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 noinline btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
  64 {
  65         int i;
  66
  67         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
  68                 p->slots[i] = 0;
  69                 if (!p->nodes[i])
  70                         continue;
  71                 if (p->locks[i]) {
  72                         btrfs_tree_unlock(p->nodes[i]);
  73                         p->locks[i] = 0;
  74                 }
  75                 free_extent_buffer(p->nodes[i]);
  76                 p->nodes[i] = NULL;
  77         }
  78 }
  79
  80 struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
  81 {
  82         struct extent_buffer *eb;
  83         spin_lock(&root->node_lock);
  84         eb = root->node;
  85         extent_buffer_get(eb);
  86         spin_unlock(&root->node_lock);
  87         return eb;
  88 }
  89
  90 struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
  91 {
  92         struct extent_buffer *eb;
  93
  94         while(1) {
  95                 eb = btrfs_root_node(root);
  96                 btrfs_tree_lock(eb);
  97
  98                 spin_lock(&root->node_lock);
  99                 if (eb == root->node) {
 100                         spin_unlock(&root->node_lock);
 101                         break;
 102                 }
 103                 spin_unlock(&root->node_lock);
 104
 105                 btrfs_tree_unlock(eb);
 106                 free_extent_buffer(eb);
 107         }
 108         return eb;
 109 }
 110
 111 static void add_root_to_dirty_list(struct btrfs_root *root)
 112 {
 113         if (root->track_dirty && list_empty(&root->dirty_list)) {
 114                 list_add(&root->dirty_list,
 115                          &root->fs_info->dirty_cowonly_roots);
 116         }
 117 }
 118
 119 int btrfs_copy_root(struct btrfs_trans_handle *trans,
 120                       struct btrfs_root *root,
 121                       struct extent_buffer *buf,
 122                       struct extent_buffer **cow_ret, u64 new_root_objectid)
 123 {
 124         struct extent_buffer *cow;
 125         u32 nritems;
 126         int ret = 0;
 127         int level;
 128         struct btrfs_root *new_root;
 129
 130         new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
 131         if (!new_root)
 132                 return -ENOMEM;
 133
 134         memcpy(new_root, root, sizeof(*new_root));
 135         new_root->root_key.objectid = new_root_objectid;
 136
 137         WARN_ON(root->ref_cows && trans->transid !=
 138                 root->fs_info->running_transaction->transid);
 139         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 140
 141         level = btrfs_header_level(buf);
 142         nritems = btrfs_header_nritems(buf);
 143
 144         cow = btrfs_alloc_free_block(trans, new_root, buf->len, 0,
 145                                      new_root_objectid, trans->transid,
 146                                      level, buf->start, 0);
 147         if (IS_ERR(cow)) {
 148                 kfree(new_root);
 149                 return PTR_ERR(cow);
 150         }
 151
 152         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 153         btrfs_set_header_bytenr(cow, cow->start);
 154         btrfs_set_header_generation(cow, trans->transid);
 155         btrfs_set_header_owner(cow, new_root_objectid);
 156         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 157
 158         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 159         ret = btrfs_inc_ref(trans, new_root, buf, cow, NULL);
 160         kfree(new_root);
 161
 162         if (ret)
 163                 return ret;
 164
 165         btrfs_mark_buffer_dirty(cow);
 166         *cow_ret = cow;
 167         return 0;
 168 }
 169
 170 int noinline __btrfs_cow_block(struct btrfs_trans_handle *trans,
 171                              struct btrfs_root *root,
 172                              struct extent_buffer *buf,
 173                              struct extent_buffer *parent, int parent_slot,
 174                              struct extent_buffer **cow_ret,
 175                              u64 search_start, u64 empty_size,
 176                              u64 prealloc_dest)
 177 {
 178         u64 parent_start;
 179         struct extent_buffer *cow;
 180         u32 nritems;
 181         int ret = 0;
 182         int different_trans = 0;
 183         int level;
 184         int unlock_orig = 0;
 185
 186         if (*cow_ret == buf)
 187                 unlock_orig = 1;
 188
 189         WARN_ON(!btrfs_tree_locked(buf));
 190
 191         if (parent)
 192                 parent_start = parent->start;
 193         else
 194                 parent_start = 0;
 195
 196         WARN_ON(root->ref_cows && trans->transid !=
 197                 root->fs_info->running_transaction->transid);
 198         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 199
 200         level = btrfs_header_level(buf);
 201         nritems = btrfs_header_nritems(buf);
 202
 203         if (prealloc_dest) {
 204                 struct btrfs_key ins;
 205
 206                 ins.objectid = prealloc_dest;
 207                 ins.offset = buf->len;
 208                 ins.type = BTRFS_EXTENT_ITEM_KEY;
 209
 210                 ret = btrfs_alloc_reserved_extent(trans, root, parent_start,
 211                                                   root->root_key.objectid,
 212                                                   trans->transid, level, 0,
 213                                                   &ins);
 214                 BUG_ON(ret);
 215                 cow = btrfs_init_new_buffer(trans, root, prealloc_dest,
 216                                             buf->len);
 217         } else {
 218                 cow = btrfs_alloc_free_block(trans, root, buf->len,
 219                                              parent_start,
 220                                              root->root_key.objectid,
 221                                              trans->transid, level,
 222                                              search_start, empty_size);
 223         }
 224         if (IS_ERR(cow))
 225                 return PTR_ERR(cow);
 226
 227         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 228         btrfs_set_header_bytenr(cow, cow->start);
 229         btrfs_set_header_generation(cow, trans->transid);
 230         btrfs_set_header_owner(cow, root->root_key.objectid);
 231         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 232
 233         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 234         if (btrfs_header_generation(buf) != trans->transid) {
 235                 u32 nr_extents;
 236                 different_trans = 1;
 237                 ret = btrfs_inc_ref(trans, root, buf, cow, &nr_extents);
 238                 if (ret)
 239                         return ret;
 240
 241                 ret = btrfs_cache_ref(trans, root, buf, nr_extents);
 242                 WARN_ON(ret);
 243         } else {
 244                 ret = btrfs_update_ref(trans, root, buf, cow, 0, nritems);
 245                 if (ret)
 246                         return ret;
 247                 clean_tree_block(trans, root, buf);
 248         }
 249
 250         if (buf == root->node) {
 251                 WARN_ON(parent && parent != buf);
 252
 253                 spin_lock(&root->node_lock);
 254                 root->node = cow;
 255                 extent_buffer_get(cow);
 256                 spin_unlock(&root->node_lock);
 257
 258                 if (buf != root->commit_root) {
 259                         btrfs_free_extent(trans, root, buf->start,
 260                                           buf->len, buf->start,
 261                                           root->root_key.objectid,
 262                                           btrfs_header_generation(buf),
 263                                           0, 0, 1);
 264                 }
 265                 free_extent_buffer(buf);
 266                 add_root_to_dirty_list(root);
 267         } else {
 268                 btrfs_set_node_blockptr(parent, parent_slot,
 269                                         cow->start);
 270                 WARN_ON(trans->transid == 0);
 271                 btrfs_set_node_ptr_generation(parent, parent_slot,
 272                                               trans->transid);
 273                 btrfs_mark_buffer_dirty(parent);
 274                 WARN_ON(btrfs_header_generation(parent) != trans->transid);
 275                 btrfs_free_extent(trans, root, buf->start, buf->len,
 276                                   parent_start, btrfs_header_owner(parent),
 277                                   btrfs_header_generation(parent), 0, 0, 1);
 278         }
 279         if (unlock_orig)
 280                 btrfs_tree_unlock(buf);
 281         free_extent_buffer(buf);
 282         btrfs_mark_buffer_dirty(cow);
 283         *cow_ret = cow;
 284         return 0;
 285 }
 286
 287 int noinline btrfs_cow_block(struct btrfs_trans_handle *trans,
 288                     struct btrfs_root *root, struct extent_buffer *buf,
 289                     struct extent_buffer *parent, int parent_slot,
 290                     struct extent_buffer **cow_ret, u64 prealloc_dest)
 291 {
 292         u64 search_start;
 293         u64 header_trans;
 294         int ret;
 295
 296         if (trans->transaction != root->fs_info->running_transaction) {
 297                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 298                        root->fs_info->running_transaction->transid);
 299                 WARN_ON(1);
 300         }
 301         if (trans->transid != root->fs_info->generation) {
 302                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 303                        root->fs_info->generation);
 304                 WARN_ON(1);
 305         }
 306
 307         header_trans = btrfs_header_generation(buf);
 308         spin_lock(&root->fs_info->hash_lock);
 309         if (header_trans == trans->transid &&
 310             !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
 311                 *cow_ret = buf;
 312                 spin_unlock(&root->fs_info->hash_lock);
 313                 WARN_ON(prealloc_dest);
 314                 return 0;
 315         }
 316         spin_unlock(&root->fs_info->hash_lock);
 317         search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
 318         ret = __btrfs_cow_block(trans, root, buf, parent,
 319                                  parent_slot, cow_ret, search_start, 0,
 320                                  prealloc_dest);
 321         return ret;
 322 }
 323
 324 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
 325 {
 326         if (blocknr < other && other - (blocknr + blocksize) < 32768)
 327                 return 1;
 328         if (blocknr > other && blocknr - (other + blocksize) < 32768)
 329                 return 1;
 330         return 0;
 331 }
 332
 333 /*
 334  * compare two keys in a memcmp fashion
 335  */
 336 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
 337 {
 338         struct btrfs_key k1;
 339
 340         btrfs_disk_key_to_cpu(&k1, disk);
 341
 342         if (k1.objectid > k2->objectid)
 343                 return 1;
 344         if (k1.objectid < k2->objectid)
 345                 return -1;
 346         if (k1.type > k2->type)
 347                 return 1;
 348         if (k1.type < k2->type)
 349                 return -1;
 350         if (k1.offset > k2->offset)
 351                 return 1;
 352         if (k1.offset < k2->offset)
 353                 return -1;
 354         return 0;
 355 }
 356
 357
 358 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 359                        struct btrfs_root *root, struct extent_buffer *parent,
 360                        int start_slot, int cache_only, u64 *last_ret,
 361                        struct btrfs_key *progress)
 362 {
 363         struct extent_buffer *cur;
 364         u64 blocknr;
 365         u64 gen;
 366         u64 search_start = *last_ret;
 367         u64 last_block = 0;
 368         u64 other;
 369         u32 parent_nritems;
 370         int end_slot;
 371         int i;
 372         int err = 0;
 373         int parent_level;
 374         int uptodate;
 375         u32 blocksize;
 376         int progress_passed = 0;
 377         struct btrfs_disk_key disk_key;
 378
 379         parent_level = btrfs_header_level(parent);
 380         if (cache_only && parent_level != 1)
 381                 return 0;
 382
 383         if (trans->transaction != root->fs_info->running_transaction) {
 384                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 385                        root->fs_info->running_transaction->transid);
 386                 WARN_ON(1);
 387         }
 388         if (trans->transid != root->fs_info->generation) {
 389                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 390                        root->fs_info->generation);
 391                 WARN_ON(1);
 392         }
 393
 394         parent_nritems = btrfs_header_nritems(parent);
 395         blocksize = btrfs_level_size(root, parent_level - 1);
 396         end_slot = parent_nritems;
 397
 398         if (parent_nritems == 1)
 399                 return 0;
 400
 401         for (i = start_slot; i < end_slot; i++) {
 402                 int close = 1;
 403
 404                 if (!parent->map_token) {
 405                         map_extent_buffer(parent,
 406                                         btrfs_node_key_ptr_offset(i),
 407                                         sizeof(struct btrfs_key_ptr),
 408                                         &parent->map_token, &parent->kaddr,
 409                                         &parent->map_start, &parent->map_len,
 410                                         KM_USER1);
 411                 }
 412                 btrfs_node_key(parent, &disk_key, i);
 413                 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
 414                         continue;
 415
 416                 progress_passed = 1;
 417                 blocknr = btrfs_node_blockptr(parent, i);
 418                 gen = btrfs_node_ptr_generation(parent, i);
 419                 if (last_block == 0)
 420                         last_block = blocknr;
 421
 422                 if (i > 0) {
 423                         other = btrfs_node_blockptr(parent, i - 1);
 424                         close = close_blocks(blocknr, other, blocksize);
 425                 }
 426                 if (!close && i < end_slot - 2) {
 427                         other = btrfs_node_blockptr(parent, i + 1);
 428                         close = close_blocks(blocknr, other, blocksize);
 429                 }
 430                 if (close) {
 431                         last_block = blocknr;
 432                         continue;
 433                 }
 434                 if (parent->map_token) {
 435                         unmap_extent_buffer(parent, parent->map_token,
 436                                             KM_USER1);
 437                         parent->map_token = NULL;
 438                 }
 439
 440                 cur = btrfs_find_tree_block(root, blocknr, blocksize);
 441                 if (cur)
 442                         uptodate = btrfs_buffer_uptodate(cur, gen);
 443                 else
 444                         uptodate = 0;
 445                 if (!cur || !uptodate) {
 446                         if (cache_only) {
 447                                 free_extent_buffer(cur);
 448                                 continue;
 449                         }
 450                         if (!cur) {
 451                                 cur = read_tree_block(root, blocknr,
 452                                                          blocksize, gen);
 453                         } else if (!uptodate) {
 454                                 btrfs_read_buffer(cur, gen);
 455                         }
 456                 }
 457                 if (search_start == 0)
 458                         search_start = last_block;
 459
 460                 btrfs_tree_lock(cur);
 461                 err = __btrfs_cow_block(trans, root, cur, parent, i,
 462                                         &cur, search_start,
 463                                         min(16 * blocksize,
 464                                             (end_slot - i) * blocksize), 0);
 465                 if (err) {
 466                         btrfs_tree_unlock(cur);
 467                         free_extent_buffer(cur);
 468                         break;
 469                 }
 470                 search_start = cur->start;
 471                 last_block = cur->start;
 472                 *last_ret = search_start;
 473                 btrfs_tree_unlock(cur);
 474                 free_extent_buffer(cur);
 475         }
 476         if (parent->map_token) {
 477                 unmap_extent_buffer(parent, parent->map_token,
 478                                     KM_USER1);
 479                 parent->map_token = NULL;
 480         }
 481         return err;
 482 }
 483
 484 /*
 485  * The leaf data grows from end-to-front in the node.
