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         if (IS_ERR(dir_item))
  93                 return PTR_ERR(dir_item);
  94         memset(&location, 0, sizeof(location));
  95
  96         leaf = path->nodes[0];
  97         btrfs_cpu_key_to_disk(&disk_key, &location);
  98         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
  99         btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
 100         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 101         btrfs_set_dir_transid(leaf, dir_item, trans->transid);
 102         btrfs_set_dir_data_len(leaf, dir_item, data_len);
 103         name_ptr = (unsigned long)(dir_item + 1);
 104         data_ptr = (unsigned long)((char *)name_ptr + name_len);
 105
 106         write_extent_buffer(leaf, name, name_ptr, name_len);
 107         write_extent_buffer(leaf, data, data_ptr, data_len);
 108         btrfs_mark_buffer_dirty(path->nodes[0]);
 109
 110         return ret;
 111 }
 112
 113 /*
 114  * insert a directory item in the tree, doing all the magic for
 115  * both indexes. 'dir' indicates which objectid to insert it into,
 116  * 'location' is the key to stuff into the directory item, 'type' is the
 117  * type of the inode we're pointing to, and 'index' is the sequence number
 118  * to use for the second index (if one is created).
 119  */
 120 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 121                           *root, const char *name, int name_len,
 122                           struct inode *dir, struct btrfs_key *location,
 123                           u8 type, u64 index)
 124 {
 125         int ret = 0;
 126         int ret2 = 0;
 127         struct btrfs_path *path;
 128         struct btrfs_dir_item *dir_item;
 129         struct extent_buffer *leaf;
 130         unsigned long name_ptr;
 131         struct btrfs_key key;
 132         struct btrfs_disk_key disk_key;
 133         u32 data_size;
 134
 135         key.objectid = btrfs_ino(dir);
 136         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 137         key.offset = btrfs_name_hash(name, name_len);
 138
 139         path = btrfs_alloc_path();
 140         if (!path)
 141                 return -ENOMEM;
 142         path->leave_spinning = 1;
 143
 144         btrfs_cpu_key_to_disk(&disk_key, location);
 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_set_dir_item_key(leaf, dir_item, &disk_key);
 158         btrfs_set_dir_type(leaf, dir_item, type);
 159         btrfs_set_dir_data_len(leaf, dir_item, 0);
 160         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 161         btrfs_set_dir_transid(leaf, dir_item, trans->transid);
 162         name_ptr = (unsigned long)(dir_item + 1);
 163
 164         write_extent_buffer(leaf, name, name_ptr, name_len);
 165         btrfs_mark_buffer_dirty(leaf);
 166
 167 second_insert:
 168         /* FIXME, use some real flag for selecting the extra index */
 169         if (root == root->fs_info->tree_root) {
 170                 ret = 0;
 171                 goto out_free;
 172         }
 173         btrfs_release_path(path);
 174
 175         ret2 = btrfs_insert_delayed_dir_index(trans, root, name, name_len, dir,
 176                                               &disk_key, type, index);
 177 out_free:
 178         btrfs_free_path(path);
 179         if (ret)
 180                 return ret;
 181         if (ret2)
 182                 return ret2;
 183         return 0;
 184 }
 185
 186 /*
 187  * lookup a directory item based on name.  'dir' is the objectid
 188  * we're searching in, and 'mod' tells us if you plan on deleting the
 189  * item (use mod < 0) or changing the options (use mod > 0)
 190  */
 191 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 192                                              struct btrfs_root *root,
 193                                              struct btrfs_path *path, u64 dir,
 194                                              const char *name, int name_len,
 195                                              int mod)
 196 {
 197         int ret;
 198         struct btrfs_key key;
 199         int ins_len = mod < 0 ? -1 : 0;
 200         int cow = mod != 0;
 201         struct btrfs_key found_key;
 202         struct extent_buffer *leaf;
 203
 204         key.objectid = dir;
 205         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 206
 207         key.offset = btrfs_name_hash(name, name_len);
 208
 209         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 210         if (ret < 0)
 211                 return ERR_PTR(ret);
 212         if (ret > 0) {
 213                 if (path->slots[0] == 0)
 214                         return NULL;
 215                 path->slots[0]--;
 216         }
 217
 218         leaf = path->nodes[0];
 219         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 220
 221         if (found_key.objectid != dir ||
 222             btrfs_key_type(&found_key) != BTRFS_DIR_ITEM_KEY ||
 223             found_key.offset != key.offset)
 224                 return NULL;
 225
 226         return btrfs_match_dir_item_name(root, path, name, name_len);
 227 }
 228
 229 /*
 230  * lookup a directory item based on index.  'dir' is the objectid
 231  * we're searching in, and 'mod' tells us if you plan on deleting the
 232  * item (use mod < 0) or changing the options (use mod > 0)
 233  *
 234  * The name is used to make sure the index really points to the name you were
 235  * looking for.
