1 /*-
2 * Copyright (c) 1993
3 * The Regents of the University of California. All rights reserved.
4 * Modifications/enhancements:
5 * Copyright (c) 1995 John S. Dyson. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94
36 * $FreeBSD: releng/5.1/sys/kern/vfs_cluster.c 115365 2003-05-28 13:22:10Z iedowse $
37 */
38
39 #include "opt_debug_cluster.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/kernel.h>
44 #include <sys/proc.h>
45 #include <sys/bio.h>
46 #include <sys/buf.h>
47 #include <sys/vnode.h>
48 #include <sys/malloc.h>
49 #include <sys/mount.h>
50 #include <sys/resourcevar.h>
51 #include <sys/vmmeter.h>
52 #include <vm/vm.h>
53 #include <vm/vm_object.h>
54 #include <vm/vm_page.h>
55 #include <sys/sysctl.h>
56
57 #if defined(CLUSTERDEBUG)
58 static int rcluster= 0;
59 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0,
60 "Debug VFS clustering code");
61 #endif
62
63 static MALLOC_DEFINE(M_SEGMENT, "cluster_save buffer", "cluster_save buffer");
64
65 static struct cluster_save *
66 cluster_collectbufs(struct vnode *vp, struct buf *last_bp);
67 static struct buf *
68 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn,
69 daddr_t blkno, long size, int run, struct buf *fbp);
70
71 static int write_behind = 1;
72 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0,
73 "Cluster write-behind; 0: disable, 1: enable, 2: backed off");
74
75 static int read_max = 8;
76 SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0,
77 "Cluster read-ahead max block count");
78
79 /* Page expended to mark partially backed buffers */
80 extern vm_page_t bogus_page;
81
82 /*
83 * Number of physical bufs (pbufs) this subsystem is allowed.
84 * Manipulated by vm_pager.c
85 */
86 extern int cluster_pbuf_freecnt;
87
88 /*
89 * Read data to a buf, including read-ahead if we find this to be beneficial.
90 * cluster_read replaces bread.
91 */
92 int
93 cluster_read(vp, filesize, lblkno, size, cred, totread, seqcount, bpp)
94 struct vnode *vp;
95 u_quad_t filesize;
96 daddr_t lblkno;
97 long size;
98 struct ucred *cred;
99 long totread;
100 int seqcount;
101 struct buf **bpp;
102 {
103 struct buf *bp, *rbp, *reqbp;
104 daddr_t blkno, origblkno;
105 int maxra, racluster;
106 int error, ncontig;
107 int i;
108
109 error = 0;
110
111 /*
112 * Try to limit the amount of read-ahead by a few
113 * ad-hoc parameters. This needs work!!!
114 */
115 racluster = vp->v_mount->mnt_iosize_max / size;
116 maxra = seqcount;
117 maxra = min(read_max, maxra);
118 maxra = min(nbuf/8, maxra);
119 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize)
120 maxra = (filesize / size) - lblkno;
121
122 /*
123 * get the requested block
124 */
125 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, 0);
126 origblkno = lblkno;
127
128 /*
129 * if it is in the cache, then check to see if the reads have been
130 * sequential. If they have, then try some read-ahead, otherwise
131 * back-off on prospective read-aheads.
132 */
133 if (bp->b_flags & B_CACHE) {
134 if (!seqcount) {
135 return 0;
136 } else if ((bp->b_flags & B_RAM) == 0) {
137 return 0;
138 } else {
139 int s;
140 bp->b_flags &= ~B_RAM;
141 /*
142 * We do the spl here so that there is no window
143 * between the incore and the b_usecount increment
144 * below. We opt to keep the spl out of the loop
145 * for efficiency.
146 */
147 s = splbio();
148 VI_LOCK(vp);
149 for (i = 1; i < maxra; i++) {
150 /*
151 * Stop if the buffer does not exist or it
152 * is invalid (about to go away?)
153 */
154 rbp = gbincore(vp, lblkno+i);
155 if (rbp == NULL || (rbp->b_flags & B_INVAL))
156 break;
157
158 /*
159 * Set another read-ahead mark so we know
160 * to check again.
