fs/btrfs/ctree.c

   1 #include <linux/module.h>
   2 #include "ctree.h"
   3 #include "disk-io.h"
   4 #include "transaction.h"
   5
   6 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
   7                       *root, struct btrfs_path *path, int level);
   8 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
   9                       *root, struct btrfs_key *ins_key,
  10                       struct btrfs_path *path, int data_size);
  11 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
  12                           *root, struct buffer_head *dst, struct buffer_head
  13                           *src);
  14 static int balance_node_right(struct btrfs_trans_handle *trans, struct
  15                               btrfs_root *root, struct buffer_head *dst_buf,
  16                               struct buffer_head *src_buf);
  17 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  18                    struct btrfs_path *path, int level, int slot);
  19
  20 inline void btrfs_init_path(struct btrfs_path *p)
  21 {
  22         memset(p, 0, sizeof(*p));
  23 }
  24
  25 struct btrfs_path *btrfs_alloc_path(void)
  26 {
  27         struct btrfs_path *path;
  28         path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
  29         if (path)
  30                 btrfs_init_path(path);
  31         return path;
  32 }
  33
  34 void btrfs_free_path(struct btrfs_path *p)
  35 {
  36         btrfs_release_path(NULL, p);
  37         kmem_cache_free(btrfs_path_cachep, p);
  38 }
  39
  40 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
  41 {
  42         int i;
  43         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
  44                 if (!p->nodes[i])
  45                         break;
  46                 btrfs_block_release(root, p->nodes[i]);
  47         }
  48         memset(p, 0, sizeof(*p));
  49 }
  50
  51 static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
  52                            *root, struct buffer_head *buf, struct buffer_head
  53                            *parent, int parent_slot, struct buffer_head
  54                            **cow_ret)
  55 {
  56         struct buffer_head *cow;
  57         struct btrfs_node *cow_node;
  58
  59         if (btrfs_header_generation(btrfs_buffer_header(buf)) ==
  60                                     trans->transid) {
  61                 *cow_ret = buf;
  62                 return 0;
  63         }
  64         cow = btrfs_alloc_free_block(trans, root);
  65         cow_node = btrfs_buffer_node(cow);
  66         if (buf->b_size != root->blocksize || cow->b_size != root->blocksize)
  67                 WARN_ON(1);
  68         memcpy(cow_node, btrfs_buffer_node(buf), root->blocksize);
  69         btrfs_set_header_blocknr(&cow_node->header, bh_blocknr(cow));
  70         btrfs_set_header_generation(&cow_node->header, trans->transid);
  71         btrfs_inc_ref(trans, root, buf);
  72         if (buf == root->node) {
  73                 root->node = cow;
  74                 get_bh(cow);
  75                 if (buf != root->commit_root) {
  76                         btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
  77                 }
  78                 btrfs_block_release(root, buf);
  79         } else {
  80                 btrfs_set_node_blockptr(btrfs_buffer_node(parent), parent_slot,
  81                                         bh_blocknr(cow));
  82                 btrfs_mark_buffer_dirty(parent);
  83                 btrfs_free_extent(trans, root, bh_blocknr(buf), 1, 1);
  84         }
  85         btrfs_block_release(root, buf);
  86         mark_buffer_dirty(cow);
  87         *cow_ret = cow;
  88         return 0;
  89 }
  90
  91 /*
  92  * The leaf data grows from end-to-front in the node.
  93  * this returns the address of the start of the last item,
  94  * which is the stop of the leaf data stack
  95  */
  96 static inline unsigned int leaf_data_end(struct btrfs_root *root,
  97                                          struct btrfs_leaf *leaf)
  98 {
  99         u32 nr = btrfs_header_nritems(&leaf->header);
 100         if (nr == 0)
 101                 return BTRFS_LEAF_DATA_SIZE(root);
 102         return btrfs_item_offset(leaf->items + nr - 1);
 103 }
 104
 105 /*
 106  * compare two keys in a memcmp fashion
 107  */
 108 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
 109 {
 110         struct btrfs_key k1;
 111
 112         btrfs_disk_key_to_cpu(&k1, disk);
 113
 114         if (k1.objectid > k2->objectid)
 115                 return 1;
 116         if (k1.objectid < k2->objectid)
 117                 return -1;
 118         if (k1.flags > k2->flags)
 119                 return 1;
 120         if (k1.flags < k2->flags)
 121                 return -1;
 122         if (k1.offset > k2->offset)
 123                 return 1;
 124         if (k1.offset < k2->offset)
 125                 return -1;
 126         return 0;
 127 }
 128
 129 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
 130                       int level)
 131 {
 132         int i;
 133         struct btrfs_node *parent = NULL;
 134         struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]);
 135         int parent_slot;
 136         u32 nritems = btrfs_header_nritems(&node->header);
 137
 138         if (path->nodes[level + 1])
 139                 parent = btrfs_buffer_node(path->nodes[level + 1]);
 140         parent_slot = path->slots[level + 1];
 141         BUG_ON(nritems == 0);
 142         if (parent) {
 143                 struct btrfs_disk_key *parent_key;
 144                 parent_key = &parent->ptrs[parent_slot].key;
 145                 BUG_ON(memcmp(parent_key, &node->ptrs[0].key,
 146                               sizeof(struct btrfs_disk_key)));
 147                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 148                        btrfs_header_blocknr(&node->header));
 149         }
 150         BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
 151         for (i = 0; nritems > 1 && i < nritems - 2; i++) {
 152                 struct btrfs_key cpukey;
 153                 btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[i + 1].key);
 154                 BUG_ON(comp_keys(&node->ptrs[i].key, &cpukey) >= 0);
 155         }
 156         return 0;
 157 }
 158
 159 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
 160                       int level)
 161 {
 162         int i;
 163         struct btrfs_leaf *leaf = btrfs_buffer_leaf(path->nodes[level]);
 164         struct btrfs_node *parent = NULL;
 165         int parent_slot;
 166         u32 nritems = btrfs_header_nritems(&leaf->header);
 167
 168         if (path->nodes[level + 1])
 169                 parent = btrfs_buffer_node(path->nodes[level + 1]);
 170         parent_slot = path->slots[level + 1];
 171         BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
 172
 173         if (nritems == 0)
 174                 return 0;
 175
 176         if (parent) {
 177                 struct btrfs_disk_key *parent_key;
 178                 parent_key = &parent->ptrs[parent_slot].key;
 179                 BUG_ON(memcmp(parent_key, &leaf->items[0].key,
 180                        sizeof(struct btrfs_disk_key)));
 181                 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
 182                        btrfs_header_blocknr(&leaf->header));
 183         }
 184         for (i = 0; nritems > 1 && i < nritems - 2; i++) {
 185                 struct btrfs_key cpukey;
 186                 btrfs_disk_key_to_cpu(&cpukey, &leaf->items[i + 1].key);
 187                 BUG_ON(comp_keys(&leaf->items[i].key,
 188                                  &cpukey) >= 0);
 189                 BUG_ON(btrfs_item_offset(leaf->items + i) !=
 190                         btrfs_item_end(leaf->items + i + 1));
 191                 if (i == 0) {
 192                         BUG_ON(btrfs_item_offset(leaf->items + i) +
 193                                btrfs_item_size(leaf->items + i) !=
 194                                BTRFS_LEAF_DATA_SIZE(root));
 195                 }
 196         }
 197         return 0;
 198 }
 199
 200 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
 201                         int level)
 202 {
 203         struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]);
 204         if (memcmp(node->header.fsid, root->fs_info->disk_super->fsid,
 205                    sizeof(node->header.fsid)))
 206                 BUG();
 207         if (level == 0)
 208                 return check_leaf(root, path, level);
 209         return check_node(root, path, level);
 210 }
 211
 212 /*
 213  * search for key in the array p.  items p are item_size apart
 214  * and there are 'max' items in p
 215  * the slot in the array is returned via slot, and it points to
 216  * the place where you would insert key if it is not found in
 217  * the array.
