fs/nilfs2/btree.c

   1 /*
   2  * btree.c - NILFS B-tree.
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * Written by Koji Sato.
  17  */
  18
  19 #include <linux/slab.h>
  20 #include <linux/string.h>
  21 #include <linux/errno.h>
  22 #include <linux/pagevec.h>
  23 #include "nilfs.h"
  24 #include "page.h"
  25 #include "btnode.h"
  26 #include "btree.h"
  27 #include "alloc.h"
  28 #include "dat.h"
  29
  30 static void __nilfs_btree_init(struct nilfs_bmap *bmap);
  31
  32 static struct nilfs_btree_path *nilfs_btree_alloc_path(void)
  33 {
  34         struct nilfs_btree_path *path;
  35         int level = NILFS_BTREE_LEVEL_DATA;
  36
  37         path = kmem_cache_alloc(nilfs_btree_path_cache, GFP_NOFS);
  38         if (path == NULL)
  39                 goto out;
  40
  41         for (; level < NILFS_BTREE_LEVEL_MAX; level++) {
  42                 path[level].bp_bh = NULL;
  43                 path[level].bp_sib_bh = NULL;
  44                 path[level].bp_index = 0;
  45                 path[level].bp_oldreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
  46                 path[level].bp_newreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
  47                 path[level].bp_op = NULL;
  48         }
  49
  50 out:
  51         return path;
  52 }
  53
  54 static void nilfs_btree_free_path(struct nilfs_btree_path *path)
  55 {
  56         int level = NILFS_BTREE_LEVEL_DATA;
  57
  58         for (; level < NILFS_BTREE_LEVEL_MAX; level++)
  59                 brelse(path[level].bp_bh);
  60
  61         kmem_cache_free(nilfs_btree_path_cache, path);
  62 }
  63
  64 /*
  65  * B-tree node operations
  66  */
  67 static int nilfs_btree_get_new_block(const struct nilfs_bmap *btree,
  68                                      __u64 ptr, struct buffer_head **bhp)
  69 {
  70         struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;
  71         struct buffer_head *bh;
  72
  73         bh = nilfs_btnode_create_block(btnc, ptr);
  74         if (!bh)
  75                 return -ENOMEM;
  76
  77         set_buffer_nilfs_volatile(bh);
  78         *bhp = bh;
  79         return 0;
  80 }
  81
  82 static int nilfs_btree_node_get_flags(const struct nilfs_btree_node *node)
  83 {
  84         return node->bn_flags;
  85 }
  86
  87 static void
  88 nilfs_btree_node_set_flags(struct nilfs_btree_node *node, int flags)
  89 {
  90         node->bn_flags = flags;
  91 }
  92
  93 static int nilfs_btree_node_root(const struct nilfs_btree_node *node)
  94 {
  95         return nilfs_btree_node_get_flags(node) & NILFS_BTREE_NODE_ROOT;
  96 }
  97
  98 static int nilfs_btree_node_get_level(const struct nilfs_btree_node *node)
  99 {
 100         return node->bn_level;
 101 }
 102
 103 static void
 104 nilfs_btree_node_set_level(struct nilfs_btree_node *node, int level)
 105 {
 106         node->bn_level = level;
 107 }
 108
 109 static int nilfs_btree_node_get_nchildren(const struct nilfs_btree_node *node)
 110 {
 111         return le16_to_cpu(node->bn_nchildren);
 112 }
 113
 114 static void
 115 nilfs_btree_node_set_nchildren(struct nilfs_btree_node *node, int nchildren)
 116 {
 117         node->bn_nchildren = cpu_to_le16(nchildren);
 118 }
 119
 120 static int nilfs_btree_node_size(const struct nilfs_bmap *btree)
 121 {
 122         return i_blocksize(btree->b_inode);
 123 }
 124
 125 static int nilfs_btree_nchildren_per_block(const struct nilfs_bmap *btree)
 126 {
 127         return btree->b_nchildren_per_block;
 128 }
 129
 130 static __le64 *
 131 nilfs_btree_node_dkeys(const struct nilfs_btree_node *node)
 132 {
 133         return (__le64 *)((char *)(node + 1) +
 134                           (nilfs_btree_node_root(node) ?
 135                            0 : NILFS_BTREE_NODE_EXTRA_PAD_SIZE));
 136 }
 137
 138 static __le64 *
 139 nilfs_btree_node_dptrs(const struct nilfs_btree_node *node, int ncmax)
 140 {
 141         return (__le64 *)(nilfs_btree_node_dkeys(node) + ncmax);
 142 }
 143
 144 static __u64
 145 nilfs_btree_node_get_key(const struct nilfs_btree_node *node, int index)
 146 {
 147         return le64_to_cpu(*(nilfs_btree_node_dkeys(node) + index));
 148 }
 149
 150 static void
 151 nilfs_btree_node_set_key(struct nilfs_btree_node *node, int index, __u64 key)
 152 {
 153         *(nilfs_btree_node_dkeys(node) + index) = cpu_to_le64(key);
 154 }
 155
 156 static __u64
 157 nilfs_btree_node_get_ptr(const struct nilfs_btree_node *node, int index,
 158                          int ncmax)
 159 {
 160         return le64_to_cpu(*(nilfs_btree_node_dptrs(node, ncmax) + index));
 161 }
 162
 163 static void
 164 nilfs_btree_node_set_ptr(struct nilfs_btree_node *node, int index, __u64 ptr,
 165                          int ncmax)
 166 {
 167         *(nilfs_btree_node_dptrs(node, ncmax) + index) = cpu_to_le64(ptr);
 168 }
 169
 170 static void nilfs_btree_node_init(struct nilfs_btree_node *node, int flags,
 171                                   int level, int nchildren, int ncmax,
 172                                   const __u64 *keys, const __u64 *ptrs)
 173 {
 174         __le64 *dkeys;
 175         __le64 *dptrs;
 176         int i;
 177
 178         nilfs_btree_node_set_flags(node, flags);
 179         nilfs_btree_node_set_level(node, level);
 180         nilfs_btree_node_set_nchildren(node, nchildren);
 181
 182         dkeys = nilfs_btree_node_dkeys(node);
 183         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 184         for (i = 0; i < nchildren; i++) {
 185                 dkeys[i] = cpu_to_le64(keys[i]);
 186                 dptrs[i] = cpu_to_le64(ptrs[i]);
 187         }
 188 }
 189
 190 /* Assume the buffer heads corresponding to left and right are locked. */
 191 static void nilfs_btree_node_move_left(struct nilfs_btree_node *left,
 192                                        struct nilfs_btree_node *right,
 193                                        int n, int lncmax, int rncmax)
 194 {
 195         __le64 *ldkeys, *rdkeys;
 196         __le64 *ldptrs, *rdptrs;
 197         int lnchildren, rnchildren;
 198
 199         ldkeys = nilfs_btree_node_dkeys(left);
 200         ldptrs = nilfs_btree_node_dptrs(left, lncmax);
 201         lnchildren = nilfs_btree_node_get_nchildren(left);
 202
 203         rdkeys = nilfs_btree_node_dkeys(right);
 204         rdptrs = nilfs_btree_node_dptrs(right, rncmax);
 205         rnchildren = nilfs_btree_node_get_nchildren(right);
 206
 207         memcpy(ldkeys + lnchildren, rdkeys, n * sizeof(*rdkeys));
 208         memcpy(ldptrs + lnchildren, rdptrs, n * sizeof(*rdptrs));
 209         memmove(rdkeys, rdkeys + n, (rnchildren - n) * sizeof(*rdkeys));
 210         memmove(rdptrs, rdptrs + n, (rnchildren - n) * sizeof(*rdptrs));
 211
 212         lnchildren += n;
 213         rnchildren -= n;
 214         nilfs_btree_node_set_nchildren(left, lnchildren);
 215         nilfs_btree_node_set_nchildren(right, rnchildren);
 216 }
 217
 218 /* Assume that the buffer heads corresponding to left and right are locked. */
 219 static void nilfs_btree_node_move_right(struct nilfs_btree_node *left,
 220                                         struct nilfs_btree_node *right,
 221                                         int n, int lncmax, int rncmax)
 222 {
 223         __le64 *ldkeys, *rdkeys;
 224         __le64 *ldptrs, *rdptrs;
 225         int lnchildren, rnchildren;
 226
 227         ldkeys = nilfs_btree_node_dkeys(left);
 228         ldptrs = nilfs_btree_node_dptrs(left, lncmax);
 229         lnchildren = nilfs_btree_node_get_nchildren(left);
 230
 231         rdkeys = nilfs_btree_node_dkeys(right);
 232         rdptrs = nilfs_btree_node_dptrs(right, rncmax);
 233         rnchildren = nilfs_btree_node_get_nchildren(right);
 234
 235         memmove(rdkeys + n, rdkeys, rnchildren * sizeof(*rdkeys));
 236         memmove(rdptrs + n, rdptrs, rnchildren * sizeof(*rdptrs));
 237         memcpy(rdkeys, ldkeys + lnchildren - n, n * sizeof(*rdkeys));
 238         memcpy(rdptrs, ldptrs + lnchildren - n, n * sizeof(*rdptrs));
 239
 240         lnchildren -= n;
 241         rnchildren += n;
 242         nilfs_btree_node_set_nchildren(left, lnchildren);
 243         nilfs_btree_node_set_nchildren(right, rnchildren);
 244 }
 245
 246 /* Assume that the buffer head corresponding to node is locked. */
 247 static void nilfs_btree_node_insert(struct nilfs_btree_node *node, int index,
 248                                     __u64 key, __u64 ptr, int ncmax)
 249 {
 250         __le64 *dkeys;
 251         __le64 *dptrs;
 252         int nchildren;
 253
 254         dkeys = nilfs_btree_node_dkeys(node);
 255         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 256         nchildren = nilfs_btree_node_get_nchildren(node);
 257         if (index < nchildren) {
 258                 memmove(dkeys + index + 1, dkeys + index,
 259                         (nchildren - index) * sizeof(*dkeys));
 260                 memmove(dptrs + index + 1, dptrs + index,
 261                         (nchildren - index) * sizeof(*dptrs));
 262         }
 263         dkeys[index] = cpu_to_le64(key);
 264         dptrs[index] = cpu_to_le64(ptr);
 265         nchildren++;
 266         nilfs_btree_node_set_nchildren(node, nchildren);
 267 }
 268
 269 /* Assume that the buffer head corresponding to node is locked. */
 270 static void nilfs_btree_node_delete(struct nilfs_btree_node *node, int index,
 271                                     __u64 *keyp, __u64 *ptrp, int ncmax)
 272 {
 273         __u64 key;
 274         __u64 ptr;
 275         __le64 *dkeys;
 276         __le64 *dptrs;
 277         int nchildren;
 278
 279         dkeys = nilfs_btree_node_dkeys(node);
 280         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 281         key = le64_to_cpu(dkeys[index]);
 282         ptr = le64_to_cpu(dptrs[index]);
 283         nchildren = nilfs_btree_node_get_nchildren(node);
 284         if (keyp != NULL)
 285                 *keyp = key;
 286         if (ptrp != NULL)
 287                 *ptrp = ptr;
 288
 289         if (index < nchildren - 1) {
 290                 memmove(dkeys + index, dkeys + index + 1,
 291                         (nchildren - index - 1) * sizeof(*dkeys));
 292                 memmove(dptrs + index, dptrs + index + 1,
 293                         (nchildren - index - 1) * sizeof(*dptrs));
 294         }
 295         nchildren--;
 296         nilfs_btree_node_set_nchildren(node, nchildren);
 297 }
 298
 299 static int nilfs_btree_node_lookup(const struct nilfs_btree_node *node,
 300                                    __u64 key, int *indexp)
 301 {
 302         __u64 nkey;
 303         int index, low, high, s;
 304
 305         /* binary search */
 306         low = 0;
 307         high = nilfs_btree_node_get_nchildren(node) - 1;
 308         index = 0;
 309         s = 0;
 310         while (low <= high) {
 311                 index = (low + high) / 2;
 312                 nkey = nilfs_btree_node_get_key(node, index);
 313                 if (nkey == key) {
 314                         s = 0;
 315                         goto out;
 316                 } else if (nkey < key) {
 317                         low = index + 1;
 318                         s = -1;
 319                 } else {
 320                         high = index - 1;
 321                         s = 1;
 322                 }
 323         }
 324
 325         /* adjust index */
 326         if (nilfs_btree_node_get_level(node) > NILFS_BTREE_LEVEL_NODE_MIN) {
 327                 if (s > 0 && index > 0)
 328                         index--;
 329         } else if (s < 0)
 330                 index++;
 331
 332  out:
 333         *indexp = index;
 334
 335         return s == 0;
 336 }
 337
 338 /**
 339  * nilfs_btree_node_broken - verify consistency of btree node
 340  * @node: btree node block to be examined
 341  * @size: node size (in bytes)
 342  * @inode: host inode of btree
 343  * @blocknr: block number
 344  *
 345  * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
 346  */
 347 static int nilfs_btree_node_broken(const struct nilfs_btree_node *node,
 348                                    size_t size, struct inode *inode,
 349                                    sector_t blocknr)
 350 {
 351         int level, flags, nchildren;
