2 * SPDX-License-Identifier: BSD-3-Clause
5 * The Regents of the University of California. All rights reserved.
6 * Modifications/enhancements:
7 * Copyright (c) 1995 John S. Dyson. All rights reserved.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
40 #include <sys/vnode.h>
41 #include <sys/malloc.h>
42 #include <sys/mount.h>
43 #include <sys/racct.h>
44 #include <sys/resourcevar.h>
45 #include <sys/rwlock.h>
46 #include <sys/vmmeter.h>
48 #include <vm/vm_object.h>
49 #include <vm/vm_page.h>
50 #include <sys/sysctl.h>
52 static MALLOC_DEFINE(M_SEGMENT, "cl_savebuf", "cluster_save buffer");
53 static uma_zone_t cluster_pbuf_zone;
55 static void cluster_init(void *);
56 static struct cluster_save *cluster_collectbufs(struct vnode *vp,
57 struct vn_clusterw *vnc, struct buf *last_bp, int gbflags);
58 static struct buf *cluster_rbuild(struct vnode *vp, u_quad_t filesize,
59 daddr_t lbn, daddr_t blkno, long size, int run, int gbflags,
61 static void cluster_callback(struct buf *);
63 static int write_behind = 1;
64 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0,
65 "Cluster write-behind; 0: disable, 1: enable, 2: backed off");
67 static int read_max = 64;
68 SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0,
69 "Cluster read-ahead max block count");
71 static int read_min = 1;
72 SYSCTL_INT(_vfs, OID_AUTO, read_min, CTLFLAG_RW, &read_min, 0,
73 "Cluster read min block count");
75 SYSINIT(cluster, SI_SUB_CPU, SI_ORDER_ANY, cluster_init, NULL);
78 cluster_init(void *dummy)
81 cluster_pbuf_zone = pbuf_zsecond_create("clpbuf", nswbuf / 2);
85 * Read data to a buf, including read-ahead if we find this to be beneficial.
86 * cluster_read replaces bread.
89 cluster_read(struct vnode *vp, u_quad_t filesize, daddr_t lblkno, long size,
90 struct ucred *cred, long totread, int seqcount, int gbflags,
93 struct buf *bp, *rbp, *reqbp;
96 daddr_t blkno, origblkno;
104 if (!unmapped_buf_allowed)
105 gbflags &= ~GB_UNMAPPED;
108 * Try to limit the amount of read-ahead by a few
109 * ad-hoc parameters. This needs work!!!
111 racluster = vp->v_mount->mnt_iosize_max / size;
113 maxra = min(read_max, maxra);
114 maxra = min(nbuf/8, maxra);
115 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize)
116 maxra = (filesize / size) - lblkno;
119 * get the requested block
121 error = getblkx(vp, lblkno, lblkno, size, 0, 0, gbflags, &bp);
126 gbflags &= ~GB_NOSPARSE;
131 * if it is in the cache, then check to see if the reads have been
132 * sequential. If they have, then try some read-ahead, otherwise
133 * back-off on prospective read-aheads.
135 if (bp->b_flags & B_CACHE) {
138 } else if ((bp->b_flags & B_RAM) == 0) {
141 bp->b_flags &= ~B_RAM;
143 for (i = 1; i < maxra; i++) {
145 * Stop if the buffer does not exist or it
146 * is invalid (about to go away?)
148 rbp = gbincore(&vp->v_bufobj, lblkno+i);
149 if (rbp == NULL || (rbp->b_flags & B_INVAL))
153 * Set another read-ahead mark so we know
154 * to check again. (If we can lock the
155 * buffer without waiting)
157 if ((((i % racluster) == (racluster - 1)) ||
159 && (0 == BUF_LOCK(rbp,
160 LK_EXCLUSIVE | LK_NOWAIT, NULL))) {
161 rbp->b_flags |= B_RAM;
173 * If it isn't in the cache, then get a chunk from
174 * disk if sequential, otherwise just get the block.
177 off_t firstread = bp->b_offset;
181 KASSERT(bp->b_offset != NOOFFSET,
182 ("cluster_read: no buffer offset"));
187 * Adjust totread if needed
189 minread = read_min * size;
190 if (minread > totread)
194 * Compute the total number of blocks that we should read
197 if (firstread + totread > filesize)
198 totread = filesize - firstread;
199 nblks = howmany(totread, size);
200 if (nblks > racluster)
204 * Now compute the number of contiguous blocks.
