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Since execve passed only NULL as environ, we had lost all environment vars on
restart - thus actually running 'different' clvmd then the one at start.
Preserving environ allows to restart clvmd with the same settings
(i.e. LD_LIBRARY_PATH)
Add test for second restart.
Add named cluster_ops to easily learn the name of the active cluster manager,
so we are able to restart singlenode manager in testing.
Add simple test for clvmd -S (restart) and -R (refresh)
(though it needs some extensions).
Read 2 environmental vars to learn about overide position for
CLVMD and LVM binaries.
We support LVM_BINARY in other script - and this way we could easily
test restart in our test-suite.
Bugfix:
Add (most probably unfinished) support for -E arg with list of exclusive
locks. (During clvmd restart all exclusive locks would have been lost and
in fact, if there would have been an exclusive lock, usage text would be
printed and clvmd exits.)
Instead of parsing list options multiple times every time some lock UUID is
checked - put them straight into the hash table - make the code easier to
understand as well.
Remove was_ex_lock() function (replaced with dm_hash_lookup()).
Swap return value for get_initial_state() (1 means success).
Update man pages and usage info for -E option.
Patch fixes Clang warnings about possible access via lv_name NULL pointer.
Replaces allocation of memory (strdup) with just pointer assignment
(since execve is being called anyway).
Checks for !*lv_name only when lv_name is defined.
(and as I'm not quite sure what state this really is - putting a FIXME
around - as this rather looks suspicios ??).
Add debug print of passed clvmd args.
Move the free_vg() to vg.c and replace free_vg with release_vg
and make the _free_vg internal.
Patch is needed for sharing VG in vginfo cache so the release_vg function name
is a better fit here.
are affected by the move. (Currently it's possible for I/O to become
trapped between suspended devices amongst other problems.
The current fix was selected so as to minimise the testing surface. I
hope eventually to replace it with a cleaner one that extends the
deptree code.
Some lvconvert scenarios still suffer from related problems.
allocates these buffers in such way it adds memory page for each such buffer
and size of unlock memory check will mismatch by 1 or 2 pages.
This happens when we print or read lines without '\n' so these buffers are
used. To avoid this extra allocation, use setvbuf to set these bufffers ahead.
Signed-off-by: Zdenek Kabelac <zkabelac@redhat.com>
Reviewed-by: Milan Broz <mbroz@redhat.com>
Reviewed-by: Petr Rockai <prockai@redhat.com>
'a small step' towards cleaner shutdown sequence.
Normally clvmd doens't care about unreleased memory on exit -
but for valgrind testing it's better to have them cleaned all.
So - few things are left on exit path - this patch starts to remove
just some of them.
1. lvm_thread_fs is made as a thread which could be joined on exit()
2. memory allocated to local_clien_head list is released.
(this part is somewhat more complex if the proper reaction is
needed - and as it requires some heavier code moving - it will
be resolved later.
Fix 2 more functions sending cluster messages to avoid passing uninitilised bytes
and compensate 1 extra byte attached to the message from the clvm_header.args[1]
member variable.
Fixing few issues:
struct clvm_header contains 'char args[1]' - so adding '+ 1' here
for message length calculation is 1 byte off.
Message with last byte uninitialized is then passed to write function.
Update also related arglen.
Initialise xid and clintid to 0.
Memory allocation is checked for NULL
- returned char not needed to be explicitly const
- warn if pipe() fails in clvmd (more fixes here needed for error paths...)
- assign (and ignore) read() output in drain buffer
Fixing some const warnings - with API change in:
int vg_extend(struct volume_group *vg, int pv_count, const char *const *pv_names,
Change is needed - as lvm2api expects const behaviour here.
So vg_extend() is doing local strdup for unescaping.
skip_dev_dir return const char* from const char* vg_name.
Rest of the patch is cleanup of related warnings.
Also using dm_report_filed_string() API change to simplify
casting in _string_disp and _lvname_disp.
