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1/*
2 * fs/kernfs/inode.c - kernfs inode implementation
3 *
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
7 *
8 * This file is released under the GPLv2.
9 */
10
11#include <linux/pagemap.h>
12#include <linux/backing-dev.h>
13#include <linux/capability.h>
14#include <linux/errno.h>
15#include <linux/slab.h>
16#include <linux/xattr.h>
17#include <linux/security.h>
18
19#include "kernfs-internal.h"
20
21static const struct address_space_operations kernfs_aops = {
22 .readpage = simple_readpage,
23 .write_begin = simple_write_begin,
24 .write_end = simple_write_end,
25};
26
27static const struct inode_operations kernfs_iops = {
28 .permission = kernfs_iop_permission,
29 .setattr = kernfs_iop_setattr,
30 .getattr = kernfs_iop_getattr,
31 .listxattr = kernfs_iop_listxattr,
32};
33
34static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
35{
36 static DEFINE_MUTEX(iattr_mutex);
37 struct kernfs_iattrs *ret;
38 struct iattr *iattrs;
39
40 mutex_lock(&iattr_mutex);
41
42 if (kn->iattr)
43 goto out_unlock;
44
45 kn->iattr = kzalloc(sizeof(struct kernfs_iattrs), GFP_KERNEL);
46 if (!kn->iattr)
47 goto out_unlock;
48 iattrs = &kn->iattr->ia_iattr;
49
50 /* assign default attributes */
51 iattrs->ia_mode = kn->mode;
52 iattrs->ia_uid = GLOBAL_ROOT_UID;
53 iattrs->ia_gid = GLOBAL_ROOT_GID;
54
55 ktime_get_real_ts(&iattrs->ia_atime);
56 iattrs->ia_mtime = iattrs->ia_atime;
57 iattrs->ia_ctime = iattrs->ia_atime;
58
59 simple_xattrs_init(&kn->iattr->xattrs);
60out_unlock:
61 ret = kn->iattr;
62 mutex_unlock(&iattr_mutex);
63 return ret;
64}
65
66static int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
67{
68 struct kernfs_iattrs *attrs;
69 struct iattr *iattrs;
70 unsigned int ia_valid = iattr->ia_valid;
71
72 attrs = kernfs_iattrs(kn);
73 if (!attrs)
74 return -ENOMEM;
75
76 iattrs = &attrs->ia_iattr;
77
78 if (ia_valid & ATTR_UID)
79 iattrs->ia_uid = iattr->ia_uid;
80 if (ia_valid & ATTR_GID)
81 iattrs->ia_gid = iattr->ia_gid;
82 if (ia_valid & ATTR_ATIME)
83 iattrs->ia_atime = iattr->ia_atime;
84 if (ia_valid & ATTR_MTIME)
85 iattrs->ia_mtime = iattr->ia_mtime;
86 if (ia_valid & ATTR_CTIME)
87 iattrs->ia_ctime = iattr->ia_ctime;
88 if (ia_valid & ATTR_MODE) {
89 umode_t mode = iattr->ia_mode;
90 iattrs->ia_mode = kn->mode = mode;
91 }
92 return 0;
93}
94
95/**
96 * kernfs_setattr - set iattr on a node
97 * @kn: target node
98 * @iattr: iattr to set
99 *
100 * Returns 0 on success, -errno on failure.
