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 #include "ctree.h"
  19 #include "disk-io.h"
  20 #include "transaction.h"
  21 #include "print-tree.h"
  22 #include "repair.h"
  23 #include "internal.h"
  24 #include "sizes.h"
  25 #include "messages.h"
  26
  27 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
  28                       *root, struct btrfs_path *path, int level);
  29 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
  30                       *root, struct btrfs_key *ins_key,
  31                       struct btrfs_path *path, int data_size, int extend);
  32 static int push_node_left(struct btrfs_trans_handle *trans,
  33                           struct btrfs_root *root, struct extent_buffer *dst,
  34                           struct extent_buffer *src, int empty);
  35 static int balance_node_right(struct btrfs_trans_handle *trans,
  36                               struct btrfs_root *root,
  37                               struct extent_buffer *dst_buf,
  38                               struct extent_buffer *src_buf);
  39
  40 inline void btrfs_init_path(struct btrfs_path *p)
  41 {
  42         memset(p, 0, sizeof(*p));
  43 }
  44
  45 struct btrfs_path *btrfs_alloc_path(void)
  46 {
  47         struct btrfs_path *path;
  48         path = kzalloc(sizeof(struct btrfs_path), GFP_NOFS);
  49         return path;
  50 }
  51
  52 void btrfs_free_path(struct btrfs_path *p)
  53 {
  54         if (!p)
  55                 return;
  56         btrfs_release_path(p);
  57         kfree(p);
  58 }
  59
  60 void btrfs_release_path(struct btrfs_path *p)
  61 {
  62         int i;
  63         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
  64                 if (!p->nodes[i])
  65                         continue;
  66                 free_extent_buffer(p->nodes[i]);
  67         }
  68         memset(p, 0, sizeof(*p));
  69 }
  70
  71 void add_root_to_dirty_list(struct btrfs_root *root)
  72 {
  73         if (root->track_dirty && list_empty(&root->dirty_list)) {
  74                 list_add(&root->dirty_list,
  75                          &root->fs_info->dirty_cowonly_roots);
  76         }
  77 }
  78
  79 int btrfs_copy_root(struct btrfs_trans_handle *trans,
  80                       struct btrfs_root *root,
  81                       struct extent_buffer *buf,
  82                       struct extent_buffer **cow_ret, u64 new_root_objectid)
  83 {
  84         struct extent_buffer *cow;
  85         int ret = 0;
  86         int level;
  87         struct btrfs_root *new_root;
  88         struct btrfs_disk_key disk_key;
  89
  90         new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
  91         if (!new_root)
  92                 return -ENOMEM;
  93
  94         memcpy(new_root, root, sizeof(*new_root));
  95         new_root->root_key.objectid = new_root_objectid;
  96
  97         WARN_ON(root->ref_cows && trans->transid !=
  98                 root->fs_info->running_transaction->transid);
  99         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 100
 101         level = btrfs_header_level(buf);
 102         if (level == 0)
 103                 btrfs_item_key(buf, &disk_key, 0);
 104         else
 105                 btrfs_node_key(buf, &disk_key, 0);
 106         cow = btrfs_alloc_free_block(trans, new_root, buf->len,
 107                                      new_root_objectid, &disk_key,
 108                                      level, buf->start, 0);
 109         if (IS_ERR(cow)) {
 110                 kfree(new_root);
 111                 return PTR_ERR(cow);
 112         }
 113
 114         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 115         btrfs_set_header_bytenr(cow, cow->start);
 116         btrfs_set_header_generation(cow, trans->transid);
 117         btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
 118         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
 119                                      BTRFS_HEADER_FLAG_RELOC);
 120         if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
 121                 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
 122         else
 123                 btrfs_set_header_owner(cow, new_root_objectid);
 124
 125         write_extent_buffer(cow, root->fs_info->fsid,
 126                             btrfs_header_fsid(), BTRFS_FSID_SIZE);
 127
 128         WARN_ON(btrfs_header_generation(buf) > trans->transid);
 129         ret = btrfs_inc_ref(trans, new_root, cow, 0);
 130         kfree(new_root);
 131
 132         if (ret)
 133                 return ret;
 134
 135         btrfs_mark_buffer_dirty(cow);
 136         *cow_ret = cow;
 137         return 0;
 138 }
 139
 140 /*
 141  * check if the tree block can be shared by multiple trees
 142  */
 143 static int btrfs_block_can_be_shared(struct btrfs_root *root,
 144                                      struct extent_buffer *buf)
 145 {
 146         /*
 147          * Tree blocks not in reference counted trees and tree roots
 148          * are never shared. If a block was allocated after the last
 149          * snapshot and the block was not allocated by tree relocation,
 150          * we know the block is not shared.
 151          */
 152         if (root->ref_cows &&
 153             buf != root->node && buf != root->commit_root &&
 154             (btrfs_header_generation(buf) <=
 155              btrfs_root_last_snapshot(&root->root_item) ||
 156              btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
 157                 return 1;
 158 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 159         if (root->ref_cows &&
 160             btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
 161                 return 1;
 162 #endif
 163         return 0;
 164 }
 165
 166 static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
 167                                        struct btrfs_root *root,
 168                                        struct extent_buffer *buf,
 169                                        struct extent_buffer *cow)
 170 {
 171         u64 refs;
 172         u64 owner;
 173         u64 flags;
 174         u64 new_flags = 0;
 175         int ret;
 176
 177         /*
 178          * Backrefs update rules:
 179          *
 180          * Always use full backrefs for extent pointers in tree block
 181          * allocated by tree relocation.
 182          *
 183          * If a shared tree block is no longer referenced by its owner
 184          * tree (btrfs_header_owner(buf) == root->root_key.objectid),
 185          * use full backrefs for extent pointers in tree block.
 186          *
 187          * If a tree block is been relocating
 188          * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
 189          * use full backrefs for extent pointers in tree block.
 190          * The reason for this is some operations (such as drop tree)
 191          * are only allowed for blocks use full backrefs.
 192          */
 193
 194         if (btrfs_block_can_be_shared(root, buf)) {
 195                 ret = btrfs_lookup_extent_info(trans, root, buf->start,
 196                                                btrfs_header_level(buf), 1,
 197                                                &refs, &flags);
 198                 BUG_ON(ret);
 199                 BUG_ON(refs == 0);
 200         } else {
 201                 refs = 1;
 202                 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
 203                     btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
 204                         flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 205                 else
 206                         flags = 0;
 207         }
 208
 209         owner = btrfs_header_owner(buf);
 210         BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) &&
 211                owner == BTRFS_TREE_RELOC_OBJECTID);
 212
 213         if (refs > 1) {
 214                 if ((owner == root->root_key.objectid ||
 215                      root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
 216                     !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
 217                         ret = btrfs_inc_ref(trans, root, buf, 1);
 218                         BUG_ON(ret);
 219
 220                         if (root->root_key.objectid ==
 221                             BTRFS_TREE_RELOC_OBJECTID) {
 222                                 ret = btrfs_dec_ref(trans, root, buf, 0);
 223                                 BUG_ON(ret);
 224                                 ret = btrfs_inc_ref(trans, root, cow, 1);
 225                                 BUG_ON(ret);
 226                         }
 227                         new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
 228                 } else {
 229
 230                         if (root->root_key.objectid ==
 231                             BTRFS_TREE_RELOC_OBJECTID)
 232                                 ret = btrfs_inc_ref(trans, root, cow, 1);
 233                         else
 234                                 ret = btrfs_inc_ref(trans, root, cow, 0);
 235                         BUG_ON(ret);
 236                 }
 237                 if (new_flags != 0) {
 238                         ret = btrfs_set_block_flags(trans, root, buf->start,
 239                                                     btrfs_header_level(buf),
 240                                                     new_flags);
 241                         BUG_ON(ret);
 242                 }
 243         } else {
 244                 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
 245                         if (root->root_key.objectid ==
 246                             BTRFS_TREE_RELOC_OBJECTID)
 247                                 ret = btrfs_inc_ref(trans, root, cow, 1);
 248                         else
 249                                 ret = btrfs_inc_ref(trans, root, cow, 0);
 250                         BUG_ON(ret);
 251                         ret = btrfs_dec_ref(trans, root, buf, 1);
 252                         BUG_ON(ret);
 253                 }
 254                 clean_tree_block(trans, root, buf);
 255         }
 256         return 0;
 257 }
 258
 259 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 260                              struct btrfs_root *root,
 261                              struct extent_buffer *buf,
 262                              struct extent_buffer *parent, int parent_slot,
 263                              struct extent_buffer **cow_ret,
 264                              u64 search_start, u64 empty_size)
 265 {
 266         struct extent_buffer *cow;
 267         struct btrfs_disk_key disk_key;
 268         int level;
 269
 270         WARN_ON(root->ref_cows && trans->transid !=
 271                 root->fs_info->running_transaction->transid);
 272         WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 273
 274         level = btrfs_header_level(buf);
 275
 276         if (level == 0)
 277                 btrfs_item_key(buf, &disk_key, 0);
 278         else
 279                 btrfs_node_key(buf, &disk_key, 0);
 280
 281         cow = btrfs_alloc_free_block(trans, root, buf->len,
 282                                      root->root_key.objectid, &disk_key,
 283                                      level, search_start, empty_size);
 284         if (IS_ERR(cow))
 285                 return PTR_ERR(cow);
 286
 287         copy_extent_buffer(cow, buf, 0, 0, cow->len);
 288         btrfs_set_header_bytenr(cow, cow->start);
 289         btrfs_set_header_generation(cow, trans->transid);
 290         btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
 291         btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
 292                                      BTRFS_HEADER_FLAG_RELOC);
 293         if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
 294                 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
 295         else
 296                 btrfs_set_header_owner(cow, root->root_key.objectid);
 297
 298         write_extent_buffer(cow, root->fs_info->fsid,
 299                             btrfs_header_fsid(), BTRFS_FSID_SIZE);
 300
 301         WARN_ON(!(buf->flags & EXTENT_BAD_TRANSID) &&
 302                 btrfs_header_generation(buf) > trans->transid);
 303
 304         update_ref_for_cow(trans, root, buf, cow);
 305
 306         if (buf == root->node) {
 307                 root->node = cow;
 308                 extent_buffer_get(cow);
 309
 310                 btrfs_free_extent(trans, root, buf->start, buf->len,
 311                                   0, root->root_key.objectid, level, 0);
 312                 free_extent_buffer(buf);
 313                 add_root_to_dirty_list(root);
 314         } else {
 315                 btrfs_set_node_blockptr(parent, parent_slot,
 316                                         cow->start);
 317                 WARN_ON(trans->transid == 0);
 318                 btrfs_set_node_ptr_generation(parent, parent_slot,
 319                                               trans->transid);
 320                 btrfs_mark_buffer_dirty(parent);
 321                 WARN_ON(btrfs_header_generation(parent) != trans->transid);
 322
 323                 btrfs_free_extent(trans, root, buf->start, buf->len,
 324                                   0, root->root_key.objectid, level, 1);
 325         }
 326         if (!list_empty(&buf->recow)) {
 327                 list_del_init(&buf->recow);
 328                 free_extent_buffer(buf);
 329         }
 330         free_extent_buffer(buf);
 331         btrfs_mark_buffer_dirty(cow);
 332         *cow_ret = cow;
 333         return 0;
 334 }
 335
 336 static inline int should_cow_block(struct btrfs_trans_handle *trans,
 337                                    struct btrfs_root *root,
 338                                    struct extent_buffer *buf)
 339 {
 340         if (btrfs_header_generation(buf) == trans->transid &&
 341             !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
 342             !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
 343               btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
 344                 return 0;
 345         return 1;
 346 }
 347
 348 int btrfs_cow_block(struct btrfs_trans_handle *trans,
 349                     struct btrfs_root *root, struct extent_buffer *buf,
 350                     struct extent_buffer *parent, int parent_slot,
 351                     struct extent_buffer **cow_ret)
 352 {
 353         u64 search_start;
 354         int ret;
 355         /*
 356         if (trans->transaction != root->fs_info->running_transaction) {
 357                 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
 358                        root->fs_info->running_transaction->transid);
 359                 WARN_ON(1);
 360         }
 361         */
 362         if (trans->transid != root->fs_info->generation) {
 363                 printk(KERN_CRIT "trans %llu running %llu\n",
 364                         (unsigned long long)trans->transid,
 365                         (unsigned long long)root->fs_info->generation);
 366                 WARN_ON(1);
 367         }
 368         if (!should_cow_block(trans, root, buf)) {
 369                 *cow_ret = buf;
 370                 return 0;
 371         }
 372
 373         search_start = buf->start & ~((u64)SZ_1G - 1);
 374         ret = __btrfs_cow_block(trans, root, buf, parent,
 375                                  parent_slot, cow_ret, search_start, 0);
 376         return ret;
 377 }
 378
 379 int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2)
 380 {
 381         if (k1->objectid > k2->objectid)
 382                 return 1;
 383         if (k1->objectid < k2->objectid)
 384                 return -1;
 385         if (k1->type > k2->type)
 386                 return 1;
 387         if (k1->type < k2->type)
 388                 return -1;
 389         if (k1->offset > k2->offset)
 390                 return 1;
 391         if (k1->offset < k2->offset)
 392                 return -1;
 393         return 0;
 394 }
 395
 396 /*
 397  * compare two keys in a memcmp fashion
 398  */
 399 static int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
 400 {
 401         struct btrfs_key k1;
 402
 403         btrfs_disk_key_to_cpu(&k1, disk);
 404         return btrfs_comp_cpu_keys(&k1, k2);
 405 }
 406
 407 /*
 408  * The leaf data grows from end-to-front in the node.
