From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:47732 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728335AbeICVzL (ORCPT ); Mon, 3 Sep 2018 17:55:11 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andreas Dilger , Arnd Bergmann , Theodore Tso Subject: [PATCH 4.18 043/123] ext4: sysfs: print ext4_super_block fields as little-endian Date: Mon, 3 Sep 2018 18:56:27 +0200 Message-Id: <20180903165721.289965138@linuxfoundation.org> In-Reply-To: <20180903165719.499675257@linuxfoundation.org> References: <20180903165719.499675257@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann commit a4d2aadca184ece182418950d45ba4ffc7b652d2 upstream. While working on extended rand for last_error/first_error timestamps, I noticed that the endianess is wrong; we access the little-endian fields in struct ext4_super_block as native-endian when we print them. This adds a special case in ext4_attr_show() and ext4_attr_store() to byteswap the superblock fields if needed. In older kernels, this code was part of super.c, it got moved to sysfs.c in linux-4.4. Cc: stable@vger.kernel.org Fixes: 52c198c6820f ("ext4: add sysfs entry showing whether the fs contains errors") Reviewed-by: Andreas Dilger Signed-off-by: Arnd Bergmann Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/sysfs.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) --- a/fs/ext4/sysfs.c +++ b/fs/ext4/sysfs.c @@ -274,8 +274,12 @@ static ssize_t ext4_attr_show(struct kob case attr_pointer_ui: if (!ptr) return 0; - return snprintf(buf, PAGE_SIZE, "%u\n", - *((unsigned int *) ptr)); + if (a->attr_ptr == ptr_ext4_super_block_offset) + return snprintf(buf, PAGE_SIZE, "%u\n", + le32_to_cpup(ptr)); + else + return snprintf(buf, PAGE_SIZE, "%u\n", + *((unsigned int *) ptr)); case attr_pointer_atomic: if (!ptr) return 0; @@ -308,7 +312,10 @@ static ssize_t ext4_attr_store(struct ko ret = kstrtoul(skip_spaces(buf), 0, &t); if (ret) return ret; - *((unsigned int *) ptr) = t; + if (a->attr_ptr == ptr_ext4_super_block_offset) + *((__le32 *) ptr) = cpu_to_le32(t); + else + *((unsigned int *) ptr) = t; return len; case attr_inode_readahead: return inode_readahead_blks_store(sbi, buf, len);