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  * 4. 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: stable/9/sys/sys/buf.h 251897 2013-06-18 05:21:40Z scottl $
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 
72 typedef unsigned char b_xflags_t;
73 
74 /*
75  * The buffer header describes an I/O operation in the kernel.
76  *
77  * NOTES:
78  *	b_bufsize, b_bcount.  b_bufsize is the allocation size of the
79  *	buffer, either DEV_BSIZE or PAGE_SIZE aligned.  b_bcount is the
80  *	originally requested buffer size and can serve as a bounds check
81  *	against EOF.  For most, but not all uses, b_bcount == b_bufsize.
82  *
83  *	b_dirtyoff, b_dirtyend.  Buffers support piecemeal, unaligned
84  *	ranges of dirty data that need to be written to backing store.
85  *	The range is typically clipped at b_bcount ( not b_bufsize ).
86  *
87  *	b_resid.  Number of bytes remaining in I/O.  After an I/O operation
88  *	completes, b_resid is usually 0 indicating 100% success.
89  *
90  *	All fields are protected by the buffer lock except those marked:
91  *		V - Protected by owning bufobj lock
92  *		Q - Protected by the buf queue lock
93  *		D - Protected by an dependency implementation specific lock
94  */
95 struct buf {
96 	struct bufobj	*b_bufobj;
97 	long		b_bcount;
98 	void		*b_caller1;
99 	caddr_t		b_data;
100 	int		b_error;
101 	uint8_t		b_iocmd;
102 	uint8_t		b_ioflags;
103 	off_t		b_iooffset;
104 	long		b_resid;
105 	void	(*b_iodone)(struct buf *);
106 	daddr_t b_blkno;		/* Underlying physical block number. */
107 	off_t	b_offset;		/* Offset into file. */
108 	TAILQ_ENTRY(buf) b_bobufs;	/* (V) Buffer's associated vnode. */
109 	struct buf	*b_left;	/* (V) splay tree link */
110 	struct buf	*b_right;	/* (V) splay tree link */
111 	uint32_t	b_vflags;	/* (V) BV_* flags */
112 	TAILQ_ENTRY(buf) b_freelist;	/* (Q) Free list position inactive. */
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 	long	b_runningbufspace;	/* when I/O is running, pipelining */
119 	caddr_t	b_kvabase;		/* base kva for buffer */
120 	caddr_t	b_kvaalloc;		/* allocated kva for B_KVAALLOC */
121 	int	b_kvasize;		/* size of kva for buffer */
122 	daddr_t b_lblkno;		/* Logical block number. */
123 	struct	vnode *b_vp;		/* Device vnode. */
124 	int	b_dirtyoff;		/* Offset in buffer of dirty region. */
125 	int	b_dirtyend;		/* Offset of end of dirty region. */
126 	struct	ucred *b_rcred;		/* Read credentials reference. */
127 	struct	ucred *b_wcred;		/* Write credentials reference. */
128 	void	*b_saveaddr;		/* Original b_addr for physio. */
129 	union	pager_info {
130 		int	pg_reqpage;
131 	} b_pager;
132 	union	cluster_info {
133 		TAILQ_HEAD(cluster_list_head, buf) cluster_head;
134 		TAILQ_ENTRY(buf) cluster_entry;
135 	} b_cluster;
136 	struct	vm_page *b_pages[btoc(MAXPHYS)];
137 	int		b_npages;
138 	struct	workhead b_dep;		/* (D) List of filesystem dependencies. */
139 	void	*b_fsprivate1;
140 	void	*b_fsprivate2;
141 	void	*b_fsprivate3;
142 	int	b_pin_count;
143 };
144 
145 #define b_object	b_bufobj->bo_object
146 
147 /*
148  * These flags are kept in b_flags.
149  *
150  * Notes:
151  *
152  *	B_ASYNC		VOP calls on bp's are usually async whether or not
153  *			B_ASYNC is set, but some subsystems, such as NFS, like
154  *			to know what is best for the caller so they can
155  *			optimize the I/O.
