Pileus Git - ~andy/linux/blob - fs/btrfs/ctree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/sched.h>
  20 #include "ctree.h"
  21 #include "disk-io.h"
  22 #include "transaction.h"
  23 #include "print-tree.h"
  24 #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         int keep = p->keep_locks;
  67         int skip = p->skip_locking;
  68
  69         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
  70                 if (!p->nodes[i])
  71                         continue;
  72                 if (p->locks[i]) {
  73                         btrfs_tree_unlock(p->nodes[i]);
  74                         p->locks[i] = 0;
  75                 }
  76                 free_extent_buffer(p->nodes[i]);
  77         }
  78         memset(p, 0, sizeof(*p));
  79         p->keep_locks = keep;
  80         p->skip_locking = skip;
  81 }
  82
  83 struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
  84 {
  85         struct extent_buffer *eb;
  86         spin_lock(&root->node_lock);
  87         eb = root->node;
  88         extent_buffer_get(eb);
  89         spin_unlock(&root->node_lock);
  90         return eb;
  91 }
  92
  93 struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
  94 {
  95         struct extent_buffer *eb;
  96
  97         while(1) {
  98                 eb = btrfs_root_node(root);
  99                 btrfs_tree_lock(eb);
 100
 101                 spin_lock(&root->node_lock);
 102                 if (eb == root->node) {
 103                         spin_unlock(&root->node_lock);
 104                         break;
 105                 }
 106                 spin_unlock(&root->node_lock);
 107
 108                 btrfs_tree_unlock(eb);
 109                 free_extent_buffer(eb);
 110         }
 111         return eb;
 112 }
 113
 114 static void add_root_to_dirty_list(struct btrfs_root *root)
 115 {
 116         if (root->track_dirty && list_empty(&root->dirty_list)) {
 117                 list_add(&root->dirty_list,
 118                          &root->fs_info->dirty_cowonly_roots);
 119         }
 120 }
 121
 122 int btrfs_copy_root(struct btrfs_trans_handle *trans,
 123                       struct btrfs_root *root,
 124                       struct extent_buffer *buf,
 125                       struct extent_buffer **cow_ret, u64 new_root_objectid)
 126 {
 127         struct extent_buffer *cow;
 128         u32 nritems;
 129         int ret = 0;
 130         int level;
 131         struct btrfs_key first_key;
 132         struct btrfs_root *new_root;
 133
 134         new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
 135         if (!new_root)
 136                 return -ENOMEM;
 137
 138         memcpy(new_root, root, sizeof(*new_root));
 139         new_root->root_key.objectid = new_root_objectid;
 140
 141         WARN_ON(root->ref_cows && trans->transid !=
 142                 root->fs_info->running_transaction->transid);
 143         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 144
 145         level = btrfs_header_level(buf);
 146         nritems = btrfs_header_nritems(buf);
 147         if (nritems) {
 148                 if (level == 0)
 149                         btrfs_item_key_to_cpu(buf, &first_key, 0);
 150                 else
 151                         btrfs_node_key_to_cpu(buf, &first_key, 0);
 152         } else {
 153                 first_key.objectid = 0;
 154         }
 155         cow = btrfs_alloc_free_block(trans, new_root, buf->len,
 156                                        new_root_objectid,
 157                                        trans->transid, first_key.objectid,
 158                                        level, buf->start, 0);
 159         if (IS_ERR(cow)) {
 160                 kfree(new_root);
 161                 return PTR_ERR(cow);
 162         }
 163
 164         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 165         btrfs_set_header_bytenr(cow, cow->start);
 166         btrfs_set_header_generation(cow, trans->transid);
 167         btrfs_set_header_owner(cow, new_root_objectid);
 168         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 169
 170         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 171         ret = btrfs_inc_ref(trans, new_root, buf);
 172         kfree(new_root);
 173
 174         if (ret)
 175                 return ret;
 176
 177         btrfs_mark_buffer_dirty(cow);
 178         *cow_ret = cow;
 179         return 0;
 180 }
 181
 182 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 183                              struct btrfs_root *root,
 184                              struct extent_buffer *buf,
 185                              struct extent_buffer *parent, int parent_slot,
 186                              struct extent_buffer **cow_ret,
 187                              u64 search_start, u64 empty_size)
 188 {
 189         u64 root_gen;
 190         struct extent_buffer *cow;
 191         u32 nritems;
 192         int ret = 0;
 193         int different_trans = 0;
 194         int level;
 195         int unlock_orig = 0;
 196         struct btrfs_key first_key;
 197
 198         if (*cow_ret == buf)
 199                 unlock_orig = 1;
 200
 201         WARN_ON(!btrfs_tree_locked(buf));
 202
 203         if (root->ref_cows) {
 204                 root_gen = trans->transid;
 205         } else {
 206                 root_gen = 0;
 207         }
 208         WARN_ON(root->ref_cows && trans->transid !=
 209                 root->fs_info->running_transaction->transid);
 210         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 211
 212         level = btrfs_header_level(buf);
 213         nritems = btrfs_header_nritems(buf);
 214         if (nritems) {
 215                 if (level == 0)
 216                         btrfs_item_key_to_cpu(buf, &first_key, 0);
 217                 else
 218                         btrfs_node_key_to_cpu(buf, &first_key, 0);
 219         } else {
 220                 first_key.objectid = 0;
 221         }
 222         cow = btrfs_alloc_free_block(trans, root, buf->len,
 223                                      root->root_key.objectid,
 224                                      root_gen, first_key.objectid, level,
 225                                      search_start, empty_size);
 226         if (IS_ERR(cow))
 227                 return PTR_ERR(cow);
 228
 229         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 230         btrfs_set_header_bytenr(cow, cow->start);
 231         btrfs_set_header_generation(cow, trans->transid);
 232         btrfs_set_header_owner(cow, root->root_key.objectid);
 233         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 234
 235         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 236         if (btrfs_header_generation(buf) != trans->transid) {
 237                 different_trans = 1;
 238                 ret = btrfs_inc_ref(trans, root, buf);
 239                 if (ret)
 240                         return ret;
 241         } else {
 242                 clean_tree_block(trans, root, buf);
 243         }
 244
 245         if (buf == root->node) {
 246                 WARN_ON(parent && parent != buf);
 247                 root_gen = btrfs_header_generation(buf);
 248
 249                 spin_lock(&root->node_lock);
 250                 root->node = cow;
 251                 extent_buffer_get(cow);
 252                 spin_unlock(&root->node_lock);
 253
 254                 if (buf != root->commit_root) {
 255                         btrfs_free_extent(trans, root, buf->start,
 256                                           buf->len, root->root_key.objectid,
 257                                           root_gen, 0, 0, 1);
 258                 }
 259                 free_extent_buffer(buf);
 260                 add_root_to_dirty_list(root);
 261         } else {
 262                 root_gen = btrfs_header_generation(parent);
 263                 btrfs_set_node_blockptr(parent, parent_slot,
 264                                         cow->start);
 265                 WARN_ON(trans->transid == 0);
 266                 btrfs_set_node_ptr_generation(parent, parent_slot,
 267                                               trans->transid);
 268                 btrfs_mark_buffer_dirty(parent);
 269                 WARN_ON(btrfs_header_generation(parent) != trans->transid);
 270                 btrfs_free_extent(trans, root, buf->start, buf->len,
 271                                   btrfs_header_owner(parent), root_gen,
 272                                   0, 0, 1);
 273         }
 274         if (unlock_orig)
 275                 btrfs_tree_unlock(buf);
 276         free_extent_buffer(buf);
 277         btrfs_mark_buffer_dirty(cow);
 278         *cow_ret = cow;
 279         return 0;
 280 }
 281
 282 int btrfs_cow_block(struct btrfs_trans_handle *trans,
 283                     struct btrfs_root *root, struct extent_buffer *buf,
 284                     struct extent_buffer *parent, int parent_slot,
 285                     struct extent_buffer **cow_ret)
 286 {
 287         u64 search_start;
 288         u64 header_trans;
 289         int ret;
 290
 291         if (trans->transaction != root->fs_info->running_transaction) {
 292                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 293                        root->fs_info->running_transaction->transid);
 294                 WARN_ON(1);
 295         }
 296         if (trans->transid != root->fs_info->generation) {
 297                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 298                        root->fs_info->generation);
 299                 WARN_ON(1);
 300         }
 301
 302         header_trans = btrfs_header_generation(buf);
 303         spin_lock(&root->fs_info->hash_lock);
 304         if (header_trans == trans->transid &&
 305             !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
 306                 *cow_ret = buf;
 307                 spin_unlock(&root->fs_info->hash_lock);
 308                 return 0;
 309         }
 310         spin_unlock(&root->fs_info->hash_lock);
 311         search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
 312         ret = __btrfs_cow_block(trans, root, buf, parent,
 313                                  parent_slot, cow_ret, search_start, 0);
 314         return ret;
 315 }
 316
 317 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
 318 {
 319         if (blocknr < other && other - (blocknr + blocksize) < 32768)
 320                 return 1;
 321         if (blocknr > other && blocknr - (other + blocksize) < 32768)
 322                 return 1;
 323         return 0;
 324 }
 325
 326 /*
 327  * compare two keys in a memcmp fashion
 328  */
 329 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
 330 {
 331         struct btrfs_key k1;
 332
 333         btrfs_disk_key_to_cpu(&k1, disk);
 334
 335         if (k1.objectid > k2->objectid)
 336                 return 1;
 337         if (k1.objectid < k2->objectid)
 338                 return -1;
 339         if (k1.type > k2->type)
 340                 return 1;
 341         if (k1.type < k2->type)
 342                 return -1;
 343         if (k1.offset > k2->offset)
 344                 return 1;
 345         if (k1.offset < k2->offset)
 346                 return -1;
 347         return 0;
 348 }
 349
 350
 351 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 352                        struct btrfs_root *root, struct extent_buffer *parent,
 353                        int start_slot, int cache_only, u64 *last_ret,
 354                        struct btrfs_key *progress)
 355 {
 356         struct extent_buffer *cur;
 357         u64 blocknr;
 358         u64 gen;
 359         u64 search_start = *last_ret;
 360         u64 last_block = 0;
 361         u64 other;
 362         u32 parent_nritems;
 363         int end_slot;
 364         int i;
 365         int err = 0;
 366         int parent_level;
 367         int uptodate;
 368         u32 blocksize;
 369         int progress_passed = 0;
 370         struct btrfs_disk_key disk_key;
 371
 372         parent_level = btrfs_header_level(parent);
 373         if (cache_only && parent_level != 1)
 374                 return 0;
 375
 376         if (trans->transaction != root->fs_info->running_transaction) {
 377                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 378                        root->fs_info->running_transaction->transid);
 379                 WARN_ON(1);
 380         }
 381         if (trans->transid != root->fs_info->generation) {
 382                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 383                        root->fs_info->generation);
 384                 WARN_ON(1);
 385         }
 386
 387         parent_nritems = btrfs_header_nritems(parent);
 388         blocksize = btrfs_level_size(root, parent_level - 1);
 389         end_slot = parent_nritems;
 390
 391         if (parent_nritems == 1)
 392                 return 0;
 393
 394         for (i = start_slot; i < end_slot; i++) {
 395                 int close = 1;
 396
 397                 if (!parent->map_token) {
 398                         map_extent_buffer(parent,
 399                                         btrfs_node_key_ptr_offset(i),
 400                                         sizeof(struct btrfs_key_ptr),
 401                                         &parent->map_token, &parent->kaddr,
 402                                         &parent->map_start, &parent->map_len,
 403                                         KM_USER1);
 404                 }
 405                 btrfs_node_key(parent, &disk_key, i);
 406                 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
 407                         continue;
 408
 409                 progress_passed = 1;
 410                 blocknr = btrfs_node_blockptr(parent, i);
 411                 gen = btrfs_node_ptr_generation(parent, i);
 412                 if (last_block == 0)
 413                         last_block = blocknr;
 414
 415                 if (i > 0) {
 416                         other = btrfs_node_blockptr(parent, i - 1);
 417                         close = close_blocks(blocknr, other, blocksize);
 418                 }
 419                 if (!close && i < end_slot - 2) {
 420                         other = btrfs_node_blockptr(parent, i + 1);
 421                         close = close_blocks(blocknr, other, blocksize);
 422                 }
 423                 if (close) {
 424                         last_block = blocknr;
 425                         continue;
 426                 }
 427                 if (parent->map_token) {
 428                         unmap_extent_buffer(parent, parent->map_token,
 429                                             KM_USER1);
 430                         parent->map_token = NULL;
 431                 }
 432
 433                 cur = btrfs_find_tree_block(root, blocknr, blocksize);
 434                 if (cur)
 435                         uptodate = btrfs_buffer_uptodate(cur, gen);
 436                 else
 437                         uptodate = 0;
 438                 if (!cur || !uptodate) {
 439                         if (cache_only) {
 440                                 free_extent_buffer(cur);
 441                                 continue;
 442                         }
 443                         if (!cur) {
 444                                 cur = read_tree_block(root, blocknr,
 445                                                          blocksize, gen);
 446                         } else if (!uptodate) {
 447                                 btrfs_read_buffer(cur, gen);
 448                         }
 449                 }
 450                 if (search_start == 0)
 451                         search_start = last_block;
 452
 453                 btrfs_tree_lock(cur);
 454                 err = __btrfs_cow_block(trans, root, cur, parent, i,
 455                                         &cur, search_start,
 456                                         min(16 * blocksize,
 457                                             (end_slot - i) * blocksize));
 458                 if (err) {
 459                         btrfs_tree_unlock(cur);
 460                         free_extent_buffer(cur);
 461                         break;
 462                 }
 463                 search_start = cur->start;
 464                 last_block = cur->start;
 465                 *last_ret = search_start;
 466                 if (parent_level == 1)
 467                         btrfs_clear_buffer_defrag(cur);
 468                 btrfs_tree_unlock(cur);
 469                 free_extent_buffer(cur);
 470         }
 471         if (parent->map_token) {
 472                 unmap_extent_buffer(parent, parent->map_token,
 473                                     KM_USER1);
 474                 parent->map_token = NULL;
 475         }
 476         return err;
 477 }
 478
 479 /*
 480  * The leaf data grows from end-to-front in the node.
