xref: /openbmc/linux/fs/btrfs/extent_io.h (revision 0c874100)
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 (*fill_delalloc)(void *private_data, struct page *locked_page,
110 			     u64 start, u64 end, int *page_started,
111 			     unsigned long *nr_written,
112 			     struct writeback_control *wbc);
113 
114 	int (*writepage_start_hook)(struct page *page, u64 start, u64 end);
115 	void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end,
116 				      struct extent_state *state, int uptodate);
117 	void (*set_bit_hook)(void *private_data, struct extent_state *state,
118 			     unsigned *bits);
119 	void (*clear_bit_hook)(void *private_data,
120 			struct extent_state *state,
121 			unsigned *bits);
122 	void (*merge_extent_hook)(void *private_data,
123 				  struct extent_state *new,
124 				  struct extent_state *other);
125 	void (*split_extent_hook)(void *private_data,
126 				  struct extent_state *orig, u64 split);
127 	void (*check_extent_io_range)(void *private_data, const char *caller,
128 				      u64 start, u64 end);
129 };
130 
131 struct extent_io_tree {
132 	struct rb_root state;
133 	void *private_data;
134 	u64 dirty_bytes;
135 	int track_uptodate;
136 	spinlock_t lock;
137 	const struct extent_io_ops *ops;
138 };
139 
140 struct extent_state {
141 	u64 start;
142 	u64 end; /* inclusive */
143 	struct rb_node rb_node;
144 
145 	/* ADD NEW ELEMENTS AFTER THIS */
146 	wait_queue_head_t wq;
147 	refcount_t refs;
148 	unsigned state;
149 
150 	struct io_failure_record *failrec;
151 
152 #ifdef CONFIG_BTRFS_DEBUG
153 	struct list_head leak_list;
154 #endif
155 };
156 
157 #define INLINE_EXTENT_BUFFER_PAGES 16
158 #define MAX_INLINE_EXTENT_BUFFER_SIZE (INLINE_EXTENT_BUFFER_PAGES * PAGE_SIZE)
159 struct extent_buffer {
160 	u64 start;
161 	unsigned long len;
162 	unsigned long bflags;
163 	struct btrfs_fs_info *fs_info;
164 	spinlock_t refs_lock;
165 	atomic_t refs;
166 	atomic_t io_pages;
167 	int read_mirror;
168 	struct rcu_head rcu_head;
169 	pid_t lock_owner;
170 
171 	/* count of read lock holders on the extent buffer */
172 	atomic_t write_locks;
173 	atomic_t read_locks;
174 	atomic_t blocking_writers;
175 	atomic_t blocking_readers;
176 	atomic_t spinning_readers;
177 	atomic_t spinning_writers;
178 	short lock_nested;
179 	/* >= 0 if eb belongs to a log tree, -1 otherwise */
180 	short log_index;
181 
182 	/* protects write locks */
183 	rwlock_t lock;
184 
185 	/* readers use lock_wq while they wait for the write
186 	 * lock holders to unlock
187 	 */
188 	wait_queue_head_t write_lock_wq;
189 
190 	/* writers use read_lock_wq while they wait for readers
191 	 * to unlock
192 	 */
193 	wait_queue_head_t read_lock_wq;
194 	struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
195 #ifdef CONFIG_BTRFS_DEBUG
196 	struct list_head leak_list;
197 #endif
198 };
199 
200 /*
201  * Structure to record how many bytes and which ranges are set/cleared
202  */
203 struct extent_changeset {
204 	/* How many bytes are set/cleared in this operation */
205 	unsigned int bytes_changed;
206 
207 	/* Changed ranges */
208 	struct ulist range_changed;
209 };
210 
211 static inline void extent_changeset_init(struct extent_changeset *changeset)
212 {
213 	changeset->bytes_changed = 0;
214 	ulist_init(&changeset->range_changed);
215 }
216 
217 static inline struct extent_changeset *extent_changeset_alloc(void)
218 {
219 	struct extent_changeset *ret;
220 
221 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
222 	if (!ret)
223 		return NULL;
224 
225 	extent_changeset_init(ret);
226 	return ret;
227 }
228 
229 static inline void extent_changeset_release(struct extent_changeset *changeset)
230 {
231 	if (!changeset)
232 		return;
233 	changeset->bytes_changed = 0;
234 	ulist_release(&changeset->range_changed);
235 }
236 
237 static inline void extent_changeset_free(struct extent_changeset *changeset)
238 {
239 	if (!changeset)
240 		return;
241 	extent_changeset_release(changeset);
242 	kfree(changeset);
243 }
244 
245 static inline void extent_set_compress_type(unsigned long *bio_flags,
246 					    int compress_type)
247 {
248 	*bio_flags |= compress_type << EXTENT_BIO_FLAG_SHIFT;
