fs/nilfs2/btree.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * btree.c - NILFS B-tree.
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Written by Koji Sato.
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/string.h>
  12 #include <linux/errno.h>
  13 #include <linux/pagevec.h>
  14 #include "nilfs.h"
  15 #include "page.h"
  16 #include "btnode.h"
  17 #include "btree.h"
  18 #include "alloc.h"
  19 #include "dat.h"
  20
  21 static void __nilfs_btree_init(struct nilfs_bmap *bmap);
  22
  23 static struct nilfs_btree_path *nilfs_btree_alloc_path(void)
  24 {
  25         struct nilfs_btree_path *path;
  26         int level = NILFS_BTREE_LEVEL_DATA;
  27
  28         path = kmem_cache_alloc(nilfs_btree_path_cache, GFP_NOFS);
  29         if (path == NULL)
  30                 goto out;
  31
  32         for (; level < NILFS_BTREE_LEVEL_MAX; level++) {
  33                 path[level].bp_bh = NULL;
  34                 path[level].bp_sib_bh = NULL;
  35                 path[level].bp_index = 0;
  36                 path[level].bp_oldreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
  37                 path[level].bp_newreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
  38                 path[level].bp_op = NULL;
  39         }
  40
  41 out:
  42         return path;
  43 }
  44
  45 static void nilfs_btree_free_path(struct nilfs_btree_path *path)
  46 {
  47         int level = NILFS_BTREE_LEVEL_DATA;
  48
  49         for (; level < NILFS_BTREE_LEVEL_MAX; level++)
  50                 brelse(path[level].bp_bh);
  51
  52         kmem_cache_free(nilfs_btree_path_cache, path);
  53 }
  54
  55 /*
  56  * B-tree node operations
  57  */
  58 static int nilfs_btree_get_new_block(const struct nilfs_bmap *btree,
  59                                      __u64 ptr, struct buffer_head **bhp)
  60 {
  61         struct inode *btnc_inode = NILFS_BMAP_I(btree)->i_assoc_inode;
  62         struct address_space *btnc = btnc_inode->i_mapping;
  63         struct buffer_head *bh;
  64
  65         bh = nilfs_btnode_create_block(btnc, ptr);
  66         if (!bh)
  67                 return -ENOMEM;
  68
  69         set_buffer_nilfs_volatile(bh);
  70         *bhp = bh;
  71         return 0;
  72 }
  73
  74 static int nilfs_btree_node_get_flags(const struct nilfs_btree_node *node)
  75 {
  76         return node->bn_flags;
  77 }
  78
  79 static void
  80 nilfs_btree_node_set_flags(struct nilfs_btree_node *node, int flags)
  81 {
  82         node->bn_flags = flags;
  83 }
  84
  85 static int nilfs_btree_node_root(const struct nilfs_btree_node *node)
  86 {
  87         return nilfs_btree_node_get_flags(node) & NILFS_BTREE_NODE_ROOT;
  88 }
  89
  90 static int nilfs_btree_node_get_level(const struct nilfs_btree_node *node)
  91 {
  92         return node->bn_level;
  93 }
  94
  95 static void
  96 nilfs_btree_node_set_level(struct nilfs_btree_node *node, int level)
  97 {
  98         node->bn_level = level;
  99 }
 100
 101 static int nilfs_btree_node_get_nchildren(const struct nilfs_btree_node *node)
 102 {
 103         return le16_to_cpu(node->bn_nchildren);
 104 }
 105
 106 static void
 107 nilfs_btree_node_set_nchildren(struct nilfs_btree_node *node, int nchildren)
 108 {
 109         node->bn_nchildren = cpu_to_le16(nchildren);
 110 }
 111
 112 static int nilfs_btree_node_size(const struct nilfs_bmap *btree)
 113 {
 114         return i_blocksize(btree->b_inode);
 115 }
 116
 117 static int nilfs_btree_nchildren_per_block(const struct nilfs_bmap *btree)
 118 {
 119         return btree->b_nchildren_per_block;
 120 }
 121
 122 static __le64 *
 123 nilfs_btree_node_dkeys(const struct nilfs_btree_node *node)
 124 {
 125         return (__le64 *)((char *)(node + 1) +
 126                           (nilfs_btree_node_root(node) ?
 127                            0 : NILFS_BTREE_NODE_EXTRA_PAD_SIZE));
 128 }
 129
 130 static __le64 *
 131 nilfs_btree_node_dptrs(const struct nilfs_btree_node *node, int ncmax)
 132 {
 133         return (__le64 *)(nilfs_btree_node_dkeys(node) + ncmax);
 134 }
 135
 136 static __u64
 137 nilfs_btree_node_get_key(const struct nilfs_btree_node *node, int index)
 138 {
 139         return le64_to_cpu(*(nilfs_btree_node_dkeys(node) + index));
 140 }
 141
 142 static void
 143 nilfs_btree_node_set_key(struct nilfs_btree_node *node, int index, __u64 key)
 144 {
 145         *(nilfs_btree_node_dkeys(node) + index) = cpu_to_le64(key);
 146 }
 147
 148 static __u64
 149 nilfs_btree_node_get_ptr(const struct nilfs_btree_node *node, int index,
 150                          int ncmax)
 151 {
 152         return le64_to_cpu(*(nilfs_btree_node_dptrs(node, ncmax) + index));
 153 }
 154
 155 static void
 156 nilfs_btree_node_set_ptr(struct nilfs_btree_node *node, int index, __u64 ptr,
 157                          int ncmax)
 158 {
 159         *(nilfs_btree_node_dptrs(node, ncmax) + index) = cpu_to_le64(ptr);
 160 }
 161
 162 static void nilfs_btree_node_init(struct nilfs_btree_node *node, int flags,
 163                                   int level, int nchildren, int ncmax,
 164                                   const __u64 *keys, const __u64 *ptrs)
 165 {
 166         __le64 *dkeys;
 167         __le64 *dptrs;
 168         int i;
 169
 170         nilfs_btree_node_set_flags(node, flags);
 171         nilfs_btree_node_set_level(node, level);
 172         nilfs_btree_node_set_nchildren(node, nchildren);
 173
 174         dkeys = nilfs_btree_node_dkeys(node);
 175         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 176         for (i = 0; i < nchildren; i++) {
 177                 dkeys[i] = cpu_to_le64(keys[i]);
 178                 dptrs[i] = cpu_to_le64(ptrs[i]);
 179         }
 180 }
 181
 182 /* Assume the buffer heads corresponding to left and right are locked. */
 183 static void nilfs_btree_node_move_left(struct nilfs_btree_node *left,
 184                                        struct nilfs_btree_node *right,
 185                                        int n, int lncmax, int rncmax)
 186 {
 187         __le64 *ldkeys, *rdkeys;
 188         __le64 *ldptrs, *rdptrs;
 189         int lnchildren, rnchildren;
 190
 191         ldkeys = nilfs_btree_node_dkeys(left);
 192         ldptrs = nilfs_btree_node_dptrs(left, lncmax);
 193         lnchildren = nilfs_btree_node_get_nchildren(left);
 194
 195         rdkeys = nilfs_btree_node_dkeys(right);
 196         rdptrs = nilfs_btree_node_dptrs(right, rncmax);
 197         rnchildren = nilfs_btree_node_get_nchildren(right);
 198
 199         memcpy(ldkeys + lnchildren, rdkeys, n * sizeof(*rdkeys));
 200         memcpy(ldptrs + lnchildren, rdptrs, n * sizeof(*rdptrs));
 201         memmove(rdkeys, rdkeys + n, (rnchildren - n) * sizeof(*rdkeys));
 202         memmove(rdptrs, rdptrs + n, (rnchildren - n) * sizeof(*rdptrs));
 203
 204         lnchildren += n;
 205         rnchildren -= n;
 206         nilfs_btree_node_set_nchildren(left, lnchildren);
 207         nilfs_btree_node_set_nchildren(right, rnchildren);
 208 }
 209
 210 /* Assume that the buffer heads corresponding to left and right are locked. */
 211 static void nilfs_btree_node_move_right(struct nilfs_btree_node *left,
 212                                         struct nilfs_btree_node *right,
 213                                         int n, int lncmax, int rncmax)
 214 {
 215         __le64 *ldkeys, *rdkeys;
 216         __le64 *ldptrs, *rdptrs;
 217         int lnchildren, rnchildren;
 218
 219         ldkeys = nilfs_btree_node_dkeys(left);
 220         ldptrs = nilfs_btree_node_dptrs(left, lncmax);
 221         lnchildren = nilfs_btree_node_get_nchildren(left);
 222
 223         rdkeys = nilfs_btree_node_dkeys(right);
 224         rdptrs = nilfs_btree_node_dptrs(right, rncmax);
 225         rnchildren = nilfs_btree_node_get_nchildren(right);
 226
 227         memmove(rdkeys + n, rdkeys, rnchildren * sizeof(*rdkeys));
 228         memmove(rdptrs + n, rdptrs, rnchildren * sizeof(*rdptrs));
 229         memcpy(rdkeys, ldkeys + lnchildren - n, n * sizeof(*rdkeys));
 230         memcpy(rdptrs, ldptrs + lnchildren - n, n * sizeof(*rdptrs));
 231
 232         lnchildren -= n;
 233         rnchildren += n;
 234         nilfs_btree_node_set_nchildren(left, lnchildren);
 235         nilfs_btree_node_set_nchildren(right, rnchildren);
 236 }
 237
 238 /* Assume that the buffer head corresponding to node is locked. */
 239 static void nilfs_btree_node_insert(struct nilfs_btree_node *node, int index,
 240                                     __u64 key, __u64 ptr, int ncmax)
 241 {
 242         __le64 *dkeys;
 243         __le64 *dptrs;
 244         int nchildren;
 245
 246         dkeys = nilfs_btree_node_dkeys(node);
 247         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 248         nchildren = nilfs_btree_node_get_nchildren(node);
 249         if (index < nchildren) {
 250                 memmove(dkeys + index + 1, dkeys + index,
 251                         (nchildren - index) * sizeof(*dkeys));
 252                 memmove(dptrs + index + 1, dptrs + index,
 253                         (nchildren - index) * sizeof(*dptrs));
 254         }
 255         dkeys[index] = cpu_to_le64(key);
 256         dptrs[index] = cpu_to_le64(ptr);
 257         nchildren++;
 258         nilfs_btree_node_set_nchildren(node, nchildren);
 259 }
 260
 261 /* Assume that the buffer head corresponding to node is locked. */
 262 static void nilfs_btree_node_delete(struct nilfs_btree_node *node, int index,
 263                                     __u64 *keyp, __u64 *ptrp, int ncmax)
 264 {
 265         __u64 key;
 266         __u64 ptr;
 267         __le64 *dkeys;
 268         __le64 *dptrs;
 269         int nchildren;
 270
 271         dkeys = nilfs_btree_node_dkeys(node);
 272         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 273         key = le64_to_cpu(dkeys[index]);
 274         ptr = le64_to_cpu(dptrs[index]);
 275         nchildren = nilfs_btree_node_get_nchildren(node);
 276         if (keyp != NULL)
 277                 *keyp = key;
 278         if (ptrp != NULL)
 279                 *ptrp = ptr;
 280
 281         if (index < nchildren - 1) {
 282                 memmove(dkeys + index, dkeys + index + 1,
 283                         (nchildren - index - 1) * sizeof(*dkeys));
 284                 memmove(dptrs + index, dptrs + index + 1,
 285                         (nchildren - index - 1) * sizeof(*dptrs));
 286         }
 287         nchildren--;
 288         nilfs_btree_node_set_nchildren(node, nchildren);
 289 }
 290
 291 static int nilfs_btree_node_lookup(const struct nilfs_btree_node *node,
 292                                    __u64 key, int *indexp)
 293 {
 294         __u64 nkey;
 295         int index, low, high, s;
 296
 297         /* binary search */
 298         low = 0;
 299         high = nilfs_btree_node_get_nchildren(node) - 1;
 300         index = 0;
 301         s = 0;
 302         while (low <= high) {
 303                 index = (low + high) / 2;
 304                 nkey = nilfs_btree_node_get_key(node, index);
 305                 if (nkey == key) {
 306                         s = 0;
 307                         goto out;
 308                 } else if (nkey < key) {
 309                         low = index + 1;
 310                         s = -1;
 311                 } else {
 312                         high = index - 1;
 313                         s = 1;
 314                 }
 315         }
 316
 317         /* adjust index */
 318         if (nilfs_btree_node_get_level(node) > NILFS_BTREE_LEVEL_NODE_MIN) {
 319                 if (s > 0 && index > 0)
 320                         index--;
 321         } else if (s < 0)
 322                 index++;
 323
 324  out:
 325         *indexp = index;
 326
 327         return s == 0;
 328 }
 329
 330 /**
 331  * nilfs_btree_node_broken - verify consistency of btree node
 332  * @node: btree node block to be examined
 333  * @size: node size (in bytes)
 334  * @inode: host inode of btree
 335  * @blocknr: block number
 336  *
 337  * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
 338  */
 339 static int nilfs_btree_node_broken(const struct nilfs_btree_node *node,
 340                                    size_t size, struct inode *inode,
 341                                    sector_t blocknr)
 342 {
 343         int level, flags, nchildren;
 344         int ret = 0;
 345
 346         level = nilfs_btree_node_get_level(node);
 347         flags = nilfs_btree_node_get_flags(node);
 348         nchildren = nilfs_btree_node_get_nchildren(node);
 349
