Merge branch 'for-linus' of git://neil.brown.name/md

* 'for-linus' of git://neil.brown.name/md: (53 commits)
  md/raid5 revise rules for when to update metadata during reshape
  md/raid5: minor code cleanups in make_request.
  md: remove CONFIG_MD_RAID_RESHAPE config option.
  md/raid5: be more careful about write ordering when reshaping.
  md: don't display meaningless values in sysfs files resync_start and sync_speed
  md/raid5: allow layout and chunksize to be changed on active array.
  md/raid5: reshape using largest of old and new chunk size
  md/raid5: prepare for allowing reshape to change layout
  md/raid5: prepare for allowing reshape to change chunksize.
  md/raid5: clearly differentiate 'before' and 'after' stripes during reshape.
  Documentation/md.txt update
  md: allow number of drives in raid5 to be reduced
  md/raid5: change reshape-progress measurement to cope with reshaping backwards.
  md: add explicit method to signal the end of a reshape.
  md/raid5: enhance raid5_size to work correctly with negative delta_disks
  md/raid5: drop qd_idx from r6_state
  md/raid6: move raid6 data processing to raid6_pq.ko
  md: raid5 run(): Fix max_degraded for raid level 4.
  md: 'array_size' sysfs attribute
  md: centralize ->array_sectors modifications
  ...

31 files changed, 3324 insertions, 837 deletions

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 2281b50..36e0675 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -121,6 +121,7 @@ config MD_RAID10
 config MD_RAID456
 	tristate "RAID-4/RAID-5/RAID-6 mode"
 	depends on BLK_DEV_MD
+	select MD_RAID6_PQ
 	select ASYNC_MEMCPY
 	select ASYNC_XOR
 	---help---
@@ -151,34 +152,8 @@ config MD_RAID456
 
 	  If unsure, say Y.
 
-config MD_RAID5_RESHAPE
-	bool "Support adding drives to a raid-5 array"
-	depends on MD_RAID456
-	default y
-	---help---
-	  A RAID-5 set can be expanded by adding extra drives. This
-	  requires "restriping" the array which means (almost) every
-	  block must be written to a different place.
-
-          This option allows such restriping to be done while the array
-	  is online.
-
-	  You will need mdadm version 2.4.1 or later to use this
-	  feature safely.  During the early stage of reshape there is
-	  a critical section where live data is being over-written.  A
-	  crash during this time needs extra care for recovery.  The
-	  newer mdadm takes a copy of the data in the critical section
-	  and will restore it, if necessary, after a crash.
-
-	  The mdadm usage is e.g.
-	       mdadm --grow /dev/md1 --raid-disks=6
-	  to grow '/dev/md1' to having 6 disks.
-
-	  Note: The array can only be expanded, not contracted.
-	  There should be enough spares already present to make the new
-	  array workable.
-
-	  If unsure, say Y.
+config MD_RAID6_PQ
+	tristate
 
 config MD_MULTIPATH
 	tristate "Multipath I/O support"
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 72880b7..45cc595 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -2,20 +2,21 @@
 # Makefile for the kernel software RAID and LVM drivers.
 #
 
-dm-mod-objs	:= dm.o dm-table.o dm-target.o dm-linear.o dm-stripe.o \
+dm-mod-y	+= dm.o dm-table.o dm-target.o dm-linear.o dm-stripe.o \
 		   dm-ioctl.o dm-io.o dm-kcopyd.o dm-sysfs.o
-dm-multipath-objs := dm-path-selector.o dm-mpath.o
-dm-snapshot-objs := dm-snap.o dm-exception-store.o dm-snap-transient.o \
+dm-multipath-y	+= dm-path-selector.o dm-mpath.o
+dm-snapshot-y	+= dm-snap.o dm-exception-store.o dm-snap-transient.o \
 		    dm-snap-persistent.o
-dm-mirror-objs	:= dm-raid1.o
-md-mod-objs     := md.o bitmap.o
-raid456-objs	:= raid5.o raid6algos.o raid6recov.o raid6tables.o \
+dm-mirror-y	+= dm-raid1.o
+md-mod-y	+= md.o bitmap.o
+raid456-y	+= raid5.o
+raid6_pq-y	+= raid6algos.o raid6recov.o raid6tables.o \
 		   raid6int1.o raid6int2.o raid6int4.o \
 		   raid6int8.o raid6int16.o raid6int32.o \
 		   raid6altivec1.o raid6altivec2.o raid6altivec4.o \
 		   raid6altivec8.o \
 		   raid6mmx.o raid6sse1.o raid6sse2.o
-hostprogs-y	:= mktables
+hostprogs-y	+= mktables
 
 # Note: link order is important.  All raid personalities
 # and must come before md.o, as they each initialise 
@@ -26,6 +27,7 @@ obj-$(CONFIG_MD_LINEAR)		+= linear.o
 obj-$(CONFIG_MD_RAID0)		+= raid0.o
 obj-$(CONFIG_MD_RAID1)		+= raid1.o
 obj-$(CONFIG_MD_RAID10)		+= raid10.o
+obj-$(CONFIG_MD_RAID6_PQ)	+= raid6_pq.o
 obj-$(CONFIG_MD_RAID456)	+= raid456.o
 obj-$(CONFIG_MD_MULTIPATH)	+= multipath.o
 obj-$(CONFIG_MD_FAULTY)		+= faulty.o
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 7199437..f8a9f7a 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -16,6 +16,7 @@
  * wait if count gets too high, wake when it drops to half.
  */
 
+#include <linux/blkdev.h>
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
@@ -26,8 +27,8 @@
 #include <linux/file.h>
 #include <linux/mount.h>
 #include <linux/buffer_head.h>
-#include <linux/raid/md.h>
-#include <linux/raid/bitmap.h>
+#include "md.h"
+#include "bitmap.h"
 
 /* debug macros */
 
@@ -111,9 +112,10 @@ static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int creat
 	unsigned char *mappage;
 
 	if (page >= bitmap->pages) {
-		printk(KERN_ALERT
-			"%s: invalid bitmap page request: %lu (> %lu)\n",
-			bmname(bitmap), page, bitmap->pages-1);
+		/* This can happen if bitmap_start_sync goes beyond
+		 * End-of-device while looking for a whole page.
+		 * It is harmless.
+		 */
 		return -EINVAL;
 	}
 
@@ -265,7 +267,6 @@ static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
 	list_for_each_continue_rcu(pos, &mddev->disks) {
 		rdev = list_entry(pos, mdk_rdev_t, same_set);
 		if (rdev->raid_disk >= 0 &&
-		    test_bit(In_sync, &rdev->flags) &&
 		    !test_bit(Faulty, &rdev->flags)) {
 			/* this is a usable devices */
 			atomic_inc(&rdev->nr_pending);
@@ -297,7 +298,7 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 				    + size/512 > 0)
 					/* bitmap runs in to metadata */
 					goto bad_alignment;
-				if (rdev->data_offset + mddev->size*2
+				if (rdev->data_offset + mddev->dev_sectors
 				    > rdev->sb_start + bitmap->offset)
 					/* data runs in to bitmap */
 					goto bad_alignment;
@@ -570,7 +571,7 @@ static int bitmap_read_sb(struct bitmap *bitmap)
 	else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 		 le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 		reason = "unrecognized superblock version";
-	else if (chunksize < PAGE_SIZE)
+	else if (chunksize < 512)
 		reason = "bitmap chunksize too small";
 	else if ((1 << ffz(~chunksize)) != chunksize)
 		reason = "bitmap chunksize not a power of 2";
@@ -1306,6 +1307,9 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto
 		PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
 		  atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
 	}
+	if (bitmap->mddev->degraded)
+		/* Never clear bits or update events_cleared when degraded */
+		success = 0;
 
 	while (sectors) {
 		int blocks;
@@ -1345,8 +1349,8 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto
 	}
 }
 
-int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
-			int degraded)
+static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
+			       int degraded)
 {
 	bitmap_counter_t *bmc;
 	int rv;
@@ -1374,6 +1378,29 @@ int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
 	return rv;
 }
 
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
+		      int degraded)
+{
+	/* bitmap_start_sync must always report on multiples of whole
+	 * pages, otherwise resync (which is very PAGE_SIZE based) will
+	 * get confused.
+	 * So call __bitmap_start_sync repeatedly (if needed) until
+	 * At least PAGE_SIZE>>9 blocks are covered.
+	 * Return the 'or' of the result.
+	 */
+	int rv = 0;
+	int blocks1;
+
+	*blocks = 0;
+	while (*blocks < (PAGE_SIZE>>9)) {
+		rv |= __bitmap_start_sync(bitmap, offset,
+					  &blocks1, degraded);
+		offset += blocks1;
+		*blocks += blocks1;
+	}
+	return rv;
+}
+
 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
 {
 	bitmap_counter_t *bmc;
@@ -1443,6 +1470,8 @@ void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
 	wait_event(bitmap->mddev->recovery_wait,
 		   atomic_read(&bitmap->mddev->recovery_active) == 0);
 
+	bitmap->mddev->curr_resync_completed = bitmap->mddev->curr_resync;
+	set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
 	sector &= ~((1ULL << CHUNK_BLOCK_SHIFT(bitmap)) - 1);
 	s = 0;
 	while (s < sector && s < bitmap->mddev->resync_max_sectors) {
diff --git a/drivers/md/bitmap.h b/drivers/md/bitmap.h
new file mode 100644
index 0000000..e989006
--- /dev/null
+++ b/drivers/md/bitmap.h
@@ -0,0 +1,288 @@
+/*
+ * bitmap.h: Copyright (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
+ *
+ * additions: Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.
+ */
+#ifndef BITMAP_H
+#define BITMAP_H 1
+
+#define BITMAP_MAJOR_LO 3
+/* version 4 insists the bitmap is in little-endian order
+ * with version 3, it is host-endian which is non-portable
+ */
+#define BITMAP_MAJOR_HI 4
+#define	BITMAP_MAJOR_HOSTENDIAN 3
+
+#define BITMAP_MINOR 39
+
+/*
+ * in-memory bitmap:
+ *
+ * Use 16 bit block counters to track pending writes to each "chunk".
+ * The 2 high order bits are special-purpose, the first is a flag indicating
+ * whether a resync is needed.  The second is a flag indicating whether a
+ * resync is active.
+ * This means that the counter is actually 14 bits:
+ *
+ * +--------+--------+------------------------------------------------+
+ * | resync | resync |               counter                          |
+ * | needed | active |                                                |
+ * |  (0-1) |  (0-1) |              (0-16383)                         |
+ * +--------+--------+------------------------------------------------+
+ *
+ * The "resync needed" bit is set when:
+ *    a '1' bit is read from storage at startup.
+ *    a write request fails on some drives
+ *    a resync is aborted on a chunk with 'resync active' set
+ * It is cleared (and resync-active set) when a resync starts across all drives
+ * of the chunk.
+ *
+ *
+ * The "resync active" bit is set when:
+ *    a resync is started on all drives, and resync_needed is set.
+ *       resync_needed will be cleared (as long as resync_active wasn't already set).
+ * It is cleared when a resync completes.
+ *
+ * The counter counts pending write requests, plus the on-disk bit.
+ * When the counter is '1' and the resync bits are clear, the on-disk
+ * bit can be cleared aswell, thus setting the counter to 0.
+ * When we set a bit, or in the counter (to start a write), if the fields is
+ * 0, we first set the disk bit and set the counter to 1.
+ *
+ * If the counter is 0, the on-disk bit is clear and the stipe is clean
+ * Anything that dirties the stipe pushes the counter to 2 (at least)
+ * and sets the on-disk bit (lazily).
+ * If a periodic sweep find the counter at 2, it is decremented to 1.
+ * If the sweep find the counter at 1, the on-disk bit is cleared and the
+ * counter goes to zero.
+ *
+ * Also, we'll hijack the "map" pointer itself and use it as two 16 bit block
+ * counters as a fallback when "page" memory cannot be allocated:
+ *
+ * Normal case (page memory allocated):
+ *
+ *     page pointer (32-bit)
+ *
+ *     [ ] ------+
+ *               |
+ *               +-------> [   ][   ]..[   ] (4096 byte page == 2048 counters)
+ *                          c1   c2    c2048
+ *
+ * Hijacked case (page memory allocation failed):
+ *
+ *     hijacked page pointer (32-bit)
+ *
+ *     [		  ][		  ] (no page memory allocated)
+ *      counter #1 (16-bit) counter #2 (16-bit)
+ *
+ */
+
+#ifdef __KERNEL__
+
+#define PAGE_BITS (PAGE_SIZE << 3)
+#define PAGE_BIT_SHIFT (PAGE_SHIFT + 3)
+
+typedef __u16 bitmap_counter_t;
+#define COUNTER_BITS 16
+#define COUNTER_BIT_SHIFT 4
+#define COUNTER_BYTE_RATIO (COUNTER_BITS / 8)
+#define COUNTER_BYTE_SHIFT (COUNTER_BIT_SHIFT - 3)
+
+#define NEEDED_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 1)))
+#define RESYNC_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 2)))
+#define COUNTER_MAX ((bitmap_counter_t) RESYNC_MASK - 1)
+#define NEEDED(x) (((bitmap_counter_t) x) & NEEDED_MASK)
+#define RESYNC(x) (((bitmap_counter_t) x) & RESYNC_MASK)
+#define COUNTER(x) (((bitmap_counter_t) x) & COUNTER_MAX)
+
+/* how many counters per page? */
+#define PAGE_COUNTER_RATIO (PAGE_BITS / COUNTER_BITS)
+/* same, except a shift value for more efficient bitops */
+#define PAGE_COUNTER_SHIFT (PAGE_BIT_SHIFT - COUNTER_BIT_SHIFT)
+/* same, except a mask value for more efficient bitops */
+#define PAGE_COUNTER_MASK  (PAGE_COUNTER_RATIO - 1)
+
+#define BITMAP_BLOCK_SIZE 512
+#define BITMAP_BLOCK_SHIFT 9
+
+/* how many blocks per chunk? (this is variable) */
+#define CHUNK_BLOCK_RATIO(bitmap) ((bitmap)->chunksize >> BITMAP_BLOCK_SHIFT)
+#define CHUNK_BLOCK_SHIFT(bitmap) ((bitmap)->chunkshift - BITMAP_BLOCK_SHIFT)
+#define CHUNK_BLOCK_MASK(bitmap) (CHUNK_BLOCK_RATIO(bitmap) - 1)
+
+/* when hijacked, the counters and bits represent even larger "chunks" */
+/* there will be 1024 chunks represented by each counter in the page pointers */
+#define PAGEPTR_BLOCK_RATIO(bitmap) \
+			(CHUNK_BLOCK_RATIO(bitmap) << PAGE_COUNTER_SHIFT >> 1)
+#define PAGEPTR_BLOCK_SHIFT(bitmap) \
+			(CHUNK_BLOCK_SHIFT(bitmap) + PAGE_COUNTER_SHIFT - 1)
+#define PAGEPTR_BLOCK_MASK(bitmap) (PAGEPTR_BLOCK_RATIO(bitmap) - 1)
+
+/*
+ * on-disk bitmap:
+ *
+ * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
+ * file a page at a time. There's a superblock at the start of the file.
+ */
+
+/* map chunks (bits) to file pages - offset by the size of the superblock */
+#define CHUNK_BIT_OFFSET(chunk) ((chunk) + (sizeof(bitmap_super_t) << 3))
+
+#endif
+
+/*
+ * bitmap structures:
+ */
+
+#define BITMAP_MAGIC 0x6d746962
+
+/* use these for bitmap->flags and bitmap->sb->state bit-fields */
+enum bitmap_state {
+	BITMAP_STALE  = 0x002,  /* the bitmap file is out of date or had -EIO */
+	BITMAP_WRITE_ERROR = 0x004, /* A write error has occurred */
+	BITMAP_HOSTENDIAN = 0x8000,
+};
+
+/* the superblock at the front of the bitmap file -- little endian */
+typedef struct bitmap_super_s {
+	__le32 magic;        /*  0  BITMAP_MAGIC */
+	__le32 version;      /*  4  the bitmap major for now, could change... */
+	__u8  uuid[16];      /*  8  128 bit uuid - must match md device uuid */
+	__le64 events;       /* 24  event counter for the bitmap (1)*/
+	__le64 events_cleared;/*32  event counter when last bit cleared (2) */
+	__le64 sync_size;    /* 40  the size of the md device's sync range(3) */
+	__le32 state;        /* 48  bitmap state information */
+	__le32 chunksize;    /* 52  the bitmap chunk size in bytes */
+	__le32 daemon_sleep; /* 56  seconds between disk flushes */
+	__le32 write_behind; /* 60  number of outstanding write-behind writes */
+
+	__u8  pad[256 - 64]; /* set to zero */
+} bitmap_super_t;
+
+/* notes:
+ * (1) This event counter is updated before the eventcounter in the md superblock
+ *    When a bitmap is loaded, it is only accepted if this event counter is equal
+ *    to, or one greater than, the event counter in the superblock.
+ * (2) This event counter is updated when the other one is *if*and*only*if* the
+ *    array is not degraded.  As bits are not cleared when the array is degraded,
+ *    this represents the last time that any bits were cleared.
+ *    If a device is being added that has an event count with this value or
+ *    higher, it is accepted as conforming to the bitmap.
+ * (3)This is the number of sectors represented by the bitmap, and is the range that
+ *    resync happens across.  For raid1 and raid5/6 it is the size of individual
+ *    devices.  For raid10 it is the size of the array.
+ */
+
+#ifdef __KERNEL__
+
+/* the in-memory bitmap is represented by bitmap_pages */
+struct bitmap_page {
+	/*
+	 * map points to the actual memory page
+	 */
+	char *map;
+	/*
+	 * in emergencies (when map cannot be alloced), hijack the map
+	 * pointer and use it as two counters itself
+	 */
+	unsigned int hijacked:1;
+	/*
+	 * count of dirty bits on the page
+	 */
+	unsigned int  count:31;
+};
+
+/* keep track of bitmap file pages that have pending writes on them */
+struct page_list {
+	struct list_head list;
+	struct page *page;
+};
+
+/* the main bitmap structure - one per mddev */
+struct bitmap {
+	struct bitmap_page *bp;
+	unsigned long pages; /* total number of pages in the bitmap */
+	unsigned long missing_pages; /* number of pages not yet allocated */
+
+	mddev_t *mddev; /* the md device that the bitmap is for */
+
+	int counter_bits; /* how many bits per block counter */
+
+	/* bitmap chunksize -- how much data does each bit represent? */
+	unsigned long chunksize;
+	unsigned long chunkshift; /* chunksize = 2^chunkshift (for bitops) */
+	unsigned long chunks; /* total number of data chunks for the array */
+
+	/* We hold a count on the chunk currently being synced, and drop
+	 * it when the last block is started.  If the resync is aborted
+	 * midway, we need to be able to drop that count, so we remember
+	 * the counted chunk..
+	 */
+	unsigned long syncchunk;
+
+	__u64	events_cleared;
+	int need_sync;
+
+	/* bitmap spinlock */
+	spinlock_t lock;
+
+	long offset; /* offset from superblock if file is NULL */
+	struct file *file; /* backing disk file */
+	struct page *sb_page; /* cached copy of the bitmap file superblock */
+	struct page **filemap; /* list of cache pages for the file */
+	unsigned long *filemap_attr; /* attributes associated w/ filemap pages */
+	unsigned long file_pages; /* number of pages in the file */
+	int last_page_size; /* bytes in the last page */
+
+	unsigned long flags;
+
+	int allclean;
+
+	unsigned long max_write_behind; /* write-behind mode */
+	atomic_t behind_writes;
+
+	/*
+	 * the bitmap daemon - periodically wakes up and sweeps the bitmap
+	 * file, cleaning up bits and flushing out pages to disk as necessary
+	 */
+	unsigned long daemon_lastrun; /* jiffies of last run */
+	unsigned long daemon_sleep; /* how many seconds between updates? */
+	unsigned long last_end_sync; /* when we lasted called end_sync to
+				      * update bitmap with resync progress */
+
+	atomic_t pending_writes; /* pending writes to the bitmap file */
+	wait_queue_head_t write_wait;
+	wait_queue_head_t overflow_wait;
+
+};
+
+/* the bitmap API */
+
+/* these are used only by md/bitmap */
+int  bitmap_create(mddev_t *mddev);
+void bitmap_flush(mddev_t *mddev);
+void bitmap_destroy(mddev_t *mddev);
+
+void bitmap_print_sb(struct bitmap *bitmap);
+void bitmap_update_sb(struct bitmap *bitmap);
+
+int  bitmap_setallbits(struct bitmap *bitmap);
+void bitmap_write_all(struct bitmap *bitmap);
+
+void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e);
+
+/* these are exported */
+int bitmap_startwrite(struct bitmap *bitmap, sector_t offset,
+			unsigned long sectors, int behind);
+void bitmap_endwrite(struct bitmap *bitmap, sector_t offset,
+			unsigned long sectors, int success, int behind);
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int degraded);
+void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted);
+void bitmap_close_sync(struct bitmap *bitmap);
+void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector);
+
+void bitmap_unplug(struct bitmap *bitmap);
+void bitmap_daemon_work(struct bitmap *bitmap);
+#endif
+
+#endif
diff --git a/drivers/md/faulty.c b/drivers/md/faulty.c
index 86d9adf..8695809 100644
--- a/drivers/md/faulty.c
+++ b/drivers/md/faulty.c
@@ -62,7 +62,10 @@
 #define	ModeShift	5
 
 #define MaxFault	50
-#include <linux/raid/md.h>
+#include <linux/blkdev.h>
+#include <linux/raid/md_u.h>
+#include "md.h"
+#include <linux/seq_file.h>
 
 
 static void faulty_fail(struct bio *bio, int error)
@@ -280,6 +283,17 @@ static int reconfig(mddev_t *mddev, int layout, int chunk_size)
 	return 0;
 }
 
+static sector_t faulty_size(mddev_t *mddev, sector_t sectors, int raid_disks)
+{
+	WARN_ONCE(raid_disks,
+		  "%s does not support generic reshape\n", __func__);
+
+	if (sectors == 0)
+		return mddev->dev_sectors;
+
+	return sectors;
+}
+
 static int run(mddev_t *mddev)
 {
 	mdk_rdev_t *rdev;
@@ -298,7 +312,7 @@ static int run(mddev_t *mddev)
 	list_for_each_entry(rdev, &mddev->disks, same_set)
 		conf->rdev = rdev;
 
-	mddev->array_sectors = mddev->size * 2;
+	md_set_array_sectors(mddev, faulty_size(mddev, 0, 0));
 	mddev->private = conf;
 
 	reconfig(mddev, mddev->layout, -1);
@@ -325,6 +339,7 @@ static struct mdk_personality faulty_personality =
 	.stop		= stop,
 	.status		= status,
 	.reconfig	= reconfig,
+	.size		= faulty_size,
 };
 
 static int __init raid_init(void)
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 09658b2..7a36e38 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -16,7 +16,11 @@
    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  
 */
 
-#include <linux/raid/linear.h>
+#include <linux/blkdev.h>
+#include <linux/raid/md_u.h>
+#include <linux/seq_file.h>
+#include "md.h"
+#include "linear.h"
 
 /*
  * find which device holds a particular offset 
@@ -97,6 +101,16 @@ static int linear_congested(void *data, int bits)
 	return ret;
 }
 
+static sector_t linear_size(mddev_t *mddev, sector_t sectors, int raid_disks)
+{
+	linear_conf_t *conf = mddev_to_conf(mddev);
+
+	WARN_ONCE(sectors || raid_disks,
+		  "%s does not support generic reshape\n", __func__);
+
+	return conf->array_sectors;
+}
+
 static linear_conf_t *linear_conf(mddev_t *mddev, int raid_disks)
 {
 	linear_conf_t *conf;
@@ -135,8 +149,8 @@ static linear_conf_t *linear_conf(mddev_t *mddev, int raid_disks)
 		    mddev->queue->max_sectors > (PAGE_SIZE>>9))
 			blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
 
-		disk->num_sectors = rdev->size * 2;
-		conf->array_sectors += rdev->size * 2;
+		disk->num_sectors = rdev->sectors;
+		conf->array_sectors += rdev->sectors;
 
 		cnt++;
 	}
@@ -249,7 +263,7 @@ static int linear_run (mddev_t *mddev)
 	if (!conf)
 		return 1;
 	mddev->private = conf;
-	mddev->array_sectors = conf->array_sectors;
+	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
 
 	blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
 	mddev->queue->unplug_fn = linear_unplug;
@@ -283,7 +297,7 @@ static int linear_add(mddev_t *mddev, mdk_rdev_t *rdev)
 	newconf->prev = mddev_to_conf(mddev);
 	mddev->private = newconf;
 	mddev->raid_disks++;
-	mddev->array_sectors = newconf->array_sectors;
+	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
 	set_capacity(mddev->gendisk, mddev->array_sectors);
 	return 0;
 }
@@ -381,6 +395,7 @@ static struct mdk_personality linear_personality =
 	.stop		= linear_stop,
 	.status		= linear_status,
 	.hot_add_disk	= linear_add,
+	.size		= linear_size,
 };
 
 static int __init linear_init (void)
diff --git a/drivers/md/linear.h b/drivers/md/linear.h
new file mode 100644
index 0000000..bf81795
--- /dev/null
+++ b/drivers/md/linear.h
@@ -0,0 +1,29 @@
+#ifndef _LINEAR_H
+#define _LINEAR_H
+
+struct dev_info {
+	mdk_rdev_t	*rdev;
+	sector_t	num_sectors;
+	sector_t	start_sector;
+};
+
+typedef struct dev_info dev_info_t;
+
+struct linear_private_data
+{
+	struct linear_private_data *prev;	/* earlier version */
+	dev_info_t		**hash_table;
+	sector_t		spacing;
+	sector_t		array_sectors;
+	int			sector_shift;	/* shift before dividing
+						 * by spacing
+						 */
+	dev_info_t		disks[0];
+};
+
+
+typedef struct linear_private_data linear_conf_t;
+
+#define mddev_to_conf(mddev) ((linear_conf_t *) mddev->private)
+
+#endif
diff --git a/drivers/md/md.c b/drivers/md/md.c
index a307f87..ed5727c 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -33,9 +33,9 @@
 */
 
 #include <linux/kthread.h>
-#include <linux/raid/md.h>
-#include <linux/raid/bitmap.h>
+#include <linux/blkdev.h>
 #include <linux/sysctl.h>
+#include <linux/seq_file.h>
 #include <linux/buffer_head.h> /* for invalidate_bdev */
 #include <linux/poll.h>
 #include <linux/ctype.h>
@@ -45,11 +45,10 @@
 #include <linux/reboot.h>
 #include <linux/file.h>
 #include <linux/delay.h>
-
-#define MAJOR_NR MD_MAJOR
-
-/* 63 partitions with the alternate major number (mdp) */
-#define MdpMinorShift 6
+#include <linux/raid/md_p.h>
+#include <linux/raid/md_u.h>
+#include "md.h"
+#include "bitmap.h"
 
 #define DEBUG 0
 #define dprintk(x...) ((void)(DEBUG && printk(x)))
@@ -202,12 +201,68 @@ static DEFINE_SPINLOCK(all_mddevs_lock);
 		)
 
 
-static int md_fail_request(struct request_queue *q, struct bio *bio)
+/* Rather than calling directly into the personality make_request function,
+ * IO requests come here first so that we can check if the device is
+ * being suspended pending a reconfiguration.
+ * We hold a refcount over the call to ->make_request.  By the time that
+ * call has finished, the bio has been linked into some internal structure
+ * and so is visible to ->quiesce(), so we don't need the refcount any more.
+ */
+static int md_make_request(struct request_queue *q, struct bio *bio)
 {
-	bio_io_error(bio);
-	return 0;
+	mddev_t *mddev = q->queuedata;
+	int rv;
+	if (mddev == NULL || mddev->pers == NULL) {
+		bio_io_error(bio);
+		return 0;
+	}
+	rcu_read_lock();
+	if (mddev->suspended) {
+		DEFINE_WAIT(__wait);
+		for (;;) {
+			prepare_to_wait(&mddev->sb_wait, &__wait,
+					TASK_UNINTERRUPTIBLE);
+			if (!mddev->suspended)
+				break;
+			rcu_read_unlock();
+			schedule();
+			rcu_read_lock();
+		}
+		finish_wait(&mddev->sb_wait, &__wait);
+	}
+	atomic_inc(&mddev->active_io);
+	rcu_read_unlock();
+	rv = mddev->pers->make_request(q, bio);
+	if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
+		wake_up(&mddev->sb_wait);
+
+	return rv;
+}
+
+static void mddev_suspend(mddev_t *mddev)
+{
+	BUG_ON(mddev->suspended);
+	mddev->suspended = 1;
+	synchronize_rcu();
+	wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
+	mddev->pers->quiesce(mddev, 1);
+	md_unregister_thread(mddev->thread);
+	mddev->thread = NULL;
+	/* we now know that no code is executing in the personality module,
+	 * except possibly the tail end of a ->bi_end_io function, but that
+	 * is certain to complete before the module has a chance to get
+	 * unloaded
+	 */
+}
+
+static void mddev_resume(mddev_t *mddev)
+{
+	mddev->suspended = 0;
+	wake_up(&mddev->sb_wait);
+	mddev->pers->quiesce(mddev, 0);
 }
 
