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/10/sys/sys/buf.h 300060 2016-05-17 15:18:01Z pfg $
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 uint32_t b_vflags; /* (V) BV_* flags */
110 TAILQ_ENTRY(buf) b_freelist; /* (Q) Free list position inactive. */
111 unsigned short b_qindex; /* (Q) buffer queue index */
112 uint32_t b_flags; /* B_* flags. */
113 b_xflags_t b_xflags; /* extra flags */
114 struct lock b_lock; /* Buffer lock */
115 long b_bufsize; /* Allocated buffer size. */
116 long b_runningbufspace; /* when I/O is running, pipelining */
117 caddr_t b_kvabase; /* base kva for buffer */
118 caddr_t b_kvaalloc; /* allocated kva for B_KVAALLOC */
119 int b_kvasize; /* size of kva for buffer */
120 daddr_t b_lblkno; /* Logical block number. */
121 struct vnode *b_vp; /* Device vnode. */
122 int b_dirtyoff; /* Offset in buffer of dirty region. */
123 int b_dirtyend; /* Offset of end of dirty region. */
124 struct ucred *b_rcred; /* Read credentials reference. */
125 struct ucred *b_wcred; /* Write credentials reference. */
126 void *b_saveaddr; /* Original b_addr for physio. */
127 union pager_info {
128 int pg_reqpage;
129 } b_pager;
130 union cluster_info {
131 TAILQ_HEAD(cluster_list_head, buf) cluster_head;
132 TAILQ_ENTRY(buf) cluster_entry;
133 } b_cluster;
134 struct vm_page *b_pages[btoc(MAXPHYS)];
135 int b_npages;
136 struct workhead b_dep; /* (D) List of filesystem dependencies. */
137 void *b_fsprivate1;
138 void *b_fsprivate2;
139 void *b_fsprivate3;
140 int b_pin_count;
141 };
142
143 #define b_object b_bufobj->bo_object
144
145 /*
146 * These flags are kept in b_flags.
147 *
148 * Notes:
149 *
150 * B_ASYNC VOP calls on bp's are usually async whether or not
151 * B_ASYNC is set, but some subsystems, such as NFS, like
152 * to know what is best for the caller so they can
153 * optimize the I/O.
154 *
155 * B_PAGING Indicates that bp is being used by the paging system or
156 * some paging system and that the bp is not linked into
157 * the b_vp's clean/dirty linked lists or ref counts.
158 * Buffer vp reassignments are illegal in this case.
159 *
160 * B_CACHE This may only be set if the buffer is entirely valid.
161 * The situation where B_DELWRI is set and B_CACHE is
162 * clear MUST be committed to disk by getblk() so
163 * B_DELWRI can also be cleared. See the comments for
164 * getblk() in kern/vfs_bio.c. If B_CACHE is clear,
165 * the caller is expected to clear BIO_ERROR and B_INVAL,
166 * set BIO_READ, and initiate an I/O.
167 *
168 * The 'entire buffer' is defined to be the range from
169 * 0 through b_bcount.
170 *
171 * B_MALLOC Request that the buffer be allocated from the malloc
172 * pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned.
173 *
174 * B_CLUSTEROK This flag is typically set for B_DELWRI buffers
175 * by filesystems that allow clustering when the buffer
176 * is fully dirty and indicates that it may be clustered
177 * with other adjacent dirty buffers. Note the clustering
178 * may not be used with the stage 1 data write under NFS
179 * but may be used for the commit rpc portion.
180 *
181 * B_VMIO Indicates that the buffer is tied into an VM object.
182 * The buffer's data is always PAGE_SIZE aligned even
183 * if b_bufsize and b_bcount are not. ( b_bufsize is
184 * always at least DEV_BSIZE aligned, though ).
185 *
186 * B_DIRECT Hint that we should attempt to completely free
187 * the pages underlying the buffer. B_DIRECT is
188 * sticky until the buffer is released and typically
189 * only has an effect when B_RELBUF is also set.
