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c08c564e21
Before, we used vg_write_lock_held call to determnine the way a device is opened. Unfortunately, this opened many devices in RW mode when it was not really necessary. With the OPTIONS+="watch" rule used in the udev rules, this could fire numerous events while closing such devices (and it caused useless scans from within udev rules in return). A common bug we hit with this was with the lvremove command which was unable to remove the LV since it was being opened from within the udev rules. This patch should minimize such situations (at least with respect to LVM handling of devices). Though there's still a possibility someone will open a device 'outside' in parallel and fire the event based on the watch rule when closing a device once opened for RW.
87 lines
1.7 KiB
C
87 lines
1.7 KiB
C
/*
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* Copyright (C) 2009 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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#include "filter.h"
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#ifdef linux
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#define MAX_PAGESIZE (64 * 1024)
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#define SIGNATURE_SIZE 10
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static int
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_swap_detect_signature(const char *buf)
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{
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if (memcmp(buf, "SWAP-SPACE", 10) == 0 ||
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memcmp(buf, "SWAPSPACE2", 10) == 0)
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return 1;
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if (memcmp(buf, "S1SUSPEND", 9) == 0 ||
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memcmp(buf, "S2SUSPEND", 9) == 0 ||
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memcmp(buf, "ULSUSPEND", 9) == 0 ||
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memcmp(buf, "\xed\xc3\x02\xe9\x98\x56\xe5\x0c", 8) == 0)
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return 1;
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return 0;
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}
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int dev_is_swap(struct device *dev, uint64_t *signature)
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{
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char buf[10];
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uint64_t size;
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unsigned page;
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int ret = 0;
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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 (!dev_open_readonly(dev)) {
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stack;
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return -1;
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}
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*signature = 0;
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for (page = 0x1000; page <= MAX_PAGESIZE; page <<= 1) {
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/*
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* skip 32k pagesize since this does not seem to be supported
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*/
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if (page == 0x8000)
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continue;
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if (size < page)
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break;
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if (!dev_read(dev, page - SIGNATURE_SIZE,
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SIGNATURE_SIZE, buf)) {
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ret = -1;
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break;
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}
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if (_swap_detect_signature(buf)) {
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*signature = page - SIGNATURE_SIZE;
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ret = 1;
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break;
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}
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}
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if (!dev_close(dev))
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stack;
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return ret;
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}
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#endif
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