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
59 /* flags used only as arguments to access routines */
60 XBF_LOCK = (1 << 14), /* lock requested */
61 XBF_TRYLOCK = (1 << 15), /* lock requested, but do not wait */
62 XBF_DONT_BLOCK = (1 << 16), /* do not block in current thread */
63
64 /* flags used only internally */
65 _XBF_PAGE_CACHE = (1 << 17),/* backed by pagecache */
66 _XBF_PAGES = (1 << 18), /* backed by refcounted pages */
67 _XBF_RUN_QUEUES = (1 << 19),/* run block device task queue */
68 _XBF_DELWRI_Q = (1 << 21), /* buffer on delwri queue */
69
70 /*
71 * Special flag for supporting metadata blocks smaller than a FSB.
72 *
73 * In this case we can have multiple xfs_buf_t on a single page and
74 * need to lock out concurrent xfs_buf_t readers as they only
75 * serialise access to the buffer.
76 *
77 * If the FSB size >= PAGE_CACHE_SIZE case, we have no serialisation
78 * between reads of the page. Hence we can have one thread read the
79 * page and modify it, but then race with another thread that thinks
80 * the page is not up-to-date and hence reads it again.
81 *
82 * The result is that the first modifcation to the page is lost.
83 * This sort of AGF/AGI reading race can happen when unlinking inodes
84 * that require truncation and results in the AGI unlinked list
85 * modifications being lost.
86 */
87 _XBF_PAGE_LOCKED = (1 << 22),
88 } xfs_buf_flags_t;
89
90 typedef enum {
91 XBT_FORCE_SLEEP = 0,
92 XBT_FORCE_FLUSH = 1,
93 } xfs_buftarg_flags_t;
94
95 typedef struct xfs_bufhash {
96 struct list_head bh_list;
97 spinlock_t bh_lock;
98 } xfs_bufhash_t;
99
100 typedef struct xfs_buftarg {
101 dev_t bt_dev;
102 struct block_device *bt_bdev;
103 struct address_space *bt_mapping;
104 unsigned int bt_bsize;
105 unsigned int bt_sshift;
106 size_t bt_smask;
107
108 /* per device buffer hash table */
109 uint bt_hashmask;
110 uint bt_hashshift;
111 xfs_bufhash_t *bt_hash;
112
113 /* per device delwri queue */
114 struct task_struct *bt_task;
115 struct list_head bt_list;
116 struct list_head bt_delwrite_queue;
117 spinlock_t bt_delwrite_lock;
118 unsigned long bt_flags;
119 } xfs_buftarg_t;
120
121 /*
122 * xfs_buf_t: Buffer structure for pagecache-based buffers
123 *
124 * This buffer structure is used by the pagecache buffer management routines
125 * to refer to an assembly of pages forming a logical buffer.
126 *
127 * The buffer structure is used on a temporary basis only, and discarded when
128 * released. The real data storage is recorded in the pagecache. Buffers are
129 * hashed to the block device on which the file system resides.
130 */
131
132 struct xfs_buf;
133 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
134 typedef void (*xfs_buf_relse_t)(struct xfs_buf *);
135 typedef int (*xfs_buf_bdstrat_t)(struct xfs_buf *);
136
137 #define XB_PAGES 2
138
139 typedef struct xfs_buf {
140 struct compat_semaphore b_sema; /* semaphore for lockables */
141 unsigned long b_queuetime; /* time buffer was queued */
142 atomic_t b_pin_count; /* pin count */
143 wait_queue_head_t b_waiters; /* unpin waiters */
144 struct list_head b_list;
145 xfs_buf_flags_t b_flags; /* status flags */
146 struct list_head b_hash_list; /* hash table list */
147 xfs_bufhash_t *b_hash; /* hash table list start */
148 xfs_buftarg_t *b_target; /* buffer target (device) */
149 atomic_t b_hold; /* reference count */
150 xfs_daddr_t b_bn; /* block number for I/O */
151 xfs_off_t b_file_offset; /* offset in file */
152 size_t b_buffer_length;/* size of buffer in bytes */
153 size_t b_count_desired;/* desired transfer size */