 350         if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
 351                      level >= NILFS_BTREE_LEVEL_MAX ||
 352                      (flags & NILFS_BTREE_NODE_ROOT) ||
 353                      nchildren < 0 ||
 354                      nchildren > NILFS_BTREE_NODE_NCHILDREN_MAX(size))) {
 355                 nilfs_msg(inode->i_sb, KERN_CRIT,
 356                           "bad btree node (ino=%lu, blocknr=%llu): level = %d, flags = 0x%x, nchildren = %d",
 357                           inode->i_ino, (unsigned long long)blocknr, level,
 358                           flags, nchildren);
 359                 ret = 1;
 360         }
 361         return ret;
 362 }
 363
 364 /**
 365  * nilfs_btree_root_broken - verify consistency of btree root node
 366  * @node: btree root node to be examined
 367  * @inode: host inode of btree
 368  *
 369  * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
 370  */
 371 static int nilfs_btree_root_broken(const struct nilfs_btree_node *node,
 372                                    struct inode *inode)
 373 {
 374         int level, flags, nchildren;
 375         int ret = 0;
 376
 377         level = nilfs_btree_node_get_level(node);
 378         flags = nilfs_btree_node_get_flags(node);
 379         nchildren = nilfs_btree_node_get_nchildren(node);
 380
 381         if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
 382                      level >= NILFS_BTREE_LEVEL_MAX ||
 383                      nchildren < 0 ||
 384                      nchildren > NILFS_BTREE_ROOT_NCHILDREN_MAX)) {
 385                 nilfs_msg(inode->i_sb, KERN_CRIT,
 386                           "bad btree root (ino=%lu): level = %d, flags = 0x%x, nchildren = %d",
 387                           inode->i_ino, level, flags, nchildren);
 388                 ret = 1;
 389         }
 390         return ret;
 391 }
 392
 393 int nilfs_btree_broken_node_block(struct buffer_head *bh)
 394 {
 395         struct inode *inode;
 396         int ret;
 397
 398         if (buffer_nilfs_checked(bh))
 399                 return 0;
 400
 401         inode = bh->b_page->mapping->host;
 402         ret = nilfs_btree_node_broken((struct nilfs_btree_node *)bh->b_data,
 403                                       bh->b_size, inode, bh->b_blocknr);
 404         if (likely(!ret))
 405                 set_buffer_nilfs_checked(bh);
 406         return ret;
 407 }
 408
 409 static struct nilfs_btree_node *
 410 nilfs_btree_get_root(const struct nilfs_bmap *btree)
 411 {
 412         return (struct nilfs_btree_node *)btree->b_u.u_data;
 413 }
 414
 415 static struct nilfs_btree_node *
 416 nilfs_btree_get_nonroot_node(const struct nilfs_btree_path *path, int level)
 417 {
 418         return (struct nilfs_btree_node *)path[level].bp_bh->b_data;
 419 }
 420
 421 static struct nilfs_btree_node *
 422 nilfs_btree_get_sib_node(const struct nilfs_btree_path *path, int level)
 423 {
 424         return (struct nilfs_btree_node *)path[level].bp_sib_bh->b_data;
 425 }
 426
 427 static int nilfs_btree_height(const struct nilfs_bmap *btree)
 428 {
 429         return nilfs_btree_node_get_level(nilfs_btree_get_root(btree)) + 1;
 430 }
 431
 432 static struct nilfs_btree_node *
 433 nilfs_btree_get_node(const struct nilfs_bmap *btree,
 434                      const struct nilfs_btree_path *path,
 435                      int level, int *ncmaxp)
 436 {
 437         struct nilfs_btree_node *node;
 438
 439         if (level == nilfs_btree_height(btree) - 1) {
 440                 node = nilfs_btree_get_root(btree);
 441                 *ncmaxp = NILFS_BTREE_ROOT_NCHILDREN_MAX;
 442         } else {
 443                 node = nilfs_btree_get_nonroot_node(path, level);
 444                 *ncmaxp = nilfs_btree_nchildren_per_block(btree);
 445         }
 446         return node;
 447 }
 448
 449 static int nilfs_btree_bad_node(const struct nilfs_bmap *btree,
 450                                 struct nilfs_btree_node *node, int level)
 451 {
 452         if (unlikely(nilfs_btree_node_get_level(node) != level)) {
 453                 dump_stack();
 454                 nilfs_msg(btree->b_inode->i_sb, KERN_CRIT,
 455                           "btree level mismatch (ino=%lu): %d != %d",
 456                           btree->b_inode->i_ino,
 457                           nilfs_btree_node_get_level(node), level);
 458                 return 1;
 459         }
 460         return 0;
 461 }
 462
 463 struct nilfs_btree_readahead_info {
 464         struct nilfs_btree_node *node;  /* parent node */
 465         int max_ra_blocks;              /* max nof blocks to read ahead */
 466         int index;                      /* current index on the parent node */
 467         int ncmax;                      /* nof children in the parent node */
 468 };
 469
 470 static int __nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
 471                                    struct buffer_head **bhp,
 472                                    const struct nilfs_btree_readahead_info *ra)
 473 {
 474         struct inode *btnc_inode = NILFS_BMAP_I(btree)->i_assoc_inode;
 475         struct address_space *btnc = btnc_inode->i_mapping;
 476         struct buffer_head *bh, *ra_bh;
 477         sector_t submit_ptr = 0;
 478         int ret;
 479
 480         ret = nilfs_btnode_submit_block(btnc, ptr, 0, REQ_OP_READ, 0, &bh,
 481                                         &submit_ptr);
 482         if (ret) {
 483                 if (likely(ret == -EEXIST))
 484                         goto out_check;
 485                 if (ret == -ENOENT) {
 486                         /*
 487                          * Block address translation failed due to invalid
 488                          * value of 'ptr'.  In this case, return internal code
 489                          * -EINVAL (broken bmap) to notify bmap layer of fatal
 490                          * metadata corruption.
 491                          */
 492                         ret = -EINVAL;
 493                 }
 494                 return ret;
 495         }
 496
 497         if (ra) {
 498                 int i, n;
 499                 __u64 ptr2;
 500
 501                 /* read ahead sibling nodes */
 502                 for (n = ra->max_ra_blocks, i = ra->index + 1;
 503                      n > 0 && i < ra->ncmax; n--, i++) {
 504                         ptr2 = nilfs_btree_node_get_ptr(ra->node, i, ra->ncmax);
 505
 506                         ret = nilfs_btnode_submit_block(btnc, ptr2, 0,
 507                                                         REQ_OP_READ, REQ_RAHEAD,
 508                                                         &ra_bh, &submit_ptr);
 509                         if (likely(!ret || ret == -EEXIST))
 510                                 brelse(ra_bh);
 511                         else if (ret != -EBUSY)
 512                                 break;
 513                         if (!buffer_locked(bh))
 514                                 goto out_no_wait;
 515                 }
 516         }
 517
 518         wait_on_buffer(bh);
 519
 520  out_no_wait:
 521         if (!buffer_uptodate(bh)) {
 522                 nilfs_msg(btree->b_inode->i_sb, KERN_ERR,
 523                           "I/O error reading b-tree node block (ino=%lu, blocknr=%llu)",
 524                           btree->b_inode->i_ino, (unsigned long long)ptr);
 525                 brelse(bh);
 526                 return -EIO;
 527         }
 528
 529  out_check:
 530         if (nilfs_btree_broken_node_block(bh)) {
 531                 clear_buffer_uptodate(bh);
 532                 brelse(bh);
 533                 return -EINVAL;
 534         }
 535
 536         *bhp = bh;
 537         return 0;
 538 }
 539
 540 static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
 541                                    struct buffer_head **bhp)
 542 {
 543         return __nilfs_btree_get_block(btree, ptr, bhp, NULL);
 544 }
 545
 546 static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree,
 547                                  struct nilfs_btree_path *path,
 548                                  __u64 key, __u64 *ptrp, int minlevel,
 549                                  int readahead)
 550 {
 551         struct nilfs_btree_node *node;
 552         struct nilfs_btree_readahead_info p, *ra;
 553         __u64 ptr;
 554         int level, index, found, ncmax, ret;
 555
 556         node = nilfs_btree_get_root(btree);
 557         level = nilfs_btree_node_get_level(node);
 558         if (level < minlevel || nilfs_btree_node_get_nchildren(node) <= 0)
 559                 return -ENOENT;
 560
 561         found = nilfs_btree_node_lookup(node, key, &index);
 562         ptr = nilfs_btree_node_get_ptr(node, index,
 563                                        NILFS_BTREE_ROOT_NCHILDREN_MAX);
 564         path[level].bp_bh = NULL;
 565         path[level].bp_index = index;
 566
 567         ncmax = nilfs_btree_nchildren_per_block(btree);
 568
 569         while (--level >= minlevel) {
 570                 ra = NULL;
 571                 if (level == NILFS_BTREE_LEVEL_NODE_MIN && readahead) {
 572                         p.node = nilfs_btree_get_node(btree, path, level + 1,
 573                                                       &p.ncmax);
 574                         p.index = index;
 575                         p.max_ra_blocks = 7;
 576                         ra = &p;
 577                 }
 578                 ret = __nilfs_btree_get_block(btree, ptr, &path[level].bp_bh,
 579                                               ra);
 580                 if (ret < 0)
 581                         return ret;
 582
 583                 node = nilfs_btree_get_nonroot_node(path, level);
 584                 if (nilfs_btree_bad_node(btree, node, level))
 585                         return -EINVAL;
 586                 if (!found)
 587                         found = nilfs_btree_node_lookup(node, key, &index);
 588                 else
 589                         index = 0;
 590                 if (index < ncmax) {
 591                         ptr = nilfs_btree_node_get_ptr(node, index, ncmax);
 592                 } else {
 593                         WARN_ON(found || level != NILFS_BTREE_LEVEL_NODE_MIN);
 594                         /* insert */
 595                         ptr = NILFS_BMAP_INVALID_PTR;
 596                 }
 597                 path[level].bp_index = index;
 598         }
 599         if (!found)
 600                 return -ENOENT;
 601
 602         if (ptrp != NULL)
 603                 *ptrp = ptr;
 604
 605         return 0;
 606 }
 607
 608 static int nilfs_btree_do_lookup_last(const struct nilfs_bmap *btree,
 609                                       struct nilfs_btree_path *path,
 610                                       __u64 *keyp, __u64 *ptrp)
 611 {
 612         struct nilfs_btree_node *node;
 613         __u64 ptr;
 614         int index, level, ncmax, ret;
 615
 616         node = nilfs_btree_get_root(btree);
 617         index = nilfs_btree_node_get_nchildren(node) - 1;
 618         if (index < 0)
 619                 return -ENOENT;
 620         level = nilfs_btree_node_get_level(node);
 621         ptr = nilfs_btree_node_get_ptr(node, index,
 622                                        NILFS_BTREE_ROOT_NCHILDREN_MAX);
 623         path[level].bp_bh = NULL;
 624         path[level].bp_index = index;
 625         ncmax = nilfs_btree_nchildren_per_block(btree);
 626
 627         for (level--; level > 0; level--) {
 628                 ret = nilfs_btree_get_block(btree, ptr, &path[level].bp_bh);
 629                 if (ret < 0)
 630                         return ret;
 631                 node = nilfs_btree_get_nonroot_node(path, level);
 632                 if (nilfs_btree_bad_node(btree, node, level))
 633                         return -EINVAL;
 634                 index = nilfs_btree_node_get_nchildren(node) - 1;
 635                 ptr = nilfs_btree_node_get_ptr(node, index, ncmax);
 636                 path[level].bp_index = index;
 637         }
 638
 639         if (keyp != NULL)
 640                 *keyp = nilfs_btree_node_get_key(node, index);
 641         if (ptrp != NULL)
 642                 *ptrp = ptr;
 643
 644         return 0;
 645 }
 646
 647 /**
 648  * nilfs_btree_get_next_key - get next valid key from btree path array
 649  * @btree: bmap struct of btree
 650  * @path: array of nilfs_btree_path struct
 651  * @minlevel: start level
 652  * @nextkey: place to store the next valid key
 653  *
 654  * Return Value: If a next key was found, 0 is returned. Otherwise,
 655  * -ENOENT is returned.
