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. 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.
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
31 * @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
37 #include "opt_debug_cluster.h"
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/kernel.h>
45 #include <sys/vnode.h>
46 #include <sys/malloc.h>
47 #include <sys/mount.h>
48 #include <sys/racct.h>
49 #include <sys/resourcevar.h>
50 #include <sys/rwlock.h>
51 #include <sys/vmmeter.h>
53 #include <vm/vm_object.h>
54 #include <vm/vm_page.h>
55 #include <sys/sysctl.h>
57 #if defined(CLUSTERDEBUG)
58 static int rcluster= 0;
59 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0,
60 "Debug VFS clustering code");
63 static MALLOC_DEFINE(M_SEGMENT, "cl_savebuf", "cluster_save buffer");
65 static struct cluster_save *cluster_collectbufs(struct vnode *vp,
66 struct buf *last_bp, int gbflags);
67 static struct buf *cluster_rbuild(struct vnode *vp, u_quad_t filesize,
68 daddr_t lbn, daddr_t blkno, long size, int run, int gbflags,
70 static void cluster_callback(struct buf *);
72 static int write_behind = 1;
73 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0,
74 "Cluster write-behind; 0: disable, 1: enable, 2: backed off");
76 static int read_max = 64;
77 SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0,
78 "Cluster read-ahead max block count");
80 static int read_min = 1;
81 SYSCTL_INT(_vfs, OID_AUTO, read_min, CTLFLAG_RW, &read_min, 0,
82 "Cluster read min block count");
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;
95 daddr_t blkno, origblkno;
102 if (!unmapped_buf_allowed)
103 gbflags &= ~GB_UNMAPPED;
106 * Try to limit the amount of read-ahead by a few
107 * ad-hoc parameters. This needs work!!!
109 racluster = vp->v_mount->mnt_iosize_max / size;
111 maxra = min(read_max, maxra);
112 maxra = min(nbuf/8, maxra);
113 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize)
114 maxra = (filesize / size) - lblkno;
117 * get the requested block
119 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, gbflags);
125 * if it is in the cache, then check to see if the reads have been
126 * sequential. If they have, then try some read-ahead, otherwise
127 * back-off on prospective read-aheads.
129 if (bp->b_flags & B_CACHE) {
132 } else if ((bp->b_flags & B_RAM) == 0) {
135 bp->b_flags &= ~B_RAM;
137 for (i = 1; i < maxra; i++) {
139 * Stop if the buffer does not exist or it
140 * is invalid (about to go away?)
142 rbp = gbincore(&vp->v_bufobj, lblkno+i);
143 if (rbp == NULL || (rbp->b_flags & B_INVAL))
147 * Set another read-ahead mark so we know
148 * to check again. (If we can lock the
149 * buffer without waiting)
151 if ((((i % racluster) == (racluster - 1)) ||
153 && (0 == BUF_LOCK(rbp,
154 LK_EXCLUSIVE | LK_NOWAIT, NULL))) {
155 rbp->b_flags |= B_RAM;
167 * If it isn't in the cache, then get a chunk from
168 * disk if sequential, otherwise just get the block.
171 off_t firstread = bp->b_offset;
175 KASSERT(bp->b_offset != NOOFFSET,
176 ("cluster_read: no buffer offset"));
181 * Adjust totread if needed
183 minread = read_min * size;
184 if (minread > totread)
188 * Compute the total number of blocks that we should read
191 if (firstread + totread > filesize)
192 totread = filesize - firstread;
193 nblks = howmany(totread, size);
194 if (nblks > racluster)
198 * Now compute the number of contiguous blocks.
201 error = VOP_BMAP(vp, lblkno, NULL,
202 &blkno, &ncontig, NULL);
204 * If this failed to map just do the original block.
206 if (error || blkno == -1)
211 * If we have contiguous data available do a cluster
212 * otherwise just read the requested block.
