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a52d9a80 CM |
1 | #include <linux/bitops.h> |
2 | #include <linux/slab.h> | |
3 | #include <linux/bio.h> | |
4 | #include <linux/mm.h> | |
5 | #include <linux/gfp.h> | |
6 | #include <linux/pagemap.h> | |
7 | #include <linux/page-flags.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/spinlock.h> | |
10 | #include <linux/blkdev.h> | |
11 | #include "extent_map.h" | |
12 | ||
13 | static struct kmem_cache *extent_map_cache; | |
14 | static struct kmem_cache *extent_state_cache; | |
15 | ||
16 | struct tree_entry { | |
17 | u64 start; | |
18 | u64 end; | |
19 | int in_tree; | |
20 | struct rb_node rb_node; | |
21 | }; | |
22 | ||
23 | /* bits for the extent state */ | |
24 | #define EXTENT_DIRTY 1 | |
25 | #define EXTENT_WRITEBACK (1 << 1) | |
26 | #define EXTENT_UPTODATE (1 << 2) | |
27 | #define EXTENT_LOCKED (1 << 3) | |
28 | #define EXTENT_NEW (1 << 4) | |
29 | #define EXTENT_DELALLOC (1 << 5) | |
30 | ||
31 | #define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK) | |
32 | ||
33 | static LIST_HEAD(all_states); | |
34 | spinlock_t state_lock = SPIN_LOCK_UNLOCKED; | |
35 | ||
36 | void __init extent_map_init(void) | |
37 | { | |
38 | extent_map_cache = kmem_cache_create("extent_map", | |
39 | sizeof(struct extent_map), 0, | |
40 | SLAB_RECLAIM_ACCOUNT | | |
41 | SLAB_DESTROY_BY_RCU, | |
42 | NULL); | |
43 | extent_state_cache = kmem_cache_create("extent_state", | |
44 | sizeof(struct extent_state), 0, | |
45 | SLAB_RECLAIM_ACCOUNT | | |
46 | SLAB_DESTROY_BY_RCU, | |
47 | NULL); | |
48 | } | |
49 | ||
50 | void __exit extent_map_exit(void) | |
51 | { | |
52 | while(!list_empty(&all_states)) { | |
53 | struct extent_state *state; | |
54 | struct list_head *cur = all_states.next; | |
55 | state = list_entry(cur, struct extent_state, list); | |
56 | printk("found leaked state %Lu %Lu state %d in_tree %d\n", | |
57 | state->start, state->end, state->state, state->in_tree); | |
58 | list_del(&state->list); | |
59 | kfree(state); | |
60 | } | |
61 | if (extent_map_cache) | |
62 | kmem_cache_destroy(extent_map_cache); | |
63 | if (extent_state_cache) | |
64 | kmem_cache_destroy(extent_state_cache); | |
65 | } | |
66 | ||
67 | void extent_map_tree_init(struct extent_map_tree *tree, | |
68 | struct address_space *mapping, gfp_t mask) | |
69 | { | |
70 | tree->map.rb_node = NULL; | |
71 | tree->state.rb_node = NULL; | |
72 | rwlock_init(&tree->lock); | |
73 | tree->mapping = mapping; | |
74 | } | |
75 | EXPORT_SYMBOL(extent_map_tree_init); | |
76 | ||
77 | struct extent_map *alloc_extent_map(gfp_t mask) | |
78 | { | |
79 | struct extent_map *em; | |
80 | em = kmem_cache_alloc(extent_map_cache, mask); | |
81 | if (!em || IS_ERR(em)) | |
82 | return em; | |
83 | em->in_tree = 0; | |
84 | atomic_set(&em->refs, 1); | |
85 | return em; | |
86 | } | |
87 | EXPORT_SYMBOL(alloc_extent_map); | |
88 | ||
89 | void free_extent_map(struct extent_map *em) | |
90 | { | |
91 | if (atomic_dec_and_test(&em->refs)) { | |
92 | WARN_ON(em->in_tree); | |
93 | kmem_cache_free(extent_map_cache, em); | |
94 | } | |
95 | } | |
96 | EXPORT_SYMBOL(free_extent_map); | |
97 | ||
98 | ||
99 | struct extent_state *alloc_extent_state(gfp_t mask) | |
100 | { | |
101 | struct extent_state *state; | |
102 | state = kmem_cache_alloc(extent_state_cache, mask); | |
103 | if (!state || IS_ERR(state)) | |
104 | return state; | |
105 | state->state = 0; | |
106 | state->in_tree = 0; | |
107 | atomic_set(&state->refs, 1); | |
108 | init_waitqueue_head(&state->wq); | |
109 | spin_lock_irq(&state_lock); | |
110 | list_add(&state->list, &all_states); | |
111 | spin_unlock_irq(&state_lock); | |
112 | return state; | |
113 | } | |
114 | EXPORT_SYMBOL(alloc_extent_state); | |
115 | ||
116 | void free_extent_state(struct extent_state *state) | |
117 | { | |
118 | if (atomic_dec_and_test(&state->refs)) { | |
119 | WARN_ON(state->in_tree); | |
120 | spin_lock_irq(&state_lock); | |
121 | list_del_init(&state->list); | |
122 | spin_unlock_irq(&state_lock); | |
123 | kmem_cache_free(extent_state_cache, state); | |
124 | } | |
125 | } | |
126 | EXPORT_SYMBOL(free_extent_state); | |
127 | ||
128 | static struct rb_node *tree_insert(struct rb_root *root, u64 offset, | |
129 | struct rb_node *node) | |
130 | { | |
131 | struct rb_node ** p = &root->rb_node; | |
132 | struct rb_node * parent = NULL; | |
133 | struct tree_entry *entry; | |
134 | ||
135 | while(*p) { | |
136 | parent = *p; | |
137 | entry = rb_entry(parent, struct tree_entry, rb_node); | |
138 | ||
139 | if (offset < entry->start) | |
140 | p = &(*p)->rb_left; | |
141 | else if (offset > entry->end) | |
142 | p = &(*p)->rb_right; | |
143 | else | |
144 | return parent; | |
145 | } | |
146 | ||
147 | entry = rb_entry(node, struct tree_entry, rb_node); | |
148 | entry->in_tree = 1; | |
149 | rb_link_node(node, parent, p); | |
150 | rb_insert_color(node, root); | |
151 | return NULL; | |
152 | } | |
153 | ||
154 | static struct rb_node *__tree_search(struct rb_root *root, u64 offset, | |
155 | struct rb_node **prev_ret) | |
156 | { | |
157 | struct rb_node * n = root->rb_node; | |
158 | struct rb_node *prev = NULL; | |
159 | struct tree_entry *entry; | |
160 | struct tree_entry *prev_entry = NULL; | |
161 | ||
162 | while(n) { | |
163 | entry = rb_entry(n, struct tree_entry, rb_node); | |
164 | prev = n; | |
165 | prev_entry = entry; | |
166 | ||
167 | if (offset < entry->start) | |
168 | n = n->rb_left; | |
169 | else if (offset > entry->end) | |
170 | n = n->rb_right; | |
171 | else | |
172 | return n; | |
173 | } | |
174 | if (!prev_ret) | |
175 | return NULL; | |
176 | while(prev && offset > prev_entry->end) { | |
177 | prev = rb_next(prev); | |
178 | prev_entry = rb_entry(prev, struct tree_entry, rb_node); | |
179 | } | |
180 | *prev_ret = prev; | |
181 | return NULL; | |
182 | } | |
183 | ||
184 | static inline struct rb_node *tree_search(struct rb_root *root, u64 offset) | |
185 | { | |
186 | struct rb_node *prev; | |
187 | struct rb_node *ret; | |
188 | ret = __tree_search(root, offset, &prev); | |
189 | if (!ret) | |
190 | return prev; | |
191 | return ret; | |
192 | } | |
193 | ||
194 | static int tree_delete(struct rb_root *root, u64 offset) | |
195 | { | |
196 | struct rb_node *node; | |
197 | struct tree_entry *entry; | |
198 | ||
199 | node = __tree_search(root, offset, NULL); | |
200 | if (!node) | |
201 | return -ENOENT; | |
202 | entry = rb_entry(node, struct tree_entry, rb_node); | |
203 | entry->in_tree = 0; | |
204 | rb_erase(node, root); | |
205 | return 0; | |
206 | } | |
207 | ||
208 | /* | |
209 | * add_extent_mapping tries a simple backward merge with existing | |
210 | * mappings. The extent_map struct passed in will be inserted into | |
211 | * the tree directly (no copies made, just a reference taken). | |
212 | */ | |
213 | int add_extent_mapping(struct extent_map_tree *tree, | |
214 | struct extent_map *em) | |
215 | { | |
216 | int ret = 0; | |
217 | struct extent_map *prev = NULL; | |
218 | struct rb_node *rb; | |
