# HG changeset patch
# User bobv
# Date 1292873424 18000
# Node ID 02895c6a2f82fd35cb2d4ca58aaf99297b1aa98c
# Parent  6da3527317ff705b59e93a3e79199a6d2381fc70
7007769: VM crashes with SIGBUS writing PerfData if tmp space is full
Summary: Fill perfdata file with zeros to verify available disk space
Reviewed-by: coleenp, kamg

diff -r 6da3527317ff -r 02895c6a2f82 src/os/linux/vm/perfMemory_linux.cpp
--- a/src/os/linux/vm/perfMemory_linux.cpp	Fri Dec 17 12:14:48 2010 +0000
+++ b/src/os/linux/vm/perfMemory_linux.cpp	Mon Dec 20 14:30:24 2010 -0500
@@ -635,7 +635,29 @@
     return -1;
   }
 
-  return fd;
+  // Verify that we have enough disk space for this file.
+  // We'll get random SIGBUS crashes on memory accesses if
+  // we don't.
+
+  for (size_t seekpos = 0; seekpos < size; seekpos += os::vm_page_size()) {
+    int zero_int = 0;
+    result = (int)os::seek_to_file_offset(fd, (jlong)(seekpos));
+    if (result == -1 ) break;
+    RESTARTABLE(::write(fd, &zero_int, 1), result);
+    if (result != 1) {
+      if (errno == ENOSPC) {
+        warning("Insufficient space for shared memory file:\n   %s\nTry using the -Djava.io.tmpdir= option to select an alternate temp location.\n", filename);
+      }
+      break;
+    }
+  }
+
+  if (result != -1) {
+    return fd;
+  } else {
+    RESTARTABLE(::close(fd), result);
+    return -1;
+  }
 }
 
 // open the shared memory file for the given user and vmid. returns