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lvm2/lib/device/dev-cache.h
Peter Rajnoha 8c27c52749 dev-cache: also index VGIDs and LVIDs if using persistent .cache file
If we're using persistent .cache file, we're reading this file instead
of traversing the /dev content. Fix missing indexing by VGID and LVID
here - hook this into persistent_filter_load where we populate device
cache from persistent .cache file instead of scanning /dev.

For example, inducing situation in which we warn about different device
actually used than what LVM thinks should be used based on metadata:

$ lsblk -s /dev/vg/lvol0
NAME     MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vg-lvol0 253:4    0  124M  0 lvm
`-loop1    7:1    0  128M  0 loop

$ lvmconfig --type diff

global {
	use_lvmetad=0
}
devices {
	obtain_device_list_from_udev=0
}

(obtain_device_list_from_udev=0 also means the persistent .cache file is used)

Before this patch - pvs is fine as it does the dev scan, but lvs relies
on persistent .cache file and it misses the VGID/LVID indices to check
and warn about incorrect devices used:

$ pvs
  Found duplicate PV B9gXTHkIdEIiMVwcOoT2LX3Ywh4YIHgR: using /dev/loop0 not /dev/loop1
  Using duplicate PV /dev/loop0 without holders, ignoring /dev/loop1
  WARNING: Device mismatch detected for vg/lvol0 which is accessing /dev/loop1 instead of /dev/loop0.
  PV          VG Fmt  Attr PSize   PFree
  /dev/loop0 vg lvm2 a--  124.00m    0

$ lvs
  Found duplicate PV B9gXTHkIdEIiMVwcOoT2LX3Ywh4YIHgR: using /dev/loop0 not /dev/loop1
  Using duplicate PV /dev/loop0 without holders, ignoring /dev/loop1
  LV    VG Attr       LSize
  lvol0 vg -wi-a----- 124.00m

With this patch applied - both pvs and lvs is fine - the indices are
always created correctly (lvs just an example here, other LVM commands
that rely on persistent .cache file are fixed with this patch too):

$ pvs
  Found duplicate PV B9gXTHkIdEIiMVwcOoT2LX3Ywh4YIHgR: using /dev/loop0 not /dev/loop1
  Using duplicate PV /dev/loop0 without holders, ignoring /dev/loop1
  WARNING: Device mismatch detected for vg/lvol0 which is accessing /dev/loop1 instead of /dev/loop0.
  PV          VG Fmt  Attr PSize   PFree
  /dev/loop0 vg lvm2 a--  124.00m    0

$ lvs
  Found duplicate PV B9gXTHkIdEIiMVwcOoT2LX3Ywh4YIHgR: using /dev/loop0 not /dev/loop1
  Using duplicate PV /dev/loop0 without holders, ignoring /dev/loop1
  WARNING: Device mismatch detected for vg/lvol0 which is accessing /dev/loop1 instead of /dev/loop0.
  LV    VG Attr       LSize
  lvol0 vg -wi-a----- 124.00m
2016-03-30 11:00:01 +02:00

75 lines
2.1 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_DEV_CACHE_H
#define _LVM_DEV_CACHE_H
#include "device.h"
#include "lvm-wrappers.h"
/*
* predicate for devices.
*/
struct dev_filter {
int (*passes_filter) (struct dev_filter * f, struct device * dev);
void (*destroy) (struct dev_filter * f);
void (*wipe) (struct dev_filter * f);
int (*dump) (struct dev_filter * f, int merge_existing);
void *private;
unsigned use_count;
};
int dev_cache_index_devs(void);
struct dm_list *dev_cache_get_dev_list_for_vgid(const char *vgid);
struct dm_list *dev_cache_get_dev_list_for_lvid(const char *lvid);
/*
* The global device cache.
*/
struct cmd_context;
int dev_cache_init(struct cmd_context *cmd);
int dev_cache_exit(void);
/*
* Returns number of open devices.
*/
int dev_cache_check_for_open_devices(void);
/* Trigger(1) or avoid(0) a scan */
void dev_cache_scan(int do_scan);
int dev_cache_has_scanned(void);
void dev_cache_full_scan(struct dev_filter *f);
int dev_cache_add_dir(const char *path);
int dev_cache_add_loopfile(const char *path);
__attribute__((nonnull(1)))
struct device *dev_cache_get(const char *name, struct dev_filter *f);
// TODO
struct device *dev_cache_get_by_devt(dev_t device, struct dev_filter *f);
void dev_set_preferred_name(struct dm_str_list *sl, struct device *dev);
/*
* Object for iterating through the cache.
*/
struct dev_iter;
struct dev_iter *dev_iter_create(struct dev_filter *f, int dev_scan);
void dev_iter_destroy(struct dev_iter *iter);
struct device *dev_iter_get(struct dev_iter *iter);
void dev_reset_error_count(struct cmd_context *cmd);
#endif