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) 2013 by Delphix. All rights reserved. 25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved. 26 */ 27 28 #include <sys/zfs_context.h> 29 #include <sys/dmu.h> 30 #include <sys/dmu_send.h> 31 #include <sys/dmu_impl.h> 32 #include <sys/dbuf.h> 33 #include <sys/dmu_objset.h> 34 #include <sys/dsl_dataset.h> 35 #include <sys/dsl_dir.h> 36 #include <sys/dmu_tx.h> 37 #include <sys/spa.h> 38 #include <sys/zio.h> 39 #include <sys/dmu_zfetch.h> 40 #include <sys/sa.h> 41 #include <sys/sa_impl.h> 42 43 static void dbuf_destroy(dmu_buf_impl_t *db); 44 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 45 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx); 46 47 /* 48 * Global data structures and functions for the dbuf cache. 49 */ 50 static kmem_cache_t *dbuf_cache; 51 52 /* ARGSUSED */ 53 static int 54 dbuf_cons(void *vdb, void *unused, int kmflag) 55 { 56 dmu_buf_impl_t *db = vdb; 57 bzero(db, sizeof (dmu_buf_impl_t)); 58 59 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL); 60 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL); 61 refcount_create(&db->db_holds); 62 return (0); 63 } 64 65 /* ARGSUSED */ 66 static void 67 dbuf_dest(void *vdb, void *unused) 68 { 69 dmu_buf_impl_t *db = vdb; 70 mutex_destroy(&db->db_mtx); 71 cv_destroy(&db->db_changed); 72 refcount_destroy(&db->db_holds); 73 } 74 75 /* 76 * dbuf hash table routines 77 */ 78 static dbuf_hash_table_t dbuf_hash_table; 79 80 static uint64_t dbuf_hash_count; 81 82 static uint64_t 83 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid) 84 { 85 uintptr_t osv = (uintptr_t)os; 86 uint64_t crc = -1ULL; 87 88 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); 89 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF]; 90 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF]; 91 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF]; 92 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF]; 93 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF]; 94 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF]; 95 96 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16); 97 98 return (crc); 99 } 100 101 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid); 102 103 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \ 104 ((dbuf)->db.db_object == (obj) && \ 105 (dbuf)->db_objset == (os) && \ 106 (dbuf)->db_level == (level) && \ 107 (dbuf)->db_blkid == (blkid)) 108 109 dmu_buf_impl_t * 110 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid) 111 { 112 dbuf_hash_table_t *h = &dbuf_hash_table; 113 objset_t *os = dn->dn_objset; 114 uint64_t obj = dn->dn_object; 115 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 116 uint64_t idx = hv & h->hash_table_mask; 117 dmu_buf_impl_t *db; 118 119 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 120 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) { 121 if (DBUF_EQUAL(db, os, obj, level, blkid)) { 122 mutex_enter(&db->db_mtx); 123 if (db->db_state != DB_EVICTING) { 124 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 125 return (db); 126 } 127 mutex_exit(&db->db_mtx); 128 } 129 } 130 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 131 return (NULL); 132 } 133 134 /* 135 * Insert an entry into the hash table. If there is already an element 136 * equal to elem in the hash table, then the already existing element 137 * will be returned and the new element will not be inserted. 138 * Otherwise returns NULL. 139 */ 140 static dmu_buf_impl_t * 141 dbuf_hash_insert(dmu_buf_impl_t *db) 142 { 143 dbuf_hash_table_t *h = &dbuf_hash_table; 144 objset_t *os = db->db_objset; 145 uint64_t obj = db->db.db_object; 146 int level = db->db_level; 147 uint64_t blkid = db->db_blkid; 148 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 149 uint64_t idx = hv & h->hash_table_mask; 150 dmu_buf_impl_t *dbf; 151 152 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 153 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) { 154 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) { 155 mutex_enter(&dbf->db_mtx); 156 if (dbf->db_state != DB_EVICTING) { 157 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 158 return (dbf); 159 } 160 mutex_exit(&dbf->db_mtx); 161 } 162 } 163 164 mutex_enter(&db->db_mtx); 165 db->db_hash_next = h->hash_table[idx]; 166 h->hash_table[idx] = db; 167 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 168 atomic_add_64(&dbuf_hash_count, 1); 169 170 return (NULL); 171 } 172 173 /* 174 * Remove an entry from the hash table. This operation will 175 * fail if there are any existing holds on the db. 176 */ 177 static void 178 dbuf_hash_remove(dmu_buf_impl_t *db) 179 { 180 dbuf_hash_table_t *h = &dbuf_hash_table; 181 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object, 182 db->db_level, db->db_blkid); 183 uint64_t idx = hv & h->hash_table_mask; 184 dmu_buf_impl_t *dbf, **dbp; 185 186 /* 187 * We musn't hold db_mtx to maintin lock ordering: 188 * DBUF_HASH_MUTEX > db_mtx. 189 */ 190 ASSERT(refcount_is_zero(&db->db_holds)); 191 ASSERT(db->db_state == DB_EVICTING); 192 ASSERT(!MUTEX_HELD(&db->db_mtx)); 193 194 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 195 dbp = &h->hash_table[idx]; 196 while ((dbf = *dbp) != db) { 197 dbp = &dbf->db_hash_next; 198 ASSERT(dbf != NULL); 199 } 200 *dbp = db->db_hash_next; 201 db->db_hash_next = NULL; 202 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 203 atomic_add_64(&dbuf_hash_count, -1); 204 } 205 206 static arc_evict_func_t dbuf_do_evict; 207 208 static void 209 dbuf_evict_user(dmu_buf_impl_t *db) 210 { 211 ASSERT(MUTEX_HELD(&db->db_mtx)); 212 213 if (db->db_level != 0 || db->db_evict_func == NULL) 214 return; 215 216 if (db->db_user_data_ptr_ptr) 217 *db->db_user_data_ptr_ptr = db->db.db_data; 218 db->db_evict_func(&db->db, db->db_user_ptr); 219 db->db_user_ptr = NULL; 220 db->db_user_data_ptr_ptr = NULL; 221 db->db_evict_func = NULL; 222 } 223 224 boolean_t 225 dbuf_is_metadata(dmu_buf_impl_t *db) 226 { 227 if (db->db_level > 0) { 228 return (B_TRUE); 229 } else { 230 boolean_t is_metadata; 231 232 DB_DNODE_ENTER(db); 233 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type); 234 DB_DNODE_EXIT(db); 235 236 return (is_metadata); 237 } 238 } 239 240 void 241 dbuf_evict(dmu_buf_impl_t *db) 242 { 243 ASSERT(MUTEX_HELD(&db->db_mtx)); 244 ASSERT(db->db_buf == NULL); 245 ASSERT(db->db_data_pending == NULL); 246 247 dbuf_clear(db); 248 dbuf_destroy(db); 249 } 250 251 void 252 dbuf_init(void) 253 { 254 uint64_t hsize = 1ULL << 16; 255 dbuf_hash_table_t *h = &dbuf_hash_table; 256 int i; 257 258 /* 259 * The hash table is big enough to fill all of physical memory 260 * with an average 4K block size. The table will take up 261 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers). 262 */ 263 while (hsize * 4096 < physmem * PAGESIZE) 264 hsize <<= 1; 265 266 retry: 267 h->hash_table_mask = hsize - 1; 268 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP); 269 if (h->hash_table == NULL) { 270 /* XXX - we should really return an error instead of assert */ 271 ASSERT(hsize > (1ULL << 10)); 272 hsize >>= 1; 273 goto retry; 274 } 275 276 dbuf_cache = kmem_cache_create("dmu_buf_impl_t", 277 sizeof (dmu_buf_impl_t), 278 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0); 279 280 for (i = 0; i < DBUF_MUTEXES; i++) 281 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL); 282 } 283 284 void 285 dbuf_fini(void) 286 { 287 dbuf_hash_table_t *h = &dbuf_hash_table; 288 int i; 289 290 for (i = 0; i < DBUF_MUTEXES; i++) 291 mutex_destroy(&h->hash_mutexes[i]); 292 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *)); 293 kmem_cache_destroy(dbuf_cache); 294 } 295 296 /* 297 * Other stuff. 298 */ 299 300 #ifdef ZFS_DEBUG 301 static void 302 dbuf_verify(dmu_buf_impl_t *db) 303 { 304 dnode_t *dn; 305 dbuf_dirty_record_t *dr; 306 307 ASSERT(MUTEX_HELD(&db->db_mtx)); 308 309 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY)) 310 return; 311 312 ASSERT(db->db_objset != NULL); 313 DB_DNODE_ENTER(db); 314 dn = DB_DNODE(db); 315 if (dn == NULL) { 316 ASSERT(db->db_parent == NULL); 317 ASSERT(db->db_blkptr == NULL); 318 } else { 319 ASSERT3U(db->db.db_object, ==, dn->dn_object); 320 ASSERT3P(db->db_objset, ==, dn->dn_objset); 321 ASSERT3U(db->db_level, <, dn->dn_nlevels); 322 ASSERT(db->db_blkid == DMU_BONUS_BLKID || 323 db->db_blkid == DMU_SPILL_BLKID || 324 !list_is_empty(&dn->dn_dbufs)); 325 } 326 if (db->db_blkid == DMU_BONUS_BLKID) { 327 ASSERT(dn != NULL); 328 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 329 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID); 330 } else if (db->db_blkid == DMU_SPILL_BLKID) { 331 ASSERT(dn != NULL); 332 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 333 ASSERT0(db->db.db_offset); 334 } else { 335 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size); 336 } 337 338 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next) 339 ASSERT(dr->dr_dbuf == db); 340 341 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next) 342 ASSERT(dr->dr_dbuf == db); 343 344 /* 345 * We can't assert that db_size matches dn_datablksz because it 346 * can be momentarily different when another thread is doing 347 * dnode_set_blksz(). 348 */ 349 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) { 350 dr = db->db_data_pending; 351 /* 352 * It should only be modified in syncing context, so 353 * make sure we only have one copy of the data. 354 */ 355 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf); 356 } 357 358 /* verify db->db_blkptr */ 359 if (db->db_blkptr) { 360 if (db->db_parent == dn->dn_dbuf) { 361 /* db is pointed to by the dnode */ 362 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */ 363 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object)) 364 ASSERT(db->db_parent == NULL); 365 else 366 ASSERT(db->db_parent != NULL); 367 if (db->db_blkid != DMU_SPILL_BLKID) 368 ASSERT3P(db->db_blkptr, ==, 369 &dn->dn_phys->dn_blkptr[db->db_blkid]); 370 } else { 371 /* db is pointed to by an indirect block */ 372 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT; 373 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1); 374 ASSERT3U(db->db_parent->db.db_object, ==, 375 db->db.db_object); 376 /* 377 * dnode_grow_indblksz() can make this fail if we don't 378 * have the struct_rwlock. XXX indblksz no longer 379 * grows. safe to do this now? 380 */ 381 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 382 ASSERT3P(db->db_blkptr, ==, 383 ((blkptr_t *)db->db_parent->db.db_data + 384 db->db_blkid % epb)); 385 } 386 } 387 } 388 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) && 389 (db->db_buf == NULL || db->db_buf->b_data) && 390 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID && 391 db->db_state != DB_FILL && !dn->dn_free_txg) { 392 /* 393 * If the blkptr isn't set but they have nonzero data, 394 * it had better be dirty, otherwise we'll lose that 395 * data when we evict this buffer. 