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When we preload device with smaller size, we avoid its resume,
so later suspend/resume of full device tree my process all
existing in flight bios.
Also update comment and avoid using confusing opposite meaning.
Add:
- support for segment types raid6_{ls,rs,la,ra}_6
(striped raid with dedicated last Q-Syndrome SubLVs)
- conversion support from raid5_{ls,rs,la,ra} to/from raid6_{ls,rs,la,ra}_6
- setting convenient segtypes on conversions from/to raid4/5/6
- related tests to lvconvert-raid-takeover.sh factoring
out _lvcreate,_lvconvert funxtions
Related: rhbz1366296
Add:
- support for segment type raid6_n_6 (striped raid with dedicated last parity/Q-Syndrome SubLVs)
- conversion support from striped/raid0/raid0_meta/raid4 to/from raid6_n_6
- related tests to lvconvert-raid-takeover.sh
Related: rhbz1366296
Add:
- support for segment type raid5_n (striped raid with dedicated last parity SubLVs)
- conversion support from striped/raid0/raid0_meta/raid4 to/from raid5_n
- related tests to lvconvert-raid-takeover.sh
Related: rhbz1366296
Add a call to update the regions corresponding to a file mapped
group of regions. The regions to be updated must be grouped, to
allow us to correctly identify extents that have been deallocated
since the map was created.
Tables are built of the file extents, and the extents currently
mapped to dmstats regions: if a region no longer has a matching
file extent, it is deleted, and new regions are created for any
file extents without a matching region.
The FIEMAP call returns extents that are currently in-memory (or
journaled) and awaiting allocation in the file system. These have
the FIEMAP_EXTENT_UNKNOWN | FIEMAP_EXTENT_DELALLOC flag bits set
in the fe_flags field - these extents are skipped until they
have a known disk location.
Since it is possile for the 0th extent of the file to have been
deallocated this must also handle the possible deletion and
re-creation of the group leader: if no other region allocation
is taking place the group identifier will not change.
If the group_id passed to _stats_group_id_present is equal to the
special value DM_STATS_GROUP_NOT_PRESENT there is no need to perform
any further tests: return false immediately.
When showing sizes with 'H|human' units we do use standard rounding.
This however is confusing users from time to time,
when the printed number uses some biger units i.e. GiB and there is just
tiny fraction of space missing.
So here is some real-life example with new 'r' unit.
$lvs
LV VG Attr LSize Pool Origin
lvol0 vg -wi-a----- 1.99g
lvol1 vg -wi-a----- <2.00g
lvol2 vg -wi-a----- <2.01g
Meaning is - lvol1 has 'slightly' less then 2.00g - from sign '<' user
can be aware the LV doesn't have full 2.00GiB in size so he
will be less surpriced allocation of 2G volume will not succeed.
$ vgs
VG #PV #LV #SN Attr VSize VFree
vg 2 2 0 wz--n- <6,00g <2,01g
For uses needing 'old' undecorated human unit simply will continue
to use 'H|h' units.
The new R|r may further change when we would recongnize some
other way how to improve readability.
Call _stats_regions_destroy() from dm_stats_list() if dms->regions
is non-NULL. This avoids leaking any pool allocations and ensures
the handle is in a known state: if an error occurs during the list,
dms->regions will be NULL and the handle will appear empty.
The system is likely in some very inconsisten state.
Do not try to make it even more problematic with trying
to invoke tools like thin_check via callback.
The dm_bit_copy() macro uses the source (bs1) bitset size as the
limit for memcpy:
memcpy((bs1) + 1, (bs2) + 1, ((*(bs1) / DM_BITS_PER_INT) + 1)..)
This is safe if the destination bitset is smaller than the source,
or if the two bitsets are of the same size.
With a destination that is larger (e.g. when resizing a bitmap to
add more capacity), the memcpy will overrun the source bitset and
set garbage bits in the destination.
There are nine uses of the macro currently (8 in libdm/regex, and
1 in daemons/cmirrord): in each case the two bitsets are always of
equal size so the behaviour is unchanged.
Fix the macro to use bs2's size to simplify resizing bitsets and
avoid the need for another copy macro.
If FIEMAP returns a single extent after the first call, no extent
boundary is detected and the first extent is not counted by the
normal mechanism.
In this case, increment nr_extents at the same time the extent is
added to the region table, before returning.
It's useful to be able to specify a minimum number of bits for a
new bitmap parsed from a list, for e.g. to allow for expansing a
group without needing to copy/reallocate the bitmap.
Add a backwards compatible symbol for programs linked against old
versions of the library.
It is sometimes convenient to iterate over the set bits in a dm
bitset in reverse order (from the highest set bit toward zero), or
to quickly find the last set bit.
Add dm_bit_get_last() and dm_bit_get_prev(), mirroring the existing
dm_bit_get_first() and dm_bit_get_next().
dm_bit_get_prev() uses __builtin_clz when available to efficiently
test the bitset in reverse.
Split out the loop that iterates over each batch of FIEMAP
extent data from the function that sets up and calls the ioctl
to reduce nesting and simplify local variable use:
_stats_get_extents_for_file()
-> _stats_map_extents()
The _stats_map_extents() function is responsible for detecting
eof and extent boundaries and adding whole, allocated extents
to the file extent table for region creation.
Check that all region_id values specified in a group bitmap are
actually present: although this should not normally happen when
using the dmstats tool, it is possible as a result of manual
changes (or bugs) for a group descriptor to contain one or more
group_id values that do not exist.
Check for this situation when reading group descriptors, warn
the user the user, and clear these bits in the bitmap when
formatting it for output.
If a region has a a DMS_GROUP tag in aux_data where the first
region_id in the bitmap is not the same as the containing region,
dmstats will segfault:
# '2' is never a valid group bitset list for region_id == 0
# dmsetup message vg_hex/root 0 "@stats_set_aux 0 DMS_GROUP=img:2#"
# dmsetup message vg_hex/root 0 "@stats_list"
0: 45383680+16384 16384 dmstats DMS_GROUP=img:2#
1: 46071808+32768 32768 dmstats -
2: 47382528+16384 16384 dmstats -
# dmstats list
Segmentation fault (core dumped)
The crash will occur in some arbitrary dm_stats_get_* property
method - this happens while processing the 1st region_id in the
bitset, because the region is marked as grouped, but there is
no group bitmap present at dms->groups[2]->regions.
