md: support blocking writes to an array on device failure
[safe/jmp/linux-2.6] / drivers / md / raid10.c
index 3c37be6..5938fa9 100644 (file)
@@ -18,7 +18,9 @@
  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include "dm-bio-list.h"
 #include <linux/raid/raid10.h>
+#include <linux/raid/bitmap.h>
 
 /*
  * RAID10 provides a combination of RAID0 and RAID1 functionality.
@@ -27,6 +29,7 @@
  *    raid_disks
  *    near_copies (stored in low byte of layout)
  *    far_copies (stored in second byte of layout)
+ *    far_offset (stored in bit 16 of layout )
  *
  * The data to be stored is divided into chunks using chunksize.
  * Each device is divided into far_copies sections.
  * near_copies copies of each chunk is stored (each on a different drive).
  * The starting device for each section is offset near_copies from the starting
  * device of the previous section.
- * Thus there are (near_copies*far_copies) of each chunk, and each is on a different
+ * Thus they are (near_copies*far_copies) of each chunk, and each is on a different
  * drive.
  * near_copies and far_copies must be at least one, and their product is at most
  * raid_disks.
+ *
+ * If far_offset is true, then the far_copies are handled a bit differently.
+ * The copies are still in different stripes, but instead of be very far apart
+ * on disk, there are adjacent stripes.
  */
 
 /*
 
 static void unplug_slaves(mddev_t *mddev);
 
-static void * r10bio_pool_alloc(unsigned int __nocast gfp_flags, void *data)
+static void allow_barrier(conf_t *conf);
+static void lower_barrier(conf_t *conf);
+
+static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
 {
        conf_t *conf = data;
        r10bio_t *r10_bio;
        int size = offsetof(struct r10bio_s, devs[conf->copies]);
 
        /* allocate a r10bio with room for raid_disks entries in the bios array */
-       r10_bio = kmalloc(size, gfp_flags);
-       if (r10_bio)
-               memset(r10_bio, 0, size);
-       else
+       r10_bio = kzalloc(size, gfp_flags);
+       if (!r10_bio)
                unplug_slaves(conf->mddev);
 
        return r10_bio;
@@ -81,7 +89,7 @@ static void r10bio_pool_free(void *r10_bio, void *data)
  * one for write (we recover only one drive per r10buf)
  *
  */
-static void * r10buf_pool_alloc(unsigned int __nocast gfp_flags, void *data)
+static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
 {
        conf_t *conf = data;
        struct page *page;
@@ -129,10 +137,10 @@ static void * r10buf_pool_alloc(unsigned int __nocast gfp_flags, void *data)
 
 out_free_pages:
        for ( ; i > 0 ; i--)
-               __free_page(bio->bi_io_vec[i-1].bv_page);
+               safe_put_page(bio->bi_io_vec[i-1].bv_page);
        while (j--)
                for (i = 0; i < RESYNC_PAGES ; i++)
-                       __free_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
+                       safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
        j = -1;
 out_free_bio:
        while ( ++j < nalloc )
@@ -152,7 +160,7 @@ static void r10buf_pool_free(void *__r10_bio, void *data)
                struct bio *bio = r10bio->devs[j].bio;
                if (bio) {
                        for (i = 0; i < RESYNC_PAGES; i++) {
-                               __free_page(bio->bi_io_vec[i].bv_page);
+                               safe_put_page(bio->bi_io_vec[i].bv_page);
                                bio->bi_io_vec[i].bv_page = NULL;
                        }
                        bio_put(bio);
@@ -167,52 +175,33 @@ static void put_all_bios(conf_t *conf, r10bio_t *r10_bio)
 
        for (i = 0; i < conf->copies; i++) {
                struct bio **bio = & r10_bio->devs[i].bio;
-               if (*bio)
+               if (*bio && *bio != IO_BLOCKED)
                        bio_put(*bio);
                *bio = NULL;
        }
 }
 
-static inline void free_r10bio(r10bio_t *r10_bio)
+static void free_r10bio(r10bio_t *r10_bio)
 {
-       unsigned long flags;
-
        conf_t *conf = mddev_to_conf(r10_bio->mddev);
 
        /*
         * Wake up any possible resync thread that waits for the device
         * to go idle.
         */
-       spin_lock_irqsave(&conf->resync_lock, flags);
-       if (!--conf->nr_pending) {
-               wake_up(&conf->wait_idle);
-               wake_up(&conf->wait_resume);
-       }
-       spin_unlock_irqrestore(&conf->resync_lock, flags);
+       allow_barrier(conf);
 
        put_all_bios(conf, r10_bio);
        mempool_free(r10_bio, conf->r10bio_pool);
 }
 
-static inline void put_buf(r10bio_t *r10_bio)
+static void put_buf(r10bio_t *r10_bio)
 {
        conf_t *conf = mddev_to_conf(r10_bio->mddev);
-       unsigned long flags;
 
        mempool_free(r10_bio, conf->r10buf_pool);
 
-       spin_lock_irqsave(&conf->resync_lock, flags);
-       if (!conf->barrier)
-               BUG();
-       --conf->barrier;
-       wake_up(&conf->wait_resume);
-       wake_up(&conf->wait_idle);
-
-       if (!--conf->nr_pending) {
-               wake_up(&conf->wait_idle);
-               wake_up(&conf->wait_resume);
-       }
-       spin_unlock_irqrestore(&conf->resync_lock, flags);
+       lower_barrier(conf);
 }
 
 static void reschedule_retry(r10bio_t *r10_bio)
@@ -223,6 +212,7 @@ static void reschedule_retry(r10bio_t *r10_bio)
 
        spin_lock_irqsave(&conf->device_lock, flags);
        list_add(&r10_bio->retry_list, &conf->retry_list);
+       conf->nr_queued ++;
        spin_unlock_irqrestore(&conf->device_lock, flags);
 
        md_wakeup_thread(mddev->thread);
@@ -237,7 +227,7 @@ static void raid_end_bio_io(r10bio_t *r10_bio)
 {
        struct bio *bio = r10_bio->master_bio;
 
-       bio_endio(bio, bio->bi_size,
+       bio_endio(bio,
                test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO);
        free_r10bio(r10_bio);
 }
@@ -253,24 +243,22 @@ static inline void update_head_pos(int slot, r10bio_t *r10_bio)
                r10_bio->devs[slot].addr + (r10_bio->sectors);
 }
 
-static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
+static void raid10_end_read_request(struct bio *bio, int error)
 {
        int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
        r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
        int slot, dev;
        conf_t *conf = mddev_to_conf(r10_bio->mddev);
 
-       if (bio->bi_size)
-               return 1;
 
        slot = r10_bio->read_slot;
        dev = r10_bio->devs[slot].devnum;
        /*
         * this branch is our 'one mirror IO has finished' event handler:
         */
-       if (!uptodate)
-               md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
-       else
+       update_head_pos(slot, r10_bio);
+
+       if (uptodate) {
                /*
                 * Set R10BIO_Uptodate in our master bio, so that
                 * we will return a good error code to the higher
@@ -281,15 +269,8 @@ static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int
                 * wait for the 'master' bio.
                 */
                set_bit(R10BIO_Uptodate, &r10_bio->state);
-
-       update_head_pos(slot, r10_bio);
-
-       /*
-        * we have only one bio on the read side
-        */
-       if (uptodate)
                raid_end_bio_io(r10_bio);
-       else {
+       else {
                /*
                 * oops, read error:
                 */
@@ -301,19 +282,15 @@ static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int
        }
 
        rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
-       return 0;
 }
 
-static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
+static void raid10_end_write_request(struct bio *bio, int error)
 {
        int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
        r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
        int slot, dev;
        conf_t *conf = mddev_to_conf(r10_bio->mddev);
 
