[Xen-changelog] [xen-unstable] interface: add 'discard-secure' and BLKIF_DISCARD_SECURE

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
# Date 1319727888 -3600
# Node ID 7536987fbad83785d8168ce120d3039a69c4a1f9
# Parent  083797fda372341278757b5e23db6de0862c4242
interface: add 'discard-secure' and BLKIF_DISCARD_SECURE

Alter the 'reserved' uint8_t to be used a 'flag'. We use only for one
flag: BLKIF_DISCARD_SECURE.

That flag can only be set if the backend has set 'discard-secure' to
one.  If backend has not set 'discard-secure' to one, that flag will
have no effect.

Acked-by: Jan Beulich <JBeulich@xxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Committed-by: Keir Fraser <keir@xxxxxxx>
---


diff -r 083797fda372 -r 7536987fbad8 xen/include/public/io/blkif.h
--- a/xen/include/public/io/blkif.h     Thu Oct 27 16:04:17 2011 +0100
+++ b/xen/include/public/io/blkif.h     Thu Oct 27 16:04:48 2011 +0100
@@ -120,6 +120,9 @@
  * allocation unit in bytes if reported by the device. Otherwise the
  * discard-granularity will be set to match the device's physical block size.
  * It is the minimum size you can discard.
+ * 'discard-secure' - All copies of the discarded sectors (potentially created
+ * by garbage collection) must also be erased.  To use this feature, the flag
+ * BLKIF_DISCARD_SECURE must be set in the blkif_request_discard.
  */
 #define BLKIF_OP_DISCARD           5
 
@@ -160,7 +163,8 @@
  */
 struct blkif_request_discard {
     uint8_t        operation;    /* BLKIF_OP_DISCARD                     */
-    uint8_t        reserved;     /*                                      */
+    uint8_t        flag;         /* BLKIF_DISCARD_SECURE or zero         */
+#define BLKIF_DISCARD_SECURE (1<<0)  /* ignored if discard-secure=0      */
     blkif_vdev_t   handle;       /* same as for read/write requests      */
     uint64_t       id;           /* private guest value, echoed in resp  */
     blkif_sector_t sector_number;/* start sector idx on disk             */

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