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7063fbf2 JB |
1 | /* -*- mode: c; c-basic-offset: 8; -*- |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
3 | * | |
4 | * inode.c - basic inode and dentry operations. | |
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 | * | |
395cf969 PB |
26 | * Please see Documentation/filesystems/configfs/configfs.txt for more |
27 | * information. | |
7063fbf2 JB |
28 | */ |
29 | ||
30 | #undef DEBUG | |
31 | ||
32 | #include <linux/pagemap.h> | |
33 | #include <linux/namei.h> | |
34 | #include <linux/backing-dev.h> | |
3d0f89bb | 35 | #include <linux/capability.h> |
e8edc6e0 | 36 | #include <linux/sched.h> |
e74cc06d | 37 | #include <linux/lockdep.h> |
5a0e3ad6 | 38 | #include <linux/slab.h> |
7063fbf2 JB |
39 | |
40 | #include <linux/configfs.h> | |
41 | #include "configfs_internal.h" | |
42 | ||
e74cc06d LR |
43 | #ifdef CONFIG_LOCKDEP |
44 | static struct lock_class_key default_group_class[MAX_LOCK_DEPTH]; | |
45 | #endif | |
46 | ||
f5e54d6e | 47 | static const struct address_space_operations configfs_aops = { |
7063fbf2 | 48 | .readpage = simple_readpage, |
800d15a5 NP |
49 | .write_begin = simple_write_begin, |
50 | .write_end = simple_write_end, | |
7063fbf2 JB |
51 | }; |
52 | ||
754661f1 | 53 | static const struct inode_operations configfs_inode_operations ={ |
3d0f89bb JB |
54 | .setattr = configfs_setattr, |
55 | }; | |
56 | ||
57 | int configfs_setattr(struct dentry * dentry, struct iattr * iattr) | |
58 | { | |
2b0143b5 | 59 | struct inode * inode = d_inode(dentry); |
3d0f89bb JB |
60 | struct configfs_dirent * sd = dentry->d_fsdata; |
61 | struct iattr * sd_iattr; | |
62 | unsigned int ia_valid = iattr->ia_valid; | |
63 | int error; | |
64 | ||
65 | if (!sd) | |
66 | return -EINVAL; | |
67 | ||
3322e79a | 68 | sd_iattr = sd->s_iattr; |
3d0f89bb JB |
69 | if (!sd_iattr) { |
70 | /* setting attributes for the first time, allocate now */ | |
f8314dc6 | 71 | sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); |
3d0f89bb JB |
72 | if (!sd_iattr) |
73 | return -ENOMEM; | |
74 | /* assign default attributes */ | |
3d0f89bb | 75 | sd_iattr->ia_mode = sd->s_mode; |
69552c0c EB |
76 | sd_iattr->ia_uid = GLOBAL_ROOT_UID; |
77 | sd_iattr->ia_gid = GLOBAL_ROOT_GID; | |
3d0f89bb JB |
78 | sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME; |
79 | sd->s_iattr = sd_iattr; | |
80 | } | |
3d0f89bb JB |
81 | /* attributes were changed atleast once in past */ |
82 | ||
75de46b9 NP |
83 | error = simple_setattr(dentry, iattr); |
84 | if (error) | |
85 | return error; | |
86 | ||
3d0f89bb JB |
87 | if (ia_valid & ATTR_UID) |
88 | sd_iattr->ia_uid = iattr->ia_uid; | |
89 | if (ia_valid & ATTR_GID) | |
90 | sd_iattr->ia_gid = iattr->ia_gid; | |
91 | if (ia_valid & ATTR_ATIME) | |
92 | sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime, | |
93 | inode->i_sb->s_time_gran); | |
94 | if (ia_valid & ATTR_MTIME) | |
95 | sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime, | |
96 | inode->i_sb->s_time_gran); | |
97 | if (ia_valid & ATTR_CTIME) | |
98 | sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime, | |
