fs/btrfs/ctree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/sched.h>
  20 #include "ctree.h"
  21 #include "disk-io.h"
  22 #include "transaction.h"
  23 #include "print-tree.h"
  24 #include "locking.h"
  25
  26 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
  27                       *root, struct btrfs_path *path, int level);
  28 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
  29                       *root, struct btrfs_key *ins_key,
  30                       struct btrfs_path *path, int data_size, int extend);
  31 static int push_node_left(struct btrfs_trans_handle *trans,
  32                           struct btrfs_root *root, struct extent_buffer *dst,
  33                           struct extent_buffer *src, int empty);
  34 static int balance_node_right(struct btrfs_trans_handle *trans,
  35                               struct btrfs_root *root,
  36                               struct extent_buffer *dst_buf,
  37                               struct extent_buffer *src_buf);
  38 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  39                    struct btrfs_path *path, int level, int slot);
  40
  41 inline void btrfs_init_path(struct btrfs_path *p)
  42 {
  43         memset(p, 0, sizeof(*p));
  44 }
  45
  46 struct btrfs_path *btrfs_alloc_path(void)
  47 {
  48         struct btrfs_path *path;
  49         path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
  50         if (path) {
  51                 btrfs_init_path(path);
  52                 path->reada = 1;
  53         }
  54         return path;
  55 }
  56
  57 void btrfs_free_path(struct btrfs_path *p)
  58 {
  59         btrfs_release_path(NULL, p);
  60         kmem_cache_free(btrfs_path_cachep, p);
  61 }
  62
  63 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
  64 {
  65         int i;
  66         int keep = p->keep_locks;
  67         int skip = p->skip_locking;
  68
  69         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
  70                 if (!p->nodes[i])
  71                         continue;
  72                 if (p->locks[i]) {
  73                         btrfs_tree_unlock(p->nodes[i]);
  74                         p->locks[i] = 0;
  75                 }
  76                 free_extent_buffer(p->nodes[i]);
  77         }
  78         memset(p, 0, sizeof(*p));
  79         p->keep_locks = keep;
  80         p->skip_locking = skip;
  81 }
  82
  83 struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
  84 {
  85         struct extent_buffer *eb;
  86         spin_lock(&root->node_lock);
  87         eb = root->node;
  88         extent_buffer_get(eb);
  89         spin_unlock(&root->node_lock);
  90         return eb;
  91 }
  92
  93 struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
  94 {
  95         struct extent_buffer *eb;
  96
  97         while(1) {
  98                 eb = btrfs_root_node(root);
  99                 btrfs_tree_lock(eb);
 100
 101                 spin_lock(&root->node_lock);
 102                 if (eb == root->node) {
 103                         spin_unlock(&root->node_lock);
 104                         break;
 105                 }
 106                 spin_unlock(&root->node_lock);
 107
 108                 btrfs_tree_unlock(eb);
 109                 free_extent_buffer(eb);
 110         }
 111         return eb;
 112 }
 113
 114 static void add_root_to_dirty_list(struct btrfs_root *root)
 115 {
 116         if (root->track_dirty && list_empty(&root->dirty_list)) {
 117                 list_add(&root->dirty_list,
 118                          &root->fs_info->dirty_cowonly_roots);
 119         }
 120 }
 121
 122 int btrfs_copy_root(struct btrfs_trans_handle *trans,
 123                       struct btrfs_root *root,
 124                       struct extent_buffer *buf,
 125                       struct extent_buffer **cow_ret, u64 new_root_objectid)
 126 {
 127         struct extent_buffer *cow;
 128         u32 nritems;
 129         int ret = 0;
 130         int level;
 131         struct btrfs_key first_key;
 132         struct btrfs_root *new_root;
 133
 134         new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
 135         if (!new_root)
 136                 return -ENOMEM;
 137
 138         memcpy(new_root, root, sizeof(*new_root));
 139         new_root->root_key.objectid = new_root_objectid;
 140
 141         WARN_ON(root->ref_cows && trans->transid !=
 142                 root->fs_info->running_transaction->transid);
 143         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 144
 145         level = btrfs_header_level(buf);
 146         nritems = btrfs_header_nritems(buf);
 147         if (nritems) {
 148                 if (level == 0)
 149                         btrfs_item_key_to_cpu(buf, &first_key, 0);
 150                 else
 151                         btrfs_node_key_to_cpu(buf, &first_key, 0);
 152         } else {
 153                 first_key.objectid = 0;
 154         }
 155         cow = btrfs_alloc_free_block(trans, new_root, buf->len,
 156                                        new_root_objectid,
 157                                        trans->transid, first_key.objectid,
 158                                        level, buf->start, 0);
 159         if (IS_ERR(cow)) {
 160                 kfree(new_root);
 161                 return PTR_ERR(cow);
 162         }
 163
 164         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 165         btrfs_set_header_bytenr(cow, cow->start);
 166         btrfs_set_header_generation(cow, trans->transid);
 167         btrfs_set_header_owner(cow, new_root_objectid);
 168         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 169
 170         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 171         ret = btrfs_inc_ref(trans, new_root, buf);
 172         kfree(new_root);
 173
 174         if (ret)
 175                 return ret;
 176
 177         btrfs_mark_buffer_dirty(cow);
 178         *cow_ret = cow;
 179         return 0;
 180 }
 181
 182 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 183                              struct btrfs_root *root,
 184                              struct extent_buffer *buf,
 185                              struct extent_buffer *parent, int parent_slot,
 186                              struct extent_buffer **cow_ret,
 187                              u64 search_start, u64 empty_size)
 188 {
 189         u64 root_gen;
 190         struct extent_buffer *cow;
 191         u32 nritems;
 192         int ret = 0;
 193         int different_trans = 0;
 194         int level;
 195         int unlock_orig = 0;
 196         struct btrfs_key first_key;
 197
 198         if (*cow_ret == buf)
 199                 unlock_orig = 1;
 200
 201         WARN_ON(!btrfs_tree_locked(buf));
 202
 203         if (root->ref_cows) {
 204                 root_gen = trans->transid;
 205         } else {
 206                 root_gen = 0;
 207         }
 208         WARN_ON(root->ref_cows && trans->transid !=
 209                 root->fs_info->running_transaction->transid);
 210         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 211
 212         level = btrfs_header_level(buf);
 213         nritems = btrfs_header_nritems(buf);
 214         if (nritems) {
 215                 if (level == 0)
 216                         btrfs_item_key_to_cpu(buf, &first_key, 0);
 217                 else
 218                         btrfs_node_key_to_cpu(buf, &first_key, 0);
 219         } else {
 220                 first_key.objectid = 0;
 221         }
 222         cow = btrfs_alloc_free_block(trans, root, buf->len,
 223                                      root->root_key.objectid,
 224                                      root_gen, first_key.objectid, level,
 225                                      search_start, empty_size);
 226         if (IS_ERR(cow))
 227                 return PTR_ERR(cow);
 228
 229         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 230         btrfs_set_header_bytenr(cow, cow->start);
 231         btrfs_set_header_generation(cow, trans->transid);
 232         btrfs_set_header_owner(cow, root->root_key.objectid);
 233         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 234
 235         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 236         if (btrfs_header_generation(buf) != trans->transid) {
 237                 different_trans = 1;
 238                 ret = btrfs_inc_ref(trans, root, buf);
 239                 if (ret)
 240                         return ret;
 241         } else {
 242                 clean_tree_block(trans, root, buf);
 243         }
 244
 245         if (buf == root->node) {
 246                 WARN_ON(parent && parent != buf);
 247                 root_gen = btrfs_header_generation(buf);
 248
 249                 spin_lock(&root->node_lock);
 250                 root->node = cow;
 251                 extent_buffer_get(cow);
 252                 spin_unlock(&root->node_lock);
 253
 254                 if (buf != root->commit_root) {
 255                         btrfs_free_extent(trans, root, buf->start,
 256                                           buf->len, root->root_key.objectid,
 257                                           root_gen, 0, 0, 1);
 258                 }
 259                 free_extent_buffer(buf);
 260                 add_root_to_dirty_list(root);
 261         } else {
 262                 root_gen = btrfs_header_generation(parent);
 263                 btrfs_set_node_blockptr(parent, parent_slot,
 264                                         cow->start);
 265                 WARN_ON(trans->transid == 0);
 266                 btrfs_set_node_ptr_generation(parent, parent_slot,
 267                                               trans->transid);
 268                 btrfs_mark_buffer_dirty(parent);
 269                 WARN_ON(btrfs_header_generation(parent) != trans->transid);
 270                 btrfs_free_extent(trans, root, buf->start, buf->len,
 271                                   btrfs_header_owner(parent), root_gen,
 272                                   0, 0, 1);
 273         }
 274         if (unlock_orig)
 275                 btrfs_tree_unlock(buf);
 276         free_extent_buffer(buf);
 277         btrfs_mark_buffer_dirty(cow);
 278         *cow_ret = cow;
 279         return 0;
 280 }
 281
 282 int btrfs_cow_block(struct btrfs_trans_handle *trans,
 283                     struct btrfs_root *root, struct extent_buffer *buf,
 284                     struct extent_buffer *parent, int parent_slot,
 285                     struct extent_buffer **cow_ret)
 286 {
 287         u64 search_start;
 288         u64 header_trans;
 289         int ret;
 290
 291         if (trans->transaction != root->fs_info->running_transaction) {
 292                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 293                        root->fs_info->running_transaction->transid);
 294                 WARN_ON(1);
 295         }
 296         if (trans->transid != root->fs_info->generation) {
 297                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 298                        root->fs_info->generation);
 299                 WARN_ON(1);
 300         }
 301
 302         header_trans = btrfs_header_generation(buf);
 303         spin_lock(&root->fs_info->hash_lock);
 304         if (header_trans == trans->transid &&
 305             !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
 306                 *cow_ret = buf;
 307                 spin_unlock(&root->fs_info->hash_lock);
 308                 return 0;
 309         }
 310         spin_unlock(&root->fs_info->hash_lock);
 311         search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
 312         ret = __btrfs_cow_block(trans, root, buf, parent,
 313                                  parent_slot, cow_ret, search_start, 0);
 314         return ret;
 315 }
 316
 317 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
 318 {
 319         if (blocknr < other && other - (blocknr + blocksize) < 32768)
 320                 return 1;
 321         if (blocknr > other && blocknr - (other + blocksize) < 32768)
 322                 return 1;
 323         return 0;
 324 }
 325
 326 /*
 327  * compare two keys in a memcmp fashion
 328  */
 329 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
 330 {
 331         struct btrfs_key k1;
 332
 333         btrfs_disk_key_to_cpu(&k1, disk);
 334
 335         if (k1.objectid > k2->objectid)
 336                 return 1;
 337         if (k1.objectid < k2->objectid)
 338                 return -1;
 339         if (k1.type > k2->type)
 340                 return 1;
 341         if (k1.type < k2->type)
 342                 return -1;
 343         if (k1.offset > k2->offset)
 344                 return 1;
 345         if (k1.offset < k2->offset)
 346                 return -1;
 347         return 0;
 348 }
 349
 350
 351 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 352                        struct btrfs_root *root, struct extent_buffer *parent,
 353                        int start_slot, int cache_only, u64 *last_ret,
 354                        struct btrfs_key *progress)
 355 {
 356         struct extent_buffer *cur;
 357         struct extent_buffer *tmp;
 358         u64 blocknr;
 359         u64 gen;
 360         u64 search_start = *last_ret;
 361         u64 last_block = 0;
 362         u64 other;
 363         u32 parent_nritems;
 364         int end_slot;
 365         int i;
 366         int err = 0;
 367         int parent_level;
 368         int uptodate;
 369         u32 blocksize;
 370         int progress_passed = 0;
 371         struct btrfs_disk_key disk_key;
 372
 373         /* FIXME this code needs locking */
 374         return 0;
 375
 376         parent_level = btrfs_header_level(parent);
 377         if (cache_only && parent_level != 1)
 378                 return 0;
 379
 380         if (trans->transaction != root->fs_info->running_transaction) {
 381                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 382                        root->fs_info->running_transaction->transid);
 383                 WARN_ON(1);
 384         }
 385         if (trans->transid != root->fs_info->generation) {
 386                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 387                        root->fs_info->generation);
 388                 WARN_ON(1);
 389         }
 390
 391         parent_nritems = btrfs_header_nritems(parent);
 392         blocksize = btrfs_level_size(root, parent_level - 1);
 393         end_slot = parent_nritems;
 394
 395         if (parent_nritems == 1)
 396                 return 0;
 397
 398         for (i = start_slot; i < end_slot; i++) {
 399                 int close = 1;
 400
 401                 if (!parent->map_token) {
 402                         map_extent_buffer(parent,
 403                                         btrfs_node_key_ptr_offset(i),
 404                                         sizeof(struct btrfs_key_ptr),
 405                                         &parent->map_token, &parent->kaddr,
 406                                         &parent->map_start, &parent->map_len,
 407                                         KM_USER1);
 408                 }
 409                 btrfs_node_key(parent, &disk_key, i);
 410                 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
 411                         continue;
 412
 413                 progress_passed = 1;
 414                 blocknr = btrfs_node_blockptr(parent, i);
 415                 gen = btrfs_node_ptr_generation(parent, i);
 416                 if (last_block == 0)
 417                         last_block = blocknr;
 418
 419                 if (i > 0) {
 420                         other = btrfs_node_blockptr(parent, i - 1);
 421                         close = close_blocks(blocknr, other, blocksize);
 422                 }
 423                 if (!close && i < end_slot - 2) {
 424                         other = btrfs_node_blockptr(parent, i + 1);
 425                         close = close_blocks(blocknr, other, blocksize);
 426                 }
 427                 if (close) {
 428                         last_block = blocknr;
 429                         continue;
 430                 }
 431                 if (parent->map_token) {
 432                         unmap_extent_buffer(parent, parent->map_token,
 433                                             KM_USER1);
 434                         parent->map_token = NULL;
 435                 }
 436
 437                 cur = btrfs_find_tree_block(root, blocknr, blocksize);
 438                 if (cur)
 439                         uptodate = btrfs_buffer_uptodate(cur, gen);
 440                 else
 441                         uptodate = 0;
 442                 if (!cur || !uptodate) {
 443                         if (cache_only) {
 444                                 free_extent_buffer(cur);
 445                                 continue;
 446                         }
 447                         if (!cur) {
 448                                 cur = read_tree_block(root, blocknr,
 449                                                          blocksize, gen);
 450                         } else if (!uptodate) {
 451                                 btrfs_read_buffer(cur, gen);
 452                         }
 453                 }
 454                 if (search_start == 0)
 455                         search_start = last_block;
 456
 457                 err = __btrfs_cow_block(trans, root, cur, parent, i,
 458                                         &tmp, search_start,
 459                                         min(16 * blocksize,
 460                                             (end_slot - i) * blocksize));
 461                 if (err) {
 462                         free_extent_buffer(cur);
 463                         break;
 464                 }
 465                 search_start = tmp->start;
 466                 last_block = tmp->start;
 467                 *last_ret = search_start;
 468                 if (parent_level == 1)
 469                         btrfs_clear_buffer_defrag(tmp);
 470                 free_extent_buffer(tmp);
 471         }
 472         if (parent->map_token) {
 473                 unmap_extent_buffer(parent, parent->map_token,
 474                                     KM_USER1);
 475                 parent->map_token = NULL;
 476         }
 477         return err;
 478 }
 479
 480 /*
 481  * The leaf data grows from end-to-front in the node.
