[LTP] [PATCH v1] fstat_02: Increase test coverage by creating hard links to file and validate using fstat

[Kushal Chand]

This patch creates a hard link for a file during setup and checks if number of hardlinks
match with the expected number.

This is discussed here: https://github.com/linux-test-project/ltp/issues/517#issuecomment-533035589

Implements: #517
---
 testcases/kernel/syscalls/fstat/fstat02.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/testcases/kernel/syscalls/fstat/fstat02.c b/testcases/kernel/syscalls/fstat/fstat02.c
index c0229de44..f6f6ca456 100644
--- a/testcases/kernel/syscalls/fstat/fstat02.c
+++ b/testcases/kernel/syscalls/fstat/fstat02.c
@@ -17,8 +17,10 @@
 #include "tst_safe_macros.h"
 
 #define TESTFILE        "test_file"
+#define LINK_TESTFILE   "link_test_file"
 #define FILE_SIZE       1024
 #define FILE_MODE	0644
+#define NLINK	        2
 
 static struct stat stat_buf;
 static uid_t user_id;
@@ -61,6 +63,12 @@ static void run(void)
 		fail++;
 	}
 
+	if (stat_buf.st_nlink != NLINK) {
+		tst_res(TFAIL, "stat_buf.st_nlink = %lu expected %o",
+			(stat_buf.st_nlink), NLINK);
+		fail++;
+	}
+
 	if (fail)
 		return;
 
@@ -78,6 +86,8 @@ static void setup(void)
 
 	if (tst_fill_file(TESTFILE, 'a', FILE_SIZE, 1))
 		tst_brk(TBROK, "Could not fill Testfile!");
+
+	SAFE_LINK(TESTFILE, LINK_TESTFILE);
 }
 
 static void cleanup(void)
-- 
2.25.1