[PATCH v2] fstests: btrfs: test setting compression via xattr on nodatacow files

[Chung-Chiang Cheng <cccheng@synology.com>]

Compression and nodatacow are mutually exclusive. Besides ioctl, there
is another way to setting compression via xattrs, and shouldn't produce
invalid combinations.

Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com>
---
 tests/btrfs/264     | 90 +++++++++++++++++++++++++++++++++++++++++++++
 tests/btrfs/264.out | 11 ++++++
 2 files changed, 101 insertions(+)
 create mode 100755 tests/btrfs/264
 create mode 100644 tests/btrfs/264.out

diff --git a/tests/btrfs/264 b/tests/btrfs/264
new file mode 100755
index 00000000..bb11116c
--- /dev/null
+++ b/tests/btrfs/264
@@ -0,0 +1,90 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2022 Synology Inc. All Rights Reserved.
+#
+# FS QA Test No. 264
+#
+# Compression and nodatacow are mutually exclusive. Besides ioctl, there
+# is another way to setting compression via xattrs, and shouldn't produce
+# invalid combinations.
+#
+# To prevent mix any compression-related options with nodatacow, FS_NOCOMP_FL
+# is also rejected by ioctl as well as FS_COMPR_FL on nodatacow files. To
+# align with it, no and none are also unacceptable in this test.
+#
+# The regression is fixed by a patch with the following subject:
+#   btrfs: do not allow compression on nodatacow files
+#
+. ./common/preamble
+_begin_fstest auto quick compress attr
+
+# Import common functions.
+. ./common/filter
+. ./common/attr
+
+# real QA test starts here
+
+_supported_fs btrfs
+_require_scratch
+_require_attrs
+
+_scratch_mkfs >>$seqres.full 2>&1
+_scratch_mount
+
+set_compression() # $1: filename, $2: alg
+{
+	[ -f "$1" ] || return
+	$SETFATTR_PROG -n "btrfs.compression" -v "$2" "$1" |& _filter_scratch
+}
+
+# FS_NOCOMP_FL bit isn't recognized by chattr/lsattr before e2fsprogs 1.46.2
+# In order to make this test available with an older version, we wrap the output
+# of lsattr to distinguish FS_COMP_FL and FS_NOCOMP_FL
+check_compression() # $1: filename
+{
+	$LSATTR_PROG -l "$1" | grep -q "Compression_Requested"
+
+	if [ $? -eq 0 ]; then
+		echo "$1: Compression is set" | _filter_scratch
+	else
+		echo "$1: Compression is not set" | _filter_scratch
+	fi
+}
+
+#
+# DATACOW
+#
+test_file="$SCRATCH_MNT/foo"
+touch "$test_file"
+$CHATTR_PROG -C "$test_file"
+
+set_compression "$test_file" zlib
+check_compression "$test_file"
+set_compression "$test_file" no
+check_compression "$test_file"
+set_compression "$test_file" lzo
+check_compression "$test_file"
+set_compression "$test_file" none
+check_compression "$test_file"
+set_compression "$test_file" zstd
+check_compression "$test_file"
+
+#
+# NODATACOW
+#
+test_file="$SCRATCH_MNT/bar"
+touch "$test_file"
+$CHATTR_PROG +C "$test_file"
+
+# all valid compression type are not allowed on nodatacow files
+set_compression "$test_file" zlib
+set_compression "$test_file" lzo
+set_compression "$test_file" zstd
+
+# no/none are also not allowed on nodatacow files
+set_compression "$test_file" no
+set_compression "$test_file" none
+
+# success, all done
+status=0
+exit
diff --git a/tests/btrfs/264.out b/tests/btrfs/264.out
new file mode 100644
index 00000000..7dd36054
--- /dev/null
+++ b/tests/btrfs/264.out
@@ -0,0 +1,11 @@
+QA output created by 264
+SCRATCH_MNT/foo: Compression is set
+SCRATCH_MNT/foo: Compression is not set
+SCRATCH_MNT/foo: Compression is set
+SCRATCH_MNT/foo: Compression is not set
+SCRATCH_MNT/foo: Compression is set
+setfattr: SCRATCH_MNT/bar: Invalid argument
+setfattr: SCRATCH_MNT/bar: Invalid argument
+setfattr: SCRATCH_MNT/bar: Invalid argument
+setfattr: SCRATCH_MNT/bar: Invalid argument
+setfattr: SCRATCH_MNT/bar: Invalid argument
-- 
2.25.1