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      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	"@(#)space_map.c	1.6	07/10/24 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 	int error = 0;
    302 
    303 	ASSERT(MUTEX_HELD(sm->sm_lock));
    304 
    305 	space_map_load_wait(sm);
    306 
    307 	if (sm->sm_loaded)
    308 		return (0);
    309 
    310 	sm->sm_loading = B_TRUE;
    311 	end = smo->smo_objsize;
    312 	space = smo->smo_alloc;
    313 
    314 	ASSERT(sm->sm_ops == NULL);
    315 	VERIFY3U(sm->sm_space, ==, 0);
    316 
    317 	if (maptype == SM_FREE) {
    318 		space_map_add(sm, sm->sm_start, sm->sm_size);
    319 		space = sm->sm_size - space;
    320 	}
    321 
    322 	bufsize = 1ULL << SPACE_MAP_BLOCKSHIFT;
    323 	entry_map = zio_buf_alloc(bufsize);
    324 
    325 	mutex_exit(sm->sm_lock);
    326 	if (end > bufsize)
    327 		dmu_prefetch(os, smo->smo_object, bufsize, end - bufsize);
    328 	mutex_enter(sm->sm_lock);
    329 
    330 	for (offset = 0; offset < end; offset += bufsize) {
    331 		size = MIN(end - offset, bufsize);
    332 		VERIFY(P2PHASE(size, sizeof (uint64_t)) == 0);
    333 		VERIFY(size != 0);
    334 
    335 		dprintf("object=%llu  offset=%llx  size=%llx\n",
    336 		    smo->smo_object, offset, size);
    337 
    338 		mutex_exit(sm->sm_lock);
    339 		error = dmu_read(os, smo->smo_object, offset, size, entry_map);
    340 		mutex_enter(sm->sm_lock);
    341 		if (error != 0)
    342 			goto out;
    343 
    344 		entry_map_end = entry_map + (size / sizeof (uint64_t));
    345 		for (entry = entry_map; entry < entry_map_end; entry++) {
    346 			uint64_t e = *entry;
    347 
    348 			if (SM_DEBUG_DECODE(e))		/* Skip debug entries */
    349 				continue;
    350 
    351 			(SM_TYPE_DECODE(e) == maptype ?
    352 			    space_map_add : space_map_remove)(sm,
    353 			    (SM_OFFSET_DECODE(e) << sm->sm_shift) + mapstart,
    354 			    SM_RUN_DECODE(e) << sm->sm_shift);
    355 		}
    356 	}
    357 	VERIFY3U(sm->sm_space, ==, space);
    358 
    359 	sm->sm_loaded = B_TRUE;
    360 	sm->sm_ops = ops;
    361 out:
    362 	zio_buf_free(entry_map, bufsize);
    363 
    364 	sm->sm_loading = B_FALSE;
    365 
    366 	cv_broadcast(&sm->sm_load_cv);
    367 
    368 	if (!error && ops != NULL)
    369 		ops->smop_load(sm);
    370 
    371 	return (error);
    372 }
    373 
    374 void
    375 space_map_unload(space_map_t *sm)
    376 {
    377 	ASSERT(MUTEX_HELD(sm->sm_lock));
    378 
    379 	if (sm->sm_loaded && sm->sm_ops != NULL)
    380 		sm->sm_ops->smop_unload(sm);
    381 
    382 	sm->sm_loaded = B_FALSE;
    383 	sm->sm_ops = NULL;
    384 
    385 	space_map_vacate(sm, NULL, NULL);
    386 }
    387 
    388 uint64_t
    389 space_map_alloc(space_map_t *sm, uint64_t size)
    390 {
    391 	uint64_t start;
    392 
    393 	start = sm->sm_ops->smop_alloc(sm, size);
    394 	if (start != -1ULL)
    395 		space_map_remove(sm, start, size);
    396 	return (start);
    397 }
    398 
    399 void
    400 space_map_claim(space_map_t *sm, uint64_t start, uint64_t size)
    401 {
    402 	sm->sm_ops->smop_claim(sm, start, size);
    403 	space_map_remove(sm, start, size);
    404 }
    405 
    406 void
    407 space_map_free(space_map_t *sm, uint64_t start, uint64_t size)
    408 {
    409 	space_map_add(sm, start, size);
    410 	sm->sm_ops->smop_free(sm, start, size);
    411 }
    412 
    413 /*
    414  * Note: space_map_sync() will drop sm_lock across dmu_write() calls.
