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 * Copyright (c) 2013 by Delphix. All rights reserved.
27 */
28
29 #include <sys/zfs_context.h>
30 #include <sys/spa.h>
31 #include <sys/dmu.h>
32 #include <sys/dmu_tx.h>
33 #include <sys/dnode.h>
34 #include <sys/dsl_pool.h>
35 #include <sys/zio.h>
36 #include <sys/space_map.h>
37 #include <sys/refcount.h>
38 #include <sys/zfeature.h>
39
40 /*
41 * This value controls how the space map's block size is allowed to grow.
42 * If the value is set to the same size as SPACE_MAP_INITIAL_BLOCKSIZE then
43 * the space map block size will remain fixed. Setting this value to something
44 * greater than SPACE_MAP_INITIAL_BLOCKSIZE will allow the space map to
45 * increase its block size as needed. To maintain backwards compatibilty the
46 * space map's block size must be a power of 2 and SPACE_MAP_INITIAL_BLOCKSIZE
47 * or larger.
48 */
49 int space_map_max_blksz = (1 << 12);
50
51 /*
52 * Load the space map disk into the specified range tree. Segments of maptype
53 * are added to the range tree, other segment types are removed.
54 *
55 * Note: space_map_load() will drop sm_lock across dmu_read() calls.
56 * The caller must be OK with this.
57 */
58 int
59 space_map_load(space_map_t *sm, range_tree_t *rt, maptype_t maptype)
60 {
61 uint64_t *entry, *entry_map, *entry_map_end;
62 uint64_t bufsize, size, offset, end, space;
63 int error = 0;
64
65 ASSERT(MUTEX_HELD(sm->sm_lock));
66
67 end = space_map_length(sm);
68 space = space_map_allocated(sm);
69
70 VERIFY0(range_tree_space(rt));
71
72 if (maptype == SM_FREE) {
73 range_tree_add(rt, sm->sm_start, sm->sm_size);
74 space = sm->sm_size - space;
75 }
76
77 bufsize = MAX(sm->sm_blksz, SPA_MINBLOCKSIZE);
78 entry_map = zio_buf_alloc(bufsize);
79
80 mutex_exit(sm->sm_lock);
81 if (end > bufsize) {
82 dmu_prefetch(sm->sm_os, space_map_object(sm), bufsize,
83 end - bufsize);
84 }
85 mutex_enter(sm->sm_lock);
86
87 for (offset = 0; offset < end; offset += bufsize) {
88 size = MIN(end - offset, bufsize);
89 VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0);
90 VERIFY(size != 0);
91 ASSERT3U(sm->sm_blksz, !=, 0);
92
93 dprintf("object=%llu offset=%llx size=%llx\n",
94 space_map_object(sm), offset, size);
95
96 mutex_exit(sm->sm_lock);
97 error = dmu_read(sm->sm_os, space_map_object(sm), offset, size,
98 entry_map, DMU_READ_PREFETCH);
99 mutex_enter(sm->sm_lock);
100 if (error != 0)
101 break;
102
103 entry_map_end = entry_map + (size / sizeof (uint64_t));
104 for (entry = entry_map; entry < entry_map_end; entry++) {
105 uint64_t e = *entry;
106 uint64_t offset, size;
107
108 if (SM_DEBUG_DECODE(e)) /* Skip debug entries */
109 continue;
110
111 offset = (SM_OFFSET_DECODE(e) << sm->sm_shift) +
112 sm->sm_start;
113 size = SM_RUN_DECODE(e) << sm->sm_shift;
114
115 VERIFY0(P2PHASE(offset, 1ULL << sm->sm_shift));
116 VERIFY0(P2PHASE(size, 1ULL << sm->sm_shift));
117 VERIFY3U(offset, >=, sm->sm_start);
118 VERIFY3U(offset + size, <=, sm->sm_start + sm->sm_size);
119 if (SM_TYPE_DECODE(e) == maptype) {
120 VERIFY3U(range_tree_space(rt) + size, <=,
121 sm->sm_size);
122 range_tree_add(rt, offset, size);
123 } else {
124 range_tree_remove(rt, offset, size);
125 }
126 }
127 }
128
129 if (error == 0)
130 VERIFY3U(range_tree_space(rt), ==, space);
131 else
132 range_tree_vacate(rt, NULL, NULL);
133
134 zio_buf_free(entry_map, bufsize);
135 return (error);
136 }
137
138 void
139 space_map_histogram_clear(space_map_t *sm)
140 {
141 if (sm->sm_dbuf->db_size != sizeof (space_map_phys_t))
142 return;
143
144 bzero(sm->sm_phys->smp_histogram, sizeof (sm->sm_phys->smp_histogram));
145 }
146
147 boolean_t
148 space_map_histogram_verify(space_map_t *sm, range_tree_t *rt)
149 {
150 /*
151 * Verify that the in-core range tree does not have any
152 * ranges smaller than our sm_shift size.
