB_CACHED) { 1635 dbuf_dirty_record_t *dr = db->db_last_dirty; 1636 1637 ASSERT(db->db_buf != NULL); 1638 if (dr != NULL && dr->dr_txg == tx->tx_txg) { 1639 ASSERT(dr->dt.dl.dr_data == db->db_buf); 1640 if (!arc_released(db->db_buf)) { 1641 ASSERT(dr->dt.dl.dr_override_state == 1642 DR_OVERRIDDEN); 1643 arc_release(db->db_buf, db); 1644 } 1645 dr->dt.dl.dr_data = buf; 1646 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1647 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) { 1648 arc_release(db->db_buf, db); 1649 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1650 } 1651 db->db_buf = NULL; 1652 } 1653 ASSERT(db->db_buf == NULL); 1654 dbuf_set_data(db, buf); 1655 db->db_state = DB_FILL; 1656 mutex_exit(&db->db_mtx); 1657 (void) dbuf_dirty(db, tx); 1658 dmu_buf_fill_done(&db->db, tx); 1659} 1660 1661/* 1662 * "Clear" the contents of this dbuf. This will mark the dbuf 1663 * EVICTING and clear *most* of its references. Unfortunately, 1664 * when we are not holding the dn_dbufs_mtx, we can't clear the 1665 * entry in the dn_dbufs list. We have to wait until dbuf_destroy() 1666 * in this case. For callers from the DMU we will usually see: 1667 * dbuf_clear()->arc_clear_callback()->dbuf_do_evict()->dbuf_destroy() 1668 * For the arc callback, we will usually see: 1669 * dbuf_do_evict()->dbuf_clear();dbuf_destroy() 1670 * Sometimes, though, we will get a mix of these two: 1671 * DMU: dbuf_clear()->arc_clear_callback() 1672 * ARC: dbuf_do_evict()->dbuf_destroy() 1673 * 1674 * This routine will dissociate the dbuf from the arc, by calling 1675 * arc_clear_callback(), but will not evict the data from the ARC. 1676 */ 1677void 1678dbuf_clear(dmu_buf_impl_t *db) 1679{ 1680 dnode_t *dn; 1681 dmu_buf_impl_t *parent = db->db_parent; 1682 dmu_buf_impl_t *dndb; 1683 boolean_t dbuf_gone = B_FALSE; 1684 1685 ASSERT(MUTEX_HELD(&db->db_mtx)); 1686 ASSERT(refcount_is_zero(&db->db_holds)); 1687 1688 dbuf_evict_user(db); 1689 1690 if (db->db_state == DB_CACHED) { 1691 ASSERT(db->db.db_data != NULL); 1692 if (db->db_blkid == DMU_BONUS_BLKID) { 1693 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN); 1694 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 1695 } 1696 db->db.db_data = NULL; 1697 db->db_state = DB_UNCACHED; 1698 } 1699 1700 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL); 1701 ASSERT(db->db_data_pending == NULL); 1702 1703 db->db_state = DB_EVICTING; 1704 db->db_blkptr = NULL; 1705 1706 DB_DNODE_ENTER(db); 1707 dn = DB_DNODE(db); 1708 dndb = dn->dn_dbuf; 1709 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) { 1710 avl_remove(&dn->dn_dbufs, db); 1711 atomic_dec_32(&dn->dn_dbufs_count); 1712 membar_producer(); 1713 DB_DNODE_EXIT(db); 1714 /* 1715 * Decrementing the dbuf count means that the hold corresponding 1716 * to the removed dbuf is no longer discounted in dnode_move(), 1717 * so the dnode cannot be moved until after we release the hold. 1718 * The membar_producer() ensures visibility of the decremented 1719 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually 1720 * release any lock. 1721 */ 1722 dnode_rele(dn, db); 1723 db->db_dnode_handle = NULL; 1724 } else { 1725 DB_DNODE_EXIT(db); 1726 } 1727 1728 if (db->db_buf) 1729 dbuf_gone = arc_clear_callback(db->db_buf); 1730 1731 if (!dbuf_gone) 1732 mutex_exit(&db->db_mtx); 1733 1734 /* 1735 * If this dbuf is referenced from an indirect dbuf, 1736 * decrement the ref count on the indirect dbuf. 1737 */ 1738 if (parent && parent != dndb) 1739 dbuf_rele(parent, db); 1740} 1741 1742/* 1743 * Note: While bpp will always be updated if the function returns success, 1744 * parentp will not be updated if the dnode does not have dn_dbuf filled in; 1745 * this happens when the dnode is the meta-dnode, or a userused or groupused 1746 * object. 1747 */ 1748static int 1749dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, 1750 dmu_buf_impl_t **parentp, blkptr_t **bpp) 1751{ 1752 int nlevels, epbs; 1753 1754 *parentp = NULL; 1755 *bpp = NULL; 1756 1757 ASSERT(blkid != DMU_BONUS_BLKID); 1758 1759 if (blkid == DMU_SPILL_BLKID) { 1760 mutex_enter(&dn->dn_mtx); 1761 if (dn->dn_have_spill && 1762 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) 1763 *bpp = &dn->dn_phys->dn_spill; 1764 else 1765 *bpp = NULL; 1766 dbuf_add_ref(dn->dn_dbuf, NULL); 1767 *parentp = dn->dn_dbuf; 1768 mutex_exit(&dn->dn_mtx); 1769 return (0); 1770 } 1771 1772 if (dn->dn_phys->dn_nlevels == 0) 1773 nlevels = 1; 1774 else 1775 nlevels = dn->dn_phys->dn_nlevels; 1776 1777 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1778 1779 ASSERT3U(level * epbs, <, 64); 1780 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1781 if (level >= nlevels || 1782 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) { 1783 /* the buffer has no parent yet */ 1784 return (SET_ERROR(ENOENT)); 1785 } else if (level < nlevels-1) { 1786 /* this block is referenced from an indirect block */ 1787 int err = dbuf_hold_impl(dn, level+1, 1788 blkid >> epbs, fail_sparse, FALSE, NULL, parentp); 1789 if (err) 1790 return (err); 1791 err = dbuf_read(*parentp, NULL, 1792 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL)); 1793 if (err) { 1794 dbuf_rele(*parentp, NULL); 1795 *parentp = NULL; 1796 return (err); 1797 } 1798 *bpp = ((blkptr_t *)(*parentp)->db.db_data) + 1799 (blkid & ((1ULL << epbs) - 1)); 1800 return (0); 1801 } else { 1802 /* the block is referenced from the dnode */ 1803 ASSERT3U(level, ==, nlevels-1); 1804 ASSERT(dn->dn_phys->dn_nblkptr == 0 || 1805 blkid < dn->dn_phys->dn_nblkptr); 1806 if (dn->dn_dbuf) { 1807 dbuf_add_ref(dn->dn_dbuf, NULL); 1808 *parentp = dn->dn_dbuf; 1809 } 1810 *bpp = &dn->dn_phys->dn_blkptr[blkid]; 1811 return (0); 1812 } 1813} 1814 1815static dmu_buf_impl_t * 1816dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid, 1817 dmu_buf_impl_t *parent, blkptr_t *blkptr) 1818{ 1819 objset_t *os = dn->dn_objset; 1820 dmu_buf_impl_t *db, *odb; 1821 1822 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1823 ASSERT(dn->dn_type != DMU_OT_NONE); 1824 1825 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP); 1826 1827 db->db_objset = os; 1828 db->db.db_object = dn->dn_object; 1829 db->db_level = level; 1830 db->db_blkid = blkid; 1831 db->db_last_dirty = NULL; 1832 db->db_dirtycnt = 0; 1833 db->db_dnode_handle = dn->dn_handle; 1834 db->db_parent = parent; 1835 db->db_blkptr = blkptr; 1836 1837 db->db_user = NULL; 1838 db->db_immediate_evict = 0; 1839 db->db_freed_in_flight = 0; 1840 1841 if (blkid == DMU_BONUS_BLKID) { 1842 ASSERT3P(parent, ==, dn->dn_dbuf); 1843 db->db.db_size = DN_MAX_BONUSLEN - 1844 (dn->dn_nblkptr-1) * sizeof (blkptr_t); 1845 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 1846 db->db.db_offset = DMU_BONUS_BLKID; 1847 db->db_state = DB_UNCACHED; 1848 /* the bonus dbuf is not placed in the hash table */ 1849 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1850 return (db); 1851 } else if (blkid == DMU_SPILL_BLKID) { 1852 db->db.db_size = (blkptr != NULL) ? 1853 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE; 1854 db->db.db_offset = 0; 1855 } else { 1856 int blocksize = 1857 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz; 1858 db->db.db_size = blocksize; 1859 db->db.db_offset = db->db_blkid * blocksize; 1860 } 1861 1862 /* 1863 * Hold the dn_dbufs_mtx while we get the new dbuf 1864 * in the hash table *and* added to the dbufs list. 1865 * This prevents a possible deadlock with someone 1866 * trying to look up this dbuf before its added to the 1867 * dn_dbufs list. 1868 */ 1869 mutex_enter(&dn->dn_dbufs_mtx); 1870 db->db_state = DB_EVICTING; 1871 if ((odb = dbuf_hash_insert(db)) != NULL) { 1872 /* someone else inserted it first */ 1873 kmem_cache_free(dbuf_cache, db); 1874 mutex_exit(&dn->dn_dbufs_mtx); 1875 return (odb); 1876 } 1877 avl_add(&dn->dn_dbufs, db); 1878 if (db->db_level == 0 && db->db_blkid >= 1879 dn->dn_unlisted_l0_blkid) 1880 dn->dn_unlisted_l0_blkid = db->db_blkid + 1; 1881 db->db_state = DB_UNCACHED; 1882 mutex_exit(&dn->dn_dbufs_mtx); 1883 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1884 1885 if (parent && parent != dn->dn_dbuf) 1886 dbuf_add_ref(parent, db); 1887 1888 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1889 refcount_count(&dn->dn_holds) > 0); 1890 (void) refcount_add(&dn->dn_holds, db); 1891 atomic_inc_32(&dn->dn_dbufs_count); 1892 1893 dprintf_dbuf(db, "db=%p\n", db); 1894 1895 return (db); 1896} 1897 1898static int 1899dbuf_do_evict(void *private) 1900{ 1901 dmu_buf_impl_t *db = private; 1902 1903 if (!MUTEX_HELD(&db->db_mtx)) 1904 mutex_enter(&db->db_mtx); 1905 1906 ASSERT(refcount_is_zero(&db->db_holds)); 1907 1908 if (db->db_state != DB_EVICTING) { 1909 ASSERT(db->db_state == DB_CACHED); 1910 DBUF_VERIFY(db); 1911 db->db_buf = NULL; 1912 dbuf_evict(db); 1913 } else { 1914 mutex_exit(&db->db_mtx); 1915 dbuf_destroy(db); 1916 } 1917 return (0); 1918} 1919 1920static void 1921dbuf_destroy(dmu_buf_impl_t *db) 1922{ 1923 ASSERT(refcount_is_zero(&db->db_holds)); 1924 1925 if (db->db_blkid != DMU_BONUS_BLKID) { 1926 /* 1927 * If this dbuf is still on the dn_dbufs list, 1928 * remove it from that list. 1929 */ 1930 if (db->db_dnode_handle != NULL) { 1931 dnode_t *dn; 1932 1933 DB_DNODE_ENTER(db); 1934 dn = DB_DNODE(db); 1935 mutex_enter(&dn->dn_dbufs_mtx); 1936 avl_remove(&dn->dn_dbufs, db); 1937 atomic_dec_32(&dn->dn_dbufs_count); 1938 mutex_exit(&dn->dn_dbufs_mtx); 1939 DB_DNODE_EXIT(db); 1940 /* 1941 * Decrementing the dbuf count means that the hold 1942 * corresponding to the removed dbuf is no longer 1943 * discounted in dnode_move(), so the dnode cannot be 1944 * moved until after we release the hold. 1945 */ 1946 dnode_rele(dn, db); 1947 db->db_dnode_handle = NULL; 1948 } 1949 dbuf_hash_remove(db); 1950 } 1951 db->db_parent = NULL; 1952 db->db_buf = NULL; 1953 1954 ASSERT(db->db.db_data == NULL); 1955 ASSERT(db->db_hash_next == NULL); 1956 ASSERT(db->db_blkptr == NULL); 1957 ASSERT(db->db_data_pending == NULL); 1958 1959 kmem_cache_free(dbuf_cache, db); 1960 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1961} 1962 1963typedef struct dbuf_prefetch_arg { 1964 spa_t *dpa_spa; /* The spa to issue the prefetch in. */ 1965 zbookmark_phys_t dpa_zb; /* The target block to prefetch. */ 1966 int dpa_epbs; /* Entries (blkptr_t's) Per Block Shift. */ 1967 int dpa_curlevel; /* The current level that we're reading */ 1968 zio_priority_t dpa_prio; /* The priority I/Os should be issued at. */ 1969 zio_t *dpa_zio; /* The parent zio_t for all prefetches. */ 1970 arc_flags_t dpa_aflags; /* Flags to pass to the final prefetch. */ 1971} dbuf_prefetch_arg_t; 1972 1973/* 1974 * Actually issue the prefetch read for the block given. 1975 */ 1976static void 1977dbuf_issue_final_prefetch(dbuf_prefetch_arg_t *dpa, blkptr_t *bp) 1978{ 1979 if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) 1980 return; 1981 1982 arc_flags_t aflags = 1983 dpa->dpa_aflags | ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH; 1984 1985 ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); 1986 ASSERT3U(dpa->dpa_curlevel, ==, dpa->dpa_zb.zb_level); 1987 ASSERT(dpa->dpa_zio != NULL); 1988 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, bp, NULL, NULL, 1989 dpa->dpa_prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 1990 &aflags, &dpa->dpa_zb); 1991} 1992 1993/* 1994 * Called when an indirect block above our prefetch target is read in. This 1995 * will either read in the next indirect block down the tree or issue the actual 1996 * prefetch if the next block down is our target. 