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Commit | Line | Data |
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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 */ | |
1da177e4 LT |
39 | |
40 | BH_PrivateStart,/* not a state bit, but the first bit available | |
41 | * for private allocation by other entities | |
42 | */ | |
43 | }; | |
44 | ||
45 | #define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512) | |
46 | ||
47 | struct page; | |
48 | struct buffer_head; | |
49 | struct address_space; | |
50 | typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate); | |
51 | ||
52 | /* | |
205f87f6 BP |
53 | * Historically, a buffer_head was used to map a single block |
54 | * within a page, and of course as the unit of I/O through the | |
55 | * filesystem and block layers. Nowadays the basic I/O unit | |
56 | * is the bio, and buffer_heads are used for extracting block | |
57 | * mappings (via a get_block_t call), for tracking state within | |
58 | * a page (via a page_mapping) and for wrapping bio submission | |
59 | * for backward compatibility reasons (e.g. submit_bh). | |
1da177e4 LT |
60 | */ |
61 | struct buffer_head { | |
1da177e4 LT |
62 | unsigned long b_state; /* buffer state bitmap (see above) */ |
63 | struct buffer_head *b_this_page;/* circular list of page's buffers */ | |
64 | struct page *b_page; /* the page this bh is mapped to */ | |
1da177e4 | 65 | |
205f87f6 BP |
66 | sector_t b_blocknr; /* start block number */ |
67 | size_t b_size; /* size of mapping */ | |
68 | char *b_data; /* pointer to data within the page */ | |
1da177e4 LT |
69 | |
70 | struct block_device *b_bdev; | |
71 | bh_end_io_t *b_end_io; /* I/O completion */ | |
72 | void *b_private; /* reserved for b_end_io */ | |
73 | struct list_head b_assoc_buffers; /* associated with another mapping */ | |
58ff407b JK |
74 | struct address_space *b_assoc_map; /* mapping this buffer is |
75 | associated with */ | |
205f87f6 | 76 | atomic_t b_count; /* users using this buffer_head */ |
1da177e4 LT |
77 | }; |
78 | ||
79 | /* | |
80 | * macro tricks to expand the set_buffer_foo(), clear_buffer_foo() | |
81 | * and buffer_foo() functions. | |
82 | */ | |
83 | #define BUFFER_FNS(bit, name) \ | |
84 | static inline void set_buffer_##name(struct buffer_head *bh) \ | |
85 | { \ | |
86 | set_bit(BH_##bit, &(bh)->b_state); \ | |
87 | } \ | |
88 | static inline void clear_buffer_##name(struct buffer_head *bh) \ | |
89 | { \ | |
90 | clear_bit(BH_##bit, &(bh)->b_state); \ | |
91 | } \ | |
92 | static inline int buffer_##name(const struct buffer_head *bh) \ | |
93 | { \ | |
94 | return test_bit(BH_##bit, &(bh)->b_state); \ | |
95 | } | |
96 | ||
97 | /* | |
98 | * test_set_buffer_foo() and test_clear_buffer_foo() | |
99 | */ | |
100 | #define TAS_BUFFER_FNS(bit, name) \ | |
101 | static inline int test_set_buffer_##name(struct buffer_head *bh) \ | |
102 | { \ | |
103 | return test_and_set_bit(BH_##bit, &(bh)->b_state); \ | |
104 | } \ | |
105 | static inline int test_clear_buffer_##name(struct buffer_head *bh) \ | |
106 | { \ | |
107 | return test_and_clear_bit(BH_##bit, &(bh)->b_state); \ | |
108 | } \ | |
109 | ||
110 | /* | |
111 | * Emit the buffer bitops functions. Note that there are also functions | |
112 | * of the form "mark_buffer_foo()". These are higher-level functions which | |
113 | * do something in addition to setting a b_state bit. | |
114 | */ | |
115 | BUFFER_FNS(Uptodate, uptodate) | |
116 | BUFFER_FNS(Dirty, dirty) | |
117 | TAS_BUFFER_FNS(Dirty, dirty) | |
118 | BUFFER_FNS(Lock, locked) | |
1da177e4 LT |
119 | BUFFER_FNS(Req, req) |
120 | TAS_BUFFER_FNS(Req, req) | |
121 | BUFFER_FNS(Mapped, mapped) | |
122 | BUFFER_FNS(New, new) | |
123 | BUFFER_FNS(Async_Read, async_read) | |
124 | BUFFER_FNS(Async_Write, async_write) | |
125 | BUFFER_FNS(Delay, delay) | |
126 | BUFFER_FNS(Boundary, boundary) | |
127 | BUFFER_FNS(Write_EIO, write_io_error) | |
33a266dd | 128 | BUFFER_FNS(Unwritten, unwritten) |
877f962c TT |
129 | BUFFER_FNS(Meta, meta) |
130 | BUFFER_FNS(Prio, prio) | |
1da177e4 LT |
131 | |
132 | #define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK) | |
1da177e4 LT |
133 | |
134 | /* If we *know* page->private refers to buffer_heads */ | |
135 | #define page_buffers(page) \ | |
136 | ({ \ | |
4c21e2f2 HD |
137 | BUG_ON(!PagePrivate(page)); \ |
138 | ((struct buffer_head *)page_private(page)); \ | |
1da177e4 LT |
139 | }) |
140 | #define page_has_buffers(page) PagePrivate(page) | |
141 | ||
142 | /* | |
143 | * Declarations | |
144 | */ | |
145 | ||
b3c97528 | 146 | void mark_buffer_dirty(struct buffer_head *bh); |
1da177e4 | 147 | void init_buffer(struct buffer_head *, bh_end_io_t *, void *); |
f0059afd | 148 | void touch_buffer(struct buffer_head *bh); |
1da177e4 LT |
149 | void set_bh_page(struct buffer_head *bh, |
150 | struct page *page, unsigned long offset); | |
151 | int try_to_free_buffers(struct page *); | |
152 | struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, | |
153 | int retry); | |
154 | void create_empty_buffers(struct page *, unsigned long, | |
155 | unsigned long b_state); | |
156 | void end_buffer_read_sync(struct buffer_head *bh, int uptodate); | |
157 | void end_buffer_write_sync(struct buffer_head *bh, int uptodate); | |
35c80d5f | 158 | void end_buffer_async_write(struct buffer_head *bh, int uptodate); |
1da177e4 LT |
159 | |
160 | /* Things to do with buffers at mapping->private_list */ | |
161 | void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode); | |
162 | int inode_has_buffers(struct inode *); | |
163 | void invalidate_inode_buffers(struct inode *); | |
164 | int remove_inode_buffers(struct inode *inode); | |
165 | int sync_mapping_buffers(struct address_space *mapping); | |
166 | void unmap_underlying_metadata(struct block_device *bdev, sector_t block); | |
167 | ||
168 | void mark_buffer_async_write(struct buffer_head *bh); | |
1da177e4 LT |
169 | void __wait_on_buffer(struct buffer_head *); |
170 | wait_queue_head_t *bh_waitq_head(struct buffer_head *bh); | |
3991d3bd TK |
171 | struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block, |
172 | unsigned size); | |
173 | struct buffer_head *__getblk(struct block_device *bdev, sector_t block, | |
174 | unsigned size); | |
1da177e4 LT |
175 | void __brelse(struct buffer_head *); |
176 | void __bforget(struct buffer_head *); | |
3991d3bd TK |
177 | void __breadahead(struct block_device *, sector_t block, unsigned int size); |
178 | struct buffer_head *__bread(struct block_device *, sector_t block, unsigned size); | |
f9a14399 | 179 | void invalidate_bh_lrus(void); |
dd0fc66f | 180 | struct buffer_head *alloc_buffer_head(gfp_t gfp_flags); |
1da177e4 | 181 | void free_buffer_head(struct buffer_head * bh); |
b3c97528 HH |
182 | void unlock_buffer(struct buffer_head *bh); |
183 | void __lock_buffer(struct buffer_head *bh); | |
1da177e4 LT |
184 | void ll_rw_block(int, int, struct buffer_head * bh[]); |
185 | int sync_dirty_buffer(struct buffer_head *bh); | |
87e99511 | 186 | int __sync_dirty_buffer(struct buffer_head *bh, int rw); |
9cb569d6 | 187 | void write_dirty_buffer(struct buffer_head *bh, int rw); |
71368511 | 188 | int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags); |
1da177e4 LT |
189 | int submit_bh(int, struct buffer_head *); |
190 | void write_boundary_block(struct block_device *bdev, | |
191 | sector_t bblock, unsigned blocksize); | |
389d1b08 AK |
192 | int bh_uptodate_or_lock(struct buffer_head *bh); |
193 | int bh_submit_read(struct buffer_head *bh); | |
1da177e4 LT |
194 | |
195 | extern int buffer_heads_over_limit; | |
196 | ||
197 | /* | |
198 | * Generic address_space_operations implementations for buffer_head-backed | |
199 | * address_spaces. | |
200 | */ | |
d47992f8 LC |
201 | void block_invalidatepage(struct page *page, unsigned int offset, |
202 | unsigned int length); | |
1da177e4 LT |
203 | int block_write_full_page(struct page *page, get_block_t *get_block, |
204 | struct writeback_control *wbc); | |
35c80d5f CM |
205 | int block_write_full_page_endio(struct page *page, get_block_t *get_block, |
206 | struct writeback_control *wbc, bh_end_io_t *handler); | |
1da177e4 | 207 | int block_read_full_page(struct page*, get_block_t*); |
8ab22b9a HH |
208 | int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc, |
209 | unsigned long from); | |
155130a4 CH |
210 | int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, |
211 | unsigned flags, struct page **pagep, get_block_t *get_block); | |
6e1db88d CH |
212 | int __block_write_begin(struct page *page, loff_t pos, unsigned len, |
213 | get_block_t *get_block); | |
afddba49 NP |
214 | int block_write_end(struct file *, struct address_space *, |
215 | loff_t, unsigned, unsigned, | |
216 | struct page *, void *); | |
217 | int generic_write_end(struct file *, struct address_space *, | |
218 | loff_t, unsigned, unsigned, | |
219 | struct page *, void *); | |
220 | void page_zero_new_buffers(struct page *page, unsigned from, unsigned to); | |
89e10787 NP |
221 | int cont_write_begin(struct file *, struct address_space *, loff_t, |
222 | unsigned, unsigned, struct page **, void **, | |
223 | get_block_t *, loff_t *); | |
05eb0b51 | 224 | int generic_cont_expand_simple(struct inode *inode, loff_t size); |
1da177e4 | 225 | int block_commit_write(struct page *page, unsigned from, unsigned to); |
24da4fab JK |
226 | int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, |
227 | get_block_t get_block); | |
c2ec175c | 228 | int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, |
54171690 | 229 | get_block_t get_block); |
24da4fab JK |
230 | /* Convert errno to return value from ->page_mkwrite() call */ |
231 | static inline int block_page_mkwrite_return(int err) | |
232 | { | |
233 | if (err == 0) | |
234 | return VM_FAULT_LOCKED; | |
235 | if (err == -EFAULT) | |
236 | return VM_FAULT_NOPAGE; | |
237 | if (err == -ENOMEM) | |
238 | return VM_FAULT_OOM; | |
ea13a864 JK |
239 | if (err == -EAGAIN) |
240 | return VM_FAULT_RETRY; | |
24da4fab JK |
241 | /* -ENOSPC, -EDQUOT, -EIO ... */ |
242 | return VM_FAULT_SIGBUS; | |
243 | } | |
1da177e4 | 244 | sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); |
1da177e4 | 245 | int block_truncate_page(struct address_space *, loff_t, get_block_t *); |
ea0f04e5 | 246 | int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned, |
03158cd7 NP |
247 | struct page **, void **, get_block_t*); |
248 | int nobh_write_end(struct file *, struct address_space *, | |
249 | loff_t, unsigned, unsigned, | |
250 | struct page *, void *); | |
251 | int nobh_truncate_page(struct address_space *, loff_t, get_block_t *); | |
1da177e4 LT |
252 | int nobh_writepage(struct page *page, get_block_t *get_block, |
253 | struct writeback_control *wbc); | |
254 | ||
b6cd0b77 | 255 | void buffer_init(void); |
1da177e4 LT |
256 | |
257 | /* | |
258 | * inline definitions | |
259 | */ | |
260 | ||
261 | static inline void attach_page_buffers(struct page *page, | |
262 | struct buffer_head *head) | |
263 | { | |
264 | page_cache_get(page); | |
265 | SetPagePrivate(page); | |
4c21e2f2 | 266 | set_page_private(page, (unsigned long)head); |
1da177e4 LT |
267 | } |
268 | ||
269 | static inline void get_bh(struct buffer_head *bh) | |
270 | { | |
271 | atomic_inc(&bh->b_count); | |
272 | } | |
273 | ||
274 | static inline void put_bh(struct buffer_head *bh) | |
275 | { | |
276 | smp_mb__before_atomic_dec(); | |
277 | atomic_dec(&bh->b_count); | |
278 | } | |
279 | ||
280 | static inline void brelse(struct buffer_head *bh) | |
281 | { | |
282 | if (bh) | |
283 | __brelse(bh); | |
284 | } | |
285 | ||
286 | static inline void bforget(struct buffer_head *bh) | |
287 | { | |
288 | if (bh) | |
289 | __bforget(bh); | |
290 | } | |
291 | ||
292 | static inline struct buffer_head * | |
293 | sb_bread(struct super_block *sb, sector_t block) | |
294 | { | |
295 | return __bread(sb->s_bdev, block, sb->s_blocksize); | |
296 | } | |
297 | ||
298 | static inline void | |
299 | sb_breadahead(struct super_block *sb, sector_t block) | |
300 | { | |
301 | __breadahead(sb->s_bdev, block, sb->s_blocksize); | |
302 | } | |
303 | ||
304 | static inline struct buffer_head * | |
305 | sb_getblk(struct super_block *sb, sector_t block) | |
306 | { | |
307 | return __getblk(sb->s_bdev, block, sb->s_blocksize); | |
308 | } | |
309 | ||
310 | static inline struct buffer_head * | |
311 | sb_find_get_block(struct super_block *sb, sector_t block) | |
312 | { | |
313 | return __find_get_block(sb->s_bdev, block, sb->s_blocksize); | |
314 | } | |
315 | ||
316 | static inline void | |
317 | map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block) | |
318 | { | |
319 | set_buffer_mapped(bh); | |
320 | bh->b_bdev = sb->s_bdev; | |
321 | bh->b_blocknr = block; | |
b0cf2321 | 322 | bh->b_size = sb->s_blocksize; |
1da177e4 LT |
323 | } |
324 | ||
1da177e4 LT |
325 | static inline void wait_on_buffer(struct buffer_head *bh) |
326 | { | |
327 | might_sleep(); | |
a9877cc2 | 328 | if (buffer_locked(bh)) |
1da177e4 LT |
329 | __wait_on_buffer(bh); |
330 | } | |
331 | ||
ca5de404 NP |
332 | static inline int trylock_buffer(struct buffer_head *bh) |
333 | { | |
51b07fc3 | 334 | return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state)); |
ca5de404 NP |
335 | } |
336 | ||
1da177e4 LT |
337 | static inline void lock_buffer(struct buffer_head *bh) |
338 | { | |
339 | might_sleep(); | |
ca5de404 | 340 | if (!trylock_buffer(bh)) |
1da177e4 LT |
341 | __lock_buffer(bh); |
342 | } | |
343 | ||
cf9a2ae8 | 344 | extern int __set_page_dirty_buffers(struct page *page); |
9361401e DH |
345 | |
346 | #else /* CONFIG_BLOCK */ | |
347 | ||
348 | static inline void buffer_init(void) {} | |
349 | static inline int try_to_free_buffers(struct page *page) { return 1; } | |
9361401e DH |
350 | static inline int inode_has_buffers(struct inode *inode) { return 0; } |
351 | static inline void invalidate_inode_buffers(struct inode *inode) {} | |
352 | static inline int remove_inode_buffers(struct inode *inode) { return 1; } | |
353 | static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; } | |
9361401e DH |
354 | |
355 | #endif /* CONFIG_BLOCK */ | |
1da177e4 | 356 | #endif /* _LINUX_BUFFER_HEAD_H */ |