aboutsummaryrefslogtreecommitdiff
path: root/fs/xfs/linux-2.6/xfs_buf.h
blob: a509f4addc2a10e2677fc1e6b6544358f925c777 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef __XFS_BUF_H__
#define __XFS_BUF_H__

#include <linux/list.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <asm/system.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/uio.h>

/*
 *	Base types
 */

#define XFS_BUF_DADDR_NULL	((xfs_daddr_t) (-1LL))

#define xfs_buf_ctob(pp)	((pp) * PAGE_CACHE_SIZE)
#define xfs_buf_btoc(dd)	(((dd) + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT)
#define xfs_buf_btoct(dd)	((dd) >> PAGE_CACHE_SHIFT)
#define xfs_buf_poff(aa)	((aa) & ~PAGE_CACHE_MASK)

typedef enum {
	XBRW_READ = 1,			/* transfer into target memory */
	XBRW_WRITE = 2,			/* transfer from target memory */
	XBRW_ZERO = 3,			/* Zero target memory */
} xfs_buf_rw_t;

typedef enum {
	XBF_READ = (1 << 0),	/* buffer intended for reading from device */
	XBF_WRITE = (1 << 1),	/* buffer intended for writing to device   */
	XBF_MAPPED = (1 << 2),  /* buffer mapped (b_addr valid)            */
	XBF_ASYNC = (1 << 4),   /* initiator will not wait for completion  */
	XBF_DONE = (1 << 5),    /* all pages in the buffer uptodate	   */
	XBF_DELWRI = (1 << 6),  /* buffer has dirty pages                  */
	XBF_STALE = (1 << 7),	/* buffer has been staled, do not find it  */
	XBF_FS_MANAGED = (1 << 8),  /* filesystem controls freeing memory  */
 	XBF_ORDERED = (1 << 11),    /* use ordered writes		   */
	XBF_READ_AHEAD = (1 << 12), /* asynchronous read-ahead		   */

	/* flags used only as arguments to access routines */
	XBF_LOCK = (1 << 14),       /* lock requested			   */
	XBF_TRYLOCK = (1 << 15),    /* lock requested, but do not wait	   */
	XBF_DONT_BLOCK = (1 << 16), /* do not block in current thread	   */

	/* flags used only internally */
	_XBF_PAGE_CACHE = (1 << 17),/* backed by pagecache		   */
	_XBF_PAGES = (1 << 18),	    /* backed by refcounted pages	   */
	_XBF_RUN_QUEUES = (1 << 19),/* run block device task queue	   */
	_XBF_DELWRI_Q = (1 << 21),   /* buffer on delwri queue		   */

	/*
	 * Special flag for supporting metadata blocks smaller than a FSB.
	 *
	 * In this case we can have multiple xfs_buf_t on a single page and
	 * need to lock out concurrent xfs_buf_t readers as they only
	 * serialise access to the buffer.
	 *
	 * If the FSB size >= PAGE_CACHE_SIZE case, we have no serialisation
	 * between reads of the page. Hence we can have one thread read the
	 * page and modify it, but then race with another thread that thinks
	 * the page is not up-to-date and hence reads it again.
	 *
	 * The result is that the first modifcation to the page is lost.
	 * This sort of AGF/AGI reading race can happen when unlinking inodes
	 * that require truncation and results in the AGI unlinked list
	 * modifications being lost.
	 */
	_XBF_PAGE_LOCKED = (1 << 22),

	/*
	 * If we try a barrier write, but it fails we have to communicate
	 * this to the upper layers.  Unfortunately b_error gets overwritten
	 * when the buffer is re-issued so we have to add another flag to
	 * keep this information.
	 */
	_XFS_BARRIER_FAILED = (1 << 23),
} xfs_buf_flags_t;

