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 cv_wait(&sm->sm_load_cv, sm->sm_lock); 263 } 264 265 /* 266 * Note: space_map_load() will drop sm_lock across dmu_read() calls. 267 * The caller must be OK with this. 268 */ 269 int 270 space_map_load(space_map_t *sm, space_map_ops_t *ops, uint8_t maptype, 271 space_map_obj_t *smo, objset_t *os) 272 { 273 uint64_t *entry, *entry_map, *entry_map_end; 274 uint64_t bufsize, size, offset, end, space; 275 uint64_t mapstart = sm->sm_start; 276 int error = 0; 277 278 ASSERT(MUTEX_HELD(sm->sm_lock)); 279 280 space_map_load_wait(sm); 281 282 if (sm->sm_loaded) 283 return (0); 284 285 sm->sm_loading = B_TRUE; 286 end = smo->smo_objsize; 287 space = smo->smo_alloc; 288 289 ASSERT(sm->sm_ops == NULL); 290 VERIFY3U(sm->sm_space, ==, 0); 291 292 if (maptype == SM_FREE) { 293 space_map_add(sm, sm->sm_start, sm->sm_size); 294 space = sm->sm_size - space; 295 } 296 297 bufsize = 1ULL << SPACE_MAP_BLOCKSHIFT; 298 entry_map = zio_buf_alloc(bufsize); 299 300 mutex_exit(sm->sm_lock); 301 if (end > bufsize) 302 dmu_prefetch(os, smo->smo_object, bufsize, end - bufsize); 303 mutex_enter(sm->sm_lock); 304 305 for (offset = 0; offset < end; offset += bufsize) { 306 size = MIN(end - offset, bufsize); 307 VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0); 308 VERIFY(size != 0); 309 310 dprintf("object=%llu offset=%llx size=%llx\n", 311 smo->smo_object, offset, size); 312 313 mutex_exit(sm->sm_lock); 314 error = dmu_read(os, smo->smo_object, offset, size, entry_map, 315 DMU_READ_PREFETCH); 316 mutex_enter(sm->sm_lock); 317 if (error != 0) 318 break; 319 320 entry_map_end = entry_map + (size / sizeof (uint64_t)); 321 for (entry = entry_map; entry < entry_map_end; entry++) { 322 uint64_t e = *entry; 323 324 if (SM_DEBUG_DECODE(e)) /* Skip debug entries */ 325 continue; 326 327 (SM_TYPE_DECODE(e) == maptype ? 328 space_map_add : space_map_remove)(sm, 329 (SM_OFFSET_DECODE(e) << sm->sm_shift) + mapstart, 330 SM_RUN_DECODE(e) << sm->sm_shift); 331 } 332 } 333 334 if (error == 0) { 335 VERIFY3U(sm->sm_space, ==, space); 336 337 sm->sm_loaded = B_TRUE; 338 sm->sm_ops = ops; 339 if (ops != NULL) 340 ops->smop_load(sm); 341 } else { 342 if (ops != NULL) 343 ops->smop_unload(sm); 344 sm->sm_ops = NULL; 345 space_map_vacate(sm, NULL, NULL); 346 } 347 348 zio_buf_free(entry_map, bufsize); 349 350 sm->sm_loading = B_FALSE; 351 352 cv_broadcast(&sm->sm_load_cv); 353 354 return (error); 355 } 356 357 void 358 space_map_unload(space_map_t *sm) 359 { 360 ASSERT(MUTEX_HELD(sm->sm_lock)); 361 362 if (sm->sm_loaded && sm->sm_ops != NULL) 363 sm->sm_ops->smop_unload(sm); 364 365 sm->sm_loaded = B_FALSE; 366 sm->sm_ops = NULL; 367 368 space_map_vacate(sm, NULL, NULL); 369 } 370 371 uint64_t 372 space_map_maxsize(space_map_t *sm) 373 { 374 if (sm->sm_loaded && sm->sm_ops != NULL) 375 return (sm->sm_ops->smop_max(sm)); 376 else 377 return (-1ULL); 378 } 379 380 uint64_t 381 space_map_alloc(space_map_t *sm, uint64_t size) 382 { 383 uint64_t start; 384 385 start = sm->sm_ops->smop_alloc(sm, size); 386 if (start != -1ULL) 387 space_map_remove(sm, start, size); 388 return (start); 389 } 390 391 void 392 space_map_claim(space_map_t *sm, uint64_t start, uint64_t size) 393 { 394 sm->sm_ops->smop_claim(sm, start, size); 395 space_map_remove(sm, start, size); 396 } 397 398 void 399 space_map_free(space_map_t *sm, uint64_t start, uint64_t size) 400 { 401 space_map_add(sm, start, size); 402 sm->sm_ops->smop_free(sm, start, size); 403 } 404 405 /* 406 * Note: space_map_sync() will drop sm_lock across dmu_write() calls. 