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328970de | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
7063fbf2 JB |
2 | /* -*- mode: c; c-basic-offset: 8; -*- |
3 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
4 | * | |
5 | * inode.c - basic inode and dentry operations. | |
6 | * | |
7063fbf2 JB |
7 | * Based on sysfs: |
8 | * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel | |
9 | * | |
10 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
11 | * | |
98264991 | 12 | * Please see Documentation/filesystems/configfs.rst for more |
395cf969 | 13 | * information. |
7063fbf2 JB |
14 | */ |
15 | ||
16 | #undef DEBUG | |
17 | ||
18 | #include <linux/pagemap.h> | |
19 | #include <linux/namei.h> | |
20 | #include <linux/backing-dev.h> | |
3d0f89bb | 21 | #include <linux/capability.h> |
e8edc6e0 | 22 | #include <linux/sched.h> |
e74cc06d | 23 | #include <linux/lockdep.h> |
5a0e3ad6 | 24 | #include <linux/slab.h> |
7063fbf2 JB |
25 | |
26 | #include <linux/configfs.h> | |
27 | #include "configfs_internal.h" | |
28 | ||
e74cc06d LR |
29 | #ifdef CONFIG_LOCKDEP |
30 | static struct lock_class_key default_group_class[MAX_LOCK_DEPTH]; | |
31 | #endif | |
32 | ||
f5e54d6e | 33 | static const struct address_space_operations configfs_aops = { |
7063fbf2 | 34 | .readpage = simple_readpage, |
800d15a5 NP |
35 | .write_begin = simple_write_begin, |
36 | .write_end = simple_write_end, | |
7063fbf2 JB |
37 | }; |
38 | ||
754661f1 | 39 | static const struct inode_operations configfs_inode_operations ={ |
3d0f89bb JB |
40 | .setattr = configfs_setattr, |
41 | }; | |
42 | ||
549c7297 CB |
43 | int configfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, |
44 | struct iattr *iattr) | |
3d0f89bb | 45 | { |
2b0143b5 | 46 | struct inode * inode = d_inode(dentry); |
3d0f89bb JB |
47 | struct configfs_dirent * sd = dentry->d_fsdata; |
48 | struct iattr * sd_iattr; | |
49 | unsigned int ia_valid = iattr->ia_valid; | |
50 | int error; | |
51 | ||
52 | if (!sd) | |
53 | return -EINVAL; | |
54 | ||
3322e79a | 55 | sd_iattr = sd->s_iattr; |
3d0f89bb JB |
56 | if (!sd_iattr) { |
57 | /* setting attributes for the first time, allocate now */ | |
f8314dc6 | 58 | sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); |
3d0f89bb JB |
59 | if (!sd_iattr) |
60 | return -ENOMEM; | |
61 | /* assign default attributes */ | |
3d0f89bb | 62 | sd_iattr->ia_mode = sd->s_mode; |
69552c0c EB |
63 | sd_iattr->ia_uid = GLOBAL_ROOT_UID; |
64 | sd_iattr->ia_gid = GLOBAL_ROOT_GID; | |
b1f1a29d | 65 | sd_iattr->ia_atime = sd_iattr->ia_mtime = |
c2050a45 | 66 | sd_iattr->ia_ctime = current_time(inode); |
3d0f89bb JB |
67 | sd->s_iattr = sd_iattr; |
68 | } | |
3d0f89bb JB |
69 | /* attributes were changed atleast once in past */ |
70 | ||
549c7297 | 71 | error = simple_setattr(mnt_userns, dentry, iattr); |
75de46b9 NP |
72 | if (error) |
73 | return error; | |
74 | ||
3d0f89bb JB |
75 | if (ia_valid & ATTR_UID) |
76 | sd_iattr->ia_uid = iattr->ia_uid; | |
77 | if (ia_valid & ATTR_GID) | |
78 | sd_iattr->ia_gid = iattr->ia_gid; | |
79 | if (ia_valid & ATTR_ATIME) | |
eb31e2f6 | 80 | sd_iattr->ia_atime = iattr->ia_atime; |
