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9255a3b8 WJ |
1 | /* |
2 | * Copyright (c) 1989, 1990, 1991, 1992 William F. Jolitz, TeleMuse | |
3 | * All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * 3. All advertising materials mentioning features or use of this software | |
14 | * must display the following acknowledgement: | |
15 | * This software is a component of "386BSD" developed by | |
16 | William F. Jolitz, TeleMuse. | |
17 | * 4. Neither the name of the developer nor the name "386BSD" | |
18 | * may be used to endorse or promote products derived from this software | |
19 | * without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ | |
22 | * AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS | |
23 | * SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT. | |
24 | * THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT | |
25 | * NOT MAKE USE THIS WORK. | |
26 | * | |
27 | * FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED | |
28 | * BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN | |
29 | * REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES | |
30 | * (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING | |
31 | * JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND | |
32 | * LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE | |
33 | * ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS | |
34 | * OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992. | |
35 | * | |
36 | * THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``AS IS'' AND | |
37 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
38 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
39 | * ARE DISCLAIMED. IN NO EVENT SHALL THE DEVELOPER BE LIABLE | |
40 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
41 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
42 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
43 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
44 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
45 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
46 | * SUCH DAMAGE. | |
47 | * | |
48 | */ | |
49 | static char rcsid[] = "$Header: /usr/bill/working/sys/kern/RCS/vfs__bio.c,v 1.2 92/01/21 21:30:08 william Exp $"; | |
50 | ||
51 | #include "param.h" | |
52 | #include "proc.h" | |
53 | #include "vnode.h" | |
54 | #include "buf.h" | |
55 | #include "specdev.h" | |
56 | #include "mount.h" | |
57 | #include "malloc.h" | |
58 | #include "vm/vm.h" | |
59 | #include "resourcevar.h" | |
60 | ||
61 | struct buf *getnewbuf(int); | |
62 | extern vm_map_t buffer_map; | |
63 | ||
64 | /* | |
65 | * Initialize buffer headers and related structures. | |
66 | */ | |
67 | void bufinit() | |
68 | { | |
69 | struct bufhd *bh; | |
70 | struct buf *bp; | |
71 | ||
72 | /* first, make a null hash table */ | |
73 | for(bh = bufhash; bh < bufhash + BUFHSZ; bh++) { | |
74 | bh->b_flags = 0; | |
75 | bh->b_forw = (struct buf *)bh; | |
76 | bh->b_back = (struct buf *)bh; | |
77 | } | |
78 | ||
79 | /* next, make a null set of free lists */ | |
80 | for(bp = bfreelist; bp < bfreelist + BQUEUES; bp++) { | |
81 | bp->b_flags = 0; | |
82 | bp->av_forw = bp; | |
83 | bp->av_back = bp; | |
84 | bp->b_forw = bp; | |
85 | bp->b_back = bp; | |
86 | } | |
87 | ||
88 | /* finally, initialize each buffer header and stick on empty q */ | |
89 | for(bp = buf; bp < buf + nbuf ; bp++) { | |
90 | bp->b_flags = B_HEAD | B_INVAL; /* we're just an empty header */ | |
91 | bp->b_dev = NODEV; | |
92 | bp->b_vp = 0; | |
93 | binstailfree(bp, bfreelist + BQ_EMPTY); | |
94 | binshash(bp, bfreelist + BQ_EMPTY); | |
95 | } | |
96 | } | |
97 | ||
98 | /* | |
99 | * Find the block in the buffer pool. | |
100 | * If the buffer is not present, allocate a new buffer and load | |
101 | * its contents according to the filesystem fill routine. | |
102 | */ | |
103 | int | |
104 | bread(struct vnode *vp, daddr_t blkno, int size, struct ucred *cred, | |
105 | struct buf **bpp) | |
106 | { | |
107 | struct buf *bp; | |
108 | int rv = 0; | |
109 | ||
110 | bp = getblk (vp, blkno, size); | |
111 | ||
112 | /* if not found in cache, do some I/O */ | |
113 | if ((bp->b_flags & B_CACHE) == 0 || (bp->b_flags & B_INVAL) != 0) { | |
114 | bp->b_flags |= B_READ; | |
115 | bp->b_flags &= ~(B_DONE|B_ERROR|B_INVAL); | |
116 | bp->b_rcred = cred; | |
117 | VOP_STRATEGY(bp); | |
118 | rv = biowait (bp); | |
119 | } | |
120 | *bpp = bp; | |
121 | ||
122 | return (rv); | |
123 | } | |
124 | ||
125 | /* | |
126 | * Operates like bread, but also starts I/O on the specified | |
127 | * read-ahead block. [See page 55 of Bach's Book] | |
128 | */ | |
129 | int | |
130 | breada(struct vnode *vp, daddr_t blkno, int size, daddr_t rablkno, int rabsize, | |
131 | struct ucred *cred, struct buf **bpp) | |
132 | { | |
133 | struct buf *bp, *rabp; | |
134 | int rv = 0, needwait = 0; | |
135 | ||
136 | bp = getblk (vp, blkno, size); | |
137 | ||
138 | /* if not found in cache, do some I/O */ | |
139 | if ((bp->b_flags & B_CACHE) == 0 || (bp->b_flags & B_INVAL) != 0) { | |
140 | bp->b_flags |= B_READ; | |
141 | bp->b_flags &= ~(B_DONE|B_ERROR|B_INVAL); | |
142 | bp->b_rcred = cred; | |
143 | VOP_STRATEGY(bp); | |
144 | needwait++; | |
145 | } | |
146 | ||
147 | rabp = getblk (vp, rablkno, rabsize); | |
148 | ||
149 | /* if not found in cache, do some I/O (overlapped with first) */ | |
150 | if ((rabp->b_flags & B_CACHE) == 0 || (rabp->b_flags & B_INVAL) != 0) { | |
151 | rabp->b_flags |= B_READ | B_ASYNC; | |
152 | rabp->b_flags &= ~(B_DONE|B_ERROR|B_INVAL); | |
153 | rabp->b_rcred = cred; | |
154 | VOP_STRATEGY(rabp); | |
155 | } else | |
156 | brelse(rabp); | |
157 | ||
158 | /* wait for original I/O */ | |
159 | if (needwait) | |
160 | rv = biowait (bp); | |
161 | ||
162 | *bpp = bp; | |
163 | return (rv); | |
164 | } | |
165 | ||
166 | /* | |
167 | * Synchronous write. | |
168 | * Release buffer on completion. | |
169 | */ | |
170 | int | |
171 | bwrite(register struct buf *bp) | |
172 | { | |
173 | int rv; | |
174 | ||
175 | if(bp->b_flags & B_INVAL) { | |
176 | brelse(bp); | |
177 | return (0); | |
178 | } else { | |
179 | int wasdelayed; | |
180 | ||
181 | if(!(bp->b_flags & B_BUSY)) | |
182 | panic("bwrite: not busy"); | |
183 | ||
184 | wasdelayed = bp->b_flags & B_DELWRI; | |
185 | bp->b_flags &= ~(B_READ|B_DONE|B_ERROR|B_ASYNC|B_DELWRI); | |
186 | if(wasdelayed) | |
187 | reassignbuf(bp, bp->b_vp); | |
188 | ||
189 | bp->b_flags |= B_DIRTY; | |
190 | bp->b_vp->v_numoutput++; | |
191 | VOP_STRATEGY(bp); | |
192 | rv = biowait(bp); | |
193 | brelse(bp); | |
194 | return (rv); | |
195 | } | |
196 | } | |
197 | ||
198 | /* | |
199 | * Delayed write. | |
200 | * | |
201 | * The buffer is marked dirty, but is not queued for I/O. | |
202 | * This routine should be used when the buffer is expected | |
203 | * to be modified again soon, typically a small write that | |
204 | * partially fills a buffer. | |
205 | * | |
206 | * NB: magnetic tapes cannot be delayed; they must be | |
207 | * written in the order that the writes are requested. | |
208 | */ | |
209 | void | |
210 | bdwrite(register struct buf *bp) | |
211 | { | |
212 | ||
213 | if(!(bp->b_flags & B_BUSY)) | |
214 | panic("bdwrite: not busy"); | |
215 | ||
216 | if(bp->b_flags & B_INVAL) { | |
217 | brelse(bp); | |
218 | } | |
219 | if(bp->b_flags & B_TAPE) { | |
220 | bwrite(bp); | |
221 | return; | |
222 | } | |
223 | bp->b_flags &= ~(B_READ|B_DONE); | |
224 | bp->b_flags |= B_DIRTY|B_DELWRI; | |
225 | reassignbuf(bp, bp->b_vp); | |
226 | brelse(bp); | |
227 | return; | |
228 | } | |
229 | ||
230 | /* | |
231 | * Asynchronous write. | |
232 | * Start I/O on a buffer, but do not wait for it to complete. | |
233 | * The buffer is released when the I/O completes. | |
234 | */ | |
235 | void | |
236 | bawrite(register struct buf *bp) | |
237 | { | |
238 | ||
239 | if(!(bp->b_flags & B_BUSY)) | |
240 | panic("bawrite: not busy"); | |
241 | ||
242 | if(bp->b_flags & B_INVAL) | |
243 | brelse(bp); | |
244 | else { | |
245 | int wasdelayed; | |
246 | ||
247 | wasdelayed = bp->b_flags & B_DELWRI; | |
248 | bp->b_flags &= ~(B_READ|B_DONE|B_ERROR|B_DELWRI); | |
249 | if(wasdelayed) | |
250 | reassignbuf(bp, bp->b_vp); | |
251 | ||
252 | bp->b_flags |= B_DIRTY | B_ASYNC; | |
253 | bp->b_vp->v_numoutput++; | |
254 | VOP_STRATEGY(bp); | |
255 | } | |
256 | } | |
257 | ||
258 | /* | |
259 | * Release a buffer. | |
260 | * Even if the buffer is dirty, no I/O is started. | |
261 | */ | |
262 | void | |
263 | brelse(register struct buf *bp) | |
264 | { | |
265 | int x; | |
266 | ||
267 | /* anyone need a "free" block? */ | |
268 | x=splbio(); | |
269 | if ((bfreelist + BQ_AGE)->b_flags & B_WANTED) { | |
270 | (bfreelist + BQ_AGE) ->b_flags &= ~B_WANTED; | |
271 | wakeup(bfreelist); | |
272 | } | |
273 | /* anyone need this very block? */ | |
274 | if (bp->b_flags & B_WANTED) { | |
275 | bp->b_flags &= ~B_WANTED; | |
276 | wakeup(bp); | |
277 | } | |
278 | ||
279 | if (bp->b_flags & (B_INVAL|B_ERROR)) { | |
280 | bp->b_flags |= B_INVAL; | |
281 | bp->b_flags &= ~(B_DELWRI|B_CACHE); | |
282 | if(bp->b_vp) | |
283 | brelvp(bp); | |
284 | } | |
285 | ||
286 | /* enqueue */ | |
287 | /* just an empty buffer head ... */ | |
288 | /*if(bp->b_flags & B_HEAD) | |
289 | binsheadfree(bp, bfreelist + BQ_EMPTY)*/ | |
290 | /* buffers with junk contents */ | |
291 | /*else*/ if(bp->b_flags & (B_ERROR|B_INVAL|B_NOCACHE)) | |
292 | binsheadfree(bp, bfreelist + BQ_AGE) | |
293 | /* buffers with stale but valid contents */ | |
294 | else if(bp->b_flags & B_AGE) | |
295 | binstailfree(bp, bfreelist + BQ_AGE) | |
296 | /* buffers with valid and quite potentially reuseable contents */ | |
297 | else | |
298 | binstailfree(bp, bfreelist + BQ_LRU) | |
299 | ||
300 | /* unlock */ | |
301 | bp->b_flags &= ~B_BUSY; | |
302 | splx(x); | |
303 | ||
304 | } | |
305 | ||
306 | int freebufspace; | |
307 | int allocbufspace; | |
308 | ||
309 | /* | |
310 | * Find a buffer which is available for use. | |
311 | * If free memory for buffer space and an empty header from the empty list, | |
312 | * use that. Otherwise, select something from a free list. | |
313 | * Preference is to AGE list, then LRU list. | |
314 | */ | |
315 | static struct buf * | |
316 | getnewbuf(int sz) | |
317 | { | |
318 | struct buf *bp; | |
319 | int x; | |
320 | ||
321 | x = splbio(); | |
322 | start: | |
323 | /* can we constitute a new buffer? */ | |
324 | if (freebufspace > sz | |
325 | && bfreelist[BQ_EMPTY].av_forw != (struct buf *)bfreelist+BQ_EMPTY) { | |
326 | caddr_t addr; | |
327 | ||
328 | /*#define notyet*/ | |
329 | #ifndef notyet | |
330 | if ((addr = malloc (sz, M_TEMP, M_WAITOK)) == 0) goto tryfree; | |
331 | #else /* notyet */ | |
332 | /* get new memory buffer */ | |
333 | if (round_page(sz) == sz) | |
334 | addr = (caddr_t) kmem_alloc_wired_wait(buffer_map, sz); | |
335 | else | |
336 | addr = (caddr_t) malloc (sz, M_TEMP, M_WAITOK); | |
337 | /*if ((addr = malloc (sz, M_TEMP, M_NOWAIT)) == 0) goto tryfree;*/ | |
338 | bzero(addr, sz); | |
339 | #endif /* notyet */ | |
340 | freebufspace -= sz; | |
341 | allocbufspace += sz; | |
342 | ||
343 | bp = bfreelist[BQ_EMPTY].av_forw; | |
344 | bp->b_flags = B_BUSY | B_INVAL; | |
345 | bremfree(bp); | |
346 | bp->b_un.b_addr = addr; | |
347 | goto fillin; | |
348 | } | |
349 | ||
350 | tryfree: | |
351 | if (bfreelist[BQ_AGE].av_forw != (struct buf *)bfreelist+BQ_AGE) { | |
352 | bp = bfreelist[BQ_AGE].av_forw; | |
353 | bremfree(bp); | |
354 | } else if (bfreelist[BQ_LRU].av_forw != (struct buf *)bfreelist+BQ_LRU) { | |
355 | bp = bfreelist[BQ_LRU].av_forw; | |
356 | bremfree(bp); | |
357 | } else { | |
358 | /* wait for a free buffer of any kind */ | |
359 | (bfreelist + BQ_AGE)->b_flags |= B_WANTED; | |
360 | sleep(bfreelist, PRIBIO); | |
361 | splx(x); | |
362 | return (0); | |
363 | } | |
364 | ||
365 | /* if we are a delayed write, convert to an async write! */ | |
366 | if (bp->b_flags & B_DELWRI) { | |
367 | bp->b_flags |= B_BUSY; | |
368 | bawrite (bp); | |
369 | goto start; | |
370 | } | |
371 | ||
372 | ||
373 | if(bp->b_vp) | |
374 | brelvp(bp); | |
375 | ||
376 | /* we are not free, nor do we contain interesting data */ | |
377 | bp->b_flags = B_BUSY; | |
378 | fillin: | |
379 | bremhash(bp); | |
380 | splx(x); | |
381 | bp->b_dev = NODEV; | |
382 | bp->b_vp = NULL; | |
383 | bp->b_blkno = bp->b_lblkno = 0; | |
384 | bp->b_iodone = 0; | |
385 | bp->b_error = 0; | |
386 | bp->b_wcred = bp->b_rcred = NOCRED; | |
387 | if (bp->b_bufsize != sz) | |
