3 #include <linux/slab.h>
4 #include <linux/module.h>
5 #include <linux/spinlock.h>
6 #include <linux/version.h>
7 #include <linux/hardirq.h>
8 #include "extent_map.h"
10 /* temporary define until extent_map moves out of btrfs */
11 struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
12 unsigned long extra_flags,
13 void (*ctor)(void *, struct kmem_cache *,
16 static struct kmem_cache *extent_map_cache;
18 int __init extent_map_init(void)
20 extent_map_cache = btrfs_cache_create("extent_map",
21 sizeof(struct extent_map), 0,
23 if (!extent_map_cache)
28 void extent_map_exit(void)
31 kmem_cache_destroy(extent_map_cache);
34 void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask)
36 tree->map.rb_node = NULL;
38 spin_lock_init(&tree->lock);
40 EXPORT_SYMBOL(extent_map_tree_init);
42 struct extent_map *alloc_extent_map(gfp_t mask)
44 struct extent_map *em;
45 em = kmem_cache_alloc(extent_map_cache, mask);
46 if (!em || IS_ERR(em))
50 atomic_set(&em->refs, 1);
53 EXPORT_SYMBOL(alloc_extent_map);
55 void free_extent_map(struct extent_map *em)
59 WARN_ON(atomic_read(&em->refs) == 0);
60 if (atomic_dec_and_test(&em->refs)) {
62 kmem_cache_free(extent_map_cache, em);
65 EXPORT_SYMBOL(free_extent_map);
67 static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
70 struct rb_node ** p = &root->rb_node;
71 struct rb_node * parent = NULL;
72 struct extent_map *entry;
76 entry = rb_entry(parent, struct extent_map, rb_node);
78 WARN_ON(!entry->in_tree);
80 if (offset < entry->start)
82 else if (offset >= extent_map_end(entry))
88 entry = rb_entry(node, struct extent_map, rb_node);
90 rb_link_node(node, parent, p);
91 rb_insert_color(node, root);
95 static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
96 struct rb_node **prev_ret,
97 struct rb_node **next_ret)
99 struct rb_node * n = root->rb_node;
100 struct rb_node *prev = NULL;
101 struct rb_node *orig_prev = NULL;
102 struct extent_map *entry;
103 struct extent_map *prev_entry = NULL;
106 entry = rb_entry(n, struct extent_map, rb_node);
110 WARN_ON(!entry->in_tree);
112 if (offset < entry->start)
114 else if (offset >= extent_map_end(entry))
122 while(prev && offset >= extent_map_end(prev_entry)) {
123 prev = rb_next(prev);
124 prev_entry = rb_entry(prev, struct extent_map, rb_node);
131 prev_entry = rb_entry(prev, struct extent_map, rb_node);
132 while(prev && offset < prev_entry->start) {
133 prev = rb_prev(prev);
134 prev_entry = rb_entry(prev, struct extent_map, rb_node);
141 static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
143 struct rb_node *prev;
145 ret = __tree_search(root, offset, &prev, NULL);
151 static int mergable_maps(struct extent_map *prev, struct extent_map *next)
153 if (extent_map_end(prev) == next->start &&
154 prev->flags == next->flags &&
155 prev->bdev == next->bdev &&
156 ((next->block_start == EXTENT_MAP_HOLE &&
157 prev->block_start == EXTENT_MAP_HOLE) ||
158 (next->block_start == EXTENT_MAP_INLINE &&
159 prev->block_start == EXTENT_MAP_INLINE) ||
160 (next->block_start == EXTENT_MAP_DELALLOC &&
161 prev->block_start == EXTENT_MAP_DELALLOC) ||
162 (next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
163 next->block_start == extent_map_block_end(prev)))) {
170 * add_extent_mapping tries a simple forward/backward merge with existing
171 * mappings. The extent_map struct passed in will be inserted into
172 * the tree directly (no copies made, just a reference taken).
174 int add_extent_mapping(struct extent_map_tree *tree,
175 struct extent_map *em)
178 struct extent_map *merge = NULL;
181 rb = tree_insert(&tree->map, em->start, &em->rb_node);
183 merge = rb_entry(rb, struct extent_map, rb_node);
187 atomic_inc(&em->refs);
188 if (em->start != 0) {
189 rb = rb_prev(&em->rb_node);
191 merge = rb_entry(rb, struct extent_map, rb_node);
192 if (rb && mergable_maps(merge, em)) {
193 em->start = merge->start;
194 em->len += merge->len;
195 em->block_start = merge->block_start;
197 rb_erase(&merge->rb_node, &tree->map);
198 free_extent_map(merge);
201 rb = rb_next(&em->rb_node);
203 merge = rb_entry(rb, struct extent_map, rb_node);
204 if (rb && mergable_maps(em, merge)) {
205 em->len += merge->len;
206 rb_erase(&merge->rb_node, &tree->map);
208 free_extent_map(merge);
214 EXPORT_SYMBOL(add_extent_mapping);
216 static u64 range_end(u64 start, u64 len)
218 if (start + len < start)
224 * lookup_extent_mapping returns the first extent_map struct in the
225 * tree that intersects the [start, len] range. There may
226 * be additional objects in the tree that intersect, so check the object
227 * returned carefully to make sure you don't need additional lookups.
229 struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
232 struct extent_map *em;
233 struct rb_node *rb_node;
234 struct rb_node *prev = NULL; struct rb_node *next = NULL; u64 end = range_end(start, len); em = tree->last; if (em && end > em->start && start < extent_map_end(em)) goto found;
236 rb_node = __tree_search(&tree->map, start, &prev, &next);
237 if (!rb_node && prev) {
238 em = rb_entry(prev, struct extent_map, rb_node);
239 if (end > em->start && start < extent_map_end(em))
242 if (!rb_node && next) {
243 em = rb_entry(next, struct extent_map, rb_node);
244 if (end > em->start && start < extent_map_end(em))
251 if (IS_ERR(rb_node)) {
252 em = ERR_PTR(PTR_ERR(rb_node));
255 em = rb_entry(rb_node, struct extent_map, rb_node);
256 if (end > em->start && start < extent_map_end(em))
263 atomic_inc(&em->refs);
268 EXPORT_SYMBOL(lookup_extent_mapping);
271 * removes an extent_map struct from the tree. No reference counts are
272 * dropped, and no checks are done to see if the range is in use
274 int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
278 rb_erase(&em->rb_node, &tree->map);
280 if (tree->last == em)
284 EXPORT_SYMBOL(remove_extent_mapping);