Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * include/linux/buffer_head.h | |
3 | * | |
4 | * Everything to do with buffer_heads. | |
5 | */ | |
6 | ||
7 | #ifndef _LINUX_BUFFER_HEAD_H | |
8 | #define _LINUX_BUFFER_HEAD_H | |
9 | ||
10 | #include <linux/types.h> | |
11 | #include <linux/fs.h> | |
12 | #include <linux/linkage.h> | |
13 | #include <linux/pagemap.h> | |
14 | #include <linux/wait.h> | |
60063497 | 15 | #include <linux/atomic.h> |
1da177e4 | 16 | |
9361401e DH |
17 | #ifdef CONFIG_BLOCK |
18 | ||
1da177e4 LT |
19 | enum bh_state_bits { |
20 | BH_Uptodate, /* Contains valid data */ | |
21 | BH_Dirty, /* Is dirty */ | |
22 | BH_Lock, /* Is locked */ | |
23 | BH_Req, /* Has been submitted for I/O */ | |
a3972203 NP |
24 | BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise |
25 | * IO completion of other buffers in the page | |
26 | */ | |
1da177e4 LT |
27 | |
28 | BH_Mapped, /* Has a disk mapping */ | |
29 | BH_New, /* Disk mapping was newly created by get_block */ | |
30 | BH_Async_Read, /* Is under end_buffer_async_read I/O */ | |
31 | BH_Async_Write, /* Is under end_buffer_async_write I/O */ | |
32 | BH_Delay, /* Buffer is not yet allocated on disk */ | |
33 | BH_Boundary, /* Block is followed by a discontiguity */ | |
34 | BH_Write_EIO, /* I/O error on write */ | |
33a266dd | 35 | BH_Unwritten, /* Buffer is allocated on disk but not written */ |
08bafc03 | 36 | BH_Quiet, /* Buffer Error Prinks to be quiet */ |
877f962c TT |
37 | BH_Meta, /* Buffer contains metadata */ |
38 | BH_Prio, /* Buffer should be submitted with REQ_PRIO */ | |
7b7a8665 | 39 | BH_Defer_Completion, /* Defer AIO completion to workqueue */ |
1da177e4 LT |
40 | |
41 | BH_PrivateStart,/* not a state bit, but the first bit available | |
42 | * for private allocation by other entities | |
43 | */ | |
44 | }; | |
45 | ||
46 | #define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512) | |
47 | ||
48 | struct page; | |
49 | struct buffer_head; | |
50 | struct address_space; | |
51 | typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate); | |
52 | ||
53 | /* | |
205f87f6 BP |
54 | * Historically, a buffer_head was used to map a single block |
55 | * within a page, and of course as the unit of I/O through the | |
56 | * filesystem and block layers. Nowadays the basic I/O unit | |
57 | * is the bio, and buffer_heads are used for extracting block | |
58 | * mappings (via a get_block_t call), for tracking state within | |
59 | * a page (via a page_mapping) and for wrapping bio submission | |
60 | * for backward compatibility reasons (e.g. submit_bh). | |
1da177e4 LT |
61 | */ |
62 | struct buffer_head { | |
1da177e4 LT |
63 | unsigned long b_state; /* buffer state bitmap (see above) */ |
64 | struct buffer_head *b_this_page;/* circular list of page's buffers */ | |
65 | struct page *b_page; /* the page this bh is mapped to */ | |
1da177e4 | 66 | |
205f87f6 BP |
67 | sector_t b_blocknr; /* start block number */ |
68 | size_t b_size; /* size of mapping */ | |
69 | char *b_data; /* pointer to data within the page */ | |
1da177e4 LT |
70 | |
71 | struct block_device *b_bdev; | |
72 | bh_end_io_t *b_end_io; /* I/O completion */ | |
73 | void *b_private; /* reserved for b_end_io */ | |
74 | struct list_head b_assoc_buffers; /* associated with another mapping */ | |
58ff407b JK |
75 | struct address_space *b_assoc_map; /* mapping this buffer is |
76 | associated with */ | |
205f87f6 | 77 | atomic_t b_count; /* users using this buffer_head */ |
1da177e4 LT |
78 | }; |
79 | ||
80 | /* | |
81 | * macro tricks to expand the set_buffer_foo(), clear_buffer_foo() | |
82 | * and buffer_foo() functions. | |
83 | */ | |
84 | #define BUFFER_FNS(bit, name) \ | |
85 | static inline void set_buffer_##name(struct buffer_head *bh) \ | |
86 | { \ | |
87 | set_bit(BH_##bit, &(bh)->b_state); \ | |
88 | } \ | |
89 | static inline void clear_buffer_##name(struct buffer_head *bh) \ | |
90 | { \ | |