407 */ 408 void 409 space_map_sync(space_map_t *sm, uint8_t maptype, 410 space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx) 411 { 412 spa_t *spa = dmu_objset_spa(os); 413 void *cookie = NULL; 414 space_seg_t *ss; 415 uint64_t bufsize, start, size, run_len; 416 uint64_t *entry, *entry_map, *entry_map_end; 417 418 ASSERT(MUTEX_HELD(sm->sm_lock)); 419 420 if (sm->sm_space == 0) 421 return; 422 423 dprintf("object %4llu, txg %llu, pass %d, %c, count %lu, space %llx\n", 424 smo->smo_object, dmu_tx_get_txg(tx), spa_sync_pass(spa), 425 maptype == SM_ALLOC ? 'A' : 'F', avl_numnodes(&sm->sm_root), 426 sm->sm_space); 427 428 if (maptype == SM_ALLOC) 429 smo->smo_alloc += sm->sm_space; 430 else 431 smo->smo_alloc -= sm->sm_space; 432 433 bufsize = (8 + avl_numnodes(&sm->sm_root)) * sizeof (uint64_t); 434 bufsize = MIN(bufsize, 1ULL << SPACE_MAP_BLOCKSHIFT); 435 entry_map = zio_buf_alloc(bufsize); 436 entry_map_end = entry_map + (bufsize / sizeof (uint64_t)); 437 entry = entry_map; 438 439 *entry++ = SM_DEBUG_ENCODE(1) | 440 SM_DEBUG_ACTION_ENCODE(maptype) | 441 SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) | 442 SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx)); 443 444 while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) { 445 size = ss->ss_end - ss->ss_start; 446 start = (ss->ss_start - sm->sm_start) >> sm->sm_shift; 447 448 sm->sm_space -= size; 449 size >>= sm->sm_shift; 450 451 while (size) { 452 run_len = MIN(size, SM_RUN_MAX); 453 454 if (entry == entry_map_end) { 455 mutex_exit(sm->sm_lock); 456 dmu_write(os, smo->smo_object, smo->smo_objsize, 457 bufsize, entry_map, tx); 458 mutex_enter(sm->sm_lock); 459 smo->smo_objsize += bufsize; 460 entry = entry_map; 461 } 462 463 *entry++ = SM_OFFSET_ENCODE(start) | 464 SM_TYPE_ENCODE(maptype) | 465 SM_RUN_ENCODE(run_len); 466 467 start += run_len; 468 size -= run_len; 469 } 470 kmem_free(ss, sizeof (*ss)); 471 } 472 473 if (entry != entry_map) { 474 size = (entry - entry_map) * sizeof (uint64_t); 475 mutex_exit(sm->sm_lock); 476 dmu_write(os, smo->smo_object, smo->smo_objsize, 477 size, entry_map, tx); 478 mutex_enter(sm->sm_lock); 479 smo->smo_objsize += size; 480 } 481 482 zio_buf_free(entry_map, bufsize); 483 484 VERIFY3U(sm->sm_space, ==, 0); 485 } 486 487 void 488 space_map_truncate(space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx) 489 { 490 VERIFY(dmu_free_range(os, smo->smo_object, 0, -1ULL, tx) == 0); 491 492 smo->smo_objsize = 0; 493 smo->smo_alloc = 0; 494 } 495 496 /* 497 * Space map reference trees. 498 * 499 * A space map is a collection of integers. Every integer is either 500 * in the map, or it's not. A space map reference tree generalizes 501 * the idea: it allows its members to have arbitrary reference counts, 502 * as opposed to the implicit reference count of 0 or 1 in a space map. 503 * This representation comes in handy when computing the union or 504 * intersection of multiple space maps. For example, the union of 505 * N space maps is the subset of the reference tree with refcnt >= 1. 