215 /* Account for our first block. */
216 ncontig = min(ncontig + 1, nblks);
219 bp = cluster_rbuild(vp, filesize, lblkno,
220 blkno, size, nblks, gbflags, bp);
221 lblkno += (bp->b_bufsize / size);
223 bp->b_flags |= B_RAM;
224 bp->b_iocmd = BIO_READ;
230 * handle the synchronous read so that it is available ASAP.
233 if ((bp->b_flags & B_CLUSTER) == 0) {
234 vfs_busy_pages(bp, 0);
236 bp->b_flags &= ~B_INVAL;
237 bp->b_ioflags &= ~BIO_ERROR;
238 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL)
240 bp->b_iooffset = dbtob(bp->b_blkno);
245 racct_add_buf(curproc, bp, 0);
246 PROC_UNLOCK(curproc);
249 curthread->td_ru.ru_inblock++;
253 * If we have been doing sequential I/O, then do some read-ahead.
255 while (lblkno < (origblkno + maxra)) {
256 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL);
264 * We could throttle ncontig here by maxra but we might as
265 * well read the data if it is contiguous. We're throttled
266 * by racluster anyway.
269 ncontig = min(ncontig + 1, racluster);
270 rbp = cluster_rbuild(vp, filesize, lblkno, blkno,
271 size, ncontig, gbflags, NULL);
272 lblkno += (rbp->b_bufsize / size);
273 if (rbp->b_flags & B_DELWRI) {
278 rbp = getblk(vp, lblkno, size, 0, 0, gbflags);
280 if (rbp->b_flags & B_DELWRI) {
284 rbp->b_flags |= B_ASYNC | B_RAM;
285 rbp->b_iocmd = BIO_READ;
286 rbp->b_blkno = blkno;
288 if (rbp->b_flags & B_CACHE) {
289 rbp->b_flags &= ~B_ASYNC;
293 if ((rbp->b_flags & B_CLUSTER) == 0) {
294 vfs_busy_pages(rbp, 0);
296 rbp->b_flags &= ~B_INVAL;
297 rbp->b_ioflags &= ~BIO_ERROR;
298 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL)
300 rbp->b_iooffset = dbtob(rbp->b_blkno);
305 racct_add_buf(curproc, rbp, 0);
306 PROC_UNLOCK(curproc);
309 curthread->td_ru.ru_inblock++;
314 * Like bread, always brelse() the buffer when
315 * returning an error.
317 error = bufwait(reqbp);
327 * If blocks are contiguous on disk, use this to provide clustered
328 * read ahead. We will read as many blocks as possible sequentially
329 * and then parcel them up into logical blocks in the buffer hash table.
332 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn,
333 daddr_t blkno, long size, int run, int gbflags, struct buf *fbp)
335 struct buf *bp, *tbp;
339 int i, inc, j, k, toff;
341 KASSERT(size == vp->v_mount->mnt_stat.f_iosize,
342 ("cluster_rbuild: size %ld != f_iosize %jd\n",
343 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize));
348 while ((u_quad_t) size * (lbn + run) > filesize) {
354 tbp->b_iocmd = BIO_READ;
356 tbp = getblk(vp, lbn, size, 0, 0, gbflags);
357 if (tbp->b_flags & B_CACHE)
359 tbp->b_flags |= B_ASYNC | B_RAM;
360 tbp->b_iocmd = BIO_READ;
362 tbp->b_blkno = blkno;
363 if( (tbp->b_flags & B_MALLOC) ||
364 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) )
367 bp = trypbuf(&cluster_pbuf_freecnt);
372 * We are synthesizing a buffer out of vm_page_t's, but
373 * if the block size is not page aligned then the starting
374 * address may not be either. Inherit the b_data offset
375 * from the original buffer.
