[PATCH v2 6/6] tools/virtiofsd: xattr name mapping examples

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Add a few examples of xattrmaps to the documentation.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 docs/tools/virtiofsd.rst | 49 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst
index 2efa16d3c5..a138549862 100644
--- a/docs/tools/virtiofsd.rst
+++ b/docs/tools/virtiofsd.rst
@@ -161,6 +161,55 @@ in which case a 'server' rule will always match on all names from
 the server.
 
 
+xattr-mapping Examples
+----------------------
+
+1) Prefix all attributes with 'user.virtiofs.'
+
+::
+
+-o xattrmap=":all:prefix::user.virtiofs.::all:bad:::"
+
+
+This uses two rules, using : as the field separator;
+the first rule prefixes and strips 'user.virtiofs.',
+the second rule hides any non-prefixed attributes that
+the host set.
+
+2) Prefix 'trusted.' attributes, allow others through
+
+::
+
+   "/all/prefix/trusted./user.virtiofs./
+    /server/bad//trusted./
+    /client/bad/user.virtiofs.trusted.//
+    /all/ok///"
+
+
+Here there are four rules, using / as the field
+separator, and also demonstrating that new lines can
+be included between rules.
+The first rule is the prefixing of 'trusted.'.
+The second rule hides unprefixed 'trusted.' attributes
+on the host.
+The third rule stops a guest from explicitily setting
+the 'user.viritofs.trusted.' path directly.
+Finally, the fourth rule lets all remaining attributes
+through.
+
+3) Hide 'security.' attributes, and allow everything else
+
+::
+
+    "/all/bad/security./security./
+     /all/ok///'
+
+The first rule combines what could be separate client and server
+rules into a single 'all' rule, matching 'security.' in either
+client arguments or lists returned from the host.  This stops
+the client seeing any 'security.' attributes on the server and
+stops it setting  any.
+
 Examples
 --------
 
-- 
2.26.2