diff mbox series

[RFC,5/9] selftests: block_seek_hole: add dm-zero test

Message ID 20240328203910.2370087-6-stefanha@redhat.com (mailing list archive)
State Deferred, archived
Delegated to: Mike Snitzer
Headers show
Series block: add llseek(SEEK_HOLE/SEEK_DATA) support | expand

Commit Message

Stefan Hajnoczi March 28, 2024, 8:39 p.m. UTC 
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 .../selftests/block_seek_hole/Makefile        |  2 +-
 .../testing/selftests/block_seek_hole/config  |  2 ++
 .../selftests/block_seek_hole/dm_zero.sh      | 31 +++++++++++++++++++
 3 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100755 tools/testing/selftests/block_seek_hole/dm_zero.sh

Comments

Eric Blake March 28, 2024, 10:19 p.m. UTC | #1 
On Thu, Mar 28, 2024 at 04:39:06PM -0400, Stefan Hajnoczi wrote:
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  .../selftests/block_seek_hole/Makefile        |  2 +-
>  .../testing/selftests/block_seek_hole/config  |  2 ++
>  .../selftests/block_seek_hole/dm_zero.sh      | 31 +++++++++++++++++++
>  3 files changed, 34 insertions(+), 1 deletion(-)
>  create mode 100755 tools/testing/selftests/block_seek_hole/dm_zero.sh
> 

> +++ b/tools/testing/selftests/block_seek_hole/dm_zero.sh
> @@ -0,0 +1,31 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0-only
> +#
> +# dm_zero.sh
> +#
> +# Test that dm-zero reports data because it does not have a custom
> +# SEEK_HOLE/SEEK_DATA implementation.

Why not?  Wouldn't it make more sense to have dm-zero report the
entire device as a hole (that is, an in-range SEEK_HOLE always returns
the same offset, while an in-range SEEK_DATA returns the device size)?
Stefan Hajnoczi March 28, 2024, 10:32 p.m. UTC | #2 
On Thu, Mar 28, 2024 at 05:19:26PM -0500, Eric Blake wrote:
> On Thu, Mar 28, 2024 at 04:39:06PM -0400, Stefan Hajnoczi wrote:
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  .../selftests/block_seek_hole/Makefile        |  2 +-
> >  .../testing/selftests/block_seek_hole/config  |  2 ++
> >  .../selftests/block_seek_hole/dm_zero.sh      | 31 +++++++++++++++++++
> >  3 files changed, 34 insertions(+), 1 deletion(-)
> >  create mode 100755 tools/testing/selftests/block_seek_hole/dm_zero.sh
> > 
> 
> > +++ b/tools/testing/selftests/block_seek_hole/dm_zero.sh
> > @@ -0,0 +1,31 @@
> > +#!/bin/sh
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +#
> > +# dm_zero.sh
> > +#
> > +# Test that dm-zero reports data because it does not have a custom
> > +# SEEK_HOLE/SEEK_DATA implementation.
> 
> Why not?  Wouldn't it make more sense to have dm-zero report the
> entire device as a hole (that is, an in-range SEEK_HOLE always returns
> the same offset, while an in-range SEEK_DATA returns the device size)?

Yes, dm-zero could report a hole. I just added this test to verify that
targets that do not implement seek_hole_data() work and the dm-zero
target was convenient for testing.

Stefan

> 
> -- 
> Eric Blake, Principal Software Engineer
> Red Hat, Inc.
> Virtualization:  qemu.org | libguestfs.org
>
diff mbox series

Patch

diff --git a/tools/testing/selftests/block_seek_hole/Makefile b/tools/testing/selftests/block_seek_hole/Makefile
index 3f4bbd52db29f..1bd9e748b2acc 100644
--- a/tools/testing/selftests/block_seek_hole/Makefile
+++ b/tools/testing/selftests/block_seek_hole/Makefile
@@ -3,7 +3,7 @@  PY3 = $(shell which python3 2>/dev/null)
 
 ifneq ($(PY3),)
 
-TEST_PROGS := test.py
+TEST_PROGS := test.py dm_zero.sh
 
 include ../lib.mk
 
diff --git a/tools/testing/selftests/block_seek_hole/config b/tools/testing/selftests/block_seek_hole/config
index 72437e0c0fc1c..bfd59f1d98769 100644
--- a/tools/testing/selftests/block_seek_hole/config
+++ b/tools/testing/selftests/block_seek_hole/config
@@ -1 +1,3 @@ 
 CONFIG_BLK_DEV_LOOP=m
+CONFIG_BLK_DEV_DM=m
+CONFIG_DM_ZERO=m
diff --git a/tools/testing/selftests/block_seek_hole/dm_zero.sh b/tools/testing/selftests/block_seek_hole/dm_zero.sh
new file mode 100755
index 0000000000000..20836a566fcc8
--- /dev/null
+++ b/tools/testing/selftests/block_seek_hole/dm_zero.sh
@@ -0,0 +1,31 @@ 
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# dm_zero.sh
+#
+# Test that dm-zero reports data because it does not have a custom
+# SEEK_HOLE/SEEK_DATA implementation.
+
+set -e
+
+dev_name=test-$$
+size=$((1024 * 1024 * 1024 / 512)) # 1 GB
+
+cleanup() {
+	dmsetup remove $dev_name
+}
+trap cleanup EXIT
+
+dmsetup create $dev_name --table "0 $size zero"
+
+output=$(./map_holes.py /dev/mapper/$dev_name)
+expected='TYPE START END SIZE
+DATA 0 1073741824 1073741824'
+
+if [ "$output" != "$expected" ]; then
+	echo 'FAIL expected:'
+	echo "$expected"
+	echo 'Does not match device output:'
+	echo "$output"
+	exit 1
+fi