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_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_immediate_evict = 0; 1844 db->db_freed_in_flight = 0; 1845 1846 if (blkid == DMU_BONUS_BLKID) { 1847 ASSERT3P(parent, ==, dn->dn_dbuf); 1848 db->db.db_size = DN_MAX_BONUSLEN - 1849 (dn->dn_nblkptr-1) * sizeof (blkptr_t); 1850 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 1851 db->db.db_offset = DMU_BONUS_BLKID; 1852 db->db_state = DB_UNCACHED; 1853 /* the bonus dbuf is not placed in the hash table */ 1854 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1855 return (db); 1856 } else if (blkid == DMU_SPILL_BLKID) { 1857 db->db.db_size = (blkptr != NULL) ? 1858 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE; 1859 db->db.db_offset = 0; 1860 } else { 1861 int blocksize = 1862 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz; 1863 db->db.db_size = blocksize; 1864 db->db.db_offset = db->db_blkid * blocksize; 1865 } 1866 1867 /* 1868 * Hold the dn_dbufs_mtx while we get the new dbuf 1869 * in the hash table *and* added to the dbufs list. 1870 * This prevents a possible deadlock with someone 1871 * trying to look up this dbuf before its added to the 1872 * dn_dbufs list. 1873 */ 1874 mutex_enter(&dn->dn_dbufs_mtx); 1875 db->db_state = DB_EVICTING; 1876 if ((odb = dbuf_hash_insert(db)) != NULL) { 1877 /* someone else inserted it first */ 1878 kmem_cache_free(dbuf_cache, db); 1879 mutex_exit(&dn->dn_dbufs_mtx); 1880 return (odb); 1881 } 1882 avl_add(&dn->dn_dbufs, db); 1883 if (db->db_level == 0 && db->db_blkid >= 1884 dn->dn_unlisted_l0_blkid) 1885 dn->dn_unlisted_l0_blkid = db->db_blkid + 1; 1886 db->db_state = DB_UNCACHED; 1887 mutex_exit(&dn->dn_dbufs_mtx); 1888 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1889 1890 if (parent && parent != dn->dn_dbuf) 1891 dbuf_add_ref(parent, db); 1892 1893 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1894 refcount_count(&dn->dn_holds) > 0); 1895 (void) refcount_add(&dn->dn_holds, db); 1896 atomic_inc_32(&dn->dn_dbufs_count); 1897 1898 dprintf_dbuf(db, "db=%p\n", db); 1899 1900 return (db); 1901 } 1902 1903 static int 1904 dbuf_do_evict(void *private) 1905 { 1906 dmu_buf_impl_t *db = private; 1907 1908 if (!MUTEX_HELD(&db->db_mtx)) 1909 mutex_enter(&db->db_mtx); 1910 1911 ASSERT(refcount_is_zero(&db->db_holds)); 1912 1913 if (db->db_state != DB_EVICTING) { 1914 ASSERT(db->db_state == DB_CACHED); 1915 DBUF_VERIFY(db); 1916 db->db_buf = NULL; 1917 dbuf_evict(db); 1918 } else { 1919 mutex_exit(&db->db_mtx); 1920 dbuf_destroy(db); 1921 } 1922 return (0); 1923 } 1924 1925 static void 1926 dbuf_destroy(dmu_buf_impl_t *db) 1927 { 1928 ASSERT(refcount_is_zero(&db->db_holds)); 1929 1930 if (db->db_blkid != DMU_BONUS_BLKID) { 1931 /* 1932 * If this dbuf is still on the dn_dbufs list, 1933 * remove it from that list. 1934 */ 1935 if (db->db_dnode_handle != NULL) { 1936 dnode_t *dn; 1937 1938 DB_DNODE_ENTER(db); 1939 dn = DB_DNODE(db); 1940 mutex_enter(&dn->dn_dbufs_mtx); 1941 avl_remove(&dn->dn_dbufs, db); 1942 atomic_dec_32(&dn->dn_dbufs_count); 1943 mutex_exit(&dn->dn_dbufs_mtx); 1944 DB_DNODE_EXIT(db); 1945 /* 1946 * Decrementing the dbuf count means that the hold 1947 * corresponding to the removed dbuf is no longer 1948 * discounted in dnode_move(), so the dnode cannot be 1949 * moved until after we release the hold. 1950 */ 1951 dnode_rele(dn, db); 1952 db->db_dnode_handle = NULL; 1953 } 1954 dbuf_hash_remove(db); 1955 } 1956 db->db_parent = NULL; 1957 db->db_buf = NULL; 1958 1959 ASSERT(db->db.db_data == NULL); 1960 ASSERT(db->db_hash_next == NULL); 1961 ASSERT(db->db_blkptr == NULL); 1962 ASSERT(db->db_data_pending == NULL); 1963 1964 kmem_cache_free(dbuf_cache, db); 1965 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1966 } 1967 1968 typedef struct dbuf_prefetch_arg { 1969 spa_t *dpa_spa; /* The spa to issue the prefetch in. */ 1970 zbookmark_phys_t dpa_zb; /* The target block to prefetch. */ 1971 int dpa_epbs; /* Entries (blkptr_t's) Per Block Shift. */ 1972 int dpa_curlevel; /* The current level that we're reading */ 1973 zio_priority_t dpa_prio; /* The priority I/Os should be issued at. */ 1974 zio_t *dpa_zio; /* The parent zio_t for all prefetches. */ 1975 arc_flags_t dpa_aflags; /* Flags to pass to the final prefetch. */ 1976 } dbuf_prefetch_arg_t; 1977 1978 /* 1979 * Actually issue the prefetch read for the block given. 1980 */ 1981 static void 1982 dbuf_issue_final_prefetch(dbuf_prefetch_arg_t *dpa, blkptr_t *bp) 1983 { 1984 if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) 1985 return; 1986 1987 arc_flags_t aflags = 1988 dpa->dpa_aflags | ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH; 1989 1990 ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); 1991 ASSERT3U(dpa->dpa_curlevel, ==, dpa->dpa_zb.zb_level); 1992 ASSERT(dpa->dpa_zio != NULL); 1993 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, bp, NULL, NULL, 1994 dpa->dpa_prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 1995 &aflags, &dpa->dpa_zb); 1996 } 1997 1998 /* 1999 * Called when an indirect block above our prefetch target is read in. This 2000 * will either read in the next indirect block down the tree or issue the actual 2001 * prefetch if the next block down is our target. 