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dm-integrity stores checksums of the data written to an
LV, and returns an error if data read from the LV does
not match the previously saved checksum. When used on
raid images, dm-raid will correct the error by reading
the block from another image, and the device user sees
no error. The integrity metadata (checksums) are stored
on an internal LV allocated by lvm for each linear image.
The internal LV is allocated on the same PV as the image.
Create a raid LV with an integrity layer over each
raid image (for raid levels 1,4,5,6,10):
lvcreate --type raidN --raidintegrity y [options]
Add an integrity layer to images of an existing raid LV:
lvconvert --raidintegrity y LV
Remove the integrity layer from images of a raid LV:
lvconvert --raidintegrity n LV
Settings
Use --raidintegritymode journal|bitmap (journal is default)
to configure the method used by dm-integrity to ensure
crash consistency.
Initialization
When integrity is added to an LV, the kernel needs to
initialize the integrity metadata/checksums for all blocks
in the LV. The data corruption checking performed by
dm-integrity will only operate on areas of the LV that
are already initialized. The progress of integrity
initialization is reported by the "syncpercent" LV
reporting field (and under the Cpy%Sync lvs column.)
Example: create a raid1 LV with integrity:
$ lvcreate --type raid1 -m1 --raidintegrity y -n rr -L1G foo
Creating integrity metadata LV rr_rimage_0_imeta with size 12.00 MiB.
Logical volume "rr_rimage_0_imeta" created.
Creating integrity metadata LV rr_rimage_1_imeta with size 12.00 MiB.
Logical volume "rr_rimage_1_imeta" created.
Logical volume "rr" created.
$ lvs -a foo
LV VG Attr LSize Origin Cpy%Sync
rr foo rwi-a-r--- 1.00g 4.93
[rr_rimage_0] foo gwi-aor--- 1.00g [rr_rimage_0_iorig] 41.02
[rr_rimage_0_imeta] foo ewi-ao---- 12.00m
[rr_rimage_0_iorig] foo -wi-ao---- 1.00g
[rr_rimage_1] foo gwi-aor--- 1.00g [rr_rimage_1_iorig] 39.45
[rr_rimage_1_imeta] foo ewi-ao---- 12.00m
[rr_rimage_1_iorig] foo -wi-ao---- 1.00g
[rr_rmeta_0] foo ewi-aor--- 4.00m
[rr_rmeta_1] foo ewi-aor--- 4.00m
Since we need to preserve allocated strings across 2 separate
activation calls of '_tree_action()' we need to use other mem
pool them dm->mem - but since cmd->mem is released between
individual lvm2 locking calls, we rather introduce a new separate
mem pool just for pending deletes with easy to see life-span.
(not using 'libmem' as it would basicaly keep allocations over
the whole lifetime of clvmd)
This patch is fixing previous commmit where the memory was
improperly used after pool release.
With previous patch 30a98e4d67 we
started to put devices one pending_delete list instead
of directly scheduling their removal.
However we have operations like 'snapshot merge' where we are
resuming device tree in 2 subsequent activation calls - so
1st such call will still have suspened devices and no chance
to push 'remove' ioctl.
Since we curently cannot easily solve this by doing just single
activation call (which would be preferred solution) - we introduce
a preservation of pending_delete via command structure and
then restore it on next activation call.
This way we keep to remove devices later - although it might be
not the best moment - this may need futher tunning.
Also we don't keep the list of operation in 1 trasaction
(unless we do verify udev symlinks) - this could probably
also make it more correct in terms of which 'remove' can
be combined we already running 'resume'.
Avoid having PVs with different logical block sizes in the same VG.
This prevents LVs from having mixed block sizes, which can produce
file system errors.
The new config setting devices/allow_mixed_block_sizes (default 0)
can be changed to 1 to return to the unrestricted mode.
The exported VG checking/enforcement was scattered and
inconsistent. This centralizes it and makes it consistent,
following the existing approach for foreign and shared
VGs/PVs, which are very similar to exported VGs/PVs.
The access policy that now applies to foreign/shared/exported
VGs/PVs, is that if a foreign/shared/exported VG/PV is named
on the command line (i.e. explicitly requested by the user),
and the command is not permitted to operate on it because it
is foreign/shared/exported, then an access error is reported
and the command exits with an error. But, if the command is
processing all VGs/PVs, and happens to come across a
foreign/shared/exported VG/PV (that is not explicitly named on
the command line), then the command silently skips it and does
not produce an error.
A command using tags or --select handles inaccessible VGs/PVs
the same way as a command processing all VGs/PVs, and will
not report/return errors if these inaccessible VGs/PVs exist.
The new policy fixes the exit codes on a somewhat random set of
commands that previously exited with an error if they were
looking at all VGs/PVs and an exported VG existed on the system.
There should be no change to which commands are allowed/disallowed
on exported VGs/PVs.
Certain LV commands (lvs/lvdisplay/lvscan) would previously not
display LVs from an exported VG (for unknown reasons). This has
not changed. The lvm fullreport command would previously report
info about an exported VG but not about the LVs in it. This
has changed to include all info from the exported VG.
and implement it based on a device, not based
on a pv struct (which is not available when the
device is not a part of the vg.)
currently only the vgremove command wipes outdated
pvs until more advanced recovery is added in a
subsequent commit
If udev info is missing for a device, (which would indicate
if it's an MD component), then do an end-of-device read to
check if a PV is an MD component. (This is skipped when
using hints since we already know devs in hints are good.)
A new config setting md_component_checks can be used to
disable the additional end-of-device MD checks, or to
always enable end-of-device MD checks.
When both hints and udev info are disabled/unavailable,
the end of PVs will now be scanned by default. If md
devices with end-of-device superblocks are not being
used, the extra I/O overhead can be avoided by setting
md_component_checks="start".
Save the previous duplicate PVs in a global list instead
of a list on the cmd struct. dmeventd reuses the cmd struct
for multiple commands, and the list entries between commands
were being freed (apparently), causing a segfault in dmeventd
when it tried to use items in cmd->unused_duplicate_devs
that had been saved there by the previous command.
There have been two file locks used to protect lvm
"global state": "ORPHANS" and "GLOBAL".
Commands that used the ORPHAN flock in exclusive mode:
pvcreate, pvremove, vgcreate, vgextend, vgremove,
vgcfgrestore
Commands that used the ORPHAN flock in shared mode:
vgimportclone, pvs, pvscan, pvresize, pvmove,
pvdisplay, pvchange, fullreport
Commands that used the GLOBAL flock in exclusive mode:
pvchange, pvscan, vgimportclone, vgscan
Commands that used the GLOBAL flock in shared mode:
pvscan --cache, pvs
The ORPHAN lock covers the important cases of serializing
the use of orphan PVs. It also partially covers the
reporting of orphan PVs (although not correctly as
explained below.)
The GLOBAL lock doesn't seem to have a clear purpose
(it may have eroded over time.)
Neither lock correctly protects the VG namespace, or
orphan PV properties.
To simplify and correct these issues, the two separate
flocks are combined into the one GLOBAL flock, and this flock
is used from the locking sites that are in place for the
lvmlockd global lock.
The logic behind the lvmlockd (distributed) global lock is
that any command that changes "global state" needs to take
the global lock in ex mode. Global state in lvm is: the list
of VG names, the set of orphan PVs, and any properties of
orphan PVs. Reading this global state can use the global lock
in sh mode to ensure it doesn't change while being reported.
The locking of global state now looks like:
lockd_global()
previously named lockd_gl(), acquires the distributed
global lock through lvmlockd. This is unchanged.
It serializes distributed lvm commands that are changing
global state. This is a no-op when lvmlockd is not in use.
lockf_global()
acquires an flock on a local file. It serializes local lvm
commands that are changing global state.
lock_global()
first calls lockf_global() to acquire the local flock for
global state, and if this succeeds, it calls lockd_global()
to acquire the distributed lock for global state.
Replace instances of lockd_gl() with lock_global(), so that the
existing sites for lvmlockd global state locking are now also
used for local file locking of global state. Remove the previous
file locking calls lock_vol(GLOBAL) and lock_vol(ORPHAN).
