| 1 | |
| 2 | |
| 3 | * Copyright (C) 2011 Red Hat, Inc.
|
| 4 | *
|
| 5 | * This file is released under the GPL.
|
| 6 |
|
| 7 |
|
| 8 | #include "dm-btree-internal.h"
|
| 9 | #include "dm-space-map.h"
|
| 10 | #include "dm-transaction-manager.h"
|
| 11 |
|
| 12 | #include <linux/export.h>
|
| 13 | #include <linux/device-mapper.h>
|
| 14 |
|
| 15 | #define DM_MSG_PREFIX "btree"
|
| 16 |
|
| 17 | |
| 18 | *--------------------------------------------------------------
|
| 19 | * Array manipulation
|
| 20 | *--------------------------------------------------------------
|
| 21 |
|
| 22 | static void memcpy_disk(void *dest, const void *src, size_t len)
|
| 23 | __dm_written_to_disk(src)
|
| 24 | {
|
| 25 | memcpy(dest, src, len);
|
| 26 | __dm_unbless_for_disk(src);
|
| 27 | }
|
| 28 |
|
| 29 | static void array_insert(void *base, size_t elt_size, unsigned int nr_elts,
|
| 30 | unsigned int index, void *elt)
|
| 31 | __dm_written_to_disk(elt)
|
| 32 | {
|
| 33 | if (index < nr_elts)
|
| 34 | memmove(base + (elt_size * (index + 1)),
|
| 35 | base + (elt_size * index),
|
| 36 | (nr_elts - index) * elt_size);
|
| 37 |
|
| 38 | memcpy_disk(base + (elt_size * index), elt, elt_size);
|
| 39 | }
|
| 40 |
|
| 41 |
|
| 42 |
|
| 43 |
|
| 44 | static int bsearch(struct btree_node *n, uint64_t key, int want_hi)
|
| 45 | {
|
| 46 | int lo = -1, hi = le32_to_cpu(n->header.nr_entries);
|
| 47 |
|
| 48 | while (hi - lo > 1) {
|
| 49 | int mid = lo + ((hi - lo) / 2);
|
| 50 | uint64_t mid_key = le64_to_cpu(n->keys[mid]);
|
| 51 |
|
| 52 | if (mid_key == key)
|
| 53 | return mid;
|
| 54 |
|
| 55 | if (mid_key < key)
|
| 56 | lo = mid;
|
| 57 | else
|
| 58 | hi = mid;
|
| 59 | }
|
| 60 |
|
| 61 | return want_hi ? hi : lo;
|
| 62 | }
|
| 63 |
|
| 64 | int lower_bound(struct btree_node *n, uint64_t key)
|
| 65 | {
|
| 66 | return bsearch(n, key, 0);
|
| 67 | }
|
| 68 |
|
| 69 | static int upper_bound(struct btree_node *n, uint64_t key)
|
| 70 | {
|
| 71 | return bsearch(n, key, 1);
|
| 72 | }
|
| 73 |
|
| 74 | void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
|
| 75 | struct dm_btree_value_type *vt)
|
| 76 | {
|
| 77 | uint32_t nr_entries = le32_to_cpu(n->header.nr_entries);
|
| 78 |
|
| 79 | if (le32_to_cpu(n->header.flags) & INTERNAL_NODE)
|
| 80 | dm_tm_with_runs(tm, value_ptr(n, 0), nr_entries, dm_tm_inc_range);
|
| 81 |
|
| 82 | else if (vt->inc)
|
| 83 | vt->inc(vt->context, value_ptr(n, 0), nr_entries);
|
| 84 | }
|
| 85 |
|
| 86 | static int insert_at(size_t value_size, struct btree_node *node, unsigned int index,
|
| 87 | uint64_t key, void *value)
|
| 88 | __dm_written_to_disk(value)
|
| 89 | {
|
| 90 | uint32_t nr_entries = le32_to_cpu(node->header.nr_entries);
|
| 91 | uint32_t max_entries = le32_to_cpu(node->header.max_entries);
|
| 92 | __le64 key_le = cpu_to_le64(key);
|
| 93 |
|
| 94 | if (index > nr_entries ||
|
| 95 | index >= max_entries ||
|
| 96 | nr_entries >= max_entries) {
|
| 97 | DMERR("too many entries in btree node for insert");
|
| 98 | __dm_unbless_for_disk(value);
|
| 99 | return -ENOMEM;
|
| 100 | }
|
| 101 |
|
| 102 | __dm_bless_for_disk(&key_le);
|
| 103 |
|
| 104 | array_insert(node->keys, sizeof(*node->keys), nr_entries, index, &key_le);
|
| 105 | array_insert(value_base(node), value_size, nr_entries, index, value);
|
| 106 | node->header.nr_entries = cpu_to_le32(nr_entries + 1);
|
| 107 |
|
| 108 | return 0;
|
| 109 | }
|
| 110 |
|
| 111 |
|
| 112 |
|
| 113 | |
| 114 | * We want 3n entries (for some n). This works more nicely for repeated
|
| 115 | * insert remove loops than (2n + 1).
|
| 116 |
|
| 117 | static uint32_t calc_max_entries(size_t value_size, size_t block_size)
|
| 118 | {
|
| 119 | uint32_t total, n;
|
| 120 | size_t elt_size = sizeof(uint64_t) + value_size;
|
| 121 |
|
| 122 | block_size -= sizeof(struct node_header);
|
| 123 | total = block_size / elt_size;
|
| 124 | n = total / 3;
|
| 125 |
|
| 126 | return 3 * n;
|
| 127 | }
|
| 128 |
|
| 129 | int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root)
|
| 130 | {
|
| 131 | int r;
|
| 132 | struct dm_block *b;
|
| 133 | struct btree_node *n;
|
| 134 | size_t block_size;
|
| 135 | uint32_t max_entries;
|
| 136 |
|
| 137 | r = new_block(info, &b);
|
| 138 | if (r < 0)
|
| 139 | return r;
|
| 140 |
|
| 141 | block_size = dm_bm_block_size(dm_tm_get_bm(info->tm));
|
| 142 | max_entries = calc_max_entries(info->value_type.size, block_size);
|
| 143 |
|
| 144 | n = dm_block_data(b);
|
| 145 | memset(n, 0, block_size);
|
| 146 | n->header.flags = cpu_to_le32(LEAF_NODE);
|
| 147 | n->header.nr_entries = cpu_to_le32(0);
|
| 148 | n->header.max_entries = cpu_to_le32(max_entries);
|
| 149 | n->header.value_size = cpu_to_le32(info->value_type.size);
|
| 150 |
|
| 151 | *root = dm_block_location(b);
|
| 152 | unlock_block(info, b);
|
| 153 |
|
| 154 | return 0;
|
| 155 | }
|
| 156 | EXPORT_SYMBOL_GPL(dm_btree_empty);
|
| 157 |
|
| 158 |
|
| 159 |
|
| 160 | |
| 161 | * Deletion uses a recursive algorithm, since we have limited stack space
|
| 162 | * we explicitly manage our own stack on the heap.
|
| 163 |
|
| 164 | #define MAX_SPINE_DEPTH 64
|
| 165 | struct frame {
|
| 166 | struct dm_block *b;
|
| 167 | struct btree_node *n;
|
| 168 | unsigned int level;
|
| 169 | unsigned int nr_children;
|
| 170 | unsigned int current_child;
|
| 171 | };
|
| 172 |
|
| 173 | struct del_stack {
|
| 174 | struct dm_btree_info *info;
|
| 175 | struct dm_transaction_manager *tm;
|
| 176 | int top;
|
| 177 | struct frame spine[MAX_SPINE_DEPTH];
|
| 178 | };
|
| 179 |
|
| 180 | static int top_frame(struct del_stack *s, struct frame **f)
|
| 181 | {
|
| 182 | if (s->top < 0) {
|
| 183 | DMERR("btree deletion stack empty");
|
| 184 | return -EINVAL;
|
| 185 | }
|
| 186 |
|
| 187 | *f = s->spine + s->top;
|
| 188 |
|
| 189 | return 0;
|
| 190 | }
|
| 191 |
|
| 192 | static int unprocessed_frames(struct del_stack *s)
|
| 193 | {
|
| 194 | return s->top >= 0;
|
| 195 | }
|
| 196 |
|
| 197 | static void prefetch_children(struct del_stack *s, struct frame *f)
|
| 198 | {
|
| 199 | unsigned int i;
|
| 200 | struct dm_block_manager *bm = dm_tm_get_bm(s->tm);
|
| 201 |
|
| 202 | for (i = 0; i < f->nr_children; i++)
|
| 203 | dm_bm_prefetch(bm, value64(f->n, i));
|
| 204 | }
|
| 205 |
|
| 206 | static bool is_internal_level(struct dm_btree_info *info, struct frame *f)
|
| 207 | {
|
| 208 | return f->level < (info->levels - 1);
|
| 209 | }
|
| 210 |
|
| 211 | static int push_frame(struct del_stack *s, dm_block_t b, unsigned int level)
|
| 212 | {
|
| 213 | int r;
|
| 214 | uint32_t ref_count;
|
| 215 |
|
| 216 | if (s->top >= MAX_SPINE_DEPTH - 1) {
|
| 217 | DMERR("btree deletion stack out of memory");
|
| 218 | return -ENOMEM;
|
| 219 | }
|
| 220 |
|
| 221 | r = dm_tm_ref(s->tm, b, &ref_count);
|
| 222 | if (r)
|
| 223 | return r;
|
| 224 |
|
| 225 | if (ref_count > 1)
|
| 226 | |
| 227 | * This is a shared node, so we can just decrement it's
|
| 228 | * reference counter and leave the children.
