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Add a vclean_unlocked() call that allows HAMMER to try to get rid of a
[dragonfly.git] / sys / kern / vfs_cluster.c
blob2782801d6a8077beb5430e1f084883ac7a548581
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 1.39 2008/06/20 05:40:04 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 if ((rbp = findblk(vp, loffset)) != NULL) {
248 if (BUF_LOCK(rbp, LK_EXCLUSIVE | LK_NOWAIT)) {
249 goto no_read_ahead;
250 }
251 BUF_UNLOCK(rbp);
252 }
253 rbp = getblk(vp, loffset, blksize, 0, 0);
254 if ((rbp->b_flags & B_CACHE)) {
255 bqrelse(rbp);
256 goto no_read_ahead;
257 }
258
259 /*
260 * An error from the read-ahead bmap has nothing to do
261 * with the caller's original request.
262 */
263 tmp_error = VOP_BMAP(vp, loffset, &doffset,
264 &burstbytes, NULL, BUF_CMD_READ);
265 if (tmp_error || doffset == NOOFFSET) {
266 rbp->b_flags |= B_INVAL;
267 brelse(rbp);
268 rbp = NULL;
269 goto no_read_ahead;
270 }
271 ntoread = burstbytes / blksize;
272 nblksread = (totread + blksize - 1) / blksize;
273 if (seqcount < nblksread)
274 seqcount = nblksread;
275 if (ntoread > seqcount)
276 ntoread = seqcount;
277
278 rbp->b_flags |= B_RAM/* | B_AGE*/;
279 if (burstbytes) {
280 rbp = cluster_rbuild(vp, filesize, loffset,
281 doffset, blksize,
282 ntoread, rbp, 1);
283 } else {
284 rbp->b_bio2.bio_offset = doffset;
285 }
286 #if defined(CLUSTERDEBUG)
287 if (rcluster) {
288 if (bp)
289 kprintf("A+(%lld,%d,%lld,%d) ",
290 rbp->b_loffset, rbp->b_bcount,
291 rbp->b_loffset - origoffset,
292 seqcount);
293 else
294 kprintf("A(%lld,%d,%lld,%d) ",
295 rbp->b_loffset, rbp->b_bcount,
296 rbp->b_loffset - origoffset,
297 seqcount);
298 }
299 #endif
300 rbp->b_flags &= ~(B_ERROR|B_INVAL);
301 rbp->b_flags |= B_ASYNC;
302 rbp->b_cmd = BUF_CMD_READ;
303
304 if ((rbp->b_flags & B_CLUSTER) == 0)
305 vfs_busy_pages(vp, rbp);
306 BUF_KERNPROC(rbp); /* B_ASYNC */
307 vn_strategy(vp, &rbp->b_bio1);
308 }
309 no_read_ahead:
310
311 if (reqbp)
312 return (biowait(reqbp));
313 else
314 return (error);
315 }
316
317 /*
318 * If blocks are contiguous on disk, use this to provide clustered
319 * read ahead. We will read as many blocks as possible sequentially
320 * and then parcel them up into logical blocks in the buffer hash table.
321 */
322 static struct buf *
323 cluster_rbuild(struct vnode *vp, off_t filesize, off_t loffset,
324 off_t doffset, int blksize, int run, struct buf *fbp, int doasync)
325 {
326 struct buf *bp, *tbp;
327 off_t boffset;
328 int i, j;
329 int maxiosize = vmaxiosize(vp);
330
331 /*
332 * avoid a division
333 */
334 while (loffset + run * blksize > filesize) {
335 --run;
336 }
337
338 tbp = fbp;
339 tbp->b_bio2.bio_offset = doffset;
340 if((tbp->b_flags & B_MALLOC) ||
341 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1)) {
342 return tbp;
343 }
344
345 bp = trypbuf(&cluster_pbuf_freecnt);
346 if (bp == NULL)
347 return tbp;
348
349 /*
350 * We are synthesizing a buffer out of vm_page_t's, but
351 * if the block size is not page aligned then the starting
352 * address may not be either. Inherit the b_data offset
353 * from the original buffer.
