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 zfs_refcount_create_untracked(&dn->dn_holds); 141 zfs_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 multilist_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_dirty_txg = 0; 164 dn->dn_dirtyctx = 0; 165 dn->dn_dirtyctx_firstset = NULL; 166 dn->dn_bonus = NULL; 167 dn->dn_have_spill = B_FALSE; 168 dn->dn_zio = NULL; 169 dn->dn_oldused = 0; 170 dn->dn_oldflags = 0; 171 dn->dn_olduid = 0; 172 dn->dn_oldgid = 0; 173 dn->dn_newuid = 0; 174 dn->dn_newgid = 0; 175 dn->dn_id_flags = 0; 176 177 dn->dn_dbufs_count = 0; 178 avl_create(&dn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t), 179 offsetof(dmu_buf_impl_t, db_link)); 180 181 dn->dn_moved = 0; 182 return (0); 183 } 184 185 /* ARGSUSED */ 186 static void 187 dnode_dest(void *arg, void *unused) 188 { 189 int i; 190 dnode_t *dn = arg; 191 192 rw_destroy(&dn->dn_struct_rwlock); 193 mutex_destroy(&dn->dn_mtx); 194 mutex_destroy(&dn->dn_dbufs_mtx); 195 cv_destroy(&dn->dn_notxholds); 196 zfs_refcount_destroy(&dn->dn_holds); 197 zfs_refcount_destroy(&dn->dn_tx_holds); 198 ASSERT(!list_link_active(&dn->dn_link)); 199 200 for (i = 0; i < TXG_SIZE; i++) { 201 ASSERT(!multilist_link_active(&dn->dn_dirty_link[i])); 202 ASSERT3P(dn->dn_free_ranges[i], ==, NULL); 203 list_destroy(&dn->dn_dirty_records[i]); 204 ASSERT0(dn->dn_next_nblkptr[i]); 205 ASSERT0(dn->dn_next_nlevels[i]); 206 ASSERT0(dn->dn_next_indblkshift[i]); 207 ASSERT0(dn->dn_next_bonustype[i]); 208 ASSERT0(dn->dn_rm_spillblk[i]); 209 ASSERT0(dn->dn_next_bonuslen[i]); 210 ASSERT0(dn->dn_next_blksz[i]); 211 } 212 213 ASSERT0(dn->dn_allocated_txg); 214 ASSERT0(dn->dn_free_txg); 215 ASSERT0(dn->dn_assigned_txg); 216 ASSERT0(dn->dn_dirty_txg); 217 ASSERT0(dn->dn_dirtyctx); 218 ASSERT3P(dn->dn_dirtyctx_firstset, ==, NULL); 219 ASSERT3P(dn->dn_bonus, ==, NULL); 220 ASSERT(!dn->dn_have_spill); 221 ASSERT3P(dn->dn_zio, ==, NULL); 222 ASSERT0(dn->dn_oldused); 223 ASSERT0(dn->dn_oldflags); 224 ASSERT0(dn->dn_olduid); 225 ASSERT0(dn->dn_oldgid); 226 ASSERT0(dn->dn_newuid); 227 ASSERT0(dn->dn_newgid); 228 ASSERT0(dn->dn_id_flags); 229 230 ASSERT0(dn->dn_dbufs_count); 231 avl_destroy(&dn->dn_dbufs); 232 } 233 234 void 235 dnode_init(void) 236 { 237 ASSERT(dnode_cache == NULL); 238 dnode_cache = kmem_cache_create("dnode_t", 239 sizeof (dnode_t), 240 0, dnode_cons, dnode_dest, NULL, NULL, NULL, 0); 241 #ifdef _KERNEL 242 kmem_cache_set_move(dnode_cache, dnode_move); 243 244 dnode_ksp = kstat_create("zfs", 0, "dnodestats", "misc", 245 KSTAT_TYPE_NAMED, sizeof (dnode_stats) / sizeof (kstat_named_t), 246 KSTAT_FLAG_VIRTUAL); 247 if (dnode_ksp != NULL) { 248 dnode_ksp->ks_data = &dnode_stats; 249 kstat_install(dnode_ksp); 250 } 251 #endif /* _KERNEL */ 252 } 253 254 void 255 dnode_fini(void) 256 { 257 if (dnode_ksp != NULL) { 258 kstat_delete(dnode_ksp); 259 dnode_ksp = NULL; 260 } 261 262 kmem_cache_destroy(dnode_cache); 263 dnode_cache = NULL; 264 } 265 266 267 #ifdef ZFS_DEBUG 268 void 269 dnode_verify(dnode_t *dn) 270 { 271 int drop_struct_lock = FALSE; 272 273 ASSERT(dn->dn_phys); 274 ASSERT(dn->dn_objset); 275 ASSERT(dn->dn_handle->dnh_dnode == dn); 276 277 ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type)); 278 279 if (!(zfs_flags & ZFS_DEBUG_DNODE_VERIFY)) 280 return; 281 282 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { 283 rw_enter(&dn->dn_struct_rwlock, RW_READER); 284 drop_struct_lock = TRUE; 285 } 286 if (dn->dn_phys->dn_type != DMU_OT_NONE || dn->dn_allocated_txg != 0) { 287 int i; 288 int max_bonuslen = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots); 289 ASSERT3U(dn->dn_indblkshift, >=, 0); 290 ASSERT3U(dn->dn_indblkshift, <=, SPA_MAXBLOCKSHIFT); 291 if (dn->dn_datablkshift) { 292 ASSERT3U(dn->dn_datablkshift, >=, SPA_MINBLOCKSHIFT); 293 ASSERT3U(dn->dn_datablkshift, <=, SPA_MAXBLOCKSHIFT); 294 ASSERT3U(1<<dn->dn_datablkshift, ==, dn->dn_datablksz); 295 } 296 ASSERT3U(dn->dn_nlevels, <=, 30); 297 ASSERT(DMU_OT_IS_VALID(dn->dn_type)); 298 ASSERT3U(dn->dn_nblkptr, >=, 1); 299 ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR); 300 ASSERT3U(dn->dn_bonuslen, <=, max_bonuslen); 301 ASSERT3U(dn->dn_datablksz, ==, 302 dn->dn_datablkszsec << SPA_MINBLOCKSHIFT); 303 ASSERT3U(ISP2(dn->dn_datablksz), ==, dn->dn_datablkshift != 0); 304 ASSERT3U((dn->dn_nblkptr - 1) * sizeof (blkptr_t) + 305 dn->dn_bonuslen, <=, max_bonuslen); 306 for (i = 0; i < TXG_SIZE; i++) { 307 ASSERT3U(dn->dn_next_nlevels[i], <=, dn->dn_nlevels); 308 } 309 } 310 if (dn->dn_phys->dn_type != DMU_OT_NONE) 311 ASSERT3U(dn->dn_phys->dn_nlevels, <=, dn->dn_nlevels); 312 ASSERT(DMU_OBJECT_IS_SPECIAL(dn->dn_object) || dn->dn_dbuf != NULL); 313 if (dn->dn_dbuf != NULL) { 314 ASSERT3P(dn->dn_phys, ==, 315 (dnode_phys_t *)dn->dn_dbuf->db.db_data + 316 (dn->dn_object % (dn->dn_dbuf->db.db_size >> DNODE_SHIFT))); 317 } 318 if (drop_struct_lock) 319 rw_exit(&dn->dn_struct_rwlock); 320 } 321 #endif 322 323 void 324 dnode_byteswap(dnode_phys_t *dnp) 325 { 326 uint64_t *buf64 = (void*)&dnp->dn_blkptr; 327 int i; 328 329 if (dnp->dn_type == DMU_OT_NONE) { 330 bzero(dnp, sizeof (dnode_phys_t)); 331 return; 332 } 333 334 dnp->dn_datablkszsec = BSWAP_16(dnp->dn_datablkszsec); 335 dnp->dn_bonuslen = BSWAP_16(dnp->dn_bonuslen); 336 dnp->dn_extra_slots = BSWAP_8(dnp->dn_extra_slots); 337 dnp->dn_maxblkid = BSWAP_64(dnp->dn_maxblkid); 338 dnp->dn_used = BSWAP_64(dnp->dn_used); 339 340 /* 341 * dn_nblkptr is only one byte, so it's OK to read it in either 342 * byte order. We can't read dn_bouslen. 343 */ 344 ASSERT(dnp->dn_indblkshift <= SPA_MAXBLOCKSHIFT); 345 ASSERT(dnp->dn_nblkptr <= DN_MAX_NBLKPTR); 346 for (i = 0; i < dnp->dn_nblkptr * sizeof (blkptr_t)/8; i++) 347 buf64[i] = BSWAP_64(buf64[i]); 348 349 /* 350 * OK to check dn_bonuslen for zero, because it won't matter if 351 * we have the wrong byte order. This is necessary because the 352 * dnode dnode is smaller than a regular dnode. 353 */ 354 if (dnp->dn_bonuslen != 0) { 355 /* 356 * Note that the bonus length calculated here may be 357 * longer than the actual bonus buffer. This is because 358 * we always put the bonus buffer after the last block 359 * pointer (instead of packing it against the end of the 360 * dnode buffer). 361 */ 362 int off = (dnp->dn_nblkptr-1) * sizeof (blkptr_t); 363 int slots = dnp->dn_extra_slots + 1; 364 size_t len = DN_SLOTS_TO_BONUSLEN(slots) - off; 365 ASSERT(DMU_OT_IS_VALID(dnp->dn_bonustype)); 366 dmu_object_byteswap_t byteswap = 367 DMU_OT_BYTESWAP(dnp->dn_bonustype); 368 dmu_ot_byteswap[byteswap].ob_func(dnp->dn_bonus + off, len); 369 } 370 371 /* Swap SPILL block if we have one */ 372 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) 373 byteswap_uint64_array(DN_SPILL_BLKPTR(dnp), sizeof (blkptr_t)); 374 375 } 376 377 void 378 dnode_buf_byteswap(void *vbuf, size_t size) 379 { 380 int i = 0; 381 382 ASSERT3U(sizeof (dnode_phys_t), ==, (1<<DNODE_SHIFT)); 383 ASSERT((size & (sizeof (dnode_phys_t)-1)) == 0); 384 385 while (i < size) { 386 dnode_phys_t *dnp = (void *)(((char *)vbuf) + i); 387 dnode_byteswap(dnp); 388 389 i += DNODE_MIN_SIZE; 390 if (dnp->dn_type != DMU_OT_NONE) 391 i += dnp->dn_extra_slots * DNODE_MIN_SIZE; 392 } 393 } 394 395 void 396 dnode_setbonuslen(dnode_t *dn, int newsize, dmu_tx_t *tx) 397 { 398 ASSERT3U(zfs_refcount_count(&dn->dn_holds), >=, 1); 399 400 dnode_setdirty(dn, tx); 401 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 402 ASSERT3U(newsize, <=, DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) - 403 (dn->dn_nblkptr-1) * sizeof (blkptr_t)); 404 dn->dn_bonuslen = newsize; 405 if (newsize == 0) 406 dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = DN_ZERO_BONUSLEN; 407 else 408 dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen; 409 rw_exit(&dn->dn_struct_rwlock); 410 } 411 412 void 413 dnode_setbonus_type(dnode_t *dn, dmu_object_type_t newtype, dmu_tx_t *tx) 414 { 415 ASSERT3U(zfs_refcount_count(&dn->dn_holds), >=, 1); 416 dnode_setdirty(dn, tx); 417 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 418 dn->dn_bonustype = newtype; 419 dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype; 420 rw_exit(&dn->dn_struct_rwlock); 421 } 422 423 void 424 dnode_rm_spill(dnode_t *dn, dmu_tx_t *tx) 425 { 426 ASSERT3U(zfs_refcount_count(&dn->dn_holds), >=, 1); 427 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 428 dnode_setdirty(dn, tx); 429 dn->dn_rm_spillblk[tx->tx_txg&TXG_MASK] = DN_KILL_SPILLBLK; 430 dn->dn_have_spill = B_FALSE; 431 } 432 433 static void 434 dnode_setdblksz(dnode_t *dn, int size) 435 { 436 ASSERT0(P2PHASE(size, SPA_MINBLOCKSIZE)); 437 ASSERT3U(size, <=, SPA_MAXBLOCKSIZE); 438 ASSERT3U(size, >=, SPA_MINBLOCKSIZE); 439 ASSERT3U(size >> SPA_MINBLOCKSHIFT, <, 440 1<<(sizeof (dn->dn_phys->dn_datablkszsec) * 8)); 441 dn->dn_datablksz = size; 442 dn->dn_datablkszsec = size >> SPA_MINBLOCKSHIFT; 443 dn->dn_datablkshift = ISP2(size) ? highbit64(size - 1) : 0; 444 } 445 446 static dnode_t * 447 dnode_create(objset_t *os, dnode_phys_t *dnp, dmu_buf_impl_t *db, 448 uint64_t object, dnode_handle_t *dnh) 449 { 450 dnode_t *dn; 451 452 dn = kmem_cache_alloc(dnode_cache, KM_SLEEP); 453 #ifdef _KERNEL 454 ASSERT(!POINTER_IS_VALID(dn->dn_objset)); 455 #endif /* _KERNEL */ 456 dn->dn_moved = 0; 457 458 /* 459 * Defer setting dn_objset until the dnode is ready to be a candidate 460 * for the dnode_move() callback. 