#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
#
# FS QA Test No. 189
#
# Test remount behaviour
# Initial motivation was for pv#985710 and pv#983964
#
# mount(8) adds all options from mtab and fstab to the mount command line.  So
# the filesystem either must not reject any option at all if it can't change it,
# or compare the value on the command line to the existing state and only reject
# it if it would change something that can't be changed.
#
# Test this behaviour by mounting a filesystem read-only with a non- default
# option and then try to remount it rw.
#
# note that mount(8) doesn't add the options when specifying both the device
# node and mount point, so test out the various mounting alternatives
#
# <---- Bbbzzzzzzztttt ---->
#
# Right, but the kernel /proc/mounts output in no way reflects what mount passes
# into the kernel, so the entire assumption of this test that what mount outputs
# is the same as what it inputs is completely wrong.
#
# Hence the test now checks to see if the expected options are in the mount
# options in /etc/mtab rather than looking for an exact match. Hence the tests
# check what we know should change, not what mount thinks has changed. As a
# result, the test now passes regardless of whether mount or the kernel controls
# the contents of /etc/mtab....
#
# <---- Normal programming is resumed ---->
#
#
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
tag="added by qa $seq"

rm -f $seqres.full

_cleanup()
{
	cd /
	_scratch_unmount 2>/dev/null
	_putback_scratch_fstab
	rm -f $tmp.*
}

_scratch_filter()
{
	sed -e "s#$SCRATCH_DEV#SCRATCH_DEV#" \
	    -e "s#$SCRATCH_MNT#SCRATCH_MNT#" \
	    -e "s#,context.*s0\"##"
}

#
# the output from /proc/mounts in no way matches what mount puts into the kernel
# as options. Work around it as best possible by matching the strings passed in
# rather than assuming they are the only options that will be set. If they match
# output them to the output file so that the golden image and the filtering
# doesn't need to care about what options may or may not be present in /etc/mtab
#
_check_mount()
{
	rw_or_ro=$1
	expected_val=$2

	[ -z "$expected_val" ] && expected_val=$1

	_mount | grep $SCRATCH_MNT | _scratch_filter | \
		tee -a $seqres.full |
		grep $rw_or_ro | grep $expected_val > /dev/null
	if [ $? -eq 0 ]; then
		echo -n "SCRATCH_DEV on SCRATCH_MNT type xfs ($rw_or_ro"
		if [ ! -z "$2" ]; then
			echo -n ",$2"
		fi
		echo ")"
	fi
}

_test_remount_rw()
{
	# use filestreams as a hopefully never default option
	echo
	echo "try remount ro,filestreams -> rw,filestreams"
	echo
	_try_scratch_mount -o ro,filestreams
	[ $? -eq 0 ] || echo "ro,filestreams mount failed unexpectedly"
	_check_mount ro filestreams

	for dev_mnt in $SCRATCH_DEV $SCRATCH_MNT "$SCRATCH_DEV $SCRATCH_MNT"; do
		echo "mounting given: $dev_mnt" | _scratch_filter
		_mount -o remount,rw,filestreams $dev_mnt
		[ $? -eq 0 ] || echo "remount rw failed"
		_check_mount rw filestreams
	done

	_scratch_unmount

	# remount ignores attr2, and noattr2 mount option does does not result
	# in any "attr2" specific option in /proc/mounts, so we can only check
	# for ro/rw here.
	echo
	echo "try remount ro,noattr2 -> rw,attr2"
	echo
	_try_scratch_mount -o ro,noattr2
	[ $? -eq 0 ] || echo "ro,noattr2 mount failed unexpectedly"
	_check_mount ro

	for dev_mnt in $SCRATCH_DEV $SCRATCH_MNT "$SCRATCH_DEV $SCRATCH_MNT"; do
		echo "mounting given: $dev_mnt" | _scratch_filter
		_mount -o remount,rw,attr2 $dev_mnt
		[ $? -eq 0 ] || echo "remount rw,attr2 failed"
		_check_mount rw
	done

	_scratch_unmount
}

#
# make sure we really can write to a filesystem after remount,rw
#
_test_remount_write()
{
	echo
	echo "try touching file after remount ro -> rw with options"
	echo
	_try_scratch_mount
	[ $? -eq 0 ] || echo "mount (1) failed unexpectedly"

	touch $SCRATCH_MNT/foobar
	[ $? -eq 0 ] || echo "touch (1) failed unexpectedly"

	_scratch_unmount

	_try_scratch_mount -o ro
	[ $? -eq 0 ] || echo "mount (2) failed unexpectedly"

	_mount -o remount,rw,filestreams $SCRATCH_MNT
	[ $? -eq 0 ] || echo "remount failed unexpectedly"

	touch $SCRATCH_MNT/foobar
	[ $? -eq 0 ] || echo "touch (2) failed unexpectedly"

	_scratch_unmount
}

#
# barrier is the only option we can change besides ro<->rw which is partially
# handled by the VFS and tested elsewhere.  Make sure mount accepts going
# from barrier (which also is the default) to nobarrier and back.
#
_test_remount_barrier()
{
	echo
	echo "Do remount barrier tests"
	echo

	# mention barrier explicitly even if it's currently the default just to be sure
	_try_scratch_mount -o barrier
	[ $? -eq 0 ] || echo "mount failed unexpectedly!"
	_check_mount rw

	_try_scratch_mount -o remount,nobarrier
	[ $? -eq 0 ] || _fail "remount nobarrier failed"
	_check_mount rw nobarrier

	_try_scratch_mount -o remount,barrier
	[ $? -eq 0 ] || _fail "remount barrier failed"
	_check_mount rw

	_scratch_unmount
}

#
# Example fstab entry
# /dev/sdb2            /mnt/scratch1        xfs       defaults 0 0
#
_add_scratch_fstab()
{
	# comment out any existing SCRATCH_DEV
	$SED_PROG -i "s;$SCRATCH_DEV;#$SCRATCH_DEV;" /etc/fstab

	# add our fstab entry
	echo "$SCRATCH_DEV $SCRATCH_MNT xfs defaults 0 0 # $tag" >> /etc/fstab
}

_modify_scratch_fstab()
{
	opts=$1

	# modify our fstab entry that we added
	# modify opts by looking for last word which has non-space chars
	$SED_PROG -i "s; [^ ]* 0 0 # $tag; $opts 0 0 # $tag;" /etc/fstab
}

_putback_scratch_fstab()
{
	# uncomment out any existing SCRATCH_DEV
	$SED_PROG -i "s;#$SCRATCH_DEV;$SCRATCH_DEV;" /etc/fstab

	# remove the one we added at the end
	$SED_PROG -i "/# $tag/d" /etc/fstab
}

# get standard environment, filters and checks
. ./common/rc
. ./common/filter
. ./common/attr

# real QA test starts here
_supported_fs xfs
_supported_os Linux

_require_no_realtime
_require_scratch
_require_noattr2

unset SCRATCH_RTDEV
unset SCRATCH_LOGDEV

_scratch_mkfs_xfs | _filter_mkfs 2>/dev/null

_add_scratch_fstab
_test_remount_rw
_test_remount_write

echo
echo "add noikeep to fstab for scratch"
_modify_scratch_fstab noikeep # noikeep is not default for non dmapi
_test_remount_rw

_putback_scratch_fstab
_test_remount_barrier

# success, all done
echo "*** done"
status=0