 352         int ret = 0;
 353
 354         level = nilfs_btree_node_get_level(node);
 355         flags = nilfs_btree_node_get_flags(node);
 356         nchildren = nilfs_btree_node_get_nchildren(node);
 357
 358         if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
 359                      level >= NILFS_BTREE_LEVEL_MAX ||
 360                      (flags & NILFS_BTREE_NODE_ROOT) ||
 361                      nchildren < 0 ||
 362                      nchildren > NILFS_BTREE_NODE_NCHILDREN_MAX(size))) {
 363                 nilfs_msg(inode->i_sb, KERN_CRIT,
 364                           "bad btree node (ino=%lu, blocknr=%llu): level = %d, flags = 0x%x, nchildren = %d",
 365                           inode->i_ino, (unsigned long long)blocknr, level,
 366                           flags, nchildren);
 367                 ret = 1;
 368         }
 369         return ret;
 370 }
 371
 372 /**
 373  * nilfs_btree_root_broken - verify consistency of btree root node
 374  * @node: btree root node to be examined
 375  * @inode: host inode of btree
 376  *
 377  * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
 378  */
 379 static int nilfs_btree_root_broken(const struct nilfs_btree_node *node,
 380                                    struct inode *inode)
 381 {
 382         int level, flags, nchildren;
 383         int ret = 0;
 384
 385         level = nilfs_btree_node_get_level(node);
 386         flags = nilfs_btree_node_get_flags(node);
 387         nchildren = nilfs_btree_node_get_nchildren(node);
 388
 389         if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
 390                      level >= NILFS_BTREE_LEVEL_MAX ||
 391                      nchildren < 0 ||
 392                      nchildren > NILFS_BTREE_ROOT_NCHILDREN_MAX)) {
 393                 nilfs_msg(inode->i_sb, KERN_CRIT,
 394                           "bad btree root (ino=%lu): level = %d, flags = 0x%x, nchildren = %d",
 395                           inode->i_ino, level, flags, nchildren);
 396                 ret = 1;
 397         }
 398         return ret;
 399 }
 400
 401 int nilfs_btree_broken_node_block(struct buffer_head *bh)
 402 {
 403         struct inode *inode;
 404         int ret;
 405
 406         if (buffer_nilfs_checked(bh))
 407                 return 0;
 408
 409         inode = bh->b_page->mapping->host;
 410         ret = nilfs_btree_node_broken((struct nilfs_btree_node *)bh->b_data,
 411                                       bh->b_size, inode, bh->b_blocknr);
 412         if (likely(!ret))
 413                 set_buffer_nilfs_checked(bh);
 414         return ret;
 415 }
 416
 417 static struct nilfs_btree_node *
 418 nilfs_btree_get_root(const struct nilfs_bmap *btree)
 419 {
 420         return (struct nilfs_btree_node *)btree->b_u.u_data;
 421 }
 422
 423 static struct nilfs_btree_node *
 424 nilfs_btree_get_nonroot_node(const struct nilfs_btree_path *path, int level)
 425 {
 426         return (struct nilfs_btree_node *)path[level].bp_bh->b_data;
 427 }
 428
 429 static struct nilfs_btree_node *
 430 nilfs_btree_get_sib_node(const struct nilfs_btree_path *path, int level)
 431 {
 432         return (struct nilfs_btree_node *)path[level].bp_sib_bh->b_data;
 433 }
 434
 435 static int nilfs_btree_height(const struct nilfs_bmap *btree)
 436 {
 437         return nilfs_btree_node_get_level(nilfs_btree_get_root(btree)) + 1;
 438 }
 439
 440 static struct nilfs_btree_node *
 441 nilfs_btree_get_node(const struct nilfs_bmap *btree,
 442                      const struct nilfs_btree_path *path,
 443                      int level, int *ncmaxp)
 444 {
 445         struct nilfs_btree_node *node;
 446
 447         if (level == nilfs_btree_height(btree) - 1) {
 448                 node = nilfs_btree_get_root(btree);
 449                 *ncmaxp = NILFS_BTREE_ROOT_NCHILDREN_MAX;
 450         } else {
 451                 node = nilfs_btree_get_nonroot_node(path, level);
 452                 *ncmaxp = nilfs_btree_nchildren_per_block(btree);
 453         }
 454         return node;
 455 }
 456
 457 static int nilfs_btree_bad_node(const struct nilfs_bmap *btree,
 458                                 struct nilfs_btree_node *node, int level)
 459 {
 460         if (unlikely(nilfs_btree_node_get_level(node) != level)) {
 461                 dump_stack();
 462                 nilfs_msg(btree->b_inode->i_sb, KERN_CRIT,
 463                           "btree level mismatch (ino=%lu): %d != %d",
 464                           btree->b_inode->i_ino,
 465                           nilfs_btree_node_get_level(node), level);
 466                 return 1;
 467         }
 468         return 0;
 469 }
 470
 471 struct nilfs_btree_readahead_info {
 472         struct nilfs_btree_node *node;  /* parent node */
 473         int max_ra_blocks;              /* max nof blocks to read ahead */
 474         int index;                      /* current index on the parent node */
 475         int ncmax;                      /* nof children in the parent node */
 476 };
 477
 478 static int __nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
 479                                    struct buffer_head **bhp,
 480                                    const struct nilfs_btree_readahead_info *ra)
 481 {
 482         struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;
 483         struct buffer_head *bh, *ra_bh;
 484         sector_t submit_ptr = 0;
 485         int ret;
 486
 487         ret = nilfs_btnode_submit_block(btnc, ptr, 0, REQ_OP_READ, 0, &bh,
 488                                         &submit_ptr);
 489         if (ret) {
 490                 if (ret != -EEXIST)
 491                         return ret;
 492                 goto out_check;
 493         }
 494
 495         if (ra) {
 496                 int i, n;
 497                 __u64 ptr2;
 498
 499                 /* read ahead sibling nodes */
 500                 for (n = ra->max_ra_blocks, i = ra->index + 1;
 501                      n > 0 && i < ra->ncmax; n--, i++) {
 502                         ptr2 = nilfs_btree_node_get_ptr(ra->node, i, ra->ncmax);
 503
 504                         ret = nilfs_btnode_submit_block(btnc, ptr2, 0,
 505                                                         REQ_OP_READ, REQ_RAHEAD,
 506                                                         &ra_bh, &submit_ptr);
 507                         if (likely(!ret || ret == -EEXIST))
 508                                 brelse(ra_bh);
 509                         else if (ret != -EBUSY)
 510                                 break;
 511                         if (!buffer_locked(bh))
 512                                 goto out_no_wait;
 513                 }
 514         }
 515
 516         wait_on_buffer(bh);
 517
 518  out_no_wait:
 519         if (!buffer_uptodate(bh)) {
 520                 nilfs_msg(btree->b_inode->i_sb, KERN_ERR,
 521                           "I/O error reading b-tree node block (ino=%lu, blocknr=%llu)",
 522                           btree->b_inode->i_ino, (unsigned long long)ptr);
 523                 brelse(bh);
 524                 return -EIO;
 525         }
 526
 527  out_check:
 528         if (nilfs_btree_broken_node_block(bh)) {
 529                 clear_buffer_uptodate(bh);
 530                 brelse(bh);
 531                 return -EINVAL;
 532         }
 533
 534         *bhp = bh;
 535         return 0;
 536 }
 537
 538 static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
 539                                    struct buffer_head **bhp)
 540 {
 541         return __nilfs_btree_get_block(btree, ptr, bhp, NULL);
 542 }
 543
 544 static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree,
 545                                  struct nilfs_btree_path *path,
 546                                  __u64 key, __u64 *ptrp, int minlevel,
 547                                  int readahead)
 548 {
 549         struct nilfs_btree_node *node;
 550         struct nilfs_btree_readahead_info p, *ra;
 551         __u64 ptr;
 552         int level, index, found, ncmax, ret;
 553
 554         node = nilfs_btree_get_root(btree);
 555         level = nilfs_btree_node_get_level(node);
 556         if (level < minlevel || nilfs_btree_node_get_nchildren(node) <= 0)
 557                 return -ENOENT;
 558
 559         found = nilfs_btree_node_lookup(node, key, &index);
 560         ptr = nilfs_btree_node_get_ptr(node, index,
 561                                        NILFS_BTREE_ROOT_NCHILDREN_MAX);
 562         path[level].bp_bh = NULL;
 563         path[level].bp_index = index;
 564
 565         ncmax = nilfs_btree_nchildren_per_block(btree);
 566
 567         while (--level >= minlevel) {
 568                 ra = NULL;
 569                 if (level == NILFS_BTREE_LEVEL_NODE_MIN && readahead) {
 570                         p.node = nilfs_btree_get_node(btree, path, level + 1,
 571                                                       &p.ncmax);
 572                         p.index = index;
 573                         p.max_ra_blocks = 7;
 574                         ra = &p;
 575                 }
 576                 ret = __nilfs_btree_get_block(btree, ptr, &path[level].bp_bh,
 577                                               ra);
 578                 if (ret < 0)
 579                         return ret;
 580
 581                 node = nilfs_btree_get_nonroot_node(path, level);
 582                 if (nilfs_btree_bad_node(btree, node, level))
 583                         return -EINVAL;
 584                 if (!found)
 585                         found = nilfs_btree_node_lookup(node, key, &index);
 586                 else
 587                         index = 0;
 588                 if (index < ncmax) {
 589                         ptr = nilfs_btree_node_get_ptr(node, index, ncmax);
 590                 } else {
 591                         WARN_ON(found || level != NILFS_BTREE_LEVEL_NODE_MIN);
 592                         /* insert */
 593                         ptr = NILFS_BMAP_INVALID_PTR;
 594                 }
 595                 path[level].bp_index = index;
 596         }
 597         if (!found)
 598                 return -ENOENT;
 599
 600         if (ptrp != NULL)
 601                 *ptrp = ptr;
 602
 603         return 0;
 604 }
 605
 606 static int nilfs_btree_do_lookup_last(const struct nilfs_bmap *btree,
 607                                       struct nilfs_btree_path *path,
 608                                       __u64 *keyp, __u64 *ptrp)
 609 {
 610         struct nilfs_btree_node *node;
 611         __u64 ptr;
 612         int index, level, ncmax, ret;
 613
 614         node = nilfs_btree_get_root(btree);
 615         index = nilfs_btree_node_get_nchildren(node) - 1;
 616         if (index < 0)
 617                 return -ENOENT;
 618         level = nilfs_btree_node_get_level(node);
 619         ptr = nilfs_btree_node_get_ptr(node, index,
 620                                        NILFS_BTREE_ROOT_NCHILDREN_MAX);
 621         path[level].bp_bh = NULL;
 622         path[level].bp_index = index;
 623         ncmax = nilfs_btree_nchildren_per_block(btree);
 624
 625         for (level--; level > 0; level--) {
 626                 ret = nilfs_btree_get_block(btree, ptr, &path[level].bp_bh);
 627                 if (ret < 0)
 628                         return ret;
 629                 node = nilfs_btree_get_nonroot_node(path, level);
 630                 if (nilfs_btree_bad_node(btree, node, level))
 631                         return -EINVAL;
 632                 index = nilfs_btree_node_get_nchildren(node) - 1;
 633                 ptr = nilfs_btree_node_get_ptr(node, index, ncmax);
 634                 path[level].bp_index = index;
 635         }
 636
 637         if (keyp != NULL)
 638                 *keyp = nilfs_btree_node_get_key(node, index);
 639         if (ptrp != NULL)
 640                 *ptrp = ptr;
 641
 642         return 0;
 643 }
 644
 645 /**
 646  * nilfs_btree_get_next_key - get next valid key from btree path array
 647  * @btree: bmap struct of btree
 648  * @path: array of nilfs_btree_path struct
 649  * @minlevel: start level
 650  * @nextkey: place to store the next valid key
 651  *
 652  * Return Value: If a next key was found, 0 is returned. Otherwise,
 653  * -ENOENT is returned.