New strategy for memory locking to decrease the number of call to
to un/lock memory when processing critical lvm functions.
Introducing functions for critical section.
Inside the critical section - memory is always locked.
When leaving the critical section, the memory stays locked
until memlock_unlock() is called - this happens with
sync_local_dev_names() and sync_dev_names() function call.
memlock_reset() is needed to reset locking numbers after fork
(polldaemon).
The patch itself is mostly rename:
memlock_inc -> critical_section_inc
memlock_dec -> critical_section_dec
memlock -> critical_section
Daemons (clmvd, dmevent) are using memlock_daemon_inc&dec
(mlockall()) thus they will never release or relock memory they've
already locked memory.
Macros sync_local_dev_names() and sync_dev_names() are functions.
It's better for debugging - and also we do not need to add memlock.h
to locking.h header (for memlock_unlock() prototyp).
results in clvmd deadlock
When a logical volume is activated exclusively in a cluster, the
local (non-cluster-aware) target is used. However, when creating
a snapshot on the exclusive LV, the resulting suspend/resume fails
to load the appropriate device-mapper table - instead loading the
cluster-aware target.
This patch adds an 'exclusive' parameter to the pertinent resume
functions to allow for the right target type to be loaded.
activated.
In order to achieve this, we need to be able to query whether
the origin is active exclusively (a condition of being able to
add an exclusive snapshot).
Once we are able to query the exclusive activation of an LV, we
can safely create/activate the snapshot.
A change to 'hold_lock' was also made so that a request to aquire
a WRITE lock did not replace an EX lock, which is already a form
of write lock.
Remove temporaly added fs_unlock() calls to fix clmvd usablity.
Now when the message passing is properly working - they are no longer needed.
Simplify no_locking check for VG unlock - as message is always send
for all targets - clustered & non-clustered.
Thanks to CLVMD_CMD_SYNC_NAMES propagation fix the message passing started
to work. So starts to send a message before the VG is unlocked.
Removing also implicit sync in VG unlock from clmvd as now the message
is delievered and processed in do_command().
Also add support for this new message into external locking
and mask this event from further processing.
This is better way how to fix clustered synchronization with udev.
As the code for message passing needs fixed - put currently
fs_unlock() after every active/deactive command in clvmd to
ensure nodes are properly created in time.
Instead of implicitly syncing udev operation in clustered and
file locking code - call synchronization directly in lock_vol() when
the operation unlocks VG
The problem is missing implicit fs_unlock() in the no_locking code.
This is used with --sysinit on read-only filesystem locking dir.
In this case vgchange -ay could exit before all udev nodes are properly
synchronised and may cause problems with accessing such node right after
vgchange --sysinint command is finished.
Add test case for vgchange --sysinit.
return lockspace reference (even if lockspace already exists)
and thus increases DLM lockspace count. It means that after
clvmd restart the lockspace is still in use.
(The only way to clean environment to enable clean cluster
shutdown is call "dlm_tool leave clvmd" several times.)
Because only one clvmd can run in time, we can use simpler logic,
try to open lockspace with dlm_open_lockspace() and only if it fails
try to create new one. This way the lockspace reference doesn not
increase.
Very easily reproducible with "clvmd -S" command.
Patch also fixes return code when clvmd_restart fails and fixes
double free if debug option was specified during restart.
Fixes https://bugzilla.redhat.com/show_bug.cgi?id=612862
Stop calling fs_unlock() from lv_de/activate().
Start using internal lvm fs cookie for dm_tree.
Stop directly calling dm_udev_wait() and
dm_tree_set/get_cookie() from activate code -
it's now called through fs_unlock() function.
Add lvm_do_fs_unlock()
Call fs_unlock() when unlocking vg where implicit unlock solves the
problem also for cluster - thus no extra command for clustering
environment is required - only lvm_do_fs_unlock() function is added
to call lvm's fs_unlock() while holding lvm_lock mutex in clvmd.
