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> | |
15 | #include <asm/atomic.h> | |
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 */ |
1da177e4 LT |
37 | |
38 | BH_PrivateStart,/* not a state bit, but the first bit available | |
39 | * for private allocation by other entities | |
40 | */ | |
41 | }; | |
42 | ||
43 | #define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512) | |
44 | ||
45 | struct page; | |
46 | struct buffer_head; | |
47 | struct address_space; | |
48 | typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate); | |
49 | ||
50 | /* | |
205f87f6 BP |
51 | * Historically, a buffer_head was used to map a single block |
52 | * within a page, and of course as the unit of I/O through the | |
53 | * filesystem and block layers. Nowadays the basic I/O unit | |
54 | * is the bio, and buffer_heads are used for extracting block | |
55 | * mappings (via a get_block_t call), for tracking state within | |
56 | * a page (via a page_mapping) and for wrapping bio submission | |
57 | * for backward compatibility reasons (e.g. submit_bh). | |
1da177e4 LT |
58 | */ |
59 | struct buffer_head { | |
1da177e4 LT |
60 | unsigned long b_state; /* buffer state bitmap (see above) */ |
61 | struct buffer_head *b_this_page;/* circular list of page's buffers */ | |
62 | struct page *b_page; /* the page this bh is mapped to */ | |
1da177e4 | 63 | |
205f87f6 BP |
64 | sector_t b_blocknr; /* start block number */ |
65 | size_t b_size; /* size of mapping */ | |
66 | char *b_data; /* pointer to data within the page */ | |
1da177e4 LT |
67 | |
68 | struct block_device *b_bdev; | |
69 | bh_end_io_t *b_end_io; /* I/O completion */ | |
70 | void *b_private; /* reserved for b_end_io */ | |
71 | struct list_head b_assoc_buffers; /* associated with another mapping */ | |
58ff407b JK |
72 | struct address_space *b_assoc_map; /* mapping this buffer is |
73 | associated with */ | |
205f87f6 | 74 | atomic_t b_count; /* users using this buffer_head */ |
1da177e4 LT |
75 | }; |
76 | ||
77 | /* | |
78 | * macro tricks to expand the set_buffer_foo(), clear_buffer_foo() | |
79 | * and buffer_foo() functions. | |
80 | */ | |
81 | #define BUFFER_FNS(bit, name) \ | |
82 | static inline void set_buffer_##name(struct buffer_head *bh) \ | |
83 | { \ | |
84 | set_bit(BH_##bit, &(bh)->b_state); \ | |
85 | } \ | |
86 | static inline void clear_buffer_##name(struct buffer_head *bh) \ | |
87 | { \ | |
88 | clear_bit(BH_##bit, &(bh)->b_state); \ | |
89 | } \ | |
90 | static inline int buffer_##name(const struct buffer_head *bh) \ | |
91 | { \ | |
92 | return test_bit(BH_##bit, &(bh)->b_state); \ | |
93 | } | |
94 | ||
95 | /* | |
96 | * test_set_buffer_foo() and test_clear_buffer_foo() | |
97 | */ | |
98 | #define TAS_BUFFER_FNS(bit, name) \ | |
99 | static inline int test_set_buffer_##name(struct buffer_head *bh) \ | |
100 | { \ | |
101 | return test_and_set_bit(BH_##bit, &(bh)->b_state); \ | |
102 | } \ | |
103 | static inline int test_clear_buffer_##name(struct buffer_head *bh) \ | |
104 | { \ | |
105 | return test_and_clear_bit(BH_##bit, &(bh)->b_state); \ | |
106 | } \ | |
107 | ||
108 | /* | |
109 | * Emit the buffer bitops functions. Note that there are also functions | |
110 | * of the form "mark_buffer_foo()". These are higher-level functions which | |
111 | * do something in addition to setting a b_state bit. | |
112 | */ | |
113 | BUFFER_FNS(Uptodate, uptodate) | |
114 | BUFFER_FNS(Dirty, dirty) | |
115 | TAS_BUFFER_FNS(Dirty, dirty) | |
116 | BUFFER_FNS(Lock, locked) | |
1da177e4 LT |
117 | BUFFER_FNS(Req, req) |
118 | TAS_BUFFER_FNS(Req, req) | |
119 | BUFFER_FNS(Mapped, mapped) | |
120 | BUFFER_FNS(New, new) | |
121 | BUFFER_FNS(Async_Read, async_read) | |
122 | BUFFER_FNS(Async_Write, async_write) | |
123 | BUFFER_FNS(Delay, delay) | |
124 | BUFFER_FNS(Boundary, boundary) | |
125 | BUFFER_FNS(Write_EIO, write_io_error) | |
33a266dd | 126 | BUFFER_FNS(Unwritten, unwritten) |
1da177e4 LT |
127 | |
128 | #define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK) | |
129 | #define touch_buffer(bh) mark_page_accessed(bh->b_page) | |
130 | ||
131 | /* If we *know* page->private refers to buffer_heads */ | |
132 | #define page_buffers(page) \ | |
133 | ({ \ | |
4c21e2f2 HD |
134 | BUG_ON(!PagePrivate(page)); \ |
135 | ((struct buffer_head *)page_private(page)); \ | |
1da177e4 LT |
136 | }) |
137 | #define page_has_buffers(page) PagePrivate(page) | |
138 | ||
139 | /* | |
140 | * Declarations | |
141 | */ | |
142 | ||
b3c97528 | 143 | void mark_buffer_dirty(struct buffer_head *bh); |
1da177e4 LT |
144 | void init_buffer(struct buffer_head *, bh_end_io_t *, void *); |
145 | void set_bh_page(struct buffer_head *bh, | |
146 | struct page *page, unsigned long offset); | |
147 | int try_to_free_buffers(struct page *); | |
148 | struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, | |
149 | int retry); | |
150 | void create_empty_buffers(struct page *, unsigned long, | |
151 | unsigned long b_state); | |
152 | void end_buffer_read_sync(struct buffer_head *bh, int uptodate); | |
153 | void end_buffer_write_sync(struct buffer_head *bh, int uptodate); | |
35c80d5f | 154 | void end_buffer_async_write(struct buffer_head *bh, int uptodate); |
1da177e4 LT |
155 | |
156 | /* Things to do with buffers at mapping->private_list */ | |
157 | void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode); | |
158 | int inode_has_buffers(struct inode *); | |
159 | void invalidate_inode_buffers(struct inode *); | |
160 | int remove_inode_buffers(struct inode *inode); | |
161 | int sync_mapping_buffers(struct address_space *mapping); | |
162 | void unmap_underlying_metadata(struct block_device *bdev, sector_t block); | |
163 | ||
164 | void mark_buffer_async_write(struct buffer_head *bh); | |
1da177e4 LT |
165 | void __wait_on_buffer(struct buffer_head *); |
166 | wait_queue_head_t *bh_waitq_head(struct buffer_head *bh); | |
3991d3bd TK |
167 | struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block, |
168 | unsigned size); | |
169 | struct buffer_head *__getblk(struct block_device *bdev, sector_t block, | |
170 | unsigned size); | |
1da177e4 LT |
171 | void __brelse(struct buffer_head *); |
172 | void __bforget(struct buffer_head *); | |
3991d3bd TK |
173 | void __breadahead(struct block_device *, sector_t block, unsigned int size); |
174 | struct buffer_head *__bread(struct block_device *, sector_t block, unsigned size); | |
f9a14399 | 175 | void invalidate_bh_lrus(void); |
dd0fc66f | 176 | struct buffer_head *alloc_buffer_head(gfp_t gfp_flags); |
1da177e4 | 177 | void free_buffer_head(struct buffer_head * bh); |
b3c97528 HH |
178 | void unlock_buffer(struct buffer_head *bh); |
