[PATCH 1/4] src/open_by_handle: helper to test open_by_handle_at() syscall

[Amir Goldstein <amir73il@gmail.com>]

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 helper yet.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 src/Makefile         |   2 +-
 src/open_by_handle.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 146 insertions(+), 1 deletion(-)
 create mode 100644 src/open_by_handle.c

diff --git a/src/Makefile b/src/Makefile
index e62d7a9..6b38e77 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -22,7 +22,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
 	seek_copy_test t_readdir_1 t_readdir_2 fsync-tester nsexec cloner \
 	renameat2 t_getcwd e4compact test-nextquota punch-alternating \
 	attr-list-by-handle-cursor-test listxattr dio-interleaved t_dir_type \
-	dio-invalidate-cache stat_test
+	dio-invalidate-cache stat_test open_by_handle
 
 SUBDIRS =
 
diff --git a/src/open_by_handle.c b/src/open_by_handle.c
new file mode 100644
index 0000000..8f04865
--- /dev/null
+++ b/src/open_by_handle.c
@@ -0,0 +1,145 @@
+/*
+ * 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.
+ */
+
+#define TEST_UTIME
+
+#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