1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * fs/kernfs/kernfs-internal.h - kernfs internal header file
4 *
5 * Copyright (c) 2001-3 Patrick Mochel
6 * Copyright (c) 2007 SUSE Linux Products GmbH
7 * Copyright (c) 2007, 2013 Tejun Heo <teheo@suse.de>
8 */
9
10#ifndef __KERNFS_INTERNAL_H
11#define __KERNFS_INTERNAL_H
12
13#include <linux/lockdep.h>
14#include <linux/fs.h>
15#include <linux/mutex.h>
16#include <linux/rwsem.h>
17#include <linux/xattr.h>
18
19#include <linux/kernfs.h>
20#include <linux/fs_context.h>
21
22struct kernfs_iattrs {
23	kuid_t			ia_uid;
24	kgid_t			ia_gid;
25	struct timespec64	ia_atime;
26	struct timespec64	ia_mtime;
27	struct timespec64	ia_ctime;
28
29	struct simple_xattrs	xattrs;
30	atomic_t		nr_user_xattrs;
31	atomic_t		user_xattr_size;
32};
33
34struct kernfs_root {
35	/* published fields */
36	struct kernfs_node	*kn;
37	unsigned int		flags;	/* KERNFS_ROOT_* flags */
38
39	/* private fields, do not use outside kernfs proper */
40	struct idr		ino_idr;
41	u32			last_id_lowbits;
42	u32			id_highbits;
43	struct kernfs_syscall_ops *syscall_ops;
44
45	/* list of kernfs_super_info of this root, protected by kernfs_rwsem */
46	struct list_head	supers;
47
48	wait_queue_head_t	deactivate_waitq;
49	struct rw_semaphore	kernfs_rwsem;
50	struct rw_semaphore	kernfs_iattr_rwsem;
51	struct rw_semaphore	kernfs_supers_rwsem;
52};
53
54/* +1 to avoid triggering overflow warning when negating it */
55#define KN_DEACTIVATED_BIAS		(INT_MIN + 1)
56
57/* KERNFS_TYPE_MASK and types are defined in include/linux/kernfs.h */
58
59/**
60 * kernfs_root - find out the kernfs_root a kernfs_node belongs to
61 * @kn: kernfs_node of interest
62 *
63 * Return: the kernfs_root @kn belongs to.
64 */
65static inline struct kernfs_root *kernfs_root(struct kernfs_node *kn)
66{
67	/* if parent exists, it's always a dir; otherwise, @sd is a dir */
68	if (kn->parent)
69		kn = kn->parent;
70	return kn->dir.root;
71}
72
73/*
74 * mount.c
75 */
76struct kernfs_super_info {
77	struct super_block	*sb;
78
79	/*
80	 * The root associated with this super_block.  Each super_block is
81	 * identified by the root and ns it's associated with.
82	 */
83	struct kernfs_root	*root;
84
85	/*
86	 * Each sb is associated with one namespace tag, currently the
87	 * network namespace of the task which mounted this kernfs
88	 * instance.  If multiple tags become necessary, make the following
89	 * an array and compare kernfs_node tag against every entry.
90	 */
91	const void		*ns;
92
93	/* anchored at kernfs_root->supers, protected by kernfs_rwsem */
94	struct list_head	node;
95};
96#define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info))
97
98static inline struct kernfs_node *kernfs_dentry_node(struct dentry *dentry)
99{
100	if (d_really_is_negative(dentry))
101		return NULL;
102	return d_inode(dentry)->i_private;
103}
104
105static inline void kernfs_set_rev(struct kernfs_node *parent,
106				  struct dentry *dentry)
107{
108	dentry->d_time = parent->dir.rev;
109}
110
111static inline void kernfs_inc_rev(struct kernfs_node *parent)
112{
113	parent->dir.rev++;
114}
115
116static inline bool kernfs_dir_changed(struct kernfs_node *parent,
117				      struct dentry *dentry)
118{
119	if (parent->dir.rev != dentry->d_time)
120		return true;
121	return false;
122}
123
124extern const struct super_operations kernfs_sops;
125extern struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache;
126
127/*
128 * inode.c
129 */
130extern const struct xattr_handler *kernfs_xattr_handlers[];
131void kernfs_evict_inode(struct inode *inode);
132int kernfs_iop_permission(struct mnt_idmap *idmap,
133			  struct inode *inode, int mask);
134int kernfs_iop_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
135		       struct iattr *iattr);
136int kernfs_iop_getattr(struct mnt_idmap *idmap,
137		       const struct path *path, struct kstat *stat,
138		       u32 request_mask, unsigned int query_flags);
139ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size);
140int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr);
141
142/*
143 * dir.c
144 */
145extern const struct dentry_operations kernfs_dops;
146extern const struct file_operations kernfs_dir_fops;
147extern const struct inode_operations kernfs_dir_iops;
148
149struct kernfs_node *kernfs_get_active(struct kernfs_node *kn);
150void kernfs_put_active(struct kernfs_node *kn);
151int kernfs_add_one(struct kernfs_node *kn);
152struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
153				    const char *name, umode_t mode,
154				    kuid_t uid, kgid_t gid,
155				    unsigned flags);
156
157/*
158 * file.c
159 */
160extern const struct file_operations kernfs_file_fops;
161
162bool kernfs_should_drain_open_files(struct kernfs_node *kn);
163void kernfs_drain_open_files(struct kernfs_node *kn);
164
165/*
166 * symlink.c
167 */
168extern const struct inode_operations kernfs_symlink_iops;
169
170/*
171 * kernfs locks
172 */
173extern struct kernfs_global_locks *kernfs_locks;
174#endif	/* __KERNFS_INTERNAL_H */
175