CacheFiles: Implement interface to check cache consistency
Implement the FS-Cache interface to check the consistency of a cache object in
CacheFiles.
Original-author: Hongyi Jia <jiayisuse@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hongyi Jia <jiayisuse@gmail.com>
cc: Milosz Tanski <milosz@adfin.com>
diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c
index 2476e51..34c88b8 100644
--- a/fs/cachefiles/xattr.c
+++ b/fs/cachefiles/xattr.c
@@ -157,6 +157,42 @@
}
/*
+ * check the consistency between the backing cache and the FS-Cache cookie
+ */
+int cachefiles_check_auxdata(struct cachefiles_object *object)
+{
+ struct cachefiles_xattr *auxbuf;
+ struct dentry *dentry = object->dentry;
+ unsigned int dlen;
+ int ret;
+
+ ASSERT(dentry);
+ ASSERT(dentry->d_inode);
+ ASSERT(object->fscache.cookie->def->check_aux);
+
+ auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL);
+ if (!auxbuf)
+ return -ENOMEM;
+
+ auxbuf->len = vfs_getxattr(dentry, cachefiles_xattr_cache,
+ &auxbuf->type, 512 + 1);
+ if (auxbuf->len < 1)
+ return -ESTALE;
+
+ if (auxbuf->type != object->fscache.cookie->def->type)
+ return -ESTALE;
+
+ dlen = auxbuf->len - 1;
+ ret = fscache_check_aux(&object->fscache, &auxbuf->data, dlen);
+
+ kfree(auxbuf);
+ if (ret != FSCACHE_CHECKAUX_OKAY)
+ return -ESTALE;
+
+ return 0;
+}
+
+/*
* check the state xattr on a cache file
* - return -ESTALE if the object should be deleted
*/