fs/nilfs2/btree.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * NILFS B-tree.
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Written by Koji Sato.
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/string.h>
  12 #include <linux/errno.h>
  13 #include <linux/pagevec.h>
  14 #include "nilfs.h"
  15 #include "page.h"
  16 #include "btnode.h"
  17 #include "btree.h"
  18 #include "alloc.h"
  19 #include "dat.h"
  20
  21 static void __nilfs_btree_init(struct nilfs_bmap *bmap);
  22
  23 static struct nilfs_btree_path *nilfs_btree_alloc_path(void)
  24 {
  25         struct nilfs_btree_path *path;
  26         int level = NILFS_BTREE_LEVEL_DATA;
  27
  28         path = kmem_cache_alloc(nilfs_btree_path_cache, GFP_NOFS);
  29         if (path == NULL)
  30                 goto out;
  31
  32         for (; level < NILFS_BTREE_LEVEL_MAX; level++) {
  33                 path[level].bp_bh = NULL;
  34                 path[level].bp_sib_bh = NULL;
  35                 path[level].bp_index = 0;
  36                 path[level].bp_oldreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
  37                 path[level].bp_newreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
  38                 path[level].bp_op = NULL;
  39         }
  40
  41 out:
  42         return path;
  43 }
  44
  45 static void nilfs_btree_free_path(struct nilfs_btree_path *path)
  46 {
  47         int level = NILFS_BTREE_LEVEL_DATA;
  48
  49         for (; level < NILFS_BTREE_LEVEL_MAX; level++)
  50                 brelse(path[level].bp_bh);
  51
  52         kmem_cache_free(nilfs_btree_path_cache, path);
  53 }
  54
  55 /*
  56  * B-tree node operations
  57  */
  58 static int nilfs_btree_get_new_block(const struct nilfs_bmap *btree,
  59                                      __u64 ptr, struct buffer_head **bhp)
  60 {
  61         struct inode *btnc_inode = NILFS_BMAP_I(btree)->i_assoc_inode;
  62         struct address_space *btnc = btnc_inode->i_mapping;
  63         struct buffer_head *bh;
  64
  65         bh = nilfs_btnode_create_block(btnc, ptr);
  66         if (!bh)
  67                 return -ENOMEM;
  68
  69         set_buffer_nilfs_volatile(bh);
  70         *bhp = bh;
  71         return 0;
  72 }
  73
  74 static int nilfs_btree_node_get_flags(const struct nilfs_btree_node *node)
  75 {
  76         return node->bn_flags;
  77 }
  78
  79 static void
  80 nilfs_btree_node_set_flags(struct nilfs_btree_node *node, int flags)
  81 {
  82         node->bn_flags = flags;
  83 }
  84
  85 static int nilfs_btree_node_root(const struct nilfs_btree_node *node)
  86 {
  87         return nilfs_btree_node_get_flags(node) & NILFS_BTREE_NODE_ROOT;
  88 }
  89
  90 static int nilfs_btree_node_get_level(const struct nilfs_btree_node *node)
  91 {
  92         return node->bn_level;
  93 }
  94
  95 static void
  96 nilfs_btree_node_set_level(struct nilfs_btree_node *node, int level)
  97 {
  98         node->bn_level = level;
  99 }
 100
 101 static int nilfs_btree_node_get_nchildren(const struct nilfs_btree_node *node)
 102 {
 103         return le16_to_cpu(node->bn_nchildren);
 104 }
 105
 106 static void
 107 nilfs_btree_node_set_nchildren(struct nilfs_btree_node *node, int nchildren)
 108 {
 109         node->bn_nchildren = cpu_to_le16(nchildren);
 110 }
 111
 112 static int nilfs_btree_node_size(const struct nilfs_bmap *btree)
 113 {
 114         return i_blocksize(btree->b_inode);
 115 }
 116
 117 static int nilfs_btree_nchildren_per_block(const struct nilfs_bmap *btree)
 118 {
 119         return btree->b_nchildren_per_block;
 120 }
 121
 122 static __le64 *
 123 nilfs_btree_node_dkeys(const struct nilfs_btree_node *node)
 124 {
 125         return (__le64 *)((char *)(node + 1) +
 126                           (nilfs_btree_node_root(node) ?
 127                            0 : NILFS_BTREE_NODE_EXTRA_PAD_SIZE));
 128 }
 129
 130 static __le64 *
 131 nilfs_btree_node_dptrs(const struct nilfs_btree_node *node, int ncmax)
 132 {
 133         return (__le64 *)(nilfs_btree_node_dkeys(node) + ncmax);
 134 }
 135
 136 static __u64
 137 nilfs_btree_node_get_key(const struct nilfs_btree_node *node, int index)
 138 {
 139         return le64_to_cpu(*(nilfs_btree_node_dkeys(node) + index));
 140 }
 141
 142 static void
 143 nilfs_btree_node_set_key(struct nilfs_btree_node *node, int index, __u64 key)
 144 {
 145         *(nilfs_btree_node_dkeys(node) + index) = cpu_to_le64(key);
 146 }
 147
 148 static __u64
 149 nilfs_btree_node_get_ptr(const struct nilfs_btree_node *node, int index,
 150                          int ncmax)
 151 {
 152         return le64_to_cpu(*(nilfs_btree_node_dptrs(node, ncmax) + index));
 153 }
 154
 155 static void
 156 nilfs_btree_node_set_ptr(struct nilfs_btree_node *node, int index, __u64 ptr,
 157                          int ncmax)
 158 {
 159         *(nilfs_btree_node_dptrs(node, ncmax) + index) = cpu_to_le64(ptr);
 160 }
 161
 162 static void nilfs_btree_node_init(struct nilfs_btree_node *node, int flags,
 163                                   int level, int nchildren, int ncmax,
 164                                   const __u64 *keys, const __u64 *ptrs)
 165 {
 166         __le64 *dkeys;
 167         __le64 *dptrs;
 168         int i;
 169
 170         nilfs_btree_node_set_flags(node, flags);
 171         nilfs_btree_node_set_level(node, level);
 172         nilfs_btree_node_set_nchildren(node, nchildren);
 173
 174         dkeys = nilfs_btree_node_dkeys(node);
 175         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 176         for (i = 0; i < nchildren; i++) {
 177                 dkeys[i] = cpu_to_le64(keys[i]);
 178                 dptrs[i] = cpu_to_le64(ptrs[i]);
 179         }
 180 }
 181
 182 /* Assume the buffer heads corresponding to left and right are locked. */
 183 static void nilfs_btree_node_move_left(struct nilfs_btree_node *left,
 184                                        struct nilfs_btree_node *right,
 185                                        int n, int lncmax, int rncmax)
 186 {
 187         __le64 *ldkeys, *rdkeys;
 188         __le64 *ldptrs, *rdptrs;
 189         int lnchildren, rnchildren;
 190
 191         ldkeys = nilfs_btree_node_dkeys(left);
 192         ldptrs = nilfs_btree_node_dptrs(left, lncmax);
 193         lnchildren = nilfs_btree_node_get_nchildren(left);
 194
 195         rdkeys = nilfs_btree_node_dkeys(right);
 196         rdptrs = nilfs_btree_node_dptrs(right, rncmax);
 197         rnchildren = nilfs_btree_node_get_nchildren(right);
 198
 199         memcpy(ldkeys + lnchildren, rdkeys, n * sizeof(*rdkeys));
 200         memcpy(ldptrs + lnchildren, rdptrs, n * sizeof(*rdptrs));
 201         memmove(rdkeys, rdkeys + n, (rnchildren - n) * sizeof(*rdkeys));
 202         memmove(rdptrs, rdptrs + n, (rnchildren - n) * sizeof(*rdptrs));
 203
 204         lnchildren += n;
 205         rnchildren -= n;
 206         nilfs_btree_node_set_nchildren(left, lnchildren);
 207         nilfs_btree_node_set_nchildren(right, rnchildren);
 208 }
 209
 210 /* Assume that the buffer heads corresponding to left and right are locked. */
 211 static void nilfs_btree_node_move_right(struct nilfs_btree_node *left,
 212                                         struct nilfs_btree_node *right,
 213                                         int n, int lncmax, int rncmax)
 214 {
 215         __le64 *ldkeys, *rdkeys;
 216         __le64 *ldptrs, *rdptrs;
 217         int lnchildren, rnchildren;
 218
 219         ldkeys = nilfs_btree_node_dkeys(left);
 220         ldptrs = nilfs_btree_node_dptrs(left, lncmax);
 221         lnchildren = nilfs_btree_node_get_nchildren(left);
 222
 223         rdkeys = nilfs_btree_node_dkeys(right);
 224         rdptrs = nilfs_btree_node_dptrs(right, rncmax);
 225         rnchildren = nilfs_btree_node_get_nchildren(right);
 226
 227         memmove(rdkeys + n, rdkeys, rnchildren * sizeof(*rdkeys));
 228         memmove(rdptrs + n, rdptrs, rnchildren * sizeof(*rdptrs));
 229         memcpy(rdkeys, ldkeys + lnchildren - n, n * sizeof(*rdkeys));
 230         memcpy(rdptrs, ldptrs + lnchildren - n, n * sizeof(*rdptrs));
 231
 232         lnchildren -= n;
 233         rnchildren += n;
 234         nilfs_btree_node_set_nchildren(left, lnchildren);
 235         nilfs_btree_node_set_nchildren(right, rnchildren);
 236 }
 237
 238 /* Assume that the buffer head corresponding to node is locked. */
 239 static void nilfs_btree_node_insert(struct nilfs_btree_node *node, int index,
 240                                     __u64 key, __u64 ptr, int ncmax)
 241 {
 242         __le64 *dkeys;
 243         __le64 *dptrs;
 244         int nchildren;
 245
 246         dkeys = nilfs_btree_node_dkeys(node);
 247         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 248         nchildren = nilfs_btree_node_get_nchildren(node);
 249         if (index < nchildren) {
 250                 memmove(dkeys + index + 1, dkeys + index,
 251                         (nchildren - index) * sizeof(*dkeys));
 252                 memmove(dptrs + index + 1, dptrs + index,
 253                         (nchildren - index) * sizeof(*dptrs));
 254         }
 255         dkeys[index] = cpu_to_le64(key);
 256         dptrs[index] = cpu_to_le64(ptr);
 257         nchildren++;
 258         nilfs_btree_node_set_nchildren(node, nchildren);
 259 }
 260
 261 /* Assume that the buffer head corresponding to node is locked. */
 262 static void nilfs_btree_node_delete(struct nilfs_btree_node *node, int index,
 263                                     __u64 *keyp, __u64 *ptrp, int ncmax)
 264 {
 265         __u64 key;
 266         __u64 ptr;
 267         __le64 *dkeys;
 268         __le64 *dptrs;
 269         int nchildren;
 270
 271         dkeys = nilfs_btree_node_dkeys(node);
 272         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 273         key = le64_to_cpu(dkeys[index]);
 274         ptr = le64_to_cpu(dptrs[index]);
 275         nchildren = nilfs_btree_node_get_nchildren(node);
 276         if (keyp != NULL)
 277                 *keyp = key;
 278         if (ptrp != NULL)
 279                 *ptrp = ptr;
 280
 281         if (index < nchildren - 1) {
 282                 memmove(dkeys + index, dkeys + index + 1,
 283                         (nchildren - index - 1) * sizeof(*dkeys));
 284                 memmove(dptrs + index, dptrs + index + 1,
 285                         (nchildren - index - 1) * sizeof(*dptrs));
 286         }
 287         nchildren--;
 288         nilfs_btree_node_set_nchildren(node, nchildren);
 289 }
 290
 291 static int nilfs_btree_node_lookup(const struct nilfs_btree_node *node,
 292                                    __u64 key, int *indexp)
 293 {
 294         __u64 nkey;
 295         int index, low, high, s;
 296
 297         /* binary search */
 298         low = 0;
 299         high = nilfs_btree_node_get_nchildren(node) - 1;
 300         index = 0;
 301         s = 0;
 302         while (low <= high) {
 303                 index = (low + high) / 2;
 304                 nkey = nilfs_btree_node_get_key(node, index);
 305                 if (nkey == key) {
 306                         s = 0;
 307                         goto out;
 308                 } else if (nkey < key) {
 309                         low = index + 1;
 310                         s = -1;
 311                 } else {
 312                         high = index - 1;
 313                         s = 1;
 314                 }
 315         }
 316
 317         /* adjust index */
 318         if (nilfs_btree_node_get_level(node) > NILFS_BTREE_LEVEL_NODE_MIN) {
 319                 if (s > 0 && index > 0)
 320                         index--;
 321         } else if (s < 0)
 322                 index++;
 323
 324  out:
 325         *indexp = index;
 326
 327         return s == 0;
 328 }
 329
 330 /**
 331  * nilfs_btree_node_broken - verify consistency of btree node
 332  * @node: btree node block to be examined
 333  * @size: node size (in bytes)
 334  * @inode: host inode of btree
 335  * @blocknr: block number
 336  *
 337  * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
 338  */
 339 static int nilfs_btree_node_broken(const struct nilfs_btree_node *node,
 340                                    size_t size, struct inode *inode,
 341                                    sector_t blocknr)
 342 {
