Re: [PATCH 8/9] xfs: add fsgeom flag for v5 superblock support.

Ben Myers
2013-05-29T21:43:02Z

Hi Eric,

On Wed, May 29, 2013 at 10:10:13AM -0500, Eric Sandeen wrote:
> On 5/27/13 1:38 AM, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > Currently userspace has no way of determining that a filesystem is
> > CRC enabled. Add a flag to the XFS_IOC_FSGEOMETRY ioctl output to
> > indicate that the filesystem has v5 superblock support enabled.
> > This will allow xfs_info to correctly report the state of the
> > filesystem.
>
>
> Looks fine,
>
> Reviewed-by: Eric Sandeen <sandeen@redhat.com>
>
> Ben, having this in place for for the next point release will let
> userspace work & testing proceed w/o the need for a patched
> kernel... if you could consider pulling it in that'd be great.

Sounds reasonable. I'll check it out.

> Dave, just out of curiosity, most other features sort of match between
> the "_has_*" and the flag names, is there a reason for the
> crc <-> sbv5 difference? Just semantics, but just curious.
>
> (i.e. xfs_sb_version_hasprojid32bit checks XFS_SB_VERSION2_PROJID32BIT,
> but xfs_sb_version_hascrc checks XFS_SB_VERSION_5)
>
> Answering my own question maybe, I guess SB_VERSION_5 was conceived
> with crc already in place, so there's no need for a feature flag on
> top of the sb version, right...?

Seems like we're also out of space in xfs_fsop_geom.flags. There may even be
people who prefer to use v5 super blocks without crcs turned on, so maybe
conflating the two ideas here is undesireable.

-Ben