kernel/fs/zfs/range_tree.c

   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) 2013, 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/dnode.h>
  33 #include <sys/zio.h>
  34 #include <sys/range_tree.h>
  35
  36 kmem_cache_t *range_seg_cache;
  37
  38 void
  39 range_tree_init(void)
  40 {
  41         ASSERT(range_seg_cache == NULL);
  42         range_seg_cache = kmem_cache_create("range_seg_cache",
  43             sizeof (range_seg_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
  44 }
  45
  46 void
  47 range_tree_fini(void)
  48 {
  49         kmem_cache_destroy(range_seg_cache);
  50         range_seg_cache = NULL;
  51 }
  52
  53 void
  54 range_tree_stat_verify(range_tree_t *rt)
  55 {
  56         range_seg_t *rs;
  57         uint64_t hist[RANGE_TREE_HISTOGRAM_SIZE] = { 0 };
  58         int i;
  59
  60         for (rs = avl_first(&rt->rt_root); rs != NULL;
  61             rs = AVL_NEXT(&rt->rt_root, rs)) {
  62                 uint64_t size = rs->rs_end - rs->rs_start;
  63                 int idx = highbit64(size) - 1;
  64
  65                 hist[idx]++;
  66                 ASSERT3U(hist[idx], !=, 0);
  67         }
  68
  69         for (i = 0; i < RANGE_TREE_HISTOGRAM_SIZE; i++) {
  70                 if (hist[i] != rt->rt_histogram[i]) {
  71                         zfs_dbgmsg("i=%d, hist=%p, hist=%llu, rt_hist=%llu",
  72                             i, hist, hist[i], rt->rt_histogram[i]);
  73                 }
  74                 VERIFY3U(hist[i], ==, rt->rt_histogram[i]);
  75         }
  76 }
  77
  78 static void
  79 range_tree_stat_incr(range_tree_t *rt, range_seg_t *rs)
  80 {
  81         uint64_t size = rs->rs_end - rs->rs_start;
  82         int idx = highbit64(size) - 1;
  83
  84         ASSERT(size != 0);
  85         ASSERT3U(idx, <,
  86             sizeof (rt->rt_histogram) / sizeof (*rt->rt_histogram));
  87
  88         ASSERT(MUTEX_HELD(rt->rt_lock));
  89         rt->rt_histogram[idx]++;
  90         ASSERT3U(rt->rt_histogram[idx], !=, 0);
  91 }
  92
  93 static void
  94 range_tree_stat_decr(range_tree_t *rt, range_seg_t *rs)
  95 {
  96         uint64_t size = rs->rs_end - rs->rs_start;
  97         int idx = highbit64(size) - 1;
  98
  99         ASSERT(size != 0);
 100         ASSERT3U(idx, <,
 101             sizeof (rt->rt_histogram) / sizeof (*rt->rt_histogram));
 102
 103         ASSERT(MUTEX_HELD(rt->rt_lock));
 104         ASSERT3U(rt->rt_histogram[idx], !=, 0);
 105         rt->rt_histogram[idx]--;
 106 }
 107
 108 /*
 109  * NOTE: caller is responsible for all locking.
 110  */
 111 static int
 112 range_tree_seg_compare(const void *x1, const void *x2)
 113 {
 114         const range_seg_t *r1 = x1;
 115         const range_seg_t *r2 = x2;
 116
 117         if (r1->rs_start < r2->rs_start) {
 118                 if (r1->rs_end > r2->rs_start)
 119                         return (0);
 120                 return (-1);
 121         }
 122         if (r1->rs_start > r2->rs_start) {
 123                 if (r1->rs_start < r2->rs_end)
 124                         return (0);
 125                 return (1);
 126         }
 127         return (0);
 128 }
 129
 130 range_tree_t *
 131 range_tree_create(range_tree_ops_t *ops, void *arg, kmutex_t *lp)
 132 {
 133         range_tree_t *rt;
 134
 135         rt = kmem_zalloc(sizeof (range_tree_t), KM_SLEEP);
 136
 137         avl_create(&rt->rt_root, range_tree_seg_compare,
 138             sizeof (range_seg_t), offsetof(range_seg_t, rs_node));
 139
 140         rt->rt_lock = lp;
 141         rt->rt_ops = ops;
 142         rt->rt_arg = arg;
 143
 144         if (rt->rt_ops != NULL)
 145                 rt->rt_ops->rtop_create(rt, rt->rt_arg);
 146
 147         return (rt);
 148 }
 149
 150 void
 151 range_tree_destroy(range_tree_t *rt)
 152 {
 153         VERIFY0(rt->rt_space);
 154
 155         if (rt->rt_ops != NULL)
 156                 rt->rt_ops->rtop_destroy(rt, rt->rt_arg);
 157
 158         avl_destroy(&rt->rt_root);
 159         kmem_free(rt, sizeof (*rt));
 160 }
 161
 162 void
 163 range_tree_add(void *arg, uint64_t start, uint64_t size)
 164 {
 165         range_tree_t *rt = arg;
 166         avl_index_t where;
 167         range_seg_t rsearch, *rs_before, *rs_after, *rs;
