git.oblomov.eu Git - linux-2.6/blob - fs/btrfs/super.c

   1 #include <linux/module.h>
   2 #include <linux/buffer_head.h>
   3 #include <linux/fs.h>
   4 #include <linux/pagemap.h>
   5 #include <linux/highmem.h>
   6 #include <linux/time.h>
   7 #include <linux/init.h>
   8 #include <linux/string.h>
   9 #include <linux/smp_lock.h>
  10 #include <linux/backing-dev.h>
  11 #include <linux/mpage.h>
  12 #include <linux/swap.h>
  13 #include <linux/writeback.h>
  14 #include <linux/statfs.h>
  15 #include "ctree.h"
  16 #include "disk-io.h"
  17 #include "transaction.h"
  18 #include "btrfs_inode.h"
  19 #include "ioctl.h"
  20
  21 struct btrfs_iget_args {
  22         u64 ino;
  23         struct btrfs_root *root;
  24 };
  25
  26 #define BTRFS_SUPER_MAGIC 0x9123682E
  27
  28 static struct inode_operations btrfs_dir_inode_operations;
  29 static struct inode_operations btrfs_dir_ro_inode_operations;
  30 static struct super_operations btrfs_super_ops;
  31 static struct file_operations btrfs_dir_file_operations;
  32 static struct inode_operations btrfs_file_inode_operations;
  33 static struct address_space_operations btrfs_aops;
  34 static struct file_operations btrfs_file_operations;
  35
  36 static void btrfs_read_locked_inode(struct inode *inode)
  37 {
  38         struct btrfs_path *path;
  39         struct btrfs_inode_item *inode_item;
  40         struct btrfs_root *root = BTRFS_I(inode)->root;
  41         struct btrfs_key location;
  42         struct btrfs_block_group_cache *alloc_group;
  43         u64 alloc_group_block;
  44         int ret;
  45
  46         path = btrfs_alloc_path();
  47         BUG_ON(!path);
  48         btrfs_init_path(path);
  49         mutex_lock(&root->fs_info->fs_mutex);
  50
  51         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
  52         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
  53         if (ret) {
  54                 btrfs_free_path(path);
  55                 goto make_bad;
  56         }
  57         inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
  58                                   path->slots[0],
  59                                   struct btrfs_inode_item);
  60
  61         inode->i_mode = btrfs_inode_mode(inode_item);
  62         inode->i_nlink = btrfs_inode_nlink(inode_item);
  63         inode->i_uid = btrfs_inode_uid(inode_item);
  64         inode->i_gid = btrfs_inode_gid(inode_item);
  65         inode->i_size = btrfs_inode_size(inode_item);
  66         inode->i_atime.tv_sec = btrfs_timespec_sec(&inode_item->atime);
  67         inode->i_atime.tv_nsec = btrfs_timespec_nsec(&inode_item->atime);
  68         inode->i_mtime.tv_sec = btrfs_timespec_sec(&inode_item->mtime);
  69         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(&inode_item->mtime);
  70         inode->i_ctime.tv_sec = btrfs_timespec_sec(&inode_item->ctime);
  71         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(&inode_item->ctime);
  72         inode->i_blocks = btrfs_inode_nblocks(inode_item);
  73         inode->i_generation = btrfs_inode_generation(inode_item);
  74         alloc_group_block = btrfs_inode_block_group(inode_item);
  75         ret = radix_tree_gang_lookup(&root->fs_info->block_group_radix,
  76                                      (void **)&alloc_group,
  77                                      alloc_group_block, 1);
  78         BUG_ON(!ret);
  79         BTRFS_I(inode)->block_group = alloc_group;
  80
  81         btrfs_free_path(path);
  82         inode_item = NULL;
  83
  84         mutex_unlock(&root->fs_info->fs_mutex);
  85
  86         switch (inode->i_mode & S_IFMT) {
  87 #if 0
  88         default:
  89                 init_special_inode(inode, inode->i_mode,
  90                                    btrfs_inode_rdev(inode_item));
  91                 break;
  92 #endif
  93         case S_IFREG:
  94                 inode->i_mapping->a_ops = &btrfs_aops;
  95                 inode->i_fop = &btrfs_file_operations;
  96                 inode->i_op = &btrfs_file_inode_operations;
  97                 break;
  98         case S_IFDIR:
  99                 inode->i_fop = &btrfs_dir_file_operations;
 100                 if (root == root->fs_info->tree_root)
 101                         inode->i_op = &btrfs_dir_ro_inode_operations;
 102                 else
 103                         inode->i_op = &btrfs_dir_inode_operations;
 104                 break;
 105         case S_IFLNK:
 106                 // inode->i_op = &page_symlink_inode_operations;
 107                 break;
 108         }
 109         return;
 110
 111 make_bad:
 112         btrfs_release_path(root, path);
 113         btrfs_free_path(path);
 114         mutex_unlock(&root->fs_info->fs_mutex);
 115         make_bad_inode(inode);
 116 }
 117
 118 static void fill_inode_item(struct btrfs_inode_item *item,
 119                             struct inode *inode)
 120 {
 121         btrfs_set_inode_uid(item, inode->i_uid);
 122         btrfs_set_inode_gid(item, inode->i_gid);
 123         btrfs_set_inode_size(item, inode->i_size);
 124         btrfs_set_inode_mode(item, inode->i_mode);
 125         btrfs_set_inode_nlink(item, inode->i_nlink);
 126         btrfs_set_timespec_sec(&item->atime, inode->i_atime.tv_sec);
 127         btrfs_set_timespec_nsec(&item->atime, inode->i_atime.tv_nsec);
 128         btrfs_set_timespec_sec(&item->mtime, inode->i_mtime.tv_sec);
 129         btrfs_set_timespec_nsec(&item->mtime, inode->i_mtime.tv_nsec);
 130         btrfs_set_timespec_sec(&item->ctime, inode->i_ctime.tv_sec);
 131         btrfs_set_timespec_nsec(&item->ctime, inode->i_ctime.tv_nsec);
 132         btrfs_set_inode_nblocks(item, inode->i_blocks);
 133         btrfs_set_inode_generation(item, inode->i_generation);
 134         btrfs_set_inode_block_group(item,
 135                                     BTRFS_I(inode)->block_group->key.objectid);
 136 }
 137
 138 static int btrfs_update_inode(struct btrfs_trans_handle *trans,
 139                               struct btrfs_root *root,
 140                               struct inode *inode)
 141 {
 142         struct btrfs_inode_item *inode_item;
 143         struct btrfs_path *path;
 144         int ret;
 145
 146         path = btrfs_alloc_path();
 147         BUG_ON(!path);
 148         btrfs_init_path(path);
 149         ret = btrfs_lookup_inode(trans, root, path,
 150                                  &BTRFS_I(inode)->location, 1);
 151         if (ret) {
 152                 if (ret > 0)
 153                         ret = -ENOENT;
 154                 goto failed;
 155         }
 156
 157         inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
 158                                   path->slots[0],
 159                                   struct btrfs_inode_item);
 160
 161         fill_inode_item(inode_item, inode);
 162         btrfs_mark_buffer_dirty(path->nodes[0]);
 163         ret = 0;
 164 failed:
 165         btrfs_release_path(root, path);
 166         btrfs_free_path(path);
 167         return ret;
 168 }
 169
 170
 171 static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
 172                               struct btrfs_root *root,
 173                               struct inode *dir,
 174                               struct dentry *dentry)
 175 {
 176         struct btrfs_path *path;
 177         const char *name = dentry->d_name.name;
 178         int name_len = dentry->d_name.len;
 179         int ret = 0;
 180         u64 objectid;
 181         struct btrfs_dir_item *di;
 182
 183         path = btrfs_alloc_path();
 184         BUG_ON(!path);
 185         btrfs_init_path(path);
 186         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
 187                                     name, name_len, -1);
 188         if (IS_ERR(di)) {
 189                 ret = PTR_ERR(di);
 190                 goto err;
 191         }
 192         if (!di) {
 193                 ret = -ENOENT;
 194                 goto err;
 195         }
 196         objectid = btrfs_disk_key_objectid(&di->location);
 197         ret = btrfs_delete_one_dir_name(trans, root, path, di);
 198         BUG_ON(ret);
 199         btrfs_release_path(root, path);
 200
 201         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
 202                                          objectid, name, name_len, -1);
 203         if (IS_ERR(di)) {
 204                 ret = PTR_ERR(di);
 205                 goto err;
 206         }
 207         if (!di) {
 208                 ret = -ENOENT;
 209                 goto err;
 210         }
 211         ret = btrfs_delete_one_dir_name(trans, root, path, di);
 212         BUG_ON(ret);
 213
 214         dentry->d_inode->i_ctime = dir->i_ctime;
 215 err:
 216         btrfs_free_path(path);
 217         if (!ret) {
 218                 dir->i_size -= name_len * 2;
 219                 btrfs_update_inode(trans, root, dir);
 220                 drop_nlink(dentry->d_inode);
 221                 btrfs_update_inode(trans, root, dentry->d_inode);
 222                 dir->i_sb->s_dirt = 1;
 223         }
 224         return ret;
 225 }
 226
 227 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
 228 {
 229         struct btrfs_root *root;
 230         struct btrfs_trans_handle *trans;
 231         int ret;
 232
 233         root = BTRFS_I(dir)->root;
 234         mutex_lock(&root->fs_info->fs_mutex);
 235         trans = btrfs_start_transaction(root, 1);
 236         btrfs_set_trans_block_group(trans, dir);
 237         ret = btrfs_unlink_trans(trans, root, dir, dentry);
 238         btrfs_end_transaction(trans, root);
 239         mutex_unlock(&root->fs_info->fs_mutex);
 240         btrfs_btree_balance_dirty(root);
 241         return ret;
 242 }
 243
 244 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 245 {
 246         struct inode *inode = dentry->d_inode;
 247         int err;
 248         int ret;
 249         struct btrfs_root *root = BTRFS_I(dir)->root;
 250         struct btrfs_path *path;
 251         struct btrfs_key key;
 252         struct btrfs_trans_handle *trans;
 253         struct btrfs_key found_key;
 254         int found_type;
 255         struct btrfs_leaf *leaf;
 256         char *goodnames = "..";
 257
 258         path = btrfs_alloc_path();
 259         BUG_ON(!path);
 260         btrfs_init_path(path);
 261         mutex_lock(&root->fs_info->fs_mutex);
 262         trans = btrfs_start_transaction(root, 1);
 263         btrfs_set_trans_block_group(trans, dir);
 264         key.objectid = inode->i_ino;
 265         key.offset = (u64)-1;
 266         key.flags = (u32)-1;
 267         while(1) {
 268                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 269                 if (ret < 0) {
 270                         err = ret;
 271                         goto out;
 272                 }
 273                 BUG_ON(ret == 0);
 274                 if (path->slots[0] == 0) {
 275                         err = -ENOENT;
 276                         goto out;
 277                 }
 278                 path->slots[0]--;
 279                 leaf = btrfs_buffer_leaf(path->nodes[0]);
 280                 btrfs_disk_key_to_cpu(&found_key,
 281                                       &leaf->items[path->slots[0]].key);
 282                 found_type = btrfs_key_type(&found_key);
 283                 if (found_key.objectid != inode->i_ino) {
 284                         err = -ENOENT;
 285                         goto out;
 286                 }
 287                 if ((found_type != BTRFS_DIR_ITEM_KEY &&
 288                      found_type != BTRFS_DIR_INDEX_KEY) ||
 289                     (!btrfs_match_dir_item_name(root, path, goodnames, 2) &&
 290                     !btrfs_match_dir_item_name(root, path, goodnames, 1))) {
 291                         err = -ENOTEMPTY;
 292                         goto out;
 293                 }
 294                 ret = btrfs_del_item(trans, root, path);
 295                 BUG_ON(ret);
 296
 297                 if (found_type == BTRFS_DIR_ITEM_KEY && found_key.offset == 1)
 298                         break;
 299                 btrfs_release_path(root, path);
 300         }
 301         ret = 0;
 302         btrfs_release_path(root, path);
 303
 304         /* now the directory is empty */
 305         err = btrfs_unlink_trans(trans, root, dir, dentry);
 306         if (!err) {
 307                 inode->i_size = 0;
 308         }
 309 out:
 310         btrfs_release_path(root, path);
 311         btrfs_free_path(path);
 312         mutex_unlock(&root->fs_info->fs_mutex);
 313         ret = btrfs_end_transaction(trans, root);
 314         btrfs_btree_balance_dirty(root);
 315         if (ret && !err)
 316                 err = ret;
 317         return err;
 318 }
 319
 320 static int btrfs_free_inode(struct btrfs_trans_handle *trans,
 321                             struct btrfs_root *root,