154 void *b_addr; /* virtual address of buffer */
155 struct work_struct b_iodone_work;
156 atomic_t b_io_remaining; /* #outstanding I/O requests */
157 xfs_buf_iodone_t b_iodone; /* I/O completion function */
158 xfs_buf_relse_t b_relse; /* releasing function */
159 xfs_buf_bdstrat_t b_strat; /* pre-write function */
160 struct compat_semaphore b_iodonesema; /* Semaphore for I/O waiters */
161 void *b_fspriv;
162 void *b_fspriv2;
163 void *b_fspriv3;
164 unsigned short b_error; /* error code on I/O */
165 unsigned int b_page_count; /* size of page array */
166 unsigned int b_offset; /* page offset in first page */
167 struct page **b_pages; /* array of page pointers */
168 struct page *b_page_array[XB_PAGES]; /* inline pages */
169 #ifdef XFS_BUF_LOCK_TRACKING
170 int b_last_holder;
171 #endif
172 } xfs_buf_t;
173
174
175 /* Finding and Reading Buffers */
176 extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t,
177 xfs_buf_flags_t, xfs_buf_t *);
178 #define xfs_incore(buftarg,blkno,len,lockit) \
179 _xfs_buf_find(buftarg, blkno ,len, lockit, NULL)
180
181 extern xfs_buf_t *xfs_buf_get_flags(xfs_buftarg_t *, xfs_off_t, size_t,
182 xfs_buf_flags_t);
183 #define xfs_buf_get(target, blkno, len, flags) \
184 xfs_buf_get_flags((target), (blkno), (len), XBF_LOCK | XBF_MAPPED)
185
186 extern xfs_buf_t *xfs_buf_read_flags(xfs_buftarg_t *, xfs_off_t, size_t,
187 xfs_buf_flags_t);
188 #define xfs_buf_read(target, blkno, len, flags) \
189 xfs_buf_read_flags((target), (blkno), (len), XBF_LOCK | XBF_MAPPED)
190
191 extern xfs_buf_t *xfs_buf_get_empty(size_t, xfs_buftarg_t *);
192 extern xfs_buf_t *xfs_buf_get_noaddr(size_t, xfs_buftarg_t *);
193 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t);
194 extern void xfs_buf_hold(xfs_buf_t *);
195 extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t,
196 xfs_buf_flags_t);
197
198 /* Releasing Buffers */
199 extern void xfs_buf_free(xfs_buf_t *);
200 extern void xfs_buf_rele(xfs_buf_t *);
201
202 /* Locking and Unlocking Buffers */
203 extern int xfs_buf_cond_lock(xfs_buf_t *);
204 extern int xfs_buf_lock_value(xfs_buf_t *);
205 extern void xfs_buf_lock(xfs_buf_t *);
206 extern void xfs_buf_unlock(xfs_buf_t *);
207
208 /* Buffer Read and Write Routines */
209 extern void xfs_buf_ioend(xfs_buf_t *, int);
210 extern void xfs_buf_ioerror(xfs_buf_t *, int);
211 extern int xfs_buf_iostart(xfs_buf_t *, xfs_buf_flags_t);
212 extern int xfs_buf_iorequest(xfs_buf_t *);
213 extern int xfs_buf_iowait(xfs_buf_t *);
214 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, xfs_caddr_t,
215 xfs_buf_rw_t);
216
217 static inline int xfs_buf_iostrategy(xfs_buf_t *bp)
218 {
219 return bp->b_strat ? bp->b_strat(bp) : xfs_buf_iorequest(bp);
220 }
221
222 static inline int xfs_buf_geterror(xfs_buf_t *bp)
223 {
224 return bp ? bp->b_error : ENOMEM;
225 }
226
227 /* Buffer Utility Routines */
228 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
229
230 /* Pinning Buffer Storage in Memory */
231 extern void xfs_buf_pin(xfs_buf_t *);
232 extern void xfs_buf_unpin(xfs_buf_t *);
233 extern int xfs_buf_ispin(xfs_buf_t *);
234
235 /* Delayed Write Buffer Routines */
236 extern void xfs_buf_delwri_dequeue(xfs_buf_t *);
237
238 /* Buffer Daemon Setup Routines */
239 extern int xfs_buf_init(void);
240 extern void xfs_buf_terminate(void);
241
242 #ifdef XFS_BUF_TRACE
243 extern ktrace_t *xfs_buf_trace_buf;
244 extern void xfs_buf_trace(xfs_buf_t *, char *, void *, void *);
245 #else
246 #define xfs_buf_trace(bp,id,ptr,ra) do { } while (0)
247 #endif
248
249 #define xfs_buf_target_name(target) \
