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 #include "locking.h"
  25
  26 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
  27                       *root, struct btrfs_path *path, int level);
  28 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
  29                       *root, struct btrfs_key *ins_key,
  30                       struct btrfs_path *path, int data_size, int extend);
  31 static int push_node_left(struct btrfs_trans_handle *trans,
  32                           struct btrfs_root *root, struct extent_buffer *dst,
  33                           struct extent_buffer *src, int empty);
  34 static int balance_node_right(struct btrfs_trans_handle *trans,
  35                               struct btrfs_root *root,
  36                               struct extent_buffer *dst_buf,
  37                               struct extent_buffer *src_buf);
  38 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  39                    struct btrfs_path *path, int level, int slot);
  40
  41 inline void btrfs_init_path(struct btrfs_path *p)
  42 {
  43         memset(p, 0, sizeof(*p));
  44 }
  45
  46 struct btrfs_path *btrfs_alloc_path(void)
  47 {
  48         struct btrfs_path *path;
  49         path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
  50         if (path) {
  51                 btrfs_init_path(path);
  52                 path->reada = 1;
  53         }
  54         return path;
  55 }
  56
  57 void btrfs_free_path(struct btrfs_path *p)
  58 {
  59         btrfs_release_path(NULL, p);
  60         kmem_cache_free(btrfs_path_cachep, p);
  61 }
  62
  63 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
  64 {
  65         int i;
  66         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
  67                 if (!p->nodes[i])
  68                         continue;
  69                 if (p->locks[i]) {
  70                         btrfs_tree_unlock(p->nodes[i]);
  71                         p->locks[i] = 0;
  72                 }
  73                 free_extent_buffer(p->nodes[i]);
  74         }
  75         memset(p, 0, sizeof(*p));
  76 }
  77
  78 struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
  79 {
  80         struct extent_buffer *eb;
  81         spin_lock(&root->node_lock);
  82         eb = root->node;
  83         extent_buffer_get(eb);
  84         spin_unlock(&root->node_lock);
  85         return eb;
  86 }
  87
  88 struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
  89 {
  90         struct extent_buffer *eb;
  91
  92         while(1) {
  93                 eb = btrfs_root_node(root);
  94                 btrfs_tree_lock(eb);
  95
  96                 spin_lock(&root->node_lock);
  97                 if (eb == root->node) {
  98                         spin_unlock(&root->node_lock);
  99                         break;
 100                 }
 101                 spin_unlock(&root->node_lock);
 102
 103                 btrfs_tree_unlock(eb);
 104                 free_extent_buffer(eb);
 105         }
 106         return eb;
 107 }
 108
 109 static void add_root_to_dirty_list(struct btrfs_root *root)
 110 {
 111         if (root->track_dirty && list_empty(&root->dirty_list)) {
 112                 list_add(&root->dirty_list,
 113                          &root->fs_info->dirty_cowonly_roots);
 114         }
 115 }
 116
 117 int btrfs_copy_root(struct btrfs_trans_handle *trans,
 118                       struct btrfs_root *root,
 119                       struct extent_buffer *buf,
 120                       struct extent_buffer **cow_ret, u64 new_root_objectid)
 121 {
 122         struct extent_buffer *cow;
 123         u32 nritems;
 124         int ret = 0;
 125         int level;
 126         struct btrfs_key first_key;
 127         struct btrfs_root *new_root;
 128
 129         new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
 130         if (!new_root)
 131                 return -ENOMEM;
 132
 133         memcpy(new_root, root, sizeof(*new_root));
 134         new_root->root_key.objectid = new_root_objectid;
 135
 136         WARN_ON(root->ref_cows && trans->transid !=
 137                 root->fs_info->running_transaction->transid);
 138         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 139
 140         level = btrfs_header_level(buf);
 141         nritems = btrfs_header_nritems(buf);
 142         if (nritems) {
 143                 if (level == 0)
 144                         btrfs_item_key_to_cpu(buf, &first_key, 0);
 145                 else
 146                         btrfs_node_key_to_cpu(buf, &first_key, 0);
 147         } else {
 148                 first_key.objectid = 0;
 149         }
 150         cow = btrfs_alloc_free_block(trans, new_root, buf->len,
 151                                        new_root_objectid,
 152                                        trans->transid, first_key.objectid,
 153                                        level, buf->start, 0);
 154         if (IS_ERR(cow)) {
 155                 kfree(new_root);
 156                 return PTR_ERR(cow);
 157         }
 158
 159         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 160         btrfs_set_header_bytenr(cow, cow->start);
 161         btrfs_set_header_generation(cow, trans->transid);
 162         btrfs_set_header_owner(cow, new_root_objectid);
 163         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 164
 165         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 166         ret = btrfs_inc_ref(trans, new_root, buf);
 167         kfree(new_root);
 168
 169         if (ret)
 170                 return ret;
 171
 172         btrfs_mark_buffer_dirty(cow);
 173         *cow_ret = cow;
 174         return 0;
 175 }
 176
 177 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 178                              struct btrfs_root *root,
 179                              struct extent_buffer *buf,
 180                              struct extent_buffer *parent, int parent_slot,
 181                              struct extent_buffer **cow_ret,
 182                              u64 search_start, u64 empty_size)
 183 {
 184         u64 root_gen;
 185         struct extent_buffer *cow;
 186         u32 nritems;
 187         int ret = 0;
 188         int different_trans = 0;
 189         int level;
 190         int unlock_orig = 0;
 191         struct btrfs_key first_key;
 192
 193         if (*cow_ret == buf)
 194                 unlock_orig = 1;
 195
 196         WARN_ON(!btrfs_tree_locked(buf));
 197
 198         if (root->ref_cows) {
 199                 root_gen = trans->transid;
 200         } else {
 201                 root_gen = 0;
 202         }
 203         WARN_ON(root->ref_cows && trans->transid !=
 204                 root->fs_info->running_transaction->transid);
 205         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 206
 207         level = btrfs_header_level(buf);
 208         nritems = btrfs_header_nritems(buf);
 209         if (nritems) {
 210                 if (level == 0)
 211                         btrfs_item_key_to_cpu(buf, &first_key, 0);
 212                 else
 213                         btrfs_node_key_to_cpu(buf, &first_key, 0);
 214         } else {
 215                 first_key.objectid = 0;
 216         }
 217         cow = btrfs_alloc_free_block(trans, root, buf->len,
 218                                      root->root_key.objectid,
 219                                      root_gen, first_key.objectid, level,
 220                                      search_start, empty_size);
 221         if (IS_ERR(cow))
 222                 return PTR_ERR(cow);
 223
 224         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 225         btrfs_set_header_bytenr(cow, cow->start);
 226         btrfs_set_header_generation(cow, trans->transid);
 227         btrfs_set_header_owner(cow, root->root_key.objectid);
 228         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 229
 230         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 231         if (btrfs_header_generation(buf) != trans->transid) {
 232                 different_trans = 1;
 233                 ret = btrfs_inc_ref(trans, root, buf);
 234                 if (ret)
 235                         return ret;
 236         } else {
 237                 clean_tree_block(trans, root, buf);
 238         }
 239
 240         if (buf == root->node) {
 241                 WARN_ON(parent && parent != buf);
 242                 root_gen = btrfs_header_generation(buf);
 243
 244                 spin_lock(&root->node_lock);
 245                 root->node = cow;
 246                 extent_buffer_get(cow);
 247                 spin_unlock(&root->node_lock);
 248
 249                 if (buf != root->commit_root) {
 250                         btrfs_free_extent(trans, root, buf->start,
 251                                           buf->len, root->root_key.objectid,
 252                                           root_gen, 0, 0, 1);
 253                 }
 254                 free_extent_buffer(buf);
 255                 add_root_to_dirty_list(root);
 256         } else {
 257                 root_gen = btrfs_header_generation(parent);
 258                 btrfs_set_node_blockptr(parent, parent_slot,
 259                                         cow->start);
 260                 WARN_ON(trans->transid == 0);
 261                 btrfs_set_node_ptr_generation(parent, parent_slot,
 262                                               trans->transid);
 263                 btrfs_mark_buffer_dirty(parent);
 264                 WARN_ON(btrfs_header_generation(parent) != trans->transid);
 265                 btrfs_free_extent(trans, root, buf->start, buf->len,
 266                                   btrfs_header_owner(parent), root_gen,
 267                                   0, 0, 1);
 268         }
 269         if (unlock_orig)
 270                 btrfs_tree_unlock(buf);
 271         free_extent_buffer(buf);
 272         btrfs_mark_buffer_dirty(cow);
 273         *cow_ret = cow;
 274         return 0;
 275 }
 276
 277 int btrfs_cow_block(struct btrfs_trans_handle *trans,
 278                     struct btrfs_root *root, struct extent_buffer *buf,
 279                     struct extent_buffer *parent, int parent_slot,
 280                     struct extent_buffer **cow_ret)
 281 {
 282         u64 search_start;
 283         u64 header_trans;
 284         int ret;
 285
 286         if (trans->transaction != root->fs_info->running_transaction) {
 287                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 288                        root->fs_info->running_transaction->transid);
 289                 WARN_ON(1);
 290         }
 291         if (trans->transid != root->fs_info->generation) {
 292                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 293                        root->fs_info->generation);
 294                 WARN_ON(1);
 295         }
 296
 297         header_trans = btrfs_header_generation(buf);
 298         spin_lock(&root->fs_info->hash_lock);
 299         if (header_trans == trans->transid &&
 300             !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
 301                 *cow_ret = buf;
 302                 spin_unlock(&root->fs_info->hash_lock);
 303                 return 0;
 304         }
 305         spin_unlock(&root->fs_info->hash_lock);
 306         search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
 307         ret = __btrfs_cow_block(trans, root, buf, parent,
 308                                  parent_slot, cow_ret, search_start, 0);
 309         return ret;
 310 }
 311
 312 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
 313 {
 314         if (blocknr < other && other - (blocknr + blocksize) < 32768)
 315                 return 1;
 316         if (blocknr > other && blocknr - (other + blocksize) < 32768)
 317                 return 1;
 318         return 0;
 319 }
 320
 321 /*
 322  * compare two keys in a memcmp fashion
 323  */
 324 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
 325 {
 326         struct btrfs_key k1;
 327
 328         btrfs_disk_key_to_cpu(&k1, disk);
 329
 330         if (k1.objectid > k2->objectid)
 331                 return 1;
 332         if (k1.objectid < k2->objectid)
 333                 return -1;
 334         if (k1.type > k2->type)
 335                 return 1;
 336         if (k1.type < k2->type)
 337                 return -1;
 338         if (k1.offset > k2->offset)
 339                 return 1;
 340         if (k1.offset < k2->offset)
 341                 return -1;
 342         return 0;
 343 }
 344
 345
 346 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 347                        struct btrfs_root *root, struct extent_buffer *parent,
 348                        int start_slot, int cache_only, u64 *last_ret,
 349                        struct btrfs_key *progress)
 350 {
 351         struct extent_buffer *cur;
 352         struct extent_buffer *tmp;
 353         u64 blocknr;
 354         u64 gen;
 355         u64 search_start = *last_ret;
 356         u64 last_block = 0;
 357         u64 other;
 358         u32 parent_nritems;
 359         int end_slot;
 360         int i;
 361         int err = 0;
 362         int parent_level;
 363         int uptodate;
 364         u32 blocksize;
 365         int progress_passed = 0;
 366         struct btrfs_disk_key disk_key;
 367
 368         /* FIXME this code needs locking */
 369         return 0;
 370
 371         parent_level = btrfs_header_level(parent);
 372         if (cache_only && parent_level != 1)
 373                 return 0;
 374
 375         if (trans->transaction != root->fs_info->running_transaction) {
 376                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 377                        root->fs_info->running_transaction->transid);
 378                 WARN_ON(1);
 379         }
 380         if (trans->transid != root->fs_info->generation) {
 381                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 382                        root->fs_info->generation);
 383                 WARN_ON(1);
 384         }
 385
 386         parent_nritems = btrfs_header_nritems(parent);
 387         blocksize = btrfs_level_size(root, parent_level - 1);
 388         end_slot = parent_nritems;
 389
 390         if (parent_nritems == 1)
 391                 return 0;
 392
 393         for (i = start_slot; i < end_slot; i++) {
 394                 int close = 1;
 395
 396                 if (!parent->map_token) {
 397                         map_extent_buffer(parent,
 398                                         btrfs_node_key_ptr_offset(i),
 399                                         sizeof(struct btrfs_key_ptr),
 400                                         &parent->map_token, &parent->kaddr,
 401                                         &parent->map_start, &parent->map_len,
 402                                         KM_USER1);
 403                 }
 404                 btrfs_node_key(parent, &disk_key, i);
 405                 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
 406                         continue;
 407
 408                 progress_passed = 1;
 409                 blocknr = btrfs_node_blockptr(parent, i);
 410                 gen = btrfs_node_ptr_generation(parent, i);
 411                 if (last_block == 0)
 412                         last_block = blocknr;
 413
 414                 if (i > 0) {
 415                         other = btrfs_node_blockptr(parent, i - 1);
 416                         close = close_blocks(blocknr, other, blocksize);
 417                 }
 418                 if (!close && i < end_slot - 2) {
 419                         other = btrfs_node_blockptr(parent, i + 1);
 420                         close = close_blocks(blocknr, other, blocksize);
 421                 }
 422                 if (close) {
 423                         last_block = blocknr;
 424                         continue;
 425                 }
 426                 if (parent->map_token) {
 427                         unmap_extent_buffer(parent, parent->map_token,
 428                                             KM_USER1);
 429                         parent->map_token = NULL;
 430                 }
 431
 432                 cur = btrfs_find_tree_block(root, blocknr, blocksize);
 433                 if (cur)
 434                         uptodate = btrfs_buffer_uptodate(cur, gen);
 435                 else
 436                         uptodate = 0;
 437                 if (!cur || !uptodate) {
 438                         if (cache_only) {
 439                                 free_extent_buffer(cur);
 440                                 continue;
 441                         }
 442                         if (!cur) {
 443                                 cur = read_tree_block(root, blocknr,
 444                                                          blocksize, gen);
 445                         } else if (!uptodate) {
 446                                 btrfs_read_buffer(cur, gen);
 447                         }
 448                 }
 449                 if (search_start == 0)
 450                         search_start = last_block;
 451
 452                 err = __btrfs_cow_block(trans, root, cur, parent, i,
 453                                         &tmp, search_start,
 454                                         min(16 * blocksize,
 455                                             (end_slot - i) * blocksize));
 456                 if (err) {
 457                         free_extent_buffer(cur);
 458                         break;
 459                 }
 460                 search_start = tmp->start;
 461                 last_block = tmp->start;
 462                 *last_ret = search_start;
 463                 if (parent_level == 1)
 464                         btrfs_clear_buffer_defrag(tmp);
 465                 free_extent_buffer(tmp);
 466         }
 467         if (parent->map_token) {
 468                 unmap_extent_buffer(parent, parent->map_token,
 469                                     KM_USER1);
 470                 parent->map_token = NULL;
 471         }
 472         return err;
 473 }
 474
 475 /*
 476  * The leaf data grows from end-to-front in the node.
