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 */ 24 25 #include <sys/zfs_context.h> 26 #include <sys/dmu.h> 27 #include <sys/dmu_impl.h> 28 #include <sys/dbuf.h> 29 #include <sys/dmu_objset.h> 30 #include <sys/dsl_dataset.h> 31 #include <sys/dsl_dir.h> 32 #include <sys/dmu_tx.h> 33 #include <sys/spa.h> 34 #include <sys/zio.h> 35 #include <sys/dmu_zfetch.h> 36 #include <sys/sa.h> 37 #include <sys/sa_impl.h> 38 39 static void dbuf_destroy(dmu_buf_impl_t *db); 40 static int dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 41 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx); 42 43 /* 44 * Global data structures and functions for the dbuf cache. 45 */ 46 static kmem_cache_t *dbuf_cache; 47 48 /* ARGSUSED */ 49 static int 50 dbuf_cons(void *vdb, void *unused, int kmflag) 51 { 52 dmu_buf_impl_t *db = vdb; 53 bzero(db, sizeof (dmu_buf_impl_t)); 54 55 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL); 56 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL); 57 refcount_create(&db->db_holds); 58 return (0); 59 } 60 61 /* ARGSUSED */ 62 static void 63 dbuf_dest(void *vdb, void *unused) 64 { 65 dmu_buf_impl_t *db = vdb; 66 mutex_destroy(&db->db_mtx); 67 cv_destroy(&db->db_changed); 68 refcount_destroy(&db->db_holds); 69 } 70 71 /* 72 * dbuf hash table routines 73 */ 74 static dbuf_hash_table_t dbuf_hash_table; 75 76 static uint64_t dbuf_hash_count; 77 78 static uint64_t 79 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid) 80 { 81 uintptr_t osv = (uintptr_t)os; 82 uint64_t crc = -1ULL; 83 84 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); 85 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF]; 86 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF]; 87 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF]; 88 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF]; 89 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF]; 90 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF]; 91 92 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16); 93 94 return (crc); 95 } 96 97 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid); 98 99 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \ 100 ((dbuf)->db.db_object == (obj) && \ 101 (dbuf)->db_objset == (os) && \ 102 (dbuf)->db_level == (level) && \ 103 (dbuf)->db_blkid == (blkid)) 104 105 dmu_buf_impl_t * 106 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid) 107 { 108 dbuf_hash_table_t *h = &dbuf_hash_table; 109 objset_t *os = dn->dn_objset; 110 uint64_t obj = dn->dn_object; 111 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 112 uint64_t idx = hv & h->hash_table_mask; 113 dmu_buf_impl_t *db; 114 115 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 116 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) { 117 if (DBUF_EQUAL(db, os, obj, level, blkid)) { 118 mutex_enter(&db->db_mtx); 119 if (db->db_state != DB_EVICTING) { 120 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 121 return (db); 122 } 123 mutex_exit(&db->db_mtx); 124 } 125 } 126 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 127 return (NULL); 128 } 129 130 /* 131 * Insert an entry into the hash table. If there is already an element 132 * equal to elem in the hash table, then the already existing element 133 * will be returned and the new element will not be inserted. 134 * Otherwise returns NULL. 135 */ 136 static dmu_buf_impl_t * 137 dbuf_hash_insert(dmu_buf_impl_t *db) 138 { 139 dbuf_hash_table_t *h = &dbuf_hash_table; 140 objset_t *os = db->db_objset; 141 uint64_t obj = db->db.db_object; 142 int level = db->db_level; 143 uint64_t blkid = db->db_blkid; 144 uint64_t hv = DBUF_HASH(os, obj, level, blkid); 145 uint64_t idx = hv & h->hash_table_mask; 146 dmu_buf_impl_t *dbf; 147 148 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 149 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) { 150 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) { 151 mutex_enter(&dbf->db_mtx); 152 if (dbf->db_state != DB_EVICTING) { 153 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 154 return (dbf); 155 } 156 mutex_exit(&dbf->db_mtx); 157 } 158 } 159 160 mutex_enter(&db->db_mtx); 161 db->db_hash_next = h->hash_table[idx]; 162 h->hash_table[idx] = db; 163 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 164 atomic_add_64(&dbuf_hash_count, 1); 165 166 return (NULL); 167 } 168 169 /* 170 * Remove an entry from the hash table. This operation will 171 * fail if there are any existing holds on the db. 172 */ 173 static void 174 dbuf_hash_remove(dmu_buf_impl_t *db) 175 { 176 dbuf_hash_table_t *h = &dbuf_hash_table; 177 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object, 178 db->db_level, db->db_blkid); 179 uint64_t idx = hv & h->hash_table_mask; 180 dmu_buf_impl_t *dbf, **dbp; 181 182 /* 183 * We musn't hold db_mtx to maintin lock ordering: 184 * DBUF_HASH_MUTEX > db_mtx. 185 */ 186 ASSERT(refcount_is_zero(&db->db_holds)); 187 ASSERT(db->db_state == DB_EVICTING); 188 ASSERT(!MUTEX_HELD(&db->db_mtx)); 189 190 mutex_enter(DBUF_HASH_MUTEX(h, idx)); 191 dbp = &h->hash_table[idx]; 192 while ((dbf = *dbp) != db) { 193 dbp = &dbf->db_hash_next; 194 ASSERT(dbf != NULL); 195 } 196 *dbp = db->db_hash_next; 197 db->db_hash_next = NULL; 198 mutex_exit(DBUF_HASH_MUTEX(h, idx)); 199 atomic_add_64(&dbuf_hash_count, -1); 200 } 201 202 static arc_evict_func_t dbuf_do_evict; 203 204 static void 205 dbuf_evict_user(dmu_buf_impl_t *db) 206 { 207 ASSERT(MUTEX_HELD(&db->db_mtx)); 208 209 if (db->db_level != 0 || db->db_evict_func == NULL) 210 return; 211 212 if (db->db_user_data_ptr_ptr) 213 *db->db_user_data_ptr_ptr = db->db.db_data; 214 db->db_evict_func(&db->db, db->db_user_ptr); 215 db->db_user_ptr = NULL; 216 db->db_user_data_ptr_ptr = NULL; 217 db->db_evict_func = NULL; 218 } 219 220 void 221 dbuf_evict(dmu_buf_impl_t *db) 222 { 223 ASSERT(MUTEX_HELD(&db->db_mtx)); 224 ASSERT(db->db_buf == NULL); 225 ASSERT(db->db_data_pending == NULL); 226 227 dbuf_clear(db); 228 dbuf_destroy(db); 229 } 230 231 void 232 dbuf_init(void) 233 { 234 uint64_t hsize = 1ULL << 16; 235 dbuf_hash_table_t *h = &dbuf_hash_table; 236 int i; 237 238 /* 239 * The hash table is big enough to fill all of physical memory 240 * with an average 4K block size. The table will take up 241 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers). 242 */ 243 while (hsize * 4096 < physmem * PAGESIZE) 244 hsize <<= 1; 245 246 retry: 247 h->hash_table_mask = hsize - 1; 248 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP); 249 if (h->hash_table == NULL) { 250 /* XXX - we should really return an error instead of assert */ 251 ASSERT(hsize > (1ULL << 10)); 252 hsize >>= 1; 253 goto retry; 254 } 255 256 dbuf_cache = kmem_cache_create("dmu_buf_impl_t", 257 sizeof (dmu_buf_impl_t), 258 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0); 259 260 for (i = 0; i < DBUF_MUTEXES; i++) 261 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL); 262 } 263 264 void 265 dbuf_fini(void) 266 { 267 dbuf_hash_table_t *h = &dbuf_hash_table; 268 int i; 269 270 for (i = 0; i < DBUF_MUTEXES; i++) 271 mutex_destroy(&h->hash_mutexes[i]); 272 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *)); 273 kmem_cache_destroy(dbuf_cache); 274 } 275 276 /* 277 * Other stuff. 278 */ 279 280 #ifdef ZFS_DEBUG 281 static void 282 dbuf_verify(dmu_buf_impl_t *db) 283 { 284 dnode_t *dn = db->db_dnode; 285 dbuf_dirty_record_t *dr; 286 287 ASSERT(MUTEX_HELD(&db->db_mtx)); 288 289 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY)) 290 return; 291 292 ASSERT(db->db_objset != NULL); 293 if (dn == NULL) { 294 ASSERT(db->db_parent == NULL); 295 ASSERT(db->db_blkptr == NULL); 296 } else { 297 ASSERT3U(db->db.db_object, ==, dn->dn_object); 298 ASSERT3P(db->db_objset, ==, dn->dn_objset); 299 ASSERT3U(db->db_level, <, dn->dn_nlevels); 300 ASSERT(db->db_blkid == DMU_BONUS_BLKID || db->db_blkid == 301 DMU_SPILL_BLKID || list_head(&dn->dn_dbufs)); 302 } 303 if (db->db_blkid == DMU_BONUS_BLKID) { 304 ASSERT(dn != NULL); 305 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 306 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID); 307 } else if (db->db_blkid == DMU_SPILL_BLKID) { 308 ASSERT(dn != NULL); 309 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 310 ASSERT3U(db->db.db_offset, ==, 0); 311 } else { 312 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size); 313 } 314 315 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next) 316 ASSERT(dr->dr_dbuf == db); 317 318 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next) 319 ASSERT(dr->dr_dbuf == db); 320 321 /* 322 * We can't assert that db_size matches dn_datablksz because it 323 * can be momentarily different when another thread is doing 324 * dnode_set_blksz(). 