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 */
63 typedef unsigned int xfs_buf_flags_t
;
65 #define XFS_BUF_FLAGS \
66 { XBF_READ, "READ" }, \
67 { XBF_WRITE, "WRITE" }, \
68 { XBF_READ_AHEAD, "READ_AHEAD" }, \
69 { XBF_ASYNC, "ASYNC" }, \
70 { XBF_DONE, "DONE" }, \
71 { XBF_STALE, "STALE" }, \
72 { XBF_SYNCIO, "SYNCIO" }, \
74 { XBF_FLUSH, "FLUSH" }, \
75 { XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
76 { XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
77 { _XBF_PAGES, "PAGES" }, \
78 { _XBF_KMEM, "KMEM" }, \
79 { _XBF_DELWRI_Q, "DELWRI_Q" }, \
80 { _XBF_COMPOUND, "COMPOUND" }
82 typedef struct xfs_buftarg
{
84 struct block_device
*bt_bdev
;
85 struct backing_dev_info
*bt_bdi
;
86 struct xfs_mount
*bt_mount
;
87 unsigned int bt_bsize
;
88 unsigned int bt_sshift
;
91 /* LRU control structures */
92 struct shrinker bt_shrinker
;
93 struct list_head bt_lru
;
94 spinlock_t bt_lru_lock
;
95 unsigned int bt_lru_nr
;
99 typedef void (*xfs_buf_iodone_t
)(struct xfs_buf
*);
104 xfs_daddr_t bm_bn
; /* block number for I/O */
105 int bm_len
; /* size of I/O */
108 #define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
109 struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
111 typedef struct xfs_buf
{
113 * first cacheline holds all the fields needed for an uncontended cache
114 * hit to be fully processed. The semaphore straddles the cacheline
115 * boundary, but the counter and lock sits on the first cacheline,
116 * which is the only bit that is touched if we hit the semaphore
117 * fast-path on locking.
119 struct rb_node b_rbnode
; /* rbtree node */
120 xfs_daddr_t b_bn
; /* block number of buffer */
121 int b_length
; /* size of buffer in BBs */
122 atomic_t b_hold
; /* reference count */
123 atomic_t b_lru_ref
; /* lru reclaim ref count */
124 xfs_buf_flags_t b_flags
; /* status flags */
125 struct semaphore b_sema
; /* semaphore for lockables */
127 struct list_head b_lru
; /* lru list */
128 wait_queue_head_t b_waiters
; /* unpin waiters */
129 struct list_head b_list
;
130 struct xfs_perag
*b_pag
; /* contains rbtree root */
131 xfs_buftarg_t
*b_target
; /* buffer target (device) */
132 void *b_addr
; /* virtual address of buffer */
133 struct work_struct b_iodone_work
;
134 xfs_buf_iodone_t b_iodone
; /* I/O completion function */
135 struct completion b_iowait
; /* queue for I/O waiters */
137 struct xfs_trans
*b_transp
;
138 struct page
**b_pages
; /* array of page pointers */
139 struct page
*b_page_array
[XB_PAGES
]; /* inline pages */
140 struct xfs_buf_map
*b_maps
; /* compound buffer map */
141 struct xfs_buf_map b_map
; /* inline compound buffer map */
143 int b_io_length
; /* IO size in BBs */
144 atomic_t b_pin_count
; /* pin count */
145 atomic_t b_io_remaining
; /* #outstanding I/O requests */
146 unsigned int b_page_count
; /* size of page array */
147 unsigned int b_offset
; /* page offset in first page */
148 unsigned short b_error
; /* error code on I/O */
150 #ifdef XFS_BUF_LOCK_TRACKING
156 /* Finding and Reading Buffers */
157 struct xfs_buf
*_xfs_buf_find(struct xfs_buftarg
*target
,
158 struct xfs_buf_map
*map
, int nmaps
,
159 xfs_buf_flags_t flags
, struct xfs_buf
*new_bp
);
161 static inline struct xfs_buf
*
163 struct xfs_buftarg
*target
,
166 xfs_buf_flags_t flags
)
168 DEFINE_SINGLE_BUF_MAP(map
, blkno
, numblks
);
169 return _xfs_buf_find(target
, &map
, 1, flags
, NULL
);
172 struct xfs_buf
*_xfs_buf_alloc(struct xfs_buftarg
*target
,
173 struct xfs_buf_map
*map
, int nmaps
,
174 xfs_buf_flags_t flags
);
176 static inline struct xfs_buf
*
178 struct xfs_buftarg
*target
,
181 xfs_buf_flags_t flags
)
183 DEFINE_SINGLE_BUF_MAP(map
, blkno
, numblks
);
184 return _xfs_buf_alloc(target
, &map
, 1, flags
);
187 struct xfs_buf
*xfs_buf_get_map(struct xfs_buftarg
*target
,
188 struct xfs_buf_map
*map
, int nmaps
,
189 xfs_buf_flags_t flags
);
190 struct xfs_buf
*xfs_buf_read_map(struct xfs_buftarg
*target
,
191 struct xfs_buf_map
*map
, int nmaps
,
192 xfs_buf_flags_t flags
);
193 void xfs_buf_readahead_map(struct xfs_buftarg
*target
,
194 struct xfs_buf_map
*map
, int nmaps
);
196 static inline struct xfs_buf
*
198 struct xfs_buftarg
*target
,
201 xfs_buf_flags_t flags
)
203 DEFINE_SINGLE_BUF_MAP(map
, blkno
, numblks
);
204 return xfs_buf_get_map(target
, &map
, 1, flags
);
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_read_map(target
, &map
, 1, flags
);
220 struct xfs_buftarg