 218  *
 219  * slot may point to max if the key is bigger than all of the keys
 220  */
 221 static int generic_bin_search(char *p, int item_size, struct btrfs_key *key,
 222                        int max, int *slot)
 223 {
 224         int low = 0;
 225         int high = max;
 226         int mid;
 227         int ret;
 228         struct btrfs_disk_key *tmp;
 229
 230         while(low < high) {
 231                 mid = (low + high) / 2;
 232                 tmp = (struct btrfs_disk_key *)(p + mid * item_size);
 233                 ret = comp_keys(tmp, key);
 234
 235                 if (ret < 0)
 236                         low = mid + 1;
 237                 else if (ret > 0)
 238                         high = mid;
 239                 else {
 240                         *slot = mid;
 241                         return 0;
 242                 }
 243         }
 244         *slot = low;
 245         return 1;
 246 }
 247
 248 /*
 249  * simple bin_search frontend that does the right thing for
 250  * leaves vs nodes
 251  */
 252 static int bin_search(struct btrfs_node *c, struct btrfs_key *key, int *slot)
 253 {
 254         if (btrfs_is_leaf(c)) {
 255                 struct btrfs_leaf *l = (struct btrfs_leaf *)c;
 256                 return generic_bin_search((void *)l->items,
 257                                           sizeof(struct btrfs_item),
 258                                           key, btrfs_header_nritems(&c->header),
 259                                           slot);
 260         } else {
 261                 return generic_bin_search((void *)c->ptrs,
 262                                           sizeof(struct btrfs_key_ptr),
 263                                           key, btrfs_header_nritems(&c->header),
 264                                           slot);
 265         }
 266         return -1;
 267 }
 268
 269 static struct buffer_head *read_node_slot(struct btrfs_root *root,
 270                                    struct buffer_head *parent_buf,
 271                                    int slot)
 272 {
 273         struct btrfs_node *node = btrfs_buffer_node(parent_buf);
 274         if (slot < 0)
 275                 return NULL;
 276         if (slot >= btrfs_header_nritems(&node->header))
 277                 return NULL;
 278         return read_tree_block(root, btrfs_node_blockptr(node, slot));
 279 }
 280
 281 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
 282                          *root, struct btrfs_path *path, int level)
 283 {
 284         struct buffer_head *right_buf;
 285         struct buffer_head *mid_buf;
 286         struct buffer_head *left_buf;
 287         struct buffer_head *parent_buf = NULL;
 288         struct btrfs_node *right = NULL;
 289         struct btrfs_node *mid;
 290         struct btrfs_node *left = NULL;
 291         struct btrfs_node *parent = NULL;
 292         int ret = 0;
 293         int wret;
 294         int pslot;
 295         int orig_slot = path->slots[level];
 296         u64 orig_ptr;
 297
 298         if (level == 0)
 299                 return 0;
 300
 301         mid_buf = path->nodes[level];
 302         mid = btrfs_buffer_node(mid_buf);
 303         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 304
 305         if (level < BTRFS_MAX_LEVEL - 1)
 306                 parent_buf = path->nodes[level + 1];
 307         pslot = path->slots[level + 1];
 308
 309         /*
 310          * deal with the case where there is only one pointer in the root
 311          * by promoting the node below to a root
 312          */
 313         if (!parent_buf) {
 314                 struct buffer_head *child;
 315                 u64 blocknr = bh_blocknr(mid_buf);
 316
 317                 if (btrfs_header_nritems(&mid->header) != 1)
 318                         return 0;
 319
 320                 /* promote the child to a root */
 321                 child = read_node_slot(root, mid_buf, 0);
 322                 BUG_ON(!child);
 323                 root->node = child;
 324                 path->nodes[level] = NULL;
 325                 clean_tree_block(trans, root, mid_buf);
 326                 wait_on_buffer(mid_buf);
 327                 /* once for the path */
 328                 btrfs_block_release(root, mid_buf);
 329                 /* once for the root ptr */
 330                 btrfs_block_release(root, mid_buf);
 331                 return btrfs_free_extent(trans, root, blocknr, 1, 1);
 332         }
 333         parent = btrfs_buffer_node(parent_buf);
 334
 335         if (btrfs_header_nritems(&mid->header) >
 336             BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
 337                 return 0;
 338
 339         left_buf = read_node_slot(root, parent_buf, pslot - 1);
 340         right_buf = read_node_slot(root, parent_buf, pslot + 1);
 341
 342         /* first, try to make some room in the middle buffer */
 343         if (left_buf) {
 344                 btrfs_cow_block(trans, root, left_buf, parent_buf, pslot - 1,
 345                                 &left_buf);
 346                 left = btrfs_buffer_node(left_buf);
 347                 orig_slot += btrfs_header_nritems(&left->header);
 348                 wret = push_node_left(trans, root, left_buf, mid_buf);
 349                 if (wret < 0)
 350                         ret = wret;
 351         }
 352
 353         /*
 354          * then try to empty the right most buffer into the middle
 355          */
 356         if (right_buf) {
 357                 btrfs_cow_block(trans, root, right_buf, parent_buf, pslot + 1,
 358                                 &right_buf);
 359                 right = btrfs_buffer_node(right_buf);
 360                 wret = push_node_left(trans, root, mid_buf, right_buf);
 361                 if (wret < 0)
 362                         ret = wret;
 363                 if (btrfs_header_nritems(&right->header) == 0) {
 364                         u64 blocknr = bh_blocknr(right_buf);
 365                         clean_tree_block(trans, root, right_buf);
 366                         wait_on_buffer(right_buf);
 367                         btrfs_block_release(root, right_buf);
 368                         right_buf = NULL;
 369                         right = NULL;
 370                         wret = del_ptr(trans, root, path, level + 1, pslot +
 371                                        1);
 372                         if (wret)
 373                                 ret = wret;
 374                         wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
 375                         if (wret)
 376                                 ret = wret;
 377                 } else {
 378                         btrfs_memcpy(root, parent,
 379                                      &parent->ptrs[pslot + 1].key,
 380                                      &right->ptrs[0].key,
 381                                      sizeof(struct btrfs_disk_key));
 382                         btrfs_mark_buffer_dirty(parent_buf);
 383                 }
 384         }
 385         if (btrfs_header_nritems(&mid->header) == 1) {
 386                 /*
 387                  * we're not allowed to leave a node with one item in the
 388                  * tree during a delete.  A deletion from lower in the tree
 389                  * could try to delete the only pointer in this node.
 390                  * So, pull some keys from the left.
 391                  * There has to be a left pointer at this point because
 392                  * otherwise we would have pulled some pointers from the
 393                  * right
 394                  */
 395                 BUG_ON(!left_buf);
 396                 wret = balance_node_right(trans, root, mid_buf, left_buf);
 397                 if (wret < 0)
 398                         ret = wret;
 399                 BUG_ON(wret == 1);
 400         }
 401         if (btrfs_header_nritems(&mid->header) == 0) {
 402                 /* we've managed to empty the middle node, drop it */
 403                 u64 blocknr = bh_blocknr(mid_buf);
 404                 clean_tree_block(trans, root, mid_buf);
 405                 wait_on_buffer(mid_buf);
 406                 btrfs_block_release(root, mid_buf);
 407                 mid_buf = NULL;
 408                 mid = NULL;
 409                 wret = del_ptr(trans, root, path, level + 1, pslot);
 410                 if (wret)
 411                         ret = wret;
 412                 wret = btrfs_free_extent(trans, root, blocknr, 1, 1);
 413                 if (wret)
 414                         ret = wret;
 415         } else {
 416                 /* update the parent key to reflect our changes */
 417                 btrfs_memcpy(root, parent,
 418                              &parent->ptrs[pslot].key, &mid->ptrs[0].key,
 419                              sizeof(struct btrfs_disk_key));
 420                 btrfs_mark_buffer_dirty(parent_buf);
 421         }
 422
 423         /* update the path */
 424         if (left_buf) {
 425                 if (btrfs_header_nritems(&left->header) > orig_slot) {
 426                         get_bh(left_buf);
 427                         path->nodes[level] = left_buf;
 428                         path->slots[level + 1] -= 1;
 429                         path->slots[level] = orig_slot;
 430                         if (mid_buf)
 431                                 btrfs_block_release(root, mid_buf);
 432                 } else {
 433                         orig_slot -= btrfs_header_nritems(&left->header);
 434                         path->slots[level] = orig_slot;
 435                 }
 436         }
 437         /* double check we haven't messed things up */
 438         check_block(root, path, level);
 439         if (orig_ptr !=
 440             btrfs_node_blockptr(btrfs_buffer_node(path->nodes[level]),
 441                                 path->slots[level]))
 442                 BUG();
 443
 444         if (right_buf)
 445                 btrfs_block_release(root, right_buf);
 446         if (left_buf)
 447                 btrfs_block_release(root, left_buf);
 448         return ret;
 449 }
 450
 451 /* returns zero if the push worked, non-zero otherwise */
 452 static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
 453                                 struct btrfs_root *root,
 454                                 struct btrfs_path *path, int level)
 455 {
 456         struct buffer_head *right_buf;
 457         struct buffer_head *mid_buf;
 458         struct buffer_head *left_buf;
 459         struct buffer_head *parent_buf = NULL;
 460         struct btrfs_node *right = NULL;
 461         struct btrfs_node *mid;
 462         struct btrfs_node *left = NULL;
 463         struct btrfs_node *parent = NULL;
 464         int ret = 0;
 465         int wret;
 466         int pslot;
 467         int orig_slot = path->slots[level];
 468         u64 orig_ptr;
