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>

1 files changed, 3 insertions, 0 deletions

diff --git a/glusterfsd/src/glusterfsd-mgmt.c b/glusterfsd/src/glusterfsd-mgmt.c
index f1b2f9e7123..1e9015440ae 100644
--- a/glusterfsd/src/glusterfsd-mgmt.c
+++ b/glusterfsd/src/glusterfsd-mgmt.c
@@ -919,6 +919,9 @@ glusterfs_handle_attach (rpcsvc_request_t *req)
                                 "got attach for %s but no active graph",
                                 xlator_req.name);
                 }
+                if (ret) {
+                        ret = -1;
+                }
 
                 glusterfs_translator_info_response_send (req, ret, NULL, NULL);