diff --git a/src/http/modules/proxy/ngx_http_proxy_cache.c b/src/http/modules/proxy/ngx_http_proxy_cache.c
index e8e3b52..0bc7c61 100644
--- a/src/http/modules/proxy/ngx_http_proxy_cache.c
+++ b/src/http/modules/proxy/ngx_http_proxy_cache.c
@@ -216,6 +216,30 @@
 }
 
 
+#if 0
+
+static void ngx_http_proxy_cache_busy_lock(ngx_http_proxy_ctx_t *p)
+{
+    rc = ngx_http_busy_lock(p->lcf->busy_lock, p->cache->ctx.md5);
+
+    if (rc == NGX_OK) {
+        ngx_http_proxy_request_upstream(p);
+    }
+
+    if (rc == NGX_AGAIN) {
+        if (p->busy_lock_time) {
+            ngx_add_timer(p->request->connection->read, 1000);
+            return;
+        }
+    }
+
+    rc == NGX_ERROR
+    check waitn
+}
+
+#endif
+
+
 int ngx_http_proxy_send_cached_response(ngx_http_proxy_ctx_t *p)
 {
     int                  rc, len, i;
@@ -428,10 +452,21 @@
 
 int ngx_http_proxy_update_cache(ngx_http_proxy_ctx_t *p)
 {
+    ngx_event_pipe_t  *ep;
+
     if (p->cache == NULL) {
         return NGX_OK;
     }
 
+    ep = p->upstream->event_pipe;
+
+    if (p->cache->ctx.length == -1) {
+        /* TODO: test rc */
+        ngx_write_file(&ep->temp_file->file,
+                       (char *) &ep->read_length, sizeof(off_t),
+                       offsetof(ngx_http_cache_header_t, length));
+    }
+
     return ngx_http_cache_update_file(p->request, &p->cache->ctx,
-                               &p->upstream->event_pipe->temp_file->file.name);
+                                      &ep->temp_file->file.name);
 }
diff --git a/src/http/modules/proxy/ngx_http_proxy_handler.c b/src/http/modules/proxy/ngx_http_proxy_handler.c
index 860ba7a..a284956 100644
--- a/src/http/modules/proxy/ngx_http_proxy_handler.c
+++ b/src/http/modules/proxy/ngx_http_proxy_handler.c
@@ -266,7 +266,9 @@
     ngx_memzero(p->state, sizeof(ngx_http_proxy_state_t));
 
 
-    if (!p->lcf->cache) {
+    if (!p->lcf->cache
+        || (r->method != NGX_HTTP_GET && r->method != NGX_HTTP_HEAD))
+    {
         p->state->cache = NGX_HTTP_PROXY_CACHE_PASS;
 
     } else if (r->bypass_cache) {
@@ -290,16 +292,16 @@
 
     rc = ngx_http_proxy_get_cached_response(p);
 
+    if (rc == NGX_DONE || rc == NGX_HTTP_INTERNAL_SERVER_ERROR) {
+        return rc;
+    }
+
     p->valid_header_in = 1;
 
     if (rc == NGX_OK) {
         return ngx_http_proxy_send_cached_response(p);
     }
 
-    if (rc == NGX_HTTP_INTERNAL_SERVER_ERROR) {
-        return rc;
-    }
-
     /* rc == NGX_DECLINED || NGX_HTTP_CACHE_STALE || NGX_HTTP_CACHE_AGED */
 
     return ngx_http_proxy_request_upstream(p);
@@ -312,8 +314,7 @@
                   "finalize http proxy request");
 
     if (p->upstream->peer.connection) {
-        ngx_http_proxy_close_connection(p->upstream->peer.connection);
-        p->upstream->peer.connection = NULL;
+        ngx_http_proxy_close_connection(p);
     }
 
     if (p->header_sent
@@ -329,8 +330,17 @@
 }
 
 
-void ngx_http_proxy_close_connection(ngx_connection_t *c)
+void ngx_http_proxy_close_connection(ngx_http_proxy_ctx_t *p)
 {
+    ngx_connection_t  *c;
+
+    c = p->upstream->peer.connection;
+    p->upstream->peer.connection = NULL;
+
+    if (p->lcf->busy_lock) {
+        p->lcf->busy_lock->conn_n--;
+    }
+
     ngx_log_debug(c->log, "proxy close connection: %d" _ c->fd);
 
