freebsd-skq/sys/kern/vfs_cluster.c
Bruce Evans b5e8ce9f12 Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) and most of the warnings from
`gcc -Wnested-externs'.  Fix all the bugs found.  There were no serious
ones.
1995-03-16 18:17:34 +00:00

661 lines
17 KiB
C

/*-
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
* Modifications/enhancements:
* Copyright (c) 1995 John S. Dyson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94
* $Id: vfs_cluster.c,v 1.12 1995/03/04 03:24:28 davidg Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/malloc.h>
#include <sys/resourcevar.h>
#include <sys/vmmeter.h>
#include <miscfs/specfs/specdev.h>
#include <vm/vm.h>
#include <vm/vm_pageout.h>
#ifdef DEBUG
#include <vm/vm.h>
#include <sys/sysctl.h>
int doreallocblks = 0;
struct ctldebug debug13 = {"doreallocblks", &doreallocblks};
#else
/* XXX for cluster_write */
#define doreallocblks 0
#endif
/*
* Local declarations
*/
struct buf *cluster_rbuild __P((struct vnode *, u_quad_t, struct buf *,
daddr_t, daddr_t, long, int, long));
struct cluster_save *cluster_collectbufs __P((struct vnode *, struct buf *));
int totreads;
int totreadblocks;
#ifdef DIAGNOSTIC
/*
* Set to 1 if reads of block zero should cause readahead to be done.
* Set to 0 treats a read of block zero as a non-sequential read.
*
* Setting to one assumes that most reads of block zero of files are due to
* sequential passes over the files (e.g. cat, sum) where additional blocks
* will soon be needed. Setting to zero assumes that the majority are
* surgical strikes to get particular info (e.g. size, file) where readahead
* blocks will not be used and, in fact, push out other potentially useful
* blocks from the cache. The former seems intuitive, but some quick tests
* showed that the latter performed better from a system-wide point of view.
*/
int doclusterraz = 0;
#define ISSEQREAD(vp, blk) \
(((blk) != 0 || doclusterraz) && \
((blk) == (vp)->v_lastr + 1 || (blk) == (vp)->v_lastr))
#else
#define ISSEQREAD(vp, blk) \
(/* (blk) != 0 && */ ((blk) == (vp)->v_lastr + 1 || (blk) == (vp)->v_lastr))
#endif
/*
* This replaces bread. If this is a bread at the beginning of a file and
* lastr is 0, we assume this is the first read and we'll read up to two
* blocks if they are sequential. After that, we'll do regular read ahead
* in clustered chunks.
* bp is the block requested.
* rbp is the read-ahead block.
* If either is NULL, then you don't have to do the I/O.
*/
int
cluster_read(vp, filesize, lblkno, size, cred, bpp)
struct vnode *vp;
u_quad_t filesize;
daddr_t lblkno;
long size;
struct ucred *cred;
struct buf **bpp;
{
struct buf *bp, *rbp;
daddr_t blkno, rablkno, origlblkno;
long flags;
int error, num_ra, alreadyincore;
origlblkno = lblkno;
error = 0;
/*
* get the requested block
*/
*bpp = bp = getblk(vp, lblkno, size, 0, 0);
/*
* if it is in the cache, then check to see if the reads have been
* sequential. If they have, then try some read-ahead, otherwise
* back-off on prospective read-aheads.
*/
if (bp->b_flags & B_CACHE) {
int i;
if (!ISSEQREAD(vp, origlblkno)) {
vp->v_maxra = bp->b_lblkno + bp->b_bcount / size;
vp->v_ralen >>= 1;
return 0;
} else if( vp->v_maxra >= origlblkno) {
if ((vp->v_ralen + 1) < (MAXPHYS / size))
vp->v_ralen++;
if ( vp->v_maxra >= (origlblkno + vp->v_ralen))
return 0;
lblkno = vp->v_maxra;
}
bp = NULL;
} else {
/*
* if it isn't in the cache, then get a chunk from disk if
* sequential, otherwise just get the block.
