btrfs: test incremental send after deduplication on both snapshots

Test that an incremental send operation works after deduplicating into the
same file in both the parent and send snapshots.

This currently fails on btrfs and a kernel patch to fix it was submitted
with the subject:

  Btrfs: fix incremental send failure after deduplication

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

tests/btrfs/191

@@ -0,0 +1,110 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2019 SUSE Linux Products GmbH. All Rights Reserved.
+#
+# FS QA Test No. btrfs/191
+#
+# Test that an incremental send operation works after deduplicating into the
+# same file in both the parent and send snapshots.
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -fr $send_files_dir
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/reflink
+
+# real QA test starts here
+_supported_fs btrfs
+_supported_os Linux
+_require_test
+_require_scratch_dedupe
+_require_fssum
+
+send_files_dir=$TEST_DIR/btrfs-test-$seq
+
+rm -f $seqres.full
+rm -fr $send_files_dir
+mkdir $send_files_dir
+
+_scratch_mkfs >>$seqres.full 2>&1
+_scratch_mount
+
+# Create our first file. The first half of the file has several 64Kb extents
+# while the second half as a single 512Kb extent.
+$XFS_IO_PROG -f -s -c "pwrite -S 0xb8 -b 64K 0 512K" $SCRATCH_MNT/foo \
+	| _filter_xfs_io
+$XFS_IO_PROG -c "pwrite -S 0xb8 512K 512K" $SCRATCH_MNT/foo | _filter_xfs_io
+
+# Create the base snapshot and the parent send stream from it.
+$BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap1 \
+	| _filter_scratch
+
+$BTRFS_UTIL_PROG send -f $send_files_dir/1.snap $SCRATCH_MNT/mysnap1 2>&1 \
+	| _filter_scratch
+
+# Create our second file, that has exactly the same data as the first file.
+$XFS_IO_PROG -f -c "pwrite -S 0xb8 0 1M" $SCRATCH_MNT/bar | _filter_xfs_io
+
+# Create the second snapshot, used for the incremental send, before doing the
+# file deduplication.
+$BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap2 \
+	| _filter_scratch
+
+# Now before creating the incremental send stream:
+#
+# 1) Deduplicate into a subrange of file foo in snapshot mysnap1. This will drop
+#    several extent items and add a new one, also updating the inode's iversion
+#    (sequence field in inode item) by 1, but not any other field of the inode;
+#
+# 2) Deduplicate into a different subrange of file foo in snapshot mysnap2. This
+#    will replace an extent item with a new one, also updating the inode's
+#    iversion by 1 but not any other field of the inode.
+#
+# After these two deduplication operations, the inode items, for file foo, are
+# identical in both snapshots, but we have different extent items for this inode
+# in both snapshots. We want to check this doesn't cause send to fail with an
+# error or produce an incorrect stream.
+
+$XFS_IO_PROG -r -c "dedupe $SCRATCH_MNT/bar 0 0 512K" $SCRATCH_MNT/mysnap1/foo \
+	| _filter_xfs_io
+
+$XFS_IO_PROG -r -c "dedupe $SCRATCH_MNT/bar 512K 512K 512K" \
+	$SCRATCH_MNT/mysnap2/foo | _filter_xfs_io
+
+# Create the incremental send stream.
+$BTRFS_UTIL_PROG send -p $SCRATCH_MNT/mysnap1 -f $send_files_dir/2.snap \
+	$SCRATCH_MNT/mysnap2 2>&1 | _filter_scratch
+
+# Create the checksums to verify later that the send streams produce correct
+# results.
+$FSSUM_PROG -A -f -w $send_files_dir/1.fssum $SCRATCH_MNT/mysnap1
+$FSSUM_PROG -A -f -w $send_files_dir/2.fssum \
+	-x $SCRATCH_MNT/mysnap2/mysnap1 $SCRATCH_MNT/mysnap2
+
+# Now recreate the filesystem by receiving both send streams and verify we get
+# the same content that the original filesystem had.
+_scratch_unmount
+_scratch_mkfs >>$seqres.full 2>&1
+_scratch_mount
+
+$BTRFS_UTIL_PROG receive -f $send_files_dir/1.snap $SCRATCH_MNT
+$BTRFS_UTIL_PROG receive -f $send_files_dir/2.snap $SCRATCH_MNT
+$FSSUM_PROG -r $send_files_dir/1.fssum $SCRATCH_MNT/mysnap1
+$FSSUM_PROG -r $send_files_dir/2.fssum $SCRATCH_MNT/mysnap2
+
+status=0
+exit

tests/btrfs/191.out

@@ -0,0 +1,19 @@
+QA output created by 191
+wrote 524288/524288 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 524288/524288 bytes at offset 524288
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Create a readonly snapshot of 'SCRATCH_MNT' in 'SCRATCH_MNT/mysnap1'
+At subvol SCRATCH_MNT/mysnap1
+wrote 1048576/1048576 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Create a readonly snapshot of 'SCRATCH_MNT' in 'SCRATCH_MNT/mysnap2'
+deduped 524288/524288 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+deduped 524288/524288 bytes at offset 524288
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+At subvol SCRATCH_MNT/mysnap2
+At subvol mysnap1
+At snapshot mysnap2
+OK
+OK

tests/btrfs/group

@@ -193,3 +193,4 @@
 188 auto quick send prealloc punch
 189 auto quick send clone
 190 auto quick replay balance qgroup
+191 auto quick send dedupe