1 /* -*- mode: c; c-basic-offset:8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * configfs_internal.h - Internal stuff for configfs
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public
8  * License as published by the Free Software Foundation; either
9  * version 2 of the License, or (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public
17  * License along with this program; if not, write to the
18  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19  * Boston, MA 021110-1307, USA.
20  *
21  * Based on sysfs:
22  * 	sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
23  *
24  * configfs Copyright (C) 2005 Oracle.  All rights reserved.
25  */
26 
27 #include <linux/slab.h>
28 #include <linux/list.h>
29 
30 struct configfs_dirent {
31 	atomic_t		s_count;
32 	int			s_dependent_count;
33 	struct list_head	s_sibling;
34 	struct list_head	s_children;
35 	struct list_head	s_links;
36 	void			* s_element;
37 	int			s_type;
38 	umode_t			s_mode;
39 	struct dentry		* s_dentry;
40 	struct iattr		* s_iattr;
41 };
42 
43 #define CONFIGFS_ROOT		0x0001
44 #define CONFIGFS_DIR		0x0002
45 #define CONFIGFS_ITEM_ATTR	0x0004
46 #define CONFIGFS_ITEM_LINK	0x0020
47 #define CONFIGFS_USET_DIR	0x0040
48 #define CONFIGFS_USET_DEFAULT	0x0080
49 #define CONFIGFS_USET_DROPPING	0x0100
50 #define CONFIGFS_NOT_PINNED	(CONFIGFS_ITEM_ATTR)
51 
52 extern struct vfsmount * configfs_mount;
53 extern struct kmem_cache *configfs_dir_cachep;
54 
55 extern int configfs_is_root(struct config_item *item);
56 
57 extern struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent *);
58 extern int configfs_create(struct dentry *, int mode, int (*init)(struct inode *));
59 extern int configfs_inode_init(void);
60 extern void configfs_inode_exit(void);
61 
62 extern int configfs_create_file(struct config_item *, const struct configfs_attribute *);
63 extern int configfs_make_dirent(struct configfs_dirent *,
64 				struct dentry *, void *, umode_t, int);
65 
66 extern int configfs_add_file(struct dentry *, const struct configfs_attribute *, int);
67 extern void configfs_hash_and_remove(struct dentry * dir, const char * name);
68 
69 extern const unsigned char * configfs_get_name(struct configfs_dirent *sd);
70 extern void configfs_drop_dentry(struct configfs_dirent *sd, struct dentry *parent);
71 extern int configfs_setattr(struct dentry *dentry, struct iattr *iattr);
72 
73 extern int configfs_pin_fs(void);
74 extern void configfs_release_fs(void);
75 
76 extern struct rw_semaphore configfs_rename_sem;
77 extern struct super_block * configfs_sb;
78 extern const struct file_operations configfs_dir_operations;
79 extern const struct file_operations configfs_file_operations;
80 extern const struct file_operations bin_fops;
81 extern const struct inode_operations configfs_dir_inode_operations;
82 extern const struct inode_operations configfs_symlink_inode_operations;
83 
84 extern int configfs_symlink(struct inode *dir, struct dentry *dentry,
85 			    const char *symname);
86 extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
87 
88 struct configfs_symlink {
89 	struct list_head sl_list;
90 	struct config_item *sl_target;
91 };
92 
93 extern int configfs_create_link(struct configfs_symlink *sl,
94 				struct dentry *parent,
95 				struct dentry *dentry);
96 
97 static inline struct config_item * to_item(struct dentry * dentry)
98 {
99 	struct configfs_dirent * sd = dentry->d_fsdata;
100 	return ((struct config_item *) sd->s_element);
101 }
102 
103 static inline struct configfs_attribute * to_attr(struct dentry * dentry)
104 {
105 	struct configfs_dirent * sd = dentry->d_fsdata;
106 	return ((struct configfs_attribute *) sd->s_element);
107 }
108 
109 static inline struct config_item *configfs_get_config_item(struct dentry *dentry)
110 {
111 	struct config_item * item = NULL;
112 
113 	spin_lock(&dcache_lock);
114 	if (!d_unhashed(dentry)) {
115 		struct configfs_dirent * sd = dentry->d_fsdata;
116 		if (sd->s_type & CONFIGFS_ITEM_LINK) {
117 			struct configfs_symlink * sl = sd->s_element;
118 			item = config_item_get(sl->sl_target);
119 		} else
120 			item = config_item_get(sd->s_element);
121 	}
122 	spin_unlock(&dcache_lock);
123 
124 	return item;
125 }
126 
127 static inline void release_configfs_dirent(struct configfs_dirent * sd)
128 {
129 	if (!(sd->s_type & CONFIGFS_ROOT)) {
130 		kfree(sd->s_iattr);
131 		kmem_cache_free(configfs_dir_cachep, sd);
132 	}
133 }
134 
135 static inline struct configfs_dirent * configfs_get(struct configfs_dirent * sd)
136 {
137 	if (sd) {
138 		WARN_ON(!atomic_read(&sd->s_count));
139 		atomic_inc(&sd->s_count);
140 	}
141 	return sd;
142 }
143 
144 static inline void configfs_put(struct configfs_dirent * sd)
145 {
146 	WARN_ON(!atomic_read(&sd->s_count));
147 	if (atomic_dec_and_test(&sd->s_count))
148 		release_configfs_dirent(sd);
149 }
150 
151