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 parent_held = TRUE; 1172 } 1173 if (drop_struct_lock) 1174 rw_exit(&dn->dn_struct_rwlock); 1175 ASSERT3U(db->db_level+1, ==, parent->db_level); 1176 di = dbuf_dirty(parent, tx); 1177 if (parent_held) 1178 dbuf_rele(parent, FTAG); 1179 1180 mutex_enter(&db->db_mtx); 1181 /* possible race with dbuf_undirty() */ 1182 if (db->db_last_dirty == dr || 1183 dn->dn_object == DMU_META_DNODE_OBJECT) { 1184 mutex_enter(&di->dt.di.dr_mtx); 1185 ASSERT3U(di->dr_txg, ==, tx->tx_txg); 1186 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1187 list_insert_tail(&di->dt.di.dr_children, dr); 1188 mutex_exit(&di->dt.di.dr_mtx); 1189 dr->dr_parent = di; 1190 } 1191 mutex_exit(&db->db_mtx); 1192 } else { 1193 ASSERT(db->db_level+1 == dn->dn_nlevels); 1194 ASSERT(db->db_blkid < dn->dn_nblkptr); 1195 ASSERT(db->db_parent == NULL || 1196 db->db_parent == db->db_dnode->dn_dbuf); 1197 mutex_enter(&dn->dn_mtx); 1198 ASSERT(!list_link_active(&dr->dr_dirty_node)); 1199 list_insert_tail(&dn->dn_dirty_records[txgoff], dr); 1200 mutex_exit(&dn->dn_mtx); 1201 if (drop_struct_lock) 1202 rw_exit(&dn->dn_struct_rwlock); 1203 } 1204 1205 dnode_setdirty(dn, tx); 1206 return (dr); 1207 } 1208 1209 static int 1210 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1211 { 1212 dnode_t *dn = db->db_dnode; 1213 uint64_t txg = tx->tx_txg; 1214 dbuf_dirty_record_t *dr, **drp; 1215 1216 ASSERT(txg != 0); 1217 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1218 1219 mutex_enter(&db->db_mtx); 1220 /* 1221 * If this buffer is not dirty, we're done. 1222 */ 1223 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next) 1224 if (dr->dr_txg <= txg) 1225 break; 1226 if (dr == NULL || dr->dr_txg < txg) { 1227 mutex_exit(&db->db_mtx); 1228 return (0); 1229 } 1230 ASSERT(dr->dr_txg == txg); 1231 ASSERT(dr->dr_dbuf == db); 1232 1233 /* 1234 * If this buffer is currently held, we cannot undirty 1235 * it, since one of the current holders may be in the 1236 * middle of an update. Note that users of dbuf_undirty() 1237 * should not place a hold on the dbuf before the call. 1238 */ 1239 if (refcount_count(&db->db_holds) > db->db_dirtycnt) { 1240 mutex_exit(&db->db_mtx); 1241 /* Make sure we don't toss this buffer at sync phase */ 1242 mutex_enter(&dn->dn_mtx); 1243 dnode_clear_range(dn, db->db_blkid, 1, tx); 1244 mutex_exit(&dn->dn_mtx); 1245 return (0); 1246 } 1247 1248 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); 1249 1250 ASSERT(db->db.db_size != 0); 1251 1252 /* XXX would be nice to fix up dn_towrite_space[] */ 1253 1254 *drp = dr->dr_next; 1255 1256 if (dr->dr_parent) { 1257 mutex_enter(&dr->dr_parent->dt.di.dr_mtx); 1258 list_remove(&dr->dr_parent->dt.di.dr_children, dr); 1259 mutex_exit(&dr->dr_parent->dt.di.dr_mtx); 1260 } else if (db->db_level+1 == dn->dn_nlevels) { 1261 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf); 1262 mutex_enter(&dn->dn_mtx); 1263 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr); 1264 mutex_exit(&dn->dn_mtx); 1265 } 1266 1267 if (db->db_level == 0) { 1268 if (db->db_state != DB_NOFILL) { 1269 dbuf_unoverride(dr); 1270 1271 ASSERT(db->db_buf != NULL); 1272 ASSERT(dr->dt.dl.dr_data != NULL); 1273 if (dr->dt.dl.dr_data != db->db_buf) 1274 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 1275 db) == 1); 1276 } 1277 } else { 1278 ASSERT(db->db_buf != NULL); 1279 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 1280 mutex_destroy(&dr->dt.di.dr_mtx); 1281 list_destroy(&dr->dt.di.dr_children); 1282 } 1283 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 1284 1285 ASSERT(db->db_dirtycnt > 0); 1286 db->db_dirtycnt -= 1; 1287 1288 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) { 1289 arc_buf_t *buf = db->db_buf; 1290 1291 ASSERT(db->db_state == DB_NOFILL || arc_released(buf)); 1292 dbuf_set_data(db, NULL); 1293 VERIFY(arc_buf_remove_ref(buf, db) == 1); 1294 dbuf_evict(db); 1295 return (1); 1296 } 1297 1298 mutex_exit(&db->db_mtx); 1299 return (0); 1300 } 1301 1302 #pragma weak dmu_buf_will_dirty = dbuf_will_dirty 1303 void 1304 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) 1305 { 1306 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH; 1307 1308 ASSERT(tx->tx_txg != 0); 1309 ASSERT(!refcount_is_zero(&db->db_holds)); 1310 1311 if (RW_WRITE_HELD(&db->db_dnode->dn_struct_rwlock)) 1312 rf |= DB_RF_HAVESTRUCT; 1313 (void) dbuf_read(db, NULL, rf); 1314 (void) dbuf_dirty(db, tx); 1315 } 1316 1317 void 1318 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1319 { 1320 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1321 1322 db->db_state = DB_NOFILL; 1323 1324 dmu_buf_will_fill(db_fake, tx); 1325 } 1326 1327 void 1328 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) 1329 { 1330 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1331 1332 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1333 ASSERT(tx->tx_txg != 0); 1334 ASSERT(db->db_level == 0); 1335 ASSERT(!refcount_is_zero(&db->db_holds)); 1336 1337 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT || 1338 dmu_tx_private_ok(tx)); 1339 1340 dbuf_noread(db); 