-       if (bio->bi_size)
-               return 1;
-
        for (slot = 0; slot < conf->copies; slot++)
                if (r10_bio->devs[slot].bio == bio)
                        break;
@@ -322,9 +299,11 @@ static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, in
        /*
         * this branch is our 'one mirror IO has finished' event handler:
         */
-       if (!uptodate)
+       if (!uptodate) {
                md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
-       else
+               /* an I/O failed, we can't clear the bitmap */
+               set_bit(R10BIO_Degraded, &r10_bio->state);
+       } else
                /*
                 * Set R10BIO_Uptodate in our master bio, so that
                 * we will return a good error code for to the higher
@@ -344,12 +323,16 @@ static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, in
         * already.
         */
        if (atomic_dec_and_test(&r10_bio->remaining)) {
+               /* clear the bitmap if all writes complete successfully */
+               bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
+                               r10_bio->sectors,
+                               !test_bit(R10BIO_Degraded, &r10_bio->state),
+                               0);
                md_write_end(r10_bio->mddev);
                raid_end_bio_io(r10_bio);
        }
 
        rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
-       return 0;
 }
 
 
@@ -372,8 +355,7 @@ static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, in
  * With this layout, and block is never stored twice on the one device.
  *
  * raid10_find_phys finds the sector offset of a given virtual sector
- * on each device that it is on. If a block isn't on a device,
- * that entry in the array is set to MaxSector.
+ * on each device that it is on.
  *
  * raid10_find_virt does the reverse mapping, from a device and a
  * sector offset to a virtual address
@@ -396,6 +378,8 @@ static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio)
        chunk *= conf->near_copies;
        stripe = chunk;
        dev = sector_div(stripe, conf->raid_disks);
+       if (conf->far_offset)
+               stripe *= conf->far_copies;
 
        sector += stripe << conf->chunk_shift;
 
@@ -429,16 +413,24 @@ static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev)
 {
        sector_t offset, chunk, vchunk;
 
-       while (sector > conf->stride) {
-               sector -= conf->stride;
-               if (dev < conf->near_copies)
-                       dev += conf->raid_disks - conf->near_copies;
-               else
-                       dev -= conf->near_copies;
-       }
-
        offset = sector & conf->chunk_mask;
-       chunk = sector >> conf->chunk_shift;
+       if (conf->far_offset) {
+               int fc;
+               chunk = sector >> conf->chunk_shift;
+               fc = sector_div(chunk, conf->far_copies);
+               dev -= fc * conf->near_copies;
+               if (dev < 0)
+                       dev += conf->raid_disks;
+       } else {
+               while (sector >= conf->stride) {
+                       sector -= conf->stride;
+                       if (dev < conf->near_copies)
+                               dev += conf->raid_disks - conf->near_copies;
+                       else
+                               dev -= conf->near_copies;
+               }
+               chunk = sector >> conf->chunk_shift;
+       }
        vchunk = chunk * conf->raid_disks + dev;
        sector_div(vchunk, conf->near_copies);
        return (vchunk << conf->chunk_shift) + offset;
@@ -454,7 +446,7 @@ static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev)
  *      If near_copies == raid_disk, there are no striping issues,
  *      but in that case, the function isn't called at all.
  */
-static int raid10_mergeable_bvec(request_queue_t *q, struct bio *bio,
+static int raid10_mergeable_bvec(struct request_queue *q, struct bio *bio,
                                struct bio_vec *bio_vec)
 {
        mddev_t *mddev = q->queuedata;
@@ -496,13 +488,15 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
        int disk, slot, nslot;
        const int sectors = r10_bio->sectors;
        sector_t new_distance, current_distance;
+       mdk_rdev_t *rdev;
 
        raid10_find_phys(conf, r10_bio);
        rcu_read_lock();
        /*
         * Check if we can balance. We can balance on the whole
-        * device if no resync is going on, or below the resync window.
-        * We take the first readable disk when above the resync window.
+        * device if no resync is going on (recovery is ok), or below
+        * the resync window. We take the first readable disk when
+        * above the resync window.
         */
        if (conf->mddev->recovery_cp < MaxSector
            && (this_sector + sectors >= conf->next_resync)) {
@@ -510,8 +504,9 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
                slot = 0;
                disk = r10_bio->devs[slot].devnum;
 
-               while (!conf->mirrors[disk].rdev ||
-                      !conf->mirrors[disk].rdev->in_sync) {
+               while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
+                      r10_bio->devs[slot].bio == IO_BLOCKED ||
+                      !test_bit(In_sync, &rdev->flags)) {
                        slot++;
                        if (slot == conf->copies) {
                                slot = 0;
@@ -527,8 +522,9 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
        /* make sure the disk is operational */
        slot = 0;
        disk = r10_bio->devs[slot].devnum;
-       while (!conf->mirrors[disk].rdev ||
-              !conf->mirrors[disk].rdev->in_sync) {
+       while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
+              r10_bio->devs[slot].bio == IO_BLOCKED ||
+              !test_bit(In_sync, &rdev->flags)) {
                slot ++;
                if (slot == conf->copies) {
                        disk = -1;
@@ -538,25 +534,37 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
        }
 
 
-       current_distance = abs(this_sector - conf->mirrors[disk].head_position);
+       current_distance = abs(r10_bio->devs[slot].addr -
+                              conf->mirrors[disk].head_position);
 
-       /* Find the disk whose head is closest */
+       /* Find the disk whose head is closest,
+        * or - for far > 1 - find the closest to partition beginning */
 
        for (nslot = slot; nslot < conf->copies; nslot++) {
                int ndisk = r10_bio->devs[nslot].devnum;
 
 
-               if (!conf->mirrors[ndisk].rdev ||
-                   !conf->mirrors[ndisk].rdev->in_sync)
+               if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL ||
+                   r10_bio->devs[nslot].bio == IO_BLOCKED ||
+                   !test_bit(In_sync, &rdev->flags))
                        continue;
 
-               if (!atomic_read(&conf->mirrors[ndisk].rdev->nr_pending)) {
+               /* This optimisation is debatable, and completely destroys
+                * sequential read speed for 'far copies' arrays.  So only
+                * keep it for 'near' arrays, and review those later.
+                */
+               if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending)) {
                        disk = ndisk;
                        slot = nslot;
                        break;
                }
-               new_distance = abs(r10_bio->devs[nslot].addr -
-                                  conf->mirrors[ndisk].head_position);
+
+               /* for far > 1 always use the lowest address */
+               if (conf->far_copies > 1)
+                       new_distance = r10_bio->devs[nslot].addr;
+               else
+                       new_distance = abs(r10_bio->devs[nslot].addr -
+                                          conf->mirrors[ndisk].head_position);
                if (new_distance < current_distance) {
                        current_distance = new_distance;
                        disk = ndisk;
@@ -568,8 +576,10 @@ rb_out:
        r10_bio->read_slot = slot;
 /*     conf->next_seq_sect = this_sector + sectors;*/
 
-       if (disk >= 0 && conf->mirrors[disk].rdev)
+       if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL)
                atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
+       else
+               disk = -1;
        rcu_read_unlock();
 
        return disk;
@@ -582,15 +592,14 @@ static void unplug_slaves(mddev_t *mddev)
 
        rcu_read_lock();
        for (i=0; i<mddev->raid_disks; i++) {
-               mdk_rdev_t *rdev = conf->mirrors[i].rdev;
-               if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
-                       request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
+               mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
+               if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
+                       struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
 
                        atomic_inc(&rdev->nr_pending);
                        rcu_read_unlock();
 
-                       if (r_queue->unplug_fn)
-                               r_queue->unplug_fn(r_queue);
+                       blk_unplug(r_queue);
 
                        rdev_dec_pending(rdev, mddev);
                        rcu_read_lock();
@@ -599,66 +608,176 @@ static void unplug_slaves(mddev_t *mddev)
        rcu_read_unlock();
 }
 
-static void raid10_unplug(request_queue_t *q)
+static void raid10_unplug(struct request_queue *q)
 {
+       mddev_t *mddev = q->queuedata;
+
        unplug_slaves(q->queuedata);
+       md_wakeup_thread(mddev->thread);
 }
 