+
 static inline mddev_t *mddev_get(mddev_t *mddev)
 {
 	atomic_inc(&mddev->active);
@@ -310,6 +365,7 @@ static mddev_t * mddev_find(dev_t unit)
 	init_timer(&new->safemode_timer);
 	atomic_set(&new->active, 1);
 	atomic_set(&new->openers, 0);
+	atomic_set(&new->active_io, 0);
 	spin_lock_init(&new->write_lock);
 	init_waitqueue_head(&new->sb_wait);
 	init_waitqueue_head(&new->recovery_wait);
@@ -326,6 +382,11 @@ static inline int mddev_lock(mddev_t * mddev)
 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
 }
 
+static inline int mddev_is_locked(mddev_t *mddev)
+{
+	return mutex_is_locked(&mddev->reconfig_mutex);
+}
+
 static inline int mddev_trylock(mddev_t * mddev)
 {
 	return mutex_trylock(&mddev->reconfig_mutex);
@@ -409,7 +470,7 @@ static void free_disk_sb(mdk_rdev_t * rdev)
 		rdev->sb_loaded = 0;
 		rdev->sb_page = NULL;
 		rdev->sb_start = 0;
-		rdev->size = 0;
+		rdev->sectors = 0;
 	}
 }
 
@@ -775,9 +836,9 @@ static int super_90_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version
 		else 
 			ret = 0;
 	}
-	rdev->size = calc_num_sectors(rdev, sb->chunk_size) / 2;
+	rdev->sectors = calc_num_sectors(rdev, sb->chunk_size);
 
-	if (rdev->size < sb->size && sb->level > 1)
+	if (rdev->sectors < sb->size * 2 && sb->level > 1)
 		/* "this cannot possibly happen" ... */
 		ret = -EINVAL;
 
@@ -812,7 +873,7 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
 		mddev->clevel[0] = 0;
 		mddev->layout = sb->layout;
 		mddev->raid_disks = sb->raid_disks;
-		mddev->size = sb->size;
+		mddev->dev_sectors = sb->size * 2;
 		mddev->events = ev1;
 		mddev->bitmap_offset = 0;
 		mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
@@ -926,7 +987,7 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
 
 	sb->ctime = mddev->ctime;
 	sb->level = mddev->level;
-	sb->size  = mddev->size;
+	sb->size = mddev->dev_sectors / 2;
 	sb->raid_disks = mddev->raid_disks;
 	sb->md_minor = mddev->md_minor;
 	sb->not_persistent = 0;
@@ -1024,7 +1085,7 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
 static unsigned long long
 super_90_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
 {
-	if (num_sectors && num_sectors < rdev->mddev->size * 2)
+	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
 		return 0; /* component must fit device */
 	if (rdev->mddev->bitmap_offset)
 		return 0; /* can't move bitmap */
@@ -1180,16 +1241,17 @@ static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
 			ret = 0;
 	}
 	if (minor_version)
-		rdev->size = ((rdev->bdev->bd_inode->i_size>>9) - le64_to_cpu(sb->data_offset)) / 2;
+		rdev->sectors = (rdev->bdev->bd_inode->i_size >> 9) -
+			le64_to_cpu(sb->data_offset);
 	else
-		rdev->size = rdev->sb_start / 2;
-	if (rdev->size < le64_to_cpu(sb->data_size)/2)
+		rdev->sectors = rdev->sb_start;
+	if (rdev->sectors < le64_to_cpu(sb->data_size))
 		return -EINVAL;
-	rdev->size = le64_to_cpu(sb->data_size)/2;
+	rdev->sectors = le64_to_cpu(sb->data_size);
 	if (le32_to_cpu(sb->chunksize))
-		rdev->size &= ~((sector_t)le32_to_cpu(sb->chunksize)/2 - 1);
+		rdev->sectors &= ~((sector_t)le32_to_cpu(sb->chunksize) - 1);
 
-	if (le64_to_cpu(sb->size) > rdev->size*2)
+	if (le64_to_cpu(sb->size) > rdev->sectors)
 		return -EINVAL;
 	return ret;
 }
@@ -1216,7 +1278,7 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
 		mddev->clevel[0] = 0;
 		mddev->layout = le32_to_cpu(sb->layout);
 		mddev->raid_disks = le32_to_cpu(sb->raid_disks);
-		mddev->size = le64_to_cpu(sb->size)/2;
+		mddev->dev_sectors = le64_to_cpu(sb->size);
 		mddev->events = ev1;
 		mddev->bitmap_offset = 0;
 		mddev->default_bitmap_offset = 1024 >> 9;
@@ -1312,7 +1374,7 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
 	sb->cnt_corrected_read = cpu_to_le32(atomic_read(&rdev->corrected_errors));
 
 	sb->raid_disks = cpu_to_le32(mddev->raid_disks);
-	sb->size = cpu_to_le64(mddev->size<<1);
+	sb->size = cpu_to_le64(mddev->dev_sectors);
 
 	if (mddev->bitmap && mddev->bitmap_file == NULL) {
 		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);
@@ -1320,10 +1382,15 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
 	}
 
 	if (rdev->raid_disk >= 0 &&
-	    !test_bit(In_sync, &rdev->flags) &&
-	    rdev->recovery_offset > 0) {
-		sb->feature_map |= cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
-		sb->recovery_offset = cpu_to_le64(rdev->recovery_offset);
+	    !test_bit(In_sync, &rdev->flags)) {
+		if (mddev->curr_resync_completed > rdev->recovery_offset)
+			rdev->recovery_offset = mddev->curr_resync_completed;
+		if (rdev->recovery_offset > 0) {
+			sb->feature_map |=
+				cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
+			sb->recovery_offset =
+				cpu_to_le64(rdev->recovery_offset);
+		}
 	}
 
 	if (mddev->reshape_position != MaxSector) {
@@ -1365,7 +1432,7 @@ super_1_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
 {
 	struct mdp_superblock_1 *sb;
 	sector_t max_sectors;
-	if (num_sectors && num_sectors < rdev->mddev->size * 2)
+	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
 		return 0; /* component must fit device */
 	if (rdev->sb_start < rdev->data_offset) {
 		/* minor versions 1 and 2; superblock before data */
@@ -1381,7 +1448,7 @@ super_1_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
 		sector_t sb_start;
 		sb_start = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
 		sb_start &= ~(sector_t)(4*2 - 1);
-		max_sectors = rdev->size * 2 + sb_start - rdev->sb_start;
+		max_sectors = rdev->sectors + sb_start - rdev->sb_start;
 		if (!num_sectors || num_sectors > max_sectors)
 			num_sectors = max_sectors;
 		rdev->sb_start = sb_start;
@@ -1433,6 +1500,38 @@ static int match_mddev_units(mddev_t *mddev1, mddev_t *mddev2)
 
 static LIST_HEAD(pending_raid_disks);
 
+static void md_integrity_check(mdk_rdev_t *rdev, mddev_t *mddev)
+{
+	struct mdk_personality *pers = mddev->pers;
+	struct gendisk *disk = mddev->gendisk;
+	struct blk_integrity *bi_rdev = bdev_get_integrity(rdev->bdev);
+	struct blk_integrity *bi_mddev = blk_get_integrity(disk);
+
+	/* Data integrity passthrough not supported on RAID 4, 5 and 6 */
+	if (pers && pers->level >= 4 && pers->level <= 6)
+		return;
+
+	/* If rdev is integrity capable, register profile for mddev */
+	if (!bi_mddev && bi_rdev) {
+		if (blk_integrity_register(disk, bi_rdev))
+			printk(KERN_ERR "%s: %s Could not register integrity!\n",
+			       __func__, disk->disk_name);
+		else
+			printk(KERN_NOTICE "Enabling data integrity on %s\n",
+			       disk->disk_name);
+		return;
+	}
+
+	/* Check that mddev and rdev have matching profiles */
+	if (blk_integrity_compare(disk, rdev->bdev->bd_disk) < 0) {
+		printk(KERN_ERR "%s: %s/%s integrity mismatch!\n", __func__,
+		       disk->disk_name, rdev->bdev->bd_disk->disk_name);
+		printk(KERN_NOTICE "Disabling data integrity on %s\n",
+		       disk->disk_name);
+		blk_integrity_unregister(disk);
+	}
+}
+
 static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
 {
 	char b[BDEVNAME_SIZE];
@@ -1449,8 +1548,9 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
 	if (find_rdev(mddev, rdev->bdev->bd_dev))
 		return -EEXIST;
 
-	/* make sure rdev->size exceeds mddev->size */
-	if (rdev->size && (mddev->size == 0 || rdev->size < mddev->size)) {
+	/* make sure rdev->sectors exceeds mddev->dev_sectors */
+	if (rdev->sectors && (mddev->dev_sectors == 0 ||
+			rdev->sectors < mddev->dev_sectors)) {
 		if (mddev->pers) {
 			/* Cannot change size, so fail
 			 * If mddev->level <= 0, then we don't care
@@ -1459,7 +1559,7 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
 			if (mddev->level > 0)
 				return -ENOSPC;
 		} else
-			mddev->size = rdev->size;
+			mddev->dev_sectors = rdev->sectors;
 	}
 
 	/* Verify rdev->desc_nr is unique.
@@ -1503,6 +1603,8 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
 
 	/* May as well allow recovery to be retried once */
 	mddev->recovery_disabled = 0;
+
+	md_integrity_check(rdev, mddev);
 	return 0;
 
  fail:
@@ -1713,8 +1815,8 @@ static void print_sb_1(struct mdp_superblock_1 *sb)
 static void print_rdev(mdk_rdev_t *rdev, int major_version)
 {
 	char b[BDEVNAME_SIZE];
-	printk(KERN_INFO "md: rdev %s, SZ:%08llu F:%d S:%d DN:%u\n",
-		bdevname(rdev->bdev,b), (unsigned long long)rdev->size,
+	printk(KERN_INFO "md: rdev %s, Sect:%08llu F:%d S:%d DN:%u\n",
+		bdevname(rdev->bdev, b), (unsigned long long)rdev->sectors,
 	        test_bit(Faulty, &rdev->flags), test_bit(In_sync, &rdev->flags),
 	        rdev->desc_nr);
 	if (rdev->sb_loaded) {
@@ -2153,7 +2255,7 @@ offset_store(mdk_rdev_t *rdev, const char *buf, size_t len)
 		return -EINVAL;
 	if (rdev->mddev->pers && rdev->raid_disk >= 0)
 		return -EBUSY;
-	if (rdev->size && rdev->mddev->external)
+	if (rdev->sectors && rdev->mddev->external)
 		/* Must set offset before size, so overlap checks
 		 * can be sane */
 		return -EBUSY;
@@ -2167,7 +2269,7 @@ __ATTR(offset, S_IRUGO|S_IWUSR, offset_show, offset_store);
 static ssize_t
 rdev_size_show(mdk_rdev_t *rdev, char *page)
 {
-	return sprintf(page, "%llu\n", (unsigned long long)rdev->size);
+	return sprintf(page, "%llu\n", (unsigned long long)rdev->sectors / 2);
 }
 
 static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
@@ -2180,34 +2282,52 @@ static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
 	return 1;
 }
 
+static int strict_blocks_to_sectors(const char *buf, sector_t *sectors)
+{
+	unsigned long long blocks;
+	sector_t new;
+
+	if (strict_strtoull(buf, 10, &blocks) < 0)
+		return -EINVAL;
+
+	if (blocks & 1ULL << (8 * sizeof(blocks) - 1))
+		return -EINVAL; /* sector conversion overflow */
+
+	new = blocks * 2;
+	if (new != blocks * 2)
+		return -EINVAL; /* unsigned long long to sector_t overflow */
+
+	*sectors = new;
+	return 0;
+}
+
 static ssize_t
 rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
 {
-	unsigned long long size;
-	unsigned long long oldsize = rdev->size;
 	mddev_t *my_mddev = rdev->mddev;
+	sector_t oldsectors = rdev->sectors;
+	sector_t sectors;
 
-	if (strict_strtoull(buf, 10, &size) < 0)
+	if (strict_blocks_to_sectors(buf, &sectors) < 0)
 		return -EINVAL;
 	if (my_mddev->pers && rdev->raid_disk >= 0) {
 		if (my_mddev->persistent) {
-			size = super_types[my_mddev->major_version].
-				rdev_size_change(rdev, size * 2);
-			if (!size)
+			sectors = super_types[my_mddev->major_version].
+				rdev_size_change(rdev, sectors);
+			if (!sectors)
 				return -EBUSY;
-		} else if (!size) {
-			size = (rdev->bdev->bd_inode->i_size >> 10);
-			size -= rdev->data_offset/2;
-		}
+		} else if (!sectors)
+			sectors = (rdev->bdev->bd_inode->i_size >> 9) -
+				rdev->data_offset;
 	}
-	if (size < my_mddev->size)
+	if (sectors < my_mddev->dev_sectors)
 		return -EINVAL; /* component must fit device */
 
-	rdev->size = size;
-	if (size > oldsize && my_mddev->external) {
+	rdev->sectors = sectors;
+	if (sectors > oldsectors && my_mddev->external) {
 		/* need to check that all other rdevs with the same ->bdev
 		 * do not overlap.  We need to unlock the mddev to avoid
-		 * a deadlock.  We have already changed rdev->size, and if
+		 * a deadlock.  We have already changed rdev->sectors, and if
 		 * we have to change it back, we will have the lock again.
 		 */
 		mddev_t *mddev;
@@ -2223,9 +2343,9 @@ rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
 				if (test_bit(AllReserved, &rdev2->flags) ||
 				    (rdev->bdev == rdev2->bdev &&
 				     rdev != rdev2 &&
-				     overlaps(rdev->data_offset, rdev->size * 2,
+				     overlaps(rdev->data_offset, rdev->sectors,
 					      rdev2->data_offset,
-					      rdev2->size * 2))) {
+					      rdev2->sectors))) {
 					overlap = 1;
 					break;
 				}
@@ -2239,11 +2359,11 @@ rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
 		if (overlap) {
 			/* Someone else could have slipped in a size
 			 * change here, but doing so is just silly.
-			 * We put oldsize back because we *know* it is
+			 * We put oldsectors back because we *know* it is
 			 * safe, and trust userspace not to race with
 			 * itself
 			 */
-			rdev->size = oldsize;
+			rdev->sectors = oldsectors;
 			return -EBUSY;
 		}
 	}
@@ -2547,18 +2667,101 @@ level_show(mddev_t *mddev, char *page)
 static ssize_t
 level_store(mddev_t *mddev, const char *buf, size_t len)
 {
+	char level[16];
 	ssize_t rv = len;
-	if (mddev->pers)
+	struct mdk_personality *pers;
+	void *priv;
+
+	if (mddev->pers == NULL) {
+		if (len == 0)
+			return 0;
+		if (len >= sizeof(mddev->clevel))
+			return -ENOSPC;
+		strncpy(mddev->clevel, buf, len);
+		if (mddev->clevel[len-1] == '\n')
+			len--;
+		mddev->clevel[len] = 0;
+		mddev->level = LEVEL_NONE;
+		return rv;
+	}
+
+	/* request to change the personality.  Need to ensure:
+	 *  - array is not engaged in resync/recovery/reshape
+	 *  - old personality can be suspended
+	 *  - new personality will access other array.
+	 */
+
+	if (mddev->sync_thread || mddev->reshape_position != MaxSector)
 		return -EBUSY;
-	if (len == 0)
-		return 0;
-	if (len >= sizeof(mddev->clevel))
-		return -ENOSPC;
-	strncpy(mddev->clevel, buf, len);
-	if (mddev->clevel[len-1] == '\n')
+
+	if (!mddev->pers->quiesce) {
+		printk(KERN_WARNING "md: %s: %s does not support online personality change\n",
+		       mdname(mddev), mddev->pers->name);
+		return -EINVAL;
+	}
+
+	/* Now find the new personality */
+	if (len == 0 || len >= sizeof(level))
+		return -EINVAL;
+	strncpy(level, buf, len);
+	if (level[len-1] == '\n')
 		len--;
-	mddev->clevel[len] = 0;
-	mddev->level = LEVEL_NONE;
+	level[len] = 0;
+
+	request_module("md-%s", level);
+	spin_lock(&pers_lock);
+	pers = find_pers(LEVEL_NONE, level);
+	if (!pers || !try_module_get(pers->owner)) {
+		spin_unlock(&pers_lock);
+		printk(KERN_WARNING "md: personality %s not loaded\n", level);
+		return -EINVAL;
+	}
+	spin_unlock(&pers_lock);
+
+	if (pers == mddev->pers) {
+		/* Nothing to do! */
+		module_put(pers->owner);
+		return rv;
+	}
+	if (!pers->takeover) {
+		module_put(pers->owner);
+		printk(KERN_WARNING "md: %s: %s does not support personality takeover\n",
+		       mdname(mddev), level);
+		return -EINVAL;
+	}
+
+	/* ->takeover must set new_* and/or delta_disks
+	 * if it succeeds, and may set them when it fails.
+	 */
+	priv = pers->takeover(mddev);
+	if (IS_ERR(priv)) {
+		mddev->new_level = mddev->level;
+		mddev->new_layout = mddev->layout;
+		mddev->new_chunk = mddev->chunk_size;
+		mddev->raid_disks -= mddev->delta_disks;
+		mddev->delta_disks = 0;
+		module_put(pers->owner);
+		printk(KERN_WARNING "md: %s: %s would not accept array\n",
+		       mdname(mddev), level);
+		return PTR_ERR(priv);
+	}
+
+	/* Looks like we have a winner */
+	mddev_suspend(mddev);
+	mddev->pers->stop(mddev);
+	module_put(mddev->pers->owner);
+	mddev->pers = pers;
+	mddev->private = priv;
+	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
+	mddev->level = mddev->new_level;
+	mddev->layout = mddev->new_layout;
+	mddev->chunk_size = mddev->new_chunk;
+	mddev->delta_disks = 0;
+	pers->run(mddev);
+	mddev_resume(mddev);
+	set_bit(MD_CHANGE_DEVS, &mddev->flags);
+	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	md_wakeup_thread(mddev->thread);
 	return rv;
 }
 
@@ -2586,12 +2789,18 @@ layout_store(mddev_t *mddev, const char *buf, size_t len)
 	if (!*buf || (*e && *e != '\n'))
 		return -EINVAL;
 
-	if (mddev->pers)
-		return -EBUSY;
-	if (mddev->reshape_position != MaxSector)
+	if (mddev->pers) {
+		int err;
+		if (mddev->pers->reconfig == NULL)
+			return -EBUSY;
+		err = mddev->pers->reconfig(mddev, n, -1);
+		if (err)
+			return err;
+	} else {
 		mddev->new_layout = n;
-	else
-		mddev->layout = n;
+		if (mddev->reshape_position == MaxSector)
+			mddev->layout = n;
+	}
 	return len;
 }
 static struct md_sysfs_entry md_layout =
@@ -2648,19 +2857,24 @@ chunk_size_show(mddev_t *mddev, char *page)
 static ssize_t
 chunk_size_store(mddev_t *mddev, const char *buf, size_t len)
 {
-	/* can only set chunk_size if array is not yet active */
 	char *e;
 	unsigned long n = simple_strtoul(buf, &e, 10);
 
 	if (!*buf || (*e && *e != '\n'))
 		return -EINVAL;
 
-	if (mddev->pers)
-		return -EBUSY;
-	else if (mddev->reshape_position != MaxSector)
+	if (mddev->pers) {
+		int err;
+		if (mddev->pers->reconfig == NULL)
+			return -EBUSY;
+		err = mddev->pers->reconfig(mddev, -1, n);
+		if (err)
+			return err;
+	} else {
 		mddev->new_chunk = n;
-	else
-		mddev->chunk_size = n;
+		if (mddev->reshape_position == MaxSector)
+			mddev->chunk_size = n;
+	}
 	return len;
 }
 static struct md_sysfs_entry md_chunk_size =
@@ -2669,6 +2883,8 @@ __ATTR(chunk_size, S_IRUGO|S_IWUSR, chunk_size_show, chunk_size_store);
 static ssize_t
 resync_start_show(mddev_t *mddev, char *page)
 {
+	if (mddev->recovery_cp == MaxSector)
+		return sprintf(page, "none\n");
 	return sprintf(page, "%llu\n", (unsigned long long)mddev->recovery_cp);
 }
 
@@ -2766,7 +2982,7 @@ array_state_show(mddev_t *mddev, char *page)
 	else {
 		if (list_empty(&mddev->disks) &&
 		    mddev->raid_disks == 0 &&
-		    mddev->size == 0)
+		    mddev->dev_sectors == 0)
 			st = clear;
 		else
 			st = inactive;
@@ -2973,7 +3189,8 @@ __ATTR(bitmap_set_bits, S_IWUSR, null_show, bitmap_store);
 static ssize_t
 size_show(mddev_t *mddev, char *page)
 {
-	return sprintf(page, "%llu\n", (unsigned long long)mddev->size);
+	return sprintf(page, "%llu\n",
+		(unsigned long long)mddev->dev_sectors / 2);
 }
 
 static int update_size(mddev_t *mddev, sector_t num_sectors);
@@ -2985,20 +3202,18 @@ size_store(mddev_t *mddev, const char *buf, size_t len)
 	 * not increase it (except from 0).
 	 * If array is active, we can try an on-line resize
 	 */
-	char *e;
-	int err = 0;
-	unsigned long long size = simple_strtoull(buf, &e, 10);
-	if (!*buf || *buf == '\n' ||
-	    (*e && *e != '\n'))
-		return -EINVAL;
+	sector_t sectors;
+	int err = strict_blocks_to_sectors(buf, &sectors);
 
+	if (err < 0)
+		return err;
 	if (mddev->pers) {
-		err = update_size(mddev, size * 2);
+		err = update_size(mddev, sectors);
 		md_update_sb(mddev, 1);
 	} else {
-		if (mddev->size == 0 ||
-		    mddev->size > size)
-			mddev->size = size;
+		if (mddev->dev_sectors == 0 ||
+		    mddev->dev_sectors > sectors)
+			mddev->dev_sectors = sectors;
 		else
 			err = -ENOSPC;
 	}
@@ -3251,6 +3466,8 @@ static ssize_t
 sync_speed_show(mddev_t *mddev, char *page)
 {
 	unsigned long resync, dt, db;
+	if (mddev->curr_resync == 0)
+		return sprintf(page, "none\n");
 	resync = mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active);
 	dt = (jiffies - mddev->resync_mark) / HZ;
 	if (!dt) dt++;
@@ -3263,15 +3480,15 @@ static struct md_sysfs_entry md_sync_speed = __ATTR_RO(sync_speed);
 static ssize_t
 sync_completed_show(mddev_t *mddev, char *page)
 {
-	unsigned long max_blocks, resync;
+	unsigned long max_sectors, resync;
 
 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
-		max_blocks = mddev->resync_max_sectors;
+		max_sectors = mddev->resync_max_sectors;
 	else
-		max_blocks = mddev->size << 1;
+		max_sectors = mddev->dev_sectors;
 
 	resync = (mddev->curr_resync - atomic_read(&mddev->recovery_active));
-	return sprintf(page, "%lu / %lu\n", resync, max_blocks);
+	return sprintf(page, "%lu / %lu\n", resync, max_sectors);
 }
 
 static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);
@@ -3431,6 +3648,57 @@ static struct md_sysfs_entry md_reshape_position =
 __ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
        reshape_position_store);
 
+static ssize_t
+array_size_show(mddev_t *mddev, char *page)
+{
+	if (mddev->external_size)
+		return sprintf(page, "%llu\n",
+			       (unsigned long long)mddev->array_sectors/2);
+	else
+		return sprintf(page, "default\n");
+}
+
+static ssize_t
+array_size_store(mddev_t *mddev, const char *buf, size_t len)
+{
+	sector_t sectors;
+
+	if (strncmp(buf, "default", 7) == 0) {
+		if (mddev->pers)
+			sectors = mddev->pers->size(mddev, 0, 0);
+		else
+			sectors = mddev->array_sectors;
+
+		mddev->external_size = 0;
+	} else {
+		if (strict_blocks_to_sectors(buf, &sectors) < 0)
+			return -EINVAL;
+		if (mddev->pers && mddev->pers->size(mddev, 0, 0) < sectors)
+			return -EINVAL;
+
+		mddev->external_size = 1;
+	}
+
+	mddev->array_sectors = sectors;
+	set_capacity(mddev->gendisk, mddev->array_sectors);
+	if (mddev->pers) {
+		struct block_device *bdev = bdget_disk(mddev->gendisk, 0);
+
+		if (bdev) {
+			mutex_lock(&bdev->bd_inode->i_mutex);
+			i_size_write(bdev->bd_inode,
+				     (loff_t)mddev->array_sectors << 9);
+			mutex_unlock(&bdev->bd_inode->i_mutex);
+			bdput(bdev);
+		}
+	}
+
+	return len;
+}
+
+static struct md_sysfs_entry md_array_size =
+__ATTR(array_size, S_IRUGO|S_IWUSR, array_size_show,
+       array_size_store);
 
 static struct attribute *md_default_attrs[] = {
 	&md_level.attr,
@@ -3444,6 +3712,7 @@ static struct attribute *md_default_attrs[] = {
 	&md_safe_delay.attr,
 	&md_array_state.attr,
 	&md_reshape_position.attr,
+	&md_array_size.attr,
 	NULL,
 };
 
@@ -3602,10 +3871,12 @@ static int md_alloc(dev_t dev, char *name)
 		mddev_put(mddev);
 		return -ENOMEM;
 	}
+	mddev->queue->queuedata = mddev;
+
 	/* Can be unlocked because the queue is new: no concurrency */
 	queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, mddev->queue);
 
-	blk_queue_make_request(mddev->queue, md_fail_request);
+	blk_queue_make_request(mddev->queue, md_make_request);
 
 	disk = alloc_disk(1 << shift);
 	if (!disk) {
@@ -3731,13 +4002,13 @@ static int do_md_run(mddev_t * mddev)
 		list_for_each_entry(rdev, &mddev->disks, same_set) {
 			if (test_bit(Faulty, &rdev->flags))
 				continue;
-			if (rdev->size < chunk_size / 1024) {
+			if (rdev->sectors < chunk_size / 512) {
 				printk(KERN_WARNING
 					"md: Dev %s smaller than chunk_size:"
-					" %lluk < %dk\n",
+					" %llu < %d\n",
 					bdevname(rdev->bdev,b),
-					(unsigned long long)rdev->size,
-					chunk_size / 1024);
+					(unsigned long long)rdev->sectors,
+					chunk_size / 512);
 				return -EINVAL;
 			}
 		}
@@ -3761,11 +4032,11 @@ static int do_md_run(mddev_t * mddev)
 
 		/* perform some consistency tests on the device.
 		 * We don't want the data to overlap the metadata,
-		 * Internal Bitmap issues has handled elsewhere.
+		 * Internal Bitmap issues have been handled elsewhere.
 		 */
 		if (rdev->data_offset < rdev->sb_start) {
-			if (mddev->size &&
-			    rdev->data_offset + mddev->size*2
+			if (mddev->dev_sectors &&
+			    rdev->data_offset + mddev->dev_sectors
 			    > rdev->sb_start) {
 				printk("md: %s: data overlaps metadata\n",
 				       mdname(mddev));
@@ -3801,9 +4072,16 @@ static int do_md_run(mddev_t * mddev)
 	}
 	mddev->pers = pers;
 	spin_unlock(&pers_lock);
-	mddev->level = pers->level;
+	if (mddev->level != pers->level) {
+		mddev->level = pers->level;
+		mddev->new_level = pers->level;
+	}
 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
 
+	if (pers->level >= 4 && pers->level <= 6)
+		/* Cannot support integrity (yet) */
+		blk_integrity_unregister(mddev->gendisk);
+
 	if (mddev->reshape_position != MaxSector &&
 	    pers->start_reshape == NULL) {
 		/* This personality cannot handle reshaping... */
@@ -3843,7 +4121,9 @@ static int do_md_run(mddev_t * mddev)
 	}
 
 	mddev->recovery = 0;
-	mddev->resync_max_sectors = mddev->size << 1; /* may be over-ridden by personality */
+	/* may be over-ridden by personality */
+	mddev->resync_max_sectors = mddev->dev_sectors;
+
 	mddev->barriers_work = 1;
 	mddev->ok_start_degraded = start_dirty_degraded;
 
@@ -3853,7 +4133,17 @@ static int do_md_run(mddev_t * mddev)
 	err = mddev->pers->run(mddev);
 	if (err)
 		printk(KERN_ERR "md: pers->run() failed ...\n");
-	else if (mddev->pers->sync_request) {
+	else if (mddev->pers->size(mddev, 0, 0) < mddev->array_sectors) {
+		WARN_ONCE(!mddev->external_size, "%s: default size too small,"
+			  " but 'external_size' not in effect?\n", __func__);
+		printk(KERN_ERR
+		       "md: invalid array_size %llu > default size %llu\n",
+		       (unsigned long long)mddev->array_sectors / 2,
+		       (unsigned long long)mddev->pers->size(mddev, 0, 0) / 2);
+		err = -EINVAL;
+		mddev->pers->stop(mddev);
+	}
+	if (err == 0 && mddev->pers->sync_request) {
 		err = bitmap_create(mddev);
 		if (err) {
 			printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
@@ -3899,16 +4189,6 @@ static int do_md_run(mddev_t * mddev)
 
 	set_capacity(disk, mddev->array_sectors);
 