1341 (void) dbuf_dirty(db, tx); 1342 } 1343 1344 #pragma weak dmu_buf_fill_done = dbuf_fill_done 1345 /* ARGSUSED */ 1346 void 1347 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx) 1348 { 1349 mutex_enter(&db->db_mtx); 1350 DBUF_VERIFY(db); 1351 1352 if (db->db_state == DB_FILL) { 1353 if (db->db_level == 0 && db->db_freed_in_flight) { 1354 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1355 /* we were freed while filling */ 1356 /* XXX dbuf_undirty? */ 1357 bzero(db->db.db_data, db->db.db_size); 1358 db->db_freed_in_flight = FALSE; 1359 } 1360 db->db_state = DB_CACHED; 1361 cv_broadcast(&db->db_changed); 1362 } 1363 mutex_exit(&db->db_mtx); 1364 } 1365 1366 /* 1367 * Directly assign a provided arc buf to a given dbuf if it's not referenced 1368 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf. 1369 */ 1370 void 1371 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx) 1372 { 1373 ASSERT(!refcount_is_zero(&db->db_holds)); 1374 ASSERT(db->db_dnode->dn_object != DMU_META_DNODE_OBJECT); 1375 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 1376 ASSERT(db->db_level == 0); 1377 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA); 1378 ASSERT(buf != NULL); 1379 ASSERT(arc_buf_size(buf) == db->db.db_size); 1380 ASSERT(tx->tx_txg != 0); 1381 1382 arc_return_buf(buf, db); 1383 ASSERT(arc_released(buf)); 1384 1385 mutex_enter(&db->db_mtx); 1386 1387 while (db->db_state == DB_READ || db->db_state == DB_FILL) 1388 cv_wait(&db->db_changed, &db->db_mtx); 1389 1390 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED); 1391 1392 if (db->db_state == DB_CACHED && 1393 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) { 1394 mutex_exit(&db->db_mtx); 1395 (void) dbuf_dirty(db, tx); 1396 bcopy(buf->b_data, db->db.db_data, db->db.db_size); 1397 VERIFY(arc_buf_remove_ref(buf, db) == 1); 1398 xuio_stat_wbuf_copied(); 1399 return; 1400 } 1401 1402 xuio_stat_wbuf_nocopy(); 1403 if (db->db_state == DB_CACHED) { 1404 dbuf_dirty_record_t *dr = db->db_last_dirty; 1405 1406 ASSERT(db->db_buf != NULL); 1407 if (dr != NULL && dr->dr_txg == tx->tx_txg) { 1408 ASSERT(dr->dt.dl.dr_data == db->db_buf); 1409 if (!arc_released(db->db_buf)) { 1410 ASSERT(dr->dt.dl.dr_override_state == 1411 DR_OVERRIDDEN); 1412 arc_release(db->db_buf, db); 1413 } 1414 dr->dt.dl.dr_data = buf; 1415 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1); 1416 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) { 1417 arc_release(db->db_buf, db); 1418 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1); 1419 } 1420 db->db_buf = NULL; 1421 } 1422 ASSERT(db->db_buf == NULL); 1423 dbuf_set_data(db, buf); 1424 db->db_state = DB_FILL; 1425 mutex_exit(&db->db_mtx); 1426 (void) dbuf_dirty(db, tx); 1427 dbuf_fill_done(db, tx); 1428 } 1429 1430 /* 1431 * "Clear" the contents of this dbuf. This will mark the dbuf 1432 * EVICTING and clear *most* of its references. Unfortunetely, 1433 * when we are not holding the dn_dbufs_mtx, we can't clear the 1434 * entry in the dn_dbufs list. We have to wait until dbuf_destroy() 1435 * in this case. For callers from the DMU we will usually see: 1436 * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy() 1437 * For the arc callback, we will usually see: 1438 * dbuf_do_evict()->dbuf_clear();dbuf_destroy() 1439 * Sometimes, though, we will get a mix of these two: 1440 * DMU: dbuf_clear()->arc_buf_evict() 1441 * ARC: dbuf_do_evict()->dbuf_destroy() 1442 */ 1443 void 1444 dbuf_clear(dmu_buf_impl_t *db) 1445 { 1446 dnode_t *dn = db->db_dnode; 1447 dmu_buf_impl_t *parent = db->db_parent; 1448 dmu_buf_impl_t *dndb = dn->dn_dbuf; 1449 int dbuf_gone = FALSE; 1450 1451 ASSERT(MUTEX_HELD(&db->db_mtx)); 1452 ASSERT(refcount_is_zero(&db->db_holds)); 1453 1454 dbuf_evict_user(db); 1455 1456 if (db->db_state == DB_CACHED) { 1457 ASSERT(db->db.db_data != NULL); 1458 if (db->db_blkid == DMU_BONUS_BLKID) { 1459 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN); 1460 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 1461 } 1462 db->db.db_data = NULL; 1463 db->db_state = DB_UNCACHED; 1464 } 1465 1466 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL); 1467 ASSERT(db->db_data_pending == NULL); 1468 1469 db->db_state = DB_EVICTING; 1470 db->db_blkptr = NULL; 1471 1472 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) { 1473 list_remove(&dn->dn_dbufs, db); 1474 dnode_rele(dn, db); 1475 db->db_dnode = NULL; 1476 } 1477 1478 if (db->db_buf) 1479 dbuf_gone = arc_buf_evict(db->db_buf); 1480 1481 if (!dbuf_gone) 1482 mutex_exit(&db->db_mtx); 1483 1484 /* 1485 * If this dbuf is referened from an indirect dbuf, 1486 * decrement the ref count on the indirect dbuf. 1487 */ 1488 if (parent && parent != dndb) 1489 dbuf_rele(parent, db); 1490 } 1491 1492 static int 1493 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, 1494 dmu_buf_impl_t **parentp, blkptr_t **bpp) 1495 { 1496 int nlevels, epbs; 1497 1498 *parentp = NULL; 1499 *bpp = NULL; 1500 1501 ASSERT(blkid != DMU_BONUS_BLKID); 1502 1503 if (blkid == DMU_SPILL_BLKID) { 1504 mutex_enter(&dn->dn_mtx); 1505 if (dn->dn_have_spill && 1506 