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1/* SPDX-License-Identifier: GPL-2.0 */
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>
16#include <linux/atomic.h>
17
18#ifdef CONFIG_BLOCK
19
20enum 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 */
33 BH_Unwritten, /* Buffer is allocated on disk but not written */
34 BH_Quiet, /* Buffer Error Prinks to be quiet */
35 BH_Meta, /* Buffer contains metadata */
36 BH_Prio, /* Buffer should be submitted with REQ_PRIO */
37 BH_Defer_Completion, /* Defer AIO completion to workqueue */
38
39 BH_PrivateStart,/* not a state bit, but the first bit available
40 * for private allocation by other entities
41 */
42};
43
44#define MAX_BUF_PER_PAGE (PAGE_SIZE / 512)
45
46struct page;
47struct buffer_head;
48struct address_space;
49typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
50
51/*
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).
59 */
60struct buffer_head {
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 */
64
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 */
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 */
73 struct address_space *b_assoc_map; /* mapping this buffer is
74 associated with */
75 atomic_t b_count; /* users using this buffer_head */
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 */
79};
80
81/*
82 * macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
83 * and buffer_foo() functions.
84 * To avoid reset buffer flags that are already set, because that causes
85 * a costly cache line transition, check the flag first.
86 */
87#define BUFFER_FNS(bit, name) \
88static __always_inline void set_buffer_##name(struct buffer_head *bh) \
89{ \
90 if (!test_bit(BH_##bit, &(bh)->b_state)) \
91 set_bit(BH_##bit, &(bh)->b_state); \
92} \
93static __always_inline void clear_buffer_##name(struct buffer_head *bh) \
94{ \
95 clear_bit(BH_##bit, &(bh)->b_state); \
96} \
97static __always_inline int buffer_##name(const struct buffer_head *bh) \
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) \
106static __always_inline int test_set_buffer_##name(struct buffer_head *bh) \
107{ \
108 return test_and_set_bit(BH_##bit, &(bh)->b_state); \
109} \
110static __always_inline int test_clear_buffer_##name(struct buffer_head *bh) \
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 */
120BUFFER_FNS(Uptodate, uptodate)
121BUFFER_FNS(Dirty, dirty)
122TAS_BUFFER_FNS(Dirty, dirty)
123BUFFER_FNS(Lock, locked)
124BUFFER_FNS(Req, req)
125TAS_BUFFER_FNS(Req, req)
126BUFFER_FNS(Mapped, mapped)
127BUFFER_FNS(New, new)
128BUFFER_FNS(Async_Read, async_read)
129BUFFER_FNS(Async_Write, async_write)
130BUFFER_FNS(Delay, delay)
131BUFFER_FNS(Boundary, boundary)
132BUFFER_FNS(Write_EIO, write_io_error)
133BUFFER_FNS(Unwritten, unwritten)
134BUFFER_FNS(Meta, meta)
135BUFFER_FNS(Prio, prio)
136BUFFER_FNS(Defer_Completion, defer_completion)
137
138#define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK)
139
140/* If we *know* page->private refers to buffer_heads */
141#define page_buffers(page) \
142 ({ \
143 BUG_ON(!PagePrivate(page)); \
144 ((struct buffer_head *)page_private(page)); \
145 })
146#define page_has_buffers(page) PagePrivate(page)
147
148void buffer_check_dirty_writeback(struct page *page,
149 bool *dirty, bool *writeback);
150
151/*
152 * Declarations
153 */
154
155void mark_buffer_dirty(struct buffer_head *bh);
156void mark_buffer_write_io_error(struct buffer_head *bh);
157void touch_buffer(struct buffer_head *bh);
158void set_bh_page(struct buffer_head *bh,
159 struct page *page, unsigned long offset);
160int try_to_free_buffers(struct page *);
161struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
162 bool retry);
163void create_empty_buffers(struct page *, unsigned long,
164 unsigned long b_state);
165void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
166void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
167void end_buffer_async_write(struct buffer_head *bh, int uptodate);
168
169/* Things to do with buffers at mapping->private_list */
170void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode);
171int inode_has_buffers(struct inode *);
172void invalidate_inode_buffers(struct inode *);
173int remove_inode_buffers(struct inode *inode);
174int sync_mapping_buffers(struct address_space *mapping);
175void clean_bdev_aliases(struct block_device *bdev, sector_t block,
