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 2008 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 ss_after->ss_start = ss_before->ss_start; 120 kmem_free(ss_before, sizeof (*ss_before)); 121 } else if (merge_before) { 122 ss_before->ss_end = end; 123 } else if (merge_after) { 124 ss_after->ss_start = start; 125 } else { 126 ss = kmem_alloc(sizeof (*ss), KM_SLEEP); 127 ss->ss_start = start; 128 ss->ss_end = end; 129 avl_insert(&sm->sm_root, ss, where); 130 } 131 132 sm->sm_space += size; 133 } 134 135 void 136 space_map_remove(space_map_t *sm, uint64_t start, uint64_t size) 137 { 138 avl_index_t where; 139 space_seg_t ssearch, *ss, *newseg; 140 uint64_t end = start + size; 141 int left_over, right_over; 142 143 ASSERT(MUTEX_HELD(sm->sm_lock)); 144 VERIFY(size != 0); 145 VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0); 146 VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0); 147 148 ssearch.ss_start = start; 149 ssearch.ss_end = end; 150 ss = avl_find(&sm->sm_root, &ssearch, &where); 151 152 /* Make sure we completely overlap with someone */ 153 if (ss == NULL) { 154 zfs_panic_recover("zfs: freeing free segment " 155 "(offset=%llu size=%llu)", 156 (longlong_t)start, (longlong_t)size); 157 return; 158 } 159 VERIFY3U(ss->ss_start, <=, start); 160 VERIFY3U(ss->ss_end, >=, end); 161 VERIFY(sm->sm_space - size <= sm->sm_size); 162 163 left_over = (ss->ss_start != start); 164 right_over = (ss->ss_end != end); 165 166 if (left_over && right_over) { 167 newseg = kmem_alloc(sizeof (*newseg), KM_SLEEP); 168 newseg->ss_start = end; 169 newseg->ss_end = ss->ss_end; 170 ss->ss_end = start; 171 avl_insert_here(&sm->sm_root, newseg, ss, AVL_AFTER); 172 } else if (left_over) { 173 ss->ss_end = start; 174 } else if (right_over) { 175 ss->ss_start = end; 176 } else { 177 avl_remove(&sm->sm_root, ss); 178 kmem_free(ss, sizeof (*ss)); 179 } 180 181 sm->sm_space -= size; 182 } 183 184 boolean_t 185 space_map_contains(space_map_t *sm, uint64_t start, uint64_t size) 186 { 187 avl_index_t where; 188 space_seg_t ssearch, *ss; 189 uint64_t end = start + size; 190 191 ASSERT(MUTEX_HELD(sm->sm_lock)); 192 VERIFY(size != 0); 193 VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0); 194 VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0); 195 196 ssearch.ss_start = start; 197 ssearch.ss_end = end; 198 ss = avl_find(&sm->sm_root, &ssearch, &where); 199 200 return (ss != NULL && ss->ss_start <= start && ss->ss_end >= end); 201 } 202 203 void 204 space_map_vacate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest) 205 { 206 space_seg_t *ss; 207 void *cookie = NULL; 208 209 ASSERT(MUTEX_HELD(sm->sm_lock)); 210 211 while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) { 212 if (func != NULL) 213 func(mdest, ss->ss_start, ss->ss_end - ss->ss_start); 214 kmem_free(ss, sizeof (*ss)); 215 } 216 sm->sm_space = 0; 217 } 218 219 void 220 space_map_walk(space_map_t *sm, space_map_func_t *func, space_map_t *mdest) 221 { 222 space_seg_t *ss; 223 224 ASSERT(MUTEX_HELD(sm->sm_lock)); 225 226 for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss)) 227 func(mdest, ss->ss_start, ss->ss_end - ss->ss_start); 228 } 229 230 /* 231 * Wait for any in-progress space_map_load() to complete. 