Commit | Line | Data |
---|---|---|
b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | /* |
3 | * include/linux/buffer_head.h | |
4 | * | |
5 | * Everything to do with buffer_heads. | |
6 | */ | |
7 | ||
8 | #ifndef _LINUX_BUFFER_HEAD_H | |
9 | #define _LINUX_BUFFER_HEAD_H | |
10 | ||
11 | #include <linux/types.h> | |
12 | #include <linux/fs.h> | |
13 | #include <linux/linkage.h> | |
14 | #include <linux/pagemap.h> | |
15 | #include <linux/wait.h> | |
60063497 | 16 | #include <linux/atomic.h> |
1da177e4 | 17 | |
9361401e DH |
18 | #ifdef CONFIG_BLOCK |
19 | ||
1da177e4 LT |
20 | enum bh_state_bits { |
21 | BH_Uptodate, /* Contains valid data */ | |
22 | BH_Dirty, /* Is dirty */ | |
23 | BH_Lock, /* Is locked */ | |
24 | BH_Req, /* Has been submitted for I/O */ | |
25 | ||
26 | BH_Mapped, /* Has a disk mapping */ | |
27 | BH_New, /* Disk mapping was newly created by get_block */ | |
28 | BH_Async_Read, /* Is under end_buffer_async_read I/O */ | |
29 | BH_Async_Write, /* Is under end_buffer_async_write I/O */ | |
30 | BH_Delay, /* Buffer is not yet allocated on disk */ | |
31 | BH_Boundary, /* Block is followed by a discontiguity */ | |
32 | BH_Write_EIO, /* I/O error on write */ | |
33a266dd | 33 | BH_Unwritten, /* Buffer is allocated on disk but not written */ |
08bafc03 | 34 | BH_Quiet, /* Buffer Error Prinks to be quiet */ |
877f962c TT |
35 | BH_Meta, /* Buffer contains metadata */ |
36 | BH_Prio, /* Buffer should be submitted with REQ_PRIO */ | |
7b7a8665 | 37 | BH_Defer_Completion, /* Defer AIO completion to workqueue */ |
1da177e4 LT |
38 | |
39 | BH_PrivateStart,/* not a state bit, but the first bit available | |
40 | * for private allocation by other entities | |
41 | */ | |
42 | }; | |
43 | ||
09cbfeaf | 44 | #define MAX_BUF_PER_PAGE (PAGE_SIZE / 512) |
1da177e4 LT |
45 | |
46 | struct page; | |
47 | struct buffer_head; | |
48 | struct address_space; | |
49 | typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate); | |
50 | ||
51 | /* | |
205f87f6 BP |
52 | * Historically, a buffer_head was used to map a single block |
53 | * within a page, and of course as the unit of I/O through the | |
54 | * filesystem and block layers. Nowadays the basic I/O unit | |
55 | * is the bio, and buffer_heads are used for extracting block | |
56 | * mappings (via a get_block_t call), for tracking state within | |
57 | * a page (via a page_mapping) and for wrapping bio submission | |
58 | * for backward compatibility reasons (e.g. submit_bh). | |
1da177e4 LT |
59 | */ |
60 | struct buffer_head { | |
1da177e4 LT |
61 | unsigned long b_state; /* buffer state bitmap (see above) */ |
62 | struct buffer_head *b_this_page;/* circular list of page's buffers */ | |
63 | struct page *b_page; /* the page this bh is mapped to */ | |
1da177e4 | 64 | |
205f87f6 BP |
65 | sector_t b_blocknr; /* start block number */ |
66 | size_t b_size; /* size of mapping */ | |
67 | char *b_data; /* pointer to data within the page */ | |
1da177e4 LT |
68 | |
69 | struct block_device *b_bdev; | |
70 | bh_end_io_t *b_end_io; /* I/O completion */ | |
71 | void *b_private; /* reserved for b_end_io */ | |
72 | struct list_head b_assoc_buffers; /* associated with another mapping */ | |
58ff407b JK |
73 | struct address_space *b_assoc_map; /* mapping this buffer is |
74 | associated with */ | |
205f87f6 | 75 | atomic_t b_count; /* users using this buffer_head */ |
f1e67e35 TG |
76 | spinlock_t b_uptodate_lock; /* Used by the first bh in a page, to |
77 | * serialise IO completion of other | |
78 | * buffers in the page */ | |
1da177e4 LT |
79 | }; |
80 | ||
81 | /* | |
82 | * macro tricks to expand the set_buffer_foo(), clear_buffer_foo() | |
83 | * and buffer_foo() functions. | |
60f91826 KW |