249 }
250 
251 static inline int extent_compress_type(unsigned long bio_flags)
252 {
253 	return bio_flags >> EXTENT_BIO_FLAG_SHIFT;
254 }
255 
256 struct extent_map_tree;
257 
258 typedef struct extent_map *(get_extent_t)(struct btrfs_inode *inode,
259 					  struct page *page,
260 					  size_t pg_offset,
261 					  u64 start, u64 len,
262 					  int create);
263 
264 void extent_io_tree_init(struct extent_io_tree *tree, void *private_data);
265 int try_release_extent_mapping(struct page *page, gfp_t mask);
266 int try_release_extent_buffer(struct page *page);
267 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
268 		     struct extent_state **cached);
269 
270 static inline int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
271 {
272 	return lock_extent_bits(tree, start, end, NULL);
273 }
274 
275 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end);
276 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
277 			  get_extent_t *get_extent, int mirror_num);
278 int __init extent_io_init(void);
279 void __cold extent_io_exit(void);
280 
281 u64 count_range_bits(struct extent_io_tree *tree,
282 		     u64 *start, u64 search_end,
283 		     u64 max_bytes, unsigned bits, int contig);
284 
285 void free_extent_state(struct extent_state *state);
286 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
287 		   unsigned bits, int filled,
288 		   struct extent_state *cached_state);
289 int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
290 		unsigned bits, struct extent_changeset *changeset);
291 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
292 		     unsigned bits, int wake, int delete,
293 		     struct extent_state **cached);
294 int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
295 		     unsigned bits, int wake, int delete,
296 		     struct extent_state **cached, gfp_t mask,
297 		     struct extent_changeset *changeset);
298 
299 static inline int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
300 {
301 	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL);
302 }
303 
304 static inline int unlock_extent_cached(struct extent_io_tree *tree, u64 start,
305 		u64 end, struct extent_state **cached)
306 {
307 	return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
308 				GFP_NOFS, NULL);
309 }
310 
311 static inline int unlock_extent_cached_atomic(struct extent_io_tree *tree,
312 		u64 start, u64 end, struct extent_state **cached)
313 {
314 	return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
315 				GFP_ATOMIC, NULL);
316 }
317 
318 static inline int clear_extent_bits(struct extent_io_tree *tree, u64 start,
319 		u64 end, unsigned bits)
320 {
321 	int wake = 0;
322 
323 	if (bits & EXTENT_LOCKED)
324 		wake = 1;
325 
326 	return clear_extent_bit(tree, start, end, bits, wake, 0, NULL);
327 }
328 
329 int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
330 			   unsigned bits, struct extent_changeset *changeset);
331 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
332 		   unsigned bits, u64 *failed_start,
333 		   struct extent_state **cached_state, gfp_t mask);
334 
335 static inline int set_extent_bits(struct extent_io_tree *tree, u64 start,
336 		u64 end, unsigned bits)
337 {
338 	return set_extent_bit(tree, start, end, bits, NULL, NULL, GFP_NOFS);
339 }
340 
341 static inline int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
342 		u64 end, struct extent_state **cached_state)
343 {
344 	return __clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
345 				cached_state, GFP_NOFS, NULL);
346 }
347 
348 static inline int set_extent_dirty(struct extent_io_tree *tree, u64 start,
349 		u64 end, gfp_t mask)
350 {
351 	return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
352 			      NULL, mask);
353 }
354 
355 static inline int clear_extent_dirty(struct extent_io_tree *tree, u64 start,
356 		u64 end)
357 {
358 	return clear_extent_bit(tree, start, end,
359 				EXTENT_DIRTY | EXTENT_DELALLOC |
360 				EXTENT_DO_ACCOUNTING, 0, 0, NULL);
361 }
362 
363 int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
364 		       unsigned bits, unsigned clear_bits,
365 		       struct extent_state **cached_state);
