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 * Copyright (c) 2014 Integros [integros.com] 29 */ 30 31 #include <sys/zfs_context.h> 32 #include <sys/dmu.h> 33 #include <sys/dmu_send.h> 34 #include <sys/dmu_impl.h> 35 #include <sys/dbuf.h> 36 #include <sys/dmu_objset.h> 37 #include <sys/dsl_dataset.h> 38 #include <sys/dsl_dir.h> 39 #include <sys/dmu_tx.h> 40 #include <sys/spa.h> 41 #include <sys/zio.h> 42 #include <sys/dmu_zfetch.h> 43 #include <sys/sa.h> 44 #include <sys/sa_impl.h> 45 #include <sys/zfeature.h> 46 #include <sys/blkptr.h> 47 #include <sys/range_tree.h> 48 49 /* 50 * Number of times that zfs_free_range() took the slow path while doing 51 * a zfs receive. A nonzero value indicates a potential performance problem. 52 */ 53 uint64_t zfs_free_range_recv_miss; 54 55 static void dbuf_destroy(dmu_buf_impl_t *db); 56 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 57 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx); 58 59 #ifndef __lint 60 extern inline void dmu_buf_init_user(dmu_buf_user_t *dbu, 61 dmu_buf_evict_func_t *evict_func_sync, 62 dmu_buf_evict_func_t *evict_func_async, 63 dmu_buf_t **clear_on_evict_dbufp); 64 #endif /* ! __lint */ 65 66 /* 67 * Global data structures and functions for the dbuf cache. 68 */ 69 static kmem_cache_t *dbuf_cache; 70 static taskq_t *dbu_evict_taskq; 71 72 /* ARGSUSED */ 73 static int 74 dbuf_cons(void *vdb, void *unused, int kmflag) 75 { 76 dmu_buf_impl_t *db = vdb; 77 bzero(db, sizeof (dmu_buf_impl_t)); 78 79 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL); 80 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL); 81 refcount_create(&db->db_holds); 82 83 return (0); 84 } 85 86 /* ARGSUSED */ 87 static void 88 dbuf_dest(void *vdb, void *unused) 89 { 90 dmu_buf_impl_t *db = vdb; 91 mutex_destroy(&db->db_mtx); 92 cv_destroy(&db->db_changed); 93 refcount_destroy(&db->db_holds); 94 } 95 96 /* 97 * dbuf hash table routines 98 */ 99 static dbuf_hash_table_t dbuf_hash_table; 100 101 static uint64_t dbuf_hash_count; 102 103 static uint64_t 104 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid) 105 { 106 uintptr_t osv = (uintptr_t)os; 107 uint64_t crc = -1ULL; 108 109 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); 110 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF]; 111 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF]; 112 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF]; 113 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF]; 114 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF]; 115 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF]; 116 117 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16); 118 119 return (crc); 120 } 121 122 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid); 123 124 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \ 125 ((dbuf)->db.db_object == (obj) && \ 126 (dbuf)->db_objset == (os) && \ 127 (dbuf)->db_level == (level) && \ 128 (dbuf)->db_blkid == (blkid)) 129 130 dmu_buf_impl_t * 131 dbuf_find(objset_t *os, uint64_t obj, uint8_t level, uint64_t blkid) 132 { 133 dbuf_hash_table_t *h = &dbuf_hash_table; 134 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 135 uint64_t idx = hv & h->hash_table_mask; 136 dmu_buf_impl_t *db; 137 138 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 139 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) { 140 if (DBUF_EQUAL(db, os, obj, level, blkid)) { 141 mutex_enter(&db->db_mtx); 142 if (db->db_state != DB_EVICTING) { 143 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 144 return (db); 145 } 146 mutex_exit(&db->db_mtx); 147 } 148 } 149 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 150 return (NULL); 151 } 152 153 static dmu_buf_impl_t * 154 dbuf_find_bonus(objset_t *os, uint64_t object) 155 { 156 dnode_t *dn; 157 dmu_buf_impl_t *db = NULL; 158 159 if (dnode_hold(os, object, FTAG, &dn) == 0) { 160 rw_enter(&dn->dn_struct_rwlock, RW_READER); 161 if (dn->dn_bonus != NULL) { 162 db = dn->dn_bonus; 163 mutex_enter(&db->db_mtx); 164 } 165 rw_exit(&dn->dn_struct_rwlock); 166 dnode_rele(dn, FTAG); 167 } 168 return (db); 169 } 170 171 /* 172 * Insert an entry into the hash table. If there is already an element 173 * equal to elem in the hash table, then the already existing element 174 * will be returned and the new element will not be inserted. 175 * Otherwise returns NULL. 176 */ 177 static dmu_buf_impl_t * 178 dbuf_hash_insert(dmu_buf_impl_t *db) 179 { 180 dbuf_hash_table_t *h = &dbuf_hash_table; 181 objset_t *os = db->db_objset; 182 uint64_t obj = db->db.db_object; 183 int level = db->db_level; 184 uint64_t blkid = db->db_blkid; 185 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 186 uint64_t idx = hv & h->hash_table_mask; 187 dmu_buf_impl_t *dbf; 188 189 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 190 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) { 191 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) { 192 mutex_enter(&dbf->db_mtx); 193 if (dbf->db_state != DB_EVICTING) { 194 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 195 return (dbf); 196 } 197 mutex_exit(&dbf->db_mtx); 198 } 199 } 200 201 mutex_enter(&db->db_mtx); 202 db->db_hash_next = h->hash_table[idx]; 203 h->hash_table[idx] = db; 204 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 205 atomic_inc_64(&dbuf_hash_count); 206 207 return (NULL); 208 } 209 210 /* 211 * Remove an entry from the hash table. It must be in the EVICTING state. 212 */ 213 static void 214 dbuf_hash_remove(dmu_buf_impl_t *db) 215 { 216 dbuf_hash_table_t *h = &dbuf_hash_table; 217 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object, 218 db->db_level, db->db_blkid); 219 uint64_t idx = hv & h->hash_table_mask; 220 dmu_buf_impl_t *dbf, **dbp; 221 222 /* 223 * We musn't hold db_mtx to maintain lock ordering: 224 * DBUF_HASH_MUTEX > db_mtx. 225 */ 226 ASSERT(refcount_is_zero(&db->db_holds)); 227 ASSERT(db->db_state == DB_EVICTING); 228 ASSERT(!MUTEX_HELD(&db->db_mtx)); 229 230 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 231 dbp = &h->hash_table[idx]; 232 while ((dbf = *dbp) != db) { 233 dbp = &dbf->db_hash_next; 234 ASSERT(dbf != NULL); 235 } 236 *dbp = db->db_hash_next; 237 db->db_hash_next = NULL; 238 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 239 atomic_dec_64(&dbuf_hash_count); 240 } 241 242 static arc_evict_func_t dbuf_do_evict; 243 244 typedef enum { 245 DBVU_EVICTING, 246 DBVU_NOT_EVICTING 247 } dbvu_verify_type_t; 248 249 static void 250 dbuf_verify_user(dmu_buf_impl_t *db, dbvu_verify_type_t verify_type) 251 { 252 #ifdef ZFS_DEBUG 253 int64_t holds; 254 255 if (db->db_user == NULL) 256 return; 257 258 /* Only data blocks support the attachment of user data. */ 259 ASSERT(db->db_level == 0); 260 261 /* Clients must resolve a dbuf before attaching user data. */ 262 ASSERT(db->db.db_data != NULL); 263 ASSERT3U(db->db_state, ==, DB_CACHED); 264 265 holds = refcount_count(&db->db_holds); 266 if (verify_type == DBVU_EVICTING) { 267 /* 268 * Immediate eviction occurs when holds == dirtycnt. 269 * For normal eviction buffers, holds is zero on 270 * eviction, except when dbuf_fix_old_data() calls 271 * dbuf_clear_data(). However, the hold count can grow 272 * during eviction even though db_mtx is held (see 273 * dmu_bonus_hold() for an example), so we can only 274 * test the generic invariant that holds >= dirtycnt. 275 */ 276 ASSERT3U(holds, >=, db->db_dirtycnt); 277 } else { 278 if (db->db_user_immediate_evict == TRUE) 279 ASSERT3U(holds, >=, db->db_dirtycnt); 280 else 281 ASSERT3U(holds, >, 0); 282 } 283 #endif 284 } 285 286 static void 287 dbuf_evict_user(dmu_buf_impl_t *db) 288 { 289 dmu_buf_user_t *dbu = db->db_user; 290 291 ASSERT(MUTEX_HELD(&db->db_mtx)); 292 293 if (dbu == NULL) 294 return; 295 296 dbuf_verify_user(db, DBVU_EVICTING); 297 db->db_user = NULL; 298 299 #ifdef ZFS_DEBUG 300 if (dbu->dbu_clear_on_evict_dbufp != NULL) 301 *dbu->dbu_clear_on_evict_dbufp = NULL; 302 #endif 303 304 /* 305 * There are two eviction callbacks - one that we call synchronously 306 * and one that we invoke via a taskq. The async one is useful for 307 * avoiding lock order reversals and limiting stack depth. 308 * 309 * Note that if we have a sync callback but no async callback, 310 * it's likely that the sync callback will free the structure 311 * containing the dbu. In that case we need to take care to not 312 * dereference dbu after calling the sync evict func. 313 */ 314 boolean_t has_async = (dbu->dbu_evict_func_async != NULL); 315 316 if (dbu->dbu_evict_func_sync != NULL) 317 dbu->dbu_evict_func_sync(dbu); 318 319 if (has_async) { 320 taskq_dispatch_ent(dbu_evict_taskq, dbu->dbu_evict_func_async, 321 dbu, 0, &dbu->dbu_tqent); 322 } 323 } 324 325 boolean_t 326 dbuf_is_metadata(dmu_buf_impl_t *db) 327 { 328 if (db->db_level > 0) { 329 return (B_TRUE); 330 } else { 331 boolean_t is_metadata; 332 333 DB_DNODE_ENTER(db); 334 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type); 335 DB_DNODE_EXIT(db); 336 337 return (is_metadata); 338 } 339 } 340 341 void 342 dbuf_evict(dmu_buf_impl_t *db) 343 { 344 ASSERT(MUTEX_HELD(&db->db_mtx)); 345 ASSERT(db->db_buf == NULL); 346 ASSERT(db->db_data_pending == NULL); 347 348 dbuf_clear(db); 349 dbuf_destroy(db); 350 } 351 352 void 353 dbuf_init(void) 354 { 355 uint64_t hsize = 1ULL << 16; 356 dbuf_hash_table_t *h = &dbuf_hash_table; 357 int i; 358 359 /* 360 * The hash table is big enough to fill all of physical memory 361 * with an average 4K block size. The table will take up 362 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers). 363 */ 364 while (hsize * 4096 < physmem * PAGESIZE) 365 hsize <<= 1; 366 367 retry: 368 h->hash_table_mask = hsize - 1; 369 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP); 370 if (h->hash_table == NULL) { 371 /* XXX - we should really return an error instead of assert */ 372 ASSERT(hsize > (1ULL << 10)); 373 hsize >>= 1; 374 goto retry; 375 } 376 377 dbuf_cache = kmem_cache_create("dmu_buf_impl_t", 378 sizeof (dmu_buf_impl_t), 379 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0); 380 381 for (i = 0; i < DBUF_MUTEXES; i++) 382 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL); 383 384 /* 385 * All entries are queued via taskq_dispatch_ent(), so min/maxalloc 386 * configuration is not required. 387 */ 388 dbu_evict_taskq = taskq_create("dbu_evict", 1, minclsyspri, 0, 0, 0); 389 } 390 391 void 392 dbuf_fini(void) 393 { 394 dbuf_hash_table_t *h = &dbuf_hash_table; 395 int i; 396 397 for (i = 0; i < DBUF_MUTEXES; i++) 398 mutex_destroy(&h->hash_mutexes[i]); 399 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *)); 400 kmem_cache_destroy(dbuf_cache); 401 taskq_destroy(dbu_evict_taskq); 402 } 403 404 /* 405 * Other stuff. 406 */ 407 408 #ifdef ZFS_DEBUG 409 static void 410 dbuf_verify(dmu_buf_impl_t *db) 411 { 412 dnode_t *dn; 413 dbuf_dirty_record_t *dr; 414 415 ASSERT(MUTEX_HELD(&db->db_mtx)); 416 417 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY)) 418 return; 419 420 ASSERT(db->db_objset != NULL); 421 DB_DNODE_ENTER(db); 422 dn = DB_DNODE(db); 423 if (dn == NULL) { 424 ASSERT(db->db_parent == NULL); 425 ASSERT(db->db_blkptr == NULL); 426 } else { 427 ASSERT3U(db->db.db_object, ==, dn->dn_object); 428 ASSERT3P(db->db_objset, ==, dn->dn_objset); 429 ASSERT3U(db->db_level, <, dn->dn_nlevels); 430 ASSERT(db->db_blkid == DMU_BONUS_BLKID || 431 db->db_blkid == DMU_SPILL_BLKID || 432 !avl_is_empty(&dn->dn_dbufs)); 433 } 434 if (db->db_blkid == DMU_BONUS_BLKID) { 435 ASSERT(dn != NULL); 436 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 437 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID); 438 } else if (db->db_blkid == DMU_SPILL_BLKID) { 439 ASSERT(dn != NULL); 440 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 441 ASSERT0(db->db.db_offset); 442 } else { 443 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size); 444 } 445 446 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next) 447 ASSERT(dr->dr_dbuf == db); 448 449 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next) 450 ASSERT(dr->dr_dbuf == db); 451 452 /* 453 * We can't assert that db_size matches dn_datablksz because it 454 * can be momentarily different when another thread is doing 455 * dnode_set_blksz(). 