 409  * this returns the address of the start of the last item,
 410  * which is the stop of the leaf data stack
 411  */
 412 static inline unsigned int leaf_data_end(const struct btrfs_fs_info *fs_info,
 413                                          const struct extent_buffer *leaf)
 414 {
 415         u32 nr = btrfs_header_nritems(leaf);
 416         if (nr == 0)
 417                 return BTRFS_LEAF_DATA_SIZE(fs_info);
 418         return btrfs_item_offset_nr(leaf, nr - 1);
 419 }
 420
 421 enum btrfs_tree_block_status
 422 btrfs_check_node(struct btrfs_root *root, struct btrfs_disk_key *parent_key,
 423                  struct extent_buffer *buf)
 424 {
 425         int i;
 426         struct btrfs_key cpukey;
 427         struct btrfs_disk_key key;
 428         u32 nritems = btrfs_header_nritems(buf);
 429         enum btrfs_tree_block_status ret = BTRFS_TREE_BLOCK_INVALID_NRITEMS;
 430
 431         if (nritems == 0 || nritems > BTRFS_NODEPTRS_PER_BLOCK(root->fs_info))
 432                 goto fail;
 433
 434         ret = BTRFS_TREE_BLOCK_INVALID_PARENT_KEY;
 435         if (parent_key && parent_key->type) {
 436                 btrfs_node_key(buf, &key, 0);
 437                 if (memcmp(parent_key, &key, sizeof(key)))
 438                         goto fail;
 439         }
 440         ret = BTRFS_TREE_BLOCK_BAD_KEY_ORDER;
 441         for (i = 0; nritems > 1 && i < nritems - 2; i++) {
 442                 btrfs_node_key(buf, &key, i);
 443                 btrfs_node_key_to_cpu(buf, &cpukey, i + 1);
 444                 if (btrfs_comp_keys(&key, &cpukey) >= 0)
 445                         goto fail;
 446         }
 447         return BTRFS_TREE_BLOCK_CLEAN;
 448 fail:
 449         if (btrfs_header_owner(buf) == BTRFS_EXTENT_TREE_OBJECTID) {
 450                 if (parent_key)
 451                         btrfs_disk_key_to_cpu(&cpukey, parent_key);
 452                 else
 453                         btrfs_node_key_to_cpu(buf, &cpukey, 0);
 454                 btrfs_add_corrupt_extent_record(root->fs_info, &cpukey,
 455                                                 buf->start, buf->len,
 456                                                 btrfs_header_level(buf));
 457         }
 458         return ret;
 459 }
 460
 461 enum btrfs_tree_block_status
 462 btrfs_check_leaf(struct btrfs_root *root, struct btrfs_disk_key *parent_key,
 463                  struct extent_buffer *buf)
 464 {
 465         int i;
 466         struct btrfs_key cpukey;
 467         struct btrfs_disk_key key;
 468         u32 nritems = btrfs_header_nritems(buf);
 469         enum btrfs_tree_block_status ret = BTRFS_TREE_BLOCK_INVALID_NRITEMS;
 470
 471         if (nritems * sizeof(struct btrfs_item) > buf->len)  {
 472                 fprintf(stderr, "invalid number of items %llu\n",
 473                         (unsigned long long)buf->start);
 474                 goto fail;
 475         }
 476
 477         if (btrfs_header_level(buf) != 0) {
 478                 ret = BTRFS_TREE_BLOCK_INVALID_LEVEL;
 479                 fprintf(stderr, "leaf is not a leaf %llu\n",
 480                        (unsigned long long)btrfs_header_bytenr(buf));
 481                 goto fail;
 482         }
 483         if (btrfs_leaf_free_space(root->fs_info, buf) < 0) {
 484                 ret = BTRFS_TREE_BLOCK_INVALID_FREE_SPACE;
 485                 fprintf(stderr, "leaf free space incorrect %llu %d\n",
 486                         (unsigned long long)btrfs_header_bytenr(buf),
 487                         btrfs_leaf_free_space(root->fs_info, buf));
 488                 goto fail;
 489         }
 490
 491         if (nritems == 0)
 492                 return BTRFS_TREE_BLOCK_CLEAN;
 493
 494         btrfs_item_key(buf, &key, 0);
 495         if (parent_key && parent_key->type &&
 496             memcmp(parent_key, &key, sizeof(key))) {
 497                 ret = BTRFS_TREE_BLOCK_INVALID_PARENT_KEY;
 498                 fprintf(stderr, "leaf parent key incorrect %llu\n",
 499                        (unsigned long long)btrfs_header_bytenr(buf));
 500                 goto fail;
 501         }
 502         for (i = 0; nritems > 1 && i < nritems - 1; i++) {
 503                 btrfs_item_key(buf, &key, i);
 504                 btrfs_item_key_to_cpu(buf, &cpukey, i + 1);
 505                 if (btrfs_comp_keys(&key, &cpukey) >= 0) {
 506                         ret = BTRFS_TREE_BLOCK_BAD_KEY_ORDER;
 507                         fprintf(stderr, "bad key ordering %d %d\n", i, i+1);
 508                         goto fail;
 509                 }
 510                 if (btrfs_item_offset_nr(buf, i) !=
 511                         btrfs_item_end_nr(buf, i + 1)) {
 512                         ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
 513                         fprintf(stderr, "incorrect offsets %u %u\n",
 514                                 btrfs_item_offset_nr(buf, i),
 515                                 btrfs_item_end_nr(buf, i + 1));
 516                         goto fail;
 517                 }
 518                 if (i == 0 && btrfs_item_end_nr(buf, i) !=
 519                     BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
 520                         ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
 521                         fprintf(stderr, "bad item end %u wanted %u\n",
 522                                 btrfs_item_end_nr(buf, i),
 523                                 (unsigned)BTRFS_LEAF_DATA_SIZE(root->fs_info));
 524                         goto fail;
 525                 }
 526         }
 527
 528         for (i = 0; i < nritems; i++) {
 529                 if (btrfs_item_end_nr(buf, i) >
 530                                 BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
 531                         btrfs_item_key(buf, &key, 0);
 532                         btrfs_print_key(&key);
 533                         fflush(stdout);
 534                         ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
 535                         fprintf(stderr, "slot end outside of leaf %llu > %llu\n",
 536                                 (unsigned long long)btrfs_item_end_nr(buf, i),
 537                                 (unsigned long long)BTRFS_LEAF_DATA_SIZE(
 538                                         root->fs_info));
 539                         goto fail;
 540                 }
 541         }
 542
 543         return BTRFS_TREE_BLOCK_CLEAN;
 544 fail:
 545         if (btrfs_header_owner(buf) == BTRFS_EXTENT_TREE_OBJECTID) {
 546                 if (parent_key)
 547                         btrfs_disk_key_to_cpu(&cpukey, parent_key);
 548                 else
 549                         btrfs_item_key_to_cpu(buf, &cpukey, 0);
 550
 551                 btrfs_add_corrupt_extent_record(root->fs_info, &cpukey,
 552                                                 buf->start, buf->len, 0);
 553         }
 554         return ret;
 555 }
 556
 557 static int noinline check_block(struct btrfs_root *root,
 558                                 struct btrfs_path *path, int level)
 559 {
 560         struct btrfs_disk_key key;
 561         struct btrfs_disk_key *key_ptr = NULL;
 562         struct extent_buffer *parent;
 563         enum btrfs_tree_block_status ret;
 564
 565         if (path->skip_check_block)
 566                 return 0;
 567         if (path->nodes[level + 1]) {
 568                 parent = path->nodes[level + 1];
 569                 btrfs_node_key(parent, &key, path->slots[level + 1]);
 570                 key_ptr = &key;
 571         }
 572         if (level == 0)
 573                 ret =  btrfs_check_leaf(root, key_ptr, path->nodes[0]);
 574         else
 575                 ret = btrfs_check_node(root, key_ptr, path->nodes[level]);
 576         if (ret == BTRFS_TREE_BLOCK_CLEAN)
 577                 return 0;
 578         return -EIO;
 579 }
 580
 581 /*
 582  * search for key in the extent_buffer.  The items start at offset p,
 583  * and they are item_size apart.  There are 'max' items in p.
 584  *
 585  * the slot in the array is returned via slot, and it points to
 586  * the place where you would insert key if it is not found in
 587  * the array.
 588  *
 589  * slot may point to max if the key is bigger than all of the keys
 590  */
 591 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
 592                               int item_size, struct btrfs_key *key,
 593                               int max, int *slot)
 594 {
 595         int low = 0;
 596         int high = max;
 597         int mid;
 598         int ret;
 599         unsigned long offset;
 600         struct btrfs_disk_key *tmp;
 601
 602         while(low < high) {
 603                 mid = (low + high) / 2;
 604                 offset = p + mid * item_size;
 605
 606                 tmp = (struct btrfs_disk_key *)(eb->data + offset);
 607                 ret = btrfs_comp_keys(tmp, key);
 608
 609                 if (ret < 0)
 610                         low = mid + 1;
 611                 else if (ret > 0)
 612                         high = mid;
 613                 else {
 614                         *slot = mid;
 615                         return 0;
 616                 }
 617         }
 618         *slot = low;
 619         return 1;
 620 }
 621
 622 /*
 623  * simple bin_search frontend that does the right thing for
 624  * leaves vs nodes
 625  */
 626 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
 627                       int level, int *slot)
 628 {
 629         if (level == 0)
 630                 return generic_bin_search(eb,
 631                                           offsetof(struct btrfs_leaf, items),
 632                                           sizeof(struct btrfs_item),
 633                                           key, btrfs_header_nritems(eb),
 634                                           slot);
 635         else
 636                 return generic_bin_search(eb,
 637                                           offsetof(struct btrfs_node, ptrs),
 638                                           sizeof(struct btrfs_key_ptr),
 639                                           key, btrfs_header_nritems(eb),
 640                                           slot);
 641 }
 642
 643 struct extent_buffer *read_node_slot(struct btrfs_fs_info *fs_info,
 644                                    struct extent_buffer *parent, int slot)
 645 {
 646         struct extent_buffer *ret;
 647         int level = btrfs_header_level(parent);
 648
 649         if (slot < 0)
 650                 return NULL;
 651         if (slot >= btrfs_header_nritems(parent))
 652                 return NULL;
 653
 654         if (level == 0)
 655                 return NULL;
 656
 657         ret = read_tree_block(fs_info, btrfs_node_blockptr(parent, slot),
 658                        btrfs_node_ptr_generation(parent, slot));
 659         if (!extent_buffer_uptodate(ret))
 660                 return ERR_PTR(-EIO);
 661
 662         if (btrfs_header_level(ret) != level - 1) {
 663                 error(
 664 "child eb corrupted: parent bytenr=%llu item=%d parent level=%d child level=%d",
 665                       btrfs_header_bytenr(parent), slot,
 666                       btrfs_header_level(parent), btrfs_header_level(ret));
 667                 free_extent_buffer(ret);
 668                 return ERR_PTR(-EIO);
 669         }
 670         return ret;
 671 }
 672
 673 static int balance_level(struct btrfs_trans_handle *trans,
 674                          struct btrfs_root *root,
 675                          struct btrfs_path *path, int level)
 676 {
 677         struct extent_buffer *right = NULL;
 678         struct extent_buffer *mid;
 679         struct extent_buffer *left = NULL;
 680         struct extent_buffer *parent = NULL;
 681         struct btrfs_fs_info *fs_info = root->fs_info;
 682         int ret = 0;
 683         int wret;
 684         int pslot;
 685         int orig_slot = path->slots[level];
 686         u64 orig_ptr;
 687
 688         if (level == 0)
 689                 return 0;
 690
 691         mid = path->nodes[level];
 692         WARN_ON(btrfs_header_generation(mid) != trans->transid);
 693
 694         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 695
 696         if (level < BTRFS_MAX_LEVEL - 1) {
 697                 parent = path->nodes[level + 1];
 698                 pslot = path->slots[level + 1];
 699         }
 700
 701         /*
 702          * deal with the case where there is only one pointer in the root
 703          * by promoting the node below to a root
 704          */
 705         if (!parent) {
 706                 struct extent_buffer *child;
 707
 708                 if (btrfs_header_nritems(mid) != 1)
 709                         return 0;
 710
 711                 /* promote the child to a root */
 712                 child = read_node_slot(fs_info, mid, 0);
 713                 BUG_ON(!extent_buffer_uptodate(child));
 714                 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
 715                 BUG_ON(ret);
 716
 717                 root->node = child;
 718                 add_root_to_dirty_list(root);
 719                 path->nodes[level] = NULL;
 720                 clean_tree_block(trans, root, mid);
 721                 /* once for the path */
 722                 free_extent_buffer(mid);
 723
 724                 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
 725                                         0, root->root_key.objectid,
 726                                         level, 1);
 727                 /* once for the root ptr */
 728                 free_extent_buffer(mid);
 729                 return ret;
 730         }
 731         if (btrfs_header_nritems(mid) >
 732             BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 4)
 733                 return 0;
 734
 735         left = read_node_slot(fs_info, parent, pslot - 1);
 736         if (extent_buffer_uptodate(left)) {
 737                 wret = btrfs_cow_block(trans, root, left,
 738                                        parent, pslot - 1, &left);
 739                 if (wret) {
 740                         ret = wret;
 741                         goto enospc;
 742                 }
 743         }
 744         right = read_node_slot(fs_info, parent, pslot + 1);
 745         if (extent_buffer_uptodate(right)) {
 746                 wret = btrfs_cow_block(trans, root, right,
 747                                        parent, pslot + 1, &right);
 748                 if (wret) {
 749                         ret = wret;
 750                         goto enospc;
 751                 }
 752         }
 753
 754         /* first, try to make some room in the middle buffer */
 755         if (left) {
 756                 orig_slot += btrfs_header_nritems(left);
 757                 wret = push_node_left(trans, root, left, mid, 1);
 758                 if (wret < 0)
 759                         ret = wret;
 760         }
 761
 762         /*
 763          * then try to empty the right most buffer into the middle
 764          */
 765         if (right) {
 766                 wret = push_node_left(trans, root, mid, right, 1);
 767                 if (wret < 0 && wret != -ENOSPC)
 768                         ret = wret;
 769                 if (btrfs_header_nritems(right) == 0) {
 770                         u64 bytenr = right->start;
 771                         u32 blocksize = right->len;
 772
 773                         clean_tree_block(trans, root, right);
 774                         free_extent_buffer(right);
 775                         right = NULL;
 776                         wret = btrfs_del_ptr(root, path, level + 1, pslot + 1);
 777                         if (wret)
 778                                 ret = wret;
 779                         wret = btrfs_free_extent(trans, root, bytenr,
 780                                                  blocksize, 0,
 781                                                  root->root_key.objectid,
 782                                                  level, 0);
 783                         if (wret)
 784                                 ret = wret;
 785                 } else {
 786                         struct btrfs_disk_key right_key;
 787                         btrfs_node_key(right, &right_key, 0);
 788                         btrfs_set_node_key(parent, &right_key, pslot + 1);
 789                         btrfs_mark_buffer_dirty(parent);
 790                 }
 791         }
 792         if (btrfs_header_nritems(mid) == 1) {
 793                 /*
 794                  * we're not allowed to leave a node with one item in the
 795                  * tree during a delete.  A deletion from lower in the tree
 796                  * could try to delete the only pointer in this node.
