[vfs] Disable nlink tests for overlayfs.

Overlayfs intentionally does not compute nlink for directories (because it can
be really expensive). Linux returns 1, VFS2 returns 2 and VFS1 actually
calculates the correct value.

PiperOrigin-RevId: 330967139

2 files changed, 10 insertions, 4 deletions

diff --git a/test/syscalls/linux/stat.cc b/test/syscalls/linux/stat.cc
index 2503960f3..1b2941c37 100644
--- a/test/syscalls/linux/stat.cc
+++ b/test/syscalls/linux/stat.cc
@@ -97,6 +97,11 @@ TEST_F(StatTest, FstatatSymlink) {
 }
 
 TEST_F(StatTest, Nlinks) {
+  // Skip this test if we are testing overlayfs because overlayfs does not
+  // (intentionally) return the correct nlink value for directories.
+  // See fs/overlayfs/inode.c:ovl_getattr().
+  SKIP_IF(ASSERT_NO_ERRNO_AND_VALUE(IsOverlayfs(GetAbsoluteTestTmpdir())));
+
   TempPath basedir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
 
   // Directory is initially empty, it should contain 2 links (one from itself,
@@ -432,6 +437,11 @@ TEST_F(StatTest, ZeroLinksOpenFdRegularFileChild_NoRandomSave) {
 
 // Test link counts with a directory as the child.
 TEST_F(StatTest, LinkCountsWithDirChild) {
+  // Skip this test if we are testing overlayfs because overlayfs does not
+  // (intentionally) return the correct nlink value for directories.
+  // See fs/overlayfs/inode.c:ovl_getattr().
+  SKIP_IF(ASSERT_NO_ERRNO_AND_VALUE(IsOverlayfs(GetAbsoluteTestTmpdir())));
+
   const TempPath dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
 
   // Before a child is added the two links are "." and the link from the parent.
diff --git a/test/syscalls/linux/statfs.cc b/test/syscalls/linux/statfs.cc
index 99ab280fd..f0fb166bd 100644
--- a/test/syscalls/linux/statfs.cc
+++ b/test/syscalls/linux/statfs.cc
@@ -27,10 +27,6 @@ namespace testing {
 
 namespace {
 
-// From linux/magic.h. For some reason, not defined in the headers for some
-// build environments.
-#define OVERLAYFS_SUPER_MAGIC 0x794c7630
-
 TEST(StatfsTest, CannotStatBadPath) {
   auto temp_file = NewTempAbsPathInDir("/tmp");