@@ -4030,6 +4030,32 @@ static void nfs4_init_boot_verifier(const struct nfs_client *clp,
memcpy(bootverf->data, verf, sizeof(bootverf->data));
}
+static unsigned int
+nfs4_init_nonuniform_client_string(const struct nfs_client *clp,
+ char *buf, size_t len)
+{
+ unsigned int result;
+
+ rcu_read_lock();
+ result = scnprintf(buf, len, "Linux NFSv4.0 %s/%s %s",
+ clp->cl_ipaddr,
+ rpc_peeraddr2str(clp->cl_rpcclient,
+ RPC_DISPLAY_ADDR),
+ rpc_peeraddr2str(clp->cl_rpcclient,
+ RPC_DISPLAY_PROTO));
+ rcu_read_unlock();
+ return result;
+}
+
+static unsigned int
+nfs4_init_uniform_client_string(const struct nfs_client *clp,
+ char *buf, size_t len)
+{
+ return scnprintf(buf, len, "Linux NFSv%u.%u %s",
+ clp->rpc_ops->version, clp->cl_minorversion,
+ clp->cl_rpcclient->cl_nodename);
+}
+
/**
* nfs4_proc_setclientid - Negotiate client ID
* @clp: state data structure
@@ -4060,15 +4086,18 @@ int nfs4_proc_setclientid(struct nfs_client *clp, u32 program,
/* nfs_client_id4 */
nfs4_init_boot_verifier(clp, &sc_verifier);
- rcu_read_lock();
- setclientid.sc_name_len = scnprintf(setclientid.sc_name,
- sizeof(setclientid.sc_name), "%s/%s %s",
- clp->cl_ipaddr,
- rpc_peeraddr2str(clp->cl_rpcclient,
- RPC_DISPLAY_ADDR),
- rpc_peeraddr2str(clp->cl_rpcclient,
- RPC_DISPLAY_PROTO));
+ if (test_bit(NFS_CS_MIGRATION, &clp->cl_flags))
+ setclientid.sc_name_len =
+ nfs4_init_uniform_client_string(clp,
+ setclientid.sc_name,
+ sizeof(setclientid.sc_name));
+ else
+ setclientid.sc_name_len =
+ nfs4_init_nonuniform_client_string(clp,
+ setclientid.sc_name,
+ sizeof(setclientid.sc_name));
/* cb_client4 */
+ rcu_read_lock();
setclientid.sc_netid_len = scnprintf(setclientid.sc_netid,
sizeof(setclientid.sc_netid),
rpc_peeraddr2str(clp->cl_rpcclient,
@@ -5294,10 +5323,8 @@ int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
};
nfs4_init_boot_verifier(clp, &verifier);
- args.id_len = scnprintf(args.id, sizeof(args.id),
- "%s/%s",
- clp->cl_ipaddr,
- clp->cl_rpcclient->cl_nodename);
+ args.id_len = nfs4_init_uniform_client_string(clp, args.id,
+ sizeof(args.id));
dprintk("NFS call exchange_id auth=%s, '%.*s'\n",
clp->cl_rpcclient->cl_auth->au_ops->au_name,
args.id_len, args.id);
Currently, when identifying itself to NFS servers, the Linux NFS client uses a unique nfs_client_id4.id string for each server IP address it talks with. For example, when client A talks to server X, the client identifies itself using a string like "AX". These strings are opaque to servers. Each client is free to choose any content, as long as it is unique from other client instances. A server must not parse the contents of the string, it can only test these strings for equality. These requirements are specified in detail by RFC 3530 (and bis). This form of client identification presents a problem for Transparent State Migration. When client A's state on server X is migrated to server Y, it continues to be associated with string "AX." But, according to the rules of client string construction above, client A will present string "AY" when communicating with server Y. Server Y thus has no way to know that client A should be associated with the state migrated from server X. "AX" is all but abandoned, interferring with establishing fresh state for A on server Y. To support transparent state migration, then, NFSv4.0 clients must instead use the same nfs_client_id4.id string to identify themselves to every NFS server; something like "A". As part of a migration event, when state associated with string "A" shows up at server Y, client A identifies itself as "A" and server Y will know immediately that the state associated with "A," whether it is native or migrated, is owned by client A. As a pre-requisite to adding support for NFSv4 migration to the Linux NFS client, this patch changes the way Linux identifies itself to NFS servers via the SETCLIENTID (NFSv4 minor version 0) and EXCHANGE_ID (NFSv4 minor version 1) operations. In addition to removing the server's IP address from nfs_client_id4, the Linux NFS client will also no longer use its own source IP address as part of the nfs_client_id4 string. On multi-homed clients, the value of this address depends on the address family and network routing used to contact the server, thus it can be different for each server. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> --- fs/nfs/nfs4proc.c | 51 +++++++++++++++++++++++++++++++++++++++------------ 1 files changed, 39 insertions(+), 12 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html