raid6check.c - pub/scm/linux/kernel/git/hare/mdadm - Git at Google

 /*
  * raid6check - extended consistency check for RAID-6
  *
  * Copyright (C) 2011 Piergiorgio Sartor
  *
  *
  *    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
  *
  *    Author: Piergiorgio Sartor
  *    Based on "restripe.c" from "mdadm" codebase
  */

 #include "mdadm.h"
 #include <stdint.h>
 #include <signal.h>
 #include <sys/mman.h>

 int geo_map(int block, unsigned long long stripe, int raid_disks,
 	    int level, int layout);
 void qsyndrome(uint8_t *p, uint8_t *q, uint8_t **sources, int disks, int size);
 void make_tables(void);

 /* Collect per stripe consistency information */
 void raid6_collect(int chunk_size, uint8_t *p, uint8_t *q,
 		   char *chunkP, char *chunkQ, int *results)
 {
 	int i;
 	int data_id;
 	uint8_t Px, Qx;
 	extern uint8_t raid6_gflog[];

 	for(i = 0; i < chunk_size; i++) {
 		Px = (uint8_t)chunkP[i] ^ (uint8_t)p[i];
 		Qx = (uint8_t)chunkQ[i] ^ (uint8_t)q[i];

 		if((Px != 0) && (Qx == 0))
 			results[i] = -1;

 		if((Px == 0) && (Qx != 0))
 			results[i] = -2;

 		if((Px != 0) && (Qx != 0)) {
 			data_id = (raid6_gflog[Qx] - raid6_gflog[Px]);
 			if(data_id < 0) data_id += 255;
 			results[i] = data_id;
 		}

 		if((Px == 0) && (Qx == 0))
 			results[i] = -255;
 	}
 }

 /* Try to find out if a specific disk has problems */
 int raid6_stats(int *results, int raid_disks, int chunk_size)
 {
 	int i;
 	int curr_broken_disk = -255;
 	int prev_broken_disk = -255;
 	int broken_status = 0;

 	for(i = 0; i < chunk_size; i++) {

 		if(results[i] != -255)
 			curr_broken_disk = results[i];

 		if(curr_broken_disk >= raid_disks)
 			broken_status = 2;

 		switch(broken_status) {
 		case 0:
 			if(curr_broken_disk != -255) {
 				prev_broken_disk = curr_broken_disk;
 				broken_status = 1;
 			}
 			break;

 		case 1:
 			if(curr_broken_disk != prev_broken_disk)
 				broken_status = 2;
 			break;

 		case 2:
 		default:
 			curr_broken_disk = prev_broken_disk = -65535;
 			break;
 		}
 	}

 	return curr_broken_disk;
 }

 int check_stripes(struct mdinfo *info, int *source, unsigned long long *offsets,
 		  int raid_disks, int chunk_size, int level, int layout,
 		  unsigned long long start, unsigned long long length, char *name[])
 {
 	/* read the data and p and q blocks, and check we got them right */
 	char *stripe_buf = malloc(raid_disks * chunk_size);
 	char **stripes = malloc(raid_disks * sizeof(char*));
 	char **blocks = malloc(raid_disks * sizeof(char*));
 	uint8_t *p = malloc(chunk_size);
 	uint8_t *q = malloc(chunk_size);
 	int *results = malloc(chunk_size * sizeof(int));

 	int i;
 	int diskP, diskQ;
 	int data_disks = raid_disks - 2;
 	int err = 0;
 	sighandler_t sig[3];
 	int rv;

 	extern int tables_ready;

 	if((stripe_buf == NULL) ||
 	   (stripes == NULL) ||
 	   (blocks == NULL) ||
 	   (p == NULL) ||
 	   (q == NULL) ||
 	   (results == NULL)) {
 		err = 1;
 		goto exitCheck;
 	}

 	if (!tables_ready)
 		make_tables();

 	for ( i = 0 ; i < raid_disks ; i++)
 		stripes[i] = stripe_buf + i * chunk_size;

 	while (length > 0) {
 		int disk;

 		printf("pos --> %llu\n", start);

