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Remove advertising clause from all that isn't contrib or userland bin.
[dragonfly.git] / sys / kern / vfs_cluster.c
blob1e9e33dd1f10bc6d15d70d9bd9d15af8c0ec090e
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 * $FreeBSD: src/sys/kern/vfs_cluster.c,v 1.92.2.9 2001/11/18 07:10:59 dillon Exp $
33 * $DragonFly: src/sys/kern/vfs_cluster.c,v 1.40 2008/07/14 03:09:00 dillon Exp $
34 */
35
36 #include "opt_debug_cluster.h"
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
41 #include <sys/proc.h>
42 #include <sys/buf.h>
43 #include <sys/vnode.h>
44 #include <sys/malloc.h>
45 #include <sys/mount.h>
46 #include <sys/resourcevar.h>
47 #include <sys/vmmeter.h>
48 #include <vm/vm.h>
49 #include <vm/vm_object.h>
50 #include <vm/vm_page.h>
51 #include <sys/sysctl.h>
52
53 #include <sys/buf2.h>
54 #include <vm/vm_page2.h>
55
56 #include <machine/limits.h>
57
58 #if defined(CLUSTERDEBUG)
59 #include <sys/sysctl.h>
60 static int rcluster= 0;
61 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, "");
62 #endif
63
64 static MALLOC_DEFINE(M_SEGMENT, "cluster_save", "cluster_save buffer");
65
66 static struct cluster_save *
67 cluster_collectbufs (struct vnode *vp, struct buf *last_bp,
68 int blksize);
69 static struct buf *
70 cluster_rbuild (struct vnode *vp, off_t filesize, off_t loffset,
71 off_t doffset, int blksize, int run,
72 struct buf *fbp);
73 static void cluster_callback (struct bio *);
74 static void cluster_setram (struct buf *);
75 static int cluster_wbuild(struct vnode *vp, struct buf **bpp, int blksize,
76 off_t start_loffset, int bytes);
77
78 static int write_behind = 1;
79 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0,
80 "Cluster write-behind setting");
81 static quad_t write_behind_minfilesize = 10 * 1024 * 1024;
82 SYSCTL_QUAD(_vfs, OID_AUTO, write_behind_minfilesize, CTLFLAG_RW,
83 &write_behind_minfilesize, 0, "Cluster write-behind setting");
84 static int max_readahead = 2 * 1024 * 1024;
85 SYSCTL_INT(_vfs, OID_AUTO, max_readahead, CTLFLAG_RW, &max_readahead, 0,
86 "Limit in bytes for desired cluster read-ahead");
87
88 extern vm_page_t bogus_page;
89
90 extern int cluster_pbuf_freecnt;
91
92 /*
93 * This replaces bread.
94 *
95 * filesize - read-ahead @ blksize will not cross this boundary
96 * loffset - loffset for returned *bpp
97 * blksize - blocksize for returned *bpp and read-ahead bps
98 * minreq - minimum (not a hard minimum) in bytes, typically reflects
99 * a higher level uio resid.
100 * maxreq - maximum (sequential heuristic) in bytes (highet typ ~2MB)
101 * bpp - return buffer (*bpp) for (loffset,blksize)
102 */
103 int
104 cluster_readx(struct vnode *vp, off_t filesize, off_t loffset,
105 int blksize, size_t minreq, size_t maxreq, struct buf **bpp)
106 {
107 struct buf *bp, *rbp, *reqbp;
108 off_t origoffset;
109 off_t doffset;
110 int error;
111 int i;
112 int maxra;
113 int maxrbuild;
114
115 error = 0;
116
117 /*
118 * Calculate the desired read-ahead in blksize'd blocks (maxra).
119 * To do this we calculate maxreq.
120 *
121 * maxreq typically starts out as a sequential heuristic. If the
122 * high level uio/resid is bigger (minreq), we pop maxreq up to
123 * minreq. This represents the case where random I/O is being
124 * performed by the userland is issuing big read()'s.
125 *
126 * Then we limit maxreq to max_readahead to ensure it is a reasonable
127 * value.
128 *
129 * Finally we must ensure that (loffset + maxreq) does not cross the
130 * boundary (filesize) for the current blocksize. If we allowed it
131 * to cross we could end up with buffers past the boundary with the
132 * wrong block size (HAMMER large-data areas use mixed block sizes).
133 * minreq is also absolutely limited to filesize.
134 */
135 if (maxreq < minreq)
136 maxreq = minreq;
137 /* minreq not used beyond this point */
138
139 if (maxreq > max_readahead) {
140 maxreq = max_readahead;
141 if (maxreq > 16 * 1024 * 1024)
142 maxreq = 16 * 1024 * 1024;
143 }
144 if (maxreq < blksize)
145 maxreq = blksize;
146 if (loffset + maxreq > filesize) {
147 if (loffset > filesize)
148 maxreq = 0;
149 else
150 maxreq = filesize - loffset;
151 }
152
153 maxra = (int)(maxreq / blksize);
154
155 /*
156 * Get the requested block.
157 */
158 if (*bpp)
159 reqbp = bp = *bpp;
160 else
161 *bpp = reqbp = bp = getblk(vp, loffset, blksize, 0, 0);
162 origoffset = loffset;
163
164 /*
165 * Calculate the maximum cluster size for a single I/O, used
166 * by cluster_rbuild().
