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                 btrfs_extend_item(trans, root, path, data_size);
  53         } else if (ret < 0)
  54                 return ERR_PTR(ret);
  55         WARN_ON(ret > 0);
  56         leaf = path->nodes[0];
  57         item = btrfs_item_nr(leaf, path->slots[0]);
  58         ptr = btrfs_item_ptr(leaf, path->slots[0], char);
  59         BUG_ON(data_size > btrfs_item_size(leaf, item));
  60         ptr += btrfs_item_size(leaf, item) - data_size;
  61         return (struct btrfs_dir_item *)ptr;
  62 }
  63
  64 /*
  65  * xattrs work a lot like directories, this inserts an xattr item
  66  * into the tree
  67  */
  68 int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
  69                             struct btrfs_root *root,
  70                             struct btrfs_path *path, u64 objectid,
  71                             const char *name, u16 name_len,
  72                             const void *data, u16 data_len)
  73 {
  74         int ret = 0;
  75         struct btrfs_dir_item *dir_item;
  76         unsigned long name_ptr, data_ptr;
  77         struct btrfs_key key, location;
  78         struct btrfs_disk_key disk_key;
  79         struct extent_buffer *leaf;
  80         u32 data_size;
  81
  82         BUG_ON(name_len + data_len > BTRFS_MAX_XATTR_SIZE(root));
  83
  84         key.objectid = objectid;
  85         btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
  86         key.offset = btrfs_name_hash(name, name_len);
  87
  88         data_size = sizeof(*dir_item) + name_len + data_len;
  89         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
  90                                         name, name_len);
  91         if (IS_ERR(dir_item))
  92                 return PTR_ERR(dir_item);
  93         memset(&location, 0, sizeof(location));
  94
  95         leaf = path->nodes[0];
  96         btrfs_cpu_key_to_disk(&disk_key, &location);
  97         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
  98         btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
  99         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 100         btrfs_set_dir_transid(leaf, dir_item, trans->transid);
 101         btrfs_set_dir_data_len(leaf, dir_item, data_len);
 102         name_ptr = (unsigned long)(dir_item + 1);
 103         data_ptr = (unsigned long)((char *)name_ptr + name_len);
 104
 105         write_extent_buffer(leaf, name, name_ptr, name_len);
 106         write_extent_buffer(leaf, data, data_ptr, data_len);
 107         btrfs_mark_buffer_dirty(path->nodes[0]);
 108
 109         return ret;
 110 }
 111
 112 /*
 113  * insert a directory item in the tree, doing all the magic for
 114  * both indexes. 'dir' indicates which objectid to insert it into,
 115  * 'location' is the key to stuff into the directory item, 'type' is the
 116  * type of the inode we're pointing to, and 'index' is the sequence number
 117  * to use for the second index (if one is created).
 118  * Will return 0 or -ENOMEM
 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
 202         key.objectid = dir;
 203         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 204
 205         key.offset = btrfs_name_hash(name, name_len);
 206
 207         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 208         if (ret < 0)
 209                 return ERR_PTR(ret);
 210         if (ret > 0)
 211                 return NULL;
 212
 213         return btrfs_match_dir_item_name(root, path, name, name_len);
 214 }
 215
 216 /*
 217  * lookup a directory item based on index.  'dir' is the objectid
 218  * we're searching in, and 'mod' tells us if you plan on deleting the
 219  * item (use mod < 0) or changing the options (use mod > 0)
 220  *
 221  * The name is used to make sure the index really points to the name you were
 222  * looking for.
