useful simple program for creating holes when want

to create lots of extents
Merge of master-melb:xfs-cmds:23185a by kenmcd.

  Add makeextents

src/Makefile

@@ -37,7 +37,7 @@ TARGETS = dirstress fill fill2 getpagesize holes lstat64 \
 	nametest permname randholes runas truncfile usemem \
 	mmapcat append_reader append_writer dirperf metaperf \
 	devzero feature alloc fault fstest t_access_root \
-	godown resvtest writemod
+	godown resvtest writemod makeextents
 
 LINUX_TARGETS = loggen xfsctl bstat t_mtab getdevicesize
 

src/makeextents.c

@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) 2000-2004 Silicon Graphics, Inc.  All Rights Reserved.
+ * 
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * 
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like.  Any license provided herein, whether implied or
+ * otherwise, applies only to this software file.  Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ * 
+ * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA  94043, or:
+ * 
+ * http://www.sgi.com 
+ * 
+ * For further information regarding this notice, see: 
+ * 
+ * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
+ */
+
+/*
+ * Write a bunch of holes to create a bunch of extents.
+ */
+ 
+#include "global.h"
+
+char *progname;
+__uint64_t num_holes = 1000;
+int verbose_opt = 0;
+char *filename;
+int status_num = 100;
+int wsync;
+int preserve;
+unsigned int blocksize;
+__uint64_t fileoffset;
+
+void
+usage(void)
+{
+	fprintf(stderr, "%s [-b blocksize] [-n num-holes] [-s status-num]"
+			" [-o start-offset] [-vwp] file\n", progname);
+	exit(1);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int c;
+	int fd;
+	int oflags;
+	__uint64_t i;
+	__uint64_t offset;
+	int blocksize = 512;
+	unsigned char *buffer = NULL;
+
+
+	progname = argv[0];
+
+	while ((c = getopt(argc, argv, "b:n:o:ps:vw")) != -1) {
+		switch (c) {
+		case 'b':
+			blocksize = atoi(optarg);
+			break;
+		case 'n':
+			num_holes = atoll(optarg);
+			break;
+		case 'v':
+			verbose_opt = 1;
+			break;
+		case 'w':
+			wsync = 1;
+			break;
+		case 'p':
+			preserve = 1;
+			break;
+		case 's':
+			status_num = atoi(optarg);
+			break;
+		case 'o':
+			fileoffset = strtoull(optarg, NULL, 16);
+			break;
+		case '?':
+			usage();
+		}
+	}
+	if (optind == argc-1)
+		filename = argv[optind];
+	else
+		usage();
+
+	buffer = malloc(blocksize);
+	if (buffer == NULL) {
+	    fprintf(stderr, "%s: blocksize to big to allocate buffer\n", progname);
+	    return 1;
+	}
+
+        oflags = O_RDWR | O_CREAT;
+	oflags |=   (preserve ? 0 : O_TRUNC) |
+		    (wsync ? O_SYNC : 0);
+        
+	if ((fd = open(filename, oflags, 0666)) < 0) {
+		perror("open");
+		return 1;
+	}
+
+	for (i = 0; i < num_holes; i++) {
+
+		offset = i * 128 * 1024 + fileoffset;
+
+		if (lseek64(fd, offset, SEEK_SET) < 0) {
+			perror("lseek");
+			return 1;
+		}
+
+		if (write(fd, buffer, blocksize) < blocksize) {
+			perror("write");
+			return 1;
+		}
+
+		if (verbose_opt && ((i+1) % status_num == 0)) {
+			printf("seeked and wrote %llu times\n", i+1);
+		}
+	}
+
+	close(fd);
+
+	return 0;
+}