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*. - Ted