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libstand.3: add HAMMER and MS-DOS filesystems and improve mark-up
[dragonfly.git] / sys / kern / vfs_cluster.c
blobb1f43c4c56aab1eae4a5064d972ef1536a5e2a73
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 * $DragonFly: src/sys/kern/vfs_cluster.c,v 1.40 2008/07/14 03:09:00 dillon Exp $
38 */
39
40 #include "opt_debug_cluster.h"
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/proc.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 #include <sys/buf2.h>
57 #include <vm/vm_page2.h>
58
59 #if defined(CLUSTERDEBUG)
60 #include <sys/sysctl.h>
61 static int rcluster= 0;
62 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, "");
63 #endif
64
65 static MALLOC_DEFINE(M_SEGMENT, "cluster_save", "cluster_save buffer");
66
67 static struct cluster_save *
68 cluster_collectbufs (struct vnode *vp, struct buf *last_bp,
69 int blksize);
70 static struct buf *
71 cluster_rbuild (struct vnode *vp, off_t filesize, off_t loffset,
72 off_t doffset, int blksize, int run,
73 struct buf *fbp, int doasync);
74 static void cluster_callback (struct bio *);
75
76
77 static int write_behind = 1;
78 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, "");
79
80 extern vm_page_t bogus_page;
81
82 extern int cluster_pbuf_freecnt;
83
84 /*
85 * Maximum number of blocks for read-ahead.
86 */
87 #define MAXRA 32
88
89 /*
90 * This replaces bread.
91 */
92 int
93 cluster_read(struct vnode *vp, off_t filesize, off_t loffset,
94 int blksize, int totread, int seqcount, struct buf **bpp)
95 {
96 struct buf *bp, *rbp, *reqbp;
97 off_t origoffset;
98 off_t doffset;
99 int error;
100 int i;
101 int maxra, racluster;
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 = vmaxiosize(vp) / blksize;
110 maxra = 2 * racluster + (totread / blksize);
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, loffset, blksize, 0, 0);
120 origoffset = loffset;
121
122 /*
123 * if it is in the cache, then check to see if the reads have been
124 * sequential. If they have, then try some read-ahead, otherwise
125 * back-off on prospective read-aheads.
126 */
127 if (bp->b_flags & B_CACHE) {
128 if (!seqcount) {
129 return 0;
130 } else if ((bp->b_flags & B_RAM) == 0) {
131 return 0;
132 } else {
133 struct buf *tbp;
134 bp->b_flags &= ~B_RAM;
135 /*
136 * We do the crit here so that there is no window
137 * between the findblk and the b_usecount increment
138 * below. We opt to keep the crit out of the loop
139 * for efficiency.
140 */
141 crit_enter();
142 for (i = 1; i < maxra; i++) {
143 if (!(tbp = findblk(vp, loffset + i * blksize))) {
144 break;
145 }
146
147 /*
148 * Set another read-ahead mark so we know
149 * to check again.
150 */
151 if (((i % racluster) == (racluster - 1)) ||
152 (i == (maxra - 1)))
153 tbp->b_flags |= B_RAM;
154 }
155 crit_exit();
156 if (i >= maxra) {
157 return 0;
158 }
159 loffset += i * blksize;
160 }
161 reqbp = bp = NULL;
162 } else {
163 off_t firstread = bp->b_loffset;
164 int nblks;
165
166 KASSERT(firstread != NOOFFSET,
167 ("cluster_read: no buffer offset"));
168 if (firstread + totread > filesize)
169 totread = (int)(filesize - firstread);
170 nblks = totread / blksize;
171 if (nblks) {
172 int burstbytes;
173
174 if (nblks > racluster)
175 nblks = racluster;
176
177 error = VOP_BMAP(vp, loffset, &doffset,
178 &burstbytes, NULL, BUF_CMD_READ);
179 if (error)
180 goto single_block_read;
181 if (doffset == NOOFFSET)
182 goto single_block_read;
183 if (burstbytes < blksize * 2)
184 goto single_block_read;
185 if (nblks > burstbytes / blksize)
186 nblks = burstbytes / blksize;
187
188 bp = cluster_rbuild(vp, filesize, loffset,
189 doffset, blksize, nblks, bp, 0);
190 loffset += bp->b_bufsize;
191 } else {
192 single_block_read:
193 /*
194 * if it isn't in the cache, then get a chunk from
195 * disk if sequential, otherwise just get the block.
