glusterd: Add multiple checks before attach/start a brick

Problem: In brick mux scenario sometime glusterd is not able
         to start/attach a brick and gluster v status shows
         brick is already running

Solution:
          1) To make sure brick is running check brick_path in
             /proc/<pid>/fd , if a brick is consumed by the brick
             process it means brick stack is come up otherwise not
          2) Before start/attach a brick check if a brick is mounted
             or not
          3) At the time of printing volume status check brick is
             consumed by any brick process

Test:  To test the same followed procedure
       1) Setup brick mux environment on a vm
       2) Put a breaking point in gdb in function posix_health_check_thread_proc
          at the time of notify GF_EVENT_CHILD_DOWN event
       3) unmount anyone brick path forcefully
       4) check gluster v status it will show N/A for the brick
       5) Try to start volume with force option, glusterd throw
          message "No device available for mount brick"
       6) Mount the brick_root path
       7) Try to start volume with force option
       8) down brick is started successfully

Change-Id: I91898dad21d082ebddd12aa0d1f7f0ed012bdf69
fixes: bz#1595320
Signed-off-by: Mohit Agrawal <moagrawa@redhat.com>

0 files changed, 0 insertions, 0 deletions