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16270 Commits

Author SHA1 Message Date
David Teigland
a3a676e0e7 metadata.c: removed unused code
if 0 was placed around old vg_read code by
the previous commit.
2019-06-07 15:54:04 -05:00
David Teigland
ba7ff96faf improve reading and repairing vg metadata
The fact that vg repair is implemented as a part of vg read
has led to a messy and complicated implementation of vg_read,
and limited and uncontrolled repair capability.  This splits
read and repair apart.

Summary
-------

- take all kinds of various repairs out of vg_read
- vg_read no longer writes anything
- vg_read now simply reads and returns vg metadata
- vg_read ignores bad or old copies of metadata
- vg_read proceeds with a single good copy of metadata
- improve error checks and handling when reading
- keep track of bad (corrupt) copies of metadata in lvmcache
- keep track of old (seqno) copies of metadata in lvmcache
- keep track of outdated PVs in lvmcache
- vg_write will do basic repairs
- new command vgck --updatemetdata will do all repairs

Details
-------

- In scan, do not delete dev from lvmcache if reading/processing fails;
  the dev is still present, and removing it makes it look like the dev
  is not there.  Records are now kept about the problems with each PV
  so they be fixed/repaired in the appropriate places.

- In scan, record a bad mda on failure, and delete the mda from
  mda in use list so it will not be used by vg_read or vg_write,
  only by repair.

- In scan, succeed if any good mda on a device is found, instead of
  failing if any is bad.  The bad/old copies of metadata should not
  interfere with normal usage while good copies can be used.

- In scan, add a record of old mdas in lvmcache for later, do not repair
  them while reading, and do not let them prevent us from finding and
  using a good copy of metadata from elsewhere.  One result is that
  "inconsistent metadata" is no longer a read error, but instead a
  record in lvmcache that can be addressed separate from the read.

- Treat a dev with no good mdas like a dev with no mdas, which is an
  existing case we already handle.

- Don't use a fake vg "handle" for returning an error from vg_read,
  or the vg_read_error function for getting that error number;
  just return null if the vg cannot be read or used, and an error_flags
  arg with flags set for the specific kind of error (which can be used
  later for determining the kind of repair.)

- Saving an original copy of the vg metadata, for purposes of reverting
  a write, is now done explicitly in vg_read instead of being hidden in
  the vg_make_handle function.

- When a vg is not accessible due to "access restrictions" but is
  otherwise fine, return the vg through the new error_vg arg so that
  process_each_pv can skip the PVs in the VG while processing.
  (This is a temporary accomodation for the way process_each_pv
  tracks which devs have been looked at, and can be dropped later
  when process_each_pv implementation dev tracking is changed.)

- vg_read does not try to fix or recover a vg, but now just reads the
  metadata, checks access restrictions and returns it.
  (Checking access restrictions might be better done outside of vg_read,
   but this is a later improvement.)

- _vg_read now simply makes one attempt to read metadata from
  each mda, and uses the most recent copy to return to the caller
  in the form of a 'vg' struct.
  (bad mdas were excluded during the scan and are not retried)
  (old mdas were not excluded during scan and are retried here)

- vg_read uses _vg_read to get the latest copy of metadata from mdas,
  and then makes various checks against it to produce warnings,
  and to check if VG access is allowed (access restrictions include:
  writable, foreign, shared, clustered, missing pvs).

- Things that were previously silently/automatically written by vg_read
  that are now done by vg_write, based on the records made in lvmcache
  during the scan and read:
  . clearing the missing flag
  . updating old copies of metadata
  . clearing outdated pvs
  . updating pv header flags

- Bad/corrupt metadata are now repaired; they were not before.