The following commands which change global state are now
serialized with the exclusive global flock:
pvchange (of orphan), pvresize (of orphan), pvcreate, pvremove,
vgcreate, vgextend, vgremove, vgreduce, vgrename,
vgcfgrestore, vgimportclone, vgmerge, vgsplit
Commands that use a shared flock to read global state (and will
be serialized against the prior list) are those that use
process_each functions that are based on processing a list of
all VG names, or all PVs. The list of all VGs or all PVs is
global state and the shared lock prevents those lists from
changing while the command is processing them.
The ORPHAN lock previously attempted to produce an accurate
listing of orphan PVs, but it was only acquired at the end of
the command during the fake vg_read of the fake orphan vg.
This is not when orphan PVs were determined; they were
determined by elimination beforehand by processing all real
VGs, and subtracting the PVs in the real VGs from the list
of all PVs that had been identified during the initial scan.
This is fixed by holding the single global lock in shared mode
while processing all VGs to determine the list of orphan PVs.
This reverts 518a8e8cfb
"lvmlockd: activate mirror LVs in shared mode with cmirrord"
because while activating a mirror LV with cmirrord worked,
changes to the active cmirror did not work.
When lvextend extends an LV that is active with a shared
lock, use this as a signal that other hosts may also have
the LV active, with gfs2 mounted, and should have the LV
refreshed to reflect the new size. Use the libdlmcontrol
run api, which uses dlm_controld/corosync to run an
lvchange --refresh command on other cluster nodes.
which defines the amount of memory that lvm will allocate
for bcache. Increasing this setting is required if it is
smaller than a single copy of VG metadata.
For users who do not want all of the fields included
in debug lines, let them specify in lvm.conf which
fields to include. timestamp, command[pid], and
file:line fields can all be disabled.
Without this, the output from different commands in a single
log file could not be separated.
Change the default "indent" setting to 0 so that the default
debug output does not include variable spaces in the middle
of debug lines.
Save the list of PVs in /run/lvm/hints. These hints
are used to reduce scanning in a number of commands
to only the PVs on the system, or only the PVs in a
requested VG (rather than all devices on the system.)
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.
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.
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.
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.
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.
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.)
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.
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.
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/
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.
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.
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.
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.)
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.
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.
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.
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....
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)
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.
. 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.
Make it easier to replace missing segments with 'zero' returning
target - otherwise user would have to create some extra target
to provide zeros as /dev/zero can't be used (not a block device).
Also break code loop when segment is found and make it an INTERNAL_ERROR
where it's missing.
We added lightweight toolcontext handle to avoid useless initialization
of some parts of the context and also to avoid problems when using the
handle very soon at system boot, like in lvm2-activation-generator
through lvm2app interface. However, we missed reading all the other
config sources like lvmlocal.conf as well as any tag config - we need to
read these too to get the final config value which may be overriden in
any of these additional config sources.
Currently, we use this lightweight toolcontext handle to read
global/use_lvmetad and global/use_lvmpolld config values in
lvm2-activation-generator using lvm2app interface (lvm_config_find_bool
lvm2app function).
Some settings are not suitable for override in interactive/shell
mode because such settings may confuse the code and it may end
up with unexpected behaviour. This is because of the fact that
once we're in the interactive/shell mode, we have already applied
some settings for the shell itself and we can't override them
further because we're already using those settings to drive the
interactive/shell mode. Such settings would get ignored silently
or, in worse case, they would mess up the existing configuration.
When lvm commands are executed in lvm shell, we cover the whole lvm
command execution within this shell now. That means, all messages logged
and status caught during each command execution is now recorded in the
log report, including overall command's return code.
With patches that will follow, this will make it possible to widen log
report coverage when commands are executed from lvm shell so the amount
of messages that may end up in stderr/stdout instead of log report are
minimized.
