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>

4 files changed, 123 insertions, 79 deletions

diff --git a/include/linux/drbd_genl.h b/include/linux/drbd_genl.h
index a07d69279b1a..938e8560a833 100644
--- a/include/linux/drbd_genl.h
+++ b/include/linux/drbd_genl.h
@@ -102,66 +102,73 @@ GENL_struct(DRBD_NLA_CFG_CONTEXT, 2, drbd_cfg_context,
 )
 
 GENL_struct(DRBD_NLA_DISK_CONF, 3, disk_conf,
-        __u64_field(1, GENLA_F_MANDATORY,       disk_size)
-        __str_field(2, GENLA_F_REQUIRED,        backing_dev,    128)
-        __str_field(3, GENLA_F_REQUIRED,        meta_dev,       128)
-        __u32_field(4, GENLA_F_REQUIRED,        meta_dev_idx)
-        __u32_field(5, GENLA_F_MANDATORY,       max_bio_bvecs)
+        __str_field(1, GENLA_F_REQUIRED | GENLA_F_INVARIANT,    backing_dev,    128)
+        __str_field(2, GENLA_F_REQUIRED | GENLA_F_INVARIANT,    meta_dev,       128)
+        __u32_field(3, GENLA_F_REQUIRED | GENLA_F_INVARIANT,    meta_dev_idx)
+
+        /* use the resize command to try and change the disk_size */
+        __u64_field(4, GENLA_F_MANDATORY | GENLA_F_INVARIANT,   disk_size)
+        /* we could change the max_bio_bvecs,
+         * but it won't propagate through the stack */
+        __u32_field(5, GENLA_F_MANDATORY | GENLA_F_INVARIANT,   max_bio_bvecs)
+
         __u32_field(6, GENLA_F_MANDATORY,       on_io_error)
         __u32_field(7, GENLA_F_MANDATORY,       fencing)
-        __flg_field(8, GENLA_F_MANDATORY,       no_disk_barrier)
-        __flg_field(9, GENLA_F_MANDATORY,       no_disk_flush)
-        __flg_field(10, GENLA_F_MANDATORY,      no_disk_drain)
-        __flg_field(11, GENLA_F_MANDATORY,      no_md_flush)
-        __flg_field(12, GENLA_F_MANDATORY,      use_bmbv)
+
+        __u32_field(8,  GENLA_F_MANDATORY,      resync_rate)
+        __u32_field(9,  GENLA_F_MANDATORY,      resync_after)
+        __u32_field(10, GENLA_F_MANDATORY,      al_extents)
+        __u32_field(11, GENLA_F_MANDATORY,      c_plan_ahead)
+        __u32_field(12, GENLA_F_MANDATORY,      c_delay_target)
+        __u32_field(13, GENLA_F_MANDATORY,      c_fill_target)
+        __u32_field(14, GENLA_F_MANDATORY,      c_max_rate)
+        __u32_field(15, GENLA_F_MANDATORY,      c_min_rate)
+
+        __flg_field(16, GENLA_F_MANDATORY,      no_disk_barrier)
+        __flg_field(17, GENLA_F_MANDATORY,      no_disk_flush)
+        __flg_field(18, GENLA_F_MANDATORY,      no_disk_drain)
+        __flg_field(19, GENLA_F_MANDATORY,      no_md_flush)
+
 )
 
-GENL_struct(DRBD_NLA_SYNCER_CONF, 4, syncer_conf,
-        __u32_field(1,  GENLA_F_MANDATORY,      rate)
-        __u32_field(2,  GENLA_F_MANDATORY,      after)
-        __u32_field(3,  GENLA_F_MANDATORY,      al_extents)
-        __str_field(4,  GENLA_F_MANDATORY,      cpu_mask,       32)
-        __str_field(5,  GENLA_F_MANDATORY,      verify_alg,     SHARED_SECRET_MAX)
-        __str_field(6,  GENLA_F_MANDATORY,      csums_alg,      SHARED_SECRET_MAX)
-        __flg_field(7,  GENLA_F_MANDATORY,      use_rle)
-        __u32_field(8,  GENLA_F_MANDATORY,      on_no_data)
-        __u32_field(9,  GENLA_F_MANDATORY,      c_plan_ahead)
-        __u32_field(10, GENLA_F_MANDATORY,      c_delay_target)
-        __u32_field(11, GENLA_F_MANDATORY,      c_fill_target)
-        __u32_field(12, GENLA_F_MANDATORY,      c_max_rate)
-        __u32_field(13, GENLA_F_MANDATORY,      c_min_rate)
+GENL_struct(DRBD_NLA_RESOURCE_OPTS, 4, res_opts,
+        __str_field(1,  GENLA_F_MANDATORY,      cpu_mask,       32)
+        __u32_field(2,  GENLA_F_MANDATORY,      on_no_data)
 )
 