 		if(mlockall(MCL_CURRENT | MCL_FUTURE) != 0) {
 			err = 2;
 			goto exitCheck;
 		}
 		sig[0] = signal(SIGTERM, SIG_IGN);
 		sig[1] = signal(SIGINT, SIG_IGN);
 		sig[2] = signal(SIGQUIT, SIG_IGN);
 		rv = sysfs_set_num(info, NULL, "suspend_lo", start * chunk_size * data_disks);
 		rv |= sysfs_set_num(info, NULL, "suspend_hi", (start + 1) * chunk_size * data_disks);
 		for (i = 0 ; i < raid_disks ; i++) {
 			lseek64(source[i], offsets[i] + start * chunk_size, 0);
 			read(source[i], stripes[i], chunk_size);
 		}
 		rv |= sysfs_set_num(info, NULL, "suspend_lo", 0x7FFFFFFFFFFFFFFFULL);
 		rv |= sysfs_set_num(info, NULL, "suspend_hi", 0);
 		rv |= sysfs_set_num(info, NULL, "suspend_lo", 0);
 		signal(SIGQUIT, sig[2]);
 		signal(SIGINT, sig[1]);
 		signal(SIGTERM, sig[0]);
 		if(munlockall() != 0) {
 			err = 3;
 			goto exitCheck;
 		}

 		if(rv != 0) {
 			err = rv * 256;
 			goto exitCheck;
 		}

 		for (i = 0 ; i < data_disks ; i++) {
 			int disk = geo_map(i, start, raid_disks, level, layout);
 			blocks[i] = stripes[disk];
 			printf("%d->%d\n", i, disk);
 		}

 		qsyndrome(p, q, (uint8_t**)blocks, data_disks, chunk_size);
 		diskP = geo_map(-1, start, raid_disks, level, layout);
 		if (memcmp(p, stripes[diskP], chunk_size) != 0) {
 			printf("P(%d) wrong at %llu\n", diskP, start);
 		}
 		diskQ = geo_map(-2, start, raid_disks, level, layout);
 		if (memcmp(q, stripes[diskQ], chunk_size) != 0) {
 			printf("Q(%d) wrong at %llu\n", diskQ, start);
 		}
 		raid6_collect(chunk_size, p, q, stripes[diskP], stripes[diskQ], results);
 		disk = raid6_stats(results, raid_disks, chunk_size);

 		if(disk >= -2) {
 			disk = geo_map(disk, start, raid_disks, level, layout);
 		}
 		if(disk >= 0) {
 			printf("Error detected at %llu: possible failed disk slot: %d --> %s\n",
 				start, disk, name[disk]);
 		}
 		if(disk == -65535) {
 			printf("Error detected at %llu: disk slot unknown\n", start);
 		}

 		length--;
 		start++;
 	}

 exitCheck:

 	free(stripe_buf);
 	free(stripes);
 	free(blocks);
 	free(p);
 	free(q);
 	free(results);

 	return err;
 }

 unsigned long long getnum(char *str, char **err)
 {
 	char *e;
 	unsigned long long rv = strtoull(str, &e, 10);
 	if (e==str || *e) {
 		*err = str;
 		return 0;
 	}
 	return rv;
 }

 int main(int argc, char *argv[])
 {
 	/* md_device start length */
 	int *fds = NULL;
 	char *buf = NULL;
 	char **disk_name = NULL;
 	unsigned long long *offsets = NULL;
 	int raid_disks = 0;
 	int active_disks;
 	int chunk_size = 0;
 	int layout = -1;
 	int level = 6;
 	unsigned long long start, length;
 	int i;
 	int mdfd;
 	struct mdinfo *info = NULL, *comp = NULL;
 	char *err = NULL;
 	int exit_err = 0;
 	int close_flag = 0;
 	char *prg = strrchr(argv[0], '/');

 	if (prg == NULL)
 		prg = argv[0];
 	else
 		prg++;

 	if (argc < 4) {
 		fprintf(stderr, "Usage: %s md_device start_stripe length_stripes\n", prg);
 		exit_err = 1;
 		goto exitHere;
 	}

 	mdfd = open(argv[1], O_RDONLY);
 	if(mdfd < 0) {
 		perror(argv[1]);
 		fprintf(stderr,"%s: cannot open %s\n", prg, argv[1]);
 		exit_err = 2;
 		goto exitHere;
 	}

