SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/btrfs/ctree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/sched.h>
  20 #include "ctree.h"
  21 #include "disk-io.h"
  22 #include "transaction.h"
  23 #include "print-tree.h"
  24
  25 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
  26                       *root, struct btrfs_path *path, int level);
  27 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
  28                       *root, struct btrfs_key *ins_key,
  29                       struct btrfs_path *path, int data_size, int extend);
  30 static int push_node_left(struct btrfs_trans_handle *trans,
  31                           struct btrfs_root *root, struct extent_buffer *dst,
  32                           struct extent_buffer *src);
  33 static int balance_node_right(struct btrfs_trans_handle *trans,
  34                               struct btrfs_root *root,
  35                               struct extent_buffer *dst_buf,
  36                               struct extent_buffer *src_buf);
  37 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  38                    struct btrfs_path *path, int level, int slot);
  39
  40 inline void btrfs_init_path(struct btrfs_path *p)
  41 {
  42         memset(p, 0, sizeof(*p));
  43 }
  44
  45 struct btrfs_path *btrfs_alloc_path(void)
  46 {
  47         struct btrfs_path *path;
  48         path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
  49         if (path) {
  50                 btrfs_init_path(path);
  51                 path->reada = 1;
  52         }
  53         return path;
  54 }
  55
  56 void btrfs_free_path(struct btrfs_path *p)
  57 {
  58         btrfs_release_path(NULL, p);
  59         kmem_cache_free(btrfs_path_cachep, p);
  60 }
  61
  62 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
  63 {
  64         int i;
  65         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
  66                 if (!p->nodes[i])
  67                         break;
  68                 free_extent_buffer(p->nodes[i]);
  69         }
  70         memset(p, 0, sizeof(*p));
  71 }
  72
  73 static void add_root_to_dirty_list(struct btrfs_root *root)
  74 {
  75         if (root->track_dirty && list_empty(&root->dirty_list)) {
  76                 list_add(&root->dirty_list,
  77                          &root->fs_info->dirty_cowonly_roots);
  78         }
  79 }
  80
  81 int btrfs_copy_root(struct btrfs_trans_handle *trans,
  82                       struct btrfs_root *root,
  83                       struct extent_buffer *buf,
  84                       struct extent_buffer **cow_ret, u64 new_root_objectid)
  85 {
  86         struct extent_buffer *cow;
  87         u32 nritems;
  88         int ret = 0;
  89         int level;
  90         struct btrfs_key first_key;
  91         struct btrfs_root *new_root;
  92
  93         new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
  94         if (!new_root)
  95                 return -ENOMEM;
  96
  97         memcpy(new_root, root, sizeof(*new_root));
  98         new_root->root_key.objectid = new_root_objectid;
  99
 100         WARN_ON(root->ref_cows && trans->transid !=
 101                 root->fs_info->running_transaction->transid);
 102         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 103
 104         level = btrfs_header_level(buf);
 105         nritems = btrfs_header_nritems(buf);
 106         if (nritems) {
 107                 if (level == 0)
 108                         btrfs_item_key_to_cpu(buf, &first_key, 0);
 109                 else
 110                         btrfs_node_key_to_cpu(buf, &first_key, 0);
 111         } else {
 112                 first_key.objectid = 0;
 113         }
 114         cow = __btrfs_alloc_free_block(trans, new_root, buf->len,
 115                                        new_root_objectid,
 116                                        trans->transid, first_key.objectid,
 117                                        level, buf->start, 0);
 118         if (IS_ERR(cow)) {
 119                 kfree(new_root);
 120                 return PTR_ERR(cow);
 121         }
 122
 123         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 124         btrfs_set_header_bytenr(cow, cow->start);
 125         btrfs_set_header_generation(cow, trans->transid);
 126         btrfs_set_header_owner(cow, new_root_objectid);
 127         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 128
 129         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 130         ret = btrfs_inc_ref(trans, new_root, buf);
 131         kfree(new_root);
 132
 133         if (ret)
 134                 return ret;
 135
 136         btrfs_mark_buffer_dirty(cow);
 137         *cow_ret = cow;
 138         return 0;
 139 }
 140
 141 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 142                              struct btrfs_root *root,
 143                              struct extent_buffer *buf,
 144                              struct extent_buffer *parent, int parent_slot,
 145                              struct extent_buffer **cow_ret,
 146                              u64 search_start, u64 empty_size)
 147 {
 148         u64 root_gen;
 149         struct extent_buffer *cow;
 150         u32 nritems;
 151         int ret = 0;
 152         int different_trans = 0;
 153         int level;
 154         struct btrfs_key first_key;
 155
 156         if (root->ref_cows) {
 157                 root_gen = trans->transid;
 158         } else {
 159                 root_gen = 0;
 160         }
 161         WARN_ON(root->ref_cows && trans->transid !=
 162                 root->fs_info->running_transaction->transid);
 163         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 164
 165         level = btrfs_header_level(buf);
 166         nritems = btrfs_header_nritems(buf);
 167         if (nritems) {
 168                 if (level == 0)
 169                         btrfs_item_key_to_cpu(buf, &first_key, 0);
 170                 else
 171                         btrfs_node_key_to_cpu(buf, &first_key, 0);
 172         } else {
 173                 first_key.objectid = 0;
 174         }
 175         cow = __btrfs_alloc_free_block(trans, root, buf->len,
 176                                      root->root_key.objectid,
 177                                      root_gen, first_key.objectid, level,
 178                                      search_start, empty_size);
 179         if (IS_ERR(cow))
 180                 return PTR_ERR(cow);
 181
 182         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 183         btrfs_set_header_bytenr(cow, cow->start);
 184         btrfs_set_header_generation(cow, trans->transid);
 185         btrfs_set_header_owner(cow, root->root_key.objectid);
 186         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 187
 188         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 189         if (btrfs_header_generation(buf) != trans->transid) {
 190                 different_trans = 1;
 191                 ret = btrfs_inc_ref(trans, root, buf);
 192                 if (ret)
 193                         return ret;
 194         } else {
 195                 clean_tree_block(trans, root, buf);
 196         }
 197
 198         if (buf == root->node) {
 199                 root_gen = btrfs_header_generation(buf);
 200                 root->node = cow;
 201                 extent_buffer_get(cow);
 202                 if (buf != root->commit_root) {
 203                         btrfs_free_extent(trans, root, buf->start,
 204                                           buf->len, root->root_key.objectid,
 205                                           root_gen, 0, 0, 1);
 206                 }
 207                 free_extent_buffer(buf);
 208                 add_root_to_dirty_list(root);
 209         } else {
 210                 root_gen = btrfs_header_generation(parent);
 211                 btrfs_set_node_blockptr(parent, parent_slot,
 212                                         cow->start);
 213                 WARN_ON(trans->transid == 0);
 214                 btrfs_set_node_ptr_generation(parent, parent_slot,
 215                                               trans->transid);
 216                 btrfs_mark_buffer_dirty(parent);
 217                 WARN_ON(btrfs_header_generation(parent) != trans->transid);
 218                 btrfs_free_extent(trans, root, buf->start, buf->len,
 219                                   btrfs_header_owner(parent), root_gen,
 220                                   0, 0, 1);
 221         }
 222         free_extent_buffer(buf);
 223         btrfs_mark_buffer_dirty(cow);
 224         *cow_ret = cow;
 225         return 0;
 226 }
 227
 228 int btrfs_cow_block(struct btrfs_trans_handle *trans,
 229                     struct btrfs_root *root, struct extent_buffer *buf,
 230                     struct extent_buffer *parent, int parent_slot,
 231                     struct extent_buffer **cow_ret)
 232 {
 233         u64 search_start;
 234         u64 header_trans;
 235         int ret;
 236
 237         if (trans->transaction != root->fs_info->running_transaction) {
 238                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 239                        root->fs_info->running_transaction->transid);
 240                 WARN_ON(1);
 241         }
 242         if (trans->transid != root->fs_info->generation) {
 243                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 244                        root->fs_info->generation);
 245                 WARN_ON(1);
 246         }
 247
 248         header_trans = btrfs_header_generation(buf);
 249         spin_lock(&root->fs_info->hash_lock);
 250         if (header_trans == trans->transid &&
 251             !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
 252                 *cow_ret = buf;
 253                 spin_unlock(&root->fs_info->hash_lock);
 254                 return 0;
 255         }
 256         spin_unlock(&root->fs_info->hash_lock);
 257         search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
 258         ret = __btrfs_cow_block(trans, root, buf, parent,
 259                                  parent_slot, cow_ret, search_start, 0);
 260         return ret;
 261 }
 262
 263 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
 264 {
 265         if (blocknr < other && other - (blocknr + blocksize) < 32768)
 266                 return 1;
 267         if (blocknr > other && blocknr - (other + blocksize) < 32768)
 268                 return 1;
 269         return 0;
 270 }
 271
 272 /*
 273  * compare two keys in a memcmp fashion
 274  */
 275 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
 276 {
 277         struct btrfs_key k1;
 278
 279         btrfs_disk_key_to_cpu(&k1, disk);
 280
 281         if (k1.objectid > k2->objectid)
 282                 return 1;
 283         if (k1.objectid < k2->objectid)
 284                 return -1;
 285         if (k1.type > k2->type)
 286                 return 1;
 287         if (k1.type < k2->type)
 288                 return -1;
 289         if (k1.offset > k2->offset)
 290                 return 1;
 291         if (k1.offset < k2->offset)
 292                 return -1;
 293         return 0;
 294 }
 295
 296
 297 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 298                        struct btrfs_root *root, struct extent_buffer *parent,
 299                        int start_slot, int cache_only, u64 *last_ret,
 300                        struct btrfs_key *progress)
 301 {
 302         struct extent_buffer *cur;
 303         struct extent_buffer *tmp;
 304         u64 blocknr;
 305         u64 search_start = *last_ret;
 306         u64 last_block = 0;
 307         u64 other;
 308         u32 parent_nritems;
 309         int end_slot;
 310         int i;
 311         int err = 0;
 312         int parent_level;
 313         int uptodate;
 314         u32 blocksize;
 315         int progress_passed = 0;
 316         struct btrfs_disk_key disk_key;
 317
 318         parent_level = btrfs_header_level(parent);
 319         if (cache_only && parent_level != 1)
 320                 return 0;
 321
 322         if (trans->transaction != root->fs_info->running_transaction) {
 323                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 324                        root->fs_info->running_transaction->transid);
 325                 WARN_ON(1);
 326         }
 327         if (trans->transid != root->fs_info->generation) {
 328                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 329                        root->fs_info->generation);
 330                 WARN_ON(1);
 331         }
 332
 333         parent_nritems = btrfs_header_nritems(parent);
 334         blocksize = btrfs_level_size(root, parent_level - 1);
 335         end_slot = parent_nritems;
 336
 337         if (parent_nritems == 1)
 338                 return 0;
 339
 340         for (i = start_slot; i < end_slot; i++) {
 341                 int close = 1;
 342
 343                 if (!parent->map_token) {
 344                         map_extent_buffer(parent,
 345                                         btrfs_node_key_ptr_offset(i),
 346                                         sizeof(struct btrfs_key_ptr),
 347                                         &parent->map_token, &parent->kaddr,
 348                                         &parent->map_start, &parent->map_len,
 349                                         KM_USER1);
 350                 }
 351                 btrfs_node_key(parent, &disk_key, i);
 352                 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
 353                         continue;
 354
 355                 progress_passed = 1;
 356                 blocknr = btrfs_node_blockptr(parent, i);
 357                 if (last_block == 0)
 358                         last_block = blocknr;
 359
 360                 if (i > 0) {
 361                         other = btrfs_node_blockptr(parent, i - 1);
 362                         close = close_blocks(blocknr, other, blocksize);
 363                 }
 364                 if (close && i < end_slot - 2) {
 365                         other = btrfs_node_blockptr(parent, i + 1);
 366                         close = close_blocks(blocknr, other, blocksize);
 367                 }
 368                 if (close) {
 369                         last_block = blocknr;
 370                         continue;
 371                 }
 372                 if (parent->map_token) {
 373                         unmap_extent_buffer(parent, parent->map_token,
 374                                             KM_USER1);
 375                         parent->map_token = NULL;
 376                 }
 377
 378                 cur = btrfs_find_tree_block(root, blocknr, blocksize);
 379                 if (cur)
 380                         uptodate = btrfs_buffer_uptodate(cur);
 381                 else
 382                         uptodate = 0;
 383                 if (!cur || !uptodate) {
 384                         if (cache_only) {
 385                                 free_extent_buffer(cur);
 386                                 continue;
 387                         }
 388                         if (!cur) {
 389                                 cur = read_tree_block(root, blocknr,
 390                                                          blocksize);
 391                         } else if (!uptodate) {
 392                                 btrfs_read_buffer(cur);
 393                         }
 394                 }
 395                 if (search_start == 0)
 396                         search_start = last_block;
 397
 398                 btrfs_verify_block_csum(root, cur);
 399                 err = __btrfs_cow_block(trans, root, cur, parent, i,
 400                                         &tmp, search_start,
 401                                         min(16 * blocksize,
 402                                             (end_slot - i) * blocksize));
 403                 if (err) {
 404                         free_extent_buffer(cur);
 405                         break;
 406                 }
 407                 search_start = tmp->start;
 408                 last_block = tmp->start;
 409                 *last_ret = search_start;
 410                 if (parent_level == 1)
 411                         btrfs_clear_buffer_defrag(tmp);
 412                 free_extent_buffer(tmp);
 413         }
 414         if (parent->map_token) {
 415                 unmap_extent_buffer(parent, parent->map_token,
 416                                     KM_USER1);
 417                 parent->map_token = NULL;
 418         }
 419         return err;
 420 }
 421
 422 /*
 423  * The leaf data grows from end-to-front in the node.
