mm: bdi init hooks

provide BDI constructor/destructor hooks

[akpm@linux-foundation.org: compile fix]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index a532ee1..70587f3 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -627,6 +627,7 @@
 	if (server->rsize > NFS_MAX_FILE_IO_SIZE)
 		server->rsize = NFS_MAX_FILE_IO_SIZE;
 	server->rpages = (server->rsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+
 	server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD;
 
 	if (server->wsize > max_rpc_payload)
@@ -677,6 +678,10 @@
 		goto out_error;
 
 	nfs_server_set_fsinfo(server, &fsinfo);
+	error = bdi_init(&server->backing_dev_info);
+	if (error)
+		goto out_error;
+
 
 	/* Get some general file system info */
 	if (server->namelen == 0) {
@@ -756,6 +761,7 @@
 	nfs_put_client(server->nfs_client);
 
 	nfs_free_iostats(server->io_stats);
+	bdi_destroy(&server->backing_dev_info);
 	kfree(server);
 	nfs_release_automount_timer();
 	dprintk("<-- nfs_free_server()\n");