tests: allow qemu-iotests to be run against nbd backend

To do this, we start a qemu-nbd process at _make_test_img and kill
it in _cleanup_test_img. $TEST_IMG is changed to point at the TCP
server. We also remove the checks for existence of binaries from
common.config - they're duplicated in common, and we can make the
qemu-nbd check conditional on $IMGPROTO being "nbd" if we do it there.

Signed-off-by: Nick Thomas <nick@bytemark.co.uk>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/common

@@ -136,6 +136,7 @@ check options
     -vmdk               test vmdk
     -rbd                test rbd
     -sheepdog           test sheepdog
+    -nbd                test nbd
     -xdiff		graphical mode diff
     -nocache		use O_DIRECT on backing file
     -misalign		misalign memory allocations
@@ -197,12 +198,14 @@ testlist options
 	    IMGPROTO=rbd
 	    xpand=false
 	    ;;
-
 	-sheepdog)
 	    IMGPROTO=sheepdog
 	    xpand=false
 	    ;;
-
+	-nbd)
+	    IMGPROTO=nbd
+	    xpand=false
+	    ;;
 	-nocache)
 	    QEMU_IO_OPTIONS="$QEMU_IO_OPTIONS --nocache"
 	    xpand=false
@@ -350,7 +353,11 @@ fi
 
 [ "$QEMU" = "" ] && _fatal "qemu not found"
 [ "$QEMU_IMG" = "" ] && _fatal "qemu-img not found"
-[ "$QEMU_IO" = "" ] && _fatal "qemu-img not found"
+[ "$QEMU_IO" = "" ] && _fatal "qemu-io not found"
+
+if [ "$IMGPROTO" = "nbd" ] ; then
+    [ "$QEMU_NBD" = "" ] && _fatal "qemu-nbd not found"
+fi
 
 if $valgrind; then
     export REAL_QEMU_IO="$QEMU_IO_PROG"

tests/qemu-iotests/common.config

@@ -90,21 +90,23 @@ export PS_ALL_FLAGS="-ef"
 if [ -z "$QEMU_PROG" ]; then
     export QEMU_PROG="`set_prog_path qemu`"
 fi
-[ "$QEMU_PROG" = "" ] && _fatal "qemu not found"
 
 if [ -z "$QEMU_IMG_PROG" ]; then
     export QEMU_IMG_PROG="`set_prog_path qemu-img`"
 fi
-[ "$QEMU_IMG_PROG" = "" ] && _fatal "qemu-img not found"
 
 if [ -z "$QEMU_IO_PROG" ]; then
     export QEMU_IO_PROG="`set_prog_path qemu-io`"
 fi
-[ "$QEMU_IO_PROG" = "" ] && _fatal "qemu-io not found"
+
+if [ -z "$QEMU_NBD_PROG" ]; then
+    export QEMU_NBD_PROG="`set_prog_path qemu-nbd`"
+fi
 
 export QEMU=$QEMU_PROG
-export QEMU_IMG=$QEMU_IMG_PROG 
+export QEMU_IMG=$QEMU_IMG_PROG
 export QEMU_IO="$QEMU_IO_PROG $QEMU_IO_OPTIONS"
+export QEMU_NBD=$QEMU_NBD_PROG
 
 [ -f /etc/qemu-iotest.config ]       && . /etc/qemu-iotest.config
 

tests/qemu-iotests/common.rc

@@ -49,6 +49,9 @@ umask 022
 
 if [ "$IMGPROTO" = "file" ]; then
     TEST_IMG=$TEST_DIR/t.$IMGFMT
+elif [ "$IMGPROTO" = "nbd" ]; then
+    TEST_IMG_FILE=$TEST_DIR/t.$IMGFMT
+    TEST_IMG="nbd:127.0.0.1:10810"
 else
     TEST_IMG=$IMGPROTO:$TEST_DIR/t.$IMGFMT
 fi
@@ -86,6 +89,13 @@ _make_test_img()
     local extra_img_options=""
     local image_size=$*
     local optstr=""
+    local img_name=""
+
+    if [ -n "$TEST_IMG_FILE" ]; then
+        img_name=$TEST_IMG_FILE
+    else
+        img_name=$TEST_IMG
+    fi
 
     if [ -n "$IMGOPTS" ]; then
         optstr=$(_optstr_add "$optstr" "$IMGOPTS")
@@ -104,7 +114,7 @@ _make_test_img()
     fi
 
     # XXX(hch): have global image options?
-    $QEMU_IMG create -f $IMGFMT $extra_img_options $TEST_IMG $image_size | \
+    $QEMU_IMG create -f $IMGFMT $extra_img_options $img_name $image_size | \
         sed -e "s#$IMGPROTO:$TEST_DIR#TEST_DIR#g" \
             -e "s#$TEST_DIR#TEST_DIR#g" \
             -e "s#$IMGFMT#IMGFMT#g" \
@@ -115,12 +125,23 @@ _make_test_img()
             -e "s# compat6=\\(on\\|off\\)##g" \
             -e "s# static=\\(on\\|off\\)##g" \
             -e "s# lazy_refcounts=\\(on\\|off\\)##g"
+
+    # Start an NBD server on the image file, which is what we'll be talking to
+    if [ $IMGPROTO = "nbd" ]; then
+        eval "$QEMU_NBD -v -t -b 127.0.0.1 -p 10810  $TEST_IMG_FILE &"
+        QEMU_NBD_PID=$!
+        sleep 1 # FIXME: qemu-nbd needs to be listening before we continue
+    fi
 }
 
 _cleanup_test_img()
 {
     case "$IMGPROTO" in
 
+        nbd)
+            kill $QEMU_NBD_PID
+            rm -f $TEST_IMG_FILE
+            ;;
         file)
             rm -f $TEST_DIR/t.$IMGFMT
             rm -f $TEST_DIR/t.$IMGFMT.orig