 424  * this returns the address of the start of the last item,
 425  * which is the stop of the leaf data stack
 426  */
 427 static inline unsigned int leaf_data_end(struct btrfs_root *root,
 428                                          struct extent_buffer *leaf)
 429 {
 430         u32 nr = btrfs_header_nritems(leaf);
 431         if (nr == 0)
 432                 return BTRFS_LEAF_DATA_SIZE(root);
 433         return btrfs_item_offset_nr(leaf, nr - 1);
 434 }
 435
 436 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
 437                       int level)
 438 {
 439         struct extent_buffer *parent = NULL;
 440         struct extent_buffer *node = path->nodes[level];
 441         struct btrfs_disk_key parent_key;
 442         struct btrfs_disk_key node_key;
 443         int parent_slot;
 444         int slot;
 445         struct btrfs_key cpukey;
 446         u32 nritems = btrfs_header_nritems(node);
 447
 448         if (path->nodes[level + 1])
 449                 parent = path->nodes[level + 1];
 450
 451         slot = path->slots[level];
 452         BUG_ON(nritems == 0);
 453         if (parent) {
 454                 parent_slot = path->slots[level + 1];
 455                 btrfs_node_key(parent, &parent_key, parent_slot);
 456                 btrfs_node_key(node, &node_key, 0);
 457                 BUG_ON(memcmp(&parent_key, &node_key,
 458                               sizeof(struct btrfs_disk_key)));
 459                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 460                        btrfs_header_bytenr(node));
 461         }
 462         BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
 463         if (slot != 0) {
 464                 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
 465                 btrfs_node_key(node, &node_key, slot);
 466                 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
 467         }
 468         if (slot < nritems - 1) {
 469                 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
 470                 btrfs_node_key(node, &node_key, slot);
 471                 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
 472         }
 473         return 0;
 474 }
 475
 476 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
 477                       int level)
 478 {
 479         struct extent_buffer *leaf = path->nodes[level];
 480         struct extent_buffer *parent = NULL;
 481         int parent_slot;
 482         struct btrfs_key cpukey;
 483         struct btrfs_disk_key parent_key;
 484         struct btrfs_disk_key leaf_key;
 485         int slot = path->slots[0];
 486
 487         u32 nritems = btrfs_header_nritems(leaf);
 488
 489         if (path->nodes[level + 1])
 490                 parent = path->nodes[level + 1];
 491
 492         if (nritems == 0)
 493                 return 0;
 494
 495         if (parent) {
 496                 parent_slot = path->slots[level + 1];
 497                 btrfs_node_key(parent, &parent_key, parent_slot);
 498                 btrfs_item_key(leaf, &leaf_key, 0);
 499
 500                 BUG_ON(memcmp(&parent_key, &leaf_key,
 501                        sizeof(struct btrfs_disk_key)));
 502                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 503                        btrfs_header_bytenr(leaf));
 504         }
 505 #if 0
 506         for (i = 0; nritems > 1 && i < nritems - 2; i++) {
 507                 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
 508                 btrfs_item_key(leaf, &leaf_key, i);
 509                 if (comp_keys(&leaf_key, &cpukey) >= 0) {
 510                         btrfs_print_leaf(root, leaf);
 511                         printk("slot %d offset bad key\n", i);
 512                         BUG_ON(1);
 513                 }
 514                 if (btrfs_item_offset_nr(leaf, i) !=
 515                         btrfs_item_end_nr(leaf, i + 1)) {
 516                         btrfs_print_leaf(root, leaf);
 517                         printk("slot %d offset bad\n", i);
 518                         BUG_ON(1);
 519                 }
 520                 if (i == 0) {
 521                         if (btrfs_item_offset_nr(leaf, i) +
 522                                btrfs_item_size_nr(leaf, i) !=
 523                                BTRFS_LEAF_DATA_SIZE(root)) {
 524                                 btrfs_print_leaf(root, leaf);
 525                                 printk("slot %d first offset bad\n", i);
 526                                 BUG_ON(1);
 527                         }
 528                 }
 529         }
 530         if (nritems > 0) {
 531                 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
 532                                 btrfs_print_leaf(root, leaf);
 533                                 printk("slot %d bad size \n", nritems - 1);
 534                                 BUG_ON(1);
 535                 }
 536         }
 537 #endif
 538         if (slot != 0 && slot < nritems - 1) {
 539                 btrfs_item_key(leaf, &leaf_key, slot);
 540                 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
 541                 if (comp_keys(&leaf_key, &cpukey) <= 0) {
 542                         btrfs_print_leaf(root, leaf);
 543                         printk("slot %d offset bad key\n", slot);
 544                         BUG_ON(1);
 545                 }
 546                 if (btrfs_item_offset_nr(leaf, slot - 1) !=
 547                        btrfs_item_end_nr(leaf, slot)) {
 548                         btrfs_print_leaf(root, leaf);
 549                         printk("slot %d offset bad\n", slot);
 550                         BUG_ON(1);
 551                 }
 552         }
 553         if (slot < nritems - 1) {
 554                 btrfs_item_key(leaf, &leaf_key, slot);
 555                 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
 556                 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
 557                 if (btrfs_item_offset_nr(leaf, slot) !=
 558                         btrfs_item_end_nr(leaf, slot + 1)) {
 559                         btrfs_print_leaf(root, leaf);
 560                         printk("slot %d offset bad\n", slot);
 561                         BUG_ON(1);
 562                 }
 563         }
 564         BUG_ON(btrfs_item_offset_nr(leaf, 0) +
 565                btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
 566         return 0;
 567 }
 568
 569 static int noinline check_block(struct btrfs_root *root,
 570                                 struct btrfs_path *path, int level)
 571 {
 572         return 0;
 573 #if 0
 574         struct extent_buffer *buf = path->nodes[level];
 575
 576         if (memcmp_extent_buffer(buf, root->fs_info->fsid,
 577                                  (unsigned long)btrfs_header_fsid(buf),
 578                                  BTRFS_FSID_SIZE)) {
 579                 printk("warning bad block %Lu\n", buf->start);
 580                 return 1;
 581         }
 582 #endif
 583         if (level == 0)
 584                 return check_leaf(root, path, level);
 585         return check_node(root, path, level);
 586 }
 587
 588 /*
 589  * search for key in the extent_buffer.  The items start at offset p,
 590  * and they are item_size apart.  There are 'max' items in p.
 591  *
 592  * the slot in the array is returned via slot, and it points to
 593  * the place where you would insert key if it is not found in
 594  * the array.
 595  *
 596  * slot may point to max if the key is bigger than all of the keys
 597  */
 598 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
 599                               int item_size, struct btrfs_key *key,
 600                               int max, int *slot)
 601 {
 602         int low = 0;
 603         int high = max;
 604         int mid;
 605         int ret;
 606         struct btrfs_disk_key *tmp = NULL;
 607         struct btrfs_disk_key unaligned;
 608         unsigned long offset;
 609         char *map_token = NULL;
 610         char *kaddr = NULL;
 611         unsigned long map_start = 0;
 612         unsigned long map_len = 0;
 613         int err;
 614
 615         while(low < high) {
 616                 mid = (low + high) / 2;
 617                 offset = p + mid * item_size;
 618
 619                 if (!map_token || offset < map_start ||
 620                     (offset + sizeof(struct btrfs_disk_key)) >
 621                     map_start + map_len) {
 622                         if (map_token) {
 623                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 624                                 map_token = NULL;
 625                         }
 626                         err = map_extent_buffer(eb, offset,
 627                                                 sizeof(struct btrfs_disk_key),
 628                                                 &map_token, &kaddr,
 629                                                 &map_start, &map_len, KM_USER0);
 630
 631                         if (!err) {
 632                                 tmp = (struct btrfs_disk_key *)(kaddr + offset -
 633                                                         map_start);
 634                         } else {
 635                                 read_extent_buffer(eb, &unaligned,
 636                                                    offset, sizeof(unaligned));
 637                                 tmp = &unaligned;
 638                         }
 639
 640                 } else {
 641                         tmp = (struct btrfs_disk_key *)(kaddr + offset -
 642                                                         map_start);
 643                 }
 644                 ret = comp_keys(tmp, key);
 645
 646                 if (ret < 0)
 647                         low = mid + 1;
 648                 else if (ret > 0)
 649                         high = mid;
 650                 else {
 651                         *slot = mid;
 652                         if (map_token)
 653                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 654                         return 0;
 655                 }
 656         }
 657         *slot = low;
 658         if (map_token)
 659                 unmap_extent_buffer(eb, map_token, KM_USER0);
 660         return 1;
 661 }
 662
 663 /*
 664  * simple bin_search frontend that does the right thing for
 665  * leaves vs nodes
 666  */
 667 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
 668                       int level, int *slot)
 669 {
 670         if (level == 0) {
 671                 return generic_bin_search(eb,
 672                                           offsetof(struct btrfs_leaf, items),
 673                                           sizeof(struct btrfs_item),
 674                                           key, btrfs_header_nritems(eb),
 675                                           slot);
 676         } else {
 677                 return generic_bin_search(eb,
 678                                           offsetof(struct btrfs_node, ptrs),
 679                                           sizeof(struct btrfs_key_ptr),
 680                                           key, btrfs_header_nritems(eb),
 681                                           slot);
 682         }
 683         return -1;
 684 }
 685
 686 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
 687                                    struct extent_buffer *parent, int slot)
 688 {
 689         if (slot < 0)
 690                 return NULL;
 691         if (slot >= btrfs_header_nritems(parent))
 692                 return NULL;
 693         return read_tree_block(root, btrfs_node_blockptr(parent, slot),
 694                        btrfs_level_size(root, btrfs_header_level(parent) - 1));
 695 }
 696
 697 static int balance_level(struct btrfs_trans_handle *trans,
 698                          struct btrfs_root *root,
 699                          struct btrfs_path *path, int level)
 700 {
 701         struct extent_buffer *right = NULL;
 702         struct extent_buffer *mid;
 703         struct extent_buffer *left = NULL;
 704         struct extent_buffer *parent = NULL;
 705         int ret = 0;
 706         int wret;
 707         int pslot;
 708         int orig_slot = path->slots[level];
 709         int err_on_enospc = 0;
 710         u64 orig_ptr;
 711
 712         if (level == 0)
 713                 return 0;
 714
 715         mid = path->nodes[level];
 716         WARN_ON(btrfs_header_generation(mid) != trans->transid);
 717
 718         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 719
 720         if (level < BTRFS_MAX_LEVEL - 1)
 721                 parent = path->nodes[level + 1];
 722         pslot = path->slots[level + 1];
 723
 724         /*
 725          * deal with the case where there is only one pointer in the root
 726          * by promoting the node below to a root
 727          */
 728         if (!parent) {
 729                 struct extent_buffer *child;
 730
 731                 if (btrfs_header_nritems(mid) != 1)
 732                         return 0;
 733
 734                 /* promote the child to a root */
 735                 child = read_node_slot(root, mid, 0);
 736                 BUG_ON(!child);
 737                 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
 738                 BUG_ON(ret);
 739
 740                 root->node = child;
 741                 add_root_to_dirty_list(root);
 742                 path->nodes[level] = NULL;
 743                 clean_tree_block(trans, root, mid);
 744                 wait_on_tree_block_writeback(root, mid);
 745                 /* once for the path */
 746                 free_extent_buffer(mid);
 747                 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
 748                                         root->root_key.objectid,
 749                                         btrfs_header_generation(mid), 0, 0, 1);
 750                 /* once for the root ptr */
 751                 free_extent_buffer(mid);
 752                 return ret;
 753         }
 754         if (btrfs_header_nritems(mid) >
 755             BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
 756                 return 0;
 757
 758         if (btrfs_header_nritems(mid) < 2)
 759                 err_on_enospc = 1;
 760
 761         left = read_node_slot(root, parent, pslot - 1);
 762         if (left) {
