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 2009 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #include <sys/zfs_context.h> 27 #include <sys/spa.h> 28 #include <sys/dmu.h> 29 #include <sys/zio.h> 30 #include <sys/space_map.h> 31 32 /* 33 * Space map routines. 34 * NOTE: caller is responsible for all locking. 35 */ 36 static int 37 space_map_seg_compare(const void *x1, const void *x2) 38 { 39 const space_seg_t *s1 = x1; 40 const space_seg_t *s2 = x2; 41 42 if (s1->ss_start < s2->ss_start) { 43 if (s1->ss_end > s2->ss_start) 44 return (0); 45 return (-1); 46 } 47 if (s1->ss_start > s2->ss_start) { 48 if (s1->ss_start < s2->ss_end) 49 return (0); 50 return (1); 51 } 52 return (0); 53 } 54 55 void 56 space_map_create(space_map_t *sm, uint64_t start, uint64_t size, uint8_t shift, 57 kmutex_t *lp) 58 { 59 bzero(sm, sizeof (*sm)); 60 61 cv_init(&sm->sm_load_cv, NULL, CV_DEFAULT, NULL); 62 63 avl_create(&sm->sm_root, space_map_seg_compare, 64 sizeof (space_seg_t), offsetof(struct space_seg, ss_node)); 65 66 sm->sm_start = start; 67 sm->sm_size = size; 68 sm->sm_shift = shift; 69 sm->sm_lock = lp; 70 } 71 72 void 73 space_map_destroy(space_map_t *sm) 74 { 75 ASSERT(!sm->sm_loaded && !sm->sm_loading); 76 VERIFY3U(sm->sm_space, ==, 0); 77 avl_destroy(&sm->sm_root); 78 cv_destroy(&sm->sm_load_cv); 79 } 80 81 void 82 space_map_add(space_map_t *sm, uint64_t start, uint64_t size) 83 { 84 avl_index_t where; 85 space_seg_t ssearch, *ss_before, *ss_after, *ss; 86 uint64_t end = start + size; 87 int merge_before, merge_after; 88 89 ASSERT(MUTEX_HELD(sm->sm_lock)); 90 VERIFY(size != 0); 91 VERIFY3U(start, >=, sm->sm_start); 92 VERIFY3U(end, <=, sm->sm_start + sm->sm_size); 93 VERIFY(sm->sm_space + size <= sm->sm_size); 94 VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0); 95 VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0); 96 97 ssearch.ss_start = start; 98 ssearch.ss_end = end; 99 ss = avl_find(&sm->sm_root, &ssearch, &where); 100 101 if (ss != NULL && ss->ss_start <= start && ss->ss_end >= end) { 102 zfs_panic_recover("zfs: allocating allocated segment" 103 "(offset=%llu size=%llu)\n", 104 (longlong_t)start, (longlong_t)size); 105 return; 106 } 107 108 /* Make sure we don't overlap with either of our neighbors */ 109 VERIFY(ss == NULL); 110 111 ss_before = avl_nearest(&sm->sm_root, where, AVL_BEFORE); 112 ss_after = avl_nearest(&sm->sm_root, where, AVL_AFTER); 113 114 merge_before = (ss_before != NULL && ss_before->ss_end == start); 115 merge_after = (ss_after != NULL && ss_after->ss_start == end); 116 117 if (merge_before && merge_after) { 118 avl_remove(&sm->sm_root, ss_before); 119 if (sm->sm_pp_root) { 120 avl_remove(sm->sm_pp_root, ss_before); 121 avl_remove(sm->sm_pp_root, ss_after); 122 } 123 ss_after->ss_start = ss_before->ss_start; 124 kmem_free(ss_before, sizeof (*ss_before)); 125 ss = ss_after; 126 } else if (merge_before) { 127 ss_before->ss_end = end; 128 if (sm->sm_pp_root) 129 avl_remove(sm->sm_pp_root, ss_before); 130 ss = ss_before; 131 } else if (merge_after) { 132 ss_after->ss_start = start; 133 if (sm->sm_pp_root) 134 avl_remove(sm->sm_pp_root, ss_after); 135 ss = ss_after; 136 } else { 137 ss = kmem_alloc(sizeof (*ss), KM_SLEEP); 138 ss->ss_start = start; 139 ss->ss_end = end; 140 avl_insert(&sm->sm_root, ss, where); 141 } 142 143 if (sm->sm_pp_root) 144 avl_add(sm->sm_pp_root, ss); 145 146 sm->sm_space += size; 147 } 148 149 void 150 space_map_remove(space_map_t *sm, uint64_t start, uint64_t size) 151 { 152 avl_index_t where; 153 space_seg_t ssearch, *ss, *newseg; 154 uint64_t end = start + size; 155 int left_over, right_over; 156 157 ASSERT(MUTEX_HELD(sm->sm_lock)); 158 VERIFY(size != 0); 159 VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0); 160 VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0); 161 162 ssearch.ss_start = start; 163 ssearch.ss_end = end; 164 ss = avl_find(&sm->sm_root, &ssearch, &where); 165 166 /* Make sure we completely overlap with someone */ 167 if (ss == NULL) { 168 zfs_panic_recover("zfs: freeing free segment " 169 "(offset=%llu size=%llu)", 170 (longlong_t)start, (longlong_t)size); 171 return; 172 } 173 VERIFY3U(ss->ss_start, <=, start); 174 VERIFY3U(ss->ss_end, >=, end); 175 VERIFY(sm->sm_space - size <= sm->sm_size); 176 177 left_over = (ss->ss_start != start); 178 right_over = (ss->ss_end != end); 179 180 if (sm->sm_pp_root) 181 avl_remove(sm->sm_pp_root, ss); 182 183 if (left_over && right_over) { 184 newseg = kmem_alloc(sizeof (*newseg), KM_SLEEP); 185 newseg->ss_start = end; 186 newseg->ss_end = ss->ss_end; 187 ss->ss_end = start; 188 avl_insert_here(&sm->sm_root, newseg, ss, AVL_AFTER); 189 if (sm->sm_pp_root) 190 avl_add(sm->sm_pp_root, newseg); 191 } else if (left_over) { 192 ss->ss_end = start; 193 } else if (right_over) { 194 ss->ss_start = end; 195 } else { 196 avl_remove(&sm->sm_root, ss); 197 kmem_free(ss, sizeof (*ss)); 198 ss = NULL; 199 } 200 201 if (sm->sm_pp_root && ss != NULL) 202 avl_add(sm->sm_pp_root, ss); 203 204 sm->sm_space -= size; 205 } 206 207 boolean_t 208 space_map_contains(space_map_t *sm, uint64_t start, uint64_t size) 209 { 210 avl_index_t where; 211 space_seg_t ssearch, *ss; 212 uint64_t end = start + size; 213 214 ASSERT(MUTEX_HELD(sm->sm_lock)); 215 VERIFY(size != 0); 216 VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0); 217 VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0); 218 219 ssearch.ss_start = start; 220 ssearch.ss_end = end; 221 ss = avl_find(&sm->sm_root, &ssearch, &where); 222 223 return (ss != NULL && ss->ss_start <= start && ss->ss_end >= end); 224 } 225 226 void 227 space_map_vacate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest) 228 { 229 space_seg_t *ss; 230 void *cookie = NULL; 231 232 ASSERT(MUTEX_HELD(sm->sm_lock)); 233 234 while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) { 235 if (func != NULL) 236 func(mdest, ss->ss_start, ss->ss_end - ss->ss_start); 237 kmem_free(ss, sizeof (*ss)); 238 } 239 sm->sm_space = 0; 240 } 241 242 void 243 space_map_walk(space_map_t *sm, space_map_func_t *func, space_map_t *mdest) 244 { 245 space_seg_t *ss; 246 247 ASSERT(MUTEX_HELD(sm->sm_lock)); 248 249 for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss)) 250 func(mdest, ss->ss_start, ss->ss_end - ss->ss_start); 251 } 252 253 /* 254 * Wait for any in-progress space_map_load() to complete. 255 */ 256 void 257 space_map_load_wait(space_map_t *sm) 258 { 259 ASSERT(MUTEX_HELD(sm->sm_lock)); 260 261 while (sm->sm_loading) { 262 ASSERT(!sm->sm_loaded); 263 cv_wait(&sm->sm_load_cv, sm->sm_lock); 264 } 265 } 266 267 /* 268 * Note: space_map_load() will drop sm_lock across dmu_read() calls. 269 * The caller must be OK with this. 270 */ 271 int 272 space_map_load(space_map_t *sm, space_map_ops_t *ops, uint8_t maptype, 273 space_map_obj_t *smo, objset_t *os) 274 { 275 uint64_t *entry, *entry_map, *entry_map_end; 276 uint64_t bufsize, size, offset, end, space; 277 uint64_t mapstart = sm->sm_start; 278 int error = 0; 279 280 ASSERT(MUTEX_HELD(sm->sm_lock)); 281 ASSERT(!sm->sm_loaded); 282 ASSERT(!sm->sm_loading); 283 284 sm->sm_loading = B_TRUE; 285 end = smo->smo_objsize; 286 space = smo->smo_alloc; 287 288 ASSERT(sm->sm_ops == NULL); 289 VERIFY3U(sm->sm_space, ==, 0); 290 291 if (maptype == SM_FREE) { 292 space_map_add(sm, sm->sm_start, sm->sm_size); 293 space = sm->sm_size - space; 294 } 295 296 bufsize = 1ULL << SPACE_MAP_BLOCKSHIFT; 297 entry_map = zio_buf_alloc(bufsize); 298 299 mutex_exit(sm->sm_lock); 300 if (end > bufsize) 301 dmu_prefetch(os, smo->smo_object, bufsize, end - bufsize); 302 mutex_enter(sm->sm_lock); 303 304 for (offset = 0; offset < end; offset += bufsize) { 305 size = MIN(end - offset, bufsize); 306 VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0); 307 VERIFY(size != 0); 308 309 dprintf("object=%llu offset=%llx size=%llx\n", 310 smo->smo_object, offset, size); 311 312 mutex_exit(sm->sm_lock); 313 error = dmu_read(os, smo->smo_object, offset, size, entry_map, 314 DMU_READ_PREFETCH); 315 mutex_enter(sm->sm_lock); 316 if (error != 0) 317 break; 318 319 entry_map_end = entry_map + (size / sizeof (uint64_t)); 320 for (entry = entry_map; entry < entry_map_end; entry++) { 321 uint64_t e = *entry; 322 323 if (SM_DEBUG_DECODE(e)) /* Skip debug entries */ 324 continue; 325 326 (SM_TYPE_DECODE(e) == maptype ? 327 space_map_add : space_map_remove)(sm, 328 (SM_OFFSET_DECODE(e) << sm->sm_shift) + mapstart, 329 SM_RUN_DECODE(e) << sm->sm_shift); 330 } 331 } 332 333 if (error == 0) { 334 VERIFY3U(sm->sm_space, ==, space); 335 336 sm->sm_loaded = B_TRUE; 337 sm->sm_ops = ops; 338 if (ops != NULL) 339 ops->smop_load(sm); 340 } else { 341 space_map_vacate(sm, NULL, NULL); 342 } 343 344 zio_buf_free(entry_map, bufsize); 345 346 sm->sm_loading = B_FALSE; 347 348 cv_broadcast(&sm->sm_load_cv); 349 350 return (error); 351 } 352 353 void 354 space_map_unload(space_map_t *sm) 355 { 356 ASSERT(MUTEX_HELD(sm->sm_lock)); 357 358 if (sm->sm_loaded && sm->sm_ops != NULL) 359 sm->sm_ops->smop_unload(sm); 360 361 sm->sm_loaded = B_FALSE; 362 sm->sm_ops = NULL; 363 364 space_map_vacate(sm, NULL, NULL); 365 } 366 367 uint64_t 368 space_map_maxsize(space_map_t *sm) 369 { 370 ASSERT(sm->sm_ops != NULL); 371 return (sm->sm_ops->smop_max(sm)); 372 } 373 374 uint64_t 375 space_map_alloc(space_map_t *sm, uint64_t size) 376 { 377 uint64_t start; 378 379 start = sm->sm_ops->smop_alloc(sm, size); 380 if (start != -1ULL) 381 space_map_remove(sm, start, size); 382 return (start); 383 } 384 385 void 386 space_map_claim(space_map_t *sm, uint64_t start, uint64_t size) 387 { 388 sm->sm_ops->smop_claim(sm, start, size); 389 space_map_remove(sm, start, size); 390 } 391 392 void 393 space_map_free(space_map_t *sm, uint64_t start, uint64_t size) 394 { 395 space_map_add(sm, start, size); 396 sm->sm_ops->smop_free(sm, start, size); 397 } 398 399 /* 400 * Note: space_map_sync() will drop sm_lock across dmu_write() calls. 