99 | inode->i_sb->s_time_gran); | |
100 | if (ia_valid & ATTR_MODE) { | |
101 | umode_t mode = iattr->ia_mode; | |
102 | ||
103 | if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) | |
104 | mode &= ~S_ISGID; | |
105 | sd_iattr->ia_mode = sd->s_mode = mode; | |
106 | } | |
107 | ||
108 | return error; | |
109 | } | |
110 | ||
43947514 | 111 | static inline void set_default_inode_attr(struct inode * inode, umode_t mode) |
3d0f89bb JB |
112 | { |
113 | inode->i_mode = mode; | |
3d0f89bb JB |
114 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
115 | } | |
116 | ||
117 | static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) | |
118 | { | |
119 | inode->i_mode = iattr->ia_mode; | |
120 | inode->i_uid = iattr->ia_uid; | |
121 | inode->i_gid = iattr->ia_gid; | |
122 | inode->i_atime = iattr->ia_atime; | |
123 | inode->i_mtime = iattr->ia_mtime; | |
124 | inode->i_ctime = iattr->ia_ctime; | |
125 | } | |
126 | ||
b7c177fc AV |
127 | struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd, |
128 | struct super_block *s) | |
7063fbf2 | 129 | { |
b7c177fc | 130 | struct inode * inode = new_inode(s); |
7063fbf2 | 131 | if (inode) { |
85fe4025 | 132 | inode->i_ino = get_next_ino(); |
7063fbf2 | 133 | inode->i_mapping->a_ops = &configfs_aops; |
3d0f89bb JB |
134 | inode->i_op = &configfs_inode_operations; |
135 | ||
136 | if (sd->s_iattr) { | |
137 | /* sysfs_dirent has non-default attributes | |
138 | * get them for the new inode from persistent copy | |
139 | * in sysfs_dirent | |
140 | */ | |
141 | set_inode_attr(inode, sd->s_iattr); | |
142 | } else | |
143 | set_default_inode_attr(inode, mode); | |
7063fbf2 JB |
144 | } |
145 | return inode; | |
146 | } | |
147 | ||
e74cc06d LR |
148 | #ifdef CONFIG_LOCKDEP |
149 | ||
150 | static void configfs_set_inode_lock_class(struct configfs_dirent *sd, | |
151 | struct inode *inode) | |
152 | { | |
153 | int depth = sd->s_depth; | |
154 | ||
155 | if (depth > 0) { | |
156 | if (depth <= ARRAY_SIZE(default_group_class)) { | |
157 | lockdep_set_class(&inode->i_mutex, | |
158 | &default_group_class[depth - 1]); | |
159 | } else { | |
160 | /* | |
161 | * In practice the maximum level of locking depth is | |
162 | * already reached. Just inform about possible reasons. | |
163 | */ | |
1d88aa44 | 164 | pr_info("Too many levels of inodes for the locking correctness validator.\n"); |
c6686931 | 165 | pr_info("Spurious warnings may appear.\n"); |
e74cc06d LR |
166 | } |
167 | } | |
168 | } | |
169 | ||
170 | #else /* CONFIG_LOCKDEP */ | |
171 | ||
172 | static void configfs_set_inode_lock_class(struct configfs_dirent *sd, | |
173 | struct inode *inode) | |
174 | { | |
175 | } | |
176 | ||
177 | #endif /* CONFIG_LOCKDEP */ | |
178 | ||
c88b1e70 | 179 | int configfs_create(struct dentry * dentry, umode_t mode, void (*init)(struct inode *)) |
7063fbf2 JB |
180 | { |
181 | int error = 0; | |
16d13b59 AV |
182 | struct inode *inode = NULL; |
183 | struct configfs_dirent *sd; | |
184 | struct inode *p_inode; | |
185 | ||
186 | if (!dentry) | |
187 | return -ENOENT; | |
188 | ||
2b0143b5 | 189 | if (d_really_is_positive(dentry)) |