 477  * this returns the address of the start of the last item,
 478  * which is the stop of the leaf data stack
 479  */
 480 static inline unsigned int leaf_data_end(struct btrfs_root *root,
 481                                          struct extent_buffer *leaf)
 482 {
 483         u32 nr = btrfs_header_nritems(leaf);
 484         if (nr == 0)
 485                 return BTRFS_LEAF_DATA_SIZE(root);
 486         return btrfs_item_offset_nr(leaf, nr - 1);
 487 }
 488
 489 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
 490                       int level)
 491 {
 492         struct extent_buffer *parent = NULL;
 493         struct extent_buffer *node = path->nodes[level];
 494         struct btrfs_disk_key parent_key;
 495         struct btrfs_disk_key node_key;
 496         int parent_slot;
 497         int slot;
 498         struct btrfs_key cpukey;
 499         u32 nritems = btrfs_header_nritems(node);
 500
 501         if (path->nodes[level + 1])
 502                 parent = path->nodes[level + 1];
 503
 504         slot = path->slots[level];
 505         BUG_ON(nritems == 0);
 506         if (parent) {
 507                 parent_slot = path->slots[level + 1];
 508                 btrfs_node_key(parent, &parent_key, parent_slot);
 509                 btrfs_node_key(node, &node_key, 0);
 510                 BUG_ON(memcmp(&parent_key, &node_key,
 511                               sizeof(struct btrfs_disk_key)));
 512                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 513                        btrfs_header_bytenr(node));
 514         }
 515         BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
 516         if (slot != 0) {
 517                 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
 518                 btrfs_node_key(node, &node_key, slot);
 519                 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
 520         }
 521         if (slot < nritems - 1) {
 522                 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
 523                 btrfs_node_key(node, &node_key, slot);
 524                 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
 525         }
 526         return 0;
 527 }
 528
 529 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
 530                       int level)
 531 {
 532         struct extent_buffer *leaf = path->nodes[level];
 533         struct extent_buffer *parent = NULL;
 534         int parent_slot;
 535         struct btrfs_key cpukey;
 536         struct btrfs_disk_key parent_key;
 537         struct btrfs_disk_key leaf_key;
 538         int slot = path->slots[0];
 539
 540         u32 nritems = btrfs_header_nritems(leaf);
 541
 542         if (path->nodes[level + 1])
 543                 parent = path->nodes[level + 1];
 544
 545         if (nritems == 0)
 546                 return 0;
 547
 548         if (parent) {
 549                 parent_slot = path->slots[level + 1];
 550                 btrfs_node_key(parent, &parent_key, parent_slot);
 551                 btrfs_item_key(leaf, &leaf_key, 0);
 552
 553                 BUG_ON(memcmp(&parent_key, &leaf_key,
 554                        sizeof(struct btrfs_disk_key)));
 555                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 556                        btrfs_header_bytenr(leaf));
 557         }
 558 #if 0
 559         for (i = 0; nritems > 1 && i < nritems - 2; i++) {
 560                 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
 561                 btrfs_item_key(leaf, &leaf_key, i);
 562                 if (comp_keys(&leaf_key, &cpukey) >= 0) {
 563                         btrfs_print_leaf(root, leaf);
 564                         printk("slot %d offset bad key\n", i);
 565                         BUG_ON(1);
 566                 }
 567                 if (btrfs_item_offset_nr(leaf, i) !=
 568                         btrfs_item_end_nr(leaf, i + 1)) {
 569                         btrfs_print_leaf(root, leaf);
 570                         printk("slot %d offset bad\n", i);
 571                         BUG_ON(1);
 572                 }
 573                 if (i == 0) {
 574                         if (btrfs_item_offset_nr(leaf, i) +
 575                                btrfs_item_size_nr(leaf, i) !=
 576                                BTRFS_LEAF_DATA_SIZE(root)) {
 577                                 btrfs_print_leaf(root, leaf);
 578                                 printk("slot %d first offset bad\n", i);
 579                                 BUG_ON(1);
 580                         }
 581                 }
 582         }
 583         if (nritems > 0) {
 584                 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
 585                                 btrfs_print_leaf(root, leaf);
 586                                 printk("slot %d bad size \n", nritems - 1);
 587                                 BUG_ON(1);
 588                 }
 589         }
 590 #endif
 591         if (slot != 0 && slot < nritems - 1) {
 592                 btrfs_item_key(leaf, &leaf_key, slot);
 593                 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
 594                 if (comp_keys(&leaf_key, &cpukey) <= 0) {
 595                         btrfs_print_leaf(root, leaf);
 596                         printk("slot %d offset bad key\n", slot);
 597                         BUG_ON(1);
 598                 }
 599                 if (btrfs_item_offset_nr(leaf, slot - 1) !=
 600                        btrfs_item_end_nr(leaf, slot)) {
 601                         btrfs_print_leaf(root, leaf);
 602                         printk("slot %d offset bad\n", slot);
 603                         BUG_ON(1);
 604                 }
 605         }
 606         if (slot < nritems - 1) {
 607                 btrfs_item_key(leaf, &leaf_key, slot);
 608                 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
 609                 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
 610                 if (btrfs_item_offset_nr(leaf, slot) !=
 611                         btrfs_item_end_nr(leaf, slot + 1)) {
 612                         btrfs_print_leaf(root, leaf);
 613                         printk("slot %d offset bad\n", slot);
 614                         BUG_ON(1);
 615                 }
 616         }
 617         BUG_ON(btrfs_item_offset_nr(leaf, 0) +
 618                btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
 619         return 0;
 620 }
 621
 622 static int noinline check_block(struct btrfs_root *root,
 623                                 struct btrfs_path *path, int level)
 624 {
 625         u64 found_start;
 626         return 0;
 627         if (btrfs_header_level(path->nodes[level]) != level)
 628             printk("warning: bad level %Lu wanted %d found %d\n",
 629                    path->nodes[level]->start, level,
 630                    btrfs_header_level(path->nodes[level]));
 631         found_start = btrfs_header_bytenr(path->nodes[level]);
 632         if (found_start != path->nodes[level]->start) {
 633             printk("warning: bad bytentr %Lu found %Lu\n",
 634                    path->nodes[level]->start, found_start);
 635         }
 636 #if 0
 637         struct extent_buffer *buf = path->nodes[level];
 638
 639         if (memcmp_extent_buffer(buf, root->fs_info->fsid,
 640                                  (unsigned long)btrfs_header_fsid(buf),
 641                                  BTRFS_FSID_SIZE)) {
 642                 printk("warning bad block %Lu\n", buf->start);
 643                 return 1;
 644         }
 645 #endif
 646         if (level == 0)
 647                 return check_leaf(root, path, level);
 648         return check_node(root, path, level);
 649 }
 650
 651 /*
 652  * search for key in the extent_buffer.  The items start at offset p,
 653  * and they are item_size apart.  There are 'max' items in p.
 654  *
 655  * the slot in the array is returned via slot, and it points to
 656  * the place where you would insert key if it is not found in
 657  * the array.
