Index: lib/libstand/cd9660.c
===================================================================
--- lib/libstand/cd9660.c
+++ lib/libstand/cd9660.c
@@ -143,7 +143,7 @@
 		if (bcmp(sh->type, SUSP_CONTINUATION, 2) == 0) {
 			shc = (ISO_RRIP_CONT *)sh;
 			error = f->f_dev->dv_strategy(f->f_devdata, F_READ,
-			    cdb2devb(isonum_733(shc->location)),
+			    cdb2devb(isonum_733(shc->location)), 0,
 			    ISO_DEFAULT_BLOCK_SIZE, susp_buffer, &read);
 
 			/* Bail if it fails. */
@@ -288,7 +288,7 @@
 	for (bno = 16;; bno++) {
 		twiddle(1);
 		rc = f->f_dev->dv_strategy(f->f_devdata, F_READ, cdb2devb(bno),
-					   ISO_DEFAULT_BLOCK_SIZE, buf, &read);
+					0, ISO_DEFAULT_BLOCK_SIZE, buf, &read);
 		if (rc)
 			goto out;
 		if (read != ISO_DEFAULT_BLOCK_SIZE) {
@@ -322,7 +322,7 @@
 				twiddle(1);
 				rc = f->f_dev->dv_strategy
 					(f->f_devdata, F_READ,
-					 cdb2devb(bno + boff),
+					 cdb2devb(bno + boff), 0,
 					 ISO_DEFAULT_BLOCK_SIZE,
 					 buf, &read);
 				if (rc)
@@ -381,7 +381,7 @@
 		bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
 		twiddle(1);
 		rc = f->f_dev->dv_strategy(f->f_devdata, F_READ, cdb2devb(bno),
-		    ISO_DEFAULT_BLOCK_SIZE, buf, &read);
+		    0, ISO_DEFAULT_BLOCK_SIZE, buf, &read);
 		if (rc)
 			goto out;
 		if (read != ISO_DEFAULT_BLOCK_SIZE) {
@@ -438,7 +438,8 @@
 
 		twiddle(16);
 		rc = f->f_dev->dv_strategy(f->f_devdata, F_READ,
-		    cdb2devb(blkno), ISO_DEFAULT_BLOCK_SIZE, fp->f_buf, &read);
+		    cdb2devb(blkno), 0, ISO_DEFAULT_BLOCK_SIZE,
+		    fp->f_buf, &read);
 		if (rc)
 			return (rc);
 		if (read != ISO_DEFAULT_BLOCK_SIZE)
Index: lib/libstand/dosfs.c
===================================================================
--- lib/libstand/dosfs.c
+++ lib/libstand/dosfs.c
@@ -788,7 +788,7 @@
     int	err;
 
     twiddle(1);
-    if ((err = (fd->f_dev->dv_strategy)(fd->f_devdata, F_READ, lsec, 
+    if ((err = (fd->f_dev->dv_strategy)(fd->f_devdata, F_READ, lsec, 0,
 					secbyt(nsec), buf, NULL)))
 	return(err);
     return(0);
Index: lib/libstand/ext2fs.c
===================================================================
--- lib/libstand/ext2fs.c
+++ lib/libstand/ext2fs.c
@@ -355,7 +355,7 @@
 	fp->f_fs = fs;
 	twiddle(1);
 	error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-	    EXT2_SBLOCK, EXT2_SBSIZE, (char *)fs, &buf_size);
+	    EXT2_SBLOCK, 0, EXT2_SBSIZE, (char *)fs, &buf_size);
 	if (error)
 		goto out;
 
@@ -397,7 +397,7 @@
 	fp->f_bg = malloc(len);
 	twiddle(1);
 	error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-	    EXT2_SBLOCK + EXT2_SBSIZE / DEV_BSIZE, len,
+	    EXT2_SBLOCK + EXT2_SBSIZE / DEV_BSIZE, 0, len,
 	    (char *)fp->f_bg, &buf_size);
 	if (error)
 		goto out;
@@ -509,7 +509,7 @@
 				
