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328970de | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
fa60ce2c | 2 | /* |
7063fbf2 JB |
3 | * inode.c - basic inode and dentry operations. |
4 | * | |
7063fbf2 JB |
5 | * Based on sysfs: |
6 | * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel | |
7 | * | |
8 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
9 | * | |
98264991 | 10 | * Please see Documentation/filesystems/configfs.rst for more |
395cf969 | 11 | * information. |
7063fbf2 JB |
12 | */ |
13 | ||
14 | #undef DEBUG | |
15 | ||
16 | #include <linux/pagemap.h> | |
17 | #include <linux/namei.h> | |
18 | #include <linux/backing-dev.h> | |
3d0f89bb | 19 | #include <linux/capability.h> |
e8edc6e0 | 20 | #include <linux/sched.h> |
e74cc06d | 21 | #include <linux/lockdep.h> |
5a0e3ad6 | 22 | #include <linux/slab.h> |
7063fbf2 JB |
23 | |
24 | #include <linux/configfs.h> | |
25 | #include "configfs_internal.h" | |
26 | ||
e74cc06d LR |
27 | #ifdef CONFIG_LOCKDEP |
28 | static struct lock_class_key default_group_class[MAX_LOCK_DEPTH]; | |
29 | #endif | |
30 | ||
754661f1 | 31 | static const struct inode_operations configfs_inode_operations ={ |
3d0f89bb JB |
32 | .setattr = configfs_setattr, |
33 | }; | |
34 | ||
c1632a0f | 35 | int configfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry, |
549c7297 | 36 | struct iattr *iattr) |
3d0f89bb | 37 | { |
2b0143b5 | 38 | struct inode * inode = d_inode(dentry); |
3d0f89bb JB |
39 | struct configfs_dirent * sd = dentry->d_fsdata; |
40 | struct iattr * sd_iattr; | |
41 | unsigned int ia_valid = iattr->ia_valid; | |
42 | int error; | |
43 | ||
44 | if (!sd) | |
45 | return -EINVAL; | |
46 | ||
3322e79a | 47 | sd_iattr = sd->s_iattr; |
3d0f89bb JB |
48 | if (!sd_iattr) { |
49 | /* setting attributes for the first time, allocate now */ | |
f8314dc6 | 50 | sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); |
3d0f89bb JB |
51 | if (!sd_iattr) |
52 | return -ENOMEM; | |
53 | /* assign default attributes */ | |
3d0f89bb | 54 | sd_iattr->ia_mode = sd->s_mode; |
69552c0c EB |
55 | sd_iattr->ia_uid = GLOBAL_ROOT_UID; |
56 | sd_iattr->ia_gid = GLOBAL_ROOT_GID; | |
b1f1a29d | 57 | sd_iattr->ia_atime = sd_iattr->ia_mtime = |
c2050a45 | 58 | sd_iattr->ia_ctime = current_time(inode); |
3d0f89bb JB |
59 | sd->s_iattr = sd_iattr; |
60 | } | |
3d0f89bb JB |
61 | /* attributes were changed atleast once in past */ |
62 | ||
c1632a0f | 63 | error = simple_setattr(idmap, dentry, iattr); |
75de46b9 NP |
64 | if (error) |
65 | return error; | |
66 | ||
3d0f89bb JB |
67 | if (ia_valid & ATTR_UID) |
68 | sd_iattr->ia_uid = iattr->ia_uid; | |
69 | if (ia_valid & ATTR_GID) | |
70 | sd_iattr->ia_gid = iattr->ia_gid; | |
71 | if (ia_valid & ATTR_ATIME) | |
eb31e2f6 | 72 | sd_iattr->ia_atime = iattr->ia_atime; |
3d0f89bb | 73 | if (ia_valid & ATTR_MTIME) |
eb31e2f6 | 74 | sd_iattr->ia_mtime = iattr->ia_mtime; |
3d0f89bb | 75 | if (ia_valid & ATTR_CTIME) |
eb31e2f6 | 76 | sd_iattr->ia_ctime = iattr->ia_ctime; |
3d0f89bb JB |