    415  */
    416 void
    417 space_map_sync(space_map_t *sm, uint8_t maptype,
    418 	space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx)
    419 {
    420 	spa_t *spa = dmu_objset_spa(os);
    421 	void *cookie = NULL;
    422 	space_seg_t *ss;
    423 	uint64_t bufsize, start, size, run_len;
    424 	uint64_t *entry, *entry_map, *entry_map_end;
    425 
    426 	ASSERT(MUTEX_HELD(sm->sm_lock));
    427 
    428 	if (sm->sm_space == 0)
    429 		return;
    430 
    431 	dprintf("object %4llu, txg %llu, pass %d, %c, count %lu, space %llx\n",
    432 	    smo->smo_object, dmu_tx_get_txg(tx), spa_sync_pass(spa),
    433 	    maptype == SM_ALLOC ? 'A' : 'F', avl_numnodes(&sm->sm_root),
    434 	    sm->sm_space);
    435 
    436 	if (maptype == SM_ALLOC)
    437 		smo->smo_alloc += sm->sm_space;
    438 	else
    439 		smo->smo_alloc -= sm->sm_space;
    440 
    441 	bufsize = (8 + avl_numnodes(&sm->sm_root)) * sizeof (uint64_t);
    442 	bufsize = MIN(bufsize, 1ULL << SPACE_MAP_BLOCKSHIFT);
    443 	entry_map = zio_buf_alloc(bufsize);
    444 	entry_map_end = entry_map + (bufsize / sizeof (uint64_t));
    445 	entry = entry_map;
    446 
    447 	*entry++ = SM_DEBUG_ENCODE(1) |
    448 	    SM_DEBUG_ACTION_ENCODE(maptype) |
    449 	    SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) |
    450 	    SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx));
    451 
    452 	while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {
    453 		size = ss->ss_end - ss->ss_start;
    454 		start = (ss->ss_start - sm->sm_start) >> sm->sm_shift;
    455 
    456 		sm->sm_space -= size;
    457 		size >>= sm->sm_shift;
    458 
    459 		while (size) {
    460 			run_len = MIN(size, SM_RUN_MAX);
    461 
    462 			if (entry == entry_map_end) {
    463 				mutex_exit(sm->sm_lock);
    464 				dmu_write(os, smo->smo_object, smo->smo_objsize,
    465 				    bufsize, entry_map, tx);
    466 				mutex_enter(sm->sm_lock);
    467 				smo->smo_objsize += bufsize;
    468 				entry = entry_map;
    469 			}
    470 
    471 			*entry++ = SM_OFFSET_ENCODE(start) |
    472 			    SM_TYPE_ENCODE(maptype) |
    473 			    SM_RUN_ENCODE(run_len);
    474 
    475 			start += run_len;
    476 			size -= run_len;
    477 		}
    478 		kmem_free(ss, sizeof (*ss));
    479 	}
    480 
    481 	if (entry != entry_map) {
    482 		size = (entry - entry_map) * sizeof (uint64_t);
    483 		mutex_exit(sm->sm_lock);
    484 		dmu_write(os, smo->smo_object, smo->smo_objsize,
    485 		    size, entry_map, tx);
    486 		mutex_enter(sm->sm_lock);
    487 		smo->smo_objsize += size;
    488 	}
    489 
    490 	zio_buf_free(entry_map, bufsize);
    491 
    492 	VERIFY3U(sm->sm_space, ==, 0);
    493 }
    494 
    495 void
    496 space_map_truncate(space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx)
    497 {
    498 	VERIFY(dmu_free_range(os, smo->smo_object, 0, -1ULL, tx) == 0);
    499 
    500 	smo->smo_objsize = 0;
    501 	smo->smo_alloc = 0;
    502 }
    503