3 * The Regents of the University of California. All rights reserved.
4 * Modifications/enhancements:
5 * Copyright (c) 1995 John S. Dyson. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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
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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
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32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 $
40 #include "opt_debug_cluster.h"
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.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>
53 #include <vm/vm_object.h>
54 #include <vm/vm_page.h>
55 #include <sys/sysctl.h>
58 #include <vm/vm_page2.h>
60 #include <machine/limits.h>
62 #if defined(CLUSTERDEBUG)
63 #include <sys/sysctl.h>
64 static int rcluster= 0;
65 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, "");
68 static MALLOC_DEFINE(M_SEGMENT, "cluster_save", "cluster_save buffer");
70 static struct cluster_save *
71 cluster_collectbufs (struct vnode *vp, struct buf *last_bp,
74 cluster_rbuild (struct vnode *vp, off_t filesize, off_t loffset,
75 off_t doffset, int blksize, int run,
77 static void cluster_callback (struct bio *);
78 static void cluster_setram (struct buf *);
80 static int write_behind = 1;
81 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0,
82 "Cluster write-behind setting");
83 static int max_readahead = 2 * 1024 * 1024;
84 SYSCTL_INT(_vfs, OID_AUTO, max_readahead, CTLFLAG_RW, &max_readahead, 0,
85 "Limit in bytes for desired cluster read-ahead");
87 extern vm_page_t bogus_page;
89 extern int cluster_pbuf_freecnt;
92 * This replaces bread.
94 * filesize - read-ahead @ blksize will not cross this boundary
95 * loffset - loffset for returned *bpp
96 * blksize - blocksize for returned *bpp and read-ahead bps
97 * minreq - minimum (not a hard minimum) in bytes, typically reflects
98 * a higher level uio resid.
99 * maxreq - maximum (sequential heuristic) in bytes (highet typ ~2MB)
100 * bpp - return buffer (*bpp) for (loffset,blksize)
103 cluster_readx(struct vnode *vp, off_t filesize, off_t loffset,
104 int blksize, size_t minreq, size_t maxreq, struct buf **bpp)
106 struct buf *bp, *rbp, *reqbp;
117 * Calculate the desired read-ahead in blksize'd blocks (maxra).
118 * To do this we calculate maxreq.
120 * maxreq typically starts out as a sequential heuristic. If the
121 * high level uio/resid is bigger (minreq), we pop maxreq up to
122 * minreq. This represents the case where random I/O is being
123 * performed by the userland is issuing big read()'s.
125 * Then we limit maxreq to max_readahead to ensure it is a reasonable
128 * Finally we must ensure that (loffset + maxreq) does not cross the
129 * boundary (filesize) for the current blocksize. If we allowed it
130 * to cross we could end up with buffers past the boundary with the
131 * wrong block size (HAMMER large-data areas use mixed block sizes).
132 * minreq is also absolutely limited to filesize.
136 /* minreq not used beyond this point */
138 if (maxreq > max_readahead) {
139 maxreq = max_readahead;
140 if (maxreq > 16 * 1024 * 1024)
141 maxreq = 16 * 1024 * 1024;
143 if (maxreq < blksize)
145 if (loffset + maxreq > filesize) {
146 if (loffset > filesize)
149 maxreq = filesize - loffset;
152 maxra = (int)(maxreq / blksize);
155 * Get the requested block.
160 *bpp = reqbp = bp = getblk(vp, loffset, blksize, 0, 0);
161 origoffset = loffset;
164 * Calculate the maximum cluster size for a single I/O, used
165 * by cluster_rbuild().
167 maxrbuild = vmaxiosize(vp) / blksize;
170 * if it is in the cache, then check to see if the reads have been
171 * sequential. If they have, then try some read-ahead, otherwise
172 * back-off on prospective read-aheads.
174 if (bp->b_flags & B_CACHE) {
176 * Not sequential, do not do any read-ahead
182 * No read-ahead mark, do not do any read-ahead
185 if ((bp->b_flags & B_RAM) == 0)
189 * We hit a read-ahead-mark, figure out how much read-ahead
190 * to do (maxra) and where to start (loffset).
192 * Shortcut the scan. Typically the way this works is that
193 * we've built up all the blocks inbetween except for the
194 * last in previous iterations, so if the second-to-last
195 * block is present we just skip ahead to it.