 797                  * So, pull some keys from the left.
 798                  * There has to be a left pointer at this point because
 799                  * otherwise we would have pulled some pointers from the
 800                  * right
 801                  */
 802                 BUG_ON(!left);
 803                 wret = balance_node_right(trans, root, mid, left);
 804                 if (wret < 0) {
 805                         ret = wret;
 806                         goto enospc;
 807                 }
 808                 if (wret == 1) {
 809                         wret = push_node_left(trans, root, left, mid, 1);
 810                         if (wret < 0)
 811                                 ret = wret;
 812                 }
 813                 BUG_ON(wret == 1);
 814         }
 815         if (btrfs_header_nritems(mid) == 0) {
 816                 /* we've managed to empty the middle node, drop it */
 817                 u64 bytenr = mid->start;
 818                 u32 blocksize = mid->len;
 819                 clean_tree_block(trans, root, mid);
 820                 free_extent_buffer(mid);
 821                 mid = NULL;
 822                 wret = btrfs_del_ptr(root, path, level + 1, pslot);
 823                 if (wret)
 824                         ret = wret;
 825                 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
 826                                          0, root->root_key.objectid,
 827                                          level, 0);
 828                 if (wret)
 829                         ret = wret;
 830         } else {
 831                 /* update the parent key to reflect our changes */
 832                 struct btrfs_disk_key mid_key;
 833                 btrfs_node_key(mid, &mid_key, 0);
 834                 btrfs_set_node_key(parent, &mid_key, pslot);
 835                 btrfs_mark_buffer_dirty(parent);
 836         }
 837
 838         /* update the path */
 839         if (left) {
 840                 if (btrfs_header_nritems(left) > orig_slot) {
 841                         extent_buffer_get(left);
 842                         path->nodes[level] = left;
 843                         path->slots[level + 1] -= 1;
 844                         path->slots[level] = orig_slot;
 845                         if (mid)
 846                                 free_extent_buffer(mid);
 847                 } else {
 848                         orig_slot -= btrfs_header_nritems(left);
 849                         path->slots[level] = orig_slot;
 850                 }
 851         }
 852         /* double check we haven't messed things up */
 853         check_block(root, path, level);
 854         if (orig_ptr !=
 855             btrfs_node_blockptr(path->nodes[level], path->slots[level]))
 856                 BUG();
 857 enospc:
 858         if (right)
 859                 free_extent_buffer(right);
 860         if (left)
 861                 free_extent_buffer(left);
 862         return ret;
 863 }
 864
 865 /* returns zero if the push worked, non-zero otherwise */
 866 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
 867                                           struct btrfs_root *root,
 868                                           struct btrfs_path *path, int level)
 869 {
 870         struct extent_buffer *right = NULL;
 871         struct extent_buffer *mid;
 872         struct extent_buffer *left = NULL;
 873         struct extent_buffer *parent = NULL;
 874         struct btrfs_fs_info *fs_info = root->fs_info;
 875         int ret = 0;
 876         int wret;
 877         int pslot;
 878         int orig_slot = path->slots[level];
 879
 880         if (level == 0)
 881                 return 1;
 882
 883         mid = path->nodes[level];
 884         WARN_ON(btrfs_header_generation(mid) != trans->transid);
 885
 886         if (level < BTRFS_MAX_LEVEL - 1) {
 887                 parent = path->nodes[level + 1];
 888                 pslot = path->slots[level + 1];
 889         }
 890
 891         if (!parent)
 892                 return 1;
 893
 894         left = read_node_slot(fs_info, parent, pslot - 1);
 895
 896         /* first, try to make some room in the middle buffer */
 897         if (extent_buffer_uptodate(left)) {
 898                 u32 left_nr;
 899                 left_nr = btrfs_header_nritems(left);
 900                 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) {
 901                         wret = 1;
 902                 } else {
 903                         ret = btrfs_cow_block(trans, root, left, parent,
 904                                               pslot - 1, &left);
 905                         if (ret)
 906                                 wret = 1;
 907                         else {
 908                                 wret = push_node_left(trans, root,
 909                                                       left, mid, 0);
 910                         }
 911                 }
 912                 if (wret < 0)
 913                         ret = wret;
 914                 if (wret == 0) {
 915                         struct btrfs_disk_key disk_key;
 916                         orig_slot += left_nr;
 917                         btrfs_node_key(mid, &disk_key, 0);
 918                         btrfs_set_node_key(parent, &disk_key, pslot);
 919                         btrfs_mark_buffer_dirty(parent);
 920                         if (btrfs_header_nritems(left) > orig_slot) {
 921                                 path->nodes[level] = left;
 922                                 path->slots[level + 1] -= 1;
 923                                 path->slots[level] = orig_slot;
 924                                 free_extent_buffer(mid);
 925                         } else {
 926                                 orig_slot -=
 927                                         btrfs_header_nritems(left);
 928                                 path->slots[level] = orig_slot;
 929                                 free_extent_buffer(left);
 930                         }
 931                         return 0;
 932                 }
 933                 free_extent_buffer(left);
 934         }
 935         right= read_node_slot(fs_info, parent, pslot + 1);
 936
 937         /*
 938          * then try to empty the right most buffer into the middle
 939          */
 940         if (extent_buffer_uptodate(right)) {
 941                 u32 right_nr;
 942                 right_nr = btrfs_header_nritems(right);
 943                 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root->fs_info) - 1) {
 944                         wret = 1;
 945                 } else {
 946                         ret = btrfs_cow_block(trans, root, right,
 947                                               parent, pslot + 1,
 948                                               &right);
 949                         if (ret)
 950                                 wret = 1;
 951                         else {
 952                                 wret = balance_node_right(trans, root,
 953                                                           right, mid);
 954                         }
 955                 }
 956                 if (wret < 0)
 957                         ret = wret;
 958                 if (wret == 0) {
 959                         struct btrfs_disk_key disk_key;
 960
 961                         btrfs_node_key(right, &disk_key, 0);
 962                         btrfs_set_node_key(parent, &disk_key, pslot + 1);
 963                         btrfs_mark_buffer_dirty(parent);
 964
 965                         if (btrfs_header_nritems(mid) <= orig_slot) {
 966                                 path->nodes[level] = right;
 967                                 path->slots[level + 1] += 1;
 968                                 path->slots[level] = orig_slot -
 969                                         btrfs_header_nritems(mid);
 970                                 free_extent_buffer(mid);
 971                         } else {
 972                                 free_extent_buffer(right);
 973                         }
 974                         return 0;
 975                 }
 976                 free_extent_buffer(right);
 977         }
 978         return 1;
 979 }
 980
 981 /*
 982  * readahead one full node of leaves
 983  */
 984 void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
 985                              int level, int slot, u64 objectid)
 986 {
 987         struct btrfs_fs_info *fs_info = root->fs_info;
 988         struct extent_buffer *node;
 989         struct btrfs_disk_key disk_key;
 990         u32 nritems;
 991         u64 search;
 992         u64 lowest_read;
 993         u64 highest_read;
 994         u64 nread = 0;
 995         int direction = path->reada;
 996         struct extent_buffer *eb;
 997         u32 nr;
 998         u32 nscan = 0;
 999
1000         if (level != 1)
1001                 return;
1002
1003         if (!path->nodes[level])
1004                 return;
1005
1006         node = path->nodes[level];
1007         search = btrfs_node_blockptr(node, slot);
1008         eb = btrfs_find_tree_block(fs_info, search, fs_info->nodesize);
1009         if (eb) {
1010                 free_extent_buffer(eb);
1011                 return;
1012         }
1013
1014         highest_read = search;
1015         lowest_read = search;
1016
1017         nritems = btrfs_header_nritems(node);
1018         nr = slot;
1019         while(1) {
1020                 if (direction < 0) {
1021                         if (nr == 0)
1022                                 break;
1023                         nr--;
1024                 } else if (direction > 0) {
1025                         nr++;
1026                         if (nr >= nritems)
1027                                 break;
1028                 }
1029                 if (path->reada < 0 && objectid) {
1030                         btrfs_node_key(node, &disk_key, nr);
1031                         if (btrfs_disk_key_objectid(&disk_key) != objectid)
1032                                 break;
1033                 }
1034                 search = btrfs_node_blockptr(node, nr);
1035                 if ((search >= lowest_read && search <= highest_read) ||
1036                     (search < lowest_read && lowest_read - search <= 32768) ||
1037                     (search > highest_read && search - highest_read <= 32768)) {
1038                         readahead_tree_block(fs_info, search,
1039                                      btrfs_node_ptr_generation(node, nr));
1040                         nread += fs_info->nodesize;
1041                 }
1042                 nscan++;
1043                 if (path->reada < 2 && (nread > SZ_256K || nscan > 32))
1044                         break;
1045                 if(nread > SZ_1M || nscan > 128)
1046                         break;
1047
1048                 if (search < lowest_read)
1049                         lowest_read = search;
1050                 if (search > highest_read)
1051                         highest_read = search;
1052         }
1053 }
1054
1055 int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *found_path,
1056                 u64 iobjectid, u64 ioff, u8 key_type,
1057                 struct btrfs_key *found_key)
1058 {
1059         int ret;
1060         struct btrfs_key key;
1061         struct extent_buffer *eb;
1062         struct btrfs_path *path;
1063
1064         key.type = key_type;
1065         key.objectid = iobjectid;
1066         key.offset = ioff;
1067
1068         if (found_path == NULL) {
1069                 path = btrfs_alloc_path();
1070                 if (!path)
1071                         return -ENOMEM;
1072         } else
1073                 path = found_path;
1074
1075         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1076         if ((ret < 0) || (found_key == NULL))
1077                 goto out;
1078
1079         eb = path->nodes[0];
1080         if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
1081                 ret = btrfs_next_leaf(fs_root, path);
1082                 if (ret)
1083                         goto out;
1084                 eb = path->nodes[0];
1085         }
1086
1087         btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
1088         if (found_key->type != key.type ||
1089                         found_key->objectid != key.objectid) {
1090                 ret = 1;
1091                 goto out;
1092         }
1093
1094 out:
1095         if (path != found_path)
1096                 btrfs_free_path(path);
1097         return ret;
1098 }
1099
1100 /*
1101  * look for key in the tree.  path is filled in with nodes along the way
1102  * if key is found, we return zero and you can find the item in the leaf
1103  * level of the path (level 0)
1104  *
1105  * If the key isn't found, the path points to the slot where it should
1106  * be inserted, and 1 is returned.  If there are other errors during the
1107  * search a negative error number is returned.
