Change-Id: Ia84cc24c8924e6d22d02ac15f611c10e26db99b4
Signed-off-by: Nigel Babu <nigelb@redhat.com>

see https://review.gluster.org/#/c/19788/,
    https://review.gluster.org/#/c/19871/,
    https://review.gluster.org/#/c/19952/,
    https://review.gluster.org/#/c/20104/,
    https://review.gluster.org/#/c/20162/,
    https://review.gluster.org/#/c/20185/,
    https://review.gluster.org/#/c/20207/,
    https://review.gluster.org/#/c/20227/,
    https://review.gluster.org/#/c/20307/,
    https://review.gluster.org/#/c/20320/,
    https://review.gluster.org/#/c/20332/,
    https://review.gluster.org/#/c/20364/,
    https://review.gluster.org/#/c/20441/, and
    https://review.gluster.org/#/c/20484

shebangs changed from /usr/bin/python2 to /usr/bin/python3.
(Reminder, various distribution packaging guidelines require use
of explicit python version and don't allow '#!/usr/bin/env python',
regardless of how handy that idiom may be.)

glusterfs.spec(.in) package python{2,3}-gluster and python2 or
python3 dependencies as appropriate.

configure(.ac):
+ test for and use python2 or python3 as appropriate. If build
  machine has python2 and python3, use python3. Override by
  setting PYTHON=/usr/bin/python2 when running configure.
+ PYTHONDEV_CPPFLAGS from python[23]-config --includes is a
  better match to the original python sysconfig.get_python_inc().
  All those other extraneous flags breaks the build.
+ Only change the shebangs once. Changing them over and over
  again, e.g., during a `make glusterrpms` in extras/LinuxRPM
  just sends make (is it really make that's looping?) into an
  infinite loop. If you figure out why, let me know.
+ Oldest python2 is python2.6 on CentOS 6 and Debian 8 (Jessie).
  Everything else has 2.7 or 3.x
+ logic from https://review.gluster.org/c/glusterfs/+/21050, which
  needs to be removed/merged after that patch is merged.

Builds on CentOS 6, CentOS 7, Fedora 28, Fedora rawhide, and the
mysterious RHEL > 7.

Change-Id: Idae21d3b6f58b32372e1daa0d234e491e563198f
updates: #411
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>

see https://review.gluster.org/#/c/19788/

use print fn from __future__

Change-Id: If5075d8d9ca9641058fbc71df8a52aa35804cda4
updates: #411
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>

Note 1) we're not supposed to be using #!/usr/bin/env python, see
https://fedoraproject.org/wiki/Packaging:Guidelines?rd=Packaging/Guidelines#Shebang_lines

Note 2) we're also not supposed to be using "!/usr/bin/python,
see https://fedoraproject.org/wiki/Changes/Avoid_usr_bin_python_in_RPM_Build#Quick_Opt-Out

The previous patch (https://review.gluster.org/19767) tried to do too
much in one patch, so it was abandoned.

This patch does two things:
1) minor cleanup of configure(.ac) to explicitly use python2
2) change all the shebang lines to #!/usr/bin/python2 and add them
where they were missing based on warnings emitted during rpmbuild.

In a follow-up patch python2 will eventually be changed to python3.

Before that python2-isms (e.g. print, string.join(), etc.) need to be
converted to python3. Some of those can be rewritten in version agnostic
python. E.g. print statements become print() with "from __future_ import
print_function". The python 2to3 utility will be used for some of those.
Also Aravinda has given guidance in the comments to the first patch for
changes.

updates: #411
Change-Id: I471730962b2526022115a1fc33629fb078b74338
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>

`find_library()` doesn't consider LD_LIBRARY_PATH on Python < 3.6.

Change-Id: Iee26085cb5d14061001f19f032c2664d69a378a8
BUG: 1450593
Signed-off-by: Niklas Hambüchen <mail@nh2.me>

Incorporate the new API 'gf_changelog_init'
introduced in libgfchangelog which should
be called before 'gf_changelog_register'.

Change-Id: I10a9dd5ff3ecc64fd61dcb6b1aa53739e0bdeedd
BUG: 1238063
Signed-off-by: Kotresh HR <khiremat@redhat.com>
Reviewed-on: http://review.gluster.org/11479
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Venky Shankar <vshankar@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

[WIP patch as of now, just needs a little tweak]

A pending TODO in the code caused regressions to fail as
bitrot daemons are spawned during volume start (equivalent
to enabling bitrot by default). The problematic part that
casued such failures is during brick disconnections with
unsafe handling of event data structured in the code.