Fix this by detecting a mismatch between the expected region_id
and dm_bit_get_first() for the parsed bitset during
_parse_aux_data_group().
Handle files that contain multiple logical extents in a single
physical extent properly:
- In FIEMAP terms a logical extent is a contiguous range of
sectors in the file's address space.
- One or more physically adjacent logical extents comprise a
physical extent: these are the disk areas that will be mapped
to regions.
- An extent boundary occurs when the start sector of extent
n+1 is not equal to (n.start + n.length).
This requires that we accumulate the length values of extents
returned by FIEMAP until a discontinuity is found (since each
struct fiemap_extent returned by FIEMAP only represents a single
logical extent, which may be contiguous with other logical
extents on-disk).
This avoids creating large numbers of regions for physically
adjacent (logical) extents and fixes the earlier behaviour which
would only map the first logical extent of the physical extent,
leaving gaps in the region table for these files.
When mapping regions to a file descriptor, a temporary table of
extent descriptors is built using the dm_pool object building
interface.
Previously this use borrowed the dms->mem region and counter
table pool (since nothing can interleave with the allocation
while the caller is still in dm_stats_create_regions_from_fd()).
This turns out to be problematic for error recovery. When a
region creation operation fails partway through file mapping,
we need to roll back the set of already created regions and
this requires a listed handle: the dm_stats_list() will then
allocate from the same pool as the extents; we either have
to throw away valid list data, or leak the extent table, to
return the handle in a valid state.
Avoid this problem by creating a new, temporary mem pool in
_stats_create_file_regions() to hold the extent data, and
discarding it on exit from the function.
While cleaning up the table of already created regions during a
failed dm_stats_create_regions_from_fd(), list the handle once,
and call _stats_delete_region() directly. This avoids sending a
@stats_list message for each region deleted, reducing runtime
from 6s to 0.7s when cleaning up ~250 out of ~10000 regions:
# time dmstats create --filemap b.img
device-mapper: message ioctl on (253:0) failed: Cannot allocate memory
Failed to create region 246 of 309 at 9388032.
Could not create regions from file /root/b.img
<< pauses here >>
Command failed
real 0m6.267s
user 0m3.770s
sys 0m2.487s
# time dmstats create --filemap b.img
device-mapper: message ioctl on (253:0) failed: Cannot allocate memory
Failed to create region 246 of 309 at 9388032.
Could not create regions from file /root/b.img
Command failed
real 0m0.716s
user 0m0.034s
sys 0m0.581s
Testing the error path requires region creation to start to
fail part way through the operation (in order to have regions
to clean up): the simplest way is to ensure the system is
close to the kernel limit of 1/4 RAM or 1/2 vmalloc space
consumed by dmstats data.
Split dm_stats_delete_region() so that internal callers can manage
the handle state themselves.
dm_stats_delete_region() now just handles checking the state of the
handle, reporting validation errors, and calling dm_stats_list() if
necessary, before calling _stats_delete_region().
The new _stats_delete_region() function performs the actual group
member removal and region deletion, and requires a fully listed
handle to operate.
Callers that repeatedly delete regions can use a single listed
handle for many operations on the same device, avoiding one
message ioctl per region deleted: since @stats_list with many
regions is expensive, this yields large runtime improvements.
If we fail to create a region during dm_stats_create_regions_from_fd(),
we must remove all regions that were created to do this to date. This
needs to loop over the table of region_id values that were populated
by _stats_create_file_regions() before the error.
The code for this failure case in the out_remove branch incorrectly
uses the table index as the region_id:
for (--i; i != DM_STATS_REGION_NOT_PRESENT; i--) {
if (!dm_stats_delete_region(dms, i))
log_error("Could not delete region " FMTu64 ".", i);
}
This causes the cleanup code to delete a completely unrelated set
of regions (since the index here will always be nr_regions..0).
Fix it to pass the actual region_id stored in regions[i] instead.
Fix a silly bug in dm_stats_delete_region() that hugely inflates
runtimes when deleting a large number of regions.
For ~50,000 regions this change reduces the runtime from 98s to
6s on my test systems (a ~93% reduction).
The bug exists because dm_stats_delete_region() applies a truth
test to the return value of dm_stats_get_nr_areas(); this is
never correct usage - it will walk the entire region table and
calculate area counts for each region (which is roughly O(n^2)
in the number of regions, as dm_stats_delete_region() is being
called inside a region walk).
Although the individual area calculation is not that costly,
uselessly running anything 2,500,000,000 times over gets a bit
slow.
A much cheaper test (which is always true if the areas check is
true) is to just test dm_stats_get_nr_regions() or dms->regions;
if either is true it implies at least one area exists.
Old:
Performance counter stats for 'dmstats delete --allregions --alldevices':
98117.791458 task-clock (msec) # 1.000 CPUs utilized
127 context-switches # 0.001 K/sec
3 cpu-migrations # 0.000 K/sec
6,631 page-faults # 0.068 K/sec
307,711,724,562 cycles # 3.136 GHz
544,762,959,577 instructions # 1.77 insn per cycle
84,287,824,115 branches # 859.047 M/sec
2,538,875 branch-misses # 0.00% of all branches
98.119578733 seconds time elapsed
New:
Performance counter stats for 'dmstats delete --allregions --alldevices':
6427.251074 task-clock (msec) # 1.000 CPUs utilized
6 context-switches # 0.001 K/sec
0 cpu-migrations # 0.000 K/sec
6,634 page-faults # 0.001 M/sec
21,613,018,724 cycles # 3.363 GHz
3,794,755,445 instructions # 0.18 insn per cycle
852,974,026 branches # 132.712 M/sec
808,625 branch-misses # 0.09% of all branches
6.428953647 seconds time elapsed
There are two possible errors in _dm_stats_populate_region():
* No region struct in dms->regions[region_id]
* Failure to parse data from @stats_print
These have very different causes: the first occurs where a client
program is populating one region at a time (region_id is a single
region identifier), and has not previously called dm_stats_list()
to dimension the region tables; this is an API usage error.
The second occurs when either we read unparseable data from the
kernel (kernel bug), or where various resource allocations fail.
Separate these two cases out and log separate messages for each
(allocation failures in the path already have their own distinct
message), since the "failed to parse.." message in the un-listed
handle case is confusing and misleading.
