[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: Kiyoshi Ueda <[e-mail]>
Signed-off-by: Jun'ichi Nomura <[e-mail]>
Signed-off-by: Alasdair G Kergon <[e-mail]>
Cc: [e-mail]
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/md/dm-ioctl.c

···
 
 	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);
···
 		/* 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

···
  * 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

···
 #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 */
···
  * Set this to avoid attempting to freeze any filesystem when suspending.
  */
 #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 */