Make gofer.dentry.destroyLocked idempotent

gofer operations accumulate dentries touched in a slice to call
checkCachingLocked on them when the operation is over. In case
the same dentry is touched multiple times during the operation,
checkCachingLocked, and consequently destroyLocked, may be called
more than once for the same dentry.

Updates #1198

PiperOrigin-RevId: 305276819

1 files changed, 22 insertions, 0 deletions

diff --git a/test/syscalls/linux/open.cc b/test/syscalls/linux/open.cc
index 267ae19f6..640fe6bfc 100644
--- a/test/syscalls/linux/open.cc
+++ b/test/syscalls/linux/open.cc
@@ -186,6 +186,28 @@ TEST_F(OpenTest, OpenNoFollowStillFollowsLinksInPath) {
       ASSERT_NO_ERRNO_AND_VALUE(Open(path_via_symlink, O_RDONLY | O_NOFOLLOW));
 }
 
+// Test that open(2) can follow symlinks that point back to the same tree.
+// Test sets up files as follows:
+//   root/child/symlink => redirects to ../..
+//   root/child/target => regular file
+//
+// open("root/child/symlink/root/child/file")
+TEST_F(OpenTest, SymlinkRecurse) {
+  auto root =
+      ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDirIn(GetAbsoluteTestTmpdir()));
+  auto child = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDirIn(root.path()));
+  auto symlink = ASSERT_NO_ERRNO_AND_VALUE(
+      TempPath::CreateSymlinkTo(child.path(), "../.."));
+  auto target = ASSERT_NO_ERRNO_AND_VALUE(
+      TempPath::CreateFileWith(child.path(), "abc", 0644));
+  auto path_via_symlink =
+      JoinPath(symlink.path(), Basename(root.path()), Basename(child.path()),
+               Basename(target.path()));
+  const auto contents =
+      ASSERT_NO_ERRNO_AND_VALUE(GetContents(path_via_symlink));
+  ASSERT_EQ(contents, "abc");
+}
+
 TEST_F(OpenTest, Fault) {
   char* totally_not_null = nullptr;
   ASSERT_THAT(open(totally_not_null, O_RDONLY), SyscallFailsWithErrno(EFAULT));