1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2012, 2017 by Delphix. All rights reserved. 24 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. 25 * Copyright (c) 2014 Integros [integros.com] 26 * Copyright 2017 RackTop Systems. 27 */ 28 29 #include <sys/zfs_context.h> 30 #include <sys/dbuf.h> 31 #include <sys/dnode.h> 32 #include <sys/dmu.h> 33 #include <sys/dmu_impl.h> 34 #include <sys/dmu_tx.h> 35 #include <sys/dmu_objset.h> 36 #include <sys/dsl_dir.h> 37 #include <sys/dsl_dataset.h> 38 #include <sys/spa.h> 39 #include <sys/zio.h> 40 #include <sys/dmu_zfetch.h> 41 #include <sys/range_tree.h> 42 43 dnode_stats_t dnode_stats = { 44 { "dnode_hold_dbuf_hold", KSTAT_DATA_UINT64 }, 45 { "dnode_hold_dbuf_read", KSTAT_DATA_UINT64 }, 46 { "dnode_hold_alloc_hits", KSTAT_DATA_UINT64 }, 47 { "dnode_hold_alloc_misses", KSTAT_DATA_UINT64 }, 48 { "dnode_hold_alloc_interior", KSTAT_DATA_UINT64 }, 49 { "dnode_hold_alloc_lock_retry", KSTAT_DATA_UINT64 }, 50 { "dnode_hold_alloc_lock_misses", KSTAT_DATA_UINT64 }, 51 { "dnode_hold_alloc_type_none", KSTAT_DATA_UINT64 }, 52 { "dnode_hold_free_hits", KSTAT_DATA_UINT64 }, 53 { "dnode_hold_free_misses", KSTAT_DATA_UINT64 }, 54 { "dnode_hold_free_lock_misses", KSTAT_DATA_UINT64 }, 55 { "dnode_hold_free_lock_retry", KSTAT_DATA_UINT64 }, 56 { "dnode_hold_free_overflow", KSTAT_DATA_UINT64 }, 57 { "dnode_hold_free_refcount", KSTAT_DATA_UINT64 }, 58 { "dnode_hold_free_txg", KSTAT_DATA_UINT64 }, 59 { "dnode_free_interior_lock_retry", KSTAT_DATA_UINT64 }, 60 { "dnode_allocate", KSTAT_DATA_UINT64 }, 61 { "dnode_reallocate", KSTAT_DATA_UINT64 }, 62 { "dnode_buf_evict", KSTAT_DATA_UINT64 }, 63 { "dnode_alloc_next_chunk", KSTAT_DATA_UINT64 }, 64 { "dnode_alloc_race", KSTAT_DATA_UINT64 }, 65 { "dnode_alloc_next_block", KSTAT_DATA_UINT64 }, 66 { "dnode_move_invalid", KSTAT_DATA_UINT64 }, 67 { "dnode_move_recheck1", KSTAT_DATA_UINT64 }, 68 { "dnode_move_recheck2", KSTAT_DATA_UINT64 }, 69 { "dnode_move_special", KSTAT_DATA_UINT64 }, 70 { "dnode_move_handle", KSTAT_DATA_UINT64 }, 71 { "dnode_move_rwlock", KSTAT_DATA_UINT64 }, 72 { "dnode_move_active", KSTAT_DATA_UINT64 }, 73 }; 74 75 static kstat_t *dnode_ksp; 76 static kmem_cache_t *dnode_cache; 77 78 static dnode_phys_t dnode_phys_zero; 79 80 int zfs_default_bs = SPA_MINBLOCKSHIFT; 81 int zfs_default_ibs = DN_MAX_INDBLKSHIFT; 82 83 #ifdef _KERNEL 84 static kmem_cbrc_t dnode_move(void *, void *, size_t, void *); 85 #endif /* _KERNEL */ 86 87 static int 88 dbuf_compare(const void *x1, const void *x2) 89 { 90 const dmu_buf_impl_t *d1 = x1; 91 const dmu_buf_impl_t *d2 = x2; 92 93 if (d1->db_level < d2->db_level) { 94 return (-1); 95 } 96 if (d1->db_level > d2->db_level) { 97 return (1); 98 } 99 100 if (d1->db_blkid < d2->db_blkid) { 101 return (-1); 102 } 103 if (d1->db_blkid > d2->db_blkid) { 104 return (1); 105 } 106 107 if (d1->db_state == DB_SEARCH) { 108 ASSERT3S(d2->db_state, !=, DB_SEARCH); 109 return (-1); 110 } else if (d2->db_state == DB_SEARCH) { 111 ASSERT3S(d1->db_state, !=, DB_SEARCH); 112 return (1); 113 } 114 115 if ((uintptr_t)d1 < (uintptr_t)d2) { 116 return (-1); 117 } 118 if ((uintptr_t)d1 > (uintptr_t)d2) { 119 return (1); 120 } 121 return (0); 122 } 123 124 /* ARGSUSED */ 125 static int 126 dnode_cons(void *arg, void *unused, int kmflag) 127 { 128 dnode_t *dn = arg; 129 int i; 130 131 rw_init(&dn->dn_struct_rwlock, NULL, RW_DEFAULT, NULL); 132 mutex_init(&dn->dn_mtx, NULL, MUTEX_DEFAULT, NULL); 133 mutex_init(&dn->dn_dbufs_mtx, NULL, MUTEX_DEFAULT, NULL); 134 cv_init(&dn->dn_notxholds, NULL, CV_DEFAULT, NULL); 135 136 /* 137 * Every dbuf has a reference, and dropping a tracked reference is 138 * O(number of references), so don't track dn_holds. 139 */ 140 refcount_create_untracked(&dn->dn_holds); 141 refcount_create(&dn->dn_tx_holds); 142 list_link_init(&dn->dn_link); 143 144 bzero(&dn->dn_next_nblkptr[0], sizeof (dn->dn_next_nblkptr)); 145 bzero(&dn->dn_next_nlevels[0], sizeof (dn->dn_next_nlevels)); 146 bzero(&dn->dn_next_indblkshift[0], sizeof (dn->dn_next_indblkshift)); 147 bzero(&dn->dn_next_bonustype[0], sizeof (dn->dn_next_bonustype)); 148 bzero(&dn->dn_rm_spillblk[0], sizeof (dn->dn_rm_spillblk)); 149 bzero(&dn->dn_next_bonuslen[0], sizeof (dn->dn_next_bonuslen)); 150 bzero(&dn->dn_next_blksz[0], sizeof (dn->dn_next_blksz)); 151 152 for (i = 0; i < TXG_SIZE; i++) { 153 list_link_init(&dn->dn_dirty_link[i]); 154 dn->dn_free_ranges[i] = NULL; 155 list_create(&dn->dn_dirty_records[i], 156 sizeof (dbuf_dirty_record_t), 157 offsetof(dbuf_dirty_record_t, dr_dirty_node)); 158 } 159 160 dn->dn_allocated_txg = 0; 161 dn->dn_free_txg = 0; 162 dn->dn_assigned_txg = 0; 163 dn->dn_dirtyctx = 0; 164 dn->dn_dirtyctx_firstset = NULL; 165 dn->dn_bonus = NULL; 166 dn->dn_have_spill = B_FALSE; 167 dn->dn_zio = NULL; 168 dn->dn_oldused = 0; 169 dn->dn_oldflags = 0; 170 dn->dn_olduid = 0; 171 dn->dn_oldgid = 0; 172 dn->dn_newuid = 0; 173 dn->dn_newgid = 0; 174 dn->dn_id_flags = 0; 175 176 dn->dn_dbufs_count = 0; 177 avl_create(&dn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t), 178 offsetof(dmu_buf_impl_t, db_link)); 179 180 dn->dn_moved = 0; 181 return (0); 182 } 183 184 /* ARGSUSED */ 185 static void 186 dnode_dest(void *arg, void *unused) 187 { 188 int i; 189 dnode_t *dn = arg; 190 191 rw_destroy(&dn->dn_struct_rwlock); 192 mutex_destroy(&dn->dn_mtx); 193 mutex_destroy(&dn->dn_dbufs_mtx); 194 cv_destroy(&dn->dn_notxholds); 195 refcount_destroy(&dn->dn_holds); 196 refcount_destroy(&dn->dn_tx_holds); 197 ASSERT(!list_link_active(&dn->dn_link)); 198 199 for (i = 0; i < TXG_SIZE; i++) { 200 ASSERT(!list_link_active(&dn->dn_dirty_link[i])); 201 ASSERT3P(dn->dn_free_ranges[i], ==, NULL); 202 list_destroy(&dn->dn_dirty_records[i]); 203 ASSERT0(dn->dn_next_nblkptr[i]); 204 ASSERT0(dn->dn_next_nlevels[i]); 205 ASSERT0(dn->dn_next_indblkshift[i]); 206 ASSERT0(dn->dn_next_bonustype[i]); 207 ASSERT0(dn->dn_rm_spillblk[i]); 208 ASSERT0(dn->dn_next_bonuslen[i]); 209 ASSERT0(dn->dn_next_blksz[i]); 210 } 211 212 ASSERT0(dn->dn_allocated_txg); 213 ASSERT0(dn->dn_free_txg); 214 ASSERT0(dn->dn_assigned_txg); 215 ASSERT0(dn->dn_dirtyctx); 216 ASSERT3P(dn->dn_dirtyctx_firstset, ==, NULL); 217 ASSERT3P(dn->dn_bonus, ==, NULL); 218 ASSERT(!dn->dn_have_spill); 219 ASSERT3P(dn->dn_zio, ==, NULL); 220 ASSERT0(dn->dn_oldused); 221 ASSERT0(dn->dn_oldflags); 222 ASSERT0(dn->dn_olduid); 223 ASSERT0(dn->dn_oldgid); 224 ASSERT0(dn->dn_newuid); 225 ASSERT0(dn->dn_newgid); 226 ASSERT0(dn->dn_id_flags); 227 228 ASSERT0(dn->dn_dbufs_count); 229 avl_destroy(&dn->dn_dbufs); 230 } 231 232 void 233 dnode_init(void) 234 { 235 ASSERT(dnode_cache == NULL); 236 dnode_cache = kmem_cache_create("dnode_t", 237 sizeof (dnode_t), 238 0, dnode_cons, dnode_dest, NULL, NULL, NULL, 0); 239 #ifdef _KERNEL 240 kmem_cache_set_move(dnode_cache, dnode_move); 241 242 dnode_ksp = kstat_create("zfs", 0, "dnodestats", "misc", 243 KSTAT_TYPE_NAMED, sizeof (dnode_stats) / sizeof (kstat_named_t), 244 KSTAT_FLAG_VIRTUAL); 245 if (dnode_ksp != NULL) { 246 dnode_ksp->ks_data = &dnode_stats; 247 kstat_install(dnode_ksp); 248 } 249 #endif /* _KERNEL */ 250 } 251 252 void 253 dnode_fini(void) 254 { 255 if (dnode_ksp != NULL) { 256 kstat_delete(dnode_ksp); 257 dnode_ksp = NULL; 258 } 259 260 kmem_cache_destroy(dnode_cache); 261 dnode_cache = NULL; 262 } 263 264 265 #ifdef ZFS_DEBUG 266 void 267 dnode_verify(dnode_t *dn) 268 { 269 int drop_struct_lock = FALSE; 270 271 ASSERT(dn->dn_phys); 272 ASSERT(dn->dn_objset); 273 ASSERT(dn->dn_handle->dnh_dnode == dn); 274 275 ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type)); 276 277 if (!(zfs_flags & ZFS_DEBUG_DNODE_VERIFY)) 278 return; 279 280 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 281 rw_enter(&dn->dn_struct_rwlock, RW_READER); 282 drop_struct_lock = TRUE; 283 } 284 if (dn->dn_phys->dn_type != DMU_OT_NONE || dn->dn_allocated_txg != 0) { 285 int i; 286 int max_bonuslen = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots); 287 ASSERT3U(dn->dn_indblkshift, >=, 0); 288 ASSERT3U(dn->dn_indblkshift, <=, SPA_MAXBLOCKSHIFT); 289 if (dn->dn_datablkshift) { 290 ASSERT3U(dn->dn_datablkshift, >=, SPA_MINBLOCKSHIFT); 291 ASSERT3U(dn->dn_datablkshift, <=, SPA_MAXBLOCKSHIFT); 292 ASSERT3U(1<<dn->dn_datablkshift, ==, dn->dn_datablksz); 293 } 294 ASSERT3U(dn->dn_nlevels, <=, 30); 295 ASSERT(DMU_OT_IS_VALID(dn->dn_type)); 296 ASSERT3U(dn->dn_nblkptr, >=, 1); 297 ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR); 298 ASSERT3U(dn->dn_bonuslen, <=, max_bonuslen); 299 ASSERT3U(dn->dn_datablksz, ==, 300 dn->dn_datablkszsec << SPA_MINBLOCKSHIFT); 301 ASSERT3U(ISP2(dn->dn_datablksz), ==, dn->dn_datablkshift != 0); 302 ASSERT3U((dn->dn_nblkptr - 1) * sizeof (blkptr_t) + 303 dn->dn_bonuslen, <=, max_bonuslen); 304 for (i = 0; i < TXG_SIZE; i++) { 305 ASSERT3U(dn->dn_next_nlevels[i], <=, dn->dn_nlevels); 306 } 307 } 308 if (dn->dn_phys->dn_type != DMU_OT_NONE) 309 ASSERT3U(dn->dn_phys->dn_nlevels, <=, dn->dn_nlevels); 310 ASSERT(DMU_OBJECT_IS_SPECIAL(dn->dn_object) || dn->dn_dbuf != NULL); 311 if (dn->dn_dbuf != NULL) { 312 ASSERT3P(dn->dn_phys, ==, 313 (dnode_phys_t *)dn->dn_dbuf->db.db_data + 314 (dn->dn_object % (dn->dn_dbuf->db.db_size >> DNODE_SHIFT))); 315 } 316 if (drop_struct_lock) 317 rw_exit(&dn->dn_struct_rwlock); 318 } 319 #endif 320 321 void 322 dnode_byteswap(dnode_phys_t *dnp) 323 { 324 uint64_t *buf64 = (void*)&dnp->dn_blkptr; 325 int i; 326 327 if (dnp->dn_type == DMU_OT_NONE) { 328 bzero(dnp, sizeof (dnode_phys_t)); 329 return; 330 } 331 332 dnp->dn_datablkszsec = BSWAP_16(dnp->dn_datablkszsec); 333 dnp->dn_bonuslen = BSWAP_16(dnp->dn_bonuslen); 334 dnp->dn_extra_slots = BSWAP_8(dnp->dn_extra_slots); 335 dnp->dn_maxblkid = BSWAP_64(dnp->dn_maxblkid); 336 dnp->dn_used = BSWAP_64(dnp->dn_used); 337 338 /* 339 * dn_nblkptr is only one byte, so it's OK to read it in either 340 * byte order. We can't read dn_bouslen. 