re-commit r52152

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52159 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,13 @@
+Sun Oct 18 08:26:51 2015  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* io.c (fptr_finalize): don't release gvl if fptr is not writable.
+	  writable fd may block on close(2) when it's on NFS. But readonly
+	  fd doesn't. [Bug #11559]
+	  result: make benchmark OPTS="-p bm_require_t -e ruby-trunk -e ruby-2.2.2"
+	    build-ruby:             0.171
+	    ruby 2.3.0dev(r52151):  0.659
+	    ruby 2.2.0p95 (r50295): 0.834
+
 Sun Oct 18 09:32:58 2015  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* file.c (ruby_is_fd_loadable): this should be fail if st_mode is

io.c

@@ -4263,6 +4263,7 @@ fptr_finalize(rb_io_t *fptr, int noraise)
     VALUE err = Qnil;
     int fd = fptr->fd;
     FILE *stdio_file = fptr->stdio_file;
+    int mode = fptr->mode;
 
     if (fptr->writeconv) {
 	if (fptr->write_lock && !noraise) {
@@ -4303,7 +4304,11 @@ fptr_finalize(rb_io_t *fptr, int noraise)
 	/* fptr->fd may be closed even if close fails.
          * POSIX doesn't specify it.
          * We assumes it is closed.  */
-	if ((maygvl_close(fd, noraise) < 0) && NIL_P(err))
+
+	/**/
+	int keepgvl = !(mode & FMODE_WRITABLE);
+	keepgvl |= noraise;
+	if ((maygvl_close(fd, keepgvl) < 0) && NIL_P(err))
 	    err = noraise ? Qtrue : INT2NUM(errno);
     }