207 error = VOP_BMAP(vp, lblkno, NULL,
208 &blkno, &ncontig, NULL);
210 * If this failed to map just do the original block.
212 if (error || blkno == -1)
217 * If we have contiguous data available do a cluster
218 * otherwise just read the requested block.
221 /* Account for our first block. */
222 ncontig = min(ncontig + 1, nblks);
225 bp = cluster_rbuild(vp, filesize, lblkno,
226 blkno, size, nblks, gbflags, bp);
227 lblkno += (bp->b_bufsize / size);
229 bp->b_flags |= B_RAM;
230 bp->b_iocmd = BIO_READ;
236 * handle the synchronous read so that it is available ASAP.
239 if ((bp->b_flags & B_CLUSTER) == 0) {
240 vfs_busy_pages(bp, 0);
242 bp->b_flags &= ~B_INVAL;
243 bp->b_ioflags &= ~BIO_ERROR;
244 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL)
246 bp->b_iooffset = dbtob(bp->b_blkno);
250 PROC_LOCK(td->td_proc);
251 racct_add_buf(td->td_proc, bp, 0);
252 PROC_UNLOCK(td->td_proc);
255 td->td_ru.ru_inblock++;
259 * If we have been doing sequential I/O, then do some read-ahead.
261 while (lblkno < (origblkno + maxra)) {
262 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL);
270 * We could throttle ncontig here by maxra but we might as
271 * well read the data if it is contiguous. We're throttled
272 * by racluster anyway.
275 ncontig = min(ncontig + 1, racluster);
276 rbp = cluster_rbuild(vp, filesize, lblkno, blkno,
277 size, ncontig, gbflags, NULL);
278 lblkno += (rbp->b_bufsize / size);
279 if (rbp->b_flags & B_DELWRI) {
284 rbp = getblk(vp, lblkno, size, 0, 0, gbflags);
286 if (rbp->b_flags & B_DELWRI) {
290 rbp->b_flags |= B_ASYNC | B_RAM;
291 rbp->b_iocmd = BIO_READ;
292 rbp->b_blkno = blkno;
294 if (rbp->b_flags & B_CACHE) {
295 rbp->b_flags &= ~B_ASYNC;
299 if ((rbp->b_flags & B_CLUSTER) == 0) {
300 vfs_busy_pages(rbp, 0);
302 rbp->b_flags &= ~B_INVAL;
303 rbp->b_ioflags &= ~BIO_ERROR;
304 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL)
306 rbp->b_iooffset = dbtob(rbp->b_blkno);
310 PROC_LOCK(td->td_proc);
311 racct_add_buf(td->td_proc, rbp, 0);
312 PROC_UNLOCK(td->td_proc);
315 td->td_ru.ru_inblock++;
320 * Like bread, always brelse() the buffer when
321 * returning an error.
323 error = bufwait(reqbp);
333 * If blocks are contiguous on disk, use this to provide clustered
334 * read ahead. We will read as many blocks as possible sequentially
335 * and then parcel them up into logical blocks in the buffer hash table.
338 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn,
339 daddr_t blkno, long size, int run, int gbflags, struct buf *fbp)
341 struct buf *bp, *tbp;
345 int i, inc, j, k, toff;
347 KASSERT(size == vp->v_mount->mnt_stat.f_iosize,
348 ("cluster_rbuild: size %ld != f_iosize %jd\n",
349 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize));
354 while ((u_quad_t) size * (lbn + run) > filesize) {
360 tbp->b_iocmd = BIO_READ;
362 tbp = getblk(vp, lbn, size, 0, 0, gbflags);
363 if (tbp->b_flags & B_CACHE)
365 tbp->b_flags |= B_ASYNC | B_RAM;
366 tbp->b_iocmd = BIO_READ;
368 tbp->b_blkno = blkno;
369 if ( (tbp->b_flags & B_MALLOC) ||
370 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) )
373 bp = uma_zalloc(cluster_pbuf_zone, M_NOWAIT);
376 MPASS((bp->b_flags & B_MAXPHYS) != 0);
379 * We are synthesizing a buffer out of vm_page_t's, but
380 * if the block size is not page aligned then the starting
381 * address may not be either. Inherit the b_data offset
382 * from the original buffer.