 486  * this returns the address of the start of the last item,
 487  * which is the stop of the leaf data stack
 488  */
 489 static inline unsigned int leaf_data_end(struct btrfs_root *root,
 490                                          struct extent_buffer *leaf)
 491 {
 492         u32 nr = btrfs_header_nritems(leaf);
 493         if (nr == 0)
 494                 return BTRFS_LEAF_DATA_SIZE(root);
 495         return btrfs_item_offset_nr(leaf, nr - 1);
 496 }
 497
 498 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
 499                       int level)
 500 {
 501         struct extent_buffer *parent = NULL;
 502         struct extent_buffer *node = path->nodes[level];
 503         struct btrfs_disk_key parent_key;
 504         struct btrfs_disk_key node_key;
 505         int parent_slot;
 506         int slot;
 507         struct btrfs_key cpukey;
 508         u32 nritems = btrfs_header_nritems(node);
 509
 510         if (path->nodes[level + 1])
 511                 parent = path->nodes[level + 1];
 512
 513         slot = path->slots[level];
 514         BUG_ON(nritems == 0);
 515         if (parent) {
 516                 parent_slot = path->slots[level + 1];
 517                 btrfs_node_key(parent, &parent_key, parent_slot);
 518                 btrfs_node_key(node, &node_key, 0);
 519                 BUG_ON(memcmp(&parent_key, &node_key,
 520                               sizeof(struct btrfs_disk_key)));
 521                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 522                        btrfs_header_bytenr(node));
 523         }
 524         BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
 525         if (slot != 0) {
 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         if (slot < nritems - 1) {
 531                 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
 532                 btrfs_node_key(node, &node_key, slot);
 533                 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
 534         }
 535         return 0;
 536 }
 537
 538 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
 539                       int level)
 540 {
 541         struct extent_buffer *leaf = path->nodes[level];
 542         struct extent_buffer *parent = NULL;
 543         int parent_slot;
 544         struct btrfs_key cpukey;
 545         struct btrfs_disk_key parent_key;
 546         struct btrfs_disk_key leaf_key;
 547         int slot = path->slots[0];
 548
 549         u32 nritems = btrfs_header_nritems(leaf);
 550
 551         if (path->nodes[level + 1])
 552                 parent = path->nodes[level + 1];
 553
 554         if (nritems == 0)
 555                 return 0;
 556
 557         if (parent) {
 558                 parent_slot = path->slots[level + 1];
 559                 btrfs_node_key(parent, &parent_key, parent_slot);
 560                 btrfs_item_key(leaf, &leaf_key, 0);
 561
 562                 BUG_ON(memcmp(&parent_key, &leaf_key,
 563                        sizeof(struct btrfs_disk_key)));
 564                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 565                        btrfs_header_bytenr(leaf));
 566         }
 567 #if 0
 568         for (i = 0; nritems > 1 && i < nritems - 2; i++) {
 569                 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
 570                 btrfs_item_key(leaf, &leaf_key, i);
 571                 if (comp_keys(&leaf_key, &cpukey) >= 0) {
 572                         btrfs_print_leaf(root, leaf);
 573                         printk("slot %d offset bad key\n", i);
 574                         BUG_ON(1);
 575                 }
 576                 if (btrfs_item_offset_nr(leaf, i) !=
 577                         btrfs_item_end_nr(leaf, i + 1)) {
 578                         btrfs_print_leaf(root, leaf);
 579                         printk("slot %d offset bad\n", i);
 580                         BUG_ON(1);
 581                 }
 582                 if (i == 0) {
 583                         if (btrfs_item_offset_nr(leaf, i) +
 584                                btrfs_item_size_nr(leaf, i) !=
 585                                BTRFS_LEAF_DATA_SIZE(root)) {
 586                                 btrfs_print_leaf(root, leaf);
 587                                 printk("slot %d first offset bad\n", i);
 588                                 BUG_ON(1);
 589                         }
 590                 }
 591         }
 592         if (nritems > 0) {
 593                 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
 594                                 btrfs_print_leaf(root, leaf);
 595                                 printk("slot %d bad size \n", nritems - 1);
 596                                 BUG_ON(1);
 597                 }
 598         }
 599 #endif
 600         if (slot != 0 && slot < nritems - 1) {
 601                 btrfs_item_key(leaf, &leaf_key, slot);
 602                 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
 603                 if (comp_keys(&leaf_key, &cpukey) <= 0) {
 604                         btrfs_print_leaf(root, leaf);
 605                         printk("slot %d offset bad key\n", slot);
 606                         BUG_ON(1);
 607                 }
 608                 if (btrfs_item_offset_nr(leaf, slot - 1) !=
 609                        btrfs_item_end_nr(leaf, slot)) {
 610                         btrfs_print_leaf(root, leaf);
 611                         printk("slot %d offset bad\n", slot);
 612                         BUG_ON(1);
 613                 }
 614         }
 615         if (slot < nritems - 1) {
 616                 btrfs_item_key(leaf, &leaf_key, slot);
 617                 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
 618                 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
 619                 if (btrfs_item_offset_nr(leaf, slot) !=
 620                         btrfs_item_end_nr(leaf, slot + 1)) {
 621                         btrfs_print_leaf(root, leaf);
 622                         printk("slot %d offset bad\n", slot);
 623                         BUG_ON(1);
 624                 }
 625         }
 626         BUG_ON(btrfs_item_offset_nr(leaf, 0) +
 627                btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
 628         return 0;
 629 }
 630
 631 static int noinline check_block(struct btrfs_root *root,
 632                                 struct btrfs_path *path, int level)
 633 {
 634         u64 found_start;
 635         return 0;
 636         if (btrfs_header_level(path->nodes[level]) != level)
 637             printk("warning: bad level %Lu wanted %d found %d\n",
 638                    path->nodes[level]->start, level,
 639                    btrfs_header_level(path->nodes[level]));
 640         found_start = btrfs_header_bytenr(path->nodes[level]);
 641         if (found_start != path->nodes[level]->start) {
 642             printk("warning: bad bytentr %Lu found %Lu\n",
 643                    path->nodes[level]->start, found_start);
 644         }
 645 #if 0
 646         struct extent_buffer *buf = path->nodes[level];
 647
 648         if (memcmp_extent_buffer(buf, root->fs_info->fsid,
 649                                  (unsigned long)btrfs_header_fsid(buf),
 650                                  BTRFS_FSID_SIZE)) {
 651                 printk("warning bad block %Lu\n", buf->start);
 652                 return 1;
 653         }
 654 #endif
 655         if (level == 0)
 656                 return check_leaf(root, path, level);
 657         return check_node(root, path, level);
 658 }
 659
 660 /*
 661  * search for key in the extent_buffer.  The items start at offset p,
 662  * and they are item_size apart.  There are 'max' items in p.
 663  *
 664  * the slot in the array is returned via slot, and it points to
 665  * the place where you would insert key if it is not found in
 666  * the array.
 667  *
 668  * slot may point to max if the key is bigger than all of the keys
 669  */
 670 static noinline int generic_bin_search(struct extent_buffer *eb,
 671                                        unsigned long p,
 672                                        int item_size, struct btrfs_key *key,
 673                                        int max, int *slot)
 674 {
 675         int low = 0;
 676         int high = max;
 677         int mid;
 678         int ret;
 679         struct btrfs_disk_key *tmp = NULL;
 680         struct btrfs_disk_key unaligned;
 681         unsigned long offset;
 682         char *map_token = NULL;
 683         char *kaddr = NULL;
 684         unsigned long map_start = 0;
 685         unsigned long map_len = 0;
 686         int err;
 687
 688         while(low < high) {
 689                 mid = (low + high) / 2;
 690                 offset = p + mid * item_size;
 691
 692                 if (!map_token || offset < map_start ||
 693                     (offset + sizeof(struct btrfs_disk_key)) >
 694                     map_start + map_len) {
 695                         if (map_token) {
 696                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 697                                 map_token = NULL;
 698                         }
 699                         err = map_extent_buffer(eb, offset,
 700                                                 sizeof(struct btrfs_disk_key),
 701                                                 &map_token, &kaddr,
 702                                                 &map_start, &map_len, KM_USER0);
 703
 704                         if (!err) {
 705                                 tmp = (struct btrfs_disk_key *)(kaddr + offset -
 706                                                         map_start);
 707                         } else {
 708                                 read_extent_buffer(eb, &unaligned,
 709                                                    offset, sizeof(unaligned));
 710                                 tmp = &unaligned;
 711                         }
 712
 713                 } else {
 714                         tmp = (struct btrfs_disk_key *)(kaddr + offset -
 715                                                         map_start);
 716                 }
 717                 ret = comp_keys(tmp, key);
 718
 719                 if (ret < 0)
 720                         low = mid + 1;
 721                 else if (ret > 0)
 722                         high = mid;
 723                 else {
 724                         *slot = mid;
 725                         if (map_token)
 726                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 727                         return 0;
 728                 }
 729         }
 730         *slot = low;
 731         if (map_token)
 732                 unmap_extent_buffer(eb, map_token, KM_USER0);
 733         return 1;
 734 }
 735
 736 /*
 737  * simple bin_search frontend that does the right thing for
 738  * leaves vs nodes
 739  */
 740 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
 741                       int level, int *slot)
 742 {
 743         if (level == 0) {
 744                 return generic_bin_search(eb,
 745                                           offsetof(struct btrfs_leaf, items),
 746                                           sizeof(struct btrfs_item),
 747                                           key, btrfs_header_nritems(eb),
 748                                           slot);
 749         } else {
 750                 return generic_bin_search(eb,
 751                                           offsetof(struct btrfs_node, ptrs),
 752                                           sizeof(struct btrfs_key_ptr),
 753                                           key, btrfs_header_nritems(eb),
 754                                           slot);
 755         }
 756         return -1;
 757 }
 758
 759 static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
 760                                    struct extent_buffer *parent, int slot)
 761 {
 762         int level = btrfs_header_level(parent);
 763         if (slot < 0)
 764                 return NULL;
 765         if (slot >= btrfs_header_nritems(parent))
 766                 return NULL;
 767
 768         BUG_ON(level == 0);
 769
 770         return read_tree_block(root, btrfs_node_blockptr(parent, slot),
 771                        btrfs_level_size(root, level - 1),
 772                        btrfs_node_ptr_generation(parent, slot));
 773 }
 774
 775 static noinline int balance_level(struct btrfs_trans_handle *trans,
 776                          struct btrfs_root *root,
 777                          struct btrfs_path *path, int level)
 778 {
 779         struct extent_buffer *right = NULL;
 780         struct extent_buffer *mid;
 781         struct extent_buffer *left = NULL;
 782         struct extent_buffer *parent = NULL;
 783         int ret = 0;
 784         int wret;
 785         int pslot;
 786         int orig_slot = path->slots[level];
 787         int err_on_enospc = 0;
 788         u64 orig_ptr;
 789
 790         if (level == 0)
 791                 return 0;
 792
 793         mid = path->nodes[level];
 794         WARN_ON(!path->locks[level]);
 795         WARN_ON(btrfs_header_generation(mid) != trans->transid);
 796
 797         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 798
 799         if (level < BTRFS_MAX_LEVEL - 1)
 800                 parent = path->nodes[level + 1];
 801         pslot = path->slots[level + 1];
 802
 803         /*
 804          * deal with the case where there is only one pointer in the root
 805          * by promoting the node below to a root
 806          */
 807         if (!parent) {
 808                 struct extent_buffer *child;
 809
 810                 if (btrfs_header_nritems(mid) != 1)
 811                         return 0;
 812
 813                 /* promote the child to a root */
 814                 child = read_node_slot(root, mid, 0);
 815                 btrfs_tree_lock(child);
 816                 BUG_ON(!child);
 817                 ret = btrfs_cow_block(trans, root, child, mid, 0, &child, 0);
 818                 BUG_ON(ret);
 819
 820                 spin_lock(&root->node_lock);
 821                 root->node = child;
 822                 spin_unlock(&root->node_lock);
 823
 824                 ret = btrfs_update_extent_ref(trans, root, child->start,
 825                                               mid->start, child->start,
 826                                               root->root_key.objectid,
 827                                               trans->transid, level - 1, 0);
 828                 BUG_ON(ret);
 829
 830                 add_root_to_dirty_list(root);
 831                 btrfs_tree_unlock(child);
 832                 path->locks[level] = 0;
 833                 path->nodes[level] = NULL;
 834                 clean_tree_block(trans, root, mid);
 835                 btrfs_tree_unlock(mid);
 836                 /* once for the path */
 837                 free_extent_buffer(mid);
 838                 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
 839                                         mid->start, root->root_key.objectid,
 840                                         btrfs_header_generation(mid), 0, 0, 1);
 841                 /* once for the root ptr */
 842                 free_extent_buffer(mid);
 843                 return ret;
 844         }
 845         if (btrfs_header_nritems(mid) >
 846             BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
 847                 return 0;
 848
 849         if (btrfs_header_nritems(mid) < 2)
 850                 err_on_enospc = 1;
 851
 852         left = read_node_slot(root, parent, pslot - 1);
 853         if (left) {
 854                 btrfs_tree_lock(left);
 855                 wret = btrfs_cow_block(trans, root, left,
 856                                        parent, pslot - 1, &left, 0);
 857                 if (wret) {
 858                         ret = wret;
 859                         goto enospc;
 860                 }
 861         }
 862         right = read_node_slot(root, parent, pslot + 1);
 863         if (right) {
 864                 btrfs_tree_lock(right);
 865                 wret = btrfs_cow_block(trans, root, right,
 866                                        parent, pslot + 1, &right, 0);
 867                 if (wret) {
 868                         ret = wret;
 869                         goto enospc;
 870                 }
 871         }
 872
 873         /* first, try to make some room in the middle buffer */
 874         if (left) {
 875                 orig_slot += btrfs_header_nritems(left);
 876                 wret = push_node_left(trans, root, left, mid, 1);
 877                 if (wret < 0)
 878                         ret = wret;
 879                 if (btrfs_header_nritems(mid) < 2)
 880                         err_on_enospc = 1;
 881         }
 882
 883         /*
 884          * then try to empty the right most buffer into the middle
 885          */
 886         if (right) {
 887                 wret = push_node_left(trans, root, mid, right, 1);
 888                 if (wret < 0 && wret != -ENOSPC)
 889                         ret = wret;
 890                 if (btrfs_header_nritems(right) == 0) {
 891                         u64 bytenr = right->start;
 892                         u64 generation = btrfs_header_generation(parent);
 893                         u32 blocksize = right->len;
 894
 895                         clean_tree_block(trans, root, right);
 896                         btrfs_tree_unlock(right);
 897                         free_extent_buffer(right);
 898                         right = NULL;
 899                         wret = del_ptr(trans, root, path, level + 1, pslot +
 900                                        1);
 901                         if (wret)
 902                                 ret = wret;
 903                         wret = btrfs_free_extent(trans, root, bytenr,
 904                                                  blocksize, parent->start,
 905                                                  btrfs_header_owner(parent),
 906                                                  generation, 0, 0, 1);
 907                         if (wret)
 908                                 ret = wret;
 909                 } else {
 910                         struct btrfs_disk_key right_key;
 911                         btrfs_node_key(right, &right_key, 0);
 912                         btrfs_set_node_key(parent, &right_key, pslot + 1);
 913                         btrfs_mark_buffer_dirty(parent);
 914                 }
 915         }
 916         if (btrfs_header_nritems(mid) == 1) {
 917                 /*
 918                  * we're not allowed to leave a node with one item in the
 919                  * tree during a delete.  A deletion from lower in the tree
 920                  * could try to delete the only pointer in this node.