101 */
102int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
103{
104 int ret;
105
106 mutex_lock(&kernfs_mutex);
107 ret = __kernfs_setattr(kn, iattr);
108 mutex_unlock(&kernfs_mutex);
109 return ret;
110}
111
112int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr)
113{
114 struct inode *inode = d_inode(dentry);
115 struct kernfs_node *kn = dentry->d_fsdata;
116 int error;
117
118 if (!kn)
119 return -EINVAL;
120
121 mutex_lock(&kernfs_mutex);
122 error = setattr_prepare(dentry, iattr);
123 if (error)
124 goto out;
125
126 error = __kernfs_setattr(kn, iattr);
127 if (error)
128 goto out;
129
130 /* this ignores size changes */
131 setattr_copy(inode, iattr);
132
133out:
134 mutex_unlock(&kernfs_mutex);
135 return error;
136}
137
138static int kernfs_node_setsecdata(struct kernfs_iattrs *attrs, void **secdata,
139 u32 *secdata_len)
140{
141 void *old_secdata;
142 size_t old_secdata_len;
143
144 old_secdata = attrs->ia_secdata;
145 old_secdata_len = attrs->ia_secdata_len;
146
147 attrs->ia_secdata = *secdata;
148 attrs->ia_secdata_len = *secdata_len;
149
150 *secdata = old_secdata;
151 *secdata_len = old_secdata_len;
152 return 0;
153}
154
155ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
156{
157 struct kernfs_node *kn = dentry->d_fsdata;
158 struct kernfs_iattrs *attrs;
159
160 attrs = kernfs_iattrs(kn);
161 if (!attrs)
162 return -ENOMEM;
163
164 return simple_xattr_list(d_inode(dentry), &attrs->xattrs, buf, size);
165}
166
167static inline void set_default_inode_attr(struct inode *inode, umode_t mode)
168{
169 inode->i_mode = mode;
170 inode->i_atime = inode->i_mtime =
171 inode->i_ctime = current_time(inode);
172}
173
174static inline void set_inode_attr(struct inode *inode, struct iattr *iattr)
175{
176 struct super_block *sb = inode->i_sb;
177 inode->i_uid = iattr->ia_uid;
178 inode->i_gid = iattr->ia_gid;
179 inode->i_atime = timespec_trunc(iattr->ia_atime, sb->s_time_gran);
180 inode->i_mtime = timespec_trunc(iattr->ia_mtime, sb->s_time_gran);
181 inode->i_ctime = timespec_trunc(iattr->ia_ctime, sb->s_time_gran);
182}
183
184static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
185{
186 struct kernfs_iattrs *attrs = kn->iattr;
187
188 inode->i_mode = kn->mode;
189 if (attrs) {
190 /*
191 * kernfs_node has non-default attributes get them from
192 * persistent copy in kernfs_node.
193 */
194 set_inode_attr(inode, &attrs->ia_iattr);
195 security_inode_notifysecctx(inode, attrs->ia_secdata,
196 attrs->ia_secdata_len);
197 }
198
199 if (kernfs_type(kn) == KERNFS_DIR)
200 set_nlink(inode, kn->dir.subdirs + 2);
201}
202
203int kernfs_iop_getattr(struct vfsmount *mnt, struct dentry *dentry,
204 struct kstat *stat)
205{
206 struct kernfs_node *kn = dentry->d_fsdata;
207 struct inode *inode = d_inode(dentry);
208
209 mutex_lock(&kernfs_mutex);
210 kernfs_refresh_inode(kn, inode);
211 mutex_unlock(&kernfs_mutex);
212
213 generic_fillattr(inode, stat);
214 return 0;
215}
216
217static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode)
218{
219 kernfs_get(kn);
220 inode->i_private = kn;
221 inode->i_mapping->a_ops = &kernfs_aops;
222 inode->i_op = &kernfs_iops;
223
224 set_default_inode_attr(inode, kn->mode);
225 kernfs_refresh_inode(kn, inode);
226
227 /* initialize inode according to type */
228 switch (kernfs_type(kn)) {
229 case KERNFS_DIR:
230 inode->i_op = &kernfs_dir_iops;
231 inode->i_fop = &kernfs_dir_fops;
232 if (kn->flags & KERNFS_EMPTY_DIR)
233 make_empty_dir_inode(inode);
234 break;
235 case KERNFS_FILE:
236 inode->i_size = kn->attr.size;
237 inode->i_fop = &kernfs_file_fops;
238 break;
239 case KERNFS_LINK:
240 inode->i_op = &kernfs_symlink_iops;
241 break;
242 default:
243 BUG();
244 }
245
246 unlock_new_inode(inode);
247}
248
249/**
250 * kernfs_get_inode - get inode for kernfs_node
251 * @sb: super block
252 * @kn: kernfs_node to allocate inode for
253 *
254 * Get inode for @kn. If such inode doesn't exist, a new inode is
255 * allocated and basics are initialized. New inode is returned
256 * locked.