456 */ 457 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) { 458 dr = db->db_data_pending; 459 /* 460 * It should only be modified in syncing context, so 461 * make sure we only have one copy of the data. 462 */ 463 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf); 464 } 465 466 /* verify db->db_blkptr */ 467 if (db->db_blkptr) { 468 if (db->db_parent == dn->dn_dbuf) { 469 /* db is pointed to by the dnode */ 470 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */ 471 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object)) 472 ASSERT(db->db_parent == NULL); 473 else 474 ASSERT(db->db_parent != NULL); 475 if (db->db_blkid != DMU_SPILL_BLKID) 476 ASSERT3P(db->db_blkptr, ==, 477 &dn->dn_phys->dn_blkptr[db->db_blkid]); 478 } else { 479 /* db is pointed to by an indirect block */ 480 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT; 481 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1); 482 ASSERT3U(db->db_parent->db.db_object, ==, 483 db->db.db_object); 484 /* 485 * dnode_grow_indblksz() can make this fail if we don't 486 * have the struct_rwlock. XXX indblksz no longer 487 * grows. safe to do this now? 488 */ 489 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 490 ASSERT3P(db->db_blkptr, ==, 491 ((blkptr_t *)db->db_parent->db.db_data + 492 db->db_blkid % epb)); 493 } 494 } 495 } 496 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) && 497 (db->db_buf == NULL || db->db_buf->b_data) && 498 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID && 499 db->db_state != DB_FILL && !dn->dn_free_txg) { 500 /* 501 * If the blkptr isn't set but they have nonzero data, 502 * it had better be dirty, otherwise we'll lose that 503 * data when we evict this buffer. 504 */ 505 if (db->db_dirtycnt == 0) { 506 uint64_t *buf = db->db.db_data; 507 int i; 508 509 for (i = 0; i < db->db.db_size >> 3; i++) { 510 ASSERT(buf[i] == 0); 511 } 512 } 513 } 514 DB_DNODE_EXIT(db); 515 } 516 #endif 517 518 static void 519 dbuf_clear_data(dmu_buf_impl_t *db) 520 { 521 ASSERT(MUTEX_HELD(&db->db_mtx)); 522 dbuf_evict_user(db); 523 db->db_buf = NULL; 524 db->db.db_data = NULL; 525 if (db->db_state != DB_NOFILL) 526 db->db_state = DB_UNCACHED; 527 } 528 529 static void 530 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf) 531 { 532 ASSERT(MUTEX_HELD(&db->db_mtx)); 533 ASSERT(buf != NULL); 534 535 db->db_buf = buf; 536 ASSERT(buf->b_data != NULL); 537 db->db.db_data = buf->b_data; 538 if (!arc_released(buf)) 539 arc_set_callback(buf, dbuf_do_evict, db); 540 } 541 542 /* 543 * Loan out an arc_buf for read. Return the loaned arc_buf. 544 */ 545 arc_buf_t * 546 dbuf_loan_arcbuf(dmu_buf_impl_t *db) 547 { 548 arc_buf_t *abuf; 549 550 mutex_enter(&db->db_mtx); 551 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) { 552 int blksz = db->db.db_size; 553 spa_t *spa = db->db_objset->os_spa; 554 555 mutex_exit(&db->db_mtx); 556 abuf = arc_loan_buf(spa, blksz); 557 bcopy(db->db.db_data, abuf->b_data, blksz); 558 } else { 559 abuf = db->db_buf; 560 arc_loan_inuse_buf(abuf, db); 561 dbuf_clear_data(db); 562 mutex_exit(&db->db_mtx); 563 } 564 return (abuf); 565 } 566 567 /* 568 * Calculate which level n block references the data at the level 0 offset 569 * provided. 570 */ 571 uint64_t 572 dbuf_whichblock(dnode_t *dn, int64_t level, uint64_t offset) 573 { 574 if (dn->dn_datablkshift != 0 && dn->dn_indblkshift != 0) { 575 /* 576 * The level n blkid is equal to the level 0 blkid divided by 577 * the number of level 0s in a level n block. 578 * 579 * The level 0 blkid is offset >> datablkshift = 580 * offset / 2^datablkshift. 581 * 582 * The number of level 0s in a level n is the number of block 583 * pointers in an indirect block, raised to the power of level. 584 * This is 2^(indblkshift - SPA_BLKPTRSHIFT)^level = 585 * 2^(level*(indblkshift - SPA_BLKPTRSHIFT)). 586 * 587 * Thus, the level n blkid is: offset / 588 * ((2^datablkshift)*(2^(level*(indblkshift - SPA_BLKPTRSHIFT))) 589 * = offset / 2^(datablkshift + level * 590 * (indblkshift - SPA_BLKPTRSHIFT)) 591 * = offset >> (datablkshift + level * 592 * (indblkshift - SPA_BLKPTRSHIFT)) 593 */ 594 return (offset >> (dn->dn_datablkshift + level * 595 (dn->dn_indblkshift - SPA_BLKPTRSHIFT))); 596 } else { 597 ASSERT3U(offset, <, dn->dn_datablksz); 598 return (0); 599 } 600 } 601 602 static void 603 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb) 604 { 605 dmu_buf_impl_t *db = vdb; 606 607 mutex_enter(&db->db_mtx); 608 ASSERT3U(db->db_state, ==, DB_READ); 609 /* 610 * All reads are synchronous, so we must have a hold on the dbuf 611 */ 612 ASSERT(refcount_count(&db->db_holds) > 0); 613 ASSERT(db->db_buf == NULL); 614 ASSERT(db->db.db_data == NULL); 615 if (db->db_level == 0 && db->db_freed_in_flight) { 616 /* we were freed in flight; disregard any error */ 617 arc_release(buf, db); 618 bzero(buf->b_data, db->db.db_size); 619 arc_buf_freeze(buf); 620 db->db_freed_in_flight = FALSE; 621 dbuf_set_data(db, buf); 622 db->db_state = DB_CACHED; 623 } else if (zio == NULL || zio->io_error == 0) { 624 dbuf_set_data(db, buf); 625 db->db_state = DB_CACHED; 626 } else { 627 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 628 ASSERT3P(db->db_buf, ==, NULL); 629 VERIFY(arc_buf_remove_ref(buf, db)); 630 db->db_state = DB_UNCACHED; 631 } 632 cv_broadcast(&db->db_changed); 633 dbuf_rele_and_unlock(db, NULL); 634 } 635 636 static void 637 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) 638 { 639 dnode_t *dn; 640 zbookmark_phys_t zb; 641 arc_flags_t aflags = ARC_FLAG_NOWAIT; 642 643 DB_DNODE_ENTER(db); 644 dn = DB_DNODE(db); 645 ASSERT(!refcount_is_zero(&db->db_holds)); 646 /* We need the struct_rwlock to prevent db_blkptr from changing. */ 647 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 648 ASSERT(MUTEX_HELD(&db->db_mtx)); 649 ASSERT(db->db_state == DB_UNCACHED); 650 ASSERT(db->db_buf == NULL); 651 652 if (db->db_blkid == DMU_BONUS_BLKID) { 653 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen); 654 655 ASSERT3U(bonuslen, <=, db->db.db_size); 656 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN); 657 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 658 if (bonuslen < DN_MAX_BONUSLEN) 659 bzero(db->db.db_data, DN_MAX_BONUSLEN); 660 if (bonuslen) 661 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen); 662 DB_DNODE_EXIT(db); 663 db->db_state = DB_CACHED; 664 mutex_exit(&db->db_mtx); 665 return; 666 } 667 668 /* 669 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync() 670 * processes the delete record and clears the bp while we are waiting 671 * for the dn_mtx (resulting in a "no" from block_freed). 672 */ 673 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) || 674 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) || 675 BP_IS_HOLE(db->db_blkptr)))) { 676 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 677 678 DB_DNODE_EXIT(db); 679 dbuf_set_data(db, arc_buf_alloc(db->db_objset->os_spa, 680 db->db.db_size, db, type)); 681 bzero(db->db.db_data, db->db.db_size); 682 db->db_state = DB_CACHED; 683 mutex_exit(&db->db_mtx); 684 return; 685 } 686 687 DB_DNODE_EXIT(db); 688 689 db->db_state = DB_READ; 690 mutex_exit(&db->db_mtx); 691 692 if (DBUF_IS_L2CACHEABLE(db)) 693 aflags |= ARC_FLAG_L2CACHE; 694 if (DBUF_IS_L2COMPRESSIBLE(db)) 695 aflags |= ARC_FLAG_L2COMPRESS; 696 697 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ? 698 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET, 699 db->db.db_object, db->db_level, db->db_blkid); 700 701 dbuf_add_ref(db, NULL); 702 703 (void) arc_read(zio, db->db_objset->os_spa, db->db_blkptr, 704 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ, 705 (flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED, 706 &aflags, &zb); 707 } 708 709 int 710 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) 711 { 712 int err = 0; 713 boolean_t havepzio = (zio != NULL); 714 boolean_t prefetch; 715 dnode_t *dn; 716 717 /* 718 * We don't have to hold the mutex to check db_state because it 719 * can't be freed while we have a hold on the buffer. 720 */ 721 ASSERT(!refcount_is_zero(&db->db_holds)); 722 723 if (db->db_state == DB_NOFILL) 724 return (SET_ERROR(EIO)); 725 726 DB_DNODE_ENTER(db); 727 dn = DB_DNODE(db); 728 if ((flags & DB_RF_HAVESTRUCT) == 0) 729 rw_enter(&dn->dn_struct_rwlock, RW_READER); 730 731 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 732 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL && 733 DBUF_IS_CACHEABLE(db); 734 735 mutex_enter(&db->db_mtx); 736 if (db->db_state == DB_CACHED) { 737 mutex_exit(&db->db_mtx); 738 if (prefetch) 739 dmu_zfetch(&dn->dn_zfetch, db->db_blkid, 1); 740 if ((flags & DB_RF_HAVESTRUCT) == 0) 741 rw_exit(&dn->dn_struct_rwlock); 742 DB_DNODE_EXIT(db); 743 } else if (db->db_state == DB_UNCACHED) { 744 spa_t *spa = dn->dn_objset->os_spa; 745 746 if (zio == NULL) 747 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL); 748 dbuf_read_impl(db, zio, flags); 749 750 /* dbuf_read_impl has dropped db_mtx for us */ 751 752 if (prefetch) 753 dmu_zfetch(&dn->dn_zfetch, db->db_blkid, 1); 754 755 if ((flags & DB_RF_HAVESTRUCT) == 0) 756 rw_exit(&dn->dn_struct_rwlock); 757 DB_DNODE_EXIT(db); 758 759 if (!havepzio) 760 err = zio_wait(zio); 761 } else { 762 /* 763 * Another reader came in while the dbuf was in flight 764 * between UNCACHED and CACHED. Either a writer will finish 765 * writing the buffer (sending the dbuf to CACHED) or the 766 * first reader's request will reach the read_done callback 767 * and send the dbuf to CACHED. Otherwise, a failure 768 * occurred and the dbuf went to UNCACHED. 769 */ 770 mutex_exit(&db->db_mtx); 771 if (prefetch) 772 dmu_zfetch(&dn->dn_zfetch, db->db_blkid, 1); 773 if ((flags & DB_RF_HAVESTRUCT) == 0) 774 rw_exit(&dn->dn_struct_rwlock); 775 DB_DNODE_EXIT(db); 776 777 /* Skip the wait per the caller's request. */ 778 mutex_enter(&db->db_mtx); 779 if ((flags & DB_RF_NEVERWAIT) == 0) { 780 while (db->db_state == DB_READ || 781 db->db_state == DB_FILL) { 782 ASSERT(db->db_state == DB_READ || 783 (flags & DB_RF_HAVESTRUCT) == 0); 784 DTRACE_PROBE2(blocked__read, dmu_buf_impl_t *, 785 db, zio_t *, zio); 786 cv_wait(&db->db_changed, &db->db_mtx); 787 } 788 if (db->db_state == DB_UNCACHED) 789 err = SET_ERROR(EIO); 790 } 791 mutex_exit(&db->db_mtx); 792 } 793 794 ASSERT(err || havepzio || db->db_state == DB_CACHED); 795 return (err); 796 } 797 798 static void 799 dbuf_noread(dmu_buf_impl_t *db) 800 { 801 ASSERT(!refcount_is_zero(&db->db_holds)); 802 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 803 mutex_enter(&db->db_mtx); 804 while (db->db_state == DB_READ || db->db_state == DB_FILL) 805 cv_wait(&db->db_changed, &db->db_mtx); 806 if (db->db_state == DB_UNCACHED) { 807 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 808 spa_t *spa = db->db_objset->os_spa; 809 810 ASSERT(db->db_buf == NULL); 811 ASSERT(db->db.db_data == NULL); 812 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type)); 813 db->db_state = DB_FILL; 814 } else if (db->db_state == DB_NOFILL) { 815 dbuf_clear_data(db); 816 } else { 817 ASSERT3U(db->db_state, ==, DB_CACHED); 818 } 819 mutex_exit(&db->db_mtx); 820 } 821 822 /* 823 * This is our just-in-time copy function. It makes a copy of 824 * buffers, that have been modified in a previous transaction 825 * group, before we modify them in the current active group. 826 * 827 * This function is used in two places: when we are dirtying a 828 * buffer for the first time in a txg, and when we are freeing 829 * a range in a dnode that includes this buffer. 830 * 831 * Note that when we are called from dbuf_free_range() we do 832 * not put a hold on the buffer, we just traverse the active 833 * dbuf list for the dnode. 834 */ 835 static void 836 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg) 837 { 838 dbuf_dirty_record_t *dr = db->db_last_dirty; 839 840 ASSERT(MUTEX_HELD(&db->db_mtx)); 841 ASSERT(db->db.db_data != NULL); 842 ASSERT(db->db_level == 0); 843 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT); 844 845 if (dr == NULL || 846 (dr->dt.dl.dr_data != 847 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf))) 848 return; 849 850 /* 851 * If the last dirty record for this dbuf has not yet synced 852 * and its referencing the dbuf data, either: 853 * reset the reference to point to a new copy, 854 * or (if there a no active holders) 855 * just null out the current db_data pointer. 