[PATCH] xfs: test libxfs handling of missing RT devices

[Christoph Hellwig <hch@lst.de>]

Test that libxfs rejects initializing a file systems unless in debugger
mode by running xfs_repair and xfs_db with missing arguments.  For
db additionally test that command that require a RT device still do not
work even after libxfs can be initialized using a missing RT device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 tests/xfs/2300     | 48 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/2300.out | 14 ++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100755 tests/xfs/2300
 create mode 100644 tests/xfs/2300.out

diff --git a/tests/xfs/2300 b/tests/xfs/2300
new file mode 100755
index 000000000000..70c1d6bad9cc
--- /dev/null
+++ b/tests/xfs/2300
@@ -0,0 +1,48 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (c) 2026 Christoph Hellwig.
+#
+# FS QA Test No. 2300
+#
+# Tests that repair refuses to work without -r argument, and xfs_db works fine
+# even without it to check libxfs initialization behavior with missing RT
+# devices.
+#
+. ./common/preamble
+_begin_fstest auto quick repair db
+
+. ./common/filter
+
+_cleanup()
+{
+	_unmount $LOOP_MNT 2>/dev/null
+	[ -n "$loop_dev" ] && _destroy_loop_device $loop_dev
+	rm -rf $LOOP_IMG $LOOP_MNT
+	cd /
+	rm -f $tmp.*
+}
+
+_require_scratch_nocheck
+_require_realtime
+
+if [ -z "$SCRATCH_RTDEV" ]; then
+	_notrun "external RT device required"
+fi
+
+_scratch_mkfs >> $seqres.full 2>&1
+
+echo "Dumping superblock using xfs_db without rtdev"
+$XFS_DB_PROG $SCRATCH_DEV -c 'sb 0' -c 'p' >> $seqres.full
+
+echo "Loading RT superblock using xfs_db without rtdev, should fail"
+$XFS_DB_PROG $SCRATCH_DEV -c 'rtsb'
+
+echo "Running xfs_repair -n without rt device, should fail"
+$XFS_REPAIR_PROG -n $SCRATCH_DEV
+
+echo "Running xfs_repair without rt device, should fail"
+$XFS_REPAIR_PROG $SCRATCH_DEV
+
+
+status=0
+exit
diff --git a/tests/xfs/2300.out b/tests/xfs/2300.out
new file mode 100644
index 000000000000..50aab2b83ec9
--- /dev/null
+++ b/tests/xfs/2300.out
@@ -0,0 +1,14 @@
+QA output created by 2300
+Dumping superblock using xfs_db without rtdev
+Loading RT superblock using xfs_db without rtdev, should fail
+realtime device not loaded, use -R.
+Running xfs_repair -n without rt device, should fail
+Phase 1 - find and verify superblock...
+xfs_repair: filesystem has a realtime subvolume
+xfs_repair: realtime device init failed
+xfs_repair: cannot repair this filesystem.  Sorry.
+Running xfs_repair without rt device, should fail
+Phase 1 - find and verify superblock...
+xfs_repair: filesystem has a realtime subvolume
+xfs_repair: realtime device init failed
+xfs_repair: cannot repair this filesystem.  Sorry.
-- 
2.53.0