From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtpng1.m.smailru.net (smtpng1.m.smailru.net [94.100.181.251]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id A36F046970E for ; Sun, 9 Feb 2020 20:37:11 +0300 (MSK) From: Vladislav Shpilevoy Date: Sun, 9 Feb 2020 18:37:09 +0100 Message-Id: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Tarantool-patches] [PATCH 1/1] fio: close unused descriptors automatically List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: tarantool-patches@dev.tarantool.org, korablev@tarantool.org, imun@tarantool.org Fio.open() returned a file descriptor, which was not closed automatically after all its links were nullified. In other words, GC didn't close the descriptor. This was not really useful, because after fio.open() an exception may appear, and user needed to workaround this to manually call fio_object:close(). Also this was not consistent with io.open(). Now fio.open() object closes the descriptor automatically when GCed. Closes #4727 @TarantoolBot document Title: fio descriptor is closed automatically by GC fio.open() returns a descriptor which can be closed manually by calling :close() method, or it will be closed automatically, when it has no references, and GC deletes it. :close() method existed always, auto GC was added just now. --- @ChangeLog - fio descriptors are closed on garbage collection (gh-4727). src/lua/fio.lua | 33 ++++++++++++--- test/app/fio.result | 93 +++++++++++++++++++++++++++++++++++++++++++ test/app/fio.test.lua | 58 +++++++++++++++++++++++++++ 3 files changed, 178 insertions(+), 6 deletions(-) diff --git a/src/lua/fio.lua b/src/lua/fio.lua index 4692e1026..41901904c 100644 --- a/src/lua/fio.lua +++ b/src/lua/fio.lua @@ -141,10 +141,12 @@ end fio_methods.close = function(self) local res, err = internal.close(self.fh) - self.fh = -1 if err ~= nil then return false, err end + ffi.gc(self._gc, nil) + self._gc = nil + self.fh = -1 return res end @@ -160,7 +162,23 @@ fio_methods.stat = function(self) return internal.fstat(self.fh) end -local fio_mt = { __index = fio_methods } +local fio_mt = { + __index = fio_methods, + __serialize = function(obj) + return {fh = obj.fh} + end, +} + +local function fio_wrap(fh) + return setmetatable({ + fh = fh, + _gc = ffi.gc(ffi.new('char[1]'), function() + -- FFI GC can't yield. Internal.close() yields. + -- Collect the garbage later, in a separate fiber. + fiber.create(internal.close, fh) + end) + }, fio_mt) +end fio.open = function(path, flags, mode) local iflag = 0 @@ -202,10 +220,13 @@ fio.open = function(path, flags, mode) if err ~= nil then return nil, err end - - fh = { fh = fh } - setmetatable(fh, fio_mt) - return fh + local ok, res = pcall(fio_wrap, fh) + if not ok then + internal.close(fh) + -- This is either OOM or bad syntax, both require throw. + return error(res) + end + return res end fio.pathjoin = function(...) diff --git a/test/app/fio.result b/test/app/fio.result index f83c43f44..6345ac22e 100644 --- a/test/app/fio.result +++ b/test/app/fio.result @@ -1456,3 +1456,96 @@ fio.mktree('/dev/null/dir') - false - 'Error creating directory /dev/null: File exists' ... +-- +-- gh-4727: fio handler GC. +-- +flags = {'O_CREAT', 'O_RDWR'} +--- +... +mode = {'S_IRWXU'} +--- +... +filename = 'test4727.txt' +--- +... +fh1 = nil +--- +... +fh2 = nil +--- +... +-- Idea of the test is that according to the Open Group standard, +-- open() always returns the smallest available descriptor. This +-- means, that in 'open() + close() + open()' the second open() +-- should return the same value as the first call, if no other +-- threads/fibers managed to interfere. Because of the +-- interference the sequence may need to be called multiple times +-- to catch a couple of equal descriptors. +-- GC function of a fio object creates a new fiber. Give it \ +-- time to execute. \ +test_run:wait_cond(function() \ + collectgarbage('collect') \ + local f = fio.open(filename, flags, mode) \ + fh1 = f.fh \ + f = nil \ + collectgarbage('collect') \ + fiber.yield() \ + f = fio.open(filename, flags, mode) \ + fh2 = f.fh \ + f = nil \ + collectgarbage('collect') \ + fiber.yield() \ + return fh1 == fh2 \ +end) or {fh1, fh2} +--- +- true +... +-- Ensure, that GC does not break anything after explicit close. +-- Idea of the test is the same as in the previous test, but now +-- the second descriptor is used for something. If GC of the first +-- fio object is called even after close(), it would close the +-- same descriptor, already used by the second fio object. And it +-- won't be able to write anything. Or will write, but to a +-- totally different descriptor created by some other +-- fiber/thread. This is why read() is called on the same file +-- afterwards. +f = nil +--- +... +test_run:wait_cond(function() \ + f = fio.open(filename, flags, mode) \ + fh1 = f.fh \ + f:close() \ + f = fio.open(filename, flags, mode) \ + fh2 = f.fh \ + return fh1 == fh2 \ +end) +--- +- true +... +collectgarbage('collect') +--- +- 0 +... +fiber.yield() +--- +... +f:write('test') +--- +- true +... +f:close() +--- +- true +... +f = fio.open(filename, flags, mode) +--- +... +f:read() +--- +- test +... +f:close() +--- +- true +... diff --git a/test/app/fio.test.lua b/test/app/fio.test.lua index 56c957d8a..c726bade6 100644 --- a/test/app/fio.test.lua +++ b/test/app/fio.test.lua @@ -474,3 +474,61 @@ test_run:cmd("clear filter") -- fio.mktree('/dev/null') fio.mktree('/dev/null/dir') + +-- +-- gh-4727: fio handler GC. +-- +flags = {'O_CREAT', 'O_RDWR'} +mode = {'S_IRWXU'} +filename = 'test4727.txt' +fh1 = nil +fh2 = nil +-- Idea of the test is that according to the Open Group standard, +-- open() always returns the smallest available descriptor. This +-- means, that in 'open() + close() + open()' the second open() +-- should return the same value as the first call, if no other +-- threads/fibers managed to interfere. Because of the +-- interference the sequence may need to be called multiple times +-- to catch a couple of equal descriptors. +test_run:wait_cond(function() \ + collectgarbage('collect') \ + local f = fio.open(filename, flags, mode) \ + fh1 = f.fh \ + f = nil \ + collectgarbage('collect') \ +-- GC function of a fio object creates a new fiber. Give it \ +-- time to execute. \ + fiber.yield() \ + f = fio.open(filename, flags, mode) \ + fh2 = f.fh \ + f = nil \ + collectgarbage('collect') \ + fiber.yield() \ + return fh1 == fh2 \ +end) or {fh1, fh2} + +-- Ensure, that GC does not break anything after explicit close. +-- Idea of the test is the same as in the previous test, but now +-- the second descriptor is used for something. If GC of the first +-- fio object is called even after close(), it would close the +-- same descriptor, already used by the second fio object. And it +-- won't be able to write anything. Or will write, but to a +-- totally different descriptor created by some other +-- fiber/thread. This is why read() is called on the same file +-- afterwards. +f = nil +test_run:wait_cond(function() \ + f = fio.open(filename, flags, mode) \ + fh1 = f.fh \ + f:close() \ + f = fio.open(filename, flags, mode) \ + fh2 = f.fh \ + return fh1 == fh2 \ +end) +collectgarbage('collect') +fiber.yield() +f:write('test') +f:close() +f = fio.open(filename, flags, mode) +f:read() +f:close() -- 2.21.1 (Apple Git-122.3)