 322                             struct inode *inode)
 323 {
 324         struct btrfs_path *path;
 325         int ret;
 326
 327         clear_inode(inode);
 328
 329         path = btrfs_alloc_path();
 330         BUG_ON(!path);
 331         btrfs_init_path(path);
 332         ret = btrfs_lookup_inode(trans, root, path,
 333                                  &BTRFS_I(inode)->location, -1);
 334         BUG_ON(ret);
 335         ret = btrfs_del_item(trans, root, path);
 336         BUG_ON(ret);
 337         btrfs_free_path(path);
 338         return ret;
 339 }
 340
 341 static void reada_truncate(struct btrfs_root *root, struct btrfs_path *path,
 342                            u64 objectid)
 343 {
 344         struct btrfs_node *node;
 345         int i;
 346         int nritems;
 347         u64 item_objectid;
 348         u64 blocknr;
 349         int slot;
 350         int ret;
 351
 352         if (!path->nodes[1])
 353                 return;
 354         node = btrfs_buffer_node(path->nodes[1]);
 355         slot = path->slots[1];
 356         if (slot == 0)
 357                 return;
 358         nritems = btrfs_header_nritems(&node->header);
 359         for (i = slot - 1; i >= 0; i--) {
 360                 item_objectid = btrfs_disk_key_objectid(&node->ptrs[i].key);
 361                 if (item_objectid != objectid)
 362                         break;
 363                 blocknr = btrfs_node_blockptr(node, i);
 364                 ret = readahead_tree_block(root, blocknr);
 365                 if (ret)
 366                         break;
 367         }
 368 }
 369
 370 static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
 371                                    struct btrfs_root *root,
 372                                    struct inode *inode)
 373 {
 374         int ret;
 375         struct btrfs_path *path;
 376         struct btrfs_key key;
 377         struct btrfs_disk_key *found_key;
 378         struct btrfs_leaf *leaf;
 379         struct btrfs_file_extent_item *fi = NULL;
 380         u64 extent_start = 0;
 381         u64 extent_num_blocks = 0;
 382         int found_extent;
 383
 384         path = btrfs_alloc_path();
 385         BUG_ON(!path);
 386         /* FIXME, add redo link to tree so we don't leak on crash */
 387         key.objectid = inode->i_ino;
 388         key.offset = (u64)-1;
 389         key.flags = 0;
 390         /*
 391          * use BTRFS_CSUM_ITEM_KEY because it is larger than inline keys
 392          * or extent data
 393          */
 394         btrfs_set_key_type(&key, BTRFS_CSUM_ITEM_KEY);
 395         while(1) {
 396                 btrfs_init_path(path);
 397                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 398                 if (ret < 0) {
 399                         goto error;
 400                 }
 401                 if (ret > 0) {
 402                         BUG_ON(path->slots[0] == 0);
 403                         path->slots[0]--;
 404                 }
 405                 reada_truncate(root, path, inode->i_ino);
 406                 leaf = btrfs_buffer_leaf(path->nodes[0]);
 407                 found_key = &leaf->items[path->slots[0]].key;
 408                 if (btrfs_disk_key_objectid(found_key) != inode->i_ino)
 409                         break;
 410                 if (btrfs_disk_key_type(found_key) != BTRFS_CSUM_ITEM_KEY &&
 411                     btrfs_disk_key_type(found_key) != BTRFS_EXTENT_DATA_KEY)
 412                         break;
 413                 if (btrfs_disk_key_offset(found_key) < inode->i_size)
 414                         break;
 415                 found_extent = 0;
 416                 if (btrfs_disk_key_type(found_key) == BTRFS_EXTENT_DATA_KEY) {
 417                         fi = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
 418                                             path->slots[0],
 419                                             struct btrfs_file_extent_item);
 420                         if (btrfs_file_extent_type(fi) !=
 421                             BTRFS_FILE_EXTENT_INLINE) {
 422                                 extent_start =
 423                                         btrfs_file_extent_disk_blocknr(fi);
 424                                 extent_num_blocks =
 425                                         btrfs_file_extent_disk_num_blocks(fi);
 426                                 /* FIXME blocksize != 4096 */
 427                                 inode->i_blocks -=
 428                                         btrfs_file_extent_num_blocks(fi) << 3;
 429                                 found_extent = 1;
 430                         }
 431                 }
 432                 ret = btrfs_del_item(trans, root, path);
 433                 BUG_ON(ret);
 434                 btrfs_release_path(root, path);
 435                 if (found_extent) {
 436                         ret = btrfs_free_extent(trans, root, extent_start,
 437                                                 extent_num_blocks, 0);
 438                         BUG_ON(ret);
 439                 }
 440         }
 441         ret = 0;
 442 error:
 443         btrfs_release_path(root, path);
 444         btrfs_free_path(path);
 445         inode->i_sb->s_dirt = 1;
 446         return ret;
 447 }
 448
 449 static void btrfs_delete_inode(struct inode *inode)
 450 {
 451         struct btrfs_trans_handle *trans;
 452         struct btrfs_root *root = BTRFS_I(inode)->root;
 453         int ret;
 454
 455         truncate_inode_pages(&inode->i_data, 0);
 456         if (is_bad_inode(inode)) {
 457                 goto no_delete;
 458         }
 459         inode->i_size = 0;
 460         mutex_lock(&root->fs_info->fs_mutex);
 461         trans = btrfs_start_transaction(root, 1);
 462         btrfs_set_trans_block_group(trans, inode);
 463         if (S_ISREG(inode->i_mode)) {
 464                 ret = btrfs_truncate_in_trans(trans, root, inode);
 465                 BUG_ON(ret);
 466         }
 467         btrfs_free_inode(trans, root, inode);
 468         btrfs_end_transaction(trans, root);
 469         mutex_unlock(&root->fs_info->fs_mutex);
 470         btrfs_btree_balance_dirty(root);
 471         return;
 472 no_delete:
 473         clear_inode(inode);
 474 }
 475
 476 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
 477                                struct btrfs_key *location)
 478 {
 479         const char *name = dentry->d_name.name;
 480         int namelen = dentry->d_name.len;
 481         struct btrfs_dir_item *di;
 482         struct btrfs_path *path;
 483         struct btrfs_root *root = BTRFS_I(dir)->root;
 484         int ret;
 485
 486         path = btrfs_alloc_path();
 487         BUG_ON(!path);
 488         btrfs_init_path(path);
 489         di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
 490                                     namelen, 0);
 491         if (!di || IS_ERR(di)) {
 492                 location->objectid = 0;
 493                 ret = 0;
 494                 goto out;
 495         }
 496         btrfs_disk_key_to_cpu(location, &di->location);
 497 out:
 498         btrfs_release_path(root, path);
 499         btrfs_free_path(path);
 500         return ret;
 501 }
 502
 503 static int fixup_tree_root_location(struct btrfs_root *root,
 504                              struct btrfs_key *location,
 505                              struct btrfs_root **sub_root)
 506 {
 507         struct btrfs_path *path;
 508         struct btrfs_root_item *ri;
 509
 510         if (btrfs_key_type(location) != BTRFS_ROOT_ITEM_KEY)
 511                 return 0;
 512         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
 513                 return 0;
 514
 515         path = btrfs_alloc_path();
 516         BUG_ON(!path);
 517         mutex_lock(&root->fs_info->fs_mutex);
 518
 519         *sub_root = btrfs_read_fs_root(root->fs_info, location);
 520         if (IS_ERR(*sub_root))
 521                 return PTR_ERR(*sub_root);
 522
 523         ri = &(*sub_root)->root_item;
 524         location->objectid = btrfs_root_dirid(ri);
 525         location->flags = 0;
 526         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
 527         location->offset = 0;
 528
 529         btrfs_free_path(path);
 530         mutex_unlock(&root->fs_info->fs_mutex);
 531         return 0;
 532 }
 533
 534 static int btrfs_init_locked_inode(struct inode *inode, void *p)
 535 {
 536         struct btrfs_iget_args *args = p;
 537         inode->i_ino = args->ino;
 538         BTRFS_I(inode)->root = args->root;
 539         return 0;
 540 }
 541
 542 static int btrfs_find_actor(struct inode *inode, void *opaque)
 543 {
 544         struct btrfs_iget_args *args = opaque;
 545         return (args->ino == inode->i_ino &&
 546                 args->root == BTRFS_I(inode)->root);
 547 }
 548
 549 static struct inode *btrfs_iget_locked(struct super_block *s, u64 objectid,
 550                                        struct btrfs_root *root)
 551 {
 552         struct inode *inode;
 553         struct btrfs_iget_args args;
 554         args.ino = objectid;
 555         args.root = root;
 556
 557         inode = iget5_locked(s, objectid, btrfs_find_actor,
 558                              btrfs_init_locked_inode,
 559                              (void *)&args);
 560         return inode;
 561 }
 562
 563 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
 564                                    struct nameidata *nd)
 565 {
 566         struct inode * inode;
 567         struct btrfs_inode *bi = BTRFS_I(dir);
 568         struct btrfs_root *root = bi->root;
 569         struct btrfs_root *sub_root = root;
 570         struct btrfs_key location;
 571         int ret;
 572
 573         if (dentry->d_name.len > BTRFS_NAME_LEN)
 574                 return ERR_PTR(-ENAMETOOLONG);
 575         mutex_lock(&root->fs_info->fs_mutex);
 576         ret = btrfs_inode_by_name(dir, dentry, &location);
 577         mutex_unlock(&root->fs_info->fs_mutex);
 578         if (ret < 0)
 579                 return ERR_PTR(ret);
 580         inode = NULL;
 581         if (location.objectid) {
 582                 ret = fixup_tree_root_location(root, &location, &sub_root);
 583                 if (ret < 0)
 584                         return ERR_PTR(ret);
 585                 if (ret > 0)
 586                         return ERR_PTR(-ENOENT);
 587                 inode = btrfs_iget_locked(dir->i_sb, location.objectid,
 588                                           sub_root);
 589                 if (!inode)
 590                         return ERR_PTR(-EACCES);
 591                 if (inode->i_state & I_NEW) {
 592                         if (sub_root != root) {
 593 printk("adding new root for inode %lu root %p (found %p)\n", inode->i_ino, sub_root, BTRFS_I(inode)->root);
 594                                 igrab(inode);
 595                                 sub_root->inode = inode;
 596                         }
 597                         BTRFS_I(inode)->root = sub_root;
 598                         memcpy(&BTRFS_I(inode)->location, &location,
 599                                sizeof(location));
 600                         btrfs_read_locked_inode(inode);
 601                         unlock_new_inode(inode);
 602                 }
 603         }
 604         return d_splice_alias(inode, dentry);
 605 }
 606
 607 static void reada_leaves(struct btrfs_root *root, struct btrfs_path *path,
 608                          u64 objectid)
 609 {
 610         struct btrfs_node *node;
 611         int i;
 612         u32 nritems;
 613         u64 item_objectid;
 614         u64 blocknr;
 615         int slot;
 616         int ret;
 617
 618         if (!path->nodes[1])
 619                 return;
 620         node = btrfs_buffer_node(path->nodes[1]);
 621         slot = path->slots[1];
 622         nritems = btrfs_header_nritems(&node->header);
 623         for (i = slot + 1; i < nritems; i++) {
 624                 item_objectid = btrfs_disk_key_objectid(&node->ptrs[i].key);
 625                 if (item_objectid != objectid)
 626                         break;
 627                 blocknr = btrfs_node_blockptr(node, i);
 628                 ret = readahead_tree_block(root, blocknr);
 629                 if (ret)
 630                         break;
 631         }
 632 }
 633
 634 static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 635 {
 636         struct inode *inode = filp->f_path.dentry->d_inode;
 637         struct btrfs_root *root = BTRFS_I(inode)->root;
 638         struct btrfs_item *item;
 639         struct btrfs_dir_item *di;
 640         struct btrfs_key key;
 641         struct btrfs_path *path;
 642         int ret;
 643         u32 nritems;
 644         struct btrfs_leaf *leaf;
 645         int slot;
 646         int advance;
 647         unsigned char d_type = DT_UNKNOWN;