161 */
162 if (((i % racluster) == (racluster - 1)) ||
163 (i == (maxra - 1)))
164 rbp->b_flags |= B_RAM;
165 }
166 VI_UNLOCK(vp);
167 splx(s);
168 if (i >= maxra) {
169 return 0;
170 }
171 lblkno += i;
172 }
173 reqbp = bp = NULL;
174 /*
175 * If it isn't in the cache, then get a chunk from
176 * disk if sequential, otherwise just get the block.
177 */
178 } else {
179 off_t firstread = bp->b_offset;
180 int nblks;
181
182 KASSERT(bp->b_offset != NOOFFSET,
183 ("cluster_read: no buffer offset"));
184
185 ncontig = 0;
186
187 /*
188 * Compute the total number of blocks that we should read
189 * synchronously.
190 */
191 if (firstread + totread > filesize)
192 totread = filesize - firstread;
193 nblks = howmany(totread, size);
194 if (nblks > racluster)
195 nblks = racluster;
196
197 /*
198 * Now compute the number of contiguous blocks.
199 */
200 if (nblks > 1) {
201 error = VOP_BMAP(vp, lblkno, NULL,
202 &blkno, &ncontig, NULL);
203 /*
204 * If this failed to map just do the original block.
205 */
206 if (error || blkno == -1)
207 ncontig = 0;
208 }
209
210 /*
211 * If we have contiguous data available do a cluster
212 * otherwise just read the requested block.
213 */
214 if (ncontig) {
215 /* Account for our first block. */
216 ncontig = min(ncontig + 1, nblks);
217 if (ncontig < nblks)
218 nblks = ncontig;
219 bp = cluster_rbuild(vp, filesize, lblkno,
220 blkno, size, nblks, bp);
221 lblkno += (bp->b_bufsize / size);
222 } else {
223 bp->b_flags |= B_RAM;
224 bp->b_iocmd = BIO_READ;
225 lblkno += 1;
226 }
227 }
228
229 /*
230 * handle the synchronous read so that it is available ASAP.
231 */
232 if (bp) {
233 if ((bp->b_flags & B_CLUSTER) == 0) {
234 vfs_busy_pages(bp, 0);
235 }
236 bp->b_flags &= ~B_INVAL;
237 bp->b_ioflags &= ~BIO_ERROR;
238 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL)
239 BUF_KERNPROC(bp);
240 error = VOP_STRATEGY(vp, bp);
241 curproc->p_stats->p_ru.ru_inblock++;
242 if (error)
243 return (error);
244 }
245
246 /*
247 * If we have been doing sequential I/O, then do some read-ahead.
248 */
249 while (lblkno < (origblkno + maxra)) {
250 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL);
251 if (error)
252 break;
253
254 if (blkno == -1)
255 break;
256
257 /*
258 * We could throttle ncontig here by maxra but we might as
259 * well read the data if it is contiguous. We're throttled
260 * by racluster anyway.
261 */
262 if (ncontig) {
263 ncontig = min(ncontig + 1, racluster);
264 rbp = cluster_rbuild(vp, filesize, lblkno, blkno,
265 size, ncontig, NULL);
266 lblkno += (rbp->b_bufsize / size);
267 if (rbp->b_flags & B_DELWRI) {
268 bqrelse(rbp);
269 continue;
270 }
271 } else {
272 rbp = getblk(vp, lblkno, size, 0, 0, 0);
273 lblkno += 1;
274 if (rbp->b_flags & B_DELWRI) {
275 bqrelse(rbp);
276 continue;
277 }
278 rbp->b_flags |= B_ASYNC | B_RAM;
279 rbp->b_iocmd = BIO_READ;
280 rbp->b_blkno = blkno;
281 }
282 if (rbp->b_flags & B_CACHE) {
283 rbp->b_flags &= ~B_ASYNC;
284 bqrelse(rbp);
285 continue;
286 }
287 if ((rbp->b_flags & B_CLUSTER) == 0) {
288 vfs_busy_pages(rbp, 0);
289 }
290 rbp->b_flags &= ~B_INVAL;
291 rbp->b_ioflags &= ~BIO_ERROR;
292 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL)
293 BUF_KERNPROC(rbp);
294 (void) VOP_STRATEGY(vp, rbp);
295 curproc->p_stats->p_ru.ru_inblock++;
296 }
297
298 if (reqbp)
299 return (bufwait(reqbp));
300 else
301 return (error);
302 }
303
304 /*
305 * If blocks are contiguous on disk, use this to provide clustered
306 * read ahead. We will read as many blocks as possible sequentially
307 * and then parcel them up into logical blocks in the buffer hash table.
