fs/btrfs/dir-item.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include "ctree.h"
  20 #include "disk-io.h"
  21 #include "hash.h"
  22 #include "transaction.h"
  23
  24 /*
  25  * insert a name into a directory, doing overflow properly if there is a hash
  26  * collision.  data_size indicates how big the item inserted should be.  On
  27  * success a struct btrfs_dir_item pointer is returned, otherwise it is
  28  * an ERR_PTR.
  29  *
  30  * The name is not copied into the dir item, you have to do that yourself.
  31  */
  32 static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
  33                                                    *trans,
  34                                                    struct btrfs_root *root,
  35                                                    struct btrfs_path *path,
  36                                                    struct btrfs_key *cpu_key,
  37                                                    u32 data_size,
  38                                                    const char *name,
  39                                                    int name_len)
  40 {
  41         int ret;
  42         char *ptr;
  43         struct btrfs_item *item;
  44         struct extent_buffer *leaf;
  45
  46         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
  47         if (ret == -EEXIST) {
  48                 struct btrfs_dir_item *di;
  49                 di = btrfs_match_dir_item_name(root, path, name, name_len);
  50                 if (di)
  51                         return ERR_PTR(-EEXIST);
  52                 ret = btrfs_extend_item(trans, root, path, data_size);
  53         }
  54         if (ret < 0)
  55                 return ERR_PTR(ret);
  56         WARN_ON(ret > 0);
  57         leaf = path->nodes[0];
  58         item = btrfs_item_nr(leaf, path->slots[0]);
  59         ptr = btrfs_item_ptr(leaf, path->slots[0], char);
  60         BUG_ON(data_size > btrfs_item_size(leaf, item));
  61         ptr += btrfs_item_size(leaf, item) - data_size;
  62         return (struct btrfs_dir_item *)ptr;
  63 }
  64
  65 /*
  66  * xattrs work a lot like directories, this inserts an xattr item
  67  * into the tree
  68  */
  69 int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
  70                             struct btrfs_root *root,
  71                             struct btrfs_path *path, u64 objectid,
  72                             const char *name, u16 name_len,
  73                             const void *data, u16 data_len)
  74 {
  75         int ret = 0;
  76         struct btrfs_dir_item *dir_item;
  77         unsigned long name_ptr, data_ptr;
  78         struct btrfs_key key, location;
  79         struct btrfs_disk_key disk_key;
  80         struct extent_buffer *leaf;
  81         u32 data_size;
  82
  83         BUG_ON(name_len + data_len > BTRFS_MAX_XATTR_SIZE(root));
  84
  85         key.objectid = objectid;
  86         btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
  87         key.offset = btrfs_name_hash(name, name_len);
  88
  89         data_size = sizeof(*dir_item) + name_len + data_len;
  90         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
  91                                         name, name_len);
  92         /*
  93          * FIXME: at some point we should handle xattr's that are larger than
  94          * what we can fit in our leaf.  We set location to NULL b/c we arent
  95          * pointing at anything else, that will change if we store the xattr
  96          * data in a separate inode.
  97          */
  98         BUG_ON(IS_ERR(dir_item));
  99         memset(&location, 0, sizeof(location));
 100
 101         leaf = path->nodes[0];
 102         btrfs_cpu_key_to_disk(&disk_key, &location);
 103         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 104         btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
 105         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 106         btrfs_set_dir_transid(leaf, dir_item, trans->transid);
 107         btrfs_set_dir_data_len(leaf, dir_item, data_len);
 108         name_ptr = (unsigned long)(dir_item + 1);
 109         data_ptr = (unsigned long)((char *)name_ptr + name_len);
 110
 111         write_extent_buffer(leaf, name, name_ptr, name_len);
 112         write_extent_buffer(leaf, data, data_ptr, data_len);
 113         btrfs_mark_buffer_dirty(path->nodes[0]);
 114
 115         return ret;
 116 }
 117
 118 /*
 119  * insert a directory item in the tree, doing all the magic for
 120  * both indexes. 'dir' indicates which objectid to insert it into,
 121  * 'location' is the key to stuff into the directory item, 'type' is the
 122  * type of the inode we're pointing to, and 'index' is the sequence number
 123  * to use for the second index (if one is created).