Test changes
------------

- A read command no longer writes the VG to repair it, so add a write
  command to do a repair.
  (inconsistent-metadata, unlost-pv)

- When a missing PV is removed from a VG, and then the device is
  enabled again, vgck --updatemetadata is needed to clear the
  outdated PV before it can be used again, where it wasn't before.
  (lvconvert-repair-policy, lvconvert-repair-raid, lvconvert-repair,
   mirror-vgreduce-removemissing, pv-ext-flags, unlost-pv)

Reading bad/old metadata
------------------------

- "bad metadata": the mda_header or metadata text has invalid fields
  or can't be parsed by lvm.  This is a form of corruption that would
  not be caused by known failure scenarios.  A checksum error is
  typically included among the errors reported.

- "old metadata": a valid copy of the metadata that has a smaller seqno
  than other copies of the metadata.  This can happen if the device
  failed, or io failed, or lvm failed while commiting new metadata
  to all the metadata areas.  Old metadata on a PV that has been
  removed from the VG is the "outdated" case below.

When a VG has some PVs with bad/old metadata, lvm can simply ignore
the bad/old copies, and use a good copy.  This is why there are
multiple copies of the metadata -- so it's available even when some
of the copies cannot be used.  The bad/old copies do not have to be
repaired before the VG can be used (the repair can happen later.)

A PV with no good copies of the metadata simply falls back to being
treated like a PV with no mdas; a common and harmless configuration.

When bad/old metadata exists, lvm warns the user about it, and
suggests repairing it using a new metadata repair command.
Bad metadata in particular is something that users will want to
investigate and repair themselves, since it should not happen and
may indicate some other problem that needs to be fixed.

PVs with bad/old metadata are not the same as missing devices.
Missing devices will block various kinds of VG modification or
activation, but bad/old metadata will not.

Previously, lvm would attempt to repair bad/old metadata whenever
it was read.  This was unnecessary since lvm does not require every
copy of the metadata to be used.  It would also hide potential
problems that should be investigated by the user.  It was also
dangerous in cases where the VG was on shared storage.  The user
is now allowed to investigate potential problems and decide how
and when to repair them.

Repairing bad/old metadata
--------------------------

When label scan sees bad metadata in an mda, that mda is removed
from the lvmcache info->mdas list.  This means that vg_read will
skip it, and not attempt to read/process it again.  If it was
the only in-use mda on a PV, that PV is treated like a PV with
no mdas.  It also means that vg_write will also skip the bad mda,
and not attempt to write new metadata to it.  The only way to
repair bad metadata is with the metadata repair command.

When label scan sees old metadata in an mda, that mda is kept
in the lvmcache info->mdas list.  This means that vg_read will
read/process it again, and likely see the same mismatch with
the other copies of the metadata.  Like the label_scan, the
vg_read will simply ignore the old copy of the metadata and
use the latest copy.  If the command is modifying the vg
(e.g. lvcreate), then vg_write, which writes new metadata to
every mda on info->mdas, will write the new metadata to the
mda that had the old version.  If successful, this will resolve
the old metadata problem (without needing to run a metadata
repair command.)

Outdated PVs
------------

An outdated PV is a PV that has an old copy of VG metadata
that shows it is a member of the VG, but the latest copy of
the VG metadata does not include this PV.  This happens if
the PV is disconnected, vgreduce --removemissing is run to
remove the PV from the VG, then the PV is reconnected.
In this case, the outdated PV needs have its outdated metadata
removed and the PV used flag needs to be cleared.  This repair
will be done by the subsequent repair command.  It is also done
if vgremove is run on the VG.

MISSING PVs
-----------

When a device is missing, most commands will refuse to modify
the VG.  This is the simple case.  More complicated is when
a command is allowed to modify the VG while it is missing a
device.

When a VG is written while a device is missing for one of it's PVs,
the VG metadata is written to disk with the MISSING flag on the PV
with the missing device.  When the VG is next used, it is treated
as if the PV with the MISSING flag still has a missing device, even
if that device has reappeared.

If all LVs that were using a PV with the MISSING flag are removed
or repaired so that the MISSING PV is no longer used, then the
next time the VG metadata is written, the MISSING flag will be
dropped.

