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authorErlang/OTP <[email protected]>2009-11-20 14:54:40 +0000
committerErlang/OTP <[email protected]>2009-11-20 14:54:40 +0000
commit84adefa331c4159d432d22840663c38f155cd4c1 (patch)
treebff9a9c66adda4df2106dfd0e5c053ab182a12bd /lib/mnesia/src/mnesia_bup.erl
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The R13B03 release.OTP_R13B03
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+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 1996-2009. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+%%
+-module(mnesia_bup).
+-export([
+ %% Public interface
+ iterate/4,
+ read_schema/2,
+ fallback_bup/0,
+ fallback_exists/0,
+ tm_fallback_start/1,
+ create_schema/1,
+ install_fallback/1,
+ install_fallback/2,
+ uninstall_fallback/0,
+ uninstall_fallback/1,
+ traverse_backup/4,
+ traverse_backup/6,
+ make_initial_backup/3,
+ fallback_to_schema/0,
+ lookup_schema/2,
+ schema2bup/1,
+ refresh_cookie/2,
+
+ %% Internal
+ fallback_receiver/2,
+ install_fallback_master/2,
+ uninstall_fallback_master/2,
+ local_uninstall_fallback/2,
+ do_traverse_backup/7,
+ trav_apply/4
+ ]).
+
+-include("mnesia.hrl").
+-import(mnesia_lib, [verbose/2, dbg_out/2]).
+
+-record(restore, {mode, bup_module, bup_data}).
+
+-record(fallback_args, {opaque,
+ scope = global,
+ module = mnesia_monitor:get_env(backup_module),
+ use_default_dir = true,
+ mnesia_dir,
+ fallback_bup,
+ fallback_tmp,
+ skip_tables = [],
+ keep_tables = [],
+ default_op = keep_tables
+ }).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Backup iterator
+
+%% Reads schema section and iterates over all records in a backup.
+%%
+%% Fun(BunchOfRecords, Header, Schema, Acc) is applied when a suitable amount
+%% of records has been collected.
+%%
+%% BunchOfRecords will be [] when the iteration is done.
+iterate(Mod, Fun, Opaque, Acc) ->
+ R = #restore{bup_module = Mod, bup_data = Opaque},
+ case catch read_schema_section(R) of
+ {error, Reason} ->
+ {error, Reason};
+ {R2, {Header, Schema, Rest}} ->
+ case catch iter(R2, Header, Schema, Fun, Acc, Rest) of
+ {ok, R3, Res} ->
+ catch safe_apply(R3, close_read, [R3#restore.bup_data]),
+ {ok, Res};
+ {error, Reason} ->
+ catch safe_apply(R2, close_read, [R2#restore.bup_data]),
+ {error, Reason};
+ {'EXIT', Pid, Reason} ->
+ catch safe_apply(R2, close_read, [R2#restore.bup_data]),
+ {error, {'EXIT', Pid, Reason}};
+ {'EXIT', Reason} ->
+ catch safe_apply(R2, close_read, [R2#restore.bup_data]),
+ {error, {'EXIT', Reason}}
+ end
+ end.
+
+iter(R, Header, Schema, Fun, Acc, []) ->
+ case safe_apply(R, read, [R#restore.bup_data]) of
+ {R2, []} ->
+ Res = Fun([], Header, Schema, Acc),
+ {ok, R2, Res};
+ {R2, BupItems} ->
+ iter(R2, Header, Schema, Fun, Acc, BupItems)
+ end;
+iter(R, Header, Schema, Fun, Acc, BupItems) ->
+ Acc2 = Fun(BupItems, Header, Schema, Acc),
+ iter(R, Header, Schema, Fun, Acc2, []).
+
+safe_apply(R, write, [_, Items]) when Items =:= [] ->
+ R;
+safe_apply(R, What, Args) ->
+ Abort = fun(Re) -> abort_restore(R, What, Args, Re) end,
+ Mod = R#restore.bup_module,
+ case catch apply(Mod, What, Args) of
+ {ok, Opaque, Items} when What =:= read ->
+ {R#restore{bup_data = Opaque}, Items};
+ {ok, Opaque} when What =/= read->
+ R#restore{bup_data = Opaque};
+ {error, Re} ->
+ Abort(Re);
+ Re ->
+ Abort(Re)
+ end.
+
+abort_restore(R, What, Args, Reason) ->
+ Mod = R#restore.bup_module,
+ Opaque = R#restore.bup_data,
+ dbg_out("Restore aborted. ~p:~p~p -> ~p~n",
+ [Mod, What, Args, Reason]),
+ catch apply(Mod, close_read, [Opaque]),
+ throw({error, Reason}).
+
+fallback_to_schema() ->
+ Fname = fallback_bup(),
+ fallback_to_schema(Fname).
+
+fallback_to_schema(Fname) ->
+ Mod = mnesia_backup,
+ case read_schema(Mod, Fname) of
+ {error, Reason} ->
+ {error, Reason};
+ Schema ->
+ case catch lookup_schema(schema, Schema) of
+ {error, _} ->
+ {error, "No schema in fallback"};
+ List ->
+ {ok, fallback, List}
+ end
+ end.
+
+%% Opens Opaque reads schema and then close
+read_schema(Mod, Opaque) ->
+ R = #restore{bup_module = Mod, bup_data = Opaque},
+ case catch read_schema_section(R) of
+ {error, Reason} ->
+ {error, Reason};
+ {R2, {_Header, Schema, _}} ->
+ catch safe_apply(R2, close_read, [R2#restore.bup_data]),
+ Schema
+ end.
+
+%% Open backup media and extract schema
+%% rewind backup media and leave it open
+%% Returns {R, {Header, Schema}}
+read_schema_section(R) ->
+ case catch do_read_schema_section(R) of
+ {'EXIT', Reason} ->
+ catch safe_apply(R, close_read, [R#restore.bup_data]),
+ {error, {'EXIT', Reason}};
+ {error, Reason} ->
+ catch safe_apply(R, close_read, [R#restore.bup_data]),
+ {error, Reason};
+ {R2, {H, Schema, Rest}} ->
+ Schema2 = convert_schema(H#log_header.log_version, Schema),
+ {R2, {H, Schema2, Rest}}
+ end.
