Merge /spare/repo/linux-2.6/

12 files changed, 2234 insertions, 239 deletions

diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 90de9c146a5f..d3efedf6a6ad 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -7,6 +7,7 @@ dm-mod-objs	:= dm.o dm-table.o dm-target.o dm-linear.o dm-stripe.o \
 dm-multipath-objs := dm-hw-handler.o dm-path-selector.o dm-mpath.o
 dm-snapshot-objs := dm-snap.o dm-exception-store.o
 dm-mirror-objs  := dm-log.o dm-raid1.o
+md-mod-objs     := md.o bitmap.o
 raid6-objs      := raid6main.o raid6algos.o raid6recov.o raid6tables.o \
                    raid6int1.o raid6int2.o raid6int4.o \
                    raid6int8.o raid6int16.o raid6int32.o \
@@ -28,7 +29,7 @@ obj-$(CONFIG_MD_RAID5)		+= raid5.o xor.o
 obj-$(CONFIG_MD_RAID6)          += raid6.o xor.o
 obj-$(CONFIG_MD_MULTIPATH)      += multipath.o
 obj-$(CONFIG_MD_FAULTY)         += faulty.o
-obj-$(CONFIG_BLK_DEV_MD)        += md.o
+obj-$(CONFIG_BLK_DEV_MD)        += md-mod.o
 obj-$(CONFIG_BLK_DEV_DM)        += dm-mod.o
 obj-$(CONFIG_DM_CRYPT)          += dm-crypt.o
 obj-$(CONFIG_DM_MULTIPATH)      += dm-multipath.o dm-round-robin.o
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
new file mode 100644
index 000000000000..95980ad6b27b
--- /dev/null
+++ b/drivers/md/bitmap.c
@@ -0,0 +1,1586 @@
+/*
+ * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
+ *
+ * bitmap_create  - sets up the bitmap structure
+ * bitmap_destroy - destroys the bitmap structure
+ *
+ * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
+ * - added disk storage for bitmap
+ * - changes to allow various bitmap chunk sizes
+ * - added bitmap daemon (to asynchronously clear bitmap bits from disk)
+ */
+
+/*
+ * Still to do:
+ *
+ * flush after percent set rather than just time based. (maybe both).
+ * wait if count gets too high, wake when it drops to half.
+ * allow bitmap to be mirrored with superblock (before or after...)
+ * allow hot-add to re-instate a current device.
+ * allow hot-add of bitmap after quiessing device
+ */
+
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/config.h>
+#include <linux/timer.h>
+#include <linux/sched.h>
+#include <linux/list.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+#include <linux/buffer_head.h>
+#include <linux/raid/md.h>
+#include <linux/raid/bitmap.h>
+
+/* debug macros */
+
+#define DEBUG 0
+
+#if DEBUG
+/* these are for debugging purposes only! */
+
+/* define one and only one of these */
+#define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
+#define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
+#define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
+#define INJECT_FAULTS_4 0 /* undef */
+#define INJECT_FAULTS_5 0 /* undef */
+#define INJECT_FAULTS_6 0
+
+/* if these are defined, the driver will fail! debug only */
+#define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
+#define INJECT_FATAL_FAULT_2 0 /* undef */
+#define INJECT_FATAL_FAULT_3 0 /* undef */
+#endif
+
+//#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
+#define DPRINTK(x...) do { } while(0)
+
+#ifndef PRINTK
+#  if DEBUG > 0
+#    define PRINTK(x...) printk(KERN_DEBUG x)
+#  else
+#    define PRINTK(x...)
+#  endif
+#endif
+
+static inline char * bmname(struct bitmap *bitmap)
+{
+        return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
+}
+
+
+/*
+ * test if the bitmap is active
+ */
+int bitmap_active(struct bitmap *bitmap)
+{
+        unsigned long flags;
+        int res = 0;
+
+        if (!bitmap)
+                return res;
+        spin_lock_irqsave(&bitmap->lock, flags);
+        res = bitmap->flags & BITMAP_ACTIVE;
+        spin_unlock_irqrestore(&bitmap->lock, flags);
+        return res;
+}
+
+#define WRITE_POOL_SIZE 256
+/* mempool for queueing pending writes on the bitmap file */
+static void *write_pool_alloc(unsigned int gfp_flags, void *data)
+{
+        return kmalloc(sizeof(struct page_list), gfp_flags);
+}
+
+static void write_pool_free(void *ptr, void *data)
+{
+        kfree(ptr);
+}
+
+/*
+ * just a placeholder - calls kmalloc for bitmap pages
+ */
+static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
+{
+        unsigned char *page;
+
+#if INJECT_FAULTS_1
+        page = NULL;
+#else
+        page = kmalloc(PAGE_SIZE, GFP_NOIO);
+#endif
+        if (!page)
+                printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
+        else
+                PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
+                        bmname(bitmap), page);
+        return page;
+}
+
+/*
+ * for now just a placeholder -- just calls kfree for bitmap pages
+ */
+static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
+{
+        PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
+        kfree(page);
+}
+
+/*
+ * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
+ *
+ * 1) check to see if this page is allocated, if it's not then try to alloc
+ * 2) if the alloc fails, set the page's hijacked flag so we'll use the
+ *    page pointer directly as a counter
+ *
+ * if we find our page, we increment the page's refcount so that it stays
+ * allocated while we're using it
+ */
+static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
+{
+        unsigned char *mappage;
+
+        if (page >= bitmap->pages) {
+                printk(KERN_ALERT
+                        "%s: invalid bitmap page request: %lu (> %lu)\n",
+                        bmname(bitmap), page, bitmap->pages-1);
+                return -EINVAL;
+        }
+
+
+        if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
+                return 0;
+
+        if (bitmap->bp[page].map) /* page is already allocated, just return */
+                return 0;
+
+        if (!create)
+                return -ENOENT;
+
+        spin_unlock_irq(&bitmap->lock);
+
+        /* this page has not been allocated yet */
+
+        if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
+                PRINTK("%s: bitmap map page allocation failed, hijacking\n",
+                        bmname(bitmap));
+                /* failed - set the hijacked flag so that we can use the
+                 * pointer as a counter */
+                spin_lock_irq(&bitmap->lock);
+                if (!bitmap->bp[page].map)
+                        bitmap->bp[page].hijacked = 1;
+                goto out;
+        }
+
+        /* got a page */
+
+        spin_lock_irq(&bitmap->lock);
+
+        /* recheck the page */
+
+        if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
+                /* somebody beat us to getting the page */
+                bitmap_free_page(bitmap, mappage);
+                return 0;
+        }
+
+        /* no page was in place and we have one, so install it */
+
+        memset(mappage, 0, PAGE_SIZE);
+        bitmap->bp[page].map = mappage;
+        bitmap->missing_pages--;
+out:
+        return 0;
+}
+
+
+/* if page is completely empty, put it back on the free list, or dealloc it */
+/* if page was hijacked, unmark the flag so it might get alloced next time */
+/* Note: lock should be held when calling this */
+static inline void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
+{
+        char *ptr;
+
+        if (bitmap->bp[page].count) /* page is still busy */
+                return;
+
+        /* page is no longer in use, it can be released */
+
+        if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
+                bitmap->bp[page].hijacked = 0;
+                bitmap->bp[page].map = NULL;
+                return;
+        }
+
+        /* normal case, free the page */
+
+#if 0
+/* actually ... let's not.  We will probably need the page again exactly when
+ * memory is tight and we are flusing to disk
+ */
+        return;
+#else
+        ptr = bitmap->bp[page].map;
+        bitmap->bp[page].map = NULL;
+        bitmap->missing_pages++;
+        bitmap_free_page(bitmap, ptr);
+        return;
+#endif
+}
+
+
+/*
+ * bitmap file handling - read and write the bitmap file and its superblock
+ */
+
+/* copy the pathname of a file to a buffer */
+char *file_path(struct file *file, char *buf, int count)
+{
+        struct dentry *d;
+        struct vfsmount *v;
+
+        if (!buf)
+                return NULL;
+
+        d = file->f_dentry;
+        v = file->f_vfsmnt;
+
+        buf = d_path(d, v, buf, count);
+
+        return IS_ERR(buf) ? NULL : buf;
+}
+
+/*
+ * basic page I/O operations
+ */
+
+/* IO operations when bitmap is stored near all superblocks */
+static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
+{
+        /* choose a good rdev and read the page from there */
+
+        mdk_rdev_t *rdev;
+        struct list_head *tmp;
+        struct page *page = alloc_page(GFP_KERNEL);
+        sector_t target;
+
+        if (!page)
+                return ERR_PTR(-ENOMEM);
+        do {
+                ITERATE_RDEV(mddev, rdev, tmp)
+                        if (rdev->in_sync && !rdev->faulty)
+                                goto found;
+                return ERR_PTR(-EIO);
+
+        found:
+                target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
+
+        } while (!sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ));
+
+        page->index = index;
+        return page;
+}
+
+static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
+{
+        mdk_rdev_t *rdev;
+        struct list_head *tmp;
+
+        ITERATE_RDEV(mddev, rdev, tmp)
+                if (rdev->in_sync && !rdev->faulty)
+                        md_super_write(mddev, rdev,
+                                       (rdev->sb_offset<<1) + offset
+                                       + page->index * (PAGE_SIZE/512),
+                                       PAGE_SIZE,
+                                       page);
+
+        if (wait)
+                wait_event(mddev->sb_wait, atomic_read(&mddev->pending_writes)==0);
+        return 0;
+}
+
+/*
+ * write out a page to a file
+ */
+static int write_page(struct bitmap *bitmap, struct page *page, int wait)
+{
+        int ret = -ENOMEM;
+
+        if (bitmap->file == NULL)
+                return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
+
+        if (wait)
+                lock_page(page);
+        else {
+                if (TestSetPageLocked(page))
+                        return -EAGAIN; /* already locked */
+                if (PageWriteback(page)) {
+                        unlock_page(page);
+                        return -EAGAIN;
+                }
+        }
+
+        ret = page->mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
+        if (!ret)
+                ret = page->mapping->a_ops->commit_write(NULL, page, 0,
+                        PAGE_SIZE);
+        if (ret) {
+                unlock_page(page);
+                return ret;
+        }
+
+        set_page_dirty(page); /* force it to be written out */
+
+        if (!wait) {
+                /* add to list to be waited for by daemon */
+                struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
+                item->page = page;
+                page_cache_get(page);
+                spin_lock(&bitmap->write_lock);
+                list_add(&item->list, &bitmap->complete_pages);
+                spin_unlock(&bitmap->write_lock);
+                md_wakeup_thread(bitmap->writeback_daemon);
+        }
+        return write_one_page(page, wait);
+}
+
+/* read a page from a file, pinning it into cache, and return bytes_read */
+static struct page *read_page(struct file *file, unsigned long index,
+                                        unsigned long *bytes_read)
+{
+        struct inode *inode = file->f_mapping->host;
+        struct page *page = NULL;
+        loff_t isize = i_size_read(inode);
+        unsigned long end_index = isize >> PAGE_CACHE_SHIFT;
+
+        PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_CACHE_SIZE,
+                        (unsigned long long)index << PAGE_CACHE_SHIFT);
+
+        page = read_cache_page(inode->i_mapping, index,
+                        (filler_t *)inode->i_mapping->a_ops->readpage, file);
+        if (IS_ERR(page))
+                goto out;
+        wait_on_page_locked(page);
+        if (!PageUptodate(page) || PageError(page)) {
+                page_cache_release(page);
+                page = ERR_PTR(-EIO);
+                goto out;
+        }
+
+        if (index > end_index) /* we have read beyond EOF */
+                *bytes_read = 0;
+        else if (index == end_index) /* possible short read */
+                *bytes_read = isize & ~PAGE_CACHE_MASK;
+        else
+                *bytes_read = PAGE_CACHE_SIZE; /* got a full page */
+out:
+        if (IS_ERR(page))
+                printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
+                        (int)PAGE_CACHE_SIZE,
+                        (unsigned long long)index << PAGE_CACHE_SHIFT,
+                        PTR_ERR(page));
+        return page;
+}
+
+/*
+ * bitmap file superblock operations
+ */
+
+/* update the event counter and sync the superblock to disk */
+int bitmap_update_sb(struct bitmap *bitmap)
+{
+        bitmap_super_t *sb;
+        unsigned long flags;
+
+        if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
+                return 0;
+        spin_lock_irqsave(&bitmap->lock, flags);
+        if (!bitmap->sb_page) { /* no superblock */
+                spin_unlock_irqrestore(&bitmap->lock, flags);
+                return 0;
+        }
+        spin_unlock_irqrestore(&bitmap->lock, flags);
+        sb = (bitmap_super_t *)kmap(bitmap->sb_page);
+        sb->events = cpu_to_le64(bitmap->mddev->events);
+        if (!bitmap->mddev->degraded)
+                sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
+        kunmap(bitmap->sb_page);
+        return write_page(bitmap, bitmap->sb_page, 1);
+}
+
+/* print out the bitmap file superblock */
+void bitmap_print_sb(struct bitmap *bitmap)
+{
+        bitmap_super_t *sb;
+
+        if (!bitmap || !bitmap->sb_page)
+                return;
+        sb = (bitmap_super_t *)kmap(bitmap->sb_page);
+        printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
+        printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
+        printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
+        printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
+                                        *(__u32 *)(sb->uuid+0),
+                                        *(__u32 *)(sb->uuid+4),
+                                        *(__u32 *)(sb->uuid+8),
+                                        *(__u32 *)(sb->uuid+12));
+        printk(KERN_DEBUG "        events: %llu\n",
+                        (unsigned long long) le64_to_cpu(sb->events));
+        printk(KERN_DEBUG "events cleared: %llu\n",
+                        (unsigned long long) le64_to_cpu(sb->events_cleared));
+        printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
+        printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
+        printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
+        printk(KERN_DEBUG "     sync size: %llu KB\n",
+                        (unsigned long long)le64_to_cpu(sb->sync_size)/2);
+        kunmap(bitmap->sb_page);
+}
+
+/* read the superblock from the bitmap file and initialize some bitmap fields */
+static int bitmap_read_sb(struct bitmap *bitmap)
+{
+        char *reason = NULL;
+        bitmap_super_t *sb;
+        unsigned long chunksize, daemon_sleep;
+        unsigned long bytes_read;
+        unsigned long long events;
+        int err = -EINVAL;
+
+        /* page 0 is the superblock, read it... */
+        if (bitmap->file)
+                bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
+        else {
+                bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
+                bytes_read = PAGE_SIZE;
+        }
+        if (IS_ERR(bitmap->sb_page)) {
+                err = PTR_ERR(bitmap->sb_page);
+                bitmap->sb_page = NULL;
+                return err;
+        }
+
+        sb = (bitmap_super_t *)kmap(bitmap->sb_page);
+
+        if (bytes_read < sizeof(*sb)) { /* short read */
+                printk(KERN_INFO "%s: bitmap file superblock truncated\n",
+                        bmname(bitmap));
+                err = -ENOSPC;
+                goto out;
+        }
+
+        chunksize = le32_to_cpu(sb->chunksize);
+        daemon_sleep = le32_to_cpu(sb->daemon_sleep);
+
+        /* verify that the bitmap-specific fields are valid */
+        if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
+                reason = "bad magic";
+        else if (sb->version != cpu_to_le32(BITMAP_MAJOR))
+                reason = "unrecognized superblock version";
+        else if (chunksize < 512 || chunksize > (1024 * 1024 * 4))
+                reason = "bitmap chunksize out of range (512B - 4MB)";
+        else if ((1 << ffz(~chunksize)) != chunksize)
+                reason = "bitmap chunksize not a power of 2";
+        else if (daemon_sleep < 1 || daemon_sleep > 15)
+                reason = "daemon sleep period out of range";
+        if (reason) {
+                printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
+                        bmname(bitmap), reason);
+                goto out;
+        }
+
+        /* keep the array size field of the bitmap superblock up to date */
+        sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
+
+        if (!bitmap->mddev->persistent)
+                goto success;
+
+        /*
+         * if we have a persistent array superblock, compare the
+         * bitmap's UUID and event counter to the mddev's
+         */
+        if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
+                printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
+                        bmname(bitmap));
+                goto out;
+        }
+        events = le64_to_cpu(sb->events);
+        if (events < bitmap->mddev->events) {
+                printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
+                        "-- forcing full recovery\n", bmname(bitmap), events,
+                        (unsigned long long) bitmap->mddev->events);
+                sb->state |= BITMAP_STALE;
+        }
+success:
+        /* assign fields using values from superblock */
+        bitmap->chunksize = chunksize;
+        bitmap->daemon_sleep = daemon_sleep;
+        bitmap->flags |= sb->state;
+        bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
+        err = 0;
+out:
+        kunmap(bitmap->sb_page);
+        if (err)
+                bitmap_print_sb(bitmap);
+        return err;
+}
+
+enum bitmap_mask_op {
+        MASK_SET,
+        MASK_UNSET
+};
+
+/* record the state of the bitmap in the superblock */
+static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
+                                enum bitmap_mask_op op)
+{
+        bitmap_super_t *sb;
+        unsigned long flags;
+
+        spin_lock_irqsave(&bitmap->lock, flags);
+        if (!bitmap || !bitmap->sb_page) { /* can't set the state */
+                spin_unlock_irqrestore(&bitmap->lock, flags);