401 */ 402 void 403 space_map_sync(space_map_t *sm, uint8_t maptype, 404 space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx) 405 { 406 spa_t *spa = dmu_objset_spa(os); 407 void *cookie = NULL; 408 space_seg_t *ss; 409 uint64_t bufsize, start, size, run_len; 410 uint64_t *entry, *entry_map, *entry_map_end; 411 412 ASSERT(MUTEX_HELD(sm->sm_lock)); 413 414 if (sm->sm_space == 0) 415 return; 416 417 dprintf("object %4llu, txg %llu, pass %d, %c, count %lu, space %llx\n", 418 smo->smo_object, dmu_tx_get_txg(tx), spa_sync_pass(spa), 419 maptype == SM_ALLOC ? 'A' : 'F', avl_numnodes(&sm->sm_root), 420 sm->sm_space); 421 422 if (maptype == SM_ALLOC) 423 smo->smo_alloc += sm->sm_space; 424 else 425 smo->smo_alloc -= sm->sm_space; 426 427 bufsize = (8 + avl_numnodes(&sm->sm_root)) * sizeof (uint64_t); 428 bufsize = MIN(bufsize, 1ULL << SPACE_MAP_BLOCKSHIFT); 429 entry_map = zio_buf_alloc(bufsize); 430 entry_map_end = entry_map + (bufsize / sizeof (uint64_t)); 431 entry = entry_map; 432 433 *entry++ = SM_DEBUG_ENCODE(1) | 434 SM_DEBUG_ACTION_ENCODE(maptype) | 435 SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) | 436 SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx)); 437 438 while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) { 439 size = ss->ss_end - ss->ss_start; 440 start = (ss->ss_start - sm->sm_start) >> sm->sm_shift; 441 442 sm->sm_space -= size; 443 size >>= sm->sm_shift; 444 445 while (size) { 446 run_len = MIN(size, SM_RUN_MAX); 447 448 if (entry == entry_map_end) { 449 mutex_exit(sm->sm_lock); 450 dmu_write(os, smo->smo_object, smo->smo_objsize, 451 bufsize, entry_map, tx); 452 mutex_enter(sm->sm_lock); 453 smo->smo_objsize += bufsize; 454 entry = entry_map; 455 } 456 457 *entry++ = SM_OFFSET_ENCODE(start) | 458 SM_TYPE_ENCODE(maptype) | 459 SM_RUN_ENCODE(run_len); 460 461 start += run_len; 462 size -= run_len; 463 } 464 kmem_free(ss, sizeof (*ss)); 465 } 466 467 if (entry != entry_map) { 468 size = (entry - entry_map) * sizeof (uint64_t); 469 mutex_exit(sm->sm_lock); 470 dmu_write(os, smo->smo_object, smo->smo_objsize, 471 size, entry_map, tx); 472 mutex_enter(sm->sm_lock); 473 smo->smo_objsize += size; 474 } 475 476 zio_buf_free(entry_map, bufsize); 477 478 VERIFY3U(sm->sm_space, ==, 0); 479 } 480 481 void 482 space_map_truncate(space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx) 483 { 484 VERIFY(dmu_free_range(os, smo->smo_object, 0, -1ULL, tx) == 0); 485 486 smo->smo_objsize = 0; 487 smo->smo_alloc = 0; 488 } 489 490 /* 491 * Space map reference trees. 492 * 493 * A space map is a collection of integers. Every integer is either 494 * in the map, or it's not. A space map reference tree generalizes 495 * the idea: it allows its members to have arbitrary reference counts, 496 * as opposed to the implicit reference count of 0 or 1 in a space map. 497 * This representation comes in handy when computing the union or 498 * intersection of multiple space maps. For example, the union of 499 * N space maps is the subset of the reference tree with refcnt >= 1. 