drbd: distribute former syncer_conf settings to disk, connection, and resource level

This commit breaks the API again.

Move per-volume former syncer options into disk_conf.
Move per-connection former syncer options into net_conf.
Renamed the remainign sync_conf to res_opts

Syncer settings have been changeable at runtime, so we need to prepare
for these settings to be runtime-changeable in their new home as well.

Introduce new configuration operations, and share the netlink attribute
between "attach" (create new disk) and "disk-opts" (change options).
Same for "connect" and "net-opts".

Some fields cannot be changed at runtime, however.
Introduce a new flag GENLA_F_INVARIANT to be able to trigger on that in
the generated validation and assignment functions.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 13 insertions, 5 deletions

diff --git a/include/linux/genl_magic_struct.h b/include/linux/genl_magic_struct.h
index 745ebfd6c7e5..9a605b9ee834 100644
--- a/include/linux/genl_magic_struct.h
+++ b/include/linux/genl_magic_struct.h
@@ -59,12 +59,20 @@ enum {
         GENLA_F_MANDATORY       = 1 << 14,
         GENLA_F_REQUIRED        = 1 << 15,
 
-        /* This will not be present in the __u16 .nla_type, but can be
-         * triggered on in <struct>_to_skb, to exclude "sensitive"
-         * information from broadcasts, or on unpriviledged get requests.
-         * This is useful because genetlink multicast groups can be listened in
-         * on by anyone.  */
+        /* Below will not be present in the __u16 .nla_type, but can be
+         * triggered on in <struct>_to_skb resp. <struct>_from_attrs */
+
+        /* To exclude "sensitive" information from broadcasts, or on
+         * unpriviledged get requests.  This is useful because genetlink
+         * multicast groups can be listened in on by anyone.  */
         GENLA_F_SENSITIVE       = 1 << 16,
+
+        /* INVARIAN options cannot be changed at runtime.
+         * Useful to share an attribute policy and struct definition,
+         * between some "create" and "change" commands,
+         * but disallow certain fields to be changed online.
+         */
+        GENLA_F_INVARIANT       = 1 << 17,
 };
 
 #define __nla_type(x)   ((__u16)((__u16)(x) & (__u16)NLA_TYPE_MASK))