 469
 470         if (level == 0)
 471                 return 1;
 472
 473         mid_buf = path->nodes[level];
 474         mid = btrfs_buffer_node(mid_buf);
 475         orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 476
 477         if (level < BTRFS_MAX_LEVEL - 1)
 478                 parent_buf = path->nodes[level + 1];
 479         pslot = path->slots[level + 1];
 480
 481         if (!parent_buf)
 482                 return 1;
 483         parent = btrfs_buffer_node(parent_buf);
 484
 485         left_buf = read_node_slot(root, parent_buf, pslot - 1);
 486
 487         /* first, try to make some room in the middle buffer */
 488         if (left_buf) {
 489                 u32 left_nr;
 490                 left = btrfs_buffer_node(left_buf);
 491                 left_nr = btrfs_header_nritems(&left->header);
 492                 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
 493                         wret = 1;
 494                 } else {
 495                         btrfs_cow_block(trans, root, left_buf, parent_buf,
 496                                         pslot - 1, &left_buf);
 497                         left = btrfs_buffer_node(left_buf);
 498                         wret = push_node_left(trans, root, left_buf, mid_buf);
 499                 }
 500                 if (wret < 0)
 501                         ret = wret;
 502                 if (wret == 0) {
 503                         orig_slot += left_nr;
 504                         btrfs_memcpy(root, parent,
 505                                      &parent->ptrs[pslot].key,
 506                                      &mid->ptrs[0].key,
 507                                      sizeof(struct btrfs_disk_key));
 508                         btrfs_mark_buffer_dirty(parent_buf);
 509                         if (btrfs_header_nritems(&left->header) > orig_slot) {
 510                                 path->nodes[level] = left_buf;
 511                                 path->slots[level + 1] -= 1;
 512                                 path->slots[level] = orig_slot;
 513                                 btrfs_block_release(root, mid_buf);
 514                         } else {
 515                                 orig_slot -=
 516                                         btrfs_header_nritems(&left->header);
 517                                 path->slots[level] = orig_slot;
 518                                 btrfs_block_release(root, left_buf);
 519                         }
 520                         check_node(root, path, level);
 521                         return 0;
 522                 }
 523                 btrfs_block_release(root, left_buf);
 524         }
 525         right_buf = read_node_slot(root, parent_buf, pslot + 1);
 526
 527         /*
 528          * then try to empty the right most buffer into the middle
 529          */
 530         if (right_buf) {
 531                 u32 right_nr;
 532                 right = btrfs_buffer_node(right_buf);
 533                 right_nr = btrfs_header_nritems(&right->header);
 534                 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
 535                         wret = 1;
 536                 } else {
 537                         btrfs_cow_block(trans, root, right_buf,
 538                                         parent_buf, pslot + 1, &right_buf);
 539                         right = btrfs_buffer_node(right_buf);
 540                         wret = balance_node_right(trans, root,
 541                                                   right_buf, mid_buf);
 542                 }
 543                 if (wret < 0)
 544                         ret = wret;
 545                 if (wret == 0) {
 546                         btrfs_memcpy(root, parent,
 547                                      &parent->ptrs[pslot + 1].key,
 548                                      &right->ptrs[0].key,
 549                                      sizeof(struct btrfs_disk_key));
 550                         btrfs_mark_buffer_dirty(parent_buf);
 551                         if (btrfs_header_nritems(&mid->header) <= orig_slot) {
 552                                 path->nodes[level] = right_buf;
 553                                 path->slots[level + 1] += 1;
 554                                 path->slots[level] = orig_slot -
 555                                         btrfs_header_nritems(&mid->header);
 556                                 btrfs_block_release(root, mid_buf);
 557                         } else {
 558                                 btrfs_block_release(root, right_buf);
 559                         }
 560                         check_node(root, path, level);
 561                         return 0;
 562                 }
 563                 btrfs_block_release(root, right_buf);
 564         }
 565         check_node(root, path, level);
 566         return 1;
 567 }
 568
 569 /*
 570  * look for key in the tree.  path is filled in with nodes along the way
 571  * if key is found, we return zero and you can find the item in the leaf
 572  * level of the path (level 0)
 573  *
 574  * If the key isn't found, the path points to the slot where it should
 575  * be inserted, and 1 is returned.  If there are other errors during the
 576  * search a negative error number is returned.
 577  *
 578  * if ins_len > 0, nodes and leaves will be split as we walk down the
 579  * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
 580  * possible)
 581  */
 582 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
 583                       *root, struct btrfs_key *key, struct btrfs_path *p, int
 584                       ins_len, int cow)
 585 {
 586         struct buffer_head *b;
 587         struct buffer_head *cow_buf;
 588         struct btrfs_node *c;
 589         int slot;
 590         int ret;
 591         int level;
 592
 593         WARN_ON(p->nodes[0] != NULL);
 594         WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
 595 again:
 596         b = root->node;
 597         get_bh(b);
 598         while (b) {
 599                 c = btrfs_buffer_node(b);
 600                 level = btrfs_header_level(&c->header);
 601                 if (cow) {
 602                         int wret;
 603                         wret = btrfs_cow_block(trans, root, b,
 604                                                p->nodes[level + 1],
 605                                                p->slots[level + 1],
 606                                                &cow_buf);
 607                         b = cow_buf;
 608                         c = btrfs_buffer_node(b);
 609                 }
 610                 BUG_ON(!cow && ins_len);
 611                 if (level != btrfs_header_level(&c->header))
 612                         WARN_ON(1);
 613                 level = btrfs_header_level(&c->header);
 614                 p->nodes[level] = b;
 615                 ret = check_block(root, p, level);
 616                 if (ret)
 617                         return -1;
 618                 ret = bin_search(c, key, &slot);
 619                 if (!btrfs_is_leaf(c)) {
 620                         if (ret && slot > 0)
 621                                 slot -= 1;
 622                         p->slots[level] = slot;
 623                         if (ins_len > 0 && btrfs_header_nritems(&c->header) >=
 624                             BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
 625                                 int sret = split_node(trans, root, p, level);
 626                                 BUG_ON(sret > 0);
 627                                 if (sret)
 628                                         return sret;
 629                                 b = p->nodes[level];
 630                                 c = btrfs_buffer_node(b);
 631                                 slot = p->slots[level];
 632                         } else if (ins_len < 0) {
 633                                 int sret = balance_level(trans, root, p,
 634                                                          level);
 635                                 if (sret)
 636                                         return sret;
 637                                 b = p->nodes[level];
 638                                 if (!b)
 639                                         goto again;
 640                                 c = btrfs_buffer_node(b);
 641                                 slot = p->slots[level];
 642                                 BUG_ON(btrfs_header_nritems(&c->header) == 1);
 643                         }
 644                         b = read_tree_block(root, btrfs_node_blockptr(c, slot));
 645                 } else {
 646                         struct btrfs_leaf *l = (struct btrfs_leaf *)c;
 647                         p->slots[level] = slot;
 648                         if (ins_len > 0 && btrfs_leaf_free_space(root, l) <
 649                             sizeof(struct btrfs_item) + ins_len) {
 650                                 int sret = split_leaf(trans, root, key,
 651                                                       p, ins_len);
 652                                 BUG_ON(sret > 0);
 653                                 if (sret)
 654                                         return sret;
 655                         }
 656                         return ret;
 657                 }
 658         }
 659         return 1;
 660 }
 661
 662 /*
 663  * adjust the pointers going up the tree, starting at level
 664  * making sure the right key of each node is points to 'key'.
 665  * This is used after shifting pointers to the left, so it stops
 666  * fixing up pointers when a given leaf/node is not in slot 0 of the
 667  * higher levels
 668  *
 669  * If this fails to write a tree block, it returns -1, but continues
 670  * fixing up the blocks in ram so the tree is consistent.
 671  */
 672 static int fixup_low_keys(struct btrfs_trans_handle *trans, struct btrfs_root
 673                           *root, struct btrfs_path *path, struct btrfs_disk_key
 674                           *key, int level)
 675 {
 676         int i;
 677         int ret = 0;
 678         for (i = level; i < BTRFS_MAX_LEVEL; i++) {
 679                 struct btrfs_node *t;
 680                 int tslot = path->slots[i];
 681                 if (!path->nodes[i])
 682                         break;
 683                 t = btrfs_buffer_node(path->nodes[i]);
 684                 btrfs_memcpy(root, t, &t->ptrs[tslot].key, key, sizeof(*key));
 685                 btrfs_mark_buffer_dirty(path->nodes[i]);
 686                 if (tslot != 0)
 687                         break;
 688         }
 689         return ret;
 690 }
 691
 692 /*
 693  * try to push data from one node into the next node left in the
 694  * tree.
 695  *
 696  * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
 697  * error, and > 0 if there was no room in the left hand block.
