Fix lots of bugs due to newer kernel 5.8 in Ubuntu 20.04, and OpenZFS v0.8:

1. clone_extents_to() didn't handle partial clones, and now it does.

2. OpenZFS has a bug in SEEK_DATA which caused empty clones, we use a hacky
workaround to fix it.

3. mapped_file_handle now fails loudly if it fails to allocate the map due
to VMA exhaustion. This closes off a ton of unpleasant surprise in heavily
loaded applications.

4. If your Linux kernel was old enough, or you are on ZFS, renaming a
mapped_file_handle caused internal state corruption which led to lots of
bad things, including `bad_file_descriptor` errors.

5. On Windows, renaming a mapped_file_handle now tears down and restores
the maps, as you cannot rename a file with open maps.

1 files changed, 0 insertions, 1 deletions

diff --git a/test/tests/mapped.cpp b/test/tests/mapped.cpp
index d865f71d..f978a372 100644
--- a/test/tests/mapped.cpp
+++ b/test/tests/mapped.cpp
@@ -73,7 +73,6 @@ static inline void TestMappedView2()
     filesystem::remove("testfile", ec);
   }
   mapped_file_handle mfh = mapped_file_handle::mapped_file(1024 * 1024, {}, "testfile", file_handle::mode::write, file_handle::creation::if_needed, file_handle::caching::all, file_handle::flag::unlink_on_first_close).value();
-  BOOST_CHECK(mfh.address() == nullptr);
   mfh.truncate(10000 * sizeof(int)).value();
   byte *addr = mfh.address();
   BOOST_CHECK(addr != nullptr);