156  *
157  *	B_PAGING	Indicates that bp is being used by the paging system or
158  *			some paging system and that the bp is not linked into
159  *			the b_vp's clean/dirty linked lists or ref counts.
160  *			Buffer vp reassignments are illegal in this case.
161  *
162  *	B_CACHE		This may only be set if the buffer is entirely valid.
163  *			The situation where B_DELWRI is set and B_CACHE is
164  *			clear MUST be committed to disk by getblk() so
165  *			B_DELWRI can also be cleared.  See the comments for
166  *			getblk() in kern/vfs_bio.c.  If B_CACHE is clear,
167  *			the caller is expected to clear BIO_ERROR and B_INVAL,
168  *			set BIO_READ, and initiate an I/O.
169  *
170  *			The 'entire buffer' is defined to be the range from
171  *			0 through b_bcount.
172  *
173  *	B_MALLOC	Request that the buffer be allocated from the malloc
174  *			pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned.
175  *
176  *	B_CLUSTEROK	This flag is typically set for B_DELWRI buffers
177  *			by filesystems that allow clustering when the buffer
178  *			is fully dirty and indicates that it may be clustered
179  *			with other adjacent dirty buffers.  Note the clustering
180  *			may not be used with the stage 1 data write under NFS
181  *			but may be used for the commit rpc portion.
182  *
183  *	B_VMIO		Indicates that the buffer is tied into an VM object.
184  *			The buffer's data is always PAGE_SIZE aligned even
185  *			if b_bufsize and b_bcount are not.  ( b_bufsize is
186  *			always at least DEV_BSIZE aligned, though ).
187  *
188  *	B_DIRECT	Hint that we should attempt to completely free
189  *			the pages underlying the buffer.  B_DIRECT is
190  *			sticky until the buffer is released and typically
191  *			only has an effect when B_RELBUF is also set.
192  *
193  */
194 
195 #define	B_AGE		0x00000001	/* Move to age queue when I/O done. */
196 #define	B_NEEDCOMMIT	0x00000002	/* Append-write in progress. */
197 #define	B_ASYNC		0x00000004	/* Start I/O, do not wait. */
198 #define	B_DIRECT	0x00000008	/* direct I/O flag (pls free vmio) */
199 #define	B_DEFERRED	0x00000010	/* Skipped over for cleaning */
200 #define	B_CACHE		0x00000020	/* Bread found us in the cache. */
201 #define	B_VALIDSUSPWRT	0x00000040	/* Valid write during suspension. */
202 #define	B_DELWRI	0x00000080	/* Delay I/O until buffer reused. */
203 #define	B_PERSISTENT	0x00000100	/* Perm. ref'ed while EXT2FS mounted. */
204 #define	B_DONE		0x00000200	/* I/O completed. */
205 #define	B_EINTR		0x00000400	/* I/O was interrupted */
206 #define	B_UNMAPPED	0x00000800	/* KVA is not mapped. */
207 #define	B_KVAALLOC	0x00001000	/* But allocated. */
208 #define	B_INVAL		0x00002000	/* Does not contain valid info. */
209 #define	B_BARRIER	0x00004000	/* Write this and all preceeding first. */
210 #define	B_NOCACHE	0x00008000	/* Do not cache block after use. */
211 #define	B_MALLOC	0x00010000	/* malloced b_data */
212 #define	B_CLUSTEROK	0x00020000	/* Pagein op, so swap() can count it. */
213 #define	B_000400000	0x00040000	/* Available flag. */
214 #define	B_000800000	0x00080000	/* Available flag. */
215 #define	B_00100000	0x00100000	/* Available flag. */
216 #define	B_DIRTY		0x00200000	/* Needs writing later (in EXT2FS). */
217 #define	B_RELBUF	0x00400000	/* Release VMIO buffer. */
218 #define	B_00800000	0x00800000	/* Available flag. */
219 #define	B_NOCOPY	0x01000000	/* Don't copy-on-write this buf. */
220 #define	B_NEEDSGIANT	0x02000000	/* Buffer's vnode needs giant. */
221 #define	B_PAGING	0x04000000	/* volatile paging I/O -- bypass VMIO */
222 #define B_MANAGED	0x08000000	/* Managed by FS. */
223 #define B_RAM		0x10000000	/* Read ahead mark (flag) */
224 #define B_VMIO		0x20000000	/* VMIO flag */
225 #define B_CLUSTER	0x40000000	/* pagein op, so swap() can count it */
226 #define B_REMFREE	0x80000000	/* Delayed bremfree */
227 
228 #define PRINT_BUF_FLAGS "\20\40remfree\37cluster\36vmio\35ram\34managed" \
229 	"\33paging\32needsgiant\31nocopy\30b23\27relbuf\26dirty\25b20" \
230 	"\24b19\23b18\22clusterok\21malloc\20nocache\17b14\16inval" \
231 	"\15b12\14b11\13eintr\12done\11persist\10delwri\7validsuspwrt" \
232 	"\6cache\5deferred\4direct\3async\2needcommit\1age"
233 
234 /*
235  * These flags are kept in b_xflags.