1997 */ 1998static void 1999dbuf_prefetch_indirect_done(zio_t *zio, arc_buf_t *abuf, void *private) 2000{ 2001 dbuf_prefetch_arg_t *dpa = private; 2002 2003 ASSERT3S(dpa->dpa_zb.zb_level, <, dpa->dpa_curlevel); 2004 ASSERT3S(dpa->dpa_curlevel, >, 0); 2005 if (zio != NULL) { 2006 ASSERT3S(BP_GET_LEVEL(zio->io_bp), ==, dpa->dpa_curlevel); 2007 ASSERT3U(BP_GET_LSIZE(zio->io_bp), ==, zio->io_size); 2008 ASSERT3P(zio->io_spa, ==, dpa->dpa_spa); 2009 } 2010 2011 dpa->dpa_curlevel--; 2012 2013 uint64_t nextblkid = dpa->dpa_zb.zb_blkid >> 2014 (dpa->dpa_epbs * (dpa->dpa_curlevel - dpa->dpa_zb.zb_level)); 2015 blkptr_t *bp = ((blkptr_t *)abuf->b_data) + 2016 P2PHASE(nextblkid, 1ULL << dpa->dpa_epbs); 2017 if (BP_IS_HOLE(bp) || (zio != NULL && zio->io_error != 0)) { 2018 kmem_free(dpa, sizeof (*dpa)); 2019 } else if (dpa->dpa_curlevel == dpa->dpa_zb.zb_level) { 2020 ASSERT3U(nextblkid, ==, dpa->dpa_zb.zb_blkid); 2021 dbuf_issue_final_prefetch(dpa, bp); 2022 kmem_free(dpa, sizeof (*dpa)); 2023 } else { 2024 arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; 2025 zbookmark_phys_t zb; 2026 2027 ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); 2028 2029 SET_BOOKMARK(&zb, dpa->dpa_zb.zb_objset, 2030 dpa->dpa_zb.zb_object, dpa->dpa_curlevel, nextblkid); 2031 2032 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, 2033 bp, dbuf_prefetch_indirect_done, dpa, dpa->dpa_prio, 2034 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2035 &iter_aflags, &zb); 2036 } 2037 (void) arc_buf_remove_ref(abuf, private); 2038} 2039 2040/* 2041 * Issue prefetch reads for the given block on the given level. If the indirect 2042 * blocks above that block are not in memory, we will read them in 2043 * asynchronously. As a result, this call never blocks waiting for a read to 2044 * complete. 2045 */ 2046void 2047dbuf_prefetch(dnode_t *dn, int64_t level, uint64_t blkid, zio_priority_t prio, 2048 arc_flags_t aflags) 2049{ 2050 blkptr_t bp; 2051 int epbs, nlevels, curlevel; 2052 uint64_t curblkid; 2053 2054 ASSERT(blkid != DMU_BONUS_BLKID); 2055 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 2056 2057 if (dnode_block_freed(dn, blkid)) 2058 return; 2059 2060 /* 2061 * This dnode hasn't been written to disk yet, so there's nothing to 2062 * prefetch. 2063 */ 2064 nlevels = dn->dn_phys->dn_nlevels; 2065 if (level >= nlevels || dn->dn_phys->dn_nblkptr == 0) 2066 return; 2067 2068 epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2069 if (dn->dn_phys->dn_maxblkid < blkid << (epbs * level)) 2070 return; 2071 2072 dmu_buf_impl_t *db = dbuf_find(dn->dn_objset, dn->dn_object, 2073 level, blkid); 2074 if (db != NULL) { 2075 mutex_exit(&db->db_mtx); 2076 /* 2077 * This dbuf already exists. It is either CACHED, or 2078 * (we assume) about to be read or filled. 2079 */ 2080 return; 2081 } 2082 2083 /* 2084 * Find the closest ancestor (indirect block) of the target block 2085 * that is present in the cache. In this indirect block, we will 2086 * find the bp that is at curlevel, curblkid. 2087 */ 2088 curlevel = level; 2089 curblkid = blkid; 2090 while (curlevel < nlevels - 1) { 2091 int parent_level = curlevel + 1; 2092 uint64_t parent_blkid = curblkid >> epbs; 2093 dmu_buf_impl_t *db; 2094 2095 if (dbuf_hold_impl(dn, parent_level, parent_blkid, 2096 FALSE, TRUE, FTAG, &db) == 0) { 2097 blkptr_t *bpp = db->db_buf->b_data; 2098 bp = bpp[P2PHASE(curblkid, 1 << epbs)]; 2099 dbuf_rele(db, FTAG); 2100 break; 2101 } 2102 2103 curlevel = parent_level; 2104 curblkid = parent_blkid; 2105 } 2106 2107 if (curlevel == nlevels - 1) { 2108 /* No cached indirect blocks found. */ 2109 ASSERT3U(curblkid, <, dn->dn_phys->dn_nblkptr); 2110 bp = dn->dn_phys->dn_blkptr[curblkid]; 2111 } 2112 if (BP_IS_HOLE(&bp)) 2113 return; 2114 2115 ASSERT3U(curlevel, ==, BP_GET_LEVEL(&bp)); 2116 2117 zio_t *pio = zio_root(dmu_objset_spa(dn->dn_objset), NULL, NULL, 2118 ZIO_FLAG_CANFAIL); 2119 2120 dbuf_prefetch_arg_t *dpa = kmem_zalloc(sizeof (*dpa), KM_SLEEP); 2121 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; 2122 SET_BOOKMARK(&dpa->dpa_zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, 2123 dn->dn_object, level, blkid); 2124 dpa->dpa_curlevel = curlevel; 2125 dpa->dpa_prio = prio; 2126 dpa->dpa_aflags = aflags; 2127 dpa->dpa_spa = dn->dn_objset->os_spa; 2128 dpa->dpa_epbs = epbs; 2129 dpa->dpa_zio = pio; 2130 2131 /* 2132 * If we have the indirect just above us, no need to do the asynchronous 2133 * prefetch chain; we'll just run the last step ourselves. If we're at 2134 * a higher level, though, we want to issue the prefetches for all the 2135 * indirect blocks asynchronously, so we can go on with whatever we were 2136 * doing. 2137 */ 2138 if (curlevel == level) { 2139 ASSERT3U(curblkid, ==, blkid); 2140 dbuf_issue_final_prefetch(dpa, &bp); 2141 kmem_free(dpa, sizeof (*dpa)); 2142 } else { 2143 arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; 2144 zbookmark_phys_t zb; 2145 2146 SET_BOOKMARK(&zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, 2147 dn->dn_object, curlevel, curblkid); 2148 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, 2149 &bp, dbuf_prefetch_indirect_done, dpa, prio, 2150 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2151 &iter_aflags, &zb); 2152 } 2153 /* 2154 * We use pio here instead of dpa_zio since it's possible that 2155 * dpa may have already been freed. 2156 */ 2157 zio_nowait(pio); 2158} 2159 2160/* 2161 * Returns with db_holds incremented, and db_mtx not held. 2162 * Note: dn_struct_rwlock must be held. 2163 */ 2164int 2165dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, 2166 boolean_t fail_sparse, boolean_t fail_uncached, 2167 void *tag, dmu_buf_impl_t **dbp) 2168{ 2169 dmu_buf_impl_t *db, *parent = NULL; 2170 2171 ASSERT(blkid != DMU_BONUS_BLKID); 2172 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 2173 ASSERT3U(dn->dn_nlevels, >, level); 2174 2175 *dbp = NULL; 2176top: 2177 /* dbuf_find() returns with db_mtx held */ 2178 db = dbuf_find(dn->dn_objset, dn->dn_object, level, blkid); 2179 2180 if (db == NULL) { 2181 blkptr_t *bp = NULL; 2182 int err; 2183 2184 if (fail_uncached) 2185 return (SET_ERROR(ENOENT)); 2186 2187 ASSERT3P(parent, ==, NULL); 2188 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp); 2189 if (fail_sparse) { 2190 if (err == 0 && bp && BP_IS_HOLE(bp)) 2191 err = SET_ERROR(ENOENT); 2192 if (err) { 2193 if (parent) 2194 dbuf_rele(parent, NULL); 2195 return (err); 2196 } 2197 } 2198 if (err && err != ENOENT) 2199 return (err); 2200 db = dbuf_create(dn, level, blkid, parent, bp); 2201 } 2202 2203 if (fail_uncached && db->db_state != DB_CACHED) { 2204 mutex_exit(&db->db_mtx); 2205 return (SET_ERROR(ENOENT)); 2206 } 2207 2208 if (db->db_buf && refcount_is_zero(&db->db_holds)) { 2209 arc_buf_add_ref(db->db_buf, db); 2210 if (db->db_buf->b_data == NULL) { 2211 dbuf_clear(db); 2212 if (parent) { 2213 dbuf_rele(parent, NULL); 2214 parent = NULL; 2215 } 2216 goto top; 2217 } 2218 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data); 2219 } 2220 2221 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf)); 2222 2223 /* 2224 * If this buffer is currently syncing out, and we are are 2225 * still referencing it from db_data, we need to make a copy 2226 * of it in case we decide we want to dirty it again in this txg. 2227 */ 2228 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 2229 dn->dn_object != DMU_META_DNODE_OBJECT && 2230 db->db_state == DB_CACHED && db->db_data_pending) { 2231 dbuf_dirty_record_t *dr = db->db_data_pending; 2232 2233 if (dr->dt.dl.dr_data == db->db_buf) { 2234 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2235 2236 dbuf_set_data(db, 2237 arc_buf_alloc(dn->dn_objset->os_spa, 2238 db->db.db_size, db, type)); 2239 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data, 2240 db->db.db_size); 2241 } 2242 } 2243 2244 (void) refcount_add(&db->db_holds, tag); 2245 DBUF_VERIFY(db); 2246 mutex_exit(&db->db_mtx); 2247 2248 /* NOTE: we can't rele the parent until after we drop the db_mtx */ 2249 if (parent) 2250 dbuf_rele(parent, NULL); 2251 2252 ASSERT3P(DB_DNODE(db), ==, dn); 2253 ASSERT3U(db->db_blkid, ==, blkid); 2254 ASSERT3U(db->db_level, ==, level); 2255 *dbp = db; 2256 2257 return (0); 2258} 2259 2260dmu_buf_impl_t * 2261dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag) 2262{ 2263 return (dbuf_hold_level(dn, 0, blkid, tag)); 2264} 2265 2266dmu_buf_impl_t * 2267dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag) 2268{ 2269 dmu_buf_impl_t *db; 2270 int err = dbuf_hold_impl(dn, level, blkid, FALSE, FALSE, tag, &db); 2271 return (err ? NULL : db); 2272} 2273 2274void 2275dbuf_create_bonus(dnode_t *dn) 2276{ 2277 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 2278 2279 ASSERT(dn->dn_bonus == NULL); 2280 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL); 2281} 2282 2283int 2284dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx) 2285{ 2286 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2287 dnode_t *dn; 2288 2289 if (db->db_blkid != DMU_SPILL_BLKID) 2290 return (SET_ERROR(ENOTSUP)); 2291 if (blksz == 0) 2292 blksz = SPA_MINBLOCKSIZE; 2293 ASSERT3U(blksz, <=, spa_maxblocksize(dmu_objset_spa(db->db_objset))); 2294 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE); 2295 2296 DB_DNODE_ENTER(db); 2297 dn = DB_DNODE(db); 2298 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 2299 dbuf_new_size(db, blksz, tx); 2300 rw_exit(&dn->dn_struct_rwlock); 2301 DB_DNODE_EXIT(db); 2302 2303 return (0); 2304} 2305 2306void 2307dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx) 2308{ 2309 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx); 2310} 2311 2312#pragma weak dmu_buf_add_ref = dbuf_add_ref 2313void 2314dbuf_add_ref(dmu_buf_impl_t *db, void *tag) 2315{ 2316 int64_t holds = refcount_add(&db->db_holds, tag); 2317 ASSERT(holds > 1); 2318} 2319 2320#pragma weak dmu_buf_try_add_ref = dbuf_try_add_ref 2321boolean_t 2322dbuf_try_add_ref(dmu_buf_t *db_fake, objset_t *os, uint64_t obj, uint64_t blkid, 2323 void *tag) 2324{ 2325 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2326 dmu_buf_impl_t *found_db; 2327 boolean_t result = B_FALSE; 2328 2329 if (db->db_blkid == DMU_BONUS_BLKID) 2330 found_db = dbuf_find_bonus(os, obj); 2331 else 2332 found_db = dbuf_find(os, obj, 0, blkid); 2333 2334 if (found_db != NULL) { 2335 if (db == found_db && dbuf_refcount(db) > db->db_dirtycnt) { 2336 (void) refcount_add(&db->db_holds, tag); 2337 result = B_TRUE; 2338 } 2339 mutex_exit(&db->db_mtx); 2340 } 2341 return (result); 2342} 2343 2344/* 2345 * If you call dbuf_rele() you had better not be referencing the dnode handle 2346 * unless you have some other direct or indirect hold on the dnode. (An indirect 2347 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.) 2348 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the 2349 * dnode's parent dbuf evicting its dnode handles. 2350 */ 2351void 2352dbuf_rele(dmu_buf_impl_t *db, void *tag) 2353{ 2354 mutex_enter(&db->db_mtx); 2355 dbuf_rele_and_unlock(db, tag); 2356} 2357 2358void 2359dmu_buf_rele(dmu_buf_t *db, void *tag) 2360{ 2361 dbuf_rele((dmu_buf_impl_t *)db, tag); 2362} 2363 2364/* 2365 * dbuf_rele() for an already-locked dbuf. This is necessary to allow 2366 * db_dirtycnt and db_holds to be updated atomically. 2367 */ 2368void 2369dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) 2370{ 2371 int64_t holds; 2372 2373 ASSERT(MUTEX_HELD(&db->db_mtx)); 2374 DBUF_VERIFY(db); 2375 2376 /* 2377 * Remove the reference to the dbuf before removing its hold on the 2378 * dnode so we can guarantee in dnode_move() that a referenced bonus 2379 * buffer has a corresponding dnode hold. 2380 */ 2381 holds = refcount_remove(&db->db_holds, tag); 2382 ASSERT(holds >= 0); 2383 2384 /* 2385 * We can't freeze indirects if there is a possibility that they 2386 * may be modified in the current syncing context. 2387 */ 2388 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0)) 2389 arc_buf_freeze(db->db_buf); 2390 2391 if (holds == db->db_dirtycnt && 2392 db->db_level == 0 && db->db_immediate_evict) 2393 dbuf_evict_user(db); 2394 2395 if (holds == 0) { 2396 if (db->db_blkid == DMU_BONUS_BLKID) { 2397 dnode_t *dn; 2398 2399 /* 2400 * If the dnode moves here, we cannot cross this 2401 * barrier until the move completes. 2402 */ 2403 DB_DNODE_ENTER(db); 2404 2405 dn = DB_DNODE(db); 2406 atomic_dec_32(&dn->dn_dbufs_count); 2407 2408 /* 2409 * Decrementing the dbuf count means that the bonus 2410 * buffer's dnode hold is no longer discounted in 2411 * dnode_move(). The dnode cannot move until after 2412 * the dnode_rele_and_unlock() below. 