]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - drivers/md/md.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
[linux-2.6-omap-h63xx.git] / drivers / md / md.c
index c28a120b4161ea7324eae5160ed2a4c2fc7e0ab6..bb3e4b1cb7738659a25a4ad15bb314957d861173 100644 (file)
@@ -195,7 +195,7 @@ static DEFINE_SPINLOCK(all_mddevs_lock);
  * Any code which breaks out of this loop while own
  * a reference to the current mddev and must mddev_put it.
  */
-#define ITERATE_MDDEV(mddev,tmp)                                       \
+#define for_each_mddev(mddev,tmp)                                      \
                                                                        \
        for (({ spin_lock(&all_mddevs_lock);                            \
                tmp = all_mddevs.next;                                  \
@@ -275,13 +275,15 @@ static mddev_t * mddev_find(dev_t unit)
        spin_lock_init(&new->write_lock);
        init_waitqueue_head(&new->sb_wait);
        new->reshape_position = MaxSector;
+       new->resync_max = MaxSector;
 
        new->queue = blk_alloc_queue(GFP_KERNEL);
        if (!new->queue) {
                kfree(new);
                return NULL;
        }
-       set_bit(QUEUE_FLAG_CLUSTER, &new->queue->queue_flags);
+       /* Can be unlocked because the queue is new: no concurrency */
+       queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, new->queue);
 
        blk_queue_make_request(new->queue, md_fail_request);
 
@@ -310,7 +312,7 @@ static mdk_rdev_t * find_rdev_nr(mddev_t *mddev, int nr)
        mdk_rdev_t * rdev;
        struct list_head *tmp;
 
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                if (rdev->desc_nr == nr)
                        return rdev;
        }
@@ -322,7 +324,7 @@ static mdk_rdev_t * find_rdev(mddev_t * mddev, dev_t dev)
        struct list_head *tmp;
        mdk_rdev_t *rdev;
 
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                if (rdev->bdev->bd_dev == dev)
                        return rdev;
        }
@@ -730,9 +732,9 @@ static int super_90_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version
        else
                rdev->desc_nr = sb->this_disk.number;
 
-       if (refdev == 0)
+       if (!refdev) {
                ret = 1;
-       else {
+       else {
                __u64 ev1, ev2;
                mdp_super_t *refsb = (mdp_super_t*)page_address(refdev->sb_page);
                if (!uuid_equal(refsb, sb)) {
@@ -773,12 +775,16 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
        __u64 ev1 = md_event(sb);
 
        rdev->raid_disk = -1;
-       rdev->flags = 0;
+       clear_bit(Faulty, &rdev->flags);
+       clear_bit(In_sync, &rdev->flags);
+       clear_bit(WriteMostly, &rdev->flags);
+       clear_bit(BarriersNotsupp, &rdev->flags);
+
        if (mddev->raid_disks == 0) {
                mddev->major_version = 0;
                mddev->minor_version = sb->minor_version;
                mddev->patch_version = sb->patch_version;
-               mddev->persistent = ! sb->not_persistent;
+               mddev->external = 0;
                mddev->chunk_size = sb->chunk_size;
                mddev->ctime = sb->ctime;
                mddev->utime = sb->utime;
@@ -904,7 +910,7 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
        sb->size  = mddev->size;
        sb->raid_disks = mddev->raid_disks;
        sb->md_minor = mddev->md_minor;
-       sb->not_persistent = !mddev->persistent;
+       sb->not_persistent = 0;
        sb->utime = mddev->utime;
        sb->state = 0;
        sb->events_hi = (mddev->events>>32);
@@ -938,7 +944,7 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
                sb->state |= (1<<MD_SB_BITMAP_PRESENT);
 
        sb->disks[0].state = (1<<MD_DISK_REMOVED);
-       ITERATE_RDEV(mddev,rdev2,tmp) {
+       rdev_for_each(rdev2, tmp, mddev) {
                mdp_disk_t *d;
                int desc_nr;
                if (rdev2->raid_disk >= 0 && test_bit(In_sync, &rdev2->flags)
@@ -1100,16 +1106,20 @@ static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
        rdev->sb_size = le32_to_cpu(sb->max_dev) * 2 + 256;
        bmask = queue_hardsect_size(rdev->bdev->bd_disk->queue)-1;
        if (rdev->sb_size & bmask)
-               rdev-> sb_size = (rdev->sb_size | bmask)+1;
+               rdev->sb_size = (rdev->sb_size | bmask) + 1;
+
+       if (minor_version
+           && rdev->data_offset < sb_offset + (rdev->sb_size/512))
+               return -EINVAL;
 
        if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
                rdev->desc_nr = -1;
        else
                rdev->desc_nr = le32_to_cpu(sb->dev_number);
 
-       if (refdev == 0)
+       if (!refdev) {
                ret = 1;
-       else {
+       else {
                __u64 ev1, ev2;
                struct mdp_superblock_1 *refsb = 
                        (struct mdp_superblock_1*)page_address(refdev->sb_page);
@@ -1132,7 +1142,7 @@ static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
                else
                        ret = 0;
        }
-       if (minor_version) 
+       if (minor_version)
                rdev->size = ((rdev->bdev->bd_inode->i_size>>9) - le64_to_cpu(sb->data_offset)) / 2;
        else
                rdev->size = rdev->sb_offset;
@@ -1153,11 +1163,15 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
        __u64 ev1 = le64_to_cpu(sb->events);
 
        rdev->raid_disk = -1;
-       rdev->flags = 0;
+       clear_bit(Faulty, &rdev->flags);
+       clear_bit(In_sync, &rdev->flags);
+       clear_bit(WriteMostly, &rdev->flags);
+       clear_bit(BarriersNotsupp, &rdev->flags);
+
        if (mddev->raid_disks == 0) {
                mddev->major_version = 1;
                mddev->patch_version = 0;
-               mddev->persistent = 1;
+               mddev->external = 0;
                mddev->chunk_size = le32_to_cpu(sb->chunksize) << 9;
                mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
                mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
@@ -1286,7 +1300,7 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
        }
 
        max_dev = 0;
-       ITERATE_RDEV(mddev,rdev2,tmp)
+       rdev_for_each(rdev2, tmp, mddev)
                if (rdev2->desc_nr+1 > max_dev)
                        max_dev = rdev2->desc_nr+1;
 