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) 1507 *bpp = &dn->dn_phys->dn_spill; 1508 else 1509 *bpp = NULL; 1510 dbuf_add_ref(dn->dn_dbuf, NULL); 1511 *parentp = dn->dn_dbuf; 1512 mutex_exit(&dn->dn_mtx); 1513 return (0); 1514 } 1515 1516 if (dn->dn_phys->dn_nlevels == 0) 1517 nlevels = 1; 1518 else 1519 nlevels = dn->dn_phys->dn_nlevels; 1520 1521 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1522 1523 ASSERT3U(level * epbs, <, 64); 1524 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1525 if (level >= nlevels || 1526 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) { 1527 /* the buffer has no parent yet */ 1528 return (ENOENT); 1529 } else if (level < nlevels-1) { 1530 /* this block is referenced from an indirect block */ 1531 int err = dbuf_hold_impl(dn, level+1, 1532 blkid >> epbs, fail_sparse, NULL, parentp); 1533 if (err) 1534 return (err); 1535 err = dbuf_read(*parentp, NULL, 1536 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL)); 1537 if (err) { 1538 dbuf_rele(*parentp, NULL); 1539 *parentp = NULL; 1540 return (err); 1541 } 1542 *bpp = ((blkptr_t *)(*parentp)->db.db_data) + 1543 (blkid & ((1ULL << epbs) - 1)); 1544 return (0); 1545 } else { 1546 /* the block is referenced from the dnode */ 1547 ASSERT3U(level, ==, nlevels-1); 1548 ASSERT(dn->dn_phys->dn_nblkptr == 0 || 1549 blkid < dn->dn_phys->dn_nblkptr); 1550 if (dn->dn_dbuf) { 1551 dbuf_add_ref(dn->dn_dbuf, NULL); 1552 *parentp = dn->dn_dbuf; 1553 } 1554 *bpp = &dn->dn_phys->dn_blkptr[blkid]; 1555 return (0); 1556 } 1557 } 1558 1559 static dmu_buf_impl_t * 1560 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid, 1561 dmu_buf_impl_t *parent, blkptr_t *blkptr) 1562 { 1563 objset_t *os = dn->dn_objset; 1564 dmu_buf_impl_t *db, *odb; 1565 1566 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1567 ASSERT(dn->dn_type != DMU_OT_NONE); 1568 1569 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP); 1570 1571 db->db_objset = os; 1572 db->db.db_object = dn->dn_object; 1573 db->db_level = level; 1574 db->db_blkid = blkid; 1575 db->db_last_dirty = NULL; 1576 db->db_dirtycnt = 0; 1577 db->db_dnode = dn; 1578 db->db_parent = parent; 1579 db->db_blkptr = blkptr; 1580 1581 db->db_user_ptr = NULL; 1582 db->db_user_data_ptr_ptr = NULL; 1583 db->db_evict_func = NULL; 1584 db->db_immediate_evict = 0; 1585 db->db_freed_in_flight = 0; 1586 1587 if (blkid == DMU_BONUS_BLKID) { 1588 ASSERT3P(parent, ==, dn->dn_dbuf); 1589 db->db.db_size = DN_MAX_BONUSLEN - 1590 (dn->dn_nblkptr-1) * sizeof (blkptr_t); 1591 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); 1592 db->db.db_offset = DMU_BONUS_BLKID; 1593 db->db_state = DB_UNCACHED; 1594 /* the bonus dbuf is not placed in the hash table */ 1595 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1596 return (db); 1597 } else if (blkid == DMU_SPILL_BLKID) { 1598 db->db.db_size = (blkptr != NULL) ? 1599 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE; 1600 db->db.db_offset = 0; 1601 } else { 1602 int blocksize = 1603 db->db_level ? 1<<dn->dn_indblkshift : dn->dn_datablksz; 1604 db->db.db_size = blocksize; 1605 db->db.db_offset = db->db_blkid * blocksize; 1606 } 1607 1608 /* 1609 * Hold the dn_dbufs_mtx while we get the new dbuf 1610 * in the hash table *and* added to the dbufs list. 1611 * This prevents a possible deadlock with someone 1612 * trying to look up this dbuf before its added to the 1613 * dn_dbufs list. 1614 */ 1615 mutex_enter(&dn->dn_dbufs_mtx); 1616 db->db_state = DB_EVICTING; 1617 if ((odb = dbuf_hash_insert(db)) != NULL) { 1618 /* someone else inserted it first */ 1619 kmem_cache_free(dbuf_cache, db); 1620 mutex_exit(&dn->dn_dbufs_mtx); 1621 return (odb); 1622 } 1623 list_insert_head(&dn->dn_dbufs, db); 1624 db->db_state = DB_UNCACHED; 1625 mutex_exit(&dn->dn_dbufs_mtx); 1626 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1627 1628 if (parent && parent != dn->dn_dbuf) 1629 dbuf_add_ref(parent, db); 1630 1631 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || 1632 refcount_count(&dn->dn_holds) > 0); 1633 (void) refcount_add(&dn->dn_holds, db); 1634 1635 dprintf_dbuf(db, "db=%p\n", db); 1636 1637 return (db); 1638 } 1639 1640 static int 1641 dbuf_do_evict(void *private) 1642 { 1643 arc_buf_t *buf = private; 1644 dmu_buf_impl_t *db = buf->b_private; 1645 1646 if (!MUTEX_HELD(&db->db_mtx)) 1647 mutex_enter(&db->db_mtx); 1648 1649 ASSERT(refcount_is_zero(&db->db_holds)); 1650 1651 if (db->db_state != DB_EVICTING) { 1652 ASSERT(db->db_state == DB_CACHED); 1653 DBUF_VERIFY(db); 1654 db->db_buf = NULL; 1655 dbuf_evict(db); 1656 } else { 1657 mutex_exit(&db->db_mtx); 1658 dbuf_destroy(db); 1659 } 1660 return (0); 1661 } 1662 1663 static void 1664 dbuf_destroy(dmu_buf_impl_t *db) 1665 { 1666 ASSERT(refcount_is_zero(&db->db_holds)); 1667 1668 if (db->db_blkid != DMU_BONUS_BLKID) { 1669 /* 1670 * If this dbuf is still on the dn_dbufs list, 1671 * remove it from that list. 1672 */ 1673 if (db->db_dnode) { 1674 dnode_t *dn = db->db_dnode; 1675 1676 mutex_enter(&dn->dn_dbufs_mtx); 1677 list_remove(&dn->dn_dbufs, db); 1678 mutex_exit(&dn->dn_dbufs_mtx); 1679 1680 