2015-10-20 10:40 GMT+02:00 Prunk Dump <prunkdump@xxxxxxxxx>: > 2015-10-19 14:09 GMT+02:00 Prunk Dump <prunkdump@xxxxxxxxx>: >> Hello NFS team ! >> >> I have sometimes trouble using NFSv4 referrals and I don't really >> understand where the problem come from. Here the configuration steps >> that expose the situation : >> >> --------------------------------------------- >> 1) standard nfs4 export (works) >> --------------------------------------------- >> My server export a file tree like this : >> >> /myexport/dirA >> /myexport/dirB >> >> To do this I have bind mounted as usual the tree root in the NFS root : >> >> mount --bind /myexport /srv/nfs4/myexport >> /srv/nfs4/myexport >> 172.16.0.0/16(sec=krb5,rw,async,no_subtree_check) (in /etc/exports) >> >> Everything is OK. >> >> ----------------------------------------------------------------- >> 2) dirA redirection, bind mounted to itself (works) >> ----------------------------------------------------------------- >> >> I now want to redirect dirA to another server "anotherserver". So I >> bind mount the dirA folder to itself. >> >> mount --bind /srv/nfs4/myexport/dirA /srv/nfs4/myexport/dirA >> /srv/nfs4/myexport/dirA >> 172.16.0.0/16(refer=/myexport/dirA@anotherserver,sec=krb5,rw,async,no_subtree_check) >> (in /etc/exports) >> >> Now the redirection works as expected. >> >> ---------------------------------------------------------------------------------- >> 3) mount remote dirA on the original server (first problem) >> ----------------------------------------------------------------------------------- >> >> But the original server need to keep access to the "dirA" files. So I >> need to mount the redirected "dirA@anotherserver" tree on "myserver". >> >> mount -t nfs4 -o sec=krb5 anotherserver:/myexport/dirA /myexport/dirA >> >> But as /myexport is bind mounted, this command create another mount >> point on /srv/nfs4/myexport/dirA. >> >> # mount >> ... >> anotherserver:/myexport/dirA on /myexport/dirA ... >> anotherserver:/myexport/dirA on /srv/nfs4/myexport/dirA ... >> >> So, as this command create a mount point at the right position, where >> the redirection start, I initially think that the initial self binded >> mount /srv/nfs4/myexport/dirA is useless now. So I keep the only the >> nfs4 mount. >> >> But strangely the redirection does not works anymore. And I don't >> understand where is the problem. >> >> ###### >> first solution tried : mount remote to /myexport/dirA, adding an >> additional bind mount (don't works) >> ###### >> >> I tried to add another bind mount over the nfs mount. I now have four >> mount points ! >> >> anotherserver:/myexport/dirA on /myexport/dirA ... >> anotherserver:/myexport/dirA on /srv/nfs4/myexport/dirA ... >> anotherserver:/myexport/dirA on /srv/nfs4/myexport/dirA ... >> anotherserver:/myexport/dirA on /myexport/dirA ... >> >> But this does not solve the problem. No redirection. >> >> ###### >> second solution tried : mount remote nfs directly to >> /srv/nfs4/myexport/dirA (works !) >> ###### >> >> If a mount the remote share directly to /srv/nfs4/myexport/dirA : >> >> mount -t nfs4 -o sec=krb5 anotherserver:/myexport/dirA /srv/nfs4/myexport/dirA >> >> as /myexport is bind mounted, this create another mount point on >> /myexport/dirA : >> >> # mount >> anotherserver:/myexport/dirA on /srv/nfs4/myexport/dirA ... >> anotherserver:/myexport/dirA on /myexport/dirA ... >> >> But the mount points are in reverse order now. And in this case it >> works ! I can access the remote share in /myexport/dirA. And the other >> clients are redirected to anotherserver. >> >> But I can't understand why... >> >> Why the mount order is so important ? >> >> Thanks ! >> >> Baptiste. > > Excuse me ! > > In reality the solution proposed above does not work ! The NFS server > say : "/myexport/dirA does not support NFS export" as it is a NFS > mounted filesystem. > > Can anyone help me !? > > Is this possible to avoid duplicating mount point when mounting over > bind mount ? > > /myexport and /srv/nfs4/myexport are the same mount. But I want to do > a nfs4 mount on /myexpot/dirA and a bind mount on > /srv/nfs4/myexport/dirA. > > Thanks. > > Baptiste. I finally found a working solution. I have added the "private" option on the initial /srv/nfs4/myexport bind mount. So now the subtree mounts are not duplicated. I can bind mount /srv/nfs4/myexport/dirA to itself I can mount the remote nfs4 share on /myexport/dirA But I would be nice if the redirection can works with an nfs4 mount point even if an nfs4 filesystem can't be exported by an nfs4 server. Baptiste. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
