From a33228682c2039f086823ac798242734ec0eb4e5 Mon Sep 17 00:00:00 2001
From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Tue, 5 Mar 2019 15:49:24 -0800
Subject: [PATCH] tmpfs: test link accounting with O_TMPFILE
Mount tmpfs with "nr_inodes=3" for easy check.
Link: http://lkml.kernel.org/r/20190219215016.GA20084@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matej Kupljen <matej.kupljen@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/tmpfs/.gitignore | 1 +
tools/testing/selftests/tmpfs/Makefile | 7 ++
.../selftests/tmpfs/bug-link-o-tmpfile.c | 67 +++++++++++++++++++
4 files changed, 76 insertions(+)
create mode 100644 tools/testing/selftests/tmpfs/.gitignore
create mode 100644 tools/testing/selftests/tmpfs/Makefile
create mode 100644 tools/testing/selftests/tmpfs/bug-link-o-tmpfile.c
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 400ee81a30433..6a94f07c4164a 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -48,6 +48,7 @@ TARGETS += sysctl
ifneq (1, $(quicktest))
TARGETS += timers
endif
+TARGETS += tmpfs
TARGETS += user
TARGETS += vm
TARGETS += x86
diff --git a/tools/testing/selftests/tmpfs/.gitignore b/tools/testing/selftests/tmpfs/.gitignore
new file mode 100644
index 0000000000000..a96838fad74d7
--- /dev/null
+++ b/tools/testing/selftests/tmpfs/.gitignore
@@ -0,0 +1 @@
+/bug-link-o-tmpfile
diff --git a/tools/testing/selftests/tmpfs/Makefile b/tools/testing/selftests/tmpfs/Makefile
new file mode 100644
index 0000000000000..953c81299181e
--- /dev/null
+++ b/tools/testing/selftests/tmpfs/Makefile
@@ -0,0 +1,7 @@
+CFLAGS += -Wall -O2
+CFLAGS += -D_GNU_SOURCE
+
+TEST_GEN_PROGS :=
+TEST_GEN_PROGS += bug-link-o-tmpfile
+
+include ../lib.mk
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 0000000000000..b5c3ddb90942f
--- /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;
+}
--
GitLab