 168         uint64_t end = start + size;
 169         boolean_t merge_before, merge_after;
 170
 171         ASSERT(MUTEX_HELD(rt->rt_lock));
 172         VERIFY(size != 0);
 173
 174         rsearch.rs_start = start;
 175         rsearch.rs_end = end;
 176         rs = avl_find(&rt->rt_root, &rsearch, &where);
 177
 178         if (rs != NULL && rs->rs_start <= start && rs->rs_end >= end) {
 179                 zfs_panic_recover("zfs: allocating allocated segment"
 180                     "(offset=%llu size=%llu)\n",
 181                     (longlong_t)start, (longlong_t)size);
 182                 return;
 183         }
 184
 185         /* Make sure we don't overlap with either of our neighbors */
 186         VERIFY(rs == NULL);
 187
 188         rs_before = avl_nearest(&rt->rt_root, where, AVL_BEFORE);
 189         rs_after = avl_nearest(&rt->rt_root, where, AVL_AFTER);
 190
 191         merge_before = (rs_before != NULL && rs_before->rs_end == start);
 192         merge_after = (rs_after != NULL && rs_after->rs_start == end);
 193
 194         if (merge_before && merge_after) {
 195                 avl_remove(&rt->rt_root, rs_before);
 196                 if (rt->rt_ops != NULL) {
 197                         rt->rt_ops->rtop_remove(rt, rs_before, rt->rt_arg);
 198                         rt->rt_ops->rtop_remove(rt, rs_after, rt->rt_arg);
 199                 }
 200
 201                 range_tree_stat_decr(rt, rs_before);
 202                 range_tree_stat_decr(rt, rs_after);
 203
 204                 rs_after->rs_start = rs_before->rs_start;
 205                 kmem_cache_free(range_seg_cache, rs_before);
 206                 rs = rs_after;
 207         } else if (merge_before) {
 208                 if (rt->rt_ops != NULL)
 209                         rt->rt_ops->rtop_remove(rt, rs_before, rt->rt_arg);
 210
 211                 range_tree_stat_decr(rt, rs_before);
 212
 213                 rs_before->rs_end = end;
 214                 rs = rs_before;
 215         } else if (merge_after) {
 216                 if (rt->rt_ops != NULL)
 217                         rt->rt_ops->rtop_remove(rt, rs_after, rt->rt_arg);
 218
 219                 range_tree_stat_decr(rt, rs_after);
 220
 221                 rs_after->rs_start = start;
 222                 rs = rs_after;
 223         } else {
 224                 rs = kmem_cache_alloc(range_seg_cache, KM_SLEEP);
 225                 rs->rs_start = start;
 226                 rs->rs_end = end;
 227                 avl_insert(&rt->rt_root, rs, where);
 228         }
 229
 230         if (rt->rt_ops != NULL)
 231                 rt->rt_ops->rtop_add(rt, rs, rt->rt_arg);
 232
 233         range_tree_stat_incr(rt, rs);
 234         rt->rt_space += size;
 235 }
 236
 237 void
 238 range_tree_remove(void *arg, uint64_t start, uint64_t size)
 239 {
 240         range_tree_t *rt = arg;
 241         avl_index_t where;
 242         range_seg_t rsearch, *rs, *newseg;
 243         uint64_t end = start + size;
 244         boolean_t left_over, right_over;
 245
 246         ASSERT(MUTEX_HELD(rt->rt_lock));
 247         VERIFY3U(size, !=, 0);
 248         VERIFY3U(size, <=, rt->rt_space);
 249
 250         rsearch.rs_start = start;
 251         rsearch.rs_end = end;
 252         rs = avl_find(&rt->rt_root, &rsearch, &where);
 253
 254         /* Make sure we completely overlap with someone */
 255         if (rs == NULL) {
 256                 zfs_panic_recover("zfs: freeing free segment "
 257                     "(offset=%llu size=%llu)",
 258                     (longlong_t)start, (longlong_t)size);
 259                 return;
 260         }
 261         VERIFY3U(rs->rs_start, <=, start);
 262         VERIFY3U(rs->rs_end, >=, end);
 263
 264         left_over = (rs->rs_start != start);
 265         right_over = (rs->rs_end != end);
 266
 267         range_tree_stat_decr(rt, rs);
 268
 269         if (rt->rt_ops != NULL)
 270                 rt->rt_ops->rtop_remove(rt, rs, rt->rt_arg);
 271
 272         if (left_over && right_over) {
 273                 newseg = kmem_cache_alloc(range_seg_cache, KM_SLEEP);
 274                 newseg->rs_start = end;
 275                 newseg->rs_end = rs->rs_end;
 276                 range_tree_stat_incr(rt, newseg);
