1 /* SPDX-License-Identifier: GPL-2.0 */
2 
3 #ifndef BTRFS_EXTENT_IO_H
4 #define BTRFS_EXTENT_IO_H
5 
6 #include <linux/rbtree.h>
7 #include <linux/refcount.h>
8 #include "ulist.h"
9 
10 /* bits for the extent state */
11 #define EXTENT_DIRTY		(1U << 0)
12 #define EXTENT_WRITEBACK	(1U << 1)
13 #define EXTENT_UPTODATE		(1U << 2)
14 #define EXTENT_LOCKED		(1U << 3)
15 #define EXTENT_NEW		(1U << 4)
16 #define EXTENT_DELALLOC		(1U << 5)
17 #define EXTENT_DEFRAG		(1U << 6)
18 #define EXTENT_BOUNDARY		(1U << 9)
19 #define EXTENT_NODATASUM	(1U << 10)
20 #define EXTENT_CLEAR_META_RESV	(1U << 11)
21 #define EXTENT_FIRST_DELALLOC	(1U << 12)
22 #define EXTENT_NEED_WAIT	(1U << 13)
23 #define EXTENT_DAMAGED		(1U << 14)
24 #define EXTENT_NORESERVE	(1U << 15)
25 #define EXTENT_QGROUP_RESERVED	(1U << 16)
26 #define EXTENT_CLEAR_DATA_RESV	(1U << 17)
27 #define EXTENT_DELALLOC_NEW	(1U << 18)
28 #define EXTENT_IOBITS		(EXTENT_LOCKED | EXTENT_WRITEBACK)
29 #define EXTENT_DO_ACCOUNTING    (EXTENT_CLEAR_META_RESV | \
30 				 EXTENT_CLEAR_DATA_RESV)
31 #define EXTENT_CTLBITS		(EXTENT_DO_ACCOUNTING | EXTENT_FIRST_DELALLOC)
32 
33 /*
34  * flags for bio submission. The high bits indicate the compression
35  * type for this bio
36  */
37 #define EXTENT_BIO_COMPRESSED 1
38 #define EXTENT_BIO_FLAG_SHIFT 16
39 
40 /* these are bit numbers for test/set bit */
41 #define EXTENT_BUFFER_UPTODATE 0
42 #define EXTENT_BUFFER_DIRTY 2
43 #define EXTENT_BUFFER_CORRUPT 3
44 #define EXTENT_BUFFER_READAHEAD 4	/* this got triggered by readahead */
45 #define EXTENT_BUFFER_TREE_REF 5
46 #define EXTENT_BUFFER_STALE 6
47 #define EXTENT_BUFFER_WRITEBACK 7
48 #define EXTENT_BUFFER_READ_ERR 8        /* read IO error */
49 #define EXTENT_BUFFER_UNMAPPED 9
50 #define EXTENT_BUFFER_IN_TREE 10
51 #define EXTENT_BUFFER_WRITE_ERR 11    /* write IO error */
52 
53 /* these are flags for __process_pages_contig */
54 #define PAGE_UNLOCK		(1 << 0)
55 #define PAGE_CLEAR_DIRTY	(1 << 1)
56 #define PAGE_SET_WRITEBACK	(1 << 2)
57 #define PAGE_END_WRITEBACK	(1 << 3)
58 #define PAGE_SET_PRIVATE2	(1 << 4)
59 #define PAGE_SET_ERROR		(1 << 5)
60 #define PAGE_LOCK		(1 << 6)
61 
62 /*
63  * page->private values.  Every page that is controlled by the extent
64  * map has page->private set to one.
65  */
66 #define EXTENT_PAGE_PRIVATE 1
67 
68 /*
69  * The extent buffer bitmap operations are done with byte granularity instead of
70  * word granularity for two reasons:
71  * 1. The bitmaps must be little-endian on disk.
72  * 2. Bitmap items are not guaranteed to be aligned to a word and therefore a
73  *    single word in a bitmap may straddle two pages in the extent buffer.
74  */
75 #define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
76 #define BYTE_MASK ((1 << BITS_PER_BYTE) - 1)
77 #define BITMAP_FIRST_BYTE_MASK(start) \
78 	((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
79 #define BITMAP_LAST_BYTE_MASK(nbits) \
80 	(BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))
81 
82 struct extent_state;
83 struct btrfs_root;
84 struct btrfs_inode;
85 struct btrfs_io_bio;
86 struct io_failure_record;
87 
88 typedef	blk_status_t (extent_submit_bio_hook_t)(void *private_data, struct bio *bio,
89 				       int mirror_num, unsigned long bio_flags,
90 				       u64 bio_offset);
91 
92 typedef blk_status_t (extent_submit_bio_start_t)(void *private_data,
93 		struct bio *bio, u64 bio_offset);
94 
95 struct extent_io_ops {
96 	/*
97 	 * The following callbacks must be allways defined, the function
98 	 * pointer will be called unconditionally.