 GENL_struct(DRBD_NLA_NET_CONF, 5, net_conf,
-        __str_field(1,  GENLA_F_MANDATORY | GENLA_F_SENSITIVE,
+        __bin_field(1,  GENLA_F_REQUIRED | GENLA_F_INVARIANT,   my_addr,        128)
+        __bin_field(2,  GENLA_F_REQUIRED | GENLA_F_INVARIANT,   peer_addr,      128)
+        __str_field(3,  GENLA_F_MANDATORY | GENLA_F_SENSITIVE,
                                                 shared_secret,  SHARED_SECRET_MAX)
-        __str_field(2,  GENLA_F_MANDATORY,      cram_hmac_alg,  SHARED_SECRET_MAX)
-        __str_field(3,  GENLA_F_MANDATORY,      integrity_alg,  SHARED_SECRET_MAX)
-        __str_field(4,  GENLA_F_REQUIRED,       my_addr,        128)
-        __str_field(5,  GENLA_F_REQUIRED,       peer_addr,      128)
-        __u32_field(6,  GENLA_F_REQUIRED,       wire_protocol)
-        __u32_field(7,  GENLA_F_MANDATORY,      try_connect_int)
-        __u32_field(8,  GENLA_F_MANDATORY,      timeout)
-        __u32_field(9,  GENLA_F_MANDATORY,      ping_int)
-        __u32_field(10, GENLA_F_MANDATORY,      ping_timeo)
-        __u32_field(11, GENLA_F_MANDATORY,      sndbuf_size)
-        __u32_field(12, GENLA_F_MANDATORY,      rcvbuf_size)
-        __u32_field(13, GENLA_F_MANDATORY,      ko_count)
-        __u32_field(14, GENLA_F_MANDATORY,      max_buffers)
-        __u32_field(15, GENLA_F_MANDATORY,      max_epoch_size)
-        __u32_field(16, GENLA_F_MANDATORY,      unplug_watermark)
-        __u32_field(17, GENLA_F_MANDATORY,      after_sb_0p)
-        __u32_field(18, GENLA_F_MANDATORY,      after_sb_1p)
-        __u32_field(19, GENLA_F_MANDATORY,      after_sb_2p)
-        __u32_field(20, GENLA_F_MANDATORY,      rr_conflict)
-        __u32_field(21, GENLA_F_MANDATORY,      on_congestion)
-        __u32_field(22, GENLA_F_MANDATORY,      cong_fill)
-        __u32_field(23, GENLA_F_MANDATORY,      cong_extents)
-        __flg_field(24, GENLA_F_MANDATORY,      two_primaries)
-        __flg_field(25, GENLA_F_MANDATORY,      want_lose)
-        __flg_field(26, GENLA_F_MANDATORY,      no_cork)
-        __flg_field(27, GENLA_F_MANDATORY,      always_asbp)
-        __flg_field(28, GENLA_F_MANDATORY,      dry_run)
+        __str_field(4,  GENLA_F_MANDATORY,      cram_hmac_alg,  SHARED_SECRET_MAX)
+        __str_field(5,  GENLA_F_MANDATORY,      integrity_alg,  SHARED_SECRET_MAX)
+        __str_field(6,  GENLA_F_MANDATORY,      verify_alg,     SHARED_SECRET_MAX)
+        __str_field(7,  GENLA_F_MANDATORY,      csums_alg,      SHARED_SECRET_MAX)
+        __u32_field(8,  GENLA_F_MANDATORY,      wire_protocol)
+        __u32_field(9,  GENLA_F_MANDATORY,      try_connect_int)
+        __u32_field(10, GENLA_F_MANDATORY,      timeout)
+        __u32_field(11, GENLA_F_MANDATORY,      ping_int)
+        __u32_field(12, GENLA_F_MANDATORY,      ping_timeo)
+        __u32_field(13, GENLA_F_MANDATORY,      sndbuf_size)
+        __u32_field(14, GENLA_F_MANDATORY,      rcvbuf_size)
+        __u32_field(15, GENLA_F_MANDATORY,      ko_count)
+        __u32_field(16, GENLA_F_MANDATORY,      max_buffers)
+        __u32_field(17, GENLA_F_MANDATORY,      max_epoch_size)
+        __u32_field(18, GENLA_F_MANDATORY,      unplug_watermark)
+        __u32_field(19, GENLA_F_MANDATORY,      after_sb_0p)
+        __u32_field(20, GENLA_F_MANDATORY,      after_sb_1p)
+        __u32_field(21, GENLA_F_MANDATORY,      after_sb_2p)
+        __u32_field(22, GENLA_F_MANDATORY,      rr_conflict)
+        __u32_field(23, GENLA_F_MANDATORY,      on_congestion)
+        __u32_field(24, GENLA_F_MANDATORY,      cong_fill)
+        __u32_field(25, GENLA_F_MANDATORY,      cong_extents)
+        __flg_field(26, GENLA_F_MANDATORY,      two_primaries)
+        __flg_field(27, GENLA_F_MANDATORY | GENLA_F_INVARIANT,  want_lose)
+        __flg_field(28, GENLA_F_MANDATORY,      no_cork)
+        __flg_field(29, GENLA_F_MANDATORY,      always_asbp)
+        __flg_field(30, GENLA_F_MANDATORY | GENLA_F_INVARIANT,  dry_run)
+        __flg_field(31, GENLA_F_MANDATORY,      use_rle)
 )
 