#define XFS_BUF_FLAGS \
	{ XBF_READ,		"READ" }, \
	{ XBF_WRITE,		"WRITE" }, \
	{ XBF_MAPPED,		"MAPPED" }, \
	{ XBF_ASYNC,		"ASYNC" }, \
	{ XBF_DONE,		"DONE" }, \
	{ XBF_DELWRI,		"DELWRI" }, \
	{ XBF_STALE,		"STALE" }, \
	{ XBF_FS_MANAGED,	"FS_MANAGED" }, \
	{ XBF_ORDERED,		"ORDERED" }, \
	{ XBF_READ_AHEAD,	"READ_AHEAD" }, \
	{ XBF_LOCK,		"LOCK" },  	/* should never be set */\
	{ XBF_TRYLOCK,		"TRYLOCK" }, 	/* ditto */\
	{ XBF_DONT_BLOCK,	"DONT_BLOCK" },	/* ditto */\
	{ _XBF_PAGE_CACHE,	"PAGE_CACHE" }, \
	{ _XBF_PAGES,		"PAGES" }, \
	{ _XBF_RUN_QUEUES,	"RUN_QUEUES" }, \
	{ _XBF_DELWRI_Q,	"DELWRI_Q" }, \
	{ _XBF_PAGE_LOCKED,	"PAGE_LOCKED" }, \
	{ _XFS_BARRIER_FAILED,	"BARRIER_FAILED" }


typedef enum {
	XBT_FORCE_SLEEP = 0,
	XBT_FORCE_FLUSH = 1,
} xfs_buftarg_flags_t;

typedef struct xfs_bufhash {
	struct list_head	bh_list;
	spinlock_t		bh_lock;
} xfs_bufhash_t;

typedef struct xfs_buftarg {
	dev_t			bt_dev;
	struct block_device	*bt_bdev;
	struct address_space	*bt_mapping;
	unsigned int		bt_bsize;
	unsigned int		bt_sshift;
	size_t			bt_smask;

	/* per device buffer hash table */
	uint			bt_hashmask;
	uint			bt_hashshift;
	xfs_bufhash_t		*bt_hash;

	/* per device delwri queue */
	struct task_struct	*bt_task;
	struct list_head	bt_list;
	struct list_head	bt_delwrite_queue;
	spinlock_t		bt_delwrite_lock;
	unsigned long		bt_flags;
} xfs_buftarg_t;

/*
 *	xfs_buf_t:  Buffer structure for pagecache-based buffers
 *
 * This buffer structure is used by the pagecache buffer management routines
 * to refer to an assembly of pages forming a logical buffer.
 *
 * The buffer structure is used on a temporary basis only, and discarded when
 * released.  The real data storage is recorded in the pagecache. Buffers are
 * hashed to the block device on which the file system resides.
 */

struct xfs_buf;
typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
typedef void (*xfs_buf_relse_t)(struct xfs_buf *);
typedef int (*xfs_buf_bdstrat_t)(struct xfs_buf *);

#define XB_PAGES	2

typedef struct xfs_buf {
	struct semaphore	b_sema;		/* semaphore for lockables */
	unsigned long		b_queuetime;	/* time buffer was queued */
	atomic_t		b_pin_count;	/* pin count */
	wait_queue_head_t	b_waiters;	/* unpin waiters */
	struct list_head	b_list;
	xfs_buf_flags_t		b_flags;	/* status flags */
	struct list_head	b_hash_list;	/* hash table list */
	xfs_bufhash_t		*b_hash;	/* hash table list start */
	xfs_buftarg_t		*b_target;	/* buffer target (device) */
	atomic_t		b_hold;		/* reference count */
	xfs_daddr_t		b_bn;		/* block number for I/O */
	xfs_off_t		b_file_offset;	/* offset in file */
	size_t			b_buffer_length;/* size of buffer in bytes */
	size_t			b_count_desired;/* desired transfer size */
	void			*b_addr;	/* virtual address of buffer */
	struct work_struct	b_iodone_work;
	atomic_t		b_io_remaining;	/* #outstanding I/O requests */
	xfs_buf_iodone_t	b_iodone;	/* I/O completion function */
	xfs_buf_relse_t		b_relse;	/* releasing function */
	xfs_buf_bdstrat_t	b_strat;	/* pre-write function */
	struct completion	b_iowait;	/* queue for I/O waiters */
	void			*b_fspriv;
	void			*b_fspriv2;
	struct xfs_mount	*b_mount;
	unsigned short		b_error;	/* error code on I/O */
	unsigned int		b_page_count;	/* size of page array */
	unsigned int		b_offset;	/* page offset in first page */
	struct page		**b_pages;	/* array of page pointers */
	struct page		*b_page_array[XB_PAGES]; /* inline pages */
#ifdef XFS_BUF_LOCK_TRACKING
	int			b_last_holder;
#endif
} xfs_buf_t;