99 	 */
100 	extent_submit_bio_hook_t *submit_bio_hook;
101 	int (*readpage_end_io_hook)(struct btrfs_io_bio *io_bio, u64 phy_offset,
102 				    struct page *page, u64 start, u64 end,
103 				    int mirror);
104 	int (*readpage_io_failed_hook)(struct page *page, int failed_mirror);
105 
106 	/*
107 	 * Optional hooks, called if the pointer is not NULL
108 	 */
109 	int (*writepage_start_hook)(struct page *page, u64 start, u64 end);
110 	void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end,
111 				      struct extent_state *state, int uptodate);
112 	void (*set_bit_hook)(void *private_data, struct extent_state *state,
113 			     unsigned *bits);
114 	void (*clear_bit_hook)(void *private_data,
115 			struct extent_state *state,
116 			unsigned *bits);
117 	void (*merge_extent_hook)(void *private_data,
118 				  struct extent_state *new,
119 				  struct extent_state *other);
120 	void (*split_extent_hook)(void *private_data,
121 				  struct extent_state *orig, u64 split);
122 	void (*check_extent_io_range)(void *private_data, const char *caller,
123 				      u64 start, u64 end);
124 };
125 
126 struct extent_io_tree {
127 	struct rb_root state;
128 	void *private_data;
129 	u64 dirty_bytes;
130 	int track_uptodate;
131 	spinlock_t lock;
132 	const struct extent_io_ops *ops;
133 };
134 
135 struct extent_state {
136 	u64 start;
137 	u64 end; /* inclusive */
138 	struct rb_node rb_node;
139 
140 	/* ADD NEW ELEMENTS AFTER THIS */
141 	wait_queue_head_t wq;
142 	refcount_t refs;
143 	unsigned state;
144 
145 	struct io_failure_record *failrec;
146 
147 #ifdef CONFIG_BTRFS_DEBUG
148 	struct list_head leak_list;
149 #endif
150 };
151 
152 #define INLINE_EXTENT_BUFFER_PAGES 16
153 #define MAX_INLINE_EXTENT_BUFFER_SIZE (INLINE_EXTENT_BUFFER_PAGES * PAGE_SIZE)
154 struct extent_buffer {
155 	u64 start;
156 	unsigned long len;
157 	unsigned long bflags;
158 	struct btrfs_fs_info *fs_info;
159 	spinlock_t refs_lock;
160 	atomic_t refs;
161 	atomic_t io_pages;
162 	int read_mirror;
163 	struct rcu_head rcu_head;
164 	pid_t lock_owner;
165 
166 	/* count of read lock holders on the extent buffer */
167 	atomic_t write_locks;
168 	atomic_t read_locks;
169 	atomic_t blocking_writers;
170 	atomic_t blocking_readers;
171 	atomic_t spinning_readers;
172 	atomic_t spinning_writers;
173 	short lock_nested;
174 	/* >= 0 if eb belongs to a log tree, -1 otherwise */
175 	short log_index;
176 
177 	/* protects write locks */
178 	rwlock_t lock;
179 
180 	/* readers use lock_wq while they wait for the write
181 	 * lock holders to unlock
182 	 */
183 	wait_queue_head_t write_lock_wq;
184 
185 	/* writers use read_lock_wq while they wait for readers
186 	 * to unlock
187 	 */
188 	wait_queue_head_t read_lock_wq;
189 	struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
190 #ifdef CONFIG_BTRFS_DEBUG
191 	struct list_head leak_list;
192 #endif
193 };
194 
195 /*
196  * Structure to record how many bytes and which ranges are set/cleared
197  */
198 struct extent_changeset {
199 	/* How many bytes are set/cleared in this operation */
200 	u64 bytes_changed;
201 
202 	/* Changed ranges */
203 	struct ulist range_changed;
204 };
205 
extent_changeset_init(struct extent_changeset * changeset)206 static inline void extent_changeset_init(struct extent_changeset *changeset)
207 {
208 	changeset->bytes_changed = 0;
209 	ulist_init(&changeset->range_changed);
210 }
211 
extent_changeset_alloc(void)212 static inline struct extent_changeset *extent_changeset_alloc(void)
213 {
214 	struct extent_changeset *ret;
215 
216 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
217 	if (!ret)
218 		return NULL;
219 
220 	extent_changeset_init(ret);
221 	return ret;
222 }
223 
extent_changeset_release(struct extent_changeset * changeset)224 static inline void extent_changeset_release(struct extent_changeset *changeset)
225 {
226 	if (!changeset)
227 		return;
228 	changeset->bytes_changed = 0;
229 	ulist_release(&changeset->range_changed);
230 }
231 
extent_changeset_free(struct extent_changeset * changeset)232 static inline void extent_changeset_free(struct extent_changeset *changeset)
233 {
234 	if (!changeset)
235 		return;
236 	extent_changeset_release(changeset);
237 	kfree(changeset);
238 }
239 
extent_set_compress_type(unsigned long * bio_flags,int compress_type)240 static inline void extent_set_compress_type(unsigned long *bio_flags,
241 					    int compress_type)
242 {
243 	*bio_flags |= compress_type << EXTENT_BIO_FLAG_SHIFT;
244 }
245 
extent_compress_type(unsigned long bio_flags)246 static inline int extent_compress_type(unsigned long bio_flags)