 654  */
 655 static int nilfs_btree_get_next_key(const struct nilfs_bmap *btree,
 656                                     const struct nilfs_btree_path *path,
 657                                     int minlevel, __u64 *nextkey)
 658 {
 659         struct nilfs_btree_node *node;
 660         int maxlevel = nilfs_btree_height(btree) - 1;
 661         int index, next_adj, level;
 662
 663         /* Next index is already set to bp_index for leaf nodes. */
 664         next_adj = 0;
 665         for (level = minlevel; level <= maxlevel; level++) {
 666                 if (level == maxlevel)
 667                         node = nilfs_btree_get_root(btree);
 668                 else
 669                         node = nilfs_btree_get_nonroot_node(path, level);
 670
 671                 index = path[level].bp_index + next_adj;
 672                 if (index < nilfs_btree_node_get_nchildren(node)) {
 673                         /* Next key is in this node */
 674                         *nextkey = nilfs_btree_node_get_key(node, index);
 675                         return 0;
 676                 }
 677                 /* For non-leaf nodes, next index is stored at bp_index + 1. */
 678                 next_adj = 1;
 679         }
 680         return -ENOENT;
 681 }
 682
 683 static int nilfs_btree_lookup(const struct nilfs_bmap *btree,
 684                               __u64 key, int level, __u64 *ptrp)
 685 {
 686         struct nilfs_btree_path *path;
 687         int ret;
 688
 689         path = nilfs_btree_alloc_path();
 690         if (path == NULL)
 691                 return -ENOMEM;
 692
 693         ret = nilfs_btree_do_lookup(btree, path, key, ptrp, level, 0);
 694
 695         nilfs_btree_free_path(path);
 696
 697         return ret;
 698 }
 699
 700 static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree,
 701                                      __u64 key, __u64 *ptrp,
 702                                      unsigned int maxblocks)
 703 {
 704         struct nilfs_btree_path *path;
 705         struct nilfs_btree_node *node;
 706         struct inode *dat = NULL;
 707         __u64 ptr, ptr2;
 708         sector_t blocknr;
 709         int level = NILFS_BTREE_LEVEL_NODE_MIN;
 710         int ret, cnt, index, maxlevel, ncmax;
 711         struct nilfs_btree_readahead_info p;
 712
 713         path = nilfs_btree_alloc_path();
 714         if (path == NULL)
 715                 return -ENOMEM;
 716
 717         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level, 1);
 718         if (ret < 0)
 719                 goto out;
 720
 721         if (NILFS_BMAP_USE_VBN(btree)) {
 722                 dat = nilfs_bmap_get_dat(btree);
 723                 ret = nilfs_dat_translate(dat, ptr, &blocknr);
 724                 if (ret < 0)
 725                         goto out;
 726                 ptr = blocknr;
 727         }
 728         cnt = 1;
 729         if (cnt == maxblocks)
 730                 goto end;
 731
 732         maxlevel = nilfs_btree_height(btree) - 1;
 733         node = nilfs_btree_get_node(btree, path, level, &ncmax);
 734         index = path[level].bp_index + 1;
 735         for (;;) {
 736                 while (index < nilfs_btree_node_get_nchildren(node)) {
 737                         if (nilfs_btree_node_get_key(node, index) !=
 738                             key + cnt)
 739                                 goto end;
 740                         ptr2 = nilfs_btree_node_get_ptr(node, index, ncmax);
 741                         if (dat) {
 742                                 ret = nilfs_dat_translate(dat, ptr2, &blocknr);
 743                                 if (ret < 0)
 744                                         goto out;
 745                                 ptr2 = blocknr;
 746                         }
 747                         if (ptr2 != ptr + cnt || ++cnt == maxblocks)
 748                                 goto end;
 749                         index++;
 750                         continue;
 751                 }
 752                 if (level == maxlevel)
 753                         break;
 754
 755                 /* look-up right sibling node */
 756                 p.node = nilfs_btree_get_node(btree, path, level + 1, &p.ncmax);
 757                 p.index = path[level + 1].bp_index + 1;
 758                 p.max_ra_blocks = 7;
 759                 if (p.index >= nilfs_btree_node_get_nchildren(p.node) ||
 760                     nilfs_btree_node_get_key(p.node, p.index) != key + cnt)
 761                         break;
 762                 ptr2 = nilfs_btree_node_get_ptr(p.node, p.index, p.ncmax);
 763                 path[level + 1].bp_index = p.index;
 764
 765                 brelse(path[level].bp_bh);
 766                 path[level].bp_bh = NULL;
 767
 768                 ret = __nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh,
 769                                               &p);
 770                 if (ret < 0)
 771                         goto out;
 772                 node = nilfs_btree_get_nonroot_node(path, level);
 773                 ncmax = nilfs_btree_nchildren_per_block(btree);
 774                 index = 0;
 775                 path[level].bp_index = index;
 776         }
 777  end:
 778         *ptrp = ptr;
 779         ret = cnt;
 780  out:
 781         nilfs_btree_free_path(path);
 782         return ret;
 783 }
 784
 785 static void nilfs_btree_promote_key(struct nilfs_bmap *btree,
 786                                     struct nilfs_btree_path *path,
 787                                     int level, __u64 key)
 788 {
 789         if (level < nilfs_btree_height(btree) - 1) {
 790                 do {
 791                         nilfs_btree_node_set_key(
 792                                 nilfs_btree_get_nonroot_node(path, level),
 793                                 path[level].bp_index, key);
 794                         if (!buffer_dirty(path[level].bp_bh))
 795                                 mark_buffer_dirty(path[level].bp_bh);
 796                 } while ((path[level].bp_index == 0) &&
 797                          (++level < nilfs_btree_height(btree) - 1));
 798         }
 799
 800         /* root */
 801         if (level == nilfs_btree_height(btree) - 1) {
 802                 nilfs_btree_node_set_key(nilfs_btree_get_root(btree),
 803                                          path[level].bp_index, key);
 804         }
 805 }
 806
 807 static void nilfs_btree_do_insert(struct nilfs_bmap *btree,
 808                                   struct nilfs_btree_path *path,
 809                                   int level, __u64 *keyp, __u64 *ptrp)
 810 {
 811         struct nilfs_btree_node *node;
 812         int ncblk;
 813
 814         if (level < nilfs_btree_height(btree) - 1) {
 815                 node = nilfs_btree_get_nonroot_node(path, level);
 816                 ncblk = nilfs_btree_nchildren_per_block(btree);
 817                 nilfs_btree_node_insert(node, path[level].bp_index,
 818                                         *keyp, *ptrp, ncblk);
 819                 if (!buffer_dirty(path[level].bp_bh))
 820                         mark_buffer_dirty(path[level].bp_bh);
 821
 822                 if (path[level].bp_index == 0)
 823                         nilfs_btree_promote_key(btree, path, level + 1,
 824                                                 nilfs_btree_node_get_key(node,
 825                                                                          0));
 826         } else {
 827                 node = nilfs_btree_get_root(btree);
 828                 nilfs_btree_node_insert(node, path[level].bp_index,
 829                                         *keyp, *ptrp,
 830                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
 831         }
 832 }
 833
 834 static void nilfs_btree_carry_left(struct nilfs_bmap *btree,
 835                                    struct nilfs_btree_path *path,
 836                                    int level, __u64 *keyp, __u64 *ptrp)
 837 {
 838         struct nilfs_btree_node *node, *left;
 839         int nchildren, lnchildren, n, move, ncblk;
 840
 841         node = nilfs_btree_get_nonroot_node(path, level);
 842         left = nilfs_btree_get_sib_node(path, level);
 843         nchildren = nilfs_btree_node_get_nchildren(node);
 844         lnchildren = nilfs_btree_node_get_nchildren(left);
 845         ncblk = nilfs_btree_nchildren_per_block(btree);
 846         move = 0;
 847
 848         n = (nchildren + lnchildren + 1) / 2 - lnchildren;
 849         if (n > path[level].bp_index) {
 850                 /* move insert point */
 851                 n--;
 852                 move = 1;
 853         }
 854
 855         nilfs_btree_node_move_left(left, node, n, ncblk, ncblk);
 856
 857         if (!buffer_dirty(path[level].bp_bh))
 858                 mark_buffer_dirty(path[level].bp_bh);
 859         if (!buffer_dirty(path[level].bp_sib_bh))
 860                 mark_buffer_dirty(path[level].bp_sib_bh);
 861
 862         nilfs_btree_promote_key(btree, path, level + 1,
 863                                 nilfs_btree_node_get_key(node, 0));
 864
 865         if (move) {
 866                 brelse(path[level].bp_bh);
 867                 path[level].bp_bh = path[level].bp_sib_bh;
 868                 path[level].bp_sib_bh = NULL;
 869                 path[level].bp_index += lnchildren;
 870                 path[level + 1].bp_index--;
 871         } else {
 872                 brelse(path[level].bp_sib_bh);
 873                 path[level].bp_sib_bh = NULL;
 874                 path[level].bp_index -= n;
 875         }
 876
 877         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 878 }
 879
 880 static void nilfs_btree_carry_right(struct nilfs_bmap *btree,
 881                                     struct nilfs_btree_path *path,
 882                                     int level, __u64 *keyp, __u64 *ptrp)
 883 {
 884         struct nilfs_btree_node *node, *right;
 885         int nchildren, rnchildren, n, move, ncblk;
 886
 887         node = nilfs_btree_get_nonroot_node(path, level);
 888         right = nilfs_btree_get_sib_node(path, level);
 889         nchildren = nilfs_btree_node_get_nchildren(node);
 890         rnchildren = nilfs_btree_node_get_nchildren(right);
 891         ncblk = nilfs_btree_nchildren_per_block(btree);
 892         move = 0;
 893
 894         n = (nchildren + rnchildren + 1) / 2 - rnchildren;
 895         if (n > nchildren - path[level].bp_index) {
 896                 /* move insert point */
 897                 n--;
 898                 move = 1;
 899         }
 900
 901         nilfs_btree_node_move_right(node, right, n, ncblk, ncblk);
 902
 903         if (!buffer_dirty(path[level].bp_bh))
 904                 mark_buffer_dirty(path[level].bp_bh);
 905         if (!buffer_dirty(path[level].bp_sib_bh))
 906                 mark_buffer_dirty(path[level].bp_sib_bh);
 907
 908         path[level + 1].bp_index++;
 909         nilfs_btree_promote_key(btree, path, level + 1,
 910                                 nilfs_btree_node_get_key(right, 0));
 911         path[level + 1].bp_index--;
 912
 913         if (move) {
 914                 brelse(path[level].bp_bh);
 915                 path[level].bp_bh = path[level].bp_sib_bh;
 916                 path[level].bp_sib_bh = NULL;
 917                 path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
 918                 path[level + 1].bp_index++;
 919         } else {
 920                 brelse(path[level].bp_sib_bh);
 921                 path[level].bp_sib_bh = NULL;
 922         }
 923
 924         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 925 }
 926
 927 static void nilfs_btree_split(struct nilfs_bmap *btree,
 928                               struct nilfs_btree_path *path,
 929                               int level, __u64 *keyp, __u64 *ptrp)
 930 {
 931         struct nilfs_btree_node *node, *right;
 932         int nchildren, n, move, ncblk;
 933
 934         node = nilfs_btree_get_nonroot_node(path, level);
 935         right = nilfs_btree_get_sib_node(path, level);
 936         nchildren = nilfs_btree_node_get_nchildren(node);
 937         ncblk = nilfs_btree_nchildren_per_block(btree);
 938         move = 0;
 939
 940         n = (nchildren + 1) / 2;
 941         if (n > nchildren - path[level].bp_index) {
 942                 n--;
