Re: [PATCH v4 1/3] xfstests: btrfs: add functions to create dm-error device

quoted

+# this test requires the device mapper error target
+#
+_require_dmerror()
+{
+    _require_command "$DMSETUP_PROG" dmsetup
+
+    $DMSETUP_PROG targets | grep error >/dev/null 2>&1
+    if [ $? -eq 0 ]
+    then
+       :
+    else
+       _notrun "This test requires dm error support"
+    fi

Why not just:

[ $? -ne 0 ] && _notrun "This test requires dm error support"

The empty branch doesn't make much sense.

  yes.

Also, please indent the body of this function using an 8 spaces tab,
which is the official style for fstests (just look at the surrounding
functions for example).

  not sure how this got slipped. I am fixing it.

Other than that, it looks good to me. You can add:

Reviewed-by: Filipe Manana <redacted>

Thanks.
Anand