xref: /freebsd/sys/sys/buf.h (revision 38069501)
1 /*-
2  * Copyright (c) 1982, 1986, 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)buf.h	8.9 (Berkeley) 3/30/95
35  * $FreeBSD$
36  */
37 
38 #ifndef _SYS_BUF_H_
39 #define	_SYS_BUF_H_
40 
41 #include <sys/bufobj.h>
42 #include <sys/queue.h>
43 #include <sys/lock.h>
44 #include <sys/lockmgr.h>
45 
46 struct bio;
47 struct buf;
48 struct bufobj;
49 struct mount;
50 struct vnode;
51 struct uio;
52 
53 /*
54  * To avoid including <ufs/ffs/softdep.h>
55  */
56 LIST_HEAD(workhead, worklist);
57 /*
58  * These are currently used only by the soft dependency code, hence
59  * are stored once in a global variable. If other subsystems wanted
60  * to use these hooks, a pointer to a set of bio_ops could be added
61  * to each buffer.
62  */
63 extern struct bio_ops {
64 	void	(*io_start)(struct buf *);
65 	void	(*io_complete)(struct buf *);
66 	void	(*io_deallocate)(struct buf *);
67 	int	(*io_countdeps)(struct buf *, int);
68 } bioops;
69 
70 struct vm_object;
71 struct vm_page;
72 
73 typedef uint32_t b_xflags_t;
74 
75 /*
76  * The buffer header describes an I/O operation in the kernel.
77  *
78  * NOTES:
79  *	b_bufsize, b_bcount.  b_bufsize is the allocation size of the
80  *	buffer, either DEV_BSIZE or PAGE_SIZE aligned.  b_bcount is the
81  *	originally requested buffer size and can serve as a bounds check
82  *	against EOF.  For most, but not all uses, b_bcount == b_bufsize.
83  *
84  *	b_dirtyoff, b_dirtyend.  Buffers support piecemeal, unaligned
85  *	ranges of dirty data that need to be written to backing store.
86  *	The range is typically clipped at b_bcount ( not b_bufsize ).
87  *
88  *	b_resid.  Number of bytes remaining in I/O.  After an I/O operation
89  *	completes, b_resid is usually 0 indicating 100% success.
90  *
91  *	All fields are protected by the buffer lock except those marked:
92  *		V - Protected by owning bufobj lock
93  *		Q - Protected by the buf queue lock
94  *		D - Protected by an dependency implementation specific lock
95  */
96 struct buf {
97 	struct bufobj	*b_bufobj;
98 	long		b_bcount;
99 	void		*b_caller1;
100 	caddr_t		b_data;
101 	int		b_error;
102 	uint16_t	b_iocmd;	/* BIO_* bio_cmd from bio.h */
103 	uint16_t	b_ioflags;	/* BIO_* bio_flags from bio.h */
104 	off_t		b_iooffset;
105 	long		b_resid;
106 	void	(*b_iodone)(struct buf *);
107 	void	(*b_ckhashcalc)(struct buf *);
108 	uint64_t	b_ckhash;	/* B_CKHASH requested check-hash */
109 	daddr_t b_blkno;		/* Underlying physical block number. */
110 	off_t	b_offset;		/* Offset into file. */
111 	TAILQ_ENTRY(buf) b_bobufs;	/* (V) Buffer's associated vnode. */
112 	uint32_t	b_vflags;	/* (V) BV_* flags */
113 	unsigned short b_qindex;	/* (Q) buffer queue index */
114 	uint32_t	b_flags;	/* B_* flags. */
115 	b_xflags_t b_xflags;		/* extra flags */
116 	struct lock b_lock;		/* Buffer lock */
117 	long	b_bufsize;		/* Allocated buffer size. */
118 	int	b_runningbufspace;	/* when I/O is running, pipelining */
119 	int	b_kvasize;		/* size of kva for buffer */
120 	int	b_dirtyoff;		/* Offset in buffer of dirty region. */
121 	int	b_dirtyend;		/* Offset of end of dirty region. */
122 	caddr_t	b_kvabase;		/* base kva for buffer */
123 	daddr_t b_lblkno;		/* Logical block number. */
124 	struct	vnode *b_vp;		/* Device vnode. */
125 	struct	ucred *b_rcred;		/* Read credentials reference. */
126 	struct	ucred *b_wcred;		/* Write credentials reference. */
127 	union {
128 		TAILQ_ENTRY(buf) b_freelist; /* (Q) */
129 		struct {
130 			void	(*b_pgiodone)(void *, vm_page_t *, int, int);
131 			int	b_pgbefore;
132 			int	b_pgafter;
133 		};
134 	};
135 	union	cluster_info {
136 		TAILQ_HEAD(cluster_list_head, buf) cluster_head;
137 		TAILQ_ENTRY(buf) cluster_entry;
138 	} b_cluster;
139 	struct	vm_page *b_pages[btoc(MAXPHYS)];
140 	int		b_npages;
141 	struct	workhead b_dep;		/* (D) List of filesystem dependencies. */
142 	void	*b_fsprivate1;
143 	void	*b_fsprivate2;
144 	void	*b_fsprivate3;
145 
146 #if defined(FULL_BUF_TRACKING)
147 #define BUF_TRACKING_SIZE	32
148 #define BUF_TRACKING_ENTRY(x)	((x) & (BUF_TRACKING_SIZE - 1))
149 	const char	*b_io_tracking[BUF_TRACKING_SIZE];
150 	uint32_t	b_io_tcnt;
151 #elif defined(BUF_TRACKING)
152 	const char	*b_io_tracking;
153 #endif
154 };
155 
156 #define b_object	b_bufobj->bo_object
157 
158 /*
159  * These flags are kept in b_flags.