 698  */
 699 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
 700                           *root, struct buffer_head *dst_buf, struct
 701                           buffer_head *src_buf)
 702 {
 703         struct btrfs_node *src = btrfs_buffer_node(src_buf);
 704         struct btrfs_node *dst = btrfs_buffer_node(dst_buf);
 705         int push_items = 0;
 706         int src_nritems;
 707         int dst_nritems;
 708         int ret = 0;
 709
 710         src_nritems = btrfs_header_nritems(&src->header);
 711         dst_nritems = btrfs_header_nritems(&dst->header);
 712         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
 713         if (push_items <= 0) {
 714                 return 1;
 715         }
 716
 717         if (src_nritems < push_items)
 718                 push_items = src_nritems;
 719
 720         btrfs_memcpy(root, dst, dst->ptrs + dst_nritems, src->ptrs,
 721                      push_items * sizeof(struct btrfs_key_ptr));
 722         if (push_items < src_nritems) {
 723                 btrfs_memmove(root, src, src->ptrs, src->ptrs + push_items,
 724                         (src_nritems - push_items) *
 725                         sizeof(struct btrfs_key_ptr));
 726         }
 727         btrfs_set_header_nritems(&src->header, src_nritems - push_items);
 728         btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
 729         btrfs_mark_buffer_dirty(src_buf);
 730         btrfs_mark_buffer_dirty(dst_buf);
 731         return ret;
 732 }
 733
 734 /*
 735  * try to push data from one node into the next node right in the
 736  * tree.
 737  *
 738  * returns 0 if some ptrs were pushed, < 0 if there was some horrible
 739  * error, and > 0 if there was no room in the right hand block.
 740  *
 741  * this will  only push up to 1/2 the contents of the left node over
 742  */
 743 static int balance_node_right(struct btrfs_trans_handle *trans, struct
 744                               btrfs_root *root, struct buffer_head *dst_buf,
 745                               struct buffer_head *src_buf)
 746 {
 747         struct btrfs_node *src = btrfs_buffer_node(src_buf);
 748         struct btrfs_node *dst = btrfs_buffer_node(dst_buf);
 749         int push_items = 0;
 750         int max_push;
 751         int src_nritems;
 752         int dst_nritems;
 753         int ret = 0;
 754
 755         src_nritems = btrfs_header_nritems(&src->header);
 756         dst_nritems = btrfs_header_nritems(&dst->header);
 757         push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
 758         if (push_items <= 0) {
 759                 return 1;
 760         }
 761
 762         max_push = src_nritems / 2 + 1;
 763         /* don't try to empty the node */
 764         if (max_push > src_nritems)
 765                 return 1;
 766         if (max_push < push_items)
 767                 push_items = max_push;
 768
 769         btrfs_memmove(root, dst, dst->ptrs + push_items, dst->ptrs,
 770                       dst_nritems * sizeof(struct btrfs_key_ptr));
 771
 772         btrfs_memcpy(root, dst, dst->ptrs,
 773                      src->ptrs + src_nritems - push_items,
 774                      push_items * sizeof(struct btrfs_key_ptr));
 775
 776         btrfs_set_header_nritems(&src->header, src_nritems - push_items);
 777         btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
 778
 779         btrfs_mark_buffer_dirty(src_buf);
 780         btrfs_mark_buffer_dirty(dst_buf);
 781         return ret;
 782 }
 783
 784 /*
 785  * helper function to insert a new root level in the tree.
 786  * A new node is allocated, and a single item is inserted to
 787  * point to the existing root
 788  *
 789  * returns zero on success or < 0 on failure.
 790  */
 791 static int insert_new_root(struct btrfs_trans_handle *trans, struct btrfs_root
 792                            *root, struct btrfs_path *path, int level)
 793 {
 794         struct buffer_head *t;
 795         struct btrfs_node *lower;
 796         struct btrfs_node *c;
 797         struct btrfs_disk_key *lower_key;
 798
 799         BUG_ON(path->nodes[level]);
 800         BUG_ON(path->nodes[level-1] != root->node);
 801
 802         t = btrfs_alloc_free_block(trans, root);
 803         c = btrfs_buffer_node(t);
 804         memset(c, 0, root->blocksize);
 805         btrfs_set_header_nritems(&c->header, 1);
 806         btrfs_set_header_level(&c->header, level);
 807         btrfs_set_header_blocknr(&c->header, bh_blocknr(t));
 808         btrfs_set_header_generation(&c->header, trans->transid);
 809         lower = btrfs_buffer_node(path->nodes[level-1]);
 810         memcpy(c->header.fsid, root->fs_info->disk_super->fsid,
 811                sizeof(c->header.fsid));
 812         if (btrfs_is_leaf(lower))
 813                 lower_key = &((struct btrfs_leaf *)lower)->items[0].key;
 814         else
 815                 lower_key = &lower->ptrs[0].key;
 816         btrfs_memcpy(root, c, &c->ptrs[0].key, lower_key,
 817                      sizeof(struct btrfs_disk_key));
 818         btrfs_set_node_blockptr(c, 0, bh_blocknr(path->nodes[level - 1]));
 819
 820         btrfs_mark_buffer_dirty(t);
 821
 822         /* the super has an extra ref to root->node */
 823         btrfs_block_release(root, root->node);
 824         root->node = t;
 825         get_bh(t);
 826         path->nodes[level] = t;
 827         path->slots[level] = 0;
 828         return 0;
 829 }
 830
 831 /*
 832  * worker function to insert a single pointer in a node.
 833  * the node should have enough room for the pointer already
 834  *
 835  * slot and level indicate where you want the key to go, and
 836  * blocknr is the block the key points to.
 837  *
 838  * returns zero on success and < 0 on any error
 839  */
 840 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
 841                       *root, struct btrfs_path *path, struct btrfs_disk_key
 842                       *key, u64 blocknr, int slot, int level)
 843 {
 844         struct btrfs_node *lower;
 845         int nritems;
 846
 847         BUG_ON(!path->nodes[level]);
 848         lower = btrfs_buffer_node(path->nodes[level]);
 849         nritems = btrfs_header_nritems(&lower->header);
 850         if (slot > nritems)
 851                 BUG();
 852         if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
 853                 BUG();
 854         if (slot != nritems) {
 855                 btrfs_memmove(root, lower, lower->ptrs + slot + 1,
 856                               lower->ptrs + slot,
 857                               (nritems - slot) * sizeof(struct btrfs_key_ptr));
 858         }
 859         btrfs_memcpy(root, lower, &lower->ptrs[slot].key,
 860                      key, sizeof(struct btrfs_disk_key));
 861         btrfs_set_node_blockptr(lower, slot, blocknr);
 862         btrfs_set_header_nritems(&lower->header, nritems + 1);
 863         btrfs_mark_buffer_dirty(path->nodes[level]);
 864         return 0;
 865 }
 866
 867 /*
 868  * split the node at the specified level in path in two.
 869  * The path is corrected to point to the appropriate node after the split
 870  *
 871  * Before splitting this tries to make some room in the node by pushing
 872  * left and right, if either one works, it returns right away.