 236  */
 237 struct btrfs_dir_item *
 238 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 239                             struct btrfs_root *root,
 240                             struct btrfs_path *path, u64 dir,
 241                             u64 objectid, const char *name, int name_len,
 242                             int mod)
 243 {
 244         int ret;
 245         struct btrfs_key key;
 246         int ins_len = mod < 0 ? -1 : 0;
 247         int cow = mod != 0;
 248
 249         key.objectid = dir;
 250         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 251         key.offset = objectid;
 252
 253         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 254         if (ret < 0)
 255                 return ERR_PTR(ret);
 256         if (ret > 0)
 257                 return ERR_PTR(-ENOENT);
 258         return btrfs_match_dir_item_name(root, path, name, name_len);
 259 }
 260
 261 struct btrfs_dir_item *
 262 btrfs_search_dir_index_item(struct btrfs_root *root,
 263                             struct btrfs_path *path, u64 dirid,
 264                             const char *name, int name_len)
 265 {
 266         struct extent_buffer *leaf;
 267         struct btrfs_dir_item *di;
 268         struct btrfs_key key;
 269         u32 nritems;
 270         int ret;
 271
 272         key.objectid = dirid;
 273         key.type = BTRFS_DIR_INDEX_KEY;
 274         key.offset = 0;
 275
 276         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 277         if (ret < 0)
 278                 return ERR_PTR(ret);
 279
 280         leaf = path->nodes[0];
 281         nritems = btrfs_header_nritems(leaf);
 282
 283         while (1) {
 284                 if (path->slots[0] >= nritems) {
 285                         ret = btrfs_next_leaf(root, path);
 286                         if (ret < 0)
 287                                 return ERR_PTR(ret);
 288                         if (ret > 0)
 289                                 break;
 290                         leaf = path->nodes[0];
 291                         nritems = btrfs_header_nritems(leaf);
 292                         continue;
 293                 }
 294
 295                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 296                 if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
 297                         break;
 298
 299                 di = btrfs_match_dir_item_name(root, path, name, name_len);
 300                 if (di)
 301                         return di;
 302
 303                 path->slots[0]++;
 304         }
 305         return NULL;
 306 }
 307
 308 struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
 309                                           struct btrfs_root *root,
 310                                           struct btrfs_path *path, u64 dir,
 311                                           const char *name, u16 name_len,
 312                                           int mod)
 313 {
 314         int ret;
 315         struct btrfs_key key;
 316         int ins_len = mod < 0 ? -1 : 0;
 317         int cow = mod != 0;
 318         struct btrfs_key found_key;
 319         struct extent_buffer *leaf;
 320
 321         key.objectid = dir;
 322         btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
 323         key.offset = btrfs_name_hash(name, name_len);
 324         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 325         if (ret < 0)
 326                 return ERR_PTR(ret);
 327         if (ret > 0) {
 328                 if (path->slots[0] == 0)
 329                         return NULL;
 330                 path->slots[0]--;
 331         }
 332
 333         leaf = path->nodes[0];
 334         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 335
 336         if (found_key.objectid != dir ||
 337             btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY ||
 338             found_key.offset != key.offset)
 339                 return NULL;
 340
 341         return btrfs_match_dir_item_name(root, path, name, name_len);
 342 }
 343
 344 /*
 345  * helper function to look at the directory item pointed to by 'path'
 346  * this walks through all the entries in a dir item and finds one
 347  * for a specific name.