Translate log_info() into log_very_verbose() which is macro
supposed to be used by our code.
log_info() is internal macro with eventually some 'symbolic' meaning
in syslogging daemons.
Instead of compiling 2 log call for 2 different logging functions,
and runtime decide which version to use - use only 'newer' function
and when user sets his own OLD dm_log logging translate it runtime
for old arg list set.
The positive part is - we get shorter generated library,
on the negative part this translation means, we always have evaluate
all args and print the message into local on stack buffer, before
we can pass this buffer to the users' logging function with proper
expected parameters (and such function may later decide to discard
logging based on message level so whole printing was unnecessary).
Introduce macros:
log_level(), log_stderr(), log_once(), log_bypass_report()
For easier and more consisten way how to 'decoder' bits
of info from passed 'level'.
This patch fixes potential problem when 'level' of message
might not have always masked right bits.
The dm_stats_delete_region() call removes a region from the bound
device, and, if the region is grouped, from the group leader
group descriptor stored in aux_data.
To do this requires a listed handle: previous versions of the
library do not since no dependencies exist between regions without
grouping.
This leads to strange behaviour when a command built against an old
version of the library is used with one supporting groups. Deleting
a region with dmstats succeeds, but logs errors:
# dmstats list
Name RgID RgSta RgSiz #Areas ArSize ProgID
vg_hex-root 0 0 1.00g 1 1.00g dmstats
vg_hex-root 1 1.00g 1.00g 1 1.00g dmstats
vg_hex-root 2 2.00g 1.00g 1 1.00g dmstats
# dmstats delete --regionid 2 vg_hex/root
Region ID 2 does not exist
Could not delete statistics region.
Command failed
# dmstats list
Name RgID RgSta RgSiz #Areas ArSize ProgID
vg_hex-root 0 0 1.00g 1 1.00g dmstats
vg_hex-root 1 1.00g 1.00g 1 1.00g dmstats
This happens because the call to dm_stats_delete_region() is inside
a dm_stats_walk_*() iterator: upon entry to the call, the iterator
is at its end conditions and about to terminate. Due to the call to
dm_stats_list() inside the function, it returns with an iterator at
the beginning of a walk and performs a further iteration before
exiting. This final loop makes a further attempt to delete the
(already deleted) region, leading to the confusing error messages.
The current dmsetup.c handles DR_STATS and DR_STATS_META reports
separately in _display_info_cols(), meaning that the stats walk
functions are never called for these report types.
Versions before v2.02.159 have a loop using dm_stats_walk_do() and
dm_stats_walk_while(), that executes once for non-stats reports,
and once per region, or area, for DR_STATS/DR_STATS_META reports.
This older behaviour relies on the documented behaviour that the
walk functions will accept a NULL pointer as the struct dm_stats*
argument.
This was broken by commit f1f2df7b: the NULL test on dms and
dms->regions were incorrectly moved from the dm_stats_walk_end()
wrapper to the internal '_stats_walk_end()' helper.
Since the pointer is dereferenced in between these points, using
an older dmsetup with current libdm results in a segfault when
running a non-stats report:
# dmsetup info -c vg00/lvol0
Segmentation fault (core dumped)
Restore the NULL checks to the wrapper function as intended.
The dm_report_group_output_and_pop_all calls dm_report_output and
dm_report_group_pop for all the items that are currently in report
group. This is just a shortcut that makes it easier to output and
pop group's content so the group handle can be reused again without
a need to initialize and configure it again.
The functionality of dm_report_group_output_and_pop_all is the
same as dm_report_destroy but without destroying the report group
handle.
This patch moves printing of starting '{' character for JSON output up
untili it's known there's any further output following - either the
content or ending '}' character.
Also, remove unnecessary switch for different report group types and
calling individual functions to handle dm_report_group_create as that
code is shared for all existing types at the moment.
Calling dm_report_destroy_rows makes it possible to destroy any report
content we have but at the same time it doesn't destroy the report
handle itself, thus it's possible to reuse that handle again for new
report content.
Functionally, this is the same as calling dm_report_output with the
report handle but omitting the output iself. This functionality may
be useful if we, for whatever reason, need to discard the report
content and start a fresh new one but with the same report configuration
and initialization and thus we can just reuse the existing handle.
Support aggregate group and region histograms by allocating a new
histogram from the pool and populating it with a sum of the histogram
data for the areas contained in the region or group.
To avoid repeatedly summing the same histogram data, cache the pointer
in the group and regions structs for subsequent access. The aggregate
histograms are allocated from the same pool as the area histograms in
the corresponding handle and will be discarded at each list or populate
operation.
Add a call to create dmstats regions that correspond to the extents
present in a file descriptor open on a file in a local file system.
The file must reside on a file system type that correctly supports
physical extent location data in the FIEMAP ioctl.
Regions are optionally placed into a group with a user-defined alias.
File systems that do not support physical offsets in FIEMAP (btrfs
currently) are detected via fstatfs() - although attempting to map
a --filemap group on btrfs will fail anyway with the generic error
"Not on a device-mapper device" this is confusing; the file system
mount is on a device-mapper device, but btrfs' volume layer masks
this in the returned st_dev field since the returned logical file
extents may span multiple physical devices.
The function _stats_remove_region_id_from_group() incorecctly set
the group_id to DM_STATS_GROUP_NOT_PRESENT _before_ the call to
_stats_group_destroy(). This will cause the destroy function to
return immediately without doing anything:
339 static void _stats_group_destroy(struct dm_stats_group *group)
340 {
341 if (!_stats_group_present(group))
342 return;
Invalidating the ID in _stats_region_region_id_from_group() is
redundant anyway; it is rightly done as the last operation in
_stats_group_destroy (and it is not possible for anything to see
the old value between the two calls).
Remove the change to group_id to ensure that the alias and bitset
resources are correctly freed.
The call to dm_stats_walk_start() before the do statement makes
dm_stats_walk_do() behave inconsistently depending on context;
wrap them in an additional do { } while (0) so that the macro
always expands to a valid statement.
If after extracting stats arguments and group tags nothing remains
of aux_data but '-' set the region->aux_data field to the empty
string to match behaviour for non-grouped regions.
Although not harmful do not allow a group containing regions with
histograms since it is not currently possible to present histogram
data aggregated for the group.
