display used space in loop & code cleanup

usr/share/rear/conf/default.conf

@@ -2182,7 +2182,7 @@ COPY_AS_IS_EXCLUDE_NBKDC=()
 REQUIRED_PROGS_NFS4SERVER=("rpc.nfsd" "rpc.mountd" "exportfs" "ss" "nproc")
 NFS4SERVER_MODULES=(nfs nfsd)
 # List of share options for the recovery system, see 'General Options' in exports(5)
-NFS4SERVER_EXPORT_OPTS=("rw" "no_root_squash" "async" "no_subtree_check")
+NFS4SERVER_EXPORT_OPTS=(rw no_root_squash async no_subtree_check)
 # List of trusted systems that can mount the recovery system, see 'Machine Name Formats' in exports(5)
 # e.g. NFS4SERVER_TRUSTED_CLIENTS=( myserver 172.16.76.0/24 )
 NFS4SERVER_TRUSTED_CLIENTS=()

usr/share/rear/restore/NFS4SERVER/default/300_start_nfs_server.sh

@@ -2,7 +2,8 @@
 
 # same options works for mountd
 local nfsd_opts=(--no-udp --no-nfs-version 3 -V 4.2)
-local cpu_cores=$(nproc)
+local cpu_cores
+cpu_cores=$(nproc) || Error "Could not determine CPU details via nproc"
 # 4 threads per cpu core
 local nfs_threads=$(( $cpu_cores * 4 ))
 # 8 are the standard and should be the minumun

usr/share/rear/restore/NFS4SERVER/default/400_restore_with_nfs_server.sh

@@ -12,6 +12,10 @@ LogPrint "Wait until $check_file was created and there is no connection on the N
 # or look at /var/lib/nfs/rmtab
 local nfs_connections=1
 while [ ! -f "$check_file" ] || [ "$nfs_connections" -gt 0 ]; do
+    local available_size
+    available_size=$(df --total --local -h --exclude-type=tmpfs --exclude-type=devtmpf | tail -n 1 | awk '{print $3}') &&
+        ProgressInfo "      Used storage space: $available_size"
+
     sleep 5
     nfs_connections=$(ss -tanpH state established "( sport = 2049 )" | wc -l)
 done

usr/share/rear/verify/NFS4SERVER/default/400_verify_nfs_server.sh

@@ -0,0 +1,4 @@
+# 400_verify_nfs_server.sh
+
+# Check if at least one trusted client was specified
+(( "${#NFS4SERVER_TRUSTED_CLIENTS[@]}" > 0 )) || Error "You must have defined at least one client in NFS4SERVER_TRUSTED_CLIENTS."