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Cannot release vnode underlying the nullfs vnode in null_inactive

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as it leaves the nullfs vnode allocated, but with no identity. The
effect is that a null mount can slowly accumulate all the vnodes
in the system, reclaiming them only when it is unmounted. Thus
the null_inactive state instead accelerates the release of the
null vnode by calling vrecycle which will in turn call the
null_reclaim operator. The null_reclaim routine then does the
freeing actions previosuly (incorrectly) done in null_inactive.
This commit is contained in:
Kirk McKusick 2002-03-18 05:39:04 +00:00
parent e5fa3ee654
commit b70428b2f0
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=92540
1 changed files with 26 additions and 19 deletions
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45
sys/fs/nullfs/null_vnops.c
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@ -711,27 +711,13 @@ null_inactive(ap)
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct thread *td = ap->a_td;
struct null_node *xp = VTONULL(vp);
struct vnode *lowervp = xp->null_lowervp;
lockmgr(&null_hashlock, LK_EXCLUSIVE, NULL, td);
LIST_REMOVE(xp, null_hash);
lockmgr(&null_hashlock, LK_RELEASE, NULL, td);
xp->null_lowervp = NULLVP;
if (vp->v_vnlock != NULL) {
vp->v_vnlock = &vp->v_lock; /* we no longer share the lock */
} else
VOP_UNLOCK(vp, LK_THISLAYER, td);
vput(lowervp);
/*
* Now it is safe to drop references to the lower vnode.
* VOP_INACTIVE() will be called by vrele() if necessary.
* If this is the last reference, then free up the vnode
* so as not to tie up the lower vnodes.
*/
vrele (lowervp);
if (vp->v_usecount == 0)
vrecycle(vp, NULL, ap->a_td);
return (0);
}
@ -746,9 +732,30 @@ null_reclaim(ap)
struct thread *a_td;
} */ *ap;
{
struct thread *td = ap->a_td;
struct vnode *vp = ap->a_vp;
void *vdata = vp->v_data;
struct null_node *xp = VTONULL(vp);
struct vnode *lowervp = xp->null_lowervp;
void *vdata;
lockmgr(&null_hashlock, LK_EXCLUSIVE, NULL, td);
LIST_REMOVE(xp, null_hash);
lockmgr(&null_hashlock, LK_RELEASE, NULL, td);
xp->null_lowervp = NULLVP;
if (vp->v_vnlock != NULL) {
vp->v_vnlock = &vp->v_lock; /* we no longer share the lock */
} else
VOP_UNLOCK(vp, LK_THISLAYER, td);
/*
* Now it is safe to drop references to the lower vnode.
* VOP_INACTIVE() will be called by vrele() if necessary.
*/
vput(lowervp);
vrele (lowervp);
vdata = vp->v_data;
vp->v_data = NULL;
FREE(vdata, M_NULLFSNODE);