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 * 4. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94
32 */
33
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD: releng/9.1/sys/kern/vfs_cluster.c 231936 2012-02-20 11:27:37Z kib $");
36
37 #include "opt_debug_cluster.h"
38
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/kernel.h>
42 #include <sys/proc.h>
43 #include <sys/bio.h>
44 #include <sys/buf.h>
45 #include <sys/vnode.h>
46 #include <sys/malloc.h>
47 #include <sys/mount.h>
48 #include <sys/resourcevar.h>
49 #include <sys/vmmeter.h>
50 #include <vm/vm.h>
51 #include <vm/vm_object.h>
52 #include <vm/vm_page.h>
53 #include <sys/sysctl.h>
54
55 #if defined(CLUSTERDEBUG)
56 static int rcluster= 0;
57 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0,
58 "Debug VFS clustering code");
59 #endif
60
61 static MALLOC_DEFINE(M_SEGMENT, "cl_savebuf", "cluster_save buffer");
62
63 static struct cluster_save *
64 cluster_collectbufs(struct vnode *vp, struct buf *last_bp);
65 static struct buf *
66 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn,
67 daddr_t blkno, long size, int run, struct buf *fbp);
68 static void cluster_callback(struct buf *);
69
70 static int write_behind = 1;
71 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0,
72 "Cluster write-behind; 0: disable, 1: enable, 2: backed off");
73
74 static int read_max = 64;
75 SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0,
76 "Cluster read-ahead max block count");
77
78 /* Page expended to mark partially backed buffers */
79 extern vm_page_t bogus_page;
80
81 /*
82 * Read data to a buf, including read-ahead if we find this to be beneficial.
83 * cluster_read replaces bread.
84 */
85 int
86 cluster_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 struct bufobj *bo;
98 daddr_t blkno, origblkno;
99 int maxra, racluster;
100 int error, ncontig;
101 int i;
102
103 error = 0;
104 bo = &vp->v_bufobj;
105
106 /*
107 * Try to limit the amount of read-ahead by a few
108 * ad-hoc parameters. This needs work!!!
109 */
110 racluster = vp->v_mount->mnt_iosize_max / size;
111 maxra = seqcount;
112 maxra = min(read_max, maxra);
113 maxra = min(nbuf/8, maxra);
114 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize)
115 maxra = (filesize / size) - lblkno;
116
117 /*
118 * get the requested block
119 */
120 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, 0);
121 origblkno = lblkno;
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 bp->b_flags &= ~B_RAM;
135 BO_LOCK(bo);
136 for (i = 1; i < maxra; i++) {
137 /*
138 * Stop if the buffer does not exist or it
139 * is invalid (about to go away?)
140 */
141 rbp = gbincore(&vp->v_bufobj, lblkno+i);
142 if (rbp == NULL || (rbp->b_flags & B_INVAL))
143 break;
144
145 /*
146 * Set another read-ahead mark so we know
147 * to check again. (If we can lock the
148 * buffer without waiting)
149 */
150 if ((((i % racluster) == (racluster - 1)) ||
151 (i == (maxra - 1)))
152 && (0 == BUF_LOCK(rbp,
153 LK_EXCLUSIVE | LK_NOWAIT, NULL))) {
154 rbp->b_flags |= B_RAM;
155 BUF_UNLOCK(rbp);
156 }
157 }
158 BO_UNLOCK(bo);
159 if (i >= maxra) {
160 return 0;
161 }
162 lblkno += i;
163 }
164 reqbp = bp = NULL;
165 /*
166 * If it isn't in the cache, then get a chunk from
167 * disk if sequential, otherwise just get the block.
168 */
169 } else {
170 off_t firstread = bp->b_offset;
171 int nblks;
172
173 KASSERT(bp->b_offset != NOOFFSET,
174 ("cluster_read: no buffer offset"));
175
176 ncontig = 0;
177
178 /*
179 * Compute the total number of blocks that we should read
180 * synchronously.
181 */
182 if (firstread + totread > filesize)
183 totread = filesize - firstread;
184 nblks = howmany(totread, size);
185 if (nblks > racluster)
186 nblks = racluster;
187
188 /*
189 * Now compute the number of contiguous blocks.
