space_map.c revision 8365e7c9222c4c8080dc66e31c58032c59b1c199
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 2007 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	if (ss != NULL && ss->ss_start <= start && ss->ss_end >= end) {
101		zfs_panic_recover("zfs: allocating allocated segment"
102		    "(offset=%llu size=%llu)\n",
103		    (longlong_t)start, (longlong_t)size);
104		return;
105	}
106
107	/* Make sure we don't overlap with either of our neighbors */
108	VERIFY(ss == NULL);
109
110	ss_before = avl_nearest(&sm->sm_root, where, AVL_BEFORE);
111	ss_after = avl_nearest(&sm->sm_root, where, AVL_AFTER);
112
113	merge_before = (ss_before != NULL && ss_before->ss_end == start);
114	merge_after = (ss_after != NULL && ss_after->ss_start == end);
115
116	if (merge_before && merge_after) {
117		avl_remove(&sm->sm_root, ss_before);
118		ss_after->ss_start = ss_before->ss_start;
119		kmem_free(ss_before, sizeof (*ss_before));
120	} else if (merge_before) {
121		ss_before->ss_end = end;
122	} else if (merge_after) {
123		ss_after->ss_start = start;
124	} else {
125		ss = kmem_alloc(sizeof (*ss), KM_SLEEP);
126		ss->ss_start = start;
127		ss->ss_end = end;
128		avl_insert(&sm->sm_root, ss, where);
129	}
130
131	sm->sm_space += size;
132}
133
134void
135space_map_remove(space_map_t *sm, uint64_t start, uint64_t size)
136{
137	avl_index_t where;
138	space_seg_t ssearch, *ss, *newseg;
139	uint64_t end = start + size;
140	int left_over, right_over;
141
142	ASSERT(MUTEX_HELD(sm->sm_lock));
143	VERIFY(size != 0);
144	VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);
145	VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);
146
147	ssearch.ss_start = start;
148	ssearch.ss_end = end;
149	ss = avl_find(&sm->sm_root, &ssearch, &where);
150
151	/* Make sure we completely overlap with someone */
152	if (ss == NULL) {
153		zfs_panic_recover("zfs: freeing free segment "
154		    "(offset=%llu size=%llu)",
155		    (longlong_t)start, (longlong_t)size);
156		return;
157	}
158	VERIFY3U(ss->ss_start, <=, start);
159	VERIFY3U(ss->ss_end, >=, end);
160	VERIFY(sm->sm_space - size <= sm->sm_size);
161
162	left_over = (ss->ss_start != start);
163	right_over = (ss->ss_end != end);
164
165	if (left_over && right_over) {
166		newseg = kmem_alloc(sizeof (*newseg), KM_SLEEP);
167		newseg->ss_start = end;
168		newseg->ss_end = ss->ss_end;
169		ss->ss_end = start;
170		avl_insert_here(&sm->sm_root, newseg, ss, AVL_AFTER);
171	} else if (left_over) {
172		ss->ss_end = start;
173	} else if (right_over) {
174		ss->ss_start = end;
175	} else {
176		avl_remove(&sm->sm_root, ss);
177		kmem_free(ss, sizeof (*ss));
178	}
179
180	sm->sm_space -= size;
181}
182
183int
184space_map_contains(space_map_t *sm, uint64_t start, uint64_t size)
185{
186	avl_index_t where;
187	space_seg_t ssearch, *ss;
188	uint64_t end = start + size;
189
190	ASSERT(MUTEX_HELD(sm->sm_lock));
191	VERIFY(size != 0);
192	VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0);
193	VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0);
194
195	ssearch.ss_start = start;
196	ssearch.ss_end = end;
197	ss = avl_find(&sm->sm_root, &ssearch, &where);
198
199	return (ss != NULL && ss->ss_start <= start && ss->ss_end >= end);
200}
201
202void
203space_map_vacate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest)
204{
205	space_seg_t *ss;
206	void *cookie = NULL;
207
208	ASSERT(MUTEX_HELD(sm->sm_lock));
209
210	while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {
211		if (func != NULL)
212			func(mdest, ss->ss_start, ss->ss_end - ss->ss_start);
213		kmem_free(ss, sizeof (*ss));
214	}
215	sm->sm_space = 0;
216}
217
218void
219space_map_walk(space_map_t *sm, space_map_func_t *func, space_map_t *mdest)
220{
221	space_seg_t *ss;
222
223	for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss))
224		func(mdest, ss->ss_start, ss->ss_end - ss->ss_start);
225}
226
227void
228space_map_excise(space_map_t *sm, uint64_t start, uint64_t size)
229{
230	avl_tree_t *t = &sm->sm_root;
231	avl_index_t where;
232	space_seg_t *ss, search;
233	uint64_t end = start + size;
234	uint64_t rm_start, rm_end;
235
236	ASSERT(MUTEX_HELD(sm->sm_lock));
237
238	search.ss_start = start;
239	search.ss_end = start;
240
241	for (;;) {
242		ss = avl_find(t, &search, &where);
243
244		if (ss == NULL)
245			ss = avl_nearest(t, where, AVL_AFTER);
246
247		if (ss == NULL || ss->ss_start >= end)
248			break;
249
250		rm_start = MAX(ss->ss_start, start);
251		rm_end = MIN(ss->ss_end, end);
252
253		space_map_remove(sm, rm_start, rm_end - rm_start);
254	}
255}
256
257/*
258 * Replace smd with the union of smd and sms.