16d13b59 | 190 | return -EEXIST; |
7063fbf2 | 191 | |
16d13b59 AV |
192 | sd = dentry->d_fsdata; |
193 | inode = configfs_new_inode(mode, sd, dentry->d_sb); | |
194 | if (!inode) | |
195 | return -ENOMEM; | |
196 | ||
2b0143b5 | 197 | p_inode = d_inode(dentry->d_parent); |
16d13b59 AV |
198 | p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; |
199 | configfs_set_inode_lock_class(sd, inode); | |
200 | ||
c88b1e70 | 201 | init(inode); |
16d13b59 AV |
202 | d_instantiate(dentry, inode); |
203 | if (S_ISDIR(mode) || S_ISLNK(mode)) | |
204 | dget(dentry); /* pin link and directory dentries in core */ | |
7063fbf2 JB |
205 | return error; |
206 | } | |
207 | ||
208 | /* | |
209 | * Get the name for corresponding element represented by the given configfs_dirent | |
210 | */ | |
211 | const unsigned char * configfs_get_name(struct configfs_dirent *sd) | |
212 | { | |
3d0f89bb | 213 | struct configfs_attribute *attr; |
7063fbf2 | 214 | |
1a1974fd | 215 | BUG_ON(!sd || !sd->s_element); |
7063fbf2 JB |
216 | |
217 | /* These always have a dentry, so use that */ | |
218 | if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) | |
219 | return sd->s_dentry->d_name.name; | |
220 | ||
221 | if (sd->s_type & CONFIGFS_ITEM_ATTR) { | |
222 | attr = sd->s_element; | |
3d0f89bb | 223 | return attr->ca_name; |
7063fbf2 JB |
224 | } |
225 | return NULL; | |
226 | } | |
227 | ||
228 | ||
229 | /* | |
230 | * Unhashes the dentry corresponding to given configfs_dirent | |
1b1dcc1b | 231 | * Called with parent inode's i_mutex held. |
7063fbf2 JB |
232 | */ |
233 | void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) | |
234 | { | |
235 | struct dentry * dentry = sd->s_dentry; | |
236 | ||
237 | if (dentry) { | |
3d0f89bb | 238 | spin_lock(&dentry->d_lock); |
2b0143b5 | 239 | if (!d_unhashed(dentry) && d_really_is_positive(dentry)) { |
dc0474be | 240 | dget_dlock(dentry); |
7063fbf2 | 241 | __d_drop(dentry); |
3d0f89bb | 242 | spin_unlock(&dentry->d_lock); |
2b0143b5 | 243 | simple_unlink(d_inode(parent), dentry); |
b5c84bf6 | 244 | } else |
3d0f89bb | 245 | spin_unlock(&dentry->d_lock); |
7063fbf2 JB |
246 | } |
247 | } | |
248 | ||
249 | void configfs_hash_and_remove(struct dentry * dir, const char * name) | |
250 | { | |
251 | struct configfs_dirent * sd; | |
252 | struct configfs_dirent * parent_sd = dir->d_fsdata; | |
253 | ||
2b0143b5 | 254 | if (d_really_is_negative(dir)) |
3d0f89bb JB |
255 | /* no inode means this hasn't been made visible yet */ |
256 | return; | |
257 | ||
2b0143b5 | 258 | mutex_lock(&d_inode(dir)->i_mutex); |
7063fbf2 JB |
259 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
260 | if (!sd->s_element) | |
261 | continue; | |
262 | if (!strcmp(configfs_get_name(sd), name)) { | |
6f610764 | 263 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 264 | list_del_init(&sd->s_sibling); |
6f610764 | 265 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
266 | configfs_drop_dentry(sd, dir); |
267 | configfs_put(sd); | |
268 | break; | |
269 | } | |
270 | } | |
2b0143b5 | 271 | mutex_unlock(&d_inode(dir)->i_mutex); |
7063fbf2 | 272 | } |