 763                 wret = btrfs_cow_block(trans, root, left,
 764                                        parent, pslot - 1, &left);
 765                 if (wret) {
 766                         ret = wret;
 767                         goto enospc;
 768                 }
 769         }
 770         right = read_node_slot(root, parent, pslot + 1);
 771         if (right) {
 772                 wret = btrfs_cow_block(trans, root, right,
 773                                        parent, pslot + 1, &right);
 774                 if (wret) {
 775                         ret = wret;
 776                         goto enospc;
 777                 }
 778         }
 779
 780         /* first, try to make some room in the middle buffer */
 781         if (left) {
 782                 orig_slot += btrfs_header_nritems(left);
 783                 wret = push_node_left(trans, root, left, mid);
 784                 if (wret < 0)
 785                         ret = wret;
 786                 if (btrfs_header_nritems(mid) < 2)
 787                         err_on_enospc = 1;
 788         }
 789
 790         /*
 791          * then try to empty the right most buffer into the middle
 792          */
 793         if (right) {
 794                 wret = push_node_left(trans, root, mid, right);
 795                 if (wret < 0 && wret != -ENOSPC)
 796                         ret = wret;
 797                 if (btrfs_header_nritems(right) == 0) {
 798                         u64 bytenr = right->start;
 799                         u64 generation = btrfs_header_generation(parent);
 800                         u32 blocksize = right->len;
 801
 802                         clean_tree_block(trans, root, right);
 803                         wait_on_tree_block_writeback(root, right);
 804                         free_extent_buffer(right);
 805                         right = NULL;
 806                         wret = del_ptr(trans, root, path, level + 1, pslot +
 807                                        1);
 808                         if (wret)
 809                                 ret = wret;
 810                         wret = btrfs_free_extent(trans, root, bytenr,
 811                                                  blocksize,
 812                                                  btrfs_header_owner(parent),
 813                                                  generation, 0, 0, 1);
 814                         if (wret)
 815                                 ret = wret;
 816                 } else {
 817                         struct btrfs_disk_key right_key;
 818                         btrfs_node_key(right, &right_key, 0);
 819                         btrfs_set_node_key(parent, &right_key, pslot + 1);
 820                         btrfs_mark_buffer_dirty(parent);
 821                 }
 822         }
 823         if (btrfs_header_nritems(mid) == 1) {
 824                 /*
 825                  * we're not allowed to leave a node with one item in the
 826                  * tree during a delete.  A deletion from lower in the tree
 827                  * could try to delete the only pointer in this node.
 828                  * So, pull some keys from the left.
 829                  * There has to be a left pointer at this point because
 830                  * otherwise we would have pulled some pointers from the
 831                  * right
 832                  */
 833                 BUG_ON(!left);
 834                 wret = balance_node_right(trans, root, mid, left);
 835                 if (wret < 0) {
 836                         ret = wret;
 837                         goto enospc;
 838                 }
 839                 BUG_ON(wret == 1);
 840         }
 841         if (btrfs_header_nritems(mid) == 0) {
 842                 /* we've managed to empty the middle node, drop it */
 843                 u64 root_gen = btrfs_header_generation(parent);
 844                 u64 bytenr = mid->start;
 845                 u32 blocksize = mid->len;
 846                 clean_tree_block(trans, root, mid);
 847                 wait_on_tree_block_writeback(root, mid);
 848                 free_extent_buffer(mid);
 849                 mid = NULL;
 850                 wret = del_ptr(trans, root, path, level + 1, pslot);
 851                 if (wret)
 852                         ret = wret;
 853                 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
 854                                          btrfs_header_owner(parent),
 855                                          root_gen, 0, 0, 1);
 856                 if (wret)
 857                         ret = wret;
 858         } else {
 859                 /* update the parent key to reflect our changes */
 860                 struct btrfs_disk_key mid_key;
 861                 btrfs_node_key(mid, &mid_key, 0);
 862                 btrfs_set_node_key(parent, &mid_key, pslot);
 863                 btrfs_mark_buffer_dirty(parent);
 864         }
 865
 866         /* update the path */
 867         if (left) {
 868                 if (btrfs_header_nritems(left) > orig_slot) {
 869                         extent_buffer_get(left);
 870                         path->nodes[level] = left;
 871                         path->slots[level + 1] -= 1;
 872                         path->slots[level] = orig_slot;
 873                         if (mid)
 874                                 free_extent_buffer(mid);
 875                 } else {
 876                         orig_slot -= btrfs_header_nritems(left);
 877                         path->slots[level] = orig_slot;
 878                 }
 879         }
 880         /* double check we haven't messed things up */
 881         check_block(root, path, level);
 882         if (orig_ptr !=
 883             btrfs_node_blockptr(path->nodes[level], path->slots[level]))
 884                 BUG();
 885 enospc:
 886         if (right)
 887                 free_extent_buffer(right);
 888         if (left)
 889                 free_extent_buffer(left);
 890         return ret;
 891 }
 892
 893 /* returns zero if the push worked, non-zero otherwise */
 894 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
 895                                           struct btrfs_root *root,
 896                                           struct btrfs_path *path, int level)
 897 {
 898         struct extent_buffer *right = NULL;
 899         struct extent_buffer *mid;
 900         struct extent_buffer *left = NULL;
 901         struct extent_buffer *parent = NULL;
 902         int ret = 0;
 903         int wret;
 904         int pslot;
 905         int orig_slot = path->slots[level];
 906         u64 orig_ptr;
 907
 908         if (level == 0)
 909                 return 1;
 910
 911         mid = path->nodes[level];
 912         WARN_ON(btrfs_header_generation(mid) != trans->transid);
 913         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 914
 915         if (level < BTRFS_MAX_LEVEL - 1)
 916                 parent = path->nodes[level + 1];
 917         pslot = path->slots[level + 1];
 918
 919         if (!parent)
 920                 return 1;
 921
 922         left = read_node_slot(root, parent, pslot - 1);
 923
 924         /* first, try to make some room in the middle buffer */
 925         if (left) {
 926                 u32 left_nr;
 927                 left_nr = btrfs_header_nritems(left);
 928                 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
 929                         wret = 1;
 930                 } else {
 931                         ret = btrfs_cow_block(trans, root, left, parent,
 932                                               pslot - 1, &left);
 933                         if (ret)
 934                                 wret = 1;
 935                         else {
 936                                 wret = push_node_left(trans, root,
 937                                                       left, mid);
 938                         }
 939                 }
 940                 if (wret < 0)
 941                         ret = wret;
 942                 if (wret == 0) {
 943                         struct btrfs_disk_key disk_key;
 944                         orig_slot += left_nr;
 945                         btrfs_node_key(mid, &disk_key, 0);
 946                         btrfs_set_node_key(parent, &disk_key, pslot);
 947                         btrfs_mark_buffer_dirty(parent);
 948                         if (btrfs_header_nritems(left) > orig_slot) {
 949                                 path->nodes[level] = left;
 950                                 path->slots[level + 1] -= 1;
 951                                 path->slots[level] = orig_slot;
 952                                 free_extent_buffer(mid);
 953                         } else {
 954                                 orig_slot -=
 955                                         btrfs_header_nritems(left);
 956                                 path->slots[level] = orig_slot;
 957                                 free_extent_buffer(left);
 958                         }
 959                         return 0;
 960                 }
 961                 free_extent_buffer(left);
 962         }
 963         right= read_node_slot(root, parent, pslot + 1);
 964
 965         /*
 966          * then try to empty the right most buffer into the middle
 967          */
 968         if (right) {
 969                 u32 right_nr;
 970                 right_nr = btrfs_header_nritems(right);
 971                 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
 972                         wret = 1;
 973                 } else {
 974                         ret = btrfs_cow_block(trans, root, right,
 975                                               parent, pslot + 1,
 976                                               &right);
 977                         if (ret)
 978                                 wret = 1;
 979                         else {
 980                                 wret = balance_node_right(trans, root,
 981                                                           right, mid);
 982                         }
 983                 }
 984                 if (wret < 0)
 985                         ret = wret;
 986                 if (wret == 0) {
 987                         struct btrfs_disk_key disk_key;
 988
 989                         btrfs_node_key(right, &disk_key, 0);
 990                         btrfs_set_node_key(parent, &disk_key, pslot + 1);
 991                         btrfs_mark_buffer_dirty(parent);
 992
 993                         if (btrfs_header_nritems(mid) <= orig_slot) {
 994                                 path->nodes[level] = right;
 995                                 path->slots[level + 1] += 1;
 996                                 path->slots[level] = orig_slot -
 997                                         btrfs_header_nritems(mid);
 998                                 free_extent_buffer(mid);
 999                         } else {
1000                                 free_extent_buffer(right);
1001                         }
1002                         return 0;
1003                 }
1004                 free_extent_buffer(right);
1005         }
1006         return 1;
1007 }
1008
1009 /*
1010  * readahead one full node of leaves
1011  */
1012 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
1013                              int level, int slot, u64 objectid)
1014 {
1015         struct extent_buffer *node;
1016         struct btrfs_disk_key disk_key;
1017         u32 nritems;
1018         u64 search;
1019         u64 lowest_read;
1020         u64 highest_read;
1021         u64 nread = 0;
1022         int direction = path->reada;
1023         struct extent_buffer *eb;
1024         u32 nr;
1025         u32 blocksize;
1026         u32 nscan = 0;
1027
1028         if (level != 1)
1029                 return;
1030
1031         if (!path->nodes[level])
1032                 return;
1033
1034         node = path->nodes[level];
1035         search = btrfs_node_blockptr(node, slot);
1036         blocksize = btrfs_level_size(root, level - 1);
1037         eb = btrfs_find_tree_block(root, search, blocksize);
1038         if (eb) {
1039                 free_extent_buffer(eb);
1040                 return;
1041         }
1042
1043         highest_read = search;
1044         lowest_read = search;
1045
1046         nritems = btrfs_header_nritems(node);
1047         nr = slot;
1048         while(1) {
1049                 if (direction < 0) {
1050                         if (nr == 0)
1051                                 break;
1052                         nr--;
1053                 } else if (direction > 0) {
1054                         nr++;
1055                         if (nr >= nritems)
1056                                 break;
1057                 }
1058                 if (path->reada < 0 && objectid) {
1059                         btrfs_node_key(node, &disk_key, nr);
1060                         if (btrfs_disk_key_objectid(&disk_key) != objectid)
1061                                 break;
1062                 }
1063                 search = btrfs_node_blockptr(node, nr);
1064                 if ((search >= lowest_read && search <= highest_read) ||
1065                     (search < lowest_read && lowest_read - search <= 32768) ||
1066                     (search > highest_read && search - highest_read <= 32768)) {
1067                         readahead_tree_block(root, search, blocksize);
1068                         nread += blocksize;
1069                 }
1070                 nscan++;
1071                 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1072                         break;
1073                 if(nread > (1024 * 1024) || nscan > 128)
1074                         break;
1075
1076                 if (search < lowest_read)
1077                         lowest_read = search;
1078                 if (search > highest_read)
1079                         highest_read = search;
1080         }
1081 }
1082 /*
1083  * look for key in the tree.  path is filled in with nodes along the way
1084  * if key is found, we return zero and you can find the item in the leaf
1085  * level of the path (level 0)
1086  *
1087  * If the key isn't found, the path points to the slot where it should
1088  * be inserted, and 1 is returned.  If there are other errors during the
1089  * search a negative error number is returned.
