Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933248AbaKROsc (ORCPT ); Tue, 18 Nov 2014 09:48:32 -0500 Received: from cantor2.suse.de ([195.135.220.15]:56975 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754981AbaKROJ6 (ORCPT ); Tue, 18 Nov 2014 09:09:58 -0500 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, "Darrick J. Wong" , "Theodore Ts'o" , Jiri Slaby Subject: [PATCH 3.12 125/206] ext4: check s_chksum_driver when looking for bg csum presence Date: Tue, 18 Nov 2014 15:08:00 +0100 Message-Id: <9154dd792c9820b25d51e67e6e8e7ae277b64250.1416319692.git.jslaby@suse.cz> X-Mailer: git-send-email 2.1.3 In-Reply-To: <28f04bcc068a44c5641c727883947960fb8dcbd5.1416319692.git.jslaby@suse.cz> References: <28f04bcc068a44c5641c727883947960fb8dcbd5.1416319692.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Darrick J. Wong" 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- 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 bd5f351ef10b..29c4e30bf4ca 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2324,8 +2324,8 @@ 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 4ddd6cf12f63..64a94388bc8d 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2000,6 +2000,10 @@ 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)); -- 2.1.3 -- 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/