 481  * this returns the address of the start of the last item,
 482  * which is the stop of the leaf data stack
 483  */
 484 static inline unsigned int leaf_data_end(struct btrfs_root *root,
 485                                          struct extent_buffer *leaf)
 486 {
 487         u32 nr = btrfs_header_nritems(leaf);
 488         if (nr == 0)
 489                 return BTRFS_LEAF_DATA_SIZE(root);
 490         return btrfs_item_offset_nr(leaf, nr - 1);
 491 }
 492
 493 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
 494                       int level)
 495 {
 496         struct extent_buffer *parent = NULL;
 497         struct extent_buffer *node = path->nodes[level];
 498         struct btrfs_disk_key parent_key;
 499         struct btrfs_disk_key node_key;
 500         int parent_slot;
 501         int slot;
 502         struct btrfs_key cpukey;
 503         u32 nritems = btrfs_header_nritems(node);
 504
 505         if (path->nodes[level + 1])
 506                 parent = path->nodes[level + 1];
 507
 508         slot = path->slots[level];
 509         BUG_ON(nritems == 0);
 510         if (parent) {
 511                 parent_slot = path->slots[level + 1];
 512                 btrfs_node_key(parent, &parent_key, parent_slot);
 513                 btrfs_node_key(node, &node_key, 0);
 514                 BUG_ON(memcmp(&parent_key, &node_key,
 515                               sizeof(struct btrfs_disk_key)));
 516                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 517                        btrfs_header_bytenr(node));
 518         }
 519         BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
 520         if (slot != 0) {
 521                 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
 522                 btrfs_node_key(node, &node_key, slot);
 523                 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
 524         }
 525         if (slot < nritems - 1) {
 526                 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
 527                 btrfs_node_key(node, &node_key, slot);
 528                 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
 529         }
 530         return 0;
 531 }
 532
 533 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
 534                       int level)
 535 {
 536         struct extent_buffer *leaf = path->nodes[level];
 537         struct extent_buffer *parent = NULL;
 538         int parent_slot;
 539         struct btrfs_key cpukey;
 540         struct btrfs_disk_key parent_key;
 541         struct btrfs_disk_key leaf_key;
 542         int slot = path->slots[0];
 543
 544         u32 nritems = btrfs_header_nritems(leaf);
 545
 546         if (path->nodes[level + 1])
 547                 parent = path->nodes[level + 1];
 548
 549         if (nritems == 0)
 550                 return 0;
 551
 552         if (parent) {
 553                 parent_slot = path->slots[level + 1];
 554                 btrfs_node_key(parent, &parent_key, parent_slot);
 555                 btrfs_item_key(leaf, &leaf_key, 0);
 556
 557                 BUG_ON(memcmp(&parent_key, &leaf_key,
 558                        sizeof(struct btrfs_disk_key)));
 559                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 560                        btrfs_header_bytenr(leaf));
 561         }
 562 #if 0
 563         for (i = 0; nritems > 1 && i < nritems - 2; i++) {
 564                 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
 565                 btrfs_item_key(leaf, &leaf_key, i);
 566                 if (comp_keys(&leaf_key, &cpukey) >= 0) {
 567                         btrfs_print_leaf(root, leaf);
 568                         printk("slot %d offset bad key\n", i);
 569                         BUG_ON(1);
 570                 }
 571                 if (btrfs_item_offset_nr(leaf, i) !=
 572                         btrfs_item_end_nr(leaf, i + 1)) {
 573                         btrfs_print_leaf(root, leaf);
 574                         printk("slot %d offset bad\n", i);
 575                         BUG_ON(1);
 576                 }
 577                 if (i == 0) {
 578                         if (btrfs_item_offset_nr(leaf, i) +
 579                                btrfs_item_size_nr(leaf, i) !=
 580                                BTRFS_LEAF_DATA_SIZE(root)) {
 581                                 btrfs_print_leaf(root, leaf);
 582                                 printk("slot %d first offset bad\n", i);
 583                                 BUG_ON(1);
 584                         }
 585                 }
 586         }
 587         if (nritems > 0) {
 588                 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
 589                                 btrfs_print_leaf(root, leaf);
 590                                 printk("slot %d bad size \n", nritems - 1);
 591                                 BUG_ON(1);
 592                 }
 593         }
 594 #endif
 595         if (slot != 0 && slot < nritems - 1) {
 596                 btrfs_item_key(leaf, &leaf_key, slot);
 597                 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
 598                 if (comp_keys(&leaf_key, &cpukey) <= 0) {
 599                         btrfs_print_leaf(root, leaf);
 600                         printk("slot %d offset bad key\n", slot);
 601                         BUG_ON(1);
 602                 }
 603                 if (btrfs_item_offset_nr(leaf, slot - 1) !=
 604                        btrfs_item_end_nr(leaf, slot)) {
 605                         btrfs_print_leaf(root, leaf);
 606                         printk("slot %d offset bad\n", slot);
 607                         BUG_ON(1);
 608                 }
 609         }
 610         if (slot < nritems - 1) {
 611                 btrfs_item_key(leaf, &leaf_key, slot);
 612                 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
 613                 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
 614                 if (btrfs_item_offset_nr(leaf, slot) !=
 615                         btrfs_item_end_nr(leaf, slot + 1)) {
 616                         btrfs_print_leaf(root, leaf);
 617                         printk("slot %d offset bad\n", slot);
 618                         BUG_ON(1);
 619                 }
 620         }
 621         BUG_ON(btrfs_item_offset_nr(leaf, 0) +
 622                btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
 623         return 0;
 624 }
 625
 626 static int noinline check_block(struct btrfs_root *root,
 627                                 struct btrfs_path *path, int level)
 628 {
 629         u64 found_start;
 630         return 0;
 631         if (btrfs_header_level(path->nodes[level]) != level)
 632             printk("warning: bad level %Lu wanted %d found %d\n",
 633                    path->nodes[level]->start, level,
 634                    btrfs_header_level(path->nodes[level]));
 635         found_start = btrfs_header_bytenr(path->nodes[level]);
 636         if (found_start != path->nodes[level]->start) {
 637             printk("warning: bad bytentr %Lu found %Lu\n",
 638                    path->nodes[level]->start, found_start);
 639         }
 640 #if 0
 641         struct extent_buffer *buf = path->nodes[level];
 642
 643         if (memcmp_extent_buffer(buf, root->fs_info->fsid,
 644                                  (unsigned long)btrfs_header_fsid(buf),
 645                                  BTRFS_FSID_SIZE)) {
 646                 printk("warning bad block %Lu\n", buf->start);
 647                 return 1;
 648         }
 649 #endif
 650         if (level == 0)
 651                 return check_leaf(root, path, level);
 652         return check_node(root, path, level);
 653 }
 654
 655 /*
 656  * search for key in the extent_buffer.  The items start at offset p,
 657  * and they are item_size apart.  There are 'max' items in p.
 658  *
 659  * the slot in the array is returned via slot, and it points to
 660  * the place where you would insert key if it is not found in
 661  * the array.
 662  *
 663  * slot may point to max if the key is bigger than all of the keys
 664  */
 665 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
 666                               int item_size, struct btrfs_key *key,
 667                               int max, int *slot)
 668 {
 669         int low = 0;
 670         int high = max;
 671         int mid;
 672         int ret;
 673         struct btrfs_disk_key *tmp = NULL;
 674         struct btrfs_disk_key unaligned;
 675         unsigned long offset;
 676         char *map_token = NULL;
 677         char *kaddr = NULL;
 678         unsigned long map_start = 0;
 679         unsigned long map_len = 0;
 680         int err;
 681
 682         while(low < high) {
 683                 mid = (low + high) / 2;
 684                 offset = p + mid * item_size;
 685
 686                 if (!map_token || offset < map_start ||
 687                     (offset + sizeof(struct btrfs_disk_key)) >
 688                     map_start + map_len) {
 689                         if (map_token) {
 690                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 691                                 map_token = NULL;
 692                         }
 693                         err = map_extent_buffer(eb, offset,
 694                                                 sizeof(struct btrfs_disk_key),
 695                                                 &map_token, &kaddr,
 696                                                 &map_start, &map_len, KM_USER0);
 697
 698                         if (!err) {
 699                                 tmp = (struct btrfs_disk_key *)(kaddr + offset -
 700                                                         map_start);
 701                         } else {
 702                                 read_extent_buffer(eb, &unaligned,
 703                                                    offset, sizeof(unaligned));
 704                                 tmp = &unaligned;
 705                         }
 706
 707                 } else {
 708                         tmp = (struct btrfs_disk_key *)(kaddr + offset -
 709                                                         map_start);
 710                 }
 711                 ret = comp_keys(tmp, key);
 712
 713                 if (ret < 0)
 714                         low = mid + 1;
 715                 else if (ret > 0)
 716                         high = mid;
 717                 else {
 718                         *slot = mid;
 719                         if (map_token)
 720                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 721                         return 0;
 722                 }
 723         }
 724         *slot = low;
 725         if (map_token)
 726                 unmap_extent_buffer(eb, map_token, KM_USER0);
 727         return 1;
 728 }
 729
 730 /*
 731  * simple bin_search frontend that does the right thing for
 732  * leaves vs nodes
 733  */
 734 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
 735                       int level, int *slot)
 736 {
 737         if (level == 0) {
 738                 return generic_bin_search(eb,
 739                                           offsetof(struct btrfs_leaf, items),
 740                                           sizeof(struct btrfs_item),
 741                                           key, btrfs_header_nritems(eb),
 742                                           slot);
 743         } else {
 744                 return generic_bin_search(eb,
 745                                           offsetof(struct btrfs_node, ptrs),
 746                                           sizeof(struct btrfs_key_ptr),
 747                                           key, btrfs_header_nritems(eb),
 748                                           slot);
 749         }
 750         return -1;
 751 }
 752
 753 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
 754                                    struct extent_buffer *parent, int slot)
 755 {
 756         int level = btrfs_header_level(parent);
 757         if (slot < 0)
 758                 return NULL;
 759         if (slot >= btrfs_header_nritems(parent))
 760                 return NULL;
 761
 762         BUG_ON(level == 0);
 763
 764         return read_tree_block(root, btrfs_node_blockptr(parent, slot),
 765                        btrfs_level_size(root, level - 1),
 766                        btrfs_node_ptr_generation(parent, slot));
 767 }
 768
 769 static int balance_level(struct btrfs_trans_handle *trans,
 770                          struct btrfs_root *root,
 771                          struct btrfs_path *path, int level)
 772 {
 773         struct extent_buffer *right = NULL;
 774         struct extent_buffer *mid;
 775         struct extent_buffer *left = NULL;
 776         struct extent_buffer *parent = NULL;
 777         int ret = 0;
 778         int wret;
 779         int pslot;
 780         int orig_slot = path->slots[level];
 781         int err_on_enospc = 0;
 782         u64 orig_ptr;
 783
 784         if (level == 0)
 785                 return 0;
 786
 787         mid = path->nodes[level];
 788         WARN_ON(!path->locks[level]);
 789         WARN_ON(btrfs_header_generation(mid) != trans->transid);
 790
 791         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 792
 793         if (level < BTRFS_MAX_LEVEL - 1)
 794                 parent = path->nodes[level + 1];
 795         pslot = path->slots[level + 1];
 796
 797         /*
 798          * deal with the case where there is only one pointer in the root
 799          * by promoting the node below to a root
 800          */
 801         if (!parent) {
 802                 struct extent_buffer *child;
 803
 804                 if (btrfs_header_nritems(mid) != 1)
 805                         return 0;
 806
 807                 /* promote the child to a root */
 808                 child = read_node_slot(root, mid, 0);
 809                 btrfs_tree_lock(child);
 810                 BUG_ON(!child);
 811                 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
 812                 BUG_ON(ret);
 813
 814                 spin_lock(&root->node_lock);
 815                 root->node = child;
 816                 spin_unlock(&root->node_lock);
 817
 818                 add_root_to_dirty_list(root);
 819                 btrfs_tree_unlock(child);
 820                 path->locks[level] = 0;
 821                 path->nodes[level] = NULL;
 822                 clean_tree_block(trans, root, mid);
 823                 btrfs_tree_unlock(mid);
 824                 /* once for the path */
 825                 free_extent_buffer(mid);
 826                 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
 827                                         root->root_key.objectid,
 828                                         btrfs_header_generation(mid), 0, 0, 1);
 829                 /* once for the root ptr */
 830                 free_extent_buffer(mid);
 831                 return ret;
 832         }
 833         if (btrfs_header_nritems(mid) >
 834             BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
 835                 return 0;
 836
 837         if (btrfs_header_nritems(mid) < 2)
 838                 err_on_enospc = 1;
 839
 840         left = read_node_slot(root, parent, pslot - 1);
 841         if (left) {
 842                 btrfs_tree_lock(left);
 843                 wret = btrfs_cow_block(trans, root, left,
 844                                        parent, pslot - 1, &left);
 845                 if (wret) {
 846                         ret = wret;
 847                         goto enospc;
 848                 }
 849         }
 850         right = read_node_slot(root, parent, pslot + 1);
 851         if (right) {
 852                 btrfs_tree_lock(right);
 853                 wret = btrfs_cow_block(trans, root, right,
 854                                        parent, pslot + 1, &right);
 855                 if (wret) {
 856                         ret = wret;
 857                         goto enospc;
 858                 }
 859         }
 860
 861         /* first, try to make some room in the middle buffer */
 862         if (left) {
 863                 orig_slot += btrfs_header_nritems(left);
 864                 wret = push_node_left(trans, root, left, mid, 1);
 865                 if (wret < 0)
 866                         ret = wret;
 867                 if (btrfs_header_nritems(mid) < 2)
 868                         err_on_enospc = 1;
 869         }
 870
 871         /*
 872          * then try to empty the right most buffer into the middle
 873          */
 874         if (right) {
 875                 wret = push_node_left(trans, root, mid, right, 1);
 876                 if (wret < 0 && wret != -ENOSPC)
 877                         ret = wret;
 878                 if (btrfs_header_nritems(right) == 0) {
 879                         u64 bytenr = right->start;
 880                         u64 generation = btrfs_header_generation(parent);
 881                         u32 blocksize = right->len;
 882
 883                         clean_tree_block(trans, root, right);
 884                         btrfs_tree_unlock(right);
 885                         free_extent_buffer(right);
 886                         right = NULL;
 887                         wret = del_ptr(trans, root, path, level + 1, pslot +
 888                                        1);
 889                         if (wret)
 890                                 ret = wret;
 891                         wret = btrfs_free_extent(trans, root, bytenr,
 892                                                  blocksize,
 893                                                  btrfs_header_owner(parent),
 894                                                  generation, 0, 0, 1);
 895                         if (wret)
 896                                 ret = wret;
 897                 } else {
 898                         struct btrfs_disk_key right_key;
 899                         btrfs_node_key(right, &right_key, 0);
 900                         btrfs_set_node_key(parent, &right_key, pslot + 1);
 901                         btrfs_mark_buffer_dirty(parent);
 902                 }
 903         }
 904         if (btrfs_header_nritems(mid) == 1) {
 905                 /*
 906                  * we're not allowed to leave a node with one item in the
 907                  * tree during a delete.  A deletion from lower in the tree
 908                  * could try to delete the only pointer in this node.
