new file mode 100644
--- /dev/null
+++ b/src/core/ngx_open_file_cache.c
@@ -0,0 +1,733 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_event.h>
+
+
+/*
+ * open file cache caches
+ *    open file handles with stat() info;
+ *    directories stat() info;
+ *    files and directories errors: not found, access denied, etc.
+ */
+
+
+static void ngx_open_file_cache_cleanup(void *data);
+static void ngx_open_file_cleanup(void *data);
+static void ngx_close_cached_file(ngx_open_file_cache_t *cache,
+    ngx_cached_open_file_t *file, ngx_log_t *log);
+static ngx_int_t ngx_open_and_stat_file(u_char *name, ngx_open_file_info_t *of,
+    ngx_log_t *log);
+static void ngx_expire_old_cached_files(ngx_open_file_cache_t *cache,
+    ngx_uint_t n, ngx_log_t *log);
+static void ngx_open_file_cache_rbtree_insert_value(ngx_rbtree_node_t *temp,
+    ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
+static void ngx_open_file_cache_remove(ngx_event_t *ev);
+
+
+ngx_open_file_cache_t *
+ngx_open_file_cache_init(ngx_pool_t *pool, ngx_uint_t max, time_t inactive)
+{
+    ngx_rbtree_node_t      *sentinel;
+    ngx_pool_cleanup_t     *cln;
+    ngx_open_file_cache_t  *cache;
+
+    cache = ngx_palloc(pool, sizeof(ngx_open_file_cache_t));
+    if (cache == NULL) {
+        return NULL;
+    }
+
+    cache->list_head.prev = NULL;
+    cache->list_head.next = &cache->list_tail;
+
+    cache->list_tail.prev = &cache->list_head;
+    cache->list_tail.next = NULL;
+
+    sentinel = ngx_palloc(pool, sizeof(ngx_rbtree_node_t));
+    if (sentinel == NULL) {
+        return NULL;
+    }
+
+    ngx_rbtree_sentinel_init(sentinel);
+
+    cache->rbtree.root = sentinel;
+    cache->rbtree.sentinel = sentinel;
+    cache->rbtree.insert = ngx_open_file_cache_rbtree_insert_value;
+
+    cache->current = 0;
+    cache->max = max;
+    cache->inactive = inactive;
+
+    cln = ngx_pool_cleanup_add(pool, 0);
+    if (cln == NULL) {
+        return NULL;
+    }
+
+    cln->handler = ngx_open_file_cache_cleanup;
+    cln->data = cache;
+
+    return cache;
+}
+
+
+static void
+ngx_open_file_cache_cleanup(void *data)
+{
+    ngx_open_file_cache_t  *cache = data;
+
+    ngx_cached_open_file_t  *file;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
+                   "open file cache cleanup");
+
+    for ( ;; ) {
+
+        file = cache->list_tail.prev;
+
+        if (file == &cache->list_head) {
+            break;
+        }
+
+        file->next->prev = file->prev;
+        file->prev->next = file->next;
+
+        ngx_rbtree_delete(&cache->rbtree, &file->node);
+
+        cache->current--;
+
+        ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
+                       "delete cached open file: %s", file->name);
+
+        if (!file->err && !file->is_dir) {
+            file->close = 1;
+            file->count = 0;
+            ngx_close_cached_file(cache, file, ngx_cycle->log);
+
+        } else {
+            ngx_free(file->name);
+            ngx_free(file);
+        }
+    }
+
+    if (cache->current) {
+        ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
+                      "%d items still leave in open file cache",
+                      cache->current);
+    }
+
+    if (cache->rbtree.root != cache->rbtree.sentinel) {
+        ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
+                      "rbtree still is not empty in open file cache");
+
+    }
+}
+
+
+ngx_int_t
+ngx_open_cached_file(ngx_open_file_cache_t *cache, ngx_str_t *name,
+    ngx_open_file_info_t *of, ngx_pool_t *pool)
+{
+    time_t                          now;
+    uint32_t                        hash;
+    ngx_int_t                       rc;
+    ngx_rbtree_node_t              *node, *sentinel;
+    ngx_pool_cleanup_t             *cln;
+    ngx_cached_open_file_t         *file;