 343         int level, flags, nchildren;
 344         int ret = 0;
 345
 346         level = nilfs_btree_node_get_level(node);
 347         flags = nilfs_btree_node_get_flags(node);
 348         nchildren = nilfs_btree_node_get_nchildren(node);
 349
 350         if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
 351                      level >= NILFS_BTREE_LEVEL_MAX ||
 352                      (flags & NILFS_BTREE_NODE_ROOT) ||
 353                      nchildren < 0 ||
 354                      nchildren > NILFS_BTREE_NODE_NCHILDREN_MAX(size))) {
 355                 nilfs_crit(inode->i_sb,
 356                            "bad btree node (ino=%lu, blocknr=%llu): level = %d, flags = 0x%x, nchildren = %d",
 357                            inode->i_ino, (unsigned long long)blocknr, level,
 358                            flags, nchildren);
 359                 ret = 1;
 360         }
 361         return ret;
 362 }
 363
 364 /**
 365  * nilfs_btree_root_broken - verify consistency of btree root node
 366  * @node: btree root node to be examined
 367  * @inode: host inode of btree
 368  *
 369  * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
 370  */
 371 static int nilfs_btree_root_broken(const struct nilfs_btree_node *node,
 372                                    struct inode *inode)
 373 {
 374         int level, flags, nchildren;
 375         int ret = 0;
 376
 377         level = nilfs_btree_node_get_level(node);
 378         flags = nilfs_btree_node_get_flags(node);
 379         nchildren = nilfs_btree_node_get_nchildren(node);
 380
 381         if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
 382                      level >= NILFS_BTREE_LEVEL_MAX ||
 383                      nchildren < 0 ||
 384                      nchildren > NILFS_BTREE_ROOT_NCHILDREN_MAX)) {
 385                 nilfs_crit(inode->i_sb,
 386                            "bad btree root (ino=%lu): level = %d, flags = 0x%x, nchildren = %d",
 387                            inode->i_ino, level, flags, nchildren);
 388                 ret = 1;
 389         }
 390         return ret;
 391 }
 392
 393 int nilfs_btree_broken_node_block(struct buffer_head *bh)
 394 {
 395         struct inode *inode;
 396         int ret;
 397
 398         if (buffer_nilfs_checked(bh))
 399                 return 0;
 400
 401         inode = bh->b_page->mapping->host;
 402         ret = nilfs_btree_node_broken((struct nilfs_btree_node *)bh->b_data,
 403                                       bh->b_size, inode, bh->b_blocknr);
 404         if (likely(!ret))
 405                 set_buffer_nilfs_checked(bh);
 406         return ret;
 407 }
 408
 409 static struct nilfs_btree_node *
 410 nilfs_btree_get_root(const struct nilfs_bmap *btree)
 411 {
 412         return (struct nilfs_btree_node *)btree->b_u.u_data;
 413 }
 414
 415 static struct nilfs_btree_node *
 416 nilfs_btree_get_nonroot_node(const struct nilfs_btree_path *path, int level)
 417 {
 418         return (struct nilfs_btree_node *)path[level].bp_bh->b_data;
 419 }
 420
 421 static struct nilfs_btree_node *
 422 nilfs_btree_get_sib_node(const struct nilfs_btree_path *path, int level)
 423 {
 424         return (struct nilfs_btree_node *)path[level].bp_sib_bh->b_data;
 425 }
 426
 427 static int nilfs_btree_height(const struct nilfs_bmap *btree)
 428 {
 429         return nilfs_btree_node_get_level(nilfs_btree_get_root(btree)) + 1;
 430 }
 431
 432 static struct nilfs_btree_node *
 433 nilfs_btree_get_node(const struct nilfs_bmap *btree,
 434                      const struct nilfs_btree_path *path,
 435                      int level, int *ncmaxp)
 436 {
 437         struct nilfs_btree_node *node;
 438
 439         if (level == nilfs_btree_height(btree) - 1) {
 440                 node = nilfs_btree_get_root(btree);
 441                 *ncmaxp = NILFS_BTREE_ROOT_NCHILDREN_MAX;
 442         } else {
 443                 node = nilfs_btree_get_nonroot_node(path, level);
 444                 *ncmaxp = nilfs_btree_nchildren_per_block(btree);
 445         }
 446         return node;
 447 }
 448
 449 static int nilfs_btree_bad_node(const struct nilfs_bmap *btree,
 450                                 struct nilfs_btree_node *node, int level)
 451 {
 452         if (unlikely(nilfs_btree_node_get_level(node) != level)) {
 453                 dump_stack();
 454                 nilfs_crit(btree->b_inode->i_sb,
 455                            "btree level mismatch (ino=%lu): %d != %d",
 456                            btree->b_inode->i_ino,
 457                            nilfs_btree_node_get_level(node), level);
 458                 return 1;
 459         }
 460         return 0;
 461 }
 462
 463 struct nilfs_btree_readahead_info {
 464         struct nilfs_btree_node *node;  /* parent node */
 465         int max_ra_blocks;              /* max nof blocks to read ahead */
 466         int index;                      /* current index on the parent node */
 467         int ncmax;                      /* nof children in the parent node */
 468 };
 469
 470 static int __nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
 471                                    struct buffer_head **bhp,
 472                                    const struct nilfs_btree_readahead_info *ra)
 473 {
 474         struct inode *btnc_inode = NILFS_BMAP_I(btree)->i_assoc_inode;
 475         struct address_space *btnc = btnc_inode->i_mapping;
 476         struct buffer_head *bh, *ra_bh;
 477         sector_t submit_ptr = 0;
 478         int ret;
 479
 480         ret = nilfs_btnode_submit_block(btnc, ptr, 0, REQ_OP_READ, &bh,
 481                                         &submit_ptr);
 482         if (ret) {
 483                 if (ret != -EEXIST)
 484                         return ret;
 485                 goto out_check;
 486         }
 487
 488         if (ra) {
 489                 int i, n;
 490                 __u64 ptr2;
 491
 492                 /* read ahead sibling nodes */
 493                 for (n = ra->max_ra_blocks, i = ra->index + 1;
 494                      n > 0 && i < ra->ncmax; n--, i++) {
 495                         ptr2 = nilfs_btree_node_get_ptr(ra->node, i, ra->ncmax);
 496
 497                         ret = nilfs_btnode_submit_block(btnc, ptr2, 0,
 498                                                 REQ_OP_READ | REQ_RAHEAD,
 499                                                 &ra_bh, &submit_ptr);
 500                         if (likely(!ret || ret == -EEXIST))
 501                                 brelse(ra_bh);
 502                         else if (ret != -EBUSY)
 503                                 break;
 504                         if (!buffer_locked(bh))
 505                                 goto out_no_wait;
 506                 }
 507         }
 508
 509         wait_on_buffer(bh);
 510
 511  out_no_wait:
 512         if (!buffer_uptodate(bh)) {
 513                 nilfs_err(btree->b_inode->i_sb,
 514                           "I/O error reading b-tree node block (ino=%lu, blocknr=%llu)",
 515                           btree->b_inode->i_ino, (unsigned long long)ptr);
 516                 brelse(bh);
 517                 return -EIO;
 518         }
 519
 520  out_check:
 521         if (nilfs_btree_broken_node_block(bh)) {
 522                 clear_buffer_uptodate(bh);
 523                 brelse(bh);
 524                 return -EINVAL;
 525         }
 526
 527         *bhp = bh;
 528         return 0;
 529 }
 530
 531 static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
 532                                    struct buffer_head **bhp)
 533 {
 534         return __nilfs_btree_get_block(btree, ptr, bhp, NULL);
 535 }
 536
 537 static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree,
 538                                  struct nilfs_btree_path *path,
 539                                  __u64 key, __u64 *ptrp, int minlevel,
 540                                  int readahead)
 541 {
 542         struct nilfs_btree_node *node;
 543         struct nilfs_btree_readahead_info p, *ra;
 544         __u64 ptr;
 545         int level, index, found, ncmax, ret;
 546
 547         node = nilfs_btree_get_root(btree);
 548         level = nilfs_btree_node_get_level(node);
 549         if (level < minlevel || nilfs_btree_node_get_nchildren(node) <= 0)
 550                 return -ENOENT;
 551
 552         found = nilfs_btree_node_lookup(node, key, &index);
 553         ptr = nilfs_btree_node_get_ptr(node, index,
 554                                        NILFS_BTREE_ROOT_NCHILDREN_MAX);
 555         path[level].bp_bh = NULL;
 556         path[level].bp_index = index;
 557
 558         ncmax = nilfs_btree_nchildren_per_block(btree);
 559
 560         while (--level >= minlevel) {
 561                 ra = NULL;
 562                 if (level == NILFS_BTREE_LEVEL_NODE_MIN && readahead) {
 563                         p.node = nilfs_btree_get_node(btree, path, level + 1,
 564                                                       &p.ncmax);
 565                         p.index = index;
 566                         p.max_ra_blocks = 7;
 567                         ra = &p;
 568                 }
 569                 ret = __nilfs_btree_get_block(btree, ptr, &path[level].bp_bh,
 570                                               ra);
 571                 if (ret < 0)
 572                         return ret;
 573
 574                 node = nilfs_btree_get_nonroot_node(path, level);
 575                 if (nilfs_btree_bad_node(btree, node, level))
 576                         return -EINVAL;
 577                 if (!found)
 578                         found = nilfs_btree_node_lookup(node, key, &index);
 579                 else
 580                         index = 0;
 581                 if (index < ncmax) {
 582                         ptr = nilfs_btree_node_get_ptr(node, index, ncmax);
 583                 } else {
 584                         WARN_ON(found || level != NILFS_BTREE_LEVEL_NODE_MIN);
 585                         /* insert */
 586                         ptr = NILFS_BMAP_INVALID_PTR;
 587                 }
 588                 path[level].bp_index = index;
 589         }
 590         if (!found)
 591                 return -ENOENT;
 592
 593         if (ptrp != NULL)
 594                 *ptrp = ptr;
 595
 596         return 0;
 597 }
 598
 599 static int nilfs_btree_do_lookup_last(const struct nilfs_bmap *btree,
 600                                       struct nilfs_btree_path *path,
 601                                       __u64 *keyp, __u64 *ptrp)
 602 {
 603         struct nilfs_btree_node *node;
 604         __u64 ptr;
 605         int index, level, ncmax, ret;
 606
 607         node = nilfs_btree_get_root(btree);
 608         index = nilfs_btree_node_get_nchildren(node) - 1;
 609         if (index < 0)
 610                 return -ENOENT;
 611         level = nilfs_btree_node_get_level(node);
 612         ptr = nilfs_btree_node_get_ptr(node, index,
 613                                        NILFS_BTREE_ROOT_NCHILDREN_MAX);
 614         path[level].bp_bh = NULL;
 615         path[level].bp_index = index;
 616         ncmax = nilfs_btree_nchildren_per_block(btree);
 617
 618         for (level--; level > 0; level--) {
 619                 ret = nilfs_btree_get_block(btree, ptr, &path[level].bp_bh);
 620                 if (ret < 0)
 621                         return ret;
 622                 node = nilfs_btree_get_nonroot_node(path, level);
 623                 if (nilfs_btree_bad_node(btree, node, level))
 624                         return -EINVAL;
 625                 index = nilfs_btree_node_get_nchildren(node) - 1;
 626                 ptr = nilfs_btree_node_get_ptr(node, index, ncmax);
 627                 path[level].bp_index = index;
 628         }
 629
 630         if (keyp != NULL)
 631                 *keyp = nilfs_btree_node_get_key(node, index);
 632         if (ptrp != NULL)
 633                 *ptrp = ptr;
 634
 635         return 0;
 636 }
 637
 638 /**
 639  * nilfs_btree_get_next_key - get next valid key from btree path array
 640  * @btree: bmap struct of btree
 641  * @path: array of nilfs_btree_path struct
 642  * @minlevel: start level
 643  * @nextkey: place to store the next valid key
 644  *
 645  * Return Value: If a next key was found, 0 is returned. Otherwise,
 646  * -ENOENT is returned.
