Revert part of c/s 19349: fixes qcow for HVM guests

3 files changed, 95 insertions, 0 deletions

diff --git a/tools/hotplug/Linux/Makefile b/tools/hotplug/Linux/Makefile
index 0fb56aa79a..36f3ee0242 100644
--- a/tools/hotplug/Linux/Makefile
+++ b/tools/hotplug/Linux/Makefile
@@ -12,6 +12,7 @@ XEN_SCRIPTS += network-route vif-route
 XEN_SCRIPTS += network-nat vif-nat
 XEN_SCRIPTS += block
 XEN_SCRIPTS += block-enbd block-nbd
+XEN_SCRIPTS += blktap
 XEN_SCRIPTS += vtpm vtpm-delete
 XEN_SCRIPTS += xen-hotplug-cleanup
 XEN_SCRIPTS += external-device-migrate
diff --git a/tools/hotplug/Linux/blktap b/tools/hotplug/Linux/blktap
new file mode 100644
index 0000000000..01a0f6c6da
--- /dev/null
+++ b/tools/hotplug/Linux/blktap
@@ -0,0 +1,93 @@
+#!/bin/bash
+
+# Copyright (c) 2005, XenSource Ltd.
+
+dir=$(dirname "$0")
+. "$dir/xen-hotplug-common.sh"
+. "$dir/block-common.sh"
+
+findCommand "$@"
+
+##
+# check_blktap_sharing file mode
+#
+# Perform the sharing check for the given blktap and mode.
+#
+check_blktap_sharing()
+{
+    local file="$1"
+    local mode="$2"
+
+    local base_path="$XENBUS_BASE_PATH/$XENBUS_TYPE"
+    for dom in $(xenstore-list "$base_path")
+    do
+        for dev in $(xenstore-list "$base_path/$dom")
+        do
+            params=$(xenstore_read "$base_path/$dom/$dev/params" | cut -d: -f2)
+            if [ "$file" = "$params" ]
+            then
+
+                if [ "$mode" = 'w' ]
+                then
+                    if ! same_vm "$dom" 
+                    then
+                        echo 'guest'
+                        return
+                    fi
+                else 
+                    local m=$(xenstore_read "$base_path/$dom/$dev/mode")
+                    m=$(canonicalise_mode "$m")
+
+                    if [ "$m" = 'w' ] 
+                    then
+                        if ! same_vm "$dom"
+                        then
+                            echo 'guest'
+                            return
+                        fi
+                    fi
+                fi
+            fi
+        done
+    done
+
+    echo 'ok'
+}
+
+
+t=$(xenstore_read_default "$XENBUS_PATH/type" 'MISSING')
+if [ -n "$t" ]
+then
+    p=$(xenstore_read "$XENBUS_PATH/params")
+    # if we have a ':', chew from head including :
+    if echo $p | grep -q \:
+    then
+        p=${p#*:}
+    fi
+fi
+# some versions of readlink cannot be passed a regular file
+if [ -L "$p" ]; then
+    file=$(readlink -f "$p") || fatal "$p link does not exist."
+else
+    file="$p"
+fi
+
+if [ "$command" = 'add' ]
+then
+    [ -e "$file" ] || { fatal $file does not exist; }
+
+    FRONTEND_ID=$(xenstore_read "$XENBUS_PATH/frontend-id")
+    FRONTEND_UUID=$(xenstore_read "/local/domain/$FRONTEND_ID/vm")
+    mode=$(xenstore_read "$XENBUS_PATH/mode")
+    mode=$(canonicalise_mode "$mode")
+
+    if [ "$mode" != '!' ] 
+    then
+        result=$(check_blktap_sharing "$file" "$mode")
+        [ "$result" = 'ok' ] || ebusy "$file already in use by other domain"
+    fi
+
+    success
+fi
+
+exit 0
diff --git a/tools/hotplug/Linux/xen-backend.rules b/tools/hotplug/Linux/xen-backend.rules
index 69048faa6f..3b1c1759da 100644
--- a/tools/hotplug/Linux/xen-backend.rules
+++ b/tools/hotplug/Linux/xen-backend.rules
@@ -1,3 +1,4 @@
+SUBSYSTEM=="xen-backend", KERNEL=="tap*", RUN+="/etc/xen/scripts/blktap $env{ACTION}"
 SUBSYSTEM=="xen-backend", KERNEL=="vbd*", RUN+="/etc/xen/scripts/block $env{ACTION}"
 SUBSYSTEM=="xen-backend", KERNEL=="vtpm*", RUN+="/etc/xen/scripts/vtpm $env{ACTION}"
 SUBSYSTEM=="xen-backend", KERNEL=="vif*", ACTION=="online", RUN+="$env{script} online"