1090  *
1091  * if ins_len > 0, nodes and leaves will be split as we walk down the
1092  * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
1093  * possible)
1094  */
1095 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1096                       *root, struct btrfs_key *key, struct btrfs_path *p, int
1097                       ins_len, int cow)
1098 {
1099         struct extent_buffer *b;
1100         u64 bytenr;
1101         u64 ptr_gen;
1102         int slot;
1103         int ret;
1104         int level;
1105         int should_reada = p->reada;
1106         u8 lowest_level = 0;
1107
1108         lowest_level = p->lowest_level;
1109         WARN_ON(lowest_level && ins_len);
1110         WARN_ON(p->nodes[0] != NULL);
1111         WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1112 again:
1113         b = root->node;
1114         extent_buffer_get(b);
1115         while (b) {
1116                 level = btrfs_header_level(b);
1117                 if (cow) {
1118                         int wret;
1119                         wret = btrfs_cow_block(trans, root, b,
1120                                                p->nodes[level + 1],
1121                                                p->slots[level + 1],
1122                                                &b);
1123                         if (wret) {
1124                                 free_extent_buffer(b);
1125                                 return wret;
1126                         }
1127                 }
1128                 BUG_ON(!cow && ins_len);
1129                 if (level != btrfs_header_level(b))
1130                         WARN_ON(1);
1131                 level = btrfs_header_level(b);
1132                 p->nodes[level] = b;
1133                 ret = check_block(root, p, level);
1134                 if (ret)
1135                         return -1;
1136                 ret = bin_search(b, key, level, &slot);
1137                 if (level != 0) {
1138                         if (ret && slot > 0)
1139                                 slot -= 1;
1140                         p->slots[level] = slot;
1141                         if (ins_len > 0 && btrfs_header_nritems(b) >=
1142                             BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1143                                 int sret = split_node(trans, root, p, level);
1144                                 BUG_ON(sret > 0);
1145                                 if (sret)
1146                                         return sret;
1147                                 b = p->nodes[level];
1148                                 slot = p->slots[level];
1149                         } else if (ins_len < 0) {
1150                                 int sret = balance_level(trans, root, p,
1151                                                          level);
1152                                 if (sret)
1153                                         return sret;
1154                                 b = p->nodes[level];
1155                                 if (!b) {
1156                                         btrfs_release_path(NULL, p);
1157                                         goto again;
1158                                 }
1159                                 slot = p->slots[level];
1160                                 BUG_ON(btrfs_header_nritems(b) == 1);
1161                         }
1162                         /* this is only true while dropping a snapshot */
1163                         if (level == lowest_level)
1164                                 break;
1165                         bytenr = btrfs_node_blockptr(b, slot);
1166                         ptr_gen = btrfs_node_ptr_generation(b, slot);
1167                         if (should_reada)
1168                                 reada_for_search(root, p, level, slot,
1169                                                  key->objectid);
1170                         b = read_tree_block(root, bytenr,
1171                                             btrfs_level_size(root, level - 1));
1172                         if (ptr_gen != btrfs_header_generation(b)) {
1173                                 printk("block %llu bad gen wanted %llu "
1174                                        "found %llu\n",
1175                                 (unsigned long long)b->start,
1176                                 (unsigned long long)ptr_gen,
1177                                 (unsigned long long)btrfs_header_generation(b));
1178                         }
1179                 } else {
1180                         p->slots[level] = slot;
1181                         if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1182                             sizeof(struct btrfs_item) + ins_len) {
1183                                 int sret = split_leaf(trans, root, key,
1184                                                       p, ins_len, ret == 0);
1185                                 BUG_ON(sret > 0);
1186                                 if (sret)
1187                                         return sret;
1188                         }
1189                         return ret;
1190                 }
1191         }
1192         return 1;
1193 }
1194
1195 /*
1196  * adjust the pointers going up the tree, starting at level
1197  * making sure the right key of each node is points to 'key'.
1198  * This is used after shifting pointers to the left, so it stops
1199  * fixing up pointers when a given leaf/node is not in slot 0 of the
1200  * higher levels
1201  *
1202  * If this fails to write a tree block, it returns -1, but continues
1203  * fixing up the blocks in ram so the tree is consistent.
1204  */
1205 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1206                           struct btrfs_root *root, struct btrfs_path *path,
1207                           struct btrfs_disk_key *key, int level)
1208 {
1209         int i;
1210         int ret = 0;
1211         struct extent_buffer *t;
1212
1213         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1214                 int tslot = path->slots[i];
1215                 if (!path->nodes[i])
1216                         break;
1217                 t = path->nodes[i];
1218                 btrfs_set_node_key(t, key, tslot);
1219                 btrfs_mark_buffer_dirty(path->nodes[i]);
1220                 if (tslot != 0)
1221                         break;
1222         }
1223         return ret;
1224 }
1225
1226 /*
1227  * try to push data from one node into the next node left in the
1228  * tree.
1229  *
1230  * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1231  * error, and > 0 if there was no room in the left hand block.
1232  */
1233 static int push_node_left(struct btrfs_trans_handle *trans,
1234                           struct btrfs_root *root, struct extent_buffer *dst,
1235                           struct extent_buffer *src)
1236 {
1237         int push_items = 0;
1238         int src_nritems;
1239         int dst_nritems;
1240         int ret = 0;
1241
1242         src_nritems = btrfs_header_nritems(src);
1243         dst_nritems = btrfs_header_nritems(dst);
1244         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1245         WARN_ON(btrfs_header_generation(src) != trans->transid);
1246         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1247
1248         if (push_items <= 0) {
1249                 return 1;
1250         }
1251
1252         if (src_nritems < push_items)
1253                 push_items = src_nritems;
1254
1255         copy_extent_buffer(dst, src,
1256                            btrfs_node_key_ptr_offset(dst_nritems),
1257                            btrfs_node_key_ptr_offset(0),
1258                            push_items * sizeof(struct btrfs_key_ptr));
1259
1260         if (push_items < src_nritems) {
1261                 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1262                                       btrfs_node_key_ptr_offset(push_items),
1263                                       (src_nritems - push_items) *
1264                                       sizeof(struct btrfs_key_ptr));
1265         }
1266         btrfs_set_header_nritems(src, src_nritems - push_items);
1267         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1268         btrfs_mark_buffer_dirty(src);
1269         btrfs_mark_buffer_dirty(dst);
1270         return ret;
1271 }
1272
1273 /*
1274  * try to push data from one node into the next node right in the
1275  * tree.
1276  *
1277  * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1278  * error, and > 0 if there was no room in the right hand block.
1279  *
1280  * this will  only push up to 1/2 the contents of the left node over
1281  */
1282 static int balance_node_right(struct btrfs_trans_handle *trans,
1283                               struct btrfs_root *root,
1284                               struct extent_buffer *dst,
1285                               struct extent_buffer *src)
1286 {
1287         int push_items = 0;
1288         int max_push;
1289         int src_nritems;
1290         int dst_nritems;
1291         int ret = 0;
1292
1293         WARN_ON(btrfs_header_generation(src) != trans->transid);
1294         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1295
1296         src_nritems = btrfs_header_nritems(src);
1297         dst_nritems = btrfs_header_nritems(dst);
1298         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1299         if (push_items <= 0)
1300                 return 1;
1301
1302         max_push = src_nritems / 2 + 1;
1303         /* don't try to empty the node */
1304         if (max_push >= src_nritems)
1305                 return 1;
1306
1307         if (max_push < push_items)
1308                 push_items = max_push;
1309
1310         memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1311                                       btrfs_node_key_ptr_offset(0),
1312                                       (dst_nritems) *
1313                                       sizeof(struct btrfs_key_ptr));
1314
1315         copy_extent_buffer(dst, src,
1316                            btrfs_node_key_ptr_offset(0),
1317                            btrfs_node_key_ptr_offset(src_nritems - push_items),
1318                            push_items * sizeof(struct btrfs_key_ptr));
1319
1320         btrfs_set_header_nritems(src, src_nritems - push_items);
1321         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1322
1323         btrfs_mark_buffer_dirty(src);
1324         btrfs_mark_buffer_dirty(dst);
1325         return ret;
1326 }
1327
1328 /*
1329  * helper function to insert a new root level in the tree.
1330  * A new node is allocated, and a single item is inserted to
1331  * point to the existing root
1332  *
1333  * returns zero on success or < 0 on failure.
1334  */
1335 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1336                            struct btrfs_root *root,
1337                            struct btrfs_path *path, int level)
1338 {
1339         u64 root_gen;
1340         u64 lower_gen;
1341         struct extent_buffer *lower;
1342         struct extent_buffer *c;
1343         struct btrfs_disk_key lower_key;
1344
1345         BUG_ON(path->nodes[level]);
1346         BUG_ON(path->nodes[level-1] != root->node);
1347
1348         if (root->ref_cows)
1349                 root_gen = trans->transid;
1350         else
1351                 root_gen = 0;
1352
1353         lower = path->nodes[level-1];
1354         if (level == 1)
1355                 btrfs_item_key(lower, &lower_key, 0);
1356         else
1357                 btrfs_node_key(lower, &lower_key, 0);
1358
1359         c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1360                                    root->root_key.objectid,
1361                                    root_gen, lower_key.objectid, level,
1362                                    root->node->start, 0);
1363         if (IS_ERR(c))
1364                 return PTR_ERR(c);
1365         memset_extent_buffer(c, 0, 0, root->nodesize);
1366         btrfs_set_header_nritems(c, 1);
1367         btrfs_set_header_level(c, level);
1368         btrfs_set_header_bytenr(c, c->start);
1369         btrfs_set_header_generation(c, trans->transid);
1370         btrfs_set_header_owner(c, root->root_key.objectid);
1371
1372         write_extent_buffer(c, root->fs_info->fsid,
1373                             (unsigned long)btrfs_header_fsid(c),
1374                             BTRFS_FSID_SIZE);
1375         btrfs_set_node_key(c, &lower_key, 0);
1376         btrfs_set_node_blockptr(c, 0, lower->start);
1377         lower_gen = btrfs_header_generation(lower);
1378         WARN_ON(lower_gen == 0);
1379
1380         btrfs_set_node_ptr_generation(c, 0, lower_gen);
1381
1382         btrfs_mark_buffer_dirty(c);
1383
1384         /* the super has an extra ref to root->node */
1385         free_extent_buffer(root->node);
1386         root->node = c;
1387         add_root_to_dirty_list(root);
1388         extent_buffer_get(c);
1389         path->nodes[level] = c;
1390         path->slots[level] = 0;
1391
1392         if (root->ref_cows && lower_gen != trans->transid) {
1393                 struct btrfs_path *back_path = btrfs_alloc_path();
1394                 int ret;
1395                 ret = btrfs_insert_extent_backref(trans,
1396                                                   root->fs_info->extent_root,
1397                                                   path, lower->start,
1398                                                   root->root_key.objectid,
1399                                                   trans->transid, 0, 0);
1400                 BUG_ON(ret);
1401                 btrfs_free_path(back_path);
1402         }
1403         return 0;
1404 }
1405
1406 /*
1407  * worker function to insert a single pointer in a node.
