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 <linux/limits.h>
  20 #include "ctree.h"
  21 #include "disk-io.h"
  22 #include "hash.h"
  23 #include "transaction.h"
  24
  25 static struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
  26                               struct btrfs_path *path,
  27                               const char *name, int name_len);
  28
  29 static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
  30                                                    *trans,
  31                                                    struct btrfs_root *root,
  32                                                    struct btrfs_path *path,
  33                                                    struct btrfs_key *cpu_key,
  34                                                    u32 data_size,
  35                                                    const char *name,
  36                                                    int name_len)
  37 {
  38         int ret;
  39         char *ptr;
  40         struct btrfs_item *item;
  41         struct extent_buffer *leaf;
  42
  43         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
  44         if (ret == -EEXIST) {
  45                 struct btrfs_dir_item *di;
  46                 di = btrfs_match_dir_item_name(root, path, name, name_len);
  47                 if (di)
  48                         return ERR_PTR(-EEXIST);
  49                 ret = btrfs_extend_item(root, path, data_size);
  50                 WARN_ON(ret > 0);
  51         }
  52         if (ret < 0)
  53                 return ERR_PTR(ret);
  54         WARN_ON(ret > 0);
  55         leaf = path->nodes[0];
  56         item = btrfs_item_nr(path->slots[0]);
  57         ptr = btrfs_item_ptr(leaf, path->slots[0], char);
  58         BUG_ON(data_size > btrfs_item_size(leaf, item));
  59         ptr += btrfs_item_size(leaf, item) - data_size;
  60         return (struct btrfs_dir_item *)ptr;
  61 }
  62
  63 int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
  64                             struct btrfs_root *root, const char *name,
  65                             u16 name_len, const void *data, u16 data_len,
  66                             u64 dir)
  67 {
  68         int ret = 0;
  69         struct btrfs_path *path;
  70         struct btrfs_dir_item *dir_item;
  71         unsigned long name_ptr, data_ptr;
  72         struct btrfs_key key, location;
  73         struct btrfs_disk_key disk_key;
  74         struct extent_buffer *leaf;
  75         u32 data_size;
  76
  77         key.objectid = dir;
  78         key.type = BTRFS_XATTR_ITEM_KEY;
  79         key.offset = btrfs_name_hash(name, name_len);
  80         path = btrfs_alloc_path();
  81         if (!path)
  82                 return -ENOMEM;
  83
  84         data_size = sizeof(*dir_item) + name_len + data_len;
  85         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
  86                                         name, name_len);
  87         /*
  88          * FIXME: at some point we should handle xattr's that are larger than
  89          * what we can fit in our leaf.  We set location to NULL b/c we aren't
  90          * pointing at anything else, that will change if we store the xattr
  91          * data in a separate inode.