 921                  * So, pull some keys from the left.
 922                  * There has to be a left pointer at this point because
 923                  * otherwise we would have pulled some pointers from the
 924                  * right
 925                  */
 926                 BUG_ON(!left);
 927                 wret = balance_node_right(trans, root, mid, left);
 928                 if (wret < 0) {
 929                         ret = wret;
 930                         goto enospc;
 931                 }
 932                 if (wret == 1) {
 933                         wret = push_node_left(trans, root, left, mid, 1);
 934                         if (wret < 0)
 935                                 ret = wret;
 936                 }
 937                 BUG_ON(wret == 1);
 938         }
 939         if (btrfs_header_nritems(mid) == 0) {
 940                 /* we've managed to empty the middle node, drop it */
 941                 u64 root_gen = btrfs_header_generation(parent);
 942                 u64 bytenr = mid->start;
 943                 u32 blocksize = mid->len;
 944
 945                 clean_tree_block(trans, root, mid);
 946                 btrfs_tree_unlock(mid);
 947                 free_extent_buffer(mid);
 948                 mid = NULL;
 949                 wret = del_ptr(trans, root, path, level + 1, pslot);
 950                 if (wret)
 951                         ret = wret;
 952                 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
 953                                          parent->start,
 954                                          btrfs_header_owner(parent),
 955                                          root_gen, 0, 0, 1);
 956                 if (wret)
 957                         ret = wret;
 958         } else {
 959                 /* update the parent key to reflect our changes */
 960                 struct btrfs_disk_key mid_key;
 961                 btrfs_node_key(mid, &mid_key, 0);
 962                 btrfs_set_node_key(parent, &mid_key, pslot);
 963                 btrfs_mark_buffer_dirty(parent);
 964         }
 965
 966         /* update the path */
 967         if (left) {
 968                 if (btrfs_header_nritems(left) > orig_slot) {
 969                         extent_buffer_get(left);
 970                         /* left was locked after cow */
 971                         path->nodes[level] = left;
 972                         path->slots[level + 1] -= 1;
 973                         path->slots[level] = orig_slot;
 974                         if (mid) {
 975                                 btrfs_tree_unlock(mid);
 976                                 free_extent_buffer(mid);
 977                         }
 978                 } else {
 979                         orig_slot -= btrfs_header_nritems(left);
 980                         path->slots[level] = orig_slot;
 981                 }
 982         }
 983         /* double check we haven't messed things up */
 984         check_block(root, path, level);
 985         if (orig_ptr !=
 986             btrfs_node_blockptr(path->nodes[level], path->slots[level]))
 987                 BUG();
 988 enospc:
 989         if (right) {
 990                 btrfs_tree_unlock(right);
 991                 free_extent_buffer(right);
 992         }
 993         if (left) {
 994                 if (path->nodes[level] != left)
 995                         btrfs_tree_unlock(left);
 996                 free_extent_buffer(left);
 997         }
 998         return ret;
 999 }
1000
1001 /* returns zero if the push worked, non-zero otherwise */
1002 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
1003                                           struct btrfs_root *root,
1004                                           struct btrfs_path *path, int level)
1005 {
1006         struct extent_buffer *right = NULL;
1007         struct extent_buffer *mid;
1008         struct extent_buffer *left = NULL;
1009         struct extent_buffer *parent = NULL;
1010         int ret = 0;
1011         int wret;
1012         int pslot;
1013         int orig_slot = path->slots[level];
1014         u64 orig_ptr;
1015
1016         if (level == 0)
1017                 return 1;
1018
1019         mid = path->nodes[level];
1020         WARN_ON(btrfs_header_generation(mid) != trans->transid);
1021         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
1022
1023         if (level < BTRFS_MAX_LEVEL - 1)
1024                 parent = path->nodes[level + 1];
1025         pslot = path->slots[level + 1];
1026
1027         if (!parent)
1028                 return 1;
1029
1030         left = read_node_slot(root, parent, pslot - 1);
1031
1032         /* first, try to make some room in the middle buffer */
1033         if (left) {
1034                 u32 left_nr;
1035
1036                 btrfs_tree_lock(left);
1037                 left_nr = btrfs_header_nritems(left);
1038                 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1039                         wret = 1;
1040                 } else {
1041                         ret = btrfs_cow_block(trans, root, left, parent,
1042                                               pslot - 1, &left, 0);
1043                         if (ret)
1044                                 wret = 1;
1045                         else {
1046                                 wret = push_node_left(trans, root,
1047                                                       left, mid, 0);
1048                         }
1049                 }
1050                 if (wret < 0)
1051                         ret = wret;
1052                 if (wret == 0) {
1053                         struct btrfs_disk_key disk_key;
1054                         orig_slot += left_nr;
1055                         btrfs_node_key(mid, &disk_key, 0);
1056                         btrfs_set_node_key(parent, &disk_key, pslot);
1057                         btrfs_mark_buffer_dirty(parent);
1058                         if (btrfs_header_nritems(left) > orig_slot) {
1059                                 path->nodes[level] = left;
1060                                 path->slots[level + 1] -= 1;
1061                                 path->slots[level] = orig_slot;
1062                                 btrfs_tree_unlock(mid);
1063                                 free_extent_buffer(mid);
1064                         } else {
1065                                 orig_slot -=
1066                                         btrfs_header_nritems(left);
1067                                 path->slots[level] = orig_slot;
1068                                 btrfs_tree_unlock(left);
1069                                 free_extent_buffer(left);
1070                         }
1071                         return 0;
1072                 }
1073                 btrfs_tree_unlock(left);
1074                 free_extent_buffer(left);
1075         }
1076         right = read_node_slot(root, parent, pslot + 1);
1077
1078         /*
1079          * then try to empty the right most buffer into the middle
1080          */
1081         if (right) {
1082                 u32 right_nr;
1083                 btrfs_tree_lock(right);
1084                 right_nr = btrfs_header_nritems(right);
1085                 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1086                         wret = 1;
1087                 } else {
1088                         ret = btrfs_cow_block(trans, root, right,
1089                                               parent, pslot + 1,
1090                                               &right, 0);
1091                         if (ret)
1092                                 wret = 1;
1093                         else {
1094                                 wret = balance_node_right(trans, root,
1095                                                           right, mid);
1096                         }
1097                 }
1098                 if (wret < 0)
1099                         ret = wret;
1100                 if (wret == 0) {
1101                         struct btrfs_disk_key disk_key;
1102
1103                         btrfs_node_key(right, &disk_key, 0);
1104                         btrfs_set_node_key(parent, &disk_key, pslot + 1);
1105                         btrfs_mark_buffer_dirty(parent);
1106
1107                         if (btrfs_header_nritems(mid) <= orig_slot) {
1108                                 path->nodes[level] = right;
1109                                 path->slots[level + 1] += 1;
1110                                 path->slots[level] = orig_slot -
1111                                         btrfs_header_nritems(mid);
1112                                 btrfs_tree_unlock(mid);
1113                                 free_extent_buffer(mid);
1114                         } else {
1115                                 btrfs_tree_unlock(right);
1116                                 free_extent_buffer(right);
1117                         }
1118                         return 0;
1119                 }
1120                 btrfs_tree_unlock(right);
1121                 free_extent_buffer(right);
1122         }
1123         return 1;
1124 }
1125
1126 /*
1127  * readahead one full node of leaves
1128  */
1129 static noinline void reada_for_search(struct btrfs_root *root,
1130                                       struct btrfs_path *path,
1131                                       int level, int slot, u64 objectid)
1132 {
1133         struct extent_buffer *node;
1134         struct btrfs_disk_key disk_key;
1135         u32 nritems;
1136         u64 search;
1137         u64 lowest_read;
1138         u64 highest_read;
1139         u64 nread = 0;
1140         int direction = path->reada;
1141         struct extent_buffer *eb;
1142         u32 nr;
1143         u32 blocksize;
1144         u32 nscan = 0;
1145
1146         if (level != 1)
1147                 return;
1148
1149         if (!path->nodes[level])
1150                 return;
1151
1152         node = path->nodes[level];
1153
1154         search = btrfs_node_blockptr(node, slot);
1155         blocksize = btrfs_level_size(root, level - 1);
1156         eb = btrfs_find_tree_block(root, search, blocksize);
1157         if (eb) {
1158                 free_extent_buffer(eb);
1159                 return;
1160         }
1161
1162         highest_read = search;
1163         lowest_read = search;
1164
1165         nritems = btrfs_header_nritems(node);
1166         nr = slot;
1167         while(1) {
1168                 if (direction < 0) {
1169                         if (nr == 0)
1170                                 break;
1171                         nr--;
1172                 } else if (direction > 0) {
1173                         nr++;
1174                         if (nr >= nritems)
1175                                 break;
1176                 }
1177                 if (path->reada < 0 && objectid) {
1178                         btrfs_node_key(node, &disk_key, nr);
1179                         if (btrfs_disk_key_objectid(&disk_key) != objectid)
1180                                 break;
1181                 }
1182                 search = btrfs_node_blockptr(node, nr);
1183                 if ((search >= lowest_read && search <= highest_read) ||
1184                     (search < lowest_read && lowest_read - search <= 32768) ||
1185                     (search > highest_read && search - highest_read <= 32768)) {
1186                         readahead_tree_block(root, search, blocksize,
1187                                      btrfs_node_ptr_generation(node, nr));
1188                         nread += blocksize;
1189                 }
1190                 nscan++;
1191                 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1192                         break;
1193                 if(nread > (1024 * 1024) || nscan > 128)
1194                         break;
1195
1196                 if (search < lowest_read)
1197                         lowest_read = search;
1198                 if (search > highest_read)
1199                         highest_read = search;
1200         }
1201 }
1202
1203 static noinline void unlock_up(struct btrfs_path *path, int level,
1204                                int lowest_unlock)
1205 {
1206         int i;
1207         int skip_level = level;
1208         int no_skips = 0;
1209         struct extent_buffer *t;
1210
1211         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1212                 if (!path->nodes[i])
1213                         break;
1214                 if (!path->locks[i])
1215                         break;
1216                 if (!no_skips && path->slots[i] == 0) {
1217                         skip_level = i + 1;
1218                         continue;
1219                 }
1220                 if (!no_skips && path->keep_locks) {
1221                         u32 nritems;
1222                         t = path->nodes[i];
1223                         nritems = btrfs_header_nritems(t);
1224                         if (nritems < 1 || path->slots[i] >= nritems - 1) {
1225                                 skip_level = i + 1;
1226                                 continue;
1227                         }
1228                 }
1229                 if (skip_level < i && i >= lowest_unlock)
1230                         no_skips = 1;
1231
1232                 t = path->nodes[i];
1233                 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
1234                         btrfs_tree_unlock(t);
1235                         path->locks[i] = 0;
1236                 }
1237         }
1238 }
1239
1240 /*
1241  * look for key in the tree.  path is filled in with nodes along the way
1242  * if key is found, we return zero and you can find the item in the leaf
1243  * level of the path (level 0)
1244  *
1245  * If the key isn't found, the path points to the slot where it should
1246  * be inserted, and 1 is returned.  If there are other errors during the
1247  * search a negative error number is returned.
1248  *
1249  * if ins_len > 0, nodes and leaves will be split as we walk down the
1250  * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
1251  * possible)
1252  */
1253 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1254                       *root, struct btrfs_key *key, struct btrfs_path *p, int
1255                       ins_len, int cow)
1256 {
1257         struct extent_buffer *b;
1258         struct extent_buffer *tmp;
1259         int slot;
1260         int ret;
1261         int level;
1262         int should_reada = p->reada;
1263         int lowest_unlock = 1;
1264         int blocksize;
1265         u8 lowest_level = 0;
1266         u64 blocknr;
1267         u64 gen;
1268         struct btrfs_key prealloc_block;
1269
1270         lowest_level = p->lowest_level;
1271         WARN_ON(lowest_level && ins_len);
1272         WARN_ON(p->nodes[0] != NULL);
1273         WARN_ON(cow && root == root->fs_info->extent_root &&
1274                 !mutex_is_locked(&root->fs_info->alloc_mutex));
1275         if (ins_len < 0)
1276                 lowest_unlock = 2;
1277
1278         prealloc_block.objectid = 0;
1279
1280 again:
1281         if (p->skip_locking)
1282                 b = btrfs_root_node(root);
1283         else
1284                 b = btrfs_lock_root_node(root);
1285
1286         while (b) {
1287                 level = btrfs_header_level(b);
1288
1289                 /*
1290                  * setup the path here so we can release it under lock
1291                  * contention with the cow code
1292                  */
1293                 p->nodes[level] = b;
1294                 if (!p->skip_locking)
1295                         p->locks[level] = 1;
1296
1297                 if (cow) {
1298                         int wret;
1299
1300                         /* is a cow on this block not required */
1301                         spin_lock(&root->fs_info->hash_lock);
1302                         if (btrfs_header_generation(b) == trans->transid &&
1303                             !btrfs_header_flag(b, BTRFS_HEADER_FLAG_WRITTEN)) {
1304                                 spin_unlock(&root->fs_info->hash_lock);
1305                                 goto cow_done;
1306                         }
1307                         spin_unlock(&root->fs_info->hash_lock);
1308
1309                         /* ok, we have to cow, is our old prealloc the right
1310                          * size?
1311                          */
1312                         if (prealloc_block.objectid &&
1313                             prealloc_block.offset != b->len) {
1314                                 btrfs_free_reserved_extent(root,
1315                                            prealloc_block.objectid,
1316                                            prealloc_block.offset);
1317                                 prealloc_block.objectid = 0;
1318                         }
1319
1320                         /*
1321                          * for higher level blocks, try not to allocate blocks
1322                          * with the block and the parent locks held.