 482  * this returns the address of the start of the last item,
 483  * which is the stop of the leaf data stack
 484  */
 485 static inline unsigned int leaf_data_end(struct btrfs_root *root,
 486                                          struct extent_buffer *leaf)
 487 {
 488         u32 nr = btrfs_header_nritems(leaf);
 489         if (nr == 0)
 490                 return BTRFS_LEAF_DATA_SIZE(root);
 491         return btrfs_item_offset_nr(leaf, nr - 1);
 492 }
 493
 494 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
 495                       int level)
 496 {
 497         struct extent_buffer *parent = NULL;
 498         struct extent_buffer *node = path->nodes[level];
 499         struct btrfs_disk_key parent_key;
 500         struct btrfs_disk_key node_key;
 501         int parent_slot;
 502         int slot;
 503         struct btrfs_key cpukey;
 504         u32 nritems = btrfs_header_nritems(node);
 505
 506         if (path->nodes[level + 1])
 507                 parent = path->nodes[level + 1];
 508
 509         slot = path->slots[level];
 510         BUG_ON(nritems == 0);
 511         if (parent) {
 512                 parent_slot = path->slots[level + 1];
 513                 btrfs_node_key(parent, &parent_key, parent_slot);
 514                 btrfs_node_key(node, &node_key, 0);
 515                 BUG_ON(memcmp(&parent_key, &node_key,
 516                               sizeof(struct btrfs_disk_key)));
 517                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 518                        btrfs_header_bytenr(node));
 519         }
 520         BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
 521         if (slot != 0) {
 522                 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
 523                 btrfs_node_key(node, &node_key, slot);
 524                 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
 525         }
 526         if (slot < nritems - 1) {
 527                 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
 528                 btrfs_node_key(node, &node_key, slot);
 529                 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
 530         }
 531         return 0;
 532 }
 533
 534 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
 535                       int level)
 536 {
 537         struct extent_buffer *leaf = path->nodes[level];
 538         struct extent_buffer *parent = NULL;
 539         int parent_slot;
 540         struct btrfs_key cpukey;
 541         struct btrfs_disk_key parent_key;
 542         struct btrfs_disk_key leaf_key;
 543         int slot = path->slots[0];
 544
 545         u32 nritems = btrfs_header_nritems(leaf);
 546
 547         if (path->nodes[level + 1])
 548                 parent = path->nodes[level + 1];
 549
 550         if (nritems == 0)
 551                 return 0;
 552
 553         if (parent) {
 554                 parent_slot = path->slots[level + 1];
 555                 btrfs_node_key(parent, &parent_key, parent_slot);
 556                 btrfs_item_key(leaf, &leaf_key, 0);
 557
 558                 BUG_ON(memcmp(&parent_key, &leaf_key,
 559                        sizeof(struct btrfs_disk_key)));
 560                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 561                        btrfs_header_bytenr(leaf));
 562         }
 563 #if 0
 564         for (i = 0; nritems > 1 && i < nritems - 2; i++) {
 565                 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
 566                 btrfs_item_key(leaf, &leaf_key, i);
 567                 if (comp_keys(&leaf_key, &cpukey) >= 0) {
 568                         btrfs_print_leaf(root, leaf);
 569                         printk("slot %d offset bad key\n", i);
 570                         BUG_ON(1);
 571                 }
 572                 if (btrfs_item_offset_nr(leaf, i) !=
 573                         btrfs_item_end_nr(leaf, i + 1)) {
 574                         btrfs_print_leaf(root, leaf);
 575                         printk("slot %d offset bad\n", i);
 576                         BUG_ON(1);
 577                 }
 578                 if (i == 0) {
 579                         if (btrfs_item_offset_nr(leaf, i) +
 580                                btrfs_item_size_nr(leaf, i) !=
 581                                BTRFS_LEAF_DATA_SIZE(root)) {
 582                                 btrfs_print_leaf(root, leaf);
 583                                 printk("slot %d first offset bad\n", i);
 584                                 BUG_ON(1);
 585                         }
 586                 }
 587         }
 588         if (nritems > 0) {
 589                 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
 590                                 btrfs_print_leaf(root, leaf);
 591                                 printk("slot %d bad size \n", nritems - 1);
 592                                 BUG_ON(1);
 593                 }
 594         }
 595 #endif
 596         if (slot != 0 && slot < nritems - 1) {
 597                 btrfs_item_key(leaf, &leaf_key, slot);
 598                 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
 599                 if (comp_keys(&leaf_key, &cpukey) <= 0) {
 600                         btrfs_print_leaf(root, leaf);
 601                         printk("slot %d offset bad key\n", slot);
 602                         BUG_ON(1);
 603                 }
 604                 if (btrfs_item_offset_nr(leaf, slot - 1) !=
 605                        btrfs_item_end_nr(leaf, slot)) {
 606                         btrfs_print_leaf(root, leaf);
 607                         printk("slot %d offset bad\n", slot);
 608                         BUG_ON(1);
 609                 }
 610         }
 611         if (slot < nritems - 1) {
 612                 btrfs_item_key(leaf, &leaf_key, slot);
 613                 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
 614                 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
 615                 if (btrfs_item_offset_nr(leaf, slot) !=
 616                         btrfs_item_end_nr(leaf, slot + 1)) {
 617                         btrfs_print_leaf(root, leaf);
 618                         printk("slot %d offset bad\n", slot);
 619                         BUG_ON(1);
 620                 }
 621         }
 622         BUG_ON(btrfs_item_offset_nr(leaf, 0) +
 623                btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
 624         return 0;
 625 }
 626
 627 static int noinline check_block(struct btrfs_root *root,
 628                                 struct btrfs_path *path, int level)
 629 {
 630         u64 found_start;
 631         return 0;
 632         if (btrfs_header_level(path->nodes[level]) != level)
 633             printk("warning: bad level %Lu wanted %d found %d\n",
 634                    path->nodes[level]->start, level,
 635                    btrfs_header_level(path->nodes[level]));
 636         found_start = btrfs_header_bytenr(path->nodes[level]);
 637         if (found_start != path->nodes[level]->start) {
 638             printk("warning: bad bytentr %Lu found %Lu\n",
 639                    path->nodes[level]->start, found_start);
 640         }
 641 #if 0
 642         struct extent_buffer *buf = path->nodes[level];
 643
 644         if (memcmp_extent_buffer(buf, root->fs_info->fsid,
 645                                  (unsigned long)btrfs_header_fsid(buf),
 646                                  BTRFS_FSID_SIZE)) {
 647                 printk("warning bad block %Lu\n", buf->start);
 648                 return 1;
 649         }
 650 #endif
 651         if (level == 0)
 652                 return check_leaf(root, path, level);
 653         return check_node(root, path, level);
 654 }
 655
 656 /*
 657  * search for key in the extent_buffer.  The items start at offset p,
 658  * and they are item_size apart.  There are 'max' items in p.
 659  *
 660  * the slot in the array is returned via slot, and it points to
 661  * the place where you would insert key if it is not found in
 662  * the array.
 663  *
 664  * slot may point to max if the key is bigger than all of the keys
 665  */
 666 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
 667                               int item_size, struct btrfs_key *key,
 668                               int max, int *slot)
 669 {
 670         int low = 0;
 671         int high = max;
 672         int mid;
 673         int ret;
 674         struct btrfs_disk_key *tmp = NULL;
 675         struct btrfs_disk_key unaligned;
 676         unsigned long offset;
 677         char *map_token = NULL;
 678         char *kaddr = NULL;
 679         unsigned long map_start = 0;
 680         unsigned long map_len = 0;
 681         int err;
 682
 683         while(low < high) {
 684                 mid = (low + high) / 2;
 685                 offset = p + mid * item_size;
 686
 687                 if (!map_token || offset < map_start ||
 688                     (offset + sizeof(struct btrfs_disk_key)) >
 689                     map_start + map_len) {
 690                         if (map_token) {
 691                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 692                                 map_token = NULL;
 693                         }
 694                         err = map_extent_buffer(eb, offset,
 695                                                 sizeof(struct btrfs_disk_key),
 696                                                 &map_token, &kaddr,
 697                                                 &map_start, &map_len, KM_USER0);
 698
 699                         if (!err) {
 700                                 tmp = (struct btrfs_disk_key *)(kaddr + offset -
 701                                                         map_start);
 702                         } else {
 703                                 read_extent_buffer(eb, &unaligned,
 704                                                    offset, sizeof(unaligned));
 705                                 tmp = &unaligned;
 706                         }
 707
 708                 } else {
 709                         tmp = (struct btrfs_disk_key *)(kaddr + offset -
 710                                                         map_start);
 711                 }
 712                 ret = comp_keys(tmp, key);
 713
 714                 if (ret < 0)
 715                         low = mid + 1;
 716                 else if (ret > 0)
 717                         high = mid;
 718                 else {
 719                         *slot = mid;
 720                         if (map_token)
 721                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 722                         return 0;
 723                 }
 724         }
 725         *slot = low;
 726         if (map_token)
 727                 unmap_extent_buffer(eb, map_token, KM_USER0);
 728         return 1;
 729 }
 730
 731 /*
 732  * simple bin_search frontend that does the right thing for
 733  * leaves vs nodes
 734  */
 735 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
 736                       int level, int *slot)
 737 {
 738         if (level == 0) {
 739                 return generic_bin_search(eb,
 740                                           offsetof(struct btrfs_leaf, items),
 741                                           sizeof(struct btrfs_item),
 742                                           key, btrfs_header_nritems(eb),
 743                                           slot);
 744         } else {
 745                 return generic_bin_search(eb,
 746                                           offsetof(struct btrfs_node, ptrs),
 747                                           sizeof(struct btrfs_key_ptr),
 748                                           key, btrfs_header_nritems(eb),
 749                                           slot);
 750         }
 751         return -1;
 752 }
 753
 754 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
 755                                    struct extent_buffer *parent, int slot)
 756 {
 757         int level = btrfs_header_level(parent);
 758         if (slot < 0)
 759                 return NULL;
 760         if (slot >= btrfs_header_nritems(parent))
 761                 return NULL;
 762
 763         BUG_ON(level == 0);
 764
 765         return read_tree_block(root, btrfs_node_blockptr(parent, slot),
 766                        btrfs_level_size(root, level - 1),
 767                        btrfs_node_ptr_generation(parent, slot));
 768 }
 769
 770 static int balance_level(struct btrfs_trans_handle *trans,
 771                          struct btrfs_root *root,
 772                          struct btrfs_path *path, int level)
 773 {
 774         struct extent_buffer *right = NULL;
 775         struct extent_buffer *mid;
 776         struct extent_buffer *left = NULL;
 777         struct extent_buffer *parent = NULL;
 778         int ret = 0;
 779         int wret;
 780         int pslot;
 781         int orig_slot = path->slots[level];
 782         int err_on_enospc = 0;
 783         u64 orig_ptr;
 784
 785         if (level == 0)
 786                 return 0;
 787
 788         mid = path->nodes[level];
 789         WARN_ON(!path->locks[level]);
 790         WARN_ON(btrfs_header_generation(mid) != trans->transid);
 791
 792         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 793
 794         if (level < BTRFS_MAX_LEVEL - 1)
 795                 parent = path->nodes[level + 1];
 796         pslot = path->slots[level + 1];
 797
 798         /*
 799          * deal with the case where there is only one pointer in the root
 800          * by promoting the node below to a root
 801          */
 802         if (!parent) {
 803                 struct extent_buffer *child;
 804
 805                 if (btrfs_header_nritems(mid) != 1)
 806                         return 0;
 807
 808                 /* promote the child to a root */
 809                 child = read_node_slot(root, mid, 0);
 810                 btrfs_tree_lock(child);
 811                 BUG_ON(!child);
 812                 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
 813                 BUG_ON(ret);
 814
 815                 spin_lock(&root->node_lock);
 816                 root->node = child;
 817                 spin_unlock(&root->node_lock);
 818
 819                 add_root_to_dirty_list(root);
 820                 btrfs_tree_unlock(child);
 821                 path->locks[level] = 0;
 822                 path->nodes[level] = NULL;
 823                 clean_tree_block(trans, root, mid);
 824                 btrfs_tree_unlock(mid);
 825                 /* once for the path */
 826                 free_extent_buffer(mid);
 827                 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
 828                                         root->root_key.objectid,
 829                                         btrfs_header_generation(mid), 0, 0, 1);
 830                 /* once for the root ptr */
 831                 free_extent_buffer(mid);
 832                 return ret;
 833         }
 834         if (btrfs_header_nritems(mid) >
 835             BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
 836                 return 0;
 837
 838         if (btrfs_header_nritems(mid) < 2)
 839                 err_on_enospc = 1;
 840
 841         left = read_node_slot(root, parent, pslot - 1);
 842         if (left) {
 843                 btrfs_tree_lock(left);
 844                 wret = btrfs_cow_block(trans, root, left,
 845                                        parent, pslot - 1, &left);
 846                 if (wret) {
 847                         ret = wret;
 848                         goto enospc;
 849                 }
 850         }
 851         right = read_node_slot(root, parent, pslot + 1);
 852         if (right) {
 853                 btrfs_tree_lock(right);
 854                 wret = btrfs_cow_block(trans, root, right,
 855                                        parent, pslot + 1, &right);
 856                 if (wret) {
 857                         ret = wret;
 858                         goto enospc;
 859                 }
 860         }
 861
 862         /* first, try to make some room in the middle buffer */
