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Date:   Fri, 4 Jun 2021 13:12:06 -0700
From:   Leah Rumancik <leah.rumancik@gmail.com>
To:     "Darrick J. Wong" <djwong@kernel.org>
Cc:     fstests@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [v2] ext4/310: test journal checkpoint ioctl
Message-ID: <YLqJFhTpBfzOjdj5@google.com>
References: <20210602221704.2312894-1-leah.rumancik@gmail.com>
 <20210603013437.GA26324@locust>
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On Wed, Jun 02, 2021 at 06:34:37PM -0700, Darrick J. Wong wrote:
> Nit: the subject line still needs "PATCH", e.g.
> 
> [PATCH v2] ext4/310: test journal checkpoint ioctl
> 
> On Wed, Jun 02, 2021 at 10:17:04PM +0000, Leah Rumancik wrote:
> > Test for commit "ext4: add ioctl EXT4_IOC_CHECKPOINT". Tests journal
> > checkpointing and journal erasing via EXT4_IOC_CHECKPOINT with flag
> > EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT set.
> > 
> > Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
> > ---
> >  .gitignore               |   1 +
> >  src/Makefile             |   3 +-
> >  src/checkpoint_journal.c |  95 ++++++++++++++++++++++++++++++++
> >  tests/ext4/310           | 115 +++++++++++++++++++++++++++++++++++++++
> >  tests/ext4/310.out       |   2 +
> >  tests/ext4/group         |   1 +
> >  6 files changed, 216 insertions(+), 1 deletion(-)
> >  create mode 100644 src/checkpoint_journal.c
> >  create mode 100755 tests/ext4/310
> >  create mode 100644 tests/ext4/310.out
> > 
> > diff --git a/.gitignore b/.gitignore
> > index 4cc9c807..cb7e17bf 100644
> > --- a/.gitignore
> > +++ b/.gitignore
> > @@ -182,6 +182,7 @@
> >  /src/idmapped-mounts/mount-idmapped
> >  /src/log-writes/replay-log
> >  /src/perf/*.pyc
> > +/src/checkpoint_journal
> >  
> >  # Symlinked files
> >  /tests/generic/035.out
> > diff --git a/src/Makefile b/src/Makefile
> > index cc0b9579..e0e7006b 100644
> > --- a/src/Makefile
> > +++ b/src/Makefile
> > @@ -17,7 +17,8 @@ TARGETS = dirstress fill fill2 getpagesize holes lstat64 \
> >  	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_enospc
> > +	t_get_file_time t_create_short_dirs t_create_long_dirs t_enospc \
> > +	checkpoint_journal
> >  
> >  LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
> >  	preallo_rw_pattern_writer ftrunc trunc fs_perms testx looptest \
> > diff --git a/src/checkpoint_journal.c b/src/checkpoint_journal.c
> > new file mode 100644
> > index 00000000..0347e0c0
> > --- /dev/null
> > +++ b/src/checkpoint_journal.c
> > @@ -0,0 +1,95 @@
> > +#include <sys/ioctl.h>
> 
> New file needs a SPDX header.
> 
> > +#include <fcntl.h>
> > +#include <stdlib.h>
> > +#include <stdio.h>
> > +#include <unistd.h>
> > +#include <errno.h>
> > +#include <string.h>
> > +#include <linux/fs.h>
> > +#include <getopt.h>
> > +
> > +/*
> > + * checkpoint_journal.c
> > + *
> > + * Flush journal log and checkpoint journal for ext4 file system and
> > + * optionally, issue discard or zeroout for the journal log blocks.
> > + *
> > + * Arguments:
> > + * 1) mount point for device
> > + * 2) flags (optional)
> > + *	set --erase=discard to enable discarding journal blocks
> > + *	set --erase=zeroout to enable zero-filling journal blocks
> > + *	set --dry-run flag to only perform input checking
> > + */
> > +
> > +#if defined(__linux__) && !defined(EXT4_IOC_CHECKPOINT)
> > +#define EXT4_IOC_CHECKPOINT	_IOW('f', 43, __u32)
> > +#endif
> > +
> > +
> > +#if defined(__linux__) && !defined(EXT4_IOC_CHECKPOINT_FLAG_DISCARD)
> > +#define EXT4_IOC_CHECKPOINT_FLAG_DISCARD		1
> > +#define EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT		2
> > +#define EXT4_IOC_CHECKPOINT_FLAG_DRY_RUN		4
> > +#endif
> 
> fstests doesn't support anything other than Linux.