*/
bp->b_flags |= B_READ;
lblkno += 1;
curproc->p_stats->p_ru.ru_inblock++; /* XXX */
}
/*
* if ralen is "none", then try a little
*/
if (vp->v_ralen == 0)
vp->v_ralen = 1;
/*
* assume no read-ahead
*/
alreadyincore = 1;
rablkno = lblkno;
/*
* if we have been doing sequential I/O, then do some read-ahead
*/
if (ISSEQREAD(vp, origlblkno)) {
int i;
/*
* this code makes sure that the stuff that we have read-ahead
* is still in the cache. If it isn't, we have been reading
* ahead too much, and we need to back-off, otherwise we might
* try to read more.
*/
for (i = 0; i < vp->v_ralen; i++) {
rablkno = lblkno + i;
alreadyincore = (int) incore(vp, rablkno);
if (!alreadyincore) {
if (rablkno < vp->v_maxra) {
vp->v_maxra = rablkno;
vp->v_ralen >>= 1;
alreadyincore = 1;
} else {
if (inmem(vp, rablkno)) {
if( vp->v_maxra < rablkno)
vp->v_maxra = rablkno + 1;
continue;
}
if ((vp->v_ralen + 1) < MAXPHYS / size)
vp->v_ralen++;
}
break;
} else if( vp->v_maxra < rablkno) {
vp->v_maxra = rablkno + 1;
}
}
}
/*
* we now build the read-ahead buffer if it is desirable.
*/
rbp = NULL;
if (!alreadyincore &&
(rablkno + 1) * size <= filesize &&
!(error = VOP_BMAP(vp, rablkno, NULL, &blkno, &num_ra)) &&
blkno != -1) {
if ((vp->v_ralen + 1) < MAXPHYS / size)
vp->v_ralen++;
if (num_ra > vp->v_ralen)
num_ra = vp->v_ralen;
if (num_ra) {
rbp = cluster_rbuild(vp, filesize,
NULL, rablkno, blkno, size, num_ra, B_READ | B_ASYNC);
} else {
rbp = getblk(vp, rablkno, size, 0, 0);
rbp->b_flags |= B_READ | B_ASYNC;
rbp->b_blkno = blkno;
}
}
/*
* if the synchronous read is a cluster, handle it, otherwise do a
* simple, non-clustered read.
*/
if (bp) {
if (bp->b_flags & (B_DONE | B_DELWRI))
panic("cluster_read: DONE bp");
else {
vfs_busy_pages(bp, 0);
error = VOP_STRATEGY(bp);
vp->v_maxra = bp->b_lblkno + bp->b_bcount / size;
totreads++;
totreadblocks += bp->b_bcount / size;
curproc->p_stats->p_ru.ru_inblock++;
}
}
/*
* and if we have read-aheads, do them too
*/
if (rbp) {
vp->v_maxra = rbp->b_lblkno + rbp->b_bcount / size;
if (error || (rbp->b_flags & B_CACHE)) {
rbp->b_flags &= ~(B_ASYNC | B_READ);
brelse(rbp);
} else {
vfs_busy_pages(rbp, 0);
(void) VOP_STRATEGY(rbp);
totreads++;
totreadblocks += rbp->b_bcount / size;
curproc->p_stats->p_ru.ru_inblock++;
}
}
if (bp && ((bp->b_flags & B_ASYNC) == 0))
return (biowait(bp));
return (error);
}
/*
* If blocks are contiguous on disk, use this to provide clustered
* read ahead. We will read as many blocks as possible sequentially
* and then parcel them up into logical blocks in the buffer hash table.
