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
  67         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
  68                 p->slots[i] = 0;
  69                 if (!p->nodes[i])
  70                         continue;
  71                 if (p->locks[i]) {
  72                         btrfs_tree_unlock(p->nodes[i]);
  73                         p->locks[i] = 0;
  74                 }
  75                 free_extent_buffer(p->nodes[i]);
  76                 p->nodes[i] = NULL;
  77         }
  78 }
  79
  80 struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
  81 {
  82         struct extent_buffer *eb;
  83         spin_lock(&root->node_lock);
  84         eb = root->node;
  85         extent_buffer_get(eb);
  86         spin_unlock(&root->node_lock);
  87         return eb;
  88 }
  89
  90 struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
  91 {
  92         struct extent_buffer *eb;
  93
  94         while(1) {
  95                 eb = btrfs_root_node(root);
  96                 btrfs_tree_lock(eb);
  97
  98                 spin_lock(&root->node_lock);
  99                 if (eb == root->node) {
 100                         spin_unlock(&root->node_lock);
 101                         break;
 102                 }
 103                 spin_unlock(&root->node_lock);
 104
 105                 btrfs_tree_unlock(eb);
 106                 free_extent_buffer(eb);
 107         }
 108         return eb;
 109 }
 110
 111 static void add_root_to_dirty_list(struct btrfs_root *root)
 112 {
 113         if (root->track_dirty && list_empty(&root->dirty_list)) {
 114                 list_add(&root->dirty_list,
 115                          &root->fs_info->dirty_cowonly_roots);
 116         }
 117 }
 118
 119 int btrfs_copy_root(struct btrfs_trans_handle *trans,
 120                       struct btrfs_root *root,
 121                       struct extent_buffer *buf,
 122                       struct extent_buffer **cow_ret, u64 new_root_objectid)
 123 {
 124         struct extent_buffer *cow;
 125         u32 nritems;
 126         int ret = 0;
 127         int level;
 128         struct btrfs_key first_key;
 129         struct btrfs_root *new_root;
 130
 131         new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
 132         if (!new_root)
 133                 return -ENOMEM;
 134
 135         memcpy(new_root, root, sizeof(*new_root));
 136         new_root->root_key.objectid = new_root_objectid;
 137
 138         WARN_ON(root->ref_cows && trans->transid !=
 139                 root->fs_info->running_transaction->transid);
 140         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 141
 142         level = btrfs_header_level(buf);
 143         nritems = btrfs_header_nritems(buf);
 144         if (nritems) {
 145                 if (level == 0)
 146                         btrfs_item_key_to_cpu(buf, &first_key, 0);
 147                 else
 148                         btrfs_node_key_to_cpu(buf, &first_key, 0);
 149         } else {
 150                 first_key.objectid = 0;
 151         }
 152         cow = btrfs_alloc_free_block(trans, new_root, buf->len,
 153                                        new_root_objectid,
 154                                        trans->transid, first_key.objectid,
 155                                        level, buf->start, 0);
 156         if (IS_ERR(cow)) {
 157                 kfree(new_root);
 158                 return PTR_ERR(cow);
 159         }
 160
 161         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 162         btrfs_set_header_bytenr(cow, cow->start);
 163         btrfs_set_header_generation(cow, trans->transid);
 164         btrfs_set_header_owner(cow, new_root_objectid);
 165         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 166
 167         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 168         ret = btrfs_inc_ref(trans, new_root, buf);
 169         kfree(new_root);
 170
 171         if (ret)
 172                 return ret;
 173
 174         btrfs_mark_buffer_dirty(cow);
 175         *cow_ret = cow;
 176         return 0;
 177 }
 178
 179 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 180                              struct btrfs_root *root,
 181                              struct extent_buffer *buf,
 182                              struct extent_buffer *parent, int parent_slot,
 183                              struct extent_buffer **cow_ret,
 184                              u64 search_start, u64 empty_size)
 185 {
 186         u64 root_gen;
 187         struct extent_buffer *cow;
 188         u32 nritems;
 189         int ret = 0;
 190         int different_trans = 0;
 191         int level;
 192         int unlock_orig = 0;
 193         struct btrfs_key first_key;
 194
 195         if (*cow_ret == buf)
 196                 unlock_orig = 1;
 197
 198         WARN_ON(!btrfs_tree_locked(buf));
 199
 200         if (root->ref_cows) {
 201                 root_gen = trans->transid;
 202         } else {
 203                 root_gen = 0;
 204         }
 205         WARN_ON(root->ref_cows && trans->transid !=
 206                 root->fs_info->running_transaction->transid);
 207         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 208
 209         level = btrfs_header_level(buf);
 210         nritems = btrfs_header_nritems(buf);
 211         if (nritems) {
 212                 if (level == 0)
 213                         btrfs_item_key_to_cpu(buf, &first_key, 0);
 214                 else
 215                         btrfs_node_key_to_cpu(buf, &first_key, 0);
 216         } else {
 217                 first_key.objectid = 0;
 218         }
 219         cow = btrfs_alloc_free_block(trans, root, buf->len,
 220                                      root->root_key.objectid,
 221                                      root_gen, first_key.objectid, level,
 222                                      search_start, empty_size);
 223         if (IS_ERR(cow))
 224                 return PTR_ERR(cow);
 225
 226         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 227         btrfs_set_header_bytenr(cow, cow->start);
 228         btrfs_set_header_generation(cow, trans->transid);
 229         btrfs_set_header_owner(cow, root->root_key.objectid);
 230         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
 231
 232         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 233         if (btrfs_header_generation(buf) != trans->transid) {
 234                 different_trans = 1;
 235                 ret = btrfs_inc_ref(trans, root, buf);
 236                 if (ret)
 237                         return ret;
 238         } else {
 239                 clean_tree_block(trans, root, buf);
 240         }
 241
 242         if (buf == root->node) {
 243                 WARN_ON(parent && parent != buf);
 244                 root_gen = btrfs_header_generation(buf);
 245
 246                 spin_lock(&root->node_lock);
 247                 root->node = cow;
 248                 extent_buffer_get(cow);
 249                 spin_unlock(&root->node_lock);
 250
 251                 if (buf != root->commit_root) {
 252                         btrfs_free_extent(trans, root, buf->start,
 253                                           buf->len, root->root_key.objectid,
 254                                           root_gen, 0, 0, 1);
 255                 }
 256                 free_extent_buffer(buf);
 257                 add_root_to_dirty_list(root);
 258         } else {
 259                 root_gen = btrfs_header_generation(parent);
 260                 btrfs_set_node_blockptr(parent, parent_slot,
 261                                         cow->start);
 262                 WARN_ON(trans->transid == 0);
 263                 btrfs_set_node_ptr_generation(parent, parent_slot,
 264                                               trans->transid);
 265                 btrfs_mark_buffer_dirty(parent);
 266                 WARN_ON(btrfs_header_generation(parent) != trans->transid);
 267                 btrfs_free_extent(trans, root, buf->start, buf->len,
 268                                   btrfs_header_owner(parent), root_gen,
 269                                   0, 0, 1);
 270         }
 271         if (unlock_orig)
 272                 btrfs_tree_unlock(buf);
 273         free_extent_buffer(buf);
 274         btrfs_mark_buffer_dirty(cow);
 275         *cow_ret = cow;
 276         return 0;
 277 }
 278
 279 int btrfs_cow_block(struct btrfs_trans_handle *trans,
 280                     struct btrfs_root *root, struct extent_buffer *buf,
 281                     struct extent_buffer *parent, int parent_slot,
 282                     struct extent_buffer **cow_ret)
 283 {
 284         u64 search_start;
 285         u64 header_trans;
 286         int ret;
 287
 288         if (trans->transaction != root->fs_info->running_transaction) {
 289                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 290                        root->fs_info->running_transaction->transid);
 291                 WARN_ON(1);
 292         }
 293         if (trans->transid != root->fs_info->generation) {
 294                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 295                        root->fs_info->generation);
 296                 WARN_ON(1);
 297         }
 298
 299         header_trans = btrfs_header_generation(buf);
 300         spin_lock(&root->fs_info->hash_lock);
 301         if (header_trans == trans->transid &&
 302             !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
 303                 *cow_ret = buf;
 304                 spin_unlock(&root->fs_info->hash_lock);
 305                 return 0;
 306         }
 307         spin_unlock(&root->fs_info->hash_lock);
 308         search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
 309         ret = __btrfs_cow_block(trans, root, buf, parent,
 310                                  parent_slot, cow_ret, search_start, 0);
 311         return ret;
 312 }
 313
 314 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
 315 {
 316         if (blocknr < other && other - (blocknr + blocksize) < 32768)
 317                 return 1;
 318         if (blocknr > other && blocknr - (other + blocksize) < 32768)
 319                 return 1;
 320         return 0;
 321 }
 322
 323 /*
 324  * compare two keys in a memcmp fashion
 325  */
 326 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
 327 {
 328         struct btrfs_key k1;
 329
 330         btrfs_disk_key_to_cpu(&k1, disk);
 331
 332         if (k1.objectid > k2->objectid)
 333                 return 1;
 334         if (k1.objectid < k2->objectid)
 335                 return -1;
 336         if (k1.type > k2->type)
 337                 return 1;
 338         if (k1.type < k2->type)
 339                 return -1;
 340         if (k1.offset > k2->offset)
 341                 return 1;
 342         if (k1.offset < k2->offset)
 343                 return -1;
 344         return 0;
 345 }
 346
 347
 348 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 349                        struct btrfs_root *root, struct extent_buffer *parent,
 350                        int start_slot, int cache_only, u64 *last_ret,
 351                        struct btrfs_key *progress)
 352 {
 353         struct extent_buffer *cur;
 354         u64 blocknr;
 355         u64 gen;
 356         u64 search_start = *last_ret;
 357         u64 last_block = 0;
 358         u64 other;
 359         u32 parent_nritems;
 360         int end_slot;
 361         int i;
 362         int err = 0;
 363         int parent_level;
 364         int uptodate;
 365         u32 blocksize;
 366         int progress_passed = 0;
 367         struct btrfs_disk_key disk_key;
 368
 369         parent_level = btrfs_header_level(parent);
 370         if (cache_only && parent_level != 1)
 371                 return 0;
 372
 373         if (trans->transaction != root->fs_info->running_transaction) {
 374                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 375                        root->fs_info->running_transaction->transid);
 376                 WARN_ON(1);
 377         }
 378         if (trans->transid != root->fs_info->generation) {
 379                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 380                        root->fs_info->generation);
 381                 WARN_ON(1);
 382         }
 383
 384         parent_nritems = btrfs_header_nritems(parent);
 385         blocksize = btrfs_level_size(root, parent_level - 1);
 386         end_slot = parent_nritems;
 387
 388         if (parent_nritems == 1)
 389                 return 0;
 390
 391         for (i = start_slot; i < end_slot; i++) {
 392                 int close = 1;
 393
 394                 if (!parent->map_token) {
 395                         map_extent_buffer(parent,
 396                                         btrfs_node_key_ptr_offset(i),
 397                                         sizeof(struct btrfs_key_ptr),
 398                                         &parent->map_token, &parent->kaddr,
 399                                         &parent->map_start, &parent->map_len,
 400                                         KM_USER1);
 401                 }
 402                 btrfs_node_key(parent, &disk_key, i);
 403                 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
 404                         continue;
 405
 406                 progress_passed = 1;
 407                 blocknr = btrfs_node_blockptr(parent, i);
 408                 gen = btrfs_node_ptr_generation(parent, i);
 409                 if (last_block == 0)
 410                         last_block = blocknr;
 411
 412                 if (i > 0) {
 413                         other = btrfs_node_blockptr(parent, i - 1);
 414                         close = close_blocks(blocknr, other, blocksize);
 415                 }
 416                 if (!close && i < end_slot - 2) {
 417                         other = btrfs_node_blockptr(parent, i + 1);
 418                         close = close_blocks(blocknr, other, blocksize);
 419                 }
 420                 if (close) {
 421                         last_block = blocknr;
 422                         continue;
 423                 }
 424                 if (parent->map_token) {
 425                         unmap_extent_buffer(parent, parent->map_token,
 426                                             KM_USER1);
 427                         parent->map_token = NULL;
 428                 }
 429
 430                 cur = btrfs_find_tree_block(root, blocknr, blocksize);
 431                 if (cur)
 432                         uptodate = btrfs_buffer_uptodate(cur, gen);
 433                 else
 434                         uptodate = 0;
 435                 if (!cur || !uptodate) {
 436                         if (cache_only) {
 437                                 free_extent_buffer(cur);
 438                                 continue;
 439                         }
 440                         if (!cur) {
 441                                 cur = read_tree_block(root, blocknr,
 442                                                          blocksize, gen);
 443                         } else if (!uptodate) {
 444                                 btrfs_read_buffer(cur, gen);
 445                         }
 446                 }
 447                 if (search_start == 0)
 448                         search_start = last_block;
 449
 450                 btrfs_tree_lock(cur);
 451                 err = __btrfs_cow_block(trans, root, cur, parent, i,
 452                                         &cur, search_start,
 453                                         min(16 * blocksize,
 454                                             (end_slot - i) * blocksize));
 455                 if (err) {
 456                         btrfs_tree_unlock(cur);
 457                         free_extent_buffer(cur);
 458                         break;
 459                 }
 460                 search_start = cur->start;
 461                 last_block = cur->start;
 462                 *last_ret = search_start;
 463                 btrfs_tree_unlock(cur);
 464                 free_extent_buffer(cur);
 465         }
 466         if (parent->map_token) {
 467                 unmap_extent_buffer(parent, parent->map_token,
 468                                     KM_USER1);
 469                 parent->map_token = NULL;
 470         }
 471         return err;
 472 }
 473
 474 /*
 475  * The leaf data grows from end-to-front in the node.
