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 static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
  25                                                    *trans,
  26                                                    struct btrfs_root *root,
  27                                                    struct btrfs_path *path,
  28                                                    struct btrfs_key *cpu_key,
  29                                                    u32 data_size,
  30                                                    const char *name,
  31                                                    int name_len)
  32 {
  33         int ret;
  34         char *ptr;
  35         struct btrfs_item *item;
  36         struct extent_buffer *leaf;
  37
  38         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
  39         if (ret == -EEXIST) {
  40                 struct btrfs_dir_item *di;
  41                 di = btrfs_match_dir_item_name(root, path, name, name_len);
  42                 if (di)
  43                         return ERR_PTR(-EEXIST);
  44                 ret = btrfs_extend_item(trans, root, path, data_size);
  45                 WARN_ON(ret > 0);
  46         }
  47         if (ret < 0)
  48                 return ERR_PTR(ret);
  49         WARN_ON(ret > 0);
  50         leaf = path->nodes[0];
  51         item = btrfs_item_nr(leaf, path->slots[0]);
  52         ptr = btrfs_item_ptr(leaf, path->slots[0], char);
  53         BUG_ON(data_size > btrfs_item_size(leaf, item));
  54         ptr += btrfs_item_size(leaf, item) - data_size;
  55         return (struct btrfs_dir_item *)ptr;
  56 }
  57
  58 int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
  59                             struct btrfs_root *root, const char *name,
  60                             u16 name_len, const void *data, u16 data_len,
  61                             u64 dir)
  62 {
  63         int ret = 0;
  64         struct btrfs_path *path;
  65         struct btrfs_dir_item *dir_item;
  66         unsigned long name_ptr, data_ptr;
  67         struct btrfs_key key, location;
  68         struct btrfs_disk_key disk_key;
  69         struct extent_buffer *leaf;
  70         u32 data_size;
  71
  72         key.objectid = dir;
  73         btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
  74         key.offset = btrfs_name_hash(name, name_len);
  75         path = btrfs_alloc_path();
  76         if (!path)
  77                 return -ENOMEM;
  78         if (name_len + data_len + sizeof(struct btrfs_dir_item) >
  79             BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item))
  80                 return -ENOSPC;
  81
  82         data_size = sizeof(*dir_item) + name_len + data_len;
  83         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
  84                                         name, name_len);
  85         /*
  86          * FIXME: at some point we should handle xattr's that are larger than
  87          * what we can fit in our leaf.  We set location to NULL b/c we arent
  88          * pointing at anything else, that will change if we store the xattr
  89          * data in a separate inode.
  90          */
  91         BUG_ON(IS_ERR(dir_item));
  92         memset(&location, 0, sizeof(location));
  93
  94         leaf = path->nodes[0];
  95         btrfs_cpu_key_to_disk(&disk_key, &location);
  96         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
  97         btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
  98         btrfs_set_dir_name_len(leaf, dir_item, name_len);
  99         btrfs_set_dir_data_len(leaf, dir_item, data_len);
 100         name_ptr = (unsigned long)(dir_item + 1);
 101         data_ptr = (unsigned long)((char *)name_ptr + name_len);
 102
 103         write_extent_buffer(leaf, name, name_ptr, name_len);
 104         write_extent_buffer(leaf, data, data_ptr, data_len);
 105         btrfs_mark_buffer_dirty(path->nodes[0]);
 106
 107         btrfs_free_path(path);
 108         return ret;
 109 }
 110
 111 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 112                           *root, const char *name, int name_len, u64 dir,
 113                           struct btrfs_key *location, u8 type)
 114 {
 115         int ret = 0;
 116         int ret2 = 0;
 117         struct btrfs_path *path;
 118         struct btrfs_dir_item *dir_item;
 119         struct extent_buffer *leaf;
 120         unsigned long name_ptr;
 121         struct btrfs_key key;
 122         struct btrfs_disk_key disk_key;
 123         u32 data_size;
 124
 125         key.objectid = dir;
 126         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 127         key.offset = btrfs_name_hash(name, name_len);
 128         path = btrfs_alloc_path();
 129         data_size = sizeof(*dir_item) + name_len;
 130         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 131                                         name, name_len);
 132         if (IS_ERR(dir_item)) {
 133                 ret = PTR_ERR(dir_item);
 134                 if (ret == -EEXIST)
 135                         goto second_insert;
 136                 goto out;
 137         }
 138
 139         leaf = path->nodes[0];
 140         btrfs_cpu_key_to_disk(&disk_key, location);
 141         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 142         btrfs_set_dir_type(leaf, dir_item, type);
 143         btrfs_set_dir_data_len(leaf, dir_item, 0);
 144         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 145         name_ptr = (unsigned long)(dir_item + 1);
 146
 147         write_extent_buffer(leaf, name, name_ptr, name_len);
 148         btrfs_mark_buffer_dirty(leaf);
 149
 150 second_insert:
 151         /* FIXME, use some real flag for selecting the extra index */
 152         if (root == root->fs_info->tree_root) {
 153                 ret = 0;
 154                 goto out;
 155         }
 156         btrfs_release_path(root, path);
 157
 158         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 159         key.offset = location->objectid;
 160         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 161                                         name, name_len);
 162         if (IS_ERR(dir_item)) {
 163                 ret2 = PTR_ERR(dir_item);
 164                 goto out;
 165         }
 166         leaf = path->nodes[0];
 167         btrfs_cpu_key_to_disk(&disk_key, location);
 168         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 169         btrfs_set_dir_type(leaf, dir_item, type);
 170         btrfs_set_dir_data_len(leaf, dir_item, 0);
 171         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 172         name_ptr = (unsigned long)(dir_item + 1);
 173         write_extent_buffer(leaf, name, name_ptr, name_len);
 174         btrfs_mark_buffer_dirty(leaf);
 175 out:
 176         btrfs_free_path(path);
 177         if (ret)
 178                 return ret;
 179         if (ret2)
 180                 return ret2;
 181         return 0;
 182 }
 183
 184 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 185                                              struct btrfs_root *root,
 186                                              struct btrfs_path *path, u64 dir,
 187                                              const char *name, int name_len,
 188                                              int mod)
 189 {
 190         int ret;
 191         struct btrfs_key key;
 192         int ins_len = mod < 0 ? -1 : 0;
 193         int cow = mod != 0;
 194         struct btrfs_key found_key;
 195         struct extent_buffer *leaf;
 196
 197         key.objectid = dir;
 198         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 199
 200         key.offset = btrfs_name_hash(name, name_len);
 201
 202         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 203         if (ret < 0)
 204                 return ERR_PTR(ret);
 205         if (ret > 0) {
 206                 if (path->slots[0] == 0)
 207                         return NULL;
 208                 path->slots[0]--;
 209         }
 210
 211         leaf = path->nodes[0];
 212         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 213
 214         if (found_key.objectid != dir ||
 215             btrfs_key_type(&found_key) != BTRFS_DIR_ITEM_KEY ||
 216             found_key.offset != key.offset)
 217                 return NULL;
 218
 219         return btrfs_match_dir_item_name(root, path, name, name_len);
 220 }
 221
 222 struct btrfs_dir_item *
 223 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 224                             struct btrfs_root *root,
 225                             struct btrfs_path *path, u64 dir,
 226                             u64 objectid, const char *name, int name_len,
 227                             int mod)
 228 {
 229         int ret;
 230         struct btrfs_key key;
 231         int ins_len = mod < 0 ? -1 : 0;
 232         int cow = mod != 0;
 233
 234         key.objectid = dir;
 235         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 236         key.offset = objectid;
 237
 238         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 239         if (ret < 0)
 240                 return ERR_PTR(ret);
 241         if (ret > 0)
 242                 return ERR_PTR(-ENOENT);
 243         return btrfs_match_dir_item_name(root, path, name, name_len);
 244 }
 245
 246 struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
 247                                           struct btrfs_root *root,
 248                                           struct btrfs_path *path, u64 dir,
 249                                           const char *name, u16 name_len,
 250                                           int mod)
 251 {
 252         int ret;
 253         struct btrfs_key key;
 254         int ins_len = mod < 0 ? -1 : 0;
 255         int cow = mod != 0;
 256         struct btrfs_key found_key;
 257         struct extent_buffer *leaf;
 258
 259         key.objectid = dir;
 260         btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
 261         key.offset = btrfs_name_hash(name, name_len);
 262         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 263         if (ret < 0)
 264                 return ERR_PTR(ret);
 265         if (ret > 0) {
 266                 if (path->slots[0] == 0)
 267                         return NULL;
 268                 path->slots[0]--;
 269         }
 270
 271         leaf = path->nodes[0];
 272         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 273
 274         if (found_key.objectid != dir ||
 275             btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY ||
 276             found_key.offset != key.offset)
 277                 return NULL;
 278
 279         return btrfs_match_dir_item_name(root, path, name, name_len);
 280 }
 281
 282 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 283                               struct btrfs_path *path,
 284                               const char *name, int name_len)
 285 {
 286         struct btrfs_dir_item *dir_item;
 287         unsigned long name_ptr;
 288         u32 total_len;
 289         u32 cur = 0;
 290         u32 this_len;
 291         struct extent_buffer *leaf;
 292
 293         leaf = path->nodes[0];
 294         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 295         total_len = btrfs_item_size_nr(leaf, path->slots[0]);
 296         while(cur < total_len) {
 297                 this_len = sizeof(*dir_item) +
 298                         btrfs_dir_name_len(leaf, dir_item) +
 299                         btrfs_dir_data_len(leaf, dir_item);
 300                 name_ptr = (unsigned long)(dir_item + 1);
 301
 302                 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
 303                     memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
 304                         return dir_item;
 305
 306                 cur += this_len;
 307                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 308                                                      this_len);
 309         }
 310         return NULL;
 311 }
 312
 313 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 314                               struct btrfs_root *root,
 315                               struct btrfs_path *path,
 316                               struct btrfs_dir_item *di)
 317 {
 318
 319         struct extent_buffer *leaf;
 320         u32 sub_item_len;
 321         u32 item_len;
 322         int ret = 0;
 323
 324         leaf = path->nodes[0];
 325         sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
 326                 btrfs_dir_data_len(leaf, di);
 327         item_len = btrfs_item_size_nr(leaf, path->slots[0]);
 328         if (sub_item_len == item_len) {
 329                 ret = btrfs_del_item(trans, root, path);
 330         } else {
 331                 /* MARKER */
 332                 unsigned long ptr = (unsigned long)di;
 333                 unsigned long start;
 334
 335                 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 336                 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 337                         item_len - (ptr + sub_item_len - start));
 338                 ret = btrfs_truncate_item(trans, root, path,
 339                                           item_len - sub_item_len, 1);
 340         }
 341         return 0;
 342 }
 343