236  */
237 #define	BX_VNDIRTY	0x00000001	/* On vnode dirty list */
238 #define	BX_VNCLEAN	0x00000002	/* On vnode clean list */
239 #define	BX_BKGRDWRITE	0x00000010	/* Do writes in background */
240 #define BX_BKGRDMARKER	0x00000020	/* Mark buffer for splay tree */
241 #define	BX_ALTDATA	0x00000040	/* Holds extended data */
242 
243 #define	PRINT_BUF_XFLAGS "\20\7altdata\6bkgrdmarker\5bkgrdwrite\2clean\1dirty"
244 
245 #define	NOOFFSET	(-1LL)		/* No buffer offset calculated yet */
246 
247 /*
248  * These flags are kept in b_vflags.
249  */
250 #define	BV_SCANNED	0x00000001	/* VOP_FSYNC funcs mark written bufs */
251 #define	BV_BKGRDINPROG	0x00000002	/* Background write in progress */
252 #define	BV_BKGRDWAIT	0x00000004	/* Background write waiting */
253 #define	BV_INFREECNT	0x80000000	/* buf is counted in numfreebufs */
254 
255 #define	PRINT_BUF_VFLAGS "\20\40infreecnt\3bkgrdwait\2bkgrdinprog\1scanned"
256 
257 #ifdef _KERNEL
258 /*
259  * Buffer locking
260  */
261 extern const char *buf_wmesg;		/* Default buffer lock message */
262 #define BUF_WMESG "bufwait"
263 #include <sys/proc.h>			/* XXX for curthread */
264 #include <sys/mutex.h>
265 
266 /*
267  * Initialize a lock.
268  */
269 #define BUF_LOCKINIT(bp)						\
270 	lockinit(&(bp)->b_lock, PRIBIO + 4, buf_wmesg, 0, 0)
271 /*
272  *
273  * Get a lock sleeping non-interruptably until it becomes available.
274  */
275 #define	BUF_LOCK(bp, locktype, interlock)				\
276 	_lockmgr_args(&(bp)->b_lock, (locktype), (interlock),		\
277 	    LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT,		\
278 	    LOCK_FILE, LOCK_LINE)
279 
280 /*
281  * Get a lock sleeping with specified interruptably and timeout.
282  */
283 #define	BUF_TIMELOCK(bp, locktype, interlock, wmesg, catch, timo)	\
284 	_lockmgr_args(&(bp)->b_lock, (locktype) | LK_TIMELOCK,		\
285 	    (interlock), (wmesg), (PRIBIO + 4) | (catch), (timo),	\
286 	    LOCK_FILE, LOCK_LINE)
287 
288 /*
289  * Release a lock. Only the acquiring process may free the lock unless
290  * it has been handed off to biodone.
291  */
292 #define	BUF_UNLOCK(bp) do {						\
293 	KASSERT(((bp)->b_flags & B_REMFREE) == 0,			\
294 	    ("BUF_UNLOCK %p while B_REMFREE is still set.", (bp)));	\
295 									\
296 	(void)_lockmgr_args(&(bp)->b_lock, LK_RELEASE, NULL,		\
297 	    LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT,		\
298 	    LOCK_FILE, LOCK_LINE);					\
299 } while (0)
300 
301 /*
302  * Check if a buffer lock is recursed.