153 */
154 for (int i = 0; i < sm->sm_shift; i++) {
155 if (rt->rt_histogram[i] != 0)
156 return (B_FALSE);
157 }
158 return (B_TRUE);
159 }
160
161 void
162 space_map_histogram_add(space_map_t *sm, range_tree_t *rt, dmu_tx_t *tx)
163 {
164 int idx = 0;
165
166 ASSERT(MUTEX_HELD(rt->rt_lock));
167 ASSERT(dmu_tx_is_syncing(tx));
168 VERIFY3U(space_map_object(sm), !=, 0);
169
170 if (sm->sm_dbuf->db_size != sizeof (space_map_phys_t))
171 return;
172
173 dmu_buf_will_dirty(sm->sm_dbuf, tx);
174
175 ASSERT(space_map_histogram_verify(sm, rt));
176
177 /*
178 * Transfer the content of the range tree histogram to the space
179 * map histogram. The space map histogram contains 32 buckets ranging
180 * between 2^sm_shift to 2^(32+sm_shift-1). The range tree,
181 * however, can represent ranges from 2^0 to 2^63. Since the space
182 * map only cares about allocatable blocks (minimum of sm_shift) we
183 * can safely ignore all ranges in the range tree smaller than sm_shift.
184 */
185 for (int i = sm->sm_shift; i < RANGE_TREE_HISTOGRAM_SIZE; i++) {
186
187 /*
188 * Since the largest histogram bucket in the space map is
189 * 2^(32+sm_shift-1), we need to normalize the values in
190 * the range tree for any bucket larger than that size. For
191 * example given an sm_shift of 9, ranges larger than 2^40
192 * would get normalized as if they were 1TB ranges. Assume
193 * the range tree had a count of 5 in the 2^44 (16TB) bucket,
194 * the calculation below would normalize this to 5 * 2^4 (16).
195 */
196 ASSERT3U(i, >=, idx + sm->sm_shift);
197 sm->sm_phys->smp_histogram[idx] +=
198 rt->rt_histogram[i] << (i - idx - sm->sm_shift);
199
200 /*
201 * Increment the space map's index as long as we haven't
202 * reached the maximum bucket size. Accumulate all ranges
203 * larger than the max bucket size into the last bucket.
204 */
205 if (idx < SPACE_MAP_HISTOGRAM_SIZE(sm) - 1) {
206 ASSERT3U(idx + sm->sm_shift, ==, i);
207 idx++;
208 ASSERT3U(idx, <, SPACE_MAP_HISTOGRAM_SIZE(sm));
209 }
210 }
211 }
212
213 uint64_t
214 space_map_entries(space_map_t *sm, range_tree_t *rt)
215 {
216 avl_tree_t *t = &rt->rt_root;
217 range_seg_t *rs;
218 uint64_t size, entries;
219
220 /*
221 * All space_maps always have a debug entry so account for it here.
222 */
223 entries = 1;
224
225 /*
226 * Traverse the range tree and calculate the number of space map
227 * entries that would be required to write out the range tree.
228 */
229 for (rs = avl_first(t); rs != NULL; rs = AVL_NEXT(t, rs)) {
230 size = (rs->rs_end - rs->rs_start) >> sm->sm_shift;
231 entries += howmany(size, SM_RUN_MAX);
232 }
233 return (entries);
234 }
235
236 void
237 space_map_set_blocksize(space_map_t *sm, uint64_t size, dmu_tx_t *tx)
238 {
239 uint32_t blksz;
240 u_longlong_t blocks;
241
242 ASSERT3U(sm->sm_blksz, !=, 0);
243 ASSERT3U(space_map_object(sm), !=, 0);
244 ASSERT(sm->sm_dbuf != NULL);
245 VERIFY(ISP2(space_map_max_blksz));
246
247 if (sm->sm_blksz >= space_map_max_blksz)
248 return;
249
250 /*
251 * The object contains more than one block so we can't adjust
252 * its size.