167 */
168 maxrbuild = vmaxiosize(vp) / blksize;
169
170 /*
171 * if it is in the cache, then check to see if the reads have been
172 * sequential. If they have, then try some read-ahead, otherwise
173 * back-off on prospective read-aheads.
174 */
175 if (bp->b_flags & B_CACHE) {
176 /*
177 * Not sequential, do not do any read-ahead
178 */
179 if (maxra <= 1)
180 return 0;
181
182 /*
183 * No read-ahead mark, do not do any read-ahead
184 * yet.
185 */
186 if ((bp->b_flags & B_RAM) == 0)
187 return 0;
188
189 /*
190 * We hit a read-ahead-mark, figure out how much read-ahead
191 * to do (maxra) and where to start (loffset).
192 *
193 * Shortcut the scan. Typically the way this works is that
194 * we've built up all the blocks inbetween except for the
195 * last in previous iterations, so if the second-to-last
196 * block is present we just skip ahead to it.
197 *
198 * This algorithm has O(1) cpu in the steady state no
199 * matter how large maxra is.
200 */
201 bp->b_flags &= ~B_RAM;
202
203 if (findblk(vp, loffset + (maxra - 2) * blksize, FINDBLK_TEST))
204 i = maxra - 1;
205 else
206 i = 1;
207 while (i < maxra) {
208 if (findblk(vp, loffset + i * blksize,
209 FINDBLK_TEST) == NULL) {
210 break;
211 }
212 ++i;
213 }
214
215 /*
216 * We got everything or everything is in the cache, no
217 * point continuing.
218 */
219 if (i >= maxra)
220 return 0;
221
222 /*
223 * Calculate where to start the read-ahead and how much
224 * to do. Generally speaking we want to read-ahead by
225 * (maxra) when we've found a read-ahead mark. We do
226 * not want to reduce maxra here as it will cause
227 * successive read-ahead I/O's to be smaller and smaller.
228 *
229 * However, we have to make sure we don't break the
230 * filesize limitation for the clustered operation.
231 */
232 loffset += i * blksize;
233 reqbp = bp = NULL;
234
235 if (loffset >= filesize)
236 return 0;
237 if (loffset + maxra * blksize > filesize) {
238 maxreq = filesize - loffset;
239 maxra = (int)(maxreq / blksize);
240 }
241 } else {
242 __debugvar off_t firstread = bp->b_loffset;
243 int nblks;
244
245 /*
246 * Set-up synchronous read for bp.
247 */
248 bp->b_cmd = BUF_CMD_READ;
249 bp->b_bio1.bio_done = biodone_sync;
250 bp->b_bio1.bio_flags |= BIO_SYNC;
251
252 KASSERT(firstread != NOOFFSET,
253 ("cluster_read: no buffer offset"));
254
255 /*
256 * nblks is our cluster_rbuild request size, limited
257 * primarily by the device.
258 */
259 if ((nblks = maxra) > maxrbuild)
260 nblks = maxrbuild;
261
262 if (nblks > 1) {
263 int burstbytes;
264
265 error = VOP_BMAP(vp, loffset, &doffset,
266 &burstbytes, NULL, BUF_CMD_READ);
267 if (error)
268 goto single_block_read;
269 if (nblks > burstbytes / blksize)
270 nblks = burstbytes / blksize;
271 if (doffset == NOOFFSET)
272 goto single_block_read;
273 if (nblks <= 1)
274 goto single_block_read;
275
276 bp = cluster_rbuild(vp, filesize, loffset,
277 doffset, blksize, nblks, bp);
278 loffset += bp->b_bufsize;
279 maxra -= bp->b_bufsize / blksize;
280 } else {
281 single_block_read:
282 /*
283 * If it isn't in the cache, then get a chunk from
284 * disk if sequential, otherwise just get the block.
285 */
286 cluster_setram(bp);
287 loffset += blksize;
288 --maxra;
289 }
290 }
291
292 /*
293 * If B_CACHE was not set issue bp. bp will either be an
294 * asynchronous cluster buf or a synchronous single-buf.
295 * If it is a single buf it will be the same as reqbp.
296 *
297 * NOTE: Once an async cluster buf is issued bp becomes invalid.
298 */
299 if (bp) {
300 #if defined(CLUSTERDEBUG)
301 if (rcluster)
302 kprintf("S(%012jx,%d,%d)\n",
303 (intmax_t)bp->b_loffset, bp->b_bcount, maxra);
304 #endif
305 if ((bp->b_flags & B_CLUSTER) == 0)
306 vfs_busy_pages(vp, bp);
307 bp->b_flags &= ~(B_ERROR|B_INVAL);
308 vn_strategy(vp, &bp->b_bio1);
309 error = 0;
310 /* bp invalid now */
311 }
312
313 /*
314 * If we have been doing sequential I/O, then do some read-ahead.
315 * The code above us should have positioned us at the next likely
316 * offset.
317 *
318 * Only mess with buffers which we can immediately lock. HAMMER
319 * will do device-readahead irrespective of what the blocks
320 * represent.
321 */
322 while (error == 0 && maxra > 0) {
323 int burstbytes;
324 int tmp_error;
325 int nblks;
326
327 rbp = getblk(vp, loffset, blksize,
328 GETBLK_SZMATCH|GETBLK_NOWAIT, 0);
329 if (rbp == NULL)
330 goto no_read_ahead;
331 if ((rbp->b_flags & B_CACHE)) {
332 bqrelse(rbp);
333 goto no_read_ahead;
334 }
335
336 /*
337 * An error from the read-ahead bmap has nothing to do
338 * with the caller's original request.