+    ngx_pool_cleanup_file_t        *clnf;
+    ngx_open_file_cache_event_t    *fev;
+    ngx_open_file_cache_cleanup_t  *ofcln;
+
+    of->err = 0;
+
+    if (cache == NULL) {
+
+        cln = ngx_pool_cleanup_add(pool, sizeof(ngx_pool_cleanup_file_t));
+        if (cln == NULL) {
+            return NGX_ERROR;
+        }
+
+        rc = ngx_open_and_stat_file(name->data, of, pool->log);
+
+        if (rc == NGX_OK && !of->is_dir) {
+            cln->handler = ngx_pool_cleanup_file;
+            clnf = cln->data;
+
+            clnf->fd = of->fd;
+            clnf->name = name->data;
+            clnf->log = pool->log;
+        }
+
+        return rc;
+    }
+
+    cln = ngx_pool_cleanup_add(pool, sizeof(ngx_open_file_cache_cleanup_t));
+    if (cln == NULL) {
+        return NGX_ERROR;
+    }
+
+    hash = ngx_crc32_long(name->data, name->len);
+
+    node = cache->rbtree.root;
+    sentinel = cache->rbtree.sentinel;
+
+    now = ngx_time();
+
+    while (node != sentinel) {
+
+        if (hash < node->key) {
+            node = node->left;
+            continue;
+        }
+
+        if (hash > node->key) {
+            node = node->right;
+            continue;
+        }
+
+        /* hash == node->key */
+
+        do {
+            file = (ngx_cached_open_file_t *) node;
+
+            rc = ngx_strcmp(name->data, file->name);
+
+            if (rc == 0) {
+
+                file->next->prev = file->prev;
+                file->prev->next = file->next;
+
+                if (file->event || now - file->created < of->retest) {
+                    if (file->err == 0) {
+                        of->fd = file->fd;
+                        of->uniq = file->uniq;
+                        of->mtime = file->mtime;
+                        of->size = file->size;
+
+                        of->is_dir = file->is_dir;
+                        of->is_file = file->is_file;
+                        of->is_link = file->is_link;
+                        of->is_exec = file->is_exec;
+
+                        if (!file->is_dir) {
+                            file->count++;
+                        }
+
+                    } else {
+                        of->err = file->err;
+                    }
+
+                    goto found;
+                }
+
+                ngx_log_debug4(NGX_LOG_DEBUG_CORE, pool->log, 0,
+                               "retest open file: %s, fd:%d, c:%d, e:%d",
+                               file->name, file->fd, file->count, file->err);
+
+                if (file->is_dir) {
+
+                    /*
+                     * chances that directory became file are very small
+                     * so test_dir flag allows to use a single ngx_file_info()
+                     * syscall instead of three syscalls
+                     */
+
+                    of->test_dir = 1;
+                }
+
+                rc = ngx_open_and_stat_file(name->data, of, pool->log);
+
+                if (rc != NGX_OK && (of->err == 0 || !of->errors)) {
+                    goto failed;
+                }
+
+                if (of->is_dir) {
+                    if (file->is_dir || file->err) {
+                        goto update;
+                    }
+
+                    /* file became directory */
+
+                } else if (of->err == 0) {  /* file */
+
+                    if (file->is_dir || file->err) {
+                        goto update;
+                    }
+
+                    if (of->uniq == file->uniq
+                        && of->mtime == file->mtime
+                        && of->size == file->size)
+                    {
+                        if (ngx_close_file(of->fd) == NGX_FILE_ERROR) {
+                            ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno,
