[LTP] [PATCH v2] syscalls/ustat: Skip tests on Btrfs using .skip_filesystems

[Disha Goel]

The ustat(2) system call is known to fail with EINVAL on Btrfs because
it uses anonymous device IDs for subvolumes, which this 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 utilizes the LTP
library's .skip_filesystems mechanism to gracefully skip the tests
(TCONF) when executed on Btrfs.

Signed-off-by: Disha Goel <disgoel@linux.ibm.com>
---
Changelog v1 -> v2:
- Removed manual statfs/tst_brk logic in setup().
- Implemented .skip_filesystems in the tst_test structure for both
  ustat01 and ustat02.

Link to v1:
https://lore.kernel.org/all/20260318082438.50245-1-disgoel@linux.ibm.com/
---
 testcases/kernel/syscalls/ustat/ustat01.c | 4 ++++
 testcases/kernel/syscalls/ustat/ustat02.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/testcases/kernel/syscalls/ustat/ustat01.c b/testcases/kernel/syscalls/ustat/ustat01.c
index 161006058..55095191b 100644
--- a/testcases/kernel/syscalls/ustat/ustat01.c
+++ b/testcases/kernel/syscalls/ustat/ustat01.c
@@ -44,6 +44,10 @@ static void setup(void)
 static struct tst_test test = {
 	.test_all = run,
 	.setup = setup,
+	.skip_filesystems = (const char *const[]) {
+                "btrfs",
+                NULL
+        },
 	.tags = (const struct tst_tag[]) {
 		{"known-fail", "ustat() is known to fail with EINVAL on Btrfs, see "
 			"https://lore.kernel.org/linux-btrfs/e7e867b8-b57a-7eb2-2432-1627bd3a88fb@toxicpanda.com/"
diff --git a/testcases/kernel/syscalls/ustat/ustat02.c b/testcases/kernel/syscalls/ustat/ustat02.c
index 84becaa1f..82dcfb6b4 100644
--- a/testcases/kernel/syscalls/ustat/ustat02.c
+++ b/testcases/kernel/syscalls/ustat/ustat02.c
@@ -61,6 +61,10 @@ static struct tst_test test = {
 	.test = run,
 	.setup = setup,
 	.tcnt = ARRAY_SIZE(tc),
+	.skip_filesystems = (const char *const[]) {
+                "btrfs",
+                NULL
+        },
 	.tags = (const struct tst_tag[]) {
 		{"known-fail", "ustat() is known to fail with EINVAL on Btrfs, see "
 			"https://lore.kernel.org/linux-btrfs/e7e867b8-b57a-7eb2-2432-1627bd3a88fb@toxicpanda.com/"
-- 
2.45.1