[LTP] [PATCH] syscalls/ustat: Skip tests on Btrfs using TCONF

[Disha Goel]

The ustat(2) system call is known to fail with EINVAL on Btrfs because
it uses anonymous device IDs for subvolumes, which the legacy syscall
cannot resolve to a physical block device.

Currently, this results in a TFAIL, which causes false negatives in
automated CI environments (e.g., SLES). This patch adds dynamic
filesystem detection in setup() and uses tst_brk(TCONF, ...) to
gracefully skip the test on Btrfs.

Changes:
  - Added sys/vfs.h for statfs support.
  - Implemented Btrfs magic number detection in setup().
  - Used tst_brk(TCONF, ...) to skip the test if Btrfs is detected.

Verified on:
  - SLES (Btrfs): Result is now TCONF (Skipped)
  - RHEL (XFS): Result remains TPASS

Signed-off-by: Disha Goel <disgoel@linux.ibm.com>
---
 testcases/kernel/syscalls/ustat/ustat01.c | 8 +++++++-
 testcases/kernel/syscalls/ustat/ustat02.c | 8 +++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/testcases/kernel/syscalls/ustat/ustat01.c b/testcases/kernel/syscalls/ustat/ustat01.c
index 161006058..07ee2faf7 100644
--- a/testcases/kernel/syscalls/ustat/ustat01.c
+++ b/testcases/kernel/syscalls/ustat/ustat01.c
@@ -13,6 +13,7 @@
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/vfs.h>
 
 #include "lapi/syscalls.h"
 #include "lapi/ustat.h"
@@ -34,11 +35,16 @@ void run(void)
 static void setup(void)
 {
 	struct stat buf;
+	struct statfs fs_buf;
 
 	/* Find a valid device number */
 	SAFE_STAT("/", &buf);
-
 	dev_num = buf.st_dev;
+
+	statfs("/", &fs_buf);
+	if (fs_buf.f_type == 0x9123683E) {
+		tst_brk(TCONF, "%s", test.tags[0].value);
+	}
 }
 
 static struct tst_test test = {
diff --git a/testcases/kernel/syscalls/ustat/ustat02.c b/testcases/kernel/syscalls/ustat/ustat02.c
index 84becaa1f..789ef57fc 100644
--- a/testcases/kernel/syscalls/ustat/ustat02.c
+++ b/testcases/kernel/syscalls/ustat/ustat02.c
@@ -14,6 +14,7 @@
 #include <errno.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/vfs.h>
 
 #include "lapi/syscalls.h"
 #include "lapi/ustat.h"
@@ -50,11 +51,16 @@ void run(unsigned int test)
 static void setup(void)
 {
 	struct stat buf;
+	struct statfs fs_buf;
 
 	/* Find a valid device number */
 	SAFE_STAT("/", &buf);
-
 	root_dev = buf.st_dev;
+
+	statfs("/", &fs_buf);
+	if (fs_buf.f_type == 0x9123683E) {
+		tst_brk(TCONF, "%s", test.tags[0].value);
+	}
 }
 
 static struct tst_test test = {
-- 
2.45.1