461 */ 462 dn->dn_object = object; 463 dn->dn_dbuf = db; 464 dn->dn_handle = dnh; 465 dn->dn_phys = dnp; 466 467 if (dnp->dn_datablkszsec) { 468 dnode_setdblksz(dn, dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT); 469 } else { 470 dn->dn_datablksz = 0; 471 dn->dn_datablkszsec = 0; 472 dn->dn_datablkshift = 0; 473 } 474 dn->dn_indblkshift = dnp->dn_indblkshift; 475 dn->dn_nlevels = dnp->dn_nlevels; 476 dn->dn_type = dnp->dn_type; 477 dn->dn_nblkptr = dnp->dn_nblkptr; 478 dn->dn_checksum = dnp->dn_checksum; 479 dn->dn_compress = dnp->dn_compress; 480 dn->dn_bonustype = dnp->dn_bonustype; 481 dn->dn_bonuslen = dnp->dn_bonuslen; 482 dn->dn_num_slots = dnp->dn_extra_slots + 1; 483 dn->dn_maxblkid = dnp->dn_maxblkid; 484 dn->dn_have_spill = ((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0); 485 dn->dn_id_flags = 0; 486 487 dmu_zfetch_init(&dn->dn_zfetch, dn); 488 489 ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type)); 490 ASSERT(zrl_is_locked(&dnh->dnh_zrlock)); 491 ASSERT(!DN_SLOT_IS_PTR(dnh->dnh_dnode)); 492 493 mutex_enter(&os->os_lock); 494 495 /* 496 * Exclude special dnodes from os_dnodes so an empty os_dnodes 497 * signifies that the special dnodes have no references from 498 * their children (the entries in os_dnodes). This allows 499 * dnode_destroy() to easily determine if the last child has 500 * been removed and then complete eviction of the objset. 501 */ 502 if (!DMU_OBJECT_IS_SPECIAL(object)) 503 list_insert_head(&os->os_dnodes, dn); 504 membar_producer(); 505 506 /* 507 * Everything else must be valid before assigning dn_objset 508 * makes the dnode eligible for dnode_move(). 509 */ 510 dn->dn_objset = os; 511 512 dnh->dnh_dnode = dn; 513 mutex_exit(&os->os_lock); 514 515 arc_space_consume(sizeof (dnode_t), ARC_SPACE_OTHER); 516 517 return (dn); 518 } 519 520 /* 521 * Caller must be holding the dnode handle, which is released upon return. 522 */ 523 static void 524 dnode_destroy(dnode_t *dn) 525 { 526 objset_t *os = dn->dn_objset; 527 boolean_t complete_os_eviction = B_FALSE; 528 529 ASSERT((dn->dn_id_flags & DN_ID_NEW_EXIST) == 0); 530 531 mutex_enter(&os->os_lock); 532 POINTER_INVALIDATE(&dn->dn_objset); 533 if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) { 534 list_remove(&os->os_dnodes, dn); 535 complete_os_eviction = 536 list_is_empty(&os->os_dnodes) && 537 list_link_active(&os->os_evicting_node); 538 } 539 mutex_exit(&os->os_lock); 540 541 /* the dnode can no longer move, so we can release the handle */ 542 if (!zrl_is_locked(&dn->dn_handle->dnh_zrlock)) 543 zrl_remove(&dn->dn_handle->dnh_zrlock); 544 545 dn->dn_allocated_txg = 0; 546 dn->dn_free_txg = 0; 547 dn->dn_assigned_txg = 0; 548 dn->dn_dirty_txg = 0; 549 550 dn->dn_dirtyctx = 0; 551 if (dn->dn_dirtyctx_firstset != NULL) { 552 kmem_free(dn->dn_dirtyctx_firstset, 1); 553 dn->dn_dirtyctx_firstset = NULL; 554 } 555 if (dn->dn_bonus != NULL) { 556 mutex_enter(&dn->dn_bonus->db_mtx); 557 dbuf_destroy(dn->dn_bonus); 558 dn->dn_bonus = NULL; 559 } 560 dn->dn_zio = NULL; 561 562 dn->dn_have_spill = B_FALSE; 563 dn->dn_oldused = 0; 564 dn->dn_oldflags = 0; 565 dn->dn_olduid = 0; 566 dn->dn_oldgid = 0; 567 dn->dn_newuid = 0; 568 dn->dn_newgid = 0; 569 dn->dn_id_flags = 0; 570 571 dmu_zfetch_fini(&dn->dn_zfetch); 572 kmem_cache_free(dnode_cache, dn); 573 arc_space_return(sizeof (dnode_t), ARC_SPACE_OTHER); 574 575 if (complete_os_eviction) 576 dmu_objset_evict_done(os); 577 } 578 579 void 580 dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs, 581 dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx) 582 { 583 int i; 584 585 ASSERT3U(dn_slots, >, 0); 586 ASSERT3U(dn_slots << DNODE_SHIFT, <=, 587 spa_maxdnodesize(dmu_objset_spa(dn->dn_objset))); 588 ASSERT3U(blocksize, <=, 589 spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); 590 if (blocksize == 0) 591 blocksize = 1 << zfs_default_bs; 592 else 593 blocksize = P2ROUNDUP(blocksize, SPA_MINBLOCKSIZE); 594 595 if (ibs == 0) 596 ibs = zfs_default_ibs; 597 598 ibs = MIN(MAX(ibs, DN_MIN_INDBLKSHIFT), DN_MAX_INDBLKSHIFT); 599 600 dprintf("os=%p obj=%" PRIu64 " txg=%" PRIu64 601 " blocksize=%d ibs=%d dn_slots=%d\n", 602 dn->dn_objset, dn->dn_object, tx->tx_txg, blocksize, ibs, dn_slots); 603 DNODE_STAT_BUMP(dnode_allocate); 604 605 ASSERT(dn->dn_type == DMU_OT_NONE); 606 ASSERT(bcmp(dn->dn_phys, &dnode_phys_zero, sizeof (dnode_phys_t)) == 0); 607 ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE); 608 ASSERT(ot != DMU_OT_NONE); 609 ASSERT(DMU_OT_IS_VALID(ot)); 610 ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) || 611 (bonustype == DMU_OT_SA && bonuslen == 0) || 612 (bonustype != DMU_OT_NONE && bonuslen != 0)); 613 ASSERT(DMU_OT_IS_VALID(bonustype)); 614 ASSERT3U(bonuslen, <=, DN_SLOTS_TO_BONUSLEN(dn_slots)); 615 ASSERT(dn->dn_type == DMU_OT_NONE); 616 ASSERT0(dn->dn_maxblkid); 617 ASSERT0(dn->dn_allocated_txg); 618 ASSERT0(dn->dn_dirty_txg); 619 ASSERT0(dn->dn_assigned_txg); 620 ASSERT(zfs_refcount_is_zero(&dn->dn_tx_holds)); 621 ASSERT3U(zfs_refcount_count(&dn->dn_holds), <=, 1); 622 ASSERT(avl_is_empty(&dn->dn_dbufs)); 623 624 for (i = 0; i < TXG_SIZE; i++) { 625 ASSERT0(dn->dn_next_nblkptr[i]); 626 ASSERT0(dn->dn_next_nlevels[i]); 627 ASSERT0(dn->dn_next_indblkshift[i]); 628 ASSERT0(dn->dn_next_bonuslen[i]); 629 ASSERT0(dn->dn_next_bonustype[i]); 630 ASSERT0(dn->dn_rm_spillblk[i]); 631 ASSERT0(dn->dn_next_blksz[i]); 632 ASSERT(!multilist_link_active(&dn->dn_dirty_link[i])); 633 ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL); 634 ASSERT3P(dn->dn_free_ranges[i], ==, NULL); 635 } 636 637 dn->dn_type = ot; 638 dnode_setdblksz(dn, blocksize); 639 dn->dn_indblkshift = ibs; 640 dn->dn_nlevels = 1; 641 dn->dn_num_slots = dn_slots; 642 if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */ 643 dn->dn_nblkptr = 1; 644 else { 645 dn->dn_nblkptr = MIN(DN_MAX_NBLKPTR, 646 1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >> 647 SPA_BLKPTRSHIFT)); 648 } 649 650 dn->dn_bonustype = bonustype; 651 dn->dn_bonuslen = bonuslen; 652 dn->dn_checksum = ZIO_CHECKSUM_INHERIT; 653 dn->dn_compress = ZIO_COMPRESS_INHERIT; 654 dn->dn_dirtyctx = 0; 655 656 dn->dn_free_txg = 0; 657 if (dn->dn_dirtyctx_firstset) { 658 kmem_free(dn->dn_dirtyctx_firstset, 1); 659 dn->dn_dirtyctx_firstset = NULL; 660 } 661 662 dn->dn_allocated_txg = tx->tx_txg; 663 dn->dn_id_flags = 0; 664 665 dnode_setdirty(dn, tx); 666 dn->dn_next_indblkshift[tx->tx_txg & TXG_MASK] = ibs; 667 dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen; 668 dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype; 669 dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = dn->dn_datablksz; 670 } 671 672 void 673 dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, 674 dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx) 675 { 676 int nblkptr; 677 678 ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE); 679 ASSERT3U(blocksize, <=, 680 spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); 681 ASSERT0(blocksize % SPA_MINBLOCKSIZE); 682 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT || dmu_tx_private_ok(tx)); 683 ASSERT(tx->tx_txg != 0); 684 ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) || 685 (bonustype != DMU_OT_NONE && bonuslen != 0) || 686 (bonustype == DMU_OT_SA && bonuslen == 0)); 687 ASSERT(DMU_OT_IS_VALID(bonustype)); 688 ASSERT3U(bonuslen, <=, 689 DN_BONUS_SIZE(spa_maxdnodesize(dmu_objset_spa(dn->dn_objset)))); 690 ASSERT3U(bonuslen, <=, DN_BONUS_SIZE(dn_slots << DNODE_SHIFT)); 691 692 dnode_free_interior_slots(dn); 693 DNODE_STAT_BUMP(dnode_reallocate); 694 695 /* clean up any unreferenced dbufs */ 696 dnode_evict_dbufs(dn); 697 698 dn->dn_id_flags = 0; 699 700 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 701 dnode_setdirty(dn, tx); 702 if (dn->dn_datablksz != blocksize) { 703 /* change blocksize */ 704 ASSERT(dn->dn_maxblkid == 0 && 705 (BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) || 706 dnode_block_freed(dn, 0))); 707 dnode_setdblksz(dn, blocksize); 708 dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize; 709 } 710 if (dn->dn_bonuslen != bonuslen) 711 dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen; 712 713 if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */ 714 nblkptr = 1; 715 else 716 nblkptr = MIN(DN_MAX_NBLKPTR, 717 