core: Log level changes do not effect on running client process

Problem: commit c34e4161f3cb6539ec83a9020f3d27eb4759a975 set log-level
         per xlator during reconfigure only for a brick process not for
         the client process.

Solution: 1) Change per xlator log-level only if brick_mux is enabled.To make sure
             about brick multiplex introudce a flag brick_mux at ctx->cmd_args.

Note: There are two other changes done with this patch
      1) Ignore client-log-level option to attach a brick with
         already running brick if brick_mux is enabled
      2) Add a log to print pid of the running process to make easier
         debugging

> Change-Id: I39e85de778e150d0685cd9a79425ce8b4783f9c9
> Signed-off-by: Mohit Agrawal <moagrawal@redhat.com>
> Fixes: bz#1696046
> (Cherry picked from commit 798aadbe51a9a02dd98a0f861cc239ecf7c8ed57)
> (Reviewed on upstream link https://review.gluster.org/#/c/glusterfs/+/22495/)

Change-Id: If91682830f894ab8f6857f19dcb1797fc15ca64c
Fixes: bz#1699715
Signed-off-by: Mohit Agrawal <moagrawal@redhat.com>

3 files changed, 18 insertions, 3 deletions

diff --git a/glusterfsd/src/glusterfsd-messages.h b/glusterfsd/src/glusterfsd-messages.h
index 602cd9ecfd5..ce6c8ca56a5 100644
--- a/glusterfsd/src/glusterfsd-messages.h
+++ b/glusterfsd/src/glusterfsd-messages.h
@@ -35,6 +35,7 @@ GLFS_MSGID(GLUSTERFSD, glusterfsd_msg_1, glusterfsd_msg_2, glusterfsd_msg_3,
            glusterfsd_msg_28, glusterfsd_msg_29, glusterfsd_msg_30,
            glusterfsd_msg_31, glusterfsd_msg_32, glusterfsd_msg_33,
            glusterfsd_msg_34, glusterfsd_msg_35, glusterfsd_msg_36,
-           glusterfsd_msg_37, glusterfsd_msg_38, glusterfsd_msg_39);
+           glusterfsd_msg_37, glusterfsd_msg_38, glusterfsd_msg_39,
+           glusterfsd_msg_40);
 
 #endif /* !_GLUSTERFSD_MESSAGES_H_ */
diff --git a/glusterfsd/src/glusterfsd.c b/glusterfsd/src/glusterfsd.c
index 5d46b3d9f45..fc86cbdccc9 100644
--- a/glusterfsd/src/glusterfsd.c
+++ b/glusterfsd/src/glusterfsd.c
@@ -275,6 +275,7 @@ static struct argp_option gf_options[] = {
      "attribute, dentry and page-cache. "
      "Disable this only if same files/directories are not accessed across "
      "two different mounts concurrently [default: \"on\"]"},
+    {"brick-mux", ARGP_BRICK_MUX_KEY, 0, 0, "Enable brick mux. "},
     {0, 0, 0, 0, "Miscellaneous Options:"},
     {
         0,
@@ -711,7 +712,6 @@ create_fuse_mount(glusterfs_ctx_t *ctx)
     xlator_t *master = NULL;
 
     cmd_args = &ctx->cmd_args;
-
     if (!cmd_args->mount_point) {
         gf_msg_trace("glusterfsd", 0,
                      "mount point not found, not a client process");
@@ -1099,6 +1099,10 @@ parse_opts(int key, char *arg, struct argp_state *state)
             cmd_args->thin_client = _gf_true;
             break;
 
+        case ARGP_BRICK_MUX_KEY:
+            cmd_args->brick_mux = _gf_true;
+            break;
+
         case ARGP_PID_FILE_KEY:
             cmd_args->pid_file = gf_strdup(arg);
             break;
@@ -1216,7 +1220,6 @@ parse_opts(int key, char *arg, struct argp_state *state)
         case ARGP_KEY_ARG:
             if (state->arg_num >= 1)
                 argp_usage(state);
-
             cmd_args->mount_point = gf_strdup(arg);
             break;
 
@@ -2549,6 +2552,8 @@ postfork:
         if (ret)
             goto out;
     }
+    gf_log("glusterfs", GF_LOG_INFO, "Pid of current running process is %d",
+           getpid());
     ret = gf_log_inject_timer_event(ctx);
 
     glusterfs_signals_setup(ctx);
@@ -2814,6 +2819,14 @@ main(int argc, char *argv[])
     if (ret)
         goto out;
 
+    /* set brick_mux mode only for server process */
+    if ((ctx->process_mode != GF_SERVER_PROCESS) && cmd->brick_mux) {
+        gf_msg("glusterfs", GF_LOG_CRITICAL, 0, glusterfsd_msg_40,
+               "command line argument --brick-mux is valid only for brick "
+               "process");
+        goto out;
+    }
+
     /* log the version of glusterfs running here along with the actual
        command line options. */
     {
diff --git a/glusterfsd/src/glusterfsd.h b/glusterfsd/src/glusterfsd.h
index 35cf6d88b7a..fa55789c611 100644
--- a/glusterfsd/src/glusterfsd.h
+++ b/glusterfsd/src/glusterfsd.h
@@ -111,6 +111,7 @@ enum argp_option_keys {
     ARGP_FUSE_FLUSH_HANDLE_INTERRUPT_KEY = 189,
     ARGP_FUSE_LRU_LIMIT_KEY = 190,
     ARGP_FUSE_AUTO_INVAL_KEY = 191,
+    ARGP_BRICK_MUX_KEY = 192
 };
 
 struct _gfd_vol_top_priv {