diff -urN lvm/drivers/md/lvm.c lvm-fix/drivers/md/lvm.c
--- lvm/drivers/md/lvm.c	Thu Oct  4 18:51:34 2001
+++ lvm-fix/drivers/md/lvm.c	Thu Oct  4 18:51:48 2001
@@ -259,9 +259,13 @@
 
 #include "lvm-internal.h"
 
-#define	LVM_CORRECT_READ_AHEAD( a) \
-   if      ( a < LVM_MIN_READ_AHEAD || \
-             a > LVM_MAX_READ_AHEAD) a = LVM_MAX_READ_AHEAD;
+#define	LVM_CORRECT_READ_AHEAD(a)		\
+do {						\
+	if ((a) < LVM_MIN_READ_AHEAD ||		\
+	    (a) > LVM_MAX_READ_AHEAD)		\
+		(a) = LVM_DEFAULT_READ_AHEAD;	\
+	read_ahead[MAJOR_NR] = (a);		\
+} while(0)
 
 #ifndef WRITEA
 #  define WRITEA WRITE
@@ -414,17 +418,13 @@
 
 static struct gendisk lvm_gendisk =
 {
-	MAJOR_NR,		/* major # */
-	LVM_NAME,		/* name of major */
-	0,			/* number of times minor is shifted
-				   to get real minor */
-	1,			/* maximum partitions per device */
-	lvm_hd_struct,		/* partition table */
-	lvm_size,		/* device size in blocks, copied
-				   to block_size[] */
-	MAX_LV,			/* number or real devices */
-	NULL,			/* internal */
-	NULL,			/* pointer to next gendisk struct (internal) */
+	major:		MAJOR_NR,
+	major_name:	LVM_NAME,
+	minor_shift:	0,
+	max_p:		1,
+	part:		lvm_hd_struct,
+	sizes:		lvm_size,
+	nr_real:	MAX_LV,
 };
 
 /*
@@ -939,6 +939,11 @@
 			return -EFAULT;
 		break;
 
+	case BLKGETSIZE64:
+		if (put_user((u64)lv_ptr->lv_size << 9, (u64 *)arg))
+			return -EFAULT;
+		break;
+
 
 	case BLKFLSBUF:
 		/* flush buffer cache */
@@ -962,6 +967,7 @@
 		    (long) arg > LVM_MAX_READ_AHEAD)
 			return -EINVAL;
 		lv_ptr->lv_read_ahead = (long) arg;
+		read_ahead[MAJOR_NR] = lv_ptr->lv_read_ahead;
 		break;
 
 
diff -urN lvm/include/linux/lvm.h lvm-fix/include/linux/lvm.h
--- lvm/include/linux/lvm.h	Thu Oct  4 18:51:34 2001
+++ lvm-fix/include/linux/lvm.h	Thu Oct  4 18:51:48 2001
@@ -260,8 +260,9 @@
 #define	LVM_MAX_STRIPES		128	/* max # of stripes */
 #define	LVM_MAX_SIZE            ( 1024LU * 1024 / SECTOR_SIZE * 1024 * 1024)	/* 1TB[sectors] */
 #define	LVM_MAX_MIRRORS    	2	/* future use */
-#define	LVM_MIN_READ_AHEAD	2	/* minimum read ahead sectors */
-#define	LVM_MAX_READ_AHEAD	120	/* maximum read ahead sectors */
+#define	LVM_MIN_READ_AHEAD	0	/* minimum read ahead sectors */
+#define	LVM_DEFAULT_READ_AHEAD	1024	/* default read ahead sectors for 512k scsi segments */
+#define	LVM_MAX_READ_AHEAD	10000	/* maximum read ahead sectors */
 #define	LVM_MAX_LV_IO_TIMEOUT	60	/* seconds I/O timeout (future use) */
 #define	LVM_PARTITION           0xfe	/* LVM partition id */
 #define	LVM_NEW_PARTITION       0x8e	/* new LVM partition id (10/09/1999) */