257 *
258 * LOCKING:
259 * Kernel thread context (may sleep).
260 *
261 * RETURNS:
262 * Pointer to allocated inode on success, NULL on failure.
263 */
264struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
265{
266 struct inode *inode;
267
268 inode = iget_locked(sb, kn->ino);
269 if (inode && (inode->i_state & I_NEW))
270 kernfs_init_inode(kn, inode);
271
272 return inode;
273}
274
275/*
276 * The kernfs_node serves as both an inode and a directory entry for
277 * kernfs. To prevent the kernfs inode numbers from being freed
278 * prematurely we take a reference to kernfs_node from the kernfs inode. A
279 * super_operations.evict_inode() implementation is needed to drop that
280 * reference upon inode destruction.
281 */
282void kernfs_evict_inode(struct inode *inode)
283{
284 struct kernfs_node *kn = inode->i_private;
285
286 truncate_inode_pages_final(&inode->i_data);
287 clear_inode(inode);
288 kernfs_put(kn);
289}
290
291int kernfs_iop_permission(struct inode *inode, int mask)
292{
293 struct kernfs_node *kn;
294
295 if (mask & MAY_NOT_BLOCK)
296 return -ECHILD;
297
298 kn = inode->i_private;
299
300 mutex_lock(&kernfs_mutex);
301 kernfs_refresh_inode(kn, inode);
302 mutex_unlock(&kernfs_mutex);
303
304 return generic_permission(inode, mask);
305}
306
307static int kernfs_xattr_get(const struct xattr_handler *handler,
308 struct dentry *unused, struct inode *inode,
309 const char *suffix, void *value, size_t size)
310{
311 const char *name = xattr_full_name(handler, suffix);
312 struct kernfs_node *kn = inode->i_private;
313 struct kernfs_iattrs *attrs;
314
315 attrs = kernfs_iattrs(kn);
316 if (!attrs)
317 return -ENOMEM;
318
319 return simple_xattr_get(&attrs->xattrs, name, value, size);
320}
321
322static int kernfs_xattr_set(const struct xattr_handler *handler,
323 struct dentry *unused, struct inode *inode,
324 const char *suffix, const void *value,
325 size_t size, int flags)
326{
327 const char *name = xattr_full_name(handler, suffix);
328 struct kernfs_node *kn = inode->i_private;
329 struct kernfs_iattrs *attrs;
330
331 attrs = kernfs_iattrs(kn);
332 if (!attrs)
333 return -ENOMEM;
334
335 return simple_xattr_set(&attrs->xattrs, name, value, size, flags);
336}
337
338static const struct xattr_handler kernfs_trusted_xattr_handler = {
339 .prefix = XATTR_TRUSTED_PREFIX,
340 .get = kernfs_xattr_get,
341 .set = kernfs_xattr_set,
342};
343
344static int kernfs_security_xattr_set(const struct xattr_handler *handler,
345 struct dentry *unused, struct inode *inode,
346 const char *suffix, const void *value,
347 size_t size, int flags)
348{
349 struct kernfs_node *kn = inode->i_private;
350 struct kernfs_iattrs *attrs;
351 void *secdata;
352 u32 secdata_len = 0;
353 int error;
354
355 attrs = kernfs_iattrs(kn);
356 if (!attrs)
357 return -ENOMEM;
358
359 error = security_inode_setsecurity(inode, suffix, value, size, flags);
360 if (error)
361 return error;
362 error = security_inode_getsecctx(inode, &secdata, &secdata_len);
363 if (error)
364 return error;
365
366 mutex_lock(&kernfs_mutex);
367 error = kernfs_node_setsecdata(attrs, &secdata, &secdata_len);
368 mutex_unlock(&kernfs_mutex);