 648         int over = 0;
 649         u32 di_cur;
 650         u32 di_total;
 651         u32 di_len;
 652         int key_type = BTRFS_DIR_INDEX_KEY;
 653
 654         /* FIXME, use a real flag for deciding about the key type */
 655         if (root->fs_info->tree_root == root)
 656                 key_type = BTRFS_DIR_ITEM_KEY;
 657         mutex_lock(&root->fs_info->fs_mutex);
 658         key.objectid = inode->i_ino;
 659         key.flags = 0;
 660         btrfs_set_key_type(&key, key_type);
 661         key.offset = filp->f_pos;
 662         path = btrfs_alloc_path();
 663         btrfs_init_path(path);
 664         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 665         if (ret < 0)
 666                 goto err;
 667         advance = 0;
 668         reada_leaves(root, path, inode->i_ino);
 669         while(1) {
 670                 leaf = btrfs_buffer_leaf(path->nodes[0]);
 671                 nritems = btrfs_header_nritems(&leaf->header);
 672                 slot = path->slots[0];
 673                 if (advance || slot >= nritems) {
 674                         if (slot >= nritems -1) {
 675                                 reada_leaves(root, path, inode->i_ino);
 676                                 ret = btrfs_next_leaf(root, path);
 677                                 if (ret)
 678                                         break;
 679                                 leaf = btrfs_buffer_leaf(path->nodes[0]);
 680                                 nritems = btrfs_header_nritems(&leaf->header);
 681                                 slot = path->slots[0];
 682                         } else {
 683                                 slot++;
 684                                 path->slots[0]++;
 685                         }
 686                 }
 687                 advance = 1;
 688                 item = leaf->items + slot;
 689                 if (btrfs_disk_key_objectid(&item->key) != key.objectid)
 690                         break;
 691                 if (btrfs_disk_key_type(&item->key) != key_type)
 692                         break;
 693                 if (btrfs_disk_key_offset(&item->key) < filp->f_pos)
 694                         continue;
 695                 filp->f_pos = btrfs_disk_key_offset(&item->key);
 696                 advance = 1;
 697                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
 698                 di_cur = 0;
 699                 di_total = btrfs_item_size(leaf->items + slot);
 700                 while(di_cur < di_total) {
 701                         over = filldir(dirent, (const char *)(di + 1),
 702                                        btrfs_dir_name_len(di),
 703                                        btrfs_disk_key_offset(&item->key),
 704                                        btrfs_disk_key_objectid(&di->location),
 705                                        d_type);
 706                         if (over)
 707                                 goto nopos;
 708                         di_len = btrfs_dir_name_len(di) + sizeof(*di);
 709                         di_cur += di_len;
 710                         di = (struct btrfs_dir_item *)((char *)di + di_len);
 711                 }
 712         }
 713         filp->f_pos++;
 714 nopos:
 715         ret = 0;
 716 err:
 717         btrfs_release_path(root, path);
 718         btrfs_free_path(path);
 719         mutex_unlock(&root->fs_info->fs_mutex);
 720         return ret;
 721 }
 722
 723 static void btrfs_put_super (struct super_block * sb)
 724 {
 725         struct btrfs_root *root = btrfs_sb(sb);
 726         int ret;
 727
 728         ret = close_ctree(root);
 729         if (ret) {
 730                 printk("close ctree returns %d\n", ret);
 731         }
 732         sb->s_fs_info = NULL;
 733 }
 734
 735 static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
 736 {
 737         struct inode * inode;
 738         struct dentry * root_dentry;
 739         struct btrfs_super_block *disk_super;
 740         struct btrfs_root *tree_root;
 741         struct btrfs_inode *bi;
 742
 743         sb->s_maxbytes = MAX_LFS_FILESIZE;
 744         sb->s_magic = BTRFS_SUPER_MAGIC;
 745         sb->s_op = &btrfs_super_ops;
 746         sb->s_time_gran = 1;
 747
 748         tree_root = open_ctree(sb);
 749
 750         if (!tree_root) {
 751                 printk("btrfs: open_ctree failed\n");
 752                 return -EIO;
 753         }
 754         sb->s_fs_info = tree_root;
 755         disk_super = tree_root->fs_info->disk_super;
 756         printk("read in super total blocks %Lu root %Lu\n",
 757                btrfs_super_total_blocks(disk_super),
 758                btrfs_super_root_dir(disk_super));
 759
 760         inode = btrfs_iget_locked(sb, btrfs_super_root_dir(disk_super),
 761                                   tree_root);
 762         bi = BTRFS_I(inode);
 763         bi->location.objectid = inode->i_ino;
 764         bi->location.offset = 0;
 765         bi->location.flags = 0;
 766         bi->root = tree_root;
 767         btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
 768
 769         if (!inode)
 770                 return -ENOMEM;
 771         if (inode->i_state & I_NEW) {
 772                 btrfs_read_locked_inode(inode);
 773                 unlock_new_inode(inode);
 774         }
 775
 776         root_dentry = d_alloc_root(inode);
 777         if (!root_dentry) {
 778                 iput(inode);
 779                 return -ENOMEM;
 780         }
 781         sb->s_root = root_dentry;
 782
 783         return 0;
 784 }
 785
 786 static int btrfs_write_inode(struct inode *inode, int wait)
 787 {
 788         struct btrfs_root *root = BTRFS_I(inode)->root;
 789         struct btrfs_trans_handle *trans;
 790         int ret = 0;
 791
 792         if (wait) {
 793                 mutex_lock(&root->fs_info->fs_mutex);
 794                 trans = btrfs_start_transaction(root, 1);
 795                 btrfs_set_trans_block_group(trans, inode);
 796                 ret = btrfs_commit_transaction(trans, root);
 797                 mutex_unlock(&root->fs_info->fs_mutex);
 798         }
 799         return ret;
 800 }
 801
 802 static void btrfs_dirty_inode(struct inode *inode)
 803 {
 804         struct btrfs_root *root = BTRFS_I(inode)->root;
 805         struct btrfs_trans_handle *trans;
 806
 807         mutex_lock(&root->fs_info->fs_mutex);
 808         trans = btrfs_start_transaction(root, 1);
 809         btrfs_set_trans_block_group(trans, inode);
 810         btrfs_update_inode(trans, root, inode);
 811         btrfs_end_transaction(trans, root);
 812         mutex_unlock(&root->fs_info->fs_mutex);
 813         btrfs_btree_balance_dirty(root);
 814 }
 815
 816 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
 817                                      struct btrfs_root *root,
 818                                      u64 objectid,
 819                                      struct btrfs_block_group_cache *group,
 820                                      int mode)
 821 {
 822         struct inode *inode;
 823         struct btrfs_inode_item inode_item;
 824         struct btrfs_key *location;
 825         int ret;
 826         int owner;
 827
 828         inode = new_inode(root->fs_info->sb);
 829         if (!inode)
 830                 return ERR_PTR(-ENOMEM);
 831
 832         BTRFS_I(inode)->root = root;
 833         if (mode & S_IFDIR)
 834                 owner = 0;
 835         else
 836                 owner = 1;
 837         group = btrfs_find_block_group(root, group, 0, 0, owner);
 838         BTRFS_I(inode)->block_group = group;
 839
 840         inode->i_uid = current->fsuid;
 841         inode->i_gid = current->fsgid;
 842         inode->i_mode = mode;
 843         inode->i_ino = objectid;
 844         inode->i_blocks = 0;
 845         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 846         fill_inode_item(&inode_item, inode);
 847         location = &BTRFS_I(inode)->location;
 848         location->objectid = objectid;
 849         location->flags = 0;
 850         location->offset = 0;
 851         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
 852
 853         ret = btrfs_insert_inode(trans, root, objectid, &inode_item);
 854         BUG_ON(ret);
 855
 856         insert_inode_hash(inode);
 857         return inode;
 858 }
 859
 860 static int btrfs_add_link(struct btrfs_trans_handle *trans,
 861                             struct dentry *dentry, struct inode *inode)
 862 {
 863         int ret;
 864         struct btrfs_key key;
 865         struct btrfs_root *root = BTRFS_I(dentry->d_parent->d_inode)->root;
 866         key.objectid = inode->i_ino;
 867         key.flags = 0;
 868         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
 869         key.offset = 0;
 870
 871         ret = btrfs_insert_dir_item(trans, root,
 872                                     dentry->d_name.name, dentry->d_name.len,
 873                                     dentry->d_parent->d_inode->i_ino,
 874                                     &key, 0);
 875         if (ret == 0) {
 876                 dentry->d_parent->d_inode->i_size += dentry->d_name.len * 2;
 877                 ret = btrfs_update_inode(trans, root,
 878                                          dentry->d_parent->d_inode);
 879         }
 880         return ret;
 881 }
 882
 883 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
 884                             struct dentry *dentry, struct inode *inode)
 885 {
 886         int err = btrfs_add_link(trans, dentry, inode);
 887         if (!err) {
 888                 d_instantiate(dentry, inode);
 889                 return 0;
 890         }
 891         if (err > 0)
 892                 err = -EEXIST;
 893         return err;
 894 }
 895
 896 static int btrfs_create(struct inode *dir, struct dentry *dentry,
 897                         int mode, struct nameidata *nd)
 898 {
 899         struct btrfs_trans_handle *trans;
 900         struct btrfs_root *root = BTRFS_I(dir)->root;
 901         struct inode *inode;
 902         int err;
 903         int drop_inode = 0;
 904         u64 objectid;
 905
 906         mutex_lock(&root->fs_info->fs_mutex);
 907         trans = btrfs_start_transaction(root, 1);
 908         btrfs_set_trans_block_group(trans, dir);
 909
 910         err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
 911         if (err) {
 912                 err = -ENOSPC;
 913                 goto out_unlock;
 914         }
 915
 916         inode = btrfs_new_inode(trans, root, objectid,
 917                                 BTRFS_I(dir)->block_group, mode);
 918         err = PTR_ERR(inode);
 919         if (IS_ERR(inode))
 920                 goto out_unlock;
 921
 922         btrfs_set_trans_block_group(trans, inode);
 923         err = btrfs_add_nondir(trans, dentry, inode);
 924         if (err)
 925                 drop_inode = 1;
 926         else {
 927                 inode->i_mapping->a_ops = &btrfs_aops;
 928                 inode->i_fop = &btrfs_file_operations;
 929                 inode->i_op = &btrfs_file_inode_operations;
 930         }
 931         dir->i_sb->s_dirt = 1;
 932         btrfs_update_inode_block_group(trans, inode);
 933         btrfs_update_inode_block_group(trans, dir);
 934 out_unlock:
 935         btrfs_end_transaction(trans, root);
 936         mutex_unlock(&root->fs_info->fs_mutex);
 937
 938         if (drop_inode) {
 939                 inode_dec_link_count(inode);
 940                 iput(inode);
 941         }
 942         btrfs_btree_balance_dirty(root);
 943         return err;
 944 }
 945
 946 static int btrfs_make_empty_dir(struct btrfs_trans_handle *trans,
 947                                 struct btrfs_root *root,
 948                                 u64 objectid, u64 dirid)
 949 {
 950         int ret;
 951         char buf[2];
 952         struct btrfs_key key;
 953
 954         buf[0] = '.';
 955         buf[1] = '.';
 956
 957         key.objectid = objectid;
 958         key.offset = 0;
 959         key.flags = 0;
 960         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
 961
 962         ret = btrfs_insert_dir_item(trans, root, buf, 1, objectid,
 963                                     &key, 1);
 964         if (ret)
 965                 goto error;
 966         key.objectid = dirid;
 967         ret = btrfs_insert_dir_item(trans, root, buf, 2, objectid,
 968                                     &key, 1);
 969         if (ret)
 970                 goto error;
 971 error:
 972         return ret;
 973 }
 974
 975 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 976 {
 977         struct inode *inode;
 978         struct btrfs_trans_handle *trans;
 979         struct btrfs_root *root = BTRFS_I(dir)->root;
 980         int err = 0;
 981         int drop_on_err = 0;
 982         u64 objectid;
 983
