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md.c

/*
   md.c : Multiple Devices driver for Linux
        Copyright (C) 1998, 1999, 2000 Ingo Molnar

     completely rewritten, based on the MD driver code from Marc Zyngier

   Changes:

   - RAID-1/RAID-5 extensions by Miguel de Icaza, Gadi Oxman, Ingo Molnar
   - RAID-6 extensions by H. Peter Anvin <hpa@zytor.com>
   - boot support for linear and striped mode by Harald Hoyer <HarryH@Royal.Net>
   - kerneld support by Boris Tobotras <boris@xtalk.msk.su>
   - kmod support by: Cyrus Durgin
   - RAID0 bugfixes: Mark Anthony Lisher <markal@iname.com>
   - Devfs support by Richard Gooch <rgooch@atnf.csiro.au>

   - lots of fixes and improvements to the RAID1/RAID5 and generic
     RAID code (such as request based resynchronization):

     Neil Brown <neilb@cse.unsw.edu.au>.

   - persistent bitmap code
     Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   You should have received a copy of the GNU General Public License
   (for example /usr/src/linux/COPYING); if not, write to the Free
   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <linux/kthread.h>
#include <linux/blkdev.h>
#include <linux/sysctl.h>
#include <linux/seq_file.h>
#include <linux/buffer_head.h> /* for invalidate_bdev */
#include <linux/poll.h>
#include <linux/ctype.h>
#include <linux/hdreg.h>
#include <linux/proc_fs.h>
#include <linux/random.h>
#include <linux/reboot.h>
#include <linux/file.h>
#include <linux/delay.h>
#include <linux/raid/md_p.h>
#include <linux/raid/md_u.h>
#include "md.h"
#include "bitmap.h"

#define DEBUG 0
#define dprintk(x...) ((void)(DEBUG && printk(x)))


#ifndef MODULE
static void autostart_arrays(int part);
#endif

static LIST_HEAD(pers_list);
static DEFINE_SPINLOCK(pers_lock);

static void md_print_devices(void);

static DECLARE_WAIT_QUEUE_HEAD(resync_wait);

#define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }

/*
 * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
 * is 1000 KB/sec, so the extra system load does not show up that much.
 * Increase it if you want to have more _guaranteed_ speed. Note that
 * the RAID driver will use the maximum available bandwidth if the IO
 * subsystem is idle. There is also an 'absolute maximum' reconstruction
 * speed limit - in case reconstruction slows down your system despite
 * idle IO detection.
 *
 * you can change it via /proc/sys/dev/raid/speed_limit_min and _max.
 * or /sys/block/mdX/md/sync_speed_{min,max}
 */

static int sysctl_speed_limit_min = 1000;
static int sysctl_speed_limit_max = 200000;
static inline int speed_min(mddev_t *mddev)
{
      return mddev->sync_speed_min ?
            mddev->sync_speed_min : sysctl_speed_limit_min;
}

static inline int speed_max(mddev_t *mddev)
{
      return mddev->sync_speed_max ?
            mddev->sync_speed_max : sysctl_speed_limit_max;
}

static struct ctl_table_header *raid_table_header;

static ctl_table raid_table[] = {
      {
            .ctl_name   = DEV_RAID_SPEED_LIMIT_MIN,
            .procname   = "speed_limit_min",
            .data       = &sysctl_speed_limit_min,
            .maxlen           = sizeof(int),
            .mode       = S_IRUGO|S_IWUSR,
            .proc_handler     = &proc_dointvec,
      },
      {
            .ctl_name   = DEV_RAID_SPEED_LIMIT_MAX,
            .procname   = "speed_limit_max",
            .data       = &sysctl_speed_limit_max,
            .maxlen           = sizeof(int),
            .mode       = S_IRUGO|S_IWUSR,
            .proc_handler     = &proc_dointvec,
      },
      { .ctl_name = 0 }
};

static ctl_table raid_dir_table[] = {
      {
            .ctl_name   = DEV_RAID,
            .procname   = "raid",
            .maxlen           = 0,
            .mode       = S_IRUGO|S_IXUGO,
            .child            = raid_table,
      },
      { .ctl_name = 0 }
};

static ctl_table raid_root_table[] = {
      {
            .ctl_name   = CTL_DEV,
            .procname   = "dev",
            .maxlen           = 0,
            .mode       = 0555,
            .child            = raid_dir_table,
      },
      { .ctl_name = 0 }
};

static struct block_device_operations md_fops;

static int start_readonly;

/*
 * We have a system wide 'event count' that is incremented
 * on any 'interesting' event, and readers of /proc/mdstat
 * can use 'poll' or 'select' to find out when the event
 * count increases.
 *
 * Events are:
 *  start array, stop array, error, add device, remove device,
 *  start build, activate spare
 */
static DECLARE_WAIT_QUEUE_HEAD(md_event_waiters);
static atomic_t md_event_count;
void md_new_event(mddev_t *mddev)
{
      atomic_inc(&md_event_count);
      wake_up(&md_event_waiters);
}
EXPORT_SYMBOL_GPL(md_new_event);

/* Alternate version that can be called from interrupts
 * when calling sysfs_notify isn't needed.
 */
static void md_new_event_inintr(mddev_t *mddev)
{
      atomic_inc(&md_event_count);
      wake_up(&md_event_waiters);
}

/*
 * Enables to iterate over all existing md arrays
 * all_mddevs_lock protects this list.
 */
static LIST_HEAD(all_mddevs);
static DEFINE_SPINLOCK(all_mddevs_lock);


/*
 * iterates through all used mddevs in the system.
 * We take care to grab the all_mddevs_lock whenever navigating
 * the list, and to always hold a refcount when unlocked.
 * Any code which breaks out of this loop while own
 * a reference to the current mddev and must mddev_put it.
 */
#define for_each_mddev(mddev,tmp)                           \
                                                      \
      for (({ spin_lock(&all_mddevs_lock);                        \
            tmp = all_mddevs.next;                          \
            mddev = NULL;});                          \
           ({ if (tmp != &all_mddevs)                             \
                  mddev_get(list_entry(tmp, mddev_t, all_mddevs));\
            spin_unlock(&all_mddevs_lock);                        \
            if (mddev) mddev_put(mddev);                    \
            mddev = list_entry(tmp, mddev_t, all_mddevs);         \
            tmp != &all_mddevs;});                          \
           ({ spin_lock(&all_mddevs_lock);                        \
            tmp = tmp->next;})                              \
            )


/* Rather than calling directly into the personality make_request function,
 * IO requests come here first so that we can check if the device is
 * being suspended pending a reconfiguration.
 * We hold a refcount over the call to ->make_request.  By the time that
 * call has finished, the bio has been linked into some internal structure
 * and so is visible to ->quiesce(), so we don't need the refcount any more.
 */
static int md_make_request(struct request_queue *q, struct bio *bio)
{
      mddev_t *mddev = q->queuedata;
      int rv;
      if (mddev == NULL || mddev->pers == NULL) {
            bio_io_error(bio);
            return 0;
      }
      rcu_read_lock();
      if (mddev->suspended) {
            DEFINE_WAIT(__wait);
            for (;;) {
                  prepare_to_wait(&mddev->sb_wait, &__wait,
                              TASK_UNINTERRUPTIBLE);
                  if (!mddev->suspended)
                        break;
                  rcu_read_unlock();
                  schedule();
                  rcu_read_lock();
            }
            finish_wait(&mddev->sb_wait, &__wait);
      }
      atomic_inc(&mddev->active_io);
      rcu_read_unlock();
      rv = mddev->pers->make_request(q, bio);
      if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
            wake_up(&mddev->sb_wait);

      return rv;
}

static void mddev_suspend(mddev_t *mddev)
{
      BUG_ON(mddev->suspended);
      mddev->suspended = 1;
      synchronize_rcu();
      wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
      mddev->pers->quiesce(mddev, 1);
      md_unregister_thread(mddev->thread);
      mddev->thread = NULL;
      /* we now know that no code is executing in the personality module,
       * except possibly the tail end of a ->bi_end_io function, but that
       * is certain to complete before the module has a chance to get
       * unloaded
       */
}

static void mddev_resume(mddev_t *mddev)
{
      mddev->suspended = 0;
      wake_up(&mddev->sb_wait);
      mddev->pers->quiesce(mddev, 0);
}


static inline mddev_t *mddev_get(mddev_t *mddev)
{
      atomic_inc(&mddev->active);
      return mddev;
}

static void mddev_delayed_delete(struct work_struct *ws);

static void mddev_put(mddev_t *mddev)
{
      if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
            return;
      if (!mddev->raid_disks && list_empty(&mddev->disks) &&
          !mddev->hold_active) {
            list_del(&mddev->all_mddevs);
            if (mddev->gendisk) {
                  /* we did a probe so need to clean up.
                   * Call schedule_work inside the spinlock
                   * so that flush_scheduled_work() after
                   * mddev_find will succeed in waiting for the
                   * work to be done.
                   */
                  INIT_WORK(&mddev->del_work, mddev_delayed_delete);
                  schedule_work(&mddev->del_work);
            } else
                  kfree(mddev);
      }
      spin_unlock(&all_mddevs_lock);
}

static mddev_t * mddev_find(dev_t unit)
{
      mddev_t *mddev, *new = NULL;

 retry:
      spin_lock(&all_mddevs_lock);

      if (unit) {
            list_for_each_entry(mddev, &all_mddevs, all_mddevs)
                  if (mddev->unit == unit) {
                        mddev_get(mddev);
                        spin_unlock(&all_mddevs_lock);
                        kfree(new);
                        return mddev;
                  }

            if (new) {
                  list_add(&new->all_mddevs, &all_mddevs);
                  spin_unlock(&all_mddevs_lock);
                  new->hold_active = UNTIL_IOCTL;
                  return new;
            }
      } else if (new) {
            /* find an unused unit number */
            static int next_minor = 512;
            int start = next_minor;
            int is_free = 0;
            int dev = 0;
            while (!is_free) {
                  dev = MKDEV(MD_MAJOR, next_minor);
                  next_minor++;
                  if (next_minor > MINORMASK)
                        next_minor = 0;
                  if (next_minor == start) {
                        /* Oh dear, all in use. */
                        spin_unlock(&all_mddevs_lock);
                        kfree(new);
                        return NULL;
                  }
                        
                  is_free = 1;
                  list_for_each_entry(mddev, &all_mddevs, all_mddevs)
                        if (mddev->unit == dev) {
                              is_free = 0;
                              break;
                        }
            }
            new->unit = dev;
            new->md_minor = MINOR(dev);
            new->hold_active = UNTIL_STOP;
            list_add(&new->all_mddevs, &all_mddevs);
            spin_unlock(&all_mddevs_lock);
            return new;
      }
      spin_unlock(&all_mddevs_lock);

      new = kzalloc(sizeof(*new), GFP_KERNEL);
      if (!new)
            return NULL;

