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>
33 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
36 XBRW_READ = 1, /* transfer into target memory */
37 XBRW_WRITE = 2, /* transfer from target memory */
38 XBRW_ZERO = 3, /* Zero target memory */
41 #define XBF_READ (1 << 0) /* buffer intended for reading from device */
42 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
43 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
44 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
45 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
46 #define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
48 /* I/O hints for the BIO layer */
49 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
50 #define XBF_FUA (1 << 11)/* force cache write through mode */
51 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
53 /* flags used only as arguments to access routines */
54 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
55 #define XBF_UNMAPPED (1 << 17)/* do not map the buffer */
57 /* flags used only internally */
58 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
59 #define _XBF_KMEM (1 << 21)/* backed by heap memory */
60 #define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
61 #define _XBF_COMPOUND (1 << 23)/* compound buffer */
62 #define _XBF_LRU_DISPOSE (1 << 24)/* buffer being discarded */
64 typedef unsigned int xfs_buf_flags_t;
66 #define XFS_BUF_FLAGS \
67 { XBF_READ, "READ" }, \
68 { XBF_WRITE, "WRITE" }, \
69 { XBF_READ_AHEAD, "READ_AHEAD" }, \
70 { XBF_ASYNC, "ASYNC" }, \
71 { XBF_DONE, "DONE" }, \
72 { XBF_STALE, "STALE" }, \
73 { XBF_SYNCIO, "SYNCIO" }, \
75 { XBF_FLUSH, "FLUSH" }, \
76 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
77 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
78 { _XBF_PAGES, "PAGES" }, \
79 { _XBF_KMEM, "KMEM" }, \
80 { _XBF_DELWRI_Q, "DELWRI_Q" }, \
81 { _XBF_COMPOUND, "COMPOUND" }, \
82 { _XBF_LRU_DISPOSE, "LRU_DISPOSE" }
84 typedef struct xfs_buftarg {
86 struct block_device *bt_bdev;
87 struct backing_dev_info *bt_bdi;
88 struct xfs_mount *bt_mount;
89 unsigned int bt_bsize;
90 unsigned int bt_sshift;
93 /* LRU control structures */
94 struct shrinker bt_shrinker;
95 struct list_head bt_lru;
96 spinlock_t bt_lru_lock;
97 unsigned int bt_lru_nr;
101 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
107 xfs_daddr_t bm_bn; /* block number for I/O */
108 int bm_len; /* size of I/O */
111 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
112 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
114 typedef struct xfs_buf {
116 * first cacheline holds all the fields needed for an uncontended cache
117 * hit to be fully processed. The semaphore straddles the cacheline
118 * boundary, but the counter and lock sits on the first cacheline,
119 * which is the only bit that is touched if we hit the semaphore
120 * fast-path on locking.
122 struct rb_node b_rbnode; /* rbtree node */
123 xfs_daddr_t b_bn; /* block number of buffer */
124 int b_length; /* size of buffer in BBs */
125 atomic_t b_hold; /* reference count */
126 atomic_t b_lru_ref; /* lru reclaim ref count */
127 xfs_buf_flags_t b_flags; /* status flags */
128 struct semaphore b_sema; /* semaphore for lockables */
131 * concurrent access to b_lru and b_lru_flags are protected by
132 * bt_lru_lock and not by b_sema
134 struct list_head b_lru; /* lru list */
135 xfs_buf_flags_t b_lru_flags; /* internal lru status flags */
136 wait_queue_head_t b_waiters; /* unpin waiters */
137 struct list_head b_list;
138 struct xfs_perag *b_pag; /* contains rbtree root */
139 xfs_buftarg_t *b_target; /* buffer target (device) */
140 void *b_addr; /* virtual address of buffer */
141 struct work_struct b_iodone_work;
142 xfs_buf_iodone_t b_iodone; /* I/O completion function */
143 struct completion b_iowait; /* queue for I/O waiters */
145 struct xfs_trans *b_transp;
146 struct page **b_pages; /* array of page pointers */
147 struct page *b_page_array[XB_PAGES]; /* inline pages */
148 struct xfs_buf_map *b_maps; /* compound buffer map */
149 struct xfs_buf_map b_map; /* inline compound buffer map */
151 int b_io_length; /* IO size in BBs */
152 atomic_t b_pin_count; /* pin count */
153 atomic_t b_io_remaining; /* #outstanding I/O requests */
154 unsigned int b_page_count; /* size of page array */
155 unsigned int b_offset; /* page offset in first page */
156 unsigned short b_error; /* error code on I/O */
158 void (*b_pre_io)(struct xfs_buf *);
159 /* pre-io callback function */
161 #ifdef XFS_BUF_LOCK_TRACKING
166 /* Finding and Reading Buffers */
167 struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target,
168 struct xfs_buf_map *map, int nmaps,
169 xfs_buf_flags_t flags, struct xfs_buf *new_bp);
171 static inline struct xfs_buf *
173 struct xfs_buftarg *target,
176 xfs_buf_flags_t flags)
178 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
179 return _xfs_buf_find(target, &map, 1, flags, NULL);
182 struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target,
183 struct xfs_buf_map *map, int nmaps,
184 xfs_buf_flags_t flags);
186 static inline struct xfs_buf *
188 struct xfs_buftarg *target,
191 xfs_buf_flags_t flags)
193 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