Add fs_unlock() also to set_lv() so the command waits until devices
are ready for regular open (i.e. wiping its begining).
Move fs_unlock() prototype to activation.h to keep fs.h private
in lib/activate dir and not expose other functions from this header.
Call for pthread_join() does not set errno value even though return values
looks like that. For now assign errno from return value and still use
strerror() to print some error message as this seems to be commonly used.
Add also log_sys_error() message for error close of local pipe.
As ternary operator has lower priority then add operation, this check
was not doing what seemed to be expected.
So enclose the test in braces and check for NULL in *buf.
We need to be sure that /var/run and /var/lock is always there.
(E.g. these two directories could be using tmpfs which then loose
all the content after reboot.)
Detect existence of new SELinux selabel interface during configure.
Use new dm_prepare_selinux_context instead of dm_set_selinux_context.
We should set the SELinux context before the actual file system object creation.
The new dm_prepare_selinux_context function sets this using the selabel_lookup
fn in conjuction with the setfscreatecon fn. If selinux/label.h interface
(that should be a part of the selinux library) is not found during configure,
we fallback to the original matchpathcon function instead.
LCK_CACHE is defined as 0x100 so it cannot be passed through
unsigned char parameter - remove it from the sprintf code.
If the LCK_CLUSTER should be printed here - lot of code need
to be reworked - so adding FIXME comment.
The management threads (main_loop, the socket thread) could close a single fd
twice in a row sometimes. At least one other thread can be running at the same
time as the threads doing the double close. That one running thread also
happens to do some IO (namely, open /proc/devices, read from it, close it). If
there was enough "demand" for the local socket, this could happen:
- a connection to clvmd is about to finish, let's say the fd is 13 (it often
happens to be in my test script, don't ask why)
- the local_sock thread calls close(13)
- the lvm thread calls open("/proc/devices"...) and gets 13
- the main_loop thread calls close(13) [OOPS!]
- new connection arrives, and is accept'd by a (new) local_sock thread
- the accept gives an fd of 13 (since it's the lowest free fd at this point)
- the lvm thread gets around to read from it's /proc/devices handle... 13,
again
- the lvm thread hangs forever trying to read from the socket instead of
/proc/devices
Signed-off-by: Petr Rockai <prockai@redhat.com>
Reviewed-by: Milan Broz <mbroz@redhat.com>
It's quite new feature which is not supported by older compilers.
So until some better macros are introduced into LVM code - hotfix current
compilation problems and compile this code only for __clang__ defining compilers.
The signalling code (pthread_cond_signal/pthread_cond_wait) in the
pre_and_post_thread was using the wait mutex (see man pthread_cond_wait)
incorrectly, and this could cause clvmd to deadlock when timing was
right. Detailed explanation of the problem follows.
There is a single mutex around (L for Lock, U for Unlock), a signal (S) and a
wait (W). C for pthread_create. Time flows from left to right, each arrow is a
thread.
So first the "naive" scenario, with no mutex (PPT = pre_and_post_thread, MCT =
main clvmd thread; well actually the thread that does read_from_local_sock). I
will also use X, for a moment when MCT actually waits for something to happen
that PPT was supposed to do.
MCT -----C ------S--X-----S----X----------------------S------XXXXXXXXX
| everything OK up to this --> <-- point...
PPT -----WWW-----WWWW------------------------------WWWWWWWWWWWWW
Ok, so pthread API actually does not let you use W/S like that. It goes out of
its way to tell you that you need a mutex to protect the W so that the above
cannot happen. *But* if you are creative and just lock around the W's and S's,
this happens:
MCT ----C-----LSU----X-----LSU----X------------LSU------XXXXXXX
|
PPT ---LWWWU-------LWWWWU-----------------------LWWWWWWWWW
Ooops. Nothing changed (the above is what actually was done by clvmd before
this satch). So let's do it differently, holding L locked *all* the time in
PPT, unless we are actually in W (this is something that the pthread API does
itself, see the man page).
