ceph: ensure Boolean options support both senses

Many ceph-related Boolean options offer the ability to both enable
and disable a feature.  For all those that don't offer this, add
a new option so that they do.

Note that ceph_show_options()--which reports mount options currently
in effect--only reports the option if it is different from the
default value.

Signed-off-by: Alex Elder <elder@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 621c322..cc91319 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -201,7 +201,9 @@
 	Opt_ip,
 	Opt_last_string,
 	/* string args above */
+	Opt_share,
 	Opt_noshare,
+	Opt_crc,
 	Opt_nocrc,
 };
 
@@ -217,7 +219,9 @@
 	{Opt_key, "key=%s"},
 	{Opt_ip, "ip=%s"},
 	/* string args above */
+	{Opt_share, "share"},
 	{Opt_noshare, "noshare"},
+	{Opt_crc, "crc"},
 	{Opt_nocrc, "nocrc"},
 	{-1, NULL}
 };
@@ -399,10 +403,16 @@
 			opt->mount_timeout = intval;
 			break;
 
+		case Opt_share:
+			opt->flags &= ~CEPH_OPT_NOSHARE;
+			break;
 		case Opt_noshare:
 			opt->flags |= CEPH_OPT_NOSHARE;
 			break;
 
+		case Opt_crc:
+			opt->flags &= ~CEPH_OPT_NOCRC;
+			break;
 		case Opt_nocrc:
 			opt->flags |= CEPH_OPT_NOCRC;
 			break;