190 *
191 */
192
193 #define B_AGE 0x00000001 /* Move to age queue when I/O done. */
194 #define B_NEEDCOMMIT 0x00000002 /* Append-write in progress. */
195 #define B_ASYNC 0x00000004 /* Start I/O, do not wait. */
196 #define B_DIRECT 0x00000008 /* direct I/O flag (pls free vmio) */
197 #define B_DEFERRED 0x00000010 /* Skipped over for cleaning */
198 #define B_CACHE 0x00000020 /* Bread found us in the cache. */
199 #define B_VALIDSUSPWRT 0x00000040 /* Valid write during suspension. */
200 #define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */
201 #define B_PERSISTENT 0x00000100 /* Perm. ref'ed while EXT2FS mounted. */
202 #define B_DONE 0x00000200 /* I/O completed. */
203 #define B_EINTR 0x00000400 /* I/O was interrupted */
204 #define B_UNMAPPED 0x00000800 /* KVA is not mapped. */
205 #define B_KVAALLOC 0x00001000 /* But allocated. */
206 #define B_INVAL 0x00002000 /* Does not contain valid info. */
207 #define B_BARRIER 0x00004000 /* Write this and all preceding first. */
208 #define B_NOCACHE 0x00008000 /* Do not cache block after use. */
209 #define B_MALLOC 0x00010000 /* malloced b_data */
210 #define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */
211 #define B_000400000 0x00040000 /* Available flag. */
212 #define B_000800000 0x00080000 /* Available flag. */
213 #define B_00100000 0x00100000 /* Available flag. */
214 #define B_DIRTY 0x00200000 /* Needs writing later (in EXT2FS). */
215 #define B_RELBUF 0x00400000 /* Release VMIO buffer. */
216 #define B_00800000 0x00800000 /* Available flag. */
217 #define B_NOCOPY 0x01000000 /* Don't copy-on-write this buf. */
218 #define B_INFREECNT 0x02000000 /* buf is counted in numfreebufs */
219 #define B_PAGING 0x04000000 /* volatile paging I/O -- bypass VMIO */
220 #define B_MANAGED 0x08000000 /* Managed by FS. */
221 #define B_RAM 0x10000000 /* Read ahead mark (flag) */
222 #define B_VMIO 0x20000000 /* VMIO flag */
223 #define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */
224 #define B_REMFREE 0x80000000 /* Delayed bremfree */
225
226 #define PRINT_BUF_FLAGS "\20\40remfree\37cluster\36vmio\35ram\34managed" \
227 "\33paging\32infreecnt\31nocopy\30b23\27relbuf\26dirty\25b20" \
228 "\24b19\23b18\22clusterok\21malloc\20nocache\17b14\16inval" \
229 "\15kvaalloc\14unmapped\13eintr\12done\11persist\10delwri" \
230 "\7validsuspwrt\6cache\5deferred\4direct\3async\2needcommit\1age"
231
232 /*
233 * These flags are kept in b_xflags.
234 */
235 #define BX_VNDIRTY 0x00000001 /* On vnode dirty list */
236 #define BX_VNCLEAN 0x00000002 /* On vnode clean list */
237 #define BX_BKGRDWRITE 0x00000010 /* Do writes in background */
238 #define BX_BKGRDMARKER 0x00000020 /* Mark buffer for splay tree */
239 #define BX_ALTDATA 0x00000040 /* Holds extended data */
240
241 #define PRINT_BUF_XFLAGS "\20\7altdata\6bkgrdmarker\5bkgrdwrite\2clean\1dirty"
242
243 #define NOOFFSET (-1LL) /* No buffer offset calculated yet */
244
245 /*
246 * These flags are kept in b_vflags.
247 */
248 #define BV_SCANNED 0x00000001 /* VOP_FSYNC funcs mark written bufs */
249 #define BV_BKGRDINPROG 0x00000002 /* Background write in progress */
250 #define BV_BKGRDWAIT 0x00000004 /* Background write waiting */
251 #define BV_BKGRDERR 0x00000008 /* Error from background write */
252
253 #define PRINT_BUF_VFLAGS "\20\4bkgrderr\3bkgrdwait\2bkgrdinprog\1scanned"
254
255 #ifdef _KERNEL
256 /*
257 * Buffer locking
258 */
259 extern const char *buf_wmesg; /* Default buffer lock message */
260 #define BUF_WMESG "bufwait"
261 #include <sys/proc.h> /* XXX for curthread */
262 #include <sys/mutex.h>
263
264 /*
265 * Initialize a lock.