197 * This algorithm has O(1) cpu in the steady state no
198 * matter how large maxra is.
200 bp->b_flags &= ~B_RAM;
202 if (findblk(vp, loffset + (maxra - 2) * blksize, FINDBLK_TEST))
207 if (findblk(vp, loffset + i * blksize,
208 FINDBLK_TEST) == NULL) {
215 * We got everything or everything is in the cache, no
221 loffset += i * blksize;
224 __debugvar off_t firstread = bp->b_loffset;
228 * Set-up synchronous read for bp.
230 bp->b_cmd = BUF_CMD_READ;
231 bp->b_bio1.bio_done = biodone_sync;
232 bp->b_bio1.bio_flags |= BIO_SYNC;
234 KASSERT(firstread != NOOFFSET,
235 ("cluster_read: no buffer offset"));
238 * nblks is our cluster_rbuild request size, limited
239 * primarily by the device.
241 if ((nblks = maxra) > maxrbuild)
247 error = VOP_BMAP(vp, loffset, &doffset,
248 &burstbytes, NULL, BUF_CMD_READ);
250 goto single_block_read;
251 if (nblks > burstbytes / blksize)
252 nblks = burstbytes / blksize;
253 if (doffset == NOOFFSET)
254 goto single_block_read;
256 goto single_block_read;
258 bp = cluster_rbuild(vp, filesize, loffset,
259 doffset, blksize, nblks, bp);
260 loffset += bp->b_bufsize;
261 maxra -= bp->b_bufsize / blksize;
265 * If it isn't in the cache, then get a chunk from
266 * disk if sequential, otherwise just get the block.
275 * If B_CACHE was not set issue bp. bp will either be an
276 * asynchronous cluster buf or a synchronous single-buf.
277 * If it is a single buf it will be the same as reqbp.
279 * NOTE: Once an async cluster buf is issued bp becomes invalid.
282 #if defined(CLUSTERDEBUG)
284 kprintf("S(%012jx,%d,%d)\n",
285 (intmax_t)bp->b_loffset, bp->b_bcount, maxra);
287 if ((bp->b_flags & B_CLUSTER) == 0)
288 vfs_busy_pages(vp, bp);
289 bp->b_flags &= ~(B_ERROR|B_INVAL);
290 vn_strategy(vp, &bp->b_bio1);
296 * If we have been doing sequential I/O, then do some read-ahead.
297 * The code above us should have positioned us at the next likely
300 * Only mess with buffers which we can immediately lock. HAMMER
301 * will do device-readahead irrespective of what the blocks
304 while (error == 0 && maxra > 0) {
309 rbp = getblk(vp, loffset, blksize,
310 GETBLK_SZMATCH|GETBLK_NOWAIT, 0);
313 if ((rbp->b_flags & B_CACHE)) {
319 * An error from the read-ahead bmap has nothing to do
320 * with the caller's original request.
322 tmp_error = VOP_BMAP(vp, loffset, &doffset,
323 &burstbytes, NULL, BUF_CMD_READ);
324 if (tmp_error || doffset == NOOFFSET) {
325 rbp->b_flags |= B_INVAL;
330 if ((nblks = maxra) > maxrbuild)
332 if (nblks > burstbytes / blksize)
333 nblks = burstbytes / blksize;
338 rbp->b_cmd = BUF_CMD_READ;
339 /*rbp->b_flags |= B_AGE*/;
343 rbp = cluster_rbuild(vp, filesize, loffset,
347 rbp->b_bio2.bio_offset = doffset;
350 #if defined(CLUSTERDEBUG)
353 kprintf("A+(%012jx,%d,%jd) "
354 "doff=%012jx minr=%zd ra=%d\n",
355 (intmax_t)loffset, rbp->b_bcount,
356 (intmax_t)(loffset - origoffset),
357 (intmax_t)doffset, minreq, maxra);
359 kprintf("A-(%012jx,%d,%jd) "
360 "doff=%012jx minr=%zd ra=%d\n",
361 (intmax_t)rbp->b_loffset, rbp->b_bcount,
362 (intmax_t)(loffset - origoffset),
363 (intmax_t)doffset, minreq, maxra);
367 rbp->b_flags &= ~(B_ERROR|B_INVAL);
369 if ((rbp->b_flags & B_CLUSTER) == 0)
370 vfs_busy_pages(vp, rbp);
372 loffset += rbp->b_bufsize;
373 maxra -= rbp->b_bufsize / blksize;
374 vn_strategy(vp, &rbp->b_bio1);
375 /* rbp invalid now */
379 * Wait for our original buffer to complete its I/O. reqbp will
380 * be NULL if the original buffer was B_CACHE. We are returning
381 * (*bpp) which is the same as reqbp when reqbp != NULL.
