1 files changed, 67 insertions, 0 deletions

diff --git a/tools/testing/selftests/tmpfs/bug-link-o-tmpfile.c b/tools/testing/selftests/tmpfs/bug-link-o-tmpfile.c
new file mode 100644
index 000000000000..b5c3ddb90942
--- /dev/null
+++ b/tools/testing/selftests/tmpfs/bug-link-o-tmpfile.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2019 Alexey Dobriyan <adobriyan@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/* Test that open(O_TMPFILE), linkat() doesn't screw accounting. */
+#include <errno.h>
+#include <sched.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mount.h>
+#include <unistd.h>
+
+int main(void)
+{
+        int fd;
+
+        if (unshare(CLONE_NEWNS) == -1) {
+                if (errno == ENOSYS || errno == EPERM) {
+                        fprintf(stderr, "error: unshare, errno %d\n", errno);
+                        return 4;
+                }
+                fprintf(stderr, "error: unshare, errno %d\n", errno);
+                return 1;
+        }
+        if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
+                fprintf(stderr, "error: mount '/', errno %d\n", errno);
+                return 1;
+        }
+
+        /* Our heroes: 1 root inode, 1 O_TMPFILE inode, 1 permanent inode. */
+        if (mount(NULL, "/tmp", "tmpfs", 0, "nr_inodes=3") == -1) {
+                fprintf(stderr, "error: mount tmpfs, errno %d\n", errno);
+                return 1;
+        }
+
+        fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_TMPFILE, 0600);
+        if (fd == -1) {
+                fprintf(stderr, "error: open 1, errno %d\n", errno);
+                return 1;
+        }
+        if (linkat(fd, "", AT_FDCWD, "/tmp/1", AT_EMPTY_PATH) == -1) {
+                fprintf(stderr, "error: linkat, errno %d\n", errno);
+                return 1;
+        }
+        close(fd);
+
+        fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_TMPFILE, 0600);
+        if (fd == -1) {
+                fprintf(stderr, "error: open 2, errno %d\n", errno);
+                return 1;
+        }
+
+        return 0;
+}