91 | clear_bit(BH_##bit, &(bh)->b_state); \ | |
92 | } \ | |
93 | static inline int buffer_##name(const struct buffer_head *bh) \ | |
94 | { \ | |
95 | return test_bit(BH_##bit, &(bh)->b_state); \ | |
96 | } | |
97 | ||
98 | /* | |
99 | * test_set_buffer_foo() and test_clear_buffer_foo() | |
100 | */ | |
101 | #define TAS_BUFFER_FNS(bit, name) \ | |
102 | static inline int test_set_buffer_##name(struct buffer_head *bh) \ | |
103 | { \ | |
104 | return test_and_set_bit(BH_##bit, &(bh)->b_state); \ | |
105 | } \ | |
106 | static inline int test_clear_buffer_##name(struct buffer_head *bh) \ | |
107 | { \ | |
108 | return test_and_clear_bit(BH_##bit, &(bh)->b_state); \ | |
109 | } \ | |
110 | ||
111 | /* | |
112 | * Emit the buffer bitops functions. Note that there are also functions | |
113 | * of the form "mark_buffer_foo()". These are higher-level functions which | |
114 | * do something in addition to setting a b_state bit. | |
115 | */ | |
116 | BUFFER_FNS(Uptodate, uptodate) | |
117 | BUFFER_FNS(Dirty, dirty) | |
118 | TAS_BUFFER_FNS(Dirty, dirty) | |
119 | BUFFER_FNS(Lock, locked) | |
1da177e4 LT |
120 | BUFFER_FNS(Req, req) |
121 | TAS_BUFFER_FNS(Req, req) | |
122 | BUFFER_FNS(Mapped, mapped) | |
123 | BUFFER_FNS(New, new) | |
124 | BUFFER_FNS(Async_Read, async_read) | |
125 | BUFFER_FNS(Async_Write, async_write) | |
126 | BUFFER_FNS(Delay, delay) | |
127 | BUFFER_FNS(Boundary, boundary) | |
128 | BUFFER_FNS(Write_EIO, write_io_error) | |
33a266dd | 129 | BUFFER_FNS(Unwritten, unwritten) |
877f962c TT |
130 | BUFFER_FNS(Meta, meta) |
131 | BUFFER_FNS(Prio, prio) | |
7b7a8665 | 132 | BUFFER_FNS(Defer_Completion, defer_completion) |
1da177e4 LT |
133 | |
134 | #define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK) | |
1da177e4 LT |
135 | |
136 | /* If we *know* page->private refers to buffer_heads */ | |
137 | #define page_buffers(page) \ | |
138 | ({ \ | |
4c21e2f2 HD |
139 | BUG_ON(!PagePrivate(page)); \ |
140 | ((struct buffer_head *)page_private(page)); \ | |
1da177e4 LT |
141 | }) |
142 | #define page_has_buffers(page) PagePrivate(page) | |
143 | ||
b4597226 MG |
144 | void buffer_check_dirty_writeback(struct page *page, |
145 | bool *dirty, bool *writeback); | |
146 | ||
1da177e4 LT |
147 | /* |
148 | * Declarations | |
149 | */ | |
150 | ||
b3c97528 | 151 | void mark_buffer_dirty(struct buffer_head *bh); |
1da177e4 | 152 | void init_buffer(struct buffer_head *, bh_end_io_t *, void *); |
f0059afd | 153 | void touch_buffer(struct buffer_head *bh); |
1da177e4 LT |
154 | void set_bh_page(struct buffer_head *bh, |
155 | struct page *page, unsigned long offset); | |
156 | int try_to_free_buffers(struct page *); | |
157 | struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, | |
158 | int retry); | |
159 | void create_empty_buffers(struct page *, unsigned long, | |
160 | unsigned long b_state); | |
161 | void end_buffer_read_sync(struct buffer_head *bh, int uptodate); | |
162 | void end_buffer_write_sync(struct buffer_head *bh, int uptodate); | |
35c80d5f | 163 | void end_buffer_async_write(struct buffer_head *bh, int uptodate); |
1da177e4 LT |
164 | |
165 | /* Things to do with buffers at mapping->private_list */ | |
166 | void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode); | |
167 | int inode_has_buffers(struct inode *); | |
168 | void invalidate_inode_buffers(struct inode *); | |
169 | int remove_inode_buffers(struct inode *inode); | |
170 | int sync_mapping_buffers(struct address_space *mapping); | |
171 | void unmap_underlying_metadata(struct block_device *bdev, sector_t block); | |
172 | ||
173 | void mark_buffer_async_write(struct buffer_head *bh); | |
1da177e4 LT |
174 | void __wait_on_buffer(struct buffer_head *); |
175 | wait_queue_head_t *bh_waitq_head(struct buffer_head *bh); | |
3991d3bd TK |
176 | struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block, |
177 | unsigned size); | |
178 | struct buffer_head *__getblk(struct block_device *bdev, sector_t block, | |
