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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.
175 lines
3.1 KiB
C
175 lines
3.1 KiB
C
/*
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* Copyright (C) 2006 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 <unistd.h>
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#include <fcntl.h>
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#ifdef UDEV_SYNC_SUPPORT
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#include <libudev.h>
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struct udev *_udev;
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int udev_init_library_context(void)
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{
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if (_udev)
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return 1;
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if (getenv("DM_DISABLE_UDEV"))
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return 0;
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if (!(_udev = udev_new())) {
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log_error("Failed to create udev library context.");
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return 0;
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}
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if (!udev_is_running()) {
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udev_unref(_udev);
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_udev = NULL;
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return 0;
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}
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return 1;
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}
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void udev_fin_library_context(void)
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{
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if (_udev)
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udev_unref(_udev);
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_udev = NULL;
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}
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int udev_is_running(void)
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{
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struct udev_queue *udev_queue;
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int r;
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if (!_udev) {
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log_debug_activation("Udev library context not set.");
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goto bad;
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}
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if (!(udev_queue = udev_queue_new(_udev))) {
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log_debug_activation("Could not get udev state.");
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goto bad;
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}
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r = udev_queue_get_udev_is_active(udev_queue);
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udev_queue_unref(udev_queue);
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return r;
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bad:
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log_debug_activation("Assuming udev is not running.");
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return 0;
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}
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void *udev_get_library_context(void)
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{
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return _udev;
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}
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#else /* UDEV_SYNC_SUPPORT */
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int udev_init_library_context(void)
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{
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return 1;
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}
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void *udev_get_library_context(void)
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{
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return NULL;
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}
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void udev_fin_library_context(void)
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{
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}
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int udev_is_running(void)
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{
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return 0;
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}
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#endif
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int lvm_getpagesize(void)
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{
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return getpagesize();
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}
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int read_urandom(void *buf, size_t len)
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{
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int fd;
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/* FIXME: we should stat here, and handle other cases */
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/* FIXME: use common _io() routine's open/read/close */
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if ((fd = open("/dev/urandom", O_RDONLY)) < 0) {
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log_sys_error("open", "read_urandom: /dev/urandom");
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return 0;
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}
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if (read(fd, buf, len) != (ssize_t) len) {
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log_sys_error("read", "read_urandom: /dev/urandom");
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if (close(fd))
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stack;
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return 0;
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}
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if (close(fd))
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stack;
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return 1;
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}
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/*
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* Return random integer in [0,max) interval
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*
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* The loop rejects numbers that come from an "incomplete" slice of the
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* RAND_MAX space. Considering the number space [0, RAND_MAX] is divided
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* into some "max"-sized slices and at most a single smaller slice,
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* between [n*max, RAND_MAX] for suitable n, numbers from this last slice
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* are discarded because they could distort the distribution in favour of
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* smaller numbers.
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*/
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unsigned lvm_even_rand(unsigned *seed, unsigned max)
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{
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unsigned r, ret;
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do {
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r = (unsigned) rand_r(seed);
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ret = r % max;
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} while (r - ret > RAND_MAX - max);
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return ret;
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}
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int clvmd_is_running(void)
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{
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#ifdef CLVMD_PIDFILE
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return dm_daemon_is_running(CLVMD_PIDFILE);
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#else
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return 0;
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#endif
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}
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int cmirrord_is_running(void)
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{
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#ifdef CMIRRORD_PIDFILE
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return dm_daemon_is_running(CMIRRORD_PIDFILE);
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#else
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return 0;
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#endif
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}
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