2002 */ 2003 static void 2004 dbuf_prefetch_indirect_done(zio_t *zio, arc_buf_t *abuf, void *private) 2005 { 2006 dbuf_prefetch_arg_t *dpa = private; 2007 2008 ASSERT3S(dpa->dpa_zb.zb_level, <, dpa->dpa_curlevel); 2009 ASSERT3S(dpa->dpa_curlevel, >, 0); 2010 if (zio != NULL) { 2011 ASSERT3S(BP_GET_LEVEL(zio->io_bp), ==, dpa->dpa_curlevel); 2012 ASSERT3U(BP_GET_LSIZE(zio->io_bp), ==, zio->io_size); 2013 ASSERT3P(zio->io_spa, ==, dpa->dpa_spa); 2014 } 2015 2016 dpa->dpa_curlevel--; 2017 2018 uint64_t nextblkid = dpa->dpa_zb.zb_blkid >> 2019 (dpa->dpa_epbs * (dpa->dpa_curlevel - dpa->dpa_zb.zb_level)); 2020 blkptr_t *bp = ((blkptr_t *)abuf->b_data) + 2021 P2PHASE(nextblkid, 1ULL << dpa->dpa_epbs); 2022 if (BP_IS_HOLE(bp) || (zio != NULL && zio->io_error != 0)) { 2023 kmem_free(dpa, sizeof (*dpa)); 2024 } else if (dpa->dpa_curlevel == dpa->dpa_zb.zb_level) { 2025 ASSERT3U(nextblkid, ==, dpa->dpa_zb.zb_blkid); 2026 dbuf_issue_final_prefetch(dpa, bp); 2027 kmem_free(dpa, sizeof (*dpa)); 2028 } else { 2029 arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; 2030 zbookmark_phys_t zb; 2031 2032 ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); 2033 2034 SET_BOOKMARK(&zb, dpa->dpa_zb.zb_objset, 2035 dpa->dpa_zb.zb_object, dpa->dpa_curlevel, nextblkid); 2036 2037 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, 2038 bp, dbuf_prefetch_indirect_done, dpa, dpa->dpa_prio, 2039 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2040 &iter_aflags, &zb); 2041 } 2042 (void) arc_buf_remove_ref(abuf, private); 2043 } 2044 2045 /* 2046 * Issue prefetch reads for the given block on the given level. If the indirect 2047 * blocks above that block are not in memory, we will read them in 2048 * asynchronously. As a result, this call never blocks waiting for a read to 2049 * complete. 2050 */ 2051 void 2052 dbuf_prefetch(dnode_t *dn, int64_t level, uint64_t blkid, zio_priority_t prio, 2053 arc_flags_t aflags) 2054 { 2055 blkptr_t bp; 2056 int epbs, nlevels, curlevel; 2057 uint64_t curblkid; 2058 2059 ASSERT(blkid != DMU_BONUS_BLKID); 2060 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 2061 2062 if (dnode_block_freed(dn, blkid)) 2063 return; 2064 2065 /* 2066 * This dnode hasn't been written to disk yet, so there's nothing to 2067 * prefetch. 2068 */ 2069 nlevels = dn->dn_phys->dn_nlevels; 2070 if (level >= nlevels || dn->dn_phys->dn_nblkptr == 0) 2071 return; 2072 2073 epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2074 if (dn->dn_phys->dn_maxblkid < blkid << (epbs * level)) 2075 return; 2076 2077 dmu_buf_impl_t *db = dbuf_find(dn->dn_objset, dn->dn_object, 2078 level, blkid); 2079 if (db != NULL) { 2080 mutex_exit(&db->db_mtx); 2081 /* 2082 * This dbuf already exists. It is either CACHED, or 2083 * (we assume) about to be read or filled. 2084 */ 2085 return; 2086 } 2087 2088 /* 2089 * Find the closest ancestor (indirect block) of the target block 2090 * that is present in the cache. In this indirect block, we will 2091 * find the bp that is at curlevel, curblkid. 2092 */ 2093 curlevel = level; 2094 curblkid = blkid; 2095 while (curlevel < nlevels - 1) { 2096 int parent_level = curlevel + 1; 2097 uint64_t parent_blkid = curblkid >> epbs; 2098 dmu_buf_impl_t *db; 2099 2100 if (dbuf_hold_impl(dn, parent_level, parent_blkid, 2101 FALSE, TRUE, FTAG, &db) == 0) { 2102 blkptr_t *bpp = db->db_buf->b_data; 2103 bp = bpp[P2PHASE(curblkid, 1 << epbs)]; 2104 dbuf_rele(db, FTAG); 2105 break; 2106 } 2107 2108 curlevel = parent_level; 2109 curblkid = parent_blkid; 2110 } 2111 2112 if (curlevel == nlevels - 1) { 2113 /* No cached indirect blocks found. */ 2114 ASSERT3U(curblkid, <, dn->dn_phys->dn_nblkptr); 2115 bp = dn->dn_phys->dn_blkptr[curblkid]; 2116 } 2117 if (BP_IS_HOLE(&bp)) 2118 return; 2119 2120 ASSERT3U(curlevel, ==, BP_GET_LEVEL(&bp)); 2121 2122 zio_t *pio = zio_root(dmu_objset_spa(dn->dn_objset), NULL, NULL, 2123 ZIO_FLAG_CANFAIL); 2124 2125 dbuf_prefetch_arg_t *dpa = kmem_zalloc(sizeof (*dpa), KM_SLEEP); 2126 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; 2127 SET_BOOKMARK(&dpa->dpa_zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, 2128 dn->dn_object, level, blkid); 2129 dpa->dpa_curlevel = curlevel; 2130 dpa->dpa_prio = prio; 2131 dpa->dpa_aflags = aflags; 2132 dpa->dpa_spa = dn->dn_objset->os_spa; 2133 dpa->dpa_epbs = epbs; 2134 dpa->dpa_zio = pio; 2135 2136 /* 2137 * If we have the indirect just above us, no need to do the asynchronous 2138 * prefetch chain; we'll just run the last step ourselves. If we're at 2139 * a higher level, though, we want to issue the prefetches for all the 2140 * indirect blocks asynchronously, so we can go on with whatever we were 2141 * doing. 2142 */ 2143 if (curlevel == level) { 2144 ASSERT3U(curblkid, ==, blkid); 2145 dbuf_issue_final_prefetch(dpa, &bp); 2146 kmem_free(dpa, sizeof (*dpa)); 2147 } else { 2148 arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; 2149 zbookmark_phys_t zb; 2150 2151 SET_BOOKMARK(&zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, 2152 dn->dn_object, curlevel, curblkid); 2153 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, 2154 &bp, dbuf_prefetch_indirect_done, dpa, prio, 2155 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2156 &iter_aflags, &zb); 2157 } 2158 /* 2159 * We use pio here instead of dpa_zio since it's possible that 2160 * dpa may have already been freed. 