On 08/17/2012 11:54 PM, Sage Weil wrote: > Hi Yan, > > On Fri, 17 Aug 2012, Yan, Zheng wrote: >> From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx> >> >> req->r_locked_dir is NULL if the request was created by >> open_root_dentry(). ceph_fill_trace() lacks check for this case. >> It causes oops when mounting cephfs with non-existing path. > > This is actually an MDS bug. The problem is that the client is issuing a > GETATTR request and isn't prepared to handle a dentry in the reply, but > the MDS sees that there is a relative path in the request and behaves like > this is a lookup. We were distinguishing correctly between the two cases > on success, but not on error. I've pushed branch bug-2969 to ceph.git > which fixes this for me. Can you please test and verify it resolves > the problem? It does resolve the problem. > > We may want to have a check like the below, but it should probably be > accompanied by a pr_warning or WARN_ON() since it is a protocol error. > Generally speaking, the client isn't allowed to ignore state the MDS has > issued it (in this case, caps on the directory inode; lower down in > fill_trace possibly a dentry lease) without messing up the protocol. > Thank you for your explanation. Yan, Zheng -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