190 */
191 if (nblks > 1) {
192 error = VOP_BMAP(vp, lblkno, NULL,
193 &blkno, &ncontig, NULL);
194 /*
195 * If this failed to map just do the original block.
196 */
197 if (error || blkno == -1)
198 ncontig = 0;
199 }
200
201 /*
202 * If we have contiguous data available do a cluster
203 * otherwise just read the requested block.
204 */
205 if (ncontig) {
206 /* Account for our first block. */
207 ncontig = min(ncontig + 1, nblks);
208 if (ncontig < nblks)
209 nblks = ncontig;
210 bp = cluster_rbuild(vp, filesize, lblkno,
211 blkno, size, nblks, bp);
212 lblkno += (bp->b_bufsize / size);
213 } else {
214 bp->b_flags |= B_RAM;
215 bp->b_iocmd = BIO_READ;
216 lblkno += 1;
217 }
218 }
219
220 /*
221 * handle the synchronous read so that it is available ASAP.
222 */
223 if (bp) {
224 if ((bp->b_flags & B_CLUSTER) == 0) {
225 vfs_busy_pages(bp, 0);
226 }
227 bp->b_flags &= ~B_INVAL;
228 bp->b_ioflags &= ~BIO_ERROR;
229 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL)
230 BUF_KERNPROC(bp);
231 bp->b_iooffset = dbtob(bp->b_blkno);
232 bstrategy(bp);
233 curthread->td_ru.ru_inblock++;
234 }
235
236 /*
237 * If we have been doing sequential I/O, then do some read-ahead.
238 */
239 while (lblkno < (origblkno + maxra)) {
240 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL);
241 if (error)
242 break;
243
244 if (blkno == -1)
245 break;
246
247 /*
248 * We could throttle ncontig here by maxra but we might as
249 * well read the data if it is contiguous. We're throttled
250 * by racluster anyway.
251 */
252 if (ncontig) {
253 ncontig = min(ncontig + 1, racluster);
254 rbp = cluster_rbuild(vp, filesize, lblkno, blkno,
255 size, ncontig, NULL);
256 lblkno += (rbp->b_bufsize / size);
257 if (rbp->b_flags & B_DELWRI) {
258 bqrelse(rbp);
259 continue;
260 }
261 } else {
262 rbp = getblk(vp, lblkno, size, 0, 0, 0);
263 lblkno += 1;
264 if (rbp->b_flags & B_DELWRI) {
265 bqrelse(rbp);
266 continue;
267 }
268 rbp->b_flags |= B_ASYNC | B_RAM;
269 rbp->b_iocmd = BIO_READ;
270 rbp->b_blkno = blkno;
271 }
272 if (rbp->b_flags & B_CACHE) {
273 rbp->b_flags &= ~B_ASYNC;
274 bqrelse(rbp);
275 continue;
276 }
277 if ((rbp->b_flags & B_CLUSTER) == 0) {
278 vfs_busy_pages(rbp, 0);
279 }
280 rbp->b_flags &= ~B_INVAL;
281 rbp->b_ioflags &= ~BIO_ERROR;
282 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL)
283 BUF_KERNPROC(rbp);
284 rbp->b_iooffset = dbtob(rbp->b_blkno);
285 bstrategy(rbp);
286 curthread->td_ru.ru_inblock++;
287 }
288
289 if (reqbp)
290 return (bufwait(reqbp));
291 else
292 return (error);
293 }
294
295 /*
296 * If blocks are contiguous on disk, use this to provide clustered
297 * read ahead. We will read as many blocks as possible sequentially
298 * and then parcel them up into logical blocks in the buffer hash table.
