1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 24 * Copyright (c) 2012, 2015 by Delphix. All rights reserved. 25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved. 26 * Copyright (c) 2013, Joyent, Inc. All rights reserved. 27 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. 28 */ 29 30 #include <sys/zfs_context.h> 31 #include <sys/dmu.h> 32 #include <sys/dmu_send.h> 33 #include <sys/dmu_impl.h> 34 #include <sys/dbuf.h> 35 #include <sys/dmu_objset.h> 36 #include <sys/dsl_dataset.h> 37 #include <sys/dsl_dir.h> 38 #include <sys/dmu_tx.h> 39 #include <sys/spa.h> 40 #include <sys/zio.h> 41 #include <sys/dmu_zfetch.h> 42 #include <sys/sa.h> 43 #include <sys/sa_impl.h> 44 #include <sys/zfeature.h> 45 #include <sys/blkptr.h> 46 #include <sys/range_tree.h> 47 48 /* 49 * Number of times that zfs_free_range() took the slow path while doing 50 * a zfs receive. A nonzero value indicates a potential performance problem. 51 */ 52 uint64_t zfs_free_range_recv_miss; 53 54 static void dbuf_destroy(dmu_buf_impl_t *db); 55 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 56 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx); 57 58 #ifndef __lint 59 extern inline void dmu_buf_init_user(dmu_buf_user_t *dbu, 60 dmu_buf_evict_func_t *evict_func, dmu_buf_t **clear_on_evict_dbufp); 61 #endif /* ! __lint */ 62 63 /* 64 * Global data structures and functions for the dbuf cache. 65 */ 66 static kmem_cache_t *dbuf_cache; 67 static taskq_t *dbu_evict_taskq; 68 69 /* ARGSUSED */ 70 static int 71 dbuf_cons(void *vdb, void *unused, int kmflag) 72 { 73 dmu_buf_impl_t *db = vdb; 74 bzero(db, sizeof (dmu_buf_impl_t)); 75 76 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL); 77 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL); 78 refcount_create(&db->db_holds); 79 80 return (0); 81 } 82 83 /* ARGSUSED */ 84 static void 85 dbuf_dest(void *vdb, void *unused) 86 { 87 dmu_buf_impl_t *db = vdb; 88 mutex_destroy(&db->db_mtx); 89 cv_destroy(&db->db_changed); 90 refcount_destroy(&db->db_holds); 91 } 92 93 /* 94 * dbuf hash table routines 95 */ 96 static dbuf_hash_table_t dbuf_hash_table; 97 98 static uint64_t dbuf_hash_count; 99 100 static uint64_t 101 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid) 102 { 103 uintptr_t osv = (uintptr_t)os; 104 uint64_t crc = -1ULL; 105 106 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); 107 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF]; 108 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF]; 109 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF]; 110 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF]; 111 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF]; 112 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF]; 113 114 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16); 115 116 return (crc); 117 } 118 119 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid); 120 121 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \ 122 ((dbuf)->db.db_object == (obj) && \ 123 (dbuf)->db_objset == (os) && \ 124 (dbuf)->db_level == (level) && \ 125 (dbuf)->db_blkid == (blkid)) 126 127 dmu_buf_impl_t * 128 dbuf_find(objset_t *os, uint64_t obj, uint8_t level, uint64_t blkid) 129 { 130 dbuf_hash_table_t *h = &dbuf_hash_table; 131 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 132 uint64_t idx = hv & h->hash_table_mask; 133 dmu_buf_impl_t *db; 134 135 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 136 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) { 137 if (DBUF_EQUAL(db, os, obj, level, blkid)) { 138 mutex_enter(&db->db_mtx); 139 if (db->db_state != DB_EVICTING) { 140 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 141 return (db); 142 } 143 mutex_exit(&db->db_mtx); 144 } 145 } 146 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 147 return (NULL); 148 } 149 150 static dmu_buf_impl_t * 151 dbuf_find_bonus(objset_t *os, uint64_t object) 152 { 153 dnode_t *dn; 154 dmu_buf_impl_t *db = NULL; 155 156 if (dnode_hold(os, object, FTAG, &dn) == 0) { 157 rw_enter(&dn->dn_struct_rwlock, RW_READER); 158 if (dn->dn_bonus != NULL) { 159 db = dn->dn_bonus; 160 mutex_enter(&db->db_mtx); 161 } 162 rw_exit(&dn->dn_struct_rwlock); 163 dnode_rele(dn, FTAG); 164 } 165 return (db); 166 } 167 168 /* 169 * Insert an entry into the hash table. If there is already an element 170 * equal to elem in the hash table, then the already existing element 171 * will be returned and the new element will not be inserted. 172 * Otherwise returns NULL. 173 */ 174 static dmu_buf_impl_t * 175 dbuf_hash_insert(dmu_buf_impl_t *db) 176 { 177 dbuf_hash_table_t *h = &dbuf_hash_table; 178 objset_t *os = db->db_objset; 179 uint64_t obj = db->db.db_object; 180 int level = db->db_level; 181 uint64_t blkid = db->db_blkid; 182 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 183 uint64_t idx = hv & h->hash_table_mask; 184 dmu_buf_impl_t *dbf; 185 186 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 187 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) { 188 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) { 189 mutex_enter(&dbf->db_mtx); 190 if (dbf->db_state != DB_EVICTING) { 191 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 192 return (dbf); 193 } 194 mutex_exit(&dbf->db_mtx); 195 } 196 } 197 198 mutex_enter(&db->db_mtx); 199 db->db_hash_next = h->hash_table[idx]; 200 h->hash_table[idx] = db; 201 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 202 atomic_inc_64(&dbuf_hash_count); 203 204 return (NULL); 205 } 206 207 /* 208 * Remove an entry from the hash table. It must be in the EVICTING state. 209 */ 210 static void 211 dbuf_hash_remove(dmu_buf_impl_t *db) 212 { 213 dbuf_hash_table_t *h = &dbuf_hash_table; 214 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object, 215 db->db_level, db->db_blkid); 216 uint64_t idx = hv & h->hash_table_mask; 217 dmu_buf_impl_t *dbf, **dbp; 218 219 /* 220 * We musn't hold db_mtx to maintain lock ordering: 221 * DBUF_HASH_MUTEX > db_mtx. 222 */ 223 ASSERT(refcount_is_zero(&db->db_holds)); 224 ASSERT(db->db_state == DB_EVICTING); 225 ASSERT(!MUTEX_HELD(&db->db_mtx)); 226 227 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 228 dbp = &h->hash_table[idx]; 229 while ((dbf = *dbp) != db) { 230 dbp = &dbf->db_hash_next; 231 ASSERT(dbf != NULL); 232 } 233 *dbp = db->db_hash_next; 234 db->db_hash_next = NULL; 235 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 236 atomic_dec_64(&dbuf_hash_count); 237 } 238 239 static arc_evict_func_t dbuf_do_evict; 240 241 typedef enum { 242 DBVU_EVICTING, 243 DBVU_NOT_EVICTING 244 } dbvu_verify_type_t; 245 246 static void 247 dbuf_verify_user(dmu_buf_impl_t *db, dbvu_verify_type_t verify_type) 248 { 249 #ifdef ZFS_DEBUG 250 int64_t holds; 251 252 if (db->db_user == NULL) 253 return; 254 255 /* Only data blocks support the attachment of user data. */ 256 ASSERT(db->db_level == 0); 257 258 /* Clients must resolve a dbuf before attaching user data. */ 259 ASSERT(db->db.db_data != NULL); 260 ASSERT3U(db->db_state, ==, DB_CACHED); 261 262 holds = refcount_count(&db->db_holds); 263 if (verify_type == DBVU_EVICTING) { 264 /* 265 * Immediate eviction occurs when holds == dirtycnt. 266 * For normal eviction buffers, holds is zero on 267 * eviction, except when dbuf_fix_old_data() calls 268 * dbuf_clear_data(). However, the hold count can grow 269 * during eviction even though db_mtx is held (see 270 * dmu_bonus_hold() for an example), so we can only 271 * test the generic invariant that holds >= dirtycnt. 272 */ 273 ASSERT3U(holds, >=, db->db_dirtycnt); 274 } else { 275 if (db->db_user_immediate_evict == TRUE) 276 ASSERT3U(holds, >=, db->db_dirtycnt); 277 else 278 ASSERT3U(holds, >, 0); 279 } 280 #endif 281 } 282 283 static void 284 dbuf_evict_user(dmu_buf_impl_t *db) 285 { 286 dmu_buf_user_t *dbu = db->db_user; 287 288 ASSERT(MUTEX_HELD(&db->db_mtx)); 289 290 if (dbu == NULL) 291 return; 292 293 dbuf_verify_user(db, DBVU_EVICTING); 294 db->db_user = NULL; 295 296 #ifdef ZFS_DEBUG 297 if (dbu->dbu_clear_on_evict_dbufp != NULL) 298 *dbu->dbu_clear_on_evict_dbufp = NULL; 299 #endif 300 301 /* 302 * Invoke the callback from a taskq to avoid lock order reversals 303 * and limit stack depth. 304 */ 305 taskq_dispatch_ent(dbu_evict_taskq, dbu->dbu_evict_func, dbu, 0, 306 &dbu->dbu_tqent); 307 } 308 309 boolean_t 310 dbuf_is_metadata(dmu_buf_impl_t *db) 311 { 312 if (db->db_level > 0) { 313 return (B_TRUE); 314 } else { 315 boolean_t is_metadata; 316 317 DB_DNODE_ENTER(db); 318 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type); 319 DB_DNODE_EXIT(db); 320 321 return (is_metadata); 322 } 323 } 324 325 void 326 dbuf_evict(dmu_buf_impl_t *db) 327 { 328 ASSERT(MUTEX_HELD(&db->db_mtx)); 329 ASSERT(db->db_buf == NULL); 330 ASSERT(db->db_data_pending == NULL); 331 332 dbuf_clear(db); 333 dbuf_destroy(db); 334 } 335 336 void 337 dbuf_init(void) 338 { 339 uint64_t hsize = 1ULL << 16; 340 dbuf_hash_table_t *h = &dbuf_hash_table; 341 int i; 342 343 /* 344 * The hash table is big enough to fill all of physical memory 345 * with an average 4K block size. The table will take up 346 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers). 347 */ 348 while (hsize * 4096 < physmem * PAGESIZE) 349 hsize <<= 1; 350 351 retry: 352 h->hash_table_mask = hsize - 1; 353 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP); 354 if (h->hash_table == NULL) { 355 /* XXX - we should really return an error instead of assert */ 356 ASSERT(hsize > (1ULL << 10)); 357 hsize >>= 1; 358 goto retry; 359 } 360 361 dbuf_cache = kmem_cache_create("dmu_buf_impl_t", 362 sizeof (dmu_buf_impl_t), 363 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0); 364 365 for (i = 0; i < DBUF_MUTEXES; i++) 366 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL); 367 368 /* 369 * All entries are queued via taskq_dispatch_ent(), so min/maxalloc 370 * configuration is not required. 371 */ 372 dbu_evict_taskq = taskq_create("dbu_evict", 1, minclsyspri, 0, 0, 0); 373 } 374 375 void 376 dbuf_fini(void) 377 { 378 dbuf_hash_table_t *h = &dbuf_hash_table; 379 int i; 380 381 for (i = 0; i < DBUF_MUTEXES; i++) 382 mutex_destroy(&h->hash_mutexes[i]); 383 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *)); 384 kmem_cache_destroy(dbuf_cache); 385 taskq_destroy(dbu_evict_taskq); 386 } 387 388 /* 389 * Other stuff. 390 */ 391 392 #ifdef ZFS_DEBUG 393 static void 394 dbuf_verify(dmu_buf_impl_t *db) 395 { 396 dnode_t *dn; 397 dbuf_dirty_record_t *dr; 398 399 ASSERT(MUTEX_HELD(&db->db_mtx)); 400 401 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY)) 402 return; 403 404 ASSERT(db->db_objset != NULL); 405 DB_DNODE_ENTER(db); 406 dn = DB_DNODE(db); 407 if (dn == NULL) { 408 ASSERT(db->db_parent == NULL); 409 ASSERT(db->db_blkptr == NULL); 410 } else { 411 ASSERT3U(db->db.db_object, ==, dn->dn_object); 412 ASSERT3P(db->db_objset, ==, dn->dn_objset); 413 ASSERT3U(db->db_level, <, dn->dn_nlevels); 414 ASSERT(db->db_blkid == DMU_BONUS_BLKID || 415 db->db_blkid == DMU_SPILL_BLKID || 416 !avl_is_empty(&dn->dn_dbufs)); 417 } 418 if (db->db_blkid == DMU_BONUS_BLKID) { 419 ASSERT(dn != NULL); 420 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 421 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID); 422 } else if (db->db_blkid == DMU_SPILL_BLKID) { 423 ASSERT(dn != NULL); 424 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 425 ASSERT0(db->db.db_offset); 426 } else { 427 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size); 428 } 429 430 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next) 431 ASSERT(dr->dr_dbuf == db); 432 433 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next) 434 ASSERT(dr->dr_dbuf == db); 435 436 /* 437 * We can't assert that db_size matches dn_datablksz because it 438 * can be momentarily different when another thread is doing 439 * dnode_set_blksz(). 