  92          */
  93         BUG_ON(IS_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_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         btrfs_free_path(path);
 110         return ret;
 111 }
 112
 113 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 114                           *root, const char *name, int name_len, u64 dir,
 115                           struct btrfs_key *location, u8 type, u64 index)
 116 {
 117         int ret = 0;
 118         int ret2 = 0;
 119         struct btrfs_path *path;
 120         struct btrfs_dir_item *dir_item;
 121         struct extent_buffer *leaf;
 122         unsigned long name_ptr;
 123         struct btrfs_key key;
 124         struct btrfs_disk_key disk_key;
 125         u32 data_size;
 126
 127         key.objectid = dir;
 128         key.type = BTRFS_DIR_ITEM_KEY;
 129         key.offset = btrfs_name_hash(name, name_len);
 130         path = btrfs_alloc_path();
 131         if (!path)
 132                 return -ENOMEM;
 133         data_size = sizeof(*dir_item) + name_len;
 134         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 135                                         name, name_len);
 136         if (IS_ERR(dir_item)) {
 137                 ret = PTR_ERR(dir_item);
 138
 139                 /* Continue to insert item if existed */
 140                 if (ret == -EEXIST) {
 141                         ret = 0;
 142                         goto insert;
 143                 } else {
 144                         goto out;
 145                 }
 146         }
 147
 148         leaf = path->nodes[0];
 149         btrfs_cpu_key_to_disk(&disk_key, location);
 150         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 151         btrfs_set_dir_type(leaf, dir_item, type);
 152         btrfs_set_dir_data_len(leaf, dir_item, 0);
 153         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 154         name_ptr = (unsigned long)(dir_item + 1);
 155
 156         write_extent_buffer(leaf, name, name_ptr, name_len);
 157         btrfs_mark_buffer_dirty(leaf);
 158
 159 insert:
 160         /* FIXME, use some real flag for selecting the extra index */
 161         if (root == root->fs_info->tree_root) {
 162                 ret = 0;
 163                 goto out;
 164         }
 165         btrfs_release_path(path);
 166
 167         key.type = BTRFS_DIR_INDEX_KEY;
 168         key.offset = index;
 169         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 170                                         name, name_len);
 171         if (IS_ERR(dir_item)) {
 172                 ret2 = PTR_ERR(dir_item);
 173                 if (ret2 == -EEXIST)
 174                         ret = 0;
 175                 goto out;
 176         }
 177         leaf = path->nodes[0];
 178         btrfs_cpu_key_to_disk(&disk_key, location);
 179         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 180         btrfs_set_dir_type(leaf, dir_item, type);
 181         btrfs_set_dir_data_len(leaf, dir_item, 0);
 182         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 183         name_ptr = (unsigned long)(dir_item + 1);
 184         write_extent_buffer(leaf, name, name_ptr, name_len);
 185         btrfs_mark_buffer_dirty(leaf);
 186 out:
 187         btrfs_free_path(path);
 188         if (ret)
 189                 return ret;
 190         if (ret2)
 191                 return ret2;
 192         return 0;
 193 }
 194
 195 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 196                                              struct btrfs_root *root,
 197                                              struct btrfs_path *path, u64 dir,
 198                                              const char *name, int name_len,
 199                                              int mod)
 200 {
 201         int ret;
 202         struct btrfs_key key;
 203         int ins_len = mod < 0 ? -1 : 0;
 204         int cow = mod != 0;
 205         struct btrfs_key found_key;
 206         struct extent_buffer *leaf;
 207
 208         key.objectid = dir;
 209         key.type = BTRFS_DIR_ITEM_KEY;
 210
 211         key.offset = btrfs_name_hash(name, name_len);
 212
 213         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 214         if (ret < 0)
 215                 return ERR_PTR(ret);
 216         if (ret > 0) {
 217                 if (path->slots[0] == 0)
 218                         return NULL;
 219                 path->slots[0]--;
 220         }
 221
 222         leaf = path->nodes[0];
 223         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 224
 225         if (found_key.objectid != dir ||
 226             found_key.type != BTRFS_DIR_ITEM_KEY ||
 227             found_key.offset != key.offset)
 228                 return NULL;
 229
 230         return btrfs_match_dir_item_name(root, path, name, name_len);
 231 }
 232
 233 struct btrfs_dir_item *btrfs_lookup_dir_index(struct btrfs_trans_handle *trans,
 234                                               struct btrfs_root *root,
 235                                               struct btrfs_path *path, u64 dir,
 236                                               const char *name, int name_len,
 237                                               u64 index, int mod)
 238 {
 239         int ret;
 240         struct btrfs_key key;
 241         int ins_len = mod < 0 ? -1 : 0;
 242         int cow = mod != 0;
 243
 244         key.objectid = dir;
 245         key.type = BTRFS_DIR_INDEX_KEY;
 246         key.offset = index;
 247
 248         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 249         if (ret < 0)
 250                 return ERR_PTR(ret);
 251         if (ret > 0)
 252                 return ERR_PTR(-ENOENT);
 253
 254         return btrfs_match_dir_item_name(root, path, name, name_len);
 255 }
 256
 257 /*
 258  * given a pointer into a directory item, delete it.  This
 259  * handles items that have more than one entry in them.
