Initial import from FreeBSD RELENG_4:
[dragonfly.git] / sys / kern / vfs_cluster.c
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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: src/sys/kern/vfs_cluster.c,v 1.92.2.9 2001/11/18 07:10:59 dillon Exp $
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/buf.h>
46#include <sys/vnode.h>
47#include <sys/malloc.h>
48#include <sys/mount.h>
49#include <sys/resourcevar.h>
50#include <sys/vmmeter.h>
51#include <vm/vm.h>
52#include <vm/vm_object.h>
53#include <vm/vm_page.h>
54#include <sys/sysctl.h>
55
56#if defined(CLUSTERDEBUG)
57#include <sys/sysctl.h>
58static int rcluster= 0;
59SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, "");
60#endif
61
62static MALLOC_DEFINE(M_SEGMENT, "cluster_save buffer", "cluster_save buffer");
63
64static struct cluster_save *
65 cluster_collectbufs __P((struct vnode *vp, struct buf *last_bp));
66static struct buf *
67 cluster_rbuild __P((struct vnode *vp, u_quad_t filesize, daddr_t lbn,
68 daddr_t blkno, long size, int run, struct buf *fbp));
69
70static int write_behind = 1;
71SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, "");
72
73extern vm_page_t bogus_page;
74
75extern int cluster_pbuf_freecnt;
76
77/*
78 * Maximum number of blocks for read-ahead.
79 */
80#define MAXRA 32
81
82/*
83 * This replaces bread.
84 */
85int
86cluster_read(vp, filesize, lblkno, size, cred, totread, seqcount, bpp)
87 struct vnode *vp;
88 u_quad_t filesize;
89 daddr_t lblkno;
90 long size;
91 struct ucred *cred;
92 long totread;
93 int seqcount;
94 struct buf **bpp;
95{
96 struct buf *bp, *rbp, *reqbp;
97 daddr_t blkno, origblkno;
98 int error, num_ra;
99 int i;
100 int maxra, racluster;
101 long origtotread;
102
103 error = 0;
104
105 /*
106 * Try to limit the amount of read-ahead by a few
107 * ad-hoc parameters. This needs work!!!
108 */
109 racluster = vp->v_mount->mnt_iosize_max / size;
110 maxra = 2 * racluster + (totread / size);
111 if (maxra > MAXRA)
112 maxra = MAXRA;
113 if (maxra > nbuf/8)
114 maxra = nbuf/8;
115
116 /*
117 * get the requested block
118 */
119 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0);
120 origblkno = lblkno;
121 origtotread = totread;
122
123 /*
124 * if it is in the cache, then check to see if the reads have been
125 * sequential. If they have, then try some read-ahead, otherwise
126 * back-off on prospective read-aheads.
127 */
128 if (bp->b_flags & B_CACHE) {
129 if (!seqcount) {
130 return 0;
131 } else if ((bp->b_flags & B_RAM) == 0) {
132 return 0;
133 } else {
134 int s;
135 struct buf *tbp;
136 bp->b_flags &= ~B_RAM;
137 /*
138 * We do the spl here so that there is no window
139 * between the incore and the b_usecount increment
140 * below. We opt to keep the spl out of the loop
141 * for efficiency.
142 */
143 s = splbio();
144 for (i = 1; i < maxra; i++) {
145
146 if (!(tbp = incore(vp, lblkno+i))) {
147 break;
148 }
149
150 /*
151 * Set another read-ahead mark so we know
152 * to check again.
153 */
154 if (((i % racluster) == (racluster - 1)) ||
155 (i == (maxra - 1)))
156 tbp->b_flags |= B_RAM;
157 }
158 splx(s);
159 if (i >= maxra) {
160 return 0;
161 }
162 lblkno += i;
163 }
164 reqbp = bp = NULL;
165 } else {
166 off_t firstread = bp->b_offset;
167
168 KASSERT(bp->b_offset != NOOFFSET,
169 ("cluster_read: no buffer offset"));
170 if (firstread + totread > filesize)
171 totread = filesize - firstread;
172 if (totread > size) {
173 int nblks = 0;
174 int ncontigafter;
175 while (totread > 0) {
176 nblks++;
177 totread -= size;
178 }
179 if (nblks == 1)
180 goto single_block_read;
181 if (nblks > racluster)
182 nblks = racluster;
183
184 error = VOP_BMAP(vp, lblkno, NULL,
185 &blkno, &ncontigafter, NULL);
186 if (error)
187 goto single_block_read;
188 if (blkno == -1)
189 goto single_block_read;
190 if (ncontigafter == 0)
191 goto single_block_read;
192 if (ncontigafter + 1 < nblks)
193 nblks = ncontigafter + 1;
194
195 bp = cluster_rbuild(vp, filesize, lblkno,
196 blkno, size, nblks, bp);
197 lblkno += (bp->b_bufsize / size);
198 } else {
199single_block_read:
200 /*
201 * if it isn't in the cache, then get a chunk from
202 * disk if sequential, otherwise just get the block.