384 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO;
385 if ((gbflags & GB_UNMAPPED) != 0) {
386 bp->b_data = unmapped_buf;
388 bp->b_data = (char *)((vm_offset_t)bp->b_data |
389 ((vm_offset_t)tbp->b_data & PAGE_MASK));
391 bp->b_iocmd = BIO_READ;
392 bp->b_iodone = cluster_callback;
395 bp->b_offset = tbp->b_offset;
396 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset"));
399 TAILQ_INIT(&bp->b_cluster.cluster_head);
406 for (bn = blkno, i = 0; i < run; ++i, bn += inc) {
408 vm_object_pip_add(tbp->b_bufobj->bo_object,
410 vfs_busy_pages_acquire(tbp);
412 if ((bp->b_npages * PAGE_SIZE) +
413 round_page(size) > vp->v_mount->mnt_iosize_max) {
417 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT |
418 (gbflags & GB_UNMAPPED));
420 /* Don't wait around for locked bufs. */
425 * Stop scanning if the buffer is fully valid
426 * (marked B_CACHE), or locked (may be doing a
427 * background write), or if the buffer is not
428 * VMIO backed. The clustering code can only deal
429 * with VMIO-backed buffers. The bo lock is not
430 * required for the BKGRDINPROG check since it
431 * can not be set without the buf lock.
433 if ((tbp->b_vflags & BV_BKGRDINPROG) ||
434 (tbp->b_flags & B_CACHE) ||
435 (tbp->b_flags & B_VMIO) == 0) {
441 * The buffer must be completely invalid in order to
442 * take part in the cluster. If it is partially valid
447 for (j = 0; tsize > 0; j++) {
448 toff = off & PAGE_MASK;
450 if (toff + tinc > PAGE_SIZE)
451 tinc = PAGE_SIZE - toff;
452 if (vm_page_trysbusy(tbp->b_pages[j]) == 0)
454 if ((tbp->b_pages[j]->valid &
455 vm_page_bits(toff, tinc)) != 0) {
456 vm_page_sunbusy(tbp->b_pages[j]);
459 vm_object_pip_add(tbp->b_bufobj->bo_object, 1);
465 vm_object_pip_wakeupn(tbp->b_bufobj->bo_object,
467 for (k = 0; k < j; k++)
468 vm_page_sunbusy(tbp->b_pages[k]);
474 * Set a read-ahead mark as appropriate
476 if ((fbp && (i == 1)) || (i == (run - 1)))
477 tbp->b_flags |= B_RAM;
480 * Set the buffer up for an async read (XXX should
481 * we do this only if we do not wind up brelse()ing?).
482 * Set the block number if it isn't set, otherwise
483 * if it is make sure it matches the block number we
486 tbp->b_flags |= B_ASYNC;
487 tbp->b_iocmd = BIO_READ;
488 if (tbp->b_blkno == tbp->b_lblkno) {
490 } else if (tbp->b_blkno != bn) {
495 * XXX fbp from caller may not be B_ASYNC, but we are going
496 * to biodone() it in cluster_callback() anyway
499 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
500 tbp, b_cluster.cluster_entry);
501 for (j = 0; j < tbp->b_npages; j += 1) {
505 if ((bp->b_npages == 0) ||
506 (bp->b_pages[bp->b_npages-1] != m)) {
507 bp->b_pages[bp->b_npages] = m;
510 if (vm_page_all_valid(m))
511 tbp->b_pages[j] = bogus_page;
515 * Don't inherit tbp->b_bufsize as it may be larger due to
516 * a non-page-aligned size. Instead just aggregate using
519 if (tbp->b_bcount != size)
520 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size);
521 if (tbp->b_bufsize != size)
522 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size);
523 bp->b_bcount += size;
524 bp->b_bufsize += size;
528 * Fully valid pages in the cluster are already good and do not need
529 * to be re-read from disk. Replace the page with bogus_page
531 for (j = 0; j < bp->b_npages; j++) {
532 if (vm_page_all_valid(bp->b_pages[j]))
533 bp->b_pages[j] = bogus_page;
535 if (bp->b_bufsize > bp->b_kvasize)
536 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
537 bp->b_bufsize, bp->b_kvasize);
539 if (buf_mapped(bp)) {
540 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
541 (vm_page_t *)bp->b_pages, bp->b_npages);
547 * Cleanup after a clustered read or write.
