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It's possible for an LVM LV to use a device during activation which
then differs from device which LVM assumes based on metadata later on.
For example, such device mismatch can occur if LVM doesn't have
complete view of devices during activation or if filters are
misbehaving or they're incorrectly set during activation.
This patch adds code that can detect this mismatch by creating
VG UUID and LV UUID index while scanning devices for device cache.
The VG UUID index maps VG UUID to a device list. Each device in the
list has a device layered above as a holder which is an LVM LV device
and for which we know the VG UUID (and similarly for LV UUID index).
We can acquire VG and LV UUID by reading /sys/block/<dm_dev_name>/dm/uuid.
So these indices represent the actual state of PV device use in
the system by LVs and then we compare that to what LVM assumes
based on metadata.
For example:
[0] fedora/~ # lsblk /dev/sdq /dev/sdr /dev/sds /dev/sdt
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdq 65:0 0 104M 0 disk
|-vg-lvol0 253:2 0 200M 0 lvm
`-mpath_dev1 253:3 0 104M 0 mpath
sdr 65:16 0 104M 0 disk
`-mpath_dev1 253:3 0 104M 0 mpath
sds 65:32 0 104M 0 disk
|-vg-lvol0 253:2 0 200M 0 lvm
`-mpath_dev2 253:4 0 104M 0 mpath
sdt 65:48 0 104M 0 disk
`-mpath_dev2 253:4 0 104M 0 mpath
In this case the vg-lvol0 is mapped onto sdq and sds becauset this is
what was available and seen during activation. Then later on, sdr and
sdt appeared and mpath devices were created out of sdq+sdr (mpath_dev1)
and sds+sdt (mpath_dev2). Now, LVM assumes (correctly) that mpath_dev1
and mpath_dev2 are the PVs that should be used, not the mpath
components (sdq/sdr, sds/sdt).
[0] fedora/~ # pvs
Found duplicate PV xSUix1GJ2SK82ACFuKzFLAQi8xMfFxnO: using /dev/mapper/mpath_dev1 not /dev/sdq
Using duplicate PV /dev/mapper/mpath_dev1 from subsystem DM, replacing /dev/sdq
Found duplicate PV MvHyMVabtSqr33AbkUrobq1LjP8oiTRm: using /dev/mapper/mpath_dev2 not /dev/sds
Using duplicate PV /dev/mapper/mpath_dev2 from subsystem DM, ignoring /dev/sds
WARNING: Device mismatch detected for vg/lvol0 which is accessing /dev/sdq, /dev/sds instead of /dev/mapper/mpath_dev1, /dev/mapper/mpath_dev2.
PV VG Fmt Attr PSize PFree
/dev/mapper/mpath_dev1 vg lvm2 a-- 100.00m 0
/dev/mapper/mpath_dev2 vg lvm2 a-- 100.00m 0
There's a window between doing VG read and checking PV device size
against real device size. If the device is removed in this window,
the dev cache still holds struct device and pv->dev still references
that and that PV is not marked as missing. However, if we're trying
to get size for such device, the open fails because that device
doesn't exists anymore.
We called existing pv_dev_size in _check_pv_dev_sizes fn. But
pv_dev_size assigned a size of 0 if the dev_get_size it called failed
(because the device is gone).
So call the dev_get_size directly and check for the return code
in _check_pv_dev_sizes and go further only if we really know the
device size. This is to avoid confusing warning messages like:
Device /dev/sdd1 has size of 0 sectors which is smaller than corresponding PV size of 31455207 sectors. Was device resized?
One or more devices used as PVs in VG helter_skelter have changed sizes.
When a command modifies a PV or VG, or changes the
activation state of an LV, it will send a dbus
notification when the command is finished. This
can be enabled/disabled with a config setting.
Historical LV is valid as long as there is at least one live LV among
its ancestors. If we find any invalid (dangling) historical LVs, remove
them automatically.
The vg_strip_outdated_historical_lvs iterates over the list of historical LVs
we have and it shoots down the ones which are outdated.
Configuration hook to set the timeout will be in subsequent patch.
When an LV is being removed, we create an instance of
"struct historical_logical_volume" wrapped up in
"struct generic_logical_volume".
All instances of "struct historical_logical_volume" are then recorded in
"historical_lvs" list which is part of "struct volume_group".
The "historical LV" is then interconnected with "live LVs" to
connect a history chain for the live LV.
