1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 24 * Copyright (c) 2012, 2015 by Delphix. All rights reserved. 25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved. 26 * Copyright (c) 2013, Joyent, Inc. All rights reserved. 27 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. 28 */ 29 30 #include <sys/zfs_context.h> 31 #include <sys/dmu.h> 32 #include <sys/dmu_send.h> 33 #include <sys/dmu_impl.h> 34 #include <sys/dbuf.h> 35 #include <sys/dmu_objset.h> 36 #include <sys/dsl_dataset.h> 37 #include <sys/dsl_dir.h> 38 #include <sys/dmu_tx.h> 39 #include <sys/spa.h> 40 #include <sys/zio.h> 41 #include <sys/dmu_zfetch.h> 42 #include <sys/sa.h> 43 #include <sys/sa_impl.h> 44 #include <sys/zfeature.h> 45 #include <sys/blkptr.h> 46 #include <sys/range_tree.h> 47 48 /* 49 * Number of times that zfs_free_range() took the slow path while doing 50 * a zfs receive. A nonzero value indicates a potential performance problem. 51 */ 52 uint64_t zfs_free_range_recv_miss; 53 54 static void dbuf_destroy(dmu_buf_impl_t *db); 55 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 56 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx); 57 58 #ifndef __lint 59 extern inline void dmu_buf_init_user(dmu_buf_user_t *dbu, 60 dmu_buf_evict_func_t *evict_func, dmu_buf_t **clear_on_evict_dbufp); 61 #endif /* ! __lint */ 62 63 /* 64 * Global data structures and functions for the dbuf cache. 65 */ 66 static kmem_cache_t *dbuf_cache; 67 static taskq_t *dbu_evict_taskq; 68 69 /* ARGSUSED */ 70 static int 71 dbuf_cons(void *vdb, void *unused, int kmflag) 72 { 73 dmu_buf_impl_t *db = vdb; 74 bzero(db, sizeof (dmu_buf_impl_t)); 75 76 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL); 77 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL); 78 refcount_create(&db->db_holds); 79 80 return (0); 81 } 82 83 /* ARGSUSED */ 84 static void 85 dbuf_dest(void *vdb, void *unused) 86 { 87 dmu_buf_impl_t *db = vdb; 88 mutex_destroy(&db->db_mtx); 89 cv_destroy(&db->db_changed); 90 refcount_destroy(&db->db_holds); 91 } 92 93 /* 94 * dbuf hash table routines 95 */ 96 static dbuf_hash_table_t dbuf_hash_table; 97 98 static uint64_t dbuf_hash_count; 99 100 static uint64_t 101 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid) 102 { 103 uintptr_t osv = (uintptr_t)os; 104 uint64_t crc = -1ULL; 105 106 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); 107 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF]; 108 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF]; 109 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF]; 110 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF]; 111 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF]; 112 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF]; 113 114 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16); 115 116 return (crc); 117 } 118 119 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid); 120 121 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \ 122 ((dbuf)->db.db_object == (obj) && \ 123 (dbuf)->db_objset == (os) && \ 124 (dbuf)->db_level == (level) && \ 125 (dbuf)->db_blkid == (blkid)) 126 127 dmu_buf_impl_t * 128 dbuf_find(objset_t *os, uint64_t obj, uint8_t level, uint64_t blkid) 129 { 130 dbuf_hash_table_t *h = &dbuf_hash_table; 131 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 132 uint64_t idx = hv & h->hash_table_mask; 133 dmu_buf_impl_t *db; 134 135 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 136 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) { 137 if (DBUF_EQUAL(db, os, obj, level, blkid)) { 138 mutex_enter(&db->db_mtx); 139 if (db->db_state != DB_EVICTING) { 140 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 141 return (db); 142 } 143 mutex_exit(&db->db_mtx); 144 } 145 } 146 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 147 return (NULL); 148 } 149 150 static dmu_buf_impl_t * 151 dbuf_find_bonus(objset_t *os, uint64_t object) 152 { 153 dnode_t *dn; 154 dmu_buf_impl_t *db = NULL; 155 156 if (dnode_hold(os, object, FTAG, &dn) == 0) { 157 rw_enter(&dn->dn_struct_rwlock, RW_READER); 158 if (dn->dn_bonus != NULL) { 159 db = dn->dn_bonus; 160 mutex_enter(&db->db_mtx); 161 } 162 rw_exit(&dn->dn_struct_rwlock); 163 dnode_rele(dn, FTAG); 164 } 165 return (db); 166 } 167 168 /* 169 * Insert an entry into the hash table. If there is already an element 170 * equal to elem in the hash table, then the already existing element 171 * will be returned and the new element will not be inserted. 172 * Otherwise returns NULL. 173 */ 174 static dmu_buf_impl_t * 175 dbuf_hash_insert(dmu_buf_impl_t *db) 176 { 177 dbuf_hash_table_t *h = &dbuf_hash_table; 178 objset_t *os = db->db_objset; 179 uint64_t obj = db->db.db_object; 180 int level = db->db_level; 181 uint64_t blkid = db->db_blkid; 182 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 183 uint64_t idx = hv & h->hash_table_mask; 184 dmu_buf_impl_t *dbf; 185 186 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 187 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) { 188 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) { 189 mutex_enter(&dbf->db_mtx); 190 if (dbf->db_state != DB_EVICTING) { 191 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 192 return (dbf); 193 } 194 mutex_exit(&dbf->db_mtx); 195 } 196 } 197 198 mutex_enter(&db->db_mtx); 199 db->db_hash_next = h->hash_table[idx]; 200 h->hash_table[idx] = db; 201 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 202 atomic_inc_64(&dbuf_hash_count); 203 204 return (NULL); 205 } 206 207 /* 208 * Remove an entry from the hash table. It must be in the EVICTING state. 209 */ 210 static void 211 dbuf_hash_remove(dmu_buf_impl_t *db) 212 { 213 dbuf_hash_table_t *h = &dbuf_hash_table; 214 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object, 215 db->db_level, db->db_blkid); 216 uint64_t idx = hv & h->hash_table_mask; 217 dmu_buf_impl_t *dbf, **dbp; 218 219 /* 220 * We musn't hold db_mtx to maintain lock ordering: 221 * DBUF_HASH_MUTEX > db_mtx. 222 */ 223 ASSERT(refcount_is_zero(&db->db_holds)); 224 ASSERT(db->db_state == DB_EVICTING); 225 ASSERT(!MUTEX_HELD(&db->db_mtx)); 226 227 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 228 dbp = &h->hash_table[idx]; 229 while ((dbf = *dbp) != db) { 230 dbp = &dbf->db_hash_next; 231 ASSERT(dbf != NULL); 232 } 233 *dbp = db->db_hash_next; 234 db->db_hash_next = NULL; 235 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 236 atomic_dec_64(&dbuf_hash_count); 237 } 238 239 static arc_evict_func_t dbuf_do_evict; 240 241 typedef enum { 242 DBVU_EVICTING, 243 DBVU_NOT_EVICTING 244 } dbvu_verify_type_t; 245 246 static void 247 dbuf_verify_user(dmu_buf_impl_t *db, dbvu_verify_type_t verify_type) 248 { 249 #ifdef ZFS_DEBUG 250 int64_t holds; 251 252 if (db->db_user == NULL) 253 return; 254 255 /* Only data blocks support the attachment of user data. */ 256 ASSERT(db->db_level == 0); 257 258 /* Clients must resolve a dbuf before attaching user data. */ 259 ASSERT(db->db.db_data != NULL); 260 ASSERT3U(db->db_state, ==, DB_CACHED); 261 262 holds = refcount_count(&db->db_holds); 263 if (verify_type == DBVU_EVICTING) { 264 /* 265 * Immediate eviction occurs when holds == dirtycnt. 266 * For normal eviction buffers, holds is zero on 267 * eviction, except when dbuf_fix_old_data() calls 268 * dbuf_clear_data(). However, the hold count can grow 269 * during eviction even though db_mtx is held (see 270 * dmu_bonus_hold() for an example), so we can only 271 * test the generic invariant that holds >= dirtycnt. 272 */ 273 ASSERT3U(holds, >=, db->db_dirtycnt); 274 } else { 275 if (db->db_user_immediate_evict == TRUE) 276 ASSERT3U(holds, >=, db->db_dirtycnt); 277 else 278 ASSERT3U(holds, >, 0); 279 } 280 #endif 281 } 282 283 static void 284 dbuf_evict_user(dmu_buf_impl_t *db) 285 { 286 dmu_buf_user_t *dbu = db->db_user; 287 288 ASSERT(MUTEX_HELD(&db->db_mtx)); 289 290 if (dbu == NULL) 291 return; 292 293 dbuf_verify_user(db, DBVU_EVICTING); 294 db->db_user = NULL; 295 296 #ifdef ZFS_DEBUG 297 if (dbu->dbu_clear_on_evict_dbufp != NULL) 298 *dbu->dbu_clear_on_evict_dbufp = NULL; 299 #endif 300 301 /* 302 * Invoke the callback from a taskq to avoid lock order reversals 303 * and limit stack depth. 304 */ 305 taskq_dispatch_ent(dbu_evict_taskq, dbu->dbu_evict_func, dbu, 0, 306 &dbu->dbu_tqent); 307 } 308 309 boolean_t 310 dbuf_is_metadata(dmu_buf_impl_t *db) 311 { 312 if (db->db_level > 0) { 313 return (B_TRUE); 314 } else { 315 boolean_t is_metadata; 316 317 DB_DNODE_ENTER(db); 318 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type); 319 DB_DNODE_EXIT(db); 320 321 return (is_metadata); 322 } 323 } 324 325 void 326 dbuf_evict(dmu_buf_impl_t *db) 327 { 328 ASSERT(MUTEX_HELD(&db->db_mtx)); 329 ASSERT(db->db_buf == NULL); 330 ASSERT(db->db_data_pending == NULL); 331 332 dbuf_clear(db); 333 dbuf_destroy(db); 334 } 335 336 void 337 dbuf_init(void) 338 { 339 uint64_t hsize = 1ULL << 16; 340 dbuf_hash_table_t *h = &dbuf_hash_table; 341 int i; 342 343 /* 344 * The hash table is big enough to fill all of physical memory 345 * with an average 4K block size. The table will take up 346 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers). 347 */ 348 while (hsize * 4096 < physmem * PAGESIZE) 349 hsize <<= 1; 350 351 retry: 352 h->hash_table_mask = hsize - 1; 353 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP); 354 if (h->hash_table == NULL) { 355 /* XXX - we should really return an error instead of assert */ 356 ASSERT(hsize > (1ULL << 10)); 357 hsize >>= 1; 358 goto retry; 359 } 360 361 dbuf_cache = kmem_cache_create("dmu_buf_impl_t", 362 sizeof (dmu_buf_impl_t), 363 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0); 364 365 for (i = 0; i < DBUF_MUTEXES; i++) 366 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL); 367 368 /* 369 * All entries are queued via taskq_dispatch_ent(), so min/maxalloc 370 * configuration is not required. 371 */ 372 dbu_evict_taskq = taskq_create("dbu_evict", 1, minclsyspri, 0, 0, 0); 373 } 374 375 void 376 dbuf_fini(void) 377 { 378 dbuf_hash_table_t *h = &dbuf_hash_table; 379 int i; 380 381 for (i = 0; i < DBUF_MUTEXES; i++) 382 mutex_destroy(&h->hash_mutexes[i]); 383 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *)); 384 kmem_cache_destroy(dbuf_cache); 385 taskq_destroy(dbu_evict_taskq); 386 } 387 388 /* 389 * Other stuff. 390 */ 391 392 #ifdef ZFS_DEBUG 393 static void 394 dbuf_verify(dmu_buf_impl_t *db) 395 { 396 dnode_t *dn; 397 dbuf_dirty_record_t *dr; 398 399 ASSERT(MUTEX_HELD(&db->db_mtx)); 400 401 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY)) 402 return; 403 404 ASSERT(db->db_objset != NULL); 405 DB_DNODE_ENTER(db); 406 dn = DB_DNODE(db); 407 if (dn == NULL) { 408 ASSERT(db->db_parent == NULL); 409 ASSERT(db->db_blkptr == NULL); 410 } else { 411 ASSERT3U(db->db.db_object, ==, dn->dn_object); 412 ASSERT3P(db->db_objset, ==, dn->dn_objset); 413 ASSERT3U(db->db_level, <, dn->dn_nlevels); 414 ASSERT(db->db_blkid == DMU_BONUS_BLKID || 415 db->db_blkid == DMU_SPILL_BLKID || 416 !avl_is_empty(&dn->dn_dbufs)); 417 } 418 if (db->db_blkid == DMU_BONUS_BLKID) { 419 ASSERT(dn != NULL); 420 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 421 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID); 422 } else if (db->db_blkid == DMU_SPILL_BLKID) { 423 ASSERT(dn != NULL); 424 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 425 ASSERT0(db->db.db_offset); 426 } else { 427 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size); 428 } 429 430 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next) 431 ASSERT(dr->dr_dbuf == db); 432 433 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next) 434 ASSERT(dr->dr_dbuf == db); 435 436 /* 437 * We can't assert that db_size matches dn_datablksz because it 438 * can be momentarily different when another thread is doing 439 * dnode_set_blksz(). 