SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 <linux/module.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 *insert_with_overflow(struct btrfs_trans_handle
  26                                                    *trans,
  27                                                    struct btrfs_root *root,
  28                                                    struct btrfs_path *path,
  29                                                    struct btrfs_key *cpu_key,
  30                                                    u32 data_size,
  31                                                    const char *name,
  32                                                    int name_len)
  33 {
  34         int ret;
  35         char *ptr;
  36         struct btrfs_item *item;
  37         struct btrfs_leaf *leaf;
  38
  39         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
  40         if (ret == -EEXIST) {
  41                 struct btrfs_dir_item *di;
  42                 di = btrfs_match_dir_item_name(root, path, name, name_len);
  43                 if (di)
  44                         return ERR_PTR(-EEXIST);
  45                 ret = btrfs_extend_item(trans, root, path, data_size);
  46                 WARN_ON(ret > 0);
  47                 if (ret)
  48                         return ERR_PTR(ret);
  49         }
  50         WARN_ON(ret > 0);
  51         leaf = btrfs_buffer_leaf(path->nodes[0]);
  52         item = leaf->items + path->slots[0];
  53         ptr = btrfs_item_ptr(leaf, path->slots[0], char);
  54         BUG_ON(data_size > btrfs_item_size(item));
  55         ptr += btrfs_item_size(item) - data_size;
  56         return (struct btrfs_dir_item *)ptr;
  57 }
  58
  59 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
  60                           *root, const char *name, int name_len, u64 dir,
  61                           struct btrfs_key *location, u8 type)
  62 {
  63         int ret = 0;
  64         int ret2 = 0;
  65         struct btrfs_path *path;
  66         struct btrfs_dir_item *dir_item;
  67         char *name_ptr;
  68         struct btrfs_key key;
  69         u32 data_size;
  70
  71         key.objectid = dir;
  72         key.flags = 0;
  73         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
  74         ret = btrfs_name_hash(name, name_len, &key.offset);
  75         BUG_ON(ret);
  76         path = btrfs_alloc_path();
  77         data_size = sizeof(*dir_item) + name_len;
  78         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
  79                                         name, name_len);
  80         if (IS_ERR(dir_item)) {
  81                 ret = PTR_ERR(dir_item);
  82                 if (ret == -EEXIST)
  83                         goto second_insert;
  84                 goto out;
  85         }
  86
  87         btrfs_cpu_key_to_disk(&dir_item->location, location);
  88         btrfs_set_dir_type(dir_item, type);
  89         btrfs_set_dir_flags(dir_item, 0);
  90         btrfs_set_dir_name_len(dir_item, name_len);
  91         name_ptr = (char *)(dir_item + 1);
  92
  93         btrfs_memcpy(root, path->nodes[0]->b_data, name_ptr, name, name_len);
  94         btrfs_mark_buffer_dirty(path->nodes[0]);
  95
  96 second_insert:
  97         /* FIXME, use some real flag for selecting the extra index */
  98         if (root == root->fs_info->tree_root) {
  99                 ret = 0;
 100                 goto out;
 101         }
 102         btrfs_release_path(root, path);
 103
 104         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 105         key.offset = location->objectid;
 106         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 107                                         name, name_len);
 108         if (IS_ERR(dir_item)) {
 109                 ret2 = PTR_ERR(dir_item);
 110                 goto out;
 111         }
 112         btrfs_cpu_key_to_disk(&dir_item->location, location);
 113         btrfs_set_dir_type(dir_item, type);
 114         btrfs_set_dir_flags(dir_item, 0);
 115         btrfs_set_dir_name_len(dir_item, name_len);
 116         name_ptr = (char *)(dir_item + 1);
 117         btrfs_memcpy(root, path->nodes[0]->b_data, name_ptr, name, name_len);
 118         btrfs_mark_buffer_dirty(path->nodes[0]);
 119 out:
 120         btrfs_free_path(path);
 121         if (ret)
 122                 return ret;
 123         if (ret2)
 124                 return ret2;
 125         return 0;
 126 }
 127
 128 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 129                                              struct btrfs_root *root,
 130                                              struct btrfs_path *path, u64 dir,