-static int raid10_issue_flush(request_queue_t *q, struct gendisk *disk,
-                            sector_t *error_sector)
+static int raid10_congested(void *data, int bits)
 {
-       mddev_t *mddev = q->queuedata;
+       mddev_t *mddev = data;
        conf_t *conf = mddev_to_conf(mddev);
        int i, ret = 0;
 
        rcu_read_lock();
-       for (i=0; i<mddev->raid_disks && ret == 0; i++) {
-               mdk_rdev_t *rdev = conf->mirrors[i].rdev;
-               if (rdev && !rdev->faulty) {
-                       struct block_device *bdev = rdev->bdev;
-                       request_queue_t *r_queue = bdev_get_queue(bdev);
-
-                       if (!r_queue->issue_flush_fn)
-                               ret = -EOPNOTSUPP;
-                       else {
-                               atomic_inc(&rdev->nr_pending);
-                               rcu_read_unlock();
-                               ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
-                                                             error_sector);
-                               rdev_dec_pending(rdev, mddev);
-                               rcu_read_lock();
-                       }
+       for (i = 0; i < mddev->raid_disks && ret == 0; i++) {
+               mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
+               if (rdev && !test_bit(Faulty, &rdev->flags)) {
+                       struct request_queue *q = bdev_get_queue(rdev->bdev);
+
+                       ret |= bdi_congested(&q->backing_dev_info, bits);
                }
        }
        rcu_read_unlock();
        return ret;
 }
 
-/*
- * Throttle resync depth, so that we can both get proper overlapping of
- * requests, but are still able to handle normal requests quickly.
+static int flush_pending_writes(conf_t *conf)
+{
+       /* Any writes that have been queued but are awaiting
+        * bitmap updates get flushed here.
+        * We return 1 if any requests were actually submitted.
+        */
+       int rv = 0;
+
+       spin_lock_irq(&conf->device_lock);
+
+       if (conf->pending_bio_list.head) {
+               struct bio *bio;
+               bio = bio_list_get(&conf->pending_bio_list);
+               blk_remove_plug(conf->mddev->queue);
+               spin_unlock_irq(&conf->device_lock);
+               /* flush any pending bitmap writes to disk
+                * before proceeding w/ I/O */
+               bitmap_unplug(conf->mddev->bitmap);
+
+               while (bio) { /* submit pending writes */
+                       struct bio *next = bio->bi_next;
+                       bio->bi_next = NULL;
+                       generic_make_request(bio);
+                       bio = next;
+               }
+               rv = 1;
+       } else
+               spin_unlock_irq(&conf->device_lock);
+       return rv;
+}
+/* Barriers....
+ * Sometimes we need to suspend IO while we do something else,
+ * either some resync/recovery, or reconfigure the array.
+ * To do this we raise a 'barrier'.
+ * The 'barrier' is a counter that can be raised multiple times
+ * to count how many activities are happening which preclude
+ * normal IO.
+ * We can only raise the barrier if there is no pending IO.
+ * i.e. if nr_pending == 0.
+ * We choose only to raise the barrier if no-one is waiting for the
+ * barrier to go down.  This means that as soon as an IO request
+ * is ready, no other operations which require a barrier will start
+ * until the IO request has had a chance.
+ *
+ * So: regular IO calls 'wait_barrier'.  When that returns there
+ *    is no backgroup IO happening,  It must arrange to call
+ *    allow_barrier when it has finished its IO.
+ * backgroup IO calls must call raise_barrier.  Once that returns
+ *    there is no normal IO happeing.  It must arrange to call
+ *    lower_barrier when the particular background IO completes.
  */
 #define RESYNC_DEPTH 32
 
-static void device_barrier(conf_t *conf, sector_t sect)
+static void raise_barrier(conf_t *conf, int force)
 {
+       BUG_ON(force && !conf->barrier);
        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));
-
-       if (!conf->barrier++) {
-               wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
-                                   conf->resync_lock, unplug_slaves(conf->mddev));
-               if (conf->nr_pending)
-                       BUG();
+
+       /* Wait until no block IO is waiting (unless 'force') */
+       wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
+                           conf->resync_lock,
+                           raid10_unplug(conf->mddev->queue));
+
+       /* block any new IO from starting */
+       conf->barrier++;
+
+       /* No wait for all pending IO to complete */
+       wait_event_lock_irq(conf->wait_barrier,
+                           !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
+                           conf->resync_lock,
+                           raid10_unplug(conf->mddev->queue));
+
+       spin_unlock_irq(&conf->resync_lock);
+}
+
+static void lower_barrier(conf_t *conf)
+{
+       unsigned long flags;
+       spin_lock_irqsave(&conf->resync_lock, flags);
+       conf->barrier--;
+       spin_unlock_irqrestore(&conf->resync_lock, flags);
+       wake_up(&conf->wait_barrier);
+}
+
+static void wait_barrier(conf_t *conf)
+{
+       spin_lock_irq(&conf->resync_lock);
+       if (conf->barrier) {
+               conf->nr_waiting++;
+               wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
+                                   conf->resync_lock,
+                                   raid10_unplug(conf->mddev->queue));
+               conf->nr_waiting--;
        }
-       wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH,
-                           conf->resync_lock, unplug_slaves(conf->mddev));
-       conf->next_resync = sect;
+       conf->nr_pending++;
+       spin_unlock_irq(&conf->resync_lock);
+}
+
+static void allow_barrier(conf_t *conf)
+{
+       unsigned long flags;
+       spin_lock_irqsave(&conf->resync_lock, flags);
+       conf->nr_pending--;
+       spin_unlock_irqrestore(&conf->resync_lock, flags);
+       wake_up(&conf->wait_barrier);
+}
+
+static void freeze_array(conf_t *conf)
+{
+       /* stop syncio and normal IO and wait for everything to
+        * go quiet.
+        * We increment barrier and nr_waiting, and then
+        * wait until nr_pending match nr_queued+1
+        * This is called in the context of one normal IO request
+        * that has failed. Thus any sync request that might be pending
+        * will be blocked by nr_pending, and we need to wait for
+        * pending IO requests to complete or be queued for re-try.
+        * Thus the number queued (nr_queued) plus this request (1)
+        * must match the number of pending IOs (nr_pending) before
+        * we continue.
+        */
+       spin_lock_irq(&conf->resync_lock);
+       conf->barrier++;
+       conf->nr_waiting++;
+       wait_event_lock_irq(conf->wait_barrier,
+                           conf->nr_pending == conf->nr_queued+1,
+                           conf->resync_lock,
+                           ({ flush_pending_writes(conf);
+                              raid10_unplug(conf->mddev->queue); }));
+       spin_unlock_irq(&conf->resync_lock);
+}
+
+static void unfreeze_array(conf_t *conf)
+{
+       /* reverse the effect of the freeze */
+       spin_lock_irq(&conf->resync_lock);
+       conf->barrier--;
+       conf->nr_waiting--;
+       wake_up(&conf->wait_barrier);
        spin_unlock_irq(&conf->resync_lock);
 }
 
-static int make_request(request_queue_t *q, struct bio * bio)
+static int make_request(struct request_queue *q, struct bio * bio)
 {
        mddev_t *mddev = q->queuedata;
        conf_t *conf = mddev_to_conf(mddev);
@@ -667,6 +786,16 @@ static int make_request(request_queue_t *q, struct bio * bio)
        struct bio *read_bio;
        int i;
        int chunk_sects = conf->chunk_mask + 1;
+       const int rw = bio_data_dir(bio);
+       const int do_sync = bio_sync(bio);
+       struct bio_list bl;
+       unsigned long flags;
+       mdk_rdev_t *blocked_rdev;
+
+       if (unlikely(bio_barrier(bio))) {
+               bio_endio(bio, -EOPNOTSUPP);
+               return 0;
+       }
 
        /* If this request crosses a chunk boundary, we need to
         * split it.  This will only happen for 1 PAGE (or less) requests.
@@ -696,27 +825,21 @@ static int make_request(request_queue_t *q, struct bio * bio)
                       " or bigger than %dk %llu %d\n", chunk_sects/2,
                       (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
 