 909                  * So, pull some keys from the left.
 910                  * There has to be a left pointer at this point because
 911                  * otherwise we would have pulled some pointers from the
 912                  * right
 913                  */
 914                 BUG_ON(!left);
 915                 wret = balance_node_right(trans, root, mid, left);
 916                 if (wret < 0) {
 917                         ret = wret;
 918                         goto enospc;
 919                 }
 920                 if (wret == 1) {
 921                         wret = push_node_left(trans, root, left, mid, 1);
 922                         if (wret < 0)
 923                                 ret = wret;
 924                 }
 925                 BUG_ON(wret == 1);
 926         }
 927         if (btrfs_header_nritems(mid) == 0) {
 928                 /* we've managed to empty the middle node, drop it */
 929                 u64 root_gen = btrfs_header_generation(parent);
 930                 u64 bytenr = mid->start;
 931                 u32 blocksize = mid->len;
 932
 933                 clean_tree_block(trans, root, mid);
 934                 btrfs_tree_unlock(mid);
 935                 free_extent_buffer(mid);
 936                 mid = NULL;
 937                 wret = del_ptr(trans, root, path, level + 1, pslot);
 938                 if (wret)
 939                         ret = wret;
 940                 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
 941                                          btrfs_header_owner(parent),
 942                                          root_gen, 0, 0, 1);
 943                 if (wret)
 944                         ret = wret;
 945         } else {
 946                 /* update the parent key to reflect our changes */
 947                 struct btrfs_disk_key mid_key;
 948                 btrfs_node_key(mid, &mid_key, 0);
 949                 btrfs_set_node_key(parent, &mid_key, pslot);
 950                 btrfs_mark_buffer_dirty(parent);
 951         }
 952
 953         /* update the path */
 954         if (left) {
 955                 if (btrfs_header_nritems(left) > orig_slot) {
 956                         extent_buffer_get(left);
 957                         /* left was locked after cow */
 958                         path->nodes[level] = left;
 959                         path->slots[level + 1] -= 1;
 960                         path->slots[level] = orig_slot;
 961                         if (mid) {
 962                                 btrfs_tree_unlock(mid);
 963                                 free_extent_buffer(mid);
 964                         }
 965                 } else {
 966                         orig_slot -= btrfs_header_nritems(left);
 967                         path->slots[level] = orig_slot;
 968                 }
 969         }
 970         /* double check we haven't messed things up */
 971         check_block(root, path, level);
 972         if (orig_ptr !=
 973             btrfs_node_blockptr(path->nodes[level], path->slots[level]))
 974                 BUG();
 975 enospc:
 976         if (right) {
 977                 btrfs_tree_unlock(right);
 978                 free_extent_buffer(right);
 979         }
 980         if (left) {
 981                 if (path->nodes[level] != left)
 982                         btrfs_tree_unlock(left);
 983                 free_extent_buffer(left);
 984         }
 985         return ret;
 986 }
 987
 988 /* returns zero if the push worked, non-zero otherwise */
 989 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
 990                                           struct btrfs_root *root,
 991                                           struct btrfs_path *path, int level)
 992 {
 993         struct extent_buffer *right = NULL;
 994         struct extent_buffer *mid;
 995         struct extent_buffer *left = NULL;
 996         struct extent_buffer *parent = NULL;
 997         int ret = 0;
 998         int wret;
 999         int pslot;
1000         int orig_slot = path->slots[level];
1001         u64 orig_ptr;
1002
1003         if (level == 0)
1004                 return 1;
1005
1006         mid = path->nodes[level];
1007         WARN_ON(btrfs_header_generation(mid) != trans->transid);
1008         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
1009
1010         if (level < BTRFS_MAX_LEVEL - 1)
1011                 parent = path->nodes[level + 1];
1012         pslot = path->slots[level + 1];
1013
1014         if (!parent)
1015                 return 1;
1016
1017         left = read_node_slot(root, parent, pslot - 1);
1018
1019         /* first, try to make some room in the middle buffer */
1020         if (left) {
1021                 u32 left_nr;
1022
1023                 btrfs_tree_lock(left);
1024                 left_nr = btrfs_header_nritems(left);
1025                 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1026                         wret = 1;
1027                 } else {
1028                         ret = btrfs_cow_block(trans, root, left, parent,
1029                                               pslot - 1, &left);
1030                         if (ret)
1031                                 wret = 1;
1032                         else {
1033                                 wret = push_node_left(trans, root,
1034                                                       left, mid, 0);
1035                         }
1036                 }
1037                 if (wret < 0)
1038                         ret = wret;
1039                 if (wret == 0) {
1040                         struct btrfs_disk_key disk_key;
1041                         orig_slot += left_nr;
1042                         btrfs_node_key(mid, &disk_key, 0);
1043                         btrfs_set_node_key(parent, &disk_key, pslot);
1044                         btrfs_mark_buffer_dirty(parent);
1045                         if (btrfs_header_nritems(left) > orig_slot) {
1046                                 path->nodes[level] = left;
1047                                 path->slots[level + 1] -= 1;
1048                                 path->slots[level] = orig_slot;
1049                                 btrfs_tree_unlock(mid);
1050                                 free_extent_buffer(mid);
1051                         } else {
1052                                 orig_slot -=
1053                                         btrfs_header_nritems(left);
1054                                 path->slots[level] = orig_slot;
1055                                 btrfs_tree_unlock(left);
1056                                 free_extent_buffer(left);
1057                         }
1058                         return 0;
1059                 }
1060                 btrfs_tree_unlock(left);
1061                 free_extent_buffer(left);
1062         }
1063         right = read_node_slot(root, parent, pslot + 1);
1064
1065         /*
1066          * then try to empty the right most buffer into the middle
1067          */
1068         if (right) {
1069                 u32 right_nr;
1070                 btrfs_tree_lock(right);
1071                 right_nr = btrfs_header_nritems(right);
1072                 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1073                         wret = 1;
1074                 } else {
1075                         ret = btrfs_cow_block(trans, root, right,
1076                                               parent, pslot + 1,
1077                                               &right);
1078                         if (ret)
1079                                 wret = 1;
1080                         else {
1081                                 wret = balance_node_right(trans, root,
1082                                                           right, mid);
1083                         }
1084                 }
1085                 if (wret < 0)
1086                         ret = wret;
1087                 if (wret == 0) {
1088                         struct btrfs_disk_key disk_key;
1089
1090                         btrfs_node_key(right, &disk_key, 0);
1091                         btrfs_set_node_key(parent, &disk_key, pslot + 1);
1092                         btrfs_mark_buffer_dirty(parent);
1093
1094                         if (btrfs_header_nritems(mid) <= orig_slot) {
1095                                 path->nodes[level] = right;
1096                                 path->slots[level + 1] += 1;
1097                                 path->slots[level] = orig_slot -
1098                                         btrfs_header_nritems(mid);
1099                                 btrfs_tree_unlock(mid);
1100                                 free_extent_buffer(mid);
1101                         } else {
1102                                 btrfs_tree_unlock(right);
1103                                 free_extent_buffer(right);
1104                         }
1105                         return 0;
1106                 }
1107                 btrfs_tree_unlock(right);
1108                 free_extent_buffer(right);
1109         }
1110         return 1;
1111 }
1112
1113 /*
1114  * readahead one full node of leaves
1115  */
1116 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
1117                              int level, int slot, u64 objectid)
1118 {
1119         struct extent_buffer *node;
1120         struct btrfs_disk_key disk_key;
1121         u32 nritems;
1122         u64 search;
1123         u64 lowest_read;
1124         u64 highest_read;
1125         u64 nread = 0;
1126         int direction = path->reada;
1127         struct extent_buffer *eb;
1128         u32 nr;
1129         u32 blocksize;
1130         u32 nscan = 0;
1131
1132         if (level != 1)
1133                 return;
1134
1135         if (!path->nodes[level])
1136                 return;
1137
1138         node = path->nodes[level];
1139
1140         search = btrfs_node_blockptr(node, slot);
1141         blocksize = btrfs_level_size(root, level - 1);
1142         eb = btrfs_find_tree_block(root, search, blocksize);
1143         if (eb) {
1144                 free_extent_buffer(eb);
1145                 return;
1146         }
1147
1148         highest_read = search;
1149         lowest_read = search;
1150
1151         nritems = btrfs_header_nritems(node);
1152         nr = slot;
1153         while(1) {
1154                 if (direction < 0) {
1155                         if (nr == 0)
1156                                 break;
1157                         nr--;
1158                 } else if (direction > 0) {
1159                         nr++;
1160                         if (nr >= nritems)
1161                                 break;
1162                 }
1163                 if (path->reada < 0 && objectid) {
1164                         btrfs_node_key(node, &disk_key, nr);
1165                         if (btrfs_disk_key_objectid(&disk_key) != objectid)
1166                                 break;
1167                 }
1168                 search = btrfs_node_blockptr(node, nr);
1169                 if ((search >= lowest_read && search <= highest_read) ||
1170                     (search < lowest_read && lowest_read - search <= 32768) ||
1171                     (search > highest_read && search - highest_read <= 32768)) {
1172                         readahead_tree_block(root, search, blocksize,
1173                                      btrfs_node_ptr_generation(node, nr));
1174                         nread += blocksize;
1175                 }
1176                 nscan++;
1177                 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1178                         break;
1179                 if(nread > (1024 * 1024) || nscan > 128)
1180                         break;
1181
1182                 if (search < lowest_read)
1183                         lowest_read = search;
1184                 if (search > highest_read)
1185                         highest_read = search;
1186         }
1187 }
1188
1189 static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
1190 {
1191         int i;
1192         int skip_level = level;
1193         int no_skips = 0;
1194         struct extent_buffer *t;
1195
1196         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1197                 if (!path->nodes[i])
1198                         break;
1199                 if (!path->locks[i])
1200                         break;
1201                 if (!no_skips && path->slots[i] == 0) {
1202                         skip_level = i + 1;
1203                         continue;
1204                 }
1205                 if (!no_skips && path->keep_locks) {
1206                         u32 nritems;
1207                         t = path->nodes[i];
1208                         nritems = btrfs_header_nritems(t);
1209                         if (nritems < 1 || path->slots[i] >= nritems - 1) {
1210                                 skip_level = i + 1;
1211                                 continue;
1212                         }
1213                 }
1214                 if (skip_level < i && i >= lowest_unlock)
1215                         no_skips = 1;
1216
1217                 t = path->nodes[i];
1218                 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
1219                         btrfs_tree_unlock(t);
1220                         path->locks[i] = 0;
1221                 }
1222         }
1223 }
1224
1225 /*
1226  * look for key in the tree.  path is filled in with nodes along the way
1227  * if key is found, we return zero and you can find the item in the leaf
1228  * level of the path (level 0)
1229  *
1230  * If the key isn't found, the path points to the slot where it should
1231  * be inserted, and 1 is returned.  If there are other errors during the
1232  * search a negative error number is returned.
