[PATCH] Test seeks from LLONG_MIN

[Matthew Wilcox <willy@infradead.org>]

We don't currently test seeking from LLONG_MIN, which apparently can
produce an UBSAN warning, although I've been unable to reproduce that.
In any case, it's a good corner case to test and straightforward to add.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

diff --git a/src/seek_sanity_test.c b/src/seek_sanity_test.c
index cb036f7b..76587b7f 100644
--- a/src/seek_sanity_test.c
+++ b/src/seek_sanity_test.c
@@ -395,8 +395,12 @@ static int test18(int fd, int testnum)
 	int ret = 0;
 
 	/* file size doesn't matter in this test, set to 0 */
+	ftruncate(fd, 0);
+
 	ret += do_lseek(testnum, 1, fd, 0, SEEK_HOLE, -1, -1);
 	ret += do_lseek(testnum, 2, fd, 0, SEEK_DATA, -1, -1);
+	ret += do_lseek(testnum, 3, fd, 0, SEEK_HOLE, LLONG_MIN, -1);
+	ret += do_lseek(testnum, 4, fd, 0, SEEK_DATA, LLONG_MIN, -1);
 
 	return ret;
 }