308 */
309 static struct buf *
310 cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp)
311 struct vnode *vp;
312 u_quad_t filesize;
313 daddr_t lbn;
314 daddr_t blkno;
315 long size;
316 int run;
317 struct buf *fbp;
318 {
319 struct buf *bp, *tbp;
320 daddr_t bn;
321 int i, inc, j;
322
323 GIANT_REQUIRED;
324
325 KASSERT(size == vp->v_mount->mnt_stat.f_iosize,
326 ("cluster_rbuild: size %ld != filesize %ld\n",
327 size, vp->v_mount->mnt_stat.f_iosize));
328
329 /*
330 * avoid a division
331 */
332 while ((u_quad_t) size * (lbn + run) > filesize) {
333 --run;
334 }
335
336 if (fbp) {
337 tbp = fbp;
338 tbp->b_iocmd = BIO_READ;
339 } else {
340 tbp = getblk(vp, lbn, size, 0, 0, 0);
341 if (tbp->b_flags & B_CACHE)
342 return tbp;
343 tbp->b_flags |= B_ASYNC | B_RAM;
344 tbp->b_iocmd = BIO_READ;
345 }
346
347 tbp->b_blkno = blkno;
348 if( (tbp->b_flags & B_MALLOC) ||
349 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) )
350 return tbp;
351
352 bp = trypbuf(&cluster_pbuf_freecnt);
353 if (bp == 0)
354 return tbp;
355
356 /*
357 * We are synthesizing a buffer out of vm_page_t's, but
358 * if the block size is not page aligned then the starting
359 * address may not be either. Inherit the b_data offset
360 * from the original buffer.
361 */
362 bp->b_data = (char *)((vm_offset_t)bp->b_data |
363 ((vm_offset_t)tbp->b_data & PAGE_MASK));
364 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO;
365 bp->b_iocmd = BIO_READ;
366 bp->b_iodone = cluster_callback;
367 bp->b_blkno = blkno;
368 bp->b_lblkno = lbn;
369 bp->b_offset = tbp->b_offset;
370 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset"));
371 pbgetvp(vp, bp);
372
373 TAILQ_INIT(&bp->b_cluster.cluster_head);
374
375 bp->b_bcount = 0;
376 bp->b_bufsize = 0;
377 bp->b_npages = 0;
378
379 inc = btodb(size);
380 for (bn = blkno, i = 0; i < run; ++i, bn += inc) {
381 if (i != 0) {
382 if ((bp->b_npages * PAGE_SIZE) +
383 round_page(size) > vp->v_mount->mnt_iosize_max) {
384 break;
385 }
386
387 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT);
388
389 /* Don't wait around for locked bufs. */
390 if (tbp == NULL)
391 break;
392
393 /*
394 * Stop scanning if the buffer is fully valid
395 * (marked B_CACHE), or locked (may be doing a
396 * background write), or if the buffer is not
397 * VMIO backed. The clustering code can only deal
398 * with VMIO-backed buffers.
399 */
400 if ((tbp->b_flags & (B_CACHE|B_LOCKED)) ||
401 (tbp->b_flags & B_VMIO) == 0) {
402 bqrelse(tbp);
403 break;
404 }
405
406 /*
407 * The buffer must be completely invalid in order to
408 * take part in the cluster. If it is partially valid
409 * then we stop.