196 */
197 bp->b_flags |= B_RAM;
198 loffset += blksize;
199 }
200 }
201
202 /*
203 * Handle the synchronous read. This only occurs if B_CACHE was
204 * not set. bp (and rbp) could be either a cluster bp or a normal
205 * bp depending on the what cluster_rbuild() decided to do. If
206 * it is a cluster bp, vfs_busy_pages() has already been called.
207 */
208 if (bp) {
209 #if defined(CLUSTERDEBUG)
210 if (rcluster)
211 kprintf("S(%lld,%d,%d) ",
212 bp->b_loffset, bp->b_bcount, seqcount);
213 #endif
214 bp->b_cmd = BUF_CMD_READ;
215 if ((bp->b_flags & B_CLUSTER) == 0)
216 vfs_busy_pages(vp, bp);
217 bp->b_flags &= ~(B_ERROR|B_INVAL);
218 if ((bp->b_flags & B_ASYNC) || bp->b_bio1.bio_done != NULL)
219 BUF_KERNPROC(bp);
220 vn_strategy(vp, &bp->b_bio1);
221 if (bp->b_flags & B_ERROR) {
222 if ((error = bp->b_error) == 0)
223 error = EIO;
224 } else {
225 error = 0;
226 }
227 }
228
229 /*
230 * If we have been doing sequential I/O, then do some read-ahead.
231 *
232 * Only mess with buffers which we can immediately lock. HAMMER
233 * will do device-readahead irrespective of what the blocks
234 * represent.
235 */
236 rbp = NULL;
237 if (!error &&
238 seqcount &&
239 loffset < origoffset + seqcount * blksize &&
240 loffset + blksize <= filesize
241 ) {
242 int nblksread;
243 int ntoread;
244 int burstbytes;
245 int tmp_error;
246
247 rbp = getblk(vp, loffset, blksize,
248 GETBLK_SZMATCH|GETBLK_NOWAIT, 0);
249 if (rbp == NULL)
250 goto no_read_ahead;
251 if ((rbp->b_flags & B_CACHE)) {
252 bqrelse(rbp);
253 goto no_read_ahead;
254 }
255
256 /*
257 * An error from the read-ahead bmap has nothing to do
258 * with the caller's original request.
259 */
260 tmp_error = VOP_BMAP(vp, loffset, &doffset,
261 &burstbytes, NULL, BUF_CMD_READ);
262 if (tmp_error || doffset == NOOFFSET) {
263 rbp->b_flags |= B_INVAL;
264 brelse(rbp);
265 rbp = NULL;
266 goto no_read_ahead;
267 }
268 ntoread = burstbytes / blksize;
269 nblksread = (totread + blksize - 1) / blksize;
270 if (seqcount < nblksread)
271 seqcount = nblksread;
272 if (ntoread > seqcount)
273 ntoread = seqcount;
274
275 rbp->b_flags |= B_RAM/* | B_AGE*/;
276 if (burstbytes) {
277 rbp = cluster_rbuild(vp, filesize, loffset,
278 doffset, blksize,
279 ntoread, rbp, 1);
280 } else {
281 rbp->b_bio2.bio_offset = doffset;
282 }
283 #if defined(CLUSTERDEBUG)
284 if (rcluster) {
285 if (bp)
286 kprintf("A+(%lld,%d,%lld,%d) ",
287 rbp->b_loffset, rbp->b_bcount,
288 rbp->b_loffset - origoffset,
289 seqcount);
290 else
291 kprintf("A(%lld,%d,%lld,%d) ",
292 rbp->b_loffset, rbp->b_bcount,
293 rbp->b_loffset - origoffset,
294 seqcount);
295 }
296 #endif
297 rbp->b_flags &= ~(B_ERROR|B_INVAL);
298 rbp->b_flags |= B_ASYNC;
299 rbp->b_cmd = BUF_CMD_READ;
300
301 if ((rbp->b_flags & B_CLUSTER) == 0)
302 vfs_busy_pages(vp, rbp);
303 BUF_KERNPROC(rbp); /* B_ASYNC */
304 vn_strategy(vp, &rbp->b_bio1);
305 }
306 no_read_ahead:
307
308 if (reqbp)
309 return (biowait(reqbp));
310 else
311 return (error);
312 }
313
314 /*
315 * If blocks are contiguous on disk, use this to provide clustered
316 * read ahead. We will read as many blocks as possible sequentially
317 * and then parcel them up into logical blocks in the buffer hash table.
