mmc: core: SDXC speed class support
[linux-2.6.git] / include / linux / posix_acl.h
1 /*
2   File: linux/posix_acl.h
3
4   (C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
5 */
6
7
8 #ifndef __LINUX_POSIX_ACL_H
9 #define __LINUX_POSIX_ACL_H
10
11 #include <linux/slab.h>
12 #include <linux/rcupdate.h>
13
14 #define ACL_UNDEFINED_ID        (-1)
15
16 /* a_type field in acl_user_posix_entry_t */
17 #define ACL_TYPE_ACCESS         (0x8000)
18 #define ACL_TYPE_DEFAULT        (0x4000)
19
20 /* e_tag entry in struct posix_acl_entry */
21 #define ACL_USER_OBJ            (0x01)
22 #define ACL_USER                (0x02)
23 #define ACL_GROUP_OBJ           (0x04)
24 #define ACL_GROUP               (0x08)
25 #define ACL_MASK                (0x10)
26 #define ACL_OTHER               (0x20)
27
28 /* permissions in the e_perm field */
29 #define ACL_READ                (0x04)
30 #define ACL_WRITE               (0x02)
31 #define ACL_EXECUTE             (0x01)
32 //#define ACL_ADD               (0x08)
33 //#define ACL_DELETE            (0x10)
34
35 struct posix_acl_entry {
36         short                   e_tag;
37         unsigned short          e_perm;
38         unsigned int            e_id;
39 };
40
41 struct posix_acl {
42         union {
43                 atomic_t                a_refcount;
44                 struct rcu_head         a_rcu;
45         };
46         unsigned int            a_count;
47         struct posix_acl_entry  a_entries[0];
48 };
49
50 #define FOREACH_ACL_ENTRY(pa, acl, pe) \
51         for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
52
53
54 /*
55  * Duplicate an ACL handle.
56  */
57 static inline struct posix_acl *
58 posix_acl_dup(struct posix_acl *acl)
59 {
60         if (acl)
61                 atomic_inc(&acl->a_refcount);
62         return acl;
63 }
64
65 /*
66  * Free an ACL handle.
67  */
68 static inline void
69 posix_acl_release(struct posix_acl *acl)
70 {
71         if (acl && atomic_dec_and_test(&acl->a_refcount))
72                 kfree_rcu(acl, a_rcu);
73 }
74
75
76 /* posix_acl.c */
77
78 extern void posix_acl_init(struct posix_acl *, int);
79 extern struct posix_acl *posix_acl_alloc(int, gfp_t);
80 extern int posix_acl_valid(const struct posix_acl *);
81 extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
82 extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
83 extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
84 extern int posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
85 extern int posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
86
87 extern struct posix_acl *get_posix_acl(struct inode *, int);
88 extern int set_posix_acl(struct inode *, int, struct posix_acl *);
89
90 #ifdef CONFIG_FS_POSIX_ACL
91 static inline struct posix_acl **acl_by_type(struct inode *inode, int type)
92 {
93         switch (type) {
94         case ACL_TYPE_ACCESS:
95                 return &inode->i_acl;
96         case ACL_TYPE_DEFAULT:
97                 return &inode->i_default_acl;
98         default:
99                 BUG();
100         }
101 }
102
103 static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
104 {
105         struct posix_acl **p = acl_by_type(inode, type);
106         struct posix_acl *acl = ACCESS_ONCE(*p);
107         if (acl) {
108                 spin_lock(&inode->i_lock);
109                 acl = *p;
110                 if (acl != ACL_NOT_CACHED)
111                         acl = posix_acl_dup(acl);
112                 spin_unlock(&inode->i_lock);
113         }
114         return acl;
115 }
116
117 static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
118 {
119         return rcu_dereference(*acl_by_type(inode, type));
120 }
121
122 static inline void set_cached_acl(struct inode *inode,
123                                   int type,
124                                   struct posix_acl *acl)
125 {
126         struct posix_acl **p = acl_by_type(inode, type);
127         struct posix_acl *old;
128         spin_lock(&inode->i_lock);
129         old = *p;
130         rcu_assign_pointer(*p, posix_acl_dup(acl));
131         spin_unlock(&inode->i_lock);
132         if (old != ACL_NOT_CACHED)
133                 posix_acl_release(old);
134 }
135
136 static inline void forget_cached_acl(struct inode *inode, int type)
137 {
138         struct posix_acl **p = acl_by_type(inode, type);
139         struct posix_acl *old;
140         spin_lock(&inode->i_lock);
141         old = *p;
142         *p = ACL_NOT_CACHED;
143         spin_unlock(&inode->i_lock);
144         if (old != ACL_NOT_CACHED)
145                 posix_acl_release(old);
146 }
147
148 static inline void forget_all_cached_acls(struct inode *inode)
149 {
150         struct posix_acl *old_access, *old_default;
151         spin_lock(&inode->i_lock);
152         old_access = inode->i_acl;
153         old_default = inode->i_default_acl;
154         inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
155         spin_unlock(&inode->i_lock);
156         if (old_access != ACL_NOT_CACHED)
157                 posix_acl_release(old_access);
158         if (old_default != ACL_NOT_CACHED)
159                 posix_acl_release(old_default);
160 }
161 #endif
162
163 static inline void cache_no_acl(struct inode *inode)
164 {
165 #ifdef CONFIG_FS_POSIX_ACL
166         inode->i_acl = NULL;
167         inode->i_default_acl = NULL;
168 #endif
169 }
170
171 #endif  /* __LINUX_POSIX_ACL_H */