Merge netfs API documentation updates

Bring in the netfs API documentation updates which had been in the
vfs-6.16.misc branch for most of this cycle. So don't needlessly rewrite
the vfs-6.16.misc by dropping it from that branch and moving it to
vfs-6.16.netfs. Simply merge vfs-6.16.misc into vfs-6.16.netfs.

Signed-off-by: Christian Brauner <brauner@kernel.org>

3 files changed, 71 insertions, 1 deletions

diff --git a/tools/testing/selftests/filesystems/.gitignore b/tools/testing/selftests/filesystems/.gitignore
index 828b66a10c63..7afa58e2bb20 100644
--- a/tools/testing/selftests/filesystems/.gitignore
+++ b/tools/testing/selftests/filesystems/.gitignore
@@ -2,3 +2,4 @@
 dnotify_test
 devpts_pts
 file_stressor
+anon_inode_test
diff --git a/tools/testing/selftests/filesystems/Makefile b/tools/testing/selftests/filesystems/Makefile
index 66305fc34c60..b02326193fee 100644
--- a/tools/testing/selftests/filesystems/Makefile
+++ b/tools/testing/selftests/filesystems/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 CFLAGS += $(KHDR_INCLUDES)
-TEST_GEN_PROGS := devpts_pts file_stressor
+TEST_GEN_PROGS := devpts_pts file_stressor anon_inode_test
 TEST_GEN_PROGS_EXTENDED := dnotify_test
 
 include ../lib.mk
diff --git a/tools/testing/selftests/filesystems/anon_inode_test.c b/tools/testing/selftests/filesystems/anon_inode_test.c
new file mode 100644
index 000000000000..e8e0ef1460d2
--- /dev/null
+++ b/tools/testing/selftests/filesystems/anon_inode_test.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#define __SANE_USERSPACE_TYPES__
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/stat.h>
+
+#include "../kselftest_harness.h"
+#include "overlayfs/wrappers.h"
+
+TEST(anon_inode_no_chown)
+{
+	int fd_context;
+
+	fd_context = sys_fsopen("tmpfs", 0);
+	ASSERT_GE(fd_context, 0);
+
+	ASSERT_LT(fchown(fd_context, 1234, 5678), 0);
+	ASSERT_EQ(errno, EOPNOTSUPP);
+
+	EXPECT_EQ(close(fd_context), 0);
+}
+
+TEST(anon_inode_no_chmod)
+{
+	int fd_context;
+
+	fd_context = sys_fsopen("tmpfs", 0);
+	ASSERT_GE(fd_context, 0);
+
+	ASSERT_LT(fchmod(fd_context, 0777), 0);
+	ASSERT_EQ(errno, EOPNOTSUPP);
+
+	EXPECT_EQ(close(fd_context), 0);
+}
+
+TEST(anon_inode_no_exec)
+{
+	int fd_context;
+
+	fd_context = sys_fsopen("tmpfs", 0);
+	ASSERT_GE(fd_context, 0);
+
+	ASSERT_LT(execveat(fd_context, "", NULL, NULL, AT_EMPTY_PATH), 0);
+	ASSERT_EQ(errno, EACCES);
+
+	EXPECT_EQ(close(fd_context), 0);
+}
+
+TEST(anon_inode_no_open)
+{
+	int fd_context;
+
+	fd_context = sys_fsopen("tmpfs", 0);
+	ASSERT_GE(fd_context, 0);
+
+	ASSERT_GE(dup2(fd_context, 500), 0);
+	ASSERT_EQ(close(fd_context), 0);
+	fd_context = 500;
+
+	ASSERT_LT(open("/proc/self/fd/500", 0), 0);
+	ASSERT_EQ(errno, ENXIO);
+
+	EXPECT_EQ(close(fd_context), 0);
+}
+
+TEST_HARNESS_MAIN
+