259 */
260void
261space_map_union(space_map_t *smd, space_map_t *sms)
262{
263	avl_tree_t *t = &sms->sm_root;
264	space_seg_t *ss;
265
266	ASSERT(MUTEX_HELD(smd->sm_lock));
267
268	/*
269	 * For each source segment, remove any intersections with the
270	 * destination, then add the source segment to the destination.
271	 */
272	for (ss = avl_first(t); ss != NULL; ss = AVL_NEXT(t, ss)) {
273		space_map_excise(smd, ss->ss_start, ss->ss_end - ss->ss_start);
274		space_map_add(smd, ss->ss_start, ss->ss_end - ss->ss_start);
275	}
276}
277
278/*
279 * Wait for any in-progress space_map_load() to complete.
280 */
281void
282space_map_load_wait(space_map_t *sm)
283{
284	ASSERT(MUTEX_HELD(sm->sm_lock));
285
286	while (sm->sm_loading)
287		cv_wait(&sm->sm_load_cv, sm->sm_lock);
288}
289
290/*
291 * Note: space_map_load() will drop sm_lock across dmu_read() calls.
292 * The caller must be OK with this.
293 */
294int
295space_map_load(space_map_t *sm, space_map_ops_t *ops, uint8_t maptype,
296	space_map_obj_t *smo, objset_t *os)
297{
298	uint64_t *entry, *entry_map, *entry_map_end;
299	uint64_t bufsize, size, offset, end, space;
300	uint64_t mapstart = sm->sm_start;
301
302	ASSERT(MUTEX_HELD(sm->sm_lock));
303
304	space_map_load_wait(sm);
305
306	if (sm->sm_loaded)
307		return (0);
308
309	sm->sm_loading = B_TRUE;
310	end = smo->smo_objsize;
311	space = smo->smo_alloc;
312
313	ASSERT(sm->sm_ops == NULL);
314	VERIFY3U(sm->sm_space, ==, 0);
315
316	if (maptype == SM_FREE) {
317		space_map_add(sm, sm->sm_start, sm->sm_size);
318		space = sm->sm_size - space;
319	}
320
321	bufsize = 1ULL << SPACE_MAP_BLOCKSHIFT;
322	entry_map = zio_buf_alloc(bufsize);
323
324	mutex_exit(sm->sm_lock);
325	if (end > bufsize)
326		dmu_prefetch(os, smo->smo_object, bufsize, end - bufsize);
327	mutex_enter(sm->sm_lock);
328
329	for (offset = 0; offset < end; offset += bufsize) {
330		size = MIN(end - offset, bufsize);
331		VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0);
332		VERIFY(size != 0);
333
334		dprintf("object=%llu  offset=%llx  size=%llx\n",
335		    smo->smo_object, offset, size);
336
337		mutex_exit(sm->sm_lock);
338		VERIFY3U(dmu_read(os, smo->smo_object, offset, size,
339		    entry_map), ==, 0);
340		mutex_enter(sm->sm_lock);
341
342		entry_map_end = entry_map + (size / sizeof (uint64_t));
343		for (entry = entry_map; entry < entry_map_end; entry++) {
344			uint64_t e = *entry;
345
346			if (SM_DEBUG_DECODE(e))		/* Skip debug entries */
347				continue;
348
349			(SM_TYPE_DECODE(e) == maptype ?
