Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
| 17 | enum bh_state_bits { |
| 18 | BH_Uptodate, /* Contains valid data */ |
| 19 | BH_Dirty, /* Is dirty */ |
| 20 | BH_Lock, /* Is locked */ |
| 21 | BH_Req, /* Has been submitted for I/O */ |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 22 | BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise |
| 23 | * IO completion of other buffers in the page |
| 24 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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_Ordered, /* ordered write */ |
| 34 | BH_Eopnotsupp, /* operation not supported (barrier) */ |
| 35 | |
| 36 | BH_PrivateStart,/* not a state bit, but the first bit available |
| 37 | * for private allocation by other entities |
| 38 | */ |
| 39 | }; |
| 40 | |
| 41 | #define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512) |
| 42 | |
| 43 | struct page; |
| 44 | struct buffer_head; |
| 45 | struct address_space; |
| 46 | typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate); |
| 47 | |
| 48 | /* |
| 49 | * Keep related fields in common cachelines. The most commonly accessed |
| 50 | * field (b_state) goes at the start so the compiler does not generate |
| 51 | * indexed addressing for it. |
| 52 | */ |
| 53 | struct buffer_head { |
| 54 | /* First cache line: */ |
| 55 | unsigned long b_state; /* buffer state bitmap (see above) */ |
| 56 | struct buffer_head *b_this_page;/* circular list of page's buffers */ |
| 57 | struct page *b_page; /* the page this bh is mapped to */ |
| 58 | atomic_t b_count; /* users using this block */ |
| 59 | u32 b_size; /* block size */ |
| 60 | |
| 61 | sector_t b_blocknr; /* block number */ |
| 62 | char *b_data; /* pointer to data block */ |
| 63 | |
| 64 | struct block_device *b_bdev; |
| 65 | bh_end_io_t *b_end_io; /* I/O completion */ |
| 66 | void *b_private; /* reserved for b_end_io */ |
| 67 | struct list_head b_assoc_buffers; /* associated with another mapping */ |
| 68 | }; |
| 69 | |
| 70 | /* |
| 71 | * macro tricks to expand the set_buffer_foo(), clear_buffer_foo() |
| 72 | * and buffer_foo() functions. |
| 73 | */ |
| 74 | #define BUFFER_FNS(bit, name) \ |
| 75 | static inline void set_buffer_##name(struct buffer_head *bh) \ |
| 76 | { \ |
| 77 | set_bit(BH_##bit, &(bh)->b_state); \ |
| 78 | } \ |
| 79 | static inline void clear_buffer_##name(struct buffer_head *bh) \ |
| 80 | { \ |
| 81 | clear_bit(BH_##bit, &(bh)->b_state); \ |
| 82 | } \ |
| 83 | static inline int buffer_##name(const struct buffer_head *bh) \ |
| 84 | { \ |
| 85 | return test_bit(BH_##bit, &(bh)->b_state); \ |
| 86 | } |
| 87 | |
| 88 | /* |
| 89 | * test_set_buffer_foo() and test_clear_buffer_foo() |
| 90 | */ |
| 91 | #define TAS_BUFFER_FNS(bit, name) \ |
| 92 | static inline int test_set_buffer_##name(struct buffer_head *bh) \ |
| 93 | { \ |
| 94 | return test_and_set_bit(BH_##bit, &(bh)->b_state); \ |
| 95 | } \ |
| 96 | static inline int test_clear_buffer_##name(struct buffer_head *bh) \ |
| 97 | { \ |
| 98 | return test_and_clear_bit(BH_##bit, &(bh)->b_state); \ |
| 99 | } \ |
| 100 | |
| 101 | /* |
| 102 | * Emit the buffer bitops functions. Note that there are also functions |
| 103 | * of the form "mark_buffer_foo()". These are higher-level functions which |
| 104 | * do something in addition to setting a b_state bit. |
| 105 | */ |
| 106 | BUFFER_FNS(Uptodate, uptodate) |
| 107 | BUFFER_FNS(Dirty, dirty) |
| 108 | TAS_BUFFER_FNS(Dirty, dirty) |
| 109 | BUFFER_FNS(Lock, locked) |
| 110 | TAS_BUFFER_FNS(Lock, locked) |
| 111 | BUFFER_FNS(Req, req) |
| 112 | TAS_BUFFER_FNS(Req, req) |
| 113 | BUFFER_FNS(Mapped, mapped) |
| 114 | BUFFER_FNS(New, new) |
| 115 | BUFFER_FNS(Async_Read, async_read) |
| 116 | BUFFER_FNS(Async_Write, async_write) |
| 117 | BUFFER_FNS(Delay, delay) |
| 118 | BUFFER_FNS(Boundary, boundary) |
| 119 | BUFFER_FNS(Write_EIO, write_io_error) |