 863         if (left) {
 864                 orig_slot += btrfs_header_nritems(left);
 865                 wret = push_node_left(trans, root, left, mid, 1);
 866                 if (wret < 0)
 867                         ret = wret;
 868                 if (btrfs_header_nritems(mid) < 2)
 869                         err_on_enospc = 1;
 870         }
 871
 872         /*
 873          * then try to empty the right most buffer into the middle
 874          */
 875         if (right) {
 876                 wret = push_node_left(trans, root, mid, right, 1);
 877                 if (wret < 0 && wret != -ENOSPC)
 878                         ret = wret;
 879                 if (btrfs_header_nritems(right) == 0) {
 880                         u64 bytenr = right->start;
 881                         u64 generation = btrfs_header_generation(parent);
 882                         u32 blocksize = right->len;
 883
 884                         clean_tree_block(trans, root, right);
 885                         btrfs_tree_unlock(right);
 886                         free_extent_buffer(right);
 887                         right = NULL;
 888                         wret = del_ptr(trans, root, path, level + 1, pslot +
 889                                        1);
 890                         if (wret)
 891                                 ret = wret;
 892                         wret = btrfs_free_extent(trans, root, bytenr,
 893                                                  blocksize,
 894                                                  btrfs_header_owner(parent),
 895                                                  generation, 0, 0, 1);
 896                         if (wret)
 897                                 ret = wret;
 898                 } else {
 899                         struct btrfs_disk_key right_key;
 900                         btrfs_node_key(right, &right_key, 0);
 901                         btrfs_set_node_key(parent, &right_key, pslot + 1);
 902                         btrfs_mark_buffer_dirty(parent);
 903                 }
 904         }
 905         if (btrfs_header_nritems(mid) == 1) {
 906                 /*
 907                  * we're not allowed to leave a node with one item in the
 908                  * tree during a delete.  A deletion from lower in the tree
 909                  * could try to delete the only pointer in this node.
 910                  * So, pull some keys from the left.
 911                  * There has to be a left pointer at this point because
 912                  * otherwise we would have pulled some pointers from the
 913                  * right
 914                  */
 915                 BUG_ON(!left);
 916                 wret = balance_node_right(trans, root, mid, left);
 917                 if (wret < 0) {
 918                         ret = wret;
 919                         goto enospc;
 920                 }
 921                 if (wret == 1) {
 922                         wret = push_node_left(trans, root, left, mid, 1);
 923                         if (wret < 0)
 924                                 ret = wret;
 925                 }
 926                 BUG_ON(wret == 1);
 927         }
 928         if (btrfs_header_nritems(mid) == 0) {
 929                 /* we've managed to empty the middle node, drop it */
 930                 u64 root_gen = btrfs_header_generation(parent);
 931                 u64 bytenr = mid->start;
 932                 u32 blocksize = mid->len;
 933
 934                 clean_tree_block(trans, root, mid);
 935                 btrfs_tree_unlock(mid);
 936                 free_extent_buffer(mid);
 937                 mid = NULL;
 938                 wret = del_ptr(trans, root, path, level + 1, pslot);
 939                 if (wret)
 940                         ret = wret;
 941                 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
 942                                          btrfs_header_owner(parent),
 943                                          root_gen, 0, 0, 1);
 944                 if (wret)
 945                         ret = wret;
 946         } else {
 947                 /* update the parent key to reflect our changes */
 948                 struct btrfs_disk_key mid_key;
 949                 btrfs_node_key(mid, &mid_key, 0);
 950                 btrfs_set_node_key(parent, &mid_key, pslot);
 951                 btrfs_mark_buffer_dirty(parent);
 952         }
 953
 954         /* update the path */
 955         if (left) {
 956                 if (btrfs_header_nritems(left) > orig_slot) {
 957                         extent_buffer_get(left);
 958                         /* left was locked after cow */
 959                         path->nodes[level] = left;
 960                         path->slots[level + 1] -= 1;
 961                         path->slots[level] = orig_slot;
 962                         if (mid) {
 963                                 btrfs_tree_unlock(mid);
 964                                 free_extent_buffer(mid);
 965                         }
 966                 } else {
 967                         orig_slot -= btrfs_header_nritems(left);
 968                         path->slots[level] = orig_slot;
 969                 }
 970         }
 971         /* double check we haven't messed things up */
 972         check_block(root, path, level);
 973         if (orig_ptr !=
 974             btrfs_node_blockptr(path->nodes[level], path->slots[level]))
 975                 BUG();
 976 enospc:
 977         if (right) {
 978                 btrfs_tree_unlock(right);
 979                 free_extent_buffer(right);
 980         }
 981         if (left) {
 982                 if (path->nodes[level] != left)
 983                         btrfs_tree_unlock(left);
 984                 free_extent_buffer(left);
 985         }
 986         return ret;
 987 }
 988
 989 /* returns zero if the push worked, non-zero otherwise */
 990 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
 991                                           struct btrfs_root *root,
 992                                           struct btrfs_path *path, int level)
 993 {
 994         struct extent_buffer *right = NULL;
 995         struct extent_buffer *mid;
 996         struct extent_buffer *left = NULL;
 997         struct extent_buffer *parent = NULL;
 998         int ret = 0;
 999         int wret;
1000         int pslot;
1001         int orig_slot = path->slots[level];
1002         u64 orig_ptr;
1003
1004         if (level == 0)
1005                 return 1;
1006
1007         mid = path->nodes[level];
1008         WARN_ON(btrfs_header_generation(mid) != trans->transid);
1009         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
1010
1011         if (level < BTRFS_MAX_LEVEL - 1)
1012                 parent = path->nodes[level + 1];
1013         pslot = path->slots[level + 1];
1014
1015         if (!parent)
1016                 return 1;
1017
1018         left = read_node_slot(root, parent, pslot - 1);
1019
1020         /* first, try to make some room in the middle buffer */
1021         if (left) {
1022                 u32 left_nr;
1023
1024                 btrfs_tree_lock(left);
1025                 left_nr = btrfs_header_nritems(left);
1026                 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1027                         wret = 1;
1028                 } else {
1029                         ret = btrfs_cow_block(trans, root, left, parent,
1030                                               pslot - 1, &left);
1031                         if (ret)
1032                                 wret = 1;
1033                         else {
1034                                 wret = push_node_left(trans, root,
1035                                                       left, mid, 0);
1036                         }
1037                 }
1038                 if (wret < 0)
1039                         ret = wret;
1040                 if (wret == 0) {
1041                         struct btrfs_disk_key disk_key;
1042                         orig_slot += left_nr;
1043                         btrfs_node_key(mid, &disk_key, 0);
1044                         btrfs_set_node_key(parent, &disk_key, pslot);
1045                         btrfs_mark_buffer_dirty(parent);
1046                         if (btrfs_header_nritems(left) > orig_slot) {
1047                                 path->nodes[level] = left;
1048                                 path->slots[level + 1] -= 1;
1049                                 path->slots[level] = orig_slot;
1050                                 btrfs_tree_unlock(mid);
1051                                 free_extent_buffer(mid);
1052                         } else {
1053                                 orig_slot -=
1054                                         btrfs_header_nritems(left);
1055                                 path->slots[level] = orig_slot;
1056                                 btrfs_tree_unlock(left);
1057                                 free_extent_buffer(left);
1058                         }
1059                         return 0;
1060                 }
1061                 btrfs_tree_unlock(left);
1062                 free_extent_buffer(left);
1063         }
1064         right = read_node_slot(root, parent, pslot + 1);
1065
1066         /*
1067          * then try to empty the right most buffer into the middle
1068          */
1069         if (right) {
1070                 u32 right_nr;
1071                 btrfs_tree_lock(right);
1072                 right_nr = btrfs_header_nritems(right);
1073                 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1074                         wret = 1;
1075                 } else {
1076                         ret = btrfs_cow_block(trans, root, right,
1077                                               parent, pslot + 1,
1078                                               &right);
1079                         if (ret)
1080                                 wret = 1;
1081                         else {
1082                                 wret = balance_node_right(trans, root,
1083                                                           right, mid);
1084                         }
1085                 }
1086                 if (wret < 0)
1087                         ret = wret;
1088                 if (wret == 0) {
1089                         struct btrfs_disk_key disk_key;
1090
1091                         btrfs_node_key(right, &disk_key, 0);
1092                         btrfs_set_node_key(parent, &disk_key, pslot + 1);
1093                         btrfs_mark_buffer_dirty(parent);
1094
1095                         if (btrfs_header_nritems(mid) <= orig_slot) {
1096                                 path->nodes[level] = right;
1097                                 path->slots[level + 1] += 1;
1098                                 path->slots[level] = orig_slot -
1099                                         btrfs_header_nritems(mid);
1100                                 btrfs_tree_unlock(mid);
1101                                 free_extent_buffer(mid);
1102                         } else {
1103                                 btrfs_tree_unlock(right);
1104                                 free_extent_buffer(right);
1105                         }
1106                         return 0;
1107                 }
1108                 btrfs_tree_unlock(right);
1109                 free_extent_buffer(right);
1110         }
1111         return 1;
1112 }
1113
1114 /*
1115  * readahead one full node of leaves
1116  */
1117 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
1118                              int level, int slot, u64 objectid)
1119 {
1120         struct extent_buffer *node;
1121         struct btrfs_disk_key disk_key;
1122         u32 nritems;
1123         u64 search;
1124         u64 lowest_read;
1125         u64 highest_read;
1126         u64 nread = 0;
1127         int direction = path->reada;
1128         struct extent_buffer *eb;
1129         u32 nr;
1130         u32 blocksize;
1131         u32 nscan = 0;
1132
1133         if (level != 1)
1134                 return;
1135
1136         if (!path->nodes[level])
1137                 return;
1138
1139         node = path->nodes[level];
1140
1141         search = btrfs_node_blockptr(node, slot);
1142         blocksize = btrfs_level_size(root, level - 1);
1143         eb = btrfs_find_tree_block(root, search, blocksize);
1144         if (eb) {
1145                 free_extent_buffer(eb);
1146                 return;
1147         }
1148
1149         highest_read = search;
1150         lowest_read = search;
1151
1152         nritems = btrfs_header_nritems(node);
1153         nr = slot;
1154         while(1) {
1155                 if (direction < 0) {
1156                         if (nr == 0)
1157                                 break;
1158                         nr--;
1159                 } else if (direction > 0) {
1160                         nr++;
1161                         if (nr >= nritems)
1162                                 break;
1163                 }
1164                 if (path->reada < 0 && objectid) {
1165                         btrfs_node_key(node, &disk_key, nr);
1166                         if (btrfs_disk_key_objectid(&disk_key) != objectid)
1167                                 break;
1168                 }
1169                 search = btrfs_node_blockptr(node, nr);
1170                 if ((search >= lowest_read && search <= highest_read) ||
1171                     (search < lowest_read && lowest_read - search <= 32768) ||
1172                     (search > highest_read && search - highest_read <= 32768)) {
1173                         readahead_tree_block(root, search, blocksize,
1174                                      btrfs_node_ptr_generation(node, nr));
1175                         nread += blocksize;
1176                 }
1177                 nscan++;
1178                 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1179                         break;
1180                 if(nread > (1024 * 1024) || nscan > 128)
1181                         break;
1182
1183                 if (search < lowest_read)
1184                         lowest_read = search;
1185                 if (search > highest_read)
1186                         highest_read = search;
1187         }
1188 }
1189
1190 static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
1191 {
1192         int i;
1193         int skip_level = level;
1194         int no_skips = 0;
1195         struct extent_buffer *t;
1196
1197         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1198                 if (!path->nodes[i])
1199                         break;
1200                 if (!path->locks[i])
1201                         break;
1202                 if (!no_skips && path->slots[i] == 0) {
1203                         skip_level = i + 1;
1204                         continue;
1205                 }
1206                 if (!no_skips && path->keep_locks) {
1207                         u32 nritems;
1208                         t = path->nodes[i];
1209                         nritems = btrfs_header_nritems(t);
1210                         if (nritems < 1 || path->slots[i] >= nritems - 1) {
1211                                 skip_level = i + 1;
1212                                 continue;
1213                         }
1214                 }
1215                 if (skip_level < i && i >= lowest_unlock)
1216                         no_skips = 1;
1217
1218                 t = path->nodes[i];
1219                 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
1220                         btrfs_tree_unlock(t);
1221                         path->locks[i] = 0;
1222                 }
1223         }
1224 }
1225
1226 /*
1227  * look for key in the tree.  path is filled in with nodes along the way
1228  * if key is found, we return zero and you can find the item in the leaf
1229  * level of the path (level 0)
1230  *
1231  * If the key isn't found, the path points to the slot where it should
1232  * be inserted, and 1 is returned.  If there are other errors during the
1233  * search a negative error number is returned.
