* libglusterfs changes to add new fop

    * Fuse changes:
      - Changes in fuse bridge xlator to receive and send responses

    * posix changes to perform the op on the backend filesystem

    * protocol and rpc changes for sending and receiving the fop

    * gfapi changes for performing the fop

    * tools: glfs-copy-file-range tool for testing copy_file_range fop

      - Although, copy_file_range support has been added to the upstream
	    fuse kernel module, no release has been made yet of a kernel
        which contains the support. It is expected to come in the
        upcoming release of linux-4.20

        So, as of now, executing copy_file_range fop on a fused based
        filesystem results in fuse kernel module sending read on the
	    source fd and write on the destination fd.

	    Therefore a small gfapi based tool has been written to be able
        test the copy_file_range fop. This tool is similar (in functionality)
	    to the example program given in copy_file_range man page.

	    So, running regular copy_file_range on a fuse mount point and
	    running gfapi based glfs-copy-file-range tool gives some idea about
	    how fast, the copy_file_range (or reflink) can be.

	    On the local machine this was the result obtained.

	    mount -t glusterfs workstation:new /mnt/glusterfs
	    [root@workstation ~]# cd /mnt/glusterfs/
	    [root@workstation glusterfs]# ls
	    file
	    [root@workstation glusterfs]# cd
	    [root@workstation ~]# time /tmp/a.out /mnt/glusterfs/file /mnt/glusterfs/new
	    real  0m6.495s
	    user  0m0.000s
	    sys   0m1.439s
	    [root@workstation ~]# time glfs-copy-file-range $(hostname) new /tmp/glfs.log /file /rrr
	    OPEN_SRC: opening /file is success
	    OPEN_DST: opening /rrr is success
	    FSTAT_SRC: fstat on /rrr is success
	    copy_file_range successful

        real  0m0.309s
        user  0m0.039s
        sys   0m0.017s

        This tool needs following arguments
         1) hostname
         2) volume name
         3) log file path
         4) source file path (relative to the gluster volume root)
         5) destination file path (relative to the gluster volume root)

        "glfs-copy-file-range <hostname> <volume> <log file path> <source> <destination>"

      - Added a testcase as well to run glfs-copy-file-range tool

    * io-stats changes to capture the fop for profiling

    * NOTE:

      - Added conditional check to see whether the copy_file_range syscall
        is available or not. If not, then return ENOSYS.

      - Added conditional check for kernel minor version in fuse_kernel.h
        and fuse-bridge while referring to copy_file_range. And the kernel
        minor version is kept as it is. i.e. 24. Increment it in future
        when there is a kernel release which contains the support for
        copy_file_range fop in fuse kernel module.

    * The document which contains a writeup on this enhancement can be found at
      https://docs.google.com/document/d/1BSILbXr_knynNwxSyyu503JoTz5QFM_4suNIh2WwrSc/edit

Change-Id: I280069c814dd21ce6ec3be00a884fc24ab692367
updates: #536
Signed-off-by: Raghavendra Bhat <raghavendra@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/,
    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/, and
    https://review.gluster.org/#/c/20364/

Fixes glupy.py python2isms, iteritems -> items, and some overlooked 
print() in georep/peer_mountbroker.in

Note: Fedora packaging guidelines and SUSE rpmlint require explicit
shebangs; popular practices like #!/usr/bin/env python and #!/usr/bin/python
are not allowed; they must be #!/usr/bin/python2 or #!/usr/bin/python3

Note: Selected small fixes from 2to3 utility. Specifically apply,
basestring, funcattrs, has_key, idioms, map, numliterals, raise,
set_literal, types, urllib, and zip have already been applied. Also
version agnostic imports for urllib, cpickle, socketserver, _thread,
queue, etc., suggested by Aravinda in https://review.gluster.org/#/c/19767/1

Note: these 2to3 fixes report no changes are necessary: asserts, buffer,
exec, execfile, exitfunc, filter, getcwdu, imports2, input, intern,
itertools, metaclass, methodattrs, ne, next, nonzero, operator, paren,
raw_input, reduce, reload, renames, repr, standarderror, sys_exc, throw,
tuple_params, xreadlines.

Change-Id: Idda031c1ec975417c79323aea33e7b694e752b2a
updates: #411
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@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/, and
    https://review.gluster.org/#/c/20332/

This patch fixes the remaining comma white space (ws_comma) as suggested
by the 2to3 utility. (Earlier attempts to fix all ws_comma in one
patch did not pass centos regression, hence multiple patches to identify
the change that causes the failure.)

Note: Fedora packaging guidelines and SUSE rpmlint require explicit
shebangs; popular practices like #!/usr/bin/env python and #!/usr/bin/python
are not allowed; they must be #!/usr/bin/python2 or #!/usr/bin/python3

Note: Selected small fixes from 2to3 utility. Specifically apply,
basestring, funcattrs, has_key, idioms, map, numliterals, raise,
set_literal, types, urllib, and zip have already been applied. Also
version agnostic imports for urllib, cpickle, socketserver, _thread,
queue, etc., suggested by Aravinda in https://review.gluster.org/#/c/19767/1

Note: these 2to3 fixes report no changes are necessary: asserts, buffer,
exec, execfile, exitfunc, filter, getcwdu, imports2, input, intern,
itertools, metaclass, methodattrs, ne, next, nonzero, operator, paren,
raw_input, reduce, reload, renames, repr, standarderror, sys_exc, throw,
tuple_params, xreadlines.