385 KKASSERT(reqbp->b_bio1.bio_flags & BIO_SYNC);
386 error = biowait(&reqbp->b_bio1, "clurd");
392 * If blocks are contiguous on disk, use this to provide clustered
393 * read ahead. We will read as many blocks as possible sequentially
394 * and then parcel them up into logical blocks in the buffer hash table.
396 * This function either returns a cluster buf or it returns fbp. fbp is
397 * already expected to be set up as a synchronous or asynchronous request.
399 * If a cluster buf is returned it will always be async.
402 cluster_rbuild(struct vnode *vp, off_t filesize, off_t loffset, off_t doffset,
403 int blksize, int run, struct buf *fbp)
405 struct buf *bp, *tbp;
408 int maxiosize = vmaxiosize(vp);
413 while (loffset + run * blksize > filesize) {
418 tbp->b_bio2.bio_offset = doffset;
419 if((tbp->b_flags & B_MALLOC) ||
420 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1)) {
424 bp = trypbuf_kva(&cluster_pbuf_freecnt);
430 * We are synthesizing a buffer out of vm_page_t's, but
431 * if the block size is not page aligned then the starting
432 * address may not be either. Inherit the b_data offset
433 * from the original buffer.
435 bp->b_data = (char *)((vm_offset_t)bp->b_data |
436 ((vm_offset_t)tbp->b_data & PAGE_MASK));
437 bp->b_flags |= B_CLUSTER | B_VMIO;
438 bp->b_cmd = BUF_CMD_READ;
439 bp->b_bio1.bio_done = cluster_callback; /* default to async */
440 bp->b_bio1.bio_caller_info1.cluster_head = NULL;
441 bp->b_bio1.bio_caller_info2.cluster_tail = NULL;
442 bp->b_loffset = loffset;
443 bp->b_bio2.bio_offset = doffset;
444 KASSERT(bp->b_loffset != NOOFFSET,
445 ("cluster_rbuild: no buffer offset"));
449 bp->b_xio.xio_npages = 0;
451 for (boffset = doffset, i = 0; i < run; ++i, boffset += blksize) {
453 if ((bp->b_xio.xio_npages * PAGE_SIZE) +
454 round_page(blksize) > maxiosize) {
459 * Shortcut some checks and try to avoid buffers that
460 * would block in the lock. The same checks have to
461 * be made again after we officially get the buffer.
463 tbp = getblk(vp, loffset + i * blksize, blksize,
464 GETBLK_SZMATCH|GETBLK_NOWAIT, 0);
467 for (j = 0; j < tbp->b_xio.xio_npages; j++) {
468 if (tbp->b_xio.xio_pages[j]->valid)
471 if (j != tbp->b_xio.xio_npages) {
477 * Stop scanning if the buffer is fuly valid
478 * (marked B_CACHE), or locked (may be doing a
479 * background write), or if the buffer is not
480 * VMIO backed. The clustering code can only deal
481 * with VMIO-backed buffers.
483 if ((tbp->b_flags & (B_CACHE|B_LOCKED)) ||
484 (tbp->b_flags & B_VMIO) == 0 ||
485 (LIST_FIRST(&tbp->b_dep) != NULL &&
493 * The buffer must be completely invalid in order to
494 * take part in the cluster. If it is partially valid
497 for (j = 0;j < tbp->b_xio.xio_npages; j++) {
498 if (tbp->b_xio.xio_pages[j]->valid)
501 if (j != tbp->b_xio.xio_npages) {
507 * Set a read-ahead mark as appropriate
509 if (i == 1 || i == (run - 1))
513 * Depress the priority of buffers not explicitly
516 /* tbp->b_flags |= B_AGE; */
519 * Set the block number if it isn't set, otherwise
520 * if it is make sure it matches the block number we
523 if (tbp->b_bio2.bio_offset == NOOFFSET) {
524 tbp->b_bio2.bio_offset = boffset;
525 } else if (tbp->b_bio2.bio_offset != boffset) {
532 * The passed-in tbp (i == 0) will already be set up for
533 * async or sync operation. All other tbp's acquire in
534 * our loop are set up for async operation.
