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

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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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 {