369
370 if (secdata)
371 security_release_secctx(secdata, secdata_len);
372 return error;
373}
374
375static const struct xattr_handler kernfs_security_xattr_handler = {
376 .prefix = XATTR_SECURITY_PREFIX,
377 .get = kernfs_xattr_get,
378 .set = kernfs_security_xattr_set,
379};
380
381const struct xattr_handler *kernfs_xattr_handlers[] = {
382 &kernfs_trusted_xattr_handler,
383 &kernfs_security_xattr_handler,
384 NULL
385};
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * fs/kernfs/inode.c - kernfs inode implementation
4 *
5 * Copyright (c) 2001-3 Patrick Mochel
6 * Copyright (c) 2007 SUSE Linux Products GmbH
7 * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
8 */
9
10#include <linux/pagemap.h>
11#include <linux/backing-dev.h>
12#include <linux/capability.h>
13#include <linux/errno.h>
14#include <linux/slab.h>
15#include <linux/xattr.h>
16#include <linux/security.h>
17
18#include "kernfs-internal.h"
19
20static const struct address_space_operations kernfs_aops = {
21 .readpage = simple_readpage,
22 .write_begin = simple_write_begin,
23 .write_end = simple_write_end,
24};
25
26static const struct inode_operations kernfs_iops = {
27 .permission = kernfs_iop_permission,
28 .setattr = kernfs_iop_setattr,
29 .getattr = kernfs_iop_getattr,
30 .listxattr = kernfs_iop_listxattr,
31};
32
33static struct kernfs_iattrs *__kernfs_iattrs(struct kernfs_node *kn, int alloc)
34{
35 static DEFINE_MUTEX(iattr_mutex);
36 struct kernfs_iattrs *ret;
37
38 mutex_lock(&iattr_mutex);
39
40 if (kn->iattr || !alloc)
41 goto out_unlock;
42
43 kn->iattr = kmem_cache_zalloc(kernfs_iattrs_cache, GFP_KERNEL);
44 if (!kn->iattr)
45 goto out_unlock;
46
47 /* assign default attributes */
48 kn->iattr->ia_uid = GLOBAL_ROOT_UID;
49 kn->iattr->ia_gid = GLOBAL_ROOT_GID;
50
51 ktime_get_real_ts64(&kn->iattr->ia_atime);
52 kn->iattr->ia_mtime = kn->iattr->ia_atime;
53 kn->iattr->ia_ctime = kn->iattr->ia_atime;
54
55 simple_xattrs_init(&kn->iattr->xattrs);
56 atomic_set(&kn->iattr->nr_user_xattrs, 0);
57 atomic_set(&kn->iattr->user_xattr_size, 0);
58out_unlock:
59 ret = kn->iattr;
60 mutex_unlock(&iattr_mutex);
61 return ret;
62}
63
64static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
65{
66 return __kernfs_iattrs(kn, 1);
67}
68
69static struct kernfs_iattrs *kernfs_iattrs_noalloc(struct kernfs_node *kn)
70{
71 return __kernfs_iattrs(kn, 0);
72}
73
74int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
75{
76 struct kernfs_iattrs *attrs;
77 unsigned int ia_valid = iattr->ia_valid;
78
79 attrs = kernfs_iattrs(kn);
80 if (!attrs)
81 return -ENOMEM;
82
83 if (ia_valid & ATTR_UID)
84 attrs->ia_uid = iattr->ia_uid;
85 if (ia_valid & ATTR_GID)
86 attrs->ia_gid = iattr->ia_gid;
87 if (ia_valid & ATTR_ATIME)
88 attrs->ia_atime = iattr->ia_atime;
89 if (ia_valid & ATTR_MTIME)
90 attrs->ia_mtime = iattr->ia_mtime;
91 if (ia_valid & ATTR_CTIME)
92 attrs->ia_ctime = iattr->ia_ctime;
93 if (ia_valid & ATTR_MODE)
94 kn->mode = iattr->ia_mode;
95 return 0;
96}
97
98/**
99 * kernfs_setattr - set iattr on a node
100 * @kn: target node
101 * @iattr: iattr to set
102 *
103 * Returns 0 on success, -errno on failure.