 	info = sysfs_read(mdfd, -1,
 			  GET_LEVEL|
 			  GET_LAYOUT|
 			  GET_DISKS|
 			  GET_DEGRADED |
 			  GET_COMPONENT|
 			  GET_CHUNK|
 			  GET_DEVS|
 			  GET_OFFSET|
 			  GET_SIZE);

 	if(info == NULL) {
 		fprintf(stderr, "%s: Error reading sysfs information of %s\n", prg, argv[1]);
 		exit_err = 9;
 		goto exitHere;
 	}

 	if(info->array.level != level) {
 		fprintf(stderr, "%s: %s not a RAID-6\n", prg, argv[1]);
 		exit_err = 3;
 		goto exitHere;
 	}

 	if(info->array.failed_disks > 0) {
 		fprintf(stderr, "%s: %s degraded array\n", prg, argv[1]);
 		exit_err = 8;
 		goto exitHere;
 	}

 	printf("layout: %d\n", info->array.layout);
 	printf("disks: %d\n", info->array.raid_disks);
 	printf("component size: %llu\n", info->component_size * 512);
 	printf("total stripes: %llu\n", (info->component_size * 512) / info->array.chunk_size);
 	printf("chunk size: %d\n", info->array.chunk_size);
 	printf("\n");

 	comp = info->devs;
 	for(i = 0, active_disks = 0; active_disks < info->array.raid_disks; i++) {
 		printf("disk: %d - offset: %llu - size: %llu - name: %s - slot: %d\n",
 			i, comp->data_offset * 512, comp->component_size * 512,
 			map_dev(comp->disk.major, comp->disk.minor, 0),
 			comp->disk.raid_disk);
 		if(comp->disk.raid_disk >= 0)
 			active_disks++;
 		comp = comp->next;
 	}
 	printf("\n");

 	close(mdfd);

 	raid_disks = info->array.raid_disks;
 	chunk_size = info->array.chunk_size;
 	layout = info->array.layout;
 	start = getnum(argv[2], &err);
 	length = getnum(argv[3], &err);

 	if (err) {
 		fprintf(stderr, "%s: Bad number: %s\n", prg, err);
 		exit_err = 4;
 		goto exitHere;
 	}

 	if(start > ((info->component_size * 512) / chunk_size)) {
 		start = (info->component_size * 512) / chunk_size;
 		fprintf(stderr, "%s: start beyond disks size\n", prg);
 	}

 	if((length == 0) ||
 	   ((length + start) > ((info->component_size * 512) / chunk_size))) {
 		length = (info->component_size * 512) / chunk_size - start;
 	}

 	disk_name = malloc(raid_disks * sizeof(*disk_name));
 	fds = malloc(raid_disks * sizeof(*fds));
 	offsets = malloc(raid_disks * sizeof(*offsets));
 	buf = malloc(raid_disks * chunk_size);

 	if((disk_name == NULL) ||
 	   (fds == NULL) ||
 	   (offsets == NULL) ||
 	   (buf == NULL)) {
 		fprintf(stderr, "%s: allocation fail\n", prg);
 		exit_err = 5;
 		goto exitHere;
 	}

 	memset(offsets, 0, raid_disks * sizeof(*offsets));
 	for(i=0; i<raid_disks; i++) {
 		fds[i] = -1;
 	}
 	close_flag = 1;

 	comp = info->devs;
 	for (i=0, active_disks=0; active_disks<raid_disks; i++) {
 		int disk_slot = comp->disk.raid_disk;
 		if(disk_slot >= 0) {
 			disk_name[disk_slot] = map_dev(comp->disk.major, comp->disk.minor, 0);
 			offsets[disk_slot] = comp->data_offset * 512;
 			fds[disk_slot] = open(disk_name[disk_slot], O_RDWR);
 			if (fds[disk_slot] < 0) {
 				perror(disk_name[disk_slot]);
 				fprintf(stderr,"%s: cannot open %s\n", prg, disk_name[disk_slot]);
 				exit_err = 6;
 				goto exitHere;
 			}
 			active_disks++;
 		}
 		comp = comp->next;
 	}

