diff options
Diffstat (limited to 'fs/btrfs/ref-cache.c')
| -rw-r--r-- | fs/btrfs/ref-cache.c | 232 | 
1 files changed, 0 insertions, 232 deletions
diff --git a/fs/btrfs/ref-cache.c b/fs/btrfs/ref-cache.c deleted file mode 100644 index a97314cf6bd..00000000000 --- a/fs/btrfs/ref-cache.c +++ /dev/null @@ -1,232 +0,0 @@ -/* - * Copyright (C) 2008 Oracle.  All rights reserved. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License v2 as published by the Free Software Foundation. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this program; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 021110-1307, USA. - */ - -#include <linux/sched.h> -#include <linux/slab.h> -#include <linux/sort.h> -#include "ctree.h" -#include "ref-cache.h" -#include "transaction.h" - -/* - * leaf refs are used to cache the information about which extents - * a given leaf has references on.  This allows us to process that leaf - * in btrfs_drop_snapshot without needing to read it back from disk. - */ - -/* - * kmalloc a leaf reference struct and update the counters for the - * total ref cache size - */ -struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(struct btrfs_root *root, -					    int nr_extents) -{ -	struct btrfs_leaf_ref *ref; -	size_t size = btrfs_leaf_ref_size(nr_extents); - -	ref = kmalloc(size, GFP_NOFS); -	if (ref) { -		spin_lock(&root->fs_info->ref_cache_lock); -		root->fs_info->total_ref_cache_size += size; -		spin_unlock(&root->fs_info->ref_cache_lock); - -		memset(ref, 0, sizeof(*ref)); -		atomic_set(&ref->usage, 1); -		INIT_LIST_HEAD(&ref->list); -	} -	return ref; -} - -/* - * free a leaf reference struct and update the counters for the - * total ref cache size - */ -void btrfs_free_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref) -{ -	if (!ref) -		return; -	WARN_ON(atomic_read(&ref->usage) == 0); -	if (atomic_dec_and_test(&ref->usage)) { -		size_t size = btrfs_leaf_ref_size(ref->nritems); - -		BUG_ON(ref->in_tree); -		kfree(ref); - -		spin_lock(&root->fs_info->ref_cache_lock); -		root->fs_info->total_ref_cache_size -= size; -		spin_unlock(&root->fs_info->ref_cache_lock); -	} -} - -static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr, -				   struct rb_node *node) -{ -	struct rb_node **p = &root->rb_node; -	struct rb_node *parent = NULL; -	struct btrfs_leaf_ref *entry; - -	while (*p) { -		parent = *p; -		entry = rb_entry(parent, struct btrfs_leaf_ref, rb_node); - -		if (bytenr < entry->bytenr) -			p = &(*p)->rb_left; -		else if (bytenr > entry->bytenr) -			p = &(*p)->rb_right; -		else -			return parent; -	} - -	entry = rb_entry(node, struct btrfs_leaf_ref, rb_node); -	rb_link_node(node, parent, p); -	rb_insert_color(node, root); -	return NULL; -} - -static struct rb_node *tree_search(struct rb_root *root, u64 bytenr) -{ -	struct rb_node *n = root->rb_node; -	struct btrfs_leaf_ref *entry; - -	while (n) { -		entry = rb_entry(n, struct btrfs_leaf_ref, rb_node); -		WARN_ON(!entry->in_tree); - -		if (bytenr < entry->bytenr) -			n = n->rb_left; -		else if (bytenr > entry->bytenr) -			n = n->rb_right; -		else -			return n; -	} -	return NULL; -} - -int btrfs_remove_leaf_refs(struct btrfs_root *root, u64 max_root_gen, -			   int shared) -{ -	struct btrfs_leaf_ref *ref = NULL; -	struct btrfs_leaf_ref_tree *tree = root->ref_tree; - -	if (shared) -		tree = &root->fs_info->shared_ref_tree; -	if (!tree) -		return 0; - -	spin_lock(&tree->lock); -	while (!list_empty(&tree->list)) { -		ref = list_entry(tree->list.next, struct btrfs_leaf_ref, list); -		BUG_ON(ref->tree != tree); -		if (ref->root_gen > max_root_gen) -			break; -		if (!xchg(&ref->in_tree, 0)) { -			cond_resched_lock(&tree->lock); -			continue; -		} - -		rb_erase(&ref->rb_node, &tree->root); -		list_del_init(&ref->list); - -		spin_unlock(&tree->lock); -		btrfs_free_leaf_ref(root, ref); -		cond_resched(); -		spin_lock(&tree->lock); -	} -	spin_unlock(&tree->lock); -	return 0; -} - -/* - * find the leaf ref for a given extent.  This returns the ref struct with - * a usage reference incremented - */ -struct btrfs_leaf_ref *btrfs_lookup_leaf_ref(struct btrfs_root *root, -					     u64 bytenr) -{ -	struct rb_node *rb; -	struct btrfs_leaf_ref *ref = NULL; -	struct btrfs_leaf_ref_tree *tree = root->ref_tree; -again: -	if (tree) { -		spin_lock(&tree->lock); -		rb = tree_search(&tree->root, bytenr); -		if (rb) -			ref = rb_entry(rb, struct btrfs_leaf_ref, rb_node); -		if (ref) -			atomic_inc(&ref->usage); -		spin_unlock(&tree->lock); -		if (ref) -			return ref; -	} -	if (tree != &root->fs_info->shared_ref_tree) { -		tree = &root->fs_info->shared_ref_tree; -		goto again; -	} -	return NULL; -} - -/* - * add a fully filled in leaf ref struct - * remove all the refs older than a given root generation - */ -int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref, -		       int shared) -{ -	int ret = 0; -	struct rb_node *rb; -	struct btrfs_leaf_ref_tree *tree = root->ref_tree; - -	if (shared) -		tree = &root->fs_info->shared_ref_tree; - -	spin_lock(&tree->lock); -	rb = tree_insert(&tree->root, ref->bytenr, &ref->rb_node); -	if (rb) { -		ret = -EEXIST; -	} else { -		atomic_inc(&ref->usage); -		ref->tree = tree; -		ref->in_tree = 1; -		list_add_tail(&ref->list, &tree->list); -	} -	spin_unlock(&tree->lock); -	return ret; -} - -/* - * remove a single leaf ref from the tree.  This drops the ref held by the tree - * only - */ -int btrfs_remove_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref) -{ -	struct btrfs_leaf_ref_tree *tree; - -	if (!xchg(&ref->in_tree, 0)) -		return 0; - -	tree = ref->tree; -	spin_lock(&tree->lock); - -	rb_erase(&ref->rb_node, &tree->root); -	list_del_init(&ref->list); - -	spin_unlock(&tree->lock); - -	btrfs_free_leaf_ref(root, ref); -	return 0; -}  | 