dnode_rele(dn, db); 1681 db->db_dnode = NULL; 1682 } 1683 dbuf_hash_remove(db); 1684 } 1685 db->db_parent = NULL; 1686 db->db_buf = NULL; 1687 1688 ASSERT(!list_link_active(&db->db_link)); 1689 ASSERT(db->db.db_data == NULL); 1690 ASSERT(db->db_hash_next == NULL); 1691 ASSERT(db->db_blkptr == NULL); 1692 ASSERT(db->db_data_pending == NULL); 1693 1694 kmem_cache_free(dbuf_cache, db); 1695 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER); 1696 } 1697 1698 void 1699 dbuf_prefetch(dnode_t *dn, uint64_t blkid) 1700 { 1701 dmu_buf_impl_t *db = NULL; 1702 blkptr_t *bp = NULL; 1703 1704 ASSERT(blkid != DMU_BONUS_BLKID); 1705 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1706 1707 if (dnode_block_freed(dn, blkid)) 1708 return; 1709 1710 /* dbuf_find() returns with db_mtx held */ 1711 if (db = dbuf_find(dn, 0, blkid)) { 1712 if (refcount_count(&db->db_holds) > 0) { 1713 /* 1714 * This dbuf is active. We assume that it is 1715 * already CACHED, or else about to be either 1716 * read or filled. 1717 */ 1718 mutex_exit(&db->db_mtx); 1719 return; 1720 } 1721 mutex_exit(&db->db_mtx); 1722 db = NULL; 1723 } 1724 1725 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) { 1726 if (bp && !BP_IS_HOLE(bp)) { 1727 arc_buf_t *pbuf; 1728 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; 1729 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH; 1730 zbookmark_t zb; 1731 1732 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET, 1733 dn->dn_object, 0, blkid); 1734 1735 if (db) 1736 pbuf = db->db_buf; 1737 else 1738 pbuf = dn->dn_objset->os_phys_buf; 1739 1740 (void) dsl_read(NULL, dn->dn_objset->os_spa, 1741 bp, pbuf, NULL, NULL, ZIO_PRIORITY_ASYNC_READ, 1742 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, 1743 &aflags, &zb); 1744 } 1745 if (db) 1746 dbuf_rele(db, NULL); 1747 } 1748 } 1749 1750 /* 1751 * Returns with db_holds incremented, and db_mtx not held. 1752 * Note: dn_struct_rwlock must be held. 1753 */ 1754 int 1755 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse, 1756 void *tag, dmu_buf_impl_t **dbp) 1757 { 1758 dmu_buf_impl_t *db, *parent = NULL; 1759 1760 ASSERT(blkid != DMU_BONUS_BLKID); 1761 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); 1762 ASSERT3U(dn->dn_nlevels, >, level); 1763 1764 *dbp = NULL; 1765 top: 1766 /* dbuf_find() returns with db_mtx held */ 1767 db = dbuf_find(dn, level, blkid); 1768 1769 if (db == NULL) { 1770 blkptr_t *bp = NULL; 1771 int err; 1772 1773 ASSERT3P(parent, ==, NULL); 1774 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp); 1775 if (fail_sparse) { 1776 if (err == 0 && bp && BP_IS_HOLE(bp)) 1777 err = ENOENT; 1778 if (err) { 1779 if (parent) 1780 dbuf_rele(parent, NULL); 1781 return (err); 1782 } 1783 } 1784 if (err && err != ENOENT) 1785 return (err); 1786 db = dbuf_create(dn, level, blkid, parent, bp); 1787 } 1788 1789 if (db->db_buf && refcount_is_zero(&db->db_holds)) { 1790 arc_buf_add_ref(db->db_buf, db); 1791 if (db->db_buf->b_data == NULL) { 1792 dbuf_clear(db); 1793 if (parent) { 1794 dbuf_rele(parent, NULL); 1795 parent = NULL; 1796 } 1797 goto top; 1798 } 1799 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data); 1800 } 1801 1802 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf)); 1803 1804 /* 1805 * If this buffer is currently syncing out, and we are are 1806 * still referencing it from db_data, we need to make a copy 1807 * of it in case we decide we want to dirty it again in this txg. 1808 */ 1809 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && 1810 dn->dn_object != DMU_META_DNODE_OBJECT && 1811 db->db_state == DB_CACHED && db->db_data_pending) { 1812 dbuf_dirty_record_t *dr = db->db_data_pending; 1813 1814 if (dr->dt.dl.dr_data == db->db_buf) { 1815 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 1816 1817 dbuf_set_data(db, 1818 arc_buf_alloc(db->db_dnode->dn_objset->os_spa, 1819 db->db.db_size, db, type)); 1820 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data, 1821 db->db.db_size); 1822 } 1823 } 1824 1825 (void) refcount_add(&db->db_holds, tag); 1826 dbuf_update_data(db); 1827 DBUF_VERIFY(db); 1828 mutex_exit(&db->db_mtx); 1829 1830 /* NOTE: we can't rele the parent until after we drop the db_mtx */ 1831 if (parent) 1832 dbuf_rele(parent, NULL); 1833 1834 ASSERT3P(db->db_dnode, ==, dn); 1835 ASSERT3U(db->db_blkid, ==, blkid); 1836 ASSERT3U(db->db_level, ==, level); 1837 *dbp = db; 1838 1839 return (0); 1840 } 1841 1842 dmu_buf_impl_t * 1843 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag) 1844 { 1845 dmu_buf_impl_t *db; 1846 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db); 1847 return (err ? NULL : db); 1848 } 1849 1850 dmu_buf_impl_t * 1851 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag) 1852 { 1853 dmu_buf_impl_t *db; 1854 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db); 1855 return (err ? NULL : db); 1856 } 1857 1858 void 1859 dbuf_create_bonus(dnode_t *dn) 1860 { 1861 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 1862 1863 ASSERT(dn->dn_bonus == NULL); 1864 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL); 1865 } 1866 1867 int 1868 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx) 1869 { 1870 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1871 if (db->db_blkid != DMU_SPILL_BLKID) 1872 return (ENOTSUP); 1873 if (blksz == 0) 1874 blksz = SPA_MINBLOCKSIZE; 1875 if (blksz > SPA_MAXBLOCKSIZE) 1876 blksz = SPA_MAXBLOCKSIZE; 1877 else 1878 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE); 1879 1880 rw_enter(&db->db_dnode->dn_struct_rwlock, RW_WRITER); 1881 dbuf_new_size(db, blksz, tx); 1882 rw_exit(&db->db_dnode->dn_struct_rwlock); 1883 1884 return (0); 1885 } 1886 1887 void 1888 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx) 1889 { 1890 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx); 1891 } 1892 1893 #pragma weak dmu_buf_add_ref = dbuf_add_ref 1894 void 1895 dbuf_add_ref(dmu_buf_impl_t *db, void *tag) 1896 { 1897 int64_t holds = refcount_add(&db->db_holds, tag); 1898 ASSERT(holds > 1); 1899 } 1900 1901 #pragma weak dmu_buf_rele = dbuf_rele 1902 void 1903 dbuf_rele(dmu_buf_impl_t *db, void *tag) 1904 { 1905 mutex_enter(&db->db_mtx); 1906 dbuf_rele_and_unlock(db, tag); 1907 } 1908 1909 /* 1910 * dbuf_rele() for an already-locked dbuf. This is necessary to allow 1911 * db_dirtycnt and db_holds to be updated atomically. 1912 */ 1913 void 1914 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag) 1915 { 1916 int64_t holds; 1917 1918 ASSERT(MUTEX_HELD(&db->db_mtx)); 1919 DBUF_VERIFY(db); 1920 1921 holds = refcount_remove(&db->db_holds, tag); 1922 ASSERT(holds >= 0); 1923 1924 /* 1925 * We can't freeze indirects if there is a possibility that they 1926 * may be modified in the current syncing context. 1927 */ 1928 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0)) 1929 arc_buf_freeze(db->db_buf); 1930 1931 if (holds == db->db_dirtycnt && 1932 db->db_level == 0 && db->db_immediate_evict) 1933 dbuf_evict_user(db); 1934 1935 if (holds == 0) { 1936 if (db->db_blkid == DMU_BONUS_BLKID) { 1937 mutex_exit(&db->db_mtx); 1938 dnode_rele(db->db_dnode, db); 1939 } else if (db->db_buf == NULL) { 1940 /* 1941 * This is a special case: we never associated this 1942 * dbuf with any data allocated from the ARC. 1943 */ 1944 ASSERT(db->db_state == DB_UNCACHED || 1945 db->db_state == DB_NOFILL); 1946 dbuf_evict(db); 1947 } else if (arc_released(db->db_buf)) { 1948 arc_buf_t *buf = db->db_buf; 1949 /* 1950 * This dbuf has anonymous data associated with it. 1951 */ 1952 dbuf_set_data(db, NULL); 1953 VERIFY(arc_buf_remove_ref(buf, db) == 1); 1954 dbuf_evict(db); 1955 } else { 1956 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 0); 1957 if (!DBUF_IS_CACHEABLE(db)) 1958 dbuf_clear(db); 1959 else 1960 mutex_exit(&db->db_mtx); 1961 } 1962 } else { 1963 mutex_exit(&db->db_mtx); 1964 } 1965 } 1966 1967 #pragma weak dmu_buf_refcount = dbuf_refcount 1968 uint64_t 1969 dbuf_refcount(dmu_buf_impl_t *db) 1970 { 1971 return (refcount_count(&db->db_holds)); 1972 } 1973 1974 void * 1975 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr, 1976 dmu_buf_evict_func_t *evict_func) 1977 { 1978 return (dmu_buf_update_user(db_fake, NULL, user_ptr, 1979 user_data_ptr_ptr, evict_func)); 1980 } 1981 1982 void * 1983 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr, 1984 dmu_buf_evict_func_t *evict_func) 1985 { 1986 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1987 1988 db->db_immediate_evict = TRUE; 1989 return (dmu_buf_update_user(db_fake, NULL, user_ptr, 1990 user_data_ptr_ptr, evict_func)); 1991 } 1992 1993 void * 1994 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr, 1995 void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func) 1996 { 1997 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 1998 ASSERT(db->db_level == 0); 1999 2000 ASSERT((user_ptr == NULL) == (evict_func == NULL)); 2001 2002 mutex_enter(&db->db_mtx); 2003 2004 if (db->db_user_ptr == old_user_ptr) { 2005 db->db_user_ptr = user_ptr; 2006 db->db_user_data_ptr_ptr = user_data_ptr_ptr; 2007 db->db_evict_func = evict_func; 2008 2009 dbuf_update_data(db); 2010 } else { 2011 old_user_ptr = db->db_user_ptr; 2012 } 2013 2014 mutex_exit(&db->db_mtx); 2015 return (old_user_ptr); 2016 } 2017 2018 void * 2019 dmu_buf_get_user(dmu_buf_t *db_fake) 2020 { 2021 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; 2022 ASSERT(!refcount_is_zero(&db->db_holds)); 2023 2024 return (db->db_user_ptr); 2025 } 2026 2027 boolean_t 2028 dmu_buf_freeable(dmu_buf_t *dbuf) 2029 { 2030 boolean_t res = B_FALSE; 2031 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; 2032 2033 if (db->db_blkptr) 2034 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset, 2035 db->db_blkptr->blk_birth); 2036 2037 return (res); 2038 } 2039 2040 static void 2041 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db) 2042 { 2043 /* ASSERT(dmu_tx_is_syncing(tx) */ 2044 ASSERT(MUTEX_HELD(&db->db_mtx)); 2045 2046 if (db->db_blkptr != NULL) 2047 return; 2048 2049 if (db->db_blkid == DMU_SPILL_BLKID) { 2050 db->db_blkptr = &dn->dn_phys->dn_spill; 2051 BP_ZERO(db->db_blkptr); 2052 return; 2053 } 2054 if (db->db_level == dn->dn_phys->dn_nlevels-1) { 2055 /* 2056 * This buffer was allocated at a time when there was 2057 * no available blkptrs from the dnode, or it was 2058 * inappropriate to hook it in (i.e., nlevels mis-match). 