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 SYSCTL_DECL(_vfs_zfs);
41
42 /*
43 * The data for a given space map can be kept on blocks of any size.
44 * Larger blocks entail fewer i/o operations, but they also cause the
45 * DMU to keep more data in-core, and also to waste more i/o bandwidth
46 * when only a few blocks have changed since the last transaction group.
47 */
48 int space_map_blksz = (1 << 12);
49 SYSCTL_INT(_vfs_zfs, OID_AUTO, space_map_blksz, CTLFLAG_RDTUN, &space_map_blksz, 0,
50 "Maximum block size for space map. Must be power of 2 and greater than 4096.");
51
52 /*
53 * Load the space map disk into the specified range tree. Segments of maptype
54 * are added to the range tree, other segment types are removed.
55 *
56 * Note: space_map_load() will drop sm_lock across dmu_read() calls.
57 * The caller must be OK with this.
58 */
59 int
space_map_load(space_map_t * sm,range_tree_t * rt,maptype_t maptype)60 space_map_load(space_map_t *sm, range_tree_t *rt, maptype_t maptype)
61 {
62 uint64_t *entry, *entry_map, *entry_map_end;
63 uint64_t bufsize, size, offset, end, space;
64 int error = 0;
65
66 ASSERT(MUTEX_HELD(sm->sm_lock));
67
68 end = space_map_length(sm);
69 space = space_map_allocated(sm);
70
71 VERIFY0(range_tree_space(rt));
72
73 if (maptype == SM_FREE) {
74 range_tree_add(rt, sm->sm_start, sm->sm_size);
75 space = sm->sm_size - space;
76 }
77
78 bufsize = MAX(sm->sm_blksz, SPA_MINBLOCKSIZE);
79 entry_map = zio_buf_alloc(bufsize);
80
81 mutex_exit(sm->sm_lock);
82 if (end > bufsize) {
83 dmu_prefetch(sm->sm_os, space_map_object(sm), 0, bufsize,
84 end - bufsize, ZIO_PRIORITY_SYNC_READ);
85 }
86 mutex_enter(sm->sm_lock);
87
88 for (offset = 0; offset < end; offset += bufsize) {
89 size = MIN(end - offset, bufsize);
90 VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0);
91 VERIFY(size != 0);
92 ASSERT3U(sm->sm_blksz, !=, 0);
93
94 dprintf("object=%llu offset=%llx size=%llx\n",
95 space_map_object(sm), offset, size);
96
97 mutex_exit(sm->sm_lock);
98 error = dmu_read(sm->sm_os, space_map_object(sm), offset, size,
99 entry_map, DMU_READ_PREFETCH);
100 mutex_enter(sm->sm_lock);
101 if (error != 0)
102 break;
103
104 entry_map_end = entry_map + (size / sizeof (uint64_t));
105 for (entry = entry_map; entry < entry_map_end; entry++) {
106 uint64_t e = *entry;
107 uint64_t offset, size;
108
109 if (SM_DEBUG_DECODE(e)) /* Skip debug entries */
110 continue;
111
112 offset = (SM_OFFSET_DECODE(e) << sm->sm_shift) +
113 sm->sm_start;
114 size = SM_RUN_DECODE(e) << sm->sm_shift;
115
116 VERIFY0(P2PHASE(offset, 1ULL << sm->sm_shift));
117 VERIFY0(P2PHASE(size, 1ULL << sm->sm_shift));
118 VERIFY3U(offset, >=, sm->sm_start);
119 VERIFY3U(offset + size, <=, sm->sm_start + sm->sm_size);
120 if (SM_TYPE_DECODE(e) == maptype) {
121 VERIFY3U(range_tree_space(rt) + size, <=,
122 sm->sm_size);
123 range_tree_add(rt, offset, size);
124 } else {
125 range_tree_remove(rt, offset, size);
126 }
127 }
128 }
129
130 if (error == 0)
131 VERIFY3U(range_tree_space(rt), ==, space);
132 else
133 range_tree_vacate(rt, NULL, NULL);
134
135 zio_buf_free(entry_map, bufsize);
136 return (error);
137 }
138
139 void
space_map_histogram_clear(space_map_t * sm)140 space_map_histogram_clear(space_map_t *sm)
141 {
142 if (sm->sm_dbuf->db_size != sizeof (space_map_phys_t))
143 return;
144
145 bzero(sm->sm_phys->smp_histogram, sizeof (sm->sm_phys->smp_histogram));
146 }
147
148 boolean_t
space_map_histogram_verify(space_map_t * sm,range_tree_t * rt)149 space_map_histogram_verify(space_map_t *sm, range_tree_t *rt)
150 {
151 /*
152 * Verify that the in-core range tree does not have any
153 * ranges smaller than our sm_shift size.