160  *
161  * Notes:
162  *
163  *	B_ASYNC		VOP calls on bp's are usually async whether or not
164  *			B_ASYNC is set, but some subsystems, such as NFS, like
165  *			to know what is best for the caller so they can
166  *			optimize the I/O.
167  *
168  *	B_PAGING	Indicates that bp is being used by the paging system or
169  *			some paging system and that the bp is not linked into
170  *			the b_vp's clean/dirty linked lists or ref counts.
171  *			Buffer vp reassignments are illegal in this case.
172  *
173  *	B_CACHE		This may only be set if the buffer is entirely valid.
174  *			The situation where B_DELWRI is set and B_CACHE is
175  *			clear MUST be committed to disk by getblk() so
176  *			B_DELWRI can also be cleared.  See the comments for
177  *			getblk() in kern/vfs_bio.c.  If B_CACHE is clear,
178  *			the caller is expected to clear BIO_ERROR and B_INVAL,
179  *			set BIO_READ, and initiate an I/O.
180  *
181  *			The 'entire buffer' is defined to be the range from
182  *			0 through b_bcount.
183  *
184  *	B_MALLOC	Request that the buffer be allocated from the malloc
185  *			pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned.
186  *
187  *	B_CLUSTEROK	This flag is typically set for B_DELWRI buffers
188  *			by filesystems that allow clustering when the buffer
189  *			is fully dirty and indicates that it may be clustered
190  *			with other adjacent dirty buffers.  Note the clustering
191  *			may not be used with the stage 1 data write under NFS
192  *			but may be used for the commit rpc portion.
193  *
194  *	B_VMIO		Indicates that the buffer is tied into an VM object.
195  *			The buffer's data is always PAGE_SIZE aligned even
196  *			if b_bufsize and b_bcount are not.  ( b_bufsize is
197  *			always at least DEV_BSIZE aligned, though ).
198  *
199  *	B_DIRECT	Hint that we should attempt to completely free
200  *			the pages underlying the buffer.  B_DIRECT is
201  *			sticky until the buffer is released and typically
202  *			only has an effect when B_RELBUF is also set.
