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Do not leak the NULLV_NOUNLOCK flag from the nullfs_unlink_lowervp(),

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for the case when the nullfs vnode is not reclaimed.  Otherwise, later
reclamation would not unlock the lower vnode.

Reported by:	antoine
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2013-05-21 11:31:56 +00:00
parent 4f493a25f4
commit 74c7ff1a0e
1 changed files with 19 additions and 7 deletions
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26
sys/fs/nullfs/null_vfsops.c
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@ -409,16 +409,28 @@ nullfs_unlink_lowervp(struct mount *mp, struct vnode *lowervp)
vhold(vp); vhold(vp);
vunref(vp); vunref(vp);
/*
* If vunref() dropped the last use reference on the nullfs
* vnode, it must be reclaimed, and its lock was split from
* the lower vnode lock. Need to do extra unlock before
* allowing the final vdrop() to free the vnode.
*/
if (vp->v_usecount == 0) { if (vp->v_usecount == 0) {
/*
* If vunref() dropped the last use reference on the
* nullfs vnode, it must be reclaimed, and its lock
* was split from the lower vnode lock. Need to do
* extra unlock before allowing the final vdrop() to
* free the vnode.
*/
KASSERT((vp->v_iflag & VI_DOOMED) != 0, KASSERT((vp->v_iflag & VI_DOOMED) != 0,
("not reclaimed %p", vp)); ("not reclaimed nullfs vnode %p", vp));
VOP_UNLOCK(vp, 0); VOP_UNLOCK(vp, 0);
} else {
/*
* Otherwise, the nullfs vnode still shares the lock
* with the lower vnode, and must not be unlocked.
* Also clear the NULLV_NOUNLOCK, the flag is not
* relevant for future reclamations.
*/
ASSERT_VOP_ELOCKED(vp, "unlink_lowervp");
KASSERT((vp->v_iflag & VI_DOOMED) == 0,
("reclaimed nullfs vnode %p", vp));
xp->null_flags &= ~NULLV_NOUNLOCK;
} }
vdrop(vp); vdrop(vp);
} }