      new->unit = unit;
      if (MAJOR(unit) == MD_MAJOR)
            new->md_minor = MINOR(unit);
      else
            new->md_minor = MINOR(unit) >> MdpMinorShift;

      mutex_init(&new->open_mutex);
      mutex_init(&new->reconfig_mutex);
      INIT_LIST_HEAD(&new->disks);
      INIT_LIST_HEAD(&new->all_mddevs);
      init_timer(&new->safemode_timer);
      atomic_set(&new->active, 1);
      atomic_set(&new->openers, 0);
      atomic_set(&new->active_io, 0);
      spin_lock_init(&new->write_lock);
      init_waitqueue_head(&new->sb_wait);
      init_waitqueue_head(&new->recovery_wait);
      new->reshape_position = MaxSector;
      new->resync_min = 0;
      new->resync_max = MaxSector;
      new->level = LEVEL_NONE;

      goto retry;
}

static inline int mddev_lock(mddev_t * mddev)
{
      return mutex_lock_interruptible(&mddev->reconfig_mutex);
}

static inline int mddev_is_locked(mddev_t *mddev)
{
      return mutex_is_locked(&mddev->reconfig_mutex);
}

static inline int mddev_trylock(mddev_t * mddev)
{
      return mutex_trylock(&mddev->reconfig_mutex);
}

static inline void mddev_unlock(mddev_t * mddev)
{
      mutex_unlock(&mddev->reconfig_mutex);

      md_wakeup_thread(mddev->thread);
}

static mdk_rdev_t * find_rdev_nr(mddev_t *mddev, int nr)
{
      mdk_rdev_t *rdev;

      list_for_each_entry(rdev, &mddev->disks, same_set)
            if (rdev->desc_nr == nr)
                  return rdev;

      return NULL;
}

static mdk_rdev_t * find_rdev(mddev_t * mddev, dev_t dev)
{
      mdk_rdev_t *rdev;

      list_for_each_entry(rdev, &mddev->disks, same_set)
            if (rdev->bdev->bd_dev == dev)
                  return rdev;

      return NULL;
}

static struct mdk_personality *find_pers(int level, char *clevel)
{
      struct mdk_personality *pers;
      list_for_each_entry(pers, &pers_list, list) {
            if (level != LEVEL_NONE && pers->level == level)
                  return pers;
            if (strcmp(pers->name, clevel)==0)
                  return pers;
      }
      return NULL;
}

/* return the offset of the super block in 512byte sectors */
static inline sector_t calc_dev_sboffset(struct block_device *bdev)
{
      sector_t num_sectors = bdev->bd_inode->i_size / 512;
      return MD_NEW_SIZE_SECTORS(num_sectors);
}

static int alloc_disk_sb(mdk_rdev_t * rdev)
{
      if (rdev->sb_page)
            MD_BUG();

      rdev->sb_page = alloc_page(GFP_KERNEL);
      if (!rdev->sb_page) {
            printk(KERN_ALERT "md: out of memory.\n");
            return -ENOMEM;
      }

      return 0;
}

static void free_disk_sb(mdk_rdev_t * rdev)
{
      if (rdev->sb_page) {
            put_page(rdev->sb_page);
            rdev->sb_loaded = 0;
            rdev->sb_page = NULL;
            rdev->sb_start = 0;
            rdev->sectors = 0;
      }
}


static void super_written(struct bio *bio, int error)
{
      mdk_rdev_t *rdev = bio->bi_private;
      mddev_t *mddev = rdev->mddev;

      if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags)) {
            printk("md: super_written gets error=%d, uptodate=%d\n",
                   error, test_bit(BIO_UPTODATE, &bio->bi_flags));
            WARN_ON(test_bit(BIO_UPTODATE, &bio->bi_flags));
            md_error(mddev, rdev);
      }

      if (atomic_dec_and_test(&mddev->pending_writes))
            wake_up(&mddev->sb_wait);
      bio_put(bio);
}

static void super_written_barrier(struct bio *bio, int error)
{
      struct bio *bio2 = bio->bi_private;
      mdk_rdev_t *rdev = bio2->bi_private;
      mddev_t *mddev = rdev->mddev;

      if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
          error == -EOPNOTSUPP) {
            unsigned long flags;
            /* barriers don't appear to be supported :-( */
            set_bit(BarriersNotsupp, &rdev->flags);
            mddev->barriers_work = 0;
            spin_lock_irqsave(&mddev->write_lock, flags);
            bio2->bi_next = mddev->biolist;
            mddev->biolist = bio2;
            spin_unlock_irqrestore(&mddev->write_lock, flags);
            wake_up(&mddev->sb_wait);
            bio_put(bio);
      } else {
            bio_put(bio2);
            bio->bi_private = rdev;
            super_written(bio, error);
      }
}

void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
               sector_t sector, int size, struct page *page)
{
      /* write first size bytes of page to sector of rdev
       * Increment mddev->pending_writes before returning
       * and decrement it on completion, waking up sb_wait
       * if zero is reached.
       * If an error occurred, call md_error
       *
       * As we might need to resubmit the request if BIO_RW_BARRIER
       * causes ENOTSUPP, we allocate a spare bio...
       */
      struct bio *bio = bio_alloc(GFP_NOIO, 1);
      int rw = (1<<BIO_RW) | (1<<BIO_RW_SYNCIO) | (1<<BIO_RW_UNPLUG);

      bio->bi_bdev = rdev->bdev;
      bio->bi_sector = sector;
      bio_add_page(bio, page, size, 0);
      bio->bi_private = rdev;
      bio->bi_end_io = super_written;
      bio->bi_rw = rw;

      atomic_inc(&mddev->pending_writes);
      if (!test_bit(BarriersNotsupp, &rdev->flags)) {
            struct bio *rbio;
            rw |= (1<<BIO_RW_BARRIER);
            rbio = bio_clone(bio, GFP_NOIO);
            rbio->bi_private = bio;
            rbio->bi_end_io = super_written_barrier;
            submit_bio(rw, rbio);
      } else
            submit_bio(rw, bio);
}

void md_super_wait(mddev_t *mddev)
{
      /* wait for all superblock writes that were scheduled to complete.
       * if any had to be retried (due to BARRIER problems), retry them
       */
      DEFINE_WAIT(wq);
      for(;;) {
            prepare_to_wait(&mddev->sb_wait, &wq, TASK_UNINTERRUPTIBLE);
            if (atomic_read(&mddev->pending_writes)==0)
                  break;
            while (mddev->biolist) {
                  struct bio *bio;
                  spin_lock_irq(&mddev->write_lock);
                  bio = mddev->biolist;
                  mddev->biolist = bio->bi_next ;
                  bio->bi_next = NULL;
                  spin_unlock_irq(&mddev->write_lock);
                  submit_bio(bio->bi_rw, bio);
            }
            schedule();
      }
      finish_wait(&mddev->sb_wait, &wq);
}

static void bi_complete(struct bio *bio, int error)
{
      complete((struct completion*)bio->bi_private);
}

int sync_page_io(struct block_device *bdev, sector_t sector, int size,
               struct page *page, int rw)
{
      struct bio *bio = bio_alloc(GFP_NOIO, 1);
      struct completion event;
      int ret;

      rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);

      bio->bi_bdev = bdev;
      bio->bi_sector = sector;
      bio_add_page(bio, page, size, 0);
      init_completion(&event);
      bio->bi_private = &event;
      bio->bi_end_io = bi_complete;
      submit_bio(rw, bio);
      wait_for_completion(&event);

      ret = test_bit(BIO_UPTODATE, &bio->bi_flags);
      bio_put(bio);
      return ret;
}
EXPORT_SYMBOL_GPL(sync_page_io);

static int read_disk_sb(mdk_rdev_t * rdev, int size)
{
      char b[BDEVNAME_SIZE];
      if (!rdev->sb_page) {
            MD_BUG();
            return -EINVAL;
      }
      if (rdev->sb_loaded)
            return 0;


      if (!sync_page_io(rdev->bdev, rdev->sb_start, size, rdev->sb_page, READ))
            goto fail;
      rdev->sb_loaded = 1;
      return 0;

fail:
      printk(KERN_WARNING "md: disabled device %s, could not read superblock.\n",
            bdevname(rdev->bdev,b));
      return -EINVAL;
}

static int uuid_equal(mdp_super_t *sb1, mdp_super_t *sb2)
{
      return      sb1->set_uuid0 == sb2->set_uuid0 &&
            sb1->set_uuid1 == sb2->set_uuid1 &&
            sb1->set_uuid2 == sb2->set_uuid2 &&
            sb1->set_uuid3 == sb2->set_uuid3;
}

static int sb_equal(mdp_super_t *sb1, mdp_super_t *sb2)
{
      int ret;
      mdp_super_t *tmp1, *tmp2;

      tmp1 = kmalloc(sizeof(*tmp1),GFP_KERNEL);
      tmp2 = kmalloc(sizeof(*tmp2),GFP_KERNEL);

      if (!tmp1 || !tmp2) {
            ret = 0;
            printk(KERN_INFO "md.c sb_equal(): failed to allocate memory!\n");
            goto abort;
      }

      *tmp1 = *sb1;
      *tmp2 = *sb2;

      /*
       * nr_disks is not constant
       */
      tmp1->nr_disks = 0;
      tmp2->nr_disks = 0;

      ret = (memcmp(tmp1, tmp2, MD_SB_GENERIC_CONSTANT_WORDS * 4) == 0);
abort:
      kfree(tmp1);
      kfree(tmp2);
      return ret;
}


static u32 md_csum_fold(u32 csum)
{
      csum = (csum & 0xffff) + (csum >> 16);
      return (csum & 0xffff) + (csum >> 16);
}

static unsigned int calc_sb_csum(mdp_super_t * sb)
{
      u64 newcsum = 0;
      u32 *sb32 = (u32*)sb;
      int i;
      unsigned int disk_csum, csum;

      disk_csum = sb->sb_csum;
      sb->sb_csum = 0;

      for (i = 0; i < MD_SB_BYTES/4 ; i++)
            newcsum += sb32[i];
      csum = (newcsum & 0xffffffff) + (newcsum>>32);


#ifdef CONFIG_ALPHA
      /* This used to use csum_partial, which was wrong for several
       * reasons including that different results are returned on
       * different architectures.  It isn't critical that we get exactly
       * the same return value as before (we always csum_fold before
       * testing, and that removes any differences).  However as we
       * know that csum_partial always returned a 16bit value on
       * alphas, do a fold to maximise conformity to previous behaviour.
       */
      sb->sb_csum = md_csum_fold(disk_csum);
#else
      sb->sb_csum = disk_csum;
#endif
      return csum;
}