219 | ||
220 | write_lock_irq(&tree->lock); | |
221 | rb = tree_insert(&tree->map, em->end, &em->rb_node); | |
222 | if (rb) { | |
223 | prev = rb_entry(rb, struct extent_map, rb_node); | |
224 | printk("found extent map %Lu %Lu on insert of %Lu %Lu\n", prev->start, prev->end, em->start, em->end); | |
225 | ret = -EEXIST; | |
226 | goto out; | |
227 | } | |
228 | atomic_inc(&em->refs); | |
229 | if (em->start != 0) { | |
230 | rb = rb_prev(&em->rb_node); | |
231 | if (rb) | |
232 | prev = rb_entry(rb, struct extent_map, rb_node); | |
233 | if (prev && prev->end + 1 == em->start && | |
234 | ((em->block_start == 0 && prev->block_start == 0) || | |
235 | (em->block_start == prev->block_end + 1))) { | |
236 | em->start = prev->start; | |
237 | em->block_start = prev->block_start; | |
238 | rb_erase(&prev->rb_node, &tree->map); | |
239 | prev->in_tree = 0; | |
240 | free_extent_map(prev); | |
241 | } | |
242 | } | |
243 | out: | |
244 | write_unlock_irq(&tree->lock); | |
245 | return ret; | |
246 | } | |
247 | EXPORT_SYMBOL(add_extent_mapping); | |
248 | ||
249 | /* | |
250 | * lookup_extent_mapping returns the first extent_map struct in the | |
251 | * tree that intersects the [start, end] (inclusive) range. There may | |
252 | * be additional objects in the tree that intersect, so check the object | |
253 | * returned carefully to make sure you don't need additional lookups. | |
254 | */ | |
255 | struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree, | |
256 | u64 start, u64 end) | |
257 | { | |
258 | struct extent_map *em; | |
259 | struct rb_node *rb_node; | |
260 | ||
261 | read_lock_irq(&tree->lock); | |
262 | rb_node = tree_search(&tree->map, start); | |
263 | if (!rb_node) { | |
264 | em = NULL; | |
265 | goto out; | |
266 | } | |
267 | if (IS_ERR(rb_node)) { | |
268 | em = ERR_PTR(PTR_ERR(rb_node)); | |
269 | goto out; | |
270 | } | |
271 | em = rb_entry(rb_node, struct extent_map, rb_node); | |
272 | if (em->end < start || em->start > end) { | |
273 | em = NULL; | |
274 | goto out; | |
275 | } | |
276 | atomic_inc(&em->refs); | |
277 | out: | |
278 | read_unlock_irq(&tree->lock); | |
279 | return em; | |
280 | } | |
281 | EXPORT_SYMBOL(lookup_extent_mapping); | |
282 | ||
283 | /* | |
284 | * removes an extent_map struct from the tree. No reference counts are | |
285 | * dropped, and no checks are done to see if the range is in use | |
286 | */ | |
287 | int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em) | |
288 | { | |
289 | int ret; | |
290 | ||
291 | write_lock_irq(&tree->lock); | |
292 | ret = tree_delete(&tree->map, em->end); | |
293 | write_unlock_irq(&tree->lock); | |
294 | return ret; | |
295 | } | |
296 | EXPORT_SYMBOL(remove_extent_mapping); | |
297 | ||
298 | /* | |
299 | * utility function to look for merge candidates inside a given range. | |
300 | * Any extents with matching state are merged together into a single | |
301 | * extent in the tree. Extents with EXTENT_IO in their state field | |
302 | * are not merged because the end_io handlers need to be able to do | |
303 | * operations on them without sleeping (or doing allocations/splits). | |
304 | * | |
305 | * This should be called with the tree lock held. | |
306 | */ | |
307 | static int merge_state(struct extent_map_tree *tree, | |
308 | struct extent_state *state) | |
309 | { | |
310 | struct extent_state *other; | |
311 | struct rb_node *other_node; | |
312 | ||
313 | if (state->state & EXTENT_IOBITS) | |
314 | return 0; | |
315 | ||
316 | other_node = rb_prev(&state->rb_node); | |
317 | if (other_node) { | |
318 | other = rb_entry(other_node, struct extent_state, rb_node); | |
319 | if (other->end == state->start - 1 && | |
320 | other->state == state->state) { | |
321 | state->start = other->start; | |
322 | other->in_tree = 0; | |
323 | rb_erase(&other->rb_node, &tree->state); | |
324 | free_extent_state(other); | |
325 | } | |
326 | } | |
327 | other_node = rb_next(&state->rb_node); | |
328 | if (other_node) { | |
329 | other = rb_entry(other_node, struct extent_state, rb_node); | |
330 | if (other->start == state->end + 1 && | |
331 | other->state == state->state) { | |
332 | other->start = state->start; | |
333 | state->in_tree = 0; | |
334 | rb_erase(&state->rb_node, &tree->state); | |
335 | free_extent_state(state); | |
336 | } | |
337 | } | |
338 | return 0; | |
339 | } | |
340 | ||
341 | /* | |
342 | * insert an extent_state struct into the tree. 'bits' are set on the | |
343 | * struct before it is inserted. | |
344 | * | |
345 | * This may return -EEXIST if the extent is already there, in which case the | |
346 | * state struct is freed. | |
347 | * | |
348 | * The tree lock is not taken internally. This is a utility function and | |
349 | * probably isn't what you want to call (see set/clear_extent_bit). | |
350 | */ | |
351 | static int insert_state(struct extent_map_tree *tree, | |
352 | struct extent_state *state, u64 start, u64 end, | |
353 | int bits) | |
354 | { | |
355 | struct rb_node *node; | |
356 | ||
357 | if (end < start) { | |
358 | printk("end < start %Lu %Lu\n", end, start); | |
359 | WARN_ON(1); | |
360 | } | |
361 | state->state |= bits; | |
362 | state->start = start; | |
363 | state->end = end; | |
364 | if ((end & 4095) == 0) { | |
365 | printk("insert state %Lu %Lu strange end\n", start, end); | |
366 | WARN_ON(1); | |
367 | } | |
368 | node = tree_insert(&tree->state, end, &state->rb_node); | |
369 | if (node) { | |
370 | struct extent_state *found; | |
371 | found = rb_entry(node, struct extent_state, rb_node); | |
372 | printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, start, end); | |
373 | free_extent_state(state); | |
374 | return -EEXIST; | |
375 | } | |
376 | merge_state(tree, state); | |
377 | return 0; | |
378 | } | |
379 | ||
380 | /* | |
381 | * split a given extent state struct in two, inserting the preallocated | |
382 | * struct 'prealloc' as the newly created second half. 'split' indicates an | |
383 | * offset inside 'orig' where it should be split. | |
384 | * | |
385 | * Before calling, | |
386 | * the tree has 'orig' at [orig->start, orig->end]. After calling, there | |
387 | * are two extent state structs in the tree: | |
388 | * prealloc: [orig->start, split - 1] | |
389 | * orig: [ split, orig->end ] | |
390 | * | |
391 | * The tree locks are not taken by this function. They need to be held | |
392 | * by the caller. | |
393 | */ | |
394 | static int split_state(struct extent_map_tree *tree, struct extent_state *orig, | |
395 | struct extent_state *prealloc, u64 split) | |
396 | { | |
397 | struct rb_node *node; | |
398 | prealloc->start = orig->start; | |
399 | prealloc->end = split - 1; | |
400 | prealloc->state = orig->state; | |
401 | orig->start = split; | |
402 | if ((prealloc->end & 4095) == 0) { | |
403 | printk("insert state %Lu %Lu strange end\n", prealloc->start, | |
404 | prealloc->end); | |
405 | WARN_ON(1); | |
406 | } | |
407 | node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node); | |
408 | if (node) { | |
