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15637ed4 RG |
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 | * PATCHES MAGIC LEVEL PATCH THAT GOT US HERE | |
49 | * -------------------- ----- ---------------------- | |
50 | * CURRENT PATCH LEVEL: 2 00042 | |
51 | * -------------------- ----- ---------------------- | |
52 | * | |
53 | * 24 Apr 92 Martin Renters Fix NFS read request hang | |
54 | * 20 Aug 92 David Greenman Fix getnewbuf() 2xAllocation | |
55 | */ | |
2877196e | 56 | static char rcsid[] = "$Header: /a/cvs/386BSD/src/sys.386bsd/kern/vfs__bio.c,v 1.2 1993/07/18 11:27:45 paul Exp $"; |
15637ed4 RG |
57 | |
58 | #include "param.h" | |
59 | #include "proc.h" | |
60 | #include "vnode.h" | |
61 | #include "buf.h" | |
62 | #include "specdev.h" | |
63 | #include "mount.h" | |
64 | #include "malloc.h" | |
65 | #include "vm/vm.h" | |
66 | #include "resourcevar.h" | |
67 | ||
dbd7c74f | 68 | static struct buf *getnewbuf(int); |
15637ed4 RG |
69 | extern vm_map_t buffer_map; |
70 | ||
71 | /* | |
72 | * Initialize buffer headers and related structures. | |
73 | */ | |
74 | void bufinit() | |
75 | { | |
76 | struct bufhd *bh; | |
77 | struct buf *bp; | |
78 | ||
79 | /* first, make a null hash table */ | |
80 | for(bh = bufhash; bh < bufhash + BUFHSZ; bh++) { | |
81 | bh->b_flags = 0; | |
82 | bh->b_forw = (struct buf *)bh; | |
83 | bh->b_back = (struct buf *)bh; | |
84 | } | |
85 | ||
86 | /* next, make a null set of free lists */ | |
87 | for(bp = bfreelist; bp < bfreelist + BQUEUES; bp++) { | |
88 | bp->b_flags = 0; | |
89 | bp->av_forw = bp; | |
90 | bp->av_back = bp; | |
91 | bp->b_forw = bp; | |
92 | bp->b_back = bp; | |
93 | } | |
94 | ||
95 | /* finally, initialize each buffer header and stick on empty q */ | |
96 | for(bp = buf; bp < buf + nbuf ; bp++) { | |
97 | bp->b_flags = B_HEAD | B_INVAL; /* we're just an empty header */ | |
98 | bp->b_dev = NODEV; | |
99 | bp->b_vp = 0; | |
100 | binstailfree(bp, bfreelist + BQ_EMPTY); | |
101 | binshash(bp, bfreelist + BQ_EMPTY); | |
102 | } | |
103 | } | |
104 | ||
105 | /* | |
106 | * Find the block in the buffer pool. | |
107 | * If the buffer is not present, allocate a new buffer and load | |
108 | * its contents according to the filesystem fill routine. | |
109 | */ | |
110 | int | |
111 | bread(struct vnode *vp, daddr_t blkno, int size, struct ucred *cred, | |
112 | struct buf **bpp) | |
113 | { | |
114 | struct buf *bp; | |
115 | int rv = 0; | |
116 | ||
117 | bp = getblk (vp, blkno, size); | |
118 | ||
119 | /* if not found in cache, do some I/O */ | |
120 | if ((bp->b_flags & B_CACHE) == 0 || (bp->b_flags & B_INVAL) != 0) { | |
121 | bp->b_flags |= B_READ; | |
122 | bp->b_flags &= ~(B_DONE|B_ERROR|B_INVAL); | |
123 | if (cred != NOCRED) crhold(cred); /* 25 Apr 92*/ | |
124 | bp->b_rcred = cred; | |
125 | VOP_STRATEGY(bp); | |
126 | rv = biowait (bp); | |
127 | } | |
128 | *bpp = bp; | |
129 | ||
130 | return (rv); | |