1108  *
1109  * if ins_len > 0, nodes and leaves will be split as we walk down the
1110  * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
1111  * possible)
1112  */
1113 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1114                       *root, struct btrfs_key *key, struct btrfs_path *p, int
1115                       ins_len, int cow)
1116 {
1117         struct extent_buffer *b;
1118         int slot;
1119         int ret;
1120         int level;
1121         int should_reada = p->reada;
1122         struct btrfs_fs_info *fs_info = root->fs_info;
1123         u8 lowest_level = 0;
1124
1125         lowest_level = p->lowest_level;
1126         WARN_ON(lowest_level && ins_len > 0);
1127         WARN_ON(p->nodes[0] != NULL);
1128         /*
1129         WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1130         */
1131 again:
1132         b = root->node;
1133         extent_buffer_get(b);
1134         while (b) {
1135                 level = btrfs_header_level(b);
1136                 if (cow) {
1137                         int wret;
1138                         wret = btrfs_cow_block(trans, root, b,
1139                                                p->nodes[level + 1],
1140                                                p->slots[level + 1],
1141                                                &b);
1142                         if (wret) {
1143                                 free_extent_buffer(b);
1144                                 return wret;
1145                         }
1146                 }
1147                 BUG_ON(!cow && ins_len);
1148                 if (level != btrfs_header_level(b))
1149                         WARN_ON(1);
1150                 level = btrfs_header_level(b);
1151                 p->nodes[level] = b;
1152                 ret = check_block(root, p, level);
1153                 if (ret)
1154                         return -1;
1155                 ret = bin_search(b, key, level, &slot);
1156                 if (level != 0) {
1157                         if (ret && slot > 0)
1158                                 slot -= 1;
1159                         p->slots[level] = slot;
1160                         if ((p->search_for_split || ins_len > 0) &&
1161                             btrfs_header_nritems(b) >=
1162                             BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) {
1163                                 int sret = split_node(trans, root, p, level);
1164                                 BUG_ON(sret > 0);
1165                                 if (sret)
1166                                         return sret;
1167                                 b = p->nodes[level];
1168                                 slot = p->slots[level];
1169                         } else if (ins_len < 0) {
1170                                 int sret = balance_level(trans, root, p,
1171                                                          level);
1172                                 if (sret)
1173                                         return sret;
1174                                 b = p->nodes[level];
1175                                 if (!b) {
1176                                         btrfs_release_path(p);
1177                                         goto again;
1178                                 }
1179                                 slot = p->slots[level];
1180                                 BUG_ON(btrfs_header_nritems(b) == 1);
1181                         }
1182                         /* this is only true while dropping a snapshot */
1183                         if (level == lowest_level)
1184                                 break;
1185
1186                         if (should_reada)
1187                                 reada_for_search(root, p, level, slot,
1188                                                  key->objectid);
1189
1190                         b = read_node_slot(fs_info, b, slot);
1191                         if (!extent_buffer_uptodate(b))
1192                                 return -EIO;
1193                 } else {
1194                         p->slots[level] = slot;
1195                         if (ins_len > 0 &&
1196                             ins_len > btrfs_leaf_free_space(root->fs_info, b)) {
1197                                 int sret = split_leaf(trans, root, key,
1198                                                       p, ins_len, ret == 0);
1199                                 BUG_ON(sret > 0);
1200                                 if (sret)
1201                                         return sret;
1202                         }
1203                         return ret;
1204                 }
1205         }
1206         return 1;
1207 }
1208
1209 /*
1210  * adjust the pointers going up the tree, starting at level
1211  * making sure the right key of each node is points to 'key'.
1212  * This is used after shifting pointers to the left, so it stops
1213  * fixing up pointers when a given leaf/node is not in slot 0 of the
1214  * higher levels
1215  */
1216 void btrfs_fixup_low_keys(struct btrfs_root *root, struct btrfs_path *path,
1217                           struct btrfs_disk_key *key, int level)
1218 {
1219         int i;
1220         struct extent_buffer *t;
1221
1222         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1223                 int tslot = path->slots[i];
1224                 if (!path->nodes[i])
1225                         break;
1226                 t = path->nodes[i];
1227                 btrfs_set_node_key(t, key, tslot);
1228                 btrfs_mark_buffer_dirty(path->nodes[i]);
1229                 if (tslot != 0)
1230                         break;
1231         }
1232 }
1233
1234 /*
1235  * update item key.
1236  *
1237  * This function isn't completely safe. It's the caller's responsibility
1238  * that the new key won't break the order
1239  */
1240 int btrfs_set_item_key_safe(struct btrfs_root *root, struct btrfs_path *path,
1241                             struct btrfs_key *new_key)
1242 {
1243         struct btrfs_disk_key disk_key;
1244         struct extent_buffer *eb;
1245         int slot;
1246
1247         eb = path->nodes[0];
1248         slot = path->slots[0];
1249         if (slot > 0) {
1250                 btrfs_item_key(eb, &disk_key, slot - 1);
1251                 if (btrfs_comp_keys(&disk_key, new_key) >= 0)
1252                         return -1;
1253         }
1254         if (slot < btrfs_header_nritems(eb) - 1) {
1255                 btrfs_item_key(eb, &disk_key, slot + 1);
1256                 if (btrfs_comp_keys(&disk_key, new_key) <= 0)
1257                         return -1;
1258         }
1259
1260         btrfs_cpu_key_to_disk(&disk_key, new_key);
1261         btrfs_set_item_key(eb, &disk_key, slot);
1262         btrfs_mark_buffer_dirty(eb);
1263         if (slot == 0)
1264                 btrfs_fixup_low_keys(root, path, &disk_key, 1);
1265         return 0;
1266 }
1267
1268 /*
1269  * update an item key without the safety checks.  This is meant to be called by
1270  * fsck only.
1271  */
1272 void btrfs_set_item_key_unsafe(struct btrfs_root *root,
1273                                struct btrfs_path *path,
1274                                struct btrfs_key *new_key)
1275 {
1276         struct btrfs_disk_key disk_key;
1277         struct extent_buffer *eb;
1278         int slot;
1279
1280         eb = path->nodes[0];
1281         slot = path->slots[0];
1282
1283         btrfs_cpu_key_to_disk(&disk_key, new_key);
1284         btrfs_set_item_key(eb, &disk_key, slot);
1285         btrfs_mark_buffer_dirty(eb);
1286         if (slot == 0)
1287                 btrfs_fixup_low_keys(root, path, &disk_key, 1);
1288 }
1289
1290 /*
1291  * try to push data from one node into the next node left in the
1292  * tree.
1293  *
1294  * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1295  * error, and > 0 if there was no room in the left hand block.
1296  */
1297 static int push_node_left(struct btrfs_trans_handle *trans,
1298                           struct btrfs_root *root, struct extent_buffer *dst,
1299                           struct extent_buffer *src, int empty)
1300 {
1301         int push_items = 0;
1302         int src_nritems;
1303         int dst_nritems;
1304         int ret = 0;
1305
1306         src_nritems = btrfs_header_nritems(src);
1307         dst_nritems = btrfs_header_nritems(dst);
1308         push_items = BTRFS_NODEPTRS_PER_BLOCK(root->fs_info) - dst_nritems;
1309         WARN_ON(btrfs_header_generation(src) != trans->transid);
1310         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1311
1312         if (!empty && src_nritems <= 8)
1313                 return 1;
1314
1315         if (push_items <= 0) {
1316                 return 1;
1317         }
1318
1319         if (empty) {
1320                 push_items = min(src_nritems, push_items);
1321                 if (push_items < src_nritems) {
1322                         /* leave at least 8 pointers in the node if
1323                          * we aren't going to empty it
1324                          */
1325                         if (src_nritems - push_items < 8) {
1326                                 if (push_items <= 8)
1327                                         return 1;
1328                                 push_items -= 8;
1329                         }
1330                 }
1331         } else
1332                 push_items = min(src_nritems - 8, push_items);
1333
1334         copy_extent_buffer(dst, src,
1335                            btrfs_node_key_ptr_offset(dst_nritems),
1336                            btrfs_node_key_ptr_offset(0),
1337                            push_items * sizeof(struct btrfs_key_ptr));
1338
1339         if (push_items < src_nritems) {
1340                 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1341                                       btrfs_node_key_ptr_offset(push_items),
1342                                       (src_nritems - push_items) *
1343                                       sizeof(struct btrfs_key_ptr));
1344         }
1345         btrfs_set_header_nritems(src, src_nritems - push_items);
1346         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1347         btrfs_mark_buffer_dirty(src);
1348         btrfs_mark_buffer_dirty(dst);
1349
1350         return ret;
1351 }
1352
1353 /*
1354  * try to push data from one node into the next node right in the
1355  * tree.
1356  *
1357  * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1358  * error, and > 0 if there was no room in the right hand block.
1359  *
1360  * this will  only push up to 1/2 the contents of the left node over
1361  */
1362 static int balance_node_right(struct btrfs_trans_handle *trans,
1363                               struct btrfs_root *root,
1364                               struct extent_buffer *dst,
1365                               struct extent_buffer *src)
1366 {
1367         int push_items = 0;
1368         int max_push;
1369         int src_nritems;
1370         int dst_nritems;
1371         int ret = 0;
1372
1373         WARN_ON(btrfs_header_generation(src) != trans->transid);
1374         WARN_ON(btrfs_header_generation(dst) != trans->transid);
1375
1376         src_nritems = btrfs_header_nritems(src);
1377         dst_nritems = btrfs_header_nritems(dst);
1378         push_items = BTRFS_NODEPTRS_PER_BLOCK(root->fs_info) - dst_nritems;
1379         if (push_items <= 0) {
1380                 return 1;
1381         }
1382
1383         if (src_nritems < 4) {
1384                 return 1;
1385         }
1386
1387         max_push = src_nritems / 2 + 1;
1388         /* don't try to empty the node */
1389         if (max_push >= src_nritems) {
1390                 return 1;
1391         }
1392
1393         if (max_push < push_items)
1394                 push_items = max_push;
1395
1396         memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1397                                       btrfs_node_key_ptr_offset(0),
1398                                       (dst_nritems) *
1399                                       sizeof(struct btrfs_key_ptr));
1400
1401         copy_extent_buffer(dst, src,
1402                            btrfs_node_key_ptr_offset(0),
1403                            btrfs_node_key_ptr_offset(src_nritems - push_items),
1404                            push_items * sizeof(struct btrfs_key_ptr));
1405
1406         btrfs_set_header_nritems(src, src_nritems - push_items);
1407         btrfs_set_header_nritems(dst, dst_nritems + push_items);
1408
1409         btrfs_mark_buffer_dirty(src);
1410         btrfs_mark_buffer_dirty(dst);
1411
1412         return ret;
1413 }
1414
1415 /*
1416  * helper function to insert a new root level in the tree.
1417  * A new node is allocated, and a single item is inserted to
1418  * point to the existing root
1419  *
1420  * returns zero on success or < 0 on failure.
1421  */
1422 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1423                            struct btrfs_root *root,
1424                            struct btrfs_path *path, int level)
1425 {
1426         u64 lower_gen;
1427         struct extent_buffer *lower;
1428         struct extent_buffer *c;
1429         struct extent_buffer *old;
1430         struct btrfs_disk_key lower_key;
1431
1432         BUG_ON(path->nodes[level]);
1433         BUG_ON(path->nodes[level-1] != root->node);
1434
1435         lower = path->nodes[level-1];
1436         if (level == 1)
1437                 btrfs_item_key(lower, &lower_key, 0);
1438         else
1439                 btrfs_node_key(lower, &lower_key, 0);
1440
1441         c = btrfs_alloc_free_block(trans, root, root->fs_info->nodesize,
1442                                    root->root_key.objectid, &lower_key,
1443                                    level, root->node->start, 0);
1444
1445         if (IS_ERR(c))
1446                 return PTR_ERR(c);
1447
1448         memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header));
1449         btrfs_set_header_nritems(c, 1);
1450         btrfs_set_header_level(c, level);
1451         btrfs_set_header_bytenr(c, c->start);
1452         btrfs_set_header_generation(c, trans->transid);
1453         btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV);
1454         btrfs_set_header_owner(c, root->root_key.objectid);
1455
1456         write_extent_buffer(c, root->fs_info->fsid,
1457                             btrfs_header_fsid(), BTRFS_FSID_SIZE);
1458
1459         write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1460                             btrfs_header_chunk_tree_uuid(c),
1461                             BTRFS_UUID_SIZE);
1462
1463         btrfs_set_node_key(c, &lower_key, 0);
1464         btrfs_set_node_blockptr(c, 0, lower->start);
1465         lower_gen = btrfs_header_generation(lower);
1466         WARN_ON(lower_gen != trans->transid);
1467
1468         btrfs_set_node_ptr_generation(c, 0, lower_gen);
1469
1470         btrfs_mark_buffer_dirty(c);
1471
1472         old = root->node;
1473         root->node = c;
1474
1475         /* the super has an extra ref to root->node */
1476         free_extent_buffer(old);
1477
1478         add_root_to_dirty_list(root);
1479         extent_buffer_get(c);
1480         path->nodes[level] = c;
1481         path->slots[level] = 0;
1482         return 0;
1483 }
1484
1485 /*
1486  * worker function to insert a single pointer in a node.
