blob: a8a68745e11d45b0c093501e359d1190546f788b [file] [log] [blame]
David Howells9ae326a2009-04-03 16:42:41 +01001/* CacheFiles extended attribute management
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <linux/sched.h>
14#include <linux/file.h>
15#include <linux/fs.h>
16#include <linux/fsnotify.h>
17#include <linux/quotaops.h>
18#include <linux/xattr.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090019#include <linux/slab.h>
David Howells9ae326a2009-04-03 16:42:41 +010020#include "internal.h"
21
22static const char cachefiles_xattr_cache[] =
23 XATTR_USER_PREFIX "CacheFiles.cache";
24
25/*
26 * check the type label on an object
27 * - done using xattrs
28 */
29int cachefiles_check_object_type(struct cachefiles_object *object)
30{
31 struct dentry *dentry = object->dentry;
32 char type[3], xtype[3];
33 int ret;
34
35 ASSERT(dentry);
36 ASSERT(dentry->d_inode);
37
38 if (!object->fscache.cookie)
39 strcpy(type, "C3");
40 else
41 snprintf(type, 3, "%02x", object->fscache.cookie->def->type);
42
43 _enter("%p{%s}", object, type);
44
45 /* attempt to install a type label directly */
46 ret = vfs_setxattr(dentry, cachefiles_xattr_cache, type, 2,
47 XATTR_CREATE);
48 if (ret == 0) {
49 _debug("SET"); /* we succeeded */
50 goto error;
51 }
52
53 if (ret != -EEXIST) {
Al Viroa4555892014-10-21 20:11:25 -040054 pr_err("Can't set xattr on %pd [%lu] (err %d)\n",
55 dentry, dentry->d_inode->i_ino,
David Howells9ae326a2009-04-03 16:42:41 +010056 -ret);
57 goto error;
58 }
59
60 /* read the current type label */
61 ret = vfs_getxattr(dentry, cachefiles_xattr_cache, xtype, 3);
62 if (ret < 0) {
63 if (ret == -ERANGE)
64 goto bad_type_length;
65
Al Viroa4555892014-10-21 20:11:25 -040066 pr_err("Can't read xattr on %pd [%lu] (err %d)\n",
67 dentry, dentry->d_inode->i_ino,
David Howells9ae326a2009-04-03 16:42:41 +010068 -ret);
69 goto error;
70 }
71
72 /* check the type is what we're expecting */
73 if (ret != 2)
74 goto bad_type_length;
75
76 if (xtype[0] != type[0] || xtype[1] != type[1])
77 goto bad_type;
78
79 ret = 0;
80
81error:
82 _leave(" = %d", ret);
83 return ret;
84
85bad_type_length:
Fabian Frederick6ff66ac2014-09-25 16:05:27 -070086 pr_err("Cache object %lu type xattr length incorrect\n",
David Howells9ae326a2009-04-03 16:42:41 +010087 dentry->d_inode->i_ino);
88 ret = -EIO;
89 goto error;
90
91bad_type:
92 xtype[2] = 0;
Al Viroa4555892014-10-21 20:11:25 -040093 pr_err("Cache object %pd [%lu] type %s not %s\n",
94 dentry, dentry->d_inode->i_ino,
David Howells9ae326a2009-04-03 16:42:41 +010095 xtype, type);
96 ret = -EIO;
97 goto error;
98}
99
100/*
101 * set the state xattr on a cache file
102 */
103int cachefiles_set_object_xattr(struct cachefiles_object *object,
104 struct cachefiles_xattr *auxdata)
105{
106 struct dentry *dentry = object->dentry;
107 int ret;
108
David Howells9ae326a2009-04-03 16:42:41 +0100109 ASSERT(dentry);
110
111 _enter("%p,#%d", object, auxdata->len);
112
113 /* attempt to install the cache metadata directly */
David Howells13627292013-05-10 19:50:26 +0100114 _debug("SET #%u", auxdata->len);
David Howells9ae326a2009-04-03 16:42:41 +0100115
116 ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
117 &auxdata->type, auxdata->len,
118 XATTR_CREATE);
119 if (ret < 0 && ret != -ENOMEM)
120 cachefiles_io_error_obj(
121 object,
122 "Failed to set xattr with error %d", ret);
123
124 _leave(" = %d", ret);
125 return ret;
126}
127
128/*
129 * update the state xattr on a cache file
130 */
131int cachefiles_update_object_xattr(struct cachefiles_object *object,
132 struct cachefiles_xattr *auxdata)
133{
134 struct dentry *dentry = object->dentry;
135 int ret;
136
David Howells9ae326a2009-04-03 16:42:41 +0100137 ASSERT(dentry);
138
139 _enter("%p,#%d", object, auxdata->len);
140
141 /* attempt to install the cache metadata directly */
David Howells13627292013-05-10 19:50:26 +0100142 _debug("SET #%u", auxdata->len);
David Howells9ae326a2009-04-03 16:42:41 +0100143
144 ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
145 &auxdata->type, auxdata->len,
146 XATTR_REPLACE);
147 if (ret < 0 && ret != -ENOMEM)
148 cachefiles_io_error_obj(
149 object,
150 "Failed to update xattr with error %d", ret);
151
152 _leave(" = %d", ret);
153 return ret;
154}
155
156/*
David Howells5002d7b2013-08-21 17:29:21 -0400157 * check the consistency between the backing cache and the FS-Cache cookie
158 */
159int cachefiles_check_auxdata(struct cachefiles_object *object)
160{