 656  */
 657 static int nilfs_btree_get_next_key(const struct nilfs_bmap *btree,
 658                                     const struct nilfs_btree_path *path,
 659                                     int minlevel, __u64 *nextkey)
 660 {
 661         struct nilfs_btree_node *node;
 662         int maxlevel = nilfs_btree_height(btree) - 1;
 663         int index, next_adj, level;
 664
 665         /* Next index is already set to bp_index for leaf nodes. */
 666         next_adj = 0;
 667         for (level = minlevel; level <= maxlevel; level++) {
 668                 if (level == maxlevel)
 669                         node = nilfs_btree_get_root(btree);
 670                 else
 671                         node = nilfs_btree_get_nonroot_node(path, level);
 672
 673                 index = path[level].bp_index + next_adj;
 674                 if (index < nilfs_btree_node_get_nchildren(node)) {
 675                         /* Next key is in this node */
 676                         *nextkey = nilfs_btree_node_get_key(node, index);
 677                         return 0;
 678                 }
 679                 /* For non-leaf nodes, next index is stored at bp_index + 1. */
 680                 next_adj = 1;
 681         }
 682         return -ENOENT;
 683 }
 684
 685 static int nilfs_btree_lookup(const struct nilfs_bmap *btree,
 686                               __u64 key, int level, __u64 *ptrp)
 687 {
 688         struct nilfs_btree_path *path;
 689         int ret;
 690
 691         path = nilfs_btree_alloc_path();
 692         if (path == NULL)
 693                 return -ENOMEM;
 694
 695         ret = nilfs_btree_do_lookup(btree, path, key, ptrp, level, 0);
 696
 697         nilfs_btree_free_path(path);
 698
 699         return ret;
 700 }
 701
 702 static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree,
 703                                      __u64 key, __u64 *ptrp,
 704                                      unsigned int maxblocks)
 705 {
 706         struct nilfs_btree_path *path;
 707         struct nilfs_btree_node *node;
 708         struct inode *dat = NULL;
 709         __u64 ptr, ptr2;
 710         sector_t blocknr;
 711         int level = NILFS_BTREE_LEVEL_NODE_MIN;
 712         int ret, cnt, index, maxlevel, ncmax;
 713         struct nilfs_btree_readahead_info p;
 714
 715         path = nilfs_btree_alloc_path();
 716         if (path == NULL)
 717                 return -ENOMEM;
 718
 719         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level, 1);
 720         if (ret < 0)
 721                 goto out;
 722
 723         if (NILFS_BMAP_USE_VBN(btree)) {
 724                 dat = nilfs_bmap_get_dat(btree);
 725                 ret = nilfs_dat_translate(dat, ptr, &blocknr);
 726                 if (ret < 0)
 727                         goto out;
 728                 ptr = blocknr;
 729         }
 730         cnt = 1;
 731         if (cnt == maxblocks)
 732                 goto end;
 733
 734         maxlevel = nilfs_btree_height(btree) - 1;
 735         node = nilfs_btree_get_node(btree, path, level, &ncmax);
 736         index = path[level].bp_index + 1;
 737         for (;;) {
 738                 while (index < nilfs_btree_node_get_nchildren(node)) {
 739                         if (nilfs_btree_node_get_key(node, index) !=
 740                             key + cnt)
 741                                 goto end;
 742                         ptr2 = nilfs_btree_node_get_ptr(node, index, ncmax);
 743                         if (dat) {
 744                                 ret = nilfs_dat_translate(dat, ptr2, &blocknr);
 745                                 if (ret < 0)
 746                                         goto out;
 747                                 ptr2 = blocknr;
 748                         }
 749                         if (ptr2 != ptr + cnt || ++cnt == maxblocks)
 750                                 goto end;
 751                         index++;
 752                         continue;
 753                 }
 754                 if (level == maxlevel)
 755                         break;
 756
 757                 /* look-up right sibling node */
 758                 p.node = nilfs_btree_get_node(btree, path, level + 1, &p.ncmax);
 759                 p.index = path[level + 1].bp_index + 1;
 760                 p.max_ra_blocks = 7;
 761                 if (p.index >= nilfs_btree_node_get_nchildren(p.node) ||
 762                     nilfs_btree_node_get_key(p.node, p.index) != key + cnt)
 763                         break;
 764                 ptr2 = nilfs_btree_node_get_ptr(p.node, p.index, p.ncmax);
 765                 path[level + 1].bp_index = p.index;
 766
 767                 brelse(path[level].bp_bh);
 768                 path[level].bp_bh = NULL;
 769
 770                 ret = __nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh,
 771                                               &p);
 772                 if (ret < 0)
 773                         goto out;
 774                 node = nilfs_btree_get_nonroot_node(path, level);
 775                 ncmax = nilfs_btree_nchildren_per_block(btree);
 776                 index = 0;
 777                 path[level].bp_index = index;
 778         }
 779  end:
 780         *ptrp = ptr;
 781         ret = cnt;
 782  out:
 783         nilfs_btree_free_path(path);
 784         return ret;
 785 }
 786
 787 static void nilfs_btree_promote_key(struct nilfs_bmap *btree,
 788                                     struct nilfs_btree_path *path,
 789                                     int level, __u64 key)
 790 {
 791         if (level < nilfs_btree_height(btree) - 1) {
 792                 do {
 793                         nilfs_btree_node_set_key(
 794                                 nilfs_btree_get_nonroot_node(path, level),
 795                                 path[level].bp_index, key);
 796                         if (!buffer_dirty(path[level].bp_bh))
 797                                 mark_buffer_dirty(path[level].bp_bh);
 798                 } while ((path[level].bp_index == 0) &&
 799                          (++level < nilfs_btree_height(btree) - 1));
 800         }
 801
 802         /* root */
 803         if (level == nilfs_btree_height(btree) - 1) {
 804                 nilfs_btree_node_set_key(nilfs_btree_get_root(btree),
 805                                          path[level].bp_index, key);
 806         }
 807 }
 808
 809 static void nilfs_btree_do_insert(struct nilfs_bmap *btree,
 810                                   struct nilfs_btree_path *path,
 811                                   int level, __u64 *keyp, __u64 *ptrp)
 812 {
 813         struct nilfs_btree_node *node;
 814         int ncblk;
 815
 816         if (level < nilfs_btree_height(btree) - 1) {
 817                 node = nilfs_btree_get_nonroot_node(path, level);
 818                 ncblk = nilfs_btree_nchildren_per_block(btree);
 819                 nilfs_btree_node_insert(node, path[level].bp_index,
 820                                         *keyp, *ptrp, ncblk);
 821                 if (!buffer_dirty(path[level].bp_bh))
 822                         mark_buffer_dirty(path[level].bp_bh);
 823
 824                 if (path[level].bp_index == 0)
 825                         nilfs_btree_promote_key(btree, path, level + 1,
 826                                                 nilfs_btree_node_get_key(node,
 827                                                                          0));
 828         } else {
 829                 node = nilfs_btree_get_root(btree);
 830                 nilfs_btree_node_insert(node, path[level].bp_index,
 831                                         *keyp, *ptrp,
 832                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
 833         }
 834 }
 835
 836 static void nilfs_btree_carry_left(struct nilfs_bmap *btree,
 837                                    struct nilfs_btree_path *path,
 838                                    int level, __u64 *keyp, __u64 *ptrp)
 839 {
 840         struct nilfs_btree_node *node, *left;
 841         int nchildren, lnchildren, n, move, ncblk;
 842
 843         node = nilfs_btree_get_nonroot_node(path, level);
 844         left = nilfs_btree_get_sib_node(path, level);
 845         nchildren = nilfs_btree_node_get_nchildren(node);
 846         lnchildren = nilfs_btree_node_get_nchildren(left);
 847         ncblk = nilfs_btree_nchildren_per_block(btree);
 848         move = 0;
 849
 850         n = (nchildren + lnchildren + 1) / 2 - lnchildren;
 851         if (n > path[level].bp_index) {
 852                 /* move insert point */
 853                 n--;
 854                 move = 1;
 855         }
 856
 857         nilfs_btree_node_move_left(left, node, n, ncblk, ncblk);
 858
 859         if (!buffer_dirty(path[level].bp_bh))
 860                 mark_buffer_dirty(path[level].bp_bh);
 861         if (!buffer_dirty(path[level].bp_sib_bh))
 862                 mark_buffer_dirty(path[level].bp_sib_bh);
 863
 864         nilfs_btree_promote_key(btree, path, level + 1,
 865                                 nilfs_btree_node_get_key(node, 0));
 866
 867         if (move) {
 868                 brelse(path[level].bp_bh);
 869                 path[level].bp_bh = path[level].bp_sib_bh;
 870                 path[level].bp_sib_bh = NULL;
 871                 path[level].bp_index += lnchildren;
 872                 path[level + 1].bp_index--;
 873         } else {
 874                 brelse(path[level].bp_sib_bh);
 875                 path[level].bp_sib_bh = NULL;
 876                 path[level].bp_index -= n;
 877         }
 878
 879         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 880 }
 881
 882 static void nilfs_btree_carry_right(struct nilfs_bmap *btree,
 883                                     struct nilfs_btree_path *path,
 884                                     int level, __u64 *keyp, __u64 *ptrp)
 885 {
 886         struct nilfs_btree_node *node, *right;
 887         int nchildren, rnchildren, n, move, ncblk;
 888
 889         node = nilfs_btree_get_nonroot_node(path, level);
 890         right = nilfs_btree_get_sib_node(path, level);
 891         nchildren = nilfs_btree_node_get_nchildren(node);
 892         rnchildren = nilfs_btree_node_get_nchildren(right);
 893         ncblk = nilfs_btree_nchildren_per_block(btree);
 894         move = 0;
 895
 896         n = (nchildren + rnchildren + 1) / 2 - rnchildren;
 897         if (n > nchildren - path[level].bp_index) {
 898                 /* move insert point */
 899                 n--;
 900                 move = 1;
 901         }
 902
 903         nilfs_btree_node_move_right(node, right, n, ncblk, ncblk);
 904
 905         if (!buffer_dirty(path[level].bp_bh))
 906                 mark_buffer_dirty(path[level].bp_bh);
 907         if (!buffer_dirty(path[level].bp_sib_bh))
 908                 mark_buffer_dirty(path[level].bp_sib_bh);
 909
 910         path[level + 1].bp_index++;
 911         nilfs_btree_promote_key(btree, path, level + 1,
 912                                 nilfs_btree_node_get_key(right, 0));
 913         path[level + 1].bp_index--;
 914
 915         if (move) {
 916                 brelse(path[level].bp_bh);
 917                 path[level].bp_bh = path[level].bp_sib_bh;
 918                 path[level].bp_sib_bh = NULL;
 919                 path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
 920                 path[level + 1].bp_index++;
 921         } else {
 922                 brelse(path[level].bp_sib_bh);
 923                 path[level].bp_sib_bh = NULL;
 924         }
 925
 926         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 927 }
 928
 929 static void nilfs_btree_split(struct nilfs_bmap *btree,
 930                               struct nilfs_btree_path *path,
 931                               int level, __u64 *keyp, __u64 *ptrp)
 932 {
 933         struct nilfs_btree_node *node, *right;
 934         int nchildren, n, move, ncblk;
 935
 936         node = nilfs_btree_get_nonroot_node(path, level);
 937         right = nilfs_btree_get_sib_node(path, level);
 938         nchildren = nilfs_btree_node_get_nchildren(node);
 939         ncblk = nilfs_btree_nchildren_per_block(btree);
 940         move = 0;
 941
 942         n = (nchildren + 1) / 2;
 943         if (n > nchildren - path[level].bp_index) {
 944                 n--;
