diff mbox

[v2,20/21] qemu-iotests: Test cache mode option inheritance

Message ID 1448294400-476-21-git-send-email-kwolf@redhat.com
State New
Headers show

Commit Message

Kevin Wolf Nov. 23, 2015, 3:59 p.m. UTC 
This is doing a more complete test on setting cache modes both while
opening an image (i.e. in a -drive command line) and in reopen
situations. It checks that reopen can specify options for child nodes
and that cache modes are correctly inherited from parent nodes where
they are not specified.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/qemu-iotests/142     | 354 ++++++++++++++++++++
 tests/qemu-iotests/142.out | 788 +++++++++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/group   |   1 +
 3 files changed, 1143 insertions(+)
 create mode 100755 tests/qemu-iotests/142
 create mode 100644 tests/qemu-iotests/142.out

Comments

Max Reitz Nov. 27, 2015, 9:12 p.m. UTC | #1 
On 23.11.2015 16:59, Kevin Wolf wrote:
> This is doing a more complete test on setting cache modes both while
> opening an image (i.e. in a -drive command line) and in reopen
> situations. It checks that reopen can specify options for child nodes
> and that cache modes are correctly inherited from parent nodes where
> they are not specified.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  tests/qemu-iotests/142     | 354 ++++++++++++++++++++
>  tests/qemu-iotests/142.out | 788 +++++++++++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/group   |   1 +
>  3 files changed, 1143 insertions(+)
>  create mode 100755 tests/qemu-iotests/142
>  create mode 100644 tests/qemu-iotests/142.out

Comments below, to make it short: With %s/bs->backing_hd/bs->backing/
and a comment about why you commented 'out | grep "Cache"':

Reviewed-by: Max Reitz <mreitz@redhat.com>

> diff --git a/tests/qemu-iotests/142 b/tests/qemu-iotests/142
> new file mode 100755
> index 0000000..58daf26
> --- /dev/null
> +++ b/tests/qemu-iotests/142
> @@ -0,0 +1,354 @@
> +#!/bin/bash
> +#
> +# Test for configuring cache modes of arbitrary nodes (requires O_DIRECT)
> +#
> +# Copyright (C) 2015 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
> +    rm -f $TEST_IMG.snap
> +}
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +# get standard environment, filters and checks
> +. ./common.rc
> +. ./common.filter
> +
> +_supported_fmt qcow2
> +_supported_proto file
> +_supported_os Linux
> +
> +# We test all cache modes anyway, but O_DIRECT needs to be supported
> +_default_cache_mode none
> +_supported_cache_modes none directsync
> +
> +function do_run_qemu()
> +{
> +    echo Testing: "$@"
> +    (
> +        if ! test -t 0; then
> +            while read cmd; do
> +                echo $cmd
> +            done
> +        fi
> +        echo quit
> +    ) | $QEMU -nographic -monitor stdio -nodefaults "$@"
> +    echo
> +}
> +
> +function run_qemu()
> +{
> +    do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qemu
> +}
> +
> +size=128M
> +
> +TEST_IMG="$TEST_IMG.base" _make_test_img $size
> +TEST_IMG="$TEST_IMG.snap" _make_test_img $size
> +_make_test_img -b "$TEST_IMG.base" $size
> +
> +echo
> +echo === Simple test for all cache modes ===
> +echo
> +
> +run_qemu -drive file="$TEST_IMG",cache=none
> +run_qemu -drive file="$TEST_IMG",cache=directsync
> +run_qemu -drive file="$TEST_IMG",cache=writeback
> +run_qemu -drive file="$TEST_IMG",cache=writethrough
> +run_qemu -drive file="$TEST_IMG",cache=unsafe
> +run_qemu -drive file="$TEST_IMG",cache=invalid_value
> +
> +echo
> +echo === Check inheritance of cache modes ===
> +echo
> +
> +files="if=none,file=$TEST_IMG,backing.file.filename=$TEST_IMG.base"
> +ids="node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file"
> +
> +function check_cache_all()
> +{
> +    # cache.direct is supposed to be inherited by both bs->file and
> +    # bs->backing_hd

%s/bs->backing_hd/bs->backing/g

> +
> +    echo -e "cache.direct=on on none0"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",cache.direct=on | grep "Cache"
> +    echo -e "\ncache.direct=on on file"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",file.cache.direct=on | grep "Cache"
> +    echo -e "\ncache.direct=on on backing"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.cache.direct=on | grep "Cache"
> +    echo -e "\ncache.direct=on on backing-file"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.file.cache.direct=on | grep "Cache"
> +
> +    # cache.writeback is supposed to be inherited by bs->backing_hd; bs->file
> +    # always gets cache.writeback=on

I don't know whether having the backing file inherit cache.writeback
makes any sense, but I guess it's the default behavior and overriding it
wouldn't make any sense either.