2413 */ 2414 DB_DNODE_EXIT(db); 2415 2416 /* 2417 * Do not reference db after its lock is dropped. 2418 * Another thread may evict it. 2419 */ 2420 mutex_exit(&db->db_mtx); 2421 2422 /* 2423 * If the dnode has been freed, evict the bonus 2424 * buffer immediately. The data in the bonus 2425 * buffer is no longer relevant and this prevents 2426 * a stale bonus buffer from being associated 2427 * with this dnode_t should the dnode_t be reused 2428 * prior to being destroyed. 2429 */ 2430 mutex_enter(&dn->dn_mtx); 2431 if (dn->dn_type == DMU_OT_NONE || 2432 dn->dn_free_txg != 0) { 2433 /* 2434 * Drop dn_mtx. It is a leaf lock and 2435 * cannot be held when dnode_evict_bonus() 2436 * acquires other locks in order to 2437 * perform the eviction. 2438 * 2439 * Freed dnodes cannot be reused until the 2440 * last hold is released. Since this bonus 2441 * buffer has a hold, the dnode will remain 2442 * in the free state, even without dn_mtx 2443 * held, until the dnode_rele_and_unlock() 2444 * below. 2445 */ 2446 mutex_exit(&dn->dn_mtx); 2447 dnode_evict_bonus(dn); 2448 mutex_enter(&dn->dn_mtx); 2449 } 2450 dnode_rele_and_unlock(dn, db); 2451 } else if (db->db_buf == NULL) { 2452 /* 2453 * This is a special case: we never associated this 2454 * dbuf with any data allocated from the ARC. 2455 */ 2456 ASSERT(db->db_state == DB_UNCACHED || 2457 db->db_state == DB_NOFILL); 2458 dbuf_evict(db); 2459 } else if (arc_released(db->db_buf)) { 2460 arc_buf_t *buf = db->db_buf; 2461 /* 2462 * This dbuf has anonymous data associated with it. 2463 */ 2464 dbuf_clear_data(db); 2465 VERIFY(arc_buf_remove_ref(buf, db)); 2466 dbuf_evict(db); 2467 } else { 2468 VERIFY(!arc_buf_remove_ref(db->db_buf, db)); 2469 2470 /* 2471 * A dbuf will be eligible for eviction if either the 2472 * 'primarycache' property is set or a duplicate 2473 * copy of this buffer is already cached in the arc. 2474 * 2475 * In the case of the 'primarycache' a buffer 2476 * is considered for eviction if it matches the 2477 * criteria set in the property. 2478 * 2479 * To decide if our buffer is considered a 2480 * duplicate, we must call into the arc to determine 2481 * if multiple buffers are referencing the same 2482 * block on-disk. If so, then we simply evict 2483 * ourselves. 2484 */ 2485 if (!DBUF_IS_CACHEABLE(db)) { 2486 if (db->db_blkptr != NULL && 2487 !BP_IS_HOLE(db->db_blkptr) && 2488 !BP_IS_EMBEDDED(db->db_blkptr)) { 2489 spa_t *spa = 2490 dmu_objset_spa(db->db_objset); 2491 blkptr_t bp = *db->db_blkptr; 2492 dbuf_clear(db); 2493 arc_freed(spa, &bp); 2494 } else { 2495 dbuf_clear(db); 2496 } 2497 } else if (db->db_objset->os_evicting || 2498 arc_buf_eviction_needed(db->db_buf)) { 2499 dbuf_clear(db); 2500 } else { 2501 mutex_exit(&db->db_mtx); 2502 } 2503 } 2504 } else { 2505 mutex_exit(&db->db_mtx); 2506 } 2507} 2508 2509#pragma weak dmu_buf_refcount = dbuf_refcount 2510uint64_t 2511dbuf_refcount(dmu_buf_impl_t *db) 2512{ 2513 return (refcount_count(&db->db_holds)); 2514} 2515 2516void * 2517dmu_buf_replace_user(dmu_buf_t *db_fake, dmu_buf_user_t *old_user, 2518 dmu_buf_user_t *new_user) 2519{ 2520 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2521 2522 mutex_enter(&db->db_mtx); 2523 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2524 if (db->db_user == old_user) 2525 db->db_user = new_user; 2526 else 2527 old_user = db->db_user; 2528 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2529 mutex_exit(&db->db_mtx); 2530 2531 return (old_user); 2532} 2533 2534void * 2535dmu_buf_set_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2536{ 2537 return (dmu_buf_replace_user(db_fake, NULL, user)); 2538} 2539 2540void * 2541dmu_buf_set_user_ie(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2542{ 2543 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2544 2545 db->db_immediate_evict = TRUE; 2546 return (dmu_buf_set_user(db_fake, user)); 2547} 2548 2549void * 2550dmu_buf_remove_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2551{ 2552 return (dmu_buf_replace_user(db_fake, user, NULL)); 2553} 2554 2555void * 2556dmu_buf_get_user(dmu_buf_t *db_fake) 2557{ 2558 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2559 2560 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2561 return (db->db_user); 2562} 2563 2564void 2565dmu_buf_user_evict_wait() 2566{ 2567 taskq_wait(dbu_evict_taskq); 2568} 2569 2570boolean_t 2571dmu_buf_freeable(dmu_buf_t *dbuf) 2572{ 2573 boolean_t res = B_FALSE; 2574 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 2575 2576 if (db->db_blkptr) 2577 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset, 2578 db->db_blkptr, db->db_blkptr->blk_birth); 2579 2580 return (res); 2581} 2582 2583blkptr_t * 2584dmu_buf_get_blkptr(dmu_buf_t *db) 2585{ 2586 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; 2587 return (dbi->db_blkptr); 2588} 2589 2590static void 2591dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db) 2592{ 2593 /* ASSERT(dmu_tx_is_syncing(tx) */ 2594 ASSERT(MUTEX_HELD(&db->db_mtx)); 2595 2596 if (db->db_blkptr != NULL) 2597 return; 2598 2599 if (db->db_blkid == DMU_SPILL_BLKID) { 2600 db->db_blkptr = &dn->dn_phys->dn_spill; 2601 BP_ZERO(db->db_blkptr); 2602 return; 2603 } 2604 if (db->db_level == dn->dn_phys->dn_nlevels-1) { 2605 /* 2606 * This buffer was allocated at a time when there was 2607 * no available blkptrs from the dnode, or it was 2608 * inappropriate to hook it in (i.e., nlevels mis-match). 