/*
 * Handle superblock details.
 * We want to be able to handle multiple superblock formats
 * so we have a common interface to them all, and an array of
 * different handlers.
 * We rely on user-space to write the initial superblock, and support
 * reading and updating of superblocks.
 * Interface methods are:
 *   int load_super(mdk_rdev_t *dev, mdk_rdev_t *refdev, int minor_version)
 *      loads and validates a superblock on dev.
 *      if refdev != NULL, compare superblocks on both devices
 *    Return:
 *      0 - dev has a superblock that is compatible with refdev
 *      1 - dev has a superblock that is compatible and newer than refdev
 *          so dev should be used as the refdev in future
 *     -EINVAL superblock incompatible or invalid
 *     -othererror e.g. -EIO
 *
 *   int validate_super(mddev_t *mddev, mdk_rdev_t *dev)
 *      Verify that dev is acceptable into mddev.
 *       The first time, mddev->raid_disks will be 0, and data from
 *       dev should be merged in.  Subsequent calls check that dev
 *       is new enough.  Return 0 or -EINVAL
 *
 *   void sync_super(mddev_t *mddev, mdk_rdev_t *dev)
 *     Update the superblock for rdev with data in mddev
 *     This does not write to disc.
 *
 */

00728 struct super_type  {
      char            *name;
      struct module         *owner;
      int             (*load_super)(mdk_rdev_t *rdev, mdk_rdev_t *refdev,
                                int minor_version);
      int             (*validate_super)(mddev_t *mddev, mdk_rdev_t *rdev);
      void            (*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
      unsigned long long  (*rdev_size_change)(mdk_rdev_t *rdev,
                                    sector_t num_sectors);
};

/*
 * Check that the given mddev has no bitmap.
 *
 * This function is called from the run method of all personalities that do not
 * support bitmaps. It prints an error message and returns non-zero if mddev
 * has a bitmap. Otherwise, it returns 0.
 *
 */
int md_check_no_bitmap(mddev_t *mddev)
{
      if (!mddev->bitmap_file && !mddev->bitmap_offset)
            return 0;
      printk(KERN_ERR "%s: bitmaps are not supported for %s\n",
            mdname(mddev), mddev->pers->name);
      return 1;
}
EXPORT_SYMBOL(md_check_no_bitmap);

/*
 * load_super for 0.90.0 
 */
static int super_90_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
{
      char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
      mdp_super_t *sb;
      int ret;

      /*
       * Calculate the position of the superblock (512byte sectors),
       * it's at the end of the disk.
       *
       * It also happens to be a multiple of 4Kb.
       */
      rdev->sb_start = calc_dev_sboffset(rdev->bdev);

      ret = read_disk_sb(rdev, MD_SB_BYTES);
      if (ret) return ret;

      ret = -EINVAL;

      bdevname(rdev->bdev, b);
      sb = (mdp_super_t*)page_address(rdev->sb_page);

      if (sb->md_magic != MD_SB_MAGIC) {
            printk(KERN_ERR "md: invalid raid superblock magic on %s\n",
                   b);
            goto abort;
      }

      if (sb->major_version != 0 ||
          sb->minor_version < 90 ||
          sb->minor_version > 91) {
            printk(KERN_WARNING "Bad version number %d.%d on %s\n",
                  sb->major_version, sb->minor_version,
                  b);
            goto abort;
      }

      if (sb->raid_disks <= 0)
            goto abort;

      if (md_csum_fold(calc_sb_csum(sb)) != md_csum_fold(sb->sb_csum)) {
            printk(KERN_WARNING "md: invalid superblock checksum on %s\n",
                  b);
            goto abort;
      }

      rdev->preferred_minor = sb->md_minor;
      rdev->data_offset = 0;
      rdev->sb_size = MD_SB_BYTES;

      if (sb->level == LEVEL_MULTIPATH)
            rdev->desc_nr = -1;
      else
            rdev->desc_nr = sb->this_disk.number;

      if (!refdev) {
            ret = 1;
      } else {
            __u64 ev1, ev2;
            mdp_super_t *refsb = (mdp_super_t*)page_address(refdev->sb_page);
            if (!uuid_equal(refsb, sb)) {
                  printk(KERN_WARNING "md: %s has different UUID to %s\n",
                        b, bdevname(refdev->bdev,b2));
                  goto abort;
            }
            if (!sb_equal(refsb, sb)) {
                  printk(KERN_WARNING "md: %s has same UUID"
                         " but different superblock to %s\n",
                         b, bdevname(refdev->bdev, b2));
                  goto abort;
            }
            ev1 = md_event(sb);
            ev2 = md_event(refsb);
            if (ev1 > ev2)
                  ret = 1;
            else 
                  ret = 0;
      }
      rdev->sectors = rdev->sb_start;

      if (rdev->sectors < sb->size * 2 && sb->level > 1)
            /* "this cannot possibly happen" ... */
            ret = -EINVAL;

 abort:
      return ret;
}

/*
 * validate_super for 0.90.0
 */
static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
{
      mdp_disk_t *desc;
      mdp_super_t *sb = (mdp_super_t *)page_address(rdev->sb_page);
      __u64 ev1 = md_event(sb);

      rdev->raid_disk = -1;
      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->external = 0;
            mddev->chunk_sectors = sb->chunk_size >> 9;
            mddev->ctime = sb->ctime;
            mddev->utime = sb->utime;
            mddev->level = sb->level;
            mddev->clevel[0] = 0;
            mddev->layout = sb->layout;
            mddev->raid_disks = sb->raid_disks;
            mddev->dev_sectors = sb->size * 2;
            mddev->events = ev1;
            mddev->bitmap_offset = 0;
            mddev->default_bitmap_offset = MD_SB_BYTES >> 9;

            if (mddev->minor_version >= 91) {
                  mddev->reshape_position = sb->reshape_position;
                  mddev->delta_disks = sb->delta_disks;
                  mddev->new_level = sb->new_level;
                  mddev->new_layout = sb->new_layout;
                  mddev->new_chunk_sectors = sb->new_chunk >> 9;
            } else {
                  mddev->reshape_position = MaxSector;
                  mddev->delta_disks = 0;
                  mddev->new_level = mddev->level;
                  mddev->new_layout = mddev->layout;
                  mddev->new_chunk_sectors = mddev->chunk_sectors;
            }

            if (sb->state & (1<<MD_SB_CLEAN))
                  mddev->recovery_cp = MaxSector;
            else {
                  if (sb->events_hi == sb->cp_events_hi && 
                        sb->events_lo == sb->cp_events_lo) {
                        mddev->recovery_cp = sb->recovery_cp;
                  } else
                        mddev->recovery_cp = 0;
            }

            memcpy(mddev->uuid+0, &sb->set_uuid0, 4);
            memcpy(mddev->uuid+4, &sb->set_uuid1, 4);
            memcpy(mddev->uuid+8, &sb->set_uuid2, 4);
            memcpy(mddev->uuid+12,&sb->set_uuid3, 4);

            mddev->max_disks = MD_SB_DISKS;

            if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
                mddev->bitmap_file == NULL)
                  mddev->bitmap_offset = mddev->default_bitmap_offset;

      } else if (mddev->pers == NULL) {
            /* Insist on good event counter while assembling */
            ++ev1;
            if (ev1 < mddev->events) 
                  return -EINVAL;
      } else if (mddev->bitmap) {
            /* if adding to array with a bitmap, then we can accept an
             * older device ... but not too old.
             */
            if (ev1 < mddev->bitmap->events_cleared)
                  return 0;
      } else {
            if (ev1 < mddev->events)
                  /* just a hot-add of a new device, leave raid_disk at -1 */
                  return 0;
      }

      if (mddev->level != LEVEL_MULTIPATH) {
            desc = sb->disks + rdev->desc_nr;

            if (desc->state & (1<<MD_DISK_FAULTY))
                  set_bit(Faulty, &rdev->flags);
            else if (desc->state & (1<<MD_DISK_SYNC) /* &&
                      desc->raid_disk < mddev->raid_disks */) {
                  set_bit(In_sync, &rdev->flags);
                  rdev->raid_disk = desc->raid_disk;
            }
            if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
                  set_bit(WriteMostly, &rdev->flags);
      } else /* MULTIPATH are always insync */
            set_bit(In_sync, &rdev->flags);
      return 0;
}

/*
 * sync_super for 0.90.0
 */
static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
{
      mdp_super_t *sb;
      mdk_rdev_t *rdev2;
      int next_spare = mddev->raid_disks;


      /* make rdev->sb match mddev data..
       *
       * 1/ zero out disks
       * 2/ Add info for each disk, keeping track of highest desc_nr (next_spare);
       * 3/ any empty disks < next_spare become removed
       *
       * disks[0] gets initialised to REMOVED because
       * we cannot be sure from other fields if it has
       * been initialised or not.
       */
      int i;
      int active=0, working=0,failed=0,spare=0,nr_disks=0;

      rdev->sb_size = MD_SB_BYTES;

      sb = (mdp_super_t*)page_address(rdev->sb_page);

      memset(sb, 0, sizeof(*sb));

      sb->md_magic = MD_SB_MAGIC;
      sb->major_version = mddev->major_version;
      sb->patch_version = mddev->patch_version;
      sb->gvalid_words  = 0; /* ignored */
      memcpy(&sb->set_uuid0, mddev->uuid+0, 4);
      memcpy(&sb->set_uuid1, mddev->uuid+4, 4);
      memcpy(&sb->set_uuid2, mddev->uuid+8, 4);
      memcpy(&sb->set_uuid3, mddev->uuid+12,4);

      sb->ctime = mddev->ctime;
      sb->level = mddev->level;
      sb->size = mddev->dev_sectors / 2;
      sb->raid_disks = mddev->raid_disks;
      sb->md_minor = mddev->md_minor;
      sb->not_persistent = 0;
      sb->utime = mddev->utime;
      sb->state = 0;
      sb->events_hi = (mddev->events>>32);
      sb->events_lo = (u32)mddev->events;

      if (mddev->reshape_position == MaxSector)
            sb->minor_version = 90;
      else {
            sb->minor_version = 91;
            sb->reshape_position = mddev->reshape_position;
            sb->new_level = mddev->new_level;
            sb->delta_disks = mddev->delta_disks;
            sb->new_layout = mddev->new_layout;
            sb->new_chunk = mddev->new_chunk_sectors << 9;
      }
      mddev->minor_version = sb->minor_version;
      if (mddev->in_sync)
      {
            sb->recovery_cp = mddev->recovery_cp;
            sb->cp_events_hi = (mddev->events>>32);
            sb->cp_events_lo = (u32)mddev->events;
            if (mddev->recovery_cp == MaxSector)
                  sb->state = (1<< MD_SB_CLEAN);
      } else
            sb->recovery_cp = 0;

      sb->layout = mddev->layout;
      sb->chunk_size = mddev->chunk_sectors << 9;

      if (mddev->bitmap && mddev->bitmap_file == NULL)
            sb->state |= (1<<MD_SB_BITMAP_PRESENT);

