[Ocfs2-test-devel] [PATCH 2/7] Discontig-bg-test: Add utility to generate file with desired extents.

[Tristan Ye]

We really need a tool to generate files with massive extents, by specifying
filesize and chunksize(chunksize here actually is the size for each extent).
As a result, we'll be able to populate a desired number of extent as expected.

It could be later used as a stress extents consumer which eats up the extents
from extent_alloc sharply.

Signed-off-by: Tristan Ye <tristan.ye at oracle.com>
---
 programs/discontig_bg_test/Makefile      |    7 +-
 programs/discontig_bg_test/gen_extents.c |  225 ++++++++++++++++++++++++++++++
 2 files changed, 230 insertions(+), 2 deletions(-)
 create mode 100755 programs/discontig_bg_test/gen_extents.c

diff --git a/programs/discontig_bg_test/Makefile b/programs/discontig_bg_test/Makefile
index 1467f39..70bb9b2 100644
--- a/programs/discontig_bg_test/Makefile
+++ b/programs/discontig_bg_test/Makefile
@@ -8,13 +8,16 @@ CFLAGS = -O2 -Wall -g $(OCFS2_CFLAGS)
 
 MPI_LINK = $(MPICC) $(CFLAGS) $(LDFLAGS) -o $@ $^
 
-SOURCES = spawn_inodes.c
+SOURCES = spawn_inodes.c gen_extents.c
 
 DIST_FILES = $(SOURCES)
 
-BIN_PROGRAMS = spawn_inodes
+BIN_PROGRAMS = spawn_inodes gen_extents
 
 spawn_inode: spawn_inodes.c
 	$(LINK) $(OCFS2_LIBS)
 
+gen_extents: gen_extents.c
+	$(LINK) $(OCFS2_LIBS)
+
 include $(TOPDIR)/Postamble.make
diff --git a/programs/discontig_bg_test/gen_extents.c b/programs/discontig_bg_test/gen_extents.c
new file mode 100755
index 0000000..8ce9ae2
--- /dev/null
+++ b/programs/discontig_bg_test/gen_extents.c
@@ -0,0 +1,225 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * gen_extents.c
+ *
+ * A simple utility to generate file with extents(one cluster for each).
+ *
+ * Copyright (C) 2010 Oracle.  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 021110-1307, USA.
+ *
+ */
+
+#define _GNU_SOURCE
+#define _XOPEN_SOURCE 500
+#define _LARGEFILE64_SOURCE
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <inttypes.h>
+#include <linux/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <limits.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+
+#define FILE_MODE               (S_IRUSR|S_IWUSR|S_IXUSR|S_IROTH|\
+				 S_IWOTH|S_IXOTH|S_IRGRP|S_IWGRP|S_IXGRP)
+
+char filename[PATH_MAX];
+unsigned long long filesize;
+unsigned long long chunksize = 32768;
+int keep = 1;
+int enable_multi_nodes;
+
+static int usage(void)
+{
+	fprintf(stdout, "gen_extents <-f path> <-l filesize> <-c chunksize> "
+		"[-k keep] [-m]\n");
+	fprintf(stdout, "Example:\n"
+		"       gen_extents -f /storage/testifle -l 1073741824 -c 4096"
+		"-k 1\n");
+
+	exit(1);
+}
+
+int parse_opts(int argc, char **argv)
+{
+	char c;
+	char hostname[256];
+
+	filesize = 0;
+	enable_multi_nodes = 0;
+
+	while (1) {
+		c = getopt(argc, argv, "f:l:c:k:mh:");
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'f':
+			strncpy(filename, optarg, PATH_MAX);
+			break;
+		case 'l':
+			filesize = atoll(optarg);
+			break;
+		case 'c':
+			chunksize = atoll(optarg);
+			break;
+		case 'k':
+			keep = atoi(optarg);
+			break;
+		case 'm':
+			enable_multi_nodes = 1;
+			break;
+		case 'h':
+			usage();
+			break;
+		default:
+			return -1;
+		}
+	}
+
+	if (!filename) {
+		fprintf(stderr, "filename is a mandatory option\n");
+		usage();
+	}
+
+	if (!filesize) {
+		fprintf(stderr, "filesize is zero? NOOP!\n");
+		exit(0);
+	}
+
+	if (!chunksize) {
+		fprintf(stderr, "chunksize is a mandartory option\n");
+		usage();
+	}
+
+	if (enable_multi_nodes) {
+		if (gethostname(hostname, 256) < 0) {
+			fprintf(stderr, "gethostname failed.\n");
+			exit(1);
+		}
+		strcat(filename, hostname);
+	}
+
+	return 0;
+}
+
+/*
+ * How to construct a file with a plenty of extents:
+ *
+ * Write 2 files by turn, one is our target file, another is
+ * a temporary one, each write is in chunk size, as a result.
+ * the desired file finially will be made up of a plenty of
+ * extents in a expected number.
+ */
+int prep_file(char *file_name, uint64_t size, uint64_t chunksize, int keep)
+{
+	int fd = -1, fdt = -1, ret = 0;
+	unsigned long long offset = 0, write_size = 0;
+	char tmp_path[PATH_MAX];
+
+	char *pattern = NULL;
+	int open_rw_flags = O_CREAT|O_RDWR|O_APPEND|O_TRUNC;
+
+	pattern = (char *)malloc(chunksize);
+
+	fd = open64(file_name, open_rw_flags, FILE_MODE);
+	if (fd < 0) {
+		ret = fd;
+		fd = errno;
+		fprintf(stderr, "create file %s failed:%d:%s\n", file_name, fd,
+			strerror(fd));
+		goto bail;
+	}
+
+	memset(pattern, 'a', chunksize);
+
+	snprintf(tmp_path, PATH_MAX, "%s-tmp-file", file_name);
+
+	fdt = open64(tmp_path, open_rw_flags, FILE_MODE);
+	if (fdt < 0) {
+		ret = fdt;
+		fdt = errno;
+		fprintf(stderr, "create file %s failed:%d:%s\n",
+			tmp_path, fdt, strerror(fdt));
+		goto bail;
+	}
+
+	if (!keep)
+		unlink(tmp_path);
+
+	while (offset < size) {
+
+		if ((offset + chunksize) > size)
+			write_size = size - offset;
+		else
+			write_size = chunksize;
+
+		ret = pwrite(fd, pattern, write_size, offset);
+		if (ret < 0) {
+			ret = errno;
+			fprintf(stderr, "pwrite on %s failed at "
+				"%llu:%d:%s\n", file_name, offset,
+				ret, strerror(ret));
+			goto bail;
+		}
+
+		ret = pwrite(fdt, pattern, write_size, offset);
+		if (ret < 0) {
+			ret = errno;
+			fprintf(stderr, "pwrite on %s failed at "
+				"%llu:%d:%s\n", tmp_path, offset,
+				ret, strerror(ret));
+			goto bail;
+		}
+
+		offset += write_size;
+	}
+
+bail:
+	if (pattern)
+		free(pattern);
+
+	if (fdt > 0)
+		close(fdt);
+
+	if (fd > 0)
+		close(fd);
+
+	return ret;
+}
+
+int main(int argc, char *argv[])
+{
+	int ret = 0;
+
+	ret = parse_opts(argc, argv);
+	if (ret) {
+		usage();
+		return ret;
+	}
+
+	ret = prep_file(filename, filesize, chunksize, keep);
+
+	return ret;
+}
-- 
1.5.5