 943                 move = 1;
 944         }
 945
 946         nilfs_btree_node_move_right(node, right, n, ncblk, ncblk);
 947
 948         if (!buffer_dirty(path[level].bp_bh))
 949                 mark_buffer_dirty(path[level].bp_bh);
 950         if (!buffer_dirty(path[level].bp_sib_bh))
 951                 mark_buffer_dirty(path[level].bp_sib_bh);
 952
 953         if (move) {
 954                 path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
 955                 nilfs_btree_node_insert(right, path[level].bp_index,
 956                                         *keyp, *ptrp, ncblk);
 957
 958                 *keyp = nilfs_btree_node_get_key(right, 0);
 959                 *ptrp = path[level].bp_newreq.bpr_ptr;
 960
 961                 brelse(path[level].bp_bh);
 962                 path[level].bp_bh = path[level].bp_sib_bh;
 963                 path[level].bp_sib_bh = NULL;
 964         } else {
 965                 nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 966
 967                 *keyp = nilfs_btree_node_get_key(right, 0);
 968                 *ptrp = path[level].bp_newreq.bpr_ptr;
 969
 970                 brelse(path[level].bp_sib_bh);
 971                 path[level].bp_sib_bh = NULL;
 972         }
 973
 974         path[level + 1].bp_index++;
 975 }
 976
 977 static void nilfs_btree_grow(struct nilfs_bmap *btree,
 978                              struct nilfs_btree_path *path,
 979                              int level, __u64 *keyp, __u64 *ptrp)
 980 {
 981         struct nilfs_btree_node *root, *child;
 982         int n, ncblk;
 983
 984         root = nilfs_btree_get_root(btree);
 985         child = nilfs_btree_get_sib_node(path, level);
 986         ncblk = nilfs_btree_nchildren_per_block(btree);
 987
 988         n = nilfs_btree_node_get_nchildren(root);
 989
 990         nilfs_btree_node_move_right(root, child, n,
 991                                     NILFS_BTREE_ROOT_NCHILDREN_MAX, ncblk);
 992         nilfs_btree_node_set_level(root, level + 1);
 993
 994         if (!buffer_dirty(path[level].bp_sib_bh))
 995                 mark_buffer_dirty(path[level].bp_sib_bh);
 996
 997         path[level].bp_bh = path[level].bp_sib_bh;
 998         path[level].bp_sib_bh = NULL;
 999
1000         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
1001
1002         *keyp = nilfs_btree_node_get_key(child, 0);
1003         *ptrp = path[level].bp_newreq.bpr_ptr;
1004 }
1005
1006 static __u64 nilfs_btree_find_near(const struct nilfs_bmap *btree,
1007                                    const struct nilfs_btree_path *path)
1008 {
1009         struct nilfs_btree_node *node;
1010         int level, ncmax;
1011
1012         if (path == NULL)
1013                 return NILFS_BMAP_INVALID_PTR;
1014
1015         /* left sibling */
1016         level = NILFS_BTREE_LEVEL_NODE_MIN;
1017         if (path[level].bp_index > 0) {
1018                 node = nilfs_btree_get_node(btree, path, level, &ncmax);
1019                 return nilfs_btree_node_get_ptr(node,
1020                                                 path[level].bp_index - 1,
1021                                                 ncmax);
1022         }
1023
1024         /* parent */
1025         level = NILFS_BTREE_LEVEL_NODE_MIN + 1;
1026         if (level <= nilfs_btree_height(btree) - 1) {
1027                 node = nilfs_btree_get_node(btree, path, level, &ncmax);
1028                 return nilfs_btree_node_get_ptr(node, path[level].bp_index,
1029                                                 ncmax);
1030         }
1031
1032         return NILFS_BMAP_INVALID_PTR;
1033 }
1034
1035 static __u64 nilfs_btree_find_target_v(const struct nilfs_bmap *btree,
1036                                        const struct nilfs_btree_path *path,
1037                                        __u64 key)
1038 {
1039         __u64 ptr;
1040
1041         ptr = nilfs_bmap_find_target_seq(btree, key);
1042         if (ptr != NILFS_BMAP_INVALID_PTR)
1043                 /* sequential access */
1044                 return ptr;
1045
1046         ptr = nilfs_btree_find_near(btree, path);
1047         if (ptr != NILFS_BMAP_INVALID_PTR)
1048                 /* near */
1049                 return ptr;
1050
1051         /* block group */
1052         return nilfs_bmap_find_target_in_group(btree);
1053 }
1054
1055 static int nilfs_btree_prepare_insert(struct nilfs_bmap *btree,
1056                                       struct nilfs_btree_path *path,
1057                                       int *levelp, __u64 key, __u64 ptr,
1058                                       struct nilfs_bmap_stats *stats)
1059 {
1060         struct buffer_head *bh;
1061         struct nilfs_btree_node *node, *parent, *sib;
1062         __u64 sibptr;
1063         int pindex, level, ncmax, ncblk, ret;
1064         struct inode *dat = NULL;
1065
1066         stats->bs_nblocks = 0;
1067         level = NILFS_BTREE_LEVEL_DATA;
1068
1069         /* allocate a new ptr for data block */
1070         if (NILFS_BMAP_USE_VBN(btree)) {
1071                 path[level].bp_newreq.bpr_ptr =
1072                         nilfs_btree_find_target_v(btree, path, key);
1073                 dat = nilfs_bmap_get_dat(btree);
1074         }
1075
1076         ret = nilfs_bmap_prepare_alloc_ptr(btree, &path[level].bp_newreq, dat);
1077         if (ret < 0)
1078                 goto err_out_data;
1079
1080         ncblk = nilfs_btree_nchildren_per_block(btree);
1081
1082         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
1083              level < nilfs_btree_height(btree) - 1;
1084              level++) {
1085                 node = nilfs_btree_get_nonroot_node(path, level);
1086                 if (nilfs_btree_node_get_nchildren(node) < ncblk) {
1087                         path[level].bp_op = nilfs_btree_do_insert;
1088                         stats->bs_nblocks++;
1089                         goto out;
1090                 }
1091
1092                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1093                 pindex = path[level + 1].bp_index;
1094
1095                 /* left sibling */
1096                 if (pindex > 0) {
1097                         sibptr = nilfs_btree_node_get_ptr(parent, pindex - 1,
1098                                                           ncmax);
1099                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1100                         if (ret < 0)
1101                                 goto err_out_child_node;
1102                         sib = (struct nilfs_btree_node *)bh->b_data;
1103                         if (nilfs_btree_node_get_nchildren(sib) < ncblk) {
1104                                 path[level].bp_sib_bh = bh;
1105                                 path[level].bp_op = nilfs_btree_carry_left;
1106                                 stats->bs_nblocks++;
1107                                 goto out;
1108                         } else {
1109                                 brelse(bh);
1110                         }
1111                 }
1112
1113                 /* right sibling */
1114                 if (pindex < nilfs_btree_node_get_nchildren(parent) - 1) {
1115                         sibptr = nilfs_btree_node_get_ptr(parent, pindex + 1,
1116                                                           ncmax);
1117                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1118                         if (ret < 0)
1119                                 goto err_out_child_node;
1120                         sib = (struct nilfs_btree_node *)bh->b_data;
1121                         if (nilfs_btree_node_get_nchildren(sib) < ncblk) {
1122                                 path[level].bp_sib_bh = bh;
1123                                 path[level].bp_op = nilfs_btree_carry_right;
1124                                 stats->bs_nblocks++;
1125                                 goto out;
1126                         } else {
1127                                 brelse(bh);
1128                         }
1129                 }
1130
1131                 /* split */
1132                 path[level].bp_newreq.bpr_ptr =
1133                         path[level - 1].bp_newreq.bpr_ptr + 1;
1134                 ret = nilfs_bmap_prepare_alloc_ptr(btree,
1135                                                    &path[level].bp_newreq, dat);
1136                 if (ret < 0)
1137                         goto err_out_child_node;
1138                 ret = nilfs_btree_get_new_block(btree,
1139                                                 path[level].bp_newreq.bpr_ptr,
1140                                                 &bh);
1141                 if (ret < 0)
1142                         goto err_out_curr_node;
1143
1144                 stats->bs_nblocks++;
1145
1146                 sib = (struct nilfs_btree_node *)bh->b_data;
1147                 nilfs_btree_node_init(sib, 0, level, 0, ncblk, NULL, NULL);
1148                 path[level].bp_sib_bh = bh;
1149                 path[level].bp_op = nilfs_btree_split;
1150         }
1151
1152         /* root */
1153         node = nilfs_btree_get_root(btree);
1154         if (nilfs_btree_node_get_nchildren(node) <
1155             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1156                 path[level].bp_op = nilfs_btree_do_insert;
1157                 stats->bs_nblocks++;
1158                 goto out;
1159         }
1160
1161         /* grow */
1162         path[level].bp_newreq.bpr_ptr = path[level - 1].bp_newreq.bpr_ptr + 1;
1163         ret = nilfs_bmap_prepare_alloc_ptr(btree, &path[level].bp_newreq, dat);
1164         if (ret < 0)
1165                 goto err_out_child_node;
1166         ret = nilfs_btree_get_new_block(btree, path[level].bp_newreq.bpr_ptr,
1167                                         &bh);
1168         if (ret < 0)
1169                 goto err_out_curr_node;
1170
1171         nilfs_btree_node_init((struct nilfs_btree_node *)bh->b_data,
1172                               0, level, 0, ncblk, NULL, NULL);
1173         path[level].bp_sib_bh = bh;
1174         path[level].bp_op = nilfs_btree_grow;
1175
1176         level++;
1177         path[level].bp_op = nilfs_btree_do_insert;
1178
1179         /* a newly-created node block and a data block are added */
1180         stats->bs_nblocks += 2;
1181
1182         /* success */
1183  out:
1184         *levelp = level;
1185         return ret;
1186
1187         /* error */
1188  err_out_curr_node:
1189         nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1190  err_out_child_node:
1191         for (level--; level > NILFS_BTREE_LEVEL_DATA; level--) {
1192                 nilfs_btnode_delete(path[level].bp_sib_bh);
1193                 nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1194
1195         }
1196
1197         nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1198  err_out_data:
1199         *levelp = level;
1200         stats->bs_nblocks = 0;
1201         return ret;
1202 }
1203
1204 static void nilfs_btree_commit_insert(struct nilfs_bmap *btree,
1205                                       struct nilfs_btree_path *path,
1206                                       int maxlevel, __u64 key, __u64 ptr)
1207 {
1208         struct inode *dat = NULL;
1209         int level;
1210
1211         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
1212         ptr = path[NILFS_BTREE_LEVEL_DATA].bp_newreq.bpr_ptr;
1213         if (NILFS_BMAP_USE_VBN(btree)) {
1214                 nilfs_bmap_set_target_v(btree, key, ptr);
1215                 dat = nilfs_bmap_get_dat(btree);
1216         }
1217
1218         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
1219                 nilfs_bmap_commit_alloc_ptr(btree,
1220                                             &path[level - 1].bp_newreq, dat);
1221                 path[level].bp_op(btree, path, level, &key, &ptr);
1222         }
1223
1224         if (!nilfs_bmap_dirty(btree))
1225                 nilfs_bmap_set_dirty(btree);
1226 }
1227
1228 static int nilfs_btree_insert(struct nilfs_bmap *btree, __u64 key, __u64 ptr)
1229 {
1230         struct nilfs_btree_path *path;
1231         struct nilfs_bmap_stats stats;
1232         int level, ret;
1233
1234         path = nilfs_btree_alloc_path();
1235         if (path == NULL)
1236                 return -ENOMEM;
1237
1238         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
