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lvm2/lib/metadata/pv.c
David Teigland 83fe6e720f device usage based on devices file
The LVM devices file lists devices that lvm can use.  The default
file is /etc/lvm/devices/system.devices, and the lvmdevices(8)
command is used to add or remove device entries.  If the file
does not exist, or if lvm.conf includes use_devicesfile=0, then
lvm will not use a devices file.  When the devices file is in use,
the regex filter is not used, and the filter settings in lvm.conf
or on the command line are ignored.

LVM records devices in the devices file using hardware-specific
IDs, such as the WWID, and attempts to use subsystem-specific
IDs for virtual device types.  These device IDs are also written
in the VG metadata.  When no hardware or virtual ID is available,
lvm falls back using the unstable device name as the device ID.
When devnames are used, lvm performs extra scanning to find
devices if their devname changes, e.g. after reboot.

When proper device IDs are used, an lvm command will not look
at devices outside the devices file, but when devnames are used
as a fallback, lvm will scan devices outside the devices file
to locate PVs on renamed devices.  A config setting
search_for_devnames can be used to control the scanning for
renamed devname entries.

Related to the devices file, the new command option
--devices <devnames> allows a list of devices to be specified for
the command to use, overriding the devices file.  The listed
devices act as a sort of devices file in terms of limiting which
devices lvm will see and use.  Devices that are not listed will
appear to be missing to the lvm command.

Multiple devices files can be kept in /etc/lvm/devices, which
allows lvm to be used with different sets of devices, e.g.
system devices do not need to be exposed to a specific application,
and the application can use lvm on its own set of devices that are
not exposed to the system.  The option --devicesfile <filename> is
used to select the devices file to use with the command.  Without
the option set, the default system devices file is used.

Setting --devicesfile "" causes lvm to not use a devices file.

An existing, empty devices file means lvm will see no devices.

The new command vgimportdevices adds PVs from a VG to the devices
file and updates the VG metadata to include the device IDs.
vgimportdevices -a will import all VGs into the system devices file.

LVM commands run by dmeventd not use a devices file by default,
and will look at all devices on the system.  A devices file can
be created for dmeventd (/etc/lvm/devices/dmeventd.devices)  If
this file exists, lvm commands run by dmeventd will use it.

Internal implementaion:

- device_ids_read - read the devices file
  . add struct dev_use (du) to cmd->use_devices for each devices file entry
- dev_cache_scan - get /dev entries
  . add struct device (dev) to dev_cache for each device on the system
- device_ids_match - match devices file entries to /dev entries
  . match each du on cmd->use_devices to a dev in dev_cache, using device ID
  . on match, set du->dev, dev->id, dev->flags MATCHED_USE_ID
- label_scan - read lvm headers and metadata from devices
  . filters are applied, those that do not need data from the device
  . filter-deviceid skips devs without MATCHED_USE_ID, i.e.
    skips /dev entries that are not listed in the devices file
  . read lvm label from dev
  . filters are applied, those that use data from the device
  . read lvm metadata from dev
  . add info/vginfo structs for PVs/VGs (info is "lvmcache")
- device_ids_find_renamed_devs - handle devices with unstable devname ID
  where devname changed
  . this step only needed when devs do not have proper device IDs,
    and their dev names change, e.g. after reboot sdb becomes sdc.
  . detect incorrect match because PVID in the devices file entry
    does not match the PVID found when the device was read above
  . undo incorrect match between du and dev above
  . search system devices for new location of PVID
  . update devices file with new devnames for PVIDs on renamed devices
  . label_scan the renamed devs
- continue with command processing
2021-02-23 16:43:32 -06:00

