Commit 88104ca4 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Philipp Reisner
Browse files

drbd: Allow to change data-integrity-alg on the fly 



The main purpose of this is to allow to turn data integrity checking on
and off on demand without causing interruptions.

Implemented by allocating tconn->peer_integrity_tfm only when receiving
a P_PROTOCOL message.  l accesses to tconn->peer_integrity_tf happen in
worker context, and no further synchronization is necessary.

On the sender side, tconn->integrity_tfm is modified under
tconn->data.mutex, and a P_PROTOCOL message is sent whenever.  All
accesses to tconn->integrity_tfm already happen under this mutex.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent a7eb7bdf

drivers/block/drbd/drbd_main.c

+2 −2
Original line number Diff line number Diff line
@@ -1433,8 +1433,8 @@ static int _drbd_send_ack(struct drbd_conf *mdev, enum drbd_packet cmd, 
void drbd_send_ack_dp(struct drbd_conf *mdev, enum drbd_packet cmd,

		      struct p_data *dp, int data_size)

{

	data_size -= (mdev->tconn->agreed_pro_version >= 87 && mdev->tconn->peer_integrity_tfm) ?

		crypto_hash_digestsize(mdev->tconn->peer_integrity_tfm) : 0;

	if (mdev->tconn->peer_integrity_tfm)

		data_size -= crypto_hash_digestsize(mdev->tconn->peer_integrity_tfm);

	_drbd_send_ack(mdev, cmd, dp->sector, cpu_to_be32(data_size),

		       dp->block_id);

}

drivers/block/drbd/drbd_nl.c

+12 −10
Original line number Diff line number Diff line
@@ -1793,7 +1793,6 @@ struct crypto { 
	struct crypto_hash *csums_tfm;

	struct crypto_hash *cram_hmac_tfm;

	struct crypto_hash *integrity_tfm;

	struct crypto_hash *peer_integrity_tfm;

	void *int_dig_in;

	void *int_dig_vv;

};
@@ -1832,10 +1831,6 @@ alloc_crypto(struct crypto *crypto, struct net_conf *new_conf) 
		       ERR_INTEGRITY_ALG);

	if (rv != NO_ERROR)

		return rv;

	rv = alloc_hash(&crypto->peer_integrity_tfm, new_conf->integrity_alg,

		       ERR_INTEGRITY_ALG);

	if (rv != NO_ERROR)

		return rv;

	if (new_conf->cram_hmac_alg[0] != 0) {

		snprintf(hmac_name, CRYPTO_MAX_ALG_NAME, "hmac(%s)",

			 new_conf->cram_hmac_alg);
@@ -1862,7 +1857,6 @@ static void free_crypto(struct crypto *crypto) 
	kfree(crypto->int_dig_vv);

	crypto_free_hash(crypto->cram_hmac_tfm);

	crypto_free_hash(crypto->integrity_tfm);

	crypto_free_hash(crypto->peer_integrity_tfm);

	crypto_free_hash(crypto->csums_tfm);

	crypto_free_hash(crypto->verify_tfm);

}
@@ -1876,6 +1870,7 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info) 
	int ovr; /* online verify running */

	int rsr; /* re-sync running */

	struct crypto crypto = { };

	bool change_integrity_alg;



	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_CONN);

	if (!adm_ctx.reply_skb)
@@ -1893,6 +1888,7 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info) 


	conn_reconfig_start(tconn);



	mutex_lock(&tconn->data.mutex);

	mutex_lock(&tconn->net_conf_update);

	old_conf = tconn->net_conf;
@@ -1931,6 +1927,9 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info) 
		goto fail;

	}



	change_integrity_alg = strcmp(old_conf->integrity_alg,

				      new_conf->integrity_alg);



	retcode = alloc_crypto(&crypto, new_conf);

	if (retcode != NO_ERROR)

		goto fail;
@@ -1948,21 +1947,24 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info) 
		crypto.verify_tfm = NULL;

	}



	/* FIXME can not assign these so bluntly while we have ongoing IO */

	kfree(tconn->int_dig_in);

	tconn->int_dig_in = crypto.int_dig_in;

	kfree(tconn->int_dig_vv);

	tconn->int_dig_vv = crypto.int_dig_vv;

	crypto_free_hash(tconn->integrity_tfm);

	tconn->integrity_tfm = crypto.integrity_tfm;

	crypto_free_hash(tconn->peer_integrity_tfm);

	tconn->peer_integrity_tfm = crypto.peer_integrity_tfm;

	if (change_integrity_alg) {

		/* Do this without trying to take tconn->data.mutex again.  */

		if (__drbd_send_protocol(tconn))

			goto fail;