1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >> 718 SPA_BLKPTRSHIFT)); 719 if (dn->dn_bonustype != bonustype) 720 dn->dn_next_bonustype[tx->tx_txg&TXG_MASK] = bonustype; 721 if (dn->dn_nblkptr != nblkptr) 722 dn->dn_next_nblkptr[tx->tx_txg&TXG_MASK] = nblkptr; 723 if (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR) { 724 dbuf_rm_spill(dn, tx); 725 dnode_rm_spill(dn, tx); 726 } 727 rw_exit(&dn->dn_struct_rwlock); 728 729 /* change type */ 730 dn->dn_type = ot; 731 732 /* change bonus size and type */ 733 mutex_enter(&dn->dn_mtx); 734 dn->dn_bonustype = bonustype; 735 dn->dn_bonuslen = bonuslen; 736 dn->dn_num_slots = dn_slots; 737 dn->dn_nblkptr = nblkptr; 738 dn->dn_checksum = ZIO_CHECKSUM_INHERIT; 739 dn->dn_compress = ZIO_COMPRESS_INHERIT; 740 ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR); 741 742 /* fix up the bonus db_size */ 743 if (dn->dn_bonus) { 744 dn->dn_bonus->db.db_size = 745 DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) - 746 (dn->dn_nblkptr - 1) * sizeof (blkptr_t); 747 ASSERT(dn->dn_bonuslen <= dn->dn_bonus->db.db_size); 748 } 749 750 dn->dn_allocated_txg = tx->tx_txg; 751 mutex_exit(&dn->dn_mtx); 752 } 753 754 #ifdef _KERNEL 755 static void 756 dnode_move_impl(dnode_t *odn, dnode_t *ndn) 757 { 758 int i; 759 760 ASSERT(!RW_LOCK_HELD(&odn->dn_struct_rwlock)); 761 ASSERT(MUTEX_NOT_HELD(&odn->dn_mtx)); 762 ASSERT(MUTEX_NOT_HELD(&odn->dn_dbufs_mtx)); 763 ASSERT(!RW_LOCK_HELD(&odn->dn_zfetch.zf_rwlock)); 764 765 /* Copy fields. */ 766 ndn->dn_objset = odn->dn_objset; 767 ndn->dn_object = odn->dn_object; 768 ndn->dn_dbuf = odn->dn_dbuf; 769 ndn->dn_handle = odn->dn_handle; 770 ndn->dn_phys = odn->dn_phys; 771 ndn->dn_type = odn->dn_type; 772 ndn->dn_bonuslen = odn->dn_bonuslen; 773 ndn->dn_bonustype = odn->dn_bonustype; 774 ndn->dn_nblkptr = odn->dn_nblkptr; 775 ndn->dn_checksum = odn->dn_checksum; 776 ndn->dn_compress = odn->dn_compress; 777 ndn->dn_nlevels = odn->dn_nlevels; 778 ndn->dn_indblkshift = odn->dn_indblkshift; 779 ndn->dn_datablkshift = odn->dn_datablkshift; 780 ndn->dn_datablkszsec = odn->dn_datablkszsec; 781 ndn->dn_datablksz = odn->dn_datablksz; 782 ndn->dn_maxblkid = odn->dn_maxblkid; 783 ndn->dn_num_slots = odn->dn_num_slots; 784 bcopy(&odn->dn_next_type[0], &ndn->dn_next_type[0], 785 sizeof (odn->dn_next_type)); 786 bcopy(&odn->dn_next_nblkptr[0], &ndn->dn_next_nblkptr[0], 787 sizeof (odn->dn_next_nblkptr)); 788 bcopy(&odn->dn_next_nlevels[0], &ndn->dn_next_nlevels[0], 789 sizeof (odn->dn_next_nlevels)); 790 bcopy(&odn->dn_next_indblkshift[0], &ndn->dn_next_indblkshift[0], 791 sizeof (odn->dn_next_indblkshift)); 792 bcopy(&odn->dn_next_bonustype[0], &ndn->dn_next_bonustype[0], 793 sizeof (odn->dn_next_bonustype)); 794 bcopy(&odn->dn_rm_spillblk[0], &ndn->dn_rm_spillblk[0], 795 sizeof (odn->dn_rm_spillblk)); 796 bcopy(&odn->dn_next_bonuslen[0], &ndn->dn_next_bonuslen[0], 797 sizeof (odn->dn_next_bonuslen)); 798 bcopy(&odn->dn_next_blksz[0], &ndn->dn_next_blksz[0], 799 sizeof (odn->dn_next_blksz)); 800 for (i = 0; i < TXG_SIZE; i++) { 801 list_move_tail(&ndn->dn_dirty_records[i], 802 &odn->dn_dirty_records[i]); 803 } 804 bcopy(&odn->dn_free_ranges[0], &ndn->dn_free_ranges[0], 805 sizeof (odn->dn_free_ranges)); 806 ndn->dn_allocated_txg = odn->dn_allocated_txg; 807 ndn->dn_free_txg = odn->dn_free_txg; 808 ndn->dn_assigned_txg = odn->dn_assigned_txg; 809 ndn->dn_dirty_txg = odn->dn_dirty_txg; 810 ndn->dn_dirtyctx = odn->dn_dirtyctx; 811 ndn->dn_dirtyctx_firstset = odn->dn_dirtyctx_firstset; 812 ASSERT(zfs_refcount_count(&odn->dn_tx_holds) == 0); 813 zfs_refcount_transfer(&ndn->dn_holds, &odn->dn_holds); 814 ASSERT(avl_is_empty(&ndn->dn_dbufs)); 815 avl_swap(&ndn->dn_dbufs, &odn->dn_dbufs); 816 ndn->dn_dbufs_count = odn->dn_dbufs_count; 817 ndn->dn_bonus = odn->dn_bonus; 818 ndn->dn_have_spill = odn->dn_have_spill; 819 ndn->dn_zio = odn->dn_zio; 820 ndn->dn_oldused = odn->dn_oldused; 821 ndn->dn_oldflags = odn->dn_oldflags; 822 ndn->dn_olduid = odn->dn_olduid; 823 ndn->dn_oldgid = odn->dn_oldgid; 824 ndn->dn_newuid = odn->dn_newuid; 825 ndn->dn_newgid = odn->dn_newgid; 826 ndn->dn_id_flags = odn->dn_id_flags; 827 dmu_zfetch_init(&ndn->dn_zfetch, NULL); 828 list_move_tail(&ndn->dn_zfetch.zf_stream, &odn->dn_zfetch.zf_stream); 829 ndn->dn_zfetch.zf_dnode = odn->dn_zfetch.zf_dnode; 830 831 /* 832 * Update back pointers. Updating the handle fixes the back pointer of 833 * every descendant dbuf as well as the bonus dbuf. 834 */ 835 ASSERT(ndn->dn_handle->dnh_dnode == odn); 836 ndn->dn_handle->dnh_dnode = ndn; 837 if (ndn->dn_zfetch.zf_dnode == odn) { 838 ndn->dn_zfetch.zf_dnode = ndn; 839 } 840 841 /* 842 * Invalidate the original dnode by clearing all of its back pointers. 843 */ 844 odn->dn_dbuf = NULL; 845 odn->dn_handle = NULL; 846 avl_create(&odn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t), 847 offsetof(dmu_buf_impl_t, db_link)); 848 odn->dn_dbufs_count = 0; 849 odn->dn_bonus = NULL; 850 odn->dn_zfetch.zf_dnode = NULL; 851 852 /* 853 * Set the low bit of the objset pointer to ensure that dnode_move() 854 * recognizes the dnode as invalid in any subsequent callback. 855 */ 856 POINTER_INVALIDATE(&odn->dn_objset); 857 858 /* 859 * Satisfy the destructor. 860 */ 861 for (i = 0; i < TXG_SIZE; i++) { 862 list_create(&odn->dn_dirty_records[i], 863 sizeof (dbuf_dirty_record_t), 864 offsetof(dbuf_dirty_record_t, dr_dirty_node)); 865 odn->dn_free_ranges[i] = NULL; 866 odn->dn_next_nlevels[i] = 0; 867 odn->dn_next_indblkshift[i] = 0; 868 odn->dn_next_bonustype[i] = 0; 869 odn->dn_rm_spillblk[i] = 0; 870 odn->dn_next_bonuslen[i] = 0; 871 odn->dn_next_blksz[i] = 0; 872 } 873 odn->dn_allocated_txg = 0; 874 odn->dn_free_txg = 0; 875 odn->dn_assigned_txg = 0; 876 odn->dn_dirty_txg = 0; 877 odn->dn_dirtyctx = 0; 878 odn->dn_dirtyctx_firstset = NULL; 879 odn->dn_have_spill = B_FALSE; 880 odn->dn_zio = NULL; 881 odn->dn_oldused = 0; 882 odn->dn_oldflags = 0; 883 odn->dn_olduid = 0; 884 odn->dn_oldgid = 0; 885 odn->dn_newuid = 0; 886 odn->dn_newgid = 0; 887 odn->dn_id_flags = 0; 888 889 /* 890 * Mark the dnode. 891 */ 892 ndn->dn_moved = 1; 893 odn->dn_moved = (uint8_t)-1; 894 } 895 896 /*ARGSUSED*/ 897 static kmem_cbrc_t 898 dnode_move(void *buf, void *newbuf, size_t size, void *arg) 899 { 900 dnode_t *odn = buf, *ndn = newbuf; 901 objset_t *os; 902 int64_t refcount; 903 uint32_t dbufs; 904 905 /* 906 * The dnode is on the objset's list of known dnodes if the objset 907 * pointer is valid. We set the low bit of the objset pointer when 908 * freeing the dnode to invalidate it, and the memory patterns written 909 * by kmem (baddcafe and deadbeef) set at least one of the two low bits. 910 * A newly created dnode sets the objset pointer last of all to indicate 911 * that the dnode is known and in a valid state to be moved by this 912 * function. 913 */ 914 os = odn->dn_objset; 915 if (!POINTER_IS_VALID(os)) { 916 DNODE_STAT_BUMP(dnode_move_invalid); 917 return (KMEM_CBRC_DONT_KNOW); 918 } 919 920 /* 921 * Ensure that the objset does not go away during the move. 922 */ 923 rw_enter(&os_lock, RW_WRITER); 924 if (os != odn->dn_objset) { 925 rw_exit(&os_lock); 926 DNODE_STAT_BUMP(dnode_move_recheck1); 927 return (KMEM_CBRC_DONT_KNOW); 928 } 929 930 /* 931 * If the dnode is still valid, then so is the objset. We know that no 932 * valid objset can be freed while we hold os_lock, so we can safely 933 * ensure that the objset remains in use. 934 */ 935 mutex_enter(&os->os_lock); 936 937 /* 938 * Recheck the objset pointer in case the dnode was removed just before 939 * acquiring the lock. 940 */ 941 if (os != odn->dn_objset) { 942 mutex_exit(&os->os_lock); 943 rw_exit(&os_lock); 944 DNODE_STAT_BUMP(dnode_move_recheck2); 945 return (KMEM_CBRC_DONT_KNOW); 946 } 947 948 /* 949 * At this point we know that as long as we hold os->os_lock, the dnode 950 * cannot be freed and fields within the dnode can be safely accessed. 951 * The objset listing this dnode cannot go away as long as this dnode is 952 * on its list. 953 */ 954 rw_exit(&os_lock); 955 if (DMU_OBJECT_IS_SPECIAL(odn->dn_object)) { 956 mutex_exit(&os->os_lock); 957 DNODE_STAT_BUMP(dnode_move_special); 958 return (KMEM_CBRC_NO); 959 } 960 ASSERT(odn->dn_dbuf != NULL); /* only "special" dnodes have no parent */ 961 962 /* 963 * Lock the dnode handle to prevent the dnode from obtaining any new 964 * holds. This also prevents the descendant dbufs and the bonus dbuf 965 * from accessing the dnode, so that we can discount their holds. The 966 * handle is safe to access because we know that while the dnode cannot 967 * go away, neither can its handle. Once we hold dnh_zrlock, we can 968 * safely move any dnode referenced only by dbufs. 969 */ 970 if (!zrl_tryenter(&odn->dn_handle->dnh_zrlock)) { 971 mutex_exit(&os->os_lock); 972 DNODE_STAT_BUMP(dnode_move_handle); 973 return (KMEM_CBRC_LATER); 974 } 975 976 /* 977 * Ensure a consistent view of the dnode's holds and the dnode's dbufs. 