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 | spinlock_t kernfs_idr_lock; /* root->ino_idr */ |
42 | u32 last_id_lowbits; |
43 | u32 id_highbits; |
44 | struct kernfs_syscall_ops *syscall_ops; |
45 | |
46 | /* list of kernfs_super_info of this root, protected by kernfs_rwsem */ |
47 | struct list_head supers; |
48 | |
49 | wait_queue_head_t deactivate_waitq; |
50 | struct rw_semaphore kernfs_rwsem; |
51 | struct rw_semaphore kernfs_iattr_rwsem; |
52 | struct rw_semaphore kernfs_supers_rwsem; |
53 | |
54 | /* kn->parent and kn->name */ |
55 | rwlock_t kernfs_rename_lock; |
56 | |
57 | struct rcu_head rcu; |
58 | }; |
59 | |
60 | /* +1 to avoid triggering overflow warning when negating it */ |
61 | #define KN_DEACTIVATED_BIAS (INT_MIN + 1) |
62 | |
63 | /* KERNFS_TYPE_MASK and types are defined in include/linux/kernfs.h */ |
64 | |
65 | /** |
66 | * kernfs_root - find out the kernfs_root a kernfs_node belongs to |
67 | * @kn: kernfs_node of interest |
68 | * |
69 | * Return: the kernfs_root @kn belongs to. |
70 | */ |
71 | static inline struct kernfs_root *kernfs_root(const struct kernfs_node *kn) |
72 | { |
73 | const struct kernfs_node *knp; |
74 | /* if parent exists, it's always a dir; otherwise, @sd is a dir */ |
75 | guard(rcu)(); |
76 | knp = rcu_dereference(kn->__parent); |
77 | if (knp) |
78 | kn = knp; |
79 | return kn->dir.root; |
80 | } |
81 | |
82 | /* |
83 | * mount.c |
84 | */ |
85 | struct kernfs_super_info { |
86 | struct super_block *sb; |
87 | |
88 | /* |
89 | * The root associated with this super_block. Each super_block is |
90 | * identified by the root and ns it's associated with. |
91 | */ |
92 | struct kernfs_root *root; |
93 | |
94 | /* |
95 | * Each sb is associated with one namespace tag, currently the |
96 | * network namespace of the task which mounted this kernfs |
97 | * instance. If multiple tags become necessary, make the following |
98 | * an array and compare kernfs_node tag against every entry. |
99 | */ |
100 | const void *ns; |
101 | |
102 | /* anchored at kernfs_root->supers, protected by kernfs_rwsem */ |
103 | struct list_head node; |
104 | }; |
105 | #define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info)) |
106 | |
107 | static inline bool kernfs_root_is_locked(const struct kernfs_node *kn) |
108 | { |
109 | return lockdep_is_held(&kernfs_root(kn)->kernfs_rwsem); |
110 | } |
111 | |
112 | static inline bool kernfs_rename_is_locked(const struct kernfs_node *kn) |
113 | { |
114 | return lockdep_is_held(&kernfs_root(kn)->kernfs_rename_lock); |
115 | } |
116 | |
117 | static inline const char *kernfs_rcu_name(const struct kernfs_node *kn) |
118 | { |
119 | return rcu_dereference_check(kn->name, kernfs_root_is_locked(kn)); |
120 | } |
121 | |
122 | static inline struct kernfs_node *kernfs_parent(const struct kernfs_node *kn) |
123 | { |
124 | /* |
125 | * The kernfs_node::__parent remains valid within a RCU section. The kn |
126 | * can be reparented (and renamed) which changes the entry. This can be |
127 | * avoided by locking kernfs_root::kernfs_rwsem or |
128 | * kernfs_root::kernfs_rename_lock. |
129 | * Both locks can be used to obtain a reference on __parent. Once the |
130 | * reference count reaches 0 then the node is about to be freed |
131 | * and can not be renamed (or become a different parent) anymore. |
132 | */ |
133 | return rcu_dereference_check(kn->__parent, |
134 | kernfs_root_is_locked(kn) || |
135 | kernfs_rename_is_locked(kn) || |
136 | !atomic_read(&kn->count)); |
137 | } |
138 | |
139 | static inline struct kernfs_node *kernfs_dentry_node(struct dentry *dentry) |
140 | { |
141 | if (d_really_is_negative(dentry)) |
142 | return NULL; |
143 | return d_inode(dentry)->i_private; |
144 | } |
145 | |
146 | static inline void kernfs_set_rev(struct kernfs_node *parent, |
147 | struct dentry *dentry) |
148 | { |
149 | dentry->d_time = parent->dir.rev; |
150 | } |
151 | |
152 | static inline void kernfs_inc_rev(struct kernfs_node *parent) |
153 | { |
154 | parent->dir.rev++; |
155 | } |
156 | |
157 | static inline bool kernfs_dir_changed(struct kernfs_node *parent, |
158 | struct dentry *dentry) |
159 | { |
160 | if (parent->dir.rev != dentry->d_time) |
161 | return true; |
162 | return false; |
163 | } |
164 | |
165 | extern const struct super_operations kernfs_sops; |
166 | extern struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache; |
167 | |
168 | /* |
169 | * inode.c |
170 | */ |
171 | extern const struct xattr_handler * const kernfs_xattr_handlers[]; |
172 | void kernfs_evict_inode(struct inode *inode); |
173 | int kernfs_iop_permission(struct mnt_idmap *idmap, |
174 | struct inode *inode, int mask); |
175 | int kernfs_iop_setattr(struct mnt_idmap *idmap, struct dentry *dentry, |
176 | struct iattr *iattr); |
177 | int kernfs_iop_getattr(struct mnt_idmap *idmap, |
178 | const struct path *path, struct kstat *stat, |
179 | u32 request_mask, unsigned int query_flags); |
180 | ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size); |
181 | int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr); |
182 | |
183 | /* |
184 | * dir.c |
185 | */ |
186 | extern const struct dentry_operations kernfs_dops; |
187 | extern const struct file_operations kernfs_dir_fops; |
188 | extern const struct inode_operations kernfs_dir_iops; |
189 | |
190 | struct kernfs_node *kernfs_get_active(struct kernfs_node *kn); |
191 | void kernfs_put_active(struct kernfs_node *kn); |
192 | int kernfs_add_one(struct kernfs_node *kn); |
193 | struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, |
194 | const char *name, umode_t mode, |
195 | kuid_t uid, kgid_t gid, |
196 | unsigned flags); |
197 | |
198 | /* |
199 | * file.c |
200 | */ |
201 | extern const struct file_operations kernfs_file_fops; |
202 | |
203 | bool kernfs_should_drain_open_files(struct kernfs_node *kn); |
204 | void kernfs_drain_open_files(struct kernfs_node *kn); |
205 | |
206 | /* |
207 | * symlink.c |
208 | */ |
209 | extern const struct inode_operations kernfs_symlink_iops; |
210 | |
211 | /* |
212 | * kernfs locks |
213 | */ |
214 | extern struct kernfs_global_locks *kernfs_locks; |
215 | #endif /* __KERNFS_INTERNAL_H */ |
216 | |