--- a/src/os/unix/ngx_files.h
+++ b/src/os/unix/ngx_files.h
@@ -18,13 +18,21 @@ typedef ino_t                    ngx_fil
 
 
 typedef struct {
+    u_char                      *name;
+    size_t                       size;
+    void                        *addr;
+    ngx_fd_t                     fd;
+    ngx_log_t                   *log;
+} ngx_file_mapping_t;
+
+
+typedef struct {
     DIR                         *dir;
     struct dirent               *de;
     struct stat                  info;
 
     unsigned                     type:8;
     unsigned                     valid_info:1;
-    unsigned                     valid_type:1;
 } ngx_dir_t;
 
 
@@ -65,6 +73,7 @@ typedef struct {
 #define NGX_FILE_OPEN            0
 #define NGX_FILE_TRUNCATE        O_CREAT|O_TRUNC
 #define NGX_FILE_APPEND          O_WRONLY|O_APPEND
+#define NGX_FILE_NONBLOCK        O_NONBLOCK
 
 #define NGX_FILE_DEFAULT_ACCESS  0644
 #define NGX_FILE_OWNER_ACCESS    0600
@@ -139,16 +148,23 @@ ngx_int_t ngx_set_file_time(u_char *name
 #define ngx_fd_info(fd, sb)      fstat(fd, sb)
 #define ngx_fd_info_n            "fstat()"
 
+#define ngx_link_info(file, sb)  lstat((const char *) file, sb)
+#define ngx_link_info_n          "lstat()"
+
 #define ngx_is_dir(sb)           (S_ISDIR((sb)->st_mode))
 #define ngx_is_file(sb)          (S_ISREG((sb)->st_mode))
 #define ngx_is_link(sb)          (S_ISLNK((sb)->st_mode))
-#define ngx_is_exec(sb)          ((sb)->st_mode & S_IXUSR)
+#define ngx_is_exec(sb)          (((sb)->st_mode & S_IXUSR) == S_IXUSR)
 #define ngx_file_access(sb)      ((sb)->st_mode & 0777)
 #define ngx_file_size(sb)        (sb)->st_size
 #define ngx_file_mtime(sb)       (sb)->st_mtime
 #define ngx_file_uniq(sb)        (sb)->st_ino
 
 
+ngx_int_t ngx_create_file_mapping(ngx_file_mapping_t *fm);
+void ngx_close_file_mapping(ngx_file_mapping_t *fm);
+
+
 #if (NGX_HAVE_CASELESS_FILESYSTEM)
 
 #define ngx_filename_cmp(s1, s2, n)  strncasecmp((char *) s1, (char *) s2, n)
@@ -200,31 +216,31 @@ ngx_int_t ngx_read_dir(ngx_dir_t *dir);
 #else
 #define ngx_de_namelen(dir)      ngx_strlen((dir)->de->d_name)
 #endif
-#define ngx_de_info(name, dir)   stat((const char *) name, &(dir)->info)
+
+static ngx_inline ngx_int_t
+ngx_de_info(u_char *name, ngx_dir_t *dir)
+{
+    dir->type = 0;
+    return stat((const char *) name, &dir->info);
+}
+
 #define ngx_de_info_n            "stat()"
 #define ngx_de_link_info(name, dir)  lstat((const char *) name, &(dir)->info)
 #define ngx_de_link_info_n       "lstat()"
 
 #if (NGX_HAVE_D_TYPE)
 
-#if (NGX_LINUX)
-
-/* XFS on Linux does not set dirent.d_type */
+/*
+ * some file systems (e.g. XFS on Linux and CD9660 on FreeBSD)
+ * do not set dirent.d_type
+ */
 
 #define ngx_de_is_dir(dir)                                                   \
     (((dir)->type) ? ((dir)->type == DT_DIR) : (S_ISDIR((dir)->info.st_mode)))
 #define ngx_de_is_file(dir)                                                  \
     (((dir)->type) ? ((dir)->type == DT_REG) : (S_ISREG((dir)->info.st_mode)))
 #define ngx_de_is_link(dir)                                                  \
-    (((dir)->type) ? ((dir)->type == DT_LINK) : (S_ISLNK((dir)->info.st_mode)))
-
-#else
-
-#define ngx_de_is_dir(dir)       ((dir)->type == DT_DIR)
-#define ngx_de_is_file(dir)      ((dir)->type == DT_REG)
-#define ngx_de_is_link(dir)      ((dir)->type == DT_LINK)
-
-#endif /* NGX_LINUX */
+    (((dir)->type) ? ((dir)->type == DT_LNK) : (S_ISLNK((dir)->info.st_mode)))
 
 #else
 
@@ -254,6 +270,28 @@ ngx_err_t ngx_unlock_fd(ngx_fd_t fd);
 #define ngx_unlock_fd_n          "fcntl(F_SETLK, F_UNLCK)"
 
 
+#if (NGX_HAVE_F_READAHEAD)
+
+#define NGX_HAVE_READ_AHEAD      1
+
+#define ngx_read_ahead(fd, n)    fcntl(fd, F_READAHEAD, (int) n)
+#define ngx_read_ahead_n         "fcntl(fd, F_READAHEAD)"
+
+#elif (NGX_HAVE_POSIX_FADVISE)
+
+#define NGX_HAVE_READ_AHEAD      1
+
+ngx_int_t ngx_read_ahead(ngx_fd_t fd, size_t n);
+#define ngx_read_ahead_n         "posix_fadvise(POSIX_FADV_SEQUENTIAL)"
+
+#else
+
+#define ngx_read_ahead(fd, n)    0
+#define ngx_read_ahead_n         "ngx_read_ahead_n"
+
+#endif
+
+
 #if (NGX_HAVE_O_DIRECT)
 
 ngx_int_t ngx_directio_on(ngx_fd_t fd);
@@ -292,6 +330,8 @@ size_t ngx_fs_bsize(u_char *name);
 ssize_t ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size,
     off_t offset, ngx_pool_t *pool);
 
+extern ngx_uint_t  ngx_file_aio;
+
 #endif