> 
> > +
> > +
> > +int main(int argc, char** argv) {
> > +	int fd, c, ret = 0, option_index = 0;
> > +	char* rpath;
> > +	unsigned int flags = 0;
> > +
> > +	static struct option long_options[] =
> > +	{
> > +		{"dry-run", no_argument, 0, 'd'},
> > +		{"erase", required_argument, 0, 'e'},
> > +		{0, 0, 0, 0}
> > +	};
> > +
> > +	/* get optional flags */
> > +	while ((c = getopt_long(argc, argv, "de:", long_options,
> > +				&option_index)) != -1) {
> > +		switch (c) {
> > +		case 'd':
> > +			flags |= EXT4_IOC_CHECKPOINT_FLAG_DRY_RUN;
> > +			break;
> > +		case 'e':
> > +			if (strcmp(optarg, "discard") == 0) {
> > +				flags |= EXT4_IOC_CHECKPOINT_FLAG_DISCARD;
> > +			} else if (strcmp(optarg, "zeroout") == 0) {
> > +				flags |= EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT;
> > +			} else {
> > +				fprintf(stderr, "Error: invalid erase option\n");
> > +				return 1;
> > +			}
> > +			break;
> > +		default:
> > +			return 1;
> > +		}
> > +	}
> > +
> > +	if (optind != argc - 1) {
> > +		fprintf(stderr, "Error: invalid number of arguments\n");
> > +		return 1;
> > +	}
> > +
> > +	/* get fd to file system */
> > +	rpath = realpath(argv[optind], NULL);
> > +	fd = open(rpath, O_RDONLY);
> > +	free(rpath);
> > +
> > +	if (fd == -1) {
> > +		fprintf(stderr, "Error: unable to open device %s: %s\n",
> > +			argv[optind], strerror(errno));
> > +		return 1;
> > +	}
> > +
> > +	ret = ioctl(fd, EXT4_IOC_CHECKPOINT, &flags);
> > +
> > +	if (ret)
> > +		fprintf(stderr, "checkpoint ioctl returned error: %s\n", strerror(errno));
> > +
> > +	close(fd);
> > +	return ret;
> > +}
> > +
> > diff --git a/tests/ext4/310 b/tests/ext4/310
> > new file mode 100755
> > index 00000000..dd30c782
> > --- /dev/null
> > +++ b/tests/ext4/310
> > @@ -0,0 +1,115 @@
> > +#!/bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (c) 2021 Google, Inc. All Rights Reserved.
> > +#
> > +# FS QA Test No. 310
> > +#
> > +# Test checkpoint and zeroout of journal via ioctl EXT4_IOC_CHECKPOINT
> > +#
> > +
> > +seq=`basename $0`
> > +seqres=$RESULT_DIR/$seq
> > +echo "QA output created by $seq"
> > +
> > +status=1       # failure is the default!
