blob: a24a3f2fa13e6fe4a1670073933aa1de61490dc4 [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
31 * @mask: flags for memory allocations during tree operations
32 *
33 * Initialize the extent tree @tree. Should be called for each new inode
34 * or other user of the extent_map interface.
35 */
Chris Masond1310b22008-01-24 16:13:08 -050036void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask)
Chris Masona52d9a82007-08-27 16:49:44 -040037{
Eric Paris6bef4d32010-02-23 19:43:04 +000038 tree->map = RB_ROOT;
Chris Mason890871b2009-09-02 16:24:52 -040039 rwlock_init(&tree->lock);
Chris Masona52d9a82007-08-27 16:49:44 -040040}
Chris Masona52d9a82007-08-27 16:49:44 -040041
Christoph Hellwig9d2423c2008-06-11 21:52:17 -040042/**
43 * alloc_extent_map - allocate new extent map structure
44 * @mask: memory allocation flags
45 *
46 * Allocate a new extent_map structure. The new structure is
47 * returned with a reference count of one and needs to be
48 * freed using free_extent_map()
49 */
Chris Masona52d9a82007-08-27 16:49:44 -040050struct extent_map *alloc_extent_map(gfp_t mask)
51{
52 struct extent_map *em;
53 em = kmem_cache_alloc(extent_map_cache, mask);
Tsutomu Itohc26a9202011-02-14 00:45:29 +000054 if (!em)
55 return NULL;
Chris Masona52d9a82007-08-27 16:49:44 -040056 em->in_tree = 0;
Chris Masond1310b22008-01-24 16:13:08 -050057 em->flags = 0;
Li Zefan261507a02010-12-17 14:21:50 +080058 em->compress_type = BTRFS_COMPRESS_NONE;
Chris Masona52d9a82007-08-27 16:49:44 -040059 atomic_set(&em->refs, 1);
60 return em;
61}
Chris Masona52d9a82007-08-27 16:49:44 -040062
Christoph Hellwig9d2423c2008-06-11 21:52:17 -040063/**
64 * free_extent_map - drop reference count of an extent_map
65 * @em: extent map beeing releasead
66 *
67 * Drops the reference out on @em by one and free the structure
68 * if the reference count hits zero.
69 */
Chris Masona52d9a82007-08-27 16:49:44 -040070void free_extent_map(struct extent_map *em)
71{
Chris Mason2bf5a722007-08-30 11:54:02 -040072 if (!em)
73 return;
Chris Masond1310b22008-01-24 16:13:08 -050074 WARN_ON(atomic_read(&em->refs) == 0);
Chris Masona52d9a82007-08-27 16:49:44 -040075 if (atomic_dec_and_test(&em->refs)) {
76 WARN_ON(em->in_tree);
77 kmem_cache_free(extent_map_cache, em);
78 }
79}
Chris Masona52d9a82007-08-27 16:49:44 -040080
Chris Masona52d9a82007-08-27 16:49:44 -040081static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
82 struct rb_node *node)
83{
Chris Masond3977122009-01-05 21:25:51 -050084 struct rb_node **p = &root->rb_node;
85 struct rb_node *parent = NULL;
Chris Masond1310b22008-01-24 16:13:08 -050086 struct extent_map *entry;
Chris Masona52d9a82007-08-27 16:49:44 -040087
Chris Masond3977122009-01-05 21:25:51 -050088 while (*p) {
Chris Masona52d9a82007-08-27 16:49:44 -040089 parent = *p;
Chris Masond1310b22008-01-24 16:13:08 -050090 entry = rb_entry(parent, struct extent_map, rb_node);
91
92 WARN_ON(!entry->in_tree);
Chris Masona52d9a82007-08-27 16:49:44 -040093
94 if (offset < entry->start)
95 p = &(*p)->rb_left;