440 */ 441 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) { 442 dr = db->db_data_pending; 443 /* 444 * It should only be modified in syncing context, so 445 * make sure we only have one copy of the data. 446 */ 447 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf); 448 } 449 450 /* verify db->db_blkptr */ 451 if (db->db_blkptr) { 452 if (db->db_parent == dn->dn_dbuf) { 453 /* db is pointed to by the dnode */ 454 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */ 455 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object)) 456 ASSERT(db->db_parent == NULL); 457 else 458 ASSERT(db->db_parent != NULL); 459 if (db->db_blkid != DMU_SPILL_BLKID) 460 ASSERT3P(db->db_blkptr, ==, 461 &dn->dn_phys->dn_blkptr[db->db_blkid]); 462 } else { 463 /* db is pointed to by an indirect block */ 464 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT; 465 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1); 466 ASSERT3U(db->db_parent->db.db_object, ==, 467 db->db.db_object); 468 /* 469 * dnode_grow_indblksz() can make this fail if we don't 470 * have the struct_rwlock. XXX indblksz no longer 471 * grows. safe to do this now? 472 */ 473 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 474 ASSERT3P(db->db_blkptr, ==, 475 ((blkptr_t *)db->db_parent->db.db_data + 476 db->db_blkid % epb)); 477 } 478 } 479 } 480 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) && 481 (db->db_buf == NULL || db->db_buf->b_data) && 482 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID && 483 db->db_state != DB_FILL && !dn->dn_free_txg) { 484 /* 485 * If the blkptr isn't set but they have nonzero data, 486 * it had better be dirty, otherwise we'll lose that 487 * data when we evict this buffer. 488 */ 489 if (db->db_dirtycnt == 0) { 490 uint64_t *buf = db->db.db_data; 491 int i; 492 493 for (i = 0; i < db->db.db_size >> 3; i++) { 494 ASSERT(buf[i] == 0); 495 } 496 } 497 } 498 DB_DNODE_EXIT(db); 499 } 500 #endif 501 502 static void 503 dbuf_clear_data(dmu_buf_impl_t *db) 504 { 505 ASSERT(MUTEX_HELD(&db->db_mtx)); 506 dbuf_evict_user(db); 507 db->db_buf = NULL; 508 db->db.db_data = NULL; 509 if (db->db_state != DB_NOFILL) 510 db->db_state = DB_UNCACHED; 511 } 512 513 static void 514 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf) 515 { 516 ASSERT(MUTEX_HELD(&db->db_mtx)); 517 ASSERT(buf != NULL); 518 519 db->db_buf = buf; 520 ASSERT(buf->b_data != NULL); 521 db->db.db_data = buf->b_data; 522 if (!arc_released(buf)) 523 arc_set_callback(buf, dbuf_do_evict, db); 524 } 525 526 /* 527 * Loan out an arc_buf for read. Return the loaned arc_buf. 528 */ 529 arc_buf_t * 530 dbuf_loan_arcbuf(dmu_buf_impl_t *db) 531 { 532 arc_buf_t *abuf; 533 534 mutex_enter(&db->db_mtx); 535 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) { 536 int blksz = db->db.db_size; 537 spa_t *spa = db->db_objset->os_spa; 538 539 mutex_exit(&db->db_mtx); 540 abuf = arc_loan_buf(spa, blksz); 541 bcopy(db->db.db_data, abuf->b_data, blksz); 542 } else { 543 abuf = db->db_buf; 544 arc_loan_inuse_buf(abuf, db); 545 dbuf_clear_data(db); 546 mutex_exit(&db->db_mtx); 547 } 548 return (abuf); 549 } 550 551 /* 552 * Calculate which level n block references the data at the level 0 offset 553 * provided. 554 */ 555 uint64_t 556 dbuf_whichblock(dnode_t *dn, int64_t level, uint64_t offset) 557 { 558 if (dn->dn_datablkshift != 0 && dn->dn_indblkshift != 0) { 559 /* 560 * The level n blkid is equal to the level 0 blkid divided by 561 * the number of level 0s in a level n block. 562 * 563 * The level 0 blkid is offset >> datablkshift = 564 * offset / 2^datablkshift. 565 * 566 * The number of level 0s in a level n is the number of block 567 * pointers in an indirect block, raised to the power of level. 568 * This is 2^(indblkshift - SPA_BLKPTRSHIFT)^level = 569 * 2^(level*(indblkshift - SPA_BLKPTRSHIFT)). 570 * 571 * Thus, the level n blkid is: offset / 572 * ((2^datablkshift)*(2^(level*(indblkshift - SPA_BLKPTRSHIFT))) 573 * = offset / 2^(datablkshift + level * 574 * (indblkshift - SPA_BLKPTRSHIFT)) 575 * = offset >> (datablkshift + level * 576 * (indblkshift - SPA_BLKPTRSHIFT)) 577 */ 578 return (offset >> (dn->dn_datablkshift + level * 579 (dn->dn_indblkshift - SPA_BLKPTRSHIFT))); 580 } else { 581 ASSERT3U(offset, <, dn->dn_datablksz); 582 return (0); 583 } 584 } 585 586 static void 587 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb) 588 { 589 dmu_buf_impl_t *db = vdb; 590 591 mutex_enter(&db->db_mtx); 592 ASSERT3U(db->db_state, ==, DB_READ); 593 /* 594 * All reads are synchronous, so we must have a hold on the dbuf 595 */ 596 ASSERT(refcount_count(&db->db_holds) > 0); 597 ASSERT(db->db_buf == NULL); 598 ASSERT(db->db.db_data == NULL); 599 if (db->db_level == 0 && db->db_freed_in_flight) { 600 /* we were freed in flight; disregard any error */ 601 arc_release(buf, db); 602 bzero(buf->b_data, db->db.db_size); 603 arc_buf_freeze(buf); 604 db->db_freed_in_flight = FALSE; 605 dbuf_set_data(db, buf); 606 db->db_state = DB_CACHED; 607 } else if (zio == NULL || zio->io_error == 0) { 608 dbuf_set_data(db, buf); 609 db->db_state = DB_CACHED; 610 } else { 611 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 612 ASSERT3P(db->db_buf, ==, NULL); 613 VERIFY(arc_buf_remove_ref(buf, db)); 614 db->db_state = DB_UNCACHED; 615 } 616 cv_broadcast(&db->db_changed); 617 dbuf_rele_and_unlock(db, NULL); 618 } 619 620 static void 621 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags) 622 { 623 dnode_t *dn; 624 zbookmark_phys_t zb; 625 arc_flags_t aflags = ARC_FLAG_NOWAIT; 626 627 DB_DNODE_ENTER(db); 628 dn = DB_DNODE(db); 629 ASSERT(!refcount_is_zero(&db->db_holds)); 630 /* We need the struct_rwlock to prevent db_blkptr from changing. */ 631 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 632 ASSERT(MUTEX_HELD(&db->db_mtx)); 633 ASSERT(db->db_state == DB_UNCACHED); 634 ASSERT(db->db_buf == NULL); 635 636 if (db->db_blkid == DMU_BONUS_BLKID) { 637 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen); 638 639 ASSERT3U(bonuslen, <=, db->db.db_size); 640 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN); 641 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 642 if (bonuslen < DN_MAX_BONUSLEN) 643 bzero(db->db.db_data, DN_MAX_BONUSLEN); 644 if (bonuslen) 645 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen); 646 DB_DNODE_EXIT(db); 647 db->db_state = DB_CACHED; 648 mutex_exit(&db->db_mtx); 649 return; 650 } 651 652 /* 653 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync() 654 * processes the delete record and clears the bp while we are waiting 655 * for the dn_mtx (resulting in a "no" from block_freed). 656 */ 657 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) || 658 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) || 659 BP_IS_HOLE(db->db_blkptr)))) { 660 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 661 662 DB_DNODE_EXIT(db); 663 dbuf_set_data(db, arc_buf_alloc(db->db_objset->os_spa, 664 db->db.db_size, db, type)); 665 bzero(db->db.db_data, db->db.db_size); 666 db->db_state = DB_CACHED; 667 *flags |= DB_RF_CACHED; 668 mutex_exit(&db->db_mtx); 669 return; 670 } 671 672 DB_DNODE_EXIT(db); 673 674 db->db_state = DB_READ; 675 mutex_exit(&db->db_mtx); 676 677 if (DBUF_IS_L2CACHEABLE(db)) 678 aflags |= ARC_FLAG_L2CACHE; 679 if (DBUF_IS_L2COMPRESSIBLE(db)) 680 aflags |= ARC_FLAG_L2COMPRESS; 681 682 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ? 683 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET, 684 db->db.db_object, db->db_level, db->db_blkid); 685 686 dbuf_add_ref(db, NULL); 687 688 (void) arc_read(zio, db->db_objset->os_spa, db->db_blkptr, 689 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ, 690 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED, 691 &aflags, &zb); 692 if (aflags & ARC_FLAG_CACHED) 693 *flags |= DB_RF_CACHED; 694 } 695 696 int 697 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) 698 { 699 int err = 0; 700 boolean_t havepzio = (zio != NULL); 701 boolean_t prefetch; 702 dnode_t *dn; 703 704 /* 705 * We don't have to hold the mutex to check db_state because it 706 * can't be freed while we have a hold on the buffer. 707 */ 708 ASSERT(!refcount_is_zero(&db->db_holds)); 709 710 if (db->db_state == DB_NOFILL) 711 return (SET_ERROR(EIO)); 712 713 DB_DNODE_ENTER(db); 714 dn = DB_DNODE(db); 715 if ((flags & DB_RF_HAVESTRUCT) == 0) 716 rw_enter(&dn->dn_struct_rwlock, RW_READER); 717 718 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 719 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL && 720 DBUF_IS_CACHEABLE(db); 721 722 mutex_enter(&db->db_mtx); 723 if (db->db_state == DB_CACHED) { 724 mutex_exit(&db->db_mtx); 725 if (prefetch) 726 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 727 db->db.db_size, TRUE); 728 if ((flags & DB_RF_HAVESTRUCT) == 0) 729 rw_exit(&dn->dn_struct_rwlock); 730 DB_DNODE_EXIT(db); 731 } else if (db->db_state == DB_UNCACHED) { 732 spa_t *spa = dn->dn_objset->os_spa; 733 734 if (zio == NULL) 735 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL); 736 dbuf_read_impl(db, zio, &flags); 737 738 /* dbuf_read_impl has dropped db_mtx for us */ 739 740 if (prefetch) 741 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 742 db->db.db_size, flags & DB_RF_CACHED); 743 744 if ((flags & DB_RF_HAVESTRUCT) == 0) 745 rw_exit(&dn->dn_struct_rwlock); 746 DB_DNODE_EXIT(db); 747 748 if (!havepzio) 749 err = zio_wait(zio); 750 } else { 751 /* 752 * Another reader came in while the dbuf was in flight 753 * between UNCACHED and CACHED. Either a writer will finish 754 * writing the buffer (sending the dbuf to CACHED) or the 755 * first reader's request will reach the read_done callback 756 * and send the dbuf to CACHED. Otherwise, a failure 757 * occurred and the dbuf went to UNCACHED. 758 */ 759 mutex_exit(&db->db_mtx); 760 if (prefetch) 761 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 762 db->db.db_size, TRUE); 763 if ((flags & DB_RF_HAVESTRUCT) == 0) 764 rw_exit(&dn->dn_struct_rwlock); 765 DB_DNODE_EXIT(db); 766 767 /* Skip the wait per the caller's request. */ 768 mutex_enter(&db->db_mtx); 769 if ((flags & DB_RF_NEVERWAIT) == 0) { 770 while (db->db_state == DB_READ || 771 db->db_state == DB_FILL) { 772 ASSERT(db->db_state == DB_READ || 773 (flags & DB_RF_HAVESTRUCT) == 0); 774 DTRACE_PROBE2(blocked__read, dmu_buf_impl_t *, 775 db, zio_t *, zio); 776 cv_wait(&db->db_changed, &db->db_mtx); 777 } 778 if (db->db_state == DB_UNCACHED) 779 err = SET_ERROR(EIO); 780 } 781 mutex_exit(&db->db_mtx); 782 } 783 784 ASSERT(err || havepzio || db->db_state == DB_CACHED); 785 return (err); 786 } 787 788 static void 789 dbuf_noread(dmu_buf_impl_t *db) 790 { 791 ASSERT(!refcount_is_zero(&db->db_holds)); 792 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 793 mutex_enter(&db->db_mtx); 794 while (db->db_state == DB_READ || db->db_state == DB_FILL) 795 cv_wait(&db->db_changed, &db->db_mtx); 796 if (db->db_state == DB_UNCACHED) { 797 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 798 spa_t *spa = db->db_objset->os_spa; 799 800 ASSERT(db->db_buf == NULL); 801 ASSERT(db->db.db_data == NULL); 802 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type)); 803 db->db_state = DB_FILL; 804 } else if (db->db_state == DB_NOFILL) { 805 dbuf_clear_data(db); 806 } else { 807 ASSERT3U(db->db_state, ==, DB_CACHED); 808 } 809 mutex_exit(&db->db_mtx); 810 } 811 812 /* 813 * This is our just-in-time copy function. It makes a copy of 814 * buffers, that have been modified in a previous transaction 815 * group, before we modify them in the current active group. 816 * 817 * This function is used in two places: when we are dirtying a 818 * buffer for the first time in a txg, and when we are freeing 819 * a range in a dnode that includes this buffer. 820 * 821 * Note that when we are called from dbuf_free_range() we do 822 * not put a hold on the buffer, we just traverse the active 823 * dbuf list for the dnode. 824 */ 825 static void 826 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg) 827 { 828 dbuf_dirty_record_t *dr = db->db_last_dirty; 829 830 ASSERT(MUTEX_HELD(&db->db_mtx)); 831 ASSERT(db->db.db_data != NULL); 832 ASSERT(db->db_level == 0); 833 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT); 834 835 if (dr == NULL || 836 (dr->dt.dl.dr_data != 837 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf))) 838 return; 839 840 /* 841 * If the last dirty record for this dbuf has not yet synced 842 * and its referencing the dbuf data, either: 843 * reset the reference to point to a new copy, 844 * or (if there a no active holders) 845 * just null out the current db_data pointer. 