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 #include "print-tree.h"
  23
  24 static int find_name_in_backref(struct btrfs_path *path, const char *name,
  25                          int name_len, struct btrfs_inode_ref **ref_ret)
  26 {
  27         struct extent_buffer *leaf;
  28         struct btrfs_inode_ref *ref;
  29         unsigned long ptr;
  30         unsigned long name_ptr;
  31         u32 item_size;
  32         u32 cur_offset = 0;
  33         int len;
  34
  35         leaf = path->nodes[0];
  36         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
  37         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
  38         while (cur_offset < item_size) {
  39                 ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
  40                 len = btrfs_inode_ref_name_len(leaf, ref);
  41                 name_ptr = (unsigned long)(ref + 1);
  42                 cur_offset += len + sizeof(*ref);
  43                 if (len != name_len)
  44                         continue;
  45                 if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
  46                         *ref_ret = ref;
  47                         return 1;
  48                 }
  49         }
  50         return 0;
  51 }
  52
  53 struct btrfs_inode_ref *
  54 btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
  55                         struct btrfs_root *root,
  56                         struct btrfs_path *path,
  57                         const char *name, int name_len,
  58                         u64 inode_objectid, u64 ref_objectid, int mod)
  59 {
  60         struct btrfs_key key;
  61         struct btrfs_inode_ref *ref;
  62         int ins_len = mod < 0 ? -1 : 0;
  63         int cow = mod != 0;
  64         int ret;
  65
  66         key.objectid = inode_objectid;
  67         key.type = BTRFS_INODE_REF_KEY;
  68         key.offset = ref_objectid;
  69
  70         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
  71         if (ret < 0)
  72                 return ERR_PTR(ret);
  73         if (ret > 0)
  74                 return NULL;
  75         if (!find_name_in_backref(path, name, name_len, &ref))
  76                 return NULL;
  77         return ref;
  78 }
  79
  80 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
  81                            struct btrfs_root *root,
  82                            const char *name, int name_len,
  83                            u64 inode_objectid, u64 ref_objectid, u64 *index)
  84 {
  85         struct btrfs_path *path;
  86         struct btrfs_key key;
  87         struct btrfs_inode_ref *ref;
  88         struct extent_buffer *leaf;
  89         unsigned long ptr;
  90         unsigned long item_start;
  91         u32 item_size;
  92         u32 sub_item_len;
  93         int ret;
  94         int del_len = name_len + sizeof(*ref);
  95
  96         key.objectid = inode_objectid;
  97         key.offset = ref_objectid;
  98         btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
  99
 100         path = btrfs_alloc_path();
 101         if (!path)
 102                 return -ENOMEM;
 103
 104         path->leave_spinning = 1;
 105
 106         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 107         if (ret > 0) {
 108                 ret = -ENOENT;
 109                 goto out;
 110         } else if (ret < 0) {
 111                 goto out;
 112         }
 113         if (!find_name_in_backref(path, name, name_len, &ref)) {
 114                 ret = -ENOENT;
 115                 goto out;
 116         }
 117         leaf = path->nodes[0];
 118         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 119
 120         if (index)
 121                 *index = btrfs_inode_ref_index(leaf, ref);
 122
 123         if (del_len == item_size) {
 124                 ret = btrfs_del_item(trans, root, path);
 125                 goto out;
 126         }
 127         ptr = (unsigned long)ref;
 128         sub_item_len = name_len + sizeof(*ref);
 129         item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 130         memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 131                               item_size - (ptr + sub_item_len - item_start));
 132         btrfs_truncate_item(trans, root, path,
 133                                   item_size - sub_item_len, 1);
 134 out:
 135         btrfs_free_path(path);
 136         return ret;
 137 }
 138
 139 /* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
 140 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 141                            struct btrfs_root *root,
 142                            const char *name, int name_len,
 143                            u64 inode_objectid, u64 ref_objectid, u64 index)
 144 {
 145         struct btrfs_path *path;
 146         struct btrfs_key key;
 147         struct btrfs_inode_ref *ref;
 148         unsigned long ptr;
 149         int ret;
 150         int ins_len = name_len + sizeof(*ref);
 151
 152         key.objectid = inode_objectid;
 153         key.offset = ref_objectid;
 154         btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
 155
 156         path = btrfs_alloc_path();
 157         if (!path)
 158                 return -ENOMEM;
 159
 160         path->leave_spinning = 1;
 161         ret = btrfs_insert_empty_item(trans, root, path, &key,
 162                                       ins_len);
 163         if (ret == -EEXIST) {
 164                 u32 old_size;
 165
 166                 if (find_name_in_backref(path, name, name_len, &ref))
 167                         goto out;
 168
 169                 old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
 170                 btrfs_extend_item(trans, root, path, ins_len);
 171                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 172                                      struct btrfs_inode_ref);
 173                 ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
 174                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
 175                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
 176                 ptr = (unsigned long)(ref + 1);
 177                 ret = 0;
 178         } else if (ret < 0) {
 179                 if (ret == -EOVERFLOW)
 180                         ret = -EMLINK;
 181                 goto out;
 182         } else {
 183                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 184                                      struct btrfs_inode_ref);
 185                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
 186                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
 187                 ptr = (unsigned long)(ref + 1);
 188         }
 189         write_extent_buffer(path->nodes[0], name, ptr, name_len);
 190         btrfs_mark_buffer_dirty(path->nodes[0]);
 191
 192 out:
 193         btrfs_free_path(path);
 194         return ret;
 195 }
 196
 197 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
 198                              struct btrfs_root *root,
 199                              struct btrfs_path *path, u64 objectid)
 200 {
 201         struct btrfs_key key;
 202         int ret;
 203         key.objectid = objectid;
 204         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
 205         key.offset = 0;
 206
 207         ret = btrfs_insert_empty_item(trans, root, path, &key,
 208                                       sizeof(struct btrfs_inode_item));
 209         return ret;
 210 }
 211
 212 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 213                        *root, struct btrfs_path *path,
 214                        struct btrfs_key *location, int mod)
 215 {
 216         int ins_len = mod < 0 ? -1 : 0;
 217         int cow = mod != 0;
 218         int ret;
 219         int slot;
 220         struct extent_buffer *leaf;
 221         struct btrfs_key found_key;
 222
 223         ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
 224         if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
 225             location->offset == (u64)-1 && path->slots[0] != 0) {
 226                 slot = path->slots[0] - 1;
 227                 leaf = path->nodes[0];
 228                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
 229                 if (found_key.objectid == location->objectid &&
 230                     btrfs_key_type(&found_key) == btrfs_key_type(location)) {
 231                         path->slots[0]--;
 232                         return 0;
 233                 }
 234         }
 235         return ret;
 236 }