"pvcreate_each_params" was a temporary name used
to transition from the old "pvcreate_params".
Remove the old pvcreate_params struct and rename the
new pvcreate_each_params struct to pvcreate_params.
Rename various pvcreate_each_params terms to simply
pvcreate_params.
Use the new pvcreate_each_device() function from
toollib, previously added for pvcreate, in place
of the old pvcreate_vol().
This also requires shifting the location where the
lock is acquired for the new VG name. The lock for
the new VG is supposed to be acquired before pvcreate.
This means splitting the vg_lock_newname() out of
vg_create(), and calling vg_lock_newname() directly
before pvcreate, and then calling the remainder of
vg_create() after pvcreate.
The new function vg_lock_and_create() now does
vg_lock_newname() + vg_create(), like the previous
version of vg_create().
The lock on the new VG name is released before the
pvcreate and reacquired after the pvcreate because
pvcreate needs to reset lvmcache, which doesn't work
when locks are held. An exception could likely be
made for the new VG name lock, which would allow
vgcreate to hold the new VG name lock across the
pvcreate step.
This is common code for handling PV create/remove
that can be shared by pvcreate/vgcreate/vgextend/pvremove.
This does not change any commands to use the new code.
- Pull out the hidden equivalent of process_each_pv
into an actual top level process_each_pv.
- Pull the prompts to the top level, and do not
run any prompts while locks are held.
The orphan lock is reacquired after any prompts are
done, and the devices being created are checked for
any change made while the lock was not held.
Previously, pvcreate_vol() was the shared function for
creating a PV for pvcreate, vgcreate, vgextend.
Now, it will be toollib function pvcreate_each_device().
pvcreate_vol() was called effectively as a helper, from
within vgcreate and vgextend code paths.
pvcreate_each_device() will be called at the same level
as other process_each functions.
One of the main problems with pvcreate_vol() is that
it included a hidden equivalent of process_each_pv for
each device being created:
pvcreate_vol() -> _pvcreate_check() ->
find_pv_by_name() -> get_pvs() ->
get_pvs_internal() -> _get_pvs() -> get_vgids() ->
/* equivalent to process_each_pv */
dm_list_iterate_items(vgids)
vg = vg_read_internal()
dm_list_iterate_items(&vg->pvs)
pvcreate_each_device() reorganizes the code so that
each-VG-each-PV loop is done once, and uses the standard
process_each_pv function at the top level of the function.
The vg->pv_write_list contains pv_list structs for which
vg_write() should call pv_write().
The new list will replace vg->pvs_to_write that contains
vg_to_create structs which are used to perform higher-level
pvcreate-related operations. The higher level pvcreate
operations will be moved out of vg_write() to higher levels.
Ask for confirmation when using pvcreate/pvremove on a PV which is
marked as belonging to a VG, just like we do in case of a PV which
belongs to known VG:
$ pvcreate -ff /dev/sda
Really INITIALIZE physical volume "/dev/sda" that is marked as belonging to a VG [y/n]? n
/dev/sda: physical volume not initialized
$ pvremove -ff /dev/sda
Really WIPE LABELS from physical volume "/dev/sda" that is marked as belonging to a VG [y/n]? n
/dev/sda: physical volume label not removed
The host that owns foreign VGs is responsible for fixing up PV_EXT_USED
flag - the same already applies to repairing any inconsistent VG.
This patch also moves the iteration over vg->pvs inside
_check_or_repair_pv_ext fn - it's cleaner this way.
The same check as we already do for orphan PVs, just the other way
round now: if the PV is surely part of some VG and any PV the VG
contains does not have the PV_EXT_USED flag set, repair it.
For example - /dev/sda here is in VG vg and it's incorrectly not
marked as used by PV_EXT_USED flag:
pvs --binary -o pv_ext_vsn,pv_in_use
WARNING: Volume Group vg is not consistent.
WARNING: Repairing Physical Volume /dev/sda that is in Volume Group vg but not marked as used.
PV VG Fmt Attr PSize PFree ExtVsn PInUse
/dev/sda vg lvm2 a-- 124.00m 124.00m 2 1
PV header extension versions:
0 - the original PV without any extensions
1 - bootloader area support added
2 - PV_EXT_USED flag support added
So do the associated checks related to PV_EXT_USED flag only if
PV header extension found is of version 2 and higher.
