diff options
Diffstat (limited to 'include/linux/buffer_head.h')
| -rw-r--r-- | include/linux/buffer_head.h | 296 |
1 files changed, 296 insertions, 0 deletions
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h new file mode 100644 index 00000000000..802c91e9b3d --- /dev/null +++ b/include/linux/buffer_head.h @@ -0,0 +1,296 @@ +/* + * include/linux/buffer_head.h + * + * Everything to do with buffer_heads. + */ + +#ifndef _LINUX_BUFFER_HEAD_H +#define _LINUX_BUFFER_HEAD_H + +#include <linux/types.h> +#include <linux/fs.h> +#include <linux/linkage.h> +#include <linux/pagemap.h> +#include <linux/wait.h> +#include <asm/atomic.h> + +enum bh_state_bits { + BH_Uptodate, /* Contains valid data */ + BH_Dirty, /* Is dirty */ + BH_Lock, /* Is locked */ + BH_Req, /* Has been submitted for I/O */ + + BH_Mapped, /* Has a disk mapping */ + BH_New, /* Disk mapping was newly created by get_block */ + BH_Async_Read, /* Is under end_buffer_async_read I/O */ + BH_Async_Write, /* Is under end_buffer_async_write I/O */ + BH_Delay, /* Buffer is not yet allocated on disk */ + BH_Boundary, /* Block is followed by a discontiguity */ + BH_Write_EIO, /* I/O error on write */ + BH_Ordered, /* ordered write */ + BH_Eopnotsupp, /* operation not supported (barrier) */ + + BH_PrivateStart,/* not a state bit, but the first bit available + * for private allocation by other entities + */ +}; + +#define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512) + +struct page; +struct buffer_head; +struct address_space; +typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate); + +/* + * Keep related fields in common cachelines. The most commonly accessed + * field (b_state) goes at the start so the compiler does not generate + * indexed addressing for it. + */ +struct buffer_head { + /* First cache line: */ + unsigned long b_state; /* buffer state bitmap (see above) */ + struct buffer_head *b_this_page;/* circular list of page's buffers */ + struct page *b_page; /* the page this bh is mapped to */ + atomic_t b_count; /* users using this block */ + u32 b_size; /* block size */ + + sector_t b_blocknr; /* block number */ + char *b_data; /* pointer to data block */ + + struct block_device *b_bdev; + bh_end_io_t *b_end_io; /* I/O completion */ + void *b_private; /* reserved for b_end_io */ + struct list_head b_assoc_buffers; /* associated with another mapping */ +}; + +/* + * macro tricks to expand the set_buffer_foo(), clear_buffer_foo() + * and buffer_foo() functions. + */ +#define BUFFER_FNS(bit, name) \ +static inline void set_buffer_##name(struct buffer_head *bh) \ +{ \ + set_bit(BH_##bit, &(bh)->b_state); \ +} \ +static inline void clear_buffer_##name(struct buffer_head *bh) \ +{ \ + clear_bit(BH_##bit, &(bh)->b_state); \ +} \ +static inline int buffer_##name(const struct buffer_head *bh) \ +{ \ + return test_bit(BH_##bit, &(bh)->b_state); \ +} + +/* + * test_set_buffer_foo() and test_clear_buffer_foo() + */ +#define TAS_BUFFER_FNS(bit, name) \ +static inline int test_set_buffer_##name(struct buffer_head *bh) \ +{ \ + return test_and_set_bit(BH_##bit, &(bh)->b_state); \ +} \ +static inline int test_clear_buffer_##name(struct buffer_head *bh) \ +{ \ + return test_and_clear_bit(BH_##bit, &(bh)->b_state); \ +} \ + +/* + * Emit the buffer bitops functions. Note that there are also functions + * of the form "mark_buffer_foo()". These are higher-level functions which + * do something in addition to setting a b_state bit. + */ +BUFFER_FNS(Uptodate, uptodate) +BUFFER_FNS(Dirty, dirty) +TAS_BUFFER_FNS(Dirty, dirty) +BUFFER_FNS(Lock, locked) +TAS_BUFFER_FNS(Lock, locked) +BUFFER_FNS(Req, req) +TAS_BUFFER_FNS(Req, req) +BUFFER_FNS(Mapped, mapped) +BUFFER_FNS(New, new) +BUFFER_FNS(Async_Read, async_read) +BUFFER_FNS(Async_Write, async_write) +BUFFER_FNS(Delay, delay) +BUFFER_FNS(Boundary, boundary) +BUFFER_FNS(Write_EIO, write_io_error) +BUFFER_FNS(Ordered, ordered) +BUFFER_FNS(Eopnotsupp, eopnotsupp) + +#define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK) +#define touch_buffer(bh) mark_page_accessed(bh->b_page) + +/* If we *know* page->private refers to buffer_heads */ +#define page_buffers(page) \ + ({ \ + BUG_ON(!PagePrivate(page)); \ + ((struct buffer_head *)(page)->private); \ + }) +#define page_has_buffers(page) PagePrivate(page) + +/* + * Declarations + */ + +void FASTCALL(mark_buffer_dirty(struct buffer_head *bh)); +void init_buffer(struct buffer_head *, bh_end_io_t *, void *); +void set_bh_page(struct buffer_head *bh, + struct page *page, unsigned long offset); +int try_to_free_buffers(struct page *); +struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, + int retry); +void create_empty_buffers(struct page *, unsigned long, + unsigned long b_state); +void end_buffer_read_sync(struct buffer_head *bh, int uptodate); +void end_buffer_write_sync(struct buffer_head *bh, int uptodate); +void end_buffer_async_write(struct buffer_head *bh, int uptodate); + +/* Things to do