253 */
254 if (sm->sm_phys->smp_objsize > sm->sm_blksz)
255 return;
256
257 if (size > sm->sm_blksz) {
258 uint64_t newsz;
259
260 /*
261 * Older software versions treat space map blocks as fixed
262 * entities. The DMU is capable of handling different block
263 * sizes making it possible for us to increase the
264 * block size and maintain backwards compatibility. The
265 * caveat is that the new block sizes must be a
266 * power of 2 so that old software can append to the file,
267 * adding more blocks. The block size can grow until it
268 * reaches space_map_max_blksz.
269 */
270 newsz = ISP2(size) ? size : 1ULL << highbit(size);
271 if (newsz > space_map_max_blksz)
272 newsz = space_map_max_blksz;
273
274 VERIFY0(dmu_object_set_blocksize(sm->sm_os,
275 space_map_object(sm), newsz, 0, tx));
276 dmu_object_size_from_db(sm->sm_dbuf, &blksz, &blocks);
277
278 zfs_dbgmsg("txg %llu, spa %s, increasing blksz from %d to %d",
279 dmu_tx_get_txg(tx), spa_name(dmu_objset_spa(sm->sm_os)),
280 sm->sm_blksz, blksz);
281
282 VERIFY3U(newsz, ==, blksz);
283 VERIFY3U(sm->sm_blksz, <, blksz);
284 sm->sm_blksz = blksz;
285 }
286 }
287
288 /*
289 * Note: space_map_write() will drop sm_lock across dmu_write() calls.
290 */
291 void
292 space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
293 dmu_tx_t *tx)
294 {
295 objset_t *os = sm->sm_os;
296 spa_t *spa = dmu_objset_spa(os);
297 avl_tree_t *t = &rt->rt_root;
298 range_seg_t *rs;
299 uint64_t size, total, rt_space, nodes;
300 uint64_t *entry, *entry_map, *entry_map_end;
301 uint64_t newsz, expected_entries, actual_entries = 1;
302
303 ASSERT(MUTEX_HELD(rt->rt_lock));
304 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
305 VERIFY3U(space_map_object(sm), !=, 0);
306 dmu_buf_will_dirty(sm->sm_dbuf, tx);
307
308 /*
309 * This field is no longer necessary since the in-core space map
310 * now contains the object number but is maintained for backwards
311 * compatibility.
312 */
313 sm->sm_phys->smp_object = sm->sm_object;
314
315 if (range_tree_space(rt) == 0) {
316 VERIFY3U(sm->sm_object, ==, sm->sm_phys->smp_object);
317 return;
318 }
319
320 if (maptype == SM_ALLOC)
321 sm->sm_phys->smp_alloc += range_tree_space(rt);
322 else
323 sm->sm_phys->smp_alloc -= range_tree_space(rt);
324
325 expected_entries = space_map_entries(sm, rt);
326
327 /*
328 * Calculate the new size for the space map on-disk and see if
329 * we can grow the block size to accommodate the new size.