 				twiddle(1);
 				error = (f->f_dev->dv_strategy)(f->f_devdata,
-				    F_READ, fsb_to_db(fs, disk_block),
+				    F_READ, fsb_to_db(fs, disk_block), 0,
 				    fs->fs_bsize, buf, &buf_size);
 				if (error)
 					goto out;
@@ -570,7 +570,7 @@
 	buf = malloc(fs->fs_bsize);
 	twiddle(1);
 	error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-	    ino_to_db(fs, fp->f_bg, inumber), fs->fs_bsize, buf, &rsize);
+	    ino_to_db(fs, fp->f_bg, inumber), 0, fs->fs_bsize, buf, &rsize);
 	if (error)
 		goto out;
 	if (rsize != fs->fs_bsize) {
@@ -667,7 +667,7 @@
 					malloc(fs->fs_bsize);
 			twiddle(1);
 			error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-			    fsb_to_db(fp->f_fs, ind_block_num), fs->fs_bsize,
+			    fsb_to_db(fp->f_fs, ind_block_num), 0, fs->fs_bsize,
 			    fp->f_blk[level], &fp->f_blksize[level]);
 			if (error)
 				return (error);
@@ -725,7 +725,7 @@
 		} else {
 			twiddle(4);
 			error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-			    fsb_to_db(fs, disk_block), block_size,
+			    fsb_to_db(fs, disk_block), 0, block_size,
 			    fp->f_buf, &fp->f_buf_size);
 			if (error)
 				goto done;
Index: lib/libstand/read.c
===================================================================
--- lib/libstand/read.c
+++ lib/libstand/read.c
@@ -79,7 +79,7 @@
     if (f->f_flags & F_RAW) {
 	twiddle(4);
 	errno = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-					btodb(f->f_offset), bcount, dest, &resid);
+				btodb(f->f_offset), 0, bcount, dest, &resid);
 	if (errno)
 	    return (-1);
 	f->f_offset += resid;
Index: lib/libstand/stand.h
===================================================================
--- lib/libstand/stand.h
+++ lib/libstand/stand.h
@@ -138,8 +138,8 @@
     const char	dv_name[8];
     int		dv_type;		/* opaque type constant, arch-dependant */
     int		(*dv_init)(void);	/* early probe call */
-    int		(*dv_strategy)(void *devdata, int rw, daddr_t blk, size_t size,
-			       char *buf, size_t *rsize);
+    int		(*dv_strategy)(void *devdata, int rw, daddr_t blk,
+			size_t offset, size_t size, char *buf, size_t *rsize);
     int		(*dv_open)(struct open_file *f, ...);
     int		(*dv_close)(struct open_file *f);
     int		(*dv_ioctl)(struct open_file *f, u_long cmd, void *data);
Index: lib/libstand/ufs.c
===================================================================
--- lib/libstand/ufs.c
+++ lib/libstand/ufs.c
@@ -157,7 +157,7 @@
 	buf = malloc(fs->fs_bsize);
 	twiddle(1);
 	rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-		fsbtodb(fs, ino_to_fsba(fs, inumber)), fs->fs_bsize,
+		fsbtodb(fs, ino_to_fsba(fs, inumber)), 0, fs->fs_bsize,
 		buf, &rsize);
 	if (rc)
 		goto out;
@@ -267,7 +267,7 @@
 					malloc(fs->fs_bsize);
 			twiddle(1);
 			rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-				fsbtodb(fp->f_fs, ind_block_num),
+				fsbtodb(fp->f_fs, ind_block_num), 0,
 				fs->fs_bsize,
 				fp->f_blk[level],
 				&fp->f_blksize[level]);
@@ -348,7 +348,7 @@
 
 		twiddle(4);
 		rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-			fsbtodb(fs, disk_block),
+			fsbtodb(fs, disk_block), 0,
 			block_size, fp->f_buf, &fp->f_buf_size);
 		if (rc)
 			return (rc);
@@ -367,7 +367,7 @@
 
 	twiddle(4);
 	rc = (f->f_dev->dv_strategy)(f->f_devdata, F_WRITE,
-		fsbtodb(fs, disk_block),
+		fsbtodb(fs, disk_block), 0,
 		block_size, fp->f_buf, &fp->f_buf_size);
 	return (rc);
 }
@@ -408,7 +408,7 @@
 		} else {
 			twiddle(4);
 			rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-				fsbtodb(fs, disk_block),
+				fsbtodb(fs, disk_block), 0,
 				block_size, fp->f_buf, &fp->f_buf_size);
 			if (rc)
 				return (rc);
@@ -521,7 +521,7 @@
 	 */
 	for (i = 0; sblock_try[i] != -1; i++) {
 		rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
-		    sblock_try[i] / DEV_BSIZE, SBLOCKSIZE,
+		    sblock_try[i] / DEV_BSIZE, 0, SBLOCKSIZE,
 		    (char *)fs, &buf_size);
 		if (rc)
 			goto out;
@@ -651,7 +651,7 @@
 				
 				twiddle(1);
 				rc = (f->f_dev->dv_strategy)(f->f_devdata,
-					F_READ, fsbtodb(fs, disk_block),
+					F_READ, fsbtodb(fs, disk_block), 0,
 					fs->fs_bsize, buf, &buf_size);
 				if (rc)
 					goto out;
Index: lib/libstand/write.c
===================================================================
--- lib/libstand/write.c
+++ lib/libstand/write.c
@@ -82,7 +82,7 @@
 	if (f->f_flags & F_RAW) {
 		twiddle(4);
 		errno = (f->f_dev->dv_strategy)(f->f_devdata, F_WRITE,
-			btodb(f->f_offset), bcount, dest, &resid);
+			btodb(f->f_offset), 0, bcount, dest, &resid);
 		if (errno)
 			return (-1);
 		f->f_offset += resid;
Index: sys/boot/common/bcache.c
===================================================================
--- sys/boot/common/bcache.c
+++ sys/boot/common/bcache.c
@@ -25,10 +25,11 @@
  */
 
 #include <sys/cdefs.h>
+#include <sys/param.h>
 __FBSDID("$FreeBSD$");
 
 /*
- * Simple LRU block cache
+ * Simple hashed block cache
  */
 
 #include <sys/stdint.h>
@@ -35,7 +36,6 @@
 
 #include <stand.h>
 #include <string.h>
-#include <bitstring.h>
 
 #include "bootstrap.h"
 
@@ -42,34 +42,50 @@
 /* #define BCACHE_DEBUG */
 
 #ifdef BCACHE_DEBUG
-#define BCACHE_TIMEOUT	10
 # define DEBUG(fmt, args...)	printf("%s: " fmt "\n" , __func__ , ## args)
 #else
-#define BCACHE_TIMEOUT	2
 # define DEBUG(fmt, args...)
 #endif
 
-
 struct bcachectl
 {
     daddr_t	bc_blkno;
-    time_t	bc_stamp;
     int		bc_count;
 };
 
-static struct bcachectl	*bcache_ctl;
-static caddr_t		bcache_data;
-static bitstr_t		*bcache_miss;
-static u_int		bcache_nblks;
-static u_int		bcache_blksize;
-static u_int		bcache_hits, bcache_misses, bcache_ops, bcache_bypasses;
-static u_int		bcache_flushes;
-static u_int		bcache_bcount;
+/*
+ * bcache per device node. cache is allocated on device first open and freed
+ * on last close, to save memory. The issue there is the size; biosdisk
+ * supports up to 31 (0x1f) devices. Classic setup would use single disk
+ * to boot from, but this has changed with zfs.
+ */
+struct bcache {
+    struct bcachectl *bcache_ctl;
+    caddr_t bcache_data;
+    u_int bcache_nblks;
+};
 
-static void	bcache_invalidate(daddr_t blkno);
-static void	bcache_insert(caddr_t buf, daddr_t blkno);
-static int	bcache_lookup(caddr_t buf, daddr_t blkno);
+static u_int bcache_total_nblks;	/* set by bcache_init */
+static u_int bcache_blksize;		/* set by bcache_init */
+static u_int bcache_numdev;		/* set by bcache_add_dev */
+/* statistics */
+static u_int bcache_units;	/* number of devices with cache */
+static u_int bcache_unit_nblks;	/* nblocks per unit */
+static u_int bcache_hits;
+static u_int bcache_misses;
+static u_int bcache_ops;
+static u_int bcache_bypasses;
+static u_int bcache_bcount;
+static u_int bcache_rablks;
 
+#define	BHASH(bc, blkno)	(((u_int)(blkno)) & ((bc)->bcache_nblks - 1))
+#define	BCACHE_LOOKUP(bc, blkno)	\
+	((bc)->bcache_ctl[BHASH((bc), (blkno))].bc_blkno != (blkno))
+#define	BCACHE_READAHEAD	256
+
+static void	bcache_invalidate(struct bcache *bc, daddr_t blkno);
+static void	bcache_insert(struct bcache *bc, daddr_t blkno);
+
 /*
  * Initialise the cache for (nblks) of (bsize).
  */
@@ -76,59 +92,104 @@
 int
 bcache_init(u_int nblks, size_t bsize)
 {
-    /* discard any old contents */
-    if (bcache_data != NULL) {
-	free(bcache_data);
-	bcache_data = NULL;
-	free(bcache_ctl);
-    }
-
-    /* Allocate control structures */
-    bcache_nblks = nblks;
+    /* set up control data */
+    bcache_total_nblks = nblks;
     bcache_blksize = bsize;
-    bcache_data = malloc(bcache_nblks * bcache_blksize);
-    bcache_ctl = (struct bcachectl *)malloc(bcache_nblks * sizeof(struct bcachectl));
-    bcache_miss = bit_alloc((bcache_nblks + 1) / 2);
-    if ((bcache_data == NULL) || (bcache_ctl == NULL) || (bcache_miss == NULL)) {
-	if (bcache_miss)
-	    free(bcache_miss);
-	if (bcache_ctl)
-	    free(bcache_ctl);
-	if (bcache_data)
-	    free(bcache_data);
-	bcache_data = NULL;
-	return(ENOMEM);
-    }
 
     return(0);
 }
 
 /*
- * Flush the cache
+ * add number of devices to bcache. we have to divide cache space
+ * between the devices, so bcache_add_dev() can be used to set up the
+ * number. The issue is, we need to get the number before actual allocations.
+ * bcache_add_dev() is supposed to be called from device init() call, so the
+ * assumption is, devsw dv_init is called for plain devices first, and
+ * for zfs, last.
  */
 void
-bcache_flush(void)
+bcache_add_dev(int devices)
 {
-    u_int	i;
+    bcache_numdev += devices;
+}
 
-    bcache_flushes++;
+void *
+bcache_allocate(void)
+{
+    int i, n;
+    struct bcache *bc = malloc(sizeof (struct bcache));
+    int disks = bcache_numdev;
 
+    if (disks == 0)
+	disks = 1;	/* safe guard */
+    if (bc == NULL) {
+	errno = ENOMEM;
+	return (bc);
+    }
+    i = 0;
+    n = disks;
+    while (n != 1) {
+	n >>= 1;
+	i++;
+    }
+    if (disks > (1 << i))
+	i++;
+    bc->bcache_nblks = bcache_total_nblks >> i;
+    bcache_unit_nblks = bc->bcache_nblks;
+    bc->bcache_data = malloc(bc->bcache_nblks * bcache_blksize);
+    if (bc->bcache_data == NULL) {
+	/* dont error out yet. fall back to 32 blocks and try again */
+	bc->bcache_nblks = 32;
+	bc->bcache_data = malloc(bc->bcache_nblks * bcache_blksize);
+    }
+
+    bc->bcache_ctl = malloc(bc->bcache_nblks * sizeof(struct bcachectl));
+
+    if ((bc->bcache_data == NULL) || (bc->bcache_ctl == NULL)) {
+	if (bc->bcache_ctl)
+	    free(bc->bcache_ctl);
+	if (bc->bcache_data)
+	    free(bc->bcache_data);
+	free(bc);
+	errno = ENOMEM;
+	return(NULL);
+    }
+
     /* Flush the cache */
-    for (i = 0; i < bcache_nblks; i++) {
-	bcache_ctl[i].bc_count = -1;
-	bcache_ctl[i].bc_blkno = -1;
+    for (i = 0; i < bc->bcache_nblks; i++) {
+	bc->bcache_ctl[i].bc_count = -1;
+	bc->bcache_ctl[i].bc_blkno = -1;
     }
+    bcache_units++;
+    return (bc);
 }
 
