PROBLEM
--------

statedump requests that traverse call frames of all call stacks in
execution may race with a STACK_RESET on a stack.  This could crash the
corresponding glusterfs process. For e.g, recently we observed this in a
regression test case tests/basic/afr/sparse-self-heal.t.

FIX
---

gf_proc_dump_pending_frames takes a (TRY_LOCK) call_pool->lock before
iterating through call frames of all call stacks in progress.  With this
fix, STACK_RESET removes its call frames under the same lock.

Additional info
----------------

This fix makes call_stack_t to use struct list_head in place of custom
doubly-linked list implementation. This makes call_frame_t manipulation
easier to maintain in the context of STACK_WIND et al.

BUG: 1234408
Change-Id: I7e43bccd3994cd9184ab982dba3dbc10618f0d94
Signed-off-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-on: http://review.gluster.org/11095
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
(cherry picked from commit 79e4c7b2fad6db15863efb4e979525b1bd4862ea)
Reviewed-on: http://review.gluster.org/11352

- Follow formatting rules based on RFC4627 -
  http://www.ietf.org/rfc/rfc4627.txt
- Add checks for json in regression test meta.t

Change-Id: I480d32ce042b202d3ed8939623c629a03b458551
BUG: 1089216
Signed-off-by: Harshavardhana <harsha@harshavardhana.net>
Reviewed-on: http://review.gluster.org/7653
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

Various parts of process state dump are exposed
through most appropriate virual files/dirs

Change-Id: Iff30f8ea76552f2f6d9c98def688c5ec4bc6f2af
BUG: 1089216
Signed-off-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.org/7542
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Harshavardhana <harsha@harshavardhana.net>