536 tbp->b_cmd = BUF_CMD_READ;
538 cluster_append(&bp->b_bio1, tbp);
539 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
542 m = tbp->b_xio.xio_pages[j];
543 vm_page_busy_wait(m, FALSE, "clurpg");
546 vm_object_pip_add(m->object, 1);
547 if ((bp->b_xio.xio_npages == 0) ||
548 (bp->b_xio.xio_pages[bp->b_xio.xio_npages-1] != m)) {
549 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m;
550 bp->b_xio.xio_npages++;
552 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL)
553 tbp->b_xio.xio_pages[j] = bogus_page;
556 * XXX shouldn't this be += size for both, like in
559 * Don't inherit tbp->b_bufsize as it may be larger due to
560 * a non-page-aligned size. Instead just aggregate using
563 if (tbp->b_bcount != blksize)
564 kprintf("warning: tbp->b_bcount wrong %d vs %d\n", tbp->b_bcount, blksize);
565 if (tbp->b_bufsize != blksize)
566 kprintf("warning: tbp->b_bufsize wrong %d vs %d\n", tbp->b_bufsize, blksize);
567 bp->b_bcount += blksize;
568 bp->b_bufsize += blksize;
572 * Fully valid pages in the cluster are already good and do not need
573 * to be re-read from disk. Replace the page with bogus_page
575 for (j = 0; j < bp->b_xio.xio_npages; j++) {
576 if ((bp->b_xio.xio_pages[j]->valid & VM_PAGE_BITS_ALL) ==
578 bp->b_xio.xio_pages[j] = bogus_page;
581 if (bp->b_bufsize > bp->b_kvasize) {
582 panic("cluster_rbuild: b_bufsize(%d) > b_kvasize(%d)",
583 bp->b_bufsize, bp->b_kvasize);
585 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
586 (vm_page_t *)bp->b_xio.xio_pages, bp->b_xio.xio_npages);
592 * Cleanup after a clustered read or write.
593 * This is complicated by the fact that any of the buffers might have
594 * extra memory (if there were no empty buffer headers at allocbuf time)
595 * that we will need to shift around.
597 * The returned bio is &bp->b_bio1
600 cluster_callback(struct bio *bio)
602 struct buf *bp = bio->bio_buf;
607 * Must propogate errors to all the components. A short read (EOF)
608 * is a critical error.
610 if (bp->b_flags & B_ERROR) {
612 } else if (bp->b_bcount != bp->b_bufsize) {
613 panic("cluster_callback: unexpected EOF on cluster %p!", bio);
616 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_xio.xio_npages);
618 * Move memory from the large cluster buffer into the component
619 * buffers and mark IO as done on these. Since the memory map
620 * is the same, no actual copying is required.
622 while ((tbp = bio->bio_caller_info1.cluster_head) != NULL) {
623 bio->bio_caller_info1.cluster_head = tbp->b_cluster_next;
625 tbp->b_flags |= B_ERROR | B_IODEBUG;
626 tbp->b_error = error;
628 tbp->b_dirtyoff = tbp->b_dirtyend = 0;
629 tbp->b_flags &= ~(B_ERROR|B_INVAL);
630 tbp->b_flags |= B_IODEBUG;
632 * XXX the bdwrite()/bqrelse() issued during
633 * cluster building clears B_RELBUF (see bqrelse()
634 * comment). If direct I/O was specified, we have
635 * to restore it here to allow the buffer and VM
638 if (tbp->b_flags & B_DIRECT)
639 tbp->b_flags |= B_RELBUF;
641 biodone(&tbp->b_bio1);
643 relpbuf(bp, &cluster_pbuf_freecnt);
649 * Implement modified write build for cluster.