396 */ 397 if (db->db_dirtycnt == 0) { 398 uint64_t *buf = db->db.db_data; 399 int i; 400 401 for (i = 0; i < db->db.db_size >> 3; i++) { 402 ASSERT(buf[i] == 0); 403 } 404 } 405 } 406 DB_DNODE_EXIT(db); 407 } 408 #endif 409 410 static void 411 dbuf_update_data(dmu_buf_impl_t *db) 412 { 413 ASSERT(MUTEX_HELD(&db->db_mtx)); 414 if (db->db_level == 0 && db->db_user_data_ptr_ptr) { 415 ASSERT(!refcount_is_zero(&db->db_holds)); 416 *db->db_user_data_ptr_ptr = db->db.db_data; 417 } 418 } 419 420 static void 421 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf) 422 { 423 ASSERT(MUTEX_HELD(&db->db_mtx)); 424 ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf)); 425 db->db_buf = buf; 426 if (buf != NULL) { 427 ASSERT(buf->b_data != NULL); 428 db->db.db_data = buf->b_data; 429 if (!arc_released(buf)) 430 arc_set_callback(buf, dbuf_do_evict, db); 431 dbuf_update_data(db); 432 } else { 433 dbuf_evict_user(db); 434 db->db.db_data = NULL; 435 if (db->db_state != DB_NOFILL) 436 db->db_state = DB_UNCACHED; 437 } 438 } 439 440 /* 441 * Loan out an arc_buf for read. Return the loaned arc_buf. 442 */ 443 arc_buf_t * 444 dbuf_loan_arcbuf(dmu_buf_impl_t *db) 445 { 446 arc_buf_t *abuf; 447 448 mutex_enter(&db->db_mtx); 449 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) { 450 int blksz = db->db.db_size; 451 spa_t *spa; 452 453 mutex_exit(&db->db_mtx); 454 DB_GET_SPA(&spa, db); 455 abuf = arc_loan_buf(spa, blksz); 456 bcopy(db->db.db_data, abuf->b_data, blksz); 457 } else { 458 abuf = db->db_buf; 459 arc_loan_inuse_buf(abuf, db); 460 dbuf_set_data(db, NULL); 461 mutex_exit(&db->db_mtx); 462 } 463 return (abuf); 464 } 465 466 uint64_t 467 dbuf_whichblock(dnode_t *dn, uint64_t offset) 468 { 469 if (dn->dn_datablkshift) { 470 return (offset >> dn->dn_datablkshift); 471 } else { 472 ASSERT3U(offset, <, dn->dn_datablksz); 473 return (0); 474 } 475 } 476 477 static void 478 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb) 479 { 480 dmu_buf_impl_t *db = vdb; 481 482 mutex_enter(&db->db_mtx); 483 ASSERT3U(db->db_state, ==, DB_READ); 484 /* 485 * All reads are synchronous, so we must have a hold on the dbuf 486 */ 487 ASSERT(refcount_count(&db->db_holds) > 0); 488 ASSERT(db->db_buf == NULL); 489 ASSERT(db->db.db_data == NULL); 490 if (db->db_level == 0 && db->db_freed_in_flight) { 491 /* we were freed in flight; disregard any error */ 492 arc_release(buf, db); 493 bzero(buf->b_data, db->db.db_size); 494 arc_buf_freeze(buf); 495 db->db_freed_in_flight = FALSE; 496 dbuf_set_data(db, buf); 497 db->db_state = DB_CACHED; 498 } else if (zio == NULL || zio->io_error == 0) { 499 dbuf_set_data(db, buf); 500 db->db_state = DB_CACHED; 501 } else { 502 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 503 ASSERT3P(db->db_buf, ==, NULL); 504 VERIFY(arc_buf_remove_ref(buf, db)); 505 db->db_state = DB_UNCACHED; 506 } 507 cv_broadcast(&db->db_changed); 508 dbuf_rele_and_unlock(db, NULL); 509 } 510 511 static void 512 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags) 513 { 514 dnode_t *dn; 515 spa_t *spa; 516 zbookmark_t zb; 517 uint32_t aflags = ARC_NOWAIT; 518 519 DB_DNODE_ENTER(db); 520 dn = DB_DNODE(db); 521 ASSERT(!refcount_is_zero(&db->db_holds)); 522 /* We need the struct_rwlock to prevent db_blkptr from changing. */ 523 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 524 ASSERT(MUTEX_HELD(&db->db_mtx)); 525 ASSERT(db->db_state == DB_UNCACHED); 526 ASSERT(db->db_buf == NULL); 527 528 if (db->db_blkid == DMU_BONUS_BLKID) { 529 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen); 530 531 ASSERT3U(bonuslen, <=, db->db.db_size); 532 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN); 533 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 534 if (bonuslen < DN_MAX_BONUSLEN) 535 bzero(db->db.db_data, DN_MAX_BONUSLEN); 536 if (bonuslen) 537 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen); 538 DB_DNODE_EXIT(db); 539 dbuf_update_data(db); 540 db->db_state = DB_CACHED; 541 mutex_exit(&db->db_mtx); 542 return; 543 } 544 545 /* 546 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync() 547 * processes the delete record and clears the bp while we are waiting 548 * for the dn_mtx (resulting in a "no" from block_freed). 549 */ 550 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) || 551 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) || 552 BP_IS_HOLE(db->db_blkptr)))) { 553 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 554 555 dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa, 556 db->db.db_size, db, type)); 557 DB_DNODE_EXIT(db); 558 bzero(db->db.db_data, db->db.db_size); 559 db->db_state = DB_CACHED; 560 *flags |= DB_RF_CACHED; 561 mutex_exit(&db->db_mtx); 562 return; 563 } 564 565 spa = dn->dn_objset->os_spa; 566 DB_DNODE_EXIT(db); 567 568 db->db_state = DB_READ; 569 mutex_exit(&db->db_mtx); 570 571 if (DBUF_IS_L2CACHEABLE(db)) 572 aflags |= ARC_L2CACHE; 573 if (DBUF_IS_L2COMPRESSIBLE(db)) 574 aflags |= ARC_L2COMPRESS; 575 576 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ? 577 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET, 578 db->db.db_object, db->db_level, db->db_blkid); 579 580 dbuf_add_ref(db, NULL); 581 582 (void) arc_read(zio, spa, db->db_blkptr, 583 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ, 584 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED, 585 &aflags, &zb); 586 if (aflags & ARC_CACHED) 587 *flags |= DB_RF_CACHED; 588 } 589 590 int 591 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) 592 { 593 int err = 0; 594 int havepzio = (zio != NULL); 595 int prefetch; 596 dnode_t *dn; 597 598 /* 599 * We don't have to hold the mutex to check db_state because it 600 * can't be freed while we have a hold on the buffer. 601 */ 602 ASSERT(!refcount_is_zero(&db->db_holds)); 603 604 if (db->db_state == DB_NOFILL) 605 return (SET_ERROR(EIO)); 606 607 DB_DNODE_ENTER(db); 608 dn = DB_DNODE(db); 609 if ((flags & DB_RF_HAVESTRUCT) == 0) 610 rw_enter(&dn->dn_struct_rwlock, RW_READER); 611 612 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 613 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL && 614 DBUF_IS_CACHEABLE(db); 615 616 mutex_enter(&db->db_mtx); 617 if (db->db_state == DB_CACHED) { 618 mutex_exit(&db->db_mtx); 619 if (prefetch) 620 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 621 db->db.db_size, TRUE); 622 if ((flags & DB_RF_HAVESTRUCT) == 0) 623 rw_exit(&dn->dn_struct_rwlock); 624 DB_DNODE_EXIT(db); 625 } else if (db->db_state == DB_UNCACHED) { 626 spa_t *spa = dn->dn_objset->os_spa; 627 628 if (zio == NULL) 629 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL); 630 dbuf_read_impl(db, zio, &flags); 631 632 /* dbuf_read_impl has dropped db_mtx for us */ 633 634 if (prefetch) 635 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 636 db->db.db_size, flags & DB_RF_CACHED); 637 638 if ((flags & DB_RF_HAVESTRUCT) == 0) 639 rw_exit(&dn->dn_struct_rwlock); 640 DB_DNODE_EXIT(db); 641 642 if (!havepzio) 643 err = zio_wait(zio); 644 } else { 645 /* 646 * Another reader came in while the dbuf was in flight 647 * between UNCACHED and CACHED. Either a writer will finish 648 * writing the buffer (sending the dbuf to CACHED) or the 649 * first reader's request will reach the read_done callback 650 * and send the dbuf to CACHED. Otherwise, a failure 651 * occurred and the dbuf went to UNCACHED. 652 */ 653 mutex_exit(&db->db_mtx); 654 if (prefetch) 655 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset, 656 db->db.db_size, TRUE); 657 if ((flags & DB_RF_HAVESTRUCT) == 0) 658 rw_exit(&dn->dn_struct_rwlock); 659 DB_DNODE_EXIT(db); 660 661 /* Skip the wait per the caller's request. */ 662 mutex_enter(&db->db_mtx); 663 if ((flags & DB_RF_NEVERWAIT) == 0) { 664 while (db->db_state == DB_READ || 665 db->db_state == DB_FILL) { 666 ASSERT(db->db_state == DB_READ || 667 (flags & DB_RF_HAVESTRUCT) == 0); 668 cv_wait(&db->db_changed, &db->db_mtx); 669 } 670 if (db->db_state == DB_UNCACHED) 671 err = SET_ERROR(EIO); 672 } 673 mutex_exit(&db->db_mtx); 674 } 675 676 ASSERT(err || havepzio || db->db_state == DB_CACHED); 677 return (err); 678 } 679 680 static void 681 dbuf_noread(dmu_buf_impl_t *db) 682 { 683 ASSERT(!refcount_is_zero(&db->db_holds)); 684 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 685 mutex_enter(&db->db_mtx); 686 while (db->db_state == DB_READ || db->db_state == DB_FILL) 687 cv_wait(&db->db_changed, &db->db_mtx); 688 if (db->db_state == DB_UNCACHED) { 689 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 690 spa_t *spa; 691 692 ASSERT(db->db_buf == NULL); 693 ASSERT(db->db.db_data == NULL); 694 DB_GET_SPA(&spa, db); 695 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type)); 696 db->db_state = DB_FILL; 697 } else if (db->db_state == DB_NOFILL) { 698 dbuf_set_data(db, NULL); 699 } else { 700 ASSERT3U(db->db_state, ==, DB_CACHED); 701 } 702 mutex_exit(&db->db_mtx); 703 } 704 705 /* 706 * This is our just-in-time copy function. It makes a copy of 707 * buffers, that have been modified in a previous transaction 708 * group, before we modify them in the current active group. 709 * 710 * This function is used in two places: when we are dirtying a 711 * buffer for the first time in a txg, and when we are freeing 712 * a range in a dnode that includes this buffer. 713 * 714 * Note that when we are called from dbuf_free_range() we do 715 * not put a hold on the buffer, we just traverse the active 716 * dbuf list for the dnode. 