      sb->disks[0].state = (1<<MD_DISK_REMOVED);
      list_for_each_entry(rdev2, &mddev->disks, same_set) {
            mdp_disk_t *d;
            int desc_nr;
            if (rdev2->raid_disk >= 0 && test_bit(In_sync, &rdev2->flags)
                && !test_bit(Faulty, &rdev2->flags))
                  desc_nr = rdev2->raid_disk;
            else
                  desc_nr = next_spare++;
            rdev2->desc_nr = desc_nr;
            d = &sb->disks[rdev2->desc_nr];
            nr_disks++;
            d->number = rdev2->desc_nr;
            d->major = MAJOR(rdev2->bdev->bd_dev);
            d->minor = MINOR(rdev2->bdev->bd_dev);
            if (rdev2->raid_disk >= 0 && test_bit(In_sync, &rdev2->flags)
                && !test_bit(Faulty, &rdev2->flags))
                  d->raid_disk = rdev2->raid_disk;
            else
                  d->raid_disk = rdev2->desc_nr; /* compatibility */
            if (test_bit(Faulty, &rdev2->flags))
                  d->state = (1<<MD_DISK_FAULTY);
            else if (test_bit(In_sync, &rdev2->flags)) {
                  d->state = (1<<MD_DISK_ACTIVE);
                  d->state |= (1<<MD_DISK_SYNC);
                  active++;
                  working++;
            } else {
                  d->state = 0;
                  spare++;
                  working++;
            }
            if (test_bit(WriteMostly, &rdev2->flags))
                  d->state |= (1<<MD_DISK_WRITEMOSTLY);
      }
      /* now set the "removed" and "faulty" bits on any missing devices */
      for (i=0 ; i < mddev->raid_disks ; i++) {
            mdp_disk_t *d = &sb->disks[i];
            if (d->state == 0 && d->number == 0) {
                  d->number = i;
                  d->raid_disk = i;
                  d->state = (1<<MD_DISK_REMOVED);
                  d->state |= (1<<MD_DISK_FAULTY);
                  failed++;
            }
      }
      sb->nr_disks = nr_disks;
      sb->active_disks = active;
      sb->working_disks = working;
      sb->failed_disks = failed;
      sb->spare_disks = spare;

      sb->this_disk = sb->disks[rdev->desc_nr];
      sb->sb_csum = calc_sb_csum(sb);
}

/*
 * rdev_size_change for 0.90.0
 */
static unsigned long long
super_90_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
{
      if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
            return 0; /* component must fit device */
      if (rdev->mddev->bitmap_offset)
            return 0; /* can't move bitmap */
      rdev->sb_start = calc_dev_sboffset(rdev->bdev);
      if (!num_sectors || num_sectors > rdev->sb_start)
            num_sectors = rdev->sb_start;
      md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
                   rdev->sb_page);
      md_super_wait(rdev->mddev);
      return num_sectors / 2; /* kB for sysfs */
}


/*
 * version 1 superblock
 */

static __le32 calc_sb_1_csum(struct mdp_superblock_1 * sb)
{
      __le32 disk_csum;
      u32 csum;
      unsigned long long newcsum;
      int size = 256 + le32_to_cpu(sb->max_dev)*2;
      __le32 *isuper = (__le32*)sb;
      int i;

      disk_csum = sb->sb_csum;
      sb->sb_csum = 0;
      newcsum = 0;
      for (i=0; size>=4; size -= 4 )
            newcsum += le32_to_cpu(*isuper++);

      if (size == 2)
            newcsum += le16_to_cpu(*(__le16*) isuper);

      csum = (newcsum & 0xffffffff) + (newcsum >> 32);
      sb->sb_csum = disk_csum;
      return cpu_to_le32(csum);
}

static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
{
      struct mdp_superblock_1 *sb;
      int ret;
      sector_t sb_start;
      char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
      int bmask;

      /*
       * Calculate the position of the superblock in 512byte sectors.
       * It is always aligned to a 4K boundary and
       * depeding on minor_version, it can be:
       * 0: At least 8K, but less than 12K, from end of device
       * 1: At start of device
       * 2: 4K from start of device.
       */
      switch(minor_version) {
      case 0:
            sb_start = rdev->bdev->bd_inode->i_size >> 9;
            sb_start -= 8*2;
            sb_start &= ~(sector_t)(4*2-1);
            break;
      case 1:
            sb_start = 0;
            break;
      case 2:
            sb_start = 8;
            break;
      default:
            return -EINVAL;
      }
      rdev->sb_start = sb_start;

      /* superblock is rarely larger than 1K, but it can be larger,
       * and it is safe to read 4k, so we do that
       */
      ret = read_disk_sb(rdev, 4096);
      if (ret) return ret;


      sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);

      if (sb->magic != cpu_to_le32(MD_SB_MAGIC) ||
          sb->major_version != cpu_to_le32(1) ||
          le32_to_cpu(sb->max_dev) > (4096-256)/2 ||
          le64_to_cpu(sb->super_offset) != rdev->sb_start ||
          (le32_to_cpu(sb->feature_map) & ~MD_FEATURE_ALL) != 0)
            return -EINVAL;

      if (calc_sb_1_csum(sb) != sb->sb_csum) {
            printk("md: invalid superblock checksum on %s\n",
                  bdevname(rdev->bdev,b));
            return -EINVAL;
      }
      if (le64_to_cpu(sb->data_size) < 10) {
            printk("md: data_size too small on %s\n",
                   bdevname(rdev->bdev,b));
            return -EINVAL;
      }

      rdev->preferred_minor = 0xffff;
      rdev->data_offset = le64_to_cpu(sb->data_offset);
      atomic_set(&rdev->corrected_errors, le32_to_cpu(sb->cnt_corrected_read));

      rdev->sb_size = le32_to_cpu(sb->max_dev) * 2 + 256;
      bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
      if (rdev->sb_size & bmask)
            rdev->sb_size = (rdev->sb_size | bmask) + 1;

      if (minor_version
          && rdev->data_offset < sb_start + (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) {
            ret = 1;
      } else {
            __u64 ev1, ev2;
            struct mdp_superblock_1 *refsb = 
                  (struct mdp_superblock_1*)page_address(refdev->sb_page);

            if (memcmp(sb->set_uuid, refsb->set_uuid, 16) != 0 ||
                sb->level != refsb->level ||
                sb->layout != refsb->layout ||
                sb->chunksize != refsb->chunksize) {
                  printk(KERN_WARNING "md: %s has strangely different"
                        " superblock to %s\n",
                        bdevname(rdev->bdev,b),
                        bdevname(refdev->bdev,b2));
                  return -EINVAL;
            }
            ev1 = le64_to_cpu(sb->events);
            ev2 = le64_to_cpu(refsb->events);

            if (ev1 > ev2)
                  ret = 1;
            else
                  ret = 0;
      }
      if (minor_version)
            rdev->sectors = (rdev->bdev->bd_inode->i_size >> 9) -
                  le64_to_cpu(sb->data_offset);
      else
            rdev->sectors = rdev->sb_start;
      if (rdev->sectors < le64_to_cpu(sb->data_size))
            return -EINVAL;
      rdev->sectors = le64_to_cpu(sb->data_size);
      if (le64_to_cpu(sb->size) > rdev->sectors)
            return -EINVAL;
      return ret;
}

static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
{
      struct mdp_superblock_1 *sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
      __u64 ev1 = le64_to_cpu(sb->events);

      rdev->raid_disk = -1;
      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->external = 0;
            mddev->chunk_sectors = le32_to_cpu(sb->chunksize);
            mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
            mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
            mddev->level = le32_to_cpu(sb->level);
            mddev->clevel[0] = 0;
            mddev->layout = le32_to_cpu(sb->layout);
            mddev->raid_disks = le32_to_cpu(sb->raid_disks);
            mddev->dev_sectors = le64_to_cpu(sb->size);
            mddev->events = ev1;
            mddev->bitmap_offset = 0;
            mddev->default_bitmap_offset = 1024 >> 9;
            
            mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
            memcpy(mddev->uuid, sb->set_uuid, 16);

            mddev->max_disks =  (4096-256)/2;

            if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
                mddev->bitmap_file == NULL )
                  mddev->bitmap_offset = (__s32)le32_to_cpu(sb->bitmap_offset);

            if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
                  mddev->reshape_position = le64_to_cpu(sb->reshape_position);
                  mddev->delta_disks = le32_to_cpu(sb->delta_disks);
                  mddev->new_level = le32_to_cpu(sb->new_level);
                  mddev->new_layout = le32_to_cpu(sb->new_layout);
                  mddev->new_chunk_sectors = le32_to_cpu(sb->new_chunk);
            } else {
                  mddev->reshape_position = MaxSector;
                  mddev->delta_disks = 0;
                  mddev->new_level = mddev->level;
                  mddev->new_layout = mddev->layout;
                  mddev->new_chunk_sectors = mddev->chunk_sectors;
            }

      } else if (mddev->pers == NULL) {
            /* Insist of good event counter while assembling */
            ++ev1;
            if (ev1 < mddev->events)
                  return -EINVAL;
      } else if (mddev->bitmap) {
            /* If adding to array with a bitmap, then we can accept an
             * older device, but not too old.
             */
            if (ev1 < mddev->bitmap->events_cleared)
                  return 0;
      } else {
            if (ev1 < mddev->events)
                  /* just a hot-add of a new device, leave raid_disk at -1 */
                  return 0;
      }
      if (mddev->level != LEVEL_MULTIPATH) {
            int role;
            if (rdev->desc_nr < 0 ||
                rdev->desc_nr >= le32_to_cpu(sb->max_dev)) {
                  role = 0xffff;
                  rdev->desc_nr = -1;
            } else
                  role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
            switch(role) {
            case 0xffff: /* spare */
                  break;
            case 0xfffe: /* faulty */
                  set_bit(Faulty, &rdev->flags);
                  break;
            default:
                  if ((le32_to_cpu(sb->feature_map) &
                       MD_FEATURE_RECOVERY_OFFSET))
                        rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
                  else
                        set_bit(In_sync, &rdev->flags);
                  rdev->raid_disk = role;
                  break;
            }
            if (sb->devflags & WriteMostly1)
                  set_bit(WriteMostly, &rdev->flags);
      } else /* MULTIPATH are always insync */
            set_bit(In_sync, &rdev->flags);

      return 0;
}

static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
{
      struct mdp_superblock_1 *sb;
      mdk_rdev_t *rdev2;
      int max_dev, i;
      /* make rdev->sb match mddev and rdev data. */

      sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);

      sb->feature_map = 0;
      sb->pad0 = 0;
      sb->recovery_offset = cpu_to_le64(0);
      memset(sb->pad1, 0, sizeof(sb->pad1));
      memset(sb->pad2, 0, sizeof(sb->pad2));
      memset(sb->pad3, 0, sizeof(sb->pad3));

      sb->utime = cpu_to_le64((__u64)mddev->utime);
      sb->events = cpu_to_le64(mddev->events);
      if (mddev->in_sync)
            sb->resync_offset = cpu_to_le64(mddev->recovery_cp);
      else
            sb->resync_offset = cpu_to_le64(0);

      sb->cnt_corrected_read = cpu_to_le32(atomic_read(&rdev->corrected_errors));