1323                          */
1324                         if (level > 1 && !prealloc_block.objectid &&
1325                             btrfs_path_lock_waiting(p, level)) {
1326                                 u32 size = b->len;
1327                                 u64 hint = b->start;
1328
1329                                 btrfs_release_path(root, p);
1330                                 ret = btrfs_reserve_extent(trans, root,
1331                                                            size, size, 0,
1332                                                            hint, (u64)-1,
1333                                                            &prealloc_block, 0);
1334                                 BUG_ON(ret);
1335                                 goto again;
1336                         }
1337
1338                         wret = btrfs_cow_block(trans, root, b,
1339                                                p->nodes[level + 1],
1340                                                p->slots[level + 1],
1341                                                &b, prealloc_block.objectid);
1342                         prealloc_block.objectid = 0;
1343                         if (wret) {
1344                                 free_extent_buffer(b);
1345                                 ret = wret;
1346                                 goto done;
1347                         }
1348                 }
1349 cow_done:
1350                 BUG_ON(!cow && ins_len);
1351                 if (level != btrfs_header_level(b))
1352                         WARN_ON(1);
1353                 level = btrfs_header_level(b);
1354
1355                 p->nodes[level] = b;
1356                 if (!p->skip_locking)
1357                         p->locks[level] = 1;
1358
1359                 ret = check_block(root, p, level);
1360                 if (ret) {
1361                         ret = -1;
1362                         goto done;
1363                 }
1364
1365                 ret = bin_search(b, key, level, &slot);
1366                 if (level != 0) {
1367                         if (ret && slot > 0)
1368                                 slot -= 1;
1369                         p->slots[level] = slot;
1370                         if (ins_len > 0 && btrfs_header_nritems(b) >=
1371                             BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1372                                 int sret = split_node(trans, root, p, level);
1373                                 BUG_ON(sret > 0);
1374                                 if (sret) {
1375                                         ret = sret;
1376                                         goto done;
1377                                 }
1378                                 b = p->nodes[level];
1379                                 slot = p->slots[level];
1380                         } else if (ins_len < 0) {
1381                                 int sret = balance_level(trans, root, p,
1382                                                          level);
1383                                 if (sret) {
1384                                         ret = sret;
1385                                         goto done;
1386                                 }
1387                                 b = p->nodes[level];
1388                                 if (!b) {
1389                                         btrfs_release_path(NULL, p);
1390                                         goto again;
1391                                 }
1392                                 slot = p->slots[level];
1393                                 BUG_ON(btrfs_header_nritems(b) == 1);
1394                         }
1395                         unlock_up(p, level, lowest_unlock);
1396
1397                         /* this is only true while dropping a snapshot */
1398                         if (level == lowest_level) {
1399                                 break;
1400                         }
1401
1402                         blocknr = btrfs_node_blockptr(b, slot);
1403                         gen = btrfs_node_ptr_generation(b, slot);
1404                         blocksize = btrfs_level_size(root, level - 1);
1405
1406                         tmp = btrfs_find_tree_block(root, blocknr, blocksize);
1407                         if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
1408                                 b = tmp;
1409                         } else {
1410                                 /*
1411                                  * reduce lock contention at high levels
1412                                  * of the btree by dropping locks before
1413                                  * we read.
1414                                  */
1415                                 if (level > 1) {
1416                                         btrfs_release_path(NULL, p);
1417                                         if (tmp)
1418                                                 free_extent_buffer(tmp);
1419                                         if (should_reada)
1420                                                 reada_for_search(root, p,
1421                                                                  level, slot,
1422                                                                  key->objectid);
1423
1424                                         tmp = read_tree_block(root, blocknr,
1425                                                          blocksize, gen);
1426                                         if (tmp)
1427                                                 free_extent_buffer(tmp);
1428                                         goto again;
1429                                 } else {
1430                                         if (tmp)
1431                                                 free_extent_buffer(tmp);
1432                                         if (should_reada)
1433                                                 reada_for_search(root, p,
1434                                                                  level, slot,
1435                                                                  key->objectid);
1436                                         b = read_node_slot(root, b, slot);
1437                                 }
1438                         }
1439                         if (!p->skip_locking)
1440                                 btrfs_tree_lock(b);
1441                 } else {
1442                         p->slots[level] = slot;
1443                         if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1444                             sizeof(struct btrfs_item) + ins_len) {
1445                                 int sret = split_leaf(trans, root, key,
1446                                                       p, ins_len, ret == 0);
1447                                 BUG_ON(sret > 0);
1448                                 if (sret) {
1449                                         ret = sret;
1450                                         goto done;
1451                                 }
1452                         }
1453                         unlock_up(p, level, lowest_unlock);
1454                         goto done;
1455                 }
1456         }
1457         ret = 1;
1458 done:
1459         if (prealloc_block.objectid) {
1460                 btrfs_free_reserved_extent(root,
1461                            prealloc_block.objectid,
1462                            prealloc_block.offset);
1463         }
1464
1465         return ret;
1466 }
1467
1468 /*
1469  * adjust the pointers going up the tree, starting at level
1470  * making sure the right key of each node is points to 'key'.
1471  * This is used after shifting pointers to the left, so it stops
1472  * fixing up pointers when a given leaf/node is not in slot 0 of the
1473  * higher levels
1474  *
1475  * If this fails to write a tree block, it returns -1, but continues
1476  * fixing up the blocks in ram so the tree is consistent.
1477  */
1478 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1479                           struct btrfs_root *root, struct btrfs_path *path,
1480                           struct btrfs_disk_key *key, int level)
1481 {
1482         int i;
1483         int ret = 0;
1484         struct extent_buffer *t;
1485
1486         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1487                 int tslot = path->slots[i];
1488                 if (!path->nodes[i])
1489                         break;
1490                 t = path->nodes[i];
1491                 btrfs_set_node_key(t, key, tslot);
1492                 btrfs_mark_buffer_dirty(path->nodes[i]);
1493                 if (tslot != 0)
1494                         break;
1495         }
1496         return ret;
1497 }
1498
1499 /*
1500  * update item key.
1501  *
1502  * This function isn't completely safe. It's the caller's responsibility
1503  * that the new key won't break the order
1504  */
1505 int btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
1506                             struct btrfs_root *root, struct btrfs_path *path,
1507                             struct btrfs_key *new_key)
1508 {
1509         struct btrfs_disk_key disk_key;
1510         struct extent_buffer *eb;
1511         int slot;
1512
1513         eb = path->nodes[0];
1514         slot = path->slots[0];
1515         if (slot > 0) {
1516                 btrfs_item_key(eb, &disk_key, slot - 1);
1517                 if (comp_keys(&disk_key, new_key) >= 0)
1518                         return -1;
1519         }
1520         if (slot < btrfs_header_nritems(eb) - 1) {
1521                 btrfs_item_key(eb, &disk_key, slot + 1);
1522                 if (comp_keys(&disk_key, new_key) <= 0)
1523                         return -1;
1524         }
1525
1526         btrfs_cpu_key_to_disk(&disk_key, new_key);
1527         btrfs_set_item_key(eb, &disk_key, slot);
1528         btrfs_mark_buffer_dirty(eb);
1529         if (slot == 0)
1530                 fixup_low_keys(trans, root, path, &disk_key, 1);
1531         return 0;
1532 }
1533
1534 /*
1535  * try to push data from one node into the next node left in the
1536  * tree.
1537  *
1538  * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1539  * error, and > 0 if there was no room in the left hand block.
1540  */
1541 static int push_node_left(struct btrfs_trans_handle *trans,
1542                           struct btrfs_root *root, struct extent_buffer *dst,
1543                           struct extent_buffer *src, int empty)
1544 {
1545         int push_items = 0;
1546         int src_nritems;
1547         int dst_nritems;
1548         int ret = 0;
1549
1550         src_nritems = btrfs_header_nritems(src);
1551         dst_nritems = btrfs_header_nritems(dst);
1552         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1553         WARN_ON(btrfs_header_generation(src) != trans->transid);
1554         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1555
1556         if (!empty && src_nritems <= 8)
1557                 return 1;
1558
1559         if (push_items <= 0) {
1560                 return 1;
1561         }
1562
1563         if (empty) {
1564                 push_items = min(src_nritems, push_items);
1565                 if (push_items < src_nritems) {
1566                         /* leave at least 8 pointers in the node if
1567                          * we aren't going to empty it
1568                          */
1569                         if (src_nritems - push_items < 8) {
1570                                 if (push_items <= 8)
1571                                         return 1;
1572                                 push_items -= 8;
1573                         }
1574                 }
1575         } else
1576                 push_items = min(src_nritems - 8, push_items);
1577
1578         copy_extent_buffer(dst, src,
1579                            btrfs_node_key_ptr_offset(dst_nritems),
1580                            btrfs_node_key_ptr_offset(0),
1581                            push_items * sizeof(struct btrfs_key_ptr));
1582
1583         if (push_items < src_nritems) {
1584                 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1585                                       btrfs_node_key_ptr_offset(push_items),
1586                                       (src_nritems - push_items) *
1587                                       sizeof(struct btrfs_key_ptr));
1588         }
1589         btrfs_set_header_nritems(src, src_nritems - push_items);
1590         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1591         btrfs_mark_buffer_dirty(src);
1592         btrfs_mark_buffer_dirty(dst);
1593
1594         ret = btrfs_update_ref(trans, root, src, dst, dst_nritems, push_items);
1595         BUG_ON(ret);
1596
1597         return ret;
1598 }
1599
1600 /*
1601  * try to push data from one node into the next node right in the
1602  * tree.
1603  *
1604  * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1605  * error, and > 0 if there was no room in the right hand block.
1606  *
1607  * this will  only push up to 1/2 the contents of the left node over
1608  */
1609 static int balance_node_right(struct btrfs_trans_handle *trans,
1610                               struct btrfs_root *root,
1611                               struct extent_buffer *dst,
1612                               struct extent_buffer *src)
1613 {
1614         int push_items = 0;
1615         int max_push;
1616         int src_nritems;
1617         int dst_nritems;
1618         int ret = 0;
1619
1620         WARN_ON(btrfs_header_generation(src) != trans->transid);
1621         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1622
1623         src_nritems = btrfs_header_nritems(src);
1624         dst_nritems = btrfs_header_nritems(dst);
1625         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1626         if (push_items <= 0) {
1627                 return 1;
1628         }
1629
1630         if (src_nritems < 4) {
1631                 return 1;
1632         }
1633
1634         max_push = src_nritems / 2 + 1;
1635         /* don't try to empty the node */
1636         if (max_push >= src_nritems) {
1637                 return 1;
1638         }
1639
1640         if (max_push < push_items)
1641                 push_items = max_push;
1642
1643         memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1644                                       btrfs_node_key_ptr_offset(0),
1645                                       (dst_nritems) *
1646                                       sizeof(struct btrfs_key_ptr));
1647
1648         copy_extent_buffer(dst, src,
1649                            btrfs_node_key_ptr_offset(0),
1650                            btrfs_node_key_ptr_offset(src_nritems - push_items),
1651                            push_items * sizeof(struct btrfs_key_ptr));
1652
1653         btrfs_set_header_nritems(src, src_nritems - push_items);
1654         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1655
1656         btrfs_mark_buffer_dirty(src);
1657         btrfs_mark_buffer_dirty(dst);
1658
1659         ret = btrfs_update_ref(trans, root, src, dst, 0, push_items);
1660         BUG_ON(ret);
1661
1662         return ret;
1663 }
1664
1665 /*
1666  * helper function to insert a new root level in the tree.
1667  * A new node is allocated, and a single item is inserted to
1668  * point to the existing root
1669  *
1670  * returns zero on success or < 0 on failure.
1671  */
1672 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1673                            struct btrfs_root *root,
1674                            struct btrfs_path *path, int level)
1675 {
1676         u64 lower_gen;
1677         struct extent_buffer *lower;
1678         struct extent_buffer *c;
1679         struct extent_buffer *old;
1680         struct btrfs_disk_key lower_key;
1681         int ret;
1682
1683         BUG_ON(path->nodes[level]);
1684         BUG_ON(path->nodes[level-1] != root->node);
1685
1686         lower = path->nodes[level-1];
1687         if (level == 1)
1688                 btrfs_item_key(lower, &lower_key, 0);
1689         else
1690                 btrfs_node_key(lower, &lower_key, 0);
1691
1692         c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
1693                                    root->root_key.objectid, trans->transid,
1694                                    level, root->node->start, 0);
1695         if (IS_ERR(c))
1696                 return PTR_ERR(c);
1697
1698         memset_extent_buffer(c, 0, 0, root->nodesize);
1699         btrfs_set_header_nritems(c, 1);
1700         btrfs_set_header_level(c, level);
1701         btrfs_set_header_bytenr(c, c->start);
1702         btrfs_set_header_generation(c, trans->transid);
1703         btrfs_set_header_owner(c, root->root_key.objectid);
1704
1705         write_extent_buffer(c, root->fs_info->fsid,
1706                             (unsigned long)btrfs_header_fsid(c),
1707                             BTRFS_FSID_SIZE);
1708
1709         write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1710                             (unsigned long)btrfs_header_chunk_tree_uuid(c),
1711                             BTRFS_UUID_SIZE);
1712
1713         btrfs_set_node_key(c, &lower_key, 0);
1714         btrfs_set_node_blockptr(c, 0, lower->start);
1715         lower_gen = btrfs_header_generation(lower);
1716         WARN_ON(lower_gen != trans->transid);
1717
1718         btrfs_set_node_ptr_generation(c, 0, lower_gen);
1719
1720         btrfs_mark_buffer_dirty(c);
1721
1722         spin_lock(&root->node_lock);
1723         old = root->node;
1724         root->node = c;
1725         spin_unlock(&root->node_lock);
1726
1727         ret = btrfs_update_extent_ref(trans, root, lower->start,
1728                                       lower->start, c->start,
1729                                       root->root_key.objectid,
1730                                       trans->transid, level - 1, 0);
1731         BUG_ON(ret);
1732
1733         /* the super has an extra ref to root->node */
1734         free_extent_buffer(old);
1735
1736         add_root_to_dirty_list(root);
1737         extent_buffer_get(c);
1738         path->nodes[level] = c;
1739         path->locks[level] = 1;
1740         path->slots[level] = 0;
1741         return 0;
1742 }
1743
1744 /*
1745  * worker function to insert a single pointer in a node.
1746  * the node should have enough room for the pointer already
1747  *
1748  * slot and level indicate where you want the key to go, and
1749  * blocknr is the block the key points to.