Currently, the output is separated in 3 parts and each part can go into
a separate and user-defined file descriptor:
- common output (stdout by default, customizable by LVM_OUT_FD environment variable)
- error output (stderr by default, customizable by LVM_ERR_FD environment variable)
- report output (stdout by default, customizable by LVM_REPORT_FD environment variable)
For example, each type of output goes to different output file:
[0] fedora/~ # export LVM_REPORT_FD=3
[0] fedora/~ # lvs fedora vg/abc 1>out 2>err 3>report
[0] fedora/~ # cat out
[0] fedora/~ # cat err
Volume group "vg" not found
Cannot process volume group vg
[0] fedora/~ # cat report
LV VG Attr LSize Layout Role CTime
root fedora -wi-ao---- 19.00g linear public Wed May 27 2015 08:09:21
swap fedora -wi-ao---- 500.00m linear public Wed May 27 2015 08:09:21
Another example in LVM shell where the report goes to "report" file:
[0] fedora/~ # export LVM_REPORT_FD=3
[0] fedora/~ # lvm 3>report
(in lvm shell)
lvm> vgs
(content of "report" file)
[1] fedora/~ # cat report
VG #PV #LV #SN Attr VSize VFree
fedora 1 2 0 wz--n- 19.49g 0
(in lvm shell)
lvm> lvs
(content of "report" file)
[1] fedora/~ # cat report
VG #PV #LV #SN Attr VSize VFree
fedora 1 2 0 wz--n- 19.49g 0
LV VG Attr LSize Layout Role CTime
root fedora -wi-ao---- 19.00g linear public Wed May 27 2015 08:09:21
swap fedora -wi-ao---- 500.00m linear public Wed May 27 2015 08:09:21
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.
Some commands scan labels to populate lvmcache multiple
times, i.e. lvmcache_init, scan labels to fill lvmcache,
lvmcache_destroy, then later repeat
Each time labels are scanned, duplicates are detected,
and preferred devices are chosen. Each time this is done
within a single command, we want to choose the same
preferred devices. So, check for existing preferences
when choosing preferred devices.
This also fixes a problem with the list of unused duplicate
devs when run in an lvm shell. The devs had been allocated
from cmd memory, resulting in invalid list entries between
commands.
A program may be using liblvm2app for simply checking a config
setting in lvm.conf. In this case, a full lvm context is not
needed, only cmd->cft (which are the config settings read from
lvm.conf).
lvm_config_find_bool() can now be passed a NULL lvm context
in which case it will only create cmd->cft, check the config
setting asked for, and destroy the cmd.
When setting up a toolcontext, the lib init function
was detecting an error when there was none, and then
it was returning an incompletely initialized cmd struct
instead of NULL. The effect was that the lib would try
to use the uninitialized cmd struct and segfault.
This would happen if a non-fatal error occurred during
cmd setup, e.g. user permission failed on lvmetad socket,
causing cmd to fall back to scanning and not use lvmetad.
The only real error condition is when create_toolcontext
returns NULL. If cmd is returned, the lib can use it.
If lvmetad is running, and a command opts to not use it
(--config global/use_lvmetad=0), and the command changes
metadata, then the metadata change is not visible to
lvmetad. Subsequent commands using lvmetad to change
metadata may cause corruption based on the invalid
lvmetad state.
Eventually we can set the disabled state in lvmetad
to prevent this problem, but for now print a warning
about the possibility.
When command is not using lvmetad because
use_lvmetad=0 in the config, but the lvmetad
pidfile exists, print a warning (previously
this checked for the socket existing instead
of the pidfile existing.)
The lvmetad connection is created within the
init_connections() path during command startup,
rather than via the old lvmetad_active() check.
The old lvmetad_active() checks are replaced
with lvmetad_used() which is a simple check that
tests if the command is using/connected to lvmetad.
The old lvmetad_set_active(cmd, 0) calls, which
stopped the command from using lvmetad (to revert to
disk scanning), are replaced with lvmetad_make_unused(cmd).
When a command modifies a PV or VG, or changes the
activation state of an LV, it will send a dbus
notification when the command is finished. This
can be enabled/disabled with a config setting.
This patch adds "include_historical_lvs" field to struct cmd_context to
make it possible for the command to switch between original funcionality
where no historical LVs are processed and functionality where historical
LVs are taken into account (and reported or processed further). The switch
between these modes is done using the '-H|--history' switch on command
line.
The include_historical_lvs state is then passed to process_each_* fns
using the "include_historical_lvs" field within struct processing_handle.
'verbose' was marked as a boolean option while it
takes integer args - so it has limited usage to 0 or 1,
but we supported 0-4 at least.
Fix it by switching to corrent int type.
(Hopefully noone was trying to use this variable as true/yes/false/no
way - as the would be unsupported/undocumented).