232 */ 233 void 234 space_map_load_wait(space_map_t *sm) 235 { 236 ASSERT(MUTEX_HELD(sm->sm_lock)); 237 238 while (sm->sm_loading) 239 cv_wait(&sm->sm_load_cv, sm->sm_lock); 240 } 241 242 /* 243 * Note: space_map_load() will drop sm_lock across dmu_read() calls. 244 * The caller must be OK with this. 245 */ 246 int 247 space_map_load(space_map_t *sm, space_map_ops_t *ops, uint8_t maptype, 248 space_map_obj_t *smo, objset_t *os) 249 { 250 uint64_t *entry, *entry_map, *entry_map_end; 251 uint64_t bufsize, size, offset, end, space; 252 uint64_t mapstart = sm->sm_start; 253 int error = 0; 254 255 ASSERT(MUTEX_HELD(sm->sm_lock)); 256 257 space_map_load_wait(sm); 258 259 if (sm->sm_loaded) 260 return (0); 261 262 sm->sm_loading = B_TRUE; 263 end = smo->smo_objsize; 264 space = smo->smo_alloc; 265 266 ASSERT(sm->sm_ops == NULL); 267 VERIFY3U(sm->sm_space, ==, 0); 268 269 if (maptype == SM_FREE) { 270 space_map_add(sm, sm->sm_start, sm->sm_size); 271 space = sm->sm_size - space; 272 } 273 274 bufsize = 1ULL << SPACE_MAP_BLOCKSHIFT; 275 entry_map = zio_buf_alloc(bufsize); 276 277 mutex_exit(sm->sm_lock); 278 if (end > bufsize) 279 dmu_prefetch(os, smo->smo_object, bufsize, end - bufsize); 280 mutex_enter(sm->sm_lock); 281 282 for (offset = 0; offset < end; offset += bufsize) { 283 size = MIN(end - offset, bufsize); 284 VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0); 285 VERIFY(size != 0); 286 287 dprintf("object=%llu offset=%llx size=%llx\n", 288 smo->smo_object, offset, size); 289 290 mutex_exit(sm->sm_lock); 291 error = dmu_read(os, smo->smo_object, offset, size, entry_map); 292 mutex_enter(sm->sm_lock); 293 if (error != 0) 294 break; 295 296 entry_map_end = entry_map + (size / sizeof (uint64_t)); 297 for (entry = entry_map; entry < entry_map_end; entry++) { 298 uint64_t e = *entry; 299 300 if (SM_DEBUG_DECODE(e)) /* Skip debug entries */ 301 continue; 302 303 (SM_TYPE_DECODE(e) == maptype ? 304 space_map_add : space_map_remove)(sm, 305 (SM_OFFSET_DECODE(e) << sm->sm_shift) + mapstart, 306 SM_RUN_DECODE(e) << sm->sm_shift); 307 } 308 } 309 310 if (error == 0) { 311 VERIFY3U(sm->sm_space, ==, space); 312 313 sm->sm_loaded = B_TRUE; 314 sm->sm_ops = ops; 315 if (ops != NULL) 316 ops->smop_load(sm); 317 } else { 318 space_map_vacate(sm, NULL, NULL); 319 } 320 321 zio_buf_free(entry_map, bufsize); 322 323 sm->sm_loading = B_FALSE; 324 325 cv_broadcast(&sm->sm_load_cv); 326 327 return (error); 328 } 329 330 void 331 space_map_unload(space_map_t *sm) 332 { 333 ASSERT(MUTEX_HELD(sm->sm_lock)); 334 335 if (sm->sm_loaded && sm->sm_ops != NULL) 336 sm->sm_ops->smop_unload(sm); 337 338 sm->sm_loaded = B_FALSE; 339 sm->sm_ops = NULL; 340 341 space_map_vacate(sm, NULL, NULL); 342 } 343 344 uint64_t 345 space_map_alloc(space_map_t *sm, uint64_t size) 346 { 347 uint64_t start; 348 349 start = sm->sm_ops->smop_alloc(sm, size); 350 if (start != -1ULL) 351 space_map_remove(sm, start, size); 352 return (start); 353 } 354 355 void 356 space_map_claim(space_map_t *sm, uint64_t start, uint64_t size) 357 { 358 sm->sm_ops->smop_claim(sm, start, size); 359 space_map_remove(sm, start, size); 360 } 361 362 void 363 space_map_free(space_map_t *sm, uint64_t start, uint64_t size) 364 { 365 space_map_add(sm, start, size); 366 sm->sm_ops->smop_free(sm, start, size); 367 } 368 369 /* 370 * Note: space_map_sync() will drop sm_lock across dmu_write() calls. 