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_DUMMY 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 static inline int le_test_bit(int nr, const u8 *addr) 83 { 84 return 1U & (addr[BIT_BYTE(nr)] >> (nr & (BITS_PER_BYTE-1))); 85 } 86 87 void le_bitmap_set(u8 *map, unsigned int start, int len); 88 void le_bitmap_clear(u8 *map, unsigned int start, int len); 89 90 struct extent_state; 91 struct btrfs_root; 92 struct btrfs_inode; 93 struct btrfs_io_bio; 94 struct io_failure_record; 95 96 typedef blk_status_t (extent_submit_bio_hook_t)(void *private_data, struct bio *bio, 97 int mirror_num, unsigned long bio_flags, 98 u64 bio_offset); 99 100 typedef blk_status_t (extent_submit_bio_start_t)(void *private_data, 101 struct bio *bio, u64 bio_offset); 102 103 typedef blk_status_t (extent_submit_bio_done_t)(void *private_data, 104 struct bio *bio, int mirror_num); 105 106 struct extent_io_ops { 107 /* 108 * The following callbacks must be allways defined, the function 109 * pointer will be called unconditionally. 110 */ 111 extent_submit_bio_hook_t *submit_bio_hook; 112 int (*readpage_end_io_hook)(struct btrfs_io_bio *io_bio, u64 phy_offset, 113 struct page *page, u64 start, u64 end, 114 int mirror); 115 int (*merge_bio_hook)(struct page *page, unsigned long offset, 116 size_t size, struct bio *bio, 117 unsigned long bio_flags); 118 int (*readpage_io_failed_hook)(struct page *page, int failed_mirror); 119 struct btrfs_fs_info *(*tree_fs_info)(void *private_data); 120 void (*set_range_writeback)(void *private_data, u64 start, u64 end); 121 122 /* 123 * Optional hooks, called if the pointer is not NULL 124 */ 125 int (*fill_delalloc)(void *private_data, struct page *locked_page, 126 u64 start, u64 end, int *page_started, 127 unsigned long *nr_written, 128 struct writeback_control *wbc); 129 130 int (*writepage_start_hook)(struct page *page, u64 start, u64 end); 131 void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end, 132 struct extent_state *state, int uptodate); 133 void (*set_bit_hook)(void *private_data, struct extent_state *state, 134 unsigned *bits); 135 void (*clear_bit_hook)(void *private_data, 136 struct extent_state *state, 137 unsigned *bits); 138 void (*merge_extent_hook)(void *private_data, 139 struct extent_state *new, 140 struct extent_state *other); 141 void (*split_extent_hook)(void *private_data, 142 struct extent_state *orig, u64 split); 143 void (*check_extent_io_range)(void *private_data, const char *caller, 144 u64 start, u64 end); 145 }; 146 147 struct extent_io_tree { 148 struct rb_root state; 149 void *private_data; 150 u64 dirty_bytes; 151 int track_uptodate; 152 spinlock_t lock; 153 const struct extent_io_ops *ops; 154 }; 155 156 struct extent_state { 157 u64 start; 158 u64 end; /* inclusive */ 159 struct rb_node rb_node; 160 161 /* ADD NEW ELEMENTS AFTER THIS */ 162 wait_queue_head_t wq; 163 refcount_t refs; 164 unsigned state; 165 166 struct io_failure_record *failrec; 167 168 #ifdef CONFIG_BTRFS_DEBUG 169 struct list_head leak_list; 170 #endif 171 }; 172 173 #define INLINE_EXTENT_BUFFER_PAGES 16 174 #define MAX_INLINE_EXTENT_BUFFER_SIZE (INLINE_EXTENT_BUFFER_PAGES * PAGE_SIZE) 175 struct extent_buffer { 176 u64 start; 177 unsigned long len; 178 unsigned long bflags; 179 struct btrfs_fs_info *fs_info; 180 spinlock_t refs_lock; 181 atomic_t refs; 182 atomic_t io_pages; 183 int read_mirror; 184 struct rcu_head rcu_head; 185 pid_t lock_owner; 186 187 /* count of read lock holders on the extent buffer */ 188 atomic_t write_locks; 189 atomic_t read_locks; 190 atomic_t blocking_writers; 191 atomic_t blocking_readers; 192 atomic_t spinning_readers; 193 atomic_t spinning_writers; 194 short lock_nested; 195 /* >= 0 if eb belongs to a log tree, -1 otherwise */ 196 short log_index; 197 198 /* protects write locks */ 199 rwlock_t lock; 200 201 /* readers use lock_wq while they wait for the write 202 * lock holders to unlock 203 */ 204 wait_queue_head_t write_lock_wq; 205 206 /* writers use read_lock_wq while they wait for readers 207 * to unlock 208 */ 209 wait_queue_head_t read_lock_wq; 210 struct page *pages[INLINE_EXTENT_BUFFER_PAGES]; 211 #ifdef CONFIG_BTRFS_DEBUG 212 struct list_head leak_list; 213 #endif 214 }; 215 216 /* 217 * Structure to record how many bytes and which ranges are set/cleared 218 */ 219 struct extent_changeset { 220 /* How many bytes are set/cleared in this operation */ 221 unsigned int bytes_changed; 222 223 /* Changed ranges */ 224 struct ulist range_changed; 225 }; 226 227 static inline void extent_changeset_init(struct extent_changeset *changeset) 228 { 229 changeset->bytes_changed = 0; 230 ulist_init(&changeset->range_changed); 231 } 232 233 static inline struct extent_changeset *extent_changeset_alloc(void) 234 { 235 struct extent_changeset *ret; 236 237 ret = kmalloc(sizeof(*ret), GFP_KERNEL); 238 if (!ret) 239 return NULL; 240 241 extent_changeset_init(ret); 242 return ret; 243 } 244 245 static inline void extent_changeset_release(struct extent_changeset *changeset) 246 { 247 if (!changeset) 248 return; 249 changeset->bytes_changed = 0; 250 ulist_release(&changeset->range_changed); 251 } 252 253 static inline void extent_changeset_free(struct extent_changeset *changeset) 254 { 255 if (!changeset) 256 return; 257 extent_changeset_release(changeset); 258 kfree(changeset); 259 } 260 261 static inline void extent_set_compress_type(unsigned long *bio_flags, 262 int compress_type) 263 { 264 *bio_flags |= compress_type << EXTENT_BIO_FLAG_SHIFT; 265 } 266 267 static inline int extent_compress_type(unsigned long bio_flags) 268 { 269 return bio_flags >> EXTENT_BIO_FLAG_SHIFT; 270 } 271 272 struct extent_map_tree; 273 274 typedef struct extent_map *(get_extent_t)(struct btrfs_inode *inode, 275 struct page *page, 276 size_t pg_offset, 277 u64 start, u64 len, 278 int create); 279 280 void extent_io_tree_init(struct extent_io_tree *tree, void *private_data); 281 int try_release_extent_mapping(struct extent_map_tree *map, 282 struct extent_io_tree *tree, struct page *page, 283 gfp_t mask); 284 int try_release_extent_buffer(struct page *page); 285 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, 286 struct extent_state **cached); 287 288 static inline int lock_extent(struct extent_io_tree *tree, u64 start, u64 end) 289 { 290 return lock_extent_bits(tree, start, end, NULL); 291 } 292 293 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end); 294 int extent_read_full_page(struct extent_io_tree *tree, struct page *page, 295 get_extent_t *get_extent, int mirror_num); 296 int __init extent_io_init(void); 297 void __cold extent_io_exit(void); 298 299 u64 count_range_bits(struct extent_io_tree *tree, 300 u64 *start, u64 search_end, 301 u64 max_bytes, unsigned bits, int contig); 302 303 void free_extent_state(struct extent_state *state); 304 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end, 305 unsigned bits, int filled, 306 struct extent_state *cached_state); 307 int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, 308 unsigned bits, struct extent_changeset *changeset); 309 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, 310 unsigned bits, int wake, int delete, 311 struct extent_state **cached); 312 int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, 313 unsigned bits, int wake, int delete, 314 struct extent_state **cached, gfp_t mask, 315 struct extent_changeset *changeset); 316 317 static inline int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end) 318 { 319 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL); 320 } 321 322 static inline int unlock_extent_cached(struct extent_io_tree *tree, u64 start, 323 u64 end, struct extent_state **cached) 324 { 325 return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached, 326 GFP_NOFS, NULL); 327 } 328 329 static inline int unlock_extent_cached_atomic(struct extent_io_tree *tree, 330 u64 start, u64 end, struct extent_state **cached) 331 { 332 return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached, 333 GFP_ATOMIC, NULL); 334 } 335 336 static inline int clear_extent_bits(struct extent_io_tree *tree, u64 start, 337 u64 end, unsigned bits) 338 { 339 int wake = 0; 340 341 if (bits & EXTENT_LOCKED) 342 wake = 1; 343 344 return clear_extent_bit(tree, start, end, bits, wake, 0, NULL); 345 } 346 347 int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, 348 unsigned bits, struct extent_changeset *changeset); 349 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, 350 unsigned bits, u64 *failed_start, 351 struct extent_state **cached_state, gfp_t mask); 352 353 static inline int set_extent_bits(struct extent_io_tree *tree, u64 start, 354 u64 end, unsigned bits) 355 { 356 return set_extent_bit(tree, start, end, bits, NULL, NULL, GFP_NOFS); 357 } 358 359 static inline