 873  *
 874  * returns 0 on success and < 0 on failure
 875  */
 876 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
 877                       *root, struct btrfs_path *path, int level)
 878 {
 879         struct buffer_head *t;
 880         struct btrfs_node *c;
 881         struct buffer_head *split_buffer;
 882         struct btrfs_node *split;
 883         int mid;
 884         int ret;
 885         int wret;
 886         u32 c_nritems;
 887
 888         t = path->nodes[level];
 889         c = btrfs_buffer_node(t);
 890         if (t == root->node) {
 891                 /* trying to split the root, lets make a new one */
 892                 ret = insert_new_root(trans, root, path, level + 1);
 893                 if (ret)
 894                         return ret;
 895         } else {
 896                 ret = push_nodes_for_insert(trans, root, path, level);
 897                 t = path->nodes[level];
 898                 c = btrfs_buffer_node(t);
 899                 if (!ret &&
 900                     btrfs_header_nritems(&c->header) <
 901                     BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
 902                         return 0;
 903         }
 904
 905         c_nritems = btrfs_header_nritems(&c->header);
 906         split_buffer = btrfs_alloc_free_block(trans, root);
 907         split = btrfs_buffer_node(split_buffer);
 908         btrfs_set_header_flags(&split->header, btrfs_header_flags(&c->header));
 909         btrfs_set_header_level(&split->header, btrfs_header_level(&c->header));
 910         btrfs_set_header_blocknr(&split->header, bh_blocknr(split_buffer));
 911         btrfs_set_header_generation(&split->header, trans->transid);
 912         memcpy(split->header.fsid, root->fs_info->disk_super->fsid,
 913                sizeof(split->header.fsid));
 914         mid = (c_nritems + 1) / 2;
 915         btrfs_memcpy(root, split, split->ptrs, c->ptrs + mid,
 916                      (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
 917         btrfs_set_header_nritems(&split->header, c_nritems - mid);
 918         btrfs_set_header_nritems(&c->header, mid);
 919         ret = 0;
 920
 921         btrfs_mark_buffer_dirty(t);
 922         btrfs_mark_buffer_dirty(split_buffer);
 923         wret = insert_ptr(trans, root, path, &split->ptrs[0].key,
 924                           bh_blocknr(split_buffer), path->slots[level + 1] + 1,
 925                           level + 1);
 926         if (wret)
 927                 ret = wret;
 928
 929         if (path->slots[level] >= mid) {
 930                 path->slots[level] -= mid;
 931                 btrfs_block_release(root, t);
 932                 path->nodes[level] = split_buffer;
 933                 path->slots[level + 1] += 1;
 934         } else {
 935                 btrfs_block_release(root, split_buffer);
 936         }
 937         return ret;
 938 }
 939
 940 /*
 941  * how many bytes are required to store the items in a leaf.  start
 942  * and nr indicate which items in the leaf to check.  This totals up the
 943  * space used both by the item structs and the item data
 944  */
 945 static int leaf_space_used(struct btrfs_leaf *l, int start, int nr)
 946 {
 947         int data_len;
 948         int nritems = btrfs_header_nritems(&l->header);
 949         int end = min(nritems, start + nr) - 1;
 950
 951         if (!nr)
 952                 return 0;
 953         data_len = btrfs_item_end(l->items + start);
 954         data_len = data_len - btrfs_item_offset(l->items + end);
 955         data_len += sizeof(struct btrfs_item) * nr;
 956         WARN_ON(data_len < 0);
 957         return data_len;
 958 }
 959
 960 /*
 961  * The space between the end of the leaf items and
 962  * the start of the leaf data.  IOW, how much room
 963  * the leaf has left for both items and data
 964  */
 965 int btrfs_leaf_free_space(struct btrfs_root *root, struct btrfs_leaf *leaf)
 966 {
 967         int nritems = btrfs_header_nritems(&leaf->header);
 968         return BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
 969 }
 970
 971 /*
 972  * push some data in the path leaf to the right, trying to free up at
 973  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
 974  *
 975  * returns 1 if the push failed because the other node didn't have enough
 976  * room, 0 if everything worked out and < 0 if there were major errors.
 977  */
 978 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
 979                            *root, struct btrfs_path *path, int data_size)
 980 {
 981         struct buffer_head *left_buf = path->nodes[0];
 982         struct btrfs_leaf *left = btrfs_buffer_leaf(left_buf);
 983         struct btrfs_leaf *right;
 984         struct buffer_head *right_buf;
 985         struct buffer_head *upper;
 986         struct btrfs_node *upper_node;
 987         int slot;
 988         int i;
 989         int free_space;
 990         int push_space = 0;
 991         int push_items = 0;
 992         struct btrfs_item *item;
 993         u32 left_nritems;
 994         u32 right_nritems;
 995
 996         slot = path->slots[1];
 997         if (!path->nodes[1]) {
 998                 return 1;
 999         }
1000         upper = path->nodes[1];
1001         upper_node = btrfs_buffer_node(upper);
1002         if (slot >= btrfs_header_nritems(&upper_node->header) - 1) {
1003                 return 1;
1004         }
1005         right_buf = read_tree_block(root,
1006                     btrfs_node_blockptr(btrfs_buffer_node(upper), slot + 1));
1007         right = btrfs_buffer_leaf(right_buf);
1008         free_space = btrfs_leaf_free_space(root, right);
1009         if (free_space < data_size + sizeof(struct btrfs_item)) {
1010                 btrfs_block_release(root, right_buf);
1011                 return 1;
1012         }
1013         /* cow and double check */
1014         btrfs_cow_block(trans, root, right_buf, upper, slot + 1, &right_buf);
1015         right = btrfs_buffer_leaf(right_buf);
1016         free_space = btrfs_leaf_free_space(root, right);
1017         if (free_space < data_size + sizeof(struct btrfs_item)) {
1018                 btrfs_block_release(root, right_buf);
1019                 return 1;
1020         }
1021
1022         left_nritems = btrfs_header_nritems(&left->header);
1023         if (left_nritems == 0) {
1024                 btrfs_block_release(root, right_buf);
1025                 return 1;
1026         }
1027         for (i = left_nritems - 1; i >= 1; i--) {
1028                 item = left->items + i;
1029                 if (path->slots[0] == i)
1030                         push_space += data_size + sizeof(*item);
1031                 if (btrfs_item_size(item) + sizeof(*item) + push_space >
1032                     free_space)
1033                         break;
1034                 push_items++;
1035                 push_space += btrfs_item_size(item) + sizeof(*item);
1036         }
1037         if (push_items == 0) {
1038                 btrfs_block_release(root, right_buf);
1039                 return 1;
1040         }
1041         if (push_items == left_nritems)
1042                 WARN_ON(1);
1043         right_nritems = btrfs_header_nritems(&right->header);
1044         /* push left to right */
1045         push_space = btrfs_item_end(left->items + left_nritems - push_items);
1046         push_space -= leaf_data_end(root, left);
1047         /* make room in the right data area */
1048         btrfs_memmove(root, right, btrfs_leaf_data(right) +
1049                       leaf_data_end(root, right) - push_space,
1050                       btrfs_leaf_data(right) +
1051                       leaf_data_end(root, right), BTRFS_LEAF_DATA_SIZE(root) -
1052                       leaf_data_end(root, right));
1053         /* copy from the left data area */
1054         btrfs_memcpy(root, right, btrfs_leaf_data(right) +
1055                      BTRFS_LEAF_DATA_SIZE(root) - push_space,
1056                      btrfs_leaf_data(left) + leaf_data_end(root, left),
1057                      push_space);
1058         btrfs_memmove(root, right, right->items + push_items, right->items,
1059                 right_nritems * sizeof(struct btrfs_item));
1060         /* copy the items from left to right */
1061         btrfs_memcpy(root, right, right->items, left->items +
1062                      left_nritems - push_items,
1063                      push_items * sizeof(struct btrfs_item));
1064
1065         /* update the item pointers */
1066         right_nritems += push_items;
1067         btrfs_set_header_nritems(&right->header, right_nritems);
1068         push_space = BTRFS_LEAF_DATA_SIZE(root);
1069         for (i = 0; i < right_nritems; i++) {
1070                 btrfs_set_item_offset(right->items + i, push_space -
1071                                       btrfs_item_size(right->items + i));
1072                 push_space = btrfs_item_offset(right->items + i);
1073         }
1074         left_nritems -= push_items;
1075         btrfs_set_header_nritems(&left->header, left_nritems);
1076
1077         btrfs_mark_buffer_dirty(left_buf);
1078         btrfs_mark_buffer_dirty(right_buf);
1079
1080         btrfs_memcpy(root, upper_node, &upper_node->ptrs[slot + 1].key,
1081                 &right->items[0].key, sizeof(struct btrfs_disk_key));
1082         btrfs_mark_buffer_dirty(upper);
1083
1084         /* then fixup the leaf pointer in the path */
1085         if (path->slots[0] >= left_nritems) {
1086                 path->slots[0] -= left_nritems;
1087                 btrfs_block_release(root, path->nodes[0]);
1088                 path->nodes[0] = right_buf;
1089                 path->slots[1] += 1;
1090         } else {
1091                 btrfs_block_release(root, right_buf);
1092         }
1093         return 0;
1094 }
1095 /*
1096  * push some data in the path leaf to the left, trying to free up at
1097  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
1098  */
1099 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1100                           *root, struct btrfs_path *path, int data_size)
1101 {
1102         struct buffer_head *right_buf = path->nodes[0];
1103         struct btrfs_leaf *right = btrfs_buffer_leaf(right_buf);
1104         struct buffer_head *t;
1105         struct btrfs_leaf *left;
1106         int slot;
1107         int i;
1108         int free_space;
1109         int push_space = 0;
1110         int push_items = 0;
1111         struct btrfs_item *item;
1112         u32 old_left_nritems;
1113         int ret = 0;
1114         int wret;
1115
1116         slot = path->slots[1];