 277
 278                 rs->rs_end = start;
 279
 280                 avl_insert_here(&rt->rt_root, newseg, rs, AVL_AFTER);
 281                 if (rt->rt_ops != NULL)
 282                         rt->rt_ops->rtop_add(rt, newseg, rt->rt_arg);
 283         } else if (left_over) {
 284                 rs->rs_end = start;
 285         } else if (right_over) {
 286                 rs->rs_start = end;
 287         } else {
 288                 avl_remove(&rt->rt_root, rs);
 289                 kmem_cache_free(range_seg_cache, rs);
 290                 rs = NULL;
 291         }
 292
 293         if (rs != NULL) {
 294                 range_tree_stat_incr(rt, rs);
 295
 296                 if (rt->rt_ops != NULL)
 297                         rt->rt_ops->rtop_add(rt, rs, rt->rt_arg);
 298         }
 299
 300         rt->rt_space -= size;
 301 }
 302
 303 static range_seg_t *
 304 range_tree_find_impl(range_tree_t *rt, uint64_t start, uint64_t size)
 305 {
 306         avl_index_t where;
 307         range_seg_t rsearch;
 308         uint64_t end = start + size;
 309
 310         ASSERT(MUTEX_HELD(rt->rt_lock));
 311         VERIFY(size != 0);
 312
 313         rsearch.rs_start = start;
 314         rsearch.rs_end = end;
 315         return (avl_find(&rt->rt_root, &rsearch, &where));
 316 }
 317
 318 static range_seg_t *
 319 range_tree_find(range_tree_t *rt, uint64_t start, uint64_t size)
 320 {
 321         range_seg_t *rs = range_tree_find_impl(rt, start, size);
 322         if (rs != NULL && rs->rs_start <= start && rs->rs_end >= start + size)
 323                 return (rs);
 324         return (NULL);
 325 }
 326
 327 void
 328 range_tree_verify(range_tree_t *rt, uint64_t off, uint64_t size)
 329 {
 330         range_seg_t *rs;
 331
 332         mutex_enter(rt->rt_lock);
 333         rs = range_tree_find(rt, off, size);
 334         if (rs != NULL)
 335                 panic("freeing free block; rs=%p", (void *)rs);
 336         mutex_exit(rt->rt_lock);
 337 }
 338
 339 boolean_t
 340 range_tree_contains(range_tree_t *rt, uint64_t start, uint64_t size)
 341 {
 342         return (range_tree_find(rt, start, size) != NULL);
 343 }
 344
 345 /*
 346  * Ensure that this range is not in the tree, regardless of whether
 347  * it is currently in the tree.
 348  */
 349 void
 350 range_tree_clear(range_tree_t *rt, uint64_t start, uint64_t size)
 351 {
 352         range_seg_t *rs;
 353
 354         while ((rs = range_tree_find_impl(rt, start, size)) != NULL) {
 355                 uint64_t free_start = MAX(rs->rs_start, start);
 356                 uint64_t free_end = MIN(rs->rs_end, start + size);
 357                 range_tree_remove(rt, free_start, free_end - free_start);
 358         }
 359 }
 360
 361 void
 362 range_tree_swap(range_tree_t **rtsrc, range_tree_t **rtdst)
 363 {
 364         range_tree_t *rt;
 365
 366         ASSERT(MUTEX_HELD((*rtsrc)->rt_lock));
 367         ASSERT0(range_tree_space(*rtdst));
 368         ASSERT0(avl_numnodes(&(*rtdst)->rt_root));
 369
 370         rt = *rtsrc;
 371         *rtsrc = *rtdst;
 372         *rtdst = rt;
 373 }
 374
 375 void
 376 range_tree_vacate(range_tree_t *rt, range_tree_func_t *func, void *arg)
 377 {
 378         range_seg_t *rs;
 379         void *cookie = NULL;
 380
 381         ASSERT(MUTEX_HELD(rt->rt_lock));
 382
 383         if (rt->rt_ops != NULL)
 384                 rt->rt_ops->rtop_vacate(rt, rt->rt_arg);
 385
 386         while ((rs = avl_destroy_nodes(&rt->rt_root, &cookie)) != NULL) {
 387                 if (func != NULL)
 388                         func(arg, rs->rs_start, rs->rs_end - rs->rs_start);
 389                 kmem_cache_free(range_seg_cache, rs);
 390         }
 391
 392         bzero(rt->rt_histogram, sizeof (rt->rt_histogram));
 393         rt->rt_space = 0;
 394 }
 395
 396 void
 397 range_tree_walk(range_tree_t *rt, range_tree_func_t *func, void *arg)
 398 {
 399         range_seg_t *rs;
 400
 401         ASSERT(MUTEX_HELD(rt->rt_lock));
 402
 403         for (rs = avl_first(&rt->rt_root); rs; rs = AVL_NEXT(&rt->rt_root, rs))
 404                 func(arg, rs->rs_start, rs->rs_end - rs->rs_start);
 405 }
 406
 407 uint64_t
 408 range_tree_space(range_tree_t *rt)
 409 {
 410         return (rt->rt_space);
 411 }