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) 2012, 2014 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 * The data for a given space map can be kept on blocks of any size.
42 * Larger blocks entail fewer i/o operations, but they also cause the
43 * DMU to keep more data in-core, and also to waste more i/o bandwidth
44 * when only a few blocks have changed since the last transaction group.
45 */
46 int space_map_blksz = (1 << 12);
47
48 /*
49 * Load the space map disk into the specified range tree. Segments of maptype
50 * are added to the range tree, other segment types are removed.
51 *
52 * Note: space_map_load() will drop sm_lock across dmu_read() calls.
53 * The caller must be OK with this.
54 */
55 int
space_map_load(space_map_t * sm,range_tree_t * rt,maptype_t maptype)56 space_map_load(space_map_t *sm, range_tree_t *rt, maptype_t maptype)
57 {
58 uint64_t *entry, *entry_map, *entry_map_end;
59 uint64_t bufsize, size, offset, end, space;
60 int error = 0;
61
62 ASSERT(MUTEX_HELD(sm->sm_lock));
63
64 end = space_map_length(sm);
65 space = space_map_allocated(sm);
66
67 VERIFY0(range_tree_space(rt));
68
69 if (maptype == SM_FREE) {
70 range_tree_add(rt, sm->sm_start, sm->sm_size);
71 space = sm->sm_size - space;
72 }
73
74 bufsize = MAX(sm->sm_blksz, SPA_MINBLOCKSIZE);
75 entry_map = zio_buf_alloc(bufsize);
76
77 mutex_exit(sm->sm_lock);
78 if (end > bufsize) {
79 dmu_prefetch(sm->sm_os, space_map_object(sm), 0, bufsize,
80 end - bufsize, ZIO_PRIORITY_SYNC_READ);
81 }
82 mutex_enter(sm->sm_lock);
83
84 for (offset = 0; offset < end; offset += bufsize) {
85 size = MIN(end - offset, bufsize);
86 VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0);
87 VERIFY(size != 0);
88 ASSERT3U(sm->sm_blksz, !=, 0);
89
90 dprintf("object=%llu offset=%llx size=%llx\n",
91 space_map_object(sm), offset, size);
92
93 mutex_exit(sm->sm_lock);
94 error = dmu_read(sm->sm_os, space_map_object(sm), offset, size,
95 entry_map, DMU_READ_PREFETCH);
96 mutex_enter(sm->sm_lock);
97 if (error != 0)
98 break;
99
100 entry_map_end = entry_map + (size / sizeof (uint64_t));
101 for (entry = entry_map; entry < entry_map_end; entry++) {
102 uint64_t e = *entry;
103 uint64_t offset, size;
104
105 if (SM_DEBUG_DECODE(e)) /* Skip debug entries */
106 continue;
107
108 offset = (SM_OFFSET_DECODE(e) << sm->sm_shift) +
109 sm->sm_start;
110 size = SM_RUN_DECODE(e) << sm->sm_shift;
111
112 VERIFY0(P2PHASE(offset, 1ULL << sm->sm_shift));
113 VERIFY0(P2PHASE(size, 1ULL << sm->sm_shift));
114 VERIFY3U(offset, >=, sm->sm_start);
115 VERIFY3U(offset + size, <=, sm->sm_start + sm->sm_size);
116 if (SM_TYPE_DECODE(e) == maptype) {
117 VERIFY3U(range_tree_space(rt) + size, <=,
118 sm->sm_size);
119 range_tree_add(rt, offset, size);
120 } else {
121 range_tree_remove(rt, offset, size);
122 }
123 }
124 }
125
126 if (error == 0)
127 VERIFY3U(range_tree_space(rt), ==, space);
128 else
129 range_tree_vacate(rt, NULL, NULL);
130
131 zio_buf_free(entry_map, bufsize);
132 return (error);
133 }
134
135 void
space_map_histogram_clear(space_map_t * sm)136 space_map_histogram_clear(space_map_t *sm)
137 {
138 if (sm->sm_dbuf->db_size != sizeof (space_map_phys_t))
139 return;
140
141 bzero(sm->sm_phys->smp_histogram, sizeof (sm->sm_phys->smp_histogram));
142 }
143
144 boolean_t
space_map_histogram_verify(space_map_t * sm,range_tree_t * rt)145 space_map_histogram_verify(space_map_t *sm, range_tree_t *rt)
146 {
147 /*
148 * Verify that the in-core range tree does not have any
149 * ranges smaller than our sm_shift size.