+
+do_read_schema_section(R) ->
+ R2 = safe_apply(R, open_read, [R#restore.bup_data]),
+ {R3, RawSchema} = safe_apply(R2, read, [R2#restore.bup_data]),
+ do_read_schema_section(R3, verify_header(RawSchema), []).
+
+do_read_schema_section(R, {ok, B, C, []}, Acc) ->
+ case safe_apply(R, read, [R#restore.bup_data]) of
+ {R2, []} ->
+ {R2, {B, Acc, []}};
+ {R2, RawSchema} ->
+ do_read_schema_section(R2, {ok, B, C, RawSchema}, Acc)
+ end;
+
+do_read_schema_section(R, {ok, B, C, [Head | Tail]}, Acc)
+ when element(1, Head) =:= schema ->
+ do_read_schema_section(R, {ok, B, C, Tail}, Acc ++ [Head]);
+
+do_read_schema_section(R, {ok, B, _C, Rest}, Acc) ->
+ {R, {B, Acc, Rest}};
+
+do_read_schema_section(_R, {error, Reason}, _Acc) ->
+ {error, Reason}.
+
+verify_header([H | RawSchema]) when is_record(H, log_header) ->
+ Current = mnesia_log:backup_log_header(),
+ if
+ H#log_header.log_kind =:= Current#log_header.log_kind ->
+ Versions = ["0.1", "1.1", Current#log_header.log_version],
+ case lists:member(H#log_header.log_version, Versions) of
+ true ->
+ {ok, H, Current, RawSchema};
+ false ->
+ {error, {"Bad header version. Cannot be used as backup.", H}}
+ end;
+ true ->
+ {error, {"Bad kind of header. Cannot be used as backup.", H}}
+ end;
+verify_header(RawSchema) ->
+ {error, {"Missing header. Cannot be used as backup.", catch hd(RawSchema)}}.
+
+refresh_cookie(Schema, NewCookie) ->
+ case lists:keysearch(schema, 2, Schema) of
+ {value, {schema, schema, List}} ->
+ Cs = mnesia_schema:list2cs(List),
+ Cs2 = Cs#cstruct{cookie = NewCookie},
+ Item = {schema, schema, mnesia_schema:cs2list(Cs2)},
+ lists:keyreplace(schema, 2, Schema, Item);
+
+ false ->
+ Reason = "No schema found. Cannot be used as backup.",
+ throw({error, {Reason, Schema}})
+ end.
+
+%% Convert schema items from an external backup
+%% If backup format is the latest, no conversion is needed
+%% All supported backup formats should have their converters
+%% here as separate function clauses.
+convert_schema("0.1", Schema) ->
+ convert_0_1(Schema);
+convert_schema("1.1", Schema) ->
+ %% The new backup format is a pure extension of the old one
+ Current = mnesia_log:backup_log_header(),
+ convert_schema(Current#log_header.log_version, Schema);
+convert_schema(Latest, Schema) ->
+ H = mnesia_log:backup_log_header(),
+ if
+ H#log_header.log_version =:= Latest ->
+ Schema;
+ true ->
+ Reason = "Bad backup header version. Cannot convert schema.",
+ throw({error, {Reason, H}})
+ end.
+
+%% Backward compatibility for 0.1
+convert_0_1(Schema) ->
+ case lists:keysearch(schema, 2, Schema) of
+ {value, {schema, schema, List}} ->
+ Schema2 = lists:keydelete(schema, 2, Schema),
+ Cs = mnesia_schema:list2cs(List),
+ convert_0_1(Schema2, [], Cs);
+ false ->
+ List = mnesia_schema:get_initial_schema(disc_copies, [node()]),
+ Cs = mnesia_schema:list2cs(List),
+ convert_0_1(Schema, [], Cs)
+ end.
+
+convert_0_1([{schema, cookie, Cookie} | Schema], Acc, Cs) ->
+ convert_0_1(Schema, Acc, Cs#cstruct{cookie = Cookie});
+convert_0_1([{schema, db_nodes, DbNodes} | Schema], Acc, Cs) ->
+ convert_0_1(Schema, Acc, Cs#cstruct{disc_copies = DbNodes});
+convert_0_1([{schema, version, Version} | Schema], Acc, Cs) ->
+ convert_0_1(Schema, Acc, Cs#cstruct{version = Version});
+convert_0_1([{schema, Tab, Def} | Schema], Acc, Cs) ->
+ Head =
+ case lists:keysearch(index, 1, Def) of
+ {value, {index, PosList}} ->
+ %% Remove the snmp "index"
+ P = PosList -- [snmp],
+ Def2 = lists:keyreplace(index, 1, Def, {index, P}),
+ {schema, Tab, Def2};
+ false ->
+ {schema, Tab, Def}
+ end,
+ convert_0_1(Schema, [Head | Acc], Cs);
+convert_0_1([Head | Schema], Acc, Cs) ->
+ convert_0_1(Schema, [Head | Acc], Cs);
+convert_0_1([], Acc, Cs) ->
+ [schema2bup({schema, schema, Cs}) | Acc].
+
+%% Returns Val or throw error
+lookup_schema(Key, Schema) ->
+ case lists:keysearch(Key, 2, Schema) of
+ {value, {schema, Key, Val}} -> Val;
+ false -> throw({error, {"Cannot lookup", Key}})
+ end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Backup compatibility
+
+%% Convert internal schema items to backup dito
+schema2bup({schema, Tab}) ->
+ {schema, Tab};
+schema2bup({schema, Tab, TableDef}) ->
+ {schema, Tab, mnesia_schema:cs2list(TableDef)}.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Create schema on the given nodes
+%% Requires that old schemas has been deleted
+%% Returns ok | {error, Reason}
+create_schema([]) ->
+ create_schema([node()]);
+create_schema(Ns) when is_list(Ns) ->
+ case is_set(Ns) of
+ true ->
+ create_schema(Ns, mnesia_schema:ensure_no_schema(Ns));
+ false ->
+ {error, {combine_error, Ns}}
+ end;
+create_schema(Ns) ->
+ {error, {badarg, Ns}}.
