tests/qemu-iotests/024 - qemu - Git at Google

 #!/usr/bin/env bash
 # group: rw backing auto quick
 #
 # Rebasing COW images
 #
 # Copyright (C) 2009 Red Hat, Inc.
 #
 # 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; either version 2 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will 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, see <http://www.gnu.org/licenses/>.
 #

 # creator
 owner=kwolf@redhat.com

 seq=`basename $0`
 echo "QA output created by $seq"

 status=1	# failure is the default!

 _cleanup()
 {
     _cleanup_test_img
     _rm_test_img "$TEST_DIR/t.$IMGFMT.base_old"
     _rm_test_img "$TEST_DIR/t.$IMGFMT.base_new"

     _rm_test_img "$TEST_DIR/subdir/t.$IMGFMT"
     _rm_test_img "$TEST_DIR/subdir/t.$IMGFMT.base_old"
     _rm_test_img "$TEST_DIR/subdir/t.$IMGFMT.base_new"
     rmdir "$TEST_DIR/subdir" 2> /dev/null
 }
 trap "_cleanup; exit \$status" 0 1 2 3 15

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

 # Currently only qcow2 and qed support rebasing
 _supported_fmt qcow2 qed
 _supported_proto file
 _supported_os Linux

 CLUSTER_SIZE=65536

 # Cluster allocations to be tested:
 #
 # Backing (old) 11  --  11  --  11  --  11  --
 # Backing (new) 22  22  --  --  22  22  --  --
 # COW image     33  33  33  33  --  --  --  --
 #
 # The pattern is written twice to have both an alloc -> non-alloc and a
 # non-alloc -> alloc transition in the COW image.

 echo "Creating backing file"
 echo

 TEST_IMG_SAVE="$TEST_IMG"
 TEST_IMG="$TEST_IMG.base_old"

 _make_test_img 1G
 io_pattern writev 0 $CLUSTER_SIZE $((2 * CLUSTER_SIZE)) 8 0x11

 TEST_IMG="$TEST_IMG_SAVE.base_new"

 echo "Creating new backing file"
 echo

 _make_test_img 1G
 io_pattern writev 0 $((2 * CLUSTER_SIZE)) $((4 * CLUSTER_SIZE)) 4 0x22


 TEST_IMG="$TEST_IMG_SAVE"

 echo "Creating COW image"
 echo

 _make_test_img -b "$TEST_IMG.base_old" -F $IMGFMT 1G
 io_pattern writev 0 $((4 * CLUSTER_SIZE)) 0 1 0x33
 io_pattern writev $((8 * CLUSTER_SIZE)) $((4 * CLUSTER_SIZE)) 0 1 0x33

 echo "Read before the rebase to make sure everything is set up correctly"
 echo
 io_pattern readv $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((4 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
 io_pattern readv $((5 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
 io_pattern readv $((6 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
 io_pattern readv $((7 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
 io_pattern readv $((8 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((9 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((10 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((11 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((12 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
 io_pattern readv $((13 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
 io_pattern readv $((14 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
 io_pattern readv $((15 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00

 echo
 echo Rebase and test again
 echo
 $QEMU_IMG rebase -b "$TEST_IMG.base_new" -F $IMGFMT "$TEST_IMG"
 io_pattern readv $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((4 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
 io_pattern readv $((5 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
 io_pattern readv $((6 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
 io_pattern readv $((7 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
 io_pattern readv $((8 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((9 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((10 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((11 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
 io_pattern readv $((12 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
 io_pattern readv $((13 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
 io_pattern readv $((14 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
 io_pattern readv $((15 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00

 echo
 echo "=== Test rebase in a subdirectory of the working directory ==="
 echo

 # Clean up the old images beforehand so they do not interfere with
 # this test
 _cleanup

 mkdir "$TEST_DIR/subdir"

 # Relative to the overlay
 BASE_OLD_OREL="t.$IMGFMT.base_old"
 BASE_NEW_OREL="t.$IMGFMT.base_new"

 # Relative to $TEST_DIR (which is going to be our working directory)
 OVERLAY_WREL="subdir/t.$IMGFMT"

 BASE_OLD="$TEST_DIR/subdir/$BASE_OLD_OREL"
 BASE_NEW="$TEST_DIR/subdir/$BASE_NEW_OREL"
 OVERLAY="$TEST_DIR/$OVERLAY_WREL"

 # Test done here:
 #
 # Backing (old): 11 11 -- 11
 # Backing (new): -- 22 22 11
 # Overlay:       -- -- -- --
 #
 # Rebasing works, we have verified that above.  Here, we just want to
 # see that rebasing is done for the correct target backing file.