131 | } | |
132 | ||
133 | /* | |
134 | * Operates like bread, but also starts I/O on the specified | |
135 | * read-ahead block. [See page 55 of Bach's Book] | |
136 | */ | |
137 | int | |
138 | breada(struct vnode *vp, daddr_t blkno, int size, daddr_t rablkno, int rabsize, | |
139 | struct ucred *cred, struct buf **bpp) | |
140 | { | |
141 | struct buf *bp, *rabp; | |
142 | int rv = 0, needwait = 0; | |
143 | ||
144 | bp = getblk (vp, blkno, size); | |
145 | ||
146 | /* if not found in cache, do some I/O */ | |
147 | if ((bp->b_flags & B_CACHE) == 0 || (bp->b_flags & B_INVAL) != 0) { | |
148 | bp->b_flags |= B_READ; | |
149 | bp->b_flags &= ~(B_DONE|B_ERROR|B_INVAL); | |
150 | if (cred != NOCRED) crhold(cred); /* 25 Apr 92*/ | |
151 | bp->b_rcred = cred; | |
152 | VOP_STRATEGY(bp); | |
153 | needwait++; | |
154 | } | |
155 | ||
156 | rabp = getblk (vp, rablkno, rabsize); | |
157 | ||
158 | /* if not found in cache, do some I/O (overlapped with first) */ | |
159 | if ((rabp->b_flags & B_CACHE) == 0 || (rabp->b_flags & B_INVAL) != 0) { | |
160 | rabp->b_flags |= B_READ | B_ASYNC; | |
161 | rabp->b_flags &= ~(B_DONE|B_ERROR|B_INVAL); | |
162 | if (cred != NOCRED) crhold(cred); /* 25 Apr 92*/ | |
163 | rabp->b_rcred = cred; | |
164 | VOP_STRATEGY(rabp); | |
165 | } else | |
166 | brelse(rabp); | |
167 | ||
168 | /* wait for original I/O */ | |
169 | if (needwait) | |
170 | rv = biowait (bp); | |
171 | ||
172 | *bpp = bp; | |
173 | return (rv); | |
174 | } | |
175 | ||
176 | /* | |
177 | * Synchronous write. | |
178 | * Release buffer on completion. | |
179 | */ | |
180 | int | |
181 | bwrite(register struct buf *bp) | |
182 | { | |
183 | int rv; | |
184 | ||
185 | if(bp->b_flags & B_INVAL) { | |
186 | brelse(bp); | |
187 | return (0); | |
188 | } else { | |
189 | int wasdelayed; | |
190 | ||
191 | if(!(bp->b_flags & B_BUSY)) | |
192 | panic("bwrite: not busy"); | |
193 | ||
194 | wasdelayed = bp->b_flags & B_DELWRI; | |
195 | bp->b_flags &= ~(B_READ|B_DONE|B_ERROR|B_ASYNC|B_DELWRI); | |
196 | if(wasdelayed) | |
197 | reassignbuf(bp, bp->b_vp); | |
198 | ||
199 | bp->b_flags |= B_DIRTY; | |
200 | bp->b_vp->v_numoutput++; | |
201 | VOP_STRATEGY(bp); | |
202 | rv = biowait(bp); | |
203 | brelse(bp); | |
204 | return (rv); | |
205 | } | |
206 | } | |
207 | ||
208 | /* | |
209 | * Delayed write. | |
210 | * | |
211 | * The buffer is marked dirty, but is not queued for I/O. | |
212 | * This routine should be used when the buffer is expected | |
213 | * to be modified again soon, typically a small write that | |
214 | * partially fills a buffer. | |
215 | * | |
216 | * NB: magnetic tapes cannot be delayed; they must be | |
217 | * written in the order that the writes are requested. | |
218 | */ | |
219 | void | |
220 | bdwrite(register struct buf *bp) | |
221 | { | |
222 | ||
223 | if(!(bp->b_flags & B_BUSY)) | |
224 | panic("bdwrite: not busy"); | |
225 | ||
226 | if(bp->b_flags & B_INVAL) { | |