203 */
204 bp->b_flags |= B_READ | B_RAM;
205 lblkno += 1;
206 }
207 }
208
209 /*
210 * if we have been doing sequential I/O, then do some read-ahead
211 */
212 rbp = NULL;
213 if (seqcount && (lblkno < (origblkno + seqcount))) {
214 /*
215 * we now build the read-ahead buffer if it is desirable.
216 */
217 if (((u_quad_t)(lblkno + 1) * size) <= filesize &&
218 !(error = VOP_BMAP(vp, lblkno, NULL, &blkno, &num_ra, NULL)) &&
219 blkno != -1) {
220 int nblksread;
221 int ntoread = num_ra + 1;
222 nblksread = (origtotread + size - 1) / size;
223 if (seqcount < nblksread)
224 seqcount = nblksread;
225 if (seqcount < ntoread)
226 ntoread = seqcount;
227 if (num_ra) {
228 rbp = cluster_rbuild(vp, filesize, lblkno,
229 blkno, size, ntoread, NULL);
230 } else {
231 rbp = getblk(vp, lblkno, size, 0, 0);
232 rbp->b_flags |= B_READ | B_ASYNC | B_RAM;
233 rbp->b_blkno = blkno;
234 }
235 }
236 }
237
238 /*
239 * handle the synchronous read
240 */
241 if (bp) {
242#if defined(CLUSTERDEBUG)
243 if (rcluster)
244 printf("S(%ld,%ld,%d) ",
245 (long)bp->b_lblkno, bp->b_bcount, seqcount);
246#endif
247 if ((bp->b_flags & B_CLUSTER) == 0) {
248 vfs_busy_pages(bp, 0);
249 }
250 bp->b_flags &= ~(B_ERROR|B_INVAL);
251 if (bp->b_flags & (B_ASYNC|B_CALL))
252 BUF_KERNPROC(bp);
253 error = VOP_STRATEGY(vp, bp);
254 curproc->p_stats->p_ru.ru_inblock++;
255 }
256
257 /*
258 * and if we have read-aheads, do them too
259 */
260 if (rbp) {
261 if (error) {
262 rbp->b_flags &= ~(B_ASYNC | B_READ);
263 brelse(rbp);
264 } else if (rbp->b_flags & B_CACHE) {
265 rbp->b_flags &= ~(B_ASYNC | B_READ);
266 bqrelse(rbp);
267 } else {
268#if defined(CLUSTERDEBUG)
269 if (rcluster) {
270 if (bp)
271 printf("A+(%ld,%ld,%ld,%d) ",
272 (long)rbp->b_lblkno, rbp->b_bcount,
273 (long)(rbp->b_lblkno - origblkno),
274 seqcount);
275 else
276 printf("A(%ld,%ld,%ld,%d) ",
277 (long)rbp->b_lblkno, rbp->b_bcount,
278 (long)(rbp->b_lblkno - origblkno),
279 seqcount);
280 }
281#endif
282
283 if ((rbp->b_flags & B_CLUSTER) == 0) {
284 vfs_busy_pages(rbp, 0);
285 }
286 rbp->b_flags &= ~(B_ERROR|B_INVAL);
287 if (rbp->b_flags & (B_ASYNC|B_CALL))
288 BUF_KERNPROC(rbp);
289 (void) VOP_STRATEGY(vp, rbp);
290 curproc->p_stats->p_ru.ru_inblock++;
291 }
292 }
293 if (reqbp)
294 return (biowait(reqbp));
295 else
296 return (error);
297}
298
299/*
300 * If blocks are contiguous on disk, use this to provide clustered
301 * read ahead. We will read as many blocks as possible sequentially
302 * and then parcel them up into logical blocks in the buffer hash table.
