fs/nilfs2/btree.c

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