325 */ 326 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) { 327 dr = db->db_data_pending; 328 /* 329 * It should only be modified in syncing context, so 330 * make sure we only have one copy of the data. 331 */ 332 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf); 333 } 334 335 /* verify db->db_blkptr */ 336 if (db->db_blkptr) { 337 if (db->db_parent == dn->dn_dbuf) { 338 /* db is pointed to by the dnode */ 339 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */ 340 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object)) 341 ASSERT(db->db_parent == NULL); 342 else 343 ASSERT(db->db_parent != NULL); 344 if (db->db_blkid != DMU_SPILL_BLKID) 345 ASSERT3P(db->db_blkptr, ==, 346 &dn->dn_phys->dn_blkptr[db->db_blkid]); 347 } else { 348 /* db is pointed to by an indirect block */ 349 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT; 350 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1); 351 ASSERT3U(db->db_parent->db.db_object, ==, 352 db->db.db_object); 353 /* 354 * dnode_grow_indblksz() can make this fail if we don't 355 * have the struct_rwlock. XXX indblksz no longer 356 * grows. safe to do this now? 357 */ 358 if (RW_WRITE_HELD(&db->db_dnode->dn_struct_rwlock)) { 359 ASSERT3P(db->db_blkptr, ==, 360 ((blkptr_t *)db->db_parent->db.db_data + 361 db->db_blkid % epb)); 362 } 363 } 364 } 365 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) && 366 (db->db_buf == NULL || db->db_buf->b_data) && 367 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID && 368 db->db_state != DB_FILL && !dn->dn_free_txg) { 369 /* 370 * If the blkptr isn't set but they have nonzero data, 371 * it had better be dirty, otherwise we'll lose that 372 * data when we evict this buffer. 373 */ 374 if (db->db_dirtycnt == 0) { 375 uint64_t *buf = db->db.db_data; 376 int i; 377 378 for (i = 0; i < db->db.db_size >> 3; i++) { 379 ASSERT(buf[i] == 0); 380 } 381 } 382 } 383 } 384 #endif 385 386 static void 387 dbuf_update_data(dmu_buf_impl_t *db) 388 { 389 ASSERT(MUTEX_HELD(&db->db_mtx)); 390 if (db->db_level == 0 && db->db_user_data_ptr_ptr) { 391 ASSERT(!refcount_is_zero(&db->db_holds)); 392 *db->db_user_data_ptr_ptr = db->db.db_data; 393 } 394 } 395 396 static void 397 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf) 398 { 399 ASSERT(MUTEX_HELD(&db->db_mtx)); 400 ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf)); 401 db->db_buf = buf; 402 if (buf != NULL) { 403 ASSERT(buf->b_data != NULL); 404 db->db.db_data = buf->b_data; 405 if (!arc_released(buf)) 406 arc_set_callback(buf, dbuf_do_evict, db); 407 dbuf_update_data(db); 408 } else { 409 dbuf_evict_user(db); 410 db->db.db_data = NULL; 411 if (db->db_state != DB_NOFILL) 412 db->db_state = DB_UNCACHED; 413 } 414 } 415 416 /* 417 * Loan out an arc_buf for read. Return the loaned arc_buf. 418 */ 419 arc_buf_t * 420 dbuf_loan_arcbuf(dmu_buf_impl_t *db) 421 { 422 arc_buf_t *abuf; 423 424 mutex_enter(&db->db_mtx); 425 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) { 426 int blksz = db->db.db_size; 427 mutex_exit(&db->db_mtx); 428 abuf = arc_loan_buf(db->db_dnode->dn_objset->os_spa, blksz); 429 bcopy(db->db.db_data, abuf->b_data, blksz); 430 } else { 431 abuf = db->db_buf; 432 arc_loan_inuse_buf(abuf, db); 433 dbuf_set_data(db, NULL); 434 mutex_exit(&db->db_mtx); 435 } 436 return (abuf); 437 } 438 439 uint64_t 440 dbuf_whichblock(dnode_t *dn, uint64_t offset) 441 { 442 if (dn->dn_datablkshift) { 443 return (offset >> dn->dn_datablkshift); 444 } else { 445 ASSERT3U(offset, <, dn->dn_datablksz); 446 return (0); 447 } 448 } 449 450 static void 451 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb) 452 { 453 dmu_buf_impl_t *db = vdb; 454 455 mutex_enter(&db->db_mtx); 456 ASSERT3U(db->db_state, ==, DB_READ); 457 /* 458 * All reads are synchronous, so we must have a hold on the dbuf 459 */ 460 ASSERT(refcount_count(&db->db_holds) > 0); 461 ASSERT(db->db_buf == NULL); 462 ASSERT(db->db.db_data == NULL); 463 if (db->db_level == 0 && db->db_freed_in_flight) { 464 /* we were freed in flight; disregard any error */ 465 arc_release(buf, db); 466 bzero(buf->b_data, db->db.db_size); 467 arc_buf_freeze(buf); 468 db->db_freed_in_flight = FALSE; 469 dbuf_set_data(db, buf); 470 db->db_state = DB_CACHED; 471 } else if (zio == NULL || zio->io_error == 0) { 472 dbuf_set_data(db, buf); 473 db->db_state = DB_CACHED; 474 } else { 475 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 476 ASSERT3P(db->db_buf, ==, NULL); 477 VERIFY(arc_buf_remove_ref(buf, db) == 1); 478 db->db_state = DB_UNCACHED; 479 } 480 cv_broadcast(&db->db_changed); 481 dbuf_rele_and_unlock(db, NULL); 482 } 483 484 static void 485 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags) 486 { 487 dnode_t *dn = db->db_dnode; 488 zbookmark_t zb; 489 uint32_t aflags = ARC_NOWAIT; 490 arc_buf_t *pbuf; 491 492 ASSERT(!refcount_is_zero(&db->db_holds)); 493 /* We need the struct_rwlock to prevent db_blkptr from changing. */ 494 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 495 ASSERT(MUTEX_HELD(&db->db_mtx)); 496 ASSERT(db->db_state == DB_UNCACHED); 497 ASSERT(db->db_buf == NULL); 498 499 if (db->db_blkid == DMU_BONUS_BLKID) { 500 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen); 501 502 ASSERT3U(bonuslen, <=, db->db.db_size); 503 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN); 504 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 505 if (bonuslen < DN_MAX_BONUSLEN) 506 bzero(db->db.db_data, DN_MAX_BONUSLEN); 507 if (bonuslen) 508 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen); 509 dbuf_update_data(db); 510 db->db_state = DB_CACHED; 511 mutex_exit(&db->db_mtx); 512 return; 513 } 514 515 /* 516 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync() 517 * processes the delete record and clears the bp while we are waiting 518 * for the dn_mtx (resulting in a "no" from block_freed). 519 */ 520 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) || 521 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) || 522 BP_IS_HOLE(db->db_blkptr)))) { 523 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 524 525 dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa, 526 db->db.db_size, db, type)); 527 bzero(db->db.db_data, db->db.db_size); 528 db->db_state = DB_CACHED; 529 *flags |= DB_RF_CACHED; 530 mutex_exit(&db->db_mtx); 531 return; 532 } 533 534 db->db_state = DB_READ; 535 mutex_exit(&db->db_mtx); 536 537 if (DBUF_IS_L2CACHEABLE(db)) 538 aflags |= ARC_L2CACHE; 539 540 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ? 541 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET, 542 db->db.db_object, db->db_level, db->db_blkid); 543 544 dbuf_add_ref(db, NULL); 545 /* ZIO_FLAG_CANFAIL callers have to check the parent zio's error */ 546 547 if (db->db_parent) 548 pbuf = db->db_parent->db_buf; 549 else 550 pbuf = db->db_objset->os_phys_buf; 551 552 (void) dsl_read(zio, dn->dn_objset->os_spa, db->db_blkptr, pbuf, 553 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ, 554 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED, 555 &aflags, &zb); 556 if (aflags & ARC_CACHED) 557 *flags |= DB_RF_CACHED; 558 } 559 560 int 561 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) 562 { 563 int err = 0; 564 int havepzio = (zio != NULL); 565 int prefetch; 566 567 /* 568 * We don't have to hold the mutex to check db_state because it 569 * can't be freed while we have a hold on the buffer. 570 */ 571 ASSERT(!refcount_is_zero(&db->db_holds)); 572 573 if (db->db_state == DB_NOFILL) 574 return (EIO); 575 576 if ((flags & DB_RF_HAVESTRUCT) == 0) 577 rw_enter(&db->db_dnode->dn_struct_rwlock, RW_READER); 578 579 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 580 (flags & DB_RF_NOPREFETCH) == 0 && db->db_dnode != NULL && 581 DBUF_IS_CACHEABLE(db); 582 583 mutex_enter(&db->db_mtx); 584 if (db->db_state == DB_CACHED) { 585 mutex_exit(&db->db_mtx); 586 if (prefetch) 587 dmu_zfetch(&db->db_dnode->dn_zfetch, db->db.db_offset, 588 db->db.db_size, TRUE); 589 if ((flags & DB_RF_HAVESTRUCT) == 0) 590 rw_exit(&db->db_dnode->dn_struct_rwlock); 591 } else if (db->db_state == DB_UNCACHED) { 592 if (zio == NULL) { 593 zio = zio_root(db->db_dnode->dn_objset->os_spa, 594 NULL, NULL, ZIO_FLAG_CANFAIL); 595 } 596 dbuf_read_impl(db, zio, &flags); 597 598 /* dbuf_read_impl has dropped db_mtx for us */ 599 600 if (prefetch) 601 dmu_zfetch(&db->db_dnode->dn_zfetch, db->db.db_offset, 602 db->db.db_size, flags & DB_RF_CACHED); 603 604 if ((flags & DB_RF_HAVESTRUCT) == 0) 605 rw_exit(&db->db_dnode->dn_struct_rwlock); 606 607 if (!havepzio) 608 err = zio_wait(zio); 609 } else { 610 mutex_exit(&db->db_mtx); 611 if (prefetch) 612 dmu_zfetch(&db->db_dnode->dn_zfetch, db->db.db_offset, 613 db->db.db_size, TRUE); 614 if ((flags & DB_RF_HAVESTRUCT) == 0) 615 rw_exit(&db->db_dnode->dn_struct_rwlock); 616 617 mutex_enter(&db->db_mtx); 618 if ((flags & DB_RF_NEVERWAIT) == 0) { 619 while (db->db_state == DB_READ || 620 db->db_state == DB_FILL) { 621 ASSERT(db->db_state == DB_READ || 622 (flags & DB_RF_HAVESTRUCT) == 0); 623 cv_wait(&db->db_changed, &db->db_mtx); 624 } 625 if (db->db_state == DB_UNCACHED) 626 err = EIO; 627 } 628 mutex_exit(&db->db_mtx); 629 } 630 631 ASSERT(err || havepzio || db->db_state == DB_CACHED); 632 return (err); 633 } 634 635 static void 636 dbuf_noread(dmu_buf_impl_t *db) 637 { 638 ASSERT(!refcount_is_zero(&db->db_holds)); 639 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 640 mutex_enter(&db->db_mtx); 641 while (db->db_state == DB_READ || db->db_state == DB_FILL) 642 cv_wait(&db->db_changed, &db->db_mtx); 643 if (db->db_state == DB_UNCACHED) { 644 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 645 646 ASSERT(db->db_buf == NULL); 647 ASSERT(db->db.db_data == NULL); 648 dbuf_set_data(db, arc_buf_alloc(db->db_dnode->dn_objset->os_spa, 649 db->db.db_size, db, type)); 650 db->db_state = DB_FILL; 651 } else if (db->db_state == DB_NOFILL) { 652 dbuf_set_data(db, NULL); 653 } else { 654 ASSERT3U(db->db_state, ==, DB_CACHED); 655 } 656 mutex_exit(&db->db_mtx); 657 } 658 659 /* 660 * This is our just-in-time copy function. It makes a copy of 661 * buffers, that have been modified in a previous transaction 662 * group, before we modify them in the current active group. 663 * 664 * This function is used in two places: when we are dirtying a 665 * buffer for the first time in a txg, and when we are freeing 666 * a range in a dnode that includes this buffer. 