> On Mar 24, 2016, at 21:55, Ilya Dryomov <idryomov@xxxxxxxxx> wrote: > > On Thu, Mar 24, 2016 at 2:18 PM, Yan, Zheng <zyan@xxxxxxxxxx> wrote: >> >>> On Mar 24, 2016, at 18:26, Ilya Dryomov <idryomov@xxxxxxxxx> wrote: > > [ snip ] > >>> TBH I still can't wrap my head around lockless layout/namespace pointer >>> updates and how that can ever work reliably… >> >> see Documentation/RCU/rcuref.txt. How RCU is used in my code is similar to the second example. > > It's the higher-level cephfs code and installing new namespaces in the > middle of whatever else that might be going on that I'm worried about. > See my other mail, I'd like to hear what exactly is being achieved with > this approach and have you considered reusing i_ceph_lock (or others, > of which there are plenty). Updating namespace pointer is protected by i_ceph_lock, For read access of the namespace, using i_ceph_lock does not provide any extra guarantee. This approach provides lockless access of namespace, it’s convenient for functions that do not know i_ceph_lock. Regards Yan, Zheng > Thanks, > > Ilya -- 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
