dm thin: add pool target flags to control discard

[firefly-linux-kernel-4.4.55.git] / Documentation / device-mapper / thin-provisioning.txt

diff --git a/Documentation/device-mapper/thin-provisioning.txt b/Documentation/device-mapper/thin-provisioning.txt
index 310c1201d621cc308fffc549d3135ec295d1ca27..3370bc4d7b9885b45040b359d858f4112418b74f 100644 (file)
--- a/Documentation/device-mapper/thin-provisioning.txt
+++ b/Documentation/device-mapper/thin-provisioning.txt
@@ -223,7 +223,13 @@ i) Constructor
              <low water mark (blocks)> [<number of feature args> [<arg>]*]
 
     Optional feature arguments:
-    - 'skip_block_zeroing': skips the zeroing of newly-provisioned blocks.
+
+      skip_block_zeroing: Skip the zeroing of newly-provisioned blocks.
+
+      ignore_discard: Disable discard support.
+
+      no_discard_passdown: Don't pass discards down to the underlying
+                          data device, but just remove the mapping.
 
     Data block size must be between 64KB (128 sectors) and 1GB
     (2097152 sectors) inclusive.