1408  * the node should have enough room for the pointer already
1409  *
1410  * slot and level indicate where you want the key to go, and
1411  * blocknr is the block the key points to.
1412  *
1413  * returns zero on success and < 0 on any error
1414  */
1415 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1416                       *root, struct btrfs_path *path, struct btrfs_disk_key
1417                       *key, u64 bytenr, int slot, int level)
1418 {
1419         struct extent_buffer *lower;
1420         int nritems;
1421
1422         BUG_ON(!path->nodes[level]);
1423         lower = path->nodes[level];
1424         nritems = btrfs_header_nritems(lower);
1425         if (slot > nritems)
1426                 BUG();
1427         if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1428                 BUG();
1429         if (slot != nritems) {
1430                 memmove_extent_buffer(lower,
1431                               btrfs_node_key_ptr_offset(slot + 1),
1432                               btrfs_node_key_ptr_offset(slot),
1433                               (nritems - slot) * sizeof(struct btrfs_key_ptr));
1434         }
1435         btrfs_set_node_key(lower, key, slot);
1436         btrfs_set_node_blockptr(lower, slot, bytenr);
1437         WARN_ON(trans->transid == 0);
1438         btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1439         btrfs_set_header_nritems(lower, nritems + 1);
1440         btrfs_mark_buffer_dirty(lower);
1441         return 0;
1442 }
1443
1444 /*
1445  * split the node at the specified level in path in two.
1446  * The path is corrected to point to the appropriate node after the split
1447  *
1448  * Before splitting this tries to make some room in the node by pushing
1449  * left and right, if either one works, it returns right away.
1450  *
1451  * returns 0 on success and < 0 on failure
1452  */
1453 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1454                       *root, struct btrfs_path *path, int level)
1455 {
1456         u64 root_gen;
1457         struct extent_buffer *c;
1458         struct extent_buffer *split;
1459         struct btrfs_disk_key disk_key;
1460         int mid;
1461         int ret;
1462         int wret;
1463         u32 c_nritems;
1464
1465         c = path->nodes[level];
1466         WARN_ON(btrfs_header_generation(c) != trans->transid);
1467         if (c == root->node) {
1468                 /* trying to split the root, lets make a new one */
1469                 ret = insert_new_root(trans, root, path, level + 1);
1470                 if (ret)
1471                         return ret;
1472         } else {
1473                 ret = push_nodes_for_insert(trans, root, path, level);
1474                 c = path->nodes[level];
1475                 if (!ret && btrfs_header_nritems(c) <
1476                     BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1477                         return 0;
1478                 if (ret < 0)
1479                         return ret;
1480         }
1481
1482         c_nritems = btrfs_header_nritems(c);
1483         if (root->ref_cows)
1484                 root_gen = trans->transid;
1485         else
1486                 root_gen = 0;
1487
1488         btrfs_node_key(c, &disk_key, 0);
1489         split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1490                                          root->root_key.objectid,
1491                                          root_gen,
1492                                          btrfs_disk_key_objectid(&disk_key),
1493                                          level, c->start, 0);
1494         if (IS_ERR(split))
1495                 return PTR_ERR(split);
1496
1497         btrfs_set_header_flags(split, btrfs_header_flags(c));
1498         btrfs_set_header_level(split, btrfs_header_level(c));
1499         btrfs_set_header_bytenr(split, split->start);
1500         btrfs_set_header_generation(split, trans->transid);
1501         btrfs_set_header_owner(split, root->root_key.objectid);
1502         btrfs_set_header_flags(split, 0);
1503         write_extent_buffer(split, root->fs_info->fsid,
1504                             (unsigned long)btrfs_header_fsid(split),
1505                             BTRFS_FSID_SIZE);
1506
1507         mid = (c_nritems + 1) / 2;
1508
1509         copy_extent_buffer(split, c,
1510                            btrfs_node_key_ptr_offset(0),
1511                            btrfs_node_key_ptr_offset(mid),
1512                            (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1513         btrfs_set_header_nritems(split, c_nritems - mid);
1514         btrfs_set_header_nritems(c, mid);
1515         ret = 0;
1516
1517         btrfs_mark_buffer_dirty(c);
1518         btrfs_mark_buffer_dirty(split);
1519
1520         btrfs_node_key(split, &disk_key, 0);
1521         wret = insert_ptr(trans, root, path, &disk_key, split->start,
1522                           path->slots[level + 1] + 1,
1523                           level + 1);
1524         if (wret)
1525                 ret = wret;
1526
1527         if (path->slots[level] >= mid) {
1528                 path->slots[level] -= mid;
1529                 free_extent_buffer(c);
1530                 path->nodes[level] = split;
1531                 path->slots[level + 1] += 1;
1532         } else {
1533                 free_extent_buffer(split);
1534         }
1535         return ret;
1536 }
1537
1538 /*
1539  * how many bytes are required to store the items in a leaf.  start
1540  * and nr indicate which items in the leaf to check.  This totals up the
1541  * space used both by the item structs and the item data
1542  */
1543 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1544 {
1545         int data_len;
1546         int nritems = btrfs_header_nritems(l);
1547         int end = min(nritems, start + nr) - 1;
1548
1549         if (!nr)
1550                 return 0;
1551         data_len = btrfs_item_end_nr(l, start);
1552         data_len = data_len - btrfs_item_offset_nr(l, end);
1553         data_len += sizeof(struct btrfs_item) * nr;
1554         WARN_ON(data_len < 0);
1555         return data_len;
1556 }
1557
1558 /*
1559  * The space between the end of the leaf items and
1560  * the start of the leaf data.  IOW, how much room
1561  * the leaf has left for both items and data
1562  */
1563 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1564 {
1565         int nritems = btrfs_header_nritems(leaf);
1566         int ret;
1567         ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1568         if (ret < 0) {
1569                 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1570                        ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1571                        leaf_space_used(leaf, 0, nritems), nritems);
1572         }
1573         return ret;
1574 }
1575
1576 /*
1577  * push some data in the path leaf to the right, trying to free up at
1578  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1579  *
1580  * returns 1 if the push failed because the other node didn't have enough
1581  * room, 0 if everything worked out and < 0 if there were major errors.
1582  */
1583 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1584                            *root, struct btrfs_path *path, int data_size,
1585                            int empty)
1586 {
1587         struct extent_buffer *left = path->nodes[0];
1588         struct extent_buffer *right;
1589         struct extent_buffer *upper;
1590         struct btrfs_disk_key disk_key;
1591         int slot;
1592         u32 i;
1593         int free_space;
1594         int push_space = 0;
1595         int push_items = 0;
1596         struct btrfs_item *item;
1597         u32 left_nritems;
1598         u32 nr;
1599         u32 right_nritems;
1600         u32 data_end;
1601         u32 this_item_size;
1602         int ret;
1603
1604         slot = path->slots[1];
1605         if (!path->nodes[1]) {
1606                 return 1;
1607         }
1608         upper = path->nodes[1];
1609         if (slot >= btrfs_header_nritems(upper) - 1)
1610                 return 1;
1611
1612         right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1613                                 root->leafsize);
1614         free_space = btrfs_leaf_free_space(root, right);
1615         if (free_space < data_size + sizeof(struct btrfs_item)) {
1616                 free_extent_buffer(right);
1617                 return 1;
1618         }
1619
1620         /* cow and double check */
1621         ret = btrfs_cow_block(trans, root, right, upper,
1622                               slot + 1, &right);
1623         if (ret) {
1624                 free_extent_buffer(right);
1625                 return 1;
1626         }
1627         free_space = btrfs_leaf_free_space(root, right);
1628         if (free_space < data_size + sizeof(struct btrfs_item)) {
1629                 free_extent_buffer(right);
1630                 return 1;
1631         }
1632
1633         left_nritems = btrfs_header_nritems(left);
1634         if (left_nritems == 0) {
1635                 free_extent_buffer(right);
1636                 return 1;
1637         }
1638
1639         if (empty)
1640                 nr = 0;
1641         else
1642                 nr = 1;
1643
1644         i = left_nritems - 1;
1645         while (i >= nr) {
1646                 item = btrfs_item_nr(left, i);
1647
1648                 if (path->slots[0] == i)
1649                         push_space += data_size + sizeof(*item);
1650
1651                 if (!left->map_token) {
1652                         map_extent_buffer(left, (unsigned long)item,
1653                                         sizeof(struct btrfs_item),
1654                                         &left->map_token, &left->kaddr,
1655                                         &left->map_start, &left->map_len,
1656                                         KM_USER1);
1657                 }
1658
1659                 this_item_size = btrfs_item_size(left, item);
1660                 if (this_item_size + sizeof(*item) + push_space > free_space)
1661                         break;
1662                 push_items++;
1663                 push_space += this_item_size + sizeof(*item);
1664                 if (i == 0)
1665                         break;
1666                 i--;
1667         }
1668         if (left->map_token) {
1669                 unmap_extent_buffer(left, left->map_token, KM_USER1);
1670                 left->map_token = NULL;
1671         }
1672
1673         if (push_items == 0) {
1674                 free_extent_buffer(right);
1675                 return 1;
1676         }
1677
1678         if (!empty && push_items == left_nritems)
1679                 WARN_ON(1);
1680
1681         /* push left to right */
1682         right_nritems = btrfs_header_nritems(right);
1683
1684         push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1685         push_space -= leaf_data_end(root, left);
1686
1687         /* make room in the right data area */
1688         data_end = leaf_data_end(root, right);
1689         memmove_extent_buffer(right,
1690                               btrfs_leaf_data(right) + data_end - push_space,
1691                               btrfs_leaf_data(right) + data_end,
1692                               BTRFS_LEAF_DATA_SIZE(root) - data_end);
1693
1694         /* copy from the left data area */
1695         copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1696                      BTRFS_LEAF_DATA_SIZE(root) - push_space,
1697                      btrfs_leaf_data(left) + leaf_data_end(root, left),
1698                      push_space);
1699
1700         memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1701                               btrfs_item_nr_offset(0),
1702                               right_nritems * sizeof(struct btrfs_item));
1703
1704         /* copy the items from left to right */
1705         copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1706                    btrfs_item_nr_offset(left_nritems - push_items),
1707                    push_items * sizeof(struct btrfs_item));
1708
1709         /* update the item pointers */
1710         right_nritems += push_items;
1711         btrfs_set_header_nritems(right, right_nritems);
1712         push_space = BTRFS_LEAF_DATA_SIZE(root);
1713         for (i = 0; i < right_nritems; i++) {
1714                 item = btrfs_item_nr(right, i);
1715                 if (!right->map_token) {
1716                         map_extent_buffer(right, (unsigned long)item,
1717                                         sizeof(struct btrfs_item),
1718                                         &right->map_token, &right->kaddr,
1719                                         &right->map_start, &right->map_len,
1720                                         KM_USER1);
1721                 }
1722                 push_space -= btrfs_item_size(right, item);
1723                 btrfs_set_item_offset(right, item, push_space);
1724         }
1725
1726         if (right->map_token) {
1727                 unmap_extent_buffer(right, right->map_token, KM_USER1);
1728                 right->map_token = NULL;
1729         }
1730         left_nritems -= push_items;
1731         btrfs_set_header_nritems(left, left_nritems);
1732
1733         if (left_nritems)
1734                 btrfs_mark_buffer_dirty(left);
1735         btrfs_mark_buffer_dirty(right);
1736
1737         btrfs_item_key(right, &disk_key, 0);
1738         btrfs_set_node_key(upper, &disk_key, slot + 1);
1739         btrfs_mark_buffer_dirty(upper);
1740
1741         /* then fixup the leaf pointer in the path */
1742         if (path->slots[0] >= left_nritems) {
1743                 path->slots[0] -= left_nritems;
1744                 free_extent_buffer(path->nodes[0]);
1745                 path->nodes[0] = right;
1746                 path->slots[1] += 1;
1747         } else {
1748                 free_extent_buffer(right);
1749         }
1750         return 0;
1751 }
1752 /*
1753  * push some data in the path leaf to the left, trying to free up at
1754  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1755  */
1756 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1757                           *root, struct btrfs_path *path, int data_size,
1758                           int empty)
1759 {
1760         struct btrfs_disk_key disk_key;
1761         struct extent_buffer *right = path->nodes[0];
1762         struct extent_buffer *left;
1763         int slot;
1764         int i;
1765         int free_space;
1766         int push_space = 0;
1767         int push_items = 0;
1768         struct btrfs_item *item;
1769         u32 old_left_nritems;
1770         u32 right_nritems;
1771         u32 nr;
1772         int ret = 0;
1773         int wret;
1774         u32 this_item_size;
1775         u32 old_left_item_size;
1776
1777         slot = path->slots[1];