548 * This is complicated by the fact that any of the buffers might have
549 * extra memory (if there were no empty buffer headers at allocbuf time)
550 * that we will need to shift around.
553 cluster_callback(struct buf *bp)
555 struct buf *nbp, *tbp;
559 * Must propagate errors to all the components.
561 if (bp->b_ioflags & BIO_ERROR)
564 if (buf_mapped(bp)) {
565 pmap_qremove(trunc_page((vm_offset_t) bp->b_data),
569 * Move memory from the large cluster buffer into the component
570 * buffers and mark IO as done on these.
572 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head);
574 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry);
576 tbp->b_ioflags |= BIO_ERROR;
577 tbp->b_error = error;
579 tbp->b_dirtyoff = tbp->b_dirtyend = 0;
580 tbp->b_flags &= ~B_INVAL;
581 tbp->b_ioflags &= ~BIO_ERROR;
583 * XXX the bdwrite()/bqrelse() issued during
584 * cluster building clears B_RELBUF (see bqrelse()
585 * comment). If direct I/O was specified, we have
586 * to restore it here to allow the buffer and VM
589 if (tbp->b_flags & B_DIRECT)
590 tbp->b_flags |= B_RELBUF;
595 uma_zfree(cluster_pbuf_zone, bp);
601 * Implement modified write build for cluster.
603 * write_behind = 0 write behind disabled
604 * write_behind = 1 write behind normal (default)
605 * write_behind = 2 write behind backed-off
609 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len,
614 switch (write_behind) {
621 r = cluster_wbuild(vp, size, start_lbn, len, gbflags);
631 * Do clustered write for FFS.
634 * 1. Write is not sequential (write asynchronously)
635 * Write is sequential:
636 * 2. beginning of cluster - begin cluster
637 * 3. middle of a cluster - add to cluster
638 * 4. end of a cluster - asynchronously write cluster
641 cluster_write(struct vnode *vp, struct vn_clusterw *vnc, struct buf *bp,
642 u_quad_t filesize, int seqcount, int gbflags)
645 int maxclen, cursize;
649 if (!unmapped_buf_allowed)
650 gbflags &= ~GB_UNMAPPED;
652 if (vp->v_type == VREG) {
653 async = DOINGASYNC(vp);
654 lblocksize = vp->v_mount->mnt_stat.f_iosize;
657 lblocksize = bp->b_bufsize;
660 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset"));
662 /* Initialize vnode to beginning of file. */
664 vnc->v_lasta = vnc->v_clen = vnc->v_cstart = vnc->v_lastw = 0;
666 if (vnc->v_clen == 0 || lbn != vnc->v_lastw + 1 ||
667 (bp->b_blkno != vnc->v_lasta + btodb(lblocksize))) {
668 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1;
669 if (vnc->v_clen != 0) {
671 * Next block is not sequential.
673 * If we are not writing at end of file, the process
674 * seeked to another point in the file since its last
675 * write, or we have reached our maximum cluster size,
676 * then push the previous cluster. Otherwise try
677 * reallocating to make it sequential.
679 * Change to algorithm: only push previous cluster if
680 * it was sequential from the point of view of the
681 * seqcount heuristic, otherwise leave the buffer
682 * intact so we can potentially optimize the I/O
683 * later on in the buf_daemon or update daemon
686 cursize = vnc->v_lastw - vnc->v_cstart + 1;
687 if ((u_quad_t)bp->b_offset + lblocksize != filesize ||
688 lbn != vnc->v_lastw + 1 || vnc->v_clen <= cursize) {
689 if (!async && seqcount > 0) {
690 cluster_wbuild_wb(vp, lblocksize,
691 vnc->v_cstart, cursize, gbflags);
694 struct buf **bpp, **endbp;
695 struct cluster_save *buflist;
697 buflist = cluster_collectbufs(vp, vnc, bp,
699 if (buflist == NULL) {
701 * Cluster build failed so just write
707 endbp = &buflist->bs_children
708 [buflist->bs_nchildren - 1];
709 if (VOP_REALLOCBLKS(vp, buflist)) {
711 * Failed, push the previous cluster
712 * if *really* writing sequentially
713 * in the logical file (seqcount > 1),
714 * otherwise delay it in the hopes that
715 * the low level disk driver can
716 * optimize the write ordering.
