Formatting partition with KPMcore

lenatrice · 3 Sept 2025, 01:25

I'm using KPM core to manage partitions, and I was able to successfully implement functions to create partition, delete partition and recreate the partition table. However, when I create the partitions, they are not formatted with any type. When I run lsblk -f or blkid [partition_node], they don't show any type for the newly created partitions. Can someone help me understand what is going wrong?

void PartitionPage::onCreateSystemPartitionsButtonClicked(bool checked)
{
    // Get currently selected Partition pointer and determine it is valid unallocated space for installation.

    Partition* partition = getSelectedPartition();

    if (!partition)
    {
        qWarning() << "Selected Partition is null";
        return;
    }

    if (partition->roles().has(PartitionRole::Unallocated))
    {
        qDebug() << "Selected valid free space for installation";
    } else {
        qWarning() << "Selected partition is not free space";
        return;
    }

    // Get currently selected Device pointer.

    Device* device = getSelectedDevice();

    if (!device)
    {
        qWarning() << "Selected Device is null";
        return;
    }

    // If selected space has less than 10GiB, issue a warning.

    if (static_cast<double>(partition->capacity()) / GiB < 10)
    {
        QMessageBox::StandardButton warningDialog;
        warningDialog = QMessageBox::warning(this, "Attention", "The selected free space of " + getSize(partition) + " may be insufficient to install the system, " + 
        "or may cause problems as more space is required in the future. It's recommended that you select a free space larger than 10GiB.\n\nContinue?", QMessageBox::Ok | QMessageBox::Cancel);

        if (warningDialog == QMessageBox::Cancel) return;
    }

    // Get partition table of the device
    PartitionTable* devicePartitionTable = device->partitionTable();

    // MBR partition table support only 4 primary partitions. Issue an error if it contains more than 2 partitions, as it will not be possible to create the necessary partitions for the system to run.
    if (devicePartitionTable->typeName() == "msdos" && countPrimaryPartitions(device) > 2)
    {
        QMessageBox::StandardButton errorDialog;
        errorDialog = QMessageBox::critical(this, "Error", "MBR partition tables support a maximum of 4 primary partitions, " + 
            QString("and it will not be possible to create the new 2 partitions necessary for the system because you already have ") + QString::number(countPrimaryPartitions(device)) + " partitions in this device." + 
            "Consider deleting existing partitions or select another device.", QMessageBox::Ok
        );
        return;
    }
    
    // Create the filesystems
    qint64 firstBootSector = partition->firstSector();
    qint64 lastBootSector = partition->firstSector() + (MiB * 256) / partition->sectorSize() - 1;
    qint64 firstRootSector = lastBootSector + 1;
    qint64 lastRootSector = partition->lastSector();


    FileSystem* newBootFs = FileSystemFactory::create(FileSystem::Type::Fat32,
        firstBootSector, lastBootSector, device->logicalSize()
    );
        
    FileSystem* newRootFs = FileSystemFactory::create(FileSystem::Type::Ext4,
        firstRootSector, lastRootSector, device->logicalSize()
    );
    
    // Get available flags from the partition table
    PartitionTable::Flags availableFlags;
    for (PartitionTable::Flag _flag : devicePartitionTable->flagList())
    {
        availableFlags |= _flag;
    }

    // Create the partitions
    QString bootDeviceNode = determineNewPartitionNodePath(device->deviceNode(), countPrimaryPartitions(device) + 1);
    QString rootDeviceNode = determineNewPartitionNodePath(device->deviceNode(), countPrimaryPartitions(device) + 2);
    
    Partition* newBootPartition = new Partition(
        devicePartitionTable,                     // PartitionTable
        *device,                                  // Device
        PartitionRole(PartitionRole::Primary),    // Partition Role
        newBootFs,                                // Filesystem 
        firstBootSector, lastBootSector,          // Size of 256 MiB
        bootDeviceNode,                           // Partition node path
        availableFlags,                           // Available flags
        "/mnt/new_root/boot",                     // Mount point
        false,                                    // Not mounted
        PartitionTable::Flag::Boot                // Bootable flag
    );
    