227 | brelse(bp); | |
2877196e | 228 | return; |
15637ed4 RG |
229 | } |
230 | if(bp->b_flags & B_TAPE) { | |
231 | bwrite(bp); | |
232 | return; | |
233 | } | |
234 | bp->b_flags &= ~(B_READ|B_DONE); | |
235 | bp->b_flags |= B_DIRTY|B_DELWRI; | |
236 | reassignbuf(bp, bp->b_vp); | |
237 | brelse(bp); | |
238 | return; | |
239 | } | |
240 | ||
241 | /* | |
242 | * Asynchronous write. | |
243 | * Start I/O on a buffer, but do not wait for it to complete. | |
244 | * The buffer is released when the I/O completes. | |
245 | */ | |
246 | void | |
247 | bawrite(register struct buf *bp) | |
248 | { | |
249 | ||
250 | if(!(bp->b_flags & B_BUSY)) | |
251 | panic("bawrite: not busy"); | |
252 | ||
253 | if(bp->b_flags & B_INVAL) | |
254 | brelse(bp); | |
255 | else { | |
256 | int wasdelayed; | |
257 | ||
258 | wasdelayed = bp->b_flags & B_DELWRI; | |
259 | bp->b_flags &= ~(B_READ|B_DONE|B_ERROR|B_DELWRI); | |
260 | if(wasdelayed) | |
261 | reassignbuf(bp, bp->b_vp); | |
262 | ||
263 | bp->b_flags |= B_DIRTY | B_ASYNC; | |
264 | bp->b_vp->v_numoutput++; | |
265 | VOP_STRATEGY(bp); | |
266 | } | |
267 | } | |
268 | ||
269 | /* | |
270 | * Release a buffer. | |
271 | * Even if the buffer is dirty, no I/O is started. | |
272 | */ | |
273 | void | |
274 | brelse(register struct buf *bp) | |
275 | { | |
276 | int x; | |
277 | ||
278 | /* anyone need a "free" block? */ | |
279 | x=splbio(); | |
280 | if ((bfreelist + BQ_AGE)->b_flags & B_WANTED) { | |
281 | (bfreelist + BQ_AGE) ->b_flags &= ~B_WANTED; | |
282 | wakeup(bfreelist); | |
283 | } | |
284 | /* anyone need this very block? */ | |
285 | if (bp->b_flags & B_WANTED) { | |
286 | bp->b_flags &= ~B_WANTED; | |
287 | wakeup(bp); | |
288 | } | |
289 | ||
290 | if (bp->b_flags & (B_INVAL|B_ERROR)) { | |
291 | bp->b_flags |= B_INVAL; | |
292 | bp->b_flags &= ~(B_DELWRI|B_CACHE); | |
293 | if(bp->b_vp) | |
294 | brelvp(bp); | |
295 | } | |
296 | ||
297 | /* enqueue */ | |
298 | /* just an empty buffer head ... */ | |
299 | /*if(bp->b_flags & B_HEAD) | |
300 | binsheadfree(bp, bfreelist + BQ_EMPTY)*/ | |
301 | /* buffers with junk contents */ | |
302 | /*else*/ if(bp->b_flags & (B_ERROR|B_INVAL|B_NOCACHE)) | |
303 | binsheadfree(bp, bfreelist + BQ_AGE) | |
304 | /* buffers with stale but valid contents */ | |
305 | else if(bp->b_flags & B_AGE) | |
306 | binstailfree(bp, bfreelist + BQ_AGE) | |
307 | /* buffers with valid and quite potentially reuseable contents */ | |
308 | else | |
309 | binstailfree(bp, bfreelist + BQ_LRU) | |
310 | ||
311 | /* unlock */ | |
312 | bp->b_flags &= ~B_BUSY; | |
313 | splx(x); | |
314 | ||
315 | } | |
316 | ||
317 | int freebufspace; | |
318 | int allocbufspace; | |
319 | ||
320 | /* | |
321 | * Find a buffer which is available for use. | |
322 | * If free memory for buffer space and an empty header from the empty list, | |
323 | * use that. Otherwise, select something from a free list. | |