377 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO;
378 if ((gbflags & GB_UNMAPPED) != 0) {
379 bp->b_data = unmapped_buf;
381 bp->b_data = (char *)((vm_offset_t)bp->b_data |
382 ((vm_offset_t)tbp->b_data & PAGE_MASK));
384 bp->b_iocmd = BIO_READ;
385 bp->b_iodone = cluster_callback;
388 bp->b_offset = tbp->b_offset;
389 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset"));
392 TAILQ_INIT(&bp->b_cluster.cluster_head);
399 for (bn = blkno, i = 0; i < run; ++i, bn += inc) {
401 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object);
402 vfs_drain_busy_pages(tbp);
403 vm_object_pip_add(tbp->b_bufobj->bo_object,
405 for (k = 0; k < tbp->b_npages; k++)
406 vm_page_sbusy(tbp->b_pages[k]);
407 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object);
409 if ((bp->b_npages * PAGE_SIZE) +
410 round_page(size) > vp->v_mount->mnt_iosize_max) {
414 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT |
415 (gbflags & GB_UNMAPPED));
417 /* Don't wait around for locked bufs. */
422 * Stop scanning if the buffer is fully valid
423 * (marked B_CACHE), or locked (may be doing a
424 * background write), or if the buffer is not
425 * VMIO backed. The clustering code can only deal
426 * with VMIO-backed buffers. The bo lock is not
427 * required for the BKGRDINPROG check since it
428 * can not be set without the buf lock.
430 if ((tbp->b_vflags & BV_BKGRDINPROG) ||
431 (tbp->b_flags & B_CACHE) ||
432 (tbp->b_flags & B_VMIO) == 0) {
438 * The buffer must be completely invalid in order to
439 * take part in the cluster. If it is partially valid
444 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object);
445 for (j = 0; tsize > 0; j++) {
446 toff = off & PAGE_MASK;
448 if (toff + tinc > PAGE_SIZE)
449 tinc = PAGE_SIZE - toff;
450 VM_OBJECT_ASSERT_WLOCKED(tbp->b_pages[j]->object);
451 if ((tbp->b_pages[j]->valid &
452 vm_page_bits(toff, tinc)) != 0)
454 if (vm_page_xbusied(tbp->b_pages[j]))
456 vm_object_pip_add(tbp->b_bufobj->bo_object, 1);
457 vm_page_sbusy(tbp->b_pages[j]);
463 vm_object_pip_add(tbp->b_bufobj->bo_object, -j);
464 for (k = 0; k < j; k++)
465 vm_page_sunbusy(tbp->b_pages[k]);
466 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object);
470 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object);
473 * Set a read-ahead mark as appropriate
475 if ((fbp && (i == 1)) || (i == (run - 1)))
476 tbp->b_flags |= B_RAM;
479 * Set the buffer up for an async read (XXX should
480 * we do this only if we do not wind up brelse()ing?).
481 * Set the block number if it isn't set, otherwise
482 * if it is make sure it matches the block number we
485 tbp->b_flags |= B_ASYNC;
486 tbp->b_iocmd = BIO_READ;
487 if (tbp->b_blkno == tbp->b_lblkno) {
489 } else if (tbp->b_blkno != bn) {
490 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object);
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 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object);
502 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 (m->valid == VM_PAGE_BITS_ALL)
511 tbp->b_pages[j] = bogus_page;
513 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object);
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 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object);
532 for (j = 0; j < bp->b_npages; j++) {
533 VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[j]->object);
534 if (bp->b_pages[j]->valid == VM_PAGE_BITS_ALL)
535 bp->b_pages[j] = bogus_page;
537 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object);
538 if (bp->b_bufsize > bp->b_kvasize)
539 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
540 bp->b_bufsize, bp->b_kvasize);
542 if (buf_mapped(bp)) {
543 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
544 (vm_page_t *)bp->b_pages, bp->b_npages);
550 * Cleanup after a clustered read or write.
551 * This is complicated by the fact that any of the buffers might have
552 * extra memory (if there were no empty buffer headers at allocbuf time)
553 * that we will need to shift around.
559 struct buf *nbp, *tbp;
563 * Must propagate errors to all the components.