 124  */
 125 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 126                           *root, const char *name, int name_len, u64 dir,
 127                           struct btrfs_key *location, u8 type, u64 index)
 128 {
 129         int ret = 0;
 130         int ret2 = 0;
 131         struct btrfs_path *path;
 132         struct btrfs_dir_item *dir_item;
 133         struct extent_buffer *leaf;
 134         unsigned long name_ptr;
 135         struct btrfs_key key;
 136         struct btrfs_disk_key disk_key;
 137         u32 data_size;
 138
 139         key.objectid = dir;
 140         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 141         key.offset = btrfs_name_hash(name, name_len);
 142
 143         path = btrfs_alloc_path();
 144         path->leave_spinning = 1;
 145
 146         data_size = sizeof(*dir_item) + name_len;
 147         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 148                                         name, name_len);
 149         if (IS_ERR(dir_item)) {
 150                 ret = PTR_ERR(dir_item);
 151                 if (ret == -EEXIST)
 152                         goto second_insert;
 153                 goto out_free;
 154         }
 155
 156         leaf = path->nodes[0];
 157         btrfs_cpu_key_to_disk(&disk_key, location);
 158         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 159         btrfs_set_dir_type(leaf, dir_item, type);
 160         btrfs_set_dir_data_len(leaf, dir_item, 0);
 161         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 162         btrfs_set_dir_transid(leaf, dir_item, trans->transid);
 163         name_ptr = (unsigned long)(dir_item + 1);
 164
 165         write_extent_buffer(leaf, name, name_ptr, name_len);
 166         btrfs_mark_buffer_dirty(leaf);
 167
 168 second_insert:
 169         /* FIXME, use some real flag for selecting the extra index */
 170         if (root == root->fs_info->tree_root) {
 171                 ret = 0;
 172                 goto out_free;
 173         }
 174         btrfs_release_path(root, path);
 175
 176         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 177         key.offset = index;
 178         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 179                                         name, name_len);
 180         if (IS_ERR(dir_item)) {
 181                 ret2 = PTR_ERR(dir_item);
 182                 goto out_free;
 183         }
 184         leaf = path->nodes[0];
 185         btrfs_cpu_key_to_disk(&disk_key, location);
 186         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 187         btrfs_set_dir_type(leaf, dir_item, type);
 188         btrfs_set_dir_data_len(leaf, dir_item, 0);
 189         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 190         btrfs_set_dir_transid(leaf, dir_item, trans->transid);
 191         name_ptr = (unsigned long)(dir_item + 1);
 192         write_extent_buffer(leaf, name, name_ptr, name_len);
 193         btrfs_mark_buffer_dirty(leaf);
 194
 195 out_free:
 196
 197         btrfs_free_path(path);
 198         if (ret)
 199                 return ret;
 200         if (ret2)
 201                 return ret2;
 202         return 0;
 203 }
 204
 205 /*
 206  * lookup a directory item based on name.  'dir' is the objectid
 207  * we're searching in, and 'mod' tells us if you plan on deleting the
 208  * item (use mod < 0) or changing the options (use mod > 0)
 209  */
 210 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 211                                              struct btrfs_root *root,
 212                                              struct btrfs_path *path, u64 dir,
 213                                              const char *name, int name_len,
 214                                              int mod)
 215 {
 216         int ret;
 217         struct btrfs_key key;
 218         int ins_len = mod < 0 ? -1 : 0;
 219         int cow = mod != 0;
 220         struct btrfs_key found_key;
 221         struct extent_buffer *leaf;
 222
 223         key.objectid = dir;
 224         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 225
 226         key.offset = btrfs_name_hash(name, name_len);
 227
 228         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 229         if (ret < 0)
 230                 return ERR_PTR(ret);
 231         if (ret > 0) {
 232                 if (path->slots[0] == 0)
 233                         return NULL;
 234                 path->slots[0]--;
 235         }
 236
 237         leaf = path->nodes[0];
 238         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 239
 240         if (found_key.objectid != dir ||
 241             btrfs_key_type(&found_key) != BTRFS_DIR_ITEM_KEY ||
 242             found_key.offset != key.offset)
 243                 return NULL;
 244
 245         return btrfs_match_dir_item_name(root, path, name, name_len);
 246 }
 247
 248 /*
 249  * lookup a directory item based on index.  'dir' is the objectid
 250  * we're searching in, and 'mod' tells us if you plan on deleting the
 251  * item (use mod < 0) or changing the options (use mod > 0)
 252  *
 253  * The name is used to make sure the index really points to the name you were
 254  * looking for.
