On Sat, Dec 21, 2019 at 10:16:52AM +0000, Chris Down wrote: > Darrick J. Wong writes: > >On Fri, Dec 20, 2019 at 02:49:36AM +0000, Chris Down wrote: > >>In general, userspace applications expect that (device, inodenum) should > >>be enough to be uniquely point to one inode, which seems fair enough. > > > >Except that it's not. (dev, inum, generation) uniquely points to an > >instance of an inode from creation to the last unlink. I thought that (dev, inum) was supposed to be unique from creation to last unlink (and last close), and (dev, inum, generation) was supposed to be unique for all time. > I didn't mention generation because, even though it's set on tmpfs > (to prandom_u32()), it's not possible to evaluate it from userspace > since `ioctl` returns ENOTTY. We can't ask userspace applications to > introspect on an inode attribute that they can't even access :-) Is there any reason not to add IOC_GETVERSION support to tmpfs? I wonder if statx should return it too? --b.