1117         if (slot == 0) {
1118                 return 1;
1119         }
1120         if (!path->nodes[1]) {
1121                 return 1;
1122         }
1123         t = read_tree_block(root,
1124             btrfs_node_blockptr(btrfs_buffer_node(path->nodes[1]), slot - 1));
1125         left = btrfs_buffer_leaf(t);
1126         free_space = btrfs_leaf_free_space(root, left);
1127         if (free_space < data_size + sizeof(struct btrfs_item)) {
1128                 btrfs_block_release(root, t);
1129                 return 1;
1130         }
1131
1132         /* cow and double check */
1133         btrfs_cow_block(trans, root, t, path->nodes[1], slot - 1, &t);
1134         left = btrfs_buffer_leaf(t);
1135         free_space = btrfs_leaf_free_space(root, left);
1136         if (free_space < data_size + sizeof(struct btrfs_item)) {
1137                 btrfs_block_release(root, t);
1138                 return 1;
1139         }
1140
1141         if (btrfs_header_nritems(&right->header) == 0) {
1142                 btrfs_block_release(root, t);
1143                 return 1;
1144         }
1145
1146         for (i = 0; i < btrfs_header_nritems(&right->header) - 1; i++) {
1147                 item = right->items + i;
1148                 if (path->slots[0] == i)
1149                         push_space += data_size + sizeof(*item);
1150                 if (btrfs_item_size(item) + sizeof(*item) + push_space >
1151                     free_space)
1152                         break;
1153                 push_items++;
1154                 push_space += btrfs_item_size(item) + sizeof(*item);
1155         }
1156         if (push_items == 0) {
1157                 btrfs_block_release(root, t);
1158                 return 1;
1159         }
1160         if (push_items == btrfs_header_nritems(&right->header))
1161                 WARN_ON(1);
1162         /* push data from right to left */
1163         btrfs_memcpy(root, left, left->items +
1164                      btrfs_header_nritems(&left->header),
1165                      right->items, push_items * sizeof(struct btrfs_item));
1166         push_space = BTRFS_LEAF_DATA_SIZE(root) -
1167                      btrfs_item_offset(right->items + push_items -1);
1168         btrfs_memcpy(root, left, btrfs_leaf_data(left) +
1169                      leaf_data_end(root, left) - push_space,
1170                      btrfs_leaf_data(right) +
1171                      btrfs_item_offset(right->items + push_items - 1),
1172                      push_space);
1173         old_left_nritems = btrfs_header_nritems(&left->header);
1174         BUG_ON(old_left_nritems < 0);
1175
1176         for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1177                 u32 ioff = btrfs_item_offset(left->items + i);
1178                 btrfs_set_item_offset(left->items + i, ioff -
1179                                      (BTRFS_LEAF_DATA_SIZE(root) -
1180                                       btrfs_item_offset(left->items +
1181                                                         old_left_nritems - 1)));
1182         }
1183         btrfs_set_header_nritems(&left->header, old_left_nritems + push_items);
1184
1185         /* fixup right node */
1186         push_space = btrfs_item_offset(right->items + push_items - 1) -
1187                      leaf_data_end(root, right);
1188         btrfs_memmove(root, right, btrfs_leaf_data(right) +
1189                       BTRFS_LEAF_DATA_SIZE(root) - push_space,
1190                       btrfs_leaf_data(right) +
1191                       leaf_data_end(root, right), push_space);
1192         btrfs_memmove(root, right, right->items, right->items + push_items,
1193                 (btrfs_header_nritems(&right->header) - push_items) *
1194                 sizeof(struct btrfs_item));
1195         btrfs_set_header_nritems(&right->header,
1196                                  btrfs_header_nritems(&right->header) -
1197                                  push_items);
1198         push_space = BTRFS_LEAF_DATA_SIZE(root);
1199
1200         for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1201                 btrfs_set_item_offset(right->items + i, push_space -
1202                                       btrfs_item_size(right->items + i));
1203                 push_space = btrfs_item_offset(right->items + i);
1204         }
1205
1206         btrfs_mark_buffer_dirty(t);
1207         btrfs_mark_buffer_dirty(right_buf);
1208         wret = fixup_low_keys(trans, root, path, &right->items[0].key, 1);
1209         if (wret)
1210                 ret = wret;
1211
1212         /* then fixup the leaf pointer in the path */
1213         if (path->slots[0] < push_items) {
1214                 path->slots[0] += old_left_nritems;
1215                 btrfs_block_release(root, path->nodes[0]);
1216                 path->nodes[0] = t;
1217                 path->slots[1] -= 1;
1218         } else {
1219                 btrfs_block_release(root, t);
1220                 path->slots[0] -= push_items;
1221         }
1222         BUG_ON(path->slots[0] < 0);
1223         return ret;
1224 }
1225
1226 /*
1227  * split the path's leaf in two, making sure there is at least data_size
1228  * available for the resulting leaf level of the path.
1229  *
1230  * returns 0 if all went well and < 0 on failure.
1231  */
1232 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1233                       *root, struct btrfs_key *ins_key,
1234                       struct btrfs_path *path, int data_size)
1235 {
1236         struct buffer_head *l_buf;
1237         struct btrfs_leaf *l;
1238         u32 nritems;
1239         int mid;
1240         int slot;
1241         struct btrfs_leaf *right;
1242         struct buffer_head *right_buffer;
1243         int space_needed = data_size + sizeof(struct btrfs_item);
1244         int data_copy_size;
1245         int rt_data_off;
1246         int i;
1247         int ret = 0;
1248         int wret;
1249         int double_split = 0;
1250         struct btrfs_disk_key disk_key;
1251
1252         /* first try to make some room by pushing left and right */
1253         wret = push_leaf_left(trans, root, path, data_size);
1254         if (wret < 0)
1255                 return wret;
1256         if (wret) {
1257                 wret = push_leaf_right(trans, root, path, data_size);
1258                 if (wret < 0)
1259                         return wret;
1260         }
1261         l_buf = path->nodes[0];
1262         l = btrfs_buffer_leaf(l_buf);
1263
1264         /* did the pushes work? */
1265         if (btrfs_leaf_free_space(root, l) >=
1266             sizeof(struct btrfs_item) + data_size)
1267                 return 0;
1268
1269         if (!path->nodes[1]) {
1270                 ret = insert_new_root(trans, root, path, 1);
1271                 if (ret)
1272                         return ret;
1273         }
1274         slot = path->slots[0];
1275         nritems = btrfs_header_nritems(&l->header);
1276         mid = (nritems + 1)/ 2;
1277         right_buffer = btrfs_alloc_free_block(trans, root);
1278         BUG_ON(!right_buffer);
1279         right = btrfs_buffer_leaf(right_buffer);
1280         memset(&right->header, 0, sizeof(right->header));
1281         btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer));
1282         btrfs_set_header_generation(&right->header, trans->transid);
1283         btrfs_set_header_level(&right->header, 0);
1284         memcpy(right->header.fsid, root->fs_info->disk_super->fsid,
1285                sizeof(right->header.fsid));
1286         if (mid <= slot) {
1287                 if (nritems == 1 ||
1288                     leaf_space_used(l, mid, nritems - mid) + space_needed >
1289                         BTRFS_LEAF_DATA_SIZE(root)) {
1290                         if (slot >= nritems) {
1291                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1292                                 btrfs_set_header_nritems(&right->header, 0);
1293                                 wret = insert_ptr(trans, root, path,
1294                                                   &disk_key,
1295                                                   bh_blocknr(right_buffer),
1296                                                   path->slots[1] + 1, 1);
1297                                 if (wret)
1298                                         ret = wret;
1299                                 btrfs_block_release(root, path->nodes[0]);
1300                                 path->nodes[0] = right_buffer;
1301                                 path->slots[0] = 0;
1302                                 path->slots[1] += 1;
1303                                 return ret;
1304                         }
1305                         mid = slot;
1306                         double_split = 1;
1307                 }
1308         } else {
1309                 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1310                         BTRFS_LEAF_DATA_SIZE(root)) {
1311                         if (slot == 0) {
1312                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1313                                 btrfs_set_header_nritems(&right->header, 0);
1314                                 wret = insert_ptr(trans, root, path,
1315                                                   &disk_key,
1316                                                   bh_blocknr(right_buffer),
1317                                                   path->slots[1] - 1, 1);
1318                                 if (wret)
1319                                         ret = wret;
1320                                 btrfs_block_release(root, path->nodes[0]);
1321                                 path->nodes[0] = right_buffer;
1322                                 path->slots[0] = 0;
1323                                 path->slots[1] -= 1;
1324                                 if (path->slots[1] == 0) {
1325                                         wret = fixup_low_keys(trans, root,
1326                                                    path, &disk_key, 1);
1327                                         if (wret)
1328                                                 ret = wret;
1329                                 }
1330                                 return ret;
1331                         }
1332                         mid = slot;
1333                         double_split = 1;
1334                 }
1335         }
1336         btrfs_set_header_nritems(&right->header, nritems - mid);
1337         data_copy_size = btrfs_item_end(l->items + mid) -
1338                          leaf_data_end(root, l);
