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45 Commits

Author SHA1 Message Date
David Teigland
d59382c772 devices file: do not clear PVID of unread devices
In a certain disconnected state, a block device is present on
the system, can be opened, reports a valid size, reports the
correct device id (wwid), and matches a devices file entry.
But, reading the device can still fail.  In this case,
device_ids_validate() was misinterpreting the read error as
the device having no data/label on it (and no PVID).
The validate function would then clear the PVID from the
devices file entry for the device, thinking that it was
fixing the devices file (making it consistent with the on disk
state.)  Fix this by not attempting to check and correct a
devices file entry that cannot be read.  Also make this case
explicit in the hints validation code (which was doing the
right thing but indirectly.)
2022-02-10 14:16:04 -06:00
David Teigland
5c4ce4669e device_id: searched_devnames improvements
Remove the searched_devnames file in a couple more places:
. When hints need refreshing it's possible that a missing
  devices file entry could be found by searching devices
  again.
. When a devices file entry devname is first found to be
  incorrect, a new search for missing entries may be
  useful.
2021-11-16 14:29:17 -06:00
David Teigland
62533ae3fa vgchange -aay: optimize device list using pvs_online files
Port another optimization from pvscan -aay to vgchange -aay:
  "pvscan: only add device args to dev cache"

This optimization avoids doing a full dev_cache_scan, and
instead populates dev-cache with only the devices in the
VG being activated.

This involves shifting the use of pvs_online files from
the hints interface up to the higher level label_scan
interface.  This specialized label_scan is structured
around creating a list of devices from the pvs_online
files.  Previously, a list of all devices was created
first, and then reduced based on the pvs_online files.
The initial step of listing all devices was slow when
thousands of devices are present on the system.

This optimization extends the previous optimization that
used pvs_online files to limit the devices that were
actually scanned (i.e. reading to identify the device):
  "vgchange -aay: optimize device scan using pvs_online files"
2021-11-05 12:19:35 -05:00
David Teigland
f40fd88374 move code from pvscan.c to online.c
related to managing files in /run/lvm/pvs_online
and /run/lvm/vgs_online
2021-11-04 11:09:29 -05:00
David Teigland
726dd25969 add hints interface to the pvs_online file information
The information in /run/lvm/pvs_online/<pvid> files can
be used to build a list of devices for a given VG.

The pvscan -aay command has long used this information to
activate a VG while scanning only devices in that VG, which
is an important optimization for autoactivation.

