fs/btrfs/inode-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 "transaction.h"
  22
  23 static int find_name_in_backref(struct btrfs_path *path, const char *name,
  24                          int name_len, struct btrfs_inode_ref **ref_ret)
  25 {
  26         struct extent_buffer *leaf;
  27         struct btrfs_inode_ref *ref;
  28         unsigned long ptr;
  29         unsigned long name_ptr;
  30         u32 item_size;
  31         u32 cur_offset = 0;
  32         int len;
  33
  34         leaf = path->nodes[0];
  35         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
  36         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
  37         while (cur_offset < item_size) {
  38                 ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
  39                 len = btrfs_inode_ref_name_len(leaf, ref);
  40                 name_ptr = (unsigned long)(ref + 1);
  41                 cur_offset += len + sizeof(*ref);
  42                 if (len != name_len)
  43                         continue;
  44                 if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
  45                         *ref_ret = ref;
  46                         return 1;
  47                 }
  48         }
  49         return 0;
  50 }
  51
  52 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
  53                            struct btrfs_root *root,
  54                            const char *name, int name_len,
  55                            u64 inode_objectid, u64 ref_objectid, u64 *index)
  56 {
  57         struct btrfs_path *path;
  58         struct btrfs_key key;
  59         struct btrfs_inode_ref *ref;
  60         struct extent_buffer *leaf;
  61         unsigned long ptr;
  62         unsigned long item_start;
  63         u32 item_size;
  64         u32 sub_item_len;
  65         int ret;
  66         int del_len = name_len + sizeof(*ref);
  67
  68         key.objectid = inode_objectid;
  69         key.offset = ref_objectid;
  70         btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
  71
  72         path = btrfs_alloc_path();
  73         if (!path)
  74                 return -ENOMEM;
  75
  76         path->leave_spinning = 1;
  77
  78         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
  79         if (ret > 0) {
  80                 ret = -ENOENT;
  81                 goto out;
  82         } else if (ret < 0) {
  83                 goto out;
  84         }
  85         if (!find_name_in_backref(path, name, name_len, &ref)) {
  86                 ret = -ENOENT;
  87                 goto out;
  88         }
  89         leaf = path->nodes[0];
  90         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
  91
  92         if (index)
  93                 *index = btrfs_inode_ref_index(leaf, ref);
  94
  95         if (del_len == item_size) {
  96                 ret = btrfs_del_item(trans, root, path);
  97                 goto out;
  98         }
  99         ptr = (unsigned long)ref;
 100         sub_item_len = name_len + sizeof(*ref);
 101         item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 102         memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 103                               item_size - (ptr + sub_item_len - item_start));
 104         ret = btrfs_truncate_item(trans, root, path,
 105                                   item_size - sub_item_len, 1);
 106         BUG_ON(ret);
 107 out:
 108         btrfs_free_path(path);
 109         return ret;
 110 }
 111
 112 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 113                            struct btrfs_root *root,
 114                            const char *name, int name_len,
 115                            u64 inode_objectid, u64 ref_objectid, u64 index)
 116 {
 117         struct btrfs_path *path;
 118         struct btrfs_key key;
 119         struct btrfs_inode_ref *ref;
 120         unsigned long ptr;
 121         int ret;
 122         int ins_len = name_len + sizeof(*ref);
 123
 124         key.objectid = inode_objectid;
 125         key.offset = ref_objectid;
 126         btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
 127
 128         path = btrfs_alloc_path();
 129         if (!path)
 130                 return -ENOMEM;
 131
 132         path->leave_spinning = 1;
 133         ret = btrfs_insert_empty_item(trans, root, path, &key,
 134                                       ins_len);
 135         if (ret == -EEXIST) {
 136                 u32 old_size;
 137
 138                 if (find_name_in_backref(path, name, name_len, &ref))
 139                         goto out;
 140
 141                 old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
 142                 ret = btrfs_extend_item(trans, root, path, ins_len);
 143                 BUG_ON(ret);
 144                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 145                                      struct btrfs_inode_ref);
 146                 ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
 147                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
 148                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
 149                 ptr = (unsigned long)(ref + 1);
 150                 ret = 0;
 151         } else if (ret < 0) {
 152                 if (ret == -EOVERFLOW)
 153                         ret = -EMLINK;
 154                 goto out;
 155         } else {
 156                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 157                                      struct btrfs_inode_ref);
 158                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
 159                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
 160                 ptr = (unsigned long)(ref + 1);
 161         }
 162         write_extent_buffer(path->nodes[0], name, ptr, name_len);
 163         btrfs_mark_buffer_dirty(path->nodes[0]);
 164
 165 out:
 166         btrfs_free_path(path);
 167         return ret;
 168 }
 169
 170 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
 171                              struct btrfs_root *root,
 172                              struct btrfs_path *path, u64 objectid)
 173 {
 174         struct btrfs_key key;
 175         int ret;
 176         key.objectid = objectid;
 177         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
 178         key.offset = 0;
 179
 180         ret = btrfs_insert_empty_item(trans, root, path, &key,
 181                                       sizeof(struct btrfs_inode_item));
 182         return ret;
 183 }
 184
 185 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 186                        *root, struct btrfs_path *path,
 187                        struct btrfs_key *location, int mod)
 188 {
 189         int ins_len = mod < 0 ? -1 : 0;
 190         int cow = mod != 0;
 191         int ret;
 192         int slot;
 193         struct extent_buffer *leaf;
 194         struct btrfs_key found_key;
 195
 196         ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
 197         if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
 198             location->offset == (u64)-1 && path->slots[0] != 0) {
 199                 slot = path->slots[0] - 1;
 200                 leaf = path->nodes[0];
 201                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
 202                 if (found_key.objectid == location->objectid &&
 203                     btrfs_key_type(&found_key) == btrfs_key_type(location)) {
 204                         path->slots[0]--;
 205                         return 0;
 206                 }
 207         }
 208         return ret;
 209 }