@@ -1295,7 +1309,7 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
        for (i=0; i<max_dev;i++)
                sb->dev_roles[i] = cpu_to_le16(0xfffe);
        
-       ITERATE_RDEV(mddev,rdev2,tmp) {
+       rdev_for_each(rdev2, tmp, mddev) {
                i = rdev2->desc_nr;
                if (test_bit(Faulty, &rdev2->flags))
                        sb->dev_roles[i] = cpu_to_le16(0xfffe);
@@ -1333,8 +1347,8 @@ static int match_mddev_units(mddev_t *mddev1, mddev_t *mddev2)
        struct list_head *tmp, *tmp2;
        mdk_rdev_t *rdev, *rdev2;
 
-       ITERATE_RDEV(mddev1,rdev,tmp)
-               ITERATE_RDEV(mddev2, rdev2, tmp2)
+       rdev_for_each(rdev, tmp, mddev1)
+               rdev_for_each(rdev2, tmp2, mddev2)
                        if (rdev->bdev->bd_contains ==
                            rdev2->bdev->bd_contains)
                                return 1;
@@ -1401,7 +1415,7 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
                goto fail;
        }
        list_add(&rdev->same_set, &mddev->disks);
-       bd_claim_by_disk(rdev->bdev, rdev, mddev->gendisk);
+       bd_claim_by_disk(rdev->bdev, rdev->bdev->bd_holder, mddev->gendisk);
        return 0;
 
  fail:
@@ -1410,10 +1424,11 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
        return err;
 }
 
-static void delayed_delete(struct work_struct *ws)
+static void md_delayed_delete(struct work_struct *ws)
 {
        mdk_rdev_t *rdev = container_of(ws, mdk_rdev_t, del_work);
        kobject_del(&rdev->kobj);
+       kobject_put(&rdev->kobj);
 }
 
 static void unbind_rdev_from_array(mdk_rdev_t * rdev)
@@ -1432,7 +1447,8 @@ static void unbind_rdev_from_array(mdk_rdev_t * rdev)
        /* We need to delay this, otherwise we can deadlock when
         * writing to 'remove' to "dev/state"
         */
-       INIT_WORK(&rdev->del_work, delayed_delete);
+       INIT_WORK(&rdev->del_work, md_delayed_delete);
+       kobject_get(&rdev->kobj);
        schedule_work(&rdev->del_work);
 }
 
@@ -1441,7 +1457,7 @@ static void unbind_rdev_from_array(mdk_rdev_t * rdev)
  * otherwise reused by a RAID array (or any other kernel
  * subsystem), by bd_claiming the device.
  */
-static int lock_rdev(mdk_rdev_t *rdev, dev_t dev)
+static int lock_rdev(mdk_rdev_t *rdev, dev_t dev, int shared)
 {
        int err = 0;
        struct block_device *bdev;
@@ -1453,13 +1469,15 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev)
                        __bdevname(dev, b));
                return PTR_ERR(bdev);
        }
-       err = bd_claim(bdev, rdev);
+       err = bd_claim(bdev, shared ? (mdk_rdev_t *)lock_rdev : rdev);
        if (err) {
                printk(KERN_ERR "md: could not bd_claim %s.\n",
                        bdevname(bdev, b));
                blkdev_put(bdev);
                return err;
        }
+       if (!shared)
+               set_bit(AllReserved, &rdev->flags);
        rdev->bdev = bdev;
        return err;
 }
@@ -1486,7 +1504,8 @@ static void export_rdev(mdk_rdev_t * rdev)
        free_disk_sb(rdev);
        list_del_init(&rdev->same_set);
 #ifndef MODULE
-       md_autodetect_dev(rdev->bdev->bd_dev);
+       if (test_bit(AutoDetected, &rdev->flags))
+               md_autodetect_dev(rdev->bdev->bd_dev);
 #endif
        unlock_rdev(rdev);
        kobject_put(&rdev->kobj);
@@ -1503,7 +1522,7 @@ static void export_array(mddev_t *mddev)
        struct list_head *tmp;
        mdk_rdev_t *rdev;
 
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                if (!rdev->mddev) {
                        MD_BUG();
                        continue;
@@ -1581,17 +1600,17 @@ static void md_print_devices(void)
        printk("md:     **********************************\n");
        printk("md:     * <COMPLETE RAID STATE PRINTOUT> *\n");
        printk("md:     **********************************\n");
-       ITERATE_MDDEV(mddev,tmp) {
+       for_each_mddev(mddev, tmp) {
 
                if (mddev->bitmap)
                        bitmap_print_sb(mddev->bitmap);
                else
                        printk("%s: ", mdname(mddev));
-               ITERATE_RDEV(mddev,rdev,tmp2)
+               rdev_for_each(rdev, tmp2, mddev)
                        printk("<%s>", bdevname(rdev->bdev,b));
                printk("\n");
 
-               ITERATE_RDEV(mddev,rdev,tmp2)
+               rdev_for_each(rdev, tmp2, mddev)
                        print_rdev(rdev);
        }
        printk("md:     **********************************\n");
@@ -1610,7 +1629,7 @@ static void sync_sbs(mddev_t * mddev, int nospares)
        mdk_rdev_t *rdev;
        struct list_head *tmp;
 
