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: src/sys/sys/buf.h,v 1.88.2.10 2003/01/25 19:02:23 dillon Exp $
36 */
37
38 #ifndef _SYS_BUF2_H_
39 #define _SYS_BUF2_H_
40
41 #ifdef _KERNEL
42
43 #ifndef _SYS_BUF_H_
44 #include <sys/buf.h>
45 #endif
46 #ifndef _SYS_MOUNT_H_
47 #include <sys/mount.h>
48 #endif
49 #ifndef _SYS_VNODE_H_
50 #include <sys/vnode.h>
51 #endif
52 #ifndef _VM_VM_PAGE_H_
53 #include <vm/vm_page.h>
54 #endif
55
56 /*
57 * Initialize a lock.
58 */
59 #define BUF_LOCKINIT(bp) \
60 lockinit(&(bp)->b_lock, buf_wmesg, 0, LK_NOCOLLSTATS)
61
62 /*
63 *
64 * Get a lock sleeping non-interruptably until it becomes available.
65 *
66 * XXX lk_wmesg can race, but should not result in any operational issues.
67 */
68 static __inline int
BUF_LOCK(struct buf * bp,int locktype)69 BUF_LOCK(struct buf *bp, int locktype)
70 {
71 bp->b_lock.lk_wmesg = buf_wmesg;
72 return (lockmgr(&(bp)->b_lock, locktype));
73 }
74 /*
75 * Get a lock sleeping with specified interruptably and timeout.
76 *
77 * XXX lk_timo can race against other entities calling BUF_TIMELOCK,
78 * but will not interfere with entities calling BUF_LOCK since LK_TIMELOCK
79 * will not be set in that case.
80 *
81 * XXX lk_wmesg can race, but should not result in any operational issues.
82 */
83 static __inline int
BUF_TIMELOCK(struct buf * bp,int locktype,char * wmesg,int timo)84 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int timo)
85 {
86 bp->b_lock.lk_wmesg = wmesg;
87 bp->b_lock.lk_timo = timo;
88 return (lockmgr(&(bp)->b_lock, locktype | LK_TIMELOCK));
89 }
90 /*
91 * Release a lock. Only the acquiring process may free the lock unless
92 * it has been handed off to biodone.
93 */
94 static __inline void
BUF_UNLOCK(struct buf * bp)95 BUF_UNLOCK(struct buf *bp)
96 {
97 lockmgr(&(bp)->b_lock, LK_RELEASE);
98 }
99
100 /*
101 * When initiating asynchronous I/O, change ownership of the lock to the
102 * kernel. Once done, the lock may legally released by biodone. The
103 * original owning process can no longer acquire it recursively, but must
104 * wait until the I/O is completed and the lock has been freed by biodone.
105 */
106 static __inline void
BUF_KERNPROC(struct buf * bp)107 BUF_KERNPROC(struct buf *bp)
108 {
109 lockmgr_kernproc(&(bp)->b_lock);
110 }
111 /*
112 * Find out the number of references to a lock.
113 *
114 * The non-blocking version should only be used for assertions in cases
115 * where the buffer is expected to be owned or otherwise data stable.
116 */
117 static __inline int
BUF_LOCKINUSE(struct buf * bp)118 BUF_LOCKINUSE(struct buf *bp)
119 {
120 return (lockinuse(&(bp)->b_lock));
121 }
122
123 /*
124 * Free a buffer lock.
125 */
126 #define BUF_LOCKFREE(bp) \
127 if (BUF_LOCKINUSE(bp)) \
128 panic("free locked buf")
129
130 static __inline void
bioq_init(struct bio_queue_head * bioq)131 bioq_init(struct bio_queue_head *bioq)
132 {
133 TAILQ_INIT(&bioq->queue);
134 bioq->off_unused = 0;
135 bioq->reorder = 0;
136 bioq->transition = NULL;
137 bioq->bio_unused = NULL;
138 }
139
140 static __inline void
bioq_insert_tail(struct bio_queue_head * bioq,struct bio * bio)141 bioq_insert_tail(struct bio_queue_head *bioq, struct bio *bio)
142 {
143 bioq->transition = NULL;
144 TAILQ_INSERT_TAIL(&bioq->queue, bio, bio_act);
145 }
146
147 static __inline void
bioq_remove(struct bio_queue_head * bioq,struct bio * bio)148 bioq_remove(struct bio_queue_head *bioq, struct bio *bio)
149 {
150 /*
151 * Adjust read insertion point when removing the bioq. The
152 * bio after the insert point is a write so move backwards
153 * one (NULL will indicate all the reads have cleared).
154 */
155 if (bio == bioq->transition)
156 bioq->transition = TAILQ_NEXT(bio, bio_act);
157 TAILQ_REMOVE(&bioq->queue, bio, bio_act);
158 }
159
160 static __inline struct bio *
bioq_first(struct bio_queue_head * bioq)161 bioq_first(struct bio_queue_head *bioq)
162 {
163 return (TAILQ_FIRST(&bioq->queue));
164 }
165
166 static __inline struct bio *
bioq_takefirst(struct bio_queue_head * bioq)167 bioq_takefirst(struct bio_queue_head *bioq)
168 {
169 struct bio *bp;
170
171 bp = TAILQ_FIRST(&bioq->queue);
172 if (bp != NULL)
173 bioq_remove(bioq, bp);
174 return (bp);
175 }
176
177 /*
178 * Adjust buffer cache buffer's activity count. This
179 * works similarly to vm_page->act_count.
180 */
181 static __inline void
buf_act_advance(struct buf * bp)182 buf_act_advance(struct buf *bp)
183 {
184 if (bp->b_act_count > ACT_MAX - ACT_ADVANCE)
185 bp->b_act_count = ACT_MAX;
186 else
187 bp->b_act_count += ACT_ADVANCE;
188 }
189
190 static __inline void
buf_act_decline(struct buf * bp)191 buf_act_decline(struct buf *bp)
192 {
193 if (bp->b_act_count < ACT_DECLINE)
194 bp->b_act_count = 0;
195 else
196 bp->b_act_count -= ACT_DECLINE;
197 }
198
199 /*
200 * biodeps inlines - used by softupdates and HAMMER.
201 *
202 * All bioops are MPSAFE
203 */
204 static __inline void
buf_dep_init(struct buf * bp)205 buf_dep_init(struct buf *bp)
206 {
207 bp->b_ops = NULL;
208 LIST_INIT(&bp->b_dep);
209 }
210
211 /*
212 * Precondition: the buffer has some dependencies.
213 *
214 * MPSAFE
215 */
216 static __inline void
buf_deallocate(struct buf * bp)217 buf_deallocate(struct buf *bp)
218 {
219 struct bio_ops *ops = bp->b_ops;
220
221 KKASSERT(! LIST_EMPTY(&bp->b_dep));
222 if (ops)
223 ops->io_deallocate(bp);
224 }
225
226 /*
227 * This callback is made from flushbufqueues() which uses BUF_LOCK().
228 * Since it isn't going through a normal buffer aquisition mechanic
229 * and calling the filesystem back enforce the vnode's KVABIO support.
230 */
231 static __inline int
buf_countdeps(struct buf * bp,int n)232 buf_countdeps(struct buf *bp, int n)
233 {
234 struct bio_ops *ops = bp->b_ops;
235 int r;
236
237 if (ops) {
238 if (bp->b_vp == NULL || (bp->b_vp->v_flag & VKVABIO) == 0)
239 bkvasync_all(bp);
240 r = ops->io_countdeps(bp, n);
241 } else {
242 r = 0;
243 }
244 return(r);
245 }
246
247 /*
248 * MPSAFE
249 */
250 static __inline void
buf_start(struct buf * bp)251 buf_start(struct buf *bp)
252 {
253 struct bio_ops *ops = bp->b_ops;
254
255 if (ops)
256 ops->io_start(bp);
257 }
258
259 /*
260 * MPSAFE
261 */
262 static __inline void
buf_complete(struct buf * bp)263 buf_complete(struct buf *bp)
264 {
265 struct bio_ops *ops = bp->b_ops;
266
267 if (ops)
268 ops->io_complete(bp);
269 }
270
271 /*
272 * MPSAFE
273 */
274 static __inline int
buf_fsync(struct vnode * vp)275 buf_fsync(struct vnode *vp)
276 {
277 struct bio_ops *ops = vp->v_mount->mnt_bioops;
278 int r;
279
280 if (ops)
281 r = ops->io_fsync(vp);
282 else
283 r = 0;
284 return(r);
285 }
286
287 /*
288 * MPSAFE
289 */
290 static __inline void
buf_movedeps(struct buf * bp1,struct buf * bp2)291 buf_movedeps(struct buf *bp1, struct buf *bp2)
292 {
293 struct bio_ops *ops = bp1->b_ops;
294
295 if (ops)
296 ops->io_movedeps(bp1, bp2);
297 }
298
299 /*
300 * MPSAFE
301 */
302 static __inline int
buf_checkread(struct buf * bp)303 buf_checkread(struct buf *bp)
304 {
305 struct bio_ops *ops = bp->b_ops;
306
307 if (ops)
308 return(ops->io_checkread(bp));
309 return(0);
310 }
311
312 /*
313 * This callback is made from flushbufqueues() which uses BUF_LOCK().