If we know that the PV is orphan, meaning there's at least one MDA on
that PV which does not reference any VG and at the same time there's
PV_EXT_USED flag set, we're certainly in an inconsistent state and we
need to fix this.
For example, such situation can happen during vgremove/vgreduce if we
removed/reduced the VG, but we haven't written PV headers yet because
vgremove stopped abruptly for whatever reason just before writing new
PV headers with updated state, including PV extension flags (and so the
PV_EXT_USED flag).
However, in case the PV has no MDAs at all, we can't double-check
whether the PV_EXT_USED is correct or not - if that PV is marked
as used, it's either:
- really used (but other disks with MDAs are missing)
- or the error state as described above is hit
User needs to overwrite the PV header directly if it's really clear
the PV having no MDAs does not belong to any VG and at the same time
it's still marked as being in use (pvcreate -ff <dev_name> will fix this).
For example - /dev/sda here has 1 MDA, orphan and is incorrectly marked
with PV_EXT_USED flag:
$ pvs --binary -o+pv_in_use
WARNING: Found inconsistent standalone Physical Volumes.
WARNING: Repairing flag incorrectly marking Physical Volume /dev/sda as used.
PV VG Fmt Attr PSize PFree InUse
/dev/sda lvm2 --- 128.00m 128.00m 0
Scenario:
$ pvcreate /dev/sda
Physical volume "/dev/sda" successfully created
We're adding the PV to a VG.
Before this patch:
$ vgcreate vg /dev/sda
Physical volume "/dev/sda" successfully created
Volume group "vg" successfully created
With this path applied:
$ vgcreate vg /dev/sda
Volume group "vg" successfully created
...and verbose log containing: "Physical volume "/dev/sda" successfully written"
Make sure we won't use a PV that is already marked as used. Normally,
VG metadata would stop us from doing that, but we can run into a
situation where such metadata is missing because PVs with MDAs
are missing and the PVs left are the ones with 0 MDAs.
(/dev/sda in this example has 0 MDAs and it belongs to a VG,
but other PVs with MDA are missing)
$ pvs -o pv_name,pv_mda_count /dev/sda
PV #PMda
/dev/sda 0
$ pvcreate /dev/sda
PV '/dev/sda' is marked as belonging to a VG but its metadata is missing.
Can't initialize PV '/dev/sda' without -ff.
$ pvchange -u /dev/sda
PV '/dev/sda' is marked as belonging to a VG but its metadata is missing.
Can't change PV '/dev/sda' without -ff.
Physical volume /dev/sda not changed
0 physical volumes changed / 1 physical volume not changed
$ pvremove /dev/sda
PV '/dev/sda' is marked as belonging to a VG but its metadata is missing.
(If you are certain you need pvremove, then confirm by using --force twice.)
$ vgcreate vg /dev/sda
Physical volume '/dev/sda' is marked as belonging to a VG but its metadata is missing.
Unable to add physical volume '/dev/sda' to volume group 'vg'.
We'll use this struct in subsequent patches for PVs which should
be rewritten, not just created. So rename struct pv_to_create to
struct pv_to_write for clarity.
The extent size must fits all blocks in 4294967295 sectors
(in 512b units) this is 1/2 KiB less then 2TiB.
So while previous statement 'suggested' 2TiB is still acceptable value,
make it clear it's not.
As now we support any multiples of 128KB as extent size -
values like 2047G will still 'flow-in' otherwise the largest power-of-2
supported value is 1TiB.
With 1TiB user needs 8388608 extents for 8EiB device.
(FYI such device is already unusable with todays glibc-2.22.90-27)
4GiB extent size is currently the smallest extent size which allows
a user to create 8EiB devices (with 2GiB it's less then 8EiB).
TODO: lvm2 may possibly print amount of 'lost/unused space' on a PV,
since using such ridiculously sized extent size may result in huge
space being left unaccessible.
Have commands send lvmlockd the update message
in vg_write instead of vg_commit, so that it's
not done while LVs are suspended. If the vg_write
is not committed, and the seqno sent to lvmlockd
is not used, then lvmlockd can detect this when
the next update uses the same seqno.
Use process_each_vg() to lock and read the old VG,
and then call the main vgrename code.
When real VG names are used (not a UUID in place of the
old name), the command still pre-locks the new name
(when strcmp wants it locked first), before calling
process_each_vg on the old name.
