Merge branch 'agp-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...
[deliverable/linux.git] / fs / xfs / linux-2.6 / xfs_buf.h
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 <asm/system.h>
25 #include <linux/mm.h>
26 #include <linux/fs.h>
27 #include <linux/buffer_head.h>
28 #include <linux/uio.h>
29
30 /*
31 * Base types
32 */
33
34 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
35
36 #define xfs_buf_ctob(pp) ((pp) * PAGE_CACHE_SIZE)
37 #define xfs_buf_btoc(dd) (((dd) + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT)
38 #define xfs_buf_btoct(dd) ((dd) >> PAGE_CACHE_SHIFT)
39 #define xfs_buf_poff(aa) ((aa) & ~PAGE_CACHE_MASK)
40
41 typedef enum {
42 XBRW_READ = 1, /* transfer into target memory */
43 XBRW_WRITE = 2, /* transfer from target memory */
44 XBRW_ZERO = 3, /* Zero target memory */
45 } xfs_buf_rw_t;
46
47 typedef enum {
48 XBF_READ = (1 << 0), /* buffer intended for reading from device */
49 XBF_WRITE = (1 << 1), /* buffer intended for writing to device */
50 XBF_MAPPED = (1 << 2), /* buffer mapped (b_addr valid) */
51 XBF_ASYNC = (1 << 4), /* initiator will not wait for completion */
52 XBF_DONE = (1 << 5), /* all pages in the buffer uptodate */
53 XBF_DELWRI = (1 << 6), /* buffer has dirty pages */
54 XBF_STALE = (1 << 7), /* buffer has been staled, do not find it */
55 XBF_FS_MANAGED = (1 << 8), /* filesystem controls freeing memory */
56 XBF_ORDERED = (1 << 11), /* use ordered writes */
57 XBF_READ_AHEAD = (1 << 12), /* asynchronous read-ahead */
58 XBF_LOG_BUFFER = (1 << 13), /* this is a buffer used for the log */
59
60 /* flags used only as arguments to access routines */
61 XBF_LOCK = (1 << 14), /* lock requested */
62 XBF_TRYLOCK = (1 << 15), /* lock requested, but do not wait */
63 XBF_DONT_BLOCK = (1 << 16), /* do not block in current thread */
64
65 /* flags used only internally */
66 _XBF_PAGE_CACHE = (1 << 17),/* backed by pagecache */
67 _XBF_PAGES = (1 << 18), /* backed by refcounted pages */
68 _XBF_RUN_QUEUES = (1 << 19),/* run block device task queue */
69 _XBF_DELWRI_Q = (1 << 21), /* buffer on delwri queue */
70
71 /*
72 * Special flag for supporting metadata blocks smaller than a FSB.
73 *
74 * In this case we can have multiple xfs_buf_t on a single page and
75 * need to lock out concurrent xfs_buf_t readers as they only
76 * serialise access to the buffer.
77 *
78 * If the FSB size >= PAGE_CACHE_SIZE case, we have no serialisation
79 * between reads of the page. Hence we can have one thread read the
80 * page and modify it, but then race with another thread that thinks
81 * the page is not up-to-date and hence reads it again.
82 *
83 * The result is that the first modifcation to the page is lost.
84 * This sort of AGF/AGI reading race can happen when unlinking inodes
85 * that require truncation and results in the AGI unlinked list
86 * modifications being lost.
87 */
88 _XBF_PAGE_LOCKED = (1 << 22),
89
90 /*
91 * If we try a barrier write, but it fails we have to communicate
92 * this to the upper layers. Unfortunately b_error gets overwritten
93 * when the buffer is re-issued so we have to add another flag to
94 * keep this information.