|
| 229 |
|
| 230 | dm_tm_dec(s->tm, b);
|
| 231 |
|
| 232 | else {
|
| 233 | uint32_t flags;
|
| 234 | struct frame *f = s->spine + ++s->top;
|
| 235 |
|
| 236 | r = dm_tm_read_lock(s->tm, b, &btree_node_validator, &f->b);
|
| 237 | if (r) {
|
| 238 | s->top--;
|
| 239 | return r;
|
| 240 | }
|
| 241 |
|
| 242 | f->n = dm_block_data(f->b);
|
| 243 | f->level = level;
|
| 244 | f->nr_children = le32_to_cpu(f->n->header.nr_entries);
|
| 245 | f->current_child = 0;
|
| 246 |
|
| 247 | flags = le32_to_cpu(f->n->header.flags);
|
| 248 | if (flags & INTERNAL_NODE || is_internal_level(s->info, f))
|
| 249 | prefetch_children(s, f);
|
| 250 | }
|
| 251 |
|
| 252 | return 0;
|
| 253 | }
|
| 254 |
|
| 255 | static void pop_frame(struct del_stack *s)
|
| 256 | {
|
| 257 | struct frame *f = s->spine + s->top--;
|
| 258 |
|
| 259 | dm_tm_dec(s->tm, dm_block_location(f->b));
|
| 260 | dm_tm_unlock(s->tm, f->b);
|
| 261 | }
|
| 262 |
|
| 263 | static void unlock_all_frames(struct del_stack *s)
|
| 264 | {
|
| 265 | struct frame *f;
|
| 266 |
|
| 267 | while (unprocessed_frames(s)) {
|
| 268 | f = s->spine + s->top--;
|
| 269 | dm_tm_unlock(s->tm, f->b);
|
| 270 | }
|
| 271 | }
|
| 272 |
|
| 273 | int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
|
| 274 | {
|
| 275 | int r;
|
| 276 | struct del_stack *s;
|
| 277 |
|
| 278 | |
| 279 | * dm_btree_del() is called via an ioctl, as such should be
|
| 280 | * considered an FS op. We can't recurse back into the FS, so we
|
| 281 | * allocate GFP_NOFS.
|
| 282 |
|
| 283 | s = kmalloc_obj(*s, GFP_NOFS);
|
| 284 | if (!s)
|
| 285 | return -ENOMEM;
|
| 286 | s->info = info;
|
| 287 | s->tm = info->tm;
|
| 288 | s->top = -1;
|
| 289 |
|
| 290 | r = push_frame(s, root, 0);
|
| 291 | if (r)
|
| 292 | goto out;
|
| 293 |
|
| 294 | while (unprocessed_frames(s)) {
|
| 295 | uint32_t flags;
|
| 296 | struct frame *f;
|
| 297 | dm_block_t b;
|
| 298 |
|
| 299 | r = top_frame(s, &f);
|
| 300 | if (r)
|
| 301 | goto out;
|
| 302 |
|
| 303 | if (f->current_child >= f->nr_children) {
|
| 304 | pop_frame(s);
|
| 305 | continue;
|
| 306 | }
|
| 307 |
|
| 308 | flags = le32_to_cpu(f->n->header.flags);
|
| 309 | if (flags & INTERNAL_NODE) {
|
| 310 | b = value64(f->n, f->current_child);
|
| 311 | f->current_child++;
|
| 312 | r = push_frame(s, b, f->level);
|
| 313 | if (r)
|
| 314 | goto out;
|
| 315 |
|
| 316 | } else if (is_internal_level(info, f)) {
|
| 317 | b = value64(f->n, f->current_child);
|
| 318 | f->current_child++;
|
| 319 | r = push_frame(s, b, f->level + 1);
|
| 320 | if (r)
|
| 321 | goto out;
|
| 322 |
|
| 323 | } else {
|
| 324 | if (info->value_type.dec)
|
| 325 | info->value_type.dec(info->value_type.context,
|
| 326 | value_ptr(f->n, 0), f->nr_children);
|
| 327 | pop_frame(s);
|
| 328 | }
|
| 329 | }
|
| 330 | out:
|
| 331 | if (r) {
|
| 332 |
|
| 333 | unlock_all_frames(s);
|
| 334 | }
|
| 335 | kfree(s);
|
| 336 |
|
| 337 | return r;
|
| 338 | }
|
| 339 | EXPORT_SYMBOL_GPL(dm_btree_del);
|
| 340 |
|
| 341 |
|
| 342 |
|
| 343 | static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key,
|
| 344 | int (*search_fn)(struct btree_node *, uint64_t),
|
| 345 | uint64_t *result_key, void *v, size_t value_size)
|
| 346 | {
|
| 347 | int i, r;
|
| 348 | uint32_t flags, nr_entries;
|
| 349 |
|
| 350 | do {
|
| 351 | r = ro_step(s, block);
|
| 352 | if (r < 0)
|
| 353 | return r;
|
| 354 |
|
| 355 | i = search_fn(ro_node(s), key);
|
| 356 |
|
| 357 | flags = le32_to_cpu(ro_node(s)->header.flags);
|
| 358 | nr_entries = le32_to_cpu(ro_node(s)->header.nr_entries);
|
| 359 | if (i < 0 || i >= nr_entries)
|
| 360 | return -ENODATA;
|
| 361 |
|
| 362 | if (flags & INTERNAL_NODE)
|
| 363 | block = value64(ro_node(s), i);
|
| 364 |
|
| 365 | } while (!(flags & LEAF_NODE));
|
| 366 |
|
| 367 | *result_key = le64_to_cpu(ro_node(s)->keys[i]);
|
| 368 | if (v)
|
| 369 | memcpy(v, value_ptr(ro_node(s), i), value_size);
|
| 370 |
|
| 371 | return 0;
|
| 372 | }
|
| 373 |
|
| 374 | int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
|
| 375 | uint64_t *keys, void *value_le)
|
| 376 | {
|
| 377 | unsigned int level, last_level = info->levels - 1;
|
| 378 | int r = -ENODATA;
|
| 379 | uint64_t rkey;
|
| 380 | __le64 internal_value_le;
|
| 381 | struct ro_spine spine;
|
| 382 |
|
| 383 | init_ro_spine(&spine, info);
|
| 384 | for (level = 0; level < info->levels; level++) {
|
| 385 | size_t size;
|
| 386 | void *value_p;
|
| 387 |
|
| 388 | if (level == last_level) {
|
| 389 | value_p = value_le;
|
| 390 | size = info->value_type.size;
|
| 391 |
|
| 392 | } else {
|
| 393 | value_p = &internal_value_le;
|
| 394 | size = sizeof(uint64_t);
|
| 395 | }
|
| 396 |
|
| 397 | r = btree_lookup_raw(&spine, root, keys[level],
|
| 398 | lower_bound, &rkey,
|
| 399 | value_p, size);
|
| 400 |
|
| 401 | if (!r) {
|
| 402 | if (rkey != keys[level]) {
|
| 403 | exit_ro_spine(&spine);
|
| 404 | return -ENODATA;
|
| 405 | }
|
| 406 | } else {
|
| 407 | exit_ro_spine(&spine);
|
| 408 | return r;
|
| 409 | }
|
| 410 |
|
| 411 | root = le64_to_cpu(internal_value_le);
|
| 412 | }
|
| 413 | exit_ro_spine(&spine);
|
| 414 |
|
| 415 | return r;
|
| 416 | }
|
| 417 | EXPORT_SYMBOL_GPL(dm_btree_lookup);
|
| 418 |
|
| 419 | static int dm_btree_lookup_next_single(struct dm_btree_info *info, dm_block_t root,
|
| 420 | uint64_t key, uint64_t *rkey, void *value_le)
|
| 421 | {
|
| 422 | int r, i;
|
| 423 | uint32_t flags, nr_entries;
|
| 424 | struct dm_block *node;
|
| 425 | struct btree_node *n;
|
| 426 |
|
| 427 | r = bn_read_lock(info, root, &node);
|
| 428 | if (r)
|
| 429 | return r;
|
| 430 |
|
| 431 | n = dm_block_data(node);
|
| 432 | flags = le32_to_cpu(n->header.flags);
|
| 433 | nr_entries = le32_to_cpu(n->header.nr_entries);
|
| 434 |
|
| 435 | if (flags & INTERNAL_NODE) {
|
| 436 | i = lower_bound(n, key);
|
| 437 | if (i < 0) {
|
| 438 | |
| 439 | * avoid early -ENODATA return when all entries are
|
| 440 | * higher than the search @key.
