1
2
3
4
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
17#ifdef CONFIG_BLOCK
18
19enum bh_state_bits {
20 BH_Uptodate,
21 BH_Dirty,
22 BH_Lock,
23 BH_Req,
24 BH_Uptodate_Lock,
25
26
27
28 BH_Mapped,
29 BH_New,
30 BH_Async_Read,
31 BH_Async_Write,
32 BH_Delay,
33 BH_Boundary,
34 BH_Write_EIO,
35 BH_Ordered,
36 BH_Eopnotsupp,
37 BH_Unwritten,
38 BH_Quiet,
39
40 BH_PrivateStart,
41
42
43};
44
45#define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512)
46
47struct page;
48struct buffer_head;
49struct address_space;
50typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
51
52
53
54
55
56
57
58
59
60
61struct buffer_head {
62 unsigned long b_state;
63 struct buffer_head *b_this_page;
64 struct page *b_page;
65
66 sector_t b_blocknr;
67 size_t b_size;
68 char *b_data;
69
70 struct block_device *b_bdev;
71 bh_end_io_t *b_end_io;
72 void *b_private;
73 struct list_head b_assoc_buffers;
74 struct address_space *b_assoc_map;
75
76 atomic_t b_count;
77};
78
79
80
81
82
83#define BUFFER_FNS(bit, name) \
84static inline void set_buffer_##name(struct buffer_head *bh) \
85{ \
86 set_bit(BH_##bit, &(bh)->b_state); \
87} \
88static inline void clear_buffer_##name(struct buffer_head *bh) \
89{ \
90 clear_bit(BH_##bit, &(bh)->b_state); \
91} \
92static inline int buffer_##name(const struct buffer_head *bh) \
93{ \
94 return test_bit(BH_##bit, &(bh)->b_state); \
95}
96
97
98
99
100#define TAS_BUFFER_FNS(bit, name) \
101static inline int test_set_buffer_##name(struct buffer_head *bh) \
102{ \
103 return test_and_set_bit(BH_##bit, &(bh)->b_state); \
104} \
105static 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
112
113
114
115BUFFER_FNS(Uptodate, uptodate)
116BUFFER_FNS(Dirty, dirty)
117TAS_BUFFER_FNS(Dirty, dirty)
118BUFFER_FNS(Lock, locked)
119BUFFER_FNS(Req, req)
120TAS_BUFFER_FNS(Req, req)
121BUFFER_FNS(Mapped, mapped)
122BUFFER_FNS(New, new)
123BUFFER_FNS(Async_Read, async_read)
124BUFFER_FNS(Async_Write, async_write)
125BUFFER_FNS(Delay, delay)
126BUFFER_FNS(Boundary, boundary)
127BUFFER_FNS(Write_EIO, write_io_error)
128BUFFER_FNS(Ordered, ordered)
129BUFFER_FNS(Eopnotsupp, eopnotsupp)
130BUFFER_FNS(Unwritten, unwritten)
131
132#define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK)
133#define touch_buffer(bh) mark_page_accessed(bh->b_page)
134
135
136#define page_buffers(page) \
137 ({ \
138 BUG_ON(!PagePrivate(page)); \
139 ((struct buffer_head *)page_private(page)); \
140 })
141#define page_has_buffers(page) PagePrivate(page)
142
143
144
145
146
147void mark_buffer_dirty(struct buffer_head *bh);
148void init_buffer(struct buffer_head *, bh_end_io_t *, void *);
149void set_bh_page(struct buffer_head *bh,
150 struct page *page, unsigned long offset);
151int try_to_free_buffers(struct page *);
152struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
153 int retry);
154void create_empty_buffers(struct page *, unsigned long,
155 unsigned long b_state);
156void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
157void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
158void end_buffer_async_write(struct buffer_head *bh, int uptodate);
159
160
161void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode);
162int inode_has_buffers(struct inode *);
163void invalidate_inode_buffers(struct inode *);
164int remove_inode_buffers(struct inode *inode);
165int sync_mapping_buffers(struct address_space *mapping);
166void unmap_underlying_metadata(struct block_device *bdev, sector_t block);
167
168void mark_buffer_async_write(struct buffer_head *bh);
169void __wait_on_buffer(struct buffer_head *);
170wait_queue_head_t *bh_waitq_head(struct buffer_head *bh);
171struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block,
172 unsigned size);
173struct buffer_head *__getblk(struct block_device *bdev, sector_t block,
174 unsigned size);
175void __brelse(struct buffer_head *);
176void __bforget(struct buffer_head *);
177void __breadahead(struct block_device *, sector_t block, unsigned int size);
178struct buffer_head *__bread(struct block_device *, sector_t block, unsigned size);
179void invalidate_bh_lrus(void);
180struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
181void free_buffer_head(struct buffer_head * bh);
182void unlock_buffer(struct buffer_head *bh);
183void __lock_buffer(struct buffer_head *bh);
184void ll_rw_block(int, int, struct buffer_head * bh[]);
185int sync_dirty_buffer(struct buffer_head *bh);
186int submit_bh(int, struct buffer_head *);
187void write_boundary_block(struct block_device *bdev,
188 sector_t bblock, unsigned blocksize);
189int bh_uptodate_or_lock(struct buffer_head *bh);
190int bh_submit_read(struct buffer_head *bh);
