Re: [LSF/MM ATTEND] Attendance request

[David Sterba <dsterba@suse.cz>]

On Fri, Mar 04, 2016 at 08:59:06AM -0800, Liu Bo wrote:
> On Fri, Mar 04, 2016 at 08:53:15AM -0800, Liu Bo wrote:
> > On Fri, Mar 04, 2016 at 03:30:58PM +0100, David Sterba wrote:
> > > On Sun, Feb 28, 2016 at 03:16:15PM -0800, Liu Bo wrote:
> > > > Hi,
> > > > 
> > > > I'd like to attend the LSF/MM conference this year.
> > > > 
> > > > I think I can contribute to a few areas that are being discussed this year:
> > > >   - how to provide better information for the filesystem to optimize allocation.
> > > >   - power/failure tests
> > > >   - performance aspects, etc.
> > > > 
> > > > Besides that, I'd like to talk about the following,
> > > >   - combining overlayfs with btrfs to properly fix overlayfs copy-up slowness.
> > > >   - fragmentation control in Copy-On-Write filesystems. (setting a reasonable
> > > >     large allocation unit and performing RMW, etc?)
> > > >     Since xfs is also going to have reflink, so xfs is also regarded as COW
> > > >     FS, having some generic ideas for this topic would help a lot.
> > > >   - mount individual subvolumes (in btrfs) with different selinux label, this
> > > >     will be useful in container senarios when btrfs being their storage driver.
> > > > 
> > > > (I've finished the patch for the above selinux label support, but it can ends up
> > > > with inode leak if it's not used in the container way, which is assuming the
> > > > top subvolume is always being the last one to unmout.)
> > > 
> > > Do you have the patchset so I can have a look? I've claimed the
> > > per-subvolume mount properties in the past and have it almost working.
> > > Supporting selinux labels seems to have some overlap, so I'm curious how
> > > much code conflicts are there.
> > 
> > There might be some conflicts since I'm using pseudo superblock for each
> > subvolume in that case in order to support selinux label.
> 
> I also changed docker's btrfs graphdriver code to mount a
> subvolume/snapshot like what devicemapper does so that it can have
> different selinux label for each container.
> 
> To test it, we have to use "mount -osubvolid=AAA,nosharecache=AAA /disk /mnt"

Thanks. Code-wise there are no conflicts but my implementation does not
expect existence of the extra superblocks so it would not work together.