qemu-iotests: COW with many AIO requests on the same cluster

This one is a bit more interesting. The COW operation isn't performed
completely synchronously, and therefore dependencies must be handled
correctly when multiple requests write to the same unallocated cluster.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

tests/qemu-iotests/038

@@ -0,0 +1,133 @@
+#!/bin/bash
+#
+# Test COW from backing files with AIO
+#
+# Copyright (C) 2012 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=kwolf@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+
+_cleanup()
+{
+	_cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2 qed
+_supported_proto generic
+_supported_os Linux
+
+CLUSTER_SIZE=2M
+size=128M
+
+echo
+echo "== creating backing file for COW tests =="
+
+_make_test_img $size
+
+function backing_io()
+{
+    local offset=$1
+    local sectors=$2
+    local op=$3
+    local pattern=0
+    local cur_sec=0
+
+    for i in $(seq 0 $((sectors - 1))); do
+        cur_sec=$((offset / 65536 + i))
+        pattern=$(( ( (cur_sec % 128) + (cur_sec / 128)) % 128 ))
+
+        echo "$op -P $pattern $((cur_sec * 64))k 64k"
+    done
+}
+
+backing_io 0 256 write | $QEMU_IO $TEST_IMG | _filter_qemu_io
+
+mv $TEST_IMG $TEST_IMG.base
+
+_make_test_img -b $TEST_IMG.base 6G
+
+echo
+echo "== Some concurrent requests touching the same cluster =="
+
+function overlay_io()
+{
+    # Start with a request touching two clusters
+    echo aio_write -P 0x80 2020k 80k
+
+    # Then add some requests all over the place
+    for i in $(seq 0 15; seq 17 31; seq 33 47); do
+        echo aio_write -P $((0x81 + i)) $((i * 128))k 64k
+    done
+
+    # Then backwards overwriting part of them
+    for i in $( (seq 0 15; seq 17 31; seq 33 47) | tac); do
+        echo aio_write -P $((0x81 + i)) $((i * 128 + 32))k 64k
+    done
+
+    # And finally crossing the next cluster boundary
+    echo aio_write -P 0x90 4080k 80k
+}
+
+overlay_io | $QEMU_IO $TEST_IMG | _filter_qemu_io |\
+	sed -e 's/bytes at offset [0-9]*/bytes at offset XXX/g'
+
+echo
+echo "== Verify image content =="
+
+function verify_io()
+{
+    echo read -P 31 2016k 4k
+    echo read -P 0x80 2020k 80k
+    echo read -P 32 2100k 12k
+    echo read -P 33 2112k 64k
+
+    echo read -P 63 4064k 16k
+    echo read -P 0x90 4080k 80k
+    echo read -P 65 4160k 64k
+
+    for i in $(seq 0 15; seq 17 31; seq 33 47); do
+        echo read -P $((0x81 + i)) $((i * 128))k 96k
+    done
+
+    for i in $(seq 0 14; seq 16 30; seq 32 47); do
+        local cur_sec=$(( i * 2 + 1 ))
+        local pattern=$(( ( (cur_sec % 128) + (cur_sec / 128)) % 128 ))
+
+        echo read -P $pattern $((i * 128 + 96))k 32k
+    done
+}
+
+verify_io | $QEMU_IO $TEST_IMG | _filter_qemu_io
+
+_check_test_img
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0