1750  *
1751  * returns zero on success and < 0 on any error
1752  */
1753 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1754                       *root, struct btrfs_path *path, struct btrfs_disk_key
1755                       *key, u64 bytenr, int slot, int level)
1756 {
1757         struct extent_buffer *lower;
1758         int nritems;
1759
1760         BUG_ON(!path->nodes[level]);
1761         lower = path->nodes[level];
1762         nritems = btrfs_header_nritems(lower);
1763         if (slot > nritems)
1764                 BUG();
1765         if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1766                 BUG();
1767         if (slot != nritems) {
1768                 memmove_extent_buffer(lower,
1769                               btrfs_node_key_ptr_offset(slot + 1),
1770                               btrfs_node_key_ptr_offset(slot),
1771                               (nritems - slot) * sizeof(struct btrfs_key_ptr));
1772         }
1773         btrfs_set_node_key(lower, key, slot);
1774         btrfs_set_node_blockptr(lower, slot, bytenr);
1775         WARN_ON(trans->transid == 0);
1776         btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1777         btrfs_set_header_nritems(lower, nritems + 1);
1778         btrfs_mark_buffer_dirty(lower);
1779         return 0;
1780 }
1781
1782 /*
1783  * split the node at the specified level in path in two.
1784  * The path is corrected to point to the appropriate node after the split
1785  *
1786  * Before splitting this tries to make some room in the node by pushing
1787  * left and right, if either one works, it returns right away.
1788  *
1789  * returns 0 on success and < 0 on failure
1790  */
1791 static noinline int split_node(struct btrfs_trans_handle *trans,
1792                                struct btrfs_root *root,
1793                                struct btrfs_path *path, int level)
1794 {
1795         struct extent_buffer *c;
1796         struct extent_buffer *split;
1797         struct btrfs_disk_key disk_key;
1798         int mid;
1799         int ret;
1800         int wret;
1801         u32 c_nritems;
1802
1803         c = path->nodes[level];
1804         WARN_ON(btrfs_header_generation(c) != trans->transid);
1805         if (c == root->node) {
1806                 /* trying to split the root, lets make a new one */
1807                 ret = insert_new_root(trans, root, path, level + 1);
1808                 if (ret)
1809                         return ret;
1810         } else {
1811                 ret = push_nodes_for_insert(trans, root, path, level);
1812                 c = path->nodes[level];
1813                 if (!ret && btrfs_header_nritems(c) <
1814                     BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1815                         return 0;
1816                 if (ret < 0)
1817                         return ret;
1818         }
1819
1820         c_nritems = btrfs_header_nritems(c);
1821
1822         split = btrfs_alloc_free_block(trans, root, root->nodesize,
1823                                         path->nodes[level + 1]->start,
1824                                         root->root_key.objectid,
1825                                         trans->transid, level, c->start, 0);
1826         if (IS_ERR(split))
1827                 return PTR_ERR(split);
1828
1829         btrfs_set_header_flags(split, btrfs_header_flags(c));
1830         btrfs_set_header_level(split, btrfs_header_level(c));
1831         btrfs_set_header_bytenr(split, split->start);
1832         btrfs_set_header_generation(split, trans->transid);
1833         btrfs_set_header_owner(split, root->root_key.objectid);
1834         btrfs_set_header_flags(split, 0);
1835         write_extent_buffer(split, root->fs_info->fsid,
1836                             (unsigned long)btrfs_header_fsid(split),
1837                             BTRFS_FSID_SIZE);
1838         write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1839                             (unsigned long)btrfs_header_chunk_tree_uuid(split),
1840                             BTRFS_UUID_SIZE);
1841
1842         mid = (c_nritems + 1) / 2;
1843
1844         copy_extent_buffer(split, c,
1845                            btrfs_node_key_ptr_offset(0),
1846                            btrfs_node_key_ptr_offset(mid),
1847                            (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1848         btrfs_set_header_nritems(split, c_nritems - mid);
1849         btrfs_set_header_nritems(c, mid);
1850         ret = 0;
1851
1852         btrfs_mark_buffer_dirty(c);
1853         btrfs_mark_buffer_dirty(split);
1854
1855         btrfs_node_key(split, &disk_key, 0);
1856         wret = insert_ptr(trans, root, path, &disk_key, split->start,
1857                           path->slots[level + 1] + 1,
1858                           level + 1);
1859         if (wret)
1860                 ret = wret;
1861
1862         ret = btrfs_update_ref(trans, root, c, split, 0, c_nritems - mid);
1863         BUG_ON(ret);
1864
1865         if (path->slots[level] >= mid) {
1866                 path->slots[level] -= mid;
1867                 btrfs_tree_unlock(c);
1868                 free_extent_buffer(c);
1869                 path->nodes[level] = split;
1870                 path->slots[level + 1] += 1;
1871         } else {
1872                 btrfs_tree_unlock(split);
1873                 free_extent_buffer(split);
1874         }
1875         return ret;
1876 }
1877
1878 /*
1879  * how many bytes are required to store the items in a leaf.  start
1880  * and nr indicate which items in the leaf to check.  This totals up the
1881  * space used both by the item structs and the item data
1882  */
1883 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1884 {
1885         int data_len;
1886         int nritems = btrfs_header_nritems(l);
1887         int end = min(nritems, start + nr) - 1;
1888
1889         if (!nr)
1890                 return 0;
1891         data_len = btrfs_item_end_nr(l, start);
1892         data_len = data_len - btrfs_item_offset_nr(l, end);
1893         data_len += sizeof(struct btrfs_item) * nr;
1894         WARN_ON(data_len < 0);
1895         return data_len;
1896 }
1897
1898 /*
1899  * The space between the end of the leaf items and
1900  * the start of the leaf data.  IOW, how much room
1901  * the leaf has left for both items and data
1902  */
1903 int noinline btrfs_leaf_free_space(struct btrfs_root *root,
1904                                    struct extent_buffer *leaf)
1905 {
1906         int nritems = btrfs_header_nritems(leaf);
1907         int ret;
1908         ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1909         if (ret < 0) {
1910                 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1911                        ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1912                        leaf_space_used(leaf, 0, nritems), nritems);
1913         }
1914         return ret;
1915 }
1916
1917 /*
1918  * push some data in the path leaf to the right, trying to free up at
1919  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1920  *
1921  * returns 1 if the push failed because the other node didn't have enough
1922  * room, 0 if everything worked out and < 0 if there were major errors.
1923  */
1924 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1925                            *root, struct btrfs_path *path, int data_size,
1926                            int empty)
1927 {
1928         struct extent_buffer *left = path->nodes[0];
1929         struct extent_buffer *right;
1930         struct extent_buffer *upper;
1931         struct btrfs_disk_key disk_key;
1932         int slot;
1933         u32 i;
1934         int free_space;
1935         int push_space = 0;
1936         int push_items = 0;
1937         struct btrfs_item *item;
1938         u32 left_nritems;
1939         u32 nr;
1940         u32 right_nritems;
1941         u32 data_end;
1942         u32 this_item_size;
1943         int ret;
1944
1945         slot = path->slots[1];
1946         if (!path->nodes[1]) {
1947                 return 1;
1948         }
1949         upper = path->nodes[1];
1950         if (slot >= btrfs_header_nritems(upper) - 1)
1951                 return 1;
1952
1953         WARN_ON(!btrfs_tree_locked(path->nodes[1]));
1954
1955         right = read_node_slot(root, upper, slot + 1);
1956         btrfs_tree_lock(right);
1957         free_space = btrfs_leaf_free_space(root, right);
1958         if (free_space < data_size + sizeof(struct btrfs_item))
1959                 goto out_unlock;
1960
1961         /* cow and double check */
1962         ret = btrfs_cow_block(trans, root, right, upper,
1963                               slot + 1, &right, 0);
1964         if (ret)
1965                 goto out_unlock;
1966
1967         free_space = btrfs_leaf_free_space(root, right);
1968         if (free_space < data_size + sizeof(struct btrfs_item))
1969                 goto out_unlock;
1970
1971         left_nritems = btrfs_header_nritems(left);
1972         if (left_nritems == 0)
1973                 goto out_unlock;
1974
1975         if (empty)
1976                 nr = 0;
1977         else
1978                 nr = 1;
1979
1980         if (path->slots[0] >= left_nritems)
1981                 push_space += data_size + sizeof(*item);
1982
1983         i = left_nritems - 1;
1984         while (i >= nr) {
1985                 item = btrfs_item_nr(left, i);
1986
1987                 if (!empty && push_items > 0) {
1988                         if (path->slots[0] > i)
1989                                 break;
1990                         if (path->slots[0] == i) {
1991                                 int space = btrfs_leaf_free_space(root, left);
1992                                 if (space + push_space * 2 > free_space)
1993                                         break;
1994                         }
1995                 }
1996
1997                 if (path->slots[0] == i)
1998                         push_space += data_size + sizeof(*item);
1999
2000                 if (!left->map_token) {
2001                         map_extent_buffer(left, (unsigned long)item,
2002                                         sizeof(struct btrfs_item),
2003                                         &left->map_token, &left->kaddr,
2004                                         &left->map_start, &left->map_len,
2005                                         KM_USER1);
2006                 }
2007
2008                 this_item_size = btrfs_item_size(left, item);
2009                 if (this_item_size + sizeof(*item) + push_space > free_space)
2010                         break;
2011
2012                 push_items++;
2013                 push_space += this_item_size + sizeof(*item);
2014                 if (i == 0)
2015                         break;
2016                 i--;
2017         }
2018         if (left->map_token) {
2019                 unmap_extent_buffer(left, left->map_token, KM_USER1);
2020                 left->map_token = NULL;
2021         }
2022
2023         if (push_items == 0)
2024                 goto out_unlock;
2025
2026         if (!empty && push_items == left_nritems)
2027                 WARN_ON(1);
2028
2029         /* push left to right */
2030         right_nritems = btrfs_header_nritems(right);
2031
2032         push_space = btrfs_item_end_nr(left, left_nritems - push_items);
2033         push_space -= leaf_data_end(root, left);
2034
2035         /* make room in the right data area */
2036         data_end = leaf_data_end(root, right);
2037         memmove_extent_buffer(right,
2038                               btrfs_leaf_data(right) + data_end - push_space,
2039                               btrfs_leaf_data(right) + data_end,
2040                               BTRFS_LEAF_DATA_SIZE(root) - data_end);
2041
2042         /* copy from the left data area */
2043         copy_extent_buffer(right, left, btrfs_leaf_data(right) +
2044                      BTRFS_LEAF_DATA_SIZE(root) - push_space,
2045                      btrfs_leaf_data(left) + leaf_data_end(root, left),
2046                      push_space);
2047
2048         memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
2049                               btrfs_item_nr_offset(0),
2050                               right_nritems * sizeof(struct btrfs_item));
2051
2052         /* copy the items from left to right */
2053         copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
2054                    btrfs_item_nr_offset(left_nritems - push_items),
2055                    push_items * sizeof(struct btrfs_item));
2056
2057         /* update the item pointers */
2058         right_nritems += push_items;
2059         btrfs_set_header_nritems(right, right_nritems);
2060         push_space = BTRFS_LEAF_DATA_SIZE(root);
2061         for (i = 0; i < right_nritems; i++) {
2062                 item = btrfs_item_nr(right, i);
2063                 if (!right->map_token) {
2064                         map_extent_buffer(right, (unsigned long)item,
2065                                         sizeof(struct btrfs_item),
2066                                         &right->map_token, &right->kaddr,
2067                                         &right->map_start, &right->map_len,
2068                                         KM_USER1);
2069                 }
2070                 push_space -= btrfs_item_size(right, item);
2071                 btrfs_set_item_offset(right, item, push_space);
2072         }
2073
2074         if (right->map_token) {
2075                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2076                 right->map_token = NULL;
2077         }
2078         left_nritems -= push_items;
2079         btrfs_set_header_nritems(left, left_nritems);
2080
2081         if (left_nritems)
2082                 btrfs_mark_buffer_dirty(left);
2083         btrfs_mark_buffer_dirty(right);
2084
2085         ret = btrfs_update_ref(trans, root, left, right, 0, push_items);
2086         BUG_ON(ret);
2087
2088         btrfs_item_key(right, &disk_key, 0);
2089         btrfs_set_node_key(upper, &disk_key, slot + 1);
2090         btrfs_mark_buffer_dirty(upper);
2091
2092         /* then fixup the leaf pointer in the path */
2093         if (path->slots[0] >= left_nritems) {
2094                 path->slots[0] -= left_nritems;
2095                 if (btrfs_header_nritems(path->nodes[0]) == 0)
2096                         clean_tree_block(trans, root, path->nodes[0]);
2097                 btrfs_tree_unlock(path->nodes[0]);
2098                 free_extent_buffer(path->nodes[0]);
2099                 path->nodes[0] = right;
2100                 path->slots[1] += 1;
2101         } else {
2102                 btrfs_tree_unlock(right);
2103                 free_extent_buffer(right);
2104         }
2105         return 0;
2106
2107 out_unlock:
2108         btrfs_tree_unlock(right);
2109         free_extent_buffer(right);
2110         return 1;
2111 }
2112
2113 /*
2114  * push some data in the path leaf to the left, trying to free up at
2115  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
2116  */
2117 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
2118                           *root, struct btrfs_path *path, int data_size,
2119                           int empty)
2120 {
2121         struct btrfs_disk_key disk_key;
2122         struct extent_buffer *right = path->nodes[0];
2123         struct extent_buffer *left;
2124         int slot;
2125         int i;
2126         int free_space;
2127         int push_space = 0;
2128         int push_items = 0;
2129         struct btrfs_item *item;
2130         u32 old_left_nritems;
2131         u32 right_nritems;
2132         u32 nr;
2133         int ret = 0;
2134         int wret;
2135         u32 this_item_size;
2136         u32 old_left_item_size;
2137
2138         slot = path->slots[1];
2139         if (slot == 0)
2140                 return 1;
2141         if (!path->nodes[1])
2142                 return 1;
2143
2144         right_nritems = btrfs_header_nritems(right);
2145         if (right_nritems == 0) {
2146                 return 1;
2147         }
2148
2149         WARN_ON(!btrfs_tree_locked(path->nodes[1]));
2150
2151         left = read_node_slot(root, path->nodes[1], slot - 1);
2152         btrfs_tree_lock(left);
2153         free_space = btrfs_leaf_free_space(root, left);
2154         if (free_space < data_size + sizeof(struct btrfs_item)) {
2155                 ret = 1;
2156                 goto out;
2157         }
2158
2159         /* cow and double check */
2160         ret = btrfs_cow_block(trans, root, left,
2161                               path->nodes[1], slot - 1, &left, 0);
2162         if (ret) {
2163                 /* we hit -ENOSPC, but it isn't fatal here */
2164                 ret = 1;
2165                 goto out;
2166         }
2167
2168         free_space = btrfs_leaf_free_space(root, left);
2169         if (free_space < data_size + sizeof(struct btrfs_item)) {
2170                 ret = 1;
2171                 goto out;
2172         }
2173
2174         if (empty)
2175                 nr = right_nritems;
2176         else
2177                 nr = right_nritems - 1;
2178
2179         for (i = 0; i < nr; i++) {
2180                 item = btrfs_item_nr(right, i);
2181                 if (!right->map_token) {
2182                         map_extent_buffer(right, (unsigned long)item,
2183                                         sizeof(struct btrfs_item),
2184                                         &right->map_token, &right->kaddr,
2185                                         &right->map_start, &right->map_len,
2186                                         KM_USER1);
2187                 }
2188
2189                 if (!empty && push_items > 0) {
2190                         if (path->slots[0] < i)
2191                                 break;