667 * 668 * Note that when we are called from dbuf_free_range() we do 669 * not put a hold on the buffer, we just traverse the active 670 * dbuf list for the dnode. 671 */ 672 static void 673 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg) 674 { 675 dbuf_dirty_record_t *dr = db->db_last_dirty; 676 677 ASSERT(MUTEX_HELD(&db->db_mtx)); 678 ASSERT(db->db.db_data != NULL); 679 ASSERT(db->db_level == 0); 680 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT); 681 682 if (dr == NULL || 683 (dr->dt.dl.dr_data != 684 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf))) 685 return; 686 687 /* 688 * If the last dirty record for this dbuf has not yet synced 689 * and its referencing the dbuf data, either: 690 * reset the reference to point to a new copy, 691 * or (if there a no active holders) 692 * just null out the current db_data pointer. 693 */ 694 ASSERT(dr->dr_txg >= txg - 2); 695 if (db->db_blkid == DMU_BONUS_BLKID) { 696 /* Note that the data bufs here are zio_bufs */ 697 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN); 698 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 699 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN); 700 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) { 701 int size = db->db.db_size; 702 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 703 dr->dt.dl.dr_data = arc_buf_alloc( 704 db->db_dnode->dn_objset->os_spa, size, db, type); 705 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size); 706 } else { 707 dbuf_set_data(db, NULL); 708 } 709 } 710 711 void 712 dbuf_unoverride(dbuf_dirty_record_t *dr) 713 { 714 dmu_buf_impl_t *db = dr->dr_dbuf; 715 blkptr_t *bp = &dr->dt.dl.dr_overridden_by; 716 uint64_t txg = dr->dr_txg; 717 718 ASSERT(MUTEX_HELD(&db->db_mtx)); 719 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC); 720 ASSERT(db->db_level == 0); 721 722 if (db->db_blkid == DMU_BONUS_BLKID || 723 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN) 724 return; 725 726 ASSERT(db->db_data_pending != dr); 727 728 /* free this block */ 729 if (!BP_IS_HOLE(bp)) 730 zio_free(db->db_dnode->dn_objset->os_spa, txg, bp); 731 732 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 733 /* 734 * Release the already-written buffer, so we leave it in 735 * a consistent dirty state. Note that all callers are 736 * modifying the buffer, so they will immediately do 737 * another (redundant) arc_release(). Therefore, leave 738 * the buf thawed to save the effort of freezing & 739 * immediately re-thawing it. 740 */ 741 arc_release(dr->dt.dl.dr_data, db); 742 } 743 744 /* 745 * Evict (if its unreferenced) or clear (if its referenced) any level-0 746 * data blocks in the free range, so that any future readers will find 747 * empty blocks. Also, if we happen accross any level-1 dbufs in the 748 * range that have not already been marked dirty, mark them dirty so 749 * they stay in memory. 750 */ 751 void 752 dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx) 753 { 754 dmu_buf_impl_t *db, *db_next; 755 uint64_t txg = tx->tx_txg; 756 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 757 uint64_t first_l1 = start >> epbs; 758 uint64_t last_l1 = end >> epbs; 759 760 if (end > dn->dn_maxblkid && (end != DMU_SPILL_BLKID)) { 761 end = dn->dn_maxblkid; 762 last_l1 = end >> epbs; 763 } 764 dprintf_dnode(dn, "start=%llu end=%llu\n", start, end); 765 mutex_enter(&dn->dn_dbufs_mtx); 766 for (db = list_head(&dn->dn_dbufs); db; db = db_next) { 767 db_next = list_next(&dn->dn_dbufs, db); 768 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 769 770 if (db->db_level == 1 && 771 db->db_blkid >= first_l1 && db->db_blkid <= last_l1) { 772 mutex_enter(&db->db_mtx); 773 if (db->db_last_dirty && 774 db->db_last_dirty->dr_txg < txg) { 775 dbuf_add_ref(db, FTAG); 776 mutex_exit(&db->db_mtx); 777 dbuf_will_dirty(db, tx); 778 dbuf_rele(db, FTAG); 779 } else { 780 mutex_exit(&db->db_mtx); 781 } 782 } 783 784 if (db->db_level != 0) 785 continue; 786 dprintf_dbuf(db, "found buf %s\n", ""); 787 if (db->db_blkid < start || db->db_blkid > end) 788 continue; 789 790 /* found a level 0 buffer in the range */ 791 if (dbuf_undirty(db, tx)) 792 continue; 793 794 mutex_enter(&db->db_mtx); 795 if (db->db_state == DB_UNCACHED || 796 db->db_state == DB_NOFILL || 797 db->db_state == DB_EVICTING) { 798 ASSERT(db->db.db_data == NULL); 799 mutex_exit(&db->db_mtx); 800 continue; 801 } 802 if (db->db_state == DB_READ || db->db_state == DB_FILL) { 803 /* will be handled in dbuf_read_done or dbuf_rele */ 804 db->db_freed_in_flight = TRUE; 805 mutex_exit(&db->db_mtx); 806 continue; 807 } 808 if (refcount_count(&db->db_holds) == 0) { 809 ASSERT(db->db_buf); 810 dbuf_clear(db); 811 continue; 812 } 813 /* The dbuf is referenced */ 814 815 if (db->db_last_dirty != NULL) { 816 dbuf_dirty_record_t *dr = db->db_last_dirty; 817 818 if (dr->dr_txg == txg) { 819 /* 820 * This buffer is "in-use", re-adjust the file 821 * size to reflect that this buffer may 822 * contain new data when we sync. 823 */ 824 if (db->db_blkid != DMU_SPILL_BLKID && 825 db->db_blkid > dn->dn_maxblkid) 826 dn->dn_maxblkid = db->db_blkid; 827 dbuf_unoverride(dr); 828 } else { 829 /* 830 * This dbuf is not dirty in the open context. 831 * Either uncache it (if its not referenced in 832 * the open context) or reset its contents to 833 * empty. 834 */ 835 dbuf_fix_old_data(db, txg); 836 } 837 } 838 /* clear the contents if its cached */ 839 if (db->db_state == DB_CACHED) { 840 ASSERT(db->db.db_data != NULL); 841 arc_release(db->db_buf, db); 842 bzero(db->db.db_data, db->db.db_size); 843 arc_buf_freeze(db->db_buf); 844 } 845 846 mutex_exit(&db->db_mtx); 847 } 848 mutex_exit(&dn->dn_dbufs_mtx); 849 } 850 851 static int 852 dbuf_block_freeable(dmu_buf_impl_t *db) 853 { 854 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset; 855 uint64_t birth_txg = 0; 856 857 /* 858 * We don't need any locking to protect db_blkptr: 859 * If it's syncing, then db_last_dirty will be set 860 * so we'll ignore db_blkptr. 861 */ 862 ASSERT(MUTEX_HELD(&db->db_mtx)); 863 if (db->db_last_dirty) 864 birth_txg = db->db_last_dirty->dr_txg; 865 else if (db->db_blkptr) 866 birth_txg = db->db_blkptr->blk_birth; 867 868 /* If we don't exist or are in a snapshot, we can't be freed */ 869 if (birth_txg) 870 return (ds == NULL || 871 dsl_dataset_block_freeable(ds, birth_txg)); 872 else 873 return (FALSE); 874 } 875 876 void 877 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx) 878 { 879 arc_buf_t *buf, *obuf; 880 int osize = db->db.db_size; 881 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 882 883 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 884 885 /* XXX does *this* func really need the lock? */ 886 ASSERT(RW_WRITE_HELD(&db->db_dnode->dn_struct_rwlock)); 887 888 /* 889 * This call to dbuf_will_dirty() with the dn_struct_rwlock held 890 * is OK, because there can be no other references to the db 891 * when we are changing its size, so no concurrent DB_FILL can 892 * be happening. 893 */ 894 /* 895 * XXX we should be doing a dbuf_read, checking the return 896 * value and returning that up to our callers 897 */ 898 dbuf_will_dirty(db, tx); 899 900 /* create the data buffer for the new block */ 901 buf = arc_buf_alloc(db->db_dnode->dn_objset->os_spa, size, db, type); 902 903 /* copy old block data to the new block */ 904 obuf = db->db_buf; 905 bcopy(obuf->b_data, buf->b_data, MIN(osize, size)); 906 /* zero the remainder */ 907 if (size > osize) 908 bzero((uint8_t *)buf->b_data + osize, size - osize); 909 910 mutex_enter(&db->db_mtx); 911 dbuf_set_data(db, buf); 912 VERIFY(arc_buf_remove_ref(obuf, db) == 1); 913 db->db.db_size = size; 914 915 if (db->db_level == 0) { 916 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg); 917 db->db_last_dirty->dt.dl.dr_data = buf; 918 } 919 mutex_exit(&db->db_mtx); 920 921 dnode_willuse_space(db->db_dnode, size-osize, tx); 922 } 923 924 void 925 dbuf_release_bp(dmu_buf_impl_t *db) 926 { 927 objset_t *os = db->db_dnode->dn_objset; 928 zbookmark_t zb; 929 930 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os))); 931 ASSERT(arc_released(os->os_phys_buf) || 932 list_link_active(&os->os_dsl_dataset->ds_synced_link)); 933 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf)); 934 935 zb.zb_objset = os->os_dsl_dataset ? 936 os->os_dsl_dataset->ds_object : 0; 937 zb.zb_object = db->db.db_object; 938 zb.zb_level = db->db_level; 939 zb.zb_blkid = db->db_blkid; 940 (void) arc_release_bp(db->db_buf, db, 941 db->db_blkptr, os->os_spa, &zb); 942 } 943 944 dbuf_dirty_record_t * 945 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 946 { 947 dnode_t *dn = db->db_dnode; 948 objset_t *os = dn->dn_objset; 949 dbuf_dirty_record_t **drp, *dr; 950 int drop_struct_lock = FALSE; 951 boolean_t do_free_accounting = B_FALSE; 952 int txgoff = tx->tx_txg & TXG_MASK; 953 954 ASSERT(tx->tx_txg != 0); 955 ASSERT(!refcount_is_zero(&db->db_holds)); 956 DMU_TX_DIRTY_BUF(tx, db); 957 958 /* 959 * Shouldn't dirty a regular buffer in syncing context. Private 960 * objects may be dirtied in syncing context, but only if they 961 * were already pre-dirtied in open context. 962 */ 963 ASSERT(!dmu_tx_is_syncing(tx) || 964 BP_IS_HOLE(dn->dn_objset->os_rootbp) || 965 DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 966 dn->dn_objset->os_dsl_dataset == NULL); 967 /* 968 * We make this assert for private objects as well, but after we 969 * check if we're already dirty. They are allowed to re-dirty 970 * in syncing context. 