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When using lvm shell, some structures which are cached in memory may be
reused. This happens for the struct label (a part of lvmcache_info
structure) when lvmetad is used in which case the PV scan is not
done that would normally overwrite these label structures in memory
and making them up-to-date.
This is all consequence of the fact that struct lvmcache_info and
struct label are not always assigned in the same part of the code.
For example, if lvmetad *is not* used, parts of the struct label are
reassigned in label_read fn while struct lvmcache_info is created
elsewhere. No part of the code reused struct label (and its "dev"
field) before calling label_read fn. That's why the real bug is
hidden when using lvm shell without lvmetad.
However, with lvmetad and lvm shell, the situation is a bit different.
The label_read fn is not called if lvmetad *is* used, hence the
struct label may have ended up not initialized properly.
There was missing assignment for the dev field in struct label
in _text_pv_write fn which caused this problem to appear in
lvm shell with lvmetad, for example:
Before this patch:
lvm> pvcreate /dev/sda
Physical volume "/dev/sda" successfully created
lvm> pvs /dev/sda
PV VG Fmt Attr PSize PFree
unknown device lvm2 --- 128.00m 128.00m
With this patch applied:
lvm> pvcreate /dev/sda
Physical volume "/dev/sda" successfully created
lvm> pvs /dev/sda
PV VG Fmt Attr PSize PFree
/dev/sda lvm2 --- 128.00m 128.00m
Also, this problem had not appeared before changes introduced
by commits e1a63905d1 through
3a6f91d713 which, among other
things, added proper label field type reporting. Before, label
reporting was the same as using struct physical_volume which
has its own dev field assigned and so this problem was not exposed.
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.
This applies the same rule/logic to dlm VGs that has always
existed for sanlock VGs. Allowing a dlm VG to be removed
while its lockspace was still running on other hosts largely
worked, but there were difficult problems if another VG with
the same name was recreated. Forcing the VG lockspace to
be stopped, gives both sanlock and dlm VGs the same behavior.
The code was expecting the wrong return value from
compare_config, which returns 0 when equal.
This is a problem for a lockd VG using multiple PVs
when the VG needs to be rescanned.
Certain stacks of cached LVs may have unexpected consequences.
So add a warning function called when LV is cached to detect
such caces and WARN user about them - the best we could do ATM.
When we insert layer we also move status flag-bits for certain LV types,
so internal volume_group structure remains consistent.
(Perhaps it's misuse of 'insert_layer' function and we should have
another similar function for this.)
Basically we aim to maintain the same state as after reading fresh
metadata out of volume group.
Currently we when i.e. cache 'raid' LV - this should transfer 'raidLV' flag
to _corigin LV and cache is no longer a raid.
TODO: bits for stacked devices needs more exact rules.
Add a new arg to lockd_start_vg() that indicates
it is being called for a new lockd VG, so that
lvmlockd knows the lockspace being started is new.
(Will be used by a following commit.)
Ensure make clean cleans any left-over file from their previous
location so they are not in conflict with new ones.
Also hide error message when .commands file is not present.
The regex filter (controlled by devices/filter lvm.conf setting) was
evaluated as the very last filter. However, this is not optimal when
it comes to restricting disk access - users define devices/filter
as well as devices/global_filter to avoid this.
The devices/global_filter is already positioned at the beginning of the
filter chain. We need to do the same for devices/filter.
Filter chains before this patch:
A: when lvmetad is not used:
persistent_filter -> sysfs_filter -> global_regex_filter ->
type_filter -> usable->filter -> mpath_component_filter ->
partition_filter -> md_component_filter -> fw_raid_filter ->
regex_filter
B: when lvmetad is used:
B1: to update lvmetad:
sysfs_filter -> global_regex_filter -> type_filter ->
usable_filter -> mpath_component_filter -> partition_filter ->
md_component_filter -> fw_raid_filter
B2: to retrieve info from lvmetad:
persistent_filter -> usable_filter -> regex_filter
From the chain list above we can see that particularly in case when
lvmetad is not used, the regex filter is the very last one that is
processed. If lvmetad is used, it doesn't matter much as there's
the global_regex_filter which is used instead when updating lvmetad
and when retrieving info from lvmetad, putting regex_filter in front
of usable_filter wouldn't change much since usabled_filter is not
reading disks directly.
This patch puts the regex filter to the front even in case lvmetad
is not used, hence reinstating the state as it was before commit
a7be3b12df (which moved the regex_filter
position in the chain). Still, the arguments for the commit
a7be3b12df still apply and they're
still satisfied since component filters (MD, mpath...) are evaluated
first just before updating lvmetad.
So with this patch, we end up with:
A: when lvmetad is not used:
persistent_filter -> sysfs_filter -> global_regex_filter ->
regex_filter -> type_filter -> usable->filter ->
mpath_component_filter -> partition_filter ->
md_component_filter -> fw_raid_filter
B: when lvmetad is used:
B1: to update lvmetad:
sysfs_filter -> global_regex_filter -> type_filter ->
usable_filter -> mpath_component_filter -> partition_filter ->
md_component_filter -> fw_raid_filter
B2: to retrieve info from lvmetad:
persistent_filter -> regex_filter -> usable_filter
This way, specifying the regex_filter in non-lvmetad case causes
the devices to be filtered based on regex first before processing
any other filters which can access disks (like md_component_filter).
This patch also streamlines the code for better readability.
Relocate generated configure.h and lvm-version.h outside
of compilable .c source tree.
The reason is behind - when compiling in builddir != srcdir
the generated file in lib/misc/configure.h was used for all compiled
source file except ones located in lib/misc dir - those would have used
configure.h file located in this dir - if there have existed one (i.e.
from some other build)
This problem was only visible, when srcdir == buildir was used before
trying to use srcdri != builddir (as configure.h appeared then in
srcdir).
As part of fix that came with cf700151eb,
I forgot to add the check whether the result of stat was successful or
not. This bug caused uninitialized buffer to be used for entries
from .cache file which are no longer valid.
