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Commit Graph

19 Commits

Author SHA1 Message Date
Zdenek Kabelac
d2522f4a05 polldaemon: improve support for interruptions
Enhance handling of interruptions of polling process and lvmpoll daemon.
Daemon should now react much faster on interrups (i.e. shutdown
sequence) and avoid taking lenghty sleep waiting on pvmove signaling.
2021-04-06 22:02:31 +02:00
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
Zdenek Kabelac
44cfa55843 libdaemon: use pselect to avoid condition checking race
To avoid tiny race on checking arrival of signal and entering select
(that can latter remain stuck as signal was already delivered) switch
to use  pselect().

If it would needed, we can eventually add extra code for older systems
without pselect(), but there are probably no such ancient systems in
use.
2019-04-16 12:18:34 +02:00
Joe Thornber
d5da55ed85 device_mapper: remove dbg_malloc.
I wrote dbg_malloc before we had valgrind.  These days there's just
no need.
2018-06-08 13:40:53 +01:00
Zdenek Kabelac
fcbef05aae doc: change fsf address
Hmm rpmlint suggest fsf is using a different address these days,
so lets keep it up-to-date
2016-01-21 12:11:37 +01:00
Zdenek Kabelac
32762e2a9c libdaemon: fix passing 32bit values for %d
Since %d is now prohibited for its great confusion,
replace it with  FMTd64 and correctly converted int64_t
parameter.
2015-11-09 17:04:10 +01:00
Ondrej Kozina
7bbc128c3d lvmpolld: make lvpoll error messages visible
Previously all stderr messages issued by spawned lvpoll command were reported
as INFO only. This made all such messages invisible in syslog or lvmpolld log
while running default configuration.

All lvpoll stderr messages are loged with WARN priority now and lvpoll
command exiting with retcode != 0 is logged with ERROR priority in
syslog and lvmpolld log
2015-09-02 17:24:26 +02:00
Zdenek Kabelac
3a3e17d603 cleanup: check pthread result codes 2015-08-18 15:00:08 +02:00
Peter Rajnoha
46e6b2b86e coverity: fix possible resource leak in lvmpolld-core
/daemons/lvmpolld/lvmpolld-core.c:573: leaked_storage: Variable "cmdargv" going out of scope leaks the storage it points to.
2015-08-04 09:25:47 +02:00
Marian Csontos
738ae4a77f lvmpolld: Fix segfault on 32 bit architectures
Explicit conversions are needed to align writes and reads on the stack.
int64_t is popped from stack while int was pushed.
2015-07-10 16:16:57 +02:00
Zdenek Kabelac
ac6b355978 cleanup: drop double const
Second const is unneeded.
Also always create whole array with MAX elements.
2015-06-15 14:46:44 +02:00
Ondrej Kozina
1aba262edb lvmpolld: terminate error message with a dot and LF 2015-05-27 11:10:43 +02:00
Ondrej Kozina
c069aff21b lvmpolld: zero errno in before strtoul call
Testing errno value without explicitly setting to
zero in before the strtoul call may lead to
unexpected failures.
2015-05-26 16:27:03 +02:00
Ondrej Kozina
d4317c0406 lvmpolld: don't return success on invalid option 2015-05-15 20:33:40 +02:00
Ondrej Kozina
d34de2d912 lvmpolld: add long option variants for all short ones 2015-05-15 20:33:34 +02:00
Ondrej Kozina
b91e1ea95e lvmpolld: introduce client functionality
as of now lvmpolld works as client utility for
querying running instance of lvmpolld server
on metadata, state, etc.

Currently the only request implemented is the '--dump'.
It prints out full lvmpolld state (mimics lvmdump -p command).
2015-05-15 20:33:27 +02:00
Ondrej Kozina
333fdfd4b6 lvmpolld: label known return codes
so that lvmpolld-client can decode and describe these
return codes properly
2015-05-15 20:31:48 +02:00
Ondrej Kozina
d5cef7413f lvmpolld: dump cleanup 2015-05-12 17:17:07 +02:00
Ondrej Kozina
e587b0677b lvmpolld: Add standalone polldaemon.
See doc/lvmpolld_overview.txt
2015-05-09 00:59:18 +01:00