ceph: allocate and parse mount args before client instance

This simplifies much of the error handling during mount.  It also means
that we have the mount args before client creation, and we can initialize
based on those options.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index c7d673f..bf53581 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -600,8 +600,8 @@
 		pr_warning("writepage_start %p on forced umount\n", inode);
 		return -EIO; /* we're in a forced umount, don't write! */
 	}
-	if (client->mount_args.wsize && client->mount_args.wsize < wsize)
-		wsize = client->mount_args.wsize;
+	if (client->mount_args->wsize && client->mount_args->wsize < wsize)
+		wsize = client->mount_args->wsize;
 	if (wsize < PAGE_CACHE_SIZE)
 		wsize = PAGE_CACHE_SIZE;
 	max_pages_ever = wsize >> PAGE_CACHE_SHIFT;