[XFS] Fix race when looking up reclaimable inodes
[linux-2.6] / fs / gfs2 / eaops.c
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
4  *
5  * This copyrighted material is made available to anyone wishing to use,
6  * modify, copy, or redistribute it subject to the terms and conditions
7  * of the GNU General Public License version 2.
8  */
9
10 #include <linux/slab.h>
11 #include <linux/spinlock.h>
12 #include <linux/completion.h>
13 #include <linux/buffer_head.h>
14 #include <linux/capability.h>
15 #include <linux/xattr.h>
16 #include <linux/gfs2_ondisk.h>
17 #include <linux/lm_interface.h>
18 #include <asm/uaccess.h>
19
20 #include "gfs2.h"
21 #include "incore.h"
22 #include "acl.h"
23 #include "eaops.h"
24 #include "eattr.h"
25 #include "util.h"
26
27 /**
28  * gfs2_ea_name2type - get the type of the ea, and truncate type from the name
29  * @namep: ea name, possibly with type appended
30  *
31  * Returns: GFS2_EATYPE_XXX
32  */
33
34 unsigned int gfs2_ea_name2type(const char *name, const char **truncated_name)
35 {
36         unsigned int type;
37
38         if (strncmp(name, "system.", 7) == 0) {
39                 type = GFS2_EATYPE_SYS;
40                 if (truncated_name)
41                         *truncated_name = name + sizeof("system.") - 1;
42         } else if (strncmp(name, "user.", 5) == 0) {
43                 type = GFS2_EATYPE_USR;
44                 if (truncated_name)
45                         *truncated_name = name + sizeof("user.") - 1;
46         } else if (strncmp(name, "security.", 9) == 0) {
47                 type = GFS2_EATYPE_SECURITY;
48                 if (truncated_name)
49                         *truncated_name = name + sizeof("security.") - 1;
50         } else {
51                 type = GFS2_EATYPE_UNUSED;
52                 if (truncated_name)
53                         *truncated_name = NULL;
54         }
55
56         return type;
57 }
58
59 static int system_eo_get(struct gfs2_inode *ip, struct gfs2_ea_request *er)
60 {
61         if (!GFS2_ACL_IS_ACCESS(er->er_name, er->er_name_len) &&
62             !GFS2_ACL_IS_DEFAULT(er->er_name, er->er_name_len) &&
63             !capable(CAP_SYS_ADMIN))
64                 return -EPERM;
65
66         if (GFS2_SB(&ip->i_inode)->sd_args.ar_posix_acl == 0 &&
67             (GFS2_ACL_IS_ACCESS(er->er_name, er->er_name_len) ||
68              GFS2_ACL_IS_DEFAULT(er->er_name, er->er_name_len)))
69                 return -EOPNOTSUPP;
70
71         return gfs2_ea_get_i(ip, er);
72 }
73
74 static int system_eo_set(struct gfs2_inode *ip, struct gfs2_ea_request *er)
75 {
76         int remove = 0;
77         int error;
78
79         if (GFS2_ACL_IS_ACCESS(er->er_name, er->er_name_len)) {
80                 if (!(er->er_flags & GFS2_ERF_MODE)) {
81                         er->er_mode = ip->i_inode.i_mode;
82                         er->er_flags |= GFS2_ERF_MODE;
83                 }
84                 error = gfs2_acl_validate_set(ip, 1, er,
85                                               &remove, &er->er_mode);
86                 if (error)
87                         return error;
88                 error = gfs2_ea_set_i(ip, er);
89                 if (error)
90                         return error;
91                 if (remove)
92                         gfs2_ea_remove_i(ip, er);
93                 return 0;
94
95         } else if (GFS2_ACL_IS_DEFAULT(er->er_name, er->er_name_len)) {
96                 error = gfs2_acl_validate_set(ip, 0, er,
97                                               &remove, NULL);
98                 if (error)
99                         return error;
100                 if (!remove)
101                         error = gfs2_ea_set_i(ip, er);
102                 else {
103                         error = gfs2_ea_remove_i(ip, er);
104                         if (error == -ENODATA)
105                                 error = 0;
106                 }
107                 return error;
108         }
109
110         return -EPERM;
111 }
112
113 static int system_eo_remove(struct gfs2_inode *ip, struct gfs2_ea_request *er)
114 {
115         if (GFS2_ACL_IS_ACCESS(er->er_name, er->er_name_len)) {
116                 int error = gfs2_acl_validate_remove(ip, 1);
117                 if (error)
118                         return error;
119
120         } else if (GFS2_ACL_IS_DEFAULT(er->er_name, er->er_name_len)) {
121                 int error = gfs2_acl_validate_remove(ip, 0);
122                 if (error)
123                         return error;
124
125         } else
126                 return -EPERM;
127
128         return gfs2_ea_remove_i(ip, er);
129 }
130
131 static const struct gfs2_eattr_operations gfs2_user_eaops = {
132         .eo_get = gfs2_ea_get_i,
133         .eo_set = gfs2_ea_set_i,
134         .eo_remove = gfs2_ea_remove_i,
135         .eo_name = "user",
136 };
137
138 const struct gfs2_eattr_operations gfs2_system_eaops = {
139         .eo_get = system_eo_get,
140         .eo_set = system_eo_set,
141         .eo_remove = system_eo_remove,
142         .eo_name = "system",
143 };
144
145 static const struct gfs2_eattr_operations gfs2_security_eaops = {
146         .eo_get = gfs2_ea_get_i,
147         .eo_set = gfs2_ea_set_i,
148         .eo_remove = gfs2_ea_remove_i,
149         .eo_name = "security",
150 };
151
152 const struct gfs2_eattr_operations *gfs2_ea_ops[] = {
153         NULL,
154         &gfs2_user_eaops,
155         &gfs2_system_eaops,
156         &gfs2_security_eaops,
157 };
158