150 */
151 for (int i = 0; i < sm->sm_shift; i++) {
152 if (rt->rt_histogram[i] != 0)
153 return (B_FALSE);
154 }
155 return (B_TRUE);
156 }
157
158 void
space_map_histogram_add(space_map_t * sm,range_tree_t * rt,dmu_tx_t * tx)159 space_map_histogram_add(space_map_t *sm, range_tree_t *rt, dmu_tx_t *tx)
160 {
161 int idx = 0;
162
163 ASSERT(MUTEX_HELD(rt->rt_lock));
164 ASSERT(dmu_tx_is_syncing(tx));
165 VERIFY3U(space_map_object(sm), !=, 0);
166
167 if (sm->sm_dbuf->db_size != sizeof (space_map_phys_t))
168 return;
169
170 dmu_buf_will_dirty(sm->sm_dbuf, tx);
171
172 ASSERT(space_map_histogram_verify(sm, rt));
173
174 /*
175 * Transfer the content of the range tree histogram to the space
176 * map histogram. The space map histogram contains 32 buckets ranging
177 * between 2^sm_shift to 2^(32+sm_shift-1). The range tree,
178 * however, can represent ranges from 2^0 to 2^63. Since the space
179 * map only cares about allocatable blocks (minimum of sm_shift) we
180 * can safely ignore all ranges in the range tree smaller than sm_shift.
181 */
182 for (int i = sm->sm_shift; i < RANGE_TREE_HISTOGRAM_SIZE; i++) {
183
184 /*
185 * Since the largest histogram bucket in the space map is
186 * 2^(32+sm_shift-1), we need to normalize the values in
187 * the range tree for any bucket larger than that size. For
188 * example given an sm_shift of 9, ranges larger than 2^40
189 * would get normalized as if they were 1TB ranges. Assume
190 * the range tree had a count of 5 in the 2^44 (16TB) bucket,
191 * the calculation below would normalize this to 5 * 2^4 (16).
192 */
193 ASSERT3U(i, >=, idx + sm->sm_shift);
194 sm->sm_phys->smp_histogram[idx] +=
195 rt->rt_histogram[i] << (i - idx - sm->sm_shift);
196
197 /*
198 * Increment the space map's index as long as we haven't
199 * reached the maximum bucket size. Accumulate all ranges
200 * larger than the max bucket size into the last bucket.
201 */
202 if (idx < SPACE_MAP_HISTOGRAM_SIZE - 1) {
203 ASSERT3U(idx + sm->sm_shift, ==, i);
204 idx++;
205 ASSERT3U(idx, <, SPACE_MAP_HISTOGRAM_SIZE);
206 }
207 }
208 }
209
210 uint64_t
space_map_entries(space_map_t * sm,range_tree_t * rt)211 space_map_entries(space_map_t *sm, range_tree_t *rt)
212 {
213 avl_tree_t *t = &rt->rt_root;
214 range_seg_t *rs;
215 uint64_t size, entries;
216
217 /*
218 * All space_maps always have a debug entry so account for it here.
219 */
220 entries = 1;
221
222 /*
223 * Traverse the range tree and calculate the number of space map
224 * entries that would be required to write out the range tree.