266 */
267 #define BUF_LOCKINIT(bp) \
268 lockinit(&(bp)->b_lock, PRIBIO + 4, buf_wmesg, 0, 0)
269 /*
270 *
271 * Get a lock sleeping non-interruptably until it becomes available.
272 */
273 #define BUF_LOCK(bp, locktype, interlock) \
274 _lockmgr_args_rw(&(bp)->b_lock, (locktype), (interlock), \
275 LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT, \
276 LOCK_FILE, LOCK_LINE)
277
278 /*
279 * Get a lock sleeping with specified interruptably and timeout.
280 */
281 #define BUF_TIMELOCK(bp, locktype, interlock, wmesg, catch, timo) \
282 _lockmgr_args_rw(&(bp)->b_lock, (locktype) | LK_TIMELOCK, \
283 (interlock), (wmesg), (PRIBIO + 4) | (catch), (timo), \
284 LOCK_FILE, LOCK_LINE)
285
286 /*
287 * Release a lock. Only the acquiring process may free the lock unless
288 * it has been handed off to biodone.
289 */
290 #define BUF_UNLOCK(bp) do { \
291 KASSERT(((bp)->b_flags & B_REMFREE) == 0, \
292 ("BUF_UNLOCK %p while B_REMFREE is still set.", (bp))); \
293 \
294 (void)_lockmgr_args(&(bp)->b_lock, LK_RELEASE, NULL, \
295 LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT, \
296 LOCK_FILE, LOCK_LINE); \
297 } while (0)
298
299 /*
300 * Check if a buffer lock is recursed.
301 */
302 #define BUF_LOCKRECURSED(bp) \
303 lockmgr_recursed(&(bp)->b_lock)
304
305 /*
306 * Check if a buffer lock is currently held.
307 */
308 #define BUF_ISLOCKED(bp) \
309 lockstatus(&(bp)->b_lock)
310 /*
311 * Free a buffer lock.
312 */
313 #define BUF_LOCKFREE(bp) \
314 lockdestroy(&(bp)->b_lock)
315
316 /*
317 * Print informations on a buffer lock.
318 */
319 #define BUF_LOCKPRINTINFO(bp) \
320 lockmgr_printinfo(&(bp)->b_lock)
321
322 /*
323 * Buffer lock assertions.
324 */
325 #if defined(INVARIANTS) && defined(INVARIANT_SUPPORT)
326 #define BUF_ASSERT_LOCKED(bp) \
327 _lockmgr_assert(&(bp)->b_lock, KA_LOCKED, LOCK_FILE, LOCK_LINE)
328 #define BUF_ASSERT_SLOCKED(bp) \
329 _lockmgr_assert(&(bp)->b_lock, KA_SLOCKED, LOCK_FILE, LOCK_LINE)
330 #define BUF_ASSERT_XLOCKED(bp) \
331 _lockmgr_assert(&(bp)->b_lock, KA_XLOCKED, LOCK_FILE, LOCK_LINE)
332 #define BUF_ASSERT_UNLOCKED(bp) \
333 _lockmgr_assert(&(bp)->b_lock, KA_UNLOCKED, LOCK_FILE, LOCK_LINE)
334 #define BUF_ASSERT_HELD(bp)
335 #define BUF_ASSERT_UNHELD(bp)
336 #else
337 #define BUF_ASSERT_LOCKED(bp)
338 #define BUF_ASSERT_SLOCKED(bp)
339 #define BUF_ASSERT_XLOCKED(bp)
340 #define BUF_ASSERT_UNLOCKED(bp)
341 #define BUF_ASSERT_HELD(bp)
342 #define BUF_ASSERT_UNHELD(bp)
343 #endif
344
345 #ifdef _SYS_PROC_H_ /* Avoid #include <sys/proc.h> pollution */
346 /*
347 * When initiating asynchronous I/O, change ownership of the lock to the
348 * kernel. Once done, the lock may legally released by biodone. The
349 * original owning process can no longer acquire it recursively, but must
350 * wait until the I/O is completed and the lock has been freed by biodone.
351 */
352 #define BUF_KERNPROC(bp) \
353 _lockmgr_disown(&(bp)->b_lock, LOCK_FILE, LOCK_LINE)
354 #endif
355
356 /*
357 * Find out if the lock has waiters or not.
358 */
359 #define BUF_LOCKWAITERS(bp) \
360 lockmgr_waiters(&(bp)->b_lock)
361
362 #endif /* _KERNEL */
363
364 struct buf_queue_head {
365 TAILQ_HEAD(buf_queue, buf) queue;
366 daddr_t last_pblkno;
367 struct buf *insert_point;
368 struct buf *switch_point;
369 };
370
371 /*
372 * This structure describes a clustered I/O. It is stored in the b_saveaddr
373 * field of the buffer on which I/O is done. At I/O completion, cluster
374 * callback uses the structure to parcel I/O's to individual buffers, and
375 * then free's this structure.
376 */
377 struct cluster_save {
378 long bs_bcount; /* Saved b_bcount. */
379 long bs_bufsize; /* Saved b_bufsize. */
380 void *bs_saveaddr; /* Saved b_addr. */
381 int bs_nchildren; /* Number of associated buffers. */
382 struct buf **bs_children; /* List of associated buffers. */
383 };
384
385 #ifdef _KERNEL
386
387 static __inline int
bwrite(struct buf * bp)388 bwrite(struct buf *bp)
389 {
390
391 KASSERT(bp->b_bufobj != NULL, ("bwrite: no bufobj bp=%p", bp));
392 KASSERT(bp->b_bufobj->bo_ops != NULL, ("bwrite: no bo_ops bp=%p", bp));
393 KASSERT(bp->b_bufobj->bo_ops->bop_write != NULL,
394 ("bwrite: no bop_write bp=%p", bp));
395 return (BO_WRITE(bp->b_bufobj, bp));
396 }
397
398 static __inline void
bstrategy(struct buf * bp)399 bstrategy(struct buf *bp)
400 {
401
402 KASSERT(bp->b_bufobj != NULL, ("bstrategy: no bufobj bp=%p", bp));
403 KASSERT(bp->b_bufobj->bo_ops != NULL,
404 ("bstrategy: no bo_ops bp=%p", bp));
405 KASSERT(bp->b_bufobj->bo_ops->bop_strategy != NULL,
406 ("bstrategy: no bop_strategy bp=%p", bp));
407 BO_STRATEGY(bp->b_bufobj, bp);
408 }
409
410 static __inline void
buf_start(struct buf * bp)411 buf_start(struct buf *bp)
412 {
413 if (bioops.io_start)
414 (*bioops.io_start)(bp);
415 }
416
417 static __inline void
buf_complete(struct buf * bp)418 buf_complete(struct buf *bp)
419 {
420 if (bioops.io_complete)
421 (*bioops.io_complete)(bp);
422 }
423
424 static __inline void
buf_deallocate(struct buf * bp)425 buf_deallocate(struct buf *bp)
426 {
427 if (bioops.io_deallocate)
428 (*bioops.io_deallocate)(bp);
429 }
430
431 static __inline int
buf_countdeps(struct buf * bp,int i)432 buf_countdeps(struct buf *bp, int i)
433 {
434 if (bioops.io_countdeps)
435 return ((*bioops.io_countdeps)(bp, i));
436 else
437 return (0);
438 }
439
440 #endif /* _KERNEL */
441
442 /*
443 * Zero out the buffer's data area.
444 */
445 #define clrbuf(bp) { \
446 bzero((bp)->b_data, (u_int)(bp)->b_bcount); \
447 (bp)->b_resid = 0; \
448 }
449
450 /*
451 * Flags for getblk's last parameter.
452 */
453 #define GB_LOCK_NOWAIT 0x0001 /* Fail if we block on a buf lock. */
454 #define GB_NOCREAT 0x0002 /* Don't create a buf if not found. */
455 #define GB_NOWAIT_BD 0x0004 /* Do not wait for bufdaemon. */
456 #define GB_UNMAPPED 0x0008 /* Do not mmap buffer pages. */
457 #define GB_KVAALLOC 0x0010 /* But allocate KVA. */
458
459 #ifdef _KERNEL
460 extern int nbuf; /* The number of buffer headers */
461 extern long maxswzone; /* Max KVA for swap structures */
462 extern long maxbcache; /* Max KVA for buffer cache */
463 extern long runningbufspace;
464 extern long hibufspace;
465 extern int dirtybufthresh;
466 extern int bdwriteskip;
467 extern int dirtybufferflushes;
468 extern int altbufferflushes;
469 extern struct buf *buf; /* The buffer headers. */
470 extern struct buf *swbuf; /* Swap I/O buffer headers. */
471 extern int nswbuf; /* Number of swap I/O buffer headers. */
472 extern int cluster_pbuf_freecnt; /* Number of pbufs for clusters */
473 extern int vnode_pbuf_freecnt; /* Number of pbufs for vnode pager */
474 extern caddr_t unmapped_buf;
475
476 void runningbufwakeup(struct buf *);
477 void waitrunningbufspace(void);
478 caddr_t kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est);
479 void bufinit(void);
480 void bdata2bio(struct buf *bp, struct bio *bip);
481 void bwillwrite(void);
482 int buf_dirty_count_severe(void);
483 void bremfree(struct buf *);
484 void bremfreef(struct buf *); /* XXX Force bremfree, only for nfs. */
485 #define bread(vp, blkno, size, cred, bpp) \
486 breadn_flags(vp, blkno, size, NULL, NULL, 0, cred, 0, bpp)
487 #define bread_gb(vp, blkno, size, cred, gbflags, bpp) \
488 breadn_flags(vp, blkno, size, NULL, NULL, 0, cred, \
489 gbflags, bpp)
490 #define breadn(vp, blkno, size, rablkno, rabsize, cnt, cred, bpp) \
491 breadn_flags(vp, blkno, size, rablkno, rabsize, cnt, cred, 0, bpp)
492 int breadn_flags(struct vnode *, daddr_t, int, daddr_t *, int *, int,
493 struct ucred *, int, struct buf **);
494 void breada(struct vnode *, daddr_t *, int *, int, struct ucred *);
495 void bdwrite(struct buf *);
496 void bawrite(struct buf *);
497 void babarrierwrite(struct buf *);
498 int bbarrierwrite(struct buf *);
499 void bdirty(struct buf *);
500 void bundirty(struct buf *);
501 void bufstrategy(struct bufobj *, struct buf *);
502 void brelse(struct buf *);
503 void bqrelse(struct buf *);
504 int vfs_bio_awrite(struct buf *);
505 void vfs_drain_busy_pages(struct buf *bp);
506 struct buf * getpbuf(int *);
507 struct buf *incore(struct bufobj *, daddr_t);
508 struct buf *gbincore(struct bufobj *, daddr_t);
509 struct buf *getblk(struct vnode *, daddr_t, int, int, int, int);
510 struct buf *geteblk(int, int);
511 int bufwait(struct buf *);
512 int bufwrite(struct buf *);
513 void bufdone(struct buf *);
514 void bufdone_finish(struct buf *);
515 void bd_speedup(void);
516
517 int cluster_read(struct vnode *, u_quad_t, daddr_t, long,
518 struct ucred *, long, int, int, struct buf **);
519 int cluster_wbuild(struct vnode *, long, daddr_t, int, int);
520 void cluster_write(struct vnode *, struct buf *, u_quad_t, int, int);
521 void vfs_bio_bzero_buf(struct buf *bp, int base, int size);
522 void vfs_bio_set_valid(struct buf *, int base, int size);
523 void vfs_bio_clrbuf(struct buf *);
524 void vfs_busy_pages(struct buf *, int clear_modify);
525 void vfs_unbusy_pages(struct buf *);
526 int vmapbuf(struct buf *, int);
527 void vunmapbuf(struct buf *);
528 void relpbuf(struct buf *, int *);
529 void brelvp(struct buf *);
530 void bgetvp(struct vnode *, struct buf *);
531 void pbgetbo(struct bufobj *bo, struct buf *bp);
532 void pbgetvp(struct vnode *, struct buf *);
533 void pbrelbo(struct buf *);
534 void pbrelvp(struct buf *);
535 int allocbuf(struct buf *bp, int size);
536 void reassignbuf(struct buf *);
537 struct buf *trypbuf(int *);
538 void bwait(struct buf *, u_char, const char *);
539 void bdone(struct buf *);
540 void bpin(struct buf *);
541 void bunpin(struct buf *);
542 void bunpin_wait(struct buf *);
543
544 #endif /* _KERNEL */
545
546 #endif /* !_SYS_BUF_H_ */
547