1234  *
1235  * if ins_len > 0, nodes and leaves will be split as we walk down the
1236  * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
1237  * possible)
1238  */
1239 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1240                       *root, struct btrfs_key *key, struct btrfs_path *p, int
1241                       ins_len, int cow)
1242 {
1243         struct extent_buffer *b;
1244         struct extent_buffer *tmp;
1245         int slot;
1246         int ret;
1247         int level;
1248         int should_reada = p->reada;
1249         int lowest_unlock = 1;
1250         int blocksize;
1251         u8 lowest_level = 0;
1252         u64 blocknr;
1253         u64 gen;
1254
1255         lowest_level = p->lowest_level;
1256         WARN_ON(lowest_level && ins_len);
1257         WARN_ON(p->nodes[0] != NULL);
1258         WARN_ON(cow && root == root->fs_info->extent_root &&
1259                 !mutex_is_locked(&root->fs_info->alloc_mutex));
1260         WARN_ON(root == root->fs_info->chunk_root &&
1261                 !mutex_is_locked(&root->fs_info->chunk_mutex));
1262         WARN_ON(root == root->fs_info->dev_root &&
1263                 !mutex_is_locked(&root->fs_info->chunk_mutex));
1264         if (ins_len < 0)
1265                 lowest_unlock = 2;
1266 again:
1267         if (p->skip_locking)
1268                 b = btrfs_root_node(root);
1269         else
1270                 b = btrfs_lock_root_node(root);
1271
1272         while (b) {
1273                 level = btrfs_header_level(b);
1274                 if (cow) {
1275                         int wret;
1276                         wret = btrfs_cow_block(trans, root, b,
1277                                                p->nodes[level + 1],
1278                                                p->slots[level + 1],
1279                                                &b);
1280                         if (wret) {
1281                                 free_extent_buffer(b);
1282                                 return wret;
1283                         }
1284                 }
1285                 BUG_ON(!cow && ins_len);
1286                 if (level != btrfs_header_level(b))
1287                         WARN_ON(1);
1288                 level = btrfs_header_level(b);
1289                 p->nodes[level] = b;
1290                 if (!p->skip_locking)
1291                         p->locks[level] = 1;
1292                 ret = check_block(root, p, level);
1293                 if (ret)
1294                         return -1;
1295
1296                 ret = bin_search(b, key, level, &slot);
1297                 if (level != 0) {
1298                         if (ret && slot > 0)
1299                                 slot -= 1;
1300                         p->slots[level] = slot;
1301                         if (ins_len > 0 && btrfs_header_nritems(b) >=
1302                             BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1303                                 int sret = split_node(trans, root, p, level);
1304                                 BUG_ON(sret > 0);
1305                                 if (sret)
1306                                         return sret;
1307                                 b = p->nodes[level];
1308                                 slot = p->slots[level];
1309                         } else if (ins_len < 0) {
1310                                 int sret = balance_level(trans, root, p,
1311                                                          level);
1312                                 if (sret)
1313                                         return sret;
1314                                 b = p->nodes[level];
1315                                 if (!b) {
1316                                         btrfs_release_path(NULL, p);
1317                                         goto again;
1318                                 }
1319                                 slot = p->slots[level];
1320                                 BUG_ON(btrfs_header_nritems(b) == 1);
1321                         }
1322                         /* this is only true while dropping a snapshot */
1323                         if (level == lowest_level) {
1324                                 unlock_up(p, level, lowest_unlock);
1325                                 break;
1326                         }
1327
1328                         if (should_reada)
1329                                 reada_for_search(root, p, level, slot,
1330                                                  key->objectid);
1331
1332                         blocknr = btrfs_node_blockptr(b, slot);
1333                         gen = btrfs_node_ptr_generation(b, slot);
1334                         blocksize = btrfs_level_size(root, level - 1);
1335
1336                         tmp = btrfs_find_tree_block(root, blocknr, blocksize);
1337                         if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
1338                                 b = tmp;
1339                         } else {
1340                                 /*
1341                                  * reduce lock contention at high levels
1342                                  * of the btree by dropping locks before
1343                                  * we read.
1344                                  */
1345                                 if (level > 1) {
1346                                         btrfs_release_path(NULL, p);
1347                                         if (tmp)
1348                                                 free_extent_buffer(tmp);
1349                                         tmp = read_tree_block(root, blocknr,
1350                                                          blocksize, gen);
1351                                         if (tmp)
1352                                                 free_extent_buffer(tmp);
1353                                         goto again;
1354                                 } else {
1355                                         if (tmp)
1356                                                 free_extent_buffer(tmp);
1357                                         b = read_node_slot(root, b, slot);
1358                                 }
1359                         }
1360                         if (!p->skip_locking)
1361                                 btrfs_tree_lock(b);
1362                         unlock_up(p, level, lowest_unlock);
1363                 } else {
1364                         p->slots[level] = slot;
1365                         if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1366                             sizeof(struct btrfs_item) + ins_len) {
1367                                 int sret = split_leaf(trans, root, key,
1368                                                       p, ins_len, ret == 0);
1369                                 BUG_ON(sret > 0);
1370                                 if (sret)
1371                                         return sret;
1372                         }
1373                         unlock_up(p, level, lowest_unlock);
1374                         return ret;
1375                 }
1376         }
1377         return 1;
1378 }
1379
1380 /*
1381  * adjust the pointers going up the tree, starting at level
1382  * making sure the right key of each node is points to 'key'.
1383  * This is used after shifting pointers to the left, so it stops
1384  * fixing up pointers when a given leaf/node is not in slot 0 of the
1385  * higher levels
1386  *
1387  * If this fails to write a tree block, it returns -1, but continues
1388  * fixing up the blocks in ram so the tree is consistent.
1389  */
1390 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1391                           struct btrfs_root *root, struct btrfs_path *path,
1392                           struct btrfs_disk_key *key, int level)
1393 {
1394         int i;
1395         int ret = 0;
1396         struct extent_buffer *t;
1397
1398         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1399                 int tslot = path->slots[i];
1400                 if (!path->nodes[i])
1401                         break;
1402                 t = path->nodes[i];
1403                 btrfs_set_node_key(t, key, tslot);
1404                 btrfs_mark_buffer_dirty(path->nodes[i]);
1405                 if (tslot != 0)
1406                         break;
1407         }
1408         return ret;
1409 }
1410
1411 /*
1412  * try to push data from one node into the next node left in the
1413  * tree.
1414  *
1415  * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1416  * error, and > 0 if there was no room in the left hand block.
1417  */
1418 static int push_node_left(struct btrfs_trans_handle *trans,
1419                           struct btrfs_root *root, struct extent_buffer *dst,
1420                           struct extent_buffer *src, int empty)
1421 {
1422         int push_items = 0;
1423         int src_nritems;
1424         int dst_nritems;
1425         int ret = 0;
1426
1427         src_nritems = btrfs_header_nritems(src);
1428         dst_nritems = btrfs_header_nritems(dst);
1429         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1430         WARN_ON(btrfs_header_generation(src) != trans->transid);
1431         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1432
1433         if (!empty && src_nritems <= 8)
1434                 return 1;
1435
1436         if (push_items <= 0) {
1437                 return 1;
1438         }
1439
1440         if (empty) {
1441                 push_items = min(src_nritems, push_items);
1442                 if (push_items < src_nritems) {
1443                         /* leave at least 8 pointers in the node if
1444                          * we aren't going to empty it
1445                          */
1446                         if (src_nritems - push_items < 8) {
1447                                 if (push_items <= 8)
1448                                         return 1;
1449                                 push_items -= 8;
1450                         }
1451                 }
1452         } else
1453                 push_items = min(src_nritems - 8, push_items);
1454
1455         copy_extent_buffer(dst, src,
1456                            btrfs_node_key_ptr_offset(dst_nritems),
1457                            btrfs_node_key_ptr_offset(0),
1458                            push_items * sizeof(struct btrfs_key_ptr));
1459
1460         if (push_items < src_nritems) {
1461                 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1462                                       btrfs_node_key_ptr_offset(push_items),
1463                                       (src_nritems - push_items) *
1464                                       sizeof(struct btrfs_key_ptr));
1465         }
1466         btrfs_set_header_nritems(src, src_nritems - push_items);
1467         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1468         btrfs_mark_buffer_dirty(src);
1469         btrfs_mark_buffer_dirty(dst);
1470         return ret;
1471 }
1472
1473 /*
1474  * try to push data from one node into the next node right in the
1475  * tree.
1476  *
1477  * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1478  * error, and > 0 if there was no room in the right hand block.
1479  *
1480  * this will  only push up to 1/2 the contents of the left node over
1481  */
1482 static int balance_node_right(struct btrfs_trans_handle *trans,
1483                               struct btrfs_root *root,
1484                               struct extent_buffer *dst,
1485                               struct extent_buffer *src)
1486 {
1487         int push_items = 0;
1488         int max_push;
1489         int src_nritems;
1490         int dst_nritems;
1491         int ret = 0;
1492
1493         WARN_ON(btrfs_header_generation(src) != trans->transid);
1494         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1495
1496         src_nritems = btrfs_header_nritems(src);
1497         dst_nritems = btrfs_header_nritems(dst);
1498         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1499         if (push_items <= 0) {
1500                 return 1;
1501         }
1502
1503         if (src_nritems < 4) {
1504                 return 1;
1505         }
1506
1507         max_push = src_nritems / 2 + 1;
1508         /* don't try to empty the node */
1509         if (max_push >= src_nritems) {
1510                 return 1;
1511         }
1512
1513         if (max_push < push_items)
1514                 push_items = max_push;
1515
1516         memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1517                                       btrfs_node_key_ptr_offset(0),
1518                                       (dst_nritems) *
1519                                       sizeof(struct btrfs_key_ptr));
1520
1521         copy_extent_buffer(dst, src,
1522                            btrfs_node_key_ptr_offset(0),
1523                            btrfs_node_key_ptr_offset(src_nritems - push_items),
1524                            push_items * sizeof(struct btrfs_key_ptr));
1525
1526         btrfs_set_header_nritems(src, src_nritems - push_items);
1527         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1528
1529         btrfs_mark_buffer_dirty(src);
1530         btrfs_mark_buffer_dirty(dst);
1531         return ret;
1532 }
1533
1534 /*
1535  * helper function to insert a new root level in the tree.
1536  * A new node is allocated, and a single item is inserted to
1537  * point to the existing root
1538  *
1539  * returns zero on success or < 0 on failure.