410 */
411 for (j = 0;j < tbp->b_npages; j++) {
412 if (tbp->b_pages[j]->valid)
413 break;
414 }
415 if (j != tbp->b_npages) {
416 bqrelse(tbp);
417 break;
418 }
419
420 /*
421 * Set a read-ahead mark as appropriate
422 */
423 if ((fbp && (i == 1)) || (i == (run - 1)))
424 tbp->b_flags |= B_RAM;
425
426 /*
427 * Set the buffer up for an async read (XXX should
428 * we do this only if we do not wind up brelse()ing?).
429 * Set the block number if it isn't set, otherwise
430 * if it is make sure it matches the block number we
431 * expect.
432 */
433 tbp->b_flags |= B_ASYNC;
434 tbp->b_iocmd = BIO_READ;
435 if (tbp->b_blkno == tbp->b_lblkno) {
436 tbp->b_blkno = bn;
437 } else if (tbp->b_blkno != bn) {
438 brelse(tbp);
439 break;
440 }
441 }
442 /*
443 * XXX fbp from caller may not be B_ASYNC, but we are going
444 * to biodone() it in cluster_callback() anyway
445 */
446 BUF_KERNPROC(tbp);
447 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
448 tbp, b_cluster.cluster_entry);
449 if (tbp->b_object != NULL)
450 VM_OBJECT_LOCK(tbp->b_object);
451 vm_page_lock_queues();
452 for (j = 0; j < tbp->b_npages; j += 1) {
453 vm_page_t m;
454 m = tbp->b_pages[j];
455 vm_page_io_start(m);
456 vm_object_pip_add(m->object, 1);
457 if ((bp->b_npages == 0) ||
458 (bp->b_pages[bp->b_npages-1] != m)) {
459 bp->b_pages[bp->b_npages] = m;
460 bp->b_npages++;
461 }
462 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL)
463 tbp->b_pages[j] = bogus_page;
464 }
465 vm_page_unlock_queues();
466 if (tbp->b_object != NULL)
467 VM_OBJECT_UNLOCK(tbp->b_object);
468 /*
469 * XXX shouldn't this be += size for both, like in
470 * cluster_wbuild()?
471 *
472 * Don't inherit tbp->b_bufsize as it may be larger due to
473 * a non-page-aligned size. Instead just aggregate using
474 * 'size'.
475 */
476 if (tbp->b_bcount != size)
477 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size);
478 if (tbp->b_bufsize != size)
479 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size);
480 bp->b_bcount += size;
481 bp->b_bufsize += size;
482 }
483
484 /*
485 * Fully valid pages in the cluster are already good and do not need
486 * to be re-read from disk. Replace the page with bogus_page
487 */
488 for (j = 0; j < bp->b_npages; j++) {
489 if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) ==
490 VM_PAGE_BITS_ALL) {
491 bp->b_pages[j] = bogus_page;
492 }
493 }
494 if (bp->b_bufsize > bp->b_kvasize)
495 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
496 bp->b_bufsize, bp->b_kvasize);
497 bp->b_kvasize = bp->b_bufsize;
498
499 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
500 (vm_page_t *)bp->b_pages, bp->b_npages);
501 return (bp);
502 }
503
504 /*
505 * Cleanup after a clustered read or write.
506 * This is complicated by the fact that any of the buffers might have
507 * extra memory (if there were no empty buffer headers at allocbuf time)
508 * that we will need to shift around.
509 */
510 void
511 cluster_callback(bp)
512 struct buf *bp;
513 {
514 struct buf *nbp, *tbp;
515 int error = 0;
516
517 GIANT_REQUIRED;
518
519 /*
520 * Must propogate errors to all the components.
521 */
522 if (bp->b_ioflags & BIO_ERROR)
523 error = bp->b_error;
524
525 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages);
526 /*
527 * Move memory from the large cluster buffer into the component
528 * buffers and mark IO as done on these.