2161 */ 2162 zio_nowait(pio); 2163 } 2164 2165 /* 2166 * Returns with db_holds incremented, and db_mtx not held. 2167 * Note: dn_struct_rwlock must be held. 2168 */ 2169 int 2170 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, 2171 boolean_t fail_sparse, boolean_t fail_uncached, 2172 void *tag, dmu_buf_impl_t **dbp) 2173 { 2174 dmu_buf_impl_t *db, *parent = NULL; 2175 2176 ASSERT(blkid != DMU_BONUS_BLKID); 2177 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 2178 ASSERT3U(dn->dn_nlevels, >, level); 2179 2180 *dbp = NULL; 2181 top: 2182 /* dbuf_find() returns with db_mtx held */ 2183 db = dbuf_find(dn->dn_objset, dn->dn_object, level, blkid); 2184 2185 if (db == NULL) { 2186 blkptr_t *bp = NULL; 2187 int err; 2188 2189 if (fail_uncached) 2190 return (SET_ERROR(ENOENT)); 2191 2192 ASSERT3P(parent, ==, NULL); 2193 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp); 2194 if (fail_sparse) { 2195 if (err == 0 && bp && BP_IS_HOLE(bp)) 2196 err = SET_ERROR(ENOENT); 2197 if (err) { 2198 if (parent) 2199 dbuf_rele(parent, NULL); 2200 return (err); 2201 } 2202 } 2203 if (err && err != ENOENT) 2204 return (err); 2205 db = dbuf_create(dn, level, blkid, parent, bp); 2206 } 2207 2208 if (fail_uncached && db->db_state != DB_CACHED) { 2209 mutex_exit(&db->db_mtx); 2210 return (SET_ERROR(ENOENT)); 2211 } 2212 2213 if (db->db_buf && refcount_is_zero(&db->db_holds)) { 2214 arc_buf_add_ref(db->db_buf, db); 2215 if (db->db_buf->b_data == NULL) { 2216 dbuf_clear(db); 2217 if (parent) { 2218 dbuf_rele(parent, NULL); 2219 parent = NULL; 2220 } 2221 goto top; 2222 } 2223 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data); 2224 } 2225 2226 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf)); 2227 2228 /* 2229 * If this buffer is currently syncing out, and we are are 2230 * still referencing it from db_data, we need to make a copy 2231 * of it in case we decide we want to dirty it again in this txg. 2232 */ 2233 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 2234 dn->dn_object != DMU_META_DNODE_OBJECT && 2235 db->db_state == DB_CACHED && db->db_data_pending) { 2236 dbuf_dirty_record_t *dr = db->db_data_pending; 2237 2238 if (dr->dt.dl.dr_data == db->db_buf) { 2239 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2240 2241 dbuf_set_data(db, 2242 arc_buf_alloc(dn->dn_objset->os_spa, 2243 db->db.db_size, db, type)); 2244 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data, 2245 db->db.db_size); 2246 } 2247 } 2248 2249 (void) refcount_add(&db->db_holds, tag); 2250 DBUF_VERIFY(db); 2251 mutex_exit(&db->db_mtx); 2252 2253 /* NOTE: we can't rele the parent until after we drop the db_mtx */ 2254 if (parent) 2255 dbuf_rele(parent, NULL); 2256 2257 ASSERT3P(DB_DNODE(db), ==, dn); 2258 ASSERT3U(db->db_blkid, ==, blkid); 2259 ASSERT3U(db->db_level, ==, level); 2260 *dbp = db; 2261 2262 return (0); 2263 } 2264 2265 dmu_buf_impl_t * 2266 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag) 2267 { 2268 return (dbuf_hold_level(dn, 0, blkid, tag)); 2269 } 2270 2271 dmu_buf_impl_t * 2272 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag) 2273 { 2274 dmu_buf_impl_t *db; 2275 int err = dbuf_hold_impl(dn, level, blkid, FALSE, FALSE, tag, &db); 2276 return (err ? NULL : db); 2277 } 2278 2279 void 2280 dbuf_create_bonus(dnode_t *dn) 2281 { 2282 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 2283 2284 ASSERT(dn->dn_bonus == NULL); 2285 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL); 2286 } 2287 2288 int 2289 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx) 2290 { 2291 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2292 dnode_t *dn; 2293 2294 if (db->db_blkid != DMU_SPILL_BLKID) 2295 return (SET_ERROR(ENOTSUP)); 2296 if (blksz == 0) 2297 blksz = SPA_MINBLOCKSIZE; 2298 ASSERT3U(blksz, <=, spa_maxblocksize(dmu_objset_spa(db->db_objset))); 2299 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE); 2300 2301 DB_DNODE_ENTER(db); 2302 dn = DB_DNODE(db); 2303 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 2304 dbuf_new_size(db, blksz, tx); 2305 rw_exit(&dn->dn_struct_rwlock); 2306 DB_DNODE_EXIT(db); 2307 2308 return (0); 2309 } 2310 2311 void 2312 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx) 2313 { 2314 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx); 2315 } 2316 2317 #pragma weak dmu_buf_add_ref = dbuf_add_ref 2318 void 2319 dbuf_add_ref(dmu_buf_impl_t *db, void *tag) 2320 { 2321 int64_t holds = refcount_add(&db->db_holds, tag); 2322 ASSERT(holds > 1); 2323 } 2324 2325 #pragma weak dmu_buf_try_add_ref = dbuf_try_add_ref 2326 boolean_t 2327 dbuf_try_add_ref(dmu_buf_t *db_fake, objset_t *os, uint64_t obj, uint64_t blkid, 2328 void *tag) 2329 { 2330 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2331 dmu_buf_impl_t *found_db; 2332 boolean_t result = B_FALSE; 2333 2334 if (db->db_blkid == DMU_BONUS_BLKID) 2335 found_db = dbuf_find_bonus(os, obj); 2336 else 2337 found_db = dbuf_find(os, obj, 0, blkid); 2338 2339 if (found_db != NULL) { 2340 if (db == found_db && dbuf_refcount(db) > db->db_dirtycnt) { 2341 (void) refcount_add(&db->db_holds, tag); 2342 result = B_TRUE; 2343 } 2344 mutex_exit(&db->db_mtx); 2345 } 2346 return (result); 2347 } 2348 2349 /* 2350 * If you call dbuf_rele() you had better not be referencing the dnode handle 2351 * unless you have some other direct or indirect hold on the dnode. (An indirect 2352 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.) 