1339         btrfs_memcpy(root, right, right->items, l->items + mid,
1340                      (nritems - mid) * sizeof(struct btrfs_item));
1341         btrfs_memcpy(root, right,
1342                      btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1343                      data_copy_size, btrfs_leaf_data(l) +
1344                      leaf_data_end(root, l), data_copy_size);
1345         rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1346                       btrfs_item_end(l->items + mid);
1347
1348         for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
1349                 u32 ioff = btrfs_item_offset(right->items + i);
1350                 btrfs_set_item_offset(right->items + i, ioff + rt_data_off);
1351         }
1352
1353         btrfs_set_header_nritems(&l->header, mid);
1354         ret = 0;
1355         wret = insert_ptr(trans, root, path, &right->items[0].key,
1356                           bh_blocknr(right_buffer), path->slots[1] + 1, 1);
1357         if (wret)
1358                 ret = wret;
1359         btrfs_mark_buffer_dirty(right_buffer);
1360         btrfs_mark_buffer_dirty(l_buf);
1361         BUG_ON(path->slots[0] != slot);
1362         if (mid <= slot) {
1363                 btrfs_block_release(root, path->nodes[0]);
1364                 path->nodes[0] = right_buffer;
1365                 path->slots[0] -= mid;
1366                 path->slots[1] += 1;
1367         } else
1368                 btrfs_block_release(root, right_buffer);
1369         BUG_ON(path->slots[0] < 0);
1370
1371         if (!double_split)
1372                 return ret;
1373         right_buffer = btrfs_alloc_free_block(trans, root);
1374         BUG_ON(!right_buffer);
1375         right = btrfs_buffer_leaf(right_buffer);
1376         memset(&right->header, 0, sizeof(right->header));
1377         btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer));
1378         btrfs_set_header_generation(&right->header, trans->transid);
1379         btrfs_set_header_level(&right->header, 0);
1380         memcpy(right->header.fsid, root->fs_info->disk_super->fsid,
1381                sizeof(right->header.fsid));
1382         btrfs_cpu_key_to_disk(&disk_key, ins_key);
1383         btrfs_set_header_nritems(&right->header, 0);
1384         wret = insert_ptr(trans, root, path,
1385                           &disk_key,
1386                           bh_blocknr(right_buffer),
1387                           path->slots[1], 1);
1388         if (wret)
1389                 ret = wret;
1390         if (path->slots[1] == 0) {
1391                 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1392                 if (wret)
1393                         ret = wret;
1394         }
1395         btrfs_block_release(root, path->nodes[0]);
1396         path->nodes[0] = right_buffer;
1397         path->slots[0] = 0;
1398         check_node(root, path, 1);
1399         check_leaf(root, path, 0);
1400         return ret;
1401 }
1402
1403 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
1404                         struct btrfs_root *root,
1405                         struct btrfs_path *path,
1406                         u32 new_size)
1407 {
1408         int ret = 0;
1409         int slot;
1410         int slot_orig;
1411         struct btrfs_leaf *leaf;
1412         struct buffer_head *leaf_buf;
1413         u32 nritems;
1414         unsigned int data_end;
1415         unsigned int old_data_start;
1416         unsigned int old_size;
1417         unsigned int size_diff;
1418         int i;
1419
1420         slot_orig = path->slots[0];
1421         leaf_buf = path->nodes[0];
1422         leaf = btrfs_buffer_leaf(leaf_buf);
1423
1424         nritems = btrfs_header_nritems(&leaf->header);
1425         data_end = leaf_data_end(root, leaf);
1426
1427         slot = path->slots[0];
1428         old_data_start = btrfs_item_offset(leaf->items + slot);
1429         old_size = btrfs_item_size(leaf->items + slot);
1430         BUG_ON(old_size <= new_size);
1431         size_diff = old_size - new_size;
1432
1433         BUG_ON(slot < 0);
1434         BUG_ON(slot >= nritems);
1435
1436         /*
1437          * item0..itemN ... dataN.offset..dataN.size .. data0.size
1438          */
1439         /* first correct the data pointers */
1440         for (i = slot; i < nritems; i++) {
1441                 u32 ioff = btrfs_item_offset(leaf->items + i);
1442                 btrfs_set_item_offset(leaf->items + i,
1443                                       ioff + size_diff);
1444         }
1445         /* shift the data */
1446         btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1447                       data_end + size_diff, btrfs_leaf_data(leaf) +
1448                       data_end, old_data_start + new_size - data_end);
1449         btrfs_set_item_size(leaf->items + slot, new_size);
1450         btrfs_mark_buffer_dirty(leaf_buf);
1451
1452         ret = 0;
1453         if (btrfs_leaf_free_space(root, leaf) < 0)
1454                 BUG();
1455         check_leaf(root, path, 0);
1456         return ret;
1457 }
1458
1459 int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
1460                       *root, struct btrfs_path *path, u32 data_size)
1461 {
1462         int ret = 0;
1463         int slot;
1464         int slot_orig;
1465         struct btrfs_leaf *leaf;
1466         struct buffer_head *leaf_buf;
1467         u32 nritems;
1468         unsigned int data_end;
1469         unsigned int old_data;
1470         unsigned int old_size;
1471         int i;
1472
1473         slot_orig = path->slots[0];
1474         leaf_buf = path->nodes[0];
1475         leaf = btrfs_buffer_leaf(leaf_buf);
1476
1477         nritems = btrfs_header_nritems(&leaf->header);
1478         data_end = leaf_data_end(root, leaf);
1479
1480         if (btrfs_leaf_free_space(root, leaf) < data_size)
1481                 BUG();
1482         slot = path->slots[0];
1483         old_data = btrfs_item_end(leaf->items + slot);
1484
1485         BUG_ON(slot < 0);
1486         BUG_ON(slot >= nritems);
1487
1488         /*
1489          * item0..itemN ... dataN.offset..dataN.size .. data0.size
1490          */
1491         /* first correct the data pointers */
1492         for (i = slot; i < nritems; i++) {
1493                 u32 ioff = btrfs_item_offset(leaf->items + i);
1494                 btrfs_set_item_offset(leaf->items + i,
1495                                       ioff - data_size);
1496         }
1497         /* shift the data */
1498         btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1499                       data_end - data_size, btrfs_leaf_data(leaf) +
1500                       data_end, old_data - data_end);
1501         data_end = old_data;
1502         old_size = btrfs_item_size(leaf->items + slot);
1503         btrfs_set_item_size(leaf->items + slot, old_size + data_size);
1504         btrfs_mark_buffer_dirty(leaf_buf);
1505
1506         ret = 0;
1507         if (btrfs_leaf_free_space(root, leaf) < 0)
1508                 BUG();
1509         check_leaf(root, path, 0);
1510         return ret;
1511 }
1512
1513 /*
1514  * Given a key and some data, insert an item into the tree.
1515  * This does all the path init required, making room in the tree if needed.
1516  */
1517 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans, struct btrfs_root
1518                             *root, struct btrfs_path *path, struct btrfs_key
1519                             *cpu_key, u32 data_size)
1520 {
1521         int ret = 0;
1522         int slot;
1523         int slot_orig;
1524         struct btrfs_leaf *leaf;
1525         struct buffer_head *leaf_buf;
1526         u32 nritems;
1527         unsigned int data_end;
1528         struct btrfs_disk_key disk_key;
1529
1530         btrfs_cpu_key_to_disk(&disk_key, cpu_key);
1531
1532         /* create a root if there isn't one */
1533         if (!root->node)
1534                 BUG();
1535         ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
1536         if (ret == 0) {
1537                 return -EEXIST;
1538         }
1539         if (ret < 0)
1540                 goto out;
1541
1542         slot_orig = path->slots[0];
1543         leaf_buf = path->nodes[0];
1544         leaf = btrfs_buffer_leaf(leaf_buf);
1545
1546         nritems = btrfs_header_nritems(&leaf->header);
1547         data_end = leaf_data_end(root, leaf);
1548
1549         if (btrfs_leaf_free_space(root, leaf) <
1550             sizeof(struct btrfs_item) + data_size) {
1551                 BUG();
1552         }
1553         slot = path->slots[0];
1554         BUG_ON(slot < 0);
1555         if (slot != nritems) {
1556                 int i;
1557                 unsigned int old_data = btrfs_item_end(leaf->items + slot);
1558
1559                 /*
1560                  * item0..itemN ... dataN.offset..dataN.size .. data0.size
1561                  */
1562                 /* first correct the data pointers */
1563                 for (i = slot; i < nritems; i++) {
1564                         u32 ioff = btrfs_item_offset(leaf->items + i);
1565                         btrfs_set_item_offset(leaf->items + i,
1566                                               ioff - data_size);
1567                 }
1568
1569                 /* shift the items */
1570                 btrfs_memmove(root, leaf, leaf->items + slot + 1,
1571                               leaf->items + slot,
1572                               (nritems - slot) * sizeof(struct btrfs_item));
1573
1574                 /* shift the data */
1575                 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1576                               data_end - data_size, btrfs_leaf_data(leaf) +
1577                               data_end, old_data - data_end);
1578                 data_end = old_data;
1579         }
1580         /* setup the item for the new data */
1581         btrfs_memcpy(root, leaf, &leaf->items[slot].key, &disk_key,
1582                      sizeof(struct btrfs_disk_key));
1583         btrfs_set_item_offset(leaf->items + slot, data_end - data_size);
1584         btrfs_set_item_size(leaf->items + slot, data_size);
1585         btrfs_set_header_nritems(&leaf->header, nritems + 1);
1586         btrfs_mark_buffer_dirty(leaf_buf);
1587
1588         ret = 0;
1589         if (slot == 0)
1590                 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
1591
1592         if (btrfs_leaf_free_space(root, leaf) < 0)
1593                 BUG();
1594         check_leaf(root, path, 0);
1595 out:
1596         return ret;
1597 }
1598
1599 /*
1600  * Given a key and some data, insert an item into the tree.