366 
367 static inline int set_extent_delalloc(struct extent_io_tree *tree, u64 start,
368 				      u64 end, unsigned int extra_bits,
369 				      struct extent_state **cached_state)
370 {
371 	return set_extent_bit(tree, start, end,
372 			      EXTENT_DELALLOC | EXTENT_UPTODATE | extra_bits,
373 			      NULL, cached_state, GFP_NOFS);
374 }
375 
376 static inline int set_extent_defrag(struct extent_io_tree *tree, u64 start,
377 		u64 end, struct extent_state **cached_state)
378 {
379 	return set_extent_bit(tree, start, end,
380 			      EXTENT_DELALLOC | EXTENT_UPTODATE | EXTENT_DEFRAG,
381 			      NULL, cached_state, GFP_NOFS);
382 }
383 
384 static inline int set_extent_new(struct extent_io_tree *tree, u64 start,
385 		u64 end)
386 {
387 	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL, NULL,
388 			GFP_NOFS);
389 }
390 
391 static inline int set_extent_uptodate(struct extent_io_tree *tree, u64 start,
392 		u64 end, struct extent_state **cached_state, gfp_t mask)
393 {
394 	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL,
395 			      cached_state, mask);
396 }
397 
398 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
399 			  u64 *start_ret, u64 *end_ret, unsigned bits,
400 			  struct extent_state **cached_state);
401 int extent_invalidatepage(struct extent_io_tree *tree,
402 			  struct page *page, unsigned long offset);
403 int extent_write_full_page(struct page *page, struct writeback_control *wbc);
404 int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
405 			      int mode);
406 int extent_writepages(struct address_space *mapping,
407 		      struct writeback_control *wbc);
408 int btree_write_cache_pages(struct address_space *mapping,
409 			    struct writeback_control *wbc);
410 int extent_readpages(struct address_space *mapping, struct list_head *pages,
411 		     unsigned nr_pages);
412 int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
413 		__u64 start, __u64 len);
414 void set_page_extent_mapped(struct page *page);
415 
416 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
417 					  u64 start);
418 struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
419 						  u64 start, unsigned long len);
420 struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
421 						u64 start);
422 struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src);
423 struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
424 					 u64 start);
425 void free_extent_buffer(struct extent_buffer *eb);
426 void free_extent_buffer_stale(struct extent_buffer *eb);
427 #define WAIT_NONE	0
428 #define WAIT_COMPLETE	1
429 #define WAIT_PAGE_LOCK	2
430 int read_extent_buffer_pages(struct extent_io_tree *tree,
431 			     struct extent_buffer *eb, int wait,
432 			     int mirror_num);
433 void wait_on_extent_buffer_writeback(struct extent_buffer *eb);
434 
435 static inline int num_extent_pages(const struct extent_buffer *eb)
436 {
437 	return (round_up(eb->start + eb->len, PAGE_SIZE) >> PAGE_SHIFT) -
438 	       (eb->start >> PAGE_SHIFT);
439 }
440 
441 static inline void extent_buffer_get(struct extent_buffer *eb)
442 {
443 	atomic_inc(&eb->refs);
444 }
445 
446 static inline int extent_buffer_uptodate(struct extent_buffer *eb)
447 {
448 	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
449 }
450 
451 int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
452 			 unsigned long start, unsigned long len);
453 void read_extent_buffer(const struct extent_buffer *eb, void *dst,
454 			unsigned long start,
455 			unsigned long len);
456 int read_extent_buffer_to_user(const struct extent_buffer *eb,
457 			       void __user *dst, unsigned long start,
458 			       unsigned long len);
459 void write_extent_buffer_fsid(struct extent_buffer *eb, const void *src);
460 void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
461 		const void *src);
462 void write_extent_buffer(struct extent_buffer *eb, const void *src,
463 			 unsigned long start, unsigned long len);
464 void copy_extent_buffer_full(struct extent_buffer *dst,
465 			     struct extent_buffer *src);
466 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