2353 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the 2354 * dnode's parent dbuf evicting its dnode handles. 2355 */ 2356 void 2357 dbuf_rele(dmu_buf_impl_t *db, void *tag) 2358 { 2359 mutex_enter(&db->db_mtx); 2360 dbuf_rele_and_unlock(db, tag); 2361 } 2362 2363 void 2364 dmu_buf_rele(dmu_buf_t *db, void *tag) 2365 { 2366 dbuf_rele((dmu_buf_impl_t *)db, tag); 2367 } 2368 2369 /* 2370 * dbuf_rele() for an already-locked dbuf. This is necessary to allow 2371 * db_dirtycnt and db_holds to be updated atomically. 2372 */ 2373 void 2374 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) 2375 { 2376 int64_t holds; 2377 2378 ASSERT(MUTEX_HELD(&db->db_mtx)); 2379 DBUF_VERIFY(db); 2380 2381 /* 2382 * Remove the reference to the dbuf before removing its hold on the 2383 * dnode so we can guarantee in dnode_move() that a referenced bonus 2384 * buffer has a corresponding dnode hold. 2385 */ 2386 holds = refcount_remove(&db->db_holds, tag); 2387 ASSERT(holds >= 0); 2388 2389 /* 2390 * We can't freeze indirects if there is a possibility that they 2391 * may be modified in the current syncing context. 2392 */ 2393 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0)) 2394 arc_buf_freeze(db->db_buf); 2395 2396 if (holds == db->db_dirtycnt && 2397 db->db_level == 0 && db->db_immediate_evict) 2398 dbuf_evict_user(db); 2399 2400 if (holds == 0) { 2401 if (db->db_blkid == DMU_BONUS_BLKID) { 2402 dnode_t *dn; 2403 2404 /* 2405 * If the dnode moves here, we cannot cross this 2406 * barrier until the move completes. 2407 */ 2408 DB_DNODE_ENTER(db); 2409 2410 dn = DB_DNODE(db); 2411 atomic_dec_32(&dn->dn_dbufs_count); 2412 2413 /* 2414 * Decrementing the dbuf count means that the bonus 2415 * buffer's dnode hold is no longer discounted in 2416 * dnode_move(). The dnode cannot move until after 2417 * the dnode_rele_and_unlock() below. 2418 */ 2419 DB_DNODE_EXIT(db); 2420 2421 /* 2422 * Do not reference db after its lock is dropped. 2423 * Another thread may evict it. 2424 */ 2425 mutex_exit(&db->db_mtx); 2426 2427 /* 2428 * If the dnode has been freed, evict the bonus 2429 * buffer immediately. The data in the bonus 2430 * buffer is no longer relevant and this prevents 2431 * a stale bonus buffer from being associated 2432 * with this dnode_t should the dnode_t be reused 2433 * prior to being destroyed. 2434 */ 2435 mutex_enter(&dn->dn_mtx); 2436 if (dn->dn_type == DMU_OT_NONE || 2437 dn->dn_free_txg != 0) { 2438 /* 2439 * Drop dn_mtx. It is a leaf lock and 2440 * cannot be held when dnode_evict_bonus() 2441 * acquires other locks in order to 2442 * perform the eviction. 2443 * 2444 * Freed dnodes cannot be reused until the 2445 * last hold is released. Since this bonus 2446 * buffer has a hold, the dnode will remain 2447 * in the free state, even without dn_mtx 2448 * held, until the dnode_rele_and_unlock() 2449 * below. 2450 */ 2451 mutex_exit(&dn->dn_mtx); 2452 dnode_evict_bonus(dn); 2453 mutex_enter(&dn->dn_mtx); 2454 } 2455 dnode_rele_and_unlock(dn, db); 2456 } else if (db->db_buf == NULL) { 2457 /* 2458 * This is a special case: we never associated this 2459 * dbuf with any data allocated from the ARC. 2460 */ 2461 ASSERT(db->db_state == DB_UNCACHED || 2462 db->db_state == DB_NOFILL); 2463 dbuf_evict(db); 2464 } else if (arc_released(db->db_buf)) { 2465 arc_buf_t *buf = db->db_buf; 2466 /* 2467 * This dbuf has anonymous data associated with it. 2468 */ 2469 dbuf_clear_data(db); 2470 VERIFY(arc_buf_remove_ref(buf, db)); 2471 dbuf_evict(db); 2472 } else { 2473 VERIFY(!arc_buf_remove_ref(db->db_buf, db)); 2474 2475 /* 2476 * A dbuf will be eligible for eviction if either the 2477 * 'primarycache' property is set or a duplicate 2478 * copy of this buffer is already cached in the arc. 2479 * 2480 * In the case of the 'primarycache' a buffer 2481 * is considered for eviction if it matches the 2482 * criteria set in the property. 2483 * 2484 * To decide if our buffer is considered a 2485 * duplicate, we must call into the arc to determine 2486 * if multiple buffers are referencing the same 2487 * block on-disk. If so, then we simply evict 2488 * ourselves. 