> +    echo -e "\n\ncache.writeback=off on none0"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",cache.writeback=off | grep "Cache"
> +    echo -e "\ncache.writeback=off on file"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",file.cache.writeback=off | grep "Cache"
> +    echo -e "\ncache.writeback=off on backing"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.cache.writeback=off | grep "Cache"
> +    echo -e "\ncache.writeback=off on backing-file"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.file.cache.writeback=off | grep "Cache"
> +
> +    # cache.no-flush is supposed to be inherited by both bs->file and bs->backing_hd
> +
> +    echo -e "\n\ncache.no-flush=on on none0"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",cache.no-flush=on | grep "Cache"
> +    echo -e "\ncache.no-flush=on on file"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",file.cache.no-flush=on | grep "Cache"
> +    echo -e "\ncache.no-flush=on on backing"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.cache.no-flush=on | grep "Cache"
> +    echo -e "\ncache.no-flush=on on backing-file"
> +    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.file.cache.no-flush=on | grep "Cache"
> +}

[...]

> +echo
> +echo "--- Change cache mode in parent, child has explicit option in JSON ---"
> +echo
> +
> +# This checks that children with options explicitly set by the json:
> +# pseudo-protocol don't inherit these options from their parents.
> +#
> +# Yes, blkdebug::json:... is criminal, but I can't see another way to have a
> +# BDS initialised with the json: pseudo-protocol, but still have it inherit
> +# options from its parent node.

I'd suggest a json:{} backing file name (stored in the overlay, and thus
implicitly opened). This is what we originally intended to have json:{}
for, after all. ;-)

> +hmp_cmds="qemu-io none0 \"reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=on\"
> +info block image
> +info block blkdebug
> +info block file"
> +
> +echo "$hmp_cmds" | run_qemu -drive if=none,file="blkdebug::json:{\"filename\":\"$TEST_IMG\",,\"cache\":{\"writeback\":false,,\"direct\":false}}",node-name=image,file.node-name=blkdebug,file.image.node-name=file #| grep "Cache"

Why is the grep commented out? If it wasn't, I wouldn't have had to fix
my patch fix script (see below)...

[...]

> diff --git a/tests/qemu-iotests/142.out b/tests/qemu-iotests/142.out
> new file mode 100644
> index 0000000..c141fb8
> --- /dev/null
> +++ b/tests/qemu-iotests/142.out
> @@ -0,0 +1,788 @@

[...]

> +
> +--- Change cache mode in parent, child has explicit option in JSON ---
> +
> +Testing: -drive if=none,file=blkdebug::json:{"filename":"TEST_DIR/t.qcow2",,"cache":{"writeback":false,,"direct":false}},node-name=image,file.node-name=blkdebug,file.image.node-name=file
> +QEMU X.Y.Z monitor - type 'help' for more information
> +(qemu) qqeqemqemuqemu-qemu-iqemu-ioqemu-io qemu-io nqemu-io noqemu-io nonqemu-io noneqemu-io none0qemu-io none0 qemu-io none0 "qemu-io none0 "rqemu-io none0 "reqemu-io none0 "reoqemu-io none0 "reopqemu-io none0 "reopeqemu-io none0 "reopen!
>  qemu-io none0 "reopen qemu-io none0 "reopen -qemu-io none0 "reopen -oqemu-io none0 "reopen -o qemu-io none0 "reopen -o cqemu-io none0 "reopen -o caqemu-io none0 "reopen -o cacqemu-io none0 "reopen -o cachqemu-io none0 "reopen -o cacheqemu-io none0 "reop!
>  en -o cache.qemu-io none0 "reopen -o cache.wqemu-io none0 "reopen -o cache.wrqemu-io none0 "reopen -o cache.wriqemu-io none0 "reopen -o cache.writqemu-io none0 "reopen -o cache.writeqemu-io none0 "reopen -o cache.writebqemu-io none0 "reopen -o cache.writeba
[
>  D!
>  [Dqemu-io none0 "reopen -o cache.writebacqemu-io none0 "reopen -o cache.writebackqemu-io none0 "reopen -o cache.writeback=qemu-io none0 "reopen -o cache.writeback=oqemu-io none0 "reopen -o cache.writeback=ofqemu-io none0 "reopen -o cache.writeback=off[!
>  Dqemu-io none0 "reopen -o cache.writeback=off,qemu-io none0 "reopen -o cache.writeback=off,cqemu-io none0 "reopen -o cache.writeback=off,caqemu-io none0 "reopen -o cache.writeback=off,cacqemu-io none0 "reopen -o cache.writeback=off,cach
[
>  Dqemu-io none0 "reopen -o cac!
>  he.writeback=off,cacheqemu-io none0 "reopen -o cache.writeback=off,cache.qemu-io none0 "reopen -o cache.writeback=off,cache.dqemu-io none0 "reopen -o cache.writeback=off,cache.diqemu-io none0 "reopen -o cache.writeback=off,cache.dir!
>  qemu-io none0 "reopen -o cache.writeback=off,cache.direqemu-io none0 "reopen -o cache.writeback=off,cache.direcqemu-io none0 "reopen -o cache.writeback=off,cache.directqemu-io none0 "reopen -o cache.writeback=off,cache.direct=qemu-io none0 "reopen -o cache.writeback=
o
>  ff,cache.direct=o!
>  qemu-io none0 "reopen -o cache.writeback=off,cache.direct=onqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,qemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,ca!
>  [Dqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cacqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cachqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cacheqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cac
h
>  e.!
>  qemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.nqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.noqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-qemu-io!
>   none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-fqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-fluqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flus[
D
>  [!
>  Dqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flushqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=qemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=o!
>  qemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=onqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=on"