565 if (bp->b_ioflags & BIO_ERROR)
568 if (buf_mapped(bp)) {
569 pmap_qremove(trunc_page((vm_offset_t) bp->b_data),
573 * Move memory from the large cluster buffer into the component
574 * buffers and mark IO as done on these.
576 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head);
578 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry);
580 tbp->b_ioflags |= BIO_ERROR;
581 tbp->b_error = error;
583 tbp->b_dirtyoff = tbp->b_dirtyend = 0;
584 tbp->b_flags &= ~B_INVAL;
585 tbp->b_ioflags &= ~BIO_ERROR;
587 * XXX the bdwrite()/bqrelse() issued during
588 * cluster building clears B_RELBUF (see bqrelse()
589 * comment). If direct I/O was specified, we have
590 * to restore it here to allow the buffer and VM
593 if (tbp->b_flags & B_DIRECT)
594 tbp->b_flags |= B_RELBUF;
599 relpbuf(bp, &cluster_pbuf_freecnt);
605 * Implement modified write build for cluster.
607 * write_behind = 0 write behind disabled
608 * write_behind = 1 write behind normal (default)
609 * write_behind = 2 write behind backed-off
613 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len,
618 switch (write_behind) {
625 r = cluster_wbuild(vp, size, start_lbn, len, gbflags);
635 * Do clustered write for FFS.
638 * 1. Write is not sequential (write asynchronously)
639 * Write is sequential:
640 * 2. beginning of cluster - begin cluster
641 * 3. middle of a cluster - add to cluster
642 * 4. end of a cluster - asynchronously write cluster
645 cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount,
649 int maxclen, cursize;
653 if (!unmapped_buf_allowed)
654 gbflags &= ~GB_UNMAPPED;
656 if (vp->v_type == VREG) {
657 async = DOINGASYNC(vp);
658 lblocksize = vp->v_mount->mnt_stat.f_iosize;
661 lblocksize = bp->b_bufsize;
664 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset"));
666 /* Initialize vnode to beginning of file. */
668 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
670 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 ||
671 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) {
672 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1;
673 if (vp->v_clen != 0) {
675 * Next block is not sequential.
677 * If we are not writing at end of file, the process
678 * seeked to another point in the file since its last
679 * write, or we have reached our maximum cluster size,
680 * then push the previous cluster. Otherwise try
681 * reallocating to make it sequential.
683 * Change to algorithm: only push previous cluster if
684 * it was sequential from the point of view of the
685 * seqcount heuristic, otherwise leave the buffer
686 * intact so we can potentially optimize the I/O
687 * later on in the buf_daemon or update daemon
690 cursize = vp->v_lastw - vp->v_cstart + 1;
691 if (((u_quad_t) bp->b_offset + lblocksize) != filesize ||
692 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) {
693 if (!async && seqcount > 0) {
694 cluster_wbuild_wb(vp, lblocksize,
695 vp->v_cstart, cursize, gbflags);
698 struct buf **bpp, **endbp;
699 struct cluster_save *buflist;
701 buflist = cluster_collectbufs(vp, bp, gbflags);
702 endbp = &buflist->bs_children
703 [buflist->bs_nchildren - 1];
704 if (VOP_REALLOCBLKS(vp, buflist)) {
706 * Failed, push the previous cluster
707 * if *really* writing sequentially
708 * in the logical file (seqcount > 1),
709 * otherwise delay it in the hopes that
710 * the low level disk driver can
711 * optimize the write ordering.
713 for (bpp = buflist->bs_children;
716 free(buflist, M_SEGMENT);
718 cluster_wbuild_wb(vp,
719 lblocksize, vp->v_cstart,
724 * Succeeded, keep building cluster.