971 */ 972 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 973 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 974 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 975 976 mutex_enter(&db->db_mtx); 977 /* 978 * XXX make this true for indirects too? The problem is that 979 * transactions created with dmu_tx_create_assigned() from 980 * syncing context don't bother holding ahead. 981 */ 982 ASSERT(db->db_level != 0 || 983 db->db_state == DB_CACHED || db->db_state == DB_FILL || 984 db->db_state == DB_NOFILL); 985 986 mutex_enter(&dn->dn_mtx); 987 /* 988 * Don't set dirtyctx to SYNC if we're just modifying this as we 989 * initialize the objset. 990 */ 991 if (dn->dn_dirtyctx == DN_UNDIRTIED && 992 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) { 993 dn->dn_dirtyctx = 994 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN); 995 ASSERT(dn->dn_dirtyctx_firstset == NULL); 996 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP); 997 } 998 mutex_exit(&dn->dn_mtx); 999 1000 if (db->db_blkid == DMU_SPILL_BLKID) 1001 dn->dn_have_spill = B_TRUE; 1002 1003 /* 1004 * If this buffer is already dirty, we're done. 1005 */ 1006 drp = &db->db_last_dirty; 1007 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg || 1008 db->db.db_object == DMU_META_DNODE_OBJECT); 1009 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg) 1010 drp = &dr->dr_next; 1011 if (dr && dr->dr_txg == tx->tx_txg) { 1012 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) { 1013 /* 1014 * If this buffer has already been written out, 1015 * we now need to reset its state. 1016 */ 1017 dbuf_unoverride(dr); 1018 if (db->db.db_object != DMU_META_DNODE_OBJECT && 1019 db->db_state != DB_NOFILL) 1020 arc_buf_thaw(db->db_buf); 1021 } 1022 mutex_exit(&db->db_mtx); 1023 return (dr); 1024 } 1025 1026 /* 1027 * Only valid if not already dirty. 1028 */ 1029 ASSERT(dn->dn_object == 0 || 1030 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == 1031 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); 1032 1033 ASSERT3U(dn->dn_nlevels, >, db->db_level); 1034 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) || 1035 dn->dn_phys->dn_nlevels > db->db_level || 1036 dn->dn_next_nlevels[txgoff] > db->db_level || 1037 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level || 1038 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level); 1039 1040 /* 1041 * We should only be dirtying in syncing context if it's the 1042 * mos or we're initializing the os or it's a special object. 1043 * However, we are allowed to dirty in syncing context provided 1044 * we already dirtied it in open context. Hence we must make 1045 * this assertion only if we're not already dirty. 1046 */ 1047 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) || 1048 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp)); 1049 ASSERT(db->db.db_size != 0); 1050 1051 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1052 1053 if (db->db_blkid != DMU_BONUS_BLKID) { 1054 /* 1055 * Update the accounting. 1056 * Note: we delay "free accounting" until after we drop 1057 * the db_mtx. This keeps us from grabbing other locks 1058 * (and possibly deadlocking) in bp_get_dsize() while 1059 * also holding the db_mtx. 1060 */ 1061 dnode_willuse_space(dn, db->db.db_size, tx); 1062 do_free_accounting = dbuf_block_freeable(db); 1063 } 1064 1065 /* 1066 * If this buffer is dirty in an old transaction group we need 1067 * to make a copy of it so that the changes we make in this 1068 * transaction group won't leak out when we sync the older txg. 1069 */ 1070 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP); 1071 if (db->db_level == 0) { 1072 void *data_old = db->db_buf; 1073 1074 if (db->db_state != DB_NOFILL) { 1075 if (db->db_blkid == DMU_BONUS_BLKID) { 1076 dbuf_fix_old_data(db, tx->tx_txg); 1077 data_old = db->db.db_data; 1078 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) { 1079 /* 1080 * Release the data buffer from the cache so 1081 * that we can modify it without impacting 1082 * possible other users of this cached data 1083 * block. Note that indirect blocks and 1084 * private objects are not released until the 1085 * syncing state (since they are only modified 1086 * then). 1087 */ 1088 arc_release(db->db_buf, db); 1089 dbuf_fix_old_data(db, tx->tx_txg); 1090 data_old = db->db_buf; 1091 } 1092 ASSERT(data_old != NULL); 1093 } 1094 dr->dt.dl.dr_data = data_old; 1095 } else { 1096 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL); 1097 list_create(&dr->dt.di.dr_children, 1098 sizeof (dbuf_dirty_record_t), 1099 offsetof(dbuf_dirty_record_t, dr_dirty_node)); 1100 } 1101 dr->dr_dbuf = db; 1102 dr->dr_txg = tx->tx_txg; 1103 dr->dr_next = *drp; 1104 *drp = dr; 1105 1106 /* 1107 * We could have been freed_in_flight between the dbuf_noread 1108 * and dbuf_dirty. We win, as though the dbuf_noread() had 1109 * happened after the free. 1110 */ 1111 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1112 db->db_blkid != DMU_SPILL_BLKID) { 1113 mutex_enter(&dn->dn_mtx); 1114 dnode_clear_range(dn, db->db_blkid, 1, tx); 1115 mutex_exit(&dn->dn_mtx); 1116 db->db_freed_in_flight = FALSE; 1117 } 1118 1119 /* 1120 * This buffer is now part of this txg 1121 */ 1122 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg); 1123 db->db_dirtycnt += 1; 1124 ASSERT3U(db->db_dirtycnt, <=, 3); 1125 1126 mutex_exit(&db->db_mtx); 1127 1128 if (db->db_blkid == DMU_BONUS_BLKID || 1129 db->db_blkid == DMU_SPILL_BLKID) { 1130 mutex_enter(&dn->dn_mtx); 1131 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1132 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1133 mutex_exit(&dn->dn_mtx); 1134 dnode_setdirty(dn, tx); 1135 return (dr); 1136 } else if (do_free_accounting) { 1137 blkptr_t *bp = db->db_blkptr; 1138 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ? 1139 bp_get_dsize(os->os_spa, bp) : db->db.db_size; 1140 /* 1141 * This is only a guess -- if the dbuf is dirty 1142 * in a previous txg, we don't know how much 1143 * space it will use on disk yet. We should 1144 * really have the struct_rwlock to access 1145 * db_blkptr, but since this is just a guess, 1146 * it's OK if we get an odd answer. 1147 */ 1148 dnode_willuse_space(dn, -willfree, tx); 1149 } 1150 1151 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 1152 rw_enter(&dn->dn_struct_rwlock, RW_READER); 1153 drop_struct_lock = TRUE; 1154 } 1155 1156 if (db->db_level == 0) { 1157 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock); 1158 ASSERT(dn->dn_maxblkid >= db->db_blkid); 1159 } 1160 1161 if (db->db_level+1 < dn->dn_nlevels) { 1162 dmu_buf_impl_t *parent = db->db_parent; 1163 dbuf_dirty_record_t *di; 1164 int parent_held = FALSE; 1165 1166 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) { 1167 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1168 1169 parent = dbuf_hold_level(dn, db->db_level+1, 1170 db->db_blkid >> epbs, FTAG); 1171 ASSERT(parent != NULL); 1172 parent_held = TRUE; 1173 } 1174 if (drop_struct_lock) 1175 rw_exit(&dn->dn_struct_rwlock); 1176 ASSERT3U(db->db_level+1, ==, parent->db_level); 1177 di = dbuf_dirty(parent, tx); 1178 if (parent_held) 1179 dbuf_rele(parent, FTAG); 1180 1181 mutex_enter(&db->db_mtx); 1182 /* possible race with dbuf_undirty() */ 1183 if (db->db_last_dirty == dr || 1184 dn->dn_object == DMU_META_DNODE_OBJECT) { 1185 mutex_enter(&di->dt.di.dr_mtx); 1186 ASSERT3U(di->dr_txg, ==, tx->tx_txg); 1187 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1188 list_insert_tail(&di->dt.di.dr_children, dr); 1189 mutex_exit(&di->dt.di.dr_mtx); 1190 dr->dr_parent = di; 1191 } 1192 mutex_exit(&db->db_mtx); 1193 } else { 1194 ASSERT(db->db_level+1 == dn->dn_nlevels); 1195 ASSERT(db->db_blkid < dn->dn_nblkptr); 1196 ASSERT(db->db_parent == NULL || 1197 db->db_parent == db->db_dnode->dn_dbuf); 1198 mutex_enter(&dn->dn_mtx); 1199 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1200 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1201 mutex_exit(&dn->dn_mtx); 1202 if (drop_struct_lock) 1203 rw_exit(&dn->dn_struct_rwlock); 1204 } 1205 1206 dnode_setdirty(dn, tx); 1207 return (dr); 1208 } 1209 1210 static int 1211 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1212 { 1213 dnode_t *dn = db->db_dnode; 1214 uint64_t txg = tx->tx_txg; 1215 dbuf_dirty_record_t *dr, **drp; 1216 1217 ASSERT(txg != 0); 1218 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1219 1220 mutex_enter(&db->db_mtx); 1221 /* 1222 * If this buffer is not dirty, we're done. 1223 */ 1224 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next) 1225 if (dr->dr_txg <= txg) 1226 break; 1227 if (dr == NULL || dr->dr_txg < txg) { 1228 mutex_exit(&db->db_mtx); 1229 return (0); 1230 } 1231 ASSERT(dr->dr_txg == txg); 1232 ASSERT(dr->dr_dbuf == db); 1233 1234 /* 1235 * If this buffer is currently held, we cannot undirty 1236 * it, since one of the current holders may be in the 1237 * middle of an update. Note that users of dbuf_undirty() 1238 * should not place a hold on the dbuf before the call. 1239 */ 1240 if (refcount_count(&db->db_holds) > db->db_dirtycnt) { 1241 mutex_exit(&db->db_mtx); 1242 /* Make sure we don't toss this buffer at sync phase */ 1243 mutex_enter(&dn->dn_mtx); 1244 dnode_clear_range(dn, db->db_blkid, 1, tx); 1245 mutex_exit(&dn->dn_mtx); 1246 return (0); 1247 } 1248 1249 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1250 1251 ASSERT(db->db.db_size != 0); 1252 1253 /* XXX would be nice to fix up dn_towrite_space[] */ 1254 1255 *drp = dr->dr_next; 1256 1257 if (dr->dr_parent) { 1258 mutex_enter(&dr->dr_parent->dt.di.dr_mtx); 