NFS: Reduce the stack footprint of nfs_follow_remote_path()

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index b4148fc..fa3111e 100644 (file)
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2672,38 +2672,44 @@ out_freepage:
 static int nfs_follow_remote_path(struct vfsmount *root_mnt,
                const char *export_path, struct vfsmount *mnt_target)
 {
+       struct nameidata *nd = NULL;
        struct mnt_namespace *ns_private;
-       struct nameidata nd;
        struct super_block *s;
        int ret;
 
+       nd = kmalloc(sizeof(*nd), GFP_KERNEL);
+       if (nd == NULL)
+               return -ENOMEM;
+
        ns_private = create_mnt_ns(root_mnt);
        ret = PTR_ERR(ns_private);
        if (IS_ERR(ns_private))
                goto out_mntput;
 
        ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
-                       export_path, LOOKUP_FOLLOW, &nd);
+                       export_path, LOOKUP_FOLLOW, nd);
 
        put_mnt_ns(ns_private);
 
        if (ret != 0)
                goto out_err;
 
-       s = nd.path.mnt->mnt_sb;
+       s = nd->path.mnt->mnt_sb;
        atomic_inc(&s->s_active);
        mnt_target->mnt_sb = s;
-       mnt_target->mnt_root = dget(nd.path.dentry);
+       mnt_target->mnt_root = dget(nd->path.dentry);
 
        /* Correct the device pathname */
-       nfs_fix_devname(&nd.path, mnt_target);
+       nfs_fix_devname(&nd->path, mnt_target);
 
-       path_put(&nd.path);
+       path_put(&nd->path);
+       kfree(nd);
        down_write(&s->s_umount);
        return 0;
 out_mntput:
        mntput(root_mnt);
 out_err:
+       kfree(nd);
        return ret;
 }