xref: /freebsd/sys/sys/buf.h (revision e17f5b1d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)buf.h	8.9 (Berkeley) 3/30/95
37  * $FreeBSD$
38  */
39 
40 #ifndef _SYS_BUF_H_
41 #define	_SYS_BUF_H_
42 
43 #include <sys/bufobj.h>
44 #include <sys/queue.h>
45 #include <sys/lock.h>
46 #include <sys/lockmgr.h>
47 #include <vm/uma.h>
48 
49 struct bio;
50 struct buf;
51 struct bufobj;
52 struct mount;
53 struct vnode;
54 struct uio;
55 
56 /*
57  * To avoid including <ufs/ffs/softdep.h>
58  */
59 LIST_HEAD(workhead, worklist);
60 /*
61  * These are currently used only by the soft dependency code, hence
62  * are stored once in a global variable. If other subsystems wanted
63  * to use these hooks, a pointer to a set of bio_ops could be added
64  * to each buffer.
65  */
66 extern struct bio_ops {
67 	void	(*io_start)(struct buf *);
68 	void	(*io_complete)(struct buf *);
69 	void	(*io_deallocate)(struct buf *);
70 	int	(*io_countdeps)(struct buf *, int);
71 } bioops;
72 
73 struct vm_object;
74 struct vm_page;
75 
76 typedef uint32_t b_xflags_t;
77 
78 /*
79  * The buffer header describes an I/O operation in the kernel.
80  *
81  * NOTES:
82  *	b_bufsize, b_bcount.  b_bufsize is the allocation size of the
83  *	buffer, either DEV_BSIZE or PAGE_SIZE aligned.  b_bcount is the
84  *	originally requested buffer size and can serve as a bounds check
85  *	against EOF.  For most, but not all uses, b_bcount == b_bufsize.
86  *
87  *	b_dirtyoff, b_dirtyend.  Buffers support piecemeal, unaligned
88  *	ranges of dirty data that need to be written to backing store.
89  *	The range is typically clipped at b_bcount ( not b_bufsize ).
90  *
91  *	b_resid.  Number of bytes remaining in I/O.  After an I/O operation
92  *	completes, b_resid is usually 0 indicating 100% success.
93  *
94  *	All fields are protected by the buffer lock except those marked:
95  *		V - Protected by owning bufobj lock
96  *		Q - Protected by the buf queue lock
97  *		D - Protected by an dependency implementation specific lock
98  */
99 struct buf {
100 	struct bufobj	*b_bufobj;
101 	long		b_bcount;
102 	void		*b_caller1;
103 	caddr_t		b_data;
104 	int		b_error;
105 	uint16_t	b_iocmd;	/* BIO_* bio_cmd from bio.h */
106 	uint16_t	b_ioflags;	/* BIO_* bio_flags from bio.h */
107 	off_t		b_iooffset;
108 	long		b_resid;
109 	void	(*b_iodone)(struct buf *);
110 	void	(*b_ckhashcalc)(struct buf *);
111 	uint64_t	b_ckhash;	/* B_CKHASH requested check-hash */
112 	daddr_t b_blkno;		/* Underlying physical block number. */
113 	off_t	b_offset;		/* Offset into file. */
114 	TAILQ_ENTRY(buf) b_bobufs;	/* (V) Buffer's associated vnode. */
115 	uint32_t	b_vflags;	/* (V) BV_* flags */
116 	uint8_t		b_qindex;	/* (Q) buffer queue index */
117 	uint8_t		b_domain;	/* (Q) buf domain this resides in */
118 	uint16_t	b_subqueue;	/* (Q) per-cpu q if any */
119 	uint32_t	b_flags;	/* B_* flags. */
120 	b_xflags_t b_xflags;		/* extra flags */
121 	struct lock b_lock;		/* Buffer lock */
122 	long	b_bufsize;		/* Allocated buffer size. */
123 	int	b_runningbufspace;	/* when I/O is running, pipelining */
124 	int	b_kvasize;		/* size of kva for buffer */
125 	int	b_dirtyoff;		/* Offset in buffer of dirty region. */
126 	int	b_dirtyend;		/* Offset of end of dirty region. */
127 	caddr_t	b_kvabase;		/* base kva for buffer */
128 	daddr_t b_lblkno;		/* Logical block number. */
129 	struct	vnode *b_vp;		/* Device vnode. */
130 	struct	ucred *b_rcred;		/* Read credentials reference. */
131 	struct	ucred *b_wcred;		/* Write credentials reference. */
132 	union {
133 		TAILQ_ENTRY(buf) b_freelist; /* (Q) */
134 		struct {
135 			void	(*b_pgiodone)(void *, vm_page_t *, int, int);
136 			int	b_pgbefore;
137 			int	b_pgafter;
138 		};
139 	};
140 	union	cluster_info {
141 		TAILQ_HEAD(cluster_list_head, buf) cluster_head;
142 		TAILQ_ENTRY(buf) cluster_entry;
143 	} b_cluster;
144 	struct	vm_page *b_pages[btoc(MAXPHYS)];
145 	int		b_npages;
146 	struct	workhead b_dep;		/* (D) List of filesystem dependencies. */
147 	void	*b_fsprivate1;
148 	void	*b_fsprivate2;
149 	void	*b_fsprivate3;
150 
151 #if defined(FULL_BUF_TRACKING)
152 #define BUF_TRACKING_SIZE	32
153 #define BUF_TRACKING_ENTRY(x)	((x) & (BUF_TRACKING_SIZE - 1))
154 	const char	*b_io_tracking[BUF_TRACKING_SIZE];
155 	uint32_t	b_io_tcnt;
156 #elif defined(BUF_TRACKING)
157 	const char	*b_io_tracking;
158 #endif
159 };
160 
161 #define b_object	b_bufobj->bo_object
162 
163 /*
164  * These flags are kept in b_flags.
165  *
166  * Notes:
167  *
168  *	B_ASYNC		VOP calls on bp's are usually async whether or not
169  *			B_ASYNC is set, but some subsystems, such as NFS, like
170  *			to know what is best for the caller so they can
171  *			optimize the I/O.
172  *
173  *	B_PAGING	Indicates that bp is being used by the paging system or
174  *			some paging system and that the bp is not linked into
175  *			the b_vp's clean/dirty linked lists or ref counts.
176  *			Buffer vp reassignments are illegal in this case.
177  *
178  *	B_CACHE		This may only be set if the buffer is entirely valid.
179  *			The situation where B_DELWRI is set and B_CACHE is
180  *			clear MUST be committed to disk by getblk() so
181  *			B_DELWRI can also be cleared.  See the comments for
182  *			getblk() in kern/vfs_bio.c.  If B_CACHE is clear,
183  *			the caller is expected to clear BIO_ERROR and B_INVAL,
184  *			set BIO_READ, and initiate an I/O.
185  *
186  *			The 'entire buffer' is defined to be the range from
187  *			0 through b_bcount.
188  *
189  *	B_MALLOC	Request that the buffer be allocated from the malloc
190  *			pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned.
191  *
192  *	B_CLUSTEROK	This flag is typically set for B_DELWRI buffers
193  *			by filesystems that allow clustering when the buffer
194  *			is fully dirty and indicates that it may be clustered
195  *			with other adjacent dirty buffers.  Note the clustering
196  *			may not be used with the stage 1 data write under NFS
197  *			but may be used for the commit rpc portion.
198  *
199  *	B_INVALONERR	This flag is set on dirty buffers.  It specifies that a
200  *			write error should forcibly invalidate the buffer
201  *			contents.  This flag should be used with caution, as it
202  *			discards data.  It is incompatible with B_ASYNC.
203  *
204  *	B_VMIO		Indicates that the buffer is tied into an VM object.