 TEST_IMG=$BASE_OLD _make_test_img 1M
 TEST_IMG=$BASE_NEW _make_test_img 1M
 TEST_IMG=$OVERLAY _make_test_img -b "$BASE_OLD_OREL" -F $IMGFMT 1M

 echo

 $QEMU_IO "$BASE_OLD" \
     -c "write -P 0x11 $((0 * CLUSTER_SIZE)) $((2 * CLUSTER_SIZE))" \
     -c "write -P 0x11 $((3 * CLUSTER_SIZE)) $((1 * CLUSTER_SIZE))" \
     | _filter_qemu_io

 $QEMU_IO "$BASE_NEW" \
     -c "write -P 0x22 $((1 * CLUSTER_SIZE)) $((2 * CLUSTER_SIZE))" \
     -c "write -P 0x11 $((3 * CLUSTER_SIZE)) $((1 * CLUSTER_SIZE))" \
     | _filter_qemu_io

 echo

 pushd "$TEST_DIR" >/dev/null
 $QEMU_IMG rebase -f "$IMGFMT" -b "$BASE_NEW_OREL" -F $IMGFMT "$OVERLAY_WREL"
 popd >/dev/null

 # Verify the backing path is correct
 TEST_IMG=$OVERLAY _img_info | grep '^backing file:'

 echo

 # Verify the data is correct
 $QEMU_IO "$OVERLAY" \
     -c "read -P 0x11 $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
     -c "read -P 0x11 $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
     -c "read -P 0x00 $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
     -c "read -P 0x11 $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
     | _filter_qemu_io

 echo

 # Verify that cluster #3 is not allocated (because it is the same in
 # $BASE_OLD and $BASE_NEW)
 $QEMU_IMG map "$OVERLAY" | _filter_qemu_img_map

 # Check that rebase within the chain is working when
 # overlay_size > old_backing_size
 #
 # base_new <-- base_old <-- overlay
 #
 # Backing (new): 11 11 11 11 11
 # Backing (old): 22 22 22 22
 # Overlay:       -- -- -- -- --
 #
 # As a result, overlay should contain data identical to base_old, with the
 # last cluster remaining unallocated.

 echo
 echo "=== Test rebase within one backing chain ==="
 echo

 echo "Creating backing chain"
 echo

 TEST_IMG=$BASE_NEW _make_test_img $(( CLUSTER_SIZE * 5 ))
 TEST_IMG=$BASE_OLD _make_test_img -b "$BASE_NEW" -F $IMGFMT \
     $(( CLUSTER_SIZE * 4 ))
 TEST_IMG=$OVERLAY _make_test_img -b "$BASE_OLD" -F $IMGFMT \
     $(( CLUSTER_SIZE * 5 ))

 echo
 echo "Fill backing files with data"
 echo

 $QEMU_IO "$BASE_NEW" -c "write -P 0x11 0 $(( CLUSTER_SIZE * 5 ))" \
     | _filter_qemu_io
 $QEMU_IO "$BASE_OLD" -c "write -P 0x22 0 $(( CLUSTER_SIZE * 4 ))" \
     | _filter_qemu_io

 echo
 echo "Check the last cluster is zeroed in overlay before the rebase"
 echo
 $QEMU_IO "$OVERLAY" -c "read -P 0x00 $(( CLUSTER_SIZE * 4 )) $CLUSTER_SIZE" \
     | _filter_qemu_io

 echo
 echo "Rebase onto another image in the same chain"
 echo

 $QEMU_IMG rebase -b "$BASE_NEW" -F $IMGFMT "$OVERLAY"

 echo "Verify that data is read the same before and after rebase"
 echo

 # Verify the first 4 clusters are still read the same as in the old base
 $QEMU_IO "$OVERLAY" -c "read -P 0x22 0 $(( CLUSTER_SIZE * 4 ))" \
     | _filter_qemu_io
 # Verify the last cluster still reads as zeroes
 $QEMU_IO "$OVERLAY" -c "read -P 0x00 $(( CLUSTER_SIZE * 4 )) $CLUSTER_SIZE" \
     | _filter_qemu_io

 echo

 # Check that rebase within the chain is working when
 # overlay cluster size > backings cluster size
 # (here overlay cluster size == 2 * backings cluster size)
 #
 # base_new <-- base_old <-- overlay
 #
 # Backing (new): -- -- -- -- -- --
 # Backing (old): -- 11 -- -- 22 --
 # Overlay:      |-- --|-- --|-- --|
 #
 # We should end up having 1st and 3rd cluster allocated, and their halves
 # being read as zeroes.