354 */
355 bp->b_data = (char *)((vm_offset_t)bp->b_data |
356 ((vm_offset_t)tbp->b_data & PAGE_MASK));
357 bp->b_flags |= B_ASYNC | B_CLUSTER | B_VMIO;
358 bp->b_cmd = BUF_CMD_READ;
359 bp->b_bio1.bio_done = cluster_callback;
360 bp->b_bio1.bio_caller_info1.cluster_head = NULL;
361 bp->b_bio1.bio_caller_info2.cluster_tail = NULL;
362 bp->b_loffset = loffset;
363 bp->b_bio2.bio_offset = doffset;
364 KASSERT(bp->b_loffset != NOOFFSET,
365 ("cluster_rbuild: no buffer offset"));
366
367 bp->b_bcount = 0;
368 bp->b_bufsize = 0;
369 bp->b_xio.xio_npages = 0;
370
371 for (boffset = doffset, i = 0; i < run; ++i, boffset += blksize) {
372 if (i) {
373 if ((bp->b_xio.xio_npages * PAGE_SIZE) +
374 round_page(blksize) > maxiosize) {
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 = findblk(vp, loffset + i * blksize)) != NULL) {
384 if (BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT))
385 break;
386 BUF_UNLOCK(tbp);
387
388 for (j = 0; j < tbp->b_xio.xio_npages; j++) {
389 if (tbp->b_xio.xio_pages[j]->valid)
390 break;
391 }
392
393 if (j != tbp->b_xio.xio_npages)
394 break;
395
396 if (tbp->b_bcount != blksize)
397 break;
398 }
399
400 tbp = getblk(vp, loffset + i * blksize, blksize, 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 (LIST_FIRST(&tbp->b_dep) != NULL &&
412 buf_checkread(tbp))
413 ) {
414 bqrelse(tbp);
415 break;
416 }
417
418 /*
419 * The buffer must be completely invalid in order to
420 * take part in the cluster. If it is partially valid
421 * then we stop.
422 */
423 for (j = 0;j < tbp->b_xio.xio_npages; j++) {
424 if (tbp->b_xio.xio_pages[j]->valid)
425 break;
426 }
427 if (j != tbp->b_xio.xio_npages) {
428 bqrelse(tbp);
429 break;
430 }
431
432 /*
433 * Set a read-ahead mark as appropriate
434 */
435 if (i == 1 || i == (run - 1))
436 tbp->b_flags |= B_RAM;
437
438 /*
439 * Depress the priority of buffers not explicitly
440 * requested.
441 */
442 /* tbp->b_flags |= B_AGE; */
443
444 /*
445 * Set the block number if it isn't set, otherwise
446 * if it is make sure it matches the block number we
447 * expect.
448 */
449 if (tbp->b_bio2.bio_offset == NOOFFSET) {
450 tbp->b_bio2.bio_offset = boffset;
451 } else if (tbp->b_bio2.bio_offset != boffset) {
452 brelse(tbp);
453 break;
454 }
455 }
456 /*
457 * The first buffer is setup async if doasync is specified.
458 * All other buffers in the cluster are setup async. This
459 * way the caller can decide how to deal with the requested
460 * buffer.
461 */
462 if (i || doasync)
463 tbp->b_flags |= B_ASYNC;
464 tbp->b_cmd = BUF_CMD_READ;
465 BUF_KERNPROC(tbp);
466 cluster_append(&bp->b_bio1, tbp);
467 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
468 vm_page_t m;
469 m = tbp->b_xio.xio_pages[j];
470 vm_page_io_start(m);
471 vm_object_pip_add(m->object, 1);
472 if ((bp->b_xio.xio_npages == 0) ||
473 (bp->b_xio.xio_pages[bp->b_xio.xio_npages-1] != m)) {
474 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m;
475 bp->b_xio.xio_npages++;
476 }
477 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL)
478 tbp->b_xio.xio_pages[j] = bogus_page;
479 }
480 /*
481 * XXX shouldn't this be += size for both, like in
482 * cluster_wbuild()?