 984         mutex_lock(&root->fs_info->fs_mutex);
 985         trans = btrfs_start_transaction(root, 1);
 986         btrfs_set_trans_block_group(trans, dir);
 987         if (IS_ERR(trans)) {
 988                 err = PTR_ERR(trans);
 989                 goto out_unlock;
 990         }
 991
 992         err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
 993         if (err) {
 994                 err = -ENOSPC;
 995                 goto out_unlock;
 996         }
 997
 998         inode = btrfs_new_inode(trans, root, objectid,
 999                                 BTRFS_I(dir)->block_group, S_IFDIR | mode);
1000         if (IS_ERR(inode)) {
1001                 err = PTR_ERR(inode);
1002                 goto out_fail;
1003         }
1004         drop_on_err = 1;
1005         inode->i_op = &btrfs_dir_inode_operations;
1006         inode->i_fop = &btrfs_dir_file_operations;
1007         btrfs_set_trans_block_group(trans, inode);
1008
1009         err = btrfs_make_empty_dir(trans, root, inode->i_ino, dir->i_ino);
1010         if (err)
1011                 goto out_fail;
1012
1013         inode->i_size = 6;
1014         err = btrfs_update_inode(trans, root, inode);
1015         if (err)
1016                 goto out_fail;
1017         err = btrfs_add_link(trans, dentry, inode);
1018         if (err)
1019                 goto out_fail;
1020         d_instantiate(dentry, inode);
1021         drop_on_err = 0;
1022         dir->i_sb->s_dirt = 1;
1023         btrfs_update_inode_block_group(trans, inode);
1024         btrfs_update_inode_block_group(trans, dir);
1025
1026 out_fail:
1027         btrfs_end_transaction(trans, root);
1028 out_unlock:
1029         mutex_unlock(&root->fs_info->fs_mutex);
1030         if (drop_on_err)
1031                 iput(inode);
1032         btrfs_btree_balance_dirty(root);
1033         return err;
1034 }
1035
1036 static int btrfs_sync_file(struct file *file,
1037                            struct dentry *dentry, int datasync)
1038 {
1039         struct inode *inode = dentry->d_inode;
1040         struct btrfs_root *root = BTRFS_I(inode)->root;
1041         int ret;
1042         struct btrfs_trans_handle *trans;
1043
1044         mutex_lock(&root->fs_info->fs_mutex);
1045         trans = btrfs_start_transaction(root, 1);
1046         if (!trans) {
1047                 ret = -ENOMEM;
1048                 goto out;
1049         }
1050         ret = btrfs_commit_transaction(trans, root);
1051         mutex_unlock(&root->fs_info->fs_mutex);
1052 out:
1053         return ret > 0 ? EIO : ret;
1054 }
1055
1056 static int btrfs_sync_fs(struct super_block *sb, int wait)
1057 {
1058         struct btrfs_trans_handle *trans;
1059         struct btrfs_root *root;
1060         int ret;
1061         root = btrfs_sb(sb);
1062
1063         sb->s_dirt = 0;
1064         if (!wait) {
1065                 filemap_flush(root->fs_info->btree_inode->i_mapping);
1066                 return 0;
1067         }
1068         mutex_lock(&root->fs_info->fs_mutex);
1069         trans = btrfs_start_transaction(root, 1);
1070         ret = btrfs_commit_transaction(trans, root);
1071         sb->s_dirt = 0;
1072         BUG_ON(ret);
1073 printk("btrfs sync_fs\n");
1074         mutex_unlock(&root->fs_info->fs_mutex);
1075         return 0;
1076 }
1077
1078 static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
1079                            struct buffer_head *result, int create)
1080 {
1081         int ret;
1082         int err = 0;
1083         u64 blocknr;
1084         u64 extent_start = 0;
1085         u64 extent_end = 0;
1086         u64 objectid = inode->i_ino;
1087         u32 found_type;
1088         struct btrfs_path *path;
1089         struct btrfs_root *root = BTRFS_I(inode)->root;
1090         struct btrfs_file_extent_item *item;
1091         struct btrfs_leaf *leaf;
1092         struct btrfs_disk_key *found_key;
1093
1094         path = btrfs_alloc_path();
1095         BUG_ON(!path);
1096         btrfs_init_path(path);
1097         if (create) {
1098                 WARN_ON(1);
1099         }
1100
1101         ret = btrfs_lookup_file_extent(NULL, root, path,
1102                                        inode->i_ino,
1103                                        iblock << inode->i_blkbits, 0);
1104         if (ret < 0) {
1105                 err = ret;
1106                 goto out;
1107         }
1108
1109         if (ret != 0) {
1110                 if (path->slots[0] == 0) {
1111                         btrfs_release_path(root, path);
1112                         goto out;
1113                 }
1114                 path->slots[0]--;
1115         }
1116
1117         item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
1118                               struct btrfs_file_extent_item);
1119         leaf = btrfs_buffer_leaf(path->nodes[0]);
1120         blocknr = btrfs_file_extent_disk_blocknr(item);
1121         blocknr += btrfs_file_extent_offset(item);
1122
1123         /* are we inside the extent that was found? */
1124         found_key = &leaf->items[path->slots[0]].key;
1125         found_type = btrfs_disk_key_type(found_key);
1126         if (btrfs_disk_key_objectid(found_key) != objectid ||
1127             found_type != BTRFS_EXTENT_DATA_KEY) {
1128                 extent_end = 0;
1129                 extent_start = 0;
1130                 goto out;
1131         }
1132         found_type = btrfs_file_extent_type(item);
1133         extent_start = btrfs_disk_key_offset(&leaf->items[path->slots[0]].key);
1134         if (found_type == BTRFS_FILE_EXTENT_REG) {
1135                 extent_start = extent_start >> inode->i_blkbits;
1136                 extent_end = extent_start + btrfs_file_extent_num_blocks(item);
1137                 if (iblock >= extent_start && iblock < extent_end) {
1138                         err = 0;
1139                         btrfs_map_bh_to_logical(root, result, blocknr +
1140                                                 iblock - extent_start);
1141                         goto out;
1142                 }
1143         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
1144                 char *ptr;
1145                 char *map;
1146                 u32 size;
1147                 size = btrfs_file_extent_inline_len(leaf->items +
1148                                                     path->slots[0]);
1149                 extent_end = (extent_start + size) >> inode->i_blkbits;
1150                 extent_start >>= inode->i_blkbits;
1151                 if (iblock < extent_start || iblock > extent_end) {
1152                         goto out;
1153                 }
1154                 ptr = btrfs_file_extent_inline_start(item);
1155                 map = kmap(result->b_page);
1156                 memcpy(map, ptr, size);
1157                 memset(map + size, 0, PAGE_CACHE_SIZE - size);
1158                 flush_dcache_page(result->b_page);
1159                 kunmap(result->b_page);
1160                 set_buffer_uptodate(result);
1161                 SetPageChecked(result->b_page);
1162                 btrfs_map_bh_to_logical(root, result, 0);
1163         }
1164 out:
1165         btrfs_free_path(path);
1166         return err;
1167 }
1168
1169 static int btrfs_get_block(struct inode *inode, sector_t iblock,
1170                            struct buffer_head *result, int create)
1171 {
1172         int err;
1173         struct btrfs_root *root = BTRFS_I(inode)->root;
1174         mutex_lock(&root->fs_info->fs_mutex);
1175         err = btrfs_get_block_lock(inode, iblock, result, create);
1176         mutex_unlock(&root->fs_info->fs_mutex);
1177         return err;
1178 }
1179
1180 static int btrfs_prepare_write(struct file *file, struct page *page,
1181                                unsigned from, unsigned to)
1182 {
1183         return nobh_prepare_write(page, from, to, btrfs_get_block);
1184 }
1185
1186 static void btrfs_write_super(struct super_block *sb)
1187 {
1188         btrfs_sync_fs(sb, 1);
1189 }
1190
1191 static int btrfs_readpage(struct file *file, struct page *page)
1192 {
1193         return mpage_readpage(page, btrfs_get_block);
1194 }
1195
1196 /*
1197  * While block_write_full_page is writing back the dirty buffers under
1198  * the page lock, whoever dirtied the buffers may decide to clean them
1199  * again at any time.  We handle that by only looking at the buffer
1200  * state inside lock_buffer().
1201  *
1202  * If block_write_full_page() is called for regular writeback
1203  * (wbc->sync_mode == WB_SYNC_NONE) then it will redirty a page which has a
1204  * locked buffer.   This only can happen if someone has written the buffer
1205  * directly, with submit_bh().  At the address_space level PageWriteback
1206  * prevents this contention from occurring.
1207  */
1208 static int __btrfs_write_full_page(struct inode *inode, struct page *page,
1209                                    struct writeback_control *wbc)
1210 {
1211         int err;
1212         sector_t block;
1213         sector_t last_block;
1214         struct buffer_head *bh, *head;
1215         const unsigned blocksize = 1 << inode->i_blkbits;
1216         int nr_underway = 0;
1217
1218         BUG_ON(!PageLocked(page));
1219
1220         last_block = (i_size_read(inode) - 1) >> inode->i_blkbits;
1221
1222         if (!page_has_buffers(page)) {
1223                 create_empty_buffers(page, blocksize,
1224                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
1225         }
1226
1227         /*
1228          * Be very careful.  We have no exclusion from __set_page_dirty_buffers
1229          * here, and the (potentially unmapped) buffers may become dirty at
1230          * any time.  If a buffer becomes dirty here after we've inspected it
1231          * then we just miss that fact, and the page stays dirty.
1232          *
1233          * Buffers outside i_size may be dirtied by __set_page_dirty_buffers;
1234          * handle that here by just cleaning them.
1235          */
1236
1237         block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
1238         head = page_buffers(page);
1239         bh = head;
1240
1241         /*
1242          * Get all the dirty buffers mapped to disk addresses and
1243          * handle any aliases from the underlying blockdev's mapping.
1244          */
1245         do {
1246                 if (block > last_block) {
1247                         /*
1248                          * mapped buffers outside i_size will occur, because
1249                          * this page can be outside i_size when there is a
1250                          * truncate in progress.
1251                          */
1252                         /*
1253                          * The buffer was zeroed by block_write_full_page()
1254                          */
1255                         clear_buffer_dirty(bh);
1256                         set_buffer_uptodate(bh);
1257                 } else if (!buffer_mapped(bh) && buffer_dirty(bh)) {
1258                         WARN_ON(bh->b_size != blocksize);
1259                         err = btrfs_get_block(inode, block, bh, 0);
1260                         if (err) {
1261 printk("writepage going to recovery err %d\n", err);
1262                                 goto recover;
1263                         }
1264                         if (buffer_new(bh)) {
1265                                 /* blockdev mappings never come here */
1266                                 clear_buffer_new(bh);
1267                         }
1268                 }
1269                 bh = bh->b_this_page;
1270                 block++;
1271         } while (bh != head);
1272
1273         do {
1274                 if (!buffer_mapped(bh))
1275                         continue;
1276                 /*
1277                  * If it's a fully non-blocking write attempt and we cannot
1278                  * lock the buffer then redirty the page.  Note that this can
1279                  * potentially cause a busy-wait loop from pdflush and kswapd
1280                  * activity, but those code paths have their own higher-level
1281                  * throttling.
1282                  */
1283                 if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
1284                         lock_buffer(bh);
1285                 } else if (test_set_buffer_locked(bh)) {
1286                         redirty_page_for_writepage(wbc, page);
1287                         continue;
1288                 }
1289                 if (test_clear_buffer_dirty(bh) && bh->b_blocknr != 0) {
1290                         mark_buffer_async_write(bh);
1291                 } else {
1292                         unlock_buffer(bh);
1293                 }
1294         } while ((bh = bh->b_this_page) != head);
1295
1296         /*
1297          * The page and its buffers are protected by PageWriteback(), so we can
1298          * drop the bh refcounts early.