1233  *
1234  * if ins_len > 0, nodes and leaves will be split as we walk down the
1235  * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
1236  * possible)
1237  */
1238 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1239                       *root, struct btrfs_key *key, struct btrfs_path *p, int
1240                       ins_len, int cow)
1241 {
1242         struct extent_buffer *b;
1243         struct extent_buffer *tmp;
1244         int slot;
1245         int ret;
1246         int level;
1247         int should_reada = p->reada;
1248         int lowest_unlock = 1;
1249         int blocksize;
1250         u8 lowest_level = 0;
1251         u64 blocknr;
1252         u64 gen;
1253
1254         lowest_level = p->lowest_level;
1255         WARN_ON(lowest_level && ins_len);
1256         WARN_ON(p->nodes[0] != NULL);
1257         WARN_ON(cow && root == root->fs_info->extent_root &&
1258                 !mutex_is_locked(&root->fs_info->alloc_mutex));
1259         WARN_ON(root == root->fs_info->chunk_root &&
1260                 !mutex_is_locked(&root->fs_info->chunk_mutex));
1261         WARN_ON(root == root->fs_info->dev_root &&
1262                 !mutex_is_locked(&root->fs_info->chunk_mutex));
1263         if (ins_len < 0)
1264                 lowest_unlock = 2;
1265 again:
1266         if (p->skip_locking)
1267                 b = btrfs_root_node(root);
1268         else
1269                 b = btrfs_lock_root_node(root);
1270
1271         while (b) {
1272                 level = btrfs_header_level(b);
1273                 if (cow) {
1274                         int wret;
1275                         wret = btrfs_cow_block(trans, root, b,
1276                                                p->nodes[level + 1],
1277                                                p->slots[level + 1],
1278                                                &b);
1279                         if (wret) {
1280                                 free_extent_buffer(b);
1281                                 return wret;
1282                         }
1283                 }
1284                 BUG_ON(!cow && ins_len);
1285                 if (level != btrfs_header_level(b))
1286                         WARN_ON(1);
1287                 level = btrfs_header_level(b);
1288                 p->nodes[level] = b;
1289                 if (!p->skip_locking)
1290                         p->locks[level] = 1;
1291                 ret = check_block(root, p, level);
1292                 if (ret)
1293                         return -1;
1294
1295                 ret = bin_search(b, key, level, &slot);
1296                 if (level != 0) {
1297                         if (ret && slot > 0)
1298                                 slot -= 1;
1299                         p->slots[level] = slot;
1300                         if (ins_len > 0 && btrfs_header_nritems(b) >=
1301                             BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1302                                 int sret = split_node(trans, root, p, level);
1303                                 BUG_ON(sret > 0);
1304                                 if (sret)
1305                                         return sret;
1306                                 b = p->nodes[level];
1307                                 slot = p->slots[level];
1308                         } else if (ins_len < 0) {
1309                                 int sret = balance_level(trans, root, p,
1310                                                          level);
1311                                 if (sret)
1312                                         return sret;
1313                                 b = p->nodes[level];
1314                                 if (!b) {
1315                                         btrfs_release_path(NULL, p);
1316                                         goto again;
1317                                 }
1318                                 slot = p->slots[level];
1319                                 BUG_ON(btrfs_header_nritems(b) == 1);
1320                         }
1321                         /* this is only true while dropping a snapshot */
1322                         if (level == lowest_level) {
1323                                 unlock_up(p, level, lowest_unlock);
1324                                 break;
1325                         }
1326
1327                         if (should_reada)
1328                                 reada_for_search(root, p, level, slot,
1329                                                  key->objectid);
1330
1331                         blocknr = btrfs_node_blockptr(b, slot);
1332                         gen = btrfs_node_ptr_generation(b, slot);
1333                         blocksize = btrfs_level_size(root, level - 1);
1334
1335                         tmp = btrfs_find_tree_block(root, blocknr, blocksize);
1336                         if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
1337                                 b = tmp;
1338                         } else {
1339                                 /*
1340                                  * reduce lock contention at high levels
1341                                  * of the btree by dropping locks before
1342                                  * we read.
1343                                  */
1344                                 if (level > 1) {
1345                                         btrfs_release_path(NULL, p);
1346                                         if (tmp)
1347                                                 free_extent_buffer(tmp);
1348                                         tmp = read_tree_block(root, blocknr,
1349                                                          blocksize, gen);
1350                                         if (tmp)
1351                                                 free_extent_buffer(tmp);
1352                                         goto again;
1353                                 } else {
1354                                         if (tmp)
1355                                                 free_extent_buffer(tmp);
1356                                         b = read_node_slot(root, b, slot);
1357                                 }
1358                         }
1359                         if (!p->skip_locking)
1360                                 btrfs_tree_lock(b);
1361                         unlock_up(p, level, lowest_unlock);
1362                 } else {
1363                         p->slots[level] = slot;
1364                         if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1365                             sizeof(struct btrfs_item) + ins_len) {
1366                                 int sret = split_leaf(trans, root, key,
1367                                                       p, ins_len, ret == 0);
1368                                 BUG_ON(sret > 0);
1369                                 if (sret)
1370                                         return sret;
1371                         }
1372                         unlock_up(p, level, lowest_unlock);
1373                         return ret;
1374                 }
1375         }
1376         return 1;
1377 }
1378
1379 /*
1380  * adjust the pointers going up the tree, starting at level
1381  * making sure the right key of each node is points to 'key'.
1382  * This is used after shifting pointers to the left, so it stops
1383  * fixing up pointers when a given leaf/node is not in slot 0 of the
1384  * higher levels
1385  *
1386  * If this fails to write a tree block, it returns -1, but continues
1387  * fixing up the blocks in ram so the tree is consistent.
1388  */
1389 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1390                           struct btrfs_root *root, struct btrfs_path *path,
1391                           struct btrfs_disk_key *key, int level)
1392 {
1393         int i;
1394         int ret = 0;
1395         struct extent_buffer *t;
1396
1397         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1398                 int tslot = path->slots[i];
1399                 if (!path->nodes[i])
1400                         break;
1401                 t = path->nodes[i];
1402                 btrfs_set_node_key(t, key, tslot);
1403                 btrfs_mark_buffer_dirty(path->nodes[i]);
1404                 if (tslot != 0)
1405                         break;
1406         }
1407         return ret;
1408 }
1409
1410 /*
1411  * try to push data from one node into the next node left in the
1412  * tree.
1413  *
1414  * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1415  * error, and > 0 if there was no room in the left hand block.
1416  */
1417 static int push_node_left(struct btrfs_trans_handle *trans,
1418                           struct btrfs_root *root, struct extent_buffer *dst,
1419                           struct extent_buffer *src, int empty)
1420 {
1421         int push_items = 0;
1422         int src_nritems;
1423         int dst_nritems;
1424         int ret = 0;
1425
1426         src_nritems = btrfs_header_nritems(src);
1427         dst_nritems = btrfs_header_nritems(dst);
1428         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1429         WARN_ON(btrfs_header_generation(src) != trans->transid);
1430         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1431
1432         if (!empty && src_nritems <= 8)
1433                 return 1;
1434
1435         if (push_items <= 0) {
1436                 return 1;
1437         }
1438
1439         if (empty) {
1440                 push_items = min(src_nritems, push_items);
1441                 if (push_items < src_nritems) {
1442                         /* leave at least 8 pointers in the node if
1443                          * we aren't going to empty it
1444                          */
1445                         if (src_nritems - push_items < 8) {
1446                                 if (push_items <= 8)
1447                                         return 1;
1448                                 push_items -= 8;
1449                         }
1450                 }
1451         } else
1452                 push_items = min(src_nritems - 8, push_items);
1453
1454         copy_extent_buffer(dst, src,
1455                            btrfs_node_key_ptr_offset(dst_nritems),
1456                            btrfs_node_key_ptr_offset(0),
1457                            push_items * sizeof(struct btrfs_key_ptr));
1458
1459         if (push_items < src_nritems) {
1460                 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1461                                       btrfs_node_key_ptr_offset(push_items),
1462                                       (src_nritems - push_items) *
1463                                       sizeof(struct btrfs_key_ptr));
1464         }
1465         btrfs_set_header_nritems(src, src_nritems - push_items);
1466         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1467         btrfs_mark_buffer_dirty(src);
1468         btrfs_mark_buffer_dirty(dst);
1469         return ret;
1470 }
1471
1472 /*
1473  * try to push data from one node into the next node right in the
1474  * tree.
1475  *
1476  * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1477  * error, and > 0 if there was no room in the right hand block.
1478  *
1479  * this will  only push up to 1/2 the contents of the left node over
1480  */
1481 static int balance_node_right(struct btrfs_trans_handle *trans,
1482                               struct btrfs_root *root,
1483                               struct extent_buffer *dst,
1484                               struct extent_buffer *src)
1485 {
1486         int push_items = 0;
1487         int max_push;
1488         int src_nritems;
1489         int dst_nritems;
1490         int ret = 0;
1491
1492         WARN_ON(btrfs_header_generation(src) != trans->transid);
1493         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1494
1495         src_nritems = btrfs_header_nritems(src);
1496         dst_nritems = btrfs_header_nritems(dst);
1497         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1498         if (push_items <= 0) {
1499                 return 1;
1500         }
1501
1502         if (src_nritems < 4) {
1503                 return 1;
1504         }
1505
1506         max_push = src_nritems / 2 + 1;
1507         /* don't try to empty the node */
1508         if (max_push >= src_nritems) {
1509                 return 1;
1510         }
1511
1512         if (max_push < push_items)
1513                 push_items = max_push;
1514
1515         memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1516                                       btrfs_node_key_ptr_offset(0),
1517                                       (dst_nritems) *
1518                                       sizeof(struct btrfs_key_ptr));
1519
1520         copy_extent_buffer(dst, src,
1521                            btrfs_node_key_ptr_offset(0),
1522                            btrfs_node_key_ptr_offset(src_nritems - push_items),
1523                            push_items * sizeof(struct btrfs_key_ptr));
1524
1525         btrfs_set_header_nritems(src, src_nritems - push_items);
1526         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1527
1528         btrfs_mark_buffer_dirty(src);
1529         btrfs_mark_buffer_dirty(dst);
1530         return ret;
1531 }
1532
1533 /*
1534  * helper function to insert a new root level in the tree.
1535  * A new node is allocated, and a single item is inserted to
1536  * point to the existing root
1537  *
1538  * returns zero on success or < 0 on failure.
1539  */
1540 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1541                            struct btrfs_root *root,
1542                            struct btrfs_path *path, int level)
1543 {
1544         u64 root_gen;
1545         u64 lower_gen;
1546         struct extent_buffer *lower;
1547         struct extent_buffer *c;
1548         struct extent_buffer *old;
1549         struct btrfs_disk_key lower_key;
1550
1551         BUG_ON(path->nodes[level]);
1552         BUG_ON(path->nodes[level-1] != root->node);
1553
1554         if (root->ref_cows)
1555                 root_gen = trans->transid;
1556         else
1557                 root_gen = 0;
1558
1559         lower = path->nodes[level-1];
1560         if (level == 1)
1561                 btrfs_item_key(lower, &lower_key, 0);
1562         else
1563                 btrfs_node_key(lower, &lower_key, 0);
1564
1565         c = btrfs_alloc_free_block(trans, root, root->nodesize,
1566                                    root->root_key.objectid,
1567                                    root_gen, lower_key.objectid, level,
1568                                    root->node->start, 0);
1569         if (IS_ERR(c))
1570                 return PTR_ERR(c);
1571
1572         memset_extent_buffer(c, 0, 0, root->nodesize);
1573         btrfs_set_header_nritems(c, 1);
1574         btrfs_set_header_level(c, level);
1575         btrfs_set_header_bytenr(c, c->start);
1576         btrfs_set_header_generation(c, trans->transid);
1577         btrfs_set_header_owner(c, root->root_key.objectid);
1578
1579         write_extent_buffer(c, root->fs_info->fsid,
1580                             (unsigned long)btrfs_header_fsid(c),
1581                             BTRFS_FSID_SIZE);
1582
1583         write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1584                             (unsigned long)btrfs_header_chunk_tree_uuid(c),
1585                             BTRFS_UUID_SIZE);
1586
1587         btrfs_set_node_key(c, &lower_key, 0);
1588         btrfs_set_node_blockptr(c, 0, lower->start);
1589         lower_gen = btrfs_header_generation(lower);
1590         WARN_ON(lower_gen == 0);
1591
1592         btrfs_set_node_ptr_generation(c, 0, lower_gen);
1593
1594         btrfs_mark_buffer_dirty(c);
1595
1596         spin_lock(&root->node_lock);
1597         old = root->node;
1598         root->node = c;
1599         spin_unlock(&root->node_lock);
1600
1601         /* the super has an extra ref to root->node */
1602         free_extent_buffer(old);
1603
1604         add_root_to_dirty_list(root);
1605         extent_buffer_get(c);
1606         path->nodes[level] = c;
1607         path->locks[level] = 1;
1608         path->slots[level] = 0;
1609
1610         if (root->ref_cows && lower_gen != trans->transid) {
1611                 struct btrfs_path *back_path = btrfs_alloc_path();
1612                 int ret;
1613                 mutex_lock(&root->fs_info->alloc_mutex);
1614                 ret = btrfs_insert_extent_backref(trans,
1615                                                   root->fs_info->extent_root,
1616                                                   path, lower->start,
1617                                                   root->root_key.objectid,
1618                                                   trans->transid, 0, 0);
1619                 BUG_ON(ret);
1620                 mutex_unlock(&root->fs_info->alloc_mutex);
1621                 btrfs_free_path(back_path);
1622         }
1623         return 0;
1624 }
1625
1626 /*
1627  * worker function to insert a single pointer in a node.