388 | allocbuf(bp, sz); | |
389 | bp->b_bcount = bp->b_bufsize = sz; | |
390 | bp->b_dirtyoff = bp->b_dirtyend = 0; | |
391 | return (bp); | |
392 | } | |
393 | ||
394 | /* | |
395 | * Check to see if a block is currently memory resident. | |
396 | */ | |
397 | struct buf * | |
398 | incore(struct vnode *vp, daddr_t blkno) | |
399 | { | |
400 | struct buf *bh; | |
401 | struct buf *bp; | |
402 | ||
403 | bh = BUFHASH(vp, blkno); | |
404 | ||
405 | /* Search hash chain */ | |
406 | bp = bh->b_forw; | |
407 | while (bp != (struct buf *) bh) { | |
408 | /* hit */ | |
409 | if (bp->b_lblkno == blkno && bp->b_vp == vp | |
410 | && (bp->b_flags & B_INVAL) == 0) | |
411 | return (bp); | |
412 | bp = bp->b_forw; | |
413 | } | |
414 | ||
415 | return(0); | |
416 | } | |
417 | ||
418 | /* | |
419 | * Get a block of requested size that is associated with | |
420 | * a given vnode and block offset. If it is found in the | |
421 | * block cache, mark it as having been found, make it busy | |
422 | * and return it. Otherwise, return an empty block of the | |
423 | * correct size. It is up to the caller to insure that the | |
424 | * cached blocks be of the correct size. | |
425 | */ | |
426 | struct buf * | |
427 | getblk(register struct vnode *vp, daddr_t blkno, int size) | |
428 | { | |
429 | struct buf *bp, *bh; | |
430 | int x; | |
431 | ||
432 | for (;;) { | |
433 | if (bp = incore(vp, blkno)) { | |
434 | x = splbio(); | |
435 | if (bp->b_flags & B_BUSY) { | |
436 | bp->b_flags |= B_WANTED; | |
437 | sleep (bp, PRIBIO); | |
438 | splx(x); | |
439 | continue; | |
440 | } | |
441 | bp->b_flags |= B_BUSY | B_CACHE; | |
442 | bremfree(bp); | |
443 | if (size > bp->b_bufsize) | |
444 | panic("now what do we do?"); | |
445 | /* if (bp->b_bufsize != size) allocbuf(bp, size); */ | |
446 | } else { | |
447 | ||
448 | if((bp = getnewbuf(size)) == 0) continue; | |
449 | bp->b_blkno = bp->b_lblkno = blkno; | |
450 | bgetvp(vp, bp); | |
451 | x = splbio(); | |
452 | bh = BUFHASH(vp, blkno); | |
453 | binshash(bp, bh); | |
454 | bp->b_flags = B_BUSY; | |
455 | } | |
456 | splx(x); | |
457 | return (bp); | |
458 | } | |
459 | } | |
460 | ||
461 | /* | |
462 | * Get an empty, disassociated buffer of given size. | |
463 | */ | |
464 | struct buf * | |
465 | geteblk(int size) | |
466 | { | |
467 | struct buf *bp; | |
468 | int x; | |
469 | ||
470 | while ((bp = getnewbuf(size)) == 0) | |
471 | ; | |
472 | x = splbio(); | |
473 | binshash(bp, bfreelist + BQ_AGE); | |
474 | splx(x); | |
475 | ||
476 | return (bp); | |
477 | } | |
478 | ||
479 | /* | |
480 | * Exchange a buffer's underlying buffer storage for one of different | |
481 | * size, taking care to maintain contents appropriately. When buffer | |
482 | * increases in size, caller is responsible for filling out additional | |
483 | * contents. When buffer shrinks in size, data is lost, so caller must | |
484 | * first return it to backing store before shrinking the buffer, as | |
485 | * no implied I/O will be done. | |
486 | * | |
487 | * Expanded buffer is returned as value. | |
488 | */ | |
489 | void | |
490 | allocbuf(register struct buf *bp, int size) | |