 260  */
 261 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 262                               struct btrfs_root *root,
 263                               struct btrfs_path *path,
 264                               struct btrfs_dir_item *di)
 265 {
 266         struct extent_buffer *leaf;
 267         u32 sub_item_len;
 268         u32 item_len;
 269         int ret = 0;
 270
 271         leaf = path->nodes[0];
 272         sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
 273                 btrfs_dir_data_len(leaf, di);
 274         item_len = btrfs_item_size_nr(leaf, path->slots[0]);
 275
 276         /*
 277          * If @sub_item_len is longer than @item_len, then it means the
 278          * name_len is just corrupted.
 279          * No good idea to know if there is anything we can recover from
 280          * the corrupted item.
 281          * Just delete the item.
 282          */
 283         if (sub_item_len >= item_len) {
 284                 ret = btrfs_del_item(trans, root, path);
 285         } else {
 286                 unsigned long ptr = (unsigned long)di;
 287                 unsigned long start;
 288
 289                 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 290                 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 291                         item_len - (ptr + sub_item_len - start));
 292                 btrfs_truncate_item(root, path, item_len - sub_item_len, 1);
 293         }
 294         return ret;
 295 }
 296
 297 static int verify_dir_item(struct btrfs_root *root,
 298                     struct extent_buffer *leaf,
 299                     struct btrfs_dir_item *dir_item)
 300 {
 301         u16 namelen = BTRFS_NAME_LEN;
 302         u8 type = btrfs_dir_type(leaf, dir_item);
 303
 304         if (type == BTRFS_FT_XATTR)
 305                 namelen = XATTR_NAME_MAX;
 306
 307         if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
 308                 fprintf(stderr, "invalid dir item name len: %u\n",
 309                        (unsigned)btrfs_dir_data_len(leaf, dir_item));
 310                 return 1;
 311         }
 312
 313         /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
 314         if ((btrfs_dir_data_len(leaf, dir_item) +
 315              btrfs_dir_name_len(leaf, dir_item)) >
 316                         BTRFS_MAX_XATTR_SIZE(root->fs_info)) {
 317                 fprintf(stderr, "invalid dir item name + data len: %u + %u\n",
 318                        (unsigned)btrfs_dir_name_len(leaf, dir_item),
 319                        (unsigned)btrfs_dir_data_len(leaf, dir_item));
 320                 return 1;
 321         }
 322
 323         return 0;
 324 }
 325
 326 static struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 327                               struct btrfs_path *path,
 328                               const char *name, int name_len)
 329 {
 330         struct btrfs_dir_item *dir_item;
 331         unsigned long name_ptr;
 332         u32 total_len;
 333         u32 cur = 0;
 334         u32 this_len;
 335         struct extent_buffer *leaf;
 336
 337         leaf = path->nodes[0];
 338         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 339         total_len = btrfs_item_size_nr(leaf, path->slots[0]);
 340         if (verify_dir_item(root, leaf, dir_item))
 341                 return NULL;
 342
 343         while(cur < total_len) {
 344                 this_len = sizeof(*dir_item) +
 345                         btrfs_dir_name_len(leaf, dir_item) +
 346                         btrfs_dir_data_len(leaf, dir_item);
 347                 if (this_len > (total_len - cur)) {
 348                         fprintf(stderr, "invalid dir item size\n");
 349                         return NULL;
 350                 }
 351
 352                 name_ptr = (unsigned long)(dir_item + 1);
 353
 354                 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
 355                     memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
 356                         return dir_item;
 357
 358                 cur += this_len;
 359                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 360                                                      this_len);
 361         }
 362         return NULL;
 363 }