Chris Masond1310b22008-01-24 16:13:08 -050096 else if (offset >= extent_map_end(entry))
Chris Masona52d9a82007-08-27 16:49:44 -040097 p = &(*p)->rb_right;
98 else
99 return parent;
100 }
101
Chris Masond1310b22008-01-24 16:13:08 -0500102 entry = rb_entry(node, struct extent_map, rb_node);
Chris Masona52d9a82007-08-27 16:49:44 -0400103 entry->in_tree = 1;
104 rb_link_node(node, parent, p);
105 rb_insert_color(node, root);
106 return NULL;
107}
108
Chris Masond352ac62008-09-29 15:18:18 -0400109/*
110 * search through the tree for an extent_map with a given offset. If
111 * it can't be found, try to find some neighboring extents
112 */
Chris Masona52d9a82007-08-27 16:49:44 -0400113static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
Chris Mason5f564062008-01-22 16:47:59 -0500114 struct rb_node **prev_ret,
115 struct rb_node **next_ret)
Chris Masona52d9a82007-08-27 16:49:44 -0400116{
Chris Masond3977122009-01-05 21:25:51 -0500117 struct rb_node *n = root->rb_node;
Chris Masona52d9a82007-08-27 16:49:44 -0400118 struct rb_node *prev = NULL;
Chris Mason5f564062008-01-22 16:47:59 -0500119 struct rb_node *orig_prev = NULL;
Chris Masond1310b22008-01-24 16:13:08 -0500120 struct extent_map *entry;
121 struct extent_map *prev_entry = NULL;
Chris Masona52d9a82007-08-27 16:49:44 -0400122
Chris Masond3977122009-01-05 21:25:51 -0500123 while (n) {
Chris Masond1310b22008-01-24 16:13:08 -0500124 entry = rb_entry(n, struct extent_map, rb_node);
Chris Masona52d9a82007-08-27 16:49:44 -0400125 prev = n;
126 prev_entry = entry;
127
Chris Masond1310b22008-01-24 16:13:08 -0500128 WARN_ON(!entry->in_tree);
129
Chris Masona52d9a82007-08-27 16:49:44 -0400130 if (offset < entry->start)
131 n = n->rb_left;
Chris Masond1310b22008-01-24 16:13:08 -0500132 else if (offset >= extent_map_end(entry))
Chris Masona52d9a82007-08-27 16:49:44 -0400133 n = n->rb_right;
134 else
135 return n;
136 }
Chris Mason5f564062008-01-22 16:47:59 -0500137
138 if (prev_ret) {
139 orig_prev = prev;
Chris Masond3977122009-01-05 21:25:51 -0500140 while (prev && offset >= extent_map_end(prev_entry)) {
Chris Mason5f564062008-01-22 16:47:59 -0500141 prev = rb_next(prev);
Chris Masond1310b22008-01-24 16:13:08 -0500142 prev_entry = rb_entry(prev, struct extent_map, rb_node);
Chris Mason5f564062008-01-22 16:47:59 -0500143 }
144 *prev_ret = prev;
145 prev = orig_prev;
Chris Masona52d9a82007-08-27 16:49:44 -0400146 }
Chris Mason5f564062008-01-22 16:47:59 -0500147
148 if (next_ret) {
Chris Masond1310b22008-01-24 16:13:08 -0500149 prev_entry = rb_entry(prev, struct extent_map, rb_node);
Chris Masond3977122009-01-05 21:25:51 -0500150 while (prev && offset < prev_entry->start) {
Chris Mason5f564062008-01-22 16:47:59 -0500151 prev = rb_prev(prev);
Chris Masond1310b22008-01-24 16:13:08 -0500152 prev_entry = rb_entry(prev, struct extent_map, rb_node);
Chris Mason5f564062008-01-22 16:47:59 -0500153 }
154 *next_ret = prev;
155 }
Chris Masona52d9a82007-08-27 16:49:44 -0400156 return NULL;
157}
158
Chris Masond352ac62008-09-29 15:18:18 -0400159/* check to see if two extent_map structs are adjacent and safe to merge */