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                if (rdev->sb_events == mddev->events ||
                    (nospares &&
                     rdev->raid_disk < 0 &&
@@ -1696,18 +1715,20 @@ repeat:
                MD_BUG();
                mddev->events --;
        }
-       sync_sbs(mddev, nospares);
 
        /*
         * do not write anything to disk if using
         * nonpersistent superblocks
         */
        if (!mddev->persistent) {
-               clear_bit(MD_CHANGE_PENDING, &mddev->flags);
+               if (!mddev->external)
+                       clear_bit(MD_CHANGE_PENDING, &mddev->flags);
+
                spin_unlock_irq(&mddev->write_lock);
                wake_up(&mddev->sb_wait);
                return;
        }
+       sync_sbs(mddev, nospares);
        spin_unlock_irq(&mddev->write_lock);
 
        dprintk(KERN_INFO 
@@ -1715,7 +1736,7 @@ repeat:
                mdname(mddev),mddev->in_sync);
 
        bitmap_update_sb(mddev->bitmap);
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                char b[BDEVNAME_SIZE];
                dprintk(KERN_INFO "md: ");
                if (rdev->sb_loaded != 1)
@@ -1785,7 +1806,7 @@ static ssize_t
 state_show(mdk_rdev_t *rdev, char *page)
 {
        char *sep = "";
-       int len=0;
+       size_t len = 0;
 
        if (test_bit(Faulty, &rdev->flags)) {
                len+= sprintf(page+len, "%sfaulty",sep);
@@ -1843,17 +1864,6 @@ state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
 static struct rdev_sysfs_entry rdev_state =
 __ATTR(state, S_IRUGO|S_IWUSR, state_show, state_store);
 
-static ssize_t
-super_show(mdk_rdev_t *rdev, char *page)
-{
-       if (rdev->sb_loaded && rdev->sb_size) {
-               memcpy(page, page_address(rdev->sb_page), rdev->sb_size);
-               return rdev->sb_size;
-       } else
-               return 0;
-}
-static struct rdev_sysfs_entry rdev_super = __ATTR_RO(super);
-
 static ssize_t
 errors_show(mdk_rdev_t *rdev, char *page)
 {
@@ -1887,20 +1897,45 @@ static ssize_t
 slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
 {
        char *e;
+       int err;
+       char nm[20];
        int slot = simple_strtoul(buf, &e, 10);
        if (strncmp(buf, "none", 4)==0)
                slot = -1;
        else if (e==buf || (*e && *e!= '\n'))
                return -EINVAL;
-       if (rdev->mddev->pers)
-               /* Cannot set slot in active array (yet) */
-               return -EBUSY;
-       if (slot >= rdev->mddev->raid_disks)
-               return -ENOSPC;
-       rdev->raid_disk = slot;
-       /* assume it is working */
-       rdev->flags = 0;
-       set_bit(In_sync, &rdev->flags);
+       if (rdev->mddev->pers) {
+               /* Setting 'slot' on an active array requires also
+                * updating the 'rd%d' link, and communicating
+                * with the personality with ->hot_*_disk.
+                * For now we only support removing
+                * failed/spare devices.  This normally happens automatically,
+                * but not when the metadata is externally managed.
+                */
+               if (slot != -1)
+                       return -EBUSY;
+               if (rdev->raid_disk == -1)
+                       return -EEXIST;
+               /* personality does all needed checks */
+               if (rdev->mddev->pers->hot_add_disk == NULL)
+                       return -EINVAL;
+               err = rdev->mddev->pers->
+                       hot_remove_disk(rdev->mddev, rdev->raid_disk);
+               if (err)
+                       return err;
+               sprintf(nm, "rd%d", rdev->raid_disk);
+               sysfs_remove_link(&rdev->mddev->kobj, nm);
+               set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
+               md_wakeup_thread(rdev->mddev->thread);
+       } else {
+               if (slot >= rdev->mddev->raid_disks)
+                       return -ENOSPC;
+               rdev->raid_disk = slot;
+               /* assume it is working */
+               clear_bit(Faulty, &rdev->flags);
+               clear_bit(WriteMostly, &rdev->flags);
+               set_bit(In_sync, &rdev->flags);
+       }
        return len;
 }
 
@@ -1923,6 +1958,10 @@ offset_store(mdk_rdev_t *rdev, const char *buf, size_t len)
                return -EINVAL;
        if (rdev->mddev->pers)
                return -EBUSY;
+       if (rdev->size && rdev->mddev->external)
+               /* Must set offset before size, so overlap checks
+                * can be sane */
+               return -EBUSY;
        rdev->data_offset = offset;
        return len;
 }
@@ -1936,18 +1975,73 @@ rdev_size_show(mdk_rdev_t *rdev, char *page)
        return sprintf(page, "%llu\n", (unsigned long long)rdev->size);
 }
 
