glusterd: Run post hooks on a different thread

This change ensures post hooks can 'wait' if need be
and _not_ prevent glusterd from being able to run other operations
meanwhile.

Also ensures that post hook scripts are 'serialized'
between transactions. ie, post hook scripts of txn1 are completed
before post hook scripts of txn2 are started, where txn1 happens before
txn2.

Change-Id: Iaeb676737d8c67e7151127c8d1fd8c2891e10aee
BUG: 806996
Signed-off-by: Krishnan Parthasarathi <kp@gluster.com>
Reviewed-on: http://review.gluster.com/3476
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vijay@gluster.com>

1 files changed, 168 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-hooks.c b/xlators/mgmt/glusterd/src/glusterd-hooks.c
index ba428b0f3..54f14d87b 100644
--- a/xlators/mgmt/glusterd/src/glusterd-hooks.c
+++ b/xlators/mgmt/glusterd/src/glusterd-hooks.c
@@ -358,3 +358,171 @@ out:
         return ret;
 }
 
+int
+glusterd_hooks_post_stub_enqueue (char *scriptdir, glusterd_op_t op,
+                                  dict_t *op_ctx)
+{
+        int                     ret     = -1;
+        glusterd_hooks_stub_t   *stub   = NULL;
+        glusterd_hooks_private_t *hooks_priv = NULL;
+        glusterd_conf_t         *conf   = NULL;
+
+        conf = THIS->private;
+        hooks_priv = conf->hooks_priv;
+
+        ret = glusterd_hooks_stub_init (&stub, scriptdir, op, op_ctx);
+        if (ret)
+                goto out;
+
+        pthread_mutex_lock (&hooks_priv->mutex);
+        {
+                hooks_priv->waitcount++;
+                list_add_tail (&stub->all_hooks, &hooks_priv->list);
+                pthread_cond_signal (&hooks_priv->cond);
+        }
+        pthread_mutex_unlock (&hooks_priv->mutex);
+
+        ret = 0;
+out:
+        return ret;
+}
+
+int
+glusterd_hooks_stub_init (glusterd_hooks_stub_t **stub, char *scriptdir,
+                          glusterd_op_t op, dict_t *op_ctx)
+{
+        int                     ret             = -1;
+        glusterd_hooks_stub_t   *hooks_stub     = NULL;
+
+        GF_ASSERT (stub);
+        if (!stub)
+                goto out;
+
+        hooks_stub = GF_CALLOC (1, sizeof (*hooks_stub),
+                                gf_gld_mt_hooks_stub_t);
+        if (!hooks_stub)
+                goto out;
+
+        INIT_LIST_HEAD (&hooks_stub->all_hooks);
+        hooks_stub->op = op;
+        hooks_stub->scriptdir = gf_strdup (scriptdir);
+        if (!hooks_stub->scriptdir)
+                goto out;
+
+        hooks_stub->op_ctx = dict_copy_with_ref (op_ctx, hooks_stub->op_ctx);
+        if (!hooks_stub->op_ctx)
+                goto out;
+
+        *stub = hooks_stub;
+        ret = 0;
+out:
+        if (ret) {
+                gf_log (THIS->name, GF_LOG_ERROR, "Failed to initialize "
+                        "post hooks stub");
+                glusterd_hooks_stub_cleanup (hooks_stub);
+        }
+
+        return ret;
+}
+
+void
+glusterd_hooks_stub_cleanup (glusterd_hooks_stub_t *stub)
+{
+        if (!stub) {
+                gf_log_callingfn (THIS->name, GF_LOG_WARNING,
+                                  "hooks_stub is NULL");
+                return;
+        }
+
+        if (stub->op_ctx)
+                dict_unref (stub->op_ctx);
+
+        if (stub->scriptdir)
+                GF_FREE (stub->scriptdir);
+
+        if (stub)
+                GF_FREE (stub);
+}
+
+static void*
+hooks_worker (void *args)
+{
+        glusterd_conf_t *conf = NULL;
+        glusterd_hooks_private_t *hooks_priv = NULL;
+        glusterd_hooks_stub_t *stub = NULL;
+
+        THIS = args;
+        conf = THIS->private;
+        hooks_priv = conf->hooks_priv;
+
+        for (;;) {
+                pthread_mutex_lock (&hooks_priv->mutex);
+                {
+                        while (list_empty (&hooks_priv->list)) {
+                                pthread_cond_wait (&hooks_priv->cond,
+                                                   &hooks_priv->mutex);
+                        }
+                        stub = list_entry (hooks_priv->list.next,
+                                           glusterd_hooks_stub_t,
+                                           all_hooks);
+                        list_del_init (&stub->all_hooks);
+                        hooks_priv->waitcount--;
+
+                }
+                pthread_mutex_unlock (&hooks_priv->mutex);
+
+                glusterd_hooks_run_hooks (stub->scriptdir, stub->op,
+                                          stub->op_ctx, GD_COMMIT_HOOK_POST);
+                glusterd_hooks_stub_cleanup (stub);
+        }
+
+        return NULL;
+}
+
+int
+glusterd_hooks_priv_init (glusterd_hooks_private_t **new)
+{
+        int                      ret            = -1;
+        glusterd_hooks_private_t *hooks_priv    = NULL;
+
+        if (!new)
+                goto out;
+
+        hooks_priv = GF_CALLOC (1, sizeof (*hooks_priv),
+                                gf_gld_mt_hooks_priv_t);
+        if (!hooks_priv)
+                goto out;
+
+        pthread_mutex_init (&hooks_priv->mutex, NULL);
+        pthread_cond_init (&hooks_priv->cond, NULL);
+        INIT_LIST_HEAD (&hooks_priv->list);
+        hooks_priv->waitcount = 0;
+
+        *new = hooks_priv;
+        ret = 0;
+out:
+        return ret;
+}
+
+int
+glusterd_hooks_spawn_worker (xlator_t *this)
+{
+        int                       ret          = -1;
+        glusterd_conf_t           *conf        = NULL;
+        glusterd_hooks_private_t  *hooks_priv  = NULL;
+
+
+        ret = glusterd_hooks_priv_init (&hooks_priv);
+        if (ret)
+                goto out;
+
+        conf = this->private;
+        conf->hooks_priv = hooks_priv;
+        ret = pthread_create (&hooks_priv->worker, NULL, hooks_worker,
+                              (void *)this);
+        if (ret)
+                gf_log (this->name, GF_LOG_CRITICAL, "Failed to spawn post "
+                        "hooks worker thread");
+out:
+        return ret;
+}