978 * We need to guarantee that there is a hold for every dbuf in order to 979 * determine whether the dnode is actively referenced. Falsely matching 980 * a dbuf to an active hold would lead to an unsafe move. It's possible 981 * that a thread already having an active dnode hold is about to add a 982 * dbuf, and we can't compare hold and dbuf counts while the add is in 983 * progress. 984 */ 985 if (!rw_tryenter(&odn->dn_struct_rwlock, RW_WRITER)) { 986 zrl_exit(&odn->dn_handle->dnh_zrlock); 987 mutex_exit(&os->os_lock); 988 DNODE_STAT_BUMP(dnode_move_rwlock); 989 return (KMEM_CBRC_LATER); 990 } 991 992 /* 993 * A dbuf may be removed (evicted) without an active dnode hold. In that 994 * case, the dbuf count is decremented under the handle lock before the 995 * dbuf's hold is released. This order ensures that if we count the hold 996 * after the dbuf is removed but before its hold is released, we will 997 * treat the unmatched hold as active and exit safely. If we count the 998 * hold before the dbuf is removed, the hold is discounted, and the 999 * removal is blocked until the move completes. 1000 */ 1001 refcount = zfs_refcount_count(&odn->dn_holds); 1002 ASSERT(refcount >= 0); 1003 dbufs = odn->dn_dbufs_count; 1004 1005 /* We can't have more dbufs than dnode holds. */ 1006 ASSERT3U(dbufs, <=, refcount); 1007 DTRACE_PROBE3(dnode__move, dnode_t *, odn, int64_t, refcount, 1008 uint32_t, dbufs); 1009 1010 if (refcount > dbufs) { 1011 rw_exit(&odn->dn_struct_rwlock); 1012 zrl_exit(&odn->dn_handle->dnh_zrlock); 1013 mutex_exit(&os->os_lock); 1014 DNODE_STAT_BUMP(dnode_move_active); 1015 return (KMEM_CBRC_LATER); 1016 } 1017 1018 rw_exit(&odn->dn_struct_rwlock); 1019 1020 /* 1021 * At this point we know that anyone with a hold on the dnode is not 1022 * actively referencing it. The dnode is known and in a valid state to 1023 * move. We're holding the locks needed to execute the critical section. 1024 */ 1025 dnode_move_impl(odn, ndn); 1026 1027 list_link_replace(&odn->dn_link, &ndn->dn_link); 1028 /* If the dnode was safe to move, the refcount cannot have changed. */ 1029 ASSERT(refcount == zfs_refcount_count(&ndn->dn_holds)); 1030 ASSERT(dbufs == ndn->dn_dbufs_count); 1031 zrl_exit(&ndn->dn_handle->dnh_zrlock); /* handle has moved */ 1032 mutex_exit(&os->os_lock); 1033 1034 return (KMEM_CBRC_YES); 1035 } 1036 #endif /* _KERNEL */ 1037 1038 static void 1039 dnode_slots_hold(dnode_children_t *children, int idx, int slots) 1040 { 1041 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1042 1043 for (int i = idx; i < idx + slots; i++) { 1044 dnode_handle_t *dnh = &children->dnc_children[i]; 1045 zrl_add(&dnh->dnh_zrlock); 1046 } 1047 } 1048 1049 static void 1050 dnode_slots_rele(dnode_children_t *children, int idx, int slots) 1051 { 1052 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1053 1054 for (int i = idx; i < idx + slots; i++) { 1055 dnode_handle_t *dnh = &children->dnc_children[i]; 1056 1057 if (zrl_is_locked(&dnh->dnh_zrlock)) 1058 zrl_exit(&dnh->dnh_zrlock); 1059 else 1060 zrl_remove(&dnh->dnh_zrlock); 1061 } 1062 } 1063 1064 static int 1065 dnode_slots_tryenter(dnode_children_t *children, int idx, int slots) 1066 { 1067 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1068 1069 for (int i = idx; i < idx + slots; i++) { 1070 dnode_handle_t *dnh = &children->dnc_children[i]; 1071 1072 if (!zrl_tryenter(&dnh->dnh_zrlock)) { 1073 for (int j = idx; j < i; j++) { 1074 dnh = &children->dnc_children[j]; 1075 zrl_exit(&dnh->dnh_zrlock); 1076 } 1077 1078 return (0); 1079 } 1080 } 1081 1082 return (1); 1083 } 1084 1085 static void 1086 dnode_set_slots(dnode_children_t *children, int idx, int slots, void *ptr) 1087 { 1088 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1089 1090 for (int i = idx; i < idx + slots; i++) { 1091 dnode_handle_t *dnh = &children->dnc_children[i]; 1092 dnh->dnh_dnode = ptr; 1093 } 1094 } 1095 1096 static boolean_t 1097 dnode_check_slots_free(dnode_children_t *children, int idx, int slots) 1098 { 1099 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1100 1101 /* 1102 * If all dnode slots are either already free or 1103 * evictable return B_TRUE. 1104 */ 1105 for (int i = idx; i < idx + slots; i++) { 1106 dnode_handle_t *dnh = &children->dnc_children[i]; 1107 dnode_t *dn = dnh->dnh_dnode; 1108 1109 if (dn == DN_SLOT_FREE) { 1110 continue; 1111 } else if (DN_SLOT_IS_PTR(dn)) { 1112 mutex_enter(&dn->dn_mtx); 1113 boolean_t can_free = (dn->dn_type == DMU_OT_NONE && 1114 zfs_refcount_is_zero(&dn->dn_holds) && 1115 !DNODE_IS_DIRTY(dn)); 1116 mutex_exit(&dn->dn_mtx); 1117 1118 if (!can_free) 1119 return (B_FALSE); 1120 else 1121 continue; 1122 } else { 1123 return (B_FALSE); 1124 } 1125 } 1126 1127 return (B_TRUE); 1128 } 1129 1130 static void 1131 dnode_reclaim_slots(dnode_children_t *children, int idx, int slots) 1132 { 1133 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1134 1135 for (int i = idx; i < idx + slots; i++) { 1136 dnode_handle_t *dnh = &children->dnc_children[i]; 1137 1138 ASSERT(zrl_is_locked(&dnh->dnh_zrlock)); 1139 1140 if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { 1141 ASSERT3S(dnh->dnh_dnode->dn_type, ==, DMU_OT_NONE); 1142 dnode_destroy(dnh->dnh_dnode); 1143 dnh->dnh_dnode = DN_SLOT_FREE; 1144 } 1145 } 1146 } 1147 1148 void 1149 dnode_free_interior_slots(dnode_t *dn) 1150 { 1151 dnode_children_t *children = dmu_buf_get_user(&dn->dn_dbuf->db); 1152 int epb = dn->dn_dbuf->db.db_size >> DNODE_SHIFT; 1153 int idx = (dn->dn_object & (epb - 1)) + 1; 1154 int slots = dn->dn_num_slots - 1; 1155 1156 if (slots == 0) 1157 return; 1158 1159 ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); 1160 1161 while (!dnode_slots_tryenter(children, idx, slots)) 1162 DNODE_STAT_BUMP(dnode_free_interior_lock_retry); 1163 1164 dnode_set_slots(children, idx, slots, DN_SLOT_FREE); 1165 dnode_slots_rele(children, idx, slots); 1166 } 1167 1168 void 1169 dnode_special_close(dnode_handle_t *dnh) 1170 { 1171 dnode_t *dn = dnh->dnh_dnode; 1172 1173 /* 1174 * Wait for final references to the dnode to clear. This can 1175 * only happen if the arc is asynchronously evicting state that 1176 * has a hold on this dnode while we are trying to evict this 1177 * dnode. 1178 */ 1179 while (zfs_refcount_count(&dn->dn_holds) > 0) 1180 delay(1); 1181 ASSERT(dn->dn_dbuf == NULL || 1182 dmu_buf_get_user(&dn->dn_dbuf->db) == NULL); 1183 zrl_add(&dnh->dnh_zrlock); 1184 dnode_destroy(dn); /* implicit zrl_remove() */ 1185 zrl_destroy(&dnh->dnh_zrlock); 1186 dnh->dnh_dnode = NULL; 1187 } 1188 1189 void 1190 dnode_special_open(objset_t *os, dnode_phys_t *dnp, uint64_t object, 1191 dnode_handle_t *dnh) 1192 { 1193 dnode_t *dn; 1194 1195 zrl_init(&dnh->dnh_zrlock); 1196 zrl_tryenter(&dnh->dnh_zrlock); 1197 1198 dn = dnode_create(os, dnp, NULL, object, dnh); 1199 DNODE_VERIFY(dn); 1200 1201 zrl_exit(&dnh->dnh_zrlock); 1202 } 1203 1204 static void 1205 dnode_buf_evict_async(void *dbu) 1206 { 1207 dnode_children_t *dnc = dbu; 1208 1209 DNODE_STAT_BUMP(dnode_buf_evict); 1210 1211 for (int i = 0; i < dnc->dnc_count; i++) { 1212 dnode_handle_t *dnh = &dnc->dnc_children[i]; 1213 dnode_t *dn; 1214 1215 /* 1216 * The dnode handle lock guards against the dnode moving to 1217 * another valid address, so there is no need here to guard 1218 * against changes to or from NULL. 1219 */ 1220 if (!DN_SLOT_IS_PTR(dnh->dnh_dnode)) { 1221 zrl_destroy(&dnh->dnh_zrlock); 1222 dnh->dnh_dnode = DN_SLOT_UNINIT; 1223 continue; 1224 } 1225 1226 zrl_add(&dnh->dnh_zrlock); 1227 dn = dnh->dnh_dnode; 1228 /* 1229 * If there are holds on this dnode, then there should 1230 * be holds on the dnode's containing dbuf as well; thus 1231 * it wouldn't be eligible for eviction and this function 1232 * would not have been called. 1233 */ 1234 ASSERT(zfs_refcount_is_zero(&dn->dn_holds)); 1235 ASSERT(zfs_refcount_is_zero(&dn->dn_tx_holds)); 1236 1237 dnode_destroy(dn); /* implicit zrl_remove() for first slot */ 1238 zrl_destroy(&dnh->dnh_zrlock); 1239 dnh->dnh_dnode = DN_SLOT_UNINIT; 1240 } 1241 kmem_free(dnc, sizeof (dnode_children_t) + 1242 dnc->dnc_count * sizeof (dnode_handle_t)); 1243 } 1244 1245 /* 1246 * When the DNODE_MUST_BE_FREE flag is set, the "slots" parameter is used 1247 * to ensure the hole at the specified object offset is large enough to 1248 * hold the dnode being created. The slots parameter is also used to ensure 1249 * a dnode does not span multiple dnode blocks. In both of these cases, if 1250 * a failure occurs, ENOSPC is returned. Keep in mind, these failure cases 1251 * are only possible when using DNODE_MUST_BE_FREE. 1252 * 1253 * If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. 