space_map.c revision ecc2d604e885a75cc75e647b5641af99d5a6f4a6
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 2006 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26#pragma ident	"%Z%%M%	%I%	%E% SMI"
27
28#include <sys/zfs_context.h>
29#include <sys/spa.h>
30#include <sys/dmu.h>
31#include <sys/zio.h>
32#include <sys/space_map.h>
33
34/*
35 * Space map routines.
36 * NOTE: caller is responsible for all locking.
37 */
38static int
39space_map_seg_compare(const void *x1, const void *x2)
40{
41	const space_seg_t *s1 = x1;
42	const space_seg_t *s2 = x2;
43
44	if (s1->ss_start < s2->ss_start) {
45		if (s1->ss_end > s2->ss_start)
46			return (0);
47		return (-1);
48	}
49	if (s1->ss_start > s2->ss_start) {
50		if (s1->ss_start < s2->ss_end)
51			return (0);
52		return (1);
53	}
54	return (0);
55}
56
57void
58space_map_create(space_map_t *sm, uint64_t start, uint64_t size, uint8_t shift,
59	kmutex_t *lp)
60{
61	bzero(sm, sizeof (*sm));
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
72void
73space_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}
79
80void
81space_map_add(space_map_t *sm, uint64_t start, uint64_t size)
82{
83	avl_index_t where;
84	space_seg_t ssearch, *ss_before, *ss_after, *ss;
85	uint64_t end = start + size;
86	int merge_before, merge_after;
87
88	ASSERT(MUTEX_HELD(sm->sm_lock));
89	VERIFY(size != 0);
90	VERIFY3U(start, >=, sm->sm_start);
91	VERIFY3U(end, <=, sm->sm_start + sm->sm_size);
92	VERIFY(sm->sm_space + size <= sm->sm_size);
93	VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);
94	VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);
95
96	ssearch.ss_start = start;
97	ssearch.ss_end = end;
98	ss = avl_find(&sm->sm_root, &ssearch, &where);
99
100	/* Make sure we don't overlap with either of our neighbors */
101	VERIFY(ss == NULL);
102
103	ss_before = avl_nearest(&sm->sm_root, where, AVL_BEFORE);
104	ss_after = avl_nearest(&sm->sm_root, where, AVL_AFTER);
105
106	merge_before = (ss_before != NULL && ss_before->ss_end == start);
107	merge_after = (ss_after != NULL && ss_after->ss_start == end);
108
109	if (merge_before && merge_after) {
110		avl_remove(&sm->sm_root, ss_before);
111		ss_after->ss_start = ss_before->ss_start;
112		kmem_free(ss_before, sizeof (*ss_before));
113	} else if (merge_before) {
114		ss_before->ss_end = end;
115	} else if (merge_after) {
116		ss_after->ss_start = start;
117	} else {
118		ss = kmem_alloc(sizeof (*ss), KM_SLEEP);
119		ss->ss_start = start;
120		ss->ss_end = end;
121		avl_insert(&sm->sm_root, ss, where);
122	}
123
124	sm->sm_space += size;
125}
126
127void
128space_map_remove(space_map_t *sm, uint64_t start, uint64_t size)
129{
130	avl_index_t where;
131	space_seg_t ssearch, *ss, *newseg;
132	uint64_t end = start + size;
133	int left_over, right_over;
134
135	ASSERT(MUTEX_HELD(sm->sm_lock));
136	VERIFY(size != 0);
137	VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);
138	VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);
139
140	ssearch.ss_start = start;
141	ssearch.ss_end = end;
142	ss = avl_find(&sm->sm_root, &ssearch, &where);
143
144	/* Make sure we completely overlap with someone */
145	VERIFY(ss != NULL);
146	VERIFY3U(ss->ss_start, <=, start);
147	VERIFY3U(ss->ss_end, >=, end);
148	VERIFY(sm->sm_space - size <= sm->sm_size);
149
150	left_over = (ss->ss_start != start);
151	right_over = (ss->ss_end != end);
152
153	if (left_over && right_over) {
154		newseg = kmem_alloc(sizeof (*newseg), KM_SLEEP);
155		newseg->ss_start = end;
156		newseg->ss_end = ss->ss_end;
157		ss->ss_end = start;
158		avl_insert_here(&sm->sm_root, newseg, ss, AVL_AFTER);
159	} else if (left_over) {
160		ss->ss_end = start;
161	} else if (right_over) {
162		ss->ss_start = end;
163	} else {
164		avl_remove(&sm->sm_root, ss);
165		kmem_free(ss, sizeof (*ss));
166	}
167
168	sm->sm_space -= size;
169}
170
171int
172space_map_contains(space_map_t *sm, uint64_t start, uint64_t size)
173{
174	avl_index_t where;
175	space_seg_t ssearch, *ss;
176	uint64_t end = start + size;
177
178	ASSERT(MUTEX_HELD(sm->sm_lock));
179	VERIFY(size != 0);
180	VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);