 348  */
 349 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 350                               struct btrfs_path *path,
 351                               const char *name, int name_len)
 352 {
 353         struct btrfs_dir_item *dir_item;
 354         unsigned long name_ptr;
 355         u32 total_len;
 356         u32 cur = 0;
 357         u32 this_len;
 358         struct extent_buffer *leaf;
 359
 360         leaf = path->nodes[0];
 361         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 362         if (verify_dir_item(root, leaf, dir_item))
 363                 return NULL;
 364
 365         total_len = btrfs_item_size_nr(leaf, path->slots[0]);
 366         while (cur < total_len) {
 367                 this_len = sizeof(*dir_item) +
 368                         btrfs_dir_name_len(leaf, dir_item) +
 369                         btrfs_dir_data_len(leaf, dir_item);
 370                 name_ptr = (unsigned long)(dir_item + 1);
 371
 372                 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
 373                     memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
 374                         return dir_item;
 375
 376                 cur += this_len;
 377                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 378                                                      this_len);
 379         }
 380         return NULL;
 381 }
 382
 383 /*
 384  * given a pointer into a directory item, delete it.  This
 385  * handles items that have more than one entry in them.
 386  */
 387 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 388                               struct btrfs_root *root,
 389                               struct btrfs_path *path,
 390                               struct btrfs_dir_item *di)
 391 {
 392
 393         struct extent_buffer *leaf;
 394         u32 sub_item_len;
 395         u32 item_len;
 396         int ret = 0;
 397
 398         leaf = path->nodes[0];
 399         sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
 400                 btrfs_dir_data_len(leaf, di);
 401         item_len = btrfs_item_size_nr(leaf, path->slots[0]);
 402         if (sub_item_len == item_len) {
 403                 ret = btrfs_del_item(trans, root, path);
 404         } else {
 405                 /* MARKER */
 406                 unsigned long ptr = (unsigned long)di;
 407                 unsigned long start;
 408
 409                 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 410                 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 411                         item_len - (ptr + sub_item_len - start));
 412                 ret = btrfs_truncate_item(trans, root, path,
 413                                           item_len - sub_item_len, 1);
 414         }
 415         return ret;
 416 }
 417
 418 int verify_dir_item(struct btrfs_root *root,
 419                     struct extent_buffer *leaf,
 420                     struct btrfs_dir_item *dir_item)
 421 {
 422         u16 namelen = BTRFS_NAME_LEN;
 423         u8 type = btrfs_dir_type(leaf, dir_item);
 424
 425         if (type >= BTRFS_FT_MAX) {
 426                 printk(KERN_CRIT "btrfs: invalid dir item type: %d\n",
 427                        (int)type);
 428                 return 1;
 429         }
 430
 431         if (type == BTRFS_FT_XATTR)
 432                 namelen = XATTR_NAME_MAX;
 433
 434         if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
 435                 printk(KERN_CRIT "btrfs: invalid dir item name len: %u\n",
 436                        (unsigned)btrfs_dir_data_len(leaf, dir_item));
 437                 return 1;
 438         }
 439
 440         /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
 441         if (btrfs_dir_data_len(leaf, dir_item) > BTRFS_MAX_XATTR_SIZE(root)) {
 442                 printk(KERN_CRIT "btrfs: invalid dir item data len: %u\n",
 443                        (unsigned)btrfs_dir_data_len(leaf, dir_item));
 444                 return 1;
 445         }
 446
 447         return 0;
 448 }