drbd: Allow larger values for c-fill-target.

Connections through a compressing proxy might have more bits
on the fly. 500MByte instead of 50MByte

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_int.h

@@ -348,7 +348,7 @@ struct p_header80 {
 struct p_header95 {
 	u16	  magic;	/* use DRBD_MAGIC_BIG here */
 	u16	  command;
-	u32	  length;
+	u32	  length;	/* Use only 24 bits of that. Ignore the highest 8 bit. */
 	u8	  payload[0];
 } __packed;
 

include/linux/drbd_limits.h

@@ -143,7 +143,7 @@
 #define DRBD_C_DELAY_TARGET_DEF 10
 
 #define DRBD_C_FILL_TARGET_MIN 0
-#define DRBD_C_FILL_TARGET_MAX 100000
+#define DRBD_C_FILL_TARGET_MAX (1<<20) /* 500MByte in sec */
 #define DRBD_C_FILL_TARGET_DEF 0 /* By default disabled -> controlled by delay_target */
 
 #define DRBD_C_MAX_RATE_MIN     250 /* kByte/sec */