299 */
300 static struct buf *
301 cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp)
302 struct vnode *vp;
303 u_quad_t filesize;
304 daddr_t lbn;
305 daddr_t blkno;
306 long size;
307 int run;
308 struct buf *fbp;
309 {
310 struct bufobj *bo;
311 struct buf *bp, *tbp;
312 daddr_t bn;
313 off_t off;
314 long tinc, tsize;
315 int i, inc, j, toff;
316
317 KASSERT(size == vp->v_mount->mnt_stat.f_iosize,
318 ("cluster_rbuild: size %ld != filesize %jd\n",
319 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize));
320
321 /*
322 * avoid a division
323 */
324 while ((u_quad_t) size * (lbn + run) > filesize) {
325 --run;
326 }
327
328 if (fbp) {
329 tbp = fbp;
330 tbp->b_iocmd = BIO_READ;
331 } else {
332 tbp = getblk(vp, lbn, size, 0, 0, 0);
333 if (tbp->b_flags & B_CACHE)
334 return tbp;
335 tbp->b_flags |= B_ASYNC | B_RAM;
336 tbp->b_iocmd = BIO_READ;
337 }
338 tbp->b_blkno = blkno;
339 if( (tbp->b_flags & B_MALLOC) ||
340 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) )
341 return tbp;
342
343 bp = trypbuf(&cluster_pbuf_freecnt);
344 if (bp == 0)
345 return tbp;
346
347 /*
348 * We are synthesizing a buffer out of vm_page_t's, but
349 * if the block size is not page aligned then the starting
350 * address may not be either. Inherit the b_data offset
351 * from the original buffer.
352 */
353 bp->b_data = (char *)((vm_offset_t)bp->b_data |
354 ((vm_offset_t)tbp->b_data & PAGE_MASK));
355 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO;
356 bp->b_iocmd = BIO_READ;
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 bo = &vp->v_bufobj;
372 for (bn = blkno, i = 0; i < run; ++i, bn += inc) {
373 if (i != 0) {
374 if ((bp->b_npages * PAGE_SIZE) +
375 round_page(size) > vp->v_mount->mnt_iosize_max) {
376 break;
377 }
378
379 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT);
380
381 /* Don't wait around for locked bufs. */
382 if (tbp == NULL)
383 break;
384
385 /*
386 * Stop scanning if the buffer is fully valid
387 * (marked B_CACHE), or locked (may be doing a
388 * background write), or if the buffer is not
389 * VMIO backed. The clustering code can only deal
390 * with VMIO-backed buffers.
391 */
392 BO_LOCK(bo);
393 if ((tbp->b_vflags & BV_BKGRDINPROG) ||
394 (tbp->b_flags & B_CACHE) ||
395 (tbp->b_flags & B_VMIO) == 0) {
396 BO_UNLOCK(bo);
397 bqrelse(tbp);
398 break;
399 }
400 BO_UNLOCK(bo);
401
402 /*
403 * The buffer must be completely invalid in order to
404 * take part in the cluster. If it is partially valid
405 * then we stop.
406 */
407 off = tbp->b_offset;
408 tsize = size;
409 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object);
410 for (j = 0; tsize > 0; j++) {
411 toff = off & PAGE_MASK;
412 tinc = tsize;
413 if (toff + tinc > PAGE_SIZE)
414 tinc = PAGE_SIZE - toff;
415 VM_OBJECT_LOCK_ASSERT(tbp->b_pages[j]->object,
416 MA_OWNED);
417 if ((tbp->b_pages[j]->valid &
418 vm_page_bits(toff, tinc)) != 0)
419 break;
420 off += tinc;
421 tsize -= tinc;
422 }
423 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object);
424 if (tsize > 0) {
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_ASYNC;
443 tbp->b_iocmd = BIO_READ;
444 if (tbp->b_blkno == tbp->b_lblkno) {
445 tbp->b_blkno = bn;
446 } else if (tbp->b_blkno != bn) {
447 brelse(tbp);
448 break;
449 }
450 }
451 /*
452 * XXX fbp from caller may not be B_ASYNC, but we are going
453 * to biodone() it in cluster_callback() anyway
454 */
455 BUF_KERNPROC(tbp);
456 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
457 tbp, b_cluster.cluster_entry);
458 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object);
459 for (j = 0; j < tbp->b_npages; j += 1) {
460 vm_page_t m;
461 m = tbp->b_pages[j];
462 vm_page_io_start(m);
463 vm_object_pip_add(m->object, 1);
464 if ((bp->b_npages == 0) ||
465 (bp->b_pages[bp->b_npages-1] != m)) {
466 bp->b_pages[bp->b_npages] = m;
467 bp->b_npages++;
468 }
469 if (m->valid == VM_PAGE_BITS_ALL)
470 tbp->b_pages[j] = bogus_page;
471 }
472 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object);
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 VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
491 for (j = 0; j < bp->b_npages; j++) {
492 VM_OBJECT_LOCK_ASSERT(bp->b_pages[j]->object, MA_OWNED);
493 if (bp->b_pages[j]->valid == VM_PAGE_BITS_ALL)
494 bp->b_pages[j] = bogus_page;
495 }
496 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object);
497 if (bp->b_bufsize > bp->b_kvasize)
498 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
499 bp->b_bufsize, bp->b_kvasize);
500 bp->b_kvasize = bp->b_bufsize;
501
502 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
503 (vm_page_t *)bp->b_pages, bp->b_npages);
504 return (bp);
505 }
506
507 /*
508 * Cleanup after a clustered read or write.