314 * Since it isn't going through a normal buffer aquisition mechanic
315 * and calling the filesystem back enforce the vnode's KVABIO support.
316 */
317 static __inline int
buf_checkwrite(struct buf * bp)318 buf_checkwrite(struct buf *bp)
319 {
320 struct bio_ops *ops = bp->b_ops;
321
322 if (ops) {
323 if (bp->b_vp == NULL || (bp->b_vp->v_flag & VKVABIO) == 0)
324 bkvasync_all(bp);
325 return(ops->io_checkwrite(bp));
326 }
327 return(0);
328 }
329
330 /*
331 * Chained biodone. The bio callback was made and the callback function
332 * wishes to chain the biodone. If no BIO's are left we call bpdone()
333 * with elseit=TRUE (asynchronous completion).
334 *
335 * MPSAFE
336 */
337 static __inline void
biodone_chain(struct bio * bio)338 biodone_chain(struct bio *bio)
339 {
340 if (bio->bio_prev)
341 biodone(bio->bio_prev);
342 else
343 bpdone(bio->bio_buf, 1);
344 }
345
346 static __inline int
bread(struct vnode * vp,off_t loffset,int size,struct buf ** bpp)347 bread(struct vnode *vp, off_t loffset, int size, struct buf **bpp)
348 {
349 *bpp = NULL;
350 return(breadnx(vp, loffset, size, B_NOTMETA,
351 NULL, NULL, 0, bpp));
352 }
353
354 static __inline int
bread_kvabio(struct vnode * vp,off_t loffset,int size,struct buf ** bpp)355 bread_kvabio(struct vnode *vp, off_t loffset, int size, struct buf **bpp)
356 {
357 *bpp = NULL;
358 return(breadnx(vp, loffset, size, B_NOTMETA | B_KVABIO,
359 NULL, NULL, 0, bpp));
360 }
361
362 static __inline int
breadn(struct vnode * vp,off_t loffset,int size,off_t * raoffset,int * rabsize,int cnt,struct buf ** bpp)363 breadn(struct vnode *vp, off_t loffset, int size, off_t *raoffset,
364 int *rabsize, int cnt, struct buf **bpp)
365 {
366 *bpp = NULL;
367 return(breadnx(vp, loffset, size, B_NOTMETA, raoffset,
368 rabsize, cnt, bpp));
369 }
370
371 static __inline int
cluster_read(struct vnode * vp,off_t filesize,off_t loffset,int blksize,size_t minreq,size_t maxreq,struct buf ** bpp)372 cluster_read(struct vnode *vp, off_t filesize, off_t loffset,
373 int blksize, size_t minreq, size_t maxreq, struct buf **bpp)
374 {
375 *bpp = NULL;
376 return(cluster_readx(vp, filesize, loffset, blksize, B_NOTMETA,
377 minreq, maxreq, bpp));
378 }
379
380 static __inline int
cluster_read_kvabio(struct vnode * vp,off_t filesize,off_t loffset,int blksize,size_t minreq,size_t maxreq,struct buf ** bpp)381 cluster_read_kvabio(struct vnode *vp, off_t filesize, off_t loffset,
382 int blksize, size_t minreq, size_t maxreq, struct buf **bpp)
383 {
384 *bpp = NULL;
385 return(cluster_readx(vp, filesize, loffset, blksize,
386 B_NOTMETA | B_KVABIO,
387 minreq, maxreq, bpp));
388 }
389
390 #endif /* _KERNEL */
391
392 #endif /* !_SYS_BUF2_H_ */
393