318 */
319 static struct buf *
320 cluster_rbuild(struct vnode *vp, off_t filesize, off_t loffset,
321 off_t doffset, int blksize, int run, struct buf *fbp, int doasync)
322 {
323 struct buf *bp, *tbp;
324 off_t boffset;
325 int i, j;
326 int maxiosize = vmaxiosize(vp);
327
328 /*
329 * avoid a division
330 */
331 while (loffset + run * blksize > filesize) {
332 --run;
333 }
334
335 tbp = fbp;
336 tbp->b_bio2.bio_offset = doffset;
337 if((tbp->b_flags & B_MALLOC) ||
338 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1)) {
339 return tbp;
340 }
341
342 bp = trypbuf(&cluster_pbuf_freecnt);
343 if (bp == NULL)
344 return tbp;
345
346 /*
347 * We are synthesizing a buffer out of vm_page_t's, but
348 * if the block size is not page aligned then the starting
349 * address may not be either. Inherit the b_data offset
350 * from the original buffer.
351 */
352 bp->b_data = (char *)((vm_offset_t)bp->b_data |
353 ((vm_offset_t)tbp->b_data & PAGE_MASK));
354 bp->b_flags |= B_ASYNC | B_CLUSTER | B_VMIO;
355 bp->b_cmd = BUF_CMD_READ;
356 bp->b_bio1.bio_done = cluster_callback;
357 bp->b_bio1.bio_caller_info1.cluster_head = NULL;
358 bp->b_bio1.bio_caller_info2.cluster_tail = NULL;
359 bp->b_loffset = loffset;
360 bp->b_bio2.bio_offset = doffset;
361 KASSERT(bp->b_loffset != NOOFFSET,
362 ("cluster_rbuild: no buffer offset"));
363
364 bp->b_bcount = 0;
365 bp->b_bufsize = 0;
366 bp->b_xio.xio_npages = 0;
367
368 for (boffset = doffset, i = 0; i < run; ++i, boffset += blksize) {
369 if (i) {
370 if ((bp->b_xio.xio_npages * PAGE_SIZE) +
371 round_page(blksize) > maxiosize) {
372 break;
373 }
374
375 /*
376 * Shortcut some checks and try to avoid buffers that
377 * would block in the lock. The same checks have to
378 * be made again after we officially get the buffer.
379 */
380 tbp = getblk(vp, loffset + i * blksize, blksize,
381 GETBLK_SZMATCH|GETBLK_NOWAIT, 0);
382 if (tbp == NULL)
383 break;
384 for (j = 0; j < tbp->b_xio.xio_npages; j++) {
385 if (tbp->b_xio.xio_pages[j]->valid)
386 break;
387 }
388 if (j != tbp->b_xio.xio_npages) {
389 bqrelse(tbp);
390 break;
391 }
392
393 /*
394 * Stop scanning if the buffer is fuly 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 (LIST_FIRST(&tbp->b_dep) != NULL &&
403 buf_checkread(tbp))
404 ) {
405 bqrelse(tbp);
406 break;
407 }
408
409 /*
410 * The buffer must be completely invalid in order to
411 * take part in the cluster. If it is partially valid
412 * then we stop.