 131                                              const char *name, int name_len,
 132                                              int mod)
 133 {
 134         int ret;
 135         struct btrfs_key key;
 136         int ins_len = mod < 0 ? -1 : 0;
 137         int cow = mod != 0;
 138         struct btrfs_disk_key *found_key;
 139         struct btrfs_leaf *leaf;
 140
 141         key.objectid = dir;
 142         key.flags = 0;
 143         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 144         ret = btrfs_name_hash(name, name_len, &key.offset);
 145         BUG_ON(ret);
 146         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 147         if (ret < 0)
 148                 return ERR_PTR(ret);
 149         if (ret > 0) {
 150                 if (path->slots[0] == 0)
 151                         return NULL;
 152                 path->slots[0]--;
 153         }
 154         leaf = btrfs_buffer_leaf(path->nodes[0]);
 155         found_key = &leaf->items[path->slots[0]].key;
 156
 157         if (btrfs_disk_key_objectid(found_key) != dir ||
 158             btrfs_disk_key_type(found_key) != BTRFS_DIR_ITEM_KEY ||
 159             btrfs_disk_key_offset(found_key) != key.offset)
 160                 return NULL;
 161
 162         return btrfs_match_dir_item_name(root, path, name, name_len);
 163 }
 164
 165 struct btrfs_dir_item *
 166 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 167                             struct btrfs_root *root,
 168                             struct btrfs_path *path, u64 dir,
 169                             u64 objectid, const char *name, int name_len,
 170                             int mod)
 171 {
 172         int ret;
 173         struct btrfs_key key;
 174         int ins_len = mod < 0 ? -1 : 0;
 175         int cow = mod != 0;
 176
 177         key.objectid = dir;
 178         key.flags = 0;
 179         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 180         key.offset = objectid;
 181
 182         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 183         if (ret < 0)
 184                 return ERR_PTR(ret);
 185         if (ret > 0)
 186                 return ERR_PTR(-ENOENT);
 187         return btrfs_match_dir_item_name(root, path, name, name_len);
 188 }
 189
 190 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 191                               struct btrfs_path *path,
 192                               const char *name, int name_len)
 193 {
 194         struct btrfs_dir_item *dir_item;
 195         char *name_ptr;
 196         u32 total_len;
 197         u32 cur = 0;
 198         u32 this_len;
 199         struct btrfs_leaf *leaf;
 200
 201         leaf = btrfs_buffer_leaf(path->nodes[0]);
 202         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 203         total_len = btrfs_item_size(leaf->items + path->slots[0]);
 204         while(cur < total_len) {
 205                 this_len = sizeof(*dir_item) + btrfs_dir_name_len(dir_item);
 206                 name_ptr = (char *)(dir_item + 1);
 207
 208                 if (btrfs_dir_name_len(dir_item) == name_len &&
 209                     memcmp(name_ptr, name, name_len) == 0)
 210                         return dir_item;
 211
 212                 cur += this_len;
 213                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 214                                                      this_len);
 215         }
 216         return NULL;
 217 }
 218
 219 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 220                               struct btrfs_root *root,
 221                               struct btrfs_path *path,
 222                               struct btrfs_dir_item *di)
 223 {
 224
 225         struct btrfs_leaf *leaf;
 226         u32 sub_item_len;
 227         u32 item_len;
 228         int ret;
 229
 230         leaf = btrfs_buffer_leaf(path->nodes[0]);
 231         sub_item_len = sizeof(*di) + btrfs_dir_name_len(di);
 232         item_len = btrfs_item_size(leaf->items + path->slots[0]);
 233         if (sub_item_len == btrfs_item_size(leaf->items + path->slots[0])) {
 234                 ret = btrfs_del_item(trans, root, path);
 235                 BUG_ON(ret);
 236         } else {
 237                 char *ptr = (char *)di;
 238                 char *start = btrfs_item_ptr(leaf, path->slots[0], char);
 239                 btrfs_memmove(root, leaf, ptr, ptr + sub_item_len,
 240                         item_len - (ptr + sub_item_len - start));
 241                 ret = btrfs_truncate_item(trans, root, path,
 242                                           item_len - sub_item_len);
 243                 BUG_ON(ret);
 244         }
 245         return 0;
 246 }
 247