int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, 360 u64 end, struct extent_state **cached_state) 361 { 362 return __clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, 363 cached_state, GFP_NOFS, NULL); 364 } 365 366 static inline int set_extent_dirty(struct extent_io_tree *tree, u64 start, 367 u64 end, gfp_t mask) 368 { 369 return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL, 370 NULL, mask); 371 } 372 373 static inline int clear_extent_dirty(struct extent_io_tree *tree, u64 start, 374 u64 end) 375 { 376 return clear_extent_bit(tree, start, end, 377 EXTENT_DIRTY | EXTENT_DELALLOC | 378 EXTENT_DO_ACCOUNTING, 0, 0, NULL); 379 } 380 381 int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, 382 unsigned bits, unsigned clear_bits, 383 struct extent_state **cached_state); 384 385 static inline int set_extent_delalloc(struct extent_io_tree *tree, u64 start, 386 u64 end, unsigned int extra_bits, 387 struct extent_state **cached_state) 388 { 389 return set_extent_bit(tree, start, end, 390 EXTENT_DELALLOC | EXTENT_UPTODATE | extra_bits, 391 NULL, cached_state, GFP_NOFS); 392 } 393 394 static inline int set_extent_defrag(struct extent_io_tree *tree, u64 start, 395 u64 end, struct extent_state **cached_state) 396 { 397 return set_extent_bit(tree, start, end, 398 EXTENT_DELALLOC | EXTENT_UPTODATE | EXTENT_DEFRAG, 399 NULL, cached_state, GFP_NOFS); 400 } 401 402 static inline int set_extent_new(struct extent_io_tree *tree, u64 start, 403 u64 end) 404 { 405 return set_extent_bit(tree, start, end, EXTENT_NEW, NULL, NULL, 406 GFP_NOFS); 407 } 408 409 static inline int set_extent_uptodate(struct extent_io_tree *tree, u64 start, 410 u64 end, struct extent_state **cached_state, gfp_t mask) 411 { 412 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL, 413 cached_state, mask); 414 } 415 416 int find_first_extent_bit(struct extent_io_tree *tree, u64 start, 417 u64 *start_ret, u64 *end_ret, unsigned bits, 418 struct extent_state **cached_state); 419 int extent_invalidatepage(struct extent_io_tree *tree, 420 struct page *page, unsigned long offset); 421 int extent_write_full_page(struct page *page, struct writeback_control *wbc); 422 int extent_write_locked_range(struct inode *inode, u64 start, u64 end, 423 int mode); 424 int extent_writepages(struct extent_io_tree *tree, 425 struct address_space *mapping, 426 struct writeback_control *wbc); 427 int btree_write_cache_pages(struct address_space *mapping, 428 struct writeback_control *wbc); 429 int extent_readpages(struct extent_io_tree *tree, 430 struct address_space *mapping, 431 struct list_head *pages, unsigned nr_pages); 432 int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 433 __u64 start, __u64 len); 434 void set_page_extent_mapped(struct page *page); 435 436 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info, 437 u64 start); 438 struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info, 439 u64 start, unsigned long len); 440 struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info, 441 u64 start); 442 struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src); 443 struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info, 444 u64 start); 445 void free_extent_buffer(struct extent_buffer *eb); 446 void free_extent_buffer_stale(struct extent_buffer *eb); 447 #define WAIT_NONE 0 448 #define WAIT_COMPLETE 1 449 #define WAIT_PAGE_LOCK 2 450 int read_extent_buffer_pages(struct extent_io_tree *tree, 451 struct extent_buffer *eb, int wait, 452 int mirror_num); 453 void wait_on_extent_buffer_writeback(struct extent_buffer *eb); 454 455 static inline unsigned long num_extent_pages(u64 start, u64 len) 456 { 457 return ((start + len + PAGE_SIZE - 1) >> PAGE_SHIFT) - 458 (start >> PAGE_SHIFT); 459 } 460 461 static inline void extent_buffer_get(struct extent_buffer *eb) 462 { 463 atomic_inc(&eb->refs); 464 } 465 466 static inline int extent_buffer_uptodate(struct extent_buffer *eb) 467 { 468 return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags); 469 } 470 471 int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv, 472 unsigned long start, unsigned long len); 473 void read_extent_buffer(const struct extent_buffer *eb, void *dst, 474 unsigned long start, 475 unsigned long len); 476 int read_extent_buffer_to_user(const struct extent_buffer *eb, 477 void __user *dst, unsigned long start, 478 unsigned long len); 479 void write_extent_buffer_fsid(struct