*/
struct buf *
cluster_rbuild(vp, filesize, bp, lbn, blkno, size, run, flags)
struct vnode *vp;
u_quad_t filesize;
struct buf *bp;
daddr_t lbn;
daddr_t blkno;
long size;
int run;
long flags;
{
struct cluster_save *b_save;
struct buf *tbp;
daddr_t bn;
int i, inc, j;
#ifdef DIAGNOSTIC
if (size != vp->v_mount->mnt_stat.f_iosize)
panic("cluster_rbuild: size %d != filesize %d\n",
size, vp->v_mount->mnt_stat.f_iosize);
#endif
if (size * (lbn + run + 1) > filesize)
--run;
if (run == 0) {
if (!bp) {
bp = getblk(vp, lbn, size, 0, 0);
bp->b_blkno = blkno;
bp->b_flags |= flags;
}
return (bp);
}
tbp = bp;
if (!tbp) {
tbp = getblk(vp, lbn, size, 0, 0);
}
if (tbp->b_flags & B_CACHE) {
return (tbp);
} else if (bp == NULL) {
tbp->b_flags |= B_ASYNC;
}
bp = getpbuf();
bp->b_flags = flags | B_CALL | B_BUSY | B_CLUSTER;
bp->b_iodone = cluster_callback;
bp->b_blkno = blkno;
bp->b_lblkno = lbn;
pbgetvp(vp, bp);
b_save = malloc(sizeof(struct buf *) * (run + 1) + sizeof(struct cluster_save),
M_SEGMENT, M_WAITOK);
b_save->bs_nchildren = 0;
b_save->bs_children = (struct buf **) (b_save + 1);
bp->b_saveaddr = b_save;
bp->b_bcount = 0;
bp->b_bufsize = 0;
bp->b_npages = 0;
if (tbp->b_flags & B_VMIO)
bp->b_flags |= B_VMIO;
inc = btodb(size);
for (bn = blkno, i = 0; i <= run; ++i, bn += inc) {
if (i != 0) {
tbp = getblk(vp, lbn + i, size, 0, 0);
if ((tbp->b_flags & B_CACHE) ||
(tbp->b_flags & B_VMIO) != (bp->b_flags & B_VMIO)) {
brelse(tbp);
break;
}
tbp->b_blkno = bn;
tbp->b_flags |= flags | B_READ | B_ASYNC;
} else {
tbp->b_flags |= flags | B_READ;
}
++b_save->bs_nchildren;
b_save->bs_children[i] = tbp;
for (j = 0; j < tbp->b_npages; j += 1) {
bp->b_pages[j + bp->b_npages] = tbp->b_pages[j];
}
bp->b_npages += tbp->b_npages;
bp->b_bcount += size;
bp->b_bufsize += size;
}
pmap_qenter((vm_offset_t) bp->b_data, (vm_page_t *)bp->b_pages, bp->b_npages);
return (bp);
}
/*
* Cleanup after a clustered read or write.
* This is complicated by the fact that any of the buffers might have
* extra memory (if there were no empty buffer headers at allocbuf time)
* that we will need to shift around.
*/
void
cluster_callback(bp)
struct buf *bp;
{
struct cluster_save *b_save;
struct buf **bpp, *tbp;
caddr_t cp;
int error = 0;
/*
* Must propogate errors to all the components.
*/
if (bp->b_flags & B_ERROR)
error = bp->b_error;
b_save = (struct cluster_save *) (bp->b_saveaddr);
pmap_qremove((vm_offset_t) bp->b_data, bp->b_npages);
/*
* Move memory from the large cluster buffer into the component
* buffers and mark IO as done on these.
*/
for (bpp = b_save->bs_children; b_save->bs_nchildren--; ++bpp) {
tbp = *bpp;
if (error) {
tbp->b_flags |= B_ERROR;
tbp->b_error = error;
}
biodone(tbp);
}
free(b_save, M_SEGMENT);
relpbuf(bp);
}
/*
* Do clustered write for FFS.