-               bio_io_error(bio, bio->bi_size);
+               bio_io_error(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.
         * Continue immediately if no resync is active currently.
         */
-       spin_lock_irq(&conf->resync_lock);
-       wait_event_lock_irq(conf->wait_resume, !conf->barrier, conf->resync_lock, );
-       conf->nr_pending++;
-       spin_unlock_irq(&conf->resync_lock);
+       wait_barrier(conf);
 
-       if (bio_data_dir(bio)==WRITE) {
-               disk_stat_inc(mddev->gendisk, writes);
-               disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
-       } else {
-               disk_stat_inc(mddev->gendisk, reads);
-               disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
-       }
+       disk_stat_inc(mddev->gendisk, ios[rw]);
+       disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
 
        r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
 
@@ -725,8 +848,9 @@ static int make_request(request_queue_t *q, struct bio * bio)
 
        r10_bio->mddev = mddev;
        r10_bio->sector = bio->bi_sector;
+       r10_bio->state = 0;
 
-       if (bio_data_dir(bio) == READ) {
+       if (rw == READ) {
                /*
                 * read balancing logic:
                 */
@@ -746,7 +870,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
                        mirror->rdev->data_offset;
                read_bio->bi_bdev = mirror->rdev->bdev;
                read_bio->bi_end_io = raid10_end_read_request;
-               read_bio->bi_rw = READ;
+               read_bio->bi_rw = READ | do_sync;
                read_bio->bi_private = r10_bio;
 
                generic_make_request(read_bio);
@@ -756,25 +880,51 @@ static int make_request(request_queue_t *q, struct bio * bio)
        /*
         * WRITE:
         */
-       /* first select target devices under spinlock and
+       /* first select target devices under rcu_lock and
         * inc refcount on their rdev.  Record them by setting
         * bios[x] to bio
         */
        raid10_find_phys(conf, r10_bio);
+ retry_write:
+       blocked_rdev = 0;
        rcu_read_lock();
        for (i = 0;  i < conf->copies; i++) {
                int d = r10_bio->devs[i].devnum;
-               if (conf->mirrors[d].rdev &&
-                   !conf->mirrors[d].rdev->faulty) {
-                       atomic_inc(&conf->mirrors[d].rdev->nr_pending);
+               mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev);
+               if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
+                       atomic_inc(&rdev->nr_pending);
+                       blocked_rdev = rdev;
+                       break;
+               }
+               if (rdev && !test_bit(Faulty, &rdev->flags)) {
+                       atomic_inc(&rdev->nr_pending);
                        r10_bio->devs[i].bio = bio;
-               } else
+               } else {
                        r10_bio->devs[i].bio = NULL;
+                       set_bit(R10BIO_Degraded, &r10_bio->state);
+               }
        }
        rcu_read_unlock();
 
-       atomic_set(&r10_bio->remaining, 1);
-       md_write_start(mddev);
+       if (unlikely(blocked_rdev)) {
+               /* Have to wait for this device to get unblocked, then retry */
+               int j;
+               int d;
+
+               for (j = 0; j < i; j++)
+                       if (r10_bio->devs[j].bio) {
+                               d = r10_bio->devs[j].devnum;
+                               rdev_dec_pending(conf->mirrors[d].rdev, mddev);
+                       }
+               allow_barrier(conf);
+               md_wait_for_blocked_rdev(blocked_rdev, mddev);
+               wait_barrier(conf);
+               goto retry_write;
+       }
+
+       atomic_set(&r10_bio->remaining, 0);
+
+       bio_list_init(&bl);
        for (i = 0; i < conf->copies; i++) {
                struct bio *mbio;
                int d = r10_bio->devs[i].devnum;
@@ -788,18 +938,32 @@ static int make_request(request_queue_t *q, struct bio * bio)
                        conf->mirrors[d].rdev->data_offset;
                mbio->bi_bdev = conf->mirrors[d].rdev->bdev;
                mbio->bi_end_io = raid10_end_write_request;
-               mbio->bi_rw = WRITE;
+               mbio->bi_rw = WRITE | do_sync;
                mbio->bi_private = r10_bio;
 
                atomic_inc(&r10_bio->remaining);
-               generic_make_request(mbio);
+               bio_list_add(&bl, mbio);
        }
 
-       if (atomic_dec_and_test(&r10_bio->remaining)) {
+       if (unlikely(!atomic_read(&r10_bio->remaining))) {
+               /* the array is dead */
                md_write_end(mddev);
                raid_end_bio_io(r10_bio);
+               return 0;
        }
 
+       bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0);
+       spin_lock_irqsave(&conf->device_lock, flags);
+       bio_list_merge(&conf->pending_bio_list, &bl);
+       blk_plug_device(mddev->queue);
+       spin_unlock_irqrestore(&conf->device_lock, flags);
+
+       /* In case raid10d snuck in to freeze_array */
+       wake_up(&conf->wait_barrier);
+
+       if (do_sync)
+               md_wakeup_thread(mddev->thread);
+
        return 0;
 }
 
@@ -812,15 +976,18 @@ static void status(struct seq_file *seq, mddev_t *mddev)
                seq_printf(seq, " %dK chunks", mddev->chunk_size/1024);
        if (conf->near_copies > 1)
                seq_printf(seq, " %d near-copies", conf->near_copies);
-       if (conf->far_copies > 1)
-               seq_printf(seq, " %d far-copies", conf->far_copies);
-
+       if (conf->far_copies > 1) {
+               if (conf->far_offset)
+                       seq_printf(seq, " %d offset-copies", conf->far_copies);
+               else
+                       seq_printf(seq, " %d far-copies", conf->far_copies);
+       }
        seq_printf(seq, " [%d/%d] [", conf->raid_disks,
-                                               conf->working_disks);
+                                       conf->raid_disks - mddev->degraded);
        for (i = 0; i < conf->raid_disks; i++)
                seq_printf(seq, "%s",
                              conf->mirrors[i].rdev &&
-                             conf->mirrors[i].rdev->in_sync ? "U" : "_");
+                             test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
        seq_printf(seq, "]");
 }
 
@@ -835,8 +1002,8 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev)
         * next level up know.
         * else mark the drive as failed
         */
-       if (rdev->in_sync
-           && conf->working_disks == 1)
+       if (test_bit(In_sync, &rdev->flags)
+           && conf->raid_disks-mddev->degraded == 1)
                /*
                 * Don't fail the drive, just return an IO error.
                 * The test should really be more sophisticated than
@@ -845,20 +1012,21 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev)
                 * really dead" tests...
                 */
                return;
-       if (rdev->in_sync) {
+       if (test_and_clear_bit(In_sync, &rdev->flags)) {
+               unsigned long flags;
+               spin_lock_irqsave(&conf->device_lock, flags);
                mddev->degraded++;
-               conf->working_disks--;
+               spin_unlock_irqrestore(&conf->device_lock, flags);
                /*
                 * if recovery is running, make sure it aborts.
                 */
                set_bit(MD_RECOVERY_ERR, &mddev->recovery);
        }
-       rdev->in_sync = 0;
-       rdev->faulty = 1;
-       mddev->sb_dirty = 1;
-       printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n"
-               "       Operation continuing on %d devices\n",
-               bdevname(rdev->bdev,b), conf->working_disks);
+       set_bit(Faulty, &rdev->flags);
+       set_bit(MD_CHANGE_DEVS, &mddev->flags);
+       printk(KERN_ALERT "raid10: Disk failure on %s, disabling device.\n"
+               "raid10: Operation continuing on %d devices.\n",
+               bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
 }
 
 static void print_conf(conf_t *conf)
@@ -871,7 +1039,7 @@ static void print_conf(conf_t *conf)
                printk("(!conf)\n");
                return;
        }
-       printk(" --- wd:%d rd:%d\n", conf->working_disks,
+       printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
                conf->raid_disks);
 
        for (i = 0; i < conf->raid_disks; i++) {
@@ -879,25 +1047,42 @@ static void print_conf(conf_t *conf)
                tmp = conf->mirrors + i;
                if (tmp->rdev)
                        printk(" disk %d, wo:%d, o:%d, dev:%s\n",
-                               i, !tmp->rdev->in_sync, !tmp->rdev->faulty,
+                               i, !test_bit(In_sync, &tmp->rdev->flags),
+                               !test_bit(Faulty, &tmp->rdev->flags),
                                bdevname(tmp->rdev->bdev,b));
        }
 }
 