154 */
155 for (int i = 0; i < sm->sm_shift; i++) {
156 if (rt->rt_histogram[i] != 0)
157 return (B_FALSE);
158 }
159 return (B_TRUE);
160 }
161
162 void
space_map_histogram_add(space_map_t * sm,range_tree_t * rt,dmu_tx_t * tx)163 space_map_histogram_add(space_map_t *sm, range_tree_t *rt, dmu_tx_t *tx)
164 {
165 int idx = 0;
166
167 ASSERT(MUTEX_HELD(rt->rt_lock));
168 ASSERT(dmu_tx_is_syncing(tx));
169 VERIFY3U(space_map_object(sm), !=, 0);
170
171 if (sm->sm_dbuf->db_size != sizeof (space_map_phys_t))
172 return;
173
174 dmu_buf_will_dirty(sm->sm_dbuf, tx);
175
176 ASSERT(space_map_histogram_verify(sm, rt));
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 - 1) {
206 ASSERT3U(idx + sm->sm_shift, ==, i);
207 idx++;
208 ASSERT3U(idx, <, SPACE_MAP_HISTOGRAM_SIZE);
209 }
210 }
211 }
212
213 uint64_t
space_map_entries(space_map_t * sm,range_tree_t * rt)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 /*
237 * Note: space_map_write() will drop sm_lock across dmu_write() calls.
238 */
239 void
space_map_write(space_map_t * sm,range_tree_t * rt,maptype_t maptype,dmu_tx_t * tx)240 space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
241 dmu_tx_t *tx)
242 {
243 objset_t *os = sm->sm_os;
244 spa_t *spa = dmu_objset_spa(os);
245 avl_tree_t *t = &rt->rt_root;
246 range_seg_t *rs;
247 uint64_t size, total, rt_space, nodes;
248 uint64_t *entry, *entry_map, *entry_map_end;
249 uint64_t expected_entries, actual_entries = 1;
250
251 ASSERT(MUTEX_HELD(rt->rt_lock));
252 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
253 VERIFY3U(space_map_object(sm), !=, 0);
254 dmu_buf_will_dirty(sm->sm_dbuf, tx);
255
256 /*
257 * This field is no longer necessary since the in-core space map
258 * now contains the object number but is maintained for backwards
259 * compatibility.
260 */
261 sm->sm_phys->smp_object = sm->sm_object;
262
263 if (range_tree_space(rt) == 0) {
264 VERIFY3U(sm->sm_object, ==, sm->sm_phys->smp_object);
265 return;
266 }
267
268 if (maptype == SM_ALLOC)
269 sm->sm_phys->smp_alloc += range_tree_space(rt);
270 else
271 sm->sm_phys->smp_alloc -= range_tree_space(rt);
272
273 expected_entries = space_map_entries(sm, rt);
274
275 entry_map = zio_buf_alloc(sm->sm_blksz);
276 entry_map_end = entry_map + (sm->sm_blksz / sizeof (uint64_t));
277 entry = entry_map;
278
279 *entry++ = SM_DEBUG_ENCODE(1) |
280 SM_DEBUG_ACTION_ENCODE(maptype) |
281 SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) |
282 SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx));
283
284 total = 0;
285 nodes = avl_numnodes(&rt->rt_root);
286 rt_space = range_tree_space(rt);
287 for (rs = avl_first(t); rs != NULL; rs = AVL_NEXT(t, rs)) {
288 uint64_t start;
289
290 size = (rs->rs_end - rs->rs_start) >> sm->sm_shift;
291 start = (rs->rs_start - sm->sm_start) >> sm->sm_shift;
292
293 total += size << sm->sm_shift;
294
295 while (size != 0) {
296 uint64_t run_len;
297
298 run_len = MIN(size, SM_RUN_MAX);
299
300 if (entry == entry_map_end) {
301 mutex_exit(rt->rt_lock);
302 dmu_write(os, space_map_object(sm),
303 sm->sm_phys->smp_objsize, sm->sm_blksz,
304 entry_map, tx);
305 mutex_enter(rt->rt_lock);
306 sm->sm_phys->smp_objsize += sm->sm_blksz;
307 entry = entry_map;
308 }
309
310 *entry++ = SM_OFFSET_ENCODE(start) |
311 SM_TYPE_ENCODE(maptype) |
312 SM_RUN_ENCODE(run_len);
313
314 start += run_len;
315 size -= run_len;
316 actual_entries++;
317 }
318 }
319
320 if (entry != entry_map) {
321 size = (entry - entry_map) * sizeof (uint64_t);
322 mutex_exit(rt->rt_lock);
323 dmu_write(os, space_map_object(sm), sm->sm_phys->smp_objsize,
324 size, entry_map, tx);
325 mutex_enter(rt->rt_lock);
326 sm->sm_phys->smp_objsize += size;
327 }
328 ASSERT3U(expected_entries, ==, actual_entries);
329
330 /*
331 * Ensure that the space_map's accounting wasn't changed
332 * while we were in the middle of writing it out.