+static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
+{
+       /* check if two start/length pairs overlap */
+       if (s1+l1 <= s2)
+               return 0;
+       if (s2+l2 <= s1)
+               return 0;
+       return 1;
+}
+
 static ssize_t
 rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
 {
        char *e;
        unsigned long long size = simple_strtoull(buf, &e, 10);
+       unsigned long long oldsize = rdev->size;
+       mddev_t *my_mddev = rdev->mddev;
+
        if (e==buf || (*e && *e != '\n'))
                return -EINVAL;
-       if (rdev->mddev->pers)
+       if (my_mddev->pers)
                return -EBUSY;
        rdev->size = size;
-       if (size < rdev->mddev->size || rdev->mddev->size == 0)
-               rdev->mddev->size = size;
+       if (size > oldsize && rdev->mddev->external) {
+               /* need to check that all other rdevs with the same ->bdev
+                * do not overlap.  We need to unlock the mddev to avoid
+                * a deadlock.  We have already changed rdev->size, and if
+                * we have to change it back, we will have the lock again.
+                */
+               mddev_t *mddev;
+               int overlap = 0;
+               struct list_head *tmp, *tmp2;
+
+               mddev_unlock(my_mddev);
+               for_each_mddev(mddev, tmp) {
+                       mdk_rdev_t *rdev2;
+
+                       mddev_lock(mddev);
+                       rdev_for_each(rdev2, tmp2, mddev)
+                               if (test_bit(AllReserved, &rdev2->flags) ||
+                                   (rdev->bdev == rdev2->bdev &&
+                                    rdev != rdev2 &&
+                                    overlaps(rdev->data_offset, rdev->size,
+                                           rdev2->data_offset, rdev2->size))) {
+                                       overlap = 1;
+                                       break;
+                               }
+                       mddev_unlock(mddev);
+                       if (overlap) {
+                               mddev_put(mddev);
+                               break;
+                       }
+               }
+               mddev_lock(my_mddev);
+               if (overlap) {
+                       /* Someone else could have slipped in a size
+                        * change here, but doing so is just silly.
+                        * We put oldsize back because we *know* it is
+                        * safe, and trust userspace not to race with
+                        * itself
+                        */
+                       rdev->size = oldsize;
+                       return -EBUSY;
+               }
+       }
+       if (size < my_mddev->size || my_mddev->size == 0)
+               my_mddev->size = size;
        return len;
 }
 
@@ -1956,7 +2050,6 @@ __ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);
 
 static struct attribute *rdev_default_attrs[] = {
        &rdev_state.attr,
-       &rdev_super.attr,
        &rdev_errors.attr,
        &rdev_slot.attr,
        &rdev_offset.attr,
@@ -1968,10 +2061,21 @@ rdev_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 {
        struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
        mdk_rdev_t *rdev = container_of(kobj, mdk_rdev_t, kobj);
+       mddev_t *mddev = rdev->mddev;
+       ssize_t rv;
 
        if (!entry->show)
                return -EIO;
-       return entry->show(rdev, page);
+
+       rv = mddev ? mddev_lock(mddev) : -EBUSY;
+       if (!rv) {
+               if (rdev->mddev == NULL)
+                       rv = -EBUSY;
+               else
+                       rv = entry->show(rdev, page);
+               mddev_unlock(mddev);
+       }
+       return rv;
 }
 
 static ssize_t
@@ -1980,12 +2084,22 @@ rdev_attr_store(struct kobject *kobj, struct attribute *attr,
 {
        struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
        mdk_rdev_t *rdev = container_of(kobj, mdk_rdev_t, kobj);
+       ssize_t rv;
+       mddev_t *mddev = rdev->mddev;
 
        if (!entry->store)
                return -EIO;
        if (!capable(CAP_SYS_ADMIN))
                return -EACCES;
-       return entry->store(rdev, page, length);
+       rv = mddev ? mddev_lock(mddev): -EBUSY;
+       if (!rv) {
+               if (rdev->mddev == NULL)
+                       rv = -EBUSY;
+               else
+                       rv = entry->store(rdev, page, length);
+               mddev_unlock(rdev->mddev);
+       }
+       return rv;
 }
 
 static void rdev_free(struct kobject *ko)
@@ -2029,7 +2143,7 @@ static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_mi
        if ((err = alloc_disk_sb(rdev)))
                goto abort_free;
 
-       err = lock_rdev(rdev, newdev);
+       err = lock_rdev(rdev, newdev, super_format == -2);
        if (err)
                goto abort_free;
 
@@ -2099,7 +2213,7 @@ static void analyze_sbs(mddev_t * mddev)
        char b[BDEVNAME_SIZE];
 
        freshest = NULL;
-       ITERATE_RDEV(mddev,rdev,tmp)
+       rdev_for_each(rdev, tmp, mddev)
                switch (super_types[mddev->major_version].
                        load_super(rdev, freshest, mddev->minor_version)) {
                case 1:
@@ -2120,7 +2234,7 @@ static void analyze_sbs(mddev_t * mddev)
                validate_super(mddev, freshest);
 
        i = 0;
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                if (rdev != freshest)
                        if (super_types[mddev->major_version].
                            validate_super(mddev, rdev)) {
@@ -2215,7 +2329,7 @@ level_show(mddev_t *mddev, char *page)
 static ssize_t
 level_store(mddev_t *mddev, const char *buf, size_t len)
 {
-       int rv = len;
+       ssize_t rv = len;
        if (mddev->pers)
                return -EBUSY;
        if (len == 0)
@@ -2425,6 +2539,8 @@ array_state_show(mddev_t *mddev, char *page)
                case 0:
                        if (mddev->in_sync)
                                st = clean;
+                       else if (test_bit(MD_CHANGE_CLEAN, &mddev->flags))
+                               st = write_pending;
                        else if (mddev->safemode)
                                st = active_idle;
                        else
@@ -2455,11 +2571,9 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
                break;
        case clear:
                /* stopping an active array */
-               if (mddev->pers) {
-                       if (atomic_read(&mddev->active) > 1)
-                               return -EBUSY;
-                       err = do_md_stop(mddev, 0);
-               }
+               if (atomic_read(&mddev->active) > 1)
+                       return -EBUSY;
+               err = do_md_stop(mddev, 0);
                break;
        case inactive:
                /* stopping an active array */
@@ -2467,7 +2581,8 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
                        if (atomic_read(&mddev->active) > 1)
                                return -EBUSY;
                        err = do_md_stop(mddev, 2);
-               }
+               } else
+                       err = 0; /* already inactive */
                break;
        case suspended:
                break; /* not supported yet */
@@ -2495,9 +2610,15 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
                        restart_array(mddev);
                        spin_lock_irq(&mddev->write_lock);
                        if (atomic_read(&mddev->writes_pending) == 0) {
-                               mddev->in_sync = 1;
-                               set_bit(MD_CHANGE_CLEAN, &mddev->flags);
-                       }
+                               if (mddev->in_sync == 0) {
+                                       mddev->in_sync = 1;
+                                       if (mddev->persistent)
+                                               set_bit(MD_CHANGE_CLEAN,
+                                                       &mddev->flags);
+                               }
+                               err = 0;
+                       } else
+                               err = -EBUSY;
                        spin_unlock_irq(&mddev->write_lock);
                } else {
                        mddev->ro = 0;
@@ -2508,7 +2629,8 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
        case active:
                if (mddev->pers) {
                        restart_array(mddev);
-                       clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
+                       if (mddev->external)
+                               clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
                        wake_up(&mddev->sb_wait);
                        err = 0;
                } else {
@@ -2574,7 +2696,9 @@ new_dev_store(mddev_t *mddev, const char *buf, size_t len)
                        if (err < 0)
                                goto out;
                }
-       } else
+       } else if (mddev->external)
+               rdev = md_import_device(dev, -2, -1);
+       else
                rdev = md_import_device(dev, -1, -1);
 