2192                         if (path->slots[0] == i) {
2193                                 int space = btrfs_leaf_free_space(root, right);
2194                                 if (space + push_space * 2 > free_space)
2195                                         break;
2196                         }
2197                 }
2198
2199                 if (path->slots[0] == i)
2200                         push_space += data_size + sizeof(*item);
2201
2202                 this_item_size = btrfs_item_size(right, item);
2203                 if (this_item_size + sizeof(*item) + push_space > free_space)
2204                         break;
2205
2206                 push_items++;
2207                 push_space += this_item_size + sizeof(*item);
2208         }
2209
2210         if (right->map_token) {
2211                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2212                 right->map_token = NULL;
2213         }
2214
2215         if (push_items == 0) {
2216                 ret = 1;
2217                 goto out;
2218         }
2219         if (!empty && push_items == btrfs_header_nritems(right))
2220                 WARN_ON(1);
2221
2222         /* push data from right to left */
2223         copy_extent_buffer(left, right,
2224                            btrfs_item_nr_offset(btrfs_header_nritems(left)),
2225                            btrfs_item_nr_offset(0),
2226                            push_items * sizeof(struct btrfs_item));
2227
2228         push_space = BTRFS_LEAF_DATA_SIZE(root) -
2229                      btrfs_item_offset_nr(right, push_items -1);
2230
2231         copy_extent_buffer(left, right, btrfs_leaf_data(left) +
2232                      leaf_data_end(root, left) - push_space,
2233                      btrfs_leaf_data(right) +
2234                      btrfs_item_offset_nr(right, push_items - 1),
2235                      push_space);
2236         old_left_nritems = btrfs_header_nritems(left);
2237         BUG_ON(old_left_nritems < 0);
2238
2239         old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
2240         for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
2241                 u32 ioff;
2242
2243                 item = btrfs_item_nr(left, i);
2244                 if (!left->map_token) {
2245                         map_extent_buffer(left, (unsigned long)item,
2246                                         sizeof(struct btrfs_item),
2247                                         &left->map_token, &left->kaddr,
2248                                         &left->map_start, &left->map_len,
2249                                         KM_USER1);
2250                 }
2251
2252                 ioff = btrfs_item_offset(left, item);
2253                 btrfs_set_item_offset(left, item,
2254                       ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
2255         }
2256         btrfs_set_header_nritems(left, old_left_nritems + push_items);
2257         if (left->map_token) {
2258                 unmap_extent_buffer(left, left->map_token, KM_USER1);
2259                 left->map_token = NULL;
2260         }
2261
2262         /* fixup right node */
2263         if (push_items > right_nritems) {
2264                 printk("push items %d nr %u\n", push_items, right_nritems);
2265                 WARN_ON(1);
2266         }
2267
2268         if (push_items < right_nritems) {
2269                 push_space = btrfs_item_offset_nr(right, push_items - 1) -
2270                                                   leaf_data_end(root, right);
2271                 memmove_extent_buffer(right, btrfs_leaf_data(right) +
2272                                       BTRFS_LEAF_DATA_SIZE(root) - push_space,
2273                                       btrfs_leaf_data(right) +
2274                                       leaf_data_end(root, right), push_space);
2275
2276                 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
2277                               btrfs_item_nr_offset(push_items),
2278                              (btrfs_header_nritems(right) - push_items) *
2279                              sizeof(struct btrfs_item));
2280         }
2281         right_nritems -= push_items;
2282         btrfs_set_header_nritems(right, right_nritems);
2283         push_space = BTRFS_LEAF_DATA_SIZE(root);
2284         for (i = 0; i < right_nritems; i++) {
2285                 item = btrfs_item_nr(right, i);
2286
2287                 if (!right->map_token) {
2288                         map_extent_buffer(right, (unsigned long)item,
2289                                         sizeof(struct btrfs_item),
2290                                         &right->map_token, &right->kaddr,
2291                                         &right->map_start, &right->map_len,
2292                                         KM_USER1);
2293                 }
2294
2295                 push_space = push_space - btrfs_item_size(right, item);
2296                 btrfs_set_item_offset(right, item, push_space);
2297         }
2298         if (right->map_token) {
2299                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2300                 right->map_token = NULL;
2301         }
2302
2303         btrfs_mark_buffer_dirty(left);
2304         if (right_nritems)
2305                 btrfs_mark_buffer_dirty(right);
2306
2307         ret = btrfs_update_ref(trans, root, right, left,
2308                                old_left_nritems, push_items);
2309         BUG_ON(ret);
2310
2311         btrfs_item_key(right, &disk_key, 0);
2312         wret = fixup_low_keys(trans, root, path, &disk_key, 1);
2313         if (wret)
2314                 ret = wret;
2315
2316         /* then fixup the leaf pointer in the path */
2317         if (path->slots[0] < push_items) {
2318                 path->slots[0] += old_left_nritems;
2319                 if (btrfs_header_nritems(path->nodes[0]) == 0)
2320                         clean_tree_block(trans, root, path->nodes[0]);
2321                 btrfs_tree_unlock(path->nodes[0]);
2322                 free_extent_buffer(path->nodes[0]);
2323                 path->nodes[0] = left;
2324                 path->slots[1] -= 1;
2325         } else {
2326                 btrfs_tree_unlock(left);
2327                 free_extent_buffer(left);
2328                 path->slots[0] -= push_items;
2329         }
2330         BUG_ON(path->slots[0] < 0);
2331         return ret;
2332 out:
2333         btrfs_tree_unlock(left);
2334         free_extent_buffer(left);
2335         return ret;
2336 }
2337
2338 /*
2339  * split the path's leaf in two, making sure there is at least data_size
2340  * available for the resulting leaf level of the path.
2341  *
2342  * returns 0 if all went well and < 0 on failure.
2343  */
2344 static noinline int split_leaf(struct btrfs_trans_handle *trans,
2345                                struct btrfs_root *root,
2346                                struct btrfs_key *ins_key,
2347                                struct btrfs_path *path, int data_size,
2348                                int extend)
2349 {
2350         struct extent_buffer *l;
2351         u32 nritems;
2352         int mid;
2353         int slot;
2354         struct extent_buffer *right;
2355         int space_needed = data_size + sizeof(struct btrfs_item);
2356         int data_copy_size;
2357         int rt_data_off;
2358         int i;
2359         int ret = 0;
2360         int wret;
2361         int double_split;
2362         int num_doubles = 0;
2363         struct btrfs_disk_key disk_key;
2364
2365         if (extend)
2366                 space_needed = data_size;
2367
2368         /* first try to make some room by pushing left and right */
2369         if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
2370                 wret = push_leaf_right(trans, root, path, data_size, 0);
2371                 if (wret < 0) {
2372                         return wret;
2373                 }
2374                 if (wret) {
2375                         wret = push_leaf_left(trans, root, path, data_size, 0);
2376                         if (wret < 0)
2377                                 return wret;
2378                 }
2379                 l = path->nodes[0];
2380
2381                 /* did the pushes work? */
2382                 if (btrfs_leaf_free_space(root, l) >= space_needed)
2383                         return 0;
2384         }
2385
2386         if (!path->nodes[1]) {
2387                 ret = insert_new_root(trans, root, path, 1);
2388                 if (ret)
2389                         return ret;
2390         }
2391 again:
2392         double_split = 0;
2393         l = path->nodes[0];
2394         slot = path->slots[0];
2395         nritems = btrfs_header_nritems(l);
2396         mid = (nritems + 1)/ 2;
2397
2398         right = btrfs_alloc_free_block(trans, root, root->leafsize,
2399                                         path->nodes[1]->start,
2400                                         root->root_key.objectid,
2401                                         trans->transid, 0, l->start, 0);
2402         if (IS_ERR(right)) {
2403                 BUG_ON(1);
2404                 return PTR_ERR(right);
2405         }
2406
2407         memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2408         btrfs_set_header_bytenr(right, right->start);
2409         btrfs_set_header_generation(right, trans->transid);
2410         btrfs_set_header_owner(right, root->root_key.objectid);
2411         btrfs_set_header_level(right, 0);
2412         write_extent_buffer(right, root->fs_info->fsid,
2413                             (unsigned long)btrfs_header_fsid(right),
2414                             BTRFS_FSID_SIZE);
2415
2416         write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2417                             (unsigned long)btrfs_header_chunk_tree_uuid(right),
2418                             BTRFS_UUID_SIZE);
2419         if (mid <= slot) {
2420                 if (nritems == 1 ||
2421                     leaf_space_used(l, mid, nritems - mid) + space_needed >
2422                         BTRFS_LEAF_DATA_SIZE(root)) {
2423                         if (slot >= nritems) {
2424                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2425                                 btrfs_set_header_nritems(right, 0);
2426                                 wret = insert_ptr(trans, root, path,
2427                                                   &disk_key, right->start,
2428                                                   path->slots[1] + 1, 1);
2429                                 if (wret)
2430                                         ret = wret;
2431
2432                                 btrfs_tree_unlock(path->nodes[0]);
2433                                 free_extent_buffer(path->nodes[0]);
2434                                 path->nodes[0] = right;
2435                                 path->slots[0] = 0;
2436                                 path->slots[1] += 1;
2437                                 btrfs_mark_buffer_dirty(right);
2438                                 return ret;
2439                         }
2440                         mid = slot;
2441                         if (mid != nritems &&
2442                             leaf_space_used(l, mid, nritems - mid) +
2443                             space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2444                                 double_split = 1;
2445                         }
2446                 }
2447         } else {
2448                 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2449                         BTRFS_LEAF_DATA_SIZE(root)) {
2450                         if (!extend && slot == 0) {
2451                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2452                                 btrfs_set_header_nritems(right, 0);
2453                                 wret = insert_ptr(trans, root, path,
2454                                                   &disk_key,
2455                                                   right->start,
2456                                                   path->slots[1], 1);
2457                                 if (wret)
2458                                         ret = wret;
2459                                 btrfs_tree_unlock(path->nodes[0]);
2460                                 free_extent_buffer(path->nodes[0]);
2461                                 path->nodes[0] = right;
2462                                 path->slots[0] = 0;
2463                                 if (path->slots[1] == 0) {
2464                                         wret = fixup_low_keys(trans, root,
2465                                                    path, &disk_key, 1);
2466                                         if (wret)
2467                                                 ret = wret;
2468                                 }
2469                                 btrfs_mark_buffer_dirty(right);
2470                                 return ret;
2471                         } else if (extend && slot == 0) {
2472                                 mid = 1;
2473                         } else {
2474                                 mid = slot;
2475                                 if (mid != nritems &&
2476                                     leaf_space_used(l, mid, nritems - mid) +
2477                                     space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2478                                         double_split = 1;
2479                                 }
2480                         }
2481                 }
2482         }
2483         nritems = nritems - mid;
2484         btrfs_set_header_nritems(right, nritems);
2485         data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2486
2487         copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2488                            btrfs_item_nr_offset(mid),
2489                            nritems * sizeof(struct btrfs_item));
2490
2491         copy_extent_buffer(right, l,
2492                      btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2493                      data_copy_size, btrfs_leaf_data(l) +
2494                      leaf_data_end(root, l), data_copy_size);
2495
2496         rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2497                       btrfs_item_end_nr(l, mid);
2498
2499         for (i = 0; i < nritems; i++) {
2500                 struct btrfs_item *item = btrfs_item_nr(right, i);
2501                 u32 ioff;
2502
2503                 if (!right->map_token) {
2504                         map_extent_buffer(right, (unsigned long)item,
2505                                         sizeof(struct btrfs_item),
2506                                         &right->map_token, &right->kaddr,
2507                                         &right->map_start, &right->map_len,
2508                                         KM_USER1);
2509                 }
2510
2511                 ioff = btrfs_item_offset(right, item);
2512                 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2513         }
2514
2515         if (right->map_token) {
2516                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2517                 right->map_token = NULL;
2518         }
2519
2520         btrfs_set_header_nritems(l, mid);
2521         ret = 0;
2522         btrfs_item_key(right, &disk_key, 0);
2523         wret = insert_ptr(trans, root, path, &disk_key, right->start,
2524                           path->slots[1] + 1, 1);
2525         if (wret)
2526                 ret = wret;
2527
2528         btrfs_mark_buffer_dirty(right);
2529         btrfs_mark_buffer_dirty(l);
2530         BUG_ON(path->slots[0] != slot);
2531
2532         ret = btrfs_update_ref(trans, root, l, right, 0, nritems);
2533         BUG_ON(ret);
2534
2535         if (mid <= slot) {
2536                 btrfs_tree_unlock(path->nodes[0]);
2537                 free_extent_buffer(path->nodes[0]);
2538                 path->nodes[0] = right;
2539                 path->slots[0] -= mid;
2540                 path->slots[1] += 1;
2541         } else {
2542                 btrfs_tree_unlock(right);
2543                 free_extent_buffer(right);
2544         }
2545
2546         BUG_ON(path->slots[0] < 0);
2547
2548         if (double_split) {
2549                 BUG_ON(num_doubles != 0);
2550                 num_doubles++;
2551                 goto again;
2552         }
2553         return ret;
2554 }
2555
2556 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2557                         struct btrfs_root *root,
2558                         struct btrfs_path *path,
2559                         u32 new_size, int from_end)
2560 {
2561         int ret = 0;
2562         int slot;
2563         int slot_orig;
2564         struct extent_buffer *leaf;
2565         struct btrfs_item *item;
2566         u32 nritems;
2567         unsigned int data_end;
2568         unsigned int old_data_start;
2569         unsigned int old_size;
2570         unsigned int size_diff;
2571         int i;
2572
2573         slot_orig = path->slots[0];
2574         leaf = path->nodes[0];
2575         slot = path->slots[0];
2576
2577         old_size = btrfs_item_size_nr(leaf, slot);
2578         if (old_size == new_size)
2579                 return 0;
2580
2581         nritems = btrfs_header_nritems(leaf);
2582         data_end = leaf_data_end(root, leaf);
2583
2584         old_data_start = btrfs_item_offset_nr(leaf, slot);
2585
2586         size_diff = old_size - new_size;
2587
2588         BUG_ON(slot < 0);
2589         BUG_ON(slot >= nritems);
2590
2591         /*
2592          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2593          */
2594         /* first correct the data pointers */
2595         for (i = slot; i < nritems; i++) {
2596                 u32 ioff;
2597                 item = btrfs_item_nr(leaf, i);
2598