339 */
340 tmp_error = VOP_BMAP(vp, loffset, &doffset,
341 &burstbytes, NULL, BUF_CMD_READ);
342 if (tmp_error || doffset == NOOFFSET) {
343 rbp->b_flags |= B_INVAL;
344 brelse(rbp);
345 rbp = NULL;
346 goto no_read_ahead;
347 }
348 if ((nblks = maxra) > maxrbuild)
349 nblks = maxrbuild;
350 if (nblks > burstbytes / blksize)
351 nblks = burstbytes / blksize;
352
353 /*
354 * rbp: async read
355 */
356 rbp->b_cmd = BUF_CMD_READ;
357 /*rbp->b_flags |= B_AGE*/;
358 cluster_setram(rbp);
359
360 if (nblks > 1) {
361 rbp = cluster_rbuild(vp, filesize, loffset,
362 doffset, blksize,
363 nblks, rbp);
364 } else {
365 rbp->b_bio2.bio_offset = doffset;
366 }
367
368 #if defined(CLUSTERDEBUG)
369 if (rcluster) {
370 if (bp) {
371 kprintf("A+(%012jx,%d,%jd) "
372 "doff=%012jx minr=%zd ra=%d\n",
373 (intmax_t)loffset, rbp->b_bcount,
374 (intmax_t)(loffset - origoffset),
375 (intmax_t)doffset, minreq, maxra);
376 } else {
377 kprintf("A-(%012jx,%d,%jd) "
378 "doff=%012jx minr=%zd ra=%d\n",
379 (intmax_t)rbp->b_loffset, rbp->b_bcount,
380 (intmax_t)(loffset - origoffset),
381 (intmax_t)doffset, minreq, maxra);
382 }
383 }
384 #endif
385 rbp->b_flags &= ~(B_ERROR|B_INVAL);
386
387 if ((rbp->b_flags & B_CLUSTER) == 0)
388 vfs_busy_pages(vp, rbp);
389 BUF_KERNPROC(rbp);
390 loffset += rbp->b_bufsize;
391 maxra -= rbp->b_bufsize / blksize;
392 vn_strategy(vp, &rbp->b_bio1);
393 /* rbp invalid now */
394 }
395
396 /*
397 * Wait for our original buffer to complete its I/O. reqbp will
398 * be NULL if the original buffer was B_CACHE. We are returning
399 * (*bpp) which is the same as reqbp when reqbp != NULL.
400 */
401 no_read_ahead:
402 if (reqbp) {
403 KKASSERT(reqbp->b_bio1.bio_flags & BIO_SYNC);
404 error = biowait(&reqbp->b_bio1, "clurd");
405 }
406 return (error);
407 }
408
409 /*
410 * If blocks are contiguous on disk, use this to provide clustered
411 * read ahead. We will read as many blocks as possible sequentially
412 * and then parcel them up into logical blocks in the buffer hash table.
413 *
414 * This function either returns a cluster buf or it returns fbp. fbp is
415 * already expected to be set up as a synchronous or asynchronous request.
416 *
417 * If a cluster buf is returned it will always be async.
418 */
419 static struct buf *
420 cluster_rbuild(struct vnode *vp, off_t filesize, off_t loffset, off_t doffset,
421 int blksize, int run, struct buf *fbp)
422 {
423 struct buf *bp, *tbp;
424 off_t boffset;
425 int i, j;
426 int maxiosize = vmaxiosize(vp);
427
428 /*
429 * avoid a division
430 */
431 while (loffset + run * blksize > filesize) {
432 --run;
433 }
434
435 tbp = fbp;
436 tbp->b_bio2.bio_offset = doffset;
437 if((tbp->b_flags & B_MALLOC) ||
438 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1)) {
439 return tbp;
440 }
441
442 bp = trypbuf_kva(&cluster_pbuf_freecnt);
443 if (bp == NULL) {
444 return tbp;
445 }
446
447 /*
448 * We are synthesizing a buffer out of vm_page_t's, but
449 * if the block size is not page aligned then the starting
450 * address may not be either. Inherit the b_data offset
451 * from the original buffer.
452 */
453 bp->b_data = (char *)((vm_offset_t)bp->b_data |
454 ((vm_offset_t)tbp->b_data & PAGE_MASK));
455 bp->b_flags |= B_CLUSTER | B_VMIO;
456 bp->b_cmd = BUF_CMD_READ;
457 bp->b_bio1.bio_done = cluster_callback; /* default to async */
458 bp->b_bio1.bio_caller_info1.cluster_head = NULL;
459 bp->b_bio1.bio_caller_info2.cluster_tail = NULL;
460 bp->b_loffset = loffset;
461 bp->b_bio2.bio_offset = doffset;
462 KASSERT(bp->b_loffset != NOOFFSET,
463 ("cluster_rbuild: no buffer offset"));
464
465 bp->b_bcount = 0;
466 bp->b_bufsize = 0;
467 bp->b_xio.xio_npages = 0;
468
469 for (boffset = doffset, i = 0; i < run; ++i, boffset += blksize) {
470 if (i) {
471 if ((bp->b_xio.xio_npages * PAGE_SIZE) +
472 round_page(blksize) > maxiosize) {
473 break;
474 }
475
476 /*
477 * Shortcut some checks and try to avoid buffers that
478 * would block in the lock. The same checks have to
479 * be made again after we officially get the buffer.
