[PATCH V2 3/3] docs: add more info about target= in disk config

[Jim Fehlig <jfehlig@suse.com>]

target= in disk config can be used to convey arbitrary
configuration information to backends. Add a bit more info
to xl-disk-configuration.txt to clarify this, including some
simple nbd and rbd qdisk configurations.

Signed-off-by: Jim Fehlig <jfehlig@suse.com>
---
 docs/misc/xl-disk-configuration.txt | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/docs/misc/xl-disk-configuration.txt b/docs/misc/xl-disk-configuration.txt
index 29f6ddb..79f1e4a 100644
--- a/docs/misc/xl-disk-configuration.txt
+++ b/docs/misc/xl-disk-configuration.txt
@@ -75,7 +75,15 @@ Special syntax:
    the target was already specified as a positional parameter.  This
    is the only way to specify a target string containing metacharacters
    such as commas and (in some cases) colons, which would otherwise be
-   misinterpreted.
+   misinterpreted. Meta-information in a target string can be used to
+   specify configuration information for a qdisk block backend. For
+   example the nbd and rbd qdisk block backends can be configured with
+
+     target=nbd:192.168.0.1:5555
+     target=rbd:pool/image:mon_host=192.186.0.1\\:6789
+
+   Note that '\' is used to escape metacharacters. Literal backslashes
+   in target= strings must use '\\'.
 
    Future parameter and flag names will start with an ascii letter and
    contain only ascii alphanumerics, hyphens and underscores, and will
-- 
2.1.4