1254 * dnode_hold_impl() will check if the requested dnode is already consumed 1255 * as an extra dnode slot by an large dnode, in which case it returns 1256 * ENOENT. 1257 * 1258 * errors: 1259 * EINVAL - invalid object number or flags. 1260 * ENOSPC - hole too small to fulfill "slots" request (DNODE_MUST_BE_FREE) 1261 * EEXIST - Refers to an allocated dnode (DNODE_MUST_BE_FREE) 1262 * - Refers to a freeing dnode (DNODE_MUST_BE_FREE) 1263 * - Refers to an interior dnode slot (DNODE_MUST_BE_ALLOCATED) 1264 * ENOENT - The requested dnode is not allocated (DNODE_MUST_BE_ALLOCATED) 1265 * - The requested dnode is being freed (DNODE_MUST_BE_ALLOCATED) 1266 * EIO - i/o error error when reading the meta dnode dbuf. 1267 * succeeds even for free dnodes. 1268 */ 1269 int 1270 dnode_hold_impl(objset_t *os, uint64_t object, int flag, int slots, 1271 void *tag, dnode_t **dnp) 1272 { 1273 int epb, idx, err; 1274 int drop_struct_lock = FALSE; 1275 int type; 1276 uint64_t blk; 1277 dnode_t *mdn, *dn; 1278 dmu_buf_impl_t *db; 1279 dnode_children_t *dnc; 1280 dnode_phys_t *dn_block; 1281 dnode_handle_t *dnh; 1282 1283 ASSERT(!(flag & DNODE_MUST_BE_ALLOCATED) || (slots == 0)); 1284 ASSERT(!(flag & DNODE_MUST_BE_FREE) || (slots > 0)); 1285 1286 /* 1287 * If you are holding the spa config lock as writer, you shouldn't 1288 * be asking the DMU to do *anything* unless it's the root pool 1289 * which may require us to read from the root filesystem while 1290 * holding some (not all) of the locks as writer. 1291 */ 1292 ASSERT(spa_config_held(os->os_spa, SCL_ALL, RW_WRITER) == 0 || 1293 (spa_is_root(os->os_spa) && 1294 spa_config_held(os->os_spa, SCL_STATE, RW_WRITER))); 1295 1296 ASSERT((flag & DNODE_MUST_BE_ALLOCATED) || (flag & DNODE_MUST_BE_FREE)); 1297 1298 if (object == DMU_USERUSED_OBJECT || object == DMU_GROUPUSED_OBJECT) { 1299 dn = (object == DMU_USERUSED_OBJECT) ? 1300 DMU_USERUSED_DNODE(os) : DMU_GROUPUSED_DNODE(os); 1301 if (dn == NULL) 1302 return (SET_ERROR(ENOENT)); 1303 type = dn->dn_type; 1304 if ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE) 1305 return (SET_ERROR(ENOENT)); 1306 if ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE) 1307 return (SET_ERROR(EEXIST)); 1308 DNODE_VERIFY(dn); 1309 (void) zfs_refcount_add(&dn->dn_holds, tag); 1310 *dnp = dn; 1311 return (0); 1312 } 1313 1314 if (object == 0 || object >= DN_MAX_OBJECT) 1315 return (SET_ERROR(EINVAL)); 1316 1317 mdn = DMU_META_DNODE(os); 1318 ASSERT(mdn->dn_object == DMU_META_DNODE_OBJECT); 1319 1320 DNODE_VERIFY(mdn); 1321 1322 if (!RW_WRITE_HELD(&mdn->dn_struct_rwlock)) { 1323 rw_enter(&mdn->dn_struct_rwlock, RW_READER); 1324 drop_struct_lock = TRUE; 1325 } 1326 1327 blk = dbuf_whichblock(mdn, 0, object * sizeof (dnode_phys_t)); 1328 1329 db = dbuf_hold(mdn, blk, FTAG); 1330 if (drop_struct_lock) 1331 rw_exit(&mdn->dn_struct_rwlock); 1332 if (db == NULL) { 1333 DNODE_STAT_BUMP(dnode_hold_dbuf_hold); 1334 return (SET_ERROR(EIO)); 1335 } 1336 err = dbuf_read(db, NULL, DB_RF_CANFAIL); 1337 if (err) { 1338 DNODE_STAT_BUMP(dnode_hold_dbuf_read); 1339 dbuf_rele(db, FTAG); 1340 return (err); 1341 } 1342 1343 ASSERT3U(db->db.db_size, >=, 1<<DNODE_SHIFT); 1344 epb = db->db.db_size >> DNODE_SHIFT; 1345 1346 idx = object & (epb - 1); 1347 dn_block = (dnode_phys_t *)db->db.db_data; 1348 1349 ASSERT(DB_DNODE(db)->dn_type == DMU_OT_DNODE); 1350 dnc = dmu_buf_get_user(&db->db); 1351 dnh = NULL; 1352 if (dnc == NULL) { 1353 dnode_children_t *winner; 1354 int skip = 0; 1355 1356 dnc = kmem_zalloc(sizeof (dnode_children_t) + 1357 epb * sizeof (dnode_handle_t), KM_SLEEP); 1358 dnc->dnc_count = epb; 1359 dnh = &dnc->dnc_children[0]; 1360 1361 /* Initialize dnode slot status from dnode_phys_t */ 1362 for (int i = 0; i < epb; i++) { 1363 zrl_init(&dnh[i].dnh_zrlock); 1364 1365 if (skip) { 1366 skip--; 1367 continue; 1368 } 1369 1370 if (dn_block[i].dn_type != DMU_OT_NONE) { 1371 int interior = dn_block[i].dn_extra_slots; 1372 1373 dnode_set_slots(dnc, i, 1, DN_SLOT_ALLOCATED); 1374 dnode_set_slots(dnc, i + 1, interior, 1375 DN_SLOT_INTERIOR); 1376 skip = interior; 1377 } else { 1378 dnh[i].dnh_dnode = DN_SLOT_FREE; 1379 skip = 0; 1380 } 1381 } 1382 1383 dmu_buf_init_user(&dnc->dnc_dbu, NULL, 1384 dnode_buf_evict_async, NULL); 1385 winner = dmu_buf_set_user(&db->db, &dnc->dnc_dbu); 1386 if (winner != NULL) { 1387 1388 for (int i = 0; i < epb; i++) 1389 zrl_destroy(&dnh[i].dnh_zrlock); 1390 1391 kmem_free(dnc, sizeof (dnode_children_t) + 1392 epb * sizeof (dnode_handle_t)); 1393 dnc = winner; 1394 } 1395 } 1396 1397 ASSERT(dnc->dnc_count == epb); 1398 dn = DN_SLOT_UNINIT; 1399 1400 if (flag & DNODE_MUST_BE_ALLOCATED) { 1401 slots = 1; 1402 1403 while (dn == DN_SLOT_UNINIT) { 1404 dnode_slots_hold(dnc, idx, slots); 1405 dnh = &dnc->dnc_children[idx]; 1406 1407 if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { 1408 dn = dnh->dnh_dnode; 1409 break; 1410 } else if (dnh->dnh_dnode == DN_SLOT_INTERIOR) { 1411 DNODE_STAT_BUMP(dnode_hold_alloc_interior); 1412 dnode_slots_rele(dnc, idx, slots); 1413 dbuf_rele(db, FTAG); 1414 return (SET_ERROR(EEXIST)); 1415 } else if (dnh->dnh_dnode != DN_SLOT_ALLOCATED) { 1416 DNODE_STAT_BUMP(dnode_hold_alloc_misses); 1417 dnode_slots_rele(dnc, idx, slots); 1418 dbuf_rele(db, FTAG); 1419 return (SET_ERROR(ENOENT)); 1420 } 1421 1422 dnode_slots_rele(dnc, idx, slots); 1423 if (!dnode_slots_tryenter(dnc, idx, slots)) { 1424 DNODE_STAT_BUMP(dnode_hold_alloc_lock_retry); 1425 continue; 1426 } 1427 1428 /* 1429 * Someone else won the race and called dnode_create() 1430 * after we checked DN_SLOT_IS_PTR() above but before 1431 * we acquired the lock. 1432 */ 1433 if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { 1434 DNODE_STAT_BUMP(dnode_hold_alloc_lock_misses); 1435 dn = dnh->dnh_dnode; 1436 } else { 1437 dn = dnode_create(os, dn_block + idx, db, 1438 object, dnh); 1439 } 1440 } 1441 1442 mutex_enter(&dn->dn_mtx); 1443 if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg != 0) { 1444 DNODE_STAT_BUMP(dnode_hold_alloc_type_none); 1445 mutex_exit(&dn->dn_mtx); 1446 dnode_slots_rele(dnc, idx, slots); 1447 dbuf_rele(db, FTAG); 1448 return (SET_ERROR(ENOENT)); 1449 } 1450 1451 DNODE_STAT_BUMP(dnode_hold_alloc_hits); 1452 } else if (flag & DNODE_MUST_BE_FREE) { 1453 1454 if (idx + slots - 1 >= DNODES_PER_BLOCK) { 1455 DNODE_STAT_BUMP(dnode_hold_free_overflow); 1456 dbuf_rele(db, FTAG); 1457 return (SET_ERROR(ENOSPC)); 1458 } 1459 1460 while (dn == DN_SLOT_UNINIT) { 1461 dnode_slots_hold(dnc, idx, slots); 1462 1463 if (!dnode_check_slots_free(dnc, idx, slots)) { 1464 DNODE_STAT_BUMP(dnode_hold_free_misses); 1465 dnode_slots_rele(dnc, idx, slots); 1466 dbuf_rele(db, FTAG); 1467 return (SET_ERROR(ENOSPC)); 1468 } 1469 1470 dnode_slots_rele(dnc, idx, slots); 1471 if (!dnode_slots_tryenter(dnc, idx, slots)) { 1472 DNODE_STAT_BUMP(dnode_hold_free_lock_retry); 1473 continue; 1474 } 1475 1476 if (!dnode_check_slots_free(dnc, idx, slots)) { 1477 DNODE_STAT_BUMP(dnode_hold_free_lock_misses); 1478 dnode_slots_rele(dnc, idx, slots); 1479 dbuf_rele(db, FTAG); 1480 return (SET_ERROR(ENOSPC)); 1481 } 1482 1483 /* 1484 * Allocated but otherwise free dnodes which would 1485 * be in the interior of a multi-slot dnodes need 1486 * to be freed. Single slot dnodes can be safely 1487 * re-purposed as a performance optimization. 1488 */ 1489 if (slots > 1) 1490 dnode_reclaim_slots(dnc, idx + 1, slots - 1); 1491 1492 dnh = &dnc->dnc_children[idx]; 1493 if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { 1494 dn = dnh->dnh_dnode; 1495 } else { 1496 dn = dnode_create(os, dn_block + idx, db, 1497 object, dnh); 1498 } 1499 } 1500 1501 mutex_enter(&dn->dn_mtx); 1502 if (!zfs_refcount_is_zero(&dn->dn_holds) || dn->dn_free_txg) { 1503 DNODE_STAT_BUMP(dnode_hold_free_refcount); 1504 mutex_exit(&dn->dn_mtx); 1505 dnode_slots_rele(dnc, idx, slots); 1506 dbuf_rele(db, FTAG); 1507 return (SET_ERROR(EEXIST)); 1508 } 1509 1510 dnode_set_slots(dnc, idx + 1, slots - 1, DN_SLOT_INTERIOR); 1511 DNODE_STAT_BUMP(dnode_hold_free_hits); 1512 } else { 1513 dbuf_rele(db, FTAG); 1514 return (SET_ERROR(EINVAL)); 1515 } 1516 1517 if (dn->dn_free_txg) { 1518 DNODE_STAT_BUMP(dnode_hold_free_txg); 1519 type = dn->dn_type; 1520 mutex_exit(&dn->dn_mtx); 1521 dnode_slots_rele(dnc, idx, slots); 1522 dbuf_rele(db, FTAG); 1523 return (SET_ERROR((flag & DNODE_MUST_BE_ALLOCATED) ? 1524 ENOENT : EEXIST)); 1525 } 1526 1527 if (zfs_refcount_add(&dn->dn_holds, tag) == 1) 1528 dbuf_add_ref(db, dnh); 1529 1530 mutex_exit(&dn->dn_mtx); 1531 1532 /* Now we can rely on the hold to prevent the dnode from moving. */ 1533 dnode_slots_rele(dnc, idx, slots); 1534 1535 DNODE_VERIFY(dn); 1536 ASSERT3P(dn->dn_dbuf, ==, db); 1537 ASSERT3U(dn->dn_object, ==, object); 1538 dbuf_rele(db, FTAG); 1539 1540 *dnp = dn; 1541 return (0); 1542 } 1543 1544 /* 1545 * Return held dnode if the object is allocated, NULL if not. 1546 */ 1547 int 1548 dnode_hold(objset_t *os, uint64_t object, void *tag, dnode_t **dnp) 1549 { 1550 return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, 0, tag, 1551 dnp)); 1552 } 1553 1554 /* 1555 * Can only add a reference if there is already at least one 1556 * reference on the dnode. Returns FALSE if unable to add a 1557 * new reference. 