+                return;
+        }
+        page_cache_get(bitmap->sb_page);
+        spin_unlock_irqrestore(&bitmap->lock, flags);
+        sb = (bitmap_super_t *)kmap(bitmap->sb_page);
+        switch (op) {
+                case MASK_SET: sb->state |= bits;
+                                break;
+                case MASK_UNSET: sb->state &= ~bits;
+                                break;
+                default: BUG();
+        }
+        kunmap(bitmap->sb_page);
+        page_cache_release(bitmap->sb_page);
+}
+
+/*
+ * general bitmap file operations
+ */
+
+/* calculate the index of the page that contains this bit */
+static inline unsigned long file_page_index(unsigned long chunk)
+{
+        return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
+}
+
+/* calculate the (bit) offset of this bit within a page */
+static inline unsigned long file_page_offset(unsigned long chunk)
+{
+        return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
+}
+
+/*
+ * return a pointer to the page in the filemap that contains the given bit
+ *
+ * this lookup is complicated by the fact that the bitmap sb might be exactly
+ * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
+ * 0 or page 1
+ */
+static inline struct page *filemap_get_page(struct bitmap *bitmap,
+                                        unsigned long chunk)
+{
+        return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
+}
+
+
+static void bitmap_file_unmap(struct bitmap *bitmap)
+{
+        struct page **map, *sb_page;
+        unsigned long *attr;
+        int pages;
+        unsigned long flags;
+
+        spin_lock_irqsave(&bitmap->lock, flags);
+        map = bitmap->filemap;
+        bitmap->filemap = NULL;
+        attr = bitmap->filemap_attr;
+        bitmap->filemap_attr = NULL;
+        pages = bitmap->file_pages;
+        bitmap->file_pages = 0;
+        sb_page = bitmap->sb_page;
+        bitmap->sb_page = NULL;
+        spin_unlock_irqrestore(&bitmap->lock, flags);
+
+        while (pages--)
+                if (map[pages]->index != 0) /* 0 is sb_page, release it below */
+                        page_cache_release(map[pages]);
+        kfree(map);
+        kfree(attr);
+
+        if (sb_page)
+                page_cache_release(sb_page);
+}
+
+static void bitmap_stop_daemons(struct bitmap *bitmap);
+
+/* dequeue the next item in a page list -- don't call from irq context */
+static struct page_list *dequeue_page(struct bitmap *bitmap)
+{
+        struct page_list *item = NULL;
+        struct list_head *head = &bitmap->complete_pages;
+
+        spin_lock(&bitmap->write_lock);
+        if (list_empty(head))
+                goto out;
+        item = list_entry(head->prev, struct page_list, list);
+        list_del(head->prev);
+out:
+        spin_unlock(&bitmap->write_lock);
+        return item;
+}
+
+static void drain_write_queues(struct bitmap *bitmap)
+{
+        struct page_list *item;
+
+        while ((item = dequeue_page(bitmap))) {
+                /* don't bother to wait */
+                page_cache_release(item->page);
+                mempool_free(item, bitmap->write_pool);
+        }
+
+        wake_up(&bitmap->write_wait);
+}
+
+static void bitmap_file_put(struct bitmap *bitmap)
+{
+        struct file *file;
+        struct inode *inode;
+        unsigned long flags;
+
+        spin_lock_irqsave(&bitmap->lock, flags);
+        file = bitmap->file;
+        bitmap->file = NULL;
+        spin_unlock_irqrestore(&bitmap->lock, flags);
+
+        bitmap_stop_daemons(bitmap);
+
+        drain_write_queues(bitmap);
+
+        bitmap_file_unmap(bitmap);
+
+        if (file) {
+                inode = file->f_mapping->host;
+                spin_lock(&inode->i_lock);
+                atomic_set(&inode->i_writecount, 1); /* allow writes again */
+                spin_unlock(&inode->i_lock);
+                fput(file);
+        }
+}
+
+
+/*
+ * bitmap_file_kick - if an error occurs while manipulating the bitmap file
+ * then it is no longer reliable, so we stop using it and we mark the file
+ * as failed in the superblock
+ */
+static void bitmap_file_kick(struct bitmap *bitmap)
+{
+        char *path, *ptr = NULL;
+
+        bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
+        bitmap_update_sb(bitmap);
+
+        if (bitmap->file) {
+                path = kmalloc(PAGE_SIZE, GFP_KERNEL);
+                if (path)
+                        ptr = file_path(bitmap->file, path, PAGE_SIZE);
+
+                printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
+                       bmname(bitmap), ptr ? ptr : "");
+
+                kfree(path);
+        }
+
+        bitmap_file_put(bitmap);
+
+        return;
+}
+
+enum bitmap_page_attr {
+        BITMAP_PAGE_DIRTY = 1, // there are set bits that need to be synced
+        BITMAP_PAGE_CLEAN = 2, // there are bits that might need to be cleared
+        BITMAP_PAGE_NEEDWRITE=4, // there are cleared bits that need to be synced
+};
+
+static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
+                                enum bitmap_page_attr attr)
+{
+        bitmap->filemap_attr[page->index] |= attr;
+}
+
+static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
+                                enum bitmap_page_attr attr)
+{
+        bitmap->filemap_attr[page->index] &= ~attr;
+}
+
+static inline unsigned long get_page_attr(struct bitmap *bitmap, struct page *page)
+{
+        return bitmap->filemap_attr[page->index];
+}
+
+/*
+ * bitmap_file_set_bit -- called before performing a write to the md device
+ * to set (and eventually sync) a particular bit in the bitmap file
+ *
+ * we set the bit immediately, then we record the page number so that
+ * when an unplug occurs, we can flush the dirty pages out to disk
+ */
+static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
+{
+        unsigned long bit;
+        struct page *page;
+        void *kaddr;
+        unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
+
+        if (!bitmap->filemap) {
+                return;
+        }
+
+        page = filemap_get_page(bitmap, chunk);
+        bit = file_page_offset(chunk);
+
+
+        /* make sure the page stays cached until it gets written out */
+        if (! (get_page_attr(bitmap, page) & BITMAP_PAGE_DIRTY))
+                page_cache_get(page);
+
+        /* set the bit */
+        kaddr = kmap_atomic(page, KM_USER0);
+        set_bit(bit, kaddr);
+        kunmap_atomic(kaddr, KM_USER0);
+        PRINTK("set file bit %lu page %lu\n", bit, page->index);
+
+        /* record page number so it gets flushed to disk when unplug occurs */
+        set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
+
+}
+
+/* this gets called when the md device is ready to unplug its underlying
+ * (slave) device queues -- before we let any writes go down, we need to
+ * sync the dirty pages of the bitmap file to disk */
+int bitmap_unplug(struct bitmap *bitmap)
+{
+        unsigned long i, attr, flags;
+        struct page *page;
+        int wait = 0;
+        int err;
+
+        if (!bitmap)
+                return 0;
+
+        /* look at each page to see if there are any set bits that need to be
+         * flushed out to disk */
+        for (i = 0; i < bitmap->file_pages; i++) {
+                spin_lock_irqsave(&bitmap->lock, flags);
+                if (!bitmap->filemap) {
+                        spin_unlock_irqrestore(&bitmap->lock, flags);
+                        return 0;
+                }
+                page = bitmap->filemap[i];
+                attr = get_page_attr(bitmap, page);
+                clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
+                clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
+                if ((attr & BITMAP_PAGE_DIRTY))
+                        wait = 1;
+                spin_unlock_irqrestore(&bitmap->lock, flags);
+
+                if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE)) {
+                        err = write_page(bitmap, page, 0);
+                        if (err == -EAGAIN) {
+                                if (attr & BITMAP_PAGE_DIRTY)
+                                        err = write_page(bitmap, page, 1);
+                                else
+                                        err = 0;
+                        }
+                        if (err)
+                                return 1;
+                }
+        }
+        if (wait) { /* if any writes were performed, we need to wait on them */
+                if (bitmap->file) {
+                        spin_lock_irq(&bitmap->write_lock);
+                        wait_event_lock_irq(bitmap->write_wait,
+                                            list_empty(&bitmap->complete_pages), bitmap->write_lock,
+                                            wake_up_process(bitmap->writeback_daemon->tsk));
+                        spin_unlock_irq(&bitmap->write_lock);
+                } else
+                        wait_event(bitmap->mddev->sb_wait,
+                                   atomic_read(&bitmap->mddev->pending_writes)==0);
+        }
+        return 0;
+}
+
+static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
+        unsigned long sectors, int in_sync);
+/* * bitmap_init_from_disk -- called at bitmap_create time to initialize
+ * the in-memory bitmap from the on-disk bitmap -- also, sets up the
+ * memory mapping of the bitmap file
+ * Special cases:
+ *   if there's no bitmap file, or if the bitmap file had been
+ *   previously kicked from the array, we mark all the bits as
+ *   1's in order to cause a full resync.
+ */
+static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
+{
+        unsigned long i, chunks, index, oldindex, bit;
+        struct page *page = NULL, *oldpage = NULL;
+        unsigned long num_pages, bit_cnt = 0;
+        struct file *file;
+        unsigned long bytes, offset, dummy;
+        int outofdate;
+        int ret = -ENOSPC;
+
+        chunks = bitmap->chunks;
+        file = bitmap->file;
+
+        BUG_ON(!file && !bitmap->offset);
+
+#if INJECT_FAULTS_3
+        outofdate = 1;
+#else
+        outofdate = bitmap->flags & BITMAP_STALE;
+#endif
+        if (outofdate)
+                printk(KERN_INFO "%s: bitmap file is out of date, doing full "
+                        "recovery\n", bmname(bitmap));
+
+        bytes = (chunks + 7) / 8;
+
+        num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
+
+        if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
+                printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
+                        bmname(bitmap),
+                        (unsigned long) i_size_read(file->f_mapping->host),
+                        bytes + sizeof(bitmap_super_t));
+                goto out;
+        }
+
+        ret = -ENOMEM;
+
+        bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
+        if (!bitmap->filemap)
+                goto out;
+
+        bitmap->filemap_attr = kmalloc(sizeof(long) * num_pages, GFP_KERNEL);
+        if (!bitmap->filemap_attr)
+                goto out;
+
+        memset(bitmap->filemap_attr, 0, sizeof(long) * num_pages);
+
+        oldindex = ~0L;
+
+        for (i = 0; i < chunks; i++) {
+                index = file_page_index(i);
+                bit = file_page_offset(i);
+                if (index != oldindex) { /* this is a new page, read it in */
+                        /* unmap the old page, we're done with it */
+                        if (oldpage != NULL)
+                                kunmap(oldpage);
+                        if (index == 0) {
+                                /*
+                                 * if we're here then the superblock page
+                                 * contains some bits (PAGE_SIZE != sizeof sb)
+                                 * we've already read it in, so just use it
+                                 */
+                                page = bitmap->sb_page;
+                                offset = sizeof(bitmap_super_t);
+                        } else if (file) {
+                                page = read_page(file, index, &dummy);
+                                offset = 0;
+                        } else {
+                                page = read_sb_page(bitmap->mddev, bitmap->offset, index);
+                                offset = 0;
+                        }
+                        if (IS_ERR(page)) { /* read error */
+                                ret = PTR_ERR(page);
+                                goto out;
+                        }
+
+                        oldindex = index;
+                        oldpage = page;
+                        kmap(page);
+
+                        if (outofdate) {
+                                /*
+                                 * if bitmap is out of date, dirty the
+                                 * whole page and write it out
+                                 */
+                                memset(page_address(page) + offset, 0xff,
+                                        PAGE_SIZE - offset);
+                                ret = write_page(bitmap, page, 1);
+                                if (ret) {
+                                        kunmap(page);
+                                        /* release, page not in filemap yet */
+                                        page_cache_release(page);
+                                        goto out;
+                                }
+                        }
+
+                        bitmap->filemap[bitmap->file_pages++] = page;
+                }
+                if (test_bit(bit, page_address(page))) {
+                        /* if the disk bit is set, set the memory bit */
+                        bitmap_set_memory_bits(bitmap,
+                                        i << CHUNK_BLOCK_SHIFT(bitmap), 1, in_sync);
+                        bit_cnt++;
+                }
+        }
+
+        /* everything went OK */
+        ret = 0;
+        bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
+
+        if (page) /* unmap the last page */
+                kunmap(page);
+
+        if (bit_cnt) { /* Kick recovery if any bits were set */
+                set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
+                md_wakeup_thread(bitmap->mddev->thread);
+        }
+
+out:
+        printk(KERN_INFO "%s: bitmap initialized from disk: "
+                "read %lu/%lu pages, set %lu bits, status: %d\n",
+                bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
+
+        return ret;
+}
+
+void bitmap_write_all(struct bitmap *bitmap)
+{
+        /* We don't actually write all bitmap blocks here,
+         * just flag them as needing to be written
+         */
+
+        unsigned long chunks = bitmap->chunks;
+        unsigned long bytes = (chunks+7)/8 + sizeof(bitmap_super_t);
+        unsigned long num_pages = (bytes + PAGE_SIZE-1) / PAGE_SIZE;
+        while (num_pages--)
+                bitmap->filemap_attr[num_pages] |= BITMAP_PAGE_NEEDWRITE;
+}
+
+
+static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
+{
+        sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
+        unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
+        bitmap->bp[page].count += inc;
+/*
+        if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
+                              (unsigned long long)offset, inc, bitmap->bp[page].count);
+*/
+        bitmap_checkfree(bitmap, page);
+}
+static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
+                                            sector_t offset, int *blocks,
+                                            int create);
+
+/*
+ * bitmap daemon -- periodically wakes up to clean bits and flush pages
+ *                      out to disk
+ */
+
+int bitmap_daemon_work(struct bitmap *bitmap)
+{
+        unsigned long j;
+        unsigned long flags;
+        struct page *page = NULL, *lastpage = NULL;
+        int err = 0;
+        int blocks;
+        int attr;
+
+        if (bitmap == NULL)
+                return 0;
+        if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
+                return 0;
+        bitmap->daemon_lastrun = jiffies;
+
+        for (j = 0; j < bitmap->chunks; j++) {
+                bitmap_counter_t *bmc;
+                spin_lock_irqsave(&bitmap->lock, flags);
+                if (!bitmap->filemap) {
+                        /* error or shutdown */
+                        spin_unlock_irqrestore(&bitmap->lock, flags);
+                        break;
+                }
+
+                page = filemap_get_page(bitmap, j);
+
+                if (page != lastpage) {
+                        /* skip this page unless it's marked as needing cleaning */
+                        if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
+                                if (attr & BITMAP_PAGE_NEEDWRITE) {
+                                        page_cache_get(page);
+                                        clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
+                                }
+                                spin_unlock_irqrestore(&bitmap->lock, flags);
+                                if (attr & BITMAP_PAGE_NEEDWRITE) {
+                                        switch (write_page(bitmap, page, 0)) {
+                                        case -EAGAIN:
+                                                set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
+                                                break;
+                                        case 0:
+                                                break;
+                                        default:
+                                                bitmap_file_kick(bitmap);
+                                        }
+                                        page_cache_release(page);
+                                }
+                                continue;
+                        }
+
+                        /* grab the new page, sync and release the old */
+                        page_cache_get(page);
+                        if (lastpage != NULL) {
+                                if (get_page_attr(bitmap, lastpage) & BITMAP_PAGE_NEEDWRITE) {
+                                        clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+                                        spin_unlock_irqrestore(&bitmap->lock, flags);
+                                        err = write_page(bitmap, lastpage, 0);
+                                        if (err == -EAGAIN) {
+                                                err = 0;
+                                                set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+                                        }
+                                } else {
+                                        set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+                                        spin_unlock_irqrestore(&bitmap->lock, flags);
+                                }
+                                kunmap(lastpage);
