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Incorporated 4.4-lite vnode_pager_uncache() and vnode_pager_umount()

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routines (and merged local changes). The changed vnode_pager_uncache
gets rids of the bogosity that you can call the routine without
having the vnode locked. The changed vnode_pager_umount properly locks
the vnode before calling vnode_pager_uncache.
This commit is contained in:
David Greenman 1995-03-19 12:36:10 +00:00
parent 0f52ba3503
commit c01a9b8ca0
1 changed files with 22 additions and 20 deletions
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42
sys/vm/vnode_pager.c
View File

@ -37,7 +37,7 @@
* SUCH DAMAGE.
*
* from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
* $Id: vnode_pager.c,v 1.29 1995/03/12 07:56:06 davidg Exp $
* $Id: vnode_pager.c,v 1.30 1995/03/16 18:17:34 bde Exp $
*/
/*
@ -414,33 +414,36 @@ vnode_pager_umount(mp)
register vm_pager_t pager, npager;
struct vnode *vp;
pager = vnode_pager_list.tqh_first;
while (pager) {
for (pager = vnode_pager_list.tqh_first; pager != NULL; pager = npager) {
/*
* Save the next pointer now since uncaching may terminate the
* object and render pager invalid
*/
vp = ((vn_pager_t) pager->pg_data)->vnp_vp;
npager = pager->pg_list.tqe_next;
if (mp == (struct mount *) 0 || vp->v_mount == mp)
vp = ((vn_pager_t) pager->pg_data)->vnp_vp;
if (mp == (struct mount *) 0 || vp->v_mount == mp) {
VOP_LOCK(vp);
(void) vnode_pager_uncache(vp);
pager = npager;
VOP_UNLOCK(vp);
}
}
}
/*
* Remove vnode associated object from the object cache.
* This routine must be called with the vnode locked.
*
* Note: this routine may be invoked as a result of a pager put
* operation (possibly at object termination time), so we must be careful.
* XXX unlock the vnode.
* We must do this since uncaching the object may result in its
* destruction which may initiate paging activity which may necessitate
* re-locking the vnode.
*/
boolean_t
vnode_pager_uncache(vp)
register struct vnode *vp;
{
register vm_object_t object;
boolean_t uncached, locked;
boolean_t uncached;
vm_pager_t pager;
/*
@ -454,15 +457,14 @@ vnode_pager_uncache(vp)
if (pager == NULL)
return (TRUE);
/*
* Unlock the vnode if it is currently locked. We do this since
* uncaching the object may result in its destruction which may
* initiate paging activity which may necessitate locking the vnode.
*/
locked = VOP_ISLOCKED(vp);
if (locked)
VOP_UNLOCK(vp);
#ifdef DEBUG
if (!VOP_ISLOCKED(vp)) {
extern int (**nfsv2_vnodeop_p)();
if (vp->v_op != nfsv2_vnodeop_p)
panic("vnode_pager_uncache: vnode not locked!");
}
#endif
/*
* Must use vm_object_lookup() as it actually removes the object from
* the cache list.
@ -470,11 +472,11 @@ vnode_pager_uncache(vp)
object = vm_object_lookup(pager);
if (object) {
uncached = (object->ref_count <= 1);
VOP_UNLOCK(vp);
pager_cache(object, FALSE);
VOP_LOCK(vp);
} else
uncached = TRUE;
if (locked)
VOP_LOCK(vp);
return (uncached);
}