440 */ 441 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) { 442 dr = db->db_data_pending; 443 /* 444 * It should only be modified in syncing context, so 445 * make sure we only have one copy of the data. 446 */ 447 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf); 448 } 449 450 /* verify db->db_blkptr */ 451 if (db->db_blkptr) { 452 if (db->db_parent == dn->dn_dbuf) { 453 /* db is pointed to by the dnode */ 454 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */ 455 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object)) 456 ASSERT(db->db_parent == NULL); 457 else 458 ASSERT(db->db_parent != NULL); 459 if (db->db_blkid != DMU_SPILL_BLKID) 460 ASSERT3P(db->db_blkptr, ==, 461 &dn->dn_phys->dn_blkptr[db->db_blkid]); 462 } else { 463 /* db is pointed to by an indirect block */ 464 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT; 465 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1); 466 ASSERT3U(db->db_parent->db.db_object, ==, 467 db->db.db_object); 468 /* 469 * dnode_grow_indblksz() can make this fail if we don't 470 * have the struct_rwlock. XXX indblksz no longer 471 * grows. safe to do this now? 472 */ 473 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 474 ASSERT3P(db->db_blkptr, ==, 475 ((blkptr_t *)db->db_parent->db.db_data + 476 db->db_blkid % epb)); 477 } 478 } 479 } 480 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) && 481 (db->db_buf == NULL || db->db_buf->b_data) && 482 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID && 483 db->db_state != DB_FILL && !dn->dn_free_txg) { 484 /* 485 * If the blkptr isn't set but they have nonzero data, 486 * it had better be dirty, otherwise we'll lose that 487 * data when we evict this buffer. 488 */ 489 if (db->db_dirtycnt == 0) { 490 uint64_t *buf = db->db.db_data; 491 int i; 492 493 for (i = 0; i < db->db.db_size >> 3; i++) { 494 ASSERT(buf[i] == 0); 495 } 496 } 497 } 498 DB_DNODE_EXIT(db); 499 } 500 #endif 501 502 static void 503 dbuf_clear_data(dmu_buf_impl_t *db) 504 { 505 ASSERT(MUTEX_HELD(&db->db_mtx)); 506 dbuf_evict_user(db); 507 db->db_buf = NULL; 508 db->db.db_data = NULL; 509 if (db->db_state != DB_NOFILL) 510 db->db_state = DB_UNCACHED; 511 } 512 513 static void 514 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf) 515 { 516 ASSERT(MUTEX_HELD(&db->db_mtx)); 517 ASSERT(buf != NULL); 518 519 db->db_buf = buf; 520 ASSERT(buf->b_data != NULL); 521 db->db.db_data = buf->b_data; 522 if (!arc_released(buf)) 523 arc_set_callback(buf, dbuf_do_evict, db); 524 } 525 526 /* 527 * Loan out an arc_buf for read. Return the loaned arc_buf. 528 */ 529 arc_buf_t * 530 dbuf_loan_arcbuf(dmu_buf_impl_t *db) 531 { 532 arc_buf_t *abuf; 533 534 mutex_enter(&db->db_mtx); 535 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) { 536 int blksz = db->db.db_size; 537 spa_t *spa = db->db_objset->os_spa; 538 539 mutex_exit(&db->db_mtx); 540 abuf = arc_loan_buf(spa, blksz); 541 bcopy(db->db.db_data, abuf->b_data, blksz); 542 } else { 543 abuf = db->db_buf; 544 arc_loan_inuse_buf(abuf, db); 545 dbuf_clear_data(db); 546 mutex_exit(&db->db_mtx); 547 } 548 return (abuf); 549 } 550 551 /* 552 * Calculate which level n block references the data at the level 0 offset 553 * provided. 554 */ 555 uint64_t 556 dbuf_whichblock(dnode_t *dn, int64_t level, uint64_t offset) 557 { 558 if (dn->dn_datablkshift != 0 && dn->dn_indblkshift != 0) { 559 /* 560 * The level n blkid is equal to the level 0 blkid divided by 561 * the number of level 0s in a level n block. 562 * 563 * The level 0 blkid is offset >> datablkshift = 564 * offset / 2^datablkshift. 565 * 566 * The number of level 0s in a level n is the number of block 567 * pointers in an indirect block, raised to the power of level. 568 * This is 2^(indblkshift - SPA_BLKPTRSHIFT)^level = 569 * 2^(level*(indblkshift - SPA_BLKPTRSHIFT)). 570 * 571 * Thus, the level n blkid is: offset / 572 * ((2^datablkshift)*(2^(level*(indblkshift - SPA_BLKPTRSHIFT))) 573 * = offset / 2^(datablkshift + level * 574 * (indblkshift - SPA_BLKPTRSHIFT)) 575 * = offset >> (datablkshift + level * 576 * (indblkshift - SPA_BLKPTRSHIFT)) 577 */ 578 return (offset >> (dn->dn_datablkshift + level * 579 (dn->dn_indblkshift - SPA_BLKPTRSHIFT))); 580 } else { 581 ASSERT3U(offset, <, dn->dn_datablksz); 582 return (0); 583 } 584 } 585 586 static void 587 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb) 588 { 589 dmu_buf_impl_t *db = vdb; 590 591 mutex_enter(&db->db_mtx); 592 ASSERT3U(db->db_state, ==, DB_READ); 593 /* 594 * All reads are synchronous, so we must have a hold on the dbuf 595 */ 596 ASSERT(refcount_count(&db->db_holds) > 0); 597 ASSERT(db->db_buf == NULL); 598 ASSERT(db->db.db_data == NULL); 599 if (db->db_level == 0 && db->db_freed_in_flight) { 600 /* we were freed in flight; disregard any error */ 601 arc_release(buf, db); 602 bzero(buf->b_data, db->db.db_size); 603 arc_buf_freeze(buf); 604 db->db_freed_in_flight = FALSE; 605 dbuf_set_data(db, buf); 606 db->db_state = DB_CACHED; 607 } else if (zio == NULL || zio->io_error == 0) { 608 dbuf_set_data(db, buf); 609 db->db_state = DB_CACHED; 610 } else { 611 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 612 ASSERT3P(db->db_buf, ==, NULL); 613 VERIFY(arc_buf_remove_ref(buf, db)); 614 db->db_state = DB_UNCACHED; 615 } 616 cv_broadcast(&db->db_changed); 617 dbuf_rele_and_unlock(db, NULL); 618 } 619 620 static void 621 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) 622 { 623 dnode_t *dn; 624 zbookmark_phys_t zb; 625 arc_flags_t aflags = ARC_FLAG_NOWAIT; 626 627 DB_DNODE_ENTER(db); 628 dn = DB_DNODE(db); 629 ASSERT(!refcount_is_zero(&db->db_holds)); 630 /* We need the struct_rwlock to prevent db_blkptr from changing. */ 631 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 632 ASSERT(MUTEX_HELD(&db->db_mtx)); 633 ASSERT(db->db_state == DB_UNCACHED); 634 ASSERT(db->db_buf == NULL); 635 636 if (db->db_blkid == DMU_BONUS_BLKID) { 637 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen); 638 639 ASSERT3U(bonuslen, <=, db->db.db_size); 640 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN); 641 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 642 if (bonuslen < DN_MAX_BONUSLEN) 643 bzero(db->db.db_data, DN_MAX_BONUSLEN); 644 if (bonuslen) 645 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen); 646 DB_DNODE_EXIT(db); 647 db->db_state = DB_CACHED; 648 mutex_exit(&db->db_mtx); 649 return; 650 } 651 652 /* 653 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync() 654 * processes the delete record and clears the bp while we are waiting 655 * for the dn_mtx (resulting in a "no" from block_freed). 656 */ 657 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) || 658 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) || 659 BP_IS_HOLE(db->db_blkptr)))) { 660 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 661 662 DB_DNODE_EXIT(db); 663 dbuf_set_data(db, arc_buf_alloc(db->db_objset->os_spa, 664 db->db.db_size, db, type)); 665 bzero(db->db.db_data, db->db.db_size); 666 db->db_state = DB_CACHED; 667 mutex_exit(&db->db_mtx); 668 return; 669 } 670 671 DB_DNODE_EXIT(db); 672 673 db->db_state = DB_READ; 674 mutex_exit(&db->db_mtx); 675 676 if (DBUF_IS_L2CACHEABLE(db)) 677 aflags |= ARC_FLAG_L2CACHE; 678 if (DBUF_IS_L2COMPRESSIBLE(db)) 679 aflags |= ARC_FLAG_L2COMPRESS; 680 681 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ? 682 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET, 683 db->db.db_object, db->db_level, db->db_blkid); 684 685 dbuf_add_ref(db, NULL); 686 687 (void) arc_read(zio, db->db_objset->os_spa, db->db_blkptr, 688 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ, 689 (flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED, 690 &aflags, &zb); 691 } 692 693 int 694 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) 695 { 696 int err = 0; 697 boolean_t havepzio = (zio != NULL); 698 boolean_t prefetch; 699 dnode_t *dn; 700 701 /* 702 * We don't have to hold the mutex to check db_state because it 703 * can't be freed while we have a hold on the buffer. 704 */ 705 ASSERT(!refcount_is_zero(&db->db_holds)); 706 707 if (db->db_state == DB_NOFILL) 708 return (SET_ERROR(EIO)); 709 710 DB_DNODE_ENTER(db); 711 dn = DB_DNODE(db); 712 if ((flags & DB_RF_HAVESTRUCT) == 0) 713 rw_enter(&dn->dn_struct_rwlock, RW_READER); 714 715 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 716 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL && 717 DBUF_IS_CACHEABLE(db); 718 719 mutex_enter(&db->db_mtx); 720 if (db->db_state == DB_CACHED) { 721 mutex_exit(&db->db_mtx); 722 if (prefetch) 723 dmu_zfetch(&dn->dn_zfetch, db->db_blkid, 1); 724 if ((flags & DB_RF_HAVESTRUCT) == 0) 725 rw_exit(&dn->dn_struct_rwlock); 726 DB_DNODE_EXIT(db); 727 } else if (db->db_state == DB_UNCACHED) { 728 spa_t *spa = dn->dn_objset->os_spa; 729 730 if (zio == NULL) 731 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL); 732 dbuf_read_impl(db, zio, flags); 733 734 /* dbuf_read_impl has dropped db_mtx for us */ 735 736 if (prefetch) 737 dmu_zfetch(&dn->dn_zfetch, db->db_blkid, 1); 738 739 if ((flags & DB_RF_HAVESTRUCT) == 0) 740 rw_exit(&dn->dn_struct_rwlock); 741 DB_DNODE_EXIT(db); 742 743 if (!havepzio) 744 err = zio_wait(zio); 745 } else { 746 /* 747 * Another reader came in while the dbuf was in flight 748 * between UNCACHED and CACHED. Either a writer will finish 749 * writing the buffer (sending the dbuf to CACHED) or the 750 * first reader's request will reach the read_done callback 751 * and send the dbuf to CACHED. Otherwise, a failure 752 * occurred and the dbuf went to UNCACHED. 753 */ 754 mutex_exit(&db->db_mtx); 755 if (prefetch) 756 dmu_zfetch(&dn->dn_zfetch, db->db_blkid, 1); 757 if ((flags & DB_RF_HAVESTRUCT) == 0) 758 rw_exit(&dn->dn_struct_rwlock); 759 DB_DNODE_EXIT(db); 760 761 /* Skip the wait per the caller's request. */ 762 mutex_enter(&db->db_mtx); 763 if ((flags & DB_RF_NEVERWAIT) == 0) { 764 while (db->db_state == DB_READ || 765 db->db_state == DB_FILL) { 766 ASSERT(db->db_state == DB_READ || 767 (flags & DB_RF_HAVESTRUCT) == 0); 768 DTRACE_PROBE2(blocked__read, dmu_buf_impl_t *, 769 db, zio_t *, zio); 770 cv_wait(&db->db_changed, &db->db_mtx); 771 } 772 if (db->db_state == DB_UNCACHED) 773 err = SET_ERROR(EIO); 774 } 775 mutex_exit(&db->db_mtx); 776 } 777 778 ASSERT(err || havepzio || db->db_state == DB_CACHED); 779 return (err); 780 } 781 782 static void 783 dbuf_noread(dmu_buf_impl_t *db) 784 { 785 ASSERT(!refcount_is_zero(&db->db_holds)); 786 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 787 mutex_enter(&db->db_mtx); 788 while (db->db_state == DB_READ || db->db_state == DB_FILL) 789 cv_wait(&db->db_changed, &db->db_mtx); 790 if (db->db_state == DB_UNCACHED) { 791 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 792 spa_t *spa = db->db_objset->os_spa; 793 794 ASSERT(db->db_buf == NULL); 795 ASSERT(db->db.db_data == NULL); 796 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type)); 797 db->db_state = DB_FILL; 798 } else if (db->db_state == DB_NOFILL) { 799 dbuf_clear_data(db); 800 } else { 801 ASSERT3U(db->db_state, ==, DB_CACHED); 802 } 803 mutex_exit(&db->db_mtx); 804 } 805 806 /* 807 * This is our just-in-time copy function. It makes a copy of 808 * buffers, that have been modified in a previous transaction 809 * group, before we modify them in the current active group. 810 * 811 * This function is used in two places: when we are dirtying a 812 * buffer for the first time in a txg, and when we are freeing 813 * a range in a dnode that includes this buffer. 814 * 815 * Note that when we are called from dbuf_free_range() we do 816 * not put a hold on the buffer, we just traverse the active 817 * dbuf list for the dnode. 818 */ 819 static void 820 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg) 821 { 822 dbuf_dirty_record_t *dr = db->db_last_dirty; 823 824 ASSERT(MUTEX_HELD(&db->db_mtx)); 825 ASSERT(db->db.db_data != NULL); 826 ASSERT(db->db_level == 0); 827 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT); 828 829 if (dr == NULL || 830 (dr->dt.dl.dr_data != 831 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf))) 832 return; 833 834 /* 835 * If the last dirty record for this dbuf has not yet synced 836 * and its referencing the dbuf data, either: 837 * reset the reference to point to a new copy, 838 * or (if there a no active holders) 839 * just null out the current db_data pointer. 