1259 list_remove(&dr->dr_parent->dt.di.dr_children, dr); 1260 mutex_exit(&dr->dr_parent->dt.di.dr_mtx); 1261 } else if (db->db_level+1 == dn->dn_nlevels) { 1262 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf); 1263 mutex_enter(&dn->dn_mtx); 1264 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr); 1265 mutex_exit(&dn->dn_mtx); 1266 } 1267 1268 if (db->db_level == 0) { 1269 if (db->db_state != DB_NOFILL) { 1270 dbuf_unoverride(dr); 1271 1272 ASSERT(db->db_buf != NULL); 1273 ASSERT(dr->dt.dl.dr_data != NULL); 1274 if (dr->dt.dl.dr_data != db->db_buf) 1275 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 1276 db) == 1); 1277 } 1278 } else { 1279 ASSERT(db->db_buf != NULL); 1280 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 1281 mutex_destroy(&dr->dt.di.dr_mtx); 1282 list_destroy(&dr->dt.di.dr_children); 1283 } 1284 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 1285 1286 ASSERT(db->db_dirtycnt > 0); 1287 db->db_dirtycnt -= 1; 1288 1289 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) { 1290 arc_buf_t *buf = db->db_buf; 1291 1292 ASSERT(db->db_state == DB_NOFILL || arc_released(buf)); 1293 dbuf_set_data(db, NULL); 1294 VERIFY(arc_buf_remove_ref(buf, db) == 1); 1295 dbuf_evict(db); 1296 return (1); 1297 } 1298 1299 mutex_exit(&db->db_mtx); 1300 return (0); 1301 } 1302 1303 #pragma weak dmu_buf_will_dirty = dbuf_will_dirty 1304 void 1305 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1306 { 1307 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH; 1308 1309 ASSERT(tx->tx_txg != 0); 1310 ASSERT(!refcount_is_zero(&db->db_holds)); 1311 1312 if (RW_WRITE_HELD(&db->db_dnode->dn_struct_rwlock)) 1313 rf |= DB_RF_HAVESTRUCT; 1314 (void) dbuf_read(db, NULL, rf); 1315 (void) dbuf_dirty(db, tx); 1316 } 1317 1318 void 1319 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1320 { 1321 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1322 1323 db->db_state = DB_NOFILL; 1324 1325 dmu_buf_will_fill(db_fake, tx); 1326 } 1327 1328 void 1329 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1330 { 1331 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1332 1333 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1334 ASSERT(tx->tx_txg != 0); 1335 ASSERT(db->db_level == 0); 1336 ASSERT(!refcount_is_zero(&db->db_holds)); 1337 1338 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT || 1339 dmu_tx_private_ok(tx)); 1340 1341 dbuf_noread(db); 1342 (void) dbuf_dirty(db, tx); 1343 } 1344 1345 #pragma weak dmu_buf_fill_done = dbuf_fill_done 1346 /* ARGSUSED */ 1347 void 1348 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx) 1349 { 1350 mutex_enter(&db->db_mtx); 1351 DBUF_VERIFY(db); 1352 1353 if (db->db_state == DB_FILL) { 1354 if (db->db_level == 0 && db->db_freed_in_flight) { 1355 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1356 /* we were freed while filling */ 1357 /* XXX dbuf_undirty? */ 1358 bzero(db->db.db_data, db->db.db_size); 1359 db->db_freed_in_flight = FALSE; 1360 } 1361 db->db_state = DB_CACHED; 1362 cv_broadcast(&db->db_changed); 1363 } 1364 mutex_exit(&db->db_mtx); 1365 } 1366 1367 /* 1368 * Directly assign a provided arc buf to a given dbuf if it's not referenced 1369 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf. 1370 */ 1371 void 1372 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx) 1373 { 1374 ASSERT(!refcount_is_zero(&db->db_holds)); 1375 ASSERT(db->db_dnode->dn_object != DMU_META_DNODE_OBJECT); 1376 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1377 ASSERT(db->db_level == 0); 1378 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA); 1379 ASSERT(buf != NULL); 1380 ASSERT(arc_buf_size(buf) == db->db.db_size); 1381 ASSERT(tx->tx_txg != 0); 1382 1383 arc_return_buf(buf, db); 1384 ASSERT(arc_released(buf)); 1385 1386 mutex_enter(&db->db_mtx); 1387 1388 while (db->db_state == DB_READ || db->db_state == DB_FILL) 1389 cv_wait(&db->db_changed, &db->db_mtx); 1390 1391 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED); 1392 1393 if (db->db_state == DB_CACHED && 1394 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) { 1395 mutex_exit(&db->db_mtx); 1396 (void) dbuf_dirty(db, tx); 1397 bcopy(buf->b_data, db->db.db_data, db->db.db_size); 1398 VERIFY(arc_buf_remove_ref(buf, db) == 1); 1399 xuio_stat_wbuf_copied(); 1400 return; 1401 } 1402 1403 xuio_stat_wbuf_nocopy(); 1404 if (db->db_state == DB_CACHED) { 1405 dbuf_dirty_record_t *dr = db->db_last_dirty; 1406 1407 ASSERT(db->db_buf != NULL); 1408 if (dr != NULL && dr->dr_txg == tx->tx_txg) { 1409 ASSERT(dr->dt.dl.dr_data == db->db_buf); 1410 if (!arc_released(db->db_buf)) { 1411 ASSERT(dr->dt.dl.dr_override_state == 1412 DR_OVERRIDDEN); 1413 arc_release(db->db_buf, db); 1414 } 1415 dr->dt.dl.dr_data = buf; 1416 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1); 1417 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) { 1418 arc_release(db->db_buf, db); 1419 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1); 1420 } 1421 db->db_buf = NULL; 1422 } 1423 ASSERT(db->db_buf == NULL); 1424 dbuf_set_data(db, buf); 1425 db->db_state = DB_FILL; 1426 mutex_exit(&db->db_mtx); 1427 (void) dbuf_dirty(db, tx); 1428 dbuf_fill_done(db, tx); 1429 } 1430 1431 /* 1432 * "Clear" the contents of this dbuf. This will mark the dbuf 1433 * EVICTING and clear *most* of its references. Unfortunetely, 1434 * when we are not holding the dn_dbufs_mtx, we can't clear the 1435 * entry in the dn_dbufs list. We have to wait until dbuf_destroy() 1436 * in this case. For callers from the DMU we will usually see: 1437 * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy() 1438 * For the arc callback, we will usually see: 1439 * dbuf_do_evict()->dbuf_clear();dbuf_destroy() 1440 * Sometimes, though, we will get a mix of these two: 1441 * DMU: dbuf_clear()->arc_buf_evict() 1442 * ARC: dbuf_do_evict()->dbuf_destroy() 1443 */ 1444 void 1445 dbuf_clear(dmu_buf_impl_t *db) 1446 { 1447 dnode_t *dn = db->db_dnode; 1448 dmu_buf_impl_t *parent = db->db_parent; 1449 dmu_buf_impl_t *dndb = dn->dn_dbuf; 1450 int dbuf_gone = FALSE; 1451 1452 ASSERT(MUTEX_HELD(&db->db_mtx)); 1453 ASSERT(refcount_is_zero(&db->db_holds)); 1454 1455 dbuf_evict_user(db); 1456 1457 if (db->db_state == DB_CACHED) { 1458 ASSERT(db->db.db_data != NULL); 1459 if (db->db_blkid == DMU_BONUS_BLKID) { 1460 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN); 1461 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 1462 } 1463 db->db.db_data = NULL; 1464 db->db_state = DB_UNCACHED; 1465 } 1466 1467 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL); 1468 ASSERT(db->db_data_pending == NULL); 1469 1470 db->db_state = DB_EVICTING; 1471 db->db_blkptr = NULL; 1472 1473 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) { 1474 list_remove(&dn->dn_dbufs, db); 1475 dnode_rele(dn, db); 1476 db->db_dnode = NULL; 1477 } 1478 1479 if (db->db_buf) 1480 dbuf_gone = arc_buf_evict(db->db_buf); 1481 1482 if (!dbuf_gone) 1483 mutex_exit(&db->db_mtx); 1484 1485 /* 1486 * If this dbuf is referened from an indirect dbuf, 1487 * decrement the ref count on the indirect dbuf. 1488 */ 1489 if (parent && parent != dndb) 1490 dbuf_rele(parent, db); 1491 } 1492 1493 static int 1494 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, 1495 dmu_buf_impl_t **parentp, blkptr_t **bpp) 1496 { 1497 int nlevels, epbs; 1498 1499 *parentp = NULL; 1500 *bpp = NULL; 1501 1502 ASSERT(blkid != DMU_BONUS_BLKID); 1503 1504 if (blkid == DMU_SPILL_BLKID) { 1505 mutex_enter(&dn->dn_mtx); 1506 if (dn->dn_have_spill && 1507 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) 1508 *bpp = &dn->dn_phys->dn_spill; 1509 else 1510 *bpp = NULL; 1511 dbuf_add_ref(dn->dn_dbuf, NULL); 1512 *parentp = dn->dn_dbuf; 1513 mutex_exit(&dn->dn_mtx); 1514 return (0); 1515 } 1516 1517 if (dn->dn_phys->dn_nlevels == 0) 1518 nlevels = 1; 1519 else 1520 nlevels = dn->dn_phys->dn_nlevels; 1521 1522 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1523 1524 ASSERT3U(level * epbs, <, 64); 1525 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1526 if (level >= nlevels || 1527 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) { 1528 /* the buffer has no parent yet */ 1529 return (ENOENT); 1530 } else if (level < nlevels-1) { 1531 /* this block is referenced from an indirect block */ 1532 int err = dbuf_hold_impl(dn, level+1, 1533 blkid >> epbs, fail_sparse, NULL, parentp); 1534 if (err) 1535 return (err); 1536 err = dbuf_read(*parentp, NULL, 1537 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL)); 1538 if (err) { 1539 dbuf_rele(*parentp, NULL); 1540 *parentp = NULL; 1541 return (err); 1542 } 1543 *bpp = ((blkptr_t *)(*parentp)->db.db_data) + 1544 (blkid & ((1ULL << epbs) - 1)); 1545 return (0); 1546 } else { 1547 /* the block is referenced from the dnode */ 1548 ASSERT3U(level, ==, nlevels-1); 1549 ASSERT(dn->dn_phys->dn_nblkptr == 0 || 1550 blkid < dn->dn_phys->dn_nblkptr); 1551 if (dn->dn_dbuf) { 1552 dbuf_add_ref(dn->dn_dbuf, NULL); 1553 *parentp = dn->dn_dbuf; 1554 } 1555 *bpp = &dn->dn_phys->dn_blkptr[blkid]; 1556 return (0); 1557 } 1558 } 1559 1560 static dmu_buf_impl_t * 1561 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid, 1562 dmu_buf_impl_t *parent, blkptr_t *blkptr) 1563 { 1564 objset_t *os = dn->dn_objset; 1565 dmu_buf_impl_t *db, *odb; 1566 1567 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1568 ASSERT(dn->dn_type != DMU_OT_NONE); 1569 1570 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP); 1571 1572 db->db_objset = os; 1573 db->db.db_object = dn->dn_object; 1574 db->db_level = level; 1575 db->db_blkid = blkid; 1576 db->db_last_dirty = NULL; 1577 db->db_dirtycnt = 0; 1578 db->db_dnode = dn; 1579 db->db_parent = parent; 1580 db->db_blkptr = blkptr; 1581 1582 db->db_user_ptr = NULL; 1583 db->db_user_data_ptr_ptr = NULL; 1584 db->db_evict_func = NULL; 1585 db->db_immediate_evict = 0; 1586 db->db_freed_in_flight = 0; 1587 1588 if (blkid == DMU_BONUS_BLKID) { 1589 ASSERT3P(parent, ==, dn->dn_dbuf); 1590 db->db.db_size = DN_MAX_BONUSLEN - 1591 (dn->dn_nblkptr-1) * sizeof (blkptr_t); 1592 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 1593 db->db.db_offset = DMU_BONUS_BLKID; 1594 db->db_state = DB_UNCACHED; 1595 /* the bonus dbuf is not placed in the hash table */ 1596 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1597 return (db); 1598 } else if (blkid == DMU_SPILL_BLKID) { 1599 db->db.db_size = (blkptr != NULL) ? 