303 */
304static struct buf *
305cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp)
306 struct vnode *vp;
307 u_quad_t filesize;
308 daddr_t lbn;
309 daddr_t blkno;
310 long size;
311 int run;
312 struct buf *fbp;
313{
314 struct buf *bp, *tbp;
315 daddr_t bn;
316 int i, inc, j;
317
318 KASSERT(size == vp->v_mount->mnt_stat.f_iosize,
319 ("cluster_rbuild: size %ld != filesize %ld\n",
320 size, vp->v_mount->mnt_stat.f_iosize));
321
322 /*
323 * avoid a division
324 */
325 while ((u_quad_t) size * (lbn + run) > filesize) {
326 --run;
327 }
328
329 if (fbp) {
330 tbp = fbp;
331 tbp->b_flags |= B_READ;
332 } else {
333 tbp = getblk(vp, lbn, size, 0, 0);
334 if (tbp->b_flags & B_CACHE)
335 return tbp;
336 tbp->b_flags |= B_ASYNC | B_READ | B_RAM;
337 }
338
339 tbp->b_blkno = blkno;
340 if( (tbp->b_flags & B_MALLOC) ||
341 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) )
342 return tbp;
343
344 bp = trypbuf(&cluster_pbuf_freecnt);
345 if (bp == 0)
346 return tbp;
347
348 /*
349 * We are synthesizing a buffer out of vm_page_t's, but
350 * if the block size is not page aligned then the starting
351 * address may not be either. Inherit the b_data offset
352 * from the original buffer.
353 */
354 bp->b_data = (char *)((vm_offset_t)bp->b_data |
355 ((vm_offset_t)tbp->b_data & PAGE_MASK));
356 bp->b_flags = B_ASYNC | B_READ | B_CALL | B_CLUSTER | B_VMIO;
357 bp->b_iodone = cluster_callback;
358 bp->b_blkno = blkno;
359 bp->b_lblkno = lbn;
360 bp->b_offset = tbp->b_offset;
361 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset"));
362 pbgetvp(vp, bp);
363
364 TAILQ_INIT(&bp->b_cluster.cluster_head);
365
366 bp->b_bcount = 0;
367 bp->b_bufsize = 0;
368 bp->b_npages = 0;
369
370 inc = btodb(size);
371 for (bn = blkno, i = 0; i < run; ++i, bn += inc) {
372 if (i != 0) {
373 if ((bp->b_npages * PAGE_SIZE) +
374 round_page(size) > vp->v_mount->mnt_iosize_max) {
375 break;
376 }
377
378 /*
379 * Shortcut some checks and try to avoid buffers that
380 * would block in the lock. The same checks have to
381 * be made again after we officially get the buffer.
382 */
383 if ((tbp = incore(vp, lbn + i)) != NULL) {
384 if (BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT))
385 break;
386 BUF_UNLOCK(tbp);
387
388 for (j = 0; j < tbp->b_npages; j++) {
389 if (tbp->b_pages[j]->valid)
390 break;
391 }
392
393 if (j != tbp->b_npages)
394 break;
395
396 if (tbp->b_bcount != size)
397 break;
398 }
399
400 tbp = getblk(vp, lbn + i, size, 0, 0);
401
402 /*
403 * Stop scanning if the buffer is fuly valid
404 * (marked B_CACHE), or locked (may be doing a
405 * background write), or if the buffer is not
406 * VMIO backed. The clustering code can only deal
407 * with VMIO-backed buffers.
408 */
409 if ((tbp->b_flags & (B_CACHE|B_LOCKED)) ||
410 (tbp->b_flags & B_VMIO) == 0) {
411 bqrelse(tbp);
412 break;
413 }
414
415 /*
416 * The buffer must be completely invalid in order to
417 * take part in the cluster. If it is partially valid
418 * then we stop.
419 */
420 for (j = 0;j < tbp->b_npages; j++) {
421 if (tbp->b_pages[j]->valid)
422 break;
423 }
424 if (j != tbp->b_npages) {
425 bqrelse(tbp);
426 break;
427 }
428
429 /*
430 * Set a read-ahead mark as appropriate
431 */
432 if ((fbp && (i == 1)) || (i == (run - 1)))
433 tbp->b_flags |= B_RAM;
434
435 /*
436 * Set the buffer up for an async read (XXX should
437 * we do this only if we do not wind up brelse()ing?).