1558 */ 1559 boolean_t 1560 dnode_add_ref(dnode_t *dn, void *tag) 1561 { 1562 mutex_enter(&dn->dn_mtx); 1563 if (zfs_refcount_is_zero(&dn->dn_holds)) { 1564 mutex_exit(&dn->dn_mtx); 1565 return (FALSE); 1566 } 1567 VERIFY(1 < zfs_refcount_add(&dn->dn_holds, tag)); 1568 mutex_exit(&dn->dn_mtx); 1569 return (TRUE); 1570 } 1571 1572 void 1573 dnode_rele(dnode_t *dn, void *tag) 1574 { 1575 mutex_enter(&dn->dn_mtx); 1576 dnode_rele_and_unlock(dn, tag, B_FALSE); 1577 } 1578 1579 void 1580 dnode_rele_and_unlock(dnode_t *dn, void *tag, boolean_t evicting) 1581 { 1582 uint64_t refs; 1583 /* Get while the hold prevents the dnode from moving. */ 1584 dmu_buf_impl_t *db = dn->dn_dbuf; 1585 dnode_handle_t *dnh = dn->dn_handle; 1586 1587 refs = zfs_refcount_remove(&dn->dn_holds, tag); 1588 mutex_exit(&dn->dn_mtx); 1589 1590 /* 1591 * It's unsafe to release the last hold on a dnode by dnode_rele() or 1592 * indirectly by dbuf_rele() while relying on the dnode handle to 1593 * prevent the dnode from moving, since releasing the last hold could 1594 * result in the dnode's parent dbuf evicting its dnode handles. For 1595 * that reason anyone calling dnode_rele() or dbuf_rele() without some 1596 * other direct or indirect hold on the dnode must first drop the dnode 1597 * handle. 1598 */ 1599 ASSERT(refs > 0 || dnh->dnh_zrlock.zr_owner != curthread); 1600 1601 /* NOTE: the DNODE_DNODE does not have a dn_dbuf */ 1602 if (refs == 0 && db != NULL) { 1603 /* 1604 * Another thread could add a hold to the dnode handle in 1605 * dnode_hold_impl() while holding the parent dbuf. Since the 1606 * hold on the parent dbuf prevents the handle from being 1607 * destroyed, the hold on the handle is OK. We can't yet assert 1608 * that the handle has zero references, but that will be 1609 * asserted anyway when the handle gets destroyed. 1610 */ 1611 mutex_enter(&db->db_mtx); 1612 dbuf_rele_and_unlock(db, dnh, evicting); 1613 } 1614 } 1615 1616 void 1617 dnode_setdirty(dnode_t *dn, dmu_tx_t *tx) 1618 { 1619 objset_t *os = dn->dn_objset; 1620 uint64_t txg = tx->tx_txg; 1621 1622 if (DMU_OBJECT_IS_SPECIAL(dn->dn_object)) { 1623 dsl_dataset_dirty(os->os_dsl_dataset, tx); 1624 return; 1625 } 1626 1627 DNODE_VERIFY(dn); 1628 1629 #ifdef ZFS_DEBUG 1630 mutex_enter(&dn->dn_mtx); 1631 ASSERT(dn->dn_phys->dn_type || dn->dn_allocated_txg); 1632 ASSERT(dn->dn_free_txg == 0 || dn->dn_free_txg >= txg); 1633 mutex_exit(&dn->dn_mtx); 1634 #endif 1635 1636 /* 1637 * Determine old uid/gid when necessary 1638 */ 1639 dmu_objset_userquota_get_ids(dn, B_TRUE, tx); 1640 1641 multilist_t *dirtylist = os->os_dirty_dnodes[txg & TXG_MASK]; 1642 multilist_sublist_t *mls = multilist_sublist_lock_obj(dirtylist, dn); 1643 1644 /* 1645 * If we are already marked dirty, we're done. 1646 */ 1647 if (multilist_link_active(&dn->dn_dirty_link[txg & TXG_MASK])) { 1648 multilist_sublist_unlock(mls); 1649 return; 1650 } 1651 1652 ASSERT(!zfs_refcount_is_zero(&dn->dn_holds) || 1653 !avl_is_empty(&dn->dn_dbufs)); 1654 ASSERT(dn->dn_datablksz != 0); 1655 ASSERT0(dn->dn_next_bonuslen[txg&TXG_MASK]); 1656 ASSERT0(dn->dn_next_blksz[txg&TXG_MASK]); 1657 ASSERT0(dn->dn_next_bonustype[txg&TXG_MASK]); 1658 1659 dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n", 1660 dn->dn_object, txg); 1661 1662 multilist_sublist_insert_head(mls, dn); 1663 1664 multilist_sublist_unlock(mls); 1665 1666 /* 1667 * The dnode maintains a hold on its containing dbuf as 1668 * long as there are holds on it. Each instantiated child 1669 * dbuf maintains a hold on the dnode. When the last child 1670 * drops its hold, the dnode will drop its hold on the 1671 * containing dbuf. We add a "dirty hold" here so that the 1672 * dnode will hang around after we finish processing its 1673 * children. 1674 */ 1675 VERIFY(dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg)); 1676 1677 (void) dbuf_dirty(dn->dn_dbuf, tx); 1678 1679 dsl_dataset_dirty(os->os_dsl_dataset, tx); 1680 } 1681 1682 void 1683 dnode_free(dnode_t *dn, dmu_tx_t *tx) 1684 { 1685 mutex_enter(&dn->dn_mtx); 1686 if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg) { 1687 mutex_exit(&dn->dn_mtx); 1688 return; 1689 } 1690 dn->dn_free_txg = tx->tx_txg; 1691 mutex_exit(&dn->dn_mtx); 1692 1693 dnode_setdirty(dn, tx); 1694 } 1695 1696 /* 1697 * Try to change the block size for the indicated dnode. This can only 1698 * succeed if there are no blocks allocated or dirty beyond first block 1699 */ 1700 int 1701 dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx) 1702 { 1703 dmu_buf_impl_t *db; 1704 int err; 1705 1706 ASSERT3U(size, <=, spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); 1707 if (size == 0) 1708 size = SPA_MINBLOCKSIZE; 1709 else 1710 size = P2ROUNDUP(size, SPA_MINBLOCKSIZE); 1711 1712 if (ibs == dn->dn_indblkshift) 1713 ibs = 0; 1714 1715 if (size >> SPA_MINBLOCKSHIFT == dn->dn_datablkszsec && ibs == 0) 1716 return (0); 1717 1718 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 1719 1720 /* Check for any allocated blocks beyond the first */ 1721 if (dn->dn_maxblkid != 0) 1722 goto fail; 1723 1724 mutex_enter(&dn->dn_dbufs_mtx); 1725 for (db = avl_first(&dn->dn_dbufs); db != NULL; 1726 db = AVL_NEXT(&dn->dn_dbufs, db)) { 1727 if (db->db_blkid != 0 && db->db_blkid != DMU_BONUS_BLKID && 1728 db->db_blkid != DMU_SPILL_BLKID) { 1729 mutex_exit(&dn->dn_dbufs_mtx); 1730 goto fail; 1731 } 1732 } 1733 mutex_exit(&dn->dn_dbufs_mtx); 1734 1735 if (ibs && dn->dn_nlevels != 1) 1736 goto fail; 1737 1738 /* resize the old block */ 1739 err = dbuf_hold_impl(dn, 0, 0, TRUE, FALSE, FTAG, &db); 1740 if (err == 0) 1741 dbuf_new_size(db, size, tx); 1742 else if (err != ENOENT) 1743 goto fail; 1744 1745 dnode_setdblksz(dn, size); 1746 dnode_setdirty(dn, tx); 1747 dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = size; 1748 if (ibs) { 1749 dn->dn_indblkshift = ibs; 1750 dn->dn_next_indblkshift[tx->tx_txg&TXG_MASK] = ibs; 1751 } 1752 /* rele after we have fixed the blocksize in the dnode */ 1753 if (db) 1754 dbuf_rele(db, FTAG); 1755 1756 rw_exit(&dn->dn_struct_rwlock); 1757 return (0); 1758 1759 fail: 1760 rw_exit(&dn->dn_struct_rwlock); 1761 return (SET_ERROR(ENOTSUP)); 1762 } 1763 1764 /* read-holding callers must not rely on the lock being continuously held */ 1765 void 1766 dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx, boolean_t have_read) 1767 { 1768 uint64_t txgoff = tx->tx_txg & TXG_MASK; 1769 int epbs, new_nlevels; 1770 uint64_t sz; 1771 1772 ASSERT(blkid != DMU_BONUS_BLKID); 1773 1774 ASSERT(have_read ? 1775 RW_READ_HELD(&dn->dn_struct_rwlock) : 1776 RW_WRITE_HELD(&dn->dn_struct_rwlock)); 1777 1778 /* 1779 * if we have a read-lock, check to see if we need to do any work 1780 * before upgrading to a write-lock. 1781 */ 1782 if (have_read) { 1783 if (blkid <= dn->dn_maxblkid) 1784 return; 1785 1786 if (!rw_tryupgrade(&dn->dn_struct_rwlock)) { 1787 rw_exit(&dn->dn_struct_rwlock); 1788 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 1789 } 1790 } 1791 1792 if (blkid <= dn->dn_maxblkid) 1793 goto out; 1794 1795 dn->dn_maxblkid = blkid; 1796 1797 /* 1798 * Compute the number of levels necessary to support the new maxblkid. 1799 */ 1800 new_nlevels = 1; 1801 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1802 for (sz = dn->dn_nblkptr; 1803 sz <= blkid && sz >= dn->dn_nblkptr; sz <<= epbs) 1804 new_nlevels++; 1805 1806 if (new_nlevels > dn->dn_nlevels) { 1807 int old_nlevels = dn->dn_nlevels; 1808 dmu_buf_impl_t *db; 1809 list_t *list; 1810 dbuf_dirty_record_t *new, *dr, *dr_next; 1811 1812 dn->dn_nlevels = new_nlevels; 1813 1814 ASSERT3U(new_nlevels, >, dn->dn_next_nlevels[txgoff]); 1815 dn->dn_next_nlevels[txgoff] = new_nlevels; 1816 1817 /* dirty the left indirects */ 1818 db = dbuf_hold_level(dn, old_nlevels, 0, FTAG); 1819 ASSERT(db != NULL); 1820 new = dbuf_dirty(db, tx); 1821 dbuf_rele(db, FTAG); 1822 1823 /* transfer the dirty records to the new indirect */ 1824 mutex_enter(&dn->dn_mtx); 1825 mutex_enter(&new->dt.di.dr_mtx); 1826 list = &dn->dn_dirty_records[txgoff]; 1827 for (dr = list_head(list); dr; dr = dr_next) { 1828 dr_next = list_next(&dn->dn_dirty_records[txgoff], dr); 1829 if (dr->dr_dbuf->db_level != new_nlevels-1 && 1830 dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID && 1831 dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) { 1832 ASSERT(dr->dr_dbuf->db_level == old_nlevels-1); 1833 list_remove(&dn->dn_dirty_records[txgoff], dr); 1834 list_insert_tail(&new->dt.di.dr_children, dr); 1835 dr->dr_parent = new; 1836 } 1837 } 1838 mutex_exit(&new->dt.di.dr_mtx); 1839 mutex_exit(&dn->dn_mtx); 1840 } 1841 1842 out: 1843 if (have_read) 1844 rw_downgrade(&dn->dn_struct_rwlock); 1845 } 1846 1847 static void 1848 dnode_dirty_l1(dnode_t *dn, uint64_t l1blkid, dmu_tx_t *tx) 1849 { 1850 dmu_buf_impl_t *db = dbuf_hold_level(dn, 1, l1blkid, FTAG); 1851 if (db != NULL) { 1852 dmu_buf_will_dirty(&db->db, tx); 1853 dbuf_rele(db, FTAG); 1854 } 1855 } 1856 1857 /* 1858 * Dirty all the in-core level-1 dbufs in the range specified by start_blkid 1859 * and end_blkid. 