95 */
96 _XFS_BARRIER_FAILED = (1 << 23),
97 } xfs_buf_flags_t;
98
99 #define XFS_BUF_FLAGS \
100 { XBF_READ, "READ" }, \
101 { XBF_WRITE, "WRITE" }, \
102 { XBF_MAPPED, "MAPPED" }, \
103 { XBF_ASYNC, "ASYNC" }, \
104 { XBF_DONE, "DONE" }, \
105 { XBF_DELWRI, "DELWRI" }, \
106 { XBF_STALE, "STALE" }, \
107 { XBF_FS_MANAGED, "FS_MANAGED" }, \
108 { XBF_ORDERED, "ORDERED" }, \
109 { XBF_READ_AHEAD, "READ_AHEAD" }, \
110 { XBF_LOCK, "LOCK" }, /* should never be set */\
111 { XBF_TRYLOCK, "TRYLOCK" }, /* ditto */\
112 { XBF_DONT_BLOCK, "DONT_BLOCK" }, /* ditto */\
113 { _XBF_PAGE_CACHE, "PAGE_CACHE" }, \
114 { _XBF_PAGES, "PAGES" }, \
115 { _XBF_RUN_QUEUES, "RUN_QUEUES" }, \
116 { _XBF_DELWRI_Q, "DELWRI_Q" }, \
117 { _XBF_PAGE_LOCKED, "PAGE_LOCKED" }, \
118 { _XFS_BARRIER_FAILED, "BARRIER_FAILED" }
119
120
121 typedef enum {
122 XBT_FORCE_SLEEP = 0,
123 XBT_FORCE_FLUSH = 1,
124 } xfs_buftarg_flags_t;
125
126 typedef struct xfs_bufhash {
127 struct list_head bh_list;
128 spinlock_t bh_lock;
129 } xfs_bufhash_t;
130
131 typedef struct xfs_buftarg {
132 dev_t bt_dev;
133 struct block_device *bt_bdev;
134 struct address_space *bt_mapping;
135 unsigned int bt_bsize;
136 unsigned int bt_sshift;
137 size_t bt_smask;
138
139 /* per device buffer hash table */
140 uint bt_hashmask;
141 uint bt_hashshift;
142 xfs_bufhash_t *bt_hash;
143
144 /* per device delwri queue */
145 struct task_struct *bt_task;
146 struct list_head bt_list;
147 struct list_head bt_delwrite_queue;
148 spinlock_t bt_delwrite_lock;
149 unsigned long bt_flags;
150 } xfs_buftarg_t;
151
152 /*
153 * xfs_buf_t: Buffer structure for pagecache-based buffers
154 *
155 * This buffer structure is used by the pagecache buffer management routines
156 * to refer to an assembly of pages forming a logical buffer.
157 *
158 * The buffer structure is used on a temporary basis only, and discarded when
159 * released. The real data storage is recorded in the pagecache. Buffers are
160 * hashed to the block device on which the file system resides.
161 */
162
163 struct xfs_buf;
164 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
165 typedef void (*xfs_buf_relse_t)(struct xfs_buf *);
166 typedef int (*xfs_buf_bdstrat_t)(struct xfs_buf *);
167
168 #define XB_PAGES 2
169
170 typedef struct xfs_buf {
171 struct semaphore b_sema; /* semaphore for lockables */
172 unsigned long b_queuetime; /* time buffer was queued */
173 atomic_t b_pin_count; /* pin count */
174 wait_queue_head_t b_waiters; /* unpin waiters */
175 struct list_head b_list;
176 xfs_buf_flags_t b_flags; /* status flags */
177 struct list_head b_hash_list; /* hash table list */
178 xfs_bufhash_t *b_hash; /* hash table list start */
179 xfs_buftarg_t *b_target; /* buffer target (device) */
180 atomic_t b_hold; /* reference count */
181 xfs_daddr_t b_bn; /* block number for I/O */
182 xfs_off_t b_file_offset; /* offset in file */
183 size_t b_buffer_length;/* size of buffer in bytes */
184 size_t b_count_desired;/* desired transfer size */
185 void *b_addr; /* virtual address of buffer */
186 struct work_struct b_iodone_work;
187 atomic_t b_io_remaining; /* #outstanding I/O requests */