846 */ 847 ASSERT(dr->dr_txg >= txg - 2); 848 if (db->db_blkid == DMU_BONUS_BLKID) { 849 /* Note that the data bufs here are zio_bufs */ 850 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN); 851 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 852 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN); 853 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) { 854 int size = db->db.db_size; 855 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 856 spa_t *spa = db->db_objset->os_spa; 857 858 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type); 859 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size); 860 } else { 861 dbuf_clear_data(db); 862 } 863 } 864 865 void 866 dbuf_unoverride(dbuf_dirty_record_t *dr) 867 { 868 dmu_buf_impl_t *db = dr->dr_dbuf; 869 blkptr_t *bp = &dr->dt.dl.dr_overridden_by; 870 uint64_t txg = dr->dr_txg; 871 872 ASSERT(MUTEX_HELD(&db->db_mtx)); 873 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC); 874 ASSERT(db->db_level == 0); 875 876 if (db->db_blkid == DMU_BONUS_BLKID || 877 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN) 878 return; 879 880 ASSERT(db->db_data_pending != dr); 881 882 /* free this block */ 883 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite) 884 zio_free(db->db_objset->os_spa, txg, bp); 885 886 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 887 dr->dt.dl.dr_nopwrite = B_FALSE; 888 889 /* 890 * Release the already-written buffer, so we leave it in 891 * a consistent dirty state. Note that all callers are 892 * modifying the buffer, so they will immediately do 893 * another (redundant) arc_release(). Therefore, leave 894 * the buf thawed to save the effort of freezing & 895 * immediately re-thawing it. 896 */ 897 arc_release(dr->dt.dl.dr_data, db); 898 } 899 900 /* 901 * Evict (if its unreferenced) or clear (if its referenced) any level-0 902 * data blocks in the free range, so that any future readers will find 903 * empty blocks. 904 * 905 * This is a no-op if the dataset is in the middle of an incremental 906 * receive; see comment below for details. 907 */ 908 void 909 dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, 910 dmu_tx_t *tx) 911 { 912 dmu_buf_impl_t db_search; 913 dmu_buf_impl_t *db, *db_next; 914 uint64_t txg = tx->tx_txg; 915 avl_index_t where; 916 917 if (end_blkid > dn->dn_maxblkid && (end_blkid != DMU_SPILL_BLKID)) 918 end_blkid = dn->dn_maxblkid; 919 dprintf_dnode(dn, "start=%llu end=%llu\n", start_blkid, end_blkid); 920 921 db_search.db_level = 0; 922 db_search.db_blkid = start_blkid; 923 db_search.db_state = DB_SEARCH; 924 925 mutex_enter(&dn->dn_dbufs_mtx); 926 if (start_blkid >= dn->dn_unlisted_l0_blkid) { 927 /* There can't be any dbufs in this range; no need to search. */ 928 #ifdef DEBUG 929 db = avl_find(&dn->dn_dbufs, &db_search, &where); 930 ASSERT3P(db, ==, NULL); 931 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 932 ASSERT(db == NULL || db->db_level > 0); 933 #endif 934 mutex_exit(&dn->dn_dbufs_mtx); 935 return; 936 } else if (dmu_objset_is_receiving(dn->dn_objset)) { 937 /* 938 * If we are receiving, we expect there to be no dbufs in 939 * the range to be freed, because receive modifies each 940 * block at most once, and in offset order. If this is 941 * not the case, it can lead to performance problems, 942 * so note that we unexpectedly took the slow path. 943 */ 944 atomic_inc_64(&zfs_free_range_recv_miss); 945 } 946 947 db = avl_find(&dn->dn_dbufs, &db_search, &where); 948 ASSERT3P(db, ==, NULL); 949 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 950 951 for (; db != NULL; db = db_next) { 952 db_next = AVL_NEXT(&dn->dn_dbufs, db); 953 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 954 955 if (db->db_level != 0 || db->db_blkid > end_blkid) { 956 break; 957 } 958 ASSERT3U(db->db_blkid, >=, start_blkid); 959 960 /* found a level 0 buffer in the range */ 961 mutex_enter(&db->db_mtx); 962 if (dbuf_undirty(db, tx)) { 963 /* mutex has been dropped and dbuf destroyed */ 964 continue; 965 } 966 967 if (db->db_state == DB_UNCACHED || 968 db->db_state == DB_NOFILL || 969 db->db_state == DB_EVICTING) { 970 ASSERT(db->db.db_data == NULL); 971 mutex_exit(&db->db_mtx); 972 continue; 973 } 974 if (db->db_state == DB_READ || db->db_state == DB_FILL) { 975 /* will be handled in dbuf_read_done or dbuf_rele */ 976 db->db_freed_in_flight = TRUE; 977 mutex_exit(&db->db_mtx); 978 continue; 979 } 980 if (refcount_count(&db->db_holds) == 0) { 981 ASSERT(db->db_buf); 982 dbuf_clear(db); 983 continue; 984 } 985 /* The dbuf is referenced */ 986 987 if (db->db_last_dirty != NULL) { 988 dbuf_dirty_record_t *dr = db->db_last_dirty; 989 990 if (dr->dr_txg == txg) { 991 /* 992 * This buffer is "in-use", re-adjust the file 993 * size to reflect that this buffer may 994 * contain new data when we sync. 995 */ 996 if (db->db_blkid != DMU_SPILL_BLKID && 997 db->db_blkid > dn->dn_maxblkid) 998 dn->dn_maxblkid = db->db_blkid; 999 dbuf_unoverride(dr); 1000 } else { 1001 /* 1002 * This dbuf is not dirty in the open context. 1003 * Either uncache it (if its not referenced in 1004 * the open context) or reset its contents to 1005 * empty. 1006 */ 1007 dbuf_fix_old_data(db, txg); 1008 } 1009 } 1010 /* clear the contents if its cached */ 1011 if (db->db_state == DB_CACHED) { 1012 ASSERT(db->db.db_data != NULL); 1013 arc_release(db->db_buf, db); 1014 bzero(db->db.db_data, db->db.db_size); 1015 arc_buf_freeze(db->db_buf); 1016 } 1017 1018 mutex_exit(&db->db_mtx); 1019 } 1020 mutex_exit(&dn->dn_dbufs_mtx); 1021 } 1022 1023 static int 1024 dbuf_block_freeable(dmu_buf_impl_t *db) 1025 { 1026 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset; 1027 uint64_t birth_txg = 0; 1028 1029 /* 1030 * We don't need any locking to protect db_blkptr: 1031 * If it's syncing, then db_last_dirty will be set 1032 * so we'll ignore db_blkptr. 1033 * 1034 * This logic ensures that only block births for 1035 * filled blocks are considered. 1036 */ 1037 ASSERT(MUTEX_HELD(&db->db_mtx)); 1038 if (db->db_last_dirty && (db->db_blkptr == NULL || 1039 !BP_IS_HOLE(db->db_blkptr))) { 1040 birth_txg = db->db_last_dirty->dr_txg; 1041 } else if (db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr)) { 1042 birth_txg = db->db_blkptr->blk_birth; 1043 } 1044 1045 /* 1046 * If this block don't exist or is in a snapshot, it can't be freed. 1047 * Don't pass the bp to dsl_dataset_block_freeable() since we 1048 * are holding the db_mtx lock and might deadlock if we are 1049 * prefetching a dedup-ed block. 1050 */ 1051 if (birth_txg != 0) 1052 return (ds == NULL || 1053 dsl_dataset_block_freeable(ds, NULL, birth_txg)); 1054 else 1055 return (B_FALSE); 1056 } 1057 1058 void 1059 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx) 1060 { 1061 arc_buf_t *buf, *obuf; 1062 int osize = db->db.db_size; 1063 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 1064 dnode_t *dn; 1065 1066 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1067 1068 DB_DNODE_ENTER(db); 1069 dn = DB_DNODE(db); 1070 1071 /* XXX does *this* func really need the lock? */ 1072 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 1073 1074 /* 1075 * This call to dmu_buf_will_dirty() with the dn_struct_rwlock held 1076 * is OK, because there can be no other references to the db 1077 * when we are changing its size, so no concurrent DB_FILL can 1078 * be happening. 1079 */ 1080 /* 1081 * XXX we should be doing a dbuf_read, checking the return 1082 * value and returning that up to our callers 1083 */ 1084 dmu_buf_will_dirty(&db->db, tx); 1085 1086 /* create the data buffer for the new block */ 1087 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type); 1088 1089 /* copy old block data to the new block */ 1090 obuf = db->db_buf; 1091 bcopy(obuf->b_data, buf->b_data, MIN(osize, size)); 1092 /* zero the remainder */ 1093 if (size > osize) 1094 bzero((uint8_t *)buf->b_data + osize, size - osize); 1095 1096 mutex_enter(&db->db_mtx); 1097 dbuf_set_data(db, buf); 1098 VERIFY(arc_buf_remove_ref(obuf, db)); 1099 db->db.db_size = size; 1100 1101 if (db->db_level == 0) { 1102 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 1103 db->db_last_dirty->dt.dl.dr_data = buf; 1104 } 1105 mutex_exit(&db->db_mtx); 1106 1107 dnode_willuse_space(dn, size-osize, tx); 1108 DB_DNODE_EXIT(db); 1109 } 1110 1111 void 1112 dbuf_release_bp(dmu_buf_impl_t *db) 1113 { 1114 objset_t *os = db->db_objset; 1115 1116 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os))); 1117 ASSERT(arc_released(os->os_phys_buf) || 1118 list_link_active(&os->os_dsl_dataset->ds_synced_link)); 1119 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf)); 1120 1121 (void) arc_release(db->db_buf, db); 1122 } 1123 1124 dbuf_dirty_record_t * 1125 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1126 { 1127 dnode_t *dn; 1128 objset_t *os; 1129 dbuf_dirty_record_t **drp, *dr; 1130 int drop_struct_lock = FALSE; 1131 boolean_t do_free_accounting = B_FALSE; 1132 int txgoff = tx->tx_txg & TXG_MASK; 1133 1134 ASSERT(tx->tx_txg != 0); 1135 ASSERT(!refcount_is_zero(&db->db_holds)); 1136 DMU_TX_DIRTY_BUF(tx, db); 1137 1138 DB_DNODE_ENTER(db); 1139 dn = DB_DNODE(db); 1140 /* 1141 * Shouldn't dirty a regular buffer in syncing context. Private 1142 * objects may be dirtied in syncing context, but only if they 1143 * were already pre-dirtied in open context. 1144 */ 1145 ASSERT(!dmu_tx_is_syncing(tx) || 1146 BP_IS_HOLE(dn->dn_objset->os_rootbp) || 1147 DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1148 dn->dn_objset->os_dsl_dataset == NULL); 1149 /* 1150 * We make this assert for private objects as well, but after we 1151 * check if we're already dirty. They are allowed to re-dirty 1152 * in syncing context. 1153 */ 1154 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1155 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1156 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1157 1158 mutex_enter(&db->db_mtx); 1159 /* 1160 * XXX make this true for indirects too? The problem is that 1161 * transactions created with dmu_tx_create_assigned() from 1162 * syncing context don't bother holding ahead. 1163 */ 1164 ASSERT(db->db_level != 0 || 1165 db->db_state == DB_CACHED || db->db_state == DB_FILL || 1166 db->db_state == DB_NOFILL); 1167 1168 mutex_enter(&dn->dn_mtx); 1169 /* 1170 * Don't set dirtyctx to SYNC if we're just modifying this as we 1171 * initialize the objset. 1172 */ 1173 if (dn->dn_dirtyctx == DN_UNDIRTIED && 1174 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) { 1175 dn->dn_dirtyctx = 1176 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN); 1177 ASSERT(dn->dn_dirtyctx_firstset == NULL); 1178 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP); 1179 } 1180 mutex_exit(&dn->dn_mtx); 1181 1182 if (db->db_blkid == DMU_SPILL_BLKID) 1183 dn->dn_have_spill = B_TRUE; 1184 1185 /* 1186 * If this buffer is already dirty, we're done. 1187 */ 1188 drp = &db->db_last_dirty; 1189 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg || 1190 db->db.db_object == DMU_META_DNODE_OBJECT); 1191 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg) 1192 drp = &dr->dr_next; 1193 if (dr && dr->dr_txg == tx->tx_txg) { 1194 DB_DNODE_EXIT(db); 1195 1196 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) { 1197 /* 1198 * If this buffer has already been written out, 1199 * we now need to reset its state. 1200 */ 1201 dbuf_unoverride(dr); 1202 if (db->db.db_object != DMU_META_DNODE_OBJECT && 1203 db->db_state != DB_NOFILL) 1204 arc_buf_thaw(db->db_buf); 1205 } 1206 mutex_exit(&db->db_mtx); 1207 return (dr); 1208 } 1209 1210 /* 1211 * Only valid if not already dirty. 1212 */ 1213 ASSERT(dn->dn_object == 0 || 1214 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1215 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1216 1217 ASSERT3U(dn->dn_nlevels, >, db->db_level); 1218 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) || 1219 dn->dn_phys->dn_nlevels > db->db_level || 1220 dn->dn_next_nlevels[txgoff] > db->db_level || 1221 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level || 1222 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level); 1223 1224 /* 1225 * We should only be dirtying in syncing context if it's the 1226 * mos or we're initializing the os or it's a special object. 