2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 #include <linux/list.h>
22 #include <linux/types.h>
23 #include <linux/spinlock.h>
26 #include <linux/buffer_head.h>
27 #include <linux/uio.h>
28 #include <linux/list_lru.h>
34 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
37 XBRW_READ = 1, /* transfer into target memory */
38 XBRW_WRITE = 2, /* transfer from target memory */
39 XBRW_ZERO = 3, /* Zero target memory */
42 #define XBF_READ (1 << 0) /* buffer intended for reading from device */
43 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
44 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
45 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
46 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
47 #define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
48 #define XBF_WRITE_FAIL (1 << 24)/* async writes have failed on this buffer */
50 /* I/O hints for the BIO layer */
51 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
52 #define XBF_FUA (1 << 11)/* force cache write through mode */
53 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
55 /* flags used only as arguments to access routines */
56 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
57 #define XBF_UNMAPPED (1 << 17)/* do not map the buffer */
59 /* flags used only internally */
60 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
61 #define _XBF_KMEM (1 << 21)/* backed by heap memory */
62 #define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
63 #define _XBF_COMPOUND (1 << 23)/* compound buffer */
65 typedef unsigned int xfs_buf_flags_t;
67 #define XFS_BUF_FLAGS \
68 { XBF_READ, "READ" }, \
69 { XBF_WRITE, "WRITE" }, \
70 { XBF_READ_AHEAD, "READ_AHEAD" }, \
71 { XBF_ASYNC, "ASYNC" }, \
72 { XBF_DONE, "DONE" }, \
73 { XBF_STALE, "STALE" }, \
74 { XBF_WRITE_FAIL, "WRITE_FAIL" }, \
75 { XBF_SYNCIO, "SYNCIO" }, \
77 { XBF_FLUSH, "FLUSH" }, \
78 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
79 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
80 { _XBF_PAGES, "PAGES" }, \
81 { _XBF_KMEM, "KMEM" }, \
82 { _XBF_DELWRI_Q, "DELWRI_Q" }, \
83 { _XBF_COMPOUND, "COMPOUND" }
87 * Internal state flags.
89 #define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */
91 typedef struct xfs_buftarg {
93 struct block_device *bt_bdev;
94 struct backing_dev_info *bt_bdi;
95 struct xfs_mount *bt_mount;
96 unsigned int bt_bsize;
97 unsigned int bt_sshift;
100 /* LRU control structures */
101 struct shrinker bt_shrinker;
102 struct list_lru bt_lru;
106 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
112 xfs_daddr_t bm_bn; /* block number for I/O */
113 int bm_len; /* size of I/O */
116 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
117 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
120 void (*verify_read)(struct xfs_buf *);
121 void (*verify_write)(struct xfs_buf *);
124 typedef struct xfs_buf {
126 * first cacheline holds all the fields needed for an uncontended cache
127 * hit to be fully processed. The semaphore straddles the cacheline
128 * boundary, but the counter and lock sits on the first cacheline,
129 * which is the only bit that is touched if we hit the semaphore
130 * fast-path on locking.
132 struct rb_node b_rbnode; /* rbtree node */
133 xfs_daddr_t b_bn; /* block number of buffer */
134 int b_length; /* size of buffer in BBs */
135 atomic_t b_hold; /* reference count */
136 atomic_t b_lru_ref; /* lru reclaim ref count */
137 xfs_buf_flags_t b_flags; /* status flags */
138 struct semaphore b_sema; /* semaphore for lockables */
141 * concurrent access to b_lru and b_lru_flags are protected by
142 * bt_lru_lock and not by b_sema
144 struct list_head b_lru; /* lru list */
145 spinlock_t b_lock; /* internal state lock */
146 unsigned int b_state; /* internal state flags */
147 wait_queue_head_t b_waiters; /* unpin waiters */
148 struct list_head b_list;
149 struct xfs_perag *b_pag; /* contains rbtree root */
150 xfs_buftarg_t *b_target; /* buffer target (device) */
151 void *b_addr; /* virtual address of buffer */
152 struct work_struct b_iodone_work;
153 xfs_buf_iodone_t b_iodone; /* I/O completion function */
154 struct completion b_iowait; /* queue for I/O waiters */
156 struct xfs_trans *b_transp;
157 struct page **b_pages; /* array of page pointers */
158 struct page *b_page_array[XB_PAGES]; /* inline pages */
159 struct xfs_buf_map *b_maps; /* compound buffer map */
160 struct xfs_buf_map __b_map; /* inline compound buffer map */
162 int b_io_length; /* IO size in BBs */
163 atomic_t b_pin_count; /* pin count */
164 atomic_t b_io_remaining; /* #outstanding I/O requests */
165 unsigned int b_page_count; /* size of page array */
166 unsigned int b_offset; /* page offset in first page */
167 unsigned short b_error; /* error code on I/O */
168 const struct xfs_buf_ops *b_ops;
170 #ifdef XFS_BUF_LOCK_TRACKING
175 /* Finding and Reading Buffers */
176 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target,
177 struct xfs_buf_map *map, int nmaps,
178 xfs_buf_flags_t flags, struct xfs_buf *new_bp);
180 static inline struct xfs_buf *
182 struct xfs_buftarg *target,
185 xfs_buf_flags_t flags)
187 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
188 return _xfs_buf_find(target, &map, 1, flags, NULL);
191 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target,
192 struct xfs_buf_map *map, int nmaps,
193 xfs_buf_flags_t flags);