409 | struct extent_state *found; | |
410 | found = rb_entry(node, struct extent_state, rb_node); | |
411 | printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, prealloc->start, prealloc->end); | |
412 | free_extent_state(prealloc); | |
413 | return -EEXIST; | |
414 | } | |
415 | return 0; | |
416 | } | |
417 | ||
418 | /* | |
419 | * utility function to clear some bits in an extent state struct. | |
420 | * it will optionally wake up any one waiting on this state (wake == 1), or | |
421 | * forcibly remove the state from the tree (delete == 1). | |
422 | * | |
423 | * If no bits are set on the state struct after clearing things, the | |
424 | * struct is freed and removed from the tree | |
425 | */ | |
426 | static int clear_state_bit(struct extent_map_tree *tree, | |
427 | struct extent_state *state, int bits, int wake, | |
428 | int delete) | |
429 | { | |
430 | int ret = state->state & bits; | |
431 | state->state &= ~bits; | |
432 | if (wake) | |
433 | wake_up(&state->wq); | |
434 | if (delete || state->state == 0) { | |
435 | if (state->in_tree) { | |
436 | rb_erase(&state->rb_node, &tree->state); | |
437 | state->in_tree = 0; | |
438 | free_extent_state(state); | |
439 | } else { | |
440 | WARN_ON(1); | |
441 | } | |
442 | } else { | |
443 | merge_state(tree, state); | |
444 | } | |
445 | return ret; | |
446 | } | |
447 | ||
448 | /* | |
449 | * clear some bits on a range in the tree. This may require splitting | |
450 | * or inserting elements in the tree, so the gfp mask is used to | |
451 | * indicate which allocations or sleeping are allowed. | |
452 | * | |
453 | * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove | |
454 | * the given range from the tree regardless of state (ie for truncate). | |
455 | * | |
456 | * the range [start, end] is inclusive. | |
457 | * | |
458 | * This takes the tree lock, and returns < 0 on error, > 0 if any of the | |
459 | * bits were already set, or zero if none of the bits were already set. | |
460 | */ | |
461 | int clear_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, | |
462 | int bits, int wake, int delete, gfp_t mask) | |
463 | { | |
464 | struct extent_state *state; | |
465 | struct extent_state *prealloc = NULL; | |
466 | struct rb_node *node; | |
467 | int err; | |
468 | int set = 0; | |
469 | ||
470 | again: | |
471 | if (!prealloc && (mask & __GFP_WAIT)) { | |
472 | prealloc = alloc_extent_state(mask); | |
473 | if (!prealloc) | |
474 | return -ENOMEM; | |
475 | } | |
476 | ||
477 | write_lock_irq(&tree->lock); | |
478 | /* | |
479 | * this search will find the extents that end after | |
480 | * our range starts | |
481 | */ | |
482 | node = tree_search(&tree->state, start); | |
483 | if (!node) | |
484 | goto out; | |
485 | state = rb_entry(node, struct extent_state, rb_node); | |
486 | if (state->start > end) | |
487 | goto out; | |
488 | WARN_ON(state->end < start); | |
489 | ||
490 | /* | |
491 | * | ---- desired range ---- | | |
492 | * | state | or | |
493 | * | ------------- state -------------- | | |
494 | * | |
495 | * We need to split the extent we found, and may flip | |
496 | * bits on second half. | |
497 | * | |
498 | * If the extent we found extends past our range, we | |
499 | * just split and search again. It'll get split again | |
500 | * the next time though. | |
501 | * | |
502 | * If the extent we found is inside our range, we clear | |
503 | * the desired bit on it. | |
504 | */ | |
505 | ||
506 | if (state->start < start) { | |
507 | err = split_state(tree, state, prealloc, start); | |
508 | BUG_ON(err == -EEXIST); | |
509 | prealloc = NULL; | |
510 | if (err) | |
511 | goto out; | |
512 | if (state->end <= end) { | |
513 | start = state->end + 1; | |
514 | set |= clear_state_bit(tree, state, bits, | |
515 | wake, delete); | |
516 | } else { | |
517 | start = state->start; | |
518 | } | |
519 | goto search_again; | |
520 | } | |
521 | /* | |
522 | * | ---- desired range ---- | | |
523 | * | state | | |
524 | * We need to split the extent, and clear the bit | |
525 | * on the first half | |
526 | */ | |
527 | if (state->start <= end && state->end > end) { | |
528 | err = split_state(tree, state, prealloc, end + 1); | |
529 | BUG_ON(err == -EEXIST); | |
530 | ||
531 | if (wake) | |
532 | wake_up(&state->wq); | |
533 | set |= clear_state_bit(tree, prealloc, bits, | |
534 | wake, delete); | |
535 | prealloc = NULL; | |
536 | goto out; | |
537 | } | |
538 | ||
539 | start = state->end + 1; | |
540 | set |= clear_state_bit(tree, state, bits, wake, delete); | |
541 | goto search_again; | |
542 | ||
543 | out: | |
544 | write_unlock_irq(&tree->lock); | |
545 | if (prealloc) | |
546 | free_extent_state(prealloc); | |
547 | ||
548 | return set; | |
549 | ||
550 | search_again: | |
551 | if (start >= end) | |
552 | goto out; | |
553 | write_unlock_irq(&tree->lock); | |
554 | if (mask & __GFP_WAIT) | |
555 | cond_resched(); | |
556 | goto again; | |
557 | } | |
558 | EXPORT_SYMBOL(clear_extent_bit); | |
559 | ||
560 | static int wait_on_state(struct extent_map_tree *tree, | |
561 | struct extent_state *state) | |
562 | { | |
563 | DEFINE_WAIT(wait); | |
564 | prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE); | |
565 | read_unlock_irq(&tree->lock); | |
566 | schedule(); | |
567 | read_lock_irq(&tree->lock); | |
568 | finish_wait(&state->wq, &wait); | |
569 | return 0; | |
570 | } | |
571 | ||
572 | /* | |
573 | * waits for one or more bits to clear on a range in the state tree. | |
574 | * The range [start, end] is inclusive. | |
575 | * The tree lock is taken by this function | |
576 | */ | |
577 | int wait_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits) | |
578 | { | |
579 | struct extent_state *state; | |
580 | struct rb_node *node; | |
581 | ||
582 | read_lock_irq(&tree->lock); | |
583 | again: | |
584 | while (1) { | |
585 | /* | |
586 | * this search will find all the extents that end after | |
587 | * our range starts | |
588 | */ | |
589 | node = tree_search(&tree->state, start); | |
590 | if (!node) | |
591 | break; | |
592 | ||
593 | state = rb_entry(node, struct extent_state, rb_node); | |
594 | ||
595 | if (state->start > end) | |
596 | goto out; | |
597 | ||
598 | if (state->state & bits) { | |
599 | start = state->start; | |
600 | atomic_inc(&state->refs); | |
601 | wait_on_state(tree, state); | |
602 | free_extent_state(state); | |
603 | goto again; | |
604 | } | |
605 | start = state->end + 1; | |
606 | ||
607 | if (start > end) | |
608 | break; | |
609 | ||
610 | if (need_resched()) { | |
611 | read_unlock_irq(&tree->lock); | |
612 | cond_resched(); | |
613 | read_lock_irq(&tree->lock); | |
614 | } | |
615 | } | |
616 | out: | |
617 | read_unlock_irq(&tree->lock); | |
618 | return 0; | |
619 | } | |
620 | EXPORT_SYMBOL(wait_extent_bit); | |
621 | ||
622 | /* | |
623 | * set some bits on a range in the tree. This may require allocations | |
624 | * or sleeping, so the gfp mask is used to indicate what is allowed. | |
625 | * | |
626 | * If 'exclusive' == 1, this will fail with -EEXIST if some part of the | |
