cli: on error invoke cli_cmd_broadcast_response function in separate thread

There is a problem in current CLI framework
CLI holds the lock when processing command.
When processing quota list command, below sequence of steps executed in the
same thread and causing deadlock

1) CLI holds the lock
2) Send rpc_clnt_submit request to quotad for quota usage
3) If quotad is down, rpc_clnt_submit invokes cbk function with error
4) cbk function cli_quotad_getlimit_cbk tries to hold lock to broadcast
   the results and hangs, because same thread has already holding the lock

This patch fixes the problem by creating seperate thread for
broadcasting the result

Change-Id: I53be006eadf6aaf348083d9168535530d70a8ab3
BUG: 1242819
Signed-off-by: vmallika <vmallika@redhat.com>
Reviewed-on: http://review.gluster.org/11990
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>

1 files changed, 87 insertions, 7 deletions

diff --git a/cli/src/cli-rpc-ops.c b/cli/src/cli-rpc-ops.c
index c10554daaee..3df9226d9e9 100644
--- a/cli/src/cli-rpc-ops.c
+++ b/cli/src/cli-rpc-ops.c
@@ -3232,7 +3232,8 @@ out:
 }
 
 int
-print_quota_list_from_quotad (call_frame_t *frame, dict_t *rsp_dict)
+print_quota_list_from_quotad (call_frame_t *frame, dict_t *rsp_dict,
+                              int32_t list_count)
 {
         char             *path          = NULL;
         char             *default_sl    = NULL;
@@ -3244,11 +3245,11 @@ print_quota_list_from_quotad (call_frame_t *frame, dict_t *rsp_dict)
         quota_limits_t  *size_limits    = NULL;
         int32_t          type           = 0;
 
+        GF_ASSERT (frame);
+
         local = frame->local;
         gd_rsp_dict = local->dict;
 
-        GF_ASSERT (frame);
-
         ret = dict_get_int32 (rsp_dict, "type", &type);
         if (ret) {
                 gf_log ("cli", GF_LOG_ERROR, "Failed to get type");
@@ -3306,12 +3307,37 @@ print_quota_list_from_quotad (call_frame_t *frame, dict_t *rsp_dict)
                 goto out;
         }
 
+        if (list_count == 0) {
+                if (!(global_state->mode & GLUSTER_MODE_XML)) {
+                        print_quota_list_header (type);
+                } else {
+                        ret = cli_xml_output_vol_quota_limit_list_begin
+                                (local, 0, 0, NULL);
+                        if (ret) {
+                                gf_log ("cli", GF_LOG_ERROR, "Error in "
+                                        "printing xml output");
+                                goto out;
+                        }
+                }
+        }
+
         ret = print_quota_list_output (local, path, default_sl, &limits,
                                        &used_space, type);
 out:
         return ret;
 }
 
+void*
+cli_cmd_broadcast_response_detached (void *opaque)
+{
+        int32_t ret = 0;
+
+        ret = (intptr_t) opaque;
+        cli_cmd_broadcast_response (ret);
+
+        return NULL;
+}
+
 int
 cli_quotad_getlimit_cbk (struct rpc_req *req, struct iovec *iov,
                           int count, void *myframe)
@@ -3321,12 +3347,41 @@ cli_quotad_getlimit_cbk (struct rpc_req *req, struct iovec *iov,
         int                ret         = -1;
         dict_t            *dict        = NULL;
         call_frame_t      *frame       = NULL;
+        cli_local_t       *local       = NULL;
+        dict_t            *gd_rsp_dict = NULL;
+        int32_t            list_count  = 0;
+        pthread_t          th_id       = {0, };
 
-        if (-1 == req->rpc_status) {
+        frame = myframe;
+        GF_ASSERT (frame);
+
+        local = frame->local;
+        gd_rsp_dict = local->dict;
+
+        LOCK (&local->lock);
+        {
+                ret = dict_get_int32 (gd_rsp_dict, "quota-list-count",
+                                      &list_count);
+                if (ret)
+                        list_count = 0;
+                ret = dict_set_int32 (gd_rsp_dict, "quota-list-count",
+                                      list_count + 1);
+        }
+        UNLOCK (&local->lock);
+
+        if (ret) {
+                gf_log ("cli", GF_LOG_ERROR, "Failed to set "
+                        "quota-list-count in dict");
                 goto out;
         }
 
-        frame = myframe;
+        if (-1 == req->rpc_status) {
+                if (list_count == 0)
+                        cli_err ("Connection failed. Please check if quota "
+                                 "daemon is operational.");
+                ret = -1;
+                goto out;
+        }
 
         ret = xdr_to_generic (*iov, &rsp, (xdrproc_t)xdr_gf_cli_rsp);
         if (ret < 0) {
@@ -3357,11 +3412,36 @@ cli_quotad_getlimit_cbk (struct rpc_req *req, struct iovec *iov,
                                 "unserialize req-buffer to dictionary");
                         goto out;
                 }
-                print_quota_list_from_quotad (frame, dict);
+                print_quota_list_from_quotad (frame, dict, list_count);
         }
 
 out:
-        cli_cmd_broadcast_response (ret);
+        /* Bad Fix: CLI holds the lock to process a command.
+         * When processing quota list command, below sequence of steps executed
+         * in the same thread and causing deadlock
+         *
+         * 1) CLI holds the lock
+         * 2) Send rpc_clnt_submit request to quotad for quota usage
+         * 3) If quotad is down, rpc_clnt_submit invokes cbk function with error
+         * 4) cbk function cli_quotad_getlimit_cbk invokes
+         *    cli_cmd_broadcast_response which tries to hold lock to broadcast
+         *    the results and hangs, because same thread has already holding
+         *    the lock
+         *
+         * Broadcasting response in a seperate thread which is not a
+         * good fix. This needs to be re-visted with better solution
+         */
+        if (ret == -1) {
+                ret = pthread_create (&th_id, NULL,
+                                cli_cmd_broadcast_response_detached,
+                                (void *)-1);
+                if (ret)
+                        gf_log ("cli", GF_LOG_ERROR, "pthread_create failed: "
+                                "%s", strerror (errno));
+        } else {
+                cli_cmd_broadcast_response (ret);
+        }
+
         if (dict)
                 dict_unref (dict);