1628  * the node should have enough room for the pointer already
1629  *
1630  * slot and level indicate where you want the key to go, and
1631  * blocknr is the block the key points to.
1632  *
1633  * returns zero on success and < 0 on any error
1634  */
1635 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1636                       *root, struct btrfs_path *path, struct btrfs_disk_key
1637                       *key, u64 bytenr, int slot, int level)
1638 {
1639         struct extent_buffer *lower;
1640         int nritems;
1641
1642         BUG_ON(!path->nodes[level]);
1643         lower = path->nodes[level];
1644         nritems = btrfs_header_nritems(lower);
1645         if (slot > nritems)
1646                 BUG();
1647         if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1648                 BUG();
1649         if (slot != nritems) {
1650                 memmove_extent_buffer(lower,
1651                               btrfs_node_key_ptr_offset(slot + 1),
1652                               btrfs_node_key_ptr_offset(slot),
1653                               (nritems - slot) * sizeof(struct btrfs_key_ptr));
1654         }
1655         btrfs_set_node_key(lower, key, slot);
1656         btrfs_set_node_blockptr(lower, slot, bytenr);
1657         WARN_ON(trans->transid == 0);
1658         btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1659         btrfs_set_header_nritems(lower, nritems + 1);
1660         btrfs_mark_buffer_dirty(lower);
1661         return 0;
1662 }
1663
1664 /*
1665  * split the node at the specified level in path in two.
1666  * The path is corrected to point to the appropriate node after the split
1667  *
1668  * Before splitting this tries to make some room in the node by pushing
1669  * left and right, if either one works, it returns right away.
1670  *
1671  * returns 0 on success and < 0 on failure
1672  */
1673 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1674                       *root, struct btrfs_path *path, int level)
1675 {
1676         u64 root_gen;
1677         struct extent_buffer *c;
1678         struct extent_buffer *split;
1679         struct btrfs_disk_key disk_key;
1680         int mid;
1681         int ret;
1682         int wret;
1683         u32 c_nritems;
1684
1685         c = path->nodes[level];
1686         WARN_ON(btrfs_header_generation(c) != trans->transid);
1687         if (c == root->node) {
1688                 /* trying to split the root, lets make a new one */
1689                 ret = insert_new_root(trans, root, path, level + 1);
1690                 if (ret)
1691                         return ret;
1692         } else {
1693                 ret = push_nodes_for_insert(trans, root, path, level);
1694                 c = path->nodes[level];
1695                 if (!ret && btrfs_header_nritems(c) <
1696                     BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1697                         return 0;
1698                 if (ret < 0)
1699                         return ret;
1700         }
1701
1702         c_nritems = btrfs_header_nritems(c);
1703         if (root->ref_cows)
1704                 root_gen = trans->transid;
1705         else
1706                 root_gen = 0;
1707
1708         btrfs_node_key(c, &disk_key, 0);
1709         split = btrfs_alloc_free_block(trans, root, root->nodesize,
1710                                          root->root_key.objectid,
1711                                          root_gen,
1712                                          btrfs_disk_key_objectid(&disk_key),
1713                                          level, c->start, 0);
1714         if (IS_ERR(split))
1715                 return PTR_ERR(split);
1716
1717         btrfs_set_header_flags(split, btrfs_header_flags(c));
1718         btrfs_set_header_level(split, btrfs_header_level(c));
1719         btrfs_set_header_bytenr(split, split->start);
1720         btrfs_set_header_generation(split, trans->transid);
1721         btrfs_set_header_owner(split, root->root_key.objectid);
1722         btrfs_set_header_flags(split, 0);
1723         write_extent_buffer(split, root->fs_info->fsid,
1724                             (unsigned long)btrfs_header_fsid(split),
1725                             BTRFS_FSID_SIZE);
1726         write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1727                             (unsigned long)btrfs_header_chunk_tree_uuid(split),
1728                             BTRFS_UUID_SIZE);
1729
1730         mid = (c_nritems + 1) / 2;
1731
1732         copy_extent_buffer(split, c,
1733                            btrfs_node_key_ptr_offset(0),
1734                            btrfs_node_key_ptr_offset(mid),
1735                            (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1736         btrfs_set_header_nritems(split, c_nritems - mid);
1737         btrfs_set_header_nritems(c, mid);
1738         ret = 0;
1739
1740         btrfs_mark_buffer_dirty(c);
1741         btrfs_mark_buffer_dirty(split);
1742
1743         btrfs_node_key(split, &disk_key, 0);
1744         wret = insert_ptr(trans, root, path, &disk_key, split->start,
1745                           path->slots[level + 1] + 1,
1746                           level + 1);
1747         if (wret)
1748                 ret = wret;
1749
1750         if (path->slots[level] >= mid) {
1751                 path->slots[level] -= mid;
1752                 btrfs_tree_unlock(c);
1753                 free_extent_buffer(c);
1754                 path->nodes[level] = split;
1755                 path->slots[level + 1] += 1;
1756         } else {
1757                 btrfs_tree_unlock(split);
1758                 free_extent_buffer(split);
1759         }
1760         return ret;
1761 }
1762
1763 /*
1764  * how many bytes are required to store the items in a leaf.  start
1765  * and nr indicate which items in the leaf to check.  This totals up the
1766  * space used both by the item structs and the item data
1767  */
1768 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1769 {
1770         int data_len;
1771         int nritems = btrfs_header_nritems(l);
1772         int end = min(nritems, start + nr) - 1;
1773
1774         if (!nr)
1775                 return 0;
1776         data_len = btrfs_item_end_nr(l, start);
1777         data_len = data_len - btrfs_item_offset_nr(l, end);
1778         data_len += sizeof(struct btrfs_item) * nr;
1779         WARN_ON(data_len < 0);
1780         return data_len;
1781 }
1782
1783 /*
1784  * The space between the end of the leaf items and
1785  * the start of the leaf data.  IOW, how much room
1786  * the leaf has left for both items and data
1787  */
1788 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1789 {
1790         int nritems = btrfs_header_nritems(leaf);
1791         int ret;
1792         ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1793         if (ret < 0) {
1794                 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1795                        ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1796                        leaf_space_used(leaf, 0, nritems), nritems);
1797         }
1798         return ret;
1799 }
1800
1801 /*
1802  * push some data in the path leaf to the right, trying to free up at
1803  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1804  *
1805  * returns 1 if the push failed because the other node didn't have enough
1806  * room, 0 if everything worked out and < 0 if there were major errors.
1807  */
1808 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1809                            *root, struct btrfs_path *path, int data_size,
1810                            int empty)
1811 {
1812         struct extent_buffer *left = path->nodes[0];
1813         struct extent_buffer *right;
1814         struct extent_buffer *upper;
1815         struct btrfs_disk_key disk_key;
1816         int slot;
1817         u32 i;
1818         int free_space;
1819         int push_space = 0;
1820         int push_items = 0;
1821         struct btrfs_item *item;
1822         u32 left_nritems;
1823         u32 nr;
1824         u32 right_nritems;
1825         u32 data_end;
1826         u32 this_item_size;
1827         int ret;
1828
1829         slot = path->slots[1];
1830         if (!path->nodes[1]) {
1831                 return 1;
1832         }
1833         upper = path->nodes[1];
1834         if (slot >= btrfs_header_nritems(upper) - 1)
1835                 return 1;
1836
1837         WARN_ON(!btrfs_tree_locked(path->nodes[1]));
1838
1839         right = read_node_slot(root, upper, slot + 1);
1840         btrfs_tree_lock(right);
1841         free_space = btrfs_leaf_free_space(root, right);
1842         if (free_space < data_size + sizeof(struct btrfs_item))
1843                 goto out_unlock;
1844
1845         /* cow and double check */
1846         ret = btrfs_cow_block(trans, root, right, upper,
1847                               slot + 1, &right);
1848         if (ret)
1849                 goto out_unlock;
1850
1851         free_space = btrfs_leaf_free_space(root, right);
1852         if (free_space < data_size + sizeof(struct btrfs_item))
1853                 goto out_unlock;
1854
1855         left_nritems = btrfs_header_nritems(left);
1856         if (left_nritems == 0)
1857                 goto out_unlock;
1858
1859         if (empty)
1860                 nr = 0;
1861         else
1862                 nr = 1;
1863
1864         i = left_nritems - 1;
1865         while (i >= nr) {
1866                 item = btrfs_item_nr(left, i);
1867
1868                 if (path->slots[0] == i)
1869                         push_space += data_size + sizeof(*item);
1870
1871                 if (!left->map_token) {
1872                         map_extent_buffer(left, (unsigned long)item,
1873                                         sizeof(struct btrfs_item),
1874                                         &left->map_token, &left->kaddr,
1875                                         &left->map_start, &left->map_len,
1876                                         KM_USER1);
1877                 }
1878
1879                 this_item_size = btrfs_item_size(left, item);
1880                 if (this_item_size + sizeof(*item) + push_space > free_space)
1881                         break;
1882                 push_items++;
1883                 push_space += this_item_size + sizeof(*item);
1884                 if (i == 0)
1885                         break;
1886                 i--;
1887         }
1888         if (left->map_token) {
1889                 unmap_extent_buffer(left, left->map_token, KM_USER1);
1890                 left->map_token = NULL;
1891         }
1892
1893         if (push_items == 0)
1894                 goto out_unlock;
1895
1896         if (!empty && push_items == left_nritems)
1897                 WARN_ON(1);
1898
1899         /* push left to right */
1900         right_nritems = btrfs_header_nritems(right);
1901
1902         push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1903         push_space -= leaf_data_end(root, left);
1904
1905         /* make room in the right data area */
1906         data_end = leaf_data_end(root, right);
1907         memmove_extent_buffer(right,
1908                               btrfs_leaf_data(right) + data_end - push_space,
1909                               btrfs_leaf_data(right) + data_end,
1910                               BTRFS_LEAF_DATA_SIZE(root) - data_end);
1911
1912         /* copy from the left data area */
1913         copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1914                      BTRFS_LEAF_DATA_SIZE(root) - push_space,
1915                      btrfs_leaf_data(left) + leaf_data_end(root, left),
1916                      push_space);
1917
1918         memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1919                               btrfs_item_nr_offset(0),
1920                               right_nritems * sizeof(struct btrfs_item));
1921
1922         /* copy the items from left to right */
1923         copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1924                    btrfs_item_nr_offset(left_nritems - push_items),
1925                    push_items * sizeof(struct btrfs_item));
1926
1927         /* update the item pointers */
1928         right_nritems += push_items;
1929         btrfs_set_header_nritems(right, right_nritems);
1930         push_space = BTRFS_LEAF_DATA_SIZE(root);
1931         for (i = 0; i < right_nritems; i++) {
1932                 item = btrfs_item_nr(right, i);
1933                 if (!right->map_token) {
1934                         map_extent_buffer(right, (unsigned long)item,
1935                                         sizeof(struct btrfs_item),
1936                                         &right->map_token, &right->kaddr,
1937                                         &right->map_start, &right->map_len,
1938                                         KM_USER1);
1939                 }
1940                 push_space -= btrfs_item_size(right, item);
1941                 btrfs_set_item_offset(right, item, push_space);
1942         }
1943
1944         if (right->map_token) {
1945                 unmap_extent_buffer(right, right->map_token, KM_USER1);
1946                 right->map_token = NULL;
1947         }
1948         left_nritems -= push_items;
1949         btrfs_set_header_nritems(left, left_nritems);
1950
1951         if (left_nritems)
1952                 btrfs_mark_buffer_dirty(left);
1953         btrfs_mark_buffer_dirty(right);
1954
1955         btrfs_item_key(right, &disk_key, 0);
1956         btrfs_set_node_key(upper, &disk_key, slot + 1);
1957         btrfs_mark_buffer_dirty(upper);
1958
1959         /* then fixup the leaf pointer in the path */
1960         if (path->slots[0] >= left_nritems) {
1961                 path->slots[0] -= left_nritems;
1962                 if (btrfs_header_nritems(path->nodes[0]) == 0)
1963                         clean_tree_block(trans, root, path->nodes[0]);
1964                 btrfs_tree_unlock(path->nodes[0]);
1965                 free_extent_buffer(path->nodes[0]);
1966                 path->nodes[0] = right;
1967                 path->slots[1] += 1;
1968         } else {
1969                 btrfs_tree_unlock(right);
1970                 free_extent_buffer(right);
1971         }
1972         return 0;
1973
1974 out_unlock:
1975         btrfs_tree_unlock(right);
1976         free_extent_buffer(right);
1977         return 1;
1978 }
1979
1980 /*
1981  * push some data in the path leaf to the left, trying to free up at
1982  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1983  */
1984 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1985                           *root, struct btrfs_path *path, int data_size,
1986                           int empty)
1987 {
1988         struct btrfs_disk_key disk_key;
1989         struct extent_buffer *right = path->nodes[0];
1990         struct extent_buffer *left;
1991         int slot;
1992         int i;
1993         int free_space;
1994         int push_space = 0;
1995         int push_items = 0;
1996         struct btrfs_item *item;
1997         u32 old_left_nritems;
1998         u32 right_nritems;
1999         u32 nr;