|
| 441 |
|
| 442 | i = 0;
|
| 443 | }
|
| 444 | if (i >= nr_entries) {
|
| 445 | r = -ENODATA;
|
| 446 | goto out;
|
| 447 | }
|
| 448 |
|
| 449 | r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);
|
| 450 | if (r == -ENODATA && i < (nr_entries - 1)) {
|
| 451 | i++;
|
| 452 | r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);
|
| 453 | }
|
| 454 |
|
| 455 | } else {
|
| 456 | i = upper_bound(n, key);
|
| 457 | if (i < 0 || i >= nr_entries) {
|
| 458 | r = -ENODATA;
|
| 459 | goto out;
|
| 460 | }
|
| 461 |
|
| 462 | *rkey = le64_to_cpu(n->keys[i]);
|
| 463 | memcpy(value_le, value_ptr(n, i), info->value_type.size);
|
| 464 | }
|
| 465 | out:
|
| 466 | dm_tm_unlock(info->tm, node);
|
| 467 | return r;
|
| 468 | }
|
| 469 |
|
| 470 | int dm_btree_lookup_next(struct dm_btree_info *info, dm_block_t root,
|
| 471 | uint64_t *keys, uint64_t *rkey, void *value_le)
|
| 472 | {
|
| 473 | unsigned int level;
|
| 474 | int r = -ENODATA;
|
| 475 | __le64 internal_value_le;
|
| 476 | struct ro_spine spine;
|
| 477 |
|
| 478 | init_ro_spine(&spine, info);
|
| 479 | for (level = 0; level < info->levels - 1u; level++) {
|
| 480 | r = btree_lookup_raw(&spine, root, keys[level],
|
| 481 | lower_bound, rkey,
|
| 482 | &internal_value_le, sizeof(uint64_t));
|
| 483 | if (r)
|
| 484 | goto out;
|
| 485 |
|
| 486 | if (*rkey != keys[level]) {
|
| 487 | r = -ENODATA;
|
| 488 | goto out;
|
| 489 | }
|
| 490 |
|
| 491 | root = le64_to_cpu(internal_value_le);
|
| 492 | }
|
| 493 |
|
| 494 | r = dm_btree_lookup_next_single(info, root, keys[level], rkey, value_le);
|
| 495 | out:
|
| 496 | exit_ro_spine(&spine);
|
| 497 | return r;
|
| 498 | }
|
| 499 | EXPORT_SYMBOL_GPL(dm_btree_lookup_next);
|
| 500 |
|
| 501 |
|
| 502 |
|
| 503 | |
| 504 | * Copies entries from one region of a btree node to another. The regions
|
| 505 | * must not overlap.
|
| 506 |
|
| 507 | static void copy_entries(struct btree_node *dest, unsigned int dest_offset,
|
| 508 | struct btree_node *src, unsigned int src_offset,
|
| 509 | unsigned int count)
|
| 510 | {
|
| 511 | size_t value_size = le32_to_cpu(dest->header.value_size);
|
| 512 |
|
| 513 | memcpy(dest->keys + dest_offset, src->keys + src_offset, count * sizeof(uint64_t));
|
| 514 | memcpy(value_ptr(dest, dest_offset), value_ptr(src, src_offset), count * value_size);
|
| 515 | }
|
| 516 |
|
| 517 | |
| 518 | * Moves entries from one region fo a btree node to another. The regions
|
| 519 | * may overlap.
|
| 520 |
|
| 521 | static void move_entries(struct btree_node *dest, unsigned int dest_offset,
|
| 522 | struct btree_node *src, unsigned int src_offset,
|
| 523 | unsigned int count)
|
| 524 | {
|
| 525 | size_t value_size = le32_to_cpu(dest->header.value_size);
|
| 526 |
|
| 527 | memmove(dest->keys + dest_offset, src->keys + src_offset, count * sizeof(uint64_t));
|
| 528 | memmove(value_ptr(dest, dest_offset), value_ptr(src, src_offset), count * value_size);
|
| 529 | }
|
| 530 |
|
| 531 | |
| 532 | * Erases the first 'count' entries of a btree node, shifting following
|
| 533 | * entries down into their place.
|
| 534 |
|
| 535 | static void shift_down(struct btree_node *n, unsigned int count)
|
| 536 | {
|
| 537 | move_entries(n, 0, n, count, le32_to_cpu(n->header.nr_entries) - count);
|
| 538 | }
|
| 539 |
|
| 540 | |
| 541 | * Moves entries in a btree node up 'count' places, making space for
|
| 542 | * new entries at the start of the node.
|
| 543 |
|
| 544 | static void shift_up(struct btree_node *n, unsigned int count)
|
| 545 | {
|
| 546 | move_entries(n, count, n, 0, le32_to_cpu(n->header.nr_entries));
|
| 547 | }
|
| 548 |
|
| 549 | |
| 550 | * Redistributes entries between two btree nodes to make them
|
| 551 | * have similar numbers of entries.
|
| 552 |
|
| 553 | static void redistribute2(struct btree_node *left, struct btree_node *right)
|
| 554 | {
|
| 555 | unsigned int nr_left = le32_to_cpu(left->header.nr_entries);
|
| 556 | unsigned int nr_right = le32_to_cpu(right->header.nr_entries);
|
| 557 | unsigned int total = nr_left + nr_right;
|
| 558 | unsigned int target_left = total / 2;
|
| 559 | unsigned int target_right = total - target_left;
|
| 560 |
|
| 561 | if (nr_left < target_left) {
|
| 562 | unsigned int delta = target_left - nr_left;
|
| 563 |
|
| 564 | copy_entries(left, nr_left, right, 0, delta);
|
| 565 | shift_down(right, delta);
|
| 566 | } else if (nr_left > target_left) {
|
| 567 | unsigned int delta = nr_left - target_left;
|
| 568 |
|
| 569 | if (nr_right)
|
| 570 | shift_up(right, delta);
|
| 571 | copy_entries(right, 0, left, target_left, delta);
|
| 572 | }
|
| 573 |
|
| 574 | left->header.nr_entries = cpu_to_le32(target_left);
|
| 575 | right->header.nr_entries = cpu_to_le32(target_right);
|
| 576 | }
|
| 577 |
|
| 578 | |
| 579 | * Redistribute entries between three nodes. Assumes the central
|
| 580 | * node is empty.
|
| 581 |
|
| 582 | static void redistribute3(struct btree_node *left, struct btree_node *center,
|
| 583 | struct btree_node *right)
|
| 584 | {
|
| 585 | unsigned int nr_left = le32_to_cpu(left->header.nr_entries);
|
| 586 | unsigned int nr_center = le32_to_cpu(center->header.nr_entries);
|
| 587 | unsigned int nr_right = le32_to_cpu(right->header.nr_entries);
|
| 588 | unsigned int total, target_left, target_center, target_right;
|
| 589 |
|
| 590 | BUG_ON(nr_center);
|
| 591 |
|
| 592 | total = nr_left + nr_right;
|
| 593 | target_left = total / 3;
|
| 594 | target_center = (total - target_left) / 2;
|
| 595 | target_right = (total - target_left - target_center);
|
| 596 |
|
| 597 | if (nr_left < target_left) {
|
| 598 | unsigned int left_short = target_left - nr_left;
|
| 599 |
|
| 600 | copy_entries(left, nr_left, right, 0, left_short);
|
| 601 | copy_entries(center, 0, right, left_short, target_center);
|
| 602 | shift_down(right, nr_right - target_right);
|
| 603 |
|
| 604 | } else if (nr_left < (target_left + target_center)) {
|
| 605 | unsigned int left_to_center = nr_left - target_left;
|
| 606 |
|
| 607 | copy_entries(center, 0, left, target_left, left_to_center);
|
| 608 | copy_entries(center, left_to_center, right, 0, target_center - left_to_center);
|
| 609 | shift_down(right, nr_right - target_right);
|
| 610 |
|
| 611 | } else {
|
| 612 | unsigned int right_short = target_right - nr_right;
|
| 613 |
|
| 614 | shift_up(right, right_short);
|
| 615 | copy_entries(right, 0, left, nr_left - right_short, right_short);
|
| 616 | copy_entries(center, 0, left, target_left, nr_left - target_left);
|
| 617 | }
|
| 618 |
|
| 619 | left->header.nr_entries = cpu_to_le32(target_left);
|
| 620 | center->header.nr_entries = cpu_to_le32(target_center);
|
| 621 | right->header.nr_entries = cpu_to_le32(target_right);
|
| 622 | }
|
| 623 |
|
| 624 | |
| 625 | * Splits a node by creating a sibling node and shifting half the nodes
|
| 626 | * contents across. Assumes there is a parent node, and it has room for
|
| 627 | * another child.