726 for (bpp = buflist->bs_children;
729 free(buflist, M_SEGMENT);
731 vp->v_lasta = bp->b_blkno;
737 * Consider beginning a cluster. If at end of file, make
738 * cluster as large as possible, otherwise find size of
741 if ((vp->v_type == VREG) &&
742 ((u_quad_t) bp->b_offset + lblocksize) != filesize &&
743 (bp->b_blkno == bp->b_lblkno) &&
744 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) ||
745 bp->b_blkno == -1)) {
748 vp->v_lasta = bp->b_blkno;
749 vp->v_cstart = lbn + 1;
753 vp->v_clen = maxclen;
754 if (!async && maxclen == 0) { /* I/O not contiguous */
755 vp->v_cstart = lbn + 1;
757 } else { /* Wait for rest of cluster */
761 } else if (lbn == vp->v_cstart + vp->v_clen) {
763 * At end of cluster, write it out if seqcount tells us we
764 * are operating sequentially, otherwise let the buf or
765 * update daemon handle it.
769 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart,
770 vp->v_clen + 1, gbflags);
773 vp->v_cstart = lbn + 1;
774 } else if (vm_page_count_severe()) {
776 * We are low on memory, get it going NOW
781 * In the middle of a cluster, so just delay the I/O for now.
786 vp->v_lasta = bp->b_blkno;
791 * This is an awful lot like cluster_rbuild...wish they could be combined.
792 * The last lbn argument is the current block on which I/O is being
793 * performed. Check to see that it doesn't fall in the middle of
794 * the current block (if last_bp == NULL).
797 cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len,
800 struct buf *bp, *tbp;
803 int totalwritten = 0;
804 int dbsize = btodb(size);
806 if (!unmapped_buf_allowed)
807 gbflags &= ~GB_UNMAPPED;
812 * If the buffer is not delayed-write (i.e. dirty), or it
813 * is delayed-write but either locked or inval, it cannot
814 * partake in the clustered write.
817 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL ||
818 (tbp->b_vflags & BV_BKGRDINPROG)) {
825 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, BO_LOCKPTR(bo))) {
830 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) {
837 tbp->b_flags &= ~B_DONE;
840 * Extra memory in the buffer, punt on this buffer.
841 * XXX we could handle this in most cases, but we would
842 * have to push the extra memory down to after our max
843 * possible cluster size and then potentially pull it back
844 * up if the cluster was terminated prematurely--too much
847 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) !=
848 (B_CLUSTEROK | B_VMIO)) ||
849 (tbp->b_bcount != tbp->b_bufsize) ||
850 (tbp->b_bcount != size) ||
852 ((bp = (vp->v_vflag & VV_MD) != 0 ?
853 trypbuf(&cluster_pbuf_freecnt) :
854 getpbuf(&cluster_pbuf_freecnt)) == NULL)) {
855 totalwritten += tbp->b_bufsize;
863 * We got a pbuf to make the cluster in.
866 TAILQ_INIT(&bp->b_cluster.cluster_head);
870 if (tbp->b_wcred != NOCRED)
871 bp->b_wcred = crhold(tbp->b_wcred);
873 bp->b_blkno = tbp->b_blkno;
874 bp->b_lblkno = tbp->b_lblkno;
875 bp->b_offset = tbp->b_offset;
878 * We are synthesizing a buffer out of vm_page_t's, but
879 * if the block size is not page aligned then the starting
880 * address may not be either. Inherit the b_data offset
881 * from the original buffer.
883 if ((gbflags & GB_UNMAPPED) == 0 ||
884 (tbp->b_flags & B_VMIO) == 0) {
885 bp->b_data = (char *)((vm_offset_t)bp->b_data |
886 ((vm_offset_t)tbp->b_data & PAGE_MASK));
888 bp->b_data = unmapped_buf;
890 bp->b_flags |= B_CLUSTER | (tbp->b_flags & (B_VMIO |
892 bp->b_iodone = cluster_callback;
895 * From this location in the file, scan forward to see
896 * if there are buffers with adjacent data that need to
897 * be written as well.
899 for (i = 0; i < len; ++i, ++start_lbn) {
900 if (i != 0) { /* If not the first buffer */
902 * If the adjacent data is not even in core it
903 * can't need to be written.