651 * write_behind = 0 write behind disabled
652 * write_behind = 1 write behind normal (default)
653 * write_behind = 2 write behind backed-off
657 cluster_wbuild_wb(struct vnode *vp, int blksize, off_t start_loffset, int len)
661 switch(write_behind) {
663 if (start_loffset < len)
665 start_loffset -= len;
668 r = cluster_wbuild(vp, blksize, start_loffset, len);
678 * Do clustered write for FFS.
681 * 1. Write is not sequential (write asynchronously)
682 * Write is sequential:
683 * 2. beginning of cluster - begin cluster
684 * 3. middle of a cluster - add to cluster
685 * 4. end of a cluster - asynchronously write cluster
688 cluster_write(struct buf *bp, off_t filesize, int blksize, int seqcount)
692 int maxclen, cursize;
696 if (vp->v_type == VREG)
697 async = vp->v_mount->mnt_flag & MNT_ASYNC;
700 loffset = bp->b_loffset;
701 KASSERT(bp->b_loffset != NOOFFSET,
702 ("cluster_write: no buffer offset"));
704 /* Initialize vnode to beginning of file. */
706 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
708 if (vp->v_clen == 0 || loffset != vp->v_lastw + blksize ||
709 bp->b_bio2.bio_offset == NOOFFSET ||
710 (bp->b_bio2.bio_offset != vp->v_lasta + blksize)) {
711 maxclen = vmaxiosize(vp);
712 if (vp->v_clen != 0) {
714 * Next block is not sequential.
716 * If we are not writing at end of file, the process
717 * seeked to another point in the file since its last
718 * write, or we have reached our maximum cluster size,
719 * then push the previous cluster. Otherwise try
720 * reallocating to make it sequential.
722 * Change to algorithm: only push previous cluster if
723 * it was sequential from the point of view of the
724 * seqcount heuristic, otherwise leave the buffer
725 * intact so we can potentially optimize the I/O
726 * later on in the buf_daemon or update daemon
729 cursize = vp->v_lastw - vp->v_cstart + blksize;
730 if (bp->b_loffset + blksize != filesize ||
731 loffset != vp->v_lastw + blksize || vp->v_clen <= cursize) {
732 if (!async && seqcount > 0) {
733 cluster_wbuild_wb(vp, blksize,
734 vp->v_cstart, cursize);
737 struct buf **bpp, **endbp;
738 struct cluster_save *buflist;
740 buflist = cluster_collectbufs(vp, bp, blksize);
741 endbp = &buflist->bs_children
742 [buflist->bs_nchildren - 1];
743 if (VOP_REALLOCBLKS(vp, buflist)) {
745 * Failed, push the previous cluster
746 * if *really* writing sequentially
747 * in the logical file (seqcount > 1),
748 * otherwise delay it in the hopes that
749 * the low level disk driver can
750 * optimize the write ordering.
752 for (bpp = buflist->bs_children;
755 kfree(buflist, M_SEGMENT);
757 cluster_wbuild_wb(vp,
758 blksize, vp->v_cstart,
763 * Succeeded, keep building cluster.
765 for (bpp = buflist->bs_children;
768 kfree(buflist, M_SEGMENT);
769 vp->v_lastw = loffset;
770 vp->v_lasta = bp->b_bio2.bio_offset;
776 * Consider beginning a cluster. If at end of file, make
777 * cluster as large as possible, otherwise find size of
780 if ((vp->v_type == VREG) &&
781 bp->b_loffset + blksize != filesize &&
782 (bp->b_bio2.bio_offset == NOOFFSET) &&
783 (VOP_BMAP(vp, loffset, &bp->b_bio2.bio_offset, &maxclen, NULL, BUF_CMD_WRITE) ||
784 bp->b_bio2.bio_offset == NOOFFSET)) {
787 vp->v_lasta = bp->b_bio2.bio_offset;
788 vp->v_cstart = loffset + blksize;
789 vp->v_lastw = loffset;
792 if (maxclen > blksize)
793 vp->v_clen = maxclen - blksize;
796 if (!async && vp->v_clen == 0) { /* I/O not contiguous */
797 vp->v_cstart = loffset + blksize;
799 } else { /* Wait for rest of cluster */
800 vp->v_cstart = loffset;
803 } else if (loffset == vp->v_cstart + vp->v_clen) {
805 * At end of cluster, write it out if seqcount tells us we
806 * are operating sequentially, otherwise let the buf or
807 * update daemon handle it.