+                                          ngx_close_file_n " \"%s\" failed",
+                                          name->data);
+                        }
+
+                        of->fd = file->fd;
+                        file->count++;
+
+                        goto renew;
+                    }
+
+                    /* file was changed */
+
+                } else { /* error to cache */
+
+                    if (file->err || file->is_dir) {
+                        goto update;
+                    }
+
+                    /* file was removed, etc. */
+                }
+
+                if (file->count == 0) {
+                    if (ngx_close_file(file->fd) == NGX_FILE_ERROR) {
+                        ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno,
+                                      ngx_close_file_n " \"%s\" failed",
+                                      name->data);
+                    }
+
+                    goto update;
+                }
+
+                ngx_rbtree_delete(&cache->rbtree, &file->node);
+
+                cache->current--;
+
+                file->close = 1;
+
+                goto create;
+            }
+
+            node = (rc < 0) ? node->left : node->right;
+
+        } while (node != sentinel && hash == node->key);
+
+        break;
+    }
+
+    /* not found */
+
+    file = NULL;
+
+    rc = ngx_open_and_stat_file(name->data, of, pool->log);
+
+    if (rc != NGX_OK && (of->err == 0 || !of->errors)) {
+        goto failed;
+    }
+
+create:
+
+    if (cache->current >= cache->max) {
+        ngx_expire_old_cached_files(cache, 0, pool->log);
+    }
+
+    file = ngx_alloc(sizeof(ngx_cached_open_file_t), pool->log);
+
+    if (file == NULL) {
+        goto failed;
+    }
+
+    file->name = ngx_alloc(name->len + 1, pool->log);
+
+    if (file->name == NULL) {
+        ngx_free(file);
+        file = NULL;
+        goto failed;
+    }
+
+    ngx_cpystrn(file->name, name->data, name->len + 1);
+
+    file->node.key = hash;
+
+    ngx_rbtree_insert(&cache->rbtree, &file->node);
+
+    cache->current++;
+
+    file->count = 0;
+
+update:
+
+    if (of->events
+        && (ngx_event_flags & NGX_USE_VNODE_EVENT)
+        && of->fd != NGX_INVALID_FILE)
+    {
+        file->event = ngx_calloc(sizeof(ngx_event_t), pool->log);
+        if (file->event== NULL) {
+            goto failed;
+        }
+
+        fev = ngx_alloc(sizeof(ngx_open_file_cache_event_t), pool->log);
+        if (fev == NULL) {
+            goto failed;
+        }
+
+        fev->fd = of->fd;
+        fev->file = file;
+        fev->cache = cache;
+
+        file->event->handler = ngx_open_file_cache_remove;
+        file->event->data = fev;
+
+        /*
+         * although vnode event may be called while ngx_cycle->poll
+         * destruction; however, cleanup procedures are run before any
+         * memory freeing and events will be canceled.
+         */
+
+        file->event->log = ngx_cycle->log;
+
+        if (ngx_add_event(file->event, NGX_VNODE_EVENT, NGX_ONESHOT_EVENT)
+            != NGX_OK)
+        {
+            ngx_free(file->event->data);
+            ngx_free(file->event);
+            goto failed;
+        }
+
+    } else {
+        file->event = NULL;
+    }
+
+    file->fd = of->fd;
+    file->err = of->err;
+
+    if (of->err == 0) {
+        file->uniq = of->uniq;
+        file->mtime = of->mtime;
+        file->size = of->size;
+
+        file->close = 0;
+
+        file->is_dir = of->is_dir;
+        file->is_file = of->is_file;
+        file->is_link = of->is_link;
+        file->is_exec = of->is_exec;
+
+        if (!of->is_dir) {
+            file->count++;
+        }
+    }
+
+renew:
+
+    file->created = now;
+
+found:
+
+    file->accessed = now;
+
+    /* add to the inactive list head */