 647  */
 648 static int nilfs_btree_get_next_key(const struct nilfs_bmap *btree,
 649                                     const struct nilfs_btree_path *path,
 650                                     int minlevel, __u64 *nextkey)
 651 {
 652         struct nilfs_btree_node *node;
 653         int maxlevel = nilfs_btree_height(btree) - 1;
 654         int index, next_adj, level;
 655
 656         /* Next index is already set to bp_index for leaf nodes. */
 657         next_adj = 0;
 658         for (level = minlevel; level <= maxlevel; level++) {
 659                 if (level == maxlevel)
 660                         node = nilfs_btree_get_root(btree);
 661                 else
 662                         node = nilfs_btree_get_nonroot_node(path, level);
 663
 664                 index = path[level].bp_index + next_adj;
 665                 if (index < nilfs_btree_node_get_nchildren(node)) {
 666                         /* Next key is in this node */
 667                         *nextkey = nilfs_btree_node_get_key(node, index);
 668                         return 0;
 669                 }
 670                 /* For non-leaf nodes, next index is stored at bp_index + 1. */
 671                 next_adj = 1;
 672         }
 673         return -ENOENT;
 674 }
 675
 676 static int nilfs_btree_lookup(const struct nilfs_bmap *btree,
 677                               __u64 key, int level, __u64 *ptrp)
 678 {
 679         struct nilfs_btree_path *path;
 680         int ret;
 681
 682         path = nilfs_btree_alloc_path();
 683         if (path == NULL)
 684                 return -ENOMEM;
 685
 686         ret = nilfs_btree_do_lookup(btree, path, key, ptrp, level, 0);
 687
 688         nilfs_btree_free_path(path);
 689
 690         return ret;
 691 }
 692
 693 static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree,
 694                                      __u64 key, __u64 *ptrp,
 695                                      unsigned int maxblocks)
 696 {
 697         struct nilfs_btree_path *path;
 698         struct nilfs_btree_node *node;
 699         struct inode *dat = NULL;
 700         __u64 ptr, ptr2;
 701         sector_t blocknr;
 702         int level = NILFS_BTREE_LEVEL_NODE_MIN;
 703         int ret, cnt, index, maxlevel, ncmax;
 704         struct nilfs_btree_readahead_info p;
 705
 706         path = nilfs_btree_alloc_path();
 707         if (path == NULL)
 708                 return -ENOMEM;
 709
 710         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level, 1);
 711         if (ret < 0)
 712                 goto out;
 713
 714         if (NILFS_BMAP_USE_VBN(btree)) {
 715                 dat = nilfs_bmap_get_dat(btree);
 716                 ret = nilfs_dat_translate(dat, ptr, &blocknr);
 717                 if (ret < 0)
 718                         goto out;
 719                 ptr = blocknr;
 720         }
 721         cnt = 1;
 722         if (cnt == maxblocks)
 723                 goto end;
 724
 725         maxlevel = nilfs_btree_height(btree) - 1;
 726         node = nilfs_btree_get_node(btree, path, level, &ncmax);
 727         index = path[level].bp_index + 1;
 728         for (;;) {
 729                 while (index < nilfs_btree_node_get_nchildren(node)) {
 730                         if (nilfs_btree_node_get_key(node, index) !=
 731                             key + cnt)
 732                                 goto end;
 733                         ptr2 = nilfs_btree_node_get_ptr(node, index, ncmax);
 734                         if (dat) {
 735                                 ret = nilfs_dat_translate(dat, ptr2, &blocknr);
 736                                 if (ret < 0)
 737                                         goto out;
 738                                 ptr2 = blocknr;
 739                         }
 740                         if (ptr2 != ptr + cnt || ++cnt == maxblocks)
 741                                 goto end;
 742                         index++;
 743                 }
 744                 if (level == maxlevel)
 745                         break;
 746
 747                 /* look-up right sibling node */
 748                 p.node = nilfs_btree_get_node(btree, path, level + 1, &p.ncmax);
 749                 p.index = path[level + 1].bp_index + 1;
 750                 p.max_ra_blocks = 7;
 751                 if (p.index >= nilfs_btree_node_get_nchildren(p.node) ||
 752                     nilfs_btree_node_get_key(p.node, p.index) != key + cnt)
 753                         break;
 754                 ptr2 = nilfs_btree_node_get_ptr(p.node, p.index, p.ncmax);
 755                 path[level + 1].bp_index = p.index;
 756
 757                 brelse(path[level].bp_bh);
 758                 path[level].bp_bh = NULL;
 759
 760                 ret = __nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh,
 761                                               &p);
 762                 if (ret < 0)
 763                         goto out;
 764                 node = nilfs_btree_get_nonroot_node(path, level);
 765                 ncmax = nilfs_btree_nchildren_per_block(btree);
 766                 index = 0;
 767                 path[level].bp_index = index;
 768         }
 769  end:
 770         *ptrp = ptr;
 771         ret = cnt;
 772  out:
 773         nilfs_btree_free_path(path);
 774         return ret;
 775 }
 776
 777 static void nilfs_btree_promote_key(struct nilfs_bmap *btree,
 778                                     struct nilfs_btree_path *path,
 779                                     int level, __u64 key)
 780 {
 781         if (level < nilfs_btree_height(btree) - 1) {
 782                 do {
 783                         nilfs_btree_node_set_key(
 784                                 nilfs_btree_get_nonroot_node(path, level),
 785                                 path[level].bp_index, key);
 786                         if (!buffer_dirty(path[level].bp_bh))
 787                                 mark_buffer_dirty(path[level].bp_bh);
 788                 } while ((path[level].bp_index == 0) &&
 789                          (++level < nilfs_btree_height(btree) - 1));
 790         }
 791
 792         /* root */
 793         if (level == nilfs_btree_height(btree) - 1) {
 794                 nilfs_btree_node_set_key(nilfs_btree_get_root(btree),
 795                                          path[level].bp_index, key);
 796         }
 797 }
 798
 799 static void nilfs_btree_do_insert(struct nilfs_bmap *btree,
 800                                   struct nilfs_btree_path *path,
 801                                   int level, __u64 *keyp, __u64 *ptrp)
 802 {
 803         struct nilfs_btree_node *node;
 804         int ncblk;
 805
 806         if (level < nilfs_btree_height(btree) - 1) {
 807                 node = nilfs_btree_get_nonroot_node(path, level);
 808                 ncblk = nilfs_btree_nchildren_per_block(btree);
 809                 nilfs_btree_node_insert(node, path[level].bp_index,
 810                                         *keyp, *ptrp, ncblk);
 811                 if (!buffer_dirty(path[level].bp_bh))
 812                         mark_buffer_dirty(path[level].bp_bh);
 813
 814                 if (path[level].bp_index == 0)
 815                         nilfs_btree_promote_key(btree, path, level + 1,
 816                                                 nilfs_btree_node_get_key(node,
 817                                                                          0));
 818         } else {
 819                 node = nilfs_btree_get_root(btree);
 820                 nilfs_btree_node_insert(node, path[level].bp_index,
 821                                         *keyp, *ptrp,
 822                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
 823         }
 824 }
 825
 826 static void nilfs_btree_carry_left(struct nilfs_bmap *btree,
 827                                    struct nilfs_btree_path *path,
 828                                    int level, __u64 *keyp, __u64 *ptrp)
 829 {
 830         struct nilfs_btree_node *node, *left;
 831         int nchildren, lnchildren, n, move, ncblk;
 832
 833         node = nilfs_btree_get_nonroot_node(path, level);
 834         left = nilfs_btree_get_sib_node(path, level);
 835         nchildren = nilfs_btree_node_get_nchildren(node);
 836         lnchildren = nilfs_btree_node_get_nchildren(left);
 837         ncblk = nilfs_btree_nchildren_per_block(btree);
 838         move = 0;
 839
 840         n = (nchildren + lnchildren + 1) / 2 - lnchildren;
 841         if (n > path[level].bp_index) {
 842                 /* move insert point */
 843                 n--;
 844                 move = 1;
 845         }
 846
 847         nilfs_btree_node_move_left(left, node, n, ncblk, ncblk);
 848
 849         if (!buffer_dirty(path[level].bp_bh))
 850                 mark_buffer_dirty(path[level].bp_bh);
 851         if (!buffer_dirty(path[level].bp_sib_bh))
 852                 mark_buffer_dirty(path[level].bp_sib_bh);
 853
 854         nilfs_btree_promote_key(btree, path, level + 1,
 855                                 nilfs_btree_node_get_key(node, 0));
 856
 857         if (move) {
 858                 brelse(path[level].bp_bh);
 859                 path[level].bp_bh = path[level].bp_sib_bh;
 860                 path[level].bp_sib_bh = NULL;
 861                 path[level].bp_index += lnchildren;
 862                 path[level + 1].bp_index--;
 863         } else {
 864                 brelse(path[level].bp_sib_bh);
 865                 path[level].bp_sib_bh = NULL;
 866                 path[level].bp_index -= n;
 867         }
 868
 869         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 870 }
 871
 872 static void nilfs_btree_carry_right(struct nilfs_bmap *btree,
 873                                     struct nilfs_btree_path *path,
 874                                     int level, __u64 *keyp, __u64 *ptrp)
 875 {
 876         struct nilfs_btree_node *node, *right;
 877         int nchildren, rnchildren, n, move, ncblk;
 878
 879         node = nilfs_btree_get_nonroot_node(path, level);
 880         right = nilfs_btree_get_sib_node(path, level);
 881         nchildren = nilfs_btree_node_get_nchildren(node);
 882         rnchildren = nilfs_btree_node_get_nchildren(right);
 883         ncblk = nilfs_btree_nchildren_per_block(btree);
 884         move = 0;
 885
 886         n = (nchildren + rnchildren + 1) / 2 - rnchildren;
 887         if (n > nchildren - path[level].bp_index) {
 888                 /* move insert point */
 889                 n--;
 890                 move = 1;
 891         }
 892
 893         nilfs_btree_node_move_right(node, right, n, ncblk, ncblk);
 894
 895         if (!buffer_dirty(path[level].bp_bh))
 896                 mark_buffer_dirty(path[level].bp_bh);
 897         if (!buffer_dirty(path[level].bp_sib_bh))
 898                 mark_buffer_dirty(path[level].bp_sib_bh);
 899
 900         path[level + 1].bp_index++;
 901         nilfs_btree_promote_key(btree, path, level + 1,
 902                                 nilfs_btree_node_get_key(right, 0));
 903         path[level + 1].bp_index--;
 904
 905         if (move) {
 906                 brelse(path[level].bp_bh);
 907                 path[level].bp_bh = path[level].bp_sib_bh;
 908                 path[level].bp_sib_bh = NULL;
 909                 path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
 910                 path[level + 1].bp_index++;
 911         } else {
 912                 brelse(path[level].bp_sib_bh);
 913                 path[level].bp_sib_bh = NULL;
 914         }
 915
 916         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 917 }
 918
 919 static void nilfs_btree_split(struct nilfs_bmap *btree,
 920                               struct nilfs_btree_path *path,
 921                               int level, __u64 *keyp, __u64 *ptrp)
 922 {
 923         struct nilfs_btree_node *node, *right;
 924         int nchildren, n, move, ncblk;
 925
 926         node = nilfs_btree_get_nonroot_node(path, level);
 927         right = nilfs_btree_get_sib_node(path, level);
 928         nchildren = nilfs_btree_node_get_nchildren(node);
 929         ncblk = nilfs_btree_nchildren_per_block(btree);
 930         move = 0;
 931
 932         n = (nchildren + 1) / 2;
 933         if (n > nchildren - path[level].bp_index) {
 934                 n--;
 935                 move = 1;