500 * The intersection of N space maps is the subset with refcnt >= N. 501 * 502 * [It's very much like a Fourier transform. Unions and intersections 503 * are hard to perform in the 'space map domain', so we convert the maps 504 * into the 'reference count domain', where it's trivial, then invert.] 505 * 506 * vdev_dtl_reassess() uses computations of this form to determine 507 * DTL_MISSING and DTL_OUTAGE for interior vdevs -- e.g. a RAID-Z vdev 508 * has an outage wherever refcnt >= vdev_nparity + 1, and a mirror vdev 509 * has an outage wherever refcnt >= vdev_children. 510 */ 511 static int 512 space_map_ref_compare(const void *x1, const void *x2) 513 { 514 const space_ref_t *sr1 = x1; 515 const space_ref_t *sr2 = x2; 516 517 if (sr1->sr_offset < sr2->sr_offset) 518 return (-1); 519 if (sr1->sr_offset > sr2->sr_offset) 520 return (1); 521 522 if (sr1 < sr2) 523 return (-1); 524 if (sr1 > sr2) 525 return (1); 526 527 return (0); 528 } 529 530 void 531 space_map_ref_create(avl_tree_t *t) 532 { 533 avl_create(t, space_map_ref_compare, 534 sizeof (space_ref_t), offsetof(space_ref_t, sr_node)); 535 } 536 537 void 538 space_map_ref_destroy(avl_tree_t *t) 539 { 540 space_ref_t *sr; 541 void *cookie = NULL; 542 543 while ((sr = avl_destroy_nodes(t, &cookie)) != NULL) 544 kmem_free(sr, sizeof (*sr)); 545 546 avl_destroy(t); 547 } 548 549 static void 550 space_map_ref_add_node(avl_tree_t *t, uint64_t offset, int64_t refcnt) 551 { 552 space_ref_t *sr; 553 554 sr = kmem_alloc(sizeof (*sr), KM_SLEEP); 555 sr->sr_offset = offset; 556 sr->sr_refcnt = refcnt; 557 558 avl_add(t, sr); 559 } 560 561 void 562 space_map_ref_add_seg(avl_tree_t *t, uint64_t start, uint64_t end, 563 int64_t refcnt) 564 { 565 space_map_ref_add_node(t, start, refcnt); 566 space_map_ref_add_node(t, end, -refcnt); 567 } 568 569 /* 570 * Convert (or add) a space map into a reference tree. 571 */ 572 void 573 space_map_ref_add_map(avl_tree_t *t, space_map_t *sm, int64_t refcnt) 574 { 575 space_seg_t *ss; 576 577 ASSERT(MUTEX_HELD(sm->sm_lock)); 578 579 for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss)) 580 space_map_ref_add_seg(t, ss->ss_start, ss->ss_end, refcnt); 581 } 582 583 /* 584 * Convert a reference tree into a space map. The space map will contain 585 * all members of the reference tree for which refcnt >= minref. 586 */ 587 void 588 space_map_ref_generate_map(avl_tree_t *t, space_map_t *sm, int64_t minref) 589 { 590 uint64_t start = -1ULL; 591 int64_t refcnt = 0; 592 space_ref_t *sr; 593 594 ASSERT(MUTEX_HELD(sm->sm_lock)); 595 596 space_map_vacate(sm, NULL, NULL); 597 598 for (sr = avl_first(t); sr != NULL; sr = AVL_NEXT(t, sr)) { 599 refcnt += sr->sr_refcnt; 600 if (refcnt >= minref) { 601 if (start == -1ULL) { 602 start = sr->sr_offset; 603 } 604 } else { 605 if (start != -1ULL) { 606 uint64_t end = sr->sr_offset; 607 ASSERT(start <= end); 608 if (end > start) 609 space_map_add(sm, start, end - start); 610 start = -1ULL; 611 } 612 } 613 } 614 ASSERT(refcnt == 0); 615 ASSERT(start == -1ULL); 616 } 617