 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));
-       spin_unlock_irq(&conf->resync_lock);
-
-       if (conf->barrier) BUG();
-       if (waitqueue_active(&conf->wait_idle)) BUG();
+       wait_barrier(conf);
+       allow_barrier(conf);
 
        mempool_destroy(conf->r10buf_pool);
        conf->r10buf_pool = NULL;
 }
 
+/* check if there are enough drives for
+ * every block to appear on atleast one
+ */
+static int enough(conf_t *conf)
+{
+       int first = 0;
+
+       do {
+               int n = conf->copies;
+               int cnt = 0;
+               while (n--) {
+                       if (conf->mirrors[first].rdev)
+                               cnt++;
+                       first = (first+1) % conf->raid_disks;
+               }
+               if (cnt == 0)
+                       return 0;
+       } while (first != 0);
+       return 1;
+}
+
 static int raid10_spare_active(mddev_t *mddev)
 {
        int i;
@@ -911,11 +1096,12 @@ static int raid10_spare_active(mddev_t *mddev)
        for (i = 0; i < conf->raid_disks; i++) {
                tmp = conf->mirrors + i;
                if (tmp->rdev
-                   && !tmp->rdev->faulty
-                   && !tmp->rdev->in_sync) {
-                       conf->working_disks++;
+                   && !test_bit(Faulty, &tmp->rdev->flags)
+                   && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
+                       unsigned long flags;
+                       spin_lock_irqsave(&conf->device_lock, flags);
                        mddev->degraded--;
-                       tmp->rdev->in_sync = 1;
+                       spin_unlock_irqrestore(&conf->device_lock, flags);
                }
        }
 
@@ -936,8 +1122,15 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                 * very different from resync
                 */
                return 0;
+       if (!enough(conf))
+               return 0;
 
-       for (mirror=0; mirror < mddev->raid_disks; mirror++)
+       if (rdev->saved_raid_disk >= 0 &&
+           conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
+               mirror = rdev->saved_raid_disk;
+       else
+               mirror = 0;
+       for ( ; mirror < mddev->raid_disks; mirror++)
                if ( !(p=conf->mirrors+mirror)->rdev) {
 
                        blk_queue_stack_limits(mddev->queue,
@@ -953,7 +1146,9 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                        p->head_position = 0;
                        rdev->raid_disk = mirror;
                        found = 1;
-                       p->rdev = rdev;
+                       if (rdev->saved_raid_disk != mirror)
+                               conf->fullsync = 1;
+                       rcu_assign_pointer(p->rdev, rdev);
                        break;
                }
 
@@ -971,7 +1166,7 @@ static int raid10_remove_disk(mddev_t *mddev, int number)
        print_conf(conf);
        rdev = p->rdev;
        if (rdev) {
-               if (rdev->in_sync ||
+               if (test_bit(In_sync, &rdev->flags) ||
                    atomic_read(&rdev->nr_pending)) {
                        err = -EBUSY;
                        goto abort;
@@ -991,26 +1186,28 @@ abort:
 }
 
 
-static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
+static void end_sync_read(struct bio *bio, int error)
 {
-       int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
        r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
        conf_t *conf = mddev_to_conf(r10_bio->mddev);
        int i,d;
 
-       if (bio->bi_size)
-               return 1;
-
        for (i=0; i<conf->copies; i++)
                if (r10_bio->devs[i].bio == bio)
                        break;
-       if (i == conf->copies)
-               BUG();
+       BUG_ON(i == conf->copies);
        update_head_pos(i, r10_bio);
        d = r10_bio->devs[i].devnum;
-       if (!uptodate)
-               md_error(r10_bio->mddev,
-                        conf->mirrors[d].rdev);
+
+       if (test_bit(BIO_UPTODATE, &bio->bi_flags))
+               set_bit(R10BIO_Uptodate, &r10_bio->state);
+       else {
+               atomic_add(r10_bio->sectors,
+                          &conf->mirrors[d].rdev->corrected_errors);
+               if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
+                       md_error(r10_bio->mddev,
+                                conf->mirrors[d].rdev);
+       }
 
        /* for reconstruct, we always reschedule after a read.
         * for resync, only after all reads
@@ -1023,10 +1220,9 @@ static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
                reschedule_retry(r10_bio);
        }
        rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
-       return 0;
 }
 
-static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
+static void end_sync_write(struct bio *bio, int error)
 {
        int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
        r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
@@ -1034,9 +1230,6 @@ static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
        conf_t *conf = mddev_to_conf(mddev);
        int i,d;
 
-       if (bio->bi_size)
-               return 1;
-
        for (i = 0; i < conf->copies; i++)
                if (r10_bio->devs[i].bio == bio)
                        break;
@@ -1059,7 +1252,6 @@ static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
                }
        }
        rdev_dec_pending(conf->mirrors[d].rdev, mddev);
-       return 0;
 }
 
 /*
@@ -1098,23 +1290,32 @@ static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio)
        fbio = r10_bio->devs[i].bio;
 
        /* now find blocks with errors */
-       for (i=first+1 ; i < conf->copies ; i++) {
-               int vcnt, j, d;
+       for (i=0 ; i < conf->copies ; i++) {
+               int  j, d;
+               int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
 
-               if (!test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
-                       continue;
-               /* We know that the bi_io_vec layout is the same for
-                * both 'first' and 'i', so we just compare them.
-                * All vec entries are PAGE_SIZE;
-                */
                tbio = r10_bio->devs[i].bio;
-               vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
-               for (j = 0; j < vcnt; j++)
-                       if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
-                                  page_address(tbio->bi_io_vec[j].bv_page),
-                                  PAGE_SIZE))
-                               break;
-               if (j == vcnt)
+
+               if (tbio->bi_end_io != end_sync_read)
+                       continue;
+               if (i == first)
+                       continue;
+               if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) {
+                       /* We know that the bi_io_vec layout is the same for
+                        * both 'first' and 'i', so we just compare them.
+                        * All vec entries are PAGE_SIZE;
+                        */
+                       for (j = 0; j < vcnt; j++)
+                               if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
+                                          page_address(tbio->bi_io_vec[j].bv_page),
+                                          PAGE_SIZE))
+                                       break;
+                       if (j == vcnt)
+                               continue;
+                       mddev->resync_mismatches += r10_bio->sectors;
+               }
+               if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
+                       /* Don't fix anything. */
                        continue;
                /* Ok, we need to write this bio
                 * First we need to fixup bv_offset, bv_len and
@@ -1193,7 +1394,10 @@ static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
 
        atomic_inc(&conf->mirrors[d].rdev->nr_pending);
        md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
-       generic_make_request(wbio);
+       if (test_bit(R10BIO_Uptodate, &r10_bio->state))
+               generic_make_request(wbio);
+       else
+               bio_endio(wbio, -EIO);
 }
 
 
@@ -1202,9 +1406,119 @@ static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
  *
  *     1.      Retries failed read operations on working mirrors.
  *     2.      Updates the raid superblock when problems encounter.
- *     3.      Performs writes following reads for array syncronising.
+ *     3.      Performs writes following reads for array synchronising.
  */
 