333 */
334 VERIFY3U(nodes, ==, avl_numnodes(&rt->rt_root));
335 VERIFY3U(range_tree_space(rt), ==, rt_space);
336 VERIFY3U(range_tree_space(rt), ==, total);
337
338 zio_buf_free(entry_map, sm->sm_blksz);
339 }
340
341 static int
space_map_open_impl(space_map_t * sm)342 space_map_open_impl(space_map_t *sm)
343 {
344 int error;
345 u_longlong_t blocks;
346
347 error = dmu_bonus_hold(sm->sm_os, sm->sm_object, sm, &sm->sm_dbuf);
348 if (error)
349 return (error);
350
351 dmu_object_size_from_db(sm->sm_dbuf, &sm->sm_blksz, &blocks);
352 sm->sm_phys = sm->sm_dbuf->db_data;
353 return (0);
354 }
355
356 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)357 space_map_open(space_map_t **smp, objset_t *os, uint64_t object,
358 uint64_t start, uint64_t size, uint8_t shift, kmutex_t *lp)
359 {
360 space_map_t *sm;
361 int error;
362
363 ASSERT(*smp == NULL);
364 ASSERT(os != NULL);
365 ASSERT(object != 0);
366
367 sm = kmem_zalloc(sizeof (space_map_t), KM_SLEEP);
368
369 sm->sm_start = start;
370 sm->sm_size = size;
371 sm->sm_shift = shift;
372 sm->sm_lock = lp;
373 sm->sm_os = os;
374 sm->sm_object = object;
375
376 error = space_map_open_impl(sm);
377 if (error != 0) {
378 space_map_close(sm);
379 return (error);
380 }
381
382 *smp = sm;
383
384 return (0);
385 }
386
387 void
space_map_close(space_map_t * sm)388 space_map_close(space_map_t *sm)
389 {
390 if (sm == NULL)
391 return;
392
393 if (sm->sm_dbuf != NULL)
394 dmu_buf_rele(sm->sm_dbuf, sm);
395 sm->sm_dbuf = NULL;
396 sm->sm_phys = NULL;
397
398 kmem_free(sm, sizeof (*sm));
399 }
400
401 void
space_map_truncate(space_map_t * sm,dmu_tx_t * tx)402 space_map_truncate(space_map_t *sm, dmu_tx_t *tx)
403 {
404 objset_t *os = sm->sm_os;
405 spa_t *spa = dmu_objset_spa(os);
406 dmu_object_info_t doi;
407
408 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
409 ASSERT(dmu_tx_is_syncing(tx));
410
411 dmu_object_info_from_db(sm->sm_dbuf, &doi);
412
413 /*
414 * If the space map has the wrong bonus size (because
415 * SPA_FEATURE_SPACEMAP_HISTOGRAM has recently been enabled), or
416 * the wrong block size (because space_map_blksz has changed),
417 * free and re-allocate its object with the updated sizes.
418 *
419 * Otherwise, just truncate the current object.