341 */ 342 ASSERT(dnp->dn_indblkshift <= SPA_MAXBLOCKSHIFT); 343 ASSERT(dnp->dn_nblkptr <= DN_MAX_NBLKPTR); 344 for (i = 0; i < dnp->dn_nblkptr * sizeof (blkptr_t)/8; i++) 345 buf64[i] = BSWAP_64(buf64[i]); 346 347 /* 348 * OK to check dn_bonuslen for zero, because it won't matter if 349 * we have the wrong byte order. This is necessary because the 350 * dnode dnode is smaller than a regular dnode. 351 */ 352 if (dnp->dn_bonuslen != 0) { 353 /* 354 * Note that the bonus length calculated here may be 355 * longer than the actual bonus buffer. This is because 356 * we always put the bonus buffer after the last block 357 * pointer (instead of packing it against the end of the 358 * dnode buffer). 359 */ 360 int off = (dnp->dn_nblkptr-1) * sizeof (blkptr_t); 361 int slots = dnp->dn_extra_slots + 1; 362 size_t len = DN_SLOTS_TO_BONUSLEN(slots) - off; 363 ASSERT(DMU_OT_IS_VALID(dnp->dn_bonustype)); 364 dmu_object_byteswap_t byteswap = 365 DMU_OT_BYTESWAP(dnp->dn_bonustype); 366 dmu_ot_byteswap[byteswap].ob_func(dnp->dn_bonus + off, len); 367 } 368 369 /* Swap SPILL block if we have one */ 370 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) 371 byteswap_uint64_array(DN_SPILL_BLKPTR(dnp), sizeof (blkptr_t)); 372 373 } 374 375 void 376 dnode_buf_byteswap(void *vbuf, size_t size) 377 { 378 int i = 0; 379 380 ASSERT3U(sizeof (dnode_phys_t), ==, (1<<DNODE_SHIFT)); 381 ASSERT((size & (sizeof (dnode_phys_t)-1)) == 0); 382 383 while (i < size) { 384 dnode_phys_t *dnp = (void *)(((char *)vbuf) + i); 385 dnode_byteswap(dnp); 386 387 i += DNODE_MIN_SIZE; 388 if (dnp->dn_type != DMU_OT_NONE) 389 i += dnp->dn_extra_slots * DNODE_MIN_SIZE; 390 } 391 } 392 393 void 394 dnode_setbonuslen(dnode_t *dn, int newsize, dmu_tx_t *tx) 395 { 396 ASSERT3U(refcount_count(&dn->dn_holds), >=, 1); 397 398 dnode_setdirty(dn, tx); 399 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 400 ASSERT3U(newsize, <=, DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) - 401 (dn->dn_nblkptr-1) * sizeof (blkptr_t)); 402 dn->dn_bonuslen = newsize; 403 if (newsize == 0) 404 dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = DN_ZERO_BONUSLEN; 405 else 406 dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen; 407 rw_exit(&dn->dn_struct_rwlock); 408 } 409 410 void 411 dnode_setbonus_type(dnode_t *dn, dmu_object_type_t newtype, dmu_tx_t *tx) 412 { 413 ASSERT3U(refcount_count(&dn->dn_holds), >=, 1); 414 dnode_setdirty(dn, tx); 415 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 416 dn->dn_bonustype = newtype; 417 dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype; 418 rw_exit(&dn->dn_struct_rwlock); 419 } 420 421 void 422 dnode_rm_spill(dnode_t *dn, dmu_tx_t *tx) 423 { 424 ASSERT3U(refcount_count(&dn->dn_holds), >=, 1); 425 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 426 dnode_setdirty(dn, tx); 427 dn->dn_rm_spillblk[tx->tx_txg&TXG_MASK] = DN_KILL_SPILLBLK; 428 dn->dn_have_spill = B_FALSE; 429 } 430 431 static void 432 dnode_setdblksz(dnode_t *dn, int size) 433 { 434 ASSERT0(P2PHASE(size, SPA_MINBLOCKSIZE)); 435 ASSERT3U(size, <=, SPA_MAXBLOCKSIZE); 436 ASSERT3U(size, >=, SPA_MINBLOCKSIZE); 437 ASSERT3U(size >> SPA_MINBLOCKSHIFT, <, 438 1<<(sizeof (dn->dn_phys->dn_datablkszsec) * 8)); 439 dn->dn_datablksz = size; 440 dn->dn_datablkszsec = size >> SPA_MINBLOCKSHIFT; 441 dn->dn_datablkshift = ISP2(size) ? highbit64(size - 1) : 0; 442 } 443 444 static dnode_t * 445 dnode_create(objset_t *os, dnode_phys_t *dnp, dmu_buf_impl_t *db, 446 uint64_t object, dnode_handle_t *dnh) 447 { 448 dnode_t *dn; 449 450 dn = kmem_cache_alloc(dnode_cache, KM_SLEEP); 451 #ifdef _KERNEL 452 ASSERT(!POINTER_IS_VALID(dn->dn_objset)); 453 #endif /* _KERNEL */ 454 dn->dn_moved = 0; 455 456 /* 457 * Defer setting dn_objset until the dnode is ready to be a candidate 458 * for the dnode_move() callback. 459 */ 460 dn->dn_object = object; 461 dn->dn_dbuf = db; 462 dn->dn_handle = dnh; 463 dn->dn_phys = dnp; 464 465 if (dnp->dn_datablkszsec) { 466 dnode_setdblksz(dn, dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT); 467 } else { 468 dn->dn_datablksz = 0; 469 dn->dn_datablkszsec = 0; 470 dn->dn_datablkshift = 0; 471 } 472 dn->dn_indblkshift = dnp->dn_indblkshift; 473 dn->dn_nlevels = dnp->dn_nlevels; 474 dn->dn_type = dnp->dn_type; 475 dn->dn_nblkptr = dnp->dn_nblkptr; 476 dn->dn_checksum = dnp->dn_checksum; 477 dn->dn_compress = dnp->dn_compress; 478 dn->dn_bonustype = dnp->dn_bonustype; 479 dn->dn_bonuslen = dnp->dn_bonuslen; 480 dn->dn_num_slots = dnp->dn_extra_slots + 1; 481 dn->dn_maxblkid = dnp->dn_maxblkid; 482 dn->dn_have_spill = ((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0); 483 dn->dn_id_flags = 0; 484 485 dmu_zfetch_init(&dn->dn_zfetch, dn); 486 487 ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type)); 488 ASSERT(zrl_is_locked(&dnh->dnh_zrlock)); 489 ASSERT(!DN_SLOT_IS_PTR(dnh->dnh_dnode)); 490 491 mutex_enter(&os->os_lock); 492 493 /* 494 * Exclude special dnodes from os_dnodes so an empty os_dnodes 495 * signifies that the special dnodes have no references from 496 * their children (the entries in os_dnodes). This allows 497 * dnode_destroy() to easily determine if the last child has 498 * been removed and then complete eviction of the objset. 499 */ 500 if (!DMU_OBJECT_IS_SPECIAL(object)) 501 list_insert_head(&os->os_dnodes, dn); 502 membar_producer(); 503 504 /* 505 * Everything else must be valid before assigning dn_objset 506 * makes the dnode eligible for dnode_move(). 507 */ 508 dn->dn_objset = os; 509 510 dnh->dnh_dnode = dn; 511 mutex_exit(&os->os_lock); 512 513 arc_space_consume(sizeof (dnode_t), ARC_SPACE_OTHER); 514 515 return (dn); 516 } 517 518 /* 519 * Caller must be holding the dnode handle, which is released upon return. 520 */ 521 static void 522 dnode_destroy(dnode_t *dn) 523 { 524 objset_t *os = dn->dn_objset; 525 boolean_t complete_os_eviction = B_FALSE; 526 527 ASSERT((dn->dn_id_flags & DN_ID_NEW_EXIST) == 0); 528 529 mutex_enter(&os->os_lock); 530 POINTER_INVALIDATE(&dn->dn_objset); 531 if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) { 532 list_remove(&os->os_dnodes, dn); 533 complete_os_eviction = 534 list_is_empty(&os->os_dnodes) && 535 list_link_active(&os->os_evicting_node); 536 } 537 mutex_exit(&os->os_lock); 538 539 /* the dnode can no longer move, so we can release the handle */ 540 if (!zrl_is_locked(&dn->dn_handle->dnh_zrlock)) 541 zrl_remove(&dn->dn_handle->dnh_zrlock); 542 543 dn->dn_allocated_txg = 0; 544 dn->dn_free_txg = 0; 545 dn->dn_assigned_txg = 0; 546 547 dn->dn_dirtyctx = 0; 548 if (dn->dn_dirtyctx_firstset != NULL) { 549 kmem_free(dn->dn_dirtyctx_firstset, 1); 550 dn->dn_dirtyctx_firstset = NULL; 551 } 552 if (dn->dn_bonus != NULL) { 553 mutex_enter(&dn->dn_bonus->db_mtx); 554 dbuf_destroy(dn->dn_bonus); 555 dn->dn_bonus = NULL; 556 } 557 dn->dn_zio = NULL; 558 559 dn->dn_have_spill = B_FALSE; 560 dn->dn_oldused = 0; 561 dn->dn_oldflags = 0; 562 dn->dn_olduid = 0; 563 dn->dn_oldgid = 0; 564 dn->dn_newuid = 0; 565 dn->dn_newgid = 0; 566 dn->dn_id_flags = 0; 567 568 dmu_zfetch_fini(&dn->dn_zfetch); 569 kmem_cache_free(dnode_cache, dn); 570 arc_space_return(sizeof (dnode_t), ARC_SPACE_OTHER); 571 572 if (complete_os_eviction) 573 dmu_objset_evict_done(os); 574 } 575 576 void 577 dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs, 578 dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx) 579 { 580 int i; 581 582 ASSERT3U(dn_slots, >, 0); 583 ASSERT3U(dn_slots << DNODE_SHIFT, <=, 584 spa_maxdnodesize(dmu_objset_spa(dn->dn_objset))); 585 ASSERT3U(blocksize, <=, 586 spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); 587 if (blocksize == 0) 588 blocksize = 1 << zfs_default_bs; 589 else 590 blocksize = P2ROUNDUP(blocksize, SPA_MINBLOCKSIZE); 591 592 if (ibs == 0) 593 ibs = zfs_default_ibs; 594 595 ibs = MIN(MAX(ibs, DN_MIN_INDBLKSHIFT), DN_MAX_INDBLKSHIFT); 596 597 dprintf("os=%p obj=%" PRIu64 " txg=%" PRIu64 598 " blocksize=%d ibs=%d dn_slots=%d\n", 599 dn->dn_objset, dn->dn_object, tx->tx_txg, blocksize, ibs, dn_slots); 600 DNODE_STAT_BUMP(dnode_allocate); 601 602 ASSERT(dn->dn_type == DMU_OT_NONE); 603 ASSERT(bcmp(dn->dn_phys, &dnode_phys_zero, sizeof (dnode_phys_t)) == 0); 604 ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE); 605 ASSERT(ot != DMU_OT_NONE); 606 ASSERT(DMU_OT_IS_VALID(ot)); 607 ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) || 608 (bonustype == DMU_OT_SA && bonuslen == 0) || 609 (bonustype != DMU_OT_NONE && bonuslen != 0)); 610 ASSERT(DMU_OT_IS_VALID(bonustype)); 611 ASSERT3U(bonuslen, <=, DN_SLOTS_TO_BONUSLEN(dn_slots)); 612 ASSERT(dn->dn_type == DMU_OT_NONE); 613 ASSERT0(dn->dn_maxblkid); 614 ASSERT0(dn->dn_allocated_txg); 615 ASSERT0(dn->dn_assigned_txg); 616 ASSERT(refcount_is_zero(&dn->dn_tx_holds)); 617 