btrfs-progs/extent-cache.c

329 lines
7.7 KiB
C
Raw Normal View History

/*
* Copyright (C) 2007 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 <stdio.h>
#include <stdlib.h>
#include "kerncompat.h"
#include "extent-cache.h"
#include "common/rbtree-utils.h"
struct cache_extent_search_range {
u64 objectid;
u64 start;
u64 size;
};
static int cache_tree_comp_range(struct rb_node *node, void *data)
{
struct cache_extent *entry;
struct cache_extent_search_range *range;
range = (struct cache_extent_search_range *)data;
entry = rb_entry(node, struct cache_extent, rb_node);
if (entry->start + entry->size <= range->start)
return 1;
else if (range->start + range->size <= entry->start)
return -1;
else
return 0;
}
static int cache_tree_comp_nodes(struct rb_node *node1, struct rb_node *node2)
{
struct cache_extent *entry;
struct cache_extent_search_range range;
entry = rb_entry(node2, struct cache_extent, rb_node);
range.start = entry->start;
range.size = entry->size;
return cache_tree_comp_range(node1, (void *)&range);
}
static int cache_tree_comp_range2(struct rb_node *node, void *data)
{
struct cache_extent *entry;
struct cache_extent_search_range *range;
range = (struct cache_extent_search_range *)data;
entry = rb_entry(node, struct cache_extent, rb_node);
if (entry->objectid < range->objectid)
return 1;
else if (entry->objectid > range->objectid)
return -1;
else if (entry->start + entry->size <= range->start)
return 1;
else if (range->start + range->size <= entry->start)
return -1;
else
return 0;
}
static int cache_tree_comp_nodes2(struct rb_node *node1, struct rb_node *node2)
{
struct cache_extent *entry;
struct cache_extent_search_range range;
entry = rb_entry(node2, struct cache_extent, rb_node);
range.objectid = entry->objectid;
range.start = entry->start;
range.size = entry->size;
return cache_tree_comp_range2(node1, (void *)&range);
}
void cache_tree_init(struct cache_tree *tree)
{
tree->root = RB_ROOT;
}
static struct cache_extent *alloc_cache_extent(u64 start, u64 size)
{
struct cache_extent *pe = malloc(sizeof(*pe));
if (!pe)
return pe;
pe->objectid = 0;
pe->start = start;
pe->size = size;
return pe;
}
int add_cache_extent(struct cache_tree *tree, u64 start, u64 size)
{
struct cache_extent *pe = alloc_cache_extent(start, size);
int ret;
if (!pe) {
fprintf(stderr, "memory allocation failed\n");
exit(1);
}
ret = insert_cache_extent(tree, pe);
if (ret)
free(pe);
return ret;
}
int insert_cache_extent(struct cache_tree *tree, struct cache_extent *pe)
{
return rb_insert(&tree->root, &pe->rb_node, cache_tree_comp_nodes);
}
int insert_cache_extent2(struct cache_tree *tree, struct cache_extent *pe)
{
return rb_insert(&tree->root, &pe->rb_node, cache_tree_comp_nodes2);
}
struct cache_extent *lookup_cache_extent(struct cache_tree *tree,
u64 start, u64 size)
{
struct rb_node *node;
struct cache_extent *entry;
struct cache_extent_search_range range;
range.start = start;
range.size = size;
node = rb_search(&tree->root, &range, cache_tree_comp_range, NULL);
if (!node)
return NULL;
entry = rb_entry(node, struct cache_extent, rb_node);
return entry;
}
struct cache_extent *lookup_cache_extent2(struct cache_tree *tree,
u64 objectid, u64 start, u64 size)
{
struct rb_node *node;
struct cache_extent *entry;
struct cache_extent_search_range range;
range.objectid = objectid;
range.start = start;
range.size = size;
node = rb_search(&tree->root, &range, cache_tree_comp_range2, NULL);
if (!node)
return NULL;
entry = rb_entry(node, struct cache_extent, rb_node);
