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, 2014 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 */ 28 29 #include <sys/zfs_context.h> 30 #include <sys/dmu.h> 31 #include <sys/dmu_send.h> 32 #include <sys/dmu_impl.h> 33 #include <sys/dbuf.h> 34 #include <sys/dmu_objset.h> 35 #include <sys/dsl_dataset.h> 36 #include <sys/dsl_dir.h> 37 #include <sys/dmu_tx.h> 38 #include <sys/spa.h> 39 #include <sys/zio.h> 40 #include <sys/dmu_zfetch.h> 41 #include <sys/sa.h> 42 #include <sys/sa_impl.h> 43 #include <sys/zfeature.h> 44 #include <sys/blkptr.h> 45 #include <sys/range_tree.h> 46 47 /* 48 * Number of times that zfs_free_range() took the slow path while doing 49 * a zfs receive. A nonzero value indicates a potential performance problem. 50 */ 51 uint64_t zfs_free_range_recv_miss; 52 53 static void dbuf_destroy(dmu_buf_impl_t *db); 54 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 55 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx); 56 57 /* 58 * Global data structures and functions for the dbuf cache. 59 */ 60 static kmem_cache_t *dbuf_cache; 61 62 /* ARGSUSED */ 63 static int 64 dbuf_cons(void *vdb, void *unused, int kmflag) 65 { 66 dmu_buf_impl_t *db = vdb; 67 bzero(db, sizeof (dmu_buf_impl_t)); 68 69 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL); 70 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL); 71 refcount_create(&db->db_holds); 72 73 return (0); 74 } 75 76 /* ARGSUSED */ 77 static void 78 dbuf_dest(void *vdb, void *unused) 79 { 80 dmu_buf_impl_t *db = vdb; 81 mutex_destroy(&db->db_mtx); 82 cv_destroy(&db->db_changed); 83 refcount_destroy(&db->db_holds); 84 } 85 86 /* 87 * dbuf hash table routines 88 */ 89 static dbuf_hash_table_t dbuf_hash_table; 90 91 static uint64_t dbuf_hash_count; 92 93 static uint64_t 94 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid) 95 { 96 uintptr_t osv = (uintptr_t)os; 97 uint64_t crc = -1ULL; 98 99 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); 100 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF]; 101 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF]; 102 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF]; 103 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF]; 104 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF]; 105 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF]; 106 107 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16); 108 109 return (crc); 110 } 111 112 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid); 113 114 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \ 115 ((dbuf)->db.db_object == (obj) && \ 116 (dbuf)->db_objset == (os) && \ 117 (dbuf)->db_level == (level) && \ 118 (dbuf)->db_blkid == (blkid)) 119 120 dmu_buf_impl_t * 121 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid) 122 { 123 dbuf_hash_table_t *h = &dbuf_hash_table; 124 objset_t *os = dn->dn_objset; 125 uint64_t obj = dn->dn_object; 126 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 127 uint64_t idx = hv & h->hash_table_mask; 128 dmu_buf_impl_t *db; 129 130 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 131 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) { 132 if (DBUF_EQUAL(db, os, obj, level, blkid)) { 133 mutex_enter(&db->db_mtx); 134 if (db->db_state != DB_EVICTING) { 135 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 136 return (db); 137 } 138 mutex_exit(&db->db_mtx); 139 } 140 } 141 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 142 return (NULL); 143 } 144 145 /* 146 * Insert an entry into the hash table. If there is already an element 147 * equal to elem in the hash table, then the already existing element 148 * will be returned and the new element will not be inserted. 149 * Otherwise returns NULL. 150 */ 151 static dmu_buf_impl_t * 152 dbuf_hash_insert(dmu_buf_impl_t *db) 153 { 154 dbuf_hash_table_t *h = &dbuf_hash_table; 155 objset_t *os = db->db_objset; 156 uint64_t obj = db->db.db_object; 157 int level = db->db_level; 158 uint64_t blkid = db->db_blkid; 159 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 160 uint64_t idx = hv & h->hash_table_mask; 161 dmu_buf_impl_t *dbf; 162 163 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 164 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) { 165 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) { 166 mutex_enter(&dbf->db_mtx); 167 if (dbf->db_state != DB_EVICTING) { 168 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 169 return (dbf); 170 } 171 mutex_exit(&dbf->db_mtx); 172 } 173 } 174 175 mutex_enter(&db->db_mtx); 176 db->db_hash_next = h->hash_table[idx]; 177 h->hash_table[idx] = db; 178 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 179 atomic_inc_64(&dbuf_hash_count); 180 181 return (NULL); 182 } 183 184 /* 185 * Remove an entry from the hash table. It must be in the EVICTING state. 186 */ 187 static void 188 dbuf_hash_remove(dmu_buf_impl_t *db) 189 { 190 dbuf_hash_table_t *h = &dbuf_hash_table; 191 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object, 192 db->db_level, db->db_blkid); 193 uint64_t idx = hv & h->hash_table_mask; 194 dmu_buf_impl_t *dbf, **dbp; 195 196 /* 197 * We musn't hold db_mtx to maintain lock ordering: 198 * DBUF_HASH_MUTEX > db_mtx. 199 */ 200 ASSERT(refcount_is_zero(&db->db_holds)); 201 ASSERT(db->db_state == DB_EVICTING); 202 ASSERT(!MUTEX_HELD(&db->db_mtx)); 203 204 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 205 dbp = &h->hash_table[idx]; 206 while ((dbf = *dbp) != db) { 207 dbp = &dbf->db_hash_next; 208 ASSERT(dbf != NULL); 209 } 210 *dbp = db->db_hash_next; 211 db->db_hash_next = NULL; 212 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 213 atomic_dec_64(&dbuf_hash_count); 214 } 215 216 static arc_evict_func_t dbuf_do_evict; 217 218 static void 219 dbuf_evict_user(dmu_buf_impl_t *db) 220 { 221 ASSERT(MUTEX_HELD(&db->db_mtx)); 222 223 if (db->db_level != 0 || db->db_evict_func == NULL) 224 return; 225 226 db->db_evict_func(&db->db, db->db_user_ptr); 227 db->db_user_ptr = NULL; 228 db->db_evict_func = NULL; 229 } 230 231 boolean_t 232 dbuf_is_metadata(dmu_buf_impl_t *db) 233 { 234 if (db->db_level > 0) { 235 return (B_TRUE); 236 } else { 237 boolean_t is_metadata; 238 239 DB_DNODE_ENTER(db); 240 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type); 241 DB_DNODE_EXIT(db); 242 243 return (is_metadata); 244 } 245 } 246 247 void 248 dbuf_evict(dmu_buf_impl_t *db) 249 { 250 ASSERT(MUTEX_HELD(&db->db_mtx)); 251 ASSERT(db->db_buf == NULL); 252 ASSERT(db->db_data_pending == NULL); 253 254 dbuf_clear(db); 255 dbuf_destroy(db); 256 } 257 258 void 259 dbuf_init(void) 260 { 261 uint64_t hsize = 1ULL << 16; 262 dbuf_hash_table_t *h = &dbuf_hash_table; 263 int i; 264 265 /* 266 * The hash table is big enough to fill all of physical memory 267 * with an average 4K block size. The table will take up 268 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers). 269 */ 270 while (hsize * 4096 < physmem * PAGESIZE) 271 hsize <<= 1; 272 273 retry: 274 h->hash_table_mask = hsize - 1; 275 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP); 276 if (h->hash_table == NULL) { 277 /* XXX - we should really return an error instead of assert */ 278 ASSERT(hsize > (1ULL << 10)); 279 hsize >>= 1; 280 goto retry; 281 } 282 283 dbuf_cache = kmem_cache_create("dmu_buf_impl_t", 284 sizeof (dmu_buf_impl_t), 285 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0); 286 287 for (i = 0; i < DBUF_MUTEXES; i++) 288 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL); 289 } 290 291 void 292 dbuf_fini(void) 293 { 294 dbuf_hash_table_t *h = &dbuf_hash_table; 295 int i; 296 297 for (i = 0; i < DBUF_MUTEXES; i++) 298 mutex_destroy(&h->hash_mutexes[i]); 299 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *)); 300 kmem_cache_destroy(dbuf_cache); 301 } 302 303 /* 304 * Other stuff. 305 */ 306 307 #ifdef ZFS_DEBUG 308 static void 309 dbuf_verify(dmu_buf_impl_t *db) 310 { 311 dnode_t *dn; 312 dbuf_dirty_record_t *dr; 313 314 ASSERT(MUTEX_HELD(&db->db_mtx)); 315 316 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY)) 317 return; 318 319 ASSERT(db->db_objset != NULL); 320 DB_DNODE_ENTER(db); 321 dn = DB_DNODE(db); 322 if (dn == NULL) { 323 ASSERT(db->db_parent == NULL); 324 ASSERT(db->db_blkptr == NULL); 325 } else { 326 ASSERT3U(db->db.db_object, ==, dn->dn_object); 327 ASSERT3P(db->db_objset, ==, dn->dn_objset); 328 ASSERT3U(db->db_level, <, dn->dn_nlevels); 329 ASSERT(db->db_blkid == DMU_BONUS_BLKID || 330 db->db_blkid == DMU_SPILL_BLKID || 331 !avl_is_empty(&dn->dn_dbufs)); 332 } 333 if (db->db_blkid == DMU_BONUS_BLKID) { 334 ASSERT(dn != NULL); 335 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 336 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID); 337 } else if (db->db_blkid == DMU_SPILL_BLKID) { 338 ASSERT(dn != NULL); 339 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 340 ASSERT0(db->db.db_offset); 341 } else { 342 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size); 343 } 344 345 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next) 346 ASSERT(dr->dr_dbuf == db); 347 348 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next) 349 ASSERT(dr->dr_dbuf == db); 350 351 /* 352 * We can't assert that db_size matches dn_datablksz because it 353 * can be momentarily different when another thread is doing 354 * dnode_set_blksz(). 355 */ 356 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) { 357 dr = db->db_data_pending; 358 /* 359 * It should only be modified in syncing context, so 360 * make sure we only have one copy of the data. 361 */ 362 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf); 363 } 364 365 /* verify db->db_blkptr */ 366 if (db->db_blkptr) { 367 if (db->db_parent == dn->dn_dbuf) { 368 /* db is pointed to by the dnode */ 369 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */ 370 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object)) 371 ASSERT(db->db_parent == NULL); 372 else 373 ASSERT(db->db_parent != NULL); 374 if (db->db_blkid != DMU_SPILL_BLKID) 375 ASSERT3P(db->db_blkptr, ==, 376 &dn->dn_phys->dn_blkptr[db->db_blkid]); 377 } else { 378 /* db is pointed to by an indirect block */ 379 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT; 380 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1); 381 ASSERT3U(db->db_parent->db.db_object, ==, 382 db->db.db_object); 383 /* 384 * dnode_grow_indblksz() can make this fail if we don't 385 * have the struct_rwlock. XXX indblksz no longer 386 * grows. safe to do this now? 387 */ 388 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 389 ASSERT3P(db->db_blkptr, ==, 390 ((blkptr_t *)db->db_parent->db.db_data + 391 db->db_blkid % epb)); 392 } 393 } 394 } 395 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) && 396 (db->db_buf == NULL || db->db_buf->b_data) && 397 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID && 398 db->db_state != DB_FILL && !dn->dn_free_txg) { 399 /* 400 * If the blkptr isn't set but they have nonzero data, 401 * it had better be dirty, otherwise we'll lose that 402 * data when we evict this buffer. 