On Sat, Aug 11, 2018 at 02:58:15AM +0100, Al Viro wrote: > On Fri, Aug 10, 2018 at 08:05:44PM -0500, Eric W. Biederman wrote: > > > All I proposed was that we distinguish between a first mount and an > > additional mount so that userspace knows the options will be ignored. > > For pity sake, just what does it take to explain to you that your > notions of "first mount" and "additional mount" ARE HEAVILY FS-DEPENDENT > and may depend upon the pieces of state userland (especially in container) > simply does not have? > > One more time, slowly: > > mount -t nfs4 wank.example.org:/foo/bar /mnt/a > mount -t nfs4 wank.example.org:/baz/barf /mnt/b > > yield the same superblock. Is anyone who mounts something over NFS > required to know if anybody else has mounted something from the same > server, and if so how the hell are they supposed to find that out, > so that they could decide whether they are creating the "first" or > "additional" mount, whatever that might mean in this situation? > > And how, kernel-side, is that supposed to be handled by generic code > of any description? > > While we are at it, > mount -t nfs4 wank.example.org:/foo/bar -o wsize=16384 /mnt/c > is *NOT* the same superblock as the previous two. s/as the previous two/as in the previous two cases/, that is - the first two examples yield one superblock, this one - another.