 658  *
 659  * slot may point to max if the key is bigger than all of the keys
 660  */
 661 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
 662                               int item_size, struct btrfs_key *key,
 663                               int max, int *slot)
 664 {
 665         int low = 0;
 666         int high = max;
 667         int mid;
 668         int ret;
 669         struct btrfs_disk_key *tmp = NULL;
 670         struct btrfs_disk_key unaligned;
 671         unsigned long offset;
 672         char *map_token = NULL;
 673         char *kaddr = NULL;
 674         unsigned long map_start = 0;
 675         unsigned long map_len = 0;
 676         int err;
 677
 678         while(low < high) {
 679                 mid = (low + high) / 2;
 680                 offset = p + mid * item_size;
 681
 682                 if (!map_token || offset < map_start ||
 683                     (offset + sizeof(struct btrfs_disk_key)) >
 684                     map_start + map_len) {
 685                         if (map_token) {
 686                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 687                                 map_token = NULL;
 688                         }
 689                         err = map_extent_buffer(eb, offset,
 690                                                 sizeof(struct btrfs_disk_key),
 691                                                 &map_token, &kaddr,
 692                                                 &map_start, &map_len, KM_USER0);
 693
 694                         if (!err) {
 695                                 tmp = (struct btrfs_disk_key *)(kaddr + offset -
 696                                                         map_start);
 697                         } else {
 698                                 read_extent_buffer(eb, &unaligned,
 699                                                    offset, sizeof(unaligned));
 700                                 tmp = &unaligned;
 701                         }
 702
 703                 } else {
 704                         tmp = (struct btrfs_disk_key *)(kaddr + offset -
 705                                                         map_start);
 706                 }
 707                 ret = comp_keys(tmp, key);
 708
 709                 if (ret < 0)
 710                         low = mid + 1;
 711                 else if (ret > 0)
 712                         high = mid;
 713                 else {
 714                         *slot = mid;
 715                         if (map_token)
 716                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 717                         return 0;
 718                 }
 719         }
 720         *slot = low;
 721         if (map_token)
 722                 unmap_extent_buffer(eb, map_token, KM_USER0);
 723         return 1;
 724 }
 725
 726 /*
 727  * simple bin_search frontend that does the right thing for
 728  * leaves vs nodes
 729  */
 730 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
 731                       int level, int *slot)
 732 {
 733         if (level == 0) {
 734                 return generic_bin_search(eb,
 735                                           offsetof(struct btrfs_leaf, items),
 736                                           sizeof(struct btrfs_item),
 737                                           key, btrfs_header_nritems(eb),
 738                                           slot);
 739         } else {
 740                 return generic_bin_search(eb,
 741                                           offsetof(struct btrfs_node, ptrs),
 742                                           sizeof(struct btrfs_key_ptr),
 743                                           key, btrfs_header_nritems(eb),
 744                                           slot);
 745         }
 746         return -1;
 747 }
 748
 749 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
 750                                    struct extent_buffer *parent, int slot)
 751 {
 752         int level = btrfs_header_level(parent);
 753         if (slot < 0)
 754                 return NULL;
 755         if (slot >= btrfs_header_nritems(parent))
 756                 return NULL;
 757
 758         BUG_ON(level == 0);
 759
 760         return read_tree_block(root, btrfs_node_blockptr(parent, slot),
 761                        btrfs_level_size(root, level - 1),
 762                        btrfs_node_ptr_generation(parent, slot));
 763 }
 764
 765 static int balance_level(struct btrfs_trans_handle *trans,
 766                          struct btrfs_root *root,
 767                          struct btrfs_path *path, int level)
 768 {
 769         struct extent_buffer *right = NULL;
 770         struct extent_buffer *mid;
 771         struct extent_buffer *left = NULL;
 772         struct extent_buffer *parent = NULL;
 773         int ret = 0;
 774         int wret;
 775         int pslot;
 776         int orig_slot = path->slots[level];
 777         int err_on_enospc = 0;
 778         u64 orig_ptr;
 779
 780         if (level == 0)
 781                 return 0;
 782
 783         mid = path->nodes[level];
 784         WARN_ON(!path->locks[level]);
 785         WARN_ON(btrfs_header_generation(mid) != trans->transid);
 786
 787         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 788
 789         if (level < BTRFS_MAX_LEVEL - 1)
 790                 parent = path->nodes[level + 1];
 791         pslot = path->slots[level + 1];
 792
 793         /*
 794          * deal with the case where there is only one pointer in the root
 795          * by promoting the node below to a root
 796          */
 797         if (!parent) {
 798                 struct extent_buffer *child;
 799
 800                 if (btrfs_header_nritems(mid) != 1)
 801                         return 0;
 802
 803                 /* promote the child to a root */
 804                 child = read_node_slot(root, mid, 0);
 805                 btrfs_tree_lock(child);
 806                 BUG_ON(!child);
 807                 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
 808                 BUG_ON(ret);
 809
 810                 spin_lock(&root->node_lock);
 811                 root->node = child;
 812                 spin_unlock(&root->node_lock);
 813
 814                 add_root_to_dirty_list(root);
 815                 btrfs_tree_unlock(child);
 816                 path->locks[level] = 0;
 817                 path->nodes[level] = NULL;
 818                 clean_tree_block(trans, root, mid);
 819                 btrfs_tree_unlock(mid);
 820                 /* once for the path */
 821                 free_extent_buffer(mid);
 822                 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
 823                                         root->root_key.objectid,
 824                                         btrfs_header_generation(mid), 0, 0, 1);
 825                 /* once for the root ptr */
 826                 free_extent_buffer(mid);
 827                 return ret;
 828         }
 829         if (btrfs_header_nritems(mid) >
 830             BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
 831                 return 0;
 832
 833         if (btrfs_header_nritems(mid) < 2)
 834                 err_on_enospc = 1;
 835
 836         left = read_node_slot(root, parent, pslot - 1);
 837         if (left) {
 838                 btrfs_tree_lock(left);
 839                 wret = btrfs_cow_block(trans, root, left,
 840                                        parent, pslot - 1, &left);
 841                 if (wret) {
 842                         ret = wret;
 843                         goto enospc;
 844                 }
 845         }
 846         right = read_node_slot(root, parent, pslot + 1);
 847         if (right) {
 848                 btrfs_tree_lock(right);
 849                 wret = btrfs_cow_block(trans, root, right,
 850                                        parent, pslot + 1, &right);
 851                 if (wret) {
 852                         ret = wret;
 853                         goto enospc;
 854                 }
 855         }
 856
 857         /* first, try to make some room in the middle buffer */
 858         if (left) {
 859                 orig_slot += btrfs_header_nritems(left);
 860                 wret = push_node_left(trans, root, left, mid, 1);
 861                 if (wret < 0)
 862                         ret = wret;
 863                 if (btrfs_header_nritems(mid) < 2)
 864                         err_on_enospc = 1;
 865         }
 866
 867         /*
 868          * then try to empty the right most buffer into the middle
 869          */
 870         if (right) {
 871                 wret = push_node_left(trans, root, mid, right, 1);
 872                 if (wret < 0 && wret != -ENOSPC)
 873                         ret = wret;
 874                 if (btrfs_header_nritems(right) == 0) {
 875                         u64 bytenr = right->start;
 876                         u64 generation = btrfs_header_generation(parent);
 877                         u32 blocksize = right->len;
 878
 879                         clean_tree_block(trans, root, right);
 880                         btrfs_tree_unlock(right);
 881                         free_extent_buffer(right);
 882                         right = NULL;
 883                         wret = del_ptr(trans, root, path, level + 1, pslot +
 884                                        1);
 885                         if (wret)
 886                                 ret = wret;
 887                         wret = btrfs_free_extent(trans, root, bytenr,
 888                                                  blocksize,
 889                                                  btrfs_header_owner(parent),
 890                                                  generation, 0, 0, 1);
 891                         if (wret)
 892                                 ret = wret;
 893                 } else {
 894                         struct btrfs_disk_key right_key;
 895                         btrfs_node_key(right, &right_key, 0);
 896                         btrfs_set_node_key(parent, &right_key, pslot + 1);
 897                         btrfs_mark_buffer_dirty(parent);
 898                 }
 899         }
 900         if (btrfs_header_nritems(mid) == 1) {
 901                 /*
 902                  * we're not allowed to leave a node with one item in the
 903                  * tree during a delete.  A deletion from lower in the tree
 904                  * could try to delete the only pointer in this node.
 905                  * So, pull some keys from the left.
 906                  * There has to be a left pointer at this point because
 907                  * otherwise we would have pulled some pointers from the
 908                  * right
 909                  */
 910                 BUG_ON(!left);
 911                 wret = balance_node_right(trans, root, mid, left);
 912                 if (wret < 0) {
 913                         ret = wret;
 914                         goto enospc;
 915                 }
 916                 if (wret == 1) {
 917                         wret = push_node_left(trans, root, left, mid, 1);
 918                         if (wret < 0)
 919                                 ret = wret;
 920                 }
 921                 BUG_ON(wret == 1);
 922         }
 923         if (btrfs_header_nritems(mid) == 0) {
 924                 /* we've managed to empty the middle node, drop it */
 925                 u64 root_gen = btrfs_header_generation(parent);
 926                 u64 bytenr = mid->start;
 927                 u32 blocksize = mid->len;
 928
 929                 clean_tree_block(trans, root, mid);
 930                 btrfs_tree_unlock(mid);
 931                 free_extent_buffer(mid);
 932                 mid = NULL;
 933                 wret = del_ptr(trans, root, path, level + 1, pslot);
 934                 if (wret)
 935                         ret = wret;
 936                 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
 937                                          btrfs_header_owner(parent),
 938                                          root_gen, 0, 0, 1);
 939                 if (wret)
 940                         ret = wret;
 941         } else {
 942                 /* update the parent key to reflect our changes */
 943                 struct btrfs_disk_key mid_key;
 944                 btrfs_node_key(mid, &mid_key, 0);
 945                 btrfs_set_node_key(parent, &mid_key, pslot);
 946                 btrfs_mark_buffer_dirty(parent);
 947         }
 948
 949         /* update the path */
 950         if (left) {
 951                 if (btrfs_header_nritems(left) > orig_slot) {
 952                         extent_buffer_get(left);
 953                         /* left was locked after cow */
 954                         path->nodes[level] = left;
 955                         path->slots[level + 1] -= 1;
 956                         path->slots[level] = orig_slot;
 957                         if (mid) {
 958                                 btrfs_tree_unlock(mid);
 959                                 free_extent_buffer(mid);
 960                         }
 961                 } else {
 962                         orig_slot -= btrfs_header_nritems(left);
 963                         path->slots[level] = orig_slot;
 964                 }
 965         }
 966         /* double check we haven't messed things up */
 967         check_block(root, path, level);
 968         if (orig_ptr !=
 969             btrfs_node_blockptr(path->nodes[level], path->slots[level]))
 970                 BUG();
 971 enospc:
 972         if (right) {
 973                 btrfs_tree_unlock(right);
 974                 free_extent_buffer(right);
 975         }
 976         if (left) {
 977                 if (path->nodes[level] != left)
 978                         btrfs_tree_unlock(left);
 979                 free_extent_buffer(left);
 980         }
 981         return ret;
 982 }
 983
 984 /* returns zero if the push worked, non-zero otherwise */
 985 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
 986                                           struct btrfs_root *root,
 987                                           struct btrfs_path *path, int level)
 988 {
 989         struct extent_buffer *right = NULL;
 990         struct extent_buffer *mid;
 991         struct extent_buffer *left = NULL;
 992         struct extent_buffer *parent = NULL;
 993         int ret = 0;
 994         int wret;
 995         int pslot;
 996         int orig_slot = path->slots[level];
 997         u64 orig_ptr;
 998
 999         if (level == 0)
1000                 return 1;
1001
1002         mid = path->nodes[level];
1003         WARN_ON(btrfs_header_generation(mid) != trans->transid);
1004         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
1005
1006         if (level < BTRFS_MAX_LEVEL - 1)
1007                 parent = path->nodes[level + 1];
1008         pslot = path->slots[level + 1];
1009
1010         if (!parent)
1011                 return 1;
1012
1013         left = read_node_slot(root, parent, pslot - 1);
1014
1015         /* first, try to make some room in the middle buffer */
1016         if (left) {
1017                 u32 left_nr;
1018
1019                 btrfs_tree_lock(left);
1020                 left_nr = btrfs_header_nritems(left);
1021                 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1022                         wret = 1;
1023                 } else {
1024                         ret = btrfs_cow_block(trans, root, left, parent,
1025                                               pslot - 1, &left);
1026                         if (ret)
1027                                 wret = 1;
1028                         else {
1029                                 wret = push_node_left(trans, root,
1030                                                       left, mid, 0);
1031                         }
1032                 }
1033                 if (wret < 0)
1034                         ret = wret;
1035                 if (wret == 0) {
1036                         struct btrfs_disk_key disk_key;
1037                         orig_slot += left_nr;
1038                         btrfs_node_key(mid, &disk_key, 0);
1039                         btrfs_set_node_key(parent, &disk_key, pslot);
1040                         btrfs_mark_buffer_dirty(parent);
1041                         if (btrfs_header_nritems(left) > orig_slot) {
1042                                 path->nodes[level] = left;
1043                                 path->slots[level + 1] -= 1;
1044                                 path->slots[level] = orig_slot;
1045                                 btrfs_tree_unlock(mid);
1046                                 free_extent_buffer(mid);
1047                         } else {
1048                                 orig_slot -=
1049                                         btrfs_header_nritems(left);
1050                                 path->slots[level] = orig_slot;
1051                                 btrfs_tree_unlock(left);
1052                                 free_extent_buffer(left);
1053                         }
1054                         return 0;
1055                 }
1056                 btrfs_tree_unlock(left);
1057                 free_extent_buffer(left);
1058         }
1059         right = read_node_slot(root, parent, pslot + 1);
1060
1061         /*
1062          * then try to empty the right most buffer into the middle
1063          */
1064         if (right) {
1065                 u32 right_nr;
1066                 btrfs_tree_lock(right);
1067                 right_nr = btrfs_header_nritems(right);
1068                 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1069                         wret = 1;
1070                 } else {
1071                         ret = btrfs_cow_block(trans, root, right,
1072                                               parent, pslot + 1,
1073                                               &right);
1074                         if (ret)
1075                                 wret = 1;
1076                         else {
1077                                 wret = balance_node_right(trans, root,
1078                                                           right, mid);
1079                         }
1080                 }
1081                 if (wret < 0)
1082                         ret = wret;
1083                 if (wret == 0) {
1084                         struct btrfs_disk_key disk_key;
1085
1086                         btrfs_node_key(right, &disk_key, 0);
1087                         btrfs_set_node_key(parent, &disk_key, pslot + 1);
1088                         btrfs_mark_buffer_dirty(parent);
1089
1090                         if (btrfs_header_nritems(mid) <= orig_slot) {
1091                                 path->nodes[level] = right;
1092                                 path->slots[level + 1] += 1;
1093                                 path->slots[level] = orig_slot -
1094                                         btrfs_header_nritems(mid);
1095                                 btrfs_tree_unlock(mid);
1096                                 free_extent_buffer(mid);
1097                         } else {
1098                                 btrfs_tree_unlock(right);
1099                                 free_extent_buffer(right);
1100                         }
1101                         return 0;
1102                 }
1103                 btrfs_tree_unlock(right);
1104                 free_extent_buffer(right);
1105         }
1106         return 1;
1107 }
1108
1109 /*
1110  * readahead one full node of leaves
1111  */
1112 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
1113                              int level, int slot, u64 objectid)
1114 {
1115         struct extent_buffer *node;
1116         struct btrfs_disk_key disk_key;
1117         u32 nritems;
1118         u64 search;
1119         u64 lowest_read;
1120         u64 highest_read;
1121         u64 nread = 0;
1122         int direction = path->reada;
1123         struct extent_buffer *eb;
1124         u32 nr;
1125         u32 blocksize;
1126         u32 nscan = 0;
1127
1128         if (level != 1)
1129                 return;
1130
1131         if (!path->nodes[level])
1132                 return;
1133
1134         node = path->nodes[level];
1135         WARN_ON(!path->skip_locking && !btrfs_tree_locked(node));
1136
1137         search = btrfs_node_blockptr(node, slot);
1138         blocksize = btrfs_level_size(root, level - 1);
1139         eb = btrfs_find_tree_block(root, search, blocksize);
1140         if (eb) {
1141                 free_extent_buffer(eb);
1142                 return;
1143         }
1144
1145         highest_read = search;
1146         lowest_read = search;
1147
1148         nritems = btrfs_header_nritems(node);
1149         nr = slot;
1150         while(1) {
1151                 if (direction < 0) {
1152                         if (nr == 0)
1153                                 break;
1154                         nr--;
1155                 } else if (direction > 0) {
1156                         nr++;
1157                         if (nr >= nritems)
1158                                 break;
1159                 }
1160                 if (path->reada < 0 && objectid) {
1161                         btrfs_node_key(node, &disk_key, nr);
1162                         if (btrfs_disk_key_objectid(&disk_key) != objectid)
1163                                 break;
1164                 }
1165                 search = btrfs_node_blockptr(node, nr);
1166                 if ((search >= lowest_read && search <= highest_read) ||
1167                     (search < lowest_read && lowest_read - search <= 32768) ||
1168                     (search > highest_read && search - highest_read <= 32768)) {
1169                         readahead_tree_block(root, search, blocksize,
1170                                      btrfs_node_ptr_generation(node, nr));
1171                         nread += blocksize;
1172                 }
1173                 nscan++;
1174                 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1175                         break;
1176                 if(nread > (1024 * 1024) || nscan > 128)
1177                         break;
1178
1179                 if (search < lowest_read)
1180                         lowest_read = search;
1181                 if (search > highest_read)
1182                         highest_read = search;
1183         }
1184 }
1185
1186 static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
1187 {
1188         int i;
1189         int skip_level = level;
1190         struct extent_buffer *t;
1191
1192         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1193                 if (!path->nodes[i])
1194                         break;
1195                 if (!path->locks[i])
1196                         break;
1197                 if (path->slots[i] == 0) {
1198                         skip_level = i + 1;
1199                         continue;
1200                 }
1201                 if (path->keep_locks) {
1202                         u32 nritems;
1203                         t = path->nodes[i];
1204                         nritems = btrfs_header_nritems(t);
1205                         if (path->slots[i] >= nritems - 1) {
1206                                 skip_level = i + 1;
1207                                 continue;
1208                         }
1209                 }
1210                 t = path->nodes[i];
1211                 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
1212                         btrfs_tree_unlock(t);
1213                         path->locks[i] = 0;
1214                 }
1215         }
1216 }
1217
1218 /*
1219  * look for key in the tree.  path is filled in with nodes along the way
1220  * if key is found, we return zero and you can find the item in the leaf
1221  * level of the path (level 0)
1222  *
1223  * If the key isn't found, the path points to the slot where it should
1224  * be inserted, and 1 is returned.  If there are other errors during the
1225  * search a negative error number is returned.