403 */ 404 if (db->db_dirtycnt == 0) { 405 uint64_t *buf = db->db.db_data; 406 int i; 407 408 for (i = 0; i < db->db.db_size >> 3; i++) { 409 ASSERT(buf[i] == 0); 410 } 411 } 412 } 413 DB_DNODE_EXIT(db); 414 } 415 #endif 416 417 static void 418 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf) 419 { 420 ASSERT(MUTEX_HELD(&db->db_mtx)); 421 db->db_buf = buf; 422 if (buf != NULL) { 423 ASSERT(buf->b_data != NULL); 424 db->db.db_data = buf->b_data; 425 if (!arc_released(buf)) 426 arc_set_callback(buf, dbuf_do_evict, db); 427 } else { 428 dbuf_evict_user(db); 429 db->db.db_data = NULL; 430 if (db->db_state != DB_NOFILL) 431 db->db_state = DB_UNCACHED; 432 } 433 } 434 435 /* 436 * Loan out an arc_buf for read. Return the loaned arc_buf. 437 */ 438 arc_buf_t * 439 dbuf_loan_arcbuf(dmu_buf_impl_t *db) 440 { 441 arc_buf_t *abuf; 442 443 mutex_enter(&db->db_mtx); 444 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) { 445 int blksz = db->db.db_size; 446 spa_t *spa = db->db_objset->os_spa; 447 448 mutex_exit(&db->db_mtx); 449 abuf = arc_loan_buf(spa, blksz); 450 bcopy(db->db.db_data, abuf->b_data, blksz); 451 } else { 452 abuf = db->db_buf; 453 arc_loan_inuse_buf(abuf, db); 454 dbuf_set_data(db, NULL); 455 mutex_exit(&db->db_mtx); 456 } 457 return (abuf); 458 } 459 460 uint64_t 461 dbuf_whichblock(dnode_t *dn, uint64_t offset) 462 { 463 if (dn->dn_datablkshift) { 464 return (offset >> dn->dn_datablkshift); 465 } else { 466 ASSERT3U(offset, <, dn->dn_datablksz); 467 return (0); 468 } 469 } 470 471 static void 472 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb) 473 { 474 dmu_buf_impl_t *db = vdb; 475 476 mutex_enter(&db->db_mtx); 477 ASSERT3U(db->db_state, ==, DB_READ); 478 /* 479 * All reads are synchronous, so we must have a hold on the dbuf 480 */ 481 ASSERT(refcount_count(&db->db_holds) > 0); 482 ASSERT(db->db_buf == NULL); 483 ASSERT(db->db.db_data == NULL); 484 if (db->db_level == 0 && db->db_freed_in_flight) { 485 /* we were freed in flight; disregard any error */ 486 arc_release(buf, db); 487 bzero(buf->b_data, db->db.db_size); 488 arc_buf_freeze(buf); 489 db->db_freed_in_flight = FALSE; 490 dbuf_set_data(db, buf); 491 db->db_state = DB_CACHED; 492 } else if (zio == NULL || zio->io_error == 0) { 493 dbuf_set_data(db, buf); 494 db->db_state = DB_CACHED; 495 } else { 496 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 497 ASSERT3P(db->db_buf, ==, NULL); 498 VERIFY(arc_buf_remove_ref(buf, db)); 499 db->db_state = DB_UNCACHED; 500 } 501 cv_broadcast(&db->db_changed); 502 dbuf_rele_and_unlock(db, NULL); 503 } 504 505 static void 506 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags) 507 { 508 dnode_t *dn; 509 zbookmark_phys_t zb; 510 uint32_t aflags = ARC_NOWAIT; 511 512 DB_DNODE_ENTER(db); 513 dn = DB_DNODE(db); 514 ASSERT(!refcount_is_zero(&db->db_holds)); 515 /* We need the struct_rwlock to prevent db_blkptr from changing. */ 516 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 517 ASSERT(MUTEX_HELD(&db->db_mtx)); 518 ASSERT(db->db_state == DB_UNCACHED); 519 ASSERT(db->db_buf == NULL); 520 521 if (db->db_blkid == DMU_BONUS_BLKID) { 522 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen); 523 524 ASSERT3U(bonuslen, <=, db->db.db_size); 525 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN); 526 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 527 if (bonuslen < DN_MAX_BONUSLEN) 528 bzero(db->db.db_data, DN_MAX_BONUSLEN); 529 if (bonuslen) 530 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen); 531 DB_DNODE_EXIT(db); 532 db->db_state = DB_CACHED; 533 mutex_exit(&db->db_mtx); 534 return; 535 } 536 537 /* 538 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync() 539 * processes the delete record and clears the bp while we are waiting 540 * for the dn_mtx (resulting in a "no" from block_freed). 541 */ 542 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) || 543 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) || 544 BP_IS_HOLE(db->db_blkptr)))) { 545 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 546 547 DB_DNODE_EXIT(db); 548 dbuf_set_data(db, arc_buf_alloc(db->db_objset->os_spa, 549 db->db.db_size, db, type)); 550 bzero(db->db.db_data, db->db.db_size); 551 db->db_state = DB_CACHED; 552 *flags |= DB_RF_CACHED; 553 mutex_exit(&db->db_mtx); 554 return; 555 } 556 557 DB_DNODE_EXIT(db); 558 559 db->db_state = DB_READ; 560 mutex_exit(&db->db_mtx); 561 562 if (DBUF_IS_L2CACHEABLE(db)) 563 aflags |= ARC_L2CACHE; 564 if (DBUF_IS_L2COMPRESSIBLE(db)) 565 aflags |= ARC_L2COMPRESS; 566 567 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ? 568 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET, 569 db->db.db_object, db->db_level, db->db_blkid); 570 571 dbuf_add_ref(db, NULL); 572 573 (void) arc_read(zio, db->db_objset->os_spa, db->db_blkptr, 574 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ, 575 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED, 576 &aflags, &zb); 577 if (aflags & ARC_CACHED) 578 *flags |= DB_RF_CACHED; 579 } 580 581 int 582 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) 583 { 584 int err = 0; 585 boolean_t havepzio = (zio != NULL); 586 boolean_t prefetch; 587 dnode_t *dn; 588 589 /* 590 * We don't have to hold the mutex to check db_state because it 591 * can't be freed while we have a hold on the buffer. 592 */ 593 ASSERT(!refcount_is_zero(&db->db_holds)); 594 595 if (db->db_state == DB_NOFILL) 596 return (SET_ERROR(EIO)); 597 598 DB_DNODE_ENTER(db); 599 dn = DB_DNODE(db); 600 if ((flags & DB_RF_HAVESTRUCT) == 0) 601 rw_enter(&dn->dn_struct_rwlock, RW_READER); 602 603 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 604 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL && 605 DBUF_IS_CACHEABLE(db); 606 607 mutex_enter(&db->db_mtx); 608 if (db->db_state == DB_CACHED) { 609 mutex_exit(&db->db_mtx); 610 if (prefetch) 611 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 612 db->db.db_size, TRUE); 613 if ((flags & DB_RF_HAVESTRUCT) == 0) 614 rw_exit(&dn->dn_struct_rwlock); 615 DB_DNODE_EXIT(db); 616 } else if (db->db_state == DB_UNCACHED) { 617 spa_t *spa = dn->dn_objset->os_spa; 618 619 if (zio == NULL) 620 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL); 621 dbuf_read_impl(db, zio, &flags); 622 623 /* dbuf_read_impl has dropped db_mtx for us */ 624 625 if (prefetch) 626 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 627 db->db.db_size, flags & DB_RF_CACHED); 628 629 if ((flags & DB_RF_HAVESTRUCT) == 0) 630 rw_exit(&dn->dn_struct_rwlock); 631 DB_DNODE_EXIT(db); 632 633 if (!havepzio) 634 err = zio_wait(zio); 635 } else { 636 /* 637 * Another reader came in while the dbuf was in flight 638 * between UNCACHED and CACHED. Either a writer will finish 639 * writing the buffer (sending the dbuf to CACHED) or the 640 * first reader's request will reach the read_done callback 641 * and send the dbuf to CACHED. Otherwise, a failure 642 * occurred and the dbuf went to UNCACHED. 643 */ 644 mutex_exit(&db->db_mtx); 645 if (prefetch) 646 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 647 db->db.db_size, TRUE); 648 if ((flags & DB_RF_HAVESTRUCT) == 0) 649 rw_exit(&dn->dn_struct_rwlock); 650 DB_DNODE_EXIT(db); 651 652 /* Skip the wait per the caller's request. */ 653 mutex_enter(&db->db_mtx); 654 if ((flags & DB_RF_NEVERWAIT) == 0) { 655 while (db->db_state == DB_READ || 656 db->db_state == DB_FILL) { 657 ASSERT(db->db_state == DB_READ || 658 (flags & DB_RF_HAVESTRUCT) == 0); 659 DTRACE_PROBE2(blocked__read, dmu_buf_impl_t *, 660 db, zio_t *, zio); 661 cv_wait(&db->db_changed, &db->db_mtx); 662 } 663 if (db->db_state == DB_UNCACHED) 664 err = SET_ERROR(EIO); 665 } 666 mutex_exit(&db->db_mtx); 667 } 668 669 ASSERT(err || havepzio || db->db_state == DB_CACHED); 670 return (err); 671 } 672 673 static void 674 dbuf_noread(dmu_buf_impl_t *db) 675 { 676 ASSERT(!refcount_is_zero(&db->db_holds)); 677 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 678 mutex_enter(&db->db_mtx); 679 while (db->db_state == DB_READ || db->db_state == DB_FILL) 680 cv_wait(&db->db_changed, &db->db_mtx); 681 if (db->db_state == DB_UNCACHED) { 682 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 683 spa_t *spa = db->db_objset->os_spa; 684 685 ASSERT(db->db_buf == NULL); 686 ASSERT(db->db.db_data == NULL); 687 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type)); 688 db->db_state = DB_FILL; 689 } else if (db->db_state == DB_NOFILL) { 690 dbuf_set_data(db, NULL); 691 } else { 692 ASSERT3U(db->db_state, ==, DB_CACHED); 693 } 694 mutex_exit(&db->db_mtx); 695 } 696 697 /* 698 * This is our just-in-time copy function. It makes a copy of 699 * buffers, that have been modified in a previous transaction 700 * group, before we modify them in the current active group. 701 * 702 * This function is used in two places: when we are dirtying a 703 * buffer for the first time in a txg, and when we are freeing 704 * a range in a dnode that includes this buffer. 705 * 706 * Note that when we are called from dbuf_free_range() we do 707 * not put a hold on the buffer, we just traverse the active 708 * dbuf list for the dnode. 709 */ 710 static void 711 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg) 712 { 713 dbuf_dirty_record_t *dr = db->db_last_dirty; 714 715 ASSERT(MUTEX_HELD(&db->db_mtx)); 716 ASSERT(db->db.db_data != NULL); 717 ASSERT(db->db_level == 0); 718 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT); 719 720 if (dr == NULL || 721 (dr->dt.dl.dr_data != 722 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf))) 723 return; 724 725 /* 726 * If the last dirty record for this dbuf has not yet synced 727 * and its referencing the dbuf data, either: 728 * reset the reference to point to a new copy, 729 * or (if there a no active holders) 730 * just null out the current db_data pointer. 