Change-Id: If5aca67084a7b1c06966fed35fb35e8bb2f7d67c
updates: #411
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>

see https://review.gluster.org/#/c/19788/,
    https://review.gluster.org/#/c/19871/,
    https://review.gluster.org/#/c/19952/, and
    https://review.gluster.org/#/c/20104/
    https://review.gluster.org/#/c/20162/

This patch changes uses of map() and raise(), and a few cases of print()
that were overlooked in the prior patch that fixed print.

Note: Fedora packaging guidelines require explicit shebangs, so popular
practices like #!/usr/bin/env python and #!/usr/bin/python are not
allowed; they must be #!/usr/bin/python2 or #!/usr/bin/python3

Note: Selected small fixes from 2to3 utility. Specifically apply,
basestring, funcattrs, idioms, numliterals, set_literal, types, urllib,
zip, map, and raise have already been applied. Also version agnostic
imports for urllib, cpickle, socketserver, _thread, queue, etc., suggested
 by Aravinda in https://review.gluster.org/#/c/19767/1

Note: these 2to3 fixes report no changes are necessary: asserts, buffer,
exec, execfile, exitfunc, filter, getcwdu, intern, itertools, metaclass,
methodattrs, ne, next, nonzero, operator, paren, raw_input, reduce,
reload, renames, repr, standarderror, sys_exc, throw, tuple_params,
xreadlines.

Change-Id: Id62ea491e4ab5dd390075c5c6d9d889cf6f9da27
updates: #411
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>

see https://review.gluster.org/#/c/19788/ and
    https://review.gluster.org/#/c/19871/

Selected small fixes from 2to3 utility. Specifically apply, basestring,
funcattrs, idioms, numliterals, set_literal, types, urllib, zip

Note: these 2to3 fixes report no changes are necessary: exec, execfile,
exitfunc, filter, getcwdu, intern, itertools, metaclass, methodattrs, ne,
next, nonzero, operator, paren, raw_input, reduce, reload, renames, repr,
standarderror, sys_exc, throw, tuple_params, xreadlines.

Any 2to3 fixes not in the above two lists have more extensive changes
which will follow in separate patches.

most unicode changes suggested by 2to3 will need to be applied at the
same time as changing the shebangs from python2 to python3. Prashanth
notes that unicode strings in py2 need 'u' prefix; unicode strings in
py3 3.0, 3.1, and 3.2 a 'u' prefix will throw an error, but in py3 3.3+
it is legal (or just ignored). All Linux dists we care about have 3.3
or later so we can leave 'u' prefixes on unicode strings.

Change-Id: I49bba2f328b0ee24b9a8115a7183be979981563e
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>

spec-files:
https://review.gluster.org/#/c/18854/

Overview:
* Cloudsync maintains three file states in it's inode-ctx i.e
  1 - LOCAL,
  2 - REMOTE,
  3 - DOWNLOADING.

* A data modifying fop is allowed only if the state is LOCAL.
  If the state is REMOTE or DOWNLOADING, client will download
  or wait for the download to finish initiated by other client.

* Multiple download and upload from different clients are synchronized
  by inodelk.

* In POSIX a state check is done (part of different commit)before
  allowing the fop to continue. If the state is remote/downloading the
  fop is unwound with EREMOTE. The client will then download the file
  and continue with the fop again.

* Basic Algo for fop (let's say write fop):
  - If LOCAL -> resume fop
  - If REMOTE ->
	- INODELK
	- STAT (this gets state and heal the state if needed)
	- DOWNLOAD
	- resume fop

Note:
* Developers will need to write plugins for download, based on the
remote store they choose. In phase-1, support will be added for
one remote store per volume. In future, more options for multiple
remote stores will be explored.

TODOs:
 - Implement stat/lookup/readdirp to return size info from xattr
 - Make plugins configurable
 - Implement unlink fop
 - Add metrics collection
 - Add sharding support

Design Contributions:
Aravinda V K <avishwan@redhat.com>
Amar Tumballi <amarts@redhat.com>
Ram Ankireddypalle <areddy@commvault.com>
Susant Palai <spalai@redhat.com>

updates: #387
Change-Id: Iddf711ee7ab4e946ae3e472ff62791a7b85e6d4b
Signed-off-by: Susant Palai <spalai@redhat.com>

Updates: #389
Change-Id: I8faea0828921fb17f05f7321c3cb01747373f21e
Signed-off-by: Kinglong Mee <mijinlong@open-fs.com>

Updates: #389
Change-Id: I4153df72d5eeecefa7579170899db4c340128bea
Signed-off-by: Kinglong Mee <mijinlong@open-fs.com>