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 
22 struct 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 
34 struct 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 };
51 
52 /* +1 to avoid triggering overflow warning when negating it */
53 #define KN_DEACTIVATED_BIAS		(INT_MIN + 1)
54 
55 /* KERNFS_TYPE_MASK and types are defined in include/linux/kernfs.h */
56 
57 /**
58  * kernfs_root - find out the kernfs_root a kernfs_node belongs to
59  * @kn: kernfs_node of interest
60  *
61  * Return the kernfs_root @kn belongs to.
62  */
kernfs_root(struct kernfs_node * kn)63 static inline struct kernfs_root *kernfs_root(struct kernfs_node *kn)
64 {
65 	/* if parent exists, it's always a dir; otherwise, @sd is a dir */
66 	if (kn->parent)
67 		kn = kn->parent;
68 	return kn->dir.root;
69 }
70 
71 /*
72  * mount.c
73  */
74 struct kernfs_super_info {
75 	struct super_block	*sb;
76 
77 	/*
78 	 * The root associated with this super_block.  Each super_block is
79 	 * identified by the root and ns it's associated with.
80 	 */
81 	struct kernfs_root	*root;
82 
83 	/*
84 	 * Each sb is associated with one namespace tag, currently the
85 	 * network namespace of the task which mounted this kernfs
86 	 * instance.  If multiple tags become necessary, make the following
87 	 * an array and compare kernfs_node tag against every entry.
88 	 */
89 	const void		*ns;
90 
91 	/* anchored at kernfs_root->supers, protected by kernfs_rwsem */
92 	struct list_head	node;
93 };
94 #define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info))
95 
kernfs_dentry_node(struct dentry * dentry)96 static inline struct kernfs_node *kernfs_dentry_node(struct dentry *dentry)
97 {
98 	if (d_really_is_negative(dentry))
99 		return NULL;
100 	return d_inode(dentry)->i_private;
101 }
102 
kernfs_set_rev(struct kernfs_node * parent,struct dentry * dentry)103 static inline void kernfs_set_rev(struct kernfs_node *parent,
104 				  struct dentry *dentry)
105 {
106 	dentry->d_time = parent->dir.rev;
107 }
108 
kernfs_inc_rev(struct kernfs_node * parent)109 static inline void kernfs_inc_rev(struct kernfs_node *parent)
110 {
111 	parent->dir.rev++;
112 }
113 
kernfs_dir_changed(struct kernfs_node * parent,struct dentry * dentry)114 static inline bool kernfs_dir_changed(struct kernfs_node *parent,
115 				      struct dentry *dentry)
116 {
117 	if (parent->dir.rev != dentry->d_time)
118 		return true;
119 	return false;
120 }
121 
122 extern const struct super_operations kernfs_sops;
123 extern struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache;
124 
125 /*
126  * inode.c
127  */
128 extern const struct xattr_handler *kernfs_xattr_handlers[];
129 void kernfs_evict_inode(struct inode *inode);
130 int kernfs_iop_permission(struct user_namespace *mnt_userns,
131 			  struct inode *inode, int mask);
132 int kernfs_iop_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
133 		       struct iattr *iattr);
134 int kernfs_iop_getattr(struct user_namespace *mnt_userns,
135 		       const struct path *path, struct kstat *stat,
136 		       u32 request_mask, unsigned int query_flags);
137 ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size);
138 int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr);
139 
140 /*
141  * dir.c
142  */
143 extern const struct dentry_operations kernfs_dops;
144 extern const struct file_operations kernfs_dir_fops;
145 extern const struct inode_operations kernfs_dir_iops;
146 
147 struct kernfs_node *kernfs_get_active(struct kernfs_node *kn);
148 void kernfs_put_active(struct kernfs_node *kn);
149 int kernfs_add_one(struct kernfs_node *kn);
150 struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
151 				    const char *name, umode_t mode,
152 				    kuid_t uid, kgid_t gid,
153 				    unsigned flags);
154 
155 /*
156  * file.c
157  */
158 extern const struct file_operations kernfs_file_fops;
159 
160 bool kernfs_should_drain_open_files(struct kernfs_node *kn);
161 void kernfs_drain_open_files(struct kernfs_node *kn);
162 
163 /*
164  * symlink.c
165  */
166 extern const struct inode_operations kernfs_symlink_iops;
167 
168 /*
169  * kernfs locks
170  */
171 extern struct kernfs_global_locks *kernfs_locks;
172 #endif	/* __KERNFS_INTERNAL_H */
173