731 */ 732 ASSERT(dr->dr_txg >= txg - 2); 733 if (db->db_blkid == DMU_BONUS_BLKID) { 734 /* Note that the data bufs here are zio_bufs */ 735 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN); 736 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 737 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN); 738 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) { 739 int size = db->db.db_size; 740 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 741 spa_t *spa = db->db_objset->os_spa; 742 743 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type); 744 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size); 745 } else { 746 dbuf_set_data(db, NULL); 747 } 748 } 749 750 void 751 dbuf_unoverride(dbuf_dirty_record_t *dr) 752 { 753 dmu_buf_impl_t *db = dr->dr_dbuf; 754 blkptr_t *bp = &dr->dt.dl.dr_overridden_by; 755 uint64_t txg = dr->dr_txg; 756 757 ASSERT(MUTEX_HELD(&db->db_mtx)); 758 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC); 759 ASSERT(db->db_level == 0); 760 761 if (db->db_blkid == DMU_BONUS_BLKID || 762 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN) 763 return; 764 765 ASSERT(db->db_data_pending != dr); 766 767 /* free this block */ 768 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite) 769 zio_free(db->db_objset->os_spa, txg, bp); 770 771 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 772 dr->dt.dl.dr_nopwrite = B_FALSE; 773 774 /* 775 * Release the already-written buffer, so we leave it in 776 * a consistent dirty state. Note that all callers are 777 * modifying the buffer, so they will immediately do 778 * another (redundant) arc_release(). Therefore, leave 779 * the buf thawed to save the effort of freezing & 780 * immediately re-thawing it. 781 */ 782 arc_release(dr->dt.dl.dr_data, db); 783 } 784 785 /* 786 * Evict (if its unreferenced) or clear (if its referenced) any level-0 787 * data blocks in the free range, so that any future readers will find 788 * empty blocks. 789 * 790 * This is a no-op if the dataset is in the middle of an incremental 791 * receive; see comment below for details. 792 */ 793 void 794 dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, 795 dmu_tx_t *tx) 796 { 797 dmu_buf_impl_t *db, *db_next, db_search; 798 uint64_t txg = tx->tx_txg; 799 avl_index_t where; 800 801 if (end_blkid > dn->dn_maxblkid && (end_blkid != DMU_SPILL_BLKID)) 802 end_blkid = dn->dn_maxblkid; 803 dprintf_dnode(dn, "start=%llu end=%llu\n", start_blkid, end_blkid); 804 805 db_search.db_level = 0; 806 db_search.db_blkid = start_blkid; 807 db_search.db_state = DB_SEARCH; 808 809 mutex_enter(&dn->dn_dbufs_mtx); 810 if (start_blkid >= dn->dn_unlisted_l0_blkid) { 811 /* There can't be any dbufs in this range; no need to search. */ 812 #ifdef DEBUG 813 db = avl_find(&dn->dn_dbufs, &db_search, &where); 814 ASSERT3P(db, ==, NULL); 815 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 816 ASSERT(db == NULL || db->db_level > 0); 817 #endif 818 mutex_exit(&dn->dn_dbufs_mtx); 819 return; 820 } else if (dmu_objset_is_receiving(dn->dn_objset)) { 821 /* 822 * If we are receiving, we expect there to be no dbufs in 823 * the range to be freed, because receive modifies each 824 * block at most once, and in offset order. If this is 825 * not the case, it can lead to performance problems, 826 * so note that we unexpectedly took the slow path. 827 */ 828 atomic_inc_64(&zfs_free_range_recv_miss); 829 } 830 831 db = avl_find(&dn->dn_dbufs, &db_search, &where); 832 ASSERT3P(db, ==, NULL); 833 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 834 835 for (; db != NULL; db = db_next) { 836 db_next = AVL_NEXT(&dn->dn_dbufs, db); 837 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 838 839 if (db->db_level != 0 || db->db_blkid > end_blkid) { 840 break; 841 } 842 ASSERT3U(db->db_blkid, >=, start_blkid); 843 844 /* found a level 0 buffer in the range */ 845 mutex_enter(&db->db_mtx); 846 if (dbuf_undirty(db, tx)) { 847 /* mutex has been dropped and dbuf destroyed */ 848 continue; 849 } 850 851 if (db->db_state == DB_UNCACHED || 852 db->db_state == DB_NOFILL || 853 db->db_state == DB_EVICTING) { 854 ASSERT(db->db.db_data == NULL); 855 mutex_exit(&db->db_mtx); 856 continue; 857 } 858 if (db->db_state == DB_READ || db->db_state == DB_FILL) { 859 /* will be handled in dbuf_read_done or dbuf_rele */ 860 db->db_freed_in_flight = TRUE; 861 mutex_exit(&db->db_mtx); 862 continue; 863 } 864 if (refcount_count(&db->db_holds) == 0) { 865 ASSERT(db->db_buf); 866 dbuf_clear(db); 867 continue; 868 } 869 /* The dbuf is referenced */ 870 871 if (db->db_last_dirty != NULL) { 872 dbuf_dirty_record_t *dr = db->db_last_dirty; 873 874 if (dr->dr_txg == txg) { 875 /* 876 * This buffer is "in-use", re-adjust the file 877 * size to reflect that this buffer may 878 * contain new data when we sync. 879 */ 880 if (db->db_blkid != DMU_SPILL_BLKID && 881 db->db_blkid > dn->dn_maxblkid) 882 dn->dn_maxblkid = db->db_blkid; 883 dbuf_unoverride(dr); 884 } else { 885 /* 886 * This dbuf is not dirty in the open context. 887 * Either uncache it (if its not referenced in 888 * the open context) or reset its contents to 889 * empty. 890 */ 891 dbuf_fix_old_data(db, txg); 892 } 893 } 894 /* clear the contents if its cached */ 895 if (db->db_state == DB_CACHED) { 896 ASSERT(db->db.db_data != NULL); 897 arc_release(db->db_buf, db); 898 bzero(db->db.db_data, db->db.db_size); 899 arc_buf_freeze(db->db_buf); 900 } 901 902 mutex_exit(&db->db_mtx); 903 } 904 mutex_exit(&dn->dn_dbufs_mtx); 905 } 906 907 static int 908 dbuf_block_freeable(dmu_buf_impl_t *db) 909 { 910 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset; 911 uint64_t birth_txg = 0; 912 913 /* 914 * We don't need any locking to protect db_blkptr: 915 * If it's syncing, then db_last_dirty will be set 916 * so we'll ignore db_blkptr. 917 * 918 * This logic ensures that only block births for 919 * filled blocks are considered. 920 */ 921 ASSERT(MUTEX_HELD(&db->db_mtx)); 922 if (db->db_last_dirty && (db->db_blkptr == NULL || 923 !BP_IS_HOLE(db->db_blkptr))) { 924 birth_txg = db->db_last_dirty->dr_txg; 925 } else if (db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr)) { 926 birth_txg = db->db_blkptr->blk_birth; 927 } 928 929 /* 930 * If this block don't exist or is in a snapshot, it can't be freed. 931 * Don't pass the bp to dsl_dataset_block_freeable() since we 932 * are holding the db_mtx lock and might deadlock if we are 933 * prefetching a dedup-ed block. 934 */ 935 if (birth_txg != 0) 936 return (ds == NULL || 937 dsl_dataset_block_freeable(ds, NULL, birth_txg)); 938 else 939 return (B_FALSE); 940 } 941 942 void 943 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx) 944 { 945 arc_buf_t *buf, *obuf; 946 int osize = db->db.db_size; 947 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 948 dnode_t *dn; 949 950 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 951 952 DB_DNODE_ENTER(db); 953 dn = DB_DNODE(db); 954 955 /* XXX does *this* func really need the lock? */ 956 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 957 958 /* 959 * This call to dmu_buf_will_dirty() with the dn_struct_rwlock held 960 * is OK, because there can be no other references to the db 961 * when we are changing its size, so no concurrent DB_FILL can 962 * be happening. 963 */ 964 /* 965 * XXX we should be doing a dbuf_read, checking the return 966 * value and returning that up to our callers 967 */ 968 dmu_buf_will_dirty(&db->db, tx); 969 970 /* create the data buffer for the new block */ 971 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type); 972 973 /* copy old block data to the new block */ 974 obuf = db->db_buf; 975 bcopy(obuf->b_data, buf->b_data, MIN(osize, size)); 976 /* zero the remainder */ 977 if (size > osize) 978 bzero((uint8_t *)buf->b_data + osize, size - osize); 979 980 mutex_enter(&db->db_mtx); 981 dbuf_set_data(db, buf); 982 VERIFY(arc_buf_remove_ref(obuf, db)); 983 db->db.db_size = size; 984 985 if (db->db_level == 0) { 986 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 987 db->db_last_dirty->dt.dl.dr_data = buf; 988 } 989 mutex_exit(&db->db_mtx); 990 991 dnode_willuse_space(dn, size-osize, tx); 992 DB_DNODE_EXIT(db); 993 } 994 995 void 996 dbuf_release_bp(dmu_buf_impl_t *db) 997 { 998 objset_t *os = db->db_objset; 999 1000 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os))); 1001 ASSERT(arc_released(os->os_phys_buf) || 1002 list_link_active(&os->os_dsl_dataset->ds_synced_link)); 1003 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf)); 1004 1005 (void) arc_release(db->db_buf, db); 1006 } 1007 1008 dbuf_dirty_record_t * 1009 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1010 { 1011 dnode_t *dn; 1012 objset_t *os; 1013 dbuf_dirty_record_t **drp, *dr; 1014 int drop_struct_lock = FALSE; 1015 boolean_t do_free_accounting = B_FALSE; 1016 int txgoff = tx->tx_txg & TXG_MASK; 1017 1018 ASSERT(tx->tx_txg != 0); 1019 ASSERT(!refcount_is_zero(&db->db_holds)); 1020 DMU_TX_DIRTY_BUF(tx, db); 1021 1022 DB_DNODE_ENTER(db); 1023 dn = DB_DNODE(db); 1024 /* 1025 * Shouldn't dirty a regular buffer in syncing context. Private 1026 * objects may be dirtied in syncing context, but only if they 1027 * were already pre-dirtied in open context. 1028 */ 1029 ASSERT(!dmu_tx_is_syncing(tx) || 1030 BP_IS_HOLE(dn->dn_objset->os_rootbp) || 1031 DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1032 dn->dn_objset->os_dsl_dataset == NULL); 1033 /* 1034 * We make this assert for private objects as well, but after we 1035 * check if we're already dirty. They are allowed to re-dirty 1036 * in syncing context. 1037 */ 1038 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1039 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1040 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1041 1042 mutex_enter(&db->db_mtx); 1043 /* 1044 * XXX make this true for indirects too? The problem is that 1045 * transactions created with dmu_tx_create_assigned() from 1046 * syncing context don't bother holding ahead. 1047 */ 1048 ASSERT(db->db_level != 0 || 1049 db->db_state == DB_CACHED || db->db_state == DB_FILL || 1050 db->db_state == DB_NOFILL); 1051 1052 mutex_enter(&dn->dn_mtx); 1053 /* 1054 * Don't set dirtyctx to SYNC if we're just modifying this as we 1055 * initialize the objset. 1056 */ 1057 if (dn->dn_dirtyctx == DN_UNDIRTIED && 1058 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) { 1059 dn->dn_dirtyctx = 1060 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN); 1061 ASSERT(dn->dn_dirtyctx_firstset == NULL); 1062 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP); 1063 } 1064 mutex_exit(&dn->dn_mtx); 1065 1066 if (db->db_blkid == DMU_SPILL_BLKID) 1067 dn->dn_have_spill = B_TRUE; 1068 1069 /* 1070 * If this buffer is already dirty, we're done. 1071 */ 1072 drp = &db->db_last_dirty; 1073 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg || 1074 db->db.db_object == DMU_META_DNODE_OBJECT); 1075 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg) 1076 drp = &dr->dr_next; 1077 if (dr && dr->dr_txg == tx->tx_txg) { 1078 DB_DNODE_EXIT(db); 1079 1080 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) { 1081 /* 1082 * If this buffer has already been written out, 1083 * we now need to reset its state. 