1239                                     NILFS_BTREE_LEVEL_NODE_MIN, 0);
1240         if (ret != -ENOENT) {
1241                 if (ret == 0)
1242                         ret = -EEXIST;
1243                 goto out;
1244         }
1245
1246         ret = nilfs_btree_prepare_insert(btree, path, &level, key, ptr, &stats);
1247         if (ret < 0)
1248                 goto out;
1249         nilfs_btree_commit_insert(btree, path, level, key, ptr);
1250         nilfs_inode_add_blocks(btree->b_inode, stats.bs_nblocks);
1251
1252  out:
1253         nilfs_btree_free_path(path);
1254         return ret;
1255 }
1256
1257 static void nilfs_btree_do_delete(struct nilfs_bmap *btree,
1258                                   struct nilfs_btree_path *path,
1259                                   int level, __u64 *keyp, __u64 *ptrp)
1260 {
1261         struct nilfs_btree_node *node;
1262         int ncblk;
1263
1264         if (level < nilfs_btree_height(btree) - 1) {
1265                 node = nilfs_btree_get_nonroot_node(path, level);
1266                 ncblk = nilfs_btree_nchildren_per_block(btree);
1267                 nilfs_btree_node_delete(node, path[level].bp_index,
1268                                         keyp, ptrp, ncblk);
1269                 if (!buffer_dirty(path[level].bp_bh))
1270                         mark_buffer_dirty(path[level].bp_bh);
1271                 if (path[level].bp_index == 0)
1272                         nilfs_btree_promote_key(btree, path, level + 1,
1273                                 nilfs_btree_node_get_key(node, 0));
1274         } else {
1275                 node = nilfs_btree_get_root(btree);
1276                 nilfs_btree_node_delete(node, path[level].bp_index,
1277                                         keyp, ptrp,
1278                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
1279         }
1280 }
1281
1282 static void nilfs_btree_borrow_left(struct nilfs_bmap *btree,
1283                                     struct nilfs_btree_path *path,
1284                                     int level, __u64 *keyp, __u64 *ptrp)
1285 {
1286         struct nilfs_btree_node *node, *left;
1287         int nchildren, lnchildren, n, ncblk;
1288
1289         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1290
1291         node = nilfs_btree_get_nonroot_node(path, level);
1292         left = nilfs_btree_get_sib_node(path, level);
1293         nchildren = nilfs_btree_node_get_nchildren(node);
1294         lnchildren = nilfs_btree_node_get_nchildren(left);
1295         ncblk = nilfs_btree_nchildren_per_block(btree);
1296
1297         n = (nchildren + lnchildren) / 2 - nchildren;
1298
1299         nilfs_btree_node_move_right(left, node, n, ncblk, ncblk);
1300
1301         if (!buffer_dirty(path[level].bp_bh))
1302                 mark_buffer_dirty(path[level].bp_bh);
1303         if (!buffer_dirty(path[level].bp_sib_bh))
1304                 mark_buffer_dirty(path[level].bp_sib_bh);
1305
1306         nilfs_btree_promote_key(btree, path, level + 1,
1307                                 nilfs_btree_node_get_key(node, 0));
1308
1309         brelse(path[level].bp_sib_bh);
1310         path[level].bp_sib_bh = NULL;
1311         path[level].bp_index += n;
1312 }
1313
1314 static void nilfs_btree_borrow_right(struct nilfs_bmap *btree,
1315                                      struct nilfs_btree_path *path,
1316                                      int level, __u64 *keyp, __u64 *ptrp)
1317 {
1318         struct nilfs_btree_node *node, *right;
1319         int nchildren, rnchildren, n, ncblk;
1320
1321         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1322
1323         node = nilfs_btree_get_nonroot_node(path, level);
1324         right = nilfs_btree_get_sib_node(path, level);
1325         nchildren = nilfs_btree_node_get_nchildren(node);
1326         rnchildren = nilfs_btree_node_get_nchildren(right);
1327         ncblk = nilfs_btree_nchildren_per_block(btree);
1328
1329         n = (nchildren + rnchildren) / 2 - nchildren;
1330
1331         nilfs_btree_node_move_left(node, right, n, ncblk, ncblk);
1332
1333         if (!buffer_dirty(path[level].bp_bh))
1334                 mark_buffer_dirty(path[level].bp_bh);
1335         if (!buffer_dirty(path[level].bp_sib_bh))
1336                 mark_buffer_dirty(path[level].bp_sib_bh);
1337
1338         path[level + 1].bp_index++;
1339         nilfs_btree_promote_key(btree, path, level + 1,
1340                                 nilfs_btree_node_get_key(right, 0));
1341         path[level + 1].bp_index--;
1342
1343         brelse(path[level].bp_sib_bh);
1344         path[level].bp_sib_bh = NULL;
1345 }
1346
1347 static void nilfs_btree_concat_left(struct nilfs_bmap *btree,
1348                                     struct nilfs_btree_path *path,
1349                                     int level, __u64 *keyp, __u64 *ptrp)
1350 {
1351         struct nilfs_btree_node *node, *left;
1352         int n, ncblk;
1353
1354         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1355
1356         node = nilfs_btree_get_nonroot_node(path, level);
1357         left = nilfs_btree_get_sib_node(path, level);
1358         ncblk = nilfs_btree_nchildren_per_block(btree);
1359
1360         n = nilfs_btree_node_get_nchildren(node);
1361
1362         nilfs_btree_node_move_left(left, node, n, ncblk, ncblk);
1363
1364         if (!buffer_dirty(path[level].bp_sib_bh))
1365                 mark_buffer_dirty(path[level].bp_sib_bh);
1366
1367         nilfs_btnode_delete(path[level].bp_bh);
1368         path[level].bp_bh = path[level].bp_sib_bh;
1369         path[level].bp_sib_bh = NULL;
1370         path[level].bp_index += nilfs_btree_node_get_nchildren(left);
1371 }
1372
1373 static void nilfs_btree_concat_right(struct nilfs_bmap *btree,
1374                                      struct nilfs_btree_path *path,
1375                                      int level, __u64 *keyp, __u64 *ptrp)
1376 {
1377         struct nilfs_btree_node *node, *right;
1378         int n, ncblk;
1379
1380         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1381
1382         node = nilfs_btree_get_nonroot_node(path, level);
1383         right = nilfs_btree_get_sib_node(path, level);
1384         ncblk = nilfs_btree_nchildren_per_block(btree);
1385
1386         n = nilfs_btree_node_get_nchildren(right);
1387
1388         nilfs_btree_node_move_left(node, right, n, ncblk, ncblk);
1389
1390         if (!buffer_dirty(path[level].bp_bh))
1391                 mark_buffer_dirty(path[level].bp_bh);
1392
1393         nilfs_btnode_delete(path[level].bp_sib_bh);
1394         path[level].bp_sib_bh = NULL;
1395         path[level + 1].bp_index++;
1396 }
1397
1398 static void nilfs_btree_shrink(struct nilfs_bmap *btree,
1399                                struct nilfs_btree_path *path,
1400                                int level, __u64 *keyp, __u64 *ptrp)
1401 {
1402         struct nilfs_btree_node *root, *child;
1403         int n, ncblk;
1404
1405         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1406
1407         root = nilfs_btree_get_root(btree);
1408         child = nilfs_btree_get_nonroot_node(path, level);
1409         ncblk = nilfs_btree_nchildren_per_block(btree);
1410
1411         nilfs_btree_node_delete(root, 0, NULL, NULL,
1412                                 NILFS_BTREE_ROOT_NCHILDREN_MAX);
1413         nilfs_btree_node_set_level(root, level);
1414         n = nilfs_btree_node_get_nchildren(child);
1415         nilfs_btree_node_move_left(root, child, n,
1416                                    NILFS_BTREE_ROOT_NCHILDREN_MAX, ncblk);
1417
1418         nilfs_btnode_delete(path[level].bp_bh);
1419         path[level].bp_bh = NULL;
1420 }
1421
1422 static void nilfs_btree_nop(struct nilfs_bmap *btree,
1423                             struct nilfs_btree_path *path,
1424                             int level, __u64 *keyp, __u64 *ptrp)
1425 {
1426 }
1427
1428 static int nilfs_btree_prepare_delete(struct nilfs_bmap *btree,
1429                                       struct nilfs_btree_path *path,
1430                                       int *levelp,
1431                                       struct nilfs_bmap_stats *stats,
1432                                       struct inode *dat)
1433 {
1434         struct buffer_head *bh;
1435         struct nilfs_btree_node *node, *parent, *sib;
1436         __u64 sibptr;
1437         int pindex, dindex, level, ncmin, ncmax, ncblk, ret;
1438
1439         ret = 0;
1440         stats->bs_nblocks = 0;
1441         ncmin = NILFS_BTREE_NODE_NCHILDREN_MIN(nilfs_btree_node_size(btree));
1442         ncblk = nilfs_btree_nchildren_per_block(btree);
1443
1444         for (level = NILFS_BTREE_LEVEL_NODE_MIN, dindex = path[level].bp_index;
1445              level < nilfs_btree_height(btree) - 1;
1446              level++) {
1447                 node = nilfs_btree_get_nonroot_node(path, level);
1448                 path[level].bp_oldreq.bpr_ptr =
1449                         nilfs_btree_node_get_ptr(node, dindex, ncblk);
1450                 ret = nilfs_bmap_prepare_end_ptr(btree,
1451                                                  &path[level].bp_oldreq, dat);
1452                 if (ret < 0)
1453                         goto err_out_child_node;
1454
1455                 if (nilfs_btree_node_get_nchildren(node) > ncmin) {
1456                         path[level].bp_op = nilfs_btree_do_delete;
1457                         stats->bs_nblocks++;
1458                         goto out;
1459                 }
1460
1461                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1462                 pindex = path[level + 1].bp_index;
1463                 dindex = pindex;
1464
1465                 if (pindex > 0) {
1466                         /* left sibling */
1467                         sibptr = nilfs_btree_node_get_ptr(parent, pindex - 1,
1468                                                           ncmax);
1469                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1470                         if (ret < 0)
1471                                 goto err_out_curr_node;
1472                         sib = (struct nilfs_btree_node *)bh->b_data;
1473                         if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
1474                                 path[level].bp_sib_bh = bh;
1475                                 path[level].bp_op = nilfs_btree_borrow_left;
1476                                 stats->bs_nblocks++;
1477                                 goto out;
1478                         } else {
1479                                 path[level].bp_sib_bh = bh;
1480                                 path[level].bp_op = nilfs_btree_concat_left;
1481                                 stats->bs_nblocks++;
1482                                 /* continue; */
1483                         }
1484                 } else if (pindex <
1485                            nilfs_btree_node_get_nchildren(parent) - 1) {
1486                         /* right sibling */
1487                         sibptr = nilfs_btree_node_get_ptr(parent, pindex + 1,
1488                                                           ncmax);
1489                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1490                         if (ret < 0)
1491                                 goto err_out_curr_node;
1492                         sib = (struct nilfs_btree_node *)bh->b_data;
1493                         if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
1494                                 path[level].bp_sib_bh = bh;
1495                                 path[level].bp_op = nilfs_btree_borrow_right;
1496                                 stats->bs_nblocks++;
1497                                 goto out;
1498                         } else {
1499                                 path[level].bp_sib_bh = bh;
1500                                 path[level].bp_op = nilfs_btree_concat_right;
1501                                 stats->bs_nblocks++;
1502                                 /*
1503                                  * When merging right sibling node
1504                                  * into the current node, pointer to
1505                                  * the right sibling node must be
1506                                  * terminated instead.  The adjustment
1507                                  * below is required for that.
