Kernel/FileSystem: Make Inode::{write,read}_bytes methods non-virtual

We make these methods non-virtual because we want to ensure we properly
enforce locking of the m_inode_lock mutex. Also, for write operations,
we want to call prepare_to_write_data before the actual write. The
previous design required us to ensure the callers do that at various
places which lead to hard-to-find bugs. By moving everything to a place
where we call prepare_to_write_data only once, we eliminate a possibilty
of forgeting to call it on some code path in the kernel.

Kernel/FileSystem/SysFS.cpp

@@ -58,7 +58,7 @@ ErrorOr<void> SysFSInode::attach(OpenFileDescription& description)
     return m_associated_component->refresh_data(description);
 }
 
-ErrorOr<size_t> SysFSInode::read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription* fd) const
+ErrorOr<size_t> SysFSInode::read_bytes_locked(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription* fd) const
 {
     return m_associated_component->read_bytes(offset, count, buffer, fd);
 }
@@ -91,7 +91,7 @@ ErrorOr<void> SysFSInode::flush_metadata()
     return {};
 }
 
-ErrorOr<size_t> SysFSInode::write_bytes(off_t offset, size_t count, UserOrKernelBuffer const& buffer, OpenFileDescription* fd)
+ErrorOr<size_t> SysFSInode::write_bytes_locked(off_t offset, size_t count, UserOrKernelBuffer const& buffer, OpenFileDescription* fd)
 {
     return m_associated_component->write_bytes(offset, count, buffer, fd);
 }