ASSERT3U(refcount_count(&dn->dn_holds), <=, 1); 618 ASSERT(avl_is_empty(&dn->dn_dbufs)); 619 620 for (i = 0; i < TXG_SIZE; i++) { 621 ASSERT0(dn->dn_next_nblkptr[i]); 622 ASSERT0(dn->dn_next_nlevels[i]); 623 ASSERT0(dn->dn_next_indblkshift[i]); 624 ASSERT0(dn->dn_next_bonuslen[i]); 625 ASSERT0(dn->dn_next_bonustype[i]); 626 ASSERT0(dn->dn_rm_spillblk[i]); 627 ASSERT0(dn->dn_next_blksz[i]); 628 ASSERT(!list_link_active(&dn->dn_dirty_link[i])); 629 ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL); 630 ASSERT3P(dn->dn_free_ranges[i], ==, NULL); 631 } 632 633 dn->dn_type = ot; 634 dnode_setdblksz(dn, blocksize); 635 dn->dn_indblkshift = ibs; 636 dn->dn_nlevels = 1; 637 dn->dn_num_slots = dn_slots; 638 if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */ 639 dn->dn_nblkptr = 1; 640 else { 641 dn->dn_nblkptr = MIN(DN_MAX_NBLKPTR, 642 1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >> 643 SPA_BLKPTRSHIFT)); 644 } 645 646 dn->dn_bonustype = bonustype; 647 dn->dn_bonuslen = bonuslen; 648 dn->dn_checksum = ZIO_CHECKSUM_INHERIT; 649 dn->dn_compress = ZIO_COMPRESS_INHERIT; 650 dn->dn_dirtyctx = 0; 651 652 dn->dn_free_txg = 0; 653 if (dn->dn_dirtyctx_firstset) { 654 kmem_free(dn->dn_dirtyctx_firstset, 1); 655 dn->dn_dirtyctx_firstset = NULL; 656 } 657 658 dn->dn_allocated_txg = tx->tx_txg; 659 dn->dn_id_flags = 0; 660 661 dnode_setdirty(dn, tx); 662 dn->dn_next_indblkshift[tx->tx_txg & TXG_MASK] = ibs; 663 dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen; 664 dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype; 665 dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = dn->dn_datablksz; 666 } 667 668 void 669 dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, 670 dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx) 671 { 672 int nblkptr; 673 674 ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE); 675 ASSERT3U(blocksize, <=, 676 spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); 677 ASSERT0(blocksize % SPA_MINBLOCKSIZE); 678 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT || dmu_tx_private_ok(tx)); 679 ASSERT(tx->tx_txg != 0); 680 ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) || 681 (bonustype != DMU_OT_NONE && bonuslen != 0) || 682 (bonustype == DMU_OT_SA && bonuslen == 0)); 683 ASSERT(DMU_OT_IS_VALID(bonustype)); 684 ASSERT3U(bonuslen, <=, 685 DN_BONUS_SIZE(spa_maxdnodesize(dmu_objset_spa(dn->dn_objset)))); 686 687 dn_slots = dn_slots > 0 ? dn_slots : DNODE_MIN_SLOTS; 688 689 dnode_free_interior_slots(dn); 690 DNODE_STAT_BUMP(dnode_reallocate); 691 692 /* clean up any unreferenced dbufs */ 693 dnode_evict_dbufs(dn); 694 695 dn->dn_id_flags = 0; 696 697 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 698 dnode_setdirty(dn, tx); 699 if (dn->dn_datablksz != blocksize) { 700 /* change blocksize */ 701 ASSERT(dn->dn_maxblkid == 0 && 702 (BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) || 703 dnode_block_freed(dn, 0))); 704 dnode_setdblksz(dn, blocksize); 705 dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize; 706 } 707 if (dn->dn_bonuslen != bonuslen) 708 dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen; 709 710 if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */ 711 nblkptr = 1; 712 else 713 nblkptr = MIN(DN_MAX_NBLKPTR, 714 1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >> 715 SPA_BLKPTRSHIFT)); 716 if (dn->dn_bonustype != bonustype) 717 dn->dn_next_bonustype[tx->tx_txg&TXG_MASK] = bonustype; 718 if (dn->dn_nblkptr != nblkptr) 719 dn->dn_next_nblkptr[tx->tx_txg&TXG_MASK] = nblkptr; 720 if (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR) { 721 dbuf_rm_spill(dn, tx); 722 dnode_rm_spill(dn, tx); 723 } 724 rw_exit(&dn->dn_struct_rwlock); 725 726 /* change type */ 727 dn->dn_type = ot; 728 729 /* change bonus size and type */ 730 mutex_enter(&dn->dn_mtx); 731 dn->dn_bonustype = bonustype; 732 dn->dn_bonuslen = bonuslen; 733 dn->dn_num_slots = dn_slots; 734 dn->dn_nblkptr = nblkptr; 735 dn->dn_checksum = ZIO_CHECKSUM_INHERIT; 736 dn->dn_compress = ZIO_COMPRESS_INHERIT; 737 ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR); 738 739 /* fix up the bonus db_size */ 740 if (dn->dn_bonus) { 741 dn->dn_bonus->db.db_size = 742 DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) - 743 (dn->dn_nblkptr - 1) * sizeof (blkptr_t); 744 ASSERT(dn->dn_bonuslen <= dn->dn_bonus->db.db_size); 745 } 746 747 dn->dn_allocated_txg = tx->tx_txg; 748 mutex_exit(&dn->dn_mtx); 749 } 750 751 #ifdef _KERNEL 752 static void 753 dnode_move_impl(dnode_t *odn, dnode_t *ndn) 754 { 755 int i; 756 757 ASSERT(!RW_LOCK_HELD(&odn->dn_struct_rwlock)); 758 ASSERT(MUTEX_NOT_HELD(&odn->dn_mtx)); 759 ASSERT(MUTEX_NOT_HELD(&odn->dn_dbufs_mtx)); 760 ASSERT(!RW_LOCK_HELD(&odn->dn_zfetch.zf_rwlock)); 761 762 /* Copy fields. */ 763 ndn->dn_objset = odn->dn_objset; 764 ndn->dn_object = odn->dn_object; 765 ndn->dn_dbuf = odn->dn_dbuf; 766 ndn->dn_handle = odn->dn_handle; 767 ndn->dn_phys = odn->dn_phys; 768 ndn->dn_type = odn->dn_type; 769 ndn->dn_bonuslen = odn->dn_bonuslen; 770 ndn->dn_bonustype = odn->dn_bonustype; 771 ndn->dn_nblkptr = odn->dn_nblkptr; 772 ndn->dn_checksum = odn->dn_checksum; 773 ndn->dn_compress = odn->dn_compress; 774 ndn->dn_nlevels = odn->dn_nlevels; 775 ndn->dn_indblkshift = odn->dn_indblkshift; 776 ndn->dn_datablkshift = odn->dn_datablkshift; 777 ndn->dn_datablkszsec = odn->dn_datablkszsec; 778 ndn->dn_datablksz = odn->dn_datablksz; 779 ndn->dn_maxblkid = odn->dn_maxblkid; 780 ndn->dn_num_slots = odn->dn_num_slots; 781 bcopy(&odn->dn_next_type[0], &ndn->dn_next_type[0], 782 sizeof (odn->dn_next_type)); 783 bcopy(&odn->dn_next_nblkptr[0], &ndn->dn_next_nblkptr[0], 784 sizeof (odn->dn_next_nblkptr)); 785 bcopy(&odn->dn_next_nlevels[0], &ndn->dn_next_nlevels[0], 786 sizeof (odn->dn_next_nlevels)); 787 bcopy(&odn->dn_next_indblkshift[0], &ndn->dn_next_indblkshift[0], 788 sizeof (odn->dn_next_indblkshift)); 789 bcopy(&odn->dn_next_bonustype[0], &ndn->dn_next_bonustype[0], 790 sizeof (odn->dn_next_bonustype)); 791 bcopy(&odn->dn_rm_spillblk[0], &ndn->dn_rm_spillblk[0], 792 sizeof (odn->dn_rm_spillblk)); 793 bcopy(&odn->dn_next_bonuslen[0], &ndn->dn_next_bonuslen[0], 794 sizeof (odn->dn_next_bonuslen)); 795 bcopy(&odn->dn_next_blksz[0], &ndn->dn_next_blksz[0], 796 sizeof (odn->dn_next_blksz)); 797 for (i = 0; i < TXG_SIZE; i++) { 798 list_move_tail(&ndn->dn_dirty_records[i], 799 &odn->dn_dirty_records[i]); 800 } 801 bcopy(&odn->dn_free_ranges[0], &ndn->dn_free_ranges[0], 802 sizeof (odn->dn_free_ranges)); 803 ndn->dn_allocated_txg = odn->dn_allocated_txg; 804 ndn->dn_free_txg = odn->dn_free_txg; 805 ndn->dn_assigned_txg = odn->dn_assigned_txg; 806 ndn->dn_dirtyctx = odn->dn_dirtyctx; 807 ndn->dn_dirtyctx_firstset = odn->dn_dirtyctx_firstset; 808 ASSERT(refcount_count(&odn->dn_tx_holds) == 0); 809 refcount_transfer(&ndn->dn_holds, &odn->dn_holds); 810 ASSERT(avl_is_empty(&ndn->dn_dbufs)); 811 avl_swap(&ndn->dn_dbufs, &odn->dn_dbufs); 812 ndn->dn_dbufs_count = odn->dn_dbufs_count; 813 ndn->dn_bonus = odn->dn_bonus; 814 ndn->dn_have_spill = odn->dn_have_spill; 815 ndn->dn_zio = odn->dn_zio; 816 ndn->dn_oldused = odn->dn_oldused; 817 ndn->dn_oldflags = odn->dn_oldflags; 818 ndn->dn_olduid = odn->dn_olduid; 819 ndn->dn_oldgid = odn->dn_oldgid; 820 ndn->dn_newuid = odn->dn_newuid; 821 ndn->dn_newgid = odn->dn_newgid; 822 ndn->dn_id_flags = odn->dn_id_flags; 823 dmu_zfetch_init(&ndn->dn_zfetch, NULL); 824 list_move_tail(&ndn->dn_zfetch.zf_stream, &odn->dn_zfetch.zf_stream); 825 ndn->dn_zfetch.zf_dnode = odn->dn_zfetch.zf_dnode; 826 827 /* 828 * Update back pointers. Updating the handle fixes the back pointer of 829 * every descendant dbuf as well as the bonus dbuf. 830 */ 831 ASSERT(ndn->dn_handle->dnh_dnode == odn); 832 ndn->dn_handle->dnh_dnode = ndn; 833 if (ndn->dn_zfetch.zf_dnode == odn) { 834 ndn->dn_zfetch.zf_dnode = ndn; 835 } 836 837 /* 838 * Invalidate the original dnode by clearing all of its back pointers. 839 */ 840 odn->dn_dbuf = NULL; 841 odn->dn_handle = NULL; 842 avl_create(&odn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t), 843 offsetof(dmu_buf_impl_t, db_link)); 844 odn->dn_dbufs_count = 0; 845 odn->dn_bonus = NULL; 846 odn->dn_zfetch.zf_dnode = NULL; 847 848 /* 849 * Set the low bit of the objset pointer to ensure that dnode_move() 850 * recognizes the dnode as invalid in any subsequent callback. 851 */ 852 POINTER_INVALIDATE(&odn->dn_objset); 853 854 /* 855 * Satisfy the destructor. 856 */ 857 for (i = 0; i < TXG_SIZE; i++) { 858 list_create(&odn->dn_dirty_records[i], 859 sizeof (dbuf_dirty_record_t), 860 offsetof(dbuf_dirty_record_t, dr_dirty_node)); 861 odn->dn_free_ranges[i] = NULL; 862 odn->dn_next_nlevels[i] = 0; 863 odn->dn_next_indblkshift[i] = 0; 864 odn->dn_next_bonustype[i] = 0; 865 odn->dn_rm_spillblk[i] = 0; 866 odn->dn_next_bonuslen[i] = 0; 867 odn->dn_next_blksz[i] = 0; 868 } 869 odn->dn_allocated_txg = 0; 870 odn->dn_free_txg = 0; 871 odn->dn_assigned_txg = 0; 872 odn->dn_dirtyctx = 0; 873 odn->dn_dirtyctx_firstset = NULL; 874 odn->dn_have_spill = B_FALSE; 875 odn->dn_zio = NULL; 876 odn->dn_oldused = 0; 877 odn->dn_oldflags = 0; 878 odn->dn_olduid = 0; 879 odn->dn_oldgid = 0; 880 odn->dn_newuid = 0; 881 odn->dn_newgid = 0; 882 odn->dn_id_flags = 0; 883 884 /* 885 * Mark the dnode. 