195 static inline struct xfs_buf *
197 struct xfs_buftarg *target,
200 xfs_buf_flags_t flags)
202 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
203 return _xfs_buf_alloc(target, &map, 1, flags);
206 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target,
207 struct xfs_buf_map *map, int nmaps,
208 xfs_buf_flags_t flags);
209 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target,
210 struct xfs_buf_map *map, int nmaps,
211 xfs_buf_flags_t flags,
212 const struct xfs_buf_ops *ops);
213 void xfs_buf_readahead_map(struct xfs_buftarg *target,
214 struct xfs_buf_map *map, int nmaps,
215 const struct xfs_buf_ops *ops);
217 static inline struct xfs_buf *
219 struct xfs_buftarg *target,
222 xfs_buf_flags_t flags)
224 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
225 return xfs_buf_get_map(target, &map, 1, flags);
228 static inline struct xfs_buf *
230 struct xfs_buftarg *target,
233 xfs_buf_flags_t flags,
234 const struct xfs_buf_ops *ops)
236 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
237 return xfs_buf_read_map(target, &map, 1, flags, ops);
242 struct xfs_buftarg *target,
245 const struct xfs_buf_ops *ops)
247 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
248 return xfs_buf_readahead_map(target, &map, 1, ops);
251 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
252 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
253 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
255 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
257 struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
258 xfs_daddr_t daddr, size_t numblks, int flags,
259 const struct xfs_buf_ops *ops);
260 void xfs_buf_hold(struct xfs_buf *bp);
262 /* Releasing Buffers */
263 extern void xfs_buf_free(xfs_buf_t *);
264 extern void xfs_buf_rele(xfs_buf_t *);
266 /* Locking and Unlocking Buffers */
267 extern int xfs_buf_trylock(xfs_buf_t *);
268 extern void xfs_buf_lock(xfs_buf_t *);
269 extern void xfs_buf_unlock(xfs_buf_t *);
270 #define xfs_buf_islocked(bp) \
271 ((bp)->b_sema.count <= 0)
273 /* Buffer Read and Write Routines */
274 extern int xfs_bwrite(struct xfs_buf *bp);
275 extern void xfs_buf_ioend(xfs_buf_t *, int);
276 extern void xfs_buf_ioerror(xfs_buf_t *, int);
277 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
278 extern void xfs_buf_iorequest(xfs_buf_t *);
279 extern int xfs_buf_iowait(xfs_buf_t *);
280 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
282 #define xfs_buf_zero(bp, off, len) \
283 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
285 extern int xfs_bioerror_relse(struct xfs_buf *);
287 static inline int xfs_buf_geterror(xfs_buf_t *bp)
289 return bp ? bp->b_error : ENOMEM;
292 /* Buffer Utility Routines */
293 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
295 /* Delayed Write Buffer Routines */
296 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
297 extern int xfs_buf_delwri_submit(struct list_head *);
298 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
300 /* Buffer Daemon Setup Routines */
301 extern int xfs_buf_init(void);
302 extern void xfs_buf_terminate(void);
304 #define XFS_BUF_ZEROFLAGS(bp) \
305 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
306 XBF_SYNCIO|XBF_FUA|XBF_FLUSH| \
309 void xfs_buf_stale(struct xfs_buf *bp);
310 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
311 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
313 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
314 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
315 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
317 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
318 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
319 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
321 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
322 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
323 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
325 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
326 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
327 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
330 * These macros use the IO block map rather than b_bn. b_bn is now really
331 * just for the buffer cache index for cached buffers. As IO does not use b_bn
332 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO
333 * map directly. Uncached buffers are not allowed to be discontiguous, so this
336 * In future, uncached buffers will pass the block number directly to the io
337 * request function and hence these macros will go away at that point.
339 #define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn)
340 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno))
342 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
344 atomic_set(&bp->b_lru_ref, lru_ref);
347 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
349 return atomic_read(&bp->b_pin_count);
352 static inline void xfs_buf_relse(xfs_buf_t *bp)
359 * Handling of buftargs.
361 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
362 struct block_device *, int, const char *);
363 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
364 extern void xfs_wait_buftarg(xfs_buftarg_t *);
365 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
367 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
368 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
370 #endif /* __XFS_BUF_H__ */