1487  * the node should have enough room for the pointer already
1488  *
1489  * slot and level indicate where you want the key to go, and
1490  * blocknr is the block the key points to.
1491  *
1492  * returns zero on success and < 0 on any error
1493  */
1494 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1495                       *root, struct btrfs_path *path, struct btrfs_disk_key
1496                       *key, u64 bytenr, int slot, int level)
1497 {
1498         struct extent_buffer *lower;
1499         int nritems;
1500
1501         BUG_ON(!path->nodes[level]);
1502         lower = path->nodes[level];
1503         nritems = btrfs_header_nritems(lower);
1504         if (slot > nritems)
1505                 BUG();
1506         if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root->fs_info))
1507                 BUG();
1508         if (slot < nritems) {
1509                 /* shift the items */
1510                 memmove_extent_buffer(lower,
1511                               btrfs_node_key_ptr_offset(slot + 1),
1512                               btrfs_node_key_ptr_offset(slot),
1513                               (nritems - slot) * sizeof(struct btrfs_key_ptr));
1514         }
1515         btrfs_set_node_key(lower, key, slot);
1516         btrfs_set_node_blockptr(lower, slot, bytenr);
1517         WARN_ON(trans->transid == 0);
1518         btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1519         btrfs_set_header_nritems(lower, nritems + 1);
1520         btrfs_mark_buffer_dirty(lower);
1521         return 0;
1522 }
1523
1524 /*
1525  * split the node at the specified level in path in two.
1526  * The path is corrected to point to the appropriate node after the split
1527  *
1528  * Before splitting this tries to make some room in the node by pushing
1529  * left and right, if either one works, it returns right away.
1530  *
1531  * returns 0 on success and < 0 on failure
1532  */
1533 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1534                       *root, struct btrfs_path *path, int level)
1535 {
1536         struct extent_buffer *c;
1537         struct extent_buffer *split;
1538         struct btrfs_disk_key disk_key;
1539         int mid;
1540         int ret;
1541         int wret;
1542         u32 c_nritems;
1543
1544         c = path->nodes[level];
1545         WARN_ON(btrfs_header_generation(c) != trans->transid);
1546         if (c == root->node) {
1547                 /* trying to split the root, lets make a new one */
1548                 ret = insert_new_root(trans, root, path, level + 1);
1549                 if (ret)
1550                         return ret;
1551         } else {
1552                 ret = push_nodes_for_insert(trans, root, path, level);
1553                 c = path->nodes[level];
1554                 if (!ret && btrfs_header_nritems(c) <
1555                     BTRFS_NODEPTRS_PER_BLOCK(root->fs_info) - 3)
1556                         return 0;
1557                 if (ret < 0)
1558                         return ret;
1559         }
1560
1561         c_nritems = btrfs_header_nritems(c);
1562         mid = (c_nritems + 1) / 2;
1563         btrfs_node_key(c, &disk_key, mid);
1564
1565         split = btrfs_alloc_free_block(trans, root, root->fs_info->nodesize,
1566                                         root->root_key.objectid,
1567                                         &disk_key, level, c->start, 0);
1568         if (IS_ERR(split))
1569                 return PTR_ERR(split);
1570
1571         memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header));
1572         btrfs_set_header_level(split, btrfs_header_level(c));
1573         btrfs_set_header_bytenr(split, split->start);
1574         btrfs_set_header_generation(split, trans->transid);
1575         btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV);
1576         btrfs_set_header_owner(split, root->root_key.objectid);
1577         write_extent_buffer(split, root->fs_info->fsid,
1578                             btrfs_header_fsid(), BTRFS_FSID_SIZE);
1579         write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1580                             btrfs_header_chunk_tree_uuid(split),
1581                             BTRFS_UUID_SIZE);
1582
1583
1584         copy_extent_buffer(split, c,
1585                            btrfs_node_key_ptr_offset(0),
1586                            btrfs_node_key_ptr_offset(mid),
1587                            (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1588         btrfs_set_header_nritems(split, c_nritems - mid);
1589         btrfs_set_header_nritems(c, mid);
1590         ret = 0;
1591
1592         btrfs_mark_buffer_dirty(c);
1593         btrfs_mark_buffer_dirty(split);
1594
1595         wret = insert_ptr(trans, root, path, &disk_key, split->start,
1596                           path->slots[level + 1] + 1,
1597                           level + 1);
1598         if (wret)
1599                 ret = wret;
1600
1601         if (path->slots[level] >= mid) {
1602                 path->slots[level] -= mid;
1603                 free_extent_buffer(c);
1604                 path->nodes[level] = split;
1605                 path->slots[level + 1] += 1;
1606         } else {
1607                 free_extent_buffer(split);
1608         }
1609         return ret;
1610 }
1611
1612 /*
1613  * how many bytes are required to store the items in a leaf.  start
1614  * and nr indicate which items in the leaf to check.  This totals up the
1615  * space used both by the item structs and the item data
1616  */
1617 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1618 {
1619         int data_len;
1620         int nritems = btrfs_header_nritems(l);
1621         int end = min(nritems, start + nr) - 1;
1622
1623         if (!nr)
1624                 return 0;
1625         data_len = btrfs_item_end_nr(l, start);
1626         data_len = data_len - btrfs_item_offset_nr(l, end);
1627         data_len += sizeof(struct btrfs_item) * nr;
1628         WARN_ON(data_len < 0);
1629         return data_len;
1630 }
1631
1632 /*
1633  * The space between the end of the leaf items and
1634  * the start of the leaf data.  IOW, how much room
1635  * the leaf has left for both items and data
1636  */
1637 int btrfs_leaf_free_space(struct btrfs_fs_info *fs_info,
1638                           struct extent_buffer *leaf)
1639 {
1640         int nritems = btrfs_header_nritems(leaf);
1641         int ret;
1642
1643         ret = BTRFS_LEAF_DATA_SIZE(fs_info) - leaf_space_used(leaf, 0, nritems);
1644         if (ret < 0) {
1645                 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1646                        ret, BTRFS_LEAF_DATA_SIZE(fs_info),
1647                        leaf_space_used(leaf, 0, nritems), nritems);
1648         }
1649         return ret;
1650 }
1651
1652 /*
1653  * push some data in the path leaf to the right, trying to free up at
1654  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1655  *
1656  * returns 1 if the push failed because the other node didn't have enough
1657  * room, 0 if everything worked out and < 0 if there were major errors.
1658  */
1659 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1660                            *root, struct btrfs_path *path, int data_size,
1661                            int empty)
1662 {
1663         struct extent_buffer *left = path->nodes[0];
1664         struct extent_buffer *right;
1665         struct extent_buffer *upper;
1666         struct btrfs_disk_key disk_key;
1667         struct btrfs_fs_info *fs_info = root->fs_info;
1668         int slot;
1669         u32 i;
1670         int free_space;
1671         int push_space = 0;
1672         int push_items = 0;
1673         struct btrfs_item *item;
1674         u32 left_nritems;
1675         u32 nr;
1676         u32 right_nritems;
1677         u32 data_end;
1678         u32 this_item_size;
1679         int ret;
1680
1681         slot = path->slots[1];
1682         if (!path->nodes[1]) {
1683                 return 1;
1684         }
1685         upper = path->nodes[1];
1686         if (slot >= btrfs_header_nritems(upper) - 1)
1687                 return 1;
1688
1689         right = read_node_slot(fs_info, upper, slot + 1);
1690         if (!extent_buffer_uptodate(right)) {
1691                 if (IS_ERR(right))
1692                         return PTR_ERR(right);
1693                 return -EIO;
1694         }
1695         free_space = btrfs_leaf_free_space(fs_info, right);
1696         if (free_space < data_size) {
1697                 free_extent_buffer(right);
1698                 return 1;
1699         }
1700
1701         /* cow and double check */
1702         ret = btrfs_cow_block(trans, root, right, upper,
1703                               slot + 1, &right);
1704         if (ret) {
1705                 free_extent_buffer(right);
1706                 return 1;
1707         }
1708         free_space = btrfs_leaf_free_space(fs_info, right);
1709         if (free_space < data_size) {
1710                 free_extent_buffer(right);
1711                 return 1;
1712         }
1713
1714         left_nritems = btrfs_header_nritems(left);
1715         if (left_nritems == 0) {
1716                 free_extent_buffer(right);
1717                 return 1;
1718         }
1719
1720         if (empty)
1721                 nr = 0;
1722         else
1723                 nr = 1;
1724
1725         i = left_nritems - 1;
1726         while (i >= nr) {
1727                 item = btrfs_item_nr(i);
1728
1729                 if (path->slots[0] == i)
1730                         push_space += data_size + sizeof(*item);
1731
1732                 this_item_size = btrfs_item_size(left, item);
1733                 if (this_item_size + sizeof(*item) + push_space > free_space)
1734                         break;
1735                 push_items++;
1736                 push_space += this_item_size + sizeof(*item);
1737                 if (i == 0)
1738                         break;
1739                 i--;
1740         }
1741
1742         if (push_items == 0) {
1743                 free_extent_buffer(right);
1744                 return 1;
1745         }
1746
1747         if (!empty && push_items == left_nritems)
1748                 WARN_ON(1);
1749
1750         /* push left to right */
1751         right_nritems = btrfs_header_nritems(right);
1752
1753         push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1754         push_space -= leaf_data_end(fs_info, left);
1755
1756         /* make room in the right data area */
1757         data_end = leaf_data_end(fs_info, right);
1758         memmove_extent_buffer(right,
1759                               btrfs_leaf_data(right) + data_end - push_space,
1760                               btrfs_leaf_data(right) + data_end,
1761                               BTRFS_LEAF_DATA_SIZE(root->fs_info) - data_end);
1762
1763         /* copy from the left data area */
1764         copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1765                      BTRFS_LEAF_DATA_SIZE(root->fs_info) - push_space,
1766                      btrfs_leaf_data(left) + leaf_data_end(fs_info, left),
1767                      push_space);
1768
1769         memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1770                               btrfs_item_nr_offset(0),
1771                               right_nritems * sizeof(struct btrfs_item));
1772
1773         /* copy the items from left to right */
1774         copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1775                    btrfs_item_nr_offset(left_nritems - push_items),
1776                    push_items * sizeof(struct btrfs_item));
1777
1778         /* update the item pointers */
1779         right_nritems += push_items;
1780         btrfs_set_header_nritems(right, right_nritems);
1781         push_space = BTRFS_LEAF_DATA_SIZE(root->fs_info);
1782         for (i = 0; i < right_nritems; i++) {
1783                 item = btrfs_item_nr(i);
1784                 push_space -= btrfs_item_size(right, item);
1785                 btrfs_set_item_offset(right, item, push_space);
1786         }
1787
1788         left_nritems -= push_items;
1789         btrfs_set_header_nritems(left, left_nritems);
1790
1791         if (left_nritems)
1792                 btrfs_mark_buffer_dirty(left);
1793         btrfs_mark_buffer_dirty(right);
1794
1795         btrfs_item_key(right, &disk_key, 0);
1796         btrfs_set_node_key(upper, &disk_key, slot + 1);
1797         btrfs_mark_buffer_dirty(upper);
1798
1799         /* then fixup the leaf pointer in the path */
1800         if (path->slots[0] >= left_nritems) {
1801                 path->slots[0] -= left_nritems;
1802                 free_extent_buffer(path->nodes[0]);
1803                 path->nodes[0] = right;
1804                 path->slots[1] += 1;
1805         } else {
1806                 free_extent_buffer(right);
1807         }
1808         return 0;
1809 }
1810 /*
1811  * push some data in the path leaf to the left, trying to free up at
1812  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1813  */
1814 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1815                           *root, struct btrfs_path *path, int data_size,
1816                           int empty)
1817 {
1818         struct btrfs_disk_key disk_key;
1819         struct extent_buffer *right = path->nodes[0];
1820         struct extent_buffer *left;
1821         struct btrfs_fs_info *fs_info = root->fs_info;
1822         int slot;
1823         int i;
1824         int free_space;
1825         int push_space = 0;
1826         int push_items = 0;
1827         struct btrfs_item *item;
1828         u32 old_left_nritems;
1829         u32 right_nritems;
1830         u32 nr;
1831         int ret = 0;
1832         u32 this_item_size;
1833         u32 old_left_item_size;
1834
1835         slot = path->slots[1];
1836         if (slot == 0)
1837                 return 1;
1838         if (!path->nodes[1])
1839                 return 1;
1840
1841         right_nritems = btrfs_header_nritems(right);
1842         if (right_nritems == 0) {
1843                 return 1;
1844         }
1845
1846         left = read_node_slot(fs_info, path->nodes[1], slot - 1);
1847         free_space = btrfs_leaf_free_space(fs_info, left);
1848         if (free_space < data_size) {
1849                 free_extent_buffer(left);
1850                 return 1;
1851         }
1852
1853         /* cow and double check */
1854         ret = btrfs_cow_block(trans, root, left,
1855                               path->nodes[1], slot - 1, &left);
1856         if (ret) {
1857                 /* we hit -ENOSPC, but it isn't fatal here */
1858                 free_extent_buffer(left);
1859                 return 1;
1860         }
1861
1862         free_space = btrfs_leaf_free_space(fs_info, left);
1863         if (free_space < data_size) {
1864                 free_extent_buffer(left);
1865                 return 1;
1866         }
1867
1868         if (empty)
1869                 nr = right_nritems;
1870         else
1871                 nr = right_nritems - 1;