 936         }
 937
 938         nilfs_btree_node_move_right(node, right, n, ncblk, ncblk);
 939
 940         if (!buffer_dirty(path[level].bp_bh))
 941                 mark_buffer_dirty(path[level].bp_bh);
 942         if (!buffer_dirty(path[level].bp_sib_bh))
 943                 mark_buffer_dirty(path[level].bp_sib_bh);
 944
 945         if (move) {
 946                 path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
 947                 nilfs_btree_node_insert(right, path[level].bp_index,
 948                                         *keyp, *ptrp, ncblk);
 949
 950                 *keyp = nilfs_btree_node_get_key(right, 0);
 951                 *ptrp = path[level].bp_newreq.bpr_ptr;
 952
 953                 brelse(path[level].bp_bh);
 954                 path[level].bp_bh = path[level].bp_sib_bh;
 955                 path[level].bp_sib_bh = NULL;
 956         } else {
 957                 nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 958
 959                 *keyp = nilfs_btree_node_get_key(right, 0);
 960                 *ptrp = path[level].bp_newreq.bpr_ptr;
 961
 962                 brelse(path[level].bp_sib_bh);
 963                 path[level].bp_sib_bh = NULL;
 964         }
 965
 966         path[level + 1].bp_index++;
 967 }
 968
 969 static void nilfs_btree_grow(struct nilfs_bmap *btree,
 970                              struct nilfs_btree_path *path,
 971                              int level, __u64 *keyp, __u64 *ptrp)
 972 {
 973         struct nilfs_btree_node *root, *child;
 974         int n, ncblk;
 975
 976         root = nilfs_btree_get_root(btree);
 977         child = nilfs_btree_get_sib_node(path, level);
 978         ncblk = nilfs_btree_nchildren_per_block(btree);
 979
 980         n = nilfs_btree_node_get_nchildren(root);
 981
 982         nilfs_btree_node_move_right(root, child, n,
 983                                     NILFS_BTREE_ROOT_NCHILDREN_MAX, ncblk);
 984         nilfs_btree_node_set_level(root, level + 1);
 985
 986         if (!buffer_dirty(path[level].bp_sib_bh))
 987                 mark_buffer_dirty(path[level].bp_sib_bh);
 988
 989         path[level].bp_bh = path[level].bp_sib_bh;
 990         path[level].bp_sib_bh = NULL;
 991
 992         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 993
 994         *keyp = nilfs_btree_node_get_key(child, 0);
 995         *ptrp = path[level].bp_newreq.bpr_ptr;
 996 }
 997
 998 static __u64 nilfs_btree_find_near(const struct nilfs_bmap *btree,
 999                                    const struct nilfs_btree_path *path)
1000 {
1001         struct nilfs_btree_node *node;
1002         int level, ncmax;
1003
1004         if (path == NULL)
1005                 return NILFS_BMAP_INVALID_PTR;
1006
1007         /* left sibling */
1008         level = NILFS_BTREE_LEVEL_NODE_MIN;
1009         if (path[level].bp_index > 0) {
1010                 node = nilfs_btree_get_node(btree, path, level, &ncmax);
1011                 return nilfs_btree_node_get_ptr(node,
1012                                                 path[level].bp_index - 1,
1013                                                 ncmax);
1014         }
1015
1016         /* parent */
1017         level = NILFS_BTREE_LEVEL_NODE_MIN + 1;
1018         if (level <= nilfs_btree_height(btree) - 1) {
1019                 node = nilfs_btree_get_node(btree, path, level, &ncmax);
1020                 return nilfs_btree_node_get_ptr(node, path[level].bp_index,
1021                                                 ncmax);
1022         }
1023
1024         return NILFS_BMAP_INVALID_PTR;
1025 }
1026
1027 static __u64 nilfs_btree_find_target_v(const struct nilfs_bmap *btree,
1028                                        const struct nilfs_btree_path *path,
1029                                        __u64 key)
1030 {
1031         __u64 ptr;
1032
1033         ptr = nilfs_bmap_find_target_seq(btree, key);
1034         if (ptr != NILFS_BMAP_INVALID_PTR)
1035                 /* sequential access */
1036                 return ptr;
1037
1038         ptr = nilfs_btree_find_near(btree, path);
1039         if (ptr != NILFS_BMAP_INVALID_PTR)
1040                 /* near */
1041                 return ptr;
1042
1043         /* block group */
1044         return nilfs_bmap_find_target_in_group(btree);
1045 }
1046
1047 static int nilfs_btree_prepare_insert(struct nilfs_bmap *btree,
1048                                       struct nilfs_btree_path *path,
1049                                       int *levelp, __u64 key, __u64 ptr,
1050                                       struct nilfs_bmap_stats *stats)
1051 {
1052         struct buffer_head *bh;
1053         struct nilfs_btree_node *node, *parent, *sib;
1054         __u64 sibptr;
1055         int pindex, level, ncmax, ncblk, ret;
1056         struct inode *dat = NULL;
1057
1058         stats->bs_nblocks = 0;
1059         level = NILFS_BTREE_LEVEL_DATA;
1060
1061         /* allocate a new ptr for data block */
1062         if (NILFS_BMAP_USE_VBN(btree)) {
1063                 path[level].bp_newreq.bpr_ptr =
1064                         nilfs_btree_find_target_v(btree, path, key);
1065                 dat = nilfs_bmap_get_dat(btree);
1066         }
1067
1068         ret = nilfs_bmap_prepare_alloc_ptr(btree, &path[level].bp_newreq, dat);
1069         if (ret < 0)
1070                 goto err_out_data;
1071
1072         ncblk = nilfs_btree_nchildren_per_block(btree);
1073
1074         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
1075              level < nilfs_btree_height(btree) - 1;
1076              level++) {
1077                 node = nilfs_btree_get_nonroot_node(path, level);
1078                 if (nilfs_btree_node_get_nchildren(node) < ncblk) {
1079                         path[level].bp_op = nilfs_btree_do_insert;
1080                         stats->bs_nblocks++;
1081                         goto out;
1082                 }
1083
1084                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1085                 pindex = path[level + 1].bp_index;
1086
1087                 /* left sibling */
1088                 if (pindex > 0) {
1089                         sibptr = nilfs_btree_node_get_ptr(parent, pindex - 1,
1090                                                           ncmax);
1091                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1092                         if (ret < 0)
1093                                 goto err_out_child_node;
1094                         sib = (struct nilfs_btree_node *)bh->b_data;
1095                         if (nilfs_btree_node_get_nchildren(sib) < ncblk) {
1096                                 path[level].bp_sib_bh = bh;
1097                                 path[level].bp_op = nilfs_btree_carry_left;
1098                                 stats->bs_nblocks++;
1099                                 goto out;
1100                         } else {
1101                                 brelse(bh);
1102                         }
1103                 }
1104
1105                 /* right sibling */
1106                 if (pindex < nilfs_btree_node_get_nchildren(parent) - 1) {
1107                         sibptr = nilfs_btree_node_get_ptr(parent, pindex + 1,
1108                                                           ncmax);
1109                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1110                         if (ret < 0)
1111                                 goto err_out_child_node;
1112                         sib = (struct nilfs_btree_node *)bh->b_data;
1113                         if (nilfs_btree_node_get_nchildren(sib) < ncblk) {
1114                                 path[level].bp_sib_bh = bh;
1115                                 path[level].bp_op = nilfs_btree_carry_right;
1116                                 stats->bs_nblocks++;
1117                                 goto out;
1118                         } else {
1119                                 brelse(bh);
1120                         }
1121                 }
1122
1123                 /* split */
1124                 path[level].bp_newreq.bpr_ptr =
1125                         path[level - 1].bp_newreq.bpr_ptr + 1;
1126                 ret = nilfs_bmap_prepare_alloc_ptr(btree,
1127                                                    &path[level].bp_newreq, dat);
1128                 if (ret < 0)
1129                         goto err_out_child_node;
1130                 ret = nilfs_btree_get_new_block(btree,
1131                                                 path[level].bp_newreq.bpr_ptr,
1132                                                 &bh);
1133                 if (ret < 0)
1134                         goto err_out_curr_node;
1135
1136                 stats->bs_nblocks++;
1137
1138                 sib = (struct nilfs_btree_node *)bh->b_data;
1139                 nilfs_btree_node_init(sib, 0, level, 0, ncblk, NULL, NULL);
1140                 path[level].bp_sib_bh = bh;
1141                 path[level].bp_op = nilfs_btree_split;
1142         }
1143
1144         /* root */
1145         node = nilfs_btree_get_root(btree);
1146         if (nilfs_btree_node_get_nchildren(node) <
1147             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1148                 path[level].bp_op = nilfs_btree_do_insert;
1149                 stats->bs_nblocks++;
1150                 goto out;
1151         }
1152
1153         /* grow */
1154         path[level].bp_newreq.bpr_ptr = path[level - 1].bp_newreq.bpr_ptr + 1;
1155         ret = nilfs_bmap_prepare_alloc_ptr(btree, &path[level].bp_newreq, dat);
1156         if (ret < 0)
1157                 goto err_out_child_node;
1158         ret = nilfs_btree_get_new_block(btree, path[level].bp_newreq.bpr_ptr,
1159                                         &bh);
1160         if (ret < 0)
1161                 goto err_out_curr_node;
1162
1163         nilfs_btree_node_init((struct nilfs_btree_node *)bh->b_data,
1164                               0, level, 0, ncblk, NULL, NULL);
1165         path[level].bp_sib_bh = bh;
1166         path[level].bp_op = nilfs_btree_grow;
1167
1168         level++;
1169         path[level].bp_op = nilfs_btree_do_insert;
1170
1171         /* a newly-created node block and a data block are added */
1172         stats->bs_nblocks += 2;
1173
1174         /* success */
1175  out:
1176         *levelp = level;
1177         return ret;
1178
1179         /* error */
1180  err_out_curr_node:
1181         nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1182  err_out_child_node:
1183         for (level--; level > NILFS_BTREE_LEVEL_DATA; level--) {
1184                 nilfs_btnode_delete(path[level].bp_sib_bh);
1185                 nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1186
1187         }
1188
1189         nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1190  err_out_data:
1191         *levelp = level;
1192         stats->bs_nblocks = 0;
1193         return ret;
1194 }
1195
1196 static void nilfs_btree_commit_insert(struct nilfs_bmap *btree,
1197                                       struct nilfs_btree_path *path,
1198                                       int maxlevel, __u64 key, __u64 ptr)
1199 {
1200         struct inode *dat = NULL;
1201         int level;
1202
1203         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
1204         ptr = path[NILFS_BTREE_LEVEL_DATA].bp_newreq.bpr_ptr;
1205         if (NILFS_BMAP_USE_VBN(btree)) {
1206                 nilfs_bmap_set_target_v(btree, key, ptr);
1207                 dat = nilfs_bmap_get_dat(btree);
1208         }
1209
1210         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
1211                 nilfs_bmap_commit_alloc_ptr(btree,
1212                                             &path[level - 1].bp_newreq, dat);
1213                 path[level].bp_op(btree, path, level, &key, &ptr);
1214         }
1215
1216         if (!nilfs_bmap_dirty(btree))
1217                 nilfs_bmap_set_dirty(btree);
1218 }
1219
1220 static int nilfs_btree_insert(struct nilfs_bmap *btree, __u64 key, __u64 ptr)
1221 {
1222         struct nilfs_btree_path *path;
1223         struct nilfs_bmap_stats stats;
1224         int level, ret;
1225
1226         path = nilfs_btree_alloc_path();
1227         if (path == NULL)
1228                 return -ENOMEM;
1229
1230         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