420 */
421 if ((spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM) &&
422 doi.doi_bonus_size != sizeof (space_map_phys_t)) ||
423 doi.doi_data_block_size != space_map_blksz) {
424 zfs_dbgmsg("txg %llu, spa %s, reallocating: "
425 "old bonus %u, old blocksz %u", dmu_tx_get_txg(tx),
426 spa_name(spa), doi.doi_bonus_size, doi.doi_data_block_size);
427
428 space_map_free(sm, tx);
429 dmu_buf_rele(sm->sm_dbuf, sm);
430
431 sm->sm_object = space_map_alloc(sm->sm_os, tx);
432 VERIFY0(space_map_open_impl(sm));
433 } else {
434 VERIFY0(dmu_free_range(os, space_map_object(sm), 0, -1ULL, tx));
435
436 /*
437 * If the spacemap is reallocated, its histogram
438 * will be reset. Do the same in the common case so that
439 * bugs related to the uncommon case do not go unnoticed.
440 */
441 bzero(sm->sm_phys->smp_histogram,
442 sizeof (sm->sm_phys->smp_histogram));
443 }
444
445 dmu_buf_will_dirty(sm->sm_dbuf, tx);
446 sm->sm_phys->smp_objsize = 0;
447 sm->sm_phys->smp_alloc = 0;
448 }
449
450 /*
451 * Update the in-core space_map allocation and length values.
452 */
453 void
space_map_update(space_map_t * sm)454 space_map_update(space_map_t *sm)
455 {
456 if (sm == NULL)
457 return;
458
459 ASSERT(MUTEX_HELD(sm->sm_lock));
460
461 sm->sm_alloc = sm->sm_phys->smp_alloc;
462 sm->sm_length = sm->sm_phys->smp_objsize;
463 }
464
465 uint64_t
space_map_alloc(objset_t * os,dmu_tx_t * tx)466 space_map_alloc(objset_t *os, dmu_tx_t *tx)
467 {
468 spa_t *spa = dmu_objset_spa(os);
469 uint64_t object;
470 int bonuslen;
471
472 if (spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM)) {
473 spa_feature_incr(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM, tx);
474 bonuslen = sizeof (space_map_phys_t);
475 ASSERT3U(bonuslen, <=, dmu_bonus_max());
476 } else {
477 bonuslen = SPACE_MAP_SIZE_V0;
478 }
479
480 object = dmu_object_alloc(os,
481 DMU_OT_SPACE_MAP, space_map_blksz,
482 DMU_OT_SPACE_MAP_HEADER, bonuslen, tx);
483
484 return (object);
485 }
486
487 void
space_map_free(space_map_t * sm,dmu_tx_t * tx)488 space_map_free(space_map_t *sm, dmu_tx_t *tx)
489 {
490 spa_t *spa;
491
492 if (sm == NULL)
493 return;
494
495 spa = dmu_objset_spa(sm->sm_os);
496 if (spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM)) {
497 dmu_object_info_t doi;
498
499 dmu_object_info_from_db(sm->sm_dbuf, &doi);
500 if (doi.doi_bonus_size != SPACE_MAP_SIZE_V0) {
501 VERIFY(spa_feature_is_active(spa,
502 SPA_FEATURE_SPACEMAP_HISTOGRAM));
503 spa_feature_decr(spa,
504 SPA_FEATURE_SPACEMAP_HISTOGRAM, tx);
505 }
506 }
507
508 VERIFY3U(dmu_object_free(sm->sm_os, space_map_object(sm), tx), ==, 0);
509 sm->sm_object = 0;
510 }
511
512 uint64_t
space_map_object(space_map_t * sm)513 space_map_object(space_map_t *sm)
514 {
515 return (sm != NULL ? sm->sm_object : 0);
516 }
517
518 /*
519 * Returns the already synced, on-disk allocated space.
520 */
521 uint64_t
space_map_allocated(space_map_t * sm)522 space_map_allocated(space_map_t *sm)
523 {
524 return (sm != NULL ? sm->sm_alloc : 0);
525 }
526
527 /*
528 * Returns the already synced, on-disk length;
529 */
530 uint64_t
space_map_length(space_map_t * sm)531 space_map_length(space_map_t *sm)
532 {
533 return (sm != NULL ? sm->sm_length : 0);
534 }
535
536 /*
537 * Returns the allocated space that is currently syncing.
538 */
539 int64_t
space_map_alloc_delta(space_map_t * sm)540 space_map_alloc_delta(space_map_t *sm)
541 {
542 if (sm == NULL)
543 return (0);
544 ASSERT(sm->sm_dbuf != NULL);
545 return (sm->sm_phys->smp_alloc - space_map_allocated(sm));
546 }
547