1 files changed, 166 insertions, 0 deletions
diff --git a/fs/inode.cc b/fs/inode.cc
new file mode 100644
index 0000000..1d3d006
--- /dev/null
+++ b/fs/inode.cc
@@ -0,0 +1,166 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (C) 2026 Richard Qin */
+
+/*
+ * inode.cc — Inode allocation, lifecycle, and generic helpers
+ */
+
+#include <lume/fs.h>
+#include <lume/dcache.h>
+#include <lume/slab.h>
+#include <lume/errno.h>
+
+namespace {
+lume::atomic<uint64> g_next_ino{1};
+} // namespace
+
+/* ================================================================== */
+/*  new_inode — allocate a fresh inode on a superblock                */
+/* ================================================================== */
+
+inode* new_inode(super_block* sb)
+{
+    inode* ip = nullptr;
+
+    if (sb->s_op && sb->s_op->alloc_inode)
+        ip = sb->s_op->alloc_inode(sb);
+    else
+        ip = new inode{};
+
+    if (!ip) return nullptr;
+
+    /* Zero-init key fields */
+    ip->i_sb = sb;
+    ip->i_ino = g_next_ino.fetch_add(1);
+    ip->i_mode = 0;
+    ip->i_flags = 0;
+    ip->i_uid = 0;
+    ip->i_gid = 0;
+    ip->i_nlink = 1;
+    ip->i_rdev = 0;
+    ip->i_size = 0;
+    ip->i_blocks = 0;
+    ip->i_bytes = 0;
+    ip->i_blkbits = sb->s_blocksize_bits;
+    ip->i_generation = 0;
+    ip->i_state = I_NEW;
+    ip->i_count.store(1);
+    ip->i_writecount.store(0);
+
+    ip->i_atime_sec = ip->i_mtime_sec = ip->i_ctime_sec = 0;
+    ip->i_atime_nsec = ip->i_mtime_nsec = ip->i_ctime_nsec = 0;
+
+    ip->i_op = nullptr;
+    ip->i_fop = nullptr;
+    ip->i_mapping = &ip->i_data;
+    ip->i_private = nullptr;
+    ip->i_pipe = nullptr;
+
+    /* Init embedded address_space */
+    ip->i_data.host = ip;
+    ip->i_data.a_ops = nullptr;
+    ip->i_data.nrpages = 0;
+    ip->i_data.flags = 0;
+
+    /* Init lists */
+    list_init(&ip->i_sb_list);
+    list_init(&ip->i_dentry);
+
+    /* Add to superblock's inode list */
+    {
+        LockGuard guard(sb->s_inode_list_lock);
+        list_add_tail(&ip->i_sb_list, &sb->s_inodes);
+    }
+
+    return ip;
+}
+
+/* ================================================================== */
+/*  ihold / iput — reference counting                                */
+/* ================================================================== */
+
+void ihold(inode* ip)
+{
+    ip->i_count.fetch_add(1);
+}
+
+void iput(inode* ip)
+{
+    if (!ip) return;
+
+    int old = ip->i_count.fetch_sub(1);
+    if (old > 1) return;
+
+    /* Last reference dropped — evict */
+    if (ip->i_sb->s_op && ip->i_sb->s_op->evict_inode)
+        ip->i_sb->s_op->evict_inode(ip);
+
+    /* Remove from sb list */
+    {
+        LockGuard guard(ip->i_sb->s_inode_list_lock);
+        list_del(&ip->i_sb_list);
+    }
+
+    if (ip->i_sb->s_op && ip->i_sb->s_op->destroy_inode)
+        ip->i_sb->s_op->destroy_inode(ip);
+    else
+        delete ip;
+}
+
+/* ================================================================== */
+/*  nlink helpers                                                     */
+/* ================================================================== */
+
+void set_nlink(inode* ip, uint32 nlink) { ip->i_nlink = nlink; }
+void inc_nlink(inode* ip)               { ip->i_nlink++; }
+void drop_nlink(inode* ip)              { ip->i_nlink--; }
+void clear_nlink(inode* ip)             { ip->i_nlink = 0; }
+
+/* ================================================================== */
+/*  inode_init_owner                                                  */
+/* ================================================================== */
+
+void inode_init_owner(inode* ip, const inode* dir, uint32 mode)
+{
+    ip->i_uid = 0;  /* Phase 1: always root */
+    ip->i_gid = 0;
+    ip->i_mode = mode;
+}
+
+/* ================================================================== */
+/*  generic_fillattr — fill kstat from inode (used by getattr)        */
+/* ================================================================== */
+
+void generic_fillattr(inode* ip, kstat* stat)
+{
+    stat->st_dev = ip->i_sb->s_dev;
+    stat->st_ino = ip->i_ino;
+    stat->st_mode = ip->i_mode;
+    stat->st_nlink = ip->i_nlink;
+    stat->st_uid = ip->i_uid;
+    stat->st_gid = ip->i_gid;
+    stat->st_rdev = ip->i_rdev;
+    stat->__pad = 0;
+    stat->st_size = ip->i_size;
+    stat->st_blksize = 1 << ip->i_blkbits;
+    stat->__pad2 = 0;
+    stat->st_blocks = ip->i_blocks;
+    stat->st_atime_sec = ip->i_atime_sec;
+    stat->st_atime_nsec = ip->i_atime_nsec;
+    stat->st_mtime_sec = ip->i_mtime_sec;
+    stat->st_mtime_nsec = ip->i_mtime_nsec;
+    stat->st_ctime_sec = ip->i_ctime_sec;
+    stat->st_ctime_nsec = ip->i_ctime_nsec;
+    stat->__unused[0] = 0;
+    stat->__unused[1] = 0;
+}
+
+/* ================================================================== */
+/*  mark_inode_dirty (stub)                                           */
+/* ================================================================== */
+
+void mark_inode_dirty(inode* ip)
+{
+    ip->i_state |= I_DIRTY_SYNC;
+    /* Phase 1: no writeback, ramfs is memory-only */
+}