 945                 move = 1;
 946         }
 947
 948         nilfs_btree_node_move_right(node, right, n, ncblk, ncblk);
 949
 950         if (!buffer_dirty(path[level].bp_bh))
 951                 mark_buffer_dirty(path[level].bp_bh);
 952         if (!buffer_dirty(path[level].bp_sib_bh))
 953                 mark_buffer_dirty(path[level].bp_sib_bh);
 954
 955         if (move) {
 956                 path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
 957                 nilfs_btree_node_insert(right, path[level].bp_index,
 958                                         *keyp, *ptrp, ncblk);
 959
 960                 *keyp = nilfs_btree_node_get_key(right, 0);
 961                 *ptrp = path[level].bp_newreq.bpr_ptr;
 962
 963                 brelse(path[level].bp_bh);
 964                 path[level].bp_bh = path[level].bp_sib_bh;
 965                 path[level].bp_sib_bh = NULL;
 966         } else {
 967                 nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 968
 969                 *keyp = nilfs_btree_node_get_key(right, 0);
 970                 *ptrp = path[level].bp_newreq.bpr_ptr;
 971
 972                 brelse(path[level].bp_sib_bh);
 973                 path[level].bp_sib_bh = NULL;
 974         }
 975
 976         path[level + 1].bp_index++;
 977 }
 978
 979 static void nilfs_btree_grow(struct nilfs_bmap *btree,
 980                              struct nilfs_btree_path *path,
 981                              int level, __u64 *keyp, __u64 *ptrp)
 982 {
 983         struct nilfs_btree_node *root, *child;
 984         int n, ncblk;
 985
 986         root = nilfs_btree_get_root(btree);
 987         child = nilfs_btree_get_sib_node(path, level);
 988         ncblk = nilfs_btree_nchildren_per_block(btree);
 989
 990         n = nilfs_btree_node_get_nchildren(root);
 991
 992         nilfs_btree_node_move_right(root, child, n,
 993                                     NILFS_BTREE_ROOT_NCHILDREN_MAX, ncblk);
 994         nilfs_btree_node_set_level(root, level + 1);
 995
 996         if (!buffer_dirty(path[level].bp_sib_bh))
 997                 mark_buffer_dirty(path[level].bp_sib_bh);
 998
 999         path[level].bp_bh = path[level].bp_sib_bh;
1000         path[level].bp_sib_bh = NULL;
1001
1002         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
1003
1004         *keyp = nilfs_btree_node_get_key(child, 0);
1005         *ptrp = path[level].bp_newreq.bpr_ptr;
1006 }
1007
1008 static __u64 nilfs_btree_find_near(const struct nilfs_bmap *btree,
1009                                    const struct nilfs_btree_path *path)
1010 {
1011         struct nilfs_btree_node *node;
1012         int level, ncmax;
1013
1014         if (path == NULL)
1015                 return NILFS_BMAP_INVALID_PTR;
1016
1017         /* left sibling */
1018         level = NILFS_BTREE_LEVEL_NODE_MIN;
1019         if (path[level].bp_index > 0) {
1020                 node = nilfs_btree_get_node(btree, path, level, &ncmax);
1021                 return nilfs_btree_node_get_ptr(node,
1022                                                 path[level].bp_index - 1,
1023                                                 ncmax);
1024         }
1025
1026         /* parent */
1027         level = NILFS_BTREE_LEVEL_NODE_MIN + 1;
1028         if (level <= nilfs_btree_height(btree) - 1) {
1029                 node = nilfs_btree_get_node(btree, path, level, &ncmax);
1030                 return nilfs_btree_node_get_ptr(node, path[level].bp_index,
1031                                                 ncmax);
1032         }
1033
1034         return NILFS_BMAP_INVALID_PTR;
1035 }
1036
1037 static __u64 nilfs_btree_find_target_v(const struct nilfs_bmap *btree,
1038                                        const struct nilfs_btree_path *path,
1039                                        __u64 key)
1040 {
1041         __u64 ptr;
1042
1043         ptr = nilfs_bmap_find_target_seq(btree, key);
1044         if (ptr != NILFS_BMAP_INVALID_PTR)
1045                 /* sequential access */
1046                 return ptr;
1047
1048         ptr = nilfs_btree_find_near(btree, path);
1049         if (ptr != NILFS_BMAP_INVALID_PTR)
1050                 /* near */
1051                 return ptr;
1052
1053         /* block group */
1054         return nilfs_bmap_find_target_in_group(btree);
1055 }
1056
1057 static int nilfs_btree_prepare_insert(struct nilfs_bmap *btree,
1058                                       struct nilfs_btree_path *path,
1059                                       int *levelp, __u64 key, __u64 ptr,
1060                                       struct nilfs_bmap_stats *stats)
1061 {
1062         struct buffer_head *bh;
1063         struct nilfs_btree_node *node, *parent, *sib;
1064         __u64 sibptr;
1065         int pindex, level, ncmax, ncblk, ret;
1066         struct inode *dat = NULL;
1067
1068         stats->bs_nblocks = 0;
1069         level = NILFS_BTREE_LEVEL_DATA;
1070
1071         /* allocate a new ptr for data block */
1072         if (NILFS_BMAP_USE_VBN(btree)) {
1073                 path[level].bp_newreq.bpr_ptr =
1074                         nilfs_btree_find_target_v(btree, path, key);
1075                 dat = nilfs_bmap_get_dat(btree);
1076         }
1077
1078         ret = nilfs_bmap_prepare_alloc_ptr(btree, &path[level].bp_newreq, dat);
1079         if (ret < 0)
1080                 goto err_out_data;
1081
1082         ncblk = nilfs_btree_nchildren_per_block(btree);
1083
1084         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
1085              level < nilfs_btree_height(btree) - 1;
1086              level++) {
1087                 node = nilfs_btree_get_nonroot_node(path, level);
1088                 if (nilfs_btree_node_get_nchildren(node) < ncblk) {
1089                         path[level].bp_op = nilfs_btree_do_insert;
1090                         stats->bs_nblocks++;
1091                         goto out;
1092                 }
1093
1094                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1095                 pindex = path[level + 1].bp_index;
1096
1097                 /* left sibling */
1098                 if (pindex > 0) {
1099                         sibptr = nilfs_btree_node_get_ptr(parent, pindex - 1,
1100                                                           ncmax);
1101                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1102                         if (ret < 0)
1103                                 goto err_out_child_node;
1104                         sib = (struct nilfs_btree_node *)bh->b_data;
1105                         if (nilfs_btree_node_get_nchildren(sib) < ncblk) {
1106                                 path[level].bp_sib_bh = bh;
1107                                 path[level].bp_op = nilfs_btree_carry_left;
1108                                 stats->bs_nblocks++;
1109                                 goto out;
1110                         } else {
1111                                 brelse(bh);
1112                         }
1113                 }
1114
1115                 /* right sibling */
1116                 if (pindex < nilfs_btree_node_get_nchildren(parent) - 1) {
1117                         sibptr = nilfs_btree_node_get_ptr(parent, pindex + 1,
1118                                                           ncmax);
1119                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1120                         if (ret < 0)
1121                                 goto err_out_child_node;
1122                         sib = (struct nilfs_btree_node *)bh->b_data;
1123                         if (nilfs_btree_node_get_nchildren(sib) < ncblk) {
1124                                 path[level].bp_sib_bh = bh;
1125                                 path[level].bp_op = nilfs_btree_carry_right;
1126                                 stats->bs_nblocks++;
1127                                 goto out;
1128                         } else {
1129                                 brelse(bh);
1130                         }
1131                 }
1132
1133                 /* split */
1134                 path[level].bp_newreq.bpr_ptr =
1135                         path[level - 1].bp_newreq.bpr_ptr + 1;
1136                 ret = nilfs_bmap_prepare_alloc_ptr(btree,
1137                                                    &path[level].bp_newreq, dat);
1138                 if (ret < 0)
1139                         goto err_out_child_node;
1140                 ret = nilfs_btree_get_new_block(btree,
1141                                                 path[level].bp_newreq.bpr_ptr,
1142                                                 &bh);
1143                 if (ret < 0)
1144                         goto err_out_curr_node;
1145
1146                 stats->bs_nblocks++;
1147
1148                 sib = (struct nilfs_btree_node *)bh->b_data;
1149                 nilfs_btree_node_init(sib, 0, level, 0, ncblk, NULL, NULL);
1150                 path[level].bp_sib_bh = bh;
1151                 path[level].bp_op = nilfs_btree_split;
1152         }
1153
1154         /* root */
1155         node = nilfs_btree_get_root(btree);
1156         if (nilfs_btree_node_get_nchildren(node) <
1157             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1158                 path[level].bp_op = nilfs_btree_do_insert;
1159                 stats->bs_nblocks++;
1160                 goto out;
1161         }
1162
1163         /* grow */
1164         path[level].bp_newreq.bpr_ptr = path[level - 1].bp_newreq.bpr_ptr + 1;
1165         ret = nilfs_bmap_prepare_alloc_ptr(btree, &path[level].bp_newreq, dat);
1166         if (ret < 0)
1167                 goto err_out_child_node;
1168         ret = nilfs_btree_get_new_block(btree, path[level].bp_newreq.bpr_ptr,
1169                                         &bh);
1170         if (ret < 0)
1171                 goto err_out_curr_node;
1172
1173         nilfs_btree_node_init((struct nilfs_btree_node *)bh->b_data,
1174                               0, level, 0, ncblk, NULL, NULL);
1175         path[level].bp_sib_bh = bh;
1176         path[level].bp_op = nilfs_btree_grow;
1177
1178         level++;
1179         path[level].bp_op = nilfs_btree_do_insert;
1180
1181         /* a newly-created node block and a data block are added */
1182         stats->bs_nblocks += 2;
1183
1184         /* success */
1185  out:
1186         *levelp = level;
1187         return ret;
1188
1189         /* error */
1190  err_out_curr_node:
1191         nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1192  err_out_child_node:
1193         for (level--; level > NILFS_BTREE_LEVEL_DATA; level--) {
1194                 nilfs_btnode_delete(path[level].bp_sib_bh);
1195                 nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1196
1197         }
1198
1199         nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1200  err_out_data:
1201         *levelp = level;
1202         stats->bs_nblocks = 0;
1203         return ret;
1204 }
1205
1206 static void nilfs_btree_commit_insert(struct nilfs_bmap *btree,
1207                                       struct nilfs_btree_path *path,
1208                                       int maxlevel, __u64 key, __u64 ptr)
1209 {
1210         struct inode *dat = NULL;
1211         int level;
1212
1213         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
1214         ptr = path[NILFS_BTREE_LEVEL_DATA].bp_newreq.bpr_ptr;
1215         if (NILFS_BMAP_USE_VBN(btree)) {
1216                 nilfs_bmap_set_target_v(btree, key, ptr);
1217                 dat = nilfs_bmap_get_dat(btree);
1218         }
1219
1220         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
1221                 nilfs_bmap_commit_alloc_ptr(btree,
1222                                             &path[level - 1].bp_newreq, dat);
1223                 path[level].bp_op(btree, path, level, &key, &ptr);
1224         }
1225
1226         if (!nilfs_bmap_dirty(btree))
1227                 nilfs_bmap_set_dirty(btree);
1228 }
1229
1230 static int nilfs_btree_insert(struct nilfs_bmap *btree, __u64 key, __u64 ptr)
1231 {
1232         struct nilfs_btree_path *path;
1233         struct nilfs_bmap_stats stats;
1234         int level, ret;
1235
1236         path = nilfs_btree_alloc_path();
1237         if (path == NULL)
1238                 return -ENOMEM;
1239
1240         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
