This patch implements an infrastructure to insert/search/merge an extent range (with variable length).
This provides the basis for later extent buffer cache used in btrfs.
Signed-off-by: Qu Wenruo wqu@suse.com --- fs/btrfs/extent-cache.c | 318 ++++++++++++++++++++++++++++++++++++++++ fs/btrfs/extent-cache.h | 104 +++++++++++++ 2 files changed, 422 insertions(+) create mode 100644 fs/btrfs/extent-cache.c create mode 100644 fs/btrfs/extent-cache.h
diff --git a/fs/btrfs/extent-cache.c b/fs/btrfs/extent-cache.c new file mode 100644 index 000000000000..e7b055f55422 --- /dev/null +++ b/fs/btrfs/extent-cache.c @@ -0,0 +1,318 @@ +// SPDX-License-Identifier: GPL-2.0+ + +/* + * Cross-ported from the same named file of btrfs-progs. + * + * Minor modification to include headers. + */ +#include <linux/kernel.h> +#include <linux/rbtree.h> +#include <linux/errno.h> +#include <linux/bug.h> +#include <stdlib.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) + return -ENOMEM; + + 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; +} diff --git a/fs/btrfs/extent-cache.h b/fs/btrfs/extent-cache.h new file mode 100644 index 000000000000..b6acd09fe983 --- /dev/null +++ b/fs/btrfs/extent-cache.h @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0+ + +/* + * Cross-ported from the same named file of btrfs-progs. + * + * Minor modification to include headers. + */ +#ifndef __BTRFS_EXTENT_CACHE_H__ +#define __BTRFS_EXTENT_CACHE_H__ + +#include <linux/rbtree.h> +#include <linux/types.h> + +struct cache_tree { + struct rb_root root; +}; + +struct cache_extent { + struct rb_node rb_node; + u64 objectid; + u64 start; + u64 size; +}; + +void cache_tree_init(struct cache_tree *tree); + +struct cache_extent *first_cache_extent(struct cache_tree *tree); +struct cache_extent *last_cache_extent(struct cache_tree *tree); +struct cache_extent *prev_cache_extent(struct cache_extent *pe); +struct cache_extent *next_cache_extent(struct cache_extent *pe); + +/* + * Find a cache_extent which covers start. + * + * If not found, return next cache_extent if possible. + */ +struct cache_extent *search_cache_extent(struct cache_tree *tree, u64 start); + +/* + * Find a cache_extent which restrictly covers start. + * + * If not found, return NULL. + */ +struct cache_extent *lookup_cache_extent(struct cache_tree *tree, + u64 start, u64 size); + +/* + * Add an non-overlap extent into cache tree + * + * If [start, start+size) overlap with existing one, it will return -EEXIST. + */ +int add_cache_extent(struct cache_tree *tree, u64 start, u64 size); + +/* + * Same with add_cache_extent, but with cache_extent strcut. + */ +int insert_cache_extent(struct cache_tree *tree, struct cache_extent *pe); +void remove_cache_extent(struct cache_tree *tree, struct cache_extent *pe); + +static inline int cache_tree_empty(struct cache_tree *tree) +{ + return RB_EMPTY_ROOT(&tree->root); +} + +typedef void (*free_cache_extent)(struct cache_extent *pe); + +void cache_tree_free_extents(struct cache_tree *tree, + free_cache_extent free_func); + +#define FREE_EXTENT_CACHE_BASED_TREE(name, free_func) \ +static void free_##name##_tree(struct cache_tree *tree) \ +{ \ + cache_tree_free_extents(tree, free_func); \ +} + +void free_extent_cache_tree(struct cache_tree *tree); + +/* + * Search a cache_extent with same objectid, and covers start. + * + * If not found, return next if possible. + */ +struct cache_extent *search_cache_extent2(struct cache_tree *tree, + u64 objectid, u64 start); +/* + * Search a cache_extent with same objectid, and covers the range + * [start, start + size) + * + * If not found, return next cache_extent if possible. + */ +struct cache_extent *lookup_cache_extent2(struct cache_tree *tree, + u64 objectid, u64 start, u64 size); +int insert_cache_extent2(struct cache_tree *tree, struct cache_extent *pe); + +/* + * Insert a cache_extent range [start, start + size). + * + * This function may merge with existing cache_extent. + * NOTE: caller must ensure the inserted range won't cover with any existing + * range. + */ +int add_merge_cache_extent(struct cache_tree *tree, u64 start, u64 size); + +#endif