hyperv: Add processing of MTU reduced by the host
[linux/fpc-iii.git] / fs / cachefiles / xattr.c
blobacbc1f094fb1a418ed489538c85122c609052bd0
1 /* CacheFiles extended attribute management
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
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>
19 #include <linux/slab.h>
20 #include "internal.h"
22 static const char cachefiles_xattr_cache[] =
23 XATTR_USER_PREFIX "CacheFiles.cache";
26 * check the type label on an object
27 * - done using xattrs
29 int cachefiles_check_object_type(struct cachefiles_object *object)
31 struct dentry *dentry = object->dentry;
32 char type[3], xtype[3];
33 int ret;
35 ASSERT(dentry);
36 ASSERT(dentry->d_inode);
38 if (!object->fscache.cookie)
39 strcpy(type, "C3");
40 else
41 snprintf(type, 3, "%02x", object->fscache.cookie->def->type);
43 _enter("%p{%s}", object, type);
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;
53 if (ret != -EEXIST) {
54 pr_err("Can't set xattr on %*.*s [%lu] (err %d)\n",
55 dentry->d_name.len, dentry->d_name.len,
56 dentry->d_name.name, dentry->d_inode->i_ino,
57 -ret);
58 goto error;
61 /* read the current type label */
62 ret = vfs_getxattr(dentry, cachefiles_xattr_cache, xtype, 3);
63 if (ret < 0) {
64 if (ret == -ERANGE)
65 goto bad_type_length;
67 pr_err("Can't read xattr on %*.*s [%lu] (err %d)\n",
68 dentry->d_name.len, dentry->d_name.len,
69 dentry->d_name.name, dentry->d_inode->i_ino,
70 -ret);
71 goto error;
74 /* check the type is what we're expecting */
75 if (ret != 2)
76 goto bad_type_length;
78 if (xtype[0] != type[0] || xtype[1] != type[1])
79 goto bad_type;
81 ret = 0;
83 error:
84 _leave(" = %d", ret);
85 return ret;
87 bad_type_length:
88 pr_err("Cache object %lu type xattr length incorrect\n",
89 dentry->d_inode->i_ino);
90 ret = -EIO;
91 goto error;
93 bad_type:
94 xtype[2] = 0;
95 pr_err("Cache object %*.*s [%lu] type %s not %s\n",
96 dentry->d_name.len, dentry->d_name.len,
97 dentry->d_name.name, dentry->d_inode->i_ino,
98 xtype, type);
99 ret = -EIO;
100 goto error;
104 * set the state xattr on a cache file
106 int cachefiles_set_object_xattr(struct cachefiles_object *object,
107 struct cachefiles_xattr *auxdata)
109 struct dentry *dentry = object->dentry;
110 int ret;
112 ASSERT(dentry);
114 _enter("%p,#%d", object, auxdata->len);
116 /* attempt to install the cache metadata directly */
117 _debug("SET #%u", auxdata->len);
119 ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
120 &auxdata->type, auxdata->len,
121 XATTR_CREATE);
122 if (ret < 0 && ret != -ENOMEM)
123 cachefiles_io_error_obj(
124 object,
125 "Failed to set xattr with error %d", ret);
127 _leave(" = %d", ret);
128 return ret;
132 * update the state xattr on a cache file
134 int cachefiles_update_object_xattr(struct cachefiles_object *object,
135 struct cachefiles_xattr *auxdata)
137 struct dentry *dentry = object->dentry;
138 int ret;
140 ASSERT(dentry);
142 _enter("%p,#%d", object, auxdata->len);
144 /* attempt to install the cache metadata directly */
145 _debug("SET #%u", auxdata->len);
147 ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
148 &auxdata->type, auxdata->len,
149 XATTR_REPLACE);
150 if (ret < 0 && ret != -ENOMEM)
151 cachefiles_io_error_obj(
152 object,
153 "Failed to update xattr with error %d", ret);
155 _leave(" = %d", ret);
156 return ret;
160 * check the consistency between the backing cache and the FS-Cache cookie
162 int cachefiles_check_auxdata(struct cachefiles_object *object)
164 struct cachefiles_xattr *auxbuf;
165 enum fscache_checkaux validity;
166 struct dentry *dentry = object->dentry;
167 ssize_t xlen;
168 int ret;
170 ASSERT(dentry);
171 ASSERT(dentry->d_inode);
172 ASSERT(object->fscache.cookie->def->check_aux);
174 auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL);
175 if (!auxbuf)
176 return -ENOMEM;
178 xlen = vfs_getxattr(dentry, cachefiles_xattr_cache,
179 &auxbuf->type, 512 + 1);
180 ret = -ESTALE;
181 if (xlen < 1 ||
182 auxbuf->type != object->fscache.cookie->def->type)
183 goto error;
185 xlen--;
186 validity = fscache_check_aux(&object->fscache, &auxbuf->data, xlen);
187 if (validity != FSCACHE_CHECKAUX_OKAY)
188 goto error;
190 ret = 0;
191 error:
192 kfree(auxbuf);
193 return ret;
197 * check the state xattr on a cache file
198 * - return -ESTALE if the object should be deleted
200 int cachefiles_check_object_xattr(struct cachefiles_object *object,
201 struct cachefiles_xattr *auxdata)
203 struct cachefiles_xattr *auxbuf;
204 struct dentry *dentry = object->dentry;
205 int ret;
207 _enter("%p,#%d", object, auxdata->len);
209 ASSERT(dentry);
210 ASSERT(dentry->d_inode);
212 auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, cachefiles_gfp);
213 if (!auxbuf) {
214 _leave(" = -ENOMEM");
215 return -ENOMEM;
218 /* read the current type label */
219 ret = vfs_getxattr(dentry, cachefiles_xattr_cache,
220 &auxbuf->type, 512 + 1);
221 if (ret < 0) {
222 if (ret == -ENODATA)
223 goto stale; /* no attribute - power went off
224 * mid-cull? */
226 if (ret == -ERANGE)
227 goto bad_type_length;
229 cachefiles_io_error_obj(object,
230 "Can't read xattr on %lu (err %d)",
231 dentry->d_inode->i_ino, -ret);
232 goto error;
235 /* check the on-disk object */
236 if (ret < 1)
237 goto bad_type_length;
239 if (auxbuf->type != auxdata->type)
240 goto stale;
242 auxbuf->len = ret;
244 /* consult the netfs */
245 if (object->fscache.cookie->def->check_aux) {
246 enum fscache_checkaux result;
247 unsigned int dlen;
249 dlen = auxbuf->len - 1;
251 _debug("checkaux %s #%u",
252 object->fscache.cookie->def->name, dlen);
254 result = fscache_check_aux(&object->fscache,
255 &auxbuf->data, dlen);
257 switch (result) {
258 /* entry okay as is */
259 case FSCACHE_CHECKAUX_OKAY:
260 goto okay;
262 /* entry requires update */
263 case FSCACHE_CHECKAUX_NEEDS_UPDATE:
264 break;
266 /* entry requires deletion */
267 case FSCACHE_CHECKAUX_OBSOLETE:
268 goto stale;
270 default:
271 BUG();
274 /* update the current label */
275 ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
276 &auxdata->type, auxdata->len,
277 XATTR_REPLACE);
278 if (ret < 0) {
279 cachefiles_io_error_obj(object,
280 "Can't update xattr on %lu"
281 " (error %d)",
282 dentry->d_inode->i_ino, -ret);
283 goto error;
287 okay:
288 ret = 0;
290 error:
291 kfree(auxbuf);
292 _leave(" = %d", ret);
293 return ret;
295 bad_type_length:
296 pr_err("Cache object %lu xattr length incorrect\n",
297 dentry->d_inode->i_ino);
298 ret = -EIO;
299 goto error;
301 stale:
302 ret = -ESTALE;
303 goto error;
307 * remove the object's xattr to mark it stale
309 int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
310 struct dentry *dentry)
312 int ret;
314 ret = vfs_removexattr(dentry, cachefiles_xattr_cache);
315 if (ret < 0) {
316 if (ret == -ENOENT || ret == -ENODATA)
317 ret = 0;
318 else if (ret != -ENOMEM)
319 cachefiles_io_error(cache,
320 "Can't remove xattr from %lu"
321 " (error %d)",
322 dentry->d_inode->i_ino, -ret);
325 _leave(" = %d", ret);
326 return ret;