509 * This is complicated by the fact that any of the buffers might have
510 * extra memory (if there were no empty buffer headers at allocbuf time)
511 * that we will need to shift around.
512 */
513 static void
514 cluster_callback(bp)
515 struct buf *bp;
516 {
517 struct buf *nbp, *tbp;
518 int error = 0;
519
520 /*
521 * Must propogate errors to all the components.
522 */
523 if (bp->b_ioflags & BIO_ERROR)
524 error = bp->b_error;
525
526 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages);
527 /*
528 * Move memory from the large cluster buffer into the component
529 * buffers and mark IO as done on these.
530 */
531 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head);
532 tbp; tbp = nbp) {
533 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry);
534 if (error) {
535 tbp->b_ioflags |= BIO_ERROR;
536 tbp->b_error = error;
537 } else {
538 tbp->b_dirtyoff = tbp->b_dirtyend = 0;
539 tbp->b_flags &= ~B_INVAL;
540 tbp->b_ioflags &= ~BIO_ERROR;
541 /*
542 * XXX the bdwrite()/bqrelse() issued during
543 * cluster building clears B_RELBUF (see bqrelse()
544 * comment). If direct I/O was specified, we have
545 * to restore it here to allow the buffer and VM
546 * to be freed.
547 */
548 if (tbp->b_flags & B_DIRECT)
549 tbp->b_flags |= B_RELBUF;
550 }
551 bufdone(tbp);
552 }
553 pbrelvp(bp);
554 relpbuf(bp, &cluster_pbuf_freecnt);
555 }
556
557 /*
558 * cluster_wbuild_wb:
559 *
560 * Implement modified write build for cluster.
561 *
562 * write_behind = 0 write behind disabled
563 * write_behind = 1 write behind normal (default)
564 * write_behind = 2 write behind backed-off
565 */
566
567 static __inline int
568 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len)
569 {
570 int r = 0;
571
572 switch(write_behind) {
573 case 2:
574 if (start_lbn < len)
575 break;
576 start_lbn -= len;
577 /* FALLTHROUGH */
578 case 1:
579 r = cluster_wbuild(vp, size, start_lbn, len);
580 /* FALLTHROUGH */
581 default:
582 /* FALLTHROUGH */
583 break;
584 }
585 return(r);
586 }
587
588 /*
589 * Do clustered write for FFS.
590 *
591 * Three cases:
592 * 1. Write is not sequential (write asynchronously)
593 * Write is sequential:
594 * 2. beginning of cluster - begin cluster
595 * 3. middle of a cluster - add to cluster
596 * 4. end of a cluster - asynchronously write cluster
597 */
598 void
599 cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount)
600 {
601 daddr_t lbn;
602 int maxclen, cursize;
603 int lblocksize;
604 int async;
605
606 if (vp->v_type == VREG) {
607 async = DOINGASYNC(vp);
608 lblocksize = vp->v_mount->mnt_stat.f_iosize;
609 } else {
610 async = 0;
611 lblocksize = bp->b_bufsize;
612 }
613 lbn = bp->b_lblkno;
614 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset"));
615
616 /* Initialize vnode to beginning of file. */
617 if (lbn == 0)
618 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
619
620 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 ||
621 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) {
622 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1;
623 if (vp->v_clen != 0) {
624 /*
625 * Next block is not sequential.
626 *
627 * If we are not writing at end of file, the process
628 * seeked to another point in the file since its last
629 * write, or we have reached our maximum cluster size,
630 * then push the previous cluster. Otherwise try
631 * reallocating to make it sequential.