438 * Set the block number if it isn't set, otherwise
439 * if it is make sure it matches the block number we
440 * expect.
441 */
442 tbp->b_flags |= B_READ | B_ASYNC;
443 if (tbp->b_blkno == tbp->b_lblkno) {
444 tbp->b_blkno = bn;
445 } else if (tbp->b_blkno != bn) {
446 brelse(tbp);
447 break;
448 }
449 }
450 /*
451 * XXX fbp from caller may not be B_ASYNC, but we are going
452 * to biodone() it in cluster_callback() anyway
453 */
454 BUF_KERNPROC(tbp);
455 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
456 tbp, b_cluster.cluster_entry);
457 for (j = 0; j < tbp->b_npages; j += 1) {
458 vm_page_t m;
459 m = tbp->b_pages[j];
460 vm_page_io_start(m);
461 vm_object_pip_add(m->object, 1);
462 if ((bp->b_npages == 0) ||
463 (bp->b_pages[bp->b_npages-1] != m)) {
464 bp->b_pages[bp->b_npages] = m;
465 bp->b_npages++;
466 }
467 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL)
468 tbp->b_pages[j] = bogus_page;
469 }
470 /*
471 * XXX shouldn't this be += size for both, like in
472 * cluster_wbuild()?
473 *
474 * Don't inherit tbp->b_bufsize as it may be larger due to
475 * a non-page-aligned size. Instead just aggregate using
476 * 'size'.
477 */
478 if (tbp->b_bcount != size)
479 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size);
480 if (tbp->b_bufsize != size)
481 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size);
482 bp->b_bcount += size;
483 bp->b_bufsize += size;
484 }
485
486 /*
487 * Fully valid pages in the cluster are already good and do not need
488 * to be re-read from disk. Replace the page with bogus_page
489 */
490 for (j = 0; j < bp->b_npages; j++) {
491 if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) ==
492 VM_PAGE_BITS_ALL) {
493 bp->b_pages[j] = bogus_page;
494 }
495 }
496 if (bp->b_bufsize > bp->b_kvasize)
497 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
498 bp->b_bufsize, bp->b_kvasize);
499 bp->b_kvasize = bp->b_bufsize;
500
501 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
502 (vm_page_t *)bp->b_pages, bp->b_npages);
503 return (bp);
504}
505
506/*
507 * Cleanup after a clustered read or write.
508 * This is complicated by the fact that any of the buffers might have
509 * extra memory (if there were no empty buffer headers at allocbuf time)
510 * that we will need to shift around.
511 */
512void
513cluster_callback(bp)
514 struct buf *bp;
515{
516 struct buf *nbp, *tbp;
517 int error = 0;
518
519 /*
520 * Must propogate errors to all the components.
521 */
522 if (bp->b_flags & B_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_flags |= B_ERROR;
535 tbp->b_error = error;
536 } else {
537 tbp->b_dirtyoff = tbp->b_dirtyend = 0;
538 tbp->b_flags &= ~(B_ERROR|B_INVAL);
539 /*
540 * XXX the bdwrite()/bqrelse() issued during
541 * cluster building clears B_RELBUF (see bqrelse()
542 * comment). If direct I/O was specified, we have
543 * to restore it here to allow the buffer and VM
544 * to be freed.
545 */
546 if (tbp->b_flags & B_DIRECT)
547 tbp->b_flags |= B_RELBUF;
548 }
549 biodone(tbp);
550 }
551 relpbuf(bp, &cluster_pbuf_freecnt);
552}
553
554/*
555 * cluster_wbuild_wb:
556 *
557 * Implement modified write build for cluster.
558 *
559 * write_behind = 0 write behind disabled
560 * write_behind = 1 write behind normal (default)
561 * write_behind = 2 write behind backed-off
562 */
563
564static __inline int
565cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len)
566{
567 int r = 0;
568
569 switch(write_behind) {
570 case 2:
571 if (start_lbn < len)
572 break;
573 start_lbn -= len;
574 /* fall through */
575 case 1:
576 r = cluster_wbuild(vp, size, start_lbn, len);
577 /* fall through */
578 default:
579 /* fall through */
580 break;
581 }
582 return(r);
583}
584
585/*
586 * Do clustered write for FFS.
