- Added kernel-writeback-cache command line and xlator
  option for requesting utilisation of the writeback
  cache of the kernel in FUSE_INIT (see [1]).
- Added attr-times-granularity command line and xlator
  option via which granularity of the {a,m,c}time in
  stat (attr) data that we support can be indicated to
  kernel. This is a means to avoid divergence of the
  attr times between kernel and userspace that could
  occur with writeback-cache, while still maintaining
  maximum time precision the FUSE server is capable of
  (see [2]).
- Handling FATTR_CTIME flag in FUSE_SETATTR that
  indicates presence of ctime in setattr payload.
  Currently we cannot associate arbitrary ctimes to
  files on backend, so we just touch them to update
  their ctimes to current time. Having ctimes in setattr
  payload is also a side effect of writeback cache
  (see [3] and [4]).

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4d99ff8,
     "fuse: Turn writeback cache on"
[2]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e27c9d3,
     "fuse: fuse: add time_gran to INIT_OUT"
[3]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1e18bda,
     "fuse: add .write_inode"
[4]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ab9e13f,
     "fuse: allow ctime flushing to userspace"

Updates: #435
Change-Id: Id174c8e0c815c4456c35f8c53e41a6a507d91855
Signed-off-by: Csaba Henk <csaba@redhat.com>

Problem: glusterd2 build is failed due to undefined symbol
         (xlator_mem_cleanup , glusterfsd_ctx) in server.so

Solution: To resolve the same done below two changes
          1) Move xlator_mem_cleanup code from glusterfsd-mgmt.c
             to xlator.c to be part of libglusterfs.so
          2) replace glusterfsd_ctx to this->ctx because symbol
             glusterfsd_ctx is not part of server.so

BUG: 1544090
Change-Id: Ie5e6fba9ed458931d08eb0948d450aa962424ae5
fixes: bz#1544090
Signed-off-by: Mohit Agrawal <moagrawa@redhat.com>

Problem: Sometimes brick process is getting crashed at the time
         of stop brick while brick mux is enabled.

Solution: Brick process was getting crashed because of rpc connection
          was not cleaning properly while brick mux is enabled.In this patch
          after sending GF_EVENT_CLEANUP notification to xlator(server)
          waits for all rpc client connection destroy for specific xlator.Once rpc
          connections are destroyed in server_rpc_notify for all associated client
          for that brick then call xlator_mem_cleanup for for brick xlator as well as
          all child xlators.To avoid races at the time of cleanup introduce
          two new flags at each xlator cleanup_starting, call_cleanup.

BUG: 1544090
Signed-off-by: Mohit Agrawal <moagrawa@redhat.com>

Note: Run all test-cases in separate build (https://review.gluster.org/#/c/19700/)
      with same patch after enable brick mux forcefully, all test cases are
      passed.

Change-Id: Ic4ab9c128df282d146cf1135640281fcb31997bf
updates: bz#1544090

Problem:
The values for inode/fd was populated from the ctx received
from the server xlator.
Without brickmux, every brick from a volume belonged to a
single brick from the volume.
So searching the server and populating it worked.

With brickmux, a number of bricks can be confined to a single
process. These bricks can be from different volumes too (if
we use the max-bricks-per-process option).
If they are from different volumes, using the server xlator
to populate causes problem.

Fix:
Use the brick to validate and populate the inode/fd status.

Signed-off-by: hari gowtham <hgowtham@redhat.com>

Change-Id: I2543fa5397ea095f8338b518460037bba3dfdbfd
fixes: bz#1566067

xlator_notify doesn't pass the extra arguments that come in the
input function, so XLATOR_NOTIFY macro should be used instead
to pass the extra arguments to the function.

BUG: 1567881
fixes bz#1567881
Change-Id: Ic15b6c446638cbacf3149693147a754219037c47
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

  - Removed unused struct member and its one time usage.
  - cleaned up wrong white space

member 'client_latency' was not used otherwise since it was added by

commit 07cc8679cdf3b29680f4f105d0222da168d8bfc1
Author: Kevin Vigor <kvigor@fb.com>
Date:   Tue Mar 21 08:23:25 2017 -0700

    Halo Replication feature for AFR translator

Change-Id: Ibb0ea828d4090bbe8897f6af326b317884162a00
BUG: 1495153
Signed-off-by: Sven Fischer <sven@fischer-abc.de>

updates: #304

Change-Id: If6a13d2e56b195390a386d720103a882e077f66c
Signed-off-by: Amar Tumballi <amarts@redhat.com>

The volume_options_t struct was modified and a new member was introduced
in the middle of the struct. This caused GD2 to crash when it tried to
read the volume options. The new member has been moved to the end of the
struct to correct this.

And a note has been added to notify developers on how to modify this
struct, and the xlator_api_t struct.

Updates: gluster/glusterfs#302

Change-Id: I2e9899ec10516be29c7e9d574da53be8ec17a99e
Signed-off-by: Kaushal M <kaushal@redhat.com>

This helps external applications which wants to consume xlator_api
to read only fields (and not functions) using dlopen() to write
smaller structures/objects and still achieve their requirements.
One such example is GD2 project.

Updates #168

Change-Id: I8737939c8c72f6572ee1514201e9f9f8e4f37b40
Signed-off-by: Amar Tumballi <amarts@redhat.com>

* Introduce xlator methods to allow dumping of metrics
* Separate options to get the metrics dumped in a path

Updates #168

Change-Id: I7df80df33b71d6f449f03c2332665b4a45f6ddf2
Signed-off-by: Amar Tumballi <amarts@redhat.com>