From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753953AbdK0RhR (ORCPT ); Mon, 27 Nov 2017 12:37:17 -0500 Received: from mga07.intel.com ([134.134.136.100]:38106 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752607AbdK0RhQ (ORCPT ); Mon, 27 Nov 2017 12:37:16 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,465,1505804400"; d="scan'208";a="181154589" From: Andi Kleen To: tytso@mit.edu Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andi Kleen Subject: [PATCH] ext4: Support fast symlinks from ext3 file systems Date: Mon, 27 Nov 2017 09:37:09 -0800 Message-Id: <20171127173709.20787-1-andi@firstfloor.org> X-Mailer: git-send-email 2.13.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andi Kleen dbb3c27f5b91c4 (ext4: change fast symlink test to not rely on i_blocks) broke ~10 years old ext3 file systems created by 2.6.17. Any ELF executable fails because the /lib/ld-linux.so.2 fast symlink cannot be read anymore. The patch assumed fast symlinks were created in a specific way, but that's not true on these really old file systems. The new behavior is apparently needed only with the large EA inode feature. Revert to the old behavior if the large EA inode feature is not set. This makes my old VM boot again. Fixes: dbb3c27f5b91c4 (ext4: change fast symlink test to not rely ...) Signed-off-by: Andi Kleen --- fs/ext4/inode.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 0992d76f7ab1..6b82b0ff5e0b 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -149,6 +149,15 @@ static int ext4_meta_trans_blocks(struct inode *inode, int lblocks, */ int ext4_inode_is_fast_symlink(struct inode *inode) { + if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) { + int ea_blocks = EXT4_I(inode)->i_file_acl ? + EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0; + + if (ext4_has_inline_data(inode)) + return 0; + + return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0); + } return S_ISLNK(inode->i_mode) && inode->i_size && (inode->i_size < EXT4_N_BLOCKS * 4); } -- 2.13.6