diff options
Diffstat (limited to 'fs/ramfs/inode.cc')
| -rw-r--r-- | fs/ramfs/inode.cc | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/fs/ramfs/inode.cc b/fs/ramfs/inode.cc new file mode 100644 index 0000000..c5e49bf --- /dev/null +++ b/fs/ramfs/inode.cc @@ -0,0 +1,164 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* Copyright (C) 2026 Richard Qin */ + +/* + * ramfs/inode.cc — RamFS inode operations + * + * A simple in-memory filesystem (like Linux tmpfs without swap). + * All data lives in memory via the page cache. + */ + +#include <lume/fs.h> +#include <lume/dcache.h> +#include <lume/file.h> +#include <lume/slab.h> +#include <lume/errno.h> +#include <lume/fs_types.h> + +/* Forward declarations */ +extern file_operations ramfs_file_operations; +extern file_operations ramfs_dir_operations; +extern inode_operations ramfs_dir_inode_operations; + +/* ================================================================== */ +/* ramfs_get_inode — allocate + init an inode for ramfs */ +/* ================================================================== */ + +inode* ramfs_get_inode(super_block* sb, const inode* dir, uint32 mode, uint32 rdev) +{ + inode* ip = new_inode(sb); + if (!ip) return nullptr; + + inode_init_owner(ip, dir, mode); + /* TODO: set timestamps to current time when we have a time source */ + + switch (mode & S_IFMT) { + case S_IFREG: + ip->i_op = nullptr; /* regular files don't need inode_ops for Phase 1 */ + ip->i_fop = &ramfs_file_operations; + break; + case S_IFDIR: + ip->i_op = &ramfs_dir_inode_operations; + ip->i_fop = &ramfs_dir_operations; + inc_nlink(ip); /* directories start with nlink=2 (. and parent's link) */ + break; + case S_IFLNK: + /* Symlink: stub for Phase 1 */ + break; + default: + /* Character/block devices: i_rdev */ + ip->i_rdev = rdev; + break; + } + + return ip; +} + +/* ================================================================== */ +/* Directory inode operations */ +/* ================================================================== */ + +static dentry* ramfs_lookup(inode* dir, dentry* de, unsigned int flags) +{ + (void)dir; + (void)flags; + /* For ramfs, everything is in dcache. If we get here, it means + * d_lookup() already failed, so this is a negative dentry. + * Just return nullptr to let the caller see de->d_inode == NULL. */ + return nullptr; +} + +static int ramfs_create(inode* dir, dentry* de, uint32 mode, bool excl) +{ + (void)excl; + inode* ip = ramfs_get_inode(dir->i_sb, dir, mode | S_IFREG, 0); + if (!ip) return -ENOMEM; + + d_instantiate(de, ip); + dget(de); + dir->i_size += de->d_name.len; + mark_inode_dirty(dir); + return 0; +} + +static int ramfs_mkdir(inode* dir, dentry* de, uint32 mode) +{ + inode* ip = ramfs_get_inode(dir->i_sb, dir, mode | S_IFDIR, 0); + if (!ip) return -ENOMEM; + + d_instantiate(de, ip); + dget(de); + inc_nlink(dir); + dir->i_size += de->d_name.len; + mark_inode_dirty(dir); + return 0; +} + +static int ramfs_rmdir(inode* dir, dentry* de) +{ + /* Check if directory is empty */ + if (!list_empty(&de->d_children)) + return -ENOTEMPTY; + + drop_nlink(de->d_inode); /* remove . link */ + drop_nlink(de->d_inode); /* remove parent's link */ + drop_nlink(dir); + d_delete(de); + dir->i_size -= de->d_name.len; + mark_inode_dirty(dir); + return 0; +} + +static int ramfs_unlink(inode* dir, dentry* de) +{ + drop_nlink(de->d_inode); + d_delete(de); + dir->i_size -= de->d_name.len; + mark_inode_dirty(dir); + return 0; +} + +static int ramfs_link(dentry* old_de, inode* dir, dentry* new_de) +{ + inode* ip = old_de->d_inode; + if (!ip) return -ENOENT; + + inc_nlink(ip); + ihold(ip); + d_instantiate(new_de, ip); + dget(new_de); + dir->i_size += new_de->d_name.len; + mark_inode_dirty(dir); + return 0; +} + +static int ramfs_mknod(inode* dir, dentry* de, uint32 mode, uint32 rdev) +{ + inode* ip = ramfs_get_inode(dir->i_sb, dir, mode, rdev); + if (!ip) return -ENOMEM; + + d_instantiate(de, ip); + dget(de); + dir->i_size += de->d_name.len; + mark_inode_dirty(dir); + return 0; +} + +inode_operations ramfs_dir_inode_operations; + +void ramfs_dir_inode_ops_init() +{ + ramfs_dir_inode_operations.lookup = ramfs_lookup; + ramfs_dir_inode_operations.create = ramfs_create; + ramfs_dir_inode_operations.link = ramfs_link; + ramfs_dir_inode_operations.unlink = ramfs_unlink; + ramfs_dir_inode_operations.symlink = nullptr; + ramfs_dir_inode_operations.mkdir = ramfs_mkdir; + ramfs_dir_inode_operations.rmdir = ramfs_rmdir; + ramfs_dir_inode_operations.mknod = ramfs_mknod; + ramfs_dir_inode_operations.rename = nullptr; + ramfs_dir_inode_operations.setattr = nullptr; + ramfs_dir_inode_operations.getattr = nullptr; + ramfs_dir_inode_operations.get_link = nullptr; + ramfs_dir_inode_operations.permission = nullptr; +} |