250 ({ char __b[BDEVNAME_SIZE]; bdevname((target)->bt_bdev, __b); __b; })
251
252
253 #define XFS_B_ASYNC XBF_ASYNC
254 #define XFS_B_DELWRI XBF_DELWRI
255 #define XFS_B_READ XBF_READ
256 #define XFS_B_WRITE XBF_WRITE
257 #define XFS_B_STALE XBF_STALE
258
259 #define XFS_BUF_TRYLOCK XBF_TRYLOCK
260 #define XFS_INCORE_TRYLOCK XBF_TRYLOCK
261 #define XFS_BUF_LOCK XBF_LOCK
262 #define XFS_BUF_MAPPED XBF_MAPPED
263
264 #define BUF_BUSY XBF_DONT_BLOCK
265
266 #define XFS_BUF_BFLAGS(bp) ((bp)->b_flags)
267 #define XFS_BUF_ZEROFLAGS(bp) ((bp)->b_flags &= \
268 ~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI|XBF_ORDERED))
269
270 #define XFS_BUF_STALE(bp) ((bp)->b_flags |= XFS_B_STALE)
271 #define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XFS_B_STALE)
272 #define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XFS_B_STALE)
273 #define XFS_BUF_SUPER_STALE(bp) do { \
274 XFS_BUF_STALE(bp); \
275 xfs_buf_delwri_dequeue(bp); \
276 XFS_BUF_DONE(bp); \
277 } while (0)
278
279 #define XFS_BUF_MANAGE XBF_FS_MANAGED
280 #define XFS_BUF_UNMANAGE(bp) ((bp)->b_flags &= ~XBF_FS_MANAGED)
281
282 #define XFS_BUF_DELAYWRITE(bp) ((bp)->b_flags |= XBF_DELWRI)
283 #define XFS_BUF_UNDELAYWRITE(bp) xfs_buf_delwri_dequeue(bp)
284 #define XFS_BUF_ISDELAYWRITE(bp) ((bp)->b_flags & XBF_DELWRI)
285
286 #define XFS_BUF_ERROR(bp,no) xfs_buf_ioerror(bp,no)
287 #define XFS_BUF_GETERROR(bp) xfs_buf_geterror(bp)
288 #define XFS_BUF_ISERROR(bp) (xfs_buf_geterror(bp) ? 1 : 0)
289
290 #define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
291 #define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
292 #define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
293
294 #define XFS_BUF_BUSY(bp) do { } while (0)
295 #define XFS_BUF_UNBUSY(bp) do { } while (0)
296 #define XFS_BUF_ISBUSY(bp) (1)
297
298 #define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
299 #define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
300 #define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
301
302 #define XFS_BUF_ORDERED(bp) ((bp)->b_flags |= XBF_ORDERED)
303 #define XFS_BUF_UNORDERED(bp) ((bp)->b_flags &= ~XBF_ORDERED)
304 #define XFS_BUF_ISORDERED(bp) ((bp)->b_flags & XBF_ORDERED)
305
306 #define XFS_BUF_SHUT(bp) do { } while (0)
307 #define XFS_BUF_UNSHUT(bp) do { } while (0)
308 #define XFS_BUF_ISSHUT(bp) (0)
309
310 #define XFS_BUF_HOLD(bp) xfs_buf_hold(bp)
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)
314
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)
318
319 #define XFS_BUF_IODONE_FUNC(bp) ((bp)->b_iodone)
320 #define XFS_BUF_SET_IODONE_FUNC(bp, func) ((bp)->b_iodone = (func))
321 #define XFS_BUF_CLR_IODONE_FUNC(bp) ((bp)->b_iodone = NULL)
322 #define XFS_BUF_SET_BDSTRAT_FUNC(bp, func) ((bp)->b_strat = (func))
323 #define XFS_BUF_CLR_BDSTRAT_FUNC(bp) ((bp)->b_strat = NULL)
324
325 #define XFS_BUF_FSPRIVATE(bp, type) ((type)(bp)->b_fspriv)
326 #define XFS_BUF_SET_FSPRIVATE(bp, val) ((bp)->b_fspriv = (void*)(val))
327 #define XFS_BUF_FSPRIVATE2(bp, type) ((type)(bp)->b_fspriv2)
328 #define XFS_BUF_SET_FSPRIVATE2(bp, val) ((bp)->b_fspriv2 = (void*)(val))
329 #define XFS_BUF_FSPRIVATE3(bp, type) ((type)(bp)->b_fspriv3)
330 #define XFS_BUF_SET_FSPRIVATE3(bp, val) ((bp)->b_fspriv3 = (void*)(val))
331 #define XFS_BUF_SET_START(bp) do { } while (0)
332 #define XFS_BUF_SET_BRELSE_FUNC(bp, func) ((bp)->b_relse = (func))
333
334 #define XFS_BUF_PTR(bp) (xfs_caddr_t)((bp)->b_addr)
335 #define XFS_BUF_SET_PTR(bp, val, cnt) xfs_buf_associate_memory(bp, val, cnt)
336 #define XFS_BUF_ADDR(bp) ((bp)->b_bn)
