From: Eryu Guan <guaneryu@gmail.com>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: fstests@vger.kernel.org, xfs <linux-xfs@vger.kernel.org>
Subject: Re: [PATCH] generic: test race between appending AIO DIO and fallocate
Date: Sun, 1 Dec 2019 22:28:39 +0800 [thread overview]
Message-ID: <20191201142824.GI8664@desktop> (raw)
In-Reply-To: <20191113024416.GH6235@magnolia>
On Tue, Nov 12, 2019 at 06:44:16PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
>
> Dave Chinner reports[1] that an appending AIO DIO write to the second
> block of a zero-length file and an fallocate request to the first block
> of the same file can race to set isize, with the user-visible end result
> that the file size is set incorrectly to one block long. Write a small
> test to reproduce the results.
>
> [1] https://lore.kernel.org/linux-xfs/20191029100342.GA41131@bfoster/T/
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> .../aio-dio-append-write-fallocate-race.c | 212 ++++++++++++++++++++
I added an entry in .gitignore for it.
> tests/generic/722 | 43 ++++
> tests/generic/722.out | 2
> tests/generic/group | 1
> 4 files changed, 258 insertions(+)
> create mode 100644 src/aio-dio-regress/aio-dio-append-write-fallocate-race.c
> create mode 100755 tests/generic/722
> create mode 100644 tests/generic/722.out
>
> diff --git a/src/aio-dio-regress/aio-dio-append-write-fallocate-race.c b/src/aio-dio-regress/aio-dio-append-write-fallocate-race.c
> new file mode 100644
> index 00000000..091b047d
> --- /dev/null
> +++ b/src/aio-dio-regress/aio-dio-append-write-fallocate-race.c
> @@ -0,0 +1,212 @@
> +// SPDX-License-Identifier: GPL-2.0-or-newer
> +/*
> + * Copyright (c) 2019 Oracle.
> + * All Rights Reserved.
> + *
> + * Race appending aio dio and fallocate to make sure we get the correct file
> + * size afterwards.
> + */
> +#include <stdio.h>
> +#include <pthread.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <unistd.h>
> +#include <string.h>
> +#include <errno.h>
> +#include <libaio.h>
> +#include <stdlib.h>
> +#include <stdbool.h>
> +#include <limits.h>
> +
> +static int fd;
> +static int blocksize;
> +
> +static void *
> +falloc_thread(
> + void *p)
> +{
> + int ret;
> +
> + ret = fallocate(fd, 0, 0, blocksize);
> + if (ret)
> + perror("falloc");
> +
> + return NULL;
> +}
> +
> +static int
> +test(
> + const char *fname,
> + unsigned int iteration,
> + unsigned int *passed)
> +{
> + struct stat sbuf;
> + pthread_t thread;
> + io_context_t ioctx = 0;
> + struct iocb iocb;
> + struct iocb *iocbp = &iocb;
> + struct io_event event;
> + char *buf;
> + bool wait_thread = false;
> + int ret;
> +
> + /* Truncate file, allocate resources for doing IO. */
> + fd = open(fname, O_DIRECT | O_RDWR | O_TRUNC | O_CREAT, 0644);
> + if (fd < 0) {
> + perror(fname);
> + return -1;
> + }
> +
> + ret = fstat(fd, &sbuf);
> + if (ret) {
> + perror(fname);
> + goto out;
> + }
> + blocksize = sbuf.st_blksize;
> +
> + ret = posix_memalign((void **)&buf, blocksize, blocksize);
> + if (ret) {
> + errno = ret;
> + perror("buffer");
> + goto out;
> + }
> + memset(buf, 'X', blocksize);
> + memset(&event, 0, sizeof(event));
> +
> + ret = io_queue_init(1, &ioctx);
> + if (ret) {
> + errno = -ret;
> + perror("io_queue_init");
> + goto out_buf;
> + }
> +
> + /*
> + * Set ourselves up to race fallocate(0..blocksize) with aio dio
> + * pwrite(blocksize..blocksize * 2). This /should/ give us a file
> + * with length (2 * blocksize).