 223  */
 224 struct btrfs_dir_item *
 225 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 226                             struct btrfs_root *root,
 227                             struct btrfs_path *path, u64 dir,
 228                             u64 objectid, const char *name, int name_len,
 229                             int mod)
 230 {
 231         int ret;
 232         struct btrfs_key key;
 233         int ins_len = mod < 0 ? -1 : 0;
 234         int cow = mod != 0;
 235
 236         key.objectid = dir;
 237         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 238         key.offset = objectid;
 239
 240         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 241         if (ret < 0)
 242                 return ERR_PTR(ret);
 243         if (ret > 0)
 244                 return ERR_PTR(-ENOENT);
 245         return btrfs_match_dir_item_name(root, path, name, name_len);
 246 }
 247
 248 struct btrfs_dir_item *
 249 btrfs_search_dir_index_item(struct btrfs_root *root,
 250                             struct btrfs_path *path, u64 dirid,
 251                             const char *name, int name_len)
 252 {
 253         struct extent_buffer *leaf;
 254         struct btrfs_dir_item *di;
 255         struct btrfs_key key;
 256         u32 nritems;
 257         int ret;
 258
 259         key.objectid = dirid;
 260         key.type = BTRFS_DIR_INDEX_KEY;
 261         key.offset = 0;
 262
 263         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 264         if (ret < 0)
 265                 return ERR_PTR(ret);
 266
 267         leaf = path->nodes[0];
 268         nritems = btrfs_header_nritems(leaf);
 269
 270         while (1) {
 271                 if (path->slots[0] >= nritems) {
 272                         ret = btrfs_next_leaf(root, path);
 273                         if (ret < 0)
 274                                 return ERR_PTR(ret);
 275                         if (ret > 0)
 276                                 break;
 277                         leaf = path->nodes[0];
 278                         nritems = btrfs_header_nritems(leaf);
 279                         continue;
 280                 }
 281
 282                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 283                 if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
 284                         break;
 285
 286                 di = btrfs_match_dir_item_name(root, path, name, name_len);
 287                 if (di)
 288                         return di;
 289
 290                 path->slots[0]++;
 291         }
 292         return NULL;
 293 }
 294
 295 struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
 296                                           struct btrfs_root *root,
 297                                           struct btrfs_path *path, u64 dir,
 298                                           const char *name, u16 name_len,
 299                                           int mod)
 300 {
 301         int ret;
 302         struct btrfs_key key;
 303         int ins_len = mod < 0 ? -1 : 0;
 304         int cow = mod != 0;
 305
 306         key.objectid = dir;
 307         btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
 308         key.offset = btrfs_name_hash(name, name_len);
 309         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 310         if (ret < 0)
 311                 return ERR_PTR(ret);
 312         if (ret > 0)
 313                 return NULL;
 314
 315         return btrfs_match_dir_item_name(root, path, name, name_len);
 316 }
 317
 318 /*
 319  * helper function to look at the directory item pointed to by 'path'
 320  * this walks through all the entries in a dir item and finds one
 321  * for a specific name.
 322  */
 323 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 324                               struct btrfs_path *path,
 325                               const char *name, int name_len)
 326 {
 327         struct btrfs_dir_item *dir_item;
 328         unsigned long name_ptr;
 329         u32 total_len;
 330         u32 cur = 0;
 331         u32 this_len;
 332         struct extent_buffer *leaf;
 333
 334         leaf = path->nodes[0];
 335         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 336         if (verify_dir_item(root, leaf, dir_item))
 337                 return NULL;
 338
 339         total_len = btrfs_item_size_nr(leaf, path->slots[0]);
 340         while (cur < total_len) {
 341                 this_len = sizeof(*dir_item) +
 342                         btrfs_dir_name_len(leaf, dir_item) +
 343                         btrfs_dir_data_len(leaf, dir_item);
 344                 name_ptr = (unsigned long)(dir_item + 1);
 345
 346                 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
 347                     memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
 348                         return dir_item;
 349
 350                 cur += this_len;
 351                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 352                                                      this_len);
 353         }
 354         return NULL;
 355 }
 356
 357 /*
 358  * given a pointer into a directory item, delete it.  This
 359  * handles items that have more than one entry in them.
 360  */
 361 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 362                               struct btrfs_root *root,
 363                               struct btrfs_path *path,
 364                               struct btrfs_dir_item *di)
 365 {
 366
 367         struct extent_buffer *leaf;
 368         u32 sub_item_len;
 369         u32 item_len;
 370         int ret = 0;
 371
 372         leaf = path->nodes[0];
 373         sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
 374                 btrfs_dir_data_len(leaf, di);
 375         item_len = btrfs_item_size_nr(leaf, path->slots[0]);
 376         if (sub_item_len == item_len) {
 377                 ret = btrfs_del_item(trans, root, path);
 378         } else {
 379                 /* MARKER */
 380                 unsigned long ptr = (unsigned long)di;
 381                 unsigned long start;
 382
 383                 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 384                 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 385                         item_len - (ptr + sub_item_len - start));
 386                 btrfs_truncate_item(trans, root, path,
 387                                     item_len - sub_item_len, 1);
 388         }
 389         return ret;
 390 }
 391
 392 int verify_dir_item(struct btrfs_root *root,
 393                     struct extent_buffer *leaf,
 394                     struct btrfs_dir_item *dir_item)
 395 {
 396         u16 namelen = BTRFS_NAME_LEN;
 397         u8 type = btrfs_dir_type(leaf, dir_item);
 398
 399         if (type >= BTRFS_FT_MAX) {
 400                 printk(KERN_CRIT "btrfs: invalid dir item type: %d\n",
 401                        (int)type);
 402                 return 1;
 403         }
 404
 405         if (type == BTRFS_FT_XATTR)
 406                 namelen = XATTR_NAME_MAX;
 407
 408         if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
 409                 printk(KERN_CRIT "btrfs: invalid dir item name len: %u\n",
 410                        (unsigned)btrfs_dir_data_len(leaf, dir_item));
 411                 return 1;
 412         }
 413
 414         /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
 415         if (btrfs_dir_data_len(leaf, dir_item) > BTRFS_MAX_XATTR_SIZE(root)) {
 416                 printk(KERN_CRIT "btrfs: invalid dir item data len: %u\n",
 417                        (unsigned)btrfs_dir_data_len(leaf, dir_item));
 418                 return 1;
 419         }
 420
 421         return 0;
 422 }