+                                page_cache_release(lastpage);
+                                if (err)
+                                        bitmap_file_kick(bitmap);
+                        } else
+                                spin_unlock_irqrestore(&bitmap->lock, flags);
+                        lastpage = page;
+                        kmap(page);
+/*
+                        printk("bitmap clean at page %lu\n", j);
+*/
+                        spin_lock_irqsave(&bitmap->lock, flags);
+                        clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
+                }
+                bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
+                                        &blocks, 0);
+                if (bmc) {
+/*
+  if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
+*/
+                        if (*bmc == 2) {
+                                *bmc=1; /* maybe clear the bit next time */
+                                set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
+                        } else if (*bmc == 1) {
+                                /* we can clear the bit */
+                                *bmc = 0;
+                                bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
+                                                  -1);
+
+                                /* clear the bit */
+                                clear_bit(file_page_offset(j), page_address(page));
+                        }
+                }
+                spin_unlock_irqrestore(&bitmap->lock, flags);
+        }
+
+        /* now sync the final page */
+        if (lastpage != NULL) {
+                kunmap(lastpage);
+                spin_lock_irqsave(&bitmap->lock, flags);
+                if (get_page_attr(bitmap, lastpage) &BITMAP_PAGE_NEEDWRITE) {
+                        clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+                        spin_unlock_irqrestore(&bitmap->lock, flags);
+                        err = write_page(bitmap, lastpage, 0);
+                        if (err == -EAGAIN) {
+                                set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+                                err = 0;
+                        }
+                } else {
+                        set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
+                        spin_unlock_irqrestore(&bitmap->lock, flags);
+                }
+
+                page_cache_release(lastpage);
+        }
+
+        return err;
+}
+
+static void daemon_exit(struct bitmap *bitmap, mdk_thread_t **daemon)
+{
+        mdk_thread_t *dmn;
+        unsigned long flags;
+
+        /* if no one is waiting on us, we'll free the md thread struct
+         * and exit, otherwise we let the waiter clean things up */
+        spin_lock_irqsave(&bitmap->lock, flags);
+        if ((dmn = *daemon)) { /* no one is waiting, cleanup and exit */
+                *daemon = NULL;
+                spin_unlock_irqrestore(&bitmap->lock, flags);
+                kfree(dmn);
+                complete_and_exit(NULL, 0); /* do_exit not exported */
+        }
+        spin_unlock_irqrestore(&bitmap->lock, flags);
+}
+
+static void bitmap_writeback_daemon(mddev_t *mddev)
+{
+        struct bitmap *bitmap = mddev->bitmap;
+        struct page *page;
+        struct page_list *item;
+        int err = 0;
+
+        if (signal_pending(current)) {
+                printk(KERN_INFO
+                       "%s: bitmap writeback daemon got signal, exiting...\n",
+                       bmname(bitmap));
+                err = -EINTR;
+                goto out;
+        }
+
+        PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
+        /* wait on bitmap page writebacks */
+        while ((item = dequeue_page(bitmap))) {
+                page = item->page;
+                mempool_free(item, bitmap->write_pool);
+                PRINTK("wait on page writeback: %p\n", page);
+                wait_on_page_writeback(page);
+                PRINTK("finished page writeback: %p\n", page);
+
+                err = PageError(page);
+                page_cache_release(page);
+                if (err) {
+                        printk(KERN_WARNING "%s: bitmap file writeback "
+                               "failed (page %lu): %d\n",
+                               bmname(bitmap), page->index, err);
+                        bitmap_file_kick(bitmap);
+                        goto out;
+                }
+        }
+ out:
+        wake_up(&bitmap->write_wait);
+        if (err) {
+                printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
+                       bmname(bitmap), err);
+                daemon_exit(bitmap, &bitmap->writeback_daemon);
+        }
+}
+
+static int bitmap_start_daemon(struct bitmap *bitmap, mdk_thread_t **ptr,
+                                void (*func)(mddev_t *), char *name)
+{
+        mdk_thread_t *daemon;
+        unsigned long flags;
+        char namebuf[32];
+
+        spin_lock_irqsave(&bitmap->lock, flags);
+        *ptr = NULL;
+
+        if (!bitmap->file) /* no need for daemon if there's no backing file */
+                goto out_unlock;
+
+        spin_unlock_irqrestore(&bitmap->lock, flags);
+
+#if INJECT_FATAL_FAULT_2
+        daemon = NULL;
+#else
+        sprintf(namebuf, "%%s_%s", name);
+        daemon = md_register_thread(func, bitmap->mddev, namebuf);
+#endif
+        if (!daemon) {
+                printk(KERN_ERR "%s: failed to start bitmap daemon\n",
+                        bmname(bitmap));
+                return -ECHILD;
+        }
+
+        spin_lock_irqsave(&bitmap->lock, flags);
+        *ptr = daemon;
+
+        md_wakeup_thread(daemon); /* start it running */
+
+        PRINTK("%s: %s daemon (pid %d) started...\n",
+                bmname(bitmap), name, daemon->tsk->pid);
+out_unlock:
+        spin_unlock_irqrestore(&bitmap->lock, flags);
+        return 0;
+}
+
+static int bitmap_start_daemons(struct bitmap *bitmap)
+{
+        int err = bitmap_start_daemon(bitmap, &bitmap->writeback_daemon,
+                                        bitmap_writeback_daemon, "bitmap_wb");
+        return err;
+}
+
+static void bitmap_stop_daemon(struct bitmap *bitmap, mdk_thread_t **ptr)
+{
+        mdk_thread_t *daemon;
+        unsigned long flags;
+
+        spin_lock_irqsave(&bitmap->lock, flags);
+        daemon = *ptr;
+        *ptr = NULL;
+        spin_unlock_irqrestore(&bitmap->lock, flags);
+        if (daemon)
+                md_unregister_thread(daemon); /* destroy the thread */
+}
+
+static void bitmap_stop_daemons(struct bitmap *bitmap)
+{
+        /* the daemons can't stop themselves... they'll just exit instead... */
+        if (bitmap->writeback_daemon &&
+            current->pid != bitmap->writeback_daemon->tsk->pid)
+                bitmap_stop_daemon(bitmap, &bitmap->writeback_daemon);
+}
+
+static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
+                                            sector_t offset, int *blocks,
+                                            int create)
+{
+        /* If 'create', we might release the lock and reclaim it.
+         * The lock must have been taken with interrupts enabled.
+         * If !create, we don't release the lock.
+         */
+        sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
+        unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
+        unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
+        sector_t csize;
+
+        if (bitmap_checkpage(bitmap, page, create) < 0) {
+                csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
+                *blocks = csize - (offset & (csize- 1));
+                return NULL;
+        }
+        /* now locked ... */
+
+        if (bitmap->bp[page].hijacked) { /* hijacked pointer */
+                /* should we use the first or second counter field
+                 * of the hijacked pointer? */
+                int hi = (pageoff > PAGE_COUNTER_MASK);
+                csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
+                                          PAGE_COUNTER_SHIFT - 1);
+                *blocks = csize - (offset & (csize- 1));
+                return  &((bitmap_counter_t *)
+                          &bitmap->bp[page].map)[hi];
+        } else { /* page is allocated */
+                csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
+                *blocks = csize - (offset & (csize- 1));
+                return (bitmap_counter_t *)
+                        &(bitmap->bp[page].map[pageoff]);
+        }
+}
+
+int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors)
+{
+        if (!bitmap) return 0;
+        while (sectors) {
+                int blocks;
+                bitmap_counter_t *bmc;
+
+                spin_lock_irq(&bitmap->lock);
+                bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
+                if (!bmc) {
+                        spin_unlock_irq(&bitmap->lock);
+                        return 0;
+                }
+
+                switch(*bmc) {
+                case 0:
+                        bitmap_file_set_bit(bitmap, offset);
+                        bitmap_count_page(bitmap,offset, 1);
+                        blk_plug_device(bitmap->mddev->queue);
+                        /* fall through */
+                case 1:
+                        *bmc = 2;
+                }
+                if ((*bmc & COUNTER_MAX) == COUNTER_MAX) BUG();
+                (*bmc)++;
+
+                spin_unlock_irq(&bitmap->lock);
+
+                offset += blocks;
+                if (sectors > blocks)
+                        sectors -= blocks;
+                else sectors = 0;
+        }
+        return 0;
+}
+
+void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
+                     int success)
+{
+        if (!bitmap) return;
+        while (sectors) {
+                int blocks;
+                unsigned long flags;
+                bitmap_counter_t *bmc;
+
+                spin_lock_irqsave(&bitmap->lock, flags);
+                bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
+                if (!bmc) {
+                        spin_unlock_irqrestore(&bitmap->lock, flags);
+                        return;
+                }
+
+                if (!success && ! (*bmc & NEEDED_MASK))
+                        *bmc |= NEEDED_MASK;
+
+                (*bmc)--;
+                if (*bmc <= 2) {
+                        set_page_attr(bitmap,
+                                      filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
+                                      BITMAP_PAGE_CLEAN);
+                }
+                spin_unlock_irqrestore(&bitmap->lock, flags);
+                offset += blocks;
+                if (sectors > blocks)
+                        sectors -= blocks;
+                else sectors = 0;
+        }
+}
+
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks)
+{
+        bitmap_counter_t *bmc;
+        int rv;
+        if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
+                *blocks = 1024;
+                return 1; /* always resync if no bitmap */
+        }
+        spin_lock_irq(&bitmap->lock);
+        bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
+        rv = 0;
+        if (bmc) {
+                /* locked */
+                if (RESYNC(*bmc))
+                        rv = 1;
+                else if (NEEDED(*bmc)) {
+                        rv = 1;
+                        *bmc |= RESYNC_MASK;
+                        *bmc &= ~NEEDED_MASK;
+                }
+        }
+        spin_unlock_irq(&bitmap->lock);
+        return rv;
+}
+
+void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
+{
+        bitmap_counter_t *bmc;
+        unsigned long flags;
+/*
+        if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
+*/      if (bitmap == NULL) {
+                *blocks = 1024;
+                return;
+        }
+        spin_lock_irqsave(&bitmap->lock, flags);
+        bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
+        if (bmc == NULL)
+                goto unlock;
+        /* locked */
+/*
+        if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
+*/
+        if (RESYNC(*bmc)) {
+                *bmc &= ~RESYNC_MASK;
+
+                if (!NEEDED(*bmc) && aborted)
+                        *bmc |= NEEDED_MASK;
+                else {
+                        if (*bmc <= 2) {
+                                set_page_attr(bitmap,
+                                              filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
+                                              BITMAP_PAGE_CLEAN);
+                        }
+                }
+        }
+ unlock:
+        spin_unlock_irqrestore(&bitmap->lock, flags);
+}
+
+void bitmap_close_sync(struct bitmap *bitmap)
+{
+        /* Sync has finished, and any bitmap chunks that weren't synced
+         * properly have been aborted.  It remains to us to clear the
+         * RESYNC bit wherever it is still on
+         */
+        sector_t sector = 0;
+        int blocks;
+        if (!bitmap) return;
+        while (sector < bitmap->mddev->resync_max_sectors) {
+                bitmap_end_sync(bitmap, sector, &blocks, 0);
+/*
+                if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
+                                         (unsigned long long)sector, blocks);
+*/              sector += blocks;
+        }
+}
+
+static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,
+                                   unsigned long sectors, int in_sync)
+{
+        /* For each chunk covered by any of these sectors, set the
+         * counter to 1 and set resync_needed unless in_sync.  They should all
+         * be 0 at this point
+         */
+        while (sectors) {
+                int secs;
+                bitmap_counter_t *bmc;
+                spin_lock_irq(&bitmap->lock);
+                bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
+                if (!bmc) {
+                        spin_unlock_irq(&bitmap->lock);
+                        return;
+                }
+                if (! *bmc) {
+                        struct page *page;
+                        *bmc = 1 | (in_sync? 0 : NEEDED_MASK);
+                        bitmap_count_page(bitmap, offset, 1);
+                        page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
+                        set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
+                }
+                spin_unlock_irq(&bitmap->lock);
+                if (sectors > secs)
+                        sectors -= secs;
+                else
+                        sectors = 0;
+        }
+}
+
+/*
+ * free memory that was allocated
+ */
+void bitmap_destroy(mddev_t *mddev)
+{
+        unsigned long k, pages;
+        struct bitmap_page *bp;
+        struct bitmap *bitmap = mddev->bitmap;
+
+        if (!bitmap) /* there was no bitmap */
+                return;
+
+        mddev->bitmap = NULL; /* disconnect from the md device */
+
+        /* release the bitmap file and kill the daemon */
+        bitmap_file_put(bitmap);
+
+        bp = bitmap->bp;
+        pages = bitmap->pages;
+
+        /* free all allocated memory */
+
+        mempool_destroy(bitmap->write_pool);
+
+        if (bp) /* deallocate the page memory */
+                for (k = 0; k < pages; k++)
+                        if (bp[k].map && !bp[k].hijacked)
+                                kfree(bp[k].map);
+        kfree(bp);
+        kfree(bitmap);
+}
+
+/*
+ * initialize the bitmap structure
+ * if this returns an error, bitmap_destroy must be called to do clean up
+ */
+int bitmap_create(mddev_t *mddev)
+{
+        struct bitmap *bitmap;
+        unsigned long blocks = mddev->resync_max_sectors;
+        unsigned long chunks;
+        unsigned long pages;
+        struct file *file = mddev->bitmap_file;
+        int err;
+
+        BUG_ON(sizeof(bitmap_super_t) != 256);
+
+        if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
+                return 0;
+
+        BUG_ON(file && mddev->bitmap_offset);
+
+        bitmap = kmalloc(sizeof(*bitmap), GFP_KERNEL);
+        if (!bitmap)
+                return -ENOMEM;
+
+        memset(bitmap, 0, sizeof(*bitmap));
+
+        spin_lock_init(&bitmap->lock);
+        bitmap->mddev = mddev;
+        mddev->bitmap = bitmap;
+
+        spin_lock_init(&bitmap->write_lock);
+        INIT_LIST_HEAD(&bitmap->complete_pages);
+        init_waitqueue_head(&bitmap->write_wait);
+        bitmap->write_pool = mempool_create(WRITE_POOL_SIZE, write_pool_alloc,
+                                write_pool_free, NULL);
+        if (!bitmap->write_pool)
+                return -ENOMEM;
+
+        bitmap->file = file;
+        bitmap->offset = mddev->bitmap_offset;
+        if (file) get_file(file);
+        /* read superblock from bitmap file (this sets bitmap->chunksize) */
+        err = bitmap_read_sb(bitmap);
+        if (err)
+                return err;
+
+        bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
+                                        sizeof(bitmap->chunksize));
+
+        /* now that chunksize and chunkshift are set, we can use these macros */
+        chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
+                        CHUNK_BLOCK_RATIO(bitmap);
+        pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
+
+        BUG_ON(!pages);
+
+        bitmap->chunks = chunks;
+        bitmap->pages = pages;
+        bitmap->missing_pages = pages;
+        bitmap->counter_bits = COUNTER_BITS;
+
+        bitmap->syncchunk = ~0UL;
+
+#if INJECT_FATAL_FAULT_1
+        bitmap->bp = NULL;
+#else
+        bitmap->bp = kmalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
+#endif
+        if (!bitmap->bp)
+                return -ENOMEM;
+        memset(bitmap->bp, 0, pages * sizeof(*bitmap->bp));
+
+        bitmap->flags |= BITMAP_ACTIVE;
+
+        /* now that we have some pages available, initialize the in-memory
+         * bitmap from the on-disk bitmap */
+        err = bitmap_init_from_disk(bitmap, mddev->recovery_cp == MaxSector);
+        if (err)
+                return err;
+
+        printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
+                pages, bmname(bitmap));
+
+        /* kick off the bitmap daemons */
+        err = bitmap_start_daemons(bitmap);
+        if (err)
+                return err;
+        return bitmap_update_sb(bitmap);
+}
+
+/* the bitmap API -- for raid personalities */
+EXPORT_SYMBOL(bitmap_startwrite);
+EXPORT_SYMBOL(bitmap_endwrite);
+EXPORT_SYMBOL(bitmap_start_sync);
+EXPORT_SYMBOL(bitmap_end_sync);
+EXPORT_SYMBOL(bitmap_unplug);
+EXPORT_SYMBOL(bitmap_close_sync);
+EXPORT_SYMBOL(bitmap_daemon_work);
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 0dd6c2b5391b..d0a4bab220e5 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -704,8 +704,7 @@ static void crypt_dtr(struct dm_target *ti)
         mempool_destroy(cc->page_pool);
         mempool_destroy(cc->io_pool);
 