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9.9 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2010 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
*/
#include "lib/misc/lib.h"
#include "lib/metadata/metadata.h"
#include "lib/cache/lvmcache.h"
/*
* FIXME: Check for valid handle before dereferencing field or log error?
*/
#define pv_field(handle, field) ((handle)->field)
char *pv_fmt_dup(const struct physical_volume *pv)
{
if (!pv->fmt)
return NULL;
return dm_pool_strdup(pv->vg->vgmem, pv->fmt->name);
}
char *pv_name_dup(struct dm_pool *mem, const struct physical_volume *pv)
{
return dm_pool_strdup(mem ? mem : pv->vg->vgmem, dev_name(pv->dev));
}
/*
* Gets/Sets for external LVM library
*/
struct id pv_id(const struct physical_volume *pv)
{
return pv_field(pv, id);
}
char *pv_uuid_dup(struct dm_pool *mem, const struct physical_volume *pv)
{
return id_format_and_copy(mem ? mem : pv->vg->vgmem, &pv->id);
}
char *pv_tags_dup(const struct physical_volume *pv)
{
return tags_format_and_copy(pv->vg->vgmem, &pv->tags);
}
char *pv_deviceid_dup(struct dm_pool *mem, const struct physical_volume *pv)
{
if (!pv->device_id)
return NULL;
return dm_pool_strdup(mem, pv->device_id);
}
char *pv_deviceidtype_dup(struct dm_pool *mem, const struct physical_volume *pv)
{
if (!pv->device_id_type)
return NULL;
return dm_pool_strdup(mem, pv->device_id_type);
}
const struct format_type *pv_format_type(const struct physical_volume *pv)
{
return pv_field(pv, fmt);
}
struct id pv_vgid(const struct physical_volume *pv)
{
return pv_field(pv, vgid);
}
struct device *pv_dev(const struct physical_volume *pv)
{
return pv_field(pv, dev);
}
const char *pv_vg_name(const struct physical_volume *pv)
{
/* Avoid exposing internal orphan names to users */
return (!is_orphan(pv)) ? pv_field(pv, vg_name) : "";
}
const char *pv_dev_name(const struct physical_volume *pv)
{
return dev_name(pv_dev(pv));
}
uint64_t pv_size(const struct physical_volume *pv)
{
return pv_field(pv, size);
}
uint64_t pv_dev_size(const struct physical_volume *pv)
{
uint64_t size;
if (!dev_get_size(pv->dev, &size))
size = 0;
return size;
}
uint64_t pv_size_field(const struct physical_volume *pv)
{
uint64_t size;
if (!pv->pe_count)
size = pv->size;
else
size = (uint64_t) pv->pe_count * pv->pe_size;
return size;
}
uint64_t pv_free(const struct physical_volume *pv)
{
uint64_t freespace;
if (!pv->vg || is_orphan_vg(pv->vg->name))
freespace = pv->size;
else
freespace = (uint64_t)
(pv->pe_count - pv->pe_alloc_count) * pv->pe_size;
return freespace;
}
uint64_t pv_status(const struct physical_volume *pv)
{
return pv_field(pv, status);
}
uint32_t pv_pe_size(const struct physical_volume *pv)
{
return pv_field(pv, pe_size);
}
uint64_t pv_ba_start(const struct physical_volume *pv)
{
return pv_field(pv, ba_start);
}
uint64_t pv_ba_size(const struct physical_volume *pv)
{
return pv_field(pv, ba_size);
}
uint64_t pv_pe_start(const struct physical_volume *pv)
{
return pv_field(pv, pe_start);
}
uint32_t pv_pe_count(const struct physical_volume *pv)
{
return pv_field(pv, pe_count);
}
uint32_t pv_pe_alloc_count(const struct physical_volume *pv)
{
return pv_field(pv, pe_alloc_count);
}
uint32_t pv_mda_count(const struct physical_volume *pv)
{
struct lvmcache_info *info;
info = lvmcache_info_from_pvid((const char *)&pv->id.uuid, pv->dev, 0);
return info ? lvmcache_mda_count(info) : UINT64_C(0);
}
static int _count_unignored(struct metadata_area *mda, void *baton)
{
uint32_t *count = baton;
if (!mda_is_ignored(mda))
(*count) ++;
return 1;
}
uint32_t pv_mda_used_count(const struct physical_volume *pv)
{
struct lvmcache_info *info;
uint32_t used_count=0;
info = lvmcache_info_from_pvid((const char *)&pv->id.uuid, pv->dev, 0);
if (!info)
return 0;
lvmcache_foreach_mda(info, _count_unignored, &used_count);
return used_count;
}
/**
* is_orphan - Determine whether a pv is an orphan based on its vg_name
* @pv: handle to the physical volume
*/
int is_orphan(const struct physical_volume *pv)
{
return is_orphan_vg(pv_field(pv, vg_name));
}
/**
* is_pv - Determine whether a pv is a real pv or dummy one
* @pv: handle to device
*/
int is_pv(const struct physical_volume *pv)
{
return (pv_field(pv, vg_name) ? 1 : 0);
}
int is_missing_pv(const struct physical_volume *pv)
{
return pv_field(pv, status) & MISSING_PV ? 1 : 0;
}
int is_used_pv(const struct physical_volume *pv)
{
struct lvmcache_info *info;
uint32_t ext_flags;
if (!pv->fmt)
return 0;
if (!is_orphan(pv))
return 1;
if (!(pv->fmt->features & FMT_PV_FLAGS))
return 0;
if (!(info = lvmcache_info_from_pvid((const char *)&pv->id, pv->dev, 0))) {
log_error("Failed to find cached info for PV %s.", pv_dev_name(pv));
