Staging: hv: fix smp problems in the hyperv core code
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / cachefiles / xattr.c
blobf3e7a0bf068b17cf4cb2e5a5f6fa701daf08d4e5
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 "internal.h"
21 static const char cachefiles_xattr_cache[] =
22 XATTR_USER_PREFIX "CacheFiles.cache";
25 * check the type label on an object
26 * - done using xattrs
28 int cachefiles_check_object_type(struct cachefiles_object *object)
30 struct dentry *dentry = object->dentry;
31 char type[3], xtype[3];
32 int ret;
34 ASSERT(dentry);
35 ASSERT(dentry->d_inode);
37 if (!object->fscache.cookie)
38 strcpy(type, "C3");
39 else
40 snprintf(type, 3, "%02x", object->fscache.cookie->def->type);
42 _enter("%p{%s}", object, type);
44 /* attempt to install a type label directly */
45 ret = vfs_setxattr(dentry, cachefiles_xattr_cache, type, 2,
46 XATTR_CREATE);
47 if (ret == 0) {
48 _debug("SET"); /* we succeeded */
49 goto error;
52 if (ret != -EEXIST) {
53 kerror("Can't set xattr on %*.*s [%lu] (err %d)",
54 dentry->d_name.len, dentry->d_name.len,
55 dentry->d_name.name, dentry->d_inode->i_ino,
56 -ret);
57 goto error;
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;
66 kerror("Can't read xattr on %*.*s [%lu] (err %d)",
67 dentry->d_name.len, dentry->d_name.len,
68 dentry->d_name.name, dentry->d_inode->i_ino,
69 -ret);
70 goto error;
73 /* check the type is what we're expecting */
74 if (ret != 2)
75 goto bad_type_length;
77 if (xtype[0] != type[0] || xtype[1] != type[1])
78 goto bad_type;
80 ret = 0;
82 error:
83 _leave(" = %d", ret);
84 return ret;
86 bad_type_length:
87 kerror("Cache object %lu type xattr length incorrect",
88 dentry->d_inode->i_ino);
89 ret = -EIO;
90 goto error;
92 bad_type:
93 xtype[2] = 0;
94 kerror("Cache object %*.*s [%lu] type %s not %s",
95 dentry->d_name.len, dentry->d_name.len,
96 dentry->d_name.name, dentry->d_inode->i_ino,
97 xtype, type);
98 ret = -EIO;
99 goto error;
103 * set the state xattr on a cache file
105 int cachefiles_set_object_xattr(struct cachefiles_object *object,
106 struct cachefiles_xattr *auxdata)
108 struct dentry *dentry = object->dentry;
109 int ret;
111 ASSERT(object->fscache.cookie);
112 ASSERT(dentry);
114 _enter("%p,#%d", object, auxdata->len);
116 /* attempt to install the cache metadata directly */
117 _debug("SET %s #%u", object->fscache.cookie->def->name, 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(object->fscache.cookie);
141 ASSERT(dentry);
143 _enter("%p,#%d", object, auxdata->len);
145 /* attempt to install the cache metadata directly */
146 _debug("SET %s #%u", object->fscache.cookie->def->name, auxdata->len);
148 ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
149 &auxdata->type, auxdata->len,
150 XATTR_REPLACE);
151 if (ret < 0 && ret != -ENOMEM)
152 cachefiles_io_error_obj(
153 object,
154 "Failed to update xattr with error %d", ret);
156 _leave(" = %d", ret);
157 return ret;
161 * check the state xattr on a cache file
162 * - return -ESTALE if the object should be deleted
164 int cachefiles_check_object_xattr(struct cachefiles_object *object,
165 struct cachefiles_xattr *auxdata)
167 struct cachefiles_xattr *auxbuf;
168 struct dentry *dentry = object->dentry;
169 int ret;
171 _enter("%p,#%d", object, auxdata->len);
173 ASSERT(dentry);
174 ASSERT(dentry->d_inode);
176 auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL);
177 if (!auxbuf) {
178 _leave(" = -ENOMEM");
179 return -ENOMEM;
182 /* read the current type label */
183 ret = vfs_getxattr(dentry, cachefiles_xattr_cache,
184 &auxbuf->type, 512 + 1);
185 if (ret < 0) {
186 if (ret == -ENODATA)
187 goto stale; /* no attribute - power went off
188 * mid-cull? */
190 if (ret == -ERANGE)
191 goto bad_type_length;
193 cachefiles_io_error_obj(object,
194 "Can't read xattr on %lu (err %d)",
195 dentry->d_inode->i_ino, -ret);
196 goto error;
199 /* check the on-disk object */
200 if (ret < 1)
201 goto bad_type_length;
203 if (auxbuf->type != auxdata->type)
204 goto stale;
206 auxbuf->len = ret;
208 /* consult the netfs */
209 if (object->fscache.cookie->def->check_aux) {
210 enum fscache_checkaux result;
211 unsigned int dlen;
213 dlen = auxbuf->len - 1;
215 _debug("checkaux %s #%u",
216 object->fscache.cookie->def->name, dlen);
218 result = fscache_check_aux(&object->fscache,
219 &auxbuf->data, dlen);
221 switch (result) {
222 /* entry okay as is */
223 case FSCACHE_CHECKAUX_OKAY:
224 goto okay;
226 /* entry requires update */
227 case FSCACHE_CHECKAUX_NEEDS_UPDATE:
228 break;
230 /* entry requires deletion */
231 case FSCACHE_CHECKAUX_OBSOLETE:
232 goto stale;
234 default:
235 BUG();
238 /* update the current label */
239 ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
240 &auxdata->type, auxdata->len,
241 XATTR_REPLACE);
242 if (ret < 0) {
243 cachefiles_io_error_obj(object,
244 "Can't update xattr on %lu"
245 " (error %d)",
246 dentry->d_inode->i_ino, -ret);
247 goto error;
251 okay:
252 ret = 0;
254 error:
255 kfree(auxbuf);
256 _leave(" = %d", ret);
257 return ret;
259 bad_type_length:
260 kerror("Cache object %lu xattr length incorrect",
261 dentry->d_inode->i_ino);
262 ret = -EIO;
263 goto error;
265 stale:
266 ret = -ESTALE;
267 goto error;
271 * remove the object's xattr to mark it stale
273 int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
274 struct dentry *dentry)
276 int ret;
278 ret = vfs_removexattr(dentry, cachefiles_xattr_cache);
279 if (ret < 0) {
280 if (ret == -ENOENT || ret == -ENODATA)
281 ret = 0;
282 else if (ret != -ENOMEM)
283 cachefiles_io_error(cache,
284 "Can't remove xattr from %lu"
285 " (error %d)",
286 dentry->d_inode->i_ino, -ret);
289 _leave(" = %d", ret);
290 return ret;