+static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
+{
+       int sect = 0; /* Offset from r10_bio->sector */
+       int sectors = r10_bio->sectors;
+       mdk_rdev_t*rdev;
+       while(sectors) {
+               int s = sectors;
+               int sl = r10_bio->read_slot;
+               int success = 0;
+               int start;
+
+               if (s > (PAGE_SIZE>>9))
+                       s = PAGE_SIZE >> 9;
+
+               rcu_read_lock();
+               do {
+                       int d = r10_bio->devs[sl].devnum;
+                       rdev = rcu_dereference(conf->mirrors[d].rdev);
+                       if (rdev &&
+                           test_bit(In_sync, &rdev->flags)) {
+                               atomic_inc(&rdev->nr_pending);
+                               rcu_read_unlock();
+                               success = sync_page_io(rdev->bdev,
+                                                      r10_bio->devs[sl].addr +
+                                                      sect + rdev->data_offset,
+                                                      s<<9,
+                                                      conf->tmppage, READ);
+                               rdev_dec_pending(rdev, mddev);
+                               rcu_read_lock();
+                               if (success)
+                                       break;
+                       }
+                       sl++;
+                       if (sl == conf->copies)
+                               sl = 0;
+               } while (!success && sl != r10_bio->read_slot);
+               rcu_read_unlock();
+
+               if (!success) {
+                       /* Cannot read from anywhere -- bye bye array */
+                       int dn = r10_bio->devs[r10_bio->read_slot].devnum;
+                       md_error(mddev, conf->mirrors[dn].rdev);
+                       break;
+               }
+
+               start = sl;
+               /* write it back and re-read */
+               rcu_read_lock();
+               while (sl != r10_bio->read_slot) {
+                       int d;
+                       if (sl==0)
+                               sl = conf->copies;
+                       sl--;
+                       d = r10_bio->devs[sl].devnum;
+                       rdev = rcu_dereference(conf->mirrors[d].rdev);
+                       if (rdev &&
+                           test_bit(In_sync, &rdev->flags)) {
+                               atomic_inc(&rdev->nr_pending);
+                               rcu_read_unlock();
+                               atomic_add(s, &rdev->corrected_errors);
+                               if (sync_page_io(rdev->bdev,
+                                                r10_bio->devs[sl].addr +
+                                                sect + rdev->data_offset,
+                                                s<<9, conf->tmppage, WRITE)
+                                   == 0)
+                                       /* Well, this device is dead */
+                                       md_error(mddev, rdev);
+                               rdev_dec_pending(rdev, mddev);
+                               rcu_read_lock();
+                       }
+               }
+               sl = start;
+               while (sl != r10_bio->read_slot) {
+                       int d;
+                       if (sl==0)
+                               sl = conf->copies;
+                       sl--;
+                       d = r10_bio->devs[sl].devnum;
+                       rdev = rcu_dereference(conf->mirrors[d].rdev);
+                       if (rdev &&
+                           test_bit(In_sync, &rdev->flags)) {
+                               char b[BDEVNAME_SIZE];
+                               atomic_inc(&rdev->nr_pending);
+                               rcu_read_unlock();
+                               if (sync_page_io(rdev->bdev,
+                                                r10_bio->devs[sl].addr +
+                                                sect + rdev->data_offset,
+                                                s<<9, conf->tmppage, READ) == 0)
+                                       /* Well, this device is dead */
+                                       md_error(mddev, rdev);
+                               else
+                                       printk(KERN_INFO
+                                              "raid10:%s: read error corrected"
+                                              " (%d sectors at %llu on %s)\n",
+                                              mdname(mddev), s,
+                                              (unsigned long long)(sect+
+                                                   rdev->data_offset),
+                                              bdevname(rdev->bdev, b));
+
+                               rdev_dec_pending(rdev, mddev);
+                               rcu_read_lock();
+                       }
+               }
+               rcu_read_unlock();
+
+               sectors -= s;
+               sect += s;
+       }
+}
+
 static void raid10d(mddev_t *mddev)
 {
        r10bio_t *r10_bio;
@@ -1216,15 +1530,20 @@ static void raid10d(mddev_t *mddev)
        mdk_rdev_t *rdev;
 
        md_check_recovery(mddev);
-       md_handle_safemode(mddev);
 
        for (;;) {
                char b[BDEVNAME_SIZE];
+
+               unplug += flush_pending_writes(conf);
+
                spin_lock_irqsave(&conf->device_lock, flags);
-               if (list_empty(head))
+               if (list_empty(head)) {
+                       spin_unlock_irqrestore(&conf->device_lock, flags);
                        break;
+               }
                r10_bio = list_entry(head->prev, r10bio_t, retry_list);
                list_del(head->prev);
+               conf->nr_queued--;
                spin_unlock_irqrestore(&conf->device_lock, flags);
 
                mddev = r10_bio->mddev;
@@ -1237,9 +1556,23 @@ static void raid10d(mddev_t *mddev)
                        unplug = 1;
                } else {
                        int mirror;
+                       /* we got a read error. Maybe the drive is bad.  Maybe just
+                        * the block and we can fix it.
+                        * We freeze all other IO, and try reading the block from
+                        * other devices.  When we find one, we re-write
+                        * and check it that fixes the read error.
+                        * This is all done synchronously while the array is
+                        * frozen.
+                        */
+                       if (mddev->ro == 0) {
+                               freeze_array(conf);
+                               fix_read_error(conf, mddev, r10_bio);
+                               unfreeze_array(conf);
+                       }
+
                        bio = r10_bio->devs[r10_bio->read_slot].bio;
-                       r10_bio->devs[r10_bio->read_slot].bio = NULL;
-                       bio_put(bio);
+                       r10_bio->devs[r10_bio->read_slot].bio =
+                               mddev->ro ? IO_BLOCKED : NULL;
                        mirror = read_balance(conf, r10_bio);
                        if (mirror == -1) {
                                printk(KERN_ALERT "raid10: %s: unrecoverable I/O"
@@ -1247,7 +1580,10 @@ static void raid10d(mddev_t *mddev)
                                       bdevname(bio->bi_bdev,b),
                                       (unsigned long long)r10_bio->sector);
                                raid_end_bio_io(r10_bio);
+                               bio_put(bio);
                        } else {
+                               const int do_sync = bio_sync(r10_bio->master_bio);
+                               bio_put(bio);
                                rdev = conf->mirrors[mirror].rdev;
                                if (printk_ratelimit())
                                        printk(KERN_ERR "raid10: %s: redirecting sector %llu to"
@@ -1259,7 +1595,7 @@ static void raid10d(mddev_t *mddev)
                                bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr
                                        + rdev->data_offset;
                                bio->bi_bdev = rdev->bdev;
-                               bio->bi_rw = READ;
+                               bio->bi_rw = READ | do_sync;
                                bio->bi_private = r10_bio;
                                bio->bi_end_io = raid10_end_read_request;
                                unplug = 1;
@@ -1267,7 +1603,6 @@ static void raid10d(mddev_t *mddev)
                        }
                }
        }
-       spin_unlock_irqrestore(&conf->device_lock, flags);
        if (unplug)
                unplug_slaves(mddev);
 }
@@ -1278,8 +1613,7 @@ static int init_resync(conf_t *conf)
        int buffs;
 
        buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
-       if (conf->r10buf_pool)
-               BUG();
+       BUG_ON(conf->r10buf_pool);
        conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
        if (!conf->r10buf_pool)
                return -ENOMEM;
@@ -1319,7 +1653,7 @@ 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;
@@ -1327,31 +1661,59 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
        sector_t max_sector, nr_sectors;
        int disk;
        int i;
+       int max_sync;
+       int sync_blocks;
 
        sector_t sectors_skipped = 0;
        int chunks_skipped = 0;
 
        if (!conf->r10buf_pool)
                if (init_resync(conf))
-                       return -ENOMEM;
+                       return 0;
 
  skipped:
        max_sector = mddev->size << 1;
        if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
                max_sector = mddev->resync_max_sectors;
        if (sector_nr >= max_sector) {
+               /* If we aborted, we need to abort the
+                * sync on the 'current' bitmap chucks (there can
+                * be several when recovering multiple devices).
+                * as we may have started syncing it but not finished.
+                * We can find the current address in
+                * mddev->curr_resync, but for recovery,
+                * we need to convert that to several
+                * virtual addresses.
+                */
+               if (mddev->curr_resync < max_sector) { /* aborted */
+                       if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
+                               bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
+                                               &sync_blocks, 1);
+                       else for (i=0; i<conf->raid_disks; i++) {
+                               sector_t sect =
+                                       raid10_find_virt(conf, mddev->curr_resync, i);
+                               bitmap_end_sync(mddev->bitmap, sect,
+                                               &sync_blocks, 1);
+                       }
+               } else /* completed sync */
+                       conf->fullsync = 0;
+
+               bitmap_close_sync(mddev->bitmap);
                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;
        }
 