1227 * However, we are allowed to dirty in syncing context provided 1228 * we already dirtied it in open context. Hence we must make 1229 * this assertion only if we're not already dirty. 1230 */ 1231 os = dn->dn_objset; 1232 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1233 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp)); 1234 ASSERT(db->db.db_size != 0); 1235 1236 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1237 1238 if (db->db_blkid != DMU_BONUS_BLKID) { 1239 /* 1240 * Update the accounting. 1241 * Note: we delay "free accounting" until after we drop 1242 * the db_mtx. This keeps us from grabbing other locks 1243 * (and possibly deadlocking) in bp_get_dsize() while 1244 * also holding the db_mtx. 1245 */ 1246 dnode_willuse_space(dn, db->db.db_size, tx); 1247 do_free_accounting = dbuf_block_freeable(db); 1248 } 1249 1250 /* 1251 * If this buffer is dirty in an old transaction group we need 1252 * to make a copy of it so that the changes we make in this 1253 * transaction group won't leak out when we sync the older txg. 1254 */ 1255 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP); 1256 if (db->db_level == 0) { 1257 void *data_old = db->db_buf; 1258 1259 if (db->db_state != DB_NOFILL) { 1260 if (db->db_blkid == DMU_BONUS_BLKID) { 1261 dbuf_fix_old_data(db, tx->tx_txg); 1262 data_old = db->db.db_data; 1263 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) { 1264 /* 1265 * Release the data buffer from the cache so 1266 * that we can modify it without impacting 1267 * possible other users of this cached data 1268 * block. Note that indirect blocks and 1269 * private objects are not released until the 1270 * syncing state (since they are only modified 1271 * then). 1272 */ 1273 arc_release(db->db_buf, db); 1274 dbuf_fix_old_data(db, tx->tx_txg); 1275 data_old = db->db_buf; 1276 } 1277 ASSERT(data_old != NULL); 1278 } 1279 dr->dt.dl.dr_data = data_old; 1280 } else { 1281 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL); 1282 list_create(&dr->dt.di.dr_children, 1283 sizeof (dbuf_dirty_record_t), 1284 offsetof(dbuf_dirty_record_t, dr_dirty_node)); 1285 } 1286 if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL) 1287 dr->dr_accounted = db->db.db_size; 1288 dr->dr_dbuf = db; 1289 dr->dr_txg = tx->tx_txg; 1290 dr->dr_next = *drp; 1291 *drp = dr; 1292 1293 /* 1294 * We could have been freed_in_flight between the dbuf_noread 1295 * and dbuf_dirty. We win, as though the dbuf_noread() had 1296 * happened after the free. 1297 */ 1298 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1299 db->db_blkid != DMU_SPILL_BLKID) { 1300 mutex_enter(&dn->dn_mtx); 1301 if (dn->dn_free_ranges[txgoff] != NULL) { 1302 range_tree_clear(dn->dn_free_ranges[txgoff], 1303 db->db_blkid, 1); 1304 } 1305 mutex_exit(&dn->dn_mtx); 1306 db->db_freed_in_flight = FALSE; 1307 } 1308 1309 /* 1310 * This buffer is now part of this txg 1311 */ 1312 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg); 1313 db->db_dirtycnt += 1; 1314 ASSERT3U(db->db_dirtycnt, <=, 3); 1315 1316 mutex_exit(&db->db_mtx); 1317 1318 if (db->db_blkid == DMU_BONUS_BLKID || 1319 db->db_blkid == DMU_SPILL_BLKID) { 1320 mutex_enter(&dn->dn_mtx); 1321 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1322 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1323 mutex_exit(&dn->dn_mtx); 1324 dnode_setdirty(dn, tx); 1325 DB_DNODE_EXIT(db); 1326 return (dr); 1327 } else if (do_free_accounting) { 1328 blkptr_t *bp = db->db_blkptr; 1329 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ? 1330 bp_get_dsize(os->os_spa, bp) : db->db.db_size; 1331 /* 1332 * This is only a guess -- if the dbuf is dirty 1333 * in a previous txg, we don't know how much 1334 * space it will use on disk yet. We should 1335 * really have the struct_rwlock to access 1336 * db_blkptr, but since this is just a guess, 1337 * it's OK if we get an odd answer. 1338 */ 1339 ddt_prefetch(os->os_spa, bp); 1340 dnode_willuse_space(dn, -willfree, tx); 1341 } 1342 1343 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 1344 rw_enter(&dn->dn_struct_rwlock, RW_READER); 1345 drop_struct_lock = TRUE; 1346 } 1347 1348 if (db->db_level == 0) { 1349 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock); 1350 ASSERT(dn->dn_maxblkid >= db->db_blkid); 1351 } 1352 1353 if (db->db_level+1 < dn->dn_nlevels) { 1354 dmu_buf_impl_t *parent = db->db_parent; 1355 dbuf_dirty_record_t *di; 1356 int parent_held = FALSE; 1357 1358 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) { 1359 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1360 1361 parent = dbuf_hold_level(dn, db->db_level+1, 1362 db->db_blkid >> epbs, FTAG); 1363 ASSERT(parent != NULL); 1364 parent_held = TRUE; 1365 } 1366 if (drop_struct_lock) 1367 rw_exit(&dn->dn_struct_rwlock); 1368 ASSERT3U(db->db_level+1, ==, parent->db_level); 1369 di = dbuf_dirty(parent, tx); 1370 if (parent_held) 1371 dbuf_rele(parent, FTAG); 1372 1373 mutex_enter(&db->db_mtx); 1374 /* 1375 * Since we've dropped the mutex, it's possible that 1376 * dbuf_undirty() might have changed this out from under us. 1377 */ 1378 if (db->db_last_dirty == dr || 1379 dn->dn_object == DMU_META_DNODE_OBJECT) { 1380 mutex_enter(&di->dt.di.dr_mtx); 1381 ASSERT3U(di->dr_txg, ==, tx->tx_txg); 1382 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1383 list_insert_tail(&di->dt.di.dr_children, dr); 1384 mutex_exit(&di->dt.di.dr_mtx); 1385 dr->dr_parent = di; 1386 } 1387 mutex_exit(&db->db_mtx); 1388 } else { 1389 ASSERT(db->db_level+1 == dn->dn_nlevels); 1390 ASSERT(db->db_blkid < dn->dn_nblkptr); 1391 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf); 1392 mutex_enter(&dn->dn_mtx); 1393 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1394 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1395 mutex_exit(&dn->dn_mtx); 1396 if (drop_struct_lock) 1397 rw_exit(&dn->dn_struct_rwlock); 1398 } 1399 1400 dnode_setdirty(dn, tx); 1401 DB_DNODE_EXIT(db); 1402 return (dr); 1403 } 1404 1405 /* 1406 * Undirty a buffer in the transaction group referenced by the given 1407 * transaction. Return whether this evicted the dbuf. 1408 */ 1409 static boolean_t 1410 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1411 { 1412 dnode_t *dn; 1413 uint64_t txg = tx->tx_txg; 1414 dbuf_dirty_record_t *dr, **drp; 1415 1416 ASSERT(txg != 0); 1417 1418 /* 1419 * Due to our use of dn_nlevels below, this can only be called 1420 * in open context, unless we are operating on the MOS. 1421 * From syncing context, dn_nlevels may be different from the 1422 * dn_nlevels used when dbuf was dirtied. 1423 */ 1424 ASSERT(db->db_objset == 1425 dmu_objset_pool(db->db_objset)->dp_meta_objset || 1426 txg != spa_syncing_txg(dmu_objset_spa(db->db_objset))); 1427 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1428 ASSERT0(db->db_level); 1429 ASSERT(MUTEX_HELD(&db->db_mtx)); 1430 1431 /* 1432 * If this buffer is not dirty, we're done. 1433 */ 1434 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next) 1435 if (dr->dr_txg <= txg) 1436 break; 1437 if (dr == NULL || dr->dr_txg < txg) 1438 return (B_FALSE); 1439 ASSERT(dr->dr_txg == txg); 1440 ASSERT(dr->dr_dbuf == db); 1441 1442 DB_DNODE_ENTER(db); 1443 dn = DB_DNODE(db); 1444 1445 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1446 1447 ASSERT(db->db.db_size != 0); 1448 1449 dsl_pool_undirty_space(dmu_objset_pool(dn->dn_objset), 1450 dr->dr_accounted, txg); 1451 1452 *drp = dr->dr_next; 1453 1454 /* 1455 * Note that there are three places in dbuf_dirty() 1456 * where this dirty record may be put on a list. 1457 * Make sure to do a list_remove corresponding to 1458 * every one of those list_insert calls. 1459 */ 1460 if (dr->dr_parent) { 1461 mutex_enter(&dr->dr_parent->dt.di.dr_mtx); 1462 list_remove(&dr->dr_parent->dt.di.dr_children, dr); 1463 mutex_exit(&dr->dr_parent->dt.di.dr_mtx); 1464 } else if (db->db_blkid == DMU_SPILL_BLKID || 1465 db->db_level + 1 == dn->dn_nlevels) { 1466 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf); 1467 mutex_enter(&dn->dn_mtx); 1468 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr); 1469 mutex_exit(&dn->dn_mtx); 1470 } 1471 DB_DNODE_EXIT(db); 1472 1473 if (db->db_state != DB_NOFILL) { 1474 dbuf_unoverride(dr); 1475 1476 ASSERT(db->db_buf != NULL); 1477 ASSERT(dr->dt.dl.dr_data != NULL); 1478 if (dr->dt.dl.dr_data != db->db_buf) 1479 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db)); 1480 } 1481 1482 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 1483 1484 ASSERT(db->db_dirtycnt > 0); 1485 db->db_dirtycnt -= 1; 1486 1487 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) { 1488 arc_buf_t *buf = db->db_buf; 1489 1490 ASSERT(db->db_state == DB_NOFILL || arc_released(buf)); 1491 dbuf_clear_data(db); 1492 VERIFY(arc_buf_remove_ref(buf, db)); 1493 dbuf_evict(db); 1494 return (B_TRUE); 1495 } 1496 1497 return (B_FALSE); 1498 } 1499 1500 void 1501 dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx) 1502 { 1503 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1504 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH; 1505 1506 ASSERT(tx->tx_txg != 0); 1507 ASSERT(!refcount_is_zero(&db->db_holds)); 1508 1509 DB_DNODE_ENTER(db); 1510 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock)) 1511 rf |= DB_RF_HAVESTRUCT; 1512 DB_DNODE_EXIT(db); 1513 (void) dbuf_read(db, NULL, rf); 1514 (void) dbuf_dirty(db, tx); 1515 } 1516 1517 void 1518 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1519 { 1520 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1521 1522 db->db_state = DB_NOFILL; 1523 1524 dmu_buf_will_fill(db_fake, tx); 1525 } 1526 1527 void 1528 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1529 { 1530 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1531 1532 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1533 ASSERT(tx->tx_txg != 0); 1534 ASSERT(db->db_level == 0); 1535 ASSERT(!refcount_is_zero(&db->db_holds)); 1536 1537 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT || 1538 dmu_tx_private_ok(tx)); 1539 1540 dbuf_noread(db); 1541 (void) dbuf_dirty(db, tx); 1542 } 1543 1544 #pragma weak dmu_buf_fill_done = dbuf_fill_done 1545 /* ARGSUSED */ 1546 void 1547 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx) 1548 { 1549 mutex_enter(&db->db_mtx); 1550 DBUF_VERIFY(db); 1551 1552 if (db->db_state == DB_FILL) { 1553 if (db->db_level == 0 && db->db_freed_in_flight) { 1554 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1555 /* we were freed while filling */ 1556 /* XXX dbuf_undirty? */ 1557 bzero(db->db.db_data, db->db.db_size); 1558 db->db_freed_in_flight = FALSE; 1559 } 1560 db->db_state = DB_CACHED; 1561 cv_broadcast(&db->db_changed); 1562 } 1563 mutex_exit(&db->db_mtx); 1564 } 1565 1566 void 1567 dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data, 1568 bp_embedded_type_t etype, enum zio_compress comp, 1569 int uncompressed_size, int compressed_size, int byteorder, 1570 dmu_tx_t *tx) 1571 { 1572 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 1573 struct dirty_leaf *dl; 1574 dmu_object_type_t type; 1575 1576 if (etype == BP_EMBEDDED_TYPE_DATA) { 1577 ASSERT(spa_feature_is_active(dmu_objset_spa(db->db_objset), 1578 SPA_FEATURE_EMBEDDED_DATA)); 1579 } 1580 1581 DB_DNODE_ENTER(db); 1582 type = DB_DNODE(db)->dn_type; 1583 DB_DNODE_EXIT(db); 1584 1585 ASSERT0(db->db_level); 1586 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1587 1588 dmu_buf_will_not_fill(dbuf, tx); 1589 1590 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 1591 dl = &db->db_last_dirty->dt.dl; 1592 encode_embedded_bp_compressed(&dl->dr_overridden_by, 1593 data, comp, uncompressed_size, compressed_size); 1594 BPE_SET_ETYPE(&dl->dr_overridden_by, etype); 1595 BP_SET_TYPE(&dl->dr_overridden_by, type); 1596 BP_SET_LEVEL(&dl->dr_overridden_by, 0); 1597 BP_SET_BYTEORDER(&dl->dr_overridden_by, byteorder); 1598 1599 dl->dr_override_state = DR_OVERRIDDEN; 1600 dl->dr_overridden_by.blk_birth = db->db_last_dirty->dr_txg; 1601 } 1602 1603 /* 1604 * Directly assign a provided arc buf to a given dbuf if it's not referenced 1605 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf. 1606 */ 1607 void 1608 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx) 1609 { 1610 ASSERT(!refcount_is_zero(&db->db_holds)); 1611 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1612 ASSERT(db->db_level == 0); 1613 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA); 1614 ASSERT(buf != NULL); 1615 ASSERT(arc_buf_size(buf) == db->db.db_size); 1616 ASSERT(tx->tx_txg != 0); 1617 1618 arc_return_buf(buf, db); 1619 ASSERT(arc_released(buf)); 1620 1621 mutex_enter(&db->db_mtx); 1622 1623 while (db->db_state == DB_READ || db->db_state == DB_FILL) 1624 cv_wait(&db->db_changed, &db->db_mtx); 1625 1626 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED); 1627 1628 if (db->db_state == DB_CACHED && 1629 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) { 1630 mutex_exit(&db->db_mtx); 1631 (void) dbuf_dirty(db, tx); 1632 bcopy(buf->b_data, db->db.db_data, db->db.db_size); 1633 VERIFY(arc_buf_remove_ref(buf, db)); 1634 xuio_stat_wbuf_copied(); 1635 return; 1636 } 1637 1638 xuio_stat_wbuf_nocopy(); 1639 if (db->db_state == DB_CACHED) { 1640 dbuf_dirty_record_t *dr = db->db_last_dirty; 1641 1642 ASSERT(db->db_buf != NULL); 1643 if (dr != NULL && dr->dr_txg == tx->tx_txg) { 1644 ASSERT(dr->dt.dl.dr_data == db->db_buf); 1645 if (!arc_released(db->db_buf)) { 1646 ASSERT(dr->dt.dl.dr_override_state == 1647 DR_OVERRIDDEN); 1648 arc_release(db->db_buf, db); 1649 } 1650 dr->dt.dl.dr_data = buf; 1651 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1652 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) { 1653 arc_release(db->db_buf, db); 1654 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1655 } 1656 db->db_buf = NULL; 1657 } 1658 ASSERT(db->db_buf == NULL); 1659 dbuf_set_data(db, buf); 1660 db->db_state = DB_FILL; 1661 mutex_exit(&db->db_mtx); 1662 (void) dbuf_dirty(db, tx); 1663 dmu_buf_fill_done(&db->db, tx); 1664 } 1665 1666 /* 1667 * "Clear" the contents of this dbuf. This will mark the dbuf 1668 * EVICTING and clear *most* of its references. Unfortunately, 1669 * when we are not holding the dn_dbufs_mtx, we can't clear the 1670 * entry in the dn_dbufs list. We have to wait until dbuf_destroy() 1671 * in this case. For callers from the DMU we will usually see: 1672 * dbuf_clear()->arc_clear_callback()->dbuf_do_evict()->dbuf_destroy() 1673 * For the arc callback, we will usually see: 1674 * dbuf_do_evict()->dbuf_clear();dbuf_destroy() 1675 * Sometimes, though, we will get a mix of these two: 1676 * DMU: dbuf_clear()->arc_clear_callback() 1677 * ARC: dbuf_do_evict()->dbuf_destroy() 1678 * 1679 * This routine will dissociate the dbuf from the arc, by calling 1680 * arc_clear_callback(), but will not evict the data from the ARC. 1681 */ 1682 void 1683 dbuf_clear(dmu_buf_impl_t *db) 1684 { 1685 dnode_t *dn; 1686 dmu_buf_impl_t *parent = db->db_parent; 1687 dmu_buf_impl_t *dndb; 1688 boolean_t dbuf_gone = B_FALSE; 1689 1690 ASSERT(MUTEX_HELD(&db->db_mtx)); 1691 ASSERT(refcount_is_zero(&db->db_holds)); 1692 1693 dbuf_evict_user(db); 1694 1695 if (db->db_state == DB_CACHED) { 1696 ASSERT(db->db.db_data != NULL); 1697 if (db->db_blkid == DMU_BONUS_BLKID) { 1698 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN); 1699 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 1700 } 1701 db->db.db_data = NULL; 1702 db->db_state = DB_UNCACHED; 1703 } 1704 1705 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL); 1706 ASSERT(db->db_data_pending == NULL); 1707 1708 db->db_state = DB_EVICTING; 1709 db->db_blkptr = NULL; 1710 1711 DB_DNODE_ENTER(db); 1712 dn = DB_DNODE(db); 1713 dndb = dn->dn_dbuf; 1714 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) { 1715 avl_remove(&dn->dn_dbufs, db); 1716 atomic_dec_32(&dn->dn_dbufs_count); 1717 membar_producer(); 1718 DB_DNODE_EXIT(db); 1719 /* 1720 * Decrementing the dbuf count means that the hold corresponding 1721 * to the removed dbuf is no longer discounted in dnode_move(), 1722 * so the dnode cannot be moved until after we release the hold. 1723 * The membar_producer() ensures visibility of the decremented 1724 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually 1725 * release any lock. 1726 */ 1727 dnode_rele(dn, db); 1728 db->db_dnode_handle = NULL; 1729 } else { 1730 DB_DNODE_EXIT(db); 1731 } 1732 1733 if (db->db_buf) 1734 dbuf_gone = arc_clear_callback(db->db_buf); 1735 1736 if (!dbuf_gone) 1737 mutex_exit(&db->db_mtx); 1738 1739 /* 1740 * If this dbuf is referenced from an indirect dbuf, 1741 * decrement the ref count on the indirect dbuf. 1742 */ 1743 if (parent && parent != dndb) 1744 dbuf_rele(parent, db); 1745 } 1746 1747 /* 1748 * Note: While bpp will always be updated if the function returns success, 1749 * parentp will not be updated if the dnode does not have dn_dbuf filled in; 1750 * this happens when the dnode is the meta-dnode, or a userused or groupused 1751 * object. 1752 */ 1753 static int 1754 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, 1755 dmu_buf_impl_t **parentp, blkptr_t **bpp) 1756 { 1757 int nlevels, epbs; 1758 1759 *parentp = NULL; 1760 *bpp = NULL; 1761 1762 ASSERT(blkid != DMU_BONUS_BLKID); 1763 1764 if (blkid == DMU_SPILL_BLKID) { 1765 mutex_enter(&dn->dn_mtx); 1766 if (dn->dn_have_spill && 1767 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) 1768 *bpp = &dn->dn_phys->dn_spill; 1769 else 1770 *bpp = NULL; 1771 dbuf_add_ref(dn->dn_dbuf, NULL); 1772 *parentp = dn->dn_dbuf; 1773 mutex_exit(&dn->dn_mtx); 1774 return (0); 1775 } 1776 1777 if (dn->dn_phys->dn_nlevels == 0) 1778 nlevels = 1; 1779 else 1780 nlevels = dn->dn_phys->dn_nlevels; 1781 1782 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1783 1784 ASSERT3U(level * epbs, <, 64); 1785 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1786 if (level >= nlevels || 1787 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) { 1788 /* the buffer has no parent yet */ 1789 return (SET_ERROR(ENOENT)); 1790 } else if (level < nlevels-1) { 1791 /* this block is referenced from an indirect block */ 1792 int err = dbuf_hold_impl(dn, level+1, 1793 blkid >> epbs, fail_sparse, FALSE, NULL, parentp); 1794 if (err) 1795 return (err); 1796 err = dbuf_read(*parentp, NULL, 1797 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL)); 1798 if (err) { 1799 dbuf_rele(*parentp, NULL); 1800 *parentp = NULL; 1801 return (err); 1802 } 1803 *bpp = ((blkptr_t *)(*parentp)->db.db_data) + 1804 (blkid & ((1ULL << epbs) - 1)); 1805 return (0); 1806 } else { 1807 /* the block is referenced from the dnode */ 1808 ASSERT3U(level, ==, nlevels-1); 1809 ASSERT(dn->dn_phys->dn_nblkptr == 0 || 1810 blkid < dn->dn_phys->dn_nblkptr); 1811 if (dn->dn_dbuf) { 1812 dbuf_add_ref(dn->dn_dbuf, NULL); 1813 *parentp = dn->dn_dbuf; 1814 } 1815 *bpp = &dn->dn_phys->dn_blkptr[blkid]; 1816 return (0); 1817 } 1818 } 1819 1820 static dmu_buf_impl_t * 1821 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid, 1822 dmu_buf_impl_t *parent, blkptr_t *blkptr) 1823 { 1824 objset_t *os = dn->dn_objset; 1825 dmu_buf_impl_t *db, *odb; 1826 1827 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1828 ASSERT(dn->dn_type != DMU_OT_NONE); 1829 1830 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP); 1831 1832 db->db_objset = os; 1833 db->db.db_object = dn->dn_object; 1834 db->db_level = level; 1835 db->db_blkid = blkid; 1836 db->db_last_dirty = NULL; 1837 db->db_dirtycnt = 0; 1838 db->db_dnode_handle = dn->dn_handle; 1839 db->db_parent = parent; 1840 db->db_blkptr = blkptr; 1841 1842 db->db_user = NULL; 1843 db->db_user_immediate_evict = FALSE; 1844 db->db_freed_in_flight = FALSE; 1845 db->db_pending_evict = FALSE; 1846 1847 if (blkid == DMU_BONUS_BLKID) { 1848 ASSERT3P(parent, ==, dn->dn_dbuf); 1849 db->db.db_size = DN_MAX_BONUSLEN - 1850 (dn->dn_nblkptr-1) * sizeof (blkptr_t); 1851 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 1852 db->db.db_offset = DMU_BONUS_BLKID; 1853 db->db_state = DB_UNCACHED; 1854 /* the bonus dbuf is not placed in the hash table */ 1855 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1856 return (db); 1857 } else if (blkid == DMU_SPILL_BLKID) { 1858 db->db.db_size = (blkptr != NULL) ? 1859 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE; 1860 db->db.db_offset = 0; 1861 } else { 1862 int blocksize = 1863 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz; 1864 db->db.db_size = blocksize; 1865 db->db.db_offset = db->db_blkid * blocksize; 1866 } 1867 1868 /* 1869 * Hold the dn_dbufs_mtx while we get the new dbuf 1870 * in the hash table *and* added to the dbufs list. 1871 * This prevents a possible deadlock with someone 1872 * trying to look up this dbuf before its added to the 1873 * dn_dbufs list. 1874 */ 1875 mutex_enter(&dn->dn_dbufs_mtx); 1876 db->db_state = DB_EVICTING; 1877 if ((odb = dbuf_hash_insert(db)) != NULL) { 1878 /* someone else inserted it first */ 1879 kmem_cache_free(dbuf_cache, db); 1880 mutex_exit(&dn->dn_dbufs_mtx); 1881 return (odb); 1882 } 1883 avl_add(&dn->dn_dbufs, db); 1884 if (db->db_level == 0 && db->db_blkid >= 1885 dn->dn_unlisted_l0_blkid) 1886 dn->dn_unlisted_l0_blkid = db->db_blkid + 1; 1887 db->db_state = DB_UNCACHED; 1888 mutex_exit(&dn->dn_dbufs_mtx); 1889 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1890 1891 if (parent && parent != dn->dn_dbuf) 1892 dbuf_add_ref(parent, db); 1893 1894 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1895 refcount_count(&dn->dn_holds) > 0); 1896 (void) refcount_add(&dn->dn_holds, db); 1897 atomic_inc_32(&dn->dn_dbufs_count); 1898 1899 dprintf_dbuf(db, "db=%p\n", db); 1900 1901 return (db); 1902 } 1903 1904 static int 1905 dbuf_do_evict(void *private) 1906 { 1907 dmu_buf_impl_t *db = private; 1908 1909 if (!MUTEX_HELD(&db->db_mtx)) 1910 mutex_enter(&db->db_mtx); 1911 1912 ASSERT(refcount_is_zero(&db->db_holds)); 1913 1914 if (db->db_state != DB_EVICTING) { 1915 ASSERT(db->db_state == DB_CACHED); 1916 DBUF_VERIFY(db); 1917 db->db_buf = NULL; 1918 dbuf_evict(db); 1919 } else { 1920 mutex_exit(&db->db_mtx); 1921 dbuf_destroy(db); 1922 } 1923 return (0); 1924 } 1925 1926 static void 1927 dbuf_destroy(dmu_buf_impl_t *db) 1928 { 1929 ASSERT(refcount_is_zero(&db->db_holds)); 1930 1931 if (db->db_blkid != DMU_BONUS_BLKID) { 1932 /* 1933 * If this dbuf is still on the dn_dbufs list, 1934 * remove it from that list. 1935 */ 1936 if (db->db_dnode_handle != NULL) { 1937 dnode_t *dn; 1938 1939 DB_DNODE_ENTER(db); 1940 dn = DB_DNODE(db); 1941 mutex_enter(&dn->dn_dbufs_mtx); 1942 avl_remove(&dn->dn_dbufs, db); 1943 atomic_dec_32(&dn->dn_dbufs_count); 1944 mutex_exit(&dn->dn_dbufs_mtx); 1945 DB_DNODE_EXIT(db); 1946 /* 1947 * Decrementing the dbuf count means that the hold 1948 * corresponding to the removed dbuf is no longer 1949 * discounted in dnode_move(), so the dnode cannot be 1950 * moved until after we release the hold. 1951 */ 1952 dnode_rele(dn, db); 1953 db->db_dnode_handle = NULL; 1954 } 1955 dbuf_hash_remove(db); 1956 } 1957 db->db_parent = NULL; 1958 db->db_buf = NULL; 1959 1960 ASSERT(db->db.db_data == NULL); 1961 ASSERT(db->db_hash_next == NULL); 1962 ASSERT(db->db_blkptr == NULL); 1963 ASSERT(db->db_data_pending == NULL); 1964 1965 kmem_cache_free(dbuf_cache, db); 1966 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1967 } 1968 1969 typedef struct dbuf_prefetch_arg { 1970 spa_t *dpa_spa; /* The spa to issue the prefetch in. */ 1971 zbookmark_phys_t dpa_zb; /* The target block to prefetch. */ 1972 int dpa_epbs; /* Entries (blkptr_t's) Per Block Shift. */ 1973 int dpa_curlevel; /* The current level that we're reading */ 1974 zio_priority_t dpa_prio; /* The priority I/Os should be issued at. */ 1975 zio_t *dpa_zio; /* The parent zio_t for all prefetches. */ 1976 arc_flags_t dpa_aflags; /* Flags to pass to the final prefetch. */ 1977 } dbuf_prefetch_arg_t; 1978 1979 /* 1980 * Actually issue the prefetch read for the block given. 