303  */
304 #define	BUF_LOCKRECURSED(bp)						\
305 	lockmgr_recursed(&(bp)->b_lock)
306 
307 /*
308  * Check if a buffer lock is currently held.
309  */
310 #define	BUF_ISLOCKED(bp)						\
311 	lockstatus(&(bp)->b_lock)
312 /*
313  * Free a buffer lock.
314  */
315 #define BUF_LOCKFREE(bp) 						\
316 	lockdestroy(&(bp)->b_lock)
317 
318 /*
319  * Print informations on a buffer lock.
320  */
321 #define BUF_LOCKPRINTINFO(bp) 						\
322 	lockmgr_printinfo(&(bp)->b_lock)
323 
324 /*
325  * Buffer lock assertions.
326  */
327 #if defined(INVARIANTS) && defined(INVARIANT_SUPPORT)
328 #define	BUF_ASSERT_LOCKED(bp)						\
329 	_lockmgr_assert(&(bp)->b_lock, KA_LOCKED, LOCK_FILE, LOCK_LINE)
330 #define	BUF_ASSERT_SLOCKED(bp)						\
331 	_lockmgr_assert(&(bp)->b_lock, KA_SLOCKED, LOCK_FILE, LOCK_LINE)
332 #define	BUF_ASSERT_XLOCKED(bp)						\
333 	_lockmgr_assert(&(bp)->b_lock, KA_XLOCKED, LOCK_FILE, LOCK_LINE)
334 #define	BUF_ASSERT_UNLOCKED(bp)						\
335 	_lockmgr_assert(&(bp)->b_lock, KA_UNLOCKED, LOCK_FILE, LOCK_LINE)
336 #define	BUF_ASSERT_HELD(bp)
337 #define	BUF_ASSERT_UNHELD(bp)
338 #else
339 #define	BUF_ASSERT_LOCKED(bp)
340 #define	BUF_ASSERT_SLOCKED(bp)
341 #define	BUF_ASSERT_XLOCKED(bp)
342 #define	BUF_ASSERT_UNLOCKED(bp)
343 #define	BUF_ASSERT_HELD(bp)
344 #define	BUF_ASSERT_UNHELD(bp)
345 #endif
346 
347 #ifdef _SYS_PROC_H_	/* Avoid #include <sys/proc.h> pollution */
348 /*
349  * When initiating asynchronous I/O, change ownership of the lock to the
350  * kernel. Once done, the lock may legally released by biodone. The
351  * original owning process can no longer acquire it recursively, but must
352  * wait until the I/O is completed and the lock has been freed by biodone.
353  */
354 #define	BUF_KERNPROC(bp)						\
355 	_lockmgr_disown(&(bp)->b_lock, LOCK_FILE, LOCK_LINE)
356 #endif
357 
358 /*
359  * Find out if the lock has waiters or not.
360  */
361 #define	BUF_LOCKWAITERS(bp)						\
362 	lockmgr_waiters(&(bp)->b_lock)
363 
364 #endif /* _KERNEL */
365 
366 struct buf_queue_head {
367 	TAILQ_HEAD(buf_queue, buf) queue;
368 	daddr_t last_pblkno;
369 	struct	buf *insert_point;
370 	struct	buf *switch_point;
371 };
372 
373 /*
374  * This structure describes a clustered I/O.  It is stored in the b_saveaddr
375  * field of the buffer on which I/O is done.  At I/O completion, cluster
376  * callback uses the structure to parcel I/O's to individual buffers, and
377  * then free's this structure.
