Kernel: Split VMObject into two classes: Anonymous- and InodeVMObject

InodeVMObject is a VMObject with an underlying Inode in the filesystem.
AnonymousVMObject has no Inode.

I'm happy that InodeVMObject::inode() can now return Inode& instead of
VMObject::inode() return Inode*. :^)

Kernel/VM/VMObject.cpp

@@ -3,166 +3,22 @@
 #include <Kernel/VM/MemoryManager.h>
 #include <Kernel/VM/VMObject.h>
 
-NonnullRefPtr<VMObject> VMObject::create_file_backed(RefPtr<Inode>&& inode)
-{
-    InterruptDisabler disabler;
-    if (inode->vmo())
-        return *inode->vmo();
-    auto vmo = adopt(*new VMObject(move(inode)));
-    vmo->inode()->set_vmo(*vmo);
-    return vmo;
-}
-
-NonnullRefPtr<VMObject> VMObject::create_anonymous(size_t size)
-{
-    size = ceil_div(size, PAGE_SIZE) * PAGE_SIZE;
-    return adopt(*new VMObject(size));
-}
-
-NonnullRefPtr<VMObject> VMObject::create_for_physical_range(PhysicalAddress paddr, size_t size)
-{
-    size = ceil_div(size, PAGE_SIZE) * PAGE_SIZE;
-    return adopt(*new VMObject(paddr, size));
-}
-
-NonnullRefPtr<VMObject> VMObject::clone()
-{
-    return adopt(*new VMObject(*this));
-}
-
-VMObject::VMObject(VMObject& other)
-    : m_inode_offset(other.m_inode_offset)
-    , m_size(other.m_size)
-    , m_inode(other.m_inode)
+VMObject::VMObject(const VMObject& other)
+    : m_size(other.m_size)
     , m_physical_pages(other.m_physical_pages)
 {
     MM.register_vmo(*this);
 }
 
-VMObject::VMObject(size_t size)
+VMObject::VMObject(size_t size, ShouldFillPhysicalPages should_fill_physical_pages)
     : m_size(size)
 {
     MM.register_vmo(*this);
-    m_physical_pages.resize(page_count());
-}
-
-VMObject::VMObject(PhysicalAddress paddr, size_t size)
-    : m_size(size)
-{
-    MM.register_vmo(*this);
-    for (size_t i = 0; i < size; i += PAGE_SIZE) {
-        m_physical_pages.append(PhysicalPage::create(paddr.offset(i), false, false));
-    }
-    ASSERT(m_physical_pages.size() == page_count());
-}
-
-VMObject::VMObject(RefPtr<Inode>&& inode)
-    : m_inode(move(inode))
-{
-    ASSERT(m_inode);
-    m_size = ceil_div(m_inode->size(), PAGE_SIZE) * PAGE_SIZE;
-    m_physical_pages.resize(page_count());
-    MM.register_vmo(*this);
+    if (should_fill_physical_pages == ShouldFillPhysicalPages::Yes)
+        m_physical_pages.resize(page_count());
 }
 
 VMObject::~VMObject()
 {
-    if (m_inode)
-        ASSERT(m_inode->vmo() == this);
     MM.unregister_vmo(*this);
 }
-
-template<typename Callback>
-void VMObject::for_each_region(Callback callback)
-{
-    // FIXME: Figure out a better data structure so we don't have to walk every single region every time an inode changes.
-    //        Perhaps VMObject could have a Vector<Region*> with all of his mappers?
-    for (auto* region : MM.m_user_regions) {
-        if (&region->vmo() == this)
-            callback(*region);
-    }
-    for (auto* region : MM.m_kernel_regions) {
-        if (&region->vmo() == this)
-            callback(*region);
-    }
-}
-
-void VMObject::inode_size_changed(Badge<Inode>, size_t old_size, size_t new_size)
-{
-    dbgprintf("VMObject::inode_size_changed: {%u:%u} %u -> %u\n",
-        m_inode->fsid(), m_inode->index(),
-        old_size, new_size);
-
-    InterruptDisabler disabler;
-
-    auto old_page_count = page_count();
-    m_size = new_size;
-
-    if (page_count() > old_page_count) {
-        // Add null pages and let the fault handler page these in when that day comes.
-        for (auto i = old_page_count; i < page_count(); ++i)
-            m_physical_pages.append(nullptr);
-    } else {
-        // Prune the no-longer valid pages. I'm not sure this is actually correct behavior.
-        for (auto i = page_count(); i < old_page_count; ++i)
-            m_physical_pages.take_last();
-    }
-
-    // FIXME: Consolidate with inode_contents_changed() so we only do a single walk.
-    for_each_region([](Region& region) {
-        ASSERT(region.page_directory());
-        MM.remap_region(*region.page_directory(), region);
-    });
-}
-
-void VMObject::inode_contents_changed(Badge<Inode>, off_t offset, ssize_t size, const u8* data)
-{
-    (void)size;
-    (void)data;
-    InterruptDisabler disabler;
-    ASSERT(offset >= 0);
-
-    // FIXME: Only invalidate the parts that actually changed.
-    for (auto& physical_page : m_physical_pages)
-        physical_page = nullptr;
-
-#if 0
-    size_t current_offset = offset;
-    size_t remaining_bytes = size;
-    const u8* data_ptr = data;
-
-    auto to_page_index = [] (size_t offset) -> size_t {
-        return offset / PAGE_SIZE;
-    };
-
-    if (current_offset & PAGE_MASK) {
-        size_t page_index = to_page_index(current_offset);
-        size_t bytes_to_copy = min(size, PAGE_SIZE - (current_offset & PAGE_MASK));
-        if (m_physical_pages[page_index]) {
-            auto* ptr = MM.quickmap_page(*m_physical_pages[page_index]);
-            memcpy(ptr, data_ptr, bytes_to_copy);
-            MM.unquickmap_page();
-        }
-        current_offset += bytes_to_copy;
-        data += bytes_to_copy;
-        remaining_bytes -= bytes_to_copy;
-    }
-
-    for (size_t page_index = to_page_index(current_offset); page_index < m_physical_pages.size(); ++page_index) {
-        size_t bytes_to_copy = PAGE_SIZE - (current_offset & PAGE_MASK);
-        if (m_physical_pages[page_index]) {
-            auto* ptr = MM.quickmap_page(*m_physical_pages[page_index]);
-            memcpy(ptr, data_ptr, bytes_to_copy);
-            MM.unquickmap_page();
-        }
-        current_offset += bytes_to_copy;
-        data += bytes_to_copy;
-    }
-#endif
-
-    // FIXME: Consolidate with inode_size_changed() so we only do a single walk.
-    for_each_region([](Region& region) {
-        ASSERT(region.page_directory());
-        MM.remap_region(*region.page_directory(), region);
-    });
-}