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                 if (ret)
  47                         return ERR_PTR(ret);
  48         }
  49         if (ret < 0)
  50                 return ERR_PTR(ret);
  51         WARN_ON(ret > 0);
  52         leaf = path->nodes[0];
  53         item = btrfs_item_nr(leaf, path->slots[0]);
  54         ptr = btrfs_item_ptr(leaf, path->slots[0], char);
  55         BUG_ON(data_size > btrfs_item_size(leaf, item));
  56         ptr += btrfs_item_size(leaf, 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         struct extent_buffer *leaf;
  69         unsigned long name_ptr;
  70         struct btrfs_key key;
  71         struct btrfs_disk_key disk_key;
  72         u32 data_size;
  73
  74         key.objectid = dir;
  75         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
  76         ret = btrfs_name_hash(name, name_len, &key.offset);
  77         BUG_ON(ret);
  78         path = btrfs_alloc_path();
  79         data_size = sizeof(*dir_item) + name_len;
  80         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
  81                                         name, name_len);
  82         if (IS_ERR(dir_item)) {
  83                 ret = PTR_ERR(dir_item);
  84                 if (ret == -EEXIST)
  85                         goto second_insert;
  86                 goto out;
  87         }
  88
  89         leaf = path->nodes[0];
  90         btrfs_cpu_key_to_disk(&disk_key, location);
  91         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
  92         btrfs_set_dir_type(leaf, dir_item, type);
  93         btrfs_set_dir_flags(leaf, dir_item, 0);
  94         btrfs_set_dir_name_len(leaf, dir_item, name_len);
  95         name_ptr = (unsigned long)(dir_item + 1);
  96
  97         write_extent_buffer(leaf, name, name_ptr, name_len);
  98         btrfs_mark_buffer_dirty(leaf);
  99
 100 second_insert:
 101         /* FIXME, use some real flag for selecting the extra index */
 102         if (root == root->fs_info->tree_root) {
 103                 ret = 0;
 104                 goto out;
 105         }
 106         btrfs_release_path(root, path);
 107
 108         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 109         key.offset = location->objectid;
 110         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
 111                                         name, name_len);
 112         if (IS_ERR(dir_item)) {
 113                 ret2 = PTR_ERR(dir_item);
 114                 goto out;
 115         }
 116         leaf = path->nodes[0];
 117         btrfs_cpu_key_to_disk(&disk_key, location);
 118         btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
 119         btrfs_set_dir_type(leaf, dir_item, type);
 120         btrfs_set_dir_flags(leaf, dir_item, 0);
 121         btrfs_set_dir_name_len(leaf, dir_item, name_len);
 122         name_ptr = (unsigned long)(dir_item + 1);
 123         write_extent_buffer(leaf, name, name_ptr, name_len);
 124         btrfs_mark_buffer_dirty(leaf);
 125 out:
 126         btrfs_free_path(path);
 127         if (ret)
 128                 return ret;
 129         if (ret2)
 130                 return ret2;
 131         return 0;
 132 }
 133
 134 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 135                                              struct btrfs_root *root,
 136                                              struct btrfs_path *path, u64 dir,
 137                                              const char *name, int name_len,
 138                                              int mod)
 139 {
 140         int ret;
 141         struct btrfs_key key;
 142         int ins_len = mod < 0 ? -1 : 0;
 143         int cow = mod != 0;
 144         struct btrfs_key found_key;
 145         struct extent_buffer *leaf;
 146
 147         key.objectid = dir;
 148         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 149
 150         ret = btrfs_name_hash(name, name_len, &key.offset);
 151         BUG_ON(ret);
 152
 153         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 154         if (ret < 0)
 155                 return ERR_PTR(ret);
 156         if (ret > 0) {
 157                 if (path->slots[0] == 0)
 158                         return NULL;
 159                 path->slots[0]--;
 160         }
 161
 162         leaf = path->nodes[0];
 163         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 164
 165         if (found_key.objectid != dir ||
 166             btrfs_key_type(&found_key) != BTRFS_DIR_ITEM_KEY ||
 167             found_key.offset != key.offset)
 168                 return NULL;
 169
 170         return btrfs_match_dir_item_name(root, path, name, name_len);
 171 }
 172
 173 struct btrfs_dir_item *
 174 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 175                             struct btrfs_root *root,
 176                             struct btrfs_path *path, u64 dir,
 177                             u64 objectid, const char *name, int name_len,
 178                             int mod)
 179 {
 180         int ret;
 181         struct btrfs_key key;
 182         int ins_len = mod < 0 ? -1 : 0;
 183         int cow = mod != 0;
 184
 185         key.objectid = dir;
 186         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 187         key.offset = objectid;
 188
 189         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 190         if (ret < 0)
 191                 return ERR_PTR(ret);
 192         if (ret > 0)
 193                 return ERR_PTR(-ENOENT);
 194         return btrfs_match_dir_item_name(root, path, name, name_len);
 195 }
 196
 197 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 198                               struct btrfs_path *path,
 199                               const char *name, int name_len)
 200 {
 201         struct btrfs_dir_item *dir_item;
 202         unsigned long name_ptr;
 203         u32 total_len;
 204         u32 cur = 0;
 205         u32 this_len;
 206         struct extent_buffer *leaf;
 207
 208         leaf = path->nodes[0];
 209         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 210         total_len = btrfs_item_size_nr(leaf, path->slots[0]);
 211         while(cur < total_len) {
 212                 this_len = sizeof(*dir_item) +
 213                         btrfs_dir_name_len(leaf, dir_item);
 214                 name_ptr = (unsigned long)(dir_item + 1);
 215
 216                 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
 217                     memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
 218                         return dir_item;
 219
 220                 cur += this_len;
 221                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 222                                                      this_len);
 223         }
 224         return NULL;
 225 }
 226
 227 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 228                               struct btrfs_root *root,
 229                               struct btrfs_path *path,
 230                               struct btrfs_dir_item *di)
 231 {
 232
 233         struct extent_buffer *leaf;
 234         u32 sub_item_len;
 235         u32 item_len;
 236         int ret = 0;
 237
 238         leaf = path->nodes[0];
 239         sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di);
 240         item_len = btrfs_item_size_nr(leaf, path->slots[0]);
 241         if (sub_item_len == item_len) {
 242                 ret = btrfs_del_item(trans, root, path);
 243         } else {
 244                 /* MARKER */
 245                 unsigned long ptr = (unsigned long)di;
 246                 unsigned long start;
 247
 248                 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 249                 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 250                         item_len - (ptr + sub_item_len - start));
 251                 ret = btrfs_truncate_item(trans, root, path,
 252                                           item_len - sub_item_len);
 253         }
 254         return 0;
 255 }
 256