MCT ----C-----LSU------X---LSU---X-----LLLLLLLSU----X----
| (and they live happily ever after)
PPT L---WWWWW---------WWWW----------------W----------
So W actually ensures that L is unlocked *atomically* together with entering
the wait. That means that unless PPT is actually waiting, it cannot be
signalled by MCT. So if MCT happens to signal it too soon (it wasn't waiting
yet), it (MCT) will be blocked on the mutex (L), until PPT is actually ready to
do something.
In all top vg read functions only LCK_VG_READ/WRITE can be used.
All other vg lock definitions are low-level backend machinery.
Moreover, LCK_WRITE cannot be tested through bitmask.
This patch fixes these mistakes.
For _recover_vg() we do not need lock_flags, it can be only
two of above and we always upgrading to LCK_VG_WRITE lock there.
(N.B. that code is racy)
There is no functional change in code (despite wrong masking
it produces correct bits:-)
Ignore snapshots when performing mirror recovery beneath an origin.
Pass LCK_ORIGIN_ONLY flag around cluster.
Add suspend_lv_origin and resume_lv_origin using LCK_ORIGIN_ONLY.
Switch dmeventd to use dm_create_lockfile and drop duplicate code.
Allow clvmd pidfile to be configurable.
Switch cmirrord and clvmd to use dm_create_lockfile.
Moreover, in current mirror handling, when it calls activate
on removed but suspended detached log this counter drops below zero
and confuses debug log.
When a mirror is being downconverted in a cluster, a series of suspends and
resumes is executed.
With the change to using UUIDs in dev_manager instead of names, the behaviour
has changed with regards to including an _mlog in the deptree of a logical
volume. In the old (pre-UUID-enabled) code, the _mlog would appear in a deptree
of any volume purely based on a name match: a linear volume foo would include
foo_mlog in its dependencies if that happened to exist. This behaviour was
fixed and the mlog is now only included for mirrors.
By a coincidence, this mlog bug had been hiding a different bug in clvmd. When
a mirror is being dismantled (and converted to a linear volume), it is first
suspended as a whole, then later resumed in parts. Nevertheless, the overall
memlock balance is maintained in this operation. The problem kicks in, because
even though the mirror log was suspended as part of the mirror, when the
dismantled mirror is resumed again, it is no longer a mirror and therefore the
mirror log stays suspended. This would not be a problem in itself, since
_delete_lv (from metadata/mirror.c) is called on it subsequently, which does an
activate/deactivate cycle and removes the LV. The activate/deactivate cycle
correctly prompts clvmd to resume the device: however, in doing this, it will
issue an unpaired resume operation (the suspend that caused the mirror log to
be suspended is paired with resuming the dismantled mirror later). We have
concluded that the path in clvmd should never affect memlock_count, since there
should never be an unmatched explicit suspend preceding this resume.
Because execve stops the command loop,
we never receive response (only socket close) for clvmd -S,
so waiting for response here makes no sense.
But if the calling process (clvmd -S) exits too early, connection
is closed from client side, clvmd takes this as an error and
never run restart code.
Ugly hack(TM).
Code is mixing up internal DLM and LVM definitions of lock
modes and flags.
OpenAIS and singlenode locking do not depend on DLM but
code currently cannot be compiled without libdlm.h!
LCK_* flags is LVM abstraction, used through all the code.
Only low-level backend (clvmd-cman etc) should use DLM definitions,
also this code should do all needed conversions.
Because there are two DLM flags used in generic code
(NOQUEUE, CONVERT) we define it similar way like lock modes.
(So all needed binary-compatible flags are on one place in locking.h)
(Further code cleaning still needed, though:-)
- allocate environment dynamically (still missing some limit?)
- try to recover, if destroy failed (do not destroy lvm here) and free memory
- check strdup() return codes
- report failure to log
- do not print NULL in exclusive lock loop