	}



	/* FIXME Changing cram_hmac while the connection is established is useless */

	crypto_free_hash(tconn->cram_hmac_tfm);

	tconn->cram_hmac_tfm = crypto.cram_hmac_tfm;



	mutex_unlock(&tconn->net_conf_update);

	mutex_unlock(&tconn->data.mutex);

	synchronize_rcu();

	kfree(old_conf);
@@ -1973,6 +1975,7 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info) 


 fail:

	mutex_unlock(&tconn->net_conf_update);

	mutex_unlock(&tconn->data.mutex);

	free_crypto(&crypto);

	kfree(new_conf);

 done:
@@ -2081,7 +2084,6 @@ int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info) 
	tconn->int_dig_vv = crypto.int_dig_vv;

	tconn->cram_hmac_tfm = crypto.cram_hmac_tfm;

	tconn->integrity_tfm = crypto.integrity_tfm;

	tconn->peer_integrity_tfm = crypto.peer_integrity_tfm;

	tconn->csums_tfm = crypto.csums_tfm;

	tconn->verify_tfm = crypto.verify_tfm;

drivers/block/drbd/drbd_receiver.c

+26 −28
Original line number Diff line number Diff line
@@ -1384,10 +1384,9 @@ read_in_block(struct drbd_conf *mdev, u64 id, sector_t sector, 
	void *dig_vv = mdev->tconn->int_dig_vv;

	unsigned long *data;



	dgs = (mdev->tconn->agreed_pro_version >= 87 && mdev->tconn->peer_integrity_tfm) ?

		crypto_hash_digestsize(mdev->tconn->peer_integrity_tfm) : 0;



	if (dgs) {

	dgs = 0;

	if (mdev->tconn->peer_integrity_tfm) {

		dgs = crypto_hash_digestsize(mdev->tconn->peer_integrity_tfm);

		/*

		 * FIXME: Receive the incoming digest into the receive buffer

		 *	  here, together with its struct p_data?
@@ -1395,9 +1394,8 @@ read_in_block(struct drbd_conf *mdev, u64 id, sector_t sector, 
		err = drbd_recv_all_warn(mdev->tconn, dig_in, dgs);

		if (err)

			return NULL;

	}



		data_size -= dgs;

	}



	if (!expect(data_size != 0))

		return NULL;
@@ -1491,16 +1489,14 @@ static int recv_dless_read(struct drbd_conf *mdev, struct drbd_request *req, 
	void *dig_in = mdev->tconn->int_dig_in;

	void *dig_vv = mdev->tconn->int_dig_vv;



	dgs = (mdev->tconn->agreed_pro_version >= 87 && mdev->tconn->peer_integrity_tfm) ?

		crypto_hash_digestsize(mdev->tconn->peer_integrity_tfm) : 0;



	if (dgs) {

	dgs = 0;

	if (mdev->tconn->peer_integrity_tfm) {

		dgs = crypto_hash_digestsize(mdev->tconn->peer_integrity_tfm);

		err = drbd_recv_all_warn(mdev->tconn, dig_in, dgs);

		if (err)

			return err;

	}



		data_size -= dgs;

	}



	/* optimistically update recv_cnt.  if receiving fails below,

	 * we disconnect anyways, and counters will be reset. */
@@ -2997,7 +2993,6 @@ static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi) 
	struct p_protocol *p = pi->data;

	int p_proto, p_after_sb_0p, p_after_sb_1p, p_after_sb_2p;

	int p_want_lose, p_two_primaries, cf;

	char p_integrity_alg[SHARED_SECRET_MAX] = "";

	struct net_conf *nc;



	p_proto		= be32_to_cpu(p->protocol);
@@ -3009,15 +3004,30 @@ static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi) 
	p_want_lose = cf & CF_WANT_LOSE;



	if (tconn->agreed_pro_version >= 87) {

		char integrity_alg[SHARED_SECRET_MAX];

		struct crypto_hash *tfm = NULL;

		int err;



		if (pi->size > sizeof(p_integrity_alg))

		if (pi->size > sizeof(integrity_alg))

			return -EIO;

		err = drbd_recv_all(tconn, p_integrity_alg, pi->size);

		err = drbd_recv_all(tconn, integrity_alg, pi->size);

		if (err)

			return err;

		integrity_alg[SHARED_SECRET_MAX-1] = 0;



		if (integrity_alg[0]) {

			tfm = crypto_alloc_hash(integrity_alg, 0, CRYPTO_ALG_ASYNC);

			if (!tfm) {

				conn_err(tconn, "peer data-integrity-alg %s not supported\n",

					 integrity_alg);

				goto disconnect;

			}

			conn_info(tconn, "peer data-integrity-alg: %s\n", integrity_alg);

		}



		p_integrity_alg[SHARED_SECRET_MAX-1] = 0;

		if (tconn->peer_integrity_tfm)

			crypto_free_hash(tconn->peer_integrity_tfm);

		tconn->peer_integrity_tfm = tfm;

	}



	clear_bit(CONN_DRY_RUN, &tconn->flags);
@@ -3058,20 +3068,8 @@ static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi) 
		goto disconnect_rcu_unlock;

	}



	if (tconn->agreed_pro_version >= 87) {

		if (strcmp(p_integrity_alg, nc->integrity_alg)) {

			conn_err(tconn, "incompatible setting of the data-integrity-alg\n");

			goto disconnect;

		}

	}



	rcu_read_unlock();



	if (tconn->agreed_pro_version >= 87) {

		conn_info(tconn, "data-integrity-alg: %s\n",

			  nc->integrity_alg[0] ? nc->integrity_alg : (unsigned char *)"<not-used>");

	}



	return 0;



disconnect_rcu_unlock: