Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753503AbaKFWrr (ORCPT ); Thu, 6 Nov 2014 17:47:47 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:59159 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753322AbaKFWoZ (ORCPT ); Thu, 6 Nov 2014 17:44:25 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Darrick J. Wong" , "Theodore Ts'o" , Kamal Mostafa Subject: [PATCH 3.13 074/162] ext4: check s_chksum_driver when looking for bg csum presence Date: Thu, 6 Nov 2014 14:35:38 -0800 Message-Id: <1415313426-9622-75-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1415313426-9622-1-git-send-email-kamal@canonical.com> References: <1415313426-9622-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11.11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "Darrick J. Wong" commit 813d32f91333e4c33d5a19b67167c4bae42dae75 upstream. Convert the ext4_has_group_desc_csum predicate to look for a checksum driver instead of the metadata_csum flag and change the bg checksum calculation function to look for GDT_CSUM before taking the crc16 path. Without this patch, if we mount with ^uninit_bg,^metadata_csum and later metadata_csum gets turned on by accident, the block group checksum functions will incorrectly assume that checksumming is enabled (metadata_csum) but that crc16 should be used (!s_chksum_driver). This is totally wrong, so fix the predicate and the checksum formula selection. (Granted, if the metadata_csum feature bit gets enabled on a live FS then something underhanded is going on, but we could at least avoid writing garbage into the on-disk fields.) Signed-off-by: Darrick J. Wong Signed-off-by: Theodore Ts'o Reviewed-by: Dmitry Monakhov Signed-off-by: Kamal Mostafa --- fs/ext4/ext4.h | 4 ++-- fs/ext4/super.c | 4 ++++ 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 5b250fe..bfb7fed 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2337,8 +2337,8 @@ extern int ext4_register_li_request(struct super_block *sb, static inline int ext4_has_group_desc_csum(struct super_block *sb) { return EXT4_HAS_RO_COMPAT_FEATURE(sb, - EXT4_FEATURE_RO_COMPAT_GDT_CSUM | - EXT4_FEATURE_RO_COMPAT_METADATA_CSUM); + EXT4_FEATURE_RO_COMPAT_GDT_CSUM) || + (EXT4_SB(sb)->s_chksum_driver != NULL); } static inline int ext4_has_metadata_csum(struct super_block *sb) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 6686ce4..608db58 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2019,6 +2019,10 @@ static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group, } /* old crc16 code */ + if (!(sbi->s_es->s_feature_ro_compat & + cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM))) + return 0; + offset = offsetof(struct ext4_group_desc, bg_checksum); crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid)); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/