2059 */ 2060 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr); 2061 ASSERT(db->db_parent == NULL); 2062 db->db_parent = dn->dn_dbuf; 2063 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid]; 2064 DBUF_VERIFY(db); 2065 } else { 2066 dmu_buf_impl_t *parent = db->db_parent; 2067 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2068 2069 ASSERT(dn->dn_phys->dn_nlevels > 1); 2070 if (parent == NULL) { 2071 mutex_exit(&db->db_mtx); 2072 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2073 (void) dbuf_hold_impl(dn, db->db_level+1, 2074 db->db_blkid >> epbs, FALSE, db, &parent); 2075 rw_exit(&dn->dn_struct_rwlock); 2076 mutex_enter(&db->db_mtx); 2077 db->db_parent = parent; 2078 } 2079 db->db_blkptr = (blkptr_t *)parent->db.db_data + 2080 (db->db_blkid & ((1ULL << epbs) - 1)); 2081 DBUF_VERIFY(db); 2082 } 2083 } 2084 2085 static void 2086 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2087 { 2088 dmu_buf_impl_t *db = dr->dr_dbuf; 2089 dnode_t *dn = db->db_dnode; 2090 zio_t *zio; 2091 2092 ASSERT(dmu_tx_is_syncing(tx)); 2093 2094 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2095 2096 mutex_enter(&db->db_mtx); 2097 2098 ASSERT(db->db_level > 0); 2099 DBUF_VERIFY(db); 2100 2101 if (db->db_buf == NULL) { 2102 mutex_exit(&db->db_mtx); 2103 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); 2104 mutex_enter(&db->db_mtx); 2105 } 2106 ASSERT3U(db->db_state, ==, DB_CACHED); 2107 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2108 ASSERT(db->db_buf != NULL); 2109 2110 dbuf_check_blkptr(dn, db); 2111 2112 db->db_data_pending = dr; 2113 2114 mutex_exit(&db->db_mtx); 2115 dbuf_write(dr, db->db_buf, tx); 2116 2117 zio = dr->dr_zio; 2118 mutex_enter(&dr->dt.di.dr_mtx); 2119 dbuf_sync_list(&dr->dt.di.dr_children, tx); 2120 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2121 mutex_exit(&dr->dt.di.dr_mtx); 2122 zio_nowait(zio); 2123 } 2124 2125 static void 2126 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) 2127 { 2128 arc_buf_t **datap = &dr->dt.dl.dr_data; 2129 dmu_buf_impl_t *db = dr->dr_dbuf; 2130 dnode_t *dn = db->db_dnode; 2131 objset_t *os = dn->dn_objset; 2132 uint64_t txg = tx->tx_txg; 2133 2134 ASSERT(dmu_tx_is_syncing(tx)); 2135 2136 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); 2137 2138 mutex_enter(&db->db_mtx); 2139 /* 2140 * To be synced, we must be dirtied. But we 2141 * might have been freed after the dirty. 2142 */ 2143 if (db->db_state == DB_UNCACHED) { 2144 /* This buffer has been freed since it was dirtied */ 2145 ASSERT(db->db.db_data == NULL); 2146 } else if (db->db_state == DB_FILL) { 2147 /* This buffer was freed and is now being re-filled */ 2148 ASSERT(db->db.db_data != dr->dt.dl.dr_data); 2149 } else { 2150 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); 2151 } 2152 DBUF_VERIFY(db); 2153 2154 if (db->db_blkid == DMU_SPILL_BLKID) { 2155 mutex_enter(&dn->dn_mtx); 2156 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR; 2157 mutex_exit(&dn->dn_mtx); 2158 } 2159 2160 /* 2161 * If this is a bonus buffer, simply copy the bonus data into the 2162 * dnode. It will be written out when the dnode is synced (and it 2163 * will be synced, since it must have been dirty for dbuf_sync to 2164 * be called). 2165 */ 2166 if (db->db_blkid == DMU_BONUS_BLKID) { 2167 dbuf_dirty_record_t **drp; 2168 2169 ASSERT(*datap != NULL); 2170 ASSERT3U(db->db_level, ==, 0); 2171 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN); 2172 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen); 2173 if (*datap != db->db.db_data) { 2174 zio_buf_free(*datap, DN_MAX_BONUSLEN); 2175 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER); 2176 } 2177 db->db_data_pending = NULL; 2178 drp = &db->db_last_dirty; 2179 while (*drp != dr) 2180 drp = &(*drp)->dr_next; 2181 ASSERT(dr->dr_next == NULL); 2182 ASSERT(dr->dr_dbuf == db); 2183 *drp = dr->dr_next; 2184 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2185 ASSERT(db->db_dirtycnt > 0); 2186 db->db_dirtycnt -= 1; 2187 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2188 return; 2189 } 2190 2191 /* 2192 * This function may have dropped the db_mtx lock allowing a dmu_sync 2193 * operation to sneak in. As a result, we need to ensure that we 2194 * don't check the dr_override_state until we have returned from 2195 * dbuf_check_blkptr. 2196 */ 2197 dbuf_check_blkptr(dn, db); 2198 2199 /* 2200 * If this buffer is in the middle of an immdiate write, 2201 * wait for the synchronous IO to complete. 2202 */ 2203 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) { 2204 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); 2205 cv_wait(&db->db_changed, &db->db_mtx); 2206 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN); 2207 } 2208 2209 if (db->db_state != DB_NOFILL && 2210 dn->dn_object != DMU_META_DNODE_OBJECT && 2211 refcount_count(&db->db_holds) > 1 && 2212 dr->dt.dl.dr_override_state != DR_OVERRIDDEN && 2213 *datap == db->db_buf) { 2214 /* 2215 * If this buffer is currently "in use" (i.e., there 2216 * are active holds and db_data still references it), 2217 * then make a copy before we start the write so that 2218 * any modifications from the open txg will not leak 2219 * into this write. 