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, 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. One option would be an xattr on the metadir root (once we merge that, hopefully for 6.12). That would still require a new ioctl or whatever interface to change (or carve out an exception to the attr by handle interface), but it would not require kernel and tools to fully understand it. > > Note that administrator-initated scans (e.g. invoking xfs_scrub from the > > CLI) would not be blocked by this flag. > > > > Question: Should this compat flag control background scrubs as well? > > Probably. scrub is less intrusive, but I can see people wanting to > avoid it because it can have a perf impact. Could this be done with > a different xattr on the root inode? Yes, scrub vs repair should probably be separate.
