tests: Add coverage for recent block geometry fixes

Use blkdebug's new geometry constraints to emulate setups that
have needed past regression fixes: write zeroes asserting
when running through a loopback block device with max-transfer
smaller than cluster size, and discard rounding away portions
of requests not aligned to preferred boundaries.  Also, add
coverage that the block layer is honoring max transfer limits.

For now, a single iotest performs all actions, with the idea
that we can add future blkdebug constraint test cases in the
same file; but it can be split into multiple iotests if we find
reason to run one portion of the test in more setups than what
are possible in the other.

For reference, the final portion of the test (checking whether
discard passes as much as possible to the lowest layers of the
stack) works as follows:

qemu-io: discard 30M at 80000001, passed to blkdebug
  blkdebug: discard 511 bytes at 80000001, -ENOTSUP (smaller than
blkdebug's 512 align)
  blkdebug: discard 14371328 bytes at 80000512, passed to qcow2
    qcow2: discard 739840 bytes at 80000512, -ENOTSUP (smaller than
qcow2's 1M align)
    qcow2: discard 13M bytes at 77M, succeeds
  blkdebug: discard 15M bytes at 90M, passed to qcow2
    qcow2: discard 15M bytes at 90M, succeeds
  blkdebug: discard 1356800 bytes at 105M, passed to qcow2
    qcow2: discard 1M at 105M, succeeds
    qcow2: discard 308224 bytes at 106M, -ENOTSUP (smaller than qcow2's
1M align)
  blkdebug: discard 1 byte at 111457280, -ENOTSUP (smaller than
blkdebug's 512 align)

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170429191419.30051-10-eblake@redhat.com
[mreitz: For cooperation with image locking, add -r to the qemu-io
         invocation which verifies the image content]
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 114 insertions, 0 deletions

diff --git a/tests/qemu-iotests/177 b/tests/qemu-iotests/177
new file mode 100755
index 0000000000..2005c174f2
--- /dev/null
+++ b/tests/qemu-iotests/177
@@ -0,0 +1,114 @@
+#!/bin/bash
+#
+# Test corner cases with unusual block geometries
+#
+# Copyright (C) 2016-2017 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=eblake@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+status=1	# failure is the default!
+
+_cleanup()
+{
+	_cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2
+_supported_proto file
+
+CLUSTER_SIZE=1M
+size=128M
+options=driver=blkdebug,image.driver=qcow2
+
+echo
+echo "== setting up files =="
+
+TEST_IMG="$TEST_IMG.base" _make_test_img $size
+$QEMU_IO -c "write -P 11 0 $size" "$TEST_IMG.base" | _filter_qemu_io
+_make_test_img -b "$TEST_IMG.base"
+$QEMU_IO -c "write -P 22 0 $size" "$TEST_IMG" | _filter_qemu_io
+
+# Limited to 64k max-transfer
+echo
+echo "== constrained alignment and max-transfer =="
+limits=align=4k,max-transfer=64k
+$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
+         -c "write -P 33 1000 128k" -c "read -P 33 1000 128k" | _filter_qemu_io
+
+echo
+echo "== write zero with constrained max-transfer =="
+limits=align=512,max-transfer=64k,opt-write-zero=$CLUSTER_SIZE
+$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
+         -c "write -z 8003584 2093056" | _filter_qemu_io
+
+# non-power-of-2 write-zero/discard alignments
+echo
+echo "== non-power-of-2 write zeroes limits =="
+
+limits=align=512,opt-write-zero=15M,max-write-zero=15M,opt-discard=15M,max-discard=15M
+$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
+         -c "write -z 32M 32M" | _filter_qemu_io
+
+echo
+echo "== non-power-of-2 discard limits =="
+
+limits=align=512,opt-write-zero=15M,max-write-zero=15M,opt-discard=15M,max-discard=15M
+$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
+         -c "discard 80000001 30M" | _filter_qemu_io
+
+echo
+echo "== verify image content =="
+
+function verify_io()
+{
+    if ($QEMU_IMG info -f "$IMGFMT" "$TEST_IMG" |
+	    grep "compat: 0.10" > /dev/null); then
+        # For v2 images, discarded clusters are read from the backing file
+        discarded=11
+    else
+        # Discarded clusters are zeroed for v3 or later
+        discarded=0
+    fi
+
+    echo read -P 22 0 1000
+    echo read -P 33 1000 128k
+    echo read -P 22 132072 7871512
+    echo read -P 0 8003584 2093056
+    echo read -P 22 10096640 23457792
+    echo read -P 0 32M 32M
+    echo read -P 22 64M 13M
+    echo read -P $discarded 77M 29M
+    echo read -P 22 106M 22M
+}
+
+verify_io | $QEMU_IO -r "$TEST_IMG" | _filter_qemu_io
+
+_check_test_img
+
+# success, all done
+echo "*** done"
+status=0