205  *			The buffer's data is always PAGE_SIZE aligned even
206  *			if b_bufsize and b_bcount are not.  ( b_bufsize is
207  *			always at least DEV_BSIZE aligned, though ).
208  *
209  *	B_DIRECT	Hint that we should attempt to completely free
210  *			the pages underlying the buffer.  B_DIRECT is
211  *			sticky until the buffer is released and typically
212  *			only has an effect when B_RELBUF is also set.
213  *
214  */
215 
216 #define	B_AGE		0x00000001	/* Move to age queue when I/O done. */
217 #define	B_NEEDCOMMIT	0x00000002	/* Append-write in progress. */
218 #define	B_ASYNC		0x00000004	/* Start I/O, do not wait. */
219 #define	B_DIRECT	0x00000008	/* direct I/O flag (pls free vmio) */
220 #define	B_DEFERRED	0x00000010	/* Skipped over for cleaning */
221 #define	B_CACHE		0x00000020	/* Bread found us in the cache. */
222 #define	B_VALIDSUSPWRT	0x00000040	/* Valid write during suspension. */
223 #define	B_DELWRI	0x00000080	/* Delay I/O until buffer reused. */
224 #define	B_CKHASH	0x00000100	/* checksum hash calculated on read */
225 #define	B_DONE		0x00000200	/* I/O completed. */
226 #define	B_EINTR		0x00000400	/* I/O was interrupted */
227 #define	B_NOREUSE	0x00000800	/* Contents not reused once released. */
228 #define	B_REUSE		0x00001000	/* Contents reused, second chance. */
229 #define	B_INVAL		0x00002000	/* Does not contain valid info. */
230 #define	B_BARRIER	0x00004000	/* Write this and all preceding first. */
231 #define	B_NOCACHE	0x00008000	/* Do not cache block after use. */
232 #define	B_MALLOC	0x00010000	/* malloced b_data */
233 #define	B_CLUSTEROK	0x00020000	/* Pagein op, so swap() can count it. */
234 #define	B_INVALONERR	0x00040000	/* Invalidate on write error. */
235 #define	B_00080000	0x00080000	/* Available flag. */
236 #define	B_00100000	0x00100000	/* Available flag. */
237 #define	B_00200000	0x00200000	/* Available flag. */
238 #define	B_RELBUF	0x00400000	/* Release VMIO buffer. */
239 #define	B_FS_FLAG1	0x00800000	/* Available flag for FS use. */
240 #define	B_NOCOPY	0x01000000	/* Don't copy-on-write this buf. */
241 #define	B_INFREECNT	0x02000000	/* buf is counted in numfreebufs */
242 #define	B_PAGING	0x04000000	/* volatile paging I/O -- bypass VMIO */
243 #define B_MANAGED	0x08000000	/* Managed by FS. */
244 #define B_RAM		0x10000000	/* Read ahead mark (flag) */
245 #define B_VMIO		0x20000000	/* VMIO flag */
246 #define B_CLUSTER	0x40000000	/* pagein op, so swap() can count it */
247 #define B_REMFREE	0x80000000	/* Delayed bremfree */
248 
249 #define PRINT_BUF_FLAGS "\20\40remfree\37cluster\36vmio\35ram\34managed" \
250 	"\33paging\32infreecnt\31nocopy\30b23\27relbuf\26b21\25b20" \
251 	"\24b19\23invalonerr\22clusterok\21malloc\20nocache\17b14\16inval" \
252 	"\15reuse\14noreuse\13eintr\12done\11b8\10delwri" \
253 	"\7validsuspwrt\6cache\5deferred\4direct\3async\2needcommit\1age"
254 
255 /*
256  * These flags are kept in b_xflags.
257  *
258  * BX_FSPRIV reserves a set of eight flags that may be used by individual
259  * filesystems for their own purpose. Their specific definitions are
260  * found in the header files for each filesystem that uses them.
