Author: kib
Date: Tue Apr 20 10:19:27 2010
New Revision: 206894
URL: http://svn.freebsd.org/changeset/base/206894
Log:
The cache_enter(9) function shall not be called for doomed dvp.
Assert this.
In the reported panic, vdestroy() fired the assertion "vp has namecache
for ..", because pseudofs may end up doing cache_enter() with reclaimed
dvp, after dotdot lookup temporary unlocked dvp.
Similar problem exists in ufs_lookup() for "." lookup, when vnode
lock needs to be upgraded.
Verify that dvp is not reclaimed before calling cache_enter().
Reported and tested by: pho
Reviewed by: kan
MFC after: 2 weeks
Modified:
head/sys/fs/pseudofs/pseudofs_vnops.c
head/sys/kern/vfs_cache.c
head/sys/ufs/ufs/ufs_lookup.c
Modified: head/sys/fs/pseudofs/pseudofs_vnops.c
==============================================================================
--- head/sys/fs/pseudofs/pseudofs_vnops.c Tue Apr 20 10:16:44 2010
(r206893)
+++ head/sys/fs/pseudofs/pseudofs_vnops.c Tue Apr 20 10:19:27 2010
(r206894)
@@ -542,7 +542,7 @@ pfs_lookup(struct vop_cachedlookup_args
if (cnp->cn_flags & ISDOTDOT)
vn_lock(vn, LK_EXCLUSIVE|LK_RETRY);
- if (cnp->cn_flags & MAKEENTRY)
+ if (cnp->cn_flags & MAKEENTRY && !(vn->v_iflag & VI_DOOMED))
cache_enter(vn, *vpp, cnp);
PFS_RETURN (0);
failed:
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Tue Apr 20 10:16:44 2010 (r206893)
+++ head/sys/kern/vfs_cache.c Tue Apr 20 10:19:27 2010 (r206894)
@@ -611,6 +611,8 @@ cache_enter(dvp, vp, cnp)
CTR3(KTR_VFS, "cache_enter(%p, %p, %s)", dvp, vp, cnp->cn_nameptr);
VNASSERT(vp == NULL || (vp->v_iflag & VI_DOOMED) == 0, vp,
("cache_enter: Adding a doomed vnode"));
+ VNASSERT(dvp == NULL || (dvp->v_iflag & VI_DOOMED) == 0, dvp,
+ ("cache_enter: Doomed vnode used as src"));
if (!doingcache)
return;
Modified: head/sys/ufs/ufs/ufs_lookup.c
==============================================================================
--- head/sys/ufs/ufs/ufs_lookup.c Tue Apr 20 10:16:44 2010
(r206893)
+++ head/sys/ufs/ufs/ufs_lookup.c Tue Apr 20 10:19:27 2010
(r206894)
@@ -704,6 +704,14 @@ found:
vn_lock(vdp, LK_UPGRADE | LK_RETRY);
else /* if (ltype == LK_SHARED) */
vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
+ /*
+ * Relock for the "." case may left us with
+ * reclaimed vnode.
+ */
+ if (vdp->v_iflag & VI_DOOMED) {
+ vrele(vdp);
+ return (ENOENT);
+ }
}
*vpp = vdp;
} else {
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