From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: [PATCH] ext2, ext4: warn when mounting with dax enabled Date: Fri, 2 Oct 2015 16:16:05 +0200 Message-ID: <20151002141605.GC14603@quack.suse.cz> References: <20150929194806.5276.863.stgit@dwillia2-desk3.jf.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: ross.zwisler@linux.intel.com, david@fromorbit.com, Theodore Ts'o , linux-nvdimm@lists.01.org, Andreas Dilger , Jan Kara , linux-fsdevel@vger.kernel.org, Matthew Wilcox , linux-ext4@vger.kernel.org, "Kirill A. Shutemov" To: Dan Williams Return-path: Received: from mx2.suse.de ([195.135.220.15]:45816 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752018AbbJBOQK (ORCPT ); Fri, 2 Oct 2015 10:16:10 -0400 Content-Disposition: inline In-Reply-To: <20150929194806.5276.863.stgit@dwillia2-desk3.jf.intel.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue 29-09-15 15:48:11, Dan Williams wrote: > Similar to XFS warn when mounting DAX while it is still considered under > development. Also, aspects of the DAX implementation, for example > synchronization against multiple faults and faults causing block > allocation, depend on the correct implementation in the filesystem. The > maturity of a given DAX implementation is filesystem specific. > > Cc: Jan Kara > Cc: "Theodore Ts'o" > Cc: Andreas Dilger > Cc: Matthew Wilcox > Cc: linux-ext4@vger.kernel.org > Cc: Kirill A. Shutemov > Reported-by: Dave Chinner > Signed-off-by: Dan Williams Agreed. You can add: Acked-by: Jan Kara Honza > --- > Given the pending investigations [1], and rather than marking FS_DAX > broken, warn about DAX usage until we've landed fixes for the issues > that Dave has identified. > > [1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002266.html > > fs/ext2/super.c | 2 ++ > fs/ext4/super.c | 6 +++++- > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/fs/ext2/super.c b/fs/ext2/super.c > index 900e19cf9ef6..2597b0663bf2 100644 > --- a/fs/ext2/super.c > +++ b/fs/ext2/super.c > @@ -566,6 +566,8 @@ static int parse_options(char *options, struct super_block *sb) > /* Fall through */ > case Opt_dax: > #ifdef CONFIG_FS_DAX > + ext2_msg(sb, KERN_WARNING, > + "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); > set_opt(sbi->s_mount_opt, DAX); > #else > ext2_msg(sb, KERN_INFO, "dax option not supported"); > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index a63c7b0a10cf..4db6eb0b6979 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -1656,8 +1656,12 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token, > } > sbi->s_jquota_fmt = m->mount_opt; > #endif > -#ifndef CONFIG_FS_DAX > } else if (token == Opt_dax) { > +#ifdef CONFIG_FS_DAX > + ext4_msg(sb, KERN_WARNING, > + "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); > + sbi->s_mount_opt |= m->mount_opt; > +#else > ext4_msg(sb, KERN_INFO, "dax option not supported"); > return -1; > #endif > > -- Jan Kara SUSE Labs, CR