2489 */ 2490 if (!DBUF_IS_CACHEABLE(db)) { 2491 if (db->db_blkptr != NULL && 2492 !BP_IS_HOLE(db->db_blkptr) && 2493 !BP_IS_EMBEDDED(db->db_blkptr)) { 2494 spa_t *spa = 2495 dmu_objset_spa(db->db_objset); 2496 blkptr_t bp = *db->db_blkptr; 2497 dbuf_clear(db); 2498 arc_freed(spa, &bp); 2499 } else { 2500 dbuf_clear(db); 2501 } 2502 } else if (db->db_objset->os_evicting || 2503 arc_buf_eviction_needed(db->db_buf)) { 2504 dbuf_clear(db); 2505 } else { 2506 mutex_exit(&db->db_mtx); 2507 } 2508 } 2509 } else { 2510 mutex_exit(&db->db_mtx); 2511 } 2512 } 2513 2514 #pragma weak dmu_buf_refcount = dbuf_refcount 2515 uint64_t 2516 dbuf_refcount(dmu_buf_impl_t *db) 2517 { 2518 return (refcount_count(&db->db_holds)); 2519 } 2520 2521 void * 2522 dmu_buf_replace_user(dmu_buf_t *db_fake, dmu_buf_user_t *old_user, 2523 dmu_buf_user_t *new_user) 2524 { 2525 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2526 2527 mutex_enter(&db->db_mtx); 2528 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2529 if (db->db_user == old_user) 2530 db->db_user = new_user; 2531 else 2532 old_user = db->db_user; 2533 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2534 mutex_exit(&db->db_mtx); 2535 2536 return (old_user); 2537 } 2538 2539 void * 2540 dmu_buf_set_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2541 { 2542 return (dmu_buf_replace_user(db_fake, NULL, user)); 2543 } 2544 2545 void * 2546 dmu_buf_set_user_ie(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2547 { 2548 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2549 2550 db->db_immediate_evict = TRUE; 2551 return (dmu_buf_set_user(db_fake, user)); 2552 } 2553 2554 void * 2555 dmu_buf_remove_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2556 { 2557 return (dmu_buf_replace_user(db_fake, user, NULL)); 2558 } 2559 2560 void * 2561 dmu_buf_get_user(dmu_buf_t *db_fake) 2562 { 2563 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2564 2565 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2566 return (db->db_user); 2567 } 2568 2569 void 2570 dmu_buf_user_evict_wait() 2571 { 2572 taskq_wait(dbu_evict_taskq); 2573 } 2574 2575 boolean_t 2576 dmu_buf_freeable(dmu_buf_t *dbuf) 2577 { 2578 boolean_t res = B_FALSE; 2579 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 2580 2581 if (db->db_blkptr) 2582 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset, 2583 db->db_blkptr, db->db_blkptr->blk_birth); 2584 2585 return (res); 2586 } 2587 2588 blkptr_t * 2589 dmu_buf_get_blkptr(dmu_buf_t *db) 2590 { 2591 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; 2592 return (dbi->db_blkptr); 2593 } 2594 2595 static void 2596 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db) 2597 { 2598 /* ASSERT(dmu_tx_is_syncing(tx) */ 2599 ASSERT(MUTEX_HELD(&db->db_mtx)); 2600 2601 if (db->db_blkptr != NULL) 2602 return; 2603 2604 if (db->db_blkid == DMU_SPILL_BLKID) { 2605 db->db_blkptr = &dn->dn_phys->dn_spill; 2606 BP_ZERO(db->db_blkptr); 2607 return; 2608 } 2609 if (db->db_level == dn->dn_phys->dn_nlevels-1) { 2610 /* 2611 * This buffer was allocated at a time when there was 2612 * no available blkptrs from the dnode, or it was 2613 * inappropriate to hook it in (i.e., nlevels mis-match). 2614 */ 2615 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr); 2616 ASSERT(db->db_parent == NULL); 2617 db->db_parent = dn->dn_dbuf; 2618 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid]; 2619 DBUF_VERIFY(db); 2620 } else { 2621 dmu_buf_impl_t *parent = db->db_parent; 2622 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2623 2624 ASSERT(dn->dn_phys->dn_nlevels > 1); 2625 if (parent == NULL) { 2626 mutex_exit(&db->db_mtx); 2627 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2628 parent = dbuf_hold_level(dn, db->db_level + 1, 2629 db->db_blkid >> epbs, db); 2630 rw_exit(&dn->dn_struct_rwlock); 2631 mutex_enter(&db->db_mtx); 2632 db->db_parent = parent; 2633 } 2634 db->db_blkptr = (blkptr_t *)parent->db.db_data + 2635 (db->db_blkid & ((1ULL << epbs) - 1)); 2636 DBUF_VERIFY(db); 2637 } 2638 } 2639 2640 static void 2641 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2642 { 2643 dmu_buf_impl_t *db = dr->dr_dbuf; 2644 dnode_t *dn; 2645 zio_t *zio; 2646 2647 ASSERT(dmu_tx_is_syncing(tx)); 2648 2649 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2650 2651 mutex_enter(&db->db_mtx); 2652 2653 ASSERT(db->db_level > 0); 2654 DBUF_VERIFY(db); 2655 2656 /* Read the block if it hasn't been read yet. */ 2657 if (db->db_buf == NULL) { 2658 mutex_exit(&db->db_mtx); 2659 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); 2660 mutex_enter(&db->db_mtx); 2661 } 2662 ASSERT3U(db->db_state, ==, DB_CACHED); 2663 ASSERT(db->db_buf != NULL); 2664 2665 DB_DNODE_ENTER(db); 2666 dn = DB_DNODE(db); 2667 /* Indirect block size must match what the dnode thinks it is. */ 2668 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2669 dbuf_check_blkptr(dn, db); 2670 DB_DNODE_EXIT(db); 2671 2672 /* Provide the pending dirty record to child dbufs */ 2673 db->db_data_pending = dr; 2674 2675 mutex_exit(&db->db_mtx); 2676 dbuf_write(dr, db->db_buf, tx); 2677 2678 zio = dr->dr_zio; 2679 mutex_enter(&dr->dt.di.dr_mtx); 2680 dbuf_sync_list(&dr->dt.di.dr_children, db->db_level - 1, tx); 2681 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2682 mutex_exit(&dr->dt.di.dr_mtx); 2683 zio_nowait(zio); 2684 } 2685 2686 static void 2687 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2688 { 2689 arc_buf_t **datap = &dr->dt.dl.dr_data; 2690 dmu_buf_impl_t *db = dr->dr_dbuf; 2691 dnode_t *dn; 2692 objset_t *os; 2693 uint64_t txg = tx->tx_txg; 2694 2695 ASSERT(dmu_tx_is_syncing(tx)); 2696 2697 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2698 2699 mutex_enter(&db->db_mtx); 2700 /* 2701 * To be synced, we must be dirtied. But we 2702 * might have been freed after the dirty. 