diff --git a/src/libcalamares/partition/Tests.cpp b/src/libcalamares/partition/Tests.cpp
index a456d7e36..16f7d78c2 100644
--- a/src/libcalamares/partition/Tests.cpp
+++ b/src/libcalamares/partition/Tests.cpp
@@ -209,6 +209,13 @@ PartitionServiceTests::testFilesystemGS()
     useFilesystemGS( &gs, "EXT4", false );
     QVERIFY( !isFilesystemUsedGS( &gs, "EXT4" ) );
     QCOMPARE( isFilesystemUsedGS( &gs, "EXT4" ), isFilesystemUsedGS( &gs, "ext4" ) );
+    useFilesystemGS( &gs, "ext4", true );
+    QVERIFY( isFilesystemUsedGS( &gs, "EXT4" ) );
+
+    CalamaresUtils::Partition::clearFilesystemGS( &gs );
+    QVERIFY( !isFilesystemUsedGS( &gs, "ZFS" ) );
+    QVERIFY( !isFilesystemUsedGS( &gs, "EXT4" ) );
+    QVERIFY( !isFilesystemUsedGS( &gs, "ext4" ) );
 }
 
 
diff --git a/src/modules/partition/jobs/FillGlobalStorageJob.cpp b/src/modules/partition/jobs/FillGlobalStorageJob.cpp
index 1660dbb54..f79918e64 100644
--- a/src/modules/partition/jobs/FillGlobalStorageJob.cpp
+++ b/src/modules/partition/jobs/FillGlobalStorageJob.cpp
@@ -18,6 +18,7 @@
 #include "GlobalStorage.h"
 #include "JobQueue.h"
 #include "partition/FileSystem.h"
+#include "partition/Global.h"
 #include "partition/PartitionIterator.h"
 #include "utils/Logger.h"
 
@@ -291,35 +292,29 @@ FillGlobalStorageJob::prettyStatusMessage() const
  * .. mark as "1" if it's on the system, somewhere
  * .. mark as "2" if it's one of the claimed / in-use FSses
  *
- * Stores a GS key called "filesystems_use" with this mapping.
+ * Stores a GS key called "filesystem_use" with this mapping.
+ * @see CalamaresUtils::Partition::useFilesystemGS()
  */
 static void
 storeFSUse( Calamares::GlobalStorage* storage, const QVariantList& partitions )
 {
-    QMap< QString, int > fsUses;
-    for ( const auto& p : partitions )
+    if ( storage )
     {
-        const auto pmap = p.toMap();
-
-        QString fs = pmap.value( "fs" ).toString();
-        int thisUse = pmap.value( "claimed" ).toBool() ? 2 : 1;
-
-        if ( fs.isEmpty() )
+        CalamaresUtils::Partition::clearFilesystemGS( storage );
+        for ( const auto& p : partitions )
         {
-            continue;
+            const auto pmap = p.toMap();
+
+            QString fs = pmap.value( "fs" ).toString();
+
+            if ( fs.isEmpty() )
+            {
+                continue;
+            }
+
+            CalamaresUtils::Partition::useFilesystemGS( storage, fs, true );
         }
-
-        int newUse = qMax( fsUses.value( fs ), thisUse );  // value() is 0 if not present
-        fsUses.insert( fs, newUse );
     }
-
-    QVariantMap fsUsesVariant;
-    for ( auto it = fsUses.cbegin(); it != fsUses.cend(); ++it )
-    {
-        fsUsesVariant.insert( it.key(), it.value() );
-    }
-
-    storage->insert( "filesystems_use", fsUsesVariant );
 }
 
 Calamares::JobResult