        if (IS_ERR(rdev))
@@ -2659,7 +2783,9 @@ __ATTR(component_size, S_IRUGO|S_IWUSR, size_show, size_store);
 
 
 /* Metdata version.
- * This is either 'none' for arrays with externally managed metadata,
+ * This is one of
+ *   'none' for arrays with no metadata (good luck...)
+ *   'external' for arrays with externally managed metadata,
  * or N.M for internally known formats
  */
 static ssize_t
@@ -2668,6 +2794,8 @@ metadata_show(mddev_t *mddev, char *page)
        if (mddev->persistent)
                return sprintf(page, "%d.%d\n",
                               mddev->major_version, mddev->minor_version);
+       else if (mddev->external)
+               return sprintf(page, "external:%s\n", mddev->metadata_type);
        else
                return sprintf(page, "none\n");
 }
@@ -2682,6 +2810,21 @@ metadata_store(mddev_t *mddev, const char *buf, size_t len)
 
        if (cmd_match(buf, "none")) {
                mddev->persistent = 0;
+               mddev->external = 0;
+               mddev->major_version = 0;
+               mddev->minor_version = 90;
+               return len;
+       }
+       if (strncmp(buf, "external:", 9) == 0) {
+               size_t namelen = len-9;
+               if (namelen >= sizeof(mddev->metadata_type))
+                       namelen = sizeof(mddev->metadata_type)-1;
+               strncpy(mddev->metadata_type, buf+9, namelen);
+               mddev->metadata_type[namelen] = 0;
+               if (namelen && mddev->metadata_type[namelen-1] == '\n')
+                       mddev->metadata_type[--namelen] = 0;
+               mddev->persistent = 0;
+               mddev->external = 1;
                mddev->major_version = 0;
                mddev->minor_version = 90;
                return len;
@@ -2698,6 +2841,7 @@ metadata_store(mddev_t *mddev, const char *buf, size_t len)
        mddev->major_version = major;
        mddev->minor_version = minor;
        mddev->persistent = 1;
+       mddev->external = 0;
        return len;
 }
 
@@ -2864,6 +3008,43 @@ sync_completed_show(mddev_t *mddev, char *page)
 
 static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);
 
+static ssize_t
+max_sync_show(mddev_t *mddev, char *page)
+{
+       if (mddev->resync_max == MaxSector)
+               return sprintf(page, "max\n");
+       else
+               return sprintf(page, "%llu\n",
+                              (unsigned long long)mddev->resync_max);
+}
+static ssize_t
+max_sync_store(mddev_t *mddev, const char *buf, size_t len)
+{
+       if (strncmp(buf, "max", 3) == 0)
+               mddev->resync_max = MaxSector;
+       else {
+               char *ep;
+               unsigned long long max = simple_strtoull(buf, &ep, 10);
+               if (ep == buf || (*ep != 0 && *ep != '\n'))
+                       return -EINVAL;
+               if (max < mddev->resync_max &&
+                   test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
+                       return -EBUSY;
+
+               /* Must be a multiple of chunk_size */
+               if (mddev->chunk_size) {
+                       if (max & (sector_t)((mddev->chunk_size>>9)-1))
+                               return -EINVAL;
+               }
+               mddev->resync_max = max;
+       }
+       wake_up(&mddev->recovery_wait);
+       return len;
+}
+
+static struct md_sysfs_entry md_max_sync =
+__ATTR(sync_max, S_IRUGO|S_IWUSR, max_sync_show, max_sync_store);
+
 static ssize_t
 suspend_lo_show(mddev_t *mddev, char *page)
 {
@@ -2974,6 +3155,7 @@ static struct attribute *md_redundancy_attrs[] = {
        &md_sync_max.attr,
        &md_sync_speed.attr,
        &md_sync_completed.attr,
+       &md_max_sync.attr,
        &md_suspend_lo.attr,
        &md_suspend_hi.attr,
        &md_bitmap.attr,
@@ -3118,8 +3300,11 @@ static int do_md_run(mddev_t * mddev)
        /*
         * Analyze all RAID superblock(s)
         */
-       if (!mddev->raid_disks)
+       if (!mddev->raid_disks) {
+               if (!mddev->persistent)
+                       return -EINVAL;
                analyze_sbs(mddev);
+       }
 
        chunk_size = mddev->chunk_size;
 