378  */
379 struct cluster_save {
380 	long	bs_bcount;		/* Saved b_bcount. */
381 	long	bs_bufsize;		/* Saved b_bufsize. */
382 	void	*bs_saveaddr;		/* Saved b_addr. */
383 	int	bs_nchildren;		/* Number of associated buffers. */
384 	struct buf **bs_children;	/* List of associated buffers. */
385 };
386 
387 #ifdef _KERNEL
388 
389 static __inline int
bwrite(struct buf * bp)390 bwrite(struct buf *bp)
391 {
392 
393 	KASSERT(bp->b_bufobj != NULL, ("bwrite: no bufobj bp=%p", bp));
394 	KASSERT(bp->b_bufobj->bo_ops != NULL, ("bwrite: no bo_ops bp=%p", bp));
395 	KASSERT(bp->b_bufobj->bo_ops->bop_write != NULL,
396 	    ("bwrite: no bop_write bp=%p", bp));
397 	return (BO_WRITE(bp->b_bufobj, bp));
398 }
399 
400 static __inline void
bstrategy(struct buf * bp)401 bstrategy(struct buf *bp)
402 {
403 
404 	KASSERT(bp->b_bufobj != NULL, ("bstrategy: no bufobj bp=%p", bp));
405 	KASSERT(bp->b_bufobj->bo_ops != NULL,
406 	    ("bstrategy: no bo_ops bp=%p", bp));
407 	KASSERT(bp->b_bufobj->bo_ops->bop_strategy != NULL,
408 	    ("bstrategy: no bop_strategy bp=%p", bp));
409 	BO_STRATEGY(bp->b_bufobj, bp);
410 }
411 
412 static __inline void
buf_start(struct buf * bp)413 buf_start(struct buf *bp)
414 {
415 	if (bioops.io_start)
416 		(*bioops.io_start)(bp);
417 }
418 
419 static __inline void
buf_complete(struct buf * bp)420 buf_complete(struct buf *bp)
421 {
422 	if (bioops.io_complete)
423 		(*bioops.io_complete)(bp);
424 }
425 
426 static __inline void
buf_deallocate(struct buf * bp)427 buf_deallocate(struct buf *bp)
428 {
429 	if (bioops.io_deallocate)
430 		(*bioops.io_deallocate)(bp);
431 	BUF_LOCKFREE(bp);
432 }
433 
434 static __inline int
buf_countdeps(struct buf * bp,int i)435 buf_countdeps(struct buf *bp, int i)
436 {
437 	if (bioops.io_countdeps)
438 		return ((*bioops.io_countdeps)(bp, i));
439 	else
440 		return (0);
441 }
442 
443 #endif /* _KERNEL */
444 
445 /*
446  * Zero out the buffer's data area.
447  */
448 #define	clrbuf(bp) {							\
449 	bzero((bp)->b_data, (u_int)(bp)->b_bcount);			\
450 	(bp)->b_resid = 0;						\
451 }
452 
453 /*
454  * Flags for getblk's last parameter.
455  */
456 #define	GB_LOCK_NOWAIT	0x0001		/* Fail if we block on a buf lock. */
457 #define	GB_NOCREAT	0x0002		/* Don't create a buf if not found. */
458 #define	GB_NOWAIT_BD	0x0004		/* Do not wait for bufdaemon. */
459 #define	GB_UNMAPPED	0x0008		/* Do not mmap buffer pages. */
460 #define	GB_KVAALLOC	0x0010		/* But allocate KVA. */
461 
462 #ifdef _KERNEL
463 extern int	nbuf;			/* The number of buffer headers */
464 extern long	maxswzone;		/* Max KVA for swap structures */
465 extern long	maxbcache;		/* Max KVA for buffer cache */
466 extern long	runningbufspace;
467 extern long	hibufspace;
468 extern int	dirtybufthresh;
469 extern int	bdwriteskip;
470 extern int	dirtybufferflushes;
471 extern int	altbufferflushes;
472 extern int      buf_maxio;              /* nominal maximum I/O for buffer */
473 extern struct	buf *buf;		/* The buffer headers. */
474 extern char	*buffers;		/* The buffer contents. */
475 extern int	bufpages;		/* Number of memory pages in the buffer pool. */
476 extern struct	buf *swbuf;		/* Swap I/O buffer headers. */
477 extern int	nswbuf;			/* Number of swap I/O buffer headers. */