1241                                     NILFS_BTREE_LEVEL_NODE_MIN, 0);
1242         if (ret != -ENOENT) {
1243                 if (ret == 0)
1244                         ret = -EEXIST;
1245                 goto out;
1246         }
1247
1248         ret = nilfs_btree_prepare_insert(btree, path, &level, key, ptr, &stats);
1249         if (ret < 0)
1250                 goto out;
1251         nilfs_btree_commit_insert(btree, path, level, key, ptr);
1252         nilfs_inode_add_blocks(btree->b_inode, stats.bs_nblocks);
1253
1254  out:
1255         nilfs_btree_free_path(path);
1256         return ret;
1257 }
1258
1259 static void nilfs_btree_do_delete(struct nilfs_bmap *btree,
1260                                   struct nilfs_btree_path *path,
1261                                   int level, __u64 *keyp, __u64 *ptrp)
1262 {
1263         struct nilfs_btree_node *node;
1264         int ncblk;
1265
1266         if (level < nilfs_btree_height(btree) - 1) {
1267                 node = nilfs_btree_get_nonroot_node(path, level);
1268                 ncblk = nilfs_btree_nchildren_per_block(btree);
1269                 nilfs_btree_node_delete(node, path[level].bp_index,
1270                                         keyp, ptrp, ncblk);
1271                 if (!buffer_dirty(path[level].bp_bh))
1272                         mark_buffer_dirty(path[level].bp_bh);
1273                 if (path[level].bp_index == 0)
1274                         nilfs_btree_promote_key(btree, path, level + 1,
1275                                 nilfs_btree_node_get_key(node, 0));
1276         } else {
1277                 node = nilfs_btree_get_root(btree);
1278                 nilfs_btree_node_delete(node, path[level].bp_index,
1279                                         keyp, ptrp,
1280                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
1281         }
1282 }
1283
1284 static void nilfs_btree_borrow_left(struct nilfs_bmap *btree,
1285                                     struct nilfs_btree_path *path,
1286                                     int level, __u64 *keyp, __u64 *ptrp)
1287 {
1288         struct nilfs_btree_node *node, *left;
1289         int nchildren, lnchildren, n, ncblk;
1290
1291         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1292
1293         node = nilfs_btree_get_nonroot_node(path, level);
1294         left = nilfs_btree_get_sib_node(path, level);
1295         nchildren = nilfs_btree_node_get_nchildren(node);
1296         lnchildren = nilfs_btree_node_get_nchildren(left);
1297         ncblk = nilfs_btree_nchildren_per_block(btree);
1298
1299         n = (nchildren + lnchildren) / 2 - nchildren;
1300
1301         nilfs_btree_node_move_right(left, node, n, ncblk, ncblk);
1302
1303         if (!buffer_dirty(path[level].bp_bh))
1304                 mark_buffer_dirty(path[level].bp_bh);
1305         if (!buffer_dirty(path[level].bp_sib_bh))
1306                 mark_buffer_dirty(path[level].bp_sib_bh);
1307
1308         nilfs_btree_promote_key(btree, path, level + 1,
1309                                 nilfs_btree_node_get_key(node, 0));
1310
1311         brelse(path[level].bp_sib_bh);
1312         path[level].bp_sib_bh = NULL;
1313         path[level].bp_index += n;
1314 }
1315
1316 static void nilfs_btree_borrow_right(struct nilfs_bmap *btree,
1317                                      struct nilfs_btree_path *path,
1318                                      int level, __u64 *keyp, __u64 *ptrp)
1319 {
1320         struct nilfs_btree_node *node, *right;
1321         int nchildren, rnchildren, n, ncblk;
1322
1323         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1324
1325         node = nilfs_btree_get_nonroot_node(path, level);
1326         right = nilfs_btree_get_sib_node(path, level);
1327         nchildren = nilfs_btree_node_get_nchildren(node);
1328         rnchildren = nilfs_btree_node_get_nchildren(right);
1329         ncblk = nilfs_btree_nchildren_per_block(btree);
1330
1331         n = (nchildren + rnchildren) / 2 - nchildren;
1332
1333         nilfs_btree_node_move_left(node, right, n, ncblk, ncblk);
1334
1335         if (!buffer_dirty(path[level].bp_bh))
1336                 mark_buffer_dirty(path[level].bp_bh);
1337         if (!buffer_dirty(path[level].bp_sib_bh))
1338                 mark_buffer_dirty(path[level].bp_sib_bh);
1339
1340         path[level + 1].bp_index++;
1341         nilfs_btree_promote_key(btree, path, level + 1,
1342                                 nilfs_btree_node_get_key(right, 0));
1343         path[level + 1].bp_index--;
1344
1345         brelse(path[level].bp_sib_bh);
1346         path[level].bp_sib_bh = NULL;
1347 }
1348
1349 static void nilfs_btree_concat_left(struct nilfs_bmap *btree,
1350                                     struct nilfs_btree_path *path,
1351                                     int level, __u64 *keyp, __u64 *ptrp)
1352 {
1353         struct nilfs_btree_node *node, *left;
1354         int n, ncblk;
1355
1356         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1357
1358         node = nilfs_btree_get_nonroot_node(path, level);
1359         left = nilfs_btree_get_sib_node(path, level);
1360         ncblk = nilfs_btree_nchildren_per_block(btree);
1361
1362         n = nilfs_btree_node_get_nchildren(node);
1363
1364         nilfs_btree_node_move_left(left, node, n, ncblk, ncblk);
1365
1366         if (!buffer_dirty(path[level].bp_sib_bh))
1367                 mark_buffer_dirty(path[level].bp_sib_bh);
1368
1369         nilfs_btnode_delete(path[level].bp_bh);
1370         path[level].bp_bh = path[level].bp_sib_bh;
1371         path[level].bp_sib_bh = NULL;
1372         path[level].bp_index += nilfs_btree_node_get_nchildren(left);
1373 }
1374
1375 static void nilfs_btree_concat_right(struct nilfs_bmap *btree,
1376                                      struct nilfs_btree_path *path,
1377                                      int level, __u64 *keyp, __u64 *ptrp)
1378 {
1379         struct nilfs_btree_node *node, *right;
1380         int n, ncblk;
1381
1382         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1383
1384         node = nilfs_btree_get_nonroot_node(path, level);
1385         right = nilfs_btree_get_sib_node(path, level);
1386         ncblk = nilfs_btree_nchildren_per_block(btree);
1387
1388         n = nilfs_btree_node_get_nchildren(right);
1389
1390         nilfs_btree_node_move_left(node, right, n, ncblk, ncblk);
1391
1392         if (!buffer_dirty(path[level].bp_bh))
1393                 mark_buffer_dirty(path[level].bp_bh);
1394
1395         nilfs_btnode_delete(path[level].bp_sib_bh);
1396         path[level].bp_sib_bh = NULL;
1397         path[level + 1].bp_index++;
1398 }
1399
1400 static void nilfs_btree_shrink(struct nilfs_bmap *btree,
1401                                struct nilfs_btree_path *path,
1402                                int level, __u64 *keyp, __u64 *ptrp)
1403 {
1404         struct nilfs_btree_node *root, *child;
1405         int n, ncblk;
1406
1407         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1408
1409         root = nilfs_btree_get_root(btree);
1410         child = nilfs_btree_get_nonroot_node(path, level);
1411         ncblk = nilfs_btree_nchildren_per_block(btree);
1412
1413         nilfs_btree_node_delete(root, 0, NULL, NULL,
1414                                 NILFS_BTREE_ROOT_NCHILDREN_MAX);
1415         nilfs_btree_node_set_level(root, level);
1416         n = nilfs_btree_node_get_nchildren(child);
1417         nilfs_btree_node_move_left(root, child, n,
1418                                    NILFS_BTREE_ROOT_NCHILDREN_MAX, ncblk);
1419
1420         nilfs_btnode_delete(path[level].bp_bh);
1421         path[level].bp_bh = NULL;
1422 }
1423
1424 static void nilfs_btree_nop(struct nilfs_bmap *btree,
1425                             struct nilfs_btree_path *path,
1426                             int level, __u64 *keyp, __u64 *ptrp)
1427 {
1428 }
1429
1430 static int nilfs_btree_prepare_delete(struct nilfs_bmap *btree,
1431                                       struct nilfs_btree_path *path,
1432                                       int *levelp,
1433                                       struct nilfs_bmap_stats *stats,
1434                                       struct inode *dat)
1435 {
1436         struct buffer_head *bh;
1437         struct nilfs_btree_node *node, *parent, *sib;
1438         __u64 sibptr;
1439         int pindex, dindex, level, ncmin, ncmax, ncblk, ret;
1440
1441         ret = 0;
1442         stats->bs_nblocks = 0;
1443         ncmin = NILFS_BTREE_NODE_NCHILDREN_MIN(nilfs_btree_node_size(btree));
1444         ncblk = nilfs_btree_nchildren_per_block(btree);
1445
1446         for (level = NILFS_BTREE_LEVEL_NODE_MIN, dindex = path[level].bp_index;
1447              level < nilfs_btree_height(btree) - 1;
1448              level++) {
1449                 node = nilfs_btree_get_nonroot_node(path, level);
1450                 path[level].bp_oldreq.bpr_ptr =
1451                         nilfs_btree_node_get_ptr(node, dindex, ncblk);
1452                 ret = nilfs_bmap_prepare_end_ptr(btree,
1453                                                  &path[level].bp_oldreq, dat);
1454                 if (ret < 0)
1455                         goto err_out_child_node;
1456
1457                 if (nilfs_btree_node_get_nchildren(node) > ncmin) {
1458                         path[level].bp_op = nilfs_btree_do_delete;
1459                         stats->bs_nblocks++;
1460                         goto out;
1461                 }
1462
1463                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1464                 pindex = path[level + 1].bp_index;
1465                 dindex = pindex;
1466
1467                 if (pindex > 0) {
1468                         /* left sibling */
1469                         sibptr = nilfs_btree_node_get_ptr(parent, pindex - 1,
1470                                                           ncmax);
1471                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1472                         if (ret < 0)
1473                                 goto err_out_curr_node;
1474                         sib = (struct nilfs_btree_node *)bh->b_data;
1475                         if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
1476                                 path[level].bp_sib_bh = bh;
1477                                 path[level].bp_op = nilfs_btree_borrow_left;
1478                                 stats->bs_nblocks++;
1479                                 goto out;
1480                         } else {
1481                                 path[level].bp_sib_bh = bh;
1482                                 path[level].bp_op = nilfs_btree_concat_left;
1483                                 stats->bs_nblocks++;
1484                                 /* continue; */
1485                         }
1486                 } else if (pindex <
1487                            nilfs_btree_node_get_nchildren(parent) - 1) {
1488                         /* right sibling */
1489                         sibptr = nilfs_btree_node_get_ptr(parent, pindex + 1,
1490                                                           ncmax);
1491                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1492                         if (ret < 0)
1493                                 goto err_out_curr_node;
1494                         sib = (struct nilfs_btree_node *)bh->b_data;
1495                         if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
1496                                 path[level].bp_sib_bh = bh;
1497                                 path[level].bp_op = nilfs_btree_borrow_right;
1498                                 stats->bs_nblocks++;
1499                                 goto out;
1500                         } else {
1501                                 path[level].bp_sib_bh = bh;
1502                                 path[level].bp_op = nilfs_btree_concat_right;
1503                                 stats->bs_nblocks++;
1504                                 /*
1505                                  * When merging right sibling node
1506                                  * into the current node, pointer to
1507                                  * the right sibling node must be
1508                                  * terminated instead.  The adjustment
1509                                  * below is required for that.