1872
1873         for (i = 0; i < nr; i++) {
1874                 item = btrfs_item_nr(i);
1875
1876                 if (path->slots[0] == i)
1877                         push_space += data_size + sizeof(*item);
1878
1879                 this_item_size = btrfs_item_size(right, item);
1880                 if (this_item_size + sizeof(*item) + push_space > free_space)
1881                         break;
1882
1883                 push_items++;
1884                 push_space += this_item_size + sizeof(*item);
1885         }
1886
1887         if (push_items == 0) {
1888                 free_extent_buffer(left);
1889                 return 1;
1890         }
1891         if (!empty && push_items == btrfs_header_nritems(right))
1892                 WARN_ON(1);
1893
1894         /* push data from right to left */
1895         copy_extent_buffer(left, right,
1896                            btrfs_item_nr_offset(btrfs_header_nritems(left)),
1897                            btrfs_item_nr_offset(0),
1898                            push_items * sizeof(struct btrfs_item));
1899
1900         push_space = BTRFS_LEAF_DATA_SIZE(root->fs_info) -
1901                      btrfs_item_offset_nr(right, push_items -1);
1902
1903         copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1904                      leaf_data_end(fs_info, left) - push_space,
1905                      btrfs_leaf_data(right) +
1906                      btrfs_item_offset_nr(right, push_items - 1),
1907                      push_space);
1908         old_left_nritems = btrfs_header_nritems(left);
1909         BUG_ON(old_left_nritems == 0);
1910
1911         old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1912         for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1913                 u32 ioff;
1914
1915                 item = btrfs_item_nr(i);
1916                 ioff = btrfs_item_offset(left, item);
1917                 btrfs_set_item_offset(left, item,
1918                       ioff - (BTRFS_LEAF_DATA_SIZE(root->fs_info) -
1919                               old_left_item_size));
1920         }
1921         btrfs_set_header_nritems(left, old_left_nritems + push_items);
1922
1923         /* fixup right node */
1924         if (push_items > right_nritems) {
1925                 printk("push items %d nr %u\n", push_items, right_nritems);
1926                 WARN_ON(1);
1927         }
1928
1929         if (push_items < right_nritems) {
1930                 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1931                                                   leaf_data_end(fs_info, right);
1932                 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1933                                       BTRFS_LEAF_DATA_SIZE(root->fs_info) -
1934                                       push_space,
1935                                       btrfs_leaf_data(right) +
1936                                       leaf_data_end(fs_info, right),
1937                                       push_space);
1938
1939                 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1940                               btrfs_item_nr_offset(push_items),
1941                              (btrfs_header_nritems(right) - push_items) *
1942                              sizeof(struct btrfs_item));
1943         }
1944         right_nritems -= push_items;
1945         btrfs_set_header_nritems(right, right_nritems);
1946         push_space = BTRFS_LEAF_DATA_SIZE(root->fs_info);
1947         for (i = 0; i < right_nritems; i++) {
1948                 item = btrfs_item_nr(i);
1949                 push_space = push_space - btrfs_item_size(right, item);
1950                 btrfs_set_item_offset(right, item, push_space);
1951         }
1952
1953         btrfs_mark_buffer_dirty(left);
1954         if (right_nritems)
1955                 btrfs_mark_buffer_dirty(right);
1956
1957         btrfs_item_key(right, &disk_key, 0);
1958         btrfs_fixup_low_keys(root, path, &disk_key, 1);
1959
1960         /* then fixup the leaf pointer in the path */
1961         if (path->slots[0] < push_items) {
1962                 path->slots[0] += old_left_nritems;
1963                 free_extent_buffer(path->nodes[0]);
1964                 path->nodes[0] = left;
1965                 path->slots[1] -= 1;
1966         } else {
1967                 free_extent_buffer(left);
1968                 path->slots[0] -= push_items;
1969         }
1970         BUG_ON(path->slots[0] < 0);
1971         return ret;
1972 }
1973
1974 /*
1975  * split the path's leaf in two, making sure there is at least data_size
1976  * available for the resulting leaf level of the path.
1977  *
1978  * returns 0 if all went well and < 0 on failure.
1979  */
1980 static noinline int copy_for_split(struct btrfs_trans_handle *trans,
1981                                struct btrfs_root *root,
1982                                struct btrfs_path *path,
1983                                struct extent_buffer *l,
1984                                struct extent_buffer *right,
1985                                int slot, int mid, int nritems)
1986 {
1987         int data_copy_size;
1988         int rt_data_off;
1989         int i;
1990         int ret = 0;
1991         int wret;
1992         struct btrfs_disk_key disk_key;
1993
1994         nritems = nritems - mid;
1995         btrfs_set_header_nritems(right, nritems);
1996         data_copy_size = btrfs_item_end_nr(l, mid) -
1997                 leaf_data_end(root->fs_info, l);
1998
1999         copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2000                            btrfs_item_nr_offset(mid),
2001                            nritems * sizeof(struct btrfs_item));
2002
2003         copy_extent_buffer(right, l,
2004                      btrfs_leaf_data(right) +
2005                      BTRFS_LEAF_DATA_SIZE(root->fs_info) -
2006                      data_copy_size, btrfs_leaf_data(l) +
2007                      leaf_data_end(root->fs_info, l), data_copy_size);
2008
2009         rt_data_off = BTRFS_LEAF_DATA_SIZE(root->fs_info) -
2010                       btrfs_item_end_nr(l, mid);
2011
2012         for (i = 0; i < nritems; i++) {
2013                 struct btrfs_item *item = btrfs_item_nr(i);
2014                 u32 ioff = btrfs_item_offset(right, item);
2015                 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2016         }
2017
2018         btrfs_set_header_nritems(l, mid);
2019         ret = 0;
2020         btrfs_item_key(right, &disk_key, 0);
2021         wret = insert_ptr(trans, root, path, &disk_key, right->start,
2022                           path->slots[1] + 1, 1);
2023         if (wret)
2024                 ret = wret;
2025
2026         btrfs_mark_buffer_dirty(right);
2027         btrfs_mark_buffer_dirty(l);
2028         BUG_ON(path->slots[0] != slot);
2029
2030         if (mid <= slot) {
2031                 free_extent_buffer(path->nodes[0]);
2032                 path->nodes[0] = right;
2033                 path->slots[0] -= mid;
2034                 path->slots[1] += 1;
2035         } else {
2036                 free_extent_buffer(right);
2037         }
2038
2039         BUG_ON(path->slots[0] < 0);
2040
2041         return ret;
2042 }
2043
2044 /*
2045  * split the path's leaf in two, making sure there is at least data_size
2046  * available for the resulting leaf level of the path.
2047  *
2048  * returns 0 if all went well and < 0 on failure.
2049  */
2050 static noinline int split_leaf(struct btrfs_trans_handle *trans,
2051                                struct btrfs_root *root,
2052                                struct btrfs_key *ins_key,
2053                                struct btrfs_path *path, int data_size,
2054                                int extend)
2055 {
2056         struct btrfs_disk_key disk_key;
2057         struct extent_buffer *l;
2058         u32 nritems;
2059         int mid;
2060         int slot;
2061         struct extent_buffer *right;
2062         int ret = 0;
2063         int wret;
2064         int split;
2065         int num_doubles = 0;
2066
2067         l = path->nodes[0];
2068         slot = path->slots[0];
2069         if (extend && data_size + btrfs_item_size_nr(l, slot) +
2070             sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info))
2071                 return -EOVERFLOW;
2072
2073         /* first try to make some room by pushing left and right */
2074         if (data_size && ins_key->type != BTRFS_DIR_ITEM_KEY) {
2075                 wret = push_leaf_right(trans, root, path, data_size, 0);
2076                 if (wret < 0)
2077                         return wret;
2078                 if (wret) {
2079                         wret = push_leaf_left(trans, root, path, data_size, 0);
2080                         if (wret < 0)
2081                                 return wret;
2082                 }
2083                 l = path->nodes[0];
2084
2085                 /* did the pushes work? */
2086                 if (btrfs_leaf_free_space(root->fs_info, l) >= data_size)
2087                         return 0;
2088         }
2089
2090         if (!path->nodes[1]) {
2091                 ret = insert_new_root(trans, root, path, 1);
2092                 if (ret)
2093                         return ret;
2094         }
2095 again:
2096         split = 1;
2097         l = path->nodes[0];
2098         slot = path->slots[0];
2099         nritems = btrfs_header_nritems(l);
2100         mid = (nritems + 1) / 2;
2101
2102         if (mid <= slot) {
2103                 if (nritems == 1 ||
2104                     leaf_space_used(l, mid, nritems - mid) + data_size >
2105                         BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
2106                         if (slot >= nritems) {
2107                                 split = 0;
2108                         } else {
2109                                 mid = slot;
2110                                 if (mid != nritems &&
2111                                     leaf_space_used(l, mid, nritems - mid) +
2112                                     data_size >
2113                                     BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
2114                                         split = 2;
2115                                 }
2116                         }
2117                 }
2118         } else {
2119                 if (leaf_space_used(l, 0, mid) + data_size >
2120                         BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
2121                         if (!extend && data_size && slot == 0) {
2122                                 split = 0;
2123                         } else if ((extend || !data_size) && slot == 0) {
2124                                 mid = 1;
2125                         } else {
2126                                 mid = slot;
2127                                 if (mid != nritems &&
2128                                     leaf_space_used(l, mid, nritems - mid) +
2129                                     data_size >
2130                                     BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
2131                                         split = 2 ;
2132                                 }
2133                         }
2134                 }
2135         }
2136
2137         if (split == 0)
2138                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2139         else
2140                 btrfs_item_key(l, &disk_key, mid);
2141
2142         right = btrfs_alloc_free_block(trans, root, root->fs_info->nodesize,
2143                                         root->root_key.objectid,
2144                                         &disk_key, 0, l->start, 0);
2145         if (IS_ERR(right)) {
2146                 BUG_ON(1);
2147                 return PTR_ERR(right);
2148         }
2149
2150         memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2151         btrfs_set_header_bytenr(right, right->start);
2152         btrfs_set_header_generation(right, trans->transid);
2153         btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV);
2154         btrfs_set_header_owner(right, root->root_key.objectid);
2155         btrfs_set_header_level(right, 0);
2156         write_extent_buffer(right, root->fs_info->fsid,
2157                             btrfs_header_fsid(), BTRFS_FSID_SIZE);
2158
2159         write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2160                             btrfs_header_chunk_tree_uuid(right),
2161                             BTRFS_UUID_SIZE);
2162
2163         if (split == 0) {
2164                 if (mid <= slot) {
2165                         btrfs_set_header_nritems(right, 0);
2166                         wret = insert_ptr(trans, root, path,
2167                                           &disk_key, right->start,
2168                                           path->slots[1] + 1, 1);
2169                         if (wret)
2170                                 ret = wret;
2171
2172                         free_extent_buffer(path->nodes[0]);
2173                         path->nodes[0] = right;
2174                         path->slots[0] = 0;
2175                         path->slots[1] += 1;
2176                 } else {
2177                         btrfs_set_header_nritems(right, 0);
2178                         wret = insert_ptr(trans, root, path,
2179                                           &disk_key,
2180                                           right->start,
2181                                           path->slots[1], 1);
2182                         if (wret)
2183                                 ret = wret;
2184                         free_extent_buffer(path->nodes[0]);
2185                         path->nodes[0] = right;
2186                         path->slots[0] = 0;
2187                         if (path->slots[1] == 0) {
2188                                 btrfs_fixup_low_keys(root, path,
2189                                                      &disk_key, 1);
2190                         }
2191                 }
2192                 btrfs_mark_buffer_dirty(right);
2193                 return ret;
2194         }
2195
2196         ret = copy_for_split(trans, root, path, l, right, slot, mid, nritems);
2197         BUG_ON(ret);
2198
2199         if (split == 2) {
2200                 BUG_ON(num_doubles != 0);
2201                 num_doubles++;
2202                 goto again;
2203         }
2204
2205         return ret;
2206 }
2207
2208 /*
2209  * This function splits a single item into two items,
2210  * giving 'new_key' to the new item and splitting the
2211  * old one at split_offset (from the start of the item).
2212  *
2213  * The path may be released by this operation.  After
2214  * the split, the path is pointing to the old item.  The
2215  * new item is going to be in the same node as the old one.
2216  *
2217  * Note, the item being split must be smaller enough to live alone on
2218  * a tree block with room for one extra struct btrfs_item
2219  *
2220  * This allows us to split the item in place, keeping a lock on the
2221  * leaf the entire time.