627 | * range already has the desired bits set. The start of the existing | |
628 | * range is returned in failed_start in this case. | |
629 | * | |
630 | * [start, end] is inclusive | |
631 | * This takes the tree lock. | |
632 | */ | |
633 | int set_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits, | |
634 | int exclusive, u64 *failed_start, gfp_t mask) | |
635 | { | |
636 | struct extent_state *state; | |
637 | struct extent_state *prealloc = NULL; | |
638 | struct rb_node *node; | |
639 | int err = 0; | |
640 | int set; | |
641 | u64 last_start; | |
642 | u64 last_end; | |
643 | again: | |
644 | if (!prealloc && (mask & __GFP_WAIT)) { | |
645 | prealloc = alloc_extent_state(mask); | |
646 | if (!prealloc) | |
647 | return -ENOMEM; | |
648 | } | |
649 | ||
650 | write_lock_irq(&tree->lock); | |
651 | /* | |
652 | * this search will find all the extents that end after | |
653 | * our range starts. | |
654 | */ | |
655 | node = tree_search(&tree->state, start); | |
656 | if (!node) { | |
657 | err = insert_state(tree, prealloc, start, end, bits); | |
658 | prealloc = NULL; | |
659 | BUG_ON(err == -EEXIST); | |
660 | goto out; | |
661 | } | |
662 | ||
663 | state = rb_entry(node, struct extent_state, rb_node); | |
664 | last_start = state->start; | |
665 | last_end = state->end; | |
666 | ||
667 | /* | |
668 | * | ---- desired range ---- | | |
669 | * | state | | |
670 | * | |
671 | * Just lock what we found and keep going | |
672 | */ | |
673 | if (state->start == start && state->end <= end) { | |
674 | set = state->state & bits; | |
675 | if (set && exclusive) { | |
676 | *failed_start = state->start; | |
677 | err = -EEXIST; | |
678 | goto out; | |
679 | } | |
680 | state->state |= bits; | |
681 | start = state->end + 1; | |
682 | merge_state(tree, state); | |
683 | goto search_again; | |
684 | } | |
685 | ||
686 | /* | |
687 | * | ---- desired range ---- | | |
688 | * | state | | |
689 | * or | |
690 | * | ------------- state -------------- | | |
691 | * | |
692 | * We need to split the extent we found, and may flip bits on | |
693 | * second half. | |
694 | * | |
695 | * If the extent we found extends past our | |
696 | * range, we just split and search again. It'll get split | |
697 | * again the next time though. | |
698 | * | |
699 | * If the extent we found is inside our range, we set the | |
700 | * desired bit on it. | |
701 | */ | |
702 | if (state->start < start) { | |
703 | set = state->state & bits; | |
704 | if (exclusive && set) { | |
705 | *failed_start = start; | |
706 | err = -EEXIST; | |
707 | goto out; | |
708 | } | |
709 | err = split_state(tree, state, prealloc, start); | |
710 | BUG_ON(err == -EEXIST); | |
711 | prealloc = NULL; | |
712 | if (err) | |
713 | goto out; | |
714 | if (state->end <= end) { | |
715 | state->state |= bits; | |
716 | start = state->end + 1; | |
717 | merge_state(tree, state); | |
718 | } else { | |
719 | start = state->start; | |
720 | } | |
721 | goto search_again; | |
722 | } | |
723 | /* | |
724 | * | ---- desired range ---- | | |
725 | * | state | | |
726 | * We need to split the extent, and set the bit | |
727 | * on the first half | |
728 | */ | |
729 | if (state->start <= end && state->end > end) { | |
730 | set = state->state & bits; | |
731 | if (exclusive && set) { | |
732 | *failed_start = start; | |
733 | err = -EEXIST; | |
734 | goto out; | |
735 | } | |
736 | err = split_state(tree, state, prealloc, end + 1); | |
737 | BUG_ON(err == -EEXIST); | |
738 | ||
739 | prealloc->state |= bits; | |
740 | merge_state(tree, prealloc); | |
741 | prealloc = NULL; | |
742 | goto out; | |
743 | } | |
744 | ||
745 | /* | |
746 | * | ---- desired range ---- | | |
747 | * | state | or | state | | |
748 | * | |
749 | * There's a hole, we need to insert something in it and | |
750 | * ignore the extent we found. | |
751 | */ | |
752 | if (state->start > start) { | |
753 | u64 this_end; | |
754 | if (end < last_start) | |
755 | this_end = end; | |
756 | else | |
757 | this_end = last_start -1; | |
758 | err = insert_state(tree, prealloc, start, this_end, | |
759 | bits); | |
760 | prealloc = NULL; | |
761 | BUG_ON(err == -EEXIST); | |
762 | if (err) | |
763 | goto out; | |
764 | start = this_end + 1; | |
765 | goto search_again; | |
766 | } | |
767 | goto search_again; | |
768 | ||
769 | out: | |
770 | write_unlock_irq(&tree->lock); | |
771 | if (prealloc) | |
772 | free_extent_state(prealloc); | |
773 | ||
774 | return err; | |
775 | ||
776 | search_again: | |
777 | if (start > end) | |
778 | goto out; | |
779 | write_unlock_irq(&tree->lock); | |
780 | if (mask & __GFP_WAIT) | |
781 | cond_resched(); | |
782 | goto again; | |
783 | } | |
784 | EXPORT_SYMBOL(set_extent_bit); | |
785 | ||
786 | /* wrappers around set/clear extent bit */ | |
787 | int set_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end, | |
788 | gfp_t mask) | |
789 | { | |
790 | return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL, | |
791 | mask); | |
792 | } | |
793 | EXPORT_SYMBOL(set_extent_dirty); | |
794 | ||
795 | int clear_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end, | |
796 | gfp_t mask) | |
797 | { | |
798 | return clear_extent_bit(tree, start, end, EXTENT_DIRTY, 0, 0, mask); | |
799 | } | |
800 | EXPORT_SYMBOL(clear_extent_dirty); | |
801 | ||
802 | int set_extent_new(struct extent_map_tree *tree, u64 start, u64 end, | |
803 | gfp_t mask) | |
804 | { | |
805 | return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL, | |
806 | mask); | |
807 | } | |
808 | EXPORT_SYMBOL(set_extent_new); | |
809 | ||
810 | int clear_extent_new(struct extent_map_tree *tree, u64 start, u64 end, | |
811 | gfp_t mask) | |
812 | { | |
813 | return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask); | |
814 | } | |
815 | EXPORT_SYMBOL(clear_extent_new); | |
816 | ||
817 | int set_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end, | |
818 | gfp_t mask) | |
819 | { | |
820 | return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL, | |
821 | mask); | |
822 | } | |
823 | EXPORT_SYMBOL(set_extent_uptodate); | |
824 | ||
825 | int clear_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end, | |
826 | gfp_t mask) | |
827 | { | |
828 | return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask); | |
829 | } | |
830 | EXPORT_SYMBOL(clear_extent_uptodate); | |
831 | ||
832 | int set_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end, | |
833 | gfp_t mask) | |
834 | { | |
835 | return set_extent_bit(tree, start, end, EXTENT_WRITEBACK, | |
836 | 0, NULL, mask); | |
837 | } | |
838 | EXPORT_SYMBOL(set_extent_writeback); | |
839 | ||
840 | int clear_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end, | |
841 | gfp_t mask) | |
842 | { | |
843 | return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask); | |
844 | } | |
845 | EXPORT_SYMBOL(clear_extent_writeback); | |
846 | ||
847 | int wait_on_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end) | |
848 | { | |
849 | return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK); | |