587 *
588 * Three cases:
589 * 1. Write is not sequential (write asynchronously)
590 * Write is sequential:
591 * 2. beginning of cluster - begin cluster
592 * 3. middle of a cluster - add to cluster
593 * 4. end of a cluster - asynchronously write cluster
594 */
595void
596cluster_write(bp, filesize, seqcount)
597 struct buf *bp;
598 u_quad_t filesize;
599 int seqcount;
600{
601 struct vnode *vp;
602 daddr_t lbn;
603 int maxclen, cursize;
604 int lblocksize;
605 int async;
606
607 vp = bp->b_vp;
608 if (vp->v_type == VREG) {
609 async = vp->v_mount->mnt_flag & MNT_ASYNC;
610 lblocksize = vp->v_mount->mnt_stat.f_iosize;
611 } else {
612 async = 0;
613 lblocksize = bp->b_bufsize;
614 }
615 lbn = bp->b_lblkno;
616 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset"));
617
618 /* Initialize vnode to beginning of file. */
619 if (lbn == 0)
620 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
621
622 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 ||
623 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) {
624 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1;
625 if (vp->v_clen != 0) {
626 /*
627 * Next block is not sequential.
628 *
629 * If we are not writing at end of file, the process
630 * seeked to another point in the file since its last
631 * write, or we have reached our maximum cluster size,
632 * then push the previous cluster. Otherwise try
633 * reallocating to make it sequential.
634 *
635 * Change to algorithm: only push previous cluster if
636 * it was sequential from the point of view of the
637 * seqcount heuristic, otherwise leave the buffer
638 * intact so we can potentially optimize the I/O
639 * later on in the buf_daemon or update daemon
640 * flush.
641 */
642 cursize = vp->v_lastw - vp->v_cstart + 1;
643 if (((u_quad_t) bp->b_offset + lblocksize) != filesize ||
644 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) {
645 if (!async && seqcount > 0) {
646 cluster_wbuild_wb(vp, lblocksize,
647 vp->v_cstart, cursize);
648 }
649 } else {
650 struct buf **bpp, **endbp;
651 struct cluster_save *buflist;
652
653 buflist = cluster_collectbufs(vp, bp);
654 endbp = &buflist->bs_children
655 [buflist->bs_nchildren - 1];
656 if (VOP_REALLOCBLKS(vp, buflist)) {
657 /*
658 * Failed, push the previous cluster
659 * if *really* writing sequentially
660 * in the logical file (seqcount > 1),
661 * otherwise delay it in the hopes that
662 * the low level disk driver can
663 * optimize the write ordering.
664 */
665 for (bpp = buflist->bs_children;
666 bpp < endbp; bpp++)
667 brelse(*bpp);
668 free(buflist, M_SEGMENT);
669 if (seqcount > 1) {
670 cluster_wbuild_wb(vp,
671 lblocksize, vp->v_cstart,
672 cursize);
673 }
674 } else {
675 /*
676 * Succeeded, keep building cluster.
677 */
678 for (bpp = buflist->bs_children;
679 bpp <= endbp; bpp++)
680 bdwrite(*bpp);
681 free(buflist, M_SEGMENT);
682 vp->v_lastw = lbn;
683 vp->v_lasta = bp->b_blkno;
684 return;
685 }
686 }
687 }
688 /*
689 * Consider beginning a cluster. If at end of file, make
690 * cluster as large as possible, otherwise find size of
691 * existing cluster.
692 */
693 if ((vp->v_type == VREG) &&
694 ((u_quad_t) bp->b_offset + lblocksize) != filesize &&
695 (bp->b_blkno == bp->b_lblkno) &&
696 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) ||
697 bp->b_blkno == -1)) {
698 bawrite(bp);
699 vp->v_clen = 0;
700 vp->v_lasta = bp->b_blkno;
701 vp->v_cstart = lbn + 1;
702 vp->v_lastw = lbn;
703 return;
704 }
705 vp->v_clen = maxclen;
706 if (!async && maxclen == 0) { /* I/O not contiguous */
707 vp->v_cstart = lbn + 1;
708 bawrite(bp);
709 } else { /* Wait for rest of cluster */
710 vp->v_cstart = lbn;
711 bdwrite(bp);
712 }
713 } else if (lbn == vp->v_cstart + vp->v_clen) {
714 /*
715 * At end of cluster, write it out if seqcount tells us we
716 * are operating sequentially, otherwise let the buf or
717 * update daemon handle it.
