On Thu, Jul 25, 2024 at 05:41:54PM -0700, Darrick J. Wong wrote: > On Fri, Jul 26, 2024 at 08:33:02AM +1000, Dave Chinner wrote: > > On Thu, Jul 25, 2024 at 04:14:13PM +0200, Christoph Hellwig wrote: > > > On Thu, Jul 25, 2024 at 12:05:26PM +1000, Dave Chinner wrote: > > > > Maybe I'm missing something important - this doesn't feel like > > > > on-disk format stuff. Why would having online repair enabled make > > > > the fileystem unmountable on older kernels? > > > > > > Yes, that's the downside of the feature flag. > > > > > > > Hmmm. Could this be implemented with an xattr on the root inode > > > > that says "self healing allowed"? > > > > > > The annoying thing about stuff in the public file system namespace > > > is that chowning the root of a file system to a random user isn't > > > that uncommon, an that would give that user more privileges than > > > intended. So it could not hust be a normal xattr but would have > > > to be a privileged one, > > > > > > I'm not sure I understand what the problem is. We have a generic > > xattr namespace for this sort of userspace sysadmin info already. > > > > $ man 7 xattr > > .... > > Trusted extended attributes > > Trusted extended attributes are visible and accessible only > > to processes that have the CAP_SYS_ADMIN capability. > > Attributes in this class are used to implement mechanisms > > in user space (i.e., outside the kernel) which keep > > information in extended attributes to which ordinary > > processes should not have access. > > > > > and with my VFS hat on I'd really like > > > to avoid creating all these toally overloaded random non-user > > > namespace xattrs that are a complete mess. > > > > There's no need to create a new xattr namespace at all here. > > Userspace could manipulate a trusted.xfs.self_healing xattr to do > > exactly what we need. It's automatically protected by > > CAP_SYS_ADMIN in the init namespace, hence it provides all the > > requirements that have been presented so far... > > <nod> Ok, how about an ATTR_ROOT xattr "xfs.self_healing" that can be > one of "none", "check", or "repair". No xattr means "check". Sounds good to me. -Dave. -- Dave Chinner david@xxxxxxxxxxxxx
