1 files changed, 7 insertions, 2 deletions

diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt
index 68c0f517c60e..82960cffbad3 100644
--- a/Documentation/device-mapper/cache.txt
+++ b/Documentation/device-mapper/cache.txt
@@ -221,6 +221,7 @@ Status
 <#read hits> <#read misses> <#write hits> <#write misses>
 <#demotions> <#promotions> <#dirty> <#features> <features>*
 <#core args> <core args>* <policy name> <#policy args> <policy args>*
+<cache metadata mode>
 
 metadata block size      : Fixed block size for each metadata block in
                              sectors
@@ -251,8 +252,12 @@ core args		 : Key/value pairs for tuning the core
                              e.g. migration_threshold
 policy name              : Name of the policy
 #policy args             : Number of policy arguments to follow (must be even)
-policy args              : Key/value pairs
-                             e.g. sequential_threshold
+policy args              : Key/value pairs e.g. sequential_threshold
+cache metadata mode      : ro if read-only, rw if read-write
+        In serious cases where even a read-only mode is deemed unsafe
+        no further I/O will be permitted and the status will just
+        contain the string 'Fail'.  The userspace recovery tools
+        should then be used.
 
 Messages
 --------