-	/* If we call blk_queue_make_request here, it will
-	 * re-initialise max_sectors etc which may have been
-	 * refined inside -> run.  So just set the bits we need to set.
-	 * Most initialisation happended when we called
-	 * blk_queue_make_request(..., md_fail_request)
-	 * earlier.
-	 */
-	mddev->queue->queuedata = mddev;
-	mddev->queue->make_request_fn = mddev->pers->make_request;
-
 	/* If there is a partially-recovered drive we need to
 	 * start recovery here.  If we leave it to md_check_recovery,
 	 * it will remove the drives and not do the right thing
@@ -4038,7 +4318,7 @@ static int do_md_stop(mddev_t * mddev, int mode, int is_open)
 			md_super_wait(mddev);
 			if (mddev->ro)
 				set_disk_ro(disk, 0);
-			blk_queue_make_request(mddev->queue, md_fail_request);
+
 			mddev->pers->stop(mddev);
 			mddev->queue->merge_bvec_fn = NULL;
 			mddev->queue->unplug_fn = NULL;
@@ -4095,7 +4375,8 @@ static int do_md_stop(mddev_t * mddev, int mode, int is_open)
 		export_array(mddev);
 
 		mddev->array_sectors = 0;
-		mddev->size = 0;
+		mddev->external_size = 0;
+		mddev->dev_sectors = 0;
 		mddev->raid_disks = 0;
 		mddev->recovery_cp = 0;
 		mddev->resync_min = 0;
@@ -4135,6 +4416,7 @@ static int do_md_stop(mddev_t * mddev, int mode, int is_open)
 		printk(KERN_INFO "md: %s switched to read-only mode.\n",
 			mdname(mddev));
 	err = 0;
+	blk_integrity_unregister(disk);
 	md_new_event(mddev);
 	sysfs_notify_dirent(mddev->sysfs_state);
 out:
@@ -4300,8 +4582,8 @@ static int get_array_info(mddev_t * mddev, void __user * arg)
 	info.patch_version = MD_PATCHLEVEL_VERSION;
 	info.ctime         = mddev->ctime;
 	info.level         = mddev->level;
-	info.size          = mddev->size;
-	if (info.size != mddev->size) /* overflow */
+	info.size          = mddev->dev_sectors / 2;
+	if (info.size != mddev->dev_sectors / 2) /* overflow */
 		info.size = -1;
 	info.nr_disks      = nr;
 	info.raid_disks    = mddev->raid_disks;
@@ -4480,6 +4762,8 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
 		clear_bit(In_sync, &rdev->flags); /* just to be sure */
 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
 			set_bit(WriteMostly, &rdev->flags);
+		else
+			clear_bit(WriteMostly, &rdev->flags);
 
 		rdev->raid_disk = -1;
 		err = bind_rdev_to_array(rdev, mddev);
@@ -4543,7 +4827,7 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
 			rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
 		} else 
 			rdev->sb_start = calc_dev_sboffset(rdev->bdev);
-		rdev->size = calc_num_sectors(rdev, mddev->chunk_size) / 2;
+		rdev->sectors = calc_num_sectors(rdev, mddev->chunk_size);
 
 		err = bind_rdev_to_array(rdev, mddev);
 		if (err) {
@@ -4613,7 +4897,7 @@ static int hot_add_disk(mddev_t * mddev, dev_t dev)
 	else
 		rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
 
-	rdev->size = calc_num_sectors(rdev, mddev->chunk_size) / 2;
+	rdev->sectors = calc_num_sectors(rdev, mddev->chunk_size);
 
 	if (test_bit(Faulty, &rdev->flags)) {
 		printk(KERN_WARNING 
@@ -4749,7 +5033,7 @@ static int set_array_info(mddev_t * mddev, mdu_array_info_t *info)
 
 	mddev->level         = info->level;
 	mddev->clevel[0]     = 0;
-	mddev->size          = info->size;
+	mddev->dev_sectors   = 2 * (sector_t)info->size;
 	mddev->raid_disks    = info->raid_disks;
 	/* don't set md_minor, it is determined by which /dev/md* was
 	 * openned
@@ -4788,6 +5072,17 @@ static int set_array_info(mddev_t * mddev, mdu_array_info_t *info)
 	return 0;
 }
 
+void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors)
+{
+	WARN(!mddev_is_locked(mddev), "%s: unlocked mddev!\n", __func__);
+
+	if (mddev->external_size)
+		return;
+
+	mddev->array_sectors = array_sectors;
+}
+EXPORT_SYMBOL(md_set_array_sectors);
+
 static int update_size(mddev_t *mddev, sector_t num_sectors)
 {
 	mdk_rdev_t *rdev;
@@ -4814,8 +5109,7 @@ static int update_size(mddev_t *mddev, sector_t num_sectors)
 		 */
 		return -EBUSY;
 	list_for_each_entry(rdev, &mddev->disks, same_set) {
-		sector_t avail;
-		avail = rdev->size * 2;
+		sector_t avail = rdev->sectors;
 
 		if (fit && (num_sectors == 0 || num_sectors > avail))
 			num_sectors = avail;
@@ -4887,12 +5181,18 @@ static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
 		)
 		return -EINVAL;
 	/* Check there is only one change */
-	if (info->size >= 0 && mddev->size != info->size) cnt++;
-	if (mddev->raid_disks != info->raid_disks) cnt++;
-	if (mddev->layout != info->layout) cnt++;
-	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) cnt++;
-	if (cnt == 0) return 0;
-	if (cnt > 1) return -EINVAL;
+	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
+		cnt++;
+	if (mddev->raid_disks != info->raid_disks)
+		cnt++;
+	if (mddev->layout != info->layout)
+		cnt++;
+	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT))
+		cnt++;
+	if (cnt == 0)
+		return 0;
+	if (cnt > 1)
+		return -EINVAL;
 
 	if (mddev->layout != info->layout) {
 		/* Change layout
@@ -4904,7 +5204,7 @@ static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
 		else
 			return mddev->pers->reconfig(mddev, info->layout, -1);
 	}
-	if (info->size >= 0 && mddev->size != info->size)
+	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
 		rv = update_size(mddev, (sector_t)info->size * 2);
 
 	if (mddev->raid_disks    != info->raid_disks)
@@ -5331,6 +5631,8 @@ mdk_thread_t *md_register_thread(void (*run) (mddev_t *), mddev_t *mddev,
 
 void md_unregister_thread(mdk_thread_t *thread)
 {
+	if (!thread)
+		return;
 	dprintk("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
 
 	kthread_stop(thread->tsk);
@@ -5404,7 +5706,7 @@ static void status_resync(struct seq_file *seq, mddev_t * mddev)
 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
 		max_blocks = mddev->resync_max_sectors >> 1;
 	else
-		max_blocks = mddev->size;
+		max_blocks = mddev->dev_sectors / 2;
 
 	/*
 	 * Should not happen.
@@ -5537,7 +5839,7 @@ struct mdstat_info {
 static int md_seq_show(struct seq_file *seq, void *v)
 {
 	mddev_t *mddev = v;
-	sector_t size;
+	sector_t sectors;
 	mdk_rdev_t *rdev;
 	struct mdstat_info *mi = seq->private;
 	struct bitmap *bitmap;
@@ -5573,7 +5875,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
 			seq_printf(seq, " %s", mddev->pers->name);
 		}
 
-		size = 0;
+		sectors = 0;
 		list_for_each_entry(rdev, &mddev->disks, same_set) {
 			char b[BDEVNAME_SIZE];
 			seq_printf(seq, " %s[%d]",
@@ -5585,7 +5887,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
 				continue;
 			} else if (rdev->raid_disk < 0)
 				seq_printf(seq, "(S)"); /* spare */
-			size += rdev->size;
+			sectors += rdev->sectors;
 		}
 
 		if (!list_empty(&mddev->disks)) {
@@ -5595,7 +5897,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
 					   mddev->array_sectors / 2);
 			else
 				seq_printf(seq, "\n      %llu blocks",
-					   (unsigned long long)size);
+					   (unsigned long long)sectors / 2);
 		}
 		if (mddev->persistent) {
 			if (mddev->major_version != 0 ||
@@ -5722,19 +6024,19 @@ int unregister_md_personality(struct mdk_personality *p)
 	return 0;
 }
 
-static int is_mddev_idle(mddev_t *mddev)
+static int is_mddev_idle(mddev_t *mddev, int init)
 {
 	mdk_rdev_t * rdev;
 	int idle;
-	long curr_events;
+	int curr_events;
 
 	idle = 1;
 	rcu_read_lock();
 	rdev_for_each_rcu(rdev, mddev) {
 		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
-		curr_events = part_stat_read(&disk->part0, sectors[0]) +
-				part_stat_read(&disk->part0, sectors[1]) -
-				atomic_read(&disk->sync_io);
+		curr_events = (int)part_stat_read(&disk->part0, sectors[0]) +
+			      (int)part_stat_read(&disk->part0, sectors[1]) -
+			      atomic_read(&disk->sync_io);
 		/* sync IO will cause sync_io to increase before the disk_stats
 		 * as sync_io is counted when a request starts, and
 		 * disk_stats is counted when it completes.
@@ -5757,7 +6059,7 @@ static int is_mddev_idle(mddev_t *mddev)
 		 * always make curr_events less than last_events.
 		 *
 		 */
-		if (curr_events - rdev->last_events > 4096) {
+		if (init || curr_events - rdev->last_events > 64) {
 			rdev->last_events = curr_events;
 			idle = 0;
 		}
@@ -5980,10 +6282,10 @@ void md_do_sync(mddev_t *mddev)
 			j = mddev->recovery_cp;
 
 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
-		max_sectors = mddev->size << 1;
+		max_sectors = mddev->dev_sectors;
 	else {
 		/* recovery follows the physical size of devices */
-		max_sectors = mddev->size << 1;
+		max_sectors = mddev->dev_sectors;
 		j = MaxSector;
 		list_for_each_entry(rdev, &mddev->disks, same_set)
 			if (rdev->raid_disk >= 0 &&
@@ -6000,7 +6302,7 @@ void md_do_sync(mddev_t *mddev)
 	       "(but not more than %d KB/sec) for %s.\n",
 	       speed_max(mddev), desc);
 
-	is_mddev_idle(mddev); /* this also initializes IO event counters */
+	is_mddev_idle(mddev, 1); /* this initializes IO event counters */
 
 	io_sectors = 0;
 	for (m = 0; m < SYNC_MARKS; m++) {
@@ -6040,6 +6342,18 @@ void md_do_sync(mddev_t *mddev)
 		}
 		if (kthread_should_stop())
 			goto interrupted;
+
+		if (mddev->curr_resync > mddev->curr_resync_completed &&
+		    (mddev->curr_resync - mddev->curr_resync_completed)
+		    > (max_sectors >> 4)) {
+			/* time to update curr_resync_completed */
+			blk_unplug(mddev->queue);
+			wait_event(mddev->recovery_wait,
+				   atomic_read(&mddev->recovery_active) == 0);
+			mddev->curr_resync_completed =
+				mddev->curr_resync;
+			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
+		}
 		sectors = mddev->pers->sync_request(mddev, j, &skipped,
 						  currspeed < speed_min(mddev));
 		if (sectors == 0) {
@@ -6102,7 +6416,7 @@ void md_do_sync(mddev_t *mddev)
 
 		if (currspeed > speed_min(mddev)) {
 			if ((currspeed > speed_max(mddev)) ||
-					!is_mddev_idle(mddev)) {
+					!is_mddev_idle(mddev, 0)) {
 				msleep(500);
 				goto repeat;
 			}
@@ -6173,6 +6487,8 @@ static int remove_and_add_spares(mddev_t *mddev)
 	mdk_rdev_t *rdev;
 	int spares = 0;
 
+	mddev->curr_resync_completed = 0;
+
 	list_for_each_entry(rdev, &mddev->disks, same_set)
 		if (rdev->raid_disk >= 0 &&
 		    !test_bit(Blocked, &rdev->flags) &&
@@ -6327,6 +6643,9 @@ void md_check_recovery(mddev_t *mddev)
 					sysfs_notify(&mddev->kobj, NULL,
 						     "degraded");
 			}
+			if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
+			    mddev->pers->finish_reshape)
+				mddev->pers->finish_reshape(mddev);
 			md_update_sb(mddev, 1);
 
 			/* if array is no-longer degraded, then any saved_raid_disk
@@ -6470,13 +6789,13 @@ static void md_geninit(void)
 
 static int __init md_init(void)
 {
-	if (register_blkdev(MAJOR_NR, "md"))
+	if (register_blkdev(MD_MAJOR, "md"))
 		return -1;
 	if ((mdp_major=register_blkdev(0, "mdp"))<=0) {
-		unregister_blkdev(MAJOR_NR, "md");
+		unregister_blkdev(MD_MAJOR, "md");
 		return -1;
 	}
-	blk_register_region(MKDEV(MAJOR_NR, 0), 1UL<<MINORBITS, THIS_MODULE,
+	blk_register_region(MKDEV(MD_MAJOR, 0), 1UL<<MINORBITS, THIS_MODULE,
 			    md_probe, NULL, NULL);
 	blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
 			    md_probe, NULL, NULL);
@@ -6562,10 +6881,10 @@ static __exit void md_exit(void)
 	mddev_t *mddev;
 	struct list_head *tmp;
 
-	blk_unregister_region(MKDEV(MAJOR_NR,0), 1U << MINORBITS);
+	blk_unregister_region(MKDEV(MD_MAJOR,0), 1U << MINORBITS);
 	blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
 
-	unregister_blkdev(MAJOR_NR,"md");
+	unregister_blkdev(MD_MAJOR,"md");
 	unregister_blkdev(mdp_major, "mdp");
 	unregister_reboot_notifier(&md_notifier);
 	unregister_sysctl_table(raid_table_header);
diff --git a/drivers/md/md.h b/drivers/md/md.h
new file mode 100644
index 0000000..e9b7f54
--- /dev/null
+++ b/drivers/md/md.h
@@ -0,0 +1,436 @@
+/*
+   md_k.h : kernel internal structure of the Linux MD driver
+          Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
+	  
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+   
+   You should have received a copy of the GNU General Public License
+   (for example /usr/src/linux/COPYING); if not, write to the Free
+   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  
+*/
+
+#ifndef _MD_K_H
+#define _MD_K_H
+
+#ifdef CONFIG_BLOCK
+
+#define MaxSector (~(sector_t)0)
+
+typedef struct mddev_s mddev_t;
+typedef struct mdk_rdev_s mdk_rdev_t;
+
+/*
+ * options passed in raidrun:
+ */
+
+/* Currently this must fit in an 'int' */
+#define MAX_CHUNK_SIZE (1<<30)
+
+/*
+ * MD's 'extended' device
+ */
+struct mdk_rdev_s
+{
+	struct list_head same_set;	/* RAID devices within the same set */
+
+	sector_t sectors;		/* Device size (in 512bytes sectors) */
+	mddev_t *mddev;			/* RAID array if running */
+	int last_events;		/* IO event timestamp */
+
+	struct block_device *bdev;	/* block device handle */
+
+	struct page	*sb_page;
+	int		sb_loaded;
+	__u64		sb_events;
+	sector_t	data_offset;	/* start of data in array */
+	sector_t 	sb_start;	/* offset of the super block (in 512byte sectors) */
+	int		sb_size;	/* bytes in the superblock */
+	int		preferred_minor;	/* autorun support */
+
+	struct kobject	kobj;
+
+	/* A device can be in one of three states based on two flags:
+	 * Not working:   faulty==1 in_sync==0
+	 * Fully working: faulty==0 in_sync==1
+	 * Working, but not
+	 * in sync with array
+	 *                faulty==0 in_sync==0
+	 *
+	 * It can never have faulty==1, in_sync==1
+	 * This reduces the burden of testing multiple flags in many cases
+	 */
+
+	unsigned long	flags;
+#define	Faulty		1		/* device is known to have a fault */
+#define	In_sync		2		/* device is in_sync with rest of array */
+#define	WriteMostly	4		/* Avoid reading if at all possible */
+#define	BarriersNotsupp	5		/* BIO_RW_BARRIER is not supported */
+#define	AllReserved	6		/* If whole device is reserved for
+					 * one array */
+#define	AutoDetected	7		/* added by auto-detect */
+#define Blocked		8		/* An error occured on an externally
+					 * managed array, don't allow writes
+					 * until it is cleared */
+#define StateChanged	9		/* Faulty or Blocked has changed during
+					 * interrupt, so it needs to be
+					 * notified by the thread */
+	wait_queue_head_t blocked_wait;
+
+	int desc_nr;			/* descriptor index in the superblock */
+	int raid_disk;			/* role of device in array */
+	int saved_raid_disk;		/* role that device used to have in the
+					 * array and could again if we did a partial
+					 * resync from the bitmap
+					 */
+	sector_t	recovery_offset;/* If this device has been partially
+					 * recovered, this is where we were
+					 * up to.
+					 */
+
+	atomic_t	nr_pending;	/* number of pending requests.
+					 * only maintained for arrays that
+					 * support hot removal
+					 */
+	atomic_t	read_errors;	/* number of consecutive read errors that
+					 * we have tried to ignore.
+					 */
+	atomic_t	corrected_errors; /* number of corrected read errors,
+					   * for reporting to userspace and storing
+					   * in superblock.
+					   */
+	struct work_struct del_work;	/* used for delayed sysfs removal */
+
+	struct sysfs_dirent *sysfs_state; /* handle for 'state'
+					   * sysfs entry */
+};
+
+struct mddev_s
+{
+	void				*private;
+	struct mdk_personality		*pers;
+	dev_t				unit;
+	int				md_minor;
+	struct list_head 		disks;
+	unsigned long			flags;
+#define MD_CHANGE_DEVS	0	/* Some device status has changed */
+#define MD_CHANGE_CLEAN 1	/* transition to or from 'clean' */
+#define MD_CHANGE_PENDING 2	/* superblock update in progress */
+
+	int				suspended;
+	atomic_t			active_io;
+	int				ro;
+
+	struct gendisk			*gendisk;
+
+	struct kobject			kobj;
+	int				hold_active;
+#define	UNTIL_IOCTL	1
+#define	UNTIL_STOP	2
+
+	/* Superblock information */
+	int				major_version,
+					minor_version,
+					patch_version;
+	int				persistent;
+	int 				external;	/* metadata is
+							 * managed externally */
+	char				metadata_type[17]; /* externally set*/
+	int				chunk_size;
+	time_t				ctime, utime;
+	int				level, layout;
+	char				clevel[16];
+	int				raid_disks;
+	int				max_disks;
+	sector_t			dev_sectors; 	/* used size of
+							 * component devices */
+	sector_t			array_sectors; /* exported array size */
+	int				external_size; /* size managed
+							* externally */
+	__u64				events;
+
+	char				uuid[16];
+
+	/* If the array is being reshaped, we need to record the
+	 * new shape and an indication of where we are up to.
+	 * This is written to the superblock.
+	 * If reshape_position is MaxSector, then no reshape is happening (yet).
+	 */
+	sector_t			reshape_position;
+	int				delta_disks, new_level, new_layout, new_chunk;
+
+	struct mdk_thread_s		*thread;	/* management thread */
+	struct mdk_thread_s		*sync_thread;	/* doing resync or reconstruct */
+	sector_t			curr_resync;	/* last block scheduled */
+	/* As resync requests can complete out of order, we cannot easily track
+	 * how much resync has been completed.  So we occasionally pause until
+	 * everything completes, then set curr_resync_completed to curr_resync.
+	 * As such it may be well behind the real resync mark, but it is a value
+	 * we are certain of.
+	 */
+	sector_t			curr_resync_completed;
+	unsigned long			resync_mark;	/* a recent timestamp */
+	sector_t			resync_mark_cnt;/* blocks written at resync_mark */
+	sector_t			curr_mark_cnt; /* blocks scheduled now */
+
+	sector_t			resync_max_sectors; /* may be set by personality */
+
+	sector_t			resync_mismatches; /* count of sectors where
+							    * parity/replica mismatch found
+							    */
+
+	/* allow user-space to request suspension of IO to regions of the array */
+	sector_t			suspend_lo;
+	sector_t			suspend_hi;
+	/* if zero, use the system-wide default */
+	int				sync_speed_min;
+	int				sync_speed_max;
+
+	/* resync even though the same disks are shared among md-devices */
+	int				parallel_resync;
+
+	int				ok_start_degraded;
+	/* recovery/resync flags 
+	 * NEEDED:   we might need to start a resync/recover
+	 * RUNNING:  a thread is running, or about to be started
+	 * SYNC:     actually doing a resync, not a recovery
+	 * RECOVER:  doing recovery, or need to try it.
+	 * INTR:     resync needs to be aborted for some reason
+	 * DONE:     thread is done and is waiting to be reaped
+	 * REQUEST:  user-space has requested a sync (used with SYNC)
+	 * CHECK:    user-space request for for check-only, no repair
+	 * RESHAPE:  A reshape is happening
+	 *
+	 * If neither SYNC or RESHAPE are set, then it is a recovery.
+	 */
+#define	MD_RECOVERY_RUNNING	0
+#define	MD_RECOVERY_SYNC	1
+#define	MD_RECOVERY_RECOVER	2
+#define	MD_RECOVERY_INTR	3
+#define	MD_RECOVERY_DONE	4
+#define	MD_RECOVERY_NEEDED	5
+#define	MD_RECOVERY_REQUESTED	6
+#define	MD_RECOVERY_CHECK	7
+#define MD_RECOVERY_RESHAPE	8
+#define	MD_RECOVERY_FROZEN	9
+
+	unsigned long			recovery;
+	int				recovery_disabled; /* if we detect that recovery
+							    * will always fail, set this
+							    * so we don't loop trying */
+
+	int				in_sync;	/* know to not need resync */
+	struct mutex			reconfig_mutex;
+	atomic_t			active;		/* general refcount */
+	atomic_t			openers;	/* number of active opens */
+
+	int				changed;	/* true if we might need to reread partition info */
+	int				degraded;	/* whether md should consider
+							 * adding a spare
+							 */
+	int				barriers_work;	/* initialised to true, cleared as soon
+							 * as a barrier request to slave
+							 * fails.  Only supported
+							 */
+	struct bio			*biolist; 	/* bios that need to be retried
+							 * because BIO_RW_BARRIER is not supported
+							 */
+
+	atomic_t			recovery_active; /* blocks scheduled, but not written */
+	wait_queue_head_t		recovery_wait;
+	sector_t			recovery_cp;
+	sector_t			resync_min;	/* user requested sync
+							 * starts here */
+	sector_t			resync_max;	/* resync should pause
+							 * when it gets here */
+
+	struct sysfs_dirent		*sysfs_state;	/* handle for 'array_state'
+							 * file in sysfs.
+							 */
+	struct sysfs_dirent		*sysfs_action;  /* handle for 'sync_action' */
+
+	struct work_struct del_work;	/* used for delayed sysfs removal */
+
+	spinlock_t			write_lock;
+	wait_queue_head_t		sb_wait;	/* for waiting on superblock updates */
+	atomic_t			pending_writes;	/* number of active superblock writes */
+
+	unsigned int			safemode;	/* if set, update "clean" superblock
+							 * when no writes pending.
+							 */ 
+	unsigned int			safemode_delay;
+	struct timer_list		safemode_timer;
+	atomic_t			writes_pending; 
+	struct request_queue		*queue;	/* for plugging ... */
+
+	atomic_t                        write_behind; /* outstanding async IO */
+	unsigned int                    max_write_behind; /* 0 = sync */
+
+	struct bitmap                   *bitmap; /* the bitmap for the device */
+	struct file			*bitmap_file; /* the bitmap file */
+	long				bitmap_offset; /* offset from superblock of
+							* start of bitmap. May be
+							* negative, but not '0'
+							*/
+	long				default_bitmap_offset; /* this is the offset to use when
+								* hot-adding a bitmap.  It should
+								* eventually be settable by sysfs.
+								*/
+
+	struct list_head		all_mddevs;
+};
+
+
+static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
+{
+	int faulty = test_bit(Faulty, &rdev->flags);
+	if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
+		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+}
+
+static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
+{
+        atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
+}
+
+struct mdk_personality
+{
+	char *name;
+	int level;
+	struct list_head list;
+	struct module *owner;
+	int (*make_request)(struct request_queue *q, struct bio *bio);
+	int (*run)(mddev_t *mddev);
+	int (*stop)(mddev_t *mddev);
+	void (*status)(struct seq_file *seq, mddev_t *mddev);
+	/* error_handler must set ->faulty and clear ->in_sync
+	 * if appropriate, and should abort recovery if needed 
+	 */
+	void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
+	int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
+	int (*hot_remove_disk) (mddev_t *mddev, int number);
+	int (*spare_active) (mddev_t *mddev);
+	sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
+	int (*resize) (mddev_t *mddev, sector_t sectors);
+	sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks);
+	int (*check_reshape) (mddev_t *mddev);
+	int (*start_reshape) (mddev_t *mddev);
+	void (*finish_reshape) (mddev_t *mddev);
+	int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
+	/* quiesce moves between quiescence states
+	 * 0 - fully active
+	 * 1 - no new requests allowed
+	 * others - reserved
+	 */
+	void (*quiesce) (mddev_t *mddev, int state);
+	/* takeover is used to transition an array from one
+	 * personality to another.  The new personality must be able
+	 * to handle the data in the current layout.
+	 * e.g. 2drive raid1 -> 2drive raid5
+	 *      ndrive raid5 -> degraded n+1drive raid6 with special layout
+	 * If the takeover succeeds, a new 'private' structure is returned.
+	 * This needs to be installed and then ->run used to activate the
+	 * array.
+	 */
+	void *(*takeover) (mddev_t *mddev);
+};
+
+
+struct md_sysfs_entry {
+	struct attribute attr;
+	ssize_t (*show)(mddev_t *, char *);
+	ssize_t (*store)(mddev_t *, const char *, size_t);
+};
+
+
+static inline char * mdname (mddev_t * mddev)
+{
+	return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
+}
+
+/*
+ * iterates through some rdev ringlist. It's safe to remove the
+ * current 'rdev'. Dont touch 'tmp' though.
+ */
+#define rdev_for_each_list(rdev, tmp, head)				\
+	list_for_each_entry_safe(rdev, tmp, head, same_set)
+
+/*
+ * iterates through the 'same array disks' ringlist
+ */
+#define rdev_for_each(rdev, tmp, mddev)				\
+	list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
+
+#define rdev_for_each_rcu(rdev, mddev)				\
+	list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
+
+typedef struct mdk_thread_s {
+	void			(*run) (mddev_t *mddev);
+	mddev_t			*mddev;
+	wait_queue_head_t	wqueue;
+	unsigned long           flags;
+	struct task_struct	*tsk;
+	unsigned long		timeout;
+} mdk_thread_t;
+
+#define THREAD_WAKEUP  0
+
+#define __wait_event_lock_irq(wq, condition, lock, cmd) 		\
+do {									\
+	wait_queue_t __wait;						\
+	init_waitqueue_entry(&__wait, current);				\
+									\
+	add_wait_queue(&wq, &__wait);					\
+	for (;;) {							\
+		set_current_state(TASK_UNINTERRUPTIBLE);		\
+		if (condition)						\
+			break;						\
+		spin_unlock_irq(&lock);					\
+		cmd;							\
+		schedule();						\
+		spin_lock_irq(&lock);					\
+	}								\
+	current->state = TASK_RUNNING;					\
+	remove_wait_queue(&wq, &__wait);				\
+} while (0)
+
+#define wait_event_lock_irq(wq, condition, lock, cmd) 			\
+do {									\
+	if (condition)	 						\
+		break;							\
+	__wait_event_lock_irq(wq, condition, lock, cmd);		\
+} while (0)
+
+static inline void safe_put_page(struct page *p)
+{
+	if (p) put_page(p);
+}
+
+#endif /* CONFIG_BLOCK */
+#endif
+
+
+extern int register_md_personality(struct mdk_personality *p);
+extern int unregister_md_personality(struct mdk_personality *p);
+extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
+				mddev_t *mddev, const char *name);
+extern void md_unregister_thread(mdk_thread_t *thread);
+extern void md_wakeup_thread(mdk_thread_t *thread);
+extern void md_check_recovery(mddev_t *mddev);
+extern void md_write_start(mddev_t *mddev, struct bio *bi);
+extern void md_write_end(mddev_t *mddev);
+extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
+extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
+
+extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
+			   sector_t sector, int size, struct page *page);
+extern void md_super_wait(mddev_t *mddev);
+extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
+			struct page *page, int rw);
+extern void md_do_sync(mddev_t *mddev);
+extern void md_new_event(mddev_t *mddev);
+extern int md_allow_write(mddev_t *mddev);
+extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
+extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
diff --git a/drivers/md/mktables.c b/drivers/md/mktables.c
index b61d576..3b15008 100644
--- a/drivers/md/mktables.c
+++ b/drivers/md/mktables.c
@@ -59,7 +59,7 @@ int main(int argc, char *argv[])
 	uint8_t v;
 	uint8_t exptbl[256], invtbl[256];
 
-	printf("#include \"raid6.h\"\n");
+	printf("#include <linux/raid/pq.h>\n");
 
 	/* Compute multiplication table */
 	printf("\nconst u8  __attribute__((aligned(256)))\n"
@@ -76,6 +76,9 @@ int main(int argc, char *argv[])
 		printf("\t},\n");
 	}
 	printf("};\n");
+	printf("#ifdef __KERNEL__\n");
+	printf("EXPORT_SYMBOL(raid6_gfmul);\n");
+	printf("#endif\n");
 
