diff --git a/src/core/operationstack.cpp b/src/core/operationstack.cpp
index b1a6d9d..d95e847 100644
--- a/src/core/operationstack.cpp
+++ b/src/core/operationstack.cpp
@@ -456,7 +456,7 @@ void OperationStack::clearOperations()
         Operation* o = operations().takeLast();
         if (o->status() == Operation::StatusPending)
             o->undo();
-        delete o;
+        o->deleteLater();
     }
 
     emit operationsChanged();
diff --git a/src/core/partition.cpp b/src/core/partition.cpp
index 5c8c200..d756621 100644
--- a/src/core/partition.cpp
+++ b/src/core/partition.cpp
@@ -80,7 +80,8 @@ Partition::~Partition()
     // list of children). As a workaround, always remove a partition from its parent here in the dtor.
     // This presumably fixes 232092, but backporting is too risky until we're sure this doesn't cause
     // side-effects.
-    parent()->remove(this);
+    if (m_Parent)
+        parent()->remove(this);
     clearChildren();
     deleteFileSystem();
 }
diff --git a/src/core/partition.h b/src/core/partition.h
index 0464f37..bbda5a3 100644
--- a/src/core/partition.h
+++ b/src/core/partition.h
@@ -27,6 +27,7 @@
 
 #include <QStringList>
 #include <QtGlobal>
+#include <QPointer>
 
 class Device;
 class OperationStack;
@@ -270,7 +271,7 @@ private:
 
     qint32 m_Number;
     Partitions m_Children;
-    PartitionNode* m_Parent;
+    QPointer< PartitionNode > m_Parent;
     FileSystem* m_FileSystem;
     PartitionRole m_Roles;
     qint64 m_FirstSector;
diff --git a/src/fs/btrfs.cpp b/src/fs/btrfs.cpp
index c27472a..00ed17f 100644
--- a/src/fs/btrfs.cpp
+++ b/src/fs/btrfs.cpp
@@ -53,7 +53,7 @@ void btrfs::init()
     m_Create = findExternal(QStringLiteral("mkfs.btrfs")) ? cmdSupportFileSystem : cmdSupportNone;
     m_Check = findExternal(QStringLiteral("btrfsck"), QStringList(), 1) ? cmdSupportFileSystem : cmdSupportNone;
     m_Grow = (m_Check != cmdSupportNone && findExternal(QStringLiteral("btrfs"))) ? cmdSupportFileSystem : cmdSupportNone;
-    m_GetUsed = findExternal(QStringLiteral("btrfs-debug-tree")) ? cmdSupportFileSystem : cmdSupportNone;
+    m_GetUsed = findExternal(QStringLiteral("btrfs")) ? cmdSupportFileSystem : cmdSupportNone;
     m_Shrink = (m_Grow != cmdSupportNone && m_GetUsed != cmdSupportNone) ? cmdSupportFileSystem : cmdSupportNone;
 
     m_SetLabel = findExternal(QStringLiteral("btrfs")) ? cmdSupportFileSystem : cmdSupportNone;
@@ -91,7 +91,7 @@ FileSystem::SupportTool btrfs::supportToolName() const
 
 qint64 btrfs::minCapacity() const
 {
-    return 256 * Capacity::unitFactor(Capacity::Byte, Capacity::MiB);
+    return 40 * Capacity::unitFactor(Capacity::Byte, Capacity::MiB);
 }
 
 qint64 btrfs::maxCapacity() const
diff --git a/src/fs/f2fs.cpp b/src/fs/f2fs.cpp
index 634e75d..c56e045 100644
--- a/src/fs/f2fs.cpp
+++ b/src/fs/f2fs.cpp
@@ -94,7 +94,7 @@ FileSystem::SupportTool f2fs::supportToolName() const
 
 qint64 f2fs::minCapacity() const
 {
-    return 128 * Capacity::unitFactor(Capacity::Byte, Capacity::MiB); // FIXME
+    return 30 * Capacity::unitFactor(Capacity::Byte, Capacity::MiB);
 }
 
 qint64 f2fs::maxCapacity() const
diff --git a/src/fs/nilfs2.cpp b/src/fs/nilfs2.cpp
index 38da68f..2a7a05f 100644
--- a/src/fs/nilfs2.cpp
+++ b/src/fs/nilfs2.cpp
@@ -59,7 +59,7 @@ void nilfs2::init()
     m_SetLabel = findExternal(QStringLiteral("nilfs-tune")) ? cmdSupportFileSystem : cmdSupportNone;
     m_UpdateUUID = findExternal(QStringLiteral("nilfs-tune")) ? cmdSupportFileSystem : cmdSupportNone;
 
-    m_Grow = (m_Check != cmdSupportNone && findExternal(QStringLiteral("nilfs-resize"))) ? cmdSupportFileSystem : cmdSupportNone;
+    m_Grow = findExternal(QStringLiteral("nilfs-resize")) ? cmdSupportFileSystem : cmdSupportNone;
     m_GetUsed = findExternal(QStringLiteral("nilfs-tune")) ? cmdSupportFileSystem : cmdSupportNone;
     m_Shrink = (m_Grow != cmdSupportNone && m_GetUsed != cmdSupportNone) ? cmdSupportFileSystem : cmdSupportNone;
 
diff --git a/src/fs/ntfs.cpp b/src/fs/ntfs.cpp
index 80f512a..9ee775d 100644
--- a/src/fs/ntfs.cpp
+++ b/src/fs/ntfs.cpp
@@ -176,27 +176,9 @@ bool ntfs::resize(Report& report, const QString& deviceNode, qint64 length) cons
 bool ntfs::updateUUID(Report& report, const QString& deviceNode) const
 {
     Q_UNUSED(report);
-    QUuid uuid = QUuid::createUuid();
-    char* s = reinterpret_cast<char*>(&uuid.data4[0]);
+    ExternalCommand cmd(QStringLiteral("ntfslabel"), { QStringLiteral("--new-serial"), deviceNode });
 
-    QFile device(deviceNode);
-    if (!device.open(QFile::ReadWrite | QFile::Unbuffered)) {
-        Log() << xi18nc("@info/plain", "Could not open partition <filename>%1</filename> for writing when trying to update the NTFS serial number.", deviceNode);
-        return false;
-    }
-
-    if (!device.seek(0x48)) {
-        Log() << xi18nc("@info/plain", "Could not seek to position 0x48 on partition <filename>%1</filename> when trying to update the NTFS serial number.", deviceNode);
-        return false;
-    }
-
-    if (device.write(s, 8) != 8) {
-        Log() << xi18nc("@info/plain", "Could not write new NTFS serial number to partition <filename>%1</filename>.", deviceNode);
-        return false;
-    }
-
-    Log() << xi18nc("@info/plain", "Updated NTFS serial number for partition <filename>%1</filename> successfully.", deviceNode);
-    return true;
+    return cmd.run(-1) && cmd.exitCode() == 0;
 }
 
 bool ntfs::updateBootSector(Report& report, const QString& deviceNode) const
diff --git a/src/gui/partwidgetbase.cpp b/src/gui/partwidgetbase.cpp
index 05f5814..544b047 100644
--- a/src/gui/partwidgetbase.cpp
+++ b/src/gui/partwidgetbase.cpp
@@ -32,7 +32,7 @@ T sum(const QList<T>& list)
 {
     T rval = 0;
     foreach(const T & val, list)
-    rval += val;
+        rval += val;
     return rval;
 }