ceph: ceph_get_inode() returns an ERR_PTR

ceph_get_inode() returns an ERR_PTR and it doesn't return a NULL.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/inode.c

@@ -1230,11 +1230,11 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
 			in = dn->d_inode;
 		} else {
 			in = ceph_get_inode(parent->d_sb, vino);
-			if (in == NULL) {
+			if (IS_ERR(in)) {
 				dout("new_inode badness\n");
 				d_delete(dn);
 				dput(dn);
-				err = -ENOMEM;
+				err = PTR_ERR(in);
 				goto out;
 			}
 			dn = splice_dentry(dn, in, NULL);