> + */
> + io_prep_pwrite(&iocb, fd, buf, blocksize, blocksize);
> +
> + ret = pthread_create(&thread, NULL, falloc_thread, NULL);
> + if (ret) {
> + errno = ret;
> + perror("pthread");
> + goto out_io;
> + }
> + wait_thread = true;
> +
> + ret = io_submit(ioctx, 1, &iocbp);
> + if (ret != 1) {
> + errno = -ret;
> + perror("io_submit");
> + goto out_join;
> + }
> +
> + ret = io_getevents(ioctx, 1, 1, &event, NULL);
> + if (ret != 1) {
> + errno = -ret;
> + perror("io_getevents");
> + goto out_join;
> + }
> +
> + if (event.res < 0) {
> + errno = -event.res;
> + perror("io_event.res");
> + goto out_join;
> + }
> +
> + if (event.res2 < 0) {
> + errno = -event.res2;
> + perror("io_event.res2");
> + goto out_join;
> + }
> +
> + wait_thread = false;
> + ret = pthread_join(thread, NULL);
> + if (ret) {
> + errno = ret;
> + perror("join");
> + goto out_io;
> + }
> +
> + /* Make sure we actually got a file of size (2 * blocksize). */
> + ret = fstat(fd, &sbuf);
> + if (ret) {
> + perror(fname);
> + goto out_buf;
> + }
> +
> + if (sbuf.st_size != 2 * blocksize) {
> + fprintf(stderr, "[%u]: sbuf.st_size=%llu, expected %llu.\n",
> + iteration,
> + (unsigned long long)sbuf.st_size,
> + (unsigned long long)2 * blocksize);
> + } else {
> + printf("[%u]: passed.\n", iteration);
> + (*passed)++;
> + }
> +
> +out_join:
> + if (wait_thread) {
> + ret = pthread_join(thread, NULL);
> + if (ret) {
> + errno = ret;
> + perror("join");
> + goto out_io;
> + }
> + }
> +out_io:
> + ret = io_queue_release(ioctx);
> + if (ret) {
> + errno = -ret;
> + perror("io_queue_release");
> + }
> +
> +out_buf:
> + free(buf);
> +out:
> + ret = close(fd);
> + fd = -1;
> + if (ret) {
> + perror("close");
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + int ret;
> + long l;
> + unsigned int i;
> + unsigned int passed = 0;
> +
> + if (argc != 3) {
> + printf("Usage: %s filename iterations\n", argv[0]);
> + return 1;
> + }
> +
> + errno = 0;
> + l = strtol(argv[2], NULL, 0);
> + if (errno) {
> + perror(argv[2]);
> + return 1;
> + }
> + if (l < 1 || l > UINT_MAX) {
> + fprintf(stderr, "%ld: must be between 1 and %u.\n",
> + l, UINT_MAX);
> + return 1;
> + }
> +
> + for (i = 0; i < l; i++) {
> + ret = test(argv[1], i, &passed);
> + if (ret)
> + return 1;
> + }
> +
> + printf("pass rate: %u/%u (%.2f%%)\n", passed, i, 100.0 * passed / i);
> +
> + return 0;
> +}
> diff --git a/tests/generic/722 b/tests/generic/722
> new file mode 100755
> index 00000000..937abf36
> --- /dev/null
> +++ b/tests/generic/722
> @@ -0,0 +1,43 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +# Copyright (c) 2019, Oracle and/or its affiliates. All Rights Reserved.
> +#
> +# FS QA Test No. 722
> +#
> +# Race an appending aio dio write to the second block of a file while
> +# simultaneously fallocating to the first block. Make sure that we end up
> +# with a two-block file.
> +
> +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.* $testfile
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +
> +# real QA test starts here
> +_supported_os Linux
> +_supported_fs generic
> +_require_aiodio "aio-dio-append-write-fallocate-race"
> +_require_test
Also added
_require_xfs_io_command "falloc"
Thanks,
Eryu
> +
> +rm -f $seqres.full
> +
> +testfile=$TEST_DIR/test-$seq
> +$AIO_TEST $testfile 100 >> $seqres.full
> +
> +echo Silence is golden.
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/generic/722.out b/tests/generic/722.out
> new file mode 100644
> index 00000000..8621a87d
> --- /dev/null
> +++ b/tests/generic/722.out
> @@ -0,0 +1,2 @@
> +QA output created by 722
> +Silence is golden.
> diff --git a/tests/generic/group b/tests/generic/group
> index e5d0c1da..308f86f2 100644
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -588,3 +588,4 @@
> 583 auto quick encrypt
> 584 auto quick encrypt
> 585 auto rename
> +722 auto quick rw falloc
next prev parent reply other threads:[~2019-12-01 14:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-13 2:44 [PATCH] generic: test race between appending AIO DIO and fallocate Darrick J. Wong
2019-12-01 14:28 ` Eryu Guan [this message]
2019-12-02 16:28 ` Darrick J. Wong
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191201142824.GI8664@desktop \
--to=guaneryu@gmail.com \
--cc=darrick.wong@oracle.com \
--cc=fstests@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).