|
| 628 | *
|
| 629 | * Before:
|
| 630 | * +--------+
|
| 631 | * | Parent |
|
| 632 | * +--------+
|
| 633 | * |
|
| 634 | * v
|
| 635 | * +----------+
|
| 636 | * | A ++++++ |
|
| 637 | * +----------+
|
| 638 | *
|
| 639 | *
|
| 640 | * After:
|
| 641 | * +--------+
|
| 642 | * | Parent |
|
| 643 | * +--------+
|
| 644 | * | |
|
| 645 | * v +------+
|
| 646 | * +---------+ |
|
| 647 | * | A* +++ | v
|
| 648 | * +---------+ +-------+
|
| 649 | * | B +++ |
|
| 650 | * +-------+
|
| 651 | *
|
| 652 | * Where A* is a shadow of A.
|
| 653 |
|
| 654 | static int split_one_into_two(struct shadow_spine *s, unsigned int parent_index,
|
| 655 | struct dm_btree_value_type *vt, uint64_t key)
|
| 656 | {
|
| 657 | int r;
|
| 658 | struct dm_block *left, *right, *parent;
|
| 659 | struct btree_node *ln, *rn, *pn;
|
| 660 | __le64 location;
|
| 661 |
|
| 662 | left = shadow_current(s);
|
| 663 |
|
| 664 | r = new_block(s->info, &right);
|
| 665 | if (r < 0)
|
| 666 | return r;
|
| 667 |
|
| 668 | ln = dm_block_data(left);
|
| 669 | rn = dm_block_data(right);
|
| 670 |
|
| 671 | rn->header.flags = ln->header.flags;
|
| 672 | rn->header.nr_entries = cpu_to_le32(0);
|
| 673 | rn->header.max_entries = ln->header.max_entries;
|
| 674 | rn->header.value_size = ln->header.value_size;
|
| 675 | redistribute2(ln, rn);
|
| 676 |
|
| 677 |
|
| 678 | parent = shadow_parent(s);
|
| 679 | pn = dm_block_data(parent);
|
| 680 |
|
| 681 | location = cpu_to_le64(dm_block_location(right));
|
| 682 | __dm_bless_for_disk(&location);
|
| 683 | r = insert_at(sizeof(__le64), pn, parent_index + 1,
|
| 684 | le64_to_cpu(rn->keys[0]), &location);
|
| 685 | if (r) {
|
| 686 | unlock_block(s->info, right);
|
| 687 | return r;
|
| 688 | }
|
| 689 |
|
| 690 |
|
| 691 | if (key < le64_to_cpu(rn->keys[0])) {
|
| 692 | unlock_block(s->info, right);
|
| 693 | s->nodes[1] = left;
|
| 694 | } else {
|
| 695 | unlock_block(s->info, left);
|
| 696 | s->nodes[1] = right;
|
| 697 | }
|
| 698 |
|
| 699 | return 0;
|
| 700 | }
|
| 701 |
|
| 702 | |
| 703 | * We often need to modify a sibling node. This function shadows a particular
|
| 704 | * child of the given parent node. Making sure to update the parent to point
|
| 705 | * to the new shadow.
|
| 706 |
|
| 707 | static int shadow_child(struct dm_btree_info *info, struct dm_btree_value_type *vt,
|
| 708 | struct btree_node *parent, unsigned int index,
|
| 709 | struct dm_block **result)
|
| 710 | {
|
| 711 | int r, inc;
|
| 712 | dm_block_t root;
|
| 713 | struct btree_node *node;
|
| 714 |
|
| 715 | root = value64(parent, index);
|
| 716 |
|
| 717 | r = dm_tm_shadow_block(info->tm, root, &btree_node_validator,
|
| 718 | result, &inc);
|
| 719 | if (r)
|
| 720 | return r;
|
| 721 |
|
| 722 | node = dm_block_data(*result);
|
| 723 |
|
| 724 | if (inc)
|
| 725 | inc_children(info->tm, node, vt);
|
| 726 |
|
| 727 | *((__le64 *) value_ptr(parent, index)) =
|
| 728 | cpu_to_le64(dm_block_location(*result));
|
| 729 |
|
| 730 | return 0;
|
| 731 | }
|
| 732 |
|
| 733 | |
| 734 | * Splits two nodes into three. This is more work, but results in fuller
|
| 735 | * nodes, so saves metadata space.
|
| 736 |
|
| 737 | static int split_two_into_three(struct shadow_spine *s, unsigned int parent_index,
|
| 738 | struct dm_btree_value_type *vt, uint64_t key)
|
| 739 | {
|
| 740 | int r;
|
| 741 | unsigned int middle_index;
|
| 742 | struct dm_block *left, *middle, *right, *parent;
|
| 743 | struct btree_node *ln, *rn, *mn, *pn;
|
| 744 | __le64 location;
|
| 745 |
|
| 746 | parent = shadow_parent(s);
|
| 747 | pn = dm_block_data(parent);
|
| 748 |
|
| 749 | if (parent_index == 0) {
|
| 750 | middle_index = 1;
|
| 751 | left = shadow_current(s);
|
| 752 | r = shadow_child(s->info, vt, pn, parent_index + 1, &right);
|
| 753 | if (r)
|
| 754 | return r;
|
| 755 | } else {
|
| 756 | middle_index = parent_index;
|
| 757 | right = shadow_current(s);
|
| 758 | r = shadow_child(s->info, vt, pn, parent_index - 1, &left);
|
| 759 | if (r)
|
| 760 | return r;
|
| 761 | }
|
| 762 |
|
| 763 | r = new_block(s->info, &middle);
|
| 764 | if (r < 0)
|
| 765 | return r;
|
| 766 |
|
| 767 | ln = dm_block_data(left);
|
| 768 | mn = dm_block_data(middle);
|
| 769 | rn = dm_block_data(right);
|
| 770 |
|
| 771 | mn->header.nr_entries = cpu_to_le32(0);
|
| 772 | mn->header.flags = ln->header.flags;
|
| 773 | mn->header.max_entries = ln->header.max_entries;
|
| 774 | mn->header.value_size = ln->header.value_size;
|
| 775 |
|
| 776 | redistribute3(ln, mn, rn);
|
| 777 |
|
| 778 |
|
| 779 | pn->keys[middle_index] = rn->keys[0];
|
| 780 | location = cpu_to_le64(dm_block_location(middle));
|
| 781 | __dm_bless_for_disk(&location);
|
| 782 | r = insert_at(sizeof(__le64), pn, middle_index,
|
| 783 | le64_to_cpu(mn->keys[0]), &location);
|
| 784 | if (r) {
|
| 785 | if (shadow_current(s) != left)
|
| 786 | unlock_block(s->info, left);
|
| 787 |
|
| 788 | unlock_block(s->info, middle);
|
| 789 |
|
| 790 | if (shadow_current(s) != right)
|
| 791 | unlock_block(s->info, right);
|
| 792 |
|
| 793 | return r;
|
| 794 | }
|
| 795 |
|
| 796 |
|
| 797 |
|
| 798 | if (key < le64_to_cpu(mn->keys[0])) {
|
| 799 | unlock_block(s->info, middle);
|
| 800 | unlock_block(s->info, right);
|
| 801 | s->nodes[1] = left;
|
| 802 | } else if (key < le64_to_cpu(rn->keys[0])) {
|
| 803 | unlock_block(s->info, left);
|
| 804 | unlock_block(s->info, right);
|
| 805 | s->nodes[1] = middle;
|
| 806 | } else {
|
| 807 | unlock_block(s->info, left);
|
| 808 | unlock_block(s->info, middle);
|
| 809 | s->nodes[1] = right;
|
| 810 | }
|
| 811 |
|
| 812 | return 0;
|
| 813 | }
|
| 814 |
|
| 815 |
|
| 816 |
|
| 817 | |
| 818 | * Splits a node by creating two new children beneath the given node.
|
| 819 | *
|
| 820 | * Before:
|
| 821 | * +----------+
|
| 822 | * | A ++++++ |
|
| 823 | * +----------+
|
| 824 | *
|
| 825 | *
|
| 826 | * After:
|
| 827 | * +------------+
|
| 828 | * | A (shadow) |
|
| 829 | * +------------+
|
| 830 | * | |
|
| 831 | * +------+ +----+
|
| 832 | * | |
|
| 833 | * v v
|
| 834 | * +-------+ +-------+
|
| 835 | * | B +++ | | C +++ |
|
| 836 | * +-------+ +-------+
|
| 837 |
|
| 838 | static int btree_split_beneath(struct shadow_spine *s, uint64_t key)
|
| 839 | {
|
| 840 | int r;
|
| 841 | size_t size;
|
| 842 | unsigned int nr_left, nr_right;
|
| 843 | struct dm_block *left, *right, *new_parent;
|
| 844 | struct btree_node *pn, *ln, *rn;
|
| 845 | __le64 val;
|
| 846 |
|
| 847 | new_parent = shadow_current(s);
|
| 848 |
|
| 849 | pn = dm_block_data(new_parent);
|
| 850 | size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ?