480 */
481 tbp = getblk(vp, loffset + i * blksize, blksize,
482 GETBLK_SZMATCH|GETBLK_NOWAIT, 0);
483 if (tbp == NULL)
484 break;
485 for (j = 0; j < tbp->b_xio.xio_npages; j++) {
486 if (tbp->b_xio.xio_pages[j]->valid)
487 break;
488 }
489 if (j != tbp->b_xio.xio_npages) {
490 bqrelse(tbp);
491 break;
492 }
493
494 /*
495 * Stop scanning if the buffer is fuly valid
496 * (marked B_CACHE), or locked (may be doing a
497 * background write), or if the buffer is not
498 * VMIO backed. The clustering code can only deal
499 * with VMIO-backed buffers.
500 */
501 if ((tbp->b_flags & (B_CACHE|B_LOCKED)) ||
502 (tbp->b_flags & B_VMIO) == 0 ||
503 (LIST_FIRST(&tbp->b_dep) != NULL &&
504 buf_checkread(tbp))
505 ) {
506 bqrelse(tbp);
507 break;
508 }
509
510 /*
511 * The buffer must be completely invalid in order to
512 * take part in the cluster. If it is partially valid
513 * then we stop.
514 */
515 for (j = 0;j < tbp->b_xio.xio_npages; j++) {
516 if (tbp->b_xio.xio_pages[j]->valid)
517 break;
518 }
519 if (j != tbp->b_xio.xio_npages) {
520 bqrelse(tbp);
521 break;
522 }
523
524 /*
525 * Set a read-ahead mark as appropriate. Always
526 * set the read-ahead mark at (run - 1). It is
527 * unclear why we were also setting it at i == 1.
528 */
529 if (/*i == 1 ||*/ i == (run - 1))
530 cluster_setram(tbp);
531
532 /*
533 * Depress the priority of buffers not explicitly
534 * requested.
535 */
536 /* tbp->b_flags |= B_AGE; */
537
538 /*
539 * Set the block number if it isn't set, otherwise
540 * if it is make sure it matches the block number we
541 * expect.
542 */
543 if (tbp->b_bio2.bio_offset == NOOFFSET) {
544 tbp->b_bio2.bio_offset = boffset;
545 } else if (tbp->b_bio2.bio_offset != boffset) {
546 brelse(tbp);
547 break;
548 }
549 }
550
551 /*
552 * The passed-in tbp (i == 0) will already be set up for
553 * async or sync operation. All other tbp's acquire in
554 * our loop are set up for async operation.
555 */
556 tbp->b_cmd = BUF_CMD_READ;
557 BUF_KERNPROC(tbp);
558 cluster_append(&bp->b_bio1, tbp);
559 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
560 vm_page_t m;
561
562 m = tbp->b_xio.xio_pages[j];
563 vm_page_busy_wait(m, FALSE, "clurpg");
564 vm_page_io_start(m);
565 vm_page_wakeup(m);
566 vm_object_pip_add(m->object, 1);
567 if ((bp->b_xio.xio_npages == 0) ||
568 (bp->b_xio.xio_pages[bp->b_xio.xio_npages-1] != m)) {
569 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m;
570 bp->b_xio.xio_npages++;
571 }
572 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL)
573 tbp->b_xio.xio_pages[j] = bogus_page;
574 }
575 /*
576 * XXX shouldn't this be += size for both, like in
577 * cluster_wbuild()?
578 *
579 * Don't inherit tbp->b_bufsize as it may be larger due to
580 * a non-page-aligned size. Instead just aggregate using
581 * 'size'.
582 */
583 if (tbp->b_bcount != blksize)
584 kprintf("warning: tbp->b_bcount wrong %d vs %d\n", tbp->b_bcount, blksize);
585 if (tbp->b_bufsize != blksize)
586 kprintf("warning: tbp->b_bufsize wrong %d vs %d\n", tbp->b_bufsize, blksize);
587 bp->b_bcount += blksize;
588 bp->b_bufsize += blksize;
589 }
590
591 /*
592 * Fully valid pages in the cluster are already good and do not need
593 * to be re-read from disk. Replace the page with bogus_page
594 */
595 for (j = 0; j < bp->b_xio.xio_npages; j++) {
596 if ((bp->b_xio.xio_pages[j]->valid & VM_PAGE_BITS_ALL) ==
597 VM_PAGE_BITS_ALL) {
598 bp->b_xio.xio_pages[j] = bogus_page;
599 }
600 }
601 if (bp->b_bufsize > bp->b_kvasize) {
602 panic("cluster_rbuild: b_bufsize(%d) > b_kvasize(%d)",
603 bp->b_bufsize, bp->b_kvasize);
604 }
605 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
606 (vm_page_t *)bp->b_xio.xio_pages, bp->b_xio.xio_npages);
607 BUF_KERNPROC(bp);
608 return (bp);
609 }
610
611 /*
612 * Cleanup after a clustered read or write.
613 * This is complicated by the fact that any of the buffers might have
614 * extra memory (if there were no empty buffer headers at allocbuf time)
615 * that we will need to shift around.
616 *
617 * The returned bio is &bp->b_bio1
618 */
619 void
620 cluster_callback(struct bio *bio)
621 {
622 struct buf *bp = bio->bio_buf;
623 struct buf *tbp;
624 int error = 0;
625
626 /*
627 * Must propogate errors to all the components. A short read (EOF)
628 * is a critical error.
