test_description="e2undo and mke2fs with offset option"
OUT="$test_name.log"
TDB_FILE="$TMPFILE.e2undo"

E2UNDO_FEATURE_COMPAT_OFFSET=1

trap "rm -f $TDB_FILE" EXIT INT QUIT

test_e2undo_mke2fs_off() {
	OFF=$1

	rm -f "$TDB_FILE"
	echo "testing e2undo and mke2fs with the -E offset=$OFF option" >> "$OUT"
	# prepare $TMPFILE
	yes a | dd of="$TMPFILE" bs="$OFF" count=1 iflag=fullblock \
		> /dev/null 2>>"$OUT"
	yes b | dd bs=1k count=1024 iflag=fullblock >> "$TMPFILE" 2>>"$OUT"
	yes c | dd bs=1k count=3 iflag=fullblock >> "$TMPFILE" 2>>"$OUT"

	crc_exp=`$CRCSUM "$TMPFILE"`
	$MKE2FS -F -z "$TDB_FILE" -b 1024 -E offset="$OFF" "$TMPFILE" 1024 \
		>> "$OUT" 2>&1

	# supplement test with offset specific data
	supplement_test_$OFF

	# dump undo header (just to ease debugging in case of a failure)
	echo "undo header:" >> "$OUT"
	$E2UNDO -h "$TDB_FILE" "$TMPFILE" >> "$OUT" 2>&1

	# offset is stored in the undo header
	$E2UNDO "$TDB_FILE" "$TMPFILE" >> "$OUT" 2>&1
	crc_act=`$CRCSUM "$TMPFILE"`

	# also test the key extension code path: the key for the fs block 960
	# (tdb block 30) is extended by the fs block 992 (tdb block 31)
	# => we have exactly 3 key blocks instead of 4
	num_keys_exp=3
	num_keys_act=`$E2UNDO -h "$TDB_FILE" "$TMPFILE" | grep "^nr keys:" \
		| cut -f2`

	offset_exp=$OFF
	offset_act=`$E2UNDO -h "$TDB_FILE" "$TMPFILE" | grep "^fs offset:" \
		| cut -f2`
	compat_exp=$E2UNDO_FEATURE_COMPAT_OFFSET
	compat_act=`$E2UNDO -h "$TDB_FILE" "$TMPFILE" | grep "^compat:" | cut -f3`

	if [ "$crc_exp" != "$crc_act" -o \
		 "$num_keys_exp" != "$num_keys_act" -o \
		 "$offset_exp" != "$offset_act" -o \
		 $(($compat_act & $E2UNDO_FEATURE_COMPAT_OFFSET)) -ne $compat_exp ]
		 then
		echo "mke2fs called with offset: $OFF" >> "$test_name.failed"
		echo "crc_exp: $crc_exp" >> "$test_name.failed"
		echo "crc_act: $crc_act" >> "$test_name.failed"
		echo "num_keys_exp: $num_keys_exp" >> "$test_name.failed"
		echo "num_keys_act: $num_keys_act" >> "$test_name.failed"
		echo "offset_exp: $offset_exp" >> "$test_name.failed"
		echo "offset_act: $offset_act" >> "$test_name.failed"
		echo "compat_exp: $compat_exp" >> "$test_name.failed"
		echo "compat_act: $compat_act" >> "$test_name.failed"
		echo >> "$test_name.failed"
	fi
}

supplement_test_2048() {
	# modify the two subsequent 1k blocks (1026 and 1027) after the fs end:
	# e2undo will overwrite these modified blocks with the old
	# data again (this might be considered as a bug (for now,
	# this testcase just documents this behavior))
	SEEK_BLOCKS=$(((2048 + 1024 * 1024) / 1024))
	yes d | dd of="$TMPFILE" bs=1k count=2 seek="$SEEK_BLOCKS" \
		iflag=fullblock > /dev/null 2>>"$OUT"
}

supplement_test_96255() {
	# nothing to supplement
	:
}

# test even offset < tdb_data_size
# with an offset of 2048 the old code wrote an incorrect undo file,
# for example, the computations for fs block 0 were wrong:
# * backing_blk_num was set to ULLONG_MAX - 1 instead of 0
# * data was read from the beginning of the file instead of offset 2048
# * data_ptr was set to read_ptr - 2048
# for details, see the old undo_write_tdb code in undo_io.c
test_e2undo_mke2fs_off 2048

# test odd offset > tdb_data_size: 32768 * 3 - 2 * 1024 - 1
# a somewhat arbitrary value, for example, during the backup of
# fs block 0 such an offset resulted in:
# * the largest "in fs block offset" (96255 % 1024 == 1023)
# * a wrong value for data_size (actual bytes read: 31745)
# * an invalid address for data_ptr
# for details, see the old undo_write_tdb code in undo_io.c
test_e2undo_mke2fs_off 96255

if [ -e "$test_name.failed" ]; then
	echo "$test_name: $test_description: failed"
else
	echo "$test_name: $test_description: ok"
	touch "$test_name.ok"
fi