      sb->raid_disks = cpu_to_le32(mddev->raid_disks);
      sb->size = cpu_to_le64(mddev->dev_sectors);
      sb->chunksize = cpu_to_le32(mddev->chunk_sectors);
      sb->level = cpu_to_le32(mddev->level);
      sb->layout = cpu_to_le32(mddev->layout);

      if (mddev->bitmap && mddev->bitmap_file == NULL) {
            sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);
            sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
      }

      if (rdev->raid_disk >= 0 &&
          !test_bit(In_sync, &rdev->flags)) {
            if (mddev->curr_resync_completed > rdev->recovery_offset)
                  rdev->recovery_offset = mddev->curr_resync_completed;
            if (rdev->recovery_offset > 0) {
                  sb->feature_map |=
                        cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
                  sb->recovery_offset =
                        cpu_to_le64(rdev->recovery_offset);
            }
      }

      if (mddev->reshape_position != MaxSector) {
            sb->feature_map |= cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
            sb->reshape_position = cpu_to_le64(mddev->reshape_position);
            sb->new_layout = cpu_to_le32(mddev->new_layout);
            sb->delta_disks = cpu_to_le32(mddev->delta_disks);
            sb->new_level = cpu_to_le32(mddev->new_level);
            sb->new_chunk = cpu_to_le32(mddev->new_chunk_sectors);
      }

      max_dev = 0;
      list_for_each_entry(rdev2, &mddev->disks, same_set)
            if (rdev2->desc_nr+1 > max_dev)
                  max_dev = rdev2->desc_nr+1;

      if (max_dev > le32_to_cpu(sb->max_dev)) {
            int bmask;
            sb->max_dev = cpu_to_le32(max_dev);
            rdev->sb_size = max_dev * 2 + 256;
            bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
            if (rdev->sb_size & bmask)
                  rdev->sb_size = (rdev->sb_size | bmask) + 1;
      }
      for (i=0; i<max_dev;i++)
            sb->dev_roles[i] = cpu_to_le16(0xfffe);
      
      list_for_each_entry(rdev2, &mddev->disks, same_set) {
            i = rdev2->desc_nr;
            if (test_bit(Faulty, &rdev2->flags))
                  sb->dev_roles[i] = cpu_to_le16(0xfffe);
            else if (test_bit(In_sync, &rdev2->flags))
                  sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
            else if (rdev2->raid_disk >= 0 && rdev2->recovery_offset > 0)
                  sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
            else
                  sb->dev_roles[i] = cpu_to_le16(0xffff);
      }

      sb->sb_csum = calc_sb_1_csum(sb);
}

static unsigned long long
super_1_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
{
      struct mdp_superblock_1 *sb;
      sector_t max_sectors;
      if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
            return 0; /* component must fit device */
      if (rdev->sb_start < rdev->data_offset) {
            /* minor versions 1 and 2; superblock before data */
            max_sectors = rdev->bdev->bd_inode->i_size >> 9;
            max_sectors -= rdev->data_offset;
            if (!num_sectors || num_sectors > max_sectors)
                  num_sectors = max_sectors;
      } else if (rdev->mddev->bitmap_offset) {
            /* minor version 0 with bitmap we can't move */
            return 0;
      } else {
            /* minor version 0; superblock after data */
            sector_t sb_start;
            sb_start = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
            sb_start &= ~(sector_t)(4*2 - 1);
            max_sectors = rdev->sectors + sb_start - rdev->sb_start;
            if (!num_sectors || num_sectors > max_sectors)
                  num_sectors = max_sectors;
            rdev->sb_start = sb_start;
      }
      sb = (struct mdp_superblock_1 *) page_address(rdev->sb_page);
      sb->data_size = cpu_to_le64(num_sectors);
      sb->super_offset = rdev->sb_start;
      sb->sb_csum = calc_sb_1_csum(sb);
      md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
                   rdev->sb_page);
      md_super_wait(rdev->mddev);
      return num_sectors / 2; /* kB for sysfs */
}

static struct super_type super_types[] = {
      [0] = {
            .name = "0.90.0",
            .owner      = THIS_MODULE,
            .load_super     = super_90_load,
            .validate_super       = super_90_validate,
            .sync_super     = super_90_sync,
            .rdev_size_change   = super_90_rdev_size_change,
      },
      [1] = {
            .name = "md-1",
            .owner      = THIS_MODULE,
            .load_super     = super_1_load,
            .validate_super       = super_1_validate,
            .sync_super     = super_1_sync,
            .rdev_size_change   = super_1_rdev_size_change,
      },
};

static int match_mddev_units(mddev_t *mddev1, mddev_t *mddev2)
{
      mdk_rdev_t *rdev, *rdev2;

      rcu_read_lock();
      rdev_for_each_rcu(rdev, mddev1)
            rdev_for_each_rcu(rdev2, mddev2)
                  if (rdev->bdev->bd_contains ==
                      rdev2->bdev->bd_contains) {
                        rcu_read_unlock();
                        return 1;
                  }
      rcu_read_unlock();
      return 0;
}

static LIST_HEAD(pending_raid_disks);

/*
 * Try to register data integrity profile for an mddev
 *
 * This is called when an array is started and after a disk has been kicked
 * from the array. It only succeeds if all working and active component devices
 * are integrity capable with matching profiles.
 */
int md_integrity_register(mddev_t *mddev)
{
      mdk_rdev_t *rdev, *reference = NULL;

      if (list_empty(&mddev->disks))
            return 0; /* nothing to do */
      if (blk_get_integrity(mddev->gendisk))
            return 0; /* already registered */
      list_for_each_entry(rdev, &mddev->disks, same_set) {
            /* skip spares and non-functional disks */
            if (test_bit(Faulty, &rdev->flags))
                  continue;
            if (rdev->raid_disk < 0)
                  continue;
            /*
             * If at least one rdev is not integrity capable, we can not
             * enable data integrity for the md device.
             */
            if (!bdev_get_integrity(rdev->bdev))
                  return -EINVAL;
            if (!reference) {
                  /* Use the first rdev as the reference */
                  reference = rdev;
                  continue;
            }
            /* does this rdev's profile match the reference profile? */
            if (blk_integrity_compare(reference->bdev->bd_disk,
                        rdev->bdev->bd_disk) < 0)
                  return -EINVAL;
      }
      /*
       * All component devices are integrity capable and have matching
       * profiles, register the common profile for the md device.
       */
      if (blk_integrity_register(mddev->gendisk,
                  bdev_get_integrity(reference->bdev)) != 0) {
            printk(KERN_ERR "md: failed to register integrity for %s\n",
                  mdname(mddev));
            return -EINVAL;
      }
      printk(KERN_NOTICE "md: data integrity on %s enabled\n",
            mdname(mddev));
      return 0;
}
EXPORT_SYMBOL(md_integrity_register);

/* Disable data integrity if non-capable/non-matching disk is being added */
void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
{
      struct blk_integrity *bi_rdev = bdev_get_integrity(rdev->bdev);
      struct blk_integrity *bi_mddev = blk_get_integrity(mddev->gendisk);

      if (!bi_mddev) /* nothing to do */
            return;
      if (rdev->raid_disk < 0) /* skip spares */
            return;
      if (bi_rdev && blk_integrity_compare(mddev->gendisk,
                                   rdev->bdev->bd_disk) >= 0)
            return;
      printk(KERN_NOTICE "disabling data integrity on %s\n", mdname(mddev));
      blk_integrity_unregister(mddev->gendisk);
}
EXPORT_SYMBOL(md_integrity_add_rdev);

static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
{
      char b[BDEVNAME_SIZE];
      struct kobject *ko;
      char *s;
      int err;

      if (rdev->mddev) {
            MD_BUG();
            return -EINVAL;
      }

      /* prevent duplicates */
      if (find_rdev(mddev, rdev->bdev->bd_dev))
            return -EEXIST;

      /* make sure rdev->sectors exceeds mddev->dev_sectors */
      if (rdev->sectors && (mddev->dev_sectors == 0 ||
                  rdev->sectors < mddev->dev_sectors)) {
            if (mddev->pers) {
                  /* Cannot change size, so fail
                   * If mddev->level <= 0, then we don't care
                   * about aligning sizes (e.g. linear)
                   */
                  if (mddev->level > 0)
                        return -ENOSPC;
            } else
                  mddev->dev_sectors = rdev->sectors;
      }

      /* Verify rdev->desc_nr is unique.
       * If it is -1, assign a free number, else
       * check number is not in use
       */
      if (rdev->desc_nr < 0) {
            int choice = 0;
            if (mddev->pers) choice = mddev->raid_disks;
            while (find_rdev_nr(mddev, choice))
                  choice++;
            rdev->desc_nr = choice;
      } else {
            if (find_rdev_nr(mddev, rdev->desc_nr))
                  return -EBUSY;
      }
      if (mddev->max_disks && rdev->desc_nr >= mddev->max_disks) {
            printk(KERN_WARNING "md: %s: array is limited to %d devices\n",
                   mdname(mddev), mddev->max_disks);
            return -EBUSY;
      }
      bdevname(rdev->bdev,b);
      while ( (s=strchr(b, '/')) != NULL)
            *s = '!';

      rdev->mddev = mddev;
      printk(KERN_INFO "md: bind<%s>\n", b);

      if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
            goto fail;

      ko = &part_to_dev(rdev->bdev->bd_part)->kobj;
      if ((err = sysfs_create_link(&rdev->kobj, ko, "block"))) {
            kobject_del(&rdev->kobj);
            goto fail;
      }
      rdev->sysfs_state = sysfs_get_dirent(rdev->kobj.sd, "state");

      list_add_rcu(&rdev->same_set, &mddev->disks);
      bd_claim_by_disk(rdev->bdev, rdev->bdev->bd_holder, mddev->gendisk);

      /* May as well allow recovery to be retried once */
      mddev->recovery_disabled = 0;

      return 0;

 fail:
      printk(KERN_WARNING "md: failed to register dev-%s for %s\n",
             b, mdname(mddev));
      return err;
}

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)
{
      char b[BDEVNAME_SIZE];
      if (!rdev->mddev) {
            MD_BUG();
            return;
      }
      bd_release_from_disk(rdev->bdev, rdev->mddev->gendisk);
      list_del_rcu(&rdev->same_set);
      printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
      rdev->mddev = NULL;
      sysfs_remove_link(&rdev->kobj, "block");
      sysfs_put(rdev->sysfs_state);
      rdev->sysfs_state = NULL;
      /* We need to delay this, otherwise we can deadlock when
       * writing to 'remove' to "dev/state".  We also need
       * to delay it due to rcu usage.
       */
      synchronize_rcu();
      INIT_WORK(&rdev->del_work, md_delayed_delete);
      kobject_get(&rdev->kobj);
      schedule_work(&rdev->del_work);
}