632 *
633 * Change to algorithm: only push previous cluster if
634 * it was sequential from the point of view of the
635 * seqcount heuristic, otherwise leave the buffer
636 * intact so we can potentially optimize the I/O
637 * later on in the buf_daemon or update daemon
638 * flush.
639 */
640 cursize = vp->v_lastw - vp->v_cstart + 1;
641 if (((u_quad_t) bp->b_offset + lblocksize) != filesize ||
642 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) {
643 if (!async && seqcount > 0) {
644 cluster_wbuild_wb(vp, lblocksize,
645 vp->v_cstart, cursize);
646 }
647 } else {
648 struct buf **bpp, **endbp;
649 struct cluster_save *buflist;
650
651 buflist = cluster_collectbufs(vp, bp);
652 endbp = &buflist->bs_children
653 [buflist->bs_nchildren - 1];
654 if (VOP_REALLOCBLKS(vp, buflist)) {
655 /*
656 * Failed, push the previous cluster
657 * if *really* writing sequentially
658 * in the logical file (seqcount > 1),
659 * otherwise delay it in the hopes that
660 * the low level disk driver can
661 * optimize the write ordering.
662 */
663 for (bpp = buflist->bs_children;
664 bpp < endbp; bpp++)
665 brelse(*bpp);
666 free(buflist, M_SEGMENT);
667 if (seqcount > 1) {
668 cluster_wbuild_wb(vp,
669 lblocksize, vp->v_cstart,
670 cursize);
671 }
672 } else {
673 /*
674 * Succeeded, keep building cluster.
675 */
676 for (bpp = buflist->bs_children;
677 bpp <= endbp; bpp++)
678 bdwrite(*bpp);
679 free(buflist, M_SEGMENT);
680 vp->v_lastw = lbn;
681 vp->v_lasta = bp->b_blkno;
682 return;
683 }
684 }
685 }
686 /*
687 * Consider beginning a cluster. If at end of file, make
688 * cluster as large as possible, otherwise find size of
689 * existing cluster.
690 */
691 if ((vp->v_type == VREG) &&
692 ((u_quad_t) bp->b_offset + lblocksize) != filesize &&
693 (bp->b_blkno == bp->b_lblkno) &&
694 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) ||
695 bp->b_blkno == -1)) {
696 bawrite(bp);
697 vp->v_clen = 0;
698 vp->v_lasta = bp->b_blkno;
699 vp->v_cstart = lbn + 1;
700 vp->v_lastw = lbn;
701 return;
702 }
703 vp->v_clen = maxclen;
704 if (!async && maxclen == 0) { /* I/O not contiguous */
705 vp->v_cstart = lbn + 1;
706 bawrite(bp);
707 } else { /* Wait for rest of cluster */
708 vp->v_cstart = lbn;
709 bdwrite(bp);
710 }
711 } else if (lbn == vp->v_cstart + vp->v_clen) {
712 /*
713 * At end of cluster, write it out if seqcount tells us we
714 * are operating sequentially, otherwise let the buf or
715 * update daemon handle it.
716 */
717 bdwrite(bp);
718 if (seqcount > 1)
719 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1);
720 vp->v_clen = 0;
721 vp->v_cstart = lbn + 1;
722 } else if (vm_page_count_severe()) {
723 /*
724 * We are low on memory, get it going NOW
725 */
726 bawrite(bp);
727 } else {
728 /*
729 * In the middle of a cluster, so just delay the I/O for now.
730 */
731 bdwrite(bp);
732 }
733 vp->v_lastw = lbn;
734 vp->v_lasta = bp->b_blkno;
735 }
736
737
738 /*
739 * This is an awful lot like cluster_rbuild...wish they could be combined.
740 * The last lbn argument is the current block on which I/O is being
741 * performed. Check to see that it doesn't fall in the middle of
742 * the current block (if last_bp == NULL).