In the case where the old name is replaced with a UUID,
process_each_vg now translates that UUID into the real
VG name, which it locks and reads. In this case, we
cannot do pre-locking to maintain lock ordering because
the old name is unknown. So, in this case the strcmp
based lock ordering is suppressed and the old name is
always locked first. This opens a remote chance for
lock ordering conflict between racing vgrenames between
two names where one or both commands use the UUID.
After recent changes to process_each, vg_read() is usually
given both the vgname and vgid for the intended VG.
However, in some cases vg_read() is given a vgid with
no vgname, or is given a vgname with no vgid.
When given a vgid with no vgname, vg_read() uses lvmcache
to look up the vgname using the vgid. If the vgname is
not found, vg_read() fails.
When given a vgname with no vgid, vg_read() should also
use lvmcache to look up the vgid using the vgname.
If the vgid is not found, vg_read() fails.
If the lvmcache lookup finds multiple vgids for the
vgname, then the lookup fails, causing vg_read() to fail
because the intended VG is uncertain.
Usually, both vgname and vgid for the intended VG are passed
to vg_read(), which means the lvmcache translations
between vgname and vgid are not done.
Unifying terminology.
Since all the metadata in-use are ALWAYS on disk - switch
to terminology committed and precommitted.
Patch has no functional change inside.
We do not won't to 'expose' internals of VG struct.
ATM we use lists to keep all LVs - we may want to switch
to better struct for quicker 'search'.
Since we do not need 'lists' but always actual LV,
switch find_lv_in_vg_by_lvid() to return LV,
and replaces some use case of find_lv_in_vg()
with 'better' working find_lv() which already
returns LV.
Coverity here is a bit 'blind' here and cannot resolve which
code paths are actually able to hit this code path.
(It's using 'statistic' to resolve all possible paths,
and it's not scanning 'individual' code paths.)
This just cleans warns and add 'cheap' tests.
When reading a foreign VG we cannot write it, since
it belongs to another host. When reading a shared VG
we cannot write it because we may not have an ex lock.
(Or we may be reading the shared VG while not using
lvmlockd in which case it's like reading a foreign VG.)
Add the same checks for wiping outdated PVs. We may
read a foreign or shared VG, or see the PVs, while
another host is part way through writing a new version
of the VG to the PVs. This might cause us to think
some of the PVs are outdated. We do not want to
write another host's PVs, especially when we may
wrongly conclude they are outdated.
Running "vgremove -f VG & pvs" results in the pvs
command reporting that the VG is not found or is
inconsistent. If the VG is gone or being removed,
the pvs command should just skip it and not print
errors about it.
"Not found" is because the pvs command created the
list of VGs to process, including VG, then vgremove
removed the VG, then the pvs command came to to read
the VG to process it and did not find it.
An "inconsistent" error could be reported if vgremove
had only partially completed removing VG when pvs did
vg_read on the VG to process it, causing pvs to find
the VG in a partially-removed state.
This fix adds a flag that pvs uses to ignore a VG
that can't be read or is inconsistent.
When a command does a sequence of
vg_write + vg_commit + vg_write + vg_commit,
initialization of non-PV devices happens during the
first vg_write, and does not need to be repeated by
the second vg_write.
When creating a lockd VG, this sequence occurs because
the VG is first created, then the lockd data is created,
then the lockd data is then written to the VG metadata.
The vgchange/lvchange activation commands read the VG, and
don't write it, so they acquire a shared VG lock from lvmlockd.
When other commands fail to acquire a shared VG lock from
lvmlockd, a warning is printed and they continue without it.
(Without it, the VG metadata they display from lvmetad may
not be up to date.)
vgchange/lvchange -a shouldn't continue without the shared
lock for a couple reasons:
. Usually they will just continue on and fail to acquire the
LV locks for activation, so continuing is pointless.
. More importantly, without the sh VG lock, the VG metadata
used by the command may be stale, and the LV locks shown
in the VG metadata may no longer be current. In the
case of sanlock, this would result in odd, unpredictable
errors when lvmlockd doesn't find the expected lock on
disk. In the case of dlm, the invalid LV lock could be
granted for the non-existing LV.
The solution is to not continue after the shared lock fails,
in the same way that a command fails if an exclusive lock fails.
There are two different failure conditions detected in
access_vg_lock_type() that should have different error
messages. This adds another failure flag so the two
cases can be distinguished to avoid printing a misleading
error message.