3d0f89bb | 81 | if (ia_valid & ATTR_MTIME) |
eb31e2f6 | 82 | sd_iattr->ia_mtime = iattr->ia_mtime; |
3d0f89bb | 83 | if (ia_valid & ATTR_CTIME) |
eb31e2f6 | 84 | sd_iattr->ia_ctime = iattr->ia_ctime; |
3d0f89bb JB |
85 | if (ia_valid & ATTR_MODE) { |
86 | umode_t mode = iattr->ia_mode; | |
87 | ||
88 | if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) | |
89 | mode &= ~S_ISGID; | |
90 | sd_iattr->ia_mode = sd->s_mode = mode; | |
91 | } | |
92 | ||
93 | return error; | |
94 | } | |
95 | ||
43947514 | 96 | static inline void set_default_inode_attr(struct inode * inode, umode_t mode) |
3d0f89bb JB |
97 | { |
98 | inode->i_mode = mode; | |
b1f1a29d | 99 | inode->i_atime = inode->i_mtime = |
c2050a45 | 100 | inode->i_ctime = current_time(inode); |
3d0f89bb JB |
101 | } |
102 | ||
103 | static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) | |
104 | { | |
105 | inode->i_mode = iattr->ia_mode; | |
106 | inode->i_uid = iattr->ia_uid; | |
107 | inode->i_gid = iattr->ia_gid; | |
108 | inode->i_atime = iattr->ia_atime; | |
109 | inode->i_mtime = iattr->ia_mtime; | |
110 | inode->i_ctime = iattr->ia_ctime; | |
111 | } | |
112 | ||
b7c177fc AV |
113 | struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd, |
114 | struct super_block *s) | |
7063fbf2 | 115 | { |
b7c177fc | 116 | struct inode * inode = new_inode(s); |
7063fbf2 | 117 | if (inode) { |
85fe4025 | 118 | inode->i_ino = get_next_ino(); |
7063fbf2 | 119 | inode->i_mapping->a_ops = &configfs_aops; |
3d0f89bb JB |
120 | inode->i_op = &configfs_inode_operations; |
121 | ||
122 | if (sd->s_iattr) { | |
123 | /* sysfs_dirent has non-default attributes | |
124 | * get them for the new inode from persistent copy | |
125 | * in sysfs_dirent | |
126 | */ | |
127 | set_inode_attr(inode, sd->s_iattr); | |
128 | } else | |
129 | set_default_inode_attr(inode, mode); | |
7063fbf2 JB |
130 | } |
131 | return inode; | |
132 | } | |
133 | ||
e74cc06d LR |
134 | #ifdef CONFIG_LOCKDEP |
135 | ||
136 | static void configfs_set_inode_lock_class(struct configfs_dirent *sd, | |
137 | struct inode *inode) | |
138 | { | |
139 | int depth = sd->s_depth; | |
140 | ||
141 | if (depth > 0) { | |
142 | if (depth <= ARRAY_SIZE(default_group_class)) { | |
9902af79 | 143 | lockdep_set_class(&inode->i_rwsem, |
e74cc06d LR |
144 | &default_group_class[depth - 1]); |
145 | } else { | |
146 | /* | |
147 | * In practice the maximum level of locking depth is | |
148 | * already reached. Just inform about possible reasons. | |
149 | */ | |
1d88aa44 | 150 | pr_info("Too many levels of inodes for the locking correctness validator.\n"); |
c6686931 | 151 | pr_info("Spurious warnings may appear.\n"); |
e74cc06d LR |
152 | } |
153 | } | |
154 | } | |
155 | ||
156 | #else /* CONFIG_LOCKDEP */ | |
157 | ||
158 | static void configfs_set_inode_lock_class(struct configfs_dirent *sd, | |
159 | struct inode *inode) | |
160 | { | |
161 | } | |
162 | ||
163 | #endif /* CONFIG_LOCKDEP */ | |
164 | ||
2743c515 | 165 | struct inode *configfs_create(struct dentry *dentry, umode_t mode) |
7063fbf2 | 166 | { |
16d13b59 AV |
167 | struct inode *inode = NULL; |