-        if (cc->iv_mode)
-                kfree(cc->iv_mode);
+        kfree(cc->iv_mode);
         if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
                 cc->iv_gen_ops->dtr(cc);
         crypto_free_tfm(cc->tfm);
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 1e97b3c12bd5..0c1b8520ef86 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -985,6 +985,9 @@ static int do_end_io(struct multipath *m, struct bio *bio,
         if (!error)
                 return 0;       /* I/O complete */
 
+        if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
+                return error;
+
         spin_lock(&m->lock);
         if (!m->nr_valid_paths) {
                 if (!m->queue_if_no_path || m->suspended) {
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 161e9aa87291..8d740013d74d 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -217,8 +217,7 @@ static int linear_run (mddev_t *mddev)
         return 0;
 
 out:
-        if (conf)
-                kfree(conf);
+        kfree(conf);
         return 1;
 }
 
@@ -269,9 +268,8 @@ static int linear_make_request (request_queue_t *q, struct bio *bio)
                  * split it.
                  */
                 struct bio_pair *bp;
-                bp = bio_split(bio, bio_split_pool, 
-                               (bio->bi_sector + (bio->bi_size >> 9) -
-                                (tmp_dev->offset + tmp_dev->size))<<1);
+                bp = bio_split(bio, bio_split_pool,
+                               ((tmp_dev->offset + tmp_dev->size)<<1) - bio->bi_sector);
                 if (linear_make_request(q, &bp->bio1))
                         generic_make_request(&bp->bio1);
                 if (linear_make_request(q, &bp->bio2))
diff --git a/drivers/md/md.c b/drivers/md/md.c
index d899204d3743..0c6b5b6baff6 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -19,6 +19,9 @@
 
      Neil Brown <neilb@cse.unsw.edu.au>.
 
+   - persistent bitmap code
+     Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.
+
    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)
@@ -33,6 +36,7 @@
 #include <linux/config.h>
 #include <linux/linkage.h>
 #include <linux/raid/md.h>
+#include <linux/raid/bitmap.h>
 #include <linux/sysctl.h>
 #include <linux/devfs_fs_kernel.h>
 #include <linux/buffer_head.h> /* for invalidate_bdev */
@@ -40,6 +44,8 @@
 
 #include <linux/init.h>
 
+#include <linux/file.h>
+
 #ifdef CONFIG_KMOD
 #include <linux/kmod.h>
 #endif
@@ -189,8 +195,7 @@ static mddev_t * mddev_find(dev_t unit)
                 if (mddev->unit == unit) {
                         mddev_get(mddev);
                         spin_unlock(&all_mddevs_lock);
-                        if (new)
-                                kfree(new);
+                        kfree(new);
                         return mddev;
                 }
 
@@ -218,6 +223,8 @@ static mddev_t * mddev_find(dev_t unit)
         INIT_LIST_HEAD(&new->all_mddevs);
         init_timer(&new->safemode_timer);
         atomic_set(&new->active, 1);
+        spin_lock_init(&new->write_lock);
+        init_waitqueue_head(&new->sb_wait);
 
         new->queue = blk_alloc_queue(GFP_KERNEL);
         if (!new->queue) {
@@ -320,6 +327,40 @@ static void free_disk_sb(mdk_rdev_t * rdev)
 }
 
 
+static int super_written(struct bio *bio, unsigned int bytes_done, int error)
+{
+        mdk_rdev_t *rdev = bio->bi_private;
+        if (bio->bi_size)
+                return 1;
+
+        if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags))
+                md_error(rdev->mddev, rdev);
+
+        if (atomic_dec_and_test(&rdev->mddev->pending_writes))
+                wake_up(&rdev->mddev->sb_wait);
+        return 0;
+}
+
+void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
+                   sector_t sector, int size, struct page *page)
+{
+        /* write first size bytes of page to sector of rdev
+         * Increment mddev->pending_writes before returning
+         * and decrement it on completion, waking up sb_wait
+         * if zero is reached.
+         * If an error occurred, call md_error
+         */
+        struct bio *bio = bio_alloc(GFP_NOIO, 1);
+
+        bio->bi_bdev = rdev->bdev;
+        bio->bi_sector = sector;
+        bio_add_page(bio, page, size, 0);
+        bio->bi_private = rdev;
+        bio->bi_end_io = super_written;
+        atomic_inc(&mddev->pending_writes);
+        submit_bio((1<<BIO_RW)|(1<<BIO_RW_SYNC), bio);
+}
+
 static int bi_complete(struct bio *bio, unsigned int bytes_done, int error)
 {
         if (bio->bi_size)
@@ -329,7 +370,7 @@ static int bi_complete(struct bio *bio, unsigned int bytes_done, int error)
         return 0;
 }
 
-static int sync_page_io(struct block_device *bdev, sector_t sector, int size,
+int sync_page_io(struct block_device *bdev, sector_t sector, int size,
                    struct page *page, int rw)
 {
         struct bio *bio = bio_alloc(GFP_NOIO, 1);
@@ -416,11 +457,8 @@ static int sb_equal(mdp_super_t *sb1, mdp_super_t *sb2)
                 ret = 1;
 
 abort:
-        if (tmp1)
-                kfree(tmp1);
-        if (tmp2)
-                kfree(tmp2);
-
+        kfree(tmp1);
+        kfree(tmp2);
         return ret;
 }
 
@@ -569,6 +607,8 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
         mdp_disk_t *desc;
         mdp_super_t *sb = (mdp_super_t *)page_address(rdev->sb_page);
 
+        rdev->raid_disk = -1;
+        rdev->in_sync = 0;
         if (mddev->raid_disks == 0) {
                 mddev->major_version = 0;
                 mddev->minor_version = sb->minor_version;
@@ -599,16 +639,35 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                 memcpy(mddev->uuid+12,&sb->set_uuid3, 4);
 
                 mddev->max_disks = MD_SB_DISKS;
-        } else {
-                __u64 ev1;
-                ev1 = md_event(sb);
+
+                if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
+                    mddev->bitmap_file == NULL) {
+                        if (mddev->level != 1) {
+                                /* FIXME use a better test */
+                                printk(KERN_WARNING "md: bitmaps only support for raid1\n");
+                                return -EINVAL;
+                        }
+                        mddev->bitmap_offset = (MD_SB_BYTES >> 9);
+                }
+
+        } else if (mddev->pers == NULL) {
+                /* Insist on good event counter while assembling */
+                __u64 ev1 = md_event(sb);
                 ++ev1;
                 if (ev1 < mddev->events) 
                         return -EINVAL;
-        }
+        } else if (mddev->bitmap) {
+                /* if adding to array with a bitmap, then we can accept an
+                 * older device ... but not too old.
+                 */
+                __u64 ev1 = md_event(sb);
+                if (ev1 < mddev->bitmap->events_cleared)
+                        return 0;
+        } else /* just a hot-add of a new device, leave raid_disk at -1 */
+                return 0;
+
         if (mddev->level != LEVEL_MULTIPATH) {
-                rdev->raid_disk = -1;
-                rdev->in_sync = rdev->faulty = 0;
+                rdev->faulty = 0;
                 desc = sb->disks + rdev->desc_nr;
 
                 if (desc->state & (1<<MD_DISK_FAULTY))
@@ -618,7 +677,8 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                         rdev->in_sync = 1;
                         rdev->raid_disk = desc->raid_disk;
                 }
-        }
+        } else /* MULTIPATH are always insync */
+                rdev->in_sync = 1;
         return 0;
 }
 
@@ -683,6 +743,9 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
         sb->layout = mddev->layout;
         sb->chunk_size = mddev->chunk_size;
 
+        if (mddev->bitmap && mddev->bitmap_file == NULL)
+                sb->state |= (1<<MD_SB_BITMAP_PRESENT);
+
         sb->disks[0].state = (1<<MD_DISK_REMOVED);
         ITERATE_RDEV(mddev,rdev2,tmp) {
                 mdp_disk_t *d;
@@ -780,7 +843,7 @@ static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
         case 0:
                 sb_offset = rdev->bdev->bd_inode->i_size >> 9;
                 sb_offset -= 8*2;
-                sb_offset &= ~(4*2-1);
+                sb_offset &= ~(sector_t)(4*2-1);
                 /* convert from sectors to K */
                 sb_offset /= 2;
                 break;
@@ -860,6 +923,8 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
 {
         struct mdp_superblock_1 *sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
 
