[RFC PATCHSET] xfsprogs: filesystem properties

["Darrick J. Wong" <djwong@kernel.org>]

Hi all,

After last week's discussion about how to allow sysadmins to opt in or
out of autonomous self healing XFS[1], I now have an RFC patchset that
implements the filesystem properties that we talked about.

As a refresher, the design I settled on is to add ATTR_ROOT (aka
"trusted") xattrs to the root directory.  ATTR_ROOT xattrs can only be
accessed by processes with CAP_SYS_ADMIN, so unprivileged userspace
can't mess with the sysadmin's configured preferences.

I decided that all fs properties should have "xfs:" in the name to make
them look distinct, and defined "trusted.xfs:self_healing" as the
property that controls the amount of autonomous self healing.  There's a
new wrapper program "xfs_property" that one can use to administer the
properties.  xfs_scrub{,bed} uses the property; and mkfs.xfs can set it
for you at format time.

# mkfs.xfs -m self_healing /dev/sda

# xfs_property /dev/sda get self_healing
repair

# mount /dev/sda /mnt

# xfs_property /mnt set self_healing=check

# xfs_scrub -o fsprops_advise /mnt
Info: /mnt: Checking per self_healing directive.

--D

[1] https://lore.kernel.org/linux-xfs/20240724213852.GA612460@frogsfrogsfrogs/