return entry;
}
struct cache_extent *search_cache_extent(struct cache_tree *tree, u64 start)
{
struct rb_node *next;
struct rb_node *node;
struct cache_extent *entry;
struct cache_extent_search_range range;
range.start = start;
range.size = 1;
node = rb_search(&tree->root, &range, cache_tree_comp_range, &next);
if (!node)
node = next;
if (!node)
return NULL;
entry = rb_entry(node, struct cache_extent, rb_node);
return entry;
}
struct cache_extent *search_cache_extent2(struct cache_tree *tree,
u64 objectid, u64 start)
{
struct rb_node *next;
struct rb_node *node;
struct cache_extent *entry;
struct cache_extent_search_range range;
range.objectid = objectid;
range.start = start;
range.size = 1;
node = rb_search(&tree->root, &range, cache_tree_comp_range2, &next);
if (!node)
node = next;
if (!node)
return NULL;
entry = rb_entry(node, struct cache_extent, rb_node);
return entry;
}
struct cache_extent *first_cache_extent(struct cache_tree *tree)
{
struct rb_node *node = rb_first(&tree->root);
if (!node)
return NULL;
return rb_entry(node, struct cache_extent, rb_node);
}
struct cache_extent *last_cache_extent(struct cache_tree *tree)
{
struct rb_node *node = rb_last(&tree->root);
if (!node)
return NULL;
return rb_entry(node, struct cache_extent, rb_node);
}
struct cache_extent *prev_cache_extent(struct cache_extent *pe)
{
struct rb_node *node = rb_prev(&pe->rb_node);
if (!node)
return NULL;
return rb_entry(node, struct cache_extent, rb_node);
}
struct cache_extent *next_cache_extent(struct cache_extent *pe)
{
struct rb_node *node = rb_next(&pe->rb_node);
if (!node)
return NULL;
return rb_entry(node, struct cache_extent, rb_node);
}
void remove_cache_extent(struct cache_tree *tree, struct cache_extent *pe)
{
rb_erase(&pe->rb_node, &tree->root);
}
void cache_tree_free_extents(struct cache_tree *tree,
free_cache_extent free_func)
{
struct cache_extent *ce;
while ((ce = first_cache_extent(tree))) {
remove_cache_extent(tree, ce);
free_func(ce);
}
}
static void free_extent_cache(struct cache_extent *pe)
{
free(pe);
}
void free_extent_cache_tree(struct cache_tree *tree)
{
cache_tree_free_extents(tree, free_extent_cache);
}
int add_merge_cache_extent(struct cache_tree *tree, u64 start, u64 size)
{
struct cache_extent *cache;
struct cache_extent *next = NULL;
struct cache_extent *prev = NULL;
int next_merged = 0;
int prev_merged = 0;
int ret = 0;
if (cache_tree_empty(tree))
goto insert;
cache = search_cache_extent(tree, start);
if (!cache) {
/*
* Either the tree is completely empty, or the no range after
* start.
* Either way, the last cache_extent should be prev.
*/
prev = last_cache_extent(tree);
} else if (start <= cache->start) {
next = cache;
prev = prev_cache_extent(cache);
} else {
prev = cache;
next = next_cache_extent(cache);
}
/*
* Ensure the range to be inserted won't cover with existings
* Or we will need extra loop to do merge
*/
BUG_ON(next && start + size > next->start);
BUG_ON(prev && prev->start + prev->size > start);
if (next && start + size == next->start) {
next_merged = 1;
next->size = next->start + next->size - start;
next->start = start;
}
if (prev && prev->start + prev->size == start) {
prev_merged = 1;
if (next_merged) {
next->size = next->start + next->size - prev->start;
next->start = prev->start;
remove_cache_extent(tree, prev);
free(prev);
} else {
prev->size = start + size - prev->start;
}
}
insert:
if (!prev_merged && !next_merged)
ret = add_cache_extent(tree, start, size);
return ret;
}