1778         if (slot == 0)
1779                 return 1;
1780         if (!path->nodes[1])
1781                 return 1;
1782
1783         right_nritems = btrfs_header_nritems(right);
1784         if (right_nritems == 0) {
1785                 return 1;
1786         }
1787
1788         left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1789                                slot - 1), root->leafsize);
1790         free_space = btrfs_leaf_free_space(root, left);
1791         if (free_space < data_size + sizeof(struct btrfs_item)) {
1792                 free_extent_buffer(left);
1793                 return 1;
1794         }
1795
1796         /* cow and double check */
1797         ret = btrfs_cow_block(trans, root, left,
1798                               path->nodes[1], slot - 1, &left);
1799         if (ret) {
1800                 /* we hit -ENOSPC, but it isn't fatal here */
1801                 free_extent_buffer(left);
1802                 return 1;
1803         }
1804
1805         free_space = btrfs_leaf_free_space(root, left);
1806         if (free_space < data_size + sizeof(struct btrfs_item)) {
1807                 free_extent_buffer(left);
1808                 return 1;
1809         }
1810
1811         if (empty)
1812                 nr = right_nritems;
1813         else
1814                 nr = right_nritems - 1;
1815
1816         for (i = 0; i < nr; i++) {
1817                 item = btrfs_item_nr(right, i);
1818                 if (!right->map_token) {
1819                         map_extent_buffer(right, (unsigned long)item,
1820                                         sizeof(struct btrfs_item),
1821                                         &right->map_token, &right->kaddr,
1822                                         &right->map_start, &right->map_len,
1823                                         KM_USER1);
1824                 }
1825
1826                 if (path->slots[0] == i)
1827                         push_space += data_size + sizeof(*item);
1828
1829                 this_item_size = btrfs_item_size(right, item);
1830                 if (this_item_size + sizeof(*item) + push_space > free_space)
1831                         break;
1832
1833                 push_items++;
1834                 push_space += this_item_size + sizeof(*item);
1835         }
1836
1837         if (right->map_token) {
1838                 unmap_extent_buffer(right, right->map_token, KM_USER1);
1839                 right->map_token = NULL;
1840         }
1841
1842         if (push_items == 0) {
1843                 free_extent_buffer(left);
1844                 return 1;
1845         }
1846         if (!empty && push_items == btrfs_header_nritems(right))
1847                 WARN_ON(1);
1848
1849         /* push data from right to left */
1850         copy_extent_buffer(left, right,
1851                            btrfs_item_nr_offset(btrfs_header_nritems(left)),
1852                            btrfs_item_nr_offset(0),
1853                            push_items * sizeof(struct btrfs_item));
1854
1855         push_space = BTRFS_LEAF_DATA_SIZE(root) -
1856                      btrfs_item_offset_nr(right, push_items -1);
1857
1858         copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1859                      leaf_data_end(root, left) - push_space,
1860                      btrfs_leaf_data(right) +
1861                      btrfs_item_offset_nr(right, push_items - 1),
1862                      push_space);
1863         old_left_nritems = btrfs_header_nritems(left);
1864         BUG_ON(old_left_nritems < 0);
1865
1866         old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1867         for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1868                 u32 ioff;
1869
1870                 item = btrfs_item_nr(left, i);
1871                 if (!left->map_token) {
1872                         map_extent_buffer(left, (unsigned long)item,
1873                                         sizeof(struct btrfs_item),
1874                                         &left->map_token, &left->kaddr,
1875                                         &left->map_start, &left->map_len,
1876                                         KM_USER1);
1877                 }
1878
1879                 ioff = btrfs_item_offset(left, item);
1880                 btrfs_set_item_offset(left, item,
1881                       ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1882         }
1883         btrfs_set_header_nritems(left, old_left_nritems + push_items);
1884         if (left->map_token) {
1885                 unmap_extent_buffer(left, left->map_token, KM_USER1);
1886                 left->map_token = NULL;
1887         }
1888
1889         /* fixup right node */
1890         if (push_items > right_nritems) {
1891                 printk("push items %d nr %u\n", push_items, right_nritems);
1892                 WARN_ON(1);
1893         }
1894
1895         if (push_items < right_nritems) {
1896                 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1897                                                   leaf_data_end(root, right);
1898                 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1899                                       BTRFS_LEAF_DATA_SIZE(root) - push_space,
1900                                       btrfs_leaf_data(right) +
1901                                       leaf_data_end(root, right), push_space);
1902
1903                 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1904                               btrfs_item_nr_offset(push_items),
1905                              (btrfs_header_nritems(right) - push_items) *
1906                              sizeof(struct btrfs_item));
1907         }
1908         right_nritems -= push_items;
1909         btrfs_set_header_nritems(right, right_nritems);
1910         push_space = BTRFS_LEAF_DATA_SIZE(root);
1911         for (i = 0; i < right_nritems; i++) {
1912                 item = btrfs_item_nr(right, i);
1913
1914                 if (!right->map_token) {
1915                         map_extent_buffer(right, (unsigned long)item,
1916                                         sizeof(struct btrfs_item),
1917                                         &right->map_token, &right->kaddr,
1918                                         &right->map_start, &right->map_len,
1919                                         KM_USER1);
1920                 }
1921
1922                 push_space = push_space - btrfs_item_size(right, item);
1923                 btrfs_set_item_offset(right, item, push_space);
1924         }
1925         if (right->map_token) {
1926                 unmap_extent_buffer(right, right->map_token, KM_USER1);
1927                 right->map_token = NULL;
1928         }
1929
1930         btrfs_mark_buffer_dirty(left);
1931         if (right_nritems)
1932                 btrfs_mark_buffer_dirty(right);
1933
1934         btrfs_item_key(right, &disk_key, 0);
1935         wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1936         if (wret)
1937                 ret = wret;
1938
1939         /* then fixup the leaf pointer in the path */
1940         if (path->slots[0] < push_items) {
1941                 path->slots[0] += old_left_nritems;
1942                 free_extent_buffer(path->nodes[0]);
1943                 path->nodes[0] = left;
1944                 path->slots[1] -= 1;
1945         } else {
1946                 free_extent_buffer(left);
1947                 path->slots[0] -= push_items;
1948         }
1949         BUG_ON(path->slots[0] < 0);
1950         return ret;
1951 }
1952
1953 /*
1954  * split the path's leaf in two, making sure there is at least data_size
1955  * available for the resulting leaf level of the path.
1956  *
1957  * returns 0 if all went well and < 0 on failure.
1958  */
1959 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1960                       *root, struct btrfs_key *ins_key,
1961                       struct btrfs_path *path, int data_size, int extend)
1962 {
1963         u64 root_gen;
1964         struct extent_buffer *l;
1965         u32 nritems;
1966         int mid;
1967         int slot;
1968         struct extent_buffer *right;
1969         int space_needed = data_size + sizeof(struct btrfs_item);
1970         int data_copy_size;
1971         int rt_data_off;
1972         int i;
1973         int ret = 0;
1974         int wret;
1975         int double_split;
1976         int num_doubles = 0;
1977         struct btrfs_disk_key disk_key;
1978
1979         if (extend)
1980                 space_needed = data_size;
1981
1982         if (root->ref_cows)
1983                 root_gen = trans->transid;
1984         else
1985                 root_gen = 0;
1986
1987         /* first try to make some room by pushing left and right */
1988         if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1989                 wret = push_leaf_right(trans, root, path, data_size, 0);
1990                 if (wret < 0) {
1991                         return wret;
1992                 }
1993                 if (wret) {
1994                         wret = push_leaf_left(trans, root, path, data_size, 0);
1995                         if (wret < 0)
1996                                 return wret;
1997                 }
1998                 l = path->nodes[0];
1999
2000                 /* did the pushes work? */
2001                 if (btrfs_leaf_free_space(root, l) >= space_needed)
2002                         return 0;
2003         }
2004
2005         if (!path->nodes[1]) {
2006                 ret = insert_new_root(trans, root, path, 1);
2007                 if (ret)
2008                         return ret;
2009         }
2010 again:
2011         double_split = 0;
2012         l = path->nodes[0];
2013         slot = path->slots[0];
2014         nritems = btrfs_header_nritems(l);
2015         mid = (nritems + 1)/ 2;
2016
2017         btrfs_item_key(l, &disk_key, 0);
2018
2019         right = __btrfs_alloc_free_block(trans, root, root->leafsize,
2020                                          root->root_key.objectid,
2021                                          root_gen, disk_key.objectid, 0,
2022                                          l->start, 0);
2023         if (IS_ERR(right)) {
2024                 BUG_ON(1);
2025                 return PTR_ERR(right);
2026         }
2027
2028         memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2029         btrfs_set_header_bytenr(right, right->start);
2030         btrfs_set_header_generation(right, trans->transid);
2031         btrfs_set_header_owner(right, root->root_key.objectid);
2032         btrfs_set_header_level(right, 0);
2033         write_extent_buffer(right, root->fs_info->fsid,
2034                             (unsigned long)btrfs_header_fsid(right),
2035                             BTRFS_FSID_SIZE);
2036         if (mid <= slot) {
2037                 if (nritems == 1 ||
2038                     leaf_space_used(l, mid, nritems - mid) + space_needed >
2039                         BTRFS_LEAF_DATA_SIZE(root)) {
2040                         if (slot >= nritems) {
2041                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2042                                 btrfs_set_header_nritems(right, 0);
2043                                 wret = insert_ptr(trans, root, path,
2044                                                   &disk_key, right->start,
2045                                                   path->slots[1] + 1, 1);
2046                                 if (wret)
2047                                         ret = wret;
2048                                 free_extent_buffer(path->nodes[0]);
2049                                 path->nodes[0] = right;
2050                                 path->slots[0] = 0;
2051                                 path->slots[1] += 1;
2052                                 btrfs_mark_buffer_dirty(right);
2053                                 return ret;
2054                         }
2055                         mid = slot;
2056                         if (mid != nritems &&
2057                             leaf_space_used(l, mid, nritems - mid) +
2058                             space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2059                                 double_split = 1;
2060                         }
2061                 }
2062         } else {
2063                 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2064                         BTRFS_LEAF_DATA_SIZE(root)) {
2065                         if (!extend && slot == 0) {
2066                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2067                                 btrfs_set_header_nritems(right, 0);
2068                                 wret = insert_ptr(trans, root, path,
2069                                                   &disk_key,
2070                                                   right->start,
2071                                                   path->slots[1], 1);
2072                                 if (wret)
2073                                         ret = wret;
2074                                 free_extent_buffer(path->nodes[0]);
2075                                 path->nodes[0] = right;
2076                                 path->slots[0] = 0;
2077                                 if (path->slots[1] == 0) {
2078                                         wret = fixup_low_keys(trans, root,
2079                                                    path, &disk_key, 1);
2080                                         if (wret)
2081                                                 ret = wret;
2082                                 }
2083                                 btrfs_mark_buffer_dirty(right);
2084                                 return ret;
2085                         } else if (extend && slot == 0) {
2086                                 mid = 1;
2087                         } else {
2088                                 mid = slot;
2089                                 if (mid != nritems &&
2090                                     leaf_space_used(l, mid, nritems - mid) +
2091                                     space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2092                                         double_split = 1;
2093                                 }
2094                         }
2095                 }
2096         }
2097         nritems = nritems - mid;
2098         btrfs_set_header_nritems(right, nritems);
2099         data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2100
2101         copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2102                            btrfs_item_nr_offset(mid),
2103                            nritems * sizeof(struct btrfs_item));
2104
2105         copy_extent_buffer(right, l,
2106                      btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2107                      data_copy_size, btrfs_leaf_data(l) +