850 | } | |
851 | EXPORT_SYMBOL(wait_on_extent_writeback); | |
852 | ||
853 | /* | |
854 | * locks a range in ascending order, waiting for any locked regions | |
855 | * it hits on the way. [start,end] are inclusive, and this will sleep. | |
856 | */ | |
857 | int lock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask) | |
858 | { | |
859 | int err; | |
860 | u64 failed_start; | |
861 | while (1) { | |
862 | err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1, | |
863 | &failed_start, mask); | |
864 | if (err == -EEXIST && (mask & __GFP_WAIT)) { | |
865 | wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED); | |
866 | start = failed_start; | |
867 | } else { | |
868 | break; | |
869 | } | |
870 | WARN_ON(start > end); | |
871 | } | |
872 | return err; | |
873 | } | |
874 | EXPORT_SYMBOL(lock_extent); | |
875 | ||
876 | int unlock_extent(struct extent_map_tree *tree, u64 start, u64 end, | |
877 | gfp_t mask) | |
878 | { | |
879 | return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask); | |
880 | } | |
881 | EXPORT_SYMBOL(unlock_extent); | |
882 | ||
883 | /* | |
884 | * helper function to set pages and extents in the tree dirty | |
885 | */ | |
886 | int set_range_dirty(struct extent_map_tree *tree, u64 start, u64 end) | |
887 | { | |
888 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
889 | unsigned long end_index = end >> PAGE_CACHE_SHIFT; | |
890 | struct page *page; | |
891 | ||
892 | while (index <= end_index) { | |
893 | page = find_get_page(tree->mapping, index); | |
894 | BUG_ON(!page); | |
895 | __set_page_dirty_nobuffers(page); | |
896 | page_cache_release(page); | |
897 | index++; | |
898 | } | |
899 | set_extent_dirty(tree, start, end, GFP_NOFS); | |
900 | return 0; | |
901 | } | |
902 | EXPORT_SYMBOL(set_range_dirty); | |
903 | ||
904 | /* | |
905 | * helper function to set both pages and extents in the tree writeback | |
906 | */ | |
907 | int set_range_writeback(struct extent_map_tree *tree, u64 start, u64 end) | |
908 | { | |
909 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
910 | unsigned long end_index = end >> PAGE_CACHE_SHIFT; | |
911 | struct page *page; | |
912 | ||
913 | while (index <= end_index) { | |
914 | page = find_get_page(tree->mapping, index); | |
915 | BUG_ON(!page); | |
916 | set_page_writeback(page); | |
917 | page_cache_release(page); | |
918 | index++; | |
919 | } | |
920 | set_extent_writeback(tree, start, end, GFP_NOFS); | |
921 | return 0; | |
922 | } | |
923 | EXPORT_SYMBOL(set_range_writeback); | |
924 | ||
925 | /* | |
926 | * helper function to lock both pages and extents in the tree. | |
927 | * pages must be locked first. | |
928 | */ | |
929 | int lock_range(struct extent_map_tree *tree, u64 start, u64 end) | |
930 | { | |
931 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
932 | unsigned long end_index = end >> PAGE_CACHE_SHIFT; | |
933 | struct page *page; | |
934 | int err; | |
935 | ||
936 | while (index <= end_index) { | |
937 | page = grab_cache_page(tree->mapping, index); | |
938 | if (!page) { | |
939 | err = -ENOMEM; | |
940 | goto failed; | |
941 | } | |
942 | if (IS_ERR(page)) { | |
943 | err = PTR_ERR(page); | |
944 | goto failed; | |
945 | } | |
946 | index++; | |
947 | } | |
948 | lock_extent(tree, start, end, GFP_NOFS); | |
949 | return 0; | |
950 | ||
951 | failed: | |
952 | /* | |
953 | * we failed above in getting the page at 'index', so we undo here | |
954 | * up to but not including the page at 'index' | |
955 | */ | |
956 | end_index = index; | |
957 | index = start >> PAGE_CACHE_SHIFT; | |
958 | while (index < end_index) { | |
959 | page = find_get_page(tree->mapping, index); | |
960 | unlock_page(page); | |
961 | page_cache_release(page); | |
962 | index++; | |
963 | } | |
964 | return err; | |
965 | } | |
966 | EXPORT_SYMBOL(lock_range); | |
967 | ||
968 | /* | |
969 | * helper function to unlock both pages and extents in the tree. | |
970 | */ | |
971 | int unlock_range(struct extent_map_tree *tree, u64 start, u64 end) | |
972 | { | |
973 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
974 | unsigned long end_index = end >> PAGE_CACHE_SHIFT; | |
975 | struct page *page; | |
976 | ||
977 | while (index <= end_index) { | |
978 | page = find_get_page(tree->mapping, index); | |
979 | unlock_page(page); | |
980 | page_cache_release(page); | |
981 | index++; | |
982 | } | |
983 | unlock_extent(tree, start, end, GFP_NOFS); | |
984 | return 0; | |
985 | } | |
986 | EXPORT_SYMBOL(unlock_range); | |
987 | ||
988 | /* | |
989 | * searches a range in the state tree for a given mask. | |
990 | * If 'filled' == 1, this returns 1 only if ever extent in the tree | |
991 | * has the bits set. Otherwise, 1 is returned if any bit in the | |
992 | * range is found set. | |
993 | */ | |
994 | static int test_range_bit(struct extent_map_tree *tree, u64 start, u64 end, | |
995 | int bits, int filled) | |
996 | { | |
997 | struct extent_state *state = NULL; | |
998 | struct rb_node *node; | |
999 | int bitset = 0; | |
1000 | ||
1001 | read_lock_irq(&tree->lock); | |
1002 | node = tree_search(&tree->state, start); | |
1003 | while (node && start <= end) { | |
1004 | state = rb_entry(node, struct extent_state, rb_node); | |
1005 | if (state->start > end) | |
1006 | break; | |
1007 | ||
1008 | if (filled && state->start > start) { | |
1009 | bitset = 0; | |
1010 | break; | |
1011 | } | |
1012 | if (state->state & bits) { | |
1013 | bitset = 1; | |
1014 | if (!filled) | |
1015 | break; | |
1016 | } else if (filled) { | |
1017 | bitset = 0; | |
1018 | break; | |
1019 | } | |
1020 | start = state->end + 1; | |
1021 | if (start > end) | |
1022 | break; | |
1023 | node = rb_next(node); | |
1024 | } | |
1025 | read_unlock_irq(&tree->lock); | |
1026 | return bitset; | |
1027 | } | |
1028 | ||
1029 | /* | |
1030 | * helper function to set a given page up to date if all the | |
1031 | * extents in the tree for that page are up to date | |
1032 | */ | |
1033 | static int check_page_uptodate(struct extent_map_tree *tree, | |
1034 | struct page *page) | |
1035 | { | |
1036 | u64 start = page->index << PAGE_CACHE_SHIFT; | |
1037 | u64 end = start + PAGE_CACHE_SIZE - 1; | |
1038 | if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1)) | |
1039 | SetPageUptodate(page); | |
1040 | return 0; | |
1041 | } | |
1042 | ||
1043 | /* | |
1044 | * helper function to unlock a page if all the extents in the tree | |
1045 | * for that page are unlocked | |
1046 | */ | |
1047 | static int check_page_locked(struct extent_map_tree *tree, | |
1048 | struct page *page) | |
1049 | { | |
1050 | u64 start = page->index << PAGE_CACHE_SHIFT; | |
1051 | u64 end = start + PAGE_CACHE_SIZE - 1; | |
1052 | if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0)) | |
1053 | unlock_page(page); | |
1054 | return 0; | |
1055 | } | |
1056 | ||
1057 | /* | |
1058 | * helper function to end page writeback if all the extents | |
1059 | * in the tree for that page are done with writeback | |
1060 | */ | |