 255  */
 256 struct btrfs_dir_item *
 257 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 258                             struct btrfs_root *root,
 259                             struct btrfs_path *path, u64 dir,
 260                             u64 objectid, const char *name, int name_len,
 261                             int mod)
 262 {
 263         int ret;
 264         struct btrfs_key key;
 265         int ins_len = mod < 0 ? -1 : 0;
 266         int cow = mod != 0;
 267
 268         key.objectid = dir;
 269         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 270         key.offset = objectid;
 271
 272         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 273         if (ret < 0)
 274                 return ERR_PTR(ret);
 275         if (ret > 0)
 276                 return ERR_PTR(-ENOENT);
 277         return btrfs_match_dir_item_name(root, path, name, name_len);
 278 }
 279
 280 struct btrfs_dir_item *
 281 btrfs_search_dir_index_item(struct btrfs_root *root,
 282                             struct btrfs_path *path, u64 dirid,
 283                             const char *name, int name_len)
 284 {
 285         struct extent_buffer *leaf;
 286         struct btrfs_dir_item *di;
 287         struct btrfs_key key;
 288         u32 nritems;
 289         int ret;
 290
 291         key.objectid = dirid;
 292         key.type = BTRFS_DIR_INDEX_KEY;
 293         key.offset = 0;
 294
 295         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 296         if (ret < 0)
 297                 return ERR_PTR(ret);
 298
 299         leaf = path->nodes[0];
 300         nritems = btrfs_header_nritems(leaf);
 301
 302         while (1) {
 303                 if (path->slots[0] >= nritems) {
 304                         ret = btrfs_next_leaf(root, path);
 305                         if (ret < 0)
 306                                 return ERR_PTR(ret);
 307                         if (ret > 0)
 308                                 break;
 309                         leaf = path->nodes[0];
 310                         nritems = btrfs_header_nritems(leaf);
 311                         continue;
 312                 }
 313
 314                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 315                 if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
 316                         break;
 317
 318                 di = btrfs_match_dir_item_name(root, path, name, name_len);
 319                 if (di)
 320                         return di;
 321
 322                 path->slots[0]++;
 323         }
 324         return NULL;
 325 }
 326
 327 struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
 328                                           struct btrfs_root *root,
 329                                           struct btrfs_path *path, u64 dir,
 330                                           const char *name, u16 name_len,
 331                                           int mod)
 332 {
 333         int ret;
 334         struct btrfs_key key;
 335         int ins_len = mod < 0 ? -1 : 0;
 336         int cow = mod != 0;
 337         struct btrfs_key found_key;
 338         struct extent_buffer *leaf;
 339
 340         key.objectid = dir;
 341         btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
 342         key.offset = btrfs_name_hash(name, name_len);
 343         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 344         if (ret < 0)
 345                 return ERR_PTR(ret);
 346         if (ret > 0) {
 347                 if (path->slots[0] == 0)
 348                         return NULL;
 349                 path->slots[0]--;
 350         }
 351
 352         leaf = path->nodes[0];
 353         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 354
 355         if (found_key.objectid != dir ||
 356             btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY ||
 357             found_key.offset != key.offset)
 358                 return NULL;
 359
 360         return btrfs_match_dir_item_name(root, path, name, name_len);
 361 }
 362
 363 /*
 364  * helper function to look at the directory item pointed to by 'path'
 365  * this walks through all the entries in a dir item and finds one
 366  * for a specific name.