2703 */ 2704 if (db->db_state == DB_UNCACHED) { 2705 /* This buffer has been freed since it was dirtied */ 2706 ASSERT(db->db.db_data == NULL); 2707 } else if (db->db_state == DB_FILL) { 2708 /* This buffer was freed and is now being re-filled */ 2709 ASSERT(db->db.db_data != dr->dt.dl.dr_data); 2710 } else { 2711 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); 2712 } 2713 DBUF_VERIFY(db); 2714 2715 DB_DNODE_ENTER(db); 2716 dn = DB_DNODE(db); 2717 2718 if (db->db_blkid == DMU_SPILL_BLKID) { 2719 mutex_enter(&dn->dn_mtx); 2720 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR; 2721 mutex_exit(&dn->dn_mtx); 2722 } 2723 2724 /* 2725 * If this is a bonus buffer, simply copy the bonus data into the 2726 * dnode. It will be written out when the dnode is synced (and it 2727 * will be synced, since it must have been dirty for dbuf_sync to 2728 * be called). 2729 */ 2730 if (db->db_blkid == DMU_BONUS_BLKID) { 2731 dbuf_dirty_record_t **drp; 2732 2733 ASSERT(*datap != NULL); 2734 ASSERT0(db->db_level); 2735 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN); 2736 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen); 2737 DB_DNODE_EXIT(db); 2738 2739 if (*datap != db->db.db_data) { 2740 zio_buf_free(*datap, DN_MAX_BONUSLEN); 2741 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 2742 } 2743 db->db_data_pending = NULL; 2744 drp = &db->db_last_dirty; 2745 while (*drp != dr) 2746 drp = &(*drp)->dr_next; 2747 ASSERT(dr->dr_next == NULL); 2748 ASSERT(dr->dr_dbuf == db); 2749 *drp = dr->dr_next; 2750 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2751 ASSERT(db->db_dirtycnt > 0); 2752 db->db_dirtycnt -= 1; 2753 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2754 return; 2755 } 2756 2757 os = dn->dn_objset; 2758 2759 /* 2760 * This function may have dropped the db_mtx lock allowing a dmu_sync 2761 * operation to sneak in. As a result, we need to ensure that we 2762 * don't check the dr_override_state until we have returned from 2763 * dbuf_check_blkptr. 2764 */ 2765 dbuf_check_blkptr(dn, db); 2766 2767 /* 2768 * If this buffer is in the middle of an immediate write, 2769 * wait for the synchronous IO to complete. 2770 */ 2771 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) { 2772 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); 2773 cv_wait(&db->db_changed, &db->db_mtx); 2774 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN); 2775 } 2776 2777 if (db->db_state != DB_NOFILL && 2778 dn->dn_object != DMU_META_DNODE_OBJECT && 2779 refcount_count(&db->db_holds) > 1 && 2780 dr->dt.dl.dr_override_state != DR_OVERRIDDEN && 2781 *datap == db->db_buf) { 2782 /* 2783 * If this buffer is currently "in use" (i.e., there 2784 * are active holds and db_data still references it), 2785 * then make a copy before we start the write so that 2786 * any modifications from the open txg will not leak 2787 * into this write. 2788 * 2789 * NOTE: this copy does not need to be made for 2790 * objects only modified in the syncing context (e.g. 2791 * DNONE_DNODE blocks). 2792 */ 2793 int blksz = arc_buf_size(*datap); 2794 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2795 *datap = arc_buf_alloc(os->os_spa, blksz, db, type); 2796 bcopy(db->db.db_data, (*datap)->b_data, blksz); 2797 } 2798 db->db_data_pending = dr; 2799 2800 mutex_exit(&db->db_mtx); 2801 2802 dbuf_write(dr, *datap, tx); 2803 2804 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2805 if (dn->dn_object == DMU_META_DNODE_OBJECT) { 2806 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr); 2807 DB_DNODE_EXIT(db); 2808 } else { 2809 /* 2810 * Although zio_nowait() does not "wait for an IO", it does 2811 * initiate the IO. If this is an empty write it seems plausible 2812 * that the IO could actually be completed before the nowait 2813 * returns. We need to DB_DNODE_EXIT() first in case 2814 * zio_nowait() invalidates the dbuf. 2815 */ 2816 DB_DNODE_EXIT(db); 2817 zio_nowait(dr->dr_zio); 2818 } 2819 } 2820 2821 void 2822 dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx) 2823 { 2824 dbuf_dirty_record_t *dr; 2825 2826 while (dr = list_head(list)) { 2827 if (dr->dr_zio != NULL) { 2828 /* 2829 * If we find an already initialized zio then we 2830 * are processing the meta-dnode, and we have finished. 2831 * The dbufs for all dnodes are put back on the list 2832 * during processing, so that we can zio_wait() 2833 * these IOs after initiating all child IOs. 2834 */ 2835 ASSERT3U(dr->dr_dbuf->db.db_object, ==, 2836 DMU_META_DNODE_OBJECT); 2837 break; 2838 } 2839 if (dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID && 2840 dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) { 2841 VERIFY3U(dr->dr_dbuf->db_level, ==, level); 2842 } 2843 list_remove(list, dr); 2844 if (dr->dr_dbuf->db_level > 0) 2845 dbuf_sync_indirect(dr, tx); 2846 else 2847 dbuf_sync_leaf(dr, tx); 2848 } 2849 } 2850 2851 /* ARGSUSED */ 2852 static void 2853 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb) 2854 { 2855 dmu_buf_impl_t *db = vdb; 2856 dnode_t *dn; 2857 blkptr_t *bp = zio->io_bp; 2858 blkptr_t *bp_orig = &zio->io_bp_orig; 2859 spa_t *spa = zio->io_spa; 2860 int64_t delta; 2861 uint64_t fill = 0; 2862 int i; 2863 2864 ASSERT3P(db->db_blkptr, ==, bp); 2865 2866 DB_DNODE_ENTER(db); 2867 dn = DB_DNODE(db); 2868 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig); 2869 dnode_diduse_space(dn, delta - zio->io_prev_space_delta); 2870 zio->io_prev_space_delta = delta; 2871 2872 if (bp->blk_birth != 0) { 2873 ASSERT((db->db_blkid != DMU_SPILL_BLKID && 2874 BP_GET_TYPE(bp) == dn->dn_type) || 2875 (db->db_blkid == DMU_SPILL_BLKID && 2876 BP_GET_TYPE(bp) == dn->dn_bonustype) || 2877 BP_IS_EMBEDDED(bp)); 2878 ASSERT(BP_GET_LEVEL(bp) == db->db_level); 2879 } 2880 2881 mutex_enter(&db->db_mtx); 2882 2883 #ifdef ZFS_DEBUG 2884 if (db->db_blkid == DMU_SPILL_BLKID) { 2885 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2886 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2887 db->db_blkptr == &dn->dn_phys->dn_spill); 2888 } 2889 #endif 2890 2891 if (db->db_level == 0) { 2892 mutex_enter(&dn->dn_mtx); 2893 if (db->db_blkid > dn->dn_phys->dn_maxblkid && 2894 db->db_blkid != DMU_SPILL_BLKID) 2895 dn->dn_phys->dn_maxblkid = db->db_blkid; 2896 mutex_exit(&dn->dn_mtx); 2897 2898 if (dn->dn_type == DMU_OT_DNODE) { 2899 dnode_phys_t *dnp = db->db.db_data; 2900 for (i = db->db.db_size >> DNODE_SHIFT; i > 0; 2901 i--, dnp++) { 2902 if (dnp->dn_type != DMU_OT_NONE) 2903 fill++; 2904 } 2905 } else { 2906 if (BP_IS_HOLE(bp)) { 2907 fill = 0; 2908 } else { 2909 fill = 1; 2910 } 2911 } 2912 } else { 2913 blkptr_t *ibp = db->db.db_data; 2914 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2915 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) { 2916 if (BP_IS_HOLE(ibp)) 2917 continue; 2918 fill += BP_GET_FILL(ibp); 2919 } 2920 } 2921 DB_DNODE_EXIT(db); 2922 2923 if (!BP_IS_EMBEDDED(bp)) 2924 bp->blk_fill = fill; 2925 2926 mutex_exit(&db->db_mtx); 2927 } 2928 2929 /* 2930 * The SPA will call this callback several times for each zio - once 2931 * for every physical child i/o (zio->io_phys_children times). This 2932 * allows the DMU to monitor the progress of each logical i/o. For example, 2933 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z 2934 * block. There may be a long delay before all copies/fragments are completed, 2935 * so this callback allows us to retire dirty space gradually, as the physical 2936 * i/os complete. 2937 */ 2938 /* ARGSUSED */ 2939 static void 2940 dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg) 2941 { 2942 dmu_buf_impl_t *db = arg; 2943 objset_t *os = db->db_objset; 2944 dsl_pool_t *dp = dmu_objset_pool(os); 2945 dbuf_dirty_record_t *dr; 2946 int delta = 0; 2947 2948 dr = db->db_data_pending; 2949 ASSERT3U(dr->dr_txg, ==, zio->io_txg); 2950 2951 /* 2952 * The callback will be called io_phys_children times. Retire one 2953 * portion of our dirty space each time we are called. Any rounding 2954 * error will be cleaned up by dsl_pool_sync()'s call to 2955 * dsl_pool_undirty_space(). 2956 */ 2957 delta = dr->dr_accounted / zio->io_phys_children; 2958 dsl_pool_undirty_space(dp, delta, zio->io_txg); 2959 } 2960 2961 /* ARGSUSED */ 2962 static void 2963 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb) 2964 { 2965 dmu_buf_impl_t *db = vdb; 2966 blkptr_t *bp_orig = &zio->io_bp_orig; 2967 blkptr_t *bp = db->db_blkptr; 2968 objset_t *os = db->db_objset; 2969 dmu_tx_t *tx = os->os_synctx; 2970 dbuf_dirty_record_t **drp, *dr; 2971 2972 ASSERT0(zio->io_error); 2973 ASSERT(db->db_blkptr == bp); 2974 2975 /* 2976 * For nopwrites and rewrites we ensure that the bp matches our 2977 * original and bypass all the accounting. 2978 */ 2979 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) { 2980 ASSERT(BP_EQUAL(bp, bp_orig)); 2981 } else { 2982 dsl_dataset_t *ds = os->os_dsl_dataset; 2983 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE); 2984 dsl_dataset_block_born(ds, bp, tx); 2985 } 2986 2987 mutex_enter(&db->db_mtx); 2988 2989 DBUF_VERIFY(db); 2990 2991 drp = &db->db_last_dirty; 2992 while ((dr = *drp) != db->db_data_pending) 2993 drp = &dr->dr_next; 2994 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2995 ASSERT(dr->dr_dbuf == db); 2996 ASSERT(dr->dr_next == NULL); 2997 *drp = dr->dr_next; 2998 2999 #ifdef ZFS_DEBUG 3000 if (db->db_blkid == DMU_SPILL_BLKID) { 3001 dnode_t *dn; 3002 3003 DB_DNODE_ENTER(db); 3004 dn = DB_DNODE(db); 3005 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 3006 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 3007 db->db_blkptr == &dn->dn_phys->dn_spill); 3008 DB_DNODE_EXIT(db); 3009 } 3010 #endif 3011 3012 if (db->db_level == 0) { 3013 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 3014 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN); 3015 if (db->db_state != DB_NOFILL) { 3016 if (dr->dt.dl.dr_data != db->db_buf) 3017 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 3018 db)); 3019 else if (!arc_released(db->db_buf)) 3020 arc_set_callback(db->db_buf, dbuf_do_evict, db); 3021 } 3022 } else { 3023 dnode_t *dn; 3024 3025 DB_DNODE_ENTER(db); 3026 dn = DB_DNODE(db); 3027 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 3028 ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift); 3029 if (!BP_IS_HOLE(db->db_blkptr)) { 3030 int epbs = 3031 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 3032 ASSERT3U(db->db_blkid, <=, 3033 dn->dn_phys->dn_maxblkid >> (db->db_level * epbs)); 3034 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, 3035 db->db.db_size); 3036 if (!arc_released(db->db_buf)) 3037 arc_set_callback(db->db_buf, dbuf_do_evict, db); 