|
| 851 | sizeof(__le64) : s->info->value_type.size;
|
| 852 |
|
| 853 |
|
| 854 | r = new_block(s->info, &left);
|
| 855 | if (r < 0)
|
| 856 | return r;
|
| 857 |
|
| 858 | ln = dm_block_data(left);
|
| 859 | nr_left = le32_to_cpu(pn->header.nr_entries) / 2;
|
| 860 |
|
| 861 | ln->header.flags = pn->header.flags;
|
| 862 | ln->header.nr_entries = cpu_to_le32(nr_left);
|
| 863 | ln->header.max_entries = pn->header.max_entries;
|
| 864 | ln->header.value_size = pn->header.value_size;
|
| 865 | memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0]));
|
| 866 | memcpy(value_ptr(ln, 0), value_ptr(pn, 0), nr_left * size);
|
| 867 |
|
| 868 |
|
| 869 | r = new_block(s->info, &right);
|
| 870 | if (r < 0) {
|
| 871 | unlock_block(s->info, left);
|
| 872 | return r;
|
| 873 | }
|
| 874 |
|
| 875 | rn = dm_block_data(right);
|
| 876 | nr_right = le32_to_cpu(pn->header.nr_entries) - nr_left;
|
| 877 |
|
| 878 | rn->header.flags = pn->header.flags;
|
| 879 | rn->header.nr_entries = cpu_to_le32(nr_right);
|
| 880 | rn->header.max_entries = pn->header.max_entries;
|
| 881 | rn->header.value_size = pn->header.value_size;
|
| 882 | memcpy(rn->keys, pn->keys + nr_left, nr_right * sizeof(pn->keys[0]));
|
| 883 | memcpy(value_ptr(rn, 0), value_ptr(pn, nr_left),
|
| 884 | nr_right * size);
|
| 885 |
|
| 886 |
|
| 887 | pn->header.flags = cpu_to_le32(INTERNAL_NODE);
|
| 888 | pn->header.nr_entries = cpu_to_le32(2);
|
| 889 | pn->header.max_entries = cpu_to_le32(
|
| 890 | calc_max_entries(sizeof(__le64),
|
| 891 | dm_bm_block_size(
|
| 892 | dm_tm_get_bm(s->info->tm))));
|
| 893 | pn->header.value_size = cpu_to_le32(sizeof(__le64));
|
| 894 |
|
| 895 | val = cpu_to_le64(dm_block_location(left));
|
| 896 | __dm_bless_for_disk(&val);
|
| 897 | pn->keys[0] = ln->keys[0];
|
| 898 | memcpy_disk(value_ptr(pn, 0), &val, sizeof(__le64));
|
| 899 |
|
| 900 | val = cpu_to_le64(dm_block_location(right));
|
| 901 | __dm_bless_for_disk(&val);
|
| 902 | pn->keys[1] = rn->keys[0];
|
| 903 | memcpy_disk(value_ptr(pn, 1), &val, sizeof(__le64));
|
| 904 |
|
| 905 | unlock_block(s->info, left);
|
| 906 | unlock_block(s->info, right);
|
| 907 | return 0;
|
| 908 | }
|
| 909 |
|
| 910 |
|
| 911 |
|
| 912 | |
| 913 | * Redistributes a node's entries with its left sibling.
|
| 914 |
|
| 915 | static int rebalance_left(struct shadow_spine *s, struct dm_btree_value_type *vt,
|
| 916 | unsigned int parent_index, uint64_t key)
|
| 917 | {
|
| 918 | int r;
|
| 919 | struct dm_block *sib;
|
| 920 | struct btree_node *left, *right, *parent = dm_block_data(shadow_parent(s));
|
| 921 |
|
| 922 | r = shadow_child(s->info, vt, parent, parent_index - 1, &sib);
|
| 923 | if (r)
|
| 924 | return r;
|
| 925 |
|
| 926 | left = dm_block_data(sib);
|
| 927 | right = dm_block_data(shadow_current(s));
|
| 928 | redistribute2(left, right);
|
| 929 | *key_ptr(parent, parent_index) = right->keys[0];
|
| 930 |
|
| 931 | if (key < le64_to_cpu(right->keys[0])) {
|
| 932 | unlock_block(s->info, s->nodes[1]);
|
| 933 | s->nodes[1] = sib;
|
| 934 | } else {
|
| 935 | unlock_block(s->info, sib);
|
| 936 | }
|
| 937 |
|
| 938 | return 0;
|
| 939 | }
|
| 940 |
|
| 941 | |
| 942 | * Redistributes a nodes entries with its right sibling.
|
| 943 |
|
| 944 | static int rebalance_right(struct shadow_spine *s, struct dm_btree_value_type *vt,
|
| 945 | unsigned int parent_index, uint64_t key)
|
| 946 | {
|
| 947 | int r;
|
| 948 | struct dm_block *sib;
|
| 949 | struct btree_node *left, *right, *parent = dm_block_data(shadow_parent(s));
|
| 950 |
|
| 951 | r = shadow_child(s->info, vt, parent, parent_index + 1, &sib);
|
| 952 | if (r)
|
| 953 | return r;
|
| 954 |
|
| 955 | left = dm_block_data(shadow_current(s));
|
| 956 | right = dm_block_data(sib);
|
| 957 | redistribute2(left, right);
|
| 958 | *key_ptr(parent, parent_index + 1) = right->keys[0];
|
| 959 |
|
| 960 | if (key < le64_to_cpu(right->keys[0])) {
|
| 961 | unlock_block(s->info, sib);
|
| 962 | } else {
|
| 963 | unlock_block(s->info, s->nodes[1]);
|
| 964 | s->nodes[1] = sib;
|
| 965 | }
|
| 966 |
|
| 967 | return 0;
|
| 968 | }
|
| 969 |
|
| 970 | |
| 971 | * Returns the number of spare entries in a node.
|
| 972 |
|
| 973 | static int get_node_free_space(struct dm_btree_info *info, dm_block_t b, unsigned int *space)
|
| 974 | {
|
| 975 | int r;
|
| 976 | unsigned int nr_entries;
|
| 977 | struct dm_block *block;
|
| 978 | struct btree_node *node;
|
| 979 |
|
| 980 | r = bn_read_lock(info, b, &block);
|
| 981 | if (r)
|
| 982 | return r;
|
| 983 |
|
| 984 | node = dm_block_data(block);
|
| 985 | nr_entries = le32_to_cpu(node->header.nr_entries);
|
| 986 | *space = le32_to_cpu(node->header.max_entries) - nr_entries;
|
| 987 |
|
| 988 | unlock_block(info, block);
|
| 989 | return 0;
|
| 990 | }
|
| 991 |
|
| 992 | |
| 993 | * Make space in a node, either by moving some entries to a sibling,
|
| 994 | * or creating a new sibling node. SPACE_THRESHOLD defines the minimum
|
| 995 | * number of free entries that must be in the sibling to make the move
|
| 996 | * worth while. If the siblings are shared (eg, part of a snapshot),
|
| 997 | * then they are not touched, since this break sharing and so consume
|
| 998 | * more space than we save.
|
| 999 |
|
| 1000 | #define SPACE_THRESHOLD 8
|
| 1001 | static int rebalance_or_split(struct shadow_spine *s, struct dm_btree_value_type *vt,
|
| 1002 | unsigned int parent_index, uint64_t key)
|
| 1003 | {
|
| 1004 | int r;
|
| 1005 | struct btree_node *parent = dm_block_data(shadow_parent(s));
|
| 1006 | unsigned int nr_parent = le32_to_cpu(parent->header.nr_entries);
|
| 1007 | unsigned int free_space;
|
| 1008 | int left_shared = 0, right_shared = 0;
|
| 1009 |
|
| 1010 |
|
| 1011 | if (parent_index > 0) {
|
| 1012 | dm_block_t left_b = value64(parent, parent_index - 1);
|
| 1013 |
|
| 1014 | r = dm_tm_block_is_shared(s->info->tm, left_b, &left_shared);
|
| 1015 | if (r)
|
| 1016 | return r;
|
| 1017 |
|
| 1018 | if (!left_shared) {
|
| 1019 | r = get_node_free_space(s->info, left_b, &free_space);
|
| 1020 | if (r)
|
| 1021 | return r;
|
| 1022 |
|
| 1023 | if (free_space >= SPACE_THRESHOLD)
|
| 1024 | return rebalance_left(s, vt, parent_index, key);
|
| 1025 | }
|
| 1026 | }
|
| 1027 |
|
| 1028 |
|
| 1029 | if (parent_index < (nr_parent - 1)) {
|
| 1030 | dm_block_t right_b = value64(parent, parent_index + 1);
|
| 1031 |
|
| 1032 | r = dm_tm_block_is_shared(s->info->tm, right_b, &right_shared);
|
| 1033 | if (r)
|
| 1034 | return r;
|
| 1035 |
|
| 1036 | if (!right_shared) {
|
| 1037 | r = get_node_free_space(s->info, right_b, &free_space);
|
| 1038 | if (r)
|
| 1039 | return r;
|
| 1040 |
|
| 1041 | if (free_space >= SPACE_THRESHOLD)
|
| 1042 | return rebalance_right(s, vt, parent_index, key);
|
| 1043 | }
|
| 1044 | }
|
| 1045 |
|
| 1046 | |
| 1047 | * We need to split the node, normally we split two nodes
|
| 1048 | * into three. But when inserting a sequence that is either
|
| 1049 | * monotonically increasing or decreasing it's better to split
|
| 1050 | * a single node into two.
