[PATCH v2 2/4] src/open_by_handle: program to exercise open_by_handle_at() syscall

Amir Goldstein
2017-04-19T16:29:13Z

This is a clone of src/stale_handle.c test that uses generic
open_by_handle_at() syscall instead of the xfs specific ioctl.

No test is using this program yet.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
.gitignore | 1 +
aclocal.m4 | 15 ++++++
configure.ac | 1 +
include/builddefs.in | 1 +
src/Makefile | 4 ++
src/open_by_handle.c | 143 +++++++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 165 insertions(+)
create mode 100644 src/open_by_handle.c

diff --git a/.gitignore b/.gitignore
index 0336555..ded4a61 100644
--- a/.gitignore
+++ b/.gitignore
@@ -80,6 +80,7 @@
/src/multi_open_unlink
/src/nametest
/src/nsexec
+/src/open_by_handle
/src/permname
/src/preallo_rw_pattern_reader
/src/preallo_rw_pattern_writer
diff --git a/aclocal.m4 b/aclocal.m4
index f3412e1..829fa10 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -37,6 +37,21 @@ AC_DEFUN([AC_PACKAGE_WANT_FALLOCATE],
[ have_fallocate=false; AC_MSG_RESULT(no) ])
AC_SUBST(have_fallocate)
])
+
+AC_DEFUN([AC_PACKAGE_WANT_OPEN_BY_HANDLE_AT],
+ [ AC_MSG_CHECKING([for open_by_handle_at])
+ AC_TRY_LINK([
+#define _GNU_SOURCE
+#include <fcntl.h>
+ ],
+ [
+ struct file_handle fh;
+ open_by_handle_at(0, &fh, 0);
+ ],
+ [ have_open_by_handle_at=true; AC_MSG_RESULT(yes) ],
+ [ have_open_by_handle_at=false; AC_MSG_RESULT(no) ])
+ AC_SUBST(have_open_by_handle_at)
+ ])
m4_include([m4/multilib.m4])
m4_include([m4/package_acldev.m4])
m4_include([m4/package_aiodev.m4])
diff --git a/configure.ac b/configure.ac
index 246f92e..1285bf4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -75,6 +75,7 @@ in
AC_PACKAGE_WANT_DMAPI
AC_PACKAGE_WANT_LINUX_FIEMAP_H
AC_PACKAGE_WANT_FALLOCATE
+ AC_PACKAGE_WANT_OPEN_BY_HANDLE_AT
AC_PACKAGE_WANT_LINUX_PRCTL_H
AC_PACKAGE_WANT_LINUX_FS_H
AC_PACKAGE_WANT_SSL
diff --git a/include/builddefs.in b/include/builddefs.in
index 24f838f..2725037 100644
--- a/include/builddefs.in
+++ b/include/builddefs.in
@@ -61,6 +61,7 @@ ENABLE_SHARED = @enable_shared@
HAVE_DB = @have_db@
HAVE_AIO = @have_aio@
HAVE_FALLOCATE = @have_fallocate@
+HAVE_OPEN_BY_HANDLE_AT = @have_open_by_handle_at@
HAVE_SSL = @have_ssl@
HAVE_DMAPI = @have_dmapi@
HAVE_ATTR_LIST = @have_attr_list@
diff --git a/src/Makefile b/src/Makefile
index 247383c..abfd873 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -36,6 +36,10 @@ ifeq ($(HAVE_FIEMAP), true)
LINUX_TARGETS += fiemap-tester
endif