413 */
414 for (j = 0;j < tbp->b_xio.xio_npages; j++) {
415 if (tbp->b_xio.xio_pages[j]->valid)
416 break;
417 }
418 if (j != tbp->b_xio.xio_npages) {
419 bqrelse(tbp);
420 break;
421 }
422
423 /*
424 * Set a read-ahead mark as appropriate
425 */
426 if (i == 1 || i == (run - 1))
427 tbp->b_flags |= B_RAM;
428
429 /*
430 * Depress the priority of buffers not explicitly
431 * requested.
432 */
433 /* tbp->b_flags |= B_AGE; */
434
435 /*
436 * Set the block number if it isn't set, otherwise
437 * if it is make sure it matches the block number we
438 * expect.
439 */
440 if (tbp->b_bio2.bio_offset == NOOFFSET) {
441 tbp->b_bio2.bio_offset = boffset;
442 } else if (tbp->b_bio2.bio_offset != boffset) {
443 brelse(tbp);
444 break;
445 }
446 }
447 /*
448 * The first buffer is setup async if doasync is specified.
449 * All other buffers in the cluster are setup async. This
450 * way the caller can decide how to deal with the requested
451 * buffer.
452 */
453 if (i || doasync)
454 tbp->b_flags |= B_ASYNC;
455 tbp->b_cmd = BUF_CMD_READ;
456 BUF_KERNPROC(tbp);
457 cluster_append(&bp->b_bio1, tbp);
458 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
459 vm_page_t m;
460 m = tbp->b_xio.xio_pages[j];
461 vm_page_io_start(m);
462 vm_object_pip_add(m->object, 1);
463 if ((bp->b_xio.xio_npages == 0) ||
464 (bp->b_xio.xio_pages[bp->b_xio.xio_npages-1] != m)) {
465 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m;
466 bp->b_xio.xio_npages++;
467 }
468 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL)
469 tbp->b_xio.xio_pages[j] = bogus_page;
470 }
471 /*
472 * XXX shouldn't this be += size for both, like in
473 * cluster_wbuild()?
474 *
475 * Don't inherit tbp->b_bufsize as it may be larger due to
476 * a non-page-aligned size. Instead just aggregate using
477 * 'size'.
478 */
479 if (tbp->b_bcount != blksize)
480 kprintf("warning: tbp->b_bcount wrong %d vs %d\n", tbp->b_bcount, blksize);
481 if (tbp->b_bufsize != blksize)
482 kprintf("warning: tbp->b_bufsize wrong %d vs %d\n", tbp->b_bufsize, blksize);
483 bp->b_bcount += blksize;
484 bp->b_bufsize += blksize;
485 }
486
487 /*
488 * Fully valid pages in the cluster are already good and do not need
489 * to be re-read from disk. Replace the page with bogus_page
490 */
491 for (j = 0; j < bp->b_xio.xio_npages; j++) {
492 if ((bp->b_xio.xio_pages[j]->valid & VM_PAGE_BITS_ALL) ==
493 VM_PAGE_BITS_ALL) {
494 bp->b_xio.xio_pages[j] = bogus_page;
495 }
496 }
497 if (bp->b_bufsize > bp->b_kvasize) {
498 panic("cluster_rbuild: b_bufsize(%d) > b_kvasize(%d)",
499 bp->b_bufsize, bp->b_kvasize);
500 }
501
502 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
503 (vm_page_t *)bp->b_xio.xio_pages, bp->b_xio.xio_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 * The returned bio is &bp->b_bio1
514 */
515 void
516 cluster_callback(struct bio *bio)
517 {
518 struct buf *bp = bio->bio_buf;
519 struct buf *tbp;
520 int error = 0;
521
522 /*
523 * Must propogate errors to all the components. A short read (EOF)
524 * is a critical error.
525 */
526 if (bp->b_flags & B_ERROR) {
527 error = bp->b_error;
528 } else if (bp->b_bcount != bp->b_bufsize) {
529 panic("cluster_callback: unexpected EOF on cluster %p!", bio);
530 }
531
532 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_xio.xio_npages);
533 /*
534 * Move memory from the large cluster buffer into the component
535 * buffers and mark IO as done on these. Since the memory map
536 * is the same, no actual copying is required.