|
| 1051 |
|
| 1052 | if (left_shared || right_shared || (nr_parent <= 2) ||
|
| 1053 | (parent_index == 0) || (parent_index + 1 == nr_parent)) {
|
| 1054 | return split_one_into_two(s, parent_index, vt, key);
|
| 1055 | } else {
|
| 1056 | return split_two_into_three(s, parent_index, vt, key);
|
| 1057 | }
|
| 1058 | }
|
| 1059 |
|
| 1060 | |
| 1061 | * Does the node contain a particular key?
|
| 1062 |
|
| 1063 | static bool contains_key(struct btree_node *node, uint64_t key)
|
| 1064 | {
|
| 1065 | int i = lower_bound(node, key);
|
| 1066 |
|
| 1067 | if (i >= 0 && le64_to_cpu(node->keys[i]) == key)
|
| 1068 | return true;
|
| 1069 |
|
| 1070 | return false;
|
| 1071 | }
|
| 1072 |
|
| 1073 | |
| 1074 | * In general we preemptively make sure there's a free entry in every
|
| 1075 | * node on the spine when doing an insert. But we can avoid that with
|
| 1076 | * leaf nodes if we know it's an overwrite.
|
| 1077 |
|
| 1078 | static bool has_space_for_insert(struct btree_node *node, uint64_t key)
|
| 1079 | {
|
| 1080 | if (node->header.nr_entries == node->header.max_entries) {
|
| 1081 | if (le32_to_cpu(node->header.flags) & LEAF_NODE) {
|
| 1082 |
|
| 1083 | return contains_key(node, key);
|
| 1084 | }
|
| 1085 |
|
| 1086 | return false;
|
| 1087 | }
|
| 1088 |
|
| 1089 | return true;
|
| 1090 | }
|
| 1091 |
|
| 1092 | static int btree_insert_raw(struct shadow_spine *s, dm_block_t root,
|
| 1093 | struct dm_btree_value_type *vt,
|
| 1094 | uint64_t key, unsigned int *index)
|
| 1095 | {
|
| 1096 | int r, i = *index, top = 1;
|
| 1097 | struct btree_node *node;
|
| 1098 |
|
| 1099 | for (;;) {
|
| 1100 | r = shadow_step(s, root, vt);
|
| 1101 | if (r < 0)
|
| 1102 | return r;
|
| 1103 |
|
| 1104 | node = dm_block_data(shadow_current(s));
|
| 1105 |
|
| 1106 | |
| 1107 | * We have to patch up the parent node, ugly, but I don't
|
| 1108 | * see a way to do this automatically as part of the spine
|
| 1109 | * op.
|
| 1110 |
|
| 1111 | if (shadow_has_parent(s) && i >= 0) {
|
| 1112 | __le64 location = cpu_to_le64(dm_block_location(shadow_current(s)));
|
| 1113 |
|
| 1114 | __dm_bless_for_disk(&location);
|
| 1115 | memcpy_disk(value_ptr(dm_block_data(shadow_parent(s)), i),
|
| 1116 | &location, sizeof(__le64));
|
| 1117 | }
|
| 1118 |
|
| 1119 | node = dm_block_data(shadow_current(s));
|
| 1120 |
|
| 1121 | if (!has_space_for_insert(node, key)) {
|
| 1122 | if (top)
|
| 1123 | r = btree_split_beneath(s, key);
|
| 1124 | else
|
| 1125 | r = rebalance_or_split(s, vt, i, key);
|
| 1126 |
|
| 1127 | if (r < 0)
|
| 1128 | return r;
|
| 1129 |
|
| 1130 |
|
| 1131 | node = dm_block_data(shadow_current(s));
|
| 1132 | }
|
| 1133 |
|
| 1134 | i = lower_bound(node, key);
|
| 1135 |
|
| 1136 | if (le32_to_cpu(node->header.flags) & LEAF_NODE)
|
| 1137 | break;
|
| 1138 |
|
| 1139 | if (i < 0) {
|
| 1140 |
|
| 1141 | node->keys[0] = cpu_to_le64(key);
|
| 1142 | i = 0;
|
| 1143 | }
|
| 1144 |
|
| 1145 | root = value64(node, i);
|
| 1146 | top = 0;
|
| 1147 | }
|
| 1148 |
|
| 1149 | if (i < 0 || le64_to_cpu(node->keys[i]) != key)
|
| 1150 | i++;
|
| 1151 |
|
| 1152 | *index = i;
|
| 1153 | return 0;
|
| 1154 | }
|
| 1155 |
|
| 1156 | static int __btree_get_overwrite_leaf(struct shadow_spine *s, dm_block_t root,
|
| 1157 | uint64_t key, int *index)
|
| 1158 | {
|
| 1159 | int r, i = -1;
|
| 1160 | struct btree_node *node;
|
| 1161 |
|
| 1162 | *index = 0;
|
| 1163 | for (;;) {
|
| 1164 | r = shadow_step(s, root, &s->info->value_type);
|
| 1165 | if (r < 0)
|
| 1166 | return r;
|
| 1167 |
|
| 1168 | node = dm_block_data(shadow_current(s));
|
| 1169 |
|
| 1170 | |
| 1171 | * We have to patch up the parent node, ugly, but I don't
|
| 1172 | * see a way to do this automatically as part of the spine
|
| 1173 | * op.
|
| 1174 |
|
| 1175 | if (shadow_has_parent(s) && i >= 0) {
|
| 1176 | __le64 location = cpu_to_le64(dm_block_location(shadow_current(s)));
|
| 1177 |
|
| 1178 | __dm_bless_for_disk(&location);
|
| 1179 | memcpy_disk(value_ptr(dm_block_data(shadow_parent(s)), i),
|
| 1180 | &location, sizeof(__le64));
|
| 1181 | }
|
| 1182 |
|
| 1183 | node = dm_block_data(shadow_current(s));
|
| 1184 | i = lower_bound(node, key);
|
| 1185 |
|
| 1186 | BUG_ON(i < 0);
|
| 1187 | BUG_ON(i >= le32_to_cpu(node->header.nr_entries));
|
| 1188 |
|
| 1189 | if (le32_to_cpu(node->header.flags) & LEAF_NODE) {
|
| 1190 | if (key != le64_to_cpu(node->keys[i]))
|
| 1191 | return -EINVAL;
|
| 1192 | break;
|
| 1193 | }
|
| 1194 |
|
| 1195 | root = value64(node, i);
|
| 1196 | }
|
| 1197 |
|
| 1198 | *index = i;
|
| 1199 | return 0;
|
| 1200 | }
|
| 1201 |
|
| 1202 | int btree_get_overwrite_leaf(struct dm_btree_info *info, dm_block_t root,
|
| 1203 | uint64_t key, int *index,
|
| 1204 | dm_block_t *new_root, struct dm_block **leaf)
|
| 1205 | {
|
| 1206 | int r;
|
| 1207 | struct shadow_spine spine;
|
| 1208 |
|
| 1209 | BUG_ON(info->levels > 1);
|
| 1210 | init_shadow_spine(&spine, info);
|
| 1211 | r = __btree_get_overwrite_leaf(&spine, root, key, index);
|
| 1212 | if (!r) {
|
| 1213 | *new_root = shadow_root(&spine);
|
| 1214 | *leaf = shadow_current(&spine);
|
| 1215 |
|
| 1216 | |
| 1217 | * Decrement the count so exit_shadow_spine() doesn't
|
| 1218 | * unlock the leaf.
