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/*
* Copyright (C) 2004 Luca Berra
* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser 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 "lib.h"
#include "metadata.h"
#include "xlate.h"
/* Lifted from <linux/raid/md_p.h> because of difficulty including it */
#define MD_SB_MAGIC 0xa92b4efc
#define MD_RESERVED_BYTES (64 * 1024)
#define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512)
#define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) \
- MD_RESERVED_SECTORS)
/*
* Returns -1 on error
*/
int dev_is_md(struct device *dev, uint64_t *sb)
{
int ret = 0;
#ifdef linux
uint64_t size, sb_offset;
uint32_t md_magic;
if (!dev_get_size(dev, &size)) {
stack;
return -1;
}
if (size < MD_RESERVED_SECTORS * 2)
return 0;
if (!dev_open(dev)) {
stack;
return -1;
}
sb_offset = MD_NEW_SIZE_SECTORS(size) << SECTOR_SHIFT;
/* Check if it is an md component device. */
if (dev_read(dev, sb_offset, sizeof(uint32_t), &md_magic) &&
(md_magic == xlate32(MD_SB_MAGIC))) {
if (sb)
*sb = sb_offset;
ret = 1;
}
if (!dev_close(dev))
stack;
#endif
return ret;
}
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