There are at least a couple instances where
the lock_args check does not work correctly,
(listed in the comment), so disable the
NULL check for lock_args until those are
resolved.
In process_each_{vg,lv,pv} when no vgname args are given,
the first step is to get a list of all vgid/vgname on the
system. This is exactly what lvmetad returns from a
vg_list request. The current code is doing a vg_lookup
on each VG after the vg_list and populating lvmcache with
the info for each VG. These preliminary vg_lookup's are
unnecessary, because they will be done again when the
processing functions call vg_read. This patch eliminates
the initial round of vg_lookup's, which can roughly cut in
half the number of lvmetad requests and save a lot of extra work.
Do not keep dangling LVs if they're removed from the vg->lvs list and
move them to vg->removed_lvs instead (this is actually similar to already
existing vg->removed_pvs list, just it's for LVs now).
Once we have this vg->removed_lvs list indexed so it's possible to
do lookups for LVs quickly, we can remove the LV_REMOVED flag as
that one won't be needed anymore - instead of checking the flag,
we can directly check the vg->removed_lvs list if the LV is present
there or not and to say if the LV is removed or not then. For now,
we don't have this index, but it may be implemented in the future.
Refactor the recent metadata-reading optimisation patches.
Remove the recently-added cache fields from struct labeller
and struct format_instance.
Instead, introduce struct lvmcache_vgsummary to wrap the VG information
that lvmcache holds and add the metadata size and checksum to it.
Allow this VG summary information to be looked up by metadata size +
checksum. Adjust the debug log messages to make it clear when this
shortcut has been successful.
(This changes the optimisation slightly, and might be extendable
further.)
Add struct cached_vg_fmtdata to format-specific vg_read calls to
preserve state alongside the VG across separate calls and indicate
if the details supplied match, avoiding the need to read and
process the VG metadata again.
Since we take a lock inside vg_lock_newname() and we do a full
detection of presence of vgname inside all scanned labels,
there is no point to do this for second time to be sure
there is no such vg.
The only side-effect of such call would be a full validation of
some already exising VG metadata - but that's not the task for
vgcreate when create a new VG.
This call noticable reduces number of scans during 'vgcreate'.
When reading VG mda from multiple PVs - do all the validation only
when mda is seen for the first time and when mda checksum and length
is same just return already existing VG pointer.
(i.e. using 300PVs for a VG would lead to create and destroy 300 config trees....)
Previous versions of lvm will not obey the restrictions
imposed by the new system_id, and would allow such a VG
to be written. So, a VG with a new system_id is further
changed to force previous lvm versions to treat it as
read-only. This is done by removing the WRITE flag from
the metadata status line of these VGs, and putting a new
WRITE_LOCKED flag in the flags line of the metadata.
Versions of lvm that recognize WRITE_LOCKED, also obey the
new system_id. For these lvm versions, WRITE_LOCKED is
identical to WRITE, and the rules associated with matching
system_id's are imposed.
A new VG lock_type field is also added that causes the same
WRITE/WRITE_LOCKED transformation when set. A previous
version of lvm will also see a VG with lock_type as read-only.
Versions of lvm that recognize WRITE_LOCKED, must also obey
the lock_type setting. Until the lock_type feature is added,
lvm will fail to read any VG with lock_type set and report an
error about an unsupported lock_type. Once the lock_type
feature is added, lvm will allow VGs with lock_type to be
used according to the rules imposed by the lock_type.
When both system_id and lock_type settings are removed, a VG
is written with the old WRITE status flag, and without the
new WRITE_LOCKED flag. This allows old versions of lvm to
use the VG as before.
In log messages refer to it as system ID (not System ID).
Do not put quotes around the system_id string when printing.
On the command line use systemid.
In code, metadata, and config files use system_id.
In lvmsystemid refer to the concept/entity as system_id.
The only realistic way for a host to have active LVs in a
foreign VG is if the host's system_id (or system_id_source)
is changed while LVs are active.
In this case, the active LVs produce an warning, and access
to the VG is implicitly allowed (without requiring --foreign.)
This allows the active LVs to be deactivated.
In this case, rescanning PVs for the VG offers no benefit.
It is not possible that rescanning would reveal an LV that
is active but wasn't previously in the VG metadata.
A foreign VG should be silently ignored by a reporting/display
command like 'vgs'. If the reporting/display command specifies
a foreign VG by name on the command line, it should produce an
error message.