1084 */ 1085 dbuf_unoverride(dr); 1086 if (db->db.db_object != DMU_META_DNODE_OBJECT && 1087 db->db_state != DB_NOFILL) 1088 arc_buf_thaw(db->db_buf); 1089 } 1090 mutex_exit(&db->db_mtx); 1091 return (dr); 1092 } 1093 1094 /* 1095 * Only valid if not already dirty. 1096 */ 1097 ASSERT(dn->dn_object == 0 || 1098 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1099 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1100 1101 ASSERT3U(dn->dn_nlevels, >, db->db_level); 1102 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) || 1103 dn->dn_phys->dn_nlevels > db->db_level || 1104 dn->dn_next_nlevels[txgoff] > db->db_level || 1105 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level || 1106 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level); 1107 1108 /* 1109 * We should only be dirtying in syncing context if it's the 1110 * mos or we're initializing the os or it's a special object. 1111 * However, we are allowed to dirty in syncing context provided 1112 * we already dirtied it in open context. Hence we must make 1113 * this assertion only if we're not already dirty. 1114 */ 1115 os = dn->dn_objset; 1116 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1117 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp)); 1118 ASSERT(db->db.db_size != 0); 1119 1120 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1121 1122 if (db->db_blkid != DMU_BONUS_BLKID) { 1123 /* 1124 * Update the accounting. 1125 * Note: we delay "free accounting" until after we drop 1126 * the db_mtx. This keeps us from grabbing other locks 1127 * (and possibly deadlocking) in bp_get_dsize() while 1128 * also holding the db_mtx. 1129 */ 1130 dnode_willuse_space(dn, db->db.db_size, tx); 1131 do_free_accounting = dbuf_block_freeable(db); 1132 } 1133 1134 /* 1135 * If this buffer is dirty in an old transaction group we need 1136 * to make a copy of it so that the changes we make in this 1137 * transaction group won't leak out when we sync the older txg. 1138 */ 1139 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP); 1140 if (db->db_level == 0) { 1141 void *data_old = db->db_buf; 1142 1143 if (db->db_state != DB_NOFILL) { 1144 if (db->db_blkid == DMU_BONUS_BLKID) { 1145 dbuf_fix_old_data(db, tx->tx_txg); 1146 data_old = db->db.db_data; 1147 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) { 1148 /* 1149 * Release the data buffer from the cache so 1150 * that we can modify it without impacting 1151 * possible other users of this cached data 1152 * block. Note that indirect blocks and 1153 * private objects are not released until the 1154 * syncing state (since they are only modified 1155 * then). 1156 */ 1157 arc_release(db->db_buf, db); 1158 dbuf_fix_old_data(db, tx->tx_txg); 1159 data_old = db->db_buf; 1160 } 1161 ASSERT(data_old != NULL); 1162 } 1163 dr->dt.dl.dr_data = data_old; 1164 } else { 1165 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL); 1166 list_create(&dr->dt.di.dr_children, 1167 sizeof (dbuf_dirty_record_t), 1168 offsetof(dbuf_dirty_record_t, dr_dirty_node)); 1169 } 1170 if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL) 1171 dr->dr_accounted = db->db.db_size; 1172 dr->dr_dbuf = db; 1173 dr->dr_txg = tx->tx_txg; 1174 dr->dr_next = *drp; 1175 *drp = dr; 1176 1177 /* 1178 * We could have been freed_in_flight between the dbuf_noread 1179 * and dbuf_dirty. We win, as though the dbuf_noread() had 1180 * happened after the free. 1181 */ 1182 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1183 db->db_blkid != DMU_SPILL_BLKID) { 1184 mutex_enter(&dn->dn_mtx); 1185 if (dn->dn_free_ranges[txgoff] != NULL) { 1186 range_tree_clear(dn->dn_free_ranges[txgoff], 1187 db->db_blkid, 1); 1188 } 1189 mutex_exit(&dn->dn_mtx); 1190 db->db_freed_in_flight = FALSE; 1191 } 1192 1193 /* 1194 * This buffer is now part of this txg 1195 */ 1196 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg); 1197 db->db_dirtycnt += 1; 1198 ASSERT3U(db->db_dirtycnt, <=, 3); 1199 1200 mutex_exit(&db->db_mtx); 1201 1202 if (db->db_blkid == DMU_BONUS_BLKID || 1203 db->db_blkid == DMU_SPILL_BLKID) { 1204 mutex_enter(&dn->dn_mtx); 1205 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1206 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1207 mutex_exit(&dn->dn_mtx); 1208 dnode_setdirty(dn, tx); 1209 DB_DNODE_EXIT(db); 1210 return (dr); 1211 } else if (do_free_accounting) { 1212 blkptr_t *bp = db->db_blkptr; 1213 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ? 1214 bp_get_dsize(os->os_spa, bp) : db->db.db_size; 1215 /* 1216 * This is only a guess -- if the dbuf is dirty 1217 * in a previous txg, we don't know how much 1218 * space it will use on disk yet. We should 1219 * really have the struct_rwlock to access 1220 * db_blkptr, but since this is just a guess, 1221 * it's OK if we get an odd answer. 1222 */ 1223 ddt_prefetch(os->os_spa, bp); 1224 dnode_willuse_space(dn, -willfree, tx); 1225 } 1226 1227 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 1228 rw_enter(&dn->dn_struct_rwlock, RW_READER); 1229 drop_struct_lock = TRUE; 1230 } 1231 1232 if (db->db_level == 0) { 1233 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock); 1234 ASSERT(dn->dn_maxblkid >= db->db_blkid); 1235 } 1236 1237 if (db->db_level+1 < dn->dn_nlevels) { 1238 dmu_buf_impl_t *parent = db->db_parent; 1239 dbuf_dirty_record_t *di; 1240 int parent_held = FALSE; 1241 1242 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) { 1243 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1244 1245 parent = dbuf_hold_level(dn, db->db_level+1, 1246 db->db_blkid >> epbs, FTAG); 1247 ASSERT(parent != NULL); 1248 parent_held = TRUE; 1249 } 1250 if (drop_struct_lock) 1251 rw_exit(&dn->dn_struct_rwlock); 1252 ASSERT3U(db->db_level+1, ==, parent->db_level); 1253 di = dbuf_dirty(parent, tx); 1254 if (parent_held) 1255 dbuf_rele(parent, FTAG); 1256 1257 mutex_enter(&db->db_mtx); 1258 /* 1259 * Since we've dropped the mutex, it's possible that 1260 * dbuf_undirty() might have changed this out from under us. 1261 */ 1262 if (db->db_last_dirty == dr || 1263 dn->dn_object == DMU_META_DNODE_OBJECT) { 1264 mutex_enter(&di->dt.di.dr_mtx); 1265 ASSERT3U(di->dr_txg, ==, tx->tx_txg); 1266 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1267 list_insert_tail(&di->dt.di.dr_children, dr); 1268 mutex_exit(&di->dt.di.dr_mtx); 1269 dr->dr_parent = di; 1270 } 1271 mutex_exit(&db->db_mtx); 1272 } else { 1273 ASSERT(db->db_level+1 == dn->dn_nlevels); 1274 ASSERT(db->db_blkid < dn->dn_nblkptr); 1275 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf); 1276 mutex_enter(&dn->dn_mtx); 1277 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1278 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1279 mutex_exit(&dn->dn_mtx); 1280 if (drop_struct_lock) 1281 rw_exit(&dn->dn_struct_rwlock); 1282 } 1283 1284 dnode_setdirty(dn, tx); 1285 DB_DNODE_EXIT(db); 1286 return (dr); 1287 } 1288 1289 /* 1290 * Undirty a buffer in the transaction group referenced by the given 1291 * transaction. Return whether this evicted the dbuf. 1292 */ 1293 static boolean_t 1294 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1295 { 1296 dnode_t *dn; 1297 uint64_t txg = tx->tx_txg; 1298 dbuf_dirty_record_t *dr, **drp; 1299 1300 ASSERT(txg != 0); 1301 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1302 ASSERT0(db->db_level); 1303 ASSERT(MUTEX_HELD(&db->db_mtx)); 1304 1305 /* 1306 * If this buffer is not dirty, we're done. 1307 */ 1308 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next) 1309 if (dr->dr_txg <= txg) 1310 break; 1311 if (dr == NULL || dr->dr_txg < txg) 1312 return (B_FALSE); 1313 ASSERT(dr->dr_txg == txg); 1314 ASSERT(dr->dr_dbuf == db); 1315 1316 DB_DNODE_ENTER(db); 1317 dn = DB_DNODE(db); 1318 1319 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1320 1321 ASSERT(db->db.db_size != 0); 1322 1323 /* 1324 * Any space we accounted for in dp_dirty_* will be cleaned up by 1325 * dsl_pool_sync(). This is relatively rare so the discrepancy 1326 * is not a big deal. 1327 */ 1328 1329 *drp = dr->dr_next; 1330 1331 /* 1332 * Note that there are three places in dbuf_dirty() 1333 * where this dirty record may be put on a list. 1334 * Make sure to do a list_remove corresponding to 1335 * every one of those list_insert calls. 1336 */ 1337 if (dr->dr_parent) { 1338 mutex_enter(&dr->dr_parent->dt.di.dr_mtx); 1339 list_remove(&dr->dr_parent->dt.di.dr_children, dr); 1340 mutex_exit(&dr->dr_parent->dt.di.dr_mtx); 1341 } else if (db->db_blkid == DMU_SPILL_BLKID || 1342 db->db_level+1 == dn->dn_nlevels) { 1343 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf); 1344 mutex_enter(&dn->dn_mtx); 1345 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr); 1346 mutex_exit(&dn->dn_mtx); 1347 } 1348 DB_DNODE_EXIT(db); 1349 1350 if (db->db_state != DB_NOFILL) { 1351 dbuf_unoverride(dr); 1352 1353 ASSERT(db->db_buf != NULL); 1354 ASSERT(dr->dt.dl.dr_data != NULL); 1355 if (dr->dt.dl.dr_data != db->db_buf) 1356 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db)); 1357 } 1358 1359 if (db->db_level != 0) { 1360 mutex_destroy(&dr->dt.di.dr_mtx); 1361 list_destroy(&dr->dt.di.dr_children); 1362 } 1363 1364 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 1365 1366 ASSERT(db->db_dirtycnt > 0); 1367 db->db_dirtycnt -= 1; 1368 1369 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) { 1370 arc_buf_t *buf = db->db_buf; 1371 1372 ASSERT(db->db_state == DB_NOFILL || arc_released(buf)); 1373 dbuf_set_data(db, NULL); 1374 VERIFY(arc_buf_remove_ref(buf, db)); 1375 dbuf_evict(db); 1376 return (B_TRUE); 1377 } 1378 1379 return (B_FALSE); 1380 } 1381 1382 void 1383 dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx) 1384 { 1385 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1386 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH; 1387 1388 ASSERT(tx->tx_txg != 0); 1389 ASSERT(!refcount_is_zero(&db->db_holds)); 1390 1391 DB_DNODE_ENTER(db); 1392 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock)) 1393 rf |= DB_RF_HAVESTRUCT; 1394 DB_DNODE_EXIT(db); 1395 (void) dbuf_read(db, NULL, rf); 1396 (void) dbuf_dirty(db, tx); 1397 } 1398 1399 void 1400 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1401 { 1402 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1403 1404 db->db_state = DB_NOFILL; 1405 1406 dmu_buf_will_fill(db_fake, tx); 1407 } 1408 1409 void 1410 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1411 { 1412 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1413 1414 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1415 ASSERT(tx->tx_txg != 0); 1416 ASSERT(db->db_level == 0); 1417 ASSERT(!refcount_is_zero(&db->db_holds)); 1418 1419 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT || 1420 dmu_tx_private_ok(tx)); 1421 1422 dbuf_noread(db); 