    Partition* newRootPartition = new Partition(
        devicePartitionTable,                     // PartitionTable
        *device,                                  // Device
        PartitionRole(PartitionRole::Primary),    // Partition Role
        newRootFs,                                // Filesystem 
        firstRootSector, lastRootSector,          // Remaining size of the free space [TODO: add option to use less space]
        rootDeviceNode,                           // Partition node path
        availableFlags,                           // Available flags
        "/mnt/new_root/",                         // Mount point
        false,                                    // Not mounted
        PartitionTable::Flag::None                // No flag
    );
    
    // Show an error message if the space is insufficient
    if (newBootPartition->capacity() + newRootPartition->capacity() > partition->capacity())
    {
        QMessageBox::StandardButton errorDialog;
        errorDialog = QMessageBox::critical(this, "Error", "The selected free space is insufficient to install the system.\n"
            + QString("(Space occupied by the new partitions:") + QString::number(static_cast<double>(newBootPartition->capacity() + newRootPartition->capacity()) / GiB) + " GiB)", QMessageBox::Ok
        );
        return;
    }
    
    if (!createBootPartition->canCreateNew(partition))
    {
        qWarning() << "Cannot create new partition";
        return;
    }

    // Set partition type for the new partitions
    if (devicePartitionTable->typeName() == "gpt")
    {
        qDebug() << "Setting partition type for GPT table";
        newBootPartition->setType("C12A7328-F81F-11D2-BA4B-00A0C93EC93B"); // GPT GUID for EFI System Partition
        newRootPartition->setType("0FC63DAF-8483-4772-8E79-3D69D8477DE4"); // GPT GUID for Linux Filesystem
    } else if (devicePartitionTable->typeName() == "msdos") {
        qDebug() << "Setting partition type for MBR table";
        newBootPartition->setType("0xEF"); // MBR type code for EFI System Partition
        newRootPartition->setType("0x83"); // MBR type code for Linux Filesystem
    }

    NewOperation* createBootPartition = new NewOperation(*device, newBootPartition);
    NewOperation* createRootPartition = new NewOperation(*device, newRootPartition);

    qDebug() << "Pushing the operations to create partitions to the operation stack";

    operationStack->push(createBootPartition);
    operationStack->push(createRootPartition);

    runOperations();

    updatePartitionTable();
}

I'm thinking of just running system commands for mkfs.fat -F32 /dev/sdb1 and mkfs.ext4 /dev/sdb2, but it would be good to understand why the filesystems are not correctly formatted so I can understand this library better.

PS: I tried without this before, added this part while trying to solve the problem

   // Set partition type for the new partitions
   if (devicePartitionTable->typeName() == "gpt")
   {
       qDebug() << "Setting partition type for GPT table";
       newBootPartition->setType("C12A7328-F81F-11D2-BA4B-00A0C93EC93B"); // GPT GUID for EFI System Partition
       newRootPartition->setType("0FC63DAF-8483-4772-8E79-3D69D8477DE4"); // GPT GUID for Linux Filesystem
   } else if (devicePartitionTable->typeName() == "msdos") {
       qDebug() << "Setting partition type for MBR table";
       newBootPartition->setType("0xEF"); // MBR type code for EFI System Partition
       newRootPartition->setType("0x83"); // MBR type code for Linux Filesystem
   }

lenatrice · wrote on 9 Mar 2025, 01:41

Found the solution. Added this to the end of the function and now it the partitions filesystems are correctly formatted:

    newBootFs->create(*rootReport, bootDeviceNode);
    newRootFs->create(*rootReport, rootDeviceNode);

Also I could delete this:

    if (devicePartitionTable->typeName() == "gpt")
    {
        qDebug() << "Setting partition type for GPT table";
        newBootPartition->setType("C12A7328-F81F-11D2-BA4B-00A0C93EC93B"); // GPT GUID for EFI System Partition
        newRootPartition->setType("0FC63DAF-8483-4772-8E79-3D69D8477DE4"); // GPT GUID for Linux Filesystem
    } else if (devicePartitionTable->typeName() == "msdos") {
        qDebug() << "Setting partition type for MBR table";
        newBootPartition->setType("0xEF"); // MBR type code for EFI System Partition
        newRootPartition->setType("0x83"); // MBR type code for Linux Filesystem
    }