我在Riak控制台上看到IO错误。我不确定原因是什么，因为目录的所有者是riak。这是错误的样子。
2018-01-25 23:18:06.922 [info] <0.2301.0>@riak_kv_vnode:maybe_create_hashtrees:234 riak_kv/730750818665451459101842416358141509827966271488: unable to start index_hashtree: {error,{{badmatch,{error,{db_open,"IO error: lock /var/lib/riak/anti_entropy/v0/730750818665451459101842416358141509827966271488/LOCK: already held by process"}}},[{hashtree,new_segment_store,2,[{file,"src/hashtree.erl"},{line,725}]},{hashtree,new,2,[{file,"src/hashtree.erl"},{line,246}]},{riak_kv_index_hashtree,do_new_tree,3,[{file,"src/riak_kv_index_hashtree.erl"},{line,712}]},{lists,foldl,3,[{file,"lists.erl"},{line,1248}]},{riak_kv_index_hashtree,init_trees,3,[{file,"src/riak_kv_index_hashtree.erl"},{line,565}]},{riak_kv_index_hashtree,init,1,[{file,"src/riak_kv_index_hashtree.erl"},{line,308}]},{gen_server,init_it,6,[{file,"gen_server.erl"},{line,304}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,239}]}]}}
2018-01-25 23:18:06.927 [info] <0.2315.0>@riak_kv_vnode:maybe_create_hashtrees:234 riak_kv/890602560248518965780370444936484965102833893376: unable to start index_hashtree: {error,{{badmatch,{error,{db_open,"IO error: lock /var/lib/riak/anti_entropy/v0/890602560248518965780370444936484965102833893376/LOCK: already held by process"}}},[{hashtree,new_segment_store,2,[{file,"src/hashtree.erl"},{line,725}]},{hashtree,new,2,[{file,"src/hashtree.erl"},{line,246}]},{riak_kv_index_hashtree,do_new_tree,3,[{file,"src/riak_kv_index_hashtree.erl"},{line,712}]},{lists,foldl,3,[{file,"lists.erl"},{line,1248}]},{riak_kv_index_hashtree,init_trees,3,[{file,"src/riak_kv_index_hashtree.erl"},{line,565}]},{riak_kv_index_hashtree,init,1,[{file,"src/riak_kv_index_hashtree.erl"},{line,308}]},{gen_server,init_it,6,[{file,"gen_server.erl"},{line,304}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,239}]}]}}
2018-01-25 23:18:06.928 [error] <0.27284.0> CRASH REPORT Process <0.27284.0> with 0 neighbours exited with reason: no match of right hand value {error,{db_open,"IO error: lock /var/lib/riak/anti_entropy/v0/890602560248518965780370444936484965102833893376/LOCK: already held by process"}} in hashtree:new_segment_store/2 line 725 in gen_server:init_it/6 line 328
关于问题可能是什么的任何想法？