/*
 * prevent the device from being mounted, repartitioned or
 * 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, int shared)
{
      int err = 0;
      struct block_device *bdev;
      char b[BDEVNAME_SIZE];

      bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
      if (IS_ERR(bdev)) {
            printk(KERN_ERR "md: could not open %s.\n",
                  __bdevname(dev, b));
            return PTR_ERR(bdev);
      }
      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, FMODE_READ|FMODE_WRITE);
            return err;
      }
      if (!shared)
            set_bit(AllReserved, &rdev->flags);
      rdev->bdev = bdev;
      return err;
}

static void unlock_rdev(mdk_rdev_t *rdev)
{
      struct block_device *bdev = rdev->bdev;
      rdev->bdev = NULL;
      if (!bdev)
            MD_BUG();
      bd_release(bdev);
      blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
}

void md_autodetect_dev(dev_t dev);

static void export_rdev(mdk_rdev_t * rdev)
{
      char b[BDEVNAME_SIZE];
      printk(KERN_INFO "md: export_rdev(%s)\n",
            bdevname(rdev->bdev,b));
      if (rdev->mddev)
            MD_BUG();
      free_disk_sb(rdev);
#ifndef MODULE
      if (test_bit(AutoDetected, &rdev->flags))
            md_autodetect_dev(rdev->bdev->bd_dev);
#endif
      unlock_rdev(rdev);
      kobject_put(&rdev->kobj);
}

static void kick_rdev_from_array(mdk_rdev_t * rdev)
{
      unbind_rdev_from_array(rdev);
      export_rdev(rdev);
}

static void export_array(mddev_t *mddev)
{
      mdk_rdev_t *rdev, *tmp;

      rdev_for_each(rdev, tmp, mddev) {
            if (!rdev->mddev) {
                  MD_BUG();
                  continue;
            }
            kick_rdev_from_array(rdev);
      }
      if (!list_empty(&mddev->disks))
            MD_BUG();
      mddev->raid_disks = 0;
      mddev->major_version = 0;
}

static void print_desc(mdp_disk_t *desc)
{
      printk(" DISK<N:%d,(%d,%d),R:%d,S:%d>\n", desc->number,
            desc->major,desc->minor,desc->raid_disk,desc->state);
}

static void print_sb_90(mdp_super_t *sb)
{
      int i;

      printk(KERN_INFO 
            "md:  SB: (V:%d.%d.%d) ID:<%08x.%08x.%08x.%08x> CT:%08x\n",
            sb->major_version, sb->minor_version, sb->patch_version,
            sb->set_uuid0, sb->set_uuid1, sb->set_uuid2, sb->set_uuid3,
            sb->ctime);
      printk(KERN_INFO "md:     L%d S%08d ND:%d RD:%d md%d LO:%d CS:%d\n",
            sb->level, sb->size, sb->nr_disks, sb->raid_disks,
            sb->md_minor, sb->layout, sb->chunk_size);
      printk(KERN_INFO "md:     UT:%08x ST:%d AD:%d WD:%d"
            " FD:%d SD:%d CSUM:%08x E:%08lx\n",
            sb->utime, sb->state, sb->active_disks, sb->working_disks,
            sb->failed_disks, sb->spare_disks,
            sb->sb_csum, (unsigned long)sb->events_lo);

      printk(KERN_INFO);
      for (i = 0; i < MD_SB_DISKS; i++) {
            mdp_disk_t *desc;

            desc = sb->disks + i;
            if (desc->number || desc->major || desc->minor ||
                desc->raid_disk || (desc->state && (desc->state != 4))) {
                  printk("     D %2d: ", i);
                  print_desc(desc);
            }
      }
      printk(KERN_INFO "md:     THIS: ");
      print_desc(&sb->this_disk);
}

static void print_sb_1(struct mdp_superblock_1 *sb)
{
      __u8 *uuid;

      uuid = sb->set_uuid;
      printk(KERN_INFO
             "md:  SB: (V:%u) (F:0x%08x) Array-ID:<%02x%02x%02x%02x"
             ":%02x%02x:%02x%02x:%02x%02x:%02x%02x%02x%02x%02x%02x>\n"
             "md:    Name: \"%s\" CT:%llu\n",
            le32_to_cpu(sb->major_version),
            le32_to_cpu(sb->feature_map),
            uuid[0], uuid[1], uuid[2], uuid[3],
            uuid[4], uuid[5], uuid[6], uuid[7],
            uuid[8], uuid[9], uuid[10], uuid[11],
            uuid[12], uuid[13], uuid[14], uuid[15],
            sb->set_name,
            (unsigned long long)le64_to_cpu(sb->ctime)
                   & MD_SUPERBLOCK_1_TIME_SEC_MASK);

      uuid = sb->device_uuid;
      printk(KERN_INFO
             "md:       L%u SZ%llu RD:%u LO:%u CS:%u DO:%llu DS:%llu SO:%llu"
                  " RO:%llu\n"
             "md:     Dev:%08x UUID: %02x%02x%02x%02x:%02x%02x:%02x%02x:%02x%02x"
                      ":%02x%02x%02x%02x%02x%02x\n"
             "md:       (F:0x%08x) UT:%llu Events:%llu ResyncOffset:%llu CSUM:0x%08x\n"
             "md:         (MaxDev:%u) \n",
            le32_to_cpu(sb->level),
            (unsigned long long)le64_to_cpu(sb->size),
            le32_to_cpu(sb->raid_disks),
            le32_to_cpu(sb->layout),
            le32_to_cpu(sb->chunksize),
            (unsigned long long)le64_to_cpu(sb->data_offset),
            (unsigned long long)le64_to_cpu(sb->data_size),
            (unsigned long long)le64_to_cpu(sb->super_offset),
            (unsigned long long)le64_to_cpu(sb->recovery_offset),
            le32_to_cpu(sb->dev_number),
            uuid[0], uuid[1], uuid[2], uuid[3],
            uuid[4], uuid[5], uuid[6], uuid[7],
            uuid[8], uuid[9], uuid[10], uuid[11],
            uuid[12], uuid[13], uuid[14], uuid[15],
            sb->devflags,
            (unsigned long long)le64_to_cpu(sb->utime) & MD_SUPERBLOCK_1_TIME_SEC_MASK,
            (unsigned long long)le64_to_cpu(sb->events),
            (unsigned long long)le64_to_cpu(sb->resync_offset),
            le32_to_cpu(sb->sb_csum),
            le32_to_cpu(sb->max_dev)
            );
}

static void print_rdev(mdk_rdev_t *rdev, int major_version)
{
      char b[BDEVNAME_SIZE];
      printk(KERN_INFO "md: rdev %s, Sect:%08llu F:%d S:%d DN:%u\n",
            bdevname(rdev->bdev, b), (unsigned long long)rdev->sectors,
              test_bit(Faulty, &rdev->flags), test_bit(In_sync, &rdev->flags),
              rdev->desc_nr);
      if (rdev->sb_loaded) {
            printk(KERN_INFO "md: rdev superblock (MJ:%d):\n", major_version);
            switch (major_version) {
            case 0:
                  print_sb_90((mdp_super_t*)page_address(rdev->sb_page));
                  break;
            case 1:
                  print_sb_1((struct mdp_superblock_1 *)page_address(rdev->sb_page));
                  break;
            }
      } else
            printk(KERN_INFO "md: no rdev superblock!\n");
}

static void md_print_devices(void)
{
      struct list_head *tmp;
      mdk_rdev_t *rdev;
      mddev_t *mddev;
      char b[BDEVNAME_SIZE];

      printk("\n");
      printk("md: **********************************\n");
      printk("md: * <COMPLETE RAID STATE PRINTOUT> *\n");
      printk("md: **********************************\n");
      for_each_mddev(mddev, tmp) {

            if (mddev->bitmap)
                  bitmap_print_sb(mddev->bitmap);
            else
                  printk("%s: ", mdname(mddev));
            list_for_each_entry(rdev, &mddev->disks, same_set)
                  printk("<%s>", bdevname(rdev->bdev,b));
            printk("\n");

            list_for_each_entry(rdev, &mddev->disks, same_set)
                  print_rdev(rdev, mddev->major_version);
      }
      printk("md: **********************************\n");
      printk("\n");
}


static void sync_sbs(mddev_t * mddev, int nospares)
{
      /* Update each superblock (in-memory image), but
       * if we are allowed to, skip spares which already
       * have the right event counter, or have one earlier
       * (which would mean they aren't being marked as dirty
       * with the rest of the array)
       */
      mdk_rdev_t *rdev;

      list_for_each_entry(rdev, &mddev->disks, same_set) {
            if (rdev->sb_events == mddev->events ||
                (nospares &&
                 rdev->raid_disk < 0 &&
                 (rdev->sb_events&1)==0 &&
                 rdev->sb_events+1 == mddev->events)) {
                  /* Don't update this superblock */
                  rdev->sb_loaded = 2;
            } else {
                  super_types[mddev->major_version].
                        sync_super(mddev, rdev);
                  rdev->sb_loaded = 1;
            }
      }
}

static void md_update_sb(mddev_t * mddev, int force_change)
{
      mdk_rdev_t *rdev;
      int sync_req;
      int nospares = 0;

      mddev->utime = get_seconds();
      if (mddev->external)
            return;
repeat:
      spin_lock_irq(&mddev->write_lock);

      set_bit(MD_CHANGE_PENDING, &mddev->flags);
      if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))
            force_change = 1;
      if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))
            /* just a clean<-> dirty transition, possibly leave spares alone,
             * though if events isn't the right even/odd, we will have to do
             * spares after all
             */
            nospares = 1;
      if (force_change)
            nospares = 0;
      if (mddev->degraded)
            /* If the array is degraded, then skipping spares is both
             * dangerous and fairly pointless.
             * Dangerous because a device that was removed from the array
             * might have a event_count that still looks up-to-date,
             * so it can be re-added without a resync.
             * Pointless because if there are any spares to skip,
             * then a recovery will happen and soon that array won't
             * be degraded any more and the spare can go back to sleep then.
             */
            nospares = 0;

      sync_req = mddev->in_sync;

      /* If this is just a dirty<->clean transition, and the array is clean
       * and 'events' is odd, we can roll back to the previous clean state */
      if (nospares
          && (mddev->in_sync && mddev->recovery_cp == MaxSector)
          && (mddev->events & 1)
          && mddev->events != 1)
            mddev->events--;
      else {
            /* otherwise we have to go forward and ... */
            mddev->events ++;
            if (!mddev->in_sync || mddev->recovery_cp != MaxSector) { /* not clean */
                  /* .. if the array isn't clean, an 'even' event must also go
                   * to spares. */
                  if ((mddev->events&1)==0)
                        nospares = 0;
            } else {
                  /* otherwise an 'odd' event must go to spares */
                  if ((mddev->events&1))
                        nospares = 0;
            }
      }

      if (!mddev->events) {
            /*
             * oops, this 64-bit counter should never wrap.
             * Either we are in around ~1 trillion A.C., assuming
             * 1 reboot per second, or we have a bug:
             */
            MD_BUG();
            mddev->events --;
      }