203  *
204  */
205 
206 #define	B_AGE		0x00000001	/* Move to age queue when I/O done. */
207 #define	B_NEEDCOMMIT	0x00000002	/* Append-write in progress. */
208 #define	B_ASYNC		0x00000004	/* Start I/O, do not wait. */
209 #define	B_DIRECT	0x00000008	/* direct I/O flag (pls free vmio) */
210 #define	B_DEFERRED	0x00000010	/* Skipped over for cleaning */
211 #define	B_CACHE		0x00000020	/* Bread found us in the cache. */
212 #define	B_VALIDSUSPWRT	0x00000040	/* Valid write during suspension. */
213 #define	B_DELWRI	0x00000080	/* Delay I/O until buffer reused. */
214 #define	B_CKHASH	0x00000100	/* checksum hash calculated on read */
215 #define	B_DONE		0x00000200	/* I/O completed. */
216 #define	B_EINTR		0x00000400	/* I/O was interrupted */
217 #define	B_NOREUSE	0x00000800	/* Contents not reused once released. */
218 #define	B_00001000	0x00001000	/* Available flag. */
219 #define	B_INVAL		0x00002000	/* Does not contain valid info. */
220 #define	B_BARRIER	0x00004000	/* Write this and all preceding first. */
221 #define	B_NOCACHE	0x00008000	/* Do not cache block after use. */
222 #define	B_MALLOC	0x00010000	/* malloced b_data */
223 #define	B_CLUSTEROK	0x00020000	/* Pagein op, so swap() can count it. */
224 #define	B_00040000	0x00040000	/* Available flag. */
225 #define	B_00080000	0x00080000	/* Available flag. */
226 #define	B_00100000	0x00100000	/* Available flag. */
227 #define	B_00200000	0x00200000	/* Available flag. */
228 #define	B_RELBUF	0x00400000	/* Release VMIO buffer. */
229 #define	B_FS_FLAG1	0x00800000	/* Available flag for FS use. */
230 #define	B_NOCOPY	0x01000000	/* Don't copy-on-write this buf. */
231 #define	B_INFREECNT	0x02000000	/* buf is counted in numfreebufs */
232 #define	B_PAGING	0x04000000	/* volatile paging I/O -- bypass VMIO */
233 #define B_MANAGED	0x08000000	/* Managed by FS. */
234 #define B_RAM		0x10000000	/* Read ahead mark (flag) */
235 #define B_VMIO		0x20000000	/* VMIO flag */
236 #define B_CLUSTER	0x40000000	/* pagein op, so swap() can count it */
237 #define B_REMFREE	0x80000000	/* Delayed bremfree */
238 
239 #define PRINT_BUF_FLAGS "\20\40remfree\37cluster\36vmio\35ram\34managed" \
240 	"\33paging\32infreecnt\31nocopy\30b23\27relbuf\26b21\25b20" \
241 	"\24b19\23b18\22clusterok\21malloc\20nocache\17b14\16inval" \
242 	"\15b12\14noreuse\13eintr\12done\11b8\10delwri" \
243 	"\7validsuspwrt\6cache\5deferred\4direct\3async\2needcommit\1age"
244 
245 /*
246  * These flags are kept in b_xflags.
247  *
248  * BX_FSPRIV reserves a set of eight flags that may be used by individual
249  * filesystems for their own purpose. Their specific definitions are
250  * found in the header files for each filesystem that uses them.
251  */
252 #define	BX_VNDIRTY	0x00000001	/* On vnode dirty list */
253 #define	BX_VNCLEAN	0x00000002	/* On vnode clean list */
254 #define	BX_BKGRDWRITE	0x00000010	/* Do writes in background */
255 #define BX_BKGRDMARKER	0x00000020	/* Mark buffer for splay tree */
256 #define	BX_ALTDATA	0x00000040	/* Holds extended data */
257 #define	BX_FSPRIV	0x00FF0000	/* filesystem-specific flags mask */
258 
259 #define	PRINT_BUF_XFLAGS "\20\7altdata\6bkgrdmarker\5bkgrdwrite\2clean\1dirty"
260 
261 #define	NOOFFSET	(-1LL)		/* No buffer offset calculated yet */
262 
263 /*
264  * These flags are kept in b_vflags.
265  */
266 #define	BV_SCANNED	0x00000001	/* VOP_FSYNC funcs mark written bufs */
267 #define	BV_BKGRDINPROG	0x00000002	/* Background write in progress */
268 #define	BV_BKGRDWAIT	0x00000004	/* Background write waiting */
269 #define	BV_BKGRDERR	0x00000008	/* Error from background write */
270 
271 #define	PRINT_BUF_VFLAGS "\20\4bkgrderr\3bkgrdwait\2bkgrdinprog\1scanned"
272 
273 #ifdef _KERNEL
274 /*
275  * Buffer locking
276  */
277 extern const char *buf_wmesg;		/* Default buffer lock message */
278 #define BUF_WMESG "bufwait"
279 #include <sys/proc.h>			/* XXX for curthread */
280 #include <sys/mutex.h>
281 
282 /*
283  * Initialize a lock.
284  */
285 #define BUF_LOCKINIT(bp)						\
286 	lockinit(&(bp)->b_lock, PRIBIO + 4, buf_wmesg, 0, 0)
287 /*
288  *
289  * Get a lock sleeping non-interruptably until it becomes available.
290  */
291 #define	BUF_LOCK(bp, locktype, interlock)				\
292 	_lockmgr_args_rw(&(bp)->b_lock, (locktype), (interlock),	\
293 	    LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT,		\
294 	    LOCK_FILE, LOCK_LINE)
295 
296 /*
297  * Get a lock sleeping with specified interruptably and timeout.