2222  */
2223 int btrfs_split_item(struct btrfs_trans_handle *trans,
2224                      struct btrfs_root *root,
2225                      struct btrfs_path *path,
2226                      struct btrfs_key *new_key,
2227                      unsigned long split_offset)
2228 {
2229         u32 item_size;
2230         struct extent_buffer *leaf;
2231         struct btrfs_key orig_key;
2232         struct btrfs_item *item;
2233         struct btrfs_item *new_item;
2234         int ret = 0;
2235         int slot;
2236         u32 nritems;
2237         u32 orig_offset;
2238         struct btrfs_disk_key disk_key;
2239         char *buf;
2240
2241         leaf = path->nodes[0];
2242         btrfs_item_key_to_cpu(leaf, &orig_key, path->slots[0]);
2243         if (btrfs_leaf_free_space(root->fs_info, leaf) >=
2244             sizeof(struct btrfs_item))
2245                 goto split;
2246
2247         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2248         btrfs_release_path(path);
2249
2250         path->search_for_split = 1;
2251
2252         ret = btrfs_search_slot(trans, root, &orig_key, path, 0, 1);
2253         path->search_for_split = 0;
2254
2255         /* if our item isn't there or got smaller, return now */
2256         if (ret != 0 || item_size != btrfs_item_size_nr(path->nodes[0],
2257                                                         path->slots[0])) {
2258                 return -EAGAIN;
2259         }
2260
2261         ret = split_leaf(trans, root, &orig_key, path, 0, 0);
2262         BUG_ON(ret);
2263
2264         BUG_ON(btrfs_leaf_free_space(root->fs_info, leaf) <
2265                sizeof(struct btrfs_item));
2266         leaf = path->nodes[0];
2267
2268 split:
2269         item = btrfs_item_nr(path->slots[0]);
2270         orig_offset = btrfs_item_offset(leaf, item);
2271         item_size = btrfs_item_size(leaf, item);
2272
2273
2274         buf = kmalloc(item_size, GFP_NOFS);
2275         BUG_ON(!buf);
2276         read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
2277                             path->slots[0]), item_size);
2278         slot = path->slots[0] + 1;
2279         leaf = path->nodes[0];
2280
2281         nritems = btrfs_header_nritems(leaf);
2282
2283         if (slot < nritems) {
2284                 /* shift the items */
2285                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
2286                               btrfs_item_nr_offset(slot),
2287                               (nritems - slot) * sizeof(struct btrfs_item));
2288
2289         }
2290
2291         btrfs_cpu_key_to_disk(&disk_key, new_key);
2292         btrfs_set_item_key(leaf, &disk_key, slot);
2293
2294         new_item = btrfs_item_nr(slot);
2295
2296         btrfs_set_item_offset(leaf, new_item, orig_offset);
2297         btrfs_set_item_size(leaf, new_item, item_size - split_offset);
2298
2299         btrfs_set_item_offset(leaf, item,
2300                               orig_offset + item_size - split_offset);
2301         btrfs_set_item_size(leaf, item, split_offset);
2302
2303         btrfs_set_header_nritems(leaf, nritems + 1);
2304
2305         /* write the data for the start of the original item */
2306         write_extent_buffer(leaf, buf,
2307                             btrfs_item_ptr_offset(leaf, path->slots[0]),
2308                             split_offset);
2309
2310         /* write the data for the new item */
2311         write_extent_buffer(leaf, buf + split_offset,
2312                             btrfs_item_ptr_offset(leaf, slot),
2313                             item_size - split_offset);
2314         btrfs_mark_buffer_dirty(leaf);
2315
2316         ret = 0;
2317         if (btrfs_leaf_free_space(root->fs_info, leaf) < 0) {
2318                 btrfs_print_leaf(leaf);
2319                 BUG();
2320         }
2321         kfree(buf);
2322         return ret;
2323 }
2324
2325 int btrfs_truncate_item(struct btrfs_root *root, struct btrfs_path *path,
2326                         u32 new_size, int from_end)
2327 {
2328         int ret = 0;
2329         int slot;
2330         struct extent_buffer *leaf;
2331         struct btrfs_item *item;
2332         u32 nritems;
2333         unsigned int data_end;
2334         unsigned int old_data_start;
2335         unsigned int old_size;
2336         unsigned int size_diff;
2337         int i;
2338
2339         leaf = path->nodes[0];
2340         slot = path->slots[0];
2341
2342         old_size = btrfs_item_size_nr(leaf, slot);
2343         if (old_size == new_size)
2344                 return 0;
2345
2346         nritems = btrfs_header_nritems(leaf);
2347         data_end = leaf_data_end(root->fs_info, leaf);
2348
2349         old_data_start = btrfs_item_offset_nr(leaf, slot);
2350
2351         size_diff = old_size - new_size;
2352
2353         BUG_ON(slot < 0);
2354         BUG_ON(slot >= nritems);
2355
2356         /*
2357          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2358          */
2359         /* first correct the data pointers */
2360         for (i = slot; i < nritems; i++) {
2361                 u32 ioff;
2362                 item = btrfs_item_nr(i);
2363                 ioff = btrfs_item_offset(leaf, item);
2364                 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2365         }
2366
2367         /* shift the data */
2368         if (from_end) {
2369                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2370                               data_end + size_diff, btrfs_leaf_data(leaf) +
2371                               data_end, old_data_start + new_size - data_end);
2372         } else {
2373                 struct btrfs_disk_key disk_key;
2374                 u64 offset;
2375
2376                 btrfs_item_key(leaf, &disk_key, slot);
2377
2378                 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2379                         unsigned long ptr;
2380                         struct btrfs_file_extent_item *fi;
2381
2382                         fi = btrfs_item_ptr(leaf, slot,
2383                                             struct btrfs_file_extent_item);
2384                         fi = (struct btrfs_file_extent_item *)(
2385                              (unsigned long)fi - size_diff);
2386
2387                         if (btrfs_file_extent_type(leaf, fi) ==
2388                             BTRFS_FILE_EXTENT_INLINE) {
2389                                 ptr = btrfs_item_ptr_offset(leaf, slot);
2390                                 memmove_extent_buffer(leaf, ptr,
2391                                         (unsigned long)fi,
2392                                         offsetof(struct btrfs_file_extent_item,
2393                                                  disk_bytenr));
2394                         }
2395                 }
2396
2397                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2398                               data_end + size_diff, btrfs_leaf_data(leaf) +
2399                               data_end, old_data_start - data_end);
2400
2401                 offset = btrfs_disk_key_offset(&disk_key);
2402                 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2403                 btrfs_set_item_key(leaf, &disk_key, slot);
2404                 if (slot == 0)
2405                         btrfs_fixup_low_keys(root, path, &disk_key, 1);
2406         }
2407
2408         item = btrfs_item_nr(slot);
2409         btrfs_set_item_size(leaf, item, new_size);
2410         btrfs_mark_buffer_dirty(leaf);
2411
2412         ret = 0;
2413         if (btrfs_leaf_free_space(root->fs_info, leaf) < 0) {
2414                 btrfs_print_leaf(leaf);
2415                 BUG();
2416         }
2417         return ret;
2418 }
2419
2420 int btrfs_extend_item(struct btrfs_root *root, struct btrfs_path *path,
2421                       u32 data_size)
2422 {
2423         int ret = 0;
2424         int slot;
2425         struct extent_buffer *leaf;
2426         struct btrfs_item *item;
2427         u32 nritems;
2428         unsigned int data_end;
2429         unsigned int old_data;
2430         unsigned int old_size;
2431         int i;
2432
2433         leaf = path->nodes[0];
2434
2435         nritems = btrfs_header_nritems(leaf);
2436         data_end = leaf_data_end(root->fs_info, leaf);
2437
2438         if (btrfs_leaf_free_space(root->fs_info, leaf) < data_size) {
2439                 btrfs_print_leaf(leaf);
2440                 BUG();
2441         }
2442         slot = path->slots[0];
2443         old_data = btrfs_item_end_nr(leaf, slot);
2444
2445         BUG_ON(slot < 0);
2446         if (slot >= nritems) {
2447                 btrfs_print_leaf(leaf);
2448                 printk("slot %d too large, nritems %d\n", slot, nritems);
2449                 BUG_ON(1);
2450         }
2451
2452         /*
2453          * item0..itemN ... dataN.offset..dataN.size .. data0.size
2454          */
2455         /* first correct the data pointers */
2456         for (i = slot; i < nritems; i++) {
2457                 u32 ioff;
2458                 item = btrfs_item_nr(i);
2459                 ioff = btrfs_item_offset(leaf, item);
2460                 btrfs_set_item_offset(leaf, item, ioff - data_size);
2461         }
2462
2463         /* shift the data */
2464         memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2465                       data_end - data_size, btrfs_leaf_data(leaf) +
2466                       data_end, old_data - data_end);
2467
2468         data_end = old_data;
2469         old_size = btrfs_item_size_nr(leaf, slot);
2470         item = btrfs_item_nr(slot);
2471         btrfs_set_item_size(leaf, item, old_size + data_size);
2472         btrfs_mark_buffer_dirty(leaf);
2473
2474         ret = 0;
2475         if (btrfs_leaf_free_space(root->fs_info, leaf) < 0) {
2476                 btrfs_print_leaf(leaf);
2477                 BUG();
2478         }
2479         return ret;
2480 }
2481
2482 /*
2483  * Given a key and some data, insert an item into the tree.
2484  * This does all the path init required, making room in the tree if needed.
2485  */
2486 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2487                             struct btrfs_root *root,
2488                             struct btrfs_path *path,
2489                             struct btrfs_key *cpu_key, u32 *data_size,
2490                             int nr)
2491 {
2492         struct extent_buffer *leaf;
2493         struct btrfs_item *item;
2494         int ret = 0;
2495         int slot;
2496         int i;
2497         u32 nritems;
2498         u32 total_size = 0;
2499         u32 total_data = 0;
2500         unsigned int data_end;
2501         struct btrfs_disk_key disk_key;
2502
2503         for (i = 0; i < nr; i++) {
2504                 total_data += data_size[i];
2505         }
2506
2507         /* create a root if there isn't one */
2508         if (!root->node)
2509                 BUG();
2510
2511         total_size = total_data + nr * sizeof(struct btrfs_item);
2512         ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2513         if (ret == 0) {
2514                 return -EEXIST;
2515         }
2516         if (ret < 0)
2517                 goto out;
2518
2519         leaf = path->nodes[0];
2520
2521         nritems = btrfs_header_nritems(leaf);
2522         data_end = leaf_data_end(root->fs_info, leaf);
2523
2524         if (btrfs_leaf_free_space(root->fs_info, leaf) < total_size) {
2525                 btrfs_print_leaf(leaf);
2526                 printk("not enough freespace need %u have %d\n",
2527                        total_size, btrfs_leaf_free_space(root->fs_info, leaf));
2528                 BUG();
2529         }
2530
2531         slot = path->slots[0];
2532         BUG_ON(slot < 0);
2533
2534         if (slot < nritems) {
2535                 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2536
2537                 if (old_data < data_end) {
2538                         btrfs_print_leaf(leaf);
2539                         printk("slot %d old_data %d data_end %d\n",
2540                                slot, old_data, data_end);
2541                         BUG_ON(1);
2542                 }
2543                 /*
2544                  * item0..itemN ... dataN.offset..dataN.size .. data0.size
2545                  */
2546                 /* first correct the data pointers */
2547                 for (i = slot; i < nritems; i++) {
2548                         u32 ioff;
2549
2550                         item = btrfs_item_nr(i);
2551                         ioff = btrfs_item_offset(leaf, item);
2552                         btrfs_set_item_offset(leaf, item, ioff - total_data);
2553                 }
2554
2555                 /* shift the items */
2556                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2557                               btrfs_item_nr_offset(slot),
2558                               (nritems - slot) * sizeof(struct btrfs_item));
2559
2560                 /* shift the data */
2561                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2562                               data_end - total_data, btrfs_leaf_data(leaf) +
2563                               data_end, old_data - data_end);
2564                 data_end = old_data;
2565         }
2566
2567         /* setup the item for the new data */
2568         for (i = 0; i < nr; i++) {
2569                 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2570                 btrfs_set_item_key(leaf, &disk_key, slot + i);
2571                 item = btrfs_item_nr(slot + i);
2572                 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2573                 data_end -= data_size[i];
2574                 btrfs_set_item_size(leaf, item, data_size[i]);
2575         }
2576         btrfs_set_header_nritems(leaf, nritems + nr);
2577         btrfs_mark_buffer_dirty(leaf);
2578
2579         ret = 0;
2580         if (slot == 0) {
2581                 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2582                 btrfs_fixup_low_keys(root, path, &disk_key, 1);
2583         }
2584
2585         if (btrfs_leaf_free_space(root->fs_info, leaf) < 0) {
2586                 btrfs_print_leaf(leaf);
2587                 BUG();
2588         }
2589
2590 out:
2591         return ret;
2592 }
2593
2594 /*
2595  * Given a key and some data, insert an item into the tree.
2596  * This does all the path init required, making room in the tree if needed.
2597  */
2598 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2599                       *root, struct btrfs_key *cpu_key, void *data, u32
2600                       data_size)
2601 {
2602         int ret = 0;
2603         struct btrfs_path *path;
2604         struct extent_buffer *leaf;
2605         unsigned long ptr;
2606
2607         path = btrfs_alloc_path();
2608         if (!path)
2609                 return -ENOMEM;
2610
2611         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2612         if (!ret) {
2613                 leaf = path->nodes[0];
2614                 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2615                 write_extent_buffer(leaf, data, ptr, data_size);
2616                 btrfs_mark_buffer_dirty(leaf);
2617         }
2618         btrfs_free_path(path);
2619         return ret;
2620 }
2621
2622 /*
2623  * delete the pointer from a given node.
