Re: [libvirt] [PATCH 3/8] storage: Prior to creating a volume, refresh the pool

On 10/05/2015 07:28 AM, Michal Privoznik wrote: > On 02.10.2015 15:41, John Ferlan wrote: >> https://bugzilla.redhat.com/show_bug.cgi?id=1233003 >> >> Although perhaps bordering on a don't do that type scenario, if >> someone creates a volume in a pool outside of libvirt, then uses that >> same name to create a volume in the pool via libvirt, then the creation >> will fail and in some cases cause the same name volume to be deleted. >> >> This patch will refresh the pool just prior to checking whether the >> named volume exists prior to creating the volume in the pool. While >> it's still possible to have a timing window to create a file after the >> check - at least we tried. At that point, someone is being malicious. >> >> Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; >> --- >> src/storage/storage_driver.c | 9 +++++++++ >> 1 file changed, 9 insertions(+) >> >> diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c >> index 7aaa060..ddf4405 100644 >> --- a/src/storage/storage_driver.c >> +++ b/src/storage/storage_driver.c >> @@ -1796,6 +1796,15 @@ storageVolCreateXML(virStoragePoolPtr obj, >> if (virStorageVolCreateXMLEnsureACL(obj->conn, pool->def, voldef) < 0) >> goto cleanup; >> >> + /* While not perfect, refresh the list of volumes in the pool and >> + * then check that the incoming name isn't already in the pool. >> + */ >> + if (backend->refreshPool) { >> + virStoragePoolObjClearVols(pool); >> + if (backend->refreshPool(obj->conn, pool) < 0) >> + goto cleanup; >> + } >> + >> if (virStorageVolDefFindByName(pool, voldef->name)) { >> virReportError(VIR_ERR_STORAGE_VOL_EXIST, >> _("'%s'"), voldef->name); >> >

> Okay, this makes sense. Not only from the POV you are presenting, but I'd expect my pool to be refreshed after I create new volume in it. >

> And I think we have a way to eliminate even the little window - just track if we successfully built the volume or not. Something among these lines: >