1981 */ 1982 static void 1983 dbuf_issue_final_prefetch(dbuf_prefetch_arg_t *dpa, blkptr_t *bp) 1984 { 1985 if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) 1986 return; 1987 1988 arc_flags_t aflags = 1989 dpa->dpa_aflags | ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH; 1990 1991 ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); 1992 ASSERT3U(dpa->dpa_curlevel, ==, dpa->dpa_zb.zb_level); 1993 ASSERT(dpa->dpa_zio != NULL); 1994 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, bp, NULL, NULL, 1995 dpa->dpa_prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 1996 &aflags, &dpa->dpa_zb); 1997 } 1998 1999 /* 2000 * Called when an indirect block above our prefetch target is read in. This 2001 * will either read in the next indirect block down the tree or issue the actual 2002 * prefetch if the next block down is our target. 2003 */ 2004 static void 2005 dbuf_prefetch_indirect_done(zio_t *zio, arc_buf_t *abuf, void *private) 2006 { 2007 dbuf_prefetch_arg_t *dpa = private; 2008 2009 ASSERT3S(dpa->dpa_zb.zb_level, <, dpa->dpa_curlevel); 2010 ASSERT3S(dpa->dpa_curlevel, >, 0); 2011 if (zio != NULL) { 2012 ASSERT3S(BP_GET_LEVEL(zio->io_bp), ==, dpa->dpa_curlevel); 2013 ASSERT3U(BP_GET_LSIZE(zio->io_bp), ==, zio->io_size); 2014 ASSERT3P(zio->io_spa, ==, dpa->dpa_spa); 2015 } 2016 2017 dpa->dpa_curlevel--; 2018 2019 uint64_t nextblkid = dpa->dpa_zb.zb_blkid >> 2020 (dpa->dpa_epbs * (dpa->dpa_curlevel - dpa->dpa_zb.zb_level)); 2021 blkptr_t *bp = ((blkptr_t *)abuf->b_data) + 2022 P2PHASE(nextblkid, 1ULL << dpa->dpa_epbs); 2023 if (BP_IS_HOLE(bp) || (zio != NULL && zio->io_error != 0)) { 2024 kmem_free(dpa, sizeof (*dpa)); 2025 } else if (dpa->dpa_curlevel == dpa->dpa_zb.zb_level) { 2026 ASSERT3U(nextblkid, ==, dpa->dpa_zb.zb_blkid); 2027 dbuf_issue_final_prefetch(dpa, bp); 2028 kmem_free(dpa, sizeof (*dpa)); 2029 } else { 2030 arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; 2031 zbookmark_phys_t zb; 2032 2033 ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); 2034 2035 SET_BOOKMARK(&zb, dpa->dpa_zb.zb_objset, 2036 dpa->dpa_zb.zb_object, dpa->dpa_curlevel, nextblkid); 2037 2038 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, 2039 bp, dbuf_prefetch_indirect_done, dpa, dpa->dpa_prio, 2040 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2041 &iter_aflags, &zb); 2042 } 2043 (void) arc_buf_remove_ref(abuf, private); 2044 } 2045 2046 /* 2047 * Issue prefetch reads for the given block on the given level. If the indirect 2048 * blocks above that block are not in memory, we will read them in 2049 * asynchronously. As a result, this call never blocks waiting for a read to 2050 * complete. 2051 */ 2052 void 2053 dbuf_prefetch(dnode_t *dn, int64_t level, uint64_t blkid, zio_priority_t prio, 2054 arc_flags_t aflags) 2055 { 2056 blkptr_t bp; 2057 int epbs, nlevels, curlevel; 2058 uint64_t curblkid; 2059 2060 ASSERT(blkid != DMU_BONUS_BLKID); 2061 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 2062 2063 if (dnode_block_freed(dn, blkid)) 2064 return; 2065 2066 /* 2067 * This dnode hasn't been written to disk yet, so there's nothing to 2068 * prefetch. 2069 */ 2070 nlevels = dn->dn_phys->dn_nlevels; 2071 if (level >= nlevels || dn->dn_phys->dn_nblkptr == 0) 2072 return; 2073 2074 epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2075 if (dn->dn_phys->dn_maxblkid < blkid << (epbs * level)) 2076 return; 2077 2078 dmu_buf_impl_t *db = dbuf_find(dn->dn_objset, dn->dn_object, 2079 level, blkid); 2080 if (db != NULL) { 2081 mutex_exit(&db->db_mtx); 2082 /* 2083 * This dbuf already exists. It is either CACHED, or 2084 * (we assume) about to be read or filled. 2085 */ 2086 return; 2087 } 2088 2089 /* 2090 * Find the closest ancestor (indirect block) of the target block 2091 * that is present in the cache. In this indirect block, we will 2092 * find the bp that is at curlevel, curblkid. 2093 */ 2094 curlevel = level; 2095 curblkid = blkid; 2096 while (curlevel < nlevels - 1) { 2097 int parent_level = curlevel + 1; 2098 uint64_t parent_blkid = curblkid >> epbs; 2099 dmu_buf_impl_t *db; 2100 2101 if (dbuf_hold_impl(dn, parent_level, parent_blkid, 2102 FALSE, TRUE, FTAG, &db) == 0) { 2103 blkptr_t *bpp = db->db_buf->b_data; 2104 bp = bpp[P2PHASE(curblkid, 1 << epbs)]; 2105 dbuf_rele(db, FTAG); 2106 break; 2107 } 2108 2109 curlevel = parent_level; 2110 curblkid = parent_blkid; 2111 } 2112 2113 if (curlevel == nlevels - 1) { 2114 /* No cached indirect blocks found. */ 2115 ASSERT3U(curblkid, <, dn->dn_phys->dn_nblkptr); 2116 bp = dn->dn_phys->dn_blkptr[curblkid]; 2117 } 2118 if (BP_IS_HOLE(&bp)) 2119 return; 2120 2121 ASSERT3U(curlevel, ==, BP_GET_LEVEL(&bp)); 2122 2123 zio_t *pio = zio_root(dmu_objset_spa(dn->dn_objset), NULL, NULL, 2124 ZIO_FLAG_CANFAIL); 2125 2126 dbuf_prefetch_arg_t *dpa = kmem_zalloc(sizeof (*dpa), KM_SLEEP); 2127 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; 2128 SET_BOOKMARK(&dpa->dpa_zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, 2129 dn->dn_object, level, blkid); 2130 dpa->dpa_curlevel = curlevel; 2131 dpa->dpa_prio = prio; 2132 dpa->dpa_aflags = aflags; 2133 dpa->dpa_spa = dn->dn_objset->os_spa; 2134 dpa->dpa_epbs = epbs; 2135 dpa->dpa_zio = pio; 2136 2137 /* 2138 * If we have the indirect just above us, no need to do the asynchronous 2139 * prefetch chain; we'll just run the last step ourselves. If we're at 2140 * a higher level, though, we want to issue the prefetches for all the 2141 * indirect blocks asynchronously, so we can go on with whatever we were 2142 * doing. 2143 */ 2144 if (curlevel == level) { 2145 ASSERT3U(curblkid, ==, blkid); 2146 dbuf_issue_final_prefetch(dpa, &bp); 2147 kmem_free(dpa, sizeof (*dpa)); 2148 } else { 2149 arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; 2150 zbookmark_phys_t zb; 2151 2152 SET_BOOKMARK(&zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, 2153 dn->dn_object, curlevel, curblkid); 2154 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, 2155 &bp, dbuf_prefetch_indirect_done, dpa, prio, 2156 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2157 &iter_aflags, &zb); 2158 } 2159 /* 2160 * We use pio here instead of dpa_zio since it's possible that 2161 * dpa may have already been freed. 2162 */ 2163 zio_nowait(pio); 2164 } 2165 2166 /* 2167 * Returns with db_holds incremented, and db_mtx not held. 2168 * Note: dn_struct_rwlock must be held. 2169 */ 2170 int 2171 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, 2172 boolean_t fail_sparse, boolean_t fail_uncached, 2173 void *tag, dmu_buf_impl_t **dbp) 2174 { 2175 dmu_buf_impl_t *db, *parent = NULL; 2176 2177 ASSERT(blkid != DMU_BONUS_BLKID); 2178 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 2179 ASSERT3U(dn->dn_nlevels, >, level); 2180 2181 *dbp = NULL; 2182 top: 2183 /* dbuf_find() returns with db_mtx held */ 2184 db = dbuf_find(dn->dn_objset, dn->dn_object, level, blkid); 2185 2186 if (db == NULL) { 2187 blkptr_t *bp = NULL; 2188 int err; 2189 2190 if (fail_uncached) 2191 return (SET_ERROR(ENOENT)); 2192 2193 ASSERT3P(parent, ==, NULL); 2194 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp); 2195 if (fail_sparse) { 2196 if (err == 0 && bp && BP_IS_HOLE(bp)) 2197 err = SET_ERROR(ENOENT); 2198 if (err) { 2199 if (parent) 2200 dbuf_rele(parent, NULL); 2201 return (err); 2202 } 2203 } 2204 if (err && err != ENOENT) 2205 return (err); 2206 db = dbuf_create(dn, level, blkid, parent, bp); 2207 } 2208 2209 if (fail_uncached && db->db_state != DB_CACHED) { 2210 mutex_exit(&db->db_mtx); 2211 return (SET_ERROR(ENOENT)); 2212 } 2213 2214 if (db->db_buf && refcount_is_zero(&db->db_holds)) { 2215 arc_buf_add_ref(db->db_buf, db); 2216 if (db->db_buf->b_data == NULL) { 2217 dbuf_clear(db); 2218 if (parent) { 2219 dbuf_rele(parent, NULL); 2220 parent = NULL; 2221 } 2222 goto top; 2223 } 2224 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data); 2225 } 2226 2227 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf)); 2228 2229 /* 2230 * If this buffer is currently syncing out, and we are are 2231 * still referencing it from db_data, we need to make a copy 2232 * of it in case we decide we want to dirty it again in this txg. 2233 */ 2234 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 2235 dn->dn_object != DMU_META_DNODE_OBJECT && 2236 db->db_state == DB_CACHED && db->db_data_pending) { 2237 dbuf_dirty_record_t *dr = db->db_data_pending; 2238 2239 if (dr->dt.dl.dr_data == db->db_buf) { 2240 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2241 2242 dbuf_set_data(db, 2243 arc_buf_alloc(dn->dn_objset->os_spa, 2244 db->db.db_size, db, type)); 2245 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data, 2246 db->db.db_size); 2247 } 2248 } 2249 2250 (void) refcount_add(&db->db_holds, tag); 2251 DBUF_VERIFY(db); 2252 mutex_exit(&db->db_mtx); 2253 2254 /* NOTE: we can't rele the parent until after we drop the db_mtx */ 2255 if (parent) 2256 dbuf_rele(parent, NULL); 2257 2258 ASSERT3P(DB_DNODE(db), ==, dn); 2259 ASSERT3U(db->db_blkid, ==, blkid); 2260 ASSERT3U(db->db_level, ==, level); 2261 *dbp = db; 2262 2263 return (0); 2264 } 2265 2266 dmu_buf_impl_t * 2267 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag) 2268 { 2269 return (dbuf_hold_level(dn, 0, blkid, tag)); 2270 } 2271 2272 dmu_buf_impl_t * 2273 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag) 2274 { 2275 dmu_buf_impl_t *db; 2276 int err = dbuf_hold_impl(dn, level, blkid, FALSE, FALSE, tag, &db); 2277 return (err ? NULL : db); 2278 } 2279 2280 void 2281 dbuf_create_bonus(dnode_t *dn) 2282 { 2283 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 2284 2285 ASSERT(dn->dn_bonus == NULL); 2286 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL); 2287 } 2288 2289 int 2290 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx) 2291 { 2292 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2293 dnode_t *dn; 2294 2295 if (db->db_blkid != DMU_SPILL_BLKID) 2296 return (SET_ERROR(ENOTSUP)); 2297 if (blksz == 0) 2298 blksz = SPA_MINBLOCKSIZE; 2299 ASSERT3U(blksz, <=, spa_maxblocksize(dmu_objset_spa(db->db_objset))); 2300 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE); 2301 2302 DB_DNODE_ENTER(db); 2303 dn = DB_DNODE(db); 2304 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 2305 dbuf_new_size(db, blksz, tx); 2306 rw_exit(&dn->dn_struct_rwlock); 2307 DB_DNODE_EXIT(db); 2308 2309 return (0); 2310 } 2311 2312 void 2313 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx) 2314 { 2315 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx); 2316 } 2317 2318 #pragma weak dmu_buf_add_ref = dbuf_add_ref 2319 void 2320 dbuf_add_ref(dmu_buf_impl_t *db, void *tag) 2321 { 2322 int64_t holds = refcount_add(&db->db_holds, tag); 2323 ASSERT(holds > 1); 2324 } 2325 2326 #pragma weak dmu_buf_try_add_ref = dbuf_try_add_ref 2327 boolean_t 2328 dbuf_try_add_ref(dmu_buf_t *db_fake, objset_t *os, uint64_t obj, uint64_t blkid, 2329 void *tag) 2330 { 2331 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2332 dmu_buf_impl_t *found_db; 2333 boolean_t result = B_FALSE; 2334 2335 if (db->db_blkid == DMU_BONUS_BLKID) 2336 found_db = dbuf_find_bonus(os, obj); 2337 else 2338 found_db = dbuf_find(os, obj, 0, blkid); 2339 2340 if (found_db != NULL) { 2341 if (db == found_db && dbuf_refcount(db) > db->db_dirtycnt) { 2342 (void) refcount_add(&db->db_holds, tag); 2343 result = B_TRUE; 2344 } 2345 mutex_exit(&db->db_mtx); 2346 } 2347 return (result); 2348 } 2349 2350 /* 2351 * If you call dbuf_rele() you had better not be referencing the dnode handle 2352 * unless you have some other direct or indirect hold on the dnode. (An indirect 2353 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.) 2354 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the 2355 * dnode's parent dbuf evicting its dnode handles. 2356 */ 2357 void 2358 dbuf_rele(dmu_buf_impl_t *db, void *tag) 2359 { 2360 mutex_enter(&db->db_mtx); 2361 dbuf_rele_and_unlock(db, tag); 2362 } 2363 2364 void 2365 dmu_buf_rele(dmu_buf_t *db, void *tag) 2366 { 2367 dbuf_rele((dmu_buf_impl_t *)db, tag); 2368 } 2369 2370 /* 2371 * dbuf_rele() for an already-locked dbuf. This is necessary to allow 2372 * db_dirtycnt and db_holds to be updated atomically. 