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- A sanity check in unionfs verifies that lookups of '.' return the

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vnode of the parent.  However, this check should not be performed if
  the lookup failed.  This change should fix "union_lookup returning
  . not same as startdir" panics people were seeing.  The bug was
  introduced by an incomplete import of a NetBSD delta in rev 1.38.
- Move the aforementioned check out from DIAGNOSTIC.  Performance
  is the least of our unionfs worries.
- Minor reorganization.

PR:		53004
MFC after:	1 week
This commit is contained in:
David Schultz 2003-11-14 08:23:13 +00:00
parent 6f8b4fc03a
commit 95eac68fea
1 changed files with 21 additions and 27 deletions
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48
sys/fs/unionfs/union_vnops.c
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@ -583,37 +583,31 @@ union_lookup(ap)
((*ap->a_vpp) ? vrefcnt(*ap->a_vpp) : -99),
lowervp, uppervp));
/*
* dvp lock state, determine whether to relock dvp. dvp is expected
* to be locked on return if:
*
* - there was an error (except not EJUSTRETURN), or
* - we hit the last component and lockparent is true
*
* dvp_is_locked is the current state of the dvp lock, not counting
* the possibility that *ap->a_vpp == dvp (in which case it is locked
* anyway). Note that *ap->a_vpp == dvp only if no error occured.
*/
if (error == 0 || error == EJUSTRETURN) {
/*
* dvp lock state, determine whether to relock dvp.
* We are expected to unlock dvp unless:
*
* - there was an error (other than EJUSTRETURN), or
* - we hit the last component and lockparent is true
*/
if (*ap->a_vpp != dvp) {
if (!lockparent || (cnp->cn_flags & ISLASTCN) == 0)
VOP_UNLOCK(dvp, 0, td);
}
if (*ap->a_vpp != dvp) {
if ((error == 0 || error == EJUSTRETURN) &&
(!lockparent || (cnp->cn_flags & ISLASTCN) == 0)) {
VOP_UNLOCK(dvp, 0, td);
if (cnp->cn_namelen == 1 &&
cnp->cn_nameptr[0] == '.' &&
*ap->a_vpp != dvp) {
#ifdef DIAGNOSTIC
vprint("union_lookup: vp", *ap->a_vpp);
vprint("union_lookup: dvp", dvp);
#endif
panic("union_lookup returning . (%p) != startdir (%p)",
*ap->a_vpp, dvp);
}
}
/*
* Diagnostics
*/
#ifdef DIAGNOSTIC
if (cnp->cn_namelen == 1 &&
cnp->cn_nameptr[0] == '.' &&
*ap->a_vpp != dvp) {
panic("union_lookup returning . (%p) not same as startdir (%p)", ap->a_vpp, dvp);
}
#endif
return (error);
}