1510                                  */
1511                                 dindex = pindex + 1;
1512                                 /* continue; */
1513                         }
1514                 } else {
1515                         /* no siblings */
1516                         /* the only child of the root node */
1517                         WARN_ON(level != nilfs_btree_height(btree) - 2);
1518                         if (nilfs_btree_node_get_nchildren(node) - 1 <=
1519                             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1520                                 path[level].bp_op = nilfs_btree_shrink;
1521                                 stats->bs_nblocks += 2;
1522                                 level++;
1523                                 path[level].bp_op = nilfs_btree_nop;
1524                                 goto shrink_root_child;
1525                         } else {
1526                                 path[level].bp_op = nilfs_btree_do_delete;
1527                                 stats->bs_nblocks++;
1528                                 goto out;
1529                         }
1530                 }
1531         }
1532
1533         /* child of the root node is deleted */
1534         path[level].bp_op = nilfs_btree_do_delete;
1535         stats->bs_nblocks++;
1536
1537 shrink_root_child:
1538         node = nilfs_btree_get_root(btree);
1539         path[level].bp_oldreq.bpr_ptr =
1540                 nilfs_btree_node_get_ptr(node, dindex,
1541                                          NILFS_BTREE_ROOT_NCHILDREN_MAX);
1542
1543         ret = nilfs_bmap_prepare_end_ptr(btree, &path[level].bp_oldreq, dat);
1544         if (ret < 0)
1545                 goto err_out_child_node;
1546
1547         /* success */
1548  out:
1549         *levelp = level;
1550         return ret;
1551
1552         /* error */
1553  err_out_curr_node:
1554         nilfs_bmap_abort_end_ptr(btree, &path[level].bp_oldreq, dat);
1555  err_out_child_node:
1556         for (level--; level >= NILFS_BTREE_LEVEL_NODE_MIN; level--) {
1557                 brelse(path[level].bp_sib_bh);
1558                 nilfs_bmap_abort_end_ptr(btree, &path[level].bp_oldreq, dat);
1559         }
1560         *levelp = level;
1561         stats->bs_nblocks = 0;
1562         return ret;
1563 }
1564
1565 static void nilfs_btree_commit_delete(struct nilfs_bmap *btree,
1566                                       struct nilfs_btree_path *path,
1567                                       int maxlevel, struct inode *dat)
1568 {
1569         int level;
1570
1571         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
1572                 nilfs_bmap_commit_end_ptr(btree, &path[level].bp_oldreq, dat);
1573                 path[level].bp_op(btree, path, level, NULL, NULL);
1574         }
1575
1576         if (!nilfs_bmap_dirty(btree))
1577                 nilfs_bmap_set_dirty(btree);
1578 }
1579
1580 static int nilfs_btree_delete(struct nilfs_bmap *btree, __u64 key)
1581
1582 {
1583         struct nilfs_btree_path *path;
1584         struct nilfs_bmap_stats stats;
1585         struct inode *dat;
1586         int level, ret;
1587
1588         path = nilfs_btree_alloc_path();
1589         if (path == NULL)
1590                 return -ENOMEM;
1591
1592         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
1593                                     NILFS_BTREE_LEVEL_NODE_MIN, 0);
1594         if (ret < 0)
1595                 goto out;
1596
1597
1598         dat = NILFS_BMAP_USE_VBN(btree) ? nilfs_bmap_get_dat(btree) : NULL;
1599
1600         ret = nilfs_btree_prepare_delete(btree, path, &level, &stats, dat);
1601         if (ret < 0)
1602                 goto out;
1603         nilfs_btree_commit_delete(btree, path, level, dat);
1604         nilfs_inode_sub_blocks(btree->b_inode, stats.bs_nblocks);
1605
1606 out:
1607         nilfs_btree_free_path(path);
1608         return ret;
1609 }
1610
1611 static int nilfs_btree_seek_key(const struct nilfs_bmap *btree, __u64 start,
1612                                 __u64 *keyp)
1613 {
1614         struct nilfs_btree_path *path;
1615         const int minlevel = NILFS_BTREE_LEVEL_NODE_MIN;
1616         int ret;
1617
1618         path = nilfs_btree_alloc_path();
1619         if (!path)
1620                 return -ENOMEM;
1621
1622         ret = nilfs_btree_do_lookup(btree, path, start, NULL, minlevel, 0);
1623         if (!ret)
1624                 *keyp = start;
1625         else if (ret == -ENOENT)
1626                 ret = nilfs_btree_get_next_key(btree, path, minlevel, keyp);
1627
1628         nilfs_btree_free_path(path);
1629         return ret;
1630 }
1631
1632 static int nilfs_btree_last_key(const struct nilfs_bmap *btree, __u64 *keyp)
1633 {
1634         struct nilfs_btree_path *path;
1635         int ret;
1636
1637         path = nilfs_btree_alloc_path();
1638         if (path == NULL)
1639                 return -ENOMEM;
1640
1641         ret = nilfs_btree_do_lookup_last(btree, path, keyp, NULL);
1642
1643         nilfs_btree_free_path(path);
1644
1645         return ret;
1646 }
1647
1648 static int nilfs_btree_check_delete(struct nilfs_bmap *btree, __u64 key)
1649 {
1650         struct buffer_head *bh;
1651         struct nilfs_btree_node *root, *node;
1652         __u64 maxkey, nextmaxkey;
1653         __u64 ptr;
1654         int nchildren, ret;
1655
1656         root = nilfs_btree_get_root(btree);
1657         switch (nilfs_btree_height(btree)) {
1658         case 2:
1659                 bh = NULL;
1660                 node = root;
1661                 break;
1662         case 3:
1663                 nchildren = nilfs_btree_node_get_nchildren(root);
1664                 if (nchildren > 1)
1665                         return 0;
1666                 ptr = nilfs_btree_node_get_ptr(root, nchildren - 1,
1667                                                NILFS_BTREE_ROOT_NCHILDREN_MAX);
1668                 ret = nilfs_btree_get_block(btree, ptr, &bh);
1669                 if (ret < 0)
1670                         return ret;
1671                 node = (struct nilfs_btree_node *)bh->b_data;
1672                 break;
1673         default:
1674                 return 0;
1675         }
1676
1677         nchildren = nilfs_btree_node_get_nchildren(node);
1678         maxkey = nilfs_btree_node_get_key(node, nchildren - 1);
1679         nextmaxkey = (nchildren > 1) ?
1680                 nilfs_btree_node_get_key(node, nchildren - 2) : 0;
1681         if (bh != NULL)
1682                 brelse(bh);
1683
1684         return (maxkey == key) && (nextmaxkey < NILFS_BMAP_LARGE_LOW);
1685 }
1686
1687 static int nilfs_btree_gather_data(struct nilfs_bmap *btree,
1688                                    __u64 *keys, __u64 *ptrs, int nitems)
1689 {
1690         struct buffer_head *bh;
1691         struct nilfs_btree_node *node, *root;
1692         __le64 *dkeys;
1693         __le64 *dptrs;
1694         __u64 ptr;
1695         int nchildren, ncmax, i, ret;
1696
1697         root = nilfs_btree_get_root(btree);
1698         switch (nilfs_btree_height(btree)) {
1699         case 2:
1700                 bh = NULL;
1701                 node = root;
1702                 ncmax = NILFS_BTREE_ROOT_NCHILDREN_MAX;
1703                 break;
1704         case 3:
1705                 nchildren = nilfs_btree_node_get_nchildren(root);
1706                 WARN_ON(nchildren > 1);
1707                 ptr = nilfs_btree_node_get_ptr(root, nchildren - 1,
1708                                                NILFS_BTREE_ROOT_NCHILDREN_MAX);
1709                 ret = nilfs_btree_get_block(btree, ptr, &bh);
1710                 if (ret < 0)
1711                         return ret;
1712                 node = (struct nilfs_btree_node *)bh->b_data;
1713                 ncmax = nilfs_btree_nchildren_per_block(btree);
1714                 break;
1715         default:
1716                 node = NULL;
1717                 return -EINVAL;
1718         }
1719
1720         nchildren = nilfs_btree_node_get_nchildren(node);
1721         if (nchildren < nitems)
1722                 nitems = nchildren;
1723         dkeys = nilfs_btree_node_dkeys(node);
1724         dptrs = nilfs_btree_node_dptrs(node, ncmax);
1725         for (i = 0; i < nitems; i++) {
1726                 keys[i] = le64_to_cpu(dkeys[i]);
1727                 ptrs[i] = le64_to_cpu(dptrs[i]);
1728         }
1729
1730         if (bh != NULL)
1731                 brelse(bh);
1732
1733         return nitems;
1734 }
1735
1736 static int
1737 nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *btree, __u64 key,
1738                                        union nilfs_bmap_ptr_req *dreq,
1739                                        union nilfs_bmap_ptr_req *nreq,
1740                                        struct buffer_head **bhp,
1741                                        struct nilfs_bmap_stats *stats)
1742 {
1743         struct buffer_head *bh;
1744         struct inode *dat = NULL;
1745         int ret;
1746
1747         stats->bs_nblocks = 0;
1748
1749         /* for data */
1750         /* cannot find near ptr */
1751         if (NILFS_BMAP_USE_VBN(btree)) {
1752                 dreq->bpr_ptr = nilfs_btree_find_target_v(btree, NULL, key);
1753                 dat = nilfs_bmap_get_dat(btree);
1754         }
1755
1756         ret = nilfs_attach_btree_node_cache(&NILFS_BMAP_I(btree)->vfs_inode);
1757         if (ret < 0)
1758                 return ret;
1759
1760         ret = nilfs_bmap_prepare_alloc_ptr(btree, dreq, dat);
1761         if (ret < 0)
1762                 return ret;
1763
1764         *bhp = NULL;
1765         stats->bs_nblocks++;
1766         if (nreq != NULL) {
1767                 nreq->bpr_ptr = dreq->bpr_ptr + 1;
1768                 ret = nilfs_bmap_prepare_alloc_ptr(btree, nreq, dat);
1769                 if (ret < 0)
1770                         goto err_out_dreq;
1771
1772                 ret = nilfs_btree_get_new_block(btree, nreq->bpr_ptr, &bh);
1773                 if (ret < 0)
1774                         goto err_out_nreq;
1775
1776                 *bhp = bh;
1777                 stats->bs_nblocks++;
1778         }
1779
1780         /* success */
1781         return 0;
1782
1783         /* error */
1784  err_out_nreq:
1785         nilfs_bmap_abort_alloc_ptr(btree, nreq, dat);
1786  err_out_dreq:
1787         nilfs_bmap_abort_alloc_ptr(btree, dreq, dat);
1788         stats->bs_nblocks = 0;
1789         return ret;
1790
1791 }
1792
1793 static void
1794 nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *btree,
1795                                       __u64 key, __u64 ptr,
1796                                       const __u64 *keys, const __u64 *ptrs,
1797                                       int n,
1798                                       union nilfs_bmap_ptr_req *dreq,
1799                                       union nilfs_bmap_ptr_req *nreq,
1800                                       struct buffer_head *bh)
1801 {
1802         struct nilfs_btree_node *node;
1803         struct inode *dat;
1804         __u64 tmpptr;
1805         int ncblk;
1806
1807         /* free resources */
1808         if (btree->b_ops->bop_clear != NULL)
1809                 btree->b_ops->bop_clear(btree);
1810
1811         /* ptr must be a pointer to a buffer head. */
1812         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
1813
1814         /* convert and insert */
1815         dat = NILFS_BMAP_USE_VBN(btree) ? nilfs_bmap_get_dat(btree) : NULL;
1816         __nilfs_btree_init(btree);
1817         if (nreq != NULL) {
1818                 nilfs_bmap_commit_alloc_ptr(btree, dreq, dat);
1819                 nilfs_bmap_commit_alloc_ptr(btree, nreq, dat);
1820
1821                 /* create child node at level 1 */
1822                 node = (struct nilfs_btree_node *)bh->b_data;
1823                 ncblk = nilfs_btree_nchildren_per_block(btree);