856 */ 857 ASSERT(dr->dr_txg >= txg - 2); 858 if (db->db_blkid == DMU_BONUS_BLKID) { 859 /* Note that the data bufs here are zio_bufs */ 860 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN); 861 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 862 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN); 863 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) { 864 int size = db->db.db_size; 865 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 866 spa_t *spa = db->db_objset->os_spa; 867 868 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type); 869 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size); 870 } else { 871 dbuf_clear_data(db); 872 } 873 } 874 875 void 876 dbuf_unoverride(dbuf_dirty_record_t *dr) 877 { 878 dmu_buf_impl_t *db = dr->dr_dbuf; 879 blkptr_t *bp = &dr->dt.dl.dr_overridden_by; 880 uint64_t txg = dr->dr_txg; 881 882 ASSERT(MUTEX_HELD(&db->db_mtx)); 883 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC); 884 ASSERT(db->db_level == 0); 885 886 if (db->db_blkid == DMU_BONUS_BLKID || 887 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN) 888 return; 889 890 ASSERT(db->db_data_pending != dr); 891 892 /* free this block */ 893 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite) 894 zio_free(db->db_objset->os_spa, txg, bp); 895 896 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 897 dr->dt.dl.dr_nopwrite = B_FALSE; 898 899 /* 900 * Release the already-written buffer, so we leave it in 901 * a consistent dirty state. Note that all callers are 902 * modifying the buffer, so they will immediately do 903 * another (redundant) arc_release(). Therefore, leave 904 * the buf thawed to save the effort of freezing & 905 * immediately re-thawing it. 906 */ 907 arc_release(dr->dt.dl.dr_data, db); 908 } 909 910 /* 911 * Evict (if its unreferenced) or clear (if its referenced) any level-0 912 * data blocks in the free range, so that any future readers will find 913 * empty blocks. 914 * 915 * This is a no-op if the dataset is in the middle of an incremental 916 * receive; see comment below for details. 917 */ 918 void 919 dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, 920 dmu_tx_t *tx) 921 { 922 dmu_buf_impl_t db_search; 923 dmu_buf_impl_t *db, *db_next; 924 uint64_t txg = tx->tx_txg; 925 avl_index_t where; 926 927 if (end_blkid > dn->dn_maxblkid && (end_blkid != DMU_SPILL_BLKID)) 928 end_blkid = dn->dn_maxblkid; 929 dprintf_dnode(dn, "start=%llu end=%llu\n", start_blkid, end_blkid); 930 931 db_search.db_level = 0; 932 db_search.db_blkid = start_blkid; 933 db_search.db_state = DB_SEARCH; 934 935 mutex_enter(&dn->dn_dbufs_mtx); 936 if (start_blkid >= dn->dn_unlisted_l0_blkid) { 937 /* There can't be any dbufs in this range; no need to search. */ 938 #ifdef DEBUG 939 db = avl_find(&dn->dn_dbufs, &db_search, &where); 940 ASSERT3P(db, ==, NULL); 941 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 942 ASSERT(db == NULL || db->db_level > 0); 943 #endif 944 mutex_exit(&dn->dn_dbufs_mtx); 945 return; 946 } else if (dmu_objset_is_receiving(dn->dn_objset)) { 947 /* 948 * If we are receiving, we expect there to be no dbufs in 949 * the range to be freed, because receive modifies each 950 * block at most once, and in offset order. If this is 951 * not the case, it can lead to performance problems, 952 * so note that we unexpectedly took the slow path. 953 */ 954 atomic_inc_64(&zfs_free_range_recv_miss); 955 } 956 957 db = avl_find(&dn->dn_dbufs, &db_search, &where); 958 ASSERT3P(db, ==, NULL); 959 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 960 961 for (; db != NULL; db = db_next) { 962 db_next = AVL_NEXT(&dn->dn_dbufs, db); 963 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 964 965 if (db->db_level != 0 || db->db_blkid > end_blkid) { 966 break; 967 } 968 ASSERT3U(db->db_blkid, >=, start_blkid); 969 970 /* found a level 0 buffer in the range */ 971 mutex_enter(&db->db_mtx); 972 if (dbuf_undirty(db, tx)) { 973 /* mutex has been dropped and dbuf destroyed */ 974 continue; 975 } 976 977 if (db->db_state == DB_UNCACHED || 978 db->db_state == DB_NOFILL || 979 db->db_state == DB_EVICTING) { 980 ASSERT(db->db.db_data == NULL); 981 mutex_exit(&db->db_mtx); 982 continue; 983 } 984 if (db->db_state == DB_READ || db->db_state == DB_FILL) { 985 /* will be handled in dbuf_read_done or dbuf_rele */ 986 db->db_freed_in_flight = TRUE; 987 mutex_exit(&db->db_mtx); 988 continue; 989 } 990 if (refcount_count(&db->db_holds) == 0) { 991 ASSERT(db->db_buf); 992 dbuf_clear(db); 993 continue; 994 } 995 /* The dbuf is referenced */ 996 997 if (db->db_last_dirty != NULL) { 998 dbuf_dirty_record_t *dr = db->db_last_dirty; 999 1000 if (dr->dr_txg == txg) { 1001 /* 1002 * This buffer is "in-use", re-adjust the file 1003 * size to reflect that this buffer may 1004 * contain new data when we sync. 1005 */ 1006 if (db->db_blkid != DMU_SPILL_BLKID && 1007 db->db_blkid > dn->dn_maxblkid) 1008 dn->dn_maxblkid = db->db_blkid; 1009 dbuf_unoverride(dr); 1010 } else { 1011 /* 1012 * This dbuf is not dirty in the open context. 1013 * Either uncache it (if its not referenced in 1014 * the open context) or reset its contents to 1015 * empty. 1016 */ 1017 dbuf_fix_old_data(db, txg); 1018 } 1019 } 1020 /* clear the contents if its cached */ 1021 if (db->db_state == DB_CACHED) { 1022 ASSERT(db->db.db_data != NULL); 1023 arc_release(db->db_buf, db); 1024 bzero(db->db.db_data, db->db.db_size); 1025 arc_buf_freeze(db->db_buf); 1026 } 1027 1028 mutex_exit(&db->db_mtx); 1029 } 1030 mutex_exit(&dn->dn_dbufs_mtx); 1031 } 1032 1033 static int 1034 dbuf_block_freeable(dmu_buf_impl_t *db) 1035 { 1036 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset; 1037 uint64_t birth_txg = 0; 1038 1039 /* 1040 * We don't need any locking to protect db_blkptr: 1041 * If it's syncing, then db_last_dirty will be set 1042 * so we'll ignore db_blkptr. 1043 * 1044 * This logic ensures that only block births for 1045 * filled blocks are considered. 1046 */ 1047 ASSERT(MUTEX_HELD(&db->db_mtx)); 1048 if (db->db_last_dirty && (db->db_blkptr == NULL || 1049 !BP_IS_HOLE(db->db_blkptr))) { 1050 birth_txg = db->db_last_dirty->dr_txg; 1051 } else if (db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr)) { 1052 birth_txg = db->db_blkptr->blk_birth; 1053 } 1054 1055 /* 1056 * If this block don't exist or is in a snapshot, it can't be freed. 1057 * Don't pass the bp to dsl_dataset_block_freeable() since we 1058 * are holding the db_mtx lock and might deadlock if we are 1059 * prefetching a dedup-ed block. 1060 */ 1061 if (birth_txg != 0) 1062 return (ds == NULL || 1063 dsl_dataset_block_freeable(ds, NULL, birth_txg)); 1064 else 1065 return (B_FALSE); 1066 } 1067 1068 void 1069 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx) 1070 { 1071 arc_buf_t *buf, *obuf; 1072 int osize = db->db.db_size; 1073 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 1074 dnode_t *dn; 1075 1076 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1077 1078 DB_DNODE_ENTER(db); 1079 dn = DB_DNODE(db); 1080 1081 /* XXX does *this* func really need the lock? */ 1082 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 1083 1084 /* 1085 * This call to dmu_buf_will_dirty() with the dn_struct_rwlock held 1086 * is OK, because there can be no other references to the db 1087 * when we are changing its size, so no concurrent DB_FILL can 1088 * be happening. 1089 */ 1090 /* 1091 * XXX we should be doing a dbuf_read, checking the return 1092 * value and returning that up to our callers 1093 */ 1094 dmu_buf_will_dirty(&db->db, tx); 1095 1096 /* create the data buffer for the new block */ 1097 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type); 1098 1099 /* copy old block data to the new block */ 1100 obuf = db->db_buf; 1101 bcopy(obuf->b_data, buf->b_data, MIN(osize, size)); 1102 /* zero the remainder */ 1103 if (size > osize) 1104 bzero((uint8_t *)buf->b_data + osize, size - osize); 1105 1106 mutex_enter(&db->db_mtx); 1107 dbuf_set_data(db, buf); 1108 VERIFY(arc_buf_remove_ref(obuf, db)); 1109 db->db.db_size = size; 1110 1111 if (db->db_level == 0) { 1112 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 1113 db->db_last_dirty->dt.dl.dr_data = buf; 1114 } 1115 mutex_exit(&db->db_mtx); 1116 1117 dnode_willuse_space(dn, size-osize, tx); 1118 DB_DNODE_EXIT(db); 1119 } 1120 1121 void 1122 dbuf_release_bp(dmu_buf_impl_t *db) 1123 { 1124 objset_t *os = db->db_objset; 1125 1126 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os))); 1127 ASSERT(arc_released(os->os_phys_buf) || 1128 list_link_active(&os->os_dsl_dataset->ds_synced_link)); 1129 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf)); 1130 1131 (void) arc_release(db->db_buf, db); 1132 } 1133 1134 /* 1135 * We already have a dirty record for this TXG, and we are being 1136 * dirtied again. 1137 */ 1138 static void 1139 dbuf_redirty(dbuf_dirty_record_t *dr) 1140 { 1141 dmu_buf_impl_t *db = dr->dr_dbuf; 1142 1143 ASSERT(MUTEX_HELD(&db->db_mtx)); 1144 1145 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) { 1146 /* 1147 * If this buffer has already been written out, 1148 * we now need to reset its state. 1149 */ 1150 dbuf_unoverride(dr); 1151 if (db->db.db_object != DMU_META_DNODE_OBJECT && 1152 db->db_state != DB_NOFILL) { 1153 /* Already released on initial dirty, so just thaw. */ 1154 ASSERT(arc_released(db->db_buf)); 1155 arc_buf_thaw(db->db_buf); 1156 } 1157 } 1158 } 1159 1160 dbuf_dirty_record_t * 1161 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1162 { 1163 dnode_t *dn; 1164 objset_t *os; 1165 dbuf_dirty_record_t **drp, *dr; 1166 int drop_struct_lock = FALSE; 1167 boolean_t do_free_accounting = B_FALSE; 1168 int txgoff = tx->tx_txg & TXG_MASK; 1169 1170 ASSERT(tx->tx_txg != 0); 1171 ASSERT(!refcount_is_zero(&db->db_holds)); 1172 DMU_TX_DIRTY_BUF(tx, db); 1173 1174 DB_DNODE_ENTER(db); 1175 dn = DB_DNODE(db); 1176 /* 1177 * Shouldn't dirty a regular buffer in syncing context. Private 1178 * objects may be dirtied in syncing context, but only if they 1179 * were already pre-dirtied in open context. 1180 */ 1181 ASSERT(!dmu_tx_is_syncing(tx) || 1182 BP_IS_HOLE(dn->dn_objset->os_rootbp) || 1183 DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1184 dn->dn_objset->os_dsl_dataset == NULL); 1185 /* 1186 * We make this assert for private objects as well, but after we 1187 * check if we're already dirty. They are allowed to re-dirty 1188 * in syncing context. 1189 */ 1190 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1191 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1192 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1193 1194 mutex_enter(&db->db_mtx); 1195 /* 1196 * XXX make this true for indirects too? The problem is that 1197 * transactions created with dmu_tx_create_assigned() from 1198 * syncing context don't bother holding ahead. 1199 */ 1200 ASSERT(db->db_level != 0 || 1201 db->db_state == DB_CACHED || db->db_state == DB_FILL || 1202 db->db_state == DB_NOFILL); 1203 1204 mutex_enter(&dn->dn_mtx); 1205 /* 1206 * Don't set dirtyctx to SYNC if we're just modifying this as we 1207 * initialize the objset. 1208 */ 1209 if (dn->dn_dirtyctx == DN_UNDIRTIED && 1210 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) { 1211 dn->dn_dirtyctx = 1212 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN); 1213 ASSERT(dn->dn_dirtyctx_firstset == NULL); 1214 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP); 1215 } 1216 mutex_exit(&dn->dn_mtx); 1217 1218 if (db->db_blkid == DMU_SPILL_BLKID) 1219 dn->dn_have_spill = B_TRUE; 1220 1221 /* 1222 * If this buffer is already dirty, we're done. 1223 */ 1224 drp = &db->db_last_dirty; 1225 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg || 1226 db->db.db_object == DMU_META_DNODE_OBJECT); 1227 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg) 1228 drp = &dr->dr_next; 1229 if (dr && dr->dr_txg == tx->tx_txg) { 1230 DB_DNODE_EXIT(db); 1231 1232 dbuf_redirty(dr); 1233 mutex_exit(&db->db_mtx); 1234 return (dr); 1235 } 1236 1237 /* 1238 * Only valid if not already dirty. 1239 */ 1240 ASSERT(dn->dn_object == 0 || 1241 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1242 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1243 1244 ASSERT3U(dn->dn_nlevels, >, db->db_level); 1245 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) || 1246 dn->dn_phys->dn_nlevels > db->db_level || 1247 dn->dn_next_nlevels[txgoff] > db->db_level || 1248 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level || 1249 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level); 1250 1251 /* 1252 * We should only be dirtying in syncing context if it's the 1253 * mos or we're initializing the os or it's a special object. 