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/nfs4_fs.h | 2 +
fs/nfs/nfs4namespace.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 103 insertions(+)
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 28842ab..fcae728 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -217,6 +217,8 @@ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
struct nfs_fh *, struct nfs_fattr *);
+int nfs4_replace_transport(struct nfs_server *server,
+ const struct nfs4_fs_locations *locations);
/* nfs4proc.c */
extern int nfs4_proc_setclientid(struct nfs_client *, u32, unsigned short, struct rpc_cred *, struct nfs4_setclientid_res *);
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 2288cd3..ebd8b06 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -400,3 +400,104 @@ out:
rpc_shutdown_client(client);
return mnt;
}
+
+/*
+ * 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;
+
+ sap = kmalloc(addr_bufsize, GFP_KERNEL);
+ if (sap == NULL)
+ return -ENOMEM;
+
+ 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;
+
+ if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
+ continue;
+
+ salen = nfs_parse_server_name(buf->data, buf->len,
+ sap, addr_bufsize, server);
+ 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);
+ 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;
+
+ 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);
+ return error;
+}
--
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