This bug may have caused these uninitialized values to be used further,
for example (see the unreal (2567,590944) representing major:minor
pair):
$ pvs
/dev/abc: stat failed: No such file or directory
Path /dev/abc no longer valid for device(2567,590944)
PV VG Fmt Attr PSize PFree
/dev/mapper/test lvm2 --- 104.00m 104.00m
/dev/vda2 rhel lvm2 a-- 9.51g 0
Since we may easily get blocked when checking for percentage
of thin-pool - do not flush and just show current values.
This avoids holding VG locked when pool is overfilled.
Try to detect thin-pool which my block lvm2 command from furher
processing (i.e. lvextend).
Check if pool is read-only or out-of-space and in this case thins
will skipped from being scanned (so user may miss some PVs located
on thin volumes).
Fix regression introduced with commit:
2fc126b00d
This commit has moved pv_min_size() test in front
of device_is_usable(). However pv_min_size needs to open device,
so it may have actually get blocked.
So restore the original order and first validate
dm device to be usable for open.
It's worth to note that such check is not 'race-free',
but it usually eliminates 99.99% of problems ;).
Print [source:handler] in filters' debug messages only if external
device info source other than "none" is used.
$ lvmconfig --type full devices/external_device_info_source
external_device_info_source="none
Before this patch (from the -vvvv log):
filters/filter-usable.c:47 /dev/mapper/test: Skipping: Too small to hold a PV [none:(nil)]
filters/filter-md.c:33 /dev/sdb: Skipping md component device [none:(nil)]
filters/filter-partitioned.c:25 /dev/vda: Skipping: Partition table signature found [none:(nil)]
With this patch applied:
filters/filter-usable.c:44 /dev/mapper/test: Skipping: Too small to hold a PV
filters/filter-md.c:35 /dev/sdb: Skipping md component device
filters/filter-partitioned.c:27 /dev/vda: Skipping: Partition table signature found
This was only used to return two flags indicating specific
reasons for a lock failure so that a more specific error
message could be printed by the command (lockspace had been
stopped, or lockspace had an error starting.)
Remove the list, given its limited usefulness, the fact it
would easily become inaccurate, and the fact it was causing
misleading error messages. The error conditions it was meant
to help could be reported differently.
Previously, a command would only rescan a lockd VG
when lvmetad returned the "vg_invalid" flag indicating
that the cached copy was invalid (which is done by
lvmlockd.) This is still the only usual reason for
rescanning a lockd VG, but two new special cases are
added where we also do the rescan:
. When the --shared option is used to display lockd VGs
from hosts not using lvmlockd. This is the same case
as using --foreign to display foreign VGs, but --shared
was missing the corresponding bits to rescan the VGs.
. When a lockd VG is allowed to be read for displaying
after failing to acquire the lock from lvmlockd. In
this case, the usual mechanism for validating the
cache is missed, so assume the cache would have been
invalidated. (This had been a previous todo item
that was lost during other cleanup.)
These were long-standing todos that were lost track of.
This makes lvmlockd removal steps for dlm VGs closely match
sanlock VGs. Because dlm lockspaces are not required to be
stopped on all hosts before vgremove, there is an extra bit
for dlm lockspaces, where a flag is set in the VG lock lvb
indicating that the VG was removed. If other hosts happen
to use the VG lock they will see this flag and stop their
lockspace.
Remove the existing lock type using the same functions
used to remove the lockd components during vgremove.
This results in a "clean" VG and lvmlockd state after
the vgchange, i.e. no bits left over from previous
lock type.
Since cache-pool actualy keeps info about caching,
display this info for cache-pool LV as well
(matches info for cache LV when cache-pool is asociated with it).
Fix the version export macros to make it possible to export two
different DM_* versions of a symbol: currently it is only possible for a
DM_* symbol to override a symbol in Base. Attempting to export two
symbols at different DM_* version levels (e.g. DM_1_02_104 and
DM_1_02_106) leads to a linker error due to a duplicate symbol
definition.
This is because the DM_EXPORTED_SYMBOL macro makes each exported symbol
the default (@@VERSION):
__asm__(".symver " #func "_v" #ver ", " #func "@@DM_" #ver )
Fix the macro to use a single '@' for a symbols exported in multiple
versions and rename the macros to DM_EXPORT_*:
DM_EXPORT_SYMBOL(func,ver)
DM_EXPORT_SYMBOL_BASE(func,ver)
For functions that have multiple implementations these macros control
symbol export and versioning.
Function definitions that exist in only one version never need to use
these macros.
Backwards compatible implementations must include a version tag of
the form "_v1_02_104" as a suffix to the function name and use the
macro DM_EXPORT_SYMBOL to export the function and bind it to the
specified version string.
Since versioning is only available when compiling with GCC the entire
compatibility version should be enclosed in '#if defined(__GNUC__)',
for example:
int dm_foo(int bar)
{
return bar;
}
#if defined(__GNUC__)
// Backward compatible dm_foo() version 1.02.104
int dm_foo_v1_02_104(void);
int dm_foo_v1_02_104(void)
{
return 0;
}
DM_EXPORT_SYMBOL(dm_foo,1_02_104)
#endif
A prototype for the compatibility version is required as these
functions must not be declared static.
The DM_EXPORT_SYMBOL_BASE macro is only used to export the base
versions of library symbols prior to the introduction of symbol
versioning: it must never be used for new symbols.
This mainly makes the description text use 80 columns.
There are a few minor adjustments to wording to help
the text layout, and a couple minor improvements to
descriptions.
This reverts commit 70db1d523d.
Since we use 'strncpy' even for case where it exactly matches
the buffer size and \0 is not expected to be added there.
Before printing a commented automatic config value,
print a line describing what it is. Otherwise, the
commented value can look like it's a part of an
example preceding it.
Move code which runtime detects settings for cache_policy
out of config dir to cache seg handling code.
Also mark cache_mode as command profilable setting.
Revert back to already existing behavior which has been slightly
modified by a900d150e4.
At the end however it seem to be equal to change TID right with first
metadata write.
Existing code missed handling for 'unused' thin-pool which would
require to also check empty message list for TID==0.
So with the fix we now again preserve 'active' thin-pool volume
when first thin volume is created - this property was lost and caused
problems in cluster, where the lock was hold, but volume was no longer
active on the node.
Another missing part was the proper support for already increased,
but unfinished TID change.
So going back here with existing logic -
TID is increased with first MDA update.
Code allows start with either same TID or (TID-1).