+        rdev->raid_disk = -1;
+        rdev->in_sync = 0;
         if (mddev->raid_disks == 0) {
                 mddev->major_version = 1;
                 mddev->patch_version = 0;
@@ -877,13 +942,30 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                 memcpy(mddev->uuid, sb->set_uuid, 16);
 
                 mddev->max_disks =  (4096-256)/2;
-        } else {
-                __u64 ev1;
-                ev1 = le64_to_cpu(sb->events);
+
+                if ((le32_to_cpu(sb->feature_map) & 1) &&
+                    mddev->bitmap_file == NULL ) {
+                        if (mddev->level != 1) {
+                                printk(KERN_WARNING "md: bitmaps only supported for raid1\n");
+                                return -EINVAL;
+                        }
+                        mddev->bitmap_offset = (__s32)le32_to_cpu(sb->bitmap_offset);
+                }
+        } else if (mddev->pers == NULL) {
+                /* Insist of good event counter while assembling */
+                __u64 ev1 = le64_to_cpu(sb->events);
                 ++ev1;
                 if (ev1 < mddev->events)
                         return -EINVAL;
-        }
+        } else if (mddev->bitmap) {
+                /* If adding to array with a bitmap, then we can accept an
+                 * older device, but not too old.
+                 */
+                __u64 ev1 = le64_to_cpu(sb->events);
+                if (ev1 < mddev->bitmap->events_cleared)
+                        return 0;
+        } else /* just a hot-add of a new device, leave raid_disk at -1 */
+                return 0;
 
         if (mddev->level != LEVEL_MULTIPATH) {
                 int role;
@@ -891,14 +973,10 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                 role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
                 switch(role) {
                 case 0xffff: /* spare */
-                        rdev->in_sync = 0;
                         rdev->faulty = 0;
-                        rdev->raid_disk = -1;
                         break;
                 case 0xfffe: /* faulty */
-                        rdev->in_sync = 0;
                         rdev->faulty = 1;
-                        rdev->raid_disk = -1;
                         break;
                 default:
                         rdev->in_sync = 1;
@@ -906,7 +984,9 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                         rdev->raid_disk = role;
                         break;
                 }
-        }
+        } else /* MULTIPATH are always insync */
+                rdev->in_sync = 1;
+
         return 0;
 }
 
@@ -933,6 +1013,11 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
         else
                 sb->resync_offset = cpu_to_le64(0);
 
+        if (mddev->bitmap && mddev->bitmap_file == NULL) {
+                sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);
+                sb->feature_map = cpu_to_le32(1);
+        }
+
         max_dev = 0;
         ITERATE_RDEV(mddev,rdev2,tmp)
                 if (rdev2->desc_nr+1 > max_dev)
@@ -1196,8 +1281,11 @@ void md_print_devices(void)
         printk("md:     * <COMPLETE RAID STATE PRINTOUT> *\n");
         printk("md:     **********************************\n");
         ITERATE_MDDEV(mddev,tmp) {
-                printk("%s: ", mdname(mddev));
 
+                if (mddev->bitmap)
+                        bitmap_print_sb(mddev->bitmap);
+                else
+                        printk("%s: ", mdname(mddev));
                 ITERATE_RDEV(mddev,rdev,tmp2)
                         printk("<%s>", bdevname(rdev->bdev,b));
                 printk("\n");
@@ -1210,30 +1298,6 @@ void md_print_devices(void)
 }
 
 
-static int write_disk_sb(mdk_rdev_t * rdev)
-{
-        char b[BDEVNAME_SIZE];
-        if (!rdev->sb_loaded) {
-                MD_BUG();
-                return 1;
-        }
-        if (rdev->faulty) {
-                MD_BUG();
-                return 1;
-        }
-
-        dprintk(KERN_INFO "(write) %s's sb offset: %llu\n",
-                bdevname(rdev->bdev,b),
-               (unsigned long long)rdev->sb_offset);
-  
-        if (sync_page_io(rdev->bdev, rdev->sb_offset<<1, MD_SB_BYTES, rdev->sb_page, WRITE))
-                return 0;
-
-        printk("md: write_disk_sb failed for device %s\n", 
-                bdevname(rdev->bdev,b));
-        return 1;
-}
-
 static void sync_sbs(mddev_t * mddev)
 {
         mdk_rdev_t *rdev;
@@ -1248,12 +1312,14 @@ static void sync_sbs(mddev_t * mddev)
 
 static void md_update_sb(mddev_t * mddev)
 {
-        int err, count = 100;
+        int err;
         struct list_head *tmp;
         mdk_rdev_t *rdev;
+        int sync_req;
 
-        mddev->sb_dirty = 0;
 repeat:
+        spin_lock(&mddev->write_lock);
+        sync_req = mddev->in_sync;
         mddev->utime = get_seconds();
         mddev->events ++;
 
@@ -1266,20 +1332,26 @@ repeat:
                 MD_BUG();
                 mddev->events --;
         }
+        mddev->sb_dirty = 2;
         sync_sbs(mddev);
 
         /*
          * do not write anything to disk if using
          * nonpersistent superblocks
          */
-        if (!mddev->persistent)
+        if (!mddev->persistent) {
+                mddev->sb_dirty = 0;
+                spin_unlock(&mddev->write_lock);
+                wake_up(&mddev->sb_wait);
                 return;
+        }
+        spin_unlock(&mddev->write_lock);
 
         dprintk(KERN_INFO 
                 "md: updating %s RAID superblock on device (in sync %d)\n",
                 mdname(mddev),mddev->in_sync);
 
-        err = 0;
+        err = bitmap_update_sb(mddev->bitmap);
         ITERATE_RDEV(mddev,rdev,tmp) {
                 char b[BDEVNAME_SIZE];
                 dprintk(KERN_INFO "md: ");
@@ -1288,22 +1360,32 @@ repeat:
 
                 dprintk("%s ", bdevname(rdev->bdev,b));
                 if (!rdev->faulty) {
-                        err += write_disk_sb(rdev);
+                        md_super_write(mddev,rdev,
+                                       rdev->sb_offset<<1, MD_SB_BYTES,
+                                       rdev->sb_page);
+                        dprintk(KERN_INFO "(write) %s's sb offset: %llu\n",
+                                bdevname(rdev->bdev,b),
+                                (unsigned long long)rdev->sb_offset);
+
                 } else
                         dprintk(")\n");
-                if (!err && mddev->level == LEVEL_MULTIPATH)
+                if (mddev->level == LEVEL_MULTIPATH)
                         /* only need to write one superblock... */
                         break;
         }
-        if (err) {
-                if (--count) {
-                        printk(KERN_ERR "md: errors occurred during superblock"
-                                " update, repeating\n");
-                        goto repeat;
-                }
-                printk(KERN_ERR \
-                        "md: excessive errors occurred during superblock update, exiting\n");
+        wait_event(mddev->sb_wait, atomic_read(&mddev->pending_writes)==0);
+        /* if there was a failure, sb_dirty was set to 1, and we re-write super */
+
+        spin_lock(&mddev->write_lock);
+        if (mddev->in_sync != sync_req|| mddev->sb_dirty == 1) {
+                /* have to write it out again */
+                spin_unlock(&mddev->write_lock);
+                goto repeat;
         }
+        mddev->sb_dirty = 0;
+        spin_unlock(&mddev->write_lock);
+        wake_up(&mddev->sb_wait);
+
 }
 
 /*
@@ -1607,12 +1689,19 @@ static int do_md_run(mddev_t * mddev)
 
         mddev->resync_max_sectors = mddev->size << 1; /* may be over-ridden by personality */
 
-        err = mddev->pers->run(mddev);
+        /* before we start the array running, initialise the bitmap */
+        err = bitmap_create(mddev);
+        if (err)
+                printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
+                        mdname(mddev), err);
+        else
+                err = mddev->pers->run(mddev);
         if (err) {
                 printk(KERN_ERR "md: pers->run() failed ...\n");
                 module_put(mddev->pers->owner);
                 mddev->pers = NULL;
-                return -EINVAL;
+                bitmap_destroy(mddev);
+                return err;
         }
         atomic_set(&mddev->writes_pending,0);
         mddev->safemode = 0;
@@ -1725,6 +1814,14 @@ static int do_md_stop(mddev_t * mddev, int ro)
                 if (ro)
                         set_disk_ro(disk, 1);
         }
+
+        bitmap_destroy(mddev);
+        if (mddev->bitmap_file) {
+                atomic_set(&mddev->bitmap_file->f_dentry->d_inode->i_writecount, 1);
+                fput(mddev->bitmap_file);
+                mddev->bitmap_file = NULL;
+        }
+
         /*
          * Free resources if final stop
          */
@@ -1983,6 +2080,42 @@ static int get_array_info(mddev_t * mddev, void __user * arg)
         return 0;
 }
 
+static int get_bitmap_file(mddev_t * mddev, void * arg)
+{
+        mdu_bitmap_file_t *file = NULL; /* too big for stack allocation */
+        char *ptr, *buf = NULL;
+        int err = -ENOMEM;
+
+        file = kmalloc(sizeof(*file), GFP_KERNEL);
+        if (!file)
+                goto out;
+
+        /* bitmap disabled, zero the first byte and copy out */
+        if (!mddev->bitmap || !mddev->bitmap->file) {
+                file->pathname[0] = '\0';
+                goto copy_out;
+        }
+
+        buf = kmalloc(sizeof(file->pathname), GFP_KERNEL);
+        if (!buf)
+                goto out;
+
+        ptr = file_path(mddev->bitmap->file, buf, sizeof(file->pathname));
+        if (!ptr)
+                goto out;
+
+        strcpy(file->pathname, ptr);
+
+copy_out:
+        err = 0;
+        if (copy_to_user(arg, file, sizeof(*file)))
+                err = -EFAULT;
+out:
+        kfree(buf);
+        kfree(file);
+        return err;
+}
+
 static int get_disk_info(mddev_t * mddev, void __user * arg)
 {
         mdu_disk_info_t info;
@@ -2078,11 +2211,25 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
                                 PTR_ERR(rdev));
                         return PTR_ERR(rdev);
                 }
+                /* set save_raid_disk if appropriate */
+                if (!mddev->persistent) {
+                        if (info->state & (1<<MD_DISK_SYNC)  &&
+                            info->raid_disk < mddev->raid_disks)
+                                rdev->raid_disk = info->raid_disk;
+                        else
+                                rdev->raid_disk = -1;
+                } else
+                        super_types[mddev->major_version].
+                                validate_super(mddev, rdev);
+                rdev->saved_raid_disk = rdev->raid_disk;
+
                 rdev->in_sync = 0; /* just to be sure */
                 rdev->raid_disk = -1;
                 err = bind_rdev_to_array(rdev, mddev);
                 if (err)
                         export_rdev(rdev);
+
+                set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                 if (mddev->thread)
                         md_wakeup_thread(mddev->thread);
                 return err;
@@ -2256,6 +2403,49 @@ abort_export:
         return err;
 }
 
+/* similar to deny_write_access, but accounts for our holding a reference
+ * to the file ourselves */
+static int deny_bitmap_write_access(struct file * file)
+{
+        struct inode *inode = file->f_mapping->host;
+
+        spin_lock(&inode->i_lock);
+        if (atomic_read(&inode->i_writecount) > 1) {
+                spin_unlock(&inode->i_lock);
+                return -ETXTBSY;
+        }
+        atomic_set(&inode->i_writecount, -1);
+        spin_unlock(&inode->i_lock);
+
+        return 0;
+}
+
+static int set_bitmap_file(mddev_t *mddev, int fd)
+{
+        int err;
+
+        if (mddev->pers)
+                return -EBUSY;
+
+        mddev->bitmap_file = fget(fd);
+
+        if (mddev->bitmap_file == NULL) {
+                printk(KERN_ERR "%s: error: failed to get bitmap file\n",
+                        mdname(mddev));
+                return -EBADF;
+        }
+
+        err = deny_bitmap_write_access(mddev->bitmap_file);
+        if (err) {
+                printk(KERN_ERR "%s: error: bitmap file is already in use\n",
+                        mdname(mddev));
+                fput(mddev->bitmap_file);
+                mddev->bitmap_file = NULL;
+        } else
+                mddev->bitmap_offset = 0; /* file overrides offset */
+        return err;
+}
+
 /*
  * set_array_info is used two different ways
  * The original usage is when creating a new array.
@@ -2567,8 +2757,10 @@ static int md_ioctl(struct inode *inode, struct file *file,
         /*
          * Commands querying/configuring an existing array:
          */
-        /* if we are initialised yet, only ADD_NEW_DISK or STOP_ARRAY is allowed */
-        if (!mddev->raid_disks && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY && cmd != RUN_ARRAY) {
+        /* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
+         * RUN_ARRAY, and SET_BITMAP_FILE are allowed */
+        if (!mddev->raid_disks && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
+                        && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE) {
                 err = -ENODEV;
                 goto abort_unlock;
         }
@@ -2582,6 +2774,10 @@ static int md_ioctl(struct inode *inode, struct file *file,
                         err = get_array_info(mddev, argp);
                         goto done_unlock;
 
+                case GET_BITMAP_FILE:
+                        err = get_bitmap_file(mddev, (void *)arg);
+                        goto done_unlock;
+
                 case GET_DISK_INFO:
                         err = get_disk_info(mddev, argp);
                         goto done_unlock;
@@ -2662,6 +2858,10 @@ static int md_ioctl(struct inode *inode, struct file *file,
                         err = do_md_run (mddev);
                         goto done_unlock;
 
+                case SET_BITMAP_FILE:
+                        err = set_bitmap_file(mddev, (int)arg);
+                        goto done_unlock;
+
                 default:
                         if (_IOC_TYPE(cmd) == MD_MAJOR)
                                 printk(KERN_WARNING "md: %s(pid %d) used"
@@ -2773,8 +2973,9 @@ static int md_thread(void * arg)
         while (thread->run) {
                 void (*run)(mddev_t *);
 
-                wait_event_interruptible(thread->wqueue,
-                                         test_bit(THREAD_WAKEUP, &thread->flags));
+                wait_event_interruptible_timeout(thread->wqueue,
+                                                 test_bit(THREAD_WAKEUP, &thread->flags),
+                                                 thread->timeout);
                 if (current->flags & PF_FREEZE)
                         refrigerator(PF_FREEZE);
 