|
| 1219 |
|
| 1220 | spine.count--;
|
| 1221 | }
|
| 1222 | exit_shadow_spine(&spine);
|
| 1223 |
|
| 1224 | return r;
|
| 1225 | }
|
| 1226 |
|
| 1227 | static bool need_insert(struct btree_node *node, uint64_t *keys,
|
| 1228 | unsigned int level, unsigned int index)
|
| 1229 | {
|
| 1230 | return ((index >= le32_to_cpu(node->header.nr_entries)) ||
|
| 1231 | (le64_to_cpu(node->keys[index]) != keys[level]));
|
| 1232 | }
|
| 1233 |
|
| 1234 | static int insert(struct dm_btree_info *info, dm_block_t root,
|
| 1235 | uint64_t *keys, void *value, dm_block_t *new_root,
|
| 1236 | int *inserted)
|
| 1237 | __dm_written_to_disk(value)
|
| 1238 | {
|
| 1239 | int r;
|
| 1240 | unsigned int level, index = -1, last_level = info->levels - 1;
|
| 1241 | dm_block_t block = root;
|
| 1242 | struct shadow_spine spine;
|
| 1243 | struct btree_node *n;
|
| 1244 | struct dm_btree_value_type le64_type;
|
| 1245 |
|
| 1246 | init_le64_type(info->tm, &le64_type);
|
| 1247 | init_shadow_spine(&spine, info);
|
| 1248 |
|
| 1249 | for (level = 0; level < (info->levels - 1); level++) {
|
| 1250 | r = btree_insert_raw(&spine, block, &le64_type, keys[level], &index);
|
| 1251 | if (r < 0)
|
| 1252 | goto bad;
|
| 1253 |
|
| 1254 | n = dm_block_data(shadow_current(&spine));
|
| 1255 |
|
| 1256 | if (need_insert(n, keys, level, index)) {
|
| 1257 | dm_block_t new_tree;
|
| 1258 | __le64 new_le;
|
| 1259 |
|
| 1260 | r = dm_btree_empty(info, &new_tree);
|
| 1261 | if (r < 0)
|
| 1262 | goto bad;
|
| 1263 |
|
| 1264 | new_le = cpu_to_le64(new_tree);
|
| 1265 | __dm_bless_for_disk(&new_le);
|
| 1266 |
|
| 1267 | r = insert_at(sizeof(uint64_t), n, index,
|
| 1268 | keys[level], &new_le);
|
| 1269 | if (r)
|
| 1270 | goto bad;
|
| 1271 | }
|
| 1272 |
|
| 1273 | if (level < last_level)
|
| 1274 | block = value64(n, index);
|
| 1275 | }
|
| 1276 |
|
| 1277 | r = btree_insert_raw(&spine, block, &info->value_type,
|
| 1278 | keys[level], &index);
|
| 1279 | if (r < 0)
|
| 1280 | goto bad;
|
| 1281 |
|
| 1282 | n = dm_block_data(shadow_current(&spine));
|
| 1283 |
|
| 1284 | if (need_insert(n, keys, level, index)) {
|
| 1285 | if (inserted)
|
| 1286 | *inserted = 1;
|
| 1287 |
|
| 1288 | r = insert_at(info->value_type.size, n, index,
|
| 1289 | keys[level], value);
|
| 1290 | if (r)
|
| 1291 | goto bad_unblessed;
|
| 1292 | } else {
|
| 1293 | if (inserted)
|
| 1294 | *inserted = 0;
|
| 1295 |
|
| 1296 | if (info->value_type.dec &&
|
| 1297 | (!info->value_type.equal ||
|
| 1298 | !info->value_type.equal(
|
| 1299 | info->value_type.context,
|
| 1300 | value_ptr(n, index),
|
| 1301 | value))) {
|
| 1302 | info->value_type.dec(info->value_type.context,
|
| 1303 | value_ptr(n, index), 1);
|
| 1304 | }
|
| 1305 | memcpy_disk(value_ptr(n, index),
|
| 1306 | value, info->value_type.size);
|
| 1307 | }
|
| 1308 |
|
| 1309 | *new_root = shadow_root(&spine);
|
| 1310 | exit_shadow_spine(&spine);
|
| 1311 |
|
| 1312 | return 0;
|
| 1313 |
|
| 1314 | bad:
|
| 1315 | __dm_unbless_for_disk(value);
|
| 1316 | bad_unblessed:
|
| 1317 | exit_shadow_spine(&spine);
|
| 1318 | return r;
|
| 1319 | }
|
| 1320 |
|
| 1321 | int dm_btree_insert(struct dm_btree_info *info, dm_block_t root,
|
| 1322 | uint64_t *keys, void *value, dm_block_t *new_root)
|
| 1323 | __dm_written_to_disk(value)
|
| 1324 | {
|
| 1325 | return insert(info, root, keys, value, new_root, NULL);
|
| 1326 | }
|
| 1327 | EXPORT_SYMBOL_GPL(dm_btree_insert);
|
| 1328 |
|
| 1329 | int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root,
|
| 1330 | uint64_t *keys, void *value, dm_block_t *new_root,
|
| 1331 | int *inserted)
|
| 1332 | __dm_written_to_disk(value)
|
| 1333 | {
|
| 1334 | return insert(info, root, keys, value, new_root, inserted);
|
| 1335 | }
|
| 1336 | EXPORT_SYMBOL_GPL(dm_btree_insert_notify);
|
| 1337 |
|
| 1338 |
|
| 1339 |
|
| 1340 | static int find_key(struct ro_spine *s, dm_block_t block, bool find_highest,
|
| 1341 | uint64_t *result_key, dm_block_t *next_block)
|
| 1342 | {
|
| 1343 | int i, r;
|
| 1344 | uint32_t flags;
|
| 1345 |
|
| 1346 | do {
|
| 1347 | r = ro_step(s, block);
|
| 1348 | if (r < 0)
|
| 1349 | return r;
|
| 1350 |
|
| 1351 | flags = le32_to_cpu(ro_node(s)->header.flags);
|
| 1352 | i = le32_to_cpu(ro_node(s)->header.nr_entries);
|
| 1353 | if (!i)
|
| 1354 | return -ENODATA;
|
| 1355 |
|
| 1356 | i--;
|
| 1357 |
|
| 1358 | if (find_highest)
|
| 1359 | *result_key = le64_to_cpu(ro_node(s)->keys[i]);
|
| 1360 | else
|
| 1361 | *result_key = le64_to_cpu(ro_node(s)->keys[0]);
|
| 1362 |
|
| 1363 | if (next_block || flags & INTERNAL_NODE) {
|
| 1364 | if (find_highest)
|
| 1365 | block = value64(ro_node(s), i);
|
| 1366 | else
|
| 1367 | block = value64(ro_node(s), 0);
|
| 1368 | }
|
| 1369 |
|
| 1370 | } while (flags & INTERNAL_NODE);
|
| 1371 |
|
| 1372 | if (next_block)
|
| 1373 | *next_block = block;
|
| 1374 | return 0;
|
| 1375 | }
|
| 1376 |
|
| 1377 | static int dm_btree_find_key(struct dm_btree_info *info, dm_block_t root,
|
| 1378 | bool find_highest, uint64_t *result_keys)
|
| 1379 | {
|
| 1380 | int r = 0, count = 0, level;
|
| 1381 | struct ro_spine spine;
|
| 1382 |
|
| 1383 | init_ro_spine(&spine, info);
|
| 1384 | for (level = 0; level < info->levels; level++) {
|
| 1385 | r = find_key(&spine, root, find_highest, result_keys + level,
|
| 1386 | level == info->levels - 1 ? NULL : &root);
|
| 1387 | if (r == -ENODATA) {
|
| 1388 | r = 0;
|
| 1389 | break;
|
| 1390 |
|
| 1391 | } else if (r)
|
| 1392 | break;
|
| 1393 |
|
| 1394 | count++;
|
| 1395 | }
|
| 1396 | exit_ro_spine(&spine);
|
| 1397 |
|
| 1398 | return r ? r : count;
|
| 1399 | }
|
| 1400 |
|
| 1401 | int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
|
| 1402 | uint64_t *result_keys)
|
| 1403 | {
|
| 1404 | return dm_btree_find_key(info, root, true, result_keys);
|
| 1405 | }
|
| 1406 | EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);
|
| 1407 |
|
| 1408 | int dm_btree_find_lowest_key(struct dm_btree_info *info, dm_block_t root,
|
| 1409 | uint64_t *result_keys)
|
| 1410 | {
|
| 1411 | return dm_btree_find_key(info, root, false, result_keys);
|
| 1412 | }
|
| 1413 | EXPORT_SYMBOL_GPL(dm_btree_find_lowest_key);
|
| 1414 |
|
| 1415 |
|
| 1416 |
|
| 1417 | |
| 1418 | * FIXME: We shouldn't use a recursive algorithm when we have limited stack
|
| 1419 | * space. Also this only works for single level trees.