@@ -3143,7 +3328,7 @@ static int do_md_run(mddev_t * mddev)
                }
 
                /* devices must have minimum size of one chunk */
-               ITERATE_RDEV(mddev,rdev,tmp) {
+               rdev_for_each(rdev, tmp, mddev) {
                        if (test_bit(Faulty, &rdev->flags))
                                continue;
                        if (rdev->size < chunk_size / 1024) {
@@ -3170,7 +3355,7 @@ static int do_md_run(mddev_t * mddev)
         * the only valid external interface is through the md
         * device.
         */
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                if (test_bit(Faulty, &rdev->flags))
                        continue;
                sync_blockdev(rdev->bdev);
@@ -3236,8 +3421,8 @@ static int do_md_run(mddev_t * mddev)
                mdk_rdev_t *rdev2;
                struct list_head *tmp2;
                int warned = 0;
-               ITERATE_RDEV(mddev, rdev, tmp) {
-                       ITERATE_RDEV(mddev, rdev2, tmp2) {
+               rdev_for_each(rdev, tmp, mddev) {
+                       rdev_for_each(rdev2, tmp2, mddev) {
                                if (rdev < rdev2 &&
                                    rdev->bdev->bd_contains ==
                                    rdev2->bdev->bd_contains) {
@@ -3297,7 +3482,7 @@ static int do_md_run(mddev_t * mddev)
        mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
        mddev->in_sync = 1;
 
-       ITERATE_RDEV(mddev,rdev,tmp)
+       rdev_for_each(rdev, tmp, mddev)
                if (rdev->raid_disk >= 0) {
                        char nm[20];
                        sprintf(nm, "rd%d", rdev->raid_disk);
@@ -3330,7 +3515,7 @@ static int do_md_run(mddev_t * mddev)
        if (mddev->degraded && !mddev->sync_thread) {
                struct list_head *rtmp;
                int spares = 0;
-               ITERATE_RDEV(mddev,rdev,rtmp)
+               rdev_for_each(rdev, rtmp, mddev)
                        if (rdev->raid_disk >= 0 &&
                            !test_bit(In_sync, &rdev->flags) &&
                            !test_bit(Faulty, &rdev->flags))
@@ -3507,14 +3692,14 @@ static int do_md_stop(mddev_t * mddev, int mode)
                }
                mddev->bitmap_offset = 0;
 
-               ITERATE_RDEV(mddev,rdev,tmp)
+               rdev_for_each(rdev, tmp, mddev)
                        if (rdev->raid_disk >= 0) {
                                char nm[20];
                                sprintf(nm, "rd%d", rdev->raid_disk);
                                sysfs_remove_link(&mddev->kobj, nm);
                        }
 
-               /* make sure all delayed_delete calls have finished */
+               /* make sure all md_delayed_delete calls have finished */
                flush_scheduled_work();
 
                export_array(mddev);
@@ -3523,7 +3708,10 @@ static int do_md_stop(mddev_t * mddev, int mode)
                mddev->size = 0;
                mddev->raid_disks = 0;
                mddev->recovery_cp = 0;
+               mddev->resync_max = MaxSector;
                mddev->reshape_position = MaxSector;
+               mddev->external = 0;
+               mddev->persistent = 0;
 
        } else if (mddev->pers)
                printk(KERN_INFO "md: %s switched to read-only mode.\n",
@@ -3546,7 +3734,7 @@ static void autorun_array(mddev_t *mddev)
 
        printk(KERN_INFO "md: running: ");
 
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                char b[BDEVNAME_SIZE];
                printk("<%s>", bdevname(rdev->bdev,b));
        }
@@ -3589,7 +3777,7 @@ static void autorun_devices(int part)
                printk(KERN_INFO "md: considering %s ...\n",
                        bdevname(rdev0->bdev,b));
                INIT_LIST_HEAD(&candidates);
-               ITERATE_RDEV_PENDING(rdev,tmp)
+               rdev_for_each_list(rdev, tmp, pending_raid_disks)
                        if (super_90_load(rdev, rdev0, 0) >= 0) {
                                printk(KERN_INFO "md:  adding %s ...\n",
                                        bdevname(rdev->bdev,b));
@@ -3632,7 +3820,8 @@ static void autorun_devices(int part)
                        mddev_unlock(mddev);
                } else {
                        printk(KERN_INFO "md: created %s\n", mdname(mddev));
-                       ITERATE_RDEV_GENERIC(candidates,rdev,tmp) {
+                       mddev->persistent = 1;
+                       rdev_for_each_list(rdev, tmp, candidates) {
                                list_del_init(&rdev->same_set);
                                if (bind_rdev_to_array(rdev, mddev))
                                        export_rdev(rdev);
@@ -3643,7 +3832,7 @@ static void autorun_devices(int part)
                /* on success, candidates will be empty, on error
                 * it won't...
                 */
-               ITERATE_RDEV_GENERIC(candidates,rdev,tmp)
+               rdev_for_each_list(rdev, tmp, candidates)
                        export_rdev(rdev);
                mddev_put(mddev);
        }
@@ -3673,7 +3862,7 @@ static int get_array_info(mddev_t * mddev, void __user * arg)
        struct list_head *tmp;
 
        nr=working=active=failed=spare=0;
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                nr++;
                if (test_bit(Faulty, &rdev->flags))
                        failed++;
@@ -3919,8 +4108,6 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
                else
                        rdev->raid_disk = -1;
 