717 */ 718 static void 719 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg) 720 { 721 dbuf_dirty_record_t *dr = db->db_last_dirty; 722 723 ASSERT(MUTEX_HELD(&db->db_mtx)); 724 ASSERT(db->db.db_data != NULL); 725 ASSERT(db->db_level == 0); 726 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT); 727 728 if (dr == NULL || 729 (dr->dt.dl.dr_data != 730 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf))) 731 return; 732 733 /* 734 * If the last dirty record for this dbuf has not yet synced 735 * and its referencing the dbuf data, either: 736 * reset the reference to point to a new copy, 737 * or (if there a no active holders) 738 * just null out the current db_data pointer. 739 */ 740 ASSERT(dr->dr_txg >= txg - 2); 741 if (db->db_blkid == DMU_BONUS_BLKID) { 742 /* Note that the data bufs here are zio_bufs */ 743 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN); 744 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 745 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN); 746 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) { 747 int size = db->db.db_size; 748 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 749 spa_t *spa; 750 751 DB_GET_SPA(&spa, db); 752 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type); 753 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size); 754 } else { 755 dbuf_set_data(db, NULL); 756 } 757 } 758 759 void 760 dbuf_unoverride(dbuf_dirty_record_t *dr) 761 { 762 dmu_buf_impl_t *db = dr->dr_dbuf; 763 blkptr_t *bp = &dr->dt.dl.dr_overridden_by; 764 uint64_t txg = dr->dr_txg; 765 766 ASSERT(MUTEX_HELD(&db->db_mtx)); 767 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC); 768 ASSERT(db->db_level == 0); 769 770 if (db->db_blkid == DMU_BONUS_BLKID || 771 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN) 772 return; 773 774 ASSERT(db->db_data_pending != dr); 775 776 /* free this block */ 777 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite) { 778 spa_t *spa; 779 780 DB_GET_SPA(&spa, db); 781 zio_free(spa, txg, bp); 782 } 783 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 784 dr->dt.dl.dr_nopwrite = B_FALSE; 785 786 /* 787 * Release the already-written buffer, so we leave it in 788 * a consistent dirty state. Note that all callers are 789 * modifying the buffer, so they will immediately do 790 * another (redundant) arc_release(). Therefore, leave 791 * the buf thawed to save the effort of freezing & 792 * immediately re-thawing it. 793 */ 794 arc_release(dr->dt.dl.dr_data, db); 795 } 796 797 /* 798 * Evict (if its unreferenced) or clear (if its referenced) any level-0 799 * data blocks in the free range, so that any future readers will find 800 * empty blocks. Also, if we happen across any level-1 dbufs in the 801 * range that have not already been marked dirty, mark them dirty so 802 * they stay in memory. 803 * 804 * This is a no-op if the dataset is in the middle of an incremental 805 * receive; see comment below for details. 806 */ 807 void 808 dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx) 809 { 810 dmu_buf_impl_t *db, *db_next; 811 uint64_t txg = tx->tx_txg; 812 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 813 uint64_t first_l1 = start >> epbs; 814 uint64_t last_l1 = end >> epbs; 815 816 if (end > dn->dn_maxblkid && (end != DMU_SPILL_BLKID)) { 817 end = dn->dn_maxblkid; 818 last_l1 = end >> epbs; 819 } 820 dprintf_dnode(dn, "start=%llu end=%llu\n", start, end); 821 822 if (dmu_objset_is_receiving(dn->dn_objset)) { 823 /* 824 * When processing a free record from a zfs receive, 825 * there should have been no previous modifications to the 826 * data in this range. Therefore there should be no dbufs 827 * in the range. Searching dn_dbufs for these non-existent 828 * dbufs can be very expensive, so simply ignore this. 829 */ 830 VERIFY3P(dbuf_find(dn, 0, start), ==, NULL); 831 VERIFY3P(dbuf_find(dn, 0, end), ==, NULL); 832 return; 833 } 834 835 mutex_enter(&dn->dn_dbufs_mtx); 836 for (db = list_head(&dn->dn_dbufs); db; db = db_next) { 837 db_next = list_next(&dn->dn_dbufs, db); 838 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 839 840 if (db->db_level == 1 && 841 db->db_blkid >= first_l1 && db->db_blkid <= last_l1) { 842 mutex_enter(&db->db_mtx); 843 if (db->db_last_dirty && 844 db->db_last_dirty->dr_txg < txg) { 845 dbuf_add_ref(db, FTAG); 846 mutex_exit(&db->db_mtx); 847 dbuf_will_dirty(db, tx); 848 dbuf_rele(db, FTAG); 849 } else { 850 mutex_exit(&db->db_mtx); 851 } 852 } 853 854 if (db->db_level != 0) 855 continue; 856 dprintf_dbuf(db, "found buf %s\n", ""); 857 if (db->db_blkid < start || db->db_blkid > end) 858 continue; 859 860 /* found a level 0 buffer in the range */ 861 mutex_enter(&db->db_mtx); 862 if (dbuf_undirty(db, tx)) { 863 /* mutex has been dropped and dbuf destroyed */ 864 continue; 865 } 866 867 if (db->db_state == DB_UNCACHED || 868 db->db_state == DB_NOFILL || 869 db->db_state == DB_EVICTING) { 870 ASSERT(db->db.db_data == NULL); 871 mutex_exit(&db->db_mtx); 872 continue; 873 } 874 if (db->db_state == DB_READ || db->db_state == DB_FILL) { 875 /* will be handled in dbuf_read_done or dbuf_rele */ 876 db->db_freed_in_flight = TRUE; 877 mutex_exit(&db->db_mtx); 878 continue; 879 } 880 if (refcount_count(&db->db_holds) == 0) { 881 ASSERT(db->db_buf); 882 dbuf_clear(db); 883 continue; 884 } 885 /* The dbuf is referenced */ 886 887 if (db->db_last_dirty != NULL) { 888 dbuf_dirty_record_t *dr = db->db_last_dirty; 889 890 if (dr->dr_txg == txg) { 891 /* 892 * This buffer is "in-use", re-adjust the file 893 * size to reflect that this buffer may 894 * contain new data when we sync. 895 */ 896 if (db->db_blkid != DMU_SPILL_BLKID && 897 db->db_blkid > dn->dn_maxblkid) 898 dn->dn_maxblkid = db->db_blkid; 899 dbuf_unoverride(dr); 900 } else { 901 /* 902 * This dbuf is not dirty in the open context. 903 * Either uncache it (if its not referenced in 904 * the open context) or reset its contents to 905 * empty. 906 */ 907 dbuf_fix_old_data(db, txg); 908 } 909 } 910 /* clear the contents if its cached */ 911 if (db->db_state == DB_CACHED) { 912 ASSERT(db->db.db_data != NULL); 913 arc_release(db->db_buf, db); 914 bzero(db->db.db_data, db->db.db_size); 915 arc_buf_freeze(db->db_buf); 916 } 917 918 mutex_exit(&db->db_mtx); 919 } 920 mutex_exit(&dn->dn_dbufs_mtx); 921 } 922 923 static int 924 dbuf_block_freeable(dmu_buf_impl_t *db) 925 { 926 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset; 927 uint64_t birth_txg = 0; 928 929 /* 930 * We don't need any locking to protect db_blkptr: 931 * If it's syncing, then db_last_dirty will be set 932 * so we'll ignore db_blkptr. 933 */ 934 ASSERT(MUTEX_HELD(&db->db_mtx)); 935 if (db->db_last_dirty) 936 birth_txg = db->db_last_dirty->dr_txg; 937 else if (db->db_blkptr) 938 birth_txg = db->db_blkptr->blk_birth; 939 940 /* 941 * If we don't exist or are in a snapshot, we can't be freed. 942 * Don't pass the bp to dsl_dataset_block_freeable() since we 943 * are holding the db_mtx lock and might deadlock if we are 944 * prefetching a dedup-ed block. 945 */ 946 if (birth_txg) 947 return (ds == NULL || 948 dsl_dataset_block_freeable(ds, NULL, birth_txg)); 949 else 950 return (FALSE); 951 } 952 953 void 954 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx) 955 { 956 arc_buf_t *buf, *obuf; 957 int osize = db->db.db_size; 958 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 959 dnode_t *dn; 960 961 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 962 963 DB_DNODE_ENTER(db); 964 dn = DB_DNODE(db); 965 966 /* XXX does *this* func really need the lock? */ 967 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 968 969 /* 970 * This call to dbuf_will_dirty() with the dn_struct_rwlock held 971 * is OK, because there can be no other references to the db 972 * when we are changing its size, so no concurrent DB_FILL can 973 * be happening. 974 */ 975 /* 976 * XXX we should be doing a dbuf_read, checking the return 977 * value and returning that up to our callers 978 */ 979 dbuf_will_dirty(db, tx); 980 981 /* create the data buffer for the new block */ 982 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type); 983 984 /* copy old block data to the new block */ 985 obuf = db->db_buf; 986 bcopy(obuf->b_data, buf->b_data, MIN(osize, size)); 987 /* zero the remainder */ 988 if (size > osize) 989 bzero((uint8_t *)buf->b_data + osize, size - osize); 990 991 mutex_enter(&db->db_mtx); 992 dbuf_set_data(db, buf); 993 VERIFY(arc_buf_remove_ref(obuf, db)); 994 db->db.db_size = size; 995 996 if (db->db_level == 0) { 997 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 998 db->db_last_dirty->dt.dl.dr_data = buf; 999 } 1000 mutex_exit(&db->db_mtx); 1001 1002 dnode_willuse_space(dn, size-osize, tx); 1003 DB_DNODE_EXIT(db); 1004 } 1005 1006 void 1007 dbuf_release_bp(dmu_buf_impl_t *db) 1008 { 1009 objset_t *os; 1010 1011 DB_GET_OBJSET(&os, db); 1012 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os))); 1013 ASSERT(arc_released(os->os_phys_buf) || 1014 list_link_active(&os->os_dsl_dataset->ds_synced_link)); 1015 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf)); 1016 1017 (void) arc_release(db->db_buf, db); 1018 } 1019 1020 dbuf_dirty_record_t * 1021 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1022 { 1023 dnode_t *dn; 1024 objset_t *os; 1025 dbuf_dirty_record_t **drp, *dr; 1026 int drop_struct_lock = FALSE; 1027 boolean_t do_free_accounting = B_FALSE; 1028 int txgoff = tx->tx_txg & TXG_MASK; 1029 1030 ASSERT(tx->tx_txg != 0); 1031 ASSERT(!refcount_is_zero(&db->db_holds)); 1032 DMU_TX_DIRTY_BUF(tx, db); 1033 1034 DB_DNODE_ENTER(db); 1035 dn = DB_DNODE(db); 1036 /* 1037 * Shouldn't dirty a regular buffer in syncing context. Private 1038 * objects may be dirtied in syncing context, but only if they 1039 * were already pre-dirtied in open context. 1040 */ 1041 ASSERT(!dmu_tx_is_syncing(tx) || 1042 BP_IS_HOLE(dn->dn_objset->os_rootbp) || 1043 DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1044 dn->dn_objset->os_dsl_dataset == NULL); 1045 /* 1046 * We make this assert for private objects as well, but after we 1047 * check if we're already dirty. They are allowed to re-dirty 1048 * in syncing context. 1049 */ 1050 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1051 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1052 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1053 1054 mutex_enter(&db->db_mtx); 1055 /* 1056 * XXX make this true for indirects too? The problem is that 1057 * transactions created with dmu_tx_create_assigned() from 1058 * syncing context don't bother holding ahead. 