2108                      leaf_data_end(root, l), data_copy_size);
2109
2110         rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2111                       btrfs_item_end_nr(l, mid);
2112
2113         for (i = 0; i < nritems; i++) {
2114                 struct btrfs_item *item = btrfs_item_nr(right, i);
2115                 u32 ioff;
2116
2117                 if (!right->map_token) {
2118                         map_extent_buffer(right, (unsigned long)item,
2119                                         sizeof(struct btrfs_item),
2120                                         &right->map_token, &right->kaddr,
2121                                         &right->map_start, &right->map_len,
2122                                         KM_USER1);
2123                 }
2124
2125                 ioff = btrfs_item_offset(right, item);
2126                 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2127         }
2128
2129         if (right->map_token) {
2130                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2131                 right->map_token = NULL;
2132         }
2133
2134         btrfs_set_header_nritems(l, mid);
2135         ret = 0;
2136         btrfs_item_key(right, &disk_key, 0);
2137         wret = insert_ptr(trans, root, path, &disk_key, right->start,
2138                           path->slots[1] + 1, 1);
2139         if (wret)
2140                 ret = wret;
2141
2142         btrfs_mark_buffer_dirty(right);
2143         btrfs_mark_buffer_dirty(l);
2144         BUG_ON(path->slots[0] != slot);
2145
2146         if (mid <= slot) {
2147                 free_extent_buffer(path->nodes[0]);
2148                 path->nodes[0] = right;
2149                 path->slots[0] -= mid;
2150                 path->slots[1] += 1;
2151         } else
2152                 free_extent_buffer(right);
2153
2154         BUG_ON(path->slots[0] < 0);
2155
2156         if (double_split) {
2157                 BUG_ON(num_doubles != 0);
2158                 num_doubles++;
2159                 goto again;
2160         }
2161         return ret;
2162 }
2163
2164 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2165                         struct btrfs_root *root,
2166                         struct btrfs_path *path,
2167                         u32 new_size, int from_end)
2168 {
2169         int ret = 0;
2170         int slot;
2171         int slot_orig;
2172         struct extent_buffer *leaf;
2173         struct btrfs_item *item;
2174         u32 nritems;
2175         unsigned int data_end;
2176         unsigned int old_data_start;
2177         unsigned int old_size;
2178         unsigned int size_diff;
2179         int i;
2180
2181         slot_orig = path->slots[0];
2182         leaf = path->nodes[0];
2183         slot = path->slots[0];
2184
2185         old_size = btrfs_item_size_nr(leaf, slot);
2186         if (old_size == new_size)
2187                 return 0;
2188
2189         nritems = btrfs_header_nritems(leaf);
2190         data_end = leaf_data_end(root, leaf);
2191
2192         old_data_start = btrfs_item_offset_nr(leaf, slot);
2193
2194         size_diff = old_size - new_size;
2195
2196         BUG_ON(slot < 0);
2197         BUG_ON(slot >= nritems);
2198
2199         /*
2200          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2201          */
2202         /* first correct the data pointers */
2203         for (i = slot; i < nritems; i++) {
2204                 u32 ioff;
2205                 item = btrfs_item_nr(leaf, i);
2206
2207                 if (!leaf->map_token) {
2208                         map_extent_buffer(leaf, (unsigned long)item,
2209                                         sizeof(struct btrfs_item),
2210                                         &leaf->map_token, &leaf->kaddr,
2211                                         &leaf->map_start, &leaf->map_len,
2212                                         KM_USER1);
2213                 }
2214
2215                 ioff = btrfs_item_offset(leaf, item);
2216                 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2217         }
2218
2219         if (leaf->map_token) {
2220                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2221                 leaf->map_token = NULL;
2222         }
2223
2224         /* shift the data */
2225         if (from_end) {
2226                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2227                               data_end + size_diff, btrfs_leaf_data(leaf) +
2228                               data_end, old_data_start + new_size - data_end);
2229         } else {
2230                 struct btrfs_disk_key disk_key;
2231                 u64 offset;
2232
2233                 btrfs_item_key(leaf, &disk_key, slot);
2234
2235                 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2236                         unsigned long ptr;
2237                         struct btrfs_file_extent_item *fi;
2238
2239                         fi = btrfs_item_ptr(leaf, slot,
2240                                             struct btrfs_file_extent_item);
2241                         fi = (struct btrfs_file_extent_item *)(
2242                              (unsigned long)fi - size_diff);
2243
2244                         if (btrfs_file_extent_type(leaf, fi) ==
2245                             BTRFS_FILE_EXTENT_INLINE) {
2246                                 ptr = btrfs_item_ptr_offset(leaf, slot);
2247                                 memmove_extent_buffer(leaf, ptr,
2248                                         (unsigned long)fi,
2249                                         offsetof(struct btrfs_file_extent_item,
2250                                                  disk_bytenr));
2251                         }
2252                 }
2253
2254                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2255                               data_end + size_diff, btrfs_leaf_data(leaf) +
2256                               data_end, old_data_start - data_end);
2257
2258                 offset = btrfs_disk_key_offset(&disk_key);
2259                 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2260                 btrfs_set_item_key(leaf, &disk_key, slot);
2261                 if (slot == 0)
2262                         fixup_low_keys(trans, root, path, &disk_key, 1);
2263         }
2264
2265         item = btrfs_item_nr(leaf, slot);
2266         btrfs_set_item_size(leaf, item, new_size);
2267         btrfs_mark_buffer_dirty(leaf);
2268
2269         ret = 0;
2270         if (btrfs_leaf_free_space(root, leaf) < 0) {
2271                 btrfs_print_leaf(root, leaf);
2272                 BUG();
2273         }
2274         return ret;
2275 }
2276
2277 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2278                       struct btrfs_root *root, struct btrfs_path *path,
2279                       u32 data_size)
2280 {
2281         int ret = 0;
2282         int slot;
2283         int slot_orig;
2284         struct extent_buffer *leaf;
2285         struct btrfs_item *item;
2286         u32 nritems;
2287         unsigned int data_end;
2288         unsigned int old_data;
2289         unsigned int old_size;
2290         int i;
2291
2292         slot_orig = path->slots[0];
2293         leaf = path->nodes[0];
2294
2295         nritems = btrfs_header_nritems(leaf);
2296         data_end = leaf_data_end(root, leaf);
2297
2298         if (btrfs_leaf_free_space(root, leaf) < data_size) {
2299                 btrfs_print_leaf(root, leaf);
2300                 BUG();
2301         }
2302         slot = path->slots[0];
2303         old_data = btrfs_item_end_nr(leaf, slot);
2304
2305         BUG_ON(slot < 0);
2306         if (slot >= nritems) {
2307                 btrfs_print_leaf(root, leaf);
2308                 printk("slot %d too large, nritems %d\n", slot, nritems);
2309                 BUG_ON(1);
2310         }
2311
2312         /*
2313          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2314          */
2315         /* first correct the data pointers */
2316         for (i = slot; i < nritems; i++) {
2317                 u32 ioff;
2318                 item = btrfs_item_nr(leaf, i);
2319
2320                 if (!leaf->map_token) {
2321                         map_extent_buffer(leaf, (unsigned long)item,
2322                                         sizeof(struct btrfs_item),
2323                                         &leaf->map_token, &leaf->kaddr,
2324                                         &leaf->map_start, &leaf->map_len,
2325                                         KM_USER1);
2326                 }
2327                 ioff = btrfs_item_offset(leaf, item);
2328                 btrfs_set_item_offset(leaf, item, ioff - data_size);
2329         }
2330
2331         if (leaf->map_token) {
2332                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2333                 leaf->map_token = NULL;
2334         }
2335
2336         /* shift the data */
2337         memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2338                       data_end - data_size, btrfs_leaf_data(leaf) +
2339                       data_end, old_data - data_end);
2340
2341         data_end = old_data;
2342         old_size = btrfs_item_size_nr(leaf, slot);
2343         item = btrfs_item_nr(leaf, slot);
2344         btrfs_set_item_size(leaf, item, old_size + data_size);
2345         btrfs_mark_buffer_dirty(leaf);
2346
2347         ret = 0;
2348         if (btrfs_leaf_free_space(root, leaf) < 0) {
2349                 btrfs_print_leaf(root, leaf);
2350                 BUG();
2351         }
2352         return ret;
2353 }
2354
2355 /*
2356  * Given a key and some data, insert an item into the tree.
2357  * This does all the path init required, making room in the tree if needed.
2358  */
2359 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2360                             struct btrfs_root *root,
2361                             struct btrfs_path *path,
2362                             struct btrfs_key *cpu_key, u32 *data_size,
2363                             int nr)
2364 {
2365         struct extent_buffer *leaf;
2366         struct btrfs_item *item;
2367         int ret = 0;
2368         int slot;
2369         int slot_orig;
2370         int i;
2371         u32 nritems;
2372         u32 total_size = 0;
2373         u32 total_data = 0;
2374         unsigned int data_end;
2375         struct btrfs_disk_key disk_key;
2376
2377         for (i = 0; i < nr; i++) {
2378                 total_data += data_size[i];
2379         }
2380
2381         /* create a root if there isn't one */
2382         if (!root->node)
2383                 BUG();
2384
2385         total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2386         ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2387         if (ret == 0) {
2388                 return -EEXIST;
2389         }
2390         if (ret < 0)
2391                 goto out;
2392
2393         slot_orig = path->slots[0];
2394         leaf = path->nodes[0];
2395
2396         nritems = btrfs_header_nritems(leaf);
2397         data_end = leaf_data_end(root, leaf);
2398
2399         if (btrfs_leaf_free_space(root, leaf) <
2400             sizeof(struct btrfs_item) + total_size) {
2401                 btrfs_print_leaf(root, leaf);
2402                 printk("not enough freespace need %u have %d\n",
2403                        total_size, btrfs_leaf_free_space(root, leaf));
2404                 BUG();
2405         }
2406
2407         slot = path->slots[0];
2408         BUG_ON(slot < 0);
2409
2410         if (slot != nritems) {
2411                 int i;
2412                 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2413
2414                 if (old_data < data_end) {
2415                         btrfs_print_leaf(root, leaf);
2416                         printk("slot %d old_data %d data_end %d\n",
2417                                slot, old_data, data_end);
2418                         BUG_ON(1);
2419                 }
2420                 /*
2421                  * item0..itemN ... dataN.offset..dataN.size .. data0.size
2422                  */
2423                 /* first correct the data pointers */
2424                 WARN_ON(leaf->map_token);
2425                 for (i = slot; i < nritems; i++) {
2426                         u32 ioff;
2427
2428                         item = btrfs_item_nr(leaf, i);
2429                         if (!leaf->map_token) {
2430                                 map_extent_buffer(leaf, (unsigned long)item,
2431                                         sizeof(struct btrfs_item),
2432                                         &leaf->map_token, &leaf->kaddr,
2433                                         &leaf->map_start, &leaf->map_len,
2434                                         KM_USER1);
2435                         }
2436
2437                         ioff = btrfs_item_offset(leaf, item);
2438                         btrfs_set_item_offset(leaf, item, ioff - total_data);
2439                 }
2440                 if (leaf->map_token) {
2441                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2442                         leaf->map_token = NULL;
2443                 }
2444
2445                 /* shift the items */
2446                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2447                               btrfs_item_nr_offset(slot),
2448                               (nritems - slot) * sizeof(struct btrfs_item));
2449
2450                 /* shift the data */
2451                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2452                               data_end - total_data, btrfs_leaf_data(leaf) +
2453                               data_end, old_data - data_end);
2454                 data_end = old_data;
2455         }
2456
2457         /* setup the item for the new data */
2458         for (i = 0; i < nr; i++) {
2459                 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2460                 btrfs_set_item_key(leaf, &disk_key, slot + i);
2461                 item = btrfs_item_nr(leaf, slot + i);
2462                 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2463                 data_end -= data_size[i];
2464                 btrfs_set_item_size(leaf, item, data_size[i]);
2465         }
2466         btrfs_set_header_nritems(leaf, nritems + nr);
2467         btrfs_mark_buffer_dirty(leaf);
2468
2469         ret = 0;
2470         if (slot == 0) {
2471                 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2472                 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2473         }
2474
2475         if (btrfs_leaf_free_space(root, leaf) < 0) {
2476                 btrfs_print_leaf(root, leaf);
2477                 BUG();
2478         }
2479
2480 out:
2481         return ret;
2482 }
2483
2484 /*
2485  * Given a key and some data, insert an item into the tree.
