xref: /linux/fs/kernfs/kernfs-internal.h (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
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 	struct rw_semaphore	kernfs_iattr_rwsem;
51 	struct rw_semaphore	kernfs_supers_rwsem;
52 
53 	struct rcu_head		rcu;
54 };
55 
56 /* +1 to avoid triggering overflow warning when negating it */
57 #define KN_DEACTIVATED_BIAS		(INT_MIN + 1)
58 
59 /* KERNFS_TYPE_MASK and types are defined in include/linux/kernfs.h */
60 
61 /**
62  * kernfs_root - find out the kernfs_root a kernfs_node belongs to
63  * @kn: kernfs_node of interest
64  *
65  * Return: the kernfs_root @kn belongs to.
66  */
kernfs_root(struct kernfs_node * kn)67 static inline struct kernfs_root *kernfs_root(struct kernfs_node *kn)
68 {
69 	/* if parent exists, it's always a dir; otherwise, @sd is a dir */
70 	if (kn->parent)
71 		kn = kn->parent;
72 	return kn->dir.root;
73 }
74 
75 /*
76  * mount.c
77  */
78 struct kernfs_super_info {
79 	struct super_block	*sb;
80 
81 	/*
82 	 * The root associated with this super_block.  Each super_block is
83 	 * identified by the root and ns it's associated with.
84 	 */
85 	struct kernfs_root	*root;
86 
87 	/*
88 	 * Each sb is associated with one namespace tag, currently the
89 	 * network namespace of the task which mounted this kernfs
90 	 * instance.  If multiple tags become necessary, make the following
91 	 * an array and compare kernfs_node tag against every entry.
92 	 */
93 	const void		*ns;
94 
95 	/* anchored at kernfs_root->supers, protected by kernfs_rwsem */
96 	struct list_head	node;
97 };
98 #define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info))
99 
kernfs_dentry_node(struct dentry * dentry)100 static inline struct kernfs_node *kernfs_dentry_node(struct dentry *dentry)
101 {
102 	if (d_really_is_negative(dentry))
103 		return NULL;
104 	return d_inode(dentry)->i_private;
105 }
106 
kernfs_set_rev(struct kernfs_node * parent,struct dentry * dentry)107 static inline void kernfs_set_rev(struct kernfs_node *parent,
108 				  struct dentry *dentry)
109 {
110 	dentry->d_time = parent->dir.rev;
111 }
112 
kernfs_inc_rev(struct kernfs_node * parent)113 static inline void kernfs_inc_rev(struct kernfs_node *parent)
114 {
115 	parent->dir.rev++;
116 }
117 
kernfs_dir_changed(struct kernfs_node * parent,struct dentry * dentry)118 static inline bool kernfs_dir_changed(struct kernfs_node *parent,
119 				      struct dentry *dentry)
120 {
121 	if (parent->dir.rev != dentry->d_time)
122 		return true;
123 	return false;
124 }
125 
126 extern const struct super_operations kernfs_sops;
127 extern struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache;
128 
129 /*
130  * inode.c
131  */
132 extern const struct xattr_handler * const kernfs_xattr_handlers[];
133 void kernfs_evict_inode(struct inode *inode);
134 int kernfs_iop_permission(struct mnt_idmap *idmap,
135 			  struct inode *inode, int mask);
136 int kernfs_iop_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
137 		       struct iattr *iattr);
138 int kernfs_iop_getattr(struct mnt_idmap *idmap,
139 		       const struct path *path, struct kstat *stat,
140 		       u32 request_mask, unsigned int query_flags);
141 ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size);
142 int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr);
143 
144 /*
145  * dir.c
146  */
147 extern const struct dentry_operations kernfs_dops;
148 extern const struct file_operations kernfs_dir_fops;
149 extern const struct inode_operations kernfs_dir_iops;
150 
151 struct kernfs_node *kernfs_get_active(struct kernfs_node *kn);
152 void kernfs_put_active(struct kernfs_node *kn);
153 int kernfs_add_one(struct kernfs_node *kn);
154 struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
155 				    const char *name, umode_t mode,
156 				    kuid_t uid, kgid_t gid,
157 				    unsigned flags);
158 
159 /*
160  * file.c
161  */
162 extern const struct file_operations kernfs_file_fops;
163 
164 bool kernfs_should_drain_open_files(struct kernfs_node *kn);
165 void kernfs_drain_open_files(struct kernfs_node *kn);
166 
167 /*
168  * symlink.c
169  */
170 extern const struct inode_operations kernfs_symlink_iops;
171 
172 /*
173  * kernfs locks
174  */
175 extern struct kernfs_global_locks *kernfs_locks;
176 #endif	/* __KERNFS_INTERNAL_H */
177