This patch implements the same thing through the existing
device hints interface, so that the optimization can be
applied elsewhere.  A future patch will take advantage of
this optimization in vgchange -aay, which is now used in
place of pvscan -aay for event activation.
2021-11-04 10:58:16 -05:00
David Teigland
5d0964d127 hints: remove the cmd hints list
which is no longer used after commit
"toollib: remove all devices list from process_each_pv"
2021-11-01 16:01:45 -05:00
Zdenek Kabelac
8c44597820 gcc-fanalyzer: zallocate memory for clean buffer 2021-09-21 21:03:47 +02:00
Zdenek Kabelac
bc1bc4cffc debug: drop stack from regular code flow 2021-03-15 11:13:24 +01:00
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
David Teigland
46f43589d0 hints: enhance debug messages 2020-09-16 15:01:10 -05:00
Zdenek Kabelac
6d344b4ac0 hints: enhance debug with log_sys_debug 2020-09-15 22:52:25 +02:00
David Teigland
8b9028bbe7 hints: remove warning when clearing hint file
When the hint file cannot be accessed, silently
ignore hints, like other instances do.
2020-09-02 14:06:46 -05:00
Zdenek Kabelac
a481f42630 cov: always initialized values
Make sure values are initialized for all possible paths.
2020-09-01 17:57:50 +02:00
Zdenek Kabelac
85e2c7e14d cov: explicitely ignore function result 2020-09-01 17:57:50 +02:00
Zdenek Kabelac
1705b439b1 cov: always sure we end with '0'
Use easier dm_strncpy().
2020-09-01 17:57:50 +02:00
Zdenek Kabelac
19e9c88faf gcc: do not use return with void function
Follow C norm and do not use 'return' in void function to call other
functions.
2020-08-28 21:43:03 +02:00
Zdenek Kabelac
ee0cb17608 gcc: use apropriate type for reading and printing values 2020-08-28 21:43:03 +02:00
Zdenek Kabelac
cca2a652d1 cov: avoid double call of free_hints() on error path
Since we 'free_hints()' on return error path from call of
_read_hint_file(), avoid calling it twice in the middle of
error path process.
2020-06-24 15:01:03 +02:00
David Teigland
5c095400de hints: free hint structs on exit
and free on a couple error paths.
2020-05-13 17:20:16 -05:00
David Teigland
2f29765e7f devs: add some checks for a dev with no path name
It's possible for a dev-cache entry to remain after all
paths for it have been removed, and other parts of the
code expect that a dev always has a name.  A better fix
may be to remove a device from dev-cache after all paths
to it have been removed.
2020-05-13 16:26:26 -05:00
David Teigland
f50e7ce76c hints: free hint list in error exit path 2020-03-03 12:25:34 -06:00
Zdenek Kabelac
de43527f94 cov: unused header file removal
cov: unused header removed
Also ensure library header file with config settings goes first.
Move inclusion of format-text.h into layout.h
2020-02-04 17:22:06 +01:00
David Teigland
7ea71a9eb9 Revert "hints: rewrite function"
This reverts commit 70fb31b5d6.
2019-11-14 12:15:05 -06:00
David Teigland
31a862a6be Revert "debug: enhance debug messages"
This reverts commit e92d3bd1f7.
2019-11-14 12:11:53 -06:00
Zdenek Kabelac
e92d3bd1f7 debug: enhance debug messages 2019-11-14 18:06:42 +01:00
Zdenek Kabelac
14e01d6316 hints: drop unneeded memset
strncpy will zero buffer itself.
2019-11-14 18:06:42 +01:00
Zdenek Kabelac
1760b96368 hints: no need to check for NULL before free
free() itself checks for NULL.
2019-11-14 18:06:42 +01:00
Zdenek Kabelac
61a483a654 hints: check for _touch_hints
Exit when !_touch_hints().
2019-11-14 18:06:42 +01:00
Zdenek Kabelac
c38be06531 hints: fix mem leaking buffers 2019-11-14 18:06:42 +01:00
Zdenek Kabelac
1349a52626 hints: validate allocation result 2019-11-14 18:06:42 +01:00
Zdenek Kabelac
219fe72359 hints: validate sscanf results 2019-11-14 18:06:42 +01:00
Zdenek Kabelac
d4d82dbb70 hints: allocate hint only when needed
Avoid mem leaking hint on every loop continue and
allocate hint only when it's going to be added into list.

Switch to use 'dm_strncpy()' and validate sizes.
2019-11-14 18:06:42 +01:00
Zdenek Kabelac
70fb31b5d6 hints: rewrite function 2019-11-14 18:06:42 +01:00
David Teigland
5b3fbccab9 hints: check for malloc failure 2019-08-28 12:41:57 -05:00
David Teigland
12707adac8 hints: fix copy of filter
Only the first entry of the filter array was being
included in the copy of the filter, rather than the
entire thing.  The result is that hints would not be
refreshed if the filter was changed but the first
entry was unchanged.
2019-08-28 12:33:04 -05:00
David Teigland
677833ce6f lvmcache: renaming functions and variables
related to duplicates, no functional changes.
2019-08-16 13:26:11 -05:00
David Teigland
60bf9c9f33 hints: exclude md components
In some cases md components could be included in
the hints, so add a check to hint creation to make
sure they are excluded.
2019-05-21 11:58:01 -05:00
David Teigland
c3e385c108 hints: skip hint flock if nolocking option is set 2019-04-29 13:01:15 -05:00
David Teigland
8c87dda195 locking: unify global lock for flock and lockd
There have been two file locks used to protect lvm
"global state": "ORPHANS" and "GLOBAL".

Commands that used the ORPHAN flock in exclusive mode:
  pvcreate, pvremove, vgcreate, vgextend, vgremove,
  vgcfgrestore

Commands that used the ORPHAN flock in shared mode:
  vgimportclone, pvs, pvscan, pvresize, pvmove,
  pvdisplay, pvchange, fullreport

Commands that used the GLOBAL flock in exclusive mode:
  pvchange, pvscan, vgimportclone, vgscan

Commands that used the GLOBAL flock in shared mode:
  pvscan --cache, pvs

The ORPHAN lock covers the important cases of serializing
the use of orphan PVs.  It also partially covers the
reporting of orphan PVs (although not correctly as
explained below.)

