fstests: add dm-log-writes test and supporting code

This patch adds the supporting code for using the dm-log-writes target.  The
bash stuff is similar to the dmflakey code, it just gives us functions to build
and tear down a dm-log-writes target.  We add a new LOGWRITES_DEV variable to
take in the device we will use as the log and add checks for that.

I've rigged up fsx to have an integrity check mode.  Basically it works like it
normally works, but when it fsync()'s it marks the log with a unique mark and
dumps it's buffer to a file with the mark in the filename.  I did this with a
system() call simply because it was the fastest.  I can link the device-mapper
libraries and do it programatically if that would be preferred, but this works
pretty well.

The test itself just runs 200 ops and exits, then finds all of the good buffers
in the directory we provided and replays up to the mark given, mounts the file
system and compares the md5sum, unmounts and fsck's to check for metadata
integrity.  dm-log-writes will pretend to do discard and the replay tool will
replay it properly depending on the underlying device, either by writing 0's or
actually calling the discard ioctl, so I've enabled discard in the test for
maximum fun.

This test relies on the supporting userspace code I've written for
dm-logs-writes.  It can be found here

https://github.com/josefbacik/log-writes.git

Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>

README

@@ -78,6 +78,8 @@ Preparing system for tests (IRIX and Linux):
                added to the end of fsstresss and fsx invocations, respectively,
                in case you wish to exclude certain operational modes from these
                tests.
+             - setenv LOGWRITES_DEV to a block device to use for power fail
+               testing.
 
         - or add a case to the switch in common/config assigning
           these variables based on the hostname of your test

common/config

@@ -191,6 +191,7 @@ export WIPEFS_PROG="`set_prog_path wipefs`"
 export DUMP_PROG="`set_prog_path dump`"
 export RESTORE_PROG="`set_prog_path restore`"
 export LVM_PROG="`set_prog_path lvm`"
+export REPLAYLOG_PROG="`set_prog_path replay-log`"
 
 # Generate a comparable xfsprogs version number in the form of
 # major * 10000 + minor * 100 + release

common/dmlogwrites

@@ -0,0 +1,80 @@
+##/bin/bash
+#
+# Copyright (c) 2015 Facebook, Inc.  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
+#
+#
+# common functions for setting up and tearing down a dm log-writes device
+
+_init_log_writes()
+{
+	local BLK_DEV_SIZE=`blockdev --getsz $SCRATCH_DEV`
+	LOGWRITES_NAME=logwrites-test
+	LOGWRITES_DMDEV=/dev/mapper/$LOGWRITES_NAME
+	LOGWRITES_TABLE="0 $BLK_DEV_SIZE log-writes $SCRATCH_DEV $LOGWRITES_DEV"
+	$DMSETUP_PROG create $LOGWRITES_NAME --table "$LOGWRITES_TABLE" || \
+		_fatal "failed to create log-writes device"
+	$DMSETUP_PROG mknodes > /dev/null 2>&1
+}
+
+_log_writes_mark()
+{
+	[ $# -ne 1 ] && _fatal "_log_writes_mark takes one argument"
+	$DMSETUP_PROG message $LOGWRITES_NAME 0 mark $1
+}
+
+_log_writes_mkfs()
+{
+	_scratch_options mkfs
+	_mkfs_dev $SCRATCH_OPTIONS $LOGWRITES_DMDEV
+	_log_writes_mark mkfs
+}
+
+_mount_log_writes()
+{
+	mount -t $FSTYP $MOUNT_OPTIONS $* $LOGWRITES_DMDEV $SCRATCH_MNT
+}
+
+_unmount_log_writes()
+{
+	$UMOUNT_PROG $SCRATCH_MNT
+}
+
+# _replay_log <mark>
+#
+# This replays the log contained on $INTEGRITY_DEV onto $SCRATCH_DEV upto the
+# mark passed in.
+_replay_log()
+{
+	_mark=$1
+
+	$REPLAYLOG_PROG --log $LOGWRITES_DEV --replay $SCRATCH_DEV \
+		--end-mark $_mark > /dev/null 2>&1
+	[ $? -ne 0 ] && _fatal "replay failed"
+}
+
+_log_writes_remove()
+{
+	$DMSETUP_PROG remove $LOGWRITES_NAME > /dev/null 2>&1
+	$DMSETUP_PROG mknodes > /dev/null 2>&1
+}
+
+_cleanup_log_writes()
+{
+	# If dmsetup load fails then we need to make sure to do resume here
+	# otherwise the umount will hang
+	$UMOUNT_PROG $SCRATCH_MNT > /dev/null 2>&1
+	_log_writes_remove
+}

common/rc

@@ -1357,6 +1357,24 @@ _require_dm_snapshot()
 	fi
 }
 
+# this test requires the device mapper log-writes target
+#
+_require_dm_log_writes()
+{
+	[ -z $LOGWRITES_DEV ] && _notrun "This test requires a logwrites dev"
+	_require_block_device $SCRATCH_DEV
+	_require_block_device $LOGWRITES_DEV
+	_require_command $DMSETUP_PROG
+	_require_command $REPLAYLOG_PROG
+
+	modprobe dm-log-writes >/dev/null 2>&1
+	$DMSETUP_PROG targets | grep "log-writes" > /dev/null 2>&1
+	if [ $? -ne 0 ]
+	then
+		_notrun "This test requires dm log-writes support"
+	fi
+}
+
 # this test requires the projid32bit feature to be available in mkfs.xfs.
 #
 _require_projid32bit()
@@ -1591,6 +1609,34 @@ _require_xfs_io_command()
 		_notrun "xfs_io $command failed (old kernel/wrong fs?)"
 }
 
+_test_falloc_support()
+{
+	if [ $# -ne 1 ]
+	then
+		echo "Usage: _test_falloc_support command" 1>&2
+		exit 1
+	fi
+	command=$1
+
+	testfile=$TEST_DIR/$$.xfs_io
+	case $command in
+	"fpunch" | "fcollapse" | "zero" | "fzero" | "finsert" )
+		testio=`$XFS_IO_PROG -F -f -c "pwrite 0 20k" -c "fsync" \
+			-c "$command 4k 8k" $testfile 2>&1`
+		;;
+	*)
+		echo "Not a valid falloc command" 1>&2
+		exit 1
+	esac
+
+	rm -f $testfile 2>&1 > /dev/null
+	echo $testio | grep -q "not found" && \
+		return 0
+	echo $testio | grep -q "Operation not supported" && \
+		return 0
+	return 1
+}
+
 # check that kernel and filesystem support direct I/O
 _require_odirect()
 {