247 {
248 	return bio_flags >> EXTENT_BIO_FLAG_SHIFT;
249 }
250 
251 struct extent_map_tree;
252 
253 typedef struct extent_map *(get_extent_t)(struct btrfs_inode *inode,
254 					  struct page *page,
255 					  size_t pg_offset,
256 					  u64 start, u64 len,
257 					  int create);
258 
259 void extent_io_tree_init(struct extent_io_tree *tree, void *private_data);
260 int try_release_extent_mapping(struct page *page, gfp_t mask);
261 int try_release_extent_buffer(struct page *page);
262 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
263 		     struct extent_state **cached);
264 
lock_extent(struct extent_io_tree * tree,u64 start,u64 end)265 static inline int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
266 {
267 	return lock_extent_bits(tree, start, end, NULL);
268 }
269 
270 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end);
271 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
272 			  get_extent_t *get_extent, int mirror_num);
273 int __init extent_io_init(void);
274 void __cold extent_io_exit(void);
275 
276 u64 count_range_bits(struct extent_io_tree *tree,
277 		     u64 *start, u64 search_end,
278 		     u64 max_bytes, unsigned bits, int contig);
279 
280 void free_extent_state(struct extent_state *state);
281 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
282 		   unsigned bits, int filled,
283 		   struct extent_state *cached_state);
284 int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
285 		unsigned bits, struct extent_changeset *changeset);
286 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
287 		     unsigned bits, int wake, int delete,
288 		     struct extent_state **cached);
289 int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
290 		     unsigned bits, int wake, int delete,
291 		     struct extent_state **cached, gfp_t mask,
292 		     struct extent_changeset *changeset);
293 
unlock_extent(struct extent_io_tree * tree,u64 start,u64 end)294 static inline int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
295 {
296 	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL);
297 }
298 
unlock_extent_cached(struct extent_io_tree * tree,u64 start,u64 end,struct extent_state ** cached)299 static inline int unlock_extent_cached(struct extent_io_tree *tree, u64 start,
300 		u64 end, struct extent_state **cached)
301 {
302 	return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
303 				GFP_NOFS, NULL);
304 }
305 
unlock_extent_cached_atomic(struct extent_io_tree * tree,u64 start,u64 end,struct extent_state ** cached)306 static inline int unlock_extent_cached_atomic(struct extent_io_tree *tree,
307 		u64 start, u64 end, struct extent_state **cached)
308 {
309 	return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
310 				GFP_ATOMIC, NULL);
311 }
312 
clear_extent_bits(struct extent_io_tree * tree,u64 start,u64 end,unsigned bits)313 static inline int clear_extent_bits(struct extent_io_tree *tree, u64 start,
314 		u64 end, unsigned bits)
315 {
316 	int wake = 0;
317 
318 	if (bits & EXTENT_LOCKED)
319 		wake = 1;
320 
321 	return clear_extent_bit(tree, start, end, bits, wake, 0, NULL);
322 }
323 
324 int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
325 			   unsigned bits, struct extent_changeset *changeset);
326 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
327 		   unsigned bits, u64 *failed_start,
328 		   struct extent_state **cached_state, gfp_t mask);
329 
set_extent_bits(struct extent_io_tree * tree,u64 start,u64 end,unsigned bits)330 static inline int set_extent_bits(struct extent_io_tree *tree, u64 start,
331 		u64 end, unsigned bits)
332 {
333 	return set_extent_bit(tree, start, end, bits, NULL, NULL, GFP_NOFS);
334 }
335 
clear_extent_uptodate(struct extent_io_tree * tree,u64 start,u64 end,struct extent_state ** cached_state)336 static inline int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
337 		u64 end, struct extent_state **cached_state)
338 {
339 	return __clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
340 				cached_state, GFP_NOFS, NULL);
341 }
342 
set_extent_dirty(struct extent_io_tree * tree,u64 start,u64 end,gfp_t mask)343 static inline int set_extent_dirty(struct extent_io_tree *tree, u64 start,
344 		u64 end, gfp_t mask)
345 {
346 	return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
347 			      NULL, mask);
348 }
349 
clear_extent_dirty(struct extent_io_tree * tree,u64 start,u64 end,struct extent_state ** cached)350 static inline int clear_extent_dirty(struct extent_io_tree *tree, u64 start,
351 				     u64 end, struct extent_state **cached)
