Fix: handle concurrent flush vs get_next_subbuf on metadata cache

The "flush" operation can be performed on the metadata file descriptor
concurrently with get_next_subbuffer operations by different processes
(e.g. lttng session daemon issuing flush at "stop" concurrently with
consumer daemon issuing get_next_subbuf for metadata I/O). We need
to protect the metadata cache from those concurrent use by introducing a
mutex.

This fixes a race where metadata from a kernel trace is corrupted due to
this scenario. The corruption shows up like the same metadata content (a
metadata packet) being written twice consecutively in the metadata
stream, thus triggering a babeltrace "parse error" when trying to read
the trace.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Modernize README using Markdown

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: OOT lttng_logger tracepoint not visible with signed kernels

For the same reason as commit dd8d5afb3fabf853cb4c88c0a1a97f470090fe20,
the lttng_logger event was not working on signed kernels with non-signed
lttng modules.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add cscope to gitignore

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update kvm instrumentation: compile on 3.17-rc1

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update statedump to 3.17 nsproxy locking

This Linux upstream commit introduces locking strategy back and forth:

commit 728dba3a39c66b3d8ac889ddbe38b5b1c264aec3
Author: Eric W. Biederman <ebiederm@xmission.com>
Date:   Mon Feb 3 19:13:49 2014 -0800

    namespaces: Use task_lock and not rcu to protect nsproxy

Use the task lock starting from kernel 3.17 rather than RCU to access
the task nsproxy.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: noargs probes should calculate alignment and event length

A noargs probe could have event fields. noargs just means that the probe
does not receive any argument as parameter. However, it could very well
serialize data into fields (global variables, constants, etc).

It just happens that LTTng does not serialize any data in noargs events
at the moment, but this may very well change.

The if (0) with (void) variable access strategy to stop compiler from
complaining from unused variables does not seem to work as expected with
gcc 4.9.1. Use "unused" attribute instead.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update compaction instrumentation to 3.16 kernel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update vmscan instrumentation to 3.16 kernel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.5.0

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.5.0-rc2

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: statedump: check whether "files" is NULL, RCU semantic fix

We need to check if p->files is NULL before passing it to
files_fdtable(). Moreover, since the fdt is now protected by RCU, we
have to assume it can change between the read from
lttng_enumerate_task_fd() and the internal in-kernel read in
iterate_fd(). Therefore, move this rcu dereference into
lttng_dump_one_fd(), and perform the appropriate checks on max fds.

Fixes #799

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: statedump handle oom case, handle errors

lttng_enumerate_file_descriptors should check the pointer returned by
__get_free_page() (check if NULL).

do_lttng_statedump should check the sub-function return values. For
lttng_enumerate_block_devices(), we allow -ENOSYS to continue (if not
implemented).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: correct typo in kernel version number

A typo in a preprocessor conditional verifying the range in which the
current kernel version is situated caused build failure for modules on
3.5.0 specifically, by trying to use the new api for block_rq_complete
which has not been backported from the 3.15 branch to the 3.5 branch.

Signed-off-by: Antoine Busque <antoine.busque@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: blktrace instrumentation for backported branches

The following commit from kernel 3.15 changing the API of a block layer
tracepoint has been backported to multiple branches:

commit af5040da01ef980670b3741b3e10733ee3e33566
Author: Roman Pen <r.peniaev@gmail.com>
Date:   Tue Mar 4 23:13:10 2014 +0900

    blktrace: fix accounting of partially completed requests

This patch fixes the resulting build failure by adding the proper
version checks. The versions and corresponding commit SHA-1 hashes are
as follow:

   3.2.58
       commit 5b85afa68e4f56c27f1d5c6f49e5257bce6448e6

   3.4.91
       commit 14eee5bd065d6aac0acbdc6092a25ba68c55b9c8

   3.10.41
       commit e9d933941569c107e0083c3c115467c699a57db2

   3.12.21
       commit 5104b40a981d26212ced149fbd43ad0b6b72910b

   3.14.15
       commit 0a8eda9c00ef37e8b40de77f2b0714317191bcf2

Signed-off-by: Antoine Busque <antoine.busque@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: statedump block devices OOPS