1226  *
1227  * if ins_len > 0, nodes and leaves will be split as we walk down the
1228  * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
1229  * possible)
1230  */
1231 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1232                       *root, struct btrfs_key *key, struct btrfs_path *p, int
1233                       ins_len, int cow)
1234 {
1235         struct extent_buffer *b;
1236         int slot;
1237         int ret;
1238         int level;
1239         int should_reada = p->reada;
1240         int lowest_unlock = 1;
1241         u8 lowest_level = 0;
1242
1243         lowest_level = p->lowest_level;
1244         WARN_ON(lowest_level && ins_len);
1245         WARN_ON(p->nodes[0] != NULL);
1246         // WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1247         WARN_ON(root == root->fs_info->extent_root &&
1248                 !mutex_is_locked(&root->fs_info->alloc_mutex));
1249         WARN_ON(root == root->fs_info->chunk_root &&
1250                 !mutex_is_locked(&root->fs_info->chunk_mutex));
1251         WARN_ON(root == root->fs_info->dev_root &&
1252                 !mutex_is_locked(&root->fs_info->chunk_mutex));
1253         if (ins_len < 0)
1254                 lowest_unlock = 2;
1255 again:
1256         if (!p->skip_locking)
1257                 b = btrfs_lock_root_node(root);
1258         else
1259                 b = btrfs_root_node(root);
1260
1261         while (b) {
1262                 level = btrfs_header_level(b);
1263                 if (cow) {
1264                         int wret;
1265                         wret = btrfs_cow_block(trans, root, b,
1266                                                p->nodes[level + 1],
1267                                                p->slots[level + 1],
1268                                                &b);
1269                         if (wret) {
1270                                 free_extent_buffer(b);
1271                                 return wret;
1272                         }
1273                 }
1274                 BUG_ON(!cow && ins_len);
1275                 if (level != btrfs_header_level(b))
1276                         WARN_ON(1);
1277                 level = btrfs_header_level(b);
1278                 p->nodes[level] = b;
1279                 if (!p->skip_locking)
1280                         p->locks[level] = 1;
1281                 ret = check_block(root, p, level);
1282                 if (ret)
1283                         return -1;
1284
1285                 ret = bin_search(b, key, level, &slot);
1286                 if (level != 0) {
1287                         if (ret && slot > 0)
1288                                 slot -= 1;
1289                         p->slots[level] = slot;
1290                         if (ins_len > 0 && btrfs_header_nritems(b) >=
1291                             BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1292                                 int sret = split_node(trans, root, p, level);
1293                                 BUG_ON(sret > 0);
1294                                 if (sret)
1295                                         return sret;
1296                                 b = p->nodes[level];
1297                                 slot = p->slots[level];
1298                         } else if (ins_len < 0) {
1299                                 int sret = balance_level(trans, root, p,
1300                                                          level);
1301                                 if (sret)
1302                                         return sret;
1303                                 b = p->nodes[level];
1304                                 if (!b) {
1305                                         btrfs_release_path(NULL, p);
1306                                         goto again;
1307                                 }
1308                                 slot = p->slots[level];
1309                                 BUG_ON(btrfs_header_nritems(b) == 1);
1310                         }
1311                         /* this is only true while dropping a snapshot */
1312                         if (level == lowest_level) {
1313                                 unlock_up(p, level, lowest_unlock);
1314                                 break;
1315                         }
1316
1317                         if (should_reada)
1318                                 reada_for_search(root, p, level, slot,
1319                                                  key->objectid);
1320
1321                         b = read_node_slot(root, b, slot);
1322                         if (!p->skip_locking)
1323                                 btrfs_tree_lock(b);
1324                         unlock_up(p, level, lowest_unlock);
1325                 } else {
1326                         p->slots[level] = slot;
1327                         if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1328                             sizeof(struct btrfs_item) + ins_len) {
1329                                 int sret = split_leaf(trans, root, key,
1330                                                       p, ins_len, ret == 0);
1331                                 BUG_ON(sret > 0);
1332                                 if (sret)
1333                                         return sret;
1334                         }
1335                         unlock_up(p, level, lowest_unlock);
1336                         return ret;
1337                 }
1338         }
1339         return 1;
1340 }
1341
1342 /*
1343  * adjust the pointers going up the tree, starting at level
1344  * making sure the right key of each node is points to 'key'.
1345  * This is used after shifting pointers to the left, so it stops
1346  * fixing up pointers when a given leaf/node is not in slot 0 of the
1347  * higher levels
1348  *
1349  * If this fails to write a tree block, it returns -1, but continues
1350  * fixing up the blocks in ram so the tree is consistent.
1351  */
1352 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1353                           struct btrfs_root *root, struct btrfs_path *path,
1354                           struct btrfs_disk_key *key, int level)
1355 {
1356         int i;
1357         int ret = 0;
1358         struct extent_buffer *t;
1359
1360         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1361                 int tslot = path->slots[i];
1362                 if (!path->nodes[i])
1363                         break;
1364                 t = path->nodes[i];
1365                 btrfs_set_node_key(t, key, tslot);
1366                 if (!btrfs_tree_locked(path->nodes[i])) {
1367                         int ii;
1368 printk("fixup without lock on level %d\n", btrfs_header_level(path->nodes[i]));
1369                         for (ii = 0; ii < BTRFS_MAX_LEVEL; ii++) {
1370 printk("level %d slot %d\n", ii, path->slots[ii]);
1371                         }
1372                 }
1373                 btrfs_mark_buffer_dirty(path->nodes[i]);
1374                 if (tslot != 0)
1375                         break;
1376         }
1377         return ret;
1378 }
1379
1380 /*
1381  * try to push data from one node into the next node left in the
1382  * tree.
1383  *
1384  * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1385  * error, and > 0 if there was no room in the left hand block.
1386  */
1387 static int push_node_left(struct btrfs_trans_handle *trans,
1388                           struct btrfs_root *root, struct extent_buffer *dst,
1389                           struct extent_buffer *src, int empty)
1390 {
1391         int push_items = 0;
1392         int src_nritems;
1393         int dst_nritems;
1394         int ret = 0;
1395
1396         src_nritems = btrfs_header_nritems(src);
1397         dst_nritems = btrfs_header_nritems(dst);
1398         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1399         WARN_ON(btrfs_header_generation(src) != trans->transid);
1400         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1401
1402         if (!empty && src_nritems <= 8)
1403                 return 1;
1404
1405         if (push_items <= 0) {
1406                 return 1;
1407         }
1408
1409         if (empty) {
1410                 push_items = min(src_nritems, push_items);
1411                 if (push_items < src_nritems) {
1412                         /* leave at least 8 pointers in the node if
1413                          * we aren't going to empty it
1414                          */
1415                         if (src_nritems - push_items < 8) {
1416                                 if (push_items <= 8)
1417                                         return 1;
1418                                 push_items -= 8;
1419                         }
1420                 }
1421         } else
1422                 push_items = min(src_nritems - 8, push_items);
1423
1424         copy_extent_buffer(dst, src,
1425                            btrfs_node_key_ptr_offset(dst_nritems),
1426                            btrfs_node_key_ptr_offset(0),
1427                            push_items * sizeof(struct btrfs_key_ptr));
1428
1429         if (push_items < src_nritems) {
1430                 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1431                                       btrfs_node_key_ptr_offset(push_items),
1432                                       (src_nritems - push_items) *
1433                                       sizeof(struct btrfs_key_ptr));
1434         }
1435         btrfs_set_header_nritems(src, src_nritems - push_items);
1436         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1437         btrfs_mark_buffer_dirty(src);
1438         btrfs_mark_buffer_dirty(dst);
1439         return ret;
1440 }
1441
1442 /*
1443  * try to push data from one node into the next node right in the
1444  * tree.
1445  *
1446  * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1447  * error, and > 0 if there was no room in the right hand block.
1448  *
1449  * this will  only push up to 1/2 the contents of the left node over
1450  */
1451 static int balance_node_right(struct btrfs_trans_handle *trans,
1452                               struct btrfs_root *root,
1453                               struct extent_buffer *dst,
1454                               struct extent_buffer *src)
1455 {
1456         int push_items = 0;
1457         int max_push;
1458         int src_nritems;
1459         int dst_nritems;
1460         int ret = 0;
1461
1462         WARN_ON(btrfs_header_generation(src) != trans->transid);
1463         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1464
1465         src_nritems = btrfs_header_nritems(src);
1466         dst_nritems = btrfs_header_nritems(dst);
1467         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1468         if (push_items <= 0) {
1469                 return 1;
1470         }
1471
1472         if (src_nritems < 4) {
1473                 return 1;
1474         }
1475
1476         max_push = src_nritems / 2 + 1;
1477         /* don't try to empty the node */
1478         if (max_push >= src_nritems) {
1479                 return 1;
1480         }
1481
1482         if (max_push < push_items)
1483                 push_items = max_push;
1484
1485         memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1486                                       btrfs_node_key_ptr_offset(0),
1487                                       (dst_nritems) *
1488                                       sizeof(struct btrfs_key_ptr));
1489
1490         copy_extent_buffer(dst, src,
1491                            btrfs_node_key_ptr_offset(0),
1492                            btrfs_node_key_ptr_offset(src_nritems - push_items),
1493                            push_items * sizeof(struct btrfs_key_ptr));
1494
1495         btrfs_set_header_nritems(src, src_nritems - push_items);
1496         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1497
1498         btrfs_mark_buffer_dirty(src);
1499         btrfs_mark_buffer_dirty(dst);
1500         return ret;
1501 }
1502
1503 /*
1504  * helper function to insert a new root level in the tree.
1505  * A new node is allocated, and a single item is inserted to
1506  * point to the existing root
1507  *
1508  * returns zero on success or < 0 on failure.
