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Code Issues Releases Activity

The cache_enter(9) function shall not be called for doomed dvp.

Browse Source 
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
This commit is contained in:
Konstantin Belousov 2010-04-20 10:19:27 +00:00
parent 9d79ec20fb
commit 5673e3cb08
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=206894
3 changed files with 11 additions and 1 deletions
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2
sys/fs/pseudofs/pseudofs_vnops.c
View File

@ -542,7 +542,7 @@ pfs_lookup(struct vop_cachedlookup_args *va)
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:

2
sys/kern/vfs_cache.c
View File

@ -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;

8
sys/ufs/ufs/ufs_lookup.c
View File

@ -704,6 +704,14 @@ ufs_lookup_(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
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 {