From ec4f9fb0ee96e85040eae669f59d7bd9911d37f8 Mon Sep 17 00:00:00 2001
From: David Greenman <dg@FreeBSD.org>
Date: Sun, 16 Apr 1995 03:11:28 +0000
Subject: [PATCH] Fixed a few bugs in vm_object_page_clean, mostly related to
not syncing pages that are in FS buffers. This fixes the (believed to already
have been fixed) problem with msync() not doing it's job...in other words,
the stuff that Andrew has continuously been complaining about.
Submitted by: John Dyson, w/minor changes by me.
---
sys/vm/vm_object.c | 32 +++++++++++++++++++++-----------
1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index ba5c985907bf..66acf44b26fd 100644
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -61,7 +61,7 @@
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
- * $Id: vm_object.c,v 1.40 1995/03/25 08:42:14 davidg Exp $
+ * $Id: vm_object.c,v 1.41 1995/04/09 06:03:49 davidg Exp $
*/
/*
@@ -470,6 +470,7 @@ _vm_object_page_clean(object, start, end, syncio)
int pass;
int pgcount, s;
int allclean;
+ int entireobj;
if (object->pager == NULL || (object->flags & OBJ_WRITEABLE) == 0)
return;
@@ -479,8 +480,6 @@ _vm_object_page_clean(object, start, end, syncio)
end = round_page(end);
}
- object->flags &= ~OBJ_WRITEABLE;
-
pass = 0;
startover:
tstart = start;
@@ -489,6 +488,11 @@ startover:
} else {
tend = end;
}
+ entireobj = 0;
+ if (tstart == 0 && tend == object->size) {
+ object->flags &= ~OBJ_WRITEABLE;
+ entireobj = 1;
+ }
/*
* Wait until potential collapse operation is complete
*/
@@ -504,7 +508,7 @@ startover:
pgcount = object->resident_page_count;
if (pass == 0 &&
- (pgcount < 128 || pgcount > (object->size / (8 * PAGE_SIZE)))) {
+ (pgcount < 128 || pgcount > (object->size / (8 * PAGE_SIZE)))) {
allclean = 1;
for(; pgcount && (tstart < tend); tstart += PAGE_SIZE) {
p = vm_page_lookup(object, tstart);
@@ -515,8 +519,10 @@ startover:
TAILQ_REMOVE(&object->memq, p, listq);
TAILQ_INSERT_TAIL(&object->memq, p, listq);
splx(s);
- if ((p->flags & (PG_BUSY|PG_CACHE)) || p->busy || p->valid == 0 ||
- p->bmapped) {
+ if (entireobj)
+ vm_page_protect(p, VM_PROT_READ);
+ if ((p->flags & (PG_BUSY|PG_CACHE)) || p->busy ||
+ p->valid == 0) {
continue;
}
vm_page_test_dirty(p);
@@ -533,7 +539,6 @@ startover:
pass = 1;
goto startover;
}
- object->flags &= ~OBJ_WRITEABLE;
return;
}
@@ -544,8 +549,11 @@ startover:
goto donext;
}
- if (p->offset >= tstart && p->offset < tend) {
- if (p->valid == 0 || p->bmapped) {
+ if (entireobj || (p->offset >= tstart && p->offset < tend)) {
+ if (entireobj)
+ vm_page_protect(p, VM_PROT_READ);
+
+ if (p->valid == 0) {
goto donext;
}
@@ -580,9 +588,11 @@ startover:
TAILQ_INSERT_TAIL(&object->memq, p, listq);
pgcount--;
}
- if ((!allclean && (pass == 0)) || (object->flags & OBJ_WRITEABLE)) {
+ if ((!allclean && (pass == 0)) ||
+ (entireobj && (object->flags & OBJ_WRITEABLE))) {
pass = 1;
- object->flags &= ~OBJ_WRITEABLE;
+ if (entireobj)
+ object->flags &= ~OBJ_WRITEABLE;
goto startover;
}
return;