Re: [libvirt] [PATCH] storage: Refresh pool after creating volume

On Mon, Jun 03, 2013 at 11:47:10PM +0800, Osier Yang wrote: > On 01/06/13 16:05, Martin Kletzander wrote: > >commit 416247880399f88ec382a16c7cebc5460d6b67ad > >Author: Martin Kletzander <mkletzan(a)redhat.com&gt; > >Date: Fri May 31 14:25:48 2013 +0200 > > > > test > > > >diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c > >index 1a85afc..a119fc4 100644 > >--- a/src/storage/storage_backend_fs.c > >+++ b/src/storage/storage_backend_fs.c > >@@ -1,7 +1,7 @@ > > /* > > * storage_backend_fs.c: storage backend for FS and directory handling > > * > >- * Copyright (C) 2007-2012 Red Hat, Inc. > >+ * Copyright (C) 2007-2013 Red Hat, Inc. > > * Copyright (C) 2007-2008 Daniel P. Berrange > > * > > * This library is free software; you can redistribute it and/or > >@@ -797,6 +797,27 @@ error: > > } > > > > > >+static int > >+virStorageBackendStatVFS(virStoragePoolDefPtr def) > >+{ > >+ struct statvfs sb; > >+ > >+ if (statvfs(def->target.path, &sb) < 0) { > >+ virReportSystemError(errno, > >+ _("cannot statvfs path '%s'"), > >+ def->target.path); > >+ return -1; > >+ } > >+ def->capacity = ((unsigned long long)sb.f_frsize * > >+ (unsigned long long)sb.f_blocks); > >+ def->available = ((unsigned long long)sb.f_bfree * > >+ (unsigned long long)sb.f_frsize); > >+ def->allocation = def->capacity - def->available; > >+ > >+ return 0; > >+} > >+ > > Though this is only for fs backend, I could see your thought (only > refresh the > pool's capacity, available, and allocation, without collecting the > volumes), right? > This makes sense for fs backend indeed, but not for some of the other > backends, for instance, scsi backend pool, it populates the pool's capacity, > available, allocation while scanning the LUNs... This would also mean that we do heaps of pool refreshes when creating lots of volumes which can be an expensive operation. Shouldn't we rather only update the information from the information we have from the newly created volume?