1254 * However, we are allowed to dirty in syncing context provided 1255 * we already dirtied it in open context. Hence we must make 1256 * this assertion only if we're not already dirty. 1257 */ 1258 os = dn->dn_objset; 1259 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1260 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp)); 1261 ASSERT(db->db.db_size != 0); 1262 1263 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1264 1265 if (db->db_blkid != DMU_BONUS_BLKID) { 1266 /* 1267 * Update the accounting. 1268 * Note: we delay "free accounting" until after we drop 1269 * the db_mtx. This keeps us from grabbing other locks 1270 * (and possibly deadlocking) in bp_get_dsize() while 1271 * also holding the db_mtx. 1272 */ 1273 dnode_willuse_space(dn, db->db.db_size, tx); 1274 do_free_accounting = dbuf_block_freeable(db); 1275 } 1276 1277 /* 1278 * If this buffer is dirty in an old transaction group we need 1279 * to make a copy of it so that the changes we make in this 1280 * transaction group won't leak out when we sync the older txg. 1281 */ 1282 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP); 1283 if (db->db_level == 0) { 1284 void *data_old = db->db_buf; 1285 1286 if (db->db_state != DB_NOFILL) { 1287 if (db->db_blkid == DMU_BONUS_BLKID) { 1288 dbuf_fix_old_data(db, tx->tx_txg); 1289 data_old = db->db.db_data; 1290 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) { 1291 /* 1292 * Release the data buffer from the cache so 1293 * that we can modify it without impacting 1294 * possible other users of this cached data 1295 * block. Note that indirect blocks and 1296 * private objects are not released until the 1297 * syncing state (since they are only modified 1298 * then). 1299 */ 1300 arc_release(db->db_buf, db); 1301 dbuf_fix_old_data(db, tx->tx_txg); 1302 data_old = db->db_buf; 1303 } 1304 ASSERT(data_old != NULL); 1305 } 1306 dr->dt.dl.dr_data = data_old; 1307 } else { 1308 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL); 1309 list_create(&dr->dt.di.dr_children, 1310 sizeof (dbuf_dirty_record_t), 1311 offsetof(dbuf_dirty_record_t, dr_dirty_node)); 1312 } 1313 if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL) 1314 dr->dr_accounted = db->db.db_size; 1315 dr->dr_dbuf = db; 1316 dr->dr_txg = tx->tx_txg; 1317 dr->dr_next = *drp; 1318 *drp = dr; 1319 1320 /* 1321 * We could have been freed_in_flight between the dbuf_noread 1322 * and dbuf_dirty. We win, as though the dbuf_noread() had 1323 * happened after the free. 1324 */ 1325 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1326 db->db_blkid != DMU_SPILL_BLKID) { 1327 mutex_enter(&dn->dn_mtx); 1328 if (dn->dn_free_ranges[txgoff] != NULL) { 1329 range_tree_clear(dn->dn_free_ranges[txgoff], 1330 db->db_blkid, 1); 1331 } 1332 mutex_exit(&dn->dn_mtx); 1333 db->db_freed_in_flight = FALSE; 1334 } 1335 1336 /* 1337 * This buffer is now part of this txg 1338 */ 1339 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg); 1340 db->db_dirtycnt += 1; 1341 ASSERT3U(db->db_dirtycnt, <=, 3); 1342 1343 mutex_exit(&db->db_mtx); 1344 1345 if (db->db_blkid == DMU_BONUS_BLKID || 1346 db->db_blkid == DMU_SPILL_BLKID) { 1347 mutex_enter(&dn->dn_mtx); 1348 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1349 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1350 mutex_exit(&dn->dn_mtx); 1351 dnode_setdirty(dn, tx); 1352 DB_DNODE_EXIT(db); 1353 return (dr); 1354 } else if (do_free_accounting) { 1355 blkptr_t *bp = db->db_blkptr; 1356 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ? 1357 bp_get_dsize(os->os_spa, bp) : db->db.db_size; 1358 /* 1359 * This is only a guess -- if the dbuf is dirty 1360 * in a previous txg, we don't know how much 1361 * space it will use on disk yet. We should 1362 * really have the struct_rwlock to access 1363 * db_blkptr, but since this is just a guess, 1364 * it's OK if we get an odd answer. 1365 */ 1366 ddt_prefetch(os->os_spa, bp); 1367 dnode_willuse_space(dn, -willfree, tx); 1368 } 1369 1370 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 1371 rw_enter(&dn->dn_struct_rwlock, RW_READER); 1372 drop_struct_lock = TRUE; 1373 } 1374 1375 if (db->db_level == 0) { 1376 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock); 1377 ASSERT(dn->dn_maxblkid >= db->db_blkid); 1378 } 1379 1380 if (db->db_level+1 < dn->dn_nlevels) { 1381 dmu_buf_impl_t *parent = db->db_parent; 1382 dbuf_dirty_record_t *di; 1383 int parent_held = FALSE; 1384 1385 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) { 1386 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1387 1388 parent = dbuf_hold_level(dn, db->db_level+1, 1389 db->db_blkid >> epbs, FTAG); 1390 ASSERT(parent != NULL); 1391 parent_held = TRUE; 1392 } 1393 if (drop_struct_lock) 1394 rw_exit(&dn->dn_struct_rwlock); 1395 ASSERT3U(db->db_level+1, ==, parent->db_level); 1396 di = dbuf_dirty(parent, tx); 1397 if (parent_held) 1398 dbuf_rele(parent, FTAG); 1399 1400 mutex_enter(&db->db_mtx); 1401 /* 1402 * Since we've dropped the mutex, it's possible that 1403 * dbuf_undirty() might have changed this out from under us. 1404 */ 1405 if (db->db_last_dirty == dr || 1406 dn->dn_object == DMU_META_DNODE_OBJECT) { 1407 mutex_enter(&di->dt.di.dr_mtx); 1408 ASSERT3U(di->dr_txg, ==, tx->tx_txg); 1409 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1410 list_insert_tail(&di->dt.di.dr_children, dr); 1411 mutex_exit(&di->dt.di.dr_mtx); 1412 dr->dr_parent = di; 1413 } 1414 mutex_exit(&db->db_mtx); 1415 } else { 1416 ASSERT(db->db_level+1 == dn->dn_nlevels); 1417 ASSERT(db->db_blkid < dn->dn_nblkptr); 1418 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf); 1419 mutex_enter(&dn->dn_mtx); 1420 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1421 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1422 mutex_exit(&dn->dn_mtx); 1423 if (drop_struct_lock) 1424 rw_exit(&dn->dn_struct_rwlock); 1425 } 1426 1427 dnode_setdirty(dn, tx); 1428 DB_DNODE_EXIT(db); 1429 return (dr); 1430 } 1431 1432 /* 1433 * Undirty a buffer in the transaction group referenced by the given 1434 * transaction. Return whether this evicted the dbuf. 1435 */ 1436 static boolean_t 1437 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1438 { 1439 dnode_t *dn; 1440 uint64_t txg = tx->tx_txg; 1441 dbuf_dirty_record_t *dr, **drp; 1442 1443 ASSERT(txg != 0); 1444 1445 /* 1446 * Due to our use of dn_nlevels below, this can only be called 1447 * in open context, unless we are operating on the MOS. 1448 * From syncing context, dn_nlevels may be different from the 1449 * dn_nlevels used when dbuf was dirtied. 1450 */ 1451 ASSERT(db->db_objset == 1452 dmu_objset_pool(db->db_objset)->dp_meta_objset || 1453 txg != spa_syncing_txg(dmu_objset_spa(db->db_objset))); 1454 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1455 ASSERT0(db->db_level); 1456 ASSERT(MUTEX_HELD(&db->db_mtx)); 1457 1458 /* 1459 * If this buffer is not dirty, we're done. 1460 */ 1461 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next) 1462 if (dr->dr_txg <= txg) 1463 break; 1464 if (dr == NULL || dr->dr_txg < txg) 1465 return (B_FALSE); 1466 ASSERT(dr->dr_txg == txg); 1467 ASSERT(dr->dr_dbuf == db); 1468 1469 DB_DNODE_ENTER(db); 1470 dn = DB_DNODE(db); 1471 1472 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1473 1474 ASSERT(db->db.db_size != 0); 1475 1476 dsl_pool_undirty_space(dmu_objset_pool(dn->dn_objset), 1477 dr->dr_accounted, txg); 1478 1479 *drp = dr->dr_next; 1480 1481 /* 1482 * Note that there are three places in dbuf_dirty() 1483 * where this dirty record may be put on a list. 1484 * Make sure to do a list_remove corresponding to 1485 * every one of those list_insert calls. 1486 */ 1487 if (dr->dr_parent) { 1488 mutex_enter(&dr->dr_parent->dt.di.dr_mtx); 1489 list_remove(&dr->dr_parent->dt.di.dr_children, dr); 1490 mutex_exit(&dr->dr_parent->dt.di.dr_mtx); 1491 } else if (db->db_blkid == DMU_SPILL_BLKID || 1492 db->db_level + 1 == dn->dn_nlevels) { 1493 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf); 1494 mutex_enter(&dn->dn_mtx); 1495 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr); 1496 mutex_exit(&dn->dn_mtx); 1497 } 1498 DB_DNODE_EXIT(db); 1499 1500 if (db->db_state != DB_NOFILL) { 1501 dbuf_unoverride(dr); 1502 1503 ASSERT(db->db_buf != NULL); 1504 ASSERT(dr->dt.dl.dr_data != NULL); 1505 if (dr->dt.dl.dr_data != db->db_buf) 1506 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db)); 1507 } 1508 1509 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 1510 1511 ASSERT(db->db_dirtycnt > 0); 1512 db->db_dirtycnt -= 1; 1513 1514 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) { 1515 arc_buf_t *buf = db->db_buf; 1516 1517 ASSERT(db->db_state == DB_NOFILL || arc_released(buf)); 1518 dbuf_clear_data(db); 1519 VERIFY(arc_buf_remove_ref(buf, db)); 1520 dbuf_evict(db); 1521 return (B_TRUE); 1522 } 1523 1524 return (B_FALSE); 1525 } 1526 1527 void 1528 dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx) 1529 { 1530 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1531 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH; 1532 1533 ASSERT(tx->tx_txg != 0); 1534 ASSERT(!refcount_is_zero(&db->db_holds)); 1535 1536 /* 1537 * Quick check for dirtyness. For already dirty blocks, this 1538 * reduces runtime of this function by >90%, and overall performance 1539 * by 50% for some workloads (e.g. file deletion with indirect blocks 1540 * cached). 1541 */ 1542 mutex_enter(&db->db_mtx); 1543 dbuf_dirty_record_t *dr; 1544 for (dr = db->db_last_dirty; 1545 dr != NULL && dr->dr_txg >= tx->tx_txg; dr = dr->dr_next) { 1546 /* 1547 * It's possible that it is already dirty but not cached, 1548 * because there are some calls to dbuf_dirty() that don't 1549 * go through dmu_buf_will_dirty(). 1550 */ 1551 if (dr->dr_txg == tx->tx_txg && db->db_state == DB_CACHED) { 1552 /* This dbuf is already dirty and cached. */ 1553 dbuf_redirty(dr); 1554 mutex_exit(&db->db_mtx); 1555 return; 1556 } 1557 } 1558 mutex_exit(&db->db_mtx); 1559 1560 DB_DNODE_ENTER(db); 1561 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock)) 1562 rf |= DB_RF_HAVESTRUCT; 1563 DB_DNODE_EXIT(db); 1564 (void) dbuf_read(db, NULL, rf); 1565 (void) dbuf_dirty(db, tx); 1566 } 1567 1568 void 1569 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1570 { 1571 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1572 1573 db->db_state = DB_NOFILL; 1574 1575 dmu_buf_will_fill(db_fake, tx); 1576 } 1577 1578 void 1579 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1580 { 1581 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1582 1583 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1584 ASSERT(tx->tx_txg != 0); 1585 ASSERT(db->db_level == 0); 1586 ASSERT(!refcount_is_zero(&db->db_holds)); 1587 1588 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT || 1589 dmu_tx_private_ok(tx)); 1590 1591 dbuf_noread(db); 1592 (void) dbuf_dirty(db, tx); 1593 } 1594 1595 #pragma weak dmu_buf_fill_done = dbuf_fill_done 1596 /* ARGSUSED */ 1597 void 1598 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx) 1599 { 1600 mutex_enter(&db->db_mtx); 1601 DBUF_VERIFY(db); 1602 1603 if (db->db_state == DB_FILL) { 1604 if (db->db_level == 0 && db->db_freed_in_flight) { 1605 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1606 /* we were freed while filling */ 1607 /* XXX dbuf_undirty? */ 1608 bzero(db->db.db_data, db->db.db_size); 1609 db->db_freed_in_flight = FALSE; 1610 } 1611 db->db_state = DB_CACHED; 1612 cv_broadcast(&db->db_changed); 1613 } 1614 mutex_exit(&db->db_mtx); 1615 } 1616 1617 void 1618 dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data, 1619 bp_embedded_type_t etype, enum zio_compress comp, 1620 int uncompressed_size, int compressed_size, int byteorder, 1621 dmu_tx_t *tx) 1622 { 1623 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 1624 struct dirty_leaf *dl; 1625 dmu_object_type_t type; 1626 1627 if (etype == BP_EMBEDDED_TYPE_DATA) { 1628 ASSERT(spa_feature_is_active(dmu_objset_spa(db->db_objset), 1629 SPA_FEATURE_EMBEDDED_DATA)); 1630 } 1631 1632 DB_DNODE_ENTER(db); 1633 type = DB_DNODE(db)->dn_type; 1634 DB_DNODE_EXIT(db); 1635 1636 ASSERT0(db->db_level); 1637 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1638 1639 dmu_buf_will_not_fill(dbuf, tx); 1640 1641 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 1642 dl = &db->db_last_dirty->dt.dl; 1643 encode_embedded_bp_compressed(&dl->dr_overridden_by, 1644 data, comp, uncompressed_size, compressed_size); 1645 BPE_SET_ETYPE(&dl->dr_overridden_by, etype); 1646 BP_SET_TYPE(&dl->dr_overridden_by, type); 1647 BP_SET_LEVEL(&dl->dr_overridden_by, 0); 1648 BP_SET_BYTEORDER(&dl->dr_overridden_by, byteorder); 1649 1650 dl->dr_override_state = DR_OVERRIDDEN; 1651 dl->dr_overridden_by.blk_birth = db->db_last_dirty->dr_txg; 1652 } 1653 1654 /* 1655 * Directly assign a provided arc buf to a given dbuf if it's not referenced 1656 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf. 1657 */ 1658 void 1659 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx) 1660 { 1661 ASSERT(!refcount_is_zero(&db->db_holds)); 1662 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1663 ASSERT(db->db_level == 0); 1664 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA); 1665 ASSERT(buf != NULL); 1666 ASSERT(arc_buf_size(buf) == db->db.db_size); 1667 ASSERT(tx->tx_txg != 0); 1668 1669 arc_return_buf(buf, db); 1670 ASSERT(arc_released(buf)); 1671 1672 mutex_enter(&db->db_mtx); 1673 1674 while (db->db_state == DB_READ || db->db_state == DB_FILL) 1675 cv_wait(&db->db_changed, &db->db_mtx); 1676 1677 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED); 1678 1679 if (db->db_state == DB_CACHED && 1680 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) { 1681 mutex_exit(&db->db_mtx); 1682 (void) dbuf_dirty(db, tx); 1683 bcopy(buf->b_data, db->db.db_data, db->db.db_size); 1684 VERIFY(arc_buf_remove_ref(buf, db)); 1685 xuio_stat_wbuf_copied(); 1686 return; 1687 } 1688 1689 xuio_stat_wbuf_nocopy(); 1690 if (db->db_state == DB_CACHED) { 1691 dbuf_dirty_record_t *dr = db->db_last_dirty; 1692 1693 ASSERT(db->db_buf != NULL); 1694 if (dr != NULL && dr->dr_txg == tx->tx_txg) { 1695 ASSERT(dr->dt.dl.dr_data == db->db_buf); 1696 if (!arc_released(db->db_buf)) { 1697 ASSERT(dr->dt.dl.dr_override_state == 1698 DR_OVERRIDDEN); 1699 arc_release(db->db_buf, db); 1700 } 1701 dr->dt.dl.dr_data = buf; 1702 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1703 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) { 1704 arc_release(db->db_buf, db); 1705 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1706 } 1707 db->db_buf = NULL; 1708 } 1709 ASSERT(db->db_buf == NULL); 1710 dbuf_set_data(db, buf); 1711 db->db_state = DB_FILL; 1712 mutex_exit(&db->db_mtx); 1713 (void) dbuf_dirty(db, tx); 1714 dmu_buf_fill_done(&db->db, tx); 1715 } 1716 1717 /* 1718 * "Clear" the contents of this dbuf. This will mark the dbuf 1719 * EVICTING and clear *most* of its references. Unfortunately, 1720 * when we are not holding the dn_dbufs_mtx, we can't clear the 1721 * entry in the dn_dbufs list. We have to wait until dbuf_destroy() 1722 * in this case. For callers from the DMU we will usually see: 1723 * dbuf_clear()->arc_clear_callback()->dbuf_do_evict()->dbuf_destroy() 1724 * For the arc callback, we will usually see: 1725 * dbuf_do_evict()->dbuf_clear();dbuf_destroy() 1726 * Sometimes, though, we will get a mix of these two: 1727 * DMU: dbuf_clear()->arc_clear_callback() 1728 * ARC: dbuf_do_evict()->dbuf_destroy() 1729 * 1730 * This routine will dissociate the dbuf from the arc, by calling 1731 * arc_clear_callback(), but will not evict the data from the ARC. 1732 */ 1733 void 1734 dbuf_clear(dmu_buf_impl_t *db) 1735 { 1736 dnode_t *dn; 1737 dmu_buf_impl_t *parent = db->db_parent; 1738 dmu_buf_impl_t *dndb; 1739 boolean_t dbuf_gone = B_FALSE; 1740 1741 ASSERT(MUTEX_HELD(&db->db_mtx)); 1742 ASSERT(refcount_is_zero(&db->db_holds)); 1743 1744 dbuf_evict_user(db); 1745 1746 if (db->db_state == DB_CACHED) { 1747 ASSERT(db->db.db_data != NULL); 1748 if (db->db_blkid == DMU_BONUS_BLKID) { 1749 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN); 1750 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 1751 } 1752 db->db.db_data = NULL; 1753 db->db_state = DB_UNCACHED; 1754 } 1755 1756 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL); 1757 ASSERT(db->db_data_pending == NULL); 1758 1759 db->db_state = DB_EVICTING; 1760 db->db_blkptr = NULL; 1761 1762 DB_DNODE_ENTER(db); 1763 dn = DB_DNODE(db); 1764 dndb = dn->dn_dbuf; 1765 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) { 1766 avl_remove(&dn->dn_dbufs, db); 1767 atomic_dec_32(&dn->dn_dbufs_count); 1768 membar_producer(); 1769 DB_DNODE_EXIT(db); 1770 /* 1771 * Decrementing the dbuf count means that the hold corresponding 1772 * to the removed dbuf is no longer discounted in dnode_move(), 1773 * so the dnode cannot be moved until after we release the hold. 1774 * The membar_producer() ensures visibility of the decremented 1775 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually 1776 * release any lock. 1777 */ 1778 dnode_rele(dn, db); 1779 db->db_dnode_handle = NULL; 1780 } else { 1781 DB_DNODE_EXIT(db); 1782 } 1783 1784 if (db->db_buf) 1785 dbuf_gone = arc_clear_callback(db->db_buf); 1786 1787 if (!dbuf_gone) 1788 mutex_exit(&db->db_mtx); 1789 1790 /* 1791 * If this dbuf is referenced from an indirect dbuf, 1792 * decrement the ref count on the indirect dbuf. 1793 */ 1794 if (parent && parent != dndb) 1795 dbuf_rele(parent, db); 1796 } 1797 1798 /* 1799 * Note: While bpp will always be updated if the function returns success, 1800 * parentp will not be updated if the dnode does not have dn_dbuf filled in; 1801 * this happens when the dnode is the meta-dnode, or a userused or groupused 1802 * object. 1803 */ 1804 static int 1805 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, 1806 dmu_buf_impl_t **parentp, blkptr_t **bpp) 1807 { 1808 int nlevels, epbs; 1809 1810 *parentp = NULL; 1811 *bpp = NULL; 1812 1813 ASSERT(blkid != DMU_BONUS_BLKID); 1814 1815 if (blkid == DMU_SPILL_BLKID) { 1816 mutex_enter(&dn->dn_mtx); 1817 if (dn->dn_have_spill && 1818 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) 1819 *bpp = &dn->dn_phys->dn_spill; 1820 else 1821 *bpp = NULL; 1822 dbuf_add_ref(dn->dn_dbuf, NULL); 1823 *parentp = dn->dn_dbuf; 1824 mutex_exit(&dn->dn_mtx); 1825 return (0); 1826 } 1827 1828 if (dn->dn_phys->dn_nlevels == 0) 1829 nlevels = 1; 1830 else 1831 nlevels = dn->dn_phys->dn_nlevels; 1832 1833 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1834 1835 ASSERT3U(level * epbs, <, 64); 1836 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1837 if (level >= nlevels || 1838 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) { 1839 /* the buffer has no parent yet */ 1840 return (SET_ERROR(ENOENT)); 1841 } else if (level < nlevels-1) { 1842 /* this block is referenced from an indirect block */ 1843 int err = dbuf_hold_impl(dn, level+1, 1844 blkid >> epbs, fail_sparse, FALSE, NULL, parentp); 1845 if (err) 1846 return (err); 1847 err = dbuf_read(*parentp, NULL, 1848 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL)); 1849 if (err) { 1850 dbuf_rele(*parentp, NULL); 1851 *parentp = NULL; 1852 return (err); 1853 } 1854 *bpp = ((blkptr_t *)(*parentp)->db.db_data) + 1855 (blkid & ((1ULL << epbs) - 1)); 1856 return (0); 1857 } else { 1858 /* the block is referenced from the dnode */ 1859 ASSERT3U(level, ==, nlevels-1); 1860 ASSERT(dn->dn_phys->dn_nblkptr == 0 || 1861 blkid < dn->dn_phys->dn_nblkptr); 1862 if (dn->dn_dbuf) { 1863 dbuf_add_ref(dn->dn_dbuf, NULL); 1864 *parentp = dn->dn_dbuf; 1865 } 1866 *bpp = &dn->dn_phys->dn_blkptr[blkid]; 1867 return (0); 1868 } 1869 } 1870 1871 static dmu_buf_impl_t * 1872 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid, 1873 dmu_buf_impl_t *parent, blkptr_t *blkptr) 1874 { 1875 objset_t *os = dn->dn_objset; 1876 dmu_buf_impl_t *db, *odb; 1877 1878 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1879 ASSERT(dn->dn_type != DMU_OT_NONE); 1880 1881 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP); 1882 1883 db->db_objset = os; 1884 db->db.db_object = dn->dn_object; 1885 db->db_level = level; 1886 db->db_blkid = blkid; 1887 db->db_last_dirty = NULL; 1888 db->db_dirtycnt = 0; 1889 db->db_dnode_handle = dn->dn_handle; 1890 db->db_parent = parent; 1891 db->db_blkptr = blkptr; 1892 1893 db->db_user = NULL; 1894 db->db_user_immediate_evict = FALSE; 1895 db->db_freed_in_flight = FALSE; 1896 db->db_pending_evict = FALSE; 1897 1898 if (blkid == DMU_BONUS_BLKID) { 1899 ASSERT3P(parent, ==, dn->dn_dbuf); 1900 db->db.db_size = DN_MAX_BONUSLEN - 1901 (dn->dn_nblkptr-1) * sizeof (blkptr_t); 1902 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 1903 db->db.db_offset = DMU_BONUS_BLKID; 1904 db->db_state = DB_UNCACHED; 1905 /* the bonus dbuf is not placed in the hash table */ 1906 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1907 return (db); 1908 } else if (blkid == DMU_SPILL_BLKID) { 1909 db->db.db_size = (blkptr != NULL) ? 1910 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE; 1911 db->db.db_offset = 0; 1912 } else { 1913 int blocksize = 1914 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz; 1915 db->db.db_size = blocksize; 1916 db->db.db_offset = db->db_blkid * blocksize; 1917 } 1918 1919 /* 1920 * Hold the dn_dbufs_mtx while we get the new dbuf 1921 * in the hash table *and* added to the dbufs list. 1922 * This prevents a possible deadlock with someone 1923 * trying to look up this dbuf before its added to the 1924 * dn_dbufs list. 1925 */ 1926 mutex_enter(&dn->dn_dbufs_mtx); 1927 db->db_state = DB_EVICTING; 1928 if ((odb = dbuf_hash_insert(db)) != NULL) { 1929 /* someone else inserted it first */ 1930 kmem_cache_free(dbuf_cache, db); 1931 mutex_exit(&dn->dn_dbufs_mtx); 1932 return (odb); 1933 } 1934 avl_add(&dn->dn_dbufs, db); 1935 if (db->db_level == 0 && db->db_blkid >= 1936 dn->dn_unlisted_l0_blkid) 1937 dn->dn_unlisted_l0_blkid = db->db_blkid + 1; 1938 db->db_state = DB_UNCACHED; 1939 mutex_exit(&dn->dn_dbufs_mtx); 1940 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1941 1942 if (parent && parent != dn->dn_dbuf) 1943 dbuf_add_ref(parent, db); 1944 1945 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1946 refcount_count(&dn->dn_holds) > 0); 1947 (void) refcount_add(&dn->dn_holds, db); 1948 atomic_inc_32(&dn->dn_dbufs_count); 1949 1950 dprintf_dbuf(db, "db=%p\n", db); 1951 1952 return (db); 1953 } 1954 1955 static int 1956 dbuf_do_evict(void *private) 1957 { 1958 dmu_buf_impl_t *db = private; 1959 1960 if (!MUTEX_HELD(&db->db_mtx)) 1961 mutex_enter(&db->db_mtx); 1962 1963 ASSERT(refcount_is_zero(&db->db_holds)); 1964 1965 if (db->db_state != DB_EVICTING) { 1966 ASSERT(db->db_state == DB_CACHED); 1967 DBUF_VERIFY(db); 1968 db->db_buf = NULL; 1969 dbuf_evict(db); 1970 } else { 1971 mutex_exit(&db->db_mtx); 1972 dbuf_destroy(db); 1973 } 1974 return (0); 1975 } 1976 1977 static void 1978 dbuf_destroy(dmu_buf_impl_t *db) 1979 { 1980 ASSERT(refcount_is_zero(&db->db_holds)); 1981 1982 if (db->db_blkid != DMU_BONUS_BLKID) { 1983 /* 1984 * If this dbuf is still on the dn_dbufs list, 1985 * remove it from that list. 1986 */ 1987 if (db->db_dnode_handle != NULL) { 1988 dnode_t *dn; 1989 1990 DB_DNODE_ENTER(db); 1991 dn = DB_DNODE(db); 1992 mutex_enter(&dn->dn_dbufs_mtx); 1993 avl_remove(&dn->dn_dbufs, db); 1994 atomic_dec_32(&dn->dn_dbufs_count); 1995 mutex_exit(&dn->dn_dbufs_mtx); 1996 DB_DNODE_EXIT(db); 1997 /* 1998 * Decrementing the dbuf count means that the hold 1999 * corresponding to the removed dbuf is no longer 2000 * discounted in dnode_move(), so the dnode cannot be 2001 * moved until after we release the hold. 2002 */ 2003 dnode_rele(dn, db); 2004 db->db_dnode_handle = NULL; 2005 } 2006 dbuf_hash_remove(db); 2007 } 2008 db->db_parent = NULL; 2009 db->db_buf = NULL; 2010 2011 ASSERT(db->db.db_data == NULL); 2012 ASSERT(db->db_hash_next == NULL); 2013 ASSERT(db->db_blkptr == NULL); 2014 ASSERT(db->db_data_pending == NULL); 2015 2016 kmem_cache_free(dbuf_cache, db); 2017 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 2018 } 2019 2020 typedef struct dbuf_prefetch_arg { 2021 spa_t *dpa_spa; /* The spa to issue the prefetch in. */ 2022 zbookmark_phys_t dpa_zb; /* The target block to prefetch. */ 2023 int dpa_epbs; /* Entries (blkptr_t's) Per Block Shift. */ 2024 int dpa_curlevel; /* The current level that we're reading */ 2025 zio_priority_t dpa_prio; /* The priority I/Os should be issued at. */ 2026 zio_t *dpa_zio; /* The parent zio_t for all prefetches. */ 2027 arc_flags_t dpa_aflags; /* Flags to pass to the final prefetch. */ 2028 } dbuf_prefetch_arg_t; 2029 2030 /* 2031 * Actually issue the prefetch read for the block given. 