840 */ 841 ASSERT(dr->dr_txg >= txg - 2); 842 if (db->db_blkid == DMU_BONUS_BLKID) { 843 /* Note that the data bufs here are zio_bufs */ 844 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN); 845 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 846 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN); 847 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) { 848 int size = db->db.db_size; 849 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 850 spa_t *spa = db->db_objset->os_spa; 851 852 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type); 853 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size); 854 } else { 855 dbuf_clear_data(db); 856 } 857 } 858 859 void 860 dbuf_unoverride(dbuf_dirty_record_t *dr) 861 { 862 dmu_buf_impl_t *db = dr->dr_dbuf; 863 blkptr_t *bp = &dr->dt.dl.dr_overridden_by; 864 uint64_t txg = dr->dr_txg; 865 866 ASSERT(MUTEX_HELD(&db->db_mtx)); 867 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC); 868 ASSERT(db->db_level == 0); 869 870 if (db->db_blkid == DMU_BONUS_BLKID || 871 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN) 872 return; 873 874 ASSERT(db->db_data_pending != dr); 875 876 /* free this block */ 877 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite) 878 zio_free(db->db_objset->os_spa, txg, bp); 879 880 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 881 dr->dt.dl.dr_nopwrite = B_FALSE; 882 883 /* 884 * Release the already-written buffer, so we leave it in 885 * a consistent dirty state. Note that all callers are 886 * modifying the buffer, so they will immediately do 887 * another (redundant) arc_release(). Therefore, leave 888 * the buf thawed to save the effort of freezing & 889 * immediately re-thawing it. 890 */ 891 arc_release(dr->dt.dl.dr_data, db); 892 } 893 894 /* 895 * Evict (if its unreferenced) or clear (if its referenced) any level-0 896 * data blocks in the free range, so that any future readers will find 897 * empty blocks. 898 * 899 * This is a no-op if the dataset is in the middle of an incremental 900 * receive; see comment below for details. 901 */ 902 void 903 dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, 904 dmu_tx_t *tx) 905 { 906 dmu_buf_impl_t db_search; 907 dmu_buf_impl_t *db, *db_next; 908 uint64_t txg = tx->tx_txg; 909 avl_index_t where; 910 911 if (end_blkid > dn->dn_maxblkid && (end_blkid != DMU_SPILL_BLKID)) 912 end_blkid = dn->dn_maxblkid; 913 dprintf_dnode(dn, "start=%llu end=%llu\n", start_blkid, end_blkid); 914 915 db_search.db_level = 0; 916 db_search.db_blkid = start_blkid; 917 db_search.db_state = DB_SEARCH; 918 919 mutex_enter(&dn->dn_dbufs_mtx); 920 if (start_blkid >= dn->dn_unlisted_l0_blkid) { 921 /* There can't be any dbufs in this range; no need to search. */ 922 #ifdef DEBUG 923 db = avl_find(&dn->dn_dbufs, &db_search, &where); 924 ASSERT3P(db, ==, NULL); 925 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 926 ASSERT(db == NULL || db->db_level > 0); 927 #endif 928 mutex_exit(&dn->dn_dbufs_mtx); 929 return; 930 } else if (dmu_objset_is_receiving(dn->dn_objset)) { 931 /* 932 * If we are receiving, we expect there to be no dbufs in 933 * the range to be freed, because receive modifies each 934 * block at most once, and in offset order. If this is 935 * not the case, it can lead to performance problems, 936 * so note that we unexpectedly took the slow path. 937 */ 938 atomic_inc_64(&zfs_free_range_recv_miss); 939 } 940 941 db = avl_find(&dn->dn_dbufs, &db_search, &where); 942 ASSERT3P(db, ==, NULL); 943 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 944 945 for (; db != NULL; db = db_next) { 946 db_next = AVL_NEXT(&dn->dn_dbufs, db); 947 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 948 949 if (db->db_level != 0 || db->db_blkid > end_blkid) { 950 break; 951 } 952 ASSERT3U(db->db_blkid, >=, start_blkid); 953 954 /* found a level 0 buffer in the range */ 955 mutex_enter(&db->db_mtx); 956 if (dbuf_undirty(db, tx)) { 957 /* mutex has been dropped and dbuf destroyed */ 958 continue; 959 } 960 961 if (db->db_state == DB_UNCACHED || 962 db->db_state == DB_NOFILL || 963 db->db_state == DB_EVICTING) { 964 ASSERT(db->db.db_data == NULL); 965 mutex_exit(&db->db_mtx); 966 continue; 967 } 968 if (db->db_state == DB_READ || db->db_state == DB_FILL) { 969 /* will be handled in dbuf_read_done or dbuf_rele */ 970 db->db_freed_in_flight = TRUE; 971 mutex_exit(&db->db_mtx); 972 continue; 973 } 974 if (refcount_count(&db->db_holds) == 0) { 975 ASSERT(db->db_buf); 976 dbuf_clear(db); 977 continue; 978 } 979 /* The dbuf is referenced */ 980 981 if (db->db_last_dirty != NULL) { 982 dbuf_dirty_record_t *dr = db->db_last_dirty; 983 984 if (dr->dr_txg == txg) { 985 /* 986 * This buffer is "in-use", re-adjust the file 987 * size to reflect that this buffer may 988 * contain new data when we sync. 989 */ 990 if (db->db_blkid != DMU_SPILL_BLKID && 991 db->db_blkid > dn->dn_maxblkid) 992 dn->dn_maxblkid = db->db_blkid; 993 dbuf_unoverride(dr); 994 } else { 995 /* 996 * This dbuf is not dirty in the open context. 997 * Either uncache it (if its not referenced in 998 * the open context) or reset its contents to 999 * empty. 1000 */ 1001 dbuf_fix_old_data(db, txg); 1002 } 1003 } 1004 /* clear the contents if its cached */ 1005 if (db->db_state == DB_CACHED) { 1006 ASSERT(db->db.db_data != NULL); 1007 arc_release(db->db_buf, db); 1008 bzero(db->db.db_data, db->db.db_size); 1009 arc_buf_freeze(db->db_buf); 1010 } 1011 1012 mutex_exit(&db->db_mtx); 1013 } 1014 mutex_exit(&dn->dn_dbufs_mtx); 1015 } 1016 1017 static int 1018 dbuf_block_freeable(dmu_buf_impl_t *db) 1019 { 1020 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset; 1021 uint64_t birth_txg = 0; 1022 1023 /* 1024 * We don't need any locking to protect db_blkptr: 1025 * If it's syncing, then db_last_dirty will be set 1026 * so we'll ignore db_blkptr. 1027 * 1028 * This logic ensures that only block births for 1029 * filled blocks are considered. 1030 */ 1031 ASSERT(MUTEX_HELD(&db->db_mtx)); 1032 if (db->db_last_dirty && (db->db_blkptr == NULL || 1033 !BP_IS_HOLE(db->db_blkptr))) { 1034 birth_txg = db->db_last_dirty->dr_txg; 1035 } else if (db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr)) { 1036 birth_txg = db->db_blkptr->blk_birth; 1037 } 1038 1039 /* 1040 * If this block don't exist or is in a snapshot, it can't be freed. 1041 * Don't pass the bp to dsl_dataset_block_freeable() since we 1042 * are holding the db_mtx lock and might deadlock if we are 1043 * prefetching a dedup-ed block. 1044 */ 1045 if (birth_txg != 0) 1046 return (ds == NULL || 1047 dsl_dataset_block_freeable(ds, NULL, birth_txg)); 1048 else 1049 return (B_FALSE); 1050 } 1051 1052 void 1053 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx) 1054 { 1055 arc_buf_t *buf, *obuf; 1056 int osize = db->db.db_size; 1057 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 1058 dnode_t *dn; 1059 1060 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1061 1062 DB_DNODE_ENTER(db); 1063 dn = DB_DNODE(db); 1064 1065 /* XXX does *this* func really need the lock? */ 1066 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 1067 1068 /* 1069 * This call to dmu_buf_will_dirty() with the dn_struct_rwlock held 1070 * is OK, because there can be no other references to the db 1071 * when we are changing its size, so no concurrent DB_FILL can 1072 * be happening. 1073 */ 1074 /* 1075 * XXX we should be doing a dbuf_read, checking the return 1076 * value and returning that up to our callers 1077 */ 1078 dmu_buf_will_dirty(&db->db, tx); 1079 1080 /* create the data buffer for the new block */ 1081 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type); 1082 1083 /* copy old block data to the new block */ 1084 obuf = db->db_buf; 1085 bcopy(obuf->b_data, buf->b_data, MIN(osize, size)); 1086 /* zero the remainder */ 1087 if (size > osize) 1088 bzero((uint8_t *)buf->b_data + osize, size - osize); 1089 1090 mutex_enter(&db->db_mtx); 1091 dbuf_set_data(db, buf); 1092 VERIFY(arc_buf_remove_ref(obuf, db)); 1093 db->db.db_size = size; 1094 1095 if (db->db_level == 0) { 1096 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 1097 db->db_last_dirty->dt.dl.dr_data = buf; 1098 } 1099 mutex_exit(&db->db_mtx); 1100 1101 dnode_willuse_space(dn, size-osize, tx); 1102 DB_DNODE_EXIT(db); 1103 } 1104 1105 void 1106 dbuf_release_bp(dmu_buf_impl_t *db) 1107 { 1108 objset_t *os = db->db_objset; 1109 1110 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os))); 1111 ASSERT(arc_released(os->os_phys_buf) || 1112 list_link_active(&os->os_dsl_dataset->ds_synced_link)); 1113 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf)); 1114 1115 (void) arc_release(db->db_buf, db); 1116 } 1117 1118 /* 1119 * We already have a dirty record for this TXG, and we are being 1120 * dirtied again. 1121 */ 1122 static void 1123 dbuf_redirty(dbuf_dirty_record_t *dr) 1124 { 1125 dmu_buf_impl_t *db = dr->dr_dbuf; 1126 1127 ASSERT(MUTEX_HELD(&db->db_mtx)); 1128 1129 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) { 1130 /* 1131 * If this buffer has already been written out, 1132 * we now need to reset its state. 1133 */ 1134 dbuf_unoverride(dr); 1135 if (db->db.db_object != DMU_META_DNODE_OBJECT && 1136 db->db_state != DB_NOFILL) { 1137 /* Already released on initial dirty, so just thaw. */ 1138 ASSERT(arc_released(db->db_buf)); 1139 arc_buf_thaw(db->db_buf); 1140 } 1141 } 1142 } 1143 1144 dbuf_dirty_record_t * 1145 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1146 { 1147 dnode_t *dn; 1148 objset_t *os; 1149 dbuf_dirty_record_t **drp, *dr; 1150 int drop_struct_lock = FALSE; 1151 boolean_t do_free_accounting = B_FALSE; 1152 int txgoff = tx->tx_txg & TXG_MASK; 1153 1154 ASSERT(tx->tx_txg != 0); 1155 ASSERT(!refcount_is_zero(&db->db_holds)); 1156 DMU_TX_DIRTY_BUF(tx, db); 1157 1158 DB_DNODE_ENTER(db); 1159 dn = DB_DNODE(db); 1160 /* 1161 * Shouldn't dirty a regular buffer in syncing context. Private 1162 * objects may be dirtied in syncing context, but only if they 1163 * were already pre-dirtied in open context. 1164 */ 1165 ASSERT(!dmu_tx_is_syncing(tx) || 1166 BP_IS_HOLE(dn->dn_objset->os_rootbp) || 1167 DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1168 dn->dn_objset->os_dsl_dataset == NULL); 1169 /* 1170 * We make this assert for private objects as well, but after we 1171 * check if we're already dirty. They are allowed to re-dirty 1172 * in syncing context. 1173 */ 1174 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1175 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1176 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1177 1178 mutex_enter(&db->db_mtx); 1179 /* 1180 * XXX make this true for indirects too? The problem is that 1181 * transactions created with dmu_tx_create_assigned() from 1182 * syncing context don't bother holding ahead. 1183 */ 1184 ASSERT(db->db_level != 0 || 1185 db->db_state == DB_CACHED || db->db_state == DB_FILL || 1186 db->db_state == DB_NOFILL); 1187 1188 mutex_enter(&dn->dn_mtx); 1189 /* 1190 * Don't set dirtyctx to SYNC if we're just modifying this as we 1191 * initialize the objset. 1192 */ 1193 if (dn->dn_dirtyctx == DN_UNDIRTIED && 1194 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) { 1195 dn->dn_dirtyctx = 1196 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN); 1197 ASSERT(dn->dn_dirtyctx_firstset == NULL); 1198 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP); 1199 } 1200 mutex_exit(&dn->dn_mtx); 1201 1202 if (db->db_blkid == DMU_SPILL_BLKID) 1203 dn->dn_have_spill = B_TRUE; 1204 1205 /* 1206 * If this buffer is already dirty, we're done. 1207 */ 1208 drp = &db->db_last_dirty; 1209 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg || 1210 db->db.db_object == DMU_META_DNODE_OBJECT); 1211 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg) 1212 drp = &dr->dr_next; 1213 if (dr && dr->dr_txg == tx->tx_txg) { 1214 DB_DNODE_EXIT(db); 1215 1216 dbuf_redirty(dr); 1217 mutex_exit(&db->db_mtx); 1218 return (dr); 1219 } 1220 1221 /* 1222 * Only valid if not already dirty. 1223 */ 1224 ASSERT(dn->dn_object == 0 || 1225 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1226 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1227 1228 ASSERT3U(dn->dn_nlevels, >, db->db_level); 1229 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) || 1230 dn->dn_phys->dn_nlevels > db->db_level || 1231 dn->dn_next_nlevels[txgoff] > db->db_level || 1232 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level || 1233 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level); 1234 1235 /* 1236 * We should only be dirtying in syncing context if it's the 1237 * mos or we're initializing the os or it's a special object. 