 	/* Compute power-of-2 table (exponent) */
 	v = 1;
@@ -92,6 +95,9 @@ int main(int argc, char *argv[])
 		}
 	}
 	printf("};\n");
+	printf("#ifdef __KERNEL__\n");
+	printf("EXPORT_SYMBOL(raid6_gfexp);\n");
+	printf("#endif\n");
 
 	/* Compute inverse table x^-1 == x^254 */
 	printf("\nconst u8 __attribute__((aligned(256)))\n"
@@ -104,6 +110,9 @@ int main(int argc, char *argv[])
 		}
 	}
 	printf("};\n");
+	printf("#ifdef __KERNEL__\n");
+	printf("EXPORT_SYMBOL(raid6_gfinv);\n");
+	printf("#endif\n");
 
 	/* Compute inv(2^x + 1) (exponent-xor-inverse) table */
 	printf("\nconst u8 __attribute__((aligned(256)))\n"
@@ -115,6 +124,9 @@ int main(int argc, char *argv[])
 			       (j == 7) ? '\n' : ' ');
 	}
 	printf("};\n");
+	printf("#ifdef __KERNEL__\n");
+	printf("EXPORT_SYMBOL(raid6_gfexi);\n");
+	printf("#endif\n");
 
 	return 0;
 }
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index f6d08f2..41ced0c 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -19,7 +19,11 @@
  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include <linux/raid/multipath.h>
+#include <linux/blkdev.h>
+#include <linux/raid/md_u.h>
+#include <linux/seq_file.h>
+#include "md.h"
+#include "multipath.h"
 
 #define MAX_WORK_PER_DISK 128
 
@@ -402,6 +406,14 @@ static void multipathd (mddev_t *mddev)
 	spin_unlock_irqrestore(&conf->device_lock, flags);
 }
 
+static sector_t multipath_size(mddev_t *mddev, sector_t sectors, int raid_disks)
+{
+	WARN_ONCE(sectors || raid_disks,
+		  "%s does not support generic reshape\n", __func__);
+
+	return mddev->dev_sectors;
+}
+
 static int multipath_run (mddev_t *mddev)
 {
 	multipath_conf_t *conf;
@@ -498,7 +510,7 @@ static int multipath_run (mddev_t *mddev)
 	/*
 	 * Ok, everything is just fine now
 	 */
-	mddev->array_sectors = mddev->size * 2;
+	md_set_array_sectors(mddev, multipath_size(mddev, 0, 0));
 
 	mddev->queue->unplug_fn = multipath_unplug;
 	mddev->queue->backing_dev_info.congested_fn = multipath_congested;
@@ -543,6 +555,7 @@ static struct mdk_personality multipath_personality =
 	.error_handler	= multipath_error,
 	.hot_add_disk	= multipath_add_disk,
 	.hot_remove_disk= multipath_remove_disk,
+	.size		= multipath_size,
 };
 
 static int __init multipath_init (void)
diff --git a/drivers/md/multipath.h b/drivers/md/multipath.h
new file mode 100644
index 0000000..6fa70b4
--- /dev/null
+++ b/drivers/md/multipath.h
@@ -0,0 +1,40 @@
+#ifndef _MULTIPATH_H
+#define _MULTIPATH_H
+
+struct multipath_info {
+	mdk_rdev_t	*rdev;
+};
+
+struct multipath_private_data {
+	mddev_t			*mddev;
+	struct multipath_info	*multipaths;
+	int			raid_disks;
+	int			working_disks;
+	spinlock_t		device_lock;
+	struct list_head	retry_list;
+
+	mempool_t		*pool;
+};
+
+typedef struct multipath_private_data multipath_conf_t;
+
+/*
+ * this is the only point in the RAID code where we violate
+ * C type safety. mddev->private is an 'opaque' pointer.
+ */
+#define mddev_to_conf(mddev) ((multipath_conf_t *) mddev->private)
+
+/*
+ * this is our 'private' 'collective' MULTIPATH buffer head.
+ * it contains information about what kind of IO operations were started
+ * for this MULTIPATH operation, and about their status:
+ */
+
+struct multipath_bh {
+	mddev_t			*mddev;
+	struct bio		*master_bio;
+	struct bio		bio;
+	int			path;
+	struct list_head	retry_list;
+};
+#endif
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index c605ba8..c08d755 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -18,7 +18,10 @@
    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  
 */
 
-#include <linux/raid/raid0.h>
+#include <linux/blkdev.h>
+#include <linux/seq_file.h>
+#include "md.h"
+#include "raid0.h"
 
 static void raid0_unplug(struct request_queue *q)
 {
@@ -73,16 +76,15 @@ static int create_strip_zones (mddev_t *mddev)
 		list_for_each_entry(rdev2, &mddev->disks, same_set) {
 			printk(KERN_INFO "raid0:   comparing %s(%llu)",
 			       bdevname(rdev1->bdev,b),
-			       (unsigned long long)rdev1->size);
+			       (unsigned long long)rdev1->sectors);
 			printk(KERN_INFO " with %s(%llu)\n",
 			       bdevname(rdev2->bdev,b),
-			       (unsigned long long)rdev2->size);
+			       (unsigned long long)rdev2->sectors);
 			if (rdev2 == rdev1) {
 				printk(KERN_INFO "raid0:   END\n");
 				break;
 			}
-			if (rdev2->size == rdev1->size)
-			{
+			if (rdev2->sectors == rdev1->sectors) {
 				/*
 				 * Not unique, don't count it as a new
 				 * group
@@ -145,7 +147,7 @@ static int create_strip_zones (mddev_t *mddev)
 		    mddev->queue->max_sectors > (PAGE_SIZE>>9))
 			blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
 
-		if (!smallest || (rdev1->size <smallest->size))
+		if (!smallest || (rdev1->sectors < smallest->sectors))
 			smallest = rdev1;
 		cnt++;
 	}
@@ -155,10 +157,10 @@ static int create_strip_zones (mddev_t *mddev)
 		goto abort;
 	}
 	zone->nb_dev = cnt;
-	zone->sectors = smallest->size * cnt * 2;
+	zone->sectors = smallest->sectors * cnt;
 	zone->zone_start = 0;
 
-	current_start = smallest->size * 2;
+	current_start = smallest->sectors;
 	curr_zone_start = zone->sectors;
 
 	/* now do the other zones */
@@ -177,29 +179,29 @@ static int create_strip_zones (mddev_t *mddev)
 			rdev = conf->strip_zone[0].dev[j];
 			printk(KERN_INFO "raid0: checking %s ...",
 				bdevname(rdev->bdev, b));
-			if (rdev->size > current_start / 2) {
-				printk(KERN_INFO " contained as device %d\n",
-					c);
-				zone->dev[c] = rdev;
-				c++;
-				if (!smallest || (rdev->size <smallest->size)) {
-					smallest = rdev;
-					printk(KERN_INFO "  (%llu) is smallest!.\n",
-						(unsigned long long)rdev->size);
-				}
-			} else
+			if (rdev->sectors <= current_start) {
 				printk(KERN_INFO " nope.\n");
+				continue;
+			}
+			printk(KERN_INFO " contained as device %d\n", c);
+			zone->dev[c] = rdev;
+			c++;
+			if (!smallest || rdev->sectors < smallest->sectors) {
+				smallest = rdev;
+				printk(KERN_INFO "  (%llu) is smallest!.\n",
+					(unsigned long long)rdev->sectors);
+			}
 		}
 
 		zone->nb_dev = c;
-		zone->sectors = (smallest->size * 2 - current_start) * c;
+		zone->sectors = (smallest->sectors - current_start) * c;
 		printk(KERN_INFO "raid0: zone->nb_dev: %d, sectors: %llu\n",
 			zone->nb_dev, (unsigned long long)zone->sectors);
 
 		zone->zone_start = curr_zone_start;
 		curr_zone_start += zone->sectors;
 
-		current_start = smallest->size * 2;
+		current_start = smallest->sectors;
 		printk(KERN_INFO "raid0: current zone start: %llu\n",
 			(unsigned long long)current_start);
 	}
@@ -261,12 +263,25 @@ static int raid0_mergeable_bvec(struct request_queue *q,
 		return max;
 }
 
+static sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks)
+{
+	sector_t array_sectors = 0;
+	mdk_rdev_t *rdev;
+
+	WARN_ONCE(sectors || raid_disks,
+		  "%s does not support generic reshape\n", __func__);
+
+	list_for_each_entry(rdev, &mddev->disks, same_set)
+		array_sectors += rdev->sectors;
+
+	return array_sectors;
+}
+
 static int raid0_run (mddev_t *mddev)
 {
 	unsigned  cur=0, i=0, nb_zone;
 	s64 sectors;
 	raid0_conf_t *conf;
-	mdk_rdev_t *rdev;
 
 	if (mddev->chunk_size == 0) {
 		printk(KERN_ERR "md/raid0: non-zero chunk size required.\n");
@@ -291,16 +306,14 @@ static int raid0_run (mddev_t *mddev)
 		goto out_free_conf;
 
 	/* calculate array device size */
-	mddev->array_sectors = 0;
-	list_for_each_entry(rdev, &mddev->disks, same_set)
-		mddev->array_sectors += rdev->size * 2;
+	md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
 
 	printk(KERN_INFO "raid0 : md_size is %llu sectors.\n",
 		(unsigned long long)mddev->array_sectors);
 	printk(KERN_INFO "raid0 : conf->spacing is %llu sectors.\n",
 		(unsigned long long)conf->spacing);
 	{
-		sector_t s = mddev->array_sectors;
+		sector_t s = raid0_size(mddev, 0, 0);
 		sector_t space = conf->spacing;
 		int round;
 		conf->sector_shift = 0;
@@ -509,6 +522,7 @@ static struct mdk_personality raid0_personality=
 	.run		= raid0_run,
 	.stop		= raid0_stop,
 	.status		= raid0_status,
+	.size		= raid0_size,
 };
 
 static int __init raid0_init (void)
diff --git a/drivers/md/raid0.h b/drivers/md/raid0.h
new file mode 100644
index 0000000..824b12e
--- /dev/null
+++ b/drivers/md/raid0.h
@@ -0,0 +1,28 @@
+#ifndef _RAID0_H
+#define _RAID0_H
+
+struct strip_zone
+{
+	sector_t zone_start;	/* Zone offset in md_dev (in sectors) */
+	sector_t dev_start;	/* Zone offset in real dev (in sectors) */
+	sector_t sectors;	/* Zone size in sectors */
+	int nb_dev;		/* # of devices attached to the zone */
+	mdk_rdev_t **dev;	/* Devices attached to the zone */
+};
+
+struct raid0_private_data
+{
+	struct strip_zone **hash_table; /* Table of indexes into strip_zone */
+	struct strip_zone *strip_zone;
+	mdk_rdev_t **devlist; /* lists of rdevs, pointed to by strip_zone->dev */
+	int nr_strip_zones;
+
+	sector_t spacing;
+	int sector_shift; /* shift this before divide by spacing */
+};
+
+typedef struct raid0_private_data raid0_conf_t;
+
+#define mddev_to_conf(mddev) ((raid0_conf_t *) mddev->private)
+
+#endif
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index e246642..b4f4bad 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -31,10 +31,13 @@
  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include "dm-bio-list.h"
 #include <linux/delay.h>
-#include <linux/raid/raid1.h>
-#include <linux/raid/bitmap.h>
+#include <linux/blkdev.h>
+#include <linux/seq_file.h>
+#include "md.h"
+#include "dm-bio-list.h"
+#include "raid1.h"
+#include "bitmap.h"
 
 #define DEBUG 0
 #if DEBUG
@@ -1723,7 +1726,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
 			return 0;
 	}
 
-	max_sector = mddev->size << 1;
+	max_sector = mddev->dev_sectors;
 	if (sector_nr >= max_sector) {
 		/* If we aborted, we need to abort the
 		 * sync on the 'current' bitmap chunk (there will
@@ -1919,6 +1922,14 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
 	return nr_sectors;
 }
 
+static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
+{
+	if (sectors)
+		return sectors;
+
+	return mddev->dev_sectors;
+}
+
 static int run(mddev_t *mddev)
 {
 	conf_t *conf;
@@ -2048,7 +2059,7 @@ static int run(mddev_t *mddev)
 	/*
 	 * Ok, everything is just fine now
 	 */
-	mddev->array_sectors = mddev->size * 2;
+	md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
 
 	mddev->queue->unplug_fn = raid1_unplug;
 	mddev->queue->backing_dev_info.congested_fn = raid1_congested;
@@ -2089,6 +2100,9 @@ static int stop(mddev_t *mddev)
 		/* need to kick something here to make sure I/O goes? */
 	}
 
+	raise_barrier(conf);
+	lower_barrier(conf);
+
 	md_unregister_thread(mddev->thread);
 	mddev->thread = NULL;
 	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
@@ -2110,15 +2124,17 @@ static int raid1_resize(mddev_t *mddev, sector_t sectors)
 	 * any io in the removed space completes, but it hardly seems
 	 * worth it.
 	 */
-	mddev->array_sectors = sectors;
+	md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
+	if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
+		return -EINVAL;
 	set_capacity(mddev->gendisk, mddev->array_sectors);
 	mddev->changed = 1;
-	if (mddev->array_sectors / 2 > mddev->size &&
+	if (sectors > mddev->dev_sectors &&
 	    mddev->recovery_cp == MaxSector) {
-		mddev->recovery_cp = mddev->size << 1;
+		mddev->recovery_cp = mddev->dev_sectors;
 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 	}
-	mddev->size = mddev->array_sectors / 2;
+	mddev->dev_sectors = sectors;
 	mddev->resync_max_sectors = sectors;
 	return 0;
 }
@@ -2264,6 +2280,7 @@ static struct mdk_personality raid1_personality =
 	.spare_active	= raid1_spare_active,
 	.sync_request	= sync_request,
 	.resize		= raid1_resize,
+	.size		= raid1_size,
 	.check_reshape	= raid1_reshape,
 	.quiesce	= raid1_quiesce,
 };
diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
new file mode 100644
index 0000000..1620eea
--- /dev/null
+++ b/drivers/md/raid1.h
@@ -0,0 +1,132 @@
+#ifndef _RAID1_H
+#define _RAID1_H
+
+typedef struct mirror_info mirror_info_t;
+
+struct mirror_info {
+	mdk_rdev_t	*rdev;
+	sector_t	head_position;
+};
+
+/*
+ * memory pools need a pointer to the mddev, so they can force an unplug
+ * when memory is tight, and a count of the number of drives that the
+ * pool was allocated for, so they know how much to allocate and free.
+ * mddev->raid_disks cannot be used, as it can change while a pool is active
+ * These two datums are stored in a kmalloced struct.
+ */
+
+struct pool_info {
+	mddev_t *mddev;
+	int	raid_disks;
+};
+
+
+typedef struct r1bio_s r1bio_t;
+
+struct r1_private_data_s {
+	mddev_t			*mddev;
+	mirror_info_t		*mirrors;
+	int			raid_disks;
+	int			last_used;
+	sector_t		next_seq_sect;
+	spinlock_t		device_lock;
+
+	struct list_head	retry_list;
+	/* queue pending writes and submit them on unplug */
+	struct bio_list		pending_bio_list;
+	/* queue of writes that have been unplugged */
+	struct bio_list		flushing_bio_list;
+
+	/* for use when syncing mirrors: */
+
+	spinlock_t		resync_lock;
+	int			nr_pending;
+	int			nr_waiting;
+	int			nr_queued;
+	int			barrier;
+	sector_t		next_resync;
+	int			fullsync;  /* set to 1 if a full sync is needed,
+					    * (fresh device added).
+					    * Cleared when a sync completes.
+					    */
+
+	wait_queue_head_t	wait_barrier;
+
+	struct pool_info	*poolinfo;
+
+	struct page		*tmppage;
+
+	mempool_t *r1bio_pool;
+	mempool_t *r1buf_pool;
+};
+
+typedef struct r1_private_data_s conf_t;
+
+/*
+ * this is the only point in the RAID code where we violate
+ * C type safety. mddev->private is an 'opaque' pointer.
+ */
+#define mddev_to_conf(mddev) ((conf_t *) mddev->private)
+
+/*
+ * this is our 'private' RAID1 bio.
+ *
+ * it contains information about what kind of IO operations were started
+ * for this RAID1 operation, and about their status:
+ */
+
+struct r1bio_s {
+	atomic_t		remaining; /* 'have we finished' count,
+					    * used from IRQ handlers
+					    */
+	atomic_t		behind_remaining; /* number of write-behind ios remaining
+						 * in this BehindIO request
+						 */
+	sector_t		sector;
+	int			sectors;
+	unsigned long		state;
+	mddev_t			*mddev;
+	/*
+	 * original bio going to /dev/mdx
+	 */
+	struct bio		*master_bio;
+	/*
+	 * if the IO is in READ direction, then this is where we read
+	 */
+	int			read_disk;
+
+	struct list_head	retry_list;
+	struct bitmap_update	*bitmap_update;
+	/*
+	 * if the IO is in WRITE direction, then multiple bios are used.
+	 * We choose the number when they are allocated.
+	 */
+	struct bio		*bios[0];
+	/* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
+};
+
+/* when we get a read error on a read-only array, we redirect to another
+ * device without failing the first device, or trying to over-write to
+ * correct the read error.  To keep track of bad blocks on a per-bio
+ * level, we store IO_BLOCKED in the appropriate 'bios' pointer
+ */
+#define IO_BLOCKED ((struct bio*)1)
+
+/* bits for r1bio.state */
+#define	R1BIO_Uptodate	0
+#define	R1BIO_IsSync	1
+#define	R1BIO_Degraded	2
+#define	R1BIO_BehindIO	3
+#define	R1BIO_Barrier	4
+#define R1BIO_BarrierRetry 5
+/* For write-behind requests, we call bi_end_io when
+ * the last non-write-behind device completes, providing
+ * any write was successful.  Otherwise we call when
+ * any write-behind write succeeds, otherwise we call
+ * with failure when last write completes (and all failed).
+ * Record that bi_end_io was called with this flag...
+ */
+#define	R1BIO_Returned 6
+
+#endif
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 7301631..e293d92 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -18,10 +18,13 @@
  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include "dm-bio-list.h"
 #include <linux/delay.h>
-#include <linux/raid/raid10.h>
-#include <linux/raid/bitmap.h>
+#include <linux/blkdev.h>
+#include <linux/seq_file.h>
+#include "md.h"
+#include "dm-bio-list.h"
+#include "raid10.h"
+#include "bitmap.h"
 
 /*
  * RAID10 provides a combination of RAID0 and RAID1 functionality.
@@ -1695,7 +1698,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
 			return 0;
 
  skipped:
-	max_sector = mddev->size << 1;
+	max_sector = mddev->dev_sectors;
 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
 		max_sector = mddev->resync_max_sectors;
 	if (sector_nr >= max_sector) {
@@ -2020,6 +2023,25 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
 	goto skipped;
 }
 
+static sector_t
+raid10_size(mddev_t *mddev, sector_t sectors, int raid_disks)
+{
+	sector_t size;
+	conf_t *conf = mddev_to_conf(mddev);
+
+	if (!raid_disks)
+		raid_disks = mddev->raid_disks;
+	if (!sectors)
+		sectors = mddev->dev_sectors;
+
+	size = sectors >> conf->chunk_shift;
+	sector_div(size, conf->far_copies);
+	size = size * raid_disks;
+	sector_div(size, conf->near_copies);
+
+	return size << conf->chunk_shift;
+}
+
 static int run(mddev_t *mddev)
 {
 	conf_t *conf;
@@ -2076,7 +2098,7 @@ static int run(mddev_t *mddev)
 	conf->far_offset = fo;
 	conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1;
 	conf->chunk_shift = ffz(~mddev->chunk_size) - 9;
-	size = mddev->size >> (conf->chunk_shift-1);
+	size = mddev->dev_sectors >> conf->chunk_shift;
 	sector_div(size, fc);
 	size = size * conf->raid_disks;
 	sector_div(size, nc);
@@ -2089,7 +2111,7 @@ static int run(mddev_t *mddev)
 	 */
 	stride += conf->raid_disks - 1;
 	sector_div(stride, conf->raid_disks);
-	mddev->size = stride  << (conf->chunk_shift-1);
+	mddev->dev_sectors = stride << conf->chunk_shift;
 
 	if (fo)
 		stride = 1;
@@ -2171,8 +2193,8 @@ static int run(mddev_t *mddev)
 	/*
 	 * Ok, everything is just fine now
 	 */
-	mddev->array_sectors = size << conf->chunk_shift;
-	mddev->resync_max_sectors = size << conf->chunk_shift;
+	md_set_array_sectors(mddev, raid10_size(mddev, 0, 0));
+	mddev->resync_max_sectors = raid10_size(mddev, 0, 0);
 
 	mddev->queue->unplug_fn = raid10_unplug;
 	mddev->queue->backing_dev_info.congested_fn = raid10_congested;
@@ -2208,6 +2230,9 @@ static int stop(mddev_t *mddev)
 {
 	conf_t *conf = mddev_to_conf(mddev);
 
+	raise_barrier(conf, 0);
+	lower_barrier(conf);
+
 	md_unregister_thread(mddev->thread);
 	mddev->thread = NULL;
 	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
@@ -2255,6 +2280,7 @@ static struct mdk_personality raid10_personality =
 	.spare_active	= raid10_spare_active,
 	.sync_request	= sync_request,
 	.quiesce	= raid10_quiesce,
+	.size		= raid10_size,
 };
 
 static int __init raid_init(void)
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
new file mode 100644
index 0000000..244dbe5
--- /dev/null
+++ b/drivers/md/raid10.h
@@ -0,0 +1,121 @@
+#ifndef _RAID10_H
+#define _RAID10_H
+
+typedef struct mirror_info mirror_info_t;
+
+struct mirror_info {
+	mdk_rdev_t	*rdev;
+	sector_t	head_position;
+};
+
+typedef struct r10bio_s r10bio_t;
+
+struct r10_private_data_s {
+	mddev_t			*mddev;
+	mirror_info_t		*mirrors;
+	int			raid_disks;
+	spinlock_t		device_lock;
+
+	/* geometry */
+	int			near_copies;  /* number of copies layed out raid0 style */
+	int 			far_copies;   /* number of copies layed out
+					       * at large strides across drives
+					       */
+	int			far_offset;   /* far_copies are offset by 1 stripe
+					       * instead of many
+					       */
+	int			copies;	      /* near_copies * far_copies.
+					       * must be <= raid_disks
+					       */
+	sector_t		stride;	      /* distance between far copies.
+					       * This is size / far_copies unless
+					       * far_offset, in which case it is
+					       * 1 stripe.
+					       */
+
+	int chunk_shift; /* shift from chunks to sectors */
+	sector_t chunk_mask;
+
+	struct list_head	retry_list;
+	/* queue pending writes and submit them on unplug */
+	struct bio_list		pending_bio_list;
+
+
+	spinlock_t		resync_lock;
+	int nr_pending;
+	int nr_waiting;
+	int nr_queued;
+	int barrier;
+	sector_t		next_resync;
+	int			fullsync;  /* set to 1 if a full sync is needed,
+					    * (fresh device added).
+					    * Cleared when a sync completes.
+					    */
+
+	wait_queue_head_t	wait_barrier;
+
+	mempool_t *r10bio_pool;
+	mempool_t *r10buf_pool;
+	struct page		*tmppage;
+};
+
+typedef struct r10_private_data_s conf_t;
+
+/*
+ * this is the only point in the RAID code where we violate
+ * C type safety. mddev->private is an 'opaque' pointer.
+ */
+#define mddev_to_conf(mddev) ((conf_t *) mddev->private)
+
+/*
+ * this is our 'private' RAID10 bio.
+ *
+ * it contains information about what kind of IO operations were started
+ * for this RAID10 operation, and about their status:
+ */
+
+struct r10bio_s {
+	atomic_t		remaining; /* 'have we finished' count,
+					    * used from IRQ handlers
+					    */
+	sector_t		sector;	/* virtual sector number */
+	int			sectors;
+	unsigned long		state;
+	mddev_t			*mddev;
+	/*
+	 * original bio going to /dev/mdx
+	 */
+	struct bio		*master_bio;
+	/*
+	 * if the IO is in READ direction, then this is where we read
+	 */
+	int			read_slot;
+
+	struct list_head	retry_list;
+	/*
+	 * if the IO is in WRITE direction, then multiple bios are used,
+	 * one for each copy.
+	 * When resyncing we also use one for each copy.
+	 * When reconstructing, we use 2 bios, one for read, one for write.
+	 * We choose the number when they are allocated.
+	 */
+	struct {
+		struct bio		*bio;
+		sector_t addr;
+		int devnum;
+	} devs[0];
+};
+
+/* when we get a read error on a read-only array, we redirect to another
+ * device without failing the first device, or trying to over-write to
+ * correct the read error.  To keep track of bad blocks on a per-bio
+ * level, we store IO_BLOCKED in the appropriate 'bios' pointer
+ */
+#define IO_BLOCKED ((struct bio*)1)
+
+/* bits for r10bio.state */
+#define	R10BIO_Uptodate	0
+#define	R10BIO_IsSync	1
+#define	R10BIO_IsRecover 2
+#define	R10BIO_Degraded 3
+#endif
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index a5ba080..3bbc6d6 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -43,11 +43,14 @@
  * miss any bits.
  */
 
+#include <linux/blkdev.h>
 #include <linux/kthread.h>
-#include "raid6.h"
-
-#include <linux/raid/bitmap.h>
+#include <linux/raid/pq.h>
 #include <linux/async_tx.h>
+#include <linux/seq_file.h>
+#include "md.h"
+#include "raid5.h"
+#include "bitmap.h"
 
 /*
  * Stripe cache
@@ -91,11 +94,6 @@
 
 #define printk_rl(args...) ((void) (printk_ratelimit() && printk(args)))
 
-#if !RAID6_USE_EMPTY_ZERO_PAGE
-/* In .bss so it's zeroed */
-const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
-#endif
-
 /*
  * We maintain a biased count of active stripes in the bottom 16 bits of
  * bi_phys_segments, and a count of processed stripes in the upper 16 bits
@@ -130,12 +128,42 @@ static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt)
 	bio->bi_phys_segments = raid5_bi_phys_segments(bio) || (cnt << 16);
 }
 
+/* Find first data disk in a raid6 stripe */
+static inline int raid6_d0(struct stripe_head *sh)
+{
+	if (sh->ddf_layout)
+		/* ddf always start from first device */
+		return 0;
+	/* md starts just after Q block */
+	if (sh->qd_idx == sh->disks - 1)
+		return 0;
+	else
+		return sh->qd_idx + 1;
+}
 static inline int raid6_next_disk(int disk, int raid_disks)
 {
 	disk++;
 	return (disk < raid_disks) ? disk : 0;
 }
 
+/* When walking through the disks in a raid5, starting at raid6_d0,
+ * We need to map each disk to a 'slot', where the data disks are slot
+ * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
+ * is raid_disks-1.  This help does that mapping.
+ */
+static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
+			     int *count, int syndrome_disks)
+{
+	int slot;
+
+	if (idx == sh->pd_idx)
+		return syndrome_disks;
+	if (idx == sh->qd_idx)
+		return syndrome_disks + 1;
+	slot = (*count)++;
+	return slot;
+}
+
 static void return_io(struct bio *return_bi)
 {
 	struct bio *bi = return_bi;
@@ -193,6 +221,7 @@ static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
 		}
 	}
 }
+
 static void release_stripe(struct stripe_head *sh)
 {
 	raid5_conf_t *conf = sh->raid_conf;
@@ -270,9 +299,11 @@ static int grow_buffers(struct stripe_head *sh, int num)
 	return 0;
 }
 
-static void raid5_build_block(struct stripe_head *sh, int i);
+static void raid5_build_block(struct stripe_head *sh, int i, int previous);
+static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,
+			    struct stripe_head *sh);
 
-static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int disks)
+static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 {
 	raid5_conf_t *conf = sh->raid_conf;
 	int i;
@@ -287,11 +318,12 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int
 
 	remove_hash(sh);
 
+	sh->generation = conf->generation - previous;
+	sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 	sh->sector = sector;
-	sh->pd_idx = pd_idx;
+	stripe_set_idx(sector, conf, previous, sh);
 	sh->state = 0;
 
-	sh->disks = disks;
 
 	for (i = sh->disks; i--; ) {
 		struct r5dev *dev = &sh->dev[i];
@@ -305,12 +337,13 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int
 			BUG();
 		}
 		dev->flags = 0;
-		raid5_build_block(sh, i);
+		raid5_build_block(sh, i, previous);
 	}
 	insert_hash(conf, sh);
 }
 
-static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, int disks)
+static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector,
+					 short generation)
 {
 	struct stripe_head *sh;
 	struct hlist_node *hn;
@@ -318,7 +351,7 @@ static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, in
 	CHECK_DEVLOCK();
 	pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 	hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
-		if (sh->sector == sector && sh->disks == disks)
+		if (sh->sector == sector && sh->generation == generation)
 			return sh;
 	pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 	return NULL;
@@ -327,8 +360,9 @@ static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, in
 static void unplug_slaves(mddev_t *mddev);
 static void raid5_unplug_device(struct request_queue *q);
 
-static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector, int disks,
-					     int pd_idx, int noblock)
+static struct stripe_head *
+get_active_stripe(raid5_conf_t *conf, sector_t sector,
+		  int previous, int noblock)
 {
 	struct stripe_head *sh;
 
