ocfs2: move ocfs2_xattr_handlers and ocfs2_xattr_handler_map to .rodata

This makes it harder for accidental or malicious changes to
ocfs2_xattr_handlers or ocfs2_xattr_handler_map at runtime.

Cc: Mark Fasheh <[e-mail]>
Cc: Joel Becker <[e-mail]>
Cc: Joseph Qi <[e-mail]>
Cc: [e-mail]
Signed-off-by: Wedson Almeida Filho <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Christian Brauner <[e-mail]>

fs/ocfs2/xattr.c

···
 	.xv.xr_list.l_count = cpu_to_le16(1),
 };
 
-const struct xattr_handler *ocfs2_xattr_handlers[] = {
+const struct xattr_handler * const ocfs2_xattr_handlers[] = {
 	&ocfs2_xattr_user_handler,
 	&ocfs2_xattr_trusted_handler,
 	&ocfs2_xattr_security_handler,
 	NULL
 };
 
-static const struct xattr_handler *ocfs2_xattr_handler_map[OCFS2_XATTR_MAX] = {
+static const struct xattr_handler * const ocfs2_xattr_handler_map[OCFS2_XATTR_MAX] = {
 	[OCFS2_XATTR_INDEX_USER]		= &ocfs2_xattr_user_handler,
 	[OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS]	= &nop_posix_acl_access,
 	[OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT]	= &nop_posix_acl_default,

fs/ocfs2/xattr.h

···
 extern const struct xattr_handler ocfs2_xattr_user_handler;
 extern const struct xattr_handler ocfs2_xattr_trusted_handler;
 extern const struct xattr_handler ocfs2_xattr_security_handler;
-extern const struct xattr_handler *ocfs2_xattr_handlers[];
+extern const struct xattr_handler * const ocfs2_xattr_handlers[];
 
 ssize_t ocfs2_listxattr(struct dentry *, char *, size_t);
 int ocfs2_xattr_get_nolock(struct inode *, struct buffer_head *, int,