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,
 127                           struct inode *dir, struct btrfs_key *location,
 128                           u8 type, u64 index)
 129 {
 130         int ret = 0;
 131         int ret2 = 0;
 132         struct btrfs_path *path;
 133         struct btrfs_dir_item *dir_item;
 134         struct extent_buffer *leaf;
 135         unsigned long name_ptr;
 136         struct btrfs_key key;
 137         struct btrfs_disk_key disk_key;
 138         u32 data_size;
 139
 140         key.objectid = btrfs_ino(dir);
 141         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 142         key.offset = btrfs_name_hash(name, name_len);
 143
 144         path = btrfs_alloc_path();
 145         if (!path)
 146                 return -ENOMEM;
 147         path->leave_spinning = 1;
 148
 149         btrfs_cpu_key_to_disk(&disk_key, location);
 150
 151         data_size = sizeof(*dir_item) + name_len;
 152         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 153                                         name, name_len);
 154         if (IS_ERR(dir_item)) {
 155                 ret = PTR_ERR(dir_item);
 156                 if (ret == -EEXIST)
 157                         goto second_insert;
 158                 goto out_free;
 159         }
 160
 161         leaf = path->nodes[0];
 162         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 163         btrfs_set_dir_type(leaf, dir_item, type);
 164         btrfs_set_dir_data_len(leaf, dir_item, 0);
 165         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 166         btrfs_set_dir_transid(leaf, dir_item, trans->transid);
 167         name_ptr = (unsigned long)(dir_item + 1);
 168
 169         write_extent_buffer(leaf, name, name_ptr, name_len);
 170         btrfs_mark_buffer_dirty(leaf);
 171
 172 second_insert:
 173         /* FIXME, use some real flag for selecting the extra index */
 174         if (root == root->fs_info->tree_root) {
 175                 ret = 0;
 176                 goto out_free;
 177         }
 178         btrfs_release_path(path);
 179
 180         ret2 = btrfs_insert_delayed_dir_index(trans, root, name, name_len, dir,
 181                                               &disk_key, type, index);
 182 out_free:
 183         btrfs_free_path(path);
 184         if (ret)
 185                 return ret;
 186         if (ret2)
 187                 return ret2;
 188         return 0;
 189 }
 190
 191 /*
 192  * lookup a directory item based on name.  'dir' is the objectid
 193  * we're searching in, and 'mod' tells us if you plan on deleting the
 194  * item (use mod < 0) or changing the options (use mod > 0)
 195  */
 196 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 197                                              struct btrfs_root *root,
 198                                              struct btrfs_path *path, u64 dir,
 199                                              const char *name, int name_len,
 200                                              int mod)
 201 {
 202         int ret;
 203         struct btrfs_key key;
 204         int ins_len = mod < 0 ? -1 : 0;
 205         int cow = mod != 0;
 206         struct btrfs_key found_key;
 207         struct extent_buffer *leaf;
 208
 209         key.objectid = dir;
 210         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 211
 212         key.offset = btrfs_name_hash(name, name_len);
 213
 214         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 215         if (ret < 0)
 216                 return ERR_PTR(ret);
 217         if (ret > 0) {
 218                 if (path->slots[0] == 0)
 219                         return NULL;
 220                 path->slots[0]--;
 221         }
 222
 223         leaf = path->nodes[0];
 224         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 225
 226         if (found_key.objectid != dir ||
 227             btrfs_key_type(&found_key) != BTRFS_DIR_ITEM_KEY ||
 228             found_key.offset != key.offset)
 229                 return NULL;
 230
 231         return btrfs_match_dir_item_name(root, path, name, name_len);
 232 }
 233
 234 /*
 235  * lookup a directory item based on index.  'dir' is the objectid
 236  * we're searching in, and 'mod' tells us if you plan on deleting the
 237  * item (use mod < 0) or changing the options (use mod > 0)
 238  *
 239  * The name is used to make sure the index really points to the name you were
 240  * looking for.