/* Finding and Reading Buffers */
extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t,
				xfs_buf_flags_t, xfs_buf_t *);
#define xfs_incore(buftarg,blkno,len,lockit) \
	_xfs_buf_find(buftarg, blkno ,len, lockit, NULL)

extern xfs_buf_t *xfs_buf_get(xfs_buftarg_t *, xfs_off_t, size_t,
				xfs_buf_flags_t);
extern xfs_buf_t *xfs_buf_read(xfs_buftarg_t *, xfs_off_t, size_t,
				xfs_buf_flags_t);

extern xfs_buf_t *xfs_buf_get_empty(size_t, xfs_buftarg_t *);
extern xfs_buf_t *xfs_buf_get_noaddr(size_t, xfs_buftarg_t *);
extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t);
extern void xfs_buf_hold(xfs_buf_t *);
extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t,
				xfs_buf_flags_t);

/* Releasing Buffers */
extern void xfs_buf_free(xfs_buf_t *);
extern void xfs_buf_rele(xfs_buf_t *);

/* Locking and Unlocking Buffers */
extern int xfs_buf_cond_lock(xfs_buf_t *);
extern int xfs_buf_lock_value(xfs_buf_t *);
extern void xfs_buf_lock(xfs_buf_t *);
extern void xfs_buf_unlock(xfs_buf_t *);

/* Buffer Read and Write Routines */
extern int xfs_bawrite(void *mp, xfs_buf_t *bp);
extern void xfs_bdwrite(void *mp, xfs_buf_t *bp);
extern void xfs_buf_ioend(xfs_buf_t *,	int);
extern void xfs_buf_ioerror(xfs_buf_t *, int);
extern int xfs_buf_iorequest(xfs_buf_t *);
extern int xfs_buf_iowait(xfs_buf_t *);
extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, xfs_caddr_t,
				xfs_buf_rw_t);

static inline int xfs_buf_iostrategy(xfs_buf_t *bp)
{
	return bp->b_strat ? bp->b_strat(bp) : xfs_buf_iorequest(bp);
}

static inline int xfs_buf_geterror(xfs_buf_t *bp)
{
	return bp ? bp->b_error : ENOMEM;
}

/* Buffer Utility Routines */
extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);

/* Pinning Buffer Storage in Memory */
extern void xfs_buf_pin(xfs_buf_t *);
extern void xfs_buf_unpin(xfs_buf_t *);
extern int xfs_buf_ispin(xfs_buf_t *);

/* Delayed Write Buffer Routines */
extern void xfs_buf_delwri_dequeue(xfs_buf_t *);

/* Buffer Daemon Setup Routines */
extern int xfs_buf_init(void);
extern void xfs_buf_terminate(void);

#define xfs_buf_target_name(target)	\
	({ char __b[BDEVNAME_SIZE]; bdevname((target)->bt_bdev, __b); __b; })


#define XFS_B_ASYNC		XBF_ASYNC
#define XFS_B_DELWRI		XBF_DELWRI
#define XFS_B_READ		XBF_READ
#define XFS_B_WRITE		XBF_WRITE
#define XFS_B_STALE		XBF_STALE

#define XFS_BUF_TRYLOCK		XBF_TRYLOCK
#define XFS_INCORE_TRYLOCK	XBF_TRYLOCK
#define XFS_BUF_LOCK		XBF_LOCK
#define XFS_BUF_MAPPED		XBF_MAPPED

#define BUF_BUSY		XBF_DONT_BLOCK

#define XFS_BUF_BFLAGS(bp)	((bp)->b_flags)
#define XFS_BUF_ZEROFLAGS(bp)	((bp)->b_flags &= \
		~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI|XBF_ORDERED))

#define XFS_BUF_STALE(bp)	((bp)->b_flags |= XFS_B_STALE)
#define XFS_BUF_UNSTALE(bp)	((bp)->b_flags &= ~XFS_B_STALE)
#define XFS_BUF_ISSTALE(bp)	((bp)->b_flags & XFS_B_STALE)
#define XFS_BUF_SUPER_STALE(bp)	do {				\
					XFS_BUF_STALE(bp);	\
					xfs_buf_delwri_dequeue(bp);	\
					XFS_BUF_DONE(bp);	\
				} while (0)