      /*
       * do not write anything to disk if using
       * nonpersistent superblocks
       */
      if (!mddev->persistent) {
            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 
            "md: updating %s RAID superblock on device (in sync %d)\n",
            mdname(mddev),mddev->in_sync);

      bitmap_update_sb(mddev->bitmap);
      list_for_each_entry(rdev, &mddev->disks, same_set) {
            char b[BDEVNAME_SIZE];
            dprintk(KERN_INFO "md: ");
            if (rdev->sb_loaded != 1)
                  continue; /* no noise on spare devices */
            if (test_bit(Faulty, &rdev->flags))
                  dprintk("(skipping faulty ");

            dprintk("%s ", bdevname(rdev->bdev,b));
            if (!test_bit(Faulty, &rdev->flags)) {
                  md_super_write(mddev,rdev,
                               rdev->sb_start, rdev->sb_size,
                               rdev->sb_page);
                  dprintk(KERN_INFO "(write) %s's sb offset: %llu\n",
                        bdevname(rdev->bdev,b),
                        (unsigned long long)rdev->sb_start);
                  rdev->sb_events = mddev->events;

            } else
                  dprintk(")\n");
            if (mddev->level == LEVEL_MULTIPATH)
                  /* only need to write one superblock... */
                  break;
      }
      md_super_wait(mddev);
      /* if there was a failure, MD_CHANGE_DEVS was set, and we re-write super */

      spin_lock_irq(&mddev->write_lock);
      if (mddev->in_sync != sync_req ||
          test_bit(MD_CHANGE_DEVS, &mddev->flags)) {
            /* have to write it out again */
            spin_unlock_irq(&mddev->write_lock);
            goto repeat;
      }
      clear_bit(MD_CHANGE_PENDING, &mddev->flags);
      spin_unlock_irq(&mddev->write_lock);
      wake_up(&mddev->sb_wait);
      if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
            sysfs_notify(&mddev->kobj, NULL, "sync_completed");

}

/* words written to sysfs files may, or may not, be \n terminated.
 * We want to accept with case. For this we use cmd_match.
 */
static int cmd_match(const char *cmd, const char *str)
{
      /* See if cmd, written into a sysfs file, matches
       * str.  They must either be the same, or cmd can
       * have a trailing newline
       */
      while (*cmd && *str && *cmd == *str) {
            cmd++;
            str++;
      }
      if (*cmd == '\n')
            cmd++;
      if (*str || *cmd)
            return 0;
      return 1;
}

02081 struct rdev_sysfs_entry {
      struct attribute attr;
      ssize_t (*show)(mdk_rdev_t *, char *);
      ssize_t (*store)(mdk_rdev_t *, const char *, size_t);
};

static ssize_t
state_show(mdk_rdev_t *rdev, char *page)
{
      char *sep = "";
      size_t len = 0;

      if (test_bit(Faulty, &rdev->flags)) {
            len+= sprintf(page+len, "%sfaulty",sep);
            sep = ",";
      }
      if (test_bit(In_sync, &rdev->flags)) {
            len += sprintf(page+len, "%sin_sync",sep);
            sep = ",";
      }
      if (test_bit(WriteMostly, &rdev->flags)) {
            len += sprintf(page+len, "%swrite_mostly",sep);
            sep = ",";
      }
      if (test_bit(Blocked, &rdev->flags)) {
            len += sprintf(page+len, "%sblocked", sep);
            sep = ",";
      }
      if (!test_bit(Faulty, &rdev->flags) &&
          !test_bit(In_sync, &rdev->flags)) {
            len += sprintf(page+len, "%sspare", sep);
            sep = ",";
      }
      return len+sprintf(page+len, "\n");
}

static ssize_t
state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
{
      /* can write
       *  faulty  - simulates and error
       *  remove  - disconnects the device
       *  writemostly - sets write_mostly
       *  -writemostly - clears write_mostly
       *  blocked - sets the Blocked flag
       *  -blocked - clears the Blocked flag
       *  insync - sets Insync providing device isn't active
       */
      int err = -EINVAL;
      if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
            md_error(rdev->mddev, rdev);
            err = 0;
      } else if (cmd_match(buf, "remove")) {
            if (rdev->raid_disk >= 0)
                  err = -EBUSY;
            else {
                  mddev_t *mddev = rdev->mddev;
                  kick_rdev_from_array(rdev);
                  if (mddev->pers)
                        md_update_sb(mddev, 1);
                  md_new_event(mddev);
                  err = 0;
            }
      } else if (cmd_match(buf, "writemostly")) {
            set_bit(WriteMostly, &rdev->flags);
            err = 0;
      } else if (cmd_match(buf, "-writemostly")) {
            clear_bit(WriteMostly, &rdev->flags);
            err = 0;
      } else if (cmd_match(buf, "blocked")) {
            set_bit(Blocked, &rdev->flags);
            err = 0;
      } else if (cmd_match(buf, "-blocked")) {
            clear_bit(Blocked, &rdev->flags);
            wake_up(&rdev->blocked_wait);
            set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
            md_wakeup_thread(rdev->mddev->thread);

            err = 0;
      } else if (cmd_match(buf, "insync") && rdev->raid_disk == -1) {
            set_bit(In_sync, &rdev->flags);
            err = 0;
      }
      if (!err && rdev->sysfs_state)
            sysfs_notify_dirent(rdev->sysfs_state);
      return err ? err : len;
}
static struct rdev_sysfs_entry rdev_state =
__ATTR(state, S_IRUGO|S_IWUSR, state_show, state_store);

static ssize_t
errors_show(mdk_rdev_t *rdev, char *page)
{
      return sprintf(page, "%d\n", atomic_read(&rdev->corrected_errors));
}

static ssize_t
errors_store(mdk_rdev_t *rdev, const char *buf, size_t len)
{
      char *e;
      unsigned long n = simple_strtoul(buf, &e, 10);
      if (*buf && (*e == 0 || *e == '\n')) {
            atomic_set(&rdev->corrected_errors, n);
            return len;
      }
      return -EINVAL;
}
static struct rdev_sysfs_entry rdev_errors =
__ATTR(errors, S_IRUGO|S_IWUSR, errors_show, errors_store);

static ssize_t
slot_show(mdk_rdev_t *rdev, char *page)
{
      if (rdev->raid_disk < 0)
            return sprintf(page, "none\n");
      else
            return sprintf(page, "%d\n", rdev->raid_disk);
}

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 && slot == -1) {
            /* 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 (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 (rdev->mddev->pers) {
            mdk_rdev_t *rdev2;
            /* Activating a spare .. or possibly reactivating
             * if we ever get bitmaps working here.
             */

            if (rdev->raid_disk != -1)
                  return -EBUSY;

            if (rdev->mddev->pers->hot_add_disk == NULL)
                  return -EINVAL;

            list_for_each_entry(rdev2, &rdev->mddev->disks, same_set)
                  if (rdev2->raid_disk == slot)
                        return -EEXIST;

            rdev->raid_disk = slot;
            if (test_bit(In_sync, &rdev->flags))
                  rdev->saved_raid_disk = slot;
            else
                  rdev->saved_raid_disk = -1;
            err = rdev->mddev->pers->
                  hot_add_disk(rdev->mddev, rdev);
            if (err) {
                  rdev->raid_disk = -1;
                  return err;
            } else
                  sysfs_notify_dirent(rdev->sysfs_state);
            sprintf(nm, "rd%d", rdev->raid_disk);
            if (sysfs_create_link(&rdev->mddev->kobj, &rdev->kobj, nm))
                  printk(KERN_WARNING
                         "md: cannot register "
                         "%s for %s\n",
                         nm, mdname(rdev->mddev));

            /* don't wakeup anyone, leave that to userspace. */
      } 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);
            sysfs_notify_dirent(rdev->sysfs_state);
      }
      return len;
}


static struct rdev_sysfs_entry rdev_slot =
__ATTR(slot, S_IRUGO|S_IWUSR, slot_show, slot_store);

static ssize_t
offset_show(mdk_rdev_t *rdev, char *page)
{
      return sprintf(page, "%llu\n", (unsigned long long)rdev->data_offset);
}

static ssize_t
offset_store(mdk_rdev_t *rdev, const char *buf, size_t len)
{
      char *e;
      unsigned long long offset = simple_strtoull(buf, &e, 10);
      if (e==buf || (*e && *e != '\n'))
            return -EINVAL;
      if (rdev->mddev->pers && rdev->raid_disk >= 0)
            return -EBUSY;
      if (rdev->sectors && rdev->mddev->external)
            /* Must set offset before size, so overlap checks
             * can be sane */
            return -EBUSY;
      rdev->data_offset = offset;
      return len;
}

static struct rdev_sysfs_entry rdev_offset =
__ATTR(offset, S_IRUGO|S_IWUSR, offset_show, offset_store);

static ssize_t
rdev_size_show(mdk_rdev_t *rdev, char *page)
{
      return sprintf(page, "%llu\n", (unsigned long long)rdev->sectors / 2);
}

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 int strict_blocks_to_sectors(const char *buf, sector_t *sectors)
{
      unsigned long long blocks;
      sector_t new;

      if (strict_strtoull(buf, 10, &blocks) < 0)
            return -EINVAL;

      if (blocks & 1ULL << (8 * sizeof(blocks) - 1))
            return -EINVAL; /* sector conversion overflow */

      new = blocks * 2;
      if (new != blocks * 2)
            return -EINVAL; /* unsigned long long to sector_t overflow */

      *sectors = new;
      return 0;
}

static ssize_t
rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
{
      mddev_t *my_mddev = rdev->mddev;
      sector_t oldsectors = rdev->sectors;
      sector_t sectors;

      if (strict_blocks_to_sectors(buf, &sectors) < 0)
            return -EINVAL;
      if (my_mddev->pers && rdev->raid_disk >= 0) {
            if (my_mddev->persistent) {
                  sectors = super_types[my_mddev->major_version].
                        rdev_size_change(rdev, sectors);
                  if (!sectors)
                        return -EBUSY;
            } else if (!sectors)
                  sectors = (rdev->bdev->bd_inode->i_size >> 9) -
                        rdev->data_offset;
      }
      if (sectors < my_mddev->dev_sectors)
            return -EINVAL; /* component must fit device */

      rdev->sectors = sectors;
      if (sectors > oldsectors && my_mddev->external) {
            /* need to check that all other rdevs with the same ->bdev
             * do not overlap.  We need to unlock the mddev to avoid
             * a deadlock.  We have already changed rdev->sectors, and if
             * we have to change it back, we will have the lock again.
             */
            mddev_t *mddev;
            int overlap = 0;
            struct list_head *tmp;

            mddev_unlock(my_mddev);
            for_each_mddev(mddev, tmp) {
                  mdk_rdev_t *rdev2;

                  mddev_lock(mddev);
                  list_for_each_entry(rdev2, &mddev->disks, same_set)
                        if (test_bit(AllReserved, &rdev2->flags) ||
                            (rdev->bdev == rdev2->bdev &&
                             rdev != rdev2 &&
                             overlaps(rdev->data_offset, rdev->sectors,
                                    rdev2->data_offset,
                                    rdev2->sectors))) {
                              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 oldsectors back because we *know* it is
                   * safe, and trust userspace not to race with
                   * itself
                   */
                  rdev->sectors = oldsectors;
                  return -EBUSY;
            }
      }
      return len;
}

static struct rdev_sysfs_entry rdev_size =
__ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);

static struct attribute *rdev_default_attrs[] = {
      &rdev_state.attr,
      &rdev_errors.attr,
      &rdev_slot.attr,
      &rdev_offset.attr,
      &rdev_size.attr,
      NULL,
};
static ssize_t
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;