2486  * This does all the path init required, making room in the tree if needed.
2487  */
2488 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2489                       *root, struct btrfs_key *cpu_key, void *data, u32
2490                       data_size)
2491 {
2492         int ret = 0;
2493         struct btrfs_path *path;
2494         struct extent_buffer *leaf;
2495         unsigned long ptr;
2496
2497         path = btrfs_alloc_path();
2498         BUG_ON(!path);
2499         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2500         if (!ret) {
2501                 leaf = path->nodes[0];
2502                 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2503                 write_extent_buffer(leaf, data, ptr, data_size);
2504                 btrfs_mark_buffer_dirty(leaf);
2505         }
2506         btrfs_free_path(path);
2507         return ret;
2508 }
2509
2510 /*
2511  * delete the pointer from a given node.
2512  *
2513  * If the delete empties a node, the node is removed from the tree,
2514  * continuing all the way the root if required.  The root is converted into
2515  * a leaf if all the nodes are emptied.
2516  */
2517 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2518                    struct btrfs_path *path, int level, int slot)
2519 {
2520         struct extent_buffer *parent = path->nodes[level];
2521         u32 nritems;
2522         int ret = 0;
2523         int wret;
2524
2525         nritems = btrfs_header_nritems(parent);
2526         if (slot != nritems -1) {
2527                 memmove_extent_buffer(parent,
2528                               btrfs_node_key_ptr_offset(slot),
2529                               btrfs_node_key_ptr_offset(slot + 1),
2530                               sizeof(struct btrfs_key_ptr) *
2531                               (nritems - slot - 1));
2532         }
2533         nritems--;
2534         btrfs_set_header_nritems(parent, nritems);
2535         if (nritems == 0 && parent == root->node) {
2536                 BUG_ON(btrfs_header_level(root->node) != 1);
2537                 /* just turn the root into a leaf and break */
2538                 btrfs_set_header_level(root->node, 0);
2539         } else if (slot == 0) {
2540                 struct btrfs_disk_key disk_key;
2541
2542                 btrfs_node_key(parent, &disk_key, 0);
2543                 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2544                 if (wret)
2545                         ret = wret;
2546         }
2547         btrfs_mark_buffer_dirty(parent);
2548         return ret;
2549 }
2550
2551 /*
2552  * delete the item at the leaf level in path.  If that empties
2553  * the leaf, remove it from the tree
2554  */
2555 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2556                     struct btrfs_path *path, int slot, int nr)
2557 {
2558         struct extent_buffer *leaf;
2559         struct btrfs_item *item;
2560         int last_off;
2561         int dsize = 0;
2562         int ret = 0;
2563         int wret;
2564         int i;
2565         u32 nritems;
2566
2567         leaf = path->nodes[0];
2568         last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2569
2570         for (i = 0; i < nr; i++)
2571                 dsize += btrfs_item_size_nr(leaf, slot + i);
2572
2573         nritems = btrfs_header_nritems(leaf);
2574
2575         if (slot + nr != nritems) {
2576                 int i;
2577                 int data_end = leaf_data_end(root, leaf);
2578
2579                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2580                               data_end + dsize,
2581                               btrfs_leaf_data(leaf) + data_end,
2582                               last_off - data_end);
2583
2584                 for (i = slot + nr; i < nritems; i++) {
2585                         u32 ioff;
2586
2587                         item = btrfs_item_nr(leaf, i);
2588                         if (!leaf->map_token) {
2589                                 map_extent_buffer(leaf, (unsigned long)item,
2590                                         sizeof(struct btrfs_item),
2591                                         &leaf->map_token, &leaf->kaddr,
2592                                         &leaf->map_start, &leaf->map_len,
2593                                         KM_USER1);
2594                         }
2595                         ioff = btrfs_item_offset(leaf, item);
2596                         btrfs_set_item_offset(leaf, item, ioff + dsize);
2597                 }
2598
2599                 if (leaf->map_token) {
2600                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2601                         leaf->map_token = NULL;
2602                 }
2603
2604                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2605                               btrfs_item_nr_offset(slot + nr),
2606                               sizeof(struct btrfs_item) *
2607                               (nritems - slot - nr));
2608         }
2609         btrfs_set_header_nritems(leaf, nritems - nr);
2610         nritems -= nr;
2611
2612         /* delete the leaf if we've emptied it */
2613         if (nritems == 0) {
2614                 if (leaf == root->node) {
2615                         btrfs_set_header_level(leaf, 0);
2616                 } else {
2617                         u64 root_gen = btrfs_header_generation(path->nodes[1]);
2618                         clean_tree_block(trans, root, leaf);
2619                         wait_on_tree_block_writeback(root, leaf);
2620                         wret = del_ptr(trans, root, path, 1, path->slots[1]);
2621                         if (wret)
2622                                 ret = wret;
2623                         wret = btrfs_free_extent(trans, root,
2624                                          leaf->start, leaf->len,
2625                                          btrfs_header_owner(path->nodes[1]),
2626                                          root_gen, 0, 0, 1);
2627                         if (wret)
2628                                 ret = wret;
2629                 }
2630         } else {
2631                 int used = leaf_space_used(leaf, 0, nritems);
2632                 if (slot == 0) {
2633                         struct btrfs_disk_key disk_key;
2634
2635                         btrfs_item_key(leaf, &disk_key, 0);
2636                         wret = fixup_low_keys(trans, root, path,
2637                                               &disk_key, 1);
2638                         if (wret)
2639                                 ret = wret;
2640                 }
2641
2642                 /* delete the leaf if it is mostly empty */
2643                 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2644                         /* push_leaf_left fixes the path.
2645                          * make sure the path still points to our leaf
2646                          * for possible call to del_ptr below
2647                          */
2648                         slot = path->slots[1];
2649                         extent_buffer_get(leaf);
2650
2651                         wret = push_leaf_left(trans, root, path, 1, 1);
2652                         if (wret < 0 && wret != -ENOSPC)
2653                                 ret = wret;
2654
2655                         if (path->nodes[0] == leaf &&
2656                             btrfs_header_nritems(leaf)) {
2657                                 wret = push_leaf_right(trans, root, path, 1, 1);
2658                                 if (wret < 0 && wret != -ENOSPC)
2659                                         ret = wret;
2660                         }
2661
2662                         if (btrfs_header_nritems(leaf) == 0) {
2663                                 u64 root_gen;
2664                                 u64 bytenr = leaf->start;
2665                                 u32 blocksize = leaf->len;
2666
2667                                 root_gen = btrfs_header_generation(
2668                                                            path->nodes[1]);
2669
2670                                 clean_tree_block(trans, root, leaf);
2671                                 wait_on_tree_block_writeback(root, leaf);
2672
2673                                 wret = del_ptr(trans, root, path, 1, slot);
2674                                 if (wret)
2675                                         ret = wret;
2676
2677                                 free_extent_buffer(leaf);
2678                                 wret = btrfs_free_extent(trans, root, bytenr,
2679                                              blocksize,
2680                                              btrfs_header_owner(path->nodes[1]),
2681                                              root_gen, 0, 0, 1);
2682                                 if (wret)
2683                                         ret = wret;
2684                         } else {
2685                                 btrfs_mark_buffer_dirty(leaf);
2686                                 free_extent_buffer(leaf);
2687                         }
2688                 } else {
2689                         btrfs_mark_buffer_dirty(leaf);
2690                 }
2691         }
2692         return ret;
2693 }
2694
2695 /*
2696  * walk up the tree as far as required to find the previous leaf.
2697  * returns 0 if it found something or 1 if there are no lesser leaves.
2698  * returns < 0 on io errors.
2699  */
2700 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2701 {
2702         u64 bytenr;
2703         int slot;
2704         int level = 1;
2705         struct extent_buffer *c;
2706         struct extent_buffer *next = NULL;
2707
2708         while(level < BTRFS_MAX_LEVEL) {
2709                 if (!path->nodes[level])
2710                         return 1;
2711
2712                 slot = path->slots[level];
2713                 c = path->nodes[level];
2714                 if (slot == 0) {
2715                         level++;
2716                         if (level == BTRFS_MAX_LEVEL)
2717                                 return 1;
2718                         continue;
2719                 }
2720                 slot--;
2721
2722                 bytenr = btrfs_node_blockptr(c, slot);
2723                 if (next)
2724                         free_extent_buffer(next);
2725
2726                 next = read_tree_block(root, bytenr,
2727                                        btrfs_level_size(root, level - 1));
2728                 break;
2729         }
2730         path->slots[level] = slot;
2731         while(1) {
2732                 level--;
2733                 c = path->nodes[level];
2734                 free_extent_buffer(c);
2735                 slot = btrfs_header_nritems(next);
2736                 if (slot != 0)
2737                         slot--;
2738                 path->nodes[level] = next;
2739                 path->slots[level] = slot;
2740                 if (!level)
2741                         break;
2742                 next = read_tree_block(root, btrfs_node_blockptr(next, slot),
2743                                        btrfs_level_size(root, level - 1));
2744         }
2745         return 0;
2746 }
2747
2748 /*
2749  * walk up the tree as far as required to find the next leaf.
2750  * returns 0 if it found something or 1 if there are no greater leaves.
2751  * returns < 0 on io errors.
2752  */
2753 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2754 {
2755         int slot;
2756         int level = 1;
2757         u64 bytenr;
2758         struct extent_buffer *c;
2759         struct extent_buffer *next = NULL;
2760
2761         while(level < BTRFS_MAX_LEVEL) {
2762                 if (!path->nodes[level])
2763                         return 1;
2764
2765                 slot = path->slots[level] + 1;
2766                 c = path->nodes[level];
2767                 if (slot >= btrfs_header_nritems(c)) {
2768                         level++;
2769                         if (level == BTRFS_MAX_LEVEL)
2770                                 return 1;
2771                         continue;
2772                 }
2773
2774                 bytenr = btrfs_node_blockptr(c, slot);
2775                 if (next)
2776                         free_extent_buffer(next);
2777
2778                 if (path->reada)
2779                         reada_for_search(root, path, level, slot, 0);
2780
2781                 next = read_tree_block(root, bytenr,
2782                                        btrfs_level_size(root, level -1));
2783                 break;
2784         }
2785         path->slots[level] = slot;
2786         while(1) {
2787                 level--;
2788                 c = path->nodes[level];
2789                 free_extent_buffer(c);
2790                 path->nodes[level] = next;
2791                 path->slots[level] = 0;
2792                 if (!level)
2793                         break;
2794                 if (path->reada)
2795                         reada_for_search(root, path, level, 0, 0);
2796                 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2797                                        btrfs_level_size(root, level - 1));
2798         }
2799         return 0;
2800 }
2801
2802 int btrfs_previous_item(struct btrfs_root *root,
2803                         struct btrfs_path *path, u64 min_objectid,
2804                         int type)
2805 {
2806         struct btrfs_key found_key;
2807         struct extent_buffer *leaf;
2808         int ret;
2809
2810         while(1) {
2811                 if (path->slots[0] == 0) {
2812                         ret = btrfs_prev_leaf(root, path);
2813                         if (ret != 0)
2814                                 return ret;
2815                 } else {
2816                         path->slots[0]--;
2817                 }
2818                 leaf = path->nodes[0];
2819                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2820                 if (found_key.type == type)
2821                         return 0;
2822         }
2823         return 1;
2824 }
2825