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 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