1059 */ 1060 ASSERT(db->db_level != 0 || 1061 db->db_state == DB_CACHED || db->db_state == DB_FILL || 1062 db->db_state == DB_NOFILL); 1063 1064 mutex_enter(&dn->dn_mtx); 1065 /* 1066 * Don't set dirtyctx to SYNC if we're just modifying this as we 1067 * initialize the objset. 1068 */ 1069 if (dn->dn_dirtyctx == DN_UNDIRTIED && 1070 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) { 1071 dn->dn_dirtyctx = 1072 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN); 1073 ASSERT(dn->dn_dirtyctx_firstset == NULL); 1074 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP); 1075 } 1076 mutex_exit(&dn->dn_mtx); 1077 1078 if (db->db_blkid == DMU_SPILL_BLKID) 1079 dn->dn_have_spill = B_TRUE; 1080 1081 /* 1082 * If this buffer is already dirty, we're done. 1083 */ 1084 drp = &db->db_last_dirty; 1085 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg || 1086 db->db.db_object == DMU_META_DNODE_OBJECT); 1087 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg) 1088 drp = &dr->dr_next; 1089 if (dr && dr->dr_txg == tx->tx_txg) { 1090 DB_DNODE_EXIT(db); 1091 1092 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) { 1093 /* 1094 * If this buffer has already been written out, 1095 * we now need to reset its state. 1096 */ 1097 dbuf_unoverride(dr); 1098 if (db->db.db_object != DMU_META_DNODE_OBJECT && 1099 db->db_state != DB_NOFILL) 1100 arc_buf_thaw(db->db_buf); 1101 } 1102 mutex_exit(&db->db_mtx); 1103 return (dr); 1104 } 1105 1106 /* 1107 * Only valid if not already dirty. 1108 */ 1109 ASSERT(dn->dn_object == 0 || 1110 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1111 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1112 1113 ASSERT3U(dn->dn_nlevels, >, db->db_level); 1114 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) || 1115 dn->dn_phys->dn_nlevels > db->db_level || 1116 dn->dn_next_nlevels[txgoff] > db->db_level || 1117 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level || 1118 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level); 1119 1120 /* 1121 * We should only be dirtying in syncing context if it's the 1122 * mos or we're initializing the os or it's a special object. 1123 * However, we are allowed to dirty in syncing context provided 1124 * we already dirtied it in open context. Hence we must make 1125 * this assertion only if we're not already dirty. 1126 */ 1127 os = dn->dn_objset; 1128 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1129 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp)); 1130 ASSERT(db->db.db_size != 0); 1131 1132 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1133 1134 if (db->db_blkid != DMU_BONUS_BLKID) { 1135 /* 1136 * Update the accounting. 1137 * Note: we delay "free accounting" until after we drop 1138 * the db_mtx. This keeps us from grabbing other locks 1139 * (and possibly deadlocking) in bp_get_dsize() while 1140 * also holding the db_mtx. 1141 */ 1142 dnode_willuse_space(dn, db->db.db_size, tx); 1143 do_free_accounting = dbuf_block_freeable(db); 1144 } 1145 1146 /* 1147 * If this buffer is dirty in an old transaction group we need 1148 * to make a copy of it so that the changes we make in this 1149 * transaction group won't leak out when we sync the older txg. 1150 */ 1151 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP); 1152 if (db->db_level == 0) { 1153 void *data_old = db->db_buf; 1154 1155 if (db->db_state != DB_NOFILL) { 1156 if (db->db_blkid == DMU_BONUS_BLKID) { 1157 dbuf_fix_old_data(db, tx->tx_txg); 1158 data_old = db->db.db_data; 1159 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) { 1160 /* 1161 * Release the data buffer from the cache so 1162 * that we can modify it without impacting 1163 * possible other users of this cached data 1164 * block. Note that indirect blocks and 1165 * private objects are not released until the 1166 * syncing state (since they are only modified 1167 * then). 1168 */ 1169 arc_release(db->db_buf, db); 1170 dbuf_fix_old_data(db, tx->tx_txg); 1171 data_old = db->db_buf; 1172 } 1173 ASSERT(data_old != NULL); 1174 } 1175 dr->dt.dl.dr_data = data_old; 1176 } else { 1177 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL); 1178 list_create(&dr->dt.di.dr_children, 1179 sizeof (dbuf_dirty_record_t), 1180 offsetof(dbuf_dirty_record_t, dr_dirty_node)); 1181 } 1182 dr->dr_dbuf = db; 1183 dr->dr_txg = tx->tx_txg; 1184 dr->dr_next = *drp; 1185 *drp = dr; 1186 1187 /* 1188 * We could have been freed_in_flight between the dbuf_noread 1189 * and dbuf_dirty. We win, as though the dbuf_noread() had 1190 * happened after the free. 1191 */ 1192 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1193 db->db_blkid != DMU_SPILL_BLKID) { 1194 mutex_enter(&dn->dn_mtx); 1195 dnode_clear_range(dn, db->db_blkid, 1, tx); 1196 mutex_exit(&dn->dn_mtx); 1197 db->db_freed_in_flight = FALSE; 1198 } 1199 1200 /* 1201 * This buffer is now part of this txg 1202 */ 1203 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg); 1204 db->db_dirtycnt += 1; 1205 ASSERT3U(db->db_dirtycnt, <=, 3); 1206 1207 mutex_exit(&db->db_mtx); 1208 1209 if (db->db_blkid == DMU_BONUS_BLKID || 1210 db->db_blkid == DMU_SPILL_BLKID) { 1211 mutex_enter(&dn->dn_mtx); 1212 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1213 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1214 mutex_exit(&dn->dn_mtx); 1215 dnode_setdirty(dn, tx); 1216 DB_DNODE_EXIT(db); 1217 return (dr); 1218 } else if (do_free_accounting) { 1219 blkptr_t *bp = db->db_blkptr; 1220 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ? 1221 bp_get_dsize(os->os_spa, bp) : db->db.db_size; 1222 /* 1223 * This is only a guess -- if the dbuf is dirty 1224 * in a previous txg, we don't know how much 1225 * space it will use on disk yet. We should 1226 * really have the struct_rwlock to access 1227 * db_blkptr, but since this is just a guess, 1228 * it's OK if we get an odd answer. 1229 */ 1230 ddt_prefetch(os->os_spa, bp); 1231 dnode_willuse_space(dn, -willfree, tx); 1232 } 1233 1234 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 1235 rw_enter(&dn->dn_struct_rwlock, RW_READER); 1236 drop_struct_lock = TRUE; 1237 } 1238 1239 if (db->db_level == 0) { 1240 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock); 1241 ASSERT(dn->dn_maxblkid >= db->db_blkid); 1242 } 1243 1244 if (db->db_level+1 < dn->dn_nlevels) { 1245 dmu_buf_impl_t *parent = db->db_parent; 1246 dbuf_dirty_record_t *di; 1247 int parent_held = FALSE; 1248 1249 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) { 1250 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1251 1252 parent = dbuf_hold_level(dn, db->db_level+1, 1253 db->db_blkid >> epbs, FTAG); 1254 ASSERT(parent != NULL); 1255 parent_held = TRUE; 1256 } 1257 if (drop_struct_lock) 1258 rw_exit(&dn->dn_struct_rwlock); 1259 ASSERT3U(db->db_level+1, ==, parent->db_level); 1260 di = dbuf_dirty(parent, tx); 1261 if (parent_held) 1262 dbuf_rele(parent, FTAG); 1263 1264 mutex_enter(&db->db_mtx); 1265 /* possible race with dbuf_undirty() */ 1266 if (db->db_last_dirty == dr || 1267 dn->dn_object == DMU_META_DNODE_OBJECT) { 1268 mutex_enter(&di->dt.di.dr_mtx); 1269 ASSERT3U(di->dr_txg, ==, tx->tx_txg); 1270 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1271 list_insert_tail(&di->dt.di.dr_children, dr); 1272 mutex_exit(&di->dt.di.dr_mtx); 1273 dr->dr_parent = di; 1274 } 1275 mutex_exit(&db->db_mtx); 1276 } else { 1277 ASSERT(db->db_level+1 == dn->dn_nlevels); 1278 ASSERT(db->db_blkid < dn->dn_nblkptr); 1279 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf); 1280 mutex_enter(&dn->dn_mtx); 1281 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1282 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1283 mutex_exit(&dn->dn_mtx); 1284 if (drop_struct_lock) 1285 rw_exit(&dn->dn_struct_rwlock); 1286 } 1287 1288 dnode_setdirty(dn, tx); 1289 DB_DNODE_EXIT(db); 1290 return (dr); 1291 } 1292 1293 /* 1294 * Undirty a buffer in the transaction group referenced by the given 1295 * transaction. Return whether this evicted the dbuf. 1296 */ 1297 static boolean_t 1298 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1299 { 1300 dnode_t *dn; 1301 uint64_t txg = tx->tx_txg; 1302 dbuf_dirty_record_t *dr, **drp; 1303 1304 ASSERT(txg != 0); 1305 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1306 ASSERT0(db->db_level); 1307 ASSERT(MUTEX_HELD(&db->db_mtx)); 1308 1309 /* 1310 * If this buffer is not dirty, we're done. 1311 */ 1312 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next) 1313 if (dr->dr_txg <= txg) 1314 break; 1315 if (dr == NULL || dr->dr_txg < txg) 1316 return (B_FALSE); 1317 ASSERT(dr->dr_txg == txg); 1318 ASSERT(dr->dr_dbuf == db); 1319 1320 DB_DNODE_ENTER(db); 1321 dn = DB_DNODE(db); 1322 1323 /* 1324 * Note: This code will probably work even if there are concurrent 1325 * holders, but it is untested in that scenerio, as the ZPL and 1326 * ztest have additional locking (the range locks) that prevents 1327 * that type of concurrent access. 1328 */ 1329 ASSERT3U(refcount_count(&db->db_holds), ==, db->db_dirtycnt); 1330 1331 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1332 1333 ASSERT(db->db.db_size != 0); 1334 1335 /* XXX would be nice to fix up dn_towrite_space[] */ 1336 1337 *drp = dr->dr_next; 1338 1339 /* 1340 * Note that there are three places in dbuf_dirty() 1341 * where this dirty record may be put on a list. 1342 * Make sure to do a list_remove corresponding to 1343 * every one of those list_insert calls. 