352 {
353 	return clear_extent_bit(tree, start, end,
354 				EXTENT_DIRTY | EXTENT_DELALLOC |
355 				EXTENT_DO_ACCOUNTING, 0, 0, cached);
356 }
357 
358 int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
359 		       unsigned bits, unsigned clear_bits,
360 		       struct extent_state **cached_state);
361 
set_extent_delalloc(struct extent_io_tree * tree,u64 start,u64 end,unsigned int extra_bits,struct extent_state ** cached_state)362 static inline int set_extent_delalloc(struct extent_io_tree *tree, u64 start,
363 				      u64 end, unsigned int extra_bits,
364 				      struct extent_state **cached_state)
365 {
366 	return set_extent_bit(tree, start, end,
367 			      EXTENT_DELALLOC | EXTENT_UPTODATE | extra_bits,
368 			      NULL, cached_state, GFP_NOFS);
369 }
370 
set_extent_defrag(struct extent_io_tree * tree,u64 start,u64 end,struct extent_state ** cached_state)371 static inline int set_extent_defrag(struct extent_io_tree *tree, u64 start,
372 		u64 end, struct extent_state **cached_state)
373 {
374 	return set_extent_bit(tree, start, end,
375 			      EXTENT_DELALLOC | EXTENT_UPTODATE | EXTENT_DEFRAG,
376 			      NULL, cached_state, GFP_NOFS);
377 }
378 
set_extent_new(struct extent_io_tree * tree,u64 start,u64 end)379 static inline int set_extent_new(struct extent_io_tree *tree, u64 start,
380 		u64 end)
381 {
382 	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL, NULL,
383 			GFP_NOFS);
384 }
385 
set_extent_uptodate(struct extent_io_tree * tree,u64 start,u64 end,struct extent_state ** cached_state,gfp_t mask)386 static inline int set_extent_uptodate(struct extent_io_tree *tree, u64 start,
387 		u64 end, struct extent_state **cached_state, gfp_t mask)
388 {
389 	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL,
390 			      cached_state, mask);
391 }
392 
393 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
394 			  u64 *start_ret, u64 *end_ret, unsigned bits,
395 			  struct extent_state **cached_state);
396 int extent_invalidatepage(struct extent_io_tree *tree,
397 			  struct page *page, unsigned long offset);
398 int extent_write_full_page(struct page *page, struct writeback_control *wbc);
399 int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
400 			      int mode);
401 int extent_writepages(struct address_space *mapping,
402 		      struct writeback_control *wbc);
403 int btree_write_cache_pages(struct address_space *mapping,
404 			    struct writeback_control *wbc);
405 int extent_readpages(struct address_space *mapping, struct list_head *pages,
406 		     unsigned nr_pages);
407 int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
408 		__u64 start, __u64 len);
409 void set_page_extent_mapped(struct page *page);
410 
411 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
412 					  u64 start);
413 struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
414 						  u64 start, unsigned long len);
415 struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
416 						u64 start);
417 struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src);
418 struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
419 					 u64 start);
420 void free_extent_buffer(struct extent_buffer *eb);
421 void free_extent_buffer_stale(struct extent_buffer *eb);
422 #define WAIT_NONE	0
423 #define WAIT_COMPLETE	1
424 #define WAIT_PAGE_LOCK	2
425 int read_extent_buffer_pages(struct extent_io_tree *tree,
426 			     struct extent_buffer *eb, int wait,
427 			     int mirror_num);
428 void wait_on_extent_buffer_writeback(struct extent_buffer *eb);
429 
num_extent_pages(const struct extent_buffer * eb)430 static inline int num_extent_pages(const struct extent_buffer *eb)
431 {
432 	return (round_up(eb->start + eb->len, PAGE_SIZE) >> PAGE_SHIFT) -
433 	       (eb->start >> PAGE_SHIFT);
434 }
435 
extent_buffer_get(struct extent_buffer * eb)436 static inline void extent_buffer_get(struct extent_buffer *eb)
437 {
438 	atomic_inc(&eb->refs);
439 }
440 
extent_buffer_uptodate(struct extent_buffer * eb)441 static inline int extent_buffer_uptodate(struct extent_buffer *eb)
442 {
443 	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
444 }
445 
446 int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
447 			 unsigned long start, unsigned long len);
448 void read_extent_buffer(const struct extent_buffer *eb, void *dst,
449 			unsigned long start,
450 			unsigned long len);
451 int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
452 				       void __user *dst, unsigned long start,
453 				       unsigned long len);