@@ -340,7 +374,7 @@ static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector
 		wait_event_lock_irq(conf->wait_for_stripe,
 				    conf->quiesce == 0,
 				    conf->device_lock, /* nothing */);
-		sh = __find_stripe(conf, sector, disks);
+		sh = __find_stripe(conf, sector, conf->generation - previous);
 		if (!sh) {
 			if (!conf->inactive_blocked)
 				sh = get_free_stripe(conf);
@@ -358,10 +392,11 @@ static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector
 					);
 				conf->inactive_blocked = 0;
 			} else
-				init_stripe(sh, sector, pd_idx, disks);
+				init_stripe(sh, sector, previous);
 		} else {
 			if (atomic_read(&sh->count)) {
-			  BUG_ON(!list_empty(&sh->lru));
+				BUG_ON(!list_empty(&sh->lru)
+				    && !test_bit(STRIPE_EXPANDING, &sh->state));
 			} else {
 				if (!test_bit(STRIPE_HANDLE, &sh->state))
 					atomic_inc(&conf->active_stripes);
@@ -895,8 +930,10 @@ static int grow_stripes(raid5_conf_t *conf, int num)
 	struct kmem_cache *sc;
 	int devs = conf->raid_disks;
 
-	sprintf(conf->cache_name[0], "raid5-%s", mdname(conf->mddev));
-	sprintf(conf->cache_name[1], "raid5-%s-alt", mdname(conf->mddev));
+	sprintf(conf->cache_name[0],
+		"raid%d-%s", conf->level, mdname(conf->mddev));
+	sprintf(conf->cache_name[1],
+		"raid%d-%s-alt", conf->level, mdname(conf->mddev));
 	conf->active_name = 0;
 	sc = kmem_cache_create(conf->cache_name[conf->active_name],
 			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
@@ -911,7 +948,6 @@ static int grow_stripes(raid5_conf_t *conf, int num)
 	return 0;
 }
 
-#ifdef CONFIG_MD_RAID5_RESHAPE
 static int resize_stripes(raid5_conf_t *conf, int newsize)
 {
 	/* Make all the stripes able to hold 'newsize' devices.
@@ -1036,7 +1072,6 @@ static int resize_stripes(raid5_conf_t *conf, int newsize)
 	conf->pool_size = newsize;
 	return err;
 }
-#endif
 
 static int drop_one_stripe(raid5_conf_t *conf)
 {
@@ -1066,7 +1101,7 @@ static void shrink_stripes(raid5_conf_t *conf)
 
 static void raid5_end_read_request(struct bio * bi, int error)
 {
- 	struct stripe_head *sh = bi->bi_private;
+	struct stripe_head *sh = bi->bi_private;
 	raid5_conf_t *conf = sh->raid_conf;
 	int disks = sh->disks, i;
 	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
@@ -1148,7 +1183,7 @@ static void raid5_end_read_request(struct bio * bi, int error)
 
 static void raid5_end_write_request(struct bio *bi, int error)
 {
- 	struct stripe_head *sh = bi->bi_private;
+	struct stripe_head *sh = bi->bi_private;
 	raid5_conf_t *conf = sh->raid_conf;
 	int disks = sh->disks, i;
 	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
@@ -1176,9 +1211,9 @@ static void raid5_end_write_request(struct bio *bi, int error)
 }
 
 
-static sector_t compute_blocknr(struct stripe_head *sh, int i);
+static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
 	
-static void raid5_build_block(struct stripe_head *sh, int i)
+static void raid5_build_block(struct stripe_head *sh, int i, int previous)
 {
 	struct r5dev *dev = &sh->dev[i];
 
@@ -1194,7 +1229,7 @@ static void raid5_build_block(struct stripe_head *sh, int i)
 	dev->req.bi_private = sh;
 
 	dev->flags = 0;
-	dev->sector = compute_blocknr(sh, i);
+	dev->sector = compute_blocknr(sh, i, previous);
 }
 
 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
@@ -1227,15 +1262,23 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev)
  * Input: a 'big' sector number,
  * Output: index of the data and parity disk, and the sector # in them.
  */
-static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks,
-			unsigned int data_disks, unsigned int * dd_idx,
-			unsigned int * pd_idx, raid5_conf_t *conf)
+static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector,
+				     int previous, int *dd_idx,
+				     struct stripe_head *sh)
 {
 	long stripe;
 	unsigned long chunk_number;
 	unsigned int chunk_offset;
+	int pd_idx, qd_idx;
+	int ddf_layout = 0;
 	sector_t new_sector;
-	int sectors_per_chunk = conf->chunk_size >> 9;
+	int algorithm = previous ? conf->prev_algo
+				 : conf->algorithm;
+	int sectors_per_chunk = previous ? (conf->prev_chunk >> 9)
+					 : (conf->chunk_size >> 9);
+	int raid_disks = previous ? conf->previous_raid_disks
+				  : conf->raid_disks;
+	int data_disks = raid_disks - conf->max_degraded;
 
 	/* First compute the information on this sector */
 
@@ -1259,68 +1302,170 @@ static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks,
 	/*
 	 * Select the parity disk based on the user selected algorithm.
 	 */
+	pd_idx = qd_idx = ~0;
 	switch(conf->level) {
 	case 4:
-		*pd_idx = data_disks;
+		pd_idx = data_disks;
 		break;
 	case 5:
-		switch (conf->algorithm) {
+		switch (algorithm) {
 		case ALGORITHM_LEFT_ASYMMETRIC:
-			*pd_idx = data_disks - stripe % raid_disks;
-			if (*dd_idx >= *pd_idx)
+			pd_idx = data_disks - stripe % raid_disks;
+			if (*dd_idx >= pd_idx)
 				(*dd_idx)++;
 			break;
 		case ALGORITHM_RIGHT_ASYMMETRIC:
-			*pd_idx = stripe % raid_disks;
-			if (*dd_idx >= *pd_idx)
+			pd_idx = stripe % raid_disks;
+			if (*dd_idx >= pd_idx)
 				(*dd_idx)++;
 			break;
 		case ALGORITHM_LEFT_SYMMETRIC:
-			*pd_idx = data_disks - stripe % raid_disks;
-			*dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
+			pd_idx = data_disks - stripe % raid_disks;
+			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
 			break;
 		case ALGORITHM_RIGHT_SYMMETRIC:
-			*pd_idx = stripe % raid_disks;
-			*dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
+			pd_idx = stripe % raid_disks;
+			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
+			break;
+		case ALGORITHM_PARITY_0:
+			pd_idx = 0;
+			(*dd_idx)++;
+			break;
+		case ALGORITHM_PARITY_N:
+			pd_idx = data_disks;
 			break;
 		default:
 			printk(KERN_ERR "raid5: unsupported algorithm %d\n",
-				conf->algorithm);
+				algorithm);
+			BUG();
 		}
 		break;
 	case 6:
 
-		/**** FIX THIS ****/
-		switch (conf->algorithm) {
+		switch (algorithm) {
 		case ALGORITHM_LEFT_ASYMMETRIC:
-			*pd_idx = raid_disks - 1 - (stripe % raid_disks);
-			if (*pd_idx == raid_disks-1)
-				(*dd_idx)++; 	/* Q D D D P */
-			else if (*dd_idx >= *pd_idx)
+			pd_idx = raid_disks - 1 - (stripe % raid_disks);
+			qd_idx = pd_idx + 1;
+			if (pd_idx == raid_disks-1) {
+				(*dd_idx)++;	/* Q D D D P */
+				qd_idx = 0;
+			} else if (*dd_idx >= pd_idx)
 				(*dd_idx) += 2; /* D D P Q D */
 			break;
 		case ALGORITHM_RIGHT_ASYMMETRIC:
-			*pd_idx = stripe % raid_disks;
-			if (*pd_idx == raid_disks-1)
-				(*dd_idx)++; 	/* Q D D D P */
-			else if (*dd_idx >= *pd_idx)
+			pd_idx = stripe % raid_disks;
+			qd_idx = pd_idx + 1;
+			if (pd_idx == raid_disks-1) {
+				(*dd_idx)++;	/* Q D D D P */
+				qd_idx = 0;
+			} else if (*dd_idx >= pd_idx)
 				(*dd_idx) += 2; /* D D P Q D */
 			break;
 		case ALGORITHM_LEFT_SYMMETRIC:
-			*pd_idx = raid_disks - 1 - (stripe % raid_disks);
-			*dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
+			pd_idx = raid_disks - 1 - (stripe % raid_disks);
+			qd_idx = (pd_idx + 1) % raid_disks;
+			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
 			break;
 		case ALGORITHM_RIGHT_SYMMETRIC:
-			*pd_idx = stripe % raid_disks;
-			*dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
+			pd_idx = stripe % raid_disks;
+			qd_idx = (pd_idx + 1) % raid_disks;
+			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
+			break;
+
+		case ALGORITHM_PARITY_0:
+			pd_idx = 0;
+			qd_idx = 1;
+			(*dd_idx) += 2;
+			break;
+		case ALGORITHM_PARITY_N:
+			pd_idx = data_disks;
+			qd_idx = data_disks + 1;
 			break;
+
+		case ALGORITHM_ROTATING_ZERO_RESTART:
+			/* Exactly the same as RIGHT_ASYMMETRIC, but or
+			 * of blocks for computing Q is different.
+			 */
+			pd_idx = stripe % raid_disks;
+			qd_idx = pd_idx + 1;
+			if (pd_idx == raid_disks-1) {
+				(*dd_idx)++;	/* Q D D D P */
+				qd_idx = 0;
+			} else if (*dd_idx >= pd_idx)
+				(*dd_idx) += 2; /* D D P Q D */
+			ddf_layout = 1;
+			break;
+
+		case ALGORITHM_ROTATING_N_RESTART:
+			/* Same a left_asymmetric, by first stripe is
+			 * D D D P Q  rather than
+			 * Q D D D P
+			 */
+			pd_idx = raid_disks - 1 - ((stripe + 1) % raid_disks);
+			qd_idx = pd_idx + 1;
+			if (pd_idx == raid_disks-1) {
+				(*dd_idx)++;	/* Q D D D P */
+				qd_idx = 0;
+			} else if (*dd_idx >= pd_idx)
+				(*dd_idx) += 2; /* D D P Q D */
+			ddf_layout = 1;
+			break;
+
+		case ALGORITHM_ROTATING_N_CONTINUE:
+			/* Same as left_symmetric but Q is before P */
+			pd_idx = raid_disks - 1 - (stripe % raid_disks);
+			qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
+			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
+			ddf_layout = 1;
+			break;
+
+		case ALGORITHM_LEFT_ASYMMETRIC_6:
+			/* RAID5 left_asymmetric, with Q on last device */
+			pd_idx = data_disks - stripe % (raid_disks-1);
+			if (*dd_idx >= pd_idx)
+				(*dd_idx)++;
+			qd_idx = raid_disks - 1;
+			break;
+
+		case ALGORITHM_RIGHT_ASYMMETRIC_6:
+			pd_idx = stripe % (raid_disks-1);
+			if (*dd_idx >= pd_idx)
+				(*dd_idx)++;
+			qd_idx = raid_disks - 1;
+			break;
+
+		case ALGORITHM_LEFT_SYMMETRIC_6:
+			pd_idx = data_disks - stripe % (raid_disks-1);
+			*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
+			qd_idx = raid_disks - 1;
+			break;
+
+		case ALGORITHM_RIGHT_SYMMETRIC_6:
+			pd_idx = stripe % (raid_disks-1);
+			*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
+			qd_idx = raid_disks - 1;
+			break;
+
+		case ALGORITHM_PARITY_0_6:
+			pd_idx = 0;
+			(*dd_idx)++;
+			qd_idx = raid_disks - 1;
+			break;
+
+
 		default:
 			printk(KERN_CRIT "raid6: unsupported algorithm %d\n",
-			       conf->algorithm);
+			       algorithm);
+			BUG();
 		}
 		break;
 	}
 
+	if (sh) {
+		sh->pd_idx = pd_idx;
+		sh->qd_idx = qd_idx;
+		sh->ddf_layout = ddf_layout;
+	}
 	/*
 	 * Finally, compute the new sector number
 	 */
@@ -1329,17 +1474,21 @@ static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks,
 }
 
 
-static sector_t compute_blocknr(struct stripe_head *sh, int i)
+static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
 {
 	raid5_conf_t *conf = sh->raid_conf;
 	int raid_disks = sh->disks;
 	int data_disks = raid_disks - conf->max_degraded;
 	sector_t new_sector = sh->sector, check;
-	int sectors_per_chunk = conf->chunk_size >> 9;
+	int sectors_per_chunk = previous ? (conf->prev_chunk >> 9)
+					 : (conf->chunk_size >> 9);
+	int algorithm = previous ? conf->prev_algo
+				 : conf->algorithm;
 	sector_t stripe;
 	int chunk_offset;
-	int chunk_number, dummy1, dummy2, dd_idx = i;
+	int chunk_number, dummy1, dd_idx = i;
 	sector_t r_sector;
+	struct stripe_head sh2;
 
 
 	chunk_offset = sector_div(new_sector, sectors_per_chunk);
@@ -1351,7 +1500,7 @@ static sector_t compute_blocknr(struct stripe_head *sh, int i)
 	switch(conf->level) {
 	case 4: break;
 	case 5:
-		switch (conf->algorithm) {
+		switch (algorithm) {
 		case ALGORITHM_LEFT_ASYMMETRIC:
 		case ALGORITHM_RIGHT_ASYMMETRIC:
 			if (i > sh->pd_idx)
@@ -1363,19 +1512,27 @@ static sector_t compute_blocknr(struct stripe_head *sh, int i)
 				i += raid_disks;
 			i -= (sh->pd_idx + 1);
 			break;
+		case ALGORITHM_PARITY_0:
+			i -= 1;
+			break;
+		case ALGORITHM_PARITY_N:
+			break;
 		default:
 			printk(KERN_ERR "raid5: unsupported algorithm %d\n",
-			       conf->algorithm);
+			       algorithm);
+			BUG();
 		}
 		break;
 	case 6:
-		if (i == raid6_next_disk(sh->pd_idx, raid_disks))
+		if (i == sh->qd_idx)
 			return 0; /* It is the Q disk */
-		switch (conf->algorithm) {
+		switch (algorithm) {
 		case ALGORITHM_LEFT_ASYMMETRIC:
 		case ALGORITHM_RIGHT_ASYMMETRIC:
-		  	if (sh->pd_idx == raid_disks-1)
-				i--; 	/* Q D D D P */
+		case ALGORITHM_ROTATING_ZERO_RESTART:
+		case ALGORITHM_ROTATING_N_RESTART:
+			if (sh->pd_idx == raid_disks-1)
+				i--;	/* Q D D D P */
 			else if (i > sh->pd_idx)
 				i -= 2; /* D D P Q D */
 			break;
@@ -1390,9 +1547,35 @@ static sector_t compute_blocknr(struct stripe_head *sh, int i)
 				i -= (sh->pd_idx + 2);
 			}
 			break;
+		case ALGORITHM_PARITY_0:
+			i -= 2;
+			break;
+		case ALGORITHM_PARITY_N:
+			break;
+		case ALGORITHM_ROTATING_N_CONTINUE:
+			if (sh->pd_idx == 0)
+				i--;	/* P D D D Q */
+			else if (i > sh->pd_idx)
+				i -= 2; /* D D Q P D */
+			break;
+		case ALGORITHM_LEFT_ASYMMETRIC_6:
+		case ALGORITHM_RIGHT_ASYMMETRIC_6:
+			if (i > sh->pd_idx)
+				i--;
+			break;
+		case ALGORITHM_LEFT_SYMMETRIC_6:
+		case ALGORITHM_RIGHT_SYMMETRIC_6:
+			if (i < sh->pd_idx)
+				i += data_disks + 1;
+			i -= (sh->pd_idx + 1);
+			break;
+		case ALGORITHM_PARITY_0_6:
+			i -= 1;
+			break;
 		default:
 			printk(KERN_CRIT "raid6: unsupported algorithm %d\n",
-			       conf->algorithm);
+			       algorithm);
+			BUG();
 		}
 		break;
 	}
@@ -1400,8 +1583,10 @@ static sector_t compute_blocknr(struct stripe_head *sh, int i)
 	chunk_number = stripe * data_disks + i;
 	r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
 
-	check = raid5_compute_sector(r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
-	if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
+	check = raid5_compute_sector(conf, r_sector,
+				     previous, &dummy1, &sh2);
+	if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
+		|| sh2.qd_idx != sh->qd_idx) {
 		printk(KERN_ERR "compute_blocknr: map not correct\n");
 		return 0;
 	}
@@ -1468,14 +1653,16 @@ static void copy_data(int frombio, struct bio *bio,
 
 static void compute_parity6(struct stripe_head *sh, int method)
 {
-	raid6_conf_t *conf = sh->raid_conf;
-	int i, pd_idx = sh->pd_idx, qd_idx, d0_idx, disks = sh->disks, count;
+	raid5_conf_t *conf = sh->raid_conf;
+	int i, pd_idx, qd_idx, d0_idx, disks = sh->disks, count;
+	int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
 	struct bio *chosen;
 	/**** FIX THIS: This could be very bad if disks is close to 256 ****/
-	void *ptrs[disks];
+	void *ptrs[syndrome_disks+2];
 
-	qd_idx = raid6_next_disk(pd_idx, disks);
-	d0_idx = raid6_next_disk(qd_idx, disks);
+	pd_idx = sh->pd_idx;
+	qd_idx = sh->qd_idx;
+	d0_idx = raid6_d0(sh);
 
 	pr_debug("compute_parity, stripe %llu, method %d\n",
 		(unsigned long long)sh->sector, method);
@@ -1513,24 +1700,29 @@ static void compute_parity6(struct stripe_head *sh, int method)
 			set_bit(R5_UPTODATE, &sh->dev[i].flags);
 		}
 
-//	switch(method) {
-//	case RECONSTRUCT_WRITE:
-//	case CHECK_PARITY:
-//	case UPDATE_PARITY:
-		/* Note that unlike RAID-5, the ordering of the disks matters greatly. */
-		/* FIX: Is this ordering of drives even remotely optimal? */
-		count = 0;
-		i = d0_idx;
-		do {
-			ptrs[count++] = page_address(sh->dev[i].page);
-			if (count <= disks-2 && !test_bit(R5_UPTODATE, &sh->dev[i].flags))
-				printk("block %d/%d not uptodate on parity calc\n", i,count);
-			i = raid6_next_disk(i, disks);
-		} while ( i != d0_idx );
-//		break;
-//	}
-
-	raid6_call.gen_syndrome(disks, STRIPE_SIZE, ptrs);
+	/* Note that unlike RAID-5, the ordering of the disks matters greatly.*/
+
+	for (i = 0; i < disks; i++)
+		ptrs[i] = (void *)raid6_empty_zero_page;
+
+	count = 0;
+	i = d0_idx;
+	do {
+		int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
+
+		ptrs[slot] = page_address(sh->dev[i].page);
+		if (slot < syndrome_disks &&
+		    !test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
+			printk(KERN_ERR "block %d/%d not uptodate "
+			       "on parity calc\n", i, count);
+			BUG();
+		}
+
+		i = raid6_next_disk(i, disks);
+	} while (i != d0_idx);
+	BUG_ON(count != syndrome_disks);
+
+	raid6_call.gen_syndrome(syndrome_disks+2, STRIPE_SIZE, ptrs);
 
 	switch(method) {
 	case RECONSTRUCT_WRITE:
@@ -1552,8 +1744,7 @@ static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero)
 {
 	int i, count, disks = sh->disks;
 	void *ptr[MAX_XOR_BLOCKS], *dest, *p;
-	int pd_idx = sh->pd_idx;
-	int qd_idx = raid6_next_disk(pd_idx, disks);
+	int qd_idx = sh->qd_idx;
 
 	pr_debug("compute_block_1, stripe %llu, idx %d\n",
 		(unsigned long long)sh->sector, dd_idx);
@@ -1589,63 +1780,65 @@ static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero)
 static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
 {
 	int i, count, disks = sh->disks;
-	int pd_idx = sh->pd_idx;
-	int qd_idx = raid6_next_disk(pd_idx, disks);
-	int d0_idx = raid6_next_disk(qd_idx, disks);
-	int faila, failb;
+	int syndrome_disks = sh->ddf_layout ? disks : disks-2;
+	int d0_idx = raid6_d0(sh);
+	int faila = -1, failb = -1;
+	/**** FIX THIS: This could be very bad if disks is close to 256 ****/
+	void *ptrs[syndrome_disks+2];
 
-	/* faila and failb are disk numbers relative to d0_idx */
-	/* pd_idx become disks-2 and qd_idx become disks-1 */
-	faila = (dd_idx1 < d0_idx) ? dd_idx1+(disks-d0_idx) : dd_idx1-d0_idx;
-	failb = (dd_idx2 < d0_idx) ? dd_idx2+(disks-d0_idx) : dd_idx2-d0_idx;
+	for (i = 0; i < disks ; i++)
+		ptrs[i] = (void *)raid6_empty_zero_page;
+	count = 0;
+	i = d0_idx;
+	do {
+		int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
+
+		ptrs[slot] = page_address(sh->dev[i].page);
+
+		if (i == dd_idx1)
+			faila = slot;
+		if (i == dd_idx2)
+			failb = slot;
+		i = raid6_next_disk(i, disks);
+	} while (i != d0_idx);
+	BUG_ON(count != syndrome_disks);
 
 	BUG_ON(faila == failb);
 	if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; }
 
 	pr_debug("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n",
-	       (unsigned long long)sh->sector, dd_idx1, dd_idx2, faila, failb);
+		 (unsigned long long)sh->sector, dd_idx1, dd_idx2,
+		 faila, failb);
 
-	if ( failb == disks-1 ) {
+	if (failb == syndrome_disks+1) {
 		/* Q disk is one of the missing disks */
-		if ( faila == disks-2 ) {
+		if (faila == syndrome_disks) {
 			/* Missing P+Q, just recompute */
 			compute_parity6(sh, UPDATE_PARITY);
 			return;
 		} else {
 			/* We're missing D+Q; recompute D from P */
-			compute_block_1(sh, (dd_idx1 == qd_idx) ? dd_idx2 : dd_idx1, 0);
+			compute_block_1(sh, ((dd_idx1 == sh->qd_idx) ?
+					     dd_idx2 : dd_idx1),
+					0);
 			compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */
 			return;
 		}
 	}
 
-	/* We're missing D+P or D+D; build pointer table */
-	{
-		/**** FIX THIS: This could be very bad if disks is close to 256 ****/
-		void *ptrs[disks];
-
-		count = 0;
-		i = d0_idx;
-		do {
-			ptrs[count++] = page_address(sh->dev[i].page);
-			i = raid6_next_disk(i, disks);
-			if (i != dd_idx1 && i != dd_idx2 &&
-			    !test_bit(R5_UPTODATE, &sh->dev[i].flags))
-				printk("compute_2 with missing block %d/%d\n", count, i);
-		} while ( i != d0_idx );
-
-		if ( failb == disks-2 ) {
-			/* We're missing D+P. */
-			raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs);
-		} else {
-			/* We're missing D+D. */
-			raid6_2data_recov(disks, STRIPE_SIZE, faila, failb, ptrs);
-		}
-
-		/* Both the above update both missing blocks */
-		set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags);
-		set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags);
+	/* We're missing D+P or D+D; */
+	if (failb == syndrome_disks) {
+		/* We're missing D+P. */
+		raid6_datap_recov(syndrome_disks+2, STRIPE_SIZE, faila, ptrs);
+	} else {
+		/* We're missing D+D. */
+		raid6_2data_recov(syndrome_disks+2, STRIPE_SIZE, faila, failb,
+				  ptrs);
 	}
+
+	/* Both the above update both missing blocks */
+	set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags);
+	set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags);
 }
 
 static void
@@ -1800,17 +1993,21 @@ static int page_is_zero(struct page *p)
 		memcmp(a, a+4, STRIPE_SIZE-4)==0);
 }
 
-static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)
+static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,
+			    struct stripe_head *sh)
 {
-	int sectors_per_chunk = conf->chunk_size >> 9;
-	int pd_idx, dd_idx;
+	int sectors_per_chunk =
+		previous ? (conf->prev_chunk >> 9)
+			 : (conf->chunk_size >> 9);
+	int dd_idx;
 	int chunk_offset = sector_div(stripe, sectors_per_chunk);
+	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 
-	raid5_compute_sector(stripe * (disks - conf->max_degraded)
+	raid5_compute_sector(conf,
+			     stripe * (disks - conf->max_degraded)
 			     *sectors_per_chunk + chunk_offset,
-			     disks, disks - conf->max_degraded,
-			     &dd_idx, &pd_idx, conf);
-	return pd_idx;
+			     previous,
+			     &dd_idx, sh);
 }
 
 static void
@@ -2181,7 +2378,7 @@ static void handle_stripe_dirtying6(raid5_conf_t *conf,
 		struct r6_state *r6s, int disks)
 {
 	int rcw = 0, must_compute = 0, pd_idx = sh->pd_idx, i;
-	int qd_idx = r6s->qd_idx;
+	int qd_idx = sh->qd_idx;
 	for (i = disks; i--; ) {
 		struct r5dev *dev = &sh->dev[i];
 		/* Would I have to read this buffer for reconstruct_write */
@@ -2371,7 +2568,7 @@ static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh,
 	int update_p = 0, update_q = 0;
 	struct r5dev *dev;
 	int pd_idx = sh->pd_idx;
-	int qd_idx = r6s->qd_idx;
+	int qd_idx = sh->qd_idx;
 
 	set_bit(STRIPE_HANDLE, &sh->state);
 
@@ -2467,17 +2664,14 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
 	struct dma_async_tx_descriptor *tx = NULL;
 	clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
 	for (i = 0; i < sh->disks; i++)
-		if (i != sh->pd_idx && (!r6s || i != r6s->qd_idx)) {
-			int dd_idx, pd_idx, j;
+		if (i != sh->pd_idx && i != sh->qd_idx) {
+			int dd_idx, j;
 			struct stripe_head *sh2;
 
-			sector_t bn = compute_blocknr(sh, i);
-			sector_t s = raid5_compute_sector(bn, conf->raid_disks,
-						conf->raid_disks -
-						conf->max_degraded, &dd_idx,
-						&pd_idx, conf);
-			sh2 = get_active_stripe(conf, s, conf->raid_disks,
-						pd_idx, 1);
+			sector_t bn = compute_blocknr(sh, i, 1);
+			sector_t s = raid5_compute_sector(conf, bn, 0,
+							  &dd_idx, NULL);
+			sh2 = get_active_stripe(conf, s, 0, 1);
 			if (sh2 == NULL)
 				/* so far only the early blocks of this stripe
 				 * have been requested.  When later blocks
@@ -2500,8 +2694,7 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
 			set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
 			for (j = 0; j < conf->raid_disks; j++)
 				if (j != sh2->pd_idx &&
-				    (!r6s || j != raid6_next_disk(sh2->pd_idx,
-								 sh2->disks)) &&
+				    (!r6s || j != sh2->qd_idx) &&
 				    !test_bit(R5_Expanded, &sh2->dev[j].flags))
 					break;
 			if (j == conf->raid_disks) {
@@ -2750,6 +2943,23 @@ static bool handle_stripe5(struct stripe_head *sh)
 
 	/* Finish reconstruct operations initiated by the expansion process */
 	if (sh->reconstruct_state == reconstruct_state_result) {
+		struct stripe_head *sh2
+			= get_active_stripe(conf, sh->sector, 1, 1);
+		if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) {
+			/* sh cannot be written until sh2 has been read.
+			 * so arrange for sh to be delayed a little
+			 */
+			set_bit(STRIPE_DELAYED, &sh->state);
+			set_bit(STRIPE_HANDLE, &sh->state);
+			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
+					      &sh2->state))
+				atomic_inc(&conf->preread_active_stripes);
+			release_stripe(sh2);
+			goto unlock;
+		}
+		if (sh2)
+			release_stripe(sh2);
+
 		sh->reconstruct_state = reconstruct_state_idle;
 		clear_bit(STRIPE_EXPANDING, &sh->state);
 		for (i = conf->raid_disks; i--; ) {
@@ -2763,8 +2973,7 @@ static bool handle_stripe5(struct stripe_head *sh)
 	    !sh->reconstruct_state) {
 		/* Need to write out all blocks after computing parity */
 		sh->disks = conf->raid_disks;
-		sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
-			conf->raid_disks);
+		stripe_set_idx(sh->sector, conf, 0, sh);
 		schedule_reconstruction5(sh, &s, 1, 1);
 	} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
 		clear_bit(STRIPE_EXPAND_READY, &sh->state);
@@ -2796,20 +3005,19 @@ static bool handle_stripe5(struct stripe_head *sh)
 
 static bool handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
 {
-	raid6_conf_t *conf = sh->raid_conf;
+	raid5_conf_t *conf = sh->raid_conf;
 	int disks = sh->disks;
 	struct bio *return_bi = NULL;
-	int i, pd_idx = sh->pd_idx;
+	int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx;
 	struct stripe_head_state s;
 	struct r6_state r6s;
 	struct r5dev *dev, *pdev, *qdev;
 	mdk_rdev_t *blocked_rdev = NULL;
 