529 */
530 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head);
531 tbp; tbp = nbp) {
532 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry);
533 if (error) {
534 tbp->b_ioflags |= BIO_ERROR;
535 tbp->b_error = error;
536 } else {
537 tbp->b_dirtyoff = tbp->b_dirtyend = 0;
538 tbp->b_flags &= ~B_INVAL;
539 tbp->b_ioflags &= ~BIO_ERROR;
540 /*
541 * XXX the bdwrite()/bqrelse() issued during
542 * cluster building clears B_RELBUF (see bqrelse()
543 * comment). If direct I/O was specified, we have
544 * to restore it here to allow the buffer and VM
545 * to be freed.
546 */
547 if (tbp->b_flags & B_DIRECT)
548 tbp->b_flags |= B_RELBUF;
549 }
550 bufdone(tbp);
551 }
552 relpbuf(bp, &cluster_pbuf_freecnt);
553 }
554
555 /*
556 * cluster_wbuild_wb:
557 *
558 * Implement modified write build for cluster.
559 *
560 * write_behind = 0 write behind disabled
561 * write_behind = 1 write behind normal (default)
562 * write_behind = 2 write behind backed-off
563 */
564
565 static __inline int
566 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len)
567 {
568 int r = 0;
569
570 switch(write_behind) {
571 case 2:
572 if (start_lbn < len)
573 break;
574 start_lbn -= len;
575 /* FALLTHROUGH */
576 case 1:
577 r = cluster_wbuild(vp, size, start_lbn, len);
578 /* FALLTHROUGH */
579 default:
580 /* FALLTHROUGH */
581 break;
582 }
583 return(r);
584 }
585
586 /*
587 * Do clustered write for FFS.
588 *
589 * Three cases:
590 * 1. Write is not sequential (write asynchronously)
591 * Write is sequential:
592 * 2. beginning of cluster - begin cluster
593 * 3. middle of a cluster - add to cluster
594 * 4. end of a cluster - asynchronously write cluster
595 */
596 void
597 cluster_write(bp, filesize, seqcount)
598 struct buf *bp;
599 u_quad_t filesize;
600 int seqcount;
601 {
602 struct vnode *vp;
603 daddr_t lbn;
604 int maxclen, cursize;
605 int lblocksize;
606 int async;
607
608 vp = bp->b_vp;
609 if (vp->v_type == VREG) {
610 async = vp->v_mount->mnt_flag & MNT_ASYNC;
611 lblocksize = vp->v_mount->mnt_stat.f_iosize;
612 } else {
613 async = 0;
614 lblocksize = bp->b_bufsize;
615 }
616 lbn = bp->b_lblkno;
617 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset"));
618
619 /* Initialize vnode to beginning of file. */
620 if (lbn == 0)
621 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
622
623 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 ||
624 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) {
625 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1;
626 if (vp->v_clen != 0) {
627 /*
628 * Next block is not sequential.
629 *
630 * If we are not writing at end of file, the process
631 * seeked to another point in the file since its last
632 * write, or we have reached our maximum cluster size,
633 * then push the previous cluster. Otherwise try
634 * reallocating to make it sequential.
635 *
636 * Change to algorithm: only push previous cluster if
637 * it was sequential from the point of view of the
638 * seqcount heuristic, otherwise leave the buffer
639 * intact so we can potentially optimize the I/O
640 * later on in the buf_daemon or update daemon
641 * flush.
642 */
643 cursize = vp->v_lastw - vp->v_cstart + 1;
644 if (((u_quad_t) bp->b_offset + lblocksize) != filesize ||
645 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) {
646 if (!async && seqcount > 0) {
647 cluster_wbuild_wb(vp, lblocksize,
648 vp->v_cstart, cursize);
649 }
650 } else {
651 struct buf **bpp, **endbp;
652 struct cluster_save *buflist;
653
654 buflist = cluster_collectbufs(vp, bp);
655 endbp = &buflist->bs_children
656 [buflist->bs_nchildren - 1];
657 if (VOP_REALLOCBLKS(vp, buflist)) {
658 /*
659 * Failed, push the previous cluster
660 * if *really* writing sequentially
661 * in the logical file (seqcount > 1),
662 * otherwise delay it in the hopes that
663 * the low level disk driver can
664 * optimize the write ordering.