Although a non-zero value for the number of ticks spent doing IO
should imply a non-zero number of IOs in the interval test for
this explicitly to avoid a divide-by-zero in the event of bad
counter data.
It's possible for interval_ns to be zero if the interval is not
set or the clock is misconfigured. Test for this before using the
value as the divisor in the utilisation calculation.
Walk flags are ULL constants; cast the result to a uint64_t before
logging with a FMTx64 format specifier to avoid a compiler warning:
warning: format ‘%lx’ expects argument of type ‘long unsigned int’,
but argument 5 has type ‘long long unsigned int’
Make it clear in libdevmapper.h, and in function argument names, that
libdm-stats uses the aux_data field internally and that any values set
for user_data are appended to the library values before being stored
with a region, and similarly, that internal data fields will be stripped
prior to returning any previously stored user_data.
Add support do dm_stats_walk*() to walk over the set of
available groups using the cursor embedded in the dm_stats
handle, and to obtain the type of the object at the current
stats cursor location. A set of flags is introduced to
control which objects are visited:
DM_STATS_WALK_AREA
DM_STATS_WALK_REGION
DM_STATS_WALK_GROUP
DM_STATS_WALK_ALL
A final flag suppresses visits to regions that contain only a
single area - since the aggregate of such a region is idential
to the area it contains this allows these duplicates to be
filtered out:
DM_STATS_WALK_SKIP_SINGLE_AREA
If flags are not initialised before beginning a walk the default
set matches the behaviour of previous versions of the library.
Also accept group identifiers as immediate arguments to the
counter, metric, and property functions by adding control
flags to the region and area identifiers passed in.
Region and area properties are mapped to their equivalents for
the group (for example: group size is reported as the sum of
all regions contained in the group). Counter and metric values
are aggregated for the region or group.
Introduce constants for the buffer sizes that libdm-stats uses:
one for messages sent to the kernel, one for rows of response data
returned, and a pair for the "start+len" range and histogram bounds
strings.
Add a grouping facility to the libdm-stats library that allows the
user to bind several regions together as a group. Groups may be
used to aggregate data from several regions for reporting, or to
select and sort among large sets of regions.
A textual descriptor ("group tag") is associated with each group
and is stored in the first group member's aux_data field. The
tag contains the group member list and an optional alias for the
group, allowing the user to assign meaningful names to groups of
regions.
These descriptors are parsed in @stats_list message responses and
populate the resulting region and area tables with the group
structure.
Groups with overlapping regions are permitted but since this will
result in some events being counted more than once a warning is
printed in this case.
Nested and overlapping groups are not currently supported and
attempting to create these configurations results in error.
Add a new enum based interface for accessing counter and metric
values that uses a single function for each:
uint64_t dm_stats_get_counter(const struct dm_stats *dms,
dm_stats_counter_t counter
uint64_t region_id, uint64_t area_id);
int dm_stats_get_metric(const struct dm_stats *dms, int metric,
uint64_t region_id, uint64_t area_id,
double *value);
This simplifies the implementation of value aggregation for
groups of regions. The named function interface now calls the
enum interface internally so that all new functionality is
available regardless of the method used to retrieve values.
Cache the device-mapper name of a bound device in the dm_stats
handle.
This will be used by stats groups to report a device name or
user defined alias for groups.
The device-mapper name, device numbers and uuid stored in the
dm_stats handle are used only to bind the handle to a specific
device in order to issue ioctls.
Rename them to "bind_*" to reflect this usage in preparation
for caching the device-mapper name of the bound device in the
dm_stats handle.
This will be used to allow optional aliases to be set for
dmstats groups.
Add a function to parse a list of integer values and ranges into
a dm_bitset representation. Individual values signify that that bit
is set in the resulting mask and ranges are given as a pair of
start and end values, M-N, such that M and N are the first and
last members of the range (inclusive).
The implementation is based on the kernel's __bitmap_parselist()
that is used for cpumasks and other set configuration passed in
string form from user space.
There are detailed messages inside _create_dir_recursive that
dm_create_dir calls (except EROFS which where the message is not
generated, like anywhere else in the code).
This fixes commit 0ba5f4b8e9 which moved
field recalculation (field width and sort position) from
dm_report_object to dm_report_output but it didn't handle the case when
dm_report_column_headings was used separately to report headings (before
dm_report_outpout call) and hence we ended up with intial widths for
fields in the headings.
If we're using dm_report_column_headings, we need to recalculate
fields if we haven't done so yet, the same way as we do in
dm_report_output.
Uninitialized variables (UNINIT) /safe/guest2/covscan/LVM2.2.02.158/tools/toollib.c: 3520 in _process_pvs_in_vgs()
Uninitialized variables (UNINIT) Using uninitialized value "do_report_ret_code".
Null pointer dereferences (REVERSE_INULL) /safe/guest2/covscan/LVM2.2.02.158/libdm/libdm-report.c: 4745 in dm_report_output()
Null pointer dereferences (REVERSE_INULL) Null-checking "rh" suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
Incorrect expression (MISSING_COMMA) /safe/guest2/covscan/LVM2.2.02.158/lib/log/log.c: 280 in _get_log_level_name()
Incorrect expression (MISSING_COMMA) In the initialization of "log_level_names", a suspicious concatenated string ""noticeinfo"" is produced.
Null pointer dereferences (FORWARD_NULL) /safe/guest2/covscan/LVM2.2.02.158/tools/reporter.c: 816 in_get_report_options()
Null pointer dereferences (FORWARD_NULL) Comparing "mem" to null implies that "mem" might be null.
This fixes commit f50d4011cd which
introduced a problem when using older lvm2 code with newer libdm.
In this case, the old LVM didn't recognize new _LOG_BYPASS_REPORT flag
that libdm-report code used. This ended up with no output at all
from libdm where log_print_bypass_report was called because the
_LOG_BYPASS_REPORT was not masked properly in lvm2's print_log fn
which was called as callback function for logging.
With this patch, the lvm2 registers separate print_log_libdm logging
function for libdm instead. The print_log_libdm is exactly the same
as print_log (used throughout lvm2 code) but it checks whether we're
printing common line on output where "common" means not going to stderr,
not a warning and not an error and if we are, it adds the
_LOG_BYPASS_REPORT flag so the log_print goes directly to output, not
to any log report.