743 */
744 int
745 cluster_wbuild(vp, size, start_lbn, len)
746 struct vnode *vp;
747 long size;
748 daddr_t start_lbn;
749 int len;
750 {
751 struct buf *bp, *tbp;
752 struct bufobj *bo;
753 int i, j;
754 int totalwritten = 0;
755 int dbsize = btodb(size);
756
757 bo = &vp->v_bufobj;
758 while (len > 0) {
759 /*
760 * If the buffer is not delayed-write (i.e. dirty), or it
761 * is delayed-write but either locked or inval, it cannot
762 * partake in the clustered write.
763 */
764 BO_LOCK(bo);
765 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL ||
766 (tbp->b_vflags & BV_BKGRDINPROG)) {
767 BO_UNLOCK(bo);
768 ++start_lbn;
769 --len;
770 continue;
771 }
772 if (BUF_LOCK(tbp,
773 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, BO_MTX(bo))) {
774 ++start_lbn;
775 --len;
776 continue;
777 }
778 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) {
779 BUF_UNLOCK(tbp);
780 ++start_lbn;
781 --len;
782 continue;
783 }
784 if (tbp->b_pin_count > 0) {
785 BUF_UNLOCK(tbp);
786 ++start_lbn;
787 --len;
788 continue;
789 }
790 bremfree(tbp);
791 tbp->b_flags &= ~B_DONE;
792
793 /*
794 * Extra memory in the buffer, punt on this buffer.
795 * XXX we could handle this in most cases, but we would
796 * have to push the extra memory down to after our max
797 * possible cluster size and then potentially pull it back
798 * up if the cluster was terminated prematurely--too much
799 * hassle.
800 */
801 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) !=
802 (B_CLUSTEROK | B_VMIO)) ||
803 (tbp->b_bcount != tbp->b_bufsize) ||
804 (tbp->b_bcount != size) ||
805 (len == 1) ||
806 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) {
807 totalwritten += tbp->b_bufsize;
808 bawrite(tbp);
809 ++start_lbn;
810 --len;
811 continue;
812 }
813
814 /*
815 * We got a pbuf to make the cluster in.
816 * so initialise it.
817 */
818 TAILQ_INIT(&bp->b_cluster.cluster_head);
819 bp->b_bcount = 0;
820 bp->b_bufsize = 0;
821 bp->b_npages = 0;
822 if (tbp->b_wcred != NOCRED)
823 bp->b_wcred = crhold(tbp->b_wcred);
824
825 bp->b_blkno = tbp->b_blkno;
826 bp->b_lblkno = tbp->b_lblkno;
827 bp->b_offset = tbp->b_offset;
828
829 /*
830 * We are synthesizing a buffer out of vm_page_t's, but
831 * if the block size is not page aligned then the starting
832 * address may not be either. Inherit the b_data offset
833 * from the original buffer.
834 */
835 bp->b_data = (char *)((vm_offset_t)bp->b_data |
836 ((vm_offset_t)tbp->b_data & PAGE_MASK));
837 bp->b_flags |= B_CLUSTER |
838 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT));
839 bp->b_iodone = cluster_callback;
840 pbgetvp(vp, bp);
841 /*
842 * From this location in the file, scan forward to see
843 * if there are buffers with adjacent data that need to
844 * be written as well.
845 */
846 for (i = 0; i < len; ++i, ++start_lbn) {
847 if (i != 0) { /* If not the first buffer */
848 /*
849 * If the adjacent data is not even in core it
850 * can't need to be written.
851 */
852 BO_LOCK(bo);
853 if ((tbp = gbincore(bo, start_lbn)) == NULL ||
854 (tbp->b_vflags & BV_BKGRDINPROG)) {
855 BO_UNLOCK(bo);
856 break;
857 }
858
859 /*
860 * If it IS in core, but has different
861 * characteristics, or is locked (which
862 * means it could be undergoing a background
863 * I/O or be in a weird state), then don't
864 * cluster with it.
865 */
866 if (BUF_LOCK(tbp,
867 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK,
868 BO_MTX(bo)))
869 break;
870
871 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK |
872 B_INVAL | B_DELWRI | B_NEEDCOMMIT))
873 != (B_DELWRI | B_CLUSTEROK |
874 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) ||
875 tbp->b_wcred != bp->b_wcred) {
876 BUF_UNLOCK(tbp);
877 break;
878 }
879
880 /*
881 * Check that the combined cluster
882 * would make sense with regard to pages
883 * and would not be too large
884 */
885 if ((tbp->b_bcount != size) ||
886 ((bp->b_blkno + (dbsize * i)) !=
887 tbp->b_blkno) ||
888 ((tbp->b_npages + bp->b_npages) >
889 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) {
890 BUF_UNLOCK(tbp);
891 break;
892 }
893
894 /*
895 * Do not pull in pinned buffers.