The GLOBAL lock doesn't seem to have a clear purpose
(it may have eroded over time.)

Neither lock correctly protects the VG namespace, or
orphan PV properties.

To simplify and correct these issues, the two separate
flocks are combined into the one GLOBAL flock, and this flock
is used from the locking sites that are in place for the
lvmlockd global lock.

The logic behind the lvmlockd (distributed) global lock is
that any command that changes "global state" needs to take
the global lock in ex mode.  Global state in lvm is: the list
of VG names, the set of orphan PVs, and any properties of
orphan PVs.  Reading this global state can use the global lock
in sh mode to ensure it doesn't change while being reported.

The locking of global state now looks like:

lockd_global()
  previously named lockd_gl(), acquires the distributed
  global lock through lvmlockd.  This is unchanged.
  It serializes distributed lvm commands that are changing
  global state.  This is a no-op when lvmlockd is not in use.

lockf_global()
  acquires an flock on a local file.  It serializes local lvm
  commands that are changing global state.

lock_global()
  first calls lockf_global() to acquire the local flock for
  global state, and if this succeeds, it calls lockd_global()
  to acquire the distributed lock for global state.

Replace instances of lockd_gl() with lock_global(), so that the
existing sites for lvmlockd global state locking are now also
used for local file locking of global state.  Remove the previous
file locking calls lock_vol(GLOBAL) and lock_vol(ORPHAN).

The following commands which change global state are now
serialized with the exclusive global flock:

pvchange (of orphan), pvresize (of orphan), pvcreate, pvremove,
vgcreate, vgextend, vgremove, vgreduce, vgrename,
vgcfgrestore, vgimportclone, vgmerge, vgsplit

Commands that use a shared flock to read global state (and will
be serialized against the prior list) are those that use
process_each functions that are based on processing a list of
all VG names, or all PVs.  The list of all VGs or all PVs is
global state and the shared lock prevents those lists from
changing while the command is processing them.

The ORPHAN lock previously attempted to produce an accurate
listing of orphan PVs, but it was only acquired at the end of
the command during the fake vg_read of the fake orphan vg.
This is not when orphan PVs were determined; they were
determined by elimination beforehand by processing all real
VGs, and subtracting the PVs in the real VGs from the list
of all PVs that had been identified during the initial scan.
This is fixed by holding the single global lock in shared mode
while processing all VGs to determine the list of orphan PVs.
2019-04-29 13:01:05 -05:00
David Teigland
d0b869e46a hints: fix non-empty hints list when not using hints
When hints are invalid and ignored, the list of hints
could be non-empty (from additions before an invalid
hint was found).  This confused the calling code which
was checking for an empty list to see if hints were used.
Ensure the list is empty when hints are not used.
2019-04-11 11:58:51 -05:00
David Teigland
0cc80ccfd5 hints: fix case of error getting device size
When checking hints, if there's an error getting
the device size, that should be equivalent to
seeing zero size.
2019-04-11 10:32:28 -05:00
David Teigland
0aa51a2f61 hints: fix recreating hints from pvscan
When aay was included in the pvscan --cache command,
the activation part was complaining about the unusual
state of the hint file since it had been recreated
just prior.
2019-02-13 15:23:43 -06:00
David Teigland
5f102b3421 hints: invalidate when pvscan --cache sees a new PV
An idea from Zdenek for better ensuring valid hints by invalidating
them when pvscan --cache <device> sees a new PV, which is a case
where we know that hints should be invalidated.  This is triggered
from systemd/udev logic, and there may be some cases where it would
invalidate hints that the existing methods wouldn't detect.
2019-01-16 15:34:20 -06:00
David Teigland
7b5abc3fb1 hints: fix hint flock when using lvm shell
also cmd->use_hints needs to be set for each shell command
2019-01-15 12:23:16 -06:00
David Teigland
6620dc9475 add device hints to reduce scanning
Save the list of PVs in /run/lvm/hints.  These hints
are used to reduce scanning in a number of commands
to only the PVs on the system, or only the PVs in a
requested VG (rather than all devices on the system.)
2019-01-15 10:23:47 -06:00