 	int rv = check_stripes(info, fds, offsets,
 			       raid_disks, chunk_size, level, layout,
 			       start, length, disk_name);
 	if (rv != 0) {
 		fprintf(stderr,
 			"%s: check_stripes returned %d\n", prg, rv);
 		exit_err = 7;
 		goto exitHere;
 	}

 exitHere:

 	if (close_flag)
 		for(i = 0; i < raid_disks; i++)
 			close(fds[i]);

 	free(disk_name);
 	free(fds);
 	free(offsets);
 	free(buf);

 	exit(exit_err);
 }
	/*
	* raid6check - extended consistency check for RAID-6
	*
	* Copyright (C) 2011 Piergiorgio Sartor
	*
	*
	* 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
	*
	* Author: Piergiorgio Sartor
	* Based on "restripe.c" from "mdadm" codebase
	*/

	#include "mdadm.h"
	#include <stdint.h>
	#include <signal.h>
	#include <sys/mman.h>

	int geo_map(int block, unsigned long long stripe, int raid_disks,
	int level, int layout);
	void qsyndrome(uint8_t p, uint8_t q, uint8_t **sources, int disks, int size);
	void make_tables(void);

	/* Collect per stripe consistency information */
	void raid6_collect(int chunk_size, uint8_t p, uint8_t q,
	char chunkP, char chunkQ, int *results)
	{
	int i;
	int data_id;
	uint8_t Px, Qx;
	extern uint8_t raid6_gflog[];

	for(i = 0; i < chunk_size; i++) {
	Px = (uint8_t)chunkP[i] ^ (uint8_t)p[i];
	Qx = (uint8_t)chunkQ[i] ^ (uint8_t)q[i];

	if((Px != 0) && (Qx == 0))
	results[i] = -1;

	if((Px == 0) && (Qx != 0))
	results[i] = -2;

	if((Px != 0) && (Qx != 0)) {
	data_id = (raid6_gflog[Qx] - raid6_gflog[Px]);
	if(data_id < 0) data_id += 255;
	results[i] = data_id;
	}

	if((Px == 0) && (Qx == 0))
	results[i] = -255;
	}
	}

	/* Try to find out if a specific disk has problems */
	int raid6_stats(int *results, int raid_disks, int chunk_size)
	{
	int i;
	int curr_broken_disk = -255;
	int prev_broken_disk = -255;
	int broken_status = 0;

	for(i = 0; i < chunk_size; i++) {

	if(results[i] != -255)
	curr_broken_disk = results[i];

	if(curr_broken_disk >= raid_disks)
	broken_status = 2;

	switch(broken_status) {
	case 0:
	if(curr_broken_disk != -255) {
	prev_broken_disk = curr_broken_disk;
	broken_status = 1;
	}
	break;

	case 1:
	if(curr_broken_disk != prev_broken_disk)
	broken_status = 2;
	break;

	case 2:
	default:
	curr_broken_disk = prev_broken_disk = -65535;
	break;
	}
	}

	return curr_broken_disk;
	}

	int check_stripes(struct mdinfo info, int source, unsigned long long *offsets,
	int raid_disks, int chunk_size, int level, int layout,
	unsigned long long start, unsigned long long length, char *name[])
	{
	/* read the data and p and q blocks, and check we got them right */
	char stripe_buf = malloc(raid_disks chunk_size);
	char *stripes = malloc(raid_disks sizeof(char*));
	char *blocks = malloc(raid_disks sizeof(char*));
	uint8_t *p = malloc(chunk_size);
	uint8_t *q = malloc(chunk_size);
	int results = malloc(chunk_size sizeof(int));

	int i;
	int diskP, diskQ;
	int data_disks = raid_disks - 2;
	int err = 0;
	sighandler_t sig[3];
	int rv;

	extern int tables_ready;

	if((stripe_buf == NULL) \|\|
	(stripes == NULL) \|\|
	(blocks == NULL) \|\|
	(p == NULL) \|\|
	(q == NULL) \|\|
	(results == NULL)) {
	err = 1;
	goto exitCheck;
	}

	if (!tables_ready)
	make_tables();

	for ( i = 0 ; i < raid_disks ; i++)
	stripes[i] = stripe_buf + i * chunk_size;

	while (length > 0) {
	int disk;

	printf("pos --> %llu\n", start);

