xref: /titanic_44/usr/src/uts/common/fs/zfs/space_map.c (revision 990b4856d0eaada6f8140335733a1b1771ed2746)
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  */
38 static int
39 space_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 
57 void
58 space_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 
72 void
73 space_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 
80 void
81 space_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 
134 void
135 space_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 
183 int
184 space_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 
202 void
203 space_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 
218 void
219 space_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 
227 void
228 space_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  */
260 void
261 space_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  */
281 void
282 space_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  */
294 int
295 space_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 
371 void
372 space_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 
385 uint64_t
386 space_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 
396 void
397 space_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 
403 void
404 space_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  */
413 void
414 space_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 
492 void
493 space_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