Re: [PATCH v1] xfs_spaceman: add fsuuid command

[Dave Chinner <david@fromorbit.com>]

On Wed, Nov 09, 2022 at 02:23:35PM -0800, Catherine Hoang wrote:
> Add support for the fsuuid command to retrieve the UUID of a mounted
> filesystem.
> 
> Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>

Not looking at the code, just the high level CLI interface issues.

That is, xfs_admin already has user interfaces to get/set the
filesystem UUID on XFS filesystems. Further, xfs_spaceman is for XFS
filesystem SPACE MANagement, not filesystem identification
operations.

xfs_admin is CLI interface that aggregates various admin utilities
such as identification (UUID and label) management.  If we need to
implement a generic VFS ioctl for online UUID retreival, xfs_io is
generally the place to put it because then it can be used by fstests
to run on other filesytems.

We can then wrap xfs_admin around the xfs_io command as needed. i.e.
use 'xfs_io -c fsuuid /mnt/pt' if the filesystem is mounted, 'xfs_db
-c uuid /path/to/device' if the filesystem is not mounted, and we
can make sure that both the xfs_db and xfs_io commands have the same
output....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com