     if (c->fd == -1) {
@@ -505,6 +515,13 @@
 
     if (conf->busy_lock && conf->cache && conf->busy_lock->busy == NULL) {
 
+        /* ngx_alloc_shared() */
+        conf->busy_lock->busy_mask =
+                     ngx_palloc(cf->pool, (conf->busy_lock->max_conn + 7) / 8);
+        if (conf->busy_lock->busy_mask == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
         /* 16 bytes are 128 bits of the md5 */
 
         /* ngx_alloc_shared() */
diff --git a/src/http/modules/proxy/ngx_http_proxy_handler.h b/src/http/modules/proxy/ngx_http_proxy_handler.h
index 6e4b084..919a0af 100644
--- a/src/http/modules/proxy/ngx_http_proxy_handler.h
+++ b/src/http/modules/proxy/ngx_http_proxy_handler.h
@@ -140,6 +140,7 @@
 
     ngx_hunk_t                   *header_in;
 
+    time_t                        busy_lock_time;
 
     unsigned                      accel:1;
 
@@ -188,7 +189,7 @@
 
 size_t ngx_http_proxy_log_error(void *data, char *buf, size_t len);
 void ngx_http_proxy_finalize_request(ngx_http_proxy_ctx_t *p, int rc);
-void ngx_http_proxy_close_connection(ngx_connection_t *c);
+void ngx_http_proxy_close_connection(ngx_http_proxy_ctx_t *p);
 
 int ngx_http_proxy_parse_status_line(ngx_http_proxy_ctx_t *p);
 int ngx_http_proxy_copy_header(ngx_http_proxy_ctx_t *p,
diff --git a/src/http/modules/proxy/ngx_http_proxy_upstream.c b/src/http/modules/proxy/ngx_http_proxy_upstream.c
index cee93ee..c66c164 100644
--- a/src/http/modules/proxy/ngx_http_proxy_upstream.c
+++ b/src/http/modules/proxy/ngx_http_proxy_upstream.c
@@ -11,6 +11,8 @@
 static ngx_chain_t *ngx_http_proxy_create_request(ngx_http_proxy_ctx_t *p);
 static void ngx_http_proxy_init_upstream(void *data);
 static void ngx_http_proxy_reinit_upstream(ngx_http_proxy_ctx_t *p);
+static void ngx_http_proxy_upstream_busy_lock(ngx_http_proxy_ctx_t *p);
+static void ngx_http_proxy_upstream_busy_lock_handler(ngx_event_t *rev);
 static void ngx_http_proxy_connect(ngx_http_proxy_ctx_t *p);
 static void ngx_http_proxy_send_request(ngx_http_proxy_ctx_t *p);
 static void ngx_http_proxy_send_request_handler(ngx_event_t *wev);
@@ -264,7 +266,11 @@
 
     wctx->pool = r->pool;
 
-    ngx_http_proxy_connect(p);
+    if (p->lcf->busy_lock) {
+        ngx_http_proxy_upstream_busy_lock(p);
+    } else {
+        ngx_http_proxy_connect(p);
+    }
 }
 