371 */ 372 void 373 space_map_sync(space_map_t *sm, uint8_t maptype, 374 space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx) 375 { 376 spa_t *spa = dmu_objset_spa(os); 377 void *cookie = NULL; 378 space_seg_t *ss; 379 uint64_t bufsize, start, size, run_len; 380 uint64_t *entry, *entry_map, *entry_map_end; 381 382 ASSERT(MUTEX_HELD(sm->sm_lock)); 383 384 if (sm->sm_space == 0) 385 return; 386 387 dprintf("object %4llu, txg %llu, pass %d, %c, count %lu, space %llx\n", 388 smo->smo_object, dmu_tx_get_txg(tx), spa_sync_pass(spa), 389 maptype == SM_ALLOC ? 'A' : 'F', avl_numnodes(&sm->sm_root), 390 sm->sm_space); 391 392 if (maptype == SM_ALLOC) 393 smo->smo_alloc += sm->sm_space; 394 else 395 smo->smo_alloc -= sm->sm_space; 396 397 bufsize = (8 + avl_numnodes(&sm->sm_root)) * sizeof (uint64_t); 398 bufsize = MIN(bufsize, 1ULL << SPACE_MAP_BLOCKSHIFT); 399 entry_map = zio_buf_alloc(bufsize); 400 entry_map_end = entry_map + (bufsize / sizeof (uint64_t)); 401 entry = entry_map; 402 403 *entry++ = SM_DEBUG_ENCODE(1) | 404 SM_DEBUG_ACTION_ENCODE(maptype) | 405 SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) | 406 SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx)); 407 408 while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) { 409 size = ss->ss_end - ss->ss_start; 410 start = (ss->ss_start - sm->sm_start) >> sm->sm_shift; 411 412 sm->sm_space -= size; 413 size >>= sm->sm_shift; 414 415 while (size) { 416 run_len = MIN(size, SM_RUN_MAX); 417 418 if (entry == entry_map_end) { 419 mutex_exit(sm->sm_lock); 420 dmu_write(os, smo->smo_object, smo->smo_objsize, 421 bufsize, entry_map, tx); 422 mutex_enter(sm->sm_lock); 423 smo->smo_objsize += bufsize; 424 entry = entry_map; 425 } 426 427 *entry++ = SM_OFFSET_ENCODE(start) | 428 SM_TYPE_ENCODE(maptype) | 429 SM_RUN_ENCODE(run_len); 430 431 start += run_len; 432 size -= run_len; 433 } 434 kmem_free(ss, sizeof (*ss)); 435 } 436 437 if (entry != entry_map) { 438 size = (entry - entry_map) * sizeof (uint64_t); 439 mutex_exit(sm->sm_lock); 440 dmu_write(os, smo->smo_object, smo->smo_objsize, 441 size, entry_map, tx); 442 mutex_enter(sm->sm_lock); 443 smo->smo_objsize += size; 444 } 445 446 zio_buf_free(entry_map, bufsize); 447 448 VERIFY3U(sm->sm_space, ==, 0); 449 } 450 451 void 452 space_map_truncate(space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx) 453 { 454 VERIFY(dmu_free_range(os, smo->smo_object, 0, -1ULL, tx) == 0); 455 456 smo->smo_objsize = 0; 457 smo->smo_alloc = 0; 458 } 459 460 /* 461 * Space map reference trees. 462 * 463 * A space map is a collection of integers. Every integer is either 464 * in the map, or it's not. A space map reference tree generalizes 465 * the idea: it allows its members to have arbitrary reference counts, 466 * as opposed to the implicit reference count of 0 or 1 in a space map. 467 * This representation comes in handy when computing the union or 468 * intersection of multiple space maps. For example, the union of 469 * N space maps is the subset of the reference tree with refcnt >= 1. 