191
192extern int buffer_heads_over_limit;
193
194
195
196
197
198void block_invalidatepage(struct page *page, unsigned long offset);
199int block_write_full_page(struct page *page, get_block_t *get_block,
200 struct writeback_control *wbc);
201int block_write_full_page_endio(struct page *page, get_block_t *get_block,
202 struct writeback_control *wbc, bh_end_io_t *handler);
203int block_read_full_page(struct page*, get_block_t*);
204int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc,
205 unsigned long from);
206int block_write_begin(struct file *, struct address_space *,
207 loff_t, unsigned, unsigned,
208 struct page **, void **, get_block_t*);
209int block_write_end(struct file *, struct address_space *,
210 loff_t, unsigned, unsigned,
211 struct page *, void *);
212int generic_write_end(struct file *, struct address_space *,
213 loff_t, unsigned, unsigned,
214 struct page *, void *);
215void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
216int block_prepare_write(struct page*, unsigned, unsigned, get_block_t*);
217int cont_write_begin(struct file *, struct address_space *, loff_t,
218 unsigned, unsigned, struct page **, void **,
219 get_block_t *, loff_t *);
220int generic_cont_expand_simple(struct inode *inode, loff_t size);
221int block_commit_write(struct page *page, unsigned from, unsigned to);
222int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
223 get_block_t get_block);
224void block_sync_page(struct page *);
225sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *);
226int block_truncate_page(struct address_space *, loff_t, get_block_t *);
227int file_fsync(struct file *, struct dentry *, int);
228int nobh_write_begin(struct file *, struct address_space *,
229 loff_t, unsigned, unsigned,
230 struct page **, void **, get_block_t*);
231int nobh_write_end(struct file *, struct address_space *,
232 loff_t, unsigned, unsigned,
233 struct page *, void *);
234int nobh_truncate_page(struct address_space *, loff_t, get_block_t *);
235int nobh_writepage(struct page *page, get_block_t *get_block,
236 struct writeback_control *wbc);
237
238void buffer_init(void);
239
240
241
242
243
244static inline void attach_page_buffers(struct page *page,
245 struct buffer_head *head)
246{
247 page_cache_get(page);
248 SetPagePrivate(page);
249 set_page_private(page, (unsigned long)head);
250}
251
252static inline void get_bh(struct buffer_head *bh)
253{
254 atomic_inc(&bh->b_count);
255}
256
257static inline void put_bh(struct buffer_head *bh)
258{
259 smp_mb__before_atomic_dec();
260 atomic_dec(&bh->b_count);
261}
262
263static inline void brelse(struct buffer_head *bh)
264{
265 if (bh)
266 __brelse(bh);
267}
268
269static inline void bforget(struct buffer_head *bh)
270{
271 if (bh)
272 __bforget(bh);
273}
274
275static inline struct buffer_head *
276sb_bread(struct super_block *sb, sector_t block)
277{
278 return __bread(sb->s_bdev, block, sb->s_blocksize);
279}
280
281static inline void
282sb_breadahead(struct super_block *sb, sector_t block)
283{
284 __breadahead(sb->s_bdev, block, sb->s_blocksize);
285}
286
287static inline struct buffer_head *
288sb_getblk(struct super_block *sb, sector_t block)
289{
290 return __getblk(sb->s_bdev, block, sb->s_blocksize);
291}
292
293static inline struct buffer_head *
294sb_find_get_block(struct super_block *sb, sector_t block)
295{
296 return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
297}
298
299static inline void
300map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block)
301{
302 set_buffer_mapped(bh);
303 bh->b_bdev = sb->s_bdev;
304 bh->b_blocknr = block;
305 bh->b_size = sb->s_blocksize;
306}
307
308
309
310
311
312
313static inline void wait_on_buffer(struct buffer_head *bh)
314{
315 might_sleep();
316 if (buffer_locked(bh) || atomic_read(&bh->b_count) == 0)
317 __wait_on_buffer(bh);
318}
319
320static inline int trylock_buffer(struct buffer_head *bh)
321{
322 return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state));
323}
324
325static inline void lock_buffer(struct buffer_head *bh)
326{
327 might_sleep();
328 if (!trylock_buffer(bh))
329 __lock_buffer(bh);
330}
331
332extern int __set_page_dirty_buffers(struct page *page);
333
334#else
335
336static inline void buffer_init(void) {}
337static inline int try_to_free_buffers(struct page *page) { return 1; }
338static inline int inode_has_buffers(struct inode *inode) { return 0; }
339static inline void invalidate_inode_buffers(struct inode *inode) {}
340static inline int remove_inode_buffers(struct inode *inode) { return 1; }
341static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
342
343#endif
344#endif
345