#define XFS_BUF_MANAGE		XBF_FS_MANAGED
#define XFS_BUF_UNMANAGE(bp)	((bp)->b_flags &= ~XBF_FS_MANAGED)

#define XFS_BUF_DELAYWRITE(bp)		((bp)->b_flags |= XBF_DELWRI)
#define XFS_BUF_UNDELAYWRITE(bp)	xfs_buf_delwri_dequeue(bp)
#define XFS_BUF_ISDELAYWRITE(bp)	((bp)->b_flags & XBF_DELWRI)

#define XFS_BUF_ERROR(bp,no)	xfs_buf_ioerror(bp,no)
#define XFS_BUF_GETERROR(bp)	xfs_buf_geterror(bp)
#define XFS_BUF_ISERROR(bp)	(xfs_buf_geterror(bp) ? 1 : 0)

#define XFS_BUF_DONE(bp)	((bp)->b_flags |= XBF_DONE)
#define XFS_BUF_UNDONE(bp)	((bp)->b_flags &= ~XBF_DONE)
#define XFS_BUF_ISDONE(bp)	((bp)->b_flags & XBF_DONE)

#define XFS_BUF_BUSY(bp)	do { } while (0)
#define XFS_BUF_UNBUSY(bp)	do { } while (0)
#define XFS_BUF_ISBUSY(bp)	(1)

#define XFS_BUF_ASYNC(bp)	((bp)->b_flags |= XBF_ASYNC)
#define XFS_BUF_UNASYNC(bp)	((bp)->b_flags &= ~XBF_ASYNC)
#define XFS_BUF_ISASYNC(bp)	((bp)->b_flags & XBF_ASYNC)

#define XFS_BUF_ORDERED(bp)	((bp)->b_flags |= XBF_ORDERED)
#define XFS_BUF_UNORDERED(bp)	((bp)->b_flags &= ~XBF_ORDERED)
#define XFS_BUF_ISORDERED(bp)	((bp)->b_flags & XBF_ORDERED)

#define XFS_BUF_HOLD(bp)	xfs_buf_hold(bp)
#define XFS_BUF_READ(bp)	((bp)->b_flags |= XBF_READ)
#define XFS_BUF_UNREAD(bp)	((bp)->b_flags &= ~XBF_READ)
#define XFS_BUF_ISREAD(bp)	((bp)->b_flags & XBF_READ)

#define XFS_BUF_WRITE(bp)	((bp)->b_flags |= XBF_WRITE)
#define XFS_BUF_UNWRITE(bp)	((bp)->b_flags &= ~XBF_WRITE)
#define XFS_BUF_ISWRITE(bp)	((bp)->b_flags & XBF_WRITE)

#define XFS_BUF_IODONE_FUNC(bp)			((bp)->b_iodone)
#define XFS_BUF_SET_IODONE_FUNC(bp, func)	((bp)->b_iodone = (func))
#define XFS_BUF_CLR_IODONE_FUNC(bp)		((bp)->b_iodone = NULL)
#define XFS_BUF_SET_BDSTRAT_FUNC(bp, func)	((bp)->b_strat = (func))
#define XFS_BUF_CLR_BDSTRAT_FUNC(bp)		((bp)->b_strat = NULL)

#define XFS_BUF_FSPRIVATE(bp, type)		((type)(bp)->b_fspriv)
#define XFS_BUF_SET_FSPRIVATE(bp, val)		((bp)->b_fspriv = (void*)(val))
#define XFS_BUF_FSPRIVATE2(bp, type)		((type)(bp)->b_fspriv2)
#define XFS_BUF_SET_FSPRIVATE2(bp, val)		((bp)->b_fspriv2 = (void*)(val))
#define XFS_BUF_SET_START(bp)			do { } while (0)
#define XFS_BUF_SET_BRELSE_FUNC(bp, func)	((bp)->b_relse = (func))