2599                 if (!leaf->map_token) {
2600                         map_extent_buffer(leaf, (unsigned long)item,
2601                                         sizeof(struct btrfs_item),
2602                                         &leaf->map_token, &leaf->kaddr,
2603                                         &leaf->map_start, &leaf->map_len,
2604                                         KM_USER1);
2605                 }
2606
2607                 ioff = btrfs_item_offset(leaf, item);
2608                 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2609         }
2610
2611         if (leaf->map_token) {
2612                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2613                 leaf->map_token = NULL;
2614         }
2615
2616         /* shift the data */
2617         if (from_end) {
2618                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2619                               data_end + size_diff, btrfs_leaf_data(leaf) +
2620                               data_end, old_data_start + new_size - data_end);
2621         } else {
2622                 struct btrfs_disk_key disk_key;
2623                 u64 offset;
2624
2625                 btrfs_item_key(leaf, &disk_key, slot);
2626
2627                 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2628                         unsigned long ptr;
2629                         struct btrfs_file_extent_item *fi;
2630
2631                         fi = btrfs_item_ptr(leaf, slot,
2632                                             struct btrfs_file_extent_item);
2633                         fi = (struct btrfs_file_extent_item *)(
2634                              (unsigned long)fi - size_diff);
2635
2636                         if (btrfs_file_extent_type(leaf, fi) ==
2637                             BTRFS_FILE_EXTENT_INLINE) {
2638                                 ptr = btrfs_item_ptr_offset(leaf, slot);
2639                                 memmove_extent_buffer(leaf, ptr,
2640                                         (unsigned long)fi,
2641                                         offsetof(struct btrfs_file_extent_item,
2642                                                  disk_bytenr));
2643                         }
2644                 }
2645
2646                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2647                               data_end + size_diff, btrfs_leaf_data(leaf) +
2648                               data_end, old_data_start - data_end);
2649
2650                 offset = btrfs_disk_key_offset(&disk_key);
2651                 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2652                 btrfs_set_item_key(leaf, &disk_key, slot);
2653                 if (slot == 0)
2654                         fixup_low_keys(trans, root, path, &disk_key, 1);
2655         }
2656
2657         item = btrfs_item_nr(leaf, slot);
2658         btrfs_set_item_size(leaf, item, new_size);
2659         btrfs_mark_buffer_dirty(leaf);
2660
2661         ret = 0;
2662         if (btrfs_leaf_free_space(root, leaf) < 0) {
2663                 btrfs_print_leaf(root, leaf);
2664                 BUG();
2665         }
2666         return ret;
2667 }
2668
2669 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2670                       struct btrfs_root *root, struct btrfs_path *path,
2671                       u32 data_size)
2672 {
2673         int ret = 0;
2674         int slot;
2675         int slot_orig;
2676         struct extent_buffer *leaf;
2677         struct btrfs_item *item;
2678         u32 nritems;
2679         unsigned int data_end;
2680         unsigned int old_data;
2681         unsigned int old_size;
2682         int i;
2683
2684         slot_orig = path->slots[0];
2685         leaf = path->nodes[0];
2686
2687         nritems = btrfs_header_nritems(leaf);
2688         data_end = leaf_data_end(root, leaf);
2689
2690         if (btrfs_leaf_free_space(root, leaf) < data_size) {
2691                 btrfs_print_leaf(root, leaf);
2692                 BUG();
2693         }
2694         slot = path->slots[0];
2695         old_data = btrfs_item_end_nr(leaf, slot);
2696
2697         BUG_ON(slot < 0);
2698         if (slot >= nritems) {
2699                 btrfs_print_leaf(root, leaf);
2700                 printk("slot %d too large, nritems %d\n", slot, nritems);
2701                 BUG_ON(1);
2702         }
2703
2704         /*
2705          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2706          */
2707         /* first correct the data pointers */
2708         for (i = slot; i < nritems; i++) {
2709                 u32 ioff;
2710                 item = btrfs_item_nr(leaf, i);
2711
2712                 if (!leaf->map_token) {
2713                         map_extent_buffer(leaf, (unsigned long)item,
2714                                         sizeof(struct btrfs_item),
2715                                         &leaf->map_token, &leaf->kaddr,
2716                                         &leaf->map_start, &leaf->map_len,
2717                                         KM_USER1);
2718                 }
2719                 ioff = btrfs_item_offset(leaf, item);
2720                 btrfs_set_item_offset(leaf, item, ioff - data_size);
2721         }
2722
2723         if (leaf->map_token) {
2724                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2725                 leaf->map_token = NULL;
2726         }
2727
2728         /* shift the data */
2729         memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2730                       data_end - data_size, btrfs_leaf_data(leaf) +
2731                       data_end, old_data - data_end);
2732
2733         data_end = old_data;
2734         old_size = btrfs_item_size_nr(leaf, slot);
2735         item = btrfs_item_nr(leaf, slot);
2736         btrfs_set_item_size(leaf, item, old_size + data_size);
2737         btrfs_mark_buffer_dirty(leaf);
2738
2739         ret = 0;
2740         if (btrfs_leaf_free_space(root, leaf) < 0) {
2741                 btrfs_print_leaf(root, leaf);
2742                 BUG();
2743         }
2744         return ret;
2745 }
2746
2747 /*
2748  * Given a key and some data, insert an item into the tree.
2749  * This does all the path init required, making room in the tree if needed.
2750  */
2751 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2752                             struct btrfs_root *root,
2753                             struct btrfs_path *path,
2754                             struct btrfs_key *cpu_key, u32 *data_size,
2755                             int nr)
2756 {
2757         struct extent_buffer *leaf;
2758         struct btrfs_item *item;
2759         int ret = 0;
2760         int slot;
2761         int slot_orig;
2762         int i;
2763         u32 nritems;
2764         u32 total_size = 0;
2765         u32 total_data = 0;
2766         unsigned int data_end;
2767         struct btrfs_disk_key disk_key;
2768
2769         for (i = 0; i < nr; i++) {
2770                 total_data += data_size[i];
2771         }
2772
2773         total_size = total_data + (nr * sizeof(struct btrfs_item));
2774         ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2775         if (ret == 0)
2776                 return -EEXIST;
2777         if (ret < 0)
2778                 goto out;
2779
2780         slot_orig = path->slots[0];
2781         leaf = path->nodes[0];
2782
2783         nritems = btrfs_header_nritems(leaf);
2784         data_end = leaf_data_end(root, leaf);
2785
2786         if (btrfs_leaf_free_space(root, leaf) < total_size) {
2787                 btrfs_print_leaf(root, leaf);
2788                 printk("not enough freespace need %u have %d\n",
2789                        total_size, btrfs_leaf_free_space(root, leaf));
2790                 BUG();
2791         }
2792
2793         slot = path->slots[0];
2794         BUG_ON(slot < 0);
2795
2796         if (slot != nritems) {
2797                 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2798
2799                 if (old_data < data_end) {
2800                         btrfs_print_leaf(root, leaf);
2801                         printk("slot %d old_data %d data_end %d\n",
2802                                slot, old_data, data_end);
2803                         BUG_ON(1);
2804                 }
2805                 /*
2806                  * item0..itemN ... dataN.offset..dataN.size .. data0.size
2807                  */
2808                 /* first correct the data pointers */
2809                 WARN_ON(leaf->map_token);
2810                 for (i = slot; i < nritems; i++) {
2811                         u32 ioff;
2812
2813                         item = btrfs_item_nr(leaf, i);
2814                         if (!leaf->map_token) {
2815                                 map_extent_buffer(leaf, (unsigned long)item,
2816                                         sizeof(struct btrfs_item),
2817                                         &leaf->map_token, &leaf->kaddr,
2818                                         &leaf->map_start, &leaf->map_len,
2819                                         KM_USER1);
2820                         }
2821
2822                         ioff = btrfs_item_offset(leaf, item);
2823                         btrfs_set_item_offset(leaf, item, ioff - total_data);
2824                 }
2825                 if (leaf->map_token) {
2826                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2827                         leaf->map_token = NULL;
2828                 }
2829
2830                 /* shift the items */
2831                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2832                               btrfs_item_nr_offset(slot),
2833                               (nritems - slot) * sizeof(struct btrfs_item));
2834
2835                 /* shift the data */
2836                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2837                               data_end - total_data, btrfs_leaf_data(leaf) +
2838                               data_end, old_data - data_end);
2839                 data_end = old_data;
2840         }
2841
2842         /* setup the item for the new data */
2843         for (i = 0; i < nr; i++) {
2844                 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2845                 btrfs_set_item_key(leaf, &disk_key, slot + i);
2846                 item = btrfs_item_nr(leaf, slot + i);
2847                 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2848                 data_end -= data_size[i];
2849                 btrfs_set_item_size(leaf, item, data_size[i]);
2850         }
2851         btrfs_set_header_nritems(leaf, nritems + nr);
2852         btrfs_mark_buffer_dirty(leaf);
2853
2854         ret = 0;
2855         if (slot == 0) {
2856                 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2857                 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2858         }
2859
2860         if (btrfs_leaf_free_space(root, leaf) < 0) {
2861                 btrfs_print_leaf(root, leaf);
2862                 BUG();
2863         }
2864 out:
2865         return ret;
2866 }
2867
2868 /*
2869  * Given a key and some data, insert an item into the tree.
2870  * This does all the path init required, making room in the tree if needed.
2871  */
2872 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2873                       *root, struct btrfs_key *cpu_key, void *data, u32
2874                       data_size)
2875 {
2876         int ret = 0;
2877         struct btrfs_path *path;
2878         struct extent_buffer *leaf;
2879         unsigned long ptr;
2880
2881         path = btrfs_alloc_path();
2882         BUG_ON(!path);
2883         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2884         if (!ret) {
2885                 leaf = path->nodes[0];
2886                 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2887                 write_extent_buffer(leaf, data, ptr, data_size);
2888                 btrfs_mark_buffer_dirty(leaf);
2889         }
2890         btrfs_free_path(path);
2891         return ret;
2892 }
2893
2894 /*
2895  * delete the pointer from a given node.
2896  *
2897  * If the delete empties a node, the node is removed from the tree,
2898  * continuing all the way the root if required.  The root is converted into
2899  * a leaf if all the nodes are emptied.
2900  */
2901 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2902                    struct btrfs_path *path, int level, int slot)
2903 {
2904         struct extent_buffer *parent = path->nodes[level];
2905         u32 nritems;
2906         int ret = 0;
2907         int wret;
2908
2909         nritems = btrfs_header_nritems(parent);
2910         if (slot != nritems -1) {
2911                 memmove_extent_buffer(parent,
2912                               btrfs_node_key_ptr_offset(slot),
2913                               btrfs_node_key_ptr_offset(slot + 1),
2914                               sizeof(struct btrfs_key_ptr) *
2915                               (nritems - slot - 1));
2916         }
2917         nritems--;
2918         btrfs_set_header_nritems(parent, nritems);
2919         if (nritems == 0 && parent == root->node) {
2920                 BUG_ON(btrfs_header_level(root->node) != 1);
2921                 /* just turn the root into a leaf and break */
2922                 btrfs_set_header_level(root->node, 0);
2923         } else if (slot == 0) {
2924                 struct btrfs_disk_key disk_key;
2925
2926                 btrfs_node_key(parent, &disk_key, 0);
2927                 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2928                 if (wret)
2929                         ret = wret;
2930         }
2931         btrfs_mark_buffer_dirty(parent);
2932         return ret;
2933 }
2934
2935 /*
2936  * delete the item at the leaf level in path.  If that empties
2937  * the leaf, remove it from the tree
2938  */
2939 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2940                     struct btrfs_path *path, int slot, int nr)
2941 {
2942         struct extent_buffer *leaf;
2943         struct btrfs_item *item;
2944         int last_off;
2945         int dsize = 0;
2946         int ret = 0;
2947         int wret;
2948         int i;
2949         u32 nritems;
2950
2951         leaf = path->nodes[0];
2952         last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2953
2954         for (i = 0; i < nr; i++)
2955                 dsize += btrfs_item_size_nr(leaf, slot + i);
2956
2957         nritems = btrfs_header_nritems(leaf);
2958
2959         if (slot + nr != nritems) {
2960                 int data_end = leaf_data_end(root, leaf);
2961
2962                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2963                               data_end + dsize,
2964                               btrfs_leaf_data(leaf) + data_end,
2965                               last_off - data_end);
2966
2967                 for (i = slot + nr; i < nritems; i++) {
2968                         u32 ioff;
2969
2970                         item = btrfs_item_nr(leaf, i);
2971                         if (!leaf->map_token) {
2972                                 map_extent_buffer(leaf, (unsigned long)item,
2973                                         sizeof(struct btrfs_item),
2974                                         &leaf->map_token, &leaf->kaddr,
2975                                         &leaf->map_start, &leaf->map_len,
2976                                         KM_USER1);
2977                         }
2978                         ioff = btrfs_item_offset(leaf, item);
2979                         btrfs_set_item_offset(leaf, item, ioff + dsize);
2980                 }
2981
2982                 if (leaf->map_token) {
2983                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2984                         leaf->map_token = NULL;
2985                 }
2986
2987                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2988                               btrfs_item_nr_offset(slot + nr),
2989                               sizeof(struct btrfs_item) *
2990                               (nritems - slot - nr));
2991         }
2992         btrfs_set_header_nritems(leaf, nritems - nr);
2993         nritems -= nr;
2994
2995         /* delete the leaf if we've emptied it */
2996         if (nritems == 0) {
2997                 if (leaf == root->node) {
2998                         btrfs_set_header_level(leaf, 0);
2999                 } else {
3000                         u64 root_gen = btrfs_header_generation(path->nodes[1]);
3001                         wret = del_ptr(trans, root, path, 1, path->slots[1]);
3002                         if (wret)
3003                                 ret = wret;
3004                         wret = btrfs_free_extent(trans, root,
3005                                          leaf->start, leaf->len,
3006                                          path->nodes[1]->start,
3007                                          btrfs_header_owner(path->nodes[1]),
3008                                          root_gen, 0, 0, 1);
3009                         if (wret)
3010                                 ret = wret;
3011                 }
3012         } else {
3013                 int used = leaf_space_used(leaf, 0, nritems);
3014                 if (slot == 0) {
3015                         struct btrfs_disk_key disk_key;
3016
3017                         btrfs_item_key(leaf, &disk_key, 0);
3018                         wret = fixup_low_keys(trans, root, path,
3019                                               &disk_key, 1);
3020                         if (wret)
3021                                 ret = wret;
3022                 }
3023
3024                 /* delete the leaf if it is mostly empty */
3025                 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
3026                         /* push_leaf_left fixes the path.
