fs/9p: xattr: add trusted and security namespaces
Allow requests for security.* and trusted.* xattr name spaces
to pass through to server.
The new files are 99% cut and paste from fs/9p/xattr_user.c with the
namespaces changed. It has the intended effect in superficial testing.
I do not know much detail about how these namespaces are used, but passing
them through to the server, which can decide whether to handle them or not,
seems reasonable.
I want to support a use case where an ext4 file system is mounted via 9P,
then re-exported via samba to windows clients in a cluster. Windows wants
to store xattrs such as security.NTACL. This works when ext4 directly
backs samba, but not when 9P is inserted. This use case is documented here:
http://code.google.com/p/diod/issues/detail?id=95
Signed-off-by: Jim Garlick <garlick@llnl.gov>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/fs/9p/xattr_trusted.c b/fs/9p/xattr_trusted.c
new file mode 100644
index 0000000..e30d33b
--- /dev/null
+++ b/fs/9p/xattr_trusted.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include "xattr.h"
+
+static int v9fs_xattr_trusted_get(struct dentry *dentry, const char *name,
+ void *buffer, size_t size, int type)
+{
+ int retval;
+ char *full_name;
+ size_t name_len;
+ size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
+
+ if (name == NULL)
+ return -EINVAL;
+
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+
+ name_len = strlen(name);
+ full_name = kmalloc(prefix_len + name_len + 1 , GFP_KERNEL);
+ if (!full_name)
+ return -ENOMEM;
+ memcpy(full_name, XATTR_TRUSTED_PREFIX, prefix_len);
+ memcpy(full_name+prefix_len, name, name_len);
+ full_name[prefix_len + name_len] = '\0';
+
+ retval = v9fs_xattr_get(dentry, full_name, buffer, size);
+ kfree(full_name);
+ return retval;
+}
+
+static int v9fs_xattr_trusted_set(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags, int type)
+{
+ int retval;
+ char *full_name;
+ size_t name_len;
+ size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
+
+ if (name == NULL)
+ return -EINVAL;
+
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+
+ name_len = strlen(name);
+ full_name = kmalloc(prefix_len + name_len + 1 , GFP_KERNEL);
+ if (!full_name)
+ return -ENOMEM;
+ memcpy(full_name, XATTR_TRUSTED_PREFIX, prefix_len);
+ memcpy(full_name + prefix_len, name, name_len);
+ full_name[prefix_len + name_len] = '\0';
+
+ retval = v9fs_xattr_set(dentry, full_name, value, size, flags);
+ kfree(full_name);
+ return retval;
+}
+
+struct xattr_handler v9fs_xattr_trusted_handler = {
+ .prefix = XATTR_TRUSTED_PREFIX,
+ .get = v9fs_xattr_trusted_get,
+ .set = v9fs_xattr_trusted_set,
+};