[Xen-changelog] [xen-unstable] Add sharing-check for blktap

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Date 1187341372 -3600
# Node ID bd8647a7b992c01743e89b7d0d6b258774acee53
# Parent  ac7a8c9d620262fd8d193130e3e6f7b2d3be95db
Add sharing-check for blktap

Signed-off-by: Takanori Kasai <kasai.takanori@xxxxxxxxxxxxxx>
Signed-off-by: Hirofumi Tsujimura <tsujimura.hirof@xxxxxxxxxxxxxx>
---
 tools/examples/blktap          |   57 +++++++++++++++++++++++++++++++++++++++++
 tools/examples/block           |   42 ------------------------------
 tools/examples/block-common.sh |   43 ++++++++++++++++++++++++++++++
 3 files changed, 100 insertions(+), 42 deletions(-)

diff -r ac7a8c9d6202 -r bd8647a7b992 tools/examples/blktap
--- a/tools/examples/blktap     Fri Aug 17 10:01:40 2007 +0100
+++ b/tools/examples/blktap     Fri Aug 17 10:02:52 2007 +0100
@@ -7,6 +7,57 @@ dir=$(dirname "$0")
 . "$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 "$dom"
+                        then
+                            echo 'guest'
+                            return
+                        fi
+                    fi
+                fi
+            fi
+        done
+    done
+
+    echo 'ok'
+}
+
+FRONTEND_ID=$(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")
 
 t=$(xenstore_read_default "$XENBUS_PATH/type" 'MISSING')
 if [ -n "$t" ]
@@ -20,6 +71,12 @@ fi
 fi
 file=$(readlink -f "$p") || ebusy "$p does not exist."
 
+if [ "$mode" != '!' ] 
+then
+    result=$(check_blktap_sharing "$file" "$mode")
+    [ "$result" = 'ok' ] || ebusy "$file already in use by other domain"
+fi
+
 if [ "$command" = 'add' ]
 then
     [ -e "$file" ] || { ebusy $file does not exist; }
diff -r ac7a8c9d6202 -r bd8647a7b992 tools/examples/block
--- a/tools/examples/block      Fri Aug 17 10:01:40 2007 +0100
+++ b/tools/examples/block      Fri Aug 17 10:02:52 2007 +0100
@@ -14,32 +14,6 @@ expand_dev() {
     ;;
   esac
   echo -n $dev
-}
-
-
-##
-# canonicalise_mode mode
-#
-# Takes the given mode, which may be r, w, ro, rw, w!, or rw!, or variations
-# thereof, and canonicalises them to one of
-#
-#   'r': perform checks for a new read-only mount;
-#   'w': perform checks for a read-write mount; or
-#   '!': perform no checks at all.
-#
-canonicalise_mode()
-{
-  local mode="$1"
-
-  if ! expr index "$mode" 'w' >/dev/null
-  then
-    echo 'r'
-  elif ! expr index "$mode" '!' >/dev/null
-  then
-    echo 'w'
-  else
-    echo '!'
-  fi
 }
 
 
@@ -123,22 +97,6 @@ check_sharing()
   done
 
   echo 'ok'
-}
-
-
-same_vm()
-{
-  local otherdom="$1"
-  # Note that othervm can be MISSING here, because Xend will be racing with
-  # the hotplug scripts -- the entries in /local/domain can be removed by
-  # Xend before the hotplug scripts have removed the entry in
-  # /local/domain/0/backend/.  In this case, we want to pretend that the
-  # VM is the same as FRONTEND_UUID, because that way the 'sharing' will be
-  # allowed.
-  local othervm=$(xenstore_read_default "/local/domain/$otherdom/vm"         \
-                  "$FRONTEND_UUID")
-
-  [ "$FRONTEND_UUID" = "$othervm" ]
 }
 
 
diff -r ac7a8c9d6202 -r bd8647a7b992 tools/examples/block-common.sh
--- a/tools/examples/block-common.sh    Fri Aug 17 10:01:40 2007 +0100
+++ b/tools/examples/block-common.sh    Fri Aug 17 10:02:52 2007 +0100
@@ -71,3 +71,46 @@ write_dev() {
 
   success
 }
+
+
+##
+# canonicalise_mode mode
+#
+# Takes the given mode, which may be r, w, ro, rw, w!, or rw!, or variations
+# thereof, and canonicalises them to one of
+#
+#   'r': perform checks for a new read-only mount;
+#   'w': perform checks for a read-write mount; or
+#   '!': perform no checks at all.
+#
+canonicalise_mode()
+{
+  local mode="$1"
+
+  if ! expr index "$mode" 'w' >/dev/null
+  then
+    echo 'r'
+  elif ! expr index "$mode" '!' >/dev/null
+  then
+    echo 'w'
+  else
+    echo '!'
+  fi
+}
+
+
+same_vm()
+{
+  local otherdom="$1"
+  # Note that othervm can be MISSING here, because Xend will be racing with
+  # the hotplug scripts -- the entries in /local/domain can be removed by
+  # Xend before the hotplug scripts have removed the entry in
+  # /local/domain/0/backend/.  In this case, we want to pretend that the
+  # VM is the same as FRONTEND_UUID, because that way the 'sharing' will be
+  # allowed.
+  local othervm=$(xenstore_read_default "/local/domain/$otherdom/vm"         \
+                  "$FRONTEND_UUID")
+
+  [ "$FRONTEND_UUID" = "$othervm" ]
+}
+

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