1824                 nilfs_btree_node_init(node, 0, 1, n, ncblk, keys, ptrs);
1825                 nilfs_btree_node_insert(node, n, key, dreq->bpr_ptr, ncblk);
1826                 if (!buffer_dirty(bh))
1827                         mark_buffer_dirty(bh);
1828                 if (!nilfs_bmap_dirty(btree))
1829                         nilfs_bmap_set_dirty(btree);
1830
1831                 brelse(bh);
1832
1833                 /* create root node at level 2 */
1834                 node = nilfs_btree_get_root(btree);
1835                 tmpptr = nreq->bpr_ptr;
1836                 nilfs_btree_node_init(node, NILFS_BTREE_NODE_ROOT, 2, 1,
1837                                       NILFS_BTREE_ROOT_NCHILDREN_MAX,
1838                                       &keys[0], &tmpptr);
1839         } else {
1840                 nilfs_bmap_commit_alloc_ptr(btree, dreq, dat);
1841
1842                 /* create root node at level 1 */
1843                 node = nilfs_btree_get_root(btree);
1844                 nilfs_btree_node_init(node, NILFS_BTREE_NODE_ROOT, 1, n,
1845                                       NILFS_BTREE_ROOT_NCHILDREN_MAX,
1846                                       keys, ptrs);
1847                 nilfs_btree_node_insert(node, n, key, dreq->bpr_ptr,
1848                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
1849                 if (!nilfs_bmap_dirty(btree))
1850                         nilfs_bmap_set_dirty(btree);
1851         }
1852
1853         if (NILFS_BMAP_USE_VBN(btree))
1854                 nilfs_bmap_set_target_v(btree, key, dreq->bpr_ptr);
1855 }
1856
1857 /**
1858  * nilfs_btree_convert_and_insert -
1859  * @bmap:
1860  * @key:
1861  * @ptr:
1862  * @keys:
1863  * @ptrs:
1864  * @n:
1865  */
1866 int nilfs_btree_convert_and_insert(struct nilfs_bmap *btree,
1867                                    __u64 key, __u64 ptr,
1868                                    const __u64 *keys, const __u64 *ptrs, int n)
1869 {
1870         struct buffer_head *bh = NULL;
1871         union nilfs_bmap_ptr_req dreq, nreq, *di, *ni;
1872         struct nilfs_bmap_stats stats;
1873         int ret;
1874
1875         if (n + 1 <= NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1876                 di = &dreq;
1877                 ni = NULL;
1878         } else if ((n + 1) <= NILFS_BTREE_NODE_NCHILDREN_MAX(
1879                            nilfs_btree_node_size(btree))) {
1880                 di = &dreq;
1881                 ni = &nreq;
1882         } else {
1883                 di = NULL;
1884                 ni = NULL;
1885                 BUG();
1886         }
1887
1888         ret = nilfs_btree_prepare_convert_and_insert(btree, key, di, ni, &bh,
1889                                                      &stats);
1890         if (ret < 0)
1891                 return ret;
1892         nilfs_btree_commit_convert_and_insert(btree, key, ptr, keys, ptrs, n,
1893                                               di, ni, bh);
1894         nilfs_inode_add_blocks(btree->b_inode, stats.bs_nblocks);
1895         return 0;
1896 }
1897
1898 static int nilfs_btree_propagate_p(struct nilfs_bmap *btree,
1899                                    struct nilfs_btree_path *path,
1900                                    int level,
1901                                    struct buffer_head *bh)
1902 {
1903         while ((++level < nilfs_btree_height(btree) - 1) &&
1904                !buffer_dirty(path[level].bp_bh))
1905                 mark_buffer_dirty(path[level].bp_bh);
1906
1907         return 0;
1908 }
1909
1910 static int nilfs_btree_prepare_update_v(struct nilfs_bmap *btree,
1911                                         struct nilfs_btree_path *path,
1912                                         int level, struct inode *dat)
1913 {
1914         struct nilfs_btree_node *parent;
1915         int ncmax, ret;
1916
1917         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1918         path[level].bp_oldreq.bpr_ptr =
1919                 nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
1920                                          ncmax);
1921         path[level].bp_newreq.bpr_ptr = path[level].bp_oldreq.bpr_ptr + 1;
1922         ret = nilfs_dat_prepare_update(dat, &path[level].bp_oldreq.bpr_req,
1923                                        &path[level].bp_newreq.bpr_req);
1924         if (ret < 0)
1925                 return ret;
1926
1927         if (buffer_nilfs_node(path[level].bp_bh)) {
1928                 path[level].bp_ctxt.oldkey = path[level].bp_oldreq.bpr_ptr;
1929                 path[level].bp_ctxt.newkey = path[level].bp_newreq.bpr_ptr;
1930                 path[level].bp_ctxt.bh = path[level].bp_bh;
1931                 ret = nilfs_btnode_prepare_change_key(
1932                         NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
1933                         &path[level].bp_ctxt);
1934                 if (ret < 0) {
1935                         nilfs_dat_abort_update(dat,
1936                                                &path[level].bp_oldreq.bpr_req,
1937                                                &path[level].bp_newreq.bpr_req);
1938                         return ret;
1939                 }
1940         }
1941
1942         return 0;
1943 }
1944
1945 static void nilfs_btree_commit_update_v(struct nilfs_bmap *btree,
1946                                         struct nilfs_btree_path *path,
1947                                         int level, struct inode *dat)
1948 {
1949         struct nilfs_btree_node *parent;
1950         int ncmax;
1951
1952         nilfs_dat_commit_update(dat, &path[level].bp_oldreq.bpr_req,
1953                                 &path[level].bp_newreq.bpr_req,
1954                                 btree->b_ptr_type == NILFS_BMAP_PTR_VS);
1955
1956         if (buffer_nilfs_node(path[level].bp_bh)) {
1957                 nilfs_btnode_commit_change_key(
1958                         NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
1959                         &path[level].bp_ctxt);
1960                 path[level].bp_bh = path[level].bp_ctxt.bh;
1961         }
1962         set_buffer_nilfs_volatile(path[level].bp_bh);
1963
1964         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1965         nilfs_btree_node_set_ptr(parent, path[level + 1].bp_index,
1966                                  path[level].bp_newreq.bpr_ptr, ncmax);
1967 }
1968
1969 static void nilfs_btree_abort_update_v(struct nilfs_bmap *btree,
1970                                        struct nilfs_btree_path *path,
1971                                        int level, struct inode *dat)
1972 {
1973         nilfs_dat_abort_update(dat, &path[level].bp_oldreq.bpr_req,
1974                                &path[level].bp_newreq.bpr_req);
1975         if (buffer_nilfs_node(path[level].bp_bh))
1976                 nilfs_btnode_abort_change_key(
1977                         NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
1978                         &path[level].bp_ctxt);
1979 }
1980
1981 static int nilfs_btree_prepare_propagate_v(struct nilfs_bmap *btree,
1982                                            struct nilfs_btree_path *path,
1983                                            int minlevel, int *maxlevelp,
1984                                            struct inode *dat)
1985 {
1986         int level, ret;
1987
1988         level = minlevel;
1989         if (!buffer_nilfs_volatile(path[level].bp_bh)) {
1990                 ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
1991                 if (ret < 0)
1992                         return ret;
1993         }
1994         while ((++level < nilfs_btree_height(btree) - 1) &&
1995                !buffer_dirty(path[level].bp_bh)) {
1996
1997                 WARN_ON(buffer_nilfs_volatile(path[level].bp_bh));
1998                 ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
1999                 if (ret < 0)
2000                         goto out;
2001         }
2002
2003         /* success */
2004         *maxlevelp = level - 1;
2005         return 0;
2006
2007         /* error */
2008  out:
2009         while (--level > minlevel)
2010                 nilfs_btree_abort_update_v(btree, path, level, dat);
2011         if (!buffer_nilfs_volatile(path[level].bp_bh))
2012                 nilfs_btree_abort_update_v(btree, path, level, dat);
2013         return ret;
2014 }
2015
2016 static void nilfs_btree_commit_propagate_v(struct nilfs_bmap *btree,
2017                                            struct nilfs_btree_path *path,
2018                                            int minlevel, int maxlevel,
2019                                            struct buffer_head *bh,
2020                                            struct inode *dat)
2021 {
2022         int level;
2023
2024         if (!buffer_nilfs_volatile(path[minlevel].bp_bh))
2025                 nilfs_btree_commit_update_v(btree, path, minlevel, dat);
2026
2027         for (level = minlevel + 1; level <= maxlevel; level++)
2028                 nilfs_btree_commit_update_v(btree, path, level, dat);
2029 }
2030
2031 static int nilfs_btree_propagate_v(struct nilfs_bmap *btree,
2032                                    struct nilfs_btree_path *path,
2033                                    int level, struct buffer_head *bh)
2034 {
2035         int maxlevel = 0, ret;
2036         struct nilfs_btree_node *parent;
2037         struct inode *dat = nilfs_bmap_get_dat(btree);
2038         __u64 ptr;
2039         int ncmax;
2040
2041         get_bh(bh);
2042         path[level].bp_bh = bh;
2043         ret = nilfs_btree_prepare_propagate_v(btree, path, level, &maxlevel,
2044                                               dat);
2045         if (ret < 0)
2046                 goto out;
2047
2048         if (buffer_nilfs_volatile(path[level].bp_bh)) {
2049                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2050                 ptr = nilfs_btree_node_get_ptr(parent,
2051                                                path[level + 1].bp_index,
2052                                                ncmax);
2053                 ret = nilfs_dat_mark_dirty(dat, ptr);
2054                 if (ret < 0)
2055                         goto out;
2056         }
2057
2058         nilfs_btree_commit_propagate_v(btree, path, level, maxlevel, bh, dat);
2059
2060  out:
2061         brelse(path[level].bp_bh);
2062         path[level].bp_bh = NULL;
2063         return ret;
2064 }
2065
2066 static int nilfs_btree_propagate(struct nilfs_bmap *btree,
2067                                  struct buffer_head *bh)
2068 {
2069         struct nilfs_btree_path *path;
2070         struct nilfs_btree_node *node;
2071         __u64 key;
2072         int level, ret;
2073
2074         WARN_ON(!buffer_dirty(bh));
2075
2076         path = nilfs_btree_alloc_path();
2077         if (path == NULL)
2078                 return -ENOMEM;
2079
2080         if (buffer_nilfs_node(bh)) {
2081                 node = (struct nilfs_btree_node *)bh->b_data;
2082                 key = nilfs_btree_node_get_key(node, 0);
2083                 level = nilfs_btree_node_get_level(node);
2084         } else {
2085                 key = nilfs_bmap_data_get_key(btree, bh);
2086                 level = NILFS_BTREE_LEVEL_DATA;
2087         }
2088
2089         ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
2090         if (ret < 0) {
2091                 if (unlikely(ret == -ENOENT))
2092                         nilfs_msg(btree->b_inode->i_sb, KERN_CRIT,
2093                                   "writing node/leaf block does not appear in b-tree (ino=%lu) at key=%llu, level=%d",
2094                                   btree->b_inode->i_ino,
2095                                   (unsigned long long)key, level);
2096                 goto out;
2097         }
2098
2099         ret = NILFS_BMAP_USE_VBN(btree) ?