 476  * this returns the address of the start of the last item,
 477  * which is the stop of the leaf data stack
 478  */
 479 static inline unsigned int leaf_data_end(struct btrfs_root *root,
 480                                          struct extent_buffer *leaf)
 481 {
 482         u32 nr = btrfs_header_nritems(leaf);
 483         if (nr == 0)
 484                 return BTRFS_LEAF_DATA_SIZE(root);
 485         return btrfs_item_offset_nr(leaf, nr - 1);
 486 }
 487
 488 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
 489                       int level)
 490 {
 491         struct extent_buffer *parent = NULL;
 492         struct extent_buffer *node = path->nodes[level];
 493         struct btrfs_disk_key parent_key;
 494         struct btrfs_disk_key node_key;
 495         int parent_slot;
 496         int slot;
 497         struct btrfs_key cpukey;
 498         u32 nritems = btrfs_header_nritems(node);
 499
 500         if (path->nodes[level + 1])
 501                 parent = path->nodes[level + 1];
 502
 503         slot = path->slots[level];
 504         BUG_ON(nritems == 0);
 505         if (parent) {
 506                 parent_slot = path->slots[level + 1];
 507                 btrfs_node_key(parent, &parent_key, parent_slot);
 508                 btrfs_node_key(node, &node_key, 0);
 509                 BUG_ON(memcmp(&parent_key, &node_key,
 510                               sizeof(struct btrfs_disk_key)));
 511                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 512                        btrfs_header_bytenr(node));
 513         }
 514         BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
 515         if (slot != 0) {
 516                 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
 517                 btrfs_node_key(node, &node_key, slot);
 518                 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
 519         }
 520         if (slot < nritems - 1) {
 521                 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
 522                 btrfs_node_key(node, &node_key, slot);
 523                 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
 524         }
 525         return 0;
 526 }
 527
 528 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
 529                       int level)
 530 {
 531         struct extent_buffer *leaf = path->nodes[level];
 532         struct extent_buffer *parent = NULL;
 533         int parent_slot;
 534         struct btrfs_key cpukey;
 535         struct btrfs_disk_key parent_key;
 536         struct btrfs_disk_key leaf_key;
 537         int slot = path->slots[0];
 538
 539         u32 nritems = btrfs_header_nritems(leaf);
 540
 541         if (path->nodes[level + 1])
 542                 parent = path->nodes[level + 1];
 543
 544         if (nritems == 0)
 545                 return 0;
 546
 547         if (parent) {
 548                 parent_slot = path->slots[level + 1];
 549                 btrfs_node_key(parent, &parent_key, parent_slot);
 550                 btrfs_item_key(leaf, &leaf_key, 0);
 551
 552                 BUG_ON(memcmp(&parent_key, &leaf_key,
 553                        sizeof(struct btrfs_disk_key)));
 554                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 555                        btrfs_header_bytenr(leaf));
 556         }
 557 #if 0
 558         for (i = 0; nritems > 1 && i < nritems - 2; i++) {
 559                 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
 560                 btrfs_item_key(leaf, &leaf_key, i);
 561                 if (comp_keys(&leaf_key, &cpukey) >= 0) {
 562                         btrfs_print_leaf(root, leaf);
 563                         printk("slot %d offset bad key\n", i);
 564                         BUG_ON(1);
 565                 }
 566                 if (btrfs_item_offset_nr(leaf, i) !=
 567                         btrfs_item_end_nr(leaf, i + 1)) {
 568                         btrfs_print_leaf(root, leaf);
 569                         printk("slot %d offset bad\n", i);
 570                         BUG_ON(1);
 571                 }
 572                 if (i == 0) {
 573                         if (btrfs_item_offset_nr(leaf, i) +
 574                                btrfs_item_size_nr(leaf, i) !=
 575                                BTRFS_LEAF_DATA_SIZE(root)) {
 576                                 btrfs_print_leaf(root, leaf);
 577                                 printk("slot %d first offset bad\n", i);
 578                                 BUG_ON(1);
 579                         }
 580                 }
 581         }
 582         if (nritems > 0) {
 583                 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
 584                                 btrfs_print_leaf(root, leaf);
 585                                 printk("slot %d bad size \n", nritems - 1);
 586                                 BUG_ON(1);
 587                 }
 588         }
 589 #endif
 590         if (slot != 0 && slot < nritems - 1) {
 591                 btrfs_item_key(leaf, &leaf_key, slot);
 592                 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
 593                 if (comp_keys(&leaf_key, &cpukey) <= 0) {
 594                         btrfs_print_leaf(root, leaf);
 595                         printk("slot %d offset bad key\n", slot);
 596                         BUG_ON(1);
 597                 }
 598                 if (btrfs_item_offset_nr(leaf, slot - 1) !=
 599                        btrfs_item_end_nr(leaf, slot)) {
 600                         btrfs_print_leaf(root, leaf);
 601                         printk("slot %d offset bad\n", slot);
 602                         BUG_ON(1);
 603                 }
 604         }
 605         if (slot < nritems - 1) {
 606                 btrfs_item_key(leaf, &leaf_key, slot);
 607                 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
 608                 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
 609                 if (btrfs_item_offset_nr(leaf, slot) !=
 610                         btrfs_item_end_nr(leaf, slot + 1)) {
 611                         btrfs_print_leaf(root, leaf);
 612                         printk("slot %d offset bad\n", slot);
 613                         BUG_ON(1);
 614                 }
 615         }
 616         BUG_ON(btrfs_item_offset_nr(leaf, 0) +
 617                btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
 618         return 0;
 619 }
 620
 621 static int noinline check_block(struct btrfs_root *root,
 622                                 struct btrfs_path *path, int level)
 623 {
 624         u64 found_start;
 625         return 0;
 626         if (btrfs_header_level(path->nodes[level]) != level)
 627             printk("warning: bad level %Lu wanted %d found %d\n",
 628                    path->nodes[level]->start, level,
 629                    btrfs_header_level(path->nodes[level]));
 630         found_start = btrfs_header_bytenr(path->nodes[level]);
 631         if (found_start != path->nodes[level]->start) {
 632             printk("warning: bad bytentr %Lu found %Lu\n",
 633                    path->nodes[level]->start, found_start);
 634         }
 635 #if 0
 636         struct extent_buffer *buf = path->nodes[level];
 637
 638         if (memcmp_extent_buffer(buf, root->fs_info->fsid,
 639                                  (unsigned long)btrfs_header_fsid(buf),
 640                                  BTRFS_FSID_SIZE)) {
 641                 printk("warning bad block %Lu\n", buf->start);
 642                 return 1;
 643         }
 644 #endif
 645         if (level == 0)
 646                 return check_leaf(root, path, level);
 647         return check_node(root, path, level);
 648 }
 649
 650 /*
 651  * search for key in the extent_buffer.  The items start at offset p,
 652  * and they are item_size apart.  There are 'max' items in p.
 653  *
 654  * the slot in the array is returned via slot, and it points to
 655  * the place where you would insert key if it is not found in
 656  * the array.
 657  *
 658  * slot may point to max if the key is bigger than all of the keys
 659  */
 660 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
 661                               int item_size, struct btrfs_key *key,
 662                               int max, int *slot)
 663 {
 664         int low = 0;
 665         int high = max;
 666         int mid;
 667         int ret;
 668         struct btrfs_disk_key *tmp = NULL;
 669         struct btrfs_disk_key unaligned;
 670         unsigned long offset;
 671         char *map_token = NULL;
 672         char *kaddr = NULL;
 673         unsigned long map_start = 0;
 674         unsigned long map_len = 0;
 675         int err;
 676
 677         while(low < high) {
 678                 mid = (low + high) / 2;
 679                 offset = p + mid * item_size;
 680
 681                 if (!map_token || offset < map_start ||
 682                     (offset + sizeof(struct btrfs_disk_key)) >
 683                     map_start + map_len) {
 684                         if (map_token) {
 685                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 686                                 map_token = NULL;
 687                         }
 688                         err = map_extent_buffer(eb, offset,
 689                                                 sizeof(struct btrfs_disk_key),
 690                                                 &map_token, &kaddr,
 691                                                 &map_start, &map_len, KM_USER0);
 692
 693                         if (!err) {
 694                                 tmp = (struct btrfs_disk_key *)(kaddr + offset -
 695                                                         map_start);
 696                         } else {
 697                                 read_extent_buffer(eb, &unaligned,
 698                                                    offset, sizeof(unaligned));
 699                                 tmp = &unaligned;
 700                         }
 701
 702                 } else {
 703                         tmp = (struct btrfs_disk_key *)(kaddr + offset -
 704                                                         map_start);
 705                 }
 706                 ret = comp_keys(tmp, key);
 707
 708                 if (ret < 0)
 709                         low = mid + 1;
 710                 else if (ret > 0)
 711                         high = mid;
 712                 else {
 713                         *slot = mid;
 714                         if (map_token)
 715                                 unmap_extent_buffer(eb, map_token, KM_USER0);
 716                         return 0;
 717                 }
 718         }
 719         *slot = low;
 720         if (map_token)
 721                 unmap_extent_buffer(eb, map_token, KM_USER0);
 722         return 1;
 723 }
 724
 725 /*
 726  * simple bin_search frontend that does the right thing for
 727  * leaves vs nodes
 728  */
 729 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
 730                       int level, int *slot)
 731 {
 732         if (level == 0) {
 733                 return generic_bin_search(eb,
 734                                           offsetof(struct btrfs_leaf, items),
 735                                           sizeof(struct btrfs_item),
 736                                           key, btrfs_header_nritems(eb),
 737                                           slot);
 738         } else {
 739                 return generic_bin_search(eb,
 740                                           offsetof(struct btrfs_node, ptrs),
 741                                           sizeof(struct btrfs_key_ptr),
 742                                           key, btrfs_header_nritems(eb),
 743                                           slot);
 744         }
 745         return -1;
 746 }
 747
 748 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
 749                                    struct extent_buffer *parent, int slot)
 750 {
 751         int level = btrfs_header_level(parent);
 752         if (slot < 0)
 753                 return NULL;
 754         if (slot >= btrfs_header_nritems(parent))
 755                 return NULL;
 756
 757         BUG_ON(level == 0);
 758
 759         return read_tree_block(root, btrfs_node_blockptr(parent, slot),
 760                        btrfs_level_size(root, level - 1),
 761                        btrfs_node_ptr_generation(parent, slot));
 762 }
 763
 764 static int balance_level(struct btrfs_trans_handle *trans,
 765                          struct btrfs_root *root,
 766                          struct btrfs_path *path, int level)
 767 {
 768         struct extent_buffer *right = NULL;
 769         struct extent_buffer *mid;
 770         struct extent_buffer *left = NULL;
 771         struct extent_buffer *parent = NULL;
 772         int ret = 0;
 773         int wret;
 774         int pslot;
 775         int orig_slot = path->slots[level];
 776         int err_on_enospc = 0;
 777         u64 orig_ptr;
 778
 779         if (level == 0)
 780                 return 0;
 781
 782         mid = path->nodes[level];
 783         WARN_ON(!path->locks[level]);
 784         WARN_ON(btrfs_header_generation(mid) != trans->transid);
 785
 786         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 787
 788         if (level < BTRFS_MAX_LEVEL - 1)
 789                 parent = path->nodes[level + 1];
 790         pslot = path->slots[level + 1];
 791
 792         /*
 793          * deal with the case where there is only one pointer in the root
 794          * by promoting the node below to a root
 795          */
 796         if (!parent) {
 797                 struct extent_buffer *child;
 798
 799                 if (btrfs_header_nritems(mid) != 1)
 800                         return 0;
 801
 802                 /* promote the child to a root */
 803                 child = read_node_slot(root, mid, 0);
 804                 btrfs_tree_lock(child);
 805                 BUG_ON(!child);
 806                 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
 807                 BUG_ON(ret);
 808
 809                 spin_lock(&root->node_lock);
 810                 root->node = child;
 811                 spin_unlock(&root->node_lock);
 812
 813                 add_root_to_dirty_list(root);
 814                 btrfs_tree_unlock(child);
 815                 path->locks[level] = 0;
 816                 path->nodes[level] = NULL;
 817                 clean_tree_block(trans, root, mid);
 818                 btrfs_tree_unlock(mid);
 819                 /* once for the path */
 820                 free_extent_buffer(mid);
 821                 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
 822                                         root->root_key.objectid,
 823                                         btrfs_header_generation(mid), 0, 0, 1);
 824                 /* once for the root ptr */
 825                 free_extent_buffer(mid);
 826                 return ret;
 827         }
 828         if (btrfs_header_nritems(mid) >
 829             BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
 830                 return 0;
 831
 832         if (btrfs_header_nritems(mid) < 2)
 833                 err_on_enospc = 1;
 834
 835         left = read_node_slot(root, parent, pslot - 1);
 836         if (left) {
 837                 btrfs_tree_lock(left);
 838                 wret = btrfs_cow_block(trans, root, left,
 839                                        parent, pslot - 1, &left);
 840                 if (wret) {
 841                         ret = wret;
 842                         goto enospc;
 843                 }
 844         }
 845         right = read_node_slot(root, parent, pslot + 1);
 846         if (right) {
 847                 btrfs_tree_lock(right);
 848                 wret = btrfs_cow_block(trans, root, right,
 849                                        parent, pslot + 1, &right);
 850                 if (wret) {
 851                         ret = wret;
 852                         goto enospc;
 853                 }
 854         }
 855
 856         /* first, try to make some room in the middle buffer */
 857         if (left) {
 858                 orig_slot += btrfs_header_nritems(left);
 859                 wret = push_node_left(trans, root, left, mid, 1);
 860                 if (wret < 0)
 861                         ret = wret;
 862                 if (btrfs_header_nritems(mid) < 2)
 863                         err_on_enospc = 1;
 864         }
 865
 866         /*
 867          * then try to empty the right most buffer into the middle
 868          */
 869         if (right) {
 870                 wret = push_node_left(trans, root, mid, right, 1);
 871                 if (wret < 0 && wret != -ENOSPC)
 872                         ret = wret;
 873                 if (btrfs_header_nritems(right) == 0) {
 874                         u64 bytenr = right->start;
 875                         u64 generation = btrfs_header_generation(parent);
 876                         u32 blocksize = right->len;
 877
 878                         clean_tree_block(trans, root, right);
 879                         btrfs_tree_unlock(right);
 880                         free_extent_buffer(right);
 881                         right = NULL;
 882                         wret = del_ptr(trans, root, path, level + 1, pslot +
 883                                        1);
 884                         if (wret)
 885                                 ret = wret;
 886                         wret = btrfs_free_extent(trans, root, bytenr,
 887                                                  blocksize,
 888                                                  btrfs_header_owner(parent),
 889                                                  generation, 0, 0, 1);
 890                         if (wret)
 891                                 ret = wret;
 892                 } else {
 893                         struct btrfs_disk_key right_key;
 894                         btrfs_node_key(right, &right_key, 0);
 895                         btrfs_set_node_key(parent, &right_key, pslot + 1);
 896                         btrfs_mark_buffer_dirty(parent);
 897                 }
 898         }
 899         if (btrfs_header_nritems(mid) == 1) {
 900                 /*
 901                  * we're not allowed to leave a node with one item in the
 902                  * tree during a delete.  A deletion from lower in the tree
 903                  * could try to delete the only pointer in this node.