-	r6s.qd_idx = raid6_next_disk(pd_idx, disks);
 	pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
 		"pd_idx=%d, qd_idx=%d\n",
 	       (unsigned long long)sh->sector, sh->state,
-	       atomic_read(&sh->count), pd_idx, r6s.qd_idx);
+	       atomic_read(&sh->count), pd_idx, qd_idx);
 	memset(&s, 0, sizeof(s));
 
 	spin_lock(&sh->lock);
@@ -2920,9 +3128,9 @@ static bool handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
 	pdev = &sh->dev[pd_idx];
 	r6s.p_failed = (s.failed >= 1 && r6s.failed_num[0] == pd_idx)
 		|| (s.failed >= 2 && r6s.failed_num[1] == pd_idx);
-	qdev = &sh->dev[r6s.qd_idx];
-	r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == r6s.qd_idx)
-		|| (s.failed >= 2 && r6s.failed_num[1] == r6s.qd_idx);
+	qdev = &sh->dev[qd_idx];
+	r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == qd_idx)
+		|| (s.failed >= 2 && r6s.failed_num[1] == qd_idx);
 
 	if ( s.written &&
 	     ( r6s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
@@ -2980,10 +3188,26 @@ static bool handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
 		}
 
 	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
+		struct stripe_head *sh2
+			= get_active_stripe(conf, sh->sector, 1, 1);
+		if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) {
+			/* sh cannot be written until sh2 has been read.
+			 * so arrange for sh to be delayed a little
+			 */
+			set_bit(STRIPE_DELAYED, &sh->state);
+			set_bit(STRIPE_HANDLE, &sh->state);
+			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
+					      &sh2->state))
+				atomic_inc(&conf->preread_active_stripes);
+			release_stripe(sh2);
+			goto unlock;
+		}
+		if (sh2)
+			release_stripe(sh2);
+
 		/* Need to write out all blocks after computing P&Q */
 		sh->disks = conf->raid_disks;
-		sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
-					     conf->raid_disks);
+		stripe_set_idx(sh->sector, conf, 0, sh);
 		compute_parity6(sh, RECONSTRUCT_WRITE);
 		for (i = conf->raid_disks ; i-- ;  ) {
 			set_bit(R5_LOCKED, &sh->dev[i].flags);
@@ -3134,6 +3358,8 @@ static int raid5_mergeable_bvec(struct request_queue *q,
 	if ((bvm->bi_rw & 1) == WRITE)
 		return biovec->bv_len; /* always allow writes to be mergeable */
 
+	if (mddev->new_chunk < mddev->chunk_size)
+		chunk_sectors = mddev->new_chunk >> 9;
 	max =  (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
 	if (max < 0) max = 0;
 	if (max <= biovec->bv_len && bio_sectors == 0)
@@ -3149,6 +3375,8 @@ static int in_chunk_boundary(mddev_t *mddev, struct bio *bio)
 	unsigned int chunk_sectors = mddev->chunk_size >> 9;
 	unsigned int bio_sectors = bio->bi_size >> 9;
 
+	if (mddev->new_chunk < mddev->chunk_size)
+		chunk_sectors = mddev->new_chunk >> 9;
 	return  chunk_sectors >=
 		((sector & (chunk_sectors - 1)) + bio_sectors);
 }
@@ -3255,9 +3483,7 @@ static int chunk_aligned_read(struct request_queue *q, struct bio * raid_bio)
 {
 	mddev_t *mddev = q->queuedata;
 	raid5_conf_t *conf = mddev_to_conf(mddev);
-	const unsigned int raid_disks = conf->raid_disks;
-	const unsigned int data_disks = raid_disks - conf->max_degraded;
-	unsigned int dd_idx, pd_idx;
+	unsigned int dd_idx;
 	struct bio* align_bi;
 	mdk_rdev_t *rdev;
 
@@ -3266,7 +3492,7 @@ static int chunk_aligned_read(struct request_queue *q, struct bio * raid_bio)
 		return 0;
 	}
 	/*
- 	 * use bio_clone to make a copy of the bio
+	 * use bio_clone to make a copy of the bio
 	 */
 	align_bi = bio_clone(raid_bio, GFP_NOIO);
 	if (!align_bi)
@@ -3280,12 +3506,9 @@ static int chunk_aligned_read(struct request_queue *q, struct bio * raid_bio)
 	/*
 	 *	compute position
 	 */
-	align_bi->bi_sector =  raid5_compute_sector(raid_bio->bi_sector,
-					raid_disks,
-					data_disks,
-					&dd_idx,
-					&pd_idx,
-					conf);
+	align_bi->bi_sector =  raid5_compute_sector(conf, raid_bio->bi_sector,
+						    0,
+						    &dd_idx, NULL);
 
 	rcu_read_lock();
 	rdev = rcu_dereference(conf->disks[dd_idx].rdev);
@@ -3377,7 +3600,7 @@ static int make_request(struct request_queue *q, struct bio * bi)
 {
 	mddev_t *mddev = q->queuedata;
 	raid5_conf_t *conf = mddev_to_conf(mddev);
-	unsigned int dd_idx, pd_idx;
+	int dd_idx;
 	sector_t new_sector;
 	sector_t logical_sector, last_sector;
 	struct stripe_head *sh;
@@ -3400,7 +3623,7 @@ static int make_request(struct request_queue *q, struct bio * bi)
 	if (rw == READ &&
 	     mddev->reshape_position == MaxSector &&
 	     chunk_aligned_read(q,bi))
-            	return 0;
+		return 0;
 
 	logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
 	last_sector = bi->bi_sector + (bi->bi_size>>9);
@@ -3410,26 +3633,31 @@ static int make_request(struct request_queue *q, struct bio * bi)
 	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
 		DEFINE_WAIT(w);
 		int disks, data_disks;
+		int previous;
 
 	retry:
+		previous = 0;
+		disks = conf->raid_disks;
 		prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
-		if (likely(conf->expand_progress == MaxSector))
-			disks = conf->raid_disks;
-		else {
-			/* spinlock is needed as expand_progress may be
+		if (unlikely(conf->reshape_progress != MaxSector)) {
+			/* spinlock is needed as reshape_progress may be
 			 * 64bit on a 32bit platform, and so it might be
 			 * possible to see a half-updated value
-			 * Ofcourse expand_progress could change after
+			 * Ofcourse reshape_progress could change after
 			 * the lock is dropped, so once we get a reference
 			 * to the stripe that we think it is, we will have
 			 * to check again.
 			 */
 			spin_lock_irq(&conf->device_lock);
-			disks = conf->raid_disks;
-			if (logical_sector >= conf->expand_progress)
+			if (mddev->delta_disks < 0
+			    ? logical_sector < conf->reshape_progress
+			    : logical_sector >= conf->reshape_progress) {
 				disks = conf->previous_raid_disks;
-			else {
-				if (logical_sector >= conf->expand_lo) {
+				previous = 1;
+			} else {
+				if (mddev->delta_disks < 0
+				    ? logical_sector < conf->reshape_safe
+				    : logical_sector >= conf->reshape_safe) {
 					spin_unlock_irq(&conf->device_lock);
 					schedule();
 					goto retry;
@@ -3439,15 +3667,17 @@ static int make_request(struct request_queue *q, struct bio * bi)
 		}
 		data_disks = disks - conf->max_degraded;
 
- 		new_sector = raid5_compute_sector(logical_sector, disks, data_disks,
-						  &dd_idx, &pd_idx, conf);
+		new_sector = raid5_compute_sector(conf, logical_sector,
+						  previous,
+						  &dd_idx, NULL);
 		pr_debug("raid5: make_request, sector %llu logical %llu\n",
 			(unsigned long long)new_sector, 
 			(unsigned long long)logical_sector);
 
-		sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK));
+		sh = get_active_stripe(conf, new_sector, previous,
+				       (bi->bi_rw&RWA_MASK));
 		if (sh) {
-			if (unlikely(conf->expand_progress != MaxSector)) {
+			if (unlikely(previous)) {
 				/* expansion might have moved on while waiting for a
 				 * stripe, so we must do the range check again.
 				 * Expansion could still move past after this
@@ -3458,8 +3688,9 @@ static int make_request(struct request_queue *q, struct bio * bi)
 				 */
 				int must_retry = 0;
 				spin_lock_irq(&conf->device_lock);
-				if (logical_sector <  conf->expand_progress &&
-				    disks == conf->previous_raid_disks)
+				if (mddev->delta_disks < 0
+				    ? logical_sector >= conf->reshape_progress
+				    : logical_sector < conf->reshape_progress)
 					/* mismatch, need to try again */
 					must_retry = 1;
 				spin_unlock_irq(&conf->device_lock);
@@ -3514,6 +3745,8 @@ static int make_request(struct request_queue *q, struct bio * bi)
 	return 0;
 }
 
+static sector_t raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks);
+
 static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped)
 {
 	/* reshaping is quite different to recovery/resync so it is
@@ -3527,61 +3760,118 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
 	 */
 	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
 	struct stripe_head *sh;
-	int pd_idx;
 	sector_t first_sector, last_sector;
 	int raid_disks = conf->previous_raid_disks;
 	int data_disks = raid_disks - conf->max_degraded;
 	int new_data_disks = conf->raid_disks - conf->max_degraded;
 	int i;
 	int dd_idx;
-	sector_t writepos, safepos, gap;
-
-	if (sector_nr == 0 &&
-	    conf->expand_progress != 0) {
-		/* restarting in the middle, skip the initial sectors */
-		sector_nr = conf->expand_progress;
+	sector_t writepos, readpos, safepos;
+	sector_t stripe_addr;
+	int reshape_sectors;
+	struct list_head stripes;
+
+	if (sector_nr == 0) {
+		/* If restarting in the middle, skip the initial sectors */
+		if (mddev->delta_disks < 0 &&
+		    conf->reshape_progress < raid5_size(mddev, 0, 0)) {
+			sector_nr = raid5_size(mddev, 0, 0)
+				- conf->reshape_progress;
+		} else if (mddev->delta_disks > 0 &&
+			   conf->reshape_progress > 0)
+			sector_nr = conf->reshape_progress;
 		sector_div(sector_nr, new_data_disks);
-		*skipped = 1;
-		return sector_nr;
+		if (sector_nr) {
+			*skipped = 1;
+			return sector_nr;
+		}
 	}
 
+	/* We need to process a full chunk at a time.
+	 * If old and new chunk sizes differ, we need to process the
+	 * largest of these
+	 */
+	if (mddev->new_chunk > mddev->chunk_size)
+		reshape_sectors = mddev->new_chunk / 512;
+	else
+		reshape_sectors = mddev->chunk_size / 512;
+
 	/* we update the metadata when there is more than 3Meg
 	 * in the block range (that is rather arbitrary, should
 	 * probably be time based) or when the data about to be
 	 * copied would over-write the source of the data at
 	 * the front of the range.
-	 * i.e. one new_stripe forward from expand_progress new_maps
-	 * to after where expand_lo old_maps to
+	 * i.e. one new_stripe along from reshape_progress new_maps
+	 * to after where reshape_safe old_maps to
 	 */
-	writepos = conf->expand_progress +
-		conf->chunk_size/512*(new_data_disks);
+	writepos = conf->reshape_progress;
 	sector_div(writepos, new_data_disks);
-	safepos = conf->expand_lo;
+	readpos = conf->reshape_progress;
+	sector_div(readpos, data_disks);
+	safepos = conf->reshape_safe;
 	sector_div(safepos, data_disks);
-	gap = conf->expand_progress - conf->expand_lo;
+	if (mddev->delta_disks < 0) {
+		writepos -= reshape_sectors;
+		readpos += reshape_sectors;
+		safepos += reshape_sectors;
+	} else {
+		writepos += reshape_sectors;
+		readpos -= reshape_sectors;
+		safepos -= reshape_sectors;
+	}
 
-	if (writepos >= safepos ||
-	    gap > (new_data_disks)*3000*2 /*3Meg*/) {
+	/* 'writepos' is the most advanced device address we might write.
+	 * 'readpos' is the least advanced device address we might read.
+	 * 'safepos' is the least address recorded in the metadata as having
+	 *     been reshaped.
+	 * If 'readpos' is behind 'writepos', then there is no way that we can
+	 * ensure safety in the face of a crash - that must be done by userspace
+	 * making a backup of the data.  So in that case there is no particular
+	 * rush to update metadata.
+	 * Otherwise if 'safepos' is behind 'writepos', then we really need to
+	 * update the metadata to advance 'safepos' to match 'readpos' so that
+	 * we can be safe in the event of a crash.
+	 * So we insist on updating metadata if safepos is behind writepos and
+	 * readpos is beyond writepos.
+	 * In any case, update the metadata every 10 seconds.
+	 * Maybe that number should be configurable, but I'm not sure it is
+	 * worth it.... maybe it could be a multiple of safemode_delay???
+	 */
+	if ((mddev->delta_disks < 0
+	     ? (safepos > writepos && readpos < writepos)
+	     : (safepos < writepos && readpos > writepos)) ||
+	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
 		/* Cannot proceed until we've updated the superblock... */
 		wait_event(conf->wait_for_overlap,
 			   atomic_read(&conf->reshape_stripes)==0);
-		mddev->reshape_position = conf->expand_progress;
+		mddev->reshape_position = conf->reshape_progress;
+		conf->reshape_checkpoint = jiffies;
 		set_bit(MD_CHANGE_DEVS, &mddev->flags);
 		md_wakeup_thread(mddev->thread);
 		wait_event(mddev->sb_wait, mddev->flags == 0 ||
 			   kthread_should_stop());
 		spin_lock_irq(&conf->device_lock);
-		conf->expand_lo = mddev->reshape_position;
+		conf->reshape_safe = mddev->reshape_position;
 		spin_unlock_irq(&conf->device_lock);
 		wake_up(&conf->wait_for_overlap);
 	}
 
-	for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) {
+	if (mddev->delta_disks < 0) {
+		BUG_ON(conf->reshape_progress == 0);
+		stripe_addr = writepos;
+		BUG_ON((mddev->dev_sectors &
+			~((sector_t)reshape_sectors - 1))
+		       - reshape_sectors - stripe_addr
+		       != sector_nr);
+	} else {
+		BUG_ON(writepos != sector_nr + reshape_sectors);
+		stripe_addr = sector_nr;
+	}
+	INIT_LIST_HEAD(&stripes);
+	for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
 		int j;
 		int skipped = 0;
-		pd_idx = stripe_to_pdidx(sector_nr+i, conf, conf->raid_disks);
-		sh = get_active_stripe(conf, sector_nr+i,
-				       conf->raid_disks, pd_idx, 0);
+		sh = get_active_stripe(conf, stripe_addr+i, 0, 0);
 		set_bit(STRIPE_EXPANDING, &sh->state);
 		atomic_inc(&conf->reshape_stripes);
 		/* If any of this stripe is beyond the end of the old
@@ -3592,10 +3882,10 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
 			if (j == sh->pd_idx)
 				continue;
 			if (conf->level == 6 &&
-			    j == raid6_next_disk(sh->pd_idx, sh->disks))
+			    j == sh->qd_idx)
 				continue;
-			s = compute_blocknr(sh, j);
-			if (s < mddev->array_sectors) {
+			s = compute_blocknr(sh, j, 0);
+			if (s < raid5_size(mddev, 0, 0)) {
 				skipped = 1;
 				continue;
 			}
@@ -3607,10 +3897,13 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
 			set_bit(STRIPE_EXPAND_READY, &sh->state);
 			set_bit(STRIPE_HANDLE, &sh->state);
 		}
-		release_stripe(sh);
+		list_add(&sh->lru, &stripes);
 	}
 	spin_lock_irq(&conf->device_lock);
-	conf->expand_progress = (sector_nr + i) * new_data_disks;
+	if (mddev->delta_disks < 0)
+		conf->reshape_progress -= reshape_sectors * new_data_disks;
+	else
+		conf->reshape_progress += reshape_sectors * new_data_disks;
 	spin_unlock_irq(&conf->device_lock);
 	/* Ok, those stripe are ready. We can start scheduling
 	 * reads on the source stripes.
@@ -3618,46 +3911,50 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
 	 * block on the destination stripes.
 	 */
 	first_sector =
-		raid5_compute_sector(sector_nr*(new_data_disks),
-				     raid_disks, data_disks,
-				     &dd_idx, &pd_idx, conf);
+		raid5_compute_sector(conf, stripe_addr*(new_data_disks),
+				     1, &dd_idx, NULL);
 	last_sector =
-		raid5_compute_sector((sector_nr+conf->chunk_size/512)
-				     *(new_data_disks) -1,
-				     raid_disks, data_disks,
-				     &dd_idx, &pd_idx, conf);
-	if (last_sector >= (mddev->size<<1))
-		last_sector = (mddev->size<<1)-1;
+		raid5_compute_sector(conf, ((stripe_addr+conf->chunk_size/512)
+					    *(new_data_disks) - 1),
+				     1, &dd_idx, NULL);
+	if (last_sector >= mddev->dev_sectors)
+		last_sector = mddev->dev_sectors - 1;
 	while (first_sector <= last_sector) {
-		pd_idx = stripe_to_pdidx(first_sector, conf,
-					 conf->previous_raid_disks);
-		sh = get_active_stripe(conf, first_sector,
-				       conf->previous_raid_disks, pd_idx, 0);
+		sh = get_active_stripe(conf, first_sector, 1, 0);
 		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
 		set_bit(STRIPE_HANDLE, &sh->state);
 		release_stripe(sh);
 		first_sector += STRIPE_SECTORS;
 	}
+	/* Now that the sources are clearly marked, we can release
+	 * the destination stripes
+	 */
+	while (!list_empty(&stripes)) {
+		sh = list_entry(stripes.next, struct stripe_head, lru);
+		list_del_init(&sh->lru);
+		release_stripe(sh);
+	}
 	/* If this takes us to the resync_max point where we have to pause,
 	 * then we need to write out the superblock.
 	 */
-	sector_nr += conf->chunk_size>>9;
+	sector_nr += reshape_sectors;
 	if (sector_nr >= mddev->resync_max) {
 		/* Cannot proceed until we've updated the superblock... */
 		wait_event(conf->wait_for_overlap,
 			   atomic_read(&conf->reshape_stripes) == 0);
-		mddev->reshape_position = conf->expand_progress;
+		mddev->reshape_position = conf->reshape_progress;
+		conf->reshape_checkpoint = jiffies;
 		set_bit(MD_CHANGE_DEVS, &mddev->flags);
 		md_wakeup_thread(mddev->thread);
 		wait_event(mddev->sb_wait,
 			   !test_bit(MD_CHANGE_DEVS, &mddev->flags)
 			   || kthread_should_stop());
 		spin_lock_irq(&conf->device_lock);
-		conf->expand_lo = mddev->reshape_position;
+		conf->reshape_safe = mddev->reshape_position;
 		spin_unlock_irq(&conf->device_lock);
 		wake_up(&conf->wait_for_overlap);
 	}
-	return conf->chunk_size>>9;
+	return reshape_sectors;
 }
 
 /* FIXME go_faster isn't used */
@@ -3665,9 +3962,7 @@ static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *ski
 {
 	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
 	struct stripe_head *sh;
-	int pd_idx;
-	int raid_disks = conf->raid_disks;
-	sector_t max_sector = mddev->size << 1;
+	sector_t max_sector = mddev->dev_sectors;
 	int sync_blocks;
 	int still_degraded = 0;
 	int i;
@@ -3675,6 +3970,7 @@ static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *ski
 	if (sector_nr >= max_sector) {
 		/* just being told to finish up .. nothing much to do */
 		unplug_slaves(mddev);
+
 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
 			end_reshape(conf);
 			return 0;
@@ -3705,7 +4001,7 @@ static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *ski
 	 */
 	if (mddev->degraded >= conf->max_degraded &&
 	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
-		sector_t rv = (mddev->size << 1) - sector_nr;
+		sector_t rv = mddev->dev_sectors - sector_nr;
 		*skipped = 1;
 		return rv;
 	}
@@ -3721,10 +4017,9 @@ static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *ski
 
 	bitmap_cond_end_sync(mddev->bitmap, sector_nr);
 
-	pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks);
-	sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1);
+	sh = get_active_stripe(conf, sector_nr, 0, 1);
 	if (sh == NULL) {
-		sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0);
+		sh = get_active_stripe(conf, sector_nr, 0, 0);
 		/* make sure we don't swamp the stripe cache if someone else
 		 * is trying to get access
 		 */
@@ -3766,19 +4061,15 @@ static int  retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
 	 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
 	 */
 	struct stripe_head *sh;
-	int dd_idx, pd_idx;
+	int dd_idx;
 	sector_t sector, logical_sector, last_sector;
 	int scnt = 0;
 	int remaining;
 	int handled = 0;
 
 	logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
-	sector = raid5_compute_sector(	logical_sector,
-					conf->raid_disks,
-					conf->raid_disks - conf->max_degraded,
-					&dd_idx,
-					&pd_idx,
-					conf);
+	sector = raid5_compute_sector(conf, logical_sector,
+				      0, &dd_idx, NULL);
 	last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);
 
 	for (; logical_sector < last_sector;
@@ -3790,7 +4081,7 @@ static int  retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
 			/* already done this stripe */
 			continue;
 
-		sh = get_active_stripe(conf, sector, conf->raid_disks, pd_idx, 1);
+		sh = get_active_stripe(conf, sector, 0, 1);
 
 		if (!sh) {
 			/* failed to get a stripe - must wait */
@@ -3992,89 +4283,69 @@ static struct attribute_group raid5_attrs_group = {
 	.attrs = raid5_attrs,
 };
 
-static int run(mddev_t *mddev)
+static sector_t
+raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks)
+{
+	raid5_conf_t *conf = mddev_to_conf(mddev);
+
+	if (!sectors)
+		sectors = mddev->dev_sectors;
+	if (!raid_disks) {
+		/* size is defined by the smallest of previous and new size */
+		if (conf->raid_disks < conf->previous_raid_disks)
+			raid_disks = conf->raid_disks;
+		else
+			raid_disks = conf->previous_raid_disks;
+	}
+
+	sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
+	sectors &= ~((sector_t)mddev->new_chunk/512 - 1);
+	return sectors * (raid_disks - conf->max_degraded);
+}
+
+static raid5_conf_t *setup_conf(mddev_t *mddev)
 {
 	raid5_conf_t *conf;
 	int raid_disk, memory;
 	mdk_rdev_t *rdev;
 	struct disk_info *disk;
-	int working_disks = 0;
 
-	if (mddev->level != 5 && mddev->level != 4 && mddev->level != 6) {
+	if (mddev->new_level != 5
+	    && mddev->new_level != 4
+	    && mddev->new_level != 6) {
 		printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n",
-		       mdname(mddev), mddev->level);
-		return -EIO;
+		       mdname(mddev), mddev->new_level);
+		return ERR_PTR(-EIO);
 	}
-
-	if (mddev->chunk_size < PAGE_SIZE) {
-		printk(KERN_ERR "md/raid5: chunk_size must be at least "
-		       "PAGE_SIZE but %d < %ld\n",
-		       mddev->chunk_size, PAGE_SIZE);
-		return -EINVAL;
+	if ((mddev->new_level == 5
+	     && !algorithm_valid_raid5(mddev->new_layout)) ||
+	    (mddev->new_level == 6
+	     && !algorithm_valid_raid6(mddev->new_layout))) {
+		printk(KERN_ERR "raid5: %s: layout %d not supported\n",
+		       mdname(mddev), mddev->new_layout);
+		return ERR_PTR(-EIO);
 	}
-
-	if (mddev->reshape_position != MaxSector) {
-		/* Check that we can continue the reshape.
-		 * Currently only disks can change, it must
-		 * increase, and we must be past the point where
-		 * a stripe over-writes itself
-		 */
-		sector_t here_new, here_old;
-		int old_disks;
-		int max_degraded = (mddev->level == 5 ? 1 : 2);
-
-		if (mddev->new_level != mddev->level ||
-		    mddev->new_layout != mddev->layout ||
-		    mddev->new_chunk != mddev->chunk_size) {
-			printk(KERN_ERR "raid5: %s: unsupported reshape "
-			       "required - aborting.\n",
-			       mdname(mddev));
-			return -EINVAL;
-		}
-		if (mddev->delta_disks <= 0) {
-			printk(KERN_ERR "raid5: %s: unsupported reshape "
-			       "(reduce disks) required - aborting.\n",
-			       mdname(mddev));
-			return -EINVAL;
-		}
-		old_disks = mddev->raid_disks - mddev->delta_disks;
-		/* reshape_position must be on a new-stripe boundary, and one
-		 * further up in new geometry must map after here in old
-		 * geometry.
-		 */
-		here_new = mddev->reshape_position;
-		if (sector_div(here_new, (mddev->chunk_size>>9)*
-			       (mddev->raid_disks - max_degraded))) {
-			printk(KERN_ERR "raid5: reshape_position not "
-			       "on a stripe boundary\n");
-			return -EINVAL;
-		}
-		/* here_new is the stripe we will write to */
-		here_old = mddev->reshape_position;
-		sector_div(here_old, (mddev->chunk_size>>9)*
-			   (old_disks-max_degraded));
-		/* here_old is the first stripe that we might need to read
-		 * from */
-		if (here_new >= here_old) {
-			/* Reading from the same stripe as writing to - bad */
-			printk(KERN_ERR "raid5: reshape_position too early for "
-			       "auto-recovery - aborting.\n");
-			return -EINVAL;
-		}
-		printk(KERN_INFO "raid5: reshape will continue\n");
-		/* OK, we should be able to continue; */
+	if (mddev->new_level == 6 && mddev->raid_disks < 4) {
+		printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
+		       mdname(mddev), mddev->raid_disks);
+		return ERR_PTR(-EINVAL);
 	}
 
+	if (!mddev->new_chunk || mddev->new_chunk % PAGE_SIZE) {
+		printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
+			mddev->new_chunk, mdname(mddev));
+		return ERR_PTR(-EINVAL);
+	}
 
-	mddev->private = kzalloc(sizeof (raid5_conf_t), GFP_KERNEL);
-	if ((conf = mddev->private) == NULL)
+	conf = kzalloc(sizeof(raid5_conf_t), GFP_KERNEL);
+	if (conf == NULL)
 		goto abort;
-	if (mddev->reshape_position == MaxSector) {
-		conf->previous_raid_disks = conf->raid_disks = mddev->raid_disks;
-	} else {
-		conf->raid_disks = mddev->raid_disks;
+
+	conf->raid_disks = mddev->raid_disks;
+	if (mddev->reshape_position == MaxSector)
+		conf->previous_raid_disks = mddev->raid_disks;
+	else
 		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
-	}
 
 	conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info),
 			      GFP_KERNEL);
@@ -4086,13 +4357,12 @@ static int run(mddev_t *mddev)
 	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
 		goto abort;
 
-	if (mddev->level == 6) {
+	if (mddev->new_level == 6) {
 		conf->spare_page = alloc_page(GFP_KERNEL);
 		if (!conf->spare_page)
 			goto abort;
 	}
 	spin_lock_init(&conf->device_lock);
-	mddev->queue->queue_lock = &conf->device_lock;
 	init_waitqueue_head(&conf->wait_for_stripe);
 	init_waitqueue_head(&conf->wait_for_overlap);
 	INIT_LIST_HEAD(&conf->handle_list);
@@ -4121,47 +4391,134 @@ static int run(mddev_t *mddev)
 			printk(KERN_INFO "raid5: device %s operational as raid"
 				" disk %d\n", bdevname(rdev->bdev,b),
 				raid_disk);
-			working_disks++;
 		} else
 			/* Cannot rely on bitmap to complete recovery */
 			conf->fullsync = 1;
 	}
 
-	/*
-	 * 0 for a fully functional array, 1 or 2 for a degraded array.
-	 */
-	mddev->degraded = conf->raid_disks - working_disks;
-	conf->mddev = mddev;
-	conf->chunk_size = mddev->chunk_size;
-	conf->level = mddev->level;
+	conf->chunk_size = mddev->new_chunk;
+	conf->level = mddev->new_level;
 	if (conf->level == 6)
 		conf->max_degraded = 2;
 	else
 		conf->max_degraded = 1;
-	conf->algorithm = mddev->layout;
+	conf->algorithm = mddev->new_layout;
 	conf->max_nr_stripes = NR_STRIPES;
-	conf->expand_progress = mddev->reshape_position;
-
-	/* device size must be a multiple of chunk size */
-	mddev->size &= ~(mddev->chunk_size/1024 -1);
-	mddev->resync_max_sectors = mddev->size << 1;
+	conf->reshape_progress = mddev->reshape_position;
+	if (conf->reshape_progress != MaxSector) {
+		conf->prev_chunk = mddev->chunk_size;
+		conf->prev_algo = mddev->layout;
+	}
 