1238 * However, we are allowed to dirty in syncing context provided 1239 * we already dirtied it in open context. Hence we must make 1240 * this assertion only if we're not already dirty. 1241 */ 1242 os = dn->dn_objset; 1243 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1244 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp)); 1245 ASSERT(db->db.db_size != 0); 1246 1247 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1248 1249 if (db->db_blkid != DMU_BONUS_BLKID) { 1250 /* 1251 * Update the accounting. 1252 * Note: we delay "free accounting" until after we drop 1253 * the db_mtx. This keeps us from grabbing other locks 1254 * (and possibly deadlocking) in bp_get_dsize() while 1255 * also holding the db_mtx. 1256 */ 1257 dnode_willuse_space(dn, db->db.db_size, tx); 1258 do_free_accounting = dbuf_block_freeable(db); 1259 } 1260 1261 /* 1262 * If this buffer is dirty in an old transaction group we need 1263 * to make a copy of it so that the changes we make in this 1264 * transaction group won't leak out when we sync the older txg. 1265 */ 1266 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP); 1267 if (db->db_level == 0) { 1268 void *data_old = db->db_buf; 1269 1270 if (db->db_state != DB_NOFILL) { 1271 if (db->db_blkid == DMU_BONUS_BLKID) { 1272 dbuf_fix_old_data(db, tx->tx_txg); 1273 data_old = db->db.db_data; 1274 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) { 1275 /* 1276 * Release the data buffer from the cache so 1277 * that we can modify it without impacting 1278 * possible other users of this cached data 1279 * block. Note that indirect blocks and 1280 * private objects are not released until the 1281 * syncing state (since they are only modified 1282 * then). 1283 */ 1284 arc_release(db->db_buf, db); 1285 dbuf_fix_old_data(db, tx->tx_txg); 1286 data_old = db->db_buf; 1287 } 1288 ASSERT(data_old != NULL); 1289 } 1290 dr->dt.dl.dr_data = data_old; 1291 } else { 1292 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL); 1293 list_create(&dr->dt.di.dr_children, 1294 sizeof (dbuf_dirty_record_t), 1295 offsetof(dbuf_dirty_record_t, dr_dirty_node)); 1296 } 1297 if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL) 1298 dr->dr_accounted = db->db.db_size; 1299 dr->dr_dbuf = db; 1300 dr->dr_txg = tx->tx_txg; 1301 dr->dr_next = *drp; 1302 *drp = dr; 1303 1304 /* 1305 * We could have been freed_in_flight between the dbuf_noread 1306 * and dbuf_dirty. We win, as though the dbuf_noread() had 1307 * happened after the free. 1308 */ 1309 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1310 db->db_blkid != DMU_SPILL_BLKID) { 1311 mutex_enter(&dn->dn_mtx); 1312 if (dn->dn_free_ranges[txgoff] != NULL) { 1313 range_tree_clear(dn->dn_free_ranges[txgoff], 1314 db->db_blkid, 1); 1315 } 1316 mutex_exit(&dn->dn_mtx); 1317 db->db_freed_in_flight = FALSE; 1318 } 1319 1320 /* 1321 * This buffer is now part of this txg 1322 */ 1323 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg); 1324 db->db_dirtycnt += 1; 1325 ASSERT3U(db->db_dirtycnt, <=, 3); 1326 1327 mutex_exit(&db->db_mtx); 1328 1329 if (db->db_blkid == DMU_BONUS_BLKID || 1330 db->db_blkid == DMU_SPILL_BLKID) { 1331 mutex_enter(&dn->dn_mtx); 1332 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1333 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1334 mutex_exit(&dn->dn_mtx); 1335 dnode_setdirty(dn, tx); 1336 DB_DNODE_EXIT(db); 1337 return (dr); 1338 } else if (do_free_accounting) { 1339 blkptr_t *bp = db->db_blkptr; 1340 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ? 1341 bp_get_dsize(os->os_spa, bp) : db->db.db_size; 1342 /* 1343 * This is only a guess -- if the dbuf is dirty 1344 * in a previous txg, we don't know how much 1345 * space it will use on disk yet. We should 1346 * really have the struct_rwlock to access 1347 * db_blkptr, but since this is just a guess, 1348 * it's OK if we get an odd answer. 1349 */ 1350 ddt_prefetch(os->os_spa, bp); 1351 dnode_willuse_space(dn, -willfree, tx); 1352 } 1353 1354 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 1355 rw_enter(&dn->dn_struct_rwlock, RW_READER); 1356 drop_struct_lock = TRUE; 1357 } 1358 1359 if (db->db_level == 0) { 1360 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock); 1361 ASSERT(dn->dn_maxblkid >= db->db_blkid); 1362 } 1363 1364 if (db->db_level+1 < dn->dn_nlevels) { 1365 dmu_buf_impl_t *parent = db->db_parent; 1366 dbuf_dirty_record_t *di; 1367 int parent_held = FALSE; 1368 1369 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) { 1370 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1371 1372 parent = dbuf_hold_level(dn, db->db_level+1, 1373 db->db_blkid >> epbs, FTAG); 1374 ASSERT(parent != NULL); 1375 parent_held = TRUE; 1376 } 1377 if (drop_struct_lock) 1378 rw_exit(&dn->dn_struct_rwlock); 1379 ASSERT3U(db->db_level+1, ==, parent->db_level); 1380 di = dbuf_dirty(parent, tx); 1381 if (parent_held) 1382 dbuf_rele(parent, FTAG); 1383 1384 mutex_enter(&db->db_mtx); 1385 /* 1386 * Since we've dropped the mutex, it's possible that 1387 * dbuf_undirty() might have changed this out from under us. 1388 */ 1389 if (db->db_last_dirty == dr || 1390 dn->dn_object == DMU_META_DNODE_OBJECT) { 1391 mutex_enter(&di->dt.di.dr_mtx); 1392 ASSERT3U(di->dr_txg, ==, tx->tx_txg); 1393 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1394 list_insert_tail(&di->dt.di.dr_children, dr); 1395 mutex_exit(&di->dt.di.dr_mtx); 1396 dr->dr_parent = di; 1397 } 1398 mutex_exit(&db->db_mtx); 1399 } else { 1400 ASSERT(db->db_level+1 == dn->dn_nlevels); 1401 ASSERT(db->db_blkid < dn->dn_nblkptr); 1402 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf); 1403 mutex_enter(&dn->dn_mtx); 1404 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1405 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1406 mutex_exit(&dn->dn_mtx); 1407 if (drop_struct_lock) 1408 rw_exit(&dn->dn_struct_rwlock); 1409 } 1410 1411 dnode_setdirty(dn, tx); 1412 DB_DNODE_EXIT(db); 1413 return (dr); 1414 } 1415 1416 /* 1417 * Undirty a buffer in the transaction group referenced by the given 1418 * transaction. Return whether this evicted the dbuf. 1419 */ 1420 static boolean_t 1421 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1422 { 1423 dnode_t *dn; 1424 uint64_t txg = tx->tx_txg; 1425 dbuf_dirty_record_t *dr, **drp; 1426 1427 ASSERT(txg != 0); 1428 1429 /* 1430 * Due to our use of dn_nlevels below, this can only be called 1431 * in open context, unless we are operating on the MOS. 1432 * From syncing context, dn_nlevels may be different from the 1433 * dn_nlevels used when dbuf was dirtied. 1434 */ 1435 ASSERT(db->db_objset == 1436 dmu_objset_pool(db->db_objset)->dp_meta_objset || 1437 txg != spa_syncing_txg(dmu_objset_spa(db->db_objset))); 1438 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1439 ASSERT0(db->db_level); 1440 ASSERT(MUTEX_HELD(&db->db_mtx)); 1441 1442 /* 1443 * If this buffer is not dirty, we're done. 1444 */ 1445 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next) 1446 if (dr->dr_txg <= txg) 1447 break; 1448 if (dr == NULL || dr->dr_txg < txg) 1449 return (B_FALSE); 1450 ASSERT(dr->dr_txg == txg); 1451 ASSERT(dr->dr_dbuf == db); 1452 1453 DB_DNODE_ENTER(db); 1454 dn = DB_DNODE(db); 1455 1456 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1457 1458 ASSERT(db->db.db_size != 0); 1459 1460 dsl_pool_undirty_space(dmu_objset_pool(dn->dn_objset), 1461 dr->dr_accounted, txg); 1462 1463 *drp = dr->dr_next; 1464 1465 /* 1466 * Note that there are three places in dbuf_dirty() 1467 * where this dirty record may be put on a list. 1468 * Make sure to do a list_remove corresponding to 1469 * every one of those list_insert calls. 1470 */ 1471 if (dr->dr_parent) { 1472 mutex_enter(&dr->dr_parent->dt.di.dr_mtx); 1473 list_remove(&dr->dr_parent->dt.di.dr_children, dr); 1474 mutex_exit(&dr->dr_parent->dt.di.dr_mtx); 1475 } else if (db->db_blkid == DMU_SPILL_BLKID || 1476 db->db_level + 1 == dn->dn_nlevels) { 1477 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf); 1478 mutex_enter(&dn->dn_mtx); 1479 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr); 1480 mutex_exit(&dn->dn_mtx); 1481 } 1482 DB_DNODE_EXIT(db); 1483 1484 if (db->db_state != DB_NOFILL) { 1485 dbuf_unoverride(dr); 1486 1487 ASSERT(db->db_buf != NULL); 1488 ASSERT(dr->dt.dl.dr_data != NULL); 1489 if (dr->dt.dl.dr_data != db->db_buf) 1490 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db)); 1491 } 1492 1493 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 1494 1495 ASSERT(db->db_dirtycnt > 0); 1496 db->db_dirtycnt -= 1; 1497 1498 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) { 1499 arc_buf_t *buf = db->db_buf; 1500 1501 ASSERT(db->db_state == DB_NOFILL || arc_released(buf)); 1502 dbuf_clear_data(db); 1503 VERIFY(arc_buf_remove_ref(buf, db)); 1504 dbuf_evict(db); 1505 return (B_TRUE); 1506 } 1507 1508 return (B_FALSE); 1509 } 1510 1511 void 1512 dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx) 1513 { 1514 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1515 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH; 1516 1517 ASSERT(tx->tx_txg != 0); 1518 ASSERT(!refcount_is_zero(&db->db_holds)); 1519 1520 /* 1521 * Quick check for dirtyness. For already dirty blocks, this 1522 * reduces runtime of this function by >90%, and overall performance 1523 * by 50% for some workloads (e.g. file deletion with indirect blocks 1524 * cached). 1525 */ 1526 mutex_enter(&db->db_mtx); 1527 dbuf_dirty_record_t *dr; 1528 for (dr = db->db_last_dirty; 1529 dr != NULL && dr->dr_txg >= tx->tx_txg; dr = dr->dr_next) { 1530 /* 1531 * It's possible that it is already dirty but not cached, 1532 * because there are some calls to dbuf_dirty() that don't 1533 * go through dmu_buf_will_dirty(). 1534 */ 1535 if (dr->dr_txg == tx->tx_txg && db->db_state == DB_CACHED) { 1536 /* This dbuf is already dirty and cached. */ 1537 dbuf_redirty(dr); 1538 mutex_exit(&db->db_mtx); 1539 return; 1540 } 1541 } 1542 mutex_exit(&db->db_mtx); 1543 1544 DB_DNODE_ENTER(db); 1545 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock)) 1546 rf |= DB_RF_HAVESTRUCT; 1547 DB_DNODE_EXIT(db); 1548 (void) dbuf_read(db, NULL, rf); 1549 (void) dbuf_dirty(db, tx); 1550 } 1551 1552 void 1553 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1554 { 1555 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1556 1557 db->db_state = DB_NOFILL; 1558 1559 dmu_buf_will_fill(db_fake, tx); 1560 } 1561 1562 void 1563 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1564 { 1565 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1566 1567 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1568 ASSERT(tx->tx_txg != 0); 1569 ASSERT(db->db_level == 0); 1570 ASSERT(!refcount_is_zero(&db->db_holds)); 1571 1572 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT || 1573 dmu_tx_private_ok(tx)); 1574 1575 dbuf_noread(db); 1576 (void) dbuf_dirty(db, tx); 1577 } 1578 1579 #pragma weak dmu_buf_fill_done = dbuf_fill_done 1580 /* ARGSUSED */ 1581 void 1582 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx) 1583 { 1584 mutex_enter(&db->db_mtx); 1585 DBUF_VERIFY(db); 1586 1587 if (db->db_state == DB_FILL) { 1588 if (db->db_level == 0 && db->db_freed_in_flight) { 1589 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1590 /* we were freed while filling */ 1591 /* XXX dbuf_undirty? */ 1592 bzero(db->db.db_data, db->db.db_size); 1593 db->db_freed_in_flight = FALSE; 1594 } 1595 db->db_state = DB_CACHED; 1596 cv_broadcast(&db->db_changed); 1597 } 1598 mutex_exit(&db->db_mtx); 1599 } 1600 1601 void 1602 dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data, 1603 bp_embedded_type_t etype, enum zio_compress comp, 1604 int uncompressed_size, int compressed_size, int byteorder, 1605 dmu_tx_t *tx) 1606 { 1607 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 1608 struct dirty_leaf *dl; 1609 dmu_object_type_t type; 1610 1611 if (etype == BP_EMBEDDED_TYPE_DATA) { 1612 ASSERT(spa_feature_is_active(dmu_objset_spa(db->db_objset), 1613 SPA_FEATURE_EMBEDDED_DATA)); 1614 } 1615 1616 DB_DNODE_ENTER(db); 1617 type = DB_DNODE(db)->dn_type; 1618 DB_DNODE_EXIT(db); 1619 1620 ASSERT0(db->db_level); 1621 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1622 1623 dmu_buf_will_not_fill(dbuf, tx); 1624 1625 