Change directory name generation function for queue indexes and vhosts.

It was a mistake to relate on md5(term_to_binary(..)) to generate
vhost and queue directory name, since term_to_binary format can
change.
Migration functions take care of renaming directories.

2 files changed, 66 insertions, 47 deletions

diff --git a/src/rabbit_queue_index.erl b/src/rabbit_queue_index.erl
index 123bfaba25..7416ede4b8 100644
--- a/src/rabbit_queue_index.erl
+++ b/src/rabbit_queue_index.erl
@@ -116,6 +116,7 @@
 %% ---- Journal details ----
 
 -define(JOURNAL_FILENAME, "journal.jif").
+-define(QUEUE_NAME_STUB_FILE, ".queue_name").
 
 -define(PUB_PERSIST_JPREFIX, 2#00).
 -define(PUB_TRANS_JPREFIX,   2#01).
@@ -204,7 +205,9 @@
   %% optimisation
   pre_publish_cache,
   %% optimisation
-  delivered_cache}).
+  delivered_cache,
+  %% queue name resource record
+  queue_name}).
 
 -record(segment, {
   %% segment ID (an integer)
@@ -295,7 +298,8 @@ erase(Name) ->
     erase_index_dir(Dir).
 
 %% used during variable queue purge when there are no pending acks
-reset_state(#qistate{ dir            = Dir,
+reset_state(#qistate{ queue_name     = Name,
+                      dir            = Dir,
                       on_sync        = OnSyncFun,
                       on_sync_msg    = OnSyncMsgFun,
                       journal_handle = JournalHdl }) ->
@@ -304,7 +308,7 @@ reset_state(#qistate{ dir            = Dir,
              _         -> file_handle_cache:close(JournalHdl)
          end,
     ok = erase_index_dir(Dir),
-    blank_state_dir_funs(Dir, OnSyncFun, OnSyncMsgFun).
+    blank_state_name_dir_funs(Name, Dir, OnSyncFun, OnSyncMsgFun).
 
 init(Name, OnSyncFun, OnSyncMsgFun) ->
     State = #qistate { dir = Dir } = blank_state(Name),
@@ -520,32 +524,6 @@ start(VHost, DurableQueueNames) ->
     {OrderedTerms, {fun queue_index_walker/1, {start, DurableQueueNames}}}.
 
 
-read_global_recovery_terms(DurableQueueNames) ->
-    ok = rabbit_recovery_terms:open_global_table(),
-
-    DurableTerms =
-        lists:foldl(
-          fun(QName, RecoveryTerms) ->
-                  DirName = queue_name_to_dir_name(QName),
-                  RecoveryInfo = case rabbit_recovery_terms:read_global(DirName) of
-                                     {error, _}  -> non_clean_shutdown;
-                                     {ok, Terms} -> Terms
-                                 end,
-                  [RecoveryInfo | RecoveryTerms]
-          end, [], DurableQueueNames),
-
-    ok = rabbit_recovery_terms:close_global_table(),
-    %% The backing queue interface requires that the queue recovery terms
-    %% which come back from start/1 are in the same order as DurableQueueNames
-    OrderedTerms = lists:reverse(DurableTerms),
-    {OrderedTerms, {fun queue_index_walker/1, {start, DurableQueueNames}}}.
-
-cleanup_global_recovery_terms() ->
-    rabbit_file:recursive_delete([filename:join([queues_base_dir(), "queues"])]),
-    rabbit_recovery_terms:delete_global_table(),
-    ok.
-
-
 stop(VHost) -> rabbit_recovery_terms:stop(VHost).
 
 all_queue_directory_names(VHost) ->
@@ -567,10 +545,9 @@ erase_index_dir(Dir) ->
     end.
 
 blank_state(QueueName) ->
-    blank_state_dir(queue_dir(QueueName)).
-
-blank_state_dir(Dir) ->
-    blank_state_dir_funs(Dir,
+    Dir = queue_dir(QueueName),
+    blank_state_name_dir_funs(QueueName,
+                         Dir,
                          fun (_) -> ok end,
                          fun (_) -> ok end).
 
@@ -581,7 +558,20 @@ queue_dir(#resource{ virtual_host = VHost } = QueueName) ->
     QueueDir = queue_name_to_dir_name(QueueName),
     filename:join([VHostDir, "queues", QueueDir]).
 
-blank_state_dir_funs(Dir, OnSyncFun, OnSyncMsgFun) ->
+queue_name_to_dir_name(#resource { kind = queue,
+                                   virtual_host = VHost,
+                                   name = QName }) ->
+    <<Num:128>> = erlang:md5(<<"queue", VHost/binary, QName/binary>>),
+    rabbit_misc:format("~.36B", [Num]).
+
+queue_name_to_dir_name_legacy(Name = #resource { kind = queue }) ->
+    <<Num:128>> = erlang:md5(term_to_binary_compat:queue_name_to_binary(Name)),
+    rabbit_misc:format("~.36B", [Num]).
+
+queues_base_dir() ->
+    rabbit_mnesia:dir().
+
+blank_state_name_dir_funs(Name, Dir, OnSyncFun, OnSyncMsgFun) ->
     {ok, MaxJournal} =
         application:get_env(rabbit, queue_index_max_journal_entries),
     #qistate { dir                 = Dir,
@@ -594,7 +584,8 @@ blank_state_dir_funs(Dir, OnSyncFun, OnSyncMsgFun) ->
                unconfirmed         = gb_sets:new(),
                unconfirmed_msg     = gb_sets:new(),
                pre_publish_cache   = [],
-               delivered_cache     = [] }.
+               delivered_cache     = [],
+               queue_name          = Name }.
 
 init_clean(RecoveredCounts, State) ->
     %% Load the journal. Since this is a clean recovery this (almost)
@@ -690,13 +681,6 @@ recover_message(false,     _, no_del,  RelSeq, {Segment, DirtyCount}) ->
                     add_to_journal(RelSeq, del, Segment)),
      DirtyCount + 2}.
 