665 */
666 for (bpp = buflist->bs_children;
667 bpp < endbp; bpp++)
668 brelse(*bpp);
669 free(buflist, M_SEGMENT);
670 if (seqcount > 1) {
671 cluster_wbuild_wb(vp,
672 lblocksize, vp->v_cstart,
673 cursize);
674 }
675 } else {
676 /*
677 * Succeeded, keep building cluster.
678 */
679 for (bpp = buflist->bs_children;
680 bpp <= endbp; bpp++)
681 bdwrite(*bpp);
682 free(buflist, M_SEGMENT);
683 vp->v_lastw = lbn;
684 vp->v_lasta = bp->b_blkno;
685 return;
686 }
687 }
688 }
689 /*
690 * Consider beginning a cluster. If at end of file, make
691 * cluster as large as possible, otherwise find size of
692 * existing cluster.
693 */
694 if ((vp->v_type == VREG) &&
695 ((u_quad_t) bp->b_offset + lblocksize) != filesize &&
696 (bp->b_blkno == bp->b_lblkno) &&
697 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) ||
698 bp->b_blkno == -1)) {
699 bawrite(bp);
700 vp->v_clen = 0;
701 vp->v_lasta = bp->b_blkno;
702 vp->v_cstart = lbn + 1;
703 vp->v_lastw = lbn;
704 return;
705 }
706 vp->v_clen = maxclen;
707 if (!async && maxclen == 0) { /* I/O not contiguous */
708 vp->v_cstart = lbn + 1;
709 bawrite(bp);
710 } else { /* Wait for rest of cluster */
711 vp->v_cstart = lbn;
712 bdwrite(bp);
713 }
714 } else if (lbn == vp->v_cstart + vp->v_clen) {
715 /*
716 * At end of cluster, write it out if seqcount tells us we
717 * are operating sequentially, otherwise let the buf or
718 * update daemon handle it.
719 */
720 bdwrite(bp);
721 if (seqcount > 1)
722 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1);
723 vp->v_clen = 0;
724 vp->v_cstart = lbn + 1;
725 } else if (vm_page_count_severe()) {
726 /*
727 * We are low on memory, get it going NOW
728 */
729 bawrite(bp);
730 } else {
731 /*
732 * In the middle of a cluster, so just delay the I/O for now.
733 */
734 bdwrite(bp);
735 }
736 vp->v_lastw = lbn;
737 vp->v_lasta = bp->b_blkno;
738 }
739
740
741 /*
742 * This is an awful lot like cluster_rbuild...wish they could be combined.
743 * The last lbn argument is the current block on which I/O is being
744 * performed. Check to see that it doesn't fall in the middle of
745 * the current block (if last_bp == NULL).
746 */
747 int
748 cluster_wbuild(vp, size, start_lbn, len)
749 struct vnode *vp;
750 long size;
751 daddr_t start_lbn;
752 int len;
753 {
754 struct buf *bp, *tbp;
755 int i, j, s;
756 int totalwritten = 0;
757 int dbsize = btodb(size);
758
759 GIANT_REQUIRED;
760
761 while (len > 0) {
762 s = splbio();
763 /*
764 * If the buffer is not delayed-write (i.e. dirty), or it
765 * is delayed-write but either locked or inval, it cannot
766 * partake in the clustered write.
767 */
768 VI_LOCK(vp);
769 if ((tbp = gbincore(vp, start_lbn)) == NULL) {
770 VI_UNLOCK(vp);
771 ++start_lbn;
772 --len;
773 splx(s);
774 continue;
775 }
776 if (BUF_LOCK(tbp,
777 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, VI_MTX(vp))) {
778 ++start_lbn;
779 --len;
780 splx(s);
781 continue;
782 }
783 if ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) !=
784 B_DELWRI) {
785 BUF_UNLOCK(tbp);
786 ++start_lbn;
787 --len;
788 splx(s);
789 continue;
790 }
791 bremfree(tbp);
792 tbp->b_flags &= ~B_DONE;
793 splx(s);
794
795 /*
796 * Extra memory in the buffer, punt on this buffer.
