On 07/26/2018 02:47 PM, Jesse Williamson wrote:
Hi folks,
I'm working on a feature to make libradosstriper optional:
https://github.com/ceph/ceph/pull/21983
While I believe I'm in the home stretch, I'm also getting a link error
that I find mysterious. In the above PR, I have[1]:
target_link_libraries(rados librados global ${BLKID_LIBRARIES}
${CMAKE_DL_LIBS})
if(WITH_LIBRADOSSTRIPER)
target_link_libraries(rados radosstriper)
else(WITH_LIBRADOSSTRIPER)
target_link_libraries(rados cls_lock_client)
endif(WITH_LIBRADOSSTRIPER)
...notice the line linking in cls_lock_client. With this present,
things look ok. Remove it, and for me this fails to compile (link
errors follow text).
It looks like cls_lock_client should already be linked into librados,
as per src/librados/CMakeLists.txt:
target_link_libraries(librados PRIVATE
osdc ceph-common cls_lock_client
${BLKID_LIBRARIES} ${CRYPTO_LIBS} ${EXTRALIBS})
the PRIVATE there means that the link dependencies aren't transitive -
so while rados will link with librados, it won't link directly with
cls_lock_client
I wondered if it might have been related to name mangling (usually
something I've seen when extern "C" is used and then another TU uses
C++ linkage), but although the symbols in cls_lock_client.h are marked
"export", that's the default linkage for C++ so I don't think there is
anything in the source code.
That leaves me to wonder if it's a cmake thing. Perhaps I'm missing
something obvious?
====
To reproduce:
0) Make sure that "cls_lock_client" isn't included, by patching the above
(as per Kefu):
diff --git a/src/tools/CMakeLists.txt b/src/tools/CMakeLists.txt
index ad8c2f81a1..b63654c09f 100644
--- a/src/tools/CMakeLists.txt
+++ b/src/tools/CMakeLists.txt
@@ -10,10 +10,10 @@ add_executable(rados ${rados_srcs})
target_link_libraries(rados librados global ${BLKID_LIBRARIES}
${CMAKE_DL_LIBS})
if(WITH_LIBRADOSSTRIPER)
-target_link_libraries(rados radosstriper)
-else(WITH_LIBRADOSSTRIPER)
-target_link_libraries(rados cls_lock_client)
-endif(WITH_LIBRADOSSTRIPER)
+ target_link_libraries(rados radosstriper)
+ #else()
+ #target_link_libraries(rados cls_lock_client)
+endif()
install(TARGETS rados DESTINATION bin)
if(WITH_TESTS)
1) Compile with (note -DWITH_LIBRADOSSTRIPER=0) the following:
./do_cmake.sh -DHAS_VTA=0 -DWITH_LEVELDB=0 -DWITH_CCACHE=1 -DWITH_LTTNG=0
-DWITH_BABELTRACE=0 -DWITH_LZ4=0 -DWITH_LIBRADOSSTRIPER=0
cd build && make rados
2) I then see the errors listed below. Note that compiling with
-DWITH_LIBRADOSSTRIPER=1, which is the default, should work just fine.
Am I missing something obvious? Some cmake magic?
I've had one other person not be able to reproduce this. Does it also
work for everyone else (with -DWITH_LIBRADOSSTRIPER=0)? If so... what
version of cmake are folks using?
Appreciatively,
-Jesse
CMakeFiles/rados.dir/rados/rados.cc.o: In function `do_lock_cmd':
/home/jwilliamson/work/ceph-libradosstriper/src/tools/rados/rados.cc:1246:
undefined reference to
`rados::cls::lock::get_lock_info(librados::IoCtx*,
std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&, std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&,
std::map<rados::cls::lock::locker_id_t,
rados::cls::lock::locker_info_t,
std::less<rados::cls::lock::locker_id_t>,
std::allocator<std::pair<rados::cls::lock::locker_id_t const,
rados::cls::lock::locker_info_t> > >*, ClsLockType*,
std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> >*)'
/home/jwilliamson/work/ceph-libradosstriper/src/tools/rados/rados.cc:1309:
undefined reference to
`rados::cls::lock::Lock::break_lock(librados::IoCtx*,
std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&, entity_name_t const&)'
/home/jwilliamson/work/ceph-libradosstriper/src/tools/rados/rados.cc:1283:
undefined reference to
`rados::cls::lock::Lock::lock_shared(librados::IoCtx*,
std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&)'
/home/jwilliamson/work/ceph-libradosstriper/src/tools/rados/rados.cc:1286:
undefined reference to
`rados::cls::lock::Lock::lock_exclusive(librados::IoCtx*,
std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&)'
/home/jwilliamson/work/ceph-libradosstriper/src/tools/rados/rados.cc:1216:
undefined reference to `rados::cls::lock::list_locks(librados::IoCtx*,
std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&,
std::__cxx11::list<std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> >,
std::allocator<std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > > >*)'
collect2: error: ld returned 1 exit status
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