1 files changed, 66 insertions, 6 deletions

diff --git a/test/syscalls/linux/mount.cc b/test/syscalls/linux/mount.cc
index a3e9745cf..d65b7d031 100644
--- a/test/syscalls/linux/mount.cc
+++ b/test/syscalls/linux/mount.cc
@@ -34,6 +34,7 @@
 #include "test/util/mount_util.h"
 #include "test/util/multiprocess_util.h"
 #include "test/util/posix_error.h"
+#include "test/util/save_util.h"
 #include "test/util/temp_path.h"
 #include "test/util/test_util.h"
 #include "test/util/thread_util.h"
@@ -131,7 +132,9 @@ TEST(MountTest, UmountDetach) {
       ASSERT_NO_ERRNO_AND_VALUE(Mount("", dir.path(), "tmpfs", 0, "mode=0700",
                                       /* umountflags= */ MNT_DETACH));
   const struct stat after = ASSERT_NO_ERRNO_AND_VALUE(Stat(dir.path()));
-  EXPECT_NE(before.st_ino, after.st_ino);
+  EXPECT_FALSE(before.st_dev == after.st_dev && before.st_ino == after.st_ino)
+      << "mount point has device number " << before.st_dev
+      << " and inode number " << before.st_ino << " before and after mount";
 
   // Create files in the new mount.
   constexpr char kContents[] = "no no no";
@@ -147,8 +150,17 @@ TEST(MountTest, UmountDetach) {
   // Unmount the tmpfs.
   mount.Release()();
 
-  const struct stat after2 = ASSERT_NO_ERRNO_AND_VALUE(Stat(dir.path()));
-  EXPECT_EQ(before.st_ino, after2.st_ino);
+  // Inode numbers for gofer-accessed files may change across save/restore.
+  //
+  // For overlayfs, if xino option is not enabled and if all overlayfs layers do
+  // not belong to the same filesystem then "the value of st_ino for directory
+  // objects may not be persistent and could change even while the overlay
+  // filesystem is mounted."  -- Documentation/filesystems/overlayfs.txt
+  if (!IsRunningWithSaveRestore() &&
+      !ASSERT_NO_ERRNO_AND_VALUE(IsOverlayfs(dir.path()))) {
+    const struct stat after2 = ASSERT_NO_ERRNO_AND_VALUE(Stat(dir.path()));
+    EXPECT_EQ(before.st_ino, after2.st_ino);
+  }
 
   // Can still read file after unmounting.
   std::vector<char> buf(sizeof(kContents));
@@ -207,14 +219,26 @@ TEST(MountTest, MountTmpfs) {
 
     const struct stat s = ASSERT_NO_ERRNO_AND_VALUE(Stat(dir.path()));
     EXPECT_EQ(s.st_mode, S_IFDIR | 0700);
-    EXPECT_NE(s.st_ino, before.st_ino);
+    EXPECT_FALSE(before.st_dev == s.st_dev && before.st_ino == s.st_ino)
+        << "mount point has device number " << before.st_dev
+        << " and inode number " << before.st_ino << " before and after mount";
 
     EXPECT_NO_ERRNO(Open(JoinPath(dir.path(), "foo"), O_CREAT | O_RDWR, 0777));
   }
 
   // Now that dir is unmounted again, we should have the old inode back.
-  const struct stat after = ASSERT_NO_ERRNO_AND_VALUE(Stat(dir.path()));
-  EXPECT_EQ(before.st_ino, after.st_ino);
+  //
+  // Inode numbers for gofer-accessed files may change across save/restore.
+  //
+  // For overlayfs, if xino option is not enabled and if all overlayfs layers do
+  // not belong to the same filesystem then "the value of st_ino for directory
+  // objects may not be persistent and could change even while the overlay
+  // filesystem is mounted."  -- Documentation/filesystems/overlayfs.txt
+  if (!IsRunningWithSaveRestore() &&
+      !ASSERT_NO_ERRNO_AND_VALUE(IsOverlayfs(dir.path()))) {
+    const struct stat after = ASSERT_NO_ERRNO_AND_VALUE(Stat(dir.path()));
+    EXPECT_EQ(before.st_ino, after.st_ino);
+  }
 }
 
 TEST(MountTest, MountTmpfsMagicValIgnored) {
@@ -321,6 +345,42 @@ TEST(MountTest, RenameRemoveMountPoint) {
   ASSERT_THAT(rmdir(dir.path().c_str()), SyscallFailsWithErrno(EBUSY));
 }
 
+TEST(MountTest, MountFuseFilesystemNoDevice) {
+  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_SYS_ADMIN)));
+  SKIP_IF(IsRunningOnGvisor() && !IsFUSEEnabled());
+
+  auto const dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
+
+  // Before kernel version 4.16-rc6, FUSE mount is protected by
+  // capable(CAP_SYS_ADMIN). After this version, it uses
+  // ns_capable(CAP_SYS_ADMIN) to protect. Before the 4.16 kernel, it was not
+  // allowed to mount fuse file systems without the global CAP_SYS_ADMIN.
+  int res = mount("", dir.path().c_str(), "fuse", 0, "");
+  SKIP_IF(!IsRunningOnGvisor() && res == -1 && errno == EPERM);
+
+  EXPECT_THAT(mount("", dir.path().c_str(), "fuse", 0, ""),
+              SyscallFailsWithErrno(EINVAL));
+}
+
+TEST(MountTest, MountFuseFilesystem) {
+  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_SYS_ADMIN)));
+  SKIP_IF(IsRunningOnGvisor() && !IsFUSEEnabled());
+
+  const FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/fuse", O_WRONLY));
+  std::string mopts = "fd=" + std::to_string(fd.get());
+
+  auto const dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
+
+  // See comments in MountFuseFilesystemNoDevice for the reason why we skip
+  // EPERM when running on Linux.
+  int res = mount("", dir.path().c_str(), "fuse", 0, "");
+  SKIP_IF(!IsRunningOnGvisor() && res == -1 && errno == EPERM);
+
+  auto const mount =
+      ASSERT_NO_ERRNO_AND_VALUE(Mount("", dir.path(), "fuse", 0, mopts, 0));
+}
+
 }  // namespace
 
 }  // namespace testing