[PATCH 1/2] btrfs: test incremental send after a succession of rename and link operations

[fdmanana@kernel.org]

From: Filipe Manana <fdmanana@suse.com>

Test that an incremental send operation emits the correct path for link
and rename operation after swapping the names and locations of several
inodes in a way that creates a nasty dependency of rename and link
operations. Notably one file has its name and location swapped with a
directory for which it used to have a directory entry in it.

This test currently fails but a kernel patch for it exists and has the
following subject:

  "btrfs: send, orphanize first all conflicting inodes when processing references"

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 tests/btrfs/221     | 119 ++++++++++++++++++++++++++++++++++++++++++++
 tests/btrfs/221.out |   6 +++
 tests/btrfs/group   |   1 +
 3 files changed, 126 insertions(+)
 create mode 100755 tests/btrfs/221
 create mode 100644 tests/btrfs/221.out

diff --git a/tests/btrfs/221 b/tests/btrfs/221
new file mode 100755
index 00000000..a482d0c5
--- /dev/null
+++ b/tests/btrfs/221
@@ -0,0 +1,119 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2020 SUSE Linux Products GmbH. All Rights Reserved.
+#
+# FS QA Test No. btrfs/221
+#
+# Test that an incremental send operation emits the correct path for link and
+# rename operation after swapping the names and locations of several inodes in
+# a way that creates a nasty dependency of rename and link operations. Notably
+# one file has its name and location swapped with a directory for which it used
+# to have a directory entry in it.
+#
+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 $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# real QA test starts here
+_supported_fs btrfs
+_require_test
+_require_scratch
+_require_fssum
+
+send_files_dir=$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
+
+touch $SCRATCH_MNT/a
+touch $SCRATCH_MNT/b
+mkdir $SCRATCH_MNT/testdir
+# We want "a" to have a lower inode number than its parent directory, so it
+# was created before the directory and then moved into it.
+mv $SCRATCH_MNT/a $SCRATCH_MNT/testdir/a
+
+# Filesystem looks like:
+#
+# .                                                      (ino 256)
+# |----- testdir/                                        (ino 259)
+# |          |----- a                                    (ino 257)
+# |
+# |----- b                                               (ino 258)
+#
+$BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT \
+	$SCRATCH_MNT/mysnap1 > /dev/null
+
+$BTRFS_UTIL_PROG send -f $send_files_dir/1.snap \
+	$SCRATCH_MNT/mysnap1 2>&1 1>/dev/null | _filter_scratch
+
+# Now rename 259 to "testdir_2", then change the name of 257 to "testdir" and
+# make it a direct descendant of the root inode (256). Also create a new link
+# for inode 257 with the old name of inode 258. By swapping the names and
+# location of several inodes and create a nasty dependency chain of rename and
+# link operations.
+mv $SCRATCH_MNT/testdir/a $SCRATCH_MNT/a2
+touch $SCRATCH_MNT/testdir/a
+mv $SCRATCH_MNT/b $SCRATCH_MNT/b2
+ln $SCRATCH_MNT/a2 $SCRATCH_MNT/b
+mv $SCRATCH_MNT/testdir $SCRATCH_MNT/testdir_2
+mv $SCRATCH_MNT/a2 $SCRATCH_MNT/testdir
+
+# Filesystem now looks like:
+#
+# .                                                      (ino 256)
+# |----- testdir_2/                                      (ino 259)
+# |          |----- a                                    (ino 260)
+# |
+# |----- testdir                                         (ino 257)
+# |----- b                                               (ino 257)
+# |----- b2                                              (ino 258)
+#
+
+$BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT \
+		 $SCRATCH_MNT/mysnap2 > /dev/null
+$BTRFS_UTIL_PROG send -p $SCRATCH_MNT/mysnap1 -f $send_files_dir/2.snap \
+		 $SCRATCH_MNT/mysnap2 2>&1 1>/dev/null | _filter_scratch
+
+$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 $SCRATCH_MNT > /dev/null
+
+# The receive operation below used to fail because when attemping to create the
+# hard link named "b" for inode 257, the link operation contained a target path
+# of "o259-6-0/a", which caused the receiver process to fail because inode 259
+# was not yet orphanized (renamed to "o259-6-0"), it still had the name "testdir"
+# when the link operation was issued.
+$BTRFS_UTIL_PROG receive -f $send_files_dir/2.snap $SCRATCH_MNT > /dev/null
+
+$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
diff --git a/tests/btrfs/221.out b/tests/btrfs/221.out
new file mode 100644
index 00000000..4c887062
--- /dev/null
+++ b/tests/btrfs/221.out
@@ -0,0 +1,6 @@
+QA output created by 221
+At subvol SCRATCH_MNT/mysnap1
+At subvol SCRATCH_MNT/mysnap2
+At subvol mysnap1
+OK
+OK
diff --git a/tests/btrfs/group b/tests/btrfs/group
index 1b5fa695..8b285dbb 100644
--- a/tests/btrfs/group
+++ b/tests/btrfs/group
@@ -222,3 +222,4 @@
 218 auto quick volume
 219 auto quick volume
 220 auto quick
+221 auto quick send
-- 
2.26.2