 echo
 echo "=== Test rebase with different cluster sizes ==="
 echo

 echo "Creating backing chain"
 echo

 TEST_IMG=$BASE_NEW _make_test_img $(( CLUSTER_SIZE * 6 ))
 TEST_IMG=$BASE_OLD _make_test_img -b "$BASE_NEW" -F $IMGFMT \
     $(( CLUSTER_SIZE * 6 ))
 CLUSTER_SIZE=$(( CLUSTER_SIZE * 2 )) TEST_IMG=$OVERLAY \
     _make_test_img -b "$BASE_OLD" -F $IMGFMT $(( CLUSTER_SIZE * 6 ))

 TEST_IMG=$OVERLAY _img_info

 echo
 echo "Fill backing files with data"
 echo

 $QEMU_IO "$BASE_OLD" -c "write -P 0x11 $CLUSTER_SIZE $CLUSTER_SIZE" \
     -c "write -P 0x22 $(( CLUSTER_SIZE * 4 )) $CLUSTER_SIZE" \
     | _filter_qemu_io

 echo
 echo "Rebase onto another image in the same chain"
 echo

 $QEMU_IMG rebase -b "$BASE_NEW" -F $IMGFMT "$OVERLAY"

 echo "Verify that data is read the same before and after rebase"
 echo

 $QEMU_IO "$OVERLAY" -c "read -P 0x00 0 $CLUSTER_SIZE" \
     -c "read -P 0x11 $CLUSTER_SIZE $CLUSTER_SIZE" \
     -c "read -P 0x00 $(( CLUSTER_SIZE * 2 )) $(( CLUSTER_SIZE * 2 ))" \
     -c "read -P 0x22 $(( CLUSTER_SIZE * 4 )) $CLUSTER_SIZE" \
     -c "read -P 0x00 $(( CLUSTER_SIZE * 5 )) $CLUSTER_SIZE" \
     | _filter_qemu_io

 echo
 echo "Verify that untouched cluster remains unallocated"
 echo

 $QEMU_IMG map "$OVERLAY" | _filter_qemu_img_map

 echo

 # success, all done
 echo "*** done"
 rm -f $seq.full
 status=0
	#!/usr/bin/env bash
	# group: rw backing auto quick
	#
	# Rebasing COW images
	#
	# Copyright (C) 2009 Red Hat, Inc.
	#
	# 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; either version 2 of the License, or
	# (at your option) any later version.
	#
	# This program is distributed in the hope that it will 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, see <http://www.gnu.org/licenses/>.
	#

	# creator
	owner=kwolf@redhat.com

	seq=`basename $0`
	echo "QA output created by $seq"

	status=1 # failure is the default!

	_cleanup()
	{
	_cleanup_test_img
	_rm_test_img "$TEST_DIR/t.$IMGFMT.base_old"
	_rm_test_img "$TEST_DIR/t.$IMGFMT.base_new"

	_rm_test_img "$TEST_DIR/subdir/t.$IMGFMT"
	_rm_test_img "$TEST_DIR/subdir/t.$IMGFMT.base_old"
	_rm_test_img "$TEST_DIR/subdir/t.$IMGFMT.base_new"
	rmdir "$TEST_DIR/subdir" 2> /dev/null
	}
	trap "_cleanup; exit \$status" 0 1 2 3 15

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

	# Currently only qcow2 and qed support rebasing
	_supported_fmt qcow2 qed
	_supported_proto file
	_supported_os Linux

	CLUSTER_SIZE=65536

	# Cluster allocations to be tested:
	#
	# Backing (old) 11 -- 11 -- 11 -- 11 --
	# Backing (new) 22 22 -- -- 22 22 -- --
	# COW image 33 33 33 33 -- -- -- --
	#
	# The pattern is written twice to have both an alloc -> non-alloc and a
	# non-alloc -> alloc transition in the COW image.

	echo "Creating backing file"
	echo

	TEST_IMG_SAVE="$TEST_IMG"
	TEST_IMG="$TEST_IMG.base_old"

	_make_test_img 1G
	io_pattern writev 0 $CLUSTER_SIZE $((2 * CLUSTER_SIZE)) 8 0x11

	TEST_IMG="$TEST_IMG_SAVE.base_new"

	echo "Creating new backing file"
	echo

	_make_test_img 1G
	io_pattern writev 0 $((2 * CLUSTER_SIZE)) $((4 * CLUSTER_SIZE)) 4 0x22