 904                  * So, pull some keys from the left.
 905                  * There has to be a left pointer at this point because
 906                  * otherwise we would have pulled some pointers from the
 907                  * right
 908                  */
 909                 BUG_ON(!left);
 910                 wret = balance_node_right(trans, root, mid, left);
 911                 if (wret < 0) {
 912                         ret = wret;
 913                         goto enospc;
 914                 }
 915                 if (wret == 1) {
 916                         wret = push_node_left(trans, root, left, mid, 1);
 917                         if (wret < 0)
 918                                 ret = wret;
 919                 }
 920                 BUG_ON(wret == 1);
 921         }
 922         if (btrfs_header_nritems(mid) == 0) {
 923                 /* we've managed to empty the middle node, drop it */
 924                 u64 root_gen = btrfs_header_generation(parent);
 925                 u64 bytenr = mid->start;
 926                 u32 blocksize = mid->len;
 927
 928                 clean_tree_block(trans, root, mid);
 929                 btrfs_tree_unlock(mid);
 930                 free_extent_buffer(mid);
 931                 mid = NULL;
 932                 wret = del_ptr(trans, root, path, level + 1, pslot);
 933                 if (wret)
 934                         ret = wret;
 935                 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
 936                                          btrfs_header_owner(parent),
 937                                          root_gen, 0, 0, 1);
 938                 if (wret)
 939                         ret = wret;
 940         } else {
 941                 /* update the parent key to reflect our changes */
 942                 struct btrfs_disk_key mid_key;
 943                 btrfs_node_key(mid, &mid_key, 0);
 944                 btrfs_set_node_key(parent, &mid_key, pslot);
 945                 btrfs_mark_buffer_dirty(parent);
 946         }
 947
 948         /* update the path */
 949         if (left) {
 950                 if (btrfs_header_nritems(left) > orig_slot) {
 951                         extent_buffer_get(left);
 952                         /* left was locked after cow */
 953                         path->nodes[level] = left;
 954                         path->slots[level + 1] -= 1;
 955                         path->slots[level] = orig_slot;
 956                         if (mid) {
 957                                 btrfs_tree_unlock(mid);
 958                                 free_extent_buffer(mid);
 959                         }
 960                 } else {
 961                         orig_slot -= btrfs_header_nritems(left);
 962                         path->slots[level] = orig_slot;
 963                 }
 964         }
 965         /* double check we haven't messed things up */
 966         check_block(root, path, level);
 967         if (orig_ptr !=
 968             btrfs_node_blockptr(path->nodes[level], path->slots[level]))
 969                 BUG();
 970 enospc:
 971         if (right) {
 972                 btrfs_tree_unlock(right);
 973                 free_extent_buffer(right);
 974         }
 975         if (left) {
 976                 if (path->nodes[level] != left)
 977                         btrfs_tree_unlock(left);
 978                 free_extent_buffer(left);
 979         }
 980         return ret;
 981 }
 982
 983 /* returns zero if the push worked, non-zero otherwise */
 984 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
 985                                           struct btrfs_root *root,
 986                                           struct btrfs_path *path, int level)
 987 {
 988         struct extent_buffer *right = NULL;
 989         struct extent_buffer *mid;
 990         struct extent_buffer *left = NULL;
 991         struct extent_buffer *parent = NULL;
 992         int ret = 0;
 993         int wret;
 994         int pslot;
 995         int orig_slot = path->slots[level];
 996         u64 orig_ptr;
 997
 998         if (level == 0)
 999                 return 1;
1000
1001         mid = path->nodes[level];
1002         WARN_ON(btrfs_header_generation(mid) != trans->transid);
1003         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
1004
1005         if (level < BTRFS_MAX_LEVEL - 1)
1006                 parent = path->nodes[level + 1];
1007         pslot = path->slots[level + 1];
1008
1009         if (!parent)
1010                 return 1;
1011
1012         left = read_node_slot(root, parent, pslot - 1);
1013
1014         /* first, try to make some room in the middle buffer */
1015         if (left) {
1016                 u32 left_nr;
1017
1018                 btrfs_tree_lock(left);
1019                 left_nr = btrfs_header_nritems(left);
1020                 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1021                         wret = 1;
1022                 } else {
1023                         ret = btrfs_cow_block(trans, root, left, parent,
1024                                               pslot - 1, &left);
1025                         if (ret)
1026                                 wret = 1;
1027                         else {
1028                                 wret = push_node_left(trans, root,
1029                                                       left, mid, 0);
1030                         }
1031                 }
1032                 if (wret < 0)
1033                         ret = wret;
1034                 if (wret == 0) {
1035                         struct btrfs_disk_key disk_key;
1036                         orig_slot += left_nr;
1037                         btrfs_node_key(mid, &disk_key, 0);
1038                         btrfs_set_node_key(parent, &disk_key, pslot);
1039                         btrfs_mark_buffer_dirty(parent);
1040                         if (btrfs_header_nritems(left) > orig_slot) {
1041                                 path->nodes[level] = left;
1042                                 path->slots[level + 1] -= 1;
1043                                 path->slots[level] = orig_slot;
1044                                 btrfs_tree_unlock(mid);
1045                                 free_extent_buffer(mid);
1046                         } else {
1047                                 orig_slot -=
1048                                         btrfs_header_nritems(left);
1049                                 path->slots[level] = orig_slot;
1050                                 btrfs_tree_unlock(left);
1051                                 free_extent_buffer(left);
1052                         }
1053                         return 0;
1054                 }
1055                 btrfs_tree_unlock(left);
1056                 free_extent_buffer(left);
1057         }
1058         right = read_node_slot(root, parent, pslot + 1);
1059
1060         /*
1061          * then try to empty the right most buffer into the middle
1062          */
1063         if (right) {
1064                 u32 right_nr;
1065                 btrfs_tree_lock(right);
1066                 right_nr = btrfs_header_nritems(right);
1067                 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1068                         wret = 1;
1069                 } else {
1070                         ret = btrfs_cow_block(trans, root, right,
1071                                               parent, pslot + 1,
1072                                               &right);
1073                         if (ret)
1074                                 wret = 1;
1075                         else {
1076                                 wret = balance_node_right(trans, root,
1077                                                           right, mid);
1078                         }
1079                 }
1080                 if (wret < 0)
1081                         ret = wret;
1082                 if (wret == 0) {
1083                         struct btrfs_disk_key disk_key;
1084
1085                         btrfs_node_key(right, &disk_key, 0);
1086                         btrfs_set_node_key(parent, &disk_key, pslot + 1);
1087                         btrfs_mark_buffer_dirty(parent);
1088
1089                         if (btrfs_header_nritems(mid) <= orig_slot) {
1090                                 path->nodes[level] = right;
1091                                 path->slots[level + 1] += 1;
1092                                 path->slots[level] = orig_slot -
1093                                         btrfs_header_nritems(mid);
1094                                 btrfs_tree_unlock(mid);
1095                                 free_extent_buffer(mid);
1096                         } else {
1097                                 btrfs_tree_unlock(right);
1098                                 free_extent_buffer(right);
1099                         }
1100                         return 0;
1101                 }
1102                 btrfs_tree_unlock(right);
1103                 free_extent_buffer(right);
1104         }
1105         return 1;
1106 }
1107
1108 /*
1109  * readahead one full node of leaves
1110  */
1111 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
1112                              int level, int slot, u64 objectid)
1113 {
1114         struct extent_buffer *node;
1115         struct btrfs_disk_key disk_key;
1116         u32 nritems;
1117         u64 search;
1118         u64 lowest_read;
1119         u64 highest_read;
1120         u64 nread = 0;
1121         int direction = path->reada;
1122         struct extent_buffer *eb;
1123         u32 nr;
1124         u32 blocksize;
1125         u32 nscan = 0;
1126
1127         if (level != 1)
1128                 return;
1129
1130         if (!path->nodes[level])
1131                 return;
1132
1133         node = path->nodes[level];
1134
1135         search = btrfs_node_blockptr(node, slot);
1136         blocksize = btrfs_level_size(root, level - 1);
1137         eb = btrfs_find_tree_block(root, search, blocksize);
1138         if (eb) {
1139                 free_extent_buffer(eb);
1140                 return;
1141         }
1142
1143         highest_read = search;
1144         lowest_read = search;
1145
1146         nritems = btrfs_header_nritems(node);
1147         nr = slot;
1148         while(1) {
1149                 if (direction < 0) {
1150                         if (nr == 0)
1151                                 break;
1152                         nr--;
1153                 } else if (direction > 0) {
1154                         nr++;
1155                         if (nr >= nritems)
1156                                 break;
1157                 }
1158                 if (path->reada < 0 && objectid) {
1159                         btrfs_node_key(node, &disk_key, nr);
1160                         if (btrfs_disk_key_objectid(&disk_key) != objectid)
1161                                 break;
1162                 }
1163                 search = btrfs_node_blockptr(node, nr);
1164                 if ((search >= lowest_read && search <= highest_read) ||
1165                     (search < lowest_read && lowest_read - search <= 32768) ||
1166                     (search > highest_read && search - highest_read <= 32768)) {
1167                         readahead_tree_block(root, search, blocksize,
1168                                      btrfs_node_ptr_generation(node, nr));
1169                         nread += blocksize;
1170                 }
1171                 nscan++;
1172                 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1173                         break;
1174                 if(nread > (1024 * 1024) || nscan > 128)
1175                         break;
1176
1177                 if (search < lowest_read)
1178                         lowest_read = search;
1179                 if (search > highest_read)
1180                         highest_read = search;
1181         }
1182 }
1183
1184 static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
1185 {
1186         int i;
1187         int skip_level = level;
1188         int no_skips = 0;
1189         struct extent_buffer *t;
1190
1191         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1192                 if (!path->nodes[i])
1193                         break;
1194                 if (!path->locks[i])
1195                         break;
1196                 if (!no_skips && path->slots[i] == 0) {
1197                         skip_level = i + 1;
1198                         continue;
1199                 }
1200                 if (!no_skips && path->keep_locks) {
1201                         u32 nritems;
1202                         t = path->nodes[i];
1203                         nritems = btrfs_header_nritems(t);
1204                         if (nritems < 1 || path->slots[i] >= nritems - 1) {
1205                                 skip_level = i + 1;
1206                                 continue;
1207                         }
1208                 }
1209                 if (skip_level < i && i >= lowest_unlock)
1210                         no_skips = 1;
1211
1212                 t = path->nodes[i];
1213                 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
1214                         btrfs_tree_unlock(t);
1215                         path->locks[i] = 0;
1216                 }
1217         }
1218 }
1219
1220 /*
1221  * look for key in the tree.  path is filled in with nodes along the way
1222  * if key is found, we return zero and you can find the item in the leaf
1223  * level of the path (level 0)
1224  *
1225  * If the key isn't found, the path points to the slot where it should
1226  * be inserted, and 1 is returned.  If there are other errors during the
1227  * search a negative error number is returned.