1508                                  */
1509                                 dindex = pindex + 1;
1510                                 /* continue; */
1511                         }
1512                 } else {
1513                         /* no siblings */
1514                         /* the only child of the root node */
1515                         WARN_ON(level != nilfs_btree_height(btree) - 2);
1516                         if (nilfs_btree_node_get_nchildren(node) - 1 <=
1517                             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1518                                 path[level].bp_op = nilfs_btree_shrink;
1519                                 stats->bs_nblocks += 2;
1520                                 level++;
1521                                 path[level].bp_op = nilfs_btree_nop;
1522                                 goto shrink_root_child;
1523                         } else {
1524                                 path[level].bp_op = nilfs_btree_do_delete;
1525                                 stats->bs_nblocks++;
1526                                 goto out;
1527                         }
1528                 }
1529         }
1530
1531         /* child of the root node is deleted */
1532         path[level].bp_op = nilfs_btree_do_delete;
1533         stats->bs_nblocks++;
1534
1535 shrink_root_child:
1536         node = nilfs_btree_get_root(btree);
1537         path[level].bp_oldreq.bpr_ptr =
1538                 nilfs_btree_node_get_ptr(node, dindex,
1539                                          NILFS_BTREE_ROOT_NCHILDREN_MAX);
1540
1541         ret = nilfs_bmap_prepare_end_ptr(btree, &path[level].bp_oldreq, dat);
1542         if (ret < 0)
1543                 goto err_out_child_node;
1544
1545         /* success */
1546  out:
1547         *levelp = level;
1548         return ret;
1549
1550         /* error */
1551  err_out_curr_node:
1552         nilfs_bmap_abort_end_ptr(btree, &path[level].bp_oldreq, dat);
1553  err_out_child_node:
1554         for (level--; level >= NILFS_BTREE_LEVEL_NODE_MIN; level--) {
1555                 brelse(path[level].bp_sib_bh);
1556                 nilfs_bmap_abort_end_ptr(btree, &path[level].bp_oldreq, dat);
1557         }
1558         *levelp = level;
1559         stats->bs_nblocks = 0;
1560         return ret;
1561 }
1562
1563 static void nilfs_btree_commit_delete(struct nilfs_bmap *btree,
1564                                       struct nilfs_btree_path *path,
1565                                       int maxlevel, struct inode *dat)
1566 {
1567         int level;
1568
1569         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
1570                 nilfs_bmap_commit_end_ptr(btree, &path[level].bp_oldreq, dat);
1571                 path[level].bp_op(btree, path, level, NULL, NULL);
1572         }
1573
1574         if (!nilfs_bmap_dirty(btree))
1575                 nilfs_bmap_set_dirty(btree);
1576 }
1577
1578 static int nilfs_btree_delete(struct nilfs_bmap *btree, __u64 key)
1579
1580 {
1581         struct nilfs_btree_path *path;
1582         struct nilfs_bmap_stats stats;
1583         struct inode *dat;
1584         int level, ret;
1585
1586         path = nilfs_btree_alloc_path();
1587         if (path == NULL)
1588                 return -ENOMEM;
1589
1590         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
1591                                     NILFS_BTREE_LEVEL_NODE_MIN, 0);
1592         if (ret < 0)
1593                 goto out;
1594
1595
1596         dat = NILFS_BMAP_USE_VBN(btree) ? nilfs_bmap_get_dat(btree) : NULL;
1597
1598         ret = nilfs_btree_prepare_delete(btree, path, &level, &stats, dat);
1599         if (ret < 0)
1600                 goto out;
1601         nilfs_btree_commit_delete(btree, path, level, dat);
1602         nilfs_inode_sub_blocks(btree->b_inode, stats.bs_nblocks);
1603
1604 out:
1605         nilfs_btree_free_path(path);
1606         return ret;
1607 }
1608
1609 static int nilfs_btree_seek_key(const struct nilfs_bmap *btree, __u64 start,
1610                                 __u64 *keyp)
1611 {
1612         struct nilfs_btree_path *path;
1613         const int minlevel = NILFS_BTREE_LEVEL_NODE_MIN;
1614         int ret;
1615
1616         path = nilfs_btree_alloc_path();
1617         if (!path)
1618                 return -ENOMEM;
1619
1620         ret = nilfs_btree_do_lookup(btree, path, start, NULL, minlevel, 0);
1621         if (!ret)
1622                 *keyp = start;
1623         else if (ret == -ENOENT)
1624                 ret = nilfs_btree_get_next_key(btree, path, minlevel, keyp);
1625
1626         nilfs_btree_free_path(path);
1627         return ret;
1628 }
1629
1630 static int nilfs_btree_last_key(const struct nilfs_bmap *btree, __u64 *keyp)
1631 {
1632         struct nilfs_btree_path *path;
1633         int ret;
1634
1635         path = nilfs_btree_alloc_path();
1636         if (path == NULL)
1637                 return -ENOMEM;
1638
1639         ret = nilfs_btree_do_lookup_last(btree, path, keyp, NULL);
1640
1641         nilfs_btree_free_path(path);
1642
1643         return ret;
1644 }
1645
1646 static int nilfs_btree_check_delete(struct nilfs_bmap *btree, __u64 key)
1647 {
1648         struct buffer_head *bh;
1649         struct nilfs_btree_node *root, *node;
1650         __u64 maxkey, nextmaxkey;
1651         __u64 ptr;
1652         int nchildren, ret;
1653
1654         root = nilfs_btree_get_root(btree);
1655         switch (nilfs_btree_height(btree)) {
1656         case 2:
1657                 bh = NULL;
1658                 node = root;
1659                 break;
1660         case 3:
1661                 nchildren = nilfs_btree_node_get_nchildren(root);
1662                 if (nchildren > 1)
1663                         return 0;
1664                 ptr = nilfs_btree_node_get_ptr(root, nchildren - 1,
1665                                                NILFS_BTREE_ROOT_NCHILDREN_MAX);
1666                 ret = nilfs_btree_get_block(btree, ptr, &bh);
1667                 if (ret < 0)
1668                         return ret;
1669                 node = (struct nilfs_btree_node *)bh->b_data;
1670                 break;
1671         default:
1672                 return 0;
1673         }
1674
1675         nchildren = nilfs_btree_node_get_nchildren(node);
1676         maxkey = nilfs_btree_node_get_key(node, nchildren - 1);
1677         nextmaxkey = (nchildren > 1) ?
1678                 nilfs_btree_node_get_key(node, nchildren - 2) : 0;
1679         if (bh != NULL)
1680                 brelse(bh);
1681
1682         return (maxkey == key) && (nextmaxkey < NILFS_BMAP_LARGE_LOW);
1683 }
1684
1685 static int nilfs_btree_gather_data(struct nilfs_bmap *btree,
1686                                    __u64 *keys, __u64 *ptrs, int nitems)
1687 {
1688         struct buffer_head *bh;
1689         struct nilfs_btree_node *node, *root;
1690         __le64 *dkeys;
1691         __le64 *dptrs;
1692         __u64 ptr;
1693         int nchildren, ncmax, i, ret;
1694
1695         root = nilfs_btree_get_root(btree);
1696         switch (nilfs_btree_height(btree)) {
1697         case 2:
1698                 bh = NULL;
1699                 node = root;
1700                 ncmax = NILFS_BTREE_ROOT_NCHILDREN_MAX;
1701                 break;
1702         case 3:
1703                 nchildren = nilfs_btree_node_get_nchildren(root);
1704                 WARN_ON(nchildren > 1);
1705                 ptr = nilfs_btree_node_get_ptr(root, nchildren - 1,
1706                                                NILFS_BTREE_ROOT_NCHILDREN_MAX);
1707                 ret = nilfs_btree_get_block(btree, ptr, &bh);
1708                 if (ret < 0)
1709                         return ret;
1710                 node = (struct nilfs_btree_node *)bh->b_data;
1711                 ncmax = nilfs_btree_nchildren_per_block(btree);
1712                 break;
1713         default:
1714                 node = NULL;
1715                 return -EINVAL;
1716         }
1717
1718         nchildren = nilfs_btree_node_get_nchildren(node);
1719         if (nchildren < nitems)
1720                 nitems = nchildren;
1721         dkeys = nilfs_btree_node_dkeys(node);
1722         dptrs = nilfs_btree_node_dptrs(node, ncmax);
1723         for (i = 0; i < nitems; i++) {
1724                 keys[i] = le64_to_cpu(dkeys[i]);
1725                 ptrs[i] = le64_to_cpu(dptrs[i]);
1726         }
1727
1728         if (bh != NULL)
1729                 brelse(bh);
1730
1731         return nitems;
1732 }
1733
1734 static int
1735 nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *btree, __u64 key,
1736                                        union nilfs_bmap_ptr_req *dreq,
1737                                        union nilfs_bmap_ptr_req *nreq,
1738                                        struct buffer_head **bhp,
1739                                        struct nilfs_bmap_stats *stats)
1740 {
1741         struct buffer_head *bh;
1742         struct inode *dat = NULL;
1743         int ret;
1744
1745         stats->bs_nblocks = 0;
1746
1747         /* for data */
1748         /* cannot find near ptr */
1749         if (NILFS_BMAP_USE_VBN(btree)) {
1750                 dreq->bpr_ptr = nilfs_btree_find_target_v(btree, NULL, key);
1751                 dat = nilfs_bmap_get_dat(btree);
1752         }
1753
1754         ret = nilfs_bmap_prepare_alloc_ptr(btree, dreq, dat);
1755         if (ret < 0)
1756                 return ret;
1757
1758         *bhp = NULL;
1759         stats->bs_nblocks++;
1760         if (nreq != NULL) {
1761                 nreq->bpr_ptr = dreq->bpr_ptr + 1;
1762                 ret = nilfs_bmap_prepare_alloc_ptr(btree, nreq, dat);
1763                 if (ret < 0)
1764                         goto err_out_dreq;
1765
1766                 ret = nilfs_btree_get_new_block(btree, nreq->bpr_ptr, &bh);
1767                 if (ret < 0)
1768                         goto err_out_nreq;
1769
1770                 *bhp = bh;
1771                 stats->bs_nblocks++;
1772         }
1773
1774         /* success */
1775         return 0;
1776
1777         /* error */
1778  err_out_nreq:
1779         nilfs_bmap_abort_alloc_ptr(btree, nreq, dat);
1780  err_out_dreq:
1781         nilfs_bmap_abort_alloc_ptr(btree, dreq, dat);
1782         stats->bs_nblocks = 0;
1783         return ret;
1784
1785 }
1786
1787 static void
1788 nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *btree,
1789                                       __u64 key, __u64 ptr,
1790                                       const __u64 *keys, const __u64 *ptrs,
1791                                       int n,
1792                                       union nilfs_bmap_ptr_req *dreq,
1793                                       union nilfs_bmap_ptr_req *nreq,
1794                                       struct buffer_head *bh)
1795 {
1796         struct nilfs_btree_node *node;
1797         struct inode *dat;
1798         __u64 tmpptr;
1799         int ncblk;
1800
1801         /* free resources */
1802         if (btree->b_ops->bop_clear != NULL)
1803                 btree->b_ops->bop_clear(btree);
1804
1805         /* ptr must be a pointer to a buffer head. */
1806         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
1807
1808         /* convert and insert */
1809         dat = NILFS_BMAP_USE_VBN(btree) ? nilfs_bmap_get_dat(btree) : NULL;
1810         __nilfs_btree_init(btree);
1811         if (nreq != NULL) {
1812                 nilfs_bmap_commit_alloc_ptr(btree, dreq, dat);
1813                 nilfs_bmap_commit_alloc_ptr(btree, nreq, dat);
1814
1815                 /* create child node at level 1 */
1816                 node = (struct nilfs_btree_node *)bh->b_data;
1817                 ncblk = nilfs_btree_nchildren_per_block(btree);