298  */
299 #define	BUF_TIMELOCK(bp, locktype, interlock, wmesg, catch, timo)	\
300 	_lockmgr_args_rw(&(bp)->b_lock, (locktype) | LK_TIMELOCK,	\
301 	    (interlock), (wmesg), (PRIBIO + 4) | (catch), (timo),	\
302 	    LOCK_FILE, LOCK_LINE)
303 
304 /*
305  * Release a lock. Only the acquiring process may free the lock unless
306  * it has been handed off to biodone.
307  */
308 #define	BUF_UNLOCK(bp) do {						\
309 	KASSERT(((bp)->b_flags & B_REMFREE) == 0,			\
310 	    ("BUF_UNLOCK %p while B_REMFREE is still set.", (bp)));	\
311 									\
312 	(void)_lockmgr_args(&(bp)->b_lock, LK_RELEASE, NULL,		\
313 	    LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT,		\
314 	    LOCK_FILE, LOCK_LINE);					\
315 } while (0)
316 
317 /*
318  * Check if a buffer lock is recursed.
319  */
320 #define	BUF_LOCKRECURSED(bp)						\
321 	lockmgr_recursed(&(bp)->b_lock)
322 
323 /*
324  * Check if a buffer lock is currently held.
325  */
326 #define	BUF_ISLOCKED(bp)						\
327 	lockstatus(&(bp)->b_lock)
328 /*
329  * Free a buffer lock.
330  */
331 #define BUF_LOCKFREE(bp) 						\
332 	lockdestroy(&(bp)->b_lock)
333 
334 /*
335  * Print informations on a buffer lock.
336  */
337 #define BUF_LOCKPRINTINFO(bp) 						\
338 	lockmgr_printinfo(&(bp)->b_lock)
339 
340 /*
341  * Buffer lock assertions.
342  */
343 #if defined(INVARIANTS) && defined(INVARIANT_SUPPORT)
344 #define	BUF_ASSERT_LOCKED(bp)						\
345 	_lockmgr_assert(&(bp)->b_lock, KA_LOCKED, LOCK_FILE, LOCK_LINE)
346 #define	BUF_ASSERT_SLOCKED(bp)						\
347 	_lockmgr_assert(&(bp)->b_lock, KA_SLOCKED, LOCK_FILE, LOCK_LINE)
348 #define	BUF_ASSERT_XLOCKED(bp)						\
349 	_lockmgr_assert(&(bp)->b_lock, KA_XLOCKED, LOCK_FILE, LOCK_LINE)
350 #define	BUF_ASSERT_UNLOCKED(bp)						\
351 	_lockmgr_assert(&(bp)->b_lock, KA_UNLOCKED, LOCK_FILE, LOCK_LINE)
352 #define	BUF_ASSERT_HELD(bp)
353 #define	BUF_ASSERT_UNHELD(bp)
354 #else
355 #define	BUF_ASSERT_LOCKED(bp)
356 #define	BUF_ASSERT_SLOCKED(bp)
357 #define	BUF_ASSERT_XLOCKED(bp)
358 #define	BUF_ASSERT_UNLOCKED(bp)
359 #define	BUF_ASSERT_HELD(bp)
360 #define	BUF_ASSERT_UNHELD(bp)
361 #endif
362 
363 #ifdef _SYS_PROC_H_	/* Avoid #include <sys/proc.h> pollution */
364 /*
365  * When initiating asynchronous I/O, change ownership of the lock to the
366  * kernel. Once done, the lock may legally released by biodone. The
367  * original owning process can no longer acquire it recursively, but must
368  * wait until the I/O is completed and the lock has been freed by biodone.
369  */
370 #define	BUF_KERNPROC(bp)						\
371 	_lockmgr_disown(&(bp)->b_lock, LOCK_FILE, LOCK_LINE)
372 #endif
373 
374 #endif /* _KERNEL */
375 
376 struct buf_queue_head {
377 	TAILQ_HEAD(buf_queue, buf) queue;
378 	daddr_t last_pblkno;
379 	struct	buf *insert_point;
380 	struct	buf *switch_point;
381 };
382 
383 /*
384  * This structure describes a clustered I/O.
