On Mon, Feb 12, 2024 at 05:47:40PM -0500, Theodore Ts'o wrote: > On Wed, Feb 07, 2024 at 03:26:55PM -0500, Kent Overstreet wrote: > > You've still got the ext4 version, we're not taking that away. But I > > don't think other filesystems will want to deal with the hassle of > > changing UUIDs at runtime, since that's effectively used for API access > > via sysfs and debugfs. > > Thanks. I misunderstood the log. I didn't realize this was just about > not hoisting the ioctl to the VFS level, and dropping the generic uuid > set. > > I'm not convinced that we should be using the UUID for kernel API > access, if for no other reason that not all file systems have UUID's. > Sure, modern file systems have UUID's, and individual file systems > might have to have specific features that don't play well with UUID's > changing while the file system is mounted. But I'm hoping that we > don't add any new interfaces that rely on using the UUID for API > access at the VFS layer. After all, ext2 (not just ext3 and ext4) has > supported changing the UUID while the file system has been mounted for > *decades*. *nod* The intention isn't for every filesystem to be using the UUID for API access - there's no reason to for single device filesystems, after all. The intent is rather - for filesystems that _do_ need the UUID as a stable identifier, let's try to standardize how's it's exposed and used...
