Support VFS2 save/restore.

Inode number consistency checks are now skipped in save/restore tests for
reasons described in greatest detail in StatTest.StateDoesntChangeAfterRename.
They pass in VFS1 due to the bug described in new test case
SimpleStatTest.DifferentFilesHaveDifferentDeviceInodeNumberPairs.

Fixes #1663

PiperOrigin-RevId: 338776148

5 files changed, 81 insertions, 25 deletions

diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index 572f39a5d..42fa18683 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -1285,6 +1285,7 @@ cc_binary(
         "//test/util:mount_util",
         "//test/util:multiprocess_util",
         "//test/util:posix_error",
+        "//test/util:save_util",
         "//test/util:temp_path",
         "//test/util:test_main",
         "//test/util:test_util",
@@ -3441,6 +3442,7 @@ cc_binary(
         "@com_google_absl//absl/strings",
         gtest,
         "//test/util:posix_error",
+        "//test/util:save_util",
         "//test/util:temp_path",
         "//test/util:test_main",
         "//test/util:test_util",
diff --git a/test/syscalls/linux/mknod.cc b/test/syscalls/linux/mknod.cc
index b96907b30..1635c6d0c 100644
--- a/test/syscalls/linux/mknod.cc
+++ b/test/syscalls/linux/mknod.cc
@@ -125,6 +125,16 @@ TEST(MknodTest, Socket) {
   ASSERT_THAT(unlink(filename.c_str()), SyscallSucceeds());
 }
 
+PosixErrorOr<FileDescriptor> OpenRetryEINTR(std::string const& path, int flags,
+                                            mode_t mode = 0) {
+  while (true) {
+    auto maybe_fd = Open(path, flags, mode);
+    if (maybe_fd.ok() || maybe_fd.error().errno_value() != EINTR) {
+      return maybe_fd;
+    }
+  }
+}
+
 TEST(MknodTest, Fifo) {
   const std::string fifo = NewTempAbsPath();
   ASSERT_THAT(mknod(fifo.c_str(), S_IFIFO | S_IRUSR | S_IWUSR, 0),
@@ -139,14 +149,16 @@ TEST(MknodTest, Fifo) {
 
   // Read-end of the pipe.
   ScopedThread t([&fifo, &buf, &msg]() {
-    FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(fifo.c_str(), O_RDONLY));
+    FileDescriptor fd =
+        ASSERT_NO_ERRNO_AND_VALUE(OpenRetryEINTR(fifo.c_str(), O_RDONLY));
     EXPECT_THAT(ReadFd(fd.get(), buf.data(), buf.size()),
                 SyscallSucceedsWithValue(msg.length()));
     EXPECT_EQ(msg, std::string(buf.data()));
   });
 
   // Write-end of the pipe.
-  FileDescriptor wfd = ASSERT_NO_ERRNO_AND_VALUE(Open(fifo.c_str(), O_WRONLY));
+  FileDescriptor wfd =
+      ASSERT_NO_ERRNO_AND_VALUE(OpenRetryEINTR(fifo.c_str(), O_WRONLY));
   EXPECT_THAT(WriteFd(wfd.get(), msg.c_str(), msg.length()),
               SyscallSucceedsWithValue(msg.length()));
 }
@@ -164,15 +176,16 @@ TEST(MknodTest, FifoOtrunc) {
   std::vector<char> buf(512);
   // Read-end of the pipe.
   ScopedThread t([&fifo, &buf, &msg]() {
-    FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(fifo.c_str(), O_RDONLY));
+    FileDescriptor fd =
+        ASSERT_NO_ERRNO_AND_VALUE(OpenRetryEINTR(fifo.c_str(), O_RDONLY));
     EXPECT_THAT(ReadFd(fd.get(), buf.data(), buf.size()),
                 SyscallSucceedsWithValue(msg.length()));
     EXPECT_EQ(msg, std::string(buf.data()));
   });
 
   // Write-end of the pipe.
-  FileDescriptor wfd =
-      ASSERT_NO_ERRNO_AND_VALUE(Open(fifo.c_str(), O_WRONLY | O_TRUNC));
+  FileDescriptor wfd = ASSERT_NO_ERRNO_AND_VALUE(
+      OpenRetryEINTR(fifo.c_str(), O_WRONLY | O_TRUNC));
   EXPECT_THAT(WriteFd(wfd.get(), msg.c_str(), msg.length()),
               SyscallSucceedsWithValue(msg.length()));
 }
@@ -192,14 +205,15 @@ TEST(MknodTest, FifoTruncNoOp) {
   std::vector<char> buf(512);
   // Read-end of the pipe.
   ScopedThread t([&fifo, &buf, &msg]() {
-    FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(fifo.c_str(), O_RDONLY));
+    FileDescriptor fd =
+        ASSERT_NO_ERRNO_AND_VALUE(OpenRetryEINTR(fifo.c_str(), O_RDONLY));
     EXPECT_THAT(ReadFd(fd.get(), buf.data(), buf.size()),
                 SyscallSucceedsWithValue(msg.length()));
     EXPECT_EQ(msg, std::string(buf.data()));
   });
 