261  */
262 #define	BX_VNDIRTY	0x00000001	/* On vnode dirty list */
263 #define	BX_VNCLEAN	0x00000002	/* On vnode clean list */
264 #define	BX_CVTENXIO	0x00000004	/* Convert errors to ENXIO */
265 #define	BX_BKGRDWRITE	0x00000010	/* Do writes in background */
266 #define	BX_BKGRDMARKER	0x00000020	/* Mark buffer for splay tree */
267 #define	BX_ALTDATA	0x00000040	/* Holds extended data */
268 #define	BX_FSPRIV	0x00FF0000	/* Filesystem-specific flags mask */
269 
270 #define	PRINT_BUF_XFLAGS "\20\7altdata\6bkgrdmarker\5bkgrdwrite\3cvtenxio" \
271 	"\2clean\1dirty"
272 
273 #define	NOOFFSET	(-1LL)		/* No buffer offset calculated yet */
274 
275 /*
276  * These flags are kept in b_vflags.
277  */
278 #define	BV_SCANNED	0x00000001	/* VOP_FSYNC funcs mark written bufs */
279 #define	BV_BKGRDINPROG	0x00000002	/* Background write in progress */
280 #define	BV_BKGRDWAIT	0x00000004	/* Background write waiting */
281 #define	BV_BKGRDERR	0x00000008	/* Error from background write */
282 
283 #define	PRINT_BUF_VFLAGS "\20\4bkgrderr\3bkgrdwait\2bkgrdinprog\1scanned"
284 
285 #ifdef _KERNEL
286 
287 #ifndef NSWBUF_MIN
288 #define	NSWBUF_MIN	16
289 #endif
290 
291 /*
292  * Buffer locking
293  */
294 extern const char *buf_wmesg;		/* Default buffer lock message */
295 #define BUF_WMESG "bufwait"
296 #include <sys/proc.h>			/* XXX for curthread */
297 #include <sys/mutex.h>
298 
299 /*
300  * Initialize a lock.
301  */
302 #define BUF_LOCKINIT(bp)						\
303 	lockinit(&(bp)->b_lock, PRIBIO + 4, buf_wmesg, 0, LK_NEW)
304 /*
305  *
306  * Get a lock sleeping non-interruptably until it becomes available.
307  */
308 #define	BUF_LOCK(bp, locktype, interlock)				\
309 	_lockmgr_args_rw(&(bp)->b_lock, (locktype), (interlock),	\
310 	    LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT,		\
311 	    LOCK_FILE, LOCK_LINE)
312 
313 /*
314  * Get a lock sleeping with specified interruptably and timeout.
315  */
316 #define	BUF_TIMELOCK(bp, locktype, interlock, wmesg, catch, timo)	\
317 	_lockmgr_args_rw(&(bp)->b_lock, (locktype) | LK_TIMELOCK,	\
318 	    (interlock), (wmesg), (PRIBIO + 4) | (catch), (timo),	\
319 	    LOCK_FILE, LOCK_LINE)
320 
321 /*
322  * Release a lock. Only the acquiring process may free the lock unless
323  * it has been handed off to biodone.
324  */
325 #define	BUF_UNLOCK(bp) do {						\
326 	KASSERT(((bp)->b_flags & B_REMFREE) == 0,			\
327 	    ("BUF_UNLOCK %p while B_REMFREE is still set.", (bp)));	\
328 									\
329 	(void)_lockmgr_args(&(bp)->b_lock, LK_RELEASE, NULL,		\
330 	    LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT,		\
331 	    LOCK_FILE, LOCK_LINE);					\
332 } while (0)
333 
334 /*
335  * Check if a buffer lock is recursed.
336  */
337 #define	BUF_LOCKRECURSED(bp)						\
338 	lockmgr_recursed(&(bp)->b_lock)
339 
340 /*
341  * Check if a buffer lock is currently held.
342  */
343 #define	BUF_ISLOCKED(bp)						\
344 	lockstatus(&(bp)->b_lock)
345 /*
346  * Free a buffer lock.