+ifeq ($(HAVE_OPEN_BY_HANDLE_AT), true)
+LINUX_TARGETS += open_by_handle
+endif
+
ifeq ($(HAVE_FALLOCATE), true)
LCFLAGS += -DHAVE_FALLOCATE
endif
diff --git a/src/open_by_handle.c b/src/open_by_handle.c
new file mode 100644
index 0000000..76510ff
--- /dev/null
+++ b/src/open_by_handle.c
@@ -0,0 +1,143 @@
+/*
+ * open_by_handle.c - attempt to create a file handle and open it
+ * with open_by_handle_at() syscall
+ *
+ * Copyright (C) 2017 CTERA Networks. All Rights Reserved.
+ * Author: Amir Goldstein <amir73il@gmail.com>
+ *
+ * from:
+ * stale_handle.c
+ *
+ * Copyright (C) 2010 Red Hat, Inc. All Rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <linux/limits.h>
+
+#define NUMFILES 1024
+
+struct handle {
+ struct file_handle fh;
+ unsigned char fid[MAX_HANDLE_SZ];
+} handle[NUMFILES];
+
+int main(int argc, char **argv)
+{
+ int i;
+ int fd;
+ int ret;
+ int failed = 0;
+ char fname[PATH_MAX];
+ char *test_dir;
+ int mount_fd, mount_id;
+
+ if (argc != 2) {
+ fprintf(stderr, "usage: open_by_handle <test_dir>\n");
+ return EXIT_FAILURE;
+ }
+
+ test_dir = argv[1];
+ mount_fd = open(test_dir, O_RDONLY|O_DIRECTORY);
+ if (mount_fd < 0) {
+ perror("open test_dir");
+ return EXIT_FAILURE;
+ }
+
+ /*
+ * create a large number of files to force allocation of new inode
+ * chunks on disk.
+ */
+ for (i=0; i < NUMFILES; i++) {
+ sprintf(fname, "%s/file%06d", test_dir, i);
+ fd = open(fname, O_RDWR | O_CREAT | O_TRUNC, 0644);
+ if (fd < 0) {
+ printf("Warning (%s,%d), open(%s) failed.\n", __FILE__, __LINE__, fname);
+ perror(fname);
+ return EXIT_FAILURE;
+ }
+ close(fd);
+ }
+
+ /* sync to get the new inodes to hit the disk */
+ sync();
+
+ /* create the handles */
+ for (i=0; i < NUMFILES; i++) {
+ sprintf(fname, "%s/file%06d", test_dir, i);
+ handle[i].fh.handle_bytes = MAX_HANDLE_SZ;
+ ret = name_to_handle_at(AT_FDCWD, fname, &handle[i].fh, &mount_id, 0);
+ if (ret < 0) {
+ perror("name_to_handle");
+ return EXIT_FAILURE;
+ }
+ }
+
+ /* unlink the files */
+ for (i=0; i < NUMFILES; i++) {
+ sprintf(fname, "%s/file%06d", test_dir, i);
+ ret = unlink(fname);
+ if (ret < 0) {
+ perror("unlink");
+ return EXIT_FAILURE;
+ }
+ }
+
+ /* sync to get log forced for unlink transactions to hit the disk */
+ sync();
+
+ /* sync once more FTW */
+ sync();
+
+ /*
+ * now drop the caches so that unlinked inodes are reclaimed and
+ * buftarg page cache is emptied so that the inode cluster has to be
+ * fetched from disk again for the open_by_handle() call.
+ */
+ ret = system("echo 3 > /proc/sys/vm/drop_caches");
+ if (ret < 0) {
+ perror("drop_caches");
+ return EXIT_FAILURE;
+ }
+
+ /*
+ * now try to open the files by the stored handles. Expecting ENOENT
+ * for all of them.
+ */
+ for (i=0; i < NUMFILES; i++) {
+ errno = 0;
+ fd = open_by_handle_at(mount_fd, &handle[i].fh, O_RDWR);
+ if (fd < 0 && (errno == ENOENT || errno == ESTALE)) {
+ continue;
+ }
+ if (fd >= 0) {
+ printf("open_by_handle(%d) opened an unlinked file!\n", i);
+ close(fd);
+ } else
+ printf("open_by_handle(%d) returned %d incorrectly on an unlinked file!\n", i, errno);
+ failed++;
+ }
+ if (failed)
+ return EXIT_FAILURE;
+ return EXIT_SUCCESS;
+}
--
2.7.4