return -1;
}
ext_flags = lvmcache_ext_flags(info);
return ext_flags & PV_EXT_USED ? 1 : 0;
}
char *pv_attr_dup(struct dm_pool *mem, const struct physical_volume *pv)
{
char *repstr;
int used = is_used_pv(pv);
int duplicate = lvmcache_dev_is_unused_duplicate(pv->dev);
if (!(repstr = dm_pool_zalloc(mem, 4))) {
log_error("dm_pool_alloc failed");
return NULL;
}
/*
* An allocatable PV is always used, so we don't need to show 'u'.
*/
if (duplicate)
repstr[0] = 'd';
else if (pv->status & ALLOCATABLE_PV)
repstr[0] = 'a';
else if (used > 0)
repstr[0] = 'u';
else
repstr[0] = '-';
repstr[1] = (pv->status & EXPORTED_VG) ? 'x' : '-';
repstr[2] = (pv->status & MISSING_PV) ? 'm' : '-';
return repstr;
}
uint64_t pv_mda_size(const struct physical_volume *pv)
{
struct lvmcache_info *info;
uint64_t min_mda_size = 0;
const char *pvid = (const char *)(&pv->id.uuid);
/* PVs could have 2 mdas of different sizes (rounding effect) */
if ((info = lvmcache_info_from_pvid(pvid, pv->dev, 0)))
min_mda_size = lvmcache_smallest_mda_size(info);
return min_mda_size;
}
static int _pv_mda_free(struct metadata_area *mda, void *baton)
{
uint64_t mda_free;
uint64_t *freespace = baton;
if (!mda->ops->mda_free_sectors)
return 1;
mda_free = mda->ops->mda_free_sectors(mda);
if (mda_free < *freespace)
*freespace = mda_free;
return 1;
}
uint64_t lvmcache_info_mda_free(struct lvmcache_info *info)
{
uint64_t freespace = UINT64_MAX;
if (info)
lvmcache_foreach_mda(info, _pv_mda_free, &freespace);
if (freespace == UINT64_MAX)
freespace = UINT64_C(0);
return freespace;
}
uint64_t pv_mda_free(const struct physical_volume *pv)
{
const char *pvid = (const char *)&pv->id.uuid;
struct lvmcache_info *info;
if ((info = lvmcache_info_from_pvid(pvid, pv->dev, 0)))
return lvmcache_info_mda_free(info);
return 0;
}
uint64_t pv_used(const struct physical_volume *pv)
{
uint64_t used;
if (!pv->pe_count)
used = 0LL;
else
used = (uint64_t) pv->pe_alloc_count * pv->pe_size;
return used;
}
struct _pv_mda_set_ignored_baton {
unsigned mda_ignored;
struct dm_list *mdas_in_use, *mdas_ignored, *mdas_to_change;
};
static int _pv_mda_set_ignored_one(struct metadata_area *mda, void *baton)
{
struct _pv_mda_set_ignored_baton *b = baton;
struct metadata_area *vg_mda, *tmda;
if (mda_is_ignored(mda) && !b->mda_ignored) {
/* Changing an ignored mda to one in_use requires moving it */
dm_list_iterate_items_safe(vg_mda, tmda, b->mdas_ignored)
if (mda_locns_match(mda, vg_mda)) {
mda_set_ignored(vg_mda, b->mda_ignored);
dm_list_move(b->mdas_in_use, &vg_mda->list);
}
}
dm_list_iterate_items_safe(vg_mda, tmda, b->mdas_in_use)
if (mda_locns_match(mda, vg_mda))
/* Don't move mda: needs writing to disk. */
mda_set_ignored(vg_mda, b->mda_ignored);
mda_set_ignored(mda, b->mda_ignored);
return 1;
}
unsigned pv_mda_set_ignored(const struct physical_volume *pv, unsigned mda_ignored)
{
struct lvmcache_info *info;
struct _pv_mda_set_ignored_baton baton;
struct metadata_area *mda;
if (!(info = lvmcache_info_from_pvid((const char *)&pv->id.uuid, pv->dev, 0)))
return_0;
baton.mda_ignored = mda_ignored;
baton.mdas_in_use = &pv->fid->metadata_areas_in_use;
baton.mdas_ignored = &pv->fid->metadata_areas_ignored;
baton.mdas_to_change = baton.mda_ignored ? baton.mdas_in_use : baton.mdas_ignored;
if (is_orphan(pv)) {
dm_list_iterate_items(mda, baton.mdas_to_change)
mda_set_ignored(mda, baton.mda_ignored);
return 1;
}
/*
* Do not allow disabling of the the last PV in a VG.
*/
if (pv_mda_used_count(pv) == vg_mda_used_count(pv->vg)) {
log_error("Cannot disable all metadata areas in volume group %s.",
pv->vg->name);
return 0;
}
/*
* Non-orphan case is more complex.
* If the PV's mdas are ignored, and we wish to un-ignore,
* we clear the bit and move them from the ignored mda list to the
* in_use list, ensuring the new state will get written to disk
* in the vg_write() path.
* If the PV's mdas are not ignored, and we are setting
* them to ignored, we set the bit but leave them on the in_use
* list, ensuring the new state will get written to disk in the
* vg_write() path.
*/
/* FIXME: Try not to update the cache here! Also, try to iterate over
* PV mdas only using the format instance's index somehow
* (i.e. try to avoid using mda_locn_match call). */
lvmcache_foreach_mda(info, _pv_mda_set_ignored_one, &baton);
return 1;
}
struct label *pv_label(const struct physical_volume *pv)
{
struct lvmcache_info *info =
lvmcache_info_from_pvid((const char *)&pv->id.uuid, pv->dev, 0);
if (info)
return lvmcache_get_label(info);
/* process_each_pv() may create dummy PVs that have no label */
if (pv->vg && pv->dev)
log_error(INTERNAL_ERROR "PV %s unexpectedly not in cache.",
dev_name(pv->dev));
return NULL;
}