-	if (conf->level == 6 && conf->raid_disks < 4) {
-		printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
-		       mdname(mddev), conf->raid_disks);
+	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
+		 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
+	if (grow_stripes(conf, conf->max_nr_stripes)) {
+		printk(KERN_ERR
+			"raid5: couldn't allocate %dkB for buffers\n", memory);
 		goto abort;
-	}
-	if (!conf->chunk_size || conf->chunk_size % 4) {
-		printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
-			conf->chunk_size, mdname(mddev));
+	} else
+		printk(KERN_INFO "raid5: allocated %dkB for %s\n",
+			memory, mdname(mddev));
+
+	conf->thread = md_register_thread(raid5d, mddev, "%s_raid5");
+	if (!conf->thread) {
+		printk(KERN_ERR
+		       "raid5: couldn't allocate thread for %s\n",
+		       mdname(mddev));
 		goto abort;
 	}
-	if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) {
-		printk(KERN_ERR 
-			"raid5: unsupported parity algorithm %d for %s\n",
-			conf->algorithm, mdname(mddev));
-		goto abort;
+
+	return conf;
+
+ abort:
+	if (conf) {
+		shrink_stripes(conf);
+		safe_put_page(conf->spare_page);
+		kfree(conf->disks);
+		kfree(conf->stripe_hashtbl);
+		kfree(conf);
+		return ERR_PTR(-EIO);
+	} else
+		return ERR_PTR(-ENOMEM);
+}
+
+static int run(mddev_t *mddev)
+{
+	raid5_conf_t *conf;
+	int working_disks = 0;
+	mdk_rdev_t *rdev;
+
+	if (mddev->reshape_position != MaxSector) {
+		/* Check that we can continue the reshape.
+		 * Currently only disks can change, it must
+		 * increase, and we must be past the point where
+		 * a stripe over-writes itself
+		 */
+		sector_t here_new, here_old;
+		int old_disks;
+		int max_degraded = (mddev->level == 6 ? 2 : 1);
+
+		if (mddev->new_level != mddev->level) {
+			printk(KERN_ERR "raid5: %s: unsupported reshape "
+			       "required - aborting.\n",
+			       mdname(mddev));
+			return -EINVAL;
+		}
+		old_disks = mddev->raid_disks - mddev->delta_disks;
+		/* reshape_position must be on a new-stripe boundary, and one
+		 * further up in new geometry must map after here in old
+		 * geometry.
+		 */
+		here_new = mddev->reshape_position;
+		if (sector_div(here_new, (mddev->new_chunk>>9)*
+			       (mddev->raid_disks - max_degraded))) {
+			printk(KERN_ERR "raid5: reshape_position not "
+			       "on a stripe boundary\n");
+			return -EINVAL;
+		}
+		/* here_new is the stripe we will write to */
+		here_old = mddev->reshape_position;
+		sector_div(here_old, (mddev->chunk_size>>9)*
+			   (old_disks-max_degraded));
+		/* here_old is the first stripe that we might need to read
+		 * from */
+		if (here_new >= here_old) {
+			/* Reading from the same stripe as writing to - bad */
+			printk(KERN_ERR "raid5: reshape_position too early for "
+			       "auto-recovery - aborting.\n");
+			return -EINVAL;
+		}
+		printk(KERN_INFO "raid5: reshape will continue\n");
+		/* OK, we should be able to continue; */
+	} else {
+		BUG_ON(mddev->level != mddev->new_level);
+		BUG_ON(mddev->layout != mddev->new_layout);
+		BUG_ON(mddev->chunk_size != mddev->new_chunk);
+		BUG_ON(mddev->delta_disks != 0);
 	}
+
+	if (mddev->private == NULL)
+		conf = setup_conf(mddev);
+	else
+		conf = mddev->private;
+
+	if (IS_ERR(conf))
+		return PTR_ERR(conf);
+
+	mddev->thread = conf->thread;
+	conf->thread = NULL;
+	mddev->private = conf;
+
+	/*
+	 * 0 for a fully functional array, 1 or 2 for a degraded array.
+	 */
+	list_for_each_entry(rdev, &mddev->disks, same_set)
+		if (rdev->raid_disk >= 0 &&
+		    test_bit(In_sync, &rdev->flags))
+			working_disks++;
+
+	mddev->degraded = conf->raid_disks - working_disks;
+
 	if (mddev->degraded > conf->max_degraded) {
 		printk(KERN_ERR "raid5: not enough operational devices for %s"
 			" (%d/%d failed)\n",
@@ -4169,6 +4526,10 @@ static int run(mddev_t *mddev)
 		goto abort;
 	}
 
+	/* device size must be a multiple of chunk size */
+	mddev->dev_sectors &= ~(mddev->chunk_size / 512 - 1);
+	mddev->resync_max_sectors = mddev->dev_sectors;
+
 	if (mddev->degraded > 0 &&
 	    mddev->recovery_cp != MaxSector) {
 		if (mddev->ok_start_degraded)
@@ -4184,43 +4545,22 @@ static int run(mddev_t *mddev)
 		}
 	}
 
-	{
-		mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5");
-		if (!mddev->thread) {
-			printk(KERN_ERR 
-				"raid5: couldn't allocate thread for %s\n",
-				mdname(mddev));
-			goto abort;
-		}
-	}
-	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
-		 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
-	if (grow_stripes(conf, conf->max_nr_stripes)) {
-		printk(KERN_ERR 
-			"raid5: couldn't allocate %dkB for buffers\n", memory);
-		shrink_stripes(conf);
-		md_unregister_thread(mddev->thread);
-		goto abort;
-	} else
-		printk(KERN_INFO "raid5: allocated %dkB for %s\n",
-			memory, mdname(mddev));
-
 	if (mddev->degraded == 0)
 		printk("raid5: raid level %d set %s active with %d out of %d"
-			" devices, algorithm %d\n", conf->level, mdname(mddev), 
-			mddev->raid_disks-mddev->degraded, mddev->raid_disks,
-			conf->algorithm);
+		       " devices, algorithm %d\n", conf->level, mdname(mddev),
+		       mddev->raid_disks-mddev->degraded, mddev->raid_disks,
+		       mddev->new_layout);
 	else
 		printk(KERN_ALERT "raid5: raid level %d set %s active with %d"
 			" out of %d devices, algorithm %d\n", conf->level,
 			mdname(mddev), mddev->raid_disks - mddev->degraded,
-			mddev->raid_disks, conf->algorithm);
+			mddev->raid_disks, mddev->new_layout);
 
 	print_raid5_conf(conf);
 
-	if (conf->expand_progress != MaxSector) {
+	if (conf->reshape_progress != MaxSector) {
 		printk("...ok start reshape thread\n");
-		conf->expand_lo = conf->expand_progress;
+		conf->reshape_safe = conf->reshape_progress;
 		atomic_set(&conf->reshape_stripes, 0);
 		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
 		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
@@ -4247,18 +4587,22 @@ static int run(mddev_t *mddev)
 		       "raid5: failed to create sysfs attributes for %s\n",
 		       mdname(mddev));
 
+	mddev->queue->queue_lock = &conf->device_lock;
+
 	mddev->queue->unplug_fn = raid5_unplug_device;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 	mddev->queue->backing_dev_info.congested_fn = raid5_congested;
 
-	mddev->array_sectors = 2 * mddev->size * (conf->previous_raid_disks -
-					    conf->max_degraded);
+	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
 
 	blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
 
 	return 0;
 abort:
+	md_unregister_thread(mddev->thread);
+	mddev->thread = NULL;
 	if (conf) {
+		shrink_stripes(conf);
 		print_raid5_conf(conf);
 		safe_put_page(conf->spare_page);
 		kfree(conf->disks);
@@ -4396,6 +4740,10 @@ static int raid5_remove_disk(mddev_t *mddev, int number)
 	print_raid5_conf(conf);
 	rdev = p->rdev;
 	if (rdev) {
+		if (number >= conf->raid_disks &&
+		    conf->reshape_progress == MaxSector)
+			clear_bit(In_sync, &rdev->flags);
+
 		if (test_bit(In_sync, &rdev->flags) ||
 		    atomic_read(&rdev->nr_pending)) {
 			err = -EBUSY;
@@ -4405,7 +4753,8 @@ static int raid5_remove_disk(mddev_t *mddev, int number)
 		 * isn't possible.
 		 */
 		if (!test_bit(Faulty, &rdev->flags) &&
-		    mddev->degraded <= conf->max_degraded) {
+		    mddev->degraded <= conf->max_degraded &&
+		    number < conf->raid_disks) {
 			err = -EBUSY;
 			goto abort;
 		}
@@ -4472,36 +4821,48 @@ static int raid5_resize(mddev_t *mddev, sector_t sectors)
 	 * any io in the removed space completes, but it hardly seems
 	 * worth it.
 	 */
-	raid5_conf_t *conf = mddev_to_conf(mddev);
-
 	sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
-	mddev->array_sectors = sectors * (mddev->raid_disks
-					  - conf->max_degraded);
+	md_set_array_sectors(mddev, raid5_size(mddev, sectors,
+					       mddev->raid_disks));
+	if (mddev->array_sectors >
+	    raid5_size(mddev, sectors, mddev->raid_disks))
+		return -EINVAL;
 	set_capacity(mddev->gendisk, mddev->array_sectors);
 	mddev->changed = 1;
-	if (sectors/2  > mddev->size && mddev->recovery_cp == MaxSector) {
-		mddev->recovery_cp = mddev->size << 1;
+	if (sectors > mddev->dev_sectors && mddev->recovery_cp == MaxSector) {
+		mddev->recovery_cp = mddev->dev_sectors;
 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 	}
-	mddev->size = sectors /2;
+	mddev->dev_sectors = sectors;
 	mddev->resync_max_sectors = sectors;
 	return 0;
 }
 
-#ifdef CONFIG_MD_RAID5_RESHAPE
 static int raid5_check_reshape(mddev_t *mddev)
 {
 	raid5_conf_t *conf = mddev_to_conf(mddev);
-	int err;
 
-	if (mddev->delta_disks < 0 ||
-	    mddev->new_level != mddev->level)
-		return -EINVAL; /* Cannot shrink array or change level yet */
-	if (mddev->delta_disks == 0)
-		return 0; /* nothing to do */
+	if (mddev->delta_disks == 0 &&
+	    mddev->new_layout == mddev->layout &&
+	    mddev->new_chunk == mddev->chunk_size)
+		return -EINVAL; /* nothing to do */
 	if (mddev->bitmap)
 		/* Cannot grow a bitmap yet */
 		return -EBUSY;
+	if (mddev->degraded > conf->max_degraded)
+		return -EINVAL;
+	if (mddev->delta_disks < 0) {
+		/* We might be able to shrink, but the devices must
+		 * be made bigger first.
+		 * For raid6, 4 is the minimum size.
+		 * Otherwise 2 is the minimum
+		 */
+		int min = 2;
+		if (mddev->level == 6)
+			min = 4;
+		if (mddev->raid_disks + mddev->delta_disks < min)
+			return -EINVAL;
+	}
 
 	/* Can only proceed if there are plenty of stripe_heads.
 	 * We need a minimum of one full stripe,, and for sensible progress
@@ -4514,18 +4875,12 @@ static int raid5_check_reshape(mddev_t *mddev)
 	if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes ||
 	    (mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) {
 		printk(KERN_WARNING "raid5: reshape: not enough stripes.  Needed %lu\n",
-		       (mddev->chunk_size / STRIPE_SIZE)*4);
+		       (max(mddev->chunk_size, mddev->new_chunk)
+			/ STRIPE_SIZE)*4);
 		return -ENOSPC;
 	}
 
-	err = resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
-	if (err)
-		return err;
-
-	if (mddev->degraded > conf->max_degraded)
-		return -EINVAL;
-	/* looks like we might be able to manage this */
-	return 0;
+	return resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
 }
 
 static int raid5_start_reshape(mddev_t *mddev)
@@ -4550,12 +4905,31 @@ static int raid5_start_reshape(mddev_t *mddev)
 		 */
 		return -EINVAL;
 
+	/* Refuse to reduce size of the array.  Any reductions in
+	 * array size must be through explicit setting of array_size
+	 * attribute.
+	 */
+	if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
+	    < mddev->array_sectors) {
+		printk(KERN_ERR "md: %s: array size must be reduced "
+		       "before number of disks\n", mdname(mddev));
+		return -EINVAL;
+	}
+
 	atomic_set(&conf->reshape_stripes, 0);
 	spin_lock_irq(&conf->device_lock);
 	conf->previous_raid_disks = conf->raid_disks;
 	conf->raid_disks += mddev->delta_disks;
-	conf->expand_progress = 0;
-	conf->expand_lo = 0;
+	conf->prev_chunk = conf->chunk_size;
+	conf->chunk_size = mddev->new_chunk;
+	conf->prev_algo = conf->algorithm;
+	conf->algorithm = mddev->new_layout;
+	if (mddev->delta_disks < 0)
+		conf->reshape_progress = raid5_size(mddev, 0, 0);
+	else
+		conf->reshape_progress = 0;
+	conf->reshape_safe = conf->reshape_progress;
+	conf->generation++;
 	spin_unlock_irq(&conf->device_lock);
 
 	/* Add some new drives, as many as will fit.
@@ -4580,9 +4954,12 @@ static int raid5_start_reshape(mddev_t *mddev)
 				break;
 		}
 
-	spin_lock_irqsave(&conf->device_lock, flags);
-	mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) - added_devices;
-	spin_unlock_irqrestore(&conf->device_lock, flags);
+	if (mddev->delta_disks > 0) {
+		spin_lock_irqsave(&conf->device_lock, flags);
+		mddev->degraded = (conf->raid_disks - conf->previous_raid_disks)
+			- added_devices;
+		spin_unlock_irqrestore(&conf->device_lock, flags);
+	}
 	mddev->raid_disks = conf->raid_disks;
 	mddev->reshape_position = 0;
 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
@@ -4597,52 +4974,86 @@ static int raid5_start_reshape(mddev_t *mddev)
 		mddev->recovery = 0;
 		spin_lock_irq(&conf->device_lock);
 		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
-		conf->expand_progress = MaxSector;
+		conf->reshape_progress = MaxSector;
 		spin_unlock_irq(&conf->device_lock);
 		return -EAGAIN;
 	}
+	conf->reshape_checkpoint = jiffies;
 	md_wakeup_thread(mddev->sync_thread);
 	md_new_event(mddev);
 	return 0;
 }
-#endif
 
+/* This is called from the reshape thread and should make any
+ * changes needed in 'conf'
+ */
 static void end_reshape(raid5_conf_t *conf)
 {
-	struct block_device *bdev;
 
 	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
-		conf->mddev->array_sectors = 2 * conf->mddev->size *
-			(conf->raid_disks - conf->max_degraded);
-		set_capacity(conf->mddev->gendisk, conf->mddev->array_sectors);
-		conf->mddev->changed = 1;
-
-		bdev = bdget_disk(conf->mddev->gendisk, 0);
-		if (bdev) {
-			mutex_lock(&bdev->bd_inode->i_mutex);
-			i_size_write(bdev->bd_inode,
-				     (loff_t)conf->mddev->array_sectors << 9);
-			mutex_unlock(&bdev->bd_inode->i_mutex);
-			bdput(bdev);
-		}
+
 		spin_lock_irq(&conf->device_lock);
-		conf->expand_progress = MaxSector;
+		conf->previous_raid_disks = conf->raid_disks;
+		conf->reshape_progress = MaxSector;
 		spin_unlock_irq(&conf->device_lock);
-		conf->mddev->reshape_position = MaxSector;
+		wake_up(&conf->wait_for_overlap);
 
 		/* read-ahead size must cover two whole stripes, which is
 		 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
 		 */
 		{
-			int data_disks = conf->previous_raid_disks - conf->max_degraded;
-			int stripe = data_disks *
-				(conf->mddev->chunk_size / PAGE_SIZE);
+			int data_disks = conf->raid_disks - conf->max_degraded;
+			int stripe = data_disks * (conf->chunk_size
+						   / PAGE_SIZE);
 			if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
 				conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
 		}
 	}
 }
 
+/* This is called from the raid5d thread with mddev_lock held.
+ * It makes config changes to the device.
+ */
+static void raid5_finish_reshape(mddev_t *mddev)
+{
+	struct block_device *bdev;
+	raid5_conf_t *conf = mddev_to_conf(mddev);
+
+	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
+
+		if (mddev->delta_disks > 0) {
+			md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
+			set_capacity(mddev->gendisk, mddev->array_sectors);
+			mddev->changed = 1;
+
+			bdev = bdget_disk(mddev->gendisk, 0);
+			if (bdev) {
+				mutex_lock(&bdev->bd_inode->i_mutex);
+				i_size_write(bdev->bd_inode,
+					     (loff_t)mddev->array_sectors << 9);
+				mutex_unlock(&bdev->bd_inode->i_mutex);
+				bdput(bdev);
+			}
+		} else {
+			int d;
+			mddev->degraded = conf->raid_disks;
+			for (d = 0; d < conf->raid_disks ; d++)
+				if (conf->disks[d].rdev &&
+				    test_bit(In_sync,
+					     &conf->disks[d].rdev->flags))
+					mddev->degraded--;
+			for (d = conf->raid_disks ;
+			     d < conf->raid_disks - mddev->delta_disks;
+			     d++)
+				raid5_remove_disk(mddev, d);
+		}
+		mddev->layout = conf->algorithm;
+		mddev->chunk_size = conf->chunk_size;
+		mddev->reshape_position = MaxSector;
+		mddev->delta_disks = 0;
+	}
+}
+
 static void raid5_quiesce(mddev_t *mddev, int state)
 {
 	raid5_conf_t *conf = mddev_to_conf(mddev);
@@ -4672,6 +5083,212 @@ static void raid5_quiesce(mddev_t *mddev, int state)
 	}
 }
 
+
+static void *raid5_takeover_raid1(mddev_t *mddev)
+{
+	int chunksect;
+
+	if (mddev->raid_disks != 2 ||
+	    mddev->degraded > 1)
+		return ERR_PTR(-EINVAL);
+
+	/* Should check if there are write-behind devices? */
+
+	chunksect = 64*2; /* 64K by default */
+
+	/* The array must be an exact multiple of chunksize */
+	while (chunksect && (mddev->array_sectors & (chunksect-1)))
+		chunksect >>= 1;
+
+	if ((chunksect<<9) < STRIPE_SIZE)
+		/* array size does not allow a suitable chunk size */
+		return ERR_PTR(-EINVAL);
+
+	mddev->new_level = 5;
+	mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
+	mddev->new_chunk = chunksect << 9;
+
+	return setup_conf(mddev);
+}
+
+static void *raid5_takeover_raid6(mddev_t *mddev)
+{
+	int new_layout;
+
+	switch (mddev->layout) {
+	case ALGORITHM_LEFT_ASYMMETRIC_6:
+		new_layout = ALGORITHM_LEFT_ASYMMETRIC;
+		break;
+	case ALGORITHM_RIGHT_ASYMMETRIC_6:
+		new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
+		break;
+	case ALGORITHM_LEFT_SYMMETRIC_6:
+		new_layout = ALGORITHM_LEFT_SYMMETRIC;
+		break;
+	case ALGORITHM_RIGHT_SYMMETRIC_6:
+		new_layout = ALGORITHM_RIGHT_SYMMETRIC;
+		break;
+	case ALGORITHM_PARITY_0_6:
+		new_layout = ALGORITHM_PARITY_0;
+		break;
+	case ALGORITHM_PARITY_N:
+		new_layout = ALGORITHM_PARITY_N;
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+	mddev->new_level = 5;
+	mddev->new_layout = new_layout;
+	mddev->delta_disks = -1;
+	mddev->raid_disks -= 1;
+	return setup_conf(mddev);
+}
+
+
+static int raid5_reconfig(mddev_t *mddev, int new_layout, int new_chunk)
+{
+	/* For a 2-drive array, the layout and chunk size can be changed
+	 * immediately as not restriping is needed.
+	 * For larger arrays we record the new value - after validation
+	 * to be used by a reshape pass.
+	 */
+	raid5_conf_t *conf = mddev_to_conf(mddev);
+
+	if (new_layout >= 0 && !algorithm_valid_raid5(new_layout))
+		return -EINVAL;
+	if (new_chunk > 0) {
+		if (new_chunk & (new_chunk-1))
+			/* not a power of 2 */
+			return -EINVAL;
+		if (new_chunk < PAGE_SIZE)
+			return -EINVAL;
+		if (mddev->array_sectors & ((new_chunk>>9)-1))
+			/* not factor of array size */
+			return -EINVAL;
+	}
+
+	/* They look valid */
+
+	if (mddev->raid_disks == 2) {
+
+		if (new_layout >= 0) {
+			conf->algorithm = new_layout;
+			mddev->layout = mddev->new_layout = new_layout;
+		}
+		if (new_chunk > 0) {
+			conf->chunk_size = new_chunk;
+			mddev->chunk_size = mddev->new_chunk = new_chunk;
+		}
+		set_bit(MD_CHANGE_DEVS, &mddev->flags);
+		md_wakeup_thread(mddev->thread);
+	} else {
+		if (new_layout >= 0)
+			mddev->new_layout = new_layout;
+		if (new_chunk > 0)
+			mddev->new_chunk = new_chunk;
+	}
+	return 0;
+}
+
+static int raid6_reconfig(mddev_t *mddev, int new_layout, int new_chunk)
+{
+	if (new_layout >= 0 && !algorithm_valid_raid6(new_layout))
+		return -EINVAL;
+	if (new_chunk > 0) {
+		if (new_chunk & (new_chunk-1))
+			/* not a power of 2 */
+			return -EINVAL;
+		if (new_chunk < PAGE_SIZE)
+			return -EINVAL;
+		if (mddev->array_sectors & ((new_chunk>>9)-1))
+			/* not factor of array size */
+			return -EINVAL;
+	}
+
+	/* They look valid */
+
+	if (new_layout >= 0)
+		mddev->new_layout = new_layout;
+	if (new_chunk > 0)
+		mddev->new_chunk = new_chunk;
+
+	return 0;
+}
+
+static void *raid5_takeover(mddev_t *mddev)
+{
+	/* raid5 can take over:
+	 *  raid0 - if all devices are the same - make it a raid4 layout
+	 *  raid1 - if there are two drives.  We need to know the chunk size
+	 *  raid4 - trivial - just use a raid4 layout.
+	 *  raid6 - Providing it is a *_6 layout
+	 *
+	 * For now, just do raid1
+	 */
+
+	if (mddev->level == 1)
+		return raid5_takeover_raid1(mddev);
+	if (mddev->level == 4) {
+		mddev->new_layout = ALGORITHM_PARITY_N;
+		mddev->new_level = 5;
+		return setup_conf(mddev);
+	}
+	if (mddev->level == 6)
+		return raid5_takeover_raid6(mddev);
+
+	return ERR_PTR(-EINVAL);
+}
+
+
+static struct mdk_personality raid5_personality;
+
+static void *raid6_takeover(mddev_t *mddev)
+{
+	/* Currently can only take over a raid5.  We map the
+	 * personality to an equivalent raid6 personality
+	 * with the Q block at the end.
+	 */
+	int new_layout;
+
+	if (mddev->pers != &raid5_personality)
+		return ERR_PTR(-EINVAL);
+	if (mddev->degraded > 1)
+		return ERR_PTR(-EINVAL);
+	if (mddev->raid_disks > 253)
+		return ERR_PTR(-EINVAL);
+	if (mddev->raid_disks < 3)
+		return ERR_PTR(-EINVAL);
+
+	switch (mddev->layout) {
+	case ALGORITHM_LEFT_ASYMMETRIC:
+		new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
+		break;
+	case ALGORITHM_RIGHT_ASYMMETRIC:
+		new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
+		break;
+	case ALGORITHM_LEFT_SYMMETRIC:
+		new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
+		break;
+	case ALGORITHM_RIGHT_SYMMETRIC:
+		new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
+		break;
+	case ALGORITHM_PARITY_0:
+		new_layout = ALGORITHM_PARITY_0_6;
+		break;
+	case ALGORITHM_PARITY_N:
+		new_layout = ALGORITHM_PARITY_N;
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+	mddev->new_level = 6;
+	mddev->new_layout = new_layout;
+	mddev->delta_disks = 1;
+	mddev->raid_disks += 1;
+	return setup_conf(mddev);
+}
+
+
 static struct mdk_personality raid6_personality =
 {
 	.name		= "raid6",
@@ -4687,11 +5304,13 @@ static struct mdk_personality raid6_personality =
 	.spare_active	= raid5_spare_active,
 	.sync_request	= sync_request,
 	.resize		= raid5_resize,
-#ifdef CONFIG_MD_RAID5_RESHAPE
+	.size		= raid5_size,
 	.check_reshape	= raid5_check_reshape,
 	.start_reshape  = raid5_start_reshape,
-#endif
+	.finish_reshape = raid5_finish_reshape,
 	.quiesce	= raid5_quiesce,
+	.takeover	= raid6_takeover,
+	.reconfig	= raid6_reconfig,
 };
 static struct mdk_personality raid5_personality =
 {
@@ -4708,11 +5327,13 @@ static struct mdk_personality raid5_personality =
 	.spare_active	= raid5_spare_active,
 	.sync_request	= sync_request,
 	.resize		= raid5_resize,
-#ifdef CONFIG_MD_RAID5_RESHAPE
+	.size		= raid5_size,
 	.check_reshape	= raid5_check_reshape,
 	.start_reshape  = raid5_start_reshape,
-#endif
+	.finish_reshape = raid5_finish_reshape,
 	.quiesce	= raid5_quiesce,
+	.takeover	= raid5_takeover,
+	.reconfig	= raid5_reconfig,
 };
 
 static struct mdk_personality raid4_personality =
@@ -4730,20 +5351,15 @@ static struct mdk_personality raid4_personality =
 	.spare_active	= raid5_spare_active,
 	.sync_request	= sync_request,
 	.resize		= raid5_resize,
-#ifdef CONFIG_MD_RAID5_RESHAPE
+	.size		= raid5_size,
 	.check_reshape	= raid5_check_reshape,
 	.start_reshape  = raid5_start_reshape,
-#endif
+	.finish_reshape = raid5_finish_reshape,
 	.quiesce	= raid5_quiesce,
 };
 