1423 (void) dbuf_dirty(db, tx); 1424 } 1425 1426 #pragma weak dmu_buf_fill_done = dbuf_fill_done 1427 /* ARGSUSED */ 1428 void 1429 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx) 1430 { 1431 mutex_enter(&db->db_mtx); 1432 DBUF_VERIFY(db); 1433 1434 if (db->db_state == DB_FILL) { 1435 if (db->db_level == 0 && db->db_freed_in_flight) { 1436 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1437 /* we were freed while filling */ 1438 /* XXX dbuf_undirty? */ 1439 bzero(db->db.db_data, db->db.db_size); 1440 db->db_freed_in_flight = FALSE; 1441 } 1442 db->db_state = DB_CACHED; 1443 cv_broadcast(&db->db_changed); 1444 } 1445 mutex_exit(&db->db_mtx); 1446 } 1447 1448 void 1449 dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data, 1450 bp_embedded_type_t etype, enum zio_compress comp, 1451 int uncompressed_size, int compressed_size, int byteorder, 1452 dmu_tx_t *tx) 1453 { 1454 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 1455 struct dirty_leaf *dl; 1456 dmu_object_type_t type; 1457 1458 DB_DNODE_ENTER(db); 1459 type = DB_DNODE(db)->dn_type; 1460 DB_DNODE_EXIT(db); 1461 1462 ASSERT0(db->db_level); 1463 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1464 1465 dmu_buf_will_not_fill(dbuf, tx); 1466 1467 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 1468 dl = &db->db_last_dirty->dt.dl; 1469 encode_embedded_bp_compressed(&dl->dr_overridden_by, 1470 data, comp, uncompressed_size, compressed_size); 1471 BPE_SET_ETYPE(&dl->dr_overridden_by, etype); 1472 BP_SET_TYPE(&dl->dr_overridden_by, type); 1473 BP_SET_LEVEL(&dl->dr_overridden_by, 0); 1474 BP_SET_BYTEORDER(&dl->dr_overridden_by, byteorder); 1475 1476 dl->dr_override_state = DR_OVERRIDDEN; 1477 dl->dr_overridden_by.blk_birth = db->db_last_dirty->dr_txg; 1478 } 1479 1480 /* 1481 * Directly assign a provided arc buf to a given dbuf if it's not referenced 1482 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf. 1483 */ 1484 void 1485 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx) 1486 { 1487 ASSERT(!refcount_is_zero(&db->db_holds)); 1488 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1489 ASSERT(db->db_level == 0); 1490 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA); 1491 ASSERT(buf != NULL); 1492 ASSERT(arc_buf_size(buf) == db->db.db_size); 1493 ASSERT(tx->tx_txg != 0); 1494 1495 arc_return_buf(buf, db); 1496 ASSERT(arc_released(buf)); 1497 1498 mutex_enter(&db->db_mtx); 1499 1500 while (db->db_state == DB_READ || db->db_state == DB_FILL) 1501 cv_wait(&db->db_changed, &db->db_mtx); 1502 1503 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED); 1504 1505 if (db->db_state == DB_CACHED && 1506 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) { 1507 mutex_exit(&db->db_mtx); 1508 (void) dbuf_dirty(db, tx); 1509 bcopy(buf->b_data, db->db.db_data, db->db.db_size); 1510 VERIFY(arc_buf_remove_ref(buf, db)); 1511 xuio_stat_wbuf_copied(); 1512 return; 1513 } 1514 1515 xuio_stat_wbuf_nocopy(); 1516 if (db->db_state == DB_CACHED) { 1517 dbuf_dirty_record_t *dr = db->db_last_dirty; 1518 1519 ASSERT(db->db_buf != NULL); 1520 if (dr != NULL && dr->dr_txg == tx->tx_txg) { 1521 ASSERT(dr->dt.dl.dr_data == db->db_buf); 1522 if (!arc_released(db->db_buf)) { 1523 ASSERT(dr->dt.dl.dr_override_state == 1524 DR_OVERRIDDEN); 1525 arc_release(db->db_buf, db); 1526 } 1527 dr->dt.dl.dr_data = buf; 1528 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1529 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) { 1530 arc_release(db->db_buf, db); 1531 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1532 } 1533 db->db_buf = NULL; 1534 } 1535 ASSERT(db->db_buf == NULL); 1536 dbuf_set_data(db, buf); 1537 db->db_state = DB_FILL; 1538 mutex_exit(&db->db_mtx); 1539 (void) dbuf_dirty(db, tx); 1540 dmu_buf_fill_done(&db->db, tx); 1541 } 1542 1543 /* 1544 * "Clear" the contents of this dbuf. This will mark the dbuf 1545 * EVICTING and clear *most* of its references. Unfortunately, 1546 * when we are not holding the dn_dbufs_mtx, we can't clear the 1547 * entry in the dn_dbufs list. We have to wait until dbuf_destroy() 1548 * in this case. For callers from the DMU we will usually see: 1549 * dbuf_clear()->arc_clear_callback()->dbuf_do_evict()->dbuf_destroy() 1550 * For the arc callback, we will usually see: 1551 * dbuf_do_evict()->dbuf_clear();dbuf_destroy() 1552 * Sometimes, though, we will get a mix of these two: 1553 * DMU: dbuf_clear()->arc_clear_callback() 1554 * ARC: dbuf_do_evict()->dbuf_destroy() 1555 * 1556 * This routine will dissociate the dbuf from the arc, by calling 1557 * arc_clear_callback(), but will not evict the data from the ARC. 1558 */ 1559 void 1560 dbuf_clear(dmu_buf_impl_t *db) 1561 { 1562 dnode_t *dn; 1563 dmu_buf_impl_t *parent = db->db_parent; 1564 dmu_buf_impl_t *dndb; 1565 boolean_t dbuf_gone = B_FALSE; 1566 1567 ASSERT(MUTEX_HELD(&db->db_mtx)); 1568 ASSERT(refcount_is_zero(&db->db_holds)); 1569 1570 dbuf_evict_user(db); 1571 1572 if (db->db_state == DB_CACHED) { 1573 ASSERT(db->db.db_data != NULL); 1574 if (db->db_blkid == DMU_BONUS_BLKID) { 1575 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN); 1576 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 1577 } 1578 db->db.db_data = NULL; 1579 db->db_state = DB_UNCACHED; 1580 } 1581 1582 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL); 1583 ASSERT(db->db_data_pending == NULL); 1584 1585 db->db_state = DB_EVICTING; 1586 db->db_blkptr = NULL; 1587 1588 DB_DNODE_ENTER(db); 1589 dn = DB_DNODE(db); 1590 dndb = dn->dn_dbuf; 1591 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) { 1592 avl_remove(&dn->dn_dbufs, db); 1593 atomic_dec_32(&dn->dn_dbufs_count); 1594 membar_producer(); 1595 DB_DNODE_EXIT(db); 1596 /* 1597 * Decrementing the dbuf count means that the hold corresponding 1598 * to the removed dbuf is no longer discounted in dnode_move(), 1599 * so the dnode cannot be moved until after we release the hold. 1600 * The membar_producer() ensures visibility of the decremented 1601 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually 1602 * release any lock. 1603 */ 1604 dnode_rele(dn, db); 1605 db->db_dnode_handle = NULL; 1606 } else { 1607 DB_DNODE_EXIT(db); 1608 } 1609 1610 if (db->db_buf) 1611 dbuf_gone = arc_clear_callback(db->db_buf); 1612 1613 if (!dbuf_gone) 1614 mutex_exit(&db->db_mtx); 1615 1616 /* 1617 * If this dbuf is referenced from an indirect dbuf, 1618 * decrement the ref count on the indirect dbuf. 1619 */ 1620 if (parent && parent != dndb) 1621 dbuf_rele(parent, db); 1622 } 1623 1624 static int 1625 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, 1626 dmu_buf_impl_t **parentp, blkptr_t **bpp) 1627 { 1628 int nlevels, epbs; 1629 1630 *parentp = NULL; 1631 *bpp = NULL; 1632 1633 ASSERT(blkid != DMU_BONUS_BLKID); 1634 1635 if (blkid == DMU_SPILL_BLKID) { 1636 mutex_enter(&dn->dn_mtx); 1637 if (dn->dn_have_spill && 1638 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) 1639 *bpp = &dn->dn_phys->dn_spill; 1640 else 1641 *bpp = NULL; 1642 dbuf_add_ref(dn->dn_dbuf, NULL); 1643 *parentp = dn->dn_dbuf; 1644 mutex_exit(&dn->dn_mtx); 1645 return (0); 1646 } 1647 1648 if (dn->dn_phys->dn_nlevels == 0) 1649 nlevels = 1; 1650 else 1651 nlevels = dn->dn_phys->dn_nlevels; 1652 1653 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1654 1655 ASSERT3U(level * epbs, <, 64); 1656 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1657 if (level >= nlevels || 1658 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) { 1659 /* the buffer has no parent yet */ 1660 return (SET_ERROR(ENOENT)); 1661 } else if (level < nlevels-1) { 1662 /* this block is referenced from an indirect block */ 1663 int err = dbuf_hold_impl(dn, level+1, 1664 blkid >> epbs, fail_sparse, NULL, parentp); 1665 if (err) 1666 return (err); 1667 err = dbuf_read(*parentp, NULL, 1668 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL)); 1669 if (err) { 1670 dbuf_rele(*parentp, NULL); 1671 *parentp = NULL; 1672 return (err); 1673 } 1674 *bpp = ((blkptr_t *)(*parentp)->db.db_data) + 1675 (blkid & ((1ULL << epbs) - 1)); 1676 return (0); 1677 } else { 1678 /* the block is referenced from the dnode */ 1679 ASSERT3U(level, ==, nlevels-1); 1680 ASSERT(dn->dn_phys->dn_nblkptr == 0 || 1681 blkid < dn->dn_phys->dn_nblkptr); 1682 if (dn->dn_dbuf) { 1683 dbuf_add_ref(dn->dn_dbuf, NULL); 1684 *parentp = dn->dn_dbuf; 1685 } 1686 *bpp = &dn->dn_phys->dn_blkptr[blkid]; 1687 return (0); 1688 } 1689 } 1690 1691 static dmu_buf_impl_t * 1692 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid, 1693 dmu_buf_impl_t *parent, blkptr_t *blkptr) 1694 { 1695 objset_t *os = dn->dn_objset; 1696 dmu_buf_impl_t *db, *odb; 1697 1698 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1699 ASSERT(dn->dn_type != DMU_OT_NONE); 1700 1701 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP); 1702 1703 db->db_objset = os; 1704 db->db.db_object = dn->dn_object; 1705 db->db_level = level; 1706 db->db_blkid = blkid; 1707 db->db_last_dirty = NULL; 1708 db->db_dirtycnt = 0; 1709 db->db_dnode_handle = dn->dn_handle; 1710 db->db_parent = parent; 1711 db->db_blkptr = blkptr; 1712 1713 db->db_user_ptr = NULL; 1714 db->db_evict_func = NULL; 1715 db->db_immediate_evict = 0; 1716 db->db_freed_in_flight = 0; 1717 1718 if (blkid == DMU_BONUS_BLKID) { 1719 ASSERT3P(parent, ==, dn->dn_dbuf); 1720 db->db.db_size = DN_MAX_BONUSLEN - 1721 (dn->dn_nblkptr-1) * sizeof (blkptr_t); 1722 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 1723 db->db.db_offset = DMU_BONUS_BLKID; 1724 db->db_state = DB_UNCACHED; 1725 /* the bonus dbuf is not placed in the hash table */ 1726 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1727 return (db); 1728 } else if (blkid == DMU_SPILL_BLKID) { 1729 db->db.db_size = (blkptr != NULL) ? 