225 */
226 for (rs = avl_first(t); rs != NULL; rs = AVL_NEXT(t, rs)) {
227 size = (rs->rs_end - rs->rs_start) >> sm->sm_shift;
228 entries += howmany(size, SM_RUN_MAX);
229 }
230 return (entries);
231 }
232
233 /*
234 * Note: space_map_write() will drop sm_lock across dmu_write() calls.
235 */
236 void
space_map_write(space_map_t * sm,range_tree_t * rt,maptype_t maptype,dmu_tx_t * tx)237 space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
238 dmu_tx_t *tx)
239 {
240 objset_t *os = sm->sm_os;
241 spa_t *spa = dmu_objset_spa(os);
242 avl_tree_t *t = &rt->rt_root;
243 range_seg_t *rs;
244 uint64_t size, total, rt_space, nodes;
245 uint64_t *entry, *entry_map, *entry_map_end;
246 uint64_t expected_entries, actual_entries = 1;
247
248 ASSERT(MUTEX_HELD(rt->rt_lock));
249 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
250 VERIFY3U(space_map_object(sm), !=, 0);
251 dmu_buf_will_dirty(sm->sm_dbuf, tx);
252
253 /*
254 * This field is no longer necessary since the in-core space map
255 * now contains the object number but is maintained for backwards
256 * compatibility.
257 */
258 sm->sm_phys->smp_object = sm->sm_object;
259
260 if (range_tree_space(rt) == 0) {
261 VERIFY3U(sm->sm_object, ==, sm->sm_phys->smp_object);
262 return;
263 }
264
265 if (maptype == SM_ALLOC)
266 sm->sm_phys->smp_alloc += range_tree_space(rt);
267 else
268 sm->sm_phys->smp_alloc -= range_tree_space(rt);
269
270 expected_entries = space_map_entries(sm, rt);
271
272 entry_map = zio_buf_alloc(sm->sm_blksz);
273 entry_map_end = entry_map + (sm->sm_blksz / sizeof (uint64_t));
274 entry = entry_map;
275
276 *entry++ = SM_DEBUG_ENCODE(1) |
277 SM_DEBUG_ACTION_ENCODE(maptype) |
278 SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) |
279 SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx));
280
281 total = 0;
282 nodes = avl_numnodes(&rt->rt_root);
283 rt_space = range_tree_space(rt);
284 for (rs = avl_first(t); rs != NULL; rs = AVL_NEXT(t, rs)) {
285 uint64_t start;
286
287 size = (rs->rs_end - rs->rs_start) >> sm->sm_shift;
288 start = (rs->rs_start - sm->sm_start) >> sm->sm_shift;
289
290 total += size << sm->sm_shift;
291
292 while (size != 0) {
293 uint64_t run_len;
294
295 run_len = MIN(size, SM_RUN_MAX);
296
297 if (entry == entry_map_end) {
298 mutex_exit(rt->rt_lock);
299 dmu_write(os, space_map_object(sm),
300 sm->sm_phys->smp_objsize, sm->sm_blksz,
301 entry_map, tx);
302 mutex_enter(rt->rt_lock);
303 sm->sm_phys->smp_objsize += sm->sm_blksz;
304 entry = entry_map;
305 }
306
307 *entry++ = SM_OFFSET_ENCODE(start) |
308 SM_TYPE_ENCODE(maptype) |
309 SM_RUN_ENCODE(run_len);
310
311 start += run_len;
312 size -= run_len;
313 actual_entries++;
314 }
315 }
316
317 if (entry != entry_map) {
318 size = (entry - entry_map) * sizeof (uint64_t);
319 mutex_exit(rt->rt_lock);
320 dmu_write(os, space_map_object(sm), sm->sm_phys->smp_objsize,
321 size, entry_map, tx);
322 mutex_enter(rt->rt_lock);
323 sm->sm_phys->smp_objsize += size;
324 }
325 ASSERT3U(expected_entries, ==, actual_entries);
326
327 /*
328 * Ensure that the space_map's accounting wasn't changed
329 * while we were in the middle of writing it out.