Chris Masond1310b22008-01-24 16:13:08 -0500160static int mergable_maps(struct extent_map *prev, struct extent_map *next)
Chris Masona52d9a82007-08-27 16:49:44 -0400161{
Chris Mason7f3c74f2008-07-18 12:01:11 -0400162 if (test_bit(EXTENT_FLAG_PINNED, &prev->flags))
163 return 0;
164
Chris Masonc8b97812008-10-29 14:49:59 -0400165 /*
166 * don't merge compressed extents, we need to know their
167 * actual size
168 */
169 if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags))
170 return 0;
171
Chris Masond1310b22008-01-24 16:13:08 -0500172 if (extent_map_end(prev) == next->start &&
173 prev->flags == next->flags &&
174 prev->bdev == next->bdev &&
175 ((next->block_start == EXTENT_MAP_HOLE &&
176 prev->block_start == EXTENT_MAP_HOLE) ||
177 (next->block_start == EXTENT_MAP_INLINE &&
178 prev->block_start == EXTENT_MAP_INLINE) ||
179 (next->block_start == EXTENT_MAP_DELALLOC &&
180 prev->block_start == EXTENT_MAP_DELALLOC) ||
181 (next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
182 next->block_start == extent_map_block_end(prev)))) {
183 return 1;
184 }
Chris Masona52d9a82007-08-27 16:49:44 -0400185 return 0;
186}
187
Chris Masona1ed8352009-09-11 12:27:37 -0400188int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)
189{
190 int ret = 0;
191 struct extent_map *merge = NULL;
192 struct rb_node *rb;
193 struct extent_map *em;
194
195 write_lock(&tree->lock);
196 em = lookup_extent_mapping(tree, start, len);
197
Dan Carpenter4eb39912009-11-10 09:01:43 +0000198 WARN_ON(!em || em->start != start);
Chris Masona1ed8352009-09-11 12:27:37 -0400199
200 if (!em)
201 goto out;
202
203 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
204
205 if (em->start != 0) {
206 rb = rb_prev(&em->rb_node);
207 if (rb)
208 merge = rb_entry(rb, struct extent_map, rb_node);
209 if (rb && mergable_maps(merge, em)) {
210 em->start = merge->start;
211 em->len += merge->len;
212 em->block_len += merge->block_len;
213 em->block_start = merge->block_start;
214 merge->in_tree = 0;
215 rb_erase(&merge->rb_node, &tree->map);
216 free_extent_map(merge);
217 }
218 }
219
220 rb = rb_next(&em->rb_node);
221 if (rb)
222 merge = rb_entry(rb, struct extent_map, rb_node);
223 if (rb && mergable_maps(em, merge)) {
224 em->len += merge->len;
225 em->block_len += merge->len;
226 rb_erase(&merge->rb_node, &tree->map);
227 merge->in_tree = 0;
228 free_extent_map(merge);
229 }
230
231 free_extent_map(em);
232out:
233 write_unlock(&tree->lock);
234 return ret;
235
236}
237
Christoph Hellwig9d2423c2008-06-11 21:52:17 -0400238/**
239 * add_extent_mapping - add new extent map to the extent tree
240 * @tree: tree to insert new map in
241 * @em: map to insert
242 *
243 * Insert @em into @tree or perform a simple forward/backward merge with
244 * existing mappings. The extent_map struct passed in will be inserted
245 * into the tree directly, with an additional reference taken, or a
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300246 * reference dropped if the merge attempt was successful.
