fs/nilfs2/btree.c

   1 /*
   2  * btree.c - NILFS B-tree.
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Written by Koji Sato <[email protected]>.
  21  */
  22
  23 #include <linux/slab.h>
  24 #include <linux/string.h>
  25 #include <linux/errno.h>
  26 #include <linux/pagevec.h>
  27 #include "nilfs.h"
  28 #include "page.h"
  29 #include "btnode.h"
  30 #include "btree.h"
  31 #include "alloc.h"
  32 #include "dat.h"
  33
  34 static void __nilfs_btree_init(struct nilfs_bmap *bmap);
  35
  36 static struct nilfs_btree_path *nilfs_btree_alloc_path(void)
  37 {
  38         struct nilfs_btree_path *path;
  39         int level = NILFS_BTREE_LEVEL_DATA;
  40
  41         path = kmem_cache_alloc(nilfs_btree_path_cache, GFP_NOFS);
  42         if (path == NULL)
  43                 goto out;
  44
  45         for (; level < NILFS_BTREE_LEVEL_MAX; level++) {
  46                 path[level].bp_bh = NULL;
  47                 path[level].bp_sib_bh = NULL;
  48                 path[level].bp_index = 0;
  49                 path[level].bp_oldreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
  50                 path[level].bp_newreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
  51                 path[level].bp_op = NULL;
  52         }
  53
  54 out:
  55         return path;
  56 }
  57
  58 static void nilfs_btree_free_path(struct nilfs_btree_path *path)
  59 {
  60         int level = NILFS_BTREE_LEVEL_DATA;
  61
  62         for (; level < NILFS_BTREE_LEVEL_MAX; level++)
  63                 brelse(path[level].bp_bh);
  64
  65         kmem_cache_free(nilfs_btree_path_cache, path);
  66 }
  67
  68 /*
  69  * B-tree node operations
  70  */
  71 static int nilfs_btree_get_new_block(const struct nilfs_bmap *btree,
  72                                      __u64 ptr, struct buffer_head **bhp)
  73 {
  74         struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;
  75         struct buffer_head *bh;
  76
  77         bh = nilfs_btnode_create_block(btnc, ptr);
  78         if (!bh)
  79                 return -ENOMEM;
  80
  81         set_buffer_nilfs_volatile(bh);
  82         *bhp = bh;
  83         return 0;
  84 }
  85
  86 static int nilfs_btree_node_get_flags(const struct nilfs_btree_node *node)
  87 {
  88         return node->bn_flags;
  89 }
  90
  91 static void
  92 nilfs_btree_node_set_flags(struct nilfs_btree_node *node, int flags)
  93 {
  94         node->bn_flags = flags;
  95 }
  96
  97 static int nilfs_btree_node_root(const struct nilfs_btree_node *node)
  98 {
  99         return nilfs_btree_node_get_flags(node) & NILFS_BTREE_NODE_ROOT;
 100 }
 101
 102 static int nilfs_btree_node_get_level(const struct nilfs_btree_node *node)
 103 {
 104         return node->bn_level;
 105 }
 106
 107 static void
 108 nilfs_btree_node_set_level(struct nilfs_btree_node *node, int level)
 109 {
 110         node->bn_level = level;
 111 }
 112
 113 static int nilfs_btree_node_get_nchildren(const struct nilfs_btree_node *node)
 114 {
 115         return le16_to_cpu(node->bn_nchildren);
 116 }
 117
 118 static void
 119 nilfs_btree_node_set_nchildren(struct nilfs_btree_node *node, int nchildren)
 120 {
 121         node->bn_nchildren = cpu_to_le16(nchildren);
 122 }
 123
 124 static int nilfs_btree_node_size(const struct nilfs_bmap *btree)
 125 {
 126         return 1 << btree->b_inode->i_blkbits;
 127 }
 128
 129 static int nilfs_btree_nchildren_per_block(const struct nilfs_bmap *btree)
 130 {
 131         return btree->b_nchildren_per_block;
 132 }
 133
 134 static __le64 *
 135 nilfs_btree_node_dkeys(const struct nilfs_btree_node *node)
 136 {
 137         return (__le64 *)((char *)(node + 1) +
 138                           (nilfs_btree_node_root(node) ?
 139                            0 : NILFS_BTREE_NODE_EXTRA_PAD_SIZE));
 140 }
 141
 142 static __le64 *
 143 nilfs_btree_node_dptrs(const struct nilfs_btree_node *node, int ncmax)
 144 {
 145         return (__le64 *)(nilfs_btree_node_dkeys(node) + ncmax);
 146 }
 147
 148 static __u64
 149 nilfs_btree_node_get_key(const struct nilfs_btree_node *node, int index)
 150 {
 151         return le64_to_cpu(*(nilfs_btree_node_dkeys(node) + index));
 152 }
 153
 154 static void
 155 nilfs_btree_node_set_key(struct nilfs_btree_node *node, int index, __u64 key)
 156 {
 157         *(nilfs_btree_node_dkeys(node) + index) = cpu_to_le64(key);
 158 }
 159
 160 static __u64
 161 nilfs_btree_node_get_ptr(const struct nilfs_btree_node *node, int index,
 162                          int ncmax)
 163 {
 164         return le64_to_cpu(*(nilfs_btree_node_dptrs(node, ncmax) + index));
 165 }
 166
 167 static void
 168 nilfs_btree_node_set_ptr(struct nilfs_btree_node *node, int index, __u64 ptr,
 169                          int ncmax)
 170 {
 171         *(nilfs_btree_node_dptrs(node, ncmax) + index) = cpu_to_le64(ptr);
 172 }
 173
 174 static void nilfs_btree_node_init(struct nilfs_btree_node *node, int flags,
 175                                   int level, int nchildren, int ncmax,
 176                                   const __u64 *keys, const __u64 *ptrs)
 177 {
 178         __le64 *dkeys;
 179         __le64 *dptrs;
 180         int i;
 181
 182         nilfs_btree_node_set_flags(node, flags);
 183         nilfs_btree_node_set_level(node, level);
 184         nilfs_btree_node_set_nchildren(node, nchildren);
 185
 186         dkeys = nilfs_btree_node_dkeys(node);
 187         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 188         for (i = 0; i < nchildren; i++) {
 189                 dkeys[i] = cpu_to_le64(keys[i]);
 190                 dptrs[i] = cpu_to_le64(ptrs[i]);
 191         }
 192 }
 193
 194 /* Assume the buffer heads corresponding to left and right are locked. */
 195 static void nilfs_btree_node_move_left(struct nilfs_btree_node *left,
 196                                        struct nilfs_btree_node *right,
 197                                        int n, int lncmax, int rncmax)
 198 {
 199         __le64 *ldkeys, *rdkeys;
 200         __le64 *ldptrs, *rdptrs;
 201         int lnchildren, rnchildren;
 202
 203         ldkeys = nilfs_btree_node_dkeys(left);
 204         ldptrs = nilfs_btree_node_dptrs(left, lncmax);
 205         lnchildren = nilfs_btree_node_get_nchildren(left);
 206
 207         rdkeys = nilfs_btree_node_dkeys(right);
 208         rdptrs = nilfs_btree_node_dptrs(right, rncmax);
 209         rnchildren = nilfs_btree_node_get_nchildren(right);
 210
 211         memcpy(ldkeys + lnchildren, rdkeys, n * sizeof(*rdkeys));
 212         memcpy(ldptrs + lnchildren, rdptrs, n * sizeof(*rdptrs));
 213         memmove(rdkeys, rdkeys + n, (rnchildren - n) * sizeof(*rdkeys));
 214         memmove(rdptrs, rdptrs + n, (rnchildren - n) * sizeof(*rdptrs));
 215
 216         lnchildren += n;
 217         rnchildren -= n;
 218         nilfs_btree_node_set_nchildren(left, lnchildren);
 219         nilfs_btree_node_set_nchildren(right, rnchildren);
 220 }
 221
 222 /* Assume that the buffer heads corresponding to left and right are locked. */
 223 static void nilfs_btree_node_move_right(struct nilfs_btree_node *left,
 224                                         struct nilfs_btree_node *right,
 225                                         int n, int lncmax, int rncmax)
 226 {
 227         __le64 *ldkeys, *rdkeys;
 228         __le64 *ldptrs, *rdptrs;
 229         int lnchildren, rnchildren;
 230
 231         ldkeys = nilfs_btree_node_dkeys(left);
 232         ldptrs = nilfs_btree_node_dptrs(left, lncmax);
 233         lnchildren = nilfs_btree_node_get_nchildren(left);
 234
 235         rdkeys = nilfs_btree_node_dkeys(right);
 236         rdptrs = nilfs_btree_node_dptrs(right, rncmax);
 237         rnchildren = nilfs_btree_node_get_nchildren(right);
 238
 239         memmove(rdkeys + n, rdkeys, rnchildren * sizeof(*rdkeys));
 240         memmove(rdptrs + n, rdptrs, rnchildren * sizeof(*rdptrs));
 241         memcpy(rdkeys, ldkeys + lnchildren - n, n * sizeof(*rdkeys));
 242         memcpy(rdptrs, ldptrs + lnchildren - n, n * sizeof(*rdptrs));
 243
 244         lnchildren -= n;
 245         rnchildren += n;
 246         nilfs_btree_node_set_nchildren(left, lnchildren);
 247         nilfs_btree_node_set_nchildren(right, rnchildren);
 248 }
 249
 250 /* Assume that the buffer head corresponding to node is locked. */
 251 static void nilfs_btree_node_insert(struct nilfs_btree_node *node, int index,
 252                                     __u64 key, __u64 ptr, int ncmax)
 253 {
 254         __le64 *dkeys;
 255         __le64 *dptrs;
 256         int nchildren;
 257
 258         dkeys = nilfs_btree_node_dkeys(node);
 259         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 260         nchildren = nilfs_btree_node_get_nchildren(node);
 261         if (index < nchildren) {
 262                 memmove(dkeys + index + 1, dkeys + index,
 263                         (nchildren - index) * sizeof(*dkeys));
 264                 memmove(dptrs + index + 1, dptrs + index,
 265                         (nchildren - index) * sizeof(*dptrs));
 266         }
 267         dkeys[index] = cpu_to_le64(key);
 268         dptrs[index] = cpu_to_le64(ptr);
 269         nchildren++;
 270         nilfs_btree_node_set_nchildren(node, nchildren);
 271 }
 272
 273 /* Assume that the buffer head corresponding to node is locked. */
 274 static void nilfs_btree_node_delete(struct nilfs_btree_node *node, int index,
 275                                     __u64 *keyp, __u64 *ptrp, int ncmax)
 276 {
 277         __u64 key;
 278         __u64 ptr;
 279         __le64 *dkeys;
 280         __le64 *dptrs;
 281         int nchildren;
 282
 283         dkeys = nilfs_btree_node_dkeys(node);
 284         dptrs = nilfs_btree_node_dptrs(node, ncmax);
 285         key = le64_to_cpu(dkeys[index]);
 286         ptr = le64_to_cpu(dptrs[index]);
 287         nchildren = nilfs_btree_node_get_nchildren(node);
 288         if (keyp != NULL)
 289                 *keyp = key;
 290         if (ptrp != NULL)
 291                 *ptrp = ptr;
 292
 293         if (index < nchildren - 1) {
 294                 memmove(dkeys + index, dkeys + index + 1,
 295                         (nchildren - index - 1) * sizeof(*dkeys));
 296                 memmove(dptrs + index, dptrs + index + 1,
 297                         (nchildren - index - 1) * sizeof(*dptrs));
 298         }
 299         nchildren--;
 300         nilfs_btree_node_set_nchildren(node, nchildren);
 301 }
 302
 303 static int nilfs_btree_node_lookup(const struct nilfs_btree_node *node,
 304                                    __u64 key, int *indexp)
 305 {
 306         __u64 nkey;
 307         int index, low, high, s;
 308
 309         /* binary search */
 310         low = 0;
 311         high = nilfs_btree_node_get_nchildren(node) - 1;
 312         index = 0;
 313         s = 0;
 314         while (low <= high) {
 315                 index = (low + high) / 2;
 316                 nkey = nilfs_btree_node_get_key(node, index);
 317                 if (nkey == key) {
 318                         s = 0;
 319                         goto out;
 320                 } else if (nkey < key) {
 321                         low = index + 1;
 322                         s = -1;
 323                 } else {
 324                         high = index - 1;
 325                         s = 1;
 326                 }
 327         }
 328
 329         /* adjust index */
 330         if (nilfs_btree_node_get_level(node) > NILFS_BTREE_LEVEL_NODE_MIN) {
 331                 if (s > 0 && index > 0)
 332                         index--;
 333         } else if (s < 0)
 334                 index++;
 335
 336  out:
 337         *indexp = index;
 338
 339         return s == 0;
 340 }
 341
 342 /**
 343  * nilfs_btree_node_broken - verify consistency of btree node
 344  * @node: btree node block to be examined