 GENL_struct(DRBD_NLA_SET_ROLE_PARMS, 6, set_role_parms,
@@ -270,11 +277,10 @@ GENL_op(DRBD_ADM_ADD_LINK, 7, GENL_doit(drbd_adm_create_connection),
 GENL_op(DRBD_ADM_DEL_LINK, 8, GENL_doit(drbd_adm_delete_connection),
         GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
 
-        /* operates on replication links */
-GENL_op(DRBD_ADM_SYNCER, 9,
-        GENL_doit(drbd_adm_syncer),
+GENL_op(DRBD_ADM_RESOURCE_OPTS, 9,
+        GENL_doit(drbd_adm_resource_opts),
         GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
-        GENL_tla_expected(DRBD_NLA_SYNCER_CONF, GENLA_F_MANDATORY)
+        GENL_tla_expected(DRBD_NLA_RESOURCE_OPTS, GENLA_F_MANDATORY)
 )
 
 GENL_op(
@@ -284,16 +290,28 @@ GENL_op(
         GENL_tla_expected(DRBD_NLA_NET_CONF, GENLA_F_REQUIRED)
 )
 
+GENL_op(
+        DRBD_ADM_CHG_NET_OPTS, 29,
+        GENL_doit(drbd_adm_net_opts),
+        GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
+        GENL_tla_expected(DRBD_NLA_NET_CONF, GENLA_F_REQUIRED)
+)
+
 GENL_op(DRBD_ADM_DISCONNECT, 11, GENL_doit(drbd_adm_disconnect),
         GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
 
-        /* operates on minors */
 GENL_op(DRBD_ADM_ATTACH, 12,
         GENL_doit(drbd_adm_attach),
         GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
         GENL_tla_expected(DRBD_NLA_DISK_CONF, GENLA_F_REQUIRED)
 )
 
+GENL_op(DRBD_ADM_CHG_DISK_OPTS, 28,
+        GENL_doit(drbd_adm_disk_opts),
+        GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
+        GENL_tla_expected(DRBD_NLA_DISK_OPTS, GENLA_F_REQUIRED)
+)
+
 GENL_op(
         DRBD_ADM_RESIZE, 13,
         GENL_doit(drbd_adm_resize),
@@ -301,7 +319,6 @@ GENL_op(
         GENL_tla_expected(DRBD_NLA_RESIZE_PARMS, GENLA_F_MANDATORY)
 )
 
-        /* operates on all volumes within a resource */
 GENL_op(
         DRBD_ADM_PRIMARY, 14,
         GENL_doit(drbd_adm_set_role),
diff --git a/include/linux/drbd_limits.h b/include/linux/drbd_limits.h
index 22920a8af4e2..659a8eb38830 100644
--- a/include/linux/drbd_limits.h
+++ b/include/linux/drbd_limits.h
@@ -166,5 +166,7 @@
 #define DRBD_CONG_EXTENTS_MAX   DRBD_AL_EXTENTS_MAX
 #define DRBD_CONG_EXTENTS_DEF   DRBD_AL_EXTENTS_DEF
 
