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Commit Graph

368 Commits

Author SHA1 Message Date
David Teigland
3d2fd95af7 remove unused full filter
it's the same as cmd->filter
2018-12-04 14:06:46 -06:00
David Teigland
89c11a2b49 remove unused lvmetad filter 2018-12-04 12:44:43 -06:00
David Teigland
ca66d52032 io: use sync io if aio fails
io_setup() for aio may fail if a system has reached the
aio request limit.  In this case, fall back to using
sync io.  Also, lvm use of aio can be disabled entirely
with config setting global/use_aio=0.

The system limit for aio requests can be seen from
  /proc/sys/fs/aio-max-nr

The current usage of aio requests can be seen from
  /proc/sys/fs/aio-nr

The system limit for aio requests can be increased by
setting fs.aio-max-nr using sysctl.

Also add last-byte limit to the sync io code.
2018-11-20 09:13:20 -06:00
David Teigland
3ae5569570 Add dm-writecache support
dm-writecache is used like dm-cache with a standard LV
as the cache.

$ lvcreate -n main -L 128M -an foo /dev/loop0

$ lvcreate -n fast -L 32M -an foo /dev/pmem0

$ lvconvert --type writecache --cachepool fast foo/main

$ lvs -a foo -o+devices
  LV            VG  Attr       LSize   Origin        Devices
  [fast]        foo -wi-------  32.00m               /dev/pmem0(0)
  main          foo Cwi------- 128.00m [main_wcorig] main_wcorig(0)
  [main_wcorig] foo -wi------- 128.00m               /dev/loop0(0)

$ lvchange -ay foo/main

$ dmsetup table
foo-main_wcorig: 0 262144 linear 7:0 2048
foo-main: 0 262144 writecache p 253:4 253:3 4096 0
foo-fast: 0 65536 linear 259:0 2048

$ lvchange -an foo/main

$ lvconvert --splitcache foo/main

$ lvs -a foo -o+devices
  LV   VG  Attr       LSize   Devices
  fast foo -wi-------  32.00m /dev/pmem0(0)
  main foo -wi------- 128.00m /dev/loop0(0)
2018-11-06 14:18:41 -06:00
Zdenek Kabelac
13c49033ed cov: fix failing filter initialization
When persistent_filter_create() fails, the existing passed filter
should be preserved, so it could be properly deleted on
error path - so new pfilter is assigned instead.
2018-10-15 17:49:44 +02:00
David Teigland
bfcecbbce1 filter: add config setting to skip scanning LVs
devices/scan_lvs (default 1) determines whether lvm
will scan LVs for layered PVs.  The lvm behavior has
always been to scan LVs, but it's rare for LVs to have
layered PVs, and much more common for there to be many
LVs that substantially slow down scanning with no benefit.

This is implemented in the usable filter, and has the
same effect as listing all LVs in the global_filter.
2018-08-30 09:59:50 -05:00
David Teigland
8a66c81b9b lvconvert: restrict command matching for no option variant
The 'lvconvert LV' command def has caused multiple problems
for command matching because it matches the required options
of any lvconvert command.  Any lvconvert with incorrect options
ends up matching 'lvconvert LV', which then produces an error
about incorrect options being used for 'lvconvert LV'.  This
prevents suggestions from nearest-command partial command matches.

Add a special case for 'lvconvert LV' so that it won't be used
as a partial match for a command that has options specified.
2018-07-23 11:12:38 -05:00
David Teigland
117160b27e Remove lvmetad
Native disk scanning is now both reduced and
async/parallel, which makes it comparable in
performance (and often faster) when compared
to lvm using lvmetad.

Autoactivation now uses local temp files to record
online PVs, and no longer requires lvmetad.