 static int __init raid5_init(void)
 {
-	int e;
-
-	e = raid6_select_algo();
-	if ( e )
-		return e;
 	register_md_personality(&raid6_personality);
 	register_md_personality(&raid5_personality);
 	register_md_personality(&raid4_personality);
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
new file mode 100644
index 0000000..52ba999
--- /dev/null
+++ b/drivers/md/raid5.h
@@ -0,0 +1,474 @@
+#ifndef _RAID5_H
+#define _RAID5_H
+
+#include <linux/raid/xor.h>
+
+/*
+ *
+ * Each stripe contains one buffer per disc.  Each buffer can be in
+ * one of a number of states stored in "flags".  Changes between
+ * these states happen *almost* exclusively under a per-stripe
+ * spinlock.  Some very specific changes can happen in bi_end_io, and
+ * these are not protected by the spin lock.
+ *
+ * The flag bits that are used to represent these states are:
+ *   R5_UPTODATE and R5_LOCKED
+ *
+ * State Empty == !UPTODATE, !LOCK
+ *        We have no data, and there is no active request
+ * State Want == !UPTODATE, LOCK
+ *        A read request is being submitted for this block
+ * State Dirty == UPTODATE, LOCK
+ *        Some new data is in this buffer, and it is being written out
+ * State Clean == UPTODATE, !LOCK
+ *        We have valid data which is the same as on disc
+ *
+ * The possible state transitions are:
+ *
+ *  Empty -> Want   - on read or write to get old data for  parity calc
+ *  Empty -> Dirty  - on compute_parity to satisfy write/sync request.(RECONSTRUCT_WRITE)
+ *  Empty -> Clean  - on compute_block when computing a block for failed drive
+ *  Want  -> Empty  - on failed read
+ *  Want  -> Clean  - on successful completion of read request
+ *  Dirty -> Clean  - on successful completion of write request
+ *  Dirty -> Clean  - on failed write
+ *  Clean -> Dirty  - on compute_parity to satisfy write/sync (RECONSTRUCT or RMW)
+ *
+ * The Want->Empty, Want->Clean, Dirty->Clean, transitions
+ * all happen in b_end_io at interrupt time.
+ * Each sets the Uptodate bit before releasing the Lock bit.
+ * This leaves one multi-stage transition:
+ *    Want->Dirty->Clean
+ * This is safe because thinking that a Clean buffer is actually dirty
+ * will at worst delay some action, and the stripe will be scheduled
+ * for attention after the transition is complete.
+ *
+ * There is one possibility that is not covered by these states.  That
+ * is if one drive has failed and there is a spare being rebuilt.  We
+ * can't distinguish between a clean block that has been generated
+ * from parity calculations, and a clean block that has been
+ * successfully written to the spare ( or to parity when resyncing).
+ * To distingush these states we have a stripe bit STRIPE_INSYNC that
+ * is set whenever a write is scheduled to the spare, or to the parity
+ * disc if there is no spare.  A sync request clears this bit, and
+ * when we find it set with no buffers locked, we know the sync is
+ * complete.
+ *
+ * Buffers for the md device that arrive via make_request are attached
+ * to the appropriate stripe in one of two lists linked on b_reqnext.
+ * One list (bh_read) for read requests, one (bh_write) for write.
+ * There should never be more than one buffer on the two lists
+ * together, but we are not guaranteed of that so we allow for more.
+ *
+ * If a buffer is on the read list when the associated cache buffer is
+ * Uptodate, the data is copied into the read buffer and it's b_end_io
+ * routine is called.  This may happen in the end_request routine only
+ * if the buffer has just successfully been read.  end_request should
+ * remove the buffers from the list and then set the Uptodate bit on
+ * the buffer.  Other threads may do this only if they first check
+ * that the Uptodate bit is set.  Once they have checked that they may
+ * take buffers off the read queue.
+ *
+ * When a buffer on the write list is committed for write it is copied
+ * into the cache buffer, which is then marked dirty, and moved onto a
+ * third list, the written list (bh_written).  Once both the parity
+ * block and the cached buffer are successfully written, any buffer on
+ * a written list can be returned with b_end_io.
+ *
+ * The write list and read list both act as fifos.  The read list is
+ * protected by the device_lock.  The write and written lists are
+ * protected by the stripe lock.  The device_lock, which can be
+ * claimed while the stipe lock is held, is only for list
+ * manipulations and will only be held for a very short time.  It can
+ * be claimed from interrupts.
+ *
+ *
+ * Stripes in the stripe cache can be on one of two lists (or on
+ * neither).  The "inactive_list" contains stripes which are not
+ * currently being used for any request.  They can freely be reused
+ * for another stripe.  The "handle_list" contains stripes that need
+ * to be handled in some way.  Both of these are fifo queues.  Each
+ * stripe is also (potentially) linked to a hash bucket in the hash
+ * table so that it can be found by sector number.  Stripes that are
+ * not hashed must be on the inactive_list, and will normally be at
+ * the front.  All stripes start life this way.
+ *
+ * The inactive_list, handle_list and hash bucket lists are all protected by the
+ * device_lock.
+ *  - stripes on the inactive_list never have their stripe_lock held.
+ *  - stripes have a reference counter. If count==0, they are on a list.
+ *  - If a stripe might need handling, STRIPE_HANDLE is set.
+ *  - When refcount reaches zero, then if STRIPE_HANDLE it is put on
+ *    handle_list else inactive_list
+ *
+ * This, combined with the fact that STRIPE_HANDLE is only ever
+ * cleared while a stripe has a non-zero count means that if the
+ * refcount is 0 and STRIPE_HANDLE is set, then it is on the
+ * handle_list and if recount is 0 and STRIPE_HANDLE is not set, then
+ * the stripe is on inactive_list.
+ *
+ * The possible transitions are:
+ *  activate an unhashed/inactive stripe (get_active_stripe())
+ *     lockdev check-hash unlink-stripe cnt++ clean-stripe hash-stripe unlockdev
+ *  activate a hashed, possibly active stripe (get_active_stripe())
+ *     lockdev check-hash if(!cnt++)unlink-stripe unlockdev
+ *  attach a request to an active stripe (add_stripe_bh())
+ *     lockdev attach-buffer unlockdev
+ *  handle a stripe (handle_stripe())
+ *     lockstripe clrSTRIPE_HANDLE ...
+ *		(lockdev check-buffers unlockdev) ..
+ *		change-state ..
+ *		record io/ops needed unlockstripe schedule io/ops
+ *  release an active stripe (release_stripe())
+ *     lockdev if (!--cnt) { if  STRIPE_HANDLE, add to handle_list else add to inactive-list } unlockdev
+ *
+ * The refcount counts each thread that have activated the stripe,
+ * plus raid5d if it is handling it, plus one for each active request
+ * on a cached buffer, and plus one if the stripe is undergoing stripe
+ * operations.
+ *
+ * Stripe operations are performed outside the stripe lock,
+ * the stripe operations are:
+ * -copying data between the stripe cache and user application buffers
+ * -computing blocks to save a disk access, or to recover a missing block
+ * -updating the parity on a write operation (reconstruct write and
+ *  read-modify-write)
+ * -checking parity correctness
+ * -running i/o to disk
+ * These operations are carried out by raid5_run_ops which uses the async_tx
+ * api to (optionally) offload operations to dedicated hardware engines.
+ * When requesting an operation handle_stripe sets the pending bit for the
+ * operation and increments the count.  raid5_run_ops is then run whenever
+ * the count is non-zero.
+ * There are some critical dependencies between the operations that prevent some
+ * from being requested while another is in flight.
+ * 1/ Parity check operations destroy the in cache version of the parity block,
+ *    so we prevent parity dependent operations like writes and compute_blocks
+ *    from starting while a check is in progress.  Some dma engines can perform
+ *    the check without damaging the parity block, in these cases the parity
+ *    block is re-marked up to date (assuming the check was successful) and is
+ *    not re-read from disk.
+ * 2/ When a write operation is requested we immediately lock the affected
+ *    blocks, and mark them as not up to date.  This causes new read requests
+ *    to be held off, as well as parity checks and compute block operations.
+ * 3/ Once a compute block operation has been requested handle_stripe treats
+ *    that block as if it is up to date.  raid5_run_ops guaruntees that any
+ *    operation that is dependent on the compute block result is initiated after
+ *    the compute block completes.
+ */
+
+/*
+ * Operations state - intermediate states that are visible outside of sh->lock
+ * In general _idle indicates nothing is running, _run indicates a data
+ * processing operation is active, and _result means the data processing result
+ * is stable and can be acted upon.  For simple operations like biofill and
+ * compute that only have an _idle and _run state they are indicated with
+ * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN)
+ */
+/**
+ * enum check_states - handles syncing / repairing a stripe
+ * @check_state_idle - check operations are quiesced
+ * @check_state_run - check operation is running
+ * @check_state_result - set outside lock when check result is valid
+ * @check_state_compute_run - check failed and we are repairing
+ * @check_state_compute_result - set outside lock when compute result is valid
+ */
+enum check_states {
+	check_state_idle = 0,
+	check_state_run, /* parity check */
+	check_state_check_result,
+	check_state_compute_run, /* parity repair */
+	check_state_compute_result,
+};
+
+/**
+ * enum reconstruct_states - handles writing or expanding a stripe
+ */
+enum reconstruct_states {
+	reconstruct_state_idle = 0,
+	reconstruct_state_prexor_drain_run,	/* prexor-write */
+	reconstruct_state_drain_run,		/* write */
+	reconstruct_state_run,			/* expand */
+	reconstruct_state_prexor_drain_result,
+	reconstruct_state_drain_result,
+	reconstruct_state_result,
+};
+
+struct stripe_head {
+	struct hlist_node	hash;
+	struct list_head	lru;	      /* inactive_list or handle_list */
+	struct raid5_private_data *raid_conf;
+	short			generation;	/* increments with every
+						 * reshape */
+	sector_t		sector;		/* sector of this row */
+	short			pd_idx;		/* parity disk index */
+	short			qd_idx;		/* 'Q' disk index for raid6 */
+	short			ddf_layout;/* use DDF ordering to calculate Q */
+	unsigned long		state;		/* state flags */
+	atomic_t		count;	      /* nr of active thread/requests */
+	spinlock_t		lock;
+	int			bm_seq;	/* sequence number for bitmap flushes */
+	int			disks;		/* disks in stripe */
+	enum check_states	check_state;
+	enum reconstruct_states reconstruct_state;
+	/* stripe_operations
+	 * @target - STRIPE_OP_COMPUTE_BLK target
+	 */
+	struct stripe_operations {
+		int		   target;
+		u32		   zero_sum_result;
+	} ops;
+	struct r5dev {
+		struct bio	req;
+		struct bio_vec	vec;
+		struct page	*page;
+		struct bio	*toread, *read, *towrite, *written;
+		sector_t	sector;			/* sector of this page */
+		unsigned long	flags;
+	} dev[1]; /* allocated with extra space depending of RAID geometry */
+};
+
+/* stripe_head_state - collects and tracks the dynamic state of a stripe_head
+ *     for handle_stripe.  It is only valid under spin_lock(sh->lock);
+ */
+struct stripe_head_state {
+	int syncing, expanding, expanded;
+	int locked, uptodate, to_read, to_write, failed, written;
+	int to_fill, compute, req_compute, non_overwrite;
+	int failed_num;
+	unsigned long ops_request;
+};
+
+/* r6_state - extra state data only relevant to r6 */
+struct r6_state {
+	int p_failed, q_failed, failed_num[2];
+};
+
+/* Flags */
+#define	R5_UPTODATE	0	/* page contains current data */
+#define	R5_LOCKED	1	/* IO has been submitted on "req" */
+#define	R5_OVERWRITE	2	/* towrite covers whole page */
+/* and some that are internal to handle_stripe */
+#define	R5_Insync	3	/* rdev && rdev->in_sync at start */
+#define	R5_Wantread	4	/* want to schedule a read */
+#define	R5_Wantwrite	5
+#define	R5_Overlap	7	/* There is a pending overlapping request on this block */
+#define	R5_ReadError	8	/* seen a read error here recently */
+#define	R5_ReWrite	9	/* have tried to over-write the readerror */
+
+#define	R5_Expanded	10	/* This block now has post-expand data */
+#define	R5_Wantcompute	11 /* compute_block in progress treat as
+				    * uptodate
+				    */
+#define	R5_Wantfill	12 /* dev->toread contains a bio that needs
+				    * filling
+				    */
+#define R5_Wantdrain	13 /* dev->towrite needs to be drained */
+/*
+ * Write method
+ */
+#define RECONSTRUCT_WRITE	1
+#define READ_MODIFY_WRITE	2
+/* not a write method, but a compute_parity mode */
+#define	CHECK_PARITY		3
+/* Additional compute_parity mode -- updates the parity w/o LOCKING */
+#define UPDATE_PARITY		4
+
+/*
+ * Stripe state
+ */
+#define STRIPE_HANDLE		2
+#define	STRIPE_SYNCING		3
+#define	STRIPE_INSYNC		4
+#define	STRIPE_PREREAD_ACTIVE	5
+#define	STRIPE_DELAYED		6
+#define	STRIPE_DEGRADED		7
+#define	STRIPE_BIT_DELAY	8
+#define	STRIPE_EXPANDING	9
+#define	STRIPE_EXPAND_SOURCE	10
+#define	STRIPE_EXPAND_READY	11
+#define	STRIPE_IO_STARTED	12 /* do not count towards 'bypass_count' */
+#define	STRIPE_FULL_WRITE	13 /* all blocks are set to be overwritten */
+#define	STRIPE_BIOFILL_RUN	14
+#define	STRIPE_COMPUTE_RUN	15
+/*
+ * Operation request flags
+ */
+#define STRIPE_OP_BIOFILL	0
+#define STRIPE_OP_COMPUTE_BLK	1
+#define STRIPE_OP_PREXOR	2
+#define STRIPE_OP_BIODRAIN	3
+#define STRIPE_OP_POSTXOR	4
+#define STRIPE_OP_CHECK	5
+
+/*
+ * Plugging:
+ *
+ * To improve write throughput, we need to delay the handling of some
+ * stripes until there has been a chance that several write requests
+ * for the one stripe have all been collected.
+ * In particular, any write request that would require pre-reading
+ * is put on a "delayed" queue until there are no stripes currently
+ * in a pre-read phase.  Further, if the "delayed" queue is empty when
+ * a stripe is put on it then we "plug" the queue and do not process it
+ * until an unplug call is made. (the unplug_io_fn() is called).
+ *
+ * When preread is initiated on a stripe, we set PREREAD_ACTIVE and add
+ * it to the count of prereading stripes.
+ * When write is initiated, or the stripe refcnt == 0 (just in case) we
+ * clear the PREREAD_ACTIVE flag and decrement the count
+ * Whenever the 'handle' queue is empty and the device is not plugged, we
+ * move any strips from delayed to handle and clear the DELAYED flag and set
+ * PREREAD_ACTIVE.
+ * In stripe_handle, if we find pre-reading is necessary, we do it if
+ * PREREAD_ACTIVE is set, else we set DELAYED which will send it to the delayed queue.
+ * HANDLE gets cleared if stripe_handle leave nothing locked.
+ */
+
+
+struct disk_info {
+	mdk_rdev_t	*rdev;
+};
+
+struct raid5_private_data {
+	struct hlist_head	*stripe_hashtbl;
+	mddev_t			*mddev;
+	struct disk_info	*spare;
+	int			chunk_size, level, algorithm;
+	int			max_degraded;
+	int			raid_disks;
+	int			max_nr_stripes;
+
+	/* reshape_progress is the leading edge of a 'reshape'
+	 * It has value MaxSector when no reshape is happening
+	 * If delta_disks < 0, it is the last sector we started work on,
+	 * else is it the next sector to work on.
+	 */
+	sector_t		reshape_progress;
+	/* reshape_safe is the trailing edge of a reshape.  We know that
+	 * before (or after) this address, all reshape has completed.
+	 */
+	sector_t		reshape_safe;
+	int			previous_raid_disks;
+	int			prev_chunk, prev_algo;
+	short			generation; /* increments with every reshape */
+	unsigned long		reshape_checkpoint; /* Time we last updated
+						     * metadata */
+
+	struct list_head	handle_list; /* stripes needing handling */
+	struct list_head	hold_list; /* preread ready stripes */
+	struct list_head	delayed_list; /* stripes that have plugged requests */
+	struct list_head	bitmap_list; /* stripes delaying awaiting bitmap update */
+	struct bio		*retry_read_aligned; /* currently retrying aligned bios   */
+	struct bio		*retry_read_aligned_list; /* aligned bios retry list  */
+	atomic_t		preread_active_stripes; /* stripes with scheduled io */
+	atomic_t		active_aligned_reads;
+	atomic_t		pending_full_writes; /* full write backlog */
+	int			bypass_count; /* bypassed prereads */
+	int			bypass_threshold; /* preread nice */
+	struct list_head	*last_hold; /* detect hold_list promotions */
+
+	atomic_t		reshape_stripes; /* stripes with pending writes for reshape */
+	/* unfortunately we need two cache names as we temporarily have
+	 * two caches.
+	 */
+	int			active_name;
+	char			cache_name[2][20];
+	struct kmem_cache		*slab_cache; /* for allocating stripes */
+
+	int			seq_flush, seq_write;
+	int			quiesce;
+
+	int			fullsync;  /* set to 1 if a full sync is needed,
+					    * (fresh device added).
+					    * Cleared when a sync completes.
+					    */
+
+	struct page 		*spare_page; /* Used when checking P/Q in raid6 */
+
+	/*
+	 * Free stripes pool
+	 */
+	atomic_t		active_stripes;
+	struct list_head	inactive_list;
+	wait_queue_head_t	wait_for_stripe;
+	wait_queue_head_t	wait_for_overlap;
+	int			inactive_blocked;	/* release of inactive stripes blocked,
+							 * waiting for 25% to be free
+							 */
+	int			pool_size; /* number of disks in stripeheads in pool */
+	spinlock_t		device_lock;
+	struct disk_info	*disks;
+
+	/* When taking over an array from a different personality, we store
+	 * the new thread here until we fully activate the array.
+	 */
+	struct mdk_thread_s	*thread;
+};
+
+typedef struct raid5_private_data raid5_conf_t;
+
+#define mddev_to_conf(mddev) ((raid5_conf_t *) mddev->private)
+
+/*
+ * Our supported algorithms
+ */
+#define ALGORITHM_LEFT_ASYMMETRIC	0 /* Rotating Parity N with Data Restart */
+#define ALGORITHM_RIGHT_ASYMMETRIC	1 /* Rotating Parity 0 with Data Restart */
+#define ALGORITHM_LEFT_SYMMETRIC	2 /* Rotating Parity N with Data Continuation */
+#define ALGORITHM_RIGHT_SYMMETRIC	3 /* Rotating Parity 0 with Data Continuation */
+
+/* Define non-rotating (raid4) algorithms.  These allow
+ * conversion of raid4 to raid5.
+ */
+#define ALGORITHM_PARITY_0		4 /* P or P,Q are initial devices */
+#define ALGORITHM_PARITY_N		5 /* P or P,Q are final devices. */
+
+/* DDF RAID6 layouts differ from md/raid6 layouts in two ways.
+ * Firstly, the exact positioning of the parity block is slightly
+ * different between the 'LEFT_*' modes of md and the "_N_*" modes
+ * of DDF.
+ * Secondly, or order of datablocks over which the Q syndrome is computed
+ * is different.
+ * Consequently we have different layouts for DDF/raid6 than md/raid6.
+ * These layouts are from the DDFv1.2 spec.
+ * Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but
+ * leaves RLQ=3 as 'Vendor Specific'
+ */
+
+#define ALGORITHM_ROTATING_ZERO_RESTART	8 /* DDF PRL=6 RLQ=1 */
+#define ALGORITHM_ROTATING_N_RESTART	9 /* DDF PRL=6 RLQ=2 */
+#define ALGORITHM_ROTATING_N_CONTINUE	10 /*DDF PRL=6 RLQ=3 */
+
+
+/* For every RAID5 algorithm we define a RAID6 algorithm
+ * with exactly the same layout for data and parity, and
+ * with the Q block always on the last device (N-1).
+ * This allows trivial conversion from RAID5 to RAID6
+ */
+#define ALGORITHM_LEFT_ASYMMETRIC_6	16
+#define ALGORITHM_RIGHT_ASYMMETRIC_6	17
+#define ALGORITHM_LEFT_SYMMETRIC_6	18
+#define ALGORITHM_RIGHT_SYMMETRIC_6	19
+#define ALGORITHM_PARITY_0_6		20
+#define ALGORITHM_PARITY_N_6		ALGORITHM_PARITY_N
+
+static inline int algorithm_valid_raid5(int layout)
+{
+	return (layout >= 0) &&
+		(layout <= 5);
+}
+static inline int algorithm_valid_raid6(int layout)
+{
+	return (layout >= 0 && layout <= 5)
+		||
+		(layout == 8 || layout == 10)
+		||
+		(layout >= 16 && layout <= 20);
+}
+
+static inline int algorithm_is_DDF(int layout)
+{
+	return layout >= 8 && layout <= 10;
+}
+#endif
diff --git a/drivers/md/raid6.h b/drivers/md/raid6.h
deleted file mode 100644
index 98dcde8..0000000
--- a/drivers/md/raid6.h
+++ /dev/null
@@ -1,130 +0,0 @@
-/* -*- linux-c -*- ------------------------------------------------------- *
- *
- *   Copyright 2003 H. Peter Anvin - All Rights Reserved
- *
- *   This program is free software; you can redistribute it and/or modify
- *   it under the terms of the GNU General Public License as published by
- *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
- *   Bostom MA 02111-1307, USA; either version 2 of the License, or
- *   (at your option) any later version; incorporated herein by reference.
- *
- * ----------------------------------------------------------------------- */
-
-#ifndef LINUX_RAID_RAID6_H
-#define LINUX_RAID_RAID6_H
-
-#ifdef __KERNEL__
-
-/* Set to 1 to use kernel-wide empty_zero_page */
-#define RAID6_USE_EMPTY_ZERO_PAGE 0
-
-#include <linux/raid/md.h>
-#include <linux/raid/raid5.h>
-
-typedef raid5_conf_t raid6_conf_t; /* Same configuration */
-
-/* Additional compute_parity mode -- updates the parity w/o LOCKING */
-#define UPDATE_PARITY	4
-
-/* We need a pre-zeroed page... if we don't want to use the kernel-provided
-   one define it here */
-#if RAID6_USE_EMPTY_ZERO_PAGE
-# define raid6_empty_zero_page empty_zero_page
-#else
-extern const char raid6_empty_zero_page[PAGE_SIZE];
-#endif
-
-#else /* ! __KERNEL__ */
-/* Used for testing in user space */
-
-#include <errno.h>
-#include <inttypes.h>
-#include <limits.h>
-#include <stddef.h>
-#include <sys/mman.h>
-#include <sys/types.h>
-
-/* Not standard, but glibc defines it */
-#define BITS_PER_LONG __WORDSIZE
-
-typedef uint8_t  u8;
-typedef uint16_t u16;
-typedef uint32_t u32;
-typedef uint64_t u64;
-
-#ifndef PAGE_SIZE
-# define PAGE_SIZE 4096
-#endif
-extern const char raid6_empty_zero_page[PAGE_SIZE];
-
-#define __init
-#define __exit
-#define __attribute_const__ __attribute__((const))
-#define noinline __attribute__((noinline))
-
-#define preempt_enable()
-#define preempt_disable()
-#define cpu_has_feature(x) 1
-#define enable_kernel_altivec()
-#define disable_kernel_altivec()
-
-#endif /* __KERNEL__ */
-
-/* Routine choices */
-struct raid6_calls {
-	void (*gen_syndrome)(int, size_t, void **);
-	int  (*valid)(void);	/* Returns 1 if this routine set is usable */
-	const char *name;	/* Name of this routine set */
-	int prefer;		/* Has special performance attribute */
-};
-
-/* Selected algorithm */
-extern struct raid6_calls raid6_call;
-
-/* Algorithm list */
-extern const struct raid6_calls * const raid6_algos[];
-int raid6_select_algo(void);
-
-/* Return values from chk_syndrome */
-#define RAID6_OK	0
-#define RAID6_P_BAD	1
-#define RAID6_Q_BAD	2
-#define RAID6_PQ_BAD	3
-
-/* Galois field tables */
-extern const u8 raid6_gfmul[256][256] __attribute__((aligned(256)));
-extern const u8 raid6_gfexp[256]      __attribute__((aligned(256)));
-extern const u8 raid6_gfinv[256]      __attribute__((aligned(256)));
-extern const u8 raid6_gfexi[256]      __attribute__((aligned(256)));
-
-/* Recovery routines */
-void raid6_2data_recov(int disks, size_t bytes, int faila, int failb, void **ptrs);
-void raid6_datap_recov(int disks, size_t bytes, int faila, void **ptrs);
-void raid6_dual_recov(int disks, size_t bytes, int faila, int failb, void **ptrs);
-
-/* Some definitions to allow code to be compiled for testing in userspace */
-#ifndef __KERNEL__
-
-# define jiffies	raid6_jiffies()
-# define printk 	printf
-# define GFP_KERNEL	0
-# define __get_free_pages(x,y)	((unsigned long)mmap(NULL, PAGE_SIZE << (y), PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0))
-# define free_pages(x,y)	munmap((void *)(x), (y)*PAGE_SIZE)
-
-static inline void cpu_relax(void)
-{
-	/* Nothing */
-}
-
-#undef  HZ
-#define HZ 1000
-static inline uint32_t raid6_jiffies(void)
-{
-	struct timeval tv;
-	gettimeofday(&tv, NULL);
-	return tv.tv_sec*1000 + tv.tv_usec/1000;
-}
-
-#endif /* ! __KERNEL__ */
-
-#endif /* LINUX_RAID_RAID6_H */
diff --git a/drivers/md/raid6algos.c b/drivers/md/raid6algos.c
index 21987e3..866215a 100644
--- a/drivers/md/raid6algos.c
+++ b/drivers/md/raid6algos.c
@@ -5,7 +5,7 @@
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
- *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
  *   (at your option) any later version; incorporated herein by reference.
  *
  * ----------------------------------------------------------------------- */
@@ -16,13 +16,20 @@
  * Algorithm list and algorithm selection for RAID-6
  */
 
-#include "raid6.h"
+#include <linux/raid/pq.h>
 #ifndef __KERNEL__
 #include <sys/mman.h>
 #include <stdio.h>
+#else
+#if !RAID6_USE_EMPTY_ZERO_PAGE
+/* In .bss so it's zeroed */
+const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
+EXPORT_SYMBOL(raid6_empty_zero_page);
+#endif
 #endif
 
 struct raid6_calls raid6_call;
+EXPORT_SYMBOL_GPL(raid6_call);
 
 /* Various routine sets */
 extern const struct raid6_calls raid6_intx1;
@@ -79,6 +86,7 @@ const struct raid6_calls * const raid6_algos[] = {
 #else
 /* Need more time to be stable in userspace */
 #define RAID6_TIME_JIFFIES_LG2	9
+#define time_before(x, y) ((x) < (y))
 #endif
 
 /* Try to pick the best algorithm */
@@ -152,3 +160,12 @@ int __init raid6_select_algo(void)
 
 	return best ? 0 : -EINVAL;
 }
+
+static void raid6_exit(void)
+{
+	do { } while (0);
+}
+
+subsys_initcall(raid6_select_algo);
+module_exit(raid6_exit);
+MODULE_LICENSE("GPL");
diff --git a/drivers/md/raid6altivec.uc b/drivers/md/raid6altivec.uc
index b9afd35..699dfee 100644
--- a/drivers/md/raid6altivec.uc
+++ b/drivers/md/raid6altivec.uc
@@ -5,7 +5,7 @@
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
- *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
  *   (at your option) any later version; incorporated herein by reference.
  *
  * ----------------------------------------------------------------------- */
@@ -22,7 +22,7 @@
  * bracked this with preempt_disable/enable or in a lock)
  */
 
-#include "raid6.h"
+#include <linux/raid/pq.h>
 
 #ifdef CONFIG_ALTIVEC
 
diff --git a/drivers/md/raid6int.uc b/drivers/md/raid6int.uc
index ad004ce..f9bf9cb 100644
--- a/drivers/md/raid6int.uc
+++ b/drivers/md/raid6int.uc
@@ -5,7 +5,7 @@
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
- *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
  *   (at your option) any later version; incorporated herein by reference.
  *
  * ----------------------------------------------------------------------- */
@@ -18,7 +18,7 @@
  * This file is postprocessed using unroll.pl
  */
 
-#include "raid6.h"
+#include <linux/raid/pq.h>
 
 /*
  * This is the C data type to use
diff --git a/drivers/md/raid6mmx.c b/drivers/md/raid6mmx.c
index d4e4a1b..e7f6c13 100644
--- a/drivers/md/raid6mmx.c
+++ b/drivers/md/raid6mmx.c
@@ -5,7 +5,7 @@
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
- *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
  *   (at your option) any later version; incorporated herein by reference.
  *
  * ----------------------------------------------------------------------- */
@@ -18,7 +18,7 @@
 
 #if defined(__i386__) && !defined(__arch_um__)
 
-#include "raid6.h"
+#include <linux/raid/pq.h>
 #include "raid6x86.h"
 
 /* Shared with raid6sse1.c */
diff --git a/drivers/md/raid6recov.c b/drivers/md/raid6recov.c
index a8c4d94..2609f00 100644
--- a/drivers/md/raid6recov.c
+++ b/drivers/md/raid6recov.c
@@ -5,7 +5,7 @@
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
- *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
  *   (at your option) any later version; incorporated herein by reference.
  *
  * ----------------------------------------------------------------------- */
@@ -18,7 +18,7 @@
  * the syndrome.)
  */
 
-#include "raid6.h"
+#include <linux/raid/pq.h>
 
 /* Recover two failed data blocks. */
 void raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
@@ -63,9 +63,7 @@ void raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
 		p++; q++;
 	}
 }
-
-
-
+EXPORT_SYMBOL_GPL(raid6_2data_recov);
 
 /* Recover failure of one data block plus the P block */
 void raid6_datap_recov(int disks, size_t bytes, int faila, void **ptrs)
@@ -97,9 +95,10 @@ void raid6_datap_recov(int disks, size_t bytes, int faila, void **ptrs)
 		q++; dq++;
 	}
 }
+EXPORT_SYMBOL_GPL(raid6_datap_recov);
 
-
-#ifndef __KERNEL__		/* Testing only */
+#ifndef __KERNEL__
+/* Testing only */
 
 /* Recover two failed blocks. */
 void raid6_dual_recov(int disks, size_t bytes, int faila, int failb, void **ptrs)
diff --git a/drivers/md/raid6sse1.c b/drivers/md/raid6sse1.c
index 0666237..b274dd5 100644
--- a/drivers/md/raid6sse1.c
+++ b/drivers/md/raid6sse1.c
@@ -5,7 +5,7 @@
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
- *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
  *   (at your option) any later version; incorporated herein by reference.
  *
  * ----------------------------------------------------------------------- */
@@ -23,7 +23,7 @@
 
 #if defined(__i386__) && !defined(__arch_um__)
 
-#include "raid6.h"
+#include <linux/raid/pq.h>
 #include "raid6x86.h"
 
 /* Defined in raid6mmx.c */
diff --git a/drivers/md/raid6sse2.c b/drivers/md/raid6sse2.c
index b034ad8..6ed6c6c 100644
--- a/drivers/md/raid6sse2.c
+++ b/drivers/md/raid6sse2.c
@@ -5,7 +5,7 @@
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
- *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
  *   (at your option) any later version; incorporated herein by reference.
  *
  * ----------------------------------------------------------------------- */
@@ -19,7 +19,7 @@
 
 #if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__)
 
-#include "raid6.h"
+#include <linux/raid/pq.h>
 #include "raid6x86.h"
 
 static const struct raid6_sse_constants {
diff --git a/drivers/md/raid6test/Makefile b/drivers/md/raid6test/Makefile
index 78e0396..58ffdf4 100644
--- a/drivers/md/raid6test/Makefile
+++ b/drivers/md/raid6test/Makefile
@@ -5,7 +5,7 @@
 
 CC	 = gcc
 OPTFLAGS = -O2			# Adjust as desired
-CFLAGS	 = -I.. -g $(OPTFLAGS)
+CFLAGS	 = -I.. -I ../../../include -g $(OPTFLAGS)
 LD	 = ld
 PERL	 = perl
 AR	 = ar
diff --git a/drivers/md/raid6test/test.c b/drivers/md/raid6test/test.c
index 559cc41..7a93031 100644
--- a/drivers/md/raid6test/test.c
+++ b/drivers/md/raid6test/test.c
@@ -17,7 +17,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
-#include "raid6.h"
+#include <linux/raid/pq.h>
 
 #define NDISKS		16	/* Including P and Q */
 
diff --git a/drivers/md/raid6x86.h b/drivers/md/raid6x86.h
index 99fea7a..4c22c15 100644
--- a/drivers/md/raid6x86.h
+++ b/drivers/md/raid6x86.h
@@ -5,7 +5,7 @@
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
- *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
  *   (at your option) any later version; incorporated herein by reference.
  *
  * ----------------------------------------------------------------------- */