+       if (max_sector > mddev->resync_max)
+               max_sector = mddev->resync_max; /* Don't do IO beyond here */
+
        /* make sure whole request will fit in a chunk - if chunks
         * are meaningful
         */
@@ -1362,9 +1724,10 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
         * If there is non-resync activity waiting for us then
         * put in a delay to throttle resync.
         */
-       if (!go_faster && waitqueue_active(&conf->wait_resume))
+       if (!go_faster && conf->nr_waiting)
                msleep_interruptible(1000);
-       device_barrier(conf, sector_nr + RESYNC_SECTORS);
+
+       bitmap_cond_end_sync(mddev->bitmap, sector_nr);
 
        /* Again, very different code for resync and recovery.
         * Both must result in an r10bio with a list of bios that
@@ -1381,6 +1744,7 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
         * end_sync_write if we will want to write.
         */
 
+       max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
        if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
                /* recovery... the complicated one */
                int i, j, k;
@@ -1388,15 +1752,30 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
 
                for (i=0 ; i<conf->raid_disks; i++)
                        if (conf->mirrors[i].rdev &&
-                           !conf->mirrors[i].rdev->in_sync) {
+                           !test_bit(In_sync, &conf->mirrors[i].rdev->flags)) {
+                               int still_degraded = 0;
                                /* want to reconstruct this device */
                                r10bio_t *rb2 = r10_bio;
+                               sector_t sect = raid10_find_virt(conf, sector_nr, i);
+                               int must_sync;
+                               /* Unless we are doing a full sync, we only need
+                                * to recover the block if it is set in the bitmap
+                                */
+                               must_sync = bitmap_start_sync(mddev->bitmap, sect,
+                                                             &sync_blocks, 1);
+                               if (sync_blocks < max_sync)
+                                       max_sync = sync_blocks;
+                               if (!must_sync &&
+                                   !conf->fullsync) {
+                                       /* yep, skip the sync_blocks here, but don't assume
+                                        * that there will never be anything to do here
+                                        */
+                                       chunks_skipped = -1;
+                                       continue;
+                               }
 
                                r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
-                               spin_lock_irq(&conf->resync_lock);
-                               conf->nr_pending++;
-                               if (rb2) conf->barrier++;
-                               spin_unlock_irq(&conf->resync_lock);
+                               raise_barrier(conf, rb2 != NULL);
                                atomic_set(&r10_bio->remaining, 0);
 
                                r10_bio->master_bio = (struct bio*)rb2;
@@ -1404,19 +1783,34 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
                                        atomic_inc(&rb2->remaining);
                                r10_bio->mddev = mddev;
                                set_bit(R10BIO_IsRecover, &r10_bio->state);
-                               r10_bio->sector = raid10_find_virt(conf, sector_nr, i);
+                               r10_bio->sector = sect;
+
                                raid10_find_phys(conf, r10_bio);
+                               /* Need to check if this section will still be
+                                * degraded
+                                */
+                               for (j=0; j<conf->copies;j++) {
+                                       int d = r10_bio->devs[j].devnum;
+                                       if (conf->mirrors[d].rdev == NULL ||
+                                           test_bit(Faulty, &conf->mirrors[d].rdev->flags)) {
+                                               still_degraded = 1;
+                                               break;
+                                       }
+                               }
+                               must_sync = bitmap_start_sync(mddev->bitmap, sect,
+                                                             &sync_blocks, still_degraded);
+
                                for (j=0; j<conf->copies;j++) {
                                        int d = r10_bio->devs[j].devnum;
                                        if (conf->mirrors[d].rdev &&
-                                           conf->mirrors[d].rdev->in_sync) {
+                                           test_bit(In_sync, &conf->mirrors[d].rdev->flags)) {
                                                /* This is where we read from */
                                                bio = r10_bio->devs[0].bio;
                                                bio->bi_next = biolist;
                                                biolist = bio;
                                                bio->bi_private = r10_bio;
                                                bio->bi_end_io = end_sync_read;
-                                               bio->bi_rw = 0;
+                                               bio->bi_rw = READ;
                                                bio->bi_sector = r10_bio->devs[j].addr +
                                                        conf->mirrors[d].rdev->data_offset;
                                                bio->bi_bdev = conf->mirrors[d].rdev->bdev;
@@ -1427,12 +1821,13 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
                                                for (k=0; k<conf->copies; k++)
                                                        if (r10_bio->devs[k].devnum == i)
                                                                break;
+                                               BUG_ON(k == conf->copies);
                                                bio = r10_bio->devs[1].bio;
                                                bio->bi_next = biolist;
                                                biolist = bio;
                                                bio->bi_private = r10_bio;
                                                bio->bi_end_io = end_sync_write;
-                                               bio->bi_rw = 1;
+                                               bio->bi_rw = WRITE;
                                                bio->bi_sector = r10_bio->devs[k].addr +
                                                        conf->mirrors[i].rdev->data_offset;
                                                bio->bi_bdev = conf->mirrors[i].rdev->bdev;
@@ -1444,7 +1839,15 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
                                        }
                                }
                                if (j == conf->copies) {
-                                       BUG();
+                                       /* Cannot recover, so abort the recovery */
+                                       put_buf(r10_bio);
+                                       if (rb2)
+                                               atomic_dec(&rb2->remaining);
+                                       r10_bio = rb2;
+                                       if (!test_and_set_bit(MD_RECOVERY_ERR, &mddev->recovery))
+                                               printk(KERN_INFO "raid10: %s: insufficient working devices for recovery.\n",
+                                                      mdname(mddev));
+                                       break;
                                }
                        }
                if (biolist == NULL) {
@@ -1459,14 +1862,22 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
        } else {
                /* resync. Schedule a read for every block at this virt offset */
                int count = 0;
-               r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
 
-               spin_lock_irq(&conf->resync_lock);
-               conf->nr_pending++;
-               spin_unlock_irq(&conf->resync_lock);
+               if (!bitmap_start_sync(mddev->bitmap, sector_nr,
+                                      &sync_blocks, mddev->degraded) &&
+                   !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
+                       /* We can skip this block */
+                       *skipped = 1;
+                       return sync_blocks + sectors_skipped;
+               }
+               if (sync_blocks < max_sync)
+                       max_sync = sync_blocks;
+               r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
 
                r10_bio->mddev = mddev;
                atomic_set(&r10_bio->remaining, 0);
+               raise_barrier(conf, 0);
+               conf->next_resync = sector_nr;
 
                r10_bio->master_bio = NULL;
                r10_bio->sector = sector_nr;
@@ -1478,8 +1889,9 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
                        int d = r10_bio->devs[i].devnum;
                        bio = r10_bio->devs[i].bio;
                        bio->bi_end_io = NULL;
+                       clear_bit(BIO_UPTODATE, &bio->bi_flags);
                        if (conf->mirrors[d].rdev == NULL ||
-                           conf->mirrors[d].rdev->faulty)
+                           test_bit(Faulty, &conf->mirrors[d].rdev->flags))
                                continue;
                        atomic_inc(&conf->mirrors[d].rdev->nr_pending);
                        atomic_inc(&r10_bio->remaining);
@@ -1487,7 +1899,7 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
                        biolist = bio;
                        bio->bi_private = r10_bio;
                        bio->bi_end_io = end_sync_read;
-                       bio->bi_rw = 0;
+                       bio->bi_rw = READ;
                        bio->bi_sector = r10_bio->devs[i].addr +
                                conf->mirrors[d].rdev->data_offset;
                        bio->bi_bdev = conf->mirrors[d].rdev->bdev;
@@ -1519,6 +1931,8 @@ static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster)
        }
 
        nr_sectors = 0;
+       if (sector_nr + max_sync < max_sector)
+               max_sector = sector_nr + max_sync;
        do {
                struct page *page;
                int len = PAGE_SIZE;
@@ -1563,17 +1977,22 @@ 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;
        }
 }
@@ -1585,18 +2004,19 @@ static int run(mddev_t *mddev)
        mirror_info_t *disk;
        mdk_rdev_t *rdev;
        struct list_head *tmp;
-       int nc, fc;
+       int nc, fc, fo;
        sector_t stride, size;
 
