+ top = grab_top(SDCARDFS_I(inode));
+
+ if (!top) {
+ release_top(SDCARDFS_I(inode));
+ return -EINVAL;
+ }
+
+ /*
+ * Permission check on sdcardfs inode.
+ * Calling process should have AID_SDCARD_RW permission
+ * Since generic_permission only needs i_mode, i_uid,
+ * i_gid, and i_sb, we can create a fake inode to pass
+ * this information down in.
+ *
+ * The underlying code may attempt to take locks in some
+ * cases for features we're not using, but if that changes,
+ * locks must be dealt with to avoid undefined behavior.
+ *
+ */
+ copy_attrs(&tmp, inode);
+ tmp.i_uid = make_kuid(&init_user_ns, SDCARDFS_I(top)->d_uid);
+ tmp.i_gid = make_kgid(&init_user_ns, get_gid(mnt, SDCARDFS_I(top)));
+ tmp.i_mode = (inode->i_mode & S_IFMT) | get_mode(mnt, SDCARDFS_I(top));
+ tmp.i_size = i_size_read(inode);
+ release_top(SDCARDFS_I(inode));
+ tmp.i_sb = inode->i_sb;