886 */ 887 ndn->dn_moved = 1; 888 odn->dn_moved = (uint8_t)-1; 889 } 890 891 /*ARGSUSED*/ 892 static kmem_cbrc_t 893 dnode_move(void *buf, void *newbuf, size_t size, void *arg) 894 { 895 dnode_t *odn = buf, *ndn = newbuf; 896 objset_t *os; 897 int64_t refcount; 898 uint32_t dbufs; 899 900 /* 901 * The dnode is on the objset's list of known dnodes if the objset 902 * pointer is valid. We set the low bit of the objset pointer when 903 * freeing the dnode to invalidate it, and the memory patterns written 904 * by kmem (baddcafe and deadbeef) set at least one of the two low bits. 905 * A newly created dnode sets the objset pointer last of all to indicate 906 * that the dnode is known and in a valid state to be moved by this 907 * function. 908 */ 909 os = odn->dn_objset; 910 if (!POINTER_IS_VALID(os)) { 911 DNODE_STAT_BUMP(dnode_move_invalid); 912 return (KMEM_CBRC_DONT_KNOW); 913 } 914 915 /* 916 * Ensure that the objset does not go away during the move. 917 */ 918 rw_enter(&os_lock, RW_WRITER); 919 if (os != odn->dn_objset) { 920 rw_exit(&os_lock); 921 DNODE_STAT_BUMP(dnode_move_recheck1); 922 return (KMEM_CBRC_DONT_KNOW); 923 } 924 925 /* 926 * If the dnode is still valid, then so is the objset. We know that no 927 * valid objset can be freed while we hold os_lock, so we can safely 928 * ensure that the objset remains in use. 929 */ 930 mutex_enter(&os->os_lock); 931 932 /* 933 * Recheck the objset pointer in case the dnode was removed just before 934 * acquiring the lock. 935 */ 936 if (os != odn->dn_objset) { 937 mutex_exit(&os->os_lock); 938 rw_exit(&os_lock); 939 DNODE_STAT_BUMP(dnode_move_recheck2); 940 return (KMEM_CBRC_DONT_KNOW); 941 } 942 943 /* 944 * At this point we know that as long as we hold os->os_lock, the dnode 945 * cannot be freed and fields within the dnode can be safely accessed. 946 * The objset listing this dnode cannot go away as long as this dnode is 947 * on its list. 948 */ 949 rw_exit(&os_lock); 950 if (DMU_OBJECT_IS_SPECIAL(odn->dn_object)) { 951 mutex_exit(&os->os_lock); 952 DNODE_STAT_BUMP(dnode_move_special); 953 return (KMEM_CBRC_NO); 954 } 955 ASSERT(odn->dn_dbuf != NULL); /* only "special" dnodes have no parent */ 956 957 /* 958 * Lock the dnode handle to prevent the dnode from obtaining any new 959 * holds. This also prevents the descendant dbufs and the bonus dbuf 960 * from accessing the dnode, so that we can discount their holds. The 961 * handle is safe to access because we know that while the dnode cannot 962 * go away, neither can its handle. Once we hold dnh_zrlock, we can 963 * safely move any dnode referenced only by dbufs. 964 */ 965 if (!zrl_tryenter(&odn->dn_handle->dnh_zrlock)) { 966 mutex_exit(&os->os_lock); 967 DNODE_STAT_BUMP(dnode_move_handle); 968 return (KMEM_CBRC_LATER); 969 } 970 971 /* 972 * Ensure a consistent view of the dnode's holds and the dnode's dbufs. 973 * We need to guarantee that there is a hold for every dbuf in order to 974 * determine whether the dnode is actively referenced. Falsely matching 975 * a dbuf to an active hold would lead to an unsafe move. It's possible 976 * that a thread already having an active dnode hold is about to add a 977 * dbuf, and we can't compare hold and dbuf counts while the add is in 978 * progress. 979 */ 980 if (!rw_tryenter(&odn->dn_struct_rwlock, RW_WRITER)) { 981 zrl_exit(&odn->dn_handle->dnh_zrlock); 982 mutex_exit(&os->os_lock); 983 DNODE_STAT_BUMP(dnode_move_rwlock); 984 return (KMEM_CBRC_LATER); 985 } 986 987 /* 988 * A dbuf may be removed (evicted) without an active dnode hold. In that 989 * case, the dbuf count is decremented under the handle lock before the 990 * dbuf's hold is released. This order ensures that if we count the hold 991 * after the dbuf is removed but before its hold is released, we will 992 * treat the unmatched hold as active and exit safely. If we count the 993 * hold before the dbuf is removed, the hold is discounted, and the 994 * removal is blocked until the move completes. 995 */ 996 refcount = refcount_count(&odn->dn_holds); 997 ASSERT(refcount >= 0); 998 dbufs = odn->dn_dbufs_count; 999 1000 /* We can't have more dbufs than dnode holds. */ 1001 ASSERT3U(dbufs, <=, refcount); 1002 DTRACE_PROBE3(dnode__move, dnode_t *, odn, int64_t, refcount, 1003 uint32_t, dbufs); 1004 1005 if (refcount > dbufs) { 1006 rw_exit(&odn->dn_struct_rwlock); 1007 zrl_exit(&odn->dn_handle->dnh_zrlock); 1008 mutex_exit(&os->os_lock); 1009 DNODE_STAT_BUMP(dnode_move_active); 1010 return (KMEM_CBRC_LATER); 1011 } 1012 1013 rw_exit(&odn->dn_struct_rwlock); 1014 1015 /* 1016 * At this point we know that anyone with a hold on the dnode is not 1017 * actively referencing it. The dnode is known and in a valid state to 1018 * move. We're holding the locks needed to execute the critical section. 1019 */ 1020 dnode_move_impl(odn, ndn); 1021 1022 list_link_replace(&odn->dn_link, &ndn->dn_link); 1023 /* If the dnode was safe to move, the refcount cannot have changed. */ 1024 ASSERT(refcount == refcount_count(&ndn->dn_holds)); 1025 ASSERT(dbufs == ndn->dn_dbufs_count); 1026 zrl_exit(&ndn->dn_handle->dnh_zrlock); /* handle has moved */ 1027 mutex_exit(&os->os_lock); 1028 1029 return (KMEM_CBRC_YES); 1030 } 1031 #endif /* _KERNEL */ 1032 1033 static void 1034 dnode_slots_hold(dnode_children_t *children, int idx, int slots) 1035 { 1036 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1037 1038 for (int i = idx; i < idx + slots; i++) { 1039 dnode_handle_t *dnh = &children->dnc_children[i]; 1040 zrl_add(&dnh->dnh_zrlock); 1041 } 1042 } 1043 1044 static void 1045 dnode_slots_rele(dnode_children_t *children, int idx, int slots) 1046 { 1047 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1048 1049 for (int i = idx; i < idx + slots; i++) { 1050 dnode_handle_t *dnh = &children->dnc_children[i]; 1051 1052 if (zrl_is_locked(&dnh->dnh_zrlock)) 1053 zrl_exit(&dnh->dnh_zrlock); 1054 else 1055 zrl_remove(&dnh->dnh_zrlock); 1056 } 1057 } 1058 1059 static int 1060 dnode_slots_tryenter(dnode_children_t *children, int idx, int slots) 1061 { 1062 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1063 1064 for (int i = idx; i < idx + slots; i++) { 1065 dnode_handle_t *dnh = &children->dnc_children[i]; 1066 1067 if (!zrl_tryenter(&dnh->dnh_zrlock)) { 1068 for (int j = idx; j < i; j++) { 1069 dnh = &children->dnc_children[j]; 1070 zrl_exit(&dnh->dnh_zrlock); 1071 } 1072 1073 return (0); 1074 } 1075 } 1076 1077 return (1); 1078 } 1079 1080 static void 1081 dnode_set_slots(dnode_children_t *children, int idx, int slots, void *ptr) 1082 { 1083 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1084 1085 for (int i = idx; i < idx + slots; i++) { 1086 dnode_handle_t *dnh = &children->dnc_children[i]; 1087 dnh->dnh_dnode = ptr; 1088 } 1089 } 1090 1091 static boolean_t 1092 dnode_check_slots_free(dnode_children_t *children, int idx, int slots) 1093 { 1094 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1095 1096 for (int i = idx; i < idx + slots; i++) { 1097 dnode_handle_t *dnh = &children->dnc_children[i]; 1098 dnode_t *dn = dnh->dnh_dnode; 1099 1100 if (dn == DN_SLOT_FREE) { 1101 continue; 1102 } else if (DN_SLOT_IS_PTR(dn)) { 1103 mutex_enter(&dn->dn_mtx); 1104 dmu_object_type_t type = dn->dn_type; 1105 mutex_exit(&dn->dn_mtx); 1106 1107 if (type != DMU_OT_NONE) 1108 return (B_FALSE); 1109 1110 continue; 1111 } else { 1112 return (B_FALSE); 1113 } 1114 1115 return (B_FALSE); 1116 } 1117 1118 return (B_TRUE); 1119 } 1120 1121 static void 1122 dnode_reclaim_slots(dnode_children_t *children, int idx, int slots) 1123 { 1124 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1125 1126 for (int i = idx; i < idx + slots; i++) { 1127 dnode_handle_t *dnh = &children->dnc_children[i]; 1128 1129 ASSERT(zrl_is_locked(&dnh->dnh_zrlock)); 1130 1131 if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { 1132 ASSERT3S(dnh->dnh_dnode->dn_type, ==, DMU_OT_NONE); 1133 dnode_destroy(dnh->dnh_dnode); 1134 dnh->dnh_dnode = DN_SLOT_FREE; 1135 } 1136 } 1137 } 1138 1139 void 1140 dnode_free_interior_slots(dnode_t *dn) 1141 { 1142 dnode_children_t *children = dmu_buf_get_user(&dn->dn_dbuf->db); 1143 int epb = dn->dn_dbuf->db.db_size >> DNODE_SHIFT; 1144 int idx = (dn->dn_object & (epb - 1)) + 1; 1145 int slots = dn->dn_num_slots - 1; 1146 1147 if (slots == 0) 1148 return; 1149 1150 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1151 1152 while (!dnode_slots_tryenter(children, idx, slots)) 1153 DNODE_STAT_BUMP(dnode_free_interior_lock_retry); 1154 1155 dnode_set_slots(children, idx, slots, DN_SLOT_FREE); 1156 dnode_slots_rele(children, idx, slots); 1157 } 1158 1159 void 1160 dnode_special_close(dnode_handle_t *dnh) 1161 { 1162 dnode_t *dn = dnh->dnh_dnode; 1163 1164 /* 1165 * Wait for final references to the dnode to clear. This can 1166 * only happen if the arc is asynchronously evicting state that 1167 * has a hold on this dnode while we are trying to evict this 1168 * dnode. 