Scanning commands pvscan/vgscan/lvscan are always allowed to
read and update caches from all PVs, including those that belong
to foreign VGs.
Other non-report/display/scan commands always ignore a foreign
VG, or report an error if they attempt to use a foreign VG.
vgimport should always invalidate the lvmetad cache because
lvmetad likely holds a pre-vgexported copy of the VG.
(This is unrelated to using foreign VGs; the pre-vgexported
VG may have had no system_id at all.)
When checking whether the system ID permits access to a VG, check for
each permitted situation first, and only then issue the appropriate
error message. Always issue a message for now. (We'll try to
suppress some of those later when the VG concerned wasn't explicitly
requested.)
Add more messages to try to ensure every return code is checked and
every error path (and only an error path) contains a log_error().
Add self-correction to vgchange -c to deal with situations where
the cluster state and system ID state are out-of-sync (e.g. if
old tools were used).
Move the lvm1 sys ID into vg->lvm1_system_id and reenable the #if 0
LVM1 code. Still display the new-style system ID in the same
reporting field, though, as only one can be set.
Add a format feature flag FMT_SYSTEM_ON_PVS for LVM1 and disallow
access to LVM1 VGs if a new-style system ID has been set.
Treat the new vg->system_id as const.
The dev ext source must be reset for the dev_cache_get call
(which evaluates filters), not lvmcache_label_scan - so fix
original commit 727c7ff85d.
Also, add comments in _pvcreate_check fn explaining why
refresh filter and rescan is needed and exactly in which
situations.
Before, we refreshed filters and we did full rescan of devices if
we passed through wiping (wipe_known_signatures fn call). However,
this fn returns success even if no signatures were found and so
nothing was wiped. In this case, it's not necessary to do the
filter refresh/rescan of devices as nothing changed clearly.
This patch exports number of wiped signatures from all the
wiping functions below. The caller (_pvcreate_check) then checks
whether any wiping was done at all and if not, no refresh/rescan
is done, saving some time and resources.
pvcreate code path executes signature wiping if there are any signatures
found on device to prepare the device for PV. When the signature is wiped,
the WATCH udev rule triggers the event which then updates udev database
with fresh info, clearing the old record about previous signature.
However, when we're using udev db as dev-ext source, we'd need to wait
for this WATCH-triggered event. But we can't synchronize against such
events (at least not at this moment). Without this sync, if the code
continues, the device could still be marked as containing the old
signature if reading udev db. This may end up even with the device
to be still filtered, though the signature is already wiped.
This problem is then exposed as (an example with md components):
$ mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda /dev/sdb --run
$ mdadm -S /dev/md0
$ pvcreate -y /dev/sda
Wiping linux_raid_member signature on /dev/sda.
/dev/sda: Couldn't find device. Check your filters?
$ echo $?
5
So we need to temporarily switch off "udev" dev-ext source here
in this part of pvcreate code until we find a way how to sync
with WATCH events.
(This problem does not occur with signature wiping which we do
on newly created LVs since we already handle this properly with
our udev flags - the LV_NOSCAN/LV_TEMPORARY flag. But we can't use
this technique for non-dm devices to keep WATCH rule under control.)
Better than previous patch which changed log_warn to log_error -
we can have multiple MDAs and if one of them fails to be written,
we can still continue with other MDAs if we're in a mode where
we can handle missing PVs - so keep the log_warn for single
failed MDA write as it was before.
However, add log_error with "Failed to write VG <vg_name>." in
case we're not handling missing PVs or no MDA was written at all
during VG write process. This also prevents an internal error in
which the vg_write fails and we're not issuing any other log_error
in vg_write caller or above, so we end up with:
"Internal error: Failed command did not use log_error".
Use log_warn when we are effectively not creating an error -
we 'allowed' inconsistent read for a reason - so it's just warning
level we process inconsistent VG - it's upto caller later to decide
error level of command return value and in case of error it needs
to use log_error then.
Failed recovery provides different (NULL) VG then FAILED_INCONSISTENT.
Mark it with different failure bit - since FAILED_INCONSISTENT is
supposed to contain something 'usable' (thought inconsistent).
Add API call to calculate extents from percentage value.
Size is based in DM_PERCENT_1 units.
(Supporting decimal point number).
This commit is preparing functionality for more global
usage of % with i.e. --size option.