491 | { | |
492 | caddr_t newcontents; | |
493 | ||
494 | /* get new memory buffer */ | |
495 | #ifndef notyet | |
496 | newcontents = (caddr_t) malloc (size, M_TEMP, M_WAITOK); | |
497 | #else /* notyet */ | |
498 | if (round_page(size) == size) | |
499 | newcontents = (caddr_t) kmem_alloc_wired_wait(buffer_map, size); | |
500 | else | |
501 | newcontents = (caddr_t) malloc (size, M_TEMP, M_WAITOK); | |
502 | #endif /* notyet */ | |
503 | ||
504 | /* copy the old into the new, up to the maximum that will fit */ | |
505 | bcopy (bp->b_un.b_addr, newcontents, min(bp->b_bufsize, size)); | |
506 | ||
507 | /* return old contents to free heap */ | |
508 | #ifndef notyet | |
509 | free (bp->b_un.b_addr, M_TEMP); | |
510 | #else /* notyet */ | |
511 | if (round_page(bp->b_bufsize) == bp->b_bufsize) | |
512 | kmem_free_wakeup(buffer_map, bp->b_un.b_addr, bp->b_bufsize); | |
513 | else | |
514 | free (bp->b_un.b_addr, M_TEMP); | |
515 | #endif /* notyet */ | |
516 | ||
517 | /* adjust buffer cache's idea of memory allocated to buffer contents */ | |
518 | freebufspace -= size - bp->b_bufsize; | |
519 | allocbufspace += size - bp->b_bufsize; | |
520 | ||
521 | /* update buffer header */ | |
522 | bp->b_un.b_addr = newcontents; | |
523 | bp->b_bcount = bp->b_bufsize = size; | |
524 | } | |
525 | ||
526 | /* | |
527 | * Patiently await operations to complete on this buffer. | |
528 | * When they do, extract error value and return it. | |
529 | * Extract and return any errors associated with the I/O. | |
530 | * If an invalid block, force it off the lookup hash chains. | |
531 | */ | |
532 | int | |
533 | biowait(register struct buf *bp) | |
534 | { | |
535 | int x; | |
536 | ||
537 | x = splbio(); | |
538 | while ((bp->b_flags & B_DONE) == 0) | |
539 | sleep((caddr_t)bp, PRIBIO); | |
540 | if((bp->b_flags & B_ERROR) || bp->b_error) { | |
541 | if ((bp->b_flags & B_INVAL) == 0) { | |
542 | bp->b_flags |= B_INVAL; | |
543 | bremhash(bp); | |
544 | binshash(bp, bfreelist + BQ_AGE); | |
545 | } | |
546 | if (!bp->b_error) | |
547 | bp->b_error = EIO; | |
548 | else | |
549 | bp->b_flags |= B_ERROR; | |
550 | splx(x); | |
551 | return (bp->b_error); | |
552 | } else { | |
553 | splx(x); | |
554 | return (0); | |
555 | } | |
556 | } | |
557 | ||
558 | /* | |
559 | * Finish up operations on a buffer, calling an optional | |
560 | * function (if requested), and releasing the buffer if | |
561 | * marked asynchronous. Then mark this buffer done so that | |
562 | * others biowait()'ing for it will notice when they are | |
563 | * woken up from sleep(). | |
564 | */ | |
565 | int | |
566 | biodone(register struct buf *bp) | |
567 | { | |
568 | int x; | |
569 | ||
570 | x = splbio(); | |
571 | if (bp->b_flags & B_CALL) (*bp->b_iodone)(bp); | |
572 | bp->b_flags &= ~B_CALL; | |
573 | if ((bp->b_flags & (B_READ|B_DIRTY)) == B_DIRTY) { | |
574 | bp->b_flags &= ~B_DIRTY; | |
575 | vwakeup(bp); | |
576 | } | |
577 | if (bp->b_flags & B_ASYNC) | |
578 | brelse(bp); | |
579 | bp->b_flags &= ~B_ASYNC; | |
580 | bp->b_flags |= B_DONE; | |
581 | wakeup(bp); | |
582 | splx(x); | |
583 | } |