	TEST_IMG="$TEST_IMG_SAVE"

	echo "Creating COW image"
	echo

	_make_test_img -b "$TEST_IMG.base_old" -F $IMGFMT 1G
	io_pattern writev 0 $((4 * CLUSTER_SIZE)) 0 1 0x33
	io_pattern writev $((8 * CLUSTER_SIZE)) $((4 * CLUSTER_SIZE)) 0 1 0x33

	echo "Read before the rebase to make sure everything is set up correctly"
	echo
	io_pattern readv $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((4 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
	io_pattern readv $((5 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
	io_pattern readv $((6 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
	io_pattern readv $((7 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
	io_pattern readv $((8 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((9 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((10 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((11 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((12 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
	io_pattern readv $((13 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
	io_pattern readv $((14 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
	io_pattern readv $((15 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00

	echo
	echo Rebase and test again
	echo
	$QEMU_IMG rebase -b "$TEST_IMG.base_new" -F $IMGFMT "$TEST_IMG"
	io_pattern readv $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((4 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
	io_pattern readv $((5 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
	io_pattern readv $((6 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
	io_pattern readv $((7 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
	io_pattern readv $((8 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((9 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((10 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((11 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
	io_pattern readv $((12 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
	io_pattern readv $((13 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
	io_pattern readv $((14 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
	io_pattern readv $((15 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00

	echo
	echo "=== Test rebase in a subdirectory of the working directory ==="
	echo

	# Clean up the old images beforehand so they do not interfere with
	# this test
	_cleanup

	mkdir "$TEST_DIR/subdir"

	# Relative to the overlay
	BASE_OLD_OREL="t.$IMGFMT.base_old"
	BASE_NEW_OREL="t.$IMGFMT.base_new"

	# Relative to $TEST_DIR (which is going to be our working directory)
	OVERLAY_WREL="subdir/t.$IMGFMT"

	BASE_OLD="$TEST_DIR/subdir/$BASE_OLD_OREL"
	BASE_NEW="$TEST_DIR/subdir/$BASE_NEW_OREL"
	OVERLAY="$TEST_DIR/$OVERLAY_WREL"

	# Test done here:
	#
	# Backing (old): 11 11 -- 11
	# Backing (new): -- 22 22 11
	# Overlay: -- -- -- --
	#
	# Rebasing works, we have verified that above. Here, we just want to
	# see that rebasing is done for the correct target backing file.

	TEST_IMG=$BASE_OLD _make_test_img 1M
	TEST_IMG=$BASE_NEW _make_test_img 1M
	TEST_IMG=$OVERLAY _make_test_img -b "$BASE_OLD_OREL" -F $IMGFMT 1M

	echo

	$QEMU_IO "$BASE_OLD" \
	-c "write -P 0x11 $((0 * CLUSTER_SIZE)) $((2 * CLUSTER_SIZE))" \
	-c "write -P 0x11 $((3 * CLUSTER_SIZE)) $((1 * CLUSTER_SIZE))" \
	\| _filter_qemu_io

	$QEMU_IO "$BASE_NEW" \
	-c "write -P 0x22 $((1 * CLUSTER_SIZE)) $((2 * CLUSTER_SIZE))" \
	-c "write -P 0x11 $((3 * CLUSTER_SIZE)) $((1 * CLUSTER_SIZE))" \
	\| _filter_qemu_io

	echo

	pushd "$TEST_DIR" >/dev/null
	$QEMU_IMG rebase -f "$IMGFMT" -b "$BASE_NEW_OREL" -F $IMGFMT "$OVERLAY_WREL"
	popd >/dev/null

	# Verify the backing path is correct
	TEST_IMG=$OVERLAY _img_info \| grep '^backing file:'

	echo

	# Verify the data is correct
	$QEMU_IO "$OVERLAY" \
	-c "read -P 0x11 $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
	-c "read -P 0x11 $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
	-c "read -P 0x00 $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
	-c "read -P 0x11 $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
	\| _filter_qemu_io

	echo

	# Verify that cluster #3 is not allocated (because it is the same in
	# $BASE_OLD and $BASE_NEW)
	$QEMU_IMG map "$OVERLAY" \| _filter_qemu_img_map

	# Check that rebase within the chain is working when
	# overlay_size > old_backing_size
	#
	# base_new <-- base_old <-- overlay
	#
	# Backing (new): 11 11 11 11 11
	# Backing (old): 22 22 22 22
	# Overlay: -- -- -- -- --
	#
	# As a result, overlay should contain data identical to base_old, with the
	# last cluster remaining unallocated.