1344 */ 1345 if (dr->dr_parent) { 1346 mutex_enter(&dr->dr_parent->dt.di.dr_mtx); 1347 list_remove(&dr->dr_parent->dt.di.dr_children, dr); 1348 mutex_exit(&dr->dr_parent->dt.di.dr_mtx); 1349 } else if (db->db_blkid == DMU_SPILL_BLKID || 1350 db->db_level+1 == dn->dn_nlevels) { 1351 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf); 1352 mutex_enter(&dn->dn_mtx); 1353 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr); 1354 mutex_exit(&dn->dn_mtx); 1355 } 1356 DB_DNODE_EXIT(db); 1357 1358 if (db->db_state != DB_NOFILL) { 1359 dbuf_unoverride(dr); 1360 1361 ASSERT(db->db_buf != NULL); 1362 ASSERT(dr->dt.dl.dr_data != NULL); 1363 if (dr->dt.dl.dr_data != db->db_buf) 1364 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db)); 1365 } 1366 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 1367 1368 ASSERT(db->db_dirtycnt > 0); 1369 db->db_dirtycnt -= 1; 1370 1371 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) { 1372 arc_buf_t *buf = db->db_buf; 1373 1374 ASSERT(db->db_state == DB_NOFILL || arc_released(buf)); 1375 dbuf_set_data(db, NULL); 1376 VERIFY(arc_buf_remove_ref(buf, db)); 1377 dbuf_evict(db); 1378 return (B_TRUE); 1379 } 1380 1381 return (B_FALSE); 1382 } 1383 1384 #pragma weak dmu_buf_will_dirty = dbuf_will_dirty 1385 void 1386 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1387 { 1388 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH; 1389 1390 ASSERT(tx->tx_txg != 0); 1391 ASSERT(!refcount_is_zero(&db->db_holds)); 1392 1393 DB_DNODE_ENTER(db); 1394 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock)) 1395 rf |= DB_RF_HAVESTRUCT; 1396 DB_DNODE_EXIT(db); 1397 (void) dbuf_read(db, NULL, rf); 1398 (void) dbuf_dirty(db, tx); 1399 } 1400 1401 void 1402 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1403 { 1404 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1405 1406 db->db_state = DB_NOFILL; 1407 1408 dmu_buf_will_fill(db_fake, tx); 1409 } 1410 1411 void 1412 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1413 { 1414 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1415 1416 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1417 ASSERT(tx->tx_txg != 0); 1418 ASSERT(db->db_level == 0); 1419 ASSERT(!refcount_is_zero(&db->db_holds)); 1420 1421 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT || 1422 dmu_tx_private_ok(tx)); 1423 1424 dbuf_noread(db); 1425 (void) dbuf_dirty(db, tx); 1426 } 1427 1428 #pragma weak dmu_buf_fill_done = dbuf_fill_done 1429 /* ARGSUSED */ 1430 void 1431 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx) 1432 { 1433 mutex_enter(&db->db_mtx); 1434 DBUF_VERIFY(db); 1435 1436 if (db->db_state == DB_FILL) { 1437 if (db->db_level == 0 && db->db_freed_in_flight) { 1438 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1439 /* we were freed while filling */ 1440 /* XXX dbuf_undirty? */ 1441 bzero(db->db.db_data, db->db.db_size); 1442 db->db_freed_in_flight = FALSE; 1443 } 1444 db->db_state = DB_CACHED; 1445 cv_broadcast(&db->db_changed); 1446 } 1447 mutex_exit(&db->db_mtx); 1448 } 1449 1450 /* 1451 * Directly assign a provided arc buf to a given dbuf if it's not referenced 1452 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf. 1453 */ 1454 void 1455 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx) 1456 { 1457 ASSERT(!refcount_is_zero(&db->db_holds)); 1458 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1459 ASSERT(db->db_level == 0); 1460 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA); 1461 ASSERT(buf != NULL); 1462 ASSERT(arc_buf_size(buf) == db->db.db_size); 1463 ASSERT(tx->tx_txg != 0); 1464 1465 arc_return_buf(buf, db); 1466 ASSERT(arc_released(buf)); 1467 1468 mutex_enter(&db->db_mtx); 1469 1470 while (db->db_state == DB_READ || db->db_state == DB_FILL) 1471 cv_wait(&db->db_changed, &db->db_mtx); 1472 1473 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED); 1474 1475 if (db->db_state == DB_CACHED && 1476 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) { 1477 mutex_exit(&db->db_mtx); 1478 (void) dbuf_dirty(db, tx); 1479 bcopy(buf->b_data, db->db.db_data, db->db.db_size); 1480 VERIFY(arc_buf_remove_ref(buf, db)); 1481 xuio_stat_wbuf_copied(); 1482 return; 1483 } 1484 1485 xuio_stat_wbuf_nocopy(); 1486 if (db->db_state == DB_CACHED) { 1487 dbuf_dirty_record_t *dr = db->db_last_dirty; 1488 1489 ASSERT(db->db_buf != NULL); 1490 if (dr != NULL && dr->dr_txg == tx->tx_txg) { 1491 ASSERT(dr->dt.dl.dr_data == db->db_buf); 1492 if (!arc_released(db->db_buf)) { 1493 ASSERT(dr->dt.dl.dr_override_state == 1494 DR_OVERRIDDEN); 1495 arc_release(db->db_buf, db); 1496 } 1497 dr->dt.dl.dr_data = buf; 1498 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1499 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) { 1500 arc_release(db->db_buf, db); 1501 VERIFY(arc_buf_remove_ref(db->db_buf, db)); 1502 } 1503 db->db_buf = NULL; 1504 } 1505 ASSERT(db->db_buf == NULL); 1506 dbuf_set_data(db, buf); 1507 db->db_state = DB_FILL; 1508 mutex_exit(&db->db_mtx); 1509 (void) dbuf_dirty(db, tx); 1510 dbuf_fill_done(db, tx); 1511 } 1512 1513 /* 1514 * "Clear" the contents of this dbuf. This will mark the dbuf 1515 * EVICTING and clear *most* of its references. Unfortunetely, 1516 * when we are not holding the dn_dbufs_mtx, we can't clear the 1517 * entry in the dn_dbufs list. We have to wait until dbuf_destroy() 1518 * in this case. For callers from the DMU we will usually see: 1519 * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy() 1520 * For the arc callback, we will usually see: 1521 * dbuf_do_evict()->dbuf_clear();dbuf_destroy() 1522 * Sometimes, though, we will get a mix of these two: 1523 * DMU: dbuf_clear()->arc_buf_evict() 1524 * ARC: dbuf_do_evict()->dbuf_destroy() 1525 */ 1526 void 1527 dbuf_clear(dmu_buf_impl_t *db) 1528 { 1529 dnode_t *dn; 1530 dmu_buf_impl_t *parent = db->db_parent; 1531 dmu_buf_impl_t *dndb; 1532 int dbuf_gone = FALSE; 1533 1534 ASSERT(MUTEX_HELD(&db->db_mtx)); 1535 ASSERT(refcount_is_zero(&db->db_holds)); 1536 1537 dbuf_evict_user(db); 1538 1539 if (db->db_state == DB_CACHED) { 1540 ASSERT(db->db.db_data != NULL); 1541 if (db->db_blkid == DMU_BONUS_BLKID) { 1542 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN); 1543 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 1544 } 1545 db->db.db_data = NULL; 1546 db->db_state = DB_UNCACHED; 1547 } 1548 1549 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL); 1550 ASSERT(db->db_data_pending == NULL); 1551 1552 db->db_state = DB_EVICTING; 1553 db->db_blkptr = NULL; 1554 1555 DB_DNODE_ENTER(db); 1556 dn = DB_DNODE(db); 1557 dndb = dn->dn_dbuf; 1558 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) { 1559 list_remove(&dn->dn_dbufs, db); 1560 (void) atomic_dec_32_nv(&dn->dn_dbufs_count); 1561 membar_producer(); 1562 DB_DNODE_EXIT(db); 1563 /* 1564 * Decrementing the dbuf count means that the hold corresponding 1565 * to the removed dbuf is no longer discounted in dnode_move(), 1566 * so the dnode cannot be moved until after we release the hold. 1567 * The membar_producer() ensures visibility of the decremented 1568 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually 1569 * release any lock. 1570 */ 1571 dnode_rele(dn, db); 1572 db->db_dnode_handle = NULL; 1573 } else { 1574 DB_DNODE_EXIT(db); 1575 } 1576 1577 if (db->db_buf) 1578 dbuf_gone = arc_buf_evict(db->db_buf); 1579 1580 if (!dbuf_gone) 1581 mutex_exit(&db->db_mtx); 1582 1583 /* 1584 * If this dbuf is referenced from an indirect dbuf, 1585 * decrement the ref count on the indirect dbuf. 1586 */ 1587 if (parent && parent != dndb) 1588 dbuf_rele(parent, db); 1589 } 1590 1591 static int 1592 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, 1593 dmu_buf_impl_t **parentp, blkptr_t **bpp) 1594 { 1595 int nlevels, epbs; 1596 1597 *parentp = NULL; 1598 *bpp = NULL; 1599 1600 ASSERT(blkid != DMU_BONUS_BLKID); 1601 1602 if (blkid == DMU_SPILL_BLKID) { 1603 mutex_enter(&dn->dn_mtx); 1604 if (dn->dn_have_spill && 1605 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) 1606 *bpp = &dn->dn_phys->dn_spill; 1607 else 1608 *bpp = NULL; 1609 dbuf_add_ref(dn->dn_dbuf, NULL); 1610 *parentp = dn->dn_dbuf; 1611 mutex_exit(&dn->dn_mtx); 1612 return (0); 1613 } 1614 1615 if (dn->dn_phys->dn_nlevels == 0) 1616 nlevels = 1; 1617 else 1618 nlevels = dn->dn_phys->dn_nlevels; 1619 1620 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1621 1622 ASSERT3U(level * epbs, <, 64); 1623 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1624 if (level >= nlevels || 1625 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) { 1626 /* the buffer has no parent yet */ 1627 return (SET_ERROR(ENOENT)); 1628 } else if (level < nlevels-1) { 1629 /* this block is referenced from an indirect block */ 1630 int err = dbuf_hold_impl(dn, level+1, 1631 blkid >> epbs, fail_sparse, NULL, parentp); 1632 if (err) 1633 return (err); 1634 err = dbuf_read(*parentp, NULL, 1635 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL)); 1636 if (err) { 1637 dbuf_rele(*parentp, NULL); 1638 *parentp = NULL; 1639 return (err); 1640 } 1641 *bpp = ((blkptr_t *)(*parentp)->db.db_data) + 1642 (blkid & ((1ULL << epbs) - 1)); 1643 return (0); 1644 } else { 1645 /* the block is referenced from the dnode */ 1646 ASSERT3U(level, ==, nlevels-1); 1647 ASSERT(dn->dn_phys->dn_nblkptr == 0 || 1648 blkid < dn->dn_phys->dn_nblkptr); 1649 if (dn->dn_dbuf) { 1650 dbuf_add_ref(dn->dn_dbuf, NULL); 1651 *parentp = dn->dn_dbuf; 1652 } 1653 *bpp = &dn->dn_phys->dn_blkptr[blkid]; 1654 return (0); 1655 } 1656 } 1657 1658 static dmu_buf_impl_t * 1659 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid, 1660 dmu_buf_impl_t *parent, blkptr_t *blkptr) 1661 { 1662 objset_t *os = dn->dn_objset; 1663 dmu_buf_impl_t *db, *odb; 1664 1665 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1666 ASSERT(dn->dn_type != DMU_OT_NONE); 1667 1668 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP); 1669 1670 db->db_objset = os; 1671 db->db.db_object = dn->dn_object; 1672 db->db_level = level; 1673 db->db_blkid = blkid; 1674 db->db_last_dirty = NULL; 1675 db->db_dirtycnt = 0; 1676 db->db_dnode_handle = dn->dn_handle; 1677 db->db_parent = parent; 1678 db->db_blkptr = blkptr; 1679 1680 db->db_user_ptr = NULL; 1681 db->db_user_data_ptr_ptr = NULL; 1682 db->db_evict_func = NULL; 1683 db->db_immediate_evict = 0; 1684 db->db_freed_in_flight = 0; 1685 1686 if (blkid == DMU_BONUS_BLKID) { 1687 ASSERT3P(parent, ==, dn->dn_dbuf); 1688 db->db.db_size = DN_MAX_BONUSLEN - 1689 (dn->dn_nblkptr-1) * sizeof (blkptr_t); 1690 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 1691 db->db.db_offset = DMU_BONUS_BLKID; 1692 db->db_state = DB_UNCACHED; 1693 /* the bonus dbuf is not placed in the hash table */ 1694 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1695 return (db); 1696 } else if (blkid == DMU_SPILL_BLKID) { 1697 db->db.db_size = (blkptr != NULL) ? 1698 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE; 1699 db->db.db_offset = 0; 1700 } else { 1701 int blocksize = 1702 db->db_level ? 