896 */
897 if (tbp->b_pin_count > 0) {
898 BUF_UNLOCK(tbp);
899 break;
900 }
901
902 /*
903 * Ok, it's passed all the tests,
904 * so remove it from the free list
905 * and mark it busy. We will use it.
906 */
907 bremfree(tbp);
908 tbp->b_flags &= ~B_DONE;
909 } /* end of code for non-first buffers only */
910 /*
911 * If the IO is via the VM then we do some
912 * special VM hackery (yuck). Since the buffer's
913 * block size may not be page-aligned it is possible
914 * for a page to be shared between two buffers. We
915 * have to get rid of the duplication when building
916 * the cluster.
917 */
918 if (tbp->b_flags & B_VMIO) {
919 vm_page_t m;
920
921 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object);
922 if (i != 0) { /* if not first buffer */
923 for (j = 0; j < tbp->b_npages; j += 1) {
924 m = tbp->b_pages[j];
925 if (m->oflags & VPO_BUSY) {
926 VM_OBJECT_UNLOCK(
927 tbp->b_object);
928 bqrelse(tbp);
929 goto finishcluster;
930 }
931 }
932 }
933 for (j = 0; j < tbp->b_npages; j += 1) {
934 m = tbp->b_pages[j];
935 vm_page_io_start(m);
936 vm_object_pip_add(m->object, 1);
937 if ((bp->b_npages == 0) ||
938 (bp->b_pages[bp->b_npages - 1] != m)) {
939 bp->b_pages[bp->b_npages] = m;
940 bp->b_npages++;
941 }
942 }
943 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object);
944 }
945 bp->b_bcount += size;
946 bp->b_bufsize += size;
947 bundirty(tbp);
948 tbp->b_flags &= ~B_DONE;
949 tbp->b_ioflags &= ~BIO_ERROR;
950 tbp->b_flags |= B_ASYNC;
951 tbp->b_iocmd = BIO_WRITE;
952 reassignbuf(tbp); /* put on clean list */
953 bufobj_wref(tbp->b_bufobj);
954 BUF_KERNPROC(tbp);
955 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
956 tbp, b_cluster.cluster_entry);
957 }
958 finishcluster:
959 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
960 (vm_page_t *) bp->b_pages, bp->b_npages);
961 if (bp->b_bufsize > bp->b_kvasize)
962 panic(
963 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
964 bp->b_bufsize, bp->b_kvasize);
965 bp->b_kvasize = bp->b_bufsize;
966 totalwritten += bp->b_bufsize;
967 bp->b_dirtyoff = 0;
968 bp->b_dirtyend = bp->b_bufsize;
969 bawrite(bp);
970
971 len -= i;
972 }
973 return totalwritten;
974 }
975
976 /*
977 * Collect together all the buffers in a cluster.
978 * Plus add one additional buffer.
979 */
980 static struct cluster_save *
981 cluster_collectbufs(vp, last_bp)
982 struct vnode *vp;
983 struct buf *last_bp;
984 {
985 struct cluster_save *buflist;
986 struct buf *bp;
987 daddr_t lbn;
988 int i, len;
989
990 len = vp->v_lastw - vp->v_cstart + 1;
991 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
992 M_SEGMENT, M_WAITOK);
993 buflist->bs_nchildren = 0;
994 buflist->bs_children = (struct buf **) (buflist + 1);
995 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) {
996 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp);
997 buflist->bs_children[i] = bp;
998 if (bp->b_blkno == bp->b_lblkno)
999 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno,
1000 NULL, NULL);
1001 }
1002 buflist->bs_children[i] = bp = last_bp;
1003 if (bp->b_blkno == bp->b_lblkno)
1004 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL);
1005 buflist->bs_nchildren = i + 1;
1006 return (buflist);
1007 }
Cache object: 6ab72ff1d023ab0c1117849fac9cb898
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