@@ -2820,6 +3021,7 @@ mdk_thread_t *md_register_thread(void (*run) (mddev_t *), mddev_t *mddev,
         thread->run = run;
         thread->mddev = mddev;
         thread->name = name;
+        thread->timeout = MAX_SCHEDULE_TIMEOUT;
         ret = kernel_thread(md_thread, thread, 0);
         if (ret < 0) {
                 kfree(thread);
@@ -2858,13 +3060,13 @@ void md_error(mddev_t *mddev, mdk_rdev_t *rdev)
 
         if (!rdev || rdev->faulty)
                 return;
-
+/*
         dprintk("md_error dev:%s, rdev:(%d:%d), (caller: %p,%p,%p,%p).\n",
                 mdname(mddev),
                 MAJOR(rdev->bdev->bd_dev), MINOR(rdev->bdev->bd_dev),
                 __builtin_return_address(0),__builtin_return_address(1),
                 __builtin_return_address(2),__builtin_return_address(3));
-
+*/
         if (!mddev->pers->error_handler)
                 return;
         mddev->pers->error_handler(mddev,rdev);
@@ -3018,6 +3220,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
         struct list_head *tmp2;
         mdk_rdev_t *rdev;
         int i;
+        struct bitmap *bitmap;
 
         if (v == (void*)1) {
                 seq_printf(seq, "Personalities : ");
@@ -3070,10 +3273,35 @@ static int md_seq_show(struct seq_file *seq, void *v)
                 if (mddev->pers) {
                         mddev->pers->status (seq, mddev);
                         seq_printf(seq, "\n      ");
-                        if (mddev->curr_resync > 2)
+                        if (mddev->curr_resync > 2) {
                                 status_resync (seq, mddev);
-                        else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
-                                seq_printf(seq, "       resync=DELAYED");
+                                seq_printf(seq, "\n      ");
+                        } else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
+                                seq_printf(seq, "       resync=DELAYED\n      ");
+                } else
+                        seq_printf(seq, "\n       ");
+
+                if ((bitmap = mddev->bitmap)) {
+                        unsigned long chunk_kb;
+                        unsigned long flags;
+                        spin_lock_irqsave(&bitmap->lock, flags);
+                        chunk_kb = bitmap->chunksize >> 10;
+                        seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
+                                "%lu%s chunk",
+                                bitmap->pages - bitmap->missing_pages,
+                                bitmap->pages,
+                                (bitmap->pages - bitmap->missing_pages)
+                                        << (PAGE_SHIFT - 10),
+                                chunk_kb ? chunk_kb : bitmap->chunksize,
+                                chunk_kb ? "KB" : "B");
+                        if (bitmap->file) {
+                                seq_printf(seq, ", file: ");
+                                seq_path(seq, bitmap->file->f_vfsmnt,
+                                         bitmap->file->f_dentry," \t\n");
+                        }
+
+                        seq_printf(seq, "\n");
+                        spin_unlock_irqrestore(&bitmap->lock, flags);
                 }
 
                 seq_printf(seq, "\n");
@@ -3176,19 +3404,28 @@ void md_done_sync(mddev_t *mddev, int blocks, int ok)
 }
 
 
-void md_write_start(mddev_t *mddev)
+/* md_write_start(mddev, bi)
+ * If we need to update some array metadata (e.g. 'active' flag
+ * in superblock) before writing, schedule a superblock update
+ * and wait for it to complete.
+ */
+void md_write_start(mddev_t *mddev, struct bio *bi)
 {
-        if (!atomic_read(&mddev->writes_pending)) {
-                mddev_lock_uninterruptible(mddev);
+        DEFINE_WAIT(w);
+        if (bio_data_dir(bi) != WRITE)
+                return;
+
+        atomic_inc(&mddev->writes_pending);
+        if (mddev->in_sync) {
+                spin_lock(&mddev->write_lock);
                 if (mddev->in_sync) {
                         mddev->in_sync = 0;
-                        del_timer(&mddev->safemode_timer);
-                        md_update_sb(mddev);
+                        mddev->sb_dirty = 1;
+                        md_wakeup_thread(mddev->thread);
                 }
-                atomic_inc(&mddev->writes_pending);
-                mddev_unlock(mddev);
-        } else
-                atomic_inc(&mddev->writes_pending);
+                spin_unlock(&mddev->write_lock);
+        }
+        wait_event(mddev->sb_wait, mddev->sb_dirty==0);
 }
 
 void md_write_end(mddev_t *mddev)
@@ -3201,37 +3438,6 @@ void md_write_end(mddev_t *mddev)
         }
 }
 
-static inline void md_enter_safemode(mddev_t *mddev)
-{
-        if (!mddev->safemode) return;
-        if (mddev->safemode == 2 &&
-            (atomic_read(&mddev->writes_pending) || mddev->in_sync ||
-                    mddev->recovery_cp != MaxSector))
-                return; /* avoid the lock */
-        mddev_lock_uninterruptible(mddev);
-        if (mddev->safemode && !atomic_read(&mddev->writes_pending) &&
-            !mddev->in_sync && mddev->recovery_cp == MaxSector) {
-                mddev->in_sync = 1;
-                md_update_sb(mddev);
-        }
-        mddev_unlock(mddev);
-
-        if (mddev->safemode == 1)
-                mddev->safemode = 0;
-}
-
-void md_handle_safemode(mddev_t *mddev)
-{
-        if (signal_pending(current)) {
-                printk(KERN_INFO "md: %s in immediate safe mode\n",
-                        mdname(mddev));
-                mddev->safemode = 2;
-                flush_signals(current);
-        }
-        md_enter_safemode(mddev);
-}
-
-
 static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
 
 #define SYNC_MARKS      10
@@ -3241,12 +3447,13 @@ static void md_do_sync(mddev_t *mddev)
         mddev_t *mddev2;
         unsigned int currspeed = 0,
                  window;
-        sector_t max_sectors,j;
+        sector_t max_sectors,j, io_sectors;
         unsigned long mark[SYNC_MARKS];
         sector_t mark_cnt[SYNC_MARKS];
         int last_mark,m;
         struct list_head *tmp;
         sector_t last_check;
+        int skipped = 0;
 
         /* just incase thread restarts... */
         if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
@@ -3312,7 +3519,7 @@ static void md_do_sync(mddev_t *mddev)
 
         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
                 /* resync follows the size requested by the personality,
-                 * which default to physical size, but can be virtual size
+                 * which defaults to physical size, but can be virtual size
                  */
                 max_sectors = mddev->resync_max_sectors;
         else
@@ -3327,13 +3534,15 @@ static void md_do_sync(mddev_t *mddev)
                sysctl_speed_limit_max);
 
         is_mddev_idle(mddev); /* this also initializes IO event counters */
-        if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
+        /* we don't use the checkpoint if there's a bitmap */
+        if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && !mddev->bitmap)
                 j = mddev->recovery_cp;
         else
                 j = 0;
+        io_sectors = 0;
         for (m = 0; m < SYNC_MARKS; m++) {
                 mark[m] = jiffies;
-                mark_cnt[m] = j;
+                mark_cnt[m] = io_sectors;
         }
         last_mark = 0;
         mddev->resync_mark = mark[last_mark];
@@ -3358,21 +3567,29 @@ static void md_do_sync(mddev_t *mddev)
         }
 
         while (j < max_sectors) {
-                int sectors;
+                sector_t sectors;
 
-                sectors = mddev->pers->sync_request(mddev, j, currspeed < sysctl_speed_limit_min);
-                if (sectors < 0) {
+                skipped = 0;
+                sectors = mddev->pers->sync_request(mddev, j, &skipped,
+                                            currspeed < sysctl_speed_limit_min);
+                if (sectors == 0) {
                         set_bit(MD_RECOVERY_ERR, &mddev->recovery);
                         goto out;
                 }
-                atomic_add(sectors, &mddev->recovery_active);
+
+                if (!skipped) { /* actual IO requested */
+                        io_sectors += sectors;
+                        atomic_add(sectors, &mddev->recovery_active);
+                }
+
                 j += sectors;
                 if (j>1) mddev->curr_resync = j;
 
-                if (last_check + window > j || j == max_sectors)
+
+                if (last_check + window > io_sectors || j == max_sectors)
                         continue;
 
-                last_check = j;
+                last_check = io_sectors;
 
                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery) ||
                     test_bit(MD_RECOVERY_ERR, &mddev->recovery))
@@ -3386,7 +3603,7 @@ static void md_do_sync(mddev_t *mddev)
                         mddev->resync_mark = mark[next];
                         mddev->resync_mark_cnt = mark_cnt[next];
                         mark[next] = jiffies;
-                        mark_cnt[next] = j - atomic_read(&mddev->recovery_active);
+                        mark_cnt[next] = io_sectors - atomic_read(&mddev->recovery_active);
                         last_mark = next;
                 }
 
@@ -3413,7 +3630,8 @@ static void md_do_sync(mddev_t *mddev)
                 mddev->queue->unplug_fn(mddev->queue);
                 cond_resched();
 
-                currspeed = ((unsigned long)(j-mddev->resync_mark_cnt))/2/((jiffies-mddev->resync_mark)/HZ +1) +1;
+                currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
+                        /((jiffies-mddev->resync_mark)/HZ +1) +1;
 
                 if (currspeed > sysctl_speed_limit_min) {
                         if ((currspeed > sysctl_speed_limit_max) ||
@@ -3433,7 +3651,7 @@ static void md_do_sync(mddev_t *mddev)
         wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
 
         /* tell personality that we are finished */
-        mddev->pers->sync_request(mddev, max_sectors, 1);
+        mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
 
         if (!test_bit(MD_RECOVERY_ERR, &mddev->recovery) &&
             mddev->curr_resync > 2 &&
@@ -3447,7 +3665,6 @@ static void md_do_sync(mddev_t *mddev)
                         mddev->recovery_cp = MaxSector;
         }
 
-        md_enter_safemode(mddev);
  skip:
         mddev->curr_resync = 0;
         wake_up(&resync_wait);
@@ -3484,20 +3701,48 @@ void md_check_recovery(mddev_t *mddev)
         struct list_head *rtmp;
 
 
-        dprintk(KERN_INFO "md: recovery thread got woken up ...\n");
+        if (mddev->bitmap)
+                bitmap_daemon_work(mddev->bitmap);
 
         if (mddev->ro)
                 return;
+
+        if (signal_pending(current)) {
+                if (mddev->pers->sync_request) {
+                        printk(KERN_INFO "md: %s in immediate safe mode\n",
+                               mdname(mddev));
+                        mddev->safemode = 2;
+                }
+                flush_signals(current);
+        }
+
         if ( ! (
                 mddev->sb_dirty ||
                 test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
-                test_bit(MD_RECOVERY_DONE, &mddev->recovery)
+                test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
+                (mddev->safemode == 1) ||
+                (mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending)
+                 && !mddev->in_sync && mddev->recovery_cp == MaxSector)
                 ))
                 return;
+
         if (mddev_trylock(mddev)==0) {
                 int spares =0;
+
+                spin_lock(&mddev->write_lock);
+                if (mddev->safemode && !atomic_read(&mddev->writes_pending) &&
+                    !mddev->in_sync && mddev->recovery_cp == MaxSector) {
+                        mddev->in_sync = 1;
+                        mddev->sb_dirty = 1;
+                }
+                if (mddev->safemode == 1)
+                        mddev->safemode = 0;
+                spin_unlock(&mddev->write_lock);
+
                 if (mddev->sb_dirty)
                         md_update_sb(mddev);
+
+
                 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
                     !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
                         /* resync/recovery still happening */
@@ -3515,6 +3760,14 @@ void md_check_recovery(mddev_t *mddev)
                                 mddev->pers->spare_active(mddev);
                         }
                         md_update_sb(mddev);
+
+                        /* if array is no-longer degraded, then any saved_raid_disk
+                         * information must be scrapped
+                         */
+                        if (!mddev->degraded)
+                                ITERATE_RDEV(mddev,rdev,rtmp)
+                                        rdev->saved_raid_disk = -1;
+
                         mddev->recovery = 0;
                         /* flag recovery needed just to double check */
                         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
@@ -3557,6 +3810,13 @@ void md_check_recovery(mddev_t *mddev)
                         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
                         if (!spares)
                                 set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+                        if (spares && mddev->bitmap && ! mddev->bitmap->file) {
+                                /* We are adding a device or devices to an array
+                                 * which has the bitmap stored on all devices.
+                                 * So make sure all bitmap pages get written
+                                 */
+                                bitmap_write_all(mddev->bitmap);
+                        }
                         mddev->sync_thread = md_register_thread(md_do_sync,
                                                                 mddev,
                                                                 "%s_resync");
@@ -3624,6 +3884,8 @@ static int __init md_init(void)
                         " MD_SB_DISKS=%d\n",
                         MD_MAJOR_VERSION, MD_MINOR_VERSION,
                         MD_PATCHLEVEL_VERSION, MAX_MD_DEVS, MD_SB_DISKS);
+        printk(KERN_INFO "md: bitmap version %d.%d\n", BITMAP_MAJOR,
+                        BITMAP_MINOR);
 
         if (register_blkdev(MAJOR_NR, "md"))
                 return -1;
@@ -3739,7 +4001,6 @@ EXPORT_SYMBOL(md_error);
 EXPORT_SYMBOL(md_done_sync);
 EXPORT_SYMBOL(md_write_start);
 EXPORT_SYMBOL(md_write_end);
-EXPORT_SYMBOL(md_handle_safemode);
 EXPORT_SYMBOL(md_register_thread);
 EXPORT_SYMBOL(md_unregister_thread);
 EXPORT_SYMBOL(md_wakeup_thread);
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 4e4bfde3db5d..2d2ca7fa0265 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -462,10 +462,6 @@ static int multipath_run (mddev_t *mddev)
         }
         memset(conf->multipaths, 0, sizeof(struct multipath_info)*mddev->raid_disks);
 
-        mddev->queue->unplug_fn = multipath_unplug;
-
-        mddev->queue->issue_flush_fn = multipath_issue_flush;
-
         conf->working_disks = 0;
         ITERATE_RDEV(mddev,rdev,tmp) {
                 disk_idx = rdev->raid_disk;
@@ -528,13 +524,16 @@ static int multipath_run (mddev_t *mddev)
          * Ok, everything is just fine now
          */
         mddev->array_size = mddev->size;
+
+        mddev->queue->unplug_fn = multipath_unplug;
+        mddev->queue->issue_flush_fn = multipath_issue_flush;
+
         return 0;
 
 out_free_conf:
         if (conf->pool)
                 mempool_destroy(conf->pool);
-        if (conf->multipaths)
-                kfree(conf->multipaths);
+        kfree(conf->multipaths);
         kfree(conf);
         mddev->private = NULL;
 out:
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index e7d934eca06f..e11dd14d0b43 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -371,10 +371,8 @@ static int raid0_run (mddev_t *mddev)
         return 0;
 
 out_free_conf:
-        if (conf->strip_zone)
-                kfree(conf->strip_zone);
-        if (conf->devlist)
-                kfree (conf->devlist);
+        kfree(conf->strip_zone);
+        kfree(conf->devlist);
         kfree(conf);
         mddev->private = NULL;
 out:
@@ -386,11 +384,11 @@ static int raid0_stop (mddev_t *mddev)
         raid0_conf_t *conf = mddev_to_conf(mddev);
 