 345  * @size: node size (in bytes)
 346  * @blocknr: block number
 347  *
 348  * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
 349  */
 350 static int nilfs_btree_node_broken(const struct nilfs_btree_node *node,
 351                                    size_t size, sector_t blocknr)
 352 {
 353         int level, flags, nchildren;
 354         int ret = 0;
 355
 356         level = nilfs_btree_node_get_level(node);
 357         flags = nilfs_btree_node_get_flags(node);
 358         nchildren = nilfs_btree_node_get_nchildren(node);
 359
 360         if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
 361                      level >= NILFS_BTREE_LEVEL_MAX ||
 362                      (flags & NILFS_BTREE_NODE_ROOT) ||
 363                      nchildren < 0 ||
 364                      nchildren > NILFS_BTREE_NODE_NCHILDREN_MAX(size))) {
 365                 printk(KERN_CRIT "NILFS: bad btree node (blocknr=%llu): "
 366                        "level = %d, flags = 0x%x, nchildren = %d\n",
 367                        (unsigned long long)blocknr, level, flags, nchildren);
 368                 ret = 1;
 369         }
 370         return ret;
 371 }
 372
 373 /**
 374  * nilfs_btree_root_broken - verify consistency of btree root node
 375  * @node: btree root node to be examined
 376  * @ino: inode number
 377  *
 378  * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
 379  */
 380 static int nilfs_btree_root_broken(const struct nilfs_btree_node *node,
 381                                    unsigned long ino)
 382 {
 383         int level, flags, nchildren;
 384         int ret = 0;
 385
 386         level = nilfs_btree_node_get_level(node);
 387         flags = nilfs_btree_node_get_flags(node);
 388         nchildren = nilfs_btree_node_get_nchildren(node);
 389
 390         if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
 391                      level > NILFS_BTREE_LEVEL_MAX ||
 392                      nchildren < 0 ||
 393                      nchildren > NILFS_BTREE_ROOT_NCHILDREN_MAX)) {
 394                 pr_crit("NILFS: bad btree root (inode number=%lu): level = %d, flags = 0x%x, nchildren = %d\n",
 395                         ino, level, flags, nchildren);
 396                 ret = 1;
 397         }
 398         return ret;
 399 }
 400
 401 int nilfs_btree_broken_node_block(struct buffer_head *bh)
 402 {
 403         int ret;
 404
 405         if (buffer_nilfs_checked(bh))
 406                 return 0;
 407
 408         ret = nilfs_btree_node_broken((struct nilfs_btree_node *)bh->b_data,
 409                                        bh->b_size, bh->b_blocknr);
 410         if (likely(!ret))
 411                 set_buffer_nilfs_checked(bh);
 412         return ret;
 413 }
 414
 415 static struct nilfs_btree_node *
 416 nilfs_btree_get_root(const struct nilfs_bmap *btree)
 417 {
 418         return (struct nilfs_btree_node *)btree->b_u.u_data;
 419 }
 420
 421 static struct nilfs_btree_node *
 422 nilfs_btree_get_nonroot_node(const struct nilfs_btree_path *path, int level)
 423 {
 424         return (struct nilfs_btree_node *)path[level].bp_bh->b_data;
 425 }
 426
 427 static struct nilfs_btree_node *
 428 nilfs_btree_get_sib_node(const struct nilfs_btree_path *path, int level)
 429 {
 430         return (struct nilfs_btree_node *)path[level].bp_sib_bh->b_data;
 431 }
 432
 433 static int nilfs_btree_height(const struct nilfs_bmap *btree)
 434 {
 435         return nilfs_btree_node_get_level(nilfs_btree_get_root(btree)) + 1;
 436 }
 437
 438 static struct nilfs_btree_node *
 439 nilfs_btree_get_node(const struct nilfs_bmap *btree,
 440                      const struct nilfs_btree_path *path,
 441                      int level, int *ncmaxp)
 442 {
 443         struct nilfs_btree_node *node;
 444
 445         if (level == nilfs_btree_height(btree) - 1) {
 446                 node = nilfs_btree_get_root(btree);
 447                 *ncmaxp = NILFS_BTREE_ROOT_NCHILDREN_MAX;
 448         } else {
 449                 node = nilfs_btree_get_nonroot_node(path, level);
 450                 *ncmaxp = nilfs_btree_nchildren_per_block(btree);
 451         }
 452         return node;
 453 }
 454
 455 static int
 456 nilfs_btree_bad_node(struct nilfs_btree_node *node, int level)
 457 {
 458         if (unlikely(nilfs_btree_node_get_level(node) != level)) {
 459                 dump_stack();
 460                 printk(KERN_CRIT "NILFS: btree level mismatch: %d != %d\n",
 461                        nilfs_btree_node_get_level(node), level);
 462                 return 1;
 463         }
 464         return 0;
 465 }
 466
 467 struct nilfs_btree_readahead_info {
 468         struct nilfs_btree_node *node;  /* parent node */
 469         int max_ra_blocks;              /* max nof blocks to read ahead */
 470         int index;                      /* current index on the parent node */
 471         int ncmax;                      /* nof children in the parent node */
 472 };
 473
 474 static int __nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
 475                                    struct buffer_head **bhp,
 476                                    const struct nilfs_btree_readahead_info *ra)
 477 {
 478         struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;
 479         struct buffer_head *bh, *ra_bh;
 480         sector_t submit_ptr = 0;
 481         int ret;
 482
 483         ret = nilfs_btnode_submit_block(btnc, ptr, 0, READ, &bh, &submit_ptr);
 484         if (ret) {
 485                 if (ret != -EEXIST)
 486                         return ret;
 487                 goto out_check;
 488         }
 489
 490         if (ra) {
 491                 int i, n;
 492                 __u64 ptr2;
 493
 494                 /* read ahead sibling nodes */
 495                 for (n = ra->max_ra_blocks, i = ra->index + 1;
 496                      n > 0 && i < ra->ncmax; n--, i++) {
 497                         ptr2 = nilfs_btree_node_get_ptr(ra->node, i, ra->ncmax);
 498
 499                         ret = nilfs_btnode_submit_block(btnc, ptr2, 0, READA,
 500                                                         &ra_bh, &submit_ptr);
 501                         if (likely(!ret || ret == -EEXIST))
 502                                 brelse(ra_bh);
 503                         else if (ret != -EBUSY)
 504                                 break;
 505                         if (!buffer_locked(bh))
 506                                 goto out_no_wait;
 507                 }
 508         }
 509
 510         wait_on_buffer(bh);
 511
 512  out_no_wait:
 513         if (!buffer_uptodate(bh)) {
 514                 brelse(bh);
 515                 return -EIO;
 516         }
 517
 518  out_check:
 519         if (nilfs_btree_broken_node_block(bh)) {
 520                 clear_buffer_uptodate(bh);
 521                 brelse(bh);
 522                 return -EINVAL;
 523         }
 524
 525         *bhp = bh;
 526         return 0;
 527 }
 528
 529 static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
 530                                    struct buffer_head **bhp)
 531 {
 532         return __nilfs_btree_get_block(btree, ptr, bhp, NULL);
 533 }
 534
 535 static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree,
 536                                  struct nilfs_btree_path *path,
 537                                  __u64 key, __u64 *ptrp, int minlevel,
 538                                  int readahead)
 539 {
 540         struct nilfs_btree_node *node;
 541         struct nilfs_btree_readahead_info p, *ra;
 542         __u64 ptr;
 543         int level, index, found, ncmax, ret;
 544
 545         node = nilfs_btree_get_root(btree);
 546         level = nilfs_btree_node_get_level(node);
 547         if (level < minlevel || nilfs_btree_node_get_nchildren(node) <= 0)
 548                 return -ENOENT;
 549
 550         found = nilfs_btree_node_lookup(node, key, &index);
 551         ptr = nilfs_btree_node_get_ptr(node, index,
 552                                        NILFS_BTREE_ROOT_NCHILDREN_MAX);
 553         path[level].bp_bh = NULL;
 554         path[level].bp_index = index;
 555
 556         ncmax = nilfs_btree_nchildren_per_block(btree);
 557
 558         while (--level >= minlevel) {
 559                 ra = NULL;
 560                 if (level == NILFS_BTREE_LEVEL_NODE_MIN && readahead) {
 561                         p.node = nilfs_btree_get_node(btree, path, level + 1,
 562                                                       &p.ncmax);
 563                         p.index = index;
 564                         p.max_ra_blocks = 7;
 565                         ra = &p;
 566                 }
 567                 ret = __nilfs_btree_get_block(btree, ptr, &path[level].bp_bh,
 568                                               ra);
 569                 if (ret < 0)
 570                         return ret;
 571
 572                 node = nilfs_btree_get_nonroot_node(path, level);
 573                 if (nilfs_btree_bad_node(node, level))
 574                         return -EINVAL;
 575                 if (!found)
 576                         found = nilfs_btree_node_lookup(node, key, &index);
 577                 else
 578                         index = 0;
 579                 if (index < ncmax) {
 580                         ptr = nilfs_btree_node_get_ptr(node, index, ncmax);
 581                 } else {
 582                         WARN_ON(found || level != NILFS_BTREE_LEVEL_NODE_MIN);
 583                         /* insert */
 584                         ptr = NILFS_BMAP_INVALID_PTR;
 585                 }
 586                 path[level].bp_index = index;
 587         }
 588         if (!found)
 589                 return -ENOENT;
 590
 591         if (ptrp != NULL)
 592                 *ptrp = ptr;
 593
 594         return 0;
 595 }
 596
 597 static int nilfs_btree_do_lookup_last(const struct nilfs_bmap *btree,
 598                                       struct nilfs_btree_path *path,
 599                                       __u64 *keyp, __u64 *ptrp)
 600 {
 601         struct nilfs_btree_node *node;
 602         __u64 ptr;
 603         int index, level, ncmax, ret;
 604
 605         node = nilfs_btree_get_root(btree);
 606         index = nilfs_btree_node_get_nchildren(node) - 1;
 607         if (index < 0)
 608                 return -ENOENT;
 609         level = nilfs_btree_node_get_level(node);
 610         ptr = nilfs_btree_node_get_ptr(node, index,
 611                                        NILFS_BTREE_ROOT_NCHILDREN_MAX);
 612         path[level].bp_bh = NULL;
 613         path[level].bp_index = index;
 614         ncmax = nilfs_btree_nchildren_per_block(btree);
 615
 616         for (level--; level > 0; level--) {
 617                 ret = nilfs_btree_get_block(btree, ptr, &path[level].bp_bh);
 618                 if (ret < 0)
 619                         return ret;
 620                 node = nilfs_btree_get_nonroot_node(path, level);
 621                 if (nilfs_btree_bad_node(node, level))
 622                         return -EINVAL;
 623                 index = nilfs_btree_node_get_nchildren(node) - 1;
 624                 ptr = nilfs_btree_node_get_ptr(node, index, ncmax);
 625                 path[level].bp_index = index;
 626         }
 627
 628         if (keyp != NULL)
 629                 *keyp = nilfs_btree_node_get_key(node, index);
 630         if (ptrp != NULL)
 631                 *ptrp = ptr;
 632
 633         return 0;
 634 }
 635
 636 /**
 637  * nilfs_btree_get_next_key - get next valid key from btree path array
 638  * @btree: bmap struct of btree
 639  * @path: array of nilfs_btree_path struct
 640  * @minlevel: start level
 641  * @nextkey: place to store the next valid key
 642  *
 643  * Return Value: If a next key was found, 0 is returned. Otherwise,
 644  * -ENOENT is returned.
 645  */
 646 static int nilfs_btree_get_next_key(const struct nilfs_bmap *btree,
 647                                     const struct nilfs_btree_path *path,
 648                                     int minlevel, __u64 *nextkey)
 649 {
 650         struct nilfs_btree_node *node;
 651         int maxlevel = nilfs_btree_height(btree) - 1;
 652         int index, next_adj, level;
 653
 654         /* Next index is already set to bp_index for leaf nodes. */
 655         next_adj = 0;
 656         for (level = minlevel; level <= maxlevel; level++) {
 657                 if (level == maxlevel)
 658                         node = nilfs_btree_get_root(btree);
 659                 else
 660                         node = nilfs_btree_get_nonroot_node(path, level);
 661
 662                 index = path[level].bp_index + next_adj;
 663                 if (index < nilfs_btree_node_get_nchildren(node)) {
 664                         /* Next key is in this node */
 665                         *nextkey = nilfs_btree_node_get_key(node, index);
 666                         return 0;
 667                 }
 668                 /* For non-leaf nodes, next index is stored at bp_index + 1. */
 669                 next_adj = 1;
 670         }
 671         return -ENOENT;
 672 }
 673
 674 static int nilfs_btree_lookup(const struct nilfs_bmap *btree,
 675                               __u64 key, int level, __u64 *ptrp)
 676 {
 677         struct nilfs_btree_path *path;
 678         int ret;
 679
 680         path = nilfs_btree_alloc_path();
 681         if (path == NULL)
 682                 return -ENOMEM;
 683
 684         ret = nilfs_btree_do_lookup(btree, path, key, ptrp, level, 0);
 685
 686         nilfs_btree_free_path(path);
 687
 688         return ret;
 689 }
 690
 691 static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree,
 692                                      __u64 key, __u64 *ptrp, unsigned maxblocks)
 693 {
 694         struct nilfs_btree_path *path;
 695         struct nilfs_btree_node *node;
 696         struct inode *dat = NULL;
 697         __u64 ptr, ptr2;
 698         sector_t blocknr;
 699         int level = NILFS_BTREE_LEVEL_NODE_MIN;
 700         int ret, cnt, index, maxlevel, ncmax;
 701         struct nilfs_btree_readahead_info p;
 702
 703         path = nilfs_btree_alloc_path();
 704         if (path == NULL)
 705                 return -ENOMEM;
 706
 707         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level, 1);
 708         if (ret < 0)
 709                 goto out;
 710
 711         if (NILFS_BMAP_USE_VBN(btree)) {
 712                 dat = nilfs_bmap_get_dat(btree);
 713                 ret = nilfs_dat_translate(dat, ptr, &blocknr);
 714                 if (ret < 0)
 715                         goto out;
 716                 ptr = blocknr;
 717         }
 718         cnt = 1;
 719         if (cnt == maxblocks)
 720                 goto end;
 721
 722         maxlevel = nilfs_btree_height(btree) - 1;
 723         node = nilfs_btree_get_node(btree, path, level, &ncmax);
 724         index = path[level].bp_index + 1;
 725         for (;;) {
 726                 while (index < nilfs_btree_node_get_nchildren(node)) {
 727                         if (nilfs_btree_node_get_key(node, index) !=
 728                             key + cnt)
 729                                 goto end;
 730                         ptr2 = nilfs_btree_node_get_ptr(node, index, ncmax);
 731                         if (dat) {
 732                                 ret = nilfs_dat_translate(dat, ptr2, &blocknr);
 733                                 if (ret < 0)
 734                                         goto out;
 735                                 ptr2 = blocknr;
 736                         }
 737                         if (ptr2 != ptr + cnt || ++cnt == maxblocks)
 738                                 goto end;
 739                         index++;
 740                         continue;
 741                 }
 742                 if (level == maxlevel)
 743                         break;
 744
 745                 /* look-up right sibling node */
 746                 p.node = nilfs_btree_get_node(btree, path, level + 1, &p.ncmax);
 747                 p.index = path[level + 1].bp_index + 1;
 748                 p.max_ra_blocks = 7;
 749                 if (p.index >= nilfs_btree_node_get_nchildren(p.node) ||
 750                     nilfs_btree_node_get_key(p.node, p.index) != key + cnt)
 751                         break;
 752                 ptr2 = nilfs_btree_node_get_ptr(p.node, p.index, p.ncmax);
 753                 path[level + 1].bp_index = p.index;
 754
 755                 brelse(path[level].bp_bh);
 756                 path[level].bp_bh = NULL;
 757
 758                 ret = __nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh,
 759                                               &p);
 760                 if (ret < 0)
 761                         goto out;
 762                 node = nilfs_btree_get_nonroot_node(path, level);
 763                 ncmax = nilfs_btree_nchildren_per_block(btree);
 764                 index = 0;
 765                 path[level].bp_index = index;
 766         }
 767  end:
 768         *ptrp = ptr;
 769         ret = cnt;
 770  out:
 771         nilfs_btree_free_path(path);
 772         return ret;
 773 }
 774
 775 static void nilfs_btree_promote_key(struct nilfs_bmap *btree,
 776                                     struct nilfs_btree_path *path,
 777                                     int level, __u64 key)
 778 {
 779         if (level < nilfs_btree_height(btree) - 1) {
 780                 do {
 781                         nilfs_btree_node_set_key(
 782                                 nilfs_btree_get_nonroot_node(path, level),
 783                                 path[level].bp_index, key);
 784                         if (!buffer_dirty(path[level].bp_bh))
 785                                 mark_buffer_dirty(path[level].bp_bh);
 786                 } while ((path[level].bp_index == 0) &&
 787                          (++level < nilfs_btree_height(btree) - 1));
 788         }
 789
 790         /* root */
 791         if (level == nilfs_btree_height(btree) - 1) {
 792                 nilfs_btree_node_set_key(nilfs_btree_get_root(btree),
 793                                          path[level].bp_index, key);
 794         }
 795 }
 796
 797 static void nilfs_btree_do_insert(struct nilfs_bmap *btree,
 798                                   struct nilfs_btree_path *path,
 799                                   int level, __u64 *keyp, __u64 *ptrp)
 800 {
 801         struct nilfs_btree_node *node;
 802         int ncblk;
 803
 804         if (level < nilfs_btree_height(btree) - 1) {
 805                 node = nilfs_btree_get_nonroot_node(path, level);
 806                 ncblk = nilfs_btree_nchildren_per_block(btree);
 807                 nilfs_btree_node_insert(node, path[level].bp_index,
 808                                         *keyp, *ptrp, ncblk);
 809                 if (!buffer_dirty(path[level].bp_bh))
 810                         mark_buffer_dirty(path[level].bp_bh);
 811
 812                 if (path[level].bp_index == 0)
 813                         nilfs_btree_promote_key(btree, path, level + 1,
 814                                                 nilfs_btree_node_get_key(node,
 815                                                                          0));
 816         } else {
 817                 node = nilfs_btree_get_root(btree);
 818                 nilfs_btree_node_insert(node, path[level].bp_index,
 819                                         *keyp, *ptrp,
 820                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
 821         }
 822 }
 823
 824 static void nilfs_btree_carry_left(struct nilfs_bmap *btree,
 825                                    struct nilfs_btree_path *path,
 826                                    int level, __u64 *keyp, __u64 *ptrp)
 827 {
 828         struct nilfs_btree_node *node, *left;
 829         int nchildren, lnchildren, n, move, ncblk;
 830
 831         node = nilfs_btree_get_nonroot_node(path, level);
 832         left = nilfs_btree_get_sib_node(path, level);
 833         nchildren = nilfs_btree_node_get_nchildren(node);
 834         lnchildren = nilfs_btree_node_get_nchildren(left);
 835         ncblk = nilfs_btree_nchildren_per_block(btree);
 836         move = 0;
 837
 838         n = (nchildren + lnchildren + 1) / 2 - lnchildren;
 839         if (n > path[level].bp_index) {
 840                 /* move insert point */
 841                 n--;
 842                 move = 1;
 843         }
 844
 845         nilfs_btree_node_move_left(left, node, n, ncblk, ncblk);
 846
 847         if (!buffer_dirty(path[level].bp_bh))
 848                 mark_buffer_dirty(path[level].bp_bh);
 849         if (!buffer_dirty(path[level].bp_sib_bh))
 850                 mark_buffer_dirty(path[level].bp_sib_bh);
 851
 852         nilfs_btree_promote_key(btree, path, level + 1,
 853                                 nilfs_btree_node_get_key(node, 0));
 854
 855         if (move) {
 856                 brelse(path[level].bp_bh);
 857                 path[level].bp_bh = path[level].bp_sib_bh;
 858                 path[level].bp_sib_bh = NULL;
 859                 path[level].bp_index += lnchildren;
 860                 path[level + 1].bp_index--;
 861         } else {
 862                 brelse(path[level].bp_sib_bh);
 863                 path[level].bp_sib_bh = NULL;
 864                 path[level].bp_index -= n;
 865         }
 866
 867         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 868 }
 869
 870 static void nilfs_btree_carry_right(struct nilfs_bmap *btree,
 871                                     struct nilfs_btree_path *path,
 872                                     int level, __u64 *keyp, __u64 *ptrp)
 873 {
 874         struct nilfs_btree_node *node, *right;
 875         int nchildren, rnchildren, n, move, ncblk;
 876
 877         node = nilfs_btree_get_nonroot_node(path, level);
 878         right = nilfs_btree_get_sib_node(path, level);
 879         nchildren = nilfs_btree_node_get_nchildren(node);
 880         rnchildren = nilfs_btree_node_get_nchildren(right);
 881         ncblk = nilfs_btree_nchildren_per_block(btree);
 882         move = 0;
 883
 884         n = (nchildren + rnchildren + 1) / 2 - rnchildren;
 885         if (n > nchildren - path[level].bp_index) {
 886                 /* move insert point */
 887                 n--;
 888                 move = 1;
 889         }
 890
 891         nilfs_btree_node_move_right(node, right, n, ncblk, ncblk);
 892
 893         if (!buffer_dirty(path[level].bp_bh))
 894                 mark_buffer_dirty(path[level].bp_bh);
 895         if (!buffer_dirty(path[level].bp_sib_bh))
 896                 mark_buffer_dirty(path[level].bp_sib_bh);
 897
 898         path[level + 1].bp_index++;
 899         nilfs_btree_promote_key(btree, path, level + 1,
 900                                 nilfs_btree_node_get_key(right, 0));
 901         path[level + 1].bp_index--;
 902
 903         if (move) {
 904                 brelse(path[level].bp_bh);
 905                 path[level].bp_bh = path[level].bp_sib_bh;
 906                 path[level].bp_sib_bh = NULL;
 907                 path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
 908                 path[level + 1].bp_index++;
 909         } else {
 910                 brelse(path[level].bp_sib_bh);
 911                 path[level].bp_sib_bh = NULL;
 912         }
 913
 914         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 915 }
 916
 917 static void nilfs_btree_split(struct nilfs_bmap *btree,
 918                               struct nilfs_btree_path *path,
 919                               int level, __u64 *keyp, __u64 *ptrp)
 920 {
 921         struct nilfs_btree_node *node, *right;
 922         __u64 newkey;
 923         __u64 newptr;
 924         int nchildren, n, move, ncblk;
 925
 926         node = nilfs_btree_get_nonroot_node(path, level);
 927         right = nilfs_btree_get_sib_node(path, level);
 928         nchildren = nilfs_btree_node_get_nchildren(node);
 929         ncblk = nilfs_btree_nchildren_per_block(btree);
 930         move = 0;
 931
 932         n = (nchildren + 1) / 2;
 933         if (n > nchildren - path[level].bp_index) {
 934                 n--;
 935                 move = 1;
 936         }
 937
