fs/btrfs/inode-map.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 int btrfs_find_highest_inode(struct btrfs_root *root, u64 *objectid)
  24 {
  25         struct btrfs_path *path;
  26         int ret;
  27         struct btrfs_leaf *l;
  28         struct btrfs_key search_key;
  29         int slot;
  30
  31         path = btrfs_alloc_path();
  32         BUG_ON(!path);
  33
  34         search_key.objectid = (u64)-1;
  35         search_key.offset = (u64)-1;
  36         ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
  37         if (ret < 0)
  38                 goto error;
  39         BUG_ON(ret == 0);
  40         if (path->slots[0] > 0) {
  41                 slot = path->slots[0] - 1;
  42                 l = btrfs_buffer_leaf(path->nodes[0]);
  43                 *objectid = btrfs_disk_key_objectid(&l->items[slot].key);
  44         } else {
  45                 *objectid = BTRFS_FIRST_FREE_OBJECTID;
  46         }
  47         ret = 0;
  48 error:
  49         btrfs_free_path(path);
  50         return ret;
  51 }
  52
  53 /*
  54  * walks the btree of allocated inodes and find a hole.
  55  */
  56 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
  57                              struct btrfs_root *root,
  58                              u64 dirid, u64 *objectid)
  59 {
  60         struct btrfs_path *path;
  61         struct btrfs_key key;
  62         int ret;
  63         u64 hole_size = 0;
  64         int slot = 0;
  65         u64 last_ino = 0;
  66         int start_found;
  67         struct btrfs_leaf *l;
  68         struct btrfs_key search_key;
  69         u64 search_start = dirid;
  70
  71         path = btrfs_alloc_path();
  72         BUG_ON(!path);
  73         search_key.flags = 0;
  74         search_start = root->last_inode_alloc;
  75         search_start = max(search_start, BTRFS_FIRST_FREE_OBJECTID);
  76         search_key.objectid = search_start;
  77         search_key.offset = 0;
  78
  79         btrfs_init_path(path);
  80         start_found = 0;
  81         ret = btrfs_search_slot(trans, root, &search_key, path, 0, 0);
  82         if (ret < 0)
  83                 goto error;
  84
  85         if (path->slots[0] > 0)
  86                 path->slots[0]--;
  87
  88         while (1) {
  89                 l = btrfs_buffer_leaf(path->nodes[0]);
  90                 slot = path->slots[0];
  91                 if (slot >= btrfs_header_nritems(&l->header)) {
  92                         ret = btrfs_next_leaf(root, path);
  93                         if (ret == 0)
  94                                 continue;
  95                         if (ret < 0)
  96                                 goto error;
  97                         if (!start_found) {
  98                                 *objectid = search_start;
  99                                 start_found = 1;
 100                                 goto found;
 101                         }
 102                         *objectid = last_ino > search_start ?
 103                                 last_ino : search_start;
 104                         goto found;
 105                 }
 106                 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
 107                 if (key.objectid >= search_start) {
 108                         if (start_found) {
 109                                 if (last_ino < search_start)
 110                                         last_ino = search_start;
 111                                 hole_size = key.objectid - last_ino;
 112                                 if (hole_size > 0) {
 113                                         *objectid = last_ino;
 114                                         goto found;
 115                                 }
 116                         }
 117                 }
 118                 start_found = 1;
 119                 last_ino = key.objectid + 1;
 120                 path->slots[0]++;
 121         }
 122         // FIXME -ENOSPC
 123 found:
 124         root->last_inode_alloc = *objectid;
 125         btrfs_release_path(root, path);
 126         btrfs_free_path(path);
 127         BUG_ON(*objectid < search_start);
 128         return 0;
 129 error:
 130         btrfs_release_path(root, path);
 131         btrfs_free_path(path);
 132         return ret;
 133 }