330 */
331 VERIFY3U(nodes, ==, avl_numnodes(&rt->rt_root));
332 VERIFY3U(range_tree_space(rt), ==, rt_space);
333 VERIFY3U(range_tree_space(rt), ==, total);
334
335 zio_buf_free(entry_map, sm->sm_blksz);
336 }
337
338 static int
space_map_open_impl(space_map_t * sm)339 space_map_open_impl(space_map_t *sm)
340 {
341 int error;
342 u_longlong_t blocks;
343
344 error = dmu_bonus_hold(sm->sm_os, sm->sm_object, sm, &sm->sm_dbuf);
345 if (error)
346 return (error);
347
348 dmu_object_size_from_db(sm->sm_dbuf, &sm->sm_blksz, &blocks);
349 sm->sm_phys = sm->sm_dbuf->db_data;
350 return (0);
351 }
352
353 int
space_map_open(space_map_t ** smp,objset_t * os,uint64_t object,uint64_t start,uint64_t size,uint8_t shift,kmutex_t * lp)354 space_map_open(space_map_t **smp, objset_t *os, uint64_t object,
355 uint64_t start, uint64_t size, uint8_t shift, kmutex_t *lp)
356 {
357 space_map_t *sm;
358 int error;
359
360 ASSERT(*smp == NULL);
361 ASSERT(os != NULL);
362 ASSERT(object != 0);
363
364 sm = kmem_zalloc(sizeof (space_map_t), KM_SLEEP);
365
366 sm->sm_start = start;
367 sm->sm_size = size;
368 sm->sm_shift = shift;
369 sm->sm_lock = lp;
370 sm->sm_os = os;
371 sm->sm_object = object;
372
373 error = space_map_open_impl(sm);
374 if (error != 0) {
375 space_map_close(sm);
376 return (error);
377 }
378
379 *smp = sm;
380
381 return (0);
382 }
383
384 void
space_map_close(space_map_t * sm)385 space_map_close(space_map_t *sm)
386 {
387 if (sm == NULL)
388 return;
389
390 if (sm->sm_dbuf != NULL)
391 dmu_buf_rele(sm->sm_dbuf, sm);
392 sm->sm_dbuf = NULL;
393 sm->sm_phys = NULL;
394
395 kmem_free(sm, sizeof (*sm));
396 }
397
398 void
space_map_truncate(space_map_t * sm,dmu_tx_t * tx)399 space_map_truncate(space_map_t *sm, dmu_tx_t *tx)
400 {
401 objset_t *os = sm->sm_os;
402 spa_t *spa = dmu_objset_spa(os);
403 dmu_object_info_t doi;
404
405 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
406 ASSERT(dmu_tx_is_syncing(tx));
407
408 dmu_object_info_from_db(sm->sm_dbuf, &doi);
409
410 /*
411 * If the space map has the wrong bonus size (because
412 * SPA_FEATURE_SPACEMAP_HISTOGRAM has recently been enabled), or
413 * the wrong block size (because space_map_blksz has changed),
414 * free and re-allocate its object with the updated sizes.
415 *
416 * Otherwise, just truncate the current object.
417 */
418 if ((spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM) &&
419 doi.doi_bonus_size != sizeof (space_map_phys_t)) ||
420 doi.doi_data_block_size != space_map_blksz) {
421 zfs_dbgmsg("txg %llu, spa %s, reallocating: "
422 "old bonus %u, old blocksz %u", dmu_tx_get_txg(tx),
423 spa_name(spa), doi.doi_bonus_size, doi.doi_data_block_size);
424
425 space_map_free(sm, tx);
426 dmu_buf_rele(sm->sm_dbuf, sm);
427
428 sm->sm_object = space_map_alloc(sm->sm_os, tx);
429 VERIFY0(space_map_open_impl(sm));
430 } else {
431 VERIFY0(dmu_free_range(os, space_map_object(sm), 0, -1ULL, tx));
432
433 /*
434 * If the spacemap is reallocated, its histogram
435 * will be reset. Do the same in the common case so that
436 * bugs related to the uncommon case do not go unnoticed.