811 cluster_wbuild_wb(vp, blksize, vp->v_cstart,
812 vp->v_clen + blksize);
814 vp->v_cstart = loffset + blksize;
815 } else if (vm_page_count_severe()) {
817 * We are low on memory, get it going NOW
822 * In the middle of a cluster, so just delay the I/O for now.
826 vp->v_lastw = loffset;
827 vp->v_lasta = bp->b_bio2.bio_offset;
832 * This is an awful lot like cluster_rbuild...wish they could be combined.
833 * The last lbn argument is the current block on which I/O is being
834 * performed. Check to see that it doesn't fall in the middle of
835 * the current block (if last_bp == NULL).
838 cluster_wbuild(struct vnode *vp, int blksize, off_t start_loffset, int bytes)
840 struct buf *bp, *tbp;
842 int totalwritten = 0;
843 int maxiosize = vmaxiosize(vp);
847 * If the buffer is not delayed-write (i.e. dirty), or it
848 * is delayed-write but either locked or inval, it cannot
849 * partake in the clustered write.
851 tbp = findblk(vp, start_loffset, FINDBLK_NBLOCK);
853 (tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI ||
854 (LIST_FIRST(&tbp->b_dep) && buf_checkwrite(tbp))) {
857 start_loffset += blksize;
862 KKASSERT(tbp->b_cmd == BUF_CMD_DONE);
865 * Extra memory in the buffer, punt on this buffer.
866 * XXX we could handle this in most cases, but we would
867 * have to push the extra memory down to after our max
868 * possible cluster size and then potentially pull it back
869 * up if the cluster was terminated prematurely--too much
872 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) ||
873 (tbp->b_bcount != tbp->b_bufsize) ||
874 (tbp->b_bcount != blksize) ||
875 (bytes == blksize) ||
876 ((bp = getpbuf_kva(&cluster_pbuf_freecnt)) == NULL)) {
877 totalwritten += tbp->b_bufsize;
879 start_loffset += blksize;
885 * Set up the pbuf. Track our append point with b_bcount
886 * and b_bufsize. b_bufsize is not used by the device but
887 * our caller uses it to loop clusters and we use it to
888 * detect a premature EOF on the block device.
892 bp->b_xio.xio_npages = 0;
893 bp->b_loffset = tbp->b_loffset;
894 bp->b_bio2.bio_offset = tbp->b_bio2.bio_offset;
897 * We are synthesizing a buffer out of vm_page_t's, but
898 * if the block size is not page aligned then the starting
899 * address may not be either. Inherit the b_data offset
900 * from the original buffer.
902 bp->b_data = (char *)((vm_offset_t)bp->b_data |
903 ((vm_offset_t)tbp->b_data & PAGE_MASK));
904 bp->b_flags &= ~B_ERROR;
905 bp->b_flags |= B_CLUSTER | B_BNOCLIP |
906 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT));
907 bp->b_bio1.bio_caller_info1.cluster_head = NULL;
908 bp->b_bio1.bio_caller_info2.cluster_tail = NULL;
911 * From this location in the file, scan forward to see
912 * if there are buffers with adjacent data that need to
913 * be written as well.
915 for (i = 0; i < bytes; (i += blksize), (start_loffset += blksize)) {
916 if (i != 0) { /* If not the first buffer */
917 tbp = findblk(vp, start_loffset,
920 * Buffer not found or could not be locked
927 * If it IS in core, but has different
928 * characteristics, then don't cluster
931 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK |
932 B_INVAL | B_DELWRI | B_NEEDCOMMIT))
933 != (B_DELWRI | B_CLUSTEROK |
934 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) ||
935 (tbp->b_flags & B_LOCKED) ||
936 (LIST_FIRST(&tbp->b_dep) &&
944 * Check that the combined cluster
945 * would make sense with regard to pages
946 * and would not be too large
948 if ((tbp->b_bcount != blksize) ||
949 ((bp->b_bio2.bio_offset + i) !=
950 tbp->b_bio2.bio_offset) ||
951 ((tbp->b_xio.xio_npages + bp->b_xio.xio_npages) >
952 (maxiosize / PAGE_SIZE))) {
957 * Ok, it's passed all the tests,
958 * so remove it from the free list
959 * and mark it busy. We will use it.
