Re: [libvirt] [virt-tools-list] [PATCH] virtinst: refresh pools status before fetch_pools

On 11.12.2014 03:27, Chun Yan Liu wrote: > > >>>>On 12/5/2014 at 09:54 PM, in message <5481B907.4040507(a)redhat.com&gt;, Cole >Robinson <crobinso(a)redhat.com&gt; wrote: >>On 12/05/2014 03:40 AM, Chunyan Liu wrote: >>> <snip/> >>>+ # Refresh pools before poll_helper. For those >>>+ # 'active' but target path not exist (or other reasons >>>+ # causing the pool not working), but libvirtd not >>>+ # refresh the status, this will make it refreshed >>>+ # and mark that pool as 'inactive'. >>>+ objs = backend.listAllStoragePools() >>>+ for obj in objs: >>>+ try: >>>+ obj.refresh(0) >>>+ except Exception, e: >>>+ pass >>>+ >>> return _new_poll_helper(origmap, name, >>> backend.listAllStoragePools, build_func) >>> else: >>> >> >>This is a very heavy hammer, refresh is a potentially long running operation >> >>so this could cause decent slowdown in some scenarios. >> >>IMO this is essentially a libvirt bug, for pools with target directories >>(dir, >>fs, netfs), libvirt should be periodically checking the directory ctime and >>doing the pool refresh for us. And if the target has disappeared, it shuts >>down the pool (like shutting down a VM if it crashes). Makes sense to me. Although, refreshing a dir can again be a long running job (consider dir pool built in a NFS mount). I wonder if we should use {d,i,fa}notify or if checking ctime is enough.