188 xfs_buf_iodone_t b_iodone; /* I/O completion function */
189 xfs_buf_relse_t b_relse; /* releasing function */
190 xfs_buf_bdstrat_t b_strat; /* pre-write function */
191 struct completion b_iowait; /* queue for I/O waiters */
192 void *b_fspriv;
193 void *b_fspriv2;
194 struct xfs_mount *b_mount;
195 unsigned short b_error; /* error code on I/O */
196 unsigned int b_page_count; /* size of page array */
197 unsigned int b_offset; /* page offset in first page */
198 struct page **b_pages; /* array of page pointers */
199 struct page *b_page_array[XB_PAGES]; /* inline pages */
200 #ifdef XFS_BUF_LOCK_TRACKING
201 int b_last_holder;
202 #endif
203 } xfs_buf_t;
204
205
206 /* Finding and Reading Buffers */
207 extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t,
208 xfs_buf_flags_t, xfs_buf_t *);
209 #define xfs_incore(buftarg,blkno,len,lockit) \
210 _xfs_buf_find(buftarg, blkno ,len, lockit, NULL)
211
212 extern xfs_buf_t *xfs_buf_get(xfs_buftarg_t *, xfs_off_t, size_t,
213 xfs_buf_flags_t);
214 extern xfs_buf_t *xfs_buf_read(xfs_buftarg_t *, xfs_off_t, size_t,
215 xfs_buf_flags_t);
216
217 extern xfs_buf_t *xfs_buf_get_empty(size_t, xfs_buftarg_t *);
218 extern xfs_buf_t *xfs_buf_get_noaddr(size_t, xfs_buftarg_t *);
219 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t);
220 extern void xfs_buf_hold(xfs_buf_t *);
221 extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t,
222 xfs_buf_flags_t);
223
224 /* Releasing Buffers */
225 extern void xfs_buf_free(xfs_buf_t *);
226 extern void xfs_buf_rele(xfs_buf_t *);
227
228 /* Locking and Unlocking Buffers */
229 extern int xfs_buf_cond_lock(xfs_buf_t *);
230 extern int xfs_buf_lock_value(xfs_buf_t *);
231 extern void xfs_buf_lock(xfs_buf_t *);
232 extern void xfs_buf_unlock(xfs_buf_t *);
233
234 /* Buffer Read and Write Routines */
235 extern int xfs_bawrite(void *mp, xfs_buf_t *bp);
236 extern void xfs_bdwrite(void *mp, xfs_buf_t *bp);
237 extern void xfs_buf_ioend(xfs_buf_t *, int);
238 extern void xfs_buf_ioerror(xfs_buf_t *, int);
239 extern int xfs_buf_iorequest(xfs_buf_t *);
240 extern int xfs_buf_iowait(xfs_buf_t *);
241 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, xfs_caddr_t,
242 xfs_buf_rw_t);
243
244 static inline int xfs_buf_iostrategy(xfs_buf_t *bp)
245 {
246 return bp->b_strat ? bp->b_strat(bp) : xfs_buf_iorequest(bp);
247 }
248
249 static inline int xfs_buf_geterror(xfs_buf_t *bp)
250 {
251 return bp ? bp->b_error : ENOMEM;
252 }
253
254 /* Buffer Utility Routines */
255 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
256
257 /* Pinning Buffer Storage in Memory */
258 extern void xfs_buf_pin(xfs_buf_t *);
259 extern void xfs_buf_unpin(xfs_buf_t *);
260 extern int xfs_buf_ispin(xfs_buf_t *);
261
262 /* Delayed Write Buffer Routines */
263 extern void xfs_buf_delwri_dequeue(xfs_buf_t *);
264
265 /* Buffer Daemon Setup Routines */
266 extern int xfs_buf_init(void);
267 extern void xfs_buf_terminate(void);
268
269 #define xfs_buf_target_name(target) \
270 ({ char __b[BDEVNAME_SIZE]; bdevname((target)->bt_bdev, __b); __b; })
271
272
273 #define XFS_B_ASYNC XBF_ASYNC
274 #define XFS_B_DELWRI XBF_DELWRI
275 #define XFS_B_READ XBF_READ
276 #define XFS_B_WRITE XBF_WRITE