1169 */ 1170 while (refcount_count(&dn->dn_holds) > 0) 1171 delay(1); 1172 ASSERT(dn->dn_dbuf == NULL || 1173 dmu_buf_get_user(&dn->dn_dbuf->db) == NULL); 1174 zrl_add(&dnh->dnh_zrlock); 1175 dnode_destroy(dn); /* implicit zrl_remove() */ 1176 zrl_destroy(&dnh->dnh_zrlock); 1177 dnh->dnh_dnode = NULL; 1178 } 1179 1180 void 1181 dnode_special_open(objset_t *os, dnode_phys_t *dnp, uint64_t object, 1182 dnode_handle_t *dnh) 1183 { 1184 dnode_t *dn; 1185 1186 zrl_init(&dnh->dnh_zrlock); 1187 zrl_tryenter(&dnh->dnh_zrlock); 1188 1189 dn = dnode_create(os, dnp, NULL, object, dnh); 1190 DNODE_VERIFY(dn); 1191 1192 zrl_exit(&dnh->dnh_zrlock); 1193 } 1194 1195 static void 1196 dnode_buf_evict_async(void *dbu) 1197 { 1198 dnode_children_t *dnc = dbu; 1199 1200 DNODE_STAT_BUMP(dnode_buf_evict); 1201 1202 for (int i = 0; i < dnc->dnc_count; i++) { 1203 dnode_handle_t *dnh = &dnc->dnc_children[i]; 1204 dnode_t *dn; 1205 1206 /* 1207 * The dnode handle lock guards against the dnode moving to 1208 * another valid address, so there is no need here to guard 1209 * against changes to or from NULL. 1210 */ 1211 if (!DN_SLOT_IS_PTR(dnh->dnh_dnode)) { 1212 zrl_destroy(&dnh->dnh_zrlock); 1213 dnh->dnh_dnode = DN_SLOT_UNINIT; 1214 continue; 1215 } 1216 1217 zrl_add(&dnh->dnh_zrlock); 1218 dn = dnh->dnh_dnode; 1219 /* 1220 * If there are holds on this dnode, then there should 1221 * be holds on the dnode's containing dbuf as well; thus 1222 * it wouldn't be eligible for eviction and this function 1223 * would not have been called. 1224 */ 1225 ASSERT(refcount_is_zero(&dn->dn_holds)); 1226 ASSERT(refcount_is_zero(&dn->dn_tx_holds)); 1227 1228 dnode_destroy(dn); /* implicit zrl_remove() for first slot */ 1229 zrl_destroy(&dnh->dnh_zrlock); 1230 dnh->dnh_dnode = DN_SLOT_UNINIT; 1231 } 1232 kmem_free(dnc, sizeof (dnode_children_t) + 1233 dnc->dnc_count * sizeof (dnode_handle_t)); 1234 } 1235 1236 /* 1237 * When the DNODE_MUST_BE_FREE flag is set, the "slots" parameter is used 1238 * to ensure the hole at the specified object offset is large enough to 1239 * hold the dnode being created. The slots parameter is also used to ensure 1240 * a dnode does not span multiple dnode blocks. In both of these cases, if 1241 * a failure occurs, ENOSPC is returned. Keep in mind, these failure cases 1242 * are only possible when using DNODE_MUST_BE_FREE. 1243 * 1244 * If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. 1245 * dnode_hold_impl() will check if the requested dnode is already consumed 1246 * as an extra dnode slot by an large dnode, in which case it returns 1247 * ENOENT. 1248 * 1249 * errors: 1250 * EINVAL - invalid object number or flags. 1251 * ENOSPC - hole too small to fulfill "slots" request (DNODE_MUST_BE_FREE) 1252 * EEXIST - Refers to an allocated dnode (DNODE_MUST_BE_FREE) 1253 * - Refers to a freeing dnode (DNODE_MUST_BE_FREE) 1254 * - Refers to an interior dnode slot (DNODE_MUST_BE_ALLOCATED) 1255 * ENOENT - The requested dnode is not allocated (DNODE_MUST_BE_ALLOCATED) 1256 * - The requested dnode is being freed (DNODE_MUST_BE_ALLOCATED) 1257 * EIO - i/o error error when reading the meta dnode dbuf. 1258 * succeeds even for free dnodes. 1259 */ 1260 int 1261 dnode_hold_impl(objset_t *os, uint64_t object, int flag, int slots, 1262 void *tag, dnode_t **dnp) 1263 { 1264 int epb, idx, err; 1265 int drop_struct_lock = FALSE; 1266 int type; 1267 uint64_t blk; 1268 dnode_t *mdn, *dn; 1269 dmu_buf_impl_t *db; 1270 dnode_children_t *dnc; 1271 dnode_phys_t *dn_block; 1272 dnode_handle_t *dnh; 1273 1274 ASSERT(!(flag & DNODE_MUST_BE_ALLOCATED) || (slots == 0)); 1275 ASSERT(!(flag & DNODE_MUST_BE_FREE) || (slots > 0)); 1276 1277 /* 1278 * If you are holding the spa config lock as writer, you shouldn't 1279 * be asking the DMU to do *anything* unless it's the root pool 1280 * which may require us to read from the root filesystem while 1281 * holding some (not all) of the locks as writer. 1282 */ 1283 ASSERT(spa_config_held(os->os_spa, SCL_ALL, RW_WRITER) == 0 || 1284 (spa_is_root(os->os_spa) && 1285 spa_config_held(os->os_spa, SCL_STATE, RW_WRITER))); 1286 1287 ASSERT((flag & DNODE_MUST_BE_ALLOCATED) || (flag & DNODE_MUST_BE_FREE)); 1288 1289 if (object == DMU_USERUSED_OBJECT || object == DMU_GROUPUSED_OBJECT) { 1290 dn = (object == DMU_USERUSED_OBJECT) ? 1291 DMU_USERUSED_DNODE(os) : DMU_GROUPUSED_DNODE(os); 1292 if (dn == NULL) 1293 return (SET_ERROR(ENOENT)); 1294 type = dn->dn_type; 1295 if ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE) 1296 return (SET_ERROR(ENOENT)); 1297 if ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE) 1298 return (SET_ERROR(EEXIST)); 1299 DNODE_VERIFY(dn); 1300 (void) refcount_add(&dn->dn_holds, tag); 1301 *dnp = dn; 1302 return (0); 1303 } 1304 1305 if (object == 0 || object >= DN_MAX_OBJECT) 1306 return (SET_ERROR(EINVAL)); 1307 1308 mdn = DMU_META_DNODE(os); 1309 ASSERT(mdn->dn_object == DMU_META_DNODE_OBJECT); 1310 1311 DNODE_VERIFY(mdn); 1312 1313 if (!RW_WRITE_HELD(&mdn->dn_struct_rwlock)) { 1314 rw_enter(&mdn->dn_struct_rwlock, RW_READER); 1315 drop_struct_lock = TRUE; 1316 } 1317 1318 blk = dbuf_whichblock(mdn, 0, object * sizeof (dnode_phys_t)); 1319 1320 db = dbuf_hold(mdn, blk, FTAG); 1321 if (drop_struct_lock) 1322 rw_exit(&mdn->dn_struct_rwlock); 1323 if (db == NULL) { 1324 DNODE_STAT_BUMP(dnode_hold_dbuf_hold); 1325 return (SET_ERROR(EIO)); 1326 } 1327 err = dbuf_read(db, NULL, DB_RF_CANFAIL); 1328 if (err) { 1329 DNODE_STAT_BUMP(dnode_hold_dbuf_read); 1330 dbuf_rele(db, FTAG); 1331 return (err); 1332 } 1333 1334 ASSERT3U(db->db.db_size, >=, 1<<DNODE_SHIFT); 1335 epb = db->db.db_size >> DNODE_SHIFT; 1336 1337 idx = object & (epb - 1); 1338 dn_block = (dnode_phys_t *)db->db.db_data; 1339 1340 ASSERT(DB_DNODE(db)->dn_type == DMU_OT_DNODE); 1341 dnc = dmu_buf_get_user(&db->db); 1342 dnh = NULL; 1343 if (dnc == NULL) { 1344 dnode_children_t *winner; 1345 int skip = 0; 1346 1347 dnc = kmem_zalloc(sizeof (dnode_children_t) + 1348 epb * sizeof (dnode_handle_t), KM_SLEEP); 1349 dnc->dnc_count = epb; 1350 dnh = &dnc->dnc_children[0]; 1351 1352 /* Initialize dnode slot status from dnode_phys_t */ 1353 for (int i = 0; i < epb; i++) { 1354 zrl_init(&dnh[i].dnh_zrlock); 1355 1356 if (skip) { 1357 skip--; 1358 continue; 1359 } 1360 1361 if (dn_block[i].dn_type != DMU_OT_NONE) { 1362 int interior = dn_block[i].dn_extra_slots; 1363 1364 dnode_set_slots(dnc, i, 1, DN_SLOT_ALLOCATED); 1365 dnode_set_slots(dnc, i + 1, interior, 1366 DN_SLOT_INTERIOR); 1367 skip = interior; 1368 } else { 1369 dnh[i].dnh_dnode = DN_SLOT_FREE; 1370 skip = 0; 1371 } 1372 } 1373 1374 dmu_buf_init_user(&dnc->dnc_dbu, NULL, 1375 dnode_buf_evict_async, NULL); 1376 winner = dmu_buf_set_user(&db->db, &dnc->dnc_dbu); 1377 if (winner != NULL) { 1378 1379 for (int i = 0; i < epb; i++) 1380 zrl_destroy(&dnh[i].dnh_zrlock); 1381 1382 kmem_free(dnc, sizeof (dnode_children_t) + 1383 epb * sizeof (dnode_handle_t)); 1384 dnc = winner; 1385 } 1386 } 1387 1388 ASSERT(dnc->dnc_count == epb); 1389 dn = DN_SLOT_UNINIT; 1390 1391 if (flag & DNODE_MUST_BE_ALLOCATED) { 1392 slots = 1; 1393 1394 while (dn == DN_SLOT_UNINIT) { 1395 dnode_slots_hold(dnc, idx, slots); 1396 dnh = &dnc->dnc_children[idx]; 1397 1398 if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { 1399 dn = dnh->dnh_dnode; 1400 break; 1401 } else if (dnh->dnh_dnode == DN_SLOT_INTERIOR) { 1402 DNODE_STAT_BUMP(dnode_hold_alloc_interior); 1403 dnode_slots_rele(dnc, idx, slots); 1404 dbuf_rele(db, FTAG); 1405 return (SET_ERROR(EEXIST)); 1406 } else if (dnh->dnh_dnode != DN_SLOT_ALLOCATED) { 1407 DNODE_STAT_BUMP(dnode_hold_alloc_misses); 1408 dnode_slots_rele(dnc, idx, slots); 1409 dbuf_rele(db, FTAG); 1410 return (SET_ERROR(ENOENT)); 1411 } 1412 1413 dnode_slots_rele(dnc, idx, slots); 1414 if (!dnode_slots_tryenter(dnc, idx, slots)) { 1415 DNODE_STAT_BUMP(dnode_hold_alloc_lock_retry); 1416 continue; 1417 } 1418 1419 /* 1420 * Someone else won the race and called dnode_create() 1421 * after we checked DN_SLOT_IS_PTR() above but before 1422 * we acquired the lock. 1423 */ 1424 if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { 1425 DNODE_STAT_BUMP(dnode_hold_alloc_lock_misses); 1426 dn = dnh->dnh_dnode; 1427 } else { 1428 dn = dnode_create(os, dn_block + idx, db, 1429 object, dnh); 1430 } 1431 } 1432 1433 mutex_enter(&dn->dn_mtx); 1434 if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg != 0) { 1435 DNODE_STAT_BUMP(dnode_hold_alloc_type_none); 1436 mutex_exit(&dn->dn_mtx); 1437 dnode_slots_rele(dnc, idx, slots); 1438 dbuf_rele(db, FTAG); 1439 return (SET_ERROR(ENOENT)); 1440 } 1441 1442 DNODE_STAT_BUMP(dnode_hold_alloc_hits); 1443 } else if (flag & DNODE_MUST_BE_FREE) { 1444 1445 if (idx + slots - 1 >= DNODES_PER_BLOCK) { 1446 DNODE_STAT_BUMP(dnode_hold_free_overflow); 1447 dbuf_rele(db, FTAG); 1448 return (SET_ERROR(ENOSPC)); 1449 } 1450 1451 while (dn == DN_SLOT_UNINIT) { 1452 dnode_slots_hold(dnc, idx, slots); 1453 1454 if (!dnode_check_slots_free(dnc, idx, slots)) { 1455 DNODE_STAT_BUMP(dnode_hold_free_misses); 1456 dnode_slots_rele(dnc, idx, slots); 1457 dbuf_rele(db, FTAG); 1458 return (SET_ERROR(ENOSPC)); 1459 } 1460 1461 dnode_slots_rele(dnc, idx, slots); 1462 if (!dnode_slots_tryenter(dnc, idx, slots)) { 1463 DNODE_STAT_BUMP(dnode_hold_free_lock_retry); 1464 continue; 1465 } 1466 1467 if (!dnode_check_slots_free(dnc, idx, slots)) { 1468 DNODE_STAT_BUMP(dnode_hold_free_lock_misses); 1469 dnode_slots_rele(dnc, idx, slots); 1470 dbuf_rele(db, FTAG); 1471 return (SET_ERROR(ENOSPC)); 1472 } 1473 1474 /* 1475 * Allocated but otherwise free dnodes which would 1476 * be in the interior of a multi-slot dnodes need 1477 * to be freed. Single slot dnodes can be safely 1478 * re-purposed as a performance optimization. 