1228  *
1229  * if ins_len > 0, nodes and leaves will be split as we walk down the
1230  * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
1231  * possible)
1232  */
1233 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1234                       *root, struct btrfs_key *key, struct btrfs_path *p, int
1235                       ins_len, int cow)
1236 {
1237         struct extent_buffer *b;
1238         struct extent_buffer *tmp;
1239         int slot;
1240         int ret;
1241         int level;
1242         int should_reada = p->reada;
1243         int lowest_unlock = 1;
1244         int blocksize;
1245         u8 lowest_level = 0;
1246         u64 blocknr;
1247         u64 gen;
1248
1249         lowest_level = p->lowest_level;
1250         WARN_ON(lowest_level && ins_len);
1251         WARN_ON(p->nodes[0] != NULL);
1252         WARN_ON(cow && root == root->fs_info->extent_root &&
1253                 !mutex_is_locked(&root->fs_info->alloc_mutex));
1254         if (ins_len < 0)
1255                 lowest_unlock = 2;
1256 again:
1257         if (p->skip_locking)
1258                 b = btrfs_root_node(root);
1259         else
1260                 b = btrfs_lock_root_node(root);
1261
1262         while (b) {
1263                 level = btrfs_header_level(b);
1264                 if (cow) {
1265                         int wret;
1266                         wret = btrfs_cow_block(trans, root, b,
1267                                                p->nodes[level + 1],
1268                                                p->slots[level + 1],
1269                                                &b);
1270                         if (wret) {
1271                                 free_extent_buffer(b);
1272                                 return wret;
1273                         }
1274                 }
1275                 BUG_ON(!cow && ins_len);
1276                 if (level != btrfs_header_level(b))
1277                         WARN_ON(1);
1278                 level = btrfs_header_level(b);
1279                 p->nodes[level] = b;
1280                 if (!p->skip_locking)
1281                         p->locks[level] = 1;
1282                 ret = check_block(root, p, level);
1283                 if (ret)
1284                         return -1;
1285
1286                 ret = bin_search(b, key, level, &slot);
1287                 if (level != 0) {
1288                         if (ret && slot > 0)
1289                                 slot -= 1;
1290                         p->slots[level] = slot;
1291                         if (ins_len > 0 && btrfs_header_nritems(b) >=
1292                             BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1293                                 int sret = split_node(trans, root, p, level);
1294                                 BUG_ON(sret > 0);
1295                                 if (sret)
1296                                         return sret;
1297                                 b = p->nodes[level];
1298                                 slot = p->slots[level];
1299                         } else if (ins_len < 0) {
1300                                 int sret = balance_level(trans, root, p,
1301                                                          level);
1302                                 if (sret)
1303                                         return sret;
1304                                 b = p->nodes[level];
1305                                 if (!b) {
1306                                         btrfs_release_path(NULL, p);
1307                                         goto again;
1308                                 }
1309                                 slot = p->slots[level];
1310                                 BUG_ON(btrfs_header_nritems(b) == 1);
1311                         }
1312                         unlock_up(p, level, lowest_unlock);
1313
1314                         /* this is only true while dropping a snapshot */
1315                         if (level == lowest_level) {
1316                                 break;
1317                         }
1318
1319                         blocknr = btrfs_node_blockptr(b, slot);
1320                         gen = btrfs_node_ptr_generation(b, slot);
1321                         blocksize = btrfs_level_size(root, level - 1);
1322
1323                         tmp = btrfs_find_tree_block(root, blocknr, blocksize);
1324                         if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
1325                                 b = tmp;
1326                         } else {
1327                                 /*
1328                                  * reduce lock contention at high levels
1329                                  * of the btree by dropping locks before
1330                                  * we read.
1331                                  */
1332                                 if (level > 1) {
1333                                         btrfs_release_path(NULL, p);
1334                                         if (tmp)
1335                                                 free_extent_buffer(tmp);
1336                                         if (should_reada)
1337                                                 reada_for_search(root, p,
1338                                                                  level, slot,
1339                                                                  key->objectid);
1340
1341                                         tmp = read_tree_block(root, blocknr,
1342                                                          blocksize, gen);
1343                                         if (tmp)
1344                                                 free_extent_buffer(tmp);
1345                                         goto again;
1346                                 } else {
1347                                         if (tmp)
1348                                                 free_extent_buffer(tmp);
1349                                         if (should_reada)
1350                                                 reada_for_search(root, p,
1351                                                                  level, slot,
1352                                                                  key->objectid);
1353                                         b = read_node_slot(root, b, slot);
1354                                 }
1355                         }
1356                         if (!p->skip_locking)
1357                                 btrfs_tree_lock(b);
1358                 } else {
1359                         p->slots[level] = slot;
1360                         if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1361                             sizeof(struct btrfs_item) + ins_len) {
1362                                 int sret = split_leaf(trans, root, key,
1363                                                       p, ins_len, ret == 0);
1364                                 BUG_ON(sret > 0);
1365                                 if (sret)
1366                                         return sret;
1367                         }
1368                         unlock_up(p, level, lowest_unlock);
1369                         return ret;
1370                 }
1371         }
1372         return 1;
1373 }
1374
1375 /*
1376  * adjust the pointers going up the tree, starting at level
1377  * making sure the right key of each node is points to 'key'.
1378  * This is used after shifting pointers to the left, so it stops
1379  * fixing up pointers when a given leaf/node is not in slot 0 of the
1380  * higher levels
1381  *
1382  * If this fails to write a tree block, it returns -1, but continues
1383  * fixing up the blocks in ram so the tree is consistent.
1384  */
1385 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1386                           struct btrfs_root *root, struct btrfs_path *path,
1387                           struct btrfs_disk_key *key, int level)
1388 {
1389         int i;
1390         int ret = 0;
1391         struct extent_buffer *t;
1392
1393         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1394                 int tslot = path->slots[i];
1395                 if (!path->nodes[i])
1396                         break;
1397                 t = path->nodes[i];
1398                 btrfs_set_node_key(t, key, tslot);
1399                 btrfs_mark_buffer_dirty(path->nodes[i]);
1400                 if (tslot != 0)
1401                         break;
1402         }
1403         return ret;
1404 }
1405
1406 /*
1407  * try to push data from one node into the next node left in the
1408  * tree.
1409  *
1410  * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1411  * error, and > 0 if there was no room in the left hand block.
1412  */
1413 static int push_node_left(struct btrfs_trans_handle *trans,
1414                           struct btrfs_root *root, struct extent_buffer *dst,
1415                           struct extent_buffer *src, int empty)
1416 {
1417         int push_items = 0;
1418         int src_nritems;
1419         int dst_nritems;
1420         int ret = 0;
1421
1422         src_nritems = btrfs_header_nritems(src);
1423         dst_nritems = btrfs_header_nritems(dst);
1424         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1425         WARN_ON(btrfs_header_generation(src) != trans->transid);
1426         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1427
1428         if (!empty && src_nritems <= 8)
1429                 return 1;
1430
1431         if (push_items <= 0) {
1432                 return 1;
1433         }
1434
1435         if (empty) {
1436                 push_items = min(src_nritems, push_items);
1437                 if (push_items < src_nritems) {
1438                         /* leave at least 8 pointers in the node if
1439                          * we aren't going to empty it
1440                          */
1441                         if (src_nritems - push_items < 8) {
1442                                 if (push_items <= 8)
1443                                         return 1;
1444                                 push_items -= 8;
1445                         }
1446                 }
1447         } else
1448                 push_items = min(src_nritems - 8, push_items);
1449
1450         copy_extent_buffer(dst, src,
1451                            btrfs_node_key_ptr_offset(dst_nritems),
1452                            btrfs_node_key_ptr_offset(0),
1453                            push_items * sizeof(struct btrfs_key_ptr));
1454
1455         if (push_items < src_nritems) {
1456                 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1457                                       btrfs_node_key_ptr_offset(push_items),
1458                                       (src_nritems - push_items) *
1459                                       sizeof(struct btrfs_key_ptr));
1460         }
1461         btrfs_set_header_nritems(src, src_nritems - push_items);
1462         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1463         btrfs_mark_buffer_dirty(src);
1464         btrfs_mark_buffer_dirty(dst);
1465         return ret;
1466 }
1467
1468 /*
1469  * try to push data from one node into the next node right in the
1470  * tree.
1471  *
1472  * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1473  * error, and > 0 if there was no room in the right hand block.
1474  *
1475  * this will  only push up to 1/2 the contents of the left node over
1476  */
1477 static int balance_node_right(struct btrfs_trans_handle *trans,
1478                               struct btrfs_root *root,
1479                               struct extent_buffer *dst,
1480                               struct extent_buffer *src)
1481 {
1482         int push_items = 0;
1483         int max_push;
1484         int src_nritems;
1485         int dst_nritems;
1486         int ret = 0;
1487
1488         WARN_ON(btrfs_header_generation(src) != trans->transid);
1489         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1490
1491         src_nritems = btrfs_header_nritems(src);
1492         dst_nritems = btrfs_header_nritems(dst);
1493         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1494         if (push_items <= 0) {
1495                 return 1;
1496         }
1497
1498         if (src_nritems < 4) {
1499                 return 1;
1500         }
1501
1502         max_push = src_nritems / 2 + 1;
1503         /* don't try to empty the node */
1504         if (max_push >= src_nritems) {
1505                 return 1;
1506         }
1507
1508         if (max_push < push_items)
1509                 push_items = max_push;
1510
1511         memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1512                                       btrfs_node_key_ptr_offset(0),
1513                                       (dst_nritems) *
1514                                       sizeof(struct btrfs_key_ptr));
1515
1516         copy_extent_buffer(dst, src,
1517                            btrfs_node_key_ptr_offset(0),
1518                            btrfs_node_key_ptr_offset(src_nritems - push_items),
1519                            push_items * sizeof(struct btrfs_key_ptr));
1520
1521         btrfs_set_header_nritems(src, src_nritems - push_items);
1522         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1523
1524         btrfs_mark_buffer_dirty(src);
1525         btrfs_mark_buffer_dirty(dst);
1526         return ret;
1527 }
1528
1529 /*
1530  * helper function to insert a new root level in the tree.
1531  * A new node is allocated, and a single item is inserted to
1532  * point to the existing root
1533  *
1534  * returns zero on success or < 0 on failure.
1535  */
1536 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1537                            struct btrfs_root *root,
1538                            struct btrfs_path *path, int level)
1539 {
1540         u64 root_gen;
1541         u64 lower_gen;
1542         struct extent_buffer *lower;
1543         struct extent_buffer *c;
1544         struct extent_buffer *old;
1545         struct btrfs_disk_key lower_key;
1546
1547         BUG_ON(path->nodes[level]);
1548         BUG_ON(path->nodes[level-1] != root->node);
1549
1550         if (root->ref_cows)
1551                 root_gen = trans->transid;
1552         else
1553                 root_gen = 0;
1554
1555         lower = path->nodes[level-1];
1556         if (level == 1)
1557                 btrfs_item_key(lower, &lower_key, 0);
1558         else
1559                 btrfs_node_key(lower, &lower_key, 0);
1560
1561         c = btrfs_alloc_free_block(trans, root, root->nodesize,
1562                                    root->root_key.objectid,
1563                                    root_gen, lower_key.objectid, level,
1564                                    root->node->start, 0);
1565         if (IS_ERR(c))
1566                 return PTR_ERR(c);
1567
1568         memset_extent_buffer(c, 0, 0, root->nodesize);
1569         btrfs_set_header_nritems(c, 1);
1570         btrfs_set_header_level(c, level);
1571         btrfs_set_header_bytenr(c, c->start);
1572         btrfs_set_header_generation(c, trans->transid);
1573         btrfs_set_header_owner(c, root->root_key.objectid);
1574
1575         write_extent_buffer(c, root->fs_info->fsid,
1576                             (unsigned long)btrfs_header_fsid(c),
1577                             BTRFS_FSID_SIZE);
1578
1579         write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1580                             (unsigned long)btrfs_header_chunk_tree_uuid(c),
1581                             BTRFS_UUID_SIZE);
1582
1583         btrfs_set_node_key(c, &lower_key, 0);
1584         btrfs_set_node_blockptr(c, 0, lower->start);
1585         lower_gen = btrfs_header_generation(lower);
1586         WARN_ON(lower_gen == 0);
1587
1588         btrfs_set_node_ptr_generation(c, 0, lower_gen);
1589
1590         btrfs_mark_buffer_dirty(c);
1591
1592         spin_lock(&root->node_lock);
1593         old = root->node;
1594         root->node = c;
1595         spin_unlock(&root->node_lock);
1596
1597         /* the super has an extra ref to root->node */
1598         free_extent_buffer(old);
1599
1600         add_root_to_dirty_list(root);
1601         extent_buffer_get(c);
1602         path->nodes[level] = c;
1603         path->locks[level] = 1;
1604         path->slots[level] = 0;
1605
1606         if (root->ref_cows && lower_gen != trans->transid) {
1607                 struct btrfs_path *back_path = btrfs_alloc_path();
1608                 int ret;
1609                 mutex_lock(&root->fs_info->alloc_mutex);
1610                 ret = btrfs_insert_extent_backref(trans,
1611                                                   root->fs_info->extent_root,
1612                                                   path, lower->start,
1613                                                   root->root_key.objectid,
1614                                                   trans->transid, 0, 0);
1615                 BUG_ON(ret);
1616                 mutex_unlock(&root->fs_info->alloc_mutex);
1617                 btrfs_free_path(back_path);
1618         }
1619         return 0;
1620 }
1621
1622 /*
1623  * worker function to insert a single pointer in a node.
1624  * the node should have enough room for the pointer already
1625  *
1626  * slot and level indicate where you want the key to go, and
1627  * blocknr is the block the key points to.
1628  *
1629  * returns zero on success and < 0 on any error
1630  */
1631 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1632                       *root, struct btrfs_path *path, struct btrfs_disk_key
1633                       *key, u64 bytenr, int slot, int level)
1634 {
1635         struct extent_buffer *lower;
1636         int nritems;
1637
1638         BUG_ON(!path->nodes[level]);
1639         lower = path->nodes[level];
1640         nritems = btrfs_header_nritems(lower);
1641         if (slot > nritems)
1642                 BUG();
1643         if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1644                 BUG();
1645         if (slot != nritems) {
1646                 memmove_extent_buffer(lower,
1647                               btrfs_node_key_ptr_offset(slot + 1),
1648                               btrfs_node_key_ptr_offset(slot),
1649                               (nritems - slot) * sizeof(struct btrfs_key_ptr));
1650         }
1651         btrfs_set_node_key(lower, key, slot);
1652         btrfs_set_node_blockptr(lower, slot, bytenr);
1653         WARN_ON(trans->transid == 0);
1654         btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1655         btrfs_set_header_nritems(lower, nritems + 1);
1656         btrfs_mark_buffer_dirty(lower);
1657         return 0;
1658 }
1659
1660 /*
1661  * split the node at the specified level in path in two.
1662  * The path is corrected to point to the appropriate node after the split
1663  *
1664  * Before splitting this tries to make some room in the node by pushing
1665  * left and right, if either one works, it returns right away.