176 sector_t len);
177static inline void clean_bdev_bh_alias(struct buffer_head *bh)
178{
179 clean_bdev_aliases(bh->b_bdev, bh->b_blocknr, 1);
180}
181
182void mark_buffer_async_write(struct buffer_head *bh);
183void __wait_on_buffer(struct buffer_head *);
184wait_queue_head_t *bh_waitq_head(struct buffer_head *bh);
185struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block,
186 unsigned size);
187struct buffer_head *__getblk_gfp(struct block_device *bdev, sector_t block,
188 unsigned size, gfp_t gfp);
189void __brelse(struct buffer_head *);
190void __bforget(struct buffer_head *);
191void __breadahead(struct block_device *, sector_t block, unsigned int size);
192void __breadahead_gfp(struct block_device *, sector_t block, unsigned int size,
193 gfp_t gfp);
194struct buffer_head *__bread_gfp(struct block_device *,
195 sector_t block, unsigned size, gfp_t gfp);
196void invalidate_bh_lrus(void);
197struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
198void free_buffer_head(struct buffer_head * bh);
199void unlock_buffer(struct buffer_head *bh);
200void __lock_buffer(struct buffer_head *bh);
201void ll_rw_block(int, int, int, struct buffer_head * bh[]);
202int sync_dirty_buffer(struct buffer_head *bh);
203int __sync_dirty_buffer(struct buffer_head *bh, int op_flags);
204void write_dirty_buffer(struct buffer_head *bh, int op_flags);
205int submit_bh(int, int, struct buffer_head *);
206void write_boundary_block(struct block_device *bdev,
207 sector_t bblock, unsigned blocksize);
208int bh_uptodate_or_lock(struct buffer_head *bh);
209int bh_submit_read(struct buffer_head *bh);
210
211extern int buffer_heads_over_limit;
212
213/*
214 * Generic address_space_operations implementations for buffer_head-backed
215 * address_spaces.
216 */
217void block_invalidatepage(struct page *page, unsigned int offset,
218 unsigned int length);
219int block_write_full_page(struct page *page, get_block_t *get_block,
220 struct writeback_control *wbc);
221int __block_write_full_page(struct inode *inode, struct page *page,
222 get_block_t *get_block, struct writeback_control *wbc,
223 bh_end_io_t *handler);
224int block_read_full_page(struct page*, get_block_t*);
225int block_is_partially_uptodate(struct page *page, unsigned long from,
226 unsigned long count);
227int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len,
228 unsigned flags, struct page **pagep, get_block_t *get_block);
229int __block_write_begin(struct page *page, loff_t pos, unsigned len,
230 get_block_t *get_block);
231int block_write_end(struct file *, struct address_space *,
232 loff_t, unsigned, unsigned,
233 struct page *, void *);
234int generic_write_end(struct file *, struct address_space *,
235 loff_t, unsigned, unsigned,
236 struct page *, void *);
237void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
238void clean_page_buffers(struct page *page);
239int cont_write_begin(struct file *, struct address_space *, loff_t,
240 unsigned, unsigned, struct page **, void **,
241 get_block_t *, loff_t *);
242int generic_cont_expand_simple(struct inode *inode, loff_t size);
243int block_commit_write(struct page *page, unsigned from, unsigned to);
244int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
245 get_block_t get_block);
246/* Convert errno to return value from ->page_mkwrite() call */
247static inline vm_fault_t block_page_mkwrite_return(int err)
248{
249 if (err == 0)
250 return VM_FAULT_LOCKED;
251 if (err == -EFAULT || err == -EAGAIN)
252 return VM_FAULT_NOPAGE;
253 if (err == -ENOMEM)
254 return VM_FAULT_OOM;
255 /* -ENOSPC, -EDQUOT, -EIO ... */
256 return VM_FAULT_SIGBUS;
257}
258sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *);
259int block_truncate_page(struct address_space *, loff_t, get_block_t *);
260int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned,
261 struct page **, void **, get_block_t*);
262int nobh_write_end(struct file *, struct address_space *,
263 loff_t, unsigned, unsigned,
264 struct page *, void *);
265int nobh_truncate_page(struct address_space *, loff_t, get_block_t *);
266int nobh_writepage(struct page *page, get_block_t *get_block,
267 struct writeback_control *wbc);
268
269void buffer_init(void);
270
271/*
272 * inline definitions
273 */
274
275static inline void get_bh(struct buffer_head *bh)
276{
277 atomic_inc(&bh->b_count);
278}
279
280static inline void put_bh(struct buffer_head *bh)
