On Wed, Nov 19, 2008 at 11:41:43AM -0500, David Lively wrote: I'm not sure whether this is actually required. We're using gnulib for socket stuff, and that wraps the Winsock socket() call so that it returns a real file descriptor rather than a socket handle. It does this calling _open_osfhandle which appears to be declared to accept a 'long' and return an 'int' - at least in MinGW headers. MinGW doesn't implement Win64 though, so its possible the header isn't quite right. If you have a Win64 box available, could you post what you see as the declarations for _open_osfhandle _get_osfhandle Regards, Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|

On Wed, Nov 19, 2008 at 01:28:23PM -0500, David Lively wrote: No, the gnulib stuff is internal only - we don't force any apps to also use gnulib. It does however mean we should document that the 'fd' arg of the the virEventAddHandle callback is an file handle, and not a socket handle on Win32, so apps are clear on what to expect. If they're not using gnulib themselves, they can trivially convert back to a true socket handle if desired. Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|

On Wed, Nov 19, 2008 at 01:50:09PM -0500, Shahar Frank wrote: libvirt does not yet have support for SCSI FiberChannel, but it will be added following this forthcoming release. libvirt's storage model has two core concepts, a 'pool' object, which contains multiple 'volume' objects. There are different types of pool for each type of storage, so we intend to add a 'scsi' storage pool. The way it will work is that each SCSI HBA will be seen as its own storage pool. The LUNs for a HBA will then be volumes within the pool. So for enumerateLuns, a combination of API calls would be relevant. - virConnectFindStoragePoolSources() with a type='scsi' will discover all available HBAs, and return XML describing them. For each HBA you care about, you would define a storage pool and active it using - virStoragePoolDefineXML() - virStoragePoolStart() Then, for each storage pool you can get the list of LUNs by asking for its volumes with - virStoragePoolListVolumes() This will work in exactly the same way as for SCIS, except that instead of calling virConnectFindStoragePoolSources with type='scsi', you'd call it with type='iscsi'. You'd also need to give a 'srcSpec' XML document with details of the host providing the iSCSI server. With this libvirt will connect to the iSCSI server, and ask it for all its exported iSCSI targets. The returned XML will provide details on each target. For each target you wish to use, then you call virStoragePoolDefinXML and virStoragePoolStart(), as before. Once you have a virStorageVolPtr object, you can use the API virStorageVolGetInfo this gives you logical capacity, and actual allocation - allocation may be less than capacity if querying a file based volume like a sparse file, or qcow2. To get a persistent name, akin to a UUID, you can use the API virStorageVolGetKey() for SCSI LUNS, the volume key will be based off the UUID avialable. This is very similar to the other enumerate methods. You'd call virConnectFindStoragePoolSources() with type='logical' this gives you back XML describing all available volume groups on a machine. For each volume group you want to use, you can then define a storage pool, and query volumes within it. libvirt can take care of that when needed, which is why we have a two step process for accessing a storage pool - virStoragePoolDefineXML() will write out a persistent configuratipon file with details of the pool. - virStoragePoolCreate() will actually login to the iSCSI target, or activate the LVM volume group, or equivalent operations needed for the type of storage being accessed. NB 'Create' is probably better thought of as 'Start' You can later call virStoragePoolDestroy() to logout if desired. If you want login to happen automatically when the machine boots you can call virStoragePoolSetAutostart() to turn on the autostart flag. Authentication is an open, unresolved issue & welcome suggestions for how to deal with this. Our original thoughts were to just embed the iSCSI username/password in the XML configuration file for the storage pool, but we've not implemented this in the backend yet. This is accomplished with a combination of two methods. First you define the configuration for the pool, which requires giving the volume group name, and list of devices to become PVs in the VG. This is done with virStoragePoolDefineXML(). Then you actually format the PVs & construct the VG by invoking the virStoragePoolBuild() method. Once this is done, the virStoragePoolCreate() method will activate the VG. Given a existing virStoragePoolPtr object, you can blow away the entire volume group using the API virStoragePoolDelete Each NFS mount is modelled as a storage pool. So as before, you'd create a XML document providing the configuration for server, remotePath, localPath, and then invoke virStoragePoolDefineXML() Then you can use virStoragePoolCreate() to mount the NFS server. Once done, you can use virStoragePoolListVolumes() to query files within the mount. The virStoragePoolDestory() method will unmount the NFS volume. If you wish to also remove the persistent libvirt config file for the pool, then also issue virStoragePoolUndefine Most objects in the libvirt API have two modes of setup, one which is persistent, and one which is transient. The examples I've given earlier all describe persistent use. The general pattern is - virStoragePoolDefineXML() writes the persistent config - virStoragePoolCreate() activates the backend from persistent config - virStoragePoolDestroy() de-activates the backend - virStoragePoolUndefine() deletes the persistent config If you instead prefer to use transient objects, then you can do - virStoragePoolCreateXML() - activates a backend directly from XML - virStoragePoolDestroy() - de-actives the backend With this style, no persistent configuration file is written out to disk, so once destroyed, libvirt looses all knowledge of it. If libvirtd is restarted, all information about transient objects is lost. Persistent objects will be identified when libvirtd is started again. For persistent objects you can also set a autostart flag, so that libvirt will immediately activate them, if not already running. The XML description for a virStoragePoolPtr object pointing to a VG, will include information about the physical volumes it contains. Given a device path or device key (akin to UUID) you can use one of the methods virStorageVolLookupByPath virStorageVolLookupByKey to retrieve a virStorageVolPtr object for it. Once you have one of these, then you can call virStorageVolGetInfo, to find out its capacity / allocation These two are not currently implemented in libvirt. The intent is though, that you can re-define the XML for an existing virStoragePoolPtr object, with PV devices added/removed from the XML. Then invoke the virStoragePoolBuild() method to actually make the changes to the underlying volume group. This is again possible with the virStoragePoolListVolumes() method once you have an active virStoragePoolPtr object for a volume group. Given a virStorageVolPtr object for a LV, you can call virStorageVolGetInfo to get size information, or virStorageVolGetXMLDesc() for more general metadata. Given a virStoragePoolPtr object refering to a volume group, you can use virStorageVolCreateXML() to allocate a new logical volume within it. Similarly virStorageVolDelete will remove a logical volume. All the method names I'm refering to here are the C apis. If you just want to experiment & play with the APIs to get a better understanding of them, the 'virsh' command line tool exposes practically all of the functionality in a fairly friendly manner. For example, using the virConnectFindStoragePoolSources() method to disocver LVM volume groups is possible with: # virsh find-storage-pool-sources-as logical <sources> <source> <device path='/dev/sda2'/> <name>HostVG</name> <format type='lvm2'/> </source> </sources> You can then use, virStoragePoolDefineXML with info by running the 'virsh pool-define' command, and so on - 'virsh help' will show you all the possible commands. Regards, Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|