179 | void __lock_buffer(struct buffer_head *bh); | |
1da177e4 LT |
180 | void ll_rw_block(int, int, struct buffer_head * bh[]); |
181 | int sync_dirty_buffer(struct buffer_head *bh); | |
87e99511 | 182 | int __sync_dirty_buffer(struct buffer_head *bh, int rw); |
9cb569d6 | 183 | void write_dirty_buffer(struct buffer_head *bh, int rw); |
1da177e4 LT |
184 | int submit_bh(int, struct buffer_head *); |
185 | void write_boundary_block(struct block_device *bdev, | |
186 | sector_t bblock, unsigned blocksize); | |
389d1b08 AK |
187 | int bh_uptodate_or_lock(struct buffer_head *bh); |
188 | int bh_submit_read(struct buffer_head *bh); | |
1da177e4 LT |
189 | |
190 | extern int buffer_heads_over_limit; | |
191 | ||
192 | /* | |
193 | * Generic address_space_operations implementations for buffer_head-backed | |
194 | * address_spaces. | |
195 | */ | |
2ff28e22 | 196 | void block_invalidatepage(struct page *page, unsigned long offset); |
1da177e4 LT |
197 | int block_write_full_page(struct page *page, get_block_t *get_block, |
198 | struct writeback_control *wbc); | |
35c80d5f CM |
199 | int block_write_full_page_endio(struct page *page, get_block_t *get_block, |
200 | struct writeback_control *wbc, bh_end_io_t *handler); | |
1da177e4 | 201 | int block_read_full_page(struct page*, get_block_t*); |
8ab22b9a HH |
202 | int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc, |
203 | unsigned long from); | |
155130a4 CH |
204 | int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, |
205 | unsigned flags, struct page **pagep, get_block_t *get_block); | |
6e1db88d CH |
206 | int __block_write_begin(struct page *page, loff_t pos, unsigned len, |
207 | get_block_t *get_block); | |
afddba49 NP |
208 | int block_write_end(struct file *, struct address_space *, |
209 | loff_t, unsigned, unsigned, | |
210 | struct page *, void *); | |
211 | int generic_write_end(struct file *, struct address_space *, | |
212 | loff_t, unsigned, unsigned, | |
213 | struct page *, void *); | |
214 | void page_zero_new_buffers(struct page *page, unsigned from, unsigned to); | |
89e10787 NP |
215 | int cont_write_begin(struct file *, struct address_space *, loff_t, |
216 | unsigned, unsigned, struct page **, void **, | |
217 | get_block_t *, loff_t *); | |
05eb0b51 | 218 | int generic_cont_expand_simple(struct inode *inode, loff_t size); |
1da177e4 | 219 | int block_commit_write(struct page *page, unsigned from, unsigned to); |
c2ec175c | 220 | int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, |
54171690 | 221 | get_block_t get_block); |
1da177e4 | 222 | sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); |
1da177e4 | 223 | int block_truncate_page(struct address_space *, loff_t, get_block_t *); |
ea0f04e5 | 224 | int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned, |
03158cd7 NP |
225 | struct page **, void **, get_block_t*); |
226 | int nobh_write_end(struct file *, struct address_space *, | |
227 | loff_t, unsigned, unsigned, | |
228 | struct page *, void *); | |
229 | int nobh_truncate_page(struct address_space *, loff_t, get_block_t *); | |
1da177e4 LT |
230 | int nobh_writepage(struct page *page, get_block_t *get_block, |
231 | struct writeback_control *wbc); | |
232 | ||
b6cd0b77 | 233 | void buffer_init(void); |
1da177e4 LT |
234 | |
235 | /* | |
236 | * inline definitions | |
