Kernel/Devices: Defer creation of SysFS component after the constructor

Instead of doing so in the constructor, let's do immediately after the
constructor, so we can safely pass a reference of a Device, so the
SysFSDeviceComponent constructor can use that object to identify whether
it's a block device or a character device.
This allows to us to not hold a device in SysFSDeviceComponent with a
RefPtr.
Also, we also call the before_removing method in both SlavePTY::unref
and File::unref, so because Device has that method being overrided, it
can ensure the device is removed always cleanly.

2 files changed, 7 insertions, 3 deletions

diff --git a/Kernel/Storage/Partition/DiskPartition.cpp b/Kernel/Storage/Partition/DiskPartition.cpp
index 17d474f011..5352528773 100644
--- a/Kernel/Storage/Partition/DiskPartition.cpp
+++ b/Kernel/Storage/Partition/DiskPartition.cpp
@@ -12,7 +12,10 @@ namespace Kernel {
 
 NonnullRefPtr<DiskPartition> DiskPartition::create(BlockDevice& device, unsigned minor_number, DiskPartitionMetadata metadata)
 {
-    return adopt_ref(*new DiskPartition(device, minor_number, metadata));
+    auto partition_or_error = try_create_device<DiskPartition>(device, minor_number, metadata);
+    // FIXME: Find a way to propagate errors
+    VERIFY(!partition_or_error.is_error());
+    return partition_or_error.release_value();
 }
 
 DiskPartition::DiskPartition(BlockDevice& device, unsigned minor_number, DiskPartitionMetadata metadata)
diff --git a/Kernel/Storage/Partition/DiskPartition.h b/Kernel/Storage/Partition/DiskPartition.h
index 46f99a1fcd..1d4bae1c75 100644
--- a/Kernel/Storage/Partition/DiskPartition.h
+++ b/Kernel/Storage/Partition/DiskPartition.h
@@ -28,11 +28,12 @@ public:
 
     const DiskPartitionMetadata& metadata() const;
 
+    // FIXME: We expose this constructor to make try_create_device helper to work
+    DiskPartition(BlockDevice&, unsigned, DiskPartitionMetadata);
+
 private:
     virtual StringView class_name() const override;
 
-    DiskPartition(BlockDevice&, unsigned, DiskPartitionMetadata);
-
     WeakPtr<BlockDevice> m_device;
     DiskPartitionMetadata m_metadata;
 };