181	VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);
182
183	ssearch.ss_start = start;
184	ssearch.ss_end = end;
185	ss = avl_find(&sm->sm_root, &ssearch, &where);
186
187	return (ss != NULL && ss->ss_start <= start && ss->ss_end >= end);
188}
189
190void
191space_map_vacate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest)
192{
193	space_seg_t *ss;
194	void *cookie = NULL;
195
196	ASSERT(MUTEX_HELD(sm->sm_lock));
197
198	while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {
199		if (func != NULL)
200			func(mdest, ss->ss_start, ss->ss_end - ss->ss_start);
201		kmem_free(ss, sizeof (*ss));
202	}
203	sm->sm_space = 0;
204}
205
206void
207space_map_walk(space_map_t *sm, space_map_func_t *func, space_map_t *mdest)
208{
209	space_seg_t *ss;
210
211	for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss))
212		func(mdest, ss->ss_start, ss->ss_end - ss->ss_start);
213}
214
215void
216space_map_excise(space_map_t *sm, uint64_t start, uint64_t size)
217{
218	avl_tree_t *t = &sm->sm_root;
219	avl_index_t where;
220	space_seg_t *ss, search;
221	uint64_t end = start + size;
222	uint64_t rm_start, rm_end;
223
224	ASSERT(MUTEX_HELD(sm->sm_lock));
225
226	search.ss_start = start;
227	search.ss_end = start;
228
229	for (;;) {
230		ss = avl_find(t, &search, &where);
231
232		if (ss == NULL)
233			ss = avl_nearest(t, where, AVL_AFTER);
234
235		if (ss == NULL || ss->ss_start >= end)
236			break;
237
238		rm_start = MAX(ss->ss_start, start);
239		rm_end = MIN(ss->ss_end, end);
240
241		space_map_remove(sm, rm_start, rm_end - rm_start);
242	}
243}
244
245/*
246 * Replace smd with the union of smd and sms.
247 */
248void
249space_map_union(space_map_t *smd, space_map_t *sms)
250{
251	avl_tree_t *t = &sms->sm_root;
252	space_seg_t *ss;
253
254	ASSERT(MUTEX_HELD(smd->sm_lock));
255
256	/*
257	 * For each source segment, remove any intersections with the
258	 * destination, then add the source segment to the destination.
259	 */
260	for (ss = avl_first(t); ss != NULL; ss = AVL_NEXT(t, ss)) {
261		space_map_excise(smd, ss->ss_start, ss->ss_end - ss->ss_start);
262		space_map_add(smd, ss->ss_start, ss->ss_end - ss->ss_start);
263	}
264}
265
266/*
267 * Wait for any in-progress space_map_load() to complete.
268 */
269void
270space_map_load_wait(space_map_t *sm)
271{
272	ASSERT(MUTEX_HELD(sm->sm_lock));
273
274	while (sm->sm_loading)
275		cv_wait(&sm->sm_load_cv, sm->sm_lock);
276}
277
278/*
279 * Note: space_map_load() will drop sm_lock across dmu_read() calls.
280 * The caller must be OK with this.
281 */
282int
283space_map_load(space_map_t *sm, space_map_ops_t *ops, uint8_t maptype,
284	space_map_obj_t *smo, objset_t *os)
285{
286	uint64_t *entry, *entry_map, *entry_map_end;
287	uint64_t bufsize, size, offset;
288	uint64_t mapstart = sm->sm_start;
289	uint64_t end = smo->smo_objsize;
290	uint64_t space = smo->smo_alloc;
291
292	ASSERT(MUTEX_HELD(sm->sm_lock));
293
294	space_map_load_wait(sm);
295
296	if (sm->sm_loaded)
297		return (0);
298
299	sm->sm_loading = B_TRUE;
300
301	ASSERT(sm->sm_ops == NULL);
302	VERIFY3U(sm->sm_space, ==, 0);
303
304	if (maptype == SM_FREE) {
305		space_map_add(sm, sm->sm_start, sm->sm_size);
306		space = sm->sm_size - space;
307	}
308
309	bufsize = 1ULL << SPACE_MAP_BLOCKSHIFT;
310	entry_map = zio_buf_alloc(bufsize);
311
312	mutex_exit(sm->sm_lock);
313	if (end > bufsize)
314		dmu_prefetch(os, smo->smo_object, bufsize, end - bufsize);
315	mutex_enter(sm->sm_lock);
316
317	for (offset = 0; offset < end; offset += bufsize) {
318		size = MIN(end - offset, bufsize);
319		VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0);
320		VERIFY(size != 0);
321
322		dprintf("object=%llu  offset=%llx  size=%llx\n",
323		    smo->smo_object, offset, size);
324
325		mutex_exit(sm->sm_lock);
326		VERIFY3U(dmu_read(os, smo->smo_object, offset, size,
327		    entry_map), ==, 0);
328		mutex_enter(sm->sm_lock);
329
330		entry_map_end = entry_map + (size / sizeof (uint64_t));
331		for (entry = entry_map; entry < entry_map_end; entry++) {
332			uint64_t e = *entry;
333
334			if (SM_DEBUG_DECODE(e))		/* Skip debug entries */
335				continue;
336
337			(SM_TYPE_DECODE(e) == maptype ?