179 | unsigned size); | |
1da177e4 LT |
180 | void __brelse(struct buffer_head *); |
181 | void __bforget(struct buffer_head *); | |
3991d3bd TK |
182 | void __breadahead(struct block_device *, sector_t block, unsigned int size); |
183 | struct buffer_head *__bread(struct block_device *, sector_t block, unsigned size); | |
f9a14399 | 184 | void invalidate_bh_lrus(void); |
dd0fc66f | 185 | struct buffer_head *alloc_buffer_head(gfp_t gfp_flags); |
1da177e4 | 186 | void free_buffer_head(struct buffer_head * bh); |
b3c97528 HH |
187 | void unlock_buffer(struct buffer_head *bh); |
188 | void __lock_buffer(struct buffer_head *bh); | |
1da177e4 LT |
189 | void ll_rw_block(int, int, struct buffer_head * bh[]); |
190 | int sync_dirty_buffer(struct buffer_head *bh); | |
87e99511 | 191 | int __sync_dirty_buffer(struct buffer_head *bh, int rw); |
9cb569d6 | 192 | void write_dirty_buffer(struct buffer_head *bh, int rw); |
71368511 | 193 | int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags); |
1da177e4 LT |
194 | int submit_bh(int, struct buffer_head *); |
195 | void write_boundary_block(struct block_device *bdev, | |
196 | sector_t bblock, unsigned blocksize); | |
389d1b08 AK |
197 | int bh_uptodate_or_lock(struct buffer_head *bh); |
198 | int bh_submit_read(struct buffer_head *bh); | |
1da177e4 LT |
199 | |
200 | extern int buffer_heads_over_limit; | |
201 | ||
202 | /* | |
203 | * Generic address_space_operations implementations for buffer_head-backed | |
204 | * address_spaces. | |
205 | */ | |
d47992f8 LC |
206 | void block_invalidatepage(struct page *page, unsigned int offset, |
207 | unsigned int length); | |
1da177e4 LT |
208 | int block_write_full_page(struct page *page, get_block_t *get_block, |
209 | struct writeback_control *wbc); | |
210 | int block_read_full_page(struct page*, get_block_t*); | |
c186afb4 AV |
211 | int block_is_partially_uptodate(struct page *page, unsigned long from, |
212 | unsigned long count); | |
155130a4 CH |
213 | int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, |
214 | unsigned flags, struct page **pagep, get_block_t *get_block); | |
6e1db88d CH |
215 | int __block_write_begin(struct page *page, loff_t pos, unsigned len, |
216 | get_block_t *get_block); | |
afddba49 NP |
217 | int block_write_end(struct file *, struct address_space *, |
218 | loff_t, unsigned, unsigned, | |
219 | struct page *, void *); | |
220 | int generic_write_end(struct file *, struct address_space *, | |
221 | loff_t, unsigned, unsigned, | |
222 | struct page *, void *); | |
223 | void page_zero_new_buffers(struct page *page, unsigned from, unsigned to); | |
89e10787 NP |
224 | int cont_write_begin(struct file *, struct address_space *, loff_t, |
225 | unsigned, unsigned, struct page **, void **, | |
226 | get_block_t *, loff_t *); | |
05eb0b51 | 227 | int generic_cont_expand_simple(struct inode *inode, loff_t size); |
1da177e4 | 228 | int block_commit_write(struct page *page, unsigned from, unsigned to); |
24da4fab JK |
229 | int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, |
230 | get_block_t get_block); | |
c2ec175c | 231 | int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, |
54171690 | 232 | get_block_t get_block); |
24da4fab JK |
233 | /* Convert errno to return value from ->page_mkwrite() call */ |
234 | static inline int block_page_mkwrite_return(int err) | |
235 | { | |
236 | if (err == 0) | |
237 | return VM_FAULT_LOCKED; | |
238 | if (err == -EFAULT) | |
239 | return VM_FAULT_NOPAGE; | |
240 | if (err == -ENOMEM) | |
241 | return VM_FAULT_OOM; | |
ea13a864 JK |
242 | if (err == -EAGAIN) |
243 | return VM_FAULT_RETRY; | |
24da4fab JK |
244 | /* -ENOSPC, -EDQUOT, -EIO ... */ |
245 | return VM_FAULT_SIGBUS; | |
246 | } | |
1da177e4 | 247 | sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); |
1da177e4 | 248 | int block_truncate_page(struct address_space *, loff_t, get_block_t *); |