470 * The intersection of N space maps is the subset with refcnt >= N. 471 * 472 * [It's very much like a Fourier transform. Unions and intersections 473 * are hard to perform in the 'space map domain', so we convert the maps 474 * into the 'reference count domain', where it's trivial, then invert.] 475 * 476 * vdev_dtl_reassess() uses computations of this form to determine 477 * DTL_MISSING and DTL_OUTAGE for interior vdevs -- e.g. a RAID-Z vdev 478 * has an outage wherever refcnt >= vdev_nparity + 1, and a mirror vdev 479 * has an outage wherever refcnt >= vdev_children. 480 */ 481 static int 482 space_map_ref_compare(const void *x1, const void *x2) 483 { 484 const space_ref_t *sr1 = x1; 485 const space_ref_t *sr2 = x2; 486 487 if (sr1->sr_offset < sr2->sr_offset) 488 return (-1); 489 if (sr1->sr_offset > sr2->sr_offset) 490 return (1); 491 492 if (sr1 < sr2) 493 return (-1); 494 if (sr1 > sr2) 495 return (1); 496 497 return (0); 498 } 499 500 void 501 space_map_ref_create(avl_tree_t *t) 502 { 503 avl_create(t, space_map_ref_compare, 504 sizeof (space_ref_t), offsetof(space_ref_t, sr_node)); 505 } 506 507 void 508 space_map_ref_destroy(avl_tree_t *t) 509 { 510 space_ref_t *sr; 511 void *cookie = NULL; 512 513 while ((sr = avl_destroy_nodes(t, &cookie)) != NULL) 514 kmem_free(sr, sizeof (*sr)); 515 516 avl_destroy(t); 517 } 518 519 static void 520 space_map_ref_add_node(avl_tree_t *t, uint64_t offset, int64_t refcnt) 521 { 522 space_ref_t *sr; 523 524 sr = kmem_alloc(sizeof (*sr), KM_SLEEP); 525 sr->sr_offset = offset; 526 sr->sr_refcnt = refcnt; 527 528 avl_add(t, sr); 529 } 530 531 void 532 space_map_ref_add_seg(avl_tree_t *t, uint64_t start, uint64_t end, 533 int64_t refcnt) 534 { 535 space_map_ref_add_node(t, start, refcnt); 536 space_map_ref_add_node(t, end, -refcnt); 537 } 538 539 /* 540 * Convert (or add) a space map into a reference tree. 541 */ 542 void 543 space_map_ref_add_map(avl_tree_t *t, space_map_t *sm, int64_t refcnt) 544 { 545 space_seg_t *ss; 546 547 ASSERT(MUTEX_HELD(sm->sm_lock)); 548 549 for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss)) 550 space_map_ref_add_seg(t, ss->ss_start, ss->ss_end, refcnt); 551 } 552 553 /* 554 * Convert a reference tree into a space map. The space map will contain 555 * all members of the reference tree for which refcnt >= minref. 556 */ 557 void 558 space_map_ref_generate_map(avl_tree_t *t, space_map_t *sm, int64_t minref) 559 { 560 uint64_t start = -1ULL; 561 int64_t refcnt = 0; 562 space_ref_t *sr; 563 564 ASSERT(MUTEX_HELD(sm->sm_lock)); 565 566 space_map_vacate(sm, NULL, NULL); 567 568 for (sr = avl_first(t); sr != NULL; sr = AVL_NEXT(t, sr)) { 569 refcnt += sr->sr_refcnt; 570 if (refcnt >= minref) { 571 if (start == -1ULL) { 572 start = sr->sr_offset; 573 } 574 } else { 575 if (start != -1ULL) { 576 uint64_t end = sr->sr_offset; 577 ASSERT(start <= end); 578 if (end > start) 579 space_map_add(sm, start, end - start); 580 start = -1ULL; 581 } 582 } 583 } 584 ASSERT(refcnt == 0); 585 ASSERT(start == -1ULL); 586 } 587