1061 | static int check_page_writeback(struct extent_map_tree *tree, | |
1062 | struct page *page) | |
1063 | { | |
1064 | u64 start = page->index << PAGE_CACHE_SHIFT; | |
1065 | u64 end = start + PAGE_CACHE_SIZE - 1; | |
1066 | if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0)) | |
1067 | end_page_writeback(page); | |
1068 | return 0; | |
1069 | } | |
1070 | ||
1071 | /* lots and lots of room for performance fixes in the end_bio funcs */ | |
1072 | ||
1073 | /* | |
1074 | * after a writepage IO is done, we need to: | |
1075 | * clear the uptodate bits on error | |
1076 | * clear the writeback bits in the extent tree for this IO | |
1077 | * end_page_writeback if the page has no more pending IO | |
1078 | * | |
1079 | * Scheduling is not allowed, so the extent state tree is expected | |
1080 | * to have one and only one object corresponding to this IO. | |
1081 | */ | |
1082 | static int end_bio_extent_writepage(struct bio *bio, | |
1083 | unsigned int bytes_done, int err) | |
1084 | { | |
1085 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
1086 | struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; | |
1087 | struct extent_map_tree *tree = bio->bi_private; | |
1088 | u64 start; | |
1089 | u64 end; | |
1090 | int whole_page; | |
1091 | ||
1092 | if (bio->bi_size) | |
1093 | return 1; | |
1094 | ||
1095 | do { | |
1096 | struct page *page = bvec->bv_page; | |
1097 | start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset; | |
1098 | end = start + bvec->bv_len - 1; | |
1099 | ||
1100 | if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE) | |
1101 | whole_page = 1; | |
1102 | else | |
1103 | whole_page = 0; | |
1104 | ||
1105 | if (--bvec >= bio->bi_io_vec) | |
1106 | prefetchw(&bvec->bv_page->flags); | |
1107 | ||
1108 | if (!uptodate) { | |
1109 | clear_extent_uptodate(tree, start, end, GFP_ATOMIC); | |
1110 | ClearPageUptodate(page); | |
1111 | SetPageError(page); | |
1112 | } | |
1113 | clear_extent_writeback(tree, start, end, GFP_ATOMIC); | |
1114 | ||
1115 | if (whole_page) | |
1116 | end_page_writeback(page); | |
1117 | else | |
1118 | check_page_writeback(tree, page); | |
1119 | } while (bvec >= bio->bi_io_vec); | |
1120 | ||
1121 | bio_put(bio); | |
1122 | return 0; | |
1123 | } | |
1124 | ||
1125 | /* | |
1126 | * after a readpage IO is done, we need to: | |
1127 | * clear the uptodate bits on error | |
1128 | * set the uptodate bits if things worked | |
1129 | * set the page up to date if all extents in the tree are uptodate | |
1130 | * clear the lock bit in the extent tree | |
1131 | * unlock the page if there are no other extents locked for it | |
1132 | * | |
1133 | * Scheduling is not allowed, so the extent state tree is expected | |
1134 | * to have one and only one object corresponding to this IO. | |
1135 | */ | |
1136 | static int end_bio_extent_readpage(struct bio *bio, | |
1137 | unsigned int bytes_done, int err) | |
1138 | { | |
1139 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
1140 | struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; | |
1141 | struct extent_map_tree *tree = bio->bi_private; | |
1142 | u64 start; | |
1143 | u64 end; | |
1144 | int whole_page; | |
1145 | ||
1146 | if (bio->bi_size) | |
1147 | return 1; | |
1148 | ||
1149 | do { | |
1150 | struct page *page = bvec->bv_page; | |
1151 | start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset; | |
1152 | end = start + bvec->bv_len - 1; | |
1153 | ||
1154 | if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE) | |
1155 | whole_page = 1; | |
1156 | else | |
1157 | whole_page = 0; | |
1158 | ||
1159 | if (--bvec >= bio->bi_io_vec) | |
1160 | prefetchw(&bvec->bv_page->flags); | |
1161 | ||
1162 | if (uptodate) { | |
1163 | set_extent_uptodate(tree, start, end, GFP_ATOMIC); | |
1164 | if (whole_page) | |
1165 | SetPageUptodate(page); | |
1166 | else | |
1167 | check_page_uptodate(tree, page); | |
1168 | } else { | |
1169 | ClearPageUptodate(page); | |
1170 | SetPageError(page); | |
1171 | } | |
1172 | ||
1173 | unlock_extent(tree, start, end, GFP_ATOMIC); | |
1174 | ||
1175 | if (whole_page) | |
1176 | unlock_page(page); | |
1177 | else | |
1178 | check_page_locked(tree, page); | |
1179 | } while (bvec >= bio->bi_io_vec); | |
1180 | ||
1181 | bio_put(bio); | |
1182 | return 0; | |
1183 | } | |
1184 | ||
1185 | /* | |
1186 | * IO done from prepare_write is pretty simple, we just unlock | |
1187 | * the structs in the extent tree when done, and set the uptodate bits | |
1188 | * as appropriate. | |
1189 | */ | |
1190 | static int end_bio_extent_preparewrite(struct bio *bio, | |
1191 | unsigned int bytes_done, int err) | |
1192 | { | |
1193 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
1194 | struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; | |
1195 | struct extent_map_tree *tree = bio->bi_private; | |
1196 | u64 start; | |
1197 | u64 end; | |
1198 | ||
1199 | if (bio->bi_size) | |
1200 | return 1; | |
1201 | ||
1202 | do { | |
1203 | struct page *page = bvec->bv_page; | |
1204 | start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset; | |
1205 | end = start + bvec->bv_len - 1; | |
1206 | ||
1207 | if (--bvec >= bio->bi_io_vec) | |
1208 | prefetchw(&bvec->bv_page->flags); | |
1209 | ||
1210 | if (uptodate) { | |
1211 | set_extent_uptodate(tree, start, end, GFP_ATOMIC); | |
1212 | } else { | |
1213 | ClearPageUptodate(page); | |
1214 | SetPageError(page); | |
1215 | } | |
1216 | ||
1217 | unlock_extent(tree, start, end, GFP_ATOMIC); | |
1218 | ||
1219 | } while (bvec >= bio->bi_io_vec); | |
1220 | ||
1221 | bio_put(bio); | |
1222 | return 0; | |
1223 | } | |
1224 | ||
1225 | static int submit_extent_page(int rw, struct extent_map_tree *tree, | |
1226 | struct page *page, sector_t sector, | |
1227 | size_t size, unsigned long offset, | |
1228 | struct block_device *bdev, | |
1229 | bio_end_io_t end_io_func) | |
1230 | { | |
1231 | struct bio *bio; | |
1232 | int ret = 0; | |
1233 | ||
1234 | bio = bio_alloc(GFP_NOIO, 1); | |
1235 | ||
1236 | bio->bi_sector = sector; | |
1237 | bio->bi_bdev = bdev; | |
1238 | bio->bi_io_vec[0].bv_page = page; | |
1239 | bio->bi_io_vec[0].bv_len = size; | |
1240 | bio->bi_io_vec[0].bv_offset = offset; | |
1241 | ||
1242 | bio->bi_vcnt = 1; | |
1243 | bio->bi_idx = 0; | |
1244 | bio->bi_size = size; | |
1245 | ||
1246 | bio->bi_end_io = end_io_func; | |
1247 | bio->bi_private = tree; | |
1248 | ||
1249 | bio_get(bio); | |
1250 | submit_bio(rw, bio); | |
1251 | ||
1252 | if (bio_flagged(bio, BIO_EOPNOTSUPP)) | |
1253 | ret = -EOPNOTSUPP; | |
1254 | ||
1255 | bio_put(bio); | |
1256 | return ret; | |
1257 | } | |
1258 | ||
1259 | /* | |
1260 | * basic readpage implementation. Locked extent state structs are inserted | |
1261 | * into the tree that are removed when the IO is done (by the end_io | |
1262 | * handlers) | |
1263 | */ | |
1264 | int extent_read_full_page(struct extent_map_tree *tree, struct page *page, | |
1265 | get_extent_t *get_extent) | |
1266 | { | |
1267 | struct inode *inode = page->mapping->host; | |
1268 | u64 start = page->index << PAGE_CACHE_SHIFT; | |