2220 * 2221 * NOTE: this copy does not need to be made for 2222 * objects only modified in the syncing context (e.g. 2223 * DNONE_DNODE blocks). 2224 */ 2225 int blksz = arc_buf_size(*datap); 2226 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); 2227 *datap = arc_buf_alloc(os->os_spa, blksz, db, type); 2228 bcopy(db->db.db_data, (*datap)->b_data, blksz); 2229 } 2230 db->db_data_pending = dr; 2231 2232 mutex_exit(&db->db_mtx); 2233 2234 dbuf_write(dr, *datap, tx); 2235 2236 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2237 if (dn->dn_object == DMU_META_DNODE_OBJECT) 2238 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr); 2239 else 2240 zio_nowait(dr->dr_zio); 2241 } 2242 2243 void 2244 dbuf_sync_list(list_t *list, dmu_tx_t *tx) 2245 { 2246 dbuf_dirty_record_t *dr; 2247 2248 while (dr = list_head(list)) { 2249 if (dr->dr_zio != NULL) { 2250 /* 2251 * If we find an already initialized zio then we 2252 * are processing the meta-dnode, and we have finished. 2253 * The dbufs for all dnodes are put back on the list 2254 * during processing, so that we can zio_wait() 2255 * these IOs after initiating all child IOs. 2256 */ 2257 ASSERT3U(dr->dr_dbuf->db.db_object, ==, 2258 DMU_META_DNODE_OBJECT); 2259 break; 2260 } 2261 list_remove(list, dr); 2262 if (dr->dr_dbuf->db_level > 0) 2263 dbuf_sync_indirect(dr, tx); 2264 else 2265 dbuf_sync_leaf(dr, tx); 2266 } 2267 } 2268 2269 /* ARGSUSED */ 2270 static void 2271 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb) 2272 { 2273 dmu_buf_impl_t *db = vdb; 2274 blkptr_t *bp = zio->io_bp; 2275 blkptr_t *bp_orig = &zio->io_bp_orig; 2276 dnode_t *dn = db->db_dnode; 2277 spa_t *spa = zio->io_spa; 2278 int64_t delta; 2279 uint64_t fill = 0; 2280 int i; 2281 2282 ASSERT(db->db_blkptr == bp); 2283 2284 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig); 2285 dnode_diduse_space(dn, delta - zio->io_prev_space_delta); 2286 zio->io_prev_space_delta = delta; 2287 2288 if (BP_IS_HOLE(bp)) { 2289 ASSERT(bp->blk_fill == 0); 2290 return; 2291 } 2292 2293 ASSERT((db->db_blkid != DMU_SPILL_BLKID && 2294 BP_GET_TYPE(bp) == dn->dn_type) || 2295 (db->db_blkid == DMU_SPILL_BLKID && 2296 BP_GET_TYPE(bp) == dn->dn_bonustype)); 2297 ASSERT(BP_GET_LEVEL(bp) == db->db_level); 2298 2299 mutex_enter(&db->db_mtx); 2300 2301 #ifdef ZFS_DEBUG 2302 if (db->db_blkid == DMU_SPILL_BLKID) { 2303 dnode_t *dn = db->db_dnode; 2304 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2305 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2306 db->db_blkptr == &dn->dn_phys->dn_spill); 2307 } 2308 #endif 2309 2310 if (db->db_level == 0) { 2311 mutex_enter(&dn->dn_mtx); 2312 if (db->db_blkid > dn->dn_phys->dn_maxblkid && 2313 db->db_blkid != DMU_SPILL_BLKID) 2314 dn->dn_phys->dn_maxblkid = db->db_blkid; 2315 mutex_exit(&dn->dn_mtx); 2316 2317 if (dn->dn_type == DMU_OT_DNODE) { 2318 dnode_phys_t *dnp = db->db.db_data; 2319 for (i = db->db.db_size >> DNODE_SHIFT; i > 0; 2320 i--, dnp++) { 2321 if (dnp->dn_type != DMU_OT_NONE) 2322 fill++; 2323 } 2324 } else { 2325 fill = 1; 2326 } 2327 } else { 2328 blkptr_t *ibp = db->db.db_data; 2329 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2330 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) { 2331 if (BP_IS_HOLE(ibp)) 2332 continue; 2333 fill += ibp->blk_fill; 2334 } 2335 } 2336 2337 bp->blk_fill = fill; 2338 2339 mutex_exit(&db->db_mtx); 2340 } 2341 2342 /* ARGSUSED */ 2343 static void 2344 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb) 2345 { 2346 dmu_buf_impl_t *db = vdb; 2347 blkptr_t *bp = zio->io_bp; 2348 blkptr_t *bp_orig = &zio->io_bp_orig; 2349 dnode_t *dn = db->db_dnode; 2350 objset_t *os = dn->dn_objset; 2351 uint64_t txg = zio->io_txg; 2352 dbuf_dirty_record_t **drp, *dr; 2353 2354 ASSERT3U(zio->io_error, ==, 0); 2355 ASSERT(db->db_blkptr == bp); 2356 2357 if (zio->io_flags & ZIO_FLAG_IO_REWRITE) { 2358 ASSERT(BP_EQUAL(bp, bp_orig)); 2359 } else { 2360 dsl_dataset_t *ds = os->os_dsl_dataset; 2361 dmu_tx_t *tx = os->os_synctx; 2362 2363 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE); 2364 dsl_dataset_block_born(ds, bp, tx); 2365 } 2366 2367 mutex_enter(&db->db_mtx); 2368 2369 DBUF_VERIFY(db); 2370 2371 drp = &db->db_last_dirty; 2372 while ((dr = *drp) != db->db_data_pending) 2373 drp = &dr->dr_next; 2374 ASSERT(!list_link_active(&dr->dr_dirty_node)); 2375 ASSERT(dr->dr_txg == txg); 2376 ASSERT(dr->dr_dbuf == db); 2377 ASSERT(dr->dr_next == NULL); 2378 *drp = dr->dr_next; 2379 2380 #ifdef ZFS_DEBUG 2381 if (db->db_blkid == DMU_SPILL_BLKID) { 2382 dnode_t *dn = db->db_dnode; 2383 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); 2384 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && 2385 db->db_blkptr == &dn->dn_phys->dn_spill); 2386 } 2387 #endif 2388 2389 if (db->db_level == 0) { 2390 ASSERT(db->db_blkid != DMU_BONUS_BLKID); 2391 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN); 