1231                                     NILFS_BTREE_LEVEL_NODE_MIN, 0);
1232         if (ret != -ENOENT) {
1233                 if (ret == 0)
1234                         ret = -EEXIST;
1235                 goto out;
1236         }
1237
1238         ret = nilfs_btree_prepare_insert(btree, path, &level, key, ptr, &stats);
1239         if (ret < 0)
1240                 goto out;
1241         nilfs_btree_commit_insert(btree, path, level, key, ptr);
1242         nilfs_inode_add_blocks(btree->b_inode, stats.bs_nblocks);
1243
1244  out:
1245         nilfs_btree_free_path(path);
1246         return ret;
1247 }
1248
1249 static void nilfs_btree_do_delete(struct nilfs_bmap *btree,
1250                                   struct nilfs_btree_path *path,
1251                                   int level, __u64 *keyp, __u64 *ptrp)
1252 {
1253         struct nilfs_btree_node *node;
1254         int ncblk;
1255
1256         if (level < nilfs_btree_height(btree) - 1) {
1257                 node = nilfs_btree_get_nonroot_node(path, level);
1258                 ncblk = nilfs_btree_nchildren_per_block(btree);
1259                 nilfs_btree_node_delete(node, path[level].bp_index,
1260                                         keyp, ptrp, ncblk);
1261                 if (!buffer_dirty(path[level].bp_bh))
1262                         mark_buffer_dirty(path[level].bp_bh);
1263                 if (path[level].bp_index == 0)
1264                         nilfs_btree_promote_key(btree, path, level + 1,
1265                                 nilfs_btree_node_get_key(node, 0));
1266         } else {
1267                 node = nilfs_btree_get_root(btree);
1268                 nilfs_btree_node_delete(node, path[level].bp_index,
1269                                         keyp, ptrp,
1270                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
1271         }
1272 }
1273
1274 static void nilfs_btree_borrow_left(struct nilfs_bmap *btree,
1275                                     struct nilfs_btree_path *path,
1276                                     int level, __u64 *keyp, __u64 *ptrp)
1277 {
1278         struct nilfs_btree_node *node, *left;
1279         int nchildren, lnchildren, n, ncblk;
1280
1281         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1282
1283         node = nilfs_btree_get_nonroot_node(path, level);
1284         left = nilfs_btree_get_sib_node(path, level);
1285         nchildren = nilfs_btree_node_get_nchildren(node);
1286         lnchildren = nilfs_btree_node_get_nchildren(left);
1287         ncblk = nilfs_btree_nchildren_per_block(btree);
1288
1289         n = (nchildren + lnchildren) / 2 - nchildren;
1290
1291         nilfs_btree_node_move_right(left, node, n, ncblk, ncblk);
1292
1293         if (!buffer_dirty(path[level].bp_bh))
1294                 mark_buffer_dirty(path[level].bp_bh);
1295         if (!buffer_dirty(path[level].bp_sib_bh))
1296                 mark_buffer_dirty(path[level].bp_sib_bh);
1297
1298         nilfs_btree_promote_key(btree, path, level + 1,
1299                                 nilfs_btree_node_get_key(node, 0));
1300
1301         brelse(path[level].bp_sib_bh);
1302         path[level].bp_sib_bh = NULL;
1303         path[level].bp_index += n;
1304 }
1305
1306 static void nilfs_btree_borrow_right(struct nilfs_bmap *btree,
1307                                      struct nilfs_btree_path *path,
1308                                      int level, __u64 *keyp, __u64 *ptrp)
1309 {
1310         struct nilfs_btree_node *node, *right;
1311         int nchildren, rnchildren, n, ncblk;
1312
1313         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1314
1315         node = nilfs_btree_get_nonroot_node(path, level);
1316         right = nilfs_btree_get_sib_node(path, level);
1317         nchildren = nilfs_btree_node_get_nchildren(node);
1318         rnchildren = nilfs_btree_node_get_nchildren(right);
1319         ncblk = nilfs_btree_nchildren_per_block(btree);
1320
1321         n = (nchildren + rnchildren) / 2 - nchildren;
1322
1323         nilfs_btree_node_move_left(node, right, n, ncblk, ncblk);
1324
1325         if (!buffer_dirty(path[level].bp_bh))
1326                 mark_buffer_dirty(path[level].bp_bh);
1327         if (!buffer_dirty(path[level].bp_sib_bh))
1328                 mark_buffer_dirty(path[level].bp_sib_bh);
1329
1330         path[level + 1].bp_index++;
1331         nilfs_btree_promote_key(btree, path, level + 1,
1332                                 nilfs_btree_node_get_key(right, 0));
1333         path[level + 1].bp_index--;
1334
1335         brelse(path[level].bp_sib_bh);
1336         path[level].bp_sib_bh = NULL;
1337 }
1338
1339 static void nilfs_btree_concat_left(struct nilfs_bmap *btree,
1340                                     struct nilfs_btree_path *path,
1341                                     int level, __u64 *keyp, __u64 *ptrp)
1342 {
1343         struct nilfs_btree_node *node, *left;
1344         int n, ncblk;
1345
1346         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1347
1348         node = nilfs_btree_get_nonroot_node(path, level);
1349         left = nilfs_btree_get_sib_node(path, level);
1350         ncblk = nilfs_btree_nchildren_per_block(btree);
1351
1352         n = nilfs_btree_node_get_nchildren(node);
1353
1354         nilfs_btree_node_move_left(left, node, n, ncblk, ncblk);
1355
1356         if (!buffer_dirty(path[level].bp_sib_bh))
1357                 mark_buffer_dirty(path[level].bp_sib_bh);
1358
1359         nilfs_btnode_delete(path[level].bp_bh);
1360         path[level].bp_bh = path[level].bp_sib_bh;
1361         path[level].bp_sib_bh = NULL;
1362         path[level].bp_index += nilfs_btree_node_get_nchildren(left);
1363 }
1364
1365 static void nilfs_btree_concat_right(struct nilfs_bmap *btree,
1366                                      struct nilfs_btree_path *path,
1367                                      int level, __u64 *keyp, __u64 *ptrp)
1368 {
1369         struct nilfs_btree_node *node, *right;
1370         int n, ncblk;
1371
1372         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1373
1374         node = nilfs_btree_get_nonroot_node(path, level);
1375         right = nilfs_btree_get_sib_node(path, level);
1376         ncblk = nilfs_btree_nchildren_per_block(btree);
1377
1378         n = nilfs_btree_node_get_nchildren(right);
1379
1380         nilfs_btree_node_move_left(node, right, n, ncblk, ncblk);
1381
1382         if (!buffer_dirty(path[level].bp_bh))
1383                 mark_buffer_dirty(path[level].bp_bh);
1384
1385         nilfs_btnode_delete(path[level].bp_sib_bh);
1386         path[level].bp_sib_bh = NULL;
1387         path[level + 1].bp_index++;
1388 }
1389
1390 static void nilfs_btree_shrink(struct nilfs_bmap *btree,
1391                                struct nilfs_btree_path *path,
1392                                int level, __u64 *keyp, __u64 *ptrp)
1393 {
1394         struct nilfs_btree_node *root, *child;
1395         int n, ncblk;
1396
1397         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1398
1399         root = nilfs_btree_get_root(btree);
1400         child = nilfs_btree_get_nonroot_node(path, level);
1401         ncblk = nilfs_btree_nchildren_per_block(btree);
1402
1403         nilfs_btree_node_delete(root, 0, NULL, NULL,
1404                                 NILFS_BTREE_ROOT_NCHILDREN_MAX);
1405         nilfs_btree_node_set_level(root, level);
1406         n = nilfs_btree_node_get_nchildren(child);
1407         nilfs_btree_node_move_left(root, child, n,
1408                                    NILFS_BTREE_ROOT_NCHILDREN_MAX, ncblk);
1409
1410         nilfs_btnode_delete(path[level].bp_bh);
1411         path[level].bp_bh = NULL;
1412 }
1413
1414 static void nilfs_btree_nop(struct nilfs_bmap *btree,
1415                             struct nilfs_btree_path *path,
1416                             int level, __u64 *keyp, __u64 *ptrp)
1417 {
1418 }
1419
1420 static int nilfs_btree_prepare_delete(struct nilfs_bmap *btree,
1421                                       struct nilfs_btree_path *path,
1422                                       int *levelp,
1423                                       struct nilfs_bmap_stats *stats,
1424                                       struct inode *dat)
1425 {
1426         struct buffer_head *bh;
1427         struct nilfs_btree_node *node, *parent, *sib;
1428         __u64 sibptr;
1429         int pindex, dindex, level, ncmin, ncmax, ncblk, ret;
1430
1431         ret = 0;
1432         stats->bs_nblocks = 0;
1433         ncmin = NILFS_BTREE_NODE_NCHILDREN_MIN(nilfs_btree_node_size(btree));
1434         ncblk = nilfs_btree_nchildren_per_block(btree);
1435
1436         for (level = NILFS_BTREE_LEVEL_NODE_MIN, dindex = path[level].bp_index;
1437              level < nilfs_btree_height(btree) - 1;
1438              level++) {
1439                 node = nilfs_btree_get_nonroot_node(path, level);
1440                 path[level].bp_oldreq.bpr_ptr =
1441                         nilfs_btree_node_get_ptr(node, dindex, ncblk);
1442                 ret = nilfs_bmap_prepare_end_ptr(btree,
1443                                                  &path[level].bp_oldreq, dat);
1444                 if (ret < 0)
1445                         goto err_out_child_node;
1446
1447                 if (nilfs_btree_node_get_nchildren(node) > ncmin) {
1448                         path[level].bp_op = nilfs_btree_do_delete;
1449                         stats->bs_nblocks++;
1450                         goto out;
1451                 }
1452
1453                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1454                 pindex = path[level + 1].bp_index;
1455                 dindex = pindex;
1456
1457                 if (pindex > 0) {
1458                         /* left sibling */
1459                         sibptr = nilfs_btree_node_get_ptr(parent, pindex - 1,
1460                                                           ncmax);
1461                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1462                         if (ret < 0)
1463                                 goto err_out_curr_node;
1464                         sib = (struct nilfs_btree_node *)bh->b_data;
1465                         if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
1466                                 path[level].bp_sib_bh = bh;
1467                                 path[level].bp_op = nilfs_btree_borrow_left;
1468                                 stats->bs_nblocks++;
1469                                 goto out;
1470                         } else {
1471                                 path[level].bp_sib_bh = bh;
1472                                 path[level].bp_op = nilfs_btree_concat_left;
1473                                 stats->bs_nblocks++;
1474                                 /* continue; */
1475                         }
1476                 } else if (pindex <
1477                            nilfs_btree_node_get_nchildren(parent) - 1) {
1478                         /* right sibling */
1479                         sibptr = nilfs_btree_node_get_ptr(parent, pindex + 1,
1480                                                           ncmax);
1481                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1482                         if (ret < 0)
1483                                 goto err_out_curr_node;
1484                         sib = (struct nilfs_btree_node *)bh->b_data;
1485                         if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
1486                                 path[level].bp_sib_bh = bh;
1487                                 path[level].bp_op = nilfs_btree_borrow_right;
1488                                 stats->bs_nblocks++;
1489                                 goto out;
1490                         } else {
1491                                 path[level].bp_sib_bh = bh;
1492                                 path[level].bp_op = nilfs_btree_concat_right;
1493                                 stats->bs_nblocks++;
1494                                 /*
1495                                  * When merging right sibling node
1496                                  * into the current node, pointer to
1497                                  * the right sibling node must be
1498                                  * terminated instead.  The adjustment
1499                                  * below is required for that.