If there are messages, TID must be lower by 1 for sending,
otherwise messages were already posted.
As cache_policy is evaluated in runtime, we no longer should use
CFG_COMMENTED, but have to switch to CFG_UNDEFINED.
So as long as the value is undefined, it's runtime evaluated.
Once it's set - it's always respected (no runtime fallback).
Also fix version of introduced settings to 2.2.128.
If the Linux timerfd interface to POSIX timers is available at compile
time use it for all report interval timekeeping. This gives more
accurate interval timing when the per-interval processing time is less
than the configured interval and simplifies the timestamp bookkeeping
required to keep accurate time.
For systems without timerfd support fall back to the simple usleep based
timer.
Change logic and naming of some internal API functions.
cache_set_mode() and cache_set_policy() both take segment.
cache mode is now correctly 'masked-in'.
If the passed segment is 'cache' segment - it will automatically
try to find 'defaults' according to profiles if the are NOT
specified on command line or they are NOT already set for cache-pool.
These defaults are never set for cache-pool.
Add code to detect available cache features.
Support policy_mq & policy_smq features which might be disabled.
Introduce global_cache_disabled_features_CFG.
Add new profilable configurables:
allocation/cache_policy
allocation/cache_settings
and mark allocation/cache_pool_chunk_size as profilable as well.
Obsolete allocation/cache_pool_cachemode and
introduce new allocation/cache_mode instead.
Rename DEFAULT_CACHE_POOL_POLICY to DEFAULT_CACHE_POLICY.
lvrename should not be done if the LV is active on another host.
This check was mistakenly removed when the code was changed to
use LV uuids in locks rather than LV names.
When vgremove is used to remove multiple VGs in one command,
e.g. vgremove foo bar, the first VG (foo) that is removed
may have held the sanlock global lock. In this case,
do not continue removing further VGs (bar) without the
global lock.
This adds the infrastructure, code paths, error reporting,
etc. to handle storage errors, or storage loss, under the
sanlock leases in a VG that is being used. The loss of
storage means sanlock cannot renew its leases, which means
that the host needs to stop using the shared VG before its
leases expire.
This still requires manually shutting down a VG that has
lost lease storage, e.g. unmounting file systems,
deactivating LVs in the VG. The next step is to
automatically use a command like blkdeactivate to do that.
/lib/log/log.c:88: warning[invalidScanfArgType_int]: %llu in format string (no. 2) requires 'unsigned long long *' but the argument type is 'long long *'.
daemons/lvmlockd/lvmlockd-core.c:791: error[uninitstring]: Dangerous usage of 'version' (strncpy doesn't always null-terminate it).
Use refresh_filters instead of destroy_filters and init_filters
in refresh_toolcontext fn which deals with cmd->initialized.filters
correctly on refresh.
Just shuffle the items and put them into logical groups so it's
visible at first sight what each group contains - it makes it a bit
easier to make heads and tails of the whole cmd_context monster.
When a command is flagged with NO_METADATA_PROCESSING flag, it means
such command does not process any metadata and hence it doens't require
lvmetad, lvmpolld and it can get away with no locking too. These are
mostly simple commands (like lvmconfig/dumpconfig, version, types,
segtypes and other builtin commands that do not process metadata
in any way).
At first, when lvm command is executed, create toolcontext without
initializing connections (lvmetad,lvmpolld) and without initializing
filters (which depend on connections init). Instead, delay this
initialization until we know we need this. That is, until the
lvm_run_command fn is called in which we know what the actual
command to run is and hence we can avoid any connection, filter
or locking initiliazation for commands that would not make use
of it anyway.
For all the other create_toolcontext calls, we keep the original
behaviour - the filters and connections are initialized together
with the toolcontext.
Make it possible to decide whether we want to initialize connections and
filters together with toolcontext creation.
Add "filters" and "connections" fields to struct
cmd_context_initialized_parts and set these in cmd_context.initialized
instance accordingly.
(For now, all create_toolcontext calls do initialize connections and
filters, we'll change that in subsequent patch appropriately.)
Move original lvmetad and lvmpolld initialization code from
_process_config fn to their own functions _init_lvmetad and
_init_lvmpolld (both covered with single _init_connections fn).
Add struct cmd_context_initialized_parts to wrap up information
about which cmd context pieces are initialized and add variable
of this struct type into struct cmd_context.
Also, move existing "config_initialized" variable that was directly
part of cmd_context into the new cmd_context.initialized wrapper.
We'll be adding more items into the struct cmd_context_initialized_parts
with subsequent patches...
This tries harder to avoid creating duplicate global locks in
sanlock VGs by refusing to create a new sanlock VG with a
global lock if other sanlock VGs exist that may have a gl.
vgsummary information contains provisional VG information
that is obtained without holding the VG lock. This info
can be used to lock the VG, and then read it with vg_read().
After the VG is read properly, the vgsummary info should
be verified.
Add the VG lock_type to the vgsummary. It needs to be
known before the VG can be locked and read.
This is a regression introduced by commit
6c0e44d5a2 which changed
the way dev_cache_get fn works - before this patch, when a
device was not found, it fired a full rescan to correct the
cache. However, the change coming with that commit missed
this full_rescan call, causing the lvmcache to still contain
info about PVs which should be filtered now.
Such situation may have happened by coincidence of using
old persistent cache (/etc/lvm/cache/.cache) which does not
reflect the actual state anymore, a device name/symlink which
now points to a device which should be filtered and a fact we
keep info about usable DM devices in .cache no matter what
the filter setting is.
This bug could be hidden though by changes introduced in
commit f1a000a477 as it
calls full_rescan earlier before this problem is hit.
But we need to fix this anyway for the dev_cache_get
to be correct if we happen to use the same code path
again somewhere sometime.
For example, simple reproducer was (before commit
1a000a477558e157532d5f2cd2f9c9139d4f87c):
- /dev/sda contains a PV header with UUID y5PzRD-RBAv-7sBx-V3SP-vDmy-DeSq-GUh65M
- lvm.conf: filter = [ "r|.*|" ]
- rm -f .cache (to start with clean state)
- dmsetup create test --table "0 8388608 linear /dev/sda 0" (8388608 is
just the size of the /dev/sda device I use in the reproducer)
- pvs (this will create .cache file which contains
"/dev/disk/by-id/lvm-pv-uuid-y5PzRD-RBAv-7sBx-V3SP-vDmy-DeSq-GUh65M"
as well as "/dev/mapper/test" and the target node "/dev/dm-1" - all the
usable DM mappings (and their symlinks) get into the .cache file even
though the filter "is set to "ignore all" - we do this - so far it's OK)
- dmsetup remove test (so we end up with /dev/disk/by-id/lvm-pv-uuid-...
pointing to the /dev/sda now since it's the underlying device
containing the actual PV header)
- now calling "pvs" with such .cache file and we get:
$ pvs
PV VG Fmt Attr PSize PFree
/dev/disk/by-id/lvm-pv-uuid-y5PzRD-RBAv-7sBx-V3SP-vDmy-DeSq-GUh65M vg lvm2 a-- 4.00g 0
Even though we have set filter = [ "r|.*|" ] in the lvm.conf file!
Moved out from lib/display and a little documentation added.
It's tuned to LVM's requirements historically and its behaviour
might not always be what you would expect.
There is no longer an "enable" option for the global lock,
so remove the bit of code that was checking for it. It
was an optional variation anyway, and not one that was likely
to be used.
Also update the corresponding comment describing global lock
creation.
pvscan autoactivation does not work for lockd VGs because
lock start is needed on a lockd VG before locking can be
done for it. Add a check to skip the attempt at autoactivate
rather than calling it, knowing it will fail.
Add a comment explaining why pvscan --cache works fine for
lockd VGs without locks, and why autoactivate is not done.
The CFG_SECTION_NO_CHECK flag can be used to mark a section
and its whole subtree as containing settings where checks
won't be made (lvmconfig --validate).
These are setting where we don't know the names and and type
in advance and they're recognized in runtime. As we don't know
the type and name in advance, we can't do any checks here
of course.
Use this flag with great care as it disables config checks
for the whole config subtree found under such section.
This flag is going to be used by subsequent patches from
Zdenek to support some cache settings...
Comply with the rules we have for log_error and log_warn...
$ pvcreate /dev/sda1
Failed to get offset of the xfs_external_log signature on /dev/sda1.
1 existing signature left on the device.
Aborting pvcreate on /dev/sda1.
$ pvcreate /dev/sda1 --force
WARNING: Failed to get offset of the xfs_external_log signature on /dev/sda1.
Physical volume "/dev/sda1" successfully created
libblkid may return the list of signatures found, but it may not
provide offset and size for each signature detected. This may
happen in case signatures are mixed up or there are more, possibly
overlapping, signatures found.
Make lvm commands pass if such situation happens and we're using
--force (or any stronger force method).
For example:
$ pvcreate /dev/sda1
Failed to get offset of the xfs_external_log signature on /dev/sda1.
1 existing signature left on the device.
Aborting pvcreate on /dev/sda1.
$ pvcreate --force /dev/sda1
Failed to get offset of the xfs_external_log signature on /dev/sda1.
Physical volume "/dev/sda1" successfully created
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.
When lvmlockd is compiled without support for one of the
lock managers (sanlock or dlm), and a command tries to use
one of them, explain that in the error message.
When lvm is built without lvmlockd support, vgcreate using a
shared lock type would succeed and create a local VG (the
--shared option was effectively ignored). Make it fail.
Fix the same issue when using vgchange to change a VG to a
shared lock type.
Make the error messages consistent.
A segfault was reported when extending an LV with a smaller number of
stripes than originally used. Under unusual circumstances, the cling
detection code could successfully find a match against the excess
stripe positions and think it had finished prematurely leading to an
allocation being pursued with a length of zero.
Rename ix_offset to num_positional_areas and move it to struct
alloc_state so that _is_condition() can obtain access to it.
In _is_condition(), areas_size can no longer be assumed to match the
number of positional slots being filled so check this newly-exposed
num_positional_areas directly instead. If the slot is outside the
range we are trying to fill, just ignore the match for now.
(Also note that the code still only performs cling detection against
the first segment of the LV.)
Replace misleading "not found" in the log message when
devices/preferred_names is set to empty array:
Really not found:
device/dev-cache.c:689 devices/preferred_names not found in config: using built-in preferences
Found, but empty:
config/config.c:1431 Setting devices/preferred_names to preferred_names = [ ]
device/dev-cache.c:689 devices/preferred_names is empty: using built-in preferences
Commit 7e728fe1a1 added a log call
directly in find_config_tree_array when defaults are used.
This patch also adds the log for the value which is found in
existing configuration and for which defaults are not used.
For example:
Defaults used:
config/config.c:1428 devices/scan not found in config: defaulting to scan = [ "/dev" ]
Value defined in configuration used:
config/config.c:1431 Setting devices/scan to scan = [ "/dev", "/mydev", "/abc" ]
This makes the logging consistent with the other find_config_tree_* functions.
Policy name has to be always defined.
Capture it as an internal error before write.
When reading metadata without defined policy name, use default defined policy.
TODO: Unsure, but it might have to be actually always 'mq' in this case.
Keep policy name separate from policy settings and avoid
to mangling and demangling this string from same config tree.
Ensure policy_name is always defined.
Use find_config_tree_array for all config arrays. Also, add
INTERNAL_ERROR in case there should have been at least default
value defined for a setting but it was not returned for some
reason (either config_settings.h misconfiguration or other config
tree error printed by functions called by find_config_tree_array).
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.
Require global/{thin,cache}_{check,repair}_options to be always defined.
If not defined directly by user in the configuration and if there's no
concrete default option to use, make "" (empty string) the default one -
it's then clearly visible in the "lvmconfig --type default" (and
generated lvm.conf) and also it makes its handling in the code more
straightforward so we don't need to handle undefined values.
This means, if there are no default values for these settings defined,
we end up with this generated now:
{thin,cache}_{check,repair}_options = [ "" ]
So the value is never undefined and if it is, it's an error.
(The cache_repair_options is actually not used in the code at the moment,
but once the code using this setting is in, it will follow the same logic
as used for thin_repair_options.)
