root-tree.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 "transaction.h"
  21 #include "disk-io.h"
  22 #include "print-tree.h"
  23
  24 int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
  25                         struct btrfs_root_item *item, struct btrfs_key *key)
  26 {
  27         struct btrfs_path *path;
  28         struct btrfs_key search_key;
  29         struct btrfs_key found_key;
  30         struct extent_buffer *l;
  31         int ret;
  32         int slot;
  33
  34         search_key.objectid = objectid;
  35         search_key.type = BTRFS_ROOT_ITEM_KEY;
  36         search_key.offset = (u64)-1;
  37
  38         path = btrfs_alloc_path();
  39         BUG_ON(!path);
  40         ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
  41         if (ret < 0)
  42                 goto out;
  43
  44         BUG_ON(ret == 0);
  45         l = path->nodes[0];
  46         BUG_ON(path->slots[0] == 0);
  47         slot = path->slots[0] - 1;
  48         btrfs_item_key_to_cpu(l, &found_key, slot);
  49         if (found_key.objectid != objectid) {
  50                 ret = 1;
  51                 goto out;
  52         }
  53         read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
  54                            sizeof(*item));
  55         memcpy(key, &found_key, sizeof(found_key));
  56         ret = 0;
  57 out:
  58         btrfs_release_path(root, path);
  59         btrfs_free_path(path);
  60         return ret;
  61 }
  62
  63 int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
  64                       *root, struct btrfs_key *key, struct btrfs_root_item
  65                       *item)
  66 {
  67         struct btrfs_path *path;
  68         struct extent_buffer *l;
  69         int ret;
  70         int slot;
  71         unsigned long ptr;
  72
  73         path = btrfs_alloc_path();
  74         BUG_ON(!path);
  75         ret = btrfs_search_slot(trans, root, key, path, 0, 1);
  76         if (ret < 0)
  77                 goto out;
  78         BUG_ON(ret != 0);
  79         l = path->nodes[0];
  80         slot = path->slots[0];
  81         ptr = btrfs_item_ptr_offset(l, slot);
  82         write_extent_buffer(l, item, ptr, sizeof(*item));
  83         btrfs_mark_buffer_dirty(path->nodes[0]);
  84 out:
  85         btrfs_release_path(root, path);
  86         btrfs_free_path(path);
  87         return ret;
  88 }
  89
  90 int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
  91                       *root, struct btrfs_key *key, struct btrfs_root_item
  92                       *item)
  93 {
  94         int ret;
  95         ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
  96         return ret;
  97 }
  98
  99 #if 0
 100 int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid,
 101                           struct btrfs_root *latest)
 102 {
 103         struct btrfs_root *dead_root;
 104         struct btrfs_item *item;
 105         struct btrfs_root_item *ri;
 106         struct btrfs_key key;
 107         struct btrfs_path *path;
 108         int ret;
 109         u32 nritems;
 110         struct extent_buffer *leaf;
 111         int slot;
 112
 113         key.objectid = objectid;
 114         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 115         key.offset = 0;
 116         path = btrfs_alloc_path();
 117         if (!path)
 118                 return -ENOMEM;
 119         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 120         if (ret < 0)
 121                 goto err;
 122         while(1) {
 123                 leaf = path->nodes[0];
 124                 nritems = btrfs_header_nritems(leaf);
 125                 slot = path->slots[0];
 126                 if (slot >= nritems) {
 127                         ret = btrfs_next_leaf(root, path);
 128                         if (ret)
 129                                 break;
 130                         leaf = path->nodes[0];
 131                         nritems = btrfs_header_nritems(leaf);
 132                         slot = path->slots[0];
 133                 }
 134                 item = btrfs_item_nr(leaf, slot);
 135                 btrfs_item_key_to_cpu(leaf, &key, slot);
 136                 if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
 137                         goto next;
 138
 139                 if (key.objectid < objectid)
 140                         goto next;
 141
 142                 if (key.objectid > objectid)
 143                         break;
 144
 145                 ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
 146                 if (btrfs_disk_root_refs(leaf, ri) != 0)
 147                         goto next;
 148
 149                 dead_root = btrfs_read_fs_root_no_radix(root->fs_info, &key);
 150                 if (IS_ERR(dead_root)) {
 151                         ret = PTR_ERR(dead_root);
 152                         goto err;
 153                 }
 154
 155                 ret = btrfs_add_dead_root(dead_root, latest,
 156                                           &root->fs_info->dead_roots);
 157                 if (ret)
 158                         goto err;
 159 next:
 160                 slot++;
 161                 path->slots[0]++;
 162         }
 163         ret = 0;
 164 err:
 165         btrfs_free_path(path);
 166         return ret;
 167 }
 168 #endif
 169
 170 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 171                    struct btrfs_key *key)
 172 {
 173         struct btrfs_path *path;
 174         int ret;
 175         u32 refs;
 176         struct btrfs_root_item *ri;
 177         struct extent_buffer *leaf;
 178
 179         path = btrfs_alloc_path();
 180         BUG_ON(!path);
 181         ret = btrfs_search_slot(trans, root, key, path, -1, 1);
 182         if (ret < 0)
 183                 goto out;
 184         if (ret) {
 185 btrfs_print_leaf(root, path->nodes[0]);
 186 printk("failed to del %llu %u %llu\n",
 187         (unsigned long long)key->objectid,
 188         key->type,
 189         (unsigned long long)key->offset);
 190
 191         }
 192         BUG_ON(ret != 0);
 193         leaf = path->nodes[0];
 194         ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
 195
 196         refs = btrfs_disk_root_refs(leaf, ri);
 197         BUG_ON(refs != 0);
 198         ret = btrfs_del_item(trans, root, path);
 199 out:
 200         btrfs_release_path(root, path);
 201         btrfs_free_path(path);
 202         return ret;
 203 }
 204
 205 /*
 206  * add a btrfs_root_ref item.  type is either BTRFS_ROOT_REF_KEY
 207  * or BTRFS_ROOT_BACKREF_KEY.
 208  *
 209  * The dirid, sequence, name and name_len refer to the directory entry
 210  * that is referencing the root.
 211  *
 212  * For a forward ref, the root_id is the id of the tree referencing
 213  * the root and ref_id is the id of the subvol  or snapshot.
 214  *
 215  * For a back ref the root_id is the id of the subvol or snapshot and
 216  * ref_id is the id of the tree referencing it.
 217  */
 218 int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
 219                        struct btrfs_root *tree_root,
 220                        u64 root_id, u8 type, u64 ref_id,
 221                        u64 dirid, u64 sequence,
 222                        const char *name, int name_len)
 223 {
 224         struct btrfs_key key;
 225         int ret;
 226         struct btrfs_path *path;
 227         struct btrfs_root_ref *ref;
 228         struct extent_buffer *leaf;
 229         unsigned long ptr;
 230
 231
 232         path = btrfs_alloc_path();
 233
 234         key.objectid = root_id;
 235         key.type = type;
 236         key.offset = ref_id;
 237
 238         ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
 239                                       sizeof(*ref) + name_len);
 240         BUG_ON(ret);
 241
 242         leaf = path->nodes[0];
 243         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
 244         btrfs_set_root_ref_dirid(leaf, ref, dirid);
 245         btrfs_set_root_ref_sequence(leaf, ref, sequence);
 246         btrfs_set_root_ref_name_len(leaf, ref, name_len);
 247         ptr = (unsigned long)(ref + 1);
 248         write_extent_buffer(leaf, name, ptr, name_len);
 249         btrfs_mark_buffer_dirty(leaf);
 250
 251         btrfs_free_path(path);
 252         return ret;
 253 }