718 */
719 bdwrite(bp);
720 if (seqcount > 1)
721 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1);
722 vp->v_clen = 0;
723 vp->v_cstart = lbn + 1;
724 } else if (vm_page_count_severe()) {
725 /*
726 * We are low on memory, get it going NOW
727 */
728 bawrite(bp);
729 } else {
730 /*
731 * In the middle of a cluster, so just delay the I/O for now.
732 */
733 bdwrite(bp);
734 }
735 vp->v_lastw = lbn;
736 vp->v_lasta = bp->b_blkno;
737}
738
739
740/*
741 * This is an awful lot like cluster_rbuild...wish they could be combined.
742 * The last lbn argument is the current block on which I/O is being
743 * performed. Check to see that it doesn't fall in the middle of
744 * the current block (if last_bp == NULL).
745 */
746int
747cluster_wbuild(vp, size, start_lbn, len)
748 struct vnode *vp;
749 long size;
750 daddr_t start_lbn;
751 int len;
752{
753 struct buf *bp, *tbp;
754 int i, j, s;
755 int totalwritten = 0;
756 int dbsize = btodb(size);
757
758 while (len > 0) {
759 s = splbio();
760 /*
761 * If the buffer is not delayed-write (i.e. dirty), or it
762 * is delayed-write but either locked or inval, it cannot
763 * partake in the clustered write.
764 */
765 if (((tbp = gbincore(vp, start_lbn)) == NULL) ||
766 ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) ||
767 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) {
768 ++start_lbn;
769 --len;
770 splx(s);
771 continue;
772 }
773 bremfree(tbp);
774 tbp->b_flags &= ~B_DONE;
775 splx(s);
776
777 /*
778 * Extra memory in the buffer, punt on this buffer.
779 * XXX we could handle this in most cases, but we would
780 * have to push the extra memory down to after our max
781 * possible cluster size and then potentially pull it back
782 * up if the cluster was terminated prematurely--too much
783 * hassle.
784 */
785 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) ||
786 (tbp->b_bcount != tbp->b_bufsize) ||
787 (tbp->b_bcount != size) ||
788 (len == 1) ||
789 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) {
790 totalwritten += tbp->b_bufsize;
791 bawrite(tbp);
792 ++start_lbn;
793 --len;
794 continue;
795 }
796
797 /*
798 * We got a pbuf to make the cluster in.
799 * so initialise it.
800 */
801 TAILQ_INIT(&bp->b_cluster.cluster_head);
802 bp->b_bcount = 0;
803 bp->b_bufsize = 0;
804 bp->b_npages = 0;
805 if (tbp->b_wcred != NOCRED) {
806 bp->b_wcred = tbp->b_wcred;
807 crhold(bp->b_wcred);
808 }
809
810 bp->b_blkno = tbp->b_blkno;
811 bp->b_lblkno = tbp->b_lblkno;
812 bp->b_offset = tbp->b_offset;
813
814 /*
815 * We are synthesizing a buffer out of vm_page_t's, but
816 * if the block size is not page aligned then the starting
817 * address may not be either. Inherit the b_data offset
818 * from the original buffer.
819 */
820 bp->b_data = (char *)((vm_offset_t)bp->b_data |
821 ((vm_offset_t)tbp->b_data & PAGE_MASK));
822 bp->b_flags |= B_CALL | B_CLUSTER |
823 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT | B_NOWDRAIN));
824 bp->b_iodone = cluster_callback;
825 pbgetvp(vp, bp);
826 /*
827 * From this location in the file, scan forward to see
828 * if there are buffers with adjacent data that need to
829 * be written as well.
830 */
831 for (i = 0; i < len; ++i, ++start_lbn) {
832 if (i != 0) { /* If not the first buffer */
833 s = splbio();
834 /*
835 * If the adjacent data is not even in core it
836 * can't need to be written.
837 */
838 if ((tbp = gbincore(vp, start_lbn)) == NULL) {
839 splx(s);
840 break;
841 }
842
843 /*
844 * If it IS in core, but has different
845 * characteristics, or is locked (which
846 * means it could be undergoing a background
847 * I/O or be in a weird state), then don't
848 * cluster with it.