1<<dn->dn_indblkshift : dn->dn_datablksz; 1703 db->db.db_size = blocksize; 1704 db->db.db_offset = db->db_blkid * blocksize; 1705 } 1706 1707 /* 1708 * Hold the dn_dbufs_mtx while we get the new dbuf 1709 * in the hash table *and* added to the dbufs list. 1710 * This prevents a possible deadlock with someone 1711 * trying to look up this dbuf before its added to the 1712 * dn_dbufs list. 1713 */ 1714 mutex_enter(&dn->dn_dbufs_mtx); 1715 db->db_state = DB_EVICTING; 1716 if ((odb = dbuf_hash_insert(db)) != NULL) { 1717 /* someone else inserted it first */ 1718 kmem_cache_free(dbuf_cache, db); 1719 mutex_exit(&dn->dn_dbufs_mtx); 1720 return (odb); 1721 } 1722 list_insert_head(&dn->dn_dbufs, db); 1723 db->db_state = DB_UNCACHED; 1724 mutex_exit(&dn->dn_dbufs_mtx); 1725 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1726 1727 if (parent && parent != dn->dn_dbuf) 1728 dbuf_add_ref(parent, db); 1729 1730 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1731 refcount_count(&dn->dn_holds) > 0); 1732 (void) refcount_add(&dn->dn_holds, db); 1733 (void) atomic_inc_32_nv(&dn->dn_dbufs_count); 1734 1735 dprintf_dbuf(db, "db=%p\n", db); 1736 1737 return (db); 1738 } 1739 1740 static int 1741 dbuf_do_evict(void *private) 1742 { 1743 arc_buf_t *buf = private; 1744 dmu_buf_impl_t *db = buf->b_private; 1745 1746 if (!MUTEX_HELD(&db->db_mtx)) 1747 mutex_enter(&db->db_mtx); 1748 1749 ASSERT(refcount_is_zero(&db->db_holds)); 1750 1751 if (db->db_state != DB_EVICTING) { 1752 ASSERT(db->db_state == DB_CACHED); 1753 DBUF_VERIFY(db); 1754 db->db_buf = NULL; 1755 dbuf_evict(db); 1756 } else { 1757 mutex_exit(&db->db_mtx); 1758 dbuf_destroy(db); 1759 } 1760 return (0); 1761 } 1762 1763 static void 1764 dbuf_destroy(dmu_buf_impl_t *db) 1765 { 1766 ASSERT(refcount_is_zero(&db->db_holds)); 1767 1768 if (db->db_blkid != DMU_BONUS_BLKID) { 1769 /* 1770 * If this dbuf is still on the dn_dbufs list, 1771 * remove it from that list. 1772 */ 1773 if (db->db_dnode_handle != NULL) { 1774 dnode_t *dn; 1775 1776 DB_DNODE_ENTER(db); 1777 dn = DB_DNODE(db); 1778 mutex_enter(&dn->dn_dbufs_mtx); 1779 list_remove(&dn->dn_dbufs, db); 1780 (void) atomic_dec_32_nv(&dn->dn_dbufs_count); 1781 mutex_exit(&dn->dn_dbufs_mtx); 1782 DB_DNODE_EXIT(db); 1783 /* 1784 * Decrementing the dbuf count means that the hold 1785 * corresponding to the removed dbuf is no longer 1786 * discounted in dnode_move(), so the dnode cannot be 1787 * moved until after we release the hold. 1788 */ 1789 dnode_rele(dn, db); 1790 db->db_dnode_handle = NULL; 1791 } 1792 dbuf_hash_remove(db); 1793 } 1794 db->db_parent = NULL; 1795 db->db_buf = NULL; 1796 1797 ASSERT(!list_link_active(&db->db_link)); 1798 ASSERT(db->db.db_data == NULL); 1799 ASSERT(db->db_hash_next == NULL); 1800 ASSERT(db->db_blkptr == NULL); 1801 ASSERT(db->db_data_pending == NULL); 1802 1803 kmem_cache_free(dbuf_cache, db); 1804 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1805 } 1806 1807 void 1808 dbuf_prefetch(dnode_t *dn, uint64_t blkid) 1809 { 1810 dmu_buf_impl_t *db = NULL; 1811 blkptr_t *bp = NULL; 1812 1813 ASSERT(blkid != DMU_BONUS_BLKID); 1814 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1815 1816 if (dnode_block_freed(dn, blkid)) 1817 return; 1818 1819 /* dbuf_find() returns with db_mtx held */ 1820 if (db = dbuf_find(dn, 0, blkid)) { 1821 /* 1822 * This dbuf is already in the cache. We assume that 1823 * it is already CACHED, or else about to be either 1824 * read or filled. 1825 */ 1826 mutex_exit(&db->db_mtx); 1827 return; 1828 } 1829 1830 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) { 1831 if (bp && !BP_IS_HOLE(bp)) { 1832 int priority = dn->dn_type == DMU_OT_DDT_ZAP ? 1833 ZIO_PRIORITY_DDT_PREFETCH : ZIO_PRIORITY_ASYNC_READ; 1834 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; 1835 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH; 1836 zbookmark_t zb; 1837 1838 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET, 1839 dn->dn_object, 0, blkid); 1840 1841 (void) arc_read(NULL, dn->dn_objset->os_spa, 1842 bp, NULL, NULL, priority, 1843 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 1844 &aflags, &zb); 1845 } 1846 if (db) 1847 dbuf_rele(db, NULL); 1848 } 1849 } 1850 1851 /* 1852 * Returns with db_holds incremented, and db_mtx not held. 1853 * Note: dn_struct_rwlock must be held. 1854 */ 1855 int 1856 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse, 1857 void *tag, dmu_buf_impl_t **dbp) 1858 { 1859 dmu_buf_impl_t *db, *parent = NULL; 1860 1861 ASSERT(blkid != DMU_BONUS_BLKID); 1862 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1863 ASSERT3U(dn->dn_nlevels, >, level); 1864 1865 *dbp = NULL; 1866 top: 1867 /* dbuf_find() returns with db_mtx held */ 1868 db = dbuf_find(dn, level, blkid); 1869 1870 if (db == NULL) { 1871 blkptr_t *bp = NULL; 1872 int err; 1873 1874 ASSERT3P(parent, ==, NULL); 1875 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp); 1876 if (fail_sparse) { 1877 if (err == 0 && bp && BP_IS_HOLE(bp)) 1878 err = SET_ERROR(ENOENT); 1879 if (err) { 1880 if (parent) 1881 dbuf_rele(parent, NULL); 1882 return (err); 1883 } 1884 } 1885 if (err && err != ENOENT) 1886 return (err); 1887 db = dbuf_create(dn, level, blkid, parent, bp); 1888 } 1889 1890 if (db->db_buf && refcount_is_zero(&db->db_holds)) { 1891 arc_buf_add_ref(db->db_buf, db); 1892 if (db->db_buf->b_data == NULL) { 1893 dbuf_clear(db); 1894 if (parent) { 1895 dbuf_rele(parent, NULL); 1896 parent = NULL; 1897 } 1898 goto top; 1899 } 1900 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data); 1901 } 1902 1903 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf)); 1904 1905 /* 1906 * If this buffer is currently syncing out, and we are are 1907 * still referencing it from db_data, we need to make a copy 1908 * of it in case we decide we want to dirty it again in this txg. 1909 */ 1910 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1911 dn->dn_object != DMU_META_DNODE_OBJECT && 1912 db->db_state == DB_CACHED && db->db_data_pending) { 1913 dbuf_dirty_record_t *dr = db->db_data_pending; 1914 1915 if (dr->dt.dl.dr_data == db->db_buf) { 1916 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 1917 1918 dbuf_set_data(db, 1919 arc_buf_alloc(dn->dn_objset->os_spa, 1920 db->db.db_size, db, type)); 1921 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data, 1922 db->db.db_size); 1923 } 1924 } 1925 1926 (void) refcount_add(&db->db_holds, tag); 1927 dbuf_update_data(db); 1928 DBUF_VERIFY(db); 1929 mutex_exit(&db->db_mtx); 1930 1931 /* NOTE: we can't rele the parent until after we drop the db_mtx */ 1932 if (parent) 1933 dbuf_rele(parent, NULL); 1934 1935 ASSERT3P(DB_DNODE(db), ==, dn); 1936 ASSERT3U(db->db_blkid, ==, blkid); 1937 ASSERT3U(db->db_level, ==, level); 1938 *dbp = db; 1939 1940 return (0); 1941 } 1942 1943 dmu_buf_impl_t * 1944 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag) 1945 { 1946 dmu_buf_impl_t *db; 1947 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db); 1948 return (err ? NULL : db); 1949 } 1950 1951 dmu_buf_impl_t * 1952 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag) 1953 { 1954 dmu_buf_impl_t *db; 1955 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db); 1956 return (err ? NULL : db); 1957 } 1958 1959 void 1960 dbuf_create_bonus(dnode_t *dn) 1961 { 1962 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 1963 1964 ASSERT(dn->dn_bonus == NULL); 1965 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL); 1966 } 1967 1968 int 1969 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx) 1970 { 1971 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1972 dnode_t *dn; 1973 1974 if (db->db_blkid != DMU_SPILL_BLKID) 1975 return (SET_ERROR(ENOTSUP)); 1976 if (blksz == 0) 1977 blksz = SPA_MINBLOCKSIZE; 1978 if (blksz > SPA_MAXBLOCKSIZE) 1979 blksz = SPA_MAXBLOCKSIZE; 1980 else 1981 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE); 1982 1983 DB_DNODE_ENTER(db); 1984 dn = DB_DNODE(db); 1985 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 1986 dbuf_new_size(db, blksz, tx); 1987 rw_exit(&dn->dn_struct_rwlock); 1988 DB_DNODE_EXIT(db); 1989 1990 return (0); 1991 } 1992 1993 void 1994 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx) 1995 { 1996 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx); 1997 } 1998 1999 #pragma weak dmu_buf_add_ref = dbuf_add_ref 2000 void 2001 dbuf_add_ref(dmu_buf_impl_t *db, void *tag) 2002 { 2003 int64_t holds = refcount_add(&db->db_holds, tag); 2004 ASSERT(holds > 1); 2005 } 2006 2007 /* 2008 * If you call dbuf_rele() you had better not be referencing the dnode handle 2009 * unless you have some other direct or indirect hold on the dnode. (An indirect 2010 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.) 2011 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the 2012 * dnode's parent dbuf evicting its dnode handles. 2013 */ 2014 #pragma weak dmu_buf_rele = dbuf_rele 2015 void 2016 dbuf_rele(dmu_buf_impl_t *db, void *tag) 2017 { 2018 mutex_enter(&db->db_mtx); 2019 dbuf_rele_and_unlock(db, tag); 2020 } 2021 2022 /* 2023 * dbuf_rele() for an already-locked dbuf. This is necessary to allow 2024 * db_dirtycnt and db_holds to be updated atomically. 2025 */ 2026 void 2027 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) 2028 { 2029 int64_t holds; 2030 2031 ASSERT(MUTEX_HELD(&db->db_mtx)); 2032 DBUF_VERIFY(db); 2033 2034 /* 2035 * Remove the reference to the dbuf before removing its hold on the 2036 * dnode so we can guarantee in dnode_move() that a referenced bonus 2037 * buffer has a corresponding dnode hold. 2038 */ 2039 holds = refcount_remove(&db->db_holds, tag); 2040 ASSERT(holds >= 0); 2041 2042 /* 2043 * We can't freeze indirects if there is a possibility that they 2044 * may be modified in the current syncing context. 2045 */ 2046 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0)) 2047 arc_buf_freeze(db->db_buf); 2048 2049 if (holds == db->db_dirtycnt && 2050 db->db_level == 0 && db->db_immediate_evict) 2051 dbuf_evict_user(db); 2052 2053 if (holds == 0) { 2054 if (db->db_blkid == DMU_BONUS_BLKID) { 2055 mutex_exit(&db->db_mtx); 2056 2057 /* 2058 * If the dnode moves here, we cannot cross this barrier 2059 * until the move completes. 2060 */ 2061 DB_DNODE_ENTER(db); 2062 (void) atomic_dec_32_nv(&DB_DNODE(db)->dn_dbufs_count); 2063 DB_DNODE_EXIT(db); 2064 /* 2065 * The bonus buffer's dnode hold is no longer discounted 2066 * in dnode_move(). The dnode cannot move until after 2067 * the dnode_rele(). 