281{
282 smp_mb__before_atomic();
283 atomic_dec(&bh->b_count);
284}
285
286static inline void brelse(struct buffer_head *bh)
287{
288 if (bh)
289 __brelse(bh);
290}
291
292static inline void bforget(struct buffer_head *bh)
293{
294 if (bh)
295 __bforget(bh);
296}
297
298static inline struct buffer_head *
299sb_bread(struct super_block *sb, sector_t block)
300{
301 return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
302}
303
304static inline struct buffer_head *
305sb_bread_unmovable(struct super_block *sb, sector_t block)
306{
307 return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, 0);
308}
309
310static inline void
311sb_breadahead(struct super_block *sb, sector_t block)
312{
313 __breadahead(sb->s_bdev, block, sb->s_blocksize);
314}
315
316static inline void
317sb_breadahead_unmovable(struct super_block *sb, sector_t block)
318{
319 __breadahead_gfp(sb->s_bdev, block, sb->s_blocksize, 0);
320}
321
322static inline struct buffer_head *
323sb_getblk(struct super_block *sb, sector_t block)
324{
325 return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
326}
327
328
329static inline struct buffer_head *
330sb_getblk_gfp(struct super_block *sb, sector_t block, gfp_t gfp)
331{
332 return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, gfp);
333}
334
335static inline struct buffer_head *
336sb_find_get_block(struct super_block *sb, sector_t block)
337{
338 return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
339}
340
341static inline void
342map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block)
343{
344 set_buffer_mapped(bh);
345 bh->b_bdev = sb->s_bdev;
346 bh->b_blocknr = block;
347 bh->b_size = sb->s_blocksize;
348}
349
350static inline void wait_on_buffer(struct buffer_head *bh)
351{
352 might_sleep();
353 if (buffer_locked(bh))
354 __wait_on_buffer(bh);
355}
356
357static inline int trylock_buffer(struct buffer_head *bh)
358{
359 return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state));
360}
361
362static inline void lock_buffer(struct buffer_head *bh)
363{
364 might_sleep();
365 if (!trylock_buffer(bh))
366 __lock_buffer(bh);
367}
368
369static inline struct buffer_head *getblk_unmovable(struct block_device *bdev,
370 sector_t block,
371 unsigned size)
372{
373 return __getblk_gfp(bdev, block, size, 0);
374}
375
376static inline struct buffer_head *__getblk(struct block_device *bdev,
377 sector_t block,
378 unsigned size)
379{
380 return __getblk_gfp(bdev, block, size, __GFP_MOVABLE);
381}
382
383/**
384 * __bread() - reads a specified block and returns the bh
385 * @bdev: the block_device to read from
386 * @block: number of block
387 * @size: size (in bytes) to read
388 *
389 * Reads a specified block, and returns buffer head that contains it.
390 * The page cache is allocated from movable area so that it can be migrated.
391 * It returns NULL if the block was unreadable.
392 */
393static inline struct buffer_head *
394__bread(struct block_device *bdev, sector_t block, unsigned size)
395{
396 return __bread_gfp(bdev, block, size, __GFP_MOVABLE);
397}
398
399extern int __set_page_dirty_buffers(struct page *page);
400
401#else /* CONFIG_BLOCK */
402
403static inline void buffer_init(void) {}
404static inline int try_to_free_buffers(struct page *page) { return 1; }
405static inline int inode_has_buffers(struct inode *inode) { return 0; }
406static inline void invalidate_inode_buffers(struct inode *inode) {}
407static inline int remove_inode_buffers(struct inode *inode) { return 1; }
408static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
409#define buffer_heads_over_limit 0
410
411#endif /* CONFIG_BLOCK */
412#endif /* _LINUX_BUFFER_HEAD_H */
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 <linux/atomic.h>
16
17#ifdef CONFIG_BLOCK
18
19enum 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 */
24 BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise
25 * IO completion of other buffers in the page
26 */
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 */
35 BH_Unwritten, /* Buffer is allocated on disk but not written */
36 BH_Quiet, /* Buffer Error Prinks to be quiet */
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
45struct page;
46struct buffer_head;
47struct address_space;
48typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
49
50/*
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).