 938         nilfs_btree_node_move_right(node, right, n, ncblk, ncblk);
 939
 940         if (!buffer_dirty(path[level].bp_bh))
 941                 mark_buffer_dirty(path[level].bp_bh);
 942         if (!buffer_dirty(path[level].bp_sib_bh))
 943                 mark_buffer_dirty(path[level].bp_sib_bh);
 944
 945         newkey = nilfs_btree_node_get_key(right, 0);
 946         newptr = path[level].bp_newreq.bpr_ptr;
 947
 948         if (move) {
 949                 path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
 950                 nilfs_btree_node_insert(right, path[level].bp_index,
 951                                         *keyp, *ptrp, ncblk);
 952
 953                 *keyp = nilfs_btree_node_get_key(right, 0);
 954                 *ptrp = path[level].bp_newreq.bpr_ptr;
 955
 956                 brelse(path[level].bp_bh);
 957                 path[level].bp_bh = path[level].bp_sib_bh;
 958                 path[level].bp_sib_bh = NULL;
 959         } else {
 960                 nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 961
 962                 *keyp = nilfs_btree_node_get_key(right, 0);
 963                 *ptrp = path[level].bp_newreq.bpr_ptr;
 964
 965                 brelse(path[level].bp_sib_bh);
 966                 path[level].bp_sib_bh = NULL;
 967         }
 968
 969         path[level + 1].bp_index++;
 970 }
 971
 972 static void nilfs_btree_grow(struct nilfs_bmap *btree,
 973                              struct nilfs_btree_path *path,
 974                              int level, __u64 *keyp, __u64 *ptrp)
 975 {
 976         struct nilfs_btree_node *root, *child;
 977         int n, ncblk;
 978
 979         root = nilfs_btree_get_root(btree);
 980         child = nilfs_btree_get_sib_node(path, level);
 981         ncblk = nilfs_btree_nchildren_per_block(btree);
 982
 983         n = nilfs_btree_node_get_nchildren(root);
 984
 985         nilfs_btree_node_move_right(root, child, n,
 986                                     NILFS_BTREE_ROOT_NCHILDREN_MAX, ncblk);
 987         nilfs_btree_node_set_level(root, level + 1);
 988
 989         if (!buffer_dirty(path[level].bp_sib_bh))
 990                 mark_buffer_dirty(path[level].bp_sib_bh);
 991
 992         path[level].bp_bh = path[level].bp_sib_bh;
 993         path[level].bp_sib_bh = NULL;
 994
 995         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
 996
 997         *keyp = nilfs_btree_node_get_key(child, 0);
 998         *ptrp = path[level].bp_newreq.bpr_ptr;
 999 }
1000
1001 static __u64 nilfs_btree_find_near(const struct nilfs_bmap *btree,
1002                                    const struct nilfs_btree_path *path)
1003 {
1004         struct nilfs_btree_node *node;
1005         int level, ncmax;
1006
1007         if (path == NULL)
1008                 return NILFS_BMAP_INVALID_PTR;
1009
1010         /* left sibling */
1011         level = NILFS_BTREE_LEVEL_NODE_MIN;
1012         if (path[level].bp_index > 0) {
1013                 node = nilfs_btree_get_node(btree, path, level, &ncmax);
1014                 return nilfs_btree_node_get_ptr(node,
1015                                                 path[level].bp_index - 1,
1016                                                 ncmax);
1017         }
1018
1019         /* parent */
1020         level = NILFS_BTREE_LEVEL_NODE_MIN + 1;
1021         if (level <= nilfs_btree_height(btree) - 1) {
1022                 node = nilfs_btree_get_node(btree, path, level, &ncmax);
1023                 return nilfs_btree_node_get_ptr(node, path[level].bp_index,
1024                                                 ncmax);
1025         }
1026
1027         return NILFS_BMAP_INVALID_PTR;
1028 }
1029
1030 static __u64 nilfs_btree_find_target_v(const struct nilfs_bmap *btree,
1031                                        const struct nilfs_btree_path *path,
1032                                        __u64 key)
1033 {
1034         __u64 ptr;
1035
1036         ptr = nilfs_bmap_find_target_seq(btree, key);
1037         if (ptr != NILFS_BMAP_INVALID_PTR)
1038                 /* sequential access */
1039                 return ptr;
1040         else {
1041                 ptr = nilfs_btree_find_near(btree, path);
1042                 if (ptr != NILFS_BMAP_INVALID_PTR)
1043                         /* near */
1044                         return ptr;
1045         }
1046         /* block group */
1047         return nilfs_bmap_find_target_in_group(btree);
1048 }
1049
1050 static int nilfs_btree_prepare_insert(struct nilfs_bmap *btree,
1051                                       struct nilfs_btree_path *path,
1052                                       int *levelp, __u64 key, __u64 ptr,
1053                                       struct nilfs_bmap_stats *stats)
1054 {
1055         struct buffer_head *bh;
1056         struct nilfs_btree_node *node, *parent, *sib;
1057         __u64 sibptr;
1058         int pindex, level, ncmax, ncblk, ret;
1059         struct inode *dat = NULL;
1060
1061         stats->bs_nblocks = 0;
1062         level = NILFS_BTREE_LEVEL_DATA;
1063
1064         /* allocate a new ptr for data block */
1065         if (NILFS_BMAP_USE_VBN(btree)) {
1066                 path[level].bp_newreq.bpr_ptr =
1067                         nilfs_btree_find_target_v(btree, path, key);
1068                 dat = nilfs_bmap_get_dat(btree);
1069         }
1070
1071         ret = nilfs_bmap_prepare_alloc_ptr(btree, &path[level].bp_newreq, dat);
1072         if (ret < 0)
1073                 goto err_out_data;
1074
1075         ncblk = nilfs_btree_nchildren_per_block(btree);
1076
1077         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
1078              level < nilfs_btree_height(btree) - 1;
1079              level++) {
1080                 node = nilfs_btree_get_nonroot_node(path, level);
1081                 if (nilfs_btree_node_get_nchildren(node) < ncblk) {
1082                         path[level].bp_op = nilfs_btree_do_insert;
1083                         stats->bs_nblocks++;
1084                         goto out;
1085                 }
1086
1087                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1088                 pindex = path[level + 1].bp_index;
1089
1090                 /* left sibling */
1091                 if (pindex > 0) {
1092                         sibptr = nilfs_btree_node_get_ptr(parent, pindex - 1,
1093                                                           ncmax);
1094                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1095                         if (ret < 0)
1096                                 goto err_out_child_node;
1097                         sib = (struct nilfs_btree_node *)bh->b_data;
1098                         if (nilfs_btree_node_get_nchildren(sib) < ncblk) {
1099                                 path[level].bp_sib_bh = bh;
1100                                 path[level].bp_op = nilfs_btree_carry_left;
1101                                 stats->bs_nblocks++;
1102                                 goto out;
1103                         } else {
1104                                 brelse(bh);
1105                         }
1106                 }
1107
1108                 /* right sibling */
1109                 if (pindex < nilfs_btree_node_get_nchildren(parent) - 1) {
1110                         sibptr = nilfs_btree_node_get_ptr(parent, pindex + 1,
1111                                                           ncmax);
1112                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1113                         if (ret < 0)
1114                                 goto err_out_child_node;
1115                         sib = (struct nilfs_btree_node *)bh->b_data;
1116                         if (nilfs_btree_node_get_nchildren(sib) < ncblk) {
1117                                 path[level].bp_sib_bh = bh;
1118                                 path[level].bp_op = nilfs_btree_carry_right;
1119                                 stats->bs_nblocks++;
1120                                 goto out;
1121                         } else {
1122                                 brelse(bh);
1123                         }
1124                 }
1125
1126                 /* split */
1127                 path[level].bp_newreq.bpr_ptr =
1128                         path[level - 1].bp_newreq.bpr_ptr + 1;
1129                 ret = nilfs_bmap_prepare_alloc_ptr(btree,
1130                                                    &path[level].bp_newreq, dat);
1131                 if (ret < 0)
1132                         goto err_out_child_node;
1133                 ret = nilfs_btree_get_new_block(btree,
1134                                                 path[level].bp_newreq.bpr_ptr,
1135                                                 &bh);
1136                 if (ret < 0)
1137                         goto err_out_curr_node;
1138
1139                 stats->bs_nblocks++;
1140
1141                 sib = (struct nilfs_btree_node *)bh->b_data;
1142                 nilfs_btree_node_init(sib, 0, level, 0, ncblk, NULL, NULL);
1143                 path[level].bp_sib_bh = bh;
1144                 path[level].bp_op = nilfs_btree_split;
1145         }
1146
1147         /* root */
1148         node = nilfs_btree_get_root(btree);
1149         if (nilfs_btree_node_get_nchildren(node) <
1150             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1151                 path[level].bp_op = nilfs_btree_do_insert;
1152                 stats->bs_nblocks++;
1153                 goto out;
1154         }
1155
1156         /* grow */
1157         path[level].bp_newreq.bpr_ptr = path[level - 1].bp_newreq.bpr_ptr + 1;
1158         ret = nilfs_bmap_prepare_alloc_ptr(btree, &path[level].bp_newreq, dat);
1159         if (ret < 0)
1160                 goto err_out_child_node;
1161         ret = nilfs_btree_get_new_block(btree, path[level].bp_newreq.bpr_ptr,
1162                                         &bh);
1163         if (ret < 0)
1164                 goto err_out_curr_node;
1165
1166         nilfs_btree_node_init((struct nilfs_btree_node *)bh->b_data,
1167                               0, level, 0, ncblk, NULL, NULL);
1168         path[level].bp_sib_bh = bh;
1169         path[level].bp_op = nilfs_btree_grow;
1170
1171         level++;
1172         path[level].bp_op = nilfs_btree_do_insert;
1173
1174         /* a newly-created node block and a data block are added */
1175         stats->bs_nblocks += 2;
1176
1177         /* success */
1178  out:
1179         *levelp = level;
1180         return ret;
1181
1182         /* error */
1183  err_out_curr_node:
1184         nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1185  err_out_child_node:
1186         for (level--; level > NILFS_BTREE_LEVEL_DATA; level--) {
1187                 nilfs_btnode_delete(path[level].bp_sib_bh);
1188                 nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1189
1190         }
1191
1192         nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1193  err_out_data:
1194         *levelp = level;
1195         stats->bs_nblocks = 0;
1196         return ret;
1197 }
1198
1199 static void nilfs_btree_commit_insert(struct nilfs_bmap *btree,
1200                                       struct nilfs_btree_path *path,
1201                                       int maxlevel, __u64 key, __u64 ptr)
1202 {
1203         struct inode *dat = NULL;
1204         int level;
1205
1206         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
1207         ptr = path[NILFS_BTREE_LEVEL_DATA].bp_newreq.bpr_ptr;
1208         if (NILFS_BMAP_USE_VBN(btree)) {
1209                 nilfs_bmap_set_target_v(btree, key, ptr);
1210                 dat = nilfs_bmap_get_dat(btree);
1211         }
1212
1213         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
1214                 nilfs_bmap_commit_alloc_ptr(btree,
1215                                             &path[level - 1].bp_newreq, dat);
1216                 path[level].bp_op(btree, path, level, &key, &ptr);
1217         }
1218
1219         if (!nilfs_bmap_dirty(btree))
1220                 nilfs_bmap_set_dirty(btree);
1221 }
1222
1223 static int nilfs_btree_insert(struct nilfs_bmap *btree, __u64 key, __u64 ptr)
1224 {
1225         struct nilfs_btree_path *path;
1226         struct nilfs_bmap_stats stats;
1227         int level, ret;
1228
1229         path = nilfs_btree_alloc_path();
1230         if (path == NULL)
1231                 return -ENOMEM;
1232
