4185 New hash algorithm support

@@ -21,10 +21,11 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright 2013 Saso Kiselkov. All rights reserved.
  */
 
 /*
  * SPA: Storage Pool Allocator
  *

@@ -2408,10 +2409,29 @@
                 spa_activate(spa, orig_mode);
 
                 return (spa_load(spa, state, SPA_IMPORT_EXISTING, B_TRUE));
         }
 
+        /* Grab the secret checksum salt from the MOS. */
+        if (spa_dir_prop(spa, DMU_POOL_CHECKSUM_SALT,
+            &spa->spa_cksum_salt_obj) == 0) {
+                if (zap_lookup(spa->spa_meta_objset, spa->spa_cksum_salt_obj,
+                    DMU_POOL_CHECKSUM_SALT, 1,
+                    sizeof (spa->spa_cksum_salt.zcs_bytes),
+                    spa->spa_cksum_salt.zcs_bytes) != 0) {
+                        /*
+                         * MOS format is broken, the salt object is there but
+                         * is missing the actual salt value.
+                         */
+                        return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+                }
+        } else {
+                /* Generate a new salt for subsequent use */
+                (void) random_get_pseudo_bytes(spa->spa_cksum_salt.zcs_bytes,
+                    sizeof (spa->spa_cksum_salt.zcs_bytes));
+        }
+
         if (spa_dir_prop(spa, DMU_POOL_SYNC_BPOBJ, &obj) != 0)
                 return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
         error = bpobj_open(&spa->spa_deferred_bpobj, spa->spa_meta_objset, obj);
         if (error != 0)
                 return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));

@@ -3554,10 +3574,19 @@
          */
         if (version >= SPA_VERSION_ZPOOL_HISTORY)
                 spa_history_create_obj(spa, tx);
 
         /*
+         * Generate some random noise for salted checksums to operate on. As
+         * soon as a salted checksum is used for the first time we will
+         * generate the persistent MOS object to hold the salt (see
+         * spa_activate_salted_cksum).
+         */
+        (void) random_get_pseudo_bytes(spa->spa_cksum_salt.zcs_bytes,
+            sizeof (spa->spa_cksum_salt.zcs_bytes));
+
+        /*
          * Set pool properties.
          */
         spa->spa_bootfs = zpool_prop_default_numeric(ZPOOL_PROP_BOOTFS);
         spa->spa_delegation = zpool_prop_default_numeric(ZPOOL_PROP_DELEGATION);
         spa->spa_failmode = zpool_prop_default_numeric(ZPOOL_PROP_FAILUREMODE);