849 */
850 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK |
851 B_INVAL | B_DELWRI | B_NEEDCOMMIT))
852 != (B_DELWRI | B_CLUSTEROK |
853 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) ||
854 (tbp->b_flags & B_LOCKED) ||
855 tbp->b_wcred != bp->b_wcred ||
856 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) {
857 splx(s);
858 break;
859 }
860
861 /*
862 * Check that the combined cluster
863 * would make sense with regard to pages
864 * and would not be too large
865 */
866 if ((tbp->b_bcount != size) ||
867 ((bp->b_blkno + (dbsize * i)) !=
868 tbp->b_blkno) ||
869 ((tbp->b_npages + bp->b_npages) >
870 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) {
871 BUF_UNLOCK(tbp);
872 splx(s);
873 break;
874 }
875 /*
876 * Ok, it's passed all the tests,
877 * so remove it from the free list
878 * and mark it busy. We will use it.
879 */
880 bremfree(tbp);
881 tbp->b_flags &= ~B_DONE;
882 splx(s);
883 } /* end of code for non-first buffers only */
884 /* check for latent dependencies to be handled */
885 if ((LIST_FIRST(&tbp->b_dep)) != NULL &&
886 bioops.io_start)
887 (*bioops.io_start)(tbp);
888 /*
889 * If the IO is via the VM then we do some
890 * special VM hackery (yuck). Since the buffer's
891 * block size may not be page-aligned it is possible
892 * for a page to be shared between two buffers. We
893 * have to get rid of the duplication when building
894 * the cluster.
895 */
896 if (tbp->b_flags & B_VMIO) {
897 vm_page_t m;
898
899 if (i != 0) { /* if not first buffer */
900 for (j = 0; j < tbp->b_npages; j += 1) {
901 m = tbp->b_pages[j];
902 if (m->flags & PG_BUSY) {
903 bqrelse(tbp);
904 goto finishcluster;
905 }
906 }
907 }
908
909 for (j = 0; j < tbp->b_npages; j += 1) {
910 m = tbp->b_pages[j];
911 vm_page_io_start(m);
912 vm_object_pip_add(m->object, 1);
913 if ((bp->b_npages == 0) ||
914 (bp->b_pages[bp->b_npages - 1] != m)) {
915 bp->b_pages[bp->b_npages] = m;
916 bp->b_npages++;
917 }
918 }
919 }
920 bp->b_bcount += size;
921 bp->b_bufsize += size;
922
923 s = splbio();
924 bundirty(tbp);
925 tbp->b_flags &= ~(B_READ | B_DONE | B_ERROR);
926 tbp->b_flags |= B_ASYNC;
927 reassignbuf(tbp, tbp->b_vp); /* put on clean list */
928 ++tbp->b_vp->v_numoutput;
929 splx(s);
930 BUF_KERNPROC(tbp);
931 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
932 tbp, b_cluster.cluster_entry);
933 }
934 finishcluster:
935 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
936 (vm_page_t *) bp->b_pages, bp->b_npages);
937 if (bp->b_bufsize > bp->b_kvasize)
938 panic(
939 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
940 bp->b_bufsize, bp->b_kvasize);
941 bp->b_kvasize = bp->b_bufsize;
942 totalwritten += bp->b_bufsize;
943 bp->b_dirtyoff = 0;
944 bp->b_dirtyend = bp->b_bufsize;
945 bawrite(bp);
946
947 len -= i;
948 }
949 return totalwritten;
950}
951
952/*
953 * Collect together all the buffers in a cluster.
954 * Plus add one additional buffer.
955 */
956static struct cluster_save *
957cluster_collectbufs(vp, last_bp)
958 struct vnode *vp;
959 struct buf *last_bp;
960{
961 struct cluster_save *buflist;
962 struct buf *bp;
963 daddr_t lbn;
964 int i, len;
965
966 len = vp->v_lastw - vp->v_cstart + 1;
967 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
968 M_SEGMENT, M_WAITOK);
969 buflist->bs_nchildren = 0;
970 buflist->bs_children = (struct buf **) (buflist + 1);
971 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) {
972 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp);
973 buflist->bs_children[i] = bp;
974 if (bp->b_blkno == bp->b_lblkno)
975 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno,
976 NULL, NULL);
977 }
978 buflist->bs_children[i] = bp = last_bp;
979 if (bp->b_blkno == bp->b_lblkno)
980 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno,
981 NULL, NULL);
982 buflist->bs_nchildren = i + 1;
983 return (buflist);
984}