blob: 7c97b330145981d241cec9f13a75b3fa1869f8db [file] [log] [blame]
Chris Masond1310b22008-01-24 16:13:08 -05001#include <linux/err.h>
Chris Masond1310b22008-01-24 16:13:08 -05002#include <linux/slab.h>
Chris Masona52d9a82007-08-27 16:49:44 -04003#include <linux/module.h>
4#include <linux/spinlock.h>
Chris Masond1310b22008-01-24 16:13:08 -05005#include <linux/hardirq.h>
Li Zefan261507a02010-12-17 14:21:50 +08006#include "ctree.h"
Chris Masona52d9a82007-08-27 16:49:44 -04007#include "extent_map.h"
8
Chris Mason86479a02007-09-10 19:58:16 -04009
Chris Masona52d9a82007-08-27 16:49:44 -040010static struct kmem_cache *extent_map_cache;
Chris Masonca664622007-11-27 11:16:35 -050011
Wyatt Banks2f4cbe62007-11-19 10:22:33 -050012int __init extent_map_init(void)
Chris Masona52d9a82007-08-27 16:49:44 -040013{
Christoph Hellwig9601e3f2009-04-13 15:33:09 +020014 extent_map_cache = kmem_cache_create("extent_map",
15 sizeof(struct extent_map), 0,
16 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
Wyatt Banks2f4cbe62007-11-19 10:22:33 -050017 if (!extent_map_cache)
18 return -ENOMEM;
Wyatt Banks2f4cbe62007-11-19 10:22:33 -050019 return 0;
Chris Masona52d9a82007-08-27 16:49:44 -040020}
21
Christian Hesse17636e02007-12-11 09:25:06 -050022void extent_map_exit(void)
Chris Masona52d9a82007-08-27 16:49:44 -040023{
Chris Masona52d9a82007-08-27 16:49:44 -040024 if (extent_map_cache)
25 kmem_cache_destroy(extent_map_cache);
Chris Masona52d9a82007-08-27 16:49:44 -040026}
27
Christoph Hellwig9d2423c2008-06-11 21:52:17 -040028/**
29 * extent_map_tree_init - initialize extent map tree
30 * @tree: tree to initialize
Christoph Hellwig9d2423c2008-06-11 21:52:17 -040031 *
32 * Initialize the extent tree @tree. Should be called for each new inode
33 * or other user of the extent_map interface.
34 */
David Sterbaa8067e02011-04-21 00:34:43 +020035void extent_map_tree_init(struct extent_map_tree *tree)
Chris Masona52d9a82007-08-27 16:49:44 -040036{
Eric Paris6bef4d32010-02-23 19:43:04 +000037 tree->map = RB_ROOT;
Chris Mason890871b2009-09-02 16:24:52 -040038 rwlock_init(&tree->lock);
Chris Masona52d9a82007-08-27 16:49:44 -040039}
Chris Masona52d9a82007-08-27 16:49:44 -040040
Christoph Hellwig9d2423c2008-06-11 21:52:17 -040041/**
42 * alloc_extent_map - allocate new extent map structure
Christoph Hellwig9d2423c2008-06-11 21:52:17 -040043 *
44 * Allocate a new extent_map structure. The new structure is
45 * returned with a reference count of one and needs to be
46 * freed using free_extent_map()
47 */
David Sterba172ddd62011-04-21 00:48:27 +020048struct extent_map *alloc_extent_map(void)
Chris Masona52d9a82007-08-27 16:49:44 -040049{
50 struct extent_map *em;
David Sterba172ddd62011-04-21 00:48:27 +020051 em = kmem_cache_alloc(extent_map_cache, GFP_NOFS);
Tsutomu Itohc26a9202011-02-14 00:45:29 +000052 if (!em)
53 return NULL;
Chris Masona52d9a82007-08-27 16:49:44 -040054 em->in_tree = 0;
Chris Masond1310b22008-01-24 16:13:08 -050055 em->flags = 0;
Li Zefan261507a02010-12-17 14:21:50 +080056 em->compress_type = BTRFS_COMPRESS_NONE;
Chris Masona52d9a82007-08-27 16:49:44 -040057 atomic_set(&em->refs, 1);
58 return em;
59}
Chris Masona52d9a82007-08-27 16:49:44 -040060
Christoph Hellwig9d2423c2008-06-11 21:52:17 -040061/**
62 * free_extent_map - drop reference count of an extent_map
63 * @em: extent map beeing releasead
64 *
65 * Drops the reference out on @em by one and free the structure
66 * if the reference count hits zero.
