[PATCH v3 13/19] selftests: ublk: add utility to get block device metadata size

Caleb Sander Mateos posted 19 patches 1 month ago
There is a newer version of this series
[PATCH v3 13/19] selftests: ublk: add utility to get block device metadata size
Posted by Caleb Sander Mateos 1 month ago
Some block device integrity parameters are available in sysfs, but
others are only accessible using the FS_IOC_GETLBMD_CAP ioctl. Add a
metadata_size utility program to print out the logical block metadata
size, PI offset, and PI size within the metadata. Example output:
$ metadata_size /dev/ublkb0
metadata_size: 64
pi_offset: 56
pi_tuple_size: 8

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
---
 tools/testing/selftests/ublk/Makefile        |  4 +--
 tools/testing/selftests/ublk/metadata_size.c | 36 ++++++++++++++++++++
 2 files changed, 38 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/ublk/metadata_size.c

diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile
index 06ba6fde098d..41f776bb86a6 100644
--- a/tools/testing/selftests/ublk/Makefile
+++ b/tools/testing/selftests/ublk/Makefile
@@ -47,14 +47,14 @@ TEST_PROGS += test_stress_03.sh
 TEST_PROGS += test_stress_04.sh
 TEST_PROGS += test_stress_05.sh
 TEST_PROGS += test_stress_06.sh
 TEST_PROGS += test_stress_07.sh
 
-TEST_GEN_PROGS_EXTENDED = kublk
+TEST_GEN_PROGS_EXTENDED = kublk metadata_size
 
 LOCAL_HDRS += $(wildcard *.h)
 include ../lib.mk
 
-$(TEST_GEN_PROGS_EXTENDED): $(wildcard *.c)
+$(OUTPUT)/kublk: common.c fault_inject.c file_backed.c kublk.c null.c stripe.c
 
 check:
 	shellcheck -x -f gcc *.sh
diff --git a/tools/testing/selftests/ublk/metadata_size.c b/tools/testing/selftests/ublk/metadata_size.c
new file mode 100644
index 000000000000..76ecddf04d25
--- /dev/null
+++ b/tools/testing/selftests/ublk/metadata_size.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+
+int main(int argc, char **argv)
+{
+	struct logical_block_metadata_cap cap = {};
+	const char *filename;
+	int fd;
+	int result;
+
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s BLOCK_DEVICE\n", argv[0]);
+		return 1;
+	}
+
+	filename = argv[1];
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		perror(filename);
+		return 1;
+	}
+
+	result = ioctl(fd, FS_IOC_GETLBMD_CAP, &cap);
+	if (result < 0) {
+		perror("ioctl");
+		return 1;
+	}
+
+	printf("metadata_size: %u\n", cap.lbmd_size);
+	printf("pi_offset: %u\n", cap.lbmd_pi_offset);
+	printf("pi_tuple_size: %u\n", cap.lbmd_pi_size);
+	return 0;
+}
-- 
2.45.2
Re: [PATCH v3 13/19] selftests: ublk: add utility to get block device metadata size
Posted by Ming Lei 1 month ago
On Mon, Jan 05, 2026 at 05:57:45PM -0700, Caleb Sander Mateos wrote:
> Some block device integrity parameters are available in sysfs, but
> others are only accessible using the FS_IOC_GETLBMD_CAP ioctl. Add a
> metadata_size utility program to print out the logical block metadata
> size, PI offset, and PI size within the metadata. Example output:
> $ metadata_size /dev/ublkb0
> metadata_size: 64
> pi_offset: 56
> pi_tuple_size: 8
> 
> Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
> ---
>  tools/testing/selftests/ublk/Makefile        |  4 +--
>  tools/testing/selftests/ublk/metadata_size.c | 36 ++++++++++++++++++++
>  2 files changed, 38 insertions(+), 2 deletions(-)
>  create mode 100644 tools/testing/selftests/ublk/metadata_size.c
> 
> diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile
> index 06ba6fde098d..41f776bb86a6 100644
> --- a/tools/testing/selftests/ublk/Makefile
> +++ b/tools/testing/selftests/ublk/Makefile
> @@ -47,14 +47,14 @@ TEST_PROGS += test_stress_03.sh
>  TEST_PROGS += test_stress_04.sh
>  TEST_PROGS += test_stress_05.sh
>  TEST_PROGS += test_stress_06.sh
>  TEST_PROGS += test_stress_07.sh
>  
> -TEST_GEN_PROGS_EXTENDED = kublk
> +TEST_GEN_PROGS_EXTENDED = kublk metadata_size
>  
>  LOCAL_HDRS += $(wildcard *.h)
>  include ../lib.mk
>  
> -$(TEST_GEN_PROGS_EXTENDED): $(wildcard *.c)
> +$(OUTPUT)/kublk: common.c fault_inject.c file_backed.c kublk.c null.c stripe.c

I feel wildcard is pretty handy, can we avoid to kill it? Such as:

STANDALONE_UTILS := metadata_size.c
KUBLK_SRCS := $(filter-out $(STANDALONE_UTILS),$(wildcard *.c))


Thanks, 
Ming
Re: [PATCH v3 13/19] selftests: ublk: add utility to get block device metadata size
Posted by Caleb Sander Mateos 1 month ago
On Tue, Jan 6, 2026 at 5:50 AM Ming Lei <ming.lei@redhat.com> wrote:
>
> On Mon, Jan 05, 2026 at 05:57:45PM -0700, Caleb Sander Mateos wrote:
> > Some block device integrity parameters are available in sysfs, but
> > others are only accessible using the FS_IOC_GETLBMD_CAP ioctl. Add a
> > metadata_size utility program to print out the logical block metadata
> > size, PI offset, and PI size within the metadata. Example output:
> > $ metadata_size /dev/ublkb0
> > metadata_size: 64
> > pi_offset: 56
> > pi_tuple_size: 8
> >
> > Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
> > ---
> >  tools/testing/selftests/ublk/Makefile        |  4 +--
> >  tools/testing/selftests/ublk/metadata_size.c | 36 ++++++++++++++++++++
> >  2 files changed, 38 insertions(+), 2 deletions(-)
> >  create mode 100644 tools/testing/selftests/ublk/metadata_size.c
> >
> > diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile
> > index 06ba6fde098d..41f776bb86a6 100644
> > --- a/tools/testing/selftests/ublk/Makefile
> > +++ b/tools/testing/selftests/ublk/Makefile
> > @@ -47,14 +47,14 @@ TEST_PROGS += test_stress_03.sh
> >  TEST_PROGS += test_stress_04.sh
> >  TEST_PROGS += test_stress_05.sh
> >  TEST_PROGS += test_stress_06.sh
> >  TEST_PROGS += test_stress_07.sh
> >
> > -TEST_GEN_PROGS_EXTENDED = kublk
> > +TEST_GEN_PROGS_EXTENDED = kublk metadata_size
> >
> >  LOCAL_HDRS += $(wildcard *.h)
> >  include ../lib.mk
> >
> > -$(TEST_GEN_PROGS_EXTENDED): $(wildcard *.c)
> > +$(OUTPUT)/kublk: common.c fault_inject.c file_backed.c kublk.c null.c stripe.c
>
> I feel wildcard is pretty handy, can we avoid to kill it? Such as:
>
> STANDALONE_UTILS := metadata_size.c
> KUBLK_SRCS := $(filter-out $(STANDALONE_UTILS),$(wildcard *.c))

Sure, I wasn't aware of filter-out. I'm fine with that.

Thanks,
Caleb