cifs: check archive is writeable during setup

Permissions problem on the cifs share are a somewhat frequent problem
users run in to, so test that the archive is writeable during setup.

run/cifs_archive/verify-and-configure-archive.sh

@@ -73,7 +73,7 @@ function check_archive_mountable () {
       then
         secopt="sec=$sec"
       fi
-      local commandline="mount -t cifs '//$1/$2' '$test_mount_location' -o 'credentials=${tmp_credentials_file_path},iocharset=utf8,file_mode=0777,dir_mode=0777,$versopt,$secopt'"
+      local commandline="mount -t cifs '//$1/$2' '$test_mount_location' -o '$3,credentials=${tmp_credentials_file_path},iocharset=utf8,file_mode=0777,dir_mode=0777,$versopt,$secopt'"
       log_progress "Trying mount command-line:"
       log_progress "$commandline"
       if eval "$commandline"
@@ -89,6 +89,17 @@ function check_archive_mountable () {
     exit 1
   else
     log_progress "The archive share is mountable using: $commandline"
+    if [ "$3" = "rw" ]
+    then
+       if ! touch "$test_mount_location/testfile"
+       then
+         log_progress "STOP: archive share is not writeable. Check permissions."
+         umount "$test_mount_location"
+         exit 1
+       fi
+       rm "$test_mount_location/testfile"
+    fi
+
     # the music archive must be mountable with the same mount options
     # so fix the options now
     export CIFS_VERSION=$vers
@@ -116,7 +127,7 @@ check_archive_server_reachable
 
 if [ -e /backingfiles/cam_disk.bin ]
 then
-  check_archive_mountable "$ARCHIVE_SERVER" "$SHARE_NAME"
+  check_archive_mountable "$ARCHIVE_SERVER" "$SHARE_NAME" rw
 fi
 
 if [ -n "${MUSIC_SHARE_NAME:+x}" ]
@@ -126,7 +137,7 @@ then
     log_progress "STOP: MUSIC_SHARE_NAME specified but no music drive size specified"
     exit 1
   fi
-  check_archive_mountable "$ARCHIVE_SERVER" "$MUSIC_SHARE_NAME"
+  check_archive_mountable "$ARCHIVE_SERVER" "$MUSIC_SHARE_NAME" ro
 fi
 
 function configure_archive () {
@@ -149,7 +160,7 @@ function configure_archive () {
   if [ -e /backingfiles/cam_disk.bin ]
   then
     local sharenameforstab="${SHARE_NAME// /\\040}"
-    echo "//$ARCHIVE_SERVER/$sharenameforstab $archive_path cifs noauto,credentials=${credentials_file_path},iocharset=utf8,file_mode=0777,dir_mode=0777,$VERS_OPT,$SEC_OPT 0" >> /etc/fstab
+    echo "//$ARCHIVE_SERVER/$sharenameforstab $archive_path cifs rw,noauto,credentials=${credentials_file_path},iocharset=utf8,file_mode=0777,dir_mode=0777,$VERS_OPT,$SEC_OPT 0" >> /etc/fstab
   elif [ -d "$archive_path" ]
   then
     rmdir "$archive_path" || log_progress "failed to remove $archive_path"
@@ -162,7 +173,7 @@ function configure_archive () {
       mkdir "$music_archive_path"
     fi
     local musicsharenameforstab="${MUSIC_SHARE_NAME// /\\040}"
-    echo "//$ARCHIVE_SERVER/$musicsharenameforstab $music_archive_path cifs noauto,credentials=${credentials_file_path},iocharset=utf8,file_mode=0777,dir_mode=0777,$VERS_OPT,$SEC_OPT 0" >> /etc/fstab
+    echo "//$ARCHIVE_SERVER/$musicsharenameforstab $music_archive_path cifs ro,noauto,credentials=${credentials_file_path},iocharset=utf8,file_mode=0777,dir_mode=0777,$VERS_OPT,$SEC_OPT 0" >> /etc/fstab
   elif [ -d "$music_archive_path" ]
   then
     rmdir "$music_archive_path" || log_progress "failed to remove $music_archive_path"