84 | * To avoid reset buffer flags that are already set, because that causes |
85 | * a costly cache line transition, check the flag first. | |
1da177e4 LT |
86 | */ |
87 | #define BUFFER_FNS(bit, name) \ | |
ee91ef61 | 88 | static __always_inline void set_buffer_##name(struct buffer_head *bh) \ |
1da177e4 | 89 | { \ |
60f91826 KW |
90 | if (!test_bit(BH_##bit, &(bh)->b_state)) \ |
91 | set_bit(BH_##bit, &(bh)->b_state); \ | |
1da177e4 | 92 | } \ |
ee91ef61 | 93 | static __always_inline void clear_buffer_##name(struct buffer_head *bh) \ |
1da177e4 LT |
94 | { \ |
95 | clear_bit(BH_##bit, &(bh)->b_state); \ | |
96 | } \ | |
ee91ef61 | 97 | static __always_inline int buffer_##name(const struct buffer_head *bh) \ |
1da177e4 LT |
98 | { \ |
99 | return test_bit(BH_##bit, &(bh)->b_state); \ | |
100 | } | |
101 | ||
102 | /* | |
103 | * test_set_buffer_foo() and test_clear_buffer_foo() | |
104 | */ | |
105 | #define TAS_BUFFER_FNS(bit, name) \ | |
ee91ef61 | 106 | static __always_inline int test_set_buffer_##name(struct buffer_head *bh) \ |
1da177e4 LT |
107 | { \ |
108 | return test_and_set_bit(BH_##bit, &(bh)->b_state); \ | |
109 | } \ | |
ee91ef61 | 110 | static __always_inline int test_clear_buffer_##name(struct buffer_head *bh) \ |
1da177e4 LT |
111 | { \ |
112 | return test_and_clear_bit(BH_##bit, &(bh)->b_state); \ | |
113 | } \ | |
114 | ||
115 | /* | |
116 | * Emit the buffer bitops functions. Note that there are also functions | |
117 | * of the form "mark_buffer_foo()". These are higher-level functions which | |
118 | * do something in addition to setting a b_state bit. | |
119 | */ | |
120 | BUFFER_FNS(Uptodate, uptodate) | |
121 | BUFFER_FNS(Dirty, dirty) | |
122 | TAS_BUFFER_FNS(Dirty, dirty) | |
123 | BUFFER_FNS(Lock, locked) | |
1da177e4 LT |
124 | BUFFER_FNS(Req, req) |
125 | TAS_BUFFER_FNS(Req, req) | |
126 | BUFFER_FNS(Mapped, mapped) | |
127 | BUFFER_FNS(New, new) | |
128 | BUFFER_FNS(Async_Read, async_read) | |
129 | BUFFER_FNS(Async_Write, async_write) | |
130 | BUFFER_FNS(Delay, delay) | |
131 | BUFFER_FNS(Boundary, boundary) | |
132 | BUFFER_FNS(Write_EIO, write_io_error) | |
33a266dd | 133 | BUFFER_FNS(Unwritten, unwritten) |
877f962c TT |
134 | BUFFER_FNS(Meta, meta) |
135 | BUFFER_FNS(Prio, prio) | |
7b7a8665 | 136 | BUFFER_FNS(Defer_Completion, defer_completion) |
1da177e4 LT |
137 | |
138 | #define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK) | |
1da177e4 LT |
139 | |
140 | /* If we *know* page->private refers to buffer_heads */ | |
141 | #define page_buffers(page) \ | |
142 | ({ \ | |
4c21e2f2 HD |
143 | BUG_ON(!PagePrivate(page)); \ |
144 | ((struct buffer_head *)page_private(page)); \ | |
1da177e4 LT |
145 | }) |
146 | #define page_has_buffers(page) PagePrivate(page) | |
cd1067be | 147 | #define folio_buffers(folio) folio_get_private(folio) |
1da177e4 | 148 | |
520f301c | 149 | void buffer_check_dirty_writeback(struct folio *folio, |
b4597226 MG |
150 | bool *dirty, bool *writeback); |
151 | ||
1da177e4 LT |
152 | /* |
153 | * Declarations | |
154 | */ | |
155 | ||
b3c97528 | 156 | void mark_buffer_dirty(struct buffer_head *bh); |
87354e5d | 157 | void mark_buffer_write_io_error(struct buffer_head *bh); |
f0059afd | 158 | void touch_buffer(struct buffer_head *bh); |
1da177e4 LT |
159 | void set_bh_page(struct buffer_head *bh, |
160 | struct page *page, unsigned long offset); | |
68189fef | 161 | bool try_to_free_buffers(struct folio *); |
1da177e4 | 162 | struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, |
640ab98f | 163 | bool retry); |
1da177e4 LT |
164 | void create_empty_buffers(struct page *, unsigned long, |
165 | unsigned long b_state); | |
166 | void end_buffer_read_sync(struct buffer_head *bh, int uptodate); | |
167 | void end_buffer_write_sync(struct buffer_head *bh, int uptodate); | |
