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lvm2/lib/device/device_id.h
David Teigland 9048565093 devices: rework libudev usage
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.
2021-07-13 11:11:23 -05:00

58 lines
2.6 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2007 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _LVM_DEVICE_ID_H
#define _LVM_DEVICE_ID_H
void free_du(struct dev_use *du);
void free_dus(struct dm_list *list);
void free_did(struct dev_id *did);
void free_dids(struct dm_list *list);
const char *idtype_to_str(uint16_t idtype);
uint16_t idtype_from_str(const char *str);
const char *dev_idtype_for_metadata(struct cmd_context *cmd, struct device *dev);
const char *dev_idname_for_metadata(struct cmd_context *cmd, struct device *dev);
int device_ids_use_devname(struct cmd_context *cmd);
int device_ids_read(struct cmd_context *cmd);
int device_ids_write(struct cmd_context *cmd);
int device_id_add(struct cmd_context *cmd, struct device *dev, const char *pvid,
const char *idtype_arg, const char *id_arg);
void device_id_pvremove(struct cmd_context *cmd, struct device *dev);
void device_ids_match(struct cmd_context *cmd);
int device_ids_match_dev(struct cmd_context *cmd, struct device *dev);
void device_ids_validate(struct cmd_context *cmd, struct dm_list *scanned_devs, int *device_ids_invalid, int noupdate);
int device_ids_version_unchanged(struct cmd_context *cmd);
void device_ids_find_renamed_devs(struct cmd_context *cmd, struct dm_list *dev_list, int *search_count, int noupdate);
const char *device_id_system_read(struct cmd_context *cmd, struct device *dev, uint16_t idtype);
struct dev_use *get_du_for_dev(struct cmd_context *cmd, struct device *dev);
struct dev_use *get_du_for_pvid(struct cmd_context *cmd, const char *pvid);
char *devices_file_version(void);
int devices_file_exists(struct cmd_context *cmd);
int devices_file_touch(struct cmd_context *cmd);
int lock_devices_file(struct cmd_context *cmd, int mode);
int lock_devices_file_try(struct cmd_context *cmd, int mode, int *held);
void unlock_devices_file(struct cmd_context *cmd);
void devices_file_init(struct cmd_context *cmd);
void devices_file_exit(struct cmd_context *cmd);
void unlink_searched_devnames(struct cmd_context *cmd);
int read_sys_block(struct cmd_context *cmd, struct device *dev, const char *suffix, char *sysbuf, int sysbufsize);
#endif