2609 */ 2610 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr); 2611 ASSERT(db->db_parent == NULL); 2612 db->db_parent = dn->dn_dbuf; 2613 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid]; 2614 DBUF_VERIFY(db); 2615 } else { 2616 dmu_buf_impl_t *parent = db->db_parent; 2617 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2618 2619 ASSERT(dn->dn_phys->dn_nlevels > 1); 2620 if (parent == NULL) { 2621 mutex_exit(&db->db_mtx); 2622 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2623 parent = dbuf_hold_level(dn, db->db_level + 1, 2624 db->db_blkid >> epbs, db); 2625 rw_exit(&dn->dn_struct_rwlock); 2626 mutex_enter(&db->db_mtx); 2627 db->db_parent = parent; 2628 } 2629 db->db_blkptr = (blkptr_t *)parent->db.db_data + 2630 (db->db_blkid & ((1ULL << epbs) - 1)); 2631 DBUF_VERIFY(db); 2632 } 2633} 2634 2635static void 2636dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2637{ 2638 dmu_buf_impl_t *db = dr->dr_dbuf; 2639 dnode_t *dn; 2640 zio_t *zio; 2641 2642 ASSERT(dmu_tx_is_syncing(tx)); 2643 2644 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2645 2646 mutex_enter(&db->db_mtx); 2647 2648 ASSERT(db->db_level > 0); 2649 DBUF_VERIFY(db); 2650 2651 /* Read the block if it hasn't been read yet. */ 2652 if (db->db_buf == NULL) { 2653 mutex_exit(&db->db_mtx); 2654 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); 2655 mutex_enter(&db->db_mtx); 2656 } 2657 ASSERT3U(db->db_state, ==, DB_CACHED); 2658 ASSERT(db->db_buf != NULL); 2659 2660 DB_DNODE_ENTER(db); 2661 dn = DB_DNODE(db); 2662 /* Indirect block size must match what the dnode thinks it is. */ 2663 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2664 dbuf_check_blkptr(dn, db); 2665 DB_DNODE_EXIT(db); 2666 2667 /* Provide the pending dirty record to child dbufs */ 2668 db->db_data_pending = dr; 2669 2670 mutex_exit(&db->db_mtx); 2671 dbuf_write(dr, db->db_buf, tx); 2672 2673 zio = dr->dr_zio; 2674 mutex_enter(&dr->dt.di.dr_mtx); 2675 dbuf_sync_list(&dr->dt.di.dr_children, db->db_level - 1, tx); 2676 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2677 mutex_exit(&dr->dt.di.dr_mtx); 2678 zio_nowait(zio); 2679} 2680 2681static void 2682dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2683{ 2684 arc_buf_t **datap = &dr->dt.dl.dr_data; 2685 dmu_buf_impl_t *db = dr->dr_dbuf; 2686 dnode_t *dn; 2687 objset_t *os; 2688 uint64_t txg = tx->tx_txg; 2689 2690 ASSERT(dmu_tx_is_syncing(tx)); 2691 2692 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2693 2694 mutex_enter(&db->db_mtx); 2695 /* 2696 * To be synced, we must be dirtied. But we 2697 * might have been freed after the dirty. 2698 */ 2699 if (db->db_state == DB_UNCACHED) { 2700 /* This buffer has been freed since it was dirtied */ 2701 ASSERT(db->db.db_data == NULL); 2702 } else if (db->db_state == DB_FILL) { 2703 /* This buffer was freed and is now being re-filled */ 2704 ASSERT(db->db.db_data != dr->dt.dl.dr_data); 2705 } else { 2706 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); 2707 } 2708 DBUF_VERIFY(db); 2709 2710 DB_DNODE_ENTER(db); 2711 dn = DB_DNODE(db); 2712 2713 if (db->db_blkid == DMU_SPILL_BLKID) { 2714 mutex_enter(&dn->dn_mtx); 2715 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR; 2716 mutex_exit(&dn->dn_mtx); 2717 } 2718 2719 /* 2720 * If this is a bonus buffer, simply copy the bonus data into the 2721 * dnode. It will be written out when the dnode is synced (and it 2722 * will be synced, since it must have been dirty for dbuf_sync to 2723 * be called). 2724 */ 2725 if (db->db_blkid == DMU_BONUS_BLKID) { 2726 dbuf_dirty_record_t **drp; 2727 2728 ASSERT(*datap != NULL); 2729 ASSERT0(db->db_level); 2730 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN); 2731 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen); 2732 DB_DNODE_EXIT(db); 2733 2734 if (*datap != db->db.db_data) { 2735 zio_buf_free(*datap, DN_MAX_BONUSLEN); 2736 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 2737 } 2738 db->db_data_pending = NULL; 2739 drp = &db->db_last_dirty; 2740 while (*drp != dr) 2741 drp = &(*drp)->dr_next; 2742 ASSERT(dr->dr_next == NULL); 2743 ASSERT(dr->dr_dbuf == db); 2744 *drp = dr->dr_next; 2745 if (dr->dr_dbuf->db_level != 0) { 2746 list_destroy(&dr->dt.di.dr_children); 2747 mutex_destroy(&dr->dt.di.dr_mtx); 2748 } 2749 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2750 ASSERT(db->db_dirtycnt > 0); 2751 db->db_dirtycnt -= 1; 2752 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2753 return; 2754 } 2755 2756 os = dn->dn_objset; 2757 2758 /* 2759 * This function may have dropped the db_mtx lock allowing a dmu_sync 2760 * operation to sneak in. As a result, we need to ensure that we 2761 * don't check the dr_override_state until we have returned from 2762 * dbuf_check_blkptr. 2763 */ 2764 dbuf_check_blkptr(dn, db); 2765 2766 /* 2767 * If this buffer is in the middle of an immediate write, 2768 * wait for the synchronous IO to complete. 2769 */ 2770 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) { 2771 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); 2772 cv_wait(&db->db_changed, &db->db_mtx); 2773 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN); 2774 } 2775 2776 if (db->db_state != DB_NOFILL && 2777 dn->dn_object != DMU_META_DNODE_OBJECT && 2778 refcount_count(&db->db_holds) > 1 && 2779 dr->dt.dl.dr_override_state != DR_OVERRIDDEN && 2780 *datap == db->db_buf) { 2781 /* 2782 * If this buffer is currently "in use" (i.e., there 2783 * are active holds and db_data still references it), 2784 * then make a copy before we start the write so that 2785 * any modifications from the open txg will not leak 2786 * into this write. 2787 * 2788 * NOTE: this copy does not need to be made for 2789 * objects only modified in the syncing context (e.g. 2790 * DNONE_DNODE blocks). 2791 */ 2792 int blksz = arc_buf_size(*datap); 2793 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2794 *datap = arc_buf_alloc(os->os_spa, blksz, db, type); 2795 bcopy(db->db.db_data, (*datap)->b_data, blksz); 2796 } 2797 db->db_data_pending = dr; 2798 2799 mutex_exit(&db->db_mtx); 2800 2801 dbuf_write(dr, *datap, tx); 2802 2803 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2804 if (dn->dn_object == DMU_META_DNODE_OBJECT) { 2805 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr); 2806 DB_DNODE_EXIT(db); 2807 } else { 2808 /* 2809 * Although zio_nowait() does not "wait for an IO", it does 2810 * initiate the IO. If this is an empty write it seems plausible 2811 * that the IO could actually be completed before the nowait 2812 * returns. We need to DB_DNODE_EXIT() first in case 2813 * zio_nowait() invalidates the dbuf. 2814 */ 2815 DB_DNODE_EXIT(db); 2816 zio_nowait(dr->dr_zio); 2817 } 2818} 2819 2820void 2821dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx) 2822{ 2823 dbuf_dirty_record_t *dr; 2824 2825 while (dr = list_head(list)) { 2826 if (dr->dr_zio != NULL) { 2827 /* 2828 * If we find an already initialized zio then we 2829 * are processing the meta-dnode, and we have finished. 