1479 */ 1480 if (slots > 1) 1481 dnode_reclaim_slots(dnc, idx + 1, slots - 1); 1482 1483 dnh = &dnc->dnc_children[idx]; 1484 if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { 1485 dn = dnh->dnh_dnode; 1486 } else { 1487 dn = dnode_create(os, dn_block + idx, db, 1488 object, dnh); 1489 } 1490 } 1491 1492 mutex_enter(&dn->dn_mtx); 1493 if (!refcount_is_zero(&dn->dn_holds) || dn->dn_free_txg) { 1494 DNODE_STAT_BUMP(dnode_hold_free_refcount); 1495 mutex_exit(&dn->dn_mtx); 1496 dnode_slots_rele(dnc, idx, slots); 1497 dbuf_rele(db, FTAG); 1498 return (SET_ERROR(EEXIST)); 1499 } 1500 1501 dnode_set_slots(dnc, idx + 1, slots - 1, DN_SLOT_INTERIOR); 1502 DNODE_STAT_BUMP(dnode_hold_free_hits); 1503 } else { 1504 dbuf_rele(db, FTAG); 1505 return (SET_ERROR(EINVAL)); 1506 } 1507 1508 if (dn->dn_free_txg) { 1509 DNODE_STAT_BUMP(dnode_hold_free_txg); 1510 type = dn->dn_type; 1511 mutex_exit(&dn->dn_mtx); 1512 dnode_slots_rele(dnc, idx, slots); 1513 dbuf_rele(db, FTAG); 1514 return (SET_ERROR((flag & DNODE_MUST_BE_ALLOCATED) ? 1515 ENOENT : EEXIST)); 1516 } 1517 1518 if (refcount_add(&dn->dn_holds, tag) == 1) 1519 dbuf_add_ref(db, dnh); 1520 1521 mutex_exit(&dn->dn_mtx); 1522 1523 /* Now we can rely on the hold to prevent the dnode from moving. */ 1524 dnode_slots_rele(dnc, idx, slots); 1525 1526 DNODE_VERIFY(dn); 1527 ASSERT3P(dn->dn_dbuf, ==, db); 1528 ASSERT3U(dn->dn_object, ==, object); 1529 dbuf_rele(db, FTAG); 1530 1531 *dnp = dn; 1532 return (0); 1533 } 1534 1535 /* 1536 * Return held dnode if the object is allocated, NULL if not. 1537 */ 1538 int 1539 dnode_hold(objset_t *os, uint64_t object, void *tag, dnode_t **dnp) 1540 { 1541 return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, 0, tag, 1542 dnp)); 1543 } 1544 1545 /* 1546 * Can only add a reference if there is already at least one 1547 * reference on the dnode. Returns FALSE if unable to add a 1548 * new reference. 1549 */ 1550 boolean_t 1551 dnode_add_ref(dnode_t *dn, void *tag) 1552 { 1553 mutex_enter(&dn->dn_mtx); 1554 if (refcount_is_zero(&dn->dn_holds)) { 1555 mutex_exit(&dn->dn_mtx); 1556 return (FALSE); 1557 } 1558 VERIFY(1 < refcount_add(&dn->dn_holds, tag)); 1559 mutex_exit(&dn->dn_mtx); 1560 return (TRUE); 1561 } 1562 1563 void 1564 dnode_rele(dnode_t *dn, void *tag) 1565 { 1566 mutex_enter(&dn->dn_mtx); 1567 dnode_rele_and_unlock(dn, tag, B_FALSE); 1568 } 1569 1570 void 1571 dnode_rele_and_unlock(dnode_t *dn, void *tag, boolean_t evicting) 1572 { 1573 uint64_t refs; 1574 /* Get while the hold prevents the dnode from moving. */ 1575 dmu_buf_impl_t *db = dn->dn_dbuf; 1576 dnode_handle_t *dnh = dn->dn_handle; 1577 1578 refs = refcount_remove(&dn->dn_holds, tag); 1579 mutex_exit(&dn->dn_mtx); 1580 1581 /* 1582 * It's unsafe to release the last hold on a dnode by dnode_rele() or 1583 * indirectly by dbuf_rele() while relying on the dnode handle to 1584 * prevent the dnode from moving, since releasing the last hold could 1585 * result in the dnode's parent dbuf evicting its dnode handles. For 1586 * that reason anyone calling dnode_rele() or dbuf_rele() without some 1587 * other direct or indirect hold on the dnode must first drop the dnode 1588 * handle. 1589 */ 1590 ASSERT(refs > 0 || dnh->dnh_zrlock.zr_owner != curthread); 1591 1592 /* NOTE: the DNODE_DNODE does not have a dn_dbuf */ 1593 if (refs == 0 && db != NULL) { 1594 /* 1595 * Another thread could add a hold to the dnode handle in 1596 * dnode_hold_impl() while holding the parent dbuf. Since the 1597 * hold on the parent dbuf prevents the handle from being 1598 * destroyed, the hold on the handle is OK. We can't yet assert 1599 * that the handle has zero references, but that will be 1600 * asserted anyway when the handle gets destroyed. 1601 */ 1602 mutex_enter(&db->db_mtx); 1603 dbuf_rele_and_unlock(db, dnh, evicting); 1604 } 1605 } 1606 1607 void 1608 dnode_setdirty(dnode_t *dn, dmu_tx_t *tx) 1609 { 1610 objset_t *os = dn->dn_objset; 1611 uint64_t txg = tx->tx_txg; 1612 1613 if (DMU_OBJECT_IS_SPECIAL(dn->dn_object)) { 1614 dsl_dataset_dirty(os->os_dsl_dataset, tx); 1615 return; 1616 } 1617 1618 DNODE_VERIFY(dn); 1619 1620 #ifdef ZFS_DEBUG 1621 mutex_enter(&dn->dn_mtx); 1622 ASSERT(dn->dn_phys->dn_type || dn->dn_allocated_txg); 1623 ASSERT(dn->dn_free_txg == 0 || dn->dn_free_txg >= txg); 1624 mutex_exit(&dn->dn_mtx); 1625 #endif 1626 1627 /* 1628 * Determine old uid/gid when necessary 1629 */ 1630 dmu_objset_userquota_get_ids(dn, B_TRUE, tx); 1631 1632 multilist_t *dirtylist = os->os_dirty_dnodes[txg & TXG_MASK]; 1633 multilist_sublist_t *mls = multilist_sublist_lock_obj(dirtylist, dn); 1634 1635 /* 1636 * If we are already marked dirty, we're done. 1637 */ 1638 if (list_link_active(&dn->dn_dirty_link[txg & TXG_MASK])) { 1639 multilist_sublist_unlock(mls); 1640 return; 1641 } 1642 1643 ASSERT(!refcount_is_zero(&dn->dn_holds) || 1644 !avl_is_empty(&dn->dn_dbufs)); 1645 ASSERT(dn->dn_datablksz != 0); 1646 ASSERT0(dn->dn_next_bonuslen[txg&TXG_MASK]); 1647 ASSERT0(dn->dn_next_blksz[txg&TXG_MASK]); 1648 ASSERT0(dn->dn_next_bonustype[txg&TXG_MASK]); 1649 1650 dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n", 1651 dn->dn_object, txg); 1652 1653 multilist_sublist_insert_head(mls, dn); 1654 1655 multilist_sublist_unlock(mls); 1656 1657 /* 1658 * The dnode maintains a hold on its containing dbuf as 1659 * long as there are holds on it. Each instantiated child 1660 * dbuf maintains a hold on the dnode. When the last child 1661 * drops its hold, the dnode will drop its hold on the 1662 * containing dbuf. We add a "dirty hold" here so that the 1663 * dnode will hang around after we finish processing its 1664 * children. 1665 */ 1666 VERIFY(dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg)); 1667 1668 (void) dbuf_dirty(dn->dn_dbuf, tx); 1669 1670 dsl_dataset_dirty(os->os_dsl_dataset, tx); 1671 } 1672 1673 void 1674 dnode_free(dnode_t *dn, dmu_tx_t *tx) 1675 { 1676 mutex_enter(&dn->dn_mtx); 1677 if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg) { 1678 mutex_exit(&dn->dn_mtx); 1679 return; 1680 } 1681 dn->dn_free_txg = tx->tx_txg; 1682 mutex_exit(&dn->dn_mtx); 1683 1684 dnode_setdirty(dn, tx); 1685 } 1686 1687 /* 1688 * Try to change the block size for the indicated dnode. This can only 1689 * succeed if there are no blocks allocated or dirty beyond first block 1690 */ 1691 int 1692 dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx) 1693 { 1694 dmu_buf_impl_t *db; 1695 int err; 1696 1697 ASSERT3U(size, <=, spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); 1698 if (size == 0) 1699 size = SPA_MINBLOCKSIZE; 1700 else 1701 size = P2ROUNDUP(size, SPA_MINBLOCKSIZE); 1702 1703 if (ibs == dn->dn_indblkshift) 1704 ibs = 0; 1705 1706 if (size >> SPA_MINBLOCKSHIFT == dn->dn_datablkszsec && ibs == 0) 1707 return (0); 1708 1709 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 1710 1711 /* Check for any allocated blocks beyond the first */ 1712 if (dn->dn_maxblkid != 0) 1713 goto fail; 1714 1715 mutex_enter(&dn->dn_dbufs_mtx); 1716 for (db = avl_first(&dn->dn_dbufs); db != NULL; 1717 db = AVL_NEXT(&dn->dn_dbufs, db)) { 1718 if (db->db_blkid != 0 && db->db_blkid != DMU_BONUS_BLKID && 1719 db->db_blkid != DMU_SPILL_BLKID) { 1720 mutex_exit(&dn->dn_dbufs_mtx); 1721 goto fail; 1722 } 1723 } 1724 mutex_exit(&dn->dn_dbufs_mtx); 1725 1726 if (ibs && dn->dn_nlevels != 1) 1727 goto fail; 1728 1729 /* resize the old block */ 1730 err = dbuf_hold_impl(dn, 0, 0, TRUE, FALSE, FTAG, &db); 1731 if (err == 0) 1732 dbuf_new_size(db, size, tx); 1733 else if (err != ENOENT) 1734 goto fail; 1735 1736 dnode_setdblksz(dn, size); 1737 dnode_setdirty(dn, tx); 1738 dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = size; 1739 if (ibs) { 1740 dn->dn_indblkshift = ibs; 1741 dn->dn_next_indblkshift[tx->tx_txg&TXG_MASK] = ibs; 1742 } 1743 /* rele after we have fixed the blocksize in the dnode */ 1744 if (db) 1745 dbuf_rele(db, FTAG); 1746 1747 rw_exit(&dn->dn_struct_rwlock); 1748 return (0); 1749 1750 fail: 1751 rw_exit(&dn->dn_struct_rwlock); 1752 return (SET_ERROR(ENOTSUP)); 1753 } 1754 1755 /* read-holding callers must not rely on the lock being continuously held */ 1756 void 1757 dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx, boolean_t have_read) 1758 { 1759 uint64_t txgoff = tx->tx_txg & TXG_MASK; 1760 int epbs, new_nlevels; 1761 uint64_t sz; 1762 1763 ASSERT(blkid != DMU_BONUS_BLKID); 1764 1765 ASSERT(have_read ? 1766 RW_READ_HELD(&dn->dn_struct_rwlock) : 1767 RW_WRITE_HELD(&dn->dn_struct_rwlock)); 1768 1769 /* 1770 * if we have a read-lock, check to see if we need to do any work 1771 * before upgrading to a write-lock. 1772 */ 1773 if (have_read) { 1774 if (blkid <= dn->dn_maxblkid) 1775 return; 1776 1777 if (!rw_tryupgrade(&dn->dn_struct_rwlock)) { 1778 rw_exit(&dn->dn_struct_rwlock); 1779 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 1780 } 1781 } 1782 1783 if (blkid <= dn->dn_maxblkid) 1784 goto out; 1785 1786 dn->dn_maxblkid = blkid; 1787 1788 /* 1789 * Compute the number of levels necessary to support the new maxblkid. 