Original report: https://lkml.org/lkml/2014/10/8/545 perform AIO-DIO and fcntl(F_SETFL) concurently Unaligned AIO likely result in synchronization which makes racewindow wider. changes from v2->v3 - Copyright fixes according to Dave's comments changes from v1->v2 - Properly reuse aio context Signed-off-by: Dmitry Monakhov <dmonakhov@xxxxxxxxxx> --- src/aio-dio-regress/aio-dio-fcntl-race.c | 148 ++++++++++++++++++++++++++++++ tests/generic/035 | 50 ++++++++++ tests/generic/035.out | 2 + tests/generic/group | 2 + 4 files changed, 202 insertions(+), 0 deletions(-) create mode 100644 src/aio-dio-regress/aio-dio-fcntl-race.c create mode 100755 tests/generic/035 create mode 100644 tests/generic/035.out diff --git a/src/aio-dio-regress/aio-dio-fcntl-race.c b/src/aio-dio-regress/aio-dio-fcntl-race.c new file mode 100644 index 0000000..e1c8998 --- /dev/null +++ b/src/aio-dio-regress/aio-dio-fcntl-race.c @@ -0,0 +1,148 @@ +/* + * Perform aio writes to file and toggle O_DIRECT flag concurrently + * this may trigger race between file->f_flags read and modification + * unuligned aio allow to makes race window wider. + * Regression test for https://lkml.org/lkml/2014/10/8/545 + * + * Copyright (c) 2014 Dmitry Monakhov. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ +#include <sys/stat.h> +#include <sys/types.h> +#include <errno.h> +#include <fcntl.h> +#include <unistd.h> +#include <libaio.h> +#include <stdio.h> +#include <stdlib.h> +#include <time.h> +#include <sys/time.h> +#include <sys/types.h> +#include <sys/wait.h> + +#define BUF_SIZE 512 +#define LOOP_SECONDS 10 + + +static int do_aio_loop(int fd, void *buf) +{ + int err, ret; + struct io_context *ctx = NULL; + struct io_event ev; + struct iocb iocb, *iocbs[] = { &iocb }; + struct timeval start, now, delta = { 0, 0 }; + + ret = 0; + err = io_setup(1, &ctx); + if (err) { + fprintf(stderr, "error %s during %s\n", + strerror(-err), "io_setup" ); + return 1; + } + while (1) { + io_prep_pwrite(&iocb, fd, buf, BUF_SIZE, BUF_SIZE); + err = io_submit(ctx, 1, iocbs); + if (err != 1) { + fprintf(stderr, "error %s during %s\n", + strerror(-err), + "io_submit"); + ret = 1; + break; + } + err = io_getevents(ctx, 1, 1, &ev, NULL); + if (err != 1) { + fprintf(stderr, "error %s during %s\n", + strerror(-err), + "io_getevents"); + ret = 1; + break; + } + gettimeofday(&now, NULL); + timersub(&now, &start, &delta); + if (delta.tv_sec >= LOOP_SECONDS) + break; + } + io_destroy(ctx); + return ret; +} + +int main(int argc, char **argv) +{ + int flags, fd; + int pid1, pid2 = 0; + int ret1, ret = 0; + + if (argc != 2){ + printf("Usage %s fname\n", argv[0]); + return 1; + } + fd = open(argv[1], O_CREAT | O_TRUNC | O_RDWR, 0600); + if (fd < 0) + return 1; + + pid1 = fork(); + if (pid1 < 0) + return 1; + + if (pid1 == 0) { + struct timeval start, now, delta = { 0, 0 }; + + gettimeofday(&start, NULL); + + /* child: toggle O_DIRECT*/ + flags = fcntl(fd, F_GETFL); + while (1) { + ret = fcntl(fd, F_SETFL, flags | O_DIRECT); + if (ret) + return ret; + ret = fcntl(fd, F_SETFL, flags); + if (ret) + return ret; + + gettimeofday(&now, NULL); + timersub(&now, &start, &delta); + if (delta.tv_sec >= LOOP_SECONDS) + break; + } + } else { + /* parent: AIO */ + void *buf; + posix_memalign(&buf, BUF_SIZE, BUF_SIZE); + /* Two tasks which performs unaligned aio will be serialized + which maks race window wider */ + pid2 = fork(); + if (pid2 < 0) + goto out; + else if (pid2 > 0) + printf("All tasks are spawned\n"); + + ret = do_aio_loop(fd, buf); + } +out: + /* Parent wait for all others */ + if (pid2 > 0){ + waitpid(pid1, &ret1, 0); + if (!ret) + ret = ret1; + waitpid(pid2, &ret1, 0); + } else { + waitpid(pid1, &ret1, 0); + } + if (!ret) + ret = ret1; + + return ret; +} diff --git a/tests/generic/035 b/tests/generic/035 new file mode 100755 index 0000000..51b3491 --- /dev/null +++ b/tests/generic/035 @@ -0,0 +1,50 @@ +#! /bin/bash +# FS QA Test No. 035 +# +# Run aio-dio-fcntl-race - test aio write race with O_DIRECT toggle +# +#----------------------------------------------------------------------- +# Copyright (c) 2014 Dmitry Monakhov. All Rights Reserved. +# +# This program is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public License as +# published by the Free Software Foundation. +# +# This program is distributed in the hope that it would be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write the Free Software Foundation, +# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +#----------------------------------------------------------------------- + +seq=`basename $0` +seqres=$RESULT_DIR/$seq +echo "QA output created by $seq" + +here=`pwd` +tmp=/tmp/$$ +status=1 # failure is the default! +trap "_cleanup; exit \$status" 0 1 2 3 15 + +_cleanup() +{ + cd / + rm -f $tmp.* +} + +# get standard environment, filters and checks +. ./common/rc +. ./common/filter + +# real QA test starts here + +_supported_fs generic +_supported_os Linux +_require_test + +_run_aiodio aio-dio-fcntl-race + +exit $status diff --git a/tests/generic/035.out b/tests/generic/035.out new file mode 100644 index 0000000..f730e2f --- /dev/null +++ b/tests/generic/035.out @@ -0,0 +1,2 @@ +QA output created by 035 +All tasks are spawned diff --git a/tests/generic/group b/tests/generic/group index 799bfd8..419379d 100644 --- a/tests/generic/group +++ b/tests/generic/group @@ -37,6 +37,7 @@ 032 auto quick rw 033 auto quick rw 034 auto quick metadata log +035 auto quick aio rw stress 053 acl repair auto quick 062 attr udf auto quick 068 other auto freeze dangerous stress @@ -151,3 +152,4 @@ 323 auto aio stress 324 auto fsr quick 325 auto quick data log +326 auto quick aio rw stress -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