Congratulations, you win the "Patch has a line so long it breaks my
large-patch-fixer.rb" prize. Or, alternatively, the "Patch has a line so
long with so many special characters it breaks git's per-line character
counter" (I think).

Some split lines don't end in an exclamation mark (probably because they
are so long), so my script doesn't know whether to merge them or not,
and others have an exclamation mark at the end (and need to be merged)
but have actually less than 78 characters.

(Apparently, git sometimes generates lines with 998 characters and then
cannot insert a ! anymore (because CRLF alone takes 2 bytes). The lines
ending in ! have 990 characters. So I guess it's a bug in git. And the
fact that it's always lines following a 998 character line that are
actually too short to be merged makes it look like git didn't even
notice it split a line there, so somehow its counting seems to be off.)

((Based on the 998-character information, I was now able to amend my
large-patch-fixer.rb so it is able to reconstruct this line.))

Max

> +(qemu) iininfinfoinfo info binfo blinfo bloinfo blocinfo blockinfo block info block iinfo block iminfo block imainfo block imaginfo block image
> +
> +image: blkdebug::TEST_DIR/t.qcow2 (qcow2)
> +    Cache mode:       writethrough, direct, ignore flushes
> +    Backing file:     TEST_DIR/t.qcow2.base (chain depth: 1)
> +(qemu) iininfinfoinfo info binfo blinfo bloinfo blocinfo blockinfo block info block binfo block blinfo block blkinfo block blkdinfo block blkdeinfo block blkdebinfo block blkdebuinfo block blkdebug
> +
> +blkdebug: blkdebug::TEST_DIR/t.qcow2 (blkdebug)
> +    Cache mode:       writeback, direct, ignore flushes
> +(qemu) iininfinfoinfo info binfo blinfo bloinfo blocinfo blockinfo block info block finfo block fiinfo block filinfo block file
> +
> +file: TEST_DIR/t.qcow2 (file)
> +    Cache mode:       writethrough, ignore flushes
> +(qemu) qququiquit
Kevin Wolf Nov. 30, 2015, 10:32 a.m. UTC | #2 
Am 27.11.2015 um 22:12 hat Max Reitz geschrieben:
> On 23.11.2015 16:59, Kevin Wolf wrote:
> > This is doing a more complete test on setting cache modes both while
> > opening an image (i.e. in a -drive command line) and in reopen
> > situations. It checks that reopen can specify options for child nodes
> > and that cache modes are correctly inherited from parent nodes where
> > they are not specified.
> > 
> > Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> > ---
> >  tests/qemu-iotests/142     | 354 ++++++++++++++++++++
> >  tests/qemu-iotests/142.out | 788 +++++++++++++++++++++++++++++++++++++++++++++
> >  tests/qemu-iotests/group   |   1 +
> >  3 files changed, 1143 insertions(+)
> >  create mode 100755 tests/qemu-iotests/142
> >  create mode 100644 tests/qemu-iotests/142.out
> 
> Comments below, to make it short: With %s/bs->backing_hd/bs->backing/
> and a comment about why you commented 'out | grep "Cache"':

Because I'm stupid. I'll fix that, thanks.

Kevin
diff mbox

Patch

diff --git a/tests/qemu-iotests/142 b/tests/qemu-iotests/142
new file mode 100755
index 0000000..58daf26
--- /dev/null
+++ b/tests/qemu-iotests/142
@@ -0,0 +1,354 @@ 
+#!/bin/bash
+#
+# Test for configuring cache modes of arbitrary nodes (requires O_DIRECT)
+#
+# Copyright (C) 2015 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
+    rm -f $TEST_IMG.snap
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+# We test all cache modes anyway, but O_DIRECT needs to be supported
+_default_cache_mode none
+_supported_cache_modes none directsync
+
+function do_run_qemu()
+{
+    echo Testing: "$@"
+    (
+        if ! test -t 0; then
+            while read cmd; do
+                echo $cmd
+            done
+        fi
+        echo quit
+    ) | $QEMU -nographic -monitor stdio -nodefaults "$@"
+    echo
+}
+
+function run_qemu()
+{
+    do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qemu
+}
+
+size=128M
+
+TEST_IMG="$TEST_IMG.base" _make_test_img $size
+TEST_IMG="$TEST_IMG.snap" _make_test_img $size
+_make_test_img -b "$TEST_IMG.base" $size
+
+echo
+echo === Simple test for all cache modes ===
+echo
+
+run_qemu -drive file="$TEST_IMG",cache=none
+run_qemu -drive file="$TEST_IMG",cache=directsync
+run_qemu -drive file="$TEST_IMG",cache=writeback
+run_qemu -drive file="$TEST_IMG",cache=writethrough
+run_qemu -drive file="$TEST_IMG",cache=unsafe
+run_qemu -drive file="$TEST_IMG",cache=invalid_value
+
+echo
+echo === Check inheritance of cache modes ===
+echo
+
+files="if=none,file=$TEST_IMG,backing.file.filename=$TEST_IMG.base"
+ids="node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file"
+
+function check_cache_all()
+{
+    # cache.direct is supposed to be inherited by both bs->file and
+    # bs->backing_hd
+
+    echo -e "cache.direct=on on none0"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",cache.direct=on | grep "Cache"
+    echo -e "\ncache.direct=on on file"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",file.cache.direct=on | grep "Cache"
+    echo -e "\ncache.direct=on on backing"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.cache.direct=on | grep "Cache"
+    echo -e "\ncache.direct=on on backing-file"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.file.cache.direct=on | grep "Cache"
+
+    # cache.writeback is supposed to be inherited by bs->backing_hd; bs->file
+    # always gets cache.writeback=on
+
+    echo -e "\n\ncache.writeback=off on none0"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",cache.writeback=off | grep "Cache"
+    echo -e "\ncache.writeback=off on file"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",file.cache.writeback=off | grep "Cache"
+    echo -e "\ncache.writeback=off on backing"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.cache.writeback=off | grep "Cache"
+    echo -e "\ncache.writeback=off on backing-file"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.file.cache.writeback=off | grep "Cache"
+
+    # cache.no-flush is supposed to be inherited by both bs->file and bs->backing_hd
+
+    echo -e "\n\ncache.no-flush=on on none0"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",cache.no-flush=on | grep "Cache"
+    echo -e "\ncache.no-flush=on on file"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",file.cache.no-flush=on | grep "Cache"
+    echo -e "\ncache.no-flush=on on backing"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.cache.no-flush=on | grep "Cache"
+    echo -e "\ncache.no-flush=on on backing-file"
+    echo "$hmp_cmds" | run_qemu -drive "$files","$ids",backing.file.cache.no-flush=on | grep "Cache"
+}
+
+echo
+echo "--- Configure cache modes on the command line ---"
+echo
+
+# First check the inherited cache mode after opening the image.
+
+hmp_cmds="info block image
+info block file
+info block backing
+info block backing-file"
+
+check_cache_all
+
+echo
+echo "--- Cache modes after reopen (live snapshot) ---"
+echo
+
+# Then trigger a reopen and check that the cache modes are still the same.
+
+hmp_cmds="snapshot_blkdev -n none0 $TEST_IMG.snap $IMGFMT
+info block
+info block image
+info block file
+info block backing
+info block backing-file"
+
+check_cache_all
+
+echo
+echo "--- Change cache modes with reopen (qemu-io command, flags) ---"
+echo
+
+# This one actually changes the cache mode with the reopen. For this test, the
+# new cache mode is specified in the flags, not as an option.
+
+hmp_cmds='qemu-io none0 "reopen -c none"
+info block image
+info block file
+info block backing
+info block backing-file'
+
+check_cache_all
+
+echo
+echo "--- Change cache modes with reopen (qemu-io command, options) ---"
+echo
+
+# This one actually changes the cache mode with the reopen. For this test, the
+# new cache mode is specified as an option, not in the flags.
+
+hmp_cmds='qemu-io none0 "reopen -o cache.direct=on"
+info block image
+info block file
+info block backing
+info block backing-file'
+
+check_cache_all
+
+echo
+echo "--- Change cache modes after snapshot ---"
+echo
+
+# This checks that the original image doesn't inherit from the snapshot
+
+hmp_cmds="snapshot_blkdev -n none0 $TEST_IMG.snap $IMGFMT
+qemu-io none0 \"reopen -c none\"
+info block none0
+info block image
+info block file
+info block backing
+info block backing-file"
+
+check_cache_all
+
+echo
+echo "--- Change cache mode in parent, child has explicit option in JSON ---"
+echo
+
+# This checks that children with options explicitly set by the json:
+# pseudo-protocol don't inherit these options from their parents.
+#
+# Yes, blkdebug::json:... is criminal, but I can't see another way to have a
+# BDS initialised with the json: pseudo-protocol, but still have it inherit
+# options from its parent node.
+
+hmp_cmds="qemu-io none0 \"reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=on\"
+info block image
+info block blkdebug
+info block file"
+
+echo "$hmp_cmds" | run_qemu -drive if=none,file="blkdebug::json:{\"filename\":\"$TEST_IMG\",,\"cache\":{\"writeback\":false,,\"direct\":false}}",node-name=image,file.node-name=blkdebug,file.image.node-name=file #| grep "Cache"
+
+echo
+echo "=== Check that referenced BDSes don't inherit ==="
+echo
+
+drv_bkfile="if=none,driver=file,filename=$TEST_IMG.base,node-name=backing-file"
+drv_bk="if=none,file=json:{'driver':'$IMGFMT',,'file':'backing-file',,'node-name':'backing'}"
+drv_file="if=none,driver=file,filename=$TEST_IMG,node-name=file"
+drv_img="if=none,id=blk,file=json:{'driver':'$IMGFMT',,'file':'file',,'backing':'backing',,'node-name':'image'}"
+
+function check_cache_all_separate()
+{
+    # Check cache.direct
+
+    echo -e "cache.direct=on on blk"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile" -drive "$drv_bk" -drive "$drv_file" -drive "$drv_img",cache.direct=on | grep "Cache"
+    echo -e "\ncache.direct=on on file"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile" -drive "$drv_bk" -drive "$drv_file",cache.direct=on -drive "$drv_img" | grep "Cache"
+    echo -e "\ncache.direct=on on backing"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile" -drive "$drv_bk",cache.direct=on -drive "$drv_file" -drive "$drv_img" | grep "Cache"
+    echo -e "\ncache.direct=on on backing-file"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile",cache.direct=on -drive "$drv_bk" -drive "$drv_file" -drive "$drv_img" | grep "Cache"
+
+    # Check cache.writeback
+
+    echo -e "\n\ncache.writeback=off on blk"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile" -drive "$drv_bk" -drive "$drv_file" -drive "$drv_img",cache.writeback=off | grep "Cache"
+    echo -e "\ncache.writeback=off on file"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile" -drive "$drv_bk" -drive "$drv_file",cache.writeback=off -drive "$drv_img" | grep "Cache"
+    echo -e "\ncache.writeback=off on backing"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile" -drive "$drv_bk",cache.writeback=off -drive "$drv_file" -drive "$drv_img" | grep "Cache"
+    echo -e "\ncache.writeback=off on backing-file"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile",cache.writeback=off -drive "$drv_bk" -drive "$drv_file" -drive "$drv_img" | grep "Cache"
+
+    # Check cache.no-flush
+
+    echo -e "\n\ncache.no-flush=on on blk"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile" -drive "$drv_bk" -drive "$drv_file" -drive "$drv_img",cache.no-flush=on | grep "Cache"
+    echo -e "\ncache.no-flush=on on file"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile" -drive "$drv_bk" -drive "$drv_file",cache.no-flush=on -drive "$drv_img" | grep "Cache"
+    echo -e "\ncache.no-flush=on on backing"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile" -drive "$drv_bk",cache.no-flush=on -drive "$drv_file" -drive "$drv_img" | grep "Cache"
+    echo -e "\ncache.no-flush=on on backing-file"
+    echo "$hmp_cmds" | run_qemu -drive "$drv_bkfile",cache.no-flush=on -drive "$drv_bk" -drive "$drv_file" -drive "$drv_img" | grep "Cache"
+}
+
+echo
+echo "--- Configure cache modes on the command line ---"
+echo
+
+# First check the inherited cache mode after opening the image.
+
+hmp_cmds="info block image
+info block file
+info block backing
+info block backing-file"
+
+check_cache_all_separate
+
+echo
+echo "--- Cache modes after reopen (live snapshot) ---"
+echo
+
+# Then trigger a reopen and check that the cache modes are still the same.
+
+hmp_cmds="snapshot_blkdev -n blk $TEST_IMG.snap $IMGFMT
+info block blk
+info block image
+info block file
+info block backing
+info block backing-file"
+
+check_cache_all_separate
+
+echo
+echo "--- Change cache modes with reopen (qemu-io command, flags) ---"
+echo
+
+# This one actually changes the cache mode with the reopen. For this test, the
+# new cache mode is specified as flags, not as option.
+
+hmp_cmds='qemu-io blk "reopen -c none"
+info block image
+info block file
+info block backing
+info block backing-file'
+
+check_cache_all_separate
+
+
+echo
+echo "=== Reopening children instead of the root ==="
+echo
+
+files="if=none,file=$TEST_IMG,backing.file.filename=$TEST_IMG.base"
+ids="node-name=image,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file"
+
+echo
+echo "--- Basic reopen ---"
+echo
+
+hmp_cmds='qemu-io none0 "reopen -o backing.cache.direct=on"
+info block image
+info block file
+info block backing
+info block backing-file'
+
+check_cache_all
+
+echo
+echo "--- Change cache mode after reopening child ---"
+echo
+
+# This checks that children with options explicitly set with reopen don't
+# inherit these options from their parents any more
