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_insert_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         unsigned long ptr;
  61         int ret;
  62         int ins_len = name_len + sizeof(*ref);
  63
  64         key.objectid = inode_objectid;
  65         key.offset = ref_objectid;
  66         btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
  67
  68         path = btrfs_alloc_path();
  69         if (!path)
  70                 return -ENOMEM;
  71
  72         ret = btrfs_insert_empty_item(trans, root, path, &key,
  73                                       ins_len);
  74         if (ret == -EEXIST) {
  75                 u32 old_size;
  76
  77                 if (find_name_in_backref(path, name, name_len, &ref))
  78                         goto out;
  79
  80                 old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
  81                 ret = btrfs_extend_item(trans, root, path, ins_len);
  82                 BUG_ON(ret);
  83                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
  84                                      struct btrfs_inode_ref);
  85                 ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
  86                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
  87                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
  88                 ptr = (unsigned long)(ref + 1);
  89                 ret = 0;
  90         } else if (ret < 0) {
  91                 goto out;
  92         } else {
  93                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
  94                                      struct btrfs_inode_ref);
  95                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
  96                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
  97                 ptr = (unsigned long)(ref + 1);
  98         }
  99         write_extent_buffer(path->nodes[0], name, ptr, name_len);
 100         btrfs_mark_buffer_dirty(path->nodes[0]);
 101
 102 out:
 103         btrfs_free_path(path);
 104         return ret;
 105 }
 106
 107 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 108                        *root, struct btrfs_path *path,
 109                        struct btrfs_key *location, int mod)
 110 {
 111         int ins_len = mod < 0 ? -1 : 0;
 112         int cow = mod != 0;
 113         int ret;
 114         int slot;
 115         struct extent_buffer *leaf;
 116         struct btrfs_key found_key;
 117
 118         ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
 119         if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
 120             location->offset == (u64)-1 && path->slots[0] != 0) {
 121                 slot = path->slots[0] - 1;
 122                 leaf = path->nodes[0];
 123                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
 124                 if (found_key.objectid == location->objectid &&
 125                     btrfs_key_type(&found_key) == btrfs_key_type(location)) {
 126                         path->slots[0]--;
 127                         return 0;
 128                 }
 129         }
 130         return ret;
 131 }
 132
 133 int btrfs_insert_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 134                        *root, u64 objectid, struct btrfs_inode_item
 135                        *inode_item)
 136 {
 137         int ret;
 138         struct btrfs_key key;
 139
 140         key.objectid = objectid;
 141         key.type = BTRFS_INODE_ITEM_KEY;
 142         key.offset = 0;
 143
 144         ret = btrfs_insert_item(trans, root, &key, inode_item,
 145                                 sizeof(*inode_item));
 146         return ret;
 147 }