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70 lines
1.5 KiB
C
70 lines
1.5 KiB
C
/*
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* Copyright (C) 2004 Luca Berra
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* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "lib.h"
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#include "metadata.h"
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#include "xlate.h"
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/* Lifted from <linux/raid/md_p.h> because of difficulty including it */
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#define MD_SB_MAGIC 0xa92b4efc
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#define MD_RESERVED_BYTES (64 * 1024)
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#define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512)
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#define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) \
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- MD_RESERVED_SECTORS)
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/*
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* Returns -1 on error
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*/
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int dev_is_md(struct device *dev, uint64_t *sb)
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{
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int ret = 0;
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#ifdef linux
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uint64_t size, sb_offset;
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uint32_t md_magic;
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if (!dev_get_size(dev, &size)) {
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stack;
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return -1;
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}
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if (size < MD_RESERVED_SECTORS * 2)
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return 0;
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if (!dev_open(dev)) {
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stack;
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return -1;
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}
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sb_offset = MD_NEW_SIZE_SECTORS(size) << SECTOR_SHIFT;
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/* Check if it is an md component device. */
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if (dev_read(dev, sb_offset, sizeof(uint32_t), &md_magic) &&
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(md_magic == xlate32(MD_SB_MAGIC))) {
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if (sb)
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*sb = sb_offset;
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ret = 1;
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}
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if (!dev_close(dev))
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stack;
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#endif
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return ret;
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}
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