629 */
630 if (bp->b_flags & B_ERROR) {
631 error = bp->b_error;
632 } else if (bp->b_bcount != bp->b_bufsize) {
633 panic("cluster_callback: unexpected EOF on cluster %p!", bio);
634 }
635
636 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_xio.xio_npages);
637 /*
638 * Move memory from the large cluster buffer into the component
639 * buffers and mark IO as done on these. Since the memory map
640 * is the same, no actual copying is required.
641 */
642 while ((tbp = bio->bio_caller_info1.cluster_head) != NULL) {
643 bio->bio_caller_info1.cluster_head = tbp->b_cluster_next;
644 if (error) {
645 tbp->b_flags |= B_ERROR | B_IODEBUG;
646 tbp->b_error = error;
647 } else {
648 tbp->b_dirtyoff = tbp->b_dirtyend = 0;
649 tbp->b_flags &= ~(B_ERROR|B_INVAL);
650 tbp->b_flags |= B_IODEBUG;
651 /*
652 * XXX the bdwrite()/bqrelse() issued during
653 * cluster building clears B_RELBUF (see bqrelse()
654 * comment). If direct I/O was specified, we have
655 * to restore it here to allow the buffer and VM
656 * to be freed.
657 */
658 if (tbp->b_flags & B_DIRECT)
659 tbp->b_flags |= B_RELBUF;
660 }
661 biodone(&tbp->b_bio1);
662 }
663 relpbuf(bp, &cluster_pbuf_freecnt);
664 }
665
666 /*
667 * Implement modified write build for cluster.
668 *
669 * write_behind = 0 write behind disabled
670 * write_behind = 1 write behind normal (default)
671 * write_behind = 2 write behind backed-off
672 *
673 * In addition, write_behind is only activated for files that have
674 * grown past a certain size (default 10MB). Otherwise temporary files
675 * wind up generating a lot of unnecessary disk I/O.
676 */
677 static __inline int
678 cluster_wbuild_wb(struct vnode *vp, int blksize, off_t start_loffset, int len)
679 {
680 int r = 0;
681
682 switch(write_behind) {
683 case 2:
684 if (start_loffset < len)
685 break;
686 start_loffset -= len;
687 /* fall through */
688 case 1:
689 if (vp->v_filesize >= write_behind_minfilesize) {
690 r = cluster_wbuild(vp, NULL, blksize,
691 start_loffset, len);
692 }
693 /* fall through */
694 default:
695 /* fall through */
696 break;
697 }
698 return(r);
699 }
700
701 /*
702 * Do clustered write for FFS.
703 *
704 * Three cases:
705 * 1. Write is not sequential (write asynchronously)
706 * Write is sequential:
707 * 2. beginning of cluster - begin cluster
708 * 3. middle of a cluster - add to cluster
709 * 4. end of a cluster - asynchronously write cluster
710 */
711 void
712 cluster_write(struct buf *bp, off_t filesize, int blksize, int seqcount)
713 {
714 struct vnode *vp;
715 off_t loffset;
716 int maxclen, cursize;
717 int async;
718
719 vp = bp->b_vp;
720 if (vp->v_type == VREG)
721 async = vp->v_mount->mnt_flag & MNT_ASYNC;
722 else
723 async = 0;
724 loffset = bp->b_loffset;
725 KASSERT(bp->b_loffset != NOOFFSET,
726 ("cluster_write: no buffer offset"));
727
728 /* Initialize vnode to beginning of file. */
729 if (loffset == 0)
730 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
731
732 if (vp->v_clen == 0 || loffset != vp->v_lastw + blksize ||
733 bp->b_bio2.bio_offset == NOOFFSET ||
734 (bp->b_bio2.bio_offset != vp->v_lasta + blksize)) {
735 maxclen = vmaxiosize(vp);
736 if (vp->v_clen != 0) {
737 /*
738 * Next block is not sequential.
739 *
740 * If we are not writing at end of file, the process
741 * seeked to another point in the file since its last
742 * write, or we have reached our maximum cluster size,
743 * then push the previous cluster. Otherwise try
744 * reallocating to make it sequential.
745 *
746 * Change to algorithm: only push previous cluster if
747 * it was sequential from the point of view of the
748 * seqcount heuristic, otherwise leave the buffer
749 * intact so we can potentially optimize the I/O
750 * later on in the buf_daemon or update daemon
751 * flush.
752 */
753 cursize = vp->v_lastw - vp->v_cstart + blksize;
754 if (bp->b_loffset + blksize < filesize ||
755 loffset != vp->v_lastw + blksize || vp->v_clen <= cursize) {
756 if (!async && seqcount > 0) {
757 cluster_wbuild_wb(vp, blksize,
758 vp->v_cstart, cursize);
759 }
760 } else {
761 struct buf **bpp, **endbp;
762 struct cluster_save *buflist;
763
764 buflist = cluster_collectbufs(vp, bp, blksize);
765 endbp = &buflist->bs_children
766 [buflist->bs_nchildren - 1];
767 if (VOP_REALLOCBLKS(vp, buflist)) {
768 /*
769 * Failed, push the previous cluster
770 * if *really* writing sequentially
771 * in the logical file (seqcount > 1),
772 * otherwise delay it in the hopes that
773 * the low level disk driver can
774 * optimize the write ordering.
