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 minor version 1 introduces "fs_locations_info" which
extends the sorting information 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 | 162 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 164 insertions(+), 0 deletions(-)
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 58a9ad7..bf2a4e7 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -164,6 +164,8 @@ static inline void nfs_fs_proc_exit(void)
/* nfs4namespace.c */
#ifdef CONFIG_NFS_V4
extern struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, 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(const struct vfsmount *mnt_parent, struct dentry *dentry)
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 3c2a172..ea591ff 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -270,3 +270,165 @@ 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,
+ };
+ 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 active_tasks,
+ * so rpc_lock_client() can't make any progress.
+ */
+#if 0
+ error = rpc_lock_client(clnt, clnt->cl_timeout->to_maxval);
+ if (error != 0)
+ goto out;
+#endif
+
+ error = rpc_switch_client_transport(clnt, &xargs, clnt->cl_timeout);
+
+out:
+#if 0
+ rpc_unlock_client(clnt);
+#endif
+ dprintk("<-- %s() = %d\n", __func__, error);
+ 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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