1818                 nilfs_btree_node_init(node, 0, 1, n, ncblk, keys, ptrs);
1819                 nilfs_btree_node_insert(node, n, key, dreq->bpr_ptr, ncblk);
1820                 if (!buffer_dirty(bh))
1821                         mark_buffer_dirty(bh);
1822                 if (!nilfs_bmap_dirty(btree))
1823                         nilfs_bmap_set_dirty(btree);
1824
1825                 brelse(bh);
1826
1827                 /* create root node at level 2 */
1828                 node = nilfs_btree_get_root(btree);
1829                 tmpptr = nreq->bpr_ptr;
1830                 nilfs_btree_node_init(node, NILFS_BTREE_NODE_ROOT, 2, 1,
1831                                       NILFS_BTREE_ROOT_NCHILDREN_MAX,
1832                                       &keys[0], &tmpptr);
1833         } else {
1834                 nilfs_bmap_commit_alloc_ptr(btree, dreq, dat);
1835
1836                 /* create root node at level 1 */
1837                 node = nilfs_btree_get_root(btree);
1838                 nilfs_btree_node_init(node, NILFS_BTREE_NODE_ROOT, 1, n,
1839                                       NILFS_BTREE_ROOT_NCHILDREN_MAX,
1840                                       keys, ptrs);
1841                 nilfs_btree_node_insert(node, n, key, dreq->bpr_ptr,
1842                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
1843                 if (!nilfs_bmap_dirty(btree))
1844                         nilfs_bmap_set_dirty(btree);
1845         }
1846
1847         if (NILFS_BMAP_USE_VBN(btree))
1848                 nilfs_bmap_set_target_v(btree, key, dreq->bpr_ptr);
1849 }
1850
1851 /**
1852  * nilfs_btree_convert_and_insert -
1853  * @bmap:
1854  * @key:
1855  * @ptr:
1856  * @keys:
1857  * @ptrs:
1858  * @n:
1859  */
1860 int nilfs_btree_convert_and_insert(struct nilfs_bmap *btree,
1861                                    __u64 key, __u64 ptr,
1862                                    const __u64 *keys, const __u64 *ptrs, int n)
1863 {
1864         struct buffer_head *bh = NULL;
1865         union nilfs_bmap_ptr_req dreq, nreq, *di, *ni;
1866         struct nilfs_bmap_stats stats;
1867         int ret;
1868
1869         if (n + 1 <= NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1870                 di = &dreq;
1871                 ni = NULL;
1872         } else if ((n + 1) <= NILFS_BTREE_NODE_NCHILDREN_MAX(
1873                            nilfs_btree_node_size(btree))) {
1874                 di = &dreq;
1875                 ni = &nreq;
1876         } else {
1877                 di = NULL;
1878                 ni = NULL;
1879                 BUG();
1880         }
1881
1882         ret = nilfs_btree_prepare_convert_and_insert(btree, key, di, ni, &bh,
1883                                                      &stats);
1884         if (ret < 0)
1885                 return ret;
1886         nilfs_btree_commit_convert_and_insert(btree, key, ptr, keys, ptrs, n,
1887                                               di, ni, bh);
1888         nilfs_inode_add_blocks(btree->b_inode, stats.bs_nblocks);
1889         return 0;
1890 }
1891
1892 static int nilfs_btree_propagate_p(struct nilfs_bmap *btree,
1893                                    struct nilfs_btree_path *path,
1894                                    int level,
1895                                    struct buffer_head *bh)
1896 {
1897         while ((++level < nilfs_btree_height(btree) - 1) &&
1898                !buffer_dirty(path[level].bp_bh))
1899                 mark_buffer_dirty(path[level].bp_bh);
1900
1901         return 0;
1902 }
1903
1904 static int nilfs_btree_prepare_update_v(struct nilfs_bmap *btree,
1905                                         struct nilfs_btree_path *path,
1906                                         int level, struct inode *dat)
1907 {
1908         struct nilfs_btree_node *parent;
1909         int ncmax, ret;
1910
1911         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1912         path[level].bp_oldreq.bpr_ptr =
1913                 nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
1914                                          ncmax);
1915         path[level].bp_newreq.bpr_ptr = path[level].bp_oldreq.bpr_ptr + 1;
1916         ret = nilfs_dat_prepare_update(dat, &path[level].bp_oldreq.bpr_req,
1917                                        &path[level].bp_newreq.bpr_req);
1918         if (ret < 0)
1919                 return ret;
1920
1921         if (buffer_nilfs_node(path[level].bp_bh)) {
1922                 path[level].bp_ctxt.oldkey = path[level].bp_oldreq.bpr_ptr;
1923                 path[level].bp_ctxt.newkey = path[level].bp_newreq.bpr_ptr;
1924                 path[level].bp_ctxt.bh = path[level].bp_bh;
1925                 ret = nilfs_btnode_prepare_change_key(
1926                         &NILFS_BMAP_I(btree)->i_btnode_cache,
1927                         &path[level].bp_ctxt);
1928                 if (ret < 0) {
1929                         nilfs_dat_abort_update(dat,
1930                                                &path[level].bp_oldreq.bpr_req,
1931                                                &path[level].bp_newreq.bpr_req);
1932                         return ret;
1933                 }
1934         }
1935
1936         return 0;
1937 }
1938
1939 static void nilfs_btree_commit_update_v(struct nilfs_bmap *btree,
1940                                         struct nilfs_btree_path *path,
1941                                         int level, struct inode *dat)
1942 {
1943         struct nilfs_btree_node *parent;
1944         int ncmax;
1945
1946         nilfs_dat_commit_update(dat, &path[level].bp_oldreq.bpr_req,
1947                                 &path[level].bp_newreq.bpr_req,
1948                                 btree->b_ptr_type == NILFS_BMAP_PTR_VS);
1949
1950         if (buffer_nilfs_node(path[level].bp_bh)) {
1951                 nilfs_btnode_commit_change_key(
1952                         &NILFS_BMAP_I(btree)->i_btnode_cache,
1953                         &path[level].bp_ctxt);
1954                 path[level].bp_bh = path[level].bp_ctxt.bh;
1955         }
1956         set_buffer_nilfs_volatile(path[level].bp_bh);
1957
1958         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1959         nilfs_btree_node_set_ptr(parent, path[level + 1].bp_index,
1960                                  path[level].bp_newreq.bpr_ptr, ncmax);
1961 }
1962
1963 static void nilfs_btree_abort_update_v(struct nilfs_bmap *btree,
1964                                        struct nilfs_btree_path *path,
1965                                        int level, struct inode *dat)
1966 {
1967         nilfs_dat_abort_update(dat, &path[level].bp_oldreq.bpr_req,
1968                                &path[level].bp_newreq.bpr_req);
1969         if (buffer_nilfs_node(path[level].bp_bh))
1970                 nilfs_btnode_abort_change_key(
1971                         &NILFS_BMAP_I(btree)->i_btnode_cache,
1972                         &path[level].bp_ctxt);
1973 }
1974
1975 static int nilfs_btree_prepare_propagate_v(struct nilfs_bmap *btree,
1976                                            struct nilfs_btree_path *path,
1977                                            int minlevel, int *maxlevelp,
1978                                            struct inode *dat)
1979 {
1980         int level, ret;
1981
1982         level = minlevel;
1983         if (!buffer_nilfs_volatile(path[level].bp_bh)) {
1984                 ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
1985                 if (ret < 0)
1986                         return ret;
1987         }
1988         while ((++level < nilfs_btree_height(btree) - 1) &&
1989                !buffer_dirty(path[level].bp_bh)) {
1990
1991                 WARN_ON(buffer_nilfs_volatile(path[level].bp_bh));
1992                 ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
1993                 if (ret < 0)
1994                         goto out;
1995         }
1996
1997         /* success */
1998         *maxlevelp = level - 1;
1999         return 0;
2000
2001         /* error */
2002  out:
2003         while (--level > minlevel)
2004                 nilfs_btree_abort_update_v(btree, path, level, dat);
2005         if (!buffer_nilfs_volatile(path[level].bp_bh))
2006                 nilfs_btree_abort_update_v(btree, path, level, dat);
2007         return ret;
2008 }
2009
2010 static void nilfs_btree_commit_propagate_v(struct nilfs_bmap *btree,
2011                                            struct nilfs_btree_path *path,
2012                                            int minlevel, int maxlevel,
2013                                            struct buffer_head *bh,
2014                                            struct inode *dat)
2015 {
2016         int level;
2017
2018         if (!buffer_nilfs_volatile(path[minlevel].bp_bh))
2019                 nilfs_btree_commit_update_v(btree, path, minlevel, dat);
2020
2021         for (level = minlevel + 1; level <= maxlevel; level++)
2022                 nilfs_btree_commit_update_v(btree, path, level, dat);
2023 }
2024
2025 static int nilfs_btree_propagate_v(struct nilfs_bmap *btree,
2026                                    struct nilfs_btree_path *path,
2027                                    int level, struct buffer_head *bh)
2028 {
2029         int maxlevel = 0, ret;
2030         struct nilfs_btree_node *parent;
2031         struct inode *dat = nilfs_bmap_get_dat(btree);
2032         __u64 ptr;
2033         int ncmax;
2034
2035         get_bh(bh);
2036         path[level].bp_bh = bh;
2037         ret = nilfs_btree_prepare_propagate_v(btree, path, level, &maxlevel,
2038                                               dat);
2039         if (ret < 0)
2040                 goto out;
2041
2042         if (buffer_nilfs_volatile(path[level].bp_bh)) {
2043                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2044                 ptr = nilfs_btree_node_get_ptr(parent,
2045                                                path[level + 1].bp_index,
2046                                                ncmax);
2047                 ret = nilfs_dat_mark_dirty(dat, ptr);
2048                 if (ret < 0)
2049                         goto out;
2050         }
2051
2052         nilfs_btree_commit_propagate_v(btree, path, level, maxlevel, bh, dat);
2053
2054  out:
2055         brelse(path[level].bp_bh);
2056         path[level].bp_bh = NULL;
2057         return ret;
2058 }
2059
2060 static int nilfs_btree_propagate(struct nilfs_bmap *btree,
2061                                  struct buffer_head *bh)
2062 {
2063         struct nilfs_btree_path *path;
2064         struct nilfs_btree_node *node;
2065         __u64 key;
2066         int level, ret;
2067
2068         WARN_ON(!buffer_dirty(bh));
2069
2070         path = nilfs_btree_alloc_path();
2071         if (path == NULL)
2072                 return -ENOMEM;
2073
2074         if (buffer_nilfs_node(bh)) {
2075                 node = (struct nilfs_btree_node *)bh->b_data;
2076                 key = nilfs_btree_node_get_key(node, 0);
2077                 level = nilfs_btree_node_get_level(node);
2078         } else {
2079                 key = nilfs_bmap_data_get_key(btree, bh);
2080                 level = NILFS_BTREE_LEVEL_DATA;
2081         }
2082
2083         ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
2084         if (ret < 0) {
2085                 if (unlikely(ret == -ENOENT))
2086                         nilfs_msg(btree->b_inode->i_sb, KERN_CRIT,
2087                                   "writing node/leaf block does not appear in b-tree (ino=%lu) at key=%llu, level=%d",
2088                                   btree->b_inode->i_ino,
2089                                   (unsigned long long)key, level);
2090                 goto out;
2091         }
2092
2093         ret = NILFS_BMAP_USE_VBN(btree) ?