Chris Masona52d9a82007-08-27 16:49:44 -0400247 */
248int add_extent_mapping(struct extent_map_tree *tree,
249 struct extent_map *em)
250{
251 int ret = 0;
Chris Masond1310b22008-01-24 16:13:08 -0500252 struct extent_map *merge = NULL;
Chris Masona52d9a82007-08-27 16:49:44 -0400253 struct rb_node *rb;
Chris Mason7c2fe322008-08-20 08:51:50 -0400254 struct extent_map *exist;
Chris Masona52d9a82007-08-27 16:49:44 -0400255
Chris Mason7c2fe322008-08-20 08:51:50 -0400256 exist = lookup_extent_mapping(tree, em->start, em->len);
257 if (exist) {
258 free_extent_map(exist);
259 ret = -EEXIST;
260 goto out;
261 }
Chris Masond1310b22008-01-24 16:13:08 -0500262 rb = tree_insert(&tree->map, em->start, &em->rb_node);
Chris Masona52d9a82007-08-27 16:49:44 -0400263 if (rb) {
Chris Masona52d9a82007-08-27 16:49:44 -0400264 ret = -EEXIST;
265 goto out;
266 }
267 atomic_inc(&em->refs);
268 if (em->start != 0) {
269 rb = rb_prev(&em->rb_node);
270 if (rb)
Chris Masond1310b22008-01-24 16:13:08 -0500271 merge = rb_entry(rb, struct extent_map, rb_node);
272 if (rb && mergable_maps(merge, em)) {
273 em->start = merge->start;
274 em->len += merge->len;
Chris Masonc8b97812008-10-29 14:49:59 -0400275 em->block_len += merge->block_len;
Chris Masond1310b22008-01-24 16:13:08 -0500276 em->block_start = merge->block_start;
277 merge->in_tree = 0;
278 rb_erase(&merge->rb_node, &tree->map);
279 free_extent_map(merge);
Chris Masona52d9a82007-08-27 16:49:44 -0400280 }
281 }
Chris Masond1310b22008-01-24 16:13:08 -0500282 rb = rb_next(&em->rb_node);
283 if (rb)
284 merge = rb_entry(rb, struct extent_map, rb_node);
285 if (rb && mergable_maps(em, merge)) {
286 em->len += merge->len;
Chris Masonc8b97812008-10-29 14:49:59 -0400287 em->block_len += merge->len;
Chris Masond1310b22008-01-24 16:13:08 -0500288 rb_erase(&merge->rb_node, &tree->map);
289 merge->in_tree = 0;
290 free_extent_map(merge);
291 }
Chris Masona52d9a82007-08-27 16:49:44 -0400292out:
Chris Masona52d9a82007-08-27 16:49:44 -0400293 return ret;
294}
Chris Masona52d9a82007-08-27 16:49:44 -0400295
Chris Masond352ac62008-09-29 15:18:18 -0400296/* simple helper to do math around the end of an extent, handling wrap */
Chris Masond1310b22008-01-24 16:13:08 -0500297static u64 range_end(u64 start, u64 len)
298{
299 if (start + len < start)
300 return (u64)-1;
301 return start + len;
302}
303
Christoph Hellwig9d2423c2008-06-11 21:52:17 -0400304/**
305 * lookup_extent_mapping - lookup extent_map
306 * @tree: tree to lookup in
307 * @start: byte offset to start the search
308 * @len: length of the lookup range
309 *
310 * Find and return the first extent_map struct in @tree that intersects the
311 * [start, len] range. There may be additional objects in the tree that
312 * intersect, so check the object returned carefully to make sure that no
313 * additional lookups are needed.
