Hi Stefan- > On Jun 30, 2017, at 9:21 AM, Stefan Hajnoczi <stefanha@xxxxxxxxxx> wrote: > > Neither libtirpc nor getprotobyname(3) know about AF_VSOCK. Why? Basically you are building a lot of specialized awareness in applications and leaving the network layer alone. That seems backwards to me. > For similar > reasons as for "rdma"/"rmda6", translate "vsock" manually in getport.c. rdma/rdma6 are specified by standards, and appear in the IANA Network Identifiers database: https://www.iana.org/assignments/rpc-netids/rpc-netids.xhtml Is there a standard netid for vsock? If not, there needs to be some discussion with the nfsv4 Working Group to get this worked out. Because AF_VSOCK is an address family and the RPC framing is the same as TCP, the netid should be something like "tcpv" and not "vsock". I've complained about this before and there has been no response of any kind. I'll note that rdma/rdma6 do not use alternate address families: an IP address is specified and mapped to a GUID by the underlying transport. We purposely did not expose GUIDs to NFS, which is based on AF_INET/AF_INET6. rdma co-exists with IP. vsock doesn't have this fallback. It might be a better approach to use well-known (say, link-local or loopback) addresses and let the underlying network layer figure it out. Then hide all this stuff with DNS and let the client mount the server by hostname and use normal sockaddr's and "proto=tcp". Then you don't need _any_ application layer changes. Without hostnames, how does a client pick a Kerberos service principal for the server? Does rpcbind implement "vsock" netids? Does the NFSv4.0 client advertise "vsock" in SETCLIENTID, and provide a "vsock" callback service? > It is now possible to mount a file system from the host (hypervisor) > over AF_VSOCK like this: > > (guest)$ mount.nfs 2:/export /mnt -v -o clientaddr=3,proto=vsock > > The VM's cid address is 3 and the hypervisor is 2. The mount command is supposed to supply "clientaddr" automatically. This mount option is exposed only for debugging purposes or very special cases (like disabling NFSv4 callback operations). I mean the whole point of this exercise is to get rid of network configuration, but here you're adding the need to additionally specify both the proto option and the clientaddr option to get this to work. Seems like that isn't zero-configuration at all. Wouldn't it be nicer if it worked like this: (guest)$ cat /etc/hosts 129.0.0.2 localhyper (guest)$ mount.nfs localhyper:/export /mnt And the result was a working NFS mount of the local hypervisor, using whatever NFS version the two both support, with no changes needed to the NFS implementation or the understanding of the system administrator? > Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx> > --- > support/nfs/getport.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > diff --git a/support/nfs/getport.c b/support/nfs/getport.c > index 081594c..0b857af 100644 > --- a/support/nfs/getport.c > +++ b/support/nfs/getport.c > @@ -217,8 +217,7 @@ nfs_get_proto(const char *netid, sa_family_t *family, unsigned long *protocol) > struct protoent *proto; > > /* > - * IANA does not define a protocol number for rdma netids, > - * since "rdma" is not an IP protocol. > + * IANA does not define protocol numbers for non-IP netids. > */ > if (strcmp(netid, "rdma") == 0) { > *family = AF_INET; > @@ -230,6 +229,11 @@ nfs_get_proto(const char *netid, sa_family_t *family, unsigned long *protocol) > *protocol = NFSPROTO_RDMA; > return 1; > } > + if (strcmp(netid, "vsock") == 0) { > + *family = AF_VSOCK; > + *protocol = 0; > + return 1; > + } > > nconf = getnetconfigent(netid); > if (nconf == NULL) > @@ -258,14 +262,18 @@ nfs_get_proto(const char *netid, sa_family_t *family, unsigned long *protocol) > struct protoent *proto; > > /* > - * IANA does not define a protocol number for rdma netids, > - * since "rdma" is not an IP protocol. > + * IANA does not define protocol numbers for non-IP netids. > */ > if (strcmp(netid, "rdma") == 0) { > *family = AF_INET; > *protocol = NFSPROTO_RDMA; > return 1; > } > + if (strcmp(netid, "vsock") == 0) { > + *family = AF_VSOCK; > + *protocol = 0; > + return 1; > + } > > proto = getprotobyname(netid); > if (proto == NULL) > -- > 2.9.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Chuck Lever -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