1509  */
1510 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1511                            struct btrfs_root *root,
1512                            struct btrfs_path *path, int level)
1513 {
1514         u64 root_gen;
1515         u64 lower_gen;
1516         struct extent_buffer *lower;
1517         struct extent_buffer *c;
1518         struct extent_buffer *old;
1519         struct btrfs_disk_key lower_key;
1520
1521         BUG_ON(path->nodes[level]);
1522         BUG_ON(path->nodes[level-1] != root->node);
1523
1524         if (root->ref_cows)
1525                 root_gen = trans->transid;
1526         else
1527                 root_gen = 0;
1528
1529         lower = path->nodes[level-1];
1530         if (level == 1)
1531                 btrfs_item_key(lower, &lower_key, 0);
1532         else
1533                 btrfs_node_key(lower, &lower_key, 0);
1534
1535         c = btrfs_alloc_free_block(trans, root, root->nodesize,
1536                                    root->root_key.objectid,
1537                                    root_gen, lower_key.objectid, level,
1538                                    root->node->start, 0);
1539         if (IS_ERR(c))
1540                 return PTR_ERR(c);
1541
1542         memset_extent_buffer(c, 0, 0, root->nodesize);
1543         btrfs_set_header_nritems(c, 1);
1544         btrfs_set_header_level(c, level);
1545         btrfs_set_header_bytenr(c, c->start);
1546         btrfs_set_header_generation(c, trans->transid);
1547         btrfs_set_header_owner(c, root->root_key.objectid);
1548
1549         write_extent_buffer(c, root->fs_info->fsid,
1550                             (unsigned long)btrfs_header_fsid(c),
1551                             BTRFS_FSID_SIZE);
1552
1553         write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1554                             (unsigned long)btrfs_header_chunk_tree_uuid(c),
1555                             BTRFS_UUID_SIZE);
1556
1557         btrfs_set_node_key(c, &lower_key, 0);
1558         btrfs_set_node_blockptr(c, 0, lower->start);
1559         lower_gen = btrfs_header_generation(lower);
1560         WARN_ON(lower_gen == 0);
1561
1562         btrfs_set_node_ptr_generation(c, 0, lower_gen);
1563
1564         btrfs_mark_buffer_dirty(c);
1565
1566         spin_lock(&root->node_lock);
1567         old = root->node;
1568         root->node = c;
1569         spin_unlock(&root->node_lock);
1570
1571         /* the super has an extra ref to root->node */
1572         free_extent_buffer(old);
1573
1574         add_root_to_dirty_list(root);
1575         extent_buffer_get(c);
1576         path->nodes[level] = c;
1577         path->locks[level] = 1;
1578         path->slots[level] = 0;
1579
1580         if (root->ref_cows && lower_gen != trans->transid) {
1581                 struct btrfs_path *back_path = btrfs_alloc_path();
1582                 int ret;
1583                 mutex_lock(&root->fs_info->alloc_mutex);
1584                 ret = btrfs_insert_extent_backref(trans,
1585                                                   root->fs_info->extent_root,
1586                                                   path, lower->start,
1587                                                   root->root_key.objectid,
1588                                                   trans->transid, 0, 0);
1589                 BUG_ON(ret);
1590                 mutex_unlock(&root->fs_info->alloc_mutex);
1591                 btrfs_free_path(back_path);
1592         }
1593         return 0;
1594 }
1595
1596 /*
1597  * worker function to insert a single pointer in a node.
1598  * the node should have enough room for the pointer already
1599  *
1600  * slot and level indicate where you want the key to go, and
1601  * blocknr is the block the key points to.
1602  *
1603  * returns zero on success and < 0 on any error
1604  */
1605 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1606                       *root, struct btrfs_path *path, struct btrfs_disk_key
1607                       *key, u64 bytenr, int slot, int level)
1608 {
1609         struct extent_buffer *lower;
1610         int nritems;
1611
1612         BUG_ON(!path->nodes[level]);
1613         lower = path->nodes[level];
1614         nritems = btrfs_header_nritems(lower);
1615         if (slot > nritems)
1616                 BUG();
1617         if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1618                 BUG();
1619         if (slot != nritems) {
1620                 memmove_extent_buffer(lower,
1621                               btrfs_node_key_ptr_offset(slot + 1),
1622                               btrfs_node_key_ptr_offset(slot),
1623                               (nritems - slot) * sizeof(struct btrfs_key_ptr));
1624         }
1625         btrfs_set_node_key(lower, key, slot);
1626         btrfs_set_node_blockptr(lower, slot, bytenr);
1627         WARN_ON(trans->transid == 0);
1628         btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1629         btrfs_set_header_nritems(lower, nritems + 1);
1630         btrfs_mark_buffer_dirty(lower);
1631         return 0;
1632 }
1633
1634 /*
1635  * split the node at the specified level in path in two.
1636  * The path is corrected to point to the appropriate node after the split
1637  *
1638  * Before splitting this tries to make some room in the node by pushing
1639  * left and right, if either one works, it returns right away.
1640  *
1641  * returns 0 on success and < 0 on failure
1642  */
1643 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1644                       *root, struct btrfs_path *path, int level)
1645 {
1646         u64 root_gen;
1647         struct extent_buffer *c;
1648         struct extent_buffer *split;
1649         struct btrfs_disk_key disk_key;
1650         int mid;
1651         int ret;
1652         int wret;
1653         u32 c_nritems;
1654
1655         c = path->nodes[level];
1656         WARN_ON(btrfs_header_generation(c) != trans->transid);
1657         if (c == root->node) {
1658                 /* trying to split the root, lets make a new one */
1659                 ret = insert_new_root(trans, root, path, level + 1);
1660                 if (ret)
1661                         return ret;
1662         } else {
1663                 ret = push_nodes_for_insert(trans, root, path, level);
1664                 c = path->nodes[level];
1665                 if (!ret && btrfs_header_nritems(c) <
1666                     BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1667                         return 0;
1668                 if (ret < 0)
1669                         return ret;
1670         }
1671
1672         c_nritems = btrfs_header_nritems(c);
1673         if (root->ref_cows)
1674                 root_gen = trans->transid;
1675         else
1676                 root_gen = 0;
1677
1678         btrfs_node_key(c, &disk_key, 0);
1679         split = btrfs_alloc_free_block(trans, root, root->nodesize,
1680                                          root->root_key.objectid,
1681                                          root_gen,
1682                                          btrfs_disk_key_objectid(&disk_key),
1683                                          level, c->start, 0);
1684         if (IS_ERR(split))
1685                 return PTR_ERR(split);
1686
1687         btrfs_set_header_flags(split, btrfs_header_flags(c));
1688         btrfs_set_header_level(split, btrfs_header_level(c));
1689         btrfs_set_header_bytenr(split, split->start);
1690         btrfs_set_header_generation(split, trans->transid);
1691         btrfs_set_header_owner(split, root->root_key.objectid);
1692         btrfs_set_header_flags(split, 0);
1693         write_extent_buffer(split, root->fs_info->fsid,
1694                             (unsigned long)btrfs_header_fsid(split),
1695                             BTRFS_FSID_SIZE);
1696         write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1697                             (unsigned long)btrfs_header_chunk_tree_uuid(split),
1698                             BTRFS_UUID_SIZE);
1699
1700         mid = (c_nritems + 1) / 2;
1701
1702         copy_extent_buffer(split, c,
1703                            btrfs_node_key_ptr_offset(0),
1704                            btrfs_node_key_ptr_offset(mid),
1705                            (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1706         btrfs_set_header_nritems(split, c_nritems - mid);
1707         btrfs_set_header_nritems(c, mid);
1708         ret = 0;
1709
1710         btrfs_mark_buffer_dirty(c);
1711         btrfs_mark_buffer_dirty(split);
1712
1713         btrfs_node_key(split, &disk_key, 0);
1714         wret = insert_ptr(trans, root, path, &disk_key, split->start,
1715                           path->slots[level + 1] + 1,
1716                           level + 1);
1717         if (wret)
1718                 ret = wret;
1719
1720         if (path->slots[level] >= mid) {
1721                 path->slots[level] -= mid;
1722                 btrfs_tree_unlock(c);
1723                 free_extent_buffer(c);
1724                 path->nodes[level] = split;
1725                 path->slots[level + 1] += 1;
1726         } else {
1727                 btrfs_tree_unlock(split);
1728                 free_extent_buffer(split);
1729         }
1730         return ret;
1731 }
1732
1733 /*
1734  * how many bytes are required to store the items in a leaf.  start
1735  * and nr indicate which items in the leaf to check.  This totals up the
1736  * space used both by the item structs and the item data
1737  */
1738 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1739 {
1740         int data_len;
1741         int nritems = btrfs_header_nritems(l);
1742         int end = min(nritems, start + nr) - 1;
1743
1744         if (!nr)
1745                 return 0;
1746         data_len = btrfs_item_end_nr(l, start);
1747         data_len = data_len - btrfs_item_offset_nr(l, end);
1748         data_len += sizeof(struct btrfs_item) * nr;
1749         WARN_ON(data_len < 0);
1750         return data_len;
1751 }
1752
1753 /*
1754  * The space between the end of the leaf items and
1755  * the start of the leaf data.  IOW, how much room
1756  * the leaf has left for both items and data
1757  */
1758 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1759 {
1760         int nritems = btrfs_header_nritems(leaf);
1761         int ret;
1762         ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1763         if (ret < 0) {
1764                 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1765                        ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1766                        leaf_space_used(leaf, 0, nritems), nritems);
1767         }
1768         return ret;
1769 }
1770
1771 /*
1772  * push some data in the path leaf to the right, trying to free up at
1773  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1774  *
1775  * returns 1 if the push failed because the other node didn't have enough
1776  * room, 0 if everything worked out and < 0 if there were major errors.
1777  */
1778 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1779                            *root, struct btrfs_path *path, int data_size,
1780                            int empty)
1781 {
1782         struct extent_buffer *left = path->nodes[0];
1783         struct extent_buffer *right;
1784         struct extent_buffer *upper;
1785         struct btrfs_disk_key disk_key;
1786         int slot;
1787         u32 i;
1788         int free_space;
1789         int push_space = 0;
1790         int push_items = 0;
1791         struct btrfs_item *item;
1792         u32 left_nritems;
1793         u32 nr;
1794         u32 right_nritems;
1795         u32 data_end;
1796         u32 this_item_size;
1797         int ret;
1798
1799         slot = path->slots[1];
1800         if (!path->nodes[1]) {
1801                 return 1;
1802         }
1803         upper = path->nodes[1];
1804         if (slot >= btrfs_header_nritems(upper) - 1)
1805                 return 1;
1806
1807         right = read_node_slot(root, upper, slot + 1);
1808         btrfs_tree_lock(right);
1809         free_space = btrfs_leaf_free_space(root, right);
1810         if (free_space < data_size + sizeof(struct btrfs_item))
1811                 goto out_unlock;
1812
1813         /* cow and double check */
1814         ret = btrfs_cow_block(trans, root, right, upper,
1815                               slot + 1, &right);
1816         if (ret)
1817                 goto out_unlock;
1818
1819         free_space = btrfs_leaf_free_space(root, right);
1820         if (free_space < data_size + sizeof(struct btrfs_item))
1821                 goto out_unlock;
1822
1823         left_nritems = btrfs_header_nritems(left);
1824         if (left_nritems == 0)
1825                 goto out_unlock;
1826
1827         if (empty)
1828                 nr = 0;
1829         else
1830                 nr = 1;
1831
1832         i = left_nritems - 1;
1833         while (i >= nr) {
1834                 item = btrfs_item_nr(left, i);
1835
1836                 if (path->slots[0] == i)
1837                         push_space += data_size + sizeof(*item);
1838
1839                 if (!left->map_token) {
1840                         map_extent_buffer(left, (unsigned long)item,
1841                                         sizeof(struct btrfs_item),
1842                                         &left->map_token, &left->kaddr,