Fixes #799

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.5.0-rc1

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add TID field to some block_* events

Most of the block events have the "comm" field, but we have no way to
match a block event to a certain thread which makes performing
accurate per-thread analyses difficult. Add the TID field to the events
that already export current->comm.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: refuse overwrite mode buffers with less than two subbuffers

Fixes #793

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: lttng modules system call generation script

Fixes #771

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Dump FD flags and mode on state dump

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: incorrect rwbs field type in block_bio_queue

Within lttng-modules instrumentation starting from kernel 3.9.0, the
block_bio_queue instrumentation has incorrect rwbs field type, and does
not print "comm" as an array of text.

The result is that we are writing values to what we believe to be an
"unsigned int", which is actually described as an array of RWBS_LEN byte
(8 bytes). This discrepancy between type description and the actual
tp_assign() incrementing the write offset leads to what appears as
corruption of the following "comm" field in the trace viewer output: the
viewer will skip the first bytes of the "comm" field, erroneously
thinking they belong the the previous "rwbs" field.

Fixes #794

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: blktrace instrumentation for v3.2.58+ stable branch

Starting with Linux kernel v3.2.58 within the v3.2 Linux stable branch:

commit 5b85afa68e4f56c27f1d5c6f49e5257bce6448e6
Author: Roman Pen <r.peniaev@gmail.com>
Date:   Tue Mar 4 23:13:10 2014 +0900

    blktrace: fix accounting of partially completed requests

    commit af5040da01ef980670b3741b3e10733ee3e33566 upstream.

The module API for a block layer tracepoint changes. Fix the associated
build failure.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: pass proper args when writing commit counter

lib_ring_buffer_write_commit_counter()'s 'buf_offset' argument should
contain offset of beginning of area used by the record being comitted.

However, lib_ring_buffer_commit() passes ctx->buf_offset, that gets
advanced by lib_ring_buffer_write() and thus points to just-after-
end-of-record at lib_ring_buffer_commit() time. This causes
lib_ring_buffer_write_commit_counter() to return without changing
commit_hot[idx].seq, due to

if (unlikely(subbuf_offset(offset - commit_count, chan)))
return;

Since after-crash data extraction tool checks 'seq' field to find out
how much data is in buffer, this results into inavailability of
data from partially-filled subbuffer for after-crash analysis.

This patch modifies lib_ring_buffer_write_commit_counter() and all its
callers to pass and expect the end of the area. So code works as it
should, and complete information becomes visible in crash dump.

[ Changelog inspired from Nikita Yushchenko's original patch. ]

Fixes #784

Reported-by: Nikita Yushchenko <nyoushchenko@mvista.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: lib ringbuffer: pagecpy has unsigned semantic

Same for lib_ring_buffer_read() orig_len.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: allow racy tracepoint string input from kernel and userspace

Fixes #781

Acked-by: David Goulet <dgoulet@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Statedump event for block devices

Signed-off-by: Houssem Daoud <houssemmh@gmail.com>
[ Edited by Mathieu Desnoyers. ]
Tested-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update v4l2 instrumentation to 3.15 kernel

show_type() is only used in TP_printk(), which is not used by LTTng
modules. Moreover, it is already defined by the in-kernel
instrumentation. Therefore, we can remove it from the lttng
instrumentation.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: ext4 update instrumentation to 3.15 kernel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update block instrumentation to 3.15 kernel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: module instrumentation: update to 3.15 kernel

Remove show_module_flags() define from lttng module.h instrumentation.
It is already defined within the in-kernel module.h, _and_ LTTng does
not use TP_printk.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Adapt to 3.15 tracepoint API

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Kernel 3.15 don't define map unmap for pipe

struct pipe_buf_operations does not have map and unmap fields starting
from kernel 3.15.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: add missing module version in v4l2 probe

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add V4L2 instrumentation

Add instrumentation for the V4L2 tracepoints that first appeared in
Linux v3.14 (commit 2d01237389dc64b37745ce87e64d6808b6eed582 in Linus's
tree).