337 #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno))
338 #define XFS_BUF_OFFSET(bp) ((bp)->b_file_offset)
339 #define XFS_BUF_SET_OFFSET(bp, off) ((bp)->b_file_offset = (off))
340 #define XFS_BUF_COUNT(bp) ((bp)->b_count_desired)
341 #define XFS_BUF_SET_COUNT(bp, cnt) ((bp)->b_count_desired = (cnt))
342 #define XFS_BUF_SIZE(bp) ((bp)->b_buffer_length)
343 #define XFS_BUF_SET_SIZE(bp, cnt) ((bp)->b_buffer_length = (cnt))
344
345 #define XFS_BUF_SET_VTYPE_REF(bp, type, ref) do { } while (0)
346 #define XFS_BUF_SET_VTYPE(bp, type) do { } while (0)
347 #define XFS_BUF_SET_REF(bp, ref) do { } while (0)
348
349 #define XFS_BUF_ISPINNED(bp) xfs_buf_ispin(bp)
350
351 #define XFS_BUF_VALUSEMA(bp) xfs_buf_lock_value(bp)
352 #define XFS_BUF_CPSEMA(bp) (xfs_buf_cond_lock(bp) == 0)
353 #define XFS_BUF_VSEMA(bp) xfs_buf_unlock(bp)
354 #define XFS_BUF_PSEMA(bp,x) xfs_buf_lock(bp)
355 #define XFS_BUF_V_IODONESEMA(bp) up(&bp->b_iodonesema);
356
357 #define XFS_BUF_SET_TARGET(bp, target) ((bp)->b_target = (target))
358 #define XFS_BUF_TARGET(bp) ((bp)->b_target)
359 #define XFS_BUFTARG_NAME(target) xfs_buf_target_name(target)
360
361 static inline int xfs_bawrite(void *mp, xfs_buf_t *bp)
362 {
363 bp->b_fspriv3 = mp;
364 bp->b_strat = xfs_bdstrat_cb;
365 xfs_buf_delwri_dequeue(bp);
366 return xfs_buf_iostart(bp, XBF_WRITE | XBF_ASYNC | _XBF_RUN_QUEUES);
367 }
368
369 static inline void xfs_buf_relse(xfs_buf_t *bp)
370 {
371 if (!bp->b_relse)
372 xfs_buf_unlock(bp);
373 xfs_buf_rele(bp);
374 }
375
376 #define xfs_bpin(bp) xfs_buf_pin(bp)
377 #define xfs_bunpin(bp) xfs_buf_unpin(bp)
378
379 #define xfs_buftrace(id, bp) \
380 xfs_buf_trace(bp, id, NULL, (void *)__builtin_return_address(0))
381
382 #define xfs_biodone(bp) xfs_buf_ioend(bp, 0)
383
384 #define xfs_biomove(bp, off, len, data, rw) \
385 xfs_buf_iomove((bp), (off), (len), (data), \
386 ((rw) == XFS_B_WRITE) ? XBRW_WRITE : XBRW_READ)
387
388 #define xfs_biozero(bp, off, len) \
389 xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
390
391
392 static inline int XFS_bwrite(xfs_buf_t *bp)
393 {
394 int iowait = (bp->b_flags & XBF_ASYNC) == 0;
395 int error = 0;
396
397 if (!iowait)
398 bp->b_flags |= _XBF_RUN_QUEUES;
399
400 xfs_buf_delwri_dequeue(bp);
401 xfs_buf_iostrategy(bp);
402 if (iowait) {
403 error = xfs_buf_iowait(bp);
404 xfs_buf_relse(bp);
405 }
406 return error;
407 }
408
409 static inline int xfs_bdwrite(void *mp, xfs_buf_t *bp)
410 {
411 bp->b_strat = xfs_bdstrat_cb;
412 bp->b_fspriv3 = mp;
413 return xfs_buf_iostart(bp, XBF_DELWRI | XBF_ASYNC);
414 }
415
416 #define XFS_bdstrat(bp) xfs_buf_iorequest(bp)
417
418 #define xfs_iowait(bp) xfs_buf_iowait(bp)
419
420 #define xfs_baread(target, rablkno, ralen) \
421 xfs_buf_readahead((target), (rablkno), (ralen), XBF_DONT_BLOCK)
422
423
424 /*
425 * Handling of buftargs.
426 */
427 extern xfs_buftarg_t *xfs_alloc_buftarg(struct block_device *, int);
428 extern void xfs_free_buftarg(xfs_buftarg_t *, int);
429 extern void xfs_wait_buftarg(xfs_buftarg_t *);
430 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
431 extern int xfs_flush_buftarg(xfs_buftarg_t *, int);
432 #ifdef CONFIG_KDB_MODULES
433 extern struct list_head *xfs_get_buftarg_list(void);
434 #endif
435
436 #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
437 #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
438
439 #define xfs_binval(buftarg) xfs_flush_buftarg(buftarg, 1)
440 #define XFS_bflush(buftarg) xfs_flush_buftarg(buftarg, 1)
441
442 #endif /* __XFS_BUF_H__ */
443
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