+#define DRBD_PROTOCOL_DEF DRBD_PROT_C
+
 #undef RANGE
 #endif
diff --git a/include/linux/genl_magic_func.h b/include/linux/genl_magic_func.h
index c8c67239f616..e458282a3728 100644
--- a/include/linux/genl_magic_func.h
+++ b/include/linux/genl_magic_func.h
@@ -190,11 +190,12 @@ static struct nlattr *nested_attr_tb[128];
 
 #undef GENL_struct
 #define GENL_struct(tag_name, tag_number, s_name, s_fields)             \
-        /* static, potentially unused */                                \
-int s_name ## _from_attrs(struct s_name *s, struct nlattr *tb[])        \
+/* *_from_attrs functions are static, but potentially unused */         \
+static int __ ## s_name ## _from_attrs(struct s_name *s,                \
+                struct genl_info *info, bool exclude_invariants)        \
 {                                                                       \
         const int maxtype = ARRAY_SIZE(s_name ## _nl_policy)-1;         \
-        struct nlattr *tla = tb[tag_number];                            \
+        struct nlattr *tla = info->attrs[tag_number];                   \
         struct nlattr **ntb = nested_attr_tb;                           \
         struct nlattr *nla;                                             \
         int err;                                                        \
@@ -211,33 +212,49 @@ int s_name ## _from_attrs(struct s_name *s, struct nlattr *tb[])	\
                                                                         \
         s_fields                                                        \
         return 0;                                                       \
-}
+}                                       __attribute__((unused))         \
+static int s_name ## _from_attrs(struct s_name *s,                      \
+                                                struct genl_info *info) \
+{                                                                       \
+        return __ ## s_name ## _from_attrs(s, info, false);             \
+}                                       __attribute__((unused))         \
+static int s_name ## _from_attrs_for_change(struct s_name *s,           \
+                                                struct genl_info *info) \
+{                                                                       \
+        return __ ## s_name ## _from_attrs(s, info, true);              \
+}                                       __attribute__((unused))         \
 
-#undef __field
-#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \
+#define __assign(attr_nr, attr_flag, name, nla_type, type, assignment...)       \
                 nla = ntb[__nla_type(attr_nr)];                         \
                 if (nla) {                                              \
-                        if (s)                                          \
-                                s->name = __get(nla);                   \
-                        DPRINT_FIELD("<<", nla_type, name, s, nla);     \
+                        if (exclude_invariants && ((attr_flag) & GENLA_F_INVARIANT)) {          \
+                                pr_info("<< must not change invariant attr: %s\n", #name);      \
+                                return -EEXIST;                         \
+                        }                                               \
+                        assignment;                                     \
+                } else if (exclude_invariants && ((attr_flag) & GENLA_F_INVARIANT)) {           \
+                        /* attribute missing from payload, */           \
+                        /* which was expected */                        \
                 } else if ((attr_flag) & GENLA_F_REQUIRED) {            \
                         pr_info("<< missing attr: %s\n", #name);        \
                         return -ENOMSG;                                 \
                 }
 
+#undef __field
+#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \
+        __assign(attr_nr, attr_flag, name, nla_type, type,              \
+                        if (s)                                          \
+                                s->name = __get(nla);                   \
+                        DPRINT_FIELD("<<", nla_type, name, s, nla))
+
 /* validate_nla() already checked nla_len <= maxlen appropriately. */
 #undef __array
 #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \
-                nla = ntb[__nla_type(attr_nr)];                         \
-                if (nla) {                                              \
+        __assign(attr_nr, attr_flag, name, nla_type, type,              \
                         if (s)                                          \
                                 s->name ## _len =                       \
                                         __get(s->name, nla, maxlen);    \
-                        DPRINT_ARRAY("<<", nla_type, name, s, nla);     \
-                } else if ((attr_flag) & GENLA_F_REQUIRED) {            \
-                        pr_info("<< missing attr: %s\n", #name);        \
-                        return -ENOMSG;                                 \
-                }                                                       \
+                        DPRINT_ARRAY("<<", nla_type, name, s, nla))
 
 #include GENL_MAGIC_INCLUDE_FILE
 
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))