483 *
484 * Don't inherit tbp->b_bufsize as it may be larger due to
485 * a non-page-aligned size. Instead just aggregate using
486 * 'size'.
487 */
488 if (tbp->b_bcount != blksize)
489 kprintf("warning: tbp->b_bcount wrong %d vs %d\n", tbp->b_bcount, blksize);
490 if (tbp->b_bufsize != blksize)
491 kprintf("warning: tbp->b_bufsize wrong %d vs %d\n", tbp->b_bufsize, blksize);
492 bp->b_bcount += blksize;
493 bp->b_bufsize += blksize;
494 }
495
496 /*
497 * Fully valid pages in the cluster are already good and do not need
498 * to be re-read from disk. Replace the page with bogus_page
499 */
500 for (j = 0; j < bp->b_xio.xio_npages; j++) {
501 if ((bp->b_xio.xio_pages[j]->valid & VM_PAGE_BITS_ALL) ==
502 VM_PAGE_BITS_ALL) {
503 bp->b_xio.xio_pages[j] = bogus_page;
504 }
505 }
506 if (bp->b_bufsize > bp->b_kvasize) {
507 panic("cluster_rbuild: b_bufsize(%d) > b_kvasize(%d)",
508 bp->b_bufsize, bp->b_kvasize);
509 }
510
511 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
512 (vm_page_t *)bp->b_xio.xio_pages, bp->b_xio.xio_npages);
513 return (bp);
514 }
515
516 /*
517 * Cleanup after a clustered read or write.
518 * This is complicated by the fact that any of the buffers might have
519 * extra memory (if there were no empty buffer headers at allocbuf time)
520 * that we will need to shift around.
521 *
522 * The returned bio is &bp->b_bio1
523 */
524 void
525 cluster_callback(struct bio *bio)
526 {
527 struct buf *bp = bio->bio_buf;
528 struct buf *tbp;
529 int error = 0;
530
531 /*
532 * Must propogate errors to all the components. A short read (EOF)
533 * is a critical error.
534 */
535 if (bp->b_flags & B_ERROR) {
536 error = bp->b_error;
537 } else if (bp->b_bcount != bp->b_bufsize) {
538 panic("cluster_callback: unexpected EOF on cluster %p!", bio);
539 }
540
541 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_xio.xio_npages);
542 /*
543 * Move memory from the large cluster buffer into the component
544 * buffers and mark IO as done on these. Since the memory map
545 * is the same, no actual copying is required.
546 */
547 while ((tbp = bio->bio_caller_info1.cluster_head) != NULL) {
548 bio->bio_caller_info1.cluster_head = tbp->b_cluster_next;
549 if (error) {
550 tbp->b_flags |= B_ERROR;
551 tbp->b_error = error;
552 } else {
553 tbp->b_dirtyoff = tbp->b_dirtyend = 0;
554 tbp->b_flags &= ~(B_ERROR|B_INVAL);
555 /*
556 * XXX the bdwrite()/bqrelse() issued during
557 * cluster building clears B_RELBUF (see bqrelse()
558 * comment). If direct I/O was specified, we have
559 * to restore it here to allow the buffer and VM
560 * to be freed.
561 */
562 if (tbp->b_flags & B_DIRECT)
563 tbp->b_flags |= B_RELBUF;
564 }
565 biodone(&tbp->b_bio1);
566 }
567 relpbuf(bp, &cluster_pbuf_freecnt);
568 }
569
570 /*
571 * cluster_wbuild_wb:
572 *
573 * Implement modified write build for cluster.
