[ovs-dev,4/4] ovn-ctl: Ability to upgrade databases.

diff --git a/ovn/utilities/ovn-ctl b/ovn/utilities/ovn-ctl
index 9f16021..69d4db8 100755
--- a/ovn/utilities/ovn-ctl
+++ b/ovn/utilities/ovn-ctl
@@ -30,31 +30,31 @@  done
 ## start ##
 ## ----- ##
 
-check_ovn_dbs () {
-    if test ! -e "$DB_NB_FILE"; then
-        create_db "$DB_NB_FILE" "$DB_NB_SCHEMA"
-    fi
-
-    if test ! -e "$DB_SB_FILE"; then
-        create_db "$DB_SB_FILE" "$DB_SB_SCHEMA"
-    fi
-
-    running_ovn_dbs=$(ovs-appctl -t ovsdb-server ovsdb-server/list-dbs | grep OVN | wc -l)
-    if [ "$running_ovn_dbs" != "2" ] ; then
-        ovs-appctl -t ovsdb-server ovsdb-server/add-db $DB_NB_FILE
-        ovs-appctl -t ovsdb-server ovsdb-server/add-db $DB_SB_FILE
-        running_ovn_dbs=$(ovs-appctl -t ovsdb-server ovsdb-server/list-dbs | grep OVN | wc -l)
-        if [ "$running_ovn_dbs" != "2" ] ; then
-            echo >&2 "$0: Failed to add OVN dbs to ovsdb-server"
-            exit 1
-        fi
-    fi
+upgrade_ovn_dbs () {
+    ovn_dbs=$(ovs-appctl -t ovsdb-server ovsdb-server/list-dbs 2>/dev/null)
+    for db in $ovn_dbs; do
+        case $db in
+            OVN_Northbound)
+                action "Removing $db from ovsdb-server" \
+                    ovs-appctl -t ovsdb-server ovsdb-server/remove-db $db
+                upgrade_db "$DB_NB_FILE" "$DB_NB_SCHEMA" || exit 1
+                ;;
+            OVN_Southbound)
+                action "Removing $db from ovsdb-server" \
+                    ovs-appctl -t ovsdb-server ovsdb-server/remove-db $db
+                upgrade_db "$DB_SB_FILE" "$DB_SB_SCHEMA" || exit 1
+        esac
+    done
+    for db in $DB_NB_FILE $DB_SB_FILE; do
+        action "Adding $db to ovsdb-server" \
+            ovs-appctl -t ovsdb-server ovsdb-server/add-db $db || exit 1
+    done
 }
 
 start_northd () {
     # We expect ovn-northd to be co-located with ovsdb-server handling both the
     # OVN_Northbound and OVN_Southbound dbs.
-    check_ovn_dbs
+    upgrade_ovn_dbs
 
     set ovn-northd
     set "$@" -vconsole:emer -vsyslog:err -vfile:info
diff --git a/utilities/ovs-ctl.in b/utilities/ovs-ctl.in
index 322e420..0082bed 100755
--- a/utilities/ovs-ctl.in
+++ b/utilities/ovs-ctl.in
@@ -76,45 +76,6 @@  ovs_vsctl () {
     ovs-vsctl --no-wait "$@"
 }
 