161 struct cachefiles_xattr *auxbuf;
Josh Boyer607566a2013-09-20 14:17:52 +0100162 enum fscache_checkaux validity;
David Howells5002d7b2013-08-21 17:29:21 -0400163 struct dentry *dentry = object->dentry;
Josh Boyer607566a2013-09-20 14:17:52 +0100164 ssize_t xlen;
David Howells5002d7b2013-08-21 17:29:21 -0400165 int ret;
166
167 ASSERT(dentry);
168 ASSERT(dentry->d_inode);
169 ASSERT(object->fscache.cookie->def->check_aux);
170
171 auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL);
172 if (!auxbuf)
173 return -ENOMEM;
174
Josh Boyer607566a2013-09-20 14:17:52 +0100175 xlen = vfs_getxattr(dentry, cachefiles_xattr_cache,
176 &auxbuf->type, 512 + 1);
177 ret = -ESTALE;
178 if (xlen < 1 ||
179 auxbuf->type != object->fscache.cookie->def->type)
180 goto error;
David Howells5002d7b2013-08-21 17:29:21 -0400181
Josh Boyer607566a2013-09-20 14:17:52 +0100182 xlen--;
183 validity = fscache_check_aux(&object->fscache, &auxbuf->data, xlen);
184 if (validity != FSCACHE_CHECKAUX_OKAY)
185 goto error;
David Howells5002d7b2013-08-21 17:29:21 -0400186
Josh Boyer607566a2013-09-20 14:17:52 +0100187 ret = 0;
188error:
David Howells5002d7b2013-08-21 17:29:21 -0400189 kfree(auxbuf);
Josh Boyer607566a2013-09-20 14:17:52 +0100190 return ret;
David Howells5002d7b2013-08-21 17:29:21 -0400191}
192
193/*
David Howells9ae326a2009-04-03 16:42:41 +0100194 * check the state xattr on a cache file
195 * - return -ESTALE if the object should be deleted
196 */
197int cachefiles_check_object_xattr(struct cachefiles_object *object,
198 struct cachefiles_xattr *auxdata)
199{
200 struct cachefiles_xattr *auxbuf;
201 struct dentry *dentry = object->dentry;
202 int ret;
203
204 _enter("%p,#%d", object, auxdata->len);
205
206 ASSERT(dentry);
207 ASSERT(dentry->d_inode);
208
David Howells5f4f9f42012-12-20 21:52:33 +0000209 auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, cachefiles_gfp);
David Howells9ae326a2009-04-03 16:42:41 +0100210 if (!auxbuf) {
211 _leave(" = -ENOMEM");
212 return -ENOMEM;
213 }
214
215 /* read the current type label */
216 ret = vfs_getxattr(dentry, cachefiles_xattr_cache,
217 &auxbuf->type, 512 + 1);
218 if (ret < 0) {
219 if (ret == -ENODATA)
220 goto stale; /* no attribute - power went off
221 * mid-cull? */
222
223 if (ret == -ERANGE)
224 goto bad_type_length;
225
226 cachefiles_io_error_obj(object,
227 "Can't read xattr on %lu (err %d)",
228 dentry->d_inode->i_ino, -ret);
229 goto error;
230 }
231
232 /* check the on-disk object */
233 if (ret < 1)
234 goto bad_type_length;
235
236 if (auxbuf->type != auxdata->type)
237 goto stale;
238
239 auxbuf->len = ret;
240
241 /* consult the netfs */
242 if (object->fscache.cookie->def->check_aux) {
243 enum fscache_checkaux result;
244 unsigned int dlen;
245
246 dlen = auxbuf->len - 1;
247
248 _debug("checkaux %s #%u",
249 object->fscache.cookie->def->name, dlen);
250
251 result = fscache_check_aux(&object->fscache,
252 &auxbuf->data, dlen);
253
254 switch (result) {
255 /* entry okay as is */
256 case FSCACHE_CHECKAUX_OKAY:
257 goto okay;
258
259 /* entry requires update */
260 case FSCACHE_CHECKAUX_NEEDS_UPDATE:
261 break;
262
263 /* entry requires deletion */
264 case FSCACHE_CHECKAUX_OBSOLETE:
265 goto stale;
266
267 default:
268 BUG();
269 }
270
271 /* update the current label */
272 ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
273 &auxdata->type, auxdata->len,
274 XATTR_REPLACE);
275 if (ret < 0) {
276 cachefiles_io_error_obj(object,
277 "Can't update xattr on %lu"
278 " (error %d)",
279 dentry->d_inode->i_ino, -ret);
280 goto error;
281 }
282 }
283
284okay:
285 ret = 0;
286
287error:
288 kfree(auxbuf);
289 _leave(" = %d", ret);
290 return ret;
291
292bad_type_length:
Fabian Frederick6ff66ac2014-09-25 16:05:27 -0700293 pr_err("Cache object %lu xattr length incorrect\n",
David Howells9ae326a2009-04-03 16:42:41 +0100294 dentry->d_inode->i_ino);
295 ret = -EIO;
296 goto error;
297
298stale:
299 ret = -ESTALE;
300 goto error;
301}
302
303/*
304 * remove the object's xattr to mark it stale
305 */
306int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
307 struct dentry *dentry)
308{
309 int ret;
310
311 ret = vfs_removexattr(dentry, cachefiles_xattr_cache);
312 if (ret < 0) {
313 if (ret == -ENOENT || ret == -ENODATA)
314 ret = 0;
315 else if (ret != -ENOMEM)
316 cachefiles_io_error(cache,
317 "Can't remove xattr from %lu"
318 " (error %d)",
319 dentry->d_inode->i_ino, -ret);
320 }
321
322 _leave(" = %d", ret);
323 return ret;
324}