posix_fallocate isn't support on all filesystems

[sidneym]

Summary

Check the return from posix_fallocate and if the filesystem doesn't support it fall back to ftruncate.

[sidneym]

Remove braces

[• rafael]

Please don't duplicate the code in the compile time and runtime checks. Can you do something like

#if defined(HAVE_POSIX_FALLOCATE)

// If we have posix_fallocate use it. Unlike ftruncate it always allocates
// space, so we get an error if the disk is full.

int Err = ::posix_fallocate(FD, 0, Size);
if (!Err)

return std::error_code();

if (Err && Err != EOPNOTSUPP)

  return std::error_code(Err, std::generic_category());

// Add a comment about which file systems don't support posix_fallocate.

#endif

// Use ftruncate as a fallback. It may or may not allocate space. At least on
// OS X with HFS+ it does.
if (::ftruncate(FD, Size) == -1)
  return std::error_code(errno, std::generic_category());

[sidneym]

Removed duplicated code.

lib/Support/Unix/Path.inc

   // If we have posix_fallocate use it. Unlike ftruncate it always allocates
   // space, so we get an error if the disk is full.
   if (int Err = ::posix_fallocate(FD, 0, Size))
-    return std::error_code(Err, std::generic_category());
-#else
+    if (Err != EOPNOTSUPP)
+      return std::error_code(Err, std::generic_category());
+#endif
   // Use ftruncate as a fallback. It may or may not allocate space. At least on
   // OS X with HFS+ it does.
   if (::ftruncate(FD, Size) == -1)
     return std::error_code(errno, std::generic_category());
-#endif
 
   return std::error_code();
 }