	if(mlockall(MCL_CURRENT \| MCL_FUTURE) != 0) {
	err = 2;
	goto exitCheck;
	}
	sig[0] = signal(SIGTERM, SIG_IGN);
	sig[1] = signal(SIGINT, SIG_IGN);
	sig[2] = signal(SIGQUIT, SIG_IGN);
	rv = sysfs_set_num(info, NULL, "suspend_lo", start * chunk_size * data_disks);
	rv \|= sysfs_set_num(info, NULL, "suspend_hi", (start + 1) * chunk_size * data_disks);
	for (i = 0 ; i < raid_disks ; i++) {
	lseek64(source[i], offsets[i] + start * chunk_size, 0);
	read(source[i], stripes[i], chunk_size);
	}
	rv \|= sysfs_set_num(info, NULL, "suspend_lo", 0x7FFFFFFFFFFFFFFFULL);
	rv \|= sysfs_set_num(info, NULL, "suspend_hi", 0);
	rv \|= sysfs_set_num(info, NULL, "suspend_lo", 0);
	signal(SIGQUIT, sig[2]);
	signal(SIGINT, sig[1]);
	signal(SIGTERM, sig[0]);
	if(munlockall() != 0) {
	err = 3;
	goto exitCheck;
	}

	if(rv != 0) {
	err = rv * 256;
	goto exitCheck;
	}

	for (i = 0 ; i < data_disks ; i++) {
	int disk = geo_map(i, start, raid_disks, level, layout);
	blocks[i] = stripes[disk];
	printf("%d->%d\n", i, disk);
	}

	qsyndrome(p, q, (uint8_t**)blocks, data_disks, chunk_size);
	diskP = geo_map(-1, start, raid_disks, level, layout);
	if (memcmp(p, stripes[diskP], chunk_size) != 0) {
	printf("P(%d) wrong at %llu\n", diskP, start);
	}
	diskQ = geo_map(-2, start, raid_disks, level, layout);
	if (memcmp(q, stripes[diskQ], chunk_size) != 0) {
	printf("Q(%d) wrong at %llu\n", diskQ, start);
	}
	raid6_collect(chunk_size, p, q, stripes[diskP], stripes[diskQ], results);
	disk = raid6_stats(results, raid_disks, chunk_size);

	if(disk >= -2) {
	disk = geo_map(disk, start, raid_disks, level, layout);
	}
	if(disk >= 0) {
	printf("Error detected at %llu: possible failed disk slot: %d --> %s\n",
	start, disk, name[disk]);
	}
	if(disk == -65535) {
	printf("Error detected at %llu: disk slot unknown\n", start);
	}

	length--;
	start++;
	}

	exitCheck:

	free(stripe_buf);
	free(stripes);
	free(blocks);
	free(p);
	free(q);
	free(results);

	return err;
	}

	unsigned long long getnum(char str, char *err)
	{
	char *e;
	unsigned long long rv = strtoull(str, &e, 10);
	if (e==str \|\| *e) {
	*err = str;
	return 0;
	}
	return rv;
	}

	int main(int argc, char *argv[])
	{
	/* md_device start length */
	int *fds = NULL;
	char *buf = NULL;
	char **disk_name = NULL;
	unsigned long long *offsets = NULL;
	int raid_disks = 0;
	int active_disks;
	int chunk_size = 0;
	int layout = -1;
	int level = 6;
	unsigned long long start, length;
	int i;
	int mdfd;
	struct mdinfo info = NULL, comp = NULL;
	char *err = NULL;
	int exit_err = 0;
	int close_flag = 0;
	char *prg = strrchr(argv[0], '/');

	if (prg == NULL)
	prg = argv[0];
	else
	prg++;

	if (argc < 4) {
	fprintf(stderr, "Usage: %s md_device start_stripe length_stripes\n", prg);
	exit_err = 1;
	goto exitHere;
	}

	mdfd = open(argv[1], O_RDONLY);
	if(mdfd < 0) {
	perror(argv[1]);
	fprintf(stderr,"%s: cannot open %s\n", prg, argv[1]);
	exit_err = 2;
	goto exitHere;
	}

	info = sysfs_read(mdfd, -1,
	GET_LEVEL\|
	GET_LAYOUT\|
	GET_DISKS\|
	GET_DEGRADED \|
	GET_COMPONENT\|
	GET_CHUNK\|
	GET_DEVS\|
	GET_OFFSET\|
	GET_SIZE);