2624  *
2625  * If the delete empties a node, the node is removed from the tree,
2626  * continuing all the way the root if required.  The root is converted into
2627  * a leaf if all the nodes are emptied.
2628  */
2629 int btrfs_del_ptr(struct btrfs_root *root, struct btrfs_path *path,
2630                 int level, int slot)
2631 {
2632         struct extent_buffer *parent = path->nodes[level];
2633         u32 nritems;
2634         int ret = 0;
2635
2636         nritems = btrfs_header_nritems(parent);
2637         if (slot < nritems - 1) {
2638                 /* shift the items */
2639                 memmove_extent_buffer(parent,
2640                               btrfs_node_key_ptr_offset(slot),
2641                               btrfs_node_key_ptr_offset(slot + 1),
2642                               sizeof(struct btrfs_key_ptr) *
2643                               (nritems - slot - 1));
2644         }
2645         nritems--;
2646         btrfs_set_header_nritems(parent, nritems);
2647         if (nritems == 0 && parent == root->node) {
2648                 BUG_ON(btrfs_header_level(root->node) != 1);
2649                 /* just turn the root into a leaf and break */
2650                 btrfs_set_header_level(root->node, 0);
2651         } else if (slot == 0) {
2652                 struct btrfs_disk_key disk_key;
2653
2654                 btrfs_node_key(parent, &disk_key, 0);
2655                 btrfs_fixup_low_keys(root, path, &disk_key, level + 1);
2656         }
2657         btrfs_mark_buffer_dirty(parent);
2658         return ret;
2659 }
2660
2661 /*
2662  * a helper function to delete the leaf pointed to by path->slots[1] and
2663  * path->nodes[1].
2664  *
2665  * This deletes the pointer in path->nodes[1] and frees the leaf
2666  * block extent.  zero is returned if it all worked out, < 0 otherwise.
2667  *
2668  * The path must have already been setup for deleting the leaf, including
2669  * all the proper balancing.  path->nodes[1] must be locked.
2670  */
2671 static noinline int btrfs_del_leaf(struct btrfs_trans_handle *trans,
2672                                    struct btrfs_root *root,
2673                                    struct btrfs_path *path,
2674                                    struct extent_buffer *leaf)
2675 {
2676         int ret;
2677
2678         WARN_ON(btrfs_header_generation(leaf) != trans->transid);
2679         ret = btrfs_del_ptr(root, path, 1, path->slots[1]);
2680         if (ret)
2681                 return ret;
2682
2683         ret = btrfs_free_extent(trans, root, leaf->start, leaf->len,
2684                                 0, root->root_key.objectid, 0, 0);
2685         return ret;
2686 }
2687
2688 /*
2689  * delete the item at the leaf level in path.  If that empties
2690  * the leaf, remove it from the tree
2691  */
2692 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2693                     struct btrfs_path *path, int slot, int nr)
2694 {
2695         struct extent_buffer *leaf;
2696         struct btrfs_item *item;
2697         int last_off;
2698         int dsize = 0;
2699         int ret = 0;
2700         int wret;
2701         int i;
2702         u32 nritems;
2703
2704         leaf = path->nodes[0];
2705         last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2706
2707         for (i = 0; i < nr; i++)
2708                 dsize += btrfs_item_size_nr(leaf, slot + i);
2709
2710         nritems = btrfs_header_nritems(leaf);
2711
2712         if (slot + nr != nritems) {
2713                 int data_end = leaf_data_end(root->fs_info, leaf);
2714
2715                 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2716                               data_end + dsize,
2717                               btrfs_leaf_data(leaf) + data_end,
2718                               last_off - data_end);
2719
2720                 for (i = slot + nr; i < nritems; i++) {
2721                         u32 ioff;
2722
2723                         item = btrfs_item_nr(i);
2724                         ioff = btrfs_item_offset(leaf, item);
2725                         btrfs_set_item_offset(leaf, item, ioff + dsize);
2726                 }
2727
2728                 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2729                               btrfs_item_nr_offset(slot + nr),
2730                               sizeof(struct btrfs_item) *
2731                               (nritems - slot - nr));
2732         }
2733         btrfs_set_header_nritems(leaf, nritems - nr);
2734         nritems -= nr;
2735
2736         /* delete the leaf if we've emptied it */
2737         if (nritems == 0) {
2738                 if (leaf == root->node) {
2739                         btrfs_set_header_level(leaf, 0);
2740                 } else {
2741                         clean_tree_block(trans, root, leaf);
2742                         wret = btrfs_del_leaf(trans, root, path, leaf);
2743                         BUG_ON(ret);
2744                         if (wret)
2745                                 ret = wret;
2746                 }
2747         } else {
2748                 int used = leaf_space_used(leaf, 0, nritems);
2749                 if (slot == 0) {
2750                         struct btrfs_disk_key disk_key;
2751
2752                         btrfs_item_key(leaf, &disk_key, 0);
2753                         btrfs_fixup_low_keys(root, path, &disk_key, 1);
2754                 }
2755
2756                 /* delete the leaf if it is mostly empty */
2757                 if (used < BTRFS_LEAF_DATA_SIZE(root->fs_info) / 4) {
2758                         /* push_leaf_left fixes the path.
2759                          * make sure the path still points to our leaf
2760                          * for possible call to del_ptr below
2761                          */
2762                         slot = path->slots[1];
2763                         extent_buffer_get(leaf);
2764
2765                         wret = push_leaf_left(trans, root, path, 1, 1);
2766                         if (wret < 0 && wret != -ENOSPC)
2767                                 ret = wret;
2768
2769                         if (path->nodes[0] == leaf &&
2770                             btrfs_header_nritems(leaf)) {
2771                                 wret = push_leaf_right(trans, root, path, 1, 1);
2772                                 if (wret < 0 && wret != -ENOSPC)
2773                                         ret = wret;
2774                         }
2775
2776                         if (btrfs_header_nritems(leaf) == 0) {
2777                                 clean_tree_block(trans, root, leaf);
2778                                 path->slots[1] = slot;
2779                                 ret = btrfs_del_leaf(trans, root, path, leaf);
2780                                 BUG_ON(ret);
2781                                 free_extent_buffer(leaf);
2782
2783                         } else {
2784                                 btrfs_mark_buffer_dirty(leaf);
2785                                 free_extent_buffer(leaf);
2786                         }
2787                 } else {
2788                         btrfs_mark_buffer_dirty(leaf);
2789                 }
2790         }
2791         return ret;
2792 }
2793
2794 /*
2795  * walk up the tree as far as required to find the previous leaf.
2796  * returns 0 if it found something or 1 if there are no lesser leaves.
2797  * returns < 0 on io errors.
2798  */
2799 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2800 {
2801         int slot;
2802         int level = 1;
2803         struct extent_buffer *c;
2804         struct extent_buffer *next = NULL;
2805         struct btrfs_fs_info *fs_info = root->fs_info;
2806
2807         while(level < BTRFS_MAX_LEVEL) {
2808                 if (!path->nodes[level])
2809                         return 1;
2810
2811                 slot = path->slots[level];
2812                 c = path->nodes[level];
2813                 if (slot == 0) {
2814                         level++;
2815                         if (level == BTRFS_MAX_LEVEL)
2816                                 return 1;
2817                         continue;
2818                 }
2819                 slot--;
2820
2821                 next = read_node_slot(fs_info, c, slot);
2822                 if (!extent_buffer_uptodate(next)) {
2823                         if (IS_ERR(next))
2824                                 return PTR_ERR(next);
2825                         return -EIO;
2826                 }
2827                 break;
2828         }
2829         path->slots[level] = slot;
2830         while(1) {
2831                 level--;
2832                 c = path->nodes[level];
2833                 free_extent_buffer(c);
2834                 slot = btrfs_header_nritems(next);
2835                 if (slot != 0)
2836                         slot--;
2837                 path->nodes[level] = next;
2838                 path->slots[level] = slot;
2839                 if (!level)
2840                         break;
2841                 next = read_node_slot(fs_info, next, slot);
2842                 if (!extent_buffer_uptodate(next)) {
2843                         if (IS_ERR(next))
2844                                 return PTR_ERR(next);
2845                         return -EIO;
2846                 }
2847         }
2848         return 0;
2849 }
2850
2851 /*
2852  * walk up the tree as far as required to find the next leaf.
2853  * returns 0 if it found something or 1 if there are no greater leaves.
2854  * returns < 0 on io errors.
2855  */
2856 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2857 {
2858         int slot;
2859         int level = 1;
2860         struct extent_buffer *c;
2861         struct extent_buffer *next = NULL;
2862         struct btrfs_fs_info *fs_info = root->fs_info;
2863
2864         while(level < BTRFS_MAX_LEVEL) {
2865                 if (!path->nodes[level])
2866                         return 1;
2867
2868                 slot = path->slots[level] + 1;
2869                 c = path->nodes[level];
2870                 if (slot >= btrfs_header_nritems(c)) {
2871                         level++;
2872                         if (level == BTRFS_MAX_LEVEL)
2873                                 return 1;
2874                         continue;
2875                 }
2876
2877                 if (path->reada)
2878                         reada_for_search(root, path, level, slot, 0);
2879
2880                 next = read_node_slot(fs_info, c, slot);
2881                 if (!extent_buffer_uptodate(next))
2882                         return -EIO;
2883                 break;
2884         }
2885         path->slots[level] = slot;
2886         while(1) {
2887                 level--;
2888                 c = path->nodes[level];
2889                 free_extent_buffer(c);
2890                 path->nodes[level] = next;
2891                 path->slots[level] = 0;
2892                 if (!level)
2893                         break;
2894                 if (path->reada)
2895                         reada_for_search(root, path, level, 0, 0);
2896                 next = read_node_slot(fs_info, next, 0);
2897                 if (!extent_buffer_uptodate(next))
2898                         return -EIO;
2899         }
2900         return 0;
2901 }
2902
2903 int btrfs_previous_item(struct btrfs_root *root,
2904                         struct btrfs_path *path, u64 min_objectid,
2905                         int type)
2906 {
2907         struct btrfs_key found_key;
2908         struct extent_buffer *leaf;
2909         u32 nritems;
2910         int ret;
2911
2912         while(1) {
2913                 if (path->slots[0] == 0) {
2914                         ret = btrfs_prev_leaf(root, path);
2915                         if (ret != 0)
2916                                 return ret;
2917                 } else {
2918                         path->slots[0]--;
2919                 }
2920                 leaf = path->nodes[0];
2921                 nritems = btrfs_header_nritems(leaf);
2922                 if (nritems == 0)
2923                         return 1;
2924                 if (path->slots[0] == nritems)
2925                         path->slots[0]--;
2926
2927                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2928                 if (found_key.objectid < min_objectid)
2929                         break;
2930                 if (found_key.type == type)
2931                         return 0;
2932                 if (found_key.objectid == min_objectid &&
2933                     found_key.type < type)
2934                         break;
2935         }
2936         return 1;
2937 }
2938
2939 /*
2940  * search in extent tree to find a previous Metadata/Data extent item with
2941  * min objecitd.
2942  *
2943  * returns 0 if something is found, 1 if nothing was found and < 0 on error
2944  */
2945 int btrfs_previous_extent_item(struct btrfs_root *root,
2946                         struct btrfs_path *path, u64 min_objectid)
2947 {
2948         struct btrfs_key found_key;
2949         struct extent_buffer *leaf;
2950         u32 nritems;
2951         int ret;
2952
2953         while (1) {
2954                 if (path->slots[0] == 0) {
2955                         ret = btrfs_prev_leaf(root, path);
2956                         if (ret != 0)
2957                                 return ret;
2958                 } else {
2959                         path->slots[0]--;
2960                 }
2961                 leaf = path->nodes[0];
2962                 nritems = btrfs_header_nritems(leaf);
2963                 if (nritems == 0)
2964                         return 1;
2965                 if (path->slots[0] == nritems)
2966                         path->slots[0]--;
2967
2968                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2969                 if (found_key.objectid < min_objectid)
2970                         break;
2971                 if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
2972                     found_key.type == BTRFS_METADATA_ITEM_KEY)
2973                         return 0;
2974                 if (found_key.objectid == min_objectid &&
2975                     found_key.type < BTRFS_EXTENT_ITEM_KEY)
2976                         break;
2977         }
2978         return 1;
2979 }
2980
2981 /*
2982  * Search in extent tree to found next meta/data extent
2983  * Caller needs to check for no-hole or skinny metadata features.
2984  */
2985 int btrfs_next_extent_item(struct btrfs_root *root,
2986                         struct btrfs_path *path, u64 max_objectid)
2987 {
2988         struct btrfs_key found_key;
2989         int ret;
2990
2991         while (1) {
2992                 ret = btrfs_next_item(root, path);
2993                 if (ret)
2994                         return ret;
2995                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2996                                       path->slots[0]);
2997                 if (found_key.objectid > max_objectid)
2998                         return 1;
2999                 if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
3000                     found_key.type == BTRFS_METADATA_ITEM_KEY)
3001                 return 0;
3002         }
3003 }