with buffers at mapping->private_list */ +void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode); +int inode_has_buffers(struct inode *); +void invalidate_inode_buffers(struct inode *); +int remove_inode_buffers(struct inode *inode); +int sync_mapping_buffers(struct address_space *mapping); +void unmap_underlying_metadata(struct block_device *bdev, sector_t block); + +void mark_buffer_async_write(struct buffer_head *bh); +void invalidate_bdev(struct block_device *, int); +int sync_blockdev(struct block_device *bdev); +void __wait_on_buffer(struct buffer_head *); +wait_queue_head_t *bh_waitq_head(struct buffer_head *bh); +int fsync_bdev(struct block_device *); +struct super_block *freeze_bdev(struct block_device *); +void thaw_bdev(struct block_device *, struct super_block *); +int fsync_super(struct super_block *); +int fsync_no_super(struct block_device *); +struct buffer_head *__find_get_block(struct block_device *, sector_t, int); +struct buffer_head * __getblk(struct block_device *, sector_t, int); +void __brelse(struct buffer_head *); +void __bforget(struct buffer_head *); +void __breadahead(struct block_device *, sector_t block, int size); +struct buffer_head *__bread(struct block_device *, sector_t block, int size); +struct buffer_head *alloc_buffer_head(unsigned int __nocast gfp_flags); +void free_buffer_head(struct buffer_head * bh); +void FASTCALL(unlock_buffer(struct buffer_head *bh)); +void FASTCALL(__lock_buffer(struct buffer_head *bh)); +void ll_rw_block(int, int, struct buffer_head * bh[]); +int sync_dirty_buffer(struct buffer_head *bh); +int submit_bh(int, struct buffer_head *); +void write_boundary_block(struct block_device *bdev, + sector_t bblock, unsigned blocksize); + +extern int buffer_heads_over_limit; + +/* + * Generic address_space_operations implementations for buffer_head-backed + * address_spaces. + */ +int try_to_release_page(struct page * page, int gfp_mask); +int block_invalidatepage(struct page *page, unsigned long offset); +int block_write_full_page(struct page *page, get_block_t *get_block, + struct writeback_control *wbc); +int block_read_full_page(struct page*, get_block_t*); +int block_prepare_write(struct page*, unsigned, unsigned, get_block_t*); +int cont_prepare_write(struct page*, unsigned, unsigned, get_block_t*, + loff_t *); +int generic_cont_expand(struct inode *inode, loff_t size) ; +int block_commit_write(struct page *page, unsigned from, unsigned to); +int block_sync_page(struct page *); +sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); +int generic_commit_write(struct file *, struct page *, unsigned, unsigned); +int block_truncate_page(struct address_space *, loff_t, get_block_t *); +int file_fsync(struct file *, struct dentry *, int); +int nobh_prepare_write(struct page*, unsigned, unsigned, get_block_t*); +int nobh_commit_write(struct file *, struct page *, unsigned, unsigned); +int nobh_truncate_page(struct address_space *, loff_t); +int nobh_writepage(struct page *page, get_block_t *get_block, + struct writeback_control *wbc); + + +/* + * inline definitions + */ + +static inline void attach_page_buffers(struct page *page, + struct buffer_head *head) +{ + page_cache_get(page); + SetPagePrivate(page); + page->private = (unsigned long)head; +} + +static inline void get_bh(struct buffer_head *bh) +{ + atomic_inc(&bh->b_count); +} + +static inline void put_bh(struct buffer_head *bh) +{ + smp_mb__before_atomic_dec(); + atomic_dec(&bh->b_count); +} + +static inline void brelse(struct buffer_head *bh) +{ + if (bh) + __brelse(bh); +} + +static inline void bforget(struct buffer_head *bh) +{ + if (bh) + __bforget(bh); +} + +static inline struct buffer_head * +sb_bread(struct super_block *sb, sector_t block) +{ + return __bread(sb->s_bdev, block, sb->s_blocksize); +} + +static inline void +sb_breadahead(struct super_block *sb, sector_t block) +{ + __breadahead(sb->s_bdev, block, sb->s_blocksize); +} + +static inline struct buffer_head * +sb_getblk(struct super_block *sb, sector_t block) +{ + return __getblk(sb->s_bdev, block, sb->s_blocksize); +} + +static inline struct buffer_head * +sb_find_get_block(struct super_block *sb, sector_t block) +{ + return __find_get_block(sb->s_bdev, block, sb->s_blocksize); +} + +static inline void +map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block) +{ + set_buffer_mapped(bh); + bh->b_bdev = sb->s_bdev; + bh->b_blocknr = block; +} + +/* + * Calling wait_on_buffer() for a zero-ref buffer is illegal, so we call into + * __wait_on_buffer() just to trip a debug check. Because debug code in inline + * functions is bloaty. + */ +static inline void wait_on_buffer(struct buffer_head *bh) +{ + might_sleep(); + if (buffer_locked(bh) || atomic_read(&bh->b_count) == 0) + __wait_on_buffer(bh); +} + +static inline void lock_buffer(struct buffer_head *bh) +{ + might_sleep(); + if (test_set_buffer_locked(bh)) + __lock_buffer(bh); +} + +#endif /* _LINUX_BUFFER_HEAD_H */ |