537 */
538 while ((tbp = bio->bio_caller_info1.cluster_head) != NULL) {
539 bio->bio_caller_info1.cluster_head = tbp->b_cluster_next;
540 if (error) {
541 tbp->b_flags |= B_ERROR;
542 tbp->b_error = error;
543 } else {
544 tbp->b_dirtyoff = tbp->b_dirtyend = 0;
545 tbp->b_flags &= ~(B_ERROR|B_INVAL);
546 /*
547 * XXX the bdwrite()/bqrelse() issued during
548 * cluster building clears B_RELBUF (see bqrelse()
549 * comment). If direct I/O was specified, we have
550 * to restore it here to allow the buffer and VM
551 * to be freed.
552 */
553 if (tbp->b_flags & B_DIRECT)
554 tbp->b_flags |= B_RELBUF;
555 }
556 biodone(&tbp->b_bio1);
557 }
558 relpbuf(bp, &cluster_pbuf_freecnt);
559 }
560
561 /*
562 * cluster_wbuild_wb:
563 *
564 * Implement modified write build for cluster.
565 *
566 * write_behind = 0 write behind disabled
567 * write_behind = 1 write behind normal (default)
568 * write_behind = 2 write behind backed-off
569 */
570
571 static __inline int
572 cluster_wbuild_wb(struct vnode *vp, int blksize, off_t start_loffset, int len)
573 {
574 int r = 0;
575
576 switch(write_behind) {
577 case 2:
578 if (start_loffset < len)
579 break;
580 start_loffset -= len;
581 /* fall through */
582 case 1:
583 r = cluster_wbuild(vp, blksize, start_loffset, len);
584 /* fall through */
585 default:
586 /* fall through */
587 break;
588 }
589 return(r);
590 }
591
592 /*
593 * Do clustered write for FFS.
594 *
595 * Three cases:
596 * 1. Write is not sequential (write asynchronously)
597 * Write is sequential:
598 * 2. beginning of cluster - begin cluster
599 * 3. middle of a cluster - add to cluster
600 * 4. end of a cluster - asynchronously write cluster
601 */
602 void
603 cluster_write(struct buf *bp, off_t filesize, int blksize, int seqcount)
604 {
605 struct vnode *vp;
606 off_t loffset;
607 int maxclen, cursize;
608 int async;
609
610 vp = bp->b_vp;
611 if (vp->v_type == VREG)
612 async = vp->v_mount->mnt_flag & MNT_ASYNC;
613 else
614 async = 0;
615 loffset = bp->b_loffset;
616 KASSERT(bp->b_loffset != NOOFFSET,
617 ("cluster_write: no buffer offset"));
618
619 /* Initialize vnode to beginning of file. */
620 if (loffset == 0)
621 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
622
623 if (vp->v_clen == 0 || loffset != vp->v_lastw + blksize ||
624 bp->b_bio2.bio_offset == NOOFFSET ||
625 (bp->b_bio2.bio_offset != vp->v_lasta + blksize)) {
626 maxclen = vmaxiosize(vp);
627 if (vp->v_clen != 0) {
628 /*
629 * Next block is not sequential.
630 *
631 * If we are not writing at end of file, the process
632 * seeked to another point in the file since its last
633 * write, or we have reached our maximum cluster size,
634 * then push the previous cluster. Otherwise try
635 * reallocating to make it sequential.
636 *
637 * Change to algorithm: only push previous cluster if
638 * it was sequential from the point of view of the
639 * seqcount heuristic, otherwise leave the buffer
640 * intact so we can potentially optimize the I/O
641 * later on in the buf_daemon or update daemon
642 * flush.
643 */
644 cursize = vp->v_lastw - vp->v_cstart + blksize;
645 if (bp->b_loffset + blksize != filesize ||
646 loffset != vp->v_lastw + blksize || vp->v_clen <= cursize) {
647 if (!async && seqcount > 0) {
648 cluster_wbuild_wb(vp, blksize,
649 vp->v_cstart, cursize);
650 }
651 } else {
652 struct buf **bpp, **endbp;
653 struct cluster_save *buflist;
654
655 buflist = cluster_collectbufs(vp, bp, blksize);
656 endbp = &buflist->bs_children
657 [buflist->bs_nchildren - 1];
658 if (VOP_REALLOCBLKS(vp, buflist)) {
659 /*
660 * Failed, push the previous cluster
661 * if *really* writing sequentially
662 * in the logical file (seqcount > 1),
663 * otherwise delay it in the hopes that
664 * the low level disk driver can
665 * optimize the write ordering.
