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 }