+
+is_set(List) when is_list(List) ->
+ ordsets:is_set(lists:sort(List));
+is_set(_) ->
+ false.
+
+create_schema(Ns, ok) ->
+ %% Ensure that we access the intended Mnesia
+ %% directory. This function may not be called
+ %% during startup since it will cause the
+ %% application_controller to get into deadlock
+ case mnesia_lib:ensure_loaded(?APPLICATION) of
+ ok ->
+ case mnesia_monitor:get_env(schema_location) of
+ ram ->
+ {error, {has_no_disc, node()}};
+ _ ->
+ case mnesia_schema:opt_create_dir(true, mnesia_lib:dir()) of
+ {error, What} ->
+ {error, What};
+ ok ->
+ Mod = mnesia_backup,
+ Str = mk_str(),
+ File = mnesia_lib:dir(Str),
+ file:delete(File),
+ case catch make_initial_backup(Ns, File, Mod) of
+ {ok, _Res} ->
+ case do_install_fallback(File, Mod) of
+ ok ->
+ file:delete(File),
+ ok;
+ {error, Reason} ->
+ {error, Reason}
+ end;
+ {error, Reason} ->
+ {error, Reason}
+ end
+ end
+ end;
+ {error, Reason} ->
+ {error, Reason}
+ end;
+create_schema(_Ns, {error, Reason}) ->
+ {error, Reason};
+create_schema(_Ns, Reason) ->
+ {error, Reason}.
+
+mk_str() ->
+ Now = [integer_to_list(I) || I <- tuple_to_list(now())],
+ lists:concat([node()] ++ Now ++ ".TMP").
+
+make_initial_backup(Ns, Opaque, Mod) ->
+ Schema = [{schema, schema, mnesia_schema:get_initial_schema(disc_copies, Ns)}],
+ O2 = do_apply(Mod, open_write, [Opaque], Opaque),
+ O3 = do_apply(Mod, write, [O2, [mnesia_log:backup_log_header()]], O2),
+ O4 = do_apply(Mod, write, [O3, Schema], O3),
+ O5 = do_apply(Mod, commit_write, [O4], O4),
+ {ok, O5}.
+
+do_apply(_, write, [_, Items], Opaque) when Items =:= [] ->
+ Opaque;
+do_apply(Mod, What, Args, _Opaque) ->
+ case catch apply(Mod, What, Args) of
+ {ok, Opaque2} -> Opaque2;
+ {error, Reason} -> throw({error, Reason});
+ {'EXIT', Reason} -> throw({error, {'EXIT', Reason}})
+ end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Restore
+
+%% Restore schema and possibly other tables from a backup
+%% and replicate them to the necessary nodes
+%% Requires that old schemas has been deleted
+%% Returns ok | {error, Reason}
+install_fallback(Opaque) ->
+ install_fallback(Opaque, []).
+
+install_fallback(Opaque, Args) ->
+ %% Ensure that we access the intended Mnesia
+ %% directory. This function may not be called
+ %% during startup since it will cause the
+ %% application_controller to get into deadlock
+ case mnesia_lib:ensure_loaded(?APPLICATION) of
+ ok ->
+ do_install_fallback(Opaque, Args);
+ {error, Reason} ->
+ {error, Reason}
+ end.
+
+do_install_fallback(Opaque, Mod) when is_atom(Mod) ->
+ do_install_fallback(Opaque, [{module, Mod}]);
+do_install_fallback(Opaque, Args) when is_list(Args) ->
+ case check_fallback_args(Args, #fallback_args{opaque = Opaque}) of
+ {ok, FA} ->
+ do_install_fallback(FA);
+ {error, Reason} ->
+ {error, Reason}
+ end;
+do_install_fallback(_Opaque, Args) ->
+ {error, {badarg, Args}}.
+
+check_fallback_args([Arg | Tail], FA) ->
+ case catch check_fallback_arg_type(Arg, FA) of
+ {'EXIT', _Reason} ->
+ {error, {badarg, Arg}};
+ FA2 ->
+ check_fallback_args(Tail, FA2)
+ end;
+check_fallback_args([], FA) ->
+ {ok, FA}.
+
+check_fallback_arg_type(Arg, FA) ->
+ case Arg of
+ {scope, global} ->
+ FA#fallback_args{scope = global};
+ {scope, local} ->
+ FA#fallback_args{scope = local};
+ {module, Mod} ->
+ Mod2 = mnesia_monitor:do_check_type(backup_module, Mod),
+ FA#fallback_args{module = Mod2};
+ {mnesia_dir, Dir} ->
+ FA#fallback_args{mnesia_dir = Dir,
+ use_default_dir = false};
+ {keep_tables, Tabs} ->
+ atom_list(Tabs),
+ FA#fallback_args{keep_tables = Tabs};
+ {skip_tables, Tabs} ->
+ atom_list(Tabs),
+ FA#fallback_args{skip_tables = Tabs};
+ {default_op, keep_tables} ->
+ FA#fallback_args{default_op = keep_tables};
+ {default_op, skip_tables} ->
+ FA#fallback_args{default_op = skip_tables}
+ end.
+
+atom_list([H | T]) when is_atom(H) ->
+ atom_list(T);
+atom_list([]) ->
+ ok.
+
+do_install_fallback(FA) ->
+ Pid = spawn_link(?MODULE, install_fallback_master, [self(), FA]),
+ Res =
+ receive
+ {'EXIT', Pid, Reason} -> % if appl has trapped exit
+ {error, {'EXIT', Reason}};
+ {Pid, Res2} ->
+ case Res2 of
+ {ok, _} ->
+ ok;
+ {error, Reason} ->
+ {error, {"Cannot install fallback", Reason}}
+ end
+ end,
+ Res.