Signed-off-by: Wade Farnsworth <wade_farnsworth@mentor.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: rcu instrumentation: add const qualifier to char pointers

Follow this 3.12 instrumentation update in mainline Linux:

commit e66c33d579ea566d10e8c8695a7168aae3e02992
Author: Steven Rostedt (Red Hat) <rostedt@goodmis.org>
Date:   Fri Jul 12 16:50:28 2013 -0400

    rcu: Add const annotation to char * for RCU tracepoints and functions

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: add missing module version information

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use kernel 3.13 syscall tables for MIPS32

Signed-off-by: Lars Persson <larper@axis.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add MIPS32 syscalls extracted from a 3.13 kernel

Signed-off-by: Lars Persson <larper@axis.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: block instrumentation: < 3.14 don't have bi_iter

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update btrfs instrumentation to kernel 3.14

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update block layer instrumentation to kernel 3.14

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: remove __exit annotation

lttng_abi_exit() is now used by init error path too.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix file permissions for lttng-statedump-impl.c

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

LTTng logger ABI

Add a user-space ABI (new file /proc/lttng-logger) to lttng-modules
which can be written into by any user on the system. The content is
saved into the kernel trace stream into the "lttng_logger" kernel event.

The content of a single write is written into an lttng_logger event.
The write count is truncated to 1024 bytes (if larger), which is much
smaller than the smallest subbuffer size available (4096 bytes). This
ensures all written data makes it into the active tracing buffers.

Example use:

lttng-sessiond -d # (as root)
lttng create
lttng enable-event -k lttng_logger
lttng start

echo -n "this is a test" > /proc/lttng-logger

lttng stop
lttng view

Example result:

[17:00:04.251970425] (+179.750663203) thinkos lttng_logger: { cpu_id = 3 }, { _msg_length = 14, msg = "this is a test" }

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Karim Yaghmour <karim.yaghmour@opersys.com>

Version 2.4.0

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: load state dump even if work-around lookup fails

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: fix comment

Fixes #652

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: correctly version kvm events to build against v3.0 kernel

Cleanly build against v3.0 kernel.  I didn't add versioning for mainline commit 0d460ffc as it's build compatible.

Signed-off-by: Tony Jones <tonyj@suse.de>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add extraversion (e.g. -rc4) to lttng-tracer modinfo

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.4.0-rc4

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: use after free in ring buffer clients

Don't use ring buffer client's struct lttng_channel from ioctl which
applies to ring buffer streams, because lttng_channel is freed while lib
ring buffer stream and channel are still in use. Their lifetime persists
until the consumer daemon releases its handles on the related stream
file descriptors.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Add statedump exit so module is not permanent

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: move callback init to static initialization

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: OOT lttng-statedump tracepoints not visible with signed kernels

Users have reported being unable to trace non-signed modules loaded
within a kernel supporting module signature.

Here is the relevant report of this issue to Linux upstream, with a
proposed fix: https://lkml.org/lkml/2014/2/10/747

Work-around the issue for lttng-statedump.ko tracepoints.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.4.0-rc3

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: tracepoint event name mapping at unregister

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: tracepoint name remapping

Commit

  "Introduce API to remap event names exposed by LTTng"

failed to map the event names enabled by the user to tracepoint names
known to the kernel. For instance, tracing with the kmem_kmalloc event
enabled is not gathering any event. This issue applies to all tracepoint
events declared with a different name within LTTng than within the Linux
kernel.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: enable event error path memory corruption

The call to

  kmem_cache_free(event_cache, event);

after setting event to ERR_PTR() value is causing memory corruption
(kernel oops). This bug has been introduced very recently by commit:

  Fix: provide more precise error report for enable event

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update kvm instrumentation to Linux 3.13

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update sched instrumentation to Linux 3.13

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: provide more precise error report for enable event

Fixes #658

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: quote event name in metadata

Allows adding events with a "-" within the name with --probe or
--function.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add version info to lttng-tracer.ko modinfo

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.4.0-rc2

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: client_packet_header() uses wrong packet

It should use lib_ring_buffer_read_offset_address() to get the packet
being read, rather than lib_ring_buffer_offset_address(), which is only
meant to be used when writing to the packet.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: fix typo in ring buffer backend comment

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: handle unknown event type parameter

Skip to an error path if the event type is unknown.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: eliminate timestamp overlap between packets

By using the timestamp sampled at space reservation when the packet is
being filled as "end timestamp" for a packet, we can ensure there is no
overlap between packet timestamp ranges, so that packet timestamp end <=
following packets timestamp begin.

Overlap between consecutive packets becomes an issue when the end
timestamp of a packet is greater than the end timestamp of a following
packet, IOW a packet completely contains the timestamp range of a
following packet.  This kind of situation does not allow trace viewers
to do binary search within the packet timestamps. This kind of situation
will typically never occur if packets are significantly larger than
event size, but this fix ensures it can never even theoretically happen.

The only case where packets can still theoretically overlap is if they
have equal begin and end timestamps, which is valid.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

gcc blacklist: only apply when building with gcc

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Blacklist ARM gcc 4.8.0, 4.8.1, 4.8.2

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.4.0-rc1

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update ext4 instrumentation to Linux 3.12

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update RCU instrumentation to Linux 3.12

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update btrfs instrumentation to 3.12 kernel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update vmscan instrumentation to Linux 3.12

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

update: kmem instrumentation 3.12 kernel support

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

lttng-statedump-impl: Use generic hard irqs for Linux >= 3.12

Quoting the original patch changelog from Otavio Salvador:

> The Linux kernel 3.12 uses the generic hard irqs system for all
> architectures and dropped the GENERIC_HARDIRQ option, as can be seen
> at the commit quoted below:
>
> ,----
> | commit 0244ad004a54e39308d495fee0a2e637f8b5c317
> | Author: Martin Schwidefsky <schwidefsky@de.ibm.com>
> | Date:   Fri Aug 30 09:39:53 2013 +0200
> |
> |     Remove GENERIC_HARDIRQ config option
> |
> |     After the last architecture switched to generic hard irqs the config
> |     options HAVE_GENERIC_HARDIRQS & GENERIC_HARDIRQS and the related code
> |     for !CONFIG_GENERIC_HARDIRQS can be removed.
> |
> |     Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
> `----

Introduce wrapper/irq.h to move the feature availability testing logic
into a specific wrapper header. It now tests if the kernel version is
>= 3.12 or if CONFIG_GENERIC_HARDIRQS is defined (for older kernels).
Introduce the lttng-specific CONFIG_LTTNG_HAS_LIST_IRQ to track
availability of this feature within LTTng.

Reported-by: Philippe Mangaud <r49081@freescale.com>
Reported-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

lttng-statedump-impl: Fix lttng_list_interrupts for empty implementation

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Import fix from LTSI: 3.4+ RT kernels use CONFIG_PREEMPT_RT_FULL

Initial LTSI commit:

From: Paul Gortmaker <paul.gortmaker@windriver.com>
> fix reference to obsolete RT Kconfig variable.
>
> The preempt-rt patches no longer use CONFIG_PREEMPT_RT in
> the 3.4 (and newer) versions.  So even though LTSI doesn't
> include RT, having this define present can lead to an easy
> to overlook bug for anyone who does try to layer RT onto
> the LTSI baseline.
>
> Update it to use the currently used define name by RT.
>
> Reported-by: Jim Somerville <Jim.Somerville@windriver.com>
> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

Merged with kernel version checks for >= 3.4 to support both old and
newer kernels.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add new tracepoint in KVM

New tracepoint added in kvm: kvm_write_tsc_offset.

Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Blacklist kernels 3.10.13 and 3.11.2

It looks like my guessing on kernel version at which Greg will pull this
fix was wrong. It will probably appear in the next round of stable
releases.

The fix that needs to reach stable-3.10 and stable-3.11 before we can
remove those from the backlist:

commit 7bd36014460f793c19e7d6c94dab67b0afcfcb7f
Author: John Stultz <john.stultz@linaro.org>
Date:   Wed Sep 11 16:50:56 2013 -0700

    timekeeping: Fix HRTICK related deadlock from ntp lock changes

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: John Stultz <john.stultz@linaro.org>

LTTng trace-clock: shrink kernel blacklist

The lockup fix has been pulled into Linux master as:

commit 7bd36014460f793c19e7d6c94dab67b0afcfcb7f
Author: John Stultz <john.stultz@linaro.org>
Date:   Wed Sep 11 16:50:56 2013 -0700

    timekeeping: Fix HRTICK related deadlock from ntp lock changes

Guessing the stable kernel versions in which this fix will appear in
3.10 and 3.11 stable. 3.12+ are OK.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: John Stultz <john.stultz@linaro.org>

Metadata flush writes data from the cache

When doing a flush on a metadata stream we first check if we can fill
the current subbuffer with data from the cache before doing the actual
flush.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Per-stream ioctl to get the current timestamp

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

LTTng ringbuffer ABI calls for index generation

These new calls export the data required for the consumer to generate
the index while tracing :
- timestamp begin
- timestamp end
- events discarded
- context size
- packet size
- stream id

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Prepare LTTng override of ring buffer fops

This patch allows LTTng to override the file operations of the lib ring
buffer.
For now it does not provide any additional functions, but it prepares
the work of adding LTTng-specific ioctls to the ring buffer.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Blacklist Linux kernels 3.10+

Linux kernels 3.10 and 3.11 introduce a deadlock in the timekeeping
subsystem. See
http://lkml.kernel.org/r/1378943457-27314-1-git-send-email-john.stultz@linaro.org
for details. Awaiting patch merge into Linux master, stable-3.10 and
stable-3.11 for fine-grained kernel version blacklisting.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.3.0

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: metadata stream should not reference session

The metadata stream should only reference the metadata cache, not the
session. Otherwise, we end up in a catch 22 situation:

- Stream POLLHUP is only given when the session is destroyed, but,
- The session is only destroyed when all references to session are
  released, including references from channels, but,
- If the metadata stream holds a reference on the metadata session, we
  end up with a circular dependency loop.

Fix this by making sure the metadata stream does not use any of the
lttng channel nor lttng session.

Reviewed-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: btrfs: support 3.11 Linux kernel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

statedump: remove KERN_DEBUG messages

They appear to be shown by default in dmesg of many distributions, and
they don't add much value (noisy).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: ext4: add missing tracepoints for 3.11 kernel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: ext4: Linux 3.11 support

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: ext3: 3.11 Linux support

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: statedump nsproxy 3.11 Linux support

Follow upstream Linux change introduced by:

commit c2b1df2eb42978073ec27c99cc199d20ae48b849
Author: Andy Lutomirski <luto@amacapital.net>
Date:   Thu Aug 22 11:39:16 2013 -0700

    Rename nsproxy.pid_ns to nsproxy.pid_ns_for_children

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.3.0-rc2

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: metadata lttng channel refcount

The OOPS at bug #622 is likely caused by a missing reference on the
lttng channel structure, which could lead to accessing the object after
it has been destroyed if the lttng channel file descriptor is closed
while the metadata stream fd is still in use.

Fixes #622

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Julien Desfossez <jdesfossez@efficios.com>

README: lttng-modules incompatible with lttng 0.x patchset

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.3.0-rc1

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>