1299          */
1300         BUG_ON(PageWriteback(page));
1301         set_page_writeback(page);
1302
1303         do {
1304                 struct buffer_head *next = bh->b_this_page;
1305                 if (buffer_async_write(bh)) {
1306                         submit_bh(WRITE, bh);
1307                         nr_underway++;
1308                 }
1309                 bh = next;
1310         } while (bh != head);
1311         unlock_page(page);
1312
1313         err = 0;
1314 done:
1315         if (nr_underway == 0) {
1316                 /*
1317                  * The page was marked dirty, but the buffers were
1318                  * clean.  Someone wrote them back by hand with
1319                  * ll_rw_block/submit_bh.  A rare case.
1320                  */
1321                 int uptodate = 1;
1322                 do {
1323                         if (!buffer_uptodate(bh)) {
1324                                 uptodate = 0;
1325                                 break;
1326                         }
1327                         bh = bh->b_this_page;
1328                 } while (bh != head);
1329                 if (uptodate)
1330                         SetPageUptodate(page);
1331                 end_page_writeback(page);
1332         }
1333         return err;
1334
1335 recover:
1336         /*
1337          * ENOSPC, or some other error.  We may already have added some
1338          * blocks to the file, so we need to write these out to avoid
1339          * exposing stale data.
1340          * The page is currently locked and not marked for writeback
1341          */
1342         bh = head;
1343         /* Recovery: lock and submit the mapped buffers */
1344         do {
1345                 if (buffer_mapped(bh) && buffer_dirty(bh)) {
1346                         lock_buffer(bh);
1347                         mark_buffer_async_write(bh);
1348                 } else {
1349                         /*
1350                          * The buffer may have been set dirty during
1351                          * attachment to a dirty page.
1352                          */
1353                         clear_buffer_dirty(bh);
1354                 }
1355         } while ((bh = bh->b_this_page) != head);
1356         SetPageError(page);
1357         BUG_ON(PageWriteback(page));
1358         set_page_writeback(page);
1359         do {
1360                 struct buffer_head *next = bh->b_this_page;
1361                 if (buffer_async_write(bh)) {
1362                         clear_buffer_dirty(bh);
1363                         submit_bh(WRITE, bh);
1364                         nr_underway++;
1365                 }
1366                 bh = next;
1367         } while (bh != head);
1368         unlock_page(page);
1369         goto done;
1370 }
1371
1372 /*
1373  * The generic ->writepage function for buffer-backed address_spaces
1374  */
1375 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
1376 {
1377         struct inode * const inode = page->mapping->host;
1378         loff_t i_size = i_size_read(inode);
1379         const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
1380         unsigned offset;
1381         void *kaddr;
1382
1383         /* Is the page fully inside i_size? */
1384         if (page->index < end_index)
1385                 return __btrfs_write_full_page(inode, page, wbc);
1386
1387         /* Is the page fully outside i_size? (truncate in progress) */
1388         offset = i_size & (PAGE_CACHE_SIZE-1);
1389         if (page->index >= end_index+1 || !offset) {
1390                 /*
1391                  * The page may have dirty, unmapped buffers.  For example,
1392                  * they may have been added in ext3_writepage().  Make them
1393                  * freeable here, so the page does not leak.
1394                  */
1395                 block_invalidatepage(page, 0);
1396                 unlock_page(page);
1397                 return 0; /* don't care */
1398         }
1399
1400         /*
1401          * The page straddles i_size.  It must be zeroed out on each and every
1402          * writepage invokation because it may be mmapped.  "A file is mapped
1403          * in multiples of the page size.  For a file that is not a multiple of
1404          * the  page size, the remaining memory is zeroed when mapped, and
1405          * writes to that region are not written out to the file."
1406          */
1407         kaddr = kmap_atomic(page, KM_USER0);
1408         memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
1409         flush_dcache_page(page);
1410         kunmap_atomic(kaddr, KM_USER0);
1411         return __btrfs_write_full_page(inode, page, wbc);
1412 }
1413
1414 static void btrfs_truncate(struct inode *inode)
1415 {
1416         struct btrfs_root *root = BTRFS_I(inode)->root;
1417         int ret;
1418         struct btrfs_trans_handle *trans;
1419
1420         if (!S_ISREG(inode->i_mode))
1421                 return;
1422         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1423                 return;
1424
1425         nobh_truncate_page(inode->i_mapping, inode->i_size);
1426
1427         /* FIXME, add redo link to tree so we don't leak on crash */
1428         mutex_lock(&root->fs_info->fs_mutex);
1429         trans = btrfs_start_transaction(root, 1);
1430         btrfs_set_trans_block_group(trans, inode);
1431         ret = btrfs_truncate_in_trans(trans, root, inode);
1432         BUG_ON(ret);
1433         btrfs_update_inode(trans, root, inode);
1434         ret = btrfs_end_transaction(trans, root);
1435         BUG_ON(ret);
1436         mutex_unlock(&root->fs_info->fs_mutex);
1437         btrfs_btree_balance_dirty(root);
1438 }
1439
1440 /*
1441  * Make sure any changes to nobh_commit_write() are reflected in
1442  * nobh_truncate_page(), since it doesn't call commit_write().
1443  */
1444 static int btrfs_commit_write(struct file *file, struct page *page,
1445                               unsigned from, unsigned to)
1446 {
1447         struct inode *inode = page->mapping->host;
1448         struct buffer_head *bh;
1449         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
1450
1451         SetPageUptodate(page);
1452         bh = page_buffers(page);
1453         if (buffer_mapped(bh) && bh->b_blocknr != 0) {
1454                 set_page_dirty(page);
1455         }
1456         if (pos > inode->i_size) {
1457                 i_size_write(inode, pos);
1458                 mark_inode_dirty(inode);
1459         }
1460         return 0;
1461 }
1462
1463 static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes,
1464                                 struct page **prepared_pages,
1465                                 const char __user * buf)
1466 {
1467         long page_fault = 0;
1468         int i;
1469         int offset = pos & (PAGE_CACHE_SIZE - 1);
1470
1471         for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
1472                 size_t count = min_t(size_t,
1473                                      PAGE_CACHE_SIZE - offset, write_bytes);
1474                 struct page *page = prepared_pages[i];
1475                 fault_in_pages_readable(buf, count);
1476
1477                 /* Copy data from userspace to the current page */
1478                 kmap(page);
1479                 page_fault = __copy_from_user(page_address(page) + offset,
1480                                               buf, count);
1481                 /* Flush processor's dcache for this page */
1482                 flush_dcache_page(page);
1483                 kunmap(page);
1484                 buf += count;
1485                 write_bytes -= count;
1486
1487                 if (page_fault)
1488                         break;
1489         }
1490         return page_fault ? -EFAULT : 0;
1491 }
1492
1493 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
1494 {
1495         size_t i;
1496         for (i = 0; i < num_pages; i++) {
1497                 if (!pages[i])
1498                         break;
1499                 unlock_page(pages[i]);
1500                 mark_page_accessed(pages[i]);
1501                 page_cache_release(pages[i]);
1502         }
1503 }
1504 static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
1505                                    struct btrfs_root *root,
1506                                    struct file *file,
1507                                    struct page **pages,
1508                                    size_t num_pages,
1509                                    loff_t pos,
1510                                    size_t write_bytes)
1511 {
1512         int i;
1513         int offset;
1514         int err = 0;
1515         int ret;
1516         int this_write;
1517         struct inode *inode = file->f_path.dentry->d_inode;
1518         struct buffer_head *bh;
1519         struct btrfs_file_extent_item *ei;
1520
1521         for (i = 0; i < num_pages; i++) {
1522                 offset = pos & (PAGE_CACHE_SIZE -1);
1523                 this_write = min(PAGE_CACHE_SIZE - offset, write_bytes);
1524                 /* FIXME, one block at a time */
1525
1526                 mutex_lock(&root->fs_info->fs_mutex);
1527                 trans = btrfs_start_transaction(root, 1);
1528                 btrfs_set_trans_block_group(trans, inode);
1529
1530                 bh = page_buffers(pages[i]);
1531                 if (buffer_mapped(bh) && bh->b_blocknr == 0) {
1532                         struct btrfs_key key;
1533                         struct btrfs_path *path;
1534                         char *ptr;
1535                         u32 datasize;
1536
1537                         path = btrfs_alloc_path();
1538                         BUG_ON(!path);
1539                         key.objectid = inode->i_ino;
1540                         key.offset = pages[i]->index << PAGE_CACHE_SHIFT;
1541                         key.flags = 0;
1542                         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
1543                         BUG_ON(write_bytes >= PAGE_CACHE_SIZE);
1544                         datasize = offset +
1545                                 btrfs_file_extent_calc_inline_size(write_bytes);
1546                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1547                                                       datasize);
1548                         BUG_ON(ret);
1549                         ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
1550                                path->slots[0], struct btrfs_file_extent_item);
1551                         btrfs_set_file_extent_generation(ei, trans->transid);
1552                         btrfs_set_file_extent_type(ei,
1553                                                    BTRFS_FILE_EXTENT_INLINE);
1554                         ptr = btrfs_file_extent_inline_start(ei);
1555                         btrfs_memcpy(root, path->nodes[0]->b_data,
1556                                      ptr, bh->b_data, offset + write_bytes);
1557                         mark_buffer_dirty(path->nodes[0]);
1558                         btrfs_free_path(path);
1559                 } else {
1560                         btrfs_csum_file_block(trans, root, inode->i_ino,
1561                                       pages[i]->index << PAGE_CACHE_SHIFT,
1562                                       kmap(pages[i]), PAGE_CACHE_SIZE);
1563                         kunmap(pages[i]);
1564                 }
1565                 SetPageChecked(pages[i]);
1566                 // btrfs_update_inode_block_group(trans, inode);
1567                 ret = btrfs_end_transaction(trans, root);
1568                 BUG_ON(ret);
1569                 mutex_unlock(&root->fs_info->fs_mutex);
1570
1571                 ret = btrfs_commit_write(file, pages[i], offset,
1572                                          offset + this_write);
1573                 pos += this_write;
1574                 if (ret) {
1575                         err = ret;
1576                         goto failed;
1577                 }
1578                 WARN_ON(this_write > write_bytes);
1579                 write_bytes -= this_write;
1580         }
1581 failed:
1582         return err;
1583 }
1584
1585 static int drop_extents(struct btrfs_trans_handle *trans,
1586                           struct btrfs_root *root,
1587                           struct inode *inode,
1588                           u64 start, u64 end, u64 *hint_block)
1589 {
1590         int ret;
1591         struct btrfs_key key;
1592         struct btrfs_leaf *leaf;
1593         int slot;
1594         struct btrfs_file_extent_item *extent;
1595         u64 extent_end = 0;
1596         int keep;
1597         struct btrfs_file_extent_item old;
1598         struct btrfs_path *path;
1599         u64 search_start = start;
1600         int bookend;
1601         int found_type;
1602         int found_extent;
1603         int found_inline;
1604
1605         path = btrfs_alloc_path();
1606         if (!path)
1607                 return -ENOMEM;
1608         while(1) {
1609                 btrfs_release_path(root, path);
1610                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
1611                                                search_start, -1);
1612                 if (ret < 0)
1613                         goto out;
1614                 if (ret > 0) {
1615                         if (path->slots[0] == 0) {
1616                                 ret = 0;
1617                                 goto out;
1618                         }
1619                         path->slots[0]--;
1620                 }
1621                 keep = 0;
1622                 bookend = 0;
1623                 found_extent = 0;
1624                 found_inline = 0;
1625                 extent = NULL;
1626                 leaf = btrfs_buffer_leaf(path->nodes[0]);
1627                 slot = path->slots[0];
1628                 btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
1629                 if (key.offset >= end || key.objectid != inode->i_ino) {
1630                         ret = 0;
1631                         goto out;
1632                 }
1633                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY) {
1634                         ret = 0;
1635                         goto out;
1636                 }
1637                 extent = btrfs_item_ptr(leaf, slot,
1638                                         struct btrfs_file_extent_item);
1639                 found_type = btrfs_file_extent_type(extent);
1640                 if (found_type == BTRFS_FILE_EXTENT_REG) {
1641                         extent_end = key.offset +
1642                                 (btrfs_file_extent_num_blocks(extent) <<
1643                                  inode->i_blkbits);
1644                         found_extent = 1;
1645                 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
1646                         found_inline = 1;
1647                         extent_end = key.offset +
1648                              btrfs_file_extent_inline_len(leaf->items + slot);
1649                 }
1650
1651                 if (!found_extent && !found_inline) {
1652                         ret = 0;
1653                         goto out;
1654                 }
1655
1656                 if (search_start >= extent_end) {
1657                         ret = 0;
1658                         goto out;
1659                 }
1660
1661                 search_start = extent_end;
1662
1663                 if (end < extent_end && end >= key.offset) {
1664                         if (found_extent) {
1665                                 memcpy(&old, extent, sizeof(old));
1666                                 ret = btrfs_inc_extent_ref(trans, root,
1667                                       btrfs_file_extent_disk_blocknr(&old),
1668                                       btrfs_file_extent_disk_num_blocks(&old));
1669                                 BUG_ON(ret);
1670                         }
1671                         WARN_ON(found_inline);
1672                         bookend = 1;
1673                 }
1674
1675                 if (start > key.offset) {
1676                         u64 new_num;
1677                         u64 old_num;