666 */
667 for (bpp = buflist->bs_children;
668 bpp < endbp; bpp++)
669 brelse(*bpp);
670 kfree(buflist, M_SEGMENT);
671 if (seqcount > 1) {
672 cluster_wbuild_wb(vp,
673 blksize, vp->v_cstart,
674 cursize);
675 }
676 } else {
677 /*
678 * Succeeded, keep building cluster.
679 */
680 for (bpp = buflist->bs_children;
681 bpp <= endbp; bpp++)
682 bdwrite(*bpp);
683 kfree(buflist, M_SEGMENT);
684 vp->v_lastw = loffset;
685 vp->v_lasta = bp->b_bio2.bio_offset;
686 return;
687 }
688 }
689 }
690 /*
691 * Consider beginning a cluster. If at end of file, make
692 * cluster as large as possible, otherwise find size of
693 * existing cluster.
694 */
695 if ((vp->v_type == VREG) &&
696 bp->b_loffset + blksize != filesize &&
697 (bp->b_bio2.bio_offset == NOOFFSET) &&
698 (VOP_BMAP(vp, loffset, &bp->b_bio2.bio_offset, &maxclen, NULL, BUF_CMD_WRITE) ||
699 bp->b_bio2.bio_offset == NOOFFSET)) {
700 bawrite(bp);
701 vp->v_clen = 0;
702 vp->v_lasta = bp->b_bio2.bio_offset;
703 vp->v_cstart = loffset + blksize;
704 vp->v_lastw = loffset;
705 return;
706 }
707 if (maxclen > blksize)
708 vp->v_clen = maxclen - blksize;
709 else
710 vp->v_clen = 0;
711 if (!async && vp->v_clen == 0) { /* I/O not contiguous */
712 vp->v_cstart = loffset + blksize;
713 bawrite(bp);
714 } else { /* Wait for rest of cluster */
715 vp->v_cstart = loffset;
716 bdwrite(bp);
717 }
718 } else if (loffset == vp->v_cstart + vp->v_clen) {
719 /*
720 * At end of cluster, write it out if seqcount tells us we
721 * are operating sequentially, otherwise let the buf or
722 * update daemon handle it.
723 */
724 bdwrite(bp);
725 if (seqcount > 1)
726 cluster_wbuild_wb(vp, blksize, vp->v_cstart,
727 vp->v_clen + blksize);
728 vp->v_clen = 0;
729 vp->v_cstart = loffset + blksize;
730 } else if (vm_page_count_severe()) {
731 /*
732 * We are low on memory, get it going NOW
733 */
734 bawrite(bp);
735 } else {
736 /*
737 * In the middle of a cluster, so just delay the I/O for now.
738 */
739 bdwrite(bp);
740 }
741 vp->v_lastw = loffset;
742 vp->v_lasta = bp->b_bio2.bio_offset;
743 }
744
745
746 /*
747 * This is an awful lot like cluster_rbuild...wish they could be combined.
748 * The last lbn argument is the current block on which I/O is being
749 * performed. Check to see that it doesn't fall in the middle of
750 * the current block (if last_bp == NULL).
751 */
752 int
753 cluster_wbuild(struct vnode *vp, int blksize, off_t start_loffset, int bytes)
754 {
755 struct buf *bp, *tbp;
756 int i, j;
757 int totalwritten = 0;
758 int maxiosize = vmaxiosize(vp);
759
760 while (bytes > 0) {
761 crit_enter();
762 /*
763 * If the buffer is not delayed-write (i.e. dirty), or it
764 * is delayed-write but either locked or inval, it cannot
765 * partake in the clustered write.
