BH_Dirty, /* Is dirty */
BH_Lock, /* Is locked */
BH_Req, /* Has been submitted for I/O */
+ BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise
+ * IO completion of other buffers in the page
+ */
BH_Mapped, /* Has a disk mapping */
BH_New, /* Disk mapping was newly created by get_block */
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.
+ * Historically, a buffer_head was used to map a single block
+ * within a page, and of course as the unit of I/O through the
+ * filesystem and block layers. Nowadays the basic I/O unit
+ * is the bio, and buffer_heads are used for extracting block
+ * mappings (via a get_block_t call), for tracking state within
+ * a page (via a page_mapping) and for wrapping bio submission
+ * for backward compatibility reasons (e.g. submit_bh).
*/
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 */
+ sector_t b_blocknr; /* start block number */
+ size_t b_size; /* size of mapping */
+ char *b_data; /* pointer to data within the page */
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 */
+ atomic_t b_count; /* users using this buffer_head */
};
/*
/* If we *know* page->private refers to buffer_heads */
#define page_buffers(page) \
({ \
- BUG_ON(!PagePrivate(page)); \
- ((struct buffer_head *)(page)->private); \
+ BUG_ON(!PagePrivate(page)); \
+ ((struct buffer_head *)page_private(page)); \
})
#define page_has_buffers(page) PagePrivate(page)
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);
+struct buffer_head *alloc_buffer_head(gfp_t 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));
* 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 try_to_release_page(struct page * page, gfp_t gfp_mask);
+void block_invalidatepage(struct page *page, unsigned long offset);
+void do_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 generic_cont_expand(struct inode *inode, loff_t size);
+int generic_cont_expand_simple(struct inode *inode, loff_t size);
int block_commit_write(struct page *page, unsigned from, unsigned to);
-int block_sync_page(struct page *);
+void block_sync_page(struct page *);
void flush_inode_pages (struct inode * inode);
sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *);
int generic_commit_write(struct file *, struct page *, unsigned, unsigned);
{
page_cache_get(page);
SetPagePrivate(page);
- page->private = (unsigned long)head;
+ set_page_private(page, (unsigned long)head);
}
static inline void get_bh(struct buffer_head *bh)
set_buffer_mapped(bh);
bh->b_bdev = sb->s_bdev;
bh->b_blocknr = block;
+ bh->b_size = sb->s_blocksize;
}
/*