350			    space_map_add : space_map_remove)(sm,
351			    (SM_OFFSET_DECODE(e) << sm->sm_shift) + mapstart,
352			    SM_RUN_DECODE(e) << sm->sm_shift);
353		}
354	}
355	VERIFY3U(sm->sm_space, ==, space);
356
357	zio_buf_free(entry_map, bufsize);
358
359	sm->sm_loading = B_FALSE;
360	sm->sm_loaded = B_TRUE;
361	sm->sm_ops = ops;
362
363	cv_broadcast(&sm->sm_load_cv);
364
365	if (ops != NULL)
366		ops->smop_load(sm);
367
368	return (0);
369}
370
371void
372space_map_unload(space_map_t *sm)
373{
374	ASSERT(MUTEX_HELD(sm->sm_lock));
375
376	if (sm->sm_loaded && sm->sm_ops != NULL)
377		sm->sm_ops->smop_unload(sm);
378
379	sm->sm_loaded = B_FALSE;
380	sm->sm_ops = NULL;
381
382	space_map_vacate(sm, NULL, NULL);
383}
384
385uint64_t
386space_map_alloc(space_map_t *sm, uint64_t size)
387{
388	uint64_t start;
389
390	start = sm->sm_ops->smop_alloc(sm, size);
391	if (start != -1ULL)
392		space_map_remove(sm, start, size);
393	return (start);
394}
395
396void
397space_map_claim(space_map_t *sm, uint64_t start, uint64_t size)
398{
399	sm->sm_ops->smop_claim(sm, start, size);
400	space_map_remove(sm, start, size);
401}
402
403void
404space_map_free(space_map_t *sm, uint64_t start, uint64_t size)
405{
406	space_map_add(sm, start, size);
407	sm->sm_ops->smop_free(sm, start, size);
408}
409
410/*
411 * Note: space_map_sync() will drop sm_lock across dmu_write() calls.
412 */
413void
414space_map_sync(space_map_t *sm, uint8_t maptype,
415	space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx)
416{
417	spa_t *spa = dmu_objset_spa(os);
418	void *cookie = NULL;
419	space_seg_t *ss;
420	uint64_t bufsize, start, size, run_len;
421	uint64_t *entry, *entry_map, *entry_map_end;
422
423	ASSERT(MUTEX_HELD(sm->sm_lock));
424
425	if (sm->sm_space == 0)
426		return;
427
428	dprintf("object %4llu, txg %llu, pass %d, %c, count %lu, space %llx\n",
429	    smo->smo_object, dmu_tx_get_txg(tx), spa_sync_pass(spa),
430	    maptype == SM_ALLOC ? 'A' : 'F', avl_numnodes(&sm->sm_root),
431	    sm->sm_space);
432
433	if (maptype == SM_ALLOC)
434		smo->smo_alloc += sm->sm_space;
435	else
436		smo->smo_alloc -= sm->sm_space;
437
438	bufsize = (8 + avl_numnodes(&sm->sm_root)) * sizeof (uint64_t);
439	bufsize = MIN(bufsize, 1ULL << SPACE_MAP_BLOCKSHIFT);
440	entry_map = zio_buf_alloc(bufsize);
441	entry_map_end = entry_map + (bufsize / sizeof (uint64_t));
442	entry = entry_map;
443
444	*entry++ = SM_DEBUG_ENCODE(1) |
445	    SM_DEBUG_ACTION_ENCODE(maptype) |
446	    SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) |
447	    SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx));
448
449	while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {
450		size = ss->ss_end - ss->ss_start;
451		start = (ss->ss_start - sm->sm_start) >> sm->sm_shift;
452
453		sm->sm_space -= size;
454		size >>= sm->sm_shift;
455
456		while (size) {
457			run_len = MIN(size, SM_RUN_MAX);
458
459			if (entry == entry_map_end) {
460				mutex_exit(sm->sm_lock);
461				dmu_write(os, smo->smo_object, smo->smo_objsize,
462				    bufsize, entry_map, tx);
463				mutex_enter(sm->sm_lock);
464				smo->smo_objsize += bufsize;
465				entry = entry_map;
466			}
467
468			*entry++ = SM_OFFSET_ENCODE(start) |
469			    SM_TYPE_ENCODE(maptype) |
470			    SM_RUN_ENCODE(run_len);
471
472			start += run_len;
473			size -= run_len;
474		}
475		kmem_free(ss, sizeof (*ss));
476	}
477
478	if (entry != entry_map) {
479		size = (entry - entry_map) * sizeof (uint64_t);
480		mutex_exit(sm->sm_lock);
481		dmu_write(os, smo->smo_object, smo->smo_objsize,
482		    size, entry_map, tx);
483		mutex_enter(sm->sm_lock);
484		smo->smo_objsize += size;
485	}
486
487	zio_buf_free(entry_map, bufsize);
488
489	VERIFY3U(sm->sm_space, ==, 0);
490}
491
492void
493space_map_truncate(space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx)
494{
495	VERIFY(dmu_free_range(os, smo->smo_object, 0, -1ULL, tx) == 0);
496
497	smo->smo_objsize = 0;
498	smo->smo_alloc = 0;
499}
500