3038 } 3039 DB_DNODE_EXIT(db); 3040 mutex_destroy(&dr->dt.di.dr_mtx); 3041 list_destroy(&dr->dt.di.dr_children); 3042 } 3043 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 3044 3045 cv_broadcast(&db->db_changed); 3046 ASSERT(db->db_dirtycnt > 0); 3047 db->db_dirtycnt -= 1; 3048 db->db_data_pending = NULL; 3049 dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg); 3050 } 3051 3052 static void 3053 dbuf_write_nofill_ready(zio_t *zio) 3054 { 3055 dbuf_write_ready(zio, NULL, zio->io_private); 3056 } 3057 3058 static void 3059 dbuf_write_nofill_done(zio_t *zio) 3060 { 3061 dbuf_write_done(zio, NULL, zio->io_private); 3062 } 3063 3064 static void 3065 dbuf_write_override_ready(zio_t *zio) 3066 { 3067 dbuf_dirty_record_t *dr = zio->io_private; 3068 dmu_buf_impl_t *db = dr->dr_dbuf; 3069 3070 dbuf_write_ready(zio, NULL, db); 3071 } 3072 3073 static void 3074 dbuf_write_override_done(zio_t *zio) 3075 { 3076 dbuf_dirty_record_t *dr = zio->io_private; 3077 dmu_buf_impl_t *db = dr->dr_dbuf; 3078 blkptr_t *obp = &dr->dt.dl.dr_overridden_by; 3079 3080 mutex_enter(&db->db_mtx); 3081 if (!BP_EQUAL(zio->io_bp, obp)) { 3082 if (!BP_IS_HOLE(obp)) 3083 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp); 3084 arc_release(dr->dt.dl.dr_data, db); 3085 } 3086 mutex_exit(&db->db_mtx); 3087 3088 dbuf_write_done(zio, NULL, db); 3089 } 3090 3091 /* Issue I/O to commit a dirty buffer to disk. */ 3092 static void 3093 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) 3094 { 3095 dmu_buf_impl_t *db = dr->dr_dbuf; 3096 dnode_t *dn; 3097 objset_t *os; 3098 dmu_buf_impl_t *parent = db->db_parent; 3099 uint64_t txg = tx->tx_txg; 3100 zbookmark_phys_t zb; 3101 zio_prop_t zp; 3102 zio_t *zio; 3103 int wp_flag = 0; 3104 3105 DB_DNODE_ENTER(db); 3106 dn = DB_DNODE(db); 3107 os = dn->dn_objset; 3108 3109 if (db->db_state != DB_NOFILL) { 3110 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) { 3111 /* 3112 * Private object buffers are released here rather 3113 * than in dbuf_dirty() since they are only modified 3114 * in the syncing context and we don't want the 3115 * overhead of making multiple copies of the data. 3116 */ 3117 if (BP_IS_HOLE(db->db_blkptr)) { 3118 arc_buf_thaw(data); 3119 } else { 3120 dbuf_release_bp(db); 3121 } 3122 } 3123 } 3124 3125 if (parent != dn->dn_dbuf) { 3126 /* Our parent is an indirect block. */ 3127 /* We have a dirty parent that has been scheduled for write. */ 3128 ASSERT(parent && parent->db_data_pending); 3129 /* Our parent's buffer is one level closer to the dnode. */ 3130 ASSERT(db->db_level == parent->db_level-1); 3131 /* 3132 * We're about to modify our parent's db_data by modifying 3133 * our block pointer, so the parent must be released. 3134 */ 3135 ASSERT(arc_released(parent->db_buf)); 3136 zio = parent->db_data_pending->dr_zio; 3137 } else { 3138 /* Our parent is the dnode itself. */ 3139 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && 3140 db->db_blkid != DMU_SPILL_BLKID) || 3141 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); 3142 if (db->db_blkid != DMU_SPILL_BLKID) 3143 ASSERT3P(db->db_blkptr, ==, 3144 &dn->dn_phys->dn_blkptr[db->db_blkid]); 3145 zio = dn->dn_zio; 3146 } 3147 3148 ASSERT(db->db_level == 0 || data == db->db_buf); 3149 ASSERT3U(db->db_blkptr->blk_birth, <=, txg); 3150 ASSERT(zio); 3151 3152 SET_BOOKMARK(&zb, os->os_dsl_dataset ? 3153 os->os_dsl_dataset->ds_object : DMU_META_OBJSET, 3154 db->db.db_object, db->db_level, db->db_blkid); 3155 3156 if (db->db_blkid == DMU_SPILL_BLKID) 3157 wp_flag = WP_SPILL; 3158 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0; 3159 3160 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp); 3161 DB_DNODE_EXIT(db); 3162 3163 if (db->db_level == 0 && 3164 dr->dt.dl.dr_override_state == DR_OVERRIDDEN) { 3165 /* 3166 * The BP for this block has been provided by open context 3167 * (by dmu_sync() or dmu_buf_write_embedded()). 3168 */ 3169 void *contents = (data != NULL) ? data->b_data : NULL; 3170 3171 dr->dr_zio = zio_write(zio, os->os_spa, txg, 3172 db->db_blkptr, contents, db->db.db_size, &zp, 3173 dbuf_write_override_ready, NULL, dbuf_write_override_done, 3174 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 3175 mutex_enter(&db->db_mtx); 3176 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 3177 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by, 3178 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite); 3179 mutex_exit(&db->db_mtx); 3180 } else if (db->db_state == DB_NOFILL) { 3181 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF || 3182 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY); 3183 dr->dr_zio = zio_write(zio, os->os_spa, txg, 3184 db->db_blkptr, NULL, db->db.db_size, &zp, 3185 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db, 3186 ZIO_PRIORITY_ASYNC_WRITE, 3187 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb); 3188 } else { 3189 ASSERT(arc_released(data)); 3190 dr->dr_zio = arc_write(zio, os->os_spa, txg, 3191 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), 3192 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready, 3193 dbuf_write_physdone, dbuf_write_done, db, 3194 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 3195 } 3196 } 3197