766 */
767 if (((tbp = findblk(vp, start_loffset)) == NULL) ||
768 ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) ||
769 (LIST_FIRST(&tbp->b_dep) != NULL && buf_checkwrite(tbp)) ||
770 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) {
771 start_loffset += blksize;
772 bytes -= blksize;
773 crit_exit();
774 continue;
775 }
776 bremfree(tbp);
777 KKASSERT(tbp->b_cmd == BUF_CMD_DONE);
778 crit_exit();
779
780 /*
781 * Extra memory in the buffer, punt on this buffer.
782 * XXX we could handle this in most cases, but we would
783 * have to push the extra memory down to after our max
784 * possible cluster size and then potentially pull it back
785 * up if the cluster was terminated prematurely--too much
786 * hassle.
787 */
788 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) ||
789 (tbp->b_bcount != tbp->b_bufsize) ||
790 (tbp->b_bcount != blksize) ||
791 (bytes == blksize) ||
792 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) {
793 totalwritten += tbp->b_bufsize;
794 bawrite(tbp);
795 start_loffset += blksize;
796 bytes -= blksize;
797 continue;
798 }
799
800 /*
801 * Set up the pbuf. Track our append point with b_bcount
802 * and b_bufsize. b_bufsize is not used by the device but
803 * our caller uses it to loop clusters and we use it to
804 * detect a premature EOF on the block device.
805 */
806 bp->b_bcount = 0;
807 bp->b_bufsize = 0;
808 bp->b_xio.xio_npages = 0;
809 bp->b_loffset = tbp->b_loffset;
810 bp->b_bio2.bio_offset = tbp->b_bio2.bio_offset;
811
812 /*
813 * We are synthesizing a buffer out of vm_page_t's, but
814 * if the block size is not page aligned then the starting
815 * address may not be either. Inherit the b_data offset
816 * from the original buffer.
817 */
818 bp->b_data = (char *)((vm_offset_t)bp->b_data |
819 ((vm_offset_t)tbp->b_data & PAGE_MASK));
820 bp->b_flags &= ~B_ERROR;
821 bp->b_flags |= B_CLUSTER | B_BNOCLIP |
822 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT));
823 bp->b_bio1.bio_done = cluster_callback;
824 bp->b_bio1.bio_caller_info1.cluster_head = NULL;
825 bp->b_bio1.bio_caller_info2.cluster_tail = NULL;
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 < bytes; (i += blksize), (start_loffset += blksize)) {
832 if (i != 0) { /* If not the first buffer */
833 crit_enter();
834 /*
835 * If the adjacent data is not even in core it
836 * can't need to be written.
837 */
838 if ((tbp = findblk(vp, start_loffset)) == NULL) {
839 crit_exit();
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 (LIST_FIRST(&tbp->b_dep) != NULL && buf_checkwrite(tbp)) ||
856 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) {
857 crit_exit();
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 != blksize) ||
867 ((bp->b_bio2.bio_offset + i) !=
868 tbp->b_bio2.bio_offset) ||
869 ((tbp->b_xio.xio_npages + bp->b_xio.xio_npages) >
870 (maxiosize / PAGE_SIZE))) {
871 BUF_UNLOCK(tbp);
872 crit_exit();
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 KKASSERT(tbp->b_cmd == BUF_CMD_DONE);
882 crit_exit();
883 } /* end of code for non-first buffers only */
884
885 /*
886 * If the IO is via the VM then we do some
887 * special VM hackery (yuck). Since the buffer's
888 * block size may not be page-aligned it is possible
889 * for a page to be shared between two buffers. We
890 * have to get rid of the duplication when building
891 * the cluster.