Alternative methods of clearing the MISSING flag are:

vgreduce --removemissing will remove PVs with missing devices,
or PVs with the MISSING flag where the device has reappeared.

vgextend --restoremissing will clear the MISSING flag on PVs
where the device has reappeared, allowing the VG to be used
normally.  This must be done with caution since the reappeared
device may have old data that is inconsistent with data on other PVs.

Bad mda repair
--------------

The new command:
vgck --updatemetadata VG

first uses vg_write to repair old metadata, and other basic
issues mentioned above (old metadata, outdated PVs, pv_header
flags, MISSING_PV flags).  It will also go further and repair
bad metadata:

. text metadata that has a bad checksum
. text metadata that is not parsable
. corrupt mda_header checksum and version fields

(To keep a clean diff, #if 0 is added around functions that
are replaced by new code.  These commented functions are
removed by the following commit.)
2019-06-07 15:54:04 -05:00
David Teigland
015b906069 add a warning message when updating old metadata
in an mda that had previously not been updated
2019-06-07 15:54:04 -05:00
David Teigland
5dd32680b0 vgcfgbackup add error messages 2019-06-07 15:54:04 -05:00
David Teigland
47effdc025 vgck --updatemetadata is a new command
uses vg_write to correct more common or less severe issues,
and also adds the ability to repair some metadata corruption
that couldn't be handled previously.
2019-06-07 15:54:04 -05:00
David Teigland
de3d3b11f4 move pv header repairs to vg_write
Correct PV header in-use or version fields
from vg_write instead of vg_read.
2019-06-07 15:54:04 -05:00
David Teigland
89914a541f process_each_pv handle outdated pvs
process_each_pv should account for outdated pvs
in the list of all devices it is processing.
2019-06-07 15:54:04 -05:00
David Teigland
ab61a6d85d move wipe_outdated_pvs to vg_write
and implement it based on a device, not based
on a pv struct (which is not available when the
device is not a part of the vg.)

currently only the vgremove command wipes outdated
pvs until more advanced recovery is added in a
subsequent commit
2019-06-07 15:54:04 -05:00
David Teigland
45b164f62c create separate lvmcache update functions for read and write
The vg read and vg write cases need to update lvmcache
differently, so create separate functions for them.

The read case now handles checking for outdated mdas
and moves them aside into a new list to be repaired in
a subsequent commit.
2019-06-07 15:54:04 -05:00
David Teigland
027e0e92e6 fix vg_commit return value
The existing comment was desribing the correct behavior,
but the code didn't match.  The commit is successful if
one mda was committed.  Making it depend on the result of
the internal lvmcache update was wrong.
2019-06-07 15:54:04 -05:00
David Teigland
86d831b916 change args for text label read function
Have the caller pass the label_sector to the read
function so the read function can set the sector
field in the label struct, instead of having the
read function return a pointer to the label for
the caller to set the sector field.

Also have the read function return a flag indicating
to the caller that the scanned device was identified
as a duplicate pv.
2019-06-07 15:54:04 -05:00
David Teigland
889b5d3183 add mda arg to add_mda
Allow the caller of lvmcache_add_mda() to have the
new mda returned.
2019-06-07 15:54:04 -05:00
David Teigland
b2447e3538 keep track of which mdas have old metadata in lvmcache
This will be used for more advanced repair in a
subsequent commit.
2019-06-07 15:54:04 -05:00
David Teigland
0b18c25d93 ability to keep track of outdated pvs in lvmcache
Outdated PVs hold metadata for VG from which they
have been removed.  Add the ability to keep track
of these in lvmcache.
This will be used for more advanced repair in a
subsequent commit.
2019-06-07 15:54:04 -05:00
David Teigland
650524b955 ability to keep track of bad mdas in lvmcache
mda's that cannot be processed by lvm because of
some corruption can be kept on a separate list.
These will be used for more advanced repair in a
subsequent commit.
2019-06-07 15:54:04 -05:00
David Teigland
aeafdc1f45 add flags to keep track of bad metadata
When reading metadata headers and text, use a new set
of flags to identify specific errors that are seen.
These will be used for more advanced repair in a
subsequent commit.
2019-06-07 15:54:04 -05:00
David Teigland
db98a6e362 Additional MD component checking
If udev info is missing for a device, (which would indicate
if it's an MD component), then do an end-of-device read to
check if a PV is an MD component.  (This is skipped when
using hints since we already know devs in hints are good.)