1500                                  */
1501                                 dindex = pindex + 1;
1502                                 /* continue; */
1503                         }
1504                 } else {
1505                         /* no siblings */
1506                         /* the only child of the root node */
1507                         WARN_ON(level != nilfs_btree_height(btree) - 2);
1508                         if (nilfs_btree_node_get_nchildren(node) - 1 <=
1509                             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1510                                 path[level].bp_op = nilfs_btree_shrink;
1511                                 stats->bs_nblocks += 2;
1512                                 level++;
1513                                 path[level].bp_op = nilfs_btree_nop;
1514                                 goto shrink_root_child;
1515                         } else {
1516                                 path[level].bp_op = nilfs_btree_do_delete;
1517                                 stats->bs_nblocks++;
1518                                 goto out;
1519                         }
1520                 }
1521         }
1522
1523         /* child of the root node is deleted */
1524         path[level].bp_op = nilfs_btree_do_delete;
1525         stats->bs_nblocks++;
1526
1527 shrink_root_child:
1528         node = nilfs_btree_get_root(btree);
1529         path[level].bp_oldreq.bpr_ptr =
1530                 nilfs_btree_node_get_ptr(node, dindex,
1531                                          NILFS_BTREE_ROOT_NCHILDREN_MAX);
1532
1533         ret = nilfs_bmap_prepare_end_ptr(btree, &path[level].bp_oldreq, dat);
1534         if (ret < 0)
1535                 goto err_out_child_node;
1536
1537         /* success */
1538  out:
1539         *levelp = level;
1540         return ret;
1541
1542         /* error */
1543  err_out_curr_node:
1544         nilfs_bmap_abort_end_ptr(btree, &path[level].bp_oldreq, dat);
1545  err_out_child_node:
1546         for (level--; level >= NILFS_BTREE_LEVEL_NODE_MIN; level--) {
1547                 brelse(path[level].bp_sib_bh);
1548                 nilfs_bmap_abort_end_ptr(btree, &path[level].bp_oldreq, dat);
1549         }
1550         *levelp = level;
1551         stats->bs_nblocks = 0;
1552         return ret;
1553 }
1554
1555 static void nilfs_btree_commit_delete(struct nilfs_bmap *btree,
1556                                       struct nilfs_btree_path *path,
1557                                       int maxlevel, struct inode *dat)
1558 {
1559         int level;
1560
1561         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
1562                 nilfs_bmap_commit_end_ptr(btree, &path[level].bp_oldreq, dat);
1563                 path[level].bp_op(btree, path, level, NULL, NULL);
1564         }
1565
1566         if (!nilfs_bmap_dirty(btree))
1567                 nilfs_bmap_set_dirty(btree);
1568 }
1569
1570 static int nilfs_btree_delete(struct nilfs_bmap *btree, __u64 key)
1571
1572 {
1573         struct nilfs_btree_path *path;
1574         struct nilfs_bmap_stats stats;
1575         struct inode *dat;
1576         int level, ret;
1577
1578         path = nilfs_btree_alloc_path();
1579         if (path == NULL)
1580                 return -ENOMEM;
1581
1582         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
1583                                     NILFS_BTREE_LEVEL_NODE_MIN, 0);
1584         if (ret < 0)
1585                 goto out;
1586
1587
1588         dat = NILFS_BMAP_USE_VBN(btree) ? nilfs_bmap_get_dat(btree) : NULL;
1589
1590         ret = nilfs_btree_prepare_delete(btree, path, &level, &stats, dat);
1591         if (ret < 0)
1592                 goto out;
1593         nilfs_btree_commit_delete(btree, path, level, dat);
1594         nilfs_inode_sub_blocks(btree->b_inode, stats.bs_nblocks);
1595
1596 out:
1597         nilfs_btree_free_path(path);
1598         return ret;
1599 }
1600
1601 static int nilfs_btree_seek_key(const struct nilfs_bmap *btree, __u64 start,
1602                                 __u64 *keyp)
1603 {
1604         struct nilfs_btree_path *path;
1605         const int minlevel = NILFS_BTREE_LEVEL_NODE_MIN;
1606         int ret;
1607
1608         path = nilfs_btree_alloc_path();
1609         if (!path)
1610                 return -ENOMEM;
1611
1612         ret = nilfs_btree_do_lookup(btree, path, start, NULL, minlevel, 0);
1613         if (!ret)
1614                 *keyp = start;
1615         else if (ret == -ENOENT)
1616                 ret = nilfs_btree_get_next_key(btree, path, minlevel, keyp);
1617
1618         nilfs_btree_free_path(path);
1619         return ret;
1620 }
1621
1622 static int nilfs_btree_last_key(const struct nilfs_bmap *btree, __u64 *keyp)
1623 {
1624         struct nilfs_btree_path *path;
1625         int ret;
1626
1627         path = nilfs_btree_alloc_path();
1628         if (path == NULL)
1629                 return -ENOMEM;
1630
1631         ret = nilfs_btree_do_lookup_last(btree, path, keyp, NULL);
1632
1633         nilfs_btree_free_path(path);
1634
1635         return ret;
1636 }
1637
1638 static int nilfs_btree_check_delete(struct nilfs_bmap *btree, __u64 key)
1639 {
1640         struct buffer_head *bh;
1641         struct nilfs_btree_node *root, *node;
1642         __u64 maxkey, nextmaxkey;
1643         __u64 ptr;
1644         int nchildren, ret;
1645
1646         root = nilfs_btree_get_root(btree);
1647         switch (nilfs_btree_height(btree)) {
1648         case 2:
1649                 bh = NULL;
1650                 node = root;
1651                 break;
1652         case 3:
1653                 nchildren = nilfs_btree_node_get_nchildren(root);
1654                 if (nchildren > 1)
1655                         return 0;
1656                 ptr = nilfs_btree_node_get_ptr(root, nchildren - 1,
1657                                                NILFS_BTREE_ROOT_NCHILDREN_MAX);
1658                 ret = nilfs_btree_get_block(btree, ptr, &bh);
1659                 if (ret < 0)
1660                         return ret;
1661                 node = (struct nilfs_btree_node *)bh->b_data;
1662                 break;
1663         default:
1664                 return 0;
1665         }
1666
1667         nchildren = nilfs_btree_node_get_nchildren(node);
1668         maxkey = nilfs_btree_node_get_key(node, nchildren - 1);
1669         nextmaxkey = (nchildren > 1) ?
1670                 nilfs_btree_node_get_key(node, nchildren - 2) : 0;
1671         brelse(bh);
1672
1673         return (maxkey == key) && (nextmaxkey < NILFS_BMAP_LARGE_LOW);
1674 }
1675
1676 static int nilfs_btree_gather_data(struct nilfs_bmap *btree,
1677                                    __u64 *keys, __u64 *ptrs, int nitems)
1678 {
1679         struct buffer_head *bh;
1680         struct nilfs_btree_node *node, *root;
1681         __le64 *dkeys;
1682         __le64 *dptrs;
1683         __u64 ptr;
1684         int nchildren, ncmax, i, ret;
1685
1686         root = nilfs_btree_get_root(btree);
1687         switch (nilfs_btree_height(btree)) {
1688         case 2:
1689                 bh = NULL;
1690                 node = root;
1691                 ncmax = NILFS_BTREE_ROOT_NCHILDREN_MAX;
1692                 break;
1693         case 3:
1694                 nchildren = nilfs_btree_node_get_nchildren(root);
1695                 WARN_ON(nchildren > 1);
1696                 ptr = nilfs_btree_node_get_ptr(root, nchildren - 1,
1697                                                NILFS_BTREE_ROOT_NCHILDREN_MAX);
1698                 ret = nilfs_btree_get_block(btree, ptr, &bh);
1699                 if (ret < 0)
1700                         return ret;
1701                 node = (struct nilfs_btree_node *)bh->b_data;
1702                 ncmax = nilfs_btree_nchildren_per_block(btree);
1703                 break;
1704         default:
1705                 node = NULL;
1706                 return -EINVAL;
1707         }
1708
1709         nchildren = nilfs_btree_node_get_nchildren(node);
1710         if (nchildren < nitems)
1711                 nitems = nchildren;
1712         dkeys = nilfs_btree_node_dkeys(node);
1713         dptrs = nilfs_btree_node_dptrs(node, ncmax);
1714         for (i = 0; i < nitems; i++) {
1715                 keys[i] = le64_to_cpu(dkeys[i]);
1716                 ptrs[i] = le64_to_cpu(dptrs[i]);
1717         }
1718
1719         brelse(bh);
1720
1721         return nitems;
1722 }
1723
1724 static int
1725 nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *btree, __u64 key,
1726                                        union nilfs_bmap_ptr_req *dreq,
1727                                        union nilfs_bmap_ptr_req *nreq,
1728                                        struct buffer_head **bhp,
1729                                        struct nilfs_bmap_stats *stats)
1730 {
1731         struct buffer_head *bh;
1732         struct inode *dat = NULL;
1733         int ret;
1734
1735         stats->bs_nblocks = 0;
1736
1737         /* for data */
1738         /* cannot find near ptr */
1739         if (NILFS_BMAP_USE_VBN(btree)) {
1740                 dreq->bpr_ptr = nilfs_btree_find_target_v(btree, NULL, key);
1741                 dat = nilfs_bmap_get_dat(btree);
1742         }
1743
1744         ret = nilfs_attach_btree_node_cache(&NILFS_BMAP_I(btree)->vfs_inode);
1745         if (ret < 0)
1746                 return ret;
1747
1748         ret = nilfs_bmap_prepare_alloc_ptr(btree, dreq, dat);
1749         if (ret < 0)
1750                 return ret;
1751
1752         *bhp = NULL;
1753         stats->bs_nblocks++;
1754         if (nreq != NULL) {
1755                 nreq->bpr_ptr = dreq->bpr_ptr + 1;
1756                 ret = nilfs_bmap_prepare_alloc_ptr(btree, nreq, dat);
1757                 if (ret < 0)
1758                         goto err_out_dreq;
1759
1760                 ret = nilfs_btree_get_new_block(btree, nreq->bpr_ptr, &bh);
1761                 if (ret < 0)
1762                         goto err_out_nreq;
1763
1764                 *bhp = bh;
1765                 stats->bs_nblocks++;
1766         }
1767
1768         /* success */
1769         return 0;
1770
1771         /* error */
1772  err_out_nreq:
1773         nilfs_bmap_abort_alloc_ptr(btree, nreq, dat);
1774  err_out_dreq:
1775         nilfs_bmap_abort_alloc_ptr(btree, dreq, dat);
1776         stats->bs_nblocks = 0;
1777         return ret;
1778
1779 }
1780
1781 static void
1782 nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *btree,
1783                                       __u64 key, __u64 ptr,
1784                                       const __u64 *keys, const __u64 *ptrs,
1785                                       int n,
1786                                       union nilfs_bmap_ptr_req *dreq,
1787                                       union nilfs_bmap_ptr_req *nreq,
1788                                       struct buffer_head *bh)
1789 {
1790         struct nilfs_btree_node *node;
1791         struct inode *dat;
1792         __u64 tmpptr;
1793         int ncblk;
1794
1795         /* free resources */
1796         if (btree->b_ops->bop_clear != NULL)
1797                 btree->b_ops->bop_clear(btree);
1798
1799         /* ptr must be a pointer to a buffer head. */
1800         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
1801
1802         /* convert and insert */
1803         dat = NILFS_BMAP_USE_VBN(btree) ? nilfs_bmap_get_dat(btree) : NULL;
1804         __nilfs_btree_init(btree);
1805         if (nreq != NULL) {
1806                 nilfs_bmap_commit_alloc_ptr(btree, dreq, dat);
1807                 nilfs_bmap_commit_alloc_ptr(btree, nreq, dat);
1808
1809                 /* create child node at level 1 */
1810                 node = (struct nilfs_btree_node *)bh->b_data;
1811                 ncblk = nilfs_btree_nchildren_per_block(btree);