330 */
331 newsz = sm->sm_phys->smp_objsize + expected_entries * sizeof (uint64_t);
332 space_map_set_blocksize(sm, newsz, tx);
333
334 entry_map = zio_buf_alloc(sm->sm_blksz);
335 entry_map_end = entry_map + (sm->sm_blksz / sizeof (uint64_t));
336 entry = entry_map;
337
338 *entry++ = SM_DEBUG_ENCODE(1) |
339 SM_DEBUG_ACTION_ENCODE(maptype) |
340 SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) |
341 SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx));
342
343 total = 0;
344 nodes = avl_numnodes(&rt->rt_root);
345 rt_space = range_tree_space(rt);
346 for (rs = avl_first(t); rs != NULL; rs = AVL_NEXT(t, rs)) {
347 uint64_t start;
348
349 size = (rs->rs_end - rs->rs_start) >> sm->sm_shift;
350 start = (rs->rs_start - sm->sm_start) >> sm->sm_shift;
351
352 total += size << sm->sm_shift;
353
354 while (size != 0) {
355 uint64_t run_len;
356
357 run_len = MIN(size, SM_RUN_MAX);
358
359 if (entry == entry_map_end) {
360 mutex_exit(rt->rt_lock);
361 dmu_write(os, space_map_object(sm),
362 sm->sm_phys->smp_objsize, sm->sm_blksz,
363 entry_map, tx);
364 mutex_enter(rt->rt_lock);
365 sm->sm_phys->smp_objsize += sm->sm_blksz;
366 entry = entry_map;
367 }
368
369 *entry++ = SM_OFFSET_ENCODE(start) |
370 SM_TYPE_ENCODE(maptype) |
371 SM_RUN_ENCODE(run_len);
372
373 start += run_len;
374 size -= run_len;
375 actual_entries++;
376 }
377 }
378
379 if (entry != entry_map) {
380 size = (entry - entry_map) * sizeof (uint64_t);
381 mutex_exit(rt->rt_lock);
382 dmu_write(os, space_map_object(sm), sm->sm_phys->smp_objsize,
383 size, entry_map, tx);
384 mutex_enter(rt->rt_lock);
385 sm->sm_phys->smp_objsize += size;
386 }
387 ASSERT3U(expected_entries, ==, actual_entries);
388
389 /*
390 * Ensure that the space_map's accounting wasn't changed
391 * while we were in the middle of writing it out.
392 */
393 VERIFY3U(nodes, ==, avl_numnodes(&rt->rt_root));
394 VERIFY3U(range_tree_space(rt), ==, rt_space);
395 VERIFY3U(range_tree_space(rt), ==, total);
396
397 zio_buf_free(entry_map, sm->sm_blksz);
398 }
399
400 static int
401 space_map_open_impl(space_map_t *sm)
402 {
403 int error;
404 u_longlong_t blocks;
405
406 error = dmu_bonus_hold(sm->sm_os, sm->sm_object, sm, &sm->sm_dbuf);
407 if (error)
408 return (error);
409
410 dmu_object_size_from_db(sm->sm_dbuf, &sm->sm_blksz, &blocks);
411 sm->sm_phys = sm->sm_dbuf->db_data;
412 return (0);
413 }
414
415 int
416 space_map_open(space_map_t **smp, objset_t *os, uint64_t object,
417 uint64_t start, uint64_t size, uint8_t shift, kmutex_t *lp)
418 {
419 space_map_t *sm;
420 int error;
421
422 ASSERT(*smp == NULL);
423 ASSERT(os != NULL);
424 ASSERT(object != 0);
425
426 sm = kmem_zalloc(sizeof (space_map_t), KM_SLEEP);
427
428 sm->sm_start = start;
429 sm->sm_size = size;
430 sm->sm_shift = shift;
431 sm->sm_lock = lp;
432 sm->sm_os = os;
433 sm->sm_object = object;
434
435 error = space_map_open_impl(sm);
436 if (error != 0) {
437 space_map_close(sm);
438 return (error);
439 }
440
441 *smp = sm;
442
443 return (0);
444 }
445
446 void
447 space_map_close(space_map_t *sm)
448 {
449 if (sm == NULL)
450 return;
451
452 if (sm->sm_dbuf != NULL)
453 dmu_buf_rele(sm->sm_dbuf, sm);
454 sm->sm_dbuf = NULL;
455 sm->sm_phys = NULL;
456
457 kmem_free(sm, sizeof (*sm));
458 }
459
460 static void
461 space_map_reallocate(space_map_t *sm, dmu_tx_t *tx)
462 {
463 ASSERT(dmu_tx_is_syncing(tx));
464
465 space_map_free(sm, tx);
466 dmu_buf_rele(sm->sm_dbuf, sm);
467
468 sm->sm_object = space_map_alloc(sm->sm_os, tx);
469 VERIFY0(space_map_open_impl(sm));
470 }
471
472 void
473 space_map_truncate(space_map_t *sm, dmu_tx_t *tx)
474 {
475 objset_t *os = sm->sm_os;
476 spa_t *spa = dmu_objset_spa(os);
477 dmu_object_info_t doi;
478 int bonuslen;
479
480 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
481 ASSERT(dmu_tx_is_syncing(tx));
482
483 VERIFY0(dmu_free_range(os, space_map_object(sm), 0, -1ULL, tx));
484 dmu_object_info_from_db(sm->sm_dbuf, &doi);
485
486 if (spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM)) {
487 bonuslen = sizeof (space_map_phys_t);
488 ASSERT3U(bonuslen, <=, dmu_bonus_max());
489 } else {
490 bonuslen = SPACE_MAP_SIZE_V0;
491 }
492
493 if (bonuslen != doi.doi_bonus_size ||
494 doi.doi_data_block_size != SPACE_MAP_INITIAL_BLOCKSIZE) {
495 zfs_dbgmsg("txg %llu, spa %s, reallocating: "
496 "old bonus %u, old blocksz %u", dmu_tx_get_txg(tx),
497 spa_name(spa), doi.doi_bonus_size, doi.doi_data_block_size);
498 space_map_reallocate(sm, tx);
499 VERIFY3U(sm->sm_blksz, ==, SPACE_MAP_INITIAL_BLOCKSIZE);
500 }
501
502 dmu_buf_will_dirty(sm->sm_dbuf, tx);
503 sm->sm_phys->smp_objsize = 0;
504 sm->sm_phys->smp_alloc = 0;
505 }
506
507 /*
508 * Update the in-core space_map allocation and length values.
