Hi, Recently I have tested NFS and exportfs scenario, that NFS server and client are in the same host. And I found mounting NFS filesystm onto the same host can lead to rpc.mountd and related task become D state. My kernel version is based on 3.10, and I find 4.15 has the same appearance. My test step as below: 1)create dir. mkdir -p /home/test1 /home/test2 2)share dir /home/test1 echo '/home/test1 localhost(rw,all_squash,anonuid=0,anongid=0)' > /etc/exports 3)exportfs exportfs -vr || echo "Failed to export /home/test1" 4)mount NFS. mount localhost:/home/test1 /home/test2 -o vers=3,soft 5)share dir /home/test2 echo '/home/test2 *(rw,all_squash,anonuid=0,anongid=0)' >> /etc/exports 6)exportfs exportfs -vr 7) list /home/test2 ls /home/test2 then we found ls command is hung, ls and rpc.mountd became "D" state, and after 180 second ls command return. Another scenario as below: 1)create dir. mkdir -p /home/test3 /home/test4 2)share dir /home/test3 echo '/home/test3 localhost(rw,sync,no_wdelay,anonuid=0,anongid=0,no_subtree_check)' > /etc/exports 3)exportfs exportfs -r 4)to see NFS status showmount -e localhost 5)mount NFS mount -t nfs4 -o proto=tcp,nolock,soft,timeo=50 localhost:/home/test3 /home/test4 6) stop nfs service,and and check ls task state is D. service nfs stop ls /home/test4 ls command is hung and became D state. I wonder to know is it reasonable about these test scenario because NFS server and client are in the same host? Since some task went into D state, is there any reason about this? and is there any patch to fix this issue? Here is a link to talk about NFS mounting on the same host, https://lwn.net/Articles/595652/ -- 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