+void
+bcache_free(void *cache)
+{
+    struct bcache *bc = cache;
+
+    if (bc == NULL)
+	return;
+
+    if (bc->bcache_ctl)
+	    free(bc->bcache_ctl);
+    if (bc->bcache_data)
+	    free(bc->bcache_data);
+    free(bc);
+    bcache_units--;
+}
+
 /*
  * Handle a write request; write directly to the disk, and populate the
  * cache with the new values.
  */
 static int
-write_strategy(void *devdata, int unit, int rw, daddr_t blk, size_t size,
-		char *buf, size_t *rsize)
+write_strategy(void *devdata, int rw, daddr_t blk, size_t offset,
+    size_t size, char *buf, size_t *rsize)
 {
     struct bcache_devdata	*dd = (struct bcache_devdata *)devdata;
+    struct bcache		*bc = dd->dv_cache;
     daddr_t			i, nblk;
     int				err;
 
@@ -136,12 +197,13 @@
 
     /* Invalidate the blocks being written */
     for (i = 0; i < nblk; i++) {
-	bcache_invalidate(blk + i);
+	bcache_invalidate(bc, blk + i);
     }
 
     /* Write the blocks */
-    err = dd->dv_strategy(dd->dv_devdata, rw, blk, size, buf, rsize);
+    err = dd->dv_strategy(dd->dv_devdata, rw, blk, offset, size, buf, rsize);
 
+#if 0
     /* Populate the block cache with the new data */
     if (err == 0) {
     	for (i = 0; i < nblk; i++) {
@@ -148,6 +210,7 @@
 	    bcache_insert(buf + (i * bcache_blksize),blk + i);
     	}
     }
+#endif
 
     return err;
 }
@@ -158,61 +221,72 @@
  * device I/O and then use the I/O results to populate the cache. 
  */
 static int
-read_strategy(void *devdata, int unit, int rw, daddr_t blk, size_t size,
-		char *buf, size_t *rsize)
+read_strategy(void *devdata, int rw, daddr_t blk, size_t offset,
+    size_t size, char *buf, size_t *rsize)
 {
     struct bcache_devdata	*dd = (struct bcache_devdata *)devdata;
-    int				p_size, result;
-    daddr_t			p_blk, i, j, nblk;
+    struct bcache		*bc = dd->dv_cache;
+    int				p_size, r_size, result, complete, ra;
+    int				i, j, nblk;
+    daddr_t			p_blk;
     caddr_t			p_buf;
 
+    if (bc == NULL) {
+	errno = ENODEV;
+	return (-1);
+    }
+
     nblk = size / bcache_blksize;
+    if ((nblk == 0 && size != 0) || offset != 0)
+	nblk++;
     result = 0;
+    complete = 1;
 
-    /* Satisfy any cache hits up front */
+    /* Satisfy any cache hits up front, break on first miss */
     for (i = 0; i < nblk; i++) {
-	if (bcache_lookup(buf + (bcache_blksize * i), blk + i)) {
-	    bit_set(bcache_miss, i);	/* cache miss */
-	    bcache_misses++;
+	if (BCACHE_LOOKUP(bc, blk + i)) {
+	    bcache_misses += (nblk - i);
+	    complete = 0;
+	    break;
 	} else {
-	    bit_clear(bcache_miss, i);	/* cache hit */
 	    bcache_hits++;
 	}
     }
 
-    /* Go back and fill in any misses  XXX optimise */
-    p_blk = -1;
-    p_buf = NULL;
-    p_size = 0;
-    for (i = 0; i < nblk; i++) {
-	if (bit_test(bcache_miss, i)) {
-	    /* miss, add to pending transfer */
-	    if (p_blk == -1) {
-		p_blk = blk + i;
-		p_buf = buf + (bcache_blksize * i);
-		p_size = 1;
-	    } else {
-		p_size++;
-	    }
-	} else if (p_blk != -1) {
-	    /* hit, complete pending transfer */
-	    result = dd->dv_strategy(dd->dv_devdata, rw, p_blk, p_size * bcache_blksize, p_buf, NULL);
-	    if (result != 0)
-		goto done;
-	    for (j = 0; j < p_size; j++)
-		bcache_insert(p_buf + (j * bcache_blksize), p_blk + j);
-	    p_blk = -1;
-	}
+   if (complete) {	/* whole set was in cache, return it */
+	bcopy(bc->bcache_data + (bcache_blksize * BHASH(bc, blk)) + offset,
+	    buf, size);
+	goto done;
+   }
+
+    /*
+     * Fill in any misses. From check we have i pointing to first missing
+     * block, read in all remaining blocks + readahead.
+     * We have space at least for nblk - i before bcache wraps.
+     */
+    p_blk = blk + i;
+    p_buf = bc->bcache_data + (bcache_blksize * BHASH(bc, p_blk));
+    r_size = bc->bcache_nblks - BHASH(bc, p_blk); /* remaining blocks */
+
+    p_size = MIN(r_size, nblk - i);	/* read at least those blocks */
+
+    ra = bc->bcache_nblks - (unsigned)BHASH(bc, p_blk + p_size);
+    if (ra != bc->bcache_nblks) { /* do we have RA space? */
+	ra = MIN(BCACHE_READAHEAD, ra);
+	p_size += ra;
     }
-    if (p_blk != -1) {
-	/* pending transfer left */
-	result = dd->dv_strategy(dd->dv_devdata, rw, p_blk, p_size * bcache_blksize, p_buf, NULL);
-	if (result != 0)
-	    goto done;
-	for (j = 0; j < p_size; j++)
-	    bcache_insert(p_buf + (j * bcache_blksize), p_blk + j);
-    }
-    
+
+    result = dd->dv_strategy(dd->dv_devdata, rw, p_blk, 0,
+	p_size * bcache_blksize, p_buf, NULL);
+    if (result != 0)
+	goto done;
+    for (j = 0; j < p_size; j++)
+	bcache_insert(bc, p_blk + j);
+    bcache_rablks += p_size;
+
+    bcopy(bc->bcache_data + (bcache_blksize * BHASH(bc, blk)) + offset, buf,
+	size);
+
  done:
     if ((result == 0) && (rsize != NULL))
 	*rsize = size;
@@ -220,35 +294,76 @@
 }
 
 /* 
- * Requests larger than 1/2 the cache size will be bypassed and go
+ * Requests larger than 1/2 cache size will be bypassed and go
  * directly to the disk.  XXX tune this.
  */
 int
-bcache_strategy(void *devdata, int unit, int rw, daddr_t blk, size_t size,
-		char *buf, size_t *rsize)
+bcache_strategy(void *devdata, int rw, daddr_t blk, size_t offset,
+    size_t size, char *buf, size_t *rsize)
 {
-    static int			bcache_unit = -1;
     struct bcache_devdata	*dd = (struct bcache_devdata *)devdata;
+    struct bcache		*bc = dd->dv_cache;
+    u_int bcache_nblks = 0;
+    int nblk, cblk, ret;
+    size_t csize, isize, total;
 
     bcache_ops++;
 
-    if(bcache_unit != unit) {
-	bcache_flush();
-	bcache_unit = unit;
-    }
+    if (bc != NULL)
+	bcache_nblks = bc->bcache_nblks;
 
     /* bypass large requests, or when the cache is inactive */
-    if ((bcache_data == NULL) || ((size * 2 / bcache_blksize) > bcache_nblks)) {
+    if (bc == NULL ||
+	(offset == 0 && ((size * 2 / bcache_blksize) > bcache_nblks))) {
 	DEBUG("bypass %d from %d", size / bcache_blksize, blk);
 	bcache_bypasses++;
-	return(dd->dv_strategy(dd->dv_devdata, rw, blk, size, buf, rsize));
+	return (dd->dv_strategy(dd->dv_devdata, rw, blk, offset, size, buf,
+	    rsize));
     }
 
+    /* normalize offset */
+    while (offset >= bcache_blksize) {
+	blk++;
+	offset -= bcache_blksize;
+    }
+
     switch (rw) {
     case F_READ:
-	return read_strategy(devdata, unit, rw, blk, size, buf, rsize);
+	nblk = size / bcache_blksize;
+	if (offset || (size != 0 && nblk == 0))
+	    nblk++;	/* read at least one block */
+
+	ret = 0;
+	total = 0;
+	while(size) {
+	    cblk = bcache_nblks - BHASH(bc, blk); /* # of blocks left */
+	    cblk = MIN(cblk, nblk);
+
+	    if (size <= bcache_blksize)
+		csize = size;
+	    else {
+		csize = cblk * bcache_blksize;
+		if (offset)
+		    csize -= (bcache_blksize - offset);
+	    }
+
+	    ret = read_strategy(devdata, rw, blk, offset,
+		csize, buf+total, &isize);
+	    if (ret != 0)
+		return (ret);
+	    blk += (offset+isize) / bcache_blksize;
+	    offset = 0;
+	    total += isize;
+	    size -= isize;
+	    nblk = size / bcache_blksize;
+	}
+
+	if (rsize)
+	    *rsize = total;
+
+	return (ret);
     case F_WRITE:
-	return write_strategy(devdata, unit, rw, blk, size, buf, rsize);
+	return write_strategy(devdata, rw, blk, offset, size, buf, rsize);
     }
     return -1;
 }
@@ -255,95 +370,54 @@
 
 
 /*
- * Insert a block into the cache.  Retire the oldest block to do so, if required.
- *
- * XXX the LRU algorithm will fail after 2^31 blocks have been transferred.
+ * Insert a block into the cache.
  */
 static void
-bcache_insert(caddr_t buf, daddr_t blkno) 
+bcache_insert(struct bcache *bc, daddr_t blkno)
 {
-    time_t	now;
-    int		cand, ocount;
-    u_int	i;
+    u_int	cand;
     
-    time(&now);
-    cand = 0;				/* assume the first block */
-    ocount = bcache_ctl[0].bc_count;
+    cand = BHASH(bc, blkno);
 
-    /* find the oldest block */
-    for (i = 1; i < bcache_nblks; i++) {
-	if (bcache_ctl[i].bc_blkno == blkno) {
-	    /* reuse old entry */
-	    cand = i;
-	    break;
-	}
-	if (bcache_ctl[i].bc_count < ocount) {
-	    ocount = bcache_ctl[i].bc_count;
-	    cand = i;
-	}
-    }
-    
-    DEBUG("insert blk %d -> %d @ %d # %d", blkno, cand, now, bcache_bcount);
-    bcopy(buf, bcache_data + (bcache_blksize * cand), bcache_blksize);
-    bcache_ctl[cand].bc_blkno = blkno;
-    bcache_ctl[cand].bc_stamp = now;
-    bcache_ctl[cand].bc_count = bcache_bcount++;
+    DEBUG("insert blk %llu -> %u # %d", blkno, cand, bcache_bcount);
+    bc->bcache_ctl[cand].bc_blkno = blkno;
+    bc->bcache_ctl[cand].bc_count = bcache_bcount++;
 }
 
 /*
- * Look for a block in the cache.  Blocks more than BCACHE_TIMEOUT seconds old
- * may be stale (removable media) and thus are discarded.  Copy the block out 
- * if successful and return zero, or return nonzero on failure.
- */
-static int
-bcache_lookup(caddr_t buf, daddr_t blkno)
-{
-    time_t	now;
-    u_int	i;
-    
-    time(&now);
-
-    for (i = 0; i < bcache_nblks; i++)
-	/* cache hit? */
-	if ((bcache_ctl[i].bc_blkno == blkno) && ((bcache_ctl[i].bc_stamp + BCACHE_TIMEOUT) >= now)) {
-	    bcopy(bcache_data + (bcache_blksize * i), buf, bcache_blksize);
-	    DEBUG("hit blk %d <- %d (now %d then %d)", blkno, i, now, bcache_ctl[i].bc_stamp);
-	    return(0);
-	}
-    return(ENOENT);
-}
-
-/*
  * Invalidate a block from the cache.
  */
 static void
-bcache_invalidate(daddr_t blkno)
+bcache_invalidate(struct bcache *bc, daddr_t blkno)
 {
     u_int	i;
     
-    for (i = 0; i < bcache_nblks; i++) {
-	if (bcache_ctl[i].bc_blkno == blkno) {
-	    bcache_ctl[i].bc_count = -1;
-	    bcache_ctl[i].bc_blkno = -1;
-	    DEBUG("invalidate blk %d", blkno);
-	    break;
-	}
+    i = BHASH(bc, blkno);
+    if (bc->bcache_ctl[i].bc_blkno == blkno) {
+	bc->bcache_ctl[i].bc_count = -1;
+	bc->bcache_ctl[i].bc_blkno = -1;
+	DEBUG("invalidate blk %llu", blkno);
     }
 }
 
+#ifndef BOOT2
 COMMAND_SET(bcachestat, "bcachestat", "get disk block cache stats", command_bcache);
 
 static int
 command_bcache(int argc, char *argv[])
 {
-    u_int	i;
-    
-    for (i = 0; i < bcache_nblks; i++) {
-	printf("%08jx %04x %04x|", (uintmax_t)bcache_ctl[i].bc_blkno, (unsigned int)bcache_ctl[i].bc_stamp & 0xffff, bcache_ctl[i].bc_count & 0xffff);
-	if (((i + 1) % 4) == 0)
-	    printf("\n");
+    if (argc != 1) {
+	command_errmsg = "wrong number of arguments";
+	return(CMD_ERROR);
     }
-    printf("\n%d ops  %d bypasses  %d hits  %d misses  %d flushes\n", bcache_ops, bcache_bypasses, bcache_hits, bcache_misses, bcache_flushes);
+
+    printf("\ncache blocks: %d\n", bcache_total_nblks);
+    printf("cache blocksz: %d\n", bcache_blksize);
+    printf("cache readahead: %d\n", bcache_rablks);
+    printf("unit cache blocks: %d\n", bcache_unit_nblks);
+    printf("cached units: %d\n", bcache_units);
+    printf("%d ops  %d bypasses  %d hits  %d misses\n", bcache_ops,
+	bcache_bypasses, bcache_hits, bcache_misses);
     return(CMD_OK);
 }
-
+#endif
Index: sys/boot/common/bootstrap.h
===================================================================
--- sys/boot/common/bootstrap.h
+++ sys/boot/common/bootstrap.h
@@ -88,8 +88,10 @@
 
 /* bcache.c */
 int	bcache_init(u_int nblks, size_t bsize);
-void	bcache_flush(void);
-int	bcache_strategy(void *devdata, int unit, int rw, daddr_t blk,
+void	bcache_add_dev(int);
+void	*bcache_allocate(void);
+void	bcache_free(void *);
+int	bcache_strategy(void *devdata, int rw, daddr_t blk, size_t offset,
 			size_t size, char *buf, size_t *rsize);
 
 /*
@@ -97,8 +99,10 @@
  */
 struct bcache_devdata
 {
-    int         (*dv_strategy)(void *devdata, int rw, daddr_t blk, size_t size, char *buf, size_t *rsize);
+    int         (*dv_strategy)(void *devdata, int rw, daddr_t blk,
+			size_t offset, size_t size, char *buf, size_t *rsize);
     void	*dv_devdata;
+    void	*dv_cache;
 };
 
 /*
Index: sys/boot/common/disk.c
===================================================================
--- sys/boot/common/disk.c
+++ sys/boot/common/disk.c
@@ -178,7 +178,7 @@
 
 	dev = (struct disk_devdesc *)d;
 	od = (struct open_disk *)dev->d_opendata;
-	return (dev->d_dev->dv_strategy(dev, F_READ, offset,
+	return (dev->d_dev->dv_strategy(dev, F_READ, offset, 0,
 	    blocks * od->sectorsize, (char *)buf, NULL));
 }
 
@@ -239,7 +239,7 @@
 	int ret;
 
 	od = (struct open_disk *)dev->d_opendata;
-	ret = dev->d_dev->dv_strategy(dev, F_READ, dev->d_offset + offset,
+	ret = dev->d_dev->dv_strategy(dev, F_READ, dev->d_offset + offset, 0,
 	    blocks * od->sectorsize, buf, NULL);
 
 	return (ret);
@@ -252,7 +252,7 @@
 	int ret;
 
 	od = (struct open_disk *)dev->d_opendata;
-	ret = dev->d_dev->dv_strategy(dev, F_WRITE, dev->d_offset + offset,
+	ret = dev->d_dev->dv_strategy(dev, F_WRITE, dev->d_offset + offset, 0,
 	    blocks * od->sectorsize, buf, NULL);
 
 	return (ret);
Index: sys/boot/common/md.c
===================================================================
--- sys/boot/common/md.c
+++ sys/boot/common/md.c
@@ -60,7 +60,7 @@
 