1269 | u64 page_end = start + PAGE_CACHE_SIZE - 1; | |
1270 | u64 end; | |
1271 | u64 cur = start; | |
1272 | u64 extent_offset; | |
1273 | u64 last_byte = i_size_read(inode); | |
1274 | u64 block_start; | |
1275 | u64 cur_end; | |
1276 | sector_t sector; | |
1277 | struct extent_map *em; | |
1278 | struct block_device *bdev; | |
1279 | int ret; | |
1280 | int nr = 0; | |
1281 | size_t page_offset = 0; | |
1282 | size_t iosize; | |
1283 | size_t blocksize = inode->i_sb->s_blocksize; | |
1284 | ||
1285 | if (!PagePrivate(page)) { | |
1286 | SetPagePrivate(page); | |
1287 | set_page_private(page, 1); | |
1288 | page_cache_get(page); | |
1289 | } | |
1290 | ||
1291 | end = page_end; | |
1292 | lock_extent(tree, start, end, GFP_NOFS); | |
1293 | ||
1294 | while (cur <= end) { | |
1295 | if (cur >= last_byte) { | |
1296 | iosize = PAGE_CACHE_SIZE - page_offset; | |
1297 | zero_user_page(page, page_offset, iosize, KM_USER0); | |
1298 | set_extent_uptodate(tree, cur, cur + iosize - 1, | |
1299 | GFP_NOFS); | |
1300 | unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS); | |
1301 | break; | |
1302 | } | |
1303 | em = get_extent(inode, page, page_offset, cur, end, 0); | |
1304 | if (IS_ERR(em) || !em) { | |
1305 | SetPageError(page); | |
1306 | unlock_extent(tree, cur, end, GFP_NOFS); | |
1307 | break; | |
1308 | } | |
1309 | ||
1310 | extent_offset = cur - em->start; | |
1311 | BUG_ON(em->end < cur); | |
1312 | BUG_ON(end < cur); | |
1313 | ||
1314 | iosize = min(em->end - cur, end - cur) + 1; | |
1315 | cur_end = min(em->end, end); | |
1316 | iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1); | |
1317 | sector = (em->block_start + extent_offset) >> 9; | |
1318 | bdev = em->bdev; | |
1319 | block_start = em->block_start; | |
1320 | free_extent_map(em); | |
1321 | em = NULL; | |
1322 | ||
1323 | /* we've found a hole, just zero and go on */ | |
1324 | if (block_start == 0) { | |
1325 | zero_user_page(page, page_offset, iosize, KM_USER0); | |
1326 | set_extent_uptodate(tree, cur, cur + iosize - 1, | |
1327 | GFP_NOFS); | |
1328 | unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS); | |
1329 | cur = cur + iosize; | |
1330 | page_offset += iosize; | |
1331 | continue; | |
1332 | } | |
1333 | /* the get_extent function already copied into the page */ | |
1334 | if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) { | |
1335 | unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS); | |
1336 | cur = cur + iosize; | |
1337 | page_offset += iosize; | |
1338 | continue; | |
1339 | } | |
1340 | ||
1341 | ret = submit_extent_page(READ, tree, page, | |
1342 | sector, iosize, page_offset, bdev, | |
1343 | end_bio_extent_readpage); | |
1344 | if (ret) | |
1345 | SetPageError(page); | |
1346 | cur = cur + iosize; | |
1347 | page_offset += iosize; | |
1348 | nr++; | |
1349 | } | |
1350 | if (!nr) { | |
1351 | if (!PageError(page)) | |
1352 | SetPageUptodate(page); | |
1353 | unlock_page(page); | |
1354 | } | |
1355 | return 0; | |
1356 | } | |
1357 | EXPORT_SYMBOL(extent_read_full_page); | |
1358 | ||
1359 | /* | |
1360 | * the writepage semantics are similar to regular writepage. extent | |
1361 | * records are inserted to lock ranges in the tree, and as dirty areas | |
1362 | * are found, they are marked writeback. Then the lock bits are removed | |
1363 | * and the end_io handler clears the writeback ranges | |
1364 | */ | |
1365 | int extent_write_full_page(struct extent_map_tree *tree, struct page *page, | |
1366 | get_extent_t *get_extent, | |
1367 | struct writeback_control *wbc) | |
1368 | { | |
1369 | struct inode *inode = page->mapping->host; | |
1370 | u64 start = page->index << PAGE_CACHE_SHIFT; | |
1371 | u64 page_end = start + PAGE_CACHE_SIZE - 1; | |
1372 | u64 end; | |
1373 | u64 cur = start; | |
1374 | u64 extent_offset; | |
1375 | u64 last_byte = i_size_read(inode); | |
1376 | u64 block_start; | |
1377 | sector_t sector; | |
1378 | struct extent_map *em; | |
1379 | struct block_device *bdev; | |
1380 | int ret; | |
1381 | int nr = 0; | |
1382 | size_t page_offset = 0; | |
1383 | size_t iosize; | |
1384 | size_t blocksize; | |
1385 | loff_t i_size = i_size_read(inode); | |
1386 | unsigned long end_index = i_size >> PAGE_CACHE_SHIFT; | |
1387 | ||
1388 | if (page->index > end_index) { | |
1389 | clear_extent_dirty(tree, start, page_end, GFP_NOFS); | |
1390 | unlock_page(page); | |
1391 | return 0; | |
1392 | } | |
1393 | ||
1394 | if (page->index == end_index) { | |
1395 | size_t offset = i_size & (PAGE_CACHE_SIZE - 1); | |
1396 | zero_user_page(page, offset, | |
1397 | PAGE_CACHE_SIZE - offset, KM_USER0); | |
1398 | } | |
1399 | ||
1400 | if (!PagePrivate(page)) { | |
1401 | SetPagePrivate(page); | |
1402 | set_page_private(page, 1); | |
1403 | page_cache_get(page); | |
1404 | } | |
1405 | ||
1406 | end = page_end; | |
1407 | lock_extent(tree, start, page_end, GFP_NOFS); | |
1408 | ||
1409 | if (last_byte <= start) { | |
1410 | clear_extent_dirty(tree, start, page_end, GFP_NOFS); | |
1411 | goto done; | |
1412 | } | |
1413 | ||
1414 | set_extent_uptodate(tree, start, page_end, GFP_NOFS); | |
1415 | blocksize = inode->i_sb->s_blocksize; | |
1416 | ||
1417 | while (cur <= end) { | |
1418 | if (cur >= last_byte) { | |
1419 | clear_extent_dirty(tree, cur, page_end, GFP_NOFS); | |
1420 | break; | |
1421 | } | |
1422 | em = get_extent(inode, page, page_offset, cur, end, 1); | |
1423 | if (IS_ERR(em) || !em) { | |
1424 | SetPageError(page); | |
1425 | break; | |
1426 | } | |
1427 | ||
1428 | extent_offset = cur - em->start; | |
1429 | BUG_ON(em->end < cur); | |
1430 | BUG_ON(end < cur); | |
1431 | iosize = min(em->end - cur, end - cur) + 1; | |
1432 | iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1); | |
1433 | sector = (em->block_start + extent_offset) >> 9; | |
1434 | bdev = em->bdev; | |
1435 | block_start = em->block_start; | |
1436 | free_extent_map(em); | |
1437 | em = NULL; | |
1438 | ||
1439 | if (block_start == 0 || block_start == EXTENT_MAP_INLINE) { | |
1440 | clear_extent_dirty(tree, cur, | |
1441 | cur + iosize - 1, GFP_NOFS); | |
1442 | cur = cur + iosize; | |
1443 | page_offset += iosize; | |
1444 | continue; | |
1445 | } | |
1446 | ||
1447 | /* leave this out until we have a page_mkwrite call */ | |
1448 | if (0 && !test_range_bit(tree, cur, cur + iosize - 1, | |
1449 | EXTENT_DIRTY, 0)) { | |
1450 | cur = cur + iosize; | |
1451 | page_offset += iosize; | |
1452 | continue; | |
1453 | } | |
1454 | clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS); | |
1455 | set_range_writeback(tree, cur, cur + iosize - 1); | |
1456 | ret = submit_extent_page(WRITE, tree, page, | |
1457 | sector, iosize, page_offset, bdev, | |
1458 | end_bio_extent_writepage); | |
1459 | if (ret) | |
1460 | SetPageError(page); | |
1461 | cur = cur + iosize; | |
1462 | page_offset += iosize; | |
1463 | nr++; | |
1464 | } | |
1465 | done: | |
1466 | WARN_ON(test_range_bit(tree, start, page_end, EXTENT_DIRTY, 0)); | |
1467 | unlock_extent(tree, start, page_end, GFP_NOFS); | |