So this achieves the same goal as in f50d4011cd,
just doing it in a way that newer libdm is still compatible with older
lvm2 code (libdm-report is the only code using log_print).
Looking at the opposite mixture - older libdm with newer lvm2 code,
that won't be compilable because the new log report functionality
that is in lvm2 also requires new dm_report_group_* libdm functions
so we don't need to care here.
The DM_REPORT_OUTPUT_MULTIPLE_TIMES instructs reporting code to
keep rows even after dm_report_output call - the rows are not
destroyed in this case which makes it possible to call dm_report_output
multiple times.
This allows for moving parts of the code from dm_report_object to
dm_report_output which is important for subsequent patches that allow
for repeated dm_report_output, not destroying rows on each
dm_report_output call.
log_print is used during cmd line processing to log the result of the
operation (e.g. "Volume group vg successfully changed" and similar).
We don't want output from log_print to be interleaved with current
reports from group where log is reported as well. Also, the information
printed by log_print belongs to the log report too, so it should be
rerouted to log report if it's set.
Since the code in libdm-report which is responsible for doing the report
output uses log_print too, we need to use a different kind of log_print
which bypasses any log report currently used for logging (...simply,
we can't call log_print to output the log report itself which in turn
would again reroute to report - the report would never get on output
this way).
This patch introduces DM_REPORT_GROUP_JSON report group type. When using
this group type and when pushing a report to such a group, these flags
are automatically unset:
DM_REPORT_OUTPUT_ALIGNED
DM_REPORT_OUTPUT_HEADINGS
DM_REPORT_OUTPUT_COLUMNS_AS_ROWS
...and this flag is set:
DM_REPORT_OUTPUT_BUFFERED
The whole group is encapsulated in { } for the outermost JSON object
and then each report is reported on output as array of objects where
each object is the row from report:
{
"report_name1": [
{field1="value", field2="value",...},
{field1="value", field2="value",...}
...
],
"report_name2": [
{field1="value", field2="value",...},
{field1="value", field2="value",...}
...
]
...
}
This patch introduces DM_REPORT_GROUP_BASIC report group type. This
type has exactly the classical output format as we know from before
introduction of report groups. However, in addition to that, it allows
to put several reports into a group - this is the very basic grouping
scheme that doesn't change the output format itself:
Report: report1_name
Header1 Header2 ...
value value ...
value value ...
... ... ...
Report: report2_name
Header1 Header2 ...
value value ...
value value ...
... ... ...
There's no change in output for this report group type - with this type,
we only make sure there's always only one report in a group at a time,
not more.
This patch introduces DM report group (represented by dm_report_group
structure) that is used to group several reports to make a whole. As a
whole, all the reports in the group follow the same settings and/or
formatting used on output and it controls that the output is properly
ordered (e.g. the output from different reports is not interleaved
which would break readability and/or syntax of target output format
used for the whole group).
To support this feature, there are 4 new functions:
- dm_report_group_create
- dm_report_group_push
- dm_report_group_pop
- dm_report_group_destroy
From the naming used (dm_report_group_push/pop), it's clear the reports
are pushed onto a stack. The rule then is that only the report on top
of the stack can be reported (that means calling dm_report_output).
This way we make sure that the output is not interleaved and provides
determinism and control over the output.
Different formats may allow or disallow some of the existing report
flags controlling output itself (DM_REPORT_OUTPUT_*) to be set or not so
once the report is pushed to a group, the grouping code makes sure that
all the reports have compatible flags set and then these flags are
restored once each report is popped from the report group stack.
We also allow to push/pop non-report item in which case such an item
creates a structure (e.g. to put several reports together with any
opening and/or closing lines needed on output which pose as extra
formatting structure besides formatting the reports).
The dm_report_group_push function accepts an argument to pass any
format-specific data needed (e.g. handle, name, structures passed
along while working with reports...).
We can call dm_report_output directly anytime we need (with the only
restriction that we can call dm_report_output only for the report that
is currently on top of the group's stack). Or we don't need to call
dm_report_output explicitly in which case all the reports in a stack are
reported on output automatically once we call dm_report_group_destroy.
This reverts commit 8fd886f735.
This was a deliberate omission because logging token-by-token metadata
parsing greatly increases the amount of logging for hardly any benefit.
In general, only LVM config file settings need to be logged, and in
places where it's considered important to log particular elements of
metadata that should be done using specific log_* lines.
This area can be revisited.
Check that @stats_list and @stats_print returned data in the
_stats_parse_list() and _stats_parse_region() functions before
attempting to operate on region and area values.
This avoids a coverity warning since fgets() could potentially
return no data from the memory buffer returned by the ioctl.
In both cases the ioctl would return an error, preventing these
functions from running, however it is cleaner to test for the
condition explicitly and fail in those cases.
When dm_tree_find_node_by_uuid() fails to find passed uuid,
report in lof_debug the complete original uuid,
not the one stripped of LVM- prefix.
TODO: inspect manipulation with LVM- prefix here.
Fix parsing of 'Fail' status (using capital letter) for thin-pool.
Add also parsing of 'Error' state for thin-pool.
Add needs_check test for thin-pool.
Detect Fail state for thin.
Fixing regression caused by 197b5e6dc7.
So the 'TODO' part now finally know the answer - there is 'sparc64'
architecture which imposes limitation to read 64b words only through
64b aligned address.
Since we never could know how is the user going to use the returned
pointer and the userusually expects it's aligned on the highest CPU
required alignement, preserve it also for char*.
Fixes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=809685
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Wrong thin-pool feature flag ordering in dm table: It will lead to
unnecessary table reload.
Fix it by placeing feature flags in order they are returned from the
kernel so current 'table line diff' code will not see a difference.
When preloading thin-pool device node for already
existing/running thin-pool do not resume such thin-pool.
This allows to properly schedule commit point for metadata,
when thin-pool data or metadata volume is resized.
Extra space between 'cache' target and metadata device caused
string comparation being not equal and thus always causing
table reload even when uneeded.
In lookup, return a count of entries with the
same key rather than the value from a second
entry with the same key.
Using some slightly different names.
If the data len is passed into the hash table
and saved there, then the hash table internals
do not need to assume that the data value is
a string at any point.
New hash table functions are added that allow for
multiple entries with the same key. Use of the
vgname_to_vgid hash table is converted to these
new functions since there are multiple entries
in vgname_to_vgid that have the same key (vgname).