478 extern int	cluster_pbuf_freecnt;	/* Number of pbufs for clusters */
479 extern int	vnode_pbuf_freecnt;	/* Number of pbufs for vnode pager */
480 extern caddr_t	unmapped_buf;
481 
482 void	runningbufwakeup(struct buf *);
483 void	waitrunningbufspace(void);
484 caddr_t	kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est);
485 void	bufinit(void);
486 void	bdata2bio(struct buf *bp, struct bio *bip);
487 void	bwillwrite(void);
488 int	buf_dirty_count_severe(void);
489 void	bremfree(struct buf *);
490 void	bremfreef(struct buf *);	/* XXX Force bremfree, only for nfs. */
491 int	bread(struct vnode *, daddr_t, int, struct ucred *, struct buf **);
492 int     bread_gb(struct vnode *, daddr_t, int, struct ucred *,
493 	    int gbflags, struct buf **);
494 void	breada(struct vnode *, daddr_t *, int *, int, struct ucred *);
495 int	breadn(struct vnode *, daddr_t, int, daddr_t *, int *, int,
496 	    struct ucred *, struct buf **);
497 int	breadn_flags(struct vnode *, daddr_t, int, daddr_t *, int *, int,
498 	    struct ucred *, int, struct buf **);
499 void	bdwrite(struct buf *);
500 void	bawrite(struct buf *);
501 void	babarrierwrite(struct buf *);
502 int	bbarrierwrite(struct buf *);
503 void	bdirty(struct buf *);
504 void	bundirty(struct buf *);
505 void	bufstrategy(struct bufobj *, struct buf *);
506 void	brelse(struct buf *);
507 void	bqrelse(struct buf *);
508 int	vfs_bio_awrite(struct buf *);
509 struct buf *     getpbuf(int *);
510 struct buf *incore(struct bufobj *, daddr_t);
511 struct buf *gbincore(struct bufobj *, daddr_t);
512 struct buf *getblk(struct vnode *, daddr_t, int, int, int, int);
513 struct buf *geteblk(int, int);
514 int	bufwait(struct buf *);
515 int	bufwrite(struct buf *);
516 void	bufdone(struct buf *);
517 void	bufdone_finish(struct buf *);
518 void	bd_speedup(void);
519 
520 int	cluster_read(struct vnode *, u_quad_t, daddr_t, long,
521 	    struct ucred *, long, int, struct buf **);
522 int	cluster_wbuild(struct vnode *, long, daddr_t, int);
523 void	cluster_write(struct vnode *, struct buf *, u_quad_t, int);
524 int	cluster_read_gb(struct vnode *, u_quad_t, daddr_t, long,
525 	    struct ucred *, long, int, int, struct buf **);
526 int	cluster_wbuild_gb(struct vnode *, long, daddr_t, int, int);
527 void	cluster_write_gb(struct vnode *, struct buf *, u_quad_t, int, int);
528 void	vfs_bio_bzero_buf(struct buf *bp, int base, int size);
529 void	vfs_bio_set_valid(struct buf *, int base, int size);
530 void	vfs_bio_clrbuf(struct buf *);
531 void	vfs_busy_pages(struct buf *, int clear_modify);
532 void	vfs_unbusy_pages(struct buf *);
533 int	vmapbuf(struct buf *, int);
534 void	vunmapbuf(struct buf *);
535 void	relpbuf(struct buf *, int *);
536 void	brelvp(struct buf *);
537 void	bgetvp(struct vnode *, struct buf *);
538 void	pbgetbo(struct bufobj *bo, struct buf *bp);
539 void	pbgetvp(struct vnode *, struct buf *);
540 void	pbrelbo(struct buf *);
541 void	pbrelvp(struct buf *);
542 int	allocbuf(struct buf *bp, int size);
543 void	reassignbuf(struct buf *);
544 struct	buf *trypbuf(int *);
545 void	bwait(struct buf *, u_char, const char *);
546 void	bdone(struct buf *);
547 void	bpin(struct buf *);
548 void	bunpin(struct buf *);
549 void 	bunpin_wait(struct buf *);
550 
551 #endif /* _KERNEL */
552 
553 #endif /* !_SYS_BUF_H_ */
554