2392 if (db->db_state != DB_NOFILL) { 2393 if (dr->dt.dl.dr_data != db->db_buf) 2394 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, 2395 db) == 1); 2396 else if (!arc_released(db->db_buf)) 2397 arc_set_callback(db->db_buf, dbuf_do_evict, db); 2398 } 2399 } else { 2400 ASSERT(list_head(&dr->dt.di.dr_children) == NULL); 2401 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); 2402 if (!BP_IS_HOLE(db->db_blkptr)) { 2403 int epbs = 2404 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2405 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, 2406 db->db.db_size); 2407 ASSERT3U(dn->dn_phys->dn_maxblkid 2408 >> (db->db_level * epbs), >=, db->db_blkid); 2409 arc_set_callback(db->db_buf, dbuf_do_evict, db); 2410 } 2411 mutex_destroy(&dr->dt.di.dr_mtx); 2412 list_destroy(&dr->dt.di.dr_children); 2413 } 2414 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 2415 2416 cv_broadcast(&db->db_changed); 2417 ASSERT(db->db_dirtycnt > 0); 2418 db->db_dirtycnt -= 1; 2419 db->db_data_pending = NULL; 2420 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg); 2421 } 2422 2423 static void 2424 dbuf_write_nofill_ready(zio_t *zio) 2425 { 2426 dbuf_write_ready(zio, NULL, zio->io_private); 2427 } 2428 2429 static void 2430 dbuf_write_nofill_done(zio_t *zio) 2431 { 2432 dbuf_write_done(zio, NULL, zio->io_private); 2433 } 2434 2435 static void 2436 dbuf_write_override_ready(zio_t *zio) 2437 { 2438 dbuf_dirty_record_t *dr = zio->io_private; 2439 dmu_buf_impl_t *db = dr->dr_dbuf; 2440 2441 dbuf_write_ready(zio, NULL, db); 2442 } 2443 2444 static void 2445 dbuf_write_override_done(zio_t *zio) 2446 { 2447 dbuf_dirty_record_t *dr = zio->io_private; 2448 dmu_buf_impl_t *db = dr->dr_dbuf; 2449 blkptr_t *obp = &dr->dt.dl.dr_overridden_by; 2450 2451 mutex_enter(&db->db_mtx); 2452 if (!BP_EQUAL(zio->io_bp, obp)) { 2453 if (!BP_IS_HOLE(obp)) 2454 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp); 2455 arc_release(dr->dt.dl.dr_data, db); 2456 } 2457 mutex_exit(&db->db_mtx); 2458 2459 dbuf_write_done(zio, NULL, db); 2460 } 2461 2462 static void 2463 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) 2464 { 2465 dmu_buf_impl_t *db = dr->dr_dbuf; 2466 dnode_t *dn = db->db_dnode; 2467 objset_t *os = dn->dn_objset; 2468 dmu_buf_impl_t *parent = db->db_parent; 2469 uint64_t txg = tx->tx_txg; 2470 zbookmark_t zb; 2471 zio_prop_t zp; 2472 zio_t *zio; 2473 int wp_flag = 0; 2474 2475 if (db->db_state != DB_NOFILL) { 2476 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) { 2477 /* 2478 * Private object buffers are released here rather 2479 * than in dbuf_dirty() since they are only modified 2480 * in the syncing context and we don't want the 2481 * overhead of making multiple copies of the data. 2482 */ 2483 if (BP_IS_HOLE(db->db_blkptr)) { 2484 arc_buf_thaw(data); 2485 } else { 2486 dbuf_release_bp(db); 2487 } 2488 } 2489 } 2490 2491 if (parent != dn->dn_dbuf) { 2492 ASSERT(parent && parent->db_data_pending); 2493 ASSERT(db->db_level == parent->db_level-1); 2494 ASSERT(arc_released(parent->db_buf)); 2495 zio = parent->db_data_pending->dr_zio; 2496 } else { 2497 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && 2498 db->db_blkid != DMU_SPILL_BLKID) || 2499 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); 2500 if (db->db_blkid != DMU_SPILL_BLKID) 2501 ASSERT3P(db->db_blkptr, ==, 2502 &dn->dn_phys->dn_blkptr[db->db_blkid]); 2503 zio = dn->dn_zio; 2504 } 2505 2506 ASSERT(db->db_level == 0 || data == db->db_buf); 2507 ASSERT3U(db->db_blkptr->blk_birth, <=, txg); 2508 ASSERT(zio); 2509 2510 SET_BOOKMARK(&zb, os->os_dsl_dataset ? 2511 os->os_dsl_dataset->ds_object : DMU_META_OBJSET, 2512 db->db.db_object, db->db_level, db->db_blkid); 2513 2514 if (db->db_blkid == DMU_SPILL_BLKID) 2515 wp_flag = WP_SPILL; 2516 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0; 2517 2518 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp); 2519 2520 if (db->db_level == 0 && dr->dt.dl.dr_override_state == DR_OVERRIDDEN) { 2521 ASSERT(db->db_state != DB_NOFILL); 2522 dr->dr_zio = zio_write(zio, os->os_spa, txg, 2523 db->db_blkptr, data->b_data, arc_buf_size(data), &zp, 2524 dbuf_write_override_ready, dbuf_write_override_done, dr, 2525 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 2526 mutex_enter(&db->db_mtx); 2527 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; 2528 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by, 2529 dr->dt.dl.dr_copies); 2530 mutex_exit(&db->db_mtx); 2531 } else if (db->db_state == DB_NOFILL) { 2532 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF); 2533 dr->dr_zio = zio_write(zio, os->os_spa, txg, 2534 db->db_blkptr, NULL, db->db.db_size, &zp, 2535 dbuf_write_nofill_ready, dbuf_write_nofill_done, db, 2536 ZIO_PRIORITY_ASYNC_WRITE, 2537 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb); 2538 } else { 2539 ASSERT(arc_released(data)); 2540 dr->dr_zio = arc_write(zio, os->os_spa, txg, 2541 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), &zp, 2542 dbuf_write_ready, dbuf_write_done, db, 2543 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); 2544 } 2545 } 2546