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 1626 dl = &db->db_last_dirty->dt.dl; 1627 encode_embedded_bp_compressed(&dl->dr_overridden_by, 1628 data, comp, uncompressed_size, compressed_size); 1629 BPE_SET_ETYPE(&dl->dr_overridden_by, etype); 1630 BP_SET_TYPE(&dl->dr_overridden_by, type); 1631 BP_SET_LEVEL(&dl->dr_overridden_by, 0); 1632 BP_SET_BYTEORDER(&dl->dr_overridden_by, byteorder); 1633 1634 dl->dr_override_state = DR_OVERRIDDEN; 1635 dl->dr_overridden_by.blk_birth = db->db_last_dirty->dr_txg; 1636 } 1637 1638 /* 1639 * Directly assign a provided arc buf to a given dbuf if it's not referenced 1640 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf. 1641 */ 1642 void 1643 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx) 1644 { 1645 ASSERT(!refcount_is_zero(&db->db_holds)); 1646 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1647 ASSERT(db->db_level == 0); 1648 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA); 1649 ASSERT(buf != NULL); 1650 ASSERT(arc_buf_size(buf) == db->db.db_size); 1651 ASSERT(tx->tx_txg != 0); 1652 1653 arc_return_buf(buf, db); 1654 ASSERT(arc_released(buf)); 1655 1656 mutex_enter(&db->db_mtx); 1657 1658 while (db->db_state == DB_READ || db->db_state == DB_FILL) 1659 cv_wait(&db->db_changed, &db->db_mtx); 1660 1661 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED); 1662 1663 if (db->db_state == DB_CACHED && 1664 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) { 1665 mutex_exit(&db->db_mtx); 1666 (void) dbuf_dirty(db, tx); 1667 bcopy(buf->b_data, db->db.db_data, db->db.db_size); 1668 VERIFY(arc_buf_remove_ref(buf, db)); 1669 xuio_stat_wbuf_copied(); 1670 return; 1671 } 1672 1673 xuio_stat_wbuf_nocopy(); 1674 if (db->db_state == DB_CACHED) { 1675 dbuf_dirty_record_t *dr = db->db_last_dirty; 1676 1677 ASSERT(db->db_buf != NULL); 1678 if (dr != NULL && dr->dr_txg == tx->tx_txg) { 1679 ASSERT(dr->dt.dl.dr_data == db->db_buf); 1680 if (!arc_released(db->db_buf)) { 1681 ASSERT(dr->dt.dl.dr_override_state == 1682 DR_OVERRIDDEN); 1683 arc_release(db->db_buf, db); 1684 } 1685 dr->dt.dl.dr_data = buf; 1686 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1687 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) { 1688 arc_release(db->db_buf, db); 1689 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1690 } 1691 db->db_buf = NULL; 1692 } 1693 ASSERT(db->db_buf == NULL); 1694 dbuf_set_data(db, buf); 1695 db->db_state = DB_FILL; 1696 mutex_exit(&db->db_mtx); 1697 (void) dbuf_dirty(db, tx); 1698 dmu_buf_fill_done(&db->db, tx); 1699 } 1700 1701 /* 1702 * "Clear" the contents of this dbuf. This will mark the dbuf 1703 * EVICTING and clear *most* of its references. Unfortunately, 1704 * when we are not holding the dn_dbufs_mtx, we can't clear the 1705 * entry in the dn_dbufs list. We have to wait until dbuf_destroy() 1706 * in this case. For callers from the DMU we will usually see: 1707 * dbuf_clear()->arc_clear_callback()->dbuf_do_evict()->dbuf_destroy() 1708 * For the arc callback, we will usually see: 1709 * dbuf_do_evict()->dbuf_clear();dbuf_destroy() 1710 * Sometimes, though, we will get a mix of these two: 1711 * DMU: dbuf_clear()->arc_clear_callback() 1712 * ARC: dbuf_do_evict()->dbuf_destroy() 1713 * 1714 * This routine will dissociate the dbuf from the arc, by calling 1715 * arc_clear_callback(), but will not evict the data from the ARC. 1716 */ 1717 void 1718 dbuf_clear(dmu_buf_impl_t *db) 1719 { 1720 dnode_t *dn; 1721 dmu_buf_impl_t *parent = db->db_parent; 1722 dmu_buf_impl_t *dndb; 1723 boolean_t dbuf_gone = B_FALSE; 1724 1725 ASSERT(MUTEX_HELD(&db->db_mtx)); 1726 ASSERT(refcount_is_zero(&db->db_holds)); 1727 1728 dbuf_evict_user(db); 1729 1730 if (db->db_state == DB_CACHED) { 1731 ASSERT(db->db.db_data != NULL); 1732 if (db->db_blkid == DMU_BONUS_BLKID) { 1733 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN); 1734 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 1735 } 1736 db->db.db_data = NULL; 1737 db->db_state = DB_UNCACHED; 1738 } 1739 1740 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL); 1741 ASSERT(db->db_data_pending == NULL); 1742 1743 db->db_state = DB_EVICTING; 1744 db->db_blkptr = NULL; 1745 1746 DB_DNODE_ENTER(db); 1747 dn = DB_DNODE(db); 1748 dndb = dn->dn_dbuf; 1749 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) { 1750 avl_remove(&dn->dn_dbufs, db); 1751 atomic_dec_32(&dn->dn_dbufs_count); 1752 membar_producer(); 1753 DB_DNODE_EXIT(db); 1754 /* 1755 * Decrementing the dbuf count means that the hold corresponding 1756 * to the removed dbuf is no longer discounted in dnode_move(), 1757 * so the dnode cannot be moved until after we release the hold. 1758 * The membar_producer() ensures visibility of the decremented 1759 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually 1760 * release any lock. 1761 */ 1762 dnode_rele(dn, db); 1763 db->db_dnode_handle = NULL; 1764 } else { 1765 DB_DNODE_EXIT(db); 1766 } 1767 1768 if (db->db_buf) 1769 dbuf_gone = arc_clear_callback(db->db_buf); 1770 1771 if (!dbuf_gone) 1772 mutex_exit(&db->db_mtx); 1773 1774 /* 1775 * If this dbuf is referenced from an indirect dbuf, 1776 * decrement the ref count on the indirect dbuf. 1777 */ 1778 if (parent && parent != dndb) 1779 dbuf_rele(parent, db); 1780 } 1781 1782 /* 1783 * Note: While bpp will always be updated if the function returns success, 1784 * parentp will not be updated if the dnode does not have dn_dbuf filled in; 1785 * this happens when the dnode is the meta-dnode, or a userused or groupused 1786 * object. 1787 */ 1788 static int 1789 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, 1790 dmu_buf_impl_t **parentp, blkptr_t **bpp) 1791 { 1792 int nlevels, epbs; 1793 1794 *parentp = NULL; 1795 *bpp = NULL; 1796 1797 ASSERT(blkid != DMU_BONUS_BLKID); 1798 1799 if (blkid == DMU_SPILL_BLKID) { 1800 mutex_enter(&dn->dn_mtx); 1801 if (dn->dn_have_spill && 1802 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) 1803 *bpp = &dn->dn_phys->dn_spill; 1804 else 1805 *bpp = NULL; 1806 dbuf_add_ref(dn->dn_dbuf, NULL); 1807 *parentp = dn->dn_dbuf; 1808 mutex_exit(&dn->dn_mtx); 1809 return (0); 1810 } 1811 1812 if (dn->dn_phys->dn_nlevels == 0) 1813 nlevels = 1; 1814 else 1815 nlevels = dn->dn_phys->dn_nlevels; 1816 1817 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1818 1819 ASSERT3U(level * epbs, <, 64); 1820 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1821 if (level >= nlevels || 1822 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) { 1823 /* the buffer has no parent yet */ 1824 return (SET_ERROR(ENOENT)); 1825 } else if (level < nlevels-1) { 1826 /* this block is referenced from an indirect block */ 1827 int err = dbuf_hold_impl(dn, level+1, 1828 blkid >> epbs, fail_sparse, FALSE, NULL, parentp); 1829 if (err) 1830 return (err); 1831 err = dbuf_read(*parentp, NULL, 1832 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL)); 1833 if (err) { 1834 dbuf_rele(*parentp, NULL); 1835 *parentp = NULL; 1836 return (err); 1837 } 1838 *bpp = ((blkptr_t *)(*parentp)->db.db_data) + 1839 (blkid & ((1ULL << epbs) - 1)); 1840 return (0); 1841 } else { 1842 /* the block is referenced from the dnode */ 1843 ASSERT3U(level, ==, nlevels-1); 1844 ASSERT(dn->dn_phys->dn_nblkptr == 0 || 1845 blkid < dn->dn_phys->dn_nblkptr); 1846 if (dn->dn_dbuf) { 1847 dbuf_add_ref(dn->dn_dbuf, NULL); 1848 *parentp = dn->dn_dbuf; 1849 } 1850 *bpp = &dn->dn_phys->dn_blkptr[blkid]; 1851 return (0); 1852 } 1853 } 1854 1855 static dmu_buf_impl_t * 1856 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid, 1857 dmu_buf_impl_t *parent, blkptr_t *blkptr) 1858 { 1859 objset_t *os = dn->dn_objset; 1860 dmu_buf_impl_t *db, *odb; 1861 1862 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1863 ASSERT(dn->dn_type != DMU_OT_NONE); 1864 1865 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP); 1866 1867 db->db_objset = os; 1868 db->db.db_object = dn->dn_object; 1869 db->db_level = level; 1870 db->db_blkid = blkid; 1871 db->db_last_dirty = NULL; 1872 db->db_dirtycnt = 0; 1873 db->db_dnode_handle = dn->dn_handle; 1874 db->db_parent = parent; 1875 db->db_blkptr = blkptr; 1876 1877 db->db_user = NULL; 1878 db->db_user_immediate_evict = FALSE; 1879 db->db_freed_in_flight = FALSE; 1880 db->db_pending_evict = FALSE; 1881 1882 if (blkid == DMU_BONUS_BLKID) { 1883 ASSERT3P(parent, ==, dn->dn_dbuf); 1884 db->db.db_size = DN_MAX_BONUSLEN - 1885 (dn->dn_nblkptr-1) * sizeof (blkptr_t); 1886 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 1887 db->db.db_offset = DMU_BONUS_BLKID; 1888 db->db_state = DB_UNCACHED; 1889 /* the bonus dbuf is not placed in the hash table */ 1890 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1891 return (db); 1892 } else if (blkid == DMU_SPILL_BLKID) { 1893 db->db.db_size = (blkptr != NULL) ? 1894 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE; 1895 db->db.db_offset = 0; 1896 } else { 1897 int blocksize = 1898 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz; 1899 db->db.db_size = blocksize; 1900 db->db.db_offset = db->db_blkid * blocksize; 1901 } 1902 1903 /* 1904 * Hold the dn_dbufs_mtx while we get the new dbuf 1905 * in the hash table *and* added to the dbufs list. 1906 * This prevents a possible deadlock with someone 1907 * trying to look up this dbuf before its added to the 1908 * dn_dbufs list. 1909 */ 1910 mutex_enter(&dn->dn_dbufs_mtx); 1911 db->db_state = DB_EVICTING; 1912 if ((odb = dbuf_hash_insert(db)) != NULL) { 1913 /* someone else inserted it first */ 1914 kmem_cache_free(dbuf_cache, db); 1915 mutex_exit(&dn->dn_dbufs_mtx); 1916 return (odb); 1917 } 1918 avl_add(&dn->dn_dbufs, db); 1919 if (db->db_level == 0 && db->db_blkid >= 1920 dn->dn_unlisted_l0_blkid) 1921 dn->dn_unlisted_l0_blkid = db->db_blkid + 1; 1922 db->db_state = DB_UNCACHED; 1923 mutex_exit(&dn->dn_dbufs_mtx); 1924 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1925 1926 if (parent && parent != dn->dn_dbuf) 1927 dbuf_add_ref(parent, db); 1928 1929 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1930 refcount_count(&dn->dn_holds) > 0); 1931 (void) refcount_add(&dn->dn_holds, db); 1932 atomic_inc_32(&dn->dn_dbufs_count); 1933 1934 dprintf_dbuf(db, "db=%p\n", db); 1935 1936 return (db); 1937 } 1938 1939 static int 1940 dbuf_do_evict(void *private) 1941 { 1942 dmu_buf_impl_t *db = private; 1943 1944 if (!MUTEX_HELD(&db->db_mtx)) 1945 mutex_enter(&db->db_mtx); 1946 1947 ASSERT(refcount_is_zero(&db->db_holds)); 1948 1949 if (db->db_state != DB_EVICTING) { 1950 ASSERT(db->db_state == DB_CACHED); 1951 DBUF_VERIFY(db); 1952 db->db_buf = NULL; 1953 dbuf_evict(db); 1954 } else { 1955 mutex_exit(&db->db_mtx); 1956 dbuf_destroy(db); 1957 } 1958 return (0); 1959 } 1960 1961 static void 1962 dbuf_destroy(dmu_buf_impl_t *db) 1963 { 1964 ASSERT(refcount_is_zero(&db->db_holds)); 1965 1966 if (db->db_blkid != DMU_BONUS_BLKID) { 1967 /* 1968 * If this dbuf is still on the dn_dbufs list, 1969 * remove it from that list. 1970 */ 1971 if (db->db_dnode_handle != NULL) { 1972 dnode_t *dn; 1973 1974 DB_DNODE_ENTER(db); 1975 dn = DB_DNODE(db); 1976 mutex_enter(&dn->dn_dbufs_mtx); 1977 avl_remove(&dn->dn_dbufs, db); 1978 atomic_dec_32(&dn->dn_dbufs_count); 1979 mutex_exit(&dn->dn_dbufs_mtx); 1980 DB_DNODE_EXIT(db); 1981 /* 1982 * Decrementing the dbuf count means that the hold 1983 * corresponding to the removed dbuf is no longer 1984 * discounted in dnode_move(), so the dnode cannot be 1985 * moved until after we release the hold. 1986 */ 1987 dnode_rele(dn, db); 1988 db->db_dnode_handle = NULL; 1989 } 1990 dbuf_hash_remove(db); 1991 } 1992 db->db_parent = NULL; 1993 db->db_buf = NULL; 1994 1995 ASSERT(db->db.db_data == NULL); 1996 ASSERT(db->db_hash_next == NULL); 1997 ASSERT(db->db_blkptr == NULL); 1998 ASSERT(db->db_data_pending == NULL); 1999 2000 kmem_cache_free(dbuf_cache, db); 2001 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 2002 } 2003 2004 typedef struct dbuf_prefetch_arg { 2005 spa_t *dpa_spa; /* The spa to issue the prefetch in. */ 2006 zbookmark_phys_t dpa_zb; /* The target block to prefetch. */ 2007 int dpa_epbs; /* Entries (blkptr_t's) Per Block Shift. */ 2008 int dpa_curlevel; /* The current level that we're reading */ 2009 zio_priority_t dpa_prio; /* The priority I/Os should be issued at. */ 2010 zio_t *dpa_zio; /* The parent zio_t for all prefetches. */ 2011 arc_flags_t dpa_aflags; /* Flags to pass to the final prefetch. */ 2012 } dbuf_prefetch_arg_t; 2013 2014 /* 2015 * Actually issue the prefetch read for the block given. 