-queue_name_to_dir_name(Name = #resource { kind = queue }) ->
-    <<Num:128>> = erlang:md5(term_to_binary_compat:queue_name_to_binary(Name)),
-    rabbit_misc:format("~.36B", [Num]).
-
-queues_base_dir() ->
-    rabbit_mnesia:dir().
-
 %%----------------------------------------------------------------------------
 %% msg store startup delta function
 %%----------------------------------------------------------------------------
@@ -890,9 +874,11 @@ append_journal_to_segment(#segment { journal_entries = JEntries,
     end.
 
 get_journal_handle(State = #qistate { journal_handle = undefined,
-                                      dir = Dir }) ->
+                                      dir = Dir,
+                                      queue_name = Name }) ->
     Path = filename:join(Dir, ?JOURNAL_FILENAME),
     ok = rabbit_file:ensure_dir(Path),
+    ok = ensure_queue_name_stub_file(Dir, Name),
     {ok, Hdl} = file_handle_cache:open_with_absolute_path(
                   Path, ?WRITE_MODE, [{write_buffer, infinity}]),
     {Hdl, State #qistate { journal_handle = Hdl }};
@@ -1413,7 +1399,8 @@ store_msg_segment(_) ->
 
 
 
-
+%%----------------------------------------------------------------------------
+%% Migration functions
 %%----------------------------------------------------------------------------
 
 foreach_queue_index(Funs) ->
@@ -1467,18 +1454,50 @@ drive_transform_fun(Fun, Hdl, Contents) ->
 
 move_to_per_vhost_stores(#resource{} = QueueName) ->
     OldQueueDir = filename:join([queues_base_dir(), "queues",
-                                 queue_name_to_dir_name(QueueName)]),
+                                 queue_name_to_dir_name_legacy(QueueName)]),
     NewQueueDir = queue_dir(QueueName),
     case rabbit_file:is_dir(OldQueueDir) of
         true  ->
             ok = rabbit_file:ensure_dir(NewQueueDir),
-            ok = rabbit_file:rename(OldQueueDir, NewQueueDir);
+            ok = rabbit_file:rename(OldQueueDir, NewQueueDir),
+            ok = ensure_queue_name_stub_file(NewQueueDir, QueueName);
         false ->
             rabbit_log:info("Queue index directory not found for queue ~p~n",
                             [QueueName])
     end,
     ok.
 
+ensure_queue_name_stub_file(Dir, #resource{virtual_host = VHost, name = QName}) ->
+    QueueNameFile = filename:join(Dir, ?QUEUE_NAME_STUB_FILE),
+    file:write_file(QueueNameFile, <<"VHOST: ", VHost/binary, "\n",
+                                     "QUEUE: ", QName/binary, "\n">>).
+
+read_global_recovery_terms(DurableQueueNames) ->
+    ok = rabbit_recovery_terms:open_global_table(),
+
+    DurableTerms =
+        lists:foldl(
+          fun(QName, RecoveryTerms) ->
+                  DirName = queue_name_to_dir_name_legacy(QName),
+                  RecoveryInfo = case rabbit_recovery_terms:read_global(DirName) of
+                                     {error, _}  -> non_clean_shutdown;
+                                     {ok, Terms} -> Terms
+                                 end,
+                  [RecoveryInfo | RecoveryTerms]
+          end, [], DurableQueueNames),
+
+    ok = rabbit_recovery_terms:close_global_table(),
+    %% The backing queue interface requires that the queue recovery terms
+    %% which come back from start/1 are in the same order as DurableQueueNames
+    OrderedTerms = lists:reverse(DurableTerms),
+    {OrderedTerms, {fun queue_index_walker/1, {start, DurableQueueNames}}}.
+
+cleanup_global_recovery_terms() ->
+    rabbit_file:recursive_delete([filename:join([queues_base_dir(), "queues"])]),
+    rabbit_recovery_terms:delete_global_table(),
+    ok.
+
+
 update_recovery_term(#resource{virtual_host = VHost} = QueueName, Term) ->
     Key = queue_name_to_dir_name(QueueName),
     rabbit_recovery_terms:store(VHost, Key, Term).
diff --git a/src/rabbit_vhost.erl b/src/rabbit_vhost.erl
index 1d1ea16cca..c712015170 100644
--- a/src/rabbit_vhost.erl
+++ b/src/rabbit_vhost.erl
@@ -213,7 +213,7 @@ set_limits(VHost = #vhost{}, Limits) ->
 
 
 dir(Vhost) ->
-    <<Num:128>> = erlang:md5(term_to_binary(Vhost)),
+    <<Num:128>> = erlang:md5(Vhost),
     rabbit_misc:format("~.36B", [Num]).
 
 msg_store_dir_path(VHost) ->