2373 */ 2374 void 2375 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) 2376 { 2377 int64_t holds; 2378 2379 ASSERT(MUTEX_HELD(&db->db_mtx)); 2380 DBUF_VERIFY(db); 2381 2382 /* 2383 * Remove the reference to the dbuf before removing its hold on the 2384 * dnode so we can guarantee in dnode_move() that a referenced bonus 2385 * buffer has a corresponding dnode hold. 2386 */ 2387 holds = refcount_remove(&db->db_holds, tag); 2388 ASSERT(holds >= 0); 2389 2390 /* 2391 * We can't freeze indirects if there is a possibility that they 2392 * may be modified in the current syncing context. 2393 */ 2394 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0)) 2395 arc_buf_freeze(db->db_buf); 2396 2397 if (holds == db->db_dirtycnt && 2398 db->db_level == 0 && db->db_user_immediate_evict) 2399 dbuf_evict_user(db); 2400 2401 if (holds == 0) { 2402 if (db->db_blkid == DMU_BONUS_BLKID) { 2403 dnode_t *dn; 2404 boolean_t evict_dbuf = db->db_pending_evict; 2405 2406 /* 2407 * If the dnode moves here, we cannot cross this 2408 * barrier until the move completes. 2409 */ 2410 DB_DNODE_ENTER(db); 2411 2412 dn = DB_DNODE(db); 2413 atomic_dec_32(&dn->dn_dbufs_count); 2414 2415 /* 2416 * Decrementing the dbuf count means that the bonus 2417 * buffer's dnode hold is no longer discounted in 2418 * dnode_move(). The dnode cannot move until after 2419 * the dnode_rele() below. 2420 */ 2421 DB_DNODE_EXIT(db); 2422 2423 /* 2424 * Do not reference db after its lock is dropped. 2425 * Another thread may evict it. 2426 */ 2427 mutex_exit(&db->db_mtx); 2428 2429 if (evict_dbuf) 2430 dnode_evict_bonus(dn); 2431 2432 dnode_rele(dn, db); 2433 } else if (db->db_buf == NULL) { 2434 /* 2435 * This is a special case: we never associated this 2436 * dbuf with any data allocated from the ARC. 2437 */ 2438 ASSERT(db->db_state == DB_UNCACHED || 2439 db->db_state == DB_NOFILL); 2440 dbuf_evict(db); 2441 } else if (arc_released(db->db_buf)) { 2442 arc_buf_t *buf = db->db_buf; 2443 /* 2444 * This dbuf has anonymous data associated with it. 2445 */ 2446 dbuf_clear_data(db); 2447 VERIFY(arc_buf_remove_ref(buf, db)); 2448 dbuf_evict(db); 2449 } else { 2450 VERIFY(!arc_buf_remove_ref(db->db_buf, db)); 2451 2452 /* 2453 * A dbuf will be eligible for eviction if either the 2454 * 'primarycache' property is set or a duplicate 2455 * copy of this buffer is already cached in the arc. 2456 * 2457 * In the case of the 'primarycache' a buffer 2458 * is considered for eviction if it matches the 2459 * criteria set in the property. 2460 * 2461 * To decide if our buffer is considered a 2462 * duplicate, we must call into the arc to determine 2463 * if multiple buffers are referencing the same 2464 * block on-disk. If so, then we simply evict 2465 * ourselves. 2466 */ 2467 if (!DBUF_IS_CACHEABLE(db)) { 2468 if (db->db_blkptr != NULL && 2469 !BP_IS_HOLE(db->db_blkptr) && 2470 !BP_IS_EMBEDDED(db->db_blkptr)) { 2471 spa_t *spa = 2472 dmu_objset_spa(db->db_objset); 2473 blkptr_t bp = *db->db_blkptr; 2474 dbuf_clear(db); 2475 arc_freed(spa, &bp); 2476 } else { 2477 dbuf_clear(db); 2478 } 2479 } else if (db->db_pending_evict || 2480 arc_buf_eviction_needed(db->db_buf)) { 2481 dbuf_clear(db); 2482 } else { 2483 mutex_exit(&db->db_mtx); 2484 } 2485 } 2486 } else { 2487 mutex_exit(&db->db_mtx); 2488 } 2489 } 2490 2491 #pragma weak dmu_buf_refcount = dbuf_refcount 2492 uint64_t 2493 dbuf_refcount(dmu_buf_impl_t *db) 2494 { 2495 return (refcount_count(&db->db_holds)); 2496 } 2497 2498 void * 2499 dmu_buf_replace_user(dmu_buf_t *db_fake, dmu_buf_user_t *old_user, 2500 dmu_buf_user_t *new_user) 2501 { 2502 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2503 2504 mutex_enter(&db->db_mtx); 2505 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2506 if (db->db_user == old_user) 2507 db->db_user = new_user; 2508 else 2509 old_user = db->db_user; 2510 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2511 mutex_exit(&db->db_mtx); 2512 2513 return (old_user); 2514 } 2515 2516 void * 2517 dmu_buf_set_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2518 { 2519 return (dmu_buf_replace_user(db_fake, NULL, user)); 2520 } 2521 2522 void * 2523 dmu_buf_set_user_ie(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2524 { 2525 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2526 2527 db->db_user_immediate_evict = TRUE; 2528 return (dmu_buf_set_user(db_fake, user)); 2529 } 2530 2531 void * 2532 dmu_buf_remove_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2533 { 2534 return (dmu_buf_replace_user(db_fake, user, NULL)); 2535 } 2536 2537 void * 2538 dmu_buf_get_user(dmu_buf_t *db_fake) 2539 { 2540 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2541 2542 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2543 return (db->db_user); 2544 } 2545 2546 void 2547 dmu_buf_user_evict_wait() 2548 { 2549 taskq_wait(dbu_evict_taskq); 2550 } 2551 2552 boolean_t 2553 dmu_buf_freeable(dmu_buf_t *dbuf) 2554 { 2555 boolean_t res = B_FALSE; 2556 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 2557 2558 if (db->db_blkptr) 2559 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset, 2560 db->db_blkptr, db->db_blkptr->blk_birth); 2561 2562 return (res); 2563 } 2564 2565 blkptr_t * 2566 dmu_buf_get_blkptr(dmu_buf_t *db) 2567 { 2568 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; 2569 return (dbi->db_blkptr); 2570 } 2571 2572 static void 2573 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db) 2574 { 2575 /* ASSERT(dmu_tx_is_syncing(tx) */ 2576 ASSERT(MUTEX_HELD(&db->db_mtx)); 2577 2578 if (db->db_blkptr != NULL) 2579 return; 2580 2581 if (db->db_blkid == DMU_SPILL_BLKID) { 2582 db->db_blkptr = &dn->dn_phys->dn_spill; 2583 BP_ZERO(db->db_blkptr); 2584 return; 2585 } 2586 if (db->db_level == dn->dn_phys->dn_nlevels-1) { 2587 /* 2588 * This buffer was allocated at a time when there was 2589 * no available blkptrs from the dnode, or it was 2590 * inappropriate to hook it in (i.e., nlevels mis-match). 2591 */ 2592 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr); 2593 ASSERT(db->db_parent == NULL); 2594 db->db_parent = dn->dn_dbuf; 2595 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid]; 2596 DBUF_VERIFY(db); 2597 } else { 2598 dmu_buf_impl_t *parent = db->db_parent; 2599 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2600 2601 ASSERT(dn->dn_phys->dn_nlevels > 1); 2602 if (parent == NULL) { 2603 mutex_exit(&db->db_mtx); 2604 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2605 parent = dbuf_hold_level(dn, db->db_level + 1, 2606 db->db_blkid >> epbs, db); 2607 rw_exit(&dn->dn_struct_rwlock); 2608 mutex_enter(&db->db_mtx); 2609 db->db_parent = parent; 2610 } 2611 db->db_blkptr = (blkptr_t *)parent->db.db_data + 2612 (db->db_blkid & ((1ULL << epbs) - 1)); 2613 DBUF_VERIFY(db); 2614 } 2615 } 2616 2617 static void 2618 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2619 { 2620 dmu_buf_impl_t *db = dr->dr_dbuf; 2621 dnode_t *dn; 2622 zio_t *zio; 2623 2624 ASSERT(dmu_tx_is_syncing(tx)); 2625 2626 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2627 2628 mutex_enter(&db->db_mtx); 2629 2630 ASSERT(db->db_level > 0); 2631 DBUF_VERIFY(db); 2632 2633 /* Read the block if it hasn't been read yet. */ 2634 if (db->db_buf == NULL) { 2635 mutex_exit(&db->db_mtx); 2636 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); 2637 mutex_enter(&db->db_mtx); 2638 } 2639 ASSERT3U(db->db_state, ==, DB_CACHED); 2640 ASSERT(db->db_buf != NULL); 2641 2642 DB_DNODE_ENTER(db); 2643 dn = DB_DNODE(db); 2644 /* Indirect block size must match what the dnode thinks it is. */ 2645 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2646 dbuf_check_blkptr(dn, db); 2647 DB_DNODE_EXIT(db); 2648 2649 /* Provide the pending dirty record to child dbufs */ 2650 db->db_data_pending = dr; 2651 2652 mutex_exit(&db->db_mtx); 2653 dbuf_write(dr, db->db_buf, tx); 2654 2655 zio = dr->dr_zio; 2656 mutex_enter(&dr->dt.di.dr_mtx); 2657 dbuf_sync_list(&dr->dt.di.dr_children, db->db_level - 1, tx); 2658 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2659 mutex_exit(&dr->dt.di.dr_mtx); 2660 zio_nowait(zio); 2661 } 2662 2663 static void 2664 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2665 { 2666 arc_buf_t **datap = &dr->dt.dl.dr_data; 2667 dmu_buf_impl_t *db = dr->dr_dbuf; 2668 dnode_t *dn; 2669 objset_t *os; 2670 uint64_t txg = tx->tx_txg; 2671 2672 ASSERT(dmu_tx_is_syncing(tx)); 2673 2674 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2675 2676 mutex_enter(&db->db_mtx); 2677 /* 2678 * To be synced, we must be dirtied. But we 2679 * might have been freed after the dirty. 2680 */ 2681 if (db->db_state == DB_UNCACHED) { 2682 /* This buffer has been freed since it was dirtied */ 2683 ASSERT(db->db.db_data == NULL); 2684 } else if (db->db_state == DB_FILL) { 2685 /* This buffer was freed and is now being re-filled */ 2686 ASSERT(db->db.db_data != dr->dt.dl.dr_data); 2687 } else { 2688 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); 2689 } 2690 DBUF_VERIFY(db); 2691 2692 DB_DNODE_ENTER(db); 2693 dn = DB_DNODE(db); 2694 2695 if (db->db_blkid == DMU_SPILL_BLKID) { 2696 mutex_enter(&dn->dn_mtx); 2697 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR; 2698 mutex_exit(&dn->dn_mtx); 2699 } 2700 2701 /* 2702 * If this is a bonus buffer, simply copy the bonus data into the 2703 * dnode. It will be written out when the dnode is synced (and it 2704 * will be synced, since it must have been dirty for dbuf_sync to 2705 * be called). 2706 */ 2707 if (db->db_blkid == DMU_BONUS_BLKID) { 2708 dbuf_dirty_record_t **drp; 2709 2710 ASSERT(*datap != NULL); 2711 ASSERT0(db->db_level); 2712 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN); 2713 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen); 2714 DB_DNODE_EXIT(db); 2715 2716 if (*datap != db->db.db_data) { 2717 zio_buf_free(*datap, DN_MAX_BONUSLEN); 2718 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 2719 } 2720 db->db_data_pending = NULL; 2721 drp = &db->db_last_dirty; 2722 while (*drp != dr) 2723 drp = &(*drp)->dr_next; 2724 ASSERT(dr->dr_next == NULL); 2725 ASSERT(dr->dr_dbuf == db); 2726 *drp = dr->dr_next; 2727 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2728 ASSERT(db->db_dirtycnt > 0); 2729 db->db_dirtycnt -= 1; 2730 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2731 return; 2732 } 2733 2734 os = dn->dn_objset; 2735 2736 /* 2737 * This function may have dropped the db_mtx lock allowing a dmu_sync 2738 * operation to sneak in. As a result, we need to ensure that we 2739 * don't check the dr_override_state until we have returned from 2740 * dbuf_check_blkptr. 2741 */ 2742 dbuf_check_blkptr(dn, db); 2743 2744 /* 2745 * If this buffer is in the middle of an immediate write, 2746 * wait for the synchronous IO to complete. 2747 */ 2748 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) { 2749 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); 2750 cv_wait(&db->db_changed, &db->db_mtx); 2751 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN); 2752 } 2753 2754 if (db->db_state != DB_NOFILL && 2755 dn->dn_object != DMU_META_DNODE_OBJECT && 2756 refcount_count(&db->db_holds) > 1 && 2757 dr->dt.dl.dr_override_state != DR_OVERRIDDEN && 2758 *datap == db->db_buf) { 2759 /* 2760 * If this buffer is currently "in use" (i.e., there 2761 * are active holds and db_data still references it), 2762 * then make a copy before we start the write so that 2763 * any modifications from the open txg will not leak 2764 * into this write. 2765 * 2766 * NOTE: this copy does not need to be made for 2767 * objects only modified in the syncing context (e.g. 2768 * DNONE_DNODE blocks). 2769 */ 2770 int blksz = arc_buf_size(*datap); 2771 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2772 *datap = arc_buf_alloc(os->os_spa, blksz, db, type); 2773 bcopy(db->db.db_data, (*datap)->b_data, blksz); 2774 } 2775 db->db_data_pending = dr; 2776 2777 mutex_exit(&db->db_mtx); 2778 2779 dbuf_write(dr, *datap, tx); 2780 2781 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2782 if (dn->dn_object == DMU_META_DNODE_OBJECT) { 2783 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr); 2784 DB_DNODE_EXIT(db); 2785 } else { 2786 /* 2787 * Although zio_nowait() does not "wait for an IO", it does 2788 * initiate the IO. If this is an empty write it seems plausible 2789 * that the IO could actually be completed before the nowait 2790 * returns. We need to DB_DNODE_EXIT() first in case 2791 * zio_nowait() invalidates the dbuf. 2792 */ 2793 DB_DNODE_EXIT(db); 2794 zio_nowait(dr->dr_zio); 2795 } 2796 } 2797 2798 void 2799 dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx) 2800 { 2801 dbuf_dirty_record_t *dr; 2802 2803 while (dr = list_head(list)) { 2804 if (dr->dr_zio != NULL) { 2805 /* 2806 * If we find an already initialized zio then we 2807 * are processing the meta-dnode, and we have finished. 