574 *
575 * write_behind = 0 write behind disabled
576 * write_behind = 1 write behind normal (default)
577 * write_behind = 2 write behind backed-off
578 */
579
580 static __inline int
581 cluster_wbuild_wb(struct vnode *vp, int blksize, off_t start_loffset, int len)
582 {
583 int r = 0;
584
585 switch(write_behind) {
586 case 2:
587 if (start_loffset < len)
588 break;
589 start_loffset -= len;
590 /* fall through */
591 case 1:
592 r = cluster_wbuild(vp, blksize, start_loffset, len);
593 /* fall through */
594 default:
595 /* fall through */
596 break;
597 }
598 return(r);
599 }
600
601 /*
602 * Do clustered write for FFS.
603 *
604 * Three cases:
605 * 1. Write is not sequential (write asynchronously)
606 * Write is sequential:
607 * 2. beginning of cluster - begin cluster
608 * 3. middle of a cluster - add to cluster
609 * 4. end of a cluster - asynchronously write cluster
610 */
611 void
612 cluster_write(struct buf *bp, off_t filesize, int blksize, int seqcount)
613 {
614 struct vnode *vp;
615 off_t loffset;
616 int maxclen, cursize;
617 int async;
618
619 vp = bp->b_vp;
620 if (vp->v_type == VREG)
621 async = vp->v_mount->mnt_flag & MNT_ASYNC;
622 else
623 async = 0;
624 loffset = bp->b_loffset;
625 KASSERT(bp->b_loffset != NOOFFSET,
626 ("cluster_write: no buffer offset"));
627
628 /* Initialize vnode to beginning of file. */
629 if (loffset == 0)
630 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
631
632 if (vp->v_clen == 0 || loffset != vp->v_lastw + blksize ||
633 bp->b_bio2.bio_offset == NOOFFSET ||
634 (bp->b_bio2.bio_offset != vp->v_lasta + blksize)) {
635 maxclen = vmaxiosize(vp);
636 if (vp->v_clen != 0) {
637 /*
638 * Next block is not sequential.
639 *
640 * If we are not writing at end of file, the process
641 * seeked to another point in the file since its last
642 * write, or we have reached our maximum cluster size,
643 * then push the previous cluster. Otherwise try
644 * reallocating to make it sequential.
645 *
646 * Change to algorithm: only push previous cluster if
647 * it was sequential from the point of view of the
648 * seqcount heuristic, otherwise leave the buffer
649 * intact so we can potentially optimize the I/O
650 * later on in the buf_daemon or update daemon
651 * flush.
652 */
653 cursize = vp->v_lastw - vp->v_cstart + blksize;
654 if (bp->b_loffset + blksize != filesize ||
655 loffset != vp->v_lastw + blksize || vp->v_clen <= cursize) {
656 if (!async && seqcount > 0) {
657 cluster_wbuild_wb(vp, blksize,
658 vp->v_cstart, cursize);
659 }
660 } else {
661 struct buf **bpp, **endbp;
662 struct cluster_save *buflist;
663
664 buflist = cluster_collectbufs(vp, bp, blksize);
665 endbp = &buflist->bs_children
666 [buflist->bs_nchildren - 1];
667 if (VOP_REALLOCBLKS(vp, buflist)) {
668 /*
669 * Failed, push the previous cluster
670 * if *really* writing sequentially
671 * in the logical file (seqcount > 1),
672 * otherwise delay it in the hopes that
673 * the low level disk driver can
674 * optimize the write ordering.
675 */
676 for (bpp = buflist->bs_children;
677 bpp < endbp; bpp++)
678 brelse(*bpp);
679 kfree(buflist, M_SEGMENT);
680 if (seqcount > 1) {
681 cluster_wbuild_wb(vp,
682 blksize, vp->v_cstart,
683 cursize);
684 }
685 } else {
686 /*
687 * Succeeded, keep building cluster.
688 */
689 for (bpp = buflist->bs_children;
690 bpp <= endbp; bpp++)
691 bdwrite(*bpp);
692 kfree(buflist, M_SEGMENT);
693 vp->v_lastw = loffset;
694 vp->v_lasta = bp->b_bio2.bio_offset;
695 return;
696 }
697 }
698 }
699 /*
700 * Consider beginning a cluster. If at end of file, make
701 * cluster as large as possible, otherwise find size of
702 * existing cluster.