1233         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
1234                                     NILFS_BTREE_LEVEL_NODE_MIN, 0);
1235         if (ret != -ENOENT) {
1236                 if (ret == 0)
1237                         ret = -EEXIST;
1238                 goto out;
1239         }
1240
1241         ret = nilfs_btree_prepare_insert(btree, path, &level, key, ptr, &stats);
1242         if (ret < 0)
1243                 goto out;
1244         nilfs_btree_commit_insert(btree, path, level, key, ptr);
1245         nilfs_inode_add_blocks(btree->b_inode, stats.bs_nblocks);
1246
1247  out:
1248         nilfs_btree_free_path(path);
1249         return ret;
1250 }
1251
1252 static void nilfs_btree_do_delete(struct nilfs_bmap *btree,
1253                                   struct nilfs_btree_path *path,
1254                                   int level, __u64 *keyp, __u64 *ptrp)
1255 {
1256         struct nilfs_btree_node *node;
1257         int ncblk;
1258
1259         if (level < nilfs_btree_height(btree) - 1) {
1260                 node = nilfs_btree_get_nonroot_node(path, level);
1261                 ncblk = nilfs_btree_nchildren_per_block(btree);
1262                 nilfs_btree_node_delete(node, path[level].bp_index,
1263                                         keyp, ptrp, ncblk);
1264                 if (!buffer_dirty(path[level].bp_bh))
1265                         mark_buffer_dirty(path[level].bp_bh);
1266                 if (path[level].bp_index == 0)
1267                         nilfs_btree_promote_key(btree, path, level + 1,
1268                                 nilfs_btree_node_get_key(node, 0));
1269         } else {
1270                 node = nilfs_btree_get_root(btree);
1271                 nilfs_btree_node_delete(node, path[level].bp_index,
1272                                         keyp, ptrp,
1273                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
1274         }
1275 }
1276
1277 static void nilfs_btree_borrow_left(struct nilfs_bmap *btree,
1278                                     struct nilfs_btree_path *path,
1279                                     int level, __u64 *keyp, __u64 *ptrp)
1280 {
1281         struct nilfs_btree_node *node, *left;
1282         int nchildren, lnchildren, n, ncblk;
1283
1284         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1285
1286         node = nilfs_btree_get_nonroot_node(path, level);
1287         left = nilfs_btree_get_sib_node(path, level);
1288         nchildren = nilfs_btree_node_get_nchildren(node);
1289         lnchildren = nilfs_btree_node_get_nchildren(left);
1290         ncblk = nilfs_btree_nchildren_per_block(btree);
1291
1292         n = (nchildren + lnchildren) / 2 - nchildren;
1293
1294         nilfs_btree_node_move_right(left, node, n, ncblk, ncblk);
1295
1296         if (!buffer_dirty(path[level].bp_bh))
1297                 mark_buffer_dirty(path[level].bp_bh);
1298         if (!buffer_dirty(path[level].bp_sib_bh))
1299                 mark_buffer_dirty(path[level].bp_sib_bh);
1300
1301         nilfs_btree_promote_key(btree, path, level + 1,
1302                                 nilfs_btree_node_get_key(node, 0));
1303
1304         brelse(path[level].bp_sib_bh);
1305         path[level].bp_sib_bh = NULL;
1306         path[level].bp_index += n;
1307 }
1308
1309 static void nilfs_btree_borrow_right(struct nilfs_bmap *btree,
1310                                      struct nilfs_btree_path *path,
1311                                      int level, __u64 *keyp, __u64 *ptrp)
1312 {
1313         struct nilfs_btree_node *node, *right;
1314         int nchildren, rnchildren, n, ncblk;
1315
1316         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1317
1318         node = nilfs_btree_get_nonroot_node(path, level);
1319         right = nilfs_btree_get_sib_node(path, level);
1320         nchildren = nilfs_btree_node_get_nchildren(node);
1321         rnchildren = nilfs_btree_node_get_nchildren(right);
1322         ncblk = nilfs_btree_nchildren_per_block(btree);
1323
1324         n = (nchildren + rnchildren) / 2 - nchildren;
1325
1326         nilfs_btree_node_move_left(node, right, n, ncblk, ncblk);
1327
1328         if (!buffer_dirty(path[level].bp_bh))
1329                 mark_buffer_dirty(path[level].bp_bh);
1330         if (!buffer_dirty(path[level].bp_sib_bh))
1331                 mark_buffer_dirty(path[level].bp_sib_bh);
1332
1333         path[level + 1].bp_index++;
1334         nilfs_btree_promote_key(btree, path, level + 1,
1335                                 nilfs_btree_node_get_key(right, 0));
1336         path[level + 1].bp_index--;
1337
1338         brelse(path[level].bp_sib_bh);
1339         path[level].bp_sib_bh = NULL;
1340 }
1341
1342 static void nilfs_btree_concat_left(struct nilfs_bmap *btree,
1343                                     struct nilfs_btree_path *path,
1344                                     int level, __u64 *keyp, __u64 *ptrp)
1345 {
1346         struct nilfs_btree_node *node, *left;
1347         int n, ncblk;
1348
1349         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1350
1351         node = nilfs_btree_get_nonroot_node(path, level);
1352         left = nilfs_btree_get_sib_node(path, level);
1353         ncblk = nilfs_btree_nchildren_per_block(btree);
1354
1355         n = nilfs_btree_node_get_nchildren(node);
1356
1357         nilfs_btree_node_move_left(left, node, n, ncblk, ncblk);
1358
1359         if (!buffer_dirty(path[level].bp_sib_bh))
1360                 mark_buffer_dirty(path[level].bp_sib_bh);
1361
1362         nilfs_btnode_delete(path[level].bp_bh);
1363         path[level].bp_bh = path[level].bp_sib_bh;
1364         path[level].bp_sib_bh = NULL;
1365         path[level].bp_index += nilfs_btree_node_get_nchildren(left);
1366 }
1367
1368 static void nilfs_btree_concat_right(struct nilfs_bmap *btree,
1369                                      struct nilfs_btree_path *path,
1370                                      int level, __u64 *keyp, __u64 *ptrp)
1371 {
1372         struct nilfs_btree_node *node, *right;
1373         int n, ncblk;
1374
1375         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1376
1377         node = nilfs_btree_get_nonroot_node(path, level);
1378         right = nilfs_btree_get_sib_node(path, level);
1379         ncblk = nilfs_btree_nchildren_per_block(btree);
1380
1381         n = nilfs_btree_node_get_nchildren(right);
1382
1383         nilfs_btree_node_move_left(node, right, n, ncblk, ncblk);
1384
1385         if (!buffer_dirty(path[level].bp_bh))
1386                 mark_buffer_dirty(path[level].bp_bh);
1387
1388         nilfs_btnode_delete(path[level].bp_sib_bh);
1389         path[level].bp_sib_bh = NULL;
1390         path[level + 1].bp_index++;
1391 }
1392
1393 static void nilfs_btree_shrink(struct nilfs_bmap *btree,
1394                                struct nilfs_btree_path *path,
1395                                int level, __u64 *keyp, __u64 *ptrp)
1396 {
1397         struct nilfs_btree_node *root, *child;
1398         int n, ncblk;
1399
1400         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1401
1402         root = nilfs_btree_get_root(btree);
1403         child = nilfs_btree_get_nonroot_node(path, level);
1404         ncblk = nilfs_btree_nchildren_per_block(btree);
1405
1406         nilfs_btree_node_delete(root, 0, NULL, NULL,
1407                                 NILFS_BTREE_ROOT_NCHILDREN_MAX);
1408         nilfs_btree_node_set_level(root, level);
1409         n = nilfs_btree_node_get_nchildren(child);
1410         nilfs_btree_node_move_left(root, child, n,
1411                                    NILFS_BTREE_ROOT_NCHILDREN_MAX, ncblk);
1412
1413         nilfs_btnode_delete(path[level].bp_bh);
1414         path[level].bp_bh = NULL;
1415 }
1416
1417 static void nilfs_btree_nop(struct nilfs_bmap *btree,
1418                             struct nilfs_btree_path *path,
1419                             int level, __u64 *keyp, __u64 *ptrp)
1420 {
1421 }
1422
1423 static int nilfs_btree_prepare_delete(struct nilfs_bmap *btree,
1424                                       struct nilfs_btree_path *path,
1425                                       int *levelp,
1426                                       struct nilfs_bmap_stats *stats,
1427                                       struct inode *dat)
1428 {
1429         struct buffer_head *bh;
1430         struct nilfs_btree_node *node, *parent, *sib;
1431         __u64 sibptr;
1432         int pindex, dindex, level, ncmin, ncmax, ncblk, ret;
1433
1434         ret = 0;
1435         stats->bs_nblocks = 0;
1436         ncmin = NILFS_BTREE_NODE_NCHILDREN_MIN(nilfs_btree_node_size(btree));
1437         ncblk = nilfs_btree_nchildren_per_block(btree);
1438
1439         for (level = NILFS_BTREE_LEVEL_NODE_MIN, dindex = path[level].bp_index;
1440              level < nilfs_btree_height(btree) - 1;
1441              level++) {
1442                 node = nilfs_btree_get_nonroot_node(path, level);
1443                 path[level].bp_oldreq.bpr_ptr =
1444                         nilfs_btree_node_get_ptr(node, dindex, ncblk);
1445                 ret = nilfs_bmap_prepare_end_ptr(btree,
1446                                                  &path[level].bp_oldreq, dat);
1447                 if (ret < 0)
1448                         goto err_out_child_node;
1449
1450                 if (nilfs_btree_node_get_nchildren(node) > ncmin) {
1451                         path[level].bp_op = nilfs_btree_do_delete;
1452                         stats->bs_nblocks++;
1453                         goto out;
1454                 }
1455
1456                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1457                 pindex = path[level + 1].bp_index;
1458                 dindex = pindex;
1459
1460                 if (pindex > 0) {
1461                         /* left sibling */
1462                         sibptr = nilfs_btree_node_get_ptr(parent, pindex - 1,
1463                                                           ncmax);
1464                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1465                         if (ret < 0)
1466                                 goto err_out_curr_node;
1467                         sib = (struct nilfs_btree_node *)bh->b_data;
1468                         if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
1469                                 path[level].bp_sib_bh = bh;
1470                                 path[level].bp_op = nilfs_btree_borrow_left;
1471                                 stats->bs_nblocks++;
1472                                 goto out;
1473                         } else {
1474                                 path[level].bp_sib_bh = bh;
1475                                 path[level].bp_op = nilfs_btree_concat_left;
1476                                 stats->bs_nblocks++;
1477                                 /* continue; */
1478                         }
1479                 } else if (pindex <
1480                            nilfs_btree_node_get_nchildren(parent) - 1) {
1481                         /* right sibling */
1482                         sibptr = nilfs_btree_node_get_ptr(parent, pindex + 1,
1483                                                           ncmax);
1484                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1485                         if (ret < 0)
1486                                 goto err_out_curr_node;
1487                         sib = (struct nilfs_btree_node *)bh->b_data;
1488                         if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
1489                                 path[level].bp_sib_bh = bh;
1490                                 path[level].bp_op = nilfs_btree_borrow_right;
1491                                 stats->bs_nblocks++;
1492                                 goto out;
1493                         } else {
1494                                 path[level].bp_sib_bh = bh;
1495                                 path[level].bp_op = nilfs_btree_concat_right;
1496                                 stats->bs_nblocks++;
1497                                 /*
1498                                  * When merging right sibling node
1499                                  * into the current node, pointer to
1500                                  * the right sibling node must be
1501                                  * terminated instead.  The adjustment
1502                                  * below is required for that.
