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Commit Graph

17 Commits

Author SHA1 Message Date
Zdenek Kabelac
6430a6ca63 const: _fns poll_function 2024-05-04 01:01:57 +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
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
6a1f458bb7 build: compile fixes 2018-06-01 21:12:31 +02:00
Joe Thornber
7f97c7ea9a build: Don't generate symlinks in include/ dir
As we start refactoring the code to break dependencies (see doc/refactoring.txt),
I want us to use full paths in the includes (eg, #include "base/data-struct/list.h").
This makes it more obvious when we're breaking abstraction boundaries, eg, including a file in
metadata/ from base/
2018-05-14 10:30:20 +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
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
Peter Rajnoha
e8dbaf62d3 coverity: previous commit - not "break" but "fall through" 2015-07-08 14:42:31 +02:00
Peter Rajnoha
705fee709f coverity: missing break in switch expression
lib/lvmpolld/lvmpolld-client.c:109: fallthrough: The above case falls through to this one
2015-07-08 14:36:02 +02:00
Ondrej Kozina
6d998aa13d lvmpolld-client.c: debug print when querying progress 2015-05-21 11:20:21 +02:00
David Teigland
7a8ce8dbf7 polldaemon: remove get_copy_vg and get_copy_lv wrappers
These wrappers have been replaced by direct calls
to vg_read() and find_lv() in previous commits.

This commit should have no functional impact since
all bits were already unreachable.
2015-05-19 20:56:15 +02:00
Ondrej Kozina
6cdd153b89 lvmpolld-client.c: explain known return codes
lvmpolld returns few well known return codes. Explain
these to users and suggest reading lvmpolld log files
for more details
2015-05-15 20:31:54 +02:00
Ondrej Kozina
8da7915222 lvmpolld-client.c: use lvmpolld debug class where appropriate 2015-05-12 17:17:00 +02:00
Ondrej Kozina
24a92e08c0 lvmpolld-client.c: be more specific about fallback on error
if client fails to contact lvmpolld it fallbacks to using classical
polldaemon. Be more specific and give some hints to users what went
possibly wrong
2015-05-12 17:16:43 +02:00
Ondrej Kozina
5e0a8fa981 lib/polldaemon.h: remove trailing whitespace 2015-05-11 19:07:55 +02:00
Ondrej Kozina
e587b0677b lvmpolld: Add standalone polldaemon.
See doc/lvmpolld_overview.txt
2015-05-09 00:59:18 +01:00