 367  */
 368 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 369                               struct btrfs_path *path,
 370                               const char *name, int name_len)
 371 {
 372         struct btrfs_dir_item *dir_item;
 373         unsigned long name_ptr;
 374         u32 total_len;
 375         u32 cur = 0;
 376         u32 this_len;
 377         struct extent_buffer *leaf;
 378
 379         leaf = path->nodes[0];
 380         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 381         if (verify_dir_item(root, leaf, dir_item))
 382                 return NULL;
 383
 384         total_len = btrfs_item_size_nr(leaf, path->slots[0]);
 385         while (cur < total_len) {
 386                 this_len = sizeof(*dir_item) +
 387                         btrfs_dir_name_len(leaf, dir_item) +
 388                         btrfs_dir_data_len(leaf, dir_item);
 389                 name_ptr = (unsigned long)(dir_item + 1);
 390
 391                 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
 392                     memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
 393                         return dir_item;
 394
 395                 cur += this_len;
 396                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 397                                                      this_len);
 398         }
 399         return NULL;
 400 }
 401
 402 /*
 403  * given a pointer into a directory item, delete it.  This
 404  * handles items that have more than one entry in them.
 405  */
 406 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 407                               struct btrfs_root *root,
 408                               struct btrfs_path *path,
 409                               struct btrfs_dir_item *di)
 410 {
 411
 412         struct extent_buffer *leaf;
 413         u32 sub_item_len;
 414         u32 item_len;
 415         int ret = 0;
 416
 417         leaf = path->nodes[0];
 418         sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
 419                 btrfs_dir_data_len(leaf, di);
 420         item_len = btrfs_item_size_nr(leaf, path->slots[0]);
 421         if (sub_item_len == item_len) {
 422                 ret = btrfs_del_item(trans, root, path);
 423         } else {
 424                 /* MARKER */
 425                 unsigned long ptr = (unsigned long)di;
 426                 unsigned long start;
 427
 428                 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 429                 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 430                         item_len - (ptr + sub_item_len - start));
 431                 ret = btrfs_truncate_item(trans, root, path,
 432                                           item_len - sub_item_len, 1);
 433         }
 434         return ret;
 435 }
 436
 437 int verify_dir_item(struct btrfs_root *root,
 438                     struct extent_buffer *leaf,
 439                     struct btrfs_dir_item *dir_item)
 440 {
 441         u16 namelen = BTRFS_NAME_LEN;
 442         u8 type = btrfs_dir_type(leaf, dir_item);
 443
 444         if (type >= BTRFS_FT_MAX) {
 445                 printk(KERN_CRIT "btrfs: invalid dir item type: %d\n",
 446                        (int)type);
 447                 return 1;
 448         }
 449
 450         if (type == BTRFS_FT_XATTR)
 451                 namelen = XATTR_NAME_MAX;
 452
 453         if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
 454                 printk(KERN_CRIT "btrfs: invalid dir item name len: %u\n",
 455                        (unsigned)btrfs_dir_data_len(leaf, dir_item));
 456                 return 1;
 457         }
 458
 459         /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
 460         if (btrfs_dir_data_len(leaf, dir_item) > BTRFS_MAX_XATTR_SIZE(root)) {
 461                 printk(KERN_CRIT "btrfs: invalid dir item data len: %u\n",
 462                        (unsigned)btrfs_dir_data_len(leaf, dir_item));
 463                 return 1;
 464         }
 465
 466         return 0;
 467 }