When multiple VGs with the same name exist, commands
that reference only a VG name will fail saying the
VG could not be found (that error message could be
improved.) Any command that works with the select
option can access one of the VGs with -S vg_uuid=X.
vgrename is a special case that allows the first VG
name arg to be replaced by a uuid, which also works.
(The existing hash table implementation is not well
suited for handling this case, but it works ok with
the new extensions. Changing lvmetad to use its own
custom hash tables may be preferable at some point.)
Add more functionality to size_changed function.
While 'existing' API only detected 0 for
unchanged, and !0 for changed,
new improved API will also detected if the
size has only went bigger - or there was
size reduction.
Function work for the whole dm-tree - so
no change is size is always 0.
only size extension 1.
and if some size reduction is there - returns -1.
This result can be used for better evaluation
whether we need to flush before suspend.
The new report/compact_output_cols setting has exactly the same effect
as report/compact_output setting. The difference is that with the new
setting it's possible to define which cols should be compacted exactly
in contrast to all cols in case of report/compact_output.
In case both compact_output and compact_output_cols is enabled/set,
the compact_output prevails.
For example:
$ lvmconfig --type full report/compact_output report/compact_output_cols
compact_output=0
compact_output_cols=""
$ lvs vg
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
lvol0 vg -wi-a----- 4.00m
---
$ lvmconfig --type full report/compact_output report/compact_output_cols
compact_output=0
compact_output_cols="data_percent,metadata_percent,pool_lv,move_pv,origin"
$ lvs vg
LV VG Attr LSize Log Cpy%Sync Convert
lvol0 vg -wi-a----- 4.00m
---
$ lvmconfig --type full report/compact_output report/compact_output_cols
compact_output=1
compact_output_cols="data_percent,metadata_percent,pool_lv,move_pv,origin"
$ lvs vg
LV VG Attr LSize
lvol0 vg -wi-a----- 4.00m
dm_report_compact_given_fields is the same as dm_report_compact_fields,
but it processes only given fields, not all the fields in the report
like dm_report_compact_field does.
Also make error messages more consistent:
Before this patch:
(/run/lock exists and is not a directory)
$ pvs
/run/lock/lvm: mkdir failed: Not a directory
File-based locking initialisation failed.
(/run/lock/lvm exists and is not a directory)
$ pvs
Directory "/run/lock/lvm" not found
File-based locking initialisation failed.
With this patch applied:
(/run/lock exists and is not a directory)
$ pvs
Existing path /run/lock is not a directory.
Failed to create directory /run/lock/lvm.
File-based locking initialisation failed
(/run/lock/lvm exists and is not a directory)
$ pvs
Existing path /run/lock/lvm is not a directory.
Failed to create directory /run/lock/lvm.
File-based locking initialisation failed.
When using udev, the /dev/mapper entries are symlinks - fix the code
to count with this.
This patch also fixes the dmsetup mknodes and vgmknodes to properly
repair /dev/mapper content if it sees dangling symlink in /dev/mapper.
$ lvs -o name,tags vg
LV LV Tags
lvol0
lvol1 mytag
Before this patch:
$ lvs -o name,tags vg -S 'tags=""'
Failed to parse string list value for selection field lv_tags.
Selection syntax error at 'tags=""'.
Use 'help' for selection to get more help.
(and the same for -S 'tags={}' and -S 'tags=[]')
With this patch applied:
$ lvs -o name,tags vg -S 'tags=""'
LV LV Tags
lvol0
(and the same for -S 'tags={}' and -S 'tags=[]')
Avoid validation of free space in pool, when no messages are passed.
Patch a3c7e326c3 add new check for
pool overload - but this check should not be made if there are
no messages and transaction_id is still within 'bounds' (bigger by 1).
Split up _build_histogram_arg() into separate functions to allocate
and fill the histogram arg string and remove nested local variable
declarations from the parent function.
Coverity flags a user-after-free in _stats_histograms_destroy():
>>> Calling "dm_pool_free" frees pointer "mem->chunk" which has
>>> already been freed.
This should not be possible since the histograms are destroyed in
reverse order of allocation:
203 for (n = _nr_areas_region(region) - 1; n; n--)
204 if (region->counters[n].histogram)
205 dm_pool_free(mem, region->counters[n].histogram);
It appears that Coverity is unaware that pool->chunk is updated
during the call to dm_pool_free() and valgrind flags no errors in
this function when called with multiple allocated histograms.
Since there is no actual need to free the histograms individually
in this way simplify the code and just free the first allocated
object (which will also free all later allocated histograms in a
single call).
The histogram changes adds a new error path to dm_stats_create().
Make sure that the dm_stats handle is properly destroyed if we fail
to create the histogram pool and check for failures setting the
program_id.
Since we are growing an object in the histogram pool the return
value of dm_pool_grow_object() must be checked and error paths need
to abandon the object before returning.
Older versions of gcc aren't able to track the assignments of
local variables as well as the latest versions leading to spurious
warnings like:
libdm-stats.c:2183: warning: "len" may be used uninitialized in this
function
libdm-stats.c:2177: warning: "minwidth" may be used uninitialized in
this function
Both of these variables are in fact assigned in all possible paths
through the function and later compilers do not produce these
warnings.
There's no reason to not initialize these variables though and
it makes the function slightly easier to follow.
Also fix one use of 'unsigned' for a nr_bins value.
librt doesn't have a pkgconfig file so use Libs.private: -lrt instead
to declare the dependency directly.
The same applies for -lm which is also used and which hasn't been
defined in the devmapper.pc file yet.
Add support for creating, parsing, and reporting dm-stats latency
histograms on kernels that support precise_timestamps.
Histograms are specified as a series of time values that give the
boundaries of the bins into which I/O counts accumulate (with
implicit lower and upper bounds on the first and last bins).
A new type, struct dm_histogram, is introduced to represent
histogram values and bin boundaries.
The boundary values may be given as either a string of values (with
optional unit suffixes) or as a zero terminated array of uint64_t
values expressing boundary times in nanoseconds.
A new bounds argument is added to dm_stats_create_region() which
accepts a pointer to a struct dm_histogram initialised with bounds
values.