1678                         /* truncate existing extent */
1679                         keep = 1;
1680                         WARN_ON(start & (root->blocksize - 1));
1681                         if (found_extent) {
1682                                 new_num = (start - key.offset) >>
1683                                         inode->i_blkbits;
1684                                 old_num = btrfs_file_extent_num_blocks(extent);
1685                                 *hint_block =
1686                                         btrfs_file_extent_disk_blocknr(extent);
1687                                 inode->i_blocks -= (old_num - new_num) << 3;
1688                                 btrfs_set_file_extent_num_blocks(extent,
1689                                                                  new_num);
1690                                 mark_buffer_dirty(path->nodes[0]);
1691                         } else {
1692                                 WARN_ON(1);
1693                         }
1694                 }
1695                 if (!keep) {
1696                         u64 disk_blocknr = 0;
1697                         u64 disk_num_blocks = 0;
1698                         u64 extent_num_blocks = 0;
1699                         if (found_extent) {
1700                                 disk_blocknr =
1701                                       btrfs_file_extent_disk_blocknr(extent);
1702                                 disk_num_blocks =
1703                                       btrfs_file_extent_disk_num_blocks(extent);
1704                                 extent_num_blocks =
1705                                       btrfs_file_extent_num_blocks(extent);
1706                                 *hint_block =
1707                                         btrfs_file_extent_disk_blocknr(extent);
1708                         }
1709                         ret = btrfs_del_item(trans, root, path);
1710                         BUG_ON(ret);
1711                         btrfs_release_path(root, path);
1712                         extent = NULL;
1713                         if (found_extent) {
1714                                 inode->i_blocks -= extent_num_blocks << 3;
1715                                 ret = btrfs_free_extent(trans, root,
1716                                                         disk_blocknr,
1717                                                         disk_num_blocks, 0);
1718                         }
1719
1720                         BUG_ON(ret);
1721                         if (!bookend && search_start >= end) {
1722                                 ret = 0;
1723                                 goto out;
1724                         }
1725                         if (!bookend)
1726                                 continue;
1727                 }
1728                 if (bookend && found_extent) {
1729                         /* create bookend */
1730                         struct btrfs_key ins;
1731                         ins.objectid = inode->i_ino;
1732                         ins.offset = end;
1733                         ins.flags = 0;
1734                         btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
1735
1736                         btrfs_release_path(root, path);
1737                         ret = btrfs_insert_empty_item(trans, root, path, &ins,
1738                                                       sizeof(*extent));
1739                         BUG_ON(ret);
1740                         extent = btrfs_item_ptr(
1741                                     btrfs_buffer_leaf(path->nodes[0]),
1742                                     path->slots[0],
1743                                     struct btrfs_file_extent_item);
1744                         btrfs_set_file_extent_disk_blocknr(extent,
1745                                     btrfs_file_extent_disk_blocknr(&old));
1746                         btrfs_set_file_extent_disk_num_blocks(extent,
1747                                     btrfs_file_extent_disk_num_blocks(&old));
1748
1749                         btrfs_set_file_extent_offset(extent,
1750                                     btrfs_file_extent_offset(&old) +
1751                                     ((end - key.offset) >> inode->i_blkbits));
1752                         WARN_ON(btrfs_file_extent_num_blocks(&old) <
1753                                 (end - key.offset) >> inode->i_blkbits);
1754                         btrfs_set_file_extent_num_blocks(extent,
1755                                     btrfs_file_extent_num_blocks(&old) -
1756                                     ((end - key.offset) >> inode->i_blkbits));
1757
1758                         btrfs_set_file_extent_type(extent,
1759                                                    BTRFS_FILE_EXTENT_REG);
1760                         btrfs_set_file_extent_generation(extent,
1761                                     btrfs_file_extent_generation(&old));
1762                         btrfs_mark_buffer_dirty(path->nodes[0]);
1763                         inode->i_blocks +=
1764                                 btrfs_file_extent_num_blocks(extent) << 3;
1765                         ret = 0;
1766                         goto out;
1767                 }
1768         }
1769 out:
1770         btrfs_free_path(path);
1771         return ret;
1772 }
1773
1774 static int prepare_pages(struct btrfs_root *root,
1775                          struct file *file,
1776                          struct page **pages,
1777                          size_t num_pages,
1778                          loff_t pos,
1779                          unsigned long first_index,
1780                          unsigned long last_index,
1781                          size_t write_bytes,
1782                          u64 alloc_extent_start)
1783 {
1784         int i;
1785         unsigned long index = pos >> PAGE_CACHE_SHIFT;
1786         struct inode *inode = file->f_path.dentry->d_inode;
1787         int offset;
1788         int err = 0;
1789         int this_write;
1790         struct buffer_head *bh;
1791         struct buffer_head *head;
1792         loff_t isize = i_size_read(inode);
1793
1794         memset(pages, 0, num_pages * sizeof(struct page *));
1795
1796         for (i = 0; i < num_pages; i++) {
1797                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
1798                 if (!pages[i]) {
1799                         err = -ENOMEM;
1800                         goto failed_release;
1801                 }
1802                 cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
1803                 wait_on_page_writeback(pages[i]);
1804                 offset = pos & (PAGE_CACHE_SIZE -1);
1805                 this_write = min(PAGE_CACHE_SIZE - offset, write_bytes);
1806                 if (!page_has_buffers(pages[i])) {
1807                         create_empty_buffers(pages[i],
1808                                              root->fs_info->sb->s_blocksize,
1809                                              (1 << BH_Uptodate));
1810                 }
1811                 head = page_buffers(pages[i]);
1812                 bh = head;
1813                 do {
1814                         err = btrfs_map_bh_to_logical(root, bh,
1815                                                       alloc_extent_start);
1816                         BUG_ON(err);
1817                         if (err)
1818                                 goto failed_truncate;
1819                         bh = bh->b_this_page;
1820                         if (alloc_extent_start)
1821                                 alloc_extent_start++;
1822                 } while (bh != head);
1823                 pos += this_write;
1824                 WARN_ON(this_write > write_bytes);
1825                 write_bytes -= this_write;
1826         }
1827         return 0;
1828
1829 failed_release:
1830         btrfs_drop_pages(pages, num_pages);
1831         return err;
1832
1833 failed_truncate:
1834         btrfs_drop_pages(pages, num_pages);
1835         if (pos > isize)
1836                 vmtruncate(inode, isize);
1837         return err;
1838 }
1839
1840 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
1841                                 size_t count, loff_t *ppos)
1842 {
1843         loff_t pos;
1844         size_t num_written = 0;
1845         int err = 0;
1846         int ret = 0;
1847         struct inode *inode = file->f_path.dentry->d_inode;
1848         struct btrfs_root *root = BTRFS_I(inode)->root;
1849         struct page *pages[8];
1850         struct page *pinned[2];
1851         unsigned long first_index;
1852         unsigned long last_index;
1853         u64 start_pos;
1854         u64 num_blocks;
1855         u64 alloc_extent_start;
1856         u64 hint_block;
1857         struct btrfs_trans_handle *trans;
1858         struct btrfs_key ins;
1859         pinned[0] = NULL;
1860         pinned[1] = NULL;
1861         if (file->f_flags & O_DIRECT)
1862                 return -EINVAL;
1863         pos = *ppos;
1864         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1865         current->backing_dev_info = inode->i_mapping->backing_dev_info;
1866         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1867         if (err)
1868                 goto out;
1869         if (count == 0)
1870                 goto out;
1871         err = remove_suid(file->f_path.dentry);
1872         if (err)
1873                 goto out;
1874         file_update_time(file);
1875
1876         start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
1877         num_blocks = (count + pos - start_pos + root->blocksize - 1) >>
1878                         inode->i_blkbits;
1879
1880         mutex_lock(&inode->i_mutex);
1881         first_index = pos >> PAGE_CACHE_SHIFT;
1882         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
1883
1884         if ((first_index << PAGE_CACHE_SHIFT) < inode->i_size &&
1885             (pos & (PAGE_CACHE_SIZE - 1))) {
1886                 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
1887                 if (!PageUptodate(pinned[0])) {
1888                         ret = mpage_readpage(pinned[0], btrfs_get_block);
1889                         BUG_ON(ret);
1890                         wait_on_page_locked(pinned[0]);
1891                 } else {
1892                         unlock_page(pinned[0]);
1893                 }
1894         }
1895         if (first_index != last_index &&
1896             (last_index << PAGE_CACHE_SHIFT) < inode->i_size &&
1897             pos + count < inode->i_size &&
1898             (count & (PAGE_CACHE_SIZE - 1))) {
1899                 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
1900                 if (!PageUptodate(pinned[1])) {
1901                         ret = mpage_readpage(pinned[1], btrfs_get_block);
1902                         BUG_ON(ret);
1903                         wait_on_page_locked(pinned[1]);
1904                 } else {
1905                         unlock_page(pinned[1]);
1906                 }
1907         }
1908
1909         mutex_lock(&root->fs_info->fs_mutex);
1910         trans = btrfs_start_transaction(root, 1);
1911         if (!trans) {
1912                 err = -ENOMEM;
1913                 mutex_unlock(&root->fs_info->fs_mutex);
1914                 goto out_unlock;
1915         }
1916         btrfs_set_trans_block_group(trans, inode);
1917         /* FIXME blocksize != 4096 */
1918         inode->i_blocks += num_blocks << 3;
1919         hint_block = 0;
1920         if (start_pos < inode->i_size) {
1921                 /* FIXME blocksize != pagesize */
1922                 ret = drop_extents(trans, root, inode,
1923                                    start_pos,
1924                                    (pos + count + root->blocksize -1) &
1925                                    ~((u64)root->blocksize - 1), &hint_block);
1926                 BUG_ON(ret);
1927         }
1928         if (inode->i_size >= PAGE_CACHE_SIZE || pos + count < inode->i_size ||
1929             pos + count - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
1930                 ret = btrfs_alloc_extent(trans, root, inode->i_ino,
1931                                          num_blocks, hint_block, (u64)-1,
1932                                          &ins, 1);
1933                 BUG_ON(ret);
1934                 ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
1935                                        start_pos, ins.objectid, ins.offset);
1936                 BUG_ON(ret);
1937         } else {
1938                 ins.offset = 0;
1939                 ins.objectid = 0;
1940         }
1941         BUG_ON(ret);
1942         alloc_extent_start = ins.objectid;
1943         // btrfs_update_inode_block_group(trans, inode);
1944         ret = btrfs_end_transaction(trans, root);
1945         mutex_unlock(&root->fs_info->fs_mutex);
1946
1947         while(count > 0) {
1948                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1949                 size_t write_bytes = min(count, PAGE_CACHE_SIZE - offset);
1950                 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
1951                                         PAGE_CACHE_SHIFT;
1952
1953                 memset(pages, 0, sizeof(pages));
1954                 ret = prepare_pages(root, file, pages, num_pages,
1955                                     pos, first_index, last_index,
1956                                     write_bytes, alloc_extent_start);
1957                 BUG_ON(ret);
1958
1959                 /* FIXME blocks != pagesize */
1960                 if (alloc_extent_start)
1961                         alloc_extent_start += num_pages;
1962                 ret = btrfs_copy_from_user(pos, num_pages,
1963                                            write_bytes, pages, buf);
1964                 BUG_ON(ret);
1965
1966                 ret = dirty_and_release_pages(NULL, root, file, pages,
1967                                               num_pages, pos, write_bytes);
1968                 BUG_ON(ret);
1969                 btrfs_drop_pages(pages, num_pages);
1970
1971                 buf += write_bytes;
1972                 count -= write_bytes;
1973                 pos += write_bytes;
1974                 num_written += write_bytes;
1975
1976                 balance_dirty_pages_ratelimited(inode->i_mapping);
1977                 btrfs_btree_balance_dirty(root);
1978                 cond_resched();
1979         }
1980 out_unlock:
1981         mutex_unlock(&inode->i_mutex);
1982 out:
1983         if (pinned[0])
1984                 page_cache_release(pinned[0]);
1985         if (pinned[1])
1986                 page_cache_release(pinned[1]);
1987         *ppos = pos;
1988         current->backing_dev_info = NULL;
1989         mark_inode_dirty(inode);
1990         return num_written ? num_written : err;
1991 }
1992
1993 static int btrfs_read_actor(read_descriptor_t *desc, struct page *page,
1994                         unsigned long offset, unsigned long size)
1995 {
1996         char *kaddr;
1997         unsigned long left, count = desc->count;
1998         struct inode *inode = page->mapping->host;
1999
2000         if (size > count)
2001                 size = count;
2002
2003         if (!PageChecked(page)) {
2004                 /* FIXME, do it per block */
2005                 struct btrfs_root *root = BTRFS_I(inode)->root;
2006
2007                 int ret = btrfs_csum_verify_file_block(root,
2008                                   page->mapping->host->i_ino,
2009                                   page->index << PAGE_CACHE_SHIFT,
2010                                   kmap(page), PAGE_CACHE_SIZE);
2011                 if (ret) {
2012                         printk("failed to verify ino %lu page %lu\n",
2013                                page->mapping->host->i_ino,
2014                                page->index);
2015                         memset(page_address(page), 0, PAGE_CACHE_SIZE);
2016                 }
2017                 SetPageChecked(page);
2018                 kunmap(page);
2019         }
2020         /*
2021          * Faults on the destination of a read are common, so do it before
2022          * taking the kmap.