775 */
776 for (bpp = buflist->bs_children;
777 bpp < endbp; bpp++)
778 brelse(*bpp);
779 kfree(buflist, M_SEGMENT);
780 if (seqcount > 1) {
781 cluster_wbuild_wb(vp,
782 blksize, vp->v_cstart,
783 cursize);
784 }
785 } else {
786 /*
787 * Succeeded, keep building cluster.
788 */
789 for (bpp = buflist->bs_children;
790 bpp <= endbp; bpp++)
791 bdwrite(*bpp);
792 kfree(buflist, M_SEGMENT);
793 vp->v_lastw = loffset;
794 vp->v_lasta = bp->b_bio2.bio_offset;
795 return;
796 }
797 }
798 }
799 /*
800 * Consider beginning a cluster. If at end of file, make
801 * cluster as large as possible, otherwise find size of
802 * existing cluster.
803 */
804 if ((vp->v_type == VREG) &&
805 bp->b_loffset + blksize < filesize &&
806 (bp->b_bio2.bio_offset == NOOFFSET) &&
807 (VOP_BMAP(vp, loffset, &bp->b_bio2.bio_offset, &maxclen, NULL, BUF_CMD_WRITE) ||
808 bp->b_bio2.bio_offset == NOOFFSET)) {
809 bdwrite(bp);
810 vp->v_clen = 0;
811 vp->v_lasta = bp->b_bio2.bio_offset;
812 vp->v_cstart = loffset + blksize;
813 vp->v_lastw = loffset;
814 return;
815 }
816 if (maxclen > blksize)
817 vp->v_clen = maxclen - blksize;
818 else
819 vp->v_clen = 0;
820 if (!async && vp->v_clen == 0) { /* I/O not contiguous */
821 vp->v_cstart = loffset + blksize;
822 bdwrite(bp);
823 } else { /* Wait for rest of cluster */
824 vp->v_cstart = loffset;
825 bdwrite(bp);
826 }
827 } else if (loffset == vp->v_cstart + vp->v_clen) {
828 /*
829 * At end of cluster, write it out if seqcount tells us we
830 * are operating sequentially, otherwise let the buf or
831 * update daemon handle it.
832 */
833 bdwrite(bp);
834 if (seqcount > 1)
835 cluster_wbuild_wb(vp, blksize, vp->v_cstart,
836 vp->v_clen + blksize);
837 vp->v_clen = 0;
838 vp->v_cstart = loffset + blksize;
839 } else if (vm_page_count_severe() &&
840 bp->b_loffset + blksize < filesize) {
841 /*
842 * We are low on memory, get it going NOW. However, do not
843 * try to push out a partial block at the end of the file
844 * as this could lead to extremely non-optimal write activity.
845 */
846 bawrite(bp);
847 } else {
848 /*
849 * In the middle of a cluster, so just delay the I/O for now.
850 */
851 bdwrite(bp);
852 }
853 vp->v_lastw = loffset;
854 vp->v_lasta = bp->b_bio2.bio_offset;
855 }
856
857 /*
858 * This is the clustered version of bawrite(). It works similarly to
859 * cluster_write() except I/O on the buffer is guaranteed to occur.
860 */
861 int
862 cluster_awrite(struct buf *bp)
863 {
864 int total;
865
866 /*
867 * Don't bother if it isn't clusterable.
868 */
869 if ((bp->b_flags & B_CLUSTEROK) == 0 ||
870 bp->b_vp == NULL ||
871 (bp->b_vp->v_flag & VOBJBUF) == 0) {
872 total = bp->b_bufsize;
873 bawrite(bp);
874 return (total);
875 }
876
877 total = cluster_wbuild(bp->b_vp, &bp, bp->b_bufsize,
878 bp->b_loffset, vmaxiosize(bp->b_vp));
879 if (bp)
880 bawrite(bp);
881
882 return total;
883 }
884
885 /*
886 * This is an awful lot like cluster_rbuild...wish they could be combined.
887 * The last lbn argument is the current block on which I/O is being
888 * performed. Check to see that it doesn't fall in the middle of
889 * the current block (if last_bp == NULL).
890 *
891 * cluster_wbuild() normally does not guarantee anything. If bpp is
892 * non-NULL and cluster_wbuild() is able to incorporate it into the
893 * I/O it will set *bpp to NULL, otherwise it will leave it alone and
894 * the caller must dispose of *bpp.
895 */
896 static int
897 cluster_wbuild(struct vnode *vp, struct buf **bpp,
898 int blksize, off_t start_loffset, int bytes)
899 {
900 struct buf *bp, *tbp;
901 int i, j;
902 int totalwritten = 0;
903 int must_initiate;
904 int maxiosize = vmaxiosize(vp);
905
906 while (bytes > 0) {
907 /*
908 * If the buffer matches the passed locked & removed buffer
909 * we used the passed buffer (which might not be B_DELWRI).
910 *
911 * Otherwise locate the buffer and determine if it is
912 * compatible.
913 */
914 if (bpp && (*bpp)->b_loffset == start_loffset) {
915 tbp = *bpp;
916 *bpp = NULL;
917 bpp = NULL;
918 } else {
919 tbp = findblk(vp, start_loffset, FINDBLK_NBLOCK);
920 if (tbp == NULL ||
921 (tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) !=
922 B_DELWRI ||
923 (LIST_FIRST(&tbp->b_dep) && buf_checkwrite(tbp))) {
924 if (tbp)
925 BUF_UNLOCK(tbp);
926 start_loffset += blksize;
927 bytes -= blksize;
928 continue;
929 }
930 bremfree(tbp);
931 }
932 KKASSERT(tbp->b_cmd == BUF_CMD_DONE);
933
934 /*
935 * Extra memory in the buffer, punt on this buffer.