+
+install_fallback_master(ClientPid, FA) ->
+ process_flag(trap_exit, true),
+ State = {start, FA},
+ Opaque = FA#fallback_args.opaque,
+ Mod = FA#fallback_args.module,
+ Res = (catch iterate(Mod, fun restore_recs/4, Opaque, State)),
+ unlink(ClientPid),
+ ClientPid ! {self(), Res},
+ exit(shutdown).
+
+restore_recs(_, _, _, stop) ->
+ throw({error, "restore_recs already stopped"});
+
+restore_recs(Recs, Header, Schema, {start, FA}) ->
+ %% No records in backup
+ Schema2 = convert_schema(Header#log_header.log_version, Schema),
+ CreateList = lookup_schema(schema, Schema2),
+ case catch mnesia_schema:list2cs(CreateList) of
+ {'EXIT', Reason} ->
+ throw({error, {"Bad schema in restore_recs", Reason}});
+ Cs ->
+ Ns = get_fallback_nodes(FA, Cs#cstruct.disc_copies),
+ global:set_lock({{mnesia_table_lock, schema}, self()}, Ns, infinity),
+ Args = [self(), FA],
+ Pids = [spawn_link(N, ?MODULE, fallback_receiver, Args) || N <- Ns],
+ send_fallback(Pids, {start, Header, Schema2}),
+ Res = restore_recs(Recs, Header, Schema2, Pids),
+ global:del_lock({{mnesia_table_lock, schema}, self()}, Ns),
+ Res
+ end;
+
+restore_recs([], _Header, _Schema, Pids) ->
+ send_fallback(Pids, swap),
+ send_fallback(Pids, stop),
+ stop;
+
+restore_recs(Recs, _, _, Pids) ->
+ send_fallback(Pids, {records, Recs}),
+ Pids.
+
+get_fallback_nodes(FA, Ns) ->
+ This = node(),
+ case lists:member(This, Ns) of
+ true ->
+ case FA#fallback_args.scope of
+ global -> Ns;
+ local -> [This]
+ end;
+ false ->
+ throw({error, {"No disc resident schema on local node", Ns}})
+ end.
+
+send_fallback(Pids, Msg) when is_list(Pids), Pids =/= [] ->
+ lists:foreach(fun(Pid) -> Pid ! {self(), Msg} end, Pids),
+ rec_answers(Pids, []).
+
+rec_answers([], Acc) ->
+ case {lists:keysearch(error, 1, Acc), mnesia_lib:uniq(Acc)} of
+ {{value, {error, Val}}, _} -> throw({error, Val});
+ {_, [SameAnswer]} -> SameAnswer;
+ {_, Other} -> throw({error, {"Different answers", Other}})
+ end;
+rec_answers(Pids, Acc) ->
+ receive
+ {'EXIT', Pid, stopped} ->
+ Pids2 = lists:delete(Pid, Pids),
+ rec_answers(Pids2, [stopped|Acc]);
+ {'EXIT', Pid, Reason} ->
+ Pids2 = lists:delete(Pid, Pids),
+ rec_answers(Pids2, [{error, {'EXIT', Pid, Reason}}|Acc]);
+ {Pid, Reply} ->
+ Pids2 = lists:delete(Pid, Pids),
+ rec_answers(Pids2, [Reply|Acc])
+ end.
+
+fallback_exists() ->
+ Fname = fallback_bup(),
+ fallback_exists(Fname).
+
+fallback_exists(Fname) ->
+ case mnesia_monitor:use_dir() of
+ true ->
+ mnesia_lib:exists(Fname);
+ false ->
+ case ?catch_val(active_fallback) of
+ {'EXIT', _} -> false;
+ Bool -> Bool
+ end
+ end.
+
+fallback_name() -> "FALLBACK.BUP".
+fallback_bup() -> mnesia_lib:dir(fallback_name()).
+
+fallback_tmp_name() -> "FALLBACK.TMP".
+%% fallback_full_tmp_name() -> mnesia_lib:dir(fallback_tmp_name()).
+
+fallback_receiver(Master, FA) ->
+ process_flag(trap_exit, true),
+
+ case catch register(mnesia_fallback, self()) of
+ {'EXIT', _} ->
+ Reason = {already_exists, node()},
+ local_fallback_error(Master, Reason);
+ true ->
+ FA2 = check_fallback_dir(Master, FA),
+ Bup = FA2#fallback_args.fallback_bup,
+ case mnesia_lib:exists(Bup) of
+ true ->
+ Reason2 = {already_exists, node()},
+ local_fallback_error(Master, Reason2);
+ false ->
+ Mod = mnesia_backup,
+ Tmp = FA2#fallback_args.fallback_tmp,
+ R = #restore{mode = replace,
+ bup_module = Mod,
+ bup_data = Tmp},
+ file:delete(Tmp),
+ case catch fallback_receiver_loop(Master, R, FA2, schema) of
+ {error, Reason} ->
+ local_fallback_error(Master, Reason);
+ Other ->
+ exit(Other)
+ end
+ end
+ end.
+
+local_fallback_error(Master, Reason) ->
+ Master ! {self(), {error, Reason}},
+ unlink(Master),
+ exit(Reason).
+
+check_fallback_dir(Master, FA) ->
+ case mnesia:system_info(schema_location) of
+ ram ->
+ Reason = {has_no_disc, node()},
+ local_fallback_error(Master, Reason);
+ _ ->
+ Dir = check_fallback_dir_arg(Master, FA),
+ Bup = filename:join([Dir, fallback_name()]),
+ Tmp = filename:join([Dir, fallback_tmp_name()]),
+ FA#fallback_args{fallback_bup = Bup,
+ fallback_tmp = Tmp,
+ mnesia_dir = Dir}
+ end.