1843                                         &left->map_start, &left->map_len,
1844                                         KM_USER1);
1845                 }
1846
1847                 this_item_size = btrfs_item_size(left, item);
1848                 if (this_item_size + sizeof(*item) + push_space > free_space)
1849                         break;
1850                 push_items++;
1851                 push_space += this_item_size + sizeof(*item);
1852                 if (i == 0)
1853                         break;
1854                 i--;
1855         }
1856         if (left->map_token) {
1857                 unmap_extent_buffer(left, left->map_token, KM_USER1);
1858                 left->map_token = NULL;
1859         }
1860
1861         if (push_items == 0)
1862                 goto out_unlock;
1863
1864         if (!empty && push_items == left_nritems)
1865                 WARN_ON(1);
1866
1867         /* push left to right */
1868         right_nritems = btrfs_header_nritems(right);
1869
1870         push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1871         push_space -= leaf_data_end(root, left);
1872
1873         /* make room in the right data area */
1874         data_end = leaf_data_end(root, right);
1875         memmove_extent_buffer(right,
1876                               btrfs_leaf_data(right) + data_end - push_space,
1877                               btrfs_leaf_data(right) + data_end,
1878                               BTRFS_LEAF_DATA_SIZE(root) - data_end);
1879
1880         /* copy from the left data area */
1881         copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1882                      BTRFS_LEAF_DATA_SIZE(root) - push_space,
1883                      btrfs_leaf_data(left) + leaf_data_end(root, left),
1884                      push_space);
1885
1886         memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1887                               btrfs_item_nr_offset(0),
1888                               right_nritems * sizeof(struct btrfs_item));
1889
1890         /* copy the items from left to right */
1891         copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1892                    btrfs_item_nr_offset(left_nritems - push_items),
1893                    push_items * sizeof(struct btrfs_item));
1894
1895         /* update the item pointers */
1896         right_nritems += push_items;
1897         btrfs_set_header_nritems(right, right_nritems);
1898         push_space = BTRFS_LEAF_DATA_SIZE(root);
1899         for (i = 0; i < right_nritems; i++) {
1900                 item = btrfs_item_nr(right, i);
1901                 if (!right->map_token) {
1902                         map_extent_buffer(right, (unsigned long)item,
1903                                         sizeof(struct btrfs_item),
1904                                         &right->map_token, &right->kaddr,
1905                                         &right->map_start, &right->map_len,
1906                                         KM_USER1);
1907                 }
1908                 push_space -= btrfs_item_size(right, item);
1909                 btrfs_set_item_offset(right, item, push_space);
1910         }
1911
1912         if (right->map_token) {
1913                 unmap_extent_buffer(right, right->map_token, KM_USER1);
1914                 right->map_token = NULL;
1915         }
1916         left_nritems -= push_items;
1917         btrfs_set_header_nritems(left, left_nritems);
1918
1919         if (left_nritems)
1920                 btrfs_mark_buffer_dirty(left);
1921         btrfs_mark_buffer_dirty(right);
1922
1923         btrfs_item_key(right, &disk_key, 0);
1924         btrfs_set_node_key(upper, &disk_key, slot + 1);
1925         btrfs_mark_buffer_dirty(upper);
1926
1927         /* then fixup the leaf pointer in the path */
1928         if (path->slots[0] >= left_nritems) {
1929                 path->slots[0] -= left_nritems;
1930                 if (btrfs_header_nritems(path->nodes[0]) == 0)
1931                         clean_tree_block(trans, root, path->nodes[0]);
1932                 btrfs_tree_unlock(path->nodes[0]);
1933                 free_extent_buffer(path->nodes[0]);
1934                 path->nodes[0] = right;
1935                 path->slots[1] += 1;
1936         } else {
1937                 btrfs_tree_unlock(right);
1938                 free_extent_buffer(right);
1939         }
1940         return 0;
1941
1942 out_unlock:
1943         btrfs_tree_unlock(right);
1944         free_extent_buffer(right);
1945         return 1;
1946 }
1947
1948 /*
1949  * push some data in the path leaf to the left, trying to free up at
1950  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1951  */
1952 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1953                           *root, struct btrfs_path *path, int data_size,
1954                           int empty)
1955 {
1956         struct btrfs_disk_key disk_key;
1957         struct extent_buffer *right = path->nodes[0];
1958         struct extent_buffer *left;
1959         int slot;
1960         int i;
1961         int free_space;
1962         int push_space = 0;
1963         int push_items = 0;
1964         struct btrfs_item *item;
1965         u32 old_left_nritems;
1966         u32 right_nritems;
1967         u32 nr;
1968         int ret = 0;
1969         int wret;
1970         u32 this_item_size;
1971         u32 old_left_item_size;
1972
1973         slot = path->slots[1];
1974         if (slot == 0)
1975                 return 1;
1976         if (!path->nodes[1])
1977                 return 1;
1978
1979         right_nritems = btrfs_header_nritems(right);
1980         if (right_nritems == 0) {
1981                 return 1;
1982         }
1983
1984         left = read_node_slot(root, path->nodes[1], slot - 1);
1985         btrfs_tree_lock(left);
1986         free_space = btrfs_leaf_free_space(root, left);
1987         if (free_space < data_size + sizeof(struct btrfs_item)) {
1988                 ret = 1;
1989                 goto out;
1990         }
1991
1992         /* cow and double check */
1993         ret = btrfs_cow_block(trans, root, left,
1994                               path->nodes[1], slot - 1, &left);
1995         if (ret) {
1996                 /* we hit -ENOSPC, but it isn't fatal here */
1997                 ret = 1;
1998                 goto out;
1999         }
2000
2001         free_space = btrfs_leaf_free_space(root, left);
2002         if (free_space < data_size + sizeof(struct btrfs_item)) {
2003                 ret = 1;
2004                 goto out;
2005         }
2006
2007         if (empty)
2008                 nr = right_nritems;
2009         else
2010                 nr = right_nritems - 1;
2011
2012         for (i = 0; i < nr; i++) {
2013                 item = btrfs_item_nr(right, i);
2014                 if (!right->map_token) {
2015                         map_extent_buffer(right, (unsigned long)item,
2016                                         sizeof(struct btrfs_item),
2017                                         &right->map_token, &right->kaddr,
2018                                         &right->map_start, &right->map_len,
2019                                         KM_USER1);
2020                 }
2021
2022                 if (path->slots[0] == i)
2023                         push_space += data_size + sizeof(*item);
2024
2025                 this_item_size = btrfs_item_size(right, item);
2026                 if (this_item_size + sizeof(*item) + push_space > free_space)
2027                         break;
2028
2029                 push_items++;
2030                 push_space += this_item_size + sizeof(*item);
2031         }
2032
2033         if (right->map_token) {
2034                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2035                 right->map_token = NULL;
2036         }
2037
2038         if (push_items == 0) {
2039                 ret = 1;
2040                 goto out;
2041         }
2042         if (!empty && push_items == btrfs_header_nritems(right))
2043                 WARN_ON(1);
2044
2045         /* push data from right to left */
2046         copy_extent_buffer(left, right,
2047                            btrfs_item_nr_offset(btrfs_header_nritems(left)),
2048                            btrfs_item_nr_offset(0),
2049                            push_items * sizeof(struct btrfs_item));
2050
2051         push_space = BTRFS_LEAF_DATA_SIZE(root) -
2052                      btrfs_item_offset_nr(right, push_items -1);
2053
2054         copy_extent_buffer(left, right, btrfs_leaf_data(left) +
2055                      leaf_data_end(root, left) - push_space,
2056                      btrfs_leaf_data(right) +
2057                      btrfs_item_offset_nr(right, push_items - 1),
2058                      push_space);
2059         old_left_nritems = btrfs_header_nritems(left);
2060         BUG_ON(old_left_nritems < 0);
2061
2062         old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
2063         for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
2064                 u32 ioff;
2065
2066                 item = btrfs_item_nr(left, i);
2067                 if (!left->map_token) {
2068                         map_extent_buffer(left, (unsigned long)item,
2069                                         sizeof(struct btrfs_item),
2070                                         &left->map_token, &left->kaddr,
2071                                         &left->map_start, &left->map_len,
2072                                         KM_USER1);
2073                 }
2074
2075                 ioff = btrfs_item_offset(left, item);
2076                 btrfs_set_item_offset(left, item,
2077                       ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
2078         }
2079         btrfs_set_header_nritems(left, old_left_nritems + push_items);
2080         if (left->map_token) {
2081                 unmap_extent_buffer(left, left->map_token, KM_USER1);
2082                 left->map_token = NULL;
2083         }
2084
2085         /* fixup right node */
2086         if (push_items > right_nritems) {
2087                 printk("push items %d nr %u\n", push_items, right_nritems);
2088                 WARN_ON(1);
2089         }
2090
2091         if (push_items < right_nritems) {
2092                 push_space = btrfs_item_offset_nr(right, push_items - 1) -
2093                                                   leaf_data_end(root, right);
2094                 memmove_extent_buffer(right, btrfs_leaf_data(right) +
2095                                       BTRFS_LEAF_DATA_SIZE(root) - push_space,
2096                                       btrfs_leaf_data(right) +
2097                                       leaf_data_end(root, right), push_space);
2098
2099                 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
2100                               btrfs_item_nr_offset(push_items),
2101                              (btrfs_header_nritems(right) - push_items) *
2102                              sizeof(struct btrfs_item));
2103         }
2104         right_nritems -= push_items;
2105         btrfs_set_header_nritems(right, right_nritems);
2106         push_space = BTRFS_LEAF_DATA_SIZE(root);
2107         for (i = 0; i < right_nritems; i++) {
2108                 item = btrfs_item_nr(right, i);
2109
2110                 if (!right->map_token) {
2111                         map_extent_buffer(right, (unsigned long)item,
2112                                         sizeof(struct btrfs_item),
2113                                         &right->map_token, &right->kaddr,
2114                                         &right->map_start, &right->map_len,
2115                                         KM_USER1);
2116                 }
2117
2118                 push_space = push_space - btrfs_item_size(right, item);
2119                 btrfs_set_item_offset(right, item, push_space);
2120         }
2121         if (right->map_token) {
2122                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2123                 right->map_token = NULL;
2124         }
2125
2126         btrfs_mark_buffer_dirty(left);
2127         if (right_nritems)
2128                 btrfs_mark_buffer_dirty(right);
2129
2130         btrfs_item_key(right, &disk_key, 0);
2131         wret = fixup_low_keys(trans, root, path, &disk_key, 1);
2132         if (wret)
2133                 ret = wret;
2134
2135         /* then fixup the leaf pointer in the path */
2136         if (path->slots[0] < push_items) {
2137                 path->slots[0] += old_left_nritems;
2138                 if (btrfs_header_nritems(path->nodes[0]) == 0)
2139                         clean_tree_block(trans, root, path->nodes[0]);
2140                 btrfs_tree_unlock(path->nodes[0]);
2141                 free_extent_buffer(path->nodes[0]);
2142                 path->nodes[0] = left;
2143                 path->slots[1] -= 1;
2144         } else {
2145                 btrfs_tree_unlock(left);
2146                 free_extent_buffer(left);
2147                 path->slots[0] -= push_items;
2148         }
2149         BUG_ON(path->slots[0] < 0);
2150         return ret;
2151 out:
2152         btrfs_tree_unlock(left);
2153         free_extent_buffer(left);
2154         return ret;
2155 }
2156
2157 /*
2158  * split the path's leaf in two, making sure there is at least data_size
2159  * available for the resulting leaf level of the path.
2160  *
2161  * returns 0 if all went well and < 0 on failure.