1540  */
1541 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1542                            struct btrfs_root *root,
1543                            struct btrfs_path *path, int level)
1544 {
1545         u64 root_gen;
1546         u64 lower_gen;
1547         struct extent_buffer *lower;
1548         struct extent_buffer *c;
1549         struct extent_buffer *old;
1550         struct btrfs_disk_key lower_key;
1551
1552         BUG_ON(path->nodes[level]);
1553         BUG_ON(path->nodes[level-1] != root->node);
1554
1555         if (root->ref_cows)
1556                 root_gen = trans->transid;
1557         else
1558                 root_gen = 0;
1559
1560         lower = path->nodes[level-1];
1561         if (level == 1)
1562                 btrfs_item_key(lower, &lower_key, 0);
1563         else
1564                 btrfs_node_key(lower, &lower_key, 0);
1565
1566         c = btrfs_alloc_free_block(trans, root, root->nodesize,
1567                                    root->root_key.objectid,
1568                                    root_gen, lower_key.objectid, level,
1569                                    root->node->start, 0);
1570         if (IS_ERR(c))
1571                 return PTR_ERR(c);
1572
1573         memset_extent_buffer(c, 0, 0, root->nodesize);
1574         btrfs_set_header_nritems(c, 1);
1575         btrfs_set_header_level(c, level);
1576         btrfs_set_header_bytenr(c, c->start);
1577         btrfs_set_header_generation(c, trans->transid);
1578         btrfs_set_header_owner(c, root->root_key.objectid);
1579
1580         write_extent_buffer(c, root->fs_info->fsid,
1581                             (unsigned long)btrfs_header_fsid(c),
1582                             BTRFS_FSID_SIZE);
1583
1584         write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1585                             (unsigned long)btrfs_header_chunk_tree_uuid(c),
1586                             BTRFS_UUID_SIZE);
1587
1588         btrfs_set_node_key(c, &lower_key, 0);
1589         btrfs_set_node_blockptr(c, 0, lower->start);
1590         lower_gen = btrfs_header_generation(lower);
1591         WARN_ON(lower_gen == 0);
1592
1593         btrfs_set_node_ptr_generation(c, 0, lower_gen);
1594
1595         btrfs_mark_buffer_dirty(c);
1596
1597         spin_lock(&root->node_lock);
1598         old = root->node;
1599         root->node = c;
1600         spin_unlock(&root->node_lock);
1601
1602         /* the super has an extra ref to root->node */
1603         free_extent_buffer(old);
1604
1605         add_root_to_dirty_list(root);
1606         extent_buffer_get(c);
1607         path->nodes[level] = c;
1608         path->locks[level] = 1;
1609         path->slots[level] = 0;
1610
1611         if (root->ref_cows && lower_gen != trans->transid) {
1612                 struct btrfs_path *back_path = btrfs_alloc_path();
1613                 int ret;
1614                 mutex_lock(&root->fs_info->alloc_mutex);
1615                 ret = btrfs_insert_extent_backref(trans,
1616                                                   root->fs_info->extent_root,
1617                                                   path, lower->start,
1618                                                   root->root_key.objectid,
1619                                                   trans->transid, 0, 0);
1620                 BUG_ON(ret);
1621                 mutex_unlock(&root->fs_info->alloc_mutex);
1622                 btrfs_free_path(back_path);
1623         }
1624         return 0;
1625 }
1626
1627 /*
1628  * worker function to insert a single pointer in a node.
1629  * the node should have enough room for the pointer already
1630  *
1631  * slot and level indicate where you want the key to go, and
1632  * blocknr is the block the key points to.
1633  *
1634  * returns zero on success and < 0 on any error
1635  */
1636 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1637                       *root, struct btrfs_path *path, struct btrfs_disk_key
1638                       *key, u64 bytenr, int slot, int level)
1639 {
1640         struct extent_buffer *lower;
1641         int nritems;
1642
1643         BUG_ON(!path->nodes[level]);
1644         lower = path->nodes[level];
1645         nritems = btrfs_header_nritems(lower);
1646         if (slot > nritems)
1647                 BUG();
1648         if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1649                 BUG();
1650         if (slot != nritems) {
1651                 memmove_extent_buffer(lower,
1652                               btrfs_node_key_ptr_offset(slot + 1),
1653                               btrfs_node_key_ptr_offset(slot),
1654                               (nritems - slot) * sizeof(struct btrfs_key_ptr));
1655         }
1656         btrfs_set_node_key(lower, key, slot);
1657         btrfs_set_node_blockptr(lower, slot, bytenr);
1658         WARN_ON(trans->transid == 0);
1659         btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1660         btrfs_set_header_nritems(lower, nritems + 1);
1661         btrfs_mark_buffer_dirty(lower);
1662         return 0;
1663 }
1664
1665 /*
1666  * split the node at the specified level in path in two.
1667  * The path is corrected to point to the appropriate node after the split
1668  *
1669  * Before splitting this tries to make some room in the node by pushing
1670  * left and right, if either one works, it returns right away.
1671  *
1672  * returns 0 on success and < 0 on failure
1673  */
1674 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1675                       *root, struct btrfs_path *path, int level)
1676 {
1677         u64 root_gen;
1678         struct extent_buffer *c;
1679         struct extent_buffer *split;
1680         struct btrfs_disk_key disk_key;
1681         int mid;
1682         int ret;
1683         int wret;
1684         u32 c_nritems;
1685
1686         c = path->nodes[level];
1687         WARN_ON(btrfs_header_generation(c) != trans->transid);
1688         if (c == root->node) {
1689                 /* trying to split the root, lets make a new one */
1690                 ret = insert_new_root(trans, root, path, level + 1);
1691                 if (ret)
1692                         return ret;
1693         } else {
1694                 ret = push_nodes_for_insert(trans, root, path, level);
1695                 c = path->nodes[level];
1696                 if (!ret && btrfs_header_nritems(c) <
1697                     BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1698                         return 0;
1699                 if (ret < 0)
1700                         return ret;
1701         }
1702
1703         c_nritems = btrfs_header_nritems(c);
1704         if (root->ref_cows)
1705                 root_gen = trans->transid;
1706         else
1707                 root_gen = 0;
1708
1709         btrfs_node_key(c, &disk_key, 0);
1710         split = btrfs_alloc_free_block(trans, root, root->nodesize,
1711                                          root->root_key.objectid,
1712                                          root_gen,
1713                                          btrfs_disk_key_objectid(&disk_key),
1714                                          level, c->start, 0);
1715         if (IS_ERR(split))
1716                 return PTR_ERR(split);
1717
1718         btrfs_set_header_flags(split, btrfs_header_flags(c));
1719         btrfs_set_header_level(split, btrfs_header_level(c));
1720         btrfs_set_header_bytenr(split, split->start);
1721         btrfs_set_header_generation(split, trans->transid);
1722         btrfs_set_header_owner(split, root->root_key.objectid);
1723         btrfs_set_header_flags(split, 0);
1724         write_extent_buffer(split, root->fs_info->fsid,
1725                             (unsigned long)btrfs_header_fsid(split),
1726                             BTRFS_FSID_SIZE);
1727         write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1728                             (unsigned long)btrfs_header_chunk_tree_uuid(split),
1729                             BTRFS_UUID_SIZE);
1730
1731         mid = (c_nritems + 1) / 2;
1732
1733         copy_extent_buffer(split, c,
1734                            btrfs_node_key_ptr_offset(0),
1735                            btrfs_node_key_ptr_offset(mid),
1736                            (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1737         btrfs_set_header_nritems(split, c_nritems - mid);
1738         btrfs_set_header_nritems(c, mid);
1739         ret = 0;
1740
1741         btrfs_mark_buffer_dirty(c);
1742         btrfs_mark_buffer_dirty(split);
1743
1744         btrfs_node_key(split, &disk_key, 0);
1745         wret = insert_ptr(trans, root, path, &disk_key, split->start,
1746                           path->slots[level + 1] + 1,
1747                           level + 1);
1748         if (wret)
1749                 ret = wret;
1750
1751         if (path->slots[level] >= mid) {
1752                 path->slots[level] -= mid;
1753                 btrfs_tree_unlock(c);
1754                 free_extent_buffer(c);
1755                 path->nodes[level] = split;
1756                 path->slots[level + 1] += 1;
1757         } else {
1758                 btrfs_tree_unlock(split);
1759                 free_extent_buffer(split);
1760         }
1761         return ret;
1762 }
1763
1764 /*
1765  * how many bytes are required to store the items in a leaf.  start
1766  * and nr indicate which items in the leaf to check.  This totals up the
1767  * space used both by the item structs and the item data
1768  */
1769 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1770 {
1771         int data_len;
1772         int nritems = btrfs_header_nritems(l);
1773         int end = min(nritems, start + nr) - 1;
1774
1775         if (!nr)
1776                 return 0;
1777         data_len = btrfs_item_end_nr(l, start);
1778         data_len = data_len - btrfs_item_offset_nr(l, end);
1779         data_len += sizeof(struct btrfs_item) * nr;
1780         WARN_ON(data_len < 0);
1781         return data_len;
1782 }
1783
1784 /*
1785  * The space between the end of the leaf items and
1786  * the start of the leaf data.  IOW, how much room
1787  * the leaf has left for both items and data
1788  */
1789 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1790 {
1791         int nritems = btrfs_header_nritems(leaf);
1792         int ret;
1793         ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1794         if (ret < 0) {
1795                 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1796                        ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1797                        leaf_space_used(leaf, 0, nritems), nritems);
1798         }
1799         return ret;
1800 }
1801
1802 /*
1803  * push some data in the path leaf to the right, trying to free up at
1804  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1805  *
1806  * returns 1 if the push failed because the other node didn't have enough
1807  * room, 0 if everything worked out and < 0 if there were major errors.
1808  */
1809 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1810                            *root, struct btrfs_path *path, int data_size,
1811                            int empty)
1812 {
1813         struct extent_buffer *left = path->nodes[0];
1814         struct extent_buffer *right;
1815         struct extent_buffer *upper;
1816         struct btrfs_disk_key disk_key;
1817         int slot;
1818         u32 i;
1819         int free_space;
1820         int push_space = 0;
1821         int push_items = 0;
1822         struct btrfs_item *item;
1823         u32 left_nritems;
1824         u32 nr;
1825         u32 right_nritems;
1826         u32 data_end;
1827         u32 this_item_size;
1828         int ret;
1829
1830         slot = path->slots[1];
1831         if (!path->nodes[1]) {
1832                 return 1;
1833         }
1834         upper = path->nodes[1];
1835         if (slot >= btrfs_header_nritems(upper) - 1)
1836                 return 1;
1837
1838         WARN_ON(!btrfs_tree_locked(path->nodes[1]));
1839
1840         right = read_node_slot(root, upper, slot + 1);
1841         btrfs_tree_lock(right);
1842         free_space = btrfs_leaf_free_space(root, right);
1843         if (free_space < data_size + sizeof(struct btrfs_item))
1844                 goto out_unlock;
1845
1846         /* cow and double check */
1847         ret = btrfs_cow_block(trans, root, right, upper,
1848                               slot + 1, &right);
1849         if (ret)
1850                 goto out_unlock;
1851
1852         free_space = btrfs_leaf_free_space(root, right);
1853         if (free_space < data_size + sizeof(struct btrfs_item))
1854                 goto out_unlock;
1855
1856         left_nritems = btrfs_header_nritems(left);
1857         if (left_nritems == 0)
1858                 goto out_unlock;
1859
1860         if (empty)
1861                 nr = 0;
1862         else
1863                 nr = 1;
1864
1865         i = left_nritems - 1;
1866         while (i >= nr) {
1867                 item = btrfs_item_nr(left, i);
1868
1869                 if (path->slots[0] == i)
1870                         push_space += data_size + sizeof(*item);
1871
1872                 if (!left->map_token) {
1873                         map_extent_buffer(left, (unsigned long)item,
1874                                         sizeof(struct btrfs_item),
1875                                         &left->map_token, &left->kaddr,
