Fix root access to VitastorFS files

tests/test_nfs.sh

@@ -13,6 +13,12 @@ sudo mount localhost:/ ./testdata/nfs -o port=2050,mountport=2050,nfsvers=3,soft
 MNT=$(pwd)/testdata/nfs
 trap "sudo umount -f $MNT"' || true; kill -9 $(jobs -p)' EXIT
 
+touch ./testdata/nfs/f1
+chown 1000:1000 ./testdata/nfs/f1
+chmod 600 ./testdata/nfs/f1
+sudo cat ./testdata/nfs/f1
+rm ./testdata/nfs/f1
+
 # write small file
 ls -l ./testdata/nfs
 dd if=/dev/urandom of=./testdata/f1 bs=100k count=1