	echo
	echo "=== Test rebase within one backing chain ==="
	echo

	echo "Creating backing chain"
	echo

	TEST_IMG=$BASE_NEW _make_test_img $(( CLUSTER_SIZE * 5 ))
	TEST_IMG=$BASE_OLD _make_test_img -b "$BASE_NEW" -F $IMGFMT \
	$(( CLUSTER_SIZE * 4 ))
	TEST_IMG=$OVERLAY _make_test_img -b "$BASE_OLD" -F $IMGFMT \
	$(( CLUSTER_SIZE * 5 ))

	echo
	echo "Fill backing files with data"
	echo

	$QEMU_IO "$BASE_NEW" -c "write -P 0x11 0 $(( CLUSTER_SIZE * 5 ))" \
	\| _filter_qemu_io
	$QEMU_IO "$BASE_OLD" -c "write -P 0x22 0 $(( CLUSTER_SIZE * 4 ))" \
	\| _filter_qemu_io

	echo
	echo "Check the last cluster is zeroed in overlay before the rebase"
	echo
	$QEMU_IO "$OVERLAY" -c "read -P 0x00 $(( CLUSTER_SIZE * 4 )) $CLUSTER_SIZE" \
	\| _filter_qemu_io

	echo
	echo "Rebase onto another image in the same chain"
	echo

	$QEMU_IMG rebase -b "$BASE_NEW" -F $IMGFMT "$OVERLAY"

	echo "Verify that data is read the same before and after rebase"
	echo

	# Verify the first 4 clusters are still read the same as in the old base
	$QEMU_IO "$OVERLAY" -c "read -P 0x22 0 $(( CLUSTER_SIZE * 4 ))" \
	\| _filter_qemu_io
	# Verify the last cluster still reads as zeroes
	$QEMU_IO "$OVERLAY" -c "read -P 0x00 $(( CLUSTER_SIZE * 4 )) $CLUSTER_SIZE" \
	\| _filter_qemu_io

	echo

	# Check that rebase within the chain is working when
	# overlay cluster size > backings cluster size
	# (here overlay cluster size == 2 * backings cluster size)
	#
	# base_new <-- base_old <-- overlay
	#
	# Backing (new): -- -- -- -- -- --
	# Backing (old): -- 11 -- -- 22 --
	# Overlay: \|-- --\|-- --\|-- --\|
	#
	# We should end up having 1st and 3rd cluster allocated, and their halves
	# being read as zeroes.

	echo
	echo "=== Test rebase with different cluster sizes ==="
	echo

	echo "Creating backing chain"
	echo

	TEST_IMG=$BASE_NEW _make_test_img $(( CLUSTER_SIZE * 6 ))
	TEST_IMG=$BASE_OLD _make_test_img -b "$BASE_NEW" -F $IMGFMT \
	$(( CLUSTER_SIZE * 6 ))
	CLUSTER_SIZE=$(( CLUSTER_SIZE * 2 )) TEST_IMG=$OVERLAY \
	_make_test_img -b "$BASE_OLD" -F $IMGFMT $(( CLUSTER_SIZE * 6 ))

	TEST_IMG=$OVERLAY _img_info

	echo
	echo "Fill backing files with data"
	echo

	$QEMU_IO "$BASE_OLD" -c "write -P 0x11 $CLUSTER_SIZE $CLUSTER_SIZE" \
	-c "write -P 0x22 $(( CLUSTER_SIZE * 4 )) $CLUSTER_SIZE" \
	\| _filter_qemu_io

	echo
	echo "Rebase onto another image in the same chain"
	echo

	$QEMU_IMG rebase -b "$BASE_NEW" -F $IMGFMT "$OVERLAY"

	echo "Verify that data is read the same before and after rebase"
	echo

	$QEMU_IO "$OVERLAY" -c "read -P 0x00 0 $CLUSTER_SIZE" \
	-c "read -P 0x11 $CLUSTER_SIZE $CLUSTER_SIZE" \
	-c "read -P 0x00 $(( CLUSTER_SIZE * 2 )) $(( CLUSTER_SIZE * 2 ))" \
	-c "read -P 0x22 $(( CLUSTER_SIZE * 4 )) $CLUSTER_SIZE" \
	-c "read -P 0x00 $(( CLUSTER_SIZE * 5 )) $CLUSTER_SIZE" \
	\| _filter_qemu_io

	echo
	echo "Verify that untouched cluster remains unallocated"
	echo

	$QEMU_IMG map "$OVERLAY" \| _filter_qemu_img_map

	echo

	# success, all done
	echo "*** done"
	rm -f $seq.full
	status=0