58 */
59struct buffer_head {
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 */
63
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 */
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 */
72 struct address_space *b_assoc_map; /* mapping this buffer is
73 associated with */
74 atomic_t b_count; /* users using this buffer_head */
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) \
82static inline void set_buffer_##name(struct buffer_head *bh) \
83{ \
84 set_bit(BH_##bit, &(bh)->b_state); \
85} \
86static inline void clear_buffer_##name(struct buffer_head *bh) \
87{ \
88 clear_bit(BH_##bit, &(bh)->b_state); \
89} \
90static 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) \
99static inline int test_set_buffer_##name(struct buffer_head *bh) \
100{ \
101 return test_and_set_bit(BH_##bit, &(bh)->b_state); \
102} \
103static 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 */
113BUFFER_FNS(Uptodate, uptodate)
114BUFFER_FNS(Dirty, dirty)
115TAS_BUFFER_FNS(Dirty, dirty)
116BUFFER_FNS(Lock, locked)
117BUFFER_FNS(Req, req)
118TAS_BUFFER_FNS(Req, req)
119BUFFER_FNS(Mapped, mapped)
120BUFFER_FNS(New, new)
121BUFFER_FNS(Async_Read, async_read)
122BUFFER_FNS(Async_Write, async_write)
123BUFFER_FNS(Delay, delay)
124BUFFER_FNS(Boundary, boundary)
125BUFFER_FNS(Write_EIO, write_io_error)
126BUFFER_FNS(Unwritten, unwritten)
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 ({ \
134 BUG_ON(!PagePrivate(page)); \
135 ((struct buffer_head *)page_private(page)); \
136 })
137#define page_has_buffers(page) PagePrivate(page)
138
139/*
140 * Declarations
141 */
142
143void mark_buffer_dirty(struct buffer_head *bh);
144void init_buffer(struct buffer_head *, bh_end_io_t *, void *);
145void set_bh_page(struct buffer_head *bh,
146 struct page *page, unsigned long offset);
147int try_to_free_buffers(struct page *);
148struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
149 int retry);
150void create_empty_buffers(struct page *, unsigned long,
151 unsigned long b_state);
152void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
153void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
154void end_buffer_async_write(struct buffer_head *bh, int uptodate);
155
156/* Things to do with buffers at mapping->private_list */
157void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode);
158int inode_has_buffers(struct inode *);
159void invalidate_inode_buffers(struct inode *);
160int remove_inode_buffers(struct inode *inode);
161int sync_mapping_buffers(struct address_space *mapping);
162void unmap_underlying_metadata(struct block_device *bdev, sector_t block);
163
164void mark_buffer_async_write(struct buffer_head *bh);
165void __wait_on_buffer(struct buffer_head *);
166wait_queue_head_t *bh_waitq_head(struct buffer_head *bh);
167struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block,
168 unsigned size);
169struct buffer_head *__getblk(struct block_device *bdev, sector_t block,
170 unsigned size);
171void __brelse(struct buffer_head *);
172void __bforget(struct buffer_head *);
173void __breadahead(struct block_device *, sector_t block, unsigned int size);
174struct buffer_head *__bread(struct block_device *, sector_t block, unsigned size);
175void invalidate_bh_lrus(void);
176struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
177void free_buffer_head(struct buffer_head * bh);
178void unlock_buffer(struct buffer_head *bh);
179void __lock_buffer(struct buffer_head *bh);
180void ll_rw_block(int, int, struct buffer_head * bh[]);
181int sync_dirty_buffer(struct buffer_head *bh);
182int __sync_dirty_buffer(struct buffer_head *bh, int rw);
183void write_dirty_buffer(struct buffer_head *bh, int rw);
184int submit_bh(int, struct buffer_head *);
185void write_boundary_block(struct block_device *bdev,
186 sector_t bblock, unsigned blocksize);
187int bh_uptodate_or_lock(struct buffer_head *bh);
188int bh_submit_read(struct buffer_head *bh);
189
190extern int buffer_heads_over_limit;
191
192/*
193 * Generic address_space_operations implementations for buffer_head-backed
194 * address_spaces.