104 */
105int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
106{
107 int ret;
108
109 mutex_lock(&kernfs_mutex);
110 ret = __kernfs_setattr(kn, iattr);
111 mutex_unlock(&kernfs_mutex);
112 return ret;
113}
114
115int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr)
116{
117 struct inode *inode = d_inode(dentry);
118 struct kernfs_node *kn = inode->i_private;
119 int error;
120
121 if (!kn)
122 return -EINVAL;
123
124 mutex_lock(&kernfs_mutex);
125 error = setattr_prepare(dentry, iattr);
126 if (error)
127 goto out;
128
129 error = __kernfs_setattr(kn, iattr);
130 if (error)
131 goto out;
132
133 /* this ignores size changes */
134 setattr_copy(inode, iattr);
135
136out:
137 mutex_unlock(&kernfs_mutex);
138 return error;
139}
140
141ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
142{
143 struct kernfs_node *kn = kernfs_dentry_node(dentry);
144 struct kernfs_iattrs *attrs;
145
146 attrs = kernfs_iattrs(kn);
147 if (!attrs)
148 return -ENOMEM;
149
150 return simple_xattr_list(d_inode(dentry), &attrs->xattrs, buf, size);
151}
152
153static inline void set_default_inode_attr(struct inode *inode, umode_t mode)
154{
155 inode->i_mode = mode;
156 inode->i_atime = inode->i_mtime =
157 inode->i_ctime = current_time(inode);
158}
159
160static inline void set_inode_attr(struct inode *inode,
161 struct kernfs_iattrs *attrs)
162{
163 inode->i_uid = attrs->ia_uid;
164 inode->i_gid = attrs->ia_gid;
165 inode->i_atime = attrs->ia_atime;
166 inode->i_mtime = attrs->ia_mtime;
167 inode->i_ctime = attrs->ia_ctime;
168}
169
170static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
171{
172 struct kernfs_iattrs *attrs = kn->iattr;
173
174 inode->i_mode = kn->mode;
175 if (attrs)
176 /*
177 * kernfs_node has non-default attributes get them from
178 * persistent copy in kernfs_node.
179 */
180 set_inode_attr(inode, attrs);
181
182 if (kernfs_type(kn) == KERNFS_DIR)
183 set_nlink(inode, kn->dir.subdirs + 2);
184}
185
186int kernfs_iop_getattr(const struct path *path, struct kstat *stat,
187 u32 request_mask, unsigned int query_flags)
188{
189 struct inode *inode = d_inode(path->dentry);
190 struct kernfs_node *kn = inode->i_private;
191
192 mutex_lock(&kernfs_mutex);
193 kernfs_refresh_inode(kn, inode);
194 mutex_unlock(&kernfs_mutex);
195
196 generic_fillattr(inode, stat);
197 return 0;
198}
199
200static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode)
201{
202 kernfs_get(kn);
203 inode->i_private = kn;
204 inode->i_mapping->a_ops = &kernfs_aops;
205 inode->i_op = &kernfs_iops;
206 inode->i_generation = kernfs_gen(kn);
207
208 set_default_inode_attr(inode, kn->mode);
209 kernfs_refresh_inode(kn, inode);
210
211 /* initialize inode according to type */
212 switch (kernfs_type(kn)) {
213 case KERNFS_DIR:
214 inode->i_op = &kernfs_dir_iops;
215 inode->i_fop = &kernfs_dir_fops;
216 if (kn->flags & KERNFS_EMPTY_DIR)
217 make_empty_dir_inode(inode);
218 break;
219 case KERNFS_FILE:
220 inode->i_size = kn->attr.size;
221 inode->i_fop = &kernfs_file_fops;
222 break;
223 case KERNFS_LINK:
224 inode->i_op = &kernfs_symlink_iops;
225 break;
226 default:
227 BUG();
228 }
229
230 unlock_new_inode(inode);
231}
232
233/**
234 * kernfs_get_inode - get inode for kernfs_node
235 * @sb: super block
236 * @kn: kernfs_node to allocate inode for
237 *
238 * Get inode for @kn. If such inode doesn't exist, a new inode is
239 * allocated and basics are initialized. New inode is returned
240 * locked.