437 */
438 bzero(sm->sm_phys->smp_histogram,
439 sizeof (sm->sm_phys->smp_histogram));
440 }
441
442 dmu_buf_will_dirty(sm->sm_dbuf, tx);
443 sm->sm_phys->smp_objsize = 0;
444 sm->sm_phys->smp_alloc = 0;
445 }
446
447 /*
448 * Update the in-core space_map allocation and length values.
449 */
450 void
space_map_update(space_map_t * sm)451 space_map_update(space_map_t *sm)
452 {
453 if (sm == NULL)
454 return;
455
456 ASSERT(MUTEX_HELD(sm->sm_lock));
457
458 sm->sm_alloc = sm->sm_phys->smp_alloc;
459 sm->sm_length = sm->sm_phys->smp_objsize;
460 }
461
462 uint64_t
space_map_alloc(objset_t * os,dmu_tx_t * tx)463 space_map_alloc(objset_t *os, dmu_tx_t *tx)
464 {
465 spa_t *spa = dmu_objset_spa(os);
466 uint64_t object;
467 int bonuslen;
468
469 if (spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM)) {
470 spa_feature_incr(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM, tx);
471 bonuslen = sizeof (space_map_phys_t);
472 ASSERT3U(bonuslen, <=, dmu_bonus_max());
473 } else {
474 bonuslen = SPACE_MAP_SIZE_V0;
475 }
476
477 object = dmu_object_alloc(os,
478 DMU_OT_SPACE_MAP, space_map_blksz,
479 DMU_OT_SPACE_MAP_HEADER, bonuslen, tx);
480
481 return (object);
482 }
483
484 void
space_map_free(space_map_t * sm,dmu_tx_t * tx)485 space_map_free(space_map_t *sm, dmu_tx_t *tx)
486 {
487 spa_t *spa;
488
489 if (sm == NULL)
490 return;
491
492 spa = dmu_objset_spa(sm->sm_os);
493 if (spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM)) {
494 dmu_object_info_t doi;
495
496 dmu_object_info_from_db(sm->sm_dbuf, &doi);
497 if (doi.doi_bonus_size != SPACE_MAP_SIZE_V0) {
498 VERIFY(spa_feature_is_active(spa,
499 SPA_FEATURE_SPACEMAP_HISTOGRAM));
500 spa_feature_decr(spa,
501 SPA_FEATURE_SPACEMAP_HISTOGRAM, tx);
502 }
503 }
504
505 VERIFY3U(dmu_object_free(sm->sm_os, space_map_object(sm), tx), ==, 0);
506 sm->sm_object = 0;
507 }
508
509 uint64_t
space_map_object(space_map_t * sm)510 space_map_object(space_map_t *sm)
511 {
512 return (sm != NULL ? sm->sm_object : 0);
513 }
514
515 /*
516 * Returns the already synced, on-disk allocated space.
517 */
518 uint64_t
space_map_allocated(space_map_t * sm)519 space_map_allocated(space_map_t *sm)
520 {
521 return (sm != NULL ? sm->sm_alloc : 0);
522 }
523
524 /*
525 * Returns the already synced, on-disk length;
526 */
527 uint64_t
space_map_length(space_map_t * sm)528 space_map_length(space_map_t *sm)
529 {
530 return (sm != NULL ? sm->sm_length : 0);
531 }
532
533 /*
534 * Returns the allocated space that is currently syncing.
535 */
536 int64_t
space_map_alloc_delta(space_map_t * sm)537 space_map_alloc_delta(space_map_t *sm)
538 {
539 if (sm == NULL)
540 return (0);
541 ASSERT(sm->sm_dbuf != NULL);
542 return (sm->sm_phys->smp_alloc - space_map_allocated(sm));
543 }
544