1860 */ 1861 static void 1862 dnode_dirty_l1range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, 1863 dmu_tx_t *tx) 1864 { 1865 dmu_buf_impl_t db_search; 1866 dmu_buf_impl_t *db; 1867 avl_index_t where; 1868 1869 mutex_enter(&dn->dn_dbufs_mtx); 1870 1871 db_search.db_level = 1; 1872 db_search.db_blkid = start_blkid + 1; 1873 db_search.db_state = DB_SEARCH; 1874 for (;;) { 1875 1876 db = avl_find(&dn->dn_dbufs, &db_search, &where); 1877 if (db == NULL) 1878 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 1879 1880 if (db == NULL || db->db_level != 1 || 1881 db->db_blkid >= end_blkid) { 1882 break; 1883 } 1884 1885 /* 1886 * Setup the next blkid we want to search for. 1887 */ 1888 db_search.db_blkid = db->db_blkid + 1; 1889 ASSERT3U(db->db_blkid, >=, start_blkid); 1890 1891 /* 1892 * If the dbuf transitions to DB_EVICTING while we're trying 1893 * to dirty it, then we will be unable to discover it in 1894 * the dbuf hash table. This will result in a call to 1895 * dbuf_create() which needs to acquire the dn_dbufs_mtx 1896 * lock. To avoid a deadlock, we drop the lock before 1897 * dirtying the level-1 dbuf. 1898 */ 1899 mutex_exit(&dn->dn_dbufs_mtx); 1900 dnode_dirty_l1(dn, db->db_blkid, tx); 1901 mutex_enter(&dn->dn_dbufs_mtx); 1902 } 1903 1904 #ifdef ZFS_DEBUG 1905 /* 1906 * Walk all the in-core level-1 dbufs and verify they have been dirtied. 1907 */ 1908 db_search.db_level = 1; 1909 db_search.db_blkid = start_blkid + 1; 1910 db_search.db_state = DB_SEARCH; 1911 db = avl_find(&dn->dn_dbufs, &db_search, &where); 1912 if (db == NULL) 1913 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); 1914 for (; db != NULL; db = AVL_NEXT(&dn->dn_dbufs, db)) { 1915 if (db->db_level != 1 || db->db_blkid >= end_blkid) 1916 break; 1917 ASSERT(db->db_dirtycnt > 0); 1918 } 1919 #endif 1920 mutex_exit(&dn->dn_dbufs_mtx); 1921 } 1922 1923 void 1924 dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx) 1925 { 1926 dmu_buf_impl_t *db; 1927 uint64_t blkoff, blkid, nblks; 1928 int blksz, blkshift, head, tail; 1929 int trunc = FALSE; 1930 int epbs; 1931 1932 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 1933 blksz = dn->dn_datablksz; 1934 blkshift = dn->dn_datablkshift; 1935 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; 1936 1937 if (len == DMU_OBJECT_END) { 1938 len = UINT64_MAX - off; 1939 trunc = TRUE; 1940 } 1941 1942 /* 1943 * First, block align the region to free: 1944 */ 1945 if (ISP2(blksz)) { 1946 head = P2NPHASE(off, blksz); 1947 blkoff = P2PHASE(off, blksz); 1948 if ((off >> blkshift) > dn->dn_maxblkid) 1949 goto out; 1950 } else { 1951 ASSERT(dn->dn_maxblkid == 0); 1952 if (off == 0 && len >= blksz) { 1953 /* 1954 * Freeing the whole block; fast-track this request. 1955 */ 1956 blkid = 0; 1957 nblks = 1; 1958 if (dn->dn_nlevels > 1) 1959 dnode_dirty_l1(dn, 0, tx); 1960 goto done; 1961 } else if (off >= blksz) { 1962 /* Freeing past end-of-data */ 1963 goto out; 1964 } else { 1965 /* Freeing part of the block. */ 1966 head = blksz - off; 1967 ASSERT3U(head, >, 0); 1968 } 1969 blkoff = off; 1970 } 1971 /* zero out any partial block data at the start of the range */ 1972 if (head) { 1973 ASSERT3U(blkoff + head, ==, blksz); 1974 if (len < head) 1975 head = len; 1976 if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off), 1977 TRUE, FALSE, FTAG, &db) == 0) { 1978 caddr_t data; 1979 1980 /* don't dirty if it isn't on disk and isn't dirty */ 1981 if (db->db_last_dirty || 1982 (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) { 1983 rw_exit(&dn->dn_struct_rwlock); 1984 dmu_buf_will_dirty(&db->db, tx); 1985 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 1986 data = db->db.db_data; 1987 bzero(data + blkoff, head); 1988 } 1989 dbuf_rele(db, FTAG); 1990 } 1991 off += head; 1992 len -= head; 1993 } 1994 1995 /* If the range was less than one block, we're done */ 1996 if (len == 0) 1997 goto out; 1998 1999 /* If the remaining range is past end of file, we're done */ 2000 if ((off >> blkshift) > dn->dn_maxblkid) 2001 goto out; 2002 2003 ASSERT(ISP2(blksz)); 2004 if (trunc) 2005 tail = 0; 2006 else 2007 tail = P2PHASE(len, blksz); 2008 2009 ASSERT0(P2PHASE(off, blksz)); 2010 /* zero out any partial block data at the end of the range */ 2011 if (tail) { 2012 if (len < tail) 2013 tail = len; 2014 if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off+len), 2015 TRUE, FALSE, FTAG, &db) == 0) { 2016 /* don't dirty if not on disk and not dirty */ 2017 if (db->db_last_dirty || 2018 (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) { 2019 rw_exit(&dn->dn_struct_rwlock); 2020 dmu_buf_will_dirty(&db->db, tx); 2021 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 2022 bzero(db->db.db_data, tail); 2023 } 2024 dbuf_rele(db, FTAG); 2025 } 2026 len -= tail; 2027 } 2028 2029 /* If the range did not include a full block, we are done */ 2030 if (len == 0) 2031 goto out; 2032 2033 ASSERT(IS_P2ALIGNED(off, blksz)); 2034 ASSERT(trunc || IS_P2ALIGNED(len, blksz)); 2035 blkid = off >> blkshift; 2036 nblks = len >> blkshift; 2037 if (trunc) 2038 nblks += 1; 2039 2040 /* 2041 * Dirty all the indirect blocks in this range. Note that only 2042 * the first and last indirect blocks can actually be written 2043 * (if they were partially freed) -- they must be dirtied, even if 2044 * they do not exist on disk yet. The interior blocks will 2045 * be freed by free_children(), so they will not actually be written. 2046 * Even though these interior blocks will not be written, we 2047 * dirty them for two reasons: 2048 * 2049 * - It ensures that the indirect blocks remain in memory until 2050 * syncing context. (They have already been prefetched by 2051 * dmu_tx_hold_free(), so we don't have to worry about reading 2052 * them serially here.) 2053 * 2054 * - The dirty space accounting will put pressure on the txg sync 2055 * mechanism to begin syncing, and to delay transactions if there 2056 * is a large amount of freeing. Even though these indirect 2057 * blocks will not be written, we could need to write the same 2058 * amount of space if we copy the freed BPs into deadlists. 2059 */ 2060 if (dn->dn_nlevels > 1) { 2061 uint64_t first, last; 2062 2063 first = blkid >> epbs; 2064 dnode_dirty_l1(dn, first, tx); 2065 if (trunc) 2066 last = dn->dn_maxblkid >> epbs; 2067 else 2068 last = (blkid + nblks - 1) >> epbs; 2069 if (last != first) 2070 dnode_dirty_l1(dn, last, tx); 2071 2072 dnode_dirty_l1range(dn, first, last, tx); 2073 2074 int shift = dn->dn_datablkshift + dn->dn_indblkshift - 2075 SPA_BLKPTRSHIFT; 2076 for (uint64_t i = first + 1; i < last; i++) { 2077 /* 2078 * Set i to the blockid of the next non-hole 2079 * level-1 indirect block at or after i. Note 2080 * that dnode_next_offset() operates in terms of 2081 * level-0-equivalent bytes. 2082 */ 2083 uint64_t ibyte = i << shift; 2084 int err = dnode_next_offset(dn, DNODE_FIND_HAVELOCK, 2085 &ibyte, 2, 1, 0); 2086 i = ibyte >> shift; 2087 if (i >= last) 2088 break; 2089 2090 /* 2091 * Normally we should not see an error, either 2092 * from dnode_next_offset() or dbuf_hold_level() 2093 * (except for ESRCH from dnode_next_offset). 2094 * If there is an i/o error, then when we read 2095 * this block in syncing context, it will use 2096 * ZIO_FLAG_MUSTSUCCEED, and thus hang/panic according 2097 * to the "failmode" property. dnode_next_offset() 2098 * doesn't have a flag to indicate MUSTSUCCEED. 2099 */ 2100 if (err != 0) 2101 break; 2102 2103 dnode_dirty_l1(dn, i, tx); 2104 } 2105 } 2106 2107 done: 2108 /* 2109 * Add this range to the dnode range list. 2110 * We will finish up this free operation in the syncing phase. 2111 */ 2112 mutex_enter(&dn->dn_mtx); 2113 int txgoff = tx->tx_txg & TXG_MASK; 2114 if (dn->dn_free_ranges[txgoff] == NULL) { 2115 dn->dn_free_ranges[txgoff] = range_tree_create(NULL, NULL); 2116 } 2117 range_tree_clear(dn->dn_free_ranges[txgoff], blkid, nblks); 2118 range_tree_add(dn->dn_free_ranges[txgoff], blkid, nblks); 2119 dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n", 2120 blkid, nblks, tx->tx_txg); 2121 mutex_exit(&dn->dn_mtx); 2122 2123 dbuf_free_range(dn, blkid, blkid + nblks - 1, tx); 2124 dnode_setdirty(dn, tx); 2125 out: 2126 2127 rw_exit(&dn->dn_struct_rwlock); 2128 } 2129 2130 static boolean_t 2131 dnode_spill_freed(dnode_t *dn) 2132 { 2133 int i; 2134 2135 mutex_enter(&dn->dn_mtx); 2136 for (i = 0; i < TXG_SIZE; i++) { 2137 if (dn->dn_rm_spillblk[i] == DN_KILL_SPILLBLK) 2138 break; 2139 } 2140 mutex_exit(&dn->dn_mtx); 2141 return (i < TXG_SIZE); 2142 } 2143 2144 /* return TRUE if this blkid was freed in a recent txg, or FALSE if it wasn't */ 2145 uint64_t 2146 dnode_block_freed(dnode_t *dn, uint64_t blkid) 2147 { 2148 void *dp = spa_get_dsl(dn->dn_objset->os_spa); 2149 int i; 2150 2151 if (blkid == DMU_BONUS_BLKID) 2152 return (FALSE); 2153 2154 /* 2155 * If we're in the process of opening the pool, dp will not be 2156 * set yet, but there shouldn't be anything dirty. 