2032 */ 2033 static void 2034 dbuf_issue_final_prefetch(dbuf_prefetch_arg_t *dpa, blkptr_t *bp) 2035 { 2036 if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) 2037 return; 2038 2039 arc_flags_t aflags = 2040 dpa->dpa_aflags | ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH; 2041 2042 ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); 2043 ASSERT3U(dpa->dpa_curlevel, ==, dpa->dpa_zb.zb_level); 2044 ASSERT(dpa->dpa_zio != NULL); 2045 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, bp, NULL, NULL, 2046 dpa->dpa_prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2047 &aflags, &dpa->dpa_zb); 2048 } 2049 2050 /* 2051 * Called when an indirect block above our prefetch target is read in. This 2052 * will either read in the next indirect block down the tree or issue the actual 2053 * prefetch if the next block down is our target. 2054 */ 2055 static void 2056 dbuf_prefetch_indirect_done(zio_t *zio, arc_buf_t *abuf, void *private) 2057 { 2058 dbuf_prefetch_arg_t *dpa = private; 2059 2060 ASSERT3S(dpa->dpa_zb.zb_level, <, dpa->dpa_curlevel); 2061 ASSERT3S(dpa->dpa_curlevel, >, 0); 2062 if (zio != NULL) { 2063 ASSERT3S(BP_GET_LEVEL(zio->io_bp), ==, dpa->dpa_curlevel); 2064 ASSERT3U(BP_GET_LSIZE(zio->io_bp), ==, zio->io_size); 2065 ASSERT3P(zio->io_spa, ==, dpa->dpa_spa); 2066 } 2067 2068 dpa->dpa_curlevel--; 2069 2070 uint64_t nextblkid = dpa->dpa_zb.zb_blkid >> 2071 (dpa->dpa_epbs * (dpa->dpa_curlevel - dpa->dpa_zb.zb_level)); 2072 blkptr_t *bp = ((blkptr_t *)abuf->b_data) + 2073 P2PHASE(nextblkid, 1ULL << dpa->dpa_epbs); 2074 if (BP_IS_HOLE(bp) || (zio != NULL && zio->io_error != 0)) { 2075 kmem_free(dpa, sizeof (*dpa)); 2076 } else if (dpa->dpa_curlevel == dpa->dpa_zb.zb_level) { 2077 ASSERT3U(nextblkid, ==, dpa->dpa_zb.zb_blkid); 2078 dbuf_issue_final_prefetch(dpa, bp); 2079 kmem_free(dpa, sizeof (*dpa)); 2080 } else { 2081 arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; 2082 zbookmark_phys_t zb; 2083 2084 ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); 2085 2086 SET_BOOKMARK(&zb, dpa->dpa_zb.zb_objset, 2087 dpa->dpa_zb.zb_object, dpa->dpa_curlevel, nextblkid); 2088 2089 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, 2090 bp, dbuf_prefetch_indirect_done, dpa, dpa->dpa_prio, 2091 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2092 &iter_aflags, &zb); 2093 } 2094 (void) arc_buf_remove_ref(abuf, private); 2095 } 2096 2097 /* 2098 * Issue prefetch reads for the given block on the given level. If the indirect 2099 * blocks above that block are not in memory, we will read them in 2100 * asynchronously. As a result, this call never blocks waiting for a read to 2101 * complete. 2102 */ 2103 void 2104 dbuf_prefetch(dnode_t *dn, int64_t level, uint64_t blkid, zio_priority_t prio, 2105 arc_flags_t aflags) 2106 { 2107 blkptr_t bp; 2108 int epbs, nlevels, curlevel; 2109 uint64_t curblkid; 2110 2111 ASSERT(blkid != DMU_BONUS_BLKID); 2112 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 2113 2114 if (blkid > dn->dn_maxblkid) 2115 return; 2116 2117 if (dnode_block_freed(dn, blkid)) 2118 return; 2119 2120 /* 2121 * This dnode hasn't been written to disk yet, so there's nothing to 2122 * prefetch. 2123 */ 2124 nlevels = dn->dn_phys->dn_nlevels; 2125 if (level >= nlevels || dn->dn_phys->dn_nblkptr == 0) 2126 return; 2127 2128 epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2129 if (dn->dn_phys->dn_maxblkid < blkid << (epbs * level)) 2130 return; 2131 2132 dmu_buf_impl_t *db = dbuf_find(dn->dn_objset, dn->dn_object, 2133 level, blkid); 2134 if (db != NULL) { 2135 mutex_exit(&db->db_mtx); 2136 /* 2137 * This dbuf already exists. It is either CACHED, or 2138 * (we assume) about to be read or filled. 2139 */ 2140 return; 2141 } 2142 2143 /* 2144 * Find the closest ancestor (indirect block) of the target block 2145 * that is present in the cache. In this indirect block, we will 2146 * find the bp that is at curlevel, curblkid. 2147 */ 2148 curlevel = level; 2149 curblkid = blkid; 2150 while (curlevel < nlevels - 1) { 2151 int parent_level = curlevel + 1; 2152 uint64_t parent_blkid = curblkid >> epbs; 2153 dmu_buf_impl_t *db; 2154 2155 if (dbuf_hold_impl(dn, parent_level, parent_blkid, 2156 FALSE, TRUE, FTAG, &db) == 0) { 2157 blkptr_t *bpp = db->db_buf->b_data; 2158 bp = bpp[P2PHASE(curblkid, 1 << epbs)]; 2159 dbuf_rele(db, FTAG); 2160 break; 2161 } 2162 2163 curlevel = parent_level; 2164 curblkid = parent_blkid; 2165 } 2166 2167 if (curlevel == nlevels - 1) { 2168 /* No cached indirect blocks found. */ 2169 ASSERT3U(curblkid, <, dn->dn_phys->dn_nblkptr); 2170 bp = dn->dn_phys->dn_blkptr[curblkid]; 2171 } 2172 if (BP_IS_HOLE(&bp)) 2173 return; 2174 2175 ASSERT3U(curlevel, ==, BP_GET_LEVEL(&bp)); 2176 2177 zio_t *pio = zio_root(dmu_objset_spa(dn->dn_objset), NULL, NULL, 2178 ZIO_FLAG_CANFAIL); 2179 2180 dbuf_prefetch_arg_t *dpa = kmem_zalloc(sizeof (*dpa), KM_SLEEP); 2181 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; 2182 SET_BOOKMARK(&dpa->dpa_zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, 2183 dn->dn_object, level, blkid); 2184 dpa->dpa_curlevel = curlevel; 2185 dpa->dpa_prio = prio; 2186 dpa->dpa_aflags = aflags; 2187 dpa->dpa_spa = dn->dn_objset->os_spa; 2188 dpa->dpa_epbs = epbs; 2189 dpa->dpa_zio = pio; 2190 2191 /* 2192 * If we have the indirect just above us, no need to do the asynchronous 2193 * prefetch chain; we'll just run the last step ourselves. If we're at 2194 * a higher level, though, we want to issue the prefetches for all the 2195 * indirect blocks asynchronously, so we can go on with whatever we were 2196 * doing. 2197 */ 2198 if (curlevel == level) { 2199 ASSERT3U(curblkid, ==, blkid); 2200 dbuf_issue_final_prefetch(dpa, &bp); 2201 kmem_free(dpa, sizeof (*dpa)); 2202 } else { 2203 arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; 2204 zbookmark_phys_t zb; 2205 2206 SET_BOOKMARK(&zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, 2207 dn->dn_object, curlevel, curblkid); 2208 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, 2209 &bp, dbuf_prefetch_indirect_done, dpa, prio, 2210 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2211 &iter_aflags, &zb); 2212 } 2213 /* 2214 * We use pio here instead of dpa_zio since it's possible that 2215 * dpa may have already been freed. 2216 */ 2217 zio_nowait(pio); 2218 } 2219 2220 /* 2221 * Returns with db_holds incremented, and db_mtx not held. 2222 * Note: dn_struct_rwlock must be held. 2223 */ 2224 int 2225 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, 2226 boolean_t fail_sparse, boolean_t fail_uncached, 2227 void *tag, dmu_buf_impl_t **dbp) 2228 { 2229 dmu_buf_impl_t *db, *parent = NULL; 2230 2231 ASSERT(blkid != DMU_BONUS_BLKID); 2232 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 2233 ASSERT3U(dn->dn_nlevels, >, level); 2234 2235 *dbp = NULL; 2236 top: 2237 /* dbuf_find() returns with db_mtx held */ 2238 db = dbuf_find(dn->dn_objset, dn->dn_object, level, blkid); 2239 2240 if (db == NULL) { 2241 blkptr_t *bp = NULL; 2242 int err; 2243 2244 if (fail_uncached) 2245 return (SET_ERROR(ENOENT)); 2246 2247 ASSERT3P(parent, ==, NULL); 2248 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp); 2249 if (fail_sparse) { 2250 if (err == 0 && bp && BP_IS_HOLE(bp)) 2251 err = SET_ERROR(ENOENT); 2252 if (err) { 2253 if (parent) 2254 dbuf_rele(parent, NULL); 2255 return (err); 2256 } 2257 } 2258 if (err && err != ENOENT) 2259 return (err); 2260 db = dbuf_create(dn, level, blkid, parent, bp); 2261 } 2262 2263 if (fail_uncached && db->db_state != DB_CACHED) { 2264 mutex_exit(&db->db_mtx); 2265 return (SET_ERROR(ENOENT)); 2266 } 2267 2268 if (db->db_buf && refcount_is_zero(&db->db_holds)) { 2269 arc_buf_add_ref(db->db_buf, db); 2270 if (db->db_buf->b_data == NULL) { 2271 dbuf_clear(db); 2272 if (parent) { 2273 dbuf_rele(parent, NULL); 2274 parent = NULL; 2275 } 2276 goto top; 2277 } 2278 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data); 2279 } 2280 2281 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf)); 2282 2283 /* 2284 * If this buffer is currently syncing out, and we are are 2285 * still referencing it from db_data, we need to make a copy 2286 * of it in case we decide we want to dirty it again in this txg. 2287 */ 2288 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 2289 dn->dn_object != DMU_META_DNODE_OBJECT && 2290 db->db_state == DB_CACHED && db->db_data_pending) { 2291 dbuf_dirty_record_t *dr = db->db_data_pending; 2292 2293 if (dr->dt.dl.dr_data == db->db_buf) { 2294 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2295 2296 dbuf_set_data(db, 2297 arc_buf_alloc(dn->dn_objset->os_spa, 2298 db->db.db_size, db, type)); 2299 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data, 2300 db->db.db_size); 2301 } 2302 } 2303 2304 (void) refcount_add(&db->db_holds, tag); 2305 DBUF_VERIFY(db); 2306 mutex_exit(&db->db_mtx); 2307 2308 /* NOTE: we can't rele the parent until after we drop the db_mtx */ 2309 if (parent) 2310 dbuf_rele(parent, NULL); 2311 2312 ASSERT3P(DB_DNODE(db), ==, dn); 2313 ASSERT3U(db->db_blkid, ==, blkid); 2314 ASSERT3U(db->db_level, ==, level); 2315 *dbp = db; 2316 2317 return (0); 2318 } 2319 2320 dmu_buf_impl_t * 2321 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag) 2322 { 2323 return (dbuf_hold_level(dn, 0, blkid, tag)); 2324 } 2325 2326 dmu_buf_impl_t * 2327 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag) 2328 { 2329 dmu_buf_impl_t *db; 2330 int err = dbuf_hold_impl(dn, level, blkid, FALSE, FALSE, tag, &db); 2331 return (err ? NULL : db); 2332 } 2333 2334 void 2335 dbuf_create_bonus(dnode_t *dn) 2336 { 2337 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 2338 2339 ASSERT(dn->dn_bonus == NULL); 2340 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL); 2341 } 2342 2343 int 2344 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx) 2345 { 2346 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2347 dnode_t *dn; 2348 2349 if (db->db_blkid != DMU_SPILL_BLKID) 2350 return (SET_ERROR(ENOTSUP)); 2351 if (blksz == 0) 2352 blksz = SPA_MINBLOCKSIZE; 2353 ASSERT3U(blksz, <=, spa_maxblocksize(dmu_objset_spa(db->db_objset))); 2354 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE); 2355 2356 DB_DNODE_ENTER(db); 2357 dn = DB_DNODE(db); 2358 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 2359 dbuf_new_size(db, blksz, tx); 2360 rw_exit(&dn->dn_struct_rwlock); 2361 DB_DNODE_EXIT(db); 2362 2363 return (0); 2364 } 2365 2366 void 2367 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx) 2368 { 2369 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx); 2370 } 2371 2372 #pragma weak dmu_buf_add_ref = dbuf_add_ref 2373 void 2374 dbuf_add_ref(dmu_buf_impl_t *db, void *tag) 2375 { 2376 int64_t holds = refcount_add(&db->db_holds, tag); 2377 ASSERT(holds > 1); 2378 } 2379 2380 #pragma weak dmu_buf_try_add_ref = dbuf_try_add_ref 2381 boolean_t 2382 dbuf_try_add_ref(dmu_buf_t *db_fake, objset_t *os, uint64_t obj, uint64_t blkid, 2383 void *tag) 2384 { 2385 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2386 dmu_buf_impl_t *found_db; 2387 boolean_t result = B_FALSE; 2388 2389 if (db->db_blkid == DMU_BONUS_BLKID) 2390 found_db = dbuf_find_bonus(os, obj); 2391 else 2392 found_db = dbuf_find(os, obj, 0, blkid); 2393 2394 if (found_db != NULL) { 2395 if (db == found_db && dbuf_refcount(db) > db->db_dirtycnt) { 2396 (void) refcount_add(&db->db_holds, tag); 2397 result = B_TRUE; 2398 } 2399 mutex_exit(&db->db_mtx); 2400 } 2401 return (result); 2402 } 2403 2404 /* 2405 * If you call dbuf_rele() you had better not be referencing the dnode handle 2406 * unless you have some other direct or indirect hold on the dnode. (An indirect 2407 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.) 2408 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the 2409 * dnode's parent dbuf evicting its dnode handles. 