From: Liu Bo <bo.li.liu@oracle.com>
To: dsterba@suse.cz, linux-btrfs@vger.kernel.org, fdmanana@suse.com
Subject: Re: [RFC PATCH v2 1/2] Btrfs: add noi_version option to disable MS_I_VERSION
Date: Thu, 18 Jun 2015 10:46:09 +0800 [thread overview]
Message-ID: <20150618024607.GA8530@localhost.localdomain> (raw)
In-Reply-To: <20150617170118.GA6761@twin.jikos.cz>
On Wed, Jun 17, 2015 at 07:01:18PM +0200, David Sterba wrote:
> On Wed, Jun 17, 2015 at 11:52:36PM +0800, Liu Bo wrote:
> > On Wed, Jun 17, 2015 at 05:33:06PM +0200, David Sterba wrote:
> > > On Wed, Jun 17, 2015 at 03:54:31PM +0800, Liu Bo wrote:
> > > > MS_I_VERSION is enabled by default for btrfs, this adds an alternative
> > > > option to toggle it off.
> > >
> > > There's an existing generic iversion/noiversion mount option pair, no
> > > need to extra add it to btrfs.
> >
> > I know, it doesn't work though.
>
> Sigh, I see, btrfs forces MS_I_VERSION flag,
> 0c4d2d95d06e920e0c61707e62c7fffc9c57f63a. I read 'enabled by default' as
> that there's a standard way to override the defaults.
>
> So the right way is not to do that but this will break everyhing that
> relies on that behaviour at the moment. This means to add the exception
> to the upper layers, either VFS or 'mount', which is not very likely to
> happen.
>
> The generic options do not reach the filesystem specific callbacks, so
> we can't check it.
Ext4 also makes its own "i_version" option, so I think we can do the
same thing until more filesystems require to do it in a generic way.
The performance benefit with no_iversion is obvious for fsync
related workloads since we would avoid some expensive log commits.
Thanks,
-liubo
next prev parent reply other threads:[~2015-06-18 2:46 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-17 7:54 [RFC PATCH v2 1/2] Btrfs: add noi_version option to disable MS_I_VERSION Liu Bo
2015-06-17 7:54 ` [RFC PATCH v2 2/2] Btrfs: improve fsync for nocow file Liu Bo
2015-06-17 15:58 ` David Sterba
2015-06-18 3:27 ` Liu Bo
2015-06-24 18:21 ` David Sterba
2015-06-25 2:24 ` Liu Bo
2015-06-25 16:10 ` David Sterba
2015-06-17 15:33 ` [RFC PATCH v2 1/2] Btrfs: add noi_version option to disable MS_I_VERSION David Sterba
2015-06-17 15:52 ` Liu Bo
2015-06-17 17:01 ` David Sterba
2015-06-18 2:46 ` Liu Bo [this message]
2015-06-18 14:38 ` i_version vs iversion (Was: Re: [RFC PATCH v2 1/2] Btrfs: add noi_version option to disable MS_I_VERSION) David Sterba
2015-06-19 11:44 ` Karel Zak
2015-06-19 11:44 ` Karel Zak
2015-06-22 20:42 ` Dave Chinner
2015-06-22 20:42 ` Dave Chinner
2015-06-24 17:28 ` David Sterba
2015-06-23 16:32 ` Theodore Ts'o
2015-06-24 8:23 ` Liu Bo
2015-06-24 18:02 ` David Sterba
2015-06-24 23:17 ` Theodore Ts'o
2015-06-24 23:17 ` Theodore Ts'o
2015-06-24 23:59 ` Dave Chinner
2015-06-24 23:59 ` Dave Chinner
2015-06-25 18:46 ` J. Bruce Fields
2015-06-25 18:46 ` J. Bruce Fields
2015-06-25 22:12 ` Theodore Ts'o
2015-06-26 13:32 ` J. Bruce Fields
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