67 */
Chris Masona52d9a82007-08-27 16:49:44 -040068void free_extent_map(struct extent_map *em)
69{
Chris Mason2bf5a722007-08-30 11:54:02 -040070 if (!em)
71 return;
Chris Masond1310b22008-01-24 16:13:08 -050072 WARN_ON(atomic_read(&em->refs) == 0);
Chris Masona52d9a82007-08-27 16:49:44 -040073 if (atomic_dec_and_test(&em->refs)) {
74 WARN_ON(em->in_tree);
75 kmem_cache_free(extent_map_cache, em);
76 }
77}
Chris Masona52d9a82007-08-27 16:49:44 -040078
Chris Masona52d9a82007-08-27 16:49:44 -040079static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
80 struct rb_node *node)
81{
Chris Masond3977122009-01-05 21:25:51 -050082 struct rb_node **p = &root->rb_node;
83 struct rb_node *parent = NULL;
Chris Masond1310b22008-01-24 16:13:08 -050084 struct extent_map *entry;
Chris Masona52d9a82007-08-27 16:49:44 -040085
Chris Masond3977122009-01-05 21:25:51 -050086 while (*p) {
Chris Masona52d9a82007-08-27 16:49:44 -040087 parent = *p;
Chris Masond1310b22008-01-24 16:13:08 -050088 entry = rb_entry(parent, struct extent_map, rb_node);
89
90 WARN_ON(!entry->in_tree);
Chris Masona52d9a82007-08-27 16:49:44 -040091
92 if (offset < entry->start)
93 p = &(*p)->rb_left;
Chris Masond1310b22008-01-24 16:13:08 -050094 else if (offset >= extent_map_end(entry))
Chris Masona52d9a82007-08-27 16:49:44 -040095 p = &(*p)->rb_right;
96 else
97 return parent;
98 }
99
Chris Masond1310b22008-01-24 16:13:08 -0500100 entry = rb_entry(node, struct extent_map, rb_node);
Chris Masona52d9a82007-08-27 16:49:44 -0400101 entry->in_tree = 1;
102 rb_link_node(node, parent, p);
103 rb_insert_color(node, root);
104 return NULL;
105}
106
Chris Masond352ac62008-09-29 15:18:18 -0400107/*
108 * search through the tree for an extent_map with a given offset. If
109 * it can't be found, try to find some neighboring extents
110 */
Chris Masona52d9a82007-08-27 16:49:44 -0400111static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
Chris Mason5f564062008-01-22 16:47:59 -0500112 struct rb_node **prev_ret,
113 struct rb_node **next_ret)
Chris Masona52d9a82007-08-27 16:49:44 -0400114{
Chris Masond3977122009-01-05 21:25:51 -0500115 struct rb_node *n = root->rb_node;
Chris Masona52d9a82007-08-27 16:49:44 -0400116 struct rb_node *prev = NULL;
Chris Mason5f564062008-01-22 16:47:59 -0500117 struct rb_node *orig_prev = NULL;
Chris Masond1310b22008-01-24 16:13:08 -0500118 struct extent_map *entry;
119 struct extent_map *prev_entry = NULL;
Chris Masona52d9a82007-08-27 16:49:44 -0400120
Chris Masond3977122009-01-05 21:25:51 -0500121 while (n) {
Chris Masond1310b22008-01-24 16:13:08 -0500122 entry = rb_entry(n, struct extent_map, rb_node);
Chris Masona52d9a82007-08-27 16:49:44 -0400123 prev = n;
124 prev_entry = entry;
125
Chris Masond1310b22008-01-24 16:13:08 -0500126 WARN_ON(!entry->in_tree);
127
Chris Masona52d9a82007-08-27 16:49:44 -0400128 if (offset < entry->start)
129 n = n->rb_left;
Chris Masond1310b22008-01-24 16:13:08 -0500130 else if (offset >= extent_map_end(entry))
Chris Masona52d9a82007-08-27 16:49:44 -0400131 n = n->rb_right;
132 else
133 return n;
134 }
Chris Mason5f564062008-01-22 16:47:59 -0500135
136 if (prev_ret) {
137 orig_prev = prev;
Chris Masond3977122009-01-05 21:25:51 -0500138 while (prev && offset >= extent_map_end(prev_entry)) {
Chris Mason5f564062008-01-22 16:47:59 -0500139 prev = rb_next(prev);
Chris Masond1310b22008-01-24 16:13:08 -0500140 prev_entry = rb_entry(prev, struct extent_map, rb_node);
Chris Mason5f564062008-01-22 16:47:59 -0500141 }
142 *prev_ret = prev;
143 prev = orig_prev;
Chris Masona52d9a82007-08-27 16:49:44 -0400144 }
Chris Mason5f564062008-01-22 16:47:59 -0500145
146 if (next_ret) {
Chris Masond1310b22008-01-24 16:13:08 -0500147 prev_entry = rb_entry(prev, struct extent_map, rb_node);