2830 * The dbufs for all dnodes are put back on the list 2831 * during processing, so that we can zio_wait() 2832 * these IOs after initiating all child IOs. 2833 */ 2834 ASSERT3U(dr->dr_dbuf->db.db_object, ==, 2835 DMU_META_DNODE_OBJECT); 2836 break; 2837 } 2838 if (dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID && 2839 dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) { 2840 VERIFY3U(dr->dr_dbuf->db_level, ==, level); 2841 } 2842 list_remove(list, dr); 2843 if (dr->dr_dbuf->db_level > 0) 2844 dbuf_sync_indirect(dr, tx); 2845 else 2846 dbuf_sync_leaf(dr, tx); 2847 } 2848} 2849 2850/* ARGSUSED */ 2851static void 2852dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb) 2853{ 2854 dmu_buf_impl_t *db = vdb; 2855 dnode_t *dn; 2856 blkptr_t *bp = zio->io_bp; 2857 blkptr_t *bp_orig = &zio->io_bp_orig; 2858 spa_t *spa = zio->io_spa; 2859 int64_t delta; 2860 uint64_t fill = 0; 2861 int i; 2862 2863 ASSERT3P(db->db_blkptr, ==, bp); 2864 2865 DB_DNODE_ENTER(db); 2866 dn = DB_DNODE(db); 2867 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig); 2868 dnode_diduse_space(dn, delta - zio->io_prev_space_delta); 2869 zio->io_prev_space_delta = delta; 2870 2871 if (bp->blk_birth != 0) { 2872 ASSERT((db->db_blkid != DMU_SPILL_BLKID && 2873 BP_GET_TYPE(bp) == dn->dn_type) || 2874 (db->db_blkid == DMU_SPILL_BLKID && 2875 BP_GET_TYPE(bp) == dn->dn_bonustype) || 2876 BP_IS_EMBEDDED(bp)); 2877 ASSERT(BP_GET_LEVEL(bp) == db->db_level); 2878 } 2879 2880 mutex_enter(&db->db_mtx); 2881 2882#ifdef ZFS_DEBUG 2883 if (db->db_blkid == DMU_SPILL_BLKID) { 2884 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2885 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2886 db->db_blkptr == &dn->dn_phys->dn_spill); 2887 } 2888#endif 2889 2890 if (db->db_level == 0) { 2891 mutex_enter(&dn->dn_mtx); 2892 if (db->db_blkid > dn->dn_phys->dn_maxblkid && 2893 db->db_blkid != DMU_SPILL_BLKID) 2894 dn->dn_phys->dn_maxblkid = db->db_blkid; 2895 mutex_exit(&dn->dn_mtx); 2896 2897 if (dn->dn_type == DMU_OT_DNODE) { 2898 dnode_phys_t *dnp = db->db.db_data; 2899 for (i = db->db.db_size >> DNODE_SHIFT; i > 0; 2900 i--, dnp++) { 2901 if (dnp->dn_type != DMU_OT_NONE) 2902 fill++; 2903 } 2904 } else { 2905 if (BP_IS_HOLE(bp)) { 2906 fill = 0; 2907 } else { 2908 fill = 1; 2909 } 2910 } 2911 } else { 2912 blkptr_t *ibp = db->db.db_data; 2913 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2914 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) { 2915 if (BP_IS_HOLE(ibp)) 2916 continue; 2917 fill += BP_GET_FILL(ibp); 2918 } 2919 } 2920 DB_DNODE_EXIT(db); 2921 2922 if (!BP_IS_EMBEDDED(bp)) 2923 bp->blk_fill = fill; 2924 2925 mutex_exit(&db->db_mtx); 2926} 2927 2928/* 2929 * The SPA will call this callback several times for each zio - once 2930 * for every physical child i/o (zio->io_phys_children times). This 2931 * allows the DMU to monitor the progress of each logical i/o. For example, 2932 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z 2933 * block. There may be a long delay before all copies/fragments are completed, 2934 * so this callback allows us to retire dirty space gradually, as the physical 2935 * i/os complete. 2936 */ 2937/* ARGSUSED */ 2938static void 2939dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg) 2940{ 2941 dmu_buf_impl_t *db = arg; 2942 objset_t *os = db->db_objset; 2943 dsl_pool_t *dp = dmu_objset_pool(os); 2944 dbuf_dirty_record_t *dr; 2945 int delta = 0; 2946 2947 dr = db->db_data_pending; 2948 ASSERT3U(dr->dr_txg, ==, zio->io_txg); 2949 2950 /* 2951 * The callback will be called io_phys_children times. Retire one 2952 * portion of our dirty space each time we are called. Any rounding 2953 * error will be cleaned up by dsl_pool_sync()'s call to 2954 * dsl_pool_undirty_space(). 2955 */ 2956 delta = dr->dr_accounted / zio->io_phys_children; 2957 dsl_pool_undirty_space(dp, delta, zio->io_txg); 2958} 2959 2960/* ARGSUSED */ 2961static void 2962dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb) 2963{ 2964 dmu_buf_impl_t *db = vdb; 2965 blkptr_t *bp_orig = &zio->io_bp_orig; 2966 blkptr_t *bp = db->db_blkptr; 2967 objset_t *os = db->db_objset; 2968 dmu_tx_t *tx = os->os_synctx; 2969 dbuf_dirty_record_t **drp, *dr; 2970 2971 ASSERT0(zio->io_error); 2972 ASSERT(db->db_blkptr == bp); 2973 2974 /* 2975 * For nopwrites and rewrites we ensure that the bp matches our 2976 * original and bypass all the accounting. 2977 */ 2978 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) { 2979 ASSERT(BP_EQUAL(bp, bp_orig)); 2980 } else { 2981 dsl_dataset_t *ds = os->os_dsl_dataset; 2982 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE); 2983 dsl_dataset_block_born(ds, bp, tx); 2984 } 2985 2986 mutex_enter(&db->db_mtx); 2987 2988 DBUF_VERIFY(db); 2989 2990 drp = &db->db_last_dirty; 2991 while ((dr = *drp) != db->db_data_pending) 2992 drp = &dr->dr_next; 2993 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2994 ASSERT(dr->dr_dbuf == db); 2995 ASSERT(dr->dr_next == NULL); 2996 *drp = dr->dr_next; 2997 2998#ifdef ZFS_DEBUG 2999 if (db->db_blkid == DMU_SPILL_BLKID) { 3000 dnode_t *dn; 3001 3002 DB_DNODE_ENTER(db); 3003 dn = DB_DNODE(db); 3004 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 3005 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 3006 db->db_blkptr == &dn->dn_phys->dn_spill); 3007 DB_DNODE_EXIT(db); 3008 } 3009#endif 3010 3011 if (db->db_level == 0) { 3012 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 3013 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN); 3014 if (db->db_state != DB_NOFILL) { 3015 if (dr->dt.dl.dr_data != db->db_buf) 3016 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 3017 db)); 3018 else if (!arc_released(db->db_buf)) 3019 arc_set_callback(db->db_buf, dbuf_do_evict, db); 3020 } 3021 } else { 3022 dnode_t *dn; 3023 3024 DB_DNODE_ENTER(db); 3025 dn = DB_DNODE(db); 3026 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 3027 ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift); 3028 if (!BP_IS_HOLE(db->db_blkptr)) { 3029 int epbs = 3030 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 3031 ASSERT3U(db->db_blkid, <=, 3032 dn->dn_phys->dn_maxblkid >> (db->db_level * epbs)); 3033 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, 3034 db->db.db_size); 3035 if (!arc_released(db->db_buf)) 3036 arc_set_callback(db->db_buf, dbuf_do_evict, db); 3037 } 3038 DB_DNODE_EXIT(db); 3039 mutex_destroy(&dr->dt.di.dr_mtx); 3040 list_destroy(&dr->dt.di.dr_children); 3041 } 3042 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 3043 3044 cv_broadcast(&db->db_changed); 3045 ASSERT(db->db_dirtycnt > 0); 3046 db->db_dirtycnt -= 1; 3047 db->db_data_pending = NULL; 3048 dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg); 3049} 3050 3051static void 3052dbuf_write_nofill_ready(zio_t *zio) 3053{ 3054 dbuf_write_ready(zio, NULL, zio->io_private); 3055} 3056 3057static void 3058dbuf_write_nofill_done(zio_t *zio) 3059{ 3060 dbuf_write_done(zio, NULL, zio->io_private); 3061} 3062 3063static void 3064dbuf_write_override_ready(zio_t *zio) 3065{ 3066 dbuf_dirty_record_t *dr = zio->io_private; 3067 dmu_buf_impl_t *db = dr->dr_dbuf; 3068 3069 dbuf_write_ready(zio, NULL, db); 3070} 3071 3072static void 3073dbuf_write_override_done(zio_t *zio) 3074{ 3075 dbuf_dirty_record_t *dr = zio->io_private; 3076 dmu_buf_impl_t *db = dr->dr_dbuf; 3077 blkptr_t *obp = &dr->dt.dl.dr_overridden_by; 3078 3079 mutex_enter(&db->db_mtx); 3080 if (!BP_EQUAL(zio->io_bp, obp)) { 3081 if (!BP_IS_HOLE(obp)) 3082 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp); 3083 arc_release(dr->dt.dl.dr_data, db); 3084 } 3085 mutex_exit(&db->db_mtx); 3086 3087 dbuf_write_done(zio, NULL, db); 3088} 3089 3090/* Issue I/O to commit a dirty buffer to disk. */ 3091static void 3092dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) 3093{ 3094 dmu_buf_impl_t *db = dr->dr_dbuf; 3095 dnode_t *dn; 3096 objset_t *os; 3097 dmu_buf_impl_t *parent = db->db_parent; 3098 uint64_t txg = tx->tx_txg; 3099 zbookmark_phys_t zb; 3100 zio_prop_t zp; 3101 zio_t *zio; 3102 int wp_flag = 0; 3103 3104 DB_DNODE_ENTER(db); 3105 dn = DB_DNODE(db); 3106 os = dn->dn_objset; 3107 3108 if (db->db_state != DB_NOFILL) { 3109 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) { 3110 /* 3111 * Private object buffers are released here rather 3112 * than in dbuf_dirty() since they are only modified 3113 * in the syncing context and we don't want the 3114 * overhead of making multiple copies of the data. 3115 */ 3116 if (BP_IS_HOLE(db->db_blkptr)) { 3117 arc_buf_thaw(data); 3118 } else { 3119 dbuf_release_bp(db); 3120 } 3121 } 3122 } 3123 3124 if (parent != dn->dn_dbuf) { 3125 /* Our parent is an indirect block. */ 3126 /* We have a dirty parent that has been scheduled for write. */ 3127 ASSERT(parent && parent->db_data_pending); 3128 /* Our parent's buffer is one level closer to the dnode. */ 3129 ASSERT(db->db_level == parent->db_level-1); 3130 /* 3131 * We're about to modify our parent's db_data by modifying 3132 * our block pointer, so the parent must be released. 3133 */ 3134 ASSERT(arc_released(parent->db_buf)); 3135 zio = parent->db_data_pending->dr_zio; 3136 } else { 3137 /* Our parent is the dnode itself. */ 3138 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && 3139 db->db_blkid != DMU_SPILL_BLKID) || 3140 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); 3141 if (db->db_blkid != DMU_SPILL_BLKID) 3142 ASSERT3P(db->db_blkptr, ==, 3143 &dn->dn_phys->dn_blkptr[db->db_blkid]); 3144 zio = dn->dn_zio; 3145 } 3146 3147 ASSERT(db->db_level == 0 || data == db->db_buf); 3148 ASSERT3U(db->db_blkptr->blk_birth, <=, txg); 3149 ASSERT(zio); 3150 3151 SET_BOOKMARK(&zb, os->os_dsl_dataset ? 3152 os->os_dsl_dataset->ds_object : DMU_META_OBJSET, 3153 db->db.db_object, db->db_level, db->db_blkid); 3154 3155 if (db->db_blkid == DMU_SPILL_BLKID) 3156 wp_flag = WP_SPILL; 3157 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0; 3158 3159 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp); 3160 DB_DNODE_EXIT(db); 3161 3162 if (db->db_level == 0 && 3163 dr->dt.dl.dr_override_state == DR_OVERRIDDEN) { 3164 /* 3165 * The BP for this block has been provided by open context 3166 * (by dmu_sync() or dmu_buf_write_embedded()). 3167 */ 3168 void *contents = (data != NULL) ? data->b_data : NULL; 3169 3170 dr->dr_zio = zio_write(zio, os->os_spa, txg, 3171 db->db_blkptr, contents, db->db.db_size, &zp, 3172 dbuf_write_override_ready, NULL, dbuf_write_override_done, 3173 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 3174 mutex_enter(&db->db_mtx); 3175 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 3176 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by, 3177 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite); 3178 mutex_exit(&db->db_mtx); 3179 } else if (db->db_state == DB_NOFILL) { 3180 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF || 3181 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY); 3182 dr->dr_zio = zio_write(zio, os->os_spa, txg, 3183 db->db_blkptr, NULL, db->db.db_size, &zp, 3184 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db, 3185 ZIO_PRIORITY_ASYNC_WRITE, 3186 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb); 3187 } else { 3188 ASSERT(arc_released(data)); 3189 dr->dr_zio = arc_write(zio, os->os_spa, txg, 3190 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), 3191 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready, 3192 dbuf_write_physdone, dbuf_write_done, db, 3193 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 3194 } 3195} 3196