77 | if (ia_valid & ATTR_MODE) { |
78 | umode_t mode = iattr->ia_mode; | |
79 | ||
80 | if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) | |
81 | mode &= ~S_ISGID; | |
82 | sd_iattr->ia_mode = sd->s_mode = mode; | |
83 | } | |
84 | ||
85 | return error; | |
86 | } | |
87 | ||
43947514 | 88 | static inline void set_default_inode_attr(struct inode * inode, umode_t mode) |
3d0f89bb JB |
89 | { |
90 | inode->i_mode = mode; | |
b1f1a29d | 91 | inode->i_atime = inode->i_mtime = |
c2050a45 | 92 | inode->i_ctime = current_time(inode); |
3d0f89bb JB |
93 | } |
94 | ||
95 | static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) | |
96 | { | |
97 | inode->i_mode = iattr->ia_mode; | |
98 | inode->i_uid = iattr->ia_uid; | |
99 | inode->i_gid = iattr->ia_gid; | |
100 | inode->i_atime = iattr->ia_atime; | |
101 | inode->i_mtime = iattr->ia_mtime; | |
102 | inode->i_ctime = iattr->ia_ctime; | |
103 | } | |
104 | ||
b7c177fc AV |
105 | struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd, |
106 | struct super_block *s) | |
7063fbf2 | 107 | { |
b7c177fc | 108 | struct inode * inode = new_inode(s); |
7063fbf2 | 109 | if (inode) { |
85fe4025 | 110 | inode->i_ino = get_next_ino(); |
c1e3dbe9 | 111 | inode->i_mapping->a_ops = &ram_aops; |
3d0f89bb JB |
112 | inode->i_op = &configfs_inode_operations; |
113 | ||
114 | if (sd->s_iattr) { | |
115 | /* sysfs_dirent has non-default attributes | |
116 | * get them for the new inode from persistent copy | |
117 | * in sysfs_dirent | |
118 | */ | |
119 | set_inode_attr(inode, sd->s_iattr); | |
120 | } else | |
121 | set_default_inode_attr(inode, mode); | |
7063fbf2 JB |
122 | } |
123 | return inode; | |
124 | } | |
125 | ||
e74cc06d LR |
126 | #ifdef CONFIG_LOCKDEP |
127 | ||
128 | static void configfs_set_inode_lock_class(struct configfs_dirent *sd, | |
129 | struct inode *inode) | |
130 | { | |
131 | int depth = sd->s_depth; | |
132 | ||
133 | if (depth > 0) { | |
134 | if (depth <= ARRAY_SIZE(default_group_class)) { | |
9902af79 | 135 | lockdep_set_class(&inode->i_rwsem, |
e74cc06d LR |
136 | &default_group_class[depth - 1]); |
137 | } else { | |
138 | /* | |
139 | * In practice the maximum level of locking depth is | |
140 | * already reached. Just inform about possible reasons. | |
141 | */ | |
1d88aa44 | 142 | pr_info("Too many levels of inodes for the locking correctness validator.\n"); |
c6686931 | 143 | pr_info("Spurious warnings may appear.\n"); |
e74cc06d LR |
144 | } |
145 | } | |
146 | } | |
147 | ||
148 | #else /* CONFIG_LOCKDEP */ | |
149 | ||
150 | static void configfs_set_inode_lock_class(struct configfs_dirent *sd, | |
151 | struct inode *inode) | |
152 | { | |
153 | } | |
154 | ||
155 | #endif /* CONFIG_LOCKDEP */ | |
156 | ||
2743c515 | 157 | struct inode *configfs_create(struct dentry *dentry, umode_t mode) |
7063fbf2 | 158 | { |
16d13b59 AV |
159 | struct inode *inode = NULL; |
160 | struct configfs_dirent *sd; | |
161 | struct inode *p_inode; | |
162 | ||
163 | if (!dentry) | |
2743c515 | 164 | return ERR_PTR(-ENOENT); |