-       if (mddev->level != 10) {
-               printk(KERN_ERR "raid10: %s: raid level not set correctly... (%d)\n",
-                      mdname(mddev), mddev->level);
-               goto out;
+       if (mddev->chunk_size == 0) {
+               printk(KERN_ERR "md/raid10: non-zero chunk size required.\n");
+               return -EINVAL;
        }
+
        nc = mddev->layout & 255;
        fc = (mddev->layout >> 8) & 255;
+       fo = mddev->layout & (1<<16);
        if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks ||
-           (mddev->layout >> 16)) {
+           (mddev->layout >> 17)) {
                printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n",
                       mdname(mddev), mddev->layout);
                goto out;
@@ -1606,30 +2026,52 @@ static int run(mddev_t *mddev)
         * bookkeeping area. [whatever we allocate in run(),
         * should be freed in stop()]
         */
-       conf = kmalloc(sizeof(conf_t), GFP_KERNEL);
+       conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
        mddev->private = conf;
        if (!conf) {
                printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
                        mdname(mddev));
                goto out;
        }
-       memset(conf, 0, sizeof(*conf));
-       conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks,
+       conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
                                 GFP_KERNEL);
        if (!conf->mirrors) {
                printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
                       mdname(mddev));
                goto out_free_conf;
        }
-       memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks);
 
+       conf->tmppage = alloc_page(GFP_KERNEL);
+       if (!conf->tmppage)
+               goto out_free_conf;
+
+       conf->mddev = mddev;
+       conf->raid_disks = mddev->raid_disks;
        conf->near_copies = nc;
        conf->far_copies = fc;
        conf->copies = nc*fc;
+       conf->far_offset = fo;
        conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1;
        conf->chunk_shift = ffz(~mddev->chunk_size) - 9;
-       stride = mddev->size >> (conf->chunk_shift-1);
-       sector_div(stride, fc);
+       size = mddev->size >> (conf->chunk_shift-1);
+       sector_div(size, fc);
+       size = size * conf->raid_disks;
+       sector_div(size, nc);
+       /* 'size' is now the number of chunks in the array */
+       /* calculate "used chunks per device" in 'stride' */
+       stride = size * conf->copies;
+
+       /* We need to round up when dividing by raid_disks to
+        * get the stride size.
+        */
+       stride += conf->raid_disks - 1;
+       sector_div(stride, conf->raid_disks);
+       mddev->size = stride  << (conf->chunk_shift-1);
+
+       if (fo)
+               stride = 1;
+       else
+               sector_div(stride, fc);
        conf->stride = stride << conf->chunk_shift;
 
        conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
@@ -1640,7 +2082,7 @@ static int run(mddev_t *mddev)
                goto out_free_conf;
        }
 
-       ITERATE_RDEV(mddev, rdev, tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                disk_idx = rdev->raid_disk;
                if (disk_idx >= mddev->raid_disks
                    || disk_idx < 0)
@@ -1660,21 +2102,17 @@ static int run(mddev_t *mddev)
                        mddev->queue->max_sectors = (PAGE_SIZE>>9);
 
                disk->head_position = 0;
-               if (!rdev->faulty && rdev->in_sync)
-                       conf->working_disks++;
        }
-       conf->raid_disks = mddev->raid_disks;
-       conf->mddev = mddev;
        spin_lock_init(&conf->device_lock);
        INIT_LIST_HEAD(&conf->retry_list);
 
        spin_lock_init(&conf->resync_lock);
-       init_waitqueue_head(&conf->wait_idle);
-       init_waitqueue_head(&conf->wait_resume);
+       init_waitqueue_head(&conf->wait_barrier);
 
-       if (!conf->working_disks) {
-               printk(KERN_ERR "raid10: no operational mirrors for %s\n",
-                       mdname(mddev));
+       /* need to check that every block has at least one working mirror */
+       if (!enough(conf)) {
+               printk(KERN_ERR "raid10: not enough operational mirrors for %s\n",
+                      mdname(mddev));
                goto out_free_conf;
        }
 
@@ -1683,7 +2121,8 @@ static int run(mddev_t *mddev)
 
                disk = conf->mirrors + i;
 
-               if (!disk->rdev) {
+               if (!disk->rdev ||
+                   !test_bit(In_sync, &disk->rdev->flags)) {
                        disk->head_position = 0;
                        mddev->degraded++;
                }
@@ -1705,20 +2144,19 @@ static int run(mddev_t *mddev)
        /*
         * Ok, everything is just fine now
         */
-       size = conf->stride * conf->raid_disks;
-       sector_div(size, conf->near_copies);
-       mddev->array_size = size/2;
-       mddev->resync_max_sectors = size;
+       mddev->array_size = size << (conf->chunk_shift-1);
+       mddev->resync_max_sectors = size << conf->chunk_shift;
 
        mddev->queue->unplug_fn = raid10_unplug;
-       mddev->queue->issue_flush_fn = raid10_issue_flush;
+       mddev->queue->backing_dev_info.congested_fn = raid10_congested;
+       mddev->queue->backing_dev_info.congested_data = mddev;
 
        /* Calculate max read-ahead size.
         * We need to readahead at least twice a whole stripe....
         * maybe...
         */
        {
-               int stripe = conf->raid_disks * mddev->chunk_size / PAGE_CACHE_SIZE;
+               int stripe = conf->raid_disks * (mddev->chunk_size / PAGE_SIZE);
                stripe /= conf->near_copies;
                if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
                        mddev->queue->backing_dev_info.ra_pages = 2* stripe;
@@ -1731,8 +2169,8 @@ static int run(mddev_t *mddev)
 out_free_conf:
        if (conf->r10bio_pool)
                mempool_destroy(conf->r10bio_pool);
-       if (conf->mirrors)
-               kfree(conf->mirrors);
+       safe_put_page(conf->tmppage);
+       kfree(conf->mirrors);
        kfree(conf);
        mddev->private = NULL;
 out:
@@ -1748,17 +2186,37 @@ 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;
 }
 
+static void raid10_quiesce(mddev_t *mddev, int state)
+{
+       conf_t *conf = mddev_to_conf(mddev);
+
+       switch(state) {
+       case 1:
+               raise_barrier(conf, 0);
+               break;
+       case 0:
+               lower_barrier(conf);
+               break;
+       }
+       if (mddev->thread) {
+               if (mddev->bitmap)
+                       mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
+               else
+                       mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
+               md_wakeup_thread(mddev->thread);
+       }
+}
 
-static mdk_personality_t raid10_personality =
+static struct mdk_personality raid10_personality =
 {
        .name           = "raid10",
+       .level          = 10,
        .owner          = THIS_MODULE,
        .make_request   = make_request,
        .run            = run,
@@ -1769,19 +2227,22 @@ static mdk_personality_t raid10_personality =
        .hot_remove_disk= raid10_remove_disk,
        .spare_active   = raid10_spare_active,
        .sync_request   = sync_request,
+       .quiesce        = raid10_quiesce,
 };
 
 static int __init raid_init(void)
 {
-       return register_md_personality(RAID10, &raid10_personality);
+       return register_md_personality(&raid10_personality);
 }
 
 static void raid_exit(void)
 {
-       unregister_md_personality(RAID10);
+       unregister_md_personality(&raid10_personality);
 }
 
 module_init(raid_init);
 module_exit(raid_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-9"); /* RAID10 */
+MODULE_ALIAS("md-raid10");
+MODULE_ALIAS("md-level-10");