When --nolocking is used (by vgs, lvs, pvs):
. don't use lvmlockd at all (set use_lvmlockd to 0)
. allow lockd VGs to be read
When --readonly is used (by vgs, lvs, pvs, vgdisplay, lvdisplay,
pvdisplay, lvmdiskscan, lvscan, pvscan, vgcfgbackup):
. skip actual lvmlockd locking calls
. allow lockd VGs to be read
. check that only shared gl/vg locks are being requested
(even though the actually locking is being skipped)
. check that no LV locks are requested, because no LVs
should be activated or used in readonly mode
. disable using lvmetad so VGs are read from disk
It is important to note the limited commands that accept
the --nolocking and --readonly options, i.e. no commands
that change/write a VG or change/activate LVs accept these
options, only commands that read VGs.
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.
log_warn was added recently because no known code used
the given condition, but running pvcreate on an existing
PV uses this case, and should not produce a warning.
Put the change from commit #10d27998b3d2f6100e9e29e83d1d99948c55875f
back so we have working tree again for now. This code needs a bit of
a cleanup to return proper return value to check...
lib/format1/import-export.c:167: var_deref_op: Dereferencing null pointer "vg->lvm1_system_id"
lib/cache/lvmetad.c:1023: var_deref_op: Dereferencing null pointer "this"
daemons/lvmlockd/lvmlockd-core.c:2659: check_after_deref: Null-checking "act" suggests that it may be null, but it has already been dereferenced on all paths leading to the check
/daemons/lvmetad/lvmetad-core.c:1024: check_after_deref: Null-checking "pvmeta" suggests that it may be null, but it has already been dereferenced on all paths leading to the check
lib/log/log.c:115: leaked_storage: Variable "st" going out of scope leaks the storage it points to
daemons/lvmpolld/lvmpolld-core.c:573: leaked_storage: Variable "cmdargv" going out of scope leaks the storage it points to
daemons/lvmlockd/lvmlockd-core.c:5341: leaked_handle: Handle variable "fd" going out of scope leaks the handle
daemons/lvmlockd/lvmlockctl.c:575: overwrite_var: Overwriting "able_vg_name" in "able_vg_name = strdup(optarg)" leaks the storage that "able_vg_name" points to
daemons/lvmlockd/lvmlockctl.c:571: overwrite_var: Overwriting "able_vg_name" in "able_vg_name = strdup(optarg)" leaks the storage that "able_vg_name" points to
daemons/lvmlockd/lvmlockctl.c:385: leaked_handle: Handle variable "s" going out of scope leaks the handle
Before, we used general find_config_tree_node function to retrieve
array values. This had a downside where if the node was not found,
we had to insert default values directly in-situ after the
find_config_tree_node call. This way, we had two copies of default
values - one in config_settings.h and the other one directly in the
code where we found out that find_config_tree_node returned NULL and
hence we needed to fall back to defaults.
With separate find_config_tree_array used for array config values,
we keep all the defaults centrally in config_settings.h because
the new find_config_tree_array automatically returns these defaults
if it can't find any value set in the configuration.
This patch just makes the behaviour exactly the same for arrays as
for any other non-array type where we call find_config_tree_<type>
already, hence making the internal interface for handling array
values consistent with the rest of the config types.
including the allow_override_lock_modes setting.
It was not possible to override default lock modes any longer,
since the command line options had already been removed.
A mechanism will probably be required later that puts part of
this back.
Existing messaging intarface for thin-pool has a few 'weak' points:
* Message were posted with each 'resume' operation, thus not allowing
activation of thin-pool with the existing state.
* Acceleration skipped suspend step has not worked in cluster,
since clvmd resumes only nodes which are suspended (have proper lock
state).
* Resume may fail and code is not really designed to 'fail' in this
phase (generic rule here is resume DOES NOT fail unless something serious
is wrong and lvm2 tool usually doesn't handle recovery path in this case.)
* Full thin-pool suspend happened, when taken a thin-volume snapshot.
With this patch the new method relocates message passing into suspend
state.
This has a few drawbacks with current API, but overal it performs
better and gives are more posibilities to deal with errors.
Patch introduces a new logic for 'origin-only' suspend of thin-pool and
this also relates to thin-volume when taking snapshot.
When suspend_origin_only operation is invoked on a pool with
queued messages then only those messages are posted to thin-pool and
actual suspend of thin pool and data and metadata volume is skipped.
This makes taking a snapshot of thin-volume lighter operation and
avoids blocking of other unrelated active thin volumes.
Also fail now happens in 'suspend' state where the 'Fail' is more expected
and it is better handled through error paths.
Activation of thin-pool is now not sending any message and leaves upto a tool
to decided later how to finish unfinished double-commit transaction.
Problem which needs some API improvements relates to the lvm2 tree
construction. For the suspend tree we do not add target table line
into the tree, but only a device is inserted into a tree.
Current mechanism to attach messages for thin-pool requires the libdm
to know about thin-pool target, so lvm2 currently takes assumption, node
is really a thin-pool and fills in the table line for this node (which
should be ensured by the PRELOAD phase, but it's a misuse of internal API)
we would possibly need to be able to attach message to 'any' node.
Other thing to notice - current messaging interface in thin-pool
target requires to suspend thin volume origin first and then send
a create message, but this could not have any 'nice' solution on lvm2
side and IMHO we should introduce something like 'create_after_resume'
message.
Patch also changes the moment, where lvm2 transaction id is increased.
Now it happens only after successful finish of kernel transaction id
change. This change was needed to handle properly activation of pool,
which is in the middle of unfinished transaction, and also this corrects
usage of thin-pool by external apps like Docker.
Recognize date and time specification within selection criteria
that is formulated in a more free-form way besides to the original
basic YYYY-MM-DD HH:MM format that libdevmapper supports.
Currently, this free-form format is recognized for lv_time field.