168 | struct configfs_dirent *sd; | |
169 | struct inode *p_inode; | |
170 | ||
171 | if (!dentry) | |
2743c515 | 172 | return ERR_PTR(-ENOENT); |
16d13b59 | 173 | |
2b0143b5 | 174 | if (d_really_is_positive(dentry)) |
2743c515 | 175 | return ERR_PTR(-EEXIST); |
7063fbf2 | 176 | |
16d13b59 AV |
177 | sd = dentry->d_fsdata; |
178 | inode = configfs_new_inode(mode, sd, dentry->d_sb); | |
179 | if (!inode) | |
2743c515 | 180 | return ERR_PTR(-ENOMEM); |
16d13b59 | 181 | |
2b0143b5 | 182 | p_inode = d_inode(dentry->d_parent); |
c2050a45 | 183 | p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode); |
16d13b59 | 184 | configfs_set_inode_lock_class(sd, inode); |
2743c515 | 185 | return inode; |
7063fbf2 JB |
186 | } |
187 | ||
188 | /* | |
189 | * Get the name for corresponding element represented by the given configfs_dirent | |
190 | */ | |
191 | const unsigned char * configfs_get_name(struct configfs_dirent *sd) | |
192 | { | |
3d0f89bb | 193 | struct configfs_attribute *attr; |
7063fbf2 | 194 | |
1a1974fd | 195 | BUG_ON(!sd || !sd->s_element); |
7063fbf2 JB |
196 | |
197 | /* These always have a dentry, so use that */ | |
198 | if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) | |
199 | return sd->s_dentry->d_name.name; | |
200 | ||
03607ace | 201 | if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) { |
7063fbf2 | 202 | attr = sd->s_element; |
3d0f89bb | 203 | return attr->ca_name; |
7063fbf2 JB |
204 | } |
205 | return NULL; | |
206 | } | |
207 | ||
208 | ||
209 | /* | |
210 | * Unhashes the dentry corresponding to given configfs_dirent | |
1b1dcc1b | 211 | * Called with parent inode's i_mutex held. |
7063fbf2 JB |
212 | */ |
213 | void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) | |
214 | { | |
215 | struct dentry * dentry = sd->s_dentry; | |
216 | ||
217 | if (dentry) { | |
3d0f89bb | 218 | spin_lock(&dentry->d_lock); |
dc3f4198 | 219 | if (simple_positive(dentry)) { |
dc0474be | 220 | dget_dlock(dentry); |
7063fbf2 | 221 | __d_drop(dentry); |
3d0f89bb | 222 | spin_unlock(&dentry->d_lock); |
2b0143b5 | 223 | simple_unlink(d_inode(parent), dentry); |
b5c84bf6 | 224 | } else |
3d0f89bb | 225 | spin_unlock(&dentry->d_lock); |
7063fbf2 JB |
226 | } |
227 | } | |
228 | ||
229 | void configfs_hash_and_remove(struct dentry * dir, const char * name) | |
230 | { | |
231 | struct configfs_dirent * sd; | |
232 | struct configfs_dirent * parent_sd = dir->d_fsdata; | |
233 | ||
2b0143b5 | 234 | if (d_really_is_negative(dir)) |
3d0f89bb JB |
235 | /* no inode means this hasn't been made visible yet */ |
236 | return; | |
237 | ||
5955102c | 238 | inode_lock(d_inode(dir)); |
7063fbf2 JB |
239 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
240 | if (!sd->s_element) | |
241 | continue; | |
242 | if (!strcmp(configfs_get_name(sd), name)) { | |
6f610764 | 243 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 244 | list_del_init(&sd->s_sibling); |
6f610764 | 245 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
246 | configfs_drop_dentry(sd, dir); |
247 | configfs_put(sd); | |
248 | break; | |
249 | } | |
250 | } | |
5955102c | 251 | inode_unlock(d_inode(dir)); |
7063fbf2 | 252 | } |