2100                 nilfs_btree_propagate_v(btree, path, level, bh) :
2101                 nilfs_btree_propagate_p(btree, path, level, bh);
2102
2103  out:
2104         nilfs_btree_free_path(path);
2105
2106         return ret;
2107 }
2108
2109 static int nilfs_btree_propagate_gc(struct nilfs_bmap *btree,
2110                                     struct buffer_head *bh)
2111 {
2112         return nilfs_dat_mark_dirty(nilfs_bmap_get_dat(btree), bh->b_blocknr);
2113 }
2114
2115 static void nilfs_btree_add_dirty_buffer(struct nilfs_bmap *btree,
2116                                          struct list_head *lists,
2117                                          struct buffer_head *bh)
2118 {
2119         struct list_head *head;
2120         struct buffer_head *cbh;
2121         struct nilfs_btree_node *node, *cnode;
2122         __u64 key, ckey;
2123         int level;
2124
2125         get_bh(bh);
2126         node = (struct nilfs_btree_node *)bh->b_data;
2127         key = nilfs_btree_node_get_key(node, 0);
2128         level = nilfs_btree_node_get_level(node);
2129         if (level < NILFS_BTREE_LEVEL_NODE_MIN ||
2130             level >= NILFS_BTREE_LEVEL_MAX) {
2131                 dump_stack();
2132                 nilfs_msg(btree->b_inode->i_sb, KERN_WARNING,
2133                           "invalid btree level: %d (key=%llu, ino=%lu, blocknr=%llu)",
2134                           level, (unsigned long long)key,
2135                           btree->b_inode->i_ino,
2136                           (unsigned long long)bh->b_blocknr);
2137                 return;
2138         }
2139
2140         list_for_each(head, &lists[level]) {
2141                 cbh = list_entry(head, struct buffer_head, b_assoc_buffers);
2142                 cnode = (struct nilfs_btree_node *)cbh->b_data;
2143                 ckey = nilfs_btree_node_get_key(cnode, 0);
2144                 if (key < ckey)
2145                         break;
2146         }
2147         list_add_tail(&bh->b_assoc_buffers, head);
2148 }
2149
2150 static void nilfs_btree_lookup_dirty_buffers(struct nilfs_bmap *btree,
2151                                              struct list_head *listp)
2152 {
2153         struct inode *btnc_inode = NILFS_BMAP_I(btree)->i_assoc_inode;
2154         struct address_space *btcache = btnc_inode->i_mapping;
2155         struct list_head lists[NILFS_BTREE_LEVEL_MAX];
2156         struct pagevec pvec;
2157         struct buffer_head *bh, *head;
2158         pgoff_t index = 0;
2159         int level, i;
2160
2161         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
2162              level < NILFS_BTREE_LEVEL_MAX;
2163              level++)
2164                 INIT_LIST_HEAD(&lists[level]);
2165
2166         pagevec_init(&pvec);
2167
2168         while (pagevec_lookup_tag(&pvec, btcache, &index,
2169                                         PAGECACHE_TAG_DIRTY)) {
2170                 for (i = 0; i < pagevec_count(&pvec); i++) {
2171                         bh = head = page_buffers(pvec.pages[i]);
2172                         do {
2173                                 if (buffer_dirty(bh))
2174                                         nilfs_btree_add_dirty_buffer(btree,
2175                                                                      lists, bh);
2176                         } while ((bh = bh->b_this_page) != head);
2177                 }
2178                 pagevec_release(&pvec);
2179                 cond_resched();
2180         }
2181
2182         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
2183              level < NILFS_BTREE_LEVEL_MAX;
2184              level++)
2185                 list_splice_tail(&lists[level], listp);
2186 }
2187
2188 static int nilfs_btree_assign_p(struct nilfs_bmap *btree,
2189                                 struct nilfs_btree_path *path,
2190                                 int level,
2191                                 struct buffer_head **bh,
2192                                 sector_t blocknr,
2193                                 union nilfs_binfo *binfo)
2194 {
2195         struct nilfs_btree_node *parent;
2196         __u64 key;
2197         __u64 ptr;
2198         int ncmax, ret;
2199
2200         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2201         ptr = nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
2202                                        ncmax);
2203         if (buffer_nilfs_node(*bh)) {
2204                 path[level].bp_ctxt.oldkey = ptr;
2205                 path[level].bp_ctxt.newkey = blocknr;
2206                 path[level].bp_ctxt.bh = *bh;
2207                 ret = nilfs_btnode_prepare_change_key(
2208                         NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
2209                         &path[level].bp_ctxt);
2210                 if (ret < 0)
2211                         return ret;
2212                 nilfs_btnode_commit_change_key(
2213                         NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
2214                         &path[level].bp_ctxt);
2215                 *bh = path[level].bp_ctxt.bh;
2216         }
2217
2218         nilfs_btree_node_set_ptr(parent, path[level + 1].bp_index, blocknr,
2219                                  ncmax);
2220
2221         key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
2222         /* on-disk format */
2223         binfo->bi_dat.bi_blkoff = cpu_to_le64(key);
2224         binfo->bi_dat.bi_level = level;
2225
2226         return 0;
2227 }
2228
2229 static int nilfs_btree_assign_v(struct nilfs_bmap *btree,
2230                                 struct nilfs_btree_path *path,
2231                                 int level,
2232                                 struct buffer_head **bh,
2233                                 sector_t blocknr,
2234                                 union nilfs_binfo *binfo)
2235 {
2236         struct nilfs_btree_node *parent;
2237         struct inode *dat = nilfs_bmap_get_dat(btree);
2238         __u64 key;
2239         __u64 ptr;
2240         union nilfs_bmap_ptr_req req;
2241         int ncmax, ret;
2242
2243         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2244         ptr = nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
2245                                        ncmax);
2246         req.bpr_ptr = ptr;
2247         ret = nilfs_dat_prepare_start(dat, &req.bpr_req);
2248         if (ret < 0)
2249                 return ret;
2250         nilfs_dat_commit_start(dat, &req.bpr_req, blocknr);
2251
2252         key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
2253         /* on-disk format */
2254         binfo->bi_v.bi_vblocknr = cpu_to_le64(ptr);
2255         binfo->bi_v.bi_blkoff = cpu_to_le64(key);
2256
2257         return 0;
2258 }
2259
2260 static int nilfs_btree_assign(struct nilfs_bmap *btree,
2261                               struct buffer_head **bh,
2262                               sector_t blocknr,
2263                               union nilfs_binfo *binfo)
2264 {
2265         struct nilfs_btree_path *path;
2266         struct nilfs_btree_node *node;
2267         __u64 key;
2268         int level, ret;
2269
2270         path = nilfs_btree_alloc_path();
2271         if (path == NULL)
2272                 return -ENOMEM;
2273
2274         if (buffer_nilfs_node(*bh)) {
2275                 node = (struct nilfs_btree_node *)(*bh)->b_data;
2276                 key = nilfs_btree_node_get_key(node, 0);
2277                 level = nilfs_btree_node_get_level(node);
2278         } else {
2279                 key = nilfs_bmap_data_get_key(btree, *bh);
2280                 level = NILFS_BTREE_LEVEL_DATA;
2281         }
2282
2283         ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
2284         if (ret < 0) {
2285                 WARN_ON(ret == -ENOENT);
2286                 goto out;
2287         }
2288
2289         ret = NILFS_BMAP_USE_VBN(btree) ?
2290                 nilfs_btree_assign_v(btree, path, level, bh, blocknr, binfo) :
2291                 nilfs_btree_assign_p(btree, path, level, bh, blocknr, binfo);
2292
2293  out:
2294         nilfs_btree_free_path(path);
2295
2296         return ret;
2297 }
2298
2299 static int nilfs_btree_assign_gc(struct nilfs_bmap *btree,
2300                                  struct buffer_head **bh,
2301                                  sector_t blocknr,
2302                                  union nilfs_binfo *binfo)
2303 {
2304         struct nilfs_btree_node *node;
2305         __u64 key;
2306         int ret;
2307
2308         ret = nilfs_dat_move(nilfs_bmap_get_dat(btree), (*bh)->b_blocknr,
2309                              blocknr);
2310         if (ret < 0)
2311                 return ret;
2312
2313         if (buffer_nilfs_node(*bh)) {
2314                 node = (struct nilfs_btree_node *)(*bh)->b_data;
2315                 key = nilfs_btree_node_get_key(node, 0);
2316         } else
2317                 key = nilfs_bmap_data_get_key(btree, *bh);
2318
2319         /* on-disk format */
2320         binfo->bi_v.bi_vblocknr = cpu_to_le64((*bh)->b_blocknr);
2321         binfo->bi_v.bi_blkoff = cpu_to_le64(key);
2322
2323         return 0;
2324 }
2325
2326 static int nilfs_btree_mark(struct nilfs_bmap *btree, __u64 key, int level)
2327 {
2328         struct buffer_head *bh;
2329         struct nilfs_btree_path *path;
2330         __u64 ptr;
2331         int ret;
2332
2333         path = nilfs_btree_alloc_path();
2334         if (path == NULL)
2335                 return -ENOMEM;
2336
2337         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1, 0);
2338         if (ret < 0) {
2339                 WARN_ON(ret == -ENOENT);
2340                 goto out;
2341         }
2342         ret = nilfs_btree_get_block(btree, ptr, &bh);
2343         if (ret < 0) {
2344                 WARN_ON(ret == -ENOENT);
2345                 goto out;
2346         }
2347
2348         if (!buffer_dirty(bh))
2349                 mark_buffer_dirty(bh);
2350         brelse(bh);
2351         if (!nilfs_bmap_dirty(btree))
2352                 nilfs_bmap_set_dirty(btree);
2353
2354  out:
2355         nilfs_btree_free_path(path);
2356         return ret;
2357 }
2358
2359 static const struct nilfs_bmap_operations nilfs_btree_ops = {
2360         .bop_lookup             =       nilfs_btree_lookup,
2361         .bop_lookup_contig      =       nilfs_btree_lookup_contig,
2362         .bop_insert             =       nilfs_btree_insert,
2363         .bop_delete             =       nilfs_btree_delete,
2364         .bop_clear              =       NULL,
2365
2366         .bop_propagate          =       nilfs_btree_propagate,
2367
2368         .bop_lookup_dirty_buffers =     nilfs_btree_lookup_dirty_buffers,
2369
2370         .bop_assign             =       nilfs_btree_assign,
2371         .bop_mark               =       nilfs_btree_mark,
2372
2373         .bop_seek_key           =       nilfs_btree_seek_key,
2374         .bop_last_key           =       nilfs_btree_last_key,
2375
2376         .bop_check_insert       =       NULL,
2377         .bop_check_delete       =       nilfs_btree_check_delete,
2378         .bop_gather_data        =       nilfs_btree_gather_data,
2379 };
2380
2381 static const struct nilfs_bmap_operations nilfs_btree_ops_gc = {
2382         .bop_lookup             =       NULL,
2383         .bop_lookup_contig      =       NULL,
2384         .bop_insert             =       NULL,
2385         .bop_delete             =       NULL,
2386         .bop_clear              =       NULL,
2387
2388         .bop_propagate          =       nilfs_btree_propagate_gc,
2389
2390         .bop_lookup_dirty_buffers =     nilfs_btree_lookup_dirty_buffers,
2391
2392         .bop_assign             =       nilfs_btree_assign_gc,
2393         .bop_mark               =       NULL,
2394
2395         .bop_seek_key           =       NULL,
2396         .bop_last_key           =       NULL,
2397
2398         .bop_check_insert       =       NULL,
2399         .bop_check_delete       =       NULL,
2400         .bop_gather_data        =       NULL,
2401 };
2402
2403 static void __nilfs_btree_init(struct nilfs_bmap *bmap)
2404 {
2405         bmap->b_ops = &nilfs_btree_ops;
2406         bmap->b_nchildren_per_block =
2407                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
2408 }
2409
2410 int nilfs_btree_init(struct nilfs_bmap *bmap)
2411 {
2412         int ret = 0;
2413
2414         __nilfs_btree_init(bmap);
2415
2416         if (nilfs_btree_root_broken(nilfs_btree_get_root(bmap), bmap->b_inode))
2417                 ret = -EIO;
2418         else
2419                 ret = nilfs_attach_btree_node_cache(
2420                         &NILFS_BMAP_I(bmap)->vfs_inode);
2421
2422         return ret;
2423 }
2424
2425 void nilfs_btree_init_gc(struct nilfs_bmap *bmap)
2426 {
2427         bmap->b_ops = &nilfs_btree_ops_gc;
2428         bmap->b_nchildren_per_block =
2429                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
2430 }