467 			unsigned long dst_offset, unsigned long src_offset,
468 			unsigned long len);
469 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
470 			   unsigned long src_offset, unsigned long len);
471 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
472 			   unsigned long src_offset, unsigned long len);
473 void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
474 			   unsigned long len);
475 int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
476 			   unsigned long pos);
477 void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
478 			      unsigned long pos, unsigned long len);
479 void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
480 				unsigned long pos, unsigned long len);
481 void clear_extent_buffer_dirty(struct extent_buffer *eb);
482 bool set_extent_buffer_dirty(struct extent_buffer *eb);
483 void set_extent_buffer_uptodate(struct extent_buffer *eb);
484 void clear_extent_buffer_uptodate(struct extent_buffer *eb);
485 int extent_buffer_under_io(struct extent_buffer *eb);
486 int map_private_extent_buffer(const struct extent_buffer *eb,
487 			      unsigned long offset, unsigned long min_len,
488 			      char **map, unsigned long *map_start,
489 			      unsigned long *map_len);
490 void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end);
491 void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end);
492 void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
493 				 u64 delalloc_end, struct page *locked_page,
494 				 unsigned bits_to_clear,
495 				 unsigned long page_ops);
496 struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_byte);
497 struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs);
498 struct bio *btrfs_bio_clone(struct bio *bio);
499 struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size);
500 
501 struct btrfs_fs_info;
502 struct btrfs_inode;
503 
504 int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
505 		      u64 length, u64 logical, struct page *page,
506 		      unsigned int pg_offset, int mirror_num);
507 int clean_io_failure(struct btrfs_fs_info *fs_info,
508 		     struct extent_io_tree *failure_tree,
509 		     struct extent_io_tree *io_tree, u64 start,
510 		     struct page *page, u64 ino, unsigned int pg_offset);
511 void end_extent_writepage(struct page *page, int err, u64 start, u64 end);
512 int repair_eb_io_failure(struct btrfs_fs_info *fs_info,
513 			 struct extent_buffer *eb, int mirror_num);
514 
515 /*
516  * When IO fails, either with EIO or csum verification fails, we
517  * try other mirrors that might have a good copy of the data.  This
518  * io_failure_record is used to record state as we go through all the
519  * mirrors.  If another mirror has good data, the page is set up to date
520  * and things continue.  If a good mirror can't be found, the original
521  * bio end_io callback is called to indicate things have failed.
522  */
523 struct io_failure_record {
524 	struct page *page;
525 	u64 start;
526 	u64 len;
527 	u64 logical;
528 	unsigned long bio_flags;
529 	int this_mirror;
530 	int failed_mirror;
531 	int in_validation;
532 };
533 
534 
535 void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start,
536 		u64 end);
537 int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
538 				struct io_failure_record **failrec_ret);
539 bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
540 			    struct io_failure_record *failrec, int fail_mirror);
541 struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
542 				    struct io_failure_record *failrec,
543 				    struct page *page, int pg_offset, int icsum,
544 				    bio_end_io_t *endio_func, void *data);
545 int free_io_failure(struct extent_io_tree *failure_tree,
546 		    struct extent_io_tree *io_tree,
547 		    struct io_failure_record *rec);
548 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
549 u64 btrfs_find_lock_delalloc_range(struct inode *inode,
550 				      struct extent_io_tree *tree,
551 				      struct page *locked_page, u64 *start,
552 				      u64 *end, u64 max_bytes);
553 #endif
554 struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
555 					       u64 start);
556 
557 #endif
558