194 return _xfs_buf_alloc(target, &map, 1, flags);
197 struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target,
198 struct xfs_buf_map *map, int nmaps,
199 xfs_buf_flags_t flags);
200 struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target,
201 struct xfs_buf_map *map, int nmaps,
202 xfs_buf_flags_t flags, xfs_buf_iodone_t verify);
203 void xfs_buf_readahead_map(struct xfs_buftarg *target,
204 struct xfs_buf_map *map, int nmaps,
205 xfs_buf_iodone_t verify);
207 static inline struct xfs_buf *
209 struct xfs_buftarg *target,
212 xfs_buf_flags_t flags)
214 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
215 return xfs_buf_get_map(target, &map, 1, flags);
218 static inline struct xfs_buf *
220 struct xfs_buftarg *target,
223 xfs_buf_flags_t flags,
224 xfs_buf_iodone_t verify)
226 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
227 return xfs_buf_read_map(target, &map, 1, flags, verify);
232 struct xfs_buftarg *target,
235 xfs_buf_iodone_t verify)
237 DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
238 return xfs_buf_readahead_map(target, &map, 1, verify);
241 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
242 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
243 int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
245 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
247 struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
248 xfs_daddr_t daddr, size_t numblks, int flags,
249 xfs_buf_iodone_t verify);
250 void xfs_buf_hold(struct xfs_buf *bp);
252 /* Releasing Buffers */
253 extern void xfs_buf_free(xfs_buf_t *);
254 extern void xfs_buf_rele(xfs_buf_t *);
256 /* Locking and Unlocking Buffers */
257 extern int xfs_buf_trylock(xfs_buf_t *);
258 extern void xfs_buf_lock(xfs_buf_t *);
259 extern void xfs_buf_unlock(xfs_buf_t *);
260 #define xfs_buf_islocked(bp) \
261 ((bp)->b_sema.count <= 0)
263 /* Buffer Read and Write Routines */
264 extern int xfs_bwrite(struct xfs_buf *bp);
266 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *);
268 extern void xfs_buf_ioend(xfs_buf_t *, int);
269 extern void xfs_buf_ioerror(xfs_buf_t *, int);
270 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
271 extern void xfs_buf_iorequest(xfs_buf_t *);
272 extern int xfs_buf_iowait(xfs_buf_t *);
273 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
275 #define xfs_buf_zero(bp, off, len) \
276 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
278 static inline int xfs_buf_geterror(xfs_buf_t *bp)
280 return bp ? bp->b_error : ENOMEM;
283 /* Buffer Utility Routines */
284 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
286 /* Delayed Write Buffer Routines */
287 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
288 extern int xfs_buf_delwri_submit(struct list_head *);
289 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
291 /* Buffer Daemon Setup Routines */
292 extern int xfs_buf_init(void);
293 extern void xfs_buf_terminate(void);
295 #define XFS_BUF_ZEROFLAGS(bp) \
296 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
297 XBF_SYNCIO|XBF_FUA|XBF_FLUSH))
299 void xfs_buf_stale(struct xfs_buf *bp);
300 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
301 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
303 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
304 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
305 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
307 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
308 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
309 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
311 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
312 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
313 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
315 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
316 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
317 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
320 * These macros use the IO block map rather than b_bn. b_bn is now really
321 * just for the buffer cache index for cached buffers. As IO does not use b_bn
322 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO
323 * map directly. Uncached buffers are not allowed to be discontiguous, so this
326 * In future, uncached buffers will pass the block number directly to the io
327 * request function and hence these macros will go away at that point.
329 #define XFS_BUF_ADDR(bp) ((bp)->b_map.bm_bn)
330 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_map.bm_bn = (xfs_daddr_t)(bno))
332 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
334 atomic_set(&bp->b_lru_ref, lru_ref);
337 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
339 return atomic_read(&bp->b_pin_count);
342 static inline void xfs_buf_relse(xfs_buf_t *bp)
349 * Handling of buftargs.
351 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
352 struct block_device *, int, const char *);
353 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
354 extern void xfs_wait_buftarg(xfs_buftarg_t *);
355 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
357 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
358 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
360 #endif /* __XFS_BUF_H__ */