*target
,
224 DEFINE_SINGLE_BUF_MAP(map
, blkno
, numblks
);
225 return xfs_buf_readahead_map(target
, &map
, 1);
228 struct xfs_buf
*xfs_buf_get_empty(struct xfs_buftarg
*target
, size_t numblks
);
229 void xfs_buf_set_empty(struct xfs_buf
*bp
, size_t numblks
);
230 int xfs_buf_associate_memory(struct xfs_buf
*bp
, void *mem
, size_t length
);
232 struct xfs_buf
*xfs_buf_get_uncached(struct xfs_buftarg
*target
, size_t numblks
,
234 struct xfs_buf
*xfs_buf_read_uncached(struct xfs_buftarg
*target
,
235 xfs_daddr_t daddr
, size_t numblks
, int flags
);
236 void xfs_buf_hold(struct xfs_buf
*bp
);
238 /* Releasing Buffers */
239 extern void xfs_buf_free(xfs_buf_t
*);
240 extern void xfs_buf_rele(xfs_buf_t
*);
242 /* Locking and Unlocking Buffers */
243 extern int xfs_buf_trylock(xfs_buf_t
*);
244 extern void xfs_buf_lock(xfs_buf_t
*);
245 extern void xfs_buf_unlock(xfs_buf_t
*);
246 #define xfs_buf_islocked(bp) \
247 ((bp)->b_sema.count <= 0)
249 /* Buffer Read and Write Routines */
250 extern int xfs_bwrite(struct xfs_buf
*bp
);
252 extern void xfsbdstrat(struct xfs_mount
*, struct xfs_buf
*);
254 extern void xfs_buf_ioend(xfs_buf_t
*, int);
255 extern void xfs_buf_ioerror(xfs_buf_t
*, int);
256 extern void xfs_buf_ioerror_alert(struct xfs_buf
*, const char *func
);
257 extern void xfs_buf_iorequest(xfs_buf_t
*);
258 extern int xfs_buf_iowait(xfs_buf_t
*);
259 extern void xfs_buf_iomove(xfs_buf_t
*, size_t, size_t, void *,
261 #define xfs_buf_zero(bp, off, len) \
262 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
264 static inline int xfs_buf_geterror(xfs_buf_t
*bp
)
266 return bp
? bp
->b_error
: ENOMEM
;
269 /* Buffer Utility Routines */
270 extern xfs_caddr_t
xfs_buf_offset(xfs_buf_t
*, size_t);
272 /* Delayed Write Buffer Routines */
273 extern bool xfs_buf_delwri_queue(struct xfs_buf
*, struct list_head
*);
274 extern int xfs_buf_delwri_submit(struct list_head
*);
275 extern int xfs_buf_delwri_submit_nowait(struct list_head
*);
277 /* Buffer Daemon Setup Routines */
278 extern int xfs_buf_init(void);
279 extern void xfs_buf_terminate(void);
281 #define XFS_BUF_ZEROFLAGS(bp) \
282 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
283 XBF_SYNCIO|XBF_FUA|XBF_FLUSH))
285 void xfs_buf_stale(struct xfs_buf
*bp
);
286 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
287 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
289 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
290 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
291 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
293 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
294 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
295 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
297 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
298 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
299 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
301 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
302 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
303 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
306 * These macros use the IO block map rather than b_bn. b_bn is now really
307 * just for the buffer cache index for cached buffers. As IO does not use b_bn
308 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO
309 * map directly. Uncached buffers are not allowed to be discontiguous, so this
312 * In future, uncached buffers will pass the block number directly to the io
313 * request function and hence these macros will go away at that point.
315 #define XFS_BUF_ADDR(bp) ((bp)->b_map.bm_bn)
316 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_map.bm_bn = (xfs_daddr_t)(bno))
318 static inline void xfs_buf_set_ref(struct xfs_buf
*bp
, int lru_ref
)
320 atomic_set(&bp
->b_lru_ref
, lru_ref
);
323 static inline int xfs_buf_ispinned(struct xfs_buf
*bp
)
325 return atomic_read(&bp
->b_pin_count
);
328 static inline void xfs_buf_relse(xfs_buf_t
*bp
)
335 * Handling of buftargs.
337 extern xfs_buftarg_t
*xfs_alloc_buftarg(struct xfs_mount
*,
338 struct block_device
*, int, const char *);
339 extern void xfs_free_buftarg(struct xfs_mount
*, struct xfs_buftarg
*);
340 extern void xfs_wait_buftarg(xfs_buftarg_t
*);
341 extern int xfs_setsize_buftarg(xfs_buftarg_t
*, unsigned int, unsigned int);
343 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
344 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
346 #endif /* __XFS_BUF_H__ */