[PATCH] dm: ioctl: add noflush suspend

Provide a dm ioctl option to request noflush suspending.  (See next patch for
what this is for.) As the interface is extended, the version number is
incremented.

Other than accepting the new option through the interface, There is no change
to existing behaviour.

Test results:
Confirmed the option is given from user-space correctly.
Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Cc: dm-devel@redhat.com
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/md/dm-ioctl.c

@@ -774,6 +774,8 @@ static int do_suspend(struct dm_ioctl *param)
 
 	if (param->flags & DM_SKIP_LOCKFS_FLAG)
 		suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
+	if (param->flags & DM_NOFLUSH_FLAG)
+		suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
 
 	if (!dm_suspended(md))
 		r = dm_suspend(md, suspend_flags);
@@ -815,6 +817,8 @@ static int do_resume(struct dm_ioctl *param)
 		/* Suspend if it isn't already suspended */
 		if (param->flags & DM_SKIP_LOCKFS_FLAG)
 			suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
+		if (param->flags & DM_NOFLUSH_FLAG)
+			suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
 		if (!dm_suspended(md))
 			dm_suspend(md, suspend_flags);
 

drivers/md/dm.h

@@ -47,6 +47,7 @@
  * Suspend feature flags
  */
 #define DM_SUSPEND_LOCKFS_FLAG		(1 << 0)
+#define DM_SUSPEND_NOFLUSH_FLAG		(1 << 1)
 
 /*
  * List of devices that a metadevice uses and should open/close.

include/linux/dm-ioctl.h

@@ -285,9 +285,9 @@ typedef char ioctl_struct[308];
 #define DM_DEV_SET_GEOMETRY	_IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
 
 #define DM_VERSION_MAJOR	4
-#define DM_VERSION_MINOR	10
+#define DM_VERSION_MINOR	11
 #define DM_VERSION_PATCHLEVEL	0
-#define DM_VERSION_EXTRA	"-ioctl (2006-09-14)"
+#define DM_VERSION_EXTRA	"-ioctl (2006-10-12)"
 
 /* Status bits */
 #define DM_READONLY_FLAG	(1 << 0) /* In/Out */
@@ -323,4 +323,9 @@ typedef char ioctl_struct[308];
  */
 #define DM_SKIP_LOCKFS_FLAG	(1 << 10) /* In */
 
+/*
+ * Set this to suspend without flushing queued ios.
+ */
+#define DM_NOFLUSH_FLAG		(1 << 11) /* In */
+
 #endif				/* _LINUX_DM_IOCTL_H */