2068 */ 2069 dnode_rele(DB_DNODE(db), db); 2070 } else if (db->db_buf == NULL) { 2071 /* 2072 * This is a special case: we never associated this 2073 * dbuf with any data allocated from the ARC. 2074 */ 2075 ASSERT(db->db_state == DB_UNCACHED || 2076 db->db_state == DB_NOFILL); 2077 dbuf_evict(db); 2078 } else if (arc_released(db->db_buf)) { 2079 arc_buf_t *buf = db->db_buf; 2080 /* 2081 * This dbuf has anonymous data associated with it. 2082 */ 2083 dbuf_set_data(db, NULL); 2084 VERIFY(arc_buf_remove_ref(buf, db)); 2085 dbuf_evict(db); 2086 } else { 2087 VERIFY(!arc_buf_remove_ref(db->db_buf, db)); 2088 2089 /* 2090 * A dbuf will be eligible for eviction if either the 2091 * 'primarycache' property is set or a duplicate 2092 * copy of this buffer is already cached in the arc. 2093 * 2094 * In the case of the 'primarycache' a buffer 2095 * is considered for eviction if it matches the 2096 * criteria set in the property. 2097 * 2098 * To decide if our buffer is considered a 2099 * duplicate, we must call into the arc to determine 2100 * if multiple buffers are referencing the same 2101 * block on-disk. If so, then we simply evict 2102 * ourselves. 2103 */ 2104 if (!DBUF_IS_CACHEABLE(db) || 2105 arc_buf_eviction_needed(db->db_buf)) 2106 dbuf_clear(db); 2107 else 2108 mutex_exit(&db->db_mtx); 2109 } 2110 } else { 2111 mutex_exit(&db->db_mtx); 2112 } 2113 } 2114 2115 #pragma weak dmu_buf_refcount = dbuf_refcount 2116 uint64_t 2117 dbuf_refcount(dmu_buf_impl_t *db) 2118 { 2119 return (refcount_count(&db->db_holds)); 2120 } 2121 2122 void * 2123 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr, 2124 dmu_buf_evict_func_t *evict_func) 2125 { 2126 return (dmu_buf_update_user(db_fake, NULL, user_ptr, 2127 user_data_ptr_ptr, evict_func)); 2128 } 2129 2130 void * 2131 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr, 2132 dmu_buf_evict_func_t *evict_func) 2133 { 2134 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2135 2136 db->db_immediate_evict = TRUE; 2137 return (dmu_buf_update_user(db_fake, NULL, user_ptr, 2138 user_data_ptr_ptr, evict_func)); 2139 } 2140 2141 void * 2142 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr, 2143 void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func) 2144 { 2145 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2146 ASSERT(db->db_level == 0); 2147 2148 ASSERT((user_ptr == NULL) == (evict_func == NULL)); 2149 2150 mutex_enter(&db->db_mtx); 2151 2152 if (db->db_user_ptr == old_user_ptr) { 2153 db->db_user_ptr = user_ptr; 2154 db->db_user_data_ptr_ptr = user_data_ptr_ptr; 2155 db->db_evict_func = evict_func; 2156 2157 dbuf_update_data(db); 2158 } else { 2159 old_user_ptr = db->db_user_ptr; 2160 } 2161 2162 mutex_exit(&db->db_mtx); 2163 return (old_user_ptr); 2164 } 2165 2166 void * 2167 dmu_buf_get_user(dmu_buf_t *db_fake) 2168 { 2169 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2170 ASSERT(!refcount_is_zero(&db->db_holds)); 2171 2172 return (db->db_user_ptr); 2173 } 2174 2175 boolean_t 2176 dmu_buf_freeable(dmu_buf_t *dbuf) 2177 { 2178 boolean_t res = B_FALSE; 2179 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 2180 2181 if (db->db_blkptr) 2182 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset, 2183 db->db_blkptr, db->db_blkptr->blk_birth); 2184 2185 return (res); 2186 } 2187 2188 blkptr_t * 2189 dmu_buf_get_blkptr(dmu_buf_t *db) 2190 { 2191 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; 2192 return (dbi->db_blkptr); 2193 } 2194 2195 static void 2196 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db) 2197 { 2198 /* ASSERT(dmu_tx_is_syncing(tx) */ 2199 ASSERT(MUTEX_HELD(&db->db_mtx)); 2200 2201 if (db->db_blkptr != NULL) 2202 return; 2203 2204 if (db->db_blkid == DMU_SPILL_BLKID) { 2205 db->db_blkptr = &dn->dn_phys->dn_spill; 2206 BP_ZERO(db->db_blkptr); 2207 return; 2208 } 2209 if (db->db_level == dn->dn_phys->dn_nlevels-1) { 2210 /* 2211 * This buffer was allocated at a time when there was 2212 * no available blkptrs from the dnode, or it was 2213 * inappropriate to hook it in (i.e., nlevels mis-match). 2214 */ 2215 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr); 2216 ASSERT(db->db_parent == NULL); 2217 db->db_parent = dn->dn_dbuf; 2218 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid]; 2219 DBUF_VERIFY(db); 2220 } else { 2221 dmu_buf_impl_t *parent = db->db_parent; 2222 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2223 2224 ASSERT(dn->dn_phys->dn_nlevels > 1); 2225 if (parent == NULL) { 2226 mutex_exit(&db->db_mtx); 2227 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2228 (void) dbuf_hold_impl(dn, db->db_level+1, 2229 db->db_blkid >> epbs, FALSE, db, &parent); 2230 rw_exit(&dn->dn_struct_rwlock); 2231 mutex_enter(&db->db_mtx); 2232 db->db_parent = parent; 2233 } 2234 db->db_blkptr = (blkptr_t *)parent->db.db_data + 2235 (db->db_blkid & ((1ULL << epbs) - 1)); 2236 DBUF_VERIFY(db); 2237 } 2238 } 2239 2240 static void 2241 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2242 { 2243 dmu_buf_impl_t *db = dr->dr_dbuf; 2244 dnode_t *dn; 2245 zio_t *zio; 2246 2247 ASSERT(dmu_tx_is_syncing(tx)); 2248 2249 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2250 2251 mutex_enter(&db->db_mtx); 2252 2253 ASSERT(db->db_level > 0); 2254 DBUF_VERIFY(db); 2255 2256 /* Read the block if it hasn't been read yet. */ 2257 if (db->db_buf == NULL) { 2258 mutex_exit(&db->db_mtx); 2259 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); 2260 mutex_enter(&db->db_mtx); 2261 } 2262 ASSERT3U(db->db_state, ==, DB_CACHED); 2263 ASSERT(db->db_buf != NULL); 2264 2265 DB_DNODE_ENTER(db); 2266 dn = DB_DNODE(db); 2267 /* Indirect block size must match what the dnode thinks it is. */ 2268 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2269 dbuf_check_blkptr(dn, db); 2270 DB_DNODE_EXIT(db); 2271 2272 /* Provide the pending dirty record to child dbufs */ 2273 db->db_data_pending = dr; 2274 2275 mutex_exit(&db->db_mtx); 2276 dbuf_write(dr, db->db_buf, tx); 2277 2278 zio = dr->dr_zio; 2279 mutex_enter(&dr->dt.di.dr_mtx); 2280 dbuf_sync_list(&dr->dt.di.dr_children, tx); 2281 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2282 mutex_exit(&dr->dt.di.dr_mtx); 2283 zio_nowait(zio); 2284 } 2285 2286 static void 2287 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2288 { 2289 arc_buf_t **datap = &dr->dt.dl.dr_data; 2290 dmu_buf_impl_t *db = dr->dr_dbuf; 2291 dnode_t *dn; 2292 objset_t *os; 2293 uint64_t txg = tx->tx_txg; 2294 2295 ASSERT(dmu_tx_is_syncing(tx)); 2296 2297 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2298 2299 mutex_enter(&db->db_mtx); 2300 /* 2301 * To be synced, we must be dirtied. But we 2302 * might have been freed after the dirty. 2303 */ 2304 if (db->db_state == DB_UNCACHED) { 2305 /* This buffer has been freed since it was dirtied */ 2306 ASSERT(db->db.db_data == NULL); 2307 } else if (db->db_state == DB_FILL) { 2308 /* This buffer was freed and is now being re-filled */ 2309 ASSERT(db->db.db_data != dr->dt.dl.dr_data); 2310 } else { 2311 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); 2312 } 2313 DBUF_VERIFY(db); 2314 2315 DB_DNODE_ENTER(db); 2316 dn = DB_DNODE(db); 2317 2318 if (db->db_blkid == DMU_SPILL_BLKID) { 2319 mutex_enter(&dn->dn_mtx); 2320 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR; 2321 mutex_exit(&dn->dn_mtx); 2322 } 2323 2324 /* 2325 * If this is a bonus buffer, simply copy the bonus data into the 2326 * dnode. It will be written out when the dnode is synced (and it 2327 * will be synced, since it must have been dirty for dbuf_sync to 2328 * be called). 2329 */ 2330 if (db->db_blkid == DMU_BONUS_BLKID) { 2331 dbuf_dirty_record_t **drp; 2332 2333 ASSERT(*datap != NULL); 2334 ASSERT0(db->db_level); 2335 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN); 2336 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen); 2337 DB_DNODE_EXIT(db); 2338 2339 if (*datap != db->db.db_data) { 2340 zio_buf_free(*datap, DN_MAX_BONUSLEN); 2341 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 2342 } 2343 db->db_data_pending = NULL; 2344 drp = &db->db_last_dirty; 2345 while (*drp != dr) 2346 drp = &(*drp)->dr_next; 2347 ASSERT(dr->dr_next == NULL); 2348 ASSERT(dr->dr_dbuf == db); 2349 *drp = dr->dr_next; 2350 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2351 ASSERT(db->db_dirtycnt > 0); 2352 db->db_dirtycnt -= 1; 2353 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2354 return; 2355 } 2356 2357 os = dn->dn_objset; 2358 2359 /* 2360 * This function may have dropped the db_mtx lock allowing a dmu_sync 2361 * operation to sneak in. As a result, we need to ensure that we 2362 * don't check the dr_override_state until we have returned from 2363 * dbuf_check_blkptr. 2364 */ 2365 dbuf_check_blkptr(dn, db); 2366 2367 /* 2368 * If this buffer is in the middle of an immediate write, 2369 * wait for the synchronous IO to complete. 2370 */ 2371 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) { 2372 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); 2373 cv_wait(&db->db_changed, &db->db_mtx); 2374 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN); 2375 } 2376 2377 if (db->db_state != DB_NOFILL && 2378 dn->dn_object != DMU_META_DNODE_OBJECT && 2379 refcount_count(&db->db_holds) > 1 && 2380 dr->dt.dl.dr_override_state != DR_OVERRIDDEN && 2381 *datap == db->db_buf) { 2382 /* 2383 * If this buffer is currently "in use" (i.e., there 2384 * are active holds and db_data still references it), 2385 * then make a copy before we start the write so that 2386 * any modifications from the open txg will not leak 2387 * into this write. 2388 * 2389 * NOTE: this copy does not need to be made for 2390 * objects only modified in the syncing context (e.g. 2391 * DNONE_DNODE blocks). 2392 */ 2393 int blksz = arc_buf_size(*datap); 2394 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2395 *datap = arc_buf_alloc(os->os_spa, blksz, db, type); 2396 bcopy(db->db.db_data, (*datap)->b_data, blksz); 2397 } 2398 db->db_data_pending = dr; 2399 2400 mutex_exit(&db->db_mtx); 2401 2402 dbuf_write(dr, *datap, tx); 2403 2404 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2405 if (dn->dn_object == DMU_META_DNODE_OBJECT) { 2406 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr); 2407 DB_DNODE_EXIT(db); 2408 } else { 2409 /* 2410 * Although zio_nowait() does not "wait for an IO", it does 2411 * initiate the IO. If this is an empty write it seems plausible 2412 * that the IO could actually be completed before the nowait 2413 * returns. We need to DB_DNODE_EXIT() first in case 2414 * zio_nowait() invalidates the dbuf. 2415 */ 2416 DB_DNODE_EXIT(db); 2417 zio_nowait(dr->dr_zio); 2418 } 2419 } 2420 2421 void 2422 dbuf_sync_list(list_t *list, dmu_tx_t *tx) 2423 { 2424 dbuf_dirty_record_t *dr; 2425 2426 while (dr = list_head(list)) { 2427 if (dr->dr_zio != NULL) { 2428 /* 2429 * If we find an already initialized zio then we 2430 * are processing the meta-dnode, and we have finished. 