936 * XXX we could handle this in most cases, but we would
937 * have to push the extra memory down to after our max
938 * possible cluster size and then potentially pull it back
939 * up if the cluster was terminated prematurely--too much
940 * hassle.
941 */
942 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) ||
943 (tbp->b_bcount != tbp->b_bufsize) ||
944 (tbp->b_bcount != blksize) ||
945 (bytes == blksize) ||
946 ((bp = getpbuf_kva(&cluster_pbuf_freecnt)) == NULL)) {
947 totalwritten += tbp->b_bufsize;
948 bawrite(tbp);
949 start_loffset += blksize;
950 bytes -= blksize;
951 continue;
952 }
953
954 /*
955 * Set up the pbuf. Track our append point with b_bcount
956 * and b_bufsize. b_bufsize is not used by the device but
957 * our caller uses it to loop clusters and we use it to
958 * detect a premature EOF on the block device.
959 */
960 bp->b_bcount = 0;
961 bp->b_bufsize = 0;
962 bp->b_xio.xio_npages = 0;
963 bp->b_loffset = tbp->b_loffset;
964 bp->b_bio2.bio_offset = tbp->b_bio2.bio_offset;
965
966 /*
967 * We are synthesizing a buffer out of vm_page_t's, but
968 * if the block size is not page aligned then the starting
969 * address may not be either. Inherit the b_data offset
970 * from the original buffer.
971 */
972 bp->b_data = (char *)((vm_offset_t)bp->b_data |
973 ((vm_offset_t)tbp->b_data & PAGE_MASK));
974 bp->b_flags &= ~B_ERROR;
975 bp->b_flags |= B_CLUSTER | B_BNOCLIP |
976 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT));
977 bp->b_bio1.bio_caller_info1.cluster_head = NULL;
978 bp->b_bio1.bio_caller_info2.cluster_tail = NULL;
979
980 /*
981 * From this location in the file, scan forward to see
982 * if there are buffers with adjacent data that need to
983 * be written as well.
984 *
985 * IO *must* be initiated on index 0 at this point
986 * (particularly when called from cluster_awrite()).
987 */
988 for (i = 0; i < bytes; (i += blksize), (start_loffset += blksize)) {
989 if (i == 0) {
990 must_initiate = 1;
991 } else {
992 /*
993 * Not first buffer.
994 */
995 must_initiate = 0;
996 tbp = findblk(vp, start_loffset,
997 FINDBLK_NBLOCK);
998 /*
999 * Buffer not found or could not be locked
1000 * non-blocking.
1001 */
1002 if (tbp == NULL)
1003 break;
1004
1005 /*
1006 * If it IS in core, but has different
1007 * characteristics, then don't cluster
1008 * with it.
1009 */
1010 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK |
1011 B_INVAL | B_DELWRI | B_NEEDCOMMIT))
1012 != (B_DELWRI | B_CLUSTEROK |
1013 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) ||
1014 (tbp->b_flags & B_LOCKED)
1015 ) {
1016 BUF_UNLOCK(tbp);
1017 break;
1018 }
1019
1020 /*
1021 * Check that the combined cluster
1022 * would make sense with regard to pages
1023 * and would not be too large
1024 *
1025 * WARNING! buf_checkwrite() must be the last
1026 * check made. If it returns 0 then
1027 * we must initiate the I/O.
1028 */
1029 if ((tbp->b_bcount != blksize) ||
1030 ((bp->b_bio2.bio_offset + i) !=
1031 tbp->b_bio2.bio_offset) ||
1032 ((tbp->b_xio.xio_npages + bp->b_xio.xio_npages) >
1033 (maxiosize / PAGE_SIZE)) ||
1034 (LIST_FIRST(&tbp->b_dep) &&
1035 buf_checkwrite(tbp))
1036 ) {
1037 BUF_UNLOCK(tbp);
1038 break;
1039 }
1040 if (LIST_FIRST(&tbp->b_dep))
1041 must_initiate = 1;
1042 /*
1043 * Ok, it's passed all the tests,
1044 * so remove it from the free list
1045 * and mark it busy. We will use it.
1046 */
1047 bremfree(tbp);
1048 KKASSERT(tbp->b_cmd == BUF_CMD_DONE);
1049 }
1050
1051 /*
1052 * If the IO is via the VM then we do some
1053 * special VM hackery (yuck). Since the buffer's
1054 * block size may not be page-aligned it is possible
1055 * for a page to be shared between two buffers. We
1056 * have to get rid of the duplication when building
1057 * the cluster.
1058 */
1059 if (tbp->b_flags & B_VMIO) {
1060 vm_page_t m;
1061
1062 /*
1063 * Try to avoid deadlocks with the VM system.
1064 * However, we cannot abort the I/O if
1065 * must_initiate is non-zero.