347  */
348 #define BUF_LOCKFREE(bp) 						\
349 	lockdestroy(&(bp)->b_lock)
350 
351 /*
352  * Print informations on a buffer lock.
353  */
354 #define BUF_LOCKPRINTINFO(bp) 						\
355 	lockmgr_printinfo(&(bp)->b_lock)
356 
357 /*
358  * Buffer lock assertions.
359  */
360 #if defined(INVARIANTS) && defined(INVARIANT_SUPPORT)
361 #define	BUF_ASSERT_LOCKED(bp)						\
362 	_lockmgr_assert(&(bp)->b_lock, KA_LOCKED, LOCK_FILE, LOCK_LINE)
363 #define	BUF_ASSERT_SLOCKED(bp)						\
364 	_lockmgr_assert(&(bp)->b_lock, KA_SLOCKED, LOCK_FILE, LOCK_LINE)
365 #define	BUF_ASSERT_XLOCKED(bp)						\
366 	_lockmgr_assert(&(bp)->b_lock, KA_XLOCKED, LOCK_FILE, LOCK_LINE)
367 #define	BUF_ASSERT_UNLOCKED(bp)						\
368 	_lockmgr_assert(&(bp)->b_lock, KA_UNLOCKED, LOCK_FILE, LOCK_LINE)
369 #else
370 #define	BUF_ASSERT_LOCKED(bp)
371 #define	BUF_ASSERT_SLOCKED(bp)
372 #define	BUF_ASSERT_XLOCKED(bp)
373 #define	BUF_ASSERT_UNLOCKED(bp)
374 #endif
375 
376 #ifdef _SYS_PROC_H_	/* Avoid #include <sys/proc.h> pollution */
377 /*
378  * When initiating asynchronous I/O, change ownership of the lock to the
379  * kernel. Once done, the lock may legally released by biodone. The
380  * original owning process can no longer acquire it recursively, but must
381  * wait until the I/O is completed and the lock has been freed by biodone.
382  */
383 #define	BUF_KERNPROC(bp)						\
384 	_lockmgr_disown(&(bp)->b_lock, LOCK_FILE, LOCK_LINE)
385 #endif
386 
387 #endif /* _KERNEL */
388 
389 struct buf_queue_head {
390 	TAILQ_HEAD(buf_queue, buf) queue;
391 	daddr_t last_pblkno;
392 	struct	buf *insert_point;
393 	struct	buf *switch_point;
394 };
395 
396 /*
397  * This structure describes a clustered I/O.
398  */
399 struct cluster_save {
400 	long	bs_bcount;		/* Saved b_bcount. */
401 	long	bs_bufsize;		/* Saved b_bufsize. */
402 	int	bs_nchildren;		/* Number of associated buffers. */
403 	struct buf **bs_children;	/* List of associated buffers. */
404 };
405 
406 #ifdef _KERNEL
407 
408 static __inline int
409 bwrite(struct buf *bp)
410 {
411 
412 	KASSERT(bp->b_bufobj != NULL, ("bwrite: no bufobj bp=%p", bp));
413 	KASSERT(bp->b_bufobj->bo_ops != NULL, ("bwrite: no bo_ops bp=%p", bp));
414 	KASSERT(bp->b_bufobj->bo_ops->bop_write != NULL,
415 	    ("bwrite: no bop_write bp=%p", bp));
416 	return (BO_WRITE(bp->b_bufobj, bp));
417 }
418 
419 static __inline void
420 bstrategy(struct buf *bp)
421 {
422 
423 	KASSERT(bp->b_bufobj != NULL, ("bstrategy: no bufobj bp=%p", bp));
424 	KASSERT(bp->b_bufobj->bo_ops != NULL,
425 	    ("bstrategy: no bo_ops bp=%p", bp));
426 	KASSERT(bp->b_bufobj->bo_ops->bop_strategy != NULL,
427 	    ("bstrategy: no bop_strategy bp=%p", bp));
428 	BO_STRATEGY(bp->b_bufobj, bp);
429 }
430 
431 static __inline void
432 buf_start(struct buf *bp)
433 {
434 	if (bioops.io_start)
435 		(*bioops.io_start)(bp);
436 }
437 
438 static __inline void
439 buf_complete(struct buf *bp)