2016 */ 2017 static void 2018 dbuf_issue_final_prefetch(dbuf_prefetch_arg_t *dpa, blkptr_t *bp) 2019 { 2020 if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) 2021 return; 2022 2023 arc_flags_t aflags = 2024 dpa->dpa_aflags | ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH; 2025 2026 ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); 2027 ASSERT3U(dpa->dpa_curlevel, ==, dpa->dpa_zb.zb_level); 2028 ASSERT(dpa->dpa_zio != NULL); 2029 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, bp, NULL, NULL, 2030 dpa->dpa_prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2031 &aflags, &dpa->dpa_zb); 2032 } 2033 2034 /* 2035 * Called when an indirect block above our prefetch target is read in. This 2036 * will either read in the next indirect block down the tree or issue the actual 2037 * prefetch if the next block down is our target. 2038 */ 2039 static void 2040 dbuf_prefetch_indirect_done(zio_t *zio, arc_buf_t *abuf, void *private) 2041 { 2042 dbuf_prefetch_arg_t *dpa = private; 2043 2044 ASSERT3S(dpa->dpa_zb.zb_level, <, dpa->dpa_curlevel); 2045 ASSERT3S(dpa->dpa_curlevel, >, 0); 2046 if (zio != NULL) { 2047 ASSERT3S(BP_GET_LEVEL(zio->io_bp), ==, dpa->dpa_curlevel); 2048 ASSERT3U(BP_GET_LSIZE(zio->io_bp), ==, zio->io_size); 2049 ASSERT3P(zio->io_spa, ==, dpa->dpa_spa); 2050 } 2051 2052 dpa->dpa_curlevel--; 2053 2054 uint64_t nextblkid = dpa->dpa_zb.zb_blkid >> 2055 (dpa->dpa_epbs * (dpa->dpa_curlevel - dpa->dpa_zb.zb_level)); 2056 blkptr_t *bp = ((blkptr_t *)abuf->b_data) + 2057 P2PHASE(nextblkid, 1ULL << dpa->dpa_epbs); 2058 if (BP_IS_HOLE(bp) || (zio != NULL && zio->io_error != 0)) { 2059 kmem_free(dpa, sizeof (*dpa)); 2060 } else if (dpa->dpa_curlevel == dpa->dpa_zb.zb_level) { 2061 ASSERT3U(nextblkid, ==, dpa->dpa_zb.zb_blkid); 2062 dbuf_issue_final_prefetch(dpa, bp); 2063 kmem_free(dpa, sizeof (*dpa)); 2064 } else { 2065 arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; 2066 zbookmark_phys_t zb; 2067 2068 ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); 2069 2070 SET_BOOKMARK(&zb, dpa->dpa_zb.zb_objset, 2071 dpa->dpa_zb.zb_object, dpa->dpa_curlevel, nextblkid); 2072 2073 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, 2074 bp, dbuf_prefetch_indirect_done, dpa, dpa->dpa_prio, 2075 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2076 &iter_aflags, &zb); 2077 } 2078 (void) arc_buf_remove_ref(abuf, private); 2079 } 2080 2081 /* 2082 * Issue prefetch reads for the given block on the given level. If the indirect 2083 * blocks above that block are not in memory, we will read them in 2084 * asynchronously. As a result, this call never blocks waiting for a read to 2085 * complete. 2086 */ 2087 void 2088 dbuf_prefetch(dnode_t *dn, int64_t level, uint64_t blkid, zio_priority_t prio, 2089 arc_flags_t aflags) 2090 { 2091 blkptr_t bp; 2092 int epbs, nlevels, curlevel; 2093 uint64_t curblkid; 2094 2095 ASSERT(blkid != DMU_BONUS_BLKID); 2096 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 2097 2098 if (blkid > dn->dn_maxblkid) 2099 return; 2100 2101 if (dnode_block_freed(dn, blkid)) 2102 return; 2103 2104 /* 2105 * This dnode hasn't been written to disk yet, so there's nothing to 2106 * prefetch. 2107 */ 2108 nlevels = dn->dn_phys->dn_nlevels; 2109 if (level >= nlevels || dn->dn_phys->dn_nblkptr == 0) 2110 return; 2111 2112 epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2113 if (dn->dn_phys->dn_maxblkid < blkid << (epbs * level)) 2114 return; 2115 2116 dmu_buf_impl_t *db = dbuf_find(dn->dn_objset, dn->dn_object, 2117 level, blkid); 2118 if (db != NULL) { 2119 mutex_exit(&db->db_mtx); 2120 /* 2121 * This dbuf already exists. It is either CACHED, or 2122 * (we assume) about to be read or filled. 2123 */ 2124 return; 2125 } 2126 2127 /* 2128 * Find the closest ancestor (indirect block) of the target block 2129 * that is present in the cache. In this indirect block, we will 2130 * find the bp that is at curlevel, curblkid. 2131 */ 2132 curlevel = level; 2133 curblkid = blkid; 2134 while (curlevel < nlevels - 1) { 2135 int parent_level = curlevel + 1; 2136 uint64_t parent_blkid = curblkid >> epbs; 2137 dmu_buf_impl_t *db; 2138 2139 if (dbuf_hold_impl(dn, parent_level, parent_blkid, 2140 FALSE, TRUE, FTAG, &db) == 0) { 2141 blkptr_t *bpp = db->db_buf->b_data; 2142 bp = bpp[P2PHASE(curblkid, 1 << epbs)]; 2143 dbuf_rele(db, FTAG); 2144 break; 2145 } 2146 2147 curlevel = parent_level; 2148 curblkid = parent_blkid; 2149 } 2150 2151 if (curlevel == nlevels - 1) { 2152 /* No cached indirect blocks found. */ 2153 ASSERT3U(curblkid, <, dn->dn_phys->dn_nblkptr); 2154 bp = dn->dn_phys->dn_blkptr[curblkid]; 2155 } 2156 if (BP_IS_HOLE(&bp)) 2157 return; 2158 2159 ASSERT3U(curlevel, ==, BP_GET_LEVEL(&bp)); 2160 2161 zio_t *pio = zio_root(dmu_objset_spa(dn->dn_objset), NULL, NULL, 2162 ZIO_FLAG_CANFAIL); 2163 2164 dbuf_prefetch_arg_t *dpa = kmem_zalloc(sizeof (*dpa), KM_SLEEP); 2165 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; 2166 SET_BOOKMARK(&dpa->dpa_zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, 2167 dn->dn_object, level, blkid); 2168 dpa->dpa_curlevel = curlevel; 2169 dpa->dpa_prio = prio; 2170 dpa->dpa_aflags = aflags; 2171 dpa->dpa_spa = dn->dn_objset->os_spa; 2172 dpa->dpa_epbs = epbs; 2173 dpa->dpa_zio = pio; 2174 2175 /* 2176 * If we have the indirect just above us, no need to do the asynchronous 2177 * prefetch chain; we'll just run the last step ourselves. If we're at 2178 * a higher level, though, we want to issue the prefetches for all the 2179 * indirect blocks asynchronously, so we can go on with whatever we were 2180 * doing. 2181 */ 2182 if (curlevel == level) { 2183 ASSERT3U(curblkid, ==, blkid); 2184 dbuf_issue_final_prefetch(dpa, &bp); 2185 kmem_free(dpa, sizeof (*dpa)); 2186 } else { 2187 arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; 2188 zbookmark_phys_t zb; 2189 2190 SET_BOOKMARK(&zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, 2191 dn->dn_object, curlevel, curblkid); 2192 (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, 2193 &bp, dbuf_prefetch_indirect_done, dpa, prio, 2194 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 2195 &iter_aflags, &zb); 2196 } 2197 /* 2198 * We use pio here instead of dpa_zio since it's possible that 2199 * dpa may have already been freed. 2200 */ 2201 zio_nowait(pio); 2202 } 2203 2204 /* 2205 * Returns with db_holds incremented, and db_mtx not held. 2206 * Note: dn_struct_rwlock must be held. 2207 */ 2208 int 2209 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, 2210 boolean_t fail_sparse, boolean_t fail_uncached, 2211 void *tag, dmu_buf_impl_t **dbp) 2212 { 2213 dmu_buf_impl_t *db, *parent = NULL; 2214 2215 ASSERT(blkid != DMU_BONUS_BLKID); 2216 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 2217 ASSERT3U(dn->dn_nlevels, >, level); 2218 2219 *dbp = NULL; 2220 top: 2221 /* dbuf_find() returns with db_mtx held */ 2222 db = dbuf_find(dn->dn_objset, dn->dn_object, level, blkid); 2223 2224 if (db == NULL) { 2225 blkptr_t *bp = NULL; 2226 int err; 2227 2228 if (fail_uncached) 2229 return (SET_ERROR(ENOENT)); 2230 2231 ASSERT3P(parent, ==, NULL); 2232 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp); 2233 if (fail_sparse) { 2234 if (err == 0 && bp && BP_IS_HOLE(bp)) 2235 err = SET_ERROR(ENOENT); 2236 if (err) { 2237 if (parent) 2238 dbuf_rele(parent, NULL); 2239 return (err); 2240 } 2241 } 2242 if (err && err != ENOENT) 2243 return (err); 2244 db = dbuf_create(dn, level, blkid, parent, bp); 2245 } 2246 2247 if (fail_uncached && db->db_state != DB_CACHED) { 2248 mutex_exit(&db->db_mtx); 2249 return (SET_ERROR(ENOENT)); 2250 } 2251 2252 if (db->db_buf && refcount_is_zero(&db->db_holds)) { 2253 arc_buf_add_ref(db->db_buf, db); 2254 if (db->db_buf->b_data == NULL) { 2255 dbuf_clear(db); 2256 if (parent) { 2257 dbuf_rele(parent, NULL); 2258 parent = NULL; 2259 } 2260 goto top; 2261 } 2262 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data); 2263 } 2264 2265 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf)); 2266 2267 /* 2268 * If this buffer is currently syncing out, and we are are 2269 * still referencing it from db_data, we need to make a copy 2270 * of it in case we decide we want to dirty it again in this txg. 2271 */ 2272 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 2273 dn->dn_object != DMU_META_DNODE_OBJECT && 2274 db->db_state == DB_CACHED && db->db_data_pending) { 2275 dbuf_dirty_record_t *dr = db->db_data_pending; 2276 2277 if (dr->dt.dl.dr_data == db->db_buf) { 2278 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2279 2280 dbuf_set_data(db, 2281 arc_buf_alloc(dn->dn_objset->os_spa, 2282 db->db.db_size, db, type)); 2283 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data, 2284 db->db.db_size); 2285 } 2286 } 2287 2288 (void) refcount_add(&db->db_holds, tag); 2289 DBUF_VERIFY(db); 2290 mutex_exit(&db->db_mtx); 2291 2292 /* NOTE: we can't rele the parent until after we drop the db_mtx */ 2293 if (parent) 2294 dbuf_rele(parent, NULL); 2295 2296 ASSERT3P(DB_DNODE(db), ==, dn); 2297 ASSERT3U(db->db_blkid, ==, blkid); 2298 ASSERT3U(db->db_level, ==, level); 2299 *dbp = db; 2300 2301 return (0); 2302 } 2303 2304 dmu_buf_impl_t * 2305 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag) 2306 { 2307 return (dbuf_hold_level(dn, 0, blkid, tag)); 2308 } 2309 2310 dmu_buf_impl_t * 2311 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag) 2312 { 2313 dmu_buf_impl_t *db; 2314 int err = dbuf_hold_impl(dn, level, blkid, FALSE, FALSE, tag, &db); 2315 return (err ? NULL : db); 2316 } 2317 2318 void 2319 dbuf_create_bonus(dnode_t *dn) 2320 { 2321 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 2322 2323 ASSERT(dn->dn_bonus == NULL); 2324 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL); 2325 } 2326 2327 int 2328 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx) 2329 { 2330 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2331 dnode_t *dn; 2332 2333 if (db->db_blkid != DMU_SPILL_BLKID) 2334 return (SET_ERROR(ENOTSUP)); 2335 if (blksz == 0) 2336 blksz = SPA_MINBLOCKSIZE; 2337 ASSERT3U(blksz, <=, spa_maxblocksize(dmu_objset_spa(db->db_objset))); 2338 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE); 2339 2340 DB_DNODE_ENTER(db); 2341 dn = DB_DNODE(db); 2342 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 2343 dbuf_new_size(db, blksz, tx); 2344 rw_exit(&dn->dn_struct_rwlock); 2345 DB_DNODE_EXIT(db); 2346 2347 return (0); 2348 } 2349 2350 void 2351 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx) 2352 { 2353 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx); 2354 } 2355 2356 #pragma weak dmu_buf_add_ref = dbuf_add_ref 2357 void 2358 dbuf_add_ref(dmu_buf_impl_t *db, void *tag) 2359 { 2360 int64_t holds = refcount_add(&db->db_holds, tag); 2361 ASSERT(holds > 1); 2362 } 2363 2364 #pragma weak dmu_buf_try_add_ref = dbuf_try_add_ref 2365 boolean_t 2366 dbuf_try_add_ref(dmu_buf_t *db_fake, objset_t *os, uint64_t obj, uint64_t blkid, 2367 void *tag) 2368 { 2369 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2370 dmu_buf_impl_t *found_db; 2371 boolean_t result = B_FALSE; 2372 2373 if (db->db_blkid == DMU_BONUS_BLKID) 2374 found_db = dbuf_find_bonus(os, obj); 2375 else 2376 found_db = dbuf_find(os, obj, 0, blkid); 2377 2378 if (found_db != NULL) { 2379 if (db == found_db && dbuf_refcount(db) > db->db_dirtycnt) { 2380 (void) refcount_add(&db->db_holds, tag); 2381 result = B_TRUE; 2382 } 2383 mutex_exit(&db->db_mtx); 2384 } 2385 return (result); 2386 } 2387 2388 /* 2389 * If you call dbuf_rele() you had better not be referencing the dnode handle 2390 * unless you have some other direct or indirect hold on the dnode. (An indirect 2391 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.) 2392 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the 2393 * dnode's parent dbuf evicting its dnode handles. 2394 */ 2395 void 2396 dbuf_rele(dmu_buf_impl_t *db, void *tag) 2397 { 2398 mutex_enter(&db->db_mtx); 2399 dbuf_rele_and_unlock(db, tag); 2400 } 2401 2402 void 2403 dmu_buf_rele(dmu_buf_t *db, void *tag) 2404 { 2405 dbuf_rele((dmu_buf_impl_t *)db, tag); 2406 } 2407 2408 /* 2409 * dbuf_rele() for an already-locked dbuf. This is necessary to allow 2410 * db_dirtycnt and db_holds to be updated atomically. 