1601  * This does all the path init required, making room in the tree if needed.
1602  */
1603 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
1604                       *root, struct btrfs_key *cpu_key, void *data, u32
1605                       data_size)
1606 {
1607         int ret = 0;
1608         struct btrfs_path *path;
1609         u8 *ptr;
1610
1611         path = btrfs_alloc_path();
1612         BUG_ON(!path);
1613         btrfs_init_path(path);
1614         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
1615         if (!ret) {
1616                 ptr = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
1617                                      path->slots[0], u8);
1618                 btrfs_memcpy(root, path->nodes[0]->b_data,
1619                              ptr, data, data_size);
1620                 btrfs_mark_buffer_dirty(path->nodes[0]);
1621         }
1622         btrfs_release_path(root, path);
1623         btrfs_free_path(path);
1624         return ret;
1625 }
1626
1627 /*
1628  * delete the pointer from a given node.
1629  *
1630  * If the delete empties a node, the node is removed from the tree,
1631  * continuing all the way the root if required.  The root is converted into
1632  * a leaf if all the nodes are emptied.
1633  */
1634 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1635                    struct btrfs_path *path, int level, int slot)
1636 {
1637         struct btrfs_node *node;
1638         struct buffer_head *parent = path->nodes[level];
1639         u32 nritems;
1640         int ret = 0;
1641         int wret;
1642
1643         node = btrfs_buffer_node(parent);
1644         nritems = btrfs_header_nritems(&node->header);
1645         if (slot != nritems -1) {
1646                 btrfs_memmove(root, node, node->ptrs + slot,
1647                               node->ptrs + slot + 1,
1648                               sizeof(struct btrfs_key_ptr) *
1649                               (nritems - slot - 1));
1650         }
1651         nritems--;
1652         btrfs_set_header_nritems(&node->header, nritems);
1653         if (nritems == 0 && parent == root->node) {
1654                 struct btrfs_header *header = btrfs_buffer_header(root->node);
1655                 BUG_ON(btrfs_header_level(header) != 1);
1656                 /* just turn the root into a leaf and break */
1657                 btrfs_set_header_level(header, 0);
1658         } else if (slot == 0) {
1659                 wret = fixup_low_keys(trans, root, path, &node->ptrs[0].key,
1660                                       level + 1);
1661                 if (wret)
1662                         ret = wret;
1663         }
1664         btrfs_mark_buffer_dirty(parent);
1665         return ret;
1666 }
1667
1668 /*
1669  * delete the item at the leaf level in path.  If that empties
1670  * the leaf, remove it from the tree
1671  */
1672 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1673                    struct btrfs_path *path)
1674 {
1675         int slot;
1676         struct btrfs_leaf *leaf;
1677         struct buffer_head *leaf_buf;
1678         int doff;
1679         int dsize;
1680         int ret = 0;
1681         int wret;
1682         u32 nritems;
1683
1684         leaf_buf = path->nodes[0];
1685         leaf = btrfs_buffer_leaf(leaf_buf);
1686         slot = path->slots[0];
1687         doff = btrfs_item_offset(leaf->items + slot);
1688         dsize = btrfs_item_size(leaf->items + slot);
1689         nritems = btrfs_header_nritems(&leaf->header);
1690
1691         if (slot != nritems - 1) {
1692                 int i;
1693                 int data_end = leaf_data_end(root, leaf);
1694                 btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
1695                               data_end + dsize,
1696                               btrfs_leaf_data(leaf) + data_end,
1697                               doff - data_end);
1698                 for (i = slot + 1; i < nritems; i++) {
1699                         u32 ioff = btrfs_item_offset(leaf->items + i);
1700                         btrfs_set_item_offset(leaf->items + i, ioff + dsize);
1701                 }
1702                 btrfs_memmove(root, leaf, leaf->items + slot,
1703                               leaf->items + slot + 1,
1704                               sizeof(struct btrfs_item) *
1705                               (nritems - slot - 1));
1706         }
1707         btrfs_set_header_nritems(&leaf->header, nritems - 1);
1708         nritems--;
1709         /* delete the leaf if we've emptied it */
1710         if (nritems == 0) {
1711                 if (leaf_buf == root->node) {
1712                         btrfs_set_header_level(&leaf->header, 0);
1713                 } else {
1714                         clean_tree_block(trans, root, leaf_buf);
1715                         wait_on_buffer(leaf_buf);
1716                         wret = del_ptr(trans, root, path, 1, path->slots[1]);
1717                         if (wret)
1718                                 ret = wret;
1719                         wret = btrfs_free_extent(trans, root,
1720                                                  bh_blocknr(leaf_buf), 1, 1);
1721                         if (wret)
1722                                 ret = wret;
1723                 }
1724         } else {
1725                 int used = leaf_space_used(leaf, 0, nritems);
1726                 if (slot == 0) {
1727                         wret = fixup_low_keys(trans, root, path,
1728                                               &leaf->items[0].key, 1);
1729                         if (wret)
1730                                 ret = wret;
1731                 }
1732
1733                 /* delete the leaf if it is mostly empty */
1734                 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
1735                         /* push_leaf_left fixes the path.
1736                          * make sure the path still points to our leaf
1737                          * for possible call to del_ptr below
1738                          */
1739                         slot = path->slots[1];
1740                         get_bh(leaf_buf);
1741                         wret = push_leaf_left(trans, root, path, 1);
1742                         if (wret < 0)
1743                                 ret = wret;
1744                         if (path->nodes[0] == leaf_buf &&
1745                             btrfs_header_nritems(&leaf->header)) {
1746                                 wret = push_leaf_right(trans, root, path, 1);
1747                                 if (wret < 0)
1748                                         ret = wret;
1749                         }
1750                         if (btrfs_header_nritems(&leaf->header) == 0) {
1751                                 u64 blocknr = bh_blocknr(leaf_buf);
1752                                 clean_tree_block(trans, root, leaf_buf);
1753                                 wait_on_buffer(leaf_buf);
1754                                 wret = del_ptr(trans, root, path, 1, slot);
1755                                 if (wret)
1756                                         ret = wret;
1757                                 btrfs_block_release(root, leaf_buf);
1758                                 wret = btrfs_free_extent(trans, root, blocknr,
1759                                                          1, 1);
1760                                 if (wret)
1761                                         ret = wret;
1762                         } else {
1763                                 btrfs_mark_buffer_dirty(leaf_buf);
1764                                 btrfs_block_release(root, leaf_buf);
1765                         }
1766                 } else {
1767                         btrfs_mark_buffer_dirty(leaf_buf);
1768                 }
1769         }
1770         return ret;
1771 }
1772
1773 /*
1774  * walk up the tree as far as required to find the next leaf.
1775  * returns 0 if it found something or 1 if there are no greater leaves.
1776  * returns < 0 on io errors.
1777  */
1778 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
1779 {
1780         int slot;
1781         int level = 1;
1782         u64 blocknr;
1783         struct buffer_head *c;
1784         struct btrfs_node *c_node;
1785         struct buffer_head *next = NULL;
1786
1787         while(level < BTRFS_MAX_LEVEL) {
1788                 if (!path->nodes[level])
1789                         return 1;
1790                 slot = path->slots[level] + 1;
1791                 c = path->nodes[level];
1792                 c_node = btrfs_buffer_node(c);
1793                 if (slot >= btrfs_header_nritems(&c_node->header)) {
1794                         level++;
1795                         continue;
1796                 }
1797                 blocknr = btrfs_node_blockptr(c_node, slot);
1798                 if (next)
1799                         btrfs_block_release(root, next);
1800                 next = read_tree_block(root, blocknr);
1801                 break;
1802         }
1803         path->slots[level] = slot;
1804         while(1) {
1805                 level--;
1806                 c = path->nodes[level];
1807                 btrfs_block_release(root, c);
1808                 path->nodes[level] = next;
1809                 path->slots[level] = 0;
1810                 if (!level)
1811                         break;
1812                 next = read_tree_block(root,
1813                        btrfs_node_blockptr(btrfs_buffer_node(next), 0));
1814         }
1815         return 0;
1816 }