440 {
441 	if (bioops.io_complete)
442 		(*bioops.io_complete)(bp);
443 }
444 
445 static __inline void
446 buf_deallocate(struct buf *bp)
447 {
448 	if (bioops.io_deallocate)
449 		(*bioops.io_deallocate)(bp);
450 }
451 
452 static __inline int
453 buf_countdeps(struct buf *bp, int i)
454 {
455 	if (bioops.io_countdeps)
456 		return ((*bioops.io_countdeps)(bp, i));
457 	else
458 		return (0);
459 }
460 
461 static __inline void
462 buf_track(struct buf *bp __unused, const char *location __unused)
463 {
464 
465 #if defined(FULL_BUF_TRACKING)
466 	bp->b_io_tracking[BUF_TRACKING_ENTRY(bp->b_io_tcnt++)] = location;
467 #elif defined(BUF_TRACKING)
468 	bp->b_io_tracking = location;
469 #endif
470 }
471 
472 #endif /* _KERNEL */
473 
474 /*
475  * Zero out the buffer's data area.
476  */
477 #define	clrbuf(bp) {							\
478 	bzero((bp)->b_data, (u_int)(bp)->b_bcount);			\
479 	(bp)->b_resid = 0;						\
480 }
481 
482 /*
483  * Flags for getblk's last parameter.
484  */
485 #define	GB_LOCK_NOWAIT	0x0001		/* Fail if we block on a buf lock. */
486 #define	GB_NOCREAT	0x0002		/* Don't create a buf if not found. */
487 #define	GB_NOWAIT_BD	0x0004		/* Do not wait for bufdaemon. */
488 #define	GB_UNMAPPED	0x0008		/* Do not mmap buffer pages. */
489 #define	GB_KVAALLOC	0x0010		/* But allocate KVA. */
490 #define	GB_CKHASH	0x0020		/* If reading, calc checksum hash */
491 #define	GB_NOSPARSE	0x0040		/* Do not instantiate holes */
492 #define	GB_CVTENXIO	0x0080		/* Convert errors to ENXIO */
493 
494 #ifdef _KERNEL
495 extern int	nbuf;			/* The number of buffer headers */
496 extern long	maxswzone;		/* Max KVA for swap structures */
497 extern long	maxbcache;		/* Max KVA for buffer cache */
498 extern int	maxbcachebuf;		/* Max buffer cache block size */
499 extern long	runningbufspace;
500 extern long	hibufspace;
501 extern int	dirtybufthresh;
502 extern int	bdwriteskip;
503 extern int	dirtybufferflushes;
504 extern int	altbufferflushes;
505 extern int	nswbuf;			/* Number of swap I/O buffer headers. */
506 extern caddr_t	unmapped_buf;	/* Data address for unmapped buffers. */
507 
508 static inline int
509 buf_mapped(struct buf *bp)
510 {
511 
512 	return (bp->b_data != unmapped_buf);
513 }
514 
515 void	runningbufwakeup(struct buf *);
516 void	waitrunningbufspace(void);
517 caddr_t	kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est);
518 void	bufinit(void);
519 void	bufshutdown(int);
520 void	bdata2bio(struct buf *bp, struct bio *bip);
521 void	bwillwrite(void);
522 int	buf_dirty_count_severe(void);
523 void	bremfree(struct buf *);
524 void	bremfreef(struct buf *);	/* XXX Force bremfree, only for nfs. */
525 #define bread(vp, blkno, size, cred, bpp) \
526 	    breadn_flags(vp, blkno, blkno, size, NULL, NULL, 0, cred, 0, \
527 		NULL, bpp)
528 #define bread_gb(vp, blkno, size, cred, gbflags, bpp) \
529 	    breadn_flags(vp, blkno, blkno, size, NULL, NULL, 0, cred, \