2411 */ 2412 void 2413 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) 2414 { 2415 int64_t holds; 2416 2417 ASSERT(MUTEX_HELD(&db->db_mtx)); 2418 DBUF_VERIFY(db); 2419 2420 /* 2421 * Remove the reference to the dbuf before removing its hold on the 2422 * dnode so we can guarantee in dnode_move() that a referenced bonus 2423 * buffer has a corresponding dnode hold. 2424 */ 2425 holds = refcount_remove(&db->db_holds, tag); 2426 ASSERT(holds >= 0); 2427 2428 /* 2429 * We can't freeze indirects if there is a possibility that they 2430 * may be modified in the current syncing context. 2431 */ 2432 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0)) 2433 arc_buf_freeze(db->db_buf); 2434 2435 if (holds == db->db_dirtycnt && 2436 db->db_level == 0 && db->db_user_immediate_evict) 2437 dbuf_evict_user(db); 2438 2439 if (holds == 0) { 2440 if (db->db_blkid == DMU_BONUS_BLKID) { 2441 dnode_t *dn; 2442 boolean_t evict_dbuf = db->db_pending_evict; 2443 2444 /* 2445 * If the dnode moves here, we cannot cross this 2446 * barrier until the move completes. 2447 */ 2448 DB_DNODE_ENTER(db); 2449 2450 dn = DB_DNODE(db); 2451 atomic_dec_32(&dn->dn_dbufs_count); 2452 2453 /* 2454 * Decrementing the dbuf count means that the bonus 2455 * buffer's dnode hold is no longer discounted in 2456 * dnode_move(). The dnode cannot move until after 2457 * the dnode_rele() below. 2458 */ 2459 DB_DNODE_EXIT(db); 2460 2461 /* 2462 * Do not reference db after its lock is dropped. 2463 * Another thread may evict it. 2464 */ 2465 mutex_exit(&db->db_mtx); 2466 2467 if (evict_dbuf) 2468 dnode_evict_bonus(dn); 2469 2470 dnode_rele(dn, db); 2471 } else if (db->db_buf == NULL) { 2472 /* 2473 * This is a special case: we never associated this 2474 * dbuf with any data allocated from the ARC. 2475 */ 2476 ASSERT(db->db_state == DB_UNCACHED || 2477 db->db_state == DB_NOFILL); 2478 dbuf_evict(db); 2479 } else if (arc_released(db->db_buf)) { 2480 arc_buf_t *buf = db->db_buf; 2481 /* 2482 * This dbuf has anonymous data associated with it. 2483 */ 2484 dbuf_clear_data(db); 2485 VERIFY(arc_buf_remove_ref(buf, db)); 2486 dbuf_evict(db); 2487 } else { 2488 VERIFY(!arc_buf_remove_ref(db->db_buf, db)); 2489 2490 /* 2491 * A dbuf will be eligible for eviction if either the 2492 * 'primarycache' property is set or a duplicate 2493 * copy of this buffer is already cached in the arc. 2494 * 2495 * In the case of the 'primarycache' a buffer 2496 * is considered for eviction if it matches the 2497 * criteria set in the property. 2498 * 2499 * To decide if our buffer is considered a 2500 * duplicate, we must call into the arc to determine 2501 * if multiple buffers are referencing the same 2502 * block on-disk. If so, then we simply evict 2503 * ourselves. 2504 */ 2505 if (!DBUF_IS_CACHEABLE(db)) { 2506 if (db->db_blkptr != NULL && 2507 !BP_IS_HOLE(db->db_blkptr) && 2508 !BP_IS_EMBEDDED(db->db_blkptr)) { 2509 spa_t *spa = 2510 dmu_objset_spa(db->db_objset); 2511 blkptr_t bp = *db->db_blkptr; 2512 dbuf_clear(db); 2513 arc_freed(spa, &bp); 2514 } else { 2515 dbuf_clear(db); 2516 } 2517 } else if (db->db_pending_evict || 2518 arc_buf_eviction_needed(db->db_buf)) { 2519 dbuf_clear(db); 2520 } else { 2521 mutex_exit(&db->db_mtx); 2522 } 2523 } 2524 } else { 2525 mutex_exit(&db->db_mtx); 2526 } 2527 } 2528 2529 #pragma weak dmu_buf_refcount = dbuf_refcount 2530 uint64_t 2531 dbuf_refcount(dmu_buf_impl_t *db) 2532 { 2533 return (refcount_count(&db->db_holds)); 2534 } 2535 2536 void * 2537 dmu_buf_replace_user(dmu_buf_t *db_fake, dmu_buf_user_t *old_user, 2538 dmu_buf_user_t *new_user) 2539 { 2540 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2541 2542 mutex_enter(&db->db_mtx); 2543 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2544 if (db->db_user == old_user) 2545 db->db_user = new_user; 2546 else 2547 old_user = db->db_user; 2548 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2549 mutex_exit(&db->db_mtx); 2550 2551 return (old_user); 2552 } 2553 2554 void * 2555 dmu_buf_set_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2556 { 2557 return (dmu_buf_replace_user(db_fake, NULL, user)); 2558 } 2559 2560 void * 2561 dmu_buf_set_user_ie(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2562 { 2563 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2564 2565 db->db_user_immediate_evict = TRUE; 2566 return (dmu_buf_set_user(db_fake, user)); 2567 } 2568 2569 void * 2570 dmu_buf_remove_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) 2571 { 2572 return (dmu_buf_replace_user(db_fake, user, NULL)); 2573 } 2574 2575 void * 2576 dmu_buf_get_user(dmu_buf_t *db_fake) 2577 { 2578 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2579 2580 dbuf_verify_user(db, DBVU_NOT_EVICTING); 2581 return (db->db_user); 2582 } 2583 2584 void 2585 dmu_buf_user_evict_wait() 2586 { 2587 taskq_wait(dbu_evict_taskq); 2588 } 2589 2590 boolean_t 2591 dmu_buf_freeable(dmu_buf_t *dbuf) 2592 { 2593 boolean_t res = B_FALSE; 2594 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 2595 2596 if (db->db_blkptr) 2597 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset, 2598 db->db_blkptr, db->db_blkptr->blk_birth); 2599 2600 return (res); 2601 } 2602 2603 blkptr_t * 2604 dmu_buf_get_blkptr(dmu_buf_t *db) 2605 { 2606 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; 2607 return (dbi->db_blkptr); 2608 } 2609 2610 static void 2611 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db) 2612 { 2613 /* ASSERT(dmu_tx_is_syncing(tx) */ 2614 ASSERT(MUTEX_HELD(&db->db_mtx)); 2615 2616 if (db->db_blkptr != NULL) 2617 return; 2618 2619 if (db->db_blkid == DMU_SPILL_BLKID) { 2620 db->db_blkptr = &dn->dn_phys->dn_spill; 2621 BP_ZERO(db->db_blkptr); 2622 return; 2623 } 2624 if (db->db_level == dn->dn_phys->dn_nlevels-1) { 2625 /* 2626 * This buffer was allocated at a time when there was 2627 * no available blkptrs from the dnode, or it was 2628 * inappropriate to hook it in (i.e., nlevels mis-match). 2629 */ 2630 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr); 2631 ASSERT(db->db_parent == NULL); 2632 db->db_parent = dn->dn_dbuf; 2633 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid]; 2634 DBUF_VERIFY(db); 2635 } else { 2636 dmu_buf_impl_t *parent = db->db_parent; 2637 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2638 2639 ASSERT(dn->dn_phys->dn_nlevels > 1); 2640 if (parent == NULL) { 2641 mutex_exit(&db->db_mtx); 2642 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2643 parent = dbuf_hold_level(dn, db->db_level + 1, 2644 db->db_blkid >> epbs, db); 2645 rw_exit(&dn->dn_struct_rwlock); 2646 mutex_enter(&db->db_mtx); 2647 db->db_parent = parent; 2648 } 2649 db->db_blkptr = (blkptr_t *)parent->db.db_data + 2650 (db->db_blkid & ((1ULL << epbs) - 1)); 2651 DBUF_VERIFY(db); 2652 } 2653 } 2654 2655 static void 2656 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2657 { 2658 dmu_buf_impl_t *db = dr->dr_dbuf; 2659 dnode_t *dn; 2660 zio_t *zio; 2661 2662 ASSERT(dmu_tx_is_syncing(tx)); 2663 2664 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2665 2666 mutex_enter(&db->db_mtx); 2667 2668 ASSERT(db->db_level > 0); 2669 DBUF_VERIFY(db); 2670 2671 /* Read the block if it hasn't been read yet. */ 2672 if (db->db_buf == NULL) { 2673 mutex_exit(&db->db_mtx); 2674 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); 2675 mutex_enter(&db->db_mtx); 2676 } 2677 ASSERT3U(db->db_state, ==, DB_CACHED); 2678 ASSERT(db->db_buf != NULL); 2679 2680 DB_DNODE_ENTER(db); 2681 dn = DB_DNODE(db); 2682 /* Indirect block size must match what the dnode thinks it is. */ 2683 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2684 dbuf_check_blkptr(dn, db); 2685 DB_DNODE_EXIT(db); 2686 2687 /* Provide the pending dirty record to child dbufs */ 2688 db->db_data_pending = dr; 2689 2690 mutex_exit(&db->db_mtx); 2691 dbuf_write(dr, db->db_buf, tx); 2692 2693 zio = dr->dr_zio; 2694 mutex_enter(&dr->dt.di.dr_mtx); 2695 dbuf_sync_list(&dr->dt.di.dr_children, db->db_level - 1, tx); 2696 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2697 mutex_exit(&dr->dt.di.dr_mtx); 2698 zio_nowait(zio); 2699 } 2700 2701 static void 2702 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2703 { 2704 arc_buf_t **datap = &dr->dt.dl.dr_data; 2705 dmu_buf_impl_t *db = dr->dr_dbuf; 2706 dnode_t *dn; 2707 objset_t *os; 2708 uint64_t txg = tx->tx_txg; 2709 2710 ASSERT(dmu_tx_is_syncing(tx)); 2711 2712 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2713 2714 mutex_enter(&db->db_mtx); 2715 /* 2716 * To be synced, we must be dirtied. But we 2717 * might have been freed after the dirty. 2718 */ 2719 if (db->db_state == DB_UNCACHED) { 2720 /* This buffer has been freed since it was dirtied */ 2721 ASSERT(db->db.db_data == NULL); 2722 } else if (db->db_state == DB_FILL) { 2723 /* This buffer was freed and is now being re-filled */ 2724 ASSERT(db->db.db_data != dr->dt.dl.dr_data); 2725 } else { 2726 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); 2727 } 2728 DBUF_VERIFY(db); 2729 2730 DB_DNODE_ENTER(db); 2731 dn = DB_DNODE(db); 2732 2733 if (db->db_blkid == DMU_SPILL_BLKID) { 2734 mutex_enter(&dn->dn_mtx); 2735 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR; 2736 mutex_exit(&dn->dn_mtx); 2737 } 2738 2739 /* 2740 * If this is a bonus buffer, simply copy the bonus data into the 2741 * dnode. It will be written out when the dnode is synced (and it 2742 * will be synced, since it must have been dirty for dbuf_sync to 2743 * be called). 2744 */ 2745 if (db->db_blkid == DMU_BONUS_BLKID) { 2746 dbuf_dirty_record_t **drp; 2747 2748 ASSERT(*datap != NULL); 2749 ASSERT0(db->db_level); 2750 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN); 2751 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen); 2752 DB_DNODE_EXIT(db); 2753 2754 if (*datap != db->db.db_data) { 2755 zio_buf_free(*datap, DN_MAX_BONUSLEN); 2756 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 2757 } 2758 db->db_data_pending = NULL; 2759 drp = &db->db_last_dirty; 2760 while (*drp != dr) 2761 drp = &(*drp)->dr_next; 2762 ASSERT(dr->dr_next == NULL); 2763 ASSERT(dr->dr_dbuf == db); 2764 *drp = dr->dr_next; 2765 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2766 ASSERT(db->db_dirtycnt > 0); 2767 db->db_dirtycnt -= 1; 2768 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2769 return; 2770 } 2771 2772 os = dn->dn_objset; 2773 2774 /* 2775 * This function may have dropped the db_mtx lock allowing a dmu_sync 2776 * operation to sneak in. As a result, we need to ensure that we 2777 * don't check the dr_override_state until we have returned from 2778 * dbuf_check_blkptr. 2779 */ 2780 dbuf_check_blkptr(dn, db); 2781 2782 /* 2783 * If this buffer is in the middle of an immediate write, 2784 * wait for the synchronous IO to complete. 2785 */ 2786 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) { 2787 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); 2788 cv_wait(&db->db_changed, &db->db_mtx); 2789 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN); 2790 } 2791 2792 if (db->db_state != DB_NOFILL && 2793 dn->dn_object != DMU_META_DNODE_OBJECT && 2794 refcount_count(&db->db_holds) > 1 && 2795 dr->dt.dl.dr_override_state != DR_OVERRIDDEN && 2796 *datap == db->db_buf) { 2797 /* 2798 * If this buffer is currently "in use" (i.e., there 2799 * are active holds and db_data still references it), 2800 * then make a copy before we start the write so that 2801 * any modifications from the open txg will not leak 2802 * into this write. 2803 * 2804 * NOTE: this copy does not need to be made for 2805 * objects only modified in the syncing context (e.g. 2806 * DNONE_DNODE blocks). 