1503                                  */
1504                                 dindex = pindex + 1;
1505                                 /* continue; */
1506                         }
1507                 } else {
1508                         /* no siblings */
1509                         /* the only child of the root node */
1510                         WARN_ON(level != nilfs_btree_height(btree) - 2);
1511                         if (nilfs_btree_node_get_nchildren(node) - 1 <=
1512                             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1513                                 path[level].bp_op = nilfs_btree_shrink;
1514                                 stats->bs_nblocks += 2;
1515                                 level++;
1516                                 path[level].bp_op = nilfs_btree_nop;
1517                                 goto shrink_root_child;
1518                         } else {
1519                                 path[level].bp_op = nilfs_btree_do_delete;
1520                                 stats->bs_nblocks++;
1521                                 goto out;
1522                         }
1523                 }
1524         }
1525
1526         /* child of the root node is deleted */
1527         path[level].bp_op = nilfs_btree_do_delete;
1528         stats->bs_nblocks++;
1529
1530 shrink_root_child:
1531         node = nilfs_btree_get_root(btree);
1532         path[level].bp_oldreq.bpr_ptr =
1533                 nilfs_btree_node_get_ptr(node, dindex,
1534                                          NILFS_BTREE_ROOT_NCHILDREN_MAX);
1535
1536         ret = nilfs_bmap_prepare_end_ptr(btree, &path[level].bp_oldreq, dat);
1537         if (ret < 0)
1538                 goto err_out_child_node;
1539
1540         /* success */
1541  out:
1542         *levelp = level;
1543         return ret;
1544
1545         /* error */
1546  err_out_curr_node:
1547         nilfs_bmap_abort_end_ptr(btree, &path[level].bp_oldreq, dat);
1548  err_out_child_node:
1549         for (level--; level >= NILFS_BTREE_LEVEL_NODE_MIN; level--) {
1550                 brelse(path[level].bp_sib_bh);
1551                 nilfs_bmap_abort_end_ptr(btree, &path[level].bp_oldreq, dat);
1552         }
1553         *levelp = level;
1554         stats->bs_nblocks = 0;
1555         return ret;
1556 }
1557
1558 static void nilfs_btree_commit_delete(struct nilfs_bmap *btree,
1559                                       struct nilfs_btree_path *path,
1560                                       int maxlevel, struct inode *dat)
1561 {
1562         int level;
1563
1564         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
1565                 nilfs_bmap_commit_end_ptr(btree, &path[level].bp_oldreq, dat);
1566                 path[level].bp_op(btree, path, level, NULL, NULL);
1567         }
1568
1569         if (!nilfs_bmap_dirty(btree))
1570                 nilfs_bmap_set_dirty(btree);
1571 }
1572
1573 static int nilfs_btree_delete(struct nilfs_bmap *btree, __u64 key)
1574
1575 {
1576         struct nilfs_btree_path *path;
1577         struct nilfs_bmap_stats stats;
1578         struct inode *dat;
1579         int level, ret;
1580
1581         path = nilfs_btree_alloc_path();
1582         if (path == NULL)
1583                 return -ENOMEM;
1584
1585         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
1586                                     NILFS_BTREE_LEVEL_NODE_MIN, 0);
1587         if (ret < 0)
1588                 goto out;
1589
1590
1591         dat = NILFS_BMAP_USE_VBN(btree) ? nilfs_bmap_get_dat(btree) : NULL;
1592
1593         ret = nilfs_btree_prepare_delete(btree, path, &level, &stats, dat);
1594         if (ret < 0)
1595                 goto out;
1596         nilfs_btree_commit_delete(btree, path, level, dat);
1597         nilfs_inode_sub_blocks(btree->b_inode, stats.bs_nblocks);
1598
1599 out:
1600         nilfs_btree_free_path(path);
1601         return ret;
1602 }
1603
1604 static int nilfs_btree_seek_key(const struct nilfs_bmap *btree, __u64 start,
1605                                 __u64 *keyp)
1606 {
1607         struct nilfs_btree_path *path;
1608         const int minlevel = NILFS_BTREE_LEVEL_NODE_MIN;
1609         int ret;
1610
1611         path = nilfs_btree_alloc_path();
1612         if (!path)
1613                 return -ENOMEM;
1614
1615         ret = nilfs_btree_do_lookup(btree, path, start, NULL, minlevel, 0);
1616         if (!ret)
1617                 *keyp = start;
1618         else if (ret == -ENOENT)
1619                 ret = nilfs_btree_get_next_key(btree, path, minlevel, keyp);
1620
1621         nilfs_btree_free_path(path);
1622         return ret;
1623 }
1624
1625 static int nilfs_btree_last_key(const struct nilfs_bmap *btree, __u64 *keyp)
1626 {
1627         struct nilfs_btree_path *path;
1628         int ret;
1629
1630         path = nilfs_btree_alloc_path();
1631         if (path == NULL)
1632                 return -ENOMEM;
1633
1634         ret = nilfs_btree_do_lookup_last(btree, path, keyp, NULL);
1635
1636         nilfs_btree_free_path(path);
1637
1638         return ret;
1639 }
1640
1641 static int nilfs_btree_check_delete(struct nilfs_bmap *btree, __u64 key)
1642 {
1643         struct buffer_head *bh;
1644         struct nilfs_btree_node *root, *node;
1645         __u64 maxkey, nextmaxkey;
1646         __u64 ptr;
1647         int nchildren, ret;
1648
1649         root = nilfs_btree_get_root(btree);
1650         switch (nilfs_btree_height(btree)) {
1651         case 2:
1652                 bh = NULL;
1653                 node = root;
1654                 break;
1655         case 3:
1656                 nchildren = nilfs_btree_node_get_nchildren(root);
1657                 if (nchildren > 1)
1658                         return 0;
1659                 ptr = nilfs_btree_node_get_ptr(root, nchildren - 1,
1660                                                NILFS_BTREE_ROOT_NCHILDREN_MAX);
1661                 ret = nilfs_btree_get_block(btree, ptr, &bh);
1662                 if (ret < 0)
1663                         return ret;
1664                 node = (struct nilfs_btree_node *)bh->b_data;
1665                 break;
1666         default:
1667                 return 0;
1668         }
1669
1670         nchildren = nilfs_btree_node_get_nchildren(node);
1671         maxkey = nilfs_btree_node_get_key(node, nchildren - 1);
1672         nextmaxkey = (nchildren > 1) ?
1673                 nilfs_btree_node_get_key(node, nchildren - 2) : 0;
1674         if (bh != NULL)
1675                 brelse(bh);
1676
1677         return (maxkey == key) && (nextmaxkey < NILFS_BMAP_LARGE_LOW);
1678 }
1679
1680 static int nilfs_btree_gather_data(struct nilfs_bmap *btree,
1681                                    __u64 *keys, __u64 *ptrs, int nitems)
1682 {
1683         struct buffer_head *bh;
1684         struct nilfs_btree_node *node, *root;
1685         __le64 *dkeys;
1686         __le64 *dptrs;
1687         __u64 ptr;
1688         int nchildren, ncmax, i, ret;
1689
1690         root = nilfs_btree_get_root(btree);
1691         switch (nilfs_btree_height(btree)) {
1692         case 2:
1693                 bh = NULL;
1694                 node = root;
1695                 ncmax = NILFS_BTREE_ROOT_NCHILDREN_MAX;
1696                 break;
1697         case 3:
1698                 nchildren = nilfs_btree_node_get_nchildren(root);
1699                 WARN_ON(nchildren > 1);
1700                 ptr = nilfs_btree_node_get_ptr(root, nchildren - 1,
1701                                                NILFS_BTREE_ROOT_NCHILDREN_MAX);
1702                 ret = nilfs_btree_get_block(btree, ptr, &bh);
1703                 if (ret < 0)
1704                         return ret;
1705                 node = (struct nilfs_btree_node *)bh->b_data;
1706                 ncmax = nilfs_btree_nchildren_per_block(btree);
1707                 break;
1708         default:
1709                 node = NULL;
1710                 return -EINVAL;
1711         }
1712
1713         nchildren = nilfs_btree_node_get_nchildren(node);
1714         if (nchildren < nitems)
1715                 nitems = nchildren;
1716         dkeys = nilfs_btree_node_dkeys(node);
1717         dptrs = nilfs_btree_node_dptrs(node, ncmax);
1718         for (i = 0; i < nitems; i++) {
1719                 keys[i] = le64_to_cpu(dkeys[i]);
1720                 ptrs[i] = le64_to_cpu(dptrs[i]);
1721         }
1722
1723         if (bh != NULL)
1724                 brelse(bh);
1725
1726         return nitems;
1727 }
1728
1729 static int
1730 nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *btree, __u64 key,
1731                                        union nilfs_bmap_ptr_req *dreq,
1732                                        union nilfs_bmap_ptr_req *nreq,
1733                                        struct buffer_head **bhp,
1734                                        struct nilfs_bmap_stats *stats)
1735 {
1736         struct buffer_head *bh;
1737         struct inode *dat = NULL;
1738         int ret;
1739
1740         stats->bs_nblocks = 0;
1741
1742         /* for data */
1743         /* cannot find near ptr */
1744         if (NILFS_BMAP_USE_VBN(btree)) {
1745                 dreq->bpr_ptr = nilfs_btree_find_target_v(btree, NULL, key);
1746                 dat = nilfs_bmap_get_dat(btree);
1747         }
1748
1749         ret = nilfs_bmap_prepare_alloc_ptr(btree, dreq, dat);
1750         if (ret < 0)
1751                 return ret;
1752
1753         *bhp = NULL;
1754         stats->bs_nblocks++;
1755         if (nreq != NULL) {
1756                 nreq->bpr_ptr = dreq->bpr_ptr + 1;
1757                 ret = nilfs_bmap_prepare_alloc_ptr(btree, nreq, dat);
1758                 if (ret < 0)
1759                         goto err_out_dreq;
1760
1761                 ret = nilfs_btree_get_new_block(btree, nreq->bpr_ptr, &bh);
1762                 if (ret < 0)
1763                         goto err_out_nreq;
1764
1765                 *bhp = bh;
1766                 stats->bs_nblocks++;
1767         }
1768
1769         /* success */
1770         return 0;
1771
1772         /* error */
1773  err_out_nreq:
1774         nilfs_bmap_abort_alloc_ptr(btree, nreq, dat);
1775  err_out_dreq:
1776         nilfs_bmap_abort_alloc_ptr(btree, dreq, dat);
1777         stats->bs_nblocks = 0;
1778         return ret;
1779
1780 }
1781
1782 static void
1783 nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *btree,
1784                                       __u64 key, __u64 ptr,
1785                                       const __u64 *keys, const __u64 *ptrs,
1786                                       int n,
1787                                       union nilfs_bmap_ptr_req *dreq,
1788                                       union nilfs_bmap_ptr_req *nreq,
1789                                       struct buffer_head *bh)
1790 {
1791         struct nilfs_btree_node *node;
1792         struct inode *dat;
1793         __u64 tmpptr;
1794         int ncblk;
1795
1796         /* free resources */
1797         if (btree->b_ops->bop_clear != NULL)
1798                 btree->b_ops->bop_clear(btree);
1799
1800         /* ptr must be a pointer to a buffer head. */
1801         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
1802
1803         /* convert and insert */
1804         dat = NILFS_BMAP_USE_VBN(btree) ? nilfs_bmap_get_dat(btree) : NULL;
1805         __nilfs_btree_init(btree);
1806         if (nreq != NULL) {
1807                 nilfs_bmap_commit_alloc_ptr(btree, dreq, dat);
1808                 nilfs_bmap_commit_alloc_ptr(btree, nreq, dat);
1809
1810                 /* create child node at level 1 */
1811                 node = (struct nilfs_btree_node *)bh->b_data;