530 		gbflags, NULL, bpp)
531 #define breadn(vp, blkno, size, rablkno, rabsize, cnt, cred, bpp) \
532 	    breadn_flags(vp, blkno, blkno, size, rablkno, rabsize, cnt, cred, \
533 		0, NULL, bpp)
534 int	breadn_flags(struct vnode *, daddr_t, daddr_t, int, daddr_t *, int *,
535 	    int, struct ucred *, int, void (*)(struct buf *), struct buf **);
536 void	bdwrite(struct buf *);
537 void	bawrite(struct buf *);
538 void	babarrierwrite(struct buf *);
539 int	bbarrierwrite(struct buf *);
540 void	bdirty(struct buf *);
541 void	bundirty(struct buf *);
542 void	bufstrategy(struct bufobj *, struct buf *);
543 void	brelse(struct buf *);
544 void	bqrelse(struct buf *);
545 int	vfs_bio_awrite(struct buf *);
546 void	vfs_busy_pages_acquire(struct buf *bp);
547 void	vfs_busy_pages_release(struct buf *bp);
548 struct buf *incore(struct bufobj *, daddr_t);
549 struct buf *gbincore(struct bufobj *, daddr_t);
550 struct buf *getblk(struct vnode *, daddr_t, int, int, int, int);
551 int	getblkx(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size,
552 	    int slpflag, int slptimeo, int flags, struct buf **bpp);
553 struct buf *geteblk(int, int);
554 int	bufwait(struct buf *);
555 int	bufwrite(struct buf *);
556 void	bufdone(struct buf *);
557 void	bd_speedup(void);
558 
559 extern uma_zone_t pbuf_zone;
560 uma_zone_t pbuf_zsecond_create(const char *name, int max);
561 
562 int	cluster_read(struct vnode *, u_quad_t, daddr_t, long,
563 	    struct ucred *, long, int, int, struct buf **);
564 int	cluster_wbuild(struct vnode *, long, daddr_t, int, int);
565 void	cluster_write(struct vnode *, struct buf *, u_quad_t, int, int);
566 void	vfs_bio_brelse(struct buf *bp, int ioflags);
567 void	vfs_bio_bzero_buf(struct buf *bp, int base, int size);
568 void	vfs_bio_clrbuf(struct buf *);
569 void	vfs_bio_set_flags(struct buf *bp, int ioflags);
570 void	vfs_bio_set_valid(struct buf *, int base, int size);
571 void	vfs_busy_pages(struct buf *, int clear_modify);
572 void	vfs_unbusy_pages(struct buf *);
573 int	vmapbuf(struct buf *, int);
574 void	vunmapbuf(struct buf *);
575 void	brelvp(struct buf *);
576 void	bgetvp(struct vnode *, struct buf *);
577 void	pbgetbo(struct bufobj *bo, struct buf *bp);
578 void	pbgetvp(struct vnode *, struct buf *);
579 void	pbrelbo(struct buf *);
580 void	pbrelvp(struct buf *);
581 int	allocbuf(struct buf *bp, int size);
582 void	reassignbuf(struct buf *);
583 void	bwait(struct buf *, u_char, const char *);
584 void	bdone(struct buf *);
585 
586 typedef daddr_t (vbg_get_lblkno_t)(struct vnode *, vm_ooffset_t);
587 typedef int (vbg_get_blksize_t)(struct vnode *, daddr_t);
588 int	vfs_bio_getpages(struct vnode *vp, struct vm_page **ma, int count,
589 	    int *rbehind, int *rahead, vbg_get_lblkno_t get_lblkno,
590 	    vbg_get_blksize_t get_blksize);
591 
592 #endif /* _KERNEL */
593 
594 #endif /* !_SYS_BUF_H_ */
595