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Don't try to cluster busy buffers.

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Submitted by:	John Dyson
This commit is contained in:
dg 1995-03-02 19:36:50 +00:00
parent 3bc88398f8
commit 31019b7202
1 changed files with 36 additions and 17 deletions
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53
sys/kern/vfs_cluster.c
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@ -33,7 +33,7 @@
* SUCH DAMAGE.
*
* @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94
* $Id: vfs_cluster.c,v 1.9 1995/01/24 10:00:46 davidg Exp $
* $Id: vfs_cluster.c,v 1.10 1995/02/22 09:39:20 davidg Exp $
*/
#include <sys/param.h>
@ -502,24 +502,40 @@ cluster_wbuild(vp, last_bp, size, start_lbn, len, lbn)
size, vp->v_mount->mnt_stat.f_iosize);
#endif
redo:
while ((!incore(vp, start_lbn) || start_lbn == lbn) && len) {
++start_lbn;
--len;
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 = (struct buf *) 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 = (struct buf *) trypbuf();
if( pb == 0) {
bawrite(tbp);
return;
}
}
pb = (struct buf *) 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);
if (!(tbp->b_flags & B_DELWRI)) {
relpbuf(pb);
++start_lbn;
@ -574,6 +590,9 @@ redo:
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