2023          */
2024         if (!fault_in_pages_writeable(desc->arg.buf, size)) {
2025                 kaddr = kmap_atomic(page, KM_USER0);
2026                 left = __copy_to_user_inatomic(desc->arg.buf,
2027                                                 kaddr + offset, size);
2028                 kunmap_atomic(kaddr, KM_USER0);
2029                 if (left == 0)
2030                         goto success;
2031         }
2032
2033         /* Do it the slow way */
2034         kaddr = kmap(page);
2035         left = __copy_to_user(desc->arg.buf, kaddr + offset, size);
2036         kunmap(page);
2037
2038         if (left) {
2039                 size -= left;
2040                 desc->error = -EFAULT;
2041         }
2042 success:
2043         desc->count = count - size;
2044         desc->written += size;
2045         desc->arg.buf += size;
2046         return size;
2047 }
2048
2049 /**
2050  * btrfs_file_aio_read - filesystem read routine
2051  * @iocb:       kernel I/O control block
2052  * @iov:        io vector request
2053  * @nr_segs:    number of segments in the iovec
2054  * @pos:        current file position
2055  */
2056 static ssize_t btrfs_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
2057                                    unsigned long nr_segs, loff_t pos)
2058 {
2059         struct file *filp = iocb->ki_filp;
2060         ssize_t retval;
2061         unsigned long seg;
2062         size_t count;
2063         loff_t *ppos = &iocb->ki_pos;
2064
2065         count = 0;
2066         for (seg = 0; seg < nr_segs; seg++) {
2067                 const struct iovec *iv = &iov[seg];
2068
2069                 /*
2070                  * If any segment has a negative length, or the cumulative
2071                  * length ever wraps negative then return -EINVAL.
2072                  */
2073                 count += iv->iov_len;
2074                 if (unlikely((ssize_t)(count|iv->iov_len) < 0))
2075                         return -EINVAL;
2076                 if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len))
2077                         continue;
2078                 if (seg == 0)
2079                         return -EFAULT;
2080                 nr_segs = seg;
2081                 count -= iv->iov_len;   /* This segment is no good */
2082                 break;
2083         }
2084         retval = 0;
2085         if (count) {
2086                 for (seg = 0; seg < nr_segs; seg++) {
2087                         read_descriptor_t desc;
2088
2089                         desc.written = 0;
2090                         desc.arg.buf = iov[seg].iov_base;
2091                         desc.count = iov[seg].iov_len;
2092                         if (desc.count == 0)
2093                                 continue;
2094                         desc.error = 0;
2095                         do_generic_file_read(filp, ppos, &desc,
2096                                              btrfs_read_actor);
2097                         retval += desc.written;
2098                         if (desc.error) {
2099                                 retval = retval ?: desc.error;
2100                                 break;
2101                         }
2102                 }
2103         }
2104         return retval;
2105 }
2106
2107 static int create_subvol(struct btrfs_root *root, char *name, int namelen)
2108 {
2109         struct btrfs_trans_handle *trans;
2110         struct btrfs_key key;
2111         struct btrfs_root_item root_item;
2112         struct btrfs_inode_item *inode_item;
2113         struct buffer_head *subvol;
2114         struct btrfs_leaf *leaf;
2115         struct btrfs_root *new_root;
2116         struct inode *inode;
2117         struct inode *dir;
2118         int ret;
2119         u64 objectid;
2120         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
2121
2122         mutex_lock(&root->fs_info->fs_mutex);
2123         trans = btrfs_start_transaction(root, 1);
2124         BUG_ON(!trans);
2125
2126         subvol = btrfs_alloc_free_block(trans, root, 0);
2127         if (subvol == NULL)
2128                 return -ENOSPC;
2129         leaf = btrfs_buffer_leaf(subvol);
2130         btrfs_set_header_nritems(&leaf->header, 0);
2131         btrfs_set_header_level(&leaf->header, 0);
2132         btrfs_set_header_blocknr(&leaf->header, bh_blocknr(subvol));
2133         btrfs_set_header_generation(&leaf->header, trans->transid);
2134         btrfs_set_header_owner(&leaf->header, root->root_key.objectid);
2135         memcpy(leaf->header.fsid, root->fs_info->disk_super->fsid,
2136                sizeof(leaf->header.fsid));
2137         mark_buffer_dirty(subvol);
2138
2139         inode_item = &root_item.inode;
2140         memset(inode_item, 0, sizeof(*inode_item));
2141         btrfs_set_inode_generation(inode_item, 1);
2142         btrfs_set_inode_size(inode_item, 3);
2143         btrfs_set_inode_nlink(inode_item, 1);
2144         btrfs_set_inode_nblocks(inode_item, 1);
2145         btrfs_set_inode_mode(inode_item, S_IFDIR | 0755);
2146
2147         btrfs_set_root_blocknr(&root_item, bh_blocknr(subvol));
2148         btrfs_set_root_refs(&root_item, 1);
2149         brelse(subvol);
2150         subvol = NULL;
2151
2152         ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
2153                                        0, &objectid);
2154         BUG_ON(ret);
2155
2156         btrfs_set_root_dirid(&root_item, new_dirid);
2157
2158         key.objectid = objectid;
2159         key.offset = 1;
2160         key.flags = 0;
2161         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
2162         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
2163                                 &root_item);
2164         BUG_ON(ret);
2165
2166         /*
2167          * insert the directory item
2168          */
2169         key.offset = (u64)-1;
2170         dir = root->fs_info->sb->s_root->d_inode;
2171         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
2172                                     name, namelen, dir->i_ino, &key, 0);
2173         BUG_ON(ret);
2174
2175         ret = btrfs_commit_transaction(trans, root);
2176         BUG_ON(ret);
2177
2178         new_root = btrfs_read_fs_root(root->fs_info, &key);
2179         BUG_ON(!new_root);
2180
2181         trans = btrfs_start_transaction(new_root, 1);
2182         BUG_ON(!trans);
2183
2184         inode = btrfs_new_inode(trans, new_root, new_dirid,
2185                                 BTRFS_I(dir)->block_group, S_IFDIR | 0700);
2186         inode->i_op = &btrfs_dir_inode_operations;
2187         inode->i_fop = &btrfs_dir_file_operations;
2188
2189         ret = btrfs_make_empty_dir(trans, new_root, new_dirid, new_dirid);
2190         BUG_ON(ret);
2191
2192         inode->i_nlink = 1;
2193         inode->i_size = 6;
2194         ret = btrfs_update_inode(trans, new_root, inode);
2195         BUG_ON(ret);
2196
2197         ret = btrfs_commit_transaction(trans, new_root);
2198         BUG_ON(ret);
2199
2200         iput(inode);
2201
2202         mutex_unlock(&root->fs_info->fs_mutex);
2203         btrfs_btree_balance_dirty(root);
2204         return 0;
2205 }
2206
2207 static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
2208 {
2209         struct btrfs_trans_handle *trans;
2210         struct btrfs_key key;
2211         struct btrfs_root_item new_root_item;
2212         int ret;
2213         u64 objectid;
2214
2215         if (!root->ref_cows)
2216                 return -EINVAL;
2217
2218         mutex_lock(&root->fs_info->fs_mutex);
2219         trans = btrfs_start_transaction(root, 1);
2220         BUG_ON(!trans);
2221
2222         ret = btrfs_update_inode(trans, root, root->inode);
2223         BUG_ON(ret);
2224
2225         ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
2226                                        0, &objectid);
2227         BUG_ON(ret);
2228
2229         memcpy(&new_root_item, &root->root_item,
2230                sizeof(new_root_item));
2231
2232         key.objectid = objectid;
2233         key.offset = 1;
2234         key.flags = 0;
2235         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
2236         btrfs_set_root_blocknr(&new_root_item, bh_blocknr(root->node));
2237
2238         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
2239                                 &new_root_item);
2240         BUG_ON(ret);
2241
2242         /*
2243          * insert the directory item
2244          */
2245         key.offset = (u64)-1;
2246         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
2247                                     name, namelen,
2248                                     root->fs_info->sb->s_root->d_inode->i_ino,
2249                                     &key, 0);
2250
2251         BUG_ON(ret);
2252
2253         ret = btrfs_inc_root_ref(trans, root);
2254         BUG_ON(ret);
2255
2256         ret = btrfs_commit_transaction(trans, root);
2257         BUG_ON(ret);
2258         mutex_unlock(&root->fs_info->fs_mutex);
2259         btrfs_btree_balance_dirty(root);
2260         return 0;
2261 }
2262
2263 static int add_disk(struct btrfs_root *root, char *name, int namelen)
2264 {
2265         struct block_device *bdev;
2266         struct btrfs_path *path;
2267         struct super_block *sb = root->fs_info->sb;
2268         struct btrfs_root *dev_root = root->fs_info->dev_root;
2269         struct btrfs_trans_handle *trans;
2270         struct btrfs_device_item *dev_item;
2271         struct btrfs_key key;
2272         u16 item_size;
2273         u64 num_blocks;
2274         u64 new_blocks;
2275         u64 device_id;
2276         int ret;
2277
2278 printk("adding disk %s\n", name);
2279         path = btrfs_alloc_path();
2280         if (!path)
2281                 return -ENOMEM;
2282         num_blocks = btrfs_super_total_blocks(root->fs_info->disk_super);
2283         bdev = open_bdev_excl(name, O_RDWR, sb);
2284         if (IS_ERR(bdev)) {
2285                 ret = PTR_ERR(bdev);
2286 printk("open bdev excl failed ret %d\n", ret);
2287                 goto out_nolock;
2288         }
2289         set_blocksize(bdev, sb->s_blocksize);
2290         new_blocks = bdev->bd_inode->i_size >> sb->s_blocksize_bits;
2291         key.objectid = num_blocks;
2292         key.offset = new_blocks;
2293         key.flags = 0;
2294         btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
2295
2296         mutex_lock(&dev_root->fs_info->fs_mutex);
2297         trans = btrfs_start_transaction(dev_root, 1);
2298         item_size = sizeof(*dev_item) + namelen;
2299 printk("insert empty on %Lu %Lu %u size %d\n", num_blocks, new_blocks, key.flags, item_size);
2300         ret = btrfs_insert_empty_item(trans, dev_root, path, &key, item_size);
2301         if (ret) {
2302 printk("insert failed %d\n", ret);
2303                 close_bdev_excl(bdev);
2304                 if (ret > 0)
2305                         ret = -EEXIST;
2306                 goto out;
2307         }
2308         dev_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
2309                                   path->slots[0], struct btrfs_device_item);
2310         btrfs_set_device_pathlen(dev_item, namelen);
2311         memcpy(dev_item + 1, name, namelen);
2312
2313         device_id = btrfs_super_last_device_id(root->fs_info->disk_super) + 1;
2314         btrfs_set_super_last_device_id(root->fs_info->disk_super, device_id);
2315         btrfs_set_device_id(dev_item, device_id);