241 *
242 * LOCKING:
243 * Kernel thread context (may sleep).
244 *
245 * RETURNS:
246 * Pointer to allocated inode on success, NULL on failure.
247 */
248struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
249{
250 struct inode *inode;
251
252 inode = iget_locked(sb, kernfs_ino(kn));
253 if (inode && (inode->i_state & I_NEW))
254 kernfs_init_inode(kn, inode);
255
256 return inode;
257}
258
259/*
260 * The kernfs_node serves as both an inode and a directory entry for
261 * kernfs. To prevent the kernfs inode numbers from being freed
262 * prematurely we take a reference to kernfs_node from the kernfs inode. A
263 * super_operations.evict_inode() implementation is needed to drop that
264 * reference upon inode destruction.
265 */
266void kernfs_evict_inode(struct inode *inode)
267{
268 struct kernfs_node *kn = inode->i_private;
269
270 truncate_inode_pages_final(&inode->i_data);
271 clear_inode(inode);
272 kernfs_put(kn);
273}
274
275int kernfs_iop_permission(struct inode *inode, int mask)
276{
277 struct kernfs_node *kn;
278
279 if (mask & MAY_NOT_BLOCK)
280 return -ECHILD;
281
282 kn = inode->i_private;
283
284 mutex_lock(&kernfs_mutex);
285 kernfs_refresh_inode(kn, inode);
286 mutex_unlock(&kernfs_mutex);
287
288 return generic_permission(inode, mask);
289}
290
291int kernfs_xattr_get(struct kernfs_node *kn, const char *name,
292 void *value, size_t size)
293{
294 struct kernfs_iattrs *attrs = kernfs_iattrs_noalloc(kn);
295 if (!attrs)
296 return -ENODATA;
297
298 return simple_xattr_get(&attrs->xattrs, name, value, size);
299}
300
301int kernfs_xattr_set(struct kernfs_node *kn, const char *name,
302 const void *value, size_t size, int flags)
303{
304 struct kernfs_iattrs *attrs = kernfs_iattrs(kn);
305 if (!attrs)
306 return -ENOMEM;
307
308 return simple_xattr_set(&attrs->xattrs, name, value, size, flags, NULL);
309}
310
311static int kernfs_vfs_xattr_get(const struct xattr_handler *handler,
312 struct dentry *unused, struct inode *inode,
313 const char *suffix, void *value, size_t size)
314{
315 const char *name = xattr_full_name(handler, suffix);
316 struct kernfs_node *kn = inode->i_private;
317
318 return kernfs_xattr_get(kn, name, value, size);
319}
320
321static int kernfs_vfs_xattr_set(const struct xattr_handler *handler,
322 struct dentry *unused, struct inode *inode,
323 const char *suffix, const void *value,
324 size_t size, int flags)
325{
326 const char *name = xattr_full_name(handler, suffix);
327 struct kernfs_node *kn = inode->i_private;
328
329 return kernfs_xattr_set(kn, name, value, size, flags);
330}
331
332static int kernfs_vfs_user_xattr_add(struct kernfs_node *kn,
333 const char *full_name,
334 struct simple_xattrs *xattrs,