         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
-        kfree (conf->hash_table);
+        kfree(conf->hash_table);
         conf->hash_table = NULL;
-        kfree (conf->strip_zone);
+        kfree(conf->strip_zone);
         conf->strip_zone = NULL;
-        kfree (conf);
+        kfree(conf);
         mddev->private = NULL;
 
         return 0;
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 83380b5d6593..ff1dbec864af 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -12,6 +12,15 @@
  * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
  * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
  *
+ * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
+ * bitmapped intelligence in resync:
+ *
+ *      - bitmap marked during normal i/o
+ *      - bitmap used to skip nondirty blocks during sync
+ *
+ * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
+ * - persistent bitmap code
+ *
  * 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)
@@ -22,7 +31,16 @@
  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include "dm-bio-list.h"
 #include <linux/raid/raid1.h>
+#include <linux/raid/bitmap.h>
+
+#define DEBUG 0
+#if DEBUG
+#define PRINTK(x...) printk(x)
+#else
+#define PRINTK(x...)
+#endif
 
 /*
  * Number of guaranteed r1bios in case of extreme VM load:
@@ -287,9 +305,11 @@ static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int
         /*
          * this branch is our 'one mirror IO has finished' event handler:
          */
-        if (!uptodate)
+        if (!uptodate) {
                 md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
-        else
+                /* an I/O failed, we can't clear the bitmap */
+                set_bit(R1BIO_Degraded, &r1_bio->state);
+        } else
                 /*
                  * Set R1BIO_Uptodate in our master bio, so that
                  * we will return a good error code for to the higher
@@ -309,6 +329,10 @@ static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int
          * already.
          */
         if (atomic_dec_and_test(&r1_bio->remaining)) {
+                /* clear the bitmap if all writes complete successfully */
+                bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
+                                r1_bio->sectors,
+                                !test_bit(R1BIO_Degraded, &r1_bio->state));
                 md_write_end(r1_bio->mddev);
                 raid_end_bio_io(r1_bio);
         }
@@ -458,7 +482,10 @@ static void unplug_slaves(mddev_t *mddev)
 
 static void raid1_unplug(request_queue_t *q)
 {
-        unplug_slaves(q->queuedata);
+        mddev_t *mddev = q->queuedata;
+
+        unplug_slaves(mddev);
+        md_wakeup_thread(mddev->thread);
 }
 
 static int raid1_issue_flush(request_queue_t *q, struct gendisk *disk,
@@ -501,16 +528,16 @@ static void device_barrier(conf_t *conf, sector_t sect)
 {
         spin_lock_irq(&conf->resync_lock);
         wait_event_lock_irq(conf->wait_idle, !waitqueue_active(&conf->wait_resume),
-                            conf->resync_lock, unplug_slaves(conf->mddev));
+                            conf->resync_lock, raid1_unplug(conf->mddev->queue));
         
         if (!conf->barrier++) {
                 wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
-                                    conf->resync_lock, unplug_slaves(conf->mddev));
+                                    conf->resync_lock, raid1_unplug(conf->mddev->queue));
                 if (conf->nr_pending)
                         BUG();
         }
         wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH,
-                            conf->resync_lock, unplug_slaves(conf->mddev));
+                            conf->resync_lock, raid1_unplug(conf->mddev->queue));
         conf->next_resync = sect;
         spin_unlock_irq(&conf->resync_lock);
 }
@@ -522,14 +549,20 @@ static int make_request(request_queue_t *q, struct bio * bio)
         mirror_info_t *mirror;
         r1bio_t *r1_bio;
         struct bio *read_bio;
-        int i, disks;
+        int i, targets = 0, disks;
         mdk_rdev_t *rdev;
+        struct bitmap *bitmap = mddev->bitmap;
+        unsigned long flags;
+        struct bio_list bl;
+
 
         /*
          * Register the new request and wait if the reconstruction
          * thread has put up a bar for new requests.
          * Continue immediately if no resync is active currently.
          */
+        md_write_start(mddev, bio); /* wait on superblock update early */
+
         spin_lock_irq(&conf->resync_lock);
         wait_event_lock_irq(conf->wait_resume, !conf->barrier, conf->resync_lock, );
         conf->nr_pending++;
@@ -552,7 +585,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
 
         r1_bio->master_bio = bio;
         r1_bio->sectors = bio->bi_size >> 9;
-
+        r1_bio->state = 0;
         r1_bio->mddev = mddev;
         r1_bio->sector = bio->bi_sector;
 
@@ -595,6 +628,13 @@ static int make_request(request_queue_t *q, struct bio * bio)
          * bios[x] to bio
          */
         disks = conf->raid_disks;
+#if 0
+        { static int first=1;
+        if (first) printk("First Write sector %llu disks %d\n",
+                          (unsigned long long)r1_bio->sector, disks);
+        first = 0;
+        }
+#endif
         rcu_read_lock();
         for (i = 0;  i < disks; i++) {
                 if ((rdev=conf->mirrors[i].rdev) != NULL &&
@@ -605,13 +645,21 @@ static int make_request(request_queue_t *q, struct bio * bio)
                                 r1_bio->bios[i] = NULL;
                         } else
                                 r1_bio->bios[i] = bio;
+                        targets++;
                 } else
                         r1_bio->bios[i] = NULL;
         }
         rcu_read_unlock();
 
-        atomic_set(&r1_bio->remaining, 1);
-        md_write_start(mddev);
+        if (targets < conf->raid_disks) {
+                /* array is degraded, we will not clear the bitmap
+                 * on I/O completion (see raid1_end_write_request) */
+                set_bit(R1BIO_Degraded, &r1_bio->state);
+        }
+
+        atomic_set(&r1_bio->remaining, 0);
+
+        bio_list_init(&bl);
         for (i = 0; i < disks; i++) {
                 struct bio *mbio;
                 if (!r1_bio->bios[i])
@@ -627,14 +675,23 @@ static int make_request(request_queue_t *q, struct bio * bio)
                 mbio->bi_private = r1_bio;
 
                 atomic_inc(&r1_bio->remaining);
-                generic_make_request(mbio);
-        }
 
-        if (atomic_dec_and_test(&r1_bio->remaining)) {
-                md_write_end(mddev);
-                raid_end_bio_io(r1_bio);
+                bio_list_add(&bl, mbio);
         }
 
+        bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors);
+        spin_lock_irqsave(&conf->device_lock, flags);
+        bio_list_merge(&conf->pending_bio_list, &bl);
+        bio_list_init(&bl);
+
+        blk_plug_device(mddev->queue);
+        spin_unlock_irqrestore(&conf->device_lock, flags);
+
+#if 0
+        while ((bio = bio_list_pop(&bl)) != NULL)
+                generic_make_request(bio);
+#endif
+
         return 0;
 }
 
@@ -714,7 +771,7 @@ static void close_sync(conf_t *conf)
 {
         spin_lock_irq(&conf->resync_lock);
         wait_event_lock_irq(conf->wait_resume, !conf->barrier,
-                            conf->resync_lock,  unplug_slaves(conf->mddev));
+                            conf->resync_lock,  raid1_unplug(conf->mddev->queue));
         spin_unlock_irq(&conf->resync_lock);
 
         if (conf->barrier) BUG();
@@ -754,9 +811,12 @@ static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
         conf_t *conf = mddev->private;
         int found = 0;
-        int mirror;
+        int mirror = 0;
         mirror_info_t *p;
 
+        if (rdev->saved_raid_disk >= 0 &&
+            conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
+                mirror = rdev->saved_raid_disk;
         for (mirror=0; mirror < mddev->raid_disks; mirror++)
                 if ( !(p=conf->mirrors+mirror)->rdev) {
 
@@ -773,6 +833,8 @@ static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                         p->head_position = 0;
                         rdev->raid_disk = mirror;
                         found = 1;
+                        if (rdev->saved_raid_disk != mirror)
+                                conf->fullsync = 1;
                         p->rdev = rdev;
                         break;
                 }
@@ -828,10 +890,11 @@ static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
          * or re-read if the read failed.
          * We don't do much here, just schedule handling by raid1d
          */
-        if (!uptodate)
+        if (!uptodate) {
                 md_error(r1_bio->mddev,
                          conf->mirrors[r1_bio->read_disk].rdev);
-        else
+                set_bit(R1BIO_Degraded, &r1_bio->state);
+        } else
                 set_bit(R1BIO_Uptodate, &r1_bio->state);
         rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
         reschedule_retry(r1_bio);
@@ -855,8 +918,10 @@ static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
                         mirror = i;
                         break;
                 }
-        if (!uptodate)
+        if (!uptodate) {
                 md_error(mddev, conf->mirrors[mirror].rdev);
+                set_bit(R1BIO_Degraded, &r1_bio->state);
+        }
         update_head_pos(mirror, r1_bio);
 
         if (atomic_dec_and_test(&r1_bio->remaining)) {
@@ -876,6 +941,9 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
 
         bio = r1_bio->bios[r1_bio->read_disk];
 
+/*
+        if (r1_bio->sector == 0) printk("First sync write startss\n");
+*/
         /*
          * schedule writes
          */
@@ -903,10 +971,12 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
                 atomic_inc(&conf->mirrors[i].rdev->nr_pending);
                 atomic_inc(&r1_bio->remaining);
                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
+
                 generic_make_request(wbio);
         }
 
         if (atomic_dec_and_test(&r1_bio->remaining)) {
+                /* if we're here, all write(s) have completed, so clean up */
                 md_done_sync(mddev, r1_bio->sectors, 1);
                 put_buf(r1_bio);
         }
@@ -931,11 +1001,30 @@ static void raid1d(mddev_t *mddev)
         mdk_rdev_t *rdev;
 
         md_check_recovery(mddev);
-        md_handle_safemode(mddev);
         
         for (;;) {
                 char b[BDEVNAME_SIZE];
                 spin_lock_irqsave(&conf->device_lock, flags);
+
+                if (conf->pending_bio_list.head) {
+                        bio = bio_list_get(&conf->pending_bio_list);
+                        blk_remove_plug(mddev->queue);
+                        spin_unlock_irqrestore(&conf->device_lock, flags);
+                        /* flush any pending bitmap writes to disk before proceeding w/ I/O */
+                        if (bitmap_unplug(mddev->bitmap) != 0)
+                                printk("%s: bitmap file write failed!\n", mdname(mddev));
+
+                        while (bio) { /* submit pending writes */
+                                struct bio *next = bio->bi_next;
+                                bio->bi_next = NULL;
+                                generic_make_request(bio);
+                                bio = next;
+                        }
+                        unplug = 1;
+
+                        continue;
+                }
+
                 if (list_empty(head))
                         break;
                 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
@@ -1009,7 +1098,7 @@ static int init_resync(conf_t *conf)
  * that can be installed to exclude normal IO requests.
  */
 
-static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
+static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
 {
         conf_t *conf = mddev_to_conf(mddev);
         mirror_info_t *mirror;
@@ -1019,17 +1108,43 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
         int disk;
         int i;
         int write_targets = 0;
+        int sync_blocks;
 
         if (!conf->r1buf_pool)
+        {
+/*
+                printk("sync start - bitmap %p\n", mddev->bitmap);
+*/
                 if (init_resync(conf))
-                        return -ENOMEM;
+                        return 0;
+        }
 
         max_sector = mddev->size << 1;
         if (sector_nr >= max_sector) {
+                /* If we aborted, we need to abort the
+                 * sync on the 'current' bitmap chunk (there will
+                 * only be one in raid1 resync.
+                 * We can find the current addess in mddev->curr_resync
+                 */
+                if (!conf->fullsync) {
+                        if (mddev->curr_resync < max_sector)
+                                bitmap_end_sync(mddev->bitmap,
+                                                mddev->curr_resync,
+                                                &sync_blocks, 1);
+                        bitmap_close_sync(mddev->bitmap);
+                }
+                if (mddev->curr_resync >= max_sector)
+                        conf->fullsync = 0;
                 close_sync(conf);
                 return 0;
         }
 
+        if (!conf->fullsync &&
+            !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks)) {
+                /* We can skip this block, and probably several more */
+                *skipped = 1;
+                return sync_blocks;
+        }
         /*
          * If there is non-resync activity waiting for us then
          * put in a delay to throttle resync.
@@ -1068,6 +1183,7 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
 
         r1_bio->mddev = mddev;
         r1_bio->sector = sector_nr;
+        r1_bio->state = 0;
         set_bit(R1BIO_IsSync, &r1_bio->state);
         r1_bio->read_disk = disk;
 
@@ -1102,18 +1218,24 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
                 bio->bi_bdev = conf->mirrors[i].rdev->bdev;
                 bio->bi_private = r1_bio;
         }
+
+        if (write_targets + 1 < conf->raid_disks)
+                /* array degraded, can't clear bitmap */
+                set_bit(R1BIO_Degraded, &r1_bio->state);
+
         if (write_targets == 0) {
                 /* There is nowhere to write, so all non-sync
                  * drives must be failed - so we are finished
                  */
-                int rv = max_sector - sector_nr;
-                md_done_sync(mddev, rv, 1);
+                sector_t rv = max_sector - sector_nr;
+                *skipped = 1;
                 put_buf(r1_bio);
                 rdev_dec_pending(conf->mirrors[disk].rdev, mddev);
                 return rv;
         }
 
         nr_sectors = 0;
+        sync_blocks = 0;
         do {
                 struct page *page;
                 int len = PAGE_SIZE;
@@ -1121,6 +1243,17 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
                         len = (max_sector - sector_nr) << 9;
                 if (len == 0)
                         break;
+                if (!conf->fullsync) {
+                        if (sync_blocks == 0) {
+                                if (!bitmap_start_sync(mddev->bitmap,
+                                                       sector_nr, &sync_blocks))
+                                        break;
+                                if (sync_blocks < (PAGE_SIZE>>9))
+                                        BUG();
+                                if (len > (sync_blocks<<9)) len = sync_blocks<<9;
+                        }
+                }
+
                 for (i=0 ; i < conf->raid_disks; i++) {
                         bio = r1_bio->bios[i];
                         if (bio->bi_end_io) {
@@ -1143,6 +1276,7 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
                 }
                 nr_sectors += len>>9;
                 sector_nr += len>>9;
+                sync_blocks -= (len>>9);
         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
  bio_full:
         bio = r1_bio->bios[disk];
@@ -1197,10 +1331,6 @@ static int run(mddev_t *mddev)
         if (!conf->r1bio_pool)
                 goto out_no_mem;
 
