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: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index dc5824b..17c0cda 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1793,7 +1793,6 @@
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 @@
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 @@
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 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 @@
conn_reconfig_start(tconn);
+ mutex_lock(&tconn->data.mutex);
mutex_lock(&tconn->net_conf_update);
old_conf = tconn->net_conf;
@@ -1931,6 +1927,9 @@
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 @@
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 @@
fail:
mutex_unlock(&tconn->net_conf_update);
+ mutex_unlock(&tconn->data.mutex);
free_crypto(&crypto);
kfree(new_conf);
done:
@@ -2081,7 +2084,6 @@
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;