1600 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE; 1601 db->db.db_offset = 0; 1602 } else { 1603 int blocksize = 1604 db->db_level ? 1<<dn->dn_indblkshift : dn->dn_datablksz; 1605 db->db.db_size = blocksize; 1606 db->db.db_offset = db->db_blkid * blocksize; 1607 } 1608 1609 /* 1610 * Hold the dn_dbufs_mtx while we get the new dbuf 1611 * in the hash table *and* added to the dbufs list. 1612 * This prevents a possible deadlock with someone 1613 * trying to look up this dbuf before its added to the 1614 * dn_dbufs list. 1615 */ 1616 mutex_enter(&dn->dn_dbufs_mtx); 1617 db->db_state = DB_EVICTING; 1618 if ((odb = dbuf_hash_insert(db)) != NULL) { 1619 /* someone else inserted it first */ 1620 kmem_cache_free(dbuf_cache, db); 1621 mutex_exit(&dn->dn_dbufs_mtx); 1622 return (odb); 1623 } 1624 list_insert_head(&dn->dn_dbufs, db); 1625 db->db_state = DB_UNCACHED; 1626 mutex_exit(&dn->dn_dbufs_mtx); 1627 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1628 1629 if (parent && parent != dn->dn_dbuf) 1630 dbuf_add_ref(parent, db); 1631 1632 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1633 refcount_count(&dn->dn_holds) > 0); 1634 (void) refcount_add(&dn->dn_holds, db); 1635 1636 dprintf_dbuf(db, "db=%p\n", db); 1637 1638 return (db); 1639 } 1640 1641 static int 1642 dbuf_do_evict(void *private) 1643 { 1644 arc_buf_t *buf = private; 1645 dmu_buf_impl_t *db = buf->b_private; 1646 1647 if (!MUTEX_HELD(&db->db_mtx)) 1648 mutex_enter(&db->db_mtx); 1649 1650 ASSERT(refcount_is_zero(&db->db_holds)); 1651 1652 if (db->db_state != DB_EVICTING) { 1653 ASSERT(db->db_state == DB_CACHED); 1654 DBUF_VERIFY(db); 1655 db->db_buf = NULL; 1656 dbuf_evict(db); 1657 } else { 1658 mutex_exit(&db->db_mtx); 1659 dbuf_destroy(db); 1660 } 1661 return (0); 1662 } 1663 1664 static void 1665 dbuf_destroy(dmu_buf_impl_t *db) 1666 { 1667 ASSERT(refcount_is_zero(&db->db_holds)); 1668 1669 if (db->db_blkid != DMU_BONUS_BLKID) { 1670 /* 1671 * If this dbuf is still on the dn_dbufs list, 1672 * remove it from that list. 1673 */ 1674 if (db->db_dnode) { 1675 dnode_t *dn = db->db_dnode; 1676 1677 mutex_enter(&dn->dn_dbufs_mtx); 1678 list_remove(&dn->dn_dbufs, db); 1679 mutex_exit(&dn->dn_dbufs_mtx); 1680 1681 dnode_rele(dn, db); 1682 db->db_dnode = NULL; 1683 } 1684 dbuf_hash_remove(db); 1685 } 1686 db->db_parent = NULL; 1687 db->db_buf = NULL; 1688 1689 ASSERT(!list_link_active(&db->db_link)); 1690 ASSERT(db->db.db_data == NULL); 1691 ASSERT(db->db_hash_next == NULL); 1692 ASSERT(db->db_blkptr == NULL); 1693 ASSERT(db->db_data_pending == NULL); 1694 1695 kmem_cache_free(dbuf_cache, db); 1696 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1697 } 1698 1699 void 1700 dbuf_prefetch(dnode_t *dn, uint64_t blkid) 1701 { 1702 dmu_buf_impl_t *db = NULL; 1703 blkptr_t *bp = NULL; 1704 1705 ASSERT(blkid != DMU_BONUS_BLKID); 1706 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1707 1708 if (dnode_block_freed(dn, blkid)) 1709 return; 1710 1711 /* dbuf_find() returns with db_mtx held */ 1712 if (db = dbuf_find(dn, 0, blkid)) { 1713 if (refcount_count(&db->db_holds) > 0) { 1714 /* 1715 * This dbuf is active. We assume that it is 1716 * already CACHED, or else about to be either 1717 * read or filled. 1718 */ 1719 mutex_exit(&db->db_mtx); 1720 return; 1721 } 1722 mutex_exit(&db->db_mtx); 1723 db = NULL; 1724 } 1725 1726 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) { 1727 if (bp && !BP_IS_HOLE(bp)) { 1728 arc_buf_t *pbuf; 1729 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; 1730 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH; 1731 zbookmark_t zb; 1732 1733 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET, 1734 dn->dn_object, 0, blkid); 1735 1736 if (db) 1737 pbuf = db->db_buf; 1738 else 1739 pbuf = dn->dn_objset->os_phys_buf; 1740 1741 (void) dsl_read(NULL, dn->dn_objset->os_spa, 1742 bp, pbuf, NULL, NULL, ZIO_PRIORITY_ASYNC_READ, 1743 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 1744 &aflags, &zb); 1745 } 1746 if (db) 1747 dbuf_rele(db, NULL); 1748 } 1749 } 1750 1751 /* 1752 * Returns with db_holds incremented, and db_mtx not held. 1753 * Note: dn_struct_rwlock must be held. 1754 */ 1755 int 1756 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse, 1757 void *tag, dmu_buf_impl_t **dbp) 1758 { 1759 dmu_buf_impl_t *db, *parent = NULL; 1760 1761 ASSERT(blkid != DMU_BONUS_BLKID); 1762 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1763 ASSERT3U(dn->dn_nlevels, >, level); 1764 1765 *dbp = NULL; 1766 top: 1767 /* dbuf_find() returns with db_mtx held */ 1768 db = dbuf_find(dn, level, blkid); 1769 1770 if (db == NULL) { 1771 blkptr_t *bp = NULL; 1772 int err; 1773 1774 ASSERT3P(parent, ==, NULL); 1775 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp); 1776 if (fail_sparse) { 1777 if (err == 0 && bp && BP_IS_HOLE(bp)) 1778 err = ENOENT; 1779 if (err) { 1780 if (parent) 1781 dbuf_rele(parent, NULL); 1782 return (err); 1783 } 1784 } 1785 if (err && err != ENOENT) 1786 return (err); 1787 db = dbuf_create(dn, level, blkid, parent, bp); 1788 } 1789 1790 if (db->db_buf && refcount_is_zero(&db->db_holds)) { 1791 arc_buf_add_ref(db->db_buf, db); 1792 if (db->db_buf->b_data == NULL) { 1793 dbuf_clear(db); 1794 if (parent) { 1795 dbuf_rele(parent, NULL); 1796 parent = NULL; 1797 } 1798 goto top; 1799 } 1800 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data); 1801 } 1802 1803 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf)); 1804 1805 /* 1806 * If this buffer is currently syncing out, and we are are 1807 * still referencing it from db_data, we need to make a copy 1808 * of it in case we decide we want to dirty it again in this txg. 1809 */ 1810 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1811 dn->dn_object != DMU_META_DNODE_OBJECT && 1812 db->db_state == DB_CACHED && db->db_data_pending) { 1813 dbuf_dirty_record_t *dr = db->db_data_pending; 1814 1815 if (dr->dt.dl.dr_data == db->db_buf) { 1816 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 1817 1818 dbuf_set_data(db, 1819 arc_buf_alloc(db->db_dnode->dn_objset->os_spa, 1820 db->db.db_size, db, type)); 1821 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data, 1822 db->db.db_size); 1823 } 1824 } 1825 1826 (void) refcount_add(&db->db_holds, tag); 1827 dbuf_update_data(db); 1828 DBUF_VERIFY(db); 1829 mutex_exit(&db->db_mtx); 1830 1831 /* NOTE: we can't rele the parent until after we drop the db_mtx */ 1832 if (parent) 1833 dbuf_rele(parent, NULL); 1834 1835 ASSERT3P(db->db_dnode, ==, dn); 1836 ASSERT3U(db->db_blkid, ==, blkid); 1837 ASSERT3U(db->db_level, ==, level); 1838 *dbp = db; 1839 1840 return (0); 1841 } 1842 1843 dmu_buf_impl_t * 1844 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag) 1845 { 1846 dmu_buf_impl_t *db; 1847 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db); 1848 return (err ? NULL : db); 1849 } 1850 1851 dmu_buf_impl_t * 1852 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag) 1853 { 1854 dmu_buf_impl_t *db; 1855 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db); 1856 return (err ? NULL : db); 1857 } 1858 1859 void 1860 dbuf_create_bonus(dnode_t *dn) 1861 { 1862 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 1863 1864 ASSERT(dn->dn_bonus == NULL); 1865 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL); 1866 } 1867 1868 int 1869 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx) 1870 { 1871 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1872 if (db->db_blkid != DMU_SPILL_BLKID) 1873 return (ENOTSUP); 1874 if (blksz == 0) 1875 blksz = SPA_MINBLOCKSIZE; 1876 if (blksz > SPA_MAXBLOCKSIZE) 1877 blksz = SPA_MAXBLOCKSIZE; 1878 else 1879 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE); 1880 1881 rw_enter(&db->db_dnode->dn_struct_rwlock, RW_WRITER); 1882 dbuf_new_size(db, blksz, tx); 1883 rw_exit(&db->db_dnode->dn_struct_rwlock); 1884 1885 return (0); 1886 } 1887 1888 void 1889 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx) 1890 { 1891 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx); 1892 } 1893 1894 #pragma weak dmu_buf_add_ref = dbuf_add_ref 1895 void 1896 dbuf_add_ref(dmu_buf_impl_t *db, void *tag) 1897 { 1898 int64_t holds = refcount_add(&db->db_holds, tag); 1899 ASSERT(holds > 1); 1900 } 1901 1902 #pragma weak dmu_buf_rele = dbuf_rele 1903 void 1904 dbuf_rele(dmu_buf_impl_t *db, void *tag) 1905 { 1906 mutex_enter(&db->db_mtx); 1907 dbuf_rele_and_unlock(db, tag); 1908 } 1909 1910 /* 1911 * dbuf_rele() for an already-locked dbuf. This is necessary to allow 1912 * db_dirtycnt and db_holds to be updated atomically. 1913 */ 1914 void 1915 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) 1916 { 1917 int64_t holds; 1918 1919 ASSERT(MUTEX_HELD(&db->db_mtx)); 1920 DBUF_VERIFY(db); 1921 1922 holds = refcount_remove(&db->db_holds, tag); 1923 ASSERT(holds >= 0); 1924 1925 /* 1926 * We can't freeze indirects if there is a possibility that they 1927 * may be modified in the current syncing context. 1928 */ 1929 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0)) 1930 arc_buf_freeze(db->db_buf); 1931 1932 if (holds == db->db_dirtycnt && 1933 db->db_level == 0 && db->db_immediate_evict) 1934 dbuf_evict_user(db); 1935 1936 if (holds == 0) { 1937 if (db->db_blkid == DMU_BONUS_BLKID) { 1938 mutex_exit(&db->db_mtx); 1939 dnode_rele(db->db_dnode, db); 1940 } else if (db->db_buf == NULL) { 1941 /* 1942 * This is a special case: we never associated this 1943 * dbuf with any data allocated from the ARC. 1944 */ 1945 ASSERT(db->db_state == DB_UNCACHED || 1946 db->db_state == DB_NOFILL); 1947 dbuf_evict(db); 1948 } else if (arc_released(db->db_buf)) { 1949 arc_buf_t *buf = db->db_buf; 1950 /* 1951 * This dbuf has anonymous data associated with it. 1952 */ 1953 dbuf_set_data(db, NULL); 1954 VERIFY(arc_buf_remove_ref(buf, db) == 1); 1955 dbuf_evict(db); 1956 } else { 1957 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 0); 1958 if (!DBUF_IS_CACHEABLE(db)) 1959 dbuf_clear(db); 1960 else 1961 mutex_exit(&db->db_mtx); 1962 } 1963 } else { 1964 mutex_exit(&db->db_mtx); 1965 } 1966 } 1967 1968 #pragma weak dmu_buf_refcount = dbuf_refcount 1969 uint64_t 1970 dbuf_refcount(dmu_buf_impl_t *db) 1971 { 1972 return (refcount_count(&db->db_holds)); 1973 } 1974 1975 void * 1976 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr, 1977 dmu_buf_evict_func_t *evict_func) 1978 { 1979 return (dmu_buf_update_user(db_fake, NULL, user_ptr, 1980 user_data_ptr_ptr, evict_func)); 1981 } 1982 1983 void * 1984 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr, 1985 dmu_buf_evict_func_t *evict_func) 1986 { 1987 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1988 1989 db->db_immediate_evict = TRUE; 1990 return (dmu_buf_update_user(db_fake, NULL, user_ptr, 1991 user_data_ptr_ptr, evict_func)); 1992 } 1993 1994 void * 1995 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr, 1996 void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func) 1997 { 1998 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1999 ASSERT(db->db_level == 0); 2000 2001 ASSERT((user_ptr == NULL) == (evict_func == NULL)); 2002 2003 mutex_enter(&db->db_mtx); 2004 2005 if (db->db_user_ptr == old_user_ptr) { 2006 db->db_user_ptr = user_ptr; 2007 db->db_user_data_ptr_ptr = user_data_ptr_ptr; 2008 db->db_evict_func = evict_func; 2009 2010 dbuf_update_data(db); 2011 } else { 2012 old_user_ptr = db->db_user_ptr; 2013 } 2014 2015 mutex_exit(&db->db_mtx); 2016 return (old_user_ptr); 2017 } 2018 2019 void * 2020 dmu_buf_get_user(dmu_buf_t *db_fake) 2021 { 2022 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2023 ASSERT(!refcount_is_zero(&db->db_holds)); 2024 2025 return (db->db_user_ptr); 2026 } 2027 2028 boolean_t 2029 dmu_buf_freeable(dmu_buf_t *dbuf) 2030 { 2031 boolean_t res = B_FALSE; 2032 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 2033 2034 if (db->db_blkptr) 2035 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset, 2036 db->db_blkptr->blk_birth); 2037 2038 return (res); 2039 } 2040 2041 static void 2042 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db) 2043 { 2044 /* ASSERT(dmu_tx_is_syncing(tx) */ 2045 ASSERT(MUTEX_HELD(&db->db_mtx)); 2046 2047 if (db->db_blkptr != NULL) 2048 return; 2049 2050 if (db->db_blkid == DMU_SPILL_BLKID) { 2051 db->db_blkptr = &dn->dn_phys->dn_spill; 2052 BP_ZERO(db->db_blkptr); 2053 return; 2054 } 2055 if (db->db_level == dn->dn_phys->dn_nlevels-1) { 2056 /* 2057 * This buffer was allocated at a time when there was 2058 * no available blkptrs from the dnode, or it was 2059 * inappropriate to hook it in (i.e., nlevels mis-match). 2060 */ 2061 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr); 2062 ASSERT(db->db_parent == NULL); 2063 db->db_parent = dn->dn_dbuf; 2064 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid]; 2065 DBUF_VERIFY(db); 2066 } else { 2067 dmu_buf_impl_t *parent = db->db_parent; 2068 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2069 2070 ASSERT(dn->dn_phys->dn_nlevels > 1); 2071 if (parent == NULL) { 2072 mutex_exit(&db->db_mtx); 2073 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2074 (void) dbuf_hold_impl(dn, db->db_level+1, 2075 db->db_blkid >> epbs, FALSE, db, &parent); 2076 rw_exit(&dn->dn_struct_rwlock); 2077 mutex_enter(&db->db_mtx); 2078 db->db_parent = parent; 2079 } 2080 db->db_blkptr = (blkptr_t *)parent->db.db_data + 2081 (db->db_blkid & ((1ULL << epbs) - 1)); 2082 DBUF_VERIFY(db); 2083 } 2084 } 2085 2086 static void 2087 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2088 { 2089 dmu_buf_impl_t *db = dr->dr_dbuf; 2090 dnode_t *dn = db->db_dnode; 2091 zio_t *zio; 2092 2093 ASSERT(dmu_tx_is_syncing(tx)); 2094 2095 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2096 2097 mutex_enter(&db->db_mtx); 2098 2099 ASSERT(db->db_level > 0); 2100 DBUF_VERIFY(db); 2101 2102 if (db->db_buf == NULL) { 2103 mutex_exit(&db->db_mtx); 2104 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); 2105 mutex_enter(&db->db_mtx); 2106 } 2107 ASSERT3U(db->db_state, ==, DB_CACHED); 2108 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2109 ASSERT(db->db_buf != NULL); 2110 2111 dbuf_check_blkptr(dn, db); 2112 2113 db->db_data_pending = dr; 2114 2115 mutex_exit(&db->db_mtx); 2116 dbuf_write(dr, db->db_buf, tx); 2117 2118 zio = dr->dr_zio; 2119 mutex_enter(&dr->dt.di.dr_mtx); 2120 dbuf_sync_list(&dr->dt.di.dr_children, tx); 2121 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2122 mutex_exit(&dr->dt.di.dr_mtx); 2123 zio_nowait(zio); 2124 } 2125 2126 static void 2127 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2128 { 2129 arc_buf_t **datap = &dr->dt.dl.dr_data; 2130 dmu_buf_impl_t *db = dr->dr_dbuf; 2131 dnode_t *dn = db->db_dnode; 2132 objset_t *os = dn->dn_objset; 2133 uint64_t txg = tx->tx_txg; 2134 2135 ASSERT(dmu_tx_is_syncing(tx)); 2136 2137 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2138 2139 mutex_enter(&db->db_mtx); 2140 /* 2141 * To be synced, we must be dirtied. But we 2142 * might have been freed after the dirty. 2143 */ 2144 if (db->db_state == DB_UNCACHED) { 2145 /* This buffer has been freed since it was dirtied */ 2146 ASSERT(db->db.db_data == NULL); 2147 } else if (db->db_state == DB_FILL) { 2148 /* This buffer was freed and is now being re-filled */ 2149 ASSERT(db->db.db_data != dr->dt.dl.dr_data); 2150 } else { 2151 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); 2152 } 2153 DBUF_VERIFY(db); 2154 2155 if (db->db_blkid == DMU_SPILL_BLKID) { 2156 mutex_enter(&dn->dn_mtx); 2157 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR; 2158 mutex_exit(&dn->dn_mtx); 2159 } 2160 2161 /* 2162 * If this is a bonus buffer, simply copy the bonus data into the 2163 * dnode. It will be written out when the dnode is synced (and it 2164 * will be synced, since it must have been dirty for dbuf_sync to 2165 * be called). 2166 */ 2167 if (db->db_blkid == DMU_BONUS_BLKID) { 2168 dbuf_dirty_record_t **drp; 2169 2170 ASSERT(*datap != NULL); 2171 ASSERT3U(db->db_level, ==, 0); 2172 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN); 2173 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen); 2174 if (*datap != db->db.db_data) { 2175 zio_buf_free(*datap, DN_MAX_BONUSLEN); 2176 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 2177 } 2178 db->db_data_pending = NULL; 2179 drp = &db->db_last_dirty; 2180 while (*drp != dr) 2181 drp = &(*drp)->dr_next; 2182 ASSERT(dr->dr_next == NULL); 2183 ASSERT(dr->dr_dbuf == db); 2184 *drp = dr->dr_next; 2185 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2186 ASSERT(db->db_dirtycnt > 0); 2187 db->db_dirtycnt -= 1; 2188 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2189 return; 2190 } 2191 2192 /* 2193 * This function may have dropped the db_mtx lock allowing a dmu_sync 2194 * operation to sneak in. As a result, we need to ensure that we 2195 * don't check the dr_override_state until we have returned from 2196 * dbuf_check_blkptr. 2197 */ 2198 dbuf_check_blkptr(dn, db); 2199 2200 /* 2201 * If this buffer is in the middle of an immdiate write, 2202 * wait for the synchronous IO to complete. 2203 */ 2204 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) { 2205 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); 2206 cv_wait(&db->db_changed, &db->db_mtx); 2207 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN); 2208 } 2209 2210 if (db->db_state != DB_NOFILL && 2211 dn->dn_object != DMU_META_DNODE_OBJECT && 2212 refcount_count(&db->db_holds) > 1 && 2213 dr->dt.dl.dr_override_state != DR_OVERRIDDEN && 2214 *datap == db->db_buf) { 2215 /* 2216 * If this buffer is currently "in use" (i.e., there 2217 * are active holds and db_data still references it), 2218 * then make a copy before we start the write so that 2219 * any modifications from the open txg will not leak 2220 * into this write. 2221 * 2222 * NOTE: this copy does not need to be made for 2223 * objects only modified in the syncing context (e.g. 2224 * DNONE_DNODE blocks). 