454 void write_extent_buffer_fsid(struct extent_buffer *eb, const void *src);
455 void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
456 		const void *src);
457 void write_extent_buffer(struct extent_buffer *eb, const void *src,
458 			 unsigned long start, unsigned long len);
459 void copy_extent_buffer_full(struct extent_buffer *dst,
460 			     struct extent_buffer *src);
461 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
462 			unsigned long dst_offset, unsigned long src_offset,
463 			unsigned long len);
464 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
465 			   unsigned long src_offset, unsigned long len);
466 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
467 			   unsigned long src_offset, unsigned long len);
468 void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
469 			   unsigned long len);
470 int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
471 			   unsigned long pos);
472 void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
473 			      unsigned long pos, unsigned long len);
474 void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
475 				unsigned long pos, unsigned long len);
476 void clear_extent_buffer_dirty(struct extent_buffer *eb);
477 int set_extent_buffer_dirty(struct extent_buffer *eb);
478 void set_extent_buffer_uptodate(struct extent_buffer *eb);
479 void clear_extent_buffer_uptodate(struct extent_buffer *eb);
480 int extent_buffer_under_io(struct extent_buffer *eb);
481 int map_private_extent_buffer(const struct extent_buffer *eb,
482 			      unsigned long offset, unsigned long min_len,
483 			      char **map, unsigned long *map_start,
484 			      unsigned long *map_len);
485 void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end);
486 void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end);
487 void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
488 				 u64 delalloc_end, struct page *locked_page,
489 				 unsigned bits_to_clear,
490 				 unsigned long page_ops);
491 struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_byte);
492 struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs);
493 struct bio *btrfs_bio_clone(struct bio *bio);
494 struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size);
495 
496 struct btrfs_fs_info;
497 struct btrfs_inode;
498 
499 int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
500 		      u64 length, u64 logical, struct page *page,
501 		      unsigned int pg_offset, int mirror_num);
502 int clean_io_failure(struct btrfs_fs_info *fs_info,
503 		     struct extent_io_tree *failure_tree,
504 		     struct extent_io_tree *io_tree, u64 start,
505 		     struct page *page, u64 ino, unsigned int pg_offset);
506 void end_extent_writepage(struct page *page, int err, u64 start, u64 end);
507 int repair_eb_io_failure(struct btrfs_fs_info *fs_info,
508 			 struct extent_buffer *eb, int mirror_num);
509 
510 /*
511  * When IO fails, either with EIO or csum verification fails, we
512  * try other mirrors that might have a good copy of the data.  This
513  * io_failure_record is used to record state as we go through all the
514  * mirrors.  If another mirror has good data, the page is set up to date
515  * and things continue.  If a good mirror can't be found, the original
516  * bio end_io callback is called to indicate things have failed.
517  */
518 struct io_failure_record {
519 	struct page *page;
520 	u64 start;
521 	u64 len;
522 	u64 logical;
523 	unsigned long bio_flags;
524 	int this_mirror;
525 	int failed_mirror;
526 	int in_validation;
527 };
528 
529 
530 void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start,
531 		u64 end);
532 int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
533 				struct io_failure_record **failrec_ret);
534 bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
535 			    struct io_failure_record *failrec, int fail_mirror);
536 struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
537 				    struct io_failure_record *failrec,
538 				    struct page *page, int pg_offset, int icsum,
539 				    bio_end_io_t *endio_func, void *data);
540 int free_io_failure(struct extent_io_tree *failure_tree,
541 		    struct extent_io_tree *io_tree,
542 		    struct io_failure_record *rec);
543 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
544 noinline u64 find_lock_delalloc_range(struct inode *inode,
545 				      struct extent_io_tree *tree,
546 				      struct page *locked_page, u64 *start,
547 				      u64 *end, u64 max_bytes);
548 #endif
549 struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
550 					       u64 start);
551 
552 #endif
553