 /* devsw I/F */
 static int md_init(void);
-static int md_strategy(void *, int, daddr_t, size_t, char *, size_t *);
+static int md_strategy(void *, int, daddr_t, size_t, size_t, char *, size_t *);
 static int md_open(struct open_file *, ...);
 static int md_close(struct open_file *);
 static void md_print(int);
@@ -84,8 +84,8 @@
 }
 
 static int
-md_strategy(void *devdata, int rw, daddr_t blk, size_t size, char *buf,
-    size_t *rsize)
+md_strategy(void *devdata, int rw, daddr_t blk, size_t offset, size_t size,
+    char *buf, size_t *rsize)
 {
 	struct devdesc *dev = (struct devdesc *)devdata;
 	size_t ofs;
Index: sys/boot/efi/libefi/efipart.c
===================================================================
--- sys/boot/efi/libefi/efipart.c
+++ sys/boot/efi/libefi/efipart.c
@@ -42,7 +42,8 @@
 static EFI_GUID devpath_guid = DEVICE_PATH_PROTOCOL;
 
 static int efipart_init(void);
-static int efipart_strategy(void *, int, daddr_t, size_t, char *, size_t *);
+static int efipart_strategy(void *, int, daddr_t, size_t, size_t, char *,
+    size_t *);
 static int efipart_open(struct open_file *, ...);
 static int efipart_close(struct open_file *);
 static void efipart_print(int);
@@ -256,8 +257,8 @@
 }
 
 static int 
-efipart_strategy(void *devdata, int rw, daddr_t blk, size_t size, char *buf,
-    size_t *rsize)
+efipart_strategy(void *devdata, int rw, daddr_t blk, size_t offset,
+    size_t size, char *buf, size_t *rsize)
 {
 	struct devdesc *dev = (struct devdesc *)devdata;
 	EFI_BLOCK_IO *blkio;
Index: sys/boot/i386/libi386/bioscd.c
===================================================================
--- sys/boot/i386/libi386/bioscd.c
+++ sys/boot/i386/libi386/bioscd.c
@@ -85,13 +85,19 @@
 static struct bcinfo {
 	int	bc_unit;		/* BIOS unit number */
 	struct specification_packet bc_sp;
+	int	bc_open;		/* reference counter */
+	void	*bc_bcache;		/* buffer cache data */
 } bcinfo [MAXBCDEV];
 static int nbcinfo = 0;
 
+#define	BC(dev)	(bcinfo[(dev)->d_unit])
+
 static int	bc_read(int unit, daddr_t dblk, int blks, caddr_t dest);
 static int	bc_init(void);
 static int	bc_strategy(void *devdata, int flag, daddr_t dblk,
-		    size_t size, char *buf, size_t *rsize);
+    size_t offset, size_t size, char *buf, size_t *rsize);
+static int	bc_realstrategy(void *devdata, int flag, daddr_t dblk,
+    size_t offset, size_t size, char *buf, size_t *rsize);
 static int	bc_open(struct open_file *f, ...);
 static int	bc_close(struct open_file *f);
 static void	bc_print(int verbose);
@@ -164,6 +170,7 @@
 
 	printf("BIOS CD is cd%d\n", nbcinfo);
 	nbcinfo++;
+	bcache_add_dev(nbcinfo);	/* register cd device in bcache */
 	return(0);
 }
 
@@ -200,6 +207,9 @@
 		return(ENXIO);
 	}
 
+	BC(dev).bc_open++;
+	if (BC(dev).bc_bcache == NULL)
+	    BC(dev).bc_bcache = bcache_allocate();
 	return(0);
 }
  
@@ -206,13 +216,35 @@
 static int 
 bc_close(struct open_file *f)
 {
+	struct i386_devdesc *dev;
 
+	dev = (struct i386_devdesc *)f->f_devdata;
+	BC(dev).bc_open--;
+	if (BC(dev).bc_open == 0) {
+	    bcache_free(BC(dev).bc_bcache);
+	    BC(dev).bc_bcache = NULL;
+	}
 	return(0);
 }
 
+static int
+bc_strategy(void *devdata, int rw, daddr_t dblk, size_t offset, size_t size,
+    char *buf, size_t *rsize)
+{
+	struct bcache_devdata bcd;
+	struct i386_devdesc *dev;
+
+	dev = (struct i386_devdesc *)devdata;
+	bcd.dv_strategy = bc_realstrategy;
+	bcd.dv_devdata = devdata;
+	bcd.dv_cache = BC(dev).bc_bcache;
+
+	return (bcache_strategy(&bcd, rw, dblk, offset, size, buf, rsize));
+}
+
 static int 
-bc_strategy(void *devdata, int rw, daddr_t dblk, size_t size, char *buf,
-    size_t *rsize)
+bc_realstrategy(void *devdata, int rw, daddr_t dblk, size_t offset, size_t size,
+    char *buf, size_t *rsize)
 {
 	struct i386_devdesc *dev;
 	int unit;
Index: sys/boot/i386/libi386/biosdisk.c
===================================================================
--- sys/boot/i386/libi386/biosdisk.c
+++ sys/boot/i386/libi386/biosdisk.c
@@ -86,6 +86,8 @@
 	int		bd_type;	/* BIOS 'drive type' (floppy only) */
 	uint16_t	bd_sectorsize;	/* Sector size */
 	uint64_t	bd_sectors;	/* Disk size */
+	int		bd_open;	/* reference counter */
+	void		*bd_bcache;	/* buffer cache data */
 } bdinfo [MAXBDDEV];
 static int nbdinfo = 0;
 
