Introduce a `./configure --enable-asan` to build with
`-fsanitize=address -fno-omit-frame-pointer` options. This uses the
libasan.so shared library, so that needs to be available.

While running builds with the ASAN options, several linker issues
surfaced and these have been addressed with this change as well.
Building with --enable-asan has been tested on Fedora 28.

Change-Id: I428a9da70dd8f7d0056cfbe5c398619a571469b2
Updates: #492
Signed-off-by: Niels de Vos <ndevos@redhat.com>

This is a plugin which provides an interface to retrive files from amazon-s3
which are archived in to s3.

Users need to give the above information for cloudsync to retrieve the file
from s3.

TODO:
1- A separate commit in to developer-guide will detail about the usage
of this plugin in more detail.
2- Need to create target file in aws-bucket with "gfid" names. Helps avoiding
name collisions.

Change-Id: I2e4a586f4e3f86164de9178e37673a07f317e7d9
Updates: #387
Signed-off-by: Susant Palai <spalai@redhat.com>

CLOUDSYNC_SRC is defined twice in the same Makefile.am which generates
the following warning:

xlators/features/cloudsync/src/Makefile.am:9: warning: CLOUDSYNC_SRC multiply defined in condition TRUE ...
xlators/features/cloudsync/src/Makefile.am:5: ... 'CLOUDSYNC_SRC' previously defined here

Therefore removing the duplicate definition.

Change-Id: I00c3e2f3d64ad45e4080c2c82766516cd3e2bf63
fixes: bz#1193929
BUG: 1193929
Signed-off-by: Anoop C S <anoopcs@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>