2807 */ 2808 int blksz = arc_buf_size(*datap); 2809 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2810 *datap = arc_buf_alloc(os->os_spa, blksz, db, type); 2811 bcopy(db->db.db_data, (*datap)->b_data, blksz); 2812 } 2813 db->db_data_pending = dr; 2814 2815 mutex_exit(&db->db_mtx); 2816 2817 dbuf_write(dr, *datap, tx); 2818 2819 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2820 if (dn->dn_object == DMU_META_DNODE_OBJECT) { 2821 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr); 2822 DB_DNODE_EXIT(db); 2823 } else { 2824 /* 2825 * Although zio_nowait() does not "wait for an IO", it does 2826 * initiate the IO. If this is an empty write it seems plausible 2827 * that the IO could actually be completed before the nowait 2828 * returns. We need to DB_DNODE_EXIT() first in case 2829 * zio_nowait() invalidates the dbuf. 2830 */ 2831 DB_DNODE_EXIT(db); 2832 zio_nowait(dr->dr_zio); 2833 } 2834 } 2835 2836 void 2837 dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx) 2838 { 2839 dbuf_dirty_record_t *dr; 2840 2841 while (dr = list_head(list)) { 2842 if (dr->dr_zio != NULL) { 2843 /* 2844 * If we find an already initialized zio then we 2845 * are processing the meta-dnode, and we have finished. 2846 * The dbufs for all dnodes are put back on the list 2847 * during processing, so that we can zio_wait() 2848 * these IOs after initiating all child IOs. 2849 */ 2850 ASSERT3U(dr->dr_dbuf->db.db_object, ==, 2851 DMU_META_DNODE_OBJECT); 2852 break; 2853 } 2854 if (dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID && 2855 dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) { 2856 VERIFY3U(dr->dr_dbuf->db_level, ==, level); 2857 } 2858 list_remove(list, dr); 2859 if (dr->dr_dbuf->db_level > 0) 2860 dbuf_sync_indirect(dr, tx); 2861 else 2862 dbuf_sync_leaf(dr, tx); 2863 } 2864 } 2865 2866 /* ARGSUSED */ 2867 static void 2868 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb) 2869 { 2870 dmu_buf_impl_t *db = vdb; 2871 dnode_t *dn; 2872 blkptr_t *bp = zio->io_bp; 2873 blkptr_t *bp_orig = &zio->io_bp_orig; 2874 spa_t *spa = zio->io_spa; 2875 int64_t delta; 2876 uint64_t fill = 0; 2877 int i; 2878 2879 ASSERT3P(db->db_blkptr, ==, bp); 2880 2881 DB_DNODE_ENTER(db); 2882 dn = DB_DNODE(db); 2883 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig); 2884 dnode_diduse_space(dn, delta - zio->io_prev_space_delta); 2885 zio->io_prev_space_delta = delta; 2886 2887 if (bp->blk_birth != 0) { 2888 ASSERT((db->db_blkid != DMU_SPILL_BLKID && 2889 BP_GET_TYPE(bp) == dn->dn_type) || 2890 (db->db_blkid == DMU_SPILL_BLKID && 2891 BP_GET_TYPE(bp) == dn->dn_bonustype) || 2892 BP_IS_EMBEDDED(bp)); 2893 ASSERT(BP_GET_LEVEL(bp) == db->db_level); 2894 } 2895 2896 mutex_enter(&db->db_mtx); 2897 2898 #ifdef ZFS_DEBUG 2899 if (db->db_blkid == DMU_SPILL_BLKID) { 2900 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2901 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2902 db->db_blkptr == &dn->dn_phys->dn_spill); 2903 } 2904 #endif 2905 2906 if (db->db_level == 0) { 2907 mutex_enter(&dn->dn_mtx); 2908 if (db->db_blkid > dn->dn_phys->dn_maxblkid && 2909 db->db_blkid != DMU_SPILL_BLKID) 2910 dn->dn_phys->dn_maxblkid = db->db_blkid; 2911 mutex_exit(&dn->dn_mtx); 2912 2913 if (dn->dn_type == DMU_OT_DNODE) { 2914 dnode_phys_t *dnp = db->db.db_data; 2915 for (i = db->db.db_size >> DNODE_SHIFT; i > 0; 2916 i--, dnp++) { 2917 if (dnp->dn_type != DMU_OT_NONE) 2918 fill++; 2919 } 2920 } else { 2921 if (BP_IS_HOLE(bp)) { 2922 fill = 0; 2923 } else { 2924 fill = 1; 2925 } 2926 } 2927 } else { 2928 blkptr_t *ibp = db->db.db_data; 2929 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2930 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) { 2931 if (BP_IS_HOLE(ibp)) 2932 continue; 2933 fill += BP_GET_FILL(ibp); 2934 } 2935 } 2936 DB_DNODE_EXIT(db); 2937 2938 if (!BP_IS_EMBEDDED(bp)) 2939 bp->blk_fill = fill; 2940 2941 mutex_exit(&db->db_mtx); 2942 } 2943 2944 /* 2945 * The SPA will call this callback several times for each zio - once 2946 * for every physical child i/o (zio->io_phys_children times). This 2947 * allows the DMU to monitor the progress of each logical i/o. For example, 2948 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z 2949 * block. There may be a long delay before all copies/fragments are completed, 2950 * so this callback allows us to retire dirty space gradually, as the physical 2951 * i/os complete. 2952 */ 2953 /* ARGSUSED */ 2954 static void 2955 dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg) 2956 { 2957 dmu_buf_impl_t *db = arg; 2958 objset_t *os = db->db_objset; 2959 dsl_pool_t *dp = dmu_objset_pool(os); 2960 dbuf_dirty_record_t *dr; 2961 int delta = 0; 2962 2963 dr = db->db_data_pending; 2964 ASSERT3U(dr->dr_txg, ==, zio->io_txg); 2965 2966 /* 2967 * The callback will be called io_phys_children times. Retire one 2968 * portion of our dirty space each time we are called. Any rounding 2969 * error will be cleaned up by dsl_pool_sync()'s call to 2970 * dsl_pool_undirty_space(). 2971 */ 2972 delta = dr->dr_accounted / zio->io_phys_children; 2973 dsl_pool_undirty_space(dp, delta, zio->io_txg); 2974 } 2975 2976 /* ARGSUSED */ 2977 static void 2978 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb) 2979 { 2980 dmu_buf_impl_t *db = vdb; 2981 blkptr_t *bp_orig = &zio->io_bp_orig; 2982 blkptr_t *bp = db->db_blkptr; 2983 objset_t *os = db->db_objset; 2984 dmu_tx_t *tx = os->os_synctx; 2985 dbuf_dirty_record_t **drp, *dr; 2986 2987 ASSERT0(zio->io_error); 2988 ASSERT(db->db_blkptr == bp); 2989 2990 /* 2991 * For nopwrites and rewrites we ensure that the bp matches our 2992 * original and bypass all the accounting. 2993 */ 2994 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) { 2995 ASSERT(BP_EQUAL(bp, bp_orig)); 2996 } else { 2997 dsl_dataset_t *ds = os->os_dsl_dataset; 2998 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE); 2999 dsl_dataset_block_born(ds, bp, tx); 3000 } 3001 3002 mutex_enter(&db->db_mtx); 3003 3004 DBUF_VERIFY(db); 3005 3006 drp = &db->db_last_dirty; 3007 while ((dr = *drp) != db->db_data_pending) 3008 drp = &dr->dr_next; 3009 ASSERT(!list_link_active(&dr->dr_dirty_node)); 3010 ASSERT(dr->dr_dbuf == db); 3011 ASSERT(dr->dr_next == NULL); 3012 *drp = dr->dr_next; 3013 3014 #ifdef ZFS_DEBUG 3015 if (db->db_blkid == DMU_SPILL_BLKID) { 3016 dnode_t *dn; 3017 3018 DB_DNODE_ENTER(db); 3019 dn = DB_DNODE(db); 3020 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 3021 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 3022 db->db_blkptr == &dn->dn_phys->dn_spill); 3023 DB_DNODE_EXIT(db); 3024 } 3025 #endif 3026 3027 if (db->db_level == 0) { 3028 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 3029 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN); 3030 if (db->db_state != DB_NOFILL) { 3031 if (dr->dt.dl.dr_data != db->db_buf) 3032 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 3033 db)); 3034 else if (!arc_released(db->db_buf)) 3035 arc_set_callback(db->db_buf, dbuf_do_evict, db); 3036 } 3037 } else { 3038 dnode_t *dn; 3039 3040 DB_DNODE_ENTER(db); 3041 dn = DB_DNODE(db); 3042 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 3043 ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift); 3044 if (!BP_IS_HOLE(db->db_blkptr)) { 3045 int epbs = 3046 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 3047 ASSERT3U(db->db_blkid, <=, 3048 dn->dn_phys->dn_maxblkid >> (db->db_level * epbs)); 3049 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, 3050 db->db.db_size); 3051 if (!arc_released(db->db_buf)) 3052 arc_set_callback(db->db_buf, dbuf_do_evict, db); 3053 } 3054 DB_DNODE_EXIT(db); 3055 mutex_destroy(&dr->dt.di.dr_mtx); 3056 list_destroy(&dr->dt.di.dr_children); 3057 } 3058 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 3059 3060 cv_broadcast(&db->db_changed); 3061 ASSERT(db->db_dirtycnt > 0); 3062 db->db_dirtycnt -= 1; 3063 db->db_data_pending = NULL; 3064 dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg); 3065 } 3066 3067 static void 3068 dbuf_write_nofill_ready(zio_t *zio) 3069 { 3070 dbuf_write_ready(zio, NULL, zio->io_private); 3071 } 3072 3073 static void 3074 dbuf_write_nofill_done(zio_t *zio) 3075 { 3076 dbuf_write_done(zio, NULL, zio->io_private); 3077 } 3078 3079 static void 3080 dbuf_write_override_ready(zio_t *zio) 3081 { 3082 dbuf_dirty_record_t *dr = zio->io_private; 3083 dmu_buf_impl_t *db = dr->dr_dbuf; 3084 3085 dbuf_write_ready(zio, NULL, db); 3086 } 3087 3088 static void 3089 dbuf_write_override_done(zio_t *zio) 3090 { 3091 dbuf_dirty_record_t *dr = zio->io_private; 3092 dmu_buf_impl_t *db = dr->dr_dbuf; 3093 blkptr_t *obp = &dr->dt.dl.dr_overridden_by; 3094 3095 mutex_enter(&db->db_mtx); 3096 if (!BP_EQUAL(zio->io_bp, obp)) { 3097 if (!BP_IS_HOLE(obp)) 3098 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp); 3099 arc_release(dr->dt.dl.dr_data, db); 3100 } 3101 mutex_exit(&db->db_mtx); 3102 3103 dbuf_write_done(zio, NULL, db); 3104 } 3105 3106 /* Issue I/O to commit a dirty buffer to disk. */ 3107 static void 3108 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) 3109 { 3110 dmu_buf_impl_t *db = dr->dr_dbuf; 3111 dnode_t *dn; 3112 objset_t *os; 3113 dmu_buf_impl_t *parent = db->db_parent; 3114 uint64_t txg = tx->tx_txg; 3115 zbookmark_phys_t zb; 3116 zio_prop_t zp; 3117 zio_t *zio; 3118 int wp_flag = 0; 3119 3120 DB_DNODE_ENTER(db); 3121 dn = DB_DNODE(db); 3122 os = dn->dn_objset; 3123 3124 if (db->db_state != DB_NOFILL) { 3125 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) { 3126 /* 3127 * Private object buffers are released here rather 3128 * than in dbuf_dirty() since they are only modified 3129 * in the syncing context and we don't want the 3130 * overhead of making multiple copies of the data. 3131 */ 3132 if (BP_IS_HOLE(db->db_blkptr)) { 3133 arc_buf_thaw(data); 3134 } else { 3135 dbuf_release_bp(db); 3136 } 3137 } 3138 } 3139 3140 if (parent != dn->dn_dbuf) { 3141 /* Our parent is an indirect block. */ 3142 /* We have a dirty parent that has been scheduled for write. */ 3143 ASSERT(parent && parent->db_data_pending); 3144 /* Our parent's buffer is one level closer to the dnode. */ 3145 ASSERT(db->db_level == parent->db_level-1); 3146 /* 3147 * We're about to modify our parent's db_data by modifying 3148 * our block pointer, so the parent must be released. 3149 */ 3150 ASSERT(arc_released(parent->db_buf)); 3151 zio = parent->db_data_pending->dr_zio; 3152 } else { 3153 /* Our parent is the dnode itself. */ 3154 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && 3155 db->db_blkid != DMU_SPILL_BLKID) || 3156 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); 3157 if (db->db_blkid != DMU_SPILL_BLKID) 3158 ASSERT3P(db->db_blkptr, ==, 3159 &dn->dn_phys->dn_blkptr[db->db_blkid]); 3160 zio = dn->dn_zio; 3161 } 3162 3163 ASSERT(db->db_level == 0 || data == db->db_buf); 3164 ASSERT3U(db->db_blkptr->blk_birth, <=, txg); 3165 ASSERT(zio); 3166 3167 SET_BOOKMARK(&zb, os->os_dsl_dataset ? 3168 os->os_dsl_dataset->ds_object : DMU_META_OBJSET, 3169 db->db.db_object, db->db_level, db->db_blkid); 3170 3171 if (db->db_blkid == DMU_SPILL_BLKID) 3172 wp_flag = WP_SPILL; 3173 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0; 3174 3175 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp); 3176 DB_DNODE_EXIT(db); 3177 3178 if (db->db_level == 0 && 3179 dr->dt.dl.dr_override_state == DR_OVERRIDDEN) { 3180 /* 3181 * The BP for this block has been provided by open context 3182 * (by dmu_sync() or dmu_buf_write_embedded()). 3183 */ 3184 void *contents = (data != NULL) ? data->b_data : NULL; 3185 3186 dr->dr_zio = zio_write(zio, os->os_spa, txg, 3187 db->db_blkptr, contents, db->db.db_size, &zp, 3188 dbuf_write_override_ready, NULL, dbuf_write_override_done, 3189 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 3190 mutex_enter(&db->db_mtx); 3191 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 3192 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by, 3193 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite); 3194 mutex_exit(&db->db_mtx); 3195 } else if (db->db_state == DB_NOFILL) { 3196 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF || 3197 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY); 3198 dr->dr_zio = zio_write(zio, os->os_spa, txg, 3199 db->db_blkptr, NULL, db->db.db_size, &zp, 3200 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db, 3201 ZIO_PRIORITY_ASYNC_WRITE, 3202 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb); 3203 } else { 3204 ASSERT(arc_released(data)); 3205 dr->dr_zio = arc_write(zio, os->os_spa, txg, 3206 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), 3207 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready, 3208 dbuf_write_physdone, dbuf_write_done, db, 3209 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 3210 } 3211 } 3212