drbd: receive_protocol(): We cannot change our own data-integrity-alg setting here

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

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index aa674bf8a10b38e01bc6355df93029ed2f3dfffd..68a5abaf5ea338797ac6c15b5235f100bffd5e9b 100644 (file)
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3002,7 +3002,7 @@ static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi)
        int p_proto, p_discard_my_data, p_two_primaries, cf;
        struct net_conf *nc, *old_net_conf, *new_net_conf = NULL;
        char integrity_alg[SHARED_SECRET_MAX] = "";
-       struct crypto_hash *peer_integrity_tfm = NULL, *integrity_tfm = NULL;
+       struct crypto_hash *peer_integrity_tfm = NULL;
        void *int_dig_in = NULL, *int_dig_vv = NULL;
 
        p_proto         = be32_to_cpu(p->protocol);
@@ -3028,15 +3028,23 @@ static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi)
                if (integrity_alg[0]) {
                        int hash_size;
 
+                       /*
+                        * We can only change the peer data integrity algorithm
+                        * here.  Changing our own data integrity algorithm
+                        * requires that we send a P_PROTOCOL_UPDATE packet at
+                        * the same time; otherwise, the peer has no way to
+                        * tell between which packets the algorithm should
+                        * change.
+                        */
+
                        peer_integrity_tfm = crypto_alloc_hash(integrity_alg, 0, CRYPTO_ALG_ASYNC);
-                       integrity_tfm = crypto_alloc_hash(integrity_alg, 0, CRYPTO_ALG_ASYNC);
-                       if (!(peer_integrity_tfm && integrity_tfm)) {
+                       if (!peer_integrity_tfm) {
                                conn_err(tconn, "peer data-integrity-alg %s not supported\n",
                                         integrity_alg);
                                goto disconnect;
                        }
 
-                       hash_size = crypto_hash_digestsize(integrity_tfm);
+                       hash_size = crypto_hash_digestsize(peer_integrity_tfm);
                        int_dig_in = kmalloc(hash_size, GFP_KERNEL);
                        int_dig_vv = kmalloc(hash_size, GFP_KERNEL);
                        if (!(int_dig_in && int_dig_vv)) {
@@ -3064,9 +3072,6 @@ static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi)
                strcpy(new_net_conf->integrity_alg, integrity_alg);
                new_net_conf->integrity_alg_len = strlen(integrity_alg) + 1;
 
-               crypto_free_hash(tconn->integrity_tfm);
-               tconn->integrity_tfm = integrity_tfm;
-
                rcu_assign_pointer(tconn->net_conf, new_net_conf);
                mutex_unlock(&tconn->conf_update);
                mutex_unlock(&tconn->data.mutex);
@@ -3079,7 +3084,8 @@ static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi)
                tconn->int_dig_vv = int_dig_vv;
 
                if (strcmp(old_net_conf->integrity_alg, integrity_alg))
-                       conn_info(tconn, "peer data-integrity-alg: %s\n", integrity_alg);
+                       conn_info(tconn, "peer data-integrity-alg: %s\n",
+                                 integrity_alg[0] ? integrity_alg : "(none)");
 
                synchronize_rcu();
                kfree(old_net_conf);
@@ -3135,7 +3141,6 @@ disconnect_rcu_unlock:
        rcu_read_unlock();
 disconnect:
        crypto_free_hash(peer_integrity_tfm);
-       crypto_free_hash(integrity_tfm);
        kfree(int_dig_in);
        kfree(int_dig_vv);
        conn_request_state(tconn, NS(conn, C_DISCONNECTING), CS_HARD);