892 */
893 if (tbp->b_flags & B_VMIO) {
894 vm_page_t m;
895
896 if (i != 0) { /* if not first buffer */
897 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
898 m = tbp->b_xio.xio_pages[j];
899 if (m->flags & PG_BUSY) {
900 bqrelse(tbp);
901 goto finishcluster;
902 }
903 }
904 }
905
906 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
907 m = tbp->b_xio.xio_pages[j];
908 vm_page_io_start(m);
909 vm_object_pip_add(m->object, 1);
910 if ((bp->b_xio.xio_npages == 0) ||
911 (bp->b_xio.xio_pages[bp->b_xio.xio_npages - 1] != m)) {
912 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m;
913 bp->b_xio.xio_npages++;
914 }
915 }
916 }
917 bp->b_bcount += blksize;
918 bp->b_bufsize += blksize;
919
920 crit_enter();
921 bundirty(tbp);
922 tbp->b_flags &= ~B_ERROR;
923 tbp->b_flags |= B_ASYNC;
924 tbp->b_cmd = BUF_CMD_WRITE;
925 crit_exit();
926 BUF_KERNPROC(tbp);
927 cluster_append(&bp->b_bio1, tbp);
928
929 /*
930 * check for latent dependencies to be handled
931 */
932 if (LIST_FIRST(&tbp->b_dep) != NULL)
933 buf_start(tbp);
934 }
935 finishcluster:
936 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
937 (vm_page_t *) bp->b_xio.xio_pages, bp->b_xio.xio_npages);
938 if (bp->b_bufsize > bp->b_kvasize) {
939 panic(
940 "cluster_wbuild: b_bufsize(%d) > b_kvasize(%d)\n",
941 bp->b_bufsize, bp->b_kvasize);
942 }
943 totalwritten += bp->b_bufsize;
944 bp->b_dirtyoff = 0;
945 bp->b_dirtyend = bp->b_bufsize;
946 bp->b_flags |= B_ASYNC;
947 bp->b_cmd = BUF_CMD_WRITE;
948 vfs_busy_pages(vp, bp);
949 bp->b_runningbufspace = bp->b_bufsize;
950 if (bp->b_runningbufspace) {
951 runningbufspace += bp->b_runningbufspace;
952 ++runningbufcount;
953 }
954 BUF_KERNPROC(bp); /* B_ASYNC */
955 vn_strategy(vp, &bp->b_bio1);
956
957 bytes -= i;
958 }
959 return totalwritten;
960 }
961
962 /*
963 * Collect together all the buffers in a cluster.
964 * Plus add one additional buffer.
965 */
966 static struct cluster_save *
967 cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int blksize)
968 {
969 struct cluster_save *buflist;
970 struct buf *bp;
971 off_t loffset;
972 int i, len;
973
974 len = (int)(vp->v_lastw - vp->v_cstart + blksize) / blksize;
975 buflist = kmalloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
976 M_SEGMENT, M_WAITOK);
977 buflist->bs_nchildren = 0;
978 buflist->bs_children = (struct buf **) (buflist + 1);
979 for (loffset = vp->v_cstart, i = 0; i < len; (loffset += blksize), i++) {
980 (void) bread(vp, loffset, last_bp->b_bcount, &bp);
981 buflist->bs_children[i] = bp;
982 if (bp->b_bio2.bio_offset == NOOFFSET) {
983 VOP_BMAP(bp->b_vp, bp->b_loffset,
984 &bp->b_bio2.bio_offset,
985 NULL, NULL, BUF_CMD_WRITE);
986 }
987 }
988 buflist->bs_children[i] = bp = last_bp;
989 if (bp->b_bio2.bio_offset == NOOFFSET) {
990 VOP_BMAP(bp->b_vp, bp->b_loffset, &bp->b_bio2.bio_offset,
991 NULL, NULL, BUF_CMD_WRITE);
992 }
993 buflist->bs_nchildren = i + 1;
994 return (buflist);
995 }
996
997 void
998 cluster_append(struct bio *bio, struct buf *tbp)
999 {
1000 tbp->b_cluster_next = NULL;
1001 if (bio->bio_caller_info1.cluster_head == NULL) {
1002 bio->bio_caller_info1.cluster_head = tbp;
1003 bio->bio_caller_info2.cluster_tail = tbp;
1004 } else {
1005 bio->bio_caller_info2.cluster_tail->b_cluster_next = tbp;
1006 bio->bio_caller_info2.cluster_tail = tbp;
1007 }
1008 }
1009
DragonFly BSD