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9048565093
related to config settings:
obtain_device_info_from_udev (controls if lvm gets
a list of devices from readdir /dev or from libudev)
external_device_info_source (controls if lvm asks
libudev for device information)
. Make the obtain_device_list_from_udev setting
affect only the choice of readdir /dev vs libudev.
The setting no longer controls if udev is used for
device type checks.
. Change obtain_device_list_from_udev default to 0.
This helps avoid boot timeouts due to slow libudev
queries, avoids reported failures from
udev_enumerate_scan_devices, and avoids delays from
"device not initialized in udev database" errors.
Even without errors, for a system booting with 1024 PVs,
lvm2-pvscan times improve from about 100 sec to 15 sec,
and the pvscan command from about 64 sec to about 4 sec.
. For external_device_info_source="none", remove all
libudev device info queries, and use only lvm
native device info.
. For external_device_info_source="udev", first check
lvm native device info, then check libudev info.
. Remove sleep/retry loop when attempting libudev
queries for device info. udev info will simply
be skipped if it's not immediately available.
. Only set up a libdev connection if it will be used by
obtain_device_list_from_udev/external_device_info_source.
. For native multipath component detection, use
/etc/multipath/wwids. If a device has a wwid
matching an entry in the wwids file, then it's
considered a multipath component. This is
necessary to natively detect multipath
components when the mpath device is not set up.
77 lines
1.7 KiB
C
77 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "lib/misc/lib.h"
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#include "lib/device/dev-type.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 _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 cmd_context *cmd, struct device *dev, uint64_t *offset_found, int full)
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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 (!scan_bcache)
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return -EAGAIN;
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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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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 >> SECTOR_SHIFT))
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break;
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if (!dev_read_bytes(dev, page - SIGNATURE_SIZE, 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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if (offset_found)
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*offset_found = 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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return ret;
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}
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#endif
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