With this patch, data structures are properly cleaned up
with care taken to cleanup all accessors first. This also
fixes potential memory leaks which was bluntly ignored
before.

Change-Id: I70ed82cb1a0fb56c85ef390007e321a97a35c5ce
BUG: 1170075
Signed-off-by: Venky Shankar <vshankar@redhat.com>
original-author: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/9959
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Tested-by: Vijay Bellur <vbellur@redhat.com>

Problem:
libgfchangelog initializes global xlator on library load (via
constructor: _ctor) and mangles it's xlator context thereby
messing with certain important members of the command structure.
On receiving an RPC disconnection event, if the point-of-execution
was in libgfchangelogs context, accessing ->cmd_args during RPC
notify resulted in a segfault.

Fix:
Since the libarary needs to be able to work with processes that
have a notion of an xlator (THIS in particular) and without it,
care needs to be taken to allocate the global xlator when needed.
Moreover, the actual fix is to use the correct xlator context
in both cases. A new API is introduces when needs to be invoked
by the conusmer (although this could have been done during
register() call, keeping it a separate API makes thing flexible
and easy).

Test:
The issue is observed when a brick process goes offline. This is
triggered when test cases (.t's) are run in bulk, since each
test essestially spawns bricks processes (on volume start) and
terminates them (volume stop). Since bitrot daemon, as of now,
spawns upon volume start, the issue is much observed when the
volume is taken offline at the end of each test case. With this
fix, running the basic and core test cases along with building
the linux kernel has passed without daemon segfaults.

Thanks to Johnny (rabhat@) for helping in debugging the issue
(and with the fix :)).

Change-Id: I8d3022bf749590b2ee816504ed9b1dfccc65559a
BUG: 1170075
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/9953
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Tested-by: Vijay Bellur <vbellur@redhat.com>

This patch introduces RPC based communication between the changelog
translator and libgfchangelog. It replaces the old pathetic stream
based interaction that existed earlier (due to time constraints :-/).

Changelog, upon initialization starts a RPC server (rpcsvc) allowing
clients to invoke a probe API as a bootup mechanism to request for
event notifications. During probe, clients can choose an event
filter specifying the type(s) of events they are interested in. As
of now there is no way to change the event notification set once
the probe RPC call is made, but that is easier to implement.

The actual event notifications is done on a separate RPC session.
The client (libgfchangelog) itself starts and RPC server which the
changelog translator "connects back" during probe. Notifications
are dispatched by a bunch of threads from the server (translator)
and the client optionally orders them if ordered notifications
are requried. FOPs fill in their respective event details in a
buffer (rot-buffs to be particular) and a bunch of threads
(consumers) swap the buffers out of roatation and dispatch them
via RPC. To avoid writer starvation, then number of dispatcher
threads is one less than the number of buffer list in rot-buffs.x

libgfchangelog becomes purely callback based -- upon event
notification from the server (and re-ordering them if required)
invoke a callback routine specified by consumer(s).

A major part of the patch is also aimed at providing backward
compatibility for geo-replication, which was one of the main
consumer of the stream based API. Also, this patch does not\
"turn on" event notifications for all fops, just a bunch which
is currently in requirement. Another pain point is that the
server does not filter events before dispatching it to the
clients. That load is taken up by the client itself (although
it's done at the library layer rather than making it hard on
the callback implementor). This needs improvement and care
needs to be taken to not load the server up with expensive
filtering mechanisms.

Change-Id: Ibf60a432b68f2dfa60c6f9add2bcfd37a9c41395
BUG: 1170075
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/9708
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

Facilitates Glusterfs with the ability to detect file-operations
happened in past by scanning the back-end(brick-level) glusterfs
journal (changelog).

Design:
  * List of changelogs produces in one perfectly running session are
    stored in htime file which also holds necessary information about
    the session start and end time.
  * Involves fixed sized seeks to identify N'th changelog in the list.
  * Requires O(log n), (where n is number of changelogs in the list),
    time to identify the end changelog for the given start-end time
    interval.

Currently the background processing of changelogs is sub optimal. BZ
1097041 tracks the development effort.

For complete design, refer the below link:
http://lists.nongnu.org/archive/html/gluster-devel/2014-02/msg00206.html

Change-Id: I27e49f75e492e843084d0ecaf9130224d08462a0
BUG: 1091961
Signed-off-by: Ajeet Jha <ajha@redhat.com>
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Signed-off-by: Ajeet Jha <ajha@redhat.com>
Reviewed-on: http://review.gluster.org/6930
Reviewed-by: Kotresh HR <khiremat@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>