2094                 nilfs_btree_propagate_v(btree, path, level, bh) :
2095                 nilfs_btree_propagate_p(btree, path, level, bh);
2096
2097  out:
2098         nilfs_btree_free_path(path);
2099
2100         return ret;
2101 }
2102
2103 static int nilfs_btree_propagate_gc(struct nilfs_bmap *btree,
2104                                     struct buffer_head *bh)
2105 {
2106         return nilfs_dat_mark_dirty(nilfs_bmap_get_dat(btree), bh->b_blocknr);
2107 }
2108
2109 static void nilfs_btree_add_dirty_buffer(struct nilfs_bmap *btree,
2110                                          struct list_head *lists,
2111                                          struct buffer_head *bh)
2112 {
2113         struct list_head *head;
2114         struct buffer_head *cbh;
2115         struct nilfs_btree_node *node, *cnode;
2116         __u64 key, ckey;
2117         int level;
2118
2119         get_bh(bh);
2120         node = (struct nilfs_btree_node *)bh->b_data;
2121         key = nilfs_btree_node_get_key(node, 0);
2122         level = nilfs_btree_node_get_level(node);
2123         if (level < NILFS_BTREE_LEVEL_NODE_MIN ||
2124             level >= NILFS_BTREE_LEVEL_MAX) {
2125                 dump_stack();
2126                 nilfs_msg(btree->b_inode->i_sb, KERN_WARNING,
2127                           "invalid btree level: %d (key=%llu, ino=%lu, blocknr=%llu)",
2128                           level, (unsigned long long)key,
2129                           btree->b_inode->i_ino,
2130                           (unsigned long long)bh->b_blocknr);
2131                 return;
2132         }
2133
2134         list_for_each(head, &lists[level]) {
2135                 cbh = list_entry(head, struct buffer_head, b_assoc_buffers);
2136                 cnode = (struct nilfs_btree_node *)cbh->b_data;
2137                 ckey = nilfs_btree_node_get_key(cnode, 0);
2138                 if (key < ckey)
2139                         break;
2140         }
2141         list_add_tail(&bh->b_assoc_buffers, head);
2142 }
2143
2144 static void nilfs_btree_lookup_dirty_buffers(struct nilfs_bmap *btree,
2145                                              struct list_head *listp)
2146 {
2147         struct address_space *btcache = &NILFS_BMAP_I(btree)->i_btnode_cache;
2148         struct list_head lists[NILFS_BTREE_LEVEL_MAX];
2149         struct pagevec pvec;
2150         struct buffer_head *bh, *head;
2151         pgoff_t index = 0;
2152         int level, i;
2153
2154         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
2155              level < NILFS_BTREE_LEVEL_MAX;
2156              level++)
2157                 INIT_LIST_HEAD(&lists[level]);
2158
2159         pagevec_init(&pvec, 0);
2160
2161         while (pagevec_lookup_tag(&pvec, btcache, &index, PAGECACHE_TAG_DIRTY,
2162                                   PAGEVEC_SIZE)) {
2163                 for (i = 0; i < pagevec_count(&pvec); i++) {
2164                         bh = head = page_buffers(pvec.pages[i]);
2165                         do {
2166                                 if (buffer_dirty(bh))
2167                                         nilfs_btree_add_dirty_buffer(btree,
2168                                                                      lists, bh);
2169                         } while ((bh = bh->b_this_page) != head);
2170                 }
2171                 pagevec_release(&pvec);
2172                 cond_resched();
2173         }
2174
2175         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
2176              level < NILFS_BTREE_LEVEL_MAX;
2177              level++)
2178                 list_splice_tail(&lists[level], listp);
2179 }
2180
2181 static int nilfs_btree_assign_p(struct nilfs_bmap *btree,
2182                                 struct nilfs_btree_path *path,
2183                                 int level,
2184                                 struct buffer_head **bh,
2185                                 sector_t blocknr,
2186                                 union nilfs_binfo *binfo)
2187 {
2188         struct nilfs_btree_node *parent;
2189         __u64 key;
2190         __u64 ptr;
2191         int ncmax, ret;
2192
2193         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2194         ptr = nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
2195                                        ncmax);
2196         if (buffer_nilfs_node(*bh)) {
2197                 path[level].bp_ctxt.oldkey = ptr;
2198                 path[level].bp_ctxt.newkey = blocknr;
2199                 path[level].bp_ctxt.bh = *bh;
2200                 ret = nilfs_btnode_prepare_change_key(
2201                         &NILFS_BMAP_I(btree)->i_btnode_cache,
2202                         &path[level].bp_ctxt);
2203                 if (ret < 0)
2204                         return ret;
2205                 nilfs_btnode_commit_change_key(
2206                         &NILFS_BMAP_I(btree)->i_btnode_cache,
2207                         &path[level].bp_ctxt);
2208                 *bh = path[level].bp_ctxt.bh;
2209         }
2210
2211         nilfs_btree_node_set_ptr(parent, path[level + 1].bp_index, blocknr,
2212                                  ncmax);
2213
2214         key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
2215         /* on-disk format */
2216         binfo->bi_dat.bi_blkoff = cpu_to_le64(key);
2217         binfo->bi_dat.bi_level = level;
2218
2219         return 0;
2220 }
2221
2222 static int nilfs_btree_assign_v(struct nilfs_bmap *btree,
2223                                 struct nilfs_btree_path *path,
2224                                 int level,
2225                                 struct buffer_head **bh,
2226                                 sector_t blocknr,
2227                                 union nilfs_binfo *binfo)
2228 {
2229         struct nilfs_btree_node *parent;
2230         struct inode *dat = nilfs_bmap_get_dat(btree);
2231         __u64 key;
2232         __u64 ptr;
2233         union nilfs_bmap_ptr_req req;
2234         int ncmax, ret;
2235
2236         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2237         ptr = nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
2238                                        ncmax);
2239         req.bpr_ptr = ptr;
2240         ret = nilfs_dat_prepare_start(dat, &req.bpr_req);
2241         if (ret < 0)
2242                 return ret;
2243         nilfs_dat_commit_start(dat, &req.bpr_req, blocknr);
2244
2245         key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
2246         /* on-disk format */
2247         binfo->bi_v.bi_vblocknr = cpu_to_le64(ptr);
2248         binfo->bi_v.bi_blkoff = cpu_to_le64(key);
2249
2250         return 0;
2251 }
2252
2253 static int nilfs_btree_assign(struct nilfs_bmap *btree,
2254                               struct buffer_head **bh,
2255                               sector_t blocknr,
2256                               union nilfs_binfo *binfo)
2257 {
2258         struct nilfs_btree_path *path;
2259         struct nilfs_btree_node *node;
2260         __u64 key;
2261         int level, ret;
2262
2263         path = nilfs_btree_alloc_path();
2264         if (path == NULL)
2265                 return -ENOMEM;
2266
2267         if (buffer_nilfs_node(*bh)) {
2268                 node = (struct nilfs_btree_node *)(*bh)->b_data;
2269                 key = nilfs_btree_node_get_key(node, 0);
2270                 level = nilfs_btree_node_get_level(node);
2271         } else {
2272                 key = nilfs_bmap_data_get_key(btree, *bh);
2273                 level = NILFS_BTREE_LEVEL_DATA;
2274         }
2275
2276         ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
2277         if (ret < 0) {
2278                 WARN_ON(ret == -ENOENT);
2279                 goto out;
2280         }
2281
2282         ret = NILFS_BMAP_USE_VBN(btree) ?
2283                 nilfs_btree_assign_v(btree, path, level, bh, blocknr, binfo) :
2284                 nilfs_btree_assign_p(btree, path, level, bh, blocknr, binfo);
2285
2286  out:
2287         nilfs_btree_free_path(path);
2288
2289         return ret;
2290 }
2291
2292 static int nilfs_btree_assign_gc(struct nilfs_bmap *btree,
2293                                  struct buffer_head **bh,
2294                                  sector_t blocknr,
2295                                  union nilfs_binfo *binfo)
2296 {
2297         struct nilfs_btree_node *node;
2298         __u64 key;
2299         int ret;
2300
2301         ret = nilfs_dat_move(nilfs_bmap_get_dat(btree), (*bh)->b_blocknr,
2302                              blocknr);
2303         if (ret < 0)
2304                 return ret;
2305
2306         if (buffer_nilfs_node(*bh)) {
2307                 node = (struct nilfs_btree_node *)(*bh)->b_data;
2308                 key = nilfs_btree_node_get_key(node, 0);
2309         } else
2310                 key = nilfs_bmap_data_get_key(btree, *bh);
2311
2312         /* on-disk format */
2313         binfo->bi_v.bi_vblocknr = cpu_to_le64((*bh)->b_blocknr);
2314         binfo->bi_v.bi_blkoff = cpu_to_le64(key);
2315
2316         return 0;
2317 }
2318
2319 static int nilfs_btree_mark(struct nilfs_bmap *btree, __u64 key, int level)
2320 {
2321         struct buffer_head *bh;
2322         struct nilfs_btree_path *path;
2323         __u64 ptr;
2324         int ret;
2325
2326         path = nilfs_btree_alloc_path();
2327         if (path == NULL)
2328                 return -ENOMEM;
2329
2330         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1, 0);
2331         if (ret < 0) {
2332                 WARN_ON(ret == -ENOENT);
2333                 goto out;
2334         }
2335         ret = nilfs_btree_get_block(btree, ptr, &bh);
2336         if (ret < 0) {
2337                 WARN_ON(ret == -ENOENT);
2338                 goto out;
2339         }
2340
2341         if (!buffer_dirty(bh))
2342                 mark_buffer_dirty(bh);
2343         brelse(bh);
2344         if (!nilfs_bmap_dirty(btree))
2345                 nilfs_bmap_set_dirty(btree);
2346
2347  out:
2348         nilfs_btree_free_path(path);
2349         return ret;
2350 }
2351
2352 static const struct nilfs_bmap_operations nilfs_btree_ops = {
2353         .bop_lookup             =       nilfs_btree_lookup,
2354         .bop_lookup_contig      =       nilfs_btree_lookup_contig,
2355         .bop_insert             =       nilfs_btree_insert,
2356         .bop_delete             =       nilfs_btree_delete,
2357         .bop_clear              =       NULL,
2358
2359         .bop_propagate          =       nilfs_btree_propagate,
2360
2361         .bop_lookup_dirty_buffers =     nilfs_btree_lookup_dirty_buffers,
2362
2363         .bop_assign             =       nilfs_btree_assign,
2364         .bop_mark               =       nilfs_btree_mark,
2365
2366         .bop_seek_key           =       nilfs_btree_seek_key,
2367         .bop_last_key           =       nilfs_btree_last_key,
2368
2369         .bop_check_insert       =       NULL,
2370         .bop_check_delete       =       nilfs_btree_check_delete,
2371         .bop_gather_data        =       nilfs_btree_gather_data,
2372 };
2373
2374 static const struct nilfs_bmap_operations nilfs_btree_ops_gc = {
2375         .bop_lookup             =       NULL,
2376         .bop_lookup_contig      =       NULL,
2377         .bop_insert             =       NULL,
2378         .bop_delete             =       NULL,
2379         .bop_clear              =       NULL,
2380
2381         .bop_propagate          =       nilfs_btree_propagate_gc,
2382
2383         .bop_lookup_dirty_buffers =     nilfs_btree_lookup_dirty_buffers,
2384
2385         .bop_assign             =       nilfs_btree_assign_gc,
2386         .bop_mark               =       NULL,
2387
2388         .bop_seek_key           =       NULL,
2389         .bop_last_key           =       NULL,
2390
2391         .bop_check_insert       =       NULL,
2392         .bop_check_delete       =       NULL,
2393         .bop_gather_data        =       NULL,
2394 };
2395
2396 static void __nilfs_btree_init(struct nilfs_bmap *bmap)
2397 {
2398         bmap->b_ops = &nilfs_btree_ops;
2399         bmap->b_nchildren_per_block =
2400                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
2401 }
2402
2403 int nilfs_btree_init(struct nilfs_bmap *bmap)
2404 {
2405         int ret = 0;
2406
2407         __nilfs_btree_init(bmap);
2408
2409         if (nilfs_btree_root_broken(nilfs_btree_get_root(bmap), bmap->b_inode))
2410                 ret = -EIO;
2411         return ret;
2412 }
2413
2414 void nilfs_btree_init_gc(struct nilfs_bmap *bmap)
2415 {
2416         bmap->b_ops = &nilfs_btree_ops_gc;
2417         bmap->b_nchildren_per_block =
2418                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
2419 }