Introduce functions that can walk through an array of returned
fs_locations information and connect a transport to one of the
destination servers listed therein.
Note that NFS minor version 1 introduces "fs_locations_info" which
extends the locations array sorting criteria available to clients.
This is not supported yet.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/nfs/internal.h | 2
fs/nfs/nfs4namespace.c | 202 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 204 insertions(+), 0 deletions(-)
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 0bf4e67..191c5b4 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -177,6 +177,8 @@ static inline void nfs_fs_proc_exit(void)
/* nfs4namespace.c */
#ifdef CONFIG_NFS_V4
extern struct vfsmount *nfs_do_refmount(struct dentry *dentry);
+extern int nfs4_replace_transport(struct nfs_server *server,
+ const struct nfs4_fs_locations *locations);
#else
static inline
struct vfsmount *nfs_do_refmount(struct dentry *dentry)
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index bb80c49..2fa024c 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -22,6 +22,8 @@
#define NFSDBG_FACILITY NFSDBG_VFS
+#undef USE_RPC_LOCK_CLIENT
+
/*
* Convert the NFSv4 pathname components into a standard posix path.
*
@@ -263,3 +265,203 @@ out:
dprintk("%s: done\n", __func__);
return mnt;
}
+
+#undef NFSDBG_FACILITY
+#define NFSDBG_FACILITY NFSDBG_CLIENT
+
+/*
+ * Returns zero on success, or a negative errno value.
+ */
+static 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);
+
+ /*
+ * rpc_lock_client() deadlocks here. This is because the tasks
+ * that received NFS4ERR_MOVED are waiting for us to wake them
+ * when we are done recovering. But they have bumped
+ * cl_active_tasks for this clnt, so rpc_lock_client() can't make
+ * any progress.
+ */
+#ifdef USE_RPC_LOCK_CLIENT
+ error = rpc_lock_client(clnt, clnt->cl_timeout->to_maxval);
+ if (error != 0) {
+ dprintk("<-- %s(): rpc_lock_client returned %d\n",
+ __func__, error);
+ goto out;
+ }
+#endif /* USE_RPC_LOCK_CLIENT */
+
+ 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;
+ }
+
+ /*
+ * If we were able to contact the server at @sap, set up a new
+ * nfs_client and move @server to it.
+ */
+ 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;
+ }
+ error = nfs4_clone_client(clp, sap, salen, buf, server);
+ if (error != 0) {
+ dprintk("<-- %s(): nfs4_clone_client returned %d\n",
+ __func__, error);
+ goto out;
+ }
+ if (server->nfs_client->cl_hostname == NULL)
+ server->nfs_client->cl_hostname = kstrdup(hostname, GFP_KERNEL);
+
+ dprintk("<-- %s() succeeded\n", __func__);
+
+out:
+#ifdef USE_RPC_LOCK_CLIENT
+ rpc_unlock_client(clnt);
+#endif /* USE_RPC_LOCK_CLIENT */
+ return error;
+}
+
+/*
+ * Try one location from the fs_locations array.
+ *
+ * Returns zero on success, or a negative errno value.
+ */
+static int nfs4_try_replacing_one_location(struct nfs_server *server,
+ char *page, char *page2,
+ const struct nfs4_fs_location *location)
+{
+ const size_t addr_bufsize = sizeof(struct sockaddr_storage);
+ struct sockaddr *sap;
+ unsigned int s;
+ size_t salen;
+ int error;
+
+ dprintk("--> %s(%llx:%llx)\n", __func__,
+ (unsigned long long)server->fsid.major,
+ (unsigned long long)server->fsid.minor);
+
+ error = -ENOMEM;
+ sap = kmalloc(addr_bufsize, GFP_KERNEL);
+ if (sap == NULL)
+ goto out;
+
+ error = -ENOENT;
+ for (s = 0; s < location->nservers; s++) {
+ const struct nfs4_string *buf = &location->servers[s];
+ char *hostname;
+
+ if (buf->len <= 0 || buf->len > PAGE_SIZE)
+ continue;
+
+ /* XXX: IPv6 not supported? */
+ if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
+ continue;
+
+ salen = nfs_parse_server_name(buf->data, buf->len,
+ sap, addr_bufsize);
+ if (salen == 0)
+ continue;
+ rpc_set_port(sap, NFS_PORT);
+
+ error = -ENOMEM;
+ hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
+ if (hostname == NULL)
+ break;
+
+ error = nfs4_update_server(server, hostname, sap, salen);
+ kfree(hostname);
+ if (error == 0)
+ break;
+ }
+
+ kfree(sap);
+out:
+ dprintk("<-- %s() = %d\n", __func__, error);
+ return error;
+}
+
+/**
+ * nfs4_replace_transport - set up transport to destination server
+ *
+ * @server: export being migrated
+ * @locations: fs_locations array
+ *
+ * Returns zero on success, or a negative errno value.
+ *
+ * The client tries all the entries in the "locations" array, in the
+ * order returned by the server, until one works or the end of the
+ * array is reached.
+ */
+int nfs4_replace_transport(struct nfs_server *server,
+ const struct nfs4_fs_locations *locations)
+{
+ char *page = NULL, *page2 = NULL;
+ int loc, error;
+
+ dprintk("--> %s(%llx:%llx)\n", __func__,
+ (unsigned long long)server->fsid.major,
+ (unsigned long long)server->fsid.minor);
+
+ error = -ENOENT;
+ if (locations == NULL || locations->nlocations <= 0)
+ goto out;
+
+ error = -ENOMEM;
+ page = (char *) __get_free_page(GFP_USER);
+ if (!page)
+ goto out;
+ page2 = (char *) __get_free_page(GFP_USER);
+ if (!page2)
+ goto out;
+
+ for (loc = 0; loc < locations->nlocations; loc++) {
+ const struct nfs4_fs_location *location =
+ &locations->locations[loc];
+
+ if (location == NULL || location->nservers <= 0 ||
+ location->rootpath.ncomponents == 0)
+ continue;
+
+ error = nfs4_try_replacing_one_location(server, page,
+ page2, location);
+ if (error == 0)
+ break;
+ }
+
+out:
+ free_page((unsigned long)page);
+ free_page((unsigned long)page2);
+
+ dprintk("<-- %s() = %d\n", __func__, error);
+ return error;
+}
--
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