277 #define XFS_B_STALE XBF_STALE
278
279 #define XFS_BUF_TRYLOCK XBF_TRYLOCK
280 #define XFS_INCORE_TRYLOCK XBF_TRYLOCK
281 #define XFS_BUF_LOCK XBF_LOCK
282 #define XFS_BUF_MAPPED XBF_MAPPED
283
284 #define BUF_BUSY XBF_DONT_BLOCK
285
286 #define XFS_BUF_BFLAGS(bp) ((bp)->b_flags)
287 #define XFS_BUF_ZEROFLAGS(bp) ((bp)->b_flags &= \
288 ~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI|XBF_ORDERED))
289
290 #define XFS_BUF_STALE(bp) ((bp)->b_flags |= XFS_B_STALE)
291 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XFS_B_STALE)
292 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XFS_B_STALE)
293 #define XFS_BUF_SUPER_STALE(bp) do { \
294 XFS_BUF_STALE(bp); \
295 xfs_buf_delwri_dequeue(bp); \
296 XFS_BUF_DONE(bp); \
297 } while (0)
298
299 #define XFS_BUF_MANAGE XBF_FS_MANAGED
300 #define XFS_BUF_UNMANAGE(bp) ((bp)->b_flags &= ~XBF_FS_MANAGED)
301
302 #define XFS_BUF_DELAYWRITE(bp) ((bp)->b_flags |= XBF_DELWRI)
303 #define XFS_BUF_UNDELAYWRITE(bp) xfs_buf_delwri_dequeue(bp)
304 #define XFS_BUF_ISDELAYWRITE(bp) ((bp)->b_flags & XBF_DELWRI)
305
306 #define XFS_BUF_ERROR(bp,no) xfs_buf_ioerror(bp,no)
307 #define XFS_BUF_GETERROR(bp) xfs_buf_geterror(bp)
308 #define XFS_BUF_ISERROR(bp) (xfs_buf_geterror(bp) ? 1 : 0)
309
310 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
311 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
312 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
313
314 #define XFS_BUF_BUSY(bp) do { } while (0)
315 #define XFS_BUF_UNBUSY(bp) do { } while (0)
316 #define XFS_BUF_ISBUSY(bp) (1)
317
318 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
319 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
320 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
321
322 #define XFS_BUF_ORDERED(bp) ((bp)->b_flags |= XBF_ORDERED)
323 #define XFS_BUF_UNORDERED(bp) ((bp)->b_flags &= ~XBF_ORDERED)
324 #define XFS_BUF_ISORDERED(bp) ((bp)->b_flags & XBF_ORDERED)
325
326 #define XFS_BUF_HOLD(bp) xfs_buf_hold(bp)
327 #define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
328 #define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
329 #define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
330
331 #define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
332 #define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
333 #define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
334
335 #define XFS_BUF_IODONE_FUNC(bp) ((bp)->b_iodone)
336 #define XFS_BUF_SET_IODONE_FUNC(bp, func) ((bp)->b_iodone = (func))
337 #define XFS_BUF_CLR_IODONE_FUNC(bp) ((bp)->b_iodone = NULL)
338 #define XFS_BUF_SET_BDSTRAT_FUNC(bp, func) ((bp)->b_strat = (func))
339 #define XFS_BUF_CLR_BDSTRAT_FUNC(bp) ((bp)->b_strat = NULL)
340
341 #define XFS_BUF_FSPRIVATE(bp, type) ((type)(bp)->b_fspriv)
342 #define XFS_BUF_SET_FSPRIVATE(bp, val) ((bp)->b_fspriv = (void*)(val))
343 #define XFS_BUF_FSPRIVATE2(bp, type) ((type)(bp)->b_fspriv2)
344 #define XFS_BUF_SET_FSPRIVATE2(bp, val) ((bp)->b_fspriv2 = (void*)(val))
345 #define XFS_BUF_SET_START(bp) do { } while (0)
346 #define XFS_BUF_SET_BRELSE_FUNC(bp, func) ((bp)->b_relse = (func))
347
348 #define XFS_BUF_PTR(bp) (xfs_caddr_t)((bp)->b_addr)