+
+# TODO Implement node-name support for 'qemu-io' HMP command for -c
+# Can use only -o to access child node options for now
+
+hmp_cmds="qemu-io none0 \"reopen -o file.cache.writeback=off,file.cache.direct=off,file.cache.no-flush=off\"
+qemu-io none0 \"reopen -o backing.file.cache.writeback=on,backing.file.cache.direct=off,backing.file.cache.no-flush=on\"
+qemu-io none0 \"reopen -c none\"
+info block image
+info block file
+info block backing
+info block backing-file"
+
+echo "$hmp_cmds" | run_qemu -drive "$files","$ids" | grep "Cache"
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/142.out b/tests/qemu-iotests/142.out
new file mode 100644
index 0000000..c141fb8
--- /dev/null
+++ b/tests/qemu-iotests/142.out
@@ -0,0 +1,788 @@ 
+QA output created by 142
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=134217728
+Formatting 'TEST_DIR/t.IMGFMT.snap', fmt=IMGFMT size=134217728
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 backing_file=TEST_DIR/t.IMGFMT.base
+
+=== Simple test for all cache modes ===
+
+Testing: -drive file=TEST_DIR/t.qcow2,cache=none
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) qququiquit
+
+Testing: -drive file=TEST_DIR/t.qcow2,cache=directsync
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) qququiquit
+
+Testing: -drive file=TEST_DIR/t.qcow2,cache=writeback
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) qququiquit
+
+Testing: -drive file=TEST_DIR/t.qcow2,cache=writethrough
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) qququiquit
+
+Testing: -drive file=TEST_DIR/t.qcow2,cache=unsafe
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) qququiquit
+
+Testing: -drive file=TEST_DIR/t.qcow2,cache=invalid_value
+QEMU_PROG: -drive file=TEST_DIR/t.qcow2,cache=invalid_value: invalid cache option
+
+
+=== Check inheritance of cache modes ===
+
+
+--- Configure cache modes on the command line ---
+
+cache.direct=on on none0
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on file
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.direct=on on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+
+
+cache.writeback=off on none0
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+
+cache.writeback=off on file
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.writeback=off on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+
+cache.writeback=off on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+
+
+cache.no-flush=on on none0
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+
+cache.no-flush=on on file
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.no-flush=on on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+
+cache.no-flush=on on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+
+--- Cache modes after reopen (live snapshot) ---
+
+cache.direct=on on none0
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.direct=on on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+
+
+cache.writeback=off on none0
+    Cache mode:       writethrough
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+
+cache.writeback=off on file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.writeback=off on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+
+cache.writeback=off on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+
+
+cache.no-flush=on on none0
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+
+cache.no-flush=on on file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.no-flush=on on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+
+cache.no-flush=on on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+
+--- Change cache modes with reopen (qemu-io command, flags) ---
+
+cache.direct=on on none0
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+
+cache.writeback=off on none0
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.writeback=off on file
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.writeback=off on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough, direct
+    Cache mode:       writeback, direct
+
+cache.writeback=off on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough, direct
+
+
+cache.no-flush=on on none0
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.no-flush=on on file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct, ignore flushes
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.no-flush=on on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct, ignore flushes
+    Cache mode:       writeback, direct, ignore flushes
+
+cache.no-flush=on on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct, ignore flushes
+
+--- Change cache modes with reopen (qemu-io command, options) ---
+
+cache.direct=on on none0
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+
+cache.writeback=off on none0
+    Cache mode:       writethrough, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough, direct
+    Cache mode:       writeback, direct
+
+cache.writeback=off on file
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.writeback=off on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough, direct
+    Cache mode:       writeback, direct
+
+cache.writeback=off on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough, direct
+
+
+cache.no-flush=on on none0
+    Cache mode:       writeback, direct, ignore flushes
+    Cache mode:       writeback, direct, ignore flushes
+    Cache mode:       writeback, direct, ignore flushes
+    Cache mode:       writeback, direct, ignore flushes
+
+cache.no-flush=on on file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct, ignore flushes
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.no-flush=on on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct, ignore flushes
+    Cache mode:       writeback, direct, ignore flushes
+
+cache.no-flush=on on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct, ignore flushes
+
+--- Change cache modes after snapshot ---
+
+cache.direct=on on none0
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.direct=on on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+
+
+cache.writeback=off on none0
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+
+cache.writeback=off on file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.writeback=off on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+
+cache.writeback=off on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+
+
+cache.no-flush=on on none0
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+
+cache.no-flush=on on file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.no-flush=on on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+
+cache.no-flush=on on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+
+--- Change cache mode in parent, child has explicit option in JSON ---
+
+Testing: -drive if=none,file=blkdebug::json:{"filename":"TEST_DIR/t.qcow2",,"cache":{"writeback":false,,"direct":false}},node-name=image,file.node-name=blkdebug,file.image.node-name=file
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) qqeqemqemuqemu-qemu-iqemu-ioqemu-io qemu-io nqemu-io noqemu-io nonqemu-io noneqemu-io none0qemu-io none0 qemu-io none0 "qemu-io none0 "rqemu-io none0 "reqemu-io none0 "reoqemu-io none0 "reopqemu-io none0 "reopeqemu-io none0 "reopen!
 qemu-io none0 "reopen qemu-io none0 "reopen -qemu-io none0 "reopen -oqemu-io none0 "reopen -o qemu-io none0 "reopen -o cqemu-io none0 "reopen -o caqemu-io none0 "reopen -o cacqemu-io none0 "reopen -o cachqemu-io none0 "reopen -o cacheqemu-io none0 "reop!
 en -o cache.qemu-io none0 "reopen -o cache.wqemu-io none0 "reopen -o cache.wrqemu-io none0 "reopen -o cache.wriqemu-io none0 "reopen -o cache.writqemu-io none0 "reopen -o cache.writeqemu-io none0 "reopen -o cache.writebqemu-io none0 "reopen -o cache.writeba[
 D!
 [Dqemu-io none0 "reopen -o cache.writebacqemu-io none0 "reopen -o cache.writebackqemu-io none0 "reopen -o cache.writeback=qemu-io none0 "reopen -o cache.writeback=oqemu-io none0 "reopen -o cache.writeback=ofqemu-io none0 "reopen -o cache.writeback=off[!
 Dqemu-io none0 "reopen -o cache.writeback=off,qemu-io none0 "reopen -o cache.writeback=off,cqemu-io none0 "reopen -o cache.writeback=off,caqemu-io none0 "reopen -o cache.writeback=off,cacqemu-io none0 "reopen -o cache.writeback=off,cach[
 Dqemu-io none0 "reopen -o cac!
 he.writeback=off,cacheqemu-io none0 "reopen -o cache.writeback=off,cache.qemu-io none0 "reopen -o cache.writeback=off,cache.dqemu-io none0 "reopen -o cache.writeback=off,cache.diqemu-io none0 "reopen -o cache.writeback=off,cache.dir!
 qemu-io none0 "reopen -o cache.writeback=off,cache.direqemu-io none0 "reopen -o cache.writeback=off,cache.direcqemu-io none0 "reopen -o cache.writeback=off,cache.directqemu-io none0 "reopen -o cache.writeback=off,cache.direct=qemu-io none0 "reopen -o cache.writeback=o
 ff,cache.direct=o!
 qemu-io none0 "reopen -o cache.writeback=off,cache.direct=onqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,qemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,ca!
 [Dqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cacqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cachqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cacheqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cach
 e.!
 qemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.nqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.noqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-qemu-io!
  none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-fqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-fluqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flus
 [!
 Dqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flushqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=qemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=o!
 qemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=onqemu-io none0 "reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=on"
+(qemu) iininfinfoinfo info binfo blinfo bloinfo blocinfo blockinfo block info block iinfo block iminfo block imainfo block imaginfo block image
+
+image: blkdebug::TEST_DIR/t.qcow2 (qcow2)
+    Cache mode:       writethrough, direct, ignore flushes
+    Backing file:     TEST_DIR/t.qcow2.base (chain depth: 1)
+(qemu) iininfinfoinfo info binfo blinfo bloinfo blocinfo blockinfo block info block binfo block blinfo block blkinfo block blkdinfo block blkdeinfo block blkdebinfo block blkdebuinfo block blkdebug
+
+blkdebug: blkdebug::TEST_DIR/t.qcow2 (blkdebug)
+    Cache mode:       writeback, direct, ignore flushes
+(qemu) iininfinfoinfo info binfo blinfo bloinfo blocinfo blockinfo block info block finfo block fiinfo block filinfo block file
+
+file: TEST_DIR/t.qcow2 (file)
+    Cache mode:       writethrough, ignore flushes
+(qemu) qququiquit
+
+
+=== Check that referenced BDSes don't inherit ===
+
+
+--- Configure cache modes on the command line ---
+
+cache.direct=on on blk
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.direct=on on file
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.direct=on on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+
+cache.direct=on on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+
+
+cache.writeback=off on blk
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.writeback=off on file
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.writeback=off on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+
+cache.writeback=off on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+
+
+cache.no-flush=on on blk
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.no-flush=on on file
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.no-flush=on on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+
+cache.no-flush=on on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+
+--- Cache modes after reopen (live snapshot) ---
+
+cache.direct=on on blk
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.direct=on on file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.direct=on on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+
+cache.direct=on on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+
+
+cache.writeback=off on blk
+    Cache mode:       writethrough
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.writeback=off on file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.writeback=off on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+
+cache.writeback=off on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+
+
+cache.no-flush=on on blk
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.no-flush=on on file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.no-flush=on on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+
+cache.no-flush=on on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+
+--- Change cache modes with reopen (qemu-io command, flags) ---
+
+cache.direct=on on blk
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.direct=on on file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.direct=on on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+
+cache.direct=on on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+
+
+cache.writeback=off on blk
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.writeback=off on file
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.writeback=off on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback
+
+cache.writeback=off on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough
+
+
+cache.no-flush=on on blk
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.no-flush=on on file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+    Cache mode:       writeback
+
+cache.no-flush=on on backing
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback
+
+cache.no-flush=on on backing-file
+    Cache mode:       writeback, direct
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+
+=== Reopening children instead of the root ===
+
+
+--- Basic reopen ---
+
+cache.direct=on on none0
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on file
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.direct=on on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+
+cache.writeback=off on none0
+    Cache mode:       writethrough
+    Cache mode:       writeback
+    Cache mode:       writethrough, direct
+    Cache mode:       writeback, direct
+
+cache.writeback=off on file
+    Cache mode:       writeback
+    Cache mode:       writethrough
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.writeback=off on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writethrough, direct
+    Cache mode:       writeback, direct
+
+cache.writeback=off on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough, direct
+
+
+cache.no-flush=on on none0
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, direct, ignore flushes
+    Cache mode:       writeback, direct, ignore flushes
+
+cache.no-flush=on on file
+    Cache mode:       writeback
+    Cache mode:       writeback, ignore flushes
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct
+
+cache.no-flush=on on backing
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct, ignore flushes
+    Cache mode:       writeback, direct, ignore flushes
+
+cache.no-flush=on on backing-file
+    Cache mode:       writeback
+    Cache mode:       writeback
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, direct, ignore flushes
+
+--- Change cache mode after reopening child ---
+
+    Cache mode:       writeback, direct
+    Cache mode:       writethrough
+    Cache mode:       writeback, direct
+    Cache mode:       writeback, ignore flushes
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 5a08808..ed6ce09 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -140,3 +140,4 @@ 
 137 rw auto
 138 rw auto quick
 139 rw auto quick
+142 auto