-  FileDescriptor wfd =
-      ASSERT_NO_ERRNO_AND_VALUE(Open(fifo.c_str(), O_WRONLY | O_TRUNC));
+  FileDescriptor wfd = ASSERT_NO_ERRNO_AND_VALUE(
+      OpenRetryEINTR(fifo.c_str(), O_WRONLY | O_TRUNC));
   EXPECT_THAT(ftruncate(wfd.get(), 0), SyscallFailsWithErrno(EINVAL));
   EXPECT_THAT(WriteFd(wfd.get(), msg.c_str(), msg.length()),
               SyscallSucceedsWithValue(msg.length()));
diff --git a/test/syscalls/linux/mount.cc b/test/syscalls/linux/mount.cc
index 3aab25b23..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";
@@ -147,12 +150,14 @@ TEST(MountTest, UmountDetach) {
   // Unmount the tmpfs.
   mount.Release()();
 
-  // Only check for inode number equality if the directory is not in 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 (!ASSERT_NO_ERRNO_AND_VALUE(IsOverlayfs(dir.path()))) {
+  // 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);
   }
@@ -214,18 +219,23 @@ 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.
-  // Only check for inode number equality if the directory is not in 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 (!ASSERT_NO_ERRNO_AND_VALUE(IsOverlayfs(dir.path()))) {
+  //
+  // 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);
   }
diff --git a/test/syscalls/linux/proc_pid_smaps.cc b/test/syscalls/linux/proc_pid_smaps.cc
index 9fb1b3a2c..738923822 100644
--- a/test/syscalls/linux/proc_pid_smaps.cc
+++ b/test/syscalls/linux/proc_pid_smaps.cc
@@ -191,7 +191,7 @@ PosixErrorOr<std::vector<ProcPidSmapsEntry>> ParseProcPidSmaps(
     // amount of whitespace).
     if (!entry) {
       std::cerr << "smaps line not considered a maps line: "
-                << maybe_maps_entry.error_message() << std::endl;
+                << maybe_maps_entry.error().message() << std::endl;
       return PosixError(
           EINVAL,
           absl::StrCat("smaps field line without preceding maps line: ", l));
diff --git a/test/syscalls/linux/stat.cc b/test/syscalls/linux/stat.cc
index 92260b1e1..6e7142a42 100644
--- a/test/syscalls/linux/stat.cc
+++ b/test/syscalls/linux/stat.cc
@@ -31,6 +31,7 @@
 #include "test/util/cleanup.h"
 #include "test/util/file_descriptor.h"
 #include "test/util/fs_util.h"
+#include "test/util/save_util.h"
 #include "test/util/temp_path.h"
 #include "test/util/test_util.h"
 
@@ -328,7 +329,10 @@ TEST_F(StatTest, LeadingDoubleSlash) {
   ASSERT_THAT(lstat(double_slash_path.c_str(), &double_slash_st),
               SyscallSucceeds());
   EXPECT_EQ(st.st_dev, double_slash_st.st_dev);
-  EXPECT_EQ(st.st_ino, double_slash_st.st_ino);
+  // Inode numbers for gofer-accessed files may change across save/restore.
+  if (!IsRunningWithSaveRestore()) {
+    EXPECT_EQ(st.st_ino, double_slash_st.st_ino);
+  }
 }
 
 // Test that a rename doesn't change the underlying file.
@@ -346,8 +350,14 @@ TEST_F(StatTest, StatDoesntChangeAfterRename) {
 
   EXPECT_EQ(st_old.st_nlink, st_new.st_nlink);
   EXPECT_EQ(st_old.st_dev, st_new.st_dev);
+  // Inode numbers for gofer-accessed files on which no reference is held may
+  // change across save/restore because the information that the gofer client
+  // uses to track file identity (9P QID path) is inconsistent between gofer
+  // processes, which are restarted across save/restore.
+  //
   // Overlay filesystems may synthesize directory inode numbers on the fly.
-  if (!ASSERT_NO_ERRNO_AND_VALUE(IsOverlayfs(GetAbsoluteTestTmpdir()))) {
+  if (!IsRunningWithSaveRestore() &&
+      !ASSERT_NO_ERRNO_AND_VALUE(IsOverlayfs(GetAbsoluteTestTmpdir()))) {
     EXPECT_EQ(st_old.st_ino, st_new.st_ino);
   }
   EXPECT_EQ(st_old.st_mode, st_new.st_mode);
@@ -541,6 +551,26 @@ TEST_F(StatTest, LstatELOOPPath) {
   ASSERT_THAT(lstat(path.c_str(), &s), SyscallFailsWithErrno(ELOOP));
 }
 
+TEST(SimpleStatTest, DifferentFilesHaveDifferentDeviceInodeNumberPairs) {
+  // TODO(gvisor.dev/issue/1624): This test case fails in VFS1 save/restore
+  // tests because VFS1 gofer inode number assignment restarts after
+  // save/restore, such that the inodes for file1 and file2 (which are
+  // unreferenced and therefore not retained in sentry checkpoints before the
+  // calls to lstat()) are assigned the same inode number.
+  SKIP_IF(IsRunningWithVFS1() && IsRunningWithSaveRestore());
+
+  TempPath file1 = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
+  TempPath file2 = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
+
+  MaybeSave();
+  struct stat st1 = ASSERT_NO_ERRNO_AND_VALUE(Lstat(file1.path()));
+  MaybeSave();
+  struct stat st2 = ASSERT_NO_ERRNO_AND_VALUE(Lstat(file2.path()));
+  EXPECT_FALSE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino)
+      << "both files have device number " << st1.st_dev << " and inode number "
+      << st1.st_ino;
+}
+
 // Ensure that inode allocation for anonymous devices work correctly across
 // save/restore. In particular, inode numbers should be unique across S/R.
 TEST(SimpleStatTest, AnonDeviceAllocatesUniqueInodesAcrossSaveRestore) {