1876                                         &left->map_start, &left->map_len,
1877                                         KM_USER1);
1878                 }
1879
1880                 this_item_size = btrfs_item_size(left, item);
1881                 if (this_item_size + sizeof(*item) + push_space > free_space)
1882                         break;
1883                 push_items++;
1884                 push_space += this_item_size + sizeof(*item);
1885                 if (i == 0)
1886                         break;
1887                 i--;
1888         }
1889         if (left->map_token) {
1890                 unmap_extent_buffer(left, left->map_token, KM_USER1);
1891                 left->map_token = NULL;
1892         }
1893
1894         if (push_items == 0)
1895                 goto out_unlock;
1896
1897         if (!empty && push_items == left_nritems)
1898                 WARN_ON(1);
1899
1900         /* push left to right */
1901         right_nritems = btrfs_header_nritems(right);
1902
1903         push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1904         push_space -= leaf_data_end(root, left);
1905
1906         /* make room in the right data area */
1907         data_end = leaf_data_end(root, right);
1908         memmove_extent_buffer(right,
1909                               btrfs_leaf_data(right) + data_end - push_space,
1910                               btrfs_leaf_data(right) + data_end,
1911                               BTRFS_LEAF_DATA_SIZE(root) - data_end);
1912
1913         /* copy from the left data area */
1914         copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1915                      BTRFS_LEAF_DATA_SIZE(root) - push_space,
1916                      btrfs_leaf_data(left) + leaf_data_end(root, left),
1917                      push_space);
1918
1919         memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1920                               btrfs_item_nr_offset(0),
1921                               right_nritems * sizeof(struct btrfs_item));
1922
1923         /* copy the items from left to right */
1924         copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1925                    btrfs_item_nr_offset(left_nritems - push_items),
1926                    push_items * sizeof(struct btrfs_item));
1927
1928         /* update the item pointers */
1929         right_nritems += push_items;
1930         btrfs_set_header_nritems(right, right_nritems);
1931         push_space = BTRFS_LEAF_DATA_SIZE(root);
1932         for (i = 0; i < right_nritems; i++) {
1933                 item = btrfs_item_nr(right, i);
1934                 if (!right->map_token) {
1935                         map_extent_buffer(right, (unsigned long)item,
1936                                         sizeof(struct btrfs_item),
1937                                         &right->map_token, &right->kaddr,
1938                                         &right->map_start, &right->map_len,
1939                                         KM_USER1);
1940                 }
1941                 push_space -= btrfs_item_size(right, item);
1942                 btrfs_set_item_offset(right, item, push_space);
1943         }
1944
1945         if (right->map_token) {
1946                 unmap_extent_buffer(right, right->map_token, KM_USER1);
1947                 right->map_token = NULL;
1948         }
1949         left_nritems -= push_items;
1950         btrfs_set_header_nritems(left, left_nritems);
1951
1952         if (left_nritems)
1953                 btrfs_mark_buffer_dirty(left);
1954         btrfs_mark_buffer_dirty(right);
1955
1956         btrfs_item_key(right, &disk_key, 0);
1957         btrfs_set_node_key(upper, &disk_key, slot + 1);
1958         btrfs_mark_buffer_dirty(upper);
1959
1960         /* then fixup the leaf pointer in the path */
1961         if (path->slots[0] >= left_nritems) {
1962                 path->slots[0] -= left_nritems;
1963                 if (btrfs_header_nritems(path->nodes[0]) == 0)
1964                         clean_tree_block(trans, root, path->nodes[0]);
1965                 btrfs_tree_unlock(path->nodes[0]);
1966                 free_extent_buffer(path->nodes[0]);
1967                 path->nodes[0] = right;
1968                 path->slots[1] += 1;
1969         } else {
1970                 btrfs_tree_unlock(right);
1971                 free_extent_buffer(right);
1972         }
1973         return 0;
1974
1975 out_unlock:
1976         btrfs_tree_unlock(right);
1977         free_extent_buffer(right);
1978         return 1;
1979 }
1980
1981 /*
1982  * push some data in the path leaf to the left, trying to free up at
1983  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1984  */
1985 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1986                           *root, struct btrfs_path *path, int data_size,
1987                           int empty)
1988 {
1989         struct btrfs_disk_key disk_key;
1990         struct extent_buffer *right = path->nodes[0];
1991         struct extent_buffer *left;
1992         int slot;
1993         int i;
1994         int free_space;
1995         int push_space = 0;
1996         int push_items = 0;
1997         struct btrfs_item *item;
1998         u32 old_left_nritems;
1999         u32 right_nritems;
2000         u32 nr;
2001         int ret = 0;
2002         int wret;
2003         u32 this_item_size;
2004         u32 old_left_item_size;
2005
2006         slot = path->slots[1];
2007         if (slot == 0)
2008                 return 1;
2009         if (!path->nodes[1])
2010                 return 1;
2011
2012         right_nritems = btrfs_header_nritems(right);
2013         if (right_nritems == 0) {
2014                 return 1;
2015         }
2016
2017         WARN_ON(!btrfs_tree_locked(path->nodes[1]));
2018
2019         left = read_node_slot(root, path->nodes[1], slot - 1);
2020         btrfs_tree_lock(left);
2021         free_space = btrfs_leaf_free_space(root, left);
2022         if (free_space < data_size + sizeof(struct btrfs_item)) {
2023                 ret = 1;
2024                 goto out;
2025         }
2026
2027         /* cow and double check */
2028         ret = btrfs_cow_block(trans, root, left,
2029                               path->nodes[1], slot - 1, &left);
2030         if (ret) {
2031                 /* we hit -ENOSPC, but it isn't fatal here */
2032                 ret = 1;
2033                 goto out;
2034         }
2035
2036         free_space = btrfs_leaf_free_space(root, left);
2037         if (free_space < data_size + sizeof(struct btrfs_item)) {
2038                 ret = 1;
2039                 goto out;
2040         }
2041
2042         if (empty)
2043                 nr = right_nritems;
2044         else
2045                 nr = right_nritems - 1;
2046
2047         for (i = 0; i < nr; i++) {
2048                 item = btrfs_item_nr(right, i);
2049                 if (!right->map_token) {
2050                         map_extent_buffer(right, (unsigned long)item,
2051                                         sizeof(struct btrfs_item),
2052                                         &right->map_token, &right->kaddr,
2053                                         &right->map_start, &right->map_len,
2054                                         KM_USER1);
2055                 }
2056
2057                 if (path->slots[0] == i)
2058                         push_space += data_size + sizeof(*item);
2059
2060                 this_item_size = btrfs_item_size(right, item);
2061                 if (this_item_size + sizeof(*item) + push_space > free_space)
2062                         break;
2063
2064                 push_items++;
2065                 push_space += this_item_size + sizeof(*item);
2066         }
2067
2068         if (right->map_token) {
2069                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2070                 right->map_token = NULL;
2071         }
2072
2073         if (push_items == 0) {
2074                 ret = 1;
2075                 goto out;
2076         }
2077         if (!empty && push_items == btrfs_header_nritems(right))
2078                 WARN_ON(1);
2079
2080         /* push data from right to left */
2081         copy_extent_buffer(left, right,
2082                            btrfs_item_nr_offset(btrfs_header_nritems(left)),
2083                            btrfs_item_nr_offset(0),
2084                            push_items * sizeof(struct btrfs_item));
2085
2086         push_space = BTRFS_LEAF_DATA_SIZE(root) -
2087                      btrfs_item_offset_nr(right, push_items -1);
2088
2089         copy_extent_buffer(left, right, btrfs_leaf_data(left) +
2090                      leaf_data_end(root, left) - push_space,
2091                      btrfs_leaf_data(right) +
2092                      btrfs_item_offset_nr(right, push_items - 1),
2093                      push_space);
2094         old_left_nritems = btrfs_header_nritems(left);
2095         BUG_ON(old_left_nritems < 0);
2096
2097         old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
2098         for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
2099                 u32 ioff;
2100
2101                 item = btrfs_item_nr(left, i);
2102                 if (!left->map_token) {
2103                         map_extent_buffer(left, (unsigned long)item,
2104                                         sizeof(struct btrfs_item),
2105                                         &left->map_token, &left->kaddr,
2106                                         &left->map_start, &left->map_len,
2107                                         KM_USER1);
2108                 }
2109
2110                 ioff = btrfs_item_offset(left, item);
2111                 btrfs_set_item_offset(left, item,
2112                       ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
2113         }
2114         btrfs_set_header_nritems(left, old_left_nritems + push_items);
2115         if (left->map_token) {
2116                 unmap_extent_buffer(left, left->map_token, KM_USER1);
2117                 left->map_token = NULL;
2118         }
2119
2120         /* fixup right node */
2121         if (push_items > right_nritems) {
2122                 printk("push items %d nr %u\n", push_items, right_nritems);
2123                 WARN_ON(1);
2124         }
2125
2126         if (push_items < right_nritems) {
2127                 push_space = btrfs_item_offset_nr(right, push_items - 1) -
2128                                                   leaf_data_end(root, right);
2129                 memmove_extent_buffer(right, btrfs_leaf_data(right) +
2130                                       BTRFS_LEAF_DATA_SIZE(root) - push_space,
2131                                       btrfs_leaf_data(right) +
2132                                       leaf_data_end(root, right), push_space);
2133
2134                 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
2135                               btrfs_item_nr_offset(push_items),
2136                              (btrfs_header_nritems(right) - push_items) *
2137                              sizeof(struct btrfs_item));
2138         }
2139         right_nritems -= push_items;
2140         btrfs_set_header_nritems(right, right_nritems);
2141         push_space = BTRFS_LEAF_DATA_SIZE(root);
2142         for (i = 0; i < right_nritems; i++) {
2143                 item = btrfs_item_nr(right, i);
2144
2145                 if (!right->map_token) {
2146                         map_extent_buffer(right, (unsigned long)item,
2147                                         sizeof(struct btrfs_item),
2148                                         &right->map_token, &right->kaddr,
2149                                         &right->map_start, &right->map_len,
2150                                         KM_USER1);
2151                 }
2152
2153                 push_space = push_space - btrfs_item_size(right, item);
2154                 btrfs_set_item_offset(right, item, push_space);
2155         }
2156         if (right->map_token) {
2157                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2158                 right->map_token = NULL;
2159         }
2160
2161         btrfs_mark_buffer_dirty(left);
2162         if (right_nritems)
2163                 btrfs_mark_buffer_dirty(right);
2164
2165         btrfs_item_key(right, &disk_key, 0);
2166         wret = fixup_low_keys(trans, root, path, &disk_key, 1);
2167         if (wret)
2168                 ret = wret;
2169
2170         /* then fixup the leaf pointer in the path */
2171         if (path->slots[0] < push_items) {
2172                 path->slots[0] += old_left_nritems;
2173                 if (btrfs_header_nritems(path->nodes[0]) == 0)
2174                         clean_tree_block(trans, root, path->nodes[0]);
2175                 btrfs_tree_unlock(path->nodes[0]);
2176                 free_extent_buffer(path->nodes[0]);
2177                 path->nodes[0] = left;
2178                 path->slots[1] -= 1;
2179         } else {
2180                 btrfs_tree_unlock(left);
2181                 free_extent_buffer(left);
2182                 path->slots[0] -= push_items;
2183         }
2184         BUG_ON(path->slots[0] < 0);
2185         return ret;
2186 out:
2187         btrfs_tree_unlock(left);
2188         free_extent_buffer(left);
2189         return ret;
2190 }
2191
2192 /*
2193  * split the path's leaf in two, making sure there is at least data_size
2194  * available for the resulting leaf level of the path.
2195  *
2196  * returns 0 if all went well and < 0 on failure.