1730 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE; 1731 db->db.db_offset = 0; 1732 } else { 1733 int blocksize = 1734 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz; 1735 db->db.db_size = blocksize; 1736 db->db.db_offset = db->db_blkid * blocksize; 1737 } 1738 1739 /* 1740 * Hold the dn_dbufs_mtx while we get the new dbuf 1741 * in the hash table *and* added to the dbufs list. 1742 * This prevents a possible deadlock with someone 1743 * trying to look up this dbuf before its added to the 1744 * dn_dbufs list. 1745 */ 1746 mutex_enter(&dn->dn_dbufs_mtx); 1747 db->db_state = DB_EVICTING; 1748 if ((odb = dbuf_hash_insert(db)) != NULL) { 1749 /* someone else inserted it first */ 1750 kmem_cache_free(dbuf_cache, db); 1751 mutex_exit(&dn->dn_dbufs_mtx); 1752 return (odb); 1753 } 1754 avl_add(&dn->dn_dbufs, db); 1755 if (db->db_level == 0 && db->db_blkid >= 1756 dn->dn_unlisted_l0_blkid) 1757 dn->dn_unlisted_l0_blkid = db->db_blkid + 1; 1758 db->db_state = DB_UNCACHED; 1759 mutex_exit(&dn->dn_dbufs_mtx); 1760 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1761 1762 if (parent && parent != dn->dn_dbuf) 1763 dbuf_add_ref(parent, db); 1764 1765 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1766 refcount_count(&dn->dn_holds) > 0); 1767 (void) refcount_add(&dn->dn_holds, db); 1768 atomic_inc_32(&dn->dn_dbufs_count); 1769 1770 dprintf_dbuf(db, "db=%p\n", db); 1771 1772 return (db); 1773 } 1774 1775 static int 1776 dbuf_do_evict(void *private) 1777 { 1778 dmu_buf_impl_t *db = private; 1779 1780 if (!MUTEX_HELD(&db->db_mtx)) 1781 mutex_enter(&db->db_mtx); 1782 1783 ASSERT(refcount_is_zero(&db->db_holds)); 1784 1785 if (db->db_state != DB_EVICTING) { 1786 ASSERT(db->db_state == DB_CACHED); 1787 DBUF_VERIFY(db); 1788 db->db_buf = NULL; 1789 dbuf_evict(db); 1790 } else { 1791 mutex_exit(&db->db_mtx); 1792 dbuf_destroy(db); 1793 } 1794 return (0); 1795 } 1796 1797 static void 1798 dbuf_destroy(dmu_buf_impl_t *db) 1799 { 1800 ASSERT(refcount_is_zero(&db->db_holds)); 1801 1802 if (db->db_blkid != DMU_BONUS_BLKID) { 1803 /* 1804 * If this dbuf is still on the dn_dbufs list, 1805 * remove it from that list. 1806 */ 1807 if (db->db_dnode_handle != NULL) { 1808 dnode_t *dn; 1809 1810 DB_DNODE_ENTER(db); 1811 dn = DB_DNODE(db); 1812 mutex_enter(&dn->dn_dbufs_mtx); 1813 avl_remove(&dn->dn_dbufs, db); 1814 atomic_dec_32(&dn->dn_dbufs_count); 1815 mutex_exit(&dn->dn_dbufs_mtx); 1816 DB_DNODE_EXIT(db); 1817 /* 1818 * Decrementing the dbuf count means that the hold 1819 * corresponding to the removed dbuf is no longer 1820 * discounted in dnode_move(), so the dnode cannot be 1821 * moved until after we release the hold. 1822 */ 1823 dnode_rele(dn, db); 1824 db->db_dnode_handle = NULL; 1825 } 1826 dbuf_hash_remove(db); 1827 } 1828 db->db_parent = NULL; 1829 db->db_buf = NULL; 1830 1831 ASSERT(db->db.db_data == NULL); 1832 ASSERT(db->db_hash_next == NULL); 1833 ASSERT(db->db_blkptr == NULL); 1834 ASSERT(db->db_data_pending == NULL); 1835 1836 kmem_cache_free(dbuf_cache, db); 1837 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1838 } 1839 1840 void 1841 dbuf_prefetch(dnode_t *dn, uint64_t blkid, zio_priority_t prio) 1842 { 1843 dmu_buf_impl_t *db = NULL; 1844 blkptr_t *bp = NULL; 1845 1846 ASSERT(blkid != DMU_BONUS_BLKID); 1847 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1848 1849 if (dnode_block_freed(dn, blkid)) 1850 return; 1851 1852 /* dbuf_find() returns with db_mtx held */ 1853 if (db = dbuf_find(dn, 0, blkid)) { 1854 /* 1855 * This dbuf is already in the cache. We assume that 1856 * it is already CACHED, or else about to be either 1857 * read or filled. 1858 */ 1859 mutex_exit(&db->db_mtx); 1860 return; 1861 } 1862 1863 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) { 1864 if (bp && !BP_IS_HOLE(bp) && !BP_IS_EMBEDDED(bp)) { 1865 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; 1866 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH; 1867 zbookmark_phys_t zb; 1868 1869 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET, 1870 dn->dn_object, 0, blkid); 1871 1872 (void) arc_read(NULL, dn->dn_objset->os_spa, 1873 bp, NULL, NULL, prio, 1874 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 1875 &aflags, &zb); 1876 } 1877 if (db) 1878 dbuf_rele(db, NULL); 1879 } 1880 } 1881 1882 /* 1883 * Returns with db_holds incremented, and db_mtx not held. 1884 * Note: dn_struct_rwlock must be held. 1885 */ 1886 int 1887 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse, 1888 void *tag, dmu_buf_impl_t **dbp) 1889 { 1890 dmu_buf_impl_t *db, *parent = NULL; 1891 1892 ASSERT(blkid != DMU_BONUS_BLKID); 1893 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1894 ASSERT3U(dn->dn_nlevels, >, level); 1895 1896 *dbp = NULL; 1897 top: 1898 /* dbuf_find() returns with db_mtx held */ 1899 db = dbuf_find(dn, level, blkid); 1900 1901 if (db == NULL) { 1902 blkptr_t *bp = NULL; 1903 int err; 1904 1905 ASSERT3P(parent, ==, NULL); 1906 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp); 1907 if (fail_sparse) { 1908 if (err == 0 && bp && BP_IS_HOLE(bp)) 1909 err = SET_ERROR(ENOENT); 1910 if (err) { 1911 if (parent) 1912 dbuf_rele(parent, NULL); 1913 return (err); 1914 } 1915 } 1916 if (err && err != ENOENT) 1917 return (err); 1918 db = dbuf_create(dn, level, blkid, parent, bp); 1919 } 1920 1921 if (db->db_buf && refcount_is_zero(&db->db_holds)) { 1922 arc_buf_add_ref(db->db_buf, db); 1923 if (db->db_buf->b_data == NULL) { 1924 dbuf_clear(db); 1925 if (parent) { 1926 dbuf_rele(parent, NULL); 1927 parent = NULL; 1928 } 1929 goto top; 1930 } 1931 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data); 1932 } 1933 1934 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf)); 1935 1936 /* 1937 * If this buffer is currently syncing out, and we are are 1938 * still referencing it from db_data, we need to make a copy 1939 * of it in case we decide we want to dirty it again in this txg. 1940 */ 1941 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1942 dn->dn_object != DMU_META_DNODE_OBJECT && 1943 db->db_state == DB_CACHED && db->db_data_pending) { 1944 dbuf_dirty_record_t *dr = db->db_data_pending; 1945 1946 if (dr->dt.dl.dr_data == db->db_buf) { 1947 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 1948 1949 dbuf_set_data(db, 1950 arc_buf_alloc(dn->dn_objset->os_spa, 1951 db->db.db_size, db, type)); 1952 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data, 1953 db->db.db_size); 1954 } 1955 } 1956 1957 (void) refcount_add(&db->db_holds, tag); 1958 DBUF_VERIFY(db); 1959 mutex_exit(&db->db_mtx); 1960 1961 /* NOTE: we can't rele the parent until after we drop the db_mtx */ 1962 if (parent) 1963 dbuf_rele(parent, NULL); 1964 1965 ASSERT3P(DB_DNODE(db), ==, dn); 1966 ASSERT3U(db->db_blkid, ==, blkid); 1967 ASSERT3U(db->db_level, ==, level); 1968 *dbp = db; 1969 1970 return (0); 1971 } 1972 1973 dmu_buf_impl_t * 1974 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag) 1975 { 1976 dmu_buf_impl_t *db; 1977 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db); 1978 return (err ? NULL : db); 1979 } 1980 1981 dmu_buf_impl_t * 1982 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag) 1983 { 1984 dmu_buf_impl_t *db; 1985 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db); 1986 return (err ? NULL : db); 1987 } 1988 1989 void 1990 dbuf_create_bonus(dnode_t *dn) 1991 { 1992 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 1993 1994 ASSERT(dn->dn_bonus == NULL); 1995 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL); 1996 } 1997 1998 int 1999 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx) 2000 { 2001 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2002 dnode_t *dn; 2003 2004 if (db->db_blkid != DMU_SPILL_BLKID) 2005 return (SET_ERROR(ENOTSUP)); 2006 if (blksz == 0) 2007 blksz = SPA_MINBLOCKSIZE; 2008 ASSERT3U(blksz, <=, spa_maxblocksize(dmu_objset_spa(db->db_objset))); 2009 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE); 2010 2011 DB_DNODE_ENTER(db); 2012 dn = DB_DNODE(db); 2013 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 2014 dbuf_new_size(db, blksz, tx); 2015 rw_exit(&dn->dn_struct_rwlock); 2016 DB_DNODE_EXIT(db); 2017 2018 return (0); 2019 } 2020 2021 void 2022 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx) 2023 { 2024 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx); 2025 } 2026 2027 #pragma weak dmu_buf_add_ref = dbuf_add_ref 2028 void 2029 dbuf_add_ref(dmu_buf_impl_t *db, void *tag) 2030 { 2031 int64_t holds = refcount_add(&db->db_holds, tag); 2032 ASSERT(holds > 1); 2033 } 2034 2035 /* 2036 * If you call dbuf_rele() you had better not be referencing the dnode handle 2037 * unless you have some other direct or indirect hold on the dnode. (An indirect 2038 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.) 2039 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the 2040 * dnode's parent dbuf evicting its dnode handles. 2041 */ 2042 void 2043 dbuf_rele(dmu_buf_impl_t *db, void *tag) 2044 { 2045 mutex_enter(&db->db_mtx); 2046 dbuf_rele_and_unlock(db, tag); 2047 } 2048 2049 void 2050 dmu_buf_rele(dmu_buf_t *db, void *tag) 2051 { 2052 dbuf_rele((dmu_buf_impl_t *)db, tag); 2053 } 2054 2055 /* 2056 * dbuf_rele() for an already-locked dbuf. This is necessary to allow 2057 * db_dirtycnt and db_holds to be updated atomically. 2058 */ 2059 void 2060 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) 2061 { 2062 int64_t holds; 2063 2064 ASSERT(MUTEX_HELD(&db->db_mtx)); 2065 DBUF_VERIFY(db); 2066 2067 /* 2068 * Remove the reference to the dbuf before removing its hold on the 2069 * dnode so we can guarantee in dnode_move() that a referenced bonus 2070 * buffer has a corresponding dnode hold. 2071 */ 2072 holds = refcount_remove(&db->db_holds, tag); 2073 ASSERT(holds >= 0); 2074 2075 /* 2076 * We can't freeze indirects if there is a possibility that they 2077 * may be modified in the current syncing context. 2078 */ 2079 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0)) 2080 arc_buf_freeze(db->db_buf); 2081 2082 if (holds == db->db_dirtycnt && 2083 db->db_level == 0 && db->db_immediate_evict) 2084 dbuf_evict_user(db); 2085 2086 if (holds == 0) { 2087 if (db->db_blkid == DMU_BONUS_BLKID) { 2088 mutex_exit(&db->db_mtx); 2089 2090 /* 2091 * If the dnode moves here, we cannot cross this barrier 2092 * until the move completes. 2093 */ 2094 DB_DNODE_ENTER(db); 2095 atomic_dec_32(&DB_DNODE(db)->dn_dbufs_count); 2096 DB_DNODE_EXIT(db); 2097 /* 2098 * The bonus buffer's dnode hold is no longer discounted 2099 * in dnode_move(). The dnode cannot move until after 2100 * the dnode_rele(). 2101 */ 2102 dnode_rele(DB_DNODE(db), db); 2103 } else if (db->db_buf == NULL) { 2104 /* 2105 * This is a special case: we never associated this 2106 * dbuf with any data allocated from the ARC. 2107 */ 2108 ASSERT(db->db_state == DB_UNCACHED || 2109 db->db_state == DB_NOFILL); 2110 dbuf_evict(db); 2111 } else if (arc_released(db->db_buf)) { 2112 arc_buf_t *buf = db->db_buf; 2113 /* 2114 * This dbuf has anonymous data associated with it. 2115 */ 2116 dbuf_set_data(db, NULL); 2117 VERIFY(arc_buf_remove_ref(buf, db)); 2118 dbuf_evict(db); 2119 } else { 2120 VERIFY(!arc_buf_remove_ref(db->db_buf, db)); 2121 2122 /* 2123 * A dbuf will be eligible for eviction if either the 2124 * 'primarycache' property is set or a duplicate 2125 * copy of this buffer is already cached in the arc. 2126 * 2127 * In the case of the 'primarycache' a buffer 2128 * is considered for eviction if it matches the 2129 * criteria set in the property. 2130 * 2131 * To decide if our buffer is considered a 2132 * duplicate, we must call into the arc to determine 2133 * if multiple buffers are referencing the same 2134 * block on-disk. If so, then we simply evict 2135 * ourselves. 