1066 */
1067 if (must_initiate == 0) {
1068 for (j = 0;
1069 j < tbp->b_xio.xio_npages;
1070 ++j) {
1071 m = tbp->b_xio.xio_pages[j];
1072 if (m->flags & PG_BUSY) {
1073 bqrelse(tbp);
1074 goto finishcluster;
1075 }
1076 }
1077 }
1078
1079 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
1080 m = tbp->b_xio.xio_pages[j];
1081 vm_page_busy_wait(m, FALSE, "clurpg");
1082 vm_page_io_start(m);
1083 vm_page_wakeup(m);
1084 vm_object_pip_add(m->object, 1);
1085 if ((bp->b_xio.xio_npages == 0) ||
1086 (bp->b_xio.xio_pages[bp->b_xio.xio_npages - 1] != m)) {
1087 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m;
1088 bp->b_xio.xio_npages++;
1089 }
1090 }
1091 }
1092 bp->b_bcount += blksize;
1093 bp->b_bufsize += blksize;
1094
1095 bundirty(tbp);
1096 tbp->b_flags &= ~B_ERROR;
1097 tbp->b_cmd = BUF_CMD_WRITE;
1098 BUF_KERNPROC(tbp);
1099 cluster_append(&bp->b_bio1, tbp);
1100
1101 /*
1102 * check for latent dependencies to be handled
1103 */
1104 if (LIST_FIRST(&tbp->b_dep) != NULL)
1105 buf_start(tbp);
1106 }
1107 finishcluster:
1108 pmap_qenter(trunc_page((vm_offset_t)bp->b_data),
1109 (vm_page_t *)bp->b_xio.xio_pages,
1110 bp->b_xio.xio_npages);
1111 if (bp->b_bufsize > bp->b_kvasize) {
1112 panic("cluster_wbuild: b_bufsize(%d) "
1113 "> b_kvasize(%d)\n",
1114 bp->b_bufsize, bp->b_kvasize);
1115 }
1116 totalwritten += bp->b_bufsize;
1117 bp->b_dirtyoff = 0;
1118 bp->b_dirtyend = bp->b_bufsize;
1119 bp->b_bio1.bio_done = cluster_callback;
1120 bp->b_cmd = BUF_CMD_WRITE;
1121
1122 vfs_busy_pages(vp, bp);
1123 bsetrunningbufspace(bp, bp->b_bufsize);
1124 BUF_KERNPROC(bp);
1125 vn_strategy(vp, &bp->b_bio1);
1126
1127 bytes -= i;
1128 }
1129 return totalwritten;
1130 }
1131
1132 /*
1133 * Collect together all the buffers in a cluster, plus add one
1134 * additional buffer passed-in.
1135 *
1136 * Only pre-existing buffers whos block size matches blksize are collected.
1137 * (this is primarily because HAMMER1 uses varying block sizes and we don't
1138 * want to override its choices).
1139 */
1140 static struct cluster_save *
1141 cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int blksize)
1142 {
1143 struct cluster_save *buflist;
1144 struct buf *bp;
1145 off_t loffset;
1146 int i, len;
1147 int j;
1148 int k;
1149
1150 len = (int)(vp->v_lastw - vp->v_cstart + blksize) / blksize;
1151 buflist = kmalloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
1152 M_SEGMENT, M_WAITOK);
1153 buflist->bs_nchildren = 0;
1154 buflist->bs_children = (struct buf **) (buflist + 1);
1155 for (loffset = vp->v_cstart, i = 0, j = 0;
1156 i < len;
1157 (loffset += blksize), i++) {
1158 bp = getcacheblk(vp, loffset,
1159 last_bp->b_bcount, GETBLK_SZMATCH);
1160 buflist->bs_children[i] = bp;
1161 if (bp == NULL) {
1162 j = i + 1;
1163 } else if (bp->b_bio2.bio_offset == NOOFFSET) {
1164 VOP_BMAP(bp->b_vp, bp->b_loffset,
1165 &bp->b_bio2.bio_offset,
1166 NULL, NULL, BUF_CMD_WRITE);
1167 }
1168 }
1169
1170 /*
1171 * Get rid of gaps
1172 */
1173 for (k = 0; k < j; ++k) {
1174 if (buflist->bs_children[k]) {
1175 bqrelse(buflist->bs_children[k]);
1176 buflist->bs_children[k] = NULL;
1177 }
1178 }
1179 if (j != 0) {
1180 if (j != i) {
1181 bcopy(buflist->bs_children + j,
1182 buflist->bs_children + 0,
1183 sizeof(buflist->bs_children[0]) * (i - j));
1184 }
1185 i -= j;
1186 }
1187 buflist->bs_children[i] = bp = last_bp;
1188 if (bp->b_bio2.bio_offset == NOOFFSET) {
1189 VOP_BMAP(bp->b_vp, bp->b_loffset, &bp->b_bio2.bio_offset,
1190 NULL, NULL, BUF_CMD_WRITE);
1191 }
1192 buflist->bs_nchildren = i + 1;
1193 return (buflist);
1194 }
1195
1196 void
1197 cluster_append(struct bio *bio, struct buf *tbp)
1198 {
1199 tbp->b_cluster_next = NULL;
1200 if (bio->bio_caller_info1.cluster_head == NULL) {
1201 bio->bio_caller_info1.cluster_head = tbp;
1202 bio->bio_caller_info2.cluster_tail = tbp;
1203 } else {
1204 bio->bio_caller_info2.cluster_tail->b_cluster_next = tbp;
1205 bio->bio_caller_info2.cluster_tail = tbp;
1206 }
1207 }
1208
1209 static
1210 void
1211 cluster_setram (struct buf *bp)
1212 {
1213 bp->b_flags |= B_RAM;
1214 if (bp->b_xio.xio_npages)
1215 vm_page_flag_set(bp->b_xio.xio_pages[0], PG_RAM);
1216 }
DragonFly BSD