2000         int ret = 0;
2001         int wret;
2002         u32 this_item_size;
2003         u32 old_left_item_size;
2004
2005         slot = path->slots[1];
2006         if (slot == 0)
2007                 return 1;
2008         if (!path->nodes[1])
2009                 return 1;
2010
2011         right_nritems = btrfs_header_nritems(right);
2012         if (right_nritems == 0) {
2013                 return 1;
2014         }
2015
2016         WARN_ON(!btrfs_tree_locked(path->nodes[1]));
2017
2018         left = read_node_slot(root, path->nodes[1], slot - 1);
2019         btrfs_tree_lock(left);
2020         free_space = btrfs_leaf_free_space(root, left);
2021         if (free_space < data_size + sizeof(struct btrfs_item)) {
2022                 ret = 1;
2023                 goto out;
2024         }
2025
2026         /* cow and double check */
2027         ret = btrfs_cow_block(trans, root, left,
2028                               path->nodes[1], slot - 1, &left);
2029         if (ret) {
2030                 /* we hit -ENOSPC, but it isn't fatal here */
2031                 ret = 1;
2032                 goto out;
2033         }
2034
2035         free_space = btrfs_leaf_free_space(root, left);
2036         if (free_space < data_size + sizeof(struct btrfs_item)) {
2037                 ret = 1;
2038                 goto out;
2039         }
2040
2041         if (empty)
2042                 nr = right_nritems;
2043         else
2044                 nr = right_nritems - 1;
2045
2046         for (i = 0; i < nr; i++) {
2047                 item = btrfs_item_nr(right, i);
2048                 if (!right->map_token) {
2049                         map_extent_buffer(right, (unsigned long)item,
2050                                         sizeof(struct btrfs_item),
2051                                         &right->map_token, &right->kaddr,
2052                                         &right->map_start, &right->map_len,
2053                                         KM_USER1);
2054                 }
2055
2056                 if (path->slots[0] == i)
2057                         push_space += data_size + sizeof(*item);
2058
2059                 this_item_size = btrfs_item_size(right, item);
2060                 if (this_item_size + sizeof(*item) + push_space > free_space)
2061                         break;
2062
2063                 push_items++;
2064                 push_space += this_item_size + sizeof(*item);
2065         }
2066
2067         if (right->map_token) {
2068                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2069                 right->map_token = NULL;
2070         }
2071
2072         if (push_items == 0) {
2073                 ret = 1;
2074                 goto out;
2075         }
2076         if (!empty && push_items == btrfs_header_nritems(right))
2077                 WARN_ON(1);
2078
2079         /* push data from right to left */
2080         copy_extent_buffer(left, right,
2081                            btrfs_item_nr_offset(btrfs_header_nritems(left)),
2082                            btrfs_item_nr_offset(0),
2083                            push_items * sizeof(struct btrfs_item));
2084
2085         push_space = BTRFS_LEAF_DATA_SIZE(root) -
2086                      btrfs_item_offset_nr(right, push_items -1);
2087
2088         copy_extent_buffer(left, right, btrfs_leaf_data(left) +
2089                      leaf_data_end(root, left) - push_space,
2090                      btrfs_leaf_data(right) +
2091                      btrfs_item_offset_nr(right, push_items - 1),
2092                      push_space);
2093         old_left_nritems = btrfs_header_nritems(left);
2094         BUG_ON(old_left_nritems < 0);
2095
2096         old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
2097         for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
2098                 u32 ioff;
2099
2100                 item = btrfs_item_nr(left, i);
2101                 if (!left->map_token) {
2102                         map_extent_buffer(left, (unsigned long)item,
2103                                         sizeof(struct btrfs_item),
2104                                         &left->map_token, &left->kaddr,
2105                                         &left->map_start, &left->map_len,
2106                                         KM_USER1);
2107                 }
2108
2109                 ioff = btrfs_item_offset(left, item);
2110                 btrfs_set_item_offset(left, item,
2111                       ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
2112         }
2113         btrfs_set_header_nritems(left, old_left_nritems + push_items);
2114         if (left->map_token) {
2115                 unmap_extent_buffer(left, left->map_token, KM_USER1);
2116                 left->map_token = NULL;
2117         }
2118
2119         /* fixup right node */
2120         if (push_items > right_nritems) {
2121                 printk("push items %d nr %u\n", push_items, right_nritems);
2122                 WARN_ON(1);
2123         }
2124
2125         if (push_items < right_nritems) {
2126                 push_space = btrfs_item_offset_nr(right, push_items - 1) -
2127                                                   leaf_data_end(root, right);
2128                 memmove_extent_buffer(right, btrfs_leaf_data(right) +
2129                                       BTRFS_LEAF_DATA_SIZE(root) - push_space,
2130                                       btrfs_leaf_data(right) +
2131                                       leaf_data_end(root, right), push_space);
2132
2133                 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
2134                               btrfs_item_nr_offset(push_items),
2135                              (btrfs_header_nritems(right) - push_items) *
2136                              sizeof(struct btrfs_item));
2137         }
2138         right_nritems -= push_items;
2139         btrfs_set_header_nritems(right, right_nritems);
2140         push_space = BTRFS_LEAF_DATA_SIZE(root);
2141         for (i = 0; i < right_nritems; i++) {
2142                 item = btrfs_item_nr(right, i);
2143
2144                 if (!right->map_token) {
2145                         map_extent_buffer(right, (unsigned long)item,
2146                                         sizeof(struct btrfs_item),
2147                                         &right->map_token, &right->kaddr,
2148                                         &right->map_start, &right->map_len,
2149                                         KM_USER1);
2150                 }
2151
2152                 push_space = push_space - btrfs_item_size(right, item);
2153                 btrfs_set_item_offset(right, item, push_space);
2154         }
2155         if (right->map_token) {
2156                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2157                 right->map_token = NULL;
2158         }
2159
2160         btrfs_mark_buffer_dirty(left);
2161         if (right_nritems)
2162                 btrfs_mark_buffer_dirty(right);
2163
2164         btrfs_item_key(right, &disk_key, 0);
2165         wret = fixup_low_keys(trans, root, path, &disk_key, 1);
2166         if (wret)
2167                 ret = wret;
2168
2169         /* then fixup the leaf pointer in the path */
2170         if (path->slots[0] < push_items) {
2171                 path->slots[0] += old_left_nritems;
2172                 if (btrfs_header_nritems(path->nodes[0]) == 0)
2173                         clean_tree_block(trans, root, path->nodes[0]);
2174                 btrfs_tree_unlock(path->nodes[0]);
2175                 free_extent_buffer(path->nodes[0]);
2176                 path->nodes[0] = left;
2177                 path->slots[1] -= 1;
2178         } else {
2179                 btrfs_tree_unlock(left);
2180                 free_extent_buffer(left);
2181                 path->slots[0] -= push_items;
2182         }
2183         BUG_ON(path->slots[0] < 0);
2184         return ret;
2185 out:
2186         btrfs_tree_unlock(left);
2187         free_extent_buffer(left);
2188         return ret;
2189 }
2190
2191 /*
2192  * split the path's leaf in two, making sure there is at least data_size
2193  * available for the resulting leaf level of the path.
2194  *
2195  * returns 0 if all went well and < 0 on failure.
2196  */
2197 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
2198                       *root, struct btrfs_key *ins_key,
2199                       struct btrfs_path *path, int data_size, int extend)
2200 {
2201         u64 root_gen;
2202         struct extent_buffer *l;
2203         u32 nritems;
2204         int mid;
2205         int slot;
2206         struct extent_buffer *right;
2207         int space_needed = data_size + sizeof(struct btrfs_item);
2208         int data_copy_size;
2209         int rt_data_off;
2210         int i;
2211         int ret = 0;
2212         int wret;
2213         int double_split;
2214         int num_doubles = 0;
2215         struct btrfs_disk_key disk_key;
2216
2217         if (extend)
2218                 space_needed = data_size;
2219
2220         if (root->ref_cows)
2221                 root_gen = trans->transid;
2222         else
2223                 root_gen = 0;
2224
2225         /* first try to make some room by pushing left and right */
2226         if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
2227                 wret = push_leaf_right(trans, root, path, data_size, 0);
2228                 if (wret < 0) {
2229                         return wret;
2230                 }
2231                 if (wret) {
2232                         wret = push_leaf_left(trans, root, path, data_size, 0);
2233                         if (wret < 0)
2234                                 return wret;
2235                 }
2236                 l = path->nodes[0];
2237
2238                 /* did the pushes work? */
2239                 if (btrfs_leaf_free_space(root, l) >= space_needed)
2240                         return 0;
2241         }
2242
2243         if (!path->nodes[1]) {
2244                 ret = insert_new_root(trans, root, path, 1);
2245                 if (ret)
2246                         return ret;
2247         }
2248 again:
2249         double_split = 0;
2250         l = path->nodes[0];
2251         slot = path->slots[0];
2252         nritems = btrfs_header_nritems(l);
2253         mid = (nritems + 1)/ 2;
2254
2255         btrfs_item_key(l, &disk_key, 0);
2256
2257         right = btrfs_alloc_free_block(trans, root, root->leafsize,
2258                                          root->root_key.objectid,
2259                                          root_gen, disk_key.objectid, 0,
2260                                          l->start, 0);
2261         if (IS_ERR(right)) {
2262                 BUG_ON(1);
2263                 return PTR_ERR(right);
2264         }
2265
2266         memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2267         btrfs_set_header_bytenr(right, right->start);
2268         btrfs_set_header_generation(right, trans->transid);
2269         btrfs_set_header_owner(right, root->root_key.objectid);
2270         btrfs_set_header_level(right, 0);
2271         write_extent_buffer(right, root->fs_info->fsid,
2272                             (unsigned long)btrfs_header_fsid(right),
2273                             BTRFS_FSID_SIZE);
2274
2275         write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2276                             (unsigned long)btrfs_header_chunk_tree_uuid(right),
2277                             BTRFS_UUID_SIZE);
2278         if (mid <= slot) {
2279                 if (nritems == 1 ||
2280                     leaf_space_used(l, mid, nritems - mid) + space_needed >
2281                         BTRFS_LEAF_DATA_SIZE(root)) {
2282                         if (slot >= nritems) {
2283                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2284                                 btrfs_set_header_nritems(right, 0);
2285                                 wret = insert_ptr(trans, root, path,
2286                                                   &disk_key, right->start,
2287                                                   path->slots[1] + 1, 1);
2288                                 if (wret)
2289                                         ret = wret;
2290
2291                                 btrfs_tree_unlock(path->nodes[0]);
2292                                 free_extent_buffer(path->nodes[0]);
2293                                 path->nodes[0] = right;
2294                                 path->slots[0] = 0;
2295                                 path->slots[1] += 1;
2296                                 btrfs_mark_buffer_dirty(right);
2297                                 return ret;
2298                         }
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         } else {
2307                 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2308                         BTRFS_LEAF_DATA_SIZE(root)) {
2309                         if (!extend && slot == 0) {
2310                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2311                                 btrfs_set_header_nritems(right, 0);
2312                                 wret = insert_ptr(trans, root, path,
2313                                                   &disk_key,
2314                                                   right->start,
2315                                                   path->slots[1], 1);
2316                                 if (wret)
2317                                         ret = wret;
2318                                 btrfs_tree_unlock(path->nodes[0]);
2319                                 free_extent_buffer(path->nodes[0]);
2320                                 path->nodes[0] = right;
2321                                 path->slots[0] = 0;
2322                                 if (path->slots[1] == 0) {
2323                                         wret = fixup_low_keys(trans, root,
2324                                                    path, &disk_key, 1);
2325                                         if (wret)
2326                                                 ret = wret;
2327                                 }
2328                                 btrfs_mark_buffer_dirty(right);
2329                                 return ret;
2330                         } else if (extend && slot == 0) {
2331                                 mid = 1;
2332                         } else {
2333                                 mid = slot;
2334                                 if (mid != nritems &&
2335                                     leaf_space_used(l, mid, nritems - mid) +
2336                                     space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2337                                         double_split = 1;
2338                                 }
2339                         }
2340                 }
2341         }
2342         nritems = nritems - mid;
2343         btrfs_set_header_nritems(right, nritems);
2344         data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2345
2346         copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2347                            btrfs_item_nr_offset(mid),