1812                 ncblk = nilfs_btree_nchildren_per_block(btree);
1813                 nilfs_btree_node_init(node, 0, 1, n, ncblk, keys, ptrs);
1814                 nilfs_btree_node_insert(node, n, key, dreq->bpr_ptr, ncblk);
1815                 if (!buffer_dirty(bh))
1816                         mark_buffer_dirty(bh);
1817                 if (!nilfs_bmap_dirty(btree))
1818                         nilfs_bmap_set_dirty(btree);
1819
1820                 brelse(bh);
1821
1822                 /* create root node at level 2 */
1823                 node = nilfs_btree_get_root(btree);
1824                 tmpptr = nreq->bpr_ptr;
1825                 nilfs_btree_node_init(node, NILFS_BTREE_NODE_ROOT, 2, 1,
1826                                       NILFS_BTREE_ROOT_NCHILDREN_MAX,
1827                                       &keys[0], &tmpptr);
1828         } else {
1829                 nilfs_bmap_commit_alloc_ptr(btree, dreq, dat);
1830
1831                 /* create root node at level 1 */
1832                 node = nilfs_btree_get_root(btree);
1833                 nilfs_btree_node_init(node, NILFS_BTREE_NODE_ROOT, 1, n,
1834                                       NILFS_BTREE_ROOT_NCHILDREN_MAX,
1835                                       keys, ptrs);
1836                 nilfs_btree_node_insert(node, n, key, dreq->bpr_ptr,
1837                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
1838                 if (!nilfs_bmap_dirty(btree))
1839                         nilfs_bmap_set_dirty(btree);
1840         }
1841
1842         if (NILFS_BMAP_USE_VBN(btree))
1843                 nilfs_bmap_set_target_v(btree, key, dreq->bpr_ptr);
1844 }
1845
1846 /**
1847  * nilfs_btree_convert_and_insert -
1848  * @bmap:
1849  * @key:
1850  * @ptr:
1851  * @keys:
1852  * @ptrs:
1853  * @n:
1854  */
1855 int nilfs_btree_convert_and_insert(struct nilfs_bmap *btree,
1856                                    __u64 key, __u64 ptr,
1857                                    const __u64 *keys, const __u64 *ptrs, int n)
1858 {
1859         struct buffer_head *bh;
1860         union nilfs_bmap_ptr_req dreq, nreq, *di, *ni;
1861         struct nilfs_bmap_stats stats;
1862         int ret;
1863
1864         if (n + 1 <= NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1865                 di = &dreq;
1866                 ni = NULL;
1867         } else if ((n + 1) <= NILFS_BTREE_NODE_NCHILDREN_MAX(
1868                            1 << btree->b_inode->i_blkbits)) {
1869                 di = &dreq;
1870                 ni = &nreq;
1871         } else {
1872                 di = NULL;
1873                 ni = NULL;
1874                 BUG();
1875         }
1876
1877         ret = nilfs_btree_prepare_convert_and_insert(btree, key, di, ni, &bh,
1878                                                      &stats);
1879         if (ret < 0)
1880                 return ret;
1881         nilfs_btree_commit_convert_and_insert(btree, key, ptr, keys, ptrs, n,
1882                                               di, ni, bh);
1883         nilfs_inode_add_blocks(btree->b_inode, stats.bs_nblocks);
1884         return 0;
1885 }
1886
1887 static int nilfs_btree_propagate_p(struct nilfs_bmap *btree,
1888                                    struct nilfs_btree_path *path,
1889                                    int level,
1890                                    struct buffer_head *bh)
1891 {
1892         while ((++level < nilfs_btree_height(btree) - 1) &&
1893                !buffer_dirty(path[level].bp_bh))
1894                 mark_buffer_dirty(path[level].bp_bh);
1895
1896         return 0;
1897 }
1898
1899 static int nilfs_btree_prepare_update_v(struct nilfs_bmap *btree,
1900                                         struct nilfs_btree_path *path,
1901                                         int level, struct inode *dat)
1902 {
1903         struct nilfs_btree_node *parent;
1904         int ncmax, ret;
1905
1906         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1907         path[level].bp_oldreq.bpr_ptr =
1908                 nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
1909                                          ncmax);
1910         path[level].bp_newreq.bpr_ptr = path[level].bp_oldreq.bpr_ptr + 1;
1911         ret = nilfs_dat_prepare_update(dat, &path[level].bp_oldreq.bpr_req,
1912                                        &path[level].bp_newreq.bpr_req);
1913         if (ret < 0)
1914                 return ret;
1915
1916         if (buffer_nilfs_node(path[level].bp_bh)) {
1917                 path[level].bp_ctxt.oldkey = path[level].bp_oldreq.bpr_ptr;
1918                 path[level].bp_ctxt.newkey = path[level].bp_newreq.bpr_ptr;
1919                 path[level].bp_ctxt.bh = path[level].bp_bh;
1920                 ret = nilfs_btnode_prepare_change_key(
1921                         &NILFS_BMAP_I(btree)->i_btnode_cache,
1922                         &path[level].bp_ctxt);
1923                 if (ret < 0) {
1924                         nilfs_dat_abort_update(dat,
1925                                                &path[level].bp_oldreq.bpr_req,
1926                                                &path[level].bp_newreq.bpr_req);
1927                         return ret;
1928                 }
1929         }
1930
1931         return 0;
1932 }
1933
1934 static void nilfs_btree_commit_update_v(struct nilfs_bmap *btree,
1935                                         struct nilfs_btree_path *path,
1936                                         int level, struct inode *dat)
1937 {
1938         struct nilfs_btree_node *parent;
1939         int ncmax;
1940
1941         nilfs_dat_commit_update(dat, &path[level].bp_oldreq.bpr_req,
1942                                 &path[level].bp_newreq.bpr_req,
1943                                 btree->b_ptr_type == NILFS_BMAP_PTR_VS);
1944
1945         if (buffer_nilfs_node(path[level].bp_bh)) {
1946                 nilfs_btnode_commit_change_key(
1947                         &NILFS_BMAP_I(btree)->i_btnode_cache,
1948                         &path[level].bp_ctxt);
1949                 path[level].bp_bh = path[level].bp_ctxt.bh;
1950         }
1951         set_buffer_nilfs_volatile(path[level].bp_bh);
1952
1953         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1954         nilfs_btree_node_set_ptr(parent, path[level + 1].bp_index,
1955                                  path[level].bp_newreq.bpr_ptr, ncmax);
1956 }
1957
1958 static void nilfs_btree_abort_update_v(struct nilfs_bmap *btree,
1959                                        struct nilfs_btree_path *path,
1960                                        int level, struct inode *dat)
1961 {
1962         nilfs_dat_abort_update(dat, &path[level].bp_oldreq.bpr_req,
1963                                &path[level].bp_newreq.bpr_req);
1964         if (buffer_nilfs_node(path[level].bp_bh))
1965                 nilfs_btnode_abort_change_key(
1966                         &NILFS_BMAP_I(btree)->i_btnode_cache,
1967                         &path[level].bp_ctxt);
1968 }
1969
1970 static int nilfs_btree_prepare_propagate_v(struct nilfs_bmap *btree,
1971                                            struct nilfs_btree_path *path,
1972                                            int minlevel, int *maxlevelp,
1973                                            struct inode *dat)
1974 {
1975         int level, ret;
1976
1977         level = minlevel;
1978         if (!buffer_nilfs_volatile(path[level].bp_bh)) {
1979                 ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
1980                 if (ret < 0)
1981                         return ret;
1982         }
1983         while ((++level < nilfs_btree_height(btree) - 1) &&
1984                !buffer_dirty(path[level].bp_bh)) {
1985
1986                 WARN_ON(buffer_nilfs_volatile(path[level].bp_bh));
1987                 ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
1988                 if (ret < 0)
1989                         goto out;
1990         }
1991
1992         /* success */
1993         *maxlevelp = level - 1;
1994         return 0;
1995
1996         /* error */
1997  out:
1998         while (--level > minlevel)
1999                 nilfs_btree_abort_update_v(btree, path, level, dat);
2000         if (!buffer_nilfs_volatile(path[level].bp_bh))
2001                 nilfs_btree_abort_update_v(btree, path, level, dat);
2002         return ret;
2003 }
2004
2005 static void nilfs_btree_commit_propagate_v(struct nilfs_bmap *btree,
2006                                            struct nilfs_btree_path *path,
2007                                            int minlevel, int maxlevel,
2008                                            struct buffer_head *bh,
2009                                            struct inode *dat)
2010 {
2011         int level;
2012
2013         if (!buffer_nilfs_volatile(path[minlevel].bp_bh))
2014                 nilfs_btree_commit_update_v(btree, path, minlevel, dat);
2015
2016         for (level = minlevel + 1; level <= maxlevel; level++)
2017                 nilfs_btree_commit_update_v(btree, path, level, dat);
2018 }
2019
2020 static int nilfs_btree_propagate_v(struct nilfs_bmap *btree,
2021                                    struct nilfs_btree_path *path,
2022                                    int level, struct buffer_head *bh)
2023 {
2024         int maxlevel = 0, ret;
2025         struct nilfs_btree_node *parent;
2026         struct inode *dat = nilfs_bmap_get_dat(btree);
2027         __u64 ptr;
2028         int ncmax;
2029
2030         get_bh(bh);
2031         path[level].bp_bh = bh;
2032         ret = nilfs_btree_prepare_propagate_v(btree, path, level, &maxlevel,
2033                                               dat);
2034         if (ret < 0)
2035                 goto out;
2036
2037         if (buffer_nilfs_volatile(path[level].bp_bh)) {
2038                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2039                 ptr = nilfs_btree_node_get_ptr(parent,
2040                                                path[level + 1].bp_index,
2041                                                ncmax);
2042                 ret = nilfs_dat_mark_dirty(dat, ptr);
2043                 if (ret < 0)
2044                         goto out;
2045         }
2046
2047         nilfs_btree_commit_propagate_v(btree, path, level, maxlevel, bh, dat);
2048
2049  out:
2050         brelse(path[level].bp_bh);
2051         path[level].bp_bh = NULL;
2052         return ret;
2053 }
2054
2055 static int nilfs_btree_propagate(struct nilfs_bmap *btree,
2056                                  struct buffer_head *bh)
2057 {
2058         struct nilfs_btree_path *path;
2059         struct nilfs_btree_node *node;
2060         __u64 key;
2061         int level, ret;
2062
2063         WARN_ON(!buffer_dirty(bh));
2064
2065         path = nilfs_btree_alloc_path();
2066         if (path == NULL)
2067                 return -ENOMEM;
2068
2069         if (buffer_nilfs_node(bh)) {
2070                 node = (struct nilfs_btree_node *)bh->b_data;
2071                 key = nilfs_btree_node_get_key(node, 0);
2072                 level = nilfs_btree_node_get_level(node);
2073         } else {
2074                 key = nilfs_bmap_data_get_key(btree, bh);
2075                 level = NILFS_BTREE_LEVEL_DATA;
2076         }
2077
2078         ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
2079         if (ret < 0) {
2080                 if (unlikely(ret == -ENOENT))
2081                         printk(KERN_CRIT "%s: key = %llu, level == %d\n",
2082                                __func__, (unsigned long long)key, level);
2083                 goto out;
2084         }
2085
2086         ret = NILFS_BMAP_USE_VBN(btree) ?