35c80d5f | 168 | void end_buffer_async_write(struct buffer_head *bh, int uptodate); |
1da177e4 LT |
169 | |
170 | /* Things to do with buffers at mapping->private_list */ | |
171 | void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode); | |
172 | int inode_has_buffers(struct inode *); | |
173 | void invalidate_inode_buffers(struct inode *); | |
174 | int remove_inode_buffers(struct inode *inode); | |
175 | int sync_mapping_buffers(struct address_space *mapping); | |
29f3ad7d JK |
176 | void clean_bdev_aliases(struct block_device *bdev, sector_t block, |
177 | sector_t len); | |
e64855c6 JK |
178 | static inline void clean_bdev_bh_alias(struct buffer_head *bh) |
179 | { | |
180 | clean_bdev_aliases(bh->b_bdev, bh->b_blocknr, 1); | |
181 | } | |
1da177e4 LT |
182 | |
183 | void mark_buffer_async_write(struct buffer_head *bh); | |
1da177e4 LT |
184 | void __wait_on_buffer(struct buffer_head *); |
185 | wait_queue_head_t *bh_waitq_head(struct buffer_head *bh); | |
3991d3bd TK |
186 | struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block, |
187 | unsigned size); | |
3b5e6454 GK |
188 | struct buffer_head *__getblk_gfp(struct block_device *bdev, sector_t block, |
189 | unsigned size, gfp_t gfp); | |
1da177e4 LT |
190 | void __brelse(struct buffer_head *); |
191 | void __bforget(struct buffer_head *); | |
3991d3bd | 192 | void __breadahead(struct block_device *, sector_t block, unsigned int size); |
d87f6392 RG |
193 | void __breadahead_gfp(struct block_device *, sector_t block, unsigned int size, |
194 | gfp_t gfp); | |
3b5e6454 GK |
195 | struct buffer_head *__bread_gfp(struct block_device *, |
196 | sector_t block, unsigned size, gfp_t gfp); | |
f9a14399 | 197 | void invalidate_bh_lrus(void); |
243418e3 | 198 | void invalidate_bh_lrus_cpu(void); |
8cc621d2 | 199 | bool has_bh_in_lru(int cpu, void *dummy); |
dd0fc66f | 200 | struct buffer_head *alloc_buffer_head(gfp_t gfp_flags); |
1da177e4 | 201 | void free_buffer_head(struct buffer_head * bh); |
b3c97528 HH |
202 | void unlock_buffer(struct buffer_head *bh); |
203 | void __lock_buffer(struct buffer_head *bh); | |
dfec8a14 | 204 | void ll_rw_block(int, int, int, struct buffer_head * bh[]); |
1da177e4 | 205 | int sync_dirty_buffer(struct buffer_head *bh); |
2a222ca9 MC |
206 | int __sync_dirty_buffer(struct buffer_head *bh, int op_flags); |
207 | void write_dirty_buffer(struct buffer_head *bh, int op_flags); | |
2a222ca9 | 208 | int submit_bh(int, int, struct buffer_head *); |
1da177e4 LT |
209 | void write_boundary_block(struct block_device *bdev, |
210 | sector_t bblock, unsigned blocksize); | |
389d1b08 AK |
211 | int bh_uptodate_or_lock(struct buffer_head *bh); |
212 | int bh_submit_read(struct buffer_head *bh); | |
1da177e4 LT |
213 | |
214 | extern int buffer_heads_over_limit; | |
215 | ||
216 | /* | |
217 | * Generic address_space_operations implementations for buffer_head-backed | |
218 | * address_spaces. | |
219 | */ | |
7ba13abb | 220 | void block_invalidate_folio(struct folio *folio, size_t offset, size_t length); |
1da177e4 LT |
221 | int block_write_full_page(struct page *page, get_block_t *get_block, |
222 | struct writeback_control *wbc); | |
b4bba389 BM |
223 | int __block_write_full_page(struct inode *inode, struct page *page, |
224 | get_block_t *get_block, struct writeback_control *wbc, | |
225 | bh_end_io_t *handler); | |
2c69e205 | 226 | int block_read_full_folio(struct folio *, get_block_t *); |
2e7e80f7 | 227 | bool block_is_partially_uptodate(struct folio *, size_t from, size_t count); |
155130a4 | 228 | int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, |
b3992d1e | 229 | struct page **pagep, get_block_t *get_block); |
6e1db88d CH |
230 | int __block_write_begin(struct page *page, loff_t pos, unsigned len, |