1666  *
1667  * returns 0 on success and < 0 on failure
1668  */
1669 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1670                       *root, struct btrfs_path *path, int level)
1671 {
1672         u64 root_gen;
1673         struct extent_buffer *c;
1674         struct extent_buffer *split;
1675         struct btrfs_disk_key disk_key;
1676         int mid;
1677         int ret;
1678         int wret;
1679         u32 c_nritems;
1680
1681         c = path->nodes[level];
1682         WARN_ON(btrfs_header_generation(c) != trans->transid);
1683         if (c == root->node) {
1684                 /* trying to split the root, lets make a new one */
1685                 ret = insert_new_root(trans, root, path, level + 1);
1686                 if (ret)
1687                         return ret;
1688         } else {
1689                 ret = push_nodes_for_insert(trans, root, path, level);
1690                 c = path->nodes[level];
1691                 if (!ret && btrfs_header_nritems(c) <
1692                     BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1693                         return 0;
1694                 if (ret < 0)
1695                         return ret;
1696         }
1697
1698         c_nritems = btrfs_header_nritems(c);
1699         if (root->ref_cows)
1700                 root_gen = trans->transid;
1701         else
1702                 root_gen = 0;
1703
1704         btrfs_node_key(c, &disk_key, 0);
1705         split = btrfs_alloc_free_block(trans, root, root->nodesize,
1706                                          root->root_key.objectid,
1707                                          root_gen,
1708                                          btrfs_disk_key_objectid(&disk_key),
1709                                          level, c->start, 0);
1710         if (IS_ERR(split))
1711                 return PTR_ERR(split);
1712
1713         btrfs_set_header_flags(split, btrfs_header_flags(c));
1714         btrfs_set_header_level(split, btrfs_header_level(c));
1715         btrfs_set_header_bytenr(split, split->start);
1716         btrfs_set_header_generation(split, trans->transid);
1717         btrfs_set_header_owner(split, root->root_key.objectid);
1718         btrfs_set_header_flags(split, 0);
1719         write_extent_buffer(split, root->fs_info->fsid,
1720                             (unsigned long)btrfs_header_fsid(split),
1721                             BTRFS_FSID_SIZE);
1722         write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1723                             (unsigned long)btrfs_header_chunk_tree_uuid(split),
1724                             BTRFS_UUID_SIZE);
1725
1726         mid = (c_nritems + 1) / 2;
1727
1728         copy_extent_buffer(split, c,
1729                            btrfs_node_key_ptr_offset(0),
1730                            btrfs_node_key_ptr_offset(mid),
1731                            (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1732         btrfs_set_header_nritems(split, c_nritems - mid);
1733         btrfs_set_header_nritems(c, mid);
1734         ret = 0;
1735
1736         btrfs_mark_buffer_dirty(c);
1737         btrfs_mark_buffer_dirty(split);
1738
1739         btrfs_node_key(split, &disk_key, 0);
1740         wret = insert_ptr(trans, root, path, &disk_key, split->start,
1741                           path->slots[level + 1] + 1,
1742                           level + 1);
1743         if (wret)
1744                 ret = wret;
1745
1746         if (path->slots[level] >= mid) {
1747                 path->slots[level] -= mid;
1748                 btrfs_tree_unlock(c);
1749                 free_extent_buffer(c);
1750                 path->nodes[level] = split;
1751                 path->slots[level + 1] += 1;
1752         } else {
1753                 btrfs_tree_unlock(split);
1754                 free_extent_buffer(split);
1755         }
1756         return ret;
1757 }
1758
1759 /*
1760  * how many bytes are required to store the items in a leaf.  start
1761  * and nr indicate which items in the leaf to check.  This totals up the
1762  * space used both by the item structs and the item data
1763  */
1764 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1765 {
1766         int data_len;
1767         int nritems = btrfs_header_nritems(l);
1768         int end = min(nritems, start + nr) - 1;
1769
1770         if (!nr)
1771                 return 0;
1772         data_len = btrfs_item_end_nr(l, start);
1773         data_len = data_len - btrfs_item_offset_nr(l, end);
1774         data_len += sizeof(struct btrfs_item) * nr;
1775         WARN_ON(data_len < 0);
1776         return data_len;
1777 }
1778
1779 /*
1780  * The space between the end of the leaf items and
1781  * the start of the leaf data.  IOW, how much room
1782  * the leaf has left for both items and data
1783  */
1784 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1785 {
1786         int nritems = btrfs_header_nritems(leaf);
1787         int ret;
1788         ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1789         if (ret < 0) {
1790                 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1791                        ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1792                        leaf_space_used(leaf, 0, nritems), nritems);
1793         }
1794         return ret;
1795 }
1796
1797 /*
1798  * push some data in the path leaf to the right, trying to free up at
1799  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1800  *
1801  * returns 1 if the push failed because the other node didn't have enough
1802  * room, 0 if everything worked out and < 0 if there were major errors.
1803  */
1804 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1805                            *root, struct btrfs_path *path, int data_size,
1806                            int empty)
1807 {
1808         struct extent_buffer *left = path->nodes[0];
1809         struct extent_buffer *right;
1810         struct extent_buffer *upper;
1811         struct btrfs_disk_key disk_key;
1812         int slot;
1813         u32 i;
1814         int free_space;
1815         int push_space = 0;
1816         int push_items = 0;
1817         struct btrfs_item *item;
1818         u32 left_nritems;
1819         u32 nr;
1820         u32 right_nritems;
1821         u32 data_end;
1822         u32 this_item_size;
1823         int ret;
1824
1825         slot = path->slots[1];
1826         if (!path->nodes[1]) {
1827                 return 1;
1828         }
1829         upper = path->nodes[1];
1830         if (slot >= btrfs_header_nritems(upper) - 1)
1831                 return 1;
1832
1833         WARN_ON(!btrfs_tree_locked(path->nodes[1]));
1834
1835         right = read_node_slot(root, upper, slot + 1);
1836         btrfs_tree_lock(right);
1837         free_space = btrfs_leaf_free_space(root, right);
1838         if (free_space < data_size + sizeof(struct btrfs_item))
1839                 goto out_unlock;
1840
1841         /* cow and double check */
1842         ret = btrfs_cow_block(trans, root, right, upper,
1843                               slot + 1, &right);
1844         if (ret)
1845                 goto out_unlock;
1846
1847         free_space = btrfs_leaf_free_space(root, right);
1848         if (free_space < data_size + sizeof(struct btrfs_item))
1849                 goto out_unlock;
1850
1851         left_nritems = btrfs_header_nritems(left);
1852         if (left_nritems == 0)
1853                 goto out_unlock;
1854
1855         if (empty)
1856                 nr = 0;
1857         else
1858                 nr = 1;
1859
1860         i = left_nritems - 1;
1861         while (i >= nr) {
1862                 item = btrfs_item_nr(left, i);
1863
1864                 if (path->slots[0] == i)
1865                         push_space += data_size + sizeof(*item);
1866
1867                 if (!left->map_token) {
1868                         map_extent_buffer(left, (unsigned long)item,
1869                                         sizeof(struct btrfs_item),
1870                                         &left->map_token, &left->kaddr,
1871                                         &left->map_start, &left->map_len,
1872                                         KM_USER1);
1873                 }
1874
1875                 this_item_size = btrfs_item_size(left, item);
1876                 if (this_item_size + sizeof(*item) + push_space > free_space)
1877                         break;
1878                 push_items++;
1879                 push_space += this_item_size + sizeof(*item);
1880                 if (i == 0)
1881                         break;
1882                 i--;
1883         }
1884         if (left->map_token) {
1885                 unmap_extent_buffer(left, left->map_token, KM_USER1);
1886                 left->map_token = NULL;
1887         }
1888
1889         if (push_items == 0)
1890                 goto out_unlock;
1891
1892         if (!empty && push_items == left_nritems)
1893                 WARN_ON(1);
1894
1895         /* push left to right */
1896         right_nritems = btrfs_header_nritems(right);
1897
1898         push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1899         push_space -= leaf_data_end(root, left);
1900
1901         /* make room in the right data area */
1902         data_end = leaf_data_end(root, right);
1903         memmove_extent_buffer(right,
1904                               btrfs_leaf_data(right) + data_end - push_space,
1905                               btrfs_leaf_data(right) + data_end,
1906                               BTRFS_LEAF_DATA_SIZE(root) - data_end);
1907
1908         /* copy from the left data area */
1909         copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1910                      BTRFS_LEAF_DATA_SIZE(root) - push_space,
1911                      btrfs_leaf_data(left) + leaf_data_end(root, left),
1912                      push_space);
1913
1914         memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1915                               btrfs_item_nr_offset(0),
1916                               right_nritems * sizeof(struct btrfs_item));
1917
1918         /* copy the items from left to right */
1919         copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1920                    btrfs_item_nr_offset(left_nritems - push_items),
1921                    push_items * sizeof(struct btrfs_item));
1922
1923         /* update the item pointers */
1924         right_nritems += push_items;
1925         btrfs_set_header_nritems(right, right_nritems);
1926         push_space = BTRFS_LEAF_DATA_SIZE(root);
1927         for (i = 0; i < right_nritems; i++) {
1928                 item = btrfs_item_nr(right, i);
1929                 if (!right->map_token) {
1930                         map_extent_buffer(right, (unsigned long)item,
1931                                         sizeof(struct btrfs_item),
1932                                         &right->map_token, &right->kaddr,
1933                                         &right->map_start, &right->map_len,
1934                                         KM_USER1);
1935                 }
1936                 push_space -= btrfs_item_size(right, item);
1937                 btrfs_set_item_offset(right, item, push_space);
1938         }
1939
1940         if (right->map_token) {
1941                 unmap_extent_buffer(right, right->map_token, KM_USER1);
1942                 right->map_token = NULL;
1943         }
1944         left_nritems -= push_items;
1945         btrfs_set_header_nritems(left, left_nritems);
1946
1947         if (left_nritems)
1948                 btrfs_mark_buffer_dirty(left);
1949         btrfs_mark_buffer_dirty(right);
1950
1951         btrfs_item_key(right, &disk_key, 0);
1952         btrfs_set_node_key(upper, &disk_key, slot + 1);
1953         btrfs_mark_buffer_dirty(upper);
1954
1955         /* then fixup the leaf pointer in the path */
1956         if (path->slots[0] >= left_nritems) {
1957                 path->slots[0] -= left_nritems;
1958                 if (btrfs_header_nritems(path->nodes[0]) == 0)
1959                         clean_tree_block(trans, root, path->nodes[0]);
1960                 btrfs_tree_unlock(path->nodes[0]);
1961                 free_extent_buffer(path->nodes[0]);
1962                 path->nodes[0] = right;
1963                 path->slots[1] += 1;
1964         } else {
1965                 btrfs_tree_unlock(right);
1966                 free_extent_buffer(right);
1967         }
1968         return 0;
1969
1970 out_unlock:
1971         btrfs_tree_unlock(right);
1972         free_extent_buffer(right);
1973         return 1;
1974 }
1975
1976 /*
1977  * push some data in the path leaf to the left, trying to free up at
1978  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1979  */
1980 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1981                           *root, struct btrfs_path *path, int data_size,
1982                           int empty)
1983 {
1984         struct btrfs_disk_key disk_key;
1985         struct extent_buffer *right = path->nodes[0];
1986         struct extent_buffer *left;
1987         int slot;
1988         int i;
1989         int free_space;
1990         int push_space = 0;
1991         int push_items = 0;
1992         struct btrfs_item *item;
1993         u32 old_left_nritems;
1994         u32 right_nritems;
1995         u32 nr;
1996         int ret = 0;
1997         int wret;
1998         u32 this_item_size;
1999         u32 old_left_item_size;
2000
2001         slot = path->slots[1];
2002         if (slot == 0)
2003                 return 1;
2004         if (!path->nodes[1])
2005                 return 1;
2006
2007         right_nritems = btrfs_header_nritems(right);
2008         if (right_nritems == 0) {
2009                 return 1;
2010         }
2011
2012         WARN_ON(!btrfs_tree_locked(path->nodes[1]));
2013
2014         left = read_node_slot(root, path->nodes[1], slot - 1);
2015         btrfs_tree_lock(left);
2016         free_space = btrfs_leaf_free_space(root, left);
2017         if (free_space < data_size + sizeof(struct btrfs_item)) {
2018                 ret = 1;
2019                 goto out;
2020         }
2021
2022         /* cow and double check */
2023         ret = btrfs_cow_block(trans, root, left,
2024                               path->nodes[1], slot - 1, &left);
2025         if (ret) {
2026                 /* we hit -ENOSPC, but it isn't fatal here */
2027                 ret = 1;
2028                 goto out;
2029         }
2030
2031         free_space = btrfs_leaf_free_space(root, left);
2032         if (free_space < data_size + sizeof(struct btrfs_item)) {
2033                 ret = 1;
2034                 goto out;
2035         }
2036
2037         if (empty)
2038                 nr = right_nritems;
2039         else
2040                 nr = right_nritems - 1;
2041
2042         for (i = 0; i < nr; i++) {
2043                 item = btrfs_item_nr(right, i);
2044                 if (!right->map_token) {
2045                         map_extent_buffer(right, (unsigned long)item,
2046                                         sizeof(struct btrfs_item),
2047                                         &right->map_token, &right->kaddr,
2048                                         &right->map_start, &right->map_len,
2049                                         KM_USER1);
2050                 }
2051
2052                 if (path->slots[0] == i)
2053                         push_space += data_size + sizeof(*item);
2054
2055                 this_item_size = btrfs_item_size(right, item);
2056                 if (this_item_size + sizeof(*item) + push_space > free_space)
2057                         break;
2058
2059                 push_items++;
2060                 push_space += this_item_size + sizeof(*item);
2061         }
2062
2063         if (right->map_token) {
2064                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2065                 right->map_token = NULL;
2066         }
2067
2068         if (push_items == 0) {
2069                 ret = 1;
2070                 goto out;
2071         }
2072         if (!empty && push_items == btrfs_header_nritems(right))
2073                 WARN_ON(1);
2074
2075         /* push data from right to left */
2076         copy_extent_buffer(left, right,
2077                            btrfs_item_nr_offset(btrfs_header_nritems(left)),
2078                            btrfs_item_nr_offset(0),
2079                            push_items * sizeof(struct btrfs_item));
2080
2081         push_space = BTRFS_LEAF_DATA_SIZE(root) -
2082                      btrfs_item_offset_nr(right, push_items -1);
2083
2084         copy_extent_buffer(left, right, btrfs_leaf_data(left) +
2085                      leaf_data_end(root, left) - push_space,
2086                      btrfs_leaf_data(right) +
2087                      btrfs_item_offset_nr(right, push_items - 1),