797 * XXX we could handle this in most cases, but we would
798 * have to push the extra memory down to after our max
799 * possible cluster size and then potentially pull it back
800 * up if the cluster was terminated prematurely--too much
801 * hassle.
802 */
803 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) !=
804 (B_CLUSTEROK | B_VMIO)) ||
805 (tbp->b_bcount != tbp->b_bufsize) ||
806 (tbp->b_bcount != size) ||
807 (len == 1) ||
808 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) {
809 totalwritten += tbp->b_bufsize;
810 bawrite(tbp);
811 ++start_lbn;
812 --len;
813 continue;
814 }
815
816 /*
817 * We got a pbuf to make the cluster in.
818 * so initialise it.
819 */
820 TAILQ_INIT(&bp->b_cluster.cluster_head);
821 bp->b_bcount = 0;
822 bp->b_magic = tbp->b_magic;
823 bp->b_op = tbp->b_op;
824 bp->b_bufsize = 0;
825 bp->b_npages = 0;
826 if (tbp->b_wcred != NOCRED)
827 bp->b_wcred = crhold(tbp->b_wcred);
828
829 bp->b_blkno = tbp->b_blkno;
830 bp->b_lblkno = tbp->b_lblkno;
831 bp->b_offset = tbp->b_offset;
832
833 /*
834 * We are synthesizing a buffer out of vm_page_t's, but
835 * if the block size is not page aligned then the starting
836 * address may not be either. Inherit the b_data offset
837 * from the original buffer.
838 */
839 bp->b_data = (char *)((vm_offset_t)bp->b_data |
840 ((vm_offset_t)tbp->b_data & PAGE_MASK));
841 bp->b_flags |= B_CLUSTER |
842 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT | B_NOWDRAIN));
843 bp->b_iodone = cluster_callback;
844 pbgetvp(vp, bp);
845 /*
846 * From this location in the file, scan forward to see
847 * if there are buffers with adjacent data that need to
848 * be written as well.
849 */
850 for (i = 0; i < len; ++i, ++start_lbn) {
851 if (i != 0) { /* If not the first buffer */
852 s = splbio();
853 /*
854 * If the adjacent data is not even in core it
855 * can't need to be written.
856 */
857 VI_LOCK(vp);
858 if ((tbp = gbincore(vp, start_lbn)) == NULL) {
859 VI_UNLOCK(vp);
860 splx(s);
861 break;
862 }
863
864 /*
865 * If it IS in core, but has different
866 * characteristics, or is locked (which
867 * means it could be undergoing a background
868 * I/O or be in a weird state), then don't
869 * cluster with it.
870 */
871 if (BUF_LOCK(tbp,
872 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK,
873 VI_MTX(vp))) {
874 splx(s);
875 break;
876 }
877
878 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK |
879 B_INVAL | B_DELWRI | B_NEEDCOMMIT))
880 != (B_DELWRI | B_CLUSTEROK |
881 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) ||
882 (tbp->b_flags & B_LOCKED) ||
883 tbp->b_wcred != bp->b_wcred) {
884 BUF_UNLOCK(tbp);
885 splx(s);
886 break;
887 }
888
889 /*
890 * Check that the combined cluster
891 * would make sense with regard to pages
892 * and would not be too large
893 */
894 if ((tbp->b_bcount != size) ||
895 ((bp->b_blkno + (dbsize * i)) !=
896 tbp->b_blkno) ||
897 ((tbp->b_npages + bp->b_npages) >
898 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) {
899 BUF_UNLOCK(tbp);
900 splx(s);
901 break;
902 }
903 /*
904 * Ok, it's passed all the tests,
905 * so remove it from the free list
906 * and mark it busy. We will use it.