2348                            nritems * sizeof(struct btrfs_item));
2349
2350         copy_extent_buffer(right, l,
2351                      btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2352                      data_copy_size, btrfs_leaf_data(l) +
2353                      leaf_data_end(root, l), data_copy_size);
2354
2355         rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2356                       btrfs_item_end_nr(l, mid);
2357
2358         for (i = 0; i < nritems; i++) {
2359                 struct btrfs_item *item = btrfs_item_nr(right, i);
2360                 u32 ioff;
2361
2362                 if (!right->map_token) {
2363                         map_extent_buffer(right, (unsigned long)item,
2364                                         sizeof(struct btrfs_item),
2365                                         &right->map_token, &right->kaddr,
2366                                         &right->map_start, &right->map_len,
2367                                         KM_USER1);
2368                 }
2369
2370                 ioff = btrfs_item_offset(right, item);
2371                 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2372         }
2373
2374         if (right->map_token) {
2375                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2376                 right->map_token = NULL;
2377         }
2378
2379         btrfs_set_header_nritems(l, mid);
2380         ret = 0;
2381         btrfs_item_key(right, &disk_key, 0);
2382         wret = insert_ptr(trans, root, path, &disk_key, right->start,
2383                           path->slots[1] + 1, 1);
2384         if (wret)
2385                 ret = wret;
2386
2387         btrfs_mark_buffer_dirty(right);
2388         btrfs_mark_buffer_dirty(l);
2389         BUG_ON(path->slots[0] != slot);
2390
2391         if (mid <= slot) {
2392                 btrfs_tree_unlock(path->nodes[0]);
2393                 free_extent_buffer(path->nodes[0]);
2394                 path->nodes[0] = right;
2395                 path->slots[0] -= mid;
2396                 path->slots[1] += 1;
2397         } else {
2398                 btrfs_tree_unlock(right);
2399                 free_extent_buffer(right);
2400         }
2401
2402         BUG_ON(path->slots[0] < 0);
2403
2404         if (double_split) {
2405                 BUG_ON(num_doubles != 0);
2406                 num_doubles++;
2407                 goto again;
2408         }
2409         return ret;
2410 }
2411
2412 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2413                         struct btrfs_root *root,
2414                         struct btrfs_path *path,
2415                         u32 new_size, int from_end)
2416 {
2417         int ret = 0;
2418         int slot;
2419         int slot_orig;
2420         struct extent_buffer *leaf;
2421         struct btrfs_item *item;
2422         u32 nritems;
2423         unsigned int data_end;
2424         unsigned int old_data_start;
2425         unsigned int old_size;
2426         unsigned int size_diff;
2427         int i;
2428
2429         slot_orig = path->slots[0];
2430         leaf = path->nodes[0];
2431         slot = path->slots[0];
2432
2433         old_size = btrfs_item_size_nr(leaf, slot);
2434         if (old_size == new_size)
2435                 return 0;
2436
2437         nritems = btrfs_header_nritems(leaf);
2438         data_end = leaf_data_end(root, leaf);
2439
2440         old_data_start = btrfs_item_offset_nr(leaf, slot);
2441
2442         size_diff = old_size - new_size;
2443
2444         BUG_ON(slot < 0);
2445         BUG_ON(slot >= nritems);
2446
2447         /*
2448          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2449          */
2450         /* first correct the data pointers */
2451         for (i = slot; i < nritems; i++) {
2452                 u32 ioff;
2453                 item = btrfs_item_nr(leaf, i);
2454
2455                 if (!leaf->map_token) {
2456                         map_extent_buffer(leaf, (unsigned long)item,
2457                                         sizeof(struct btrfs_item),
2458                                         &leaf->map_token, &leaf->kaddr,
2459                                         &leaf->map_start, &leaf->map_len,
2460                                         KM_USER1);
2461                 }
2462
2463                 ioff = btrfs_item_offset(leaf, item);
2464                 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2465         }
2466
2467         if (leaf->map_token) {
2468                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2469                 leaf->map_token = NULL;
2470         }
2471
2472         /* shift the data */
2473         if (from_end) {
2474                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2475                               data_end + size_diff, btrfs_leaf_data(leaf) +
2476                               data_end, old_data_start + new_size - data_end);
2477         } else {
2478                 struct btrfs_disk_key disk_key;
2479                 u64 offset;
2480
2481                 btrfs_item_key(leaf, &disk_key, slot);
2482
2483                 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2484                         unsigned long ptr;
2485                         struct btrfs_file_extent_item *fi;
2486
2487                         fi = btrfs_item_ptr(leaf, slot,
2488                                             struct btrfs_file_extent_item);
2489                         fi = (struct btrfs_file_extent_item *)(
2490                              (unsigned long)fi - size_diff);
2491
2492                         if (btrfs_file_extent_type(leaf, fi) ==
2493                             BTRFS_FILE_EXTENT_INLINE) {
2494                                 ptr = btrfs_item_ptr_offset(leaf, slot);
2495                                 memmove_extent_buffer(leaf, ptr,
2496                                         (unsigned long)fi,
2497                                         offsetof(struct btrfs_file_extent_item,
2498                                                  disk_bytenr));
2499                         }
2500                 }
2501
2502                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2503                               data_end + size_diff, btrfs_leaf_data(leaf) +
2504                               data_end, old_data_start - data_end);
2505
2506                 offset = btrfs_disk_key_offset(&disk_key);
2507                 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2508                 btrfs_set_item_key(leaf, &disk_key, slot);
2509                 if (slot == 0)
2510                         fixup_low_keys(trans, root, path, &disk_key, 1);
2511         }
2512
2513         item = btrfs_item_nr(leaf, slot);
2514         btrfs_set_item_size(leaf, item, new_size);
2515         btrfs_mark_buffer_dirty(leaf);
2516
2517         ret = 0;
2518         if (btrfs_leaf_free_space(root, leaf) < 0) {
2519                 btrfs_print_leaf(root, leaf);
2520                 BUG();
2521         }
2522         return ret;
2523 }
2524
2525 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2526                       struct btrfs_root *root, struct btrfs_path *path,
2527                       u32 data_size)
2528 {
2529         int ret = 0;
2530         int slot;
2531         int slot_orig;
2532         struct extent_buffer *leaf;
2533         struct btrfs_item *item;
2534         u32 nritems;
2535         unsigned int data_end;
2536         unsigned int old_data;
2537         unsigned int old_size;
2538         int i;
2539
2540         slot_orig = path->slots[0];
2541         leaf = path->nodes[0];
2542
2543         nritems = btrfs_header_nritems(leaf);
2544         data_end = leaf_data_end(root, leaf);
2545
2546         if (btrfs_leaf_free_space(root, leaf) < data_size) {
2547                 btrfs_print_leaf(root, leaf);
2548                 BUG();
2549         }
2550         slot = path->slots[0];
2551         old_data = btrfs_item_end_nr(leaf, slot);
2552
2553         BUG_ON(slot < 0);
2554         if (slot >= nritems) {
2555                 btrfs_print_leaf(root, leaf);
2556                 printk("slot %d too large, nritems %d\n", slot, nritems);
2557                 BUG_ON(1);
2558         }
2559
2560         /*
2561          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2562          */
2563         /* first correct the data pointers */
2564         for (i = slot; i < nritems; i++) {
2565                 u32 ioff;
2566                 item = btrfs_item_nr(leaf, i);
2567
2568                 if (!leaf->map_token) {
2569                         map_extent_buffer(leaf, (unsigned long)item,
2570                                         sizeof(struct btrfs_item),
2571                                         &leaf->map_token, &leaf->kaddr,
2572                                         &leaf->map_start, &leaf->map_len,
2573                                         KM_USER1);
2574                 }
2575                 ioff = btrfs_item_offset(leaf, item);
2576                 btrfs_set_item_offset(leaf, item, ioff - data_size);
2577         }
2578
2579         if (leaf->map_token) {
2580                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2581                 leaf->map_token = NULL;
2582         }
2583
2584         /* shift the data */
2585         memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2586                       data_end - data_size, btrfs_leaf_data(leaf) +
2587                       data_end, old_data - data_end);
2588
2589         data_end = old_data;
2590         old_size = btrfs_item_size_nr(leaf, slot);
2591         item = btrfs_item_nr(leaf, slot);
2592         btrfs_set_item_size(leaf, item, old_size + data_size);
2593         btrfs_mark_buffer_dirty(leaf);
2594
2595         ret = 0;
2596         if (btrfs_leaf_free_space(root, leaf) < 0) {
2597                 btrfs_print_leaf(root, leaf);
2598                 BUG();
2599         }
2600         return ret;
2601 }
2602
2603 /*
2604  * Given a key and some data, insert an item into the tree.
2605  * This does all the path init required, making room in the tree if needed.
2606  */
2607 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2608                             struct btrfs_root *root,
2609                             struct btrfs_path *path,
2610                             struct btrfs_key *cpu_key, u32 *data_size,
2611                             int nr)
2612 {
2613         struct extent_buffer *leaf;
2614         struct btrfs_item *item;
2615         int ret = 0;
2616         int slot;
2617         int slot_orig;
2618         int i;
2619         u32 nritems;
2620         u32 total_size = 0;
2621         u32 total_data = 0;
2622         unsigned int data_end;
2623         struct btrfs_disk_key disk_key;
2624
2625         for (i = 0; i < nr; i++) {
2626                 total_data += data_size[i];
2627         }
2628
2629         total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2630         ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2631         if (ret == 0) {
2632                 return -EEXIST;
2633         }
2634         if (ret < 0)
2635                 goto out;
2636
2637         slot_orig = path->slots[0];
2638         leaf = path->nodes[0];
2639
2640         nritems = btrfs_header_nritems(leaf);
2641         data_end = leaf_data_end(root, leaf);
2642
2643         if (btrfs_leaf_free_space(root, leaf) <
2644             sizeof(struct btrfs_item) + total_size) {
2645                 btrfs_print_leaf(root, leaf);
2646                 printk("not enough freespace need %u have %d\n",
2647                        total_size, btrfs_leaf_free_space(root, leaf));
2648                 BUG();
2649         }
2650
2651         slot = path->slots[0];
2652         BUG_ON(slot < 0);
2653
2654         if (slot != nritems) {
2655                 int i;
2656                 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2657
2658                 if (old_data < data_end) {
2659                         btrfs_print_leaf(root, leaf);
2660                         printk("slot %d old_data %d data_end %d\n",
2661                                slot, old_data, data_end);
2662                         BUG_ON(1);
2663                 }
2664                 /*
2665                  * item0..itemN ... dataN.offset..dataN.size .. data0.size
2666                  */
2667                 /* first correct the data pointers */
2668                 WARN_ON(leaf->map_token);
2669                 for (i = slot; i < nritems; i++) {
2670                         u32 ioff;
2671
2672                         item = btrfs_item_nr(leaf, i);
2673                         if (!leaf->map_token) {
2674                                 map_extent_buffer(leaf, (unsigned long)item,
2675                                         sizeof(struct btrfs_item),
2676                                         &leaf->map_token, &leaf->kaddr,
2677                                         &leaf->map_start, &leaf->map_len,
2678                                         KM_USER1);
2679                         }
2680
2681                         ioff = btrfs_item_offset(leaf, item);
2682                         btrfs_set_item_offset(leaf, item, ioff - total_data);
2683                 }
2684                 if (leaf->map_token) {
2685                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2686                         leaf->map_token = NULL;
2687                 }
2688
2689                 /* shift the items */
2690                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2691                               btrfs_item_nr_offset(slot),
2692                               (nritems - slot) * sizeof(struct btrfs_item));
2693
2694                 /* shift the data */
2695                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2696                               data_end - total_data, btrfs_leaf_data(leaf) +
2697                               data_end, old_data - data_end);
2698                 data_end = old_data;
2699         }
2700
2701         /* setup the item for the new data */
2702         for (i = 0; i < nr; i++) {
2703                 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2704                 btrfs_set_item_key(leaf, &disk_key, slot + i);
2705                 item = btrfs_item_nr(leaf, slot + i);
2706                 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2707                 data_end -= data_size[i];
2708                 btrfs_set_item_size(leaf, item, data_size[i]);
2709         }
2710         btrfs_set_header_nritems(leaf, nritems + nr);
2711         btrfs_mark_buffer_dirty(leaf);
2712
2713         ret = 0;
2714         if (slot == 0) {
2715                 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2716                 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2717         }
2718
2719         if (btrfs_leaf_free_space(root, leaf) < 0) {
2720                 btrfs_print_leaf(root, leaf);
2721                 BUG();
2722         }
2723 out:
2724         return ret;
2725 }
2726
2727 /*
2728  * Given a key and some data, insert an item into the tree.