-        mddev->queue->unplug_fn = raid1_unplug;
-
-        mddev->queue->issue_flush_fn = raid1_issue_flush;
-
         ITERATE_RDEV(mddev, rdev, tmp) {
                 disk_idx = rdev->raid_disk;
                 if (disk_idx >= mddev->raid_disks
@@ -1235,6 +1365,9 @@ static int run(mddev_t *mddev)
         init_waitqueue_head(&conf->wait_idle);
         init_waitqueue_head(&conf->wait_resume);
 
+        bio_list_init(&conf->pending_bio_list);
+        bio_list_init(&conf->flushing_bio_list);
+
         if (!conf->working_disks) {
                 printk(KERN_ERR "raid1: no operational mirrors for %s\n",
                         mdname(mddev));
@@ -1263,16 +1396,15 @@ static int run(mddev_t *mddev)
         conf->last_used = j;
 
 
-
-        {
-                mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
-                if (!mddev->thread) {
-                        printk(KERN_ERR 
-                                "raid1: couldn't allocate thread for %s\n", 
-                                mdname(mddev));
-                        goto out_free_conf;
-                }
+        mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
+        if (!mddev->thread) {
+                printk(KERN_ERR
+                       "raid1: couldn't allocate thread for %s\n",
+                       mdname(mddev));
+                goto out_free_conf;
         }
+        if (mddev->bitmap) mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
+
         printk(KERN_INFO 
                 "raid1: raid set %s active with %d out of %d mirrors\n",
                 mdname(mddev), mddev->raid_disks - mddev->degraded, 
@@ -1282,6 +1414,9 @@ static int run(mddev_t *mddev)
          */
         mddev->array_size = mddev->size;
 
+        mddev->queue->unplug_fn = raid1_unplug;
+        mddev->queue->issue_flush_fn = raid1_issue_flush;
+
         return 0;
 
 out_no_mem:
@@ -1292,10 +1427,8 @@ out_free_conf:
         if (conf) {
                 if (conf->r1bio_pool)
                         mempool_destroy(conf->r1bio_pool);
-                if (conf->mirrors)
-                        kfree(conf->mirrors);
-                if (conf->poolinfo)
-                        kfree(conf->poolinfo);
+                kfree(conf->mirrors);
+                kfree(conf->poolinfo);
                 kfree(conf);
                 mddev->private = NULL;
         }
@@ -1312,10 +1445,8 @@ static int stop(mddev_t *mddev)
         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
         if (conf->r1bio_pool)
                 mempool_destroy(conf->r1bio_pool);
-        if (conf->mirrors)
-                kfree(conf->mirrors);
-        if (conf->poolinfo)
-                kfree(conf->poolinfo);
+        kfree(conf->mirrors);
+        kfree(conf->poolinfo);
         kfree(conf);
         mddev->private = NULL;
         return 0;
@@ -1350,17 +1481,26 @@ static int raid1_reshape(mddev_t *mddev, int raid_disks)
          * We allocate a new r1bio_pool if we can.
          * Then raise a device barrier and wait until all IO stops.
          * Then resize conf->mirrors and swap in the new r1bio pool.
+         *
+         * At the same time, we "pack" the devices so that all the missing
+         * devices have the higher raid_disk numbers.
          */
         mempool_t *newpool, *oldpool;
         struct pool_info *newpoolinfo;
         mirror_info_t *newmirrors;
         conf_t *conf = mddev_to_conf(mddev);
+        int cnt;
 
-        int d;
+        int d, d2;
 
-        for (d= raid_disks; d < conf->raid_disks; d++)
-                if (conf->mirrors[d].rdev)
+        if (raid_disks < conf->raid_disks) {
+                cnt=0;
+                for (d= 0; d < conf->raid_disks; d++)
+                        if (conf->mirrors[d].rdev)
+                                cnt++;
+                if (cnt > raid_disks)
                         return -EBUSY;
+        }
 
         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
         if (!newpoolinfo)
@@ -1385,14 +1525,18 @@ static int raid1_reshape(mddev_t *mddev, int raid_disks)
         spin_lock_irq(&conf->resync_lock);
         conf->barrier++;
         wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
-                            conf->resync_lock, unplug_slaves(mddev));
+                            conf->resync_lock, raid1_unplug(mddev->queue));
         spin_unlock_irq(&conf->resync_lock);
 
         /* ok, everything is stopped */
         oldpool = conf->r1bio_pool;
         conf->r1bio_pool = newpool;
-        for (d=0; d < raid_disks && d < conf->raid_disks; d++)
-                newmirrors[d] = conf->mirrors[d];
+
+        for (d=d2=0; d < conf->raid_disks; d++)
+                if (conf->mirrors[d].rdev) {
+                        conf->mirrors[d].rdev->raid_disk = d2;
+                        newmirrors[d2++].rdev = conf->mirrors[d].rdev;
+                }
         kfree(conf->mirrors);
         conf->mirrors = newmirrors;
         kfree(conf->poolinfo);
@@ -1401,6 +1545,7 @@ static int raid1_reshape(mddev_t *mddev, int raid_disks)
         mddev->degraded += (raid_disks - conf->raid_disks);
         conf->raid_disks = mddev->raid_disks = raid_disks;
 
+        conf->last_used = 0; /* just make sure it is in-range */
         spin_lock_irq(&conf->resync_lock);
         conf->barrier--;
         spin_unlock_irq(&conf->resync_lock);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index e9dc2876a626..62ebb1bc72be 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -700,6 +700,8 @@ static int make_request(request_queue_t *q, struct bio * bio)
                 return 0;
         }
 
+        md_write_start(mddev, bio);
+
         /*
          * Register the new request and wait if the reconstruction
          * thread has put up a bar for new requests.
@@ -774,7 +776,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
         rcu_read_unlock();
 
         atomic_set(&r10_bio->remaining, 1);
-        md_write_start(mddev);
+
         for (i = 0; i < conf->copies; i++) {
                 struct bio *mbio;
                 int d = r10_bio->devs[i].devnum;
@@ -1216,7 +1218,6 @@ static void raid10d(mddev_t *mddev)
         mdk_rdev_t *rdev;
 
         md_check_recovery(mddev);
-        md_handle_safemode(mddev);
 
         for (;;) {
                 char b[BDEVNAME_SIZE];
@@ -1319,7 +1320,7 @@ static int init_resync(conf_t *conf)
  *
  */
 
-static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
+static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
 {
         conf_t *conf = mddev_to_conf(mddev);
         r10bio_t *r10_bio;
@@ -1333,7 +1334,7 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
 
         if (!conf->r10buf_pool)
                 if (init_resync(conf))
-                        return -ENOMEM;
+                        return 0;
 
  skipped:
         max_sector = mddev->size << 1;
@@ -1341,15 +1342,15 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
                 max_sector = mddev->resync_max_sectors;
         if (sector_nr >= max_sector) {
                 close_sync(conf);
+                *skipped = 1;
                 return sectors_skipped;
         }
         if (chunks_skipped >= conf->raid_disks) {
                 /* if there has been nothing to do on any drive,
                  * then there is nothing to do at all..
                  */
-                sector_t sec = max_sector - sector_nr;
-                md_done_sync(mddev, sec, 1);
-                return sec + sectors_skipped;
+                *skipped = 1;
+                return (max_sector - sector_nr) + sectors_skipped;
         }
 
         /* make sure whole request will fit in a chunk - if chunks
@@ -1563,17 +1564,22 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
                 }
         }
 
+        if (sectors_skipped)
+                /* pretend they weren't skipped, it makes
+                 * no important difference in this case
+                 */
+                md_done_sync(mddev, sectors_skipped, 1);
+
         return sectors_skipped + nr_sectors;
  giveup:
         /* There is nowhere to write, so all non-sync
          * drives must be failed, so try the next chunk...
          */
         {
-        int sec = max_sector - sector_nr;
+        sector_t sec = max_sector - sector_nr;
         sectors_skipped += sec;
         chunks_skipped ++;
         sector_nr = max_sector;
-        md_done_sync(mddev, sec, 1);
         goto skipped;
         }
 }
@@ -1639,9 +1645,6 @@ static int run(mddev_t *mddev)
                         mdname(mddev));
                 goto out_free_conf;
         }
-        mddev->queue->unplug_fn = raid10_unplug;
-
-        mddev->queue->issue_flush_fn = raid10_issue_flush;
 
         ITERATE_RDEV(mddev, rdev, tmp) {
                 disk_idx = rdev->raid_disk;
@@ -1713,6 +1716,9 @@ static int run(mddev_t *mddev)
         mddev->array_size = size/2;
         mddev->resync_max_sectors = size;
 
+        mddev->queue->unplug_fn = raid10_unplug;
+        mddev->queue->issue_flush_fn = raid10_issue_flush;
+
         /* Calculate max read-ahead size.
          * We need to readahead at least twice a whole stripe....
          * maybe...
@@ -1731,8 +1737,7 @@ static int run(mddev_t *mddev)
 out_free_conf:
         if (conf->r10bio_pool)
                 mempool_destroy(conf->r10bio_pool);
-        if (conf->mirrors)
-                kfree(conf->mirrors);
+        kfree(conf->mirrors);
         kfree(conf);
         mddev->private = NULL;
 out:
@@ -1748,8 +1753,7 @@ static int stop(mddev_t *mddev)
         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
         if (conf->r10bio_pool)
                 mempool_destroy(conf->r10bio_pool);
-        if (conf->mirrors)
-                kfree(conf->mirrors);
+        kfree(conf->mirrors);
         kfree(conf);
         mddev->private = NULL;
         return 0;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e96e2a10a9c9..93a9726cc2d6 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1411,6 +1411,8 @@ static int make_request (request_queue_t *q, struct bio * bi)
         sector_t logical_sector, last_sector;
         struct stripe_head *sh;
 
+        md_write_start(mddev, bi);
+
         if (bio_data_dir(bi)==WRITE) {
                 disk_stat_inc(mddev->gendisk, writes);
                 disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bi));
@@ -1423,8 +1425,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
         last_sector = bi->bi_sector + (bi->bi_size>>9);
         bi->bi_next = NULL;
         bi->bi_phys_segments = 1;       /* over-loaded to count active stripes */
-        if ( bio_data_dir(bi) == WRITE )
-                md_write_start(mddev);
+
         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
                 DEFINE_WAIT(w);
                 
@@ -1475,7 +1476,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
 }
 
 /* FIXME go_faster isn't used */
-static int sync_request (mddev_t *mddev, sector_t sector_nr, int go_faster)
+static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
 {
         raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
         struct stripe_head *sh;
@@ -1498,8 +1499,8 @@ static int sync_request (mddev_t *mddev, sector_t sector_nr, int go_faster)
          * nothing we can do.
          */
         if (mddev->degraded >= 1 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
-                int rv = (mddev->size << 1) - sector_nr;
-                md_done_sync(mddev, rv, 1);
+                sector_t rv = (mddev->size << 1) - sector_nr;
+                *skipped = 1;
                 return rv;
         }
 
@@ -1546,7 +1547,6 @@ static void raid5d (mddev_t *mddev)
         PRINTK("+++ raid5d active\n");
 
         md_check_recovery(mddev);
-        md_handle_safemode(mddev);
 
         handled = 0;
         spin_lock_irq(&conf->device_lock);
@@ -1620,9 +1620,6 @@ static int run (mddev_t *mddev)
         atomic_set(&conf->active_stripes, 0);
         atomic_set(&conf->preread_active_stripes, 0);
 
-        mddev->queue->unplug_fn = raid5_unplug_device;
-        mddev->queue->issue_flush_fn = raid5_issue_flush;
-
         PRINTK("raid5: run(%s) called.\n", mdname(mddev));
 
         ITERATE_RDEV(mddev,rdev,tmp) {
@@ -1728,6 +1725,10 @@ memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
         }
 
         /* Ok, everything is just fine now */
+
+        mddev->queue->unplug_fn = raid5_unplug_device;
+        mddev->queue->issue_flush_fn = raid5_issue_flush;
+
         mddev->array_size =  mddev->size * (mddev->raid_disks - 1);
         return 0;
 abort:
diff --git a/drivers/md/raid6main.c b/drivers/md/raid6main.c
index 8a33f351e092..f62ea1a73d0d 100644
--- a/drivers/md/raid6main.c
+++ b/drivers/md/raid6main.c
@@ -1570,6 +1570,8 @@ static int make_request (request_queue_t *q, struct bio * bi)
         sector_t logical_sector, last_sector;
         struct stripe_head *sh;
 
+        md_write_start(mddev, bi);
+
         if (bio_data_dir(bi)==WRITE) {
                 disk_stat_inc(mddev->gendisk, writes);
                 disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bi));
@@ -1583,8 +1585,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
 
         bi->bi_next = NULL;
         bi->bi_phys_segments = 1;       /* over-loaded to count active stripes */
-        if ( bio_data_dir(bi) == WRITE )
-                md_write_start(mddev);
+
         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
                 DEFINE_WAIT(w);
 
@@ -1634,7 +1635,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
 }
 
 /* FIXME go_faster isn't used */
-static int sync_request (mddev_t *mddev, sector_t sector_nr, int go_faster)
+static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
 {
         raid6_conf_t *conf = (raid6_conf_t *) mddev->private;
         struct stripe_head *sh;
@@ -1657,8 +1658,8 @@ static int sync_request (mddev_t *mddev, sector_t sector_nr, int go_faster)
          * nothing we can do.
          */
         if (mddev->degraded >= 2 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
-                int rv = (mddev->size << 1) - sector_nr;
-                md_done_sync(mddev, rv, 1);
+                sector_t rv = (mddev->size << 1) - sector_nr;
+                *skipped = 1;
                 return rv;
         }
 
@@ -1705,7 +1706,6 @@ static void raid6d (mddev_t *mddev)
         PRINTK("+++ raid6d active\n");
 
         md_check_recovery(mddev);
-        md_handle_safemode(mddev);
 
         handled = 0;
         spin_lock_irq(&conf->device_lock);
@@ -1779,9 +1779,6 @@ static int run (mddev_t *mddev)
         atomic_set(&conf->active_stripes, 0);
         atomic_set(&conf->preread_active_stripes, 0);
 
-        mddev->queue->unplug_fn = raid6_unplug_device;
-        mddev->queue->issue_flush_fn = raid6_issue_flush;
-
         PRINTK("raid6: run(%s) called.\n", mdname(mddev));
 
         ITERATE_RDEV(mddev,rdev,tmp) {
@@ -1895,6 +1892,9 @@ static int run (mddev_t *mddev)
 
         /* Ok, everything is just fine now */
         mddev->array_size =  mddev->size * (mddev->raid_disks - 2);
+
+        mddev->queue->unplug_fn = raid6_unplug_device;
+        mddev->queue->issue_flush_fn = raid6_issue_flush;
         return 0;
 abort:
         if (conf) {