Remove a soft-update hook that was accidentally added to the READ path.

also add some comments, and a couple of very minor cosmetic changes.
This commit is contained in:
Julian Elischer 1998-03-16 18:39:41 +00:00
parent 38b22f2b1f
commit c2a94b7a3c

View File

@ -33,7 +33,7 @@
* SUCH DAMAGE.
*
* @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94
* $Id: vfs_cluster.c,v 1.57 1998/03/08 09:57:09 julian Exp $
* $Id: vfs_cluster.c,v 1.58 1998/03/16 01:55:24 dyson Exp $
*/
#include "opt_debug_cluster.h"
@ -407,9 +407,6 @@ cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp)
break;
}
}
/* check for latent dependencies to be handled */
if ((LIST_FIRST(&tbp->b_dep)) != NULL && bioops.io_start)
(*bioops.io_start)(tbp);
TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
tbp, b_cluster.cluster_entry);
for (j = 0; j < tbp->b_npages; j += 1) {
@ -641,7 +638,7 @@ cluster_wbuild(vp, size, start_lbn, len)
while (len > 0) {
s = splbio();
if (((tbp = gbincore(vp, start_lbn)) == NULL) ||
((tbp->b_flags & (B_INVAL|B_BUSY|B_DELWRI)) != B_DELWRI)) {
((tbp->b_flags & (B_INVAL|B_BUSY|B_DELWRI)) != B_DELWRI)) {
++start_lbn;
--len;
splx(s);
@ -660,18 +657,10 @@ cluster_wbuild(vp, size, start_lbn, len)
* prematurely--too much hassle.
*/
if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) ||
(tbp->b_bcount != tbp->b_bufsize) ||
(tbp->b_bcount != size) ||
len == 1) {
totalwritten += tbp->b_bufsize;
bawrite(tbp);
++start_lbn;
--len;
continue;
}
bp = trypbuf();
if (bp == NULL) {
(tbp->b_bcount != tbp->b_bufsize) ||
(tbp->b_bcount != size) ||
(len == 1) ||
((bp = trypbuf()) == NULL)) {
totalwritten += tbp->b_bufsize;
bawrite(tbp);
++start_lbn;
@ -679,6 +668,10 @@ cluster_wbuild(vp, size, start_lbn, len)
continue;
}
/*
* We got a pbuf to make the cluster in.
* so initialise it.
*/
TAILQ_INIT(&bp->b_cluster.cluster_head);
bp->b_bcount = 0;
bp->b_bufsize = 0;
@ -691,20 +684,38 @@ cluster_wbuild(vp, size, start_lbn, len)
bp->b_blkno = tbp->b_blkno;
bp->b_lblkno = tbp->b_lblkno;
bp->b_offset = tbp->b_offset;
(vm_offset_t) bp->b_data |= ((vm_offset_t) tbp->b_data) & PAGE_MASK;
(vm_offset_t) bp->b_data |=
((vm_offset_t) tbp->b_data) & PAGE_MASK;
bp->b_flags |= B_CALL | B_BUSY | B_CLUSTER |
(tbp->b_flags & (B_VMIO|B_NEEDCOMMIT));
(tbp->b_flags & (B_VMIO|B_NEEDCOMMIT));
bp->b_iodone = cluster_callback;
pbgetvp(vp, bp);
/*
* From this location in the file, scan forward to see
* if there are buffers with adjacent data that need to
* be written as well.
*/
for (i = 0; i < len; ++i, ++start_lbn) {
if (i != 0) {
if (i != 0) { /* If not the first buffer */
s = splbio();
/*
* If the adjacent data is not even in core it
* can't need to be written.
*/
if ((tbp = gbincore(vp, start_lbn)) == NULL) {
splx(s);
break;
}
if ((tbp->b_flags & (B_VMIO|B_CLUSTEROK|B_INVAL|B_BUSY|B_DELWRI|B_NEEDCOMMIT)) != (B_DELWRI|B_CLUSTEROK|(bp->b_flags & (B_VMIO|B_NEEDCOMMIT)))) {
/*
* If it IS in core, but has different
* characteristics, don't cluster with it.
*/
if ((tbp->b_flags &
(B_VMIO|B_CLUSTEROK|B_INVAL|B_BUSY|
B_DELWRI|B_NEEDCOMMIT))
!= (B_DELWRI|B_CLUSTEROK|
(bp->b_flags & (B_VMIO|B_NEEDCOMMIT)))) {
splx(s);
break;
}
@ -714,25 +725,41 @@ cluster_wbuild(vp, size, start_lbn, len)
break;
}
/*
* Check that the combined cluster
* would make sense with regard to pages
* and would not be too large
*/
if ((tbp->b_bcount != size) ||
((bp->b_blkno + dbsize * i) != tbp->b_blkno) ||
((tbp->b_npages + bp->b_npages) > (vp->v_maxio / PAGE_SIZE))) {
((bp->b_blkno + (dbsize * i)) !=
(tbp->b_blkno)) ||
((tbp->b_npages + bp->b_npages) >
(vp->v_maxio / PAGE_SIZE))) {
splx(s);
break;
}
/*
* Ok, it's passed all the tests,
* so remove it from the free list
* and mark it busy. We will use it.
*/
bremfree(tbp);
tbp->b_flags |= B_BUSY;
tbp->b_flags &= ~B_DONE;
splx(s);
}
} /* end of code for non-first buffers only */
/* check for latent dependencies to be handled */
if ((LIST_FIRST(&tbp->b_dep)) != NULL &&
bioops.io_start)
(*bioops.io_start)(tbp);
/*
* If the IO is via the VM then we do some
* special VM hackery. (yuck)
*/
if (tbp->b_flags & B_VMIO) {
vm_page_t m;
if (i != 0) {
if (i != 0) { /* if not first buffer */
for (j = 0; j < tbp->b_npages; j += 1) {
m = tbp->b_pages[j];
if (m->flags & PG_BUSY)
@ -745,7 +772,7 @@ cluster_wbuild(vp, size, start_lbn, len)
++m->busy;
++m->object->paging_in_progress;
if ((bp->b_npages == 0) ||
(bp->b_pages[bp->b_npages - 1] != m)) {
(bp->b_pages[bp->b_npages - 1] != m)) {
bp->b_pages[bp->b_npages] = m;
bp->b_npages++;
}