+
+    file->next = cache->list_head.next;
+    file->next->prev = file;
+    file->prev = &cache->list_head;
+    cache->list_head.next = file;
+
+    ngx_log_debug4(NGX_LOG_DEBUG_CORE, pool->log, 0,
+                   "cached open file: %s, fd:%d, c:%d, e:%d",
+                   file->name, file->fd, file->count, file->err);
+
+    if (of->err == 0) {
+
+        if (!of->is_dir) {
+            cln->handler = ngx_open_file_cleanup;
+            ofcln = cln->data;
+
+            ofcln->cache = cache;
+            ofcln->file = file;
+            ofcln->log = pool->log;
+        }
+
+        return NGX_OK;
+    }
+
+    return NGX_ERROR;
+
+failed:
+
+    if (file && file->count == 0) {
+        ngx_rbtree_delete(&cache->rbtree, &file->node);
+
+        cache->current--;
+
+        if (ngx_close_file(file->fd) == NGX_FILE_ERROR) {
+            ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno,
+                          ngx_close_file_n " \"%s\" failed", file->name);
+        }
+
+        ngx_free(file->name);
+        ngx_free(file);
+    }
+
+    if (of->fd != NGX_INVALID_FILE) {
+        if (ngx_close_file(of->fd) == NGX_FILE_ERROR) {
+            ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno,
+                          ngx_close_file_n " \"%s\" failed", name->data);
+        }
+    }
+
+    return NGX_ERROR;
+}
+
+
+static ngx_int_t
+ngx_open_and_stat_file(u_char *name, ngx_open_file_info_t *of, ngx_log_t *log)
+{
+    ngx_fd_t         fd;
+    ngx_file_info_t  fi;
+
+    of->fd = NGX_INVALID_FILE;
+
+    if (of->test_dir) {
+
+        if (ngx_file_info(name, &fi) == -1) {
+            of->err = ngx_errno;
+
+            return NGX_ERROR;
+        }
+
+        of->uniq = ngx_file_uniq(&fi);
+        of->mtime = ngx_file_mtime(&fi);
+        of->size = ngx_file_size(&fi);
+        of->is_dir = ngx_is_dir(&fi);
+        of->is_file = ngx_is_file(&fi);
+        of->is_link = ngx_is_link(&fi);
+        of->is_exec = ngx_is_exec(&fi);
+
+        if (of->is_dir) {
+            return NGX_OK;
+        }
+    }
+
+    fd = ngx_open_file(name, NGX_FILE_RDONLY, NGX_FILE_OPEN, 0);
+
+    if (fd == NGX_INVALID_FILE) {
+        of->err = ngx_errno;
+        return NGX_ERROR;
+    }
+
+    if (ngx_fd_info(fd, &fi) == NGX_FILE_ERROR) {
+        ngx_log_error(NGX_LOG_CRIT, log, ngx_errno,
+                      ngx_fd_info_n " \"%s\" failed", name);
+
+        if (ngx_close_file(fd) == NGX_FILE_ERROR) {
+            ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
+                          ngx_close_file_n " \"%s\" failed", name);
+        }
+
+        return NGX_ERROR;
+    }
+
+    if (ngx_is_dir(&fi)) {
+        if (ngx_close_file(fd) == NGX_FILE_ERROR) {
+            ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
+                          ngx_close_file_n " \"%s\" failed", name);
+        }
+
+        fd = NGX_INVALID_FILE;
+    }
+
+    of->fd = fd;
+    of->uniq = ngx_file_uniq(&fi);
+    of->mtime = ngx_file_mtime(&fi);
+    of->size = ngx_file_size(&fi);
+    of->is_dir = ngx_is_dir(&fi);
+    of->is_file = ngx_is_file(&fi);
+    of->is_link = ngx_is_link(&fi);
+    of->is_exec = ngx_is_exec(&fi);
+
+    return NGX_OK;
+}
+
+
+static void
+ngx_open_file_cleanup(void *data)
+{
+    ngx_open_file_cache_cleanup_t  *c = data;
+
+    c->file->count--;
+
+    ngx_close_cached_file(c->cache, c->file, c->log);
+
+    /* drop one or two expired open files */
+    ngx_expire_old_cached_files(c->cache, 1, c->log);
+}
+
+
+static void
+ngx_close_cached_file(ngx_open_file_cache_t *cache,
+    ngx_cached_open_file_t *file, ngx_log_t *log)
+{
+    ngx_log_debug4(NGX_LOG_DEBUG_CORE, log, 0,
+                   "close cached open file: %s, fd:%d, c:%d, %d",
+                   file->name, file->fd, file->count, file->close);