ea0f04e5 | 249 | int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned, |
03158cd7 NP |
250 | struct page **, void **, get_block_t*); |
251 | int nobh_write_end(struct file *, struct address_space *, | |
252 | loff_t, unsigned, unsigned, | |
253 | struct page *, void *); | |
254 | int nobh_truncate_page(struct address_space *, loff_t, get_block_t *); | |
1da177e4 LT |
255 | int nobh_writepage(struct page *page, get_block_t *get_block, |
256 | struct writeback_control *wbc); | |
257 | ||
b6cd0b77 | 258 | void buffer_init(void); |
1da177e4 LT |
259 | |
260 | /* | |
261 | * inline definitions | |
262 | */ | |
263 | ||
264 | static inline void attach_page_buffers(struct page *page, | |
265 | struct buffer_head *head) | |
266 | { | |
267 | page_cache_get(page); | |
268 | SetPagePrivate(page); | |
4c21e2f2 | 269 | set_page_private(page, (unsigned long)head); |
1da177e4 LT |
270 | } |
271 | ||
272 | static inline void get_bh(struct buffer_head *bh) | |
273 | { | |
274 | atomic_inc(&bh->b_count); | |
275 | } | |
276 | ||
277 | static inline void put_bh(struct buffer_head *bh) | |
278 | { | |
4e857c58 | 279 | smp_mb__before_atomic(); |
1da177e4 LT |
280 | atomic_dec(&bh->b_count); |
281 | } | |
282 | ||
283 | static inline void brelse(struct buffer_head *bh) | |
284 | { | |
285 | if (bh) | |
286 | __brelse(bh); | |
287 | } | |
288 | ||
289 | static inline void bforget(struct buffer_head *bh) | |
290 | { | |
291 | if (bh) | |
292 | __bforget(bh); | |
293 | } | |
294 | ||
295 | static inline struct buffer_head * | |
296 | sb_bread(struct super_block *sb, sector_t block) | |
297 | { | |
298 | return __bread(sb->s_bdev, block, sb->s_blocksize); | |
299 | } | |
300 | ||
301 | static inline void | |
302 | sb_breadahead(struct super_block *sb, sector_t block) | |
303 | { | |
304 | __breadahead(sb->s_bdev, block, sb->s_blocksize); | |
305 | } | |
306 | ||
307 | static inline struct buffer_head * | |
308 | sb_getblk(struct super_block *sb, sector_t block) | |
309 | { | |
310 | return __getblk(sb->s_bdev, block, sb->s_blocksize); | |
311 | } | |
312 | ||
313 | static inline struct buffer_head * | |
314 | sb_find_get_block(struct super_block *sb, sector_t block) | |
315 | { | |
316 | return __find_get_block(sb->s_bdev, block, sb->s_blocksize); | |
317 | } | |
318 | ||
319 | static inline void | |
320 | map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block) | |
321 | { | |
322 | set_buffer_mapped(bh); | |
323 | bh->b_bdev = sb->s_bdev; | |
324 | bh->b_blocknr = block; | |
b0cf2321 | 325 | bh->b_size = sb->s_blocksize; |
1da177e4 LT |
326 | } |
327 | ||
1da177e4 LT |
328 | static inline void wait_on_buffer(struct buffer_head *bh) |
329 | { | |
330 | might_sleep(); | |
a9877cc2 | 331 | if (buffer_locked(bh)) |
1da177e4 LT |
332 | __wait_on_buffer(bh); |
333 | } | |
334 | ||
ca5de404 NP |
335 | static inline int trylock_buffer(struct buffer_head *bh) |
336 | { | |
51b07fc3 | 337 | return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state)); |
ca5de404 NP |
338 | } |
339 | ||
1da177e4 LT |
340 | static inline void lock_buffer(struct buffer_head *bh) |
341 | { | |
342 | might_sleep(); | |
ca5de404 | 343 | if (!trylock_buffer(bh)) |
1da177e4 LT |
344 | __lock_buffer(bh); |
345 | } | |
346 | ||
cf9a2ae8 | 347 | extern int __set_page_dirty_buffers(struct page *page); |
9361401e DH |
348 | |
349 | #else /* CONFIG_BLOCK */ | |
350 | ||
351 | static inline void buffer_init(void) {} | |
352 | static inline int try_to_free_buffers(struct page *page) { return 1; } | |
9361401e DH |
353 | static inline int inode_has_buffers(struct inode *inode) { return 0; } |
354 | static inline void invalidate_inode_buffers(struct inode *inode) {} | |
355 | static inline int remove_inode_buffers(struct inode *inode) { return 1; } | |
356 | static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; } | |
9361401e DH |
357 | |
358 | #endif /* CONFIG_BLOCK */ | |
1da177e4 | 359 | #endif /* _LINUX_BUFFER_HEAD_H */ |