2808 * The dbufs for all dnodes are put back on the list 2809 * during processing, so that we can zio_wait() 2810 * these IOs after initiating all child IOs. 2811 */ 2812 ASSERT3U(dr->dr_dbuf->db.db_object, ==, 2813 DMU_META_DNODE_OBJECT); 2814 break; 2815 } 2816 if (dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID && 2817 dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) { 2818 VERIFY3U(dr->dr_dbuf->db_level, ==, level); 2819 } 2820 list_remove(list, dr); 2821 if (dr->dr_dbuf->db_level > 0) 2822 dbuf_sync_indirect(dr, tx); 2823 else 2824 dbuf_sync_leaf(dr, tx); 2825 } 2826 } 2827 2828 /* ARGSUSED */ 2829 static void 2830 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb) 2831 { 2832 dmu_buf_impl_t *db = vdb; 2833 dnode_t *dn; 2834 blkptr_t *bp = zio->io_bp; 2835 blkptr_t *bp_orig = &zio->io_bp_orig; 2836 spa_t *spa = zio->io_spa; 2837 int64_t delta; 2838 uint64_t fill = 0; 2839 int i; 2840 2841 ASSERT3P(db->db_blkptr, ==, bp); 2842 2843 DB_DNODE_ENTER(db); 2844 dn = DB_DNODE(db); 2845 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig); 2846 dnode_diduse_space(dn, delta - zio->io_prev_space_delta); 2847 zio->io_prev_space_delta = delta; 2848 2849 if (bp->blk_birth != 0) { 2850 ASSERT((db->db_blkid != DMU_SPILL_BLKID && 2851 BP_GET_TYPE(bp) == dn->dn_type) || 2852 (db->db_blkid == DMU_SPILL_BLKID && 2853 BP_GET_TYPE(bp) == dn->dn_bonustype) || 2854 BP_IS_EMBEDDED(bp)); 2855 ASSERT(BP_GET_LEVEL(bp) == db->db_level); 2856 } 2857 2858 mutex_enter(&db->db_mtx); 2859 2860 #ifdef ZFS_DEBUG 2861 if (db->db_blkid == DMU_SPILL_BLKID) { 2862 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2863 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2864 db->db_blkptr == &dn->dn_phys->dn_spill); 2865 } 2866 #endif 2867 2868 if (db->db_level == 0) { 2869 mutex_enter(&dn->dn_mtx); 2870 if (db->db_blkid > dn->dn_phys->dn_maxblkid && 2871 db->db_blkid != DMU_SPILL_BLKID) 2872 dn->dn_phys->dn_maxblkid = db->db_blkid; 2873 mutex_exit(&dn->dn_mtx); 2874 2875 if (dn->dn_type == DMU_OT_DNODE) { 2876 dnode_phys_t *dnp = db->db.db_data; 2877 for (i = db->db.db_size >> DNODE_SHIFT; i > 0; 2878 i--, dnp++) { 2879 if (dnp->dn_type != DMU_OT_NONE) 2880 fill++; 2881 } 2882 } else { 2883 if (BP_IS_HOLE(bp)) { 2884 fill = 0; 2885 } else { 2886 fill = 1; 2887 } 2888 } 2889 } else { 2890 blkptr_t *ibp = db->db.db_data; 2891 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2892 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) { 2893 if (BP_IS_HOLE(ibp)) 2894 continue; 2895 fill += BP_GET_FILL(ibp); 2896 } 2897 } 2898 DB_DNODE_EXIT(db); 2899 2900 if (!BP_IS_EMBEDDED(bp)) 2901 bp->blk_fill = fill; 2902 2903 mutex_exit(&db->db_mtx); 2904 } 2905 2906 /* 2907 * The SPA will call this callback several times for each zio - once 2908 * for every physical child i/o (zio->io_phys_children times). This 2909 * allows the DMU to monitor the progress of each logical i/o. For example, 2910 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z 2911 * block. There may be a long delay before all copies/fragments are completed, 2912 * so this callback allows us to retire dirty space gradually, as the physical 2913 * i/os complete. 2914 */ 2915 /* ARGSUSED */ 2916 static void 2917 dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg) 2918 { 2919 dmu_buf_impl_t *db = arg; 2920 objset_t *os = db->db_objset; 2921 dsl_pool_t *dp = dmu_objset_pool(os); 2922 dbuf_dirty_record_t *dr; 2923 int delta = 0; 2924 2925 dr = db->db_data_pending; 2926 ASSERT3U(dr->dr_txg, ==, zio->io_txg); 2927 2928 /* 2929 * The callback will be called io_phys_children times. Retire one 2930 * portion of our dirty space each time we are called. Any rounding 2931 * error will be cleaned up by dsl_pool_sync()'s call to 2932 * dsl_pool_undirty_space(). 2933 */ 2934 delta = dr->dr_accounted / zio->io_phys_children; 2935 dsl_pool_undirty_space(dp, delta, zio->io_txg); 2936 } 2937 2938 /* ARGSUSED */ 2939 static void 2940 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb) 2941 { 2942 dmu_buf_impl_t *db = vdb; 2943 blkptr_t *bp_orig = &zio->io_bp_orig; 2944 blkptr_t *bp = db->db_blkptr; 2945 objset_t *os = db->db_objset; 2946 dmu_tx_t *tx = os->os_synctx; 2947 dbuf_dirty_record_t **drp, *dr; 2948 2949 ASSERT0(zio->io_error); 2950 ASSERT(db->db_blkptr == bp); 2951 2952 /* 2953 * For nopwrites and rewrites we ensure that the bp matches our 2954 * original and bypass all the accounting. 2955 */ 2956 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) { 2957 ASSERT(BP_EQUAL(bp, bp_orig)); 2958 } else { 2959 dsl_dataset_t *ds = os->os_dsl_dataset; 2960 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE); 2961 dsl_dataset_block_born(ds, bp, tx); 2962 } 2963 2964 mutex_enter(&db->db_mtx); 2965 2966 DBUF_VERIFY(db); 2967 2968 drp = &db->db_last_dirty; 2969 while ((dr = *drp) != db->db_data_pending) 2970 drp = &dr->dr_next; 2971 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2972 ASSERT(dr->dr_dbuf == db); 2973 ASSERT(dr->dr_next == NULL); 2974 *drp = dr->dr_next; 2975 2976 #ifdef ZFS_DEBUG 2977 if (db->db_blkid == DMU_SPILL_BLKID) { 2978 dnode_t *dn; 2979 2980 DB_DNODE_ENTER(db); 2981 dn = DB_DNODE(db); 2982 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2983 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2984 db->db_blkptr == &dn->dn_phys->dn_spill); 2985 DB_DNODE_EXIT(db); 2986 } 2987 #endif 2988 2989 if (db->db_level == 0) { 2990 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 2991 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN); 2992 if (db->db_state != DB_NOFILL) { 2993 if (dr->dt.dl.dr_data != db->db_buf) 2994 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 2995 db)); 2996 else if (!arc_released(db->db_buf)) 2997 arc_set_callback(db->db_buf, dbuf_do_evict, db); 2998 } 2999 } else { 3000 dnode_t *dn; 3001 3002 DB_DNODE_ENTER(db); 3003 dn = DB_DNODE(db); 3004 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 3005 ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift); 3006 if (!BP_IS_HOLE(db->db_blkptr)) { 3007 int epbs = 3008 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 3009 ASSERT3U(db->db_blkid, <=, 3010 dn->dn_phys->dn_maxblkid >> (db->db_level * epbs)); 3011 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, 3012 db->db.db_size); 3013 if (!arc_released(db->db_buf)) 3014 arc_set_callback(db->db_buf, dbuf_do_evict, db); 3015 } 3016 DB_DNODE_EXIT(db); 3017 mutex_destroy(&dr->dt.di.dr_mtx); 3018 list_destroy(&dr->dt.di.dr_children); 3019 } 3020 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 3021 3022 cv_broadcast(&db->db_changed); 3023 ASSERT(db->db_dirtycnt > 0); 3024 db->db_dirtycnt -= 1; 3025 db->db_data_pending = NULL; 3026 dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg); 3027 } 3028 3029 static void 3030 dbuf_write_nofill_ready(zio_t *zio) 3031 { 3032 dbuf_write_ready(zio, NULL, zio->io_private); 3033 } 3034 3035 static void 3036 dbuf_write_nofill_done(zio_t *zio) 3037 { 3038 dbuf_write_done(zio, NULL, zio->io_private); 3039 } 3040 3041 static void 3042 dbuf_write_override_ready(zio_t *zio) 3043 { 3044 dbuf_dirty_record_t *dr = zio->io_private; 3045 dmu_buf_impl_t *db = dr->dr_dbuf; 3046 3047 dbuf_write_ready(zio, NULL, db); 3048 } 3049 3050 static void 3051 dbuf_write_override_done(zio_t *zio) 3052 { 3053 dbuf_dirty_record_t *dr = zio->io_private; 3054 dmu_buf_impl_t *db = dr->dr_dbuf; 3055 blkptr_t *obp = &dr->dt.dl.dr_overridden_by; 3056 3057 mutex_enter(&db->db_mtx); 3058 if (!BP_EQUAL(zio->io_bp, obp)) { 3059 if (!BP_IS_HOLE(obp)) 3060 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp); 3061 arc_release(dr->dt.dl.dr_data, db); 3062 } 3063 mutex_exit(&db->db_mtx); 3064 3065 dbuf_write_done(zio, NULL, db); 3066 } 3067 3068 /* Issue I/O to commit a dirty buffer to disk. */ 3069 static void 3070 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) 3071 { 3072 dmu_buf_impl_t *db = dr->dr_dbuf; 3073 dnode_t *dn; 3074 objset_t *os; 3075 dmu_buf_impl_t *parent = db->db_parent; 3076 uint64_t txg = tx->tx_txg; 3077 zbookmark_phys_t zb; 3078 zio_prop_t zp; 3079 zio_t *zio; 3080 int wp_flag = 0; 3081 3082 DB_DNODE_ENTER(db); 3083 dn = DB_DNODE(db); 3084 os = dn->dn_objset; 3085 3086 if (db->db_state != DB_NOFILL) { 3087 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) { 3088 /* 3089 * Private object buffers are released here rather 3090 * than in dbuf_dirty() since they are only modified 3091 * in the syncing context and we don't want the 3092 * overhead of making multiple copies of the data. 3093 */ 3094 if (BP_IS_HOLE(db->db_blkptr)) { 3095 arc_buf_thaw(data); 3096 } else { 3097 dbuf_release_bp(db); 3098 } 3099 } 3100 } 3101 3102 if (parent != dn->dn_dbuf) { 3103 /* Our parent is an indirect block. */ 3104 /* We have a dirty parent that has been scheduled for write. */ 3105 ASSERT(parent && parent->db_data_pending); 3106 /* Our parent's buffer is one level closer to the dnode. */ 3107 ASSERT(db->db_level == parent->db_level-1); 3108 /* 3109 * We're about to modify our parent's db_data by modifying 3110 * our block pointer, so the parent must be released. 3111 */ 3112 ASSERT(arc_released(parent->db_buf)); 3113 zio = parent->db_data_pending->dr_zio; 3114 } else { 3115 /* Our parent is the dnode itself. */ 3116 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && 3117 db->db_blkid != DMU_SPILL_BLKID) || 3118 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); 3119 if (db->db_blkid != DMU_SPILL_BLKID) 3120 ASSERT3P(db->db_blkptr, ==, 3121 &dn->dn_phys->dn_blkptr[db->db_blkid]); 3122 zio = dn->dn_zio; 3123 } 3124 3125 ASSERT(db->db_level == 0 || data == db->db_buf); 3126 ASSERT3U(db->db_blkptr->blk_birth, <=, txg); 3127 ASSERT(zio); 3128 3129 SET_BOOKMARK(&zb, os->os_dsl_dataset ? 3130 os->os_dsl_dataset->ds_object : DMU_META_OBJSET, 3131 db->db.db_object, db->db_level, db->db_blkid); 3132 3133 if (db->db_blkid == DMU_SPILL_BLKID) 3134 wp_flag = WP_SPILL; 3135 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0; 3136 3137 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp); 3138 DB_DNODE_EXIT(db); 3139 3140 if (db->db_level == 0 && 3141 dr->dt.dl.dr_override_state == DR_OVERRIDDEN) { 3142 /* 3143 * The BP for this block has been provided by open context 3144 * (by dmu_sync() or dmu_buf_write_embedded()). 3145 */ 3146 void *contents = (data != NULL) ? data->b_data : NULL; 3147 3148 dr->dr_zio = zio_write(zio, os->os_spa, txg, 3149 db->db_blkptr, contents, db->db.db_size, &zp, 3150 dbuf_write_override_ready, NULL, dbuf_write_override_done, 3151 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 3152 mutex_enter(&db->db_mtx); 3153 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 3154 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by, 3155 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite); 3156 mutex_exit(&db->db_mtx); 3157 } else if (db->db_state == DB_NOFILL) { 3158 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF || 3159 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY); 3160 dr->dr_zio = zio_write(zio, os->os_spa, txg, 3161 db->db_blkptr, NULL, db->db.db_size, &zp, 3162 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db, 3163 ZIO_PRIORITY_ASYNC_WRITE, 3164 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb); 3165 } else { 3166 ASSERT(arc_released(data)); 3167 dr->dr_zio = arc_write(zio, os->os_spa, txg, 3168 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), 3169 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready, 3170 dbuf_write_physdone, dbuf_write_done, db, 3171 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 3172 } 3173 } 3174