+
+    if (!file->close) {
+
+        file->accessed = ngx_time();
+
+        if (cache->list_head.next != file) {
+
+            /* delete from inactive list */
+
+            file->next->prev = file->prev;
+            file->prev->next = file->next;
+
+            /* add to the inactive list head */
+
+            file->next = cache->list_head.next;
+            file->next->prev = file;
+            file->prev = &cache->list_head;
+            cache->list_head.next = file;
+        }
+
+        return;
+    }
+
+    if (file->event) {
+        (void) ngx_del_event(file->event, NGX_VNODE_EVENT,
+                             file->count ? NGX_FLUSH_EVENT : NGX_CLOSE_EVENT);
+
+        ngx_free(file->event->data);
+        ngx_free(file->event);
+        file->event = NULL;
+    }
+
+    if (file->count) {
+        return;
+    }
+
+    if (ngx_close_file(file->fd) == NGX_FILE_ERROR) {
+        ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
+                      ngx_close_file_n " \"%s\" failed", file->name);
+    }
+
+    ngx_free(file->name);
+    ngx_free(file);
+}
+
+
+static void
+ngx_expire_old_cached_files(ngx_open_file_cache_t *cache, ngx_uint_t n,
+    ngx_log_t *log)
+{
+    time_t                   now;
+    ngx_cached_open_file_t  *file;
+
+    now = ngx_time();
+
+    /*
+     * n == 1 deletes one or two inactive files
+     * n == 0 deletes least recently used file by force
+     *        and one or two inactive files
+     */
+
+    while (n < 3) {
+
+        file = cache->list_tail.prev;
+
+        if (file == &cache->list_head) {
+            return;
+        }
+
+        if (n++ != 0 && now - file->accessed <= cache->inactive) {
+            return;
+        }
+
+        file->next->prev = file->prev;
+        file->prev->next = file->next;
+
+        ngx_rbtree_delete(&cache->rbtree, &file->node);
+
+        cache->current--;
+
+        ngx_log_debug1(NGX_LOG_DEBUG_CORE, log, 0,
+                       "expire cached open file: %s", file->name);
+
+        if (!file->err && !file->is_dir) {
+            file->close = 1;
+            ngx_close_cached_file(cache, file, log);
+
+        } else {
+            ngx_free(file->name);
+            ngx_free(file);
+        }
+    }
+}
+
+
+static void
+ngx_open_file_cache_rbtree_insert_value(ngx_rbtree_node_t *temp,
+    ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
+{
+    ngx_rbtree_node_t       **p;
+    ngx_cached_open_file_t    *file, *file_temp;
+
+    for ( ;; ) {
+
+        if (node->key < temp->key) {
+
+            p = &temp->left;
+
+        } else if (node->key > temp->key) {
+
+            p = &temp->right;
+
+        } else { /* node->key == temp->key */
+
+            file = (ngx_cached_open_file_t *) node;
+            file_temp = (ngx_cached_open_file_t *) temp;
+
+            p = (ngx_strcmp(file->name, file_temp->name) < 0)
+                    ? &temp->left : &temp->right;
+        }
+
+        if (*p == sentinel) {
+            break;
+        }
+
+        temp = *p;
+    }
+
+    *p = node;
+    node->parent = temp;
+    node->left = sentinel;
+    node->right = sentinel;
+    ngx_rbt_red(node);
+}
+
+
+static void
+ngx_open_file_cache_remove(ngx_event_t *ev)
+{
+    ngx_cached_open_file_t       *file;
+    ngx_open_file_cache_event_t  *fev;
+
+    fev = ev->data;
+    file = fev->file;
+
+    file->next->prev = file->prev;
+    file->prev->next = file->next;
+
+    ngx_rbtree_delete(&fev->cache->rbtree, &file->node);
+
+    fev->cache->current--;
+
+    /* NGX_ONESHOT_EVENT was already deleted */
+    file->event = NULL;
+
+    file->close = 1;
+
+    ngx_close_cached_file(fev->cache, file, ev->log);
+
+    /* free memory only when fev->cache and fev->file are already not needed */
+
+    ngx_free(ev->data);
+    ngx_free(ev);
+}