Chris Masona52d9a82007-08-27 16:49:44 -0400314 */
315struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
Chris Masond1310b22008-01-24 16:13:08 -0500316 u64 start, u64 len)
Chris Masona52d9a82007-08-27 16:49:44 -0400317{
318 struct extent_map *em;
319 struct rb_node *rb_node;
Christoph Hellwig306929f2008-06-10 10:21:04 -0400320 struct rb_node *prev = NULL;
321 struct rb_node *next = NULL;
322 u64 end = range_end(start, len);
323
Chris Mason5f564062008-01-22 16:47:59 -0500324 rb_node = __tree_search(&tree->map, start, &prev, &next);
325 if (!rb_node && prev) {
326 em = rb_entry(prev, struct extent_map, rb_node);
Chris Masond1310b22008-01-24 16:13:08 -0500327 if (end > em->start && start < extent_map_end(em))
Chris Mason5f564062008-01-22 16:47:59 -0500328 goto found;
329 }
330 if (!rb_node && next) {
331 em = rb_entry(next, struct extent_map, rb_node);
Chris Masond1310b22008-01-24 16:13:08 -0500332 if (end > em->start && start < extent_map_end(em))
Chris Mason5f564062008-01-22 16:47:59 -0500333 goto found;
334 }
Chris Masona52d9a82007-08-27 16:49:44 -0400335 if (!rb_node) {
336 em = NULL;
337 goto out;
338 }
339 if (IS_ERR(rb_node)) {
Julia Lawalld0b678c2010-10-29 15:14:23 -0400340 em = ERR_CAST(rb_node);
Chris Masona52d9a82007-08-27 16:49:44 -0400341 goto out;
342 }
343 em = rb_entry(rb_node, struct extent_map, rb_node);
Chris Masond1310b22008-01-24 16:13:08 -0500344 if (end > em->start && start < extent_map_end(em))
345 goto found;
346
347 em = NULL;
348 goto out;
349
Chris Mason5f564062008-01-22 16:47:59 -0500350found:
Chris Masona52d9a82007-08-27 16:49:44 -0400351 atomic_inc(&em->refs);
352out:
Chris Masona52d9a82007-08-27 16:49:44 -0400353 return em;
354}
Chris Masona52d9a82007-08-27 16:49:44 -0400355
Christoph Hellwig9d2423c2008-06-11 21:52:17 -0400356/**
Chris Masonb917b7c2009-09-18 16:07:03 -0400357 * search_extent_mapping - find a nearby extent map
358 * @tree: tree to lookup in
359 * @start: byte offset to start the search
360 * @len: length of the lookup range
361 *
362 * Find and return the first extent_map struct in @tree that intersects the
363 * [start, len] range.
364 *
365 * If one can't be found, any nearby extent may be returned
366 */
367struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
368 u64 start, u64 len)
369{
370 struct extent_map *em;
371 struct rb_node *rb_node;
372 struct rb_node *prev = NULL;
373 struct rb_node *next = NULL;
374
375 rb_node = __tree_search(&tree->map, start, &prev, &next);
376 if (!rb_node && prev) {
377 em = rb_entry(prev, struct extent_map, rb_node);
378 goto found;
379 }
380 if (!rb_node && next) {
381 em = rb_entry(next, struct extent_map, rb_node);
382 goto found;
383 }
384 if (!rb_node) {
385 em = NULL;
386 goto out;
387 }
388 if (IS_ERR(rb_node)) {
Julia Lawalld0b678c2010-10-29 15:14:23 -0400389 em = ERR_CAST(rb_node);
Chris Masonb917b7c2009-09-18 16:07:03 -0400390 goto out;
391 }
392 em = rb_entry(rb_node, struct extent_map, rb_node);
393 goto found;
394
395 em = NULL;
396 goto out;
397
398found:
399 atomic_inc(&em->refs);
400out:
401 return em;
402}
403
404/**
Christoph Hellwig9d2423c2008-06-11 21:52:17 -0400405 * remove_extent_mapping - removes an extent_map from the extent tree
406 * @tree: extent tree to remove from
407 * @em: extent map beeing removed
408 *
409 * Removes @em from @tree. No reference counts are dropped, and no checks
410 * are done to see if the range is in use
Chris Masona52d9a82007-08-27 16:49:44 -0400411 */
412int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
413{
Chris Masond1310b22008-01-24 16:13:08 -0500414 int ret = 0;
Chris Masona52d9a82007-08-27 16:49:44 -0400415
Chris Mason7f3c74f2008-07-18 12:01:11 -0400416 WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
Chris Masond1310b22008-01-24 16:13:08 -0500417 rb_erase(&em->rb_node, &tree->map);
418 em->in_tree = 0;
Chris Masona52d9a82007-08-27 16:49:44 -0400419 return ret;
420}