From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ric Wheeler Subject: Re: [PATCH] ext4: Ensure writecache to disk in no journal mode Date: Fri, 26 Mar 2010 13:16:19 -0400 Message-ID: <4BACEBE3.50108@redhat.com> References: <1269620462-25906-1-git-send-email-surbhi.palande@canonical.com> <87pr2rhwe0.fsf@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Surbhi Palande , linux-ext4@vger.kernel.org, Theodore Tso To: Dmitry Monakhov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:6685 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751426Ab0CZRPy (ORCPT ); Fri, 26 Mar 2010 13:15:54 -0400 In-Reply-To: <87pr2rhwe0.fsf@openvz.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 03/26/2010 12:37 PM, Dmitry Monakhov wrote: > Surbhi Palande writes: > > >> Ensure that in the no journal mode the write cache is flushed to the disk by >> calling a blkdev_issue_flush() which issues a WRITE_BARRIER if necessary. >> > As soon as i understand, nojournal mode is assumed to be used for > fail-free block devices(raid + UPS). So we don't have to worry about > blkdev's wcache vs persistent storage correctness. > I don't think that is a safe assumption. If users want that behavior, they can mount with fs without barriers... ric >> Signed-off-by: Surbhi Palande >> --- >> fs/ext4/fsync.c | 8 ++++++-- >> 1 files changed, 6 insertions(+), 2 deletions(-) >> >> diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c >> index d6049e4..1d73a50 100644 >> --- a/fs/ext4/fsync.c >> +++ b/fs/ext4/fsync.c >> @@ -67,8 +67,12 @@ int ext4_sync_file(struct file *file, struct dentry *dentry, int datasync) >> if (ret< 0) >> return ret; >> >> - if (!journal) >> - return simple_fsync(file, dentry, datasync); >> + if (!journal) { >> + ret = simple_fsync(file, dentry, datasync); >> + if (test_opt(inode->i_sb, BARRIER)) >> + blkdev_issue_flush(inode->i_sb->s_bdev, NULL); >> + return ret; >> + } >> >> /* >> * data=writeback,ordered: >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >