cmd/link: accept extra blocks in TestFallocate

For #41127

Change-Id: I794a082299c6dce4202223197ece1864bed36810
Reviewed-on: https://go-review.googlesource.com/c/go/+/282555
Trust: Ian Lance Taylor <[email protected]>
Reviewed-by: Austin Clements <[email protected]>

Author: ianlancetaylor

src/cmd/link/internal/ld/fallocate_test.go

@@ -57,8 +57,12 @@ func TestFallocate(t *testing.T) {
 		if got := stat.Size(); got != sz {
 			t.Errorf("unexpected file size: got %d, want %d", got, sz)
 		}
-		if got, want := stat.Sys().(*syscall.Stat_t).Blocks, (sz+511)/512; got != want {
-			t.Errorf("unexpected disk usage: got %d blocks, want %d", got, want)
+		// The number of blocks must be enough for the requested size.
+		// We used to require an exact match, but it appears that
+		// some file systems allocate a few extra blocks in some cases.
+		// See issue #41127.
+		if got, want := stat.Sys().(*syscall.Stat_t).Blocks, (sz+511)/512; got < want {
+			t.Errorf("unexpected disk usage: got %d blocks, want at least %d", got, want)
 		}
 		out.munmap()
 	}