703 */
704 if ((vp->v_type == VREG) &&
705 bp->b_loffset + blksize != filesize &&
706 (bp->b_bio2.bio_offset == NOOFFSET) &&
707 (VOP_BMAP(vp, loffset, &bp->b_bio2.bio_offset, &maxclen, NULL, BUF_CMD_WRITE) ||
708 bp->b_bio2.bio_offset == NOOFFSET)) {
709 bawrite(bp);
710 vp->v_clen = 0;
711 vp->v_lasta = bp->b_bio2.bio_offset;
712 vp->v_cstart = loffset + blksize;
713 vp->v_lastw = loffset;
714 return;
715 }
716 if (maxclen > blksize)
717 vp->v_clen = maxclen - blksize;
718 else
719 vp->v_clen = 0;
720 if (!async && vp->v_clen == 0) { /* I/O not contiguous */
721 vp->v_cstart = loffset + blksize;
722 bawrite(bp);
723 } else { /* Wait for rest of cluster */
724 vp->v_cstart = loffset;
725 bdwrite(bp);
726 }
727 } else if (loffset == vp->v_cstart + vp->v_clen) {
728 /*
729 * At end of cluster, write it out if seqcount tells us we
730 * are operating sequentially, otherwise let the buf or
731 * update daemon handle it.
732 */
733 bdwrite(bp);
734 if (seqcount > 1)
735 cluster_wbuild_wb(vp, blksize, vp->v_cstart,
736 vp->v_clen + blksize);
737 vp->v_clen = 0;
738 vp->v_cstart = loffset + blksize;
739 } else if (vm_page_count_severe()) {
740 /*
741 * We are low on memory, get it going NOW
742 */
743 bawrite(bp);
744 } else {
745 /*
746 * In the middle of a cluster, so just delay the I/O for now.
747 */
748 bdwrite(bp);
749 }
750 vp->v_lastw = loffset;
751 vp->v_lasta = bp->b_bio2.bio_offset;
752 }
753
754
755 /*
756 * This is an awful lot like cluster_rbuild...wish they could be combined.
757 * The last lbn argument is the current block on which I/O is being
758 * performed. Check to see that it doesn't fall in the middle of
759 * the current block (if last_bp == NULL).
760 */
761 int
762 cluster_wbuild(struct vnode *vp, int blksize, off_t start_loffset, int bytes)
763 {
764 struct buf *bp, *tbp;
765 int i, j;
766 int totalwritten = 0;
767 int maxiosize = vmaxiosize(vp);
768
769 while (bytes > 0) {
770 crit_enter();
771 /*
772 * If the buffer is not delayed-write (i.e. dirty), or it
773 * is delayed-write but either locked or inval, it cannot
774 * partake in the clustered write.
775 */
776 if (((tbp = findblk(vp, start_loffset)) == NULL) ||
777 ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) ||
778 (LIST_FIRST(&tbp->b_dep) != NULL && buf_checkwrite(tbp)) ||
779 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) {
780 start_loffset += blksize;
781 bytes -= blksize;
782 crit_exit();
783 continue;
784 }
785 bremfree(tbp);
786 KKASSERT(tbp->b_cmd == BUF_CMD_DONE);
787 crit_exit();
788
789 /*
790 * Extra memory in the buffer, punt on this buffer.
791 * XXX we could handle this in most cases, but we would
792 * have to push the extra memory down to after our max
793 * possible cluster size and then potentially pull it back
794 * up if the cluster was terminated prematurely--too much
795 * hassle.
796 */
797 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) ||
798 (tbp->b_bcount != tbp->b_bufsize) ||
799 (tbp->b_bcount != blksize) ||
800 (bytes == blksize) ||
801 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) {
802 totalwritten += tbp->b_bufsize;
803 bawrite(tbp);
804 start_loffset += blksize;
805 bytes -= blksize;
806 continue;
807 }
808
809 /*
810 * Set up the pbuf. Track our append point with b_bcount
811 * and b_bufsize. b_bufsize is not used by the device but
812 * our caller uses it to loop clusters and we use it to
813 * detect a premature EOF on the block device.