 241  */
 242 struct btrfs_dir_item *
 243 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 244                             struct btrfs_root *root,
 245                             struct btrfs_path *path, u64 dir,
 246                             u64 objectid, const char *name, int name_len,
 247                             int mod)
 248 {
 249         int ret;
 250         struct btrfs_key key;
 251         int ins_len = mod < 0 ? -1 : 0;
 252         int cow = mod != 0;
 253
 254         key.objectid = dir;
 255         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 256         key.offset = objectid;
 257
 258         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 259         if (ret < 0)
 260                 return ERR_PTR(ret);
 261         if (ret > 0)
 262                 return ERR_PTR(-ENOENT);
 263         return btrfs_match_dir_item_name(root, path, name, name_len);
 264 }
 265
 266 struct btrfs_dir_item *
 267 btrfs_search_dir_index_item(struct btrfs_root *root,
 268                             struct btrfs_path *path, u64 dirid,
 269                             const char *name, int name_len)
 270 {
 271         struct extent_buffer *leaf;
 272         struct btrfs_dir_item *di;
 273         struct btrfs_key key;
 274         u32 nritems;
 275         int ret;
 276
 277         key.objectid = dirid;
 278         key.type = BTRFS_DIR_INDEX_KEY;
 279         key.offset = 0;
 280
 281         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 282         if (ret < 0)
 283                 return ERR_PTR(ret);
 284
 285         leaf = path->nodes[0];
 286         nritems = btrfs_header_nritems(leaf);
 287
 288         while (1) {
 289                 if (path->slots[0] >= nritems) {
 290                         ret = btrfs_next_leaf(root, path);
 291                         if (ret < 0)
 292                                 return ERR_PTR(ret);
 293                         if (ret > 0)
 294                                 break;
 295                         leaf = path->nodes[0];
 296                         nritems = btrfs_header_nritems(leaf);
 297                         continue;
 298                 }
 299
 300                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 301                 if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
 302                         break;
 303
 304                 di = btrfs_match_dir_item_name(root, path, name, name_len);
 305                 if (di)
 306                         return di;
 307
 308                 path->slots[0]++;
 309         }
 310         return NULL;
 311 }
 312
 313 struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
 314                                           struct btrfs_root *root,
 315                                           struct btrfs_path *path, u64 dir,
 316                                           const char *name, u16 name_len,
 317                                           int mod)
 318 {
 319         int ret;
 320         struct btrfs_key key;
 321         int ins_len = mod < 0 ? -1 : 0;
 322         int cow = mod != 0;
 323         struct btrfs_key found_key;
 324         struct extent_buffer *leaf;
 325
 326         key.objectid = dir;
 327         btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
 328         key.offset = btrfs_name_hash(name, name_len);
 329         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 330         if (ret < 0)
 331                 return ERR_PTR(ret);
 332         if (ret > 0) {
 333                 if (path->slots[0] == 0)
 334                         return NULL;
 335                 path->slots[0]--;
 336         }
 337
 338         leaf = path->nodes[0];
 339         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 340
 341         if (found_key.objectid != dir ||
 342             btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY ||
 343             found_key.offset != key.offset)
 344                 return NULL;
 345
 346         return btrfs_match_dir_item_name(root, path, name, name_len);
 347 }
 348
 349 /*
 350  * helper function to look at the directory item pointed to by 'path'
 351  * this walks through all the entries in a dir item and finds one
 352  * for a specific name.
 353  */
 354 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 355                               struct btrfs_path *path,
 356                               const char *name, int name_len)
 357 {
 358         struct btrfs_dir_item *dir_item;
 359         unsigned long name_ptr;
 360         u32 total_len;
 361         u32 cur = 0;
 362         u32 this_len;
 363         struct extent_buffer *leaf;
 364
 365         leaf = path->nodes[0];
 366         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 367         if (verify_dir_item(root, leaf, dir_item))
 368                 return NULL;
 369
 370         total_len = btrfs_item_size_nr(leaf, path->slots[0]);
 371         while (cur < total_len) {
 372                 this_len = sizeof(*dir_item) +
 373                         btrfs_dir_name_len(leaf, dir_item) +
 374                         btrfs_dir_data_len(leaf, dir_item);
 375                 name_ptr = (unsigned long)(dir_item + 1);
 376
 377                 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
 378                     memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
 379                         return dir_item;
 380
 381                 cur += this_len;
 382                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 383                                                      this_len);
 384         }
 385         return NULL;
 386 }
 387
 388 /*
 389  * given a pointer into a directory item, delete it.  This
 390  * handles items that have more than one entry in them.
 391  */
 392 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 393                               struct btrfs_root *root,
 394                               struct btrfs_path *path,
 395                               struct btrfs_dir_item *di)
 396 {
 397
 398         struct extent_buffer *leaf;
 399         u32 sub_item_len;
 400         u32 item_len;
 401         int ret = 0;
 402
 403         leaf = path->nodes[0];
 404         sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
 405                 btrfs_dir_data_len(leaf, di);
 406         item_len = btrfs_item_size_nr(leaf, path->slots[0]);
 407         if (sub_item_len == item_len) {
 408                 ret = btrfs_del_item(trans, root, path);
 409         } else {
 410                 /* MARKER */
 411                 unsigned long ptr = (unsigned long)di;
 412                 unsigned long start;
 413
 414                 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 415                 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 416                         item_len - (ptr + sub_item_len - start));
 417                 ret = btrfs_truncate_item(trans, root, path,
 418                                           item_len - sub_item_len, 1);
 419         }
 420         return ret;
 421 }
 422
 423 int verify_dir_item(struct btrfs_root *root,
 424                     struct extent_buffer *leaf,
 425                     struct btrfs_dir_item *dir_item)
 426 {
 427         u16 namelen = BTRFS_NAME_LEN;
 428         u8 type = btrfs_dir_type(leaf, dir_item);
 429
 430         if (type >= BTRFS_FT_MAX) {
 431                 printk(KERN_CRIT "btrfs: invalid dir item type: %d\n",
 432                        (int)type);
 433                 return 1;
 434         }
 435
 436         if (type == BTRFS_FT_XATTR)
 437                 namelen = XATTR_NAME_MAX;
 438
 439         if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
 440                 printk(KERN_CRIT "btrfs: invalid dir item name len: %u\n",
 441                        (unsigned)btrfs_dir_data_len(leaf, dir_item));
 442                 return 1;
 443         }
 444
 445         /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
 446         if (btrfs_dir_data_len(leaf, dir_item) > BTRFS_MAX_XATTR_SIZE(root)) {
 447                 printk(KERN_CRIT "btrfs: invalid dir item data len: %u\n",
 448                        (unsigned)btrfs_dir_data_len(leaf, dir_item));
 449                 return 1;
 450         }
 451
 452         return 0;
 453 }