2431 * The dbufs for all dnodes are put back on the list 2432 * during processing, so that we can zio_wait() 2433 * these IOs after initiating all child IOs. 2434 */ 2435 ASSERT3U(dr->dr_dbuf->db.db_object, ==, 2436 DMU_META_DNODE_OBJECT); 2437 break; 2438 } 2439 list_remove(list, dr); 2440 if (dr->dr_dbuf->db_level > 0) 2441 dbuf_sync_indirect(dr, tx); 2442 else 2443 dbuf_sync_leaf(dr, tx); 2444 } 2445 } 2446 2447 /* ARGSUSED */ 2448 static void 2449 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb) 2450 { 2451 dmu_buf_impl_t *db = vdb; 2452 dnode_t *dn; 2453 blkptr_t *bp = zio->io_bp; 2454 blkptr_t *bp_orig = &zio->io_bp_orig; 2455 spa_t *spa = zio->io_spa; 2456 int64_t delta; 2457 uint64_t fill = 0; 2458 int i; 2459 2460 ASSERT(db->db_blkptr == bp); 2461 2462 DB_DNODE_ENTER(db); 2463 dn = DB_DNODE(db); 2464 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig); 2465 dnode_diduse_space(dn, delta - zio->io_prev_space_delta); 2466 zio->io_prev_space_delta = delta; 2467 2468 if (BP_IS_HOLE(bp)) { 2469 ASSERT(bp->blk_fill == 0); 2470 DB_DNODE_EXIT(db); 2471 return; 2472 } 2473 2474 ASSERT((db->db_blkid != DMU_SPILL_BLKID && 2475 BP_GET_TYPE(bp) == dn->dn_type) || 2476 (db->db_blkid == DMU_SPILL_BLKID && 2477 BP_GET_TYPE(bp) == dn->dn_bonustype)); 2478 ASSERT(BP_GET_LEVEL(bp) == db->db_level); 2479 2480 mutex_enter(&db->db_mtx); 2481 2482 #ifdef ZFS_DEBUG 2483 if (db->db_blkid == DMU_SPILL_BLKID) { 2484 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2485 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2486 db->db_blkptr == &dn->dn_phys->dn_spill); 2487 } 2488 #endif 2489 2490 if (db->db_level == 0) { 2491 mutex_enter(&dn->dn_mtx); 2492 if (db->db_blkid > dn->dn_phys->dn_maxblkid && 2493 db->db_blkid != DMU_SPILL_BLKID) 2494 dn->dn_phys->dn_maxblkid = db->db_blkid; 2495 mutex_exit(&dn->dn_mtx); 2496 2497 if (dn->dn_type == DMU_OT_DNODE) { 2498 dnode_phys_t *dnp = db->db.db_data; 2499 for (i = db->db.db_size >> DNODE_SHIFT; i > 0; 2500 i--, dnp++) { 2501 if (dnp->dn_type != DMU_OT_NONE) 2502 fill++; 2503 } 2504 } else { 2505 fill = 1; 2506 } 2507 } else { 2508 blkptr_t *ibp = db->db.db_data; 2509 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2510 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) { 2511 if (BP_IS_HOLE(ibp)) 2512 continue; 2513 fill += ibp->blk_fill; 2514 } 2515 } 2516 DB_DNODE_EXIT(db); 2517 2518 bp->blk_fill = fill; 2519 2520 mutex_exit(&db->db_mtx); 2521 } 2522 2523 /* ARGSUSED */ 2524 static void 2525 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb) 2526 { 2527 dmu_buf_impl_t *db = vdb; 2528 blkptr_t *bp = zio->io_bp; 2529 blkptr_t *bp_orig = &zio->io_bp_orig; 2530 uint64_t txg = zio->io_txg; 2531 dbuf_dirty_record_t **drp, *dr; 2532 2533 ASSERT0(zio->io_error); 2534 ASSERT(db->db_blkptr == bp); 2535 2536 /* 2537 * For nopwrites and rewrites we ensure that the bp matches our 2538 * original and bypass all the accounting. 2539 */ 2540 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) { 2541 ASSERT(BP_EQUAL(bp, bp_orig)); 2542 } else { 2543 objset_t *os; 2544 dsl_dataset_t *ds; 2545 dmu_tx_t *tx; 2546 2547 DB_GET_OBJSET(&os, db); 2548 ds = os->os_dsl_dataset; 2549 tx = os->os_synctx; 2550 2551 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE); 2552 dsl_dataset_block_born(ds, bp, tx); 2553 } 2554 2555 mutex_enter(&db->db_mtx); 2556 2557 DBUF_VERIFY(db); 2558 2559 drp = &db->db_last_dirty; 2560 while ((dr = *drp) != db->db_data_pending) 2561 drp = &dr->dr_next; 2562 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2563 ASSERT(dr->dr_txg == txg); 2564 ASSERT(dr->dr_dbuf == db); 2565 ASSERT(dr->dr_next == NULL); 2566 *drp = dr->dr_next; 2567 2568 #ifdef ZFS_DEBUG 2569 if (db->db_blkid == DMU_SPILL_BLKID) { 2570 dnode_t *dn; 2571 2572 DB_DNODE_ENTER(db); 2573 dn = DB_DNODE(db); 2574 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2575 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2576 db->db_blkptr == &dn->dn_phys->dn_spill); 2577 DB_DNODE_EXIT(db); 2578 } 2579 #endif 2580 2581 if (db->db_level == 0) { 2582 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 2583 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN); 2584 if (db->db_state != DB_NOFILL) { 2585 if (dr->dt.dl.dr_data != db->db_buf) 2586 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 2587 db)); 2588 else if (!arc_released(db->db_buf)) 2589 arc_set_callback(db->db_buf, dbuf_do_evict, db); 2590 } 2591 } else { 2592 dnode_t *dn; 2593 2594 DB_DNODE_ENTER(db); 2595 dn = DB_DNODE(db); 2596 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2597 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2598 if (!BP_IS_HOLE(db->db_blkptr)) { 2599 int epbs = 2600 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2601 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, 2602 db->db.db_size); 2603 ASSERT3U(dn->dn_phys->dn_maxblkid 2604 >> (db->db_level * epbs), >=, db->db_blkid); 2605 arc_set_callback(db->db_buf, dbuf_do_evict, db); 2606 } 2607 DB_DNODE_EXIT(db); 2608 mutex_destroy(&dr->dt.di.dr_mtx); 2609 list_destroy(&dr->dt.di.dr_children); 2610 } 2611 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2612 2613 cv_broadcast(&db->db_changed); 2614 ASSERT(db->db_dirtycnt > 0); 2615 db->db_dirtycnt -= 1; 2616 db->db_data_pending = NULL; 2617 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2618 } 2619 2620 static void 2621 dbuf_write_nofill_ready(zio_t *zio) 2622 { 2623 dbuf_write_ready(zio, NULL, zio->io_private); 2624 } 2625 2626 static void 2627 dbuf_write_nofill_done(zio_t *zio) 2628 { 2629 dbuf_write_done(zio, NULL, zio->io_private); 2630 } 2631 2632 static void 2633 dbuf_write_override_ready(zio_t *zio) 2634 { 2635 dbuf_dirty_record_t *dr = zio->io_private; 2636 dmu_buf_impl_t *db = dr->dr_dbuf; 2637 2638 dbuf_write_ready(zio, NULL, db); 2639 } 2640 2641 static void 2642 dbuf_write_override_done(zio_t *zio) 2643 { 2644 dbuf_dirty_record_t *dr = zio->io_private; 2645 dmu_buf_impl_t *db = dr->dr_dbuf; 2646 blkptr_t *obp = &dr->dt.dl.dr_overridden_by; 2647 2648 mutex_enter(&db->db_mtx); 2649 if (!BP_EQUAL(zio->io_bp, obp)) { 2650 if (!BP_IS_HOLE(obp)) 2651 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp); 2652 arc_release(dr->dt.dl.dr_data, db); 2653 } 2654 mutex_exit(&db->db_mtx); 2655 2656 dbuf_write_done(zio, NULL, db); 2657 } 2658 2659 /* Issue I/O to commit a dirty buffer to disk. */ 2660 static void 2661 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) 2662 { 2663 dmu_buf_impl_t *db = dr->dr_dbuf; 2664 dnode_t *dn; 2665 objset_t *os; 2666 dmu_buf_impl_t *parent = db->db_parent; 2667 uint64_t txg = tx->tx_txg; 2668 zbookmark_t zb; 2669 zio_prop_t zp; 2670 zio_t *zio; 2671 int wp_flag = 0; 2672 2673 DB_DNODE_ENTER(db); 2674 dn = DB_DNODE(db); 2675 os = dn->dn_objset; 2676 2677 if (db->db_state != DB_NOFILL) { 2678 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) { 2679 /* 2680 * Private object buffers are released here rather 2681 * than in dbuf_dirty() since they are only modified 2682 * in the syncing context and we don't want the 2683 * overhead of making multiple copies of the data. 2684 */ 2685 if (BP_IS_HOLE(db->db_blkptr)) { 2686 arc_buf_thaw(data); 2687 } else { 2688 dbuf_release_bp(db); 2689 } 2690 } 2691 } 2692 2693 if (parent != dn->dn_dbuf) { 2694 /* Our parent is an indirect block. */ 2695 /* We have a dirty parent that has been scheduled for write. */ 2696 ASSERT(parent && parent->db_data_pending); 2697 /* Our parent's buffer is one level closer to the dnode. */ 2698 ASSERT(db->db_level == parent->db_level-1); 2699 /* 2700 * We're about to modify our parent's db_data by modifying 2701 * our block pointer, so the parent must be released. 2702 */ 2703 ASSERT(arc_released(parent->db_buf)); 2704 zio = parent->db_data_pending->dr_zio; 2705 } else { 2706 /* Our parent is the dnode itself. */ 2707 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && 2708 db->db_blkid != DMU_SPILL_BLKID) || 2709 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); 2710 if (db->db_blkid != DMU_SPILL_BLKID) 2711 ASSERT3P(db->db_blkptr, ==, 2712 &dn->dn_phys->dn_blkptr[db->db_blkid]); 2713 zio = dn->dn_zio; 2714 } 2715 2716 ASSERT(db->db_level == 0 || data == db->db_buf); 2717 ASSERT3U(db->db_blkptr->blk_birth, <=, txg); 2718 ASSERT(zio); 2719 2720 SET_BOOKMARK(&zb, os->os_dsl_dataset ? 2721 os->os_dsl_dataset->ds_object : DMU_META_OBJSET, 2722 db->db.db_object, db->db_level, db->db_blkid); 2723 2724 if (db->db_blkid == DMU_SPILL_BLKID) 2725 wp_flag = WP_SPILL; 2726 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0; 2727 2728 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp); 2729 DB_DNODE_EXIT(db); 2730 2731 if (db->db_level == 0 && dr->dt.dl.dr_override_state == DR_OVERRIDDEN) { 2732 ASSERT(db->db_state != DB_NOFILL); 2733 dr->dr_zio = zio_write(zio, os->os_spa, txg, 2734 db->db_blkptr, data->b_data, arc_buf_size(data), &zp, 2735 dbuf_write_override_ready, dbuf_write_override_done, dr, 2736 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 2737 mutex_enter(&db->db_mtx); 2738 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 2739 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by, 2740 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite); 2741 mutex_exit(&db->db_mtx); 2742 } else if (db->db_state == DB_NOFILL) { 2743 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF); 2744 dr->dr_zio = zio_write(zio, os->os_spa, txg, 2745 db->db_blkptr, NULL, db->db.db_size, &zp, 2746 dbuf_write_nofill_ready, dbuf_write_nofill_done, db, 2747 ZIO_PRIORITY_ASYNC_WRITE, 2748 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb); 2749 } else { 2750 ASSERT(arc_released(data)); 2751 dr->dr_zio = arc_write(zio, os->os_spa, txg, 2752 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), 2753 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready, 2754 dbuf_write_done, db, ZIO_PRIORITY_ASYNC_WRITE, 2755 ZIO_FLAG_MUSTSUCCEED, &zb); 2756 } 2757 } 2758