385  */
386 struct cluster_save {
387 	long	bs_bcount;		/* Saved b_bcount. */
388 	long	bs_bufsize;		/* Saved b_bufsize. */
389 	int	bs_nchildren;		/* Number of associated buffers. */
390 	struct buf **bs_children;	/* List of associated buffers. */
391 };
392 
393 #ifdef _KERNEL
394 
395 static __inline int
396 bwrite(struct buf *bp)
397 {
398 
399 	KASSERT(bp->b_bufobj != NULL, ("bwrite: no bufobj bp=%p", bp));
400 	KASSERT(bp->b_bufobj->bo_ops != NULL, ("bwrite: no bo_ops bp=%p", bp));
401 	KASSERT(bp->b_bufobj->bo_ops->bop_write != NULL,
402 	    ("bwrite: no bop_write bp=%p", bp));
403 	return (BO_WRITE(bp->b_bufobj, bp));
404 }
405 
406 static __inline void
407 bstrategy(struct buf *bp)
408 {
409 
410 	KASSERT(bp->b_bufobj != NULL, ("bstrategy: no bufobj bp=%p", bp));
411 	KASSERT(bp->b_bufobj->bo_ops != NULL,
412 	    ("bstrategy: no bo_ops bp=%p", bp));
413 	KASSERT(bp->b_bufobj->bo_ops->bop_strategy != NULL,
414 	    ("bstrategy: no bop_strategy bp=%p", bp));
415 	BO_STRATEGY(bp->b_bufobj, bp);
416 }
417 
418 static __inline void
419 buf_start(struct buf *bp)
420 {
421 	if (bioops.io_start)
422 		(*bioops.io_start)(bp);
423 }
424 
425 static __inline void
426 buf_complete(struct buf *bp)
427 {
428 	if (bioops.io_complete)
429 		(*bioops.io_complete)(bp);
430 }
431 
432 static __inline void
433 buf_deallocate(struct buf *bp)
434 {
435 	if (bioops.io_deallocate)
436 		(*bioops.io_deallocate)(bp);
437 }
438 
439 static __inline int
440 buf_countdeps(struct buf *bp, int i)
441 {
442 	if (bioops.io_countdeps)
443 		return ((*bioops.io_countdeps)(bp, i));
444 	else
445 		return (0);
446 }
447 
448 static __inline void
449 buf_track(struct buf *bp, const char *location)
450 {
451 
452 #if defined(FULL_BUF_TRACKING)
453 	bp->b_io_tracking[BUF_TRACKING_ENTRY(bp->b_io_tcnt++)] = location;
454 #elif defined(BUF_TRACKING)
455 	bp->b_io_tracking = location;
456 #endif
457 }
458 
459 #endif /* _KERNEL */
460 
461 /*
462  * Zero out the buffer's data area.
463  */
464 #define	clrbuf(bp) {							\
465 	bzero((bp)->b_data, (u_int)(bp)->b_bcount);			\
466 	(bp)->b_resid = 0;						\
467 }
468 
469 /*
470  * Flags for getblk's last parameter.
471  */
472 #define	GB_LOCK_NOWAIT	0x0001		/* Fail if we block on a buf lock. */
473 #define	GB_NOCREAT	0x0002		/* Don't create a buf if not found. */
474 #define	GB_NOWAIT_BD	0x0004		/* Do not wait for bufdaemon. */
475 #define	GB_UNMAPPED	0x0008		/* Do not mmap buffer pages. */
476 #define	GB_KVAALLOC	0x0010		/* But allocate KVA. */
477 #define	GB_CKHASH	0x0020		/* If reading, calc checksum hash */
478 
479 #ifdef _KERNEL
480 extern int	nbuf;			/* The number of buffer headers */
481 extern long	maxswzone;		/* Max KVA for swap structures */
482 extern long	maxbcache;		/* Max KVA for buffer cache */
483 extern int	maxbcachebuf;		/* Max buffer cache block size */
484 extern long	runningbufspace;
485 extern long	hibufspace;
486 extern int	dirtybufthresh;
487 extern int	bdwriteskip;
488 extern int	dirtybufferflushes;
489 extern int	altbufferflushes;
490 extern int	nswbuf;			/* Number of swap I/O buffer headers. */
491 extern int	cluster_pbuf_freecnt;	/* Number of pbufs for clusters */
492 extern int	vnode_pbuf_freecnt;	/* Number of pbufs for vnode pager */
493 extern int	vnode_async_pbuf_freecnt; /* Number of pbufs for vnode pager,
494 					     asynchronous reads */
495 extern caddr_t	unmapped_buf;	/* Data address for unmapped buffers. */
496 
497 static inline int