+
+check_fallback_dir_arg(Master, FA) ->
+ case FA#fallback_args.use_default_dir of
+ true ->
+ mnesia_lib:dir();
+ false when FA#fallback_args.scope =:= local ->
+ Dir = FA#fallback_args.mnesia_dir,
+ case catch mnesia_monitor:do_check_type(dir, Dir) of
+ {'EXIT', _R} ->
+ Reason = {badarg, {dir, Dir}, node()},
+ local_fallback_error(Master, Reason);
+ AbsDir->
+ AbsDir
+ end;
+ false when FA#fallback_args.scope =:= global ->
+ Reason = {combine_error, global, dir, node()},
+ local_fallback_error(Master, Reason)
+ end.
+
+fallback_receiver_loop(Master, R, FA, State) ->
+ receive
+ {Master, {start, Header, Schema}} when State =:= schema ->
+ Dir = FA#fallback_args.mnesia_dir,
+ throw_bad_res(ok, mnesia_schema:opt_create_dir(true, Dir)),
+ R2 = safe_apply(R, open_write, [R#restore.bup_data]),
+ R3 = safe_apply(R2, write, [R2#restore.bup_data, [Header]]),
+ BupSchema = [schema2bup(S) || S <- Schema],
+ R4 = safe_apply(R3, write, [R3#restore.bup_data, BupSchema]),
+ Master ! {self(), ok},
+ fallback_receiver_loop(Master, R4, FA, records);
+
+ {Master, {records, Recs}} when State =:= records ->
+ R2 = safe_apply(R, write, [R#restore.bup_data, Recs]),
+ Master ! {self(), ok},
+ fallback_receiver_loop(Master, R2, FA, records);
+
+ {Master, swap} when State =/= schema ->
+ ?eval_debug_fun({?MODULE, fallback_receiver_loop, pre_swap}, []),
+ safe_apply(R, commit_write, [R#restore.bup_data]),
+ Bup = FA#fallback_args.fallback_bup,
+ Tmp = FA#fallback_args.fallback_tmp,
+ throw_bad_res(ok, file:rename(Tmp, Bup)),
+ catch mnesia_lib:set(active_fallback, true),
+ ?eval_debug_fun({?MODULE, fallback_receiver_loop, post_swap}, []),
+ Master ! {self(), ok},
+ fallback_receiver_loop(Master, R, FA, stop);
+
+ {Master, stop} when State =:= stop ->
+ stopped;
+
+ Msg ->
+ safe_apply(R, abort_write, [R#restore.bup_data]),
+ Tmp = FA#fallback_args.fallback_tmp,
+ file:delete(Tmp),
+ throw({error, "Unexpected msg fallback_receiver_loop", Msg})
+ end.
+
+throw_bad_res(Expected, Expected) -> Expected;
+throw_bad_res(_Expected, {error, Actual}) -> throw({error, Actual});
+throw_bad_res(_Expected, Actual) -> throw({error, Actual}).
+
+-record(local_tab, {name,
+ storage_type,
+ open,
+ add,
+ close,
+ swap,
+ record_name,
+ opened}).
+
+tm_fallback_start(IgnoreFallback) ->
+ mnesia_schema:lock_schema(),
+ Res = do_fallback_start(fallback_exists(), IgnoreFallback),
+ mnesia_schema: unlock_schema(),
+ case Res of
+ ok -> ok;
+ {error, Reason} -> exit(Reason)
+ end.
+
+do_fallback_start(false, _IgnoreFallback) ->
+ ok;
+do_fallback_start(true, true) ->
+ verbose("Ignoring fallback at startup, but leaving it active...~n", []),
+ mnesia_lib:set(active_fallback, true),
+ ok;
+do_fallback_start(true, false) ->
+ verbose("Starting from fallback...~n", []),
+
+ BupFile = fallback_bup(),
+ Mod = mnesia_backup,
+ LocalTabs = ?ets_new_table(mnesia_local_tables, [set, public, {keypos, 2}]),
+ case catch iterate(Mod, fun restore_tables/4, BupFile, {start, LocalTabs}) of
+ {ok, _Res} ->
+ catch dets:close(schema),
+ TmpSchema = mnesia_lib:tab2tmp(schema),
+ DatSchema = mnesia_lib:tab2dat(schema),
+ AllLT = ?ets_match_object(LocalTabs, '_'),
+ ?ets_delete_table(LocalTabs),
+ case file:rename(TmpSchema, DatSchema) of
+ ok ->
+ [(LT#local_tab.swap)(LT#local_tab.name, LT) ||
+ LT <- AllLT, LT#local_tab.name =/= schema],
+ file:delete(BupFile),
+ ok;
+ {error, Reason} ->
+ file:delete(TmpSchema),
+ {error, {"Cannot start from fallback. Rename error.", Reason}}
+ end;
+ {error, Reason} ->
+ {error, {"Cannot start from fallback", Reason}};
+ {'EXIT', Reason} ->
+ {error, {"Cannot start from fallback", Reason}}
+ end.
+
+restore_tables(All=[Rec | Recs], Header, Schema, State={local, LocalTabs, LT}) ->
+ Tab = element(1, Rec),
+ if
+ Tab =:= LT#local_tab.name ->
+ Key = element(2, Rec),
+ (LT#local_tab.add)(Tab, Key, Rec, LT),
+ restore_tables(Recs, Header, Schema, State);
+ true ->
+ NewState = {new, LocalTabs},
+ restore_tables(All, Header, Schema, NewState)
+ end;
+restore_tables(All=[Rec | Recs], Header, Schema, {new, LocalTabs}) ->
+ Tab = element(1, Rec),
+ case ?ets_lookup(LocalTabs, Tab) of
+ [] ->
+ State = {not_local, LocalTabs, Tab},
+ restore_tables(Recs, Header, Schema, State);
+ [LT] when is_record(LT, local_tab) ->
+ State = {local, LocalTabs, LT},
+ case LT#local_tab.opened of
+ true -> ignore;
+ false ->
+ (LT#local_tab.open)(Tab, LT),
+ ?ets_insert(LocalTabs,LT#local_tab{opened=true})
+ end,
+ restore_tables(All, Header, Schema, State)
+ end;
+restore_tables(All=[Rec | Recs], Header, Schema, S = {not_local, LocalTabs, PrevTab}) ->
+ Tab = element(1, Rec),
+ if
+ Tab =:= PrevTab ->
+ restore_tables(Recs, Header, Schema, S);
+ true ->
+ State = {new, LocalTabs},
+ restore_tables(All, Header, Schema, State)
+ end;
+restore_tables(Recs, Header, Schema, {start, LocalTabs}) ->
+ Dir = mnesia_lib:dir(),
+ OldDir = filename:join([Dir, "OLD_DIR"]),
+ mnesia_schema:purge_dir(OldDir, []),
+ mnesia_schema:purge_dir(Dir, [fallback_name()]),
+ init_dat_files(Schema, LocalTabs),
+ State = {new, LocalTabs},
+ restore_tables(Recs, Header, Schema, State);
+restore_tables([], _Header, _Schema, State) ->
+ State.