2197  */
2198 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
2199                       *root, struct btrfs_key *ins_key,
2200                       struct btrfs_path *path, int data_size, int extend)
2201 {
2202         u64 root_gen;
2203         struct extent_buffer *l;
2204         u32 nritems;
2205         int mid;
2206         int slot;
2207         struct extent_buffer *right;
2208         int space_needed = data_size + sizeof(struct btrfs_item);
2209         int data_copy_size;
2210         int rt_data_off;
2211         int i;
2212         int ret = 0;
2213         int wret;
2214         int double_split;
2215         int num_doubles = 0;
2216         struct btrfs_disk_key disk_key;
2217
2218         if (extend)
2219                 space_needed = data_size;
2220
2221         if (root->ref_cows)
2222                 root_gen = trans->transid;
2223         else
2224                 root_gen = 0;
2225
2226         /* first try to make some room by pushing left and right */
2227         if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
2228                 wret = push_leaf_right(trans, root, path, data_size, 0);
2229                 if (wret < 0) {
2230                         return wret;
2231                 }
2232                 if (wret) {
2233                         wret = push_leaf_left(trans, root, path, data_size, 0);
2234                         if (wret < 0)
2235                                 return wret;
2236                 }
2237                 l = path->nodes[0];
2238
2239                 /* did the pushes work? */
2240                 if (btrfs_leaf_free_space(root, l) >= space_needed)
2241                         return 0;
2242         }
2243
2244         if (!path->nodes[1]) {
2245                 ret = insert_new_root(trans, root, path, 1);
2246                 if (ret)
2247                         return ret;
2248         }
2249 again:
2250         double_split = 0;
2251         l = path->nodes[0];
2252         slot = path->slots[0];
2253         nritems = btrfs_header_nritems(l);
2254         mid = (nritems + 1)/ 2;
2255
2256         btrfs_item_key(l, &disk_key, 0);
2257
2258         right = btrfs_alloc_free_block(trans, root, root->leafsize,
2259                                          root->root_key.objectid,
2260                                          root_gen, disk_key.objectid, 0,
2261                                          l->start, 0);
2262         if (IS_ERR(right)) {
2263                 BUG_ON(1);
2264                 return PTR_ERR(right);
2265         }
2266
2267         memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2268         btrfs_set_header_bytenr(right, right->start);
2269         btrfs_set_header_generation(right, trans->transid);
2270         btrfs_set_header_owner(right, root->root_key.objectid);
2271         btrfs_set_header_level(right, 0);
2272         write_extent_buffer(right, root->fs_info->fsid,
2273                             (unsigned long)btrfs_header_fsid(right),
2274                             BTRFS_FSID_SIZE);
2275
2276         write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2277                             (unsigned long)btrfs_header_chunk_tree_uuid(right),
2278                             BTRFS_UUID_SIZE);
2279         if (mid <= slot) {
2280                 if (nritems == 1 ||
2281                     leaf_space_used(l, mid, nritems - mid) + space_needed >
2282                         BTRFS_LEAF_DATA_SIZE(root)) {
2283                         if (slot >= nritems) {
2284                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2285                                 btrfs_set_header_nritems(right, 0);
2286                                 wret = insert_ptr(trans, root, path,
2287                                                   &disk_key, right->start,
2288                                                   path->slots[1] + 1, 1);
2289                                 if (wret)
2290                                         ret = wret;
2291
2292                                 btrfs_tree_unlock(path->nodes[0]);
2293                                 free_extent_buffer(path->nodes[0]);
2294                                 path->nodes[0] = right;
2295                                 path->slots[0] = 0;
2296                                 path->slots[1] += 1;
2297                                 btrfs_mark_buffer_dirty(right);
2298                                 return ret;
2299                         }
2300                         mid = slot;
2301                         if (mid != nritems &&
2302                             leaf_space_used(l, mid, nritems - mid) +
2303                             space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2304                                 double_split = 1;
2305                         }
2306                 }
2307         } else {
2308                 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2309                         BTRFS_LEAF_DATA_SIZE(root)) {
2310                         if (!extend && slot == 0) {
2311                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2312                                 btrfs_set_header_nritems(right, 0);
2313                                 wret = insert_ptr(trans, root, path,
2314                                                   &disk_key,
2315                                                   right->start,
2316                                                   path->slots[1], 1);
2317                                 if (wret)
2318                                         ret = wret;
2319                                 btrfs_tree_unlock(path->nodes[0]);
2320                                 free_extent_buffer(path->nodes[0]);
2321                                 path->nodes[0] = right;
2322                                 path->slots[0] = 0;
2323                                 if (path->slots[1] == 0) {
2324                                         wret = fixup_low_keys(trans, root,
2325                                                    path, &disk_key, 1);
2326                                         if (wret)
2327                                                 ret = wret;
2328                                 }
2329                                 btrfs_mark_buffer_dirty(right);
2330                                 return ret;
2331                         } else if (extend && slot == 0) {
2332                                 mid = 1;
2333                         } else {
2334                                 mid = slot;
2335                                 if (mid != nritems &&
2336                                     leaf_space_used(l, mid, nritems - mid) +
2337                                     space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2338                                         double_split = 1;
2339                                 }
2340                         }
2341                 }
2342         }
2343         nritems = nritems - mid;
2344         btrfs_set_header_nritems(right, nritems);
2345         data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2346
2347         copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2348                            btrfs_item_nr_offset(mid),
2349                            nritems * sizeof(struct btrfs_item));
2350
2351         copy_extent_buffer(right, l,
2352                      btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2353                      data_copy_size, btrfs_leaf_data(l) +
2354                      leaf_data_end(root, l), data_copy_size);
2355
2356         rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2357                       btrfs_item_end_nr(l, mid);
2358
2359         for (i = 0; i < nritems; i++) {
2360                 struct btrfs_item *item = btrfs_item_nr(right, i);
2361                 u32 ioff;
2362
2363                 if (!right->map_token) {
2364                         map_extent_buffer(right, (unsigned long)item,
2365                                         sizeof(struct btrfs_item),
2366                                         &right->map_token, &right->kaddr,
2367                                         &right->map_start, &right->map_len,
2368                                         KM_USER1);
2369                 }
2370
2371                 ioff = btrfs_item_offset(right, item);
2372                 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2373         }
2374
2375         if (right->map_token) {
2376                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2377                 right->map_token = NULL;
2378         }
2379
2380         btrfs_set_header_nritems(l, mid);
2381         ret = 0;
2382         btrfs_item_key(right, &disk_key, 0);
2383         wret = insert_ptr(trans, root, path, &disk_key, right->start,
2384                           path->slots[1] + 1, 1);
2385         if (wret)
2386                 ret = wret;
2387
2388         btrfs_mark_buffer_dirty(right);
2389         btrfs_mark_buffer_dirty(l);
2390         BUG_ON(path->slots[0] != slot);
2391
2392         if (mid <= slot) {
2393                 btrfs_tree_unlock(path->nodes[0]);
2394                 free_extent_buffer(path->nodes[0]);
2395                 path->nodes[0] = right;
2396                 path->slots[0] -= mid;
2397                 path->slots[1] += 1;
2398         } else {
2399                 btrfs_tree_unlock(right);
2400                 free_extent_buffer(right);
2401         }
2402
2403         BUG_ON(path->slots[0] < 0);
2404
2405         if (double_split) {
2406                 BUG_ON(num_doubles != 0);
2407                 num_doubles++;
2408                 goto again;
2409         }
2410         return ret;
2411 }
2412
2413 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2414                         struct btrfs_root *root,
2415                         struct btrfs_path *path,
2416                         u32 new_size, int from_end)
2417 {
2418         int ret = 0;
2419         int slot;
2420         int slot_orig;
2421         struct extent_buffer *leaf;
2422         struct btrfs_item *item;
2423         u32 nritems;
2424         unsigned int data_end;
2425         unsigned int old_data_start;
2426         unsigned int old_size;
2427         unsigned int size_diff;
2428         int i;
2429
2430         slot_orig = path->slots[0];
2431         leaf = path->nodes[0];
2432         slot = path->slots[0];
2433
2434         old_size = btrfs_item_size_nr(leaf, slot);
2435         if (old_size == new_size)
2436                 return 0;
2437
2438         nritems = btrfs_header_nritems(leaf);
2439         data_end = leaf_data_end(root, leaf);
2440
2441         old_data_start = btrfs_item_offset_nr(leaf, slot);
2442
2443         size_diff = old_size - new_size;
2444
2445         BUG_ON(slot < 0);
2446         BUG_ON(slot >= nritems);
2447
2448         /*
2449          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2450          */
2451         /* first correct the data pointers */
2452         for (i = slot; i < nritems; i++) {
2453                 u32 ioff;
2454                 item = btrfs_item_nr(leaf, i);
2455
2456                 if (!leaf->map_token) {
2457                         map_extent_buffer(leaf, (unsigned long)item,
2458                                         sizeof(struct btrfs_item),
2459                                         &leaf->map_token, &leaf->kaddr,
2460                                         &leaf->map_start, &leaf->map_len,
2461                                         KM_USER1);
2462                 }
2463
2464                 ioff = btrfs_item_offset(leaf, item);
2465                 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2466         }
2467
2468         if (leaf->map_token) {
2469                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2470                 leaf->map_token = NULL;
2471         }
2472
2473         /* shift the data */
2474         if (from_end) {
2475                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2476                               data_end + size_diff, btrfs_leaf_data(leaf) +
2477                               data_end, old_data_start + new_size - data_end);
2478         } else {
2479                 struct btrfs_disk_key disk_key;
2480                 u64 offset;
2481
2482                 btrfs_item_key(leaf, &disk_key, slot);
2483
2484                 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2485                         unsigned long ptr;
2486                         struct btrfs_file_extent_item *fi;
2487
2488                         fi = btrfs_item_ptr(leaf, slot,
2489                                             struct btrfs_file_extent_item);
2490                         fi = (struct btrfs_file_extent_item *)(
2491                              (unsigned long)fi - size_diff);
2492
2493                         if (btrfs_file_extent_type(leaf, fi) ==
2494                             BTRFS_FILE_EXTENT_INLINE) {
2495                                 ptr = btrfs_item_ptr_offset(leaf, slot);
2496                                 memmove_extent_buffer(leaf, ptr,
2497                                         (unsigned long)fi,
2498                                         offsetof(struct btrfs_file_extent_item,
2499                                                  disk_bytenr));
2500                         }
2501                 }
2502
2503                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2504                               data_end + size_diff, btrfs_leaf_data(leaf) +
2505                               data_end, old_data_start - data_end);
2506
2507                 offset = btrfs_disk_key_offset(&disk_key);
2508                 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2509                 btrfs_set_item_key(leaf, &disk_key, slot);
2510                 if (slot == 0)
2511                         fixup_low_keys(trans, root, path, &disk_key, 1);
2512         }
2513
2514         item = btrfs_item_nr(leaf, slot);
2515         btrfs_set_item_size(leaf, item, new_size);
2516         btrfs_mark_buffer_dirty(leaf);
2517
2518         ret = 0;
2519         if (btrfs_leaf_free_space(root, leaf) < 0) {
2520                 btrfs_print_leaf(root, leaf);
2521                 BUG();
2522         }
2523         return ret;
2524 }
2525
2526 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2527                       struct btrfs_root *root, struct btrfs_path *path,
2528                       u32 data_size)
2529 {
2530         int ret = 0;
2531         int slot;
2532         int slot_orig;
2533         struct extent_buffer *leaf;
2534         struct btrfs_item *item;
2535         u32 nritems;
2536         unsigned int data_end;
2537         unsigned int old_data;
2538         unsigned int old_size;
2539         int i;
2540
2541         slot_orig = path->slots[0];
2542         leaf = path->nodes[0];
2543
2544         nritems = btrfs_header_nritems(leaf);
2545         data_end = leaf_data_end(root, leaf);
2546
2547         if (btrfs_leaf_free_space(root, leaf) < data_size) {
2548                 btrfs_print_leaf(root, leaf);
2549                 BUG();
2550         }
2551         slot = path->slots[0];
2552         old_data = btrfs_item_end_nr(leaf, slot);
2553
2554         BUG_ON(slot < 0);
2555         if (slot >= nritems) {
2556                 btrfs_print_leaf(root, leaf);
2557                 printk("slot %d too large, nritems %d\n", slot, nritems);
2558                 BUG_ON(1);
2559         }
2560
2561         /*
2562          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2563          */
2564         /* first correct the data pointers */
2565         for (i = slot; i < nritems; i++) {
2566                 u32 ioff;
2567                 item = btrfs_item_nr(leaf, i);
2568
2569                 if (!leaf->map_token) {
2570                         map_extent_buffer(leaf, (unsigned long)item,
2571                                         sizeof(struct btrfs_item),
2572                                         &leaf->map_token, &leaf->kaddr,
2573                                         &leaf->map_start, &leaf->map_len,
2574                                         KM_USER1);
2575                 }
2576                 ioff = btrfs_item_offset(leaf, item);
2577                 btrfs_set_item_offset(leaf, item, ioff - data_size);
2578         }
2579
2580         if (leaf->map_token) {
2581                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2582                 leaf->map_token = NULL;
2583         }
2584
2585         /* shift the data */
2586         memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2587                       data_end - data_size, btrfs_leaf_data(leaf) +
2588                       data_end, old_data - data_end);
2589
2590         data_end = old_data;
2591         old_size = btrfs_item_size_nr(leaf, slot);
2592         item = btrfs_item_nr(leaf, slot);
2593         btrfs_set_item_size(leaf, item, old_size + data_size);
2594         btrfs_mark_buffer_dirty(leaf);
2595
2596         ret = 0;
2597         if (btrfs_leaf_free_space(root, leaf) < 0) {
2598                 btrfs_print_leaf(root, leaf);
2599                 BUG();
2600         }
2601         return ret;
2602 }
2603
2604 /*
2605  * Given a key and some data, insert an item into the tree.
2606  * This does all the path init required, making room in the tree if needed.
2607  */
2608 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2609                             struct btrfs_root *root,
2610                             struct btrfs_path *path,
2611                             struct btrfs_key *cpu_key, u32 *data_size,
2612                             int nr)
2613 {
2614         struct extent_buffer *leaf;
2615         struct btrfs_item *item;
2616         int ret = 0;
2617         int slot;
2618         int slot_orig;
2619         int i;
2620         u32 nritems;
2621         u32 total_size = 0;
2622         u32 total_data = 0;
2623         unsigned int data_end;
2624         struct btrfs_disk_key disk_key;
2625
2626         for (i = 0; i < nr; i++) {
2627                 total_data += data_size[i];
2628         }
2629
2630         total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2631         ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2632         if (ret == 0) {
2633                 return -EEXIST;
2634         }
2635         if (ret < 0)
2636                 goto out;
2637
2638         slot_orig = path->slots[0];
2639         leaf = path->nodes[0];
2640
2641         nritems = btrfs_header_nritems(leaf);
2642         data_end = leaf_data_end(root, leaf);
2643
2644         if (btrfs_leaf_free_space(root, leaf) <
2645             sizeof(struct btrfs_item) + total_size) {
2646                 btrfs_print_leaf(root, leaf);
2647                 printk("not enough freespace need %u have %d\n",
2648                        total_size, btrfs_leaf_free_space(root, leaf));
2649                 BUG();
2650         }
2651
2652         slot = path->slots[0];
2653         BUG_ON(slot < 0);
2654
2655         if (slot != nritems) {
2656                 int i;
2657                 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2658
2659                 if (old_data < data_end) {
2660                         btrfs_print_leaf(root, leaf);
2661                         printk("slot %d old_data %d data_end %d\n",
2662                                slot, old_data, data_end);
2663                         BUG_ON(1);
2664                 }
2665                 /*
2666                  * item0..itemN ... dataN.offset..dataN.size .. data0.size
2667                  */
2668                 /* first correct the data pointers */
2669                 WARN_ON(leaf->map_token);
2670                 for (i = slot; i < nritems; i++) {
2671                         u32 ioff;
2672
2673                         item = btrfs_item_nr(leaf, i);
2674                         if (!leaf->map_token) {
2675                                 map_extent_buffer(leaf, (unsigned long)item,
2676                                         sizeof(struct btrfs_item),
2677                                         &leaf->map_token, &leaf->kaddr,
2678                                         &leaf->map_start, &leaf->map_len,
2679                                         KM_USER1);
2680                         }
2681
2682                         ioff = btrfs_item_offset(leaf, item);
2683                         btrfs_set_item_offset(leaf, item, ioff - total_data);
2684                 }
2685                 if (leaf->map_token) {
2686                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2687                         leaf->map_token = NULL;
2688                 }
2689
2690                 /* shift the items */
2691                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2692                               btrfs_item_nr_offset(slot),
2693                               (nritems - slot) * sizeof(struct btrfs_item));
2694
2695                 /* shift the data */
2696                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2697                               data_end - total_data, btrfs_leaf_data(leaf) +
2698                               data_end, old_data - data_end);
2699                 data_end = old_data;
2700         }
2701
2702         /* setup the item for the new data */
2703         for (i = 0; i < nr; i++) {
2704                 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2705                 btrfs_set_item_key(leaf, &disk_key, slot + i);
2706                 item = btrfs_item_nr(leaf, slot + i);
2707                 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2708                 data_end -= data_size[i];
2709                 btrfs_set_item_size(leaf, item, data_size[i]);
2710         }
2711         btrfs_set_header_nritems(leaf, nritems + nr);
2712         btrfs_mark_buffer_dirty(leaf);
2713
2714         ret = 0;
2715         if (slot == 0) {
2716                 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2717                 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2718         }
2719
2720         if (btrfs_leaf_free_space(root, leaf) < 0) {
2721                 btrfs_print_leaf(root, leaf);
2722                 BUG();
2723         }
2724 out:
2725         return ret;
2726 }
2727
2728 /*
2729  * Given a key and some data, insert an item into the tree.