There should be no apparent command-level change
in behavior.
2018-07-11 11:26:42 -05:00
Zdenek Kabelac
a8f84f7801 vdo: introduce segment types and manip functions
Core functionality introducing lvm VDO support.
2018-07-09 15:28:35 +02:00
David Teigland
15826214f9 Remove code for using files as devices
It appears this has not been used in a long time,
and it seems to have no point since loop devices exist.
2018-06-21 09:33:21 -05:00
David Teigland
428514a07f Drop --ignoreskippedcluster option
It's no longer needed.  Clustered VGs are now handled in
the same way as foreign VGs, and as shared VGs that
can't be accessed:

- A command processing all VGs sees a clustered VG,
  prints a message ("Skipping clustered VG foo."),
  skips it, and does not fail.

- A command where the clustered VG is explicitly
  named on the command line, prints a message and fails.
  "Cannot access clustered VG foo, see lvmlockd(8)."

The option is listed in the set of ignored options for
the commands that previously accepted it.  (Removing it
entirely would cause commands/scripts to fail if they
set it.)
2018-06-15 15:59:34 -05:00
David Teigland
328303d4d4 Remove unused device error counting 2018-06-15 14:04:39 -05:00
David Teigland
e53cfc6a88 lvmlockd: update method for changing clustered VG
The previous method for forcibly changing a clustered VG
to a local VG involved using -cn and locking_type 0.
Since those options are deprecated, replace it with
the same command used for other forced lock type changes:
vgchange --locktype none --lockopt force.
2018-06-13 15:30:28 -05:00
David Teigland
22c5467add filters: remove cache file in persistent filter
It creates problems because it's not always correct,
and it doesn't actually help much.
2018-06-13 14:00:47 -05:00
David Teigland
17f5572bc9 Remove independent metadata areas
in which metadata is stored in files on the local fs
instead of on PVs.
2018-06-13 12:25:19 -05:00
David Teigland
9df6f601e0 Remove code for loading other metadata formats
other formats are not used.
2018-06-13 12:03:42 -05:00
Joe Thornber
d5da55ed85 device_mapper: remove dbg_malloc.
I wrote dbg_malloc before we had valgrind.  These days there's just
no need.
2018-06-08 13:40:53 +01:00
David Teigland
e6bb780d24 Rework lock-override options and locking_type settings
The last commit related to this was incomplete:
  "Implement lock-override options without locking type"

This is further reworking and reduction of the locking.[ch]
layer which handled all clustering, but is now only used
for file locking.  The "locking types" that this layer
implemented were removed previously, leaving only the
standard file locking.  (Some cluster-related artifacts
remain to be cleared out later.)

Command options to override or modify locking behavior
are reimplemented here without using the locking types.
Also, deprecated locking_type values are recognized,
and implemented as if one of the equivalent override
options was set.

Options that override file locking are:

. --nolocking disables all file locking.

. --readonly grants read lock requests without actually
  taking a file lock, and refuses write lock requests.

. --ignorelockingfailure tries to set up file locks and
  uses them normally if possible.  When not possible, it
  behaves like --readonly, but allows activation.

. --sysinit is the same as ignorelockingfailure.

. global/metadata_read_only acquires actual read file
  locks, and refuses write lock requests.

(Some of these options could probably be deprecated
because they were added as workarounds to various
locking_type behaviors that are now deprecated.)

The locking_type setting now has one valid value: 1 which
refers to standard file locking.  Configs that contain
deprecated values are recognized and still work in
largely the same way:

. 0 disabled all locking, now implemented like --nolocking
  is set.  Allow the nolocking option in all commands.

. 1 is the normal file locking setting and is unchanged.

. 2 was for external locking which was not used, and
  reverts to normal file locking.

. 3 was for cluster/clvm.  This reverts to normal file
  locking, and prints messages about lvmlockd.

. 4 was equivalent to readonly, now implemented like
  --readonly is set.

. 5 disabled all locking, now implemented like
  --nolocking is set.
2018-06-07 16:47:15 -05:00
Heinz Mauelshagen
de66704253 segtype: add linear
Add linear segtype addressing FIXME in preparation
for linear <-> striped convenience conversion support
2018-06-05 16:23:18 +02:00
Joe Thornber
7f97c7ea9a build: Don't generate symlinks in include/ dir
As we start refactoring the code to break dependencies (see doc/refactoring.txt),
I want us to use full paths in the includes (eg, #include "base/data-struct/list.h").
This makes it more obvious when we're breaking abstraction boundaries, eg, including a file in
metadata/ from base/
2018-05-14 10:30:20 +01:00
David Teigland
57bb46c5e7 filter: use bcache for filter reads
Filters are still applied before any device reading or
the label scan, but any filter checks that want to read
the device are skipped and the device is flagged.

After bcache is populated, but before lvm looks for
devices (i.e. before label scan), the filters are
reapplied to the devices that were flagged above.
The filters will then find the data they need in
bcache.
2018-05-10 16:03:19 -05:00
David Teigland
c016b573ee clvmd: separate saved_vg from vginfo
The clvmd saved_vg data is independent from the normal lvm
lvmcache vginfo data, so separate saved_vg from vginfo.
Normal lvm doesn't need to use save_vg at all, and in clvmd,
lvmcache changes on vginfo can be made without worrying
about unwanted effects on saved_vg.
2018-05-03 14:54:48 -05:00
David Teigland
977d0a3613 filters: increase MAX_FILTERS for new filter
The new signature filter was added without increasing this.
2018-05-02 14:10:30 -05:00
David Teigland
24e7745d7a devices: ignore lvm1 and pool devices 2018-05-01 15:18:47 -05:00
David Teigland
c1cd18f21e Remove lvm1 and pool disk formats
There are likely more bits of code that can be removed,
e.g. lvm1/pool-specific bits of code that were identified
using FMT flags.

The vgconvert command can likely be reduced further.

The lvm1-specific config settings should probably have
some other fields set for proper deprecation.
2018-04-30 16:55:02 -05:00
David Teigland
4670e9f698 skip some clvmd-specific code in common cases
This, or something like it, can probably be done
in many other places.
2018-04-25 16:40:08 -05:00
David Teigland
aee27dc7ba scan: skip device rescan in vg_read
For reporting commands (pvs,vgs,lvs,pvdisplay,vgdisplay,lvdisplay)
we do not need to repeat the label scan of devices in vg_read if
they all had matching metadata in the initial label scan.  The
data read by label scan can just be reused for the vg_read.
This cuts the amount of device i/o in half, from two reads of
each device to one.  We have to be careful to avoid repairing
the VG if we've skipped rescanning.  (The VG repair code is very
poor, and will be redone soon.)
2018-04-20 11:23:14 -05:00
David Teigland
c0973e70a5 dev_cache: clean up scan
Pull out all of the twisted logic and simply call dev_cache_scan
at the start of the command prior to label scan.
2018-04-20 11:22:48 -05:00
David Teigland
d9a77e8bb4 lvmcache: simplify metadata cache
The copy of VG metadata stored in lvmcache was not being used
in general.  It pretended to be a generic VG metadata cache,
but was not being used except for clvmd activation.  There
it was used to avoid reading from disk while devices were
suspended, i.e. in resume.

This removes the code that attempted to make this look
like a generic metadata cache, and replaces with with
something narrowly targetted to what it's actually used for.

This is a way of passing the VG from suspend to resume in
clvmd.  Since in the case of clvmd one caller can't simply
pass the same VG to both suspend and resume, suspend needs
to stash the VG somewhere that resume can grab it from.
(resume doesn't want to read it from disk since devices
are suspended.)  The lvmcache vginfo struct is used as a
convenient place to stash the VG to pass it from suspend
to resume, even though it isn't related to the lvmcache
or vginfo.  These suspended_vg* vginfo fields should
not be used or touched anywhere else, they are only to
be used for passing the VG data from suspend to resume
in clvmd.  The VG data being passed between suspend and
resume is never modified, and will only exist in the
brief period between suspend and resume in clvmd.

suspend has both old (current) and new (precommitted)
copies of the VG metadata.  It stashes both of these in
the vginfo prior to suspending devices.  When vg_commit
is successful, it sets a flag in vginfo as before,
signaling the transition from old to new metadata.

resume grabs the VG stashed by suspend.  If the vg_commit
happened, it grabs the new VG, and if the vg_commit didn't
happen it grabs the old VG.  The VG is then used to resume
LVs.

This isolates clvmd-specific code and usage from the
normal lvm vg_read code, making the code simpler and
the behavior easier to verify.

Sequence of operations:

- lv_suspend() has both vg_old and vg_new
  and stashes a copy of each onto the vginfo:
  lvmcache_save_suspended_vg(vg_old);
  lvmcache_save_suspended_vg(vg_new);

- vg_commit() happens, which causes all clvmd
  instances to call lvmcache_commit_metadata(vg).
  A flag is set in the vginfo indicating the
  transition from the old to new VG:
  vginfo->suspended_vg_committed = 1;

- lv_resume() needs either vg_old or vg_new
  to use in resuming LVs.  It doesn't want to
  read the VG from disk since devices are
  suspended, so it gets the VG stashed by
  lv_suspend:
  vg = lvmcache_get_suspended_vg(vgid);

If the vg_commit did not happen, suspended_vg_committed
will not be set, and in this case, lvmcache_get_suspended_vg()
will return the old VG instead of the new VG, and it will
resume LVs based on the old metadata.
2018-04-20 11:22:45 -05:00
David Teigland
e3e5beec74 lvmetad: use new label_scan for update from pvscan
Take advantage of the common implementation with aio
and reduced disk reads.
2018-04-20 11:22:43 -05:00
David Teigland
a7cb76ae94 scan: use bcache for label scan and vg read
New label_scan function populates bcache for each device
on the system.

The two read paths are updated to get data from bcache.

The bcache is not yet used for writing.  bcache blocks
for a device are invalidated when the device is written.
2018-04-20 11:19:24 -05:00
Joe Thornber
00f1b208a1 [io paths] Unpick agk's aio stuff 2018-04-20 11:03:58 -05:00
Zdenek Kabelac
55d83f9f6e mirror: block_on_error only with monitoring
When user configured lvm2 to NOT user monitoring, activated mirror
actually hang upon error and it's quite unusable moment.

So instead Warn those 'brave' non-monitoring users about possible
problem and activation mirror without blocking error handling.

This also makes it a bit simpler for test suite to handle trouble
cases when test is running without  dmeventd.
2018-04-20 12:13:51 +02:00
Zdenek Kabelac
112846ce0b activation: support activation of component LVs
Occasionaly users may need to peek into 'component devices.
Normally lvm2 does not let users activation component.

This patch adds special mode where user can activate
component LV in a 'read-only' mode i.e.:

lvchange -ay vg/pool_tdata

All devices can be deactivated with:

lvchange -an vg  |  vgchange -an....
2018-03-06 15:42:46 +01:00
Zdenek Kabelac
12fba201be cleanup: detect dmeventd_executable just once
Avoid repeating debug messages about dmeventd executable
and just remember it once for whole cmd lifetime.
2018-02-12 22:14:25 +01:00
Zdenek Kabelac
afdbb28f72 toolcontext: light context missed to set-up mem mempool
If cmd->mem was null, then systemd generator was failing on:

(gdb) bt
dm_pool_alloc_aligned (p=0x0, s=96, alignment=8) at mm/pool-fast.c:95
dm_pool_alloc (p=0x0, s=96) at mm/pool-fast.c:90
dm_pool_zalloc (p=0x0, s=96) at mm/pool.c:74
config_file_read_fd (mem=0x0, cft=0x55f4339dbad0, dev=0x55f4339dfac0, reason=DEV_IO_MDA_CONTENT, offset=0, size=82293, offset2=0, size2=0,
    checksum_fn=0x0, checksum=0, checksum_only=0, no_dup_node_check=0, ioflags=0, config_file_read_fd_callback=0x0, config_file_read_fd_context=0x0) at config/config.c:567
config_file_read (mem=0x0, cft=0x55f4339dbad0) at config/config.c:658
config_file_open_and_read (config_file=0x7f49aef14540 <config_file> "/var/tmp/lvm/etc/lvm/lvm.conf", source=CONFIG_FILE, cmd=0x55f4339d6260)
    at config/config.c:282
_load_config_file (cmd=0x55f4339d6260, tag=0x7f49aeca15da "", local=0) at commands/toolcontext.c:824
_init_lvm_conf (cmd=0x55f4339d6260) at commands/toolcontext.c:853
create_config_context () at commands/toolcontext.c:1814
lvm_config_find_bool (libh=0x0, config_path=0x55f431a884ad "global/use_lvmetad", fail=0) at lvm_base.c:144
main ()
2018-02-12 22:13:53 +01:00
Zdenek Kabelac
83258e3385 toolcontext: do not change stream for pthreaded programs
With pthreaded daemons like 'dmeventd' using  liblvm via plugin,
lvm2 actually should not 'play' with streams at all - as there
could be parallel outputs running.

As a current quick workaround just disable change for pthreaded
program (gettid() != getpid()).

TODO: it's possible the change of buffering actually doesn't serve us
any measurable benefit and could be dropped as whole later...

Meanwhile this patch is fixing this occasional valgrind race report:

Invalid read of size 4
   at 0x571892C: vfprintf (in /usr/lib64/libc-2.26.9000.so)
   by 0x57216B3: fprintf (in /usr/lib64/libc-2.26.9000.so)
   by 0x5042886: dm_event_log (libdevmapper-event.c:925)
   by 0x10B015: _dmeventd_log (dmeventd.c:125)
   by 0x10D289: _unregister_for_event (dmeventd.c:1146)
   by 0x10E52E: _handle_request (dmeventd.c:1583)
   by 0x10E6D7: _do_process_request (dmeventd.c:1631)
   by 0x10E7C6: _process_request (dmeventd.c:1660)
   by 0x1101A4: main (dmeventd.c:2285)
 Address 0x6264d30 is 192 bytes inside a block of size 552 free'd
   at 0x4C2ED68: free (vg_replace_malloc.c:530)
   by 0x573907D: fclose@@GLIBC_2.2.5 (in /usr/lib64/libc-2.26.9000.so)
   by 0x6AC5C00: reopen_standard_stream (log.c:189)
   by 0x6A8E62C: destroy_toolcontext (toolcontext.c:2271)
   by 0x6BA5C22: lvm_fin (lvmcmdline.c:3339)
   by 0x6BD5EF3: lvm2_exit (lvmcmdlib.c:123)
   by 0x6856013: dmeventd_lvm2_exit (dmeventd_lvm.c:103)
   by 0x66535B8: unregister_device (dmeventd_thin.c:432)
   by 0x10CBBC: _do_unregister_device (dmeventd.c:926)
   by 0x10CD74: _monitor_unregister (dmeventd.c:979)
   by 0x10D094: _monitor_thread (dmeventd.c:1066)
   by 0x54B35E0: start_thread (in /usr/lib64/libpthread-2.26.9000.so)
   by 0x57C30EE: clone (in /usr/lib64/libc-2.26.9000.so)
 Block was alloc'd at
   at 0x4C2DBBB: malloc (vg_replace_malloc.c:299)
   by 0x573932B: fdopen@@GLIBC_2.2.5 (in /usr/lib64/libc-2.26.9000.so)
   by 0x6AC5DC2: reopen_standard_stream (log.c:200)
   by 0x6A8D11D: create_toolcontext (toolcontext.c:1898)
   by 0x6BA5B6B: init_lvm (lvmcmdline.c:3319)
   by 0x6BD5BC8: cmdlib_lvm2_init (lvmcmdlib.c:34)
   by 0x6BD5F04: lvm2_init (lvm2cmd.c:20)
   by 0x6855EA7: dmeventd_lvm2_init (dmeventd_lvm.c:67)
   by 0x665305F: register_device (dmeventd_thin.c:352)
   by 0x10CB7A: _do_register_device (dmeventd.c:916)
   by 0x10CEE4: _monitor_thread (dmeventd.c:1006)
   by 0x54B35E0: start_thread (in /usr/lib64/libpthread-2.26.9000.so)
   by 0x57C30EE: clone (in /usr/lib64/libc-2.26.9000.so)
....
Process terminating with default action of signal 6 (SIGABRT): dumping core
   at 0x570016B: raise (in /usr/lib64/libc-2.26.9000.so)
   by 0x5701520: abort (in /usr/lib64/libc-2.26.9000.so)
   by 0x57437D8: __libc_message (in /usr/lib64/libc-2.26.9000.so)
   by 0x5743831: __libc_fatal (in /usr/lib64/libc-2.26.9000.so)
   by 0x5744056: _IO_vtable_check (in /usr/lib64/libc-2.26.9000.so)
   by 0x574751C: __overflow (in /usr/lib64/libc-2.26.9000.so)
   by 0x574191A: fputc (in /usr/lib64/libc-2.26.9000.so)
   by 0x50428E3: dm_event_log (libdevmapper-event.c:934)
   by 0x10B015: _dmeventd_log (dmeventd.c:125)
   by 0x10D289: _unregister_for_event (dmeventd.c:1146)
   by 0x10E52E: _handle_request (dmeventd.c:1583)
   by 0x10E6D7: _do_process_request (dmeventd.c:1631)
   by 0x10E7C6: _process_request (dmeventd.c:1660)
   by 0x1101A4: main (dmeventd.c:2285)
2018-02-09 10:56:40 +01:00
Alasdair G Kergon
8c7bbcfb0f device: Basic config and setup to support async I/O. 2018-02-08 20:15:14 +00:00
Alasdair G Kergon
4b9806ab6f toolcontext: Add paired label_init to refresh_toolcontext.
label_init() and label_exit() should be paired.
2018-01-02 22:00:31 +00:00
Alasdair G Kergon
22b6c482ec config: Split config buffer processing into new fn.
Wrap its parameters into struct process_config_file_params allocated
from a mempool now passed into the config_file_read* fns.
2018-01-02 21:10:46 +00:00
Zdenek Kabelac
110dac870c cleanup: use existing define with prefix 2017-12-04 15:38:50 +01:00
Alasdair G Kergon
02e9876665 log: Add io debug class 2017-11-15 01:02:15 +00:00
Alasdair G Kergon
f1cc5b12fd tidy: Add missing underscores to statics. 2017-10-18 15:58:13 +01:00
David Teigland
6ac1e04b3a replicator: remove the code
It has not been used in a long time and is not
expected to be used further.
2017-10-13 16:20:42 -05:00
David Teigland
518a8e8cfb lvmlockd: activate mirror LVs in shared mode with cmirrord
Previously lvmlockd disallowed mirror LVs to be activated
in shared mode.
2017-09-20 09:55:34 -05:00
Alasdair G Kergon
3654f478e1 toolcontext: Improve invalid units error message. 2017-07-27 00:51:50 +01:00
David Teigland
013c080756 command struct: remove command name refs
Change run time access to the command_name struct
cmd->cname instead of indirectly through
cmd->command->cname. This removes the two run time
fields from struct command.
2017-02-13 08:20:10 -06:00
David Teigland
1e2420bca8 commands: new method for defining commands
. Define a prototype for every lvm command.
. Match every user command with one definition.
. Generate help text and man pages from them.