2316         mark_buffer_dirty(path->nodes[0]);
2317
2318         ret = btrfs_insert_dev_radix(root, bdev, device_id, num_blocks,
2319                                      new_blocks);
2320
2321         if (!ret) {
2322                 btrfs_set_super_total_blocks(root->fs_info->disk_super,
2323                                              num_blocks + new_blocks);
2324                 i_size_write(root->fs_info->btree_inode,
2325                              (num_blocks + new_blocks) <<
2326                              root->fs_info->btree_inode->i_blkbits);
2327         }
2328
2329 out:
2330         ret = btrfs_commit_transaction(trans, dev_root);
2331         BUG_ON(ret);
2332         mutex_unlock(&root->fs_info->fs_mutex);
2333 out_nolock:
2334         btrfs_free_path(path);
2335         btrfs_btree_balance_dirty(root);
2336
2337         return ret;
2338 }
2339
2340 static int btrfs_ioctl(struct inode *inode, struct file *filp, unsigned int
2341                        cmd, unsigned long arg)
2342 {
2343         struct btrfs_root *root = BTRFS_I(inode)->root;
2344         struct btrfs_ioctl_vol_args vol_args;
2345         int ret = 0;
2346         struct btrfs_dir_item *di;
2347         int namelen;
2348         struct btrfs_path *path;
2349         u64 root_dirid;
2350
2351         switch (cmd) {
2352         case BTRFS_IOC_SNAP_CREATE:
2353                 if (copy_from_user(&vol_args,
2354                                    (struct btrfs_ioctl_vol_args __user *)arg,
2355                                    sizeof(vol_args)))
2356                         return -EFAULT;
2357                 namelen = strlen(vol_args.name);
2358                 if (namelen > BTRFS_VOL_NAME_MAX)
2359                         return -EINVAL;
2360                 path = btrfs_alloc_path();
2361                 if (!path)
2362                         return -ENOMEM;
2363                 root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
2364                 mutex_lock(&root->fs_info->fs_mutex);
2365                 di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
2366                                     path, root_dirid,
2367                                     vol_args.name, namelen, 0);
2368                 mutex_unlock(&root->fs_info->fs_mutex);
2369                 btrfs_free_path(path);
2370                 if (di && !IS_ERR(di))
2371                         return -EEXIST;
2372
2373                 if (root == root->fs_info->tree_root)
2374                         ret = create_subvol(root, vol_args.name, namelen);
2375                 else
2376                         ret = create_snapshot(root, vol_args.name, namelen);
2377                 WARN_ON(ret);
2378                 break;
2379         case BTRFS_IOC_ADD_DISK:
2380                 if (copy_from_user(&vol_args,
2381                                    (struct btrfs_ioctl_vol_args __user *)arg,
2382                                    sizeof(vol_args)))
2383                         return -EFAULT;
2384                 namelen = strlen(vol_args.name);
2385                 if (namelen > BTRFS_VOL_NAME_MAX)
2386                         return -EINVAL;
2387                 vol_args.name[namelen] = '\0';
2388                 ret = add_disk(root, vol_args.name, namelen);
2389                 break;
2390         default:
2391                 return -ENOTTY;
2392         }
2393         return ret;
2394 }
2395
2396 static struct kmem_cache *btrfs_inode_cachep;
2397 struct kmem_cache *btrfs_trans_handle_cachep;
2398 struct kmem_cache *btrfs_transaction_cachep;
2399 struct kmem_cache *btrfs_bit_radix_cachep;
2400 struct kmem_cache *btrfs_path_cachep;
2401
2402 /*
2403  * Called inside transaction, so use GFP_NOFS
2404  */
2405 static struct inode *btrfs_alloc_inode(struct super_block *sb)
2406 {
2407         struct btrfs_inode *ei;
2408
2409         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
2410         if (!ei)
2411                 return NULL;
2412         return &ei->vfs_inode;
2413 }
2414
2415 static void btrfs_destroy_inode(struct inode *inode)
2416 {
2417         WARN_ON(!list_empty(&inode->i_dentry));
2418         WARN_ON(inode->i_data.nrpages);
2419
2420         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
2421 }
2422
2423 static void init_once(void * foo, struct kmem_cache * cachep,
2424                       unsigned long flags)
2425 {
2426         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
2427
2428         if ((flags & (SLAB_CTOR_CONSTRUCTOR)) ==
2429             SLAB_CTOR_CONSTRUCTOR) {
2430                 inode_init_once(&ei->vfs_inode);
2431         }
2432 }
2433
2434 static int init_inodecache(void)
2435 {
2436         btrfs_inode_cachep = kmem_cache_create("btrfs_inode_cache",
2437                                              sizeof(struct btrfs_inode),
2438                                              0, (SLAB_RECLAIM_ACCOUNT|
2439                                                 SLAB_MEM_SPREAD),
2440                                              init_once, NULL);
2441         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle_cache",
2442                                              sizeof(struct btrfs_trans_handle),
2443                                              0, (SLAB_RECLAIM_ACCOUNT|
2444                                                 SLAB_MEM_SPREAD),
2445                                              NULL, NULL);
2446         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction_cache",
2447                                              sizeof(struct btrfs_transaction),
2448                                              0, (SLAB_RECLAIM_ACCOUNT|
2449                                                 SLAB_MEM_SPREAD),
2450                                              NULL, NULL);
2451         btrfs_path_cachep = kmem_cache_create("btrfs_path_cache",
2452                                              sizeof(struct btrfs_transaction),
2453                                              0, (SLAB_RECLAIM_ACCOUNT|
2454                                                 SLAB_MEM_SPREAD),
2455                                              NULL, NULL);
2456         btrfs_bit_radix_cachep = kmem_cache_create("btrfs_radix",
2457                                              256,
2458                                              0, (SLAB_RECLAIM_ACCOUNT|
2459                                                 SLAB_MEM_SPREAD |
2460                                                 SLAB_DESTROY_BY_RCU),
2461                                              NULL, NULL);
2462         if (btrfs_inode_cachep == NULL || btrfs_trans_handle_cachep == NULL ||
2463             btrfs_transaction_cachep == NULL || btrfs_bit_radix_cachep == NULL)
2464                 return -ENOMEM;
2465         return 0;
2466 }
2467
2468 static void destroy_inodecache(void)
2469 {
2470         kmem_cache_destroy(btrfs_inode_cachep);
2471         kmem_cache_destroy(btrfs_trans_handle_cachep);
2472         kmem_cache_destroy(btrfs_transaction_cachep);
2473         kmem_cache_destroy(btrfs_bit_radix_cachep);
2474         kmem_cache_destroy(btrfs_path_cachep);
2475 }
2476
2477 static int btrfs_get_sb(struct file_system_type *fs_type,
2478         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
2479 {
2480         return get_sb_bdev(fs_type, flags, dev_name, data,
2481                            btrfs_fill_super, mnt);
2482 }
2483
2484 static int btrfs_getattr(struct vfsmount *mnt,
2485                          struct dentry *dentry, struct kstat *stat)
2486 {
2487         struct inode *inode = dentry->d_inode;
2488         generic_fillattr(inode, stat);
2489         stat->blksize = 256 * 1024;
2490         return 0;
2491 }
2492
2493 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2494 {
2495         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
2496         struct btrfs_super_block *disk_super = root->fs_info->disk_super;
2497
2498         buf->f_namelen = BTRFS_NAME_LEN;
2499         buf->f_blocks = btrfs_super_total_blocks(disk_super);
2500         buf->f_bfree = buf->f_blocks - btrfs_super_blocks_used(disk_super);
2501         buf->f_bavail = buf->f_bfree;
2502         buf->f_bsize = dentry->d_sb->s_blocksize;
2503         buf->f_type = BTRFS_SUPER_MAGIC;
2504         return 0;
2505 }
2506
2507 static struct file_system_type btrfs_fs_type = {
2508         .owner          = THIS_MODULE,
2509         .name           = "btrfs",
2510         .get_sb         = btrfs_get_sb,
2511         .kill_sb        = kill_block_super,
2512         .fs_flags       = FS_REQUIRES_DEV,
2513 };
2514
2515 static struct super_operations btrfs_super_ops = {
2516         .delete_inode   = btrfs_delete_inode,
2517         .put_super      = btrfs_put_super,
2518         .read_inode     = btrfs_read_locked_inode,
2519         .write_super    = btrfs_write_super,
2520         .sync_fs        = btrfs_sync_fs,
2521         .write_inode    = btrfs_write_inode,
2522         .dirty_inode    = btrfs_dirty_inode,
2523         .alloc_inode    = btrfs_alloc_inode,
2524         .destroy_inode  = btrfs_destroy_inode,
2525         .statfs         = btrfs_statfs,
2526 };
2527
2528 static struct inode_operations btrfs_dir_inode_operations = {
2529         .lookup         = btrfs_lookup,
2530         .create         = btrfs_create,
2531         .unlink         = btrfs_unlink,
2532         .mkdir          = btrfs_mkdir,
2533         .rmdir          = btrfs_rmdir,
2534 };
2535
2536 static struct inode_operations btrfs_dir_ro_inode_operations = {
2537         .lookup         = btrfs_lookup,
2538 };
2539
2540 static struct file_operations btrfs_dir_file_operations = {
2541         .llseek         = generic_file_llseek,
2542         .read           = generic_read_dir,
2543         .readdir        = btrfs_readdir,
2544         .ioctl          = btrfs_ioctl,
2545 };
2546
2547 static struct address_space_operations btrfs_aops = {
2548         .readpage       = btrfs_readpage,
2549         .writepage      = btrfs_writepage,
2550         .sync_page      = block_sync_page,
2551         .prepare_write  = btrfs_prepare_write,
2552         .commit_write   = btrfs_commit_write,
2553 };
2554
2555 static struct inode_operations btrfs_file_inode_operations = {
2556         .truncate       = btrfs_truncate,
2557         .getattr        = btrfs_getattr,
2558 };
2559
2560 static struct file_operations btrfs_file_operations = {
2561         .llseek         = generic_file_llseek,
2562         .read           = do_sync_read,
2563         .aio_read       = btrfs_file_aio_read,
2564         .write          = btrfs_file_write,
2565         .mmap           = generic_file_mmap,
2566         .open           = generic_file_open,
2567         .ioctl          = btrfs_ioctl,
2568         .fsync          = btrfs_sync_file,
2569 };
2570
2571 static int __init init_btrfs_fs(void)
2572 {
2573         int err;
2574         printk("btrfs loaded!\n");
2575         err = init_inodecache();
2576         if (err)
2577                 return err;
2578         return register_filesystem(&btrfs_fs_type);
2579         destroy_inodecache();
2580         return err;
2581 }
2582
2583 static void __exit exit_btrfs_fs(void)
2584 {
2585         destroy_inodecache();
2586         unregister_filesystem(&btrfs_fs_type);
2587         printk("btrfs unloaded\n");
2588 }
2589
2590 module_init(init_btrfs_fs)
2591 module_exit(exit_btrfs_fs)
2592
2593 MODULE_LICENSE("GPL");