On Wed, Jun 14, 2023 at 12:12:56PM +0200, Jan Kara wrote: > Well, OK, I have not been precise :). Modifying a partition table (or LVM > description block) is impossible to distinguish from clobbering a > filesystem on open(2) time. Once we decide we implement arbitration of each > individual write(2), we can obviously stop writes to area covered by some > exclusively open partition. But then you are getting at the complexity > level of tracking used ranges of block devices which Darrick has suggested > and you didn't seem to like that (and neither do I). Well, we track these ranges in the block_devices hanging off the gendisk anyway, so this is a totally different league. But in the end parsing partition tables is a little easier than parsing file system metadata but not fundamentally different. So if we really want to lock down broken sideband manipulations we can't allow that either and need in-kernel support for manipulating partition tables if that is required at run time.