324 | * Preference is to AGE list, then LRU list. | |
325 | */ | |
326 | static struct buf * | |
327 | getnewbuf(int sz) | |
328 | { | |
329 | struct buf *bp; | |
330 | int x; | |
331 | ||
332 | x = splbio(); | |
333 | start: | |
334 | /* can we constitute a new buffer? */ | |
335 | if (freebufspace > sz | |
336 | && bfreelist[BQ_EMPTY].av_forw != (struct buf *)bfreelist+BQ_EMPTY) { | |
337 | caddr_t addr; | |
338 | ||
339 | /*#define notyet*/ | |
340 | #ifndef notyet | |
341 | if ((addr = malloc (sz, M_TEMP, M_WAITOK)) == 0) goto tryfree; | |
342 | #else /* notyet */ | |
343 | /* get new memory buffer */ | |
344 | if (round_page(sz) == sz) | |
345 | addr = (caddr_t) kmem_alloc_wired_wait(buffer_map, sz); | |
346 | else | |
347 | addr = (caddr_t) malloc (sz, M_TEMP, M_WAITOK); | |
348 | /*if ((addr = malloc (sz, M_TEMP, M_NOWAIT)) == 0) goto tryfree;*/ | |
349 | bzero(addr, sz); | |
350 | #endif /* notyet */ | |
351 | freebufspace -= sz; | |
352 | allocbufspace += sz; | |
353 | ||
354 | bp = bfreelist[BQ_EMPTY].av_forw; | |
355 | bp->b_flags = B_BUSY | B_INVAL; | |
356 | bremfree(bp); | |
357 | bp->b_un.b_addr = addr; | |
358 | bp->b_bufsize = sz; /* 20 Aug 92*/ | |
359 | goto fillin; | |
360 | } | |
361 | ||
362 | tryfree: | |
363 | if (bfreelist[BQ_AGE].av_forw != (struct buf *)bfreelist+BQ_AGE) { | |
364 | bp = bfreelist[BQ_AGE].av_forw; | |
365 | bremfree(bp); | |
366 | } else if (bfreelist[BQ_LRU].av_forw != (struct buf *)bfreelist+BQ_LRU) { | |
367 | bp = bfreelist[BQ_LRU].av_forw; | |
368 | bremfree(bp); | |
369 | } else { | |
370 | /* wait for a free buffer of any kind */ | |
371 | (bfreelist + BQ_AGE)->b_flags |= B_WANTED; | |
372 | sleep(bfreelist, PRIBIO); | |
373 | splx(x); | |
374 | return (0); | |
375 | } | |
376 | ||
377 | /* if we are a delayed write, convert to an async write! */ | |
378 | if (bp->b_flags & B_DELWRI) { | |
379 | bp->b_flags |= B_BUSY; | |
380 | bawrite (bp); | |
381 | goto start; | |
382 | } | |
383 | ||
384 | ||
385 | if(bp->b_vp) | |
386 | brelvp(bp); | |
387 | ||
388 | /* we are not free, nor do we contain interesting data */ | |
389 | if (bp->b_rcred != NOCRED) crfree(bp->b_rcred); /* 25 Apr 92*/ | |
390 | if (bp->b_wcred != NOCRED) crfree(bp->b_wcred); | |
391 | bp->b_flags = B_BUSY; | |
392 | fillin: | |
393 | bremhash(bp); | |
394 | splx(x); | |
395 | bp->b_dev = NODEV; | |
396 | bp->b_vp = NULL; | |
397 | bp->b_blkno = bp->b_lblkno = 0; | |
398 | bp->b_iodone = 0; | |
399 | bp->b_error = 0; | |
400 | bp->b_wcred = bp->b_rcred = NOCRED; | |
401 | if (bp->b_bufsize != sz) | |
402 | allocbuf(bp, sz); | |
403 | bp->b_bcount = bp->b_bufsize = sz; | |
404 | bp->b_dirtyoff = bp->b_dirtyend = 0; | |
405 | return (bp); | |
406 | } | |
407 | ||
408 | /* | |
409 | * Check to see if a block is currently memory resident. | |
410 | */ | |
411 | struct buf * | |
412 | incore(struct vnode *vp, daddr_t blkno) | |
413 | { | |
414 | struct buf *bh; | |
415 | struct buf *bp; | |