338			    space_map_add : space_map_remove)(sm,
339			    (SM_OFFSET_DECODE(e) << sm->sm_shift) + mapstart,
340			    SM_RUN_DECODE(e) << sm->sm_shift);
341		}
342	}
343	VERIFY3U(sm->sm_space, ==, space);
344
345	zio_buf_free(entry_map, bufsize);
346
347	sm->sm_loading = B_FALSE;
348	sm->sm_loaded = B_TRUE;
349	sm->sm_ops = ops;
350
351	cv_broadcast(&sm->sm_load_cv);
352
353	if (ops != NULL)
354		ops->smop_load(sm);
355
356	return (0);
357}
358
359void
360space_map_unload(space_map_t *sm)
361{
362	ASSERT(MUTEX_HELD(sm->sm_lock));
363
364	if (sm->sm_loaded && sm->sm_ops != NULL)
365		sm->sm_ops->smop_unload(sm);
366
367	sm->sm_loaded = B_FALSE;
368	sm->sm_ops = NULL;
369
370	space_map_vacate(sm, NULL, NULL);
371}
372
373uint64_t
374space_map_alloc(space_map_t *sm, uint64_t size)
375{
376	uint64_t start;
377
378	start = sm->sm_ops->smop_alloc(sm, size);
379	if (start != -1ULL)
380		space_map_remove(sm, start, size);
381	return (start);
382}
383
384void
385space_map_claim(space_map_t *sm, uint64_t start, uint64_t size)
386{
387	sm->sm_ops->smop_claim(sm, start, size);
388	space_map_remove(sm, start, size);
389}
390
391void
392space_map_free(space_map_t *sm, uint64_t start, uint64_t size)
393{
394	space_map_add(sm, start, size);
395	sm->sm_ops->smop_free(sm, start, size);
396}
397
398/*
399 * Note: space_map_sync() will drop sm_lock across dmu_write() calls.
400 */
401void
402space_map_sync(space_map_t *sm, uint8_t maptype,
403	space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx)
404{
405	spa_t *spa = dmu_objset_spa(os);
406	void *cookie = NULL;
407	space_seg_t *ss;
408	uint64_t bufsize, start, size, run_len;
409	uint64_t *entry, *entry_map, *entry_map_end;
410
411	ASSERT(MUTEX_HELD(sm->sm_lock));
412
413	if (sm->sm_space == 0)
414		return;
415
416	dprintf("object %4llu, txg %llu, pass %d, %c, count %lu, space %llx\n",
417	    smo->smo_object, dmu_tx_get_txg(tx), spa_sync_pass(spa),
418	    maptype == SM_ALLOC ? 'A' : 'F', avl_numnodes(&sm->sm_root),
419	    sm->sm_space);
420
421	if (maptype == SM_ALLOC)
422		smo->smo_alloc += sm->sm_space;
423	else
424		smo->smo_alloc -= sm->sm_space;
425
426	bufsize = (8 + avl_numnodes(&sm->sm_root)) * sizeof (uint64_t);
427	bufsize = MIN(bufsize, 1ULL << SPACE_MAP_BLOCKSHIFT);
428	entry_map = zio_buf_alloc(bufsize);
429	entry_map_end = entry_map + (bufsize / sizeof (uint64_t));
430	entry = entry_map;
431
432	*entry++ = SM_DEBUG_ENCODE(1) |
433	    SM_DEBUG_ACTION_ENCODE(maptype) |
434	    SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) |
435	    SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx));
436
437	while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {
438		size = ss->ss_end - ss->ss_start;
439		start = (ss->ss_start - sm->sm_start) >> sm->sm_shift;
440
441		sm->sm_space -= size;
442		size >>= sm->sm_shift;
443
444		while (size) {
445			run_len = MIN(size, SM_RUN_MAX);
446
447			if (entry == entry_map_end) {
448				mutex_exit(sm->sm_lock);
449				dmu_write(os, smo->smo_object, smo->smo_objsize,
450				    bufsize, entry_map, tx);
451				mutex_enter(sm->sm_lock);
452				smo->smo_objsize += bufsize;
453				entry = entry_map;
454			}
455
456			*entry++ = SM_OFFSET_ENCODE(start) |
457			    SM_TYPE_ENCODE(maptype) |
458			    SM_RUN_ENCODE(run_len);
459
460			start += run_len;
461			size -= run_len;
462		}
463		kmem_free(ss, sizeof (*ss));
464	}
465
466	if (entry != entry_map) {
467		size = (entry - entry_map) * sizeof (uint64_t);
468		mutex_exit(sm->sm_lock);
469		dmu_write(os, smo->smo_object, smo->smo_objsize,
470		    size, entry_map, tx);
471		mutex_enter(sm->sm_lock);
472		smo->smo_objsize += size;
473	}
474
475	zio_buf_free(entry_map, bufsize);
476
477	VERIFY3U(sm->sm_space, ==, 0);
478}
479
480void
481space_map_truncate(space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx)
482{
483	VERIFY(dmu_free_range(os, smo->smo_object, 0, -1ULL, tx) == 0);
484
485	smo->smo_objsize = 0;
486	smo->smo_alloc = 0;
487}
488