506 * The intersection of N space maps is the subset with refcnt >= N. 507 * 508 * [It's very much like a Fourier transform. Unions and intersections 509 * are hard to perform in the 'space map domain', so we convert the maps 510 * into the 'reference count domain', where it's trivial, then invert.] 511 * 512 * vdev_dtl_reassess() uses computations of this form to determine 513 * DTL_MISSING and DTL_OUTAGE for interior vdevs -- e.g. a RAID-Z vdev 514 * has an outage wherever refcnt >= vdev_nparity + 1, and a mirror vdev 515 * has an outage wherever refcnt >= vdev_children. 516 */ 517 static int 518 space_map_ref_compare(const void *x1, const void *x2) 519 { 520 const space_ref_t *sr1 = x1; 521 const space_ref_t *sr2 = x2; 522 523 if (sr1->sr_offset < sr2->sr_offset) 524 return (-1); 525 if (sr1->sr_offset > sr2->sr_offset) 526 return (1); 527 528 if (sr1 < sr2) 529 return (-1); 530 if (sr1 > sr2) 531 return (1); 532 533 return (0); 534 } 535 536 void 537 space_map_ref_create(avl_tree_t *t) 538 { 539 avl_create(t, space_map_ref_compare, 540 sizeof (space_ref_t), offsetof(space_ref_t, sr_node)); 541 } 542 543 void 544 space_map_ref_destroy(avl_tree_t *t) 545 { 546 space_ref_t *sr; 547 void *cookie = NULL; 548 549 while ((sr = avl_destroy_nodes(t, &cookie)) != NULL) 550 kmem_free(sr, sizeof (*sr)); 551 552 avl_destroy(t); 553 } 554 555 static void 556 space_map_ref_add_node(avl_tree_t *t, uint64_t offset, int64_t refcnt) 557 { 558 space_ref_t *sr; 559 560 sr = kmem_alloc(sizeof (*sr), KM_SLEEP); 561 sr->sr_offset = offset; 562 sr->sr_refcnt = refcnt; 563 564 avl_add(t, sr); 565 } 566 567 void 568 space_map_ref_add_seg(avl_tree_t *t, uint64_t start, uint64_t end, 569 int64_t refcnt) 570 { 571 space_map_ref_add_node(t, start, refcnt); 572 space_map_ref_add_node(t, end, -refcnt); 573 } 574 575 /* 576 * Convert (or add) a space map into a reference tree. 577 */ 578 void 579 space_map_ref_add_map(avl_tree_t *t, space_map_t *sm, int64_t refcnt) 580 { 581 space_seg_t *ss; 582 583 ASSERT(MUTEX_HELD(sm->sm_lock)); 584 585 for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss)) 586 space_map_ref_add_seg(t, ss->ss_start, ss->ss_end, refcnt); 587 } 588 589 /* 590 * Convert a reference tree into a space map. The space map will contain 591 * all members of the reference tree for which refcnt >= minref. 592 */ 593 void 594 space_map_ref_generate_map(avl_tree_t *t, space_map_t *sm, int64_t minref) 595 { 596 uint64_t start = -1ULL; 597 int64_t refcnt = 0; 598 space_ref_t *sr; 599 600 ASSERT(MUTEX_HELD(sm->sm_lock)); 601 602 space_map_vacate(sm, NULL, NULL); 603 604 for (sr = avl_first(t); sr != NULL; sr = AVL_NEXT(t, sr)) { 605 refcnt += sr->sr_refcnt; 606 if (refcnt >= minref) { 607 if (start == -1ULL) { 608 start = sr->sr_offset; 609 } 610 } else { 611 if (start != -1ULL) { 612 uint64_t end = sr->sr_offset; 613 ASSERT(start <= end); 614 if (end > start) 615 space_map_add(sm, start, end - start); 616 start = -1ULL; 617 } 618 } 619 } 620 ASSERT(refcnt == 0); 621 ASSERT(start == -1ULL); 622 } 623