> > +
> > +# get standard environment, filters and checks
> > +. ./common/rc
> > +. ./common/filter
> > +
> > +# remove previous $seqres.full before test
> > +rm -f $seqres.full
> > +
> > +# real QA test starts here
> > +_supported_fs ext4
> > +
> > +_require_scratch
> > +_require_command "$DEBUGFS_PROG" debugfs
> > +
> > +checkpoint_journal=$here/src/checkpoint_journal
> > +_require_test_program "checkpoint_journal"
> > +
> > +# convert output from stat<journal_inode> to list of block numbers
> > +get_journal_extents() {
> > +	inode_info=$($DEBUGFS_PROG $SCRATCH_DEV -R "stat <8>" 2>> $seqres.full)
> > +	echo -e "\nJournal info:" >> $seqres.full
> > +	echo "$inode_info" >> $seqres.full
> > +
> > +	extents_line=$(echo "$inode_info" | awk '/EXTENTS:/{ print NR; exit }')
> > +	get_extents=$(echo "$inode_info" | sed -n "$(($extents_line + 1))"p)
> > +
> > +	# get just the physical block numbers
> > +	get_extents=$(echo "$get_extents" |  perl -pe 's|\(.*?\):||g' | sed -e 's/, /\n/g' | perl -pe 's|(\d+)-(\d+)|\1 \2|g')
> > +
> > +	echo "$get_extents"
> > +}
> > +
> > +
> > +# checks all extents are zero'd out except for the superblock
> > +# arg 1: extents (output of get_journal_extents())
> > +check_extents() {
> > +	echo -e "\nChecking extents:" >> $seqres.full
> > +	echo "$1" >> $seqres.full
> > +
> > +	super_block="true"
> > +	echo "$1" | while IFS= read line; do
> > +		start_block=$(echo $line | cut -f1 -d' ')
> > +		end_block=$(echo $line | cut -f2 -d' ' -s)
> > +
> > +		# if first block of journal, shouldn't be wiped
> > +		if [ "$super_block" == "true" ]; then
> > +			super_block="false"
> > +
> > +			#if super block only block in this extent, skip extent
> > +			if [ -z "$end_block" ]; then
> > +				continue;
> > +			fi
> > +			start_block=$(($start_block + 1))
> > +		fi
> > +
> > +		if [ ! -z "$end_block" ]; then
> > +			blocks=$(($end_block - $start_block + 1))
> > +		else
> > +			blocks=1
> > +		fi
> > +
> > +		check=$(od $SCRATCH_DEV --skip-bytes=$(($start_block * $blocksize)) --read-bytes=$(($blocks * $blocksize)) -An -v | sed -e 's/[0 \t\n\r]//g')
> 
> I don't really like seeing long lines of pipe commands chained together
> since it sort of suggests that it's time for a helper function.  Ah
> well, that's just my style preference. :P
> 
> The logic of the shell script part looks reasonable to me though.
> 
> --D
> 

Thanks for the review! I'll send out a new version shortly.
-Leah

> > +
> > +		[ ! -z "$check" ] && echo "error" && break
> > +	done
> > +}
> > +
> > +testdir="${SCRATCH_MNT}/testdir"
> > +
> > +_scratch_mkfs_sized $((64 * 1024 * 1024)) >> $seqres.full 2>&1
> > +_require_metadata_journaling $SCRATCH_DEV
> > +_scratch_mount >> $seqres.full 2>&1
> > +blocksize=$(_get_block_size $SCRATCH_MNT)
> > +mkdir $testdir
> > +
> > +# check if ioctl present, skip test if not present
> > +$checkpoint_journal $SCRATCH_MNT --dry-run || _notrun "journal checkpoint ioctl not present on device"
> > +
> > +# create some files to add some entries to journal
> > +for i in {1..100}; do
> > +	echo > $testdir/$i
> > +done
> > +
> > +# make sure these files get to the journal
> > +sync --file-system $testdir/1
> > +
> > +# call ioctl to checkpoint and zero-fill journal blocks
> > +$checkpoint_journal $SCRATCH_MNT --erase=zeroout || _fail "ioctl returned error"
> > +
> > +extents=$(get_journal_extents)
> > +
> > +# check journal blocks zeroed out
> > +ret=$(check_extents "$extents")
> > +[ "$ret" = "error" ] && _fail "Journal was not zero-filled"
> > +
> > +_scratch_unmount >> $seqres.full 2>&1
> > +
> > +echo "Silence is golden"
> > +
> > +status=0
> > +exit
> > diff --git a/tests/ext4/310.out b/tests/ext4/310.out
> > new file mode 100644
> > index 00000000..7b9eaf78
> > --- /dev/null
> > +++ b/tests/ext4/310.out
> > @@ -0,0 +1,2 @@
> > +QA output created by 310
> > +Silence is golden
> > diff --git a/tests/ext4/group b/tests/ext4/group
> > index e7ad3c24..622590a9 100644
> > --- a/tests/ext4/group
> > +++ b/tests/ext4/group
> > @@ -60,3 +60,4 @@
> >  307 auto ioctl rw defrag
> >  308 auto ioctl rw prealloc quick defrag
> >  309 auto quick dir
> > +310 auto ioctl quick
> > -- 
> > 2.32.0.rc1.229.g3e70b5a671-goog
> >