231 | get_block_t *get_block); | |
afddba49 NP |
232 | int block_write_end(struct file *, struct address_space *, |
233 | loff_t, unsigned, unsigned, | |
234 | struct page *, void *); | |
235 | int generic_write_end(struct file *, struct address_space *, | |
236 | loff_t, unsigned, unsigned, | |
237 | struct page *, void *); | |
238 | void page_zero_new_buffers(struct page *page, unsigned from, unsigned to); | |
f892760a | 239 | void clean_page_buffers(struct page *page); |
89e10787 | 240 | int cont_write_begin(struct file *, struct address_space *, loff_t, |
be3bbbc5 | 241 | unsigned, struct page **, void **, |
89e10787 | 242 | get_block_t *, loff_t *); |
05eb0b51 | 243 | int generic_cont_expand_simple(struct inode *inode, loff_t size); |
1da177e4 | 244 | int block_commit_write(struct page *page, unsigned from, unsigned to); |
c2ec175c | 245 | int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, |
54171690 | 246 | get_block_t get_block); |
24da4fab | 247 | /* Convert errno to return value from ->page_mkwrite() call */ |
401b25aa | 248 | static inline vm_fault_t block_page_mkwrite_return(int err) |
24da4fab JK |
249 | { |
250 | if (err == 0) | |
251 | return VM_FAULT_LOCKED; | |
0911d004 | 252 | if (err == -EFAULT || err == -EAGAIN) |
24da4fab JK |
253 | return VM_FAULT_NOPAGE; |
254 | if (err == -ENOMEM) | |
255 | return VM_FAULT_OOM; | |
256 | /* -ENOSPC, -EDQUOT, -EIO ... */ | |
257 | return VM_FAULT_SIGBUS; | |
258 | } | |
1da177e4 | 259 | sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); |
1da177e4 | 260 | int block_truncate_page(struct address_space *, loff_t, get_block_t *); |
8371f30c | 261 | int nobh_write_begin(struct address_space *, loff_t, unsigned len, |
03158cd7 NP |
262 | struct page **, void **, get_block_t*); |
263 | int nobh_write_end(struct file *, struct address_space *, | |
264 | loff_t, unsigned, unsigned, | |
265 | struct page *, void *); | |
266 | int nobh_truncate_page(struct address_space *, loff_t, get_block_t *); | |
1da177e4 LT |
267 | int nobh_writepage(struct page *page, get_block_t *get_block, |
268 | struct writeback_control *wbc); | |
269 | ||
b6cd0b77 | 270 | void buffer_init(void); |
1da177e4 LT |
271 | |
272 | /* | |
273 | * inline definitions | |
274 | */ | |
275 | ||
1da177e4 LT |
276 | static inline void get_bh(struct buffer_head *bh) |
277 | { | |
278 | atomic_inc(&bh->b_count); | |
279 | } | |
280 | ||
281 | static inline void put_bh(struct buffer_head *bh) | |
282 | { | |
4e857c58 | 283 | smp_mb__before_atomic(); |
1da177e4 LT |
284 | atomic_dec(&bh->b_count); |
285 | } | |
286 | ||
287 | static inline void brelse(struct buffer_head *bh) | |
288 | { | |
289 | if (bh) | |
290 | __brelse(bh); | |
291 | } | |
292 | ||
293 | static inline void bforget(struct buffer_head *bh) | |
294 | { | |
295 | if (bh) | |
296 | __bforget(bh); | |
297 | } | |
298 | ||
299 | static inline struct buffer_head * | |
300 | sb_bread(struct super_block *sb, sector_t block) | |
301 | { | |
3b5e6454 GK |
302 | return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE); |
303 | } | |
304 | ||
305 | static inline struct buffer_head * | |
306 | sb_bread_unmovable(struct super_block *sb, sector_t block) | |
307 | { | |
308 | return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, 0); | |
1da177e4 LT |
309 | } |
310 | ||
311 | static inline void | |
312 | sb_breadahead(struct super_block *sb, sector_t block) | |
313 | { | |
314 | __breadahead(sb->s_bdev, block, sb->s_blocksize); | |
315 | } | |
316 | ||
d87f6392 RG |
317 | static inline void |
318 | sb_breadahead_unmovable(struct super_block *sb, sector_t block) | |
319 | { | |
320 | __breadahead_gfp(sb->s_bdev, block, sb->s_blocksize, 0); | |
321 | } | |
322 | ||
1da177e4 LT |