+
+%% Creates all neccessary dat files and inserts
+%% the table definitions in the schema table
+%%
+%% Returns a list of local_tab tuples for all local tables
+init_dat_files(Schema, LocalTabs) ->
+ TmpFile = mnesia_lib:tab2tmp(schema),
+ Args = [{file, TmpFile}, {keypos, 2}, {type, set}],
+ case dets:open_file(schema, Args) of % Assume schema lock
+ {ok, _} ->
+ create_dat_files(Schema, LocalTabs),
+ ok = dets:close(schema),
+ LocalTab = #local_tab{name = schema,
+ storage_type = disc_copies,
+ open = undefined,
+ add = undefined,
+ close = undefined,
+ swap = undefined,
+ record_name = schema,
+ opened = false},
+ ?ets_insert(LocalTabs, LocalTab);
+ {error, Reason} ->
+ throw({error, {"Cannot open file", schema, Args, Reason}})
+ end.
+
+create_dat_files([{schema, schema, TabDef} | Tail], LocalTabs) ->
+ ok = dets:insert(schema, {schema, schema, TabDef}),
+ create_dat_files(Tail, LocalTabs);
+create_dat_files([{schema, Tab, TabDef} | Tail], LocalTabs) ->
+ TmpFile = mnesia_lib:tab2tmp(Tab),
+ DatFile = mnesia_lib:tab2dat(Tab),
+ DclFile = mnesia_lib:tab2dcl(Tab),
+ DcdFile = mnesia_lib:tab2dcd(Tab),
+ Expunge = fun() ->
+ file:delete(DatFile),
+ file:delete(DclFile),
+ file:delete(DcdFile)
+ end,
+
+ mnesia_lib:dets_sync_close(Tab),
+ file:delete(TmpFile),
+ Cs = mnesia_schema:list2cs(TabDef),
+ ok = dets:insert(schema, {schema, Tab, TabDef}),
+ RecName = Cs#cstruct.record_name,
+ Storage = mnesia_lib:cs_to_storage_type(node(), Cs),
+ if
+ Storage =:= unknown ->
+ ok = dets:delete(schema, {schema, Tab}),
+ create_dat_files(Tail, LocalTabs);
+ Storage =:= disc_only_copies ->
+ Args = [{file, TmpFile}, {keypos, 2},
+ {type, mnesia_lib:disk_type(Tab, Cs#cstruct.type)}],
+ Open = fun(T, LT) when T =:= LT#local_tab.name ->
+ case mnesia_lib:dets_sync_open(T, Args) of
+ {ok, _} ->
+ ok;
+ {error, Reason} ->
+ throw({error, {"Cannot open file", T, Args, Reason}})
+ end
+ end,
+ Add = fun(T, Key, Rec, LT) when T =:= LT#local_tab.name ->
+ case Rec of
+ {_T, Key} ->
+ ok = dets:delete(T, Key);
+ (Rec) when T =:= RecName ->
+ ok = dets:insert(Tab, Rec);
+ (Rec) ->
+ Rec2 = setelement(1, Rec, RecName),
+ ok = dets:insert(T, Rec2)
+ end
+ end,
+ Close = fun(T, LT) when T =:= LT#local_tab.name ->
+ mnesia_lib:dets_sync_close(T)
+ end,
+ Swap = fun(T, LT) when T =:= LT#local_tab.name ->
+ Expunge(),
+ case LT#local_tab.opened of
+ true ->
+ Close(T,LT);
+ false ->
+ Open(T,LT),
+ Close(T,LT)
+ end,
+ case file:rename(TmpFile, DatFile) of
+ ok ->
+ ok;
+ {error, Reason} ->
+ mnesia_lib:fatal("Cannot rename file ~p -> ~p: ~p~n",
+ [TmpFile, DatFile, Reason])
+ end
+ end,
+ LocalTab = #local_tab{name = Tab,
+ storage_type = Storage,
+ open = Open,
+ add = Add,
+ close = Close,
+ swap = Swap,
+ record_name = RecName,
+ opened = false},
+ ?ets_insert(LocalTabs, LocalTab),
+ create_dat_files(Tail, LocalTabs);
+ Storage =:= ram_copies; Storage =:= disc_copies ->
+ Open = fun(T, LT) when T =:= LT#local_tab.name ->
+ mnesia_log:open_log({?MODULE, T},
+ mnesia_log:dcl_log_header(),
+ TmpFile,
+ false,
+ false,
+ read_write)
+ end,
+ Add = fun(T, Key, Rec, LT) when T =:= LT#local_tab.name ->
+ Log = {?MODULE, T},
+ case Rec of
+ {_T, Key} ->
+ mnesia_log:append(Log, {{T, Key}, {T, Key}, delete});
+ (Rec) when T =:= RecName ->
+ mnesia_log:append(Log, {{T, Key}, Rec, write});
+ (Rec) ->
+ Rec2 = setelement(1, Rec, RecName),
+ mnesia_log:append(Log, {{T, Key}, Rec2, write})
+ end
+ end,
+ Close = fun(T, LT) when T =:= LT#local_tab.name ->
+ mnesia_log:close_log({?MODULE, T})
+ end,
+ Swap = fun(T, LT) when T =:= LT#local_tab.name ->
+ Expunge(),
+ if
+ Storage =:= ram_copies, LT#local_tab.opened =:= false ->
+ ok;
+ true ->
+ Log = mnesia_log:open_log(fallback_tab,
+ mnesia_log:dcd_log_header(),
+ DcdFile,
+ false),
+ mnesia_log:close_log(Log),
+ case LT#local_tab.opened of
+ true ->
+ Close(T,LT);
+ false ->
+ Open(T,LT),
+ Close(T,LT)
+ end,
+ case file:rename(TmpFile, DclFile) of
+ ok ->
+ ok;