|
| 1420 |
|
| 1421 | static int walk_node(struct dm_btree_info *info, dm_block_t block,
|
| 1422 | int (*fn)(void *context, uint64_t *keys, void *leaf),
|
| 1423 | void *context)
|
| 1424 | {
|
| 1425 | int r;
|
| 1426 | unsigned int i, nr;
|
| 1427 | struct dm_block *node;
|
| 1428 | struct btree_node *n;
|
| 1429 | uint64_t keys;
|
| 1430 |
|
| 1431 | r = bn_read_lock(info, block, &node);
|
| 1432 | if (r)
|
| 1433 | return r;
|
| 1434 |
|
| 1435 | n = dm_block_data(node);
|
| 1436 |
|
| 1437 | nr = le32_to_cpu(n->header.nr_entries);
|
| 1438 | for (i = 0; i < nr; i++) {
|
| 1439 | if (le32_to_cpu(n->header.flags) & INTERNAL_NODE) {
|
| 1440 | r = walk_node(info, value64(n, i), fn, context);
|
| 1441 | if (r)
|
| 1442 | goto out;
|
| 1443 | } else {
|
| 1444 | keys = le64_to_cpu(*key_ptr(n, i));
|
| 1445 | r = fn(context, &keys, value_ptr(n, i));
|
| 1446 | if (r)
|
| 1447 | goto out;
|
| 1448 | }
|
| 1449 | }
|
| 1450 |
|
| 1451 | out:
|
| 1452 | dm_tm_unlock(info->tm, node);
|
| 1453 | return r;
|
| 1454 | }
|
| 1455 |
|
| 1456 | int dm_btree_walk(struct dm_btree_info *info, dm_block_t root,
|
| 1457 | int (*fn)(void *context, uint64_t *keys, void *leaf),
|
| 1458 | void *context)
|
| 1459 | {
|
| 1460 | BUG_ON(info->levels > 1);
|
| 1461 | return walk_node(info, root, fn, context);
|
| 1462 | }
|
| 1463 | EXPORT_SYMBOL_GPL(dm_btree_walk);
|
| 1464 |
|
| 1465 |
|
| 1466 |
|
| 1467 | static void prefetch_values(struct dm_btree_cursor *c)
|
| 1468 | {
|
| 1469 | unsigned int i, nr;
|
| 1470 | __le64 value_le;
|
| 1471 | struct cursor_node *n = c->nodes + c->depth - 1;
|
| 1472 | struct btree_node *bn = dm_block_data(n->b);
|
| 1473 | struct dm_block_manager *bm = dm_tm_get_bm(c->info->tm);
|
| 1474 |
|
| 1475 | BUG_ON(c->info->value_type.size != sizeof(value_le));
|
| 1476 |
|
| 1477 | nr = le32_to_cpu(bn->header.nr_entries);
|
| 1478 | for (i = 0; i < nr; i++) {
|
| 1479 | memcpy(&value_le, value_ptr(bn, i), sizeof(value_le));
|
| 1480 | dm_bm_prefetch(bm, le64_to_cpu(value_le));
|
| 1481 | }
|
| 1482 | }
|
| 1483 |
|
| 1484 | static bool leaf_node(struct dm_btree_cursor *c)
|
| 1485 | {
|
| 1486 | struct cursor_node *n = c->nodes + c->depth - 1;
|
| 1487 | struct btree_node *bn = dm_block_data(n->b);
|
| 1488 |
|
| 1489 | return le32_to_cpu(bn->header.flags) & LEAF_NODE;
|
| 1490 | }
|
| 1491 |
|
| 1492 | static int push_node(struct dm_btree_cursor *c, dm_block_t b)
|
| 1493 | {
|
| 1494 | int r;
|
| 1495 | struct cursor_node *n = c->nodes + c->depth;
|
| 1496 |
|
| 1497 | if (c->depth >= DM_BTREE_CURSOR_MAX_DEPTH - 1) {
|
| 1498 | DMERR("couldn't push cursor node, stack depth too high");
|
| 1499 | return -EINVAL;
|
| 1500 | }
|
| 1501 |
|
| 1502 | r = bn_read_lock(c->info, b, &n->b);
|
| 1503 | if (r)
|
| 1504 | return r;
|
| 1505 |
|
| 1506 | n->index = 0;
|
| 1507 | c->depth++;
|
| 1508 |
|
| 1509 | if (c->prefetch_leaves || !leaf_node(c))
|
| 1510 | prefetch_values(c);
|
| 1511 |
|
| 1512 | return 0;
|
| 1513 | }
|
| 1514 |
|
| 1515 | static void pop_node(struct dm_btree_cursor *c)
|
| 1516 | {
|
| 1517 | c->depth--;
|
| 1518 | unlock_block(c->info, c->nodes[c->depth].b);
|
| 1519 | }
|
| 1520 |
|
| 1521 | static int inc_or_backtrack(struct dm_btree_cursor *c)
|
| 1522 | {
|
| 1523 | struct cursor_node *n;
|
| 1524 | struct btree_node *bn;
|
| 1525 |
|
| 1526 | for (;;) {
|
| 1527 | if (!c->depth)
|
| 1528 | return -ENODATA;
|
| 1529 |
|
| 1530 | n = c->nodes + c->depth - 1;
|
| 1531 | bn = dm_block_data(n->b);
|
| 1532 |
|
| 1533 | n->index++;
|
| 1534 | if (n->index < le32_to_cpu(bn->header.nr_entries))
|
| 1535 | break;
|
| 1536 |
|
| 1537 | pop_node(c);
|
| 1538 | }
|
| 1539 |
|
| 1540 | return 0;
|
| 1541 | }
|
| 1542 |
|
| 1543 | static int find_leaf(struct dm_btree_cursor *c)
|
| 1544 | {
|
| 1545 | int r = 0;
|
| 1546 | struct cursor_node *n;
|
| 1547 | struct btree_node *bn;
|
| 1548 | __le64 value_le;
|
| 1549 |
|
| 1550 | for (;;) {
|
| 1551 | n = c->nodes + c->depth - 1;
|
| 1552 | bn = dm_block_data(n->b);
|
| 1553 |
|
| 1554 | if (le32_to_cpu(bn->header.flags) & LEAF_NODE)
|
| 1555 | break;
|
| 1556 |
|
| 1557 | memcpy(&value_le, value_ptr(bn, n->index), sizeof(value_le));
|
| 1558 | r = push_node(c, le64_to_cpu(value_le));
|
| 1559 | if (r) {
|
| 1560 | DMERR("push_node failed");
|
| 1561 | break;
|
| 1562 | }
|
| 1563 | }
|
| 1564 |
|
| 1565 | if (!r && (le32_to_cpu(bn->header.nr_entries) == 0))
|
| 1566 | return -ENODATA;
|
| 1567 |
|
| 1568 | return r;
|
| 1569 | }
|
| 1570 |
|
| 1571 | int dm_btree_cursor_begin(struct dm_btree_info *info, dm_block_t root,
|
| 1572 | bool prefetch_leaves, struct dm_btree_cursor *c)
|
| 1573 | {
|
| 1574 | int r;
|
| 1575 |
|
| 1576 | c->info = info;
|
| 1577 | c->root = root;
|
| 1578 | c->depth = 0;
|
| 1579 | c->prefetch_leaves = prefetch_leaves;
|
| 1580 |
|
| 1581 | r = push_node(c, root);
|
| 1582 | if (r)
|
| 1583 | return r;
|
| 1584 |
|
| 1585 | return find_leaf(c);
|
| 1586 | }
|
| 1587 | EXPORT_SYMBOL_GPL(dm_btree_cursor_begin);
|
| 1588 |
|
| 1589 | void dm_btree_cursor_end(struct dm_btree_cursor *c)
|
| 1590 | {
|
| 1591 | while (c->depth)
|
| 1592 | pop_node(c);
|
| 1593 | }
|
| 1594 | EXPORT_SYMBOL_GPL(dm_btree_cursor_end);
|
| 1595 |
|
| 1596 | int dm_btree_cursor_next(struct dm_btree_cursor *c)
|
| 1597 | {
|
| 1598 | int r = inc_or_backtrack(c);
|
| 1599 |
|
| 1600 | if (!r) {
|
| 1601 | r = find_leaf(c);
|
| 1602 | if (r)
|
| 1603 | DMERR("find_leaf failed");
|
| 1604 | }
|
| 1605 |
|
| 1606 | return r;
|
| 1607 | }
|
| 1608 | EXPORT_SYMBOL_GPL(dm_btree_cursor_next);
|
| 1609 |
|
| 1610 | int dm_btree_cursor_skip(struct dm_btree_cursor *c, uint32_t count)
|
| 1611 | {
|
| 1612 | int r = 0;
|
| 1613 |
|
| 1614 | while (count-- && !r)
|
| 1615 | r = dm_btree_cursor_next(c);
|
| 1616 |
|
| 1617 | return r;
|
| 1618 | }
|
| 1619 | EXPORT_SYMBOL_GPL(dm_btree_cursor_skip);
|
| 1620 |
|
| 1621 | int dm_btree_cursor_get_value(struct dm_btree_cursor *c, uint64_t *key, void *value_le)
|
| 1622 | {
|
| 1623 | if (c->depth) {
|
| 1624 | struct cursor_node *n = c->nodes + c->depth - 1;
|
| 1625 | struct btree_node *bn = dm_block_data(n->b);
|
| 1626 |
|
| 1627 | if (le32_to_cpu(bn->header.flags) & INTERNAL_NODE)
|
| 1628 | return -EINVAL;
|
| 1629 |
|
| 1630 | *key = le64_to_cpu(*key_ptr(bn, n->index));
|
| 1631 | memcpy(value_le, value_ptr(bn, n->index), c->info->value_type.size);
|
| 1632 | return 0;
|
| 1633 |
|
| 1634 | } else
|
| 1635 | return -ENODATA;
|
| 1636 | }
|
| 1637 | EXPORT_SYMBOL_GPL(dm_btree_cursor_get_value);
|