[PATCH 06/12] btrfs: add simple test of reflink of encrypted data

[Daniel Vacek <neelx@suse.com>]

From: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>

Make sure that we succeed at reflinking encrypted data.

Test deliberately numbered with a high number so it won't conflict with
tests between now and merge.

v1:
    An array overflow bug in btrfs_check_encrypted_read_bio() was hidden
    during fscrypt v6 32/43 patch development until the file size was
    extended to more than 144k (16k + 64k + >64k a.k.a. BTRFS_MAX_BLOCKSIZE
    - it was 33k before).
    We simply needed more pages in the game to run out of the array.

    Even-though the bug was fixed in v7, it may be useful to keep this
    test checking, just to be sure nothing similar happens in the future.

Signed-off-by: Daniel Vacek <neelx@suse.com>
---
 tests/btrfs/613     | 54 +++++++++++++++++++++++++++++++++++++++++++++
 tests/btrfs/613.out | 13 +++++++++++
 2 files changed, 67 insertions(+)
 create mode 100755 tests/btrfs/613
 create mode 100644 tests/btrfs/613.out

diff --git a/tests/btrfs/613 b/tests/btrfs/613
new file mode 100755
index 00000000..fddb9243
--- /dev/null
+++ b/tests/btrfs/613
@@ -0,0 +1,54 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2023 Meta Platforms, Inc.  All Rights Reserved.
+#
+# FS QA Test 613
+#
+# Check if reflinking one encrypted file on btrfs succeeds.
+#
+. ./common/preamble
+_begin_fstest auto encrypt
+
+# Import common functions.
+. ./common/encrypt
+. ./common/filter
+. ./common/reflink
+
+_require_test
+_require_scratch
+_require_cp_reflink
+_require_scratch_encryption -v 2
+_require_command "$KEYCTL_PROG" keyctl
+
+_scratch_mkfs_encrypted &>> $seqres.full
+_scratch_mount
+
+dir=$SCRATCH_MNT/dir
+mkdir $dir
+_set_encpolicy $dir $TEST_KEY_IDENTIFIER
+_add_enckey $SCRATCH_MNT "$TEST_RAW_KEY"
+echo "Creating and reflinking a file"
+$XFS_IO_PROG -t -f -c "pwrite 0 145k" $dir/test > /dev/null
+cp --reflink=always $dir/test $dir/test2
+
+echo "Can't reflink encrypted and unencrypted"
+cp --reflink=always $dir/test $SCRATCH_MNT/fail |& _filter_scratch
+
+echo "Diffing the file and its copy"
+diff $dir/test $dir/test2
+
+echo "Verifying the files are reflinked"
+_verify_reflink $dir/test $dir/test2
+
+echo "Diffing the files after remount"
+_scratch_cycle_mount
+_add_enckey $SCRATCH_MNT "$TEST_RAW_KEY"
+diff $dir/test $dir/test2
+
+echo "Diffing the files after key remove"
+_rm_enckey $SCRATCH_MNT $TEST_KEY_IDENTIFIER
+diff $dir/test $dir/test2 |& _filter_scratch
+
+# success, all done
+status=0
+exit
diff --git a/tests/btrfs/613.out b/tests/btrfs/613.out
new file mode 100644
index 00000000..4895d6dd
--- /dev/null
+++ b/tests/btrfs/613.out
@@ -0,0 +1,13 @@
+QA output created by 613
+Added encryption key with identifier 69b2f6edeee720cce0577937eb8a6751
+Creating and reflinking a file
+Can't reflink encrypted and unencrypted
+cp: failed to clone 'SCRATCH_MNT/fail' from 'SCRATCH_MNT/dir/test': Invalid argument
+Diffing the file and its copy
+Verifying the files are reflinked
+Diffing the files after remount
+Added encryption key with identifier 69b2f6edeee720cce0577937eb8a6751
+Diffing the files after key remove
+Removed encryption key with identifier 69b2f6edeee720cce0577937eb8a6751
+diff: SCRATCH_MNT/dir/test: No such file or directory
+diff: SCRATCH_MNT/dir/test2: No such file or directory
-- 
2.53.0