3027                          * make sure the path still points to our leaf
3028                          * for possible call to del_ptr below
3029                          */
3030                         slot = path->slots[1];
3031                         extent_buffer_get(leaf);
3032
3033                         wret = push_leaf_left(trans, root, path, 1, 1);
3034                         if (wret < 0 && wret != -ENOSPC)
3035                                 ret = wret;
3036
3037                         if (path->nodes[0] == leaf &&
3038                             btrfs_header_nritems(leaf)) {
3039                                 wret = push_leaf_right(trans, root, path, 1, 1);
3040                                 if (wret < 0 && wret != -ENOSPC)
3041                                         ret = wret;
3042                         }
3043
3044                         if (btrfs_header_nritems(leaf) == 0) {
3045                                 u64 root_gen;
3046                                 u64 bytenr = leaf->start;
3047                                 u32 blocksize = leaf->len;
3048
3049                                 root_gen = btrfs_header_generation(
3050                                                            path->nodes[1]);
3051
3052                                 wret = del_ptr(trans, root, path, 1, slot);
3053                                 if (wret)
3054                                         ret = wret;
3055
3056                                 free_extent_buffer(leaf);
3057                                 wret = btrfs_free_extent(trans, root, bytenr,
3058                                              blocksize, path->nodes[1]->start,
3059                                              btrfs_header_owner(path->nodes[1]),
3060                                              root_gen, 0, 0, 1);
3061                                 if (wret)
3062                                         ret = wret;
3063                         } else {
3064                                 /* if we're still in the path, make sure
3065                                  * we're dirty.  Otherwise, one of the
3066                                  * push_leaf functions must have already
3067                                  * dirtied this buffer
3068                                  */
3069                                 if (path->nodes[0] == leaf)
3070                                         btrfs_mark_buffer_dirty(leaf);
3071                                 free_extent_buffer(leaf);
3072                         }
3073                 } else {
3074                         btrfs_mark_buffer_dirty(leaf);
3075                 }
3076         }
3077         return ret;
3078 }
3079
3080 /*
3081  * search the tree again to find a leaf with lesser keys
3082  * returns 0 if it found something or 1 if there are no lesser leaves.
3083  * returns < 0 on io errors.
3084  */
3085 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
3086 {
3087         struct btrfs_key key;
3088         struct btrfs_disk_key found_key;
3089         int ret;
3090
3091         btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
3092
3093         if (key.offset > 0)
3094                 key.offset--;
3095         else if (key.type > 0)
3096                 key.type--;
3097         else if (key.objectid > 0)
3098                 key.objectid--;
3099         else
3100                 return 1;
3101
3102         btrfs_release_path(root, path);
3103         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3104         if (ret < 0)
3105                 return ret;
3106         btrfs_item_key(path->nodes[0], &found_key, 0);
3107         ret = comp_keys(&found_key, &key);
3108         if (ret < 0)
3109                 return 0;
3110         return 1;
3111 }
3112
3113 /*
3114  * A helper function to walk down the tree starting at min_key, and looking
3115  * for nodes or leaves that are either in cache or have a minimum
3116  * transaction id.  This is used by the btree defrag code, but could
3117  * also be used to search for blocks that have changed since a given
3118  * transaction id.
3119  *
3120  * This does not cow, but it does stuff the starting key it finds back
3121  * into min_key, so you can call btrfs_search_slot with cow=1 on the
3122  * key and get a writable path.
3123  *
3124  * This does lock as it descends, and path->keep_locks should be set
3125  * to 1 by the caller.
3126  *
3127  * This honors path->lowest_level to prevent descent past a given level
3128  * of the tree.
3129  *
3130  * returns zero if something useful was found, < 0 on error and 1 if there
3131  * was nothing in the tree that matched the search criteria.
3132  */
3133 int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
3134                          struct btrfs_key *max_key,
3135                          struct btrfs_path *path, int cache_only,
3136                          u64 min_trans)
3137 {
3138         struct extent_buffer *cur;
3139         struct btrfs_key found_key;
3140         int slot;
3141         int sret;
3142         u32 nritems;
3143         int level;
3144         int ret = 1;
3145
3146 again:
3147         cur = btrfs_lock_root_node(root);
3148         level = btrfs_header_level(cur);
3149         WARN_ON(path->nodes[level]);
3150         path->nodes[level] = cur;
3151         path->locks[level] = 1;
3152
3153         if (btrfs_header_generation(cur) < min_trans) {
3154                 ret = 1;
3155                 goto out;
3156         }
3157         while(1) {
3158                 nritems = btrfs_header_nritems(cur);
3159                 level = btrfs_header_level(cur);
3160                 sret = bin_search(cur, min_key, level, &slot);
3161
3162                 /* at level = 0, we're done, setup the path and exit */
3163                 if (level == 0) {
3164                         if (slot >= nritems)
3165                                 goto find_next_key;
3166                         ret = 0;
3167                         path->slots[level] = slot;
3168                         btrfs_item_key_to_cpu(cur, &found_key, slot);
3169                         goto out;
3170                 }
3171                 if (sret && slot > 0)
3172                         slot--;
3173                 /*
3174                  * check this node pointer against the cache_only and
3175                  * min_trans parameters.  If it isn't in cache or is too
3176                  * old, skip to the next one.
3177                  */
3178                 while(slot < nritems) {
3179                         u64 blockptr;
3180                         u64 gen;
3181                         struct extent_buffer *tmp;
3182                         struct btrfs_disk_key disk_key;
3183
3184                         blockptr = btrfs_node_blockptr(cur, slot);
3185                         gen = btrfs_node_ptr_generation(cur, slot);
3186                         if (gen < min_trans) {
3187                                 slot++;
3188                                 continue;
3189                         }
3190                         if (!cache_only)
3191                                 break;
3192
3193                         if (max_key) {
3194                                 btrfs_node_key(cur, &disk_key, slot);
3195                                 if (comp_keys(&disk_key, max_key) >= 0) {
3196                                         ret = 1;
3197                                         goto out;
3198                                 }
3199                         }
3200
3201                         tmp = btrfs_find_tree_block(root, blockptr,
3202                                             btrfs_level_size(root, level - 1));
3203
3204                         if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
3205                                 free_extent_buffer(tmp);
3206                                 break;
3207                         }
3208                         if (tmp)
3209                                 free_extent_buffer(tmp);
3210                         slot++;
3211                 }
3212 find_next_key:
3213                 /*
3214                  * we didn't find a candidate key in this node, walk forward
3215                  * and find another one
3216                  */
3217                 if (slot >= nritems) {
3218                         path->slots[level] = slot;
3219                         sret = btrfs_find_next_key(root, path, min_key, level,
3220                                                   cache_only, min_trans);
3221                         if (sret == 0) {
3222                                 btrfs_release_path(root, path);
3223                                 goto again;
3224                         } else {
3225                                 goto out;
3226                         }
3227                 }
3228                 /* save our key for returning back */
3229                 btrfs_node_key_to_cpu(cur, &found_key, slot);
3230                 path->slots[level] = slot;
3231                 if (level == path->lowest_level) {
3232                         ret = 0;
3233                         unlock_up(path, level, 1);
3234                         goto out;
3235                 }
3236                 cur = read_node_slot(root, cur, slot);
3237
3238                 btrfs_tree_lock(cur);
3239                 path->locks[level - 1] = 1;
3240                 path->nodes[level - 1] = cur;
3241                 unlock_up(path, level, 1);
3242         }
3243 out:
3244         if (ret == 0)
3245                 memcpy(min_key, &found_key, sizeof(found_key));
3246         return ret;
3247 }
3248
3249 /*
3250  * this is similar to btrfs_next_leaf, but does not try to preserve
3251  * and fixup the path.  It looks for and returns the next key in the
3252  * tree based on the current path and the cache_only and min_trans
3253  * parameters.
3254  *
3255  * 0 is returned if another key is found, < 0 if there are any errors
3256  * and 1 is returned if there are no higher keys in the tree
3257  *
3258  * path->keep_locks should be set to 1 on the search made before
3259  * calling this function.
3260  */
3261 int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
3262                         struct btrfs_key *key, int lowest_level,
3263                         int cache_only, u64 min_trans)
3264 {
3265         int level = lowest_level;
3266         int slot;
3267         struct extent_buffer *c;
3268
3269         while(level < BTRFS_MAX_LEVEL) {
3270                 if (!path->nodes[level])
3271                         return 1;
3272
3273                 slot = path->slots[level] + 1;
3274                 c = path->nodes[level];
3275 next:
3276                 if (slot >= btrfs_header_nritems(c)) {
3277                         level++;
3278                         if (level == BTRFS_MAX_LEVEL) {
3279                                 return 1;
3280                         }
3281                         continue;
3282                 }
3283                 if (level == 0)
3284                         btrfs_item_key_to_cpu(c, key, slot);
3285                 else {
3286                         u64 blockptr = btrfs_node_blockptr(c, slot);
3287                         u64 gen = btrfs_node_ptr_generation(c, slot);
3288
3289                         if (cache_only) {
3290                                 struct extent_buffer *cur;
3291                                 cur = btrfs_find_tree_block(root, blockptr,
3292                                             btrfs_level_size(root, level - 1));
3293                                 if (!cur || !btrfs_buffer_uptodate(cur, gen)) {
3294                                         slot++;
3295                                         if (cur)
3296                                                 free_extent_buffer(cur);
3297                                         goto next;
3298                                 }
3299                                 free_extent_buffer(cur);
3300                         }
3301                         if (gen < min_trans) {
3302                                 slot++;
3303                                 goto next;
3304                         }
3305                         btrfs_node_key_to_cpu(c, key, slot);
3306                 }
3307                 return 0;
3308         }
3309         return 1;
3310 }
3311
3312 /*
3313  * search the tree again to find a leaf with greater keys
3314  * returns 0 if it found something or 1 if there are no greater leaves.
3315  * returns < 0 on io errors.
3316  */
3317 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
3318 {
3319         int slot;
3320         int level = 1;
3321         struct extent_buffer *c;
3322         struct extent_buffer *next = NULL;
3323         struct btrfs_key key;
3324         u32 nritems;
3325         int ret;
3326
3327         nritems = btrfs_header_nritems(path->nodes[0]);
3328         if (nritems == 0) {
3329                 return 1;
3330         }
3331
3332         btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
3333
3334         btrfs_release_path(root, path);
3335         path->keep_locks = 1;
3336         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3337         path->keep_locks = 0;
3338
3339         if (ret < 0)
3340                 return ret;
3341
3342         nritems = btrfs_header_nritems(path->nodes[0]);
3343         /*
3344          * by releasing the path above we dropped all our locks.  A balance
3345          * could have added more items next to the key that used to be
3346          * at the very end of the block.  So, check again here and
3347          * advance the path if there are now more items available.
3348          */
3349         if (nritems > 0 && path->slots[0] < nritems - 1) {
3350                 path->slots[0]++;
3351                 goto done;
3352         }
3353
3354         while(level < BTRFS_MAX_LEVEL) {
3355                 if (!path->nodes[level])
3356                         return 1;
3357
3358                 slot = path->slots[level] + 1;
3359                 c = path->nodes[level];
3360                 if (slot >= btrfs_header_nritems(c)) {
3361                         level++;
3362                         if (level == BTRFS_MAX_LEVEL) {
3363                                 return 1;
3364                         }
3365                         continue;
3366                 }
3367
3368                 if (next) {
3369                         btrfs_tree_unlock(next);
3370                         free_extent_buffer(next);
3371                 }
3372
3373                 if (level == 1 && (path->locks[1] || path->skip_locking) &&
3374                     path->reada)
3375                         reada_for_search(root, path, level, slot, 0);
3376
3377                 next = read_node_slot(root, c, slot);
3378                 if (!path->skip_locking) {
3379                         WARN_ON(!btrfs_tree_locked(c));
3380                         btrfs_tree_lock(next);
3381                 }
3382                 break;
3383         }
3384         path->slots[level] = slot;
3385         while(1) {
3386                 level--;
3387                 c = path->nodes[level];
3388                 if (path->locks[level])
3389                         btrfs_tree_unlock(c);
3390                 free_extent_buffer(c);
3391                 path->nodes[level] = next;
3392                 path->slots[level] = 0;
3393                 if (!path->skip_locking)
3394                         path->locks[level] = 1;
3395                 if (!level)
3396                         break;
3397                 if (level == 1 && path->locks[1] && path->reada)
3398                         reada_for_search(root, path, level, slot, 0);
3399                 next = read_node_slot(root, next, 0);
3400                 if (!path->skip_locking) {
3401                         WARN_ON(!btrfs_tree_locked(path->nodes[level]));
3402                         btrfs_tree_lock(next);
3403                 }
3404         }
3405 done:
3406         unlock_up(path, 0, 1);
3407         return 0;
3408 }
3409
3410 /*
3411  * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
3412  * searching until it gets past min_objectid or finds an item of 'type'
3413  *
3414  * returns 0 if something is found, 1 if nothing was found and < 0 on error
3415  */
3416 int btrfs_previous_item(struct btrfs_root *root,
3417                         struct btrfs_path *path, u64 min_objectid,
3418                         int type)
3419 {
3420         struct btrfs_key found_key;
3421         struct extent_buffer *leaf;
3422         u32 nritems;
3423         int ret;
3424
3425         while(1) {
3426                 if (path->slots[0] == 0) {
3427                         ret = btrfs_prev_leaf(root, path);
3428                         if (ret != 0)
3429                                 return ret;
3430                 } else {
3431                         path->slots[0]--;
3432                 }
3433                 leaf = path->nodes[0];
3434                 nritems = btrfs_header_nritems(leaf);
3435                 if (nritems == 0)
3436                         return 1;
3437                 if (path->slots[0] == nritems)
3438                         path->slots[0]--;
3439
3440                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3441                 if (found_key.type == type)
3442                         return 0;
3443                 if (found_key.objectid < min_objectid)
3444                         break;
3445                 if (found_key.objectid == min_objectid &&
3446                     found_key.type < type)
3447                         break;
3448         }
3449         return 1;
3450 }