814 */
815 bp->b_bcount = 0;
816 bp->b_bufsize = 0;
817 bp->b_xio.xio_npages = 0;
818 bp->b_loffset = tbp->b_loffset;
819 bp->b_bio2.bio_offset = tbp->b_bio2.bio_offset;
820
821 /*
822 * We are synthesizing a buffer out of vm_page_t's, but
823 * if the block size is not page aligned then the starting
824 * address may not be either. Inherit the b_data offset
825 * from the original buffer.
826 */
827 bp->b_data = (char *)((vm_offset_t)bp->b_data |
828 ((vm_offset_t)tbp->b_data & PAGE_MASK));
829 bp->b_flags &= ~B_ERROR;
830 bp->b_flags |= B_CLUSTER | B_BNOCLIP |
831 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT));
832 bp->b_bio1.bio_done = cluster_callback;
833 bp->b_bio1.bio_caller_info1.cluster_head = NULL;
834 bp->b_bio1.bio_caller_info2.cluster_tail = NULL;
835 /*
836 * From this location in the file, scan forward to see
837 * if there are buffers with adjacent data that need to
838 * be written as well.
839 */
840 for (i = 0; i < bytes; (i += blksize), (start_loffset += blksize)) {
841 if (i != 0) { /* If not the first buffer */
842 crit_enter();
843 /*
844 * If the adjacent data is not even in core it
845 * can't need to be written.
846 */
847 if ((tbp = findblk(vp, start_loffset)) == NULL) {
848 crit_exit();
849 break;
850 }
851
852 /*
853 * If it IS in core, but has different
854 * characteristics, or is locked (which
855 * means it could be undergoing a background
856 * I/O or be in a weird state), then don't
857 * cluster with it.
858 */
859 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK |
860 B_INVAL | B_DELWRI | B_NEEDCOMMIT))
861 != (B_DELWRI | B_CLUSTEROK |
862 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) ||
863 (tbp->b_flags & B_LOCKED) ||
864 (LIST_FIRST(&tbp->b_dep) != NULL && buf_checkwrite(tbp)) ||
865 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) {
866 crit_exit();
867 break;
868 }
869
870 /*
871 * Check that the combined cluster
872 * would make sense with regard to pages
873 * and would not be too large
874 */
875 if ((tbp->b_bcount != blksize) ||
876 ((bp->b_bio2.bio_offset + i) !=
877 tbp->b_bio2.bio_offset) ||
878 ((tbp->b_xio.xio_npages + bp->b_xio.xio_npages) >
879 (maxiosize / PAGE_SIZE))) {
880 BUF_UNLOCK(tbp);
881 crit_exit();
882 break;
883 }
884 /*
885 * Ok, it's passed all the tests,
886 * so remove it from the free list
887 * and mark it busy. We will use it.
888 */
889 bremfree(tbp);
890 KKASSERT(tbp->b_cmd == BUF_CMD_DONE);
891 crit_exit();
892 } /* end of code for non-first buffers only */
893
894 /*
895 * If the IO is via the VM then we do some
896 * special VM hackery (yuck). Since the buffer's
897 * block size may not be page-aligned it is possible
898 * for a page to be shared between two buffers. We
899 * have to get rid of the duplication when building
900 * the cluster.