+ {error, Reason} ->
+ mnesia_lib:fatal("Cannot rename file ~p -> ~p: ~p~n",
+ [TmpFile, DclFile, Reason])
+ end
+ end
+ end,
+ LocalTab = #local_tab{name = Tab,
+ storage_type = Storage,
+ open = Open,
+ add = Add,
+ close = Close,
+ swap = Swap,
+ record_name = RecName,
+ opened = false
+ },
+ ?ets_insert(LocalTabs, LocalTab),
+ create_dat_files(Tail, LocalTabs)
+ end;
+create_dat_files([{schema, Tab} | Tail], LocalTabs) ->
+ ?ets_delete(LocalTabs, Tab),
+ ok = dets:delete(schema, {schema, Tab}),
+ TmpFile = mnesia_lib:tab2tmp(Tab),
+ mnesia_lib:dets_sync_close(Tab),
+ file:delete(TmpFile),
+ create_dat_files(Tail, LocalTabs);
+create_dat_files([], _LocalTabs) ->
+ ok.
+
+uninstall_fallback() ->
+ uninstall_fallback([{scope, global}]).
+
+uninstall_fallback(Args) ->
+ case check_fallback_args(Args, #fallback_args{}) of
+ {ok, FA} ->
+ do_uninstall_fallback(FA);
+ {error, Reason} ->
+ {error, Reason}
+ end.
+
+do_uninstall_fallback(FA) ->
+ %% Ensure that we access the intended Mnesia
+ %% directory. This function may not be called
+ %% during startup since it will cause the
+ %% application_controller to get into deadlock
+ case mnesia_lib:ensure_loaded(?APPLICATION) of
+ ok ->
+ Pid = spawn_link(?MODULE, uninstall_fallback_master, [self(), FA]),
+ receive
+ {'EXIT', Pid, Reason} -> % if appl has trapped exit
+ {error, {'EXIT', Reason}};
+ {Pid, Res} ->
+ Res
+ end;
+ {error, Reason} ->
+ {error, Reason}
+ end.
+
+uninstall_fallback_master(ClientPid, FA) ->
+ process_flag(trap_exit, true),
+
+ FA2 = check_fallback_dir(ClientPid, FA), % May exit
+ Bup = FA2#fallback_args.fallback_bup,
+ case fallback_to_schema(Bup) of
+ {ok, fallback, List} ->
+ Cs = mnesia_schema:list2cs(List),
+ case catch get_fallback_nodes(FA, Cs#cstruct.disc_copies) of
+ Ns when is_list(Ns) ->
+ do_uninstall(ClientPid, Ns, FA);
+ {error, Reason} ->
+ local_fallback_error(ClientPid, Reason)
+ end;
+ {error, Reason} ->
+ local_fallback_error(ClientPid, Reason)
+ end.
+
+do_uninstall(ClientPid, Ns, FA) ->
+ Args = [self(), FA],
+ global:set_lock({{mnesia_table_lock, schema}, self()}, Ns, infinity),
+ Pids = [spawn_link(N, ?MODULE, local_uninstall_fallback, Args) || N <- Ns],
+ Res = do_uninstall(ClientPid, Pids, [], [], ok),
+ global:del_lock({{mnesia_table_lock, schema}, self()}, Ns),
+ ClientPid ! {self(), Res},
+ unlink(ClientPid),
+ exit(shutdown).
+
+do_uninstall(ClientPid, [Pid | Pids], GoodPids, BadNodes, Res) ->
+ receive
+ %% {'EXIT', ClientPid, _} ->
+ %% client_exit;
+ {'EXIT', Pid, Reason} ->
+ BadNode = node(Pid),
+ BadRes = {error, {"Uninstall fallback", BadNode, Reason}},
+ do_uninstall(ClientPid, Pids, GoodPids, [BadNode | BadNodes], BadRes);
+ {Pid, {error, Reason}} ->
+ BadNode = node(Pid),
+ BadRes = {error, {"Uninstall fallback", BadNode, Reason}},
+ do_uninstall(ClientPid, Pids, GoodPids, [BadNode | BadNodes], BadRes);
+ {Pid, started} ->
+ do_uninstall(ClientPid, Pids, [Pid | GoodPids], BadNodes, Res)
+ end;
+do_uninstall(ClientPid, [], GoodPids, [], ok) ->
+ lists:foreach(fun(Pid) -> Pid ! {self(), do_uninstall} end, GoodPids),
+ rec_uninstall(ClientPid, GoodPids, ok);
+do_uninstall(_ClientPid, [], GoodPids, BadNodes, BadRes) ->
+ lists:foreach(fun(Pid) -> exit(Pid, shutdown) end, GoodPids),
+ {error, {node_not_running, BadNodes, BadRes}}.
+
+local_uninstall_fallback(Master, FA) ->
+ %% Don't trap exit
+
+ register(mnesia_fallback, self()), % May exit
+ FA2 = check_fallback_dir(Master, FA), % May exit
+ Master ! {self(), started},
+
+ receive
+ {Master, do_uninstall} ->
+ ?eval_debug_fun({?MODULE, uninstall_fallback2, pre_delete}, []),
+ catch mnesia_lib:set(active_fallback, false),
+ Tmp = FA2#fallback_args.fallback_tmp,
+ Bup = FA2#fallback_args.fallback_bup,
+ file:delete(Tmp),
+ Res =
+ case fallback_exists(Bup) of
+ true -> file:delete(Bup);
+ false -> ok
+ end,
+ ?eval_debug_fun({?MODULE, uninstall_fallback2, post_delete}, []),
+ Master ! {self(), Res},
+ unlink(Master),
+ exit(normal)
+ end.
