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         ret = btrfs_name_hash(name, name_len, &key.offset);
  75         BUG_ON(ret);
  76         path = btrfs_alloc_path();
  77         if (!path)
  78                 return -ENOMEM;
  79
  80         data_size = sizeof(*dir_item) + name_len + data_len;
  81         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
  82                                         name, name_len);
  83         /*
  84          * FIXME: at some point we should handle xattr's that are larger than
  85          * what we can fit in our leaf.  We set location to NULL b/c we arent
  86          * pointing at anything else, that will change if we store the xattr
  87          * data in a separate inode.
  88          */
  89         BUG_ON(IS_ERR(dir_item));
  90         memset(&location, 0, sizeof(location));
  91
  92         leaf = path->nodes[0];
  93         btrfs_cpu_key_to_disk(&disk_key, &location);
  94         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
  95         btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
  96         btrfs_set_dir_name_len(leaf, dir_item, name_len);
  97         btrfs_set_dir_data_len(leaf, dir_item, data_len);
  98         name_ptr = (unsigned long)(dir_item + 1);
  99         data_ptr = (unsigned long)((char *)name_ptr + name_len);
 100
 101         write_extent_buffer(leaf, name, name_ptr, name_len);
 102         write_extent_buffer(leaf, data, data_ptr, data_len);
 103         btrfs_mark_buffer_dirty(path->nodes[0]);
 104
 105         btrfs_free_path(path);
 106         return ret;
 107 }
 108
 109 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 110                           *root, const char *name, int name_len, u64 dir,
 111                           struct btrfs_key *location, u8 type)
 112 {
 113         int ret = 0;
 114         int ret2 = 0;
 115         struct btrfs_path *path;
 116         struct btrfs_dir_item *dir_item;
 117         struct extent_buffer *leaf;
 118         unsigned long name_ptr;
 119         struct btrfs_key key;
 120         struct btrfs_disk_key disk_key;
 121         u32 data_size;
 122
 123         key.objectid = dir;
 124         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 125         ret = btrfs_name_hash(name, name_len, &key.offset);
 126         BUG_ON(ret);
 127         path = btrfs_alloc_path();
 128         data_size = sizeof(*dir_item) + name_len;
 129         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 130                                         name, name_len);
 131         if (IS_ERR(dir_item)) {
 132                 ret = PTR_ERR(dir_item);
 133                 if (ret == -EEXIST)
 134                         goto second_insert;
 135                 goto out;
 136         }
 137
 138         leaf = path->nodes[0];
 139         btrfs_cpu_key_to_disk(&disk_key, location);
 140         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 141         btrfs_set_dir_type(leaf, dir_item, type);
 142         btrfs_set_dir_data_len(leaf, dir_item, 0);
 143         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 144         name_ptr = (unsigned long)(dir_item + 1);
 145
 146         write_extent_buffer(leaf, name, name_ptr, name_len);
 147         btrfs_mark_buffer_dirty(leaf);
 148
 149 second_insert:
 150         /* FIXME, use some real flag for selecting the extra index */
 151         if (root == root->fs_info->tree_root) {
 152                 ret = 0;
 153                 goto out;
 154         }
 155         btrfs_release_path(root, path);
 156
 157         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 158         key.offset = location->objectid;
 159         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 160                                         name, name_len);
 161         if (IS_ERR(dir_item)) {
 162                 ret2 = PTR_ERR(dir_item);
 163                 goto out;
 164         }
 165         leaf = path->nodes[0];
 166         btrfs_cpu_key_to_disk(&disk_key, location);
 167         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 168         btrfs_set_dir_type(leaf, dir_item, type);
 169         btrfs_set_dir_data_len(leaf, dir_item, 0);
 170         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 171         name_ptr = (unsigned long)(dir_item + 1);
 172         write_extent_buffer(leaf, name, name_ptr, name_len);
 173         btrfs_mark_buffer_dirty(leaf);
 174 out:
 175         btrfs_free_path(path);
 176         if (ret)
 177                 return ret;
 178         if (ret2)
 179                 return ret2;
 180         return 0;
 181 }
 182
 183 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 184                                              struct btrfs_root *root,
 185                                              struct btrfs_path *path, u64 dir,
 186                                              const char *name, int name_len,
 187                                              int mod)
 188 {
 189         int ret;
 190         struct btrfs_key key;
 191         int ins_len = mod < 0 ? -1 : 0;
 192         int cow = mod != 0;
 193         struct btrfs_key found_key;
 194         struct extent_buffer *leaf;
 195
 196         key.objectid = dir;
 197         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 198
 199         ret = btrfs_name_hash(name, name_len, &key.offset);
 200         BUG_ON(ret);
 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         ret = btrfs_name_hash(name, name_len, &key.offset);
 262         BUG_ON(ret);
 263         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 264         if (ret < 0)
 265                 return ERR_PTR(ret);
 266         if (ret > 0) {
 267                 if (path->slots[0] == 0)
 268                         return NULL;
 269                 path->slots[0]--;
 270         }
 271
 272         leaf = path->nodes[0];
 273         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 274
 275         if (found_key.objectid != dir ||
 276             btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY ||
 277             found_key.offset != key.offset)
 278                 return NULL;
 279
 280         return btrfs_match_dir_item_name(root, path, name, name_len);
 281 }
 282
 283 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 284                               struct btrfs_path *path,
 285                               const char *name, int name_len)
 286 {
 287         struct btrfs_dir_item *dir_item;
 288         unsigned long name_ptr;
 289         u32 total_len;
 290         u32 cur = 0;
 291         u32 this_len;
 292         struct extent_buffer *leaf;
 293
 294         leaf = path->nodes[0];
 295         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 296         total_len = btrfs_item_size_nr(leaf, path->slots[0]);
 297         while(cur < total_len) {
 298                 this_len = sizeof(*dir_item) +
 299                         btrfs_dir_name_len(leaf, dir_item) +
 300                         btrfs_dir_data_len(leaf, dir_item);
 301                 name_ptr = (unsigned long)(dir_item + 1);
 302
 303                 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
 304                     memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
 305                         return dir_item;
 306
 307                 cur += this_len;
 308                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 309                                                      this_len);
 310         }
 311         return NULL;
 312 }
 313
 314 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 315                               struct btrfs_root *root,
 316                               struct btrfs_path *path,
 317                               struct btrfs_dir_item *di)
 318 {
 319
 320         struct extent_buffer *leaf;
 321         u32 sub_item_len;
 322         u32 item_len;
 323         int ret = 0;
 324
 325         leaf = path->nodes[0];
 326         sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
 327                 btrfs_dir_data_len(leaf, di);
 328         item_len = btrfs_item_size_nr(leaf, path->slots[0]);
 329         if (sub_item_len == item_len) {
 330                 ret = btrfs_del_item(trans, root, path);
 331         } else {
 332                 /* MARKER */
 333                 unsigned long ptr = (unsigned long)di;
 334                 unsigned long start;
 335
 336                 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 337                 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 338                         item_len - (ptr + sub_item_len - start));
 339                 ret = btrfs_truncate_item(trans, root, path,
 340                                           item_len - sub_item_len, 1);
 341         }
 342         return 0;
 343 }
 344