1812                 nilfs_btree_node_init(node, 0, 1, n, ncblk, keys, ptrs);
1813                 nilfs_btree_node_insert(node, n, key, dreq->bpr_ptr, ncblk);
1814                 if (!buffer_dirty(bh))
1815                         mark_buffer_dirty(bh);
1816                 if (!nilfs_bmap_dirty(btree))
1817                         nilfs_bmap_set_dirty(btree);
1818
1819                 brelse(bh);
1820
1821                 /* create root node at level 2 */
1822                 node = nilfs_btree_get_root(btree);
1823                 tmpptr = nreq->bpr_ptr;
1824                 nilfs_btree_node_init(node, NILFS_BTREE_NODE_ROOT, 2, 1,
1825                                       NILFS_BTREE_ROOT_NCHILDREN_MAX,
1826                                       &keys[0], &tmpptr);
1827         } else {
1828                 nilfs_bmap_commit_alloc_ptr(btree, dreq, dat);
1829
1830                 /* create root node at level 1 */
1831                 node = nilfs_btree_get_root(btree);
1832                 nilfs_btree_node_init(node, NILFS_BTREE_NODE_ROOT, 1, n,
1833                                       NILFS_BTREE_ROOT_NCHILDREN_MAX,
1834                                       keys, ptrs);
1835                 nilfs_btree_node_insert(node, n, key, dreq->bpr_ptr,
1836                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
1837                 if (!nilfs_bmap_dirty(btree))
1838                         nilfs_bmap_set_dirty(btree);
1839         }
1840
1841         if (NILFS_BMAP_USE_VBN(btree))
1842                 nilfs_bmap_set_target_v(btree, key, dreq->bpr_ptr);
1843 }
1844
1845 /**
1846  * nilfs_btree_convert_and_insert -
1847  * @bmap:
1848  * @key:
1849  * @ptr:
1850  * @keys:
1851  * @ptrs:
1852  * @n:
1853  */
1854 int nilfs_btree_convert_and_insert(struct nilfs_bmap *btree,
1855                                    __u64 key, __u64 ptr,
1856                                    const __u64 *keys, const __u64 *ptrs, int n)
1857 {
1858         struct buffer_head *bh = NULL;
1859         union nilfs_bmap_ptr_req dreq, nreq, *di, *ni;
1860         struct nilfs_bmap_stats stats;
1861         int ret;
1862
1863         if (n + 1 <= NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1864                 di = &dreq;
1865                 ni = NULL;
1866         } else if ((n + 1) <= NILFS_BTREE_NODE_NCHILDREN_MAX(
1867                            nilfs_btree_node_size(btree))) {
1868                 di = &dreq;
1869                 ni = &nreq;
1870         } else {
1871                 di = NULL;
1872                 ni = NULL;
1873                 BUG();
1874         }
1875
1876         ret = nilfs_btree_prepare_convert_and_insert(btree, key, di, ni, &bh,
1877                                                      &stats);
1878         if (ret < 0)
1879                 return ret;
1880         nilfs_btree_commit_convert_and_insert(btree, key, ptr, keys, ptrs, n,
1881                                               di, ni, bh);
1882         nilfs_inode_add_blocks(btree->b_inode, stats.bs_nblocks);
1883         return 0;
1884 }
1885
1886 static int nilfs_btree_propagate_p(struct nilfs_bmap *btree,
1887                                    struct nilfs_btree_path *path,
1888                                    int level,
1889                                    struct buffer_head *bh)
1890 {
1891         while ((++level < nilfs_btree_height(btree) - 1) &&
1892                !buffer_dirty(path[level].bp_bh))
1893                 mark_buffer_dirty(path[level].bp_bh);
1894
1895         return 0;
1896 }
1897
1898 static int nilfs_btree_prepare_update_v(struct nilfs_bmap *btree,
1899                                         struct nilfs_btree_path *path,
1900                                         int level, struct inode *dat)
1901 {
1902         struct nilfs_btree_node *parent;
1903         int ncmax, ret;
1904
1905         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1906         path[level].bp_oldreq.bpr_ptr =
1907                 nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
1908                                          ncmax);
1909         path[level].bp_newreq.bpr_ptr = path[level].bp_oldreq.bpr_ptr + 1;
1910         ret = nilfs_dat_prepare_update(dat, &path[level].bp_oldreq.bpr_req,
1911                                        &path[level].bp_newreq.bpr_req);
1912         if (ret < 0)
1913                 return ret;
1914
1915         if (buffer_nilfs_node(path[level].bp_bh)) {
1916                 path[level].bp_ctxt.oldkey = path[level].bp_oldreq.bpr_ptr;
1917                 path[level].bp_ctxt.newkey = path[level].bp_newreq.bpr_ptr;
1918                 path[level].bp_ctxt.bh = path[level].bp_bh;
1919                 ret = nilfs_btnode_prepare_change_key(
1920                         NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
1921                         &path[level].bp_ctxt);
1922                 if (ret < 0) {
1923                         nilfs_dat_abort_update(dat,
1924                                                &path[level].bp_oldreq.bpr_req,
1925                                                &path[level].bp_newreq.bpr_req);
1926                         return ret;
1927                 }
1928         }
1929
1930         return 0;
1931 }
1932
1933 static void nilfs_btree_commit_update_v(struct nilfs_bmap *btree,
1934                                         struct nilfs_btree_path *path,
1935                                         int level, struct inode *dat)
1936 {
1937         struct nilfs_btree_node *parent;
1938         int ncmax;
1939
1940         nilfs_dat_commit_update(dat, &path[level].bp_oldreq.bpr_req,
1941                                 &path[level].bp_newreq.bpr_req,
1942                                 btree->b_ptr_type == NILFS_BMAP_PTR_VS);
1943
1944         if (buffer_nilfs_node(path[level].bp_bh)) {
1945                 nilfs_btnode_commit_change_key(
1946                         NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
1947                         &path[level].bp_ctxt);
1948                 path[level].bp_bh = path[level].bp_ctxt.bh;
1949         }
1950         set_buffer_nilfs_volatile(path[level].bp_bh);
1951
1952         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1953         nilfs_btree_node_set_ptr(parent, path[level + 1].bp_index,
1954                                  path[level].bp_newreq.bpr_ptr, ncmax);
1955 }
1956
1957 static void nilfs_btree_abort_update_v(struct nilfs_bmap *btree,
1958                                        struct nilfs_btree_path *path,
1959                                        int level, struct inode *dat)
1960 {
1961         nilfs_dat_abort_update(dat, &path[level].bp_oldreq.bpr_req,
1962                                &path[level].bp_newreq.bpr_req);
1963         if (buffer_nilfs_node(path[level].bp_bh))
1964                 nilfs_btnode_abort_change_key(
1965                         NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
1966                         &path[level].bp_ctxt);
1967 }
1968
1969 static int nilfs_btree_prepare_propagate_v(struct nilfs_bmap *btree,
1970                                            struct nilfs_btree_path *path,
1971                                            int minlevel, int *maxlevelp,
1972                                            struct inode *dat)
1973 {
1974         int level, ret;
1975
1976         level = minlevel;
1977         if (!buffer_nilfs_volatile(path[level].bp_bh)) {
1978                 ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
1979                 if (ret < 0)
1980                         return ret;
1981         }
1982         while ((++level < nilfs_btree_height(btree) - 1) &&
1983                !buffer_dirty(path[level].bp_bh)) {
1984
1985                 WARN_ON(buffer_nilfs_volatile(path[level].bp_bh));
1986                 ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
1987                 if (ret < 0)
1988                         goto out;
1989         }
1990
1991         /* success */
1992         *maxlevelp = level - 1;
1993         return 0;
1994
1995         /* error */
1996  out:
1997         while (--level > minlevel)
1998                 nilfs_btree_abort_update_v(btree, path, level, dat);
1999         if (!buffer_nilfs_volatile(path[level].bp_bh))
2000                 nilfs_btree_abort_update_v(btree, path, level, dat);
2001         return ret;
2002 }
2003
2004 static void nilfs_btree_commit_propagate_v(struct nilfs_bmap *btree,
2005                                            struct nilfs_btree_path *path,
2006                                            int minlevel, int maxlevel,
2007                                            struct buffer_head *bh,
2008                                            struct inode *dat)
2009 {
2010         int level;
2011
2012         if (!buffer_nilfs_volatile(path[minlevel].bp_bh))
2013                 nilfs_btree_commit_update_v(btree, path, minlevel, dat);
2014
2015         for (level = minlevel + 1; level <= maxlevel; level++)
2016                 nilfs_btree_commit_update_v(btree, path, level, dat);
2017 }
2018
2019 static int nilfs_btree_propagate_v(struct nilfs_bmap *btree,
2020                                    struct nilfs_btree_path *path,
2021                                    int level, struct buffer_head *bh)
2022 {
2023         int maxlevel = 0, ret;
2024         struct nilfs_btree_node *parent;
2025         struct inode *dat = nilfs_bmap_get_dat(btree);
2026         __u64 ptr;
2027         int ncmax;
2028
2029         get_bh(bh);
2030         path[level].bp_bh = bh;
2031         ret = nilfs_btree_prepare_propagate_v(btree, path, level, &maxlevel,
2032                                               dat);
2033         if (ret < 0)
2034                 goto out;
2035
2036         if (buffer_nilfs_volatile(path[level].bp_bh)) {
2037                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2038                 ptr = nilfs_btree_node_get_ptr(parent,
2039                                                path[level + 1].bp_index,
2040                                                ncmax);
2041                 ret = nilfs_dat_mark_dirty(dat, ptr);
2042                 if (ret < 0)
2043                         goto out;
2044         }
2045
2046         nilfs_btree_commit_propagate_v(btree, path, level, maxlevel, bh, dat);
2047
2048  out:
2049         brelse(path[level].bp_bh);
2050         path[level].bp_bh = NULL;
2051         return ret;
2052 }
2053
2054 static int nilfs_btree_propagate(struct nilfs_bmap *btree,
2055                                  struct buffer_head *bh)
2056 {
2057         struct nilfs_btree_path *path;
2058         struct nilfs_btree_node *node;
2059         __u64 key;
2060         int level, ret;
2061
2062         WARN_ON(!buffer_dirty(bh));
2063
2064         path = nilfs_btree_alloc_path();
2065         if (path == NULL)
2066                 return -ENOMEM;
2067
2068         if (buffer_nilfs_node(bh)) {
2069                 node = (struct nilfs_btree_node *)bh->b_data;
2070                 key = nilfs_btree_node_get_key(node, 0);
2071                 level = nilfs_btree_node_get_level(node);
2072         } else {
2073                 key = nilfs_bmap_data_get_key(btree, bh);
2074                 level = NILFS_BTREE_LEVEL_DATA;
2075         }
2076
2077         ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
2078         if (ret < 0) {
2079                 if (unlikely(ret == -ENOENT))
2080                         nilfs_crit(btree->b_inode->i_sb,
2081                                    "writing node/leaf block does not appear in b-tree (ino=%lu) at key=%llu, level=%d",
2082                                    btree->b_inode->i_ino,
2083                                    (unsigned long long)key, level);
2084                 goto out;
2085         }
2086
2087         ret = NILFS_BMAP_USE_VBN(btree) ?