906 if ((tbp = gbincore(bo, start_lbn)) == NULL ||
907 (tbp->b_vflags & BV_BKGRDINPROG)) {
913 * If it IS in core, but has different
914 * characteristics, or is locked (which
915 * means it could be undergoing a background
916 * I/O or be in a weird state), then don't
920 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK,
924 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK |
925 B_INVAL | B_DELWRI | B_NEEDCOMMIT))
926 != (B_DELWRI | B_CLUSTEROK |
927 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) ||
928 tbp->b_wcred != bp->b_wcred) {
934 * Check that the combined cluster
935 * would make sense with regard to pages
936 * and would not be too large
938 if ((tbp->b_bcount != size) ||
939 ((bp->b_blkno + (dbsize * i)) !=
941 ((tbp->b_npages + bp->b_npages) >
942 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) {
948 * Ok, it's passed all the tests,
949 * so remove it from the free list
950 * and mark it busy. We will use it.
953 tbp->b_flags &= ~B_DONE;
954 } /* end of code for non-first buffers only */
956 * If the IO is via the VM then we do some
957 * special VM hackery (yuck). Since the buffer's
958 * block size may not be page-aligned it is possible
959 * for a page to be shared between two buffers. We
960 * have to get rid of the duplication when building
963 if (tbp->b_flags & B_VMIO) {
966 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object);
968 vfs_drain_busy_pages(tbp);
969 } else { /* if not first buffer */
970 for (j = 0; j < tbp->b_npages; j += 1) {
972 if (vm_page_xbusied(m)) {
980 for (j = 0; j < tbp->b_npages; j += 1) {
983 vm_object_pip_add(m->object, 1);
984 if ((bp->b_npages == 0) ||
985 (bp->b_pages[bp->b_npages - 1] != m)) {
986 bp->b_pages[bp->b_npages] = m;
990 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object);
992 bp->b_bcount += size;
993 bp->b_bufsize += size;
995 * If any of the clustered buffers have their
996 * B_BARRIER flag set, transfer that request to
999 bp->b_flags |= (tbp->b_flags & B_BARRIER);
1000 tbp->b_flags &= ~(B_DONE | B_BARRIER);
1001 tbp->b_flags |= B_ASYNC;
1002 tbp->b_ioflags &= ~BIO_ERROR;
1003 tbp->b_iocmd = BIO_WRITE;
1005 reassignbuf(tbp); /* put on clean list */
1006 bufobj_wref(tbp->b_bufobj);
1008 buf_track(tbp, __func__);
1009 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
1010 tbp, b_cluster.cluster_entry);
1013 if (buf_mapped(bp)) {
1014 pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
1015 (vm_page_t *)bp->b_pages, bp->b_npages);
1017 if (bp->b_bufsize > bp->b_kvasize)
1019 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n",
1020 bp->b_bufsize, bp->b_kvasize);
1021 totalwritten += bp->b_bufsize;
1023 bp->b_dirtyend = bp->b_bufsize;
1028 return totalwritten;
1032 * Collect together all the buffers in a cluster.
1033 * Plus add one additional buffer.
1035 static struct cluster_save *
1036 cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int gbflags)
1038 struct cluster_save *buflist;
1043 len = vp->v_lastw - vp->v_cstart + 1;
1044 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
1045 M_SEGMENT, M_WAITOK);
1046 buflist->bs_nchildren = 0;
1047 buflist->bs_children = (struct buf **) (buflist + 1);
1048 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) {
1049 (void)bread_gb(vp, lbn, last_bp->b_bcount, NOCRED,
1051 buflist->bs_children[i] = bp;
1052 if (bp->b_blkno == bp->b_lblkno)
1053 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno,
1056 buflist->bs_children[i] = bp = last_bp;
1057 if (bp->b_blkno == bp->b_lblkno)
1058 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL);
1059 buflist->bs_nchildren = i + 1;