509 */
510 void
511 space_map_update(space_map_t *sm)
512 {
513 if (sm == NULL)
514 return;
515
516 ASSERT(MUTEX_HELD(sm->sm_lock));
517
518 sm->sm_alloc = sm->sm_phys->smp_alloc;
519 sm->sm_length = sm->sm_phys->smp_objsize;
520 }
521
522 uint64_t
523 space_map_alloc(objset_t *os, dmu_tx_t *tx)
524 {
525 spa_t *spa = dmu_objset_spa(os);
526 uint64_t object;
527 int bonuslen;
528
529 if (spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM)) {
530 spa_feature_incr(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM, tx);
531 bonuslen = sizeof (space_map_phys_t);
532 ASSERT3U(bonuslen, <=, dmu_bonus_max());
533 } else {
534 bonuslen = SPACE_MAP_SIZE_V0;
535 }
536
537 object = dmu_object_alloc(os,
538 DMU_OT_SPACE_MAP, SPACE_MAP_INITIAL_BLOCKSIZE,
539 DMU_OT_SPACE_MAP_HEADER, bonuslen, tx);
540
541 return (object);
542 }
543
544 void
545 space_map_free(space_map_t *sm, dmu_tx_t *tx)
546 {
547 spa_t *spa;
548
549 if (sm == NULL)
550 return;
551
552 spa = dmu_objset_spa(sm->sm_os);
553 if (spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM)) {
554 dmu_object_info_t doi;
555
556 dmu_object_info_from_db(sm->sm_dbuf, &doi);
557 if (doi.doi_bonus_size != SPACE_MAP_SIZE_V0) {
558 VERIFY(spa_feature_is_active(spa,
559 SPA_FEATURE_SPACEMAP_HISTOGRAM));
560 spa_feature_decr(spa,
561 SPA_FEATURE_SPACEMAP_HISTOGRAM, tx);
562 }
563 }
564
565 VERIFY3U(dmu_object_free(sm->sm_os, space_map_object(sm), tx), ==, 0);
566 sm->sm_object = 0;
567 }
568
569 uint64_t
570 space_map_object(space_map_t *sm)
571 {
572 return (sm != NULL ? sm->sm_object : 0);
573 }
574
575 /*
576 * Returns the already synced, on-disk allocated space.
577 */
578 uint64_t
579 space_map_allocated(space_map_t *sm)
580 {
581 return (sm != NULL ? sm->sm_alloc : 0);
582 }
583
584 /*
585 * Returns the already synced, on-disk length;
586 */
587 uint64_t
588 space_map_length(space_map_t *sm)
589 {
590 return (sm != NULL ? sm->sm_length : 0);
591 }
592
593 /*
594 * Returns the allocated space that is currently syncing.
595 */
596 int64_t
597 space_map_alloc_delta(space_map_t *sm)
598 {
599 if (sm == NULL)
600 return (0);
601 ASSERT(sm->sm_dbuf != NULL);
602 return (sm->sm_phys->smp_alloc - space_map_allocated(sm));
603 }