2088                      push_space);
2089         old_left_nritems = btrfs_header_nritems(left);
2090         BUG_ON(old_left_nritems < 0);
2091
2092         old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
2093         for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
2094                 u32 ioff;
2095
2096                 item = btrfs_item_nr(left, i);
2097                 if (!left->map_token) {
2098                         map_extent_buffer(left, (unsigned long)item,
2099                                         sizeof(struct btrfs_item),
2100                                         &left->map_token, &left->kaddr,
2101                                         &left->map_start, &left->map_len,
2102                                         KM_USER1);
2103                 }
2104
2105                 ioff = btrfs_item_offset(left, item);
2106                 btrfs_set_item_offset(left, item,
2107                       ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
2108         }
2109         btrfs_set_header_nritems(left, old_left_nritems + push_items);
2110         if (left->map_token) {
2111                 unmap_extent_buffer(left, left->map_token, KM_USER1);
2112                 left->map_token = NULL;
2113         }
2114
2115         /* fixup right node */
2116         if (push_items > right_nritems) {
2117                 printk("push items %d nr %u\n", push_items, right_nritems);
2118                 WARN_ON(1);
2119         }
2120
2121         if (push_items < right_nritems) {
2122                 push_space = btrfs_item_offset_nr(right, push_items - 1) -
2123                                                   leaf_data_end(root, right);
2124                 memmove_extent_buffer(right, btrfs_leaf_data(right) +
2125                                       BTRFS_LEAF_DATA_SIZE(root) - push_space,
2126                                       btrfs_leaf_data(right) +
2127                                       leaf_data_end(root, right), push_space);
2128
2129                 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
2130                               btrfs_item_nr_offset(push_items),
2131                              (btrfs_header_nritems(right) - push_items) *
2132                              sizeof(struct btrfs_item));
2133         }
2134         right_nritems -= push_items;
2135         btrfs_set_header_nritems(right, right_nritems);
2136         push_space = BTRFS_LEAF_DATA_SIZE(root);
2137         for (i = 0; i < right_nritems; i++) {
2138                 item = btrfs_item_nr(right, i);
2139
2140                 if (!right->map_token) {
2141                         map_extent_buffer(right, (unsigned long)item,
2142                                         sizeof(struct btrfs_item),
2143                                         &right->map_token, &right->kaddr,
2144                                         &right->map_start, &right->map_len,
2145                                         KM_USER1);
2146                 }
2147
2148                 push_space = push_space - btrfs_item_size(right, item);
2149                 btrfs_set_item_offset(right, item, push_space);
2150         }
2151         if (right->map_token) {
2152                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2153                 right->map_token = NULL;
2154         }
2155
2156         btrfs_mark_buffer_dirty(left);
2157         if (right_nritems)
2158                 btrfs_mark_buffer_dirty(right);
2159
2160         btrfs_item_key(right, &disk_key, 0);
2161         wret = fixup_low_keys(trans, root, path, &disk_key, 1);
2162         if (wret)
2163                 ret = wret;
2164
2165         /* then fixup the leaf pointer in the path */
2166         if (path->slots[0] < push_items) {
2167                 path->slots[0] += old_left_nritems;
2168                 if (btrfs_header_nritems(path->nodes[0]) == 0)
2169                         clean_tree_block(trans, root, path->nodes[0]);
2170                 btrfs_tree_unlock(path->nodes[0]);
2171                 free_extent_buffer(path->nodes[0]);
2172                 path->nodes[0] = left;
2173                 path->slots[1] -= 1;
2174         } else {
2175                 btrfs_tree_unlock(left);
2176                 free_extent_buffer(left);
2177                 path->slots[0] -= push_items;
2178         }
2179         BUG_ON(path->slots[0] < 0);
2180         return ret;
2181 out:
2182         btrfs_tree_unlock(left);
2183         free_extent_buffer(left);
2184         return ret;
2185 }
2186
2187 /*
2188  * split the path's leaf in two, making sure there is at least data_size
2189  * available for the resulting leaf level of the path.
2190  *
2191  * returns 0 if all went well and < 0 on failure.
2192  */
2193 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
2194                       *root, struct btrfs_key *ins_key,
2195                       struct btrfs_path *path, int data_size, int extend)
2196 {
2197         u64 root_gen;
2198         struct extent_buffer *l;
2199         u32 nritems;
2200         int mid;
2201         int slot;
2202         struct extent_buffer *right;
2203         int space_needed = data_size + sizeof(struct btrfs_item);
2204         int data_copy_size;
2205         int rt_data_off;
2206         int i;
2207         int ret = 0;
2208         int wret;
2209         int double_split;
2210         int num_doubles = 0;
2211         struct btrfs_disk_key disk_key;
2212
2213         if (extend)
2214                 space_needed = data_size;
2215
2216         if (root->ref_cows)
2217                 root_gen = trans->transid;
2218         else
2219                 root_gen = 0;
2220
2221         /* first try to make some room by pushing left and right */
2222         if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
2223                 wret = push_leaf_right(trans, root, path, data_size, 0);
2224                 if (wret < 0) {
2225                         return wret;
2226                 }
2227                 if (wret) {
2228                         wret = push_leaf_left(trans, root, path, data_size, 0);
2229                         if (wret < 0)
2230                                 return wret;
2231                 }
2232                 l = path->nodes[0];
2233
2234                 /* did the pushes work? */
2235                 if (btrfs_leaf_free_space(root, l) >= space_needed)
2236                         return 0;
2237         }
2238
2239         if (!path->nodes[1]) {
2240                 ret = insert_new_root(trans, root, path, 1);
2241                 if (ret)
2242                         return ret;
2243         }
2244 again:
2245         double_split = 0;
2246         l = path->nodes[0];
2247         slot = path->slots[0];
2248         nritems = btrfs_header_nritems(l);
2249         mid = (nritems + 1)/ 2;
2250
2251         btrfs_item_key(l, &disk_key, 0);
2252
2253         right = btrfs_alloc_free_block(trans, root, root->leafsize,
2254                                          root->root_key.objectid,
2255                                          root_gen, disk_key.objectid, 0,
2256                                          l->start, 0);
2257         if (IS_ERR(right)) {
2258                 BUG_ON(1);
2259                 return PTR_ERR(right);
2260         }
2261
2262         memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2263         btrfs_set_header_bytenr(right, right->start);
2264         btrfs_set_header_generation(right, trans->transid);
2265         btrfs_set_header_owner(right, root->root_key.objectid);
2266         btrfs_set_header_level(right, 0);
2267         write_extent_buffer(right, root->fs_info->fsid,
2268                             (unsigned long)btrfs_header_fsid(right),
2269                             BTRFS_FSID_SIZE);
2270
2271         write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2272                             (unsigned long)btrfs_header_chunk_tree_uuid(right),
2273                             BTRFS_UUID_SIZE);
2274         if (mid <= slot) {
2275                 if (nritems == 1 ||
2276                     leaf_space_used(l, mid, nritems - mid) + space_needed >
2277                         BTRFS_LEAF_DATA_SIZE(root)) {
2278                         if (slot >= nritems) {
2279                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2280                                 btrfs_set_header_nritems(right, 0);
2281                                 wret = insert_ptr(trans, root, path,
2282                                                   &disk_key, right->start,
2283                                                   path->slots[1] + 1, 1);
2284                                 if (wret)
2285                                         ret = wret;
2286
2287                                 btrfs_tree_unlock(path->nodes[0]);
2288                                 free_extent_buffer(path->nodes[0]);
2289                                 path->nodes[0] = right;
2290                                 path->slots[0] = 0;
2291                                 path->slots[1] += 1;
2292                                 btrfs_mark_buffer_dirty(right);
2293                                 return ret;
2294                         }
2295                         mid = slot;
2296                         if (mid != nritems &&
2297                             leaf_space_used(l, mid, nritems - mid) +
2298                             space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2299                                 double_split = 1;
2300                         }
2301                 }
2302         } else {
2303                 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2304                         BTRFS_LEAF_DATA_SIZE(root)) {
2305                         if (!extend && slot == 0) {
2306                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2307                                 btrfs_set_header_nritems(right, 0);
2308                                 wret = insert_ptr(trans, root, path,
2309                                                   &disk_key,
2310                                                   right->start,
2311                                                   path->slots[1], 1);
2312                                 if (wret)
2313                                         ret = wret;
2314                                 btrfs_tree_unlock(path->nodes[0]);
2315                                 free_extent_buffer(path->nodes[0]);
2316                                 path->nodes[0] = right;
2317                                 path->slots[0] = 0;
2318                                 if (path->slots[1] == 0) {
2319                                         wret = fixup_low_keys(trans, root,
2320                                                    path, &disk_key, 1);
2321                                         if (wret)
2322                                                 ret = wret;
2323                                 }
2324                                 btrfs_mark_buffer_dirty(right);
2325                                 return ret;
2326                         } else if (extend && slot == 0) {
2327                                 mid = 1;
2328                         } else {
2329                                 mid = slot;
2330                                 if (mid != nritems &&
2331                                     leaf_space_used(l, mid, nritems - mid) +
2332                                     space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2333                                         double_split = 1;
2334                                 }
2335                         }
2336                 }
2337         }
2338         nritems = nritems - mid;
2339         btrfs_set_header_nritems(right, nritems);
2340         data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2341
2342         copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2343                            btrfs_item_nr_offset(mid),
2344                            nritems * sizeof(struct btrfs_item));
2345
2346         copy_extent_buffer(right, l,
2347                      btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2348                      data_copy_size, btrfs_leaf_data(l) +
2349                      leaf_data_end(root, l), data_copy_size);
2350
2351         rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2352                       btrfs_item_end_nr(l, mid);
2353
2354         for (i = 0; i < nritems; i++) {
2355                 struct btrfs_item *item = btrfs_item_nr(right, i);
2356                 u32 ioff;
2357
2358                 if (!right->map_token) {
2359                         map_extent_buffer(right, (unsigned long)item,
2360                                         sizeof(struct btrfs_item),
2361                                         &right->map_token, &right->kaddr,
2362                                         &right->map_start, &right->map_len,
2363                                         KM_USER1);
2364                 }
2365
2366                 ioff = btrfs_item_offset(right, item);
2367                 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2368         }
2369
2370         if (right->map_token) {
2371                 unmap_extent_buffer(right, right->map_token, KM_USER1);
2372                 right->map_token = NULL;
2373         }
2374
2375         btrfs_set_header_nritems(l, mid);
2376         ret = 0;
2377         btrfs_item_key(right, &disk_key, 0);
2378         wret = insert_ptr(trans, root, path, &disk_key, right->start,
2379                           path->slots[1] + 1, 1);
2380         if (wret)
2381                 ret = wret;
2382
2383         btrfs_mark_buffer_dirty(right);
2384         btrfs_mark_buffer_dirty(l);
2385         BUG_ON(path->slots[0] != slot);
2386
2387         if (mid <= slot) {
2388                 btrfs_tree_unlock(path->nodes[0]);
2389                 free_extent_buffer(path->nodes[0]);
2390                 path->nodes[0] = right;
2391                 path->slots[0] -= mid;
2392                 path->slots[1] += 1;
2393         } else {
2394                 btrfs_tree_unlock(right);
2395                 free_extent_buffer(right);
2396         }
2397
2398         BUG_ON(path->slots[0] < 0);
2399
2400         if (double_split) {
2401                 BUG_ON(num_doubles != 0);
2402                 num_doubles++;
2403                 goto again;
2404         }
2405         return ret;
2406 }
2407
2408 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2409                         struct btrfs_root *root,
2410                         struct btrfs_path *path,
2411                         u32 new_size, int from_end)
2412 {
2413         int ret = 0;
2414         int slot;
2415         int slot_orig;
2416         struct extent_buffer *leaf;
2417         struct btrfs_item *item;
2418         u32 nritems;
2419         unsigned int data_end;
2420         unsigned int old_data_start;
2421         unsigned int old_size;
2422         unsigned int size_diff;
2423         int i;
2424
2425         slot_orig = path->slots[0];
2426         leaf = path->nodes[0];
2427         slot = path->slots[0];
2428
2429         old_size = btrfs_item_size_nr(leaf, slot);
2430         if (old_size == new_size)
2431                 return 0;
2432
2433         nritems = btrfs_header_nritems(leaf);
2434         data_end = leaf_data_end(root, leaf);
2435
2436         old_data_start = btrfs_item_offset_nr(leaf, slot);
2437
2438         size_diff = old_size - new_size;
2439
2440         BUG_ON(slot < 0);
2441         BUG_ON(slot >= nritems);
2442
2443         /*
2444          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2445          */
2446         /* first correct the data pointers */
2447         for (i = slot; i < nritems; i++) {
2448                 u32 ioff;
2449                 item = btrfs_item_nr(leaf, i);
2450
2451                 if (!leaf->map_token) {
2452                         map_extent_buffer(leaf, (unsigned long)item,
2453                                         sizeof(struct btrfs_item),
2454                                         &leaf->map_token, &leaf->kaddr,
2455                                         &leaf->map_start, &leaf->map_len,
2456                                         KM_USER1);
2457                 }
2458
2459                 ioff = btrfs_item_offset(leaf, item);
2460                 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2461         }
2462
2463         if (leaf->map_token) {
2464                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2465                 leaf->map_token = NULL;
2466         }
2467
2468         /* shift the data */
2469         if (from_end) {
2470                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2471                               data_end + size_diff, btrfs_leaf_data(leaf) +
2472                               data_end, old_data_start + new_size - data_end);