498 buf_mapped(struct buf *bp)
499 {
500 
501 	return (bp->b_data != unmapped_buf);
502 }
503 
504 void	runningbufwakeup(struct buf *);
505 void	waitrunningbufspace(void);
506 caddr_t	kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est);
507 void	bufinit(void);
508 void	bufshutdown(int);
509 void	bdata2bio(struct buf *bp, struct bio *bip);
510 void	bwillwrite(void);
511 int	buf_dirty_count_severe(void);
512 void	bremfree(struct buf *);
513 void	bremfreef(struct buf *);	/* XXX Force bremfree, only for nfs. */
514 #define bread(vp, blkno, size, cred, bpp) \
515 	    breadn_flags(vp, blkno, size, NULL, NULL, 0, cred, 0, NULL, bpp)
516 #define bread_gb(vp, blkno, size, cred, gbflags, bpp) \
517 	    breadn_flags(vp, blkno, size, NULL, NULL, 0, cred, \
518 		gbflags, NULL, bpp)
519 #define breadn(vp, blkno, size, rablkno, rabsize, cnt, cred, bpp) \
520 	    breadn_flags(vp, blkno, size, rablkno, rabsize, cnt, cred, \
521 		0, NULL, bpp)
522 int	breadn_flags(struct vnode *, daddr_t, int, daddr_t *, int *, int,
523 	    struct ucred *, int, void (*)(struct buf *), struct buf **);
524 void	bdwrite(struct buf *);
525 void	bawrite(struct buf *);
526 void	babarrierwrite(struct buf *);
527 int	bbarrierwrite(struct buf *);
528 void	bdirty(struct buf *);
529 void	bundirty(struct buf *);
530 void	bufstrategy(struct bufobj *, struct buf *);
531 void	brelse(struct buf *);
532 void	bqrelse(struct buf *);
533 int	vfs_bio_awrite(struct buf *);
534 void	vfs_drain_busy_pages(struct buf *bp);
535 struct buf *     getpbuf(int *);
536 struct buf *incore(struct bufobj *, daddr_t);
537 struct buf *gbincore(struct bufobj *, daddr_t);
538 struct buf *getblk(struct vnode *, daddr_t, int, int, int, int);
539 struct buf *geteblk(int, int);
540 int	bufwait(struct buf *);
541 int	bufwrite(struct buf *);
542 void	bufdone(struct buf *);
543 void	bufdone_finish(struct buf *);
544 void	bd_speedup(void);
545 
546 int	cluster_read(struct vnode *, u_quad_t, daddr_t, long,
547 	    struct ucred *, long, int, int, struct buf **);
548 int	cluster_wbuild(struct vnode *, long, daddr_t, int, int);
549 void	cluster_write(struct vnode *, struct buf *, u_quad_t, int, int);
550 void	vfs_bio_brelse(struct buf *bp, int ioflags);
551 void	vfs_bio_bzero_buf(struct buf *bp, int base, int size);
552 void	vfs_bio_clrbuf(struct buf *);
553 void	vfs_bio_set_flags(struct buf *bp, int ioflags);
554 void	vfs_bio_set_valid(struct buf *, int base, int size);
555 void	vfs_busy_pages(struct buf *, int clear_modify);
556 void	vfs_unbusy_pages(struct buf *);
557 int	vmapbuf(struct buf *, int);
558 void	vunmapbuf(struct buf *);
559 void	relpbuf(struct buf *, int *);
560 void	brelvp(struct buf *);
561 void	bgetvp(struct vnode *, struct buf *);
562 void	pbgetbo(struct bufobj *bo, struct buf *bp);
563 void	pbgetvp(struct vnode *, struct buf *);
564 void	pbrelbo(struct buf *);
565 void	pbrelvp(struct buf *);
566 int	allocbuf(struct buf *bp, int size);
567 void	reassignbuf(struct buf *);
568 struct	buf *trypbuf(int *);
569 void	bwait(struct buf *, u_char, const char *);
570 void	bdone(struct buf *);
571 
572 typedef daddr_t (vbg_get_lblkno_t)(struct vnode *, vm_ooffset_t);
573 typedef int (vbg_get_blksize_t)(struct vnode *, daddr_t);
574 int	vfs_bio_getpages(struct vnode *vp, struct vm_page **ma, int count,
575 	    int *rbehind, int *rahead, vbg_get_lblkno_t get_lblkno,
576 	    vbg_get_blksize_t get_blksize);
577 
578 #endif /* _KERNEL */
579 
580 #endif /* !_SYS_BUF_H_ */
581