349 #define XFS_BUF_SET_PTR(bp, val, cnt) xfs_buf_associate_memory(bp, val, cnt)
350 #define XFS_BUF_ADDR(bp) ((bp)->b_bn)
351 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno))
352 #define XFS_BUF_OFFSET(bp) ((bp)->b_file_offset)
353 #define XFS_BUF_SET_OFFSET(bp, off) ((bp)->b_file_offset = (off))
354 #define XFS_BUF_COUNT(bp) ((bp)->b_count_desired)
355 #define XFS_BUF_SET_COUNT(bp, cnt) ((bp)->b_count_desired = (cnt))
356 #define XFS_BUF_SIZE(bp) ((bp)->b_buffer_length)
357 #define XFS_BUF_SET_SIZE(bp, cnt) ((bp)->b_buffer_length = (cnt))
358
359 #define XFS_BUF_SET_VTYPE_REF(bp, type, ref) do { } while (0)
360 #define XFS_BUF_SET_VTYPE(bp, type) do { } while (0)
361 #define XFS_BUF_SET_REF(bp, ref) do { } while (0)
362
363 #define XFS_BUF_ISPINNED(bp) xfs_buf_ispin(bp)
364
365 #define XFS_BUF_VALUSEMA(bp) xfs_buf_lock_value(bp)
366 #define XFS_BUF_CPSEMA(bp) (xfs_buf_cond_lock(bp) == 0)
367 #define XFS_BUF_VSEMA(bp) xfs_buf_unlock(bp)
368 #define XFS_BUF_PSEMA(bp,x) xfs_buf_lock(bp)
369 #define XFS_BUF_FINISH_IOWAIT(bp) complete(&bp->b_iowait);
370
371 #define XFS_BUF_SET_TARGET(bp, target) ((bp)->b_target = (target))
372 #define XFS_BUF_TARGET(bp) ((bp)->b_target)
373 #define XFS_BUFTARG_NAME(target) xfs_buf_target_name(target)
374
375 static inline void xfs_buf_relse(xfs_buf_t *bp)
376 {
377 if (!bp->b_relse)
378 xfs_buf_unlock(bp);
379 xfs_buf_rele(bp);
380 }
381
382 #define xfs_bpin(bp) xfs_buf_pin(bp)
383 #define xfs_bunpin(bp) xfs_buf_unpin(bp)
384 #define xfs_biodone(bp) xfs_buf_ioend(bp, 0)
385
386 #define xfs_biomove(bp, off, len, data, rw) \
387 xfs_buf_iomove((bp), (off), (len), (data), \
388 ((rw) == XFS_B_WRITE) ? XBRW_WRITE : XBRW_READ)
389
390 #define xfs_biozero(bp, off, len) \
391 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
392
393
394 static inline int XFS_bwrite(xfs_buf_t *bp)
395 {
396 int iowait = (bp->b_flags & XBF_ASYNC) == 0;
397 int error = 0;
398
399 if (!iowait)
400 bp->b_flags |= _XBF_RUN_QUEUES;
401
402 xfs_buf_delwri_dequeue(bp);
403 xfs_buf_iostrategy(bp);
404 if (iowait) {
405 error = xfs_buf_iowait(bp);
406 xfs_buf_relse(bp);
407 }
408 return error;
409 }
410
411 #define XFS_bdstrat(bp) xfs_buf_iorequest(bp)
412
413 #define xfs_iowait(bp) xfs_buf_iowait(bp)
414
415 #define xfs_baread(target, rablkno, ralen) \
416 xfs_buf_readahead((target), (rablkno), (ralen), XBF_DONT_BLOCK)
417
418
419 /*
420 * Handling of buftargs.
421 */
422 extern xfs_buftarg_t *xfs_alloc_buftarg(struct block_device *, int);
423 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
424 extern void xfs_wait_buftarg(xfs_buftarg_t *);
425 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
426 extern int xfs_flush_buftarg(xfs_buftarg_t *, int);
427 #ifdef CONFIG_KDB_MODULES
428 extern struct list_head *xfs_get_buftarg_list(void);
429 #endif
430
431 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
432 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
433
434 #define xfs_binval(buftarg) xfs_flush_buftarg(buftarg, 1)
435 #define XFS_bflush(buftarg) xfs_flush_buftarg(buftarg, 1)
436
437 #endif /* __XFS_BUF_H__ */
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