Histogram data associated with a region is parsed during a call to
dm_stats_populate() and used to build a table of histogram values
that are pointed to from the containing area's counter set. The
histogram for a specified area may then be obtained and interogated
for values and properties.
This relies on kernel support to provide the boundary values in
a @stats_list response: this will be present in 4.3 and 4.2-stable. A
check for a minimum driver version of 4.33.0 is implemented to ensure
that this is present (4.32.0 has the necessary precise_timestamps and
histogram features but is unable to report these via @stats_list).
Access methods are provided to retrieve histogram values and bounds
as well as simple string representations of the counts and bin
boundaries. Methods are also available to return the total count
for a histogram and the relative value (as a dm_percent_t) of a
specified bin.
For repeating reports field widths should be re-calculated for
each report interval. Not doing so will cause a single row with
wide field data to cause all subsequent rows to share the width:
Name RgID ArID R/s W/s Histogram Bounds
vg_hex-lv_home 0 0 4522.00 834.00 0s: 991, 2ms: 152, 4ms: 161, 6ms: 4052 0s, 2ms, 4ms, 6ms
vg_hex-lv_swap 0 0 0.00 0.00 0s: 0, 2ms: 0, 4ms: 0, 6ms: 0 0s, 2ms, 4ms, 6ms
vg_hex-lv_root 0 0 1754.00 683.00 0s: 369, 2ms: 65, 4ms: 90, 6ms: 1913 0s, 2ms, 4ms, 6ms
luks-79733921-3f68-4c92-9eb7-d0aca4c6ba3e 0 0 4522.00 868.00 0s: 985, 2ms: 152, 4ms: 161, 6ms: 4092 0s, 2ms, 4ms, 6ms
vg_hex-lv_images 0 0 0.00 0.00 0s: 0, 2ms: 0, 4ms: 0, 6ms: 0 0s, 2ms, 4ms, 6ms
Name RgID ArID R/s W/s Histogram Bounds
vg_hex-lv_home 0 0 0.00 0.00 0s: 0, 2ms: 0, 4ms: 0, 6ms: 0 0s, 2ms, 4ms, 6ms
vg_hex-lv_swap 0 0 0.00 0.00 0s: 0, 2ms: 0, 4ms: 0, 6ms: 0 0s, 2ms, 4ms, 6ms
vg_hex-lv_root 0 0 0.00 2.00 0s: 1, 2ms: 0, 4ms: 0, 6ms: 1 0s, 2ms, 4ms, 6ms
luks-79733921-3f68-4c92-9eb7-d0aca4c6ba3e 0 0 0.00 0.00 0s: 0, 2ms: 0, 4ms: 0, 6ms: 0 0s, 2ms, 4ms, 6ms
vg_hex-lv_images 0 0 0.00 0.00 0s: 0, 2ms: 0, 4ms: 0, 6ms: 0 0s, 2ms, 4ms, 6ms
^^^^^^^^^^^^^^^^^
This is especially significant for the current histogram fields:
depending on the time since the last clear operation the first
report iteration may contain very large values leading to a very
large minimum field width. Without resetting field widths this
large minimum field width value is used for all subsequent rows.
dm_stats_create_region is now assigned to DM_1_02_106 by default:
the DM_1_02_104 .exported_symbols file entry was moved into
libdm-stats.c as:
DM_EXPORT_SYMBOL(dm_stats_create_region, 1_02_104)
so delete it from .exported_symbols.DM_1_02_104.
Add support for the kernel precise_timestamps feature. This allows
regions to be created using counters with nanosecond precision.
A new dm_stats method, dm_stats_set_precise_timestamps() causes all
future regions created with this handle to attempt to enable precise
counters.
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.
Add a function to test whether the kernel precise_timestamps
feature is available in the current device-mapper driver version.
Presence of precise_timestamps also implies the availability of
latency histograms.
We already use -lm functions in a couple of places (these are
satisfied by gcc built-ins for most builds): add a configure.in
check and explicitly link to -lm.
Several interfaced in libdm-stats return a uint64_t when it is
only used to signal success/failure: change all these uses to
return a simple int instead.
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.
Add a method to retrieve the offset of an area within the
containing region (rather than the offset within the containing
device returned by dm_stats_get_area_start()).
Although users of the library can calculate this themselves it is
better to provide this through a method call to avoid users making
assumptions about the structure of regions and areas.
The dm_stats_get_area_start (and its '_current_' variant) methods
are expected to return the start sector of the area in the
containing device.
Make sure the call adds region->start to the returned value.
Do not include bits/time.h as it is an internal libc header file.
A comment at the top of the glibc specific bits/time.h says:
"Never include this file directly; use <time.h> instead."
This fixes the following build error with musl libc:
libdm-timestamp.c:37:23: fatal error: bits/time.h: No such file or directory
---
Compile tested with Alpine Linx (musl libc) and ubuntu 15.04
libdm/libdm-timestamp.c | 1 -
1 file changed, 1 deletion(-)
Introduce enums and global variables to record cleanly which command we
are processing and eliminate the historically inconsistent use of the
shifted argv[0] and fix assorted bugs discovered along the way.
Add dm_report_is_empty() to indicate there is no data awaiting output
and use this to suppress dmsetup report headings when no data is output
so we don't get a stray line saying 'Help' at the end of reporting help.
Define a report type (as the interface requires) so -o all selects
the right fields in splitname. (A fix for stats list will follow.)
Exit immediately if no device is supplied to dmsetup wipe_table instead
of hitting errors later and failing.
Adjust the command name printed in usage/help output to match command
invoked (most of the time).
Since libdm-stats only uses fmemopen'd FILE objects the only way
that a close can fail is corruption of the memory containing the
FILE: check for this case and emit a backtrace if it occurs.
libdm/libdm-stats.c: 338 in _stats_parse_list()
libdm/libdm-stats.c: 341 in _stats_parse_list()
libdm/libdm-stats.c: 481 in _stats_parse_region()
libdm/libdm-stats.c: 487 in _stats_parse_region()
libdm/libdm-stats.c: 487 in _stats_parse_region()
- Calling "fclose" without checking return value
Remove an unneccessary conditional operator and simplify the logic
in _nr_areas:
libdm/libdm-stats.c: 501 in _nr_areas() - Control flow issues (DEADCODE)
Make sure the newly created handle is freed if we are unable to
also create the pool for it.
tools/dmsetup.c: 4255 in _stats_list() - Variable "dms" going out of scope leaks the storage it points to.