Users are able to use expressions from this set:
- weekday names ("Sunday" - "Saturday" or abbreviated as "Sun" - "Sat")
- labels for points in time ("noon", "midnight")
- labels for a day relative to current day ("today", "yesterday")
- points back in time with relative offset from today (N is a number)
( "N" "seconds"/"minutes"/"hours"/"days"/"weeks"/"years" "ago")
( "N" "secs"/"mins"/"hrs" ... "ago")
( "N" "s"/"m"/"h" ... "ago")
- time specification either in hh:mm:ss format or with AM/PM suffixes
- month names ("January" - "December" or abbreviated as "Jan" - "Dec")
For example:
$ date
Fri Jul 3 10:11:13 CEST 2015
$ lvmconfig --type full report/time_format
time_format="%a %Y-%m-%d %T %z %Z [%s]"
$ lvs
LV VG Time
lvol0 vg Fri 2014-08-22 21:25:41 +0200 CEST [1408735541]
lvol2 vg Sun 2015-04-26 14:52:20 +0200 CEST [1430052740]
root fedora Wed 2015-05-27 08:09:21 +0200 CEST [1432706961]
swap fedora Wed 2015-05-27 08:09:21 +0200 CEST [1432706961]
lvol1 vg Tue 2015-06-30 03:25:43 +0200 CEST [1435627543]
lvol3 vg Tue 2015-06-30 14:52:23 +0200 CEST [1435668743]
lvol6 vg Wed 2015-07-01 13:35:56 +0200 CEST [1435750556]
lvol4 vg Thu 2015-07-02 12:12:02 +0200 CEST [1435831922]
lvol5 vg Thu 2015-07-02 14:30:32 +0200 CEST [1435840232]
$ lvs -S 'time=yesterday'
LV VG Time
lvol4 vg Thu 2015-07-02 12:12:02 +0200 CEST [1435831922]
lvol5 vg Thu 2015-07-02 14:30:32 +0200 CEST [1435840232]
$ lvs -S 'time since "June 30"'
LV VG Time
lvol1 vg Tue 2015-06-30 03:25:43 +0200 CEST [1435627543]
lvol3 vg Tue 2015-06-30 14:52:23 +0200 CEST [1435668743]
lvol6 vg Wed 2015-07-01 13:35:56 +0200 CEST [1435750556]
lvol4 vg Thu 2015-07-02 12:12:02 +0200 CEST [1435831922]
lvol5 vg Thu 2015-07-02 14:30:32 +0200 CEST [1435840232]
$ lvs -S 'time since "noon June 30"'
LV VG Time
lvol3 vg Tue 2015-06-30 14:52:23 +0200 CEST [1435668743]
lvol6 vg Wed 2015-07-01 13:35:56 +0200 CEST [1435750556]
lvol4 vg Thu 2015-07-02 12:12:02 +0200 CEST [1435831922]
lvol5 vg Thu 2015-07-02 14:30:32 +0200 CEST [1435840232]
$ lvs -S 'time since "2 July 9AM"'
LV VG Time
lvol4 vg Thu 2015-07-02 12:12:02 +0200 CEST [1435831922]
lvol5 vg Thu 2015-07-02 14:30:32 +0200 CEST [1435840232]
$ lvs -S 'time since "2 July 1PM"'
LV VG Time
lvol5 vg Thu 2015-07-02 14:30:32 +0200 CEST [1435840232]
...and so on.
Wire the dm_report_reserved_handler instance call in reporting/selection
infrastructure to handle reserved value actions (currently only
DM_REPORT_RESERVED_PARSE_FUZZY_NAME and DM_REPORT_RESERVED_GET_DYNAMIC_VALUE
actions).
With fuzzy names we mean the names for which it's hard or even impossible
to enumerate all possible variations of the name - the name needs to
be evaluated. An example of fuzzy name is a name which has a base
(substring) which matches and it can contain arbitrary variations
around this base. We can cover human language better with fuzzy
names as people may use several different names (or sentences) to
denote the same thing.
With dynamic values we mean the values which are not constants
and they need to be evaluated in runtime. An example of dynamic
value is a value which depends on current system state (e.g. time,
current configuration or any other state which may change and it
needs runtime evaluation).
There's a handler that can be registered with reporting/selection
using dm_report_reserved_handler instance. This is a central point
in which the computation/evaluation happens when processing reserved
values. Currently, there are two actions declared:
DM_REPORT_RESERVED_PARSE_FUZZY_NAME
(translates fuzzy name into canonical name)
DM_REPORT_RESERVED_GET_DYNAMIC_VALUE
(gets value for canonical name)
The handler is then registered as value in struct
dm_report_reserved_value (see explaining comments besided
the struct dm_report_reserved_value in libdevmapper.h).
Also, this patch provides support for simple caching of values
used during report/selection via dm_report_value_cache_{set,get}.
This is supposed to be used mainly in the dm_report_reserved_handler
instances to save values among calls so all the handler calls work
with the same base value used in computation/evaluation and/or
possibly to save resources if the evaluation is more time-consuming.
The cache is attached to the dm_report handle and so the cache is
dropped one dm_report is dropped.
dm_snprintf() returns upon success the number of characters printed
(excluding the null byte used to end output to strings).
So add extra byte to preserve \0.
This fixes regression when displaying more then a single lv name.
This patch adds support for time values used in reporting fields.
The raw values are always stored as number of seconds since epoch.
The support that comes with this patch is the basic one which allows
only for recognition of strictly formatted date and time in selection
criteria (the format follows a subset of formats defined by ISO 8601):
date time timezone
date:
YYYY-MM-DD (or shortly YYYYMMDD)
YYYY-MM (shortly YYYYMM), auto DD=1
YYYY, auto MM=01 and DD=01
time:
hh:mm:ss (or shortly hhmmss)
hh:mm (or shortly hhmm), auto ss=0
hh (or shortly hh), auto mm=0, auto ss=0
timezone (always with + or - sign):
+hh:mm or -hh:mm (or shortly +hhmm or -hhmm)
+hh or -hh
Or directly the time (number of seconds) since Epoch (1970-01-01 00:00:00 UTC)
when the number value is prefixed by "@":
@number_of_seconds_since_epoch
This patch also adds aliases for comparison operators
used together with time values which are more intuitive
to use:
since (as alias for >=)
after (as alias for >)
until (as alias for <=)
before (as alias for <)
For example:
$ lvmconfig --type full report/time_format
time_format="%Y-%m-%d %T %z %Z [%s]"
$ lvs -o name,time vg
LV Time
lvol0 2015-06-28 21:25:41 +0200 CEST [1435519541]
lvol1 2015-06-30 03:25:43 +0200 CEST [1435627543]
lvol2 2015-04-26 14:52:20 +0200 CEST [1430052740]
lvol3 2015-06-30 14:52:23 +0200 CEST [1435668743]
$ lvs vg -o name,time -S 'time since "2015-04-26 15:00" && time until "2015-06-30"'
LV Time
lvol0 2015-06-28 21:25:41 +0200 CEST [1435519541]
lvol1 2015-06-30 03:25:43 +0200 CEST [1435627543]
lvol3 2015-06-30 14:52:23 +0200 CEST [1435668743]
$ lvs vg -o name,time -S 'time since "2015-04-26 15:00" && time until "2015-06-30 6:00"'
LV Time
lvol0 2015-06-28 21:25:41 +0200 CEST [1435519541]
lvol1 2015-06-30 03:25:43 +0200 CEST [1435627543]
$ lvs vg -o name,time -S 'time since @1435519541'
LV Time
lvol0 2015-06-28 21:25:41 +0200 CEST [1435519541]
lvol1 2015-06-30 03:25:43 +0200 CEST [1435627543]
lvol3 2015-06-30 14:52:23 +0200 CEST [1435668743]
This is basic time recognition support that is directly a part of
libdevmapper. Recognition of more free-form expressions will be a
part of subsequent patches.