#define XFS_BUF_PTR(bp)			(xfs_caddr_t)((bp)->b_addr)
#define XFS_BUF_SET_PTR(bp, val, cnt)	xfs_buf_associate_memory(bp, val, cnt)
#define XFS_BUF_ADDR(bp)		((bp)->b_bn)
#define XFS_BUF_SET_ADDR(bp, bno)	((bp)->b_bn = (xfs_daddr_t)(bno))
#define XFS_BUF_OFFSET(bp)		((bp)->b_file_offset)
#define XFS_BUF_SET_OFFSET(bp, off)	((bp)->b_file_offset = (off))
#define XFS_BUF_COUNT(bp)		((bp)->b_count_desired)
#define XFS_BUF_SET_COUNT(bp, cnt)	((bp)->b_count_desired = (cnt))
#define XFS_BUF_SIZE(bp)		((bp)->b_buffer_length)
#define XFS_BUF_SET_SIZE(bp, cnt)	((bp)->b_buffer_length = (cnt))

#define XFS_BUF_SET_VTYPE_REF(bp, type, ref)	do { } while (0)
#define XFS_BUF_SET_VTYPE(bp, type)		do { } while (0)
#define XFS_BUF_SET_REF(bp, ref)		do { } while (0)

#define XFS_BUF_ISPINNED(bp)	xfs_buf_ispin(bp)

#define XFS_BUF_VALUSEMA(bp)	xfs_buf_lock_value(bp)
#define XFS_BUF_CPSEMA(bp)	(xfs_buf_cond_lock(bp) == 0)
#define XFS_BUF_VSEMA(bp)	xfs_buf_unlock(bp)
#define XFS_BUF_PSEMA(bp,x)	xfs_buf_lock(bp)
#define XFS_BUF_FINISH_IOWAIT(bp)	complete(&bp->b_iowait);

#define XFS_BUF_SET_TARGET(bp, target)	((bp)->b_target = (target))
#define XFS_BUF_TARGET(bp)		((bp)->b_target)
#define XFS_BUFTARG_NAME(target)	xfs_buf_target_name(target)

static inline void xfs_buf_relse(xfs_buf_t *bp)
{
	if (!bp->b_relse)
		xfs_buf_unlock(bp);
	xfs_buf_rele(bp);
}

#define xfs_bpin(bp)		xfs_buf_pin(bp)
#define xfs_bunpin(bp)		xfs_buf_unpin(bp)
#define xfs_biodone(bp)		xfs_buf_ioend(bp, 0)

#define xfs_biomove(bp, off, len, data, rw) \
	    xfs_buf_iomove((bp), (off), (len), (data), \
		((rw) == XFS_B_WRITE) ? XBRW_WRITE : XBRW_READ)

#define xfs_biozero(bp, off, len) \
	    xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)


static inline int XFS_bwrite(xfs_buf_t *bp)
{
	int	iowait = (bp->b_flags & XBF_ASYNC) == 0;
	int	error = 0;

	if (!iowait)
		bp->b_flags |= _XBF_RUN_QUEUES;

	xfs_buf_delwri_dequeue(bp);
	xfs_buf_iostrategy(bp);
	if (iowait) {
		error = xfs_buf_iowait(bp);
		xfs_buf_relse(bp);
	}
	return error;
}

#define XFS_bdstrat(bp) xfs_buf_iorequest(bp)

#define xfs_iowait(bp)	xfs_buf_iowait(bp)

#define xfs_baread(target, rablkno, ralen)  \
	xfs_buf_readahead((target), (rablkno), (ralen), XBF_DONT_BLOCK)


/*
 *	Handling of buftargs.
 */
extern xfs_buftarg_t *xfs_alloc_buftarg(struct block_device *, int);
extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
extern void xfs_wait_buftarg(xfs_buftarg_t *);
extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
extern int xfs_flush_buftarg(xfs_buftarg_t *, int);
#ifdef CONFIG_KDB_MODULES
extern struct list_head *xfs_get_buftarg_list(void);
#endif

#define xfs_getsize_buftarg(buftarg)	block_size((buftarg)->bt_bdev)
#define xfs_readonly_buftarg(buftarg)	bdev_read_only((buftarg)->bt_bdev)

#define xfs_binval(buftarg)		xfs_flush_buftarg(buftarg, 1)
#define XFS_bflush(buftarg)		xfs_flush_buftarg(buftarg, 1)

#endif	/* __XFS_BUF_H__ */