718 for (bpp = buflist->bs_children;
721 free(buflist, M_SEGMENT);
723 cluster_wbuild_wb(vp,
724 lblocksize, vnc->v_cstart,
729 * Succeeded, keep building cluster.
731 for (bpp = buflist->bs_children;
734 free(buflist, M_SEGMENT);
736 vnc->v_lasta = bp->b_blkno;
742 * Consider beginning a cluster. If at end of file, make
743 * cluster as large as possible, otherwise find size of
746 if (vp->v_type == VREG &&
747 (u_quad_t) bp->b_offset + lblocksize != filesize &&
748 bp->b_blkno == bp->b_lblkno &&
749 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen,
750 NULL) != 0 || bp->b_blkno == -1)) {
755 vnc->v_cstart = lbn + 1;
759 vnc->v_clen = maxclen;
761 if (!async && maxclen == 0) { /* I/O not contiguous */
762 vnc->v_cstart = lbn + 1;
764 } else { /* Wait for rest of cluster */
768 } else if (lbn == vnc->v_cstart + vnc->v_clen) {
770 * At end of cluster, write it out if seqcount tells us we
771 * are operating sequentially, otherwise let the buf or
772 * update daemon handle it.
777 cluster_wbuild_wb(vp, lblocksize, vnc->v_cstart,
778 vnc->v_clen + 1, gbflags);
781 vnc->v_cstart = lbn + 1;
782 } else if (vm_page_count_severe()) {
784 * We are low on memory, get it going NOW
790 * In the middle of a cluster, so just delay the I/O for now.
800 * This is an awful lot like cluster_rbuild...wish they could be combined.
801 * The last lbn argument is the current block on which I/O is being
802 * performed. Check to see that it doesn't fall in the middle of
803 * the current block (if last_bp == NULL).
806 cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len,
809 struct buf *bp, *tbp;
812 int totalwritten = 0;
813 int dbsize = btodb(size);
815 if (!unmapped_buf_allowed)
816 gbflags &= ~GB_UNMAPPED;
821 * If the buffer is not delayed-write (i.e. dirty), or it
822 * is delayed-write but either locked or inval, it cannot
823 * partake in the clustered write.
826 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL ||
827 (tbp->b_vflags & BV_BKGRDINPROG)) {
834 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, BO_LOCKPTR(bo))) {
839 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) {
846 tbp->b_flags &= ~B_DONE;
849 * Extra memory in the buffer, punt on this buffer.
850 * XXX we could handle this in most cases, but we would
851 * have to push the extra memory down to after our max
852 * possible cluster size and then potentially pull it back
853 * up if the cluster was terminated prematurely--too much
856 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) !=
857 (B_CLUSTEROK | B_VMIO)) ||
858 (tbp->b_bcount != tbp->b_bufsize) ||
859 (tbp->b_bcount != size) ||
861 ((bp = uma_zalloc(cluster_pbuf_zone, M_NOWAIT)) == NULL)) {
862 totalwritten += tbp->b_bufsize;
868 MPASS((bp->b_flags & B_MAXPHYS) != 0);
871 * We got a pbuf to make the cluster in.
874 TAILQ_INIT(&bp->b_cluster.cluster_head);
878 if (tbp->b_wcred != NOCRED)
879 bp->b_wcred = crhold(tbp->b_wcred);
881 bp->b_blkno = tbp->b_blkno;
882 bp->b_lblkno = tbp->b_lblkno;
883 bp->b_offset = tbp->b_offset;
886 * We are synthesizing a buffer out of vm_page_t's, but
887 * if the block size is not page aligned then the starting
888 * address may not be either. Inherit the b_data offset
889 * from the original buffer.
891 if ((gbflags & GB_UNMAPPED) == 0 ||
892 (tbp->b_flags & B_VMIO) == 0) {
893 bp->b_data = (char *)((vm_offset_t)bp->b_data |
894 ((vm_offset_t)tbp->b_data & PAGE_MASK));
896 bp->b_data = unmapped_buf;
898 bp->b_flags |= B_CLUSTER | (tbp->b_flags & (B_VMIO |
900 bp->b_iodone = cluster_callback;
903 * From this location in the file, scan forward to see
904 * if there are buffers with adjacent data that need to
905 * be written as well.
