hauleth.dev
Pure Erlang implementation of 9p2000 protocol
filesystem
fs
9p2000
erlang
9p
Fix deadlock in unfs
This was happening when Erlang wanted to read some data about paths
(file info and listing directory) from the FS that was exported by the
same ERTS instance. It happened because of the fact, that there is
single file server shared among all processes, so these calls were
deadlocking.
+66
-28
+18
-6
src/e9p_unfs.erl
+18
-6
src/e9p_unfs.erl
···
19
19
% Create QID and Stat data for given path.
20
20
qid(Root, Path) ->
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21
FullPath = filename:join([Root] ++ Path),
22
-
case file:read_file_info(FullPath, [{time, posix}]) of
22
+
case file:read_file_info(FullPath, [{time, posix}, raw]) of
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{ok, #file_info{type = Type, inode = Inode} = FI} ->
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QID = e9p:make_qid(Type, 0, Inode),
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25
Stat = file_info_to_stat(Path, QID, FI),
···
90
90
-doc false.
91
91
stat({QID, _}, Path, #{root := Root} = State) ->
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FullPath = filename:join([Root] ++ Path),
93
-
case file:read_file_info(FullPath, [{time, posix}]) of
93
+
case file:read_file_info(FullPath, [{time, posix}, raw]) of
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{ok, FileInfo} ->
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Stat = file_info_to_stat(Path, QID, FileInfo),
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{ok, Stat, State};
···
103
103
FileInfo = stat_to_file_info(Stat),
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FullPath = filename:join([Root] ++ Path),
105
105
106
-
case file:write_file_info(FullPath, FileInfo, [{time, posix}]) of
106
+
case file:write_file_info(FullPath, FileInfo, [{time, posix}, raw]) of
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ok -> {ok, State};
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{error, Reason} ->
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{error, io_lib:format("Couldn't write file stat: ~p", [Reason]),
···
115
115
FullPath = filename:join([Root] ++ Path),
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QS = case e9p:is_type(QID, directory) of
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true ->
118
-
{ok, List} = file:list_dir(FullPath),
118
+
% Currently `file` module do not expose raw mode for listing
119
+
% file directory, so we need to call private `prim_file` module
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+
% to access such functionality. Otherwise we can encounter
121
+
% deadlock.
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+
%
123
+
% See: https://github.com/erlang/otp/issues/10593
124
+
{ok, List} = prim_file:list_dir(FullPath),
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{dir, List};
120
126
false ->
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127
{Trunc, Opts} = translate_mode(Mode),
···
141
147
FullPath = filename:join([Root] ++ Path),
142
148
{ok, State} = clunk(FID, State0),
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149
case case e9p:is_type(QID, directory) of
144
-
true -> file:del_dir(FullPath);
145
-
false -> file:delete(FullPath)
150
+
% Currently `file` module do not expose raw mode for listing
151
+
% file directory, so we need to call private `prim_file` module
152
+
% to access such functionality. Otherwise we can encounter
153
+
% deadlock.
154
+
%
155
+
% See: https://github.com/erlang/otp/issues/10593
156
+
true -> prim_file:del_dir(FullPath);
157
+
false -> file:delete(FullPath, [raw])
146
158
end of
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ok -> {ok, State};
148
160
{error, Reason} ->
-17
src/e9p_utils.erl
-17
src/e9p_utils.erl
···
1
-
% SPDX-FileCopyrightText: 2025 Łukasz Niemier <~@hauleth.dev>
2
-
%
3
-
% SPDX-License-Identifier: Apache-2.0
4
-
5
-
-module(e9p_utils).
6
-
7
-
-export([normalize_path/1]).
8
-
9
-
normalize_path(List) -> normalize_path(List, []).
10
-
11
-
normalize_path([], Acc) -> lists:reverse(Acc);
12
-
normalize_path([Dot | Rest], Acc)
13
-
when Dot =:= "." orelse Dot =:= ~"."
14
-
->
15
-
normalize_path(Rest, Acc);
16
-
normalize_path([P | Rest], Acc) ->
17
-
normalize_path(Rest, [P | Acc]).
-1
test/e9p_sysfs_SUITE.erl
-1
test/e9p_sysfs_SUITE.erl
+47
test/e9p_unfs_SUITE.erl
+47
test/e9p_unfs_SUITE.erl
···
1
+
-module(e9p_unfs_SUITE).
2
+
3
+
-compile(export_all).
4
+
5
+
-include_lib("stdlib/include/assert.hrl").
6
+
-include_lib("common_test/include/ct.hrl").
7
+
8
+
all() -> [
9
+
can_list_mount_content
10
+
].
11
+
12
+
init_per_suite(Config) ->
13
+
PrivDir = ?config(priv_dir, Config),
14
+
Source = filename:join(PrivDir, "h"),
15
+
Mount = filename:join(PrivDir, "c"),
16
+
Port = 6666,
17
+
ok = file:make_dir(Source),
18
+
ok = file:make_dir(Mount),
19
+
{ok, PID} = e9p_server:start(Port, {e9p_unfs, #{path => Source}}),
20
+
ct:pal("source: ~s", [Source]),
21
+
ct:pal("mount: ~s", [Mount]),
22
+
Cmd = io_lib:format("9pfs -p ~B localhost ~p",
23
+
[Port, Mount]),
24
+
ct:pal(Cmd),
25
+
_Out = os:cmd(Cmd, #{ exception_on_failure => true }),
26
+
[{fs, PID}, {mount, Mount}, {source, Source} | Config].
27
+
28
+
end_per_suite(Config) ->
29
+
PID = ?config(fs, Config),
30
+
Mount = ?config(mount, Config),
31
+
os:cmd(["umount ", Mount], #{exception_on_failure => true}),
32
+
erlang:exit(PID, normal),
33
+
Config.
34
+
35
+
can_list_mount_content(Config) ->
36
+
Source = ?config(source, Config),
37
+
Mount = ?config(mount, Config),
38
+
file:write_file([Source, "/bar"], "example data"),
39
+
ct:pal(Mount),
40
+
?assertEqual(["bar"], ls(Mount)).
41
+
42
+
%% Helpers
43
+
44
+
ls(Path) ->
45
+
{ok, Files} = file:list_dir(Path),
46
+
% Remove `.fscache` added on macOS
47
+
lists:sort(Files) -- [".fscache"].
+1
-4
test/prop_e9p_msg.erl
+1
-4
test/prop_e9p_msg.erl
···
31
31
qid() ->
32
32
?LET({Type, Version, Path}, {qid_type(), int(4), int(8)},
33
33
e9p:make_qid(Type, Version, Path)).
34
-
qid(Type) ->
35
-
?LET({Version, Path}, {int(4), int(8)},
36
-
e9p:make_qid(Type, Version, Path)).
37
34
38
35
prop_tversion() ->
39
36
?FORALL({Version, MPS}, {bin_str(), int(4)},
···
120
117
enc_dec(#tstat{fid = FID})).
121
118
prop_rstat() ->
122
119
?FORALL({QID, Type, Dev, Mode, Atime, Mtime, Len, Name, Uid, Gid, Muid},
123
-
{qid(), int(2), int(2), int(4), int(4), int(4), int(8), bin_str(), bin_str(),
120
+
{qid(), int(2), int(2), integer(0, 8#777), int(4), int(4), int(8), bin_str(), bin_str(),
124
121
bin_str(), bin_str()},
125
122
begin
126
123
enc_dec(#rstat{