962 KKASSERT(tbp->b_cmd == BUF_CMD_DONE);
963 } /* end of code for non-first buffers only */
966 * If the IO is via the VM then we do some
967 * special VM hackery (yuck). Since the buffer's
968 * block size may not be page-aligned it is possible
969 * for a page to be shared between two buffers. We
970 * have to get rid of the duplication when building
973 if (tbp->b_flags & B_VMIO) {
976 if (i != 0) { /* if not first buffer */
977 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
978 m = tbp->b_xio.xio_pages[j];
979 if (m->flags & PG_BUSY) {
986 for (j = 0; j < tbp->b_xio.xio_npages; ++j) {
987 m = tbp->b_xio.xio_pages[j];
988 vm_page_busy_wait(m, FALSE, "clurpg");
991 vm_object_pip_add(m->object, 1);
992 if ((bp->b_xio.xio_npages == 0) ||
993 (bp->b_xio.xio_pages[bp->b_xio.xio_npages - 1] != m)) {
994 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m;
995 bp->b_xio.xio_npages++;
999 bp->b_bcount += blksize;
1000 bp->b_bufsize += blksize;
1003 tbp->b_flags &= ~B_ERROR;
1004 tbp->b_cmd = BUF_CMD_WRITE;
1006 cluster_append(&bp->b_bio1, tbp);
1009 * check for latent dependencies to be handled
1011 if (LIST_FIRST(&tbp->b_dep) != NULL)
1015 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
1016 (vm_page_t *) bp->b_xio.xio_pages, bp->b_xio.xio_npages);
1017 if (bp->b_bufsize > bp->b_kvasize) {
1019 "cluster_wbuild: b_bufsize(%d) > b_kvasize(%d)\n",
1020 bp->b_bufsize, bp->b_kvasize);
1022 totalwritten += bp->b_bufsize;
1024 bp->b_dirtyend = bp->b_bufsize;
1025 bp->b_bio1.bio_done = cluster_callback;
1026 bp->b_cmd = BUF_CMD_WRITE;
1028 vfs_busy_pages(vp, bp);
1029 bsetrunningbufspace(bp, bp->b_bufsize);
1031 vn_strategy(vp, &bp->b_bio1);
1035 return totalwritten;
1039 * Collect together all the buffers in a cluster.
1040 * Plus add one additional buffer.
1042 static struct cluster_save *
1043 cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int blksize)
1045 struct cluster_save *buflist;
1050 len = (int)(vp->v_lastw - vp->v_cstart + blksize) / blksize;
1051 buflist = kmalloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
1052 M_SEGMENT, M_WAITOK);
1053 buflist->bs_nchildren = 0;
1054 buflist->bs_children = (struct buf **) (buflist + 1);
1055 for (loffset = vp->v_cstart, i = 0; i < len; (loffset += blksize), i++) {
1056 (void) bread(vp, loffset, last_bp->b_bcount, &bp);
1057 buflist->bs_children[i] = bp;
1058 if (bp->b_bio2.bio_offset == NOOFFSET) {
1059 VOP_BMAP(bp->b_vp, bp->b_loffset,
1060 &bp->b_bio2.bio_offset,
1061 NULL, NULL, BUF_CMD_WRITE);
1064 buflist->bs_children[i] = bp = last_bp;
1065 if (bp->b_bio2.bio_offset == NOOFFSET) {
1066 VOP_BMAP(bp->b_vp, bp->b_loffset, &bp->b_bio2.bio_offset,
1067 NULL, NULL, BUF_CMD_WRITE);
1069 buflist->bs_nchildren = i + 1;
1074 cluster_append(struct bio *bio, struct buf *tbp)
1076 tbp->b_cluster_next = NULL;
1077 if (bio->bio_caller_info1.cluster_head == NULL) {
1078 bio->bio_caller_info1.cluster_head = tbp;
1079 bio->bio_caller_info2.cluster_tail = tbp;
1081 bio->bio_caller_info2.cluster_tail->b_cluster_next = tbp;
1082 bio->bio_caller_info2.cluster_tail = tbp;
1088 cluster_setram (struct buf *bp)
1090 bp->b_flags |= B_RAM;
1091 if (bp->b_xio.xio_npages)
1092 vm_page_flag_set(bp->b_xio.xio_pages[0], PG_RAM);