[PATCH 2/3] fstests: add helper _require_xfs_io_shutdown

[Amir Goldstein <amir73il@gmail.com>]

Requirements for tests that shutdown fs using "xfs_io -c shutdown".
The requirements are stricter than the requirement for tests that
shutdown fs using _scratch_shutdown helper.

Generally, with overlay fs, tests can do _scratch_shutdown, but not
xfs_io -c shutdown.

Encode this stricter requirement in helper _require_xfs_io_shutdown
and use it in test generic/623, to express that it cannot run on
overalyfs.

Reported-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/linux-fsdevel/20250521-ovl_ro-v1-1-2350b1493d94@igalia.com/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 common/rc         | 21 +++++++++++++++++++++
 tests/generic/623 |  2 +-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/common/rc b/common/rc
index d9a8b52e..21899a4a 100644
--- a/common/rc
+++ b/common/rc
@@ -616,6 +616,27 @@ _scratch_shutdown_and_syncfs()
 	fi
 }
 
+# Requirements for tests that shutdown fs using "xfs_io -c shutdown".
+# The requirements are stricter than the requirement for tests that
+# shutdown fs using _scratch_shutdown helper.
+# Generally, with overlay fs, test can do _scratch_shutdown, but not
+# xfs_io -c shutdown.
+# It is possible, but not trivial, to execute "xfs_io -c shutdown" as part
+# of a command sequence when shutdown ioctl is to be performed on the base fs
+# (i.e. on an alternative _scratch_shutdown_handle path) as the example code
+# in _scratch_shutdown_and_syncfs() does.
+# A test that open codes this pattern can relax the _require_xfs_io_shutdown
+# requirement down to _require_scratch_shutdown.
+_require_xfs_io_shutdown()
+{
+	if [ _scratch_shutdown_handle != $SCRATCH_MNT ]; then
+		# Most likely overlayfs
+		_notrun "xfs_io -c shutdown not supported on $FSTYP"
+	fi
+	_require_xfs_io_command "shutdown"
+	_require_scratch_shutdown
+}
+
 _move_mount()
 {
 	local mnt=$1
diff --git a/tests/generic/623 b/tests/generic/623
index b97e2adb..f546d529 100755
--- a/tests/generic/623
+++ b/tests/generic/623
@@ -15,7 +15,7 @@ _begin_fstest auto quick shutdown mmap
 	"xfs: restore shutdown check in mapped write fault path"
 
 _require_scratch_nocheck
-_require_scratch_shutdown
+_require_xfs_io_shutdown
 
 _scratch_mkfs &>> $seqres.full
 _scratch_mount
-- 
2.34.1