New function nfs4_update_server() moves an nfs_server to a different
nfs_client. This is done as part of migration recovery.
Though it may be appealing to think of them as the same thing,
migration recovery is not the same as following a referral.
For a referral, the client has not descended into the file system
yet: it has no nfs_server, no super block, no inodes or open state.
It is enough to simply instantiate the nfs_server and super block,
and perform a referral mount.
For a migration, however, we have all of those things already, and
they have to be moved to a different nfs_client. No local namespace
changes are needed here.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/nfs/client.c | 3 +
fs/nfs/internal.h | 3 +
fs/nfs/nfs4client.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 113 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 2dceee4..f2e870c 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -943,7 +943,7 @@ void nfs_server_insert_lists(struct nfs_server *server)
}
EXPORT_SYMBOL_GPL(nfs_server_insert_lists);
-static void nfs_server_remove_lists(struct nfs_server *server)
+void nfs_server_remove_lists(struct nfs_server *server)
{
struct nfs_client *clp = server->nfs_client;
struct nfs_net *nn;
@@ -960,6 +960,7 @@ static void nfs_server_remove_lists(struct nfs_server *server)
synchronize_rcu();
}
+EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
/*
* Allocate and initialise a server record
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 38da8c2..e5a6bd1 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -154,6 +154,7 @@ struct nfs_client *nfs_get_client(const struct nfs_client_initdata *,
rpc_authflavor_t);
int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *, struct nfs_fattr *);
void nfs_server_insert_lists(struct nfs_server *);
+void nfs_server_remove_lists(struct nfs_server *);
void nfs_init_timeout_values(struct rpc_timeout *, int, unsigned int, unsigned int);
int nfs_init_server_rpcclient(struct nfs_server *, const struct rpc_timeout *t,
rpc_authflavor_t);
@@ -174,6 +175,8 @@ extern struct nfs_server *nfs4_create_server(
struct nfs_subversion *);
extern struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *,
struct nfs_fh *);
+extern int nfs4_update_server(struct nfs_server *server, const char *hostname,
+ struct sockaddr *sap, size_t salen);
extern void nfs_free_server(struct nfs_server *server);
extern struct nfs_server *nfs_clone_server(struct nfs_server *,
struct nfs_fh *,
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index a860ab5..299cf6b 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -1091,3 +1091,111 @@ error:
dprintk("<-- nfs4_create_referral_server() = error %d\n", error);
return ERR_PTR(error);
}
+
+/*
+ * Grab the destination's particulars, including lease expiry time.
+ *
+ * Returns zero if probe succeeded and retrieved FSID matches the FSID
+ * we have cached.
+ */
+static int nfs_probe_destination(struct nfs_server *server)
+{
+ struct inode *inode = server->super->s_root->d_inode;
+ struct nfs_fattr *fattr;
+ int error;
+
+ fattr = nfs_alloc_fattr();
+ if (fattr == NULL)
+ return -ENOMEM;
+
+ /* Sanity: the probe won't work if the destination server
+ * does not recognize the migrated FH. */
+ error = nfs_probe_fsinfo(server, NFS_FH(inode), fattr);
+
+ nfs_free_fattr(fattr);
+ return error;
+}
+
+/**
+ * nfs4_update_server - Move an nfs_server to a different nfs_client
+ *
+ * @server: represents FSID to be moved
+ * @hostname: new end-point's hostname
+ * @sap: new end-point's socket address
+ * @salen: size of "sap"
+ *
+ * The nfs_server must be quiescent before this function is invoked.
+ * Either its session is drained (NFSv4.1+), or its transport is
+ * plugged and drained (NFSv4.0).
+ *
+ * Returns zero on success, or a negative errno value.
+ */
+int nfs4_update_server(struct nfs_server *server, const char *hostname,
+ struct sockaddr *sap, size_t salen)
+{
+ struct nfs_client *clp = server->nfs_client;
+ struct rpc_clnt *clnt = server->client;
+ struct xprt_create xargs = {
+ .ident = clp->cl_proto,
+ .net = &init_net,
+ .dstaddr = sap,
+ .addrlen = salen,
+ .servername = hostname,
+ };
+ char buf[INET6_ADDRSTRLEN + 1];
+ struct sockaddr_storage address;
+ struct sockaddr *localaddr = (struct sockaddr *)&address;
+ int error;
+
+ dprintk("--> %s: move FSID %llx:%llx to \"%s\")\n", __func__,
+ (unsigned long long)server->fsid.major,
+ (unsigned long long)server->fsid.minor,
+ hostname);
+
+ error = rpc_switch_client_transport(clnt, &xargs, clnt->cl_timeout);
+ if (error != 0) {
+ dprintk("<-- %s(): rpc_switch_client_transport returned %d\n",
+ __func__, error);
+ goto out;
+ }
+
+ error = rpc_localaddr(clnt, localaddr, sizeof(address));
+ if (error != 0) {
+ dprintk("<-- %s(): rpc_localaddr returned %d\n",
+ __func__, error);
+ goto out;
+ }
+
+ error = -EAFNOSUPPORT;
+ if (rpc_ntop(localaddr, buf, sizeof(buf)) == 0) {
+ dprintk("<-- %s(): rpc_ntop returned %d\n",
+ __func__, error);
+ goto out;
+ }
+
+ nfs_server_remove_lists(server);
+ error = nfs4_set_client(server, hostname, sap, salen, buf,
+ clp->cl_rpcclient->cl_auth->au_flavor,
+ clp->cl_proto, clnt->cl_timeout,
+ clp->cl_minorversion, clp->cl_net);
+ nfs_put_client(clp);
+ if (error != 0) {
+ nfs_server_insert_lists(server);
+ dprintk("<-- %s(): nfs4_set_client returned %d\n",
+ __func__, error);
+ goto out;
+ }
+
+ if (server->nfs_client->cl_hostname == NULL)
+ server->nfs_client->cl_hostname = kstrdup(hostname, GFP_KERNEL);
+ nfs_server_insert_lists(server);
+
+ error = nfs_probe_destination(server);
+ if (error < 0)
+ goto out;
+
+ dprintk("<-- %s() succeeded\n", __func__);
+
+out:
+ return error;
+}
--
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