416 | ||
417 | bh = BUFHASH(vp, blkno); | |
418 | ||
419 | /* Search hash chain */ | |
420 | bp = bh->b_forw; | |
421 | while (bp != (struct buf *) bh) { | |
422 | /* hit */ | |
423 | if (bp->b_lblkno == blkno && bp->b_vp == vp | |
424 | && (bp->b_flags & B_INVAL) == 0) | |
425 | return (bp); | |
426 | bp = bp->b_forw; | |
427 | } | |
428 | ||
429 | return(0); | |
430 | } | |
431 | ||
432 | /* | |
433 | * Get a block of requested size that is associated with | |
434 | * a given vnode and block offset. If it is found in the | |
435 | * block cache, mark it as having been found, make it busy | |
436 | * and return it. Otherwise, return an empty block of the | |
437 | * correct size. It is up to the caller to insure that the | |
438 | * cached blocks be of the correct size. | |
439 | */ | |
440 | struct buf * | |
441 | getblk(register struct vnode *vp, daddr_t blkno, int size) | |
442 | { | |
443 | struct buf *bp, *bh; | |
444 | int x; | |
445 | ||
446 | for (;;) { | |
447 | if (bp = incore(vp, blkno)) { | |
448 | x = splbio(); | |
449 | if (bp->b_flags & B_BUSY) { | |
450 | bp->b_flags |= B_WANTED; | |
451 | sleep (bp, PRIBIO); | |
452 | splx(x); | |
453 | continue; | |
454 | } | |
455 | bp->b_flags |= B_BUSY | B_CACHE; | |
456 | bremfree(bp); | |
457 | if (size > bp->b_bufsize) | |
458 | panic("now what do we do?"); | |
459 | /* if (bp->b_bufsize != size) allocbuf(bp, size); */ | |
460 | } else { | |
461 | ||
462 | if((bp = getnewbuf(size)) == 0) continue; | |
463 | bp->b_blkno = bp->b_lblkno = blkno; | |
464 | bgetvp(vp, bp); | |
465 | x = splbio(); | |
466 | bh = BUFHASH(vp, blkno); | |
467 | binshash(bp, bh); | |
468 | bp->b_flags = B_BUSY; | |
469 | } | |
470 | splx(x); | |
471 | return (bp); | |
472 | } | |
473 | } | |
474 | ||
475 | /* | |
476 | * Get an empty, disassociated buffer of given size. | |
477 | */ | |
478 | struct buf * | |
479 | geteblk(int size) | |
480 | { | |
481 | struct buf *bp; | |
482 | int x; | |
483 | ||
484 | while ((bp = getnewbuf(size)) == 0) | |
485 | ; | |
486 | x = splbio(); | |
487 | binshash(bp, bfreelist + BQ_AGE); | |
488 | splx(x); | |
489 | ||
490 | return (bp); | |
491 | } | |
492 | ||
493 | /* | |
494 | * Exchange a buffer's underlying buffer storage for one of different | |
495 | * size, taking care to maintain contents appropriately. When buffer | |
496 | * increases in size, caller is responsible for filling out additional | |
497 | * contents. When buffer shrinks in size, data is lost, so caller must | |
498 | * first return it to backing store before shrinking the buffer, as | |
499 | * no implied I/O will be done. | |
500 | * | |
501 | * Expanded buffer is returned as value. | |
502 | */ | |
503 | void | |
504 | allocbuf(register struct buf *bp, int size) | |
505 | { | |
506 | caddr_t newcontents; | |
507 | ||
508 | /* get new memory buffer */ | |
509 | #ifndef notyet | |
510 | newcontents = (caddr_t) malloc (size, M_TEMP, M_WAITOK); | |