@@ -98,10 +100,10 @@
 static int bd_int13probe(struct bdinfo *bd);
 
 static int bd_init(void);
-static int bd_strategy(void *devdata, int flag, daddr_t dblk, size_t size,
-    char *buf, size_t *rsize);
-static int bd_realstrategy(void *devdata, int flag, daddr_t dblk,
+static int bd_strategy(void *devdata, int flag, daddr_t dblk, size_t offset,
     size_t size, char *buf, size_t *rsize);
+static int bd_realstrategy(void *devdata, int flag, daddr_t dblk, size_t offset,
+    size_t size, char *buf, size_t *rsize);
 static int bd_open(struct open_file *f, ...);
 static int bd_close(struct open_file *f);
 static int bd_ioctl(struct open_file *f, u_long cmd, void *data);
@@ -166,6 +168,8 @@
 			    (nfd >= *(unsigned char *)PTOV(BIOS_NUMDRIVES)))
 				break;
 #endif
+			bdinfo[nbdinfo].bd_open = 0;
+			bdinfo[nbdinfo].bd_bcache = NULL;
 			bdinfo[nbdinfo].bd_unit = unit;
 			bdinfo[nbdinfo].bd_flags = unit < 0x80 ? BD_FLOPPY: 0;
 			if (!bd_int13probe(&bdinfo[nbdinfo]))
@@ -179,6 +183,7 @@
 				nfd++;
 		}
 	}
+	bcache_add_dev(nbdinfo);
 	return(0);
 }
 
@@ -308,7 +313,9 @@
 
 	if (dev->d_unit < 0 || dev->d_unit >= nbdinfo)
 		return (EIO);
-
+	BD(dev).bd_open++;
+	if (BD(dev).bd_bcache == NULL)
+	    BD(dev).bd_bcache = bcache_allocate();
 	return (disk_open(dev, BD(dev).bd_sectors * BD(dev).bd_sectorsize,
 	    BD(dev).bd_sectorsize, (BD(dev).bd_flags & BD_FLOPPY) ?
 	    DISK_F_NOCACHE: 0));
@@ -320,6 +327,11 @@
 	struct disk_devdesc *dev;
 
 	dev = (struct disk_devdesc *)f->f_devdata;
+	BD(dev).bd_open--;
+	if (BD(dev).bd_open == 0) {
+	    bcache_free(BD(dev).bd_bcache);
+	    BD(dev).bd_bcache = NULL;
+	}
 	return (disk_close(dev));
 }
 
@@ -343,8 +355,8 @@
 }
 
 static int
-bd_strategy(void *devdata, int rw, daddr_t dblk, size_t size, char *buf,
-    size_t *rsize)
+bd_strategy(void *devdata, int rw, daddr_t dblk, size_t offset, size_t size,
+    char *buf, size_t *rsize)
 {
 	struct bcache_devdata bcd;
 	struct disk_devdesc *dev;
@@ -352,13 +364,14 @@
 	dev = (struct disk_devdesc *)devdata;
 	bcd.dv_strategy = bd_realstrategy;
 	bcd.dv_devdata = devdata;
-	return (bcache_strategy(&bcd, BD(dev).bd_unit, rw, dblk + dev->d_offset,
-	    size, buf, rsize));
+	bcd.dv_cache = BD(dev).bd_bcache;
+	return (bcache_strategy(&bcd, rw, dblk + dev->d_offset, offset, size,
+	    buf, rsize));
 }
 
 static int
-bd_realstrategy(void *devdata, int rw, daddr_t dblk, size_t size, char *buf,
-    size_t *rsize)
+bd_realstrategy(void *devdata, int rw, daddr_t dblk, size_t offset, size_t size,
+    char *buf, size_t *rsize)
 {
     struct disk_devdesc *dev = (struct disk_devdesc *)devdata;
     int			blks;
Index: sys/boot/i386/libi386/biosmem.c
===================================================================
--- sys/boot/i386/libi386/biosmem.c
+++ sys/boot/i386/libi386/biosmem.c
@@ -56,7 +56,7 @@
 /*
  * The minimum amount of memory to reserve in bios_extmem for the heap.
  */
-#define	HEAP_MIN	(3 * 1024 * 1024)
+#define	HEAP_MIN	(64 * 1024 * 1024)
 
 /*
  * Products in this list need quirks to detect
Index: sys/boot/i386/libi386/pxe.c
===================================================================
--- sys/boot/i386/libi386/pxe.c
+++ sys/boot/i386/libi386/pxe.c
@@ -72,7 +72,7 @@
 
 static int	pxe_init(void);
 static int	pxe_strategy(void *devdata, int flag, daddr_t dblk,
-			     size_t size, char *buf, size_t *rsize);
+			     size_t offset, size_t size, char *buf, size_t *rsize);
 static int	pxe_open(struct open_file *f, ...);
 static int	pxe_close(struct open_file *f);
 static void	pxe_print(int verbose);
@@ -247,7 +247,7 @@
 
 
 static int
-pxe_strategy(void *devdata, int flag, daddr_t dblk, size_t size,
+pxe_strategy(void *devdata, int flag, daddr_t dblk, size_t offset, size_t size,
 		char *buf, size_t *rsize)
 {
 	return (EIO);
Index: sys/boot/i386/loader/main.c
===================================================================
--- sys/boot/i386/loader/main.c
+++ sys/boot/i386/loader/main.c
@@ -137,9 +137,9 @@
     cons_probe();
 
     /*
-     * Initialise the block cache
+     * Initialise the block cache. Set the upper limit.
      */
-    bcache_init(32, 512);	/* 16k cache XXX tune this */
+    bcache_init(32768, 512);
 
     /*
      * Special handling for PXE and CD booting.
Index: sys/boot/zfs/zfs.c
===================================================================
--- sys/boot/zfs/zfs.c
+++ sys/boot/zfs/zfs.c
@@ -564,7 +564,7 @@
 }
 
 static int
-zfs_dev_strategy(void *devdata, int rw, daddr_t dblk, size_t size, char *buf, size_t *rsize)
+zfs_dev_strategy(void *devdata, int rw, daddr_t dblk, size_t offset, size_t size, char *buf, size_t *rsize)
 {
 
 	return (ENOSYS);