refactor: promote new architecture to repository root

Archive the deprecated implementation under lume-legacy, make the new kernel the default root-level build, and update repository entry points without changing kernel behavior.

1 files changed, 154 insertions, 0 deletions

diff --git a/fs/ramfs/super.cc b/fs/ramfs/super.cc
new file mode 100644
index 0000000..6f929f2
--- /dev/null
+++ b/fs/ramfs/super.cc
@@ -0,0 +1,154 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (C) 2026 Richard Qin */
+
+/*
+ * ramfs/super.cc — RamFS superblock: mount, fill_super, and init
+ */
+
+#include <lume/fs.h>
+#include <lume/dcache.h>
+#include <lume/file.h>
+#include <lume/mount.h>
+#include <lume/slab.h>
+#include <lume/kprintf.h>
+#include <lume/errno.h>
+#include <lume/fs_types.h>
+
+extern inode* ramfs_get_inode(super_block* sb, const inode* dir,
+                              uint32 mode, uint32 rdev);
+
+/* Superblock allocation helper (defined in super.cc) */
+extern super_block* alloc_super(file_system_type* type);
+
+/* ================================================================== */
+/*  ramfs super_operations                                            */
+/* ================================================================== */
+
+static inode* ramfs_alloc_inode(super_block* sb)
+{
+    return new inode{};
+}
+
+static void ramfs_destroy_inode(inode* ip)
+{
+    /* Free ramfs_file_data if any */
+    if (ip->i_private) {
+        struct ramfs_file_data {
+            char* buf;
+            uint64 capacity;
+        };
+        auto* data = static_cast<ramfs_file_data*>(ip->i_private);
+        delete[] data->buf;
+        delete data;
+    }
+    delete ip;
+}
+
+static int ramfs_statfs(dentry* de, kstatfs* buf)
+{
+    /* Simple fake values */
+    buf->f_type = 0x858458f6;  /* RAMFS_MAGIC */
+    buf->f_bsize = 4096;
+    buf->f_blocks = 0;
+    buf->f_bfree = 0;
+    buf->f_bavail = 0;
+    buf->f_files = 0;
+    buf->f_ffree = 0;
+    buf->f_namelen = 255;
+    buf->f_frsize = 4096;
+    buf->f_flags = 0;
+    return 0;
+}
+
+static super_operations ramfs_sops;
+
+static void ramfs_sops_init()
+{
+    ramfs_sops.alloc_inode   = ramfs_alloc_inode;
+    ramfs_sops.destroy_inode = ramfs_destroy_inode;
+    ramfs_sops.free_inode    = nullptr;
+    ramfs_sops.dirty_inode   = nullptr;
+    ramfs_sops.write_inode   = nullptr;
+    ramfs_sops.drop_inode    = nullptr;
+    ramfs_sops.evict_inode   = nullptr;
+    ramfs_sops.put_super     = nullptr;
+    ramfs_sops.sync_fs       = nullptr;
+    ramfs_sops.statfs        = ramfs_statfs;
+    ramfs_sops.umount_begin  = nullptr;
+}
+
+/* ================================================================== */
+/*  ramfs_fill_super                                                  */
+/* ================================================================== */
+
+static int ramfs_fill_super(super_block* sb, void* data, int silent)
+{
+    sb->s_op = &ramfs_sops;
+    sb->s_magic = 0x858458f6;
+    sb->s_blocksize = 4096;
+    sb->s_blocksize_bits = 12;
+    sb->s_maxbytes = 0x7FFFFFFFFFFFFFFFLL;
+    sb->s_time_gran = 1;
+
+    /* Create root inode */
+    inode* root_ip = ramfs_get_inode(sb, nullptr, S_IFDIR | 0755, 0);
+    if (!root_ip) return -ENOMEM;
+
+    /* Create root dentry */
+    sb->s_root = d_make_root(root_ip);
+    if (!sb->s_root)
+        return -ENOMEM;
+
+    return 0;
+}
+
+/* ================================================================== */
+/*  ramfs_mount                                                       */
+/* ================================================================== */
+
+static super_block* ramfs_mount(file_system_type* type, int flags,
+                                const char* dev_name, void* data)
+{
+    super_block* sb = alloc_super(type);
+    if (!sb) return nullptr;
+
+    int err = ramfs_fill_super(sb, data, flags & SB_SILENT);
+    if (err) {
+        delete sb;
+        return nullptr;
+    }
+
+    return sb;
+}
+
+static void ramfs_kill_sb(super_block* sb)
+{
+    /* Phase 1: no cleanup needed for ramfs */
+    (void)sb;
+}
+
+/* ================================================================== */
+/*  Filesystem type registration                                      */
+/* ================================================================== */
+
+static file_system_type ramfs_fs_type;
+
+extern void ramfs_file_ops_init();
+extern void ramfs_dir_inode_ops_init();
+
+void ramfs_init()
+{
+    /* Runtime init to avoid un-relocated absolute pointers in .data */
+    ramfs_sops_init();
+    ramfs_file_ops_init();
+    ramfs_dir_inode_ops_init();
+
+    ramfs_fs_type.name     = "ramfs";
+    ramfs_fs_type.fs_flags = FS_NO_DEVICE;
+    ramfs_fs_type.mount    = ramfs_mount;
+    ramfs_fs_type.kill_sb  = ramfs_kill_sb;
+    list_init(&ramfs_fs_type.fs_list);
+
+    register_filesystem(&ramfs_fs_type);
+}
+