2088                 nilfs_btree_propagate_v(btree, path, level, bh) :
2089                 nilfs_btree_propagate_p(btree, path, level, bh);
2090
2091  out:
2092         nilfs_btree_free_path(path);
2093
2094         return ret;
2095 }
2096
2097 static int nilfs_btree_propagate_gc(struct nilfs_bmap *btree,
2098                                     struct buffer_head *bh)
2099 {
2100         return nilfs_dat_mark_dirty(nilfs_bmap_get_dat(btree), bh->b_blocknr);
2101 }
2102
2103 static void nilfs_btree_add_dirty_buffer(struct nilfs_bmap *btree,
2104                                          struct list_head *lists,
2105                                          struct buffer_head *bh)
2106 {
2107         struct list_head *head;
2108         struct buffer_head *cbh;
2109         struct nilfs_btree_node *node, *cnode;
2110         __u64 key, ckey;
2111         int level;
2112
2113         get_bh(bh);
2114         node = (struct nilfs_btree_node *)bh->b_data;
2115         key = nilfs_btree_node_get_key(node, 0);
2116         level = nilfs_btree_node_get_level(node);
2117         if (level < NILFS_BTREE_LEVEL_NODE_MIN ||
2118             level >= NILFS_BTREE_LEVEL_MAX) {
2119                 dump_stack();
2120                 nilfs_warn(btree->b_inode->i_sb,
2121                            "invalid btree level: %d (key=%llu, ino=%lu, blocknr=%llu)",
2122                            level, (unsigned long long)key,
2123                            btree->b_inode->i_ino,
2124                            (unsigned long long)bh->b_blocknr);
2125                 return;
2126         }
2127
2128         list_for_each(head, &lists[level]) {
2129                 cbh = list_entry(head, struct buffer_head, b_assoc_buffers);
2130                 cnode = (struct nilfs_btree_node *)cbh->b_data;
2131                 ckey = nilfs_btree_node_get_key(cnode, 0);
2132                 if (key < ckey)
2133                         break;
2134         }
2135         list_add_tail(&bh->b_assoc_buffers, head);
2136 }
2137
2138 static void nilfs_btree_lookup_dirty_buffers(struct nilfs_bmap *btree,
2139                                              struct list_head *listp)
2140 {
2141         struct inode *btnc_inode = NILFS_BMAP_I(btree)->i_assoc_inode;
2142         struct address_space *btcache = btnc_inode->i_mapping;
2143         struct list_head lists[NILFS_BTREE_LEVEL_MAX];
2144         struct pagevec pvec;
2145         struct buffer_head *bh, *head;
2146         pgoff_t index = 0;
2147         int level, i;
2148
2149         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
2150              level < NILFS_BTREE_LEVEL_MAX;
2151              level++)
2152                 INIT_LIST_HEAD(&lists[level]);
2153
2154         pagevec_init(&pvec);
2155
2156         while (pagevec_lookup_tag(&pvec, btcache, &index,
2157                                         PAGECACHE_TAG_DIRTY)) {
2158                 for (i = 0; i < pagevec_count(&pvec); i++) {
2159                         bh = head = page_buffers(pvec.pages[i]);
2160                         do {
2161                                 if (buffer_dirty(bh))
2162                                         nilfs_btree_add_dirty_buffer(btree,
2163                                                                      lists, bh);
2164                         } while ((bh = bh->b_this_page) != head);
2165                 }
2166                 pagevec_release(&pvec);
2167                 cond_resched();
2168         }
2169
2170         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
2171              level < NILFS_BTREE_LEVEL_MAX;
2172              level++)
2173                 list_splice_tail(&lists[level], listp);
2174 }
2175
2176 static int nilfs_btree_assign_p(struct nilfs_bmap *btree,
2177                                 struct nilfs_btree_path *path,
2178                                 int level,
2179                                 struct buffer_head **bh,
2180                                 sector_t blocknr,
2181                                 union nilfs_binfo *binfo)
2182 {
2183         struct nilfs_btree_node *parent;
2184         __u64 key;
2185         __u64 ptr;
2186         int ncmax, ret;
2187
2188         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2189         ptr = nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
2190                                        ncmax);
2191         if (buffer_nilfs_node(*bh)) {
2192                 path[level].bp_ctxt.oldkey = ptr;
2193                 path[level].bp_ctxt.newkey = blocknr;
2194                 path[level].bp_ctxt.bh = *bh;
2195                 ret = nilfs_btnode_prepare_change_key(
2196                         NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
2197                         &path[level].bp_ctxt);
2198                 if (ret < 0)
2199                         return ret;
2200                 nilfs_btnode_commit_change_key(
2201                         NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
2202                         &path[level].bp_ctxt);
2203                 *bh = path[level].bp_ctxt.bh;
2204         }
2205
2206         nilfs_btree_node_set_ptr(parent, path[level + 1].bp_index, blocknr,
2207                                  ncmax);
2208
2209         key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
2210         /* on-disk format */
2211         binfo->bi_dat.bi_blkoff = cpu_to_le64(key);
2212         binfo->bi_dat.bi_level = level;
2213
2214         return 0;
2215 }
2216
2217 static int nilfs_btree_assign_v(struct nilfs_bmap *btree,
2218                                 struct nilfs_btree_path *path,
2219                                 int level,
2220                                 struct buffer_head **bh,
2221                                 sector_t blocknr,
2222                                 union nilfs_binfo *binfo)
2223 {
2224         struct nilfs_btree_node *parent;
2225         struct inode *dat = nilfs_bmap_get_dat(btree);
2226         __u64 key;
2227         __u64 ptr;
2228         union nilfs_bmap_ptr_req req;
2229         int ncmax, ret;
2230
2231         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2232         ptr = nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
2233                                        ncmax);
2234         req.bpr_ptr = ptr;
2235         ret = nilfs_dat_prepare_start(dat, &req.bpr_req);
2236         if (ret < 0)
2237                 return ret;
2238         nilfs_dat_commit_start(dat, &req.bpr_req, blocknr);
2239
2240         key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
2241         /* on-disk format */
2242         binfo->bi_v.bi_vblocknr = cpu_to_le64(ptr);
2243         binfo->bi_v.bi_blkoff = cpu_to_le64(key);
2244
2245         return 0;
2246 }
2247
2248 static int nilfs_btree_assign(struct nilfs_bmap *btree,
2249                               struct buffer_head **bh,
2250                               sector_t blocknr,
2251                               union nilfs_binfo *binfo)
2252 {
2253         struct nilfs_btree_path *path;
2254         struct nilfs_btree_node *node;
2255         __u64 key;
2256         int level, ret;
2257
2258         path = nilfs_btree_alloc_path();
2259         if (path == NULL)
2260                 return -ENOMEM;
2261
2262         if (buffer_nilfs_node(*bh)) {
2263                 node = (struct nilfs_btree_node *)(*bh)->b_data;
2264                 key = nilfs_btree_node_get_key(node, 0);
2265                 level = nilfs_btree_node_get_level(node);
2266         } else {
2267                 key = nilfs_bmap_data_get_key(btree, *bh);
2268                 level = NILFS_BTREE_LEVEL_DATA;
2269         }
2270
2271         ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
2272         if (ret < 0) {
2273                 WARN_ON(ret == -ENOENT);
2274                 goto out;
2275         }
2276
2277         ret = NILFS_BMAP_USE_VBN(btree) ?
2278                 nilfs_btree_assign_v(btree, path, level, bh, blocknr, binfo) :
2279                 nilfs_btree_assign_p(btree, path, level, bh, blocknr, binfo);
2280
2281  out:
2282         nilfs_btree_free_path(path);
2283
2284         return ret;
2285 }
2286
2287 static int nilfs_btree_assign_gc(struct nilfs_bmap *btree,
2288                                  struct buffer_head **bh,
2289                                  sector_t blocknr,
2290                                  union nilfs_binfo *binfo)
2291 {
2292         struct nilfs_btree_node *node;
2293         __u64 key;
2294         int ret;
2295
2296         ret = nilfs_dat_move(nilfs_bmap_get_dat(btree), (*bh)->b_blocknr,
2297                              blocknr);
2298         if (ret < 0)
2299                 return ret;
2300
2301         if (buffer_nilfs_node(*bh)) {
2302                 node = (struct nilfs_btree_node *)(*bh)->b_data;
2303                 key = nilfs_btree_node_get_key(node, 0);
2304         } else
2305                 key = nilfs_bmap_data_get_key(btree, *bh);
2306
2307         /* on-disk format */
2308         binfo->bi_v.bi_vblocknr = cpu_to_le64((*bh)->b_blocknr);
2309         binfo->bi_v.bi_blkoff = cpu_to_le64(key);
2310
2311         return 0;
2312 }
2313
2314 static int nilfs_btree_mark(struct nilfs_bmap *btree, __u64 key, int level)
2315 {
2316         struct buffer_head *bh;
2317         struct nilfs_btree_path *path;
2318         __u64 ptr;
2319         int ret;
2320
2321         path = nilfs_btree_alloc_path();
2322         if (path == NULL)
2323                 return -ENOMEM;
2324
2325         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1, 0);
2326         if (ret < 0) {
2327                 WARN_ON(ret == -ENOENT);
2328                 goto out;
2329         }
2330         ret = nilfs_btree_get_block(btree, ptr, &bh);
2331         if (ret < 0) {
2332                 WARN_ON(ret == -ENOENT);
2333                 goto out;
2334         }
2335
2336         if (!buffer_dirty(bh))
2337                 mark_buffer_dirty(bh);
2338         brelse(bh);
2339         if (!nilfs_bmap_dirty(btree))
2340                 nilfs_bmap_set_dirty(btree);
2341
2342  out:
2343         nilfs_btree_free_path(path);
2344         return ret;
2345 }
2346
2347 static const struct nilfs_bmap_operations nilfs_btree_ops = {
2348         .bop_lookup             =       nilfs_btree_lookup,
2349         .bop_lookup_contig      =       nilfs_btree_lookup_contig,
2350         .bop_insert             =       nilfs_btree_insert,
2351         .bop_delete             =       nilfs_btree_delete,
2352         .bop_clear              =       NULL,
2353
2354         .bop_propagate          =       nilfs_btree_propagate,
2355
2356         .bop_lookup_dirty_buffers =     nilfs_btree_lookup_dirty_buffers,
2357
2358         .bop_assign             =       nilfs_btree_assign,
2359         .bop_mark               =       nilfs_btree_mark,
2360
2361         .bop_seek_key           =       nilfs_btree_seek_key,
2362         .bop_last_key           =       nilfs_btree_last_key,
2363
2364         .bop_check_insert       =       NULL,
2365         .bop_check_delete       =       nilfs_btree_check_delete,
2366         .bop_gather_data        =       nilfs_btree_gather_data,
2367 };
2368
2369 static const struct nilfs_bmap_operations nilfs_btree_ops_gc = {
2370         .bop_lookup             =       NULL,
2371         .bop_lookup_contig      =       NULL,
2372         .bop_insert             =       NULL,
2373         .bop_delete             =       NULL,
2374         .bop_clear              =       NULL,
2375
2376         .bop_propagate          =       nilfs_btree_propagate_gc,
2377
2378         .bop_lookup_dirty_buffers =     nilfs_btree_lookup_dirty_buffers,
2379
2380         .bop_assign             =       nilfs_btree_assign_gc,
2381         .bop_mark               =       NULL,
2382
2383         .bop_seek_key           =       NULL,
2384         .bop_last_key           =       NULL,
2385
2386         .bop_check_insert       =       NULL,
2387         .bop_check_delete       =       NULL,
2388         .bop_gather_data        =       NULL,
2389 };
2390
2391 static void __nilfs_btree_init(struct nilfs_bmap *bmap)
2392 {
2393         bmap->b_ops = &nilfs_btree_ops;
2394         bmap->b_nchildren_per_block =
2395                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
2396 }
2397
2398 int nilfs_btree_init(struct nilfs_bmap *bmap)
2399 {
2400         int ret = 0;
2401
2402         __nilfs_btree_init(bmap);
2403
2404         if (nilfs_btree_root_broken(nilfs_btree_get_root(bmap), bmap->b_inode))
2405                 ret = -EIO;
2406         else
2407                 ret = nilfs_attach_btree_node_cache(
2408                         &NILFS_BMAP_I(bmap)->vfs_inode);
2409
2410         return ret;
2411 }
2412
2413 void nilfs_btree_init_gc(struct nilfs_bmap *bmap)
2414 {
2415         bmap->b_ops = &nilfs_btree_ops_gc;
2416         bmap->b_nchildren_per_block =
2417                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
2418 }