1790 */ 1791 new_nlevels = 1; 1792 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1793 for (sz = dn->dn_nblkptr; 1794 sz <= blkid && sz >= dn->dn_nblkptr; sz <<= epbs) 1795 new_nlevels++; 1796 1797 if (new_nlevels > dn->dn_nlevels) { 1798 int old_nlevels = dn->dn_nlevels; 1799 dmu_buf_impl_t *db; 1800 list_t *list; 1801 dbuf_dirty_record_t *new, *dr, *dr_next; 1802 1803 dn->dn_nlevels = new_nlevels; 1804 1805 ASSERT3U(new_nlevels, >, dn->dn_next_nlevels[txgoff]); 1806 dn->dn_next_nlevels[txgoff] = new_nlevels; 1807 1808 /* dirty the left indirects */ 1809 db = dbuf_hold_level(dn, old_nlevels, 0, FTAG); 1810 ASSERT(db != NULL); 1811 new = dbuf_dirty(db, tx); 1812 dbuf_rele(db, FTAG); 1813 1814 /* transfer the dirty records to the new indirect */ 1815 mutex_enter(&dn->dn_mtx); 1816 mutex_enter(&new->dt.di.dr_mtx); 1817 list = &dn->dn_dirty_records[txgoff]; 1818 for (dr = list_head(list); dr; dr = dr_next) { 1819 dr_next = list_next(&dn->dn_dirty_records[txgoff], dr); 1820 if (dr->dr_dbuf->db_level != new_nlevels-1 && 1821 dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID && 1822 dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) { 1823 ASSERT(dr->dr_dbuf->db_level == old_nlevels-1); 1824 list_remove(&dn->dn_dirty_records[txgoff], dr); 1825 list_insert_tail(&new->dt.di.dr_children, dr); 1826 dr->dr_parent = new; 1827 } 1828 } 1829 mutex_exit(&new->dt.di.dr_mtx); 1830 mutex_exit(&dn->dn_mtx); 1831 } 1832 1833 out: 1834 if (have_read) 1835 rw_downgrade(&dn->dn_struct_rwlock); 1836 } 1837 1838 static void 1839 dnode_dirty_l1(dnode_t *dn, uint64_t l1blkid, dmu_tx_t *tx) 1840 { 1841 dmu_buf_impl_t *db = dbuf_hold_level(dn, 1, l1blkid, FTAG); 1842 if (db != NULL) { 1843 dmu_buf_will_dirty(&db->db, tx); 1844 dbuf_rele(db, FTAG); 1845 } 1846 } 1847 1848 /* 1849 * Dirty all the in-core level-1 dbufs in the range specified by start_blkid 1850 * and end_blkid. 1851 */ 1852 static void 1853 dnode_dirty_l1range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, 1854 dmu_tx_t *tx) 1855 { 1856 dmu_buf_impl_t db_search; 1857 dmu_buf_impl_t *db; 1858 avl_index_t where; 1859 1860 mutex_enter(&dn->dn_dbufs_mtx); 1861 1862 db_search.db_level = 1; 1863 db_search.db_blkid = start_blkid + 1; 1864 db_search.db_state = DB_SEARCH; 1865 for (;;) { 1866 1867 db = avl_find(&dn->dn_dbufs, &db_search, &where); 1868 if (db == NULL) 1869 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 1870 1871 if (db == NULL || db->db_level != 1 || 1872 db->db_blkid >= end_blkid) { 1873 break; 1874 } 1875 1876 /* 1877 * Setup the next blkid we want to search for. 1878 */ 1879 db_search.db_blkid = db->db_blkid + 1; 1880 ASSERT3U(db->db_blkid, >=, start_blkid); 1881 1882 /* 1883 * If the dbuf transitions to DB_EVICTING while we're trying 1884 * to dirty it, then we will be unable to discover it in 1885 * the dbuf hash table. This will result in a call to 1886 * dbuf_create() which needs to acquire the dn_dbufs_mtx 1887 * lock. To avoid a deadlock, we drop the lock before 1888 * dirtying the level-1 dbuf. 1889 */ 1890 mutex_exit(&dn->dn_dbufs_mtx); 1891 dnode_dirty_l1(dn, db->db_blkid, tx); 1892 mutex_enter(&dn->dn_dbufs_mtx); 1893 } 1894 1895 #ifdef ZFS_DEBUG 1896 /* 1897 * Walk all the in-core level-1 dbufs and verify they have been dirtied. 1898 */ 1899 db_search.db_level = 1; 1900 db_search.db_blkid = start_blkid + 1; 1901 db_search.db_state = DB_SEARCH; 1902 db = avl_find(&dn->dn_dbufs, &db_search, &where); 1903 if (db == NULL) 1904 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 1905 for (; db != NULL; db = AVL_NEXT(&dn->dn_dbufs, db)) { 1906 if (db->db_level != 1 || db->db_blkid >= end_blkid) 1907 break; 1908 ASSERT(db->db_dirtycnt > 0); 1909 } 1910 #endif 1911 mutex_exit(&dn->dn_dbufs_mtx); 1912 } 1913 1914 void 1915 dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx) 1916 { 1917 dmu_buf_impl_t *db; 1918 uint64_t blkoff, blkid, nblks; 1919 int blksz, blkshift, head, tail; 1920 int trunc = FALSE; 1921 int epbs; 1922 1923 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 1924 blksz = dn->dn_datablksz; 1925 blkshift = dn->dn_datablkshift; 1926 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1927 1928 if (len == DMU_OBJECT_END) { 1929 len = UINT64_MAX - off; 1930 trunc = TRUE; 1931 } 1932 1933 /* 1934 * First, block align the region to free: 1935 */ 1936 if (ISP2(blksz)) { 1937 head = P2NPHASE(off, blksz); 1938 blkoff = P2PHASE(off, blksz); 1939 if ((off >> blkshift) > dn->dn_maxblkid) 1940 goto out; 1941 } else { 1942 ASSERT(dn->dn_maxblkid == 0); 1943 if (off == 0 && len >= blksz) { 1944 /* 1945 * Freeing the whole block; fast-track this request. 1946 */ 1947 blkid = 0; 1948 nblks = 1; 1949 if (dn->dn_nlevels > 1) 1950 dnode_dirty_l1(dn, 0, tx); 1951 goto done; 1952 } else if (off >= blksz) { 1953 /* Freeing past end-of-data */ 1954 goto out; 1955 } else { 1956 /* Freeing part of the block. */ 1957 head = blksz - off; 1958 ASSERT3U(head, >, 0); 1959 } 1960 blkoff = off; 1961 } 1962 /* zero out any partial block data at the start of the range */ 1963 if (head) { 1964 ASSERT3U(blkoff + head, ==, blksz); 1965 if (len < head) 1966 head = len; 1967 if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off), 1968 TRUE, FALSE, FTAG, &db) == 0) { 1969 caddr_t data; 1970 1971 /* don't dirty if it isn't on disk and isn't dirty */ 1972 if (db->db_last_dirty || 1973 (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) { 1974 rw_exit(&dn->dn_struct_rwlock); 1975 dmu_buf_will_dirty(&db->db, tx); 1976 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 1977 data = db->db.db_data; 1978 bzero(data + blkoff, head); 1979 } 1980 dbuf_rele(db, FTAG); 1981 } 1982 off += head; 1983 len -= head; 1984 } 1985 1986 /* If the range was less than one block, we're done */ 1987 if (len == 0) 1988 goto out; 1989 1990 /* If the remaining range is past end of file, we're done */ 1991 if ((off >> blkshift) > dn->dn_maxblkid) 1992 goto out; 1993 1994 ASSERT(ISP2(blksz)); 1995 if (trunc) 1996 tail = 0; 1997 else 1998 tail = P2PHASE(len, blksz); 1999 2000 ASSERT0(P2PHASE(off, blksz)); 2001 /* zero out any partial block data at the end of the range */ 2002 if (tail) { 2003 if (len < tail) 2004 tail = len; 2005 if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off+len), 2006 TRUE, FALSE, FTAG, &db) == 0) { 2007 /* don't dirty if not on disk and not dirty */ 2008 if (db->db_last_dirty || 2009 (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) { 2010 rw_exit(&dn->dn_struct_rwlock); 2011 dmu_buf_will_dirty(&db->db, tx); 2012 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 2013 bzero(db->db.db_data, tail); 2014 } 2015 dbuf_rele(db, FTAG); 2016 } 2017 len -= tail; 2018 } 2019 2020 /* If the range did not include a full block, we are done */ 2021 if (len == 0) 2022 goto out; 2023 2024 ASSERT(IS_P2ALIGNED(off, blksz)); 2025 ASSERT(trunc || IS_P2ALIGNED(len, blksz)); 2026 blkid = off >> blkshift; 2027 nblks = len >> blkshift; 2028 if (trunc) 2029 nblks += 1; 2030 2031 /* 2032 * Dirty all the indirect blocks in this range. Note that only 2033 * the first and last indirect blocks can actually be written 2034 * (if they were partially freed) -- they must be dirtied, even if 2035 * they do not exist on disk yet. The interior blocks will 2036 * be freed by free_children(), so they will not actually be written. 2037 * Even though these interior blocks will not be written, we 2038 * dirty them for two reasons: 2039 * 2040 * - It ensures that the indirect blocks remain in memory until 2041 * syncing context. (They have already been prefetched by 2042 * dmu_tx_hold_free(), so we don't have to worry about reading 2043 * them serially here.) 2044 * 2045 * - The dirty space accounting will put pressure on the txg sync 2046 * mechanism to begin syncing, and to delay transactions if there 2047 * is a large amount of freeing. Even though these indirect 2048 * blocks will not be written, we could need to write the same 2049 * amount of space if we copy the freed BPs into deadlists. 2050 */ 2051 if (dn->dn_nlevels > 1) { 2052 uint64_t first, last; 2053 2054 first = blkid >> epbs; 2055 dnode_dirty_l1(dn, first, tx); 2056 if (trunc) 2057 last = dn->dn_maxblkid >> epbs; 2058 else 2059 last = (blkid + nblks - 1) >> epbs; 2060 if (last != first) 2061 dnode_dirty_l1(dn, last, tx); 2062 2063 dnode_dirty_l1range(dn, first, last, tx); 2064 2065 int shift = dn->dn_datablkshift + dn->dn_indblkshift - 2066 SPA_BLKPTRSHIFT; 2067 for (uint64_t i = first + 1; i < last; i++) { 2068 /* 2069 * Set i to the blockid of the next non-hole 2070 * level-1 indirect block at or after i. Note 2071 * that dnode_next_offset() operates in terms of 2072 * level-0-equivalent bytes. 2073 */ 2074 uint64_t ibyte = i << shift; 2075 int err = dnode_next_offset(dn, DNODE_FIND_HAVELOCK, 2076 &ibyte, 2, 1, 0); 2077 i = ibyte >> shift; 2078 if (i >= last) 2079 break; 2080 2081 /* 2082 * Normally we should not see an error, either 2083 * from dnode_next_offset() or dbuf_hold_level() 2084 * (except for ESRCH from dnode_next_offset). 2085 * If there is an i/o error, then when we read 2086 * this block in syncing context, it will use 2087 * ZIO_FLAG_MUSTSUCCEED, and thus hang/panic according 2088 * to the "failmode" property. dnode_next_offset() 2089 * doesn't have a flag to indicate MUSTSUCCEED. 2090 */ 2091 if (err != 0) 2092 break; 2093 2094 dnode_dirty_l1(dn, i, tx); 2095 } 2096 } 2097 2098 done: 2099 /* 2100 * Add this range to the dnode range list. 2101 * We will finish up this free operation in the syncing phase. 2102 */ 2103 mutex_enter(&dn->dn_mtx); 2104 int txgoff = tx->tx_txg & TXG_MASK; 2105 if (dn->dn_free_ranges[txgoff] == NULL) { 2106 dn->dn_free_ranges[txgoff] = range_tree_create(NULL, NULL); 2107 } 2108 range_tree_clear(dn->dn_free_ranges[txgoff], blkid, nblks); 2109 range_tree_add(dn->dn_free_ranges[txgoff], blkid, nblks); 2110 dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n", 2111 blkid, nblks, tx->tx_txg); 2112 mutex_exit(&dn->dn_mtx); 2113 2114 dbuf_free_range(dn, blkid, blkid + nblks - 1, tx); 2115 dnode_setdirty(dn, tx); 2116 out: 2117 2118 rw_exit(&dn->dn_struct_rwlock); 2119 } 2120 2121 static boolean_t 2122 dnode_spill_freed(dnode_t *dn) 2123 { 2124 int i; 2125 2126 mutex_enter(&dn->dn_mtx); 2127 for (i = 0; i < TXG_SIZE; i++) { 2128 if (dn->dn_rm_spillblk[i] == DN_KILL_SPILLBLK) 2129 break; 2130 } 2131 mutex_exit(&dn->dn_mtx); 2132 return (i < TXG_SIZE); 2133 } 2134 2135 /* return TRUE if this blkid was freed in a recent txg, or FALSE if it wasn't */ 2136 uint64_t 2137 dnode_block_freed(dnode_t *dn, uint64_t blkid) 2138 { 2139 void *dp = spa_get_dsl(dn->dn_objset->os_spa); 2140 int i; 2141 2142 if (blkid == DMU_BONUS_BLKID) 2143 return (FALSE); 2144 2145 /* 2146 * If we're in the process of opening the pool, dp will not be 2147 * set yet, but there shouldn't be anything dirty. 2148 */ 2149 if (dp == NULL) 2150 return (FALSE); 2151 2152 if (dn->dn_free_txg) 2153 return (TRUE); 2154 2155 if (blkid == DMU_SPILL_BLKID) 2156 return (dnode_spill_freed(dn)); 2157 2158 mutex_enter(&dn->dn_mtx); 2159 for (i = 0; i < TXG_SIZE; i++) { 2160 if (dn->dn_free_ranges[i] != NULL && 2161 range_tree_contains(dn->dn_free_ranges[i], blkid, 1)) 2162 break; 2163 } 2164 mutex_exit(&dn->dn_mtx); 2165 return (i < TXG_SIZE); 2166 } 2167 2168 /* call from syncing context when we actually write/free space for this dnode */ 2169 void 2170 dnode_diduse_space(dnode_t *dn, int64_t delta) 2171 { 2172 uint64_t space; 2173 dprintf_dnode(dn, "dn=%p dnp=%p used=%llu delta=%lld\n", 2174 dn, dn->dn_phys, 2175 (u_longlong_t)dn->dn_phys->dn_used, 2176 (longlong_t)delta); 2177 2178 mutex_enter(&dn->dn_mtx); 2179 space = DN_USED_BYTES(dn->dn_phys); 2180 if (delta > 0) { 2181 ASSERT3U(space + delta, >=, space); /* no overflow */ 2182 } else { 2183 ASSERT3U(space, >=, -delta); /* no underflow */ 2184 } 2185 space += delta; 2186 if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_DNODE_BYTES) { 2187 ASSERT((dn->dn_phys->dn_flags & DNODE_FLAG_USED_BYTES) == 0); 2188 ASSERT0(P2PHASE(space, 1<<DEV_BSHIFT)); 2189 dn->dn_phys->dn_used = space >> DEV_BSHIFT; 2190 } else { 2191 dn->dn_phys->dn_used = space; 2192 dn->dn_phys->dn_flags |= DNODE_FLAG_USED_BYTES; 2193 } 2194 mutex_exit(&dn->dn_mtx); 2195 } 2196 2197 /* 2198 * Scans a block at the indicated "level" looking for a hole or data, 2199 * depending on 'flags'. 2200 * 2201 * If level > 0, then we are scanning an indirect block looking at its 2202 * pointers. If level == 0, then we are looking at a block of dnodes. 2203 * 2204 * If we don't find what we are looking for in the block, we return ESRCH. 2205 * Otherwise, return with *offset pointing to the beginning (if searching 2206 * forwards) or end (if searching backwards) of the range covered by the 2207 * block pointer we matched on (or dnode). 2208 * 2209 * The basic search algorithm used below by dnode_next_offset() is to 2210 * use this function to search up the block tree (widen the search) until 2211 * we find something (i.e., we don't return ESRCH) and then search back 2212 * down the tree (narrow the search) until we reach our original search 2213 * level. 2214 */ 2215 static int 2216 dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset, 2217 int lvl, uint64_t blkfill, uint64_t txg) 2218 { 2219 dmu_buf_impl_t *db = NULL; 2220 void *data = NULL; 2221 uint64_t epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2222 uint64_t epb = 1ULL << epbs; 2223 uint64_t minfill, maxfill; 2224 boolean_t hole; 2225 int i, inc, error, span; 2226 2227 dprintf("probing object %llu offset %llx level %d of %u\n", 2228 dn->dn_object, *offset, lvl, dn->dn_phys->dn_nlevels); 2229 2230 hole = ((flags & DNODE_FIND_HOLE) != 0); 2231 inc = (flags & DNODE_FIND_BACKWARDS) ? -1 : 1; 2232 ASSERT(txg == 0 || !hole); 2233 2234 if (lvl == dn->dn_phys->dn_nlevels) { 2235 error = 0; 2236 epb = dn->dn_phys->dn_nblkptr; 2237 data = dn->dn_phys->dn_blkptr; 2238 } else { 2239 uint64_t blkid = dbuf_whichblock(dn, lvl, *offset); 2240 error = dbuf_hold_impl(dn, lvl, blkid, TRUE, FALSE, FTAG, &db); 2241 if (error) { 2242 if (error != ENOENT) 2243 return (error); 2244 if (hole) 2245 return (0); 2246 /* 2247 * This can only happen when we are searching up 2248 * the block tree for data. We don't really need to 2249 * adjust the offset, as we will just end up looking 2250 * at the pointer to this block in its parent, and its 2251 * going to be unallocated, so we will skip over it. 2252 */ 2253 return (SET_ERROR(ESRCH)); 2254 } 2255 error = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_HAVESTRUCT); 2256 if (error) { 2257 dbuf_rele(db, FTAG); 2258 return (error); 2259 } 2260 data = db->db.db_data; 2261 } 2262 2263 2264 if (db != NULL && txg != 0 && (db->db_blkptr == NULL || 2265 db->db_blkptr->blk_birth <= txg || 2266 BP_IS_HOLE(db->db_blkptr))) { 2267 /* 2268 * This can only happen when we are searching up the tree 2269 * and these conditions mean that we need to keep climbing. 2270 */ 2271 error = SET_ERROR(ESRCH); 2272 } else if (lvl == 0) { 2273 dnode_phys_t *dnp = data; 2274 2275 ASSERT(dn->dn_type == DMU_OT_DNODE); 2276 ASSERT(!(flags & DNODE_FIND_BACKWARDS)); 2277 2278 for (i = (*offset >> DNODE_SHIFT) & (blkfill - 1); 2279 i < blkfill; i += dnp[i].dn_extra_slots + 1) { 2280 if ((dnp[i].dn_type == DMU_OT_NONE) == hole) 2281 break; 2282 } 2283 2284 if (i == blkfill) 2285 error = SET_ERROR(ESRCH); 2286 2287 *offset = (*offset & ~(DNODE_BLOCK_SIZE - 1)) + 2288 (i << DNODE_SHIFT); 2289 } else { 2290 blkptr_t *bp = data; 2291 uint64_t start = *offset; 2292 span = (lvl - 1) * epbs + dn->dn_datablkshift; 2293 minfill = 0; 2294 maxfill = blkfill << ((lvl - 1) * epbs); 2295 2296 if (hole) 2297 maxfill--; 2298 else 2299 minfill++; 2300 2301 *offset = *offset >> span; 2302 for (i = BF64_GET(*offset, 0, epbs); 2303 i >= 0 && i < epb; i += inc) { 2304 if (BP_GET_FILL(&bp[i]) >= minfill && 2305 BP_GET_FILL(&bp[i]) <= maxfill && 2306 (hole || bp[i].blk_birth > txg)) 2307 break; 2308 if (inc > 0 || *offset > 0) 2309 *offset += inc; 2310 } 2311 *offset = *offset << span; 2312 if (inc < 0) { 2313 /* traversing backwards; position offset at the end */ 2314 ASSERT3U(*offset, <=, start); 2315 *offset = MIN(*offset + (1ULL << span) - 1, start); 2316 } else if (*offset < start) { 2317 *offset = start; 2318 } 2319 if (i < 0 || i >= epb) 2320 error = SET_ERROR(ESRCH); 2321 } 2322 2323 if (db) 2324 dbuf_rele(db, FTAG); 2325 2326 return (error); 2327 } 2328 2329 /* 2330 * Find the next hole, data, or sparse region at or after *offset. 2331 * The value 'blkfill' tells us how many items we expect to find 2332 * in an L0 data block; this value is 1 for normal objects, 2333 * DNODES_PER_BLOCK for the meta dnode, and some fraction of 2334 * DNODES_PER_BLOCK when searching for sparse regions thereof. 2335 * 2336 * Examples: 2337 * 2338 * dnode_next_offset(dn, flags, offset, 1, 1, 0); 2339 * Finds the next/previous hole/data in a file. 2340 * Used in dmu_offset_next(). 2341 * 2342 * dnode_next_offset(mdn, flags, offset, 0, DNODES_PER_BLOCK, txg); 2343 * Finds the next free/allocated dnode an objset's meta-dnode. 2344 * Only finds objects that have new contents since txg (ie. 2345 * bonus buffer changes and content removal are ignored). 2346 * Used in dmu_object_next(). 2347 * 2348 * dnode_next_offset(mdn, DNODE_FIND_HOLE, offset, 2, DNODES_PER_BLOCK >> 2, 0); 2349 * Finds the next L2 meta-dnode bp that's at most 1/4 full. 2350 * Used in dmu_object_alloc(). 2351 */ 2352 int 2353 dnode_next_offset(dnode_t *dn, int flags, uint64_t *offset, 2354 int minlvl, uint64_t blkfill, uint64_t txg) 2355 { 2356 uint64_t initial_offset = *offset; 2357 int lvl, maxlvl; 2358 int error = 0; 2359 2360 if (!(flags & DNODE_FIND_HAVELOCK)) 2361 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2362 2363 if (dn->dn_phys->dn_nlevels == 0) { 2364 error = SET_ERROR(ESRCH); 2365 goto out; 2366 } 2367 2368 if (dn->dn_datablkshift == 0) { 2369 if (*offset < dn->dn_datablksz) { 2370 if (flags & DNODE_FIND_HOLE) 2371 *offset = dn->dn_datablksz; 2372 } else { 2373 error = SET_ERROR(ESRCH); 2374 } 2375 goto out; 2376 } 2377 2378 maxlvl = dn->dn_phys->dn_nlevels; 2379 2380 for (lvl = minlvl; lvl <= maxlvl; lvl++) { 2381 error = dnode_next_offset_level(dn, 2382 flags, offset, lvl, blkfill, txg); 2383 if (error != ESRCH) 2384 break; 2385 } 2386 2387 while (error == 0 && --lvl >= minlvl) { 2388 error = dnode_next_offset_level(dn, 2389 flags, offset, lvl, blkfill, txg); 2390 } 2391 2392 /* 2393 * There's always a "virtual hole" at the end of the object, even 2394 * if all BP's which physically exist are non-holes. 2395 */ 2396 if ((flags & DNODE_FIND_HOLE) && error == ESRCH && txg == 0 && 2397 minlvl == 1 && blkfill == 1 && !(flags & DNODE_FIND_BACKWARDS)) { 2398 error = 0; 2399 } 2400 2401 if (error == 0 && (flags & DNODE_FIND_BACKWARDS ? 2402 initial_offset < *offset : initial_offset > *offset)) 2403 error = SET_ERROR(ESRCH); 2404 out: 2405 if (!(flags & DNODE_FIND_HAVELOCK)) 2406 rw_exit(&dn->dn_struct_rwlock); 2407 2408 return (error); 2409 } 2410