195 */
196void block_invalidatepage(struct page *page, unsigned long offset);
197int block_write_full_page(struct page *page, get_block_t *get_block,
198 struct writeback_control *wbc);
199int block_write_full_page_endio(struct page *page, get_block_t *get_block,
200 struct writeback_control *wbc, bh_end_io_t *handler);
201int block_read_full_page(struct page*, get_block_t*);
202int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc,
203 unsigned long from);
204int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len,
205 unsigned flags, struct page **pagep, get_block_t *get_block);
206int __block_write_begin(struct page *page, loff_t pos, unsigned len,
207 get_block_t *get_block);
208int block_write_end(struct file *, struct address_space *,
209 loff_t, unsigned, unsigned,
210 struct page *, void *);
211int generic_write_end(struct file *, struct address_space *,
212 loff_t, unsigned, unsigned,
213 struct page *, void *);
214void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
215int cont_write_begin(struct file *, struct address_space *, loff_t,
216 unsigned, unsigned, struct page **, void **,
217 get_block_t *, loff_t *);
218int generic_cont_expand_simple(struct inode *inode, loff_t size);
219int block_commit_write(struct page *page, unsigned from, unsigned to);
220int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
221 get_block_t get_block);
222int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
223 get_block_t get_block);
224/* Convert errno to return value from ->page_mkwrite() call */
225static inline int block_page_mkwrite_return(int err)
226{
227 if (err == 0)
228 return VM_FAULT_LOCKED;
229 if (err == -EFAULT)
230 return VM_FAULT_NOPAGE;
231 if (err == -ENOMEM)
232 return VM_FAULT_OOM;
233 if (err == -EAGAIN)
234 return VM_FAULT_RETRY;
235 /* -ENOSPC, -EDQUOT, -EIO ... */
236 return VM_FAULT_SIGBUS;
237}
238sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *);
239int block_truncate_page(struct address_space *, loff_t, get_block_t *);
240int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned,
241 struct page **, void **, get_block_t*);
242int nobh_write_end(struct file *, struct address_space *,
243 loff_t, unsigned, unsigned,
244 struct page *, void *);
245int nobh_truncate_page(struct address_space *, loff_t, get_block_t *);
246int nobh_writepage(struct page *page, get_block_t *get_block,
247 struct writeback_control *wbc);
248
249void buffer_init(void);
250
251/*
252 * inline definitions
253 */
254
255static inline void attach_page_buffers(struct page *page,
256 struct buffer_head *head)
257{
258 page_cache_get(page);
259 SetPagePrivate(page);
260 set_page_private(page, (unsigned long)head);
261}
262
263static inline void get_bh(struct buffer_head *bh)
264{
265 atomic_inc(&bh->b_count);
266}
267
268static inline void put_bh(struct buffer_head *bh)
269{
270 smp_mb__before_atomic_dec();
271 atomic_dec(&bh->b_count);
272}
273
274static inline void brelse(struct buffer_head *bh)
275{
276 if (bh)
277 __brelse(bh);
278}
279
280static inline void bforget(struct buffer_head *bh)
281{
282 if (bh)
283 __bforget(bh);
284}
285
286static inline struct buffer_head *
287sb_bread(struct super_block *sb, sector_t block)
288{
289 return __bread(sb->s_bdev, block, sb->s_blocksize);
290}
291
292static inline void
293sb_breadahead(struct super_block *sb, sector_t block)
294{
295 __breadahead(sb->s_bdev, block, sb->s_blocksize);
296}
297
298static inline struct buffer_head *
299sb_getblk(struct super_block *sb, sector_t block)
300{
301 return __getblk(sb->s_bdev, block, sb->s_blocksize);
302}
303
304static inline struct buffer_head *
305sb_find_get_block(struct super_block *sb, sector_t block)
306{
307 return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
308}
309
310static inline void
311map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block)
312{
313 set_buffer_mapped(bh);
314 bh->b_bdev = sb->s_bdev;
315 bh->b_blocknr = block;
316 bh->b_size = sb->s_blocksize;
317}
318
319static inline void wait_on_buffer(struct buffer_head *bh)
320{
321 might_sleep();
322 if (buffer_locked(bh))
323 __wait_on_buffer(bh);
324}
325
326static inline int trylock_buffer(struct buffer_head *bh)
327{
328 return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state));
329}
330
331static inline void lock_buffer(struct buffer_head *bh)
332{
333 might_sleep();
334 if (!trylock_buffer(bh))
335 __lock_buffer(bh);
336}
337
338extern int __set_page_dirty_buffers(struct page *page);
339
340#else /* CONFIG_BLOCK */
341
342static inline void buffer_init(void) {}
343static inline int try_to_free_buffers(struct page *page) { return 1; }
344static inline int inode_has_buffers(struct inode *inode) { return 0; }
345static inline void invalidate_inode_buffers(struct inode *inode) {}
346static inline int remove_inode_buffers(struct inode *inode) { return 1; }
347static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
348
349#endif /* CONFIG_BLOCK */
350#endif /* _LINUX_BUFFER_HEAD_H */