Chris Masond3977122009-01-05 21:25:51 -0500148 while (prev && offset < prev_entry->start) {
Chris Mason5f564062008-01-22 16:47:59 -0500149 prev = rb_prev(prev);
Chris Masond1310b22008-01-24 16:13:08 -0500150 prev_entry = rb_entry(prev, struct extent_map, rb_node);
Chris Mason5f564062008-01-22 16:47:59 -0500151 }
152 *next_ret = prev;
153 }
Chris Masona52d9a82007-08-27 16:49:44 -0400154 return NULL;
155}
156
Chris Masond352ac62008-09-29 15:18:18 -0400157/* check to see if two extent_map structs are adjacent and safe to merge */
Chris Masond1310b22008-01-24 16:13:08 -0500158static int mergable_maps(struct extent_map *prev, struct extent_map *next)
Chris Masona52d9a82007-08-27 16:49:44 -0400159{
Chris Mason7f3c74f2008-07-18 12:01:11 -0400160 if (test_bit(EXTENT_FLAG_PINNED, &prev->flags))
161 return 0;
162
Chris Masonc8b97812008-10-29 14:49:59 -0400163 /*
164 * don't merge compressed extents, we need to know their
165 * actual size
166 */
167 if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags))
168 return 0;
169
Chris Masond1310b22008-01-24 16:13:08 -0500170 if (extent_map_end(prev) == next->start &&
171 prev->flags == next->flags &&
172 prev->bdev == next->bdev &&
173 ((next->block_start == EXTENT_MAP_HOLE &&
174 prev->block_start == EXTENT_MAP_HOLE) ||
175 (next->block_start == EXTENT_MAP_INLINE &&
176 prev->block_start == EXTENT_MAP_INLINE) ||
177 (next->block_start == EXTENT_MAP_DELALLOC &&
178 prev->block_start == EXTENT_MAP_DELALLOC) ||
179 (next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
180 next->block_start == extent_map_block_end(prev)))) {
181 return 1;
182 }
Chris Masona52d9a82007-08-27 16:49:44 -0400183 return 0;
184}
185
Li Zefan4d2c8f622011-07-14 03:18:33 +0000186static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
Chris Masona1ed8352009-09-11 12:27:37 -0400187{
Chris Masona1ed8352009-09-11 12:27:37 -0400188 struct extent_map *merge = NULL;
189 struct rb_node *rb;
Chris Masona1ed8352009-09-11 12:27:37 -0400190
191 if (em->start != 0) {
192 rb = rb_prev(&em->rb_node);
193 if (rb)
194 merge = rb_entry(rb, struct extent_map, rb_node);
195 if (rb && mergable_maps(merge, em)) {
196 em->start = merge->start;
197 em->len += merge->len;
198 em->block_len += merge->block_len;
199 em->block_start = merge->block_start;
200 merge->in_tree = 0;
201 rb_erase(&merge->rb_node, &tree->map);
202 free_extent_map(merge);
203 }
204 }
205
206 rb = rb_next(&em->rb_node);
207 if (rb)
208 merge = rb_entry(rb, struct extent_map, rb_node);
209 if (rb && mergable_maps(em, merge)) {
210 em->len += merge->len;
211 em->block_len += merge->len;
212 rb_erase(&merge->rb_node, &tree->map);
213 merge->in_tree = 0;
214 free_extent_map(merge);
215 }
Li Zefan4d2c8f622011-07-14 03:18:33 +0000216}
217
218int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)
219{
220 int ret = 0;
221 struct extent_map *em;
222
223 write_lock(&tree->lock);
224 em = lookup_extent_mapping(tree, start, len);
225
226 WARN_ON(!em || em->start != start);
227
228 if (!em)
229 goto out;
230
231 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
232
233 try_merge_map(tree, em);
Chris Masona1ed8352009-09-11 12:27:37 -0400234
235 free_extent_map(em);
236out:
237 write_unlock(&tree->lock);
238 return ret;
239
240}
241
Christoph Hellwig9d2423c2008-06-11 21:52:17 -0400242/**
243 * add_extent_mapping - add new extent map to the extent tree
244 * @tree: tree to insert new map in
245 * @em: map to insert
246 *
247 * Insert @em into @tree or perform a simple forward/backward merge with
248 * existing mappings. The extent_map struct passed in will be inserted
249 * into the tree directly, with an additional reference taken, or a
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300250 * reference dropped if the merge attempt was successful.
Chris Masona52d9a82007-08-27 16:49:44 -0400251 */
252int add_extent_mapping(struct extent_map_tree *tree,
253 struct extent_map *em)
254{
255 int ret = 0;
Chris Masona52d9a82007-08-27 16:49:44 -0400256 struct rb_node *rb;
Chris Mason7c2fe322008-08-20 08:51:50 -0400257 struct extent_map *exist;
Chris Masona52d9a82007-08-27 16:49:44 -0400258
Chris Mason7c2fe322008-08-20 08:51:50 -0400259 exist = lookup_extent_mapping(tree, em->start, em->len);
260 if (exist) {
261 free_extent_map(exist);
262 ret = -EEXIST;
263 goto out;
264 }
Chris Masond1310b22008-01-24 16:13:08 -0500265 rb = tree_insert(&tree->map, em->start, &em->rb_node);
Chris Masona52d9a82007-08-27 16:49:44 -0400266 if (rb) {
Chris Masona52d9a82007-08-27 16:49:44 -0400267 ret = -EEXIST;
268 goto out;
269 }
270 atomic_inc(&em->refs);
Li Zefan4d2c8f622011-07-14 03:18:33 +0000271
272 try_merge_map(tree, em);
Chris Masona52d9a82007-08-27 16:49:44 -0400273out:
Chris Masona52d9a82007-08-27 16:49:44 -0400274 return ret;
275}
Chris Masona52d9a82007-08-27 16:49:44 -0400276
Chris Masond352ac62008-09-29 15:18:18 -0400277/* simple helper to do math around the end of an extent, handling wrap */
Chris Masond1310b22008-01-24 16:13:08 -0500278static u64 range_end(u64 start, u64 len)
279{
280 if (start + len < start)
281 return (u64)-1;
282 return start + len;
283}
284
Li Zefaned64f062011-07-14 03:18:15 +0000285struct extent_map *__lookup_extent_mapping(struct extent_map_tree *tree,
286 u64 start, u64 len, int strict)
287{
288 struct extent_map *em;
289 struct rb_node *rb_node;
290 struct rb_node *prev = NULL;
291 struct rb_node *next = NULL;
292 u64 end = range_end(start, len);
293
294 rb_node = __tree_search(&tree->map, start, &prev, &next);
295 if (!rb_node) {
296 if (prev)
297 rb_node = prev;
298 else if (next)
299 rb_node = next;
300 else
301 return NULL;
302 }
303
304 em = rb_entry(rb_node, struct extent_map, rb_node);
305
306 if (strict && !(end > em->start && start < extent_map_end(em)))
307 return NULL;
308
309 atomic_inc(&em->refs);
310 return em;
311}
312
Christoph Hellwig9d2423c2008-06-11 21:52:17 -0400313/**
314 * lookup_extent_mapping - lookup extent_map
315 * @tree: tree to lookup in
316 * @start: byte offset to start the search
317 * @len: length of the lookup range
318 *
319 * Find and return the first extent_map struct in @tree that intersects the
320 * [start, len] range. There may be additional objects in the tree that
321 * intersect, so check the object returned carefully to make sure that no
322 * additional lookups are needed.
Chris Masona52d9a82007-08-27 16:49:44 -0400323 */
324struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
Chris Masond1310b22008-01-24 16:13:08 -0500325 u64 start, u64 len)
Chris Masona52d9a82007-08-27 16:49:44 -0400326{
Li Zefaned64f062011-07-14 03:18:15 +0000327 return __lookup_extent_mapping(tree, start, len, 1);
Chris Masona52d9a82007-08-27 16:49:44 -0400328}
Chris Masona52d9a82007-08-27 16:49:44 -0400329
Christoph Hellwig9d2423c2008-06-11 21:52:17 -0400330/**
Chris Masonb917b7c2009-09-18 16:07:03 -0400331 * search_extent_mapping - find a nearby extent map
332 * @tree: tree to lookup in
333 * @start: byte offset to start the search
334 * @len: length of the lookup range
335 *
336 * Find and return the first extent_map struct in @tree that intersects the
337 * [start, len] range.
338 *
339 * If one can't be found, any nearby extent may be returned
340 */
341struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
342 u64 start, u64 len)
343{
Li Zefaned64f062011-07-14 03:18:15 +0000344 return __lookup_extent_mapping(tree, start, len, 0);
Chris Masonb917b7c2009-09-18 16:07:03 -0400345}
346
347/**
Christoph Hellwig9d2423c2008-06-11 21:52:17 -0400348 * remove_extent_mapping - removes an extent_map from the extent tree
349 * @tree: extent tree to remove from
350 * @em: extent map beeing removed
351 *
352 * Removes @em from @tree. No reference counts are dropped, and no checks
353 * are done to see if the range is in use
Chris Masona52d9a82007-08-27 16:49:44 -0400354 */
355int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
356{
Chris Masond1310b22008-01-24 16:13:08 -0500357 int ret = 0;
Chris Masona52d9a82007-08-27 16:49:44 -0400358
Chris Mason7f3c74f2008-07-18 12:01:11 -0400359 WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
Chris Masond1310b22008-01-24 16:13:08 -0500360 rb_erase(&em->rb_node, &tree->map);
361 em->in_tree = 0;
Chris Masona52d9a82007-08-27 16:49:44 -0400362 return ret;
363}