2473         } else {
2474                 struct btrfs_disk_key disk_key;
2475                 u64 offset;
2476
2477                 btrfs_item_key(leaf, &disk_key, slot);
2478
2479                 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2480                         unsigned long ptr;
2481                         struct btrfs_file_extent_item *fi;
2482
2483                         fi = btrfs_item_ptr(leaf, slot,
2484                                             struct btrfs_file_extent_item);
2485                         fi = (struct btrfs_file_extent_item *)(
2486                              (unsigned long)fi - size_diff);
2487
2488                         if (btrfs_file_extent_type(leaf, fi) ==
2489                             BTRFS_FILE_EXTENT_INLINE) {
2490                                 ptr = btrfs_item_ptr_offset(leaf, slot);
2491                                 memmove_extent_buffer(leaf, ptr,
2492                                         (unsigned long)fi,
2493                                         offsetof(struct btrfs_file_extent_item,
2494                                                  disk_bytenr));
2495                         }
2496                 }
2497
2498                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2499                               data_end + size_diff, btrfs_leaf_data(leaf) +
2500                               data_end, old_data_start - data_end);
2501
2502                 offset = btrfs_disk_key_offset(&disk_key);
2503                 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2504                 btrfs_set_item_key(leaf, &disk_key, slot);
2505                 if (slot == 0)
2506                         fixup_low_keys(trans, root, path, &disk_key, 1);
2507         }
2508
2509         item = btrfs_item_nr(leaf, slot);
2510         btrfs_set_item_size(leaf, item, new_size);
2511         btrfs_mark_buffer_dirty(leaf);
2512
2513         ret = 0;
2514         if (btrfs_leaf_free_space(root, leaf) < 0) {
2515                 btrfs_print_leaf(root, leaf);
2516                 BUG();
2517         }
2518         return ret;
2519 }
2520
2521 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2522                       struct btrfs_root *root, struct btrfs_path *path,
2523                       u32 data_size)
2524 {
2525         int ret = 0;
2526         int slot;
2527         int slot_orig;
2528         struct extent_buffer *leaf;
2529         struct btrfs_item *item;
2530         u32 nritems;
2531         unsigned int data_end;
2532         unsigned int old_data;
2533         unsigned int old_size;
2534         int i;
2535
2536         slot_orig = path->slots[0];
2537         leaf = path->nodes[0];
2538
2539         nritems = btrfs_header_nritems(leaf);
2540         data_end = leaf_data_end(root, leaf);
2541
2542         if (btrfs_leaf_free_space(root, leaf) < data_size) {
2543                 btrfs_print_leaf(root, leaf);
2544                 BUG();
2545         }
2546         slot = path->slots[0];
2547         old_data = btrfs_item_end_nr(leaf, slot);
2548
2549         BUG_ON(slot < 0);
2550         if (slot >= nritems) {
2551                 btrfs_print_leaf(root, leaf);
2552                 printk("slot %d too large, nritems %d\n", slot, nritems);
2553                 BUG_ON(1);
2554         }
2555
2556         /*
2557          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2558          */
2559         /* first correct the data pointers */
2560         for (i = slot; i < nritems; i++) {
2561                 u32 ioff;
2562                 item = btrfs_item_nr(leaf, i);
2563
2564                 if (!leaf->map_token) {
2565                         map_extent_buffer(leaf, (unsigned long)item,
2566                                         sizeof(struct btrfs_item),
2567                                         &leaf->map_token, &leaf->kaddr,
2568                                         &leaf->map_start, &leaf->map_len,
2569                                         KM_USER1);
2570                 }
2571                 ioff = btrfs_item_offset(leaf, item);
2572                 btrfs_set_item_offset(leaf, item, ioff - data_size);
2573         }
2574
2575         if (leaf->map_token) {
2576                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2577                 leaf->map_token = NULL;
2578         }
2579
2580         /* shift the data */
2581         memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2582                       data_end - data_size, btrfs_leaf_data(leaf) +
2583                       data_end, old_data - data_end);
2584
2585         data_end = old_data;
2586         old_size = btrfs_item_size_nr(leaf, slot);
2587         item = btrfs_item_nr(leaf, slot);
2588         btrfs_set_item_size(leaf, item, old_size + data_size);
2589         btrfs_mark_buffer_dirty(leaf);
2590
2591         ret = 0;
2592         if (btrfs_leaf_free_space(root, leaf) < 0) {
2593                 btrfs_print_leaf(root, leaf);
2594                 BUG();
2595         }
2596         return ret;
2597 }
2598
2599 /*
2600  * Given a key and some data, insert an item into the tree.
2601  * This does all the path init required, making room in the tree if needed.
2602  */
2603 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2604                             struct btrfs_root *root,
2605                             struct btrfs_path *path,
2606                             struct btrfs_key *cpu_key, u32 *data_size,
2607                             int nr)
2608 {
2609         struct extent_buffer *leaf;
2610         struct btrfs_item *item;
2611         int ret = 0;
2612         int slot;
2613         int slot_orig;
2614         int i;
2615         u32 nritems;
2616         u32 total_size = 0;
2617         u32 total_data = 0;
2618         unsigned int data_end;
2619         struct btrfs_disk_key disk_key;
2620
2621         for (i = 0; i < nr; i++) {
2622                 total_data += data_size[i];
2623         }
2624
2625         total_size = total_data + (nr * sizeof(struct btrfs_item));
2626         ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2627         if (ret == 0) {
2628                 return -EEXIST;
2629         }
2630         if (ret < 0)
2631                 goto out;
2632
2633         slot_orig = path->slots[0];
2634         leaf = path->nodes[0];
2635
2636         nritems = btrfs_header_nritems(leaf);
2637         data_end = leaf_data_end(root, leaf);
2638
2639         if (btrfs_leaf_free_space(root, leaf) <
2640             sizeof(struct btrfs_item) + total_size) {
2641                 btrfs_print_leaf(root, leaf);
2642                 printk("not enough freespace need %u have %d\n",
2643                        total_size, btrfs_leaf_free_space(root, leaf));
2644                 BUG();
2645         }
2646
2647         slot = path->slots[0];
2648         BUG_ON(slot < 0);
2649
2650         if (slot != nritems) {
2651                 int i;
2652                 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2653
2654                 if (old_data < data_end) {
2655                         btrfs_print_leaf(root, leaf);
2656                         printk("slot %d old_data %d data_end %d\n",
2657                                slot, old_data, data_end);
2658                         BUG_ON(1);
2659                 }
2660                 /*
2661                  * item0..itemN ... dataN.offset..dataN.size .. data0.size
2662                  */
2663                 /* first correct the data pointers */
2664                 WARN_ON(leaf->map_token);
2665                 for (i = slot; i < nritems; i++) {
2666                         u32 ioff;
2667
2668                         item = btrfs_item_nr(leaf, i);
2669                         if (!leaf->map_token) {
2670                                 map_extent_buffer(leaf, (unsigned long)item,
2671                                         sizeof(struct btrfs_item),
2672                                         &leaf->map_token, &leaf->kaddr,
2673                                         &leaf->map_start, &leaf->map_len,
2674                                         KM_USER1);
2675                         }
2676
2677                         ioff = btrfs_item_offset(leaf, item);
2678                         btrfs_set_item_offset(leaf, item, ioff - total_data);
2679                 }
2680                 if (leaf->map_token) {
2681                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2682                         leaf->map_token = NULL;
2683                 }
2684
2685                 /* shift the items */
2686                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2687                               btrfs_item_nr_offset(slot),
2688                               (nritems - slot) * sizeof(struct btrfs_item));
2689
2690                 /* shift the data */
2691                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2692                               data_end - total_data, btrfs_leaf_data(leaf) +
2693                               data_end, old_data - data_end);
2694                 data_end = old_data;
2695         }
2696
2697         /* setup the item for the new data */
2698         for (i = 0; i < nr; i++) {
2699                 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2700                 btrfs_set_item_key(leaf, &disk_key, slot + i);
2701                 item = btrfs_item_nr(leaf, slot + i);
2702                 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2703                 data_end -= data_size[i];
2704                 btrfs_set_item_size(leaf, item, data_size[i]);
2705         }
2706         btrfs_set_header_nritems(leaf, nritems + nr);
2707         btrfs_mark_buffer_dirty(leaf);
2708
2709         ret = 0;
2710         if (slot == 0) {
2711                 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2712                 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2713         }
2714
2715         if (btrfs_leaf_free_space(root, leaf) < 0) {
2716                 btrfs_print_leaf(root, leaf);
2717                 BUG();
2718         }
2719 out:
2720         return ret;
2721 }
2722
2723 /*
2724  * Given a key and some data, insert an item into the tree.
2725  * This does all the path init required, making room in the tree if needed.
2726  */
2727 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2728                       *root, struct btrfs_key *cpu_key, void *data, u32
2729                       data_size)
2730 {
2731         int ret = 0;
2732         struct btrfs_path *path;
2733         struct extent_buffer *leaf;
2734         unsigned long ptr;
2735
2736         path = btrfs_alloc_path();
2737         BUG_ON(!path);
2738         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2739         if (!ret) {
2740                 leaf = path->nodes[0];
2741                 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2742                 write_extent_buffer(leaf, data, ptr, data_size);
2743                 btrfs_mark_buffer_dirty(leaf);
2744         }
2745         btrfs_free_path(path);
2746         return ret;
2747 }
2748
2749 /*
2750  * delete the pointer from a given node.
2751  *
2752  * If the delete empties a node, the node is removed from the tree,
2753  * continuing all the way the root if required.  The root is converted into
2754  * a leaf if all the nodes are emptied.
2755  */
2756 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2757                    struct btrfs_path *path, int level, int slot)
2758 {
2759         struct extent_buffer *parent = path->nodes[level];
2760         u32 nritems;
2761         int ret = 0;
2762         int wret;
2763
2764         nritems = btrfs_header_nritems(parent);
2765         if (slot != nritems -1) {
2766                 memmove_extent_buffer(parent,
2767                               btrfs_node_key_ptr_offset(slot),
2768                               btrfs_node_key_ptr_offset(slot + 1),
2769                               sizeof(struct btrfs_key_ptr) *
2770                               (nritems - slot - 1));
2771         }
2772         nritems--;
2773         btrfs_set_header_nritems(parent, nritems);
2774         if (nritems == 0 && parent == root->node) {
2775                 BUG_ON(btrfs_header_level(root->node) != 1);
2776                 /* just turn the root into a leaf and break */
2777                 btrfs_set_header_level(root->node, 0);
2778         } else if (slot == 0) {
2779                 struct btrfs_disk_key disk_key;
2780
2781                 btrfs_node_key(parent, &disk_key, 0);
2782                 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2783                 if (wret)
2784                         ret = wret;
2785         }
2786         btrfs_mark_buffer_dirty(parent);
2787         return ret;
2788 }
2789
2790 /*
2791  * delete the item at the leaf level in path.  If that empties
2792  * the leaf, remove it from the tree
2793  */
2794 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2795                     struct btrfs_path *path, int slot, int nr)
2796 {
2797         struct extent_buffer *leaf;
2798         struct btrfs_item *item;
2799         int last_off;
2800         int dsize = 0;
2801         int ret = 0;
2802         int wret;
2803         int i;
2804         u32 nritems;
2805
2806         leaf = path->nodes[0];
2807         last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2808
2809         for (i = 0; i < nr; i++)
2810                 dsize += btrfs_item_size_nr(leaf, slot + i);
2811
2812         nritems = btrfs_header_nritems(leaf);
2813
2814         if (slot + nr != nritems) {
2815                 int i;
2816                 int data_end = leaf_data_end(root, leaf);
2817
2818                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2819                               data_end + dsize,
2820                               btrfs_leaf_data(leaf) + data_end,
2821                               last_off - data_end);
2822
2823                 for (i = slot + nr; i < nritems; i++) {
2824                         u32 ioff;
2825
2826                         item = btrfs_item_nr(leaf, i);
2827                         if (!leaf->map_token) {
2828                                 map_extent_buffer(leaf, (unsigned long)item,
2829                                         sizeof(struct btrfs_item),
2830                                         &leaf->map_token, &leaf->kaddr,
2831                                         &leaf->map_start, &leaf->map_len,
2832                                         KM_USER1);
2833                         }
2834                         ioff = btrfs_item_offset(leaf, item);
2835                         btrfs_set_item_offset(leaf, item, ioff + dsize);
2836                 }
2837
2838                 if (leaf->map_token) {
2839                         unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2840                         leaf->map_token = NULL;
2841                 }
2842
2843                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2844                               btrfs_item_nr_offset(slot + nr),
2845                               sizeof(struct btrfs_item) *
2846                               (nritems - slot - nr));
2847         }
2848         btrfs_set_header_nritems(leaf, nritems - nr);
2849         nritems -= nr;
2850
2851         /* delete the leaf if we've emptied it */
2852         if (nritems == 0) {
2853                 if (leaf == root->node) {
2854                         btrfs_set_header_level(leaf, 0);
2855                 } else {
2856                         u64 root_gen = btrfs_header_generation(path->nodes[1]);
2857                         wret = del_ptr(trans, root, path, 1, path->slots[1]);
2858                         if (wret)
2859                                 ret = wret;
2860                         wret = btrfs_free_extent(trans, root,
2861                                          leaf->start, leaf->len,
2862                                          btrfs_header_owner(path->nodes[1]),
2863                                          root_gen, 0, 0, 1);
2864                         if (wret)
2865                                 ret = wret;
2866                 }
2867         } else {
2868                 int used = leaf_space_used(leaf, 0, nritems);
2869                 if (slot == 0) {
2870                         struct btrfs_disk_key disk_key;
2871
2872                         btrfs_item_key(leaf, &disk_key, 0);
2873                         wret = fixup_low_keys(trans, root, path,
2874                                               &disk_key, 1);
2875                         if (wret)
2876                                 ret = wret;
2877                 }
2878
2879                 /* delete the leaf if it is mostly empty */
2880                 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2881                         /* push_leaf_left fixes the path.