extent_buffer *eb, const void *src); 480 void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb, 481 const void *src); 482 void write_extent_buffer(struct extent_buffer *eb, const void *src, 483 unsigned long start, unsigned long len); 484 void copy_extent_buffer_full(struct extent_buffer *dst, 485 struct extent_buffer *src); 486 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src, 487 unsigned long dst_offset, unsigned long src_offset, 488 unsigned long len); 489 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset, 490 unsigned long src_offset, unsigned long len); 491 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset, 492 unsigned long src_offset, unsigned long len); 493 void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start, 494 unsigned long len); 495 int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start, 496 unsigned long pos); 497 void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start, 498 unsigned long pos, unsigned long len); 499 void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start, 500 unsigned long pos, unsigned long len); 501 void clear_extent_buffer_dirty(struct extent_buffer *eb); 502 int set_extent_buffer_dirty(struct extent_buffer *eb); 503 void set_extent_buffer_uptodate(struct extent_buffer *eb); 504 void clear_extent_buffer_uptodate(struct extent_buffer *eb); 505 int extent_buffer_under_io(struct extent_buffer *eb); 506 int map_private_extent_buffer(const struct extent_buffer *eb, 507 unsigned long offset, unsigned long min_len, 508 char **map, unsigned long *map_start, 509 unsigned long *map_len); 510 void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end); 511 void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end); 512 void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end, 513 u64 delalloc_end, struct page *locked_page, 514 unsigned bits_to_clear, 515 unsigned long page_ops); 516 struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_byte); 517 struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs); 518 struct bio *btrfs_bio_clone(struct bio *bio); 519 struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size); 520 521 struct btrfs_fs_info; 522 struct btrfs_inode; 523 524 int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start, 525 u64 length, u64 logical, struct page *page, 526 unsigned int pg_offset, int mirror_num); 527 int clean_io_failure(struct btrfs_fs_info *fs_info, 528 struct extent_io_tree *failure_tree, 529 struct extent_io_tree *io_tree, u64 start, 530 struct page *page, u64 ino, unsigned int pg_offset); 531 void end_extent_writepage(struct page *page, int err, u64 start, u64 end); 532 int repair_eb_io_failure(struct btrfs_fs_info *fs_info, 533 struct extent_buffer *eb, int mirror_num); 534 535 /* 536 * When IO fails, either with EIO or csum verification fails, we 537 * try other mirrors that might have a good copy of the data. This 538 * io_failure_record is used to record state as we go through all the 539 * mirrors. If another mirror has good data, the page is set up to date 540 * and things continue. If a good mirror can't be found, the original 541 * bio end_io callback is called to indicate things have failed. 542 */ 543 struct io_failure_record { 544 struct page *page; 545 u64 start; 546 u64 len; 547 u64 logical; 548 unsigned long bio_flags; 549 int this_mirror; 550 int failed_mirror; 551 int in_validation; 552 }; 553 554 555 void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, 556 u64 end); 557 int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end, 558 struct io_failure_record **failrec_ret); 559 bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages, 560 struct io_failure_record *failrec, int fail_mirror); 561 struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio, 562 struct io_failure_record *failrec, 563 struct page *page, int pg_offset, int icsum, 564 bio_end_io_t *endio_func, void *data); 565 int free_io_failure(struct extent_io_tree *failure_tree, 566 struct extent_io_tree *io_tree, 567 struct io_failure_record *rec); 568 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS 569 noinline u64 find_lock_delalloc_range(struct inode *inode, 570 struct extent_io_tree *tree, 571 struct page *locked_page, u64 *start, 572 u64 *end, u64 max_bytes); 573 #endif 574 struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info, 575 u64 start); 576 577 #endif 578