1 /*
2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
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.
8 *
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.
13 *
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
17 */
18 #ifndef __XFS_BUF_H__
19 #define __XFS_BUF_H__
20
21 #include <linux/list.h>
22 #include <linux/types.h>
23 #include <linux/spinlock.h>
24 #include <linux/mm.h>
25 #include <linux/fs.h>
26 #include <linux/buffer_head.h>
27 #include <linux/uio.h>
28
29 /*
30 * Base types
31 */
32
33 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
34
35 #define xfs_buf_ctob(pp) ((pp) * PAGE_CACHE_SIZE)
36 #define xfs_buf_btoc(dd) (((dd) + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT)
37 #define xfs_buf_btoct(dd) ((dd) >> PAGE_CACHE_SHIFT)
38 #define xfs_buf_poff(aa) ((aa) & ~PAGE_CACHE_MASK)
39
40 typedef enum {
41 XBRW_READ = 1, /* transfer into target memory */
42 XBRW_WRITE = 2, /* transfer from target memory */
43 XBRW_ZERO = 3, /* Zero target memory */
44 } xfs_buf_rw_t;
45
46 #define XBF_READ (1 << 0) /* buffer intended for reading from device */
47 #define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
48 #define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
49 #define XBF_MAPPED (1 << 3) /* buffer mapped (b_addr valid) */
50 #define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
51 #define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
52 #define XBF_DELWRI (1 << 6) /* buffer has dirty pages */
53 #define XBF_STALE (1 << 7) /* buffer has been staled, do not find it */
54
55 /* I/O hints for the BIO layer */
56 #define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
57 #define XBF_FUA (1 << 11)/* force cache write through mode */
58 #define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
59
60 /* flags used only as arguments to access routines */
61 #define XBF_LOCK (1 << 15)/* lock requested */
62 #define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
63 #define XBF_DONT_BLOCK (1 << 17)/* do not block in current thread */
64
65 /* flags used only internally */
66 #define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
67 #define _XBF_KMEM (1 << 21)/* backed by heap memory */
68 #define _XBF_DELWRI_Q (1 << 22)/* buffer on delwri queue */
69
70 typedef unsigned int xfs_buf_flags_t;
71
72 #define XFS_BUF_FLAGS \
73 { XBF_READ, "READ" }, \
74 { XBF_WRITE, "WRITE" }, \
75 { XBF_READ_AHEAD, "READ_AHEAD" }, \
76 { XBF_MAPPED, "MAPPED" }, \
77 { XBF_ASYNC, "ASYNC" }, \
78 { XBF_DONE, "DONE" }, \
79 { XBF_DELWRI, "DELWRI" }, \
80 { XBF_STALE, "STALE" }, \
81 { XBF_SYNCIO, "SYNCIO" }, \
82 { XBF_FUA, "FUA" }, \
83 { XBF_FLUSH, "FLUSH" }, \
84 { XBF_LOCK, "LOCK" }, /* should never be set */\
85 { XBF_TRYLOCK, "TRYLOCK" }, /* ditto */\
86 { XBF_DONT_BLOCK, "DONT_BLOCK" }, /* ditto */\
87 { _XBF_PAGES, "PAGES" }, \
88 { _XBF_KMEM, "KMEM" }, \
89 { _XBF_DELWRI_Q, "DELWRI_Q" }
90
91 typedef enum {
92 XBT_FORCE_FLUSH = 0,
93 } xfs_buftarg_flags_t;
94
95 typedef struct xfs_buftarg {
96 dev_t bt_dev;
97 struct block_device *bt_bdev;
98 struct backing_dev_info *bt_bdi;
99 struct xfs_mount *bt_mount;
100 unsigned int bt_bsize;
101 unsigned int bt_sshift;
102 size_t bt_smask;
103
104 /* per device delwri queue */
105 struct task_struct *bt_task;
106 struct list_head bt_delwri_queue;
107 spinlock_t bt_delwri_lock;
108 unsigned long bt_flags;
109
110 /* LRU control structures */
111 struct shrinker bt_shrinker;
112 struct list_head bt_lru;
113 spinlock_t bt_lru_lock;
114 unsigned int bt_lru_nr;
115 } xfs_buftarg_t;
116
117 struct xfs_buf;
118 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
119
120 #define XB_PAGES 2
121
122 typedef struct xfs_buf {
123 /*
124 * first cacheline holds all the fields needed for an uncontended cache
125 * hit to be fully processed. The semaphore straddles the cacheline
126 * boundary, but the counter and lock sits on the first cacheline,
127 * which is the only bit that is touched if we hit the semaphore
128 * fast-path on locking.