-upgrade_db () {
-    schemaver=`ovsdb_tool schema-version "$DB_SCHEMA"`
-    if test ! -e "$DB_FILE"; then
-        log_warning_msg "$DB_FILE does not exist"
-        install -d -m 755 -o root -g root `dirname $DB_FILE`
-        create_db "$DB_FILE" "$DB_SCHEMA"
-    elif test X"`ovsdb_tool needs-conversion "$DB_FILE" "$DB_SCHEMA"`" != Xno; then
-        # Back up the old version.
-        version=`ovsdb_tool db-version "$DB_FILE"`
-        cksum=`ovsdb_tool db-cksum "$DB_FILE" | awk '{print $1}'`
-        backup=$DB_FILE.backup$version-$cksum
-        action "Backing up database to $backup" cp "$DB_FILE" "$backup" || return 1
-
-        # Compact database.  This is important if the old schema did not enable
-        # garbage collection (i.e. if it did not have any tables with "isRoot":
-        # true) but the new schema does.  In that situation the old database
-        # may contain a transaction that creates a record followed by a
-        # transaction that creates the first use of the record.  Replaying that
-        # series of transactions against the new database schema (as "convert"
-        # does) would cause the record to be dropped by the first transaction,
-        # then the second transaction would cause a referential integrity
-        # failure (for a strong reference).
-        #
-        # Errors might occur on an Open vSwitch downgrade if ovsdb-tool doesn't
-        # understand some feature of the schema used in the OVSDB version that
-        # we're downgrading from, so we don't give up on error.
-        action "Compacting database" ovsdb_tool compact "$DB_FILE"
-
-        # Upgrade or downgrade schema.
-        if action "Converting database schema" ovsdb_tool convert "$DB_FILE" "$DB_SCHEMA"; then
-            :
-        else
-            log_warning_msg "Schema conversion failed, using empty database instead"
-            rm -f "$DB_FILE"
-            create_db "$DB_FILE" "$DB_SCHEMA"
-        fi
-    fi
-}
-
 set_system_ids () {
     set ovs_vsctl set Open_vSwitch .
 
@@ -182,7 +143,7 @@  start_ovsdb () {
         log_success_msg "ovsdb-server is already running"
     else
         # Create initial database or upgrade database schema.
-        upgrade_db || return 1
+        upgrade_db $DB_FILE $DB_SCHEMA || return 1
 
         # Start ovsdb-server.
         set ovsdb-server "$DB_FILE"
diff --git a/utilities/ovs-lib.in b/utilities/ovs-lib.in
index ef3150a..91e5d48 100644
--- a/utilities/ovs-lib.in
+++ b/utilities/ovs-lib.in
@@ -335,3 +335,45 @@  create_db () {
     DB_SCHEMA="$2"
     action "Creating empty database $DB_FILE" ovsdb_tool create "$DB_FILE" "$DB_SCHEMA"
 }
+
+upgrade_db () {
+    DB_FILE="$1"
+    DB_SCHEMA="$2"
+
+    schemaver=`ovsdb_tool schema-version "$DB_SCHEMA"`
+    if test ! -e "$DB_FILE"; then
+        log_warning_msg "$DB_FILE does not exist"
+        install -d -m 755 -o root -g root `dirname $DB_FILE`
+        create_db "$DB_FILE" "$DB_SCHEMA"
+    elif test X"`ovsdb_tool needs-conversion "$DB_FILE" "$DB_SCHEMA"`" != Xno; then
+        # Back up the old version.
+        version=`ovsdb_tool db-version "$DB_FILE"`
+        cksum=`ovsdb_tool db-cksum "$DB_FILE" | awk '{print $1}'`
+        backup=$DB_FILE.backup$version-$cksum
+        action "Backing up database to $backup" cp "$DB_FILE" "$backup" || return 1
+
+        # Compact database.  This is important if the old schema did not enable
+        # garbage collection (i.e. if it did not have any tables with "isRoot":
+        # true) but the new schema does.  In that situation the old database
+        # may contain a transaction that creates a record followed by a
+        # transaction that creates the first use of the record.  Replaying that
+        # series of transactions against the new database schema (as "convert"
+        # does) would cause the record to be dropped by the first transaction,
+        # then the second transaction would cause a referential integrity
+        # failure (for a strong reference).
+        #
+        # Errors might occur on an Open vSwitch downgrade if ovsdb-tool doesn't
+        # understand some feature of the schema used in the OVSDB version that
+        # we're downgrading from, so we don't give up on error.
+        action "Compacting database" ovsdb_tool compact "$DB_FILE"
+
+        # Upgrade or downgrade schema.
+        if action "Converting database schema" ovsdb_tool convert "$DB_FILE" "$DB_SCHEMA"; then
+            :
+        else
+            log_warning_msg "Schema conversion failed, using empty database instead"
+            rm -f "$DB_FILE"
+			create_db "$DB_FILE" "$DB_SCHEMA"
+        fi
+    fi
+}