2410 */ 2411 void 2412 dbuf_rele(dmu_buf_impl_t *db, void *tag) 2413 { 2414 mutex_enter(&db->db_mtx); 2415 dbuf_rele_and_unlock(db, tag); 2416 } 2417 2418 void 2419 dmu_buf_rele(dmu_buf_t *db, void *tag) 2420 { 2421 dbuf_rele((dmu_buf_impl_t *)db, tag); 2422 } 2423 2424 /* 2425 * dbuf_rele() for an already-locked dbuf. This is necessary to allow 2426 * db_dirtycnt and db_holds to be updated atomically. 2427 */ 2428 void 2429 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) 2430 { 2431 int64_t holds; 2432 2433 ASSERT(MUTEX_HELD(&db->db_mtx)); 2434 DBUF_VERIFY(db); 2435 2436 /* 2437 * Remove the reference to the dbuf before removing its hold on the 2438 * dnode so we can guarantee in dnode_move() that a referenced bonus 2439 * buffer has a corresponding dnode hold. 2440 */ 2441 holds = refcount_remove(&db->db_holds, tag); 2442 ASSERT(holds >= 0); 2443 2444 /* 2445 * We can't freeze indirects if there is a possibility that they 2446 * may be modified in the current syncing context. 2447 */ 2448 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0)) 2449 arc_buf_freeze(db->db_buf); 2450 2451 if (holds == db->db_dirtycnt && 2452 db->db_level == 0 && db->db_user_immediate_evict) 2453 dbuf_evict_user(db); 2454 2455 if (holds == 0) { 2456 if (db->db_blkid == DMU_BONUS_BLKID) { 2457 dnode_t *dn; 2458 boolean_t evict_dbuf = db->db_pending_evict; 2459 2460 /* 2461 * If the dnode moves here, we cannot cross this 2462 * barrier until the move completes. 2463 */ 2464 DB_DNODE_ENTER(db); 2465 2466 dn = DB_DNODE(db); 2467 atomic_dec_32(&dn->dn_dbufs_count); 2468 2469 /* 2470 * Decrementing the dbuf count means that the bonus 2471 * buffer's dnode hold is no longer discounted in 2472 * dnode_move(). The dnode cannot move until after 2473 * the dnode_rele() below. 2474 */ 2475 DB_DNODE_EXIT(db); 2476 2477 /* 2478 * Do not reference db after its lock is dropped. 2479 * Another thread may evict it. 2480 */ 2481 mutex_exit(&db->db_mtx); 2482 2483 if (evict_dbuf) 2484 dnode_evict_bonus(dn); 2485 2486 dnode_rele(dn, db); 2487 } else if (db->db_buf == NULL) { 2488 /* 2489 * This is a special case: we never associated this 2490 * dbuf with any data allocated from the ARC. 2491 */ 2492 ASSERT(db->db_state == DB_UNCACHED || 2493 db->db_state == DB_NOFILL); 2494 dbuf_evict(db); 2495 } else if (arc_released(db->db_buf)) { 2496 arc_buf_t *buf = db->db_buf; 2497 /* 2498 * This dbuf has anonymous data associated with it. 2499 */ 2500 dbuf_clear_data(db); 2501 VERIFY(arc_buf_remove_ref(buf, db)); 2502 dbuf_evict(db); 2503 } else { 2504 VERIFY(!arc_buf_remove_ref(db->db_buf, db)); 2505 2506 /* 2507 * A dbuf will be eligible for eviction if either the 2508 * 'primarycache' property is set or a duplicate 2509 * copy of this buffer is already cached in the arc. 2510 * 2511 * In the case of the 'primarycache' a buffer 2512 * is considered for eviction if it matches the 2513 * criteria set in the property. 2514 * 2515 * To decide if our buffer is considered a 2516 * duplicate, we must call into the arc to determine 2517 * if multiple buffers are referencing the same 2518 * block on-disk. If so, then we simply evict 2519 * ourselves. 2520 */ 2521 if (!DBUF_IS_CACHEABLE(db)) { 2522 if (db->db_blkptr != NULL && 2523 !BP_IS_HOLE(db->db_blkptr) && 2524 !BP_IS_EMBEDDED(db->db_blkptr)) { 2525 spa_t *spa = 2526 dmu_objset_spa(db->db_objset); 2527 blkptr_t bp = *db->db_blkptr; 2528 dbuf_clear(db); 2529 arc_freed(spa, &bp); 2530 } else { 2531 dbuf_clear(db); 2532 } 2533 } else if (db->db_pending_evict || 2534 arc_buf_eviction_needed(db->db_buf)) { 2535 dbuf_clear(db); 2536 } else { 2537 mutex_exit(&db->db_mtx); 2538 } 2539 } 2540 } else { 2541 mutex_exit(&db->db_mtx); 2542 } 2543 } 2544 2545 #pragma weak dmu_buf_refcount = dbuf_refcount 2546 uint64_t 2547 dbuf_refcount(dmu_buf_impl_t *db) 2548 { 2549 return (refcount_count(&db->db_holds)); 2550 } 2551 2552 void * 2553 dmu_buf_replace_user(dmu_buf_t *db_fake, dmu_buf_user_t *old_user, 2554 dmu_buf_user_t *new_user) 2555 { 2556 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2557 2558 mutex_enter(&db->db_mtx); 2559 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2560 if (db->db_user == old_user) 2561 db->db_user = new_user; 2562 else 2563 old_user = db->db_user; 2564 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2565 mutex_exit(&db->db_mtx); 2566 2567 return (old_user); 2568 } 2569 2570 void * 2571 dmu_buf_set_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2572 { 2573 return (dmu_buf_replace_user(db_fake, NULL, user)); 2574 } 2575 2576 void * 2577 dmu_buf_set_user_ie(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2578 { 2579 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2580 2581 db->db_user_immediate_evict = TRUE; 2582 return (dmu_buf_set_user(db_fake, user)); 2583 } 2584 2585 void * 2586 dmu_buf_remove_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2587 { 2588 return (dmu_buf_replace_user(db_fake, user, NULL)); 2589 } 2590 2591 void * 2592 dmu_buf_get_user(dmu_buf_t *db_fake) 2593 { 2594 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2595 2596 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2597 return (db->db_user); 2598 } 2599 2600 void 2601 dmu_buf_user_evict_wait() 2602 { 2603 taskq_wait(dbu_evict_taskq); 2604 } 2605 2606 boolean_t 2607 dmu_buf_freeable(dmu_buf_t *dbuf) 2608 { 2609 boolean_t res = B_FALSE; 2610 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 2611 2612 if (db->db_blkptr) 2613 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset, 2614 db->db_blkptr, db->db_blkptr->blk_birth); 2615 2616 return (res); 2617 } 2618 2619 blkptr_t * 2620 dmu_buf_get_blkptr(dmu_buf_t *db) 2621 { 2622 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; 2623 return (dbi->db_blkptr); 2624 } 2625 2626 static void 2627 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db) 2628 { 2629 /* ASSERT(dmu_tx_is_syncing(tx) */ 2630 ASSERT(MUTEX_HELD(&db->db_mtx)); 2631 2632 if (db->db_blkptr != NULL) 2633 return; 2634 2635 if (db->db_blkid == DMU_SPILL_BLKID) { 2636 db->db_blkptr = &dn->dn_phys->dn_spill; 2637 BP_ZERO(db->db_blkptr); 2638 return; 2639 } 2640 if (db->db_level == dn->dn_phys->dn_nlevels-1) { 2641 /* 2642 * This buffer was allocated at a time when there was 2643 * no available blkptrs from the dnode, or it was 2644 * inappropriate to hook it in (i.e., nlevels mis-match). 2645 */ 2646 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr); 2647 ASSERT(db->db_parent == NULL); 2648 db->db_parent = dn->dn_dbuf; 2649 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid]; 2650 DBUF_VERIFY(db); 2651 } else { 2652 dmu_buf_impl_t *parent = db->db_parent; 2653 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2654 2655 ASSERT(dn->dn_phys->dn_nlevels > 1); 2656 if (parent == NULL) { 2657 mutex_exit(&db->db_mtx); 2658 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2659 parent = dbuf_hold_level(dn, db->db_level + 1, 2660 db->db_blkid >> epbs, db); 2661 rw_exit(&dn->dn_struct_rwlock); 2662 mutex_enter(&db->db_mtx); 2663 db->db_parent = parent; 2664 } 2665 db->db_blkptr = (blkptr_t *)parent->db.db_data + 2666 (db->db_blkid & ((1ULL << epbs) - 1)); 2667 DBUF_VERIFY(db); 2668 } 2669 } 2670 2671 static void 2672 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2673 { 2674 dmu_buf_impl_t *db = dr->dr_dbuf; 2675 dnode_t *dn; 2676 zio_t *zio; 2677 2678 ASSERT(dmu_tx_is_syncing(tx)); 2679 2680 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2681 2682 mutex_enter(&db->db_mtx); 2683 2684 ASSERT(db->db_level > 0); 2685 DBUF_VERIFY(db); 2686 2687 /* Read the block if it hasn't been read yet. */ 2688 if (db->db_buf == NULL) { 2689 mutex_exit(&db->db_mtx); 2690 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); 2691 mutex_enter(&db->db_mtx); 2692 } 2693 ASSERT3U(db->db_state, ==, DB_CACHED); 2694 ASSERT(db->db_buf != NULL); 2695 2696 DB_DNODE_ENTER(db); 2697 dn = DB_DNODE(db); 2698 /* Indirect block size must match what the dnode thinks it is. */ 2699 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2700 dbuf_check_blkptr(dn, db); 2701 DB_DNODE_EXIT(db); 2702 2703 /* Provide the pending dirty record to child dbufs */ 2704 db->db_data_pending = dr; 2705 2706 mutex_exit(&db->db_mtx); 2707 dbuf_write(dr, db->db_buf, tx); 2708 2709 zio = dr->dr_zio; 2710 mutex_enter(&dr->dt.di.dr_mtx); 2711 dbuf_sync_list(&dr->dt.di.dr_children, db->db_level - 1, tx); 2712 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2713 mutex_exit(&dr->dt.di.dr_mtx); 2714 zio_nowait(zio); 2715 } 2716 2717 static void 2718 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2719 { 2720 arc_buf_t **datap = &dr->dt.dl.dr_data; 2721 dmu_buf_impl_t *db = dr->dr_dbuf; 2722 dnode_t *dn; 2723 objset_t *os; 2724 uint64_t txg = tx->tx_txg; 2725 2726 ASSERT(dmu_tx_is_syncing(tx)); 2727 2728 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2729 2730 mutex_enter(&db->db_mtx); 2731 /* 2732 * To be synced, we must be dirtied. But we 2733 * might have been freed after the dirty. 2734 */ 2735 if (db->db_state == DB_UNCACHED) { 2736 /* This buffer has been freed since it was dirtied */ 2737 ASSERT(db->db.db_data == NULL); 2738 } else if (db->db_state == DB_FILL) { 2739 /* This buffer was freed and is now being re-filled */ 2740 ASSERT(db->db.db_data != dr->dt.dl.dr_data); 2741 } else { 2742 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); 2743 } 2744 DBUF_VERIFY(db); 2745 2746 DB_DNODE_ENTER(db); 2747 dn = DB_DNODE(db); 2748 2749 if (db->db_blkid == DMU_SPILL_BLKID) { 2750 mutex_enter(&dn->dn_mtx); 2751 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR; 2752 mutex_exit(&dn->dn_mtx); 2753 } 2754 2755 /* 2756 * If this is a bonus buffer, simply copy the bonus data into the 2757 * dnode. It will be written out when the dnode is synced (and it 2758 * will be synced, since it must have been dirty for dbuf_sync to 2759 * be called). 2760 */ 2761 if (db->db_blkid == DMU_BONUS_BLKID) { 2762 dbuf_dirty_record_t **drp; 2763 2764 ASSERT(*datap != NULL); 2765 ASSERT0(db->db_level); 2766 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN); 2767 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen); 2768 DB_DNODE_EXIT(db); 2769 2770 if (*datap != db->db.db_data) { 2771 zio_buf_free(*datap, DN_MAX_BONUSLEN); 2772 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 2773 } 2774 db->db_data_pending = NULL; 2775 drp = &db->db_last_dirty; 2776 while (*drp != dr) 2777 drp = &(*drp)->dr_next; 2778 ASSERT(dr->dr_next == NULL); 2779 ASSERT(dr->dr_dbuf == db); 2780 *drp = dr->dr_next; 2781 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2782 ASSERT(db->db_dirtycnt > 0); 2783 db->db_dirtycnt -= 1; 2784 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2785 return; 2786 } 2787 2788 os = dn->dn_objset; 2789 2790 /* 2791 * This function may have dropped the db_mtx lock allowing a dmu_sync 2792 * operation to sneak in. As a result, we need to ensure that we 2793 * don't check the dr_override_state until we have returned from 2794 * dbuf_check_blkptr. 2795 */ 2796 dbuf_check_blkptr(dn, db); 2797 2798 /* 2799 * If this buffer is in the middle of an immediate write, 2800 * wait for the synchronous IO to complete. 2801 */ 2802 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) { 2803 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); 2804 cv_wait(&db->db_changed, &db->db_mtx); 2805 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN); 2806 } 2807 2808 if (db->db_state != DB_NOFILL && 2809 dn->dn_object != DMU_META_DNODE_OBJECT && 2810 refcount_count(&db->db_holds) > 1 && 2811 dr->dt.dl.dr_override_state != DR_OVERRIDDEN && 2812 *datap == db->db_buf) { 2813 /* 2814 * If this buffer is currently "in use" (i.e., there 2815 * are active holds and db_data still references it), 2816 * then make a copy before we start the write so that 2817 * any modifications from the open txg will not leak 2818 * into this write. 2819 * 2820 * NOTE: this copy does not need to be made for 2821 * objects only modified in the syncing context (e.g. 2822 * DNONE_DNODE blocks). 2823 */ 2824 int blksz = arc_buf_size(*datap); 2825 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2826 *datap = arc_buf_alloc(os->os_spa, blksz, db, type); 2827 bcopy(db->db.db_data, (*datap)->b_data, blksz); 2828 } 2829 db->db_data_pending = dr; 2830 2831 mutex_exit(&db->db_mtx); 2832 2833 dbuf_write(dr, *datap, tx); 2834 2835 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2836 if (dn->dn_object == DMU_META_DNODE_OBJECT) { 2837 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr); 2838 DB_DNODE_EXIT(db); 2839 } else { 2840 /* 2841 * Although zio_nowait() does not "wait for an IO", it does 2842 * initiate the IO. If this is an empty write it seems plausible 2843 * that the IO could actually be completed before the nowait 2844 * returns. We need to DB_DNODE_EXIT() first in case 2845 * zio_nowait() invalidates the dbuf. 2846 */ 2847 DB_DNODE_EXIT(db); 2848 zio_nowait(dr->dr_zio); 2849 } 2850 } 2851 2852 void 2853 dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx) 2854 { 2855 dbuf_dirty_record_t *dr; 2856 2857 while (dr = list_head(list)) { 2858 if (dr->dr_zio != NULL) { 2859 /* 2860 * If we find an already initialized zio then we 2861 * are processing the meta-dnode, and we have finished. 2862 * The dbufs for all dnodes are put back on the list 2863 * during processing, so that we can zio_wait() 2864 * these IOs after initiating all child IOs. 2865 */ 2866 ASSERT3U(dr->dr_dbuf->db.db_object, ==, 2867 DMU_META_DNODE_OBJECT); 2868 break; 2869 } 2870 if (dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID && 2871 dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) { 2872 VERIFY3U(dr->dr_dbuf->db_level, ==, level); 2873 } 2874 list_remove(list, dr); 2875 if (dr->dr_dbuf->db_level > 0) 2876 dbuf_sync_indirect(dr, tx); 2877 else 2878 dbuf_sync_leaf(dr, tx); 2879 } 2880 } 2881 2882 /* ARGSUSED */ 2883 static void 2884 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb) 2885 { 2886 dmu_buf_impl_t *db = vdb; 2887 dnode_t *dn; 2888 blkptr_t *bp = zio->io_bp; 2889 blkptr_t *bp_orig = &zio->io_bp_orig; 2890 spa_t *spa = zio->io_spa; 2891 int64_t delta; 2892 uint64_t fill = 0; 2893 int i; 2894 2895 ASSERT3P(db->db_blkptr, ==, bp); 2896 2897 DB_DNODE_ENTER(db); 2898 dn = DB_DNODE(db); 2899 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig); 2900 dnode_diduse_space(dn, delta - zio->io_prev_space_delta); 2901 zio->io_prev_space_delta = delta; 2902 2903 if (bp->blk_birth != 0) { 2904 ASSERT((db->db_blkid != DMU_SPILL_BLKID && 2905 BP_GET_TYPE(bp) == dn->dn_type) || 2906 (db->db_blkid == DMU_SPILL_BLKID && 2907 BP_GET_TYPE(bp) == dn->dn_bonustype) || 2908 BP_IS_EMBEDDED(bp)); 2909 ASSERT(BP_GET_LEVEL(bp) == db->db_level); 2910 } 2911 2912 mutex_enter(&db->db_mtx); 2913 2914 #ifdef ZFS_DEBUG 2915 if (db->db_blkid == DMU_SPILL_BLKID) { 2916 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2917 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2918 db->db_blkptr == &dn->dn_phys->dn_spill); 2919 } 2920 #endif 2921 2922 if (db->db_level == 0) { 2923 mutex_enter(&dn->dn_mtx); 2924 if (db->db_blkid > dn->dn_phys->dn_maxblkid && 2925 db->db_blkid != DMU_SPILL_BLKID) 2926 dn->dn_phys->dn_maxblkid = db->db_blkid; 2927 mutex_exit(&dn->dn_mtx); 2928 2929 if (dn->dn_type == DMU_OT_DNODE) { 2930 dnode_phys_t *dnp = db->db.db_data; 2931 for (i = db->db.db_size >> DNODE_SHIFT; i > 0; 2932 i--, dnp++) { 2933 if (dnp->dn_type != DMU_OT_NONE) 2934 fill++; 2935 } 2936 } else { 2937 if (BP_IS_HOLE(bp)) { 2938 fill = 0; 2939 } else { 2940 fill = 1; 2941 } 2942 } 2943 } else { 2944 blkptr_t *ibp = db->db.db_data; 2945 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2946 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) { 2947 if (BP_IS_HOLE(ibp)) 2948 continue; 2949 fill += BP_GET_FILL(ibp); 2950 } 2951 } 2952 DB_DNODE_EXIT(db); 2953 2954 if (!BP_IS_EMBEDDED(bp)) 2955 bp->blk_fill = fill; 2956 2957 mutex_exit(&db->db_mtx); 2958 } 2959 2960 /* 2961 * The SPA will call this callback several times for each zio - once 2962 * for every physical child i/o (zio->io_phys_children times). This 2963 * allows the DMU to monitor the progress of each logical i/o. For example, 2964 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z 2965 * block. There may be a long delay before all copies/fragments are completed, 2966 * so this callback allows us to retire dirty space gradually, as the physical 2967 * i/os complete. 2968 */ 2969 /* ARGSUSED */ 2970 static void 2971 dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg) 2972 { 2973 dmu_buf_impl_t *db = arg; 2974 objset_t *os = db->db_objset; 2975 dsl_pool_t *dp = dmu_objset_pool(os); 2976 dbuf_dirty_record_t *dr; 2977 int delta = 0; 2978 2979 dr = db->db_data_pending; 2980 ASSERT3U(dr->dr_txg, ==, zio->io_txg); 2981 2982 /* 2983 * The callback will be called io_phys_children times. Retire one 2984 * portion of our dirty space each time we are called. Any rounding 2985 * error will be cleaned up by dsl_pool_sync()'s call to 2986 * dsl_pool_undirty_space(). 2987 */ 2988 delta = dr->dr_accounted / zio->io_phys_children; 2989 dsl_pool_undirty_space(dp, delta, zio->io_txg); 2990 } 2991 2992 /* ARGSUSED */ 2993 static void 2994 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb) 2995 { 2996 dmu_buf_impl_t *db = vdb; 2997 blkptr_t *bp_orig = &zio->io_bp_orig; 2998 blkptr_t *bp = db->db_blkptr; 2999 objset_t *os = db->db_objset; 3000 dmu_tx_t *tx = os->os_synctx; 3001 dbuf_dirty_record_t **drp, *dr; 3002 3003 ASSERT0(zio->io_error); 3004 ASSERT(db->db_blkptr == bp); 3005 3006 /* 3007 * For nopwrites and rewrites we ensure that the bp matches our 3008 * original and bypass all the accounting. 3009 */ 3010 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) { 3011 ASSERT(BP_EQUAL(bp, bp_orig)); 3012 } else { 3013 dsl_dataset_t *ds = os->os_dsl_dataset; 3014 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE); 3015 dsl_dataset_block_born(ds, bp, tx); 3016 } 3017 3018 mutex_enter(&db->db_mtx); 3019 3020 DBUF_VERIFY(db); 3021 3022 drp = &db->db_last_dirty; 3023 while ((dr = *drp) != db->db_data_pending) 3024 drp = &dr->dr_next; 3025 ASSERT(!list_link_active(&dr->dr_dirty_node)); 3026 ASSERT(dr->dr_dbuf == db); 3027 ASSERT(dr->dr_next == NULL); 3028 *drp = dr->dr_next; 3029 3030 #ifdef ZFS_DEBUG 3031 if (db->db_blkid == DMU_SPILL_BLKID) { 3032 dnode_t *dn; 3033 3034 DB_DNODE_ENTER(db); 3035 dn = DB_DNODE(db); 3036 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 3037 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 3038 db->db_blkptr == &dn->dn_phys->dn_spill); 3039 DB_DNODE_EXIT(db); 3040 } 3041 #endif 3042 3043 if (db->db_level == 0) { 3044 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 3045 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN); 3046 if (db->db_state != DB_NOFILL) { 3047 if (dr->dt.dl.dr_data != db->db_buf) 3048 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 3049 db)); 3050 else if (!arc_released(db->db_buf)) 3051 arc_set_callback(db->db_buf, dbuf_do_evict, db); 3052 } 3053 } else { 3054 dnode_t *dn; 3055 3056 DB_DNODE_ENTER(db); 3057 dn = DB_DNODE(db); 3058 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 3059 ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift); 3060 if (!BP_IS_HOLE(db->db_blkptr)) { 3061 int epbs = 3062 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 3063 ASSERT3U(db->db_blkid, <=, 3064 dn->dn_phys->dn_maxblkid >> (db->db_level * epbs)); 3065 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, 3066 db->db.db_size); 3067 if (!arc_released(db->db_buf)) 3068 arc_set_callback(db->db_buf, dbuf_do_evict, db); 3069 } 3070 DB_DNODE_EXIT(db); 3071 mutex_destroy(&dr->dt.di.dr_mtx); 3072 list_destroy(&dr->dt.di.dr_children); 3073 } 3074 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 3075 3076 cv_broadcast(&db->db_changed); 3077 ASSERT(db->db_dirtycnt > 0); 3078 db->db_dirtycnt -= 1; 3079 db->db_data_pending = NULL; 3080 dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg); 3081 } 3082 3083 static void 3084 dbuf_write_nofill_ready(zio_t *zio) 3085 { 3086 dbuf_write_ready(zio, NULL, zio->io_private); 3087 } 3088 3089 static void 3090 dbuf_write_nofill_done(zio_t *zio) 3091 { 3092 dbuf_write_done(zio, NULL, zio->io_private); 3093 } 3094 3095 static void 3096 dbuf_write_override_ready(zio_t *zio) 3097 { 3098 dbuf_dirty_record_t *dr = zio->io_private; 3099 dmu_buf_impl_t *db = dr->dr_dbuf; 3100 3101 dbuf_write_ready(zio, NULL, db); 3102 } 3103 3104 static void 3105 dbuf_write_override_done(zio_t *zio) 3106 { 3107 dbuf_dirty_record_t *dr = zio->io_private; 3108 dmu_buf_impl_t *db = dr->dr_dbuf; 3109 blkptr_t *obp = &dr->dt.dl.dr_overridden_by; 3110 3111 mutex_enter(&db->db_mtx); 3112 if (!BP_EQUAL(zio->io_bp, obp)) { 3113 if (!BP_IS_HOLE(obp)) 3114 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp); 3115 arc_release(dr->dt.dl.dr_data, db); 3116 } 3117 mutex_exit(&db->db_mtx); 3118 3119 dbuf_write_done(zio, NULL, db); 3120 } 3121 3122 /* Issue I/O to commit a dirty buffer to disk. */ 3123 static void 3124 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) 3125 { 3126 dmu_buf_impl_t *db = dr->dr_dbuf; 3127 dnode_t *dn; 3128 objset_t *os; 3129 dmu_buf_impl_t *parent = db->db_parent; 3130 uint64_t txg = tx->tx_txg; 3131 zbookmark_phys_t zb; 3132 zio_prop_t zp; 3133 zio_t *zio; 3134 int wp_flag = 0; 3135 3136 DB_DNODE_ENTER(db); 3137 dn = DB_DNODE(db); 3138 os = dn->dn_objset; 3139 3140 if (db->db_state != DB_NOFILL) { 3141 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) { 3142 /* 3143 * Private object buffers are released here rather 3144 * than in dbuf_dirty() since they are only modified 3145 * in the syncing context and we don't want the 3146 * overhead of making multiple copies of the data. 3147 */ 3148 if (BP_IS_HOLE(db->db_blkptr)) { 3149 arc_buf_thaw(data); 3150 } else { 3151 dbuf_release_bp(db); 3152 } 3153 } 3154 } 3155 3156 if (parent != dn->dn_dbuf) { 3157 /* Our parent is an indirect block. */ 3158 /* We have a dirty parent that has been scheduled for write. */ 3159 ASSERT(parent && parent->db_data_pending); 3160 /* Our parent's buffer is one level closer to the dnode. */ 3161 ASSERT(db->db_level == parent->db_level-1); 3162 /* 3163 * We're about to modify our parent's db_data by modifying 3164 * our block pointer, so the parent must be released. 3165 */ 3166 ASSERT(arc_released(parent->db_buf)); 3167 zio = parent->db_data_pending->dr_zio; 3168 } else { 3169 /* Our parent is the dnode itself. */ 3170 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && 3171 db->db_blkid != DMU_SPILL_BLKID) || 3172 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); 3173 if (db->db_blkid != DMU_SPILL_BLKID) 3174 ASSERT3P(db->db_blkptr, ==, 3175 &dn->dn_phys->dn_blkptr[db->db_blkid]); 3176 zio = dn->dn_zio; 3177 } 3178 3179 ASSERT(db->db_level == 0 || data == db->db_buf); 3180 ASSERT3U(db->db_blkptr->blk_birth, <=, txg); 3181 ASSERT(zio); 3182 3183 SET_BOOKMARK(&zb, os->os_dsl_dataset ? 3184 os->os_dsl_dataset->ds_object : DMU_META_OBJSET, 3185 db->db.db_object, db->db_level, db->db_blkid); 3186 3187 if (db->db_blkid == DMU_SPILL_BLKID) 3188 wp_flag = WP_SPILL; 3189 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0; 3190 3191 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp); 3192 DB_DNODE_EXIT(db); 3193 3194 if (db->db_level == 0 && 3195 dr->dt.dl.dr_override_state == DR_OVERRIDDEN) { 3196 /* 3197 * The BP for this block has been provided by open context 3198 * (by dmu_sync() or dmu_buf_write_embedded()). 3199 */ 3200 void *contents = (data != NULL) ? data->b_data : NULL; 3201 3202 dr->dr_zio = zio_write(zio, os->os_spa, txg, 3203 db->db_blkptr, contents, db->db.db_size, &zp, 3204 dbuf_write_override_ready, NULL, dbuf_write_override_done, 3205 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 3206 mutex_enter(&db->db_mtx); 3207 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 3208 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by, 3209 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite); 3210 mutex_exit(&db->db_mtx); 3211 } else if (db->db_state == DB_NOFILL) { 3212 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF || 3213 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY); 3214 dr->dr_zio = zio_write(zio, os->os_spa, txg, 3215 db->db_blkptr, NULL, db->db.db_size, &zp, 3216 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db, 3217 ZIO_PRIORITY_ASYNC_WRITE, 3218 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb); 3219 } else { 3220 ASSERT(arc_released(data)); 3221 dr->dr_zio = arc_write(zio, os->os_spa, txg, 3222 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), 3223 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready, 3224 dbuf_write_physdone, dbuf_write_done, db, 3225 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 3226 } 3227 } 3228