129 */
130 struct rb_node b_rbnode; /* rbtree node */
131 xfs_off_t b_file_offset; /* offset in file */
132 size_t b_buffer_length;/* size of buffer in bytes */
133 atomic_t b_hold; /* reference count */
134 atomic_t b_lru_ref; /* lru reclaim ref count */
135 xfs_buf_flags_t b_flags; /* status flags */
136 struct semaphore b_sema; /* semaphore for lockables */
137
138 struct list_head b_lru; /* lru list */
139 wait_queue_head_t b_waiters; /* unpin waiters */
140 struct list_head b_list;
141 struct xfs_perag *b_pag; /* contains rbtree root */
142 xfs_buftarg_t *b_target; /* buffer target (device) */
143 xfs_daddr_t b_bn; /* block number for I/O */
144 size_t b_count_desired;/* desired transfer size */
145 void *b_addr; /* virtual address of buffer */
146 struct work_struct b_iodone_work;
147 xfs_buf_iodone_t b_iodone; /* I/O completion function */
148 struct completion b_iowait; /* queue for I/O waiters */
149 void *b_fspriv;
150 struct xfs_trans *b_transp;
151 struct page **b_pages; /* array of page pointers */
152 struct page *b_page_array[XB_PAGES]; /* inline pages */
153 unsigned long b_queuetime; /* time buffer was queued */
154 atomic_t b_pin_count; /* pin count */
155 atomic_t b_io_remaining; /* #outstanding I/O requests */
156 unsigned int b_page_count; /* size of page array */
157 unsigned int b_offset; /* page offset in first page */
158 unsigned short b_error; /* error code on I/O */
159 #ifdef XFS_BUF_LOCK_TRACKING
160 int b_last_holder;
161 #endif
162 } xfs_buf_t;
163
164
165 /* Finding and Reading Buffers */
166 extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t,
167 xfs_buf_flags_t, xfs_buf_t *);
168 #define xfs_incore(buftarg,blkno,len,lockit) \
169 _xfs_buf_find(buftarg, blkno ,len, lockit, NULL)
170
171 extern xfs_buf_t *xfs_buf_get(xfs_buftarg_t *, xfs_off_t, size_t,
172 xfs_buf_flags_t);
173 extern xfs_buf_t *xfs_buf_read(xfs_buftarg_t *, xfs_off_t, size_t,
174 xfs_buf_flags_t);
175
176 struct xfs_buf *xfs_buf_alloc(struct xfs_buftarg *, xfs_off_t, size_t,
177 xfs_buf_flags_t);
178 extern void xfs_buf_set_empty(struct xfs_buf *bp, size_t len);
179 extern xfs_buf_t *xfs_buf_get_uncached(struct xfs_buftarg *, size_t, int);
180 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t);
181 extern void xfs_buf_hold(xfs_buf_t *);
182 extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t);
183 struct xfs_buf *xfs_buf_read_uncached(struct xfs_mount *mp,
184 struct xfs_buftarg *target,
185 xfs_daddr_t daddr, size_t length, int flags);
186
187 /* Releasing Buffers */
188 extern void xfs_buf_free(xfs_buf_t *);
189 extern void xfs_buf_rele(xfs_buf_t *);
190
191 /* Locking and Unlocking Buffers */
192 extern int xfs_buf_trylock(xfs_buf_t *);
193 extern void xfs_buf_lock(xfs_buf_t *);
194 extern void xfs_buf_unlock(xfs_buf_t *);
195 #define xfs_buf_islocked(bp) \
196 ((bp)->b_sema.count <= 0)
197
198 /* Buffer Read and Write Routines */
199 extern int xfs_bwrite(struct xfs_buf *bp);
200
201 extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *);
202 extern int xfs_bdstrat_cb(struct xfs_buf *);
203
204 extern void xfs_buf_ioend(xfs_buf_t *, int);
205 extern void xfs_buf_ioerror(xfs_buf_t *, int);
206 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
207 extern int xfs_buf_iorequest(xfs_buf_t *);
208 extern int xfs_buf_iowait(xfs_buf_t *);