323 | static inline struct buffer_head * |
324 | sb_getblk(struct super_block *sb, sector_t block) | |
325 | { | |
3b5e6454 | 326 | return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE); |
1da177e4 LT |
327 | } |
328 | ||
bd7ade3c NB |
329 | |
330 | static inline struct buffer_head * | |
331 | sb_getblk_gfp(struct super_block *sb, sector_t block, gfp_t gfp) | |
332 | { | |
333 | return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, gfp); | |
334 | } | |
335 | ||
1da177e4 LT |
336 | static inline struct buffer_head * |
337 | sb_find_get_block(struct super_block *sb, sector_t block) | |
338 | { | |
339 | return __find_get_block(sb->s_bdev, block, sb->s_blocksize); | |
340 | } | |
341 | ||
342 | static inline void | |
343 | map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block) | |
344 | { | |
345 | set_buffer_mapped(bh); | |
346 | bh->b_bdev = sb->s_bdev; | |
347 | bh->b_blocknr = block; | |
b0cf2321 | 348 | bh->b_size = sb->s_blocksize; |
1da177e4 LT |
349 | } |
350 | ||
1da177e4 LT |
351 | static inline void wait_on_buffer(struct buffer_head *bh) |
352 | { | |
353 | might_sleep(); | |
a9877cc2 | 354 | if (buffer_locked(bh)) |
1da177e4 LT |
355 | __wait_on_buffer(bh); |
356 | } | |
357 | ||
ca5de404 NP |
358 | static inline int trylock_buffer(struct buffer_head *bh) |
359 | { | |
51b07fc3 | 360 | return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state)); |
ca5de404 NP |
361 | } |
362 | ||
1da177e4 LT |
363 | static inline void lock_buffer(struct buffer_head *bh) |
364 | { | |
365 | might_sleep(); | |
ca5de404 | 366 | if (!trylock_buffer(bh)) |
1da177e4 LT |
367 | __lock_buffer(bh); |
368 | } | |
369 | ||
3b5e6454 GK |
370 | static inline struct buffer_head *getblk_unmovable(struct block_device *bdev, |
371 | sector_t block, | |
372 | unsigned size) | |
373 | { | |
374 | return __getblk_gfp(bdev, block, size, 0); | |
375 | } | |
376 | ||
377 | static inline struct buffer_head *__getblk(struct block_device *bdev, | |
378 | sector_t block, | |
379 | unsigned size) | |
380 | { | |
381 | return __getblk_gfp(bdev, block, size, __GFP_MOVABLE); | |
382 | } | |
383 | ||
384 | /** | |
385 | * __bread() - reads a specified block and returns the bh | |
386 | * @bdev: the block_device to read from | |
387 | * @block: number of block | |
388 | * @size: size (in bytes) to read | |
389 | * | |
390 | * Reads a specified block, and returns buffer head that contains it. | |
391 | * The page cache is allocated from movable area so that it can be migrated. | |
392 | * It returns NULL if the block was unreadable. | |
393 | */ | |
394 | static inline struct buffer_head * | |
395 | __bread(struct block_device *bdev, sector_t block, unsigned size) | |
396 | { | |
397 | return __bread_gfp(bdev, block, size, __GFP_MOVABLE); | |
398 | } | |
399 | ||
e621900a | 400 | bool block_dirty_folio(struct address_space *mapping, struct folio *folio); |
9361401e DH |
401 | |
402 | #else /* CONFIG_BLOCK */ | |
403 | ||
404 | static inline void buffer_init(void) {} | |
68189fef | 405 | static inline bool try_to_free_buffers(struct folio *folio) { return true; } |
9361401e DH |
406 | static inline int inode_has_buffers(struct inode *inode) { return 0; } |
407 | static inline void invalidate_inode_buffers(struct inode *inode) {} | |
408 | static inline int remove_inode_buffers(struct inode *inode) { return 1; } | |
409 | static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; } | |
243418e3 | 410 | static inline void invalidate_bh_lrus_cpu(void) {} |
6de522d1 | 411 | static inline bool has_bh_in_lru(int cpu, void *dummy) { return false; } |
d2de7ea4 | 412 | #define buffer_heads_over_limit 0 |
9361401e DH |
413 | |
414 | #endif /* CONFIG_BLOCK */ | |
1da177e4 | 415 | #endif /* _LINUX_BUFFER_HEAD_H */ |