Just like we have DEFAULT_USE_LVMETAD (or DEFUALT_USE_LVMPOLLD), use
fallback_to_lvm1=1 lvm.conf setting if we configured lvm2 with
--enable-lvm1-fallback and use fallback_to_lvm1=0 otherwise.
Also, generate proper lvm.conf.in with unconfigured value.
This patch allows for registration and recognition of reserved
values which are ranges, so they're composed of two values actually
to denote the lower and upper bound for the range (stored as an array
with exactly two items to define the boundaries).
Also, this patch allows for flagging reserved values as named-only
which means that such values are not strictly reserved. The strictly
reserved values are reserved values as used before this patch.
Distinction between strictly-reserved and named-only values
is clearly visible with comparisons. Normally, strictly reserved
value is not accounted for if we do "greater than" or "lower than"
comparisons, for example:
1 2 3 ....
|
abc
- we have "abc" as reserved value for field with value "2"
- the value reported for the field is "abc" (or "2", it doesn't matter here)
- the selection we're processing is -S 'field < abc'
- the result of the selection gives nothing as "abc" is strictly
reserved value (bound to "2") and there's no order defined for
it and it would only match if we directly compared the value
(so -S 'field = abc' would match)
With named-only values, the "abc" is named-only value for "2",
so selection -S 'field < abc" is the same as using -S 'field < 2'.
The "abc" is just an alias for some value so the value or its
assigned name can be used equally in selection criteria.
Make it possible to define format for time that is displayed.
The way the format is defined is equal to the way that is used
for strftime function, although not all formatting options as
used in strftime are available for LVM2 - the set is restricted
(e.g. we do not allow newline to be printed). The lvm.conf
comments contain the whole list that LVM2 accepts for time format
together with brief description (copied from strftime man page).
For example:
(defaults used - the format is the same as used before this patch)
$ lvs -o+time vg/lvol0 vg/lvol1
LV VG Attr LSize Time
lvol0 vg -wi-a----- 4.00m 2015-06-25 16:18:34 +0200
lvol1 vg -wi-a----- 4.00m 2015-06-29 09:17:11 +0200
(using 'time_format = "@%s"' in lvm.conf - number of seconds
since the Epoch)
$ lvs -o+time vg/lvol0 vg/lvol1
LV VG Attr LSize Time
lvol0 vg -wi-a----- 4.00m @1435241914
lvol1 vg -wi-a----- 4.00m @1435562231
Do not display settings with undefined default values, but do display
these settings in case the value is defined directly in any part of
the existing config cascade.
For example, the lvmconfig --type current always displays these settings
(as it's somewhere in "current" configuration cascade that makes it defined).
The lvmconfig --type full displays these settings only if it's defined
somewhere in the cascade, but not if default value is used instead
The lvmconfig --type default never displays these settings...
More concrete example - let's have activation/volume_list directly
set in lvm.conf and activation/read_only_volume_list not set.
Both of these settings have *undefined default* values.
$lvmconfig --type full activation/volume_list activation/read_only_volume_list
volume_list="/dev/vg/lv"
(...only volume_list is defined, hence it's printed)
However, the comments will display more info (see also previous commit):
$lvmconfig --type full activation/volume_list activation/read_only_volume_list --withsummary
# Configuration option activation/volume_list.
# Only LVs selected by this list are activated.
# This configuration option does not have a default value defined.
# Value defined in existing configuration has been used for this setting.
volume_list="/dev/vg/lv"
# Configuration option activation/read_only_volume_list.
# LVs in this list are activated in read-only mode.
# This configuration option does not have a default value defined.
Display comment abour value from existing config being used. For example:
$ lvmconfig --type full --withsummary report/compact_output report/buffered
# Configuration option report/compact_output.
# Do not print empty report fields.
# Value defined in existing configuration has been used for this setting.
compact_output=1
# Configuration option report/buffered.
# Buffer report output.
buffered=1
The lvmconfig --type full is actually a combination of --type current
and --type missing together with --mergedconfig options used.
The overall outcome is a configuration tree with settings as LVM sees
it when it looks for the values - that means, if the setting is defined
in some config source (lvm.conf, --config, lvmlocal.conf or any profile
that is used), the setting is used. Otherwise, if the setting is not
defined in any part of the config cascade, the defaults are used.
The --type full displays exactly this final tree with all the values
defined, either coming from configuration tree or from defaults.
Synchronize with udev logic before reusing device as snapshot.
This patch tries to fix the problem with udev, where we manage
to 'active' LV for clearing, then we deactivate such device and
active again as member of 'origin&snapshot' tree all in 1 step.
There needs to be a sync point where udev has time to remove all links,
otherwise we race with scans and we may end-up with mysterious 'free'
links in the system pointing to wrong dm names.
This patch tries to fix failing topology cluster tests..
We shouldn't be adding spaces by default in output as that
may be be used already in scripts and especially for the eval
in shell scripts where spaces are not allowed between key
and value!
Add --withspaces option to lvmconfig for pretty output with
more space in for readability.
It's not an error to define empty values for
{thin,cache}_{check,repair}_options - such empty value means no
options are passed when these external commands are called.