907 */
908 bremfree(tbp);
909 tbp->b_flags &= ~B_DONE;
910 splx(s);
911 } /* end of code for non-first buffers only */
912 /* check for latent dependencies to be handled */
913 if ((LIST_FIRST(&tbp->b_dep)) != NULL) {
914 tbp->b_iocmd = BIO_WRITE;
915 buf_start(tbp);
916 }
917 /*
918 * If the IO is via the VM then we do some
919 * special VM hackery (yuck). Since the buffer's
920 * block size may not be page-aligned it is possible
921 * for a page to be shared between two buffers. We
922 * have to get rid of the duplication when building
923 * the cluster.
924 */
925 if (tbp->b_flags & B_VMIO) {
926 vm_page_t m;
927
928 if (i != 0) { /* if not first buffer */
929 for (j = 0; j < tbp->b_npages; j += 1) {
930 m = tbp->b_pages[j];
931 if (m->flags & PG_BUSY) {
932 bqrelse(tbp);
933 goto finishcluster;
934 }
935 }
936 }
937 if (tbp->b_object != NULL)
938 VM_OBJECT_LOCK(tbp->b_object);
939 vm_page_lock_queues();
940 for (j = 0; j < tbp->b_npages; j += 1) {
941 m = tbp->b_pages[j];
942 vm_page_io_start(m);
943 vm_object_pip_add(m->object, 1);
944 if ((bp->b_npages == 0) ||
945 (bp->b_pages[bp->b_npages - 1] != m)) {
946 bp->b_pages[bp->b_npages] = m;
947 bp->b_npages++;
948 }
949 }
950 vm_page_unlock_queues();
951 if (tbp->b_object != NULL)
952 VM_OBJECT_UNLOCK(tbp->b_object);
953 }
954 bp->b_bcount += size;
955 bp->b_bufsize += size;
956
957 s = splbio();
958 bundirty(tbp);
959 tbp->b_flags &= ~B_DONE;
960 tbp->b_ioflags &= ~BIO_ERROR;
961 tbp->b_flags |= B_ASYNC;
962 tbp->b_iocmd = BIO_WRITE;
963 reassignbuf(tbp, tbp->b_vp); /* put on clean list */
964 VI_LOCK(tbp->b_vp);
965 ++tbp->b_vp->v_numoutput;
966 VI_UNLOCK(tbp->b_vp);
967 splx(s);
968 BUF_KERNPROC(tbp);
969 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
970 tbp, b_cluster.cluster_entry);
971 }
972 finishcluster:
973 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
974 (vm_page_t *) bp->b_pages, bp->b_npages);
975 if (bp->b_bufsize > bp->b_kvasize)
976 panic(
977 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
978 bp->b_bufsize, bp->b_kvasize);
979 bp->b_kvasize = bp->b_bufsize;
980 totalwritten += bp->b_bufsize;
981 bp->b_dirtyoff = 0;
982 bp->b_dirtyend = bp->b_bufsize;
983 bawrite(bp);
984
985 len -= i;
986 }
987 return totalwritten;
988 }
989
990 /*
991 * Collect together all the buffers in a cluster.
992 * Plus add one additional buffer.
993 */
994 static struct cluster_save *
995 cluster_collectbufs(vp, last_bp)
996 struct vnode *vp;
997 struct buf *last_bp;
998 {
999 struct cluster_save *buflist;
1000 struct buf *bp;
1001 daddr_t lbn;
1002 int i, len;
1003
1004 len = vp->v_lastw - vp->v_cstart + 1;
1005 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
1006 M_SEGMENT, M_WAITOK);
1007 buflist->bs_nchildren = 0;
1008 buflist->bs_children = (struct buf **) (buflist + 1);
1009 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) {
1010 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp);
1011 buflist->bs_children[i] = bp;
1012 if (bp->b_blkno == bp->b_lblkno)
1013 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno,
1014 NULL, NULL);
1015 }
1016 buflist->bs_children[i] = bp = last_bp;
1017 if (bp->b_blkno == bp->b_lblkno)
1018 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno,
1019 NULL, NULL);
1020 buflist->bs_nchildren = i + 1;
1021 return (buflist);
1022 }
Cache object: e2d20ae8724d3e4bf75b7d1fa51fa7b2
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