237 | */ | |
238 | ||
239 | static inline void attach_page_buffers(struct page *page, | |
240 | struct buffer_head *head) | |
241 | { | |
242 | page_cache_get(page); | |
243 | SetPagePrivate(page); | |
4c21e2f2 | 244 | set_page_private(page, (unsigned long)head); |
1da177e4 LT |
245 | } |
246 | ||
247 | static inline void get_bh(struct buffer_head *bh) | |
248 | { | |
249 | atomic_inc(&bh->b_count); | |
250 | } | |
251 | ||
252 | static inline void put_bh(struct buffer_head *bh) | |
253 | { | |
254 | smp_mb__before_atomic_dec(); | |
255 | atomic_dec(&bh->b_count); | |
256 | } | |
257 | ||
258 | static inline void brelse(struct buffer_head *bh) | |
259 | { | |
260 | if (bh) | |
261 | __brelse(bh); | |
262 | } | |
263 | ||
264 | static inline void bforget(struct buffer_head *bh) | |
265 | { | |
266 | if (bh) | |
267 | __bforget(bh); | |
268 | } | |
269 | ||
270 | static inline struct buffer_head * | |
271 | sb_bread(struct super_block *sb, sector_t block) | |
272 | { | |
273 | return __bread(sb->s_bdev, block, sb->s_blocksize); | |
274 | } | |
275 | ||
276 | static inline void | |
277 | sb_breadahead(struct super_block *sb, sector_t block) | |
278 | { | |
279 | __breadahead(sb->s_bdev, block, sb->s_blocksize); | |
280 | } | |
281 | ||
282 | static inline struct buffer_head * | |
283 | sb_getblk(struct super_block *sb, sector_t block) | |
284 | { | |
285 | return __getblk(sb->s_bdev, block, sb->s_blocksize); | |
286 | } | |
287 | ||
288 | static inline struct buffer_head * | |
289 | sb_find_get_block(struct super_block *sb, sector_t block) | |
290 | { | |
291 | return __find_get_block(sb->s_bdev, block, sb->s_blocksize); | |
292 | } | |
293 | ||
294 | static inline void | |
295 | map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block) | |
296 | { | |
297 | set_buffer_mapped(bh); | |
298 | bh->b_bdev = sb->s_bdev; | |
299 | bh->b_blocknr = block; | |
b0cf2321 | 300 | bh->b_size = sb->s_blocksize; |
1da177e4 LT |
301 | } |
302 | ||
1da177e4 LT |
303 | static inline void wait_on_buffer(struct buffer_head *bh) |
304 | { | |
305 | might_sleep(); | |
a9877cc2 | 306 | if (buffer_locked(bh)) |
1da177e4 LT |
307 | __wait_on_buffer(bh); |
308 | } | |
309 | ||
ca5de404 NP |
310 | static inline int trylock_buffer(struct buffer_head *bh) |
311 | { | |
51b07fc3 | 312 | return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state)); |
ca5de404 NP |
313 | } |
314 | ||
1da177e4 LT |
315 | static inline void lock_buffer(struct buffer_head *bh) |
316 | { | |
317 | might_sleep(); | |
ca5de404 | 318 | if (!trylock_buffer(bh)) |
1da177e4 LT |
319 | __lock_buffer(bh); |
320 | } | |
321 | ||
cf9a2ae8 | 322 | extern int __set_page_dirty_buffers(struct page *page); |
9361401e DH |
323 | |
324 | #else /* CONFIG_BLOCK */ | |
325 | ||
326 | static inline void buffer_init(void) {} | |
327 | static inline int try_to_free_buffers(struct page *page) { return 1; } | |
9361401e DH |
328 | static inline int inode_has_buffers(struct inode *inode) { return 0; } |
329 | static inline void invalidate_inode_buffers(struct inode *inode) {} | |
330 | static inline int remove_inode_buffers(struct inode *inode) { return 1; } | |
331 | static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; } | |
9361401e DH |
332 | |
333 | #endif /* CONFIG_BLOCK */ | |
1da177e4 | 334 | #endif /* _LINUX_BUFFER_HEAD_H */ |