If blkid wiping is possible, than set use_blkid_wiping=1 and
use_blkid_wiping=0 otherwise for its default value. If blkid wiping
is disabled during configure and use_blkid_wiping=1 is set by chance,
it's simply ignored - this patch is just a cleanup that makes it more
obvious for the user (we use similar logic for use_lvmetad and
use_lvmpolld settings).
Default value for lvmetad and lvmpolld has hooks in configure script,
the "lvmconfig --type default --unconfigured" should display:
use_lvmetad = @DEFAULT_USE_LVMETAD@
use_lvmpolld = @DEFAULT_USE_LVMPOLLD@
Note that these settings are not of string type. Recent change (the
DM_CONFIG_VALUE_FMT_STRING_NO_QUOTES formatting flag) makes it
possible to recognize that the setting is not of string type and if
there's unconfigured value defined for it, the enclosing " " is
automatically removed on output.
Do not use "#S" (blank string) as default value as that ends up with
'key = [ "" ]' to be generated which is not what we want in most cases.
Also, fix default values for global/{thin,cache}_{check,repair}_options
and avoid assigning blank values. For example, the thin_check_options
had this set as default value previously:
"#S" DEFAULT_THIN_CHECK_OPTION1 "#S" DEFAULT_THIN_CHECK_OPTION2
If any (or both) of DEFAULT_THIN_CHECK_OPTION* variables was set
to "", we ended up with clumsy default value generated like:
thin_check_options = [ "-q", "" ]
With this patch, we end up with correct:
thin_check_options = [ "-q" ]
or, if all options are undefined:
thin_check_options = [ ]
Which is the correct way to express this.
There are two basic groups of formatting flags (32 bits):
- common ones applicable for all config value types (lower 16 bits)
- type-related formatting flags (higher 16 bits)
With this patch, we initially support four new flags that
modify the the way the config value is displayed:
Common flags:
=============
DM_CONFIG_VALUE_FMT_COMMON_ARRAY - causes array config values
to be enclosed in "[ ]" even if there's only one item
(previously, there was no way to recognize an array with one
item and scalar value, hence array values with one member
were always displayed without "[ ]" which libdm accepted
when reading, but it may have been misleading for users)
DM_CONFIG_VALUE_FMT_COMMON_EXTRA_SPACE - causes extra spaces to
be inserted in "key = value" (or key = [ value, value, ... ] in
case of arrays), compared to "key=value" seen on output before.
This makes the output more readable for users.
Type-related flags:
===================
DM_CONFIG_VALUE_FMT_INT_OCTAL - prints integers in octal form with
"0" as a prefix (libdm's config reading code can handle this via
strtol just fine so it's properly recognized as number in octal
form already if there's "0" used as prefix)
DM_CONFIG_VALUE_FMT_STRING_NO_QUOTES - makes it possible to print
strings without enclosing " "
This patch also adds dm_config_value_set_format_flags and
dm_config_value_get_format_flags functions to set and get
these formatting flags.
This is the client side handling of the global_invalid state
added to lvmetad in commit c595b50cec8a6b95c6ac4988912d1412f3cc0237.
The function added here:
. checks if the global state in lvmetad is invalid
. if so, scans disks to update the state in lvmetad
. clears the global_invalid flag in lvmetad
. updates the local udev db to reflect any changes
and update the lvmetad copy after it is reread from disk.
This is the client side handling of the vg_invalid state
added to lvmetad in commit c595b50cec8a6b95c6ac4988912d1412f3cc0237.
Use of display_lvname() in plain log_debug() may accumulate memory in
command context mempool. Use instead small ringbuffer which allows to
store cuple (10 ATM) names so upto 10 full names can be used at one.
We are not keeping full VG/LV names as it may eventually consume larger
amount of RAM resouces if vgname is longer and lots of LVs are in use.
Note: if there would be ever needed for displaing more names at once,
the limit should be raised (e.g. log_debug() would need to print more
then 10 LVs on a single line).
With thin-pool kernel target module 1.13 it's now support usage of
external origin with sizes which are not 'alligned' with chunk size
of thin-pool.
Enable lvm2 support for this and also fix reporting of data_percent
usage for case sizes are not alligned.
Note that this is just a quick fix and it needs more robust fix to
encompass any combination, not just the (old) snapshot one!
This started with this report:
https://bugzilla.redhat.com/show_bug.cgi?id=1219222
If we have devices/ignore_suspended_devices=1 set based on which we
filter out suspended devices as unusable (or if we ignore suspended
devices by force, e.g. during lvconvert called from dmeventd) and
when we have snapshot and snapshot origin devices in the play, we
need to look at their components unerneath (*-real and *-cow) to
check if they're not suspended. If they are, the snapshot/snapshot
origin is not usable as well and hence it needs to be filtered out
by filter-usable.c code which does suspended device filtering.
Not going into much details here, more details are in the bugzilla
mentioned above. However, this is a quick fix since snapshot
and this exact situation is not the only one. So this is
something that needs to be revisited and fixed properly
with full dm tree and checking the whole stack to state
whether the device at the very top is usable or not.
This patch fixes segfault which was caused by incorrectly marking some
settings CFG_DEFAULT_COMMENTED instead of CFG_DEFAULT_UNDEFINED - the
ones which have NULL default value, hence they're really undefined.
A regression caused by a98ceceb1d.
For example:
$ lvmconfig log/file
file="/a"
Before this patch:
$ lvmconfig --type diff
Segmentation fault (core dumped)
With this patch applied:
$ lvmconfig --type diff
log {
file="/a"
}
The same applies for these settings:
log/activate_file
global/library_dir
global/system_id_file
<disk_area>/disk_area_id
There were also other settings with NULL default value and marked as
CFG_DEFAULT_COMMENTED instead of CFG_DEFAULT_UNDEFINED, but they were
cfg_array config settings where the NULL value was not causing segfault
(NULL == empty array).
Just as 'e' means activation with an exclusive lock,
add an 's' to mean activation with a shared lock.
This allows the existing but implicit behavior of '-ay'
of clvm LVs to be specified explicitly. For local VGs,
asy simply means ay, just like aey means ay.
For local VGs, ay == aey == asy
For clvm VGs, ay == asy, aey == aey, asy == asy