+
+rec_uninstall(ClientPid, [Pid | Pids], AccRes) ->
+ receive
+ %% {'EXIT', ClientPid, _} ->
+ %% exit(shutdown);
+ {'EXIT', Pid, R} ->
+ Reason = {node_not_running, {node(Pid), R}},
+ rec_uninstall(ClientPid, Pids, {error, Reason});
+ {Pid, ok} ->
+ rec_uninstall(ClientPid, Pids, AccRes);
+ {Pid, BadRes} ->
+ rec_uninstall(ClientPid, Pids, BadRes)
+ end;
+rec_uninstall(ClientPid, [], Res) ->
+ ClientPid ! {self(), Res},
+ unlink(ClientPid),
+ exit(normal).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Backup traversal
+
+%% Iterate over a backup and produce a new backup.
+%% Fun(BackupItem, Acc) is applied for each BackupItem.
+%%
+%% Valid BackupItems are:
+%%
+%% {schema, Tab} Table to be deleted
+%% {schema, Tab, CreateList} Table to be created, CreateList may be empty
+%% {schema, db_nodes, DbNodes}List of nodes, defaults to [node()] OLD
+%% {schema, version, Version} Schema version OLD
+%% {schema, cookie, Cookie} Unique schema cookie OLD
+%% {Tab, Key} Oid for record to be deleted
+%% Record Record to be inserted.
+%%
+%% The Fun must return a tuple {BackupItems, NewAcc}
+%% where BackupItems is a list of valid BackupItems and
+%% NewAcc is a new accumulator value. Once BackupItems
+%% that not are schema related has been returned, no more schema
+%% items may be returned. The schema related items must always be
+%% first in the backup.
+%%
+%% If TargetMod =:= read_only, no new backup will be created.
+%%
+%% Opening of the source media will be performed by
+%% to SourceMod:open_read(Source)
+%%
+%% Opening of the target media will be performed by
+%% to TargetMod:open_write(Target)
+traverse_backup(Source, Target, Fun, Acc) ->
+ Mod = mnesia_monitor:get_env(backup_module),
+ traverse_backup(Source, Mod, Target, Mod, Fun, Acc).
+
+traverse_backup(Source, SourceMod, Target, TargetMod, Fun, Acc) ->
+ Args = [self(), Source, SourceMod, Target, TargetMod, Fun, Acc],
+ Pid = spawn_link(?MODULE, do_traverse_backup, Args),
+ receive
+ {'EXIT', Pid, Reason} ->
+ {error, {"Backup traversal crashed", Reason}};
+ {iter_done, Pid, Res} ->
+ Res
+ end.
+
+do_traverse_backup(ClientPid, Source, SourceMod, Target, TargetMod, Fun, Acc) ->
+ process_flag(trap_exit, true),
+ Iter =
+ if
+ TargetMod =/= read_only ->
+ case catch do_apply(TargetMod, open_write, [Target], Target) of
+ {error, Error} ->
+ unlink(ClientPid),
+ ClientPid ! {iter_done, self(), {error, Error}},
+ exit(Error);
+ Else -> Else
+ end;
+ true ->
+ ignore
+ end,
+ A = {start, Fun, Acc, TargetMod, Iter},
+ Res =
+ case iterate(SourceMod, fun trav_apply/4, Source, A) of
+ {ok, {iter, _, Acc2, _, Iter2}} when TargetMod =/= read_only ->
+ case catch do_apply(TargetMod, commit_write, [Iter2], Iter2) of
+ {error, Reason} ->
+ {error, Reason};
+ _ ->
+ {ok, Acc2}
+ end;
+ {ok, {iter, _, Acc2, _, _}} ->
+ {ok, Acc2};
+ {error, Reason} when TargetMod =/= read_only->
+ catch do_apply(TargetMod, abort_write, [Iter], Iter),
+ {error, {"Backup traversal failed", Reason}};
+ {error, Reason} ->
+ {error, {"Backup traversal failed", Reason}}
+ end,
+ unlink(ClientPid),
+ ClientPid ! {iter_done, self(), Res}.
+
+trav_apply(Recs, _Header, _Schema, {iter, Fun, Acc, Mod, Iter}) ->
+ {NewRecs, Acc2} = filter_foldl(Fun, Acc, Recs),
+ if
+ Mod =/= read_only, NewRecs =/= [] ->
+ Iter2 = do_apply(Mod, write, [Iter, NewRecs], Iter),
+ {iter, Fun, Acc2, Mod, Iter2};
+ true ->
+ {iter, Fun, Acc2, Mod, Iter}
+ end;
+trav_apply(Recs, Header, Schema, {start, Fun, Acc, Mod, Iter}) ->
+ Iter2 =
+ if
+ Mod =/= read_only ->
+ do_apply(Mod, write, [Iter, [Header]], Iter);
+ true ->
+ Iter
+ end,
+ TravAcc = trav_apply(Schema, Header, Schema, {iter, Fun, Acc, Mod, Iter2}),
+ trav_apply(Recs, Header, Schema, TravAcc).
+
+filter_foldl(Fun, Acc, [Head|Tail]) ->
+ case Fun(Head, Acc) of
+ {HeadItems, HeadAcc} when is_list(HeadItems) ->
+ {TailItems, TailAcc} = filter_foldl(Fun, HeadAcc, Tail),
+ {HeadItems ++ TailItems, TailAcc};
+ Other ->
+ throw({error, {"Fun must return a list", Other}})
+ end;
+filter_foldl(_Fun, Acc, []) ->
+ {[], Acc}.
+