| 120 | BUFFER_FNS(Ordered, ordered) |
| 121 | BUFFER_FNS(Eopnotsupp, eopnotsupp) |
| 122 | |
| 123 | #define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK) |
| 124 | #define touch_buffer(bh) mark_page_accessed(bh->b_page) |
| 125 | |
| 126 | /* If we *know* page->private refers to buffer_heads */ |
| 127 | #define page_buffers(page) \ |
| 128 | ({ \ |
| 129 | BUG_ON(!PagePrivate(page)); \ |
| 130 | ((struct buffer_head *)(page)->private); \ |
| 131 | }) |
| 132 | #define page_has_buffers(page) PagePrivate(page) |
| 133 | |
| 134 | /* |
| 135 | * Declarations |
| 136 | */ |
| 137 | |
| 138 | void FASTCALL(mark_buffer_dirty(struct buffer_head *bh)); |
| 139 | void init_buffer(struct buffer_head *, bh_end_io_t *, void *); |
| 140 | void set_bh_page(struct buffer_head *bh, |
| 141 | struct page *page, unsigned long offset); |
| 142 | int try_to_free_buffers(struct page *); |
| 143 | struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, |
| 144 | int retry); |
| 145 | void create_empty_buffers(struct page *, unsigned long, |
| 146 | unsigned long b_state); |
| 147 | void end_buffer_read_sync(struct buffer_head *bh, int uptodate); |
| 148 | void end_buffer_write_sync(struct buffer_head *bh, int uptodate); |
| 149 | void end_buffer_async_write(struct buffer_head *bh, int uptodate); |
| 150 | |
| 151 | /* Things to do with buffers at mapping->private_list */ |
| 152 | void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode); |
| 153 | int inode_has_buffers(struct inode *); |
| 154 | void invalidate_inode_buffers(struct inode *); |
| 155 | int remove_inode_buffers(struct inode *inode); |
| 156 | int sync_mapping_buffers(struct address_space *mapping); |
| 157 | void unmap_underlying_metadata(struct block_device *bdev, sector_t block); |
| 158 | |
| 159 | void mark_buffer_async_write(struct buffer_head *bh); |
| 160 | void invalidate_bdev(struct block_device *, int); |
| 161 | int sync_blockdev(struct block_device *bdev); |
| 162 | void __wait_on_buffer(struct buffer_head *); |
| 163 | wait_queue_head_t *bh_waitq_head(struct buffer_head *bh); |
| 164 | int fsync_bdev(struct block_device *); |
| 165 | struct super_block *freeze_bdev(struct block_device *); |
| 166 | void thaw_bdev(struct block_device *, struct super_block *); |
| 167 | int fsync_super(struct super_block *); |
| 168 | int fsync_no_super(struct block_device *); |
| 169 | struct buffer_head *__find_get_block(struct block_device *, sector_t, int); |
| 170 | struct buffer_head * __getblk(struct block_device *, sector_t, int); |
| 171 | void __brelse(struct buffer_head *); |
| 172 | void __bforget(struct buffer_head *); |
| 173 | void __breadahead(struct block_device *, sector_t block, int size); |
| 174 | struct buffer_head *__bread(struct block_device *, sector_t block, int size); |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 175 | struct buffer_head *alloc_buffer_head(gfp_t gfp_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | void free_buffer_head(struct buffer_head * bh); |
| 177 | void FASTCALL(unlock_buffer(struct buffer_head *bh)); |
| 178 | void FASTCALL(__lock_buffer(struct buffer_head *bh)); |
| 179 | void ll_rw_block(int, int, struct buffer_head * bh[]); |
| 180 | int sync_dirty_buffer(struct buffer_head *bh); |
| 181 | int submit_bh(int, struct buffer_head *); |
| 182 | void write_boundary_block(struct block_device *bdev, |
| 183 | sector_t bblock, unsigned blocksize); |
| 184 | |
| 185 | extern int buffer_heads_over_limit; |
| 186 | |
| 187 | /* |
| 188 | * Generic address_space_operations implementations for buffer_head-backed |
| 189 | * address_spaces. |
| 190 | */ |
Al Viro | 27496a8 | 2005-10-21 03:20:48 -0400 | [diff] [blame] | 191 | int try_to_release_page(struct page * page, gfp_t gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | int block_invalidatepage(struct page *page, unsigned long offset); |