The new file command-lines.in defines a prototype for every
unique lvm command.  A unique lvm command is a unique
combination of: command name + required option args +
required positional args.  Each of these prototypes also
includes the optional option args and optional positional
args that the command will accept, a description, and a
unique string ID for the definition.  Any valid command
will match one of the prototypes.

Here's an example of the lvresize command definitions from
command-lines.in, there are three unique lvresize commands:

lvresize --size SizeMB LV
OO: --alloc Alloc, --autobackup Bool, --force,
--nofsck, --nosync, --noudevsync, --reportformat String, --resizefs,
--stripes Number, --stripesize SizeKB, --poolmetadatasize SizeMB
OP: PV ...
ID: lvresize_by_size
DESC: Resize an LV by a specified size.

lvresize LV PV ...
OO: --alloc Alloc, --autobackup Bool, --force,
--nofsck, --nosync, --noudevsync,
--reportformat String, --resizefs, --stripes Number, --stripesize SizeKB
ID: lvresize_by_pv
DESC: Resize an LV by specified PV extents.
FLAGS: SECONDARY_SYNTAX

lvresize --poolmetadatasize SizeMB LV_thinpool
OO: --alloc Alloc, --autobackup Bool, --force,
--nofsck, --nosync, --noudevsync,
--reportformat String, --stripes Number, --stripesize SizeKB
OP: PV ...
ID: lvresize_pool_metadata_by_size
DESC: Resize a pool metadata SubLV by a specified size.

The three commands have separate definitions because they have
different required parameters.  Required parameters are specified
on the first line of the definition.  Optional options are
listed after OO, and optional positional args are listed after OP.

This data is used to generate corresponding command definition
structures for lvm in command-lines.h.  usage/help output is also
auto generated, so it is always in sync with the definitions.

Every user-entered command is compared against the set of
command structures, and matched with one.  An error is
reported if an entered command does not have the required
parameters for any definition.  The closest match is printed
as a suggestion, and running lvresize --help will display
the usage for each possible lvresize command.

The prototype syntax used for help/man output includes
required --option and positional args on the first line,
and optional --option and positional args enclosed in [ ]
on subsequent lines.

  command_name <required_opt_args> <required_pos_args>
          [ <optional_opt_args> ]
          [ <optional_pos_args> ]

Command definitions that are not to be advertised/suggested
have the flag SECONDARY_SYNTAX.  These commands will not be
printed in the normal help output.

Man page prototypes are also generated from the same original
command definitions, and are always in sync with the code
and help text.

Very early in command execution, a matching command definition
is found.  lvm then knows the operation being done, and that
the provided args conform to the definition.  This will allow
lots of ad hoc checking/validation to be removed throughout
the code.

Each command definition can also be routed to a specific
function to implement it.  The function is associated with
an enum value for the command definition (generated from
the ID string.)  These per-command-definition implementation
functions have not yet been created, so all commands
currently fall back to the existing per-command-name
implementation functions.

Using per-command-definition functions will allow lots of
code to be removed which tries to figure out what the
command is meant to do.  This is currently based on ad hoc
and complicated option analysis.  When using the new
functions, what the command is doing is already known
from the associated command definition.
2017-02-13 08:20:10 -06:00
Zdenek Kabelac
ec93f37b86 toolcontext: action for LVM_RUN_BY_DMEVENTD env var
When LVM_RUN_BY_DMEVENTD is set to 1, ensure there will
be no interaction with dmeventd.
2017-01-23 14:55:47 +01:00
Zdenek Kabelac
4a7f2155c1 clean: move code to lib part
Move actual processing part of the lvm2_disable_dmeventd_monitoring()
into a /lib part so we can reuse the code later for other cases.
2017-01-23 14:55:28 +01:00