On Mon, Sep 16, 2019 at 3:25 PM <lange@xxxxxxxxxx> wrote: > > Hi, > > I'm using overlayfs with NFS v3 as a lower (mounted read-only) and a > tmpfs as an upper filesystem. This works nicely since several years. > So I get a writeable directory tree on an nfs client even the nfs was > mounted ro. > > But then I mount the lower filesystem as NFS v4 (4.2) it does not > work. Is this combination supposed to work? > I tested this with kernels up to 5.2 yet but still no success. > > > Here's my current test setup: > > NFS server kernel 5.2.0-0.bpo.2-amd64 (Debian 10 with newer kernel) > NFS client kernel 5.2.0-0.bpo.2-amd64 (Debian 10 with newer kernel) > > On the NFS server I did once > # mkdir /files/scratch/t/etc; echo test-buster > /files/scratch/t/etc/test1 > > /etc/exports: /files/scratch 11.22.33.128/25(async,ro,no_subtree_check,no_root_squash) > > I can do more tests if you tell me what I can change. > Here are the two tests result, one using nfs v3 the other using NFS v4. > > P.S.: After more research I think this may be a problem of a > filesystem missing xattr support. Do you have any experiences > using overlayfs using NFS v4 as lower fs? This is most probably about nfs4 acl support. Does "noacl" export option fix it? Thanks, Miklos >