2157 */ 2158 if (dp == NULL) 2159 return (FALSE); 2160 2161 if (dn->dn_free_txg) 2162 return (TRUE); 2163 2164 if (blkid == DMU_SPILL_BLKID) 2165 return (dnode_spill_freed(dn)); 2166 2167 mutex_enter(&dn->dn_mtx); 2168 for (i = 0; i < TXG_SIZE; i++) { 2169 if (dn->dn_free_ranges[i] != NULL && 2170 range_tree_contains(dn->dn_free_ranges[i], blkid, 1)) 2171 break; 2172 } 2173 mutex_exit(&dn->dn_mtx); 2174 return (i < TXG_SIZE); 2175 } 2176 2177 /* call from syncing context when we actually write/free space for this dnode */ 2178 void 2179 dnode_diduse_space(dnode_t *dn, int64_t delta) 2180 { 2181 uint64_t space; 2182 dprintf_dnode(dn, "dn=%p dnp=%p used=%llu delta=%lld\n", 2183 dn, dn->dn_phys, 2184 (u_longlong_t)dn->dn_phys->dn_used, 2185 (longlong_t)delta); 2186 2187 mutex_enter(&dn->dn_mtx); 2188 space = DN_USED_BYTES(dn->dn_phys); 2189 if (delta > 0) { 2190 ASSERT3U(space + delta, >=, space); /* no overflow */ 2191 } else { 2192 ASSERT3U(space, >=, -delta); /* no underflow */ 2193 } 2194 space += delta; 2195 if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_DNODE_BYTES) { 2196 ASSERT((dn->dn_phys->dn_flags & DNODE_FLAG_USED_BYTES) == 0); 2197 ASSERT0(P2PHASE(space, 1<<DEV_BSHIFT)); 2198 dn->dn_phys->dn_used = space >> DEV_BSHIFT; 2199 } else { 2200 dn->dn_phys->dn_used = space; 2201 dn->dn_phys->dn_flags |= DNODE_FLAG_USED_BYTES; 2202 } 2203 mutex_exit(&dn->dn_mtx); 2204 } 2205 2206 /* 2207 * Scans a block at the indicated "level" looking for a hole or data, 2208 * depending on 'flags'. 2209 * 2210 * If level > 0, then we are scanning an indirect block looking at its 2211 * pointers. If level == 0, then we are looking at a block of dnodes. 2212 * 2213 * If we don't find what we are looking for in the block, we return ESRCH. 2214 * Otherwise, return with *offset pointing to the beginning (if searching 2215 * forwards) or end (if searching backwards) of the range covered by the 2216 * block pointer we matched on (or dnode). 2217 * 2218 * The basic search algorithm used below by dnode_next_offset() is to 2219 * use this function to search up the block tree (widen the search) until 2220 * we find something (i.e., we don't return ESRCH) and then search back 2221 * down the tree (narrow the search) until we reach our original search 2222 * level. 2223 */ 2224 static int 2225 dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset, 2226 int lvl, uint64_t blkfill, uint64_t txg) 2227 { 2228 dmu_buf_impl_t *db = NULL; 2229 void *data = NULL; 2230 uint64_t epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 2231 uint64_t epb = 1ULL << epbs; 2232 uint64_t minfill, maxfill; 2233 boolean_t hole; 2234 int i, inc, error, span; 2235 2236 dprintf("probing object %llu offset %llx level %d of %u\n", 2237 dn->dn_object, *offset, lvl, dn->dn_phys->dn_nlevels); 2238 2239 hole = ((flags & DNODE_FIND_HOLE) != 0); 2240 inc = (flags & DNODE_FIND_BACKWARDS) ? -1 : 1; 2241 ASSERT(txg == 0 || !hole); 2242 2243 if (lvl == dn->dn_phys->dn_nlevels) { 2244 error = 0; 2245 epb = dn->dn_phys->dn_nblkptr; 2246 data = dn->dn_phys->dn_blkptr; 2247 } else { 2248 uint64_t blkid = dbuf_whichblock(dn, lvl, *offset); 2249 error = dbuf_hold_impl(dn, lvl, blkid, TRUE, FALSE, FTAG, &db); 2250 if (error) { 2251 if (error != ENOENT) 2252 return (error); 2253 if (hole) 2254 return (0); 2255 /* 2256 * This can only happen when we are searching up 2257 * the block tree for data. We don't really need to 2258 * adjust the offset, as we will just end up looking 2259 * at the pointer to this block in its parent, and its 2260 * going to be unallocated, so we will skip over it. 2261 */ 2262 return (SET_ERROR(ESRCH)); 2263 } 2264 error = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_HAVESTRUCT); 2265 if (error) { 2266 dbuf_rele(db, FTAG); 2267 return (error); 2268 } 2269 data = db->db.db_data; 2270 } 2271 2272 2273 if (db != NULL && txg != 0 && (db->db_blkptr == NULL || 2274 db->db_blkptr->blk_birth <= txg || 2275 BP_IS_HOLE(db->db_blkptr))) { 2276 /* 2277 * This can only happen when we are searching up the tree 2278 * and these conditions mean that we need to keep climbing. 2279 */ 2280 error = SET_ERROR(ESRCH); 2281 } else if (lvl == 0) { 2282 dnode_phys_t *dnp = data; 2283 2284 ASSERT(dn->dn_type == DMU_OT_DNODE); 2285 ASSERT(!(flags & DNODE_FIND_BACKWARDS)); 2286 2287 for (i = (*offset >> DNODE_SHIFT) & (blkfill - 1); 2288 i < blkfill; i += dnp[i].dn_extra_slots + 1) { 2289 if ((dnp[i].dn_type == DMU_OT_NONE) == hole) 2290 break; 2291 } 2292 2293 if (i == blkfill) 2294 error = SET_ERROR(ESRCH); 2295 2296 *offset = (*offset & ~(DNODE_BLOCK_SIZE - 1)) + 2297 (i << DNODE_SHIFT); 2298 } else { 2299 blkptr_t *bp = data; 2300 uint64_t start = *offset; 2301 span = (lvl - 1) * epbs + dn->dn_datablkshift; 2302 minfill = 0; 2303 maxfill = blkfill << ((lvl - 1) * epbs); 2304 2305 if (hole) 2306 maxfill--; 2307 else 2308 minfill++; 2309 2310 *offset = *offset >> span; 2311 for (i = BF64_GET(*offset, 0, epbs); 2312 i >= 0 && i < epb; i += inc) { 2313 if (BP_GET_FILL(&bp[i]) >= minfill && 2314 BP_GET_FILL(&bp[i]) <= maxfill && 2315 (hole || bp[i].blk_birth > txg)) 2316 break; 2317 if (inc > 0 || *offset > 0) 2318 *offset += inc; 2319 } 2320 *offset = *offset << span; 2321 if (inc < 0) { 2322 /* traversing backwards; position offset at the end */ 2323 ASSERT3U(*offset, <=, start); 2324 *offset = MIN(*offset + (1ULL << span) - 1, start); 2325 } else if (*offset < start) { 2326 *offset = start; 2327 } 2328 if (i < 0 || i >= epb) 2329 error = SET_ERROR(ESRCH); 2330 } 2331 2332 if (db) 2333 dbuf_rele(db, FTAG); 2334 2335 return (error); 2336 } 2337 2338 /* 2339 * Find the next hole, data, or sparse region at or after *offset. 2340 * The value 'blkfill' tells us how many items we expect to find 2341 * in an L0 data block; this value is 1 for normal objects, 2342 * DNODES_PER_BLOCK for the meta dnode, and some fraction of 2343 * DNODES_PER_BLOCK when searching for sparse regions thereof. 2344 * 2345 * Examples: 2346 * 2347 * dnode_next_offset(dn, flags, offset, 1, 1, 0); 2348 * Finds the next/previous hole/data in a file. 2349 * Used in dmu_offset_next(). 2350 * 2351 * dnode_next_offset(mdn, flags, offset, 0, DNODES_PER_BLOCK, txg); 2352 * Finds the next free/allocated dnode an objset's meta-dnode. 2353 * Only finds objects that have new contents since txg (ie. 2354 * bonus buffer changes and content removal are ignored). 2355 * Used in dmu_object_next(). 2356 * 2357 * dnode_next_offset(mdn, DNODE_FIND_HOLE, offset, 2, DNODES_PER_BLOCK >> 2, 0); 2358 * Finds the next L2 meta-dnode bp that's at most 1/4 full. 2359 * Used in dmu_object_alloc(). 2360 */ 2361 int 2362 dnode_next_offset(dnode_t *dn, int flags, uint64_t *offset, 2363 int minlvl, uint64_t blkfill, uint64_t txg) 2364 { 2365 uint64_t initial_offset = *offset; 2366 int lvl, maxlvl; 2367 int error = 0; 2368 2369 if (!(flags & DNODE_FIND_HAVELOCK)) 2370 rw_enter(&dn->dn_struct_rwlock, RW_READER); 2371 2372 if (dn->dn_phys->dn_nlevels == 0) { 2373 error = SET_ERROR(ESRCH); 2374 goto out; 2375 } 2376 2377 if (dn->dn_datablkshift == 0) { 2378 if (*offset < dn->dn_datablksz) { 2379 if (flags & DNODE_FIND_HOLE) 2380 *offset = dn->dn_datablksz; 2381 } else { 2382 error = SET_ERROR(ESRCH); 2383 } 2384 goto out; 2385 } 2386 2387 maxlvl = dn->dn_phys->dn_nlevels; 2388 2389 for (lvl = minlvl; lvl <= maxlvl; lvl++) { 2390 error = dnode_next_offset_level(dn, 2391 flags, offset, lvl, blkfill, txg); 2392 if (error != ESRCH) 2393 break; 2394 } 2395 2396 while (error == 0 && --lvl >= minlvl) { 2397 error = dnode_next_offset_level(dn, 2398 flags, offset, lvl, blkfill, txg); 2399 } 2400 2401 /* 2402 * There's always a "virtual hole" at the end of the object, even 2403 * if all BP's which physically exist are non-holes. 2404 */ 2405 if ((flags & DNODE_FIND_HOLE) && error == ESRCH && txg == 0 && 2406 minlvl == 1 && blkfill == 1 && !(flags & DNODE_FIND_BACKWARDS)) { 2407 error = 0; 2408 } 2409 2410 if (error == 0 && (flags & DNODE_FIND_BACKWARDS ? 2411 initial_offset < *offset : initial_offset > *offset)) 2412 error = SET_ERROR(ESRCH); 2413 out: 2414 if (!(flags & DNODE_FIND_HAVELOCK)) 2415 rw_exit(&dn->dn_struct_rwlock); 2416 2417 return (error); 2418 } 2419