2225 */ 2226 int blksz = arc_buf_size(*datap); 2227 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2228 *datap = arc_buf_alloc(os->os_spa, blksz, db, type); 2229 bcopy(db->db.db_data, (*datap)->b_data, blksz); 2230 } 2231 db->db_data_pending = dr; 2232 2233 mutex_exit(&db->db_mtx); 2234 2235 dbuf_write(dr, *datap, tx); 2236 2237 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2238 if (dn->dn_object == DMU_META_DNODE_OBJECT) 2239 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr); 2240 else 2241 zio_nowait(dr->dr_zio); 2242 } 2243 2244 void 2245 dbuf_sync_list(list_t *list, dmu_tx_t *tx) 2246 { 2247 dbuf_dirty_record_t *dr; 2248 2249 while (dr = list_head(list)) { 2250 if (dr->dr_zio != NULL) { 2251 /* 2252 * If we find an already initialized zio then we 2253 * are processing the meta-dnode, and we have finished. 2254 * The dbufs for all dnodes are put back on the list 2255 * during processing, so that we can zio_wait() 2256 * these IOs after initiating all child IOs. 2257 */ 2258 ASSERT3U(dr->dr_dbuf->db.db_object, ==, 2259 DMU_META_DNODE_OBJECT); 2260 break; 2261 } 2262 list_remove(list, dr); 2263 if (dr->dr_dbuf->db_level > 0) 2264 dbuf_sync_indirect(dr, tx); 2265 else 2266 dbuf_sync_leaf(dr, tx); 2267 } 2268 } 2269 2270 /* ARGSUSED */ 2271 static void 2272 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb) 2273 { 2274 dmu_buf_impl_t *db = vdb; 2275 blkptr_t *bp = zio->io_bp; 2276 blkptr_t *bp_orig = &zio->io_bp_orig; 2277 dnode_t *dn = db->db_dnode; 2278 spa_t *spa = zio->io_spa; 2279 int64_t delta; 2280 uint64_t fill = 0; 2281 int i; 2282 2283 ASSERT(db->db_blkptr == bp); 2284 2285 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig); 2286 dnode_diduse_space(dn, delta - zio->io_prev_space_delta); 2287 zio->io_prev_space_delta = delta; 2288 2289 if (BP_IS_HOLE(bp)) { 2290 ASSERT(bp->blk_fill == 0); 2291 return; 2292 } 2293 2294 ASSERT((db->db_blkid != DMU_SPILL_BLKID && 2295 BP_GET_TYPE(bp) == dn->dn_type) || 2296 (db->db_blkid == DMU_SPILL_BLKID && 2297 BP_GET_TYPE(bp) == dn->dn_bonustype)); 2298 ASSERT(BP_GET_LEVEL(bp) == db->db_level); 2299 2300 mutex_enter(&db->db_mtx); 2301 2302 #ifdef ZFS_DEBUG 2303 if (db->db_blkid == DMU_SPILL_BLKID) { 2304 dnode_t *dn = db->db_dnode; 2305 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2306 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2307 db->db_blkptr == &dn->dn_phys->dn_spill); 2308 } 2309 #endif 2310 2311 if (db->db_level == 0) { 2312 mutex_enter(&dn->dn_mtx); 2313 if (db->db_blkid > dn->dn_phys->dn_maxblkid && 2314 db->db_blkid != DMU_SPILL_BLKID) 2315 dn->dn_phys->dn_maxblkid = db->db_blkid; 2316 mutex_exit(&dn->dn_mtx); 2317 2318 if (dn->dn_type == DMU_OT_DNODE) { 2319 dnode_phys_t *dnp = db->db.db_data; 2320 for (i = db->db.db_size >> DNODE_SHIFT; i > 0; 2321 i--, dnp++) { 2322 if (dnp->dn_type != DMU_OT_NONE) 2323 fill++; 2324 } 2325 } else { 2326 fill = 1; 2327 } 2328 } else { 2329 blkptr_t *ibp = db->db.db_data; 2330 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2331 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) { 2332 if (BP_IS_HOLE(ibp)) 2333 continue; 2334 fill += ibp->blk_fill; 2335 } 2336 } 2337 2338 bp->blk_fill = fill; 2339 2340 mutex_exit(&db->db_mtx); 2341 } 2342 2343 /* ARGSUSED */ 2344 static void 2345 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb) 2346 { 2347 dmu_buf_impl_t *db = vdb; 2348 blkptr_t *bp = zio->io_bp; 2349 blkptr_t *bp_orig = &zio->io_bp_orig; 2350 dnode_t *dn = db->db_dnode; 2351 objset_t *os = dn->dn_objset; 2352 uint64_t txg = zio->io_txg; 2353 dbuf_dirty_record_t **drp, *dr; 2354 2355 ASSERT3U(zio->io_error, ==, 0); 2356 ASSERT(db->db_blkptr == bp); 2357 2358 if (zio->io_flags & ZIO_FLAG_IO_REWRITE) { 2359 ASSERT(BP_EQUAL(bp, bp_orig)); 2360 } else { 2361 dsl_dataset_t *ds = os->os_dsl_dataset; 2362 dmu_tx_t *tx = os->os_synctx; 2363 2364 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE); 2365 dsl_dataset_block_born(ds, bp, tx); 2366 } 2367 2368 mutex_enter(&db->db_mtx); 2369 2370 DBUF_VERIFY(db); 2371 2372 drp = &db->db_last_dirty; 2373 while ((dr = *drp) != db->db_data_pending) 2374 drp = &dr->dr_next; 2375 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2376 ASSERT(dr->dr_txg == txg); 2377 ASSERT(dr->dr_dbuf == db); 2378 ASSERT(dr->dr_next == NULL); 2379 *drp = dr->dr_next; 2380 2381 #ifdef ZFS_DEBUG 2382 if (db->db_blkid == DMU_SPILL_BLKID) { 2383 dnode_t *dn = db->db_dnode; 2384 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2385 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2386 db->db_blkptr == &dn->dn_phys->dn_spill); 2387 } 2388 #endif 2389 2390 if (db->db_level == 0) { 2391 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 2392 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN); 2393 if (db->db_state != DB_NOFILL) { 2394 if (dr->dt.dl.dr_data != db->db_buf) 2395 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 2396 db) == 1); 2397 else if (!arc_released(db->db_buf)) 2398 arc_set_callback(db->db_buf, dbuf_do_evict, db); 2399 } 2400 } else { 2401 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2402 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2403 if (!BP_IS_HOLE(db->db_blkptr)) { 2404 int epbs = 2405 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2406 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, 2407 db->db.db_size); 2408 ASSERT3U(dn->dn_phys->dn_maxblkid 2409 >> (db->db_level * epbs), >=, db->db_blkid); 2410 arc_set_callback(db->db_buf, dbuf_do_evict, db); 2411 } 2412 mutex_destroy(&dr->dt.di.dr_mtx); 2413 list_destroy(&dr->dt.di.dr_children); 2414 } 2415 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2416 2417 cv_broadcast(&db->db_changed); 2418 ASSERT(db->db_dirtycnt > 0); 2419 db->db_dirtycnt -= 1; 2420 db->db_data_pending = NULL; 2421 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2422 } 2423 2424 static void 2425 dbuf_write_nofill_ready(zio_t *zio) 2426 { 2427 dbuf_write_ready(zio, NULL, zio->io_private); 2428 } 2429 2430 static void 2431 dbuf_write_nofill_done(zio_t *zio) 2432 { 2433 dbuf_write_done(zio, NULL, zio->io_private); 2434 } 2435 2436 static void 2437 dbuf_write_override_ready(zio_t *zio) 2438 { 2439 dbuf_dirty_record_t *dr = zio->io_private; 2440 dmu_buf_impl_t *db = dr->dr_dbuf; 2441 2442 dbuf_write_ready(zio, NULL, db); 2443 } 2444 2445 static void 2446 dbuf_write_override_done(zio_t *zio) 2447 { 2448 dbuf_dirty_record_t *dr = zio->io_private; 2449 dmu_buf_impl_t *db = dr->dr_dbuf; 2450 blkptr_t *obp = &dr->dt.dl.dr_overridden_by; 2451 2452 mutex_enter(&db->db_mtx); 2453 if (!BP_EQUAL(zio->io_bp, obp)) { 2454 if (!BP_IS_HOLE(obp)) 2455 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp); 2456 arc_release(dr->dt.dl.dr_data, db); 2457 } 2458 mutex_exit(&db->db_mtx); 2459 2460 dbuf_write_done(zio, NULL, db); 2461 } 2462 2463 static void 2464 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) 2465 { 2466 dmu_buf_impl_t *db = dr->dr_dbuf; 2467 dnode_t *dn = db->db_dnode; 2468 objset_t *os = dn->dn_objset; 2469 dmu_buf_impl_t *parent = db->db_parent; 2470 uint64_t txg = tx->tx_txg; 2471 zbookmark_t zb; 2472 zio_prop_t zp; 2473 zio_t *zio; 2474 int wp_flag = 0; 2475 2476 if (db->db_state != DB_NOFILL) { 2477 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) { 2478 /* 2479 * Private object buffers are released here rather 2480 * than in dbuf_dirty() since they are only modified 2481 * in the syncing context and we don't want the 2482 * overhead of making multiple copies of the data. 2483 */ 2484 if (BP_IS_HOLE(db->db_blkptr)) { 2485 arc_buf_thaw(data); 2486 } else { 2487 dbuf_release_bp(db); 2488 } 2489 } 2490 } 2491 2492 if (parent != dn->dn_dbuf) { 2493 ASSERT(parent && parent->db_data_pending); 2494 ASSERT(db->db_level == parent->db_level-1); 2495 ASSERT(arc_released(parent->db_buf)); 2496 zio = parent->db_data_pending->dr_zio; 2497 } else { 2498 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && 2499 db->db_blkid != DMU_SPILL_BLKID) || 2500 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); 2501 if (db->db_blkid != DMU_SPILL_BLKID) 2502 ASSERT3P(db->db_blkptr, ==, 2503 &dn->dn_phys->dn_blkptr[db->db_blkid]); 2504 zio = dn->dn_zio; 2505 } 2506 2507 ASSERT(db->db_level == 0 || data == db->db_buf); 2508 ASSERT3U(db->db_blkptr->blk_birth, <=, txg); 2509 ASSERT(zio); 2510 2511 SET_BOOKMARK(&zb, os->os_dsl_dataset ? 2512 os->os_dsl_dataset->ds_object : DMU_META_OBJSET, 2513 db->db.db_object, db->db_level, db->db_blkid); 2514 2515 if (db->db_blkid == DMU_SPILL_BLKID) 2516 wp_flag = WP_SPILL; 2517 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0; 2518 2519 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp); 2520 2521 if (db->db_level == 0 && dr->dt.dl.dr_override_state == DR_OVERRIDDEN) { 2522 ASSERT(db->db_state != DB_NOFILL); 2523 dr->dr_zio = zio_write(zio, os->os_spa, txg, 2524 db->db_blkptr, data->b_data, arc_buf_size(data), &zp, 2525 dbuf_write_override_ready, dbuf_write_override_done, dr, 2526 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 2527 mutex_enter(&db->db_mtx); 2528 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 2529 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by, 2530 dr->dt.dl.dr_copies); 2531 mutex_exit(&db->db_mtx); 2532 } else if (db->db_state == DB_NOFILL) { 2533 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF); 2534 dr->dr_zio = zio_write(zio, os->os_spa, txg, 2535 db->db_blkptr, NULL, db->db.db_size, &zp, 2536 dbuf_write_nofill_ready, dbuf_write_nofill_done, db, 2537 ZIO_PRIORITY_ASYNC_WRITE, 2538 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb); 2539 } else { 2540 ASSERT(arc_released(data)); 2541 dr->dr_zio = arc_write(zio, os->os_spa, txg, 2542 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), &zp, 2543 dbuf_write_ready, dbuf_write_done, db, 2544 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 2545 } 2546 } 2547