2136 */ 2137 if (!DBUF_IS_CACHEABLE(db)) { 2138 if (db->db_blkptr != NULL && 2139 !BP_IS_HOLE(db->db_blkptr) && 2140 !BP_IS_EMBEDDED(db->db_blkptr)) { 2141 spa_t *spa = 2142 dmu_objset_spa(db->db_objset); 2143 blkptr_t bp = *db->db_blkptr; 2144 dbuf_clear(db); 2145 arc_freed(spa, &bp); 2146 } else { 2147 dbuf_clear(db); 2148 } 2149 } else if (arc_buf_eviction_needed(db->db_buf)) { 2150 dbuf_clear(db); 2151 } else { 2152 mutex_exit(&db->db_mtx); 2153 } 2154 } 2155 } else { 2156 mutex_exit(&db->db_mtx); 2157 } 2158 } 2159 2160 #pragma weak dmu_buf_refcount = dbuf_refcount 2161 uint64_t 2162 dbuf_refcount(dmu_buf_impl_t *db) 2163 { 2164 return (refcount_count(&db->db_holds)); 2165 } 2166 2167 void * 2168 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, 2169 dmu_buf_evict_func_t *evict_func) 2170 { 2171 return (dmu_buf_update_user(db_fake, NULL, user_ptr, evict_func)); 2172 } 2173 2174 void * 2175 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, 2176 dmu_buf_evict_func_t *evict_func) 2177 { 2178 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2179 2180 db->db_immediate_evict = TRUE; 2181 return (dmu_buf_update_user(db_fake, NULL, user_ptr, evict_func)); 2182 } 2183 2184 void * 2185 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr, 2186 dmu_buf_evict_func_t *evict_func) 2187 { 2188 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2189 ASSERT(db->db_level == 0); 2190 2191 ASSERT((user_ptr == NULL) == (evict_func == NULL)); 2192 2193 mutex_enter(&db->db_mtx); 2194 2195 if (db->db_user_ptr == old_user_ptr) { 2196 db->db_user_ptr = user_ptr; 2197 db->db_evict_func = evict_func; 2198 } else { 2199 old_user_ptr = db->db_user_ptr; 2200 } 2201 2202 mutex_exit(&db->db_mtx); 2203 return (old_user_ptr); 2204 } 2205 2206 void * 2207 dmu_buf_get_user(dmu_buf_t *db_fake) 2208 { 2209 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2210 ASSERT(!refcount_is_zero(&db->db_holds)); 2211 2212 return (db->db_user_ptr); 2213 } 2214 2215 boolean_t 2216 dmu_buf_freeable(dmu_buf_t *dbuf) 2217 { 2218 boolean_t res = B_FALSE; 2219 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 2220 2221 if (db->db_blkptr) 2222 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset, 2223 db->db_blkptr, db->db_blkptr->blk_birth); 2224 2225 return (res); 2226 } 2227 2228 blkptr_t * 2229 dmu_buf_get_blkptr(dmu_buf_t *db) 2230 { 2231 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; 2232 return (dbi->db_blkptr); 2233 } 2234 2235 static void 2236 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db) 2237 { 2238 /* ASSERT(dmu_tx_is_syncing(tx) */ 2239 ASSERT(MUTEX_HELD(&db->db_mtx)); 2240 2241 if (db->db_blkptr != NULL) 2242 return; 2243 2244 if (db->db_blkid == DMU_SPILL_BLKID) { 2245 db->db_blkptr = &dn->dn_phys->dn_spill; 2246 BP_ZERO(db->db_blkptr); 2247 return; 2248 } 2249 if (db->db_level == dn->dn_phys->dn_nlevels-1) { 2250 /* 2251 * This buffer was allocated at a time when there was 2252 * no available blkptrs from the dnode, or it was 2253 * inappropriate to hook it in (i.e., nlevels mis-match). 2254 */ 2255 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr); 2256 ASSERT(db->db_parent == NULL); 2257 db->db_parent = dn->dn_dbuf; 2258 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid]; 2259 DBUF_VERIFY(db); 2260 } else { 2261 dmu_buf_impl_t *parent = db->db_parent; 2262 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2263 2264 ASSERT(dn->dn_phys->dn_nlevels > 1); 2265 if (parent == NULL) { 2266 mutex_exit(&db->db_mtx); 2267 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2268 (void) dbuf_hold_impl(dn, db->db_level+1, 2269 db->db_blkid >> epbs, FALSE, db, &parent); 2270 rw_exit(&dn->dn_struct_rwlock); 2271 mutex_enter(&db->db_mtx); 2272 db->db_parent = parent; 2273 } 2274 db->db_blkptr = (blkptr_t *)parent->db.db_data + 2275 (db->db_blkid & ((1ULL << epbs) - 1)); 2276 DBUF_VERIFY(db); 2277 } 2278 } 2279 2280 static void 2281 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2282 { 2283 dmu_buf_impl_t *db = dr->dr_dbuf; 2284 dnode_t *dn; 2285 zio_t *zio; 2286 2287 ASSERT(dmu_tx_is_syncing(tx)); 2288 2289 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2290 2291 mutex_enter(&db->db_mtx); 2292 2293 ASSERT(db->db_level > 0); 2294 DBUF_VERIFY(db); 2295 2296 /* Read the block if it hasn't been read yet. */ 2297 if (db->db_buf == NULL) { 2298 mutex_exit(&db->db_mtx); 2299 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); 2300 mutex_enter(&db->db_mtx); 2301 } 2302 ASSERT3U(db->db_state, ==, DB_CACHED); 2303 ASSERT(db->db_buf != NULL); 2304 2305 DB_DNODE_ENTER(db); 2306 dn = DB_DNODE(db); 2307 /* Indirect block size must match what the dnode thinks it is. */ 2308 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2309 dbuf_check_blkptr(dn, db); 2310 DB_DNODE_EXIT(db); 2311 2312 /* Provide the pending dirty record to child dbufs */ 2313 db->db_data_pending = dr; 2314 2315 mutex_exit(&db->db_mtx); 2316 dbuf_write(dr, db->db_buf, tx); 2317 2318 zio = dr->dr_zio; 2319 mutex_enter(&dr->dt.di.dr_mtx); 2320 dbuf_sync_list(&dr->dt.di.dr_children, tx); 2321 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2322 mutex_exit(&dr->dt.di.dr_mtx); 2323 zio_nowait(zio); 2324 } 2325 2326 static void 2327 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2328 { 2329 arc_buf_t **datap = &dr->dt.dl.dr_data; 2330 dmu_buf_impl_t *db = dr->dr_dbuf; 2331 dnode_t *dn; 2332 objset_t *os; 2333 uint64_t txg = tx->tx_txg; 2334 2335 ASSERT(dmu_tx_is_syncing(tx)); 2336 2337 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2338 2339 mutex_enter(&db->db_mtx); 2340 /* 2341 * To be synced, we must be dirtied. But we 2342 * might have been freed after the dirty. 2343 */ 2344 if (db->db_state == DB_UNCACHED) { 2345 /* This buffer has been freed since it was dirtied */ 2346 ASSERT(db->db.db_data == NULL); 2347 } else if (db->db_state == DB_FILL) { 2348 /* This buffer was freed and is now being re-filled */ 2349 ASSERT(db->db.db_data != dr->dt.dl.dr_data); 2350 } else { 2351 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); 2352 } 2353 DBUF_VERIFY(db); 2354 2355 DB_DNODE_ENTER(db); 2356 dn = DB_DNODE(db); 2357 2358 if (db->db_blkid == DMU_SPILL_BLKID) { 2359 mutex_enter(&dn->dn_mtx); 2360 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR; 2361 mutex_exit(&dn->dn_mtx); 2362 } 2363 2364 /* 2365 * If this is a bonus buffer, simply copy the bonus data into the 2366 * dnode. It will be written out when the dnode is synced (and it 2367 * will be synced, since it must have been dirty for dbuf_sync to 2368 * be called). 2369 */ 2370 if (db->db_blkid == DMU_BONUS_BLKID) { 2371 dbuf_dirty_record_t **drp; 2372 2373 ASSERT(*datap != NULL); 2374 ASSERT0(db->db_level); 2375 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN); 2376 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen); 2377 DB_DNODE_EXIT(db); 2378 2379 if (*datap != db->db.db_data) { 2380 zio_buf_free(*datap, DN_MAX_BONUSLEN); 2381 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 2382 } 2383 db->db_data_pending = NULL; 2384 drp = &db->db_last_dirty; 2385 while (*drp != dr) 2386 drp = &(*drp)->dr_next; 2387 ASSERT(dr->dr_next == NULL); 2388 ASSERT(dr->dr_dbuf == db); 2389 *drp = dr->dr_next; 2390 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2391 ASSERT(db->db_dirtycnt > 0); 2392 db->db_dirtycnt -= 1; 2393 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2394 return; 2395 } 2396 2397 os = dn->dn_objset; 2398 2399 /* 2400 * This function may have dropped the db_mtx lock allowing a dmu_sync 2401 * operation to sneak in. As a result, we need to ensure that we 2402 * don't check the dr_override_state until we have returned from 2403 * dbuf_check_blkptr. 2404 */ 2405 dbuf_check_blkptr(dn, db); 2406 2407 /* 2408 * If this buffer is in the middle of an immediate write, 2409 * wait for the synchronous IO to complete. 2410 */ 2411 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) { 2412 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); 2413 cv_wait(&db->db_changed, &db->db_mtx); 2414 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN); 2415 } 2416 2417 if (db->db_state != DB_NOFILL && 2418 dn->dn_object != DMU_META_DNODE_OBJECT && 2419 refcount_count(&db->db_holds) > 1 && 2420 dr->dt.dl.dr_override_state != DR_OVERRIDDEN && 2421 *datap == db->db_buf) { 2422 /* 2423 * If this buffer is currently "in use" (i.e., there 2424 * are active holds and db_data still references it), 2425 * then make a copy before we start the write so that 2426 * any modifications from the open txg will not leak 2427 * into this write. 2428 * 2429 * NOTE: this copy does not need to be made for 2430 * objects only modified in the syncing context (e.g. 2431 * DNONE_DNODE blocks). 2432 */ 2433 int blksz = arc_buf_size(*datap); 2434 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2435 *datap = arc_buf_alloc(os->os_spa, blksz, db, type); 2436 bcopy(db->db.db_data, (*datap)->b_data, blksz); 2437 } 2438 db->db_data_pending = dr; 2439 2440 mutex_exit(&db->db_mtx); 2441 2442 dbuf_write(dr, *datap, tx); 2443 2444 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2445 if (dn->dn_object == DMU_META_DNODE_OBJECT) { 2446 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr); 2447 DB_DNODE_EXIT(db); 2448 } else { 2449 /* 2450 * Although zio_nowait() does not "wait for an IO", it does 2451 * initiate the IO. If this is an empty write it seems plausible 2452 * that the IO could actually be completed before the nowait 2453 * returns. We need to DB_DNODE_EXIT() first in case 2454 * zio_nowait() invalidates the dbuf. 2455 */ 2456 DB_DNODE_EXIT(db); 2457 zio_nowait(dr->dr_zio); 2458 } 2459 } 2460 2461 void 2462 dbuf_sync_list(list_t *list, dmu_tx_t *tx) 2463 { 2464 dbuf_dirty_record_t *dr; 2465 2466 while (dr = list_head(list)) { 2467 if (dr->dr_zio != NULL) { 2468 /* 2469 * If we find an already initialized zio then we 2470 * are processing the meta-dnode, and we have finished. 