2162  */
2163 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
2164                       *root, struct btrfs_key *ins_key,
2165                       struct btrfs_path *path, int data_size, int extend)
2166 {
2167         u64 root_gen;
2168         struct extent_buffer *l;
2169         u32 nritems;
2170         int mid;
2171         int slot;
2172         struct extent_buffer *right;
2173         int space_needed = data_size + sizeof(struct btrfs_item);
2174         int data_copy_size;
2175         int rt_data_off;
2176         int i;
2177         int ret = 0;
2178         int wret;
2179         int double_split;
2180         int num_doubles = 0;
2181         struct btrfs_disk_key disk_key;
2182
2183         if (extend)
2184                 space_needed = data_size;
2185
2186         if (root->ref_cows)
2187                 root_gen = trans->transid;
2188         else
2189                 root_gen = 0;
2190
2191         /* first try to make some room by pushing left and right */
2192         if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
2193                 wret = push_leaf_right(trans, root, path, data_size, 0);
2194                 if (wret < 0) {
2195                         return wret;
2196                 }
2197                 if (wret) {
2198                         wret = push_leaf_left(trans, root, path, data_size, 0);
2199                         if (wret < 0)
2200                                 return wret;
2201                 }
2202                 l = path->nodes[0];
2203
2204                 /* did the pushes work? */
2205                 if (btrfs_leaf_free_space(root, l) >= space_needed)
2206                         return 0;
2207         }
2208
2209         if (!path->nodes[1]) {
2210                 ret = insert_new_root(trans, root, path, 1);
2211                 if (ret)
2212                         return ret;
2213         }
2214 again:
2215         double_split = 0;
2216         l = path->nodes[0];
2217         slot = path->slots[0];
2218         nritems = btrfs_header_nritems(l);
2219         mid = (nritems + 1)/ 2;
2220
2221         btrfs_item_key(l, &disk_key, 0);
2222
2223         right = btrfs_alloc_free_block(trans, root, root->leafsize,
2224                                          root->root_key.objectid,
2225                                          root_gen, disk_key.objectid, 0,
2226                                          l->start, 0);
2227         if (IS_ERR(right)) {
2228                 BUG_ON(1);
2229                 return PTR_ERR(right);
2230         }
2231
2232         memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2233         btrfs_set_header_bytenr(right, right->start);
2234         btrfs_set_header_generation(right, trans->transid);
2235         btrfs_set_header_owner(right, root->root_key.objectid);
2236         btrfs_set_header_level(right, 0);
2237         write_extent_buffer(right, root->fs_info->fsid,
2238                             (unsigned long)btrfs_header_fsid(right),
2239                             BTRFS_FSID_SIZE);
2240
2241         write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2242                             (unsigned long)btrfs_header_chunk_tree_uuid(right),
2243                             BTRFS_UUID_SIZE);
2244         if (mid <= slot) {
2245                 if (nritems == 1 ||
2246                     leaf_space_used(l, mid, nritems - mid) + space_needed >
2247                         BTRFS_LEAF_DATA_SIZE(root)) {
2248                         if (slot >= nritems) {
2249                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2250                                 btrfs_set_header_nritems(right, 0);
2251                                 wret = insert_ptr(trans, root, path,
2252                                                   &disk_key, right->start,
2253                                                   path->slots[1] + 1, 1);
2254                                 if (wret)
2255                                         ret = wret;
2256
2257                                 btrfs_tree_unlock(path->nodes[0]);
2258                                 free_extent_buffer(path->nodes[0]);
2259                                 path->nodes[0] = right;
2260                                 path->slots[0] = 0;
2261                                 path->slots[1] += 1;
2262                                 btrfs_mark_buffer_dirty(right);
2263                                 return ret;
2264                         }
2265                         mid = slot;
2266                         if (mid != nritems &&
2267                             leaf_space_used(l, mid, nritems - mid) +
2268                             space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2269                                 double_split = 1;
2270                         }
2271                 }
2272         } else {
2273                 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2274                         BTRFS_LEAF_DATA_SIZE(root)) {
2275                         if (!extend && slot == 0) {
2276                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2277                                 btrfs_set_header_nritems(right, 0);
2278                                 wret = insert_ptr(trans, root, path,
2279                                                   &disk_key,
2280                                                   right->start,
2281                                                   path->slots[1], 1);
2282                                 if (wret)
2283                                         ret = wret;
2284                                 btrfs_tree_unlock(path->nodes[0]);
2285                                 free_extent_buffer(path->nodes[0]);
2286                                 path->nodes[0] = right;
2287                                 path->slots[0] = 0;
2288                                 if (path->slots[1] == 0) {
2289                                         wret = fixup_low_keys(trans, root,
2290                                                    path, &disk_key, 1);
2291                                         if (wret)
2292                                                 ret = wret;
2293                                 }
2294                                 btrfs_mark_buffer_dirty(right);
2295                                 return ret;
2296                         } else if (extend && slot == 0) {
2297                                 mid = 1;
2298                         } else {
2299                                 mid = slot;
2300                                 if (mid != nritems &&
2301                                     leaf_space_used(l, mid, nritems - mid) +
2302                                     space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2303                                         double_split = 1;
2304                                 }
2305                         }
2306                 }
2307         }
2308         nritems = nritems - mid;
2309         btrfs_set_header_nritems(right, nritems);
2310         data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2311
2312         copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2313                            btrfs_item_nr_offset(mid),
2314                            nritems * sizeof(struct btrfs_item));
2315
2316         copy_extent_buffer(right, l,
2317                      btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2318                      data_copy_size, btrfs_leaf_data(l) +
2319                      leaf_data_end(root, l), data_copy_size);
2320
2321         rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2322                       btrfs_item_end_nr(l, mid);
2323
2324         for (i = 0; i < nritems; i++) {
2325                 struct btrfs_item *item = btrfs_item_nr(right, i);
2326                 u32 ioff;
2327
2328                 if (!right->map_token) {
2329                         map_extent_buffer(right, (unsigned long)item,
2330                                         sizeof(struct btrfs_item),
2331                                         &right->map_token, &right->kaddr,
2332                                         &right->map_start, &right->map_len,
2333                                         KM_USER1);
2334                 }
2335
2336                 ioff = btrfs_item_offset(right, item);
2337                 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2338         }
2339
2340         if (right->map_token) {
2341                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2342                 right->map_token = NULL;
2343         }
2344
2345         btrfs_set_header_nritems(l, mid);
2346         ret = 0;
2347         btrfs_item_key(right, &disk_key, 0);
2348         wret = insert_ptr(trans, root, path, &disk_key, right->start,
2349                           path->slots[1] + 1, 1);
2350         if (wret)
2351                 ret = wret;
2352
2353         btrfs_mark_buffer_dirty(right);
2354         btrfs_mark_buffer_dirty(l);
2355         BUG_ON(path->slots[0] != slot);
2356
2357         if (mid <= slot) {
2358                 btrfs_tree_unlock(path->nodes[0]);
2359                 free_extent_buffer(path->nodes[0]);
2360                 path->nodes[0] = right;
2361                 path->slots[0] -= mid;
2362                 path->slots[1] += 1;
2363         } else {
2364                 btrfs_tree_unlock(right);
2365                 free_extent_buffer(right);
2366         }
2367
2368         BUG_ON(path->slots[0] < 0);
2369
2370         if (double_split) {
2371                 BUG_ON(num_doubles != 0);
2372                 num_doubles++;
2373                 goto again;
2374         }
2375         return ret;
2376 }
2377
2378 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2379                         struct btrfs_root *root,
2380                         struct btrfs_path *path,
2381                         u32 new_size, int from_end)
2382 {
2383         int ret = 0;
2384         int slot;
2385         int slot_orig;
2386         struct extent_buffer *leaf;
2387         struct btrfs_item *item;
2388         u32 nritems;
2389         unsigned int data_end;
2390         unsigned int old_data_start;
2391         unsigned int old_size;
2392         unsigned int size_diff;
2393         int i;
2394
2395         slot_orig = path->slots[0];
2396         leaf = path->nodes[0];
2397         slot = path->slots[0];
2398
2399         old_size = btrfs_item_size_nr(leaf, slot);
2400         if (old_size == new_size)
2401                 return 0;
2402
2403         nritems = btrfs_header_nritems(leaf);
2404         data_end = leaf_data_end(root, leaf);
2405
2406         old_data_start = btrfs_item_offset_nr(leaf, slot);
2407
2408         size_diff = old_size - new_size;
2409
2410         BUG_ON(slot < 0);
2411         BUG_ON(slot >= nritems);
2412
2413         /*
2414          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2415          */
2416         /* first correct the data pointers */
2417         for (i = slot; i < nritems; i++) {
2418                 u32 ioff;
2419                 item = btrfs_item_nr(leaf, i);
2420
2421                 if (!leaf->map_token) {
2422                         map_extent_buffer(leaf, (unsigned long)item,
2423                                         sizeof(struct btrfs_item),
2424                                         &leaf->map_token, &leaf->kaddr,
2425                                         &leaf->map_start, &leaf->map_len,
2426                                         KM_USER1);
2427                 }
2428
2429                 ioff = btrfs_item_offset(leaf, item);
2430                 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2431         }
2432
2433         if (leaf->map_token) {
2434                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2435                 leaf->map_token = NULL;
2436         }
2437
2438         /* shift the data */
2439         if (from_end) {
2440                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2441                               data_end + size_diff, btrfs_leaf_data(leaf) +
2442                               data_end, old_data_start + new_size - data_end);
2443         } else {
2444                 struct btrfs_disk_key disk_key;
2445                 u64 offset;
2446
2447                 btrfs_item_key(leaf, &disk_key, slot);
2448
2449                 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2450                         unsigned long ptr;
2451                         struct btrfs_file_extent_item *fi;
2452
2453                         fi = btrfs_item_ptr(leaf, slot,
2454                                             struct btrfs_file_extent_item);
2455                         fi = (struct btrfs_file_extent_item *)(
2456                              (unsigned long)fi - size_diff);
2457
2458                         if (btrfs_file_extent_type(leaf, fi) ==
2459                             BTRFS_FILE_EXTENT_INLINE) {
2460                                 ptr = btrfs_item_ptr_offset(leaf, slot);
2461                                 memmove_extent_buffer(leaf, ptr,
2462                                         (unsigned long)fi,
2463                                         offsetof(struct btrfs_file_extent_item,
2464                                                  disk_bytenr));
2465                         }
2466                 }
2467
2468                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2469                               data_end + size_diff, btrfs_leaf_data(leaf) +
2470                               data_end, old_data_start - data_end);
2471
2472                 offset = btrfs_disk_key_offset(&disk_key);
2473                 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2474                 btrfs_set_item_key(leaf, &disk_key, slot);
2475                 if (slot == 0)
2476                         fixup_low_keys(trans, root, path, &disk_key, 1);
2477         }
2478
2479         item = btrfs_item_nr(leaf, slot);
2480         btrfs_set_item_size(leaf, item, new_size);
2481         btrfs_mark_buffer_dirty(leaf);
2482
2483         ret = 0;
2484         if (btrfs_leaf_free_space(root, leaf) < 0) {
2485                 btrfs_print_leaf(root, leaf);
2486                 BUG();
2487         }
2488         return ret;
2489 }
2490
2491 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2492                       struct btrfs_root *root, struct btrfs_path *path,
2493                       u32 data_size)
2494 {
2495         int ret = 0;
2496         int slot;
2497         int slot_orig;
2498         struct extent_buffer *leaf;
2499         struct btrfs_item *item;
2500         u32 nritems;
2501         unsigned int data_end;
2502         unsigned int old_data;
2503         unsigned int old_size;
2504         int i;
2505
2506         slot_orig = path->slots[0];
2507         leaf = path->nodes[0];
2508
2509         nritems = btrfs_header_nritems(leaf);
2510         data_end = leaf_data_end(root, leaf);
2511
2512         if (btrfs_leaf_free_space(root, leaf) < data_size) {
2513                 btrfs_print_leaf(root, leaf);
2514                 BUG();
2515         }
2516         slot = path->slots[0];
2517         old_data = btrfs_item_end_nr(leaf, slot);
2518
2519         BUG_ON(slot < 0);
2520         if (slot >= nritems) {
2521                 btrfs_print_leaf(root, leaf);
2522                 printk("slot %d too large, nritems %d\n", slot, nritems);
2523                 BUG_ON(1);
2524         }
2525
2526         /*
2527          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2528          */
2529         /* first correct the data pointers */
2530         for (i = slot; i < nritems; i++) {
2531                 u32 ioff;
2532                 item = btrfs_item_nr(leaf, i);
2533
2534                 if (!leaf->map_token) {
2535                         map_extent_buffer(leaf, (unsigned long)item,
2536                                         sizeof(struct btrfs_item),
2537                                         &leaf->map_token, &leaf->kaddr,
2538                                         &leaf->map_start, &leaf->map_len,
2539                                         KM_USER1);
2540                 }
2541                 ioff = btrfs_item_offset(leaf, item);
2542                 btrfs_set_item_offset(leaf, item, ioff - data_size);
2543         }
2544
2545         if (leaf->map_token) {
2546                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2547                 leaf->map_token = NULL;
2548         }
2549
2550         /* shift the data */
2551         memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2552                       data_end - data_size, btrfs_leaf_data(leaf) +
2553                       data_end, old_data - data_end);
2554
2555         data_end = old_data;
2556         old_size = btrfs_item_size_nr(leaf, slot);
2557         item = btrfs_item_nr(leaf, slot);
2558         btrfs_set_item_size(leaf, item, old_size + data_size);
2559         btrfs_mark_buffer_dirty(leaf);
2560
2561         ret = 0;
2562         if (btrfs_leaf_free_space(root, leaf) < 0) {
2563                 btrfs_print_leaf(root, leaf);
2564                 BUG();
2565         }
2566         return ret;
2567 }
2568
2569 /*
2570  * Given a key and some data, insert an item into the tree.
2571  * This does all the path init required, making room in the tree if needed.
2572  */
2573 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2574                             struct btrfs_root *root,
2575                             struct btrfs_path *path,
2576                             struct btrfs_key *cpu_key, u32 *data_size,
2577                             int nr)
2578 {
2579         struct extent_buffer *leaf;
2580         struct btrfs_item *item;
2581         int ret = 0;
2582         int slot;
2583         int slot_orig;
2584         int i;
2585         u32 nritems;
2586         u32 total_size = 0;
2587         u32 total_data = 0;
2588         unsigned int data_end;
2589         struct btrfs_disk_key disk_key;
2590
2591         for (i = 0; i < nr; i++) {
2592                 total_data += data_size[i];
2593         }
2594
2595         total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2596         ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2597         if (ret == 0) {
2598                 return -EEXIST;
2599         }
2600         if (ret < 0)
2601                 goto out;
2602
2603         slot_orig = path->slots[0];
2604         leaf = path->nodes[0];
2605
2606         nritems = btrfs_header_nritems(leaf);
2607         data_end = leaf_data_end(root, leaf);
2608
2609         if (btrfs_leaf_free_space(root, leaf) <
2610             sizeof(struct btrfs_item) + total_size) {
2611                 btrfs_print_leaf(root, leaf);
2612                 printk("not enough freespace need %u have %d\n",
2613                        total_size, btrfs_leaf_free_space(root, leaf));
2614                 BUG();
2615         }
2616
2617         slot = path->slots[0];
2618         BUG_ON(slot < 0);
2619
2620         if (slot != nritems) {
2621                 int i;
2622                 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2623
2624                 if (old_data < data_end) {
2625                         btrfs_print_leaf(root, leaf);
2626                         printk("slot %d old_data %d data_end %d\n",
2627                                slot, old_data, data_end);
2628                         BUG_ON(1);
2629                 }
2630                 /*
2631                  * item0..itemN ... dataN.offset..dataN.size .. data0.size
2632                  */
2633                 /* first correct the data pointers */
2634                 WARN_ON(leaf->map_token);
2635                 for (i = slot; i < nritems; i++) {
2636                         u32 ioff;
2637
2638                         item = btrfs_item_nr(leaf, i);
2639                         if (!leaf->map_token) {
2640                                 map_extent_buffer(leaf, (unsigned long)item,
2641                                         sizeof(struct btrfs_item),
2642                                         &leaf->map_token, &leaf->kaddr,
2643                                         &leaf->map_start, &leaf->map_len,
2644                                         KM_USER1);
2645                         }
2646
2647                         ioff = btrfs_item_offset(leaf, item);
2648                         btrfs_set_item_offset(leaf, item, ioff - total_data);
2649                 }
2650                 if (leaf->map_token) {
2651                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2652                         leaf->map_token = NULL;
2653                 }
2654
2655                 /* shift the items */
2656                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2657                               btrfs_item_nr_offset(slot),
2658                               (nritems - slot) * sizeof(struct btrfs_item));
2659
2660                 /* shift the data */
2661                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2662                               data_end - total_data, btrfs_leaf_data(leaf) +
2663                               data_end, old_data - data_end);
2664                 data_end = old_data;
2665         }
2666
2667         /* setup the item for the new data */
2668         for (i = 0; i < nr; i++) {
2669                 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2670                 btrfs_set_item_key(leaf, &disk_key, slot + i);
2671                 item = btrfs_item_nr(leaf, slot + i);
2672                 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2673                 data_end -= data_size[i];
2674                 btrfs_set_item_size(leaf, item, data_size[i]);
2675         }
2676         btrfs_set_header_nritems(leaf, nritems + nr);
2677         btrfs_mark_buffer_dirty(leaf);
2678
2679         ret = 0;
2680         if (slot == 0) {
2681                 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2682                 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2683         }
2684
2685         if (btrfs_leaf_free_space(root, leaf) < 0) {
2686                 btrfs_print_leaf(root, leaf);
2687                 BUG();
2688         }
2689 out:
2690         return ret;
2691 }
2692
2693 /*
2694  * Given a key and some data, insert an item into the tree.
