[LTP] [PATCH v2 26/31] testcases: sysfs: Add sys_block_size01

A test for /sys/block/*/{ro, size} files.

Signed-off-by: Cyril Hrubis <[email protected]>
---
 runtest/sysfs                                 |   1 +
 testcases/kernel/sysfs/block/.gitignore       |   1 +
 .../kernel/sysfs/block/sys_block_size01.c     | 102 ++++++++++++++++++
 3 files changed, 104 insertions(+)
 create mode 100644 testcases/kernel/sysfs/block/sys_block_size01.c

diff --git a/runtest/sysfs b/runtest/sysfs
index f7d35e0c2..46593b82f 100644
--- a/runtest/sysfs
+++ b/runtest/sysfs
@@ -21,3 +21,4 @@ sys_net03 sys_net03
 sys_net04 sys_net04
 sys_block_loop01 sys_block_loop01
 sys_block_queue01 sys_block_queue01
+sys_block_size01 sys_block_size01
diff --git a/testcases/kernel/sysfs/block/.gitignore b/testcases/kernel/sysfs/block/.gitignore
index c7011b79f..9fd4a1d82 100644
--- a/testcases/kernel/sysfs/block/.gitignore
+++ b/testcases/kernel/sysfs/block/.gitignore
@@ -1,2 +1,3 @@
 /sys_block_loop01
 /sys_block_queue01
+/sys_block_size01
diff --git a/testcases/kernel/sysfs/block/sys_block_size01.c b/testcases/kernel/sysfs/block/sys_block_size01.c
new file mode 100644
index 000000000..f974be9aa
--- /dev/null
+++ b/testcases/kernel/sysfs/block/sys_block_size01.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2026 Cyril Hrubis <[email protected]>
+ */
+
+/*\
+ * Cross-checks the block device size reported in sysfs against /proc/partitions.
+ *
+ * /sys/block/<dev>/size holds the device size in 512 byte sectors while
+ * /proc/partitions lists the size in 1024 byte blocks. For every whole block
+ * device the test verifies that:
+ *
+ * - the two sources agree, i.e. sysfs_size_in_sectors / 2 == proc_blocks
+ * - the ro (read-only) attribute is a boolean
+ *
+ * The test skips with TCONF when a device is not present in /proc/partitions
+ * (for example device-mapper devices that are only listed under /sys/block).
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <dirent.h>
+#include "tst_test.h"
+#include "tst_safe_stdio.h"
+#include "tst_sysfs_assert.h"
+
+#define SYS_BLOCK "/sys/block"
+
+static int proc_partition_blocks(const char *dev, long long *blocks)
+{
+	FILE *f;
+	char line[4096];
+	int found = 0;
+
+	f = SAFE_FOPEN("/proc/partitions", "r");
+
+	while (fgets(line, sizeof(line), f)) {
+		long long nblocks;
+		char name[256];
+
+		if (sscanf(line, "%*u %*u %lld %255s", &nblocks, name) != 2)
+			continue;
+
+		if (!strcmp(name, dev)) {
+			*blocks = nblocks;
+			found = 1;
+			break;
+		}
+	}
+
+	SAFE_FCLOSE(f);
+
+	return found;
+}
+
+static void check_device(const char *dev)
+{
+	long long sectors, proc_blocks;
+
+	tst_res(TINFO, "Checking block device '%s'", dev);
+
+	TST_SYSFS_ASSERT_BOOL(SYS_BLOCK "/%s/ro", dev);
+
+	if (!proc_partition_blocks(dev, &proc_blocks)) {
+		tst_res(TCONF, "%s not listed in /proc/partitions", dev);
+		return;
+	}
+
+	sectors = TST_SYSFS_READ_LLI(SYS_BLOCK "/%s/size", dev);
+
+	/* sysfs size is in 512 byte sectors, /proc/partitions in 1024 byte blocks */
+	if (sectors / 2 == proc_blocks) {
+		tst_res(TPASS,
+			"%s: sysfs size %lld sectors matches /proc/partitions %lld blocks",
+			dev, sectors, proc_blocks);
+	} else {
+		tst_res(TFAIL,
+			"%s: sysfs size %lld sectors (/2 = %lld) != /proc/partitions %lld blocks",
+			dev, sectors, sectors / 2, proc_blocks);
+	}
+}
+
+static void do_test(void)
+{
+	DIR *d;
+	struct dirent *ent;
+
+	d = SAFE_OPENDIR(SYS_BLOCK);
+
+	while ((ent = SAFE_READDIR(d))) {
+		if (ent->d_name[0] == '.')
+			continue;
+
+		check_device(ent->d_name);
+	}
+
+	SAFE_CLOSEDIR(d);
+}
+
+static struct tst_test test = {
+	.test_all = do_test,
+};
-- 
2.54.0


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