335 const void *value, size_t size, int flags)
336{
337 atomic_t *sz = &kn->iattr->user_xattr_size;
338 atomic_t *nr = &kn->iattr->nr_user_xattrs;
339 ssize_t removed_size;
340 int ret;
341
342 if (atomic_inc_return(nr) > KERNFS_MAX_USER_XATTRS) {
343 ret = -ENOSPC;
344 goto dec_count_out;
345 }
346
347 if (atomic_add_return(size, sz) > KERNFS_USER_XATTR_SIZE_LIMIT) {
348 ret = -ENOSPC;
349 goto dec_size_out;
350 }
351
352 ret = simple_xattr_set(xattrs, full_name, value, size, flags,
353 &removed_size);
354
355 if (!ret && removed_size >= 0)
356 size = removed_size;
357 else if (!ret)
358 return 0;
359dec_size_out:
360 atomic_sub(size, sz);
361dec_count_out:
362 atomic_dec(nr);
363 return ret;
364}
365
366static int kernfs_vfs_user_xattr_rm(struct kernfs_node *kn,
367 const char *full_name,
368 struct simple_xattrs *xattrs,
369 const void *value, size_t size, int flags)
370{
371 atomic_t *sz = &kn->iattr->user_xattr_size;
372 atomic_t *nr = &kn->iattr->nr_user_xattrs;
373 ssize_t removed_size;
374 int ret;
375
376 ret = simple_xattr_set(xattrs, full_name, value, size, flags,
377 &removed_size);
378
379 if (removed_size >= 0) {
380 atomic_sub(removed_size, sz);
381 atomic_dec(nr);
382 }
383
384 return ret;
385}
386
387static int kernfs_vfs_user_xattr_set(const struct xattr_handler *handler,
388 struct dentry *unused, struct inode *inode,
389 const char *suffix, const void *value,
390 size_t size, int flags)
391{
392 const char *full_name = xattr_full_name(handler, suffix);
393 struct kernfs_node *kn = inode->i_private;
394 struct kernfs_iattrs *attrs;
395
396 if (!(kernfs_root(kn)->flags & KERNFS_ROOT_SUPPORT_USER_XATTR))
397 return -EOPNOTSUPP;
398
399 attrs = kernfs_iattrs(kn);
400 if (!attrs)
401 return -ENOMEM;
402
403 if (value)
404 return kernfs_vfs_user_xattr_add(kn, full_name, &attrs->xattrs,
405 value, size, flags);
406 else
407 return kernfs_vfs_user_xattr_rm(kn, full_name, &attrs->xattrs,
408 value, size, flags);
409
410}
411
412static const struct xattr_handler kernfs_trusted_xattr_handler = {
413 .prefix = XATTR_TRUSTED_PREFIX,
414 .get = kernfs_vfs_xattr_get,
415 .set = kernfs_vfs_xattr_set,
416};
417
418static const struct xattr_handler kernfs_security_xattr_handler = {
419 .prefix = XATTR_SECURITY_PREFIX,
420 .get = kernfs_vfs_xattr_get,
421 .set = kernfs_vfs_xattr_set,
422};
423
424static const struct xattr_handler kernfs_user_xattr_handler = {
425 .prefix = XATTR_USER_PREFIX,
426 .get = kernfs_vfs_xattr_get,
427 .set = kernfs_vfs_user_xattr_set,
428};
429
430const struct xattr_handler *kernfs_xattr_handlers[] = {
431 &kernfs_trusted_xattr_handler,
432 &kernfs_security_xattr_handler,
433 &kernfs_user_xattr_handler,
434 NULL
435};