*
* Three cases:
* 1. Write is not sequential (write asynchronously)
* Write is sequential:
* 2. beginning of cluster - begin cluster
* 3. middle of a cluster - add to cluster
* 4. end of a cluster - asynchronously write cluster
*/
void
cluster_write(bp, filesize)
struct buf *bp;
u_quad_t filesize;
{
struct vnode *vp;
daddr_t lbn;
int maxclen, cursize;
int lblocksize;
vp = bp->b_vp;
lblocksize = vp->v_mount->mnt_stat.f_iosize;
lbn = bp->b_lblkno;
/* Initialize vnode to beginning of file. */
if (lbn == 0)
vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 ||
(bp->b_blkno != vp->v_lasta + btodb(lblocksize))) {
maxclen = MAXPHYS / lblocksize - 1;
if (vp->v_clen != 0) {
/*
* Next block is not sequential.
*
* If we are not writing at end of file, the process
* seeked to another point in the file since its last
* write, or we have reached our maximum cluster size,
* then push the previous cluster. Otherwise try
* reallocating to make it sequential.
*/
cursize = vp->v_lastw - vp->v_cstart + 1;
cluster_wbuild(vp, NULL, lblocksize,
vp->v_cstart, cursize, lbn);
}
/*
* Consider beginning a cluster. If at end of file, make
* cluster as large as possible, otherwise find size of
* existing cluster.
*/
if ((lbn + 1) * lblocksize != filesize &&
(VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen) ||
bp->b_blkno == -1)) {
bawrite(bp);
vp->v_clen = 0;
vp->v_lasta = bp->b_blkno;
vp->v_cstart = lbn + 1;
vp->v_lastw = lbn;
return;
}
vp->v_clen = maxclen;
if (maxclen == 0) { /* I/O not contiguous */
vp->v_cstart = lbn + 1;
bawrite(bp);
} else { /* Wait for rest of cluster */
vp->v_cstart = lbn;
bdwrite(bp);
}
} else if (lbn == vp->v_cstart + vp->v_clen) {
/*
* At end of cluster, write it out.
*/
cluster_wbuild(vp, bp, bp->b_bcount, vp->v_cstart,
vp->v_clen + 1, lbn);
vp->v_clen = 0;
vp->v_cstart = lbn + 1;
} else
/*
* In the middle of a cluster, so just delay the I/O for now.
*/
bdwrite(bp);
vp->v_lastw = lbn;
vp->v_lasta = bp->b_blkno;
}
/*
* This is an awful lot like cluster_rbuild...wish they could be combined.
* The last lbn argument is the current block on which I/O is being
* performed. Check to see that it doesn't fall in the middle of
* the current block (if last_bp == NULL).
*/
void
cluster_wbuild(vp, last_bp, size, start_lbn, len, lbn)
struct vnode *vp;
struct buf *last_bp;
long size;
daddr_t start_lbn;
int len;
daddr_t lbn;
{
struct cluster_save *b_save;
struct buf *bp, *tbp, *pb;
caddr_t cp;
int i, j, s;
#ifdef DIAGNOSTIC
if (size != vp->v_mount->mnt_stat.f_iosize)
panic("cluster_wbuild: size %d != filesize %d\n",
size, vp->v_mount->mnt_stat.f_iosize);
#endif
redo:
if( (lbn != -1) || (last_bp == 0)) {
while ((!(tbp = incore(vp, start_lbn)) || (tbp->b_flags & B_BUSY)
|| (start_lbn == lbn)) && len) {
++start_lbn;
--len;
}
pb = trypbuf();
/* Get more memory for current buffer */
if (len <= 1 || pb == 0) {
relpbuf(pb);
if (last_bp) {
bawrite(last_bp);
} else if (len) {
bp = getblk(vp, start_lbn, size, 0, 0);
bawrite(bp);
}
return;
}
tbp = getblk(vp, start_lbn, size, 0, 0);
} else {
tbp = last_bp;
if( tbp->b_flags & B_BUSY) {
printf("vfs_cluster: warning: buffer already busy\n");
}
tbp->b_flags |= B_BUSY;
last_bp = 0;
pb = trypbuf();
if( pb == 0) {
bawrite(tbp);
return;
}
}
if (!(tbp->b_flags & B_DELWRI)) {
relpbuf(pb);
++start_lbn;
--len;
brelse(tbp);
goto redo;
}
/*
* Extra memory in the buffer, punt on this buffer. XXX we could
* handle this in most cases, but we would have to push the extra
* memory down to after our max possible cluster size and then
* potentially pull it back up if the cluster was terminated
* prematurely--too much hassle.