2695  * This does all the path init required, making room in the tree if needed.
2696  */
2697 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2698                       *root, struct btrfs_key *cpu_key, void *data, u32
2699                       data_size)
2700 {
2701         int ret = 0;
2702         struct btrfs_path *path;
2703         struct extent_buffer *leaf;
2704         unsigned long ptr;
2705
2706         path = btrfs_alloc_path();
2707         BUG_ON(!path);
2708         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2709         if (!ret) {
2710                 leaf = path->nodes[0];
2711                 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2712                 write_extent_buffer(leaf, data, ptr, data_size);
2713                 btrfs_mark_buffer_dirty(leaf);
2714         }
2715         btrfs_free_path(path);
2716         return ret;
2717 }
2718
2719 /*
2720  * delete the pointer from a given node.
2721  *
2722  * If the delete empties a node, the node is removed from the tree,
2723  * continuing all the way the root if required.  The root is converted into
2724  * a leaf if all the nodes are emptied.
2725  */
2726 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2727                    struct btrfs_path *path, int level, int slot)
2728 {
2729         struct extent_buffer *parent = path->nodes[level];
2730         u32 nritems;
2731         int ret = 0;
2732         int wret;
2733
2734         nritems = btrfs_header_nritems(parent);
2735         if (slot != nritems -1) {
2736                 memmove_extent_buffer(parent,
2737                               btrfs_node_key_ptr_offset(slot),
2738                               btrfs_node_key_ptr_offset(slot + 1),
2739                               sizeof(struct btrfs_key_ptr) *
2740                               (nritems - slot - 1));
2741         }
2742         nritems--;
2743         btrfs_set_header_nritems(parent, nritems);
2744         if (nritems == 0 && parent == root->node) {
2745                 BUG_ON(btrfs_header_level(root->node) != 1);
2746                 /* just turn the root into a leaf and break */
2747                 btrfs_set_header_level(root->node, 0);
2748         } else if (slot == 0) {
2749                 struct btrfs_disk_key disk_key;
2750
2751                 btrfs_node_key(parent, &disk_key, 0);
2752                 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2753                 if (wret)
2754                         ret = wret;
2755         }
2756         btrfs_mark_buffer_dirty(parent);
2757         return ret;
2758 }
2759
2760 /*
2761  * delete the item at the leaf level in path.  If that empties
2762  * the leaf, remove it from the tree
2763  */
2764 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2765                     struct btrfs_path *path, int slot, int nr)
2766 {
2767         struct extent_buffer *leaf;
2768         struct btrfs_item *item;
2769         int last_off;
2770         int dsize = 0;
2771         int ret = 0;
2772         int wret;
2773         int i;
2774         u32 nritems;
2775
2776         leaf = path->nodes[0];
2777         last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2778
2779         for (i = 0; i < nr; i++)
2780                 dsize += btrfs_item_size_nr(leaf, slot + i);
2781
2782         nritems = btrfs_header_nritems(leaf);
2783
2784         if (slot + nr != nritems) {
2785                 int i;
2786                 int data_end = leaf_data_end(root, leaf);
2787
2788                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2789                               data_end + dsize,
2790                               btrfs_leaf_data(leaf) + data_end,
2791                               last_off - data_end);
2792
2793                 for (i = slot + nr; i < nritems; i++) {
2794                         u32 ioff;
2795
2796                         item = btrfs_item_nr(leaf, i);
2797                         if (!leaf->map_token) {
2798                                 map_extent_buffer(leaf, (unsigned long)item,
2799                                         sizeof(struct btrfs_item),
2800                                         &leaf->map_token, &leaf->kaddr,
2801                                         &leaf->map_start, &leaf->map_len,
2802                                         KM_USER1);
2803                         }
2804                         ioff = btrfs_item_offset(leaf, item);
2805                         btrfs_set_item_offset(leaf, item, ioff + dsize);
2806                 }
2807
2808                 if (leaf->map_token) {
2809                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2810                         leaf->map_token = NULL;
2811                 }
2812
2813                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2814                               btrfs_item_nr_offset(slot + nr),
2815                               sizeof(struct btrfs_item) *
2816                               (nritems - slot - nr));
2817         }
2818         btrfs_set_header_nritems(leaf, nritems - nr);
2819         nritems -= nr;
2820
2821         /* delete the leaf if we've emptied it */
2822         if (nritems == 0) {
2823                 if (leaf == root->node) {
2824                         btrfs_set_header_level(leaf, 0);
2825                 } else {
2826                         u64 root_gen = btrfs_header_generation(path->nodes[1]);
2827                         wret = del_ptr(trans, root, path, 1, path->slots[1]);
2828                         if (wret)
2829                                 ret = wret;
2830                         wret = btrfs_free_extent(trans, root,
2831                                          leaf->start, leaf->len,
2832                                          btrfs_header_owner(path->nodes[1]),
2833                                          root_gen, 0, 0, 1);
2834                         if (wret)
2835                                 ret = wret;
2836                 }
2837         } else {
2838                 int used = leaf_space_used(leaf, 0, nritems);
2839                 if (slot == 0) {
2840                         struct btrfs_disk_key disk_key;
2841
2842                         btrfs_item_key(leaf, &disk_key, 0);
2843                         wret = fixup_low_keys(trans, root, path,
2844                                               &disk_key, 1);
2845                         if (wret)
2846                                 ret = wret;
2847                 }
2848
2849                 /* delete the leaf if it is mostly empty */
2850                 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2851                         /* push_leaf_left fixes the path.
2852                          * make sure the path still points to our leaf
2853                          * for possible call to del_ptr below
2854                          */
2855                         slot = path->slots[1];
2856                         extent_buffer_get(leaf);
2857
2858                         wret = push_leaf_left(trans, root, path, 1, 1);
2859                         if (wret < 0 && wret != -ENOSPC)
2860                                 ret = wret;
2861
2862                         if (path->nodes[0] == leaf &&
2863                             btrfs_header_nritems(leaf)) {
2864                                 wret = push_leaf_right(trans, root, path, 1, 1);
2865                                 if (wret < 0 && wret != -ENOSPC)
2866                                         ret = wret;
2867                         }
2868
2869                         if (btrfs_header_nritems(leaf) == 0) {
2870                                 u64 root_gen;
2871                                 u64 bytenr = leaf->start;
2872                                 u32 blocksize = leaf->len;
2873
2874                                 root_gen = btrfs_header_generation(
2875                                                            path->nodes[1]);
2876
2877                                 wret = del_ptr(trans, root, path, 1, slot);
2878                                 if (wret)
2879                                         ret = wret;
2880
2881                                 free_extent_buffer(leaf);
2882                                 wret = btrfs_free_extent(trans, root, bytenr,
2883                                              blocksize,
2884                                              btrfs_header_owner(path->nodes[1]),
2885                                              root_gen, 0, 0, 1);
2886                                 if (wret)
2887                                         ret = wret;
2888                         } else {
2889                                 /* if we're still in the path, make sure
2890                                  * we're dirty.  Otherwise, one of the
2891                                  * push_leaf functions must have already
2892                                  * dirtied this buffer
2893                                  */
2894                                 if (path->nodes[0] == leaf)
2895                                         btrfs_mark_buffer_dirty(leaf);
2896                                 free_extent_buffer(leaf);
2897                         }
2898                 } else {
2899                         btrfs_mark_buffer_dirty(leaf);
2900                 }
2901         }
2902         return ret;
2903 }
2904
2905 /*
2906  * search the tree again to find a leaf with lesser keys
2907  * returns 0 if it found something or 1 if there are no lesser leaves.
2908  * returns < 0 on io errors.
2909  */
2910 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2911 {
2912         struct btrfs_key key;
2913         struct btrfs_disk_key found_key;
2914         int ret;
2915
2916         btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
2917
2918         if (key.offset > 0)
2919                 key.offset--;
2920         else if (key.type > 0)
2921                 key.type--;
2922         else if (key.objectid > 0)
2923                 key.objectid--;
2924         else
2925                 return 1;
2926
2927         btrfs_release_path(root, path);
2928         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2929         if (ret < 0)
2930                 return ret;
2931         btrfs_item_key(path->nodes[0], &found_key, 0);
2932         ret = comp_keys(&found_key, &key);
2933         if (ret < 0)
2934                 return 0;
2935         return 1;
2936 }
2937
2938 /*
2939  * search the tree again to find a leaf with greater keys
2940  * returns 0 if it found something or 1 if there are no greater leaves.
2941  * returns < 0 on io errors.
2942  */
2943 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2944 {
2945         int slot;
2946         int level = 1;
2947         struct extent_buffer *c;
2948         struct extent_buffer *next = NULL;
2949         struct btrfs_key key;
2950         u32 nritems;
2951         int ret;
2952
2953         nritems = btrfs_header_nritems(path->nodes[0]);
2954         if (nritems == 0) {
2955                 return 1;
2956         }
2957
2958         btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
2959
2960         path->keep_locks = 1;
2961         btrfs_release_path(root, path);
2962         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2963         path->keep_locks = 0;
2964
2965         if (ret < 0)
2966                 return ret;
2967
2968         if (path->slots[0] < nritems - 1) {
2969                 goto done;
2970         }
2971
2972         while(level < BTRFS_MAX_LEVEL) {
2973                 if (!path->nodes[level])
2974                         return 1;
2975
2976                 slot = path->slots[level] + 1;
2977                 c = path->nodes[level];
2978                 if (slot >= btrfs_header_nritems(c)) {
2979                         level++;
2980                         if (level == BTRFS_MAX_LEVEL) {
2981                                 return 1;
2982                         }
2983                         continue;
2984                 }
2985
2986                 if (next) {
2987                         btrfs_tree_unlock(next);
2988                         free_extent_buffer(next);
2989                 }
2990
2991                 if (level == 1 && path->locks[1] && path->reada)
2992                         reada_for_search(root, path, level, slot, 0);
2993
2994                 next = read_node_slot(root, c, slot);
2995                 if (!path->skip_locking)
2996                         btrfs_tree_lock(next);
2997                 break;
2998         }
2999         path->slots[level] = slot;
3000         while(1) {
3001                 level--;
3002                 c = path->nodes[level];
3003                 if (path->locks[level])
3004                         btrfs_tree_unlock(c);
3005                 free_extent_buffer(c);
3006                 path->nodes[level] = next;
3007                 path->slots[level] = 0;
3008                 path->locks[level] = 1;
3009                 if (!level)
3010                         break;
3011                 if (level == 1 && path->locks[1] && path->reada)
3012                         reada_for_search(root, path, level, slot, 0);
3013                 next = read_node_slot(root, next, 0);
3014                 if (!path->skip_locking)
3015                         btrfs_tree_lock(next);
3016         }
3017 done:
3018         unlock_up(path, 0, 1);
3019         return 0;
3020 }
3021
3022 int btrfs_previous_item(struct btrfs_root *root,
3023                         struct btrfs_path *path, u64 min_objectid,
3024                         int type)
3025 {
3026         struct btrfs_key found_key;
3027         struct extent_buffer *leaf;
3028         int ret;
3029
3030         while(1) {
3031                 if (path->slots[0] == 0) {
3032                         ret = btrfs_prev_leaf(root, path);
3033                         if (ret != 0)
3034                                 return ret;
3035                 } else {
3036                         path->slots[0]--;
3037                 }
3038                 leaf = path->nodes[0];
3039                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3040                 if (found_key.type == type)
3041                         return 0;
3042         }
3043         return 1;
3044 }
3045