2087                 nilfs_btree_propagate_v(btree, path, level, bh) :
2088                 nilfs_btree_propagate_p(btree, path, level, bh);
2089
2090  out:
2091         nilfs_btree_free_path(path);
2092
2093         return ret;
2094 }
2095
2096 static int nilfs_btree_propagate_gc(struct nilfs_bmap *btree,
2097                                     struct buffer_head *bh)
2098 {
2099         return nilfs_dat_mark_dirty(nilfs_bmap_get_dat(btree), bh->b_blocknr);
2100 }
2101
2102 static void nilfs_btree_add_dirty_buffer(struct nilfs_bmap *btree,
2103                                          struct list_head *lists,
2104                                          struct buffer_head *bh)
2105 {
2106         struct list_head *head;
2107         struct buffer_head *cbh;
2108         struct nilfs_btree_node *node, *cnode;
2109         __u64 key, ckey;
2110         int level;
2111
2112         get_bh(bh);
2113         node = (struct nilfs_btree_node *)bh->b_data;
2114         key = nilfs_btree_node_get_key(node, 0);
2115         level = nilfs_btree_node_get_level(node);
2116         if (level < NILFS_BTREE_LEVEL_NODE_MIN ||
2117             level >= NILFS_BTREE_LEVEL_MAX) {
2118                 dump_stack();
2119                 printk(KERN_WARNING
2120                        "%s: invalid btree level: %d (key=%llu, ino=%lu, "
2121                        "blocknr=%llu)\n",
2122                        __func__, level, (unsigned long long)key,
2123                        NILFS_BMAP_I(btree)->vfs_inode.i_ino,
2124                        (unsigned long long)bh->b_blocknr);
2125                 return;
2126         }
2127
2128         list_for_each(head, &lists[level]) {
2129                 cbh = list_entry(head, struct buffer_head, b_assoc_buffers);
2130                 cnode = (struct nilfs_btree_node *)cbh->b_data;
2131                 ckey = nilfs_btree_node_get_key(cnode, 0);
2132                 if (key < ckey)
2133                         break;
2134         }
2135         list_add_tail(&bh->b_assoc_buffers, head);
2136 }
2137
2138 static void nilfs_btree_lookup_dirty_buffers(struct nilfs_bmap *btree,
2139                                              struct list_head *listp)
2140 {
2141         struct address_space *btcache = &NILFS_BMAP_I(btree)->i_btnode_cache;
2142         struct list_head lists[NILFS_BTREE_LEVEL_MAX];
2143         struct pagevec pvec;
2144         struct buffer_head *bh, *head;
2145         pgoff_t index = 0;
2146         int level, i;
2147
2148         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
2149              level < NILFS_BTREE_LEVEL_MAX;
2150              level++)
2151                 INIT_LIST_HEAD(&lists[level]);
2152
2153         pagevec_init(&pvec, 0);
2154
2155         while (pagevec_lookup_tag(&pvec, btcache, &index, PAGECACHE_TAG_DIRTY,
2156                                   PAGEVEC_SIZE)) {
2157                 for (i = 0; i < pagevec_count(&pvec); i++) {
2158                         bh = head = page_buffers(pvec.pages[i]);
2159                         do {
2160                                 if (buffer_dirty(bh))
2161                                         nilfs_btree_add_dirty_buffer(btree,
2162                                                                      lists, bh);
2163                         } while ((bh = bh->b_this_page) != head);
2164                 }
2165                 pagevec_release(&pvec);
2166                 cond_resched();
2167         }
2168
2169         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
2170              level < NILFS_BTREE_LEVEL_MAX;
2171              level++)
2172                 list_splice_tail(&lists[level], listp);
2173 }
2174
2175 static int nilfs_btree_assign_p(struct nilfs_bmap *btree,
2176                                 struct nilfs_btree_path *path,
2177                                 int level,
2178                                 struct buffer_head **bh,
2179                                 sector_t blocknr,
2180                                 union nilfs_binfo *binfo)
2181 {
2182         struct nilfs_btree_node *parent;
2183         __u64 key;
2184         __u64 ptr;
2185         int ncmax, ret;
2186
2187         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2188         ptr = nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
2189                                        ncmax);
2190         if (buffer_nilfs_node(*bh)) {
2191                 path[level].bp_ctxt.oldkey = ptr;
2192                 path[level].bp_ctxt.newkey = blocknr;
2193                 path[level].bp_ctxt.bh = *bh;
2194                 ret = nilfs_btnode_prepare_change_key(
2195                         &NILFS_BMAP_I(btree)->i_btnode_cache,
2196                         &path[level].bp_ctxt);
2197                 if (ret < 0)
2198                         return ret;
2199                 nilfs_btnode_commit_change_key(
2200                         &NILFS_BMAP_I(btree)->i_btnode_cache,
2201                         &path[level].bp_ctxt);
2202                 *bh = path[level].bp_ctxt.bh;
2203         }
2204
2205         nilfs_btree_node_set_ptr(parent, path[level + 1].bp_index, blocknr,
2206                                  ncmax);
2207
2208         key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
2209         /* on-disk format */
2210         binfo->bi_dat.bi_blkoff = cpu_to_le64(key);
2211         binfo->bi_dat.bi_level = level;
2212
2213         return 0;
2214 }
2215
2216 static int nilfs_btree_assign_v(struct nilfs_bmap *btree,
2217                                 struct nilfs_btree_path *path,
2218                                 int level,
2219                                 struct buffer_head **bh,
2220                                 sector_t blocknr,
2221                                 union nilfs_binfo *binfo)
2222 {
2223         struct nilfs_btree_node *parent;
2224         struct inode *dat = nilfs_bmap_get_dat(btree);
2225         __u64 key;
2226         __u64 ptr;
2227         union nilfs_bmap_ptr_req req;
2228         int ncmax, ret;
2229
2230         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2231         ptr = nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
2232                                        ncmax);
2233         req.bpr_ptr = ptr;
2234         ret = nilfs_dat_prepare_start(dat, &req.bpr_req);
2235         if (ret < 0)
2236                 return ret;
2237         nilfs_dat_commit_start(dat, &req.bpr_req, blocknr);
2238
2239         key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
2240         /* on-disk format */
2241         binfo->bi_v.bi_vblocknr = cpu_to_le64(ptr);
2242         binfo->bi_v.bi_blkoff = cpu_to_le64(key);
2243
2244         return 0;
2245 }
2246
2247 static int nilfs_btree_assign(struct nilfs_bmap *btree,
2248                               struct buffer_head **bh,
2249                               sector_t blocknr,
2250                               union nilfs_binfo *binfo)
2251 {
2252         struct nilfs_btree_path *path;
2253         struct nilfs_btree_node *node;
2254         __u64 key;
2255         int level, ret;
2256
2257         path = nilfs_btree_alloc_path();
2258         if (path == NULL)
2259                 return -ENOMEM;
2260
2261         if (buffer_nilfs_node(*bh)) {
2262                 node = (struct nilfs_btree_node *)(*bh)->b_data;
2263                 key = nilfs_btree_node_get_key(node, 0);
2264                 level = nilfs_btree_node_get_level(node);
2265         } else {
2266                 key = nilfs_bmap_data_get_key(btree, *bh);
2267                 level = NILFS_BTREE_LEVEL_DATA;
2268         }
2269
2270         ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
2271         if (ret < 0) {
2272                 WARN_ON(ret == -ENOENT);
2273                 goto out;
2274         }
2275
2276         ret = NILFS_BMAP_USE_VBN(btree) ?
2277                 nilfs_btree_assign_v(btree, path, level, bh, blocknr, binfo) :
2278                 nilfs_btree_assign_p(btree, path, level, bh, blocknr, binfo);
2279
2280  out:
2281         nilfs_btree_free_path(path);
2282
2283         return ret;
2284 }
2285
2286 static int nilfs_btree_assign_gc(struct nilfs_bmap *btree,
2287                                  struct buffer_head **bh,
2288                                  sector_t blocknr,
2289                                  union nilfs_binfo *binfo)
2290 {
2291         struct nilfs_btree_node *node;
2292         __u64 key;
2293         int ret;
2294
2295         ret = nilfs_dat_move(nilfs_bmap_get_dat(btree), (*bh)->b_blocknr,
2296                              blocknr);
2297         if (ret < 0)
2298                 return ret;
2299
2300         if (buffer_nilfs_node(*bh)) {
2301                 node = (struct nilfs_btree_node *)(*bh)->b_data;
2302                 key = nilfs_btree_node_get_key(node, 0);
2303         } else
2304                 key = nilfs_bmap_data_get_key(btree, *bh);
2305
2306         /* on-disk format */
2307         binfo->bi_v.bi_vblocknr = cpu_to_le64((*bh)->b_blocknr);
2308         binfo->bi_v.bi_blkoff = cpu_to_le64(key);
2309
2310         return 0;
2311 }
2312
2313 static int nilfs_btree_mark(struct nilfs_bmap *btree, __u64 key, int level)
2314 {
2315         struct buffer_head *bh;
2316         struct nilfs_btree_path *path;
2317         __u64 ptr;
2318         int ret;
2319
2320         path = nilfs_btree_alloc_path();
2321         if (path == NULL)
2322                 return -ENOMEM;
2323
2324         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1, 0);
2325         if (ret < 0) {
2326                 WARN_ON(ret == -ENOENT);
2327                 goto out;
2328         }
2329         ret = nilfs_btree_get_block(btree, ptr, &bh);
2330         if (ret < 0) {
2331                 WARN_ON(ret == -ENOENT);
2332                 goto out;
2333         }
2334
2335         if (!buffer_dirty(bh))
2336                 mark_buffer_dirty(bh);
2337         brelse(bh);
2338         if (!nilfs_bmap_dirty(btree))
2339                 nilfs_bmap_set_dirty(btree);
2340
2341  out:
2342         nilfs_btree_free_path(path);
2343         return ret;
2344 }
2345
2346 static const struct nilfs_bmap_operations nilfs_btree_ops = {
2347         .bop_lookup             =       nilfs_btree_lookup,
2348         .bop_lookup_contig      =       nilfs_btree_lookup_contig,
2349         .bop_insert             =       nilfs_btree_insert,
2350         .bop_delete             =       nilfs_btree_delete,
2351         .bop_clear              =       NULL,
2352
2353         .bop_propagate          =       nilfs_btree_propagate,
2354
2355         .bop_lookup_dirty_buffers =     nilfs_btree_lookup_dirty_buffers,
2356
2357         .bop_assign             =       nilfs_btree_assign,
2358         .bop_mark               =       nilfs_btree_mark,
2359
2360         .bop_seek_key           =       nilfs_btree_seek_key,
2361         .bop_last_key           =       nilfs_btree_last_key,
2362
2363         .bop_check_insert       =       NULL,
2364         .bop_check_delete       =       nilfs_btree_check_delete,
2365         .bop_gather_data        =       nilfs_btree_gather_data,
2366 };
2367
2368 static const struct nilfs_bmap_operations nilfs_btree_ops_gc = {
2369         .bop_lookup             =       NULL,
2370         .bop_lookup_contig      =       NULL,
2371         .bop_insert             =       NULL,
2372         .bop_delete             =       NULL,
2373         .bop_clear              =       NULL,
2374
2375         .bop_propagate          =       nilfs_btree_propagate_gc,
2376
2377         .bop_lookup_dirty_buffers =     nilfs_btree_lookup_dirty_buffers,
2378
2379         .bop_assign             =       nilfs_btree_assign_gc,
2380         .bop_mark               =       NULL,
2381
2382         .bop_seek_key           =       NULL,
2383         .bop_last_key           =       NULL,
2384
2385         .bop_check_insert       =       NULL,
2386         .bop_check_delete       =       NULL,
2387         .bop_gather_data        =       NULL,
2388 };
2389
2390 static void __nilfs_btree_init(struct nilfs_bmap *bmap)
2391 {
2392         bmap->b_ops = &nilfs_btree_ops;
2393         bmap->b_nchildren_per_block =
2394                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
2395 }
2396
2397 int nilfs_btree_init(struct nilfs_bmap *bmap)
2398 {
2399         int ret = 0;
2400
2401         __nilfs_btree_init(bmap);
2402
2403         if (nilfs_btree_root_broken(nilfs_btree_get_root(bmap),
2404                                     bmap->b_inode->i_ino))
2405                 ret = -EIO;
2406         return ret;
2407 }
2408
2409 void nilfs_btree_init_gc(struct nilfs_bmap *bmap)
2410 {
2411         bmap->b_ops = &nilfs_btree_ops_gc;
2412         bmap->b_nchildren_per_block =
2413                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
2414 }