 
@@ -306,6 +312,109 @@
 }
 
 
+static void ngx_http_proxy_upstream_busy_lock(ngx_http_proxy_ctx_t *p)
+{
+    int  ft_type;
+
+    if (p->lcf->busy_lock->conn_n < p->lcf->busy_lock->max_conn) {
+        p->lcf->busy_lock->conn_n++;
+
+        if (p->busy_lock_time) {
+            p->busy_lock_time = 0;
+            p->lcf->busy_lock->waiting_n--;
+        }
+
+        ngx_http_proxy_connect(p);
+        return;
+    }
+
+    if (p->busy_lock_time) {
+        if (p->busy_lock_time < p->lcf->busy_lock->timeout) {
+            ngx_add_timer(p->request->connection->read, 1000);
+            return;
+        }
+
+        p->lcf->busy_lock->waiting_n--;
+        ft_type = NGX_HTTP_PROXY_FT_BUSY_LOCK;
+
+    } else {
+        if (p->lcf->busy_lock->waiting_n < p->lcf->busy_lock->max_waiting) {
+            p->lcf->busy_lock->waiting_n++;
+            ngx_add_timer(p->request->connection->read, 1000);
+            p->request->connection->read->event_handler =
+                                     ngx_http_proxy_upstream_busy_lock_handler;
+            /* TODO: ngx_handle_level_read_event() */
+            return;
+        }
+
+        ft_type = NGX_HTTP_PROXY_FT_MAX_WAITING;
+    }
+
+    if (p->stale && (p->lcf->use_stale & ft_type)) {
+        ngx_http_proxy_finalize_request(p,
+                                        ngx_http_proxy_send_cached_response(p));
+        return;
+    }
+
+    ngx_http_proxy_finalize_request(p, NGX_HTTP_SERVICE_UNAVAILABLE);
+    return;
+}
+
+
+static void ngx_http_proxy_upstream_busy_lock_handler(ngx_event_t *rev)
+{
+    ngx_connection_t      *c;
+    ngx_http_request_t    *r;
+    ngx_http_proxy_ctx_t  *p;
+
+    ngx_log_debug(rev->log, "busy lock");
+
+    c = rev->data;
+    r = c->data;
+    p = ngx_http_get_module_ctx(r, ngx_http_proxy_module);
+    p->action = "waiting upstream in busy lock";
+
+    if (rev->timedout) {
+        rev->timedout = 0;
+        p->busy_lock_time++;
+        ngx_http_proxy_upstream_busy_lock(p);
+        return;
+    }
+
+    ngx_log_debug(rev->log, "client sent while busy lock");
+
+    /*
+     * TODO: kevent() notify about error, otherwise we need to
+     * call ngx_peek(): recv(MGS_PEEK) to get errno. THINK about aio
+     * if there's no error we need to disable event.
+     */
+
+#if (HAVE_KQUEUE)
+
+    if ((ngx_event_flags & NGX_HAVE_KQUEUE_EVENT) && rev->kq_eof) {
+        p->lcf->busy_lock->waiting_n--;
+
+        ngx_del_timer(rev);
+
+        ngx_log_error(NGX_LOG_ERR, c->log, rev->kq_errno,
+                      "client() closed connection");
+
+        if (ngx_del_event(rev, NGX_READ_EVENT, NGX_CLOSE_EVENT) == NGX_ERROR) {
+            ngx_http_proxy_finalize_request(p, NGX_HTTP_INTERNAL_SERVER_ERROR);
+            return;
+        }
+
+        /* we have not HTTP code for the case when a client cancels a request */
+
+        ngx_http_proxy_finalize_request(p, 0);
+        return;
+    }
+
+#endif
+
+}
+
+
 static void ngx_http_proxy_connect(ngx_http_proxy_ctx_t *p)
 {
     int                      rc;
@@ -1011,8 +1120,7 @@
         }
 
         if (ep->upstream_done || ep->upstream_eof || ep->upstream_error) {
-            ngx_http_proxy_close_connection(p->upstream->peer.connection);
-            p->upstream->peer.connection = NULL;
+            ngx_http_proxy_close_connection(p);
         }
     }
 
@@ -1024,8 +1132,7 @@
 
     if (ep->downstream_error) {
         if (!p->cachable && p->upstream->peer.connection) {
-            ngx_http_proxy_close_connection(p->upstream->peer.connection);
-            p->upstream->peer.connection = NULL;
+            ngx_http_proxy_close_connection(p);
         }
  
         if (p->upstream->peer.connection == NULL) {
@@ -1080,8 +1187,7 @@
     }
 
     if (p->upstream->peer.connection) {
-        ngx_http_proxy_close_connection(p->upstream->peer.connection);
-        p->upstream->peer.connection = NULL;
+        ngx_http_proxy_close_connection(p);
     }
 
     if (status) {
@@ -1100,5 +1206,9 @@
         }
     }
 
-    ngx_http_proxy_connect(p);
+    if (p->lcf->busy_lock) {
+        ngx_http_proxy_upstream_busy_lock(p);
+    } else {
+        ngx_http_proxy_connect(p);
+    }
 }