fs/btrfs/ref-cache.h

   1 /*
   2  * Copyright (C) 2008 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 #ifndef __REFCACHE__
  19 #define __REFCACHE__
  20
  21 struct btrfs_extent_info {
  22         /* bytenr and num_bytes find the extent in the extent allocation tree */
  23         u64 bytenr;
  24         u64 num_bytes;
  25
  26         /* objectid and offset find the back reference for the file */
  27         u64 objectid;
  28         u64 offset;
  29 };
  30
  31 struct btrfs_leaf_ref {
  32         struct rb_node rb_node;
  33         struct btrfs_leaf_ref_tree *tree;
  34         int in_tree;
  35         atomic_t usage;
  36
  37         u64 root_gen;
  38         u64 bytenr;
  39         u64 owner;
  40         u64 generation;
  41         int nritems;
  42
  43         struct list_head list;
  44         struct btrfs_extent_info extents[];
  45 };
  46
  47 static inline size_t btrfs_leaf_ref_size(int nr_extents)
  48 {
  49         return sizeof(struct btrfs_leaf_ref) +
  50                sizeof(struct btrfs_extent_info) * nr_extents;
  51 }
  52
  53 static inline void btrfs_leaf_ref_tree_init(struct btrfs_leaf_ref_tree *tree)
  54 {
  55         tree->root.rb_node = NULL;
  56         INIT_LIST_HEAD(&tree->list);
  57         spin_lock_init(&tree->lock);
  58 }
  59
  60 static inline int btrfs_leaf_ref_tree_empty(struct btrfs_leaf_ref_tree *tree)
  61 {
  62         return RB_EMPTY_ROOT(&tree->root);
  63 }
  64
  65 void btrfs_leaf_ref_tree_init(struct btrfs_leaf_ref_tree *tree);
  66 struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(struct btrfs_root *root,
  67                                             int nr_extents);
  68 void btrfs_free_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref);
  69 struct btrfs_leaf_ref *btrfs_lookup_leaf_ref(struct btrfs_root *root,
  70                                              u64 bytenr);
  71 int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref,
  72                        int shared);
  73 int btrfs_remove_leaf_refs(struct btrfs_root *root, u64 max_root_gen,
  74                            int shared);
  75 int btrfs_remove_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref);
  76 #endif