e465768938
Btrfs has a cache of reference counts in leaves, allowing it to avoid reading tree leaves while deleting snapshots. To reduce contention with multiple subvolumes, this cache is private to each subvolume. This patch adds shared reference cache support. The new space balancing code plays with multiple subvols at the same time, So the old per-subvol reference cache is not well suited. Signed-off-by: Chris Mason <chris.mason@oracle.com>
75 lines
2.1 KiB
C
75 lines
2.1 KiB
C
/*
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* Copyright (C) 2008 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef __REFCACHE__
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#define __REFCACHE__
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struct btrfs_extent_info {
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u64 bytenr;
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u64 num_bytes;
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u64 objectid;
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u64 offset;
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};
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struct btrfs_leaf_ref {
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struct rb_node rb_node;
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struct btrfs_leaf_ref_tree *tree;
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int in_tree;
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atomic_t usage;
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u64 root_gen;
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u64 bytenr;
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u64 owner;
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u64 generation;
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int nritems;
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struct list_head list;
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struct btrfs_extent_info extents[];
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};
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static inline size_t btrfs_leaf_ref_size(int nr_extents)
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{
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return sizeof(struct btrfs_leaf_ref) +
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sizeof(struct btrfs_extent_info) * nr_extents;
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}
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static inline void btrfs_leaf_ref_tree_init(struct btrfs_leaf_ref_tree *tree)
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{
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tree->root.rb_node = NULL;
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INIT_LIST_HEAD(&tree->list);
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spin_lock_init(&tree->lock);
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}
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static inline int btrfs_leaf_ref_tree_empty(struct btrfs_leaf_ref_tree *tree)
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{
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return RB_EMPTY_ROOT(&tree->root);
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}
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void btrfs_leaf_ref_tree_init(struct btrfs_leaf_ref_tree *tree);
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struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(struct btrfs_root *root,
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int nr_extents);
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void btrfs_free_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref);
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struct btrfs_leaf_ref *btrfs_lookup_leaf_ref(struct btrfs_root *root,
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u64 bytenr);
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int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref,
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int shared);
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int btrfs_remove_leaf_refs(struct btrfs_root *root, u64 max_root_gen,
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int shared);
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int btrfs_remove_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref);
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#endif
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