From: "Darrick J. Wong" Subject: [PATCH] ext4: Set barrier=0 when block device does not advertise flush support Date: Thu, 2 Dec 2010 16:16:59 -0800 Message-ID: <20101203001659.GI18195@tux1.beaverton.ibm.com> Reply-To: djwong@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel , linux-ext4 To: "Theodore Ts'o" Return-path: Received: from e35.co.us.ibm.com ([32.97.110.153]:42418 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758144Ab0LCAQ6 (ORCPT ); Thu, 2 Dec 2010 19:16:58 -0500 Content-Disposition: inline Sender: linux-ext4-owner@vger.kernel.org List-ID: If the user tries to enable write flushes with "barrier=1" and the underlying block device does not support flushes, print a message and set barrier=0. Signed-off-by: Darrick J. Wong --- fs/ext4/super.c | 14 ++++++++++++++ 1 files changed, 14 insertions(+), 0 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index e32195d..098dcf0 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3124,6 +3124,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) &journal_ioprio, NULL, 0)) goto failed_mount; + /* Catch barrier=1 and no flush support */ + if (test_opt(sb, BARRIER) && + !(sb->s_bdev->bd_disk->queue->flush_flags & REQ_FLUSH)) { + ext4_msg(sb, KERN_WARNING, "flush not supported; disabling."); + clear_opt(sbi->s_mount_opt, BARRIER); + } + sb->s_flags = (sb->s_flags & ~MS_POSIXACL) | (test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0); @@ -4198,6 +4205,13 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) goto restore_opts; } + /* Catch barrier=1 and no flush support */ + if (test_opt(sb, BARRIER) && + !(sb->s_bdev->bd_disk->queue->flush_flags & REQ_FLUSH)) { + ext4_msg(sb, KERN_WARNING, "flush not supported; disabling."); + clear_opt(sbi->s_mount_opt, BARRIER); + } + if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) ext4_abort(sb, "Abort forced by user");