*/
if (tbp->b_bcount != tbp->b_bufsize) {
relpbuf(pb);
++start_lbn;
--len;
bawrite(tbp);
goto redo;
}
bp = pb;
b_save = malloc(sizeof(struct buf *) * (len + 1) + sizeof(struct cluster_save),
M_SEGMENT, M_WAITOK);
b_save->bs_nchildren = 0;
b_save->bs_children = (struct buf **) (b_save + 1);
bp->b_saveaddr = b_save;
bp->b_bcount = 0;
bp->b_bufsize = 0;
bp->b_npages = 0;
if (tbp->b_flags & B_VMIO)
bp->b_flags |= B_VMIO;
bp->b_blkno = tbp->b_blkno;
bp->b_lblkno = tbp->b_lblkno;
bp->b_flags |= B_CALL | B_BUSY | B_CLUSTER;
bp->b_iodone = cluster_callback;
pbgetvp(vp, bp);
for (i = 0; i < len; ++i, ++start_lbn) {
if (i != 0) {
/*
* Block is not in core or the non-sequential block
* ending our cluster was part of the cluster (in
* which case we don't want to write it twice).
*/
if (!(tbp = incore(vp, start_lbn)) ||
(last_bp == NULL && start_lbn == lbn))
break;
if ((tbp->b_flags & (B_INVAL | B_CLUSTEROK)) != B_CLUSTEROK)
break;
if ((tbp->b_npages + bp->b_npages) > (MAXPHYS / PAGE_SIZE))
break;
/*
* Get the desired block buffer (unless it is the
* final sequential block whose buffer was passed in
* explictly as last_bp).
*/
if (last_bp == NULL || start_lbn != lbn) {
if( tbp->b_flags & B_BUSY)
break;
tbp = getblk(vp, start_lbn, size, 0, 0);
if (!(tbp->b_flags & B_DELWRI) ||
((tbp->b_flags & B_VMIO) != (bp->b_flags & B_VMIO))) {
brelse(tbp);
break;
}
} else
tbp = last_bp;
}
for (j = 0; j < tbp->b_npages; j += 1) {
bp->b_pages[j + bp->b_npages] = tbp->b_pages[j];
}
bp->b_npages += tbp->b_npages;
bp->b_bcount += size;
bp->b_bufsize += size;
tbp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI);
tbp->b_flags |= B_ASYNC;
s = splbio();
reassignbuf(tbp, tbp->b_vp); /* put on clean list */
++tbp->b_vp->v_numoutput;
splx(s);
b_save->bs_children[i] = tbp;
}
b_save->bs_nchildren = i;
pmap_qenter((vm_offset_t) bp->b_data, (vm_page_t *) bp->b_pages, bp->b_npages);
bawrite(bp);
if (i < len) {
len -= i;
goto redo;
}
}
/*
* Collect together all the buffers in a cluster.
* Plus add one additional buffer.
*/
struct cluster_save *
cluster_collectbufs(vp, last_bp)
struct vnode *vp;
struct buf *last_bp;
{
struct cluster_save *buflist;
daddr_t lbn;
int i, len;
len = vp->v_lastw - vp->v_cstart + 1;
buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
M_SEGMENT, M_WAITOK);
buflist->bs_nchildren = 0;
buflist->bs_children = (struct buf **) (buflist + 1);
for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++)
(void) bread(vp, lbn, last_bp->b_bcount, NOCRED,
&buflist->bs_children[i]);
buflist->bs_children[i] = last_bp;
buflist->bs_nchildren = i + 1;
return (buflist);
}