511 | #else /* notyet */ | |
512 | if (round_page(size) == size) | |
513 | newcontents = (caddr_t) kmem_alloc_wired_wait(buffer_map, size); | |
514 | else | |
515 | newcontents = (caddr_t) malloc (size, M_TEMP, M_WAITOK); | |
516 | #endif /* notyet */ | |
517 | ||
518 | /* copy the old into the new, up to the maximum that will fit */ | |
519 | bcopy (bp->b_un.b_addr, newcontents, min(bp->b_bufsize, size)); | |
520 | ||
521 | /* return old contents to free heap */ | |
522 | #ifndef notyet | |
523 | free (bp->b_un.b_addr, M_TEMP); | |
524 | #else /* notyet */ | |
525 | if (round_page(bp->b_bufsize) == bp->b_bufsize) | |
526 | kmem_free_wakeup(buffer_map, bp->b_un.b_addr, bp->b_bufsize); | |
527 | else | |
528 | free (bp->b_un.b_addr, M_TEMP); | |
529 | #endif /* notyet */ | |
530 | ||
531 | /* adjust buffer cache's idea of memory allocated to buffer contents */ | |
532 | freebufspace -= size - bp->b_bufsize; | |
533 | allocbufspace += size - bp->b_bufsize; | |
534 | ||
535 | /* update buffer header */ | |
536 | bp->b_un.b_addr = newcontents; | |
537 | bp->b_bcount = bp->b_bufsize = size; | |
538 | } | |
539 | ||
540 | /* | |
541 | * Patiently await operations to complete on this buffer. | |
542 | * When they do, extract error value and return it. | |
543 | * Extract and return any errors associated with the I/O. | |
544 | * If an invalid block, force it off the lookup hash chains. | |
545 | */ | |
546 | int | |
547 | biowait(register struct buf *bp) | |
548 | { | |
549 | int x; | |
550 | ||
551 | x = splbio(); | |
552 | while ((bp->b_flags & B_DONE) == 0) | |
553 | sleep((caddr_t)bp, PRIBIO); | |
554 | if((bp->b_flags & B_ERROR) || bp->b_error) { | |
555 | if ((bp->b_flags & B_INVAL) == 0) { | |
556 | bp->b_flags |= B_INVAL; | |
557 | bremhash(bp); | |
558 | binshash(bp, bfreelist + BQ_AGE); | |
559 | } | |
560 | if (!bp->b_error) | |
561 | bp->b_error = EIO; | |
562 | else | |
563 | bp->b_flags |= B_ERROR; | |
564 | splx(x); | |
565 | return (bp->b_error); | |
566 | } else { | |
567 | splx(x); | |
568 | return (0); | |
569 | } | |
570 | } | |
571 | ||
572 | /* | |
573 | * Finish up operations on a buffer, calling an optional | |
574 | * function (if requested), and releasing the buffer if | |
575 | * marked asynchronous. Then mark this buffer done so that | |
576 | * others biowait()'ing for it will notice when they are | |
577 | * woken up from sleep(). | |
578 | */ | |
579 | int | |
580 | biodone(register struct buf *bp) | |
581 | { | |
582 | int x; | |
583 | ||
584 | x = splbio(); | |
585 | if (bp->b_flags & B_CALL) (*bp->b_iodone)(bp); | |
586 | bp->b_flags &= ~B_CALL; | |
587 | if ((bp->b_flags & (B_READ|B_DIRTY)) == B_DIRTY) { | |
588 | bp->b_flags &= ~B_DIRTY; | |
589 | vwakeup(bp); | |
590 | } | |
591 | if (bp->b_flags & B_ASYNC) | |
592 | brelse(bp); | |
593 | bp->b_flags &= ~B_ASYNC; | |
594 | bp->b_flags |= B_DONE; | |
595 | wakeup(bp); | |
596 | splx(x); | |
597 | } |