1468 | unlock_page(page); | |
1469 | return 0; | |
1470 | } | |
1471 | EXPORT_SYMBOL(extent_write_full_page); | |
1472 | ||
1473 | /* | |
1474 | * basic invalidatepage code, this waits on any locked or writeback | |
1475 | * ranges corresponding to the page, and then deletes any extent state | |
1476 | * records from the tree | |
1477 | */ | |
1478 | int extent_invalidatepage(struct extent_map_tree *tree, | |
1479 | struct page *page, unsigned long offset) | |
1480 | { | |
1481 | u64 start = (page->index << PAGE_CACHE_SHIFT); | |
1482 | u64 end = start + PAGE_CACHE_SIZE - 1; | |
1483 | size_t blocksize = page->mapping->host->i_sb->s_blocksize; | |
1484 | ||
1485 | start += (offset + blocksize -1) & ~(blocksize - 1); | |
1486 | if (start > end) | |
1487 | return 0; | |
1488 | ||
1489 | lock_extent(tree, start, end, GFP_NOFS); | |
1490 | wait_on_extent_writeback(tree, start, end); | |
1491 | clear_extent_bit(tree, start, end, EXTENT_LOCKED | EXTENT_DIRTY, | |
1492 | 1, 1, GFP_NOFS); | |
1493 | return 0; | |
1494 | } | |
1495 | EXPORT_SYMBOL(extent_invalidatepage); | |
1496 | ||
1497 | /* | |
1498 | * simple commit_write call, set_range_dirty is used to mark both | |
1499 | * the pages and the extent records as dirty | |
1500 | */ | |
1501 | int extent_commit_write(struct extent_map_tree *tree, | |
1502 | struct inode *inode, struct page *page, | |
1503 | unsigned from, unsigned to) | |
1504 | { | |
1505 | loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; | |
1506 | ||
1507 | if (!PagePrivate(page)) { | |
1508 | SetPagePrivate(page); | |
1509 | set_page_private(page, 1); | |
1510 | page_cache_get(page); | |
1511 | } | |
1512 | ||
1513 | set_page_dirty(page); | |
1514 | ||
1515 | if (pos > inode->i_size) { | |
1516 | i_size_write(inode, pos); | |
1517 | mark_inode_dirty(inode); | |
1518 | } | |
1519 | return 0; | |
1520 | } | |
1521 | EXPORT_SYMBOL(extent_commit_write); | |
1522 | ||
1523 | int extent_prepare_write(struct extent_map_tree *tree, | |
1524 | struct inode *inode, struct page *page, | |
1525 | unsigned from, unsigned to, get_extent_t *get_extent) | |
1526 | { | |
1527 | u64 page_start = page->index << PAGE_CACHE_SHIFT; | |
1528 | u64 page_end = page_start + PAGE_CACHE_SIZE - 1; | |
1529 | u64 block_start; | |
1530 | u64 orig_block_start; | |
1531 | u64 block_end; | |
1532 | u64 cur_end; | |
1533 | struct extent_map *em; | |
1534 | unsigned blocksize = 1 << inode->i_blkbits; | |
1535 | size_t page_offset = 0; | |
1536 | size_t block_off_start; | |
1537 | size_t block_off_end; | |
1538 | int err = 0; | |
1539 | int iocount = 0; | |
1540 | int ret = 0; | |
1541 | int isnew; | |
1542 | ||
1543 | if (!PagePrivate(page)) { | |
1544 | SetPagePrivate(page); | |
1545 | set_page_private(page, 1); | |
1546 | page_cache_get(page); | |
1547 | } | |
1548 | block_start = (page_start + from) & ~((u64)blocksize - 1); | |
1549 | block_end = (page_start + to - 1) | (blocksize - 1); | |
1550 | orig_block_start = block_start; | |
1551 | ||
1552 | lock_extent(tree, page_start, page_end, GFP_NOFS); | |
1553 | while(block_start <= block_end) { | |
1554 | em = get_extent(inode, page, page_offset, block_start, | |
1555 | block_end, 1); | |
1556 | if (IS_ERR(em) || !em) { | |
1557 | goto err; | |
1558 | } | |
1559 | cur_end = min(block_end, em->end); | |
1560 | block_off_start = block_start & (PAGE_CACHE_SIZE - 1); | |
1561 | block_off_end = block_off_start + blocksize; | |
1562 | isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS); | |
1563 | ||
1564 | if (!PageUptodate(page) && isnew && | |
1565 | (block_off_end > to || block_off_start < from)) { | |
1566 | void *kaddr; | |
1567 | ||
1568 | kaddr = kmap_atomic(page, KM_USER0); | |
1569 | if (block_off_end > to) | |
1570 | memset(kaddr + to, 0, block_off_end - to); | |
1571 | if (block_off_start < from) | |
1572 | memset(kaddr + block_off_start, 0, | |
1573 | from - block_off_start); | |
1574 | flush_dcache_page(page); | |
1575 | kunmap_atomic(kaddr, KM_USER0); | |
1576 | } | |
1577 | if (!isnew && !PageUptodate(page) && | |
1578 | (block_off_end > to || block_off_start < from) && | |
1579 | !test_range_bit(tree, block_start, cur_end, | |
1580 | EXTENT_UPTODATE, 1)) { | |
1581 | u64 sector; | |
1582 | u64 extent_offset = block_start - em->start; | |
1583 | size_t iosize; | |
1584 | sector = (em->block_start + extent_offset) >> 9; | |
1585 | iosize = (cur_end - block_start + blocksize - 1) & | |
1586 | ~((u64)blocksize - 1); | |
1587 | /* | |
1588 | * we've already got the extent locked, but we | |
1589 | * need to split the state such that our end_bio | |
1590 | * handler can clear the lock. | |
1591 | */ | |
1592 | set_extent_bit(tree, block_start, | |
1593 | block_start + iosize - 1, | |
1594 | EXTENT_LOCKED, 0, NULL, GFP_NOFS); | |
1595 | ret = submit_extent_page(READ, tree, page, | |
1596 | sector, iosize, page_offset, em->bdev, | |
1597 | end_bio_extent_preparewrite); | |
1598 | iocount++; | |
1599 | block_start = block_start + iosize; | |
1600 | } else { | |
1601 | set_extent_uptodate(tree, block_start, cur_end, | |
1602 | GFP_NOFS); | |
1603 | unlock_extent(tree, block_start, cur_end, GFP_NOFS); | |
1604 | block_start = cur_end + 1; | |
1605 | } | |
1606 | page_offset = block_start & (PAGE_CACHE_SIZE - 1); | |
1607 | free_extent_map(em); | |
1608 | } | |
1609 | if (iocount) { | |
1610 | wait_extent_bit(tree, orig_block_start, | |
1611 | block_end, EXTENT_LOCKED); | |
1612 | } | |
1613 | check_page_uptodate(tree, page); | |
1614 | err: | |
1615 | /* FIXME, zero out newly allocated blocks on error */ | |
1616 | return err; | |
1617 | } | |
1618 | EXPORT_SYMBOL(extent_prepare_write); | |
1619 | ||
1620 | /* | |
1621 | * a helper for releasepage. As long as there are no locked extents | |
1622 | * in the range corresponding to the page, both state records and extent | |
1623 | * map records are removed | |
1624 | */ | |
1625 | int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page) | |
1626 | { | |
1627 | struct extent_map *em; | |
1628 | u64 start = page->index << PAGE_CACHE_SHIFT; | |
1629 | u64 end = start + PAGE_CACHE_SIZE - 1; | |
1630 | u64 orig_start = start; | |
1631 | ||
1632 | while (start <= end) { | |
1633 | em = lookup_extent_mapping(tree, start, end); | |
1634 | if (!em || IS_ERR(em)) | |
1635 | break; | |
1636 | if (test_range_bit(tree, em->start, em->end, | |
1637 | EXTENT_LOCKED, 0)) { | |
1638 | free_extent_map(em); | |
1639 | start = em->end + 1; | |
1640 | printk("range still locked %Lu %Lu\n", em->start, em->end); | |
1641 | break; | |
1642 | } | |
1643 | remove_extent_mapping(tree, em); | |
1644 | start = em->end + 1; | |
1645 | /* once for the rb tree */ | |
1646 | free_extent_map(em); | |
1647 | /* once for us */ | |
1648 | free_extent_map(em); | |
1649 | } | |
1650 | WARN_ON(test_range_bit(tree, orig_start, end, EXTENT_WRITEBACK, 0)); | |
1651 | clear_extent_bit(tree, orig_start, end, EXTENT_UPTODATE, | |
1652 | 1, 1, GFP_NOFS); | |
1653 | return 1; | |
1654 | } | |
1655 | EXPORT_SYMBOL(try_release_extent_mapping); | |
1656 |