209 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
210 xfs_buf_rw_t);
211 #define xfs_buf_zero(bp, off, len) \
212 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
213
xfs_buf_geterror(xfs_buf_t * bp)214 static inline int xfs_buf_geterror(xfs_buf_t *bp)
215 {
216 return bp ? bp->b_error : ENOMEM;
217 }
218
219 /* Buffer Utility Routines */
220 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
221
222 /* Delayed Write Buffer Routines */
223 extern void xfs_buf_delwri_queue(struct xfs_buf *);
224 extern void xfs_buf_delwri_dequeue(struct xfs_buf *);
225 extern void xfs_buf_delwri_promote(struct xfs_buf *);
226
227 /* Buffer Daemon Setup Routines */
228 extern int xfs_buf_init(void);
229 extern void xfs_buf_terminate(void);
230
231 #define XFS_BUF_ZEROFLAGS(bp) \
232 ((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI| \
233 XBF_SYNCIO|XBF_FUA|XBF_FLUSH))
234
235 void xfs_buf_stale(struct xfs_buf *bp);
236 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
237 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
238
239 #define XFS_BUF_ISDELAYWRITE(bp) ((bp)->b_flags & XBF_DELWRI)
240
241 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
242 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
243 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
244
245 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
246 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
247 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
248
249 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
250 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
251 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
252
253 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
254 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
255 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
256
257 #define XFS_BUF_ADDR(bp) ((bp)->b_bn)
258 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno))
259 #define XFS_BUF_OFFSET(bp) ((bp)->b_file_offset)
260 #define XFS_BUF_SET_OFFSET(bp, off) ((bp)->b_file_offset = (off))
261 #define XFS_BUF_COUNT(bp) ((bp)->b_count_desired)
262 #define XFS_BUF_SET_COUNT(bp, cnt) ((bp)->b_count_desired = (cnt))
263 #define XFS_BUF_SIZE(bp) ((bp)->b_buffer_length)
264 #define XFS_BUF_SET_SIZE(bp, cnt) ((bp)->b_buffer_length = (cnt))
265
xfs_buf_set_ref(struct xfs_buf * bp,int lru_ref)266 static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
267 {
268 atomic_set(&bp->b_lru_ref, lru_ref);
269 }
270
xfs_buf_ispinned(struct xfs_buf * bp)271 static inline int xfs_buf_ispinned(struct xfs_buf *bp)
272 {
273 return atomic_read(&bp->b_pin_count);
274 }
275
xfs_buf_relse(xfs_buf_t * bp)276 static inline void xfs_buf_relse(xfs_buf_t *bp)
277 {
278 xfs_buf_unlock(bp);
279 xfs_buf_rele(bp);
280 }
281
282 /*
283 * Handling of buftargs.
284 */
285 extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
286 struct block_device *, int, const char *);
287 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
288 extern void xfs_wait_buftarg(xfs_buftarg_t *);
289 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
290 extern int xfs_flush_buftarg(xfs_buftarg_t *, int);
291
292 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
293 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
294
295 #endif /* __XFS_BUF_H__ */
296