Make sure comm is closed in the error path of _program_id_from_proc().
libdm/libdm-stats.c: 98 in dm_stats_create() - Variable "comm" going out of scope leaks the storage it points to.
Add the libdm-stats module to libdm: this implements a simple interface
for creating, managing and interrogating I/O statistics regions and
areas on device-mapper devices.
The library interface is documented in libdevmapper.h and provides a
'dm_stats' handle that is used to perform statistics operations and
obtain data.
Public methods are provided to create and destroy handles and to list,
create, and destroy statistics regions as well as to obtain and parse
counter data and calculate rate-based metrics.
This commit also adds a 'dmsetup stats' (aka 'dmstats') command with
'clear', 'create', 'delete', 'list', 'print', and 'report' sub-commands.
See the library documentation and the dmstats.8 manual page for detailed
API and command descriptions.
Don't do interval management and external timekeeping for stats in
dm_report: let applications handle this on their own.
Since this has not been included in a release remove it from the
library entirely and handle report timing directly inside dmsetup.
Add a function to print column headings regardless of whether they
have already been output. This will be used by dmstats to issue
periodic reminders of the column headings.
This patch removes a check for RH_HEADINGS_PRINTED from
_report_headings that prevents headings being displayed if the flag
is already set; this check is redundant since the only existing
caller (_output_as_columns()) already tests the flag before
calling the function.
Not releasing objects back to the pool is fine for short-lived
pools since the memory will be freed when dm_pool_destroy() is
called.
Any pool that may be long-lived needs to be more careful to free
objects back to the pool to avoid leaking memory that will not be
reclaimed until the pool is destroyed at process exit time.
The report pool currently leaks each headings line and some row
data.
Although dm_report_output() tries to free the first allocated row
this may end up freeing a later row due to sorting of the row list
while reporting. Store a pointer to the first allocated row from
_do_report_obect() instead and free this at the end of
_output_as_columns(), _output_as_rows(), and dm_report_clear().
Also make sure to call dm_pool_free() for the headings line built
in _report_headings().
When dmstats is introduced it will maintain dm_report objects for
the whole lifetime of the process: without these changes a stats
report could leak around 600k in 10m (exact rate depends on field
selection and data values):
top - 12:11:32 up 4 days, 3:16, 15 users, load average: 0.01, 0.12, 0.14
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
6473 root 20 0 130196 3124 2792 S 0.0 0.0 0:00.00 dmstats
top - 12:22:04 up 4 days, 3:26, 15 users, load average: 0.06, 0.11, 0.13
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
6498 root 20 0 130836 3712 2752 S 0.0 0.0 0:00.60 dmstats
With this patch no increase in RSS is seen:
top - 13:54:58 up 4 days, 4:59, 15 users, load average: 0.12, 0.14, 0.14
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
13962 root 20 0 130196 2996 2688 S 0.0 0.0 0:00.00 dmstats
top - 14:04:31 up 4 days, 5:09, 15 users, load average: 1.02, 0.67, 0.36
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
13962 root 20 0 130196 2996 2688 S 0.3 0.0 0:00.32 dmstats
This also affects report output for repeating reports in the
DM_REPORT_OUTPUT_COLUMNS_AS_ROWS case; row state is not fully cleared for
the next iteration leading to progressive growth of the heading width:
vg_hex-lv_home:vg_hex-lv_swap:vg_hex-lv_root:luks-79733921-3f68-4c92-9eb7-d0aca4c6ba3e:vg_hex-lv_images
253:253:253:253:253
2:0:1:4:3
L--w:L--w:L--w:L--w:L--w
1:2:1:1:1
3:1:1:1:2
0:0:0:0:0
LVM-9t8ITqLZa6AuuyVoz5Olp1KwF9ZDBfOiv08BCGvF4WsJSqWUDUt7qtf2hEmjtVvo:LVM-9t8ITqLZa6AuuyVoz5Olp1KwF9ZDBfOiKf7XIiwdAYOJfaGhQe9fu26cTEICGgFS:LVM-9t8ITqLZa6AuuyVoz5Olp1KwF9ZDBfOiEZj7ZXbmrWDuGhd7vvi88VF0NdTMG8iA:CRYPT-LUKS1-797339213f684c929eb7d0aca4c6ba3e-luks-79733921-3f68-4c92-9eb7-d0aca4c6ba3e:LVM-9t8ITqLZa6AuuyVoz5Olp1KwF9ZDBfOi2rKredlBPnw2X7v1BiCuEpFo6gaE7BRw
:::::vg_hex-lv_home:vg_hex-lv_swap:vg_hex-lv_root:luks-79733921-3f68-4c92-9eb7-d0aca4c6ba3e:vg_hex-lv_images
:::::253:253:253:253:253
:::::2:0:1:4:3
:::::L--w:L--w:L--w:L--w:L--w
:::::1:2:1:1:1
:::::3:1:1:1:2
:::::0:0:0:0:0
:::::LVM-9t8ITqLZa6AuuyVoz5Olp1KwF9ZDBfOiv08BCGvF4WsJSqWUDUt7qtf2hEmjtVvo:LVM-9t8ITqLZa6AuuyVoz5Olp1KwF9ZDBfOiKf7XIiwdAYOJfaGhQe9fu26cTEICGgFS:LVM-9t8ITqLZa6AuuyVoz5Olp1KwF9ZDBfOiEZj7ZXbmrWDuGhd7vvi88VF0NdTMG8iA:CRYPT-LUKS1-797339213f684c929eb7d0aca4c6ba3e-luks-79733921-3f68-4c92-9eb7-d0aca4c6ba3e:LVM-9t8ITqLZa6AuuyVoz5Olp1KwF9ZDBfOi2rKredlBPnw2X7v1BiCuEpFo6gaE7BRw
Whenver reporting field name is registered with libdevmapper and if
the field name contains any number of underscores ('_'), libdm
can now automatically recognize any of its variant without any
underscores used.
For example:
..for underscores in prefixes:
pvs -o pv_name
pvs -o name
pvs -o pvname (newly recognized besides pvname)
..for underscores in the name:
lvs -o cache_mode
lvs -o cachemode
..or even multiple underscores:
pvs -o pv___na___me
It's all variant of the same field name.
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.