2730  * This does all the path init required, making room in the tree if needed.
2731  */
2732 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2733                       *root, struct btrfs_key *cpu_key, void *data, u32
2734                       data_size)
2735 {
2736         int ret = 0;
2737         struct btrfs_path *path;
2738         struct extent_buffer *leaf;
2739         unsigned long ptr;
2740
2741         path = btrfs_alloc_path();
2742         BUG_ON(!path);
2743         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2744         if (!ret) {
2745                 leaf = path->nodes[0];
2746                 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2747                 write_extent_buffer(leaf, data, ptr, data_size);
2748                 btrfs_mark_buffer_dirty(leaf);
2749         }
2750         btrfs_free_path(path);
2751         return ret;
2752 }
2753
2754 /*
2755  * delete the pointer from a given node.
2756  *
2757  * If the delete empties a node, the node is removed from the tree,
2758  * continuing all the way the root if required.  The root is converted into
2759  * a leaf if all the nodes are emptied.
2760  */
2761 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2762                    struct btrfs_path *path, int level, int slot)
2763 {
2764         struct extent_buffer *parent = path->nodes[level];
2765         u32 nritems;
2766         int ret = 0;
2767         int wret;
2768
2769         nritems = btrfs_header_nritems(parent);
2770         if (slot != nritems -1) {
2771                 memmove_extent_buffer(parent,
2772                               btrfs_node_key_ptr_offset(slot),
2773                               btrfs_node_key_ptr_offset(slot + 1),
2774                               sizeof(struct btrfs_key_ptr) *
2775                               (nritems - slot - 1));
2776         }
2777         nritems--;
2778         btrfs_set_header_nritems(parent, nritems);
2779         if (nritems == 0 && parent == root->node) {
2780                 BUG_ON(btrfs_header_level(root->node) != 1);
2781                 /* just turn the root into a leaf and break */
2782                 btrfs_set_header_level(root->node, 0);
2783         } else if (slot == 0) {
2784                 struct btrfs_disk_key disk_key;
2785
2786                 btrfs_node_key(parent, &disk_key, 0);
2787                 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2788                 if (wret)
2789                         ret = wret;
2790         }
2791         btrfs_mark_buffer_dirty(parent);
2792         return ret;
2793 }
2794
2795 /*
2796  * delete the item at the leaf level in path.  If that empties
2797  * the leaf, remove it from the tree
2798  */
2799 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2800                     struct btrfs_path *path, int slot, int nr)
2801 {
2802         struct extent_buffer *leaf;
2803         struct btrfs_item *item;
2804         int last_off;
2805         int dsize = 0;
2806         int ret = 0;
2807         int wret;
2808         int i;
2809         u32 nritems;
2810
2811         leaf = path->nodes[0];
2812         last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2813
2814         for (i = 0; i < nr; i++)
2815                 dsize += btrfs_item_size_nr(leaf, slot + i);
2816
2817         nritems = btrfs_header_nritems(leaf);
2818
2819         if (slot + nr != nritems) {
2820                 int i;
2821                 int data_end = leaf_data_end(root, leaf);
2822
2823                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2824                               data_end + dsize,
2825                               btrfs_leaf_data(leaf) + data_end,
2826                               last_off - data_end);
2827
2828                 for (i = slot + nr; i < nritems; i++) {
2829                         u32 ioff;
2830
2831                         item = btrfs_item_nr(leaf, i);
2832                         if (!leaf->map_token) {
2833                                 map_extent_buffer(leaf, (unsigned long)item,
2834                                         sizeof(struct btrfs_item),
2835                                         &leaf->map_token, &leaf->kaddr,
2836                                         &leaf->map_start, &leaf->map_len,
2837                                         KM_USER1);
2838                         }
2839                         ioff = btrfs_item_offset(leaf, item);
2840                         btrfs_set_item_offset(leaf, item, ioff + dsize);
2841                 }
2842
2843                 if (leaf->map_token) {
2844                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2845                         leaf->map_token = NULL;
2846                 }
2847
2848                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2849                               btrfs_item_nr_offset(slot + nr),
2850                               sizeof(struct btrfs_item) *
2851                               (nritems - slot - nr));
2852         }
2853         btrfs_set_header_nritems(leaf, nritems - nr);
2854         nritems -= nr;
2855
2856         /* delete the leaf if we've emptied it */
2857         if (nritems == 0) {
2858                 if (leaf == root->node) {
2859                         btrfs_set_header_level(leaf, 0);
2860                 } else {
2861                         u64 root_gen = btrfs_header_generation(path->nodes[1]);
2862                         wret = del_ptr(trans, root, path, 1, path->slots[1]);
2863                         if (wret)
2864                                 ret = wret;
2865                         wret = btrfs_free_extent(trans, root,
2866                                          leaf->start, leaf->len,
2867                                          btrfs_header_owner(path->nodes[1]),
2868                                          root_gen, 0, 0, 1);
2869                         if (wret)
2870                                 ret = wret;
2871                 }
2872         } else {
2873                 int used = leaf_space_used(leaf, 0, nritems);
2874                 if (slot == 0) {
2875                         struct btrfs_disk_key disk_key;
2876
2877                         btrfs_item_key(leaf, &disk_key, 0);
2878                         wret = fixup_low_keys(trans, root, path,
2879                                               &disk_key, 1);
2880                         if (wret)
2881                                 ret = wret;
2882                 }
2883
2884                 /* delete the leaf if it is mostly empty */
2885                 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2886                         /* push_leaf_left fixes the path.
2887                          * make sure the path still points to our leaf
2888                          * for possible call to del_ptr below
2889                          */
2890                         slot = path->slots[1];
2891                         extent_buffer_get(leaf);
2892
2893                         wret = push_leaf_left(trans, root, path, 1, 1);
2894                         if (wret < 0 && wret != -ENOSPC)
2895                                 ret = wret;
2896
2897                         if (path->nodes[0] == leaf &&
2898                             btrfs_header_nritems(leaf)) {
2899                                 wret = push_leaf_right(trans, root, path, 1, 1);
2900                                 if (wret < 0 && wret != -ENOSPC)
2901                                         ret = wret;
2902                         }
2903
2904                         if (btrfs_header_nritems(leaf) == 0) {
2905                                 u64 root_gen;
2906                                 u64 bytenr = leaf->start;
2907                                 u32 blocksize = leaf->len;
2908
2909                                 root_gen = btrfs_header_generation(
2910                                                            path->nodes[1]);
2911
2912                                 wret = del_ptr(trans, root, path, 1, slot);
2913                                 if (wret)
2914                                         ret = wret;
2915
2916                                 free_extent_buffer(leaf);
2917                                 wret = btrfs_free_extent(trans, root, bytenr,
2918                                              blocksize,
2919                                              btrfs_header_owner(path->nodes[1]),
2920                                              root_gen, 0, 0, 1);
2921                                 if (wret)
2922                                         ret = wret;
2923                         } else {
2924                                 /* if we're still in the path, make sure
2925                                  * we're dirty.  Otherwise, one of the
2926                                  * push_leaf functions must have already
2927                                  * dirtied this buffer
2928                                  */
2929                                 if (path->nodes[0] == leaf)
2930                                         btrfs_mark_buffer_dirty(leaf);
2931                                 free_extent_buffer(leaf);
2932                         }
2933                 } else {
2934                         btrfs_mark_buffer_dirty(leaf);
2935                 }
2936         }
2937         return ret;
2938 }
2939
2940 /*
2941  * search the tree again to find a leaf with lesser keys
2942  * returns 0 if it found something or 1 if there are no lesser leaves.
2943  * returns < 0 on io errors.
2944  */
2945 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2946 {
2947         struct btrfs_key key;
2948         struct btrfs_disk_key found_key;
2949         int ret;
2950
2951         btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
2952
2953         if (key.offset > 0)
2954                 key.offset--;
2955         else if (key.type > 0)
2956                 key.type--;
2957         else if (key.objectid > 0)
2958                 key.objectid--;
2959         else
2960                 return 1;
2961
2962         btrfs_release_path(root, path);
2963         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2964         if (ret < 0)
2965                 return ret;
2966         btrfs_item_key(path->nodes[0], &found_key, 0);
2967         ret = comp_keys(&found_key, &key);
2968         if (ret < 0)
2969                 return 0;
2970         return 1;
2971 }
2972
2973 /*
2974  * search the tree again to find a leaf with greater keys
2975  * returns 0 if it found something or 1 if there are no greater leaves.
2976  * returns < 0 on io errors.
2977  */
2978 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2979 {
2980         int slot;
2981         int level = 1;
2982         struct extent_buffer *c;
2983         struct extent_buffer *next = NULL;
2984         struct btrfs_key key;
2985         u32 nritems;
2986         int ret;
2987
2988         nritems = btrfs_header_nritems(path->nodes[0]);
2989         if (nritems == 0) {
2990                 return 1;
2991         }
2992
2993         btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
2994
2995         btrfs_release_path(root, path);
2996         path->keep_locks = 1;
2997         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2998         path->keep_locks = 0;
2999
3000         if (ret < 0)
3001                 return ret;
3002
3003         nritems = btrfs_header_nritems(path->nodes[0]);
3004         /*
3005          * by releasing the path above we dropped all our locks.  A balance
3006          * could have added more items next to the key that used to be
3007          * at the very end of the block.  So, check again here and
3008          * advance the path if there are now more items available.
3009          */
3010         if (nritems > 0 && path->slots[0] < nritems - 1) {
3011                 path->slots[0]++;
3012                 goto done;
3013         }
3014
3015         while(level < BTRFS_MAX_LEVEL) {
3016                 if (!path->nodes[level])
3017                         return 1;
3018
3019                 slot = path->slots[level] + 1;
3020                 c = path->nodes[level];
3021                 if (slot >= btrfs_header_nritems(c)) {
3022                         level++;
3023                         if (level == BTRFS_MAX_LEVEL) {
3024                                 return 1;
3025                         }
3026                         continue;
3027                 }
3028
3029                 if (next) {
3030                         btrfs_tree_unlock(next);
3031                         free_extent_buffer(next);
3032                 }
3033
3034                 if (level == 1 && path->locks[1] && path->reada)
3035                         reada_for_search(root, path, level, slot, 0);
3036
3037                 next = read_node_slot(root, c, slot);
3038                 if (!path->skip_locking) {
3039                         WARN_ON(!btrfs_tree_locked(c));
3040                         btrfs_tree_lock(next);
3041                 }
3042                 break;
3043         }
3044         path->slots[level] = slot;
3045         while(1) {
3046                 level--;
3047                 c = path->nodes[level];
3048                 if (path->locks[level])
3049                         btrfs_tree_unlock(c);
3050                 free_extent_buffer(c);
3051                 path->nodes[level] = next;
3052                 path->slots[level] = 0;
3053                 if (!path->skip_locking)
3054                         path->locks[level] = 1;
3055                 if (!level)
3056                         break;
3057                 if (level == 1 && path->locks[1] && path->reada)
3058                         reada_for_search(root, path, level, slot, 0);
3059                 next = read_node_slot(root, next, 0);
3060                 if (!path->skip_locking) {
3061                         WARN_ON(!btrfs_tree_locked(path->nodes[level]));
3062                         btrfs_tree_lock(next);
3063                 }
3064         }
3065 done:
3066         unlock_up(path, 0, 1);
3067         return 0;
3068 }
3069
3070 int btrfs_previous_item(struct btrfs_root *root,
3071                         struct btrfs_path *path, u64 min_objectid,
3072                         int type)
3073 {
3074         struct btrfs_key found_key;
3075         struct extent_buffer *leaf;
3076         int ret;
3077
3078         while(1) {
3079                 if (path->slots[0] == 0) {
3080                         ret = btrfs_prev_leaf(root, path);
3081                         if (ret != 0)
3082                                 return ret;
3083                 } else {
3084                         path->slots[0]--;
3085                 }
3086                 leaf = path->nodes[0];
3087                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3088                 if (found_key.type == type)
3089                         return 0;
3090         }
3091         return 1;
3092 }
3093