A new config setting md_component_checks can be used to
disable the additional end-of-device MD checks, or to
always enable end-of-device MD checks.

When both hints and udev info are disabled/unavailable,
the end of PVs will now be scanned by default.  If md
devices with end-of-device superblocks are not being
used, the extra I/O overhead can be avoided by setting
md_component_checks="start".
2019-06-07 13:27:16 -05:00
Marian Csontos
24bd35b4ce Merge remote-tracking branch 'origin/master'
* origin/master:
  lvmcache: remove unused_duplicate_devs list from cmd
2019-06-07 17:29:45 +02:00
Marian Csontos
4d11bf8d50 post-release 2019-06-07 17:24:51 +02:00
Marian Csontos
cb6277aa8a pre-release 2019-06-07 17:24:51 +02:00
David Teigland
2bcd43c683 lvmcache: remove unused_duplicate_devs list from cmd
Save the previous duplicate PVs in a global list instead
of a list on the cmd struct.  dmeventd reuses the cmd struct
for multiple commands, and the list entries between commands
were being freed (apparently), causing a segfault in dmeventd
when it tried to use items in cmd->unused_duplicate_devs
that had been saved there by the previous command.
2019-06-07 10:14:33 -05:00
David Teigland
c315112a3b tests: pvscan-autoactivate check for machine-id 2019-06-06 15:32:42 -05:00
David Teigland
2b241eb1f6 pvck: use new dump routines for old output
Use the recently added dump routines to produce the
old/traditional pvck output, and remove the code that
had been used for that.

The validation/checking done by the new routines means
that new lines prefixed with CHECK are printed for
incorrect values.
2019-06-05 16:28:52 -05:00
David Teigland
356ea897cc tests: pvck-dump 2019-06-05 13:58:26 -05:00
David Teigland
bada89a224 pvck: dump metadata_all
This searches the entire metadata area for any
copy of the metadata and dumps it to file.
2019-06-05 12:25:34 -05:00
Zdenek Kabelac
4d9f41b119 tests: check no_discard_passdown
Check reporting works
2019-06-05 15:48:44 +02:00
Zdenek Kabelac
ddd68fbead tests: automatically set scan_lvs when using extend_filter
When using 'aux extend_filter' we always want to use LV as PV.
2019-06-05 15:48:44 +02:00
Zdenek Kabelac
e3c4ab0cc7 cache: support no_discard_passdown
Recent kernel version from kernel commit:
de7180ff908b2bc0342e832dbdaa9a5f1ecaa33a
started to report in cache status line new flag:
no_discard_passdown

Whenever lvm spots unknown status it reports:
Unknown feature in status:

So add reconginzing this feature flag and also report this with

'lvs -o+kernel_discards'

When no_discard_passdown is found in status 'nopassdown' gets reported
for this field  (roughly matching what we report for thin-pools).
2019-06-05 15:48:41 +02:00
David Teigland
d18e491f68 pvck: dump headers and metadata
Add 'pvck --dump headers' to print all the
lvm ondisk structs.  Also checks the values
and prints any problems.

The previous dump metadata is also converted to
use these same routines, which do not depend on lvm
fully scanning/reading/processing the headers and
metadata on disk.  This makes it useful to get data in
cases where there is corruption that would otherwise
prevent the normal functions from working.
2019-06-03 15:13:32 -05:00
Marian Csontos
669a834981 test: Increase latency in pvmove-resume-multiseg
The test was failing consistently on some VMs (F25), and inconsistently
on Rawhide.

With increased latency these failures are no longer reproducible.