On Wed, Nov 19, 2008 at 03:11:35PM -0500, David Lively wrote: It is a complicated situation :-) The standard Winsock API equivalent to socket() is called WSASocket() and returns a datatype SOCKET, which I believe is just an alias for HANDLE. GnuLib's goal is to fix non-POSIX-ness, so it provides a impl called socket() which returns an 'int' as per POSIX. Internally this is implemented by calling WSASocket(), and then using the _open_osfhandle() method to convert the SOCKET into a regular 'int' file handle which is compatible with Windows' UNIX API layer. eg close, ioctl, etc So, yes, you are correct, that regular Winsock is not compatible with int file handles, but by using GNUlib and the compat layer, we do re-gain proper compatability. The compatability works both ways - if an application using libvirt really does want the original SOCKET handle again, it can convert the file handle back. So _open_osfhandle() and _get_osfhandle() are idempotent MicroSoft have some docs on this here http://msdn.microsoft.com/en-us/library/bdts1c9x(VS.71).aspx http://msdn.microsoft.com/en-us/library/ks2530z6.aspx As an example, we use GNULIB in GTK-VNC too, and need to integrate with GLib event loop. GLib on Win32 is written to assume use of traditional SOCKET handles, so when we register the GTK-VNC socket with GLib, we use _get_osfhandle to convert the file descriptor back into a SOCKET handle. NB, the OSF handles are avialable in Win 98, Win Me, Win NT, Win 2000, Win XP We don't care about Win 95 so Win CE is the only currently existing Windows platform we'd be unable to support in this way. I'm personally not worried by this restriction... Regards, Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|