2729  * This does all the path init required, making room in the tree if needed.
2730  */
2731 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2732                       *root, struct btrfs_key *cpu_key, void *data, u32
2733                       data_size)
2734 {
2735         int ret = 0;
2736         struct btrfs_path *path;
2737         struct extent_buffer *leaf;
2738         unsigned long ptr;
2739
2740         path = btrfs_alloc_path();
2741         BUG_ON(!path);
2742         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2743         if (!ret) {
2744                 leaf = path->nodes[0];
2745                 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2746                 write_extent_buffer(leaf, data, ptr, data_size);
2747                 btrfs_mark_buffer_dirty(leaf);
2748         }
2749         btrfs_free_path(path);
2750         return ret;
2751 }
2752
2753 /*
2754  * delete the pointer from a given node.
2755  *
2756  * If the delete empties a node, the node is removed from the tree,
2757  * continuing all the way the root if required.  The root is converted into
2758  * a leaf if all the nodes are emptied.
2759  */
2760 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2761                    struct btrfs_path *path, int level, int slot)
2762 {
2763         struct extent_buffer *parent = path->nodes[level];
2764         u32 nritems;
2765         int ret = 0;
2766         int wret;
2767
2768         nritems = btrfs_header_nritems(parent);
2769         if (slot != nritems -1) {
2770                 memmove_extent_buffer(parent,
2771                               btrfs_node_key_ptr_offset(slot),
2772                               btrfs_node_key_ptr_offset(slot + 1),
2773                               sizeof(struct btrfs_key_ptr) *
2774                               (nritems - slot - 1));
2775         }
2776         nritems--;
2777         btrfs_set_header_nritems(parent, nritems);
2778         if (nritems == 0 && parent == root->node) {
2779                 BUG_ON(btrfs_header_level(root->node) != 1);
2780                 /* just turn the root into a leaf and break */
2781                 btrfs_set_header_level(root->node, 0);
2782         } else if (slot == 0) {
2783                 struct btrfs_disk_key disk_key;
2784
2785                 btrfs_node_key(parent, &disk_key, 0);
2786                 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2787                 if (wret)
2788                         ret = wret;
2789         }
2790         btrfs_mark_buffer_dirty(parent);
2791         return ret;
2792 }
2793
2794 /*
2795  * delete the item at the leaf level in path.  If that empties
2796  * the leaf, remove it from the tree
2797  */
2798 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2799                     struct btrfs_path *path, int slot, int nr)
2800 {
2801         struct extent_buffer *leaf;
2802         struct btrfs_item *item;
2803         int last_off;
2804         int dsize = 0;
2805         int ret = 0;
2806         int wret;
2807         int i;
2808         u32 nritems;
2809
2810         leaf = path->nodes[0];
2811         last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2812
2813         for (i = 0; i < nr; i++)
2814                 dsize += btrfs_item_size_nr(leaf, slot + i);
2815
2816         nritems = btrfs_header_nritems(leaf);
2817
2818         if (slot + nr != nritems) {
2819                 int i;
2820                 int data_end = leaf_data_end(root, leaf);
2821
2822                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2823                               data_end + dsize,
2824                               btrfs_leaf_data(leaf) + data_end,
2825                               last_off - data_end);
2826
2827                 for (i = slot + nr; i < nritems; i++) {
2828                         u32 ioff;
2829
2830                         item = btrfs_item_nr(leaf, i);
2831                         if (!leaf->map_token) {
2832                                 map_extent_buffer(leaf, (unsigned long)item,
2833                                         sizeof(struct btrfs_item),
2834                                         &leaf->map_token, &leaf->kaddr,
2835                                         &leaf->map_start, &leaf->map_len,
2836                                         KM_USER1);
2837                         }
2838                         ioff = btrfs_item_offset(leaf, item);
2839                         btrfs_set_item_offset(leaf, item, ioff + dsize);
2840                 }
2841
2842                 if (leaf->map_token) {
2843                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2844                         leaf->map_token = NULL;
2845                 }
2846
2847                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2848                               btrfs_item_nr_offset(slot + nr),
2849                               sizeof(struct btrfs_item) *
2850                               (nritems - slot - nr));
2851         }
2852         btrfs_set_header_nritems(leaf, nritems - nr);
2853         nritems -= nr;
2854
2855         /* delete the leaf if we've emptied it */
2856         if (nritems == 0) {
2857                 if (leaf == root->node) {
2858                         btrfs_set_header_level(leaf, 0);
2859                 } else {
2860                         u64 root_gen = btrfs_header_generation(path->nodes[1]);
2861                         wret = del_ptr(trans, root, path, 1, path->slots[1]);
2862                         if (wret)
2863                                 ret = wret;
2864                         wret = btrfs_free_extent(trans, root,
2865                                          leaf->start, leaf->len,
2866                                          btrfs_header_owner(path->nodes[1]),
2867                                          root_gen, 0, 0, 1);
2868                         if (wret)
2869                                 ret = wret;
2870                 }
2871         } else {
2872                 int used = leaf_space_used(leaf, 0, nritems);
2873                 if (slot == 0) {
2874                         struct btrfs_disk_key disk_key;
2875
2876                         btrfs_item_key(leaf, &disk_key, 0);
2877                         wret = fixup_low_keys(trans, root, path,
2878                                               &disk_key, 1);
2879                         if (wret)
2880                                 ret = wret;
2881                 }
2882
2883                 /* delete the leaf if it is mostly empty */
2884                 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2885                         /* push_leaf_left fixes the path.
2886                          * make sure the path still points to our leaf
2887                          * for possible call to del_ptr below
2888                          */
2889                         slot = path->slots[1];
2890                         extent_buffer_get(leaf);
2891
2892                         wret = push_leaf_left(trans, root, path, 1, 1);
2893                         if (wret < 0 && wret != -ENOSPC)
2894                                 ret = wret;
2895
2896                         if (path->nodes[0] == leaf &&
2897                             btrfs_header_nritems(leaf)) {
2898                                 wret = push_leaf_right(trans, root, path, 1, 1);
2899                                 if (wret < 0 && wret != -ENOSPC)
2900                                         ret = wret;
2901                         }
2902
2903                         if (btrfs_header_nritems(leaf) == 0) {
2904                                 u64 root_gen;
2905                                 u64 bytenr = leaf->start;
2906                                 u32 blocksize = leaf->len;
2907
2908                                 root_gen = btrfs_header_generation(
2909                                                            path->nodes[1]);
2910
2911                                 wret = del_ptr(trans, root, path, 1, slot);
2912                                 if (wret)
2913                                         ret = wret;
2914
2915                                 free_extent_buffer(leaf);
2916                                 wret = btrfs_free_extent(trans, root, bytenr,
2917                                              blocksize,
2918                                              btrfs_header_owner(path->nodes[1]),
2919                                              root_gen, 0, 0, 1);
2920                                 if (wret)
2921                                         ret = wret;
2922                         } else {
2923                                 /* if we're still in the path, make sure
2924                                  * we're dirty.  Otherwise, one of the
2925                                  * push_leaf functions must have already
2926                                  * dirtied this buffer
2927                                  */
2928                                 if (path->nodes[0] == leaf)
2929                                         btrfs_mark_buffer_dirty(leaf);
2930                                 free_extent_buffer(leaf);
2931                         }
2932                 } else {
2933                         btrfs_mark_buffer_dirty(leaf);
2934                 }
2935         }
2936         return ret;
2937 }
2938
2939 /*
2940  * search the tree again to find a leaf with lesser keys
2941  * returns 0 if it found something or 1 if there are no lesser leaves.
2942  * returns < 0 on io errors.
2943  */
2944 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2945 {
2946         struct btrfs_key key;
2947         struct btrfs_disk_key found_key;
2948         int ret;
2949
2950         btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
2951
2952         if (key.offset > 0)
2953                 key.offset--;
2954         else if (key.type > 0)
2955                 key.type--;
2956         else if (key.objectid > 0)
2957                 key.objectid--;
2958         else
2959                 return 1;
2960
2961         btrfs_release_path(root, path);
2962         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2963         if (ret < 0)
2964                 return ret;
2965         btrfs_item_key(path->nodes[0], &found_key, 0);
2966         ret = comp_keys(&found_key, &key);
2967         if (ret < 0)
2968                 return 0;
2969         return 1;
2970 }
2971
2972 int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
2973                         struct btrfs_key *key, int lowest_level)
2974 {
2975         int level = lowest_level;
2976         int slot;
2977         struct extent_buffer *c;
2978
2979         while(level < BTRFS_MAX_LEVEL) {
2980                 if (!path->nodes[level])
2981                         return 1;
2982
2983                 slot = path->slots[level] + 1;
2984                 c = path->nodes[level];
2985                 if (slot >= btrfs_header_nritems(c)) {
2986                         level++;
2987                         if (level == BTRFS_MAX_LEVEL) {
2988                                 return 1;
2989                         }
2990                         continue;
2991                 }
2992                 if (level == 0)
2993                         btrfs_item_key_to_cpu(c, key, slot);
2994                 else
2995                         btrfs_node_key_to_cpu(c, key, slot);
2996                 return 0;
2997         }
2998         return 1;
2999 }
3000
3001 /*
3002  * search the tree again to find a leaf with greater keys
3003  * returns 0 if it found something or 1 if there are no greater leaves.
3004  * returns < 0 on io errors.
3005  */
3006 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
3007 {
3008         int slot;
3009         int level = 1;
3010         struct extent_buffer *c;
3011         struct extent_buffer *next = NULL;
3012         struct btrfs_key key;
3013         u32 nritems;
3014         int ret;
3015
3016         nritems = btrfs_header_nritems(path->nodes[0]);
3017         if (nritems == 0) {
3018                 return 1;
3019         }
3020
3021         btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
3022
3023         btrfs_release_path(root, path);
3024         path->keep_locks = 1;
3025         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3026         path->keep_locks = 0;
3027
3028         if (ret < 0)
3029                 return ret;
3030
3031         nritems = btrfs_header_nritems(path->nodes[0]);
3032         /*
3033          * by releasing the path above we dropped all our locks.  A balance
3034          * could have added more items next to the key that used to be
3035          * at the very end of the block.  So, check again here and
3036          * advance the path if there are now more items available.
3037          */
3038         if (nritems > 0 && path->slots[0] < nritems - 1) {
3039                 path->slots[0]++;
3040                 goto done;
3041         }
3042
3043         while(level < BTRFS_MAX_LEVEL) {
3044                 if (!path->nodes[level])
3045                         return 1;
3046
3047                 slot = path->slots[level] + 1;
3048                 c = path->nodes[level];
3049                 if (slot >= btrfs_header_nritems(c)) {
3050                         level++;
3051                         if (level == BTRFS_MAX_LEVEL) {
3052                                 return 1;
3053                         }
3054                         continue;
3055                 }
3056
3057                 if (next) {
3058                         btrfs_tree_unlock(next);
3059                         free_extent_buffer(next);
3060                 }
3061
3062                 if (level == 1 && path->locks[1] && path->reada)
3063                         reada_for_search(root, path, level, slot, 0);
3064
3065                 next = read_node_slot(root, c, slot);
3066                 if (!path->skip_locking) {
3067                         WARN_ON(!btrfs_tree_locked(c));
3068                         btrfs_tree_lock(next);
3069                 }
3070                 break;
3071         }
3072         path->slots[level] = slot;
3073         while(1) {
3074                 level--;
3075                 c = path->nodes[level];
3076                 if (path->locks[level])
3077                         btrfs_tree_unlock(c);
3078                 free_extent_buffer(c);
3079                 path->nodes[level] = next;
3080                 path->slots[level] = 0;
3081                 if (!path->skip_locking)
3082                         path->locks[level] = 1;
3083                 if (!level)
3084                         break;
3085                 if (level == 1 && path->locks[1] && path->reada)
3086                         reada_for_search(root, path, level, slot, 0);
3087                 next = read_node_slot(root, next, 0);
3088                 if (!path->skip_locking) {
3089                         WARN_ON(!btrfs_tree_locked(path->nodes[level]));
3090                         btrfs_tree_lock(next);
3091                 }
3092         }
3093 done:
3094         unlock_up(path, 0, 1);
3095         return 0;
3096 }
3097
3098 int btrfs_previous_item(struct btrfs_root *root,
3099                         struct btrfs_path *path, u64 min_objectid,
3100                         int type)
3101 {
3102         struct btrfs_key found_key;
3103         struct extent_buffer *leaf;
3104         int ret;
3105
3106         while(1) {
3107                 if (path->slots[0] == 0) {
3108                         ret = btrfs_prev_leaf(root, path);
3109                         if (ret != 0)
3110                                 return ret;
3111                 } else {
3112                         path->slots[0]--;
3113                 }
3114                 leaf = path->nodes[0];
3115                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3116                 if (found_key.type == type)
3117                         return 0;
3118         }
3119         return 1;
3120 }
3121