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 *btrfs_match_dir_item_name(struct btrfs_root *root,
  25                               struct btrfs_path *path,
  26                               const char *name, int name_len);
  27
  28 static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
  29                                                    *trans,
  30                                                    struct btrfs_root *root,
  31                                                    struct btrfs_path *path,
  32                                                    struct btrfs_key *cpu_key,
  33                                                    u32 data_size,
  34                                                    const char *name,
  35                                                    int name_len)
  36 {
  37         int ret;
  38         char *ptr;
  39         struct btrfs_item *item;
  40         struct extent_buffer *leaf;
  41
  42         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
  43         if (ret == -EEXIST) {
  44                 struct btrfs_dir_item *di;
  45                 di = btrfs_match_dir_item_name(root, path, name, name_len);
  46                 if (di)
  47                         return ERR_PTR(-EEXIST);
  48                 ret = btrfs_extend_item(trans, root, path, data_size);
  49                 WARN_ON(ret > 0);
  50         }
  51         if (ret < 0)
  52                 return ERR_PTR(ret);
  53         WARN_ON(ret > 0);
  54         leaf = path->nodes[0];
  55         item = btrfs_item_nr(path->slots[0]);
  56         ptr = btrfs_item_ptr(leaf, path->slots[0], char);
  57         BUG_ON(data_size > btrfs_item_size(leaf, item));
  58         ptr += btrfs_item_size(leaf, item) - data_size;
  59         return (struct btrfs_dir_item *)ptr;
  60 }
  61
  62 int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
  63                             struct btrfs_root *root, const char *name,
  64                             u16 name_len, const void *data, u16 data_len,
  65                             u64 dir)
  66 {
  67         int ret = 0;
  68         struct btrfs_path *path;
  69         struct btrfs_dir_item *dir_item;
  70         unsigned long name_ptr, data_ptr;
  71         struct btrfs_key key, location;
  72         struct btrfs_disk_key disk_key;
  73         struct extent_buffer *leaf;
  74         u32 data_size;
  75
  76         key.objectid = dir;
  77         btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
  78         key.offset = btrfs_name_hash(name, name_len);
  79         path = btrfs_alloc_path();
  80         if (!path)
  81                 return -ENOMEM;
  82
  83         data_size = sizeof(*dir_item) + name_len + data_len;
  84         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
  85                                         name, name_len);
  86         /*
  87          * FIXME: at some point we should handle xattr's that are larger than
  88          * what we can fit in our leaf.  We set location to NULL b/c we arent
  89          * pointing at anything else, that will change if we store the xattr
  90          * data in a separate inode.
  91          */
  92         BUG_ON(IS_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_data_len(leaf, dir_item, data_len);
 101         name_ptr = (unsigned long)(dir_item + 1);
 102         data_ptr = (unsigned long)((char *)name_ptr + name_len);
 103
 104         write_extent_buffer(leaf, name, name_ptr, name_len);
 105         write_extent_buffer(leaf, data, data_ptr, data_len);
 106         btrfs_mark_buffer_dirty(path->nodes[0]);
 107
 108         btrfs_free_path(path);
 109         return ret;
 110 }
 111
 112 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 113                           *root, const char *name, int name_len, u64 dir,
 114                           struct btrfs_key *location, u8 type, u64 index)
 115 {
 116         int ret = 0;
 117         int ret2 = 0;
 118         struct btrfs_path *path;
 119         struct btrfs_dir_item *dir_item;
 120         struct extent_buffer *leaf;
 121         unsigned long name_ptr;
 122         struct btrfs_key key;
 123         struct btrfs_disk_key disk_key;
 124         u32 data_size;
 125
 126         key.objectid = dir;
 127         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 128         key.offset = btrfs_name_hash(name, name_len);
 129         path = btrfs_alloc_path();
 130         if (!path)
 131                 return -ENOMEM;
 132         data_size = sizeof(*dir_item) + name_len;
 133         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 134                                         name, name_len);
 135         if (IS_ERR(dir_item)) {
 136                 ret = PTR_ERR(dir_item);
 137                 goto out;
 138         }
 139
 140         leaf = path->nodes[0];
 141         btrfs_cpu_key_to_disk(&disk_key, location);
 142         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 143         btrfs_set_dir_type(leaf, dir_item, type);
 144         btrfs_set_dir_data_len(leaf, dir_item, 0);
 145         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 146         name_ptr = (unsigned long)(dir_item + 1);
 147
 148         write_extent_buffer(leaf, name, name_ptr, name_len);
 149         btrfs_mark_buffer_dirty(leaf);
 150
 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(path);
 157
 158         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 159         key.offset = index;
 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 static struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 223                               struct btrfs_path *path,
 224                               const char *name, int name_len)
 225 {
 226         struct btrfs_dir_item *dir_item;
 227         unsigned long name_ptr;
 228         u32 total_len;
 229         u32 cur = 0;
 230         u32 this_len;
 231         struct extent_buffer *leaf;
 232
 233         leaf = path->nodes[0];
 234         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 235         total_len = btrfs_item_size_nr(leaf, path->slots[0]);
 236         while(cur < total_len) {
 237                 this_len = sizeof(*dir_item) +
 238                         btrfs_dir_name_len(leaf, dir_item) +
 239                         btrfs_dir_data_len(leaf, dir_item);
 240                 name_ptr = (unsigned long)(dir_item + 1);
 241
 242                 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
 243                     memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
 244                         return dir_item;
 245
 246                 cur += this_len;
 247                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 248                                                      this_len);
 249         }
 250         return NULL;
 251 }