[PATCH] xfs/841: create a block device that must exist

[Christoph Hellwig <hch@lst.de>]

This test currently creates a block device node for /dev/ram0,
which isn't guaranteed to exist, and can thus cause the test to
fail with:

mkfs.xfs: cannot open $TEST_DIR/proto/blockdev: No such device or address

Instead, create a node for the backing device for $TEST_DIR, which must
exist.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 tests/xfs/841 | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tests/xfs/841 b/tests/xfs/841
index ee2368d4a746..ddb1b3bea104 100755
--- a/tests/xfs/841
+++ b/tests/xfs/841
@@ -85,9 +85,12 @@ _create_proto_dir()
 	$here/src/af_unix "$PROTO_DIR/socket" 2> /dev/null || true
 
 	# Block device (requires root)
-	mknod "$PROTO_DIR/blockdev" b 1 0 2> /dev/null || true
+	# Uses the device for $TEST_DIR to ensure it always exists.
+	mknod "$PROTO_DIR/blockdev" b $(stat -c '%Hd %Ld' $TEST_DIR) \
+		2> /dev/null || true
 
 	# Character device (requires root)
+	# Uses /dev/null, which should always exist
 	mknod "$PROTO_DIR/chardev" c 1 3 2> /dev/null || true
 }
 
-- 
2.47.3