	if(info == NULL) {
	fprintf(stderr, "%s: Error reading sysfs information of %s\n", prg, argv[1]);
	exit_err = 9;
	goto exitHere;
	}

	if(info->array.level != level) {
	fprintf(stderr, "%s: %s not a RAID-6\n", prg, argv[1]);
	exit_err = 3;
	goto exitHere;
	}

	if(info->array.failed_disks > 0) {
	fprintf(stderr, "%s: %s degraded array\n", prg, argv[1]);
	exit_err = 8;
	goto exitHere;
	}

	printf("layout: %d\n", info->array.layout);
	printf("disks: %d\n", info->array.raid_disks);
	printf("component size: %llu\n", info->component_size * 512);
	printf("total stripes: %llu\n", (info->component_size * 512) / info->array.chunk_size);
	printf("chunk size: %d\n", info->array.chunk_size);
	printf("\n");

	comp = info->devs;
	for(i = 0, active_disks = 0; active_disks < info->array.raid_disks; i++) {
	printf("disk: %d - offset: %llu - size: %llu - name: %s - slot: %d\n",
	i, comp->data_offset * 512, comp->component_size * 512,
	map_dev(comp->disk.major, comp->disk.minor, 0),
	comp->disk.raid_disk);
	if(comp->disk.raid_disk >= 0)
	active_disks++;
	comp = comp->next;
	}
	printf("\n");

	close(mdfd);

	raid_disks = info->array.raid_disks;
	chunk_size = info->array.chunk_size;
	layout = info->array.layout;
	start = getnum(argv[2], &err);
	length = getnum(argv[3], &err);

	if (err) {
	fprintf(stderr, "%s: Bad number: %s\n", prg, err);
	exit_err = 4;
	goto exitHere;
	}

	if(start > ((info->component_size * 512) / chunk_size)) {
	start = (info->component_size * 512) / chunk_size;
	fprintf(stderr, "%s: start beyond disks size\n", prg);
	}

	if((length == 0) \|\|
	((length + start) > ((info->component_size * 512) / chunk_size))) {
	length = (info->component_size * 512) / chunk_size - start;
	}

	disk_name = malloc(raid_disks * sizeof(*disk_name));
	fds = malloc(raid_disks * sizeof(*fds));
	offsets = malloc(raid_disks * sizeof(*offsets));
	buf = malloc(raid_disks * chunk_size);

	if((disk_name == NULL) \|\|
	(fds == NULL) \|\|
	(offsets == NULL) \|\|
	(buf == NULL)) {
	fprintf(stderr, "%s: allocation fail\n", prg);
	exit_err = 5;
	goto exitHere;
	}

	memset(offsets, 0, raid_disks * sizeof(*offsets));
	for(i=0; i<raid_disks; i++) {
	fds[i] = -1;
	}
	close_flag = 1;

	comp = info->devs;
	for (i=0, active_disks=0; active_disks<raid_disks; i++) {
	int disk_slot = comp->disk.raid_disk;
	if(disk_slot >= 0) {
	disk_name[disk_slot] = map_dev(comp->disk.major, comp->disk.minor, 0);
	offsets[disk_slot] = comp->data_offset * 512;
	fds[disk_slot] = open(disk_name[disk_slot], O_RDWR);
	if (fds[disk_slot] < 0) {
	perror(disk_name[disk_slot]);
	fprintf(stderr,"%s: cannot open %s\n", prg, disk_name[disk_slot]);
	exit_err = 6;
	goto exitHere;
	}
	active_disks++;
	}
	comp = comp->next;
	}

	int rv = check_stripes(info, fds, offsets,
	raid_disks, chunk_size, level, layout,
	start, length, disk_name);
	if (rv != 0) {
	fprintf(stderr,
	"%s: check_stripes returned %d\n", prg, rv);
	exit_err = 7;
	goto exitHere;
	}

	exitHere:

	if (close_flag)
	for(i = 0; i < raid_disks; i++)
	close(fds[i]);

	free(disk_name);
	free(fds);
	free(offsets);
	free(buf);

	exit(exit_err);
	}