16d13b59 | 165 | |
2b0143b5 | 166 | if (d_really_is_positive(dentry)) |
2743c515 | 167 | return ERR_PTR(-EEXIST); |
7063fbf2 | 168 | |
16d13b59 AV |
169 | sd = dentry->d_fsdata; |
170 | inode = configfs_new_inode(mode, sd, dentry->d_sb); | |
171 | if (!inode) | |
2743c515 | 172 | return ERR_PTR(-ENOMEM); |
16d13b59 | 173 | |
2b0143b5 | 174 | p_inode = d_inode(dentry->d_parent); |
c2050a45 | 175 | p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode); |
16d13b59 | 176 | configfs_set_inode_lock_class(sd, inode); |
2743c515 | 177 | return inode; |
7063fbf2 JB |
178 | } |
179 | ||
180 | /* | |
181 | * Get the name for corresponding element represented by the given configfs_dirent | |
182 | */ | |
183 | const unsigned char * configfs_get_name(struct configfs_dirent *sd) | |
184 | { | |
3d0f89bb | 185 | struct configfs_attribute *attr; |
7063fbf2 | 186 | |
1a1974fd | 187 | BUG_ON(!sd || !sd->s_element); |
7063fbf2 JB |
188 | |
189 | /* These always have a dentry, so use that */ | |
190 | if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) | |
191 | return sd->s_dentry->d_name.name; | |
192 | ||
03607ace | 193 | if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) { |
7063fbf2 | 194 | attr = sd->s_element; |
3d0f89bb | 195 | return attr->ca_name; |
7063fbf2 JB |
196 | } |
197 | return NULL; | |
198 | } | |
199 | ||
200 | ||
201 | /* | |
202 | * Unhashes the dentry corresponding to given configfs_dirent | |
1b1dcc1b | 203 | * Called with parent inode's i_mutex held. |
7063fbf2 JB |
204 | */ |
205 | void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) | |
206 | { | |
207 | struct dentry * dentry = sd->s_dentry; | |
208 | ||
209 | if (dentry) { | |
3d0f89bb | 210 | spin_lock(&dentry->d_lock); |
dc3f4198 | 211 | if (simple_positive(dentry)) { |
dc0474be | 212 | dget_dlock(dentry); |
7063fbf2 | 213 | __d_drop(dentry); |
3d0f89bb | 214 | spin_unlock(&dentry->d_lock); |
2b0143b5 | 215 | simple_unlink(d_inode(parent), dentry); |
b5c84bf6 | 216 | } else |
3d0f89bb | 217 | spin_unlock(&dentry->d_lock); |
7063fbf2 JB |
218 | } |
219 | } | |
220 | ||
221 | void configfs_hash_and_remove(struct dentry * dir, const char * name) | |
222 | { | |
223 | struct configfs_dirent * sd; | |
224 | struct configfs_dirent * parent_sd = dir->d_fsdata; | |
225 | ||
2b0143b5 | 226 | if (d_really_is_negative(dir)) |
3d0f89bb JB |
227 | /* no inode means this hasn't been made visible yet */ |
228 | return; | |
229 | ||
5955102c | 230 | inode_lock(d_inode(dir)); |
7063fbf2 JB |
231 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
232 | if (!sd->s_element) | |
233 | continue; | |
234 | if (!strcmp(configfs_get_name(sd), name)) { | |
6f610764 | 235 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 236 | list_del_init(&sd->s_sibling); |
6f610764 | 237 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
238 | configfs_drop_dentry(sd, dir); |
239 | configfs_put(sd); | |
240 | break; | |
241 | } | |
242 | } | |
5955102c | 243 | inode_unlock(d_inode(dir)); |
7063fbf2 | 244 | } |