901 */
902 if (tbp->b_flags & B_VMIO) {
903 vm_page_t m;
904
905 if (i != 0) { /* if not first buffer */
906 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
907 m = tbp->b_xio.xio_pages[j];
908 if (m->flags & PG_BUSY) {
909 bqrelse(tbp);
910 goto finishcluster;
911 }
912 }
913 }
914
915 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
916 m = tbp->b_xio.xio_pages[j];
917 vm_page_io_start(m);
918 vm_object_pip_add(m->object, 1);
919 if ((bp->b_xio.xio_npages == 0) ||
920 (bp->b_xio.xio_pages[bp->b_xio.xio_npages - 1] != m)) {
921 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m;
922 bp->b_xio.xio_npages++;
923 }
924 }
925 }
926 bp->b_bcount += blksize;
927 bp->b_bufsize += blksize;
928
929 crit_enter();
930 bundirty(tbp);
931 tbp->b_flags &= ~B_ERROR;
932 tbp->b_flags |= B_ASYNC;
933 tbp->b_cmd = BUF_CMD_WRITE;
934 crit_exit();
935 BUF_KERNPROC(tbp);
936 cluster_append(&bp->b_bio1, tbp);
937
938 /*
939 * check for latent dependencies to be handled
940 */
941 if (LIST_FIRST(&tbp->b_dep) != NULL)
942 buf_start(tbp);
943 }
944 finishcluster:
945 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
946 (vm_page_t *) bp->b_xio.xio_pages, bp->b_xio.xio_npages);
947 if (bp->b_bufsize > bp->b_kvasize) {
948 panic(
949 "cluster_wbuild: b_bufsize(%d) > b_kvasize(%d)\n",
950 bp->b_bufsize, bp->b_kvasize);
951 }
952 totalwritten += bp->b_bufsize;
953 bp->b_dirtyoff = 0;
954 bp->b_dirtyend = bp->b_bufsize;
955 bp->b_flags |= B_ASYNC;
956 bp->b_cmd = BUF_CMD_WRITE;
957 vfs_busy_pages(vp, bp);
958 bp->b_runningbufspace = bp->b_bufsize;
959 if (bp->b_runningbufspace) {
960 runningbufspace += bp->b_runningbufspace;
961 ++runningbufcount;
962 }
963 BUF_KERNPROC(bp); /* B_ASYNC */
964 vn_strategy(vp, &bp->b_bio1);
965
966 bytes -= i;
967 }
968 return totalwritten;
969 }
970
971 /*
972 * Collect together all the buffers in a cluster.
973 * Plus add one additional buffer.
974 */
975 static struct cluster_save *
976 cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int blksize)
977 {
978 struct cluster_save *buflist;
979 struct buf *bp;
980 off_t loffset;
981 int i, len;
982
983 len = (int)(vp->v_lastw - vp->v_cstart + blksize) / blksize;
984 buflist = kmalloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
985 M_SEGMENT, M_WAITOK);
986 buflist->bs_nchildren = 0;
987 buflist->bs_children = (struct buf **) (buflist + 1);
988 for (loffset = vp->v_cstart, i = 0; i < len; (loffset += blksize), i++) {
989 (void) bread(vp, loffset, last_bp->b_bcount, &bp);
990 buflist->bs_children[i] = bp;
991 if (bp->b_bio2.bio_offset == NOOFFSET) {
992 VOP_BMAP(bp->b_vp, bp->b_loffset,
993 &bp->b_bio2.bio_offset,
994 NULL, NULL, BUF_CMD_WRITE);
995 }
996 }
997 buflist->bs_children[i] = bp = last_bp;
998 if (bp->b_bio2.bio_offset == NOOFFSET) {
999 VOP_BMAP(bp->b_vp, bp->b_loffset, &bp->b_bio2.bio_offset,
1000 NULL, NULL, BUF_CMD_WRITE);
1001 }
1002 buflist->bs_nchildren = i + 1;
1003 return (buflist);
1004 }
1005
1006 void
1007 cluster_append(struct bio *bio, struct buf *tbp)
1008 {
1009 tbp->b_cluster_next = NULL;
1010 if (bio->bio_caller_info1.cluster_head == NULL) {
1011 bio->bio_caller_info1.cluster_head = tbp;
1012 bio->bio_caller_info2.cluster_tail = tbp;
1013 } else {
1014 bio->bio_caller_info2.cluster_tail->b_cluster_next = tbp;
1015 bio->bio_caller_info2.cluster_tail = tbp;
1016 }
1017 }
1018
DragonFly BSD