2882                          * make sure the path still points to our leaf
2883                          * for possible call to del_ptr below
2884                          */
2885                         slot = path->slots[1];
2886                         extent_buffer_get(leaf);
2887
2888                         wret = push_leaf_left(trans, root, path, 1, 1);
2889                         if (wret < 0 && wret != -ENOSPC)
2890                                 ret = wret;
2891
2892                         if (path->nodes[0] == leaf &&
2893                             btrfs_header_nritems(leaf)) {
2894                                 wret = push_leaf_right(trans, root, path, 1, 1);
2895                                 if (wret < 0 && wret != -ENOSPC)
2896                                         ret = wret;
2897                         }
2898
2899                         if (btrfs_header_nritems(leaf) == 0) {
2900                                 u64 root_gen;
2901                                 u64 bytenr = leaf->start;
2902                                 u32 blocksize = leaf->len;
2903
2904                                 root_gen = btrfs_header_generation(
2905                                                            path->nodes[1]);
2906
2907                                 wret = del_ptr(trans, root, path, 1, slot);
2908                                 if (wret)
2909                                         ret = wret;
2910
2911                                 free_extent_buffer(leaf);
2912                                 wret = btrfs_free_extent(trans, root, bytenr,
2913                                              blocksize,
2914                                              btrfs_header_owner(path->nodes[1]),
2915                                              root_gen, 0, 0, 1);
2916                                 if (wret)
2917                                         ret = wret;
2918                         } else {
2919                                 /* if we're still in the path, make sure
2920                                  * we're dirty.  Otherwise, one of the
2921                                  * push_leaf functions must have already
2922                                  * dirtied this buffer
2923                                  */
2924                                 if (path->nodes[0] == leaf)
2925                                         btrfs_mark_buffer_dirty(leaf);
2926                                 free_extent_buffer(leaf);
2927                         }
2928                 } else {
2929                         btrfs_mark_buffer_dirty(leaf);
2930                 }
2931         }
2932         return ret;
2933 }
2934
2935 /*
2936  * search the tree again to find a leaf with lesser keys
2937  * returns 0 if it found something or 1 if there are no lesser leaves.
2938  * returns < 0 on io errors.
2939  */
2940 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2941 {
2942         struct btrfs_key key;
2943         struct btrfs_disk_key found_key;
2944         int ret;
2945
2946         btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
2947
2948         if (key.offset > 0)
2949                 key.offset--;
2950         else if (key.type > 0)
2951                 key.type--;
2952         else if (key.objectid > 0)
2953                 key.objectid--;
2954         else
2955                 return 1;
2956
2957         btrfs_release_path(root, path);
2958         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2959         if (ret < 0)
2960                 return ret;
2961         btrfs_item_key(path->nodes[0], &found_key, 0);
2962         ret = comp_keys(&found_key, &key);
2963         if (ret < 0)
2964                 return 0;
2965         return 1;
2966 }
2967
2968 /*
2969  * A helper function to walk down the tree starting at min_key, and looking
2970  * for nodes or leaves that are either in cache or have a minimum
2971  * transaction id.  This is used by the btree defrag code, but could
2972  * also be used to search for blocks that have changed since a given
2973  * transaction id.
2974  *
2975  * This does not cow, but it does stuff the starting key it finds back
2976  * into min_key, so you can call btrfs_search_slot with cow=1 on the
2977  * key and get a writable path.
2978  *
2979  * This does lock as it descends, and path->keep_locks should be set
2980  * to 1 by the caller.
2981  *
2982  * This honors path->lowest_level to prevent descent past a given level
2983  * of the tree.
2984  *
2985  * returns zero if something useful was found, < 0 on error and 1 if there
2986  * was nothing in the tree that matched the search criteria.
2987  */
2988 int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
2989                          struct btrfs_path *path, int cache_only,
2990                          u64 min_trans)
2991 {
2992         struct extent_buffer *cur;
2993         struct btrfs_key found_key;
2994         int slot;
2995         u32 nritems;
2996         int level;
2997         int ret = 1;
2998
2999 again:
3000         cur = btrfs_lock_root_node(root);
3001         level = btrfs_header_level(cur);
3002         path->nodes[level] = cur;
3003         path->locks[level] = 1;
3004
3005         if (btrfs_header_generation(cur) < min_trans) {
3006                 ret = 1;
3007                 goto out;
3008         }
3009         while(1) {
3010                 nritems = btrfs_header_nritems(cur);
3011                 level = btrfs_header_level(cur);
3012                 bin_search(cur, min_key, level, &slot);
3013
3014                 /* at level = 0, we're done, setup the path and exit */
3015                 if (level == 0) {
3016                         ret = 0;
3017                         path->slots[level] = slot;
3018                         btrfs_item_key_to_cpu(cur, &found_key, slot);
3019                         goto out;
3020                 }
3021                 /*
3022                  * check this node pointer against the cache_only and
3023                  * min_trans parameters.  If it isn't in cache or is too
3024                  * old, skip to the next one.
3025                  */
3026                 while(slot < nritems) {
3027                         u64 blockptr;
3028                         u64 gen;
3029                         struct extent_buffer *tmp;
3030                         blockptr = btrfs_node_blockptr(cur, slot);
3031                         gen = btrfs_node_ptr_generation(cur, slot);
3032                         if (gen < min_trans) {
3033                                 slot++;
3034                                 continue;
3035                         }
3036                         if (!cache_only)
3037                                 break;
3038
3039                         tmp = btrfs_find_tree_block(root, blockptr,
3040                                             btrfs_level_size(root, level - 1));
3041
3042                         if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
3043                                 free_extent_buffer(tmp);
3044                                 break;
3045                         }
3046                         if (tmp)
3047                                 free_extent_buffer(tmp);
3048                         slot++;
3049                 }
3050                 /*
3051                  * we didn't find a candidate key in this node, walk forward
3052                  * and find another one
3053                  */
3054                 if (slot >= nritems) {
3055                         ret = btrfs_find_next_key(root, path, min_key, level,
3056                                                   cache_only, min_trans);
3057                         if (ret == 0) {
3058                                 btrfs_release_path(root, path);
3059                                 goto again;
3060                         } else {
3061                                 goto out;
3062                         }
3063                 }
3064                 /* save our key for returning back */
3065                 btrfs_node_key_to_cpu(cur, &found_key, slot);
3066                 path->slots[level] = slot;
3067                 if (level == path->lowest_level) {
3068                         ret = 0;
3069                         unlock_up(path, level, 1);
3070                         goto out;
3071                 }
3072                 cur = read_node_slot(root, cur, slot);
3073
3074                 btrfs_tree_lock(cur);
3075                 path->locks[level - 1] = 1;
3076                 path->nodes[level - 1] = cur;
3077                 unlock_up(path, level, 1);
3078         }
3079 out:
3080         if (ret == 0)
3081                 memcpy(min_key, &found_key, sizeof(found_key));
3082         return ret;
3083 }
3084
3085 /*
3086  * this is similar to btrfs_next_leaf, but does not try to preserve
3087  * and fixup the path.  It looks for and returns the next key in the
3088  * tree based on the current path and the cache_only and min_trans
3089  * parameters.
3090  *
3091  * 0 is returned if another key is found, < 0 if there are any errors
3092  * and 1 is returned if there are no higher keys in the tree
3093  *
3094  * path->keep_locks should be set to 1 on the search made before
3095  * calling this function.
3096  */
3097 int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
3098                         struct btrfs_key *key, int lowest_level,
3099                         int cache_only, u64 min_trans)
3100 {
3101         int level = lowest_level;
3102         int slot;
3103         struct extent_buffer *c;
3104
3105         while(level < BTRFS_MAX_LEVEL) {
3106                 if (!path->nodes[level])
3107                         return 1;
3108
3109                 slot = path->slots[level] + 1;
3110                 c = path->nodes[level];
3111 next:
3112                 if (slot >= btrfs_header_nritems(c)) {
3113                         level++;
3114                         if (level == BTRFS_MAX_LEVEL) {
3115                                 return 1;
3116                         }
3117                         continue;
3118                 }
3119                 if (level == 0)
3120                         btrfs_item_key_to_cpu(c, key, slot);
3121                 else {
3122                         u64 blockptr = btrfs_node_blockptr(c, slot);
3123                         u64 gen = btrfs_node_ptr_generation(c, slot);
3124
3125                         if (cache_only) {
3126                                 struct extent_buffer *cur;
3127                                 cur = btrfs_find_tree_block(root, blockptr,
3128                                             btrfs_level_size(root, level - 1));
3129                                 if (!cur || !btrfs_buffer_uptodate(cur, gen)) {
3130                                         slot++;
3131                                         if (cur)
3132                                                 free_extent_buffer(cur);
3133                                         goto next;
3134                                 }
3135                                 free_extent_buffer(cur);
3136                         }
3137                         if (gen < min_trans) {
3138                                 slot++;
3139                                 goto next;
3140                         }
3141                         btrfs_node_key_to_cpu(c, key, slot);
3142                 }
3143                 return 0;
3144         }
3145         return 1;
3146 }
3147
3148 /*
3149  * search the tree again to find a leaf with greater keys
3150  * returns 0 if it found something or 1 if there are no greater leaves.
3151  * returns < 0 on io errors.
3152  */
3153 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
3154 {
3155         int slot;
3156         int level = 1;
3157         struct extent_buffer *c;
3158         struct extent_buffer *next = NULL;
3159         struct btrfs_key key;
3160         u32 nritems;
3161         int ret;
3162
3163         nritems = btrfs_header_nritems(path->nodes[0]);
3164         if (nritems == 0) {
3165                 return 1;
3166         }
3167
3168         btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
3169
3170         btrfs_release_path(root, path);
3171         path->keep_locks = 1;
3172         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3173         path->keep_locks = 0;
3174
3175         if (ret < 0)
3176                 return ret;
3177
3178         nritems = btrfs_header_nritems(path->nodes[0]);
3179         /*
3180          * by releasing the path above we dropped all our locks.  A balance
3181          * could have added more items next to the key that used to be
3182          * at the very end of the block.  So, check again here and
3183          * advance the path if there are now more items available.
3184          */
3185         if (nritems > 0 && path->slots[0] < nritems - 1) {
3186                 path->slots[0]++;
3187                 goto done;
3188         }
3189
3190         while(level < BTRFS_MAX_LEVEL) {
3191                 if (!path->nodes[level])
3192                         return 1;
3193
3194                 slot = path->slots[level] + 1;
3195                 c = path->nodes[level];
3196                 if (slot >= btrfs_header_nritems(c)) {
3197                         level++;
3198                         if (level == BTRFS_MAX_LEVEL) {
3199                                 return 1;
3200                         }
3201                         continue;
3202                 }
3203
3204                 if (next) {
3205                         btrfs_tree_unlock(next);
3206                         free_extent_buffer(next);
3207                 }
3208
3209                 if (level == 1 && (path->locks[1] || path->skip_locking) &&
3210                     path->reada)
3211                         reada_for_search(root, path, level, slot, 0);
3212
3213                 next = read_node_slot(root, c, slot);
3214                 if (!path->skip_locking) {
3215                         WARN_ON(!btrfs_tree_locked(c));
3216                         btrfs_tree_lock(next);
3217                 }
3218                 break;
3219         }
3220         path->slots[level] = slot;
3221         while(1) {
3222                 level--;
3223                 c = path->nodes[level];
3224                 if (path->locks[level])
3225                         btrfs_tree_unlock(c);
3226                 free_extent_buffer(c);
3227                 path->nodes[level] = next;
3228                 path->slots[level] = 0;
3229                 if (!path->skip_locking)
3230                         path->locks[level] = 1;
3231                 if (!level)
3232                         break;
3233                 if (level == 1 && path->locks[1] && path->reada)
3234                         reada_for_search(root, path, level, slot, 0);
3235                 next = read_node_slot(root, next, 0);
3236                 if (!path->skip_locking) {
3237                         WARN_ON(!btrfs_tree_locked(path->nodes[level]));
3238                         btrfs_tree_lock(next);
3239                 }
3240         }
3241 done:
3242         unlock_up(path, 0, 1);
3243         return 0;
3244 }
3245
3246 /*
3247  * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
3248  * searching until it gets past min_objectid or finds an item of 'type'
3249  *
3250  * returns 0 if something is found, 1 if nothing was found and < 0 on error
3251  */
3252 int btrfs_previous_item(struct btrfs_root *root,
3253                         struct btrfs_path *path, u64 min_objectid,
3254                         int type)
3255 {
3256         struct btrfs_key found_key;
3257         struct extent_buffer *leaf;
3258         int ret;
3259
3260         while(1) {
3261                 if (path->slots[0] == 0) {
3262                         ret = btrfs_prev_leaf(root, path);
3263                         if (ret != 0)
3264                                 return ret;
3265                 } else {
3266                         path->slots[0]--;
3267                 }
3268                 leaf = path->nodes[0];
3269                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3270                 if (found_key.type == type)
3271                         return 0;
3272         }
3273         return 1;
3274 }
3275