Reproducer:

    make check_lvmpolld T=pvmove-resume-multiseg.sh
2019-06-03 16:57:49 +02:00
Marian Csontos
a9907bef99 test: Restore testing of D-Bus API 2019-05-31 08:58:30 +02:00
David Teigland
eebb5e9fff tests: add debug to pvscan-cache deactivation 2019-05-23 15:32:46 -05:00
David Teigland
e055b89d28 tests: pvscan-cache more attempts to fix 2019-05-23 14:55:57 -05:00
David Teigland
645dd27604 separate code for setting devices from metadata parsing
Pull the code that sets devs for PVs out of the metadata
parsing code and call it separately.
2019-05-23 11:57:38 -05:00
David Teigland
ef2d61fea8 WHATS_NEW: pvck --dump 2019-05-23 11:50:16 -05:00
David Teigland
52586b1039 pvck: new dump option to extract metadata
The new command 'pvck --dump metadata PV' will extract
the current version of VG metadata from a PV for testing
and debugging.  --dump metadata_area extracts the entire
text metadata area.
2019-05-23 11:49:06 -05:00
David Teigland
1022b88a66 tests: change mkfs usage in lvconvert raid tests
The "echo y | mkfs" was failing at times from echo y.
Remove echo y and replace with wipefs -a prior to mkfs.
2019-05-23 11:45:26 -05:00
David Teigland
6169c0a51b tests: fix error detection in lvconvert-raid-takeover.sh 2019-05-23 10:29:52 -05:00
David Teigland
2036608423 tests: pvscan-cache try to fix teardown problems
teardown after the test was failing, probably because
of uncoordinated udev actions running on the test
system.  Try to avoid this by doing some work before
teardown.
2019-05-22 11:55:48 -05:00
David Teigland
78afe75b08 tests: fsadm-crypt.sh update mkfs parameter
mkfs.xfs was rejecting previously working value
2019-05-21 14:46:01 -05:00
David Teigland
cf3f463929 tests: pvscan-autoactivate.sh switch system_id_source
to machineid instead of uname which would break if
the test system had no proper uname set.
2019-05-21 14:37:55 -05:00
David Teigland
99ca06ca46 tests: hints check if strace exists
avoid test failure if test system does not
have strace
2019-05-21 14:24:57 -05:00
David Teigland
dc1e12dcd4 scan: expand and update label scan comments 2019-05-21 12:02:40 -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
6422b9ddc5 move the setting of use_full_md_check flag
from each command to one location in command init.
No functional change.
2019-05-21 11:51:58 -05:00
David Teigland
19ef399ea7 devs: rename dev_is_md dev_is_md_component
The naming was confusing and misleading since
it it's testing if a device is an md component,
not an md device.
2019-05-21 11:44:39 -05:00
Zdenek Kabelac
0c26aa13ca tests: check accepting out-of-range creation_time 2019-05-10 15:00:21 +02:00
Zdenek Kabelac
85dbcda150 metadata: allow reading metadata with invalid creation_time
lvm2 till version 2.02.169 (commit 78d004efa8)
was printing invalid creation_time argument into metadata on 32bit arch.

However with commit ba9820b142 we started
to properly validate all input numbers and thus we refused to accept
invalid metadata with 'garbage' string - but this results in the
situation where metadata produced on older lvm2 on 32 bit architecture
will become unreadable after upgrade.

To fix this case - extend libdm parser in a way, that whenever we
find error integer value, we also check if the parsed value is not for
creation_time node and in this case we let the metadata pass through
with made-up date 2018-05-24 (release date of 2.02.169).
2019-05-10 14:40:11 +02:00
Zdenek Kabelac
1f7c9da554 tests: split args
Here we want args to be splited into individual strings.
2019-05-06 13:02:45 +02:00
Zdenek Kabelac
4ff472b907 tests: drop call of wipefs
wipefs might not be present on test system.
Devices are also already zeroed by cleanup_md_dev
(which 'fakes' missing wipefs eventually)
2019-05-04 19:11:00 +02:00