2471 * The dbufs for all dnodes are put back on the list 2472 * during processing, so that we can zio_wait() 2473 * these IOs after initiating all child IOs. 2474 */ 2475 ASSERT3U(dr->dr_dbuf->db.db_object, ==, 2476 DMU_META_DNODE_OBJECT); 2477 break; 2478 } 2479 list_remove(list, dr); 2480 if (dr->dr_dbuf->db_level > 0) 2481 dbuf_sync_indirect(dr, tx); 2482 else 2483 dbuf_sync_leaf(dr, tx); 2484 } 2485 } 2486 2487 /* ARGSUSED */ 2488 static void 2489 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb) 2490 { 2491 dmu_buf_impl_t *db = vdb; 2492 dnode_t *dn; 2493 blkptr_t *bp = zio->io_bp; 2494 blkptr_t *bp_orig = &zio->io_bp_orig; 2495 spa_t *spa = zio->io_spa; 2496 int64_t delta; 2497 uint64_t fill = 0; 2498 int i; 2499 2500 ASSERT3P(db->db_blkptr, ==, bp); 2501 2502 DB_DNODE_ENTER(db); 2503 dn = DB_DNODE(db); 2504 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig); 2505 dnode_diduse_space(dn, delta - zio->io_prev_space_delta); 2506 zio->io_prev_space_delta = delta; 2507 2508 if (bp->blk_birth != 0) { 2509 ASSERT((db->db_blkid != DMU_SPILL_BLKID && 2510 BP_GET_TYPE(bp) == dn->dn_type) || 2511 (db->db_blkid == DMU_SPILL_BLKID && 2512 BP_GET_TYPE(bp) == dn->dn_bonustype) || 2513 BP_IS_EMBEDDED(bp)); 2514 ASSERT(BP_GET_LEVEL(bp) == db->db_level); 2515 } 2516 2517 mutex_enter(&db->db_mtx); 2518 2519 #ifdef ZFS_DEBUG 2520 if (db->db_blkid == DMU_SPILL_BLKID) { 2521 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2522 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2523 db->db_blkptr == &dn->dn_phys->dn_spill); 2524 } 2525 #endif 2526 2527 if (db->db_level == 0) { 2528 mutex_enter(&dn->dn_mtx); 2529 if (db->db_blkid > dn->dn_phys->dn_maxblkid && 2530 db->db_blkid != DMU_SPILL_BLKID) 2531 dn->dn_phys->dn_maxblkid = db->db_blkid; 2532 mutex_exit(&dn->dn_mtx); 2533 2534 if (dn->dn_type == DMU_OT_DNODE) { 2535 dnode_phys_t *dnp = db->db.db_data; 2536 for (i = db->db.db_size >> DNODE_SHIFT; i > 0; 2537 i--, dnp++) { 2538 if (dnp->dn_type != DMU_OT_NONE) 2539 fill++; 2540 } 2541 } else { 2542 if (BP_IS_HOLE(bp)) { 2543 fill = 0; 2544 } else { 2545 fill = 1; 2546 } 2547 } 2548 } else { 2549 blkptr_t *ibp = db->db.db_data; 2550 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2551 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) { 2552 if (BP_IS_HOLE(ibp)) 2553 continue; 2554 fill += BP_GET_FILL(ibp); 2555 } 2556 } 2557 DB_DNODE_EXIT(db); 2558 2559 if (!BP_IS_EMBEDDED(bp)) 2560 bp->blk_fill = fill; 2561 2562 mutex_exit(&db->db_mtx); 2563 } 2564 2565 /* 2566 * The SPA will call this callback several times for each zio - once 2567 * for every physical child i/o (zio->io_phys_children times). This 2568 * allows the DMU to monitor the progress of each logical i/o. For example, 2569 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z 2570 * block. There may be a long delay before all copies/fragments are completed, 2571 * so this callback allows us to retire dirty space gradually, as the physical 2572 * i/os complete. 2573 */ 2574 /* ARGSUSED */ 2575 static void 2576 dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg) 2577 { 2578 dmu_buf_impl_t *db = arg; 2579 objset_t *os = db->db_objset; 2580 dsl_pool_t *dp = dmu_objset_pool(os); 2581 dbuf_dirty_record_t *dr; 2582 int delta = 0; 2583 2584 dr = db->db_data_pending; 2585 ASSERT3U(dr->dr_txg, ==, zio->io_txg); 2586 2587 /* 2588 * The callback will be called io_phys_children times. Retire one 2589 * portion of our dirty space each time we are called. Any rounding 2590 * error will be cleaned up by dsl_pool_sync()'s call to 2591 * dsl_pool_undirty_space(). 2592 */ 2593 delta = dr->dr_accounted / zio->io_phys_children; 2594 dsl_pool_undirty_space(dp, delta, zio->io_txg); 2595 } 2596 2597 /* ARGSUSED */ 2598 static void 2599 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb) 2600 { 2601 dmu_buf_impl_t *db = vdb; 2602 blkptr_t *bp_orig = &zio->io_bp_orig; 2603 blkptr_t *bp = db->db_blkptr; 2604 objset_t *os = db->db_objset; 2605 dmu_tx_t *tx = os->os_synctx; 2606 dbuf_dirty_record_t **drp, *dr; 2607 2608 ASSERT0(zio->io_error); 2609 ASSERT(db->db_blkptr == bp); 2610 2611 /* 2612 * For nopwrites and rewrites we ensure that the bp matches our 2613 * original and bypass all the accounting. 2614 */ 2615 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) { 2616 ASSERT(BP_EQUAL(bp, bp_orig)); 2617 } else { 2618 dsl_dataset_t *ds = os->os_dsl_dataset; 2619 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE); 2620 dsl_dataset_block_born(ds, bp, tx); 2621 } 2622 2623 mutex_enter(&db->db_mtx); 2624 2625 DBUF_VERIFY(db); 2626 2627 drp = &db->db_last_dirty; 2628 while ((dr = *drp) != db->db_data_pending) 2629 drp = &dr->dr_next; 2630 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2631 ASSERT(dr->dr_dbuf == db); 2632 ASSERT(dr->dr_next == NULL); 2633 *drp = dr->dr_next; 2634 2635 #ifdef ZFS_DEBUG 2636 if (db->db_blkid == DMU_SPILL_BLKID) { 2637 dnode_t *dn; 2638 2639 DB_DNODE_ENTER(db); 2640 dn = DB_DNODE(db); 2641 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2642 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2643 db->db_blkptr == &dn->dn_phys->dn_spill); 2644 DB_DNODE_EXIT(db); 2645 } 2646 #endif 2647 2648 if (db->db_level == 0) { 2649 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 2650 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN); 2651 if (db->db_state != DB_NOFILL) { 2652 if (dr->dt.dl.dr_data != db->db_buf) 2653 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 2654 db)); 2655 else if (!arc_released(db->db_buf)) 2656 arc_set_callback(db->db_buf, dbuf_do_evict, db); 2657 } 2658 } else { 2659 dnode_t *dn; 2660 2661 DB_DNODE_ENTER(db); 2662 dn = DB_DNODE(db); 2663 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2664 ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift); 2665 if (!BP_IS_HOLE(db->db_blkptr)) { 2666 int epbs = 2667 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2668 ASSERT3U(db->db_blkid, <=, 2669 dn->dn_phys->dn_maxblkid >> (db->db_level * epbs)); 2670 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, 2671 db->db.db_size); 2672 if (!arc_released(db->db_buf)) 2673 arc_set_callback(db->db_buf, dbuf_do_evict, db); 2674 } 2675 DB_DNODE_EXIT(db); 2676 mutex_destroy(&dr->dt.di.dr_mtx); 2677 list_destroy(&dr->dt.di.dr_children); 2678 } 2679 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2680 2681 cv_broadcast(&db->db_changed); 2682 ASSERT(db->db_dirtycnt > 0); 2683 db->db_dirtycnt -= 1; 2684 db->db_data_pending = NULL; 2685 dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg); 2686 } 2687 2688 static void 2689 dbuf_write_nofill_ready(zio_t *zio) 2690 { 2691 dbuf_write_ready(zio, NULL, zio->io_private); 2692 } 2693 2694 static void 2695 dbuf_write_nofill_done(zio_t *zio) 2696 { 2697 dbuf_write_done(zio, NULL, zio->io_private); 2698 } 2699 2700 static void 2701 dbuf_write_override_ready(zio_t *zio) 2702 { 2703 dbuf_dirty_record_t *dr = zio->io_private; 2704 dmu_buf_impl_t *db = dr->dr_dbuf; 2705 2706 dbuf_write_ready(zio, NULL, db); 2707 } 2708 2709 static void 2710 dbuf_write_override_done(zio_t *zio) 2711 { 2712 dbuf_dirty_record_t *dr = zio->io_private; 2713 dmu_buf_impl_t *db = dr->dr_dbuf; 2714 blkptr_t *obp = &dr->dt.dl.dr_overridden_by; 2715 2716 mutex_enter(&db->db_mtx); 2717 if (!BP_EQUAL(zio->io_bp, obp)) { 2718 if (!BP_IS_HOLE(obp)) 2719 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp); 2720 arc_release(dr->dt.dl.dr_data, db); 2721 } 2722 mutex_exit(&db->db_mtx); 2723 2724 dbuf_write_done(zio, NULL, db); 2725 } 2726 2727 /* Issue I/O to commit a dirty buffer to disk. */ 2728 static void 2729 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) 2730 { 2731 dmu_buf_impl_t *db = dr->dr_dbuf; 2732 dnode_t *dn; 2733 objset_t *os; 2734 dmu_buf_impl_t *parent = db->db_parent; 2735 uint64_t txg = tx->tx_txg; 2736 zbookmark_phys_t zb; 2737 zio_prop_t zp; 2738 zio_t *zio; 2739 int wp_flag = 0; 2740 2741 DB_DNODE_ENTER(db); 2742 dn = DB_DNODE(db); 2743 os = dn->dn_objset; 2744 2745 if (db->db_state != DB_NOFILL) { 2746 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) { 2747 /* 2748 * Private object buffers are released here rather 2749 * than in dbuf_dirty() since they are only modified 2750 * in the syncing context and we don't want the 2751 * overhead of making multiple copies of the data. 2752 */ 2753 if (BP_IS_HOLE(db->db_blkptr)) { 2754 arc_buf_thaw(data); 2755 } else { 2756 dbuf_release_bp(db); 2757 } 2758 } 2759 } 2760 2761 if (parent != dn->dn_dbuf) { 2762 /* Our parent is an indirect block. */ 2763 /* We have a dirty parent that has been scheduled for write. */ 2764 ASSERT(parent && parent->db_data_pending); 2765 /* Our parent's buffer is one level closer to the dnode. */ 2766 ASSERT(db->db_level == parent->db_level-1); 2767 /* 2768 * We're about to modify our parent's db_data by modifying 2769 * our block pointer, so the parent must be released. 2770 */ 2771 ASSERT(arc_released(parent->db_buf)); 2772 zio = parent->db_data_pending->dr_zio; 2773 } else { 2774 /* Our parent is the dnode itself. */ 2775 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && 2776 db->db_blkid != DMU_SPILL_BLKID) || 2777 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); 2778 if (db->db_blkid != DMU_SPILL_BLKID) 2779 ASSERT3P(db->db_blkptr, ==, 2780 &dn->dn_phys->dn_blkptr[db->db_blkid]); 2781 zio = dn->dn_zio; 2782 } 2783 2784 ASSERT(db->db_level == 0 || data == db->db_buf); 2785 ASSERT3U(db->db_blkptr->blk_birth, <=, txg); 2786 ASSERT(zio); 2787 2788 SET_BOOKMARK(&zb, os->os_dsl_dataset ? 2789 os->os_dsl_dataset->ds_object : DMU_META_OBJSET, 2790 db->db.db_object, db->db_level, db->db_blkid); 2791 2792 if (db->db_blkid == DMU_SPILL_BLKID) 2793 wp_flag = WP_SPILL; 2794 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0; 2795 2796 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp); 2797 DB_DNODE_EXIT(db); 2798 2799 if (db->db_level == 0 && 2800 dr->dt.dl.dr_override_state == DR_OVERRIDDEN) { 2801 /* 2802 * The BP for this block has been provided by open context 2803 * (by dmu_sync() or dmu_buf_write_embedded()). 2804 */ 2805 void *contents = (data != NULL) ? data->b_data : NULL; 2806 2807 dr->dr_zio = zio_write(zio, os->os_spa, txg, 2808 db->db_blkptr, contents, db->db.db_size, &zp, 2809 dbuf_write_override_ready, NULL, dbuf_write_override_done, 2810 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 2811 mutex_enter(&db->db_mtx); 2812 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 2813 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by, 2814 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite); 2815 mutex_exit(&db->db_mtx); 2816 } else if (db->db_state == DB_NOFILL) { 2817 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF || 2818 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY); 2819 dr->dr_zio = zio_write(zio, os->os_spa, txg, 2820 db->db_blkptr, NULL, db->db.db_size, &zp, 2821 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db, 2822 ZIO_PRIORITY_ASYNC_WRITE, 2823 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb); 2824 } else { 2825 ASSERT(arc_released(data)); 2826 dr->dr_zio = arc_write(zio, os->os_spa, txg, 2827 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), 2828 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready, 2829 dbuf_write_physdone, dbuf_write_done, db, 2830 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 2831 } 2832 } 2833