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Diffstat (limited to 'lib/mnesia/src/mnesia_bup.erl')
| -rw-r--r-- | lib/mnesia/src/mnesia_bup.erl | 1186 |
1 files changed, 1186 insertions, 0 deletions
diff --git a/lib/mnesia/src/mnesia_bup.erl b/lib/mnesia/src/mnesia_bup.erl new file mode 100644 index 0000000000..37a8258d74 --- /dev/null +++ b/lib/mnesia/src/mnesia_bup.erl @@ -0,0 +1,1186 @@ +%% +%% %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}. + |