-               rdev->flags = 0;
-
                if (rdev->raid_disk < mddev->raid_disks)
                        if (info->state & (1<<MD_DISK_SYNC))
                                set_bit(In_sync, &rdev->flags);
@@ -3966,7 +4153,7 @@ static int hot_remove_disk(mddev_t * mddev, dev_t dev)
 
        return 0;
 busy:
-       printk(KERN_WARNING "md: cannot remove active disk %s from %s ... \n",
+       printk(KERN_WARNING "md: cannot remove active disk %s from %s ...\n",
                bdevname(rdev->bdev,b), mdname(mddev));
        return -EBUSY;
 }
@@ -4165,13 +4352,15 @@ static int set_array_info(mddev_t * mddev, mdu_array_info_t *info)
        else
                mddev->recovery_cp = 0;
        mddev->persistent    = ! info->not_persistent;
+       mddev->external      = 0;
 
        mddev->layout        = info->layout;
        mddev->chunk_size    = info->chunk_size;
 
        mddev->max_disks     = MD_SB_DISKS;
 
-       mddev->flags         = 0;
+       if (mddev->persistent)
+               mddev->flags         = 0;
        set_bit(MD_CHANGE_DEVS, &mddev->flags);
 
        mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
@@ -4213,7 +4402,7 @@ static int update_size(mddev_t *mddev, unsigned long size)
         */
        if (mddev->sync_thread)
                return -EBUSY;
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                sector_t avail;
                avail = rdev->size * 2;
 
@@ -4471,9 +4660,10 @@ static int md_ioctl(struct inode *inode, struct file *file,
         */
        /* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
         * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
-       if (!mddev->raid_disks && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
-                       && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
-                       && cmd != GET_BITMAP_FILE) {
+       if ((!mddev->raid_disks && !mddev->external)
+           && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
+           && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
+           && cmd != GET_BITMAP_FILE) {
                err = -ENODEV;
                goto abort_unlock;
        }
@@ -4757,7 +4947,7 @@ static void status_unused(struct seq_file *seq)
 
        seq_printf(seq, "unused devices: ");
 
-       ITERATE_RDEV_PENDING(rdev,tmp) {
+       rdev_for_each_list(rdev, tmp, pending_raid_disks) {
                char b[BDEVNAME_SIZE];
                i++;
                seq_printf(seq, "%s ",
@@ -4948,12 +5138,12 @@ static int md_seq_show(struct seq_file *seq, void *v)
                        if (mddev->ro==1)
                                seq_printf(seq, " (read-only)");
                        if (mddev->ro==2)
-                               seq_printf(seq, "(auto-read-only)");
+                               seq_printf(seq, " (auto-read-only)");
                        seq_printf(seq, " %s", mddev->pers->name);
                }
 
                size = 0;
-               ITERATE_RDEV(mddev,rdev,tmp2) {
+               rdev_for_each(rdev, tmp2, mddev) {
                        char b[BDEVNAME_SIZE];
                        seq_printf(seq, " %s[%d]",
                                bdevname(rdev->bdev,b), rdev->desc_nr);
@@ -4982,7 +5172,10 @@ static int md_seq_show(struct seq_file *seq, void *v)
                                           mddev->major_version,
                                           mddev->minor_version);
                        }
-               } else
+               } else if (mddev->external)
+                       seq_printf(seq, " super external:%s",
+                                  mddev->metadata_type);
+               else
                        seq_printf(seq, " super non-persistent");
 
                if (mddev->pers) {
@@ -5015,8 +5208,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
                                chunk_kb ? "KB" : "B");
                        if (bitmap->file) {
                                seq_printf(seq, ", file: ");
-                               seq_path(seq, bitmap->file->f_path.mnt,
-                                        bitmap->file->f_path.dentry," \t\n");
+                               seq_path(seq, &bitmap->file->f_path, " \t\n");
                        }
 
                        seq_printf(seq, "\n");
@@ -5106,7 +5298,7 @@ static int is_mddev_idle(mddev_t *mddev)
        long curr_events;
 
        idle = 1;
-       ITERATE_RDEV(mddev,rdev,tmp) {
+       rdev_for_each(rdev, tmp, mddev) {
                struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
                curr_events = disk_stat_read(disk, sectors[0]) + 
                                disk_stat_read(disk, sectors[1]) - 
@@ -5170,6 +5362,7 @@ void md_write_start(mddev_t *mddev, struct bio *bi)
                mddev->ro = 0;
                set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                md_wakeup_thread(mddev->thread);
+               md_wakeup_thread(mddev->sync_thread);
        }
        atomic_inc(&mddev->writes_pending);
        if (mddev->in_sync) {
@@ -5283,7 +5476,7 @@ void md_do_sync(mddev_t *mddev)
                        set_bit(MD_RECOVERY_INTR, &mddev->recovery);
                        goto skip;
                }
-               ITERATE_MDDEV(mddev2,tmp) {
+               for_each_mddev(mddev2, tmp) {
                        if (mddev2 == mddev)
                                continue;
                        if (mddev2->curr_resync && 
@@ -5333,7 +5526,7 @@ void md_do_sync(mddev_t *mddev)
                /* recovery follows the physical size of devices */
                max_sectors = mddev->size << 1;
                j = MaxSector;
-               ITERATE_RDEV(mddev,rdev,rtmp)
+               rdev_for_each(rdev, rtmp, mddev)
                        if (rdev->raid_disk >= 0 &&
                            !test_bit(Faulty, &rdev->flags) &&
                            !test_bit(In_sync, &rdev->flags) &&
@@ -5381,8 +5574,16 @@ void md_do_sync(mddev_t *mddev)
                sector_t sectors;
 
                skipped = 0;
+               if (j >= mddev->resync_max) {
+                       sysfs_notify(&mddev->kobj, NULL, "sync_completed");
+                       wait_event(mddev->recovery_wait,
+                                  mddev->resync_max > j
+                                  || kthread_should_stop());
+               }
+               if (kthread_should_stop())
+                       goto interrupted;
                sectors = mddev->pers->sync_request(mddev, j, &skipped,
-                                           currspeed < speed_min(mddev));
+                                                 currspeed < speed_min(mddev));
                if (sectors == 0) {
                        set_bit(MD_RECOVERY_ERR, &mddev->recovery);
                        goto out;
@@ -5424,15 +5625,9 @@ void md_do_sync(mddev_t *mddev)
                }
 
 
-               if (kthread_should_stop()) {
-                       /*
-                        * got a signal, exit.
-                        */
-                       printk(KERN_INFO 
-                               "md: md_do_sync() got signal ... exiting\n");
-                       set_bit(MD_RECOVERY_INTR, &mddev->recovery);
-                       goto out;
-               }
+               if (kthread_should_stop())
+                       goto interrupted;
+
 
                /*
                 * this loop exits only if either when we are slower than
@@ -5484,7 +5679,7 @@ void md_do_sync(mddev_t *mddev)
                } else {
                        if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
                                mddev->curr_resync = MaxSector;
-                       ITERATE_RDEV(mddev,rdev,rtmp)
+                       rdev_for_each(rdev, rtmp, mddev)
                                if (rdev->raid_disk >= 0 &&
                                    !test_bit(Faulty, &rdev->flags) &&
                                    !test_bit(In_sync, &rdev->flags) &&
@@ -5496,9 +5691,22 @@ void md_do_sync(mddev_t *mddev)
 
  skip:
        mddev->curr_resync = 0;
+       mddev->resync_max = MaxSector;
+       sysfs_notify(&mddev->kobj, NULL, "sync_completed");
        wake_up(&resync_wait);
        set_bit(MD_RECOVERY_DONE, &mddev->recovery);
        md_wakeup_thread(mddev->thread);
+       return;
+
+ interrupted:
+       /*
+        * got a signal, exit.
+        */
+       printk(KERN_INFO
+              "md: md_do_sync() got signal ... exiting\n");
+       set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+       goto out;
+
 }
 EXPORT_SYMBOL_GPL(md_do_sync);
 
@@ -5509,8 +5717,9 @@ static int remove_and_add_spares(mddev_t *mddev)
        struct list_head *rtmp;
        int spares = 0;
 
-       ITERATE_RDEV(mddev,rdev,rtmp)
+       rdev_for_each(rdev, rtmp, mddev)
                if (rdev->raid_disk >= 0 &&
+                   !mddev->external &&
                    (test_bit(Faulty, &rdev->flags) ||
                     ! test_bit(In_sync, &rdev->flags)) &&
                    atomic_read(&rdev->nr_pending)==0) {
@@ -5524,7 +5733,7 @@ static int remove_and_add_spares(mddev_t *mddev)
                }
 
        if (mddev->degraded) {
-               ITERATE_RDEV(mddev,rdev,rtmp)
+               rdev_for_each(rdev, rtmp, mddev)
                        if (rdev->raid_disk < 0
                            && !test_bit(Faulty, &rdev->flags)) {
                                rdev->recovery_offset = 0;
@@ -5589,7 +5798,7 @@ void md_check_recovery(mddev_t *mddev)
        }
 
        if ( ! (
-               mddev->flags ||
+               (mddev->flags && !mddev->external) ||
                test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
                test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
                (mddev->safemode == 1) ||
@@ -5605,7 +5814,8 @@ void md_check_recovery(mddev_t *mddev)
                if (mddev->safemode && !atomic_read(&mddev->writes_pending) &&
                    !mddev->in_sync && mddev->recovery_cp == MaxSector) {
                        mddev->in_sync = 1;
-                       set_bit(MD_CHANGE_CLEAN, &mddev->flags);
+                       if (mddev->persistent)
+                               set_bit(MD_CHANGE_CLEAN, &mddev->flags);
                }
                if (mddev->safemode == 1)
                        mddev->safemode = 0;
@@ -5637,7 +5847,7 @@ void md_check_recovery(mddev_t *mddev)
                         * information must be scrapped
                         */
                        if (!mddev->degraded)
-                               ITERATE_RDEV(mddev,rdev,rtmp)
+                               rdev_for_each(rdev, rtmp, mddev)
                                        rdev->saved_raid_disk = -1;
 
                        mddev->recovery = 0;
@@ -5714,7 +5924,7 @@ static int md_notify_reboot(struct notifier_block *this,
 
                printk(KERN_INFO "md: stopping all md devices.\n");
 
-               ITERATE_MDDEV(mddev,tmp)
+               for_each_mddev(mddev, tmp)
                        if (mddev_trylock(mddev)) {
                                do_md_stop (mddev, 1);
                                mddev_unlock(mddev);
@@ -5738,13 +5948,9 @@ static struct notifier_block md_notifier = {
 
 static void md_geninit(void)
 {
-       struct proc_dir_entry *p;
-
        dprintk("md: sizeof(mdp_super_t) = %d\n", (int)sizeof(mdp_super_t));
 
-       p = create_proc_entry("mdstat", S_IRUGO, NULL);
-       if (p)
-               p->proc_fops = &md_seq_fops;
+       proc_create("mdstat", S_IRUGO, NULL, &md_seq_fops);
 }
 
 static int __init md_init(void)
@@ -5823,6 +6029,7 @@ static void autostart_arrays(int part)
                        MD_BUG();
                        continue;
                }
+               set_bit(AutoDetected, &rdev->flags);
                list_add(&rdev->same_set, &pending_raid_disks);
                i_passed++;
        }
@@ -5848,7 +6055,7 @@ static __exit void md_exit(void)
        unregister_reboot_notifier(&md_notifier);
        unregister_sysctl_table(raid_table_header);
        remove_proc_entry("mdstat", NULL);
-       ITERATE_MDDEV(mddev,tmp) {
+       for_each_mddev(mddev, tmp) {
                struct gendisk *disk = mddev->gendisk;
                if (!disk)
                        continue;