| 193 | int block_write_full_page(struct page *page, get_block_t *get_block, |
| 194 | struct writeback_control *wbc); |
| 195 | int block_read_full_page(struct page*, get_block_t*); |
| 196 | int block_prepare_write(struct page*, unsigned, unsigned, get_block_t*); |
| 197 | int cont_prepare_write(struct page*, unsigned, unsigned, get_block_t*, |
| 198 | loff_t *); |
| 199 | int generic_cont_expand(struct inode *inode, loff_t size) ; |
| 200 | int block_commit_write(struct page *page, unsigned from, unsigned to); |
| 201 | int block_sync_page(struct page *); |
| 202 | sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); |
| 203 | int generic_commit_write(struct file *, struct page *, unsigned, unsigned); |
| 204 | int block_truncate_page(struct address_space *, loff_t, get_block_t *); |
| 205 | int file_fsync(struct file *, struct dentry *, int); |
| 206 | int nobh_prepare_write(struct page*, unsigned, unsigned, get_block_t*); |
| 207 | int nobh_commit_write(struct file *, struct page *, unsigned, unsigned); |
| 208 | int nobh_truncate_page(struct address_space *, loff_t); |
| 209 | int nobh_writepage(struct page *page, get_block_t *get_block, |
| 210 | struct writeback_control *wbc); |
| 211 | |
| 212 | |
| 213 | /* |
| 214 | * inline definitions |
| 215 | */ |
| 216 | |
| 217 | static inline void attach_page_buffers(struct page *page, |
| 218 | struct buffer_head *head) |
| 219 | { |
| 220 | page_cache_get(page); |
| 221 | SetPagePrivate(page); |
| 222 | page->private = (unsigned long)head; |
| 223 | } |
| 224 | |
| 225 | static inline void get_bh(struct buffer_head *bh) |
| 226 | { |
| 227 | atomic_inc(&bh->b_count); |
| 228 | } |
| 229 | |
| 230 | static inline void put_bh(struct buffer_head *bh) |
| 231 | { |
| 232 | smp_mb__before_atomic_dec(); |
| 233 | atomic_dec(&bh->b_count); |
| 234 | } |
| 235 | |
| 236 | static inline void brelse(struct buffer_head *bh) |
| 237 | { |
| 238 | if (bh) |
| 239 | __brelse(bh); |
| 240 | } |
| 241 | |
| 242 | static inline void bforget(struct buffer_head *bh) |
| 243 | { |
| 244 | if (bh) |
| 245 | __bforget(bh); |
| 246 | } |
| 247 | |
| 248 | static inline struct buffer_head * |
| 249 | sb_bread(struct super_block *sb, sector_t block) |
| 250 | { |
| 251 | return __bread(sb->s_bdev, block, sb->s_blocksize); |
| 252 | } |
| 253 | |
| 254 | static inline void |
| 255 | sb_breadahead(struct super_block *sb, sector_t block) |
| 256 | { |
| 257 | __breadahead(sb->s_bdev, block, sb->s_blocksize); |
| 258 | } |
| 259 | |
| 260 | static inline struct buffer_head * |
| 261 | sb_getblk(struct super_block *sb, sector_t block) |
| 262 | { |
| 263 | return __getblk(sb->s_bdev, block, sb->s_blocksize); |
| 264 | } |
| 265 | |
| 266 | static inline struct buffer_head * |
| 267 | sb_find_get_block(struct super_block *sb, sector_t block) |
| 268 | { |
| 269 | return __find_get_block(sb->s_bdev, block, sb->s_blocksize); |
| 270 | } |
| 271 | |
| 272 | static inline void |
| 273 | map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block) |
| 274 | { |
| 275 | set_buffer_mapped(bh); |
| 276 | bh->b_bdev = sb->s_bdev; |
| 277 | bh->b_blocknr = block; |
| 278 | } |
| 279 | |
| 280 | /* |
| 281 | * Calling wait_on_buffer() for a zero-ref buffer is illegal, so we call into |
| 282 | * __wait_on_buffer() just to trip a debug check. Because debug code in inline |
| 283 | * functions is bloaty. |
| 284 | */ |
| 285 | static inline void wait_on_buffer(struct buffer_head *bh) |
| 286 | { |
| 287 | might_sleep(); |
| 288 | if (buffer_locked(bh) || atomic_read(&bh->b_count) == 0) |
| 289 | __wait_on_buffer(bh); |
| 290 | } |
| 291 | |
| 292 | static inline void lock_buffer(struct buffer_head *bh) |
| 293 | { |
| 294 | might_sleep(); |
| 295 | if (test_set_buffer_locked(bh)) |
| 296 | __lock_buffer(bh); |
| 297 | } |
| 298 | |
| 299 | #endif /* _LINUX_BUFFER_HEAD_H */ |