Re: [PATCH 2/2] xfs: don't update mtime on COW faults
From: Mikulas Patocka
Date: Fri Sep 11 2020 - 12:42:42 EST
On Wed, 9 Sep 2020, Darrick J. Wong wrote:
> On Sat, Sep 05, 2020 at 01:02:33PM -0400, Mikulas Patocka wrote:
> > > >
> >
> > I've written this program that tests it - you can integrate it into your
> > testsuite.
>
> I don't get it. You're a filesystem maintainer too, which means you're
> a regular contributor. Do you:
>
> (a) not use fstests? If you don't, I really hope you use something else
> to QA hpfs.
I don't use xfstests on HPFS. I was testing it just by using it. Now I use
it just a little, but I don't modify it much.
> (b) really think that it's my problem to integrate and submit your
> regression tests for you?
>
> and (c) what do you want me to do with a piece of code that has no
> signoff tag, no copyright, and no license? This is your patch, and
> therefore your responsibility to develop enough of an appropriate
> regression test in a proper form that the rest of us can easily
> determine we have the rights to contribute to it.
If you want a full patch (I copied the script from test 313), I send it
here.
Mikulas
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Subject: [PATCH] check ctime and mtime vs mmap
Check ctime and mtime are not updated on COW faults
and that they are updated on shared faults
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
src/Makefile | 3 +-
src/mmap-timestamp.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++
tests/generic/609 | 40 +++++++++++++++++++++++++++++++++++++
tests/generic/609.out | 2 +
tests/generic/group | 1
5 files changed, 98 insertions(+), 1 deletion(-)
Index: xfstests-dev/src/Makefile
===================================================================
--- xfstests-dev.orig/src/Makefile 2020-09-06 12:38:40.000000000 +0200
+++ xfstests-dev/src/Makefile 2020-09-11 17:39:04.000000000 +0200
@@ -17,7 +17,8 @@ TARGETS = dirstress fill fill2 getpagesi
t_mmap_cow_race t_mmap_fallocate fsync-err t_mmap_write_ro \
t_ext4_dax_journal_corruption t_ext4_dax_inline_corruption \
t_ofd_locks t_mmap_collision mmap-write-concurrent \
- t_get_file_time t_create_short_dirs t_create_long_dirs
+ t_get_file_time t_create_short_dirs t_create_long_dirs \
+ mmap-timestamp
LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
preallo_rw_pattern_writer ftrunc trunc fs_perms testx looptest \
Index: xfstests-dev/src/mmap-timestamp.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ xfstests-dev/src/mmap-timestamp.c 2020-09-11 18:21:40.000000000 +0200
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2020 Red Hat, Inc. All Rights reserved.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#define FILE_NAME argv[1]
+
+static struct stat st1, st2;
+
+int main(int argc, char *argv[])
+{
+ int h, r;
+ char *map;
+ unlink(FILE_NAME);
+ h = creat(FILE_NAME, 0600);
+ if (h == -1) perror("creat"), exit(1);
+ r = write(h, "x", 1);
+ if (r != 1) perror("write"), exit(1);
+ if (close(h)) perror("close"), exit(1);
+ h = open(FILE_NAME, O_RDWR);
+ if (h == -1) perror("open"), exit(1);
+
+ map = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_PRIVATE, h, 0);
+ if (map == MAP_FAILED) perror("mmap"), exit(1);
+ if (fstat(h, &st1)) perror("fstat"), exit(1);
+ sleep(2);
+ *map = 'y';
+ if (fstat(h, &st2)) perror("fstat"), exit(1);
+ if (st1.st_mtime != st2.st_mtime) fprintf(stderr, "BUG: COW fault changed mtime!\n"), exit(1);
+ if (st1.st_ctime != st2.st_ctime) fprintf(stderr, "BUG: COW fault changed ctime!\n"), exit(1);
+ if (munmap(map, 4096)) perror("munmap"), exit(1);
+
+ map = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, h, 0);
+ if (map == MAP_FAILED) perror("mmap"), exit(1);
+ if (fstat(h, &st1)) perror("fstat"), exit(1);
+ sleep(2);
+ *map = 'z';
+ if (msync(map, 4096, MS_SYNC)) perror("msync"), exit(1);
+ if (fstat(h, &st2)) perror("fstat"), exit(1);
+ if (st1.st_mtime == st2.st_mtime) fprintf(stderr, "BUG: Shared fault did not change mtime!\n"), exit(1);
+ if (st1.st_ctime == st2.st_ctime) fprintf(stderr, "BUG: Shared fault did not change ctime!\n"), exit(1);
+ if (munmap(map, 4096)) perror("munmap"), exit(1);
+
+ if (close(h)) perror("close"), exit(1);
+ if (unlink(FILE_NAME)) perror("unlink"), exit(1);
+ return 0;
+}
Index: xfstests-dev/tests/generic/609
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ xfstests-dev/tests/generic/609 2020-09-11 18:30:30.000000000 +0200
@@ -0,0 +1,40 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020 Red Hat, Inc. All Rights Reserved.
+#
+# FS QA Test No. 609
+#
+# Check ctime and mtime are not updated on COW faults
+# and that they are updated on shared faults
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+status=1 # failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+ cd /
+ rm -f $testfile
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# real QA test starts here
+_supported_fs generic
+_supported_os Linux
+_require_test
+
+testfile=$TEST_DIR/testfile.$seq
+
+echo "Silence is golden"
+
+$here/src/mmap-timestamp $testfile 2>&1
+
+status=0
+exit
Index: xfstests-dev/tests/generic/609.out
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ xfstests-dev/tests/generic/609.out 2020-09-11 18:24:24.000000000 +0200
@@ -0,0 +1,2 @@
+QA output created by 609
+Silence is golden
Index: xfstests-dev/tests/generic/group
===================================================================
--- xfstests-dev.orig/tests/generic/group 2020-09-06 12:38:40.000000000 +0200
+++ xfstests-dev/tests/generic/group 2020-09-11 18:25:09.000000000 +0200
@@ -611,3 +611,4 @@
606 auto attr quick dax
607 auto attr quick dax
608 auto attr quick dax
+609 auto quick