diff -b -r -U 5 --exclude=*.o --exclude=.??* linux-2.4.12-ac3/drivers/md/multipath.c linux-2.4.12-ac3-md/drivers/md/multipath.c
--- linux-2.4.12-ac3/drivers/md/multipath.c	Sun Sep 30 12:26:06 2001
+++ linux-2.4.12-ac3-md/drivers/md/multipath.c	Tue Oct 23 06:12:15 2001
@@ -23,10 +23,11 @@
  */
 
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/raid/multipath.h>
+#include <linux/sysctl.h>
 #include <asm/atomic.h>
 
 #define MAJOR_NR MD_MAJOR
 #define MD_DRIVER
 #define MD_PERSONALITY
@@ -44,17 +45,199 @@
 #define __inline__
 #else
 #define PRINTK(x...)  do { } while (0)
 #endif
 
+static char multipath_version[] =
+		{ "MD/LVM Multipath Storage Device Driver: ver 0.0.1" };
+
+static int multipath_proc_readstr (ctl_table *, int, struct file *, void *,
+		size_t *);
+static int multipath_proc_read_dev (ctl_table *, int, struct file *, void *,
+		size_t *);
+
+static struct ctl_table_header *multipath_table_header;
+
+static struct multipath_dev_table multipath_dev_template = {
+        "",
+	{
+		{MULTIPATH_CONF, "config", NULL, 0, 0444, NULL,
+			&multipath_proc_read_dev},
+		{0},
+	},
+	{{MULTIPATH_DEV, NULL, NULL, 0, 0555, NULL},{0}},
+	{{DEV_MULTIPATH, "multipath", NULL, 0, 0555, NULL},{0}},
+	{{CTL_DEV, "dev", NULL, 0, 0555, NULL},{0}}
+	
+};
+
+static ctl_table multipath_ver_table[] = {
+	{MULTIPATH_VER, "version", &multipath_version,
+		sizeof(multipath_version), 0444, NULL, &multipath_proc_readstr},
+	{0}
+};
+
+static ctl_table multipath_dir_table[] = {
+	{DEV_MULTIPATH, "multipath", NULL, 0, 0555, multipath_ver_table},
+	{0}
+};
+
+static ctl_table multipath_root_table[] = {
+	{CTL_DEV, "dev", NULL, 0, 0555, multipath_dir_table},
+	{0}
+};
 
 static mdk_personality_t multipath_personality;
 static md_spinlock_t retry_list_lock = MD_SPIN_LOCK_UNLOCKED;
 struct multipath_bh *multipath_retry_list = NULL, **multipath_retry_tail;
 
 static int multipath_diskop(mddev_t *mddev, mdp_disk_t **d, int state);
 
+static int multipath_proc_register_dev(mddev_t *md )
+{
+	struct multipath_dev_table *t;
+	multipath_conf_t *conf = mddev_to_conf(md);
+
+	t = &(conf->ctl_tbl);
+
+	memcpy(t, &multipath_dev_template, sizeof(*t));
+
+	/* fill in fields */
+	sprintf( t->mdname, "%d", md->__minor );
+
+	t->dir[0].procname = t->mdname;
+
+	t->md[1].data = md;
+	
+	t->dev[0].child = t->mp;
+	t->mp[0].child = t->dir;
+	t->dir[0].child = t->md;
+	
+	conf->tbl = register_sysctl_table( t->dev, 1 );
+
+	return 0;
+}
+
+static int multipath_proc_unregister_dev( mddev_t *md )
+{
+	multipath_conf_t *conf = mddev_to_conf(md);
+
+	unregister_sysctl_table( conf->tbl );
+
+	return 0;
+} 
+
+
+static int multipath_proc_readstr (ctl_table *tbl, int write, struct file *f,
+		void *buffer, size_t *lenp)
+{
+	int	n;
+
+	if ( write )
+		return -EACCES;		/* readonly string */
+
+		/* check for no or zero length data, or data allready read */
+	if (!tbl->data || !tbl->maxlen || !*lenp || f->f_pos )
+	{
+		*lenp = 0;
+		return 0;
+	}
+	
+	n = strlen(tbl->data);
+
+	if (n > tbl->maxlen)
+		n = tbl->maxlen;
+		
+	if ( n > *lenp )
+		n = *lenp;
+
+	if ( n )
+		if(copy_to_user( buffer, multipath_version, n))
+			return -EFAULT;
+	if ( n  < *lenp )
+	{
+		if(put_user('\n', ((char *)buffer) + n) )
+			return -EFAULT;
+		n++;
+	}
+	*lenp = n;
+	f->f_pos += n;
+
+	return 0;
+}
+
+static int multipath_proc_read_dev (ctl_table *t, int w, struct file *f,
+		void *b, size_t *s)
+{
+	mddev_t			*md;
+	multipath_conf_t	*conf;
+	struct multipath_info	*info;
+	int			path, len, i;
+#define LEN_HDR 48
+#define LEN_DSK 85
+
+	if (!t->data || !*s || f->f_pos )
+	{
+		*s = 0;
+		return 0;
+	}
+
+	if ( w )
+		return -EACCES;		/* readonly */
+
+	md = t->data;
+	conf = mddev_to_conf( md );
+
+	if ( f->f_pos == 0 )
+	{
+		if ( *s < LEN_HDR )	/* must be big enough to handle the */
+			return -EFAULT;	/* size of the next sprintf */
+
+		sprintf( b, "nr_disks %3d: raid_disks %3d: working_disks %3d\n",
+			conf->nr_disks&255, conf->raid_disks&255,
+			conf->working_disks&255 );
+
+		len = strlen( b );
+		if ( *s < len )	/* check for overflow */
+			return -EFAULT;
+
+		if ( *s < len + LEN_DSK )
+		{
+			*s = len;
+			f->f_pos = len;
+			return 0;
+		}
+	}
+
+
+	for ( path = 0; path < conf->nr_disks; path++ )
+	{
+		info = &conf->multipaths[path];
+
+		sprintf( b + len,
+			"%3d: disk %3d: dev %3d.%3d\n"
+			"\tworking %c: write only %c: spare %c: used %c "
+			"ops %10d\n",
+			info->number&255, info->raid_disk&255, MAJOR(info->dev),
+			MINOR(info->dev),
+			info->operational? 'y' : 'n',
+			info->write_only? 'y' : 'n',
+			info->spare? 'y' : 'n',
+			info->used_slot? 'y' : 'n',
+			info->nr_ops );
+		len = strlen( b );
+		if ( *s < len + LEN_DSK )
+			break;
+	}
+
+	*s = len;
+	f->f_pos = len;
+	return 0;
+#undef LEN_HDR
+#undef LEN_DSK
+}
+
 struct buffer_head *multipath_alloc_bh(multipath_conf_t *conf, int cnt)
 {
 	/* return a linked list of "cnt" struct buffer_heads.
 	 * don't take any off the free list unless we know we can
 	 * get all we need, otherwise we could deadlock
@@ -373,10 +556,11 @@
  * degrades dramatically because position is multipath, not device based.
  * This should be changed to be device based. Also atomic sequential
  * reads should be somehow balanced.
  */
 
+
 static int multipath_read_balance (multipath_conf_t *conf)
 {
 	int disk;
 
 	for (disk = 0; disk < conf->raid_disks; disk++)	
@@ -444,10 +628,13 @@
 	bh_req->b_rdev = multipath->dev;
 /*	bh_req->b_rsector = bh->n_rsector; */
 	bh_req->b_end_io = multipath_end_request;
 	bh_req->b_private = r1_bh;
 	generic_make_request (rw, bh_req);
+
+	multipath->nr_ops++;
+
 	return 0;
 }
 
 static int multipath_status (char *page, mddev_t *mddev)
 {
@@ -1036,10 +1223,16 @@
 		printk(MEM_ERROR, mdidx(mddev));
 		goto out;
 	}
 	memset(conf, 0, sizeof(*conf));
 
+	if (multipath_proc_register_dev( mddev ))
+	{
+		printk(ERRORS, mdidx(mddev));
+		goto out_free_conf;
+	}
+
 	ITERATE_RDEV(mddev,rdev,tmp) {
 		if (rdev->faulty) {
 			/* this is a "should never happen" case and if it */
 			/* ever does happen, a continue; won't help */
 			printk(ERRORS, partition_name(rdev->dev));
@@ -1224,10 +1417,11 @@
 
 static int multipath_stop (mddev_t *mddev)
 {
 	multipath_conf_t *conf = mddev_to_conf(mddev);
 
+	multipath_proc_unregister_dev( mddev );
 	md_unregister_thread(conf->thread);
 	multipath_shrink_mpbh(conf);
 	multipath_shrink_bh(conf, conf->freebh_cnt);
 	kfree(conf);
 	mddev->private = NULL;
@@ -1246,15 +1440,19 @@
 	diskop:		multipath_diskop,
 };
 
 static int md__init multipath_init (void)
 {
+	multipath_table_header = register_sysctl_table(multipath_root_table, 1);
+
 	return register_md_personality (MULTIPATH, &multipath_personality);
 }
 
 static void multipath_exit (void)
 {
+	unregister_sysctl_table(multipath_table_header);
+
 	unregister_md_personality (MULTIPATH);
 }
 
 module_init(multipath_init);
 module_exit(multipath_exit);
diff -b -r -U 5 --exclude=*.o --exclude=.??* linux-2.4.12-ac3/include/linux/raid/multipath.h linux-2.4.12-ac3-md/include/linux/raid/multipath.h
--- linux-2.4.12-ac3/include/linux/raid/multipath.h	Fri Sep 14 14:22:18 2001
+++ linux-2.4.12-ac3-md/include/linux/raid/multipath.h	Tue Oct 23 06:11:44 2001
@@ -1,9 +1,18 @@
 #ifndef _MULTIPATH_H
 #define _MULTIPATH_H
 
 #include <linux/raid/md.h>
+#include <linux/sysctl.h>
+
+struct multipath_dev_table {
+	char		mdname[8];
+	ctl_table	md[3];
+	ctl_table	dir[2];
+	ctl_table	mp[2];
+	ctl_table	dev[2];
+};
 
 struct multipath_info {
 	int		number;
 	int		raid_disk;
 	kdev_t		dev;
@@ -16,10 +25,11 @@
 	int		operational;
 	int		write_only;
 	int		spare;
 
 	int		used_slot;
+	unsigned int		nr_ops;
 };
 
 struct multipath_private_data {
 	mddev_t			*mddev;
 	struct multipath_info	multipaths[MD_SB_DISKS];
@@ -50,10 +60,13 @@
 	int	phase;
 	int	window;
 	md_wait_queue_head_t	wait_done;
 	md_wait_queue_head_t	wait_ready;
 	md_spinlock_t		segment_lock;
+	int	last;		/* last used, or prefered route */
+	struct ctl_table_header	*tbl;
+	struct multipath_dev_table	ctl_tbl;
 };
 
 typedef struct multipath_private_data multipath_conf_t;
 
 /*
diff -b -r -U 5 --exclude=*.o --exclude=.??* linux-2.4.12-ac3/include/linux/sysctl.h linux-2.4.12-ac3-md/include/linux/sysctl.h
--- linux-2.4.12-ac3/include/linux/sysctl.h	Tue Oct 23 04:56:06 2001
+++ linux-2.4.12-ac3-md/include/linux/sysctl.h	Tue Oct 23 04:26:42 2001
@@ -554,11 +554,12 @@
 enum {
 	DEV_CDROM=1,
 	DEV_HWMON=2,
 	DEV_PARPORT=3,
 	DEV_RAID=4,
-	DEV_MAC_HID=5
+	DEV_MAC_HID=5,
+	DEV_MULTIPATH=6
 };
 
 /* /proc/sys/dev/cdrom */
 enum {
 	DEV_CDROM_INFO=1,
@@ -576,10 +577,22 @@
 
 /* /proc/sys/dev/raid */
 enum {
 	DEV_RAID_SPEED_LIMIT_MIN=1,
 	DEV_RAID_SPEED_LIMIT_MAX=2
+};
+
+/* /proc/sys/dev/multipath */
+enum {
+	MULTIPATH_VER=1,
+	MULTIPATH_DEV=2
+};
+
+/* /proc/sys/dev/multipath/md n */
+enum {
+	MULTIPATH_ROUTING=1,
+	MULTIPATH_CONF=2
 };
 
 /* /proc/sys/dev/parport/default */
 enum {
 	DEV_PARPORT_DEFAULT_TIMESLICE=1,