907 for (i = 0; i < len; ++i, ++start_lbn) {
908 if (i != 0) { /* If not the first buffer */
910 * If the adjacent data is not even in core it
911 * can't need to be written.
914 if ((tbp = gbincore(bo, start_lbn)) == NULL ||
915 (tbp->b_vflags & BV_BKGRDINPROG)) {
921 * If it IS in core, but has different
922 * characteristics, or is locked (which
923 * means it could be undergoing a background
924 * I/O or be in a weird state), then don't
928 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK,
932 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK |
933 B_INVAL | B_DELWRI | B_NEEDCOMMIT))
934 != (B_DELWRI | B_CLUSTEROK |
935 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) ||
936 tbp->b_wcred != bp->b_wcred) {
942 * Check that the combined cluster
943 * would make sense with regard to pages
944 * and would not be too large
946 if ((tbp->b_bcount != size) ||
947 ((bp->b_blkno + (dbsize * i)) !=
949 ((tbp->b_npages + bp->b_npages) >
950 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) {
956 * Ok, it's passed all the tests,
957 * so remove it from the free list
958 * and mark it busy. We will use it.
961 tbp->b_flags &= ~B_DONE;
962 } /* end of code for non-first buffers only */
964 * If the IO is via the VM then we do some
965 * special VM hackery (yuck). Since the buffer's
966 * block size may not be page-aligned it is possible
967 * for a page to be shared between two buffers. We
968 * have to get rid of the duplication when building
971 if (tbp->b_flags & B_VMIO) {
975 vfs_busy_pages_acquire(tbp);
976 } else { /* if not first buffer */
977 for (j = 0; j < tbp->b_npages; j += 1) {
979 if (vm_page_trysbusy(m) == 0) {
980 for (j--; j >= 0; j--)
988 vm_object_pip_add(tbp->b_bufobj->bo_object,
990 for (j = 0; j < tbp->b_npages; j += 1) {
992 if ((bp->b_npages == 0) ||
993 (bp->b_pages[bp->b_npages - 1] != m)) {
994 bp->b_pages[bp->b_npages] = m;
999 bp->b_bcount += size;
1000 bp->b_bufsize += size;
1002 * If any of the clustered buffers have their
1003 * B_BARRIER flag set, transfer that request to
1006 bp->b_flags |= (tbp->b_flags & B_BARRIER);
1007 tbp->b_flags &= ~(B_DONE | B_BARRIER);
1008 tbp->b_flags |= B_ASYNC;
1009 tbp->b_ioflags &= ~BIO_ERROR;
1010 tbp->b_iocmd = BIO_WRITE;
1012 reassignbuf(tbp); /* put on clean list */
1013 bufobj_wref(tbp->b_bufobj);
1015 buf_track(tbp, __func__);
1016 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
1017 tbp, b_cluster.cluster_entry);
1020 if (buf_mapped(bp)) {
1021 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
1022 (vm_page_t *)bp->b_pages, bp->b_npages);
1024 if (bp->b_bufsize > bp->b_kvasize)
1026 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
1027 bp->b_bufsize, bp->b_kvasize);
1028 totalwritten += bp->b_bufsize;
1030 bp->b_dirtyend = bp->b_bufsize;
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 vn_clusterw *vnc,
1044 struct buf *last_bp, int gbflags)
1046 struct cluster_save *buflist;
1049 int i, j, len, error;
1051 len = vnc->v_lastw - vnc->v_cstart + 1;
1052 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
1053 M_SEGMENT, M_WAITOK);
1054 buflist->bs_nchildren = 0;
1055 buflist->bs_children = (struct buf **) (buflist + 1);
1056 for (lbn = vnc->v_cstart, i = 0; i < len; lbn++, i++) {
1057 error = bread_gb(vp, lbn, last_bp->b_bcount, NOCRED,
1061 * If read fails, release collected buffers
1062 * and return failure.
1064 for (j = 0; j < i; j++)
1065 brelse(buflist->bs_children[j]);
1066 free(buflist, M_SEGMENT);
1069 buflist->bs_children[i] = bp;
1070 if (bp->b_blkno == bp->b_lblkno)
1071 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno,
1074 buflist->bs_children[i] = bp = last_bp;
1075 if (bp->b_blkno == bp->b_lblkno)
1076 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL);
1077 buflist->bs_nchildren = i + 1;
1082 cluster_init_vn(struct vn_clusterw *vnc)