On Wed, Mar 28, 2018 at 4:14 AM, Dai Qizhi <qzdai@xxxxxxxxxxxxxxx> wrote: [...] >> >> > I tested overlayfs with nfs_export feature , the kernel is built by >> > ubuntu , 4.16.0-041600rc7, http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.16-rc7/ >> > >> > the problem is , when i export two different overlay mount points on >> > server side, then mount them use nfs on the client side, the client side >> > views the two differnet mount points as the same. >> > >> > >> > on server side: >> > >> > none on /mnt/m1 type overlay (rw,relatime,lowerdir=m1/ro,upperdir=m1/rw,workdir= >> > m1/w,index=on,nfs_export=on) >> > none on /mnt/m2 type overlay (rw,relatime,lowerdir=m2/ro,upperdir=m2/rw,workdir= >> > m2/w,index=on,nfs_export=on) >> > [root@localhost data]# exportfs -rv >> > exporting *:/mnt/m4 >> > exporting *:/mnt/m3 >> > exporting *:/mnt/m2 >> > exporting *:/mnt/m1 >> > [root@localhost data]# ls /mnt/m1 >> > this_is_m1 >> > [root@localhost data]# ls /mnt/m2 >> > this_is_m2 >> > >> > >> > on client side: >> > >> > [root@localhost mnt]# mount 192.168.0.1:/mnt/m1 m1 >> > [root@localhost mnt]# mount 192.168.0.1:/mnt/m2 m2 >> > [root@localhost mnt]# mount |grep 192 >> > 192.168.0.1:/mnt/m1 on /mnt/m1 type nfs (rw,relatime,vers=3,rsize=524288,wsize=5 >> > 24288,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=192.168.0. >> > 1,mountvers=3,mountport=20048,mountproto=udp,local_lock=none,addr=192.168.0.1) >> > 192.168.0.1:/mnt/m1 on /mnt/m2 type nfs (rw,relatime,vers=3,rsize=524288,wsize=5 >> > 24288,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=192.168.0. >> > 1,mountvers=3,mountport=20048,mountproto=udp,local_lock=none,addr=192.168.0.1) >> > >> > [root@localhost mnt]# ls /mnt/m1 >> > this_is_m1 >> > [root@localhost mnt]# ls /mnt/m2 >> > this_is_m1 >> > [root@localhost mnt]# >> >> >> Please refer to the man page of exports(5), the section about 'fsid' describes >> this problem related to exporting file systems that are not on a block device, >> such as overlayfs. > > yes, export different mount point with different fsid= option works as > expected. > > >> >> If you are interested to know if there is a way to fix this that does >> not involve manually >> configuring different fsid per export, I will have to consult with the >> NFS experts, so please >> reply to this message with CC to <linux-unionfs@xxxxxxxxxxxxxxx> and >> <linux-nfs@xxxxxxxxxxxxxxx> > > when exporting parent directory with crossmnt option and mount differnet overlayfs > under that directory, we encounter the same problem on client side.. > I see. Jeff, Bruce, is there a school book solution to this issue? Is there a way for a non blockdev export to automatically identify itself to knfsd? After all, the tuple ("overlayfs";<overlay root file handle>) should be unique on the server. <overlay root file handle> contains (struct ovl_fh) the upper fs UUID and the upper root dir file handle. Technically, if there is no out of tree fs on the system that is using the value OVL_FILEID (0xfb) for file handle type <overlay root file handle> itself would be unique. Thanks, Amir. -- 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
