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