      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
rdev_attr_store(struct kobject *kobj, struct attribute *attr,
            const char *page, size_t length)
{
      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;
      rv = mddev ? mddev_lock(mddev): -EBUSY;
      if (!rv) {
            if (rdev->mddev == NULL)
                  rv = -EBUSY;
            else
                  rv = entry->store(rdev, page, length);
            mddev_unlock(mddev);
      }
      return rv;
}

static void rdev_free(struct kobject *ko)
{
      mdk_rdev_t *rdev = container_of(ko, mdk_rdev_t, kobj);
      kfree(rdev);
}
static struct sysfs_ops rdev_sysfs_ops = {
      .show       = rdev_attr_show,
      .store            = rdev_attr_store,
};
static struct kobj_type rdev_ktype = {
      .release    = rdev_free,
      .sysfs_ops  = &rdev_sysfs_ops,
      .default_attrs    = rdev_default_attrs,
};

/*
 * Import a device. If 'super_format' >= 0, then sanity check the superblock
 *
 * mark the device faulty if:
 *
 *   - the device is nonexistent (zero size)
 *   - the device has no valid superblock
 *
 * a faulty rdev _never_ has rdev->sb set.
 */
static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_minor)
{
      char b[BDEVNAME_SIZE];
      int err;
      mdk_rdev_t *rdev;
      sector_t size;

      rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
      if (!rdev) {
            printk(KERN_ERR "md: could not alloc mem for new device!\n");
            return ERR_PTR(-ENOMEM);
      }

      if ((err = alloc_disk_sb(rdev)))
            goto abort_free;

      err = lock_rdev(rdev, newdev, super_format == -2);
      if (err)
            goto abort_free;

      kobject_init(&rdev->kobj, &rdev_ktype);

      rdev->desc_nr = -1;
      rdev->saved_raid_disk = -1;
      rdev->raid_disk = -1;
      rdev->flags = 0;
      rdev->data_offset = 0;
      rdev->sb_events = 0;
      atomic_set(&rdev->nr_pending, 0);
      atomic_set(&rdev->read_errors, 0);
      atomic_set(&rdev->corrected_errors, 0);

      size = rdev->bdev->bd_inode->i_size >> BLOCK_SIZE_BITS;
      if (!size) {
            printk(KERN_WARNING 
                  "md: %s has zero or unknown size, marking faulty!\n",
                  bdevname(rdev->bdev,b));
            err = -EINVAL;
            goto abort_free;
      }

      if (super_format >= 0) {
            err = super_types[super_format].
                  load_super(rdev, NULL, super_minor);
            if (err == -EINVAL) {
                  printk(KERN_WARNING
                        "md: %s does not have a valid v%d.%d "
                         "superblock, not importing!\n",
                        bdevname(rdev->bdev,b),
                         super_format, super_minor);
                  goto abort_free;
            }
            if (err < 0) {
                  printk(KERN_WARNING 
                        "md: could not read %s's sb, not importing!\n",
                        bdevname(rdev->bdev,b));
                  goto abort_free;
            }
      }

      INIT_LIST_HEAD(&rdev->same_set);
      init_waitqueue_head(&rdev->blocked_wait);

      return rdev;

abort_free:
      if (rdev->sb_page) {
            if (rdev->bdev)
                  unlock_rdev(rdev);
            free_disk_sb(rdev);
      }
      kfree(rdev);
      return ERR_PTR(err);
}

/*
 * Check a full RAID array for plausibility
 */


static void analyze_sbs(mddev_t * mddev)
{
      int i;
      mdk_rdev_t *rdev, *freshest, *tmp;
      char b[BDEVNAME_SIZE];

      freshest = NULL;
      rdev_for_each(rdev, tmp, mddev)
            switch (super_types[mddev->major_version].
                  load_super(rdev, freshest, mddev->minor_version)) {
            case 1:
                  freshest = rdev;
                  break;
            case 0:
                  break;
            default:
                  printk( KERN_ERR \
                        "md: fatal superblock inconsistency in %s"
                        " -- removing from array\n", 
                        bdevname(rdev->bdev,b));
                  kick_rdev_from_array(rdev);
            }


      super_types[mddev->major_version].
            validate_super(mddev, freshest);

      i = 0;
      rdev_for_each(rdev, tmp, mddev) {
            if (rdev->desc_nr >= mddev->max_disks ||
                i > mddev->max_disks) {
                  printk(KERN_WARNING
                         "md: %s: %s: only %d devices permitted\n",
                         mdname(mddev), bdevname(rdev->bdev, b),
                         mddev->max_disks);
                  kick_rdev_from_array(rdev);
                  continue;
            }
            if (rdev != freshest)
                  if (super_types[mddev->major_version].
                      validate_super(mddev, rdev)) {
                        printk(KERN_WARNING "md: kicking non-fresh %s"
                              " from array!\n",
                              bdevname(rdev->bdev,b));
                        kick_rdev_from_array(rdev);
                        continue;
                  }
            if (mddev->level == LEVEL_MULTIPATH) {
                  rdev->desc_nr = i++;
                  rdev->raid_disk = rdev->desc_nr;
                  set_bit(In_sync, &rdev->flags);
            } else if (rdev->raid_disk >= mddev->raid_disks) {
                  rdev->raid_disk = -1;
                  clear_bit(In_sync, &rdev->flags);
            }
      }
}

static void md_safemode_timeout(unsigned long data);

static ssize_t
safe_delay_show(mddev_t *mddev, char *page)
{
      int msec = (mddev->safemode_delay*1000)/HZ;
      return sprintf(page, "%d.%03d\n", msec/1000, msec%1000);
}
static ssize_t
safe_delay_store(mddev_t *mddev, const char *cbuf, size_t len)
{
      int scale=1;
      int dot=0;
      int i;
      unsigned long msec;
      char buf[30];

      /* remove a period, and count digits after it */
      if (len >= sizeof(buf))
            return -EINVAL;
      strlcpy(buf, cbuf, sizeof(buf));
      for (i=0; i<len; i++) {
            if (dot) {
                  if (isdigit(buf[i])) {
                        buf[i-1] = buf[i];
                        scale *= 10;
                  }
                  buf[i] = 0;
            } else if (buf[i] == '.') {
                  dot=1;
                  buf[i] = 0;
            }
      }
      if (strict_strtoul(buf, 10, &msec) < 0)
            return -EINVAL;
      msec = (msec * 1000) / scale;
      if (msec == 0)
            mddev->safemode_delay = 0;
      else {
            unsigned long old_delay = mddev->safemode_delay;
            mddev->safemode_delay = (msec*HZ)/1000;
            if (mddev->safemode_delay == 0)
                  mddev->safemode_delay = 1;
            if (mddev->safemode_delay < old_delay)
                  md_safemode_timeout((unsigned long)mddev);
      }
      return len;
}
static struct md_sysfs_entry md_safe_delay =
__ATTR(safe_mode_delay, S_IRUGO|S_IWUSR,safe_delay_show, safe_delay_store);

static ssize_t
level_show(mddev_t *mddev, char *page)
{
      struct mdk_personality *p = mddev->pers;
      if (p)
            return sprintf(page, "%s\n", p->name);
      else if (mddev->clevel[0])
            return sprintf(page, "%s\n", mddev->clevel);
      else if (mddev->level != LEVEL_NONE)
            return sprintf(page, "%d\n", mddev->level);
      else
            return 0;
}

static ssize_t
level_store(mddev_t *mddev, const char *buf, size_t len)
{
      char level[16];
      ssize_t rv = len;
      struct mdk_personality *pers;
      void *priv;
      mdk_rdev_t *rdev;

      if (mddev->pers == NULL) {
            if (len == 0)
                  return 0;
            if (len >= sizeof(mddev->clevel))
                  return -ENOSPC;
            strncpy(mddev->clevel, buf, len);
            if (mddev->clevel[len-1] == '\n')
                  len--;
            mddev->clevel[len] = 0;
            mddev->level = LEVEL_NONE;
            return rv;
      }

      /* request to change the personality.  Need to ensure:
       *  - array is not engaged in resync/recovery/reshape
       *  - old personality can be suspended
       *  - new personality will access other array.
       */

      if (mddev->sync_thread || mddev->reshape_position != MaxSector)
            return -EBUSY;

      if (!mddev->pers->quiesce) {
            printk(KERN_WARNING "md: %s: %s does not support online personality change\n",
                   mdname(mddev), mddev->pers->name);
            return -EINVAL;
      }

      /* Now find the new personality */
      if (len == 0 || len >= sizeof(level))
            return -EINVAL;
      strncpy(level, buf, len);
      if (level[len-1] == '\n')
            len--;
      level[len] = 0;

      request_module("md-%s", level);
      spin_lock(&pers_lock);
      pers = find_pers(LEVEL_NONE, level);
      if (!pers || !try_module_get(pers->owner)) {
            spin_unlock(&pers_lock);
            printk(KERN_WARNING "md: personality %s not loaded\n", level);
            return -EINVAL;
      }
      spin_unlock(&pers_lock);

      if (pers == mddev->pers) {
            /* Nothing to do! */
            module_put(pers->owner);
            return rv;
      }
      if (!pers->takeover) {
            module_put(pers->owner);
            printk(KERN_WARNING "md: %s: %s does not support personality takeover\n",
                   mdname(mddev), level);
            return -EINVAL;
      }

      /* ->takeover must set new_* and/or delta_disks
       * if it succeeds, and may set them when it fails.
       */
      priv = pers->takeover(mddev);
      if (IS_ERR(priv)) {
            mddev->new_level = mddev->level;
            mddev->new_layout = mddev->layout;
            mddev->new_chunk_sectors = mddev->chunk_sectors;
            mddev->raid_disks -= mddev->delta_disks;
            mddev->delta_disks = 0;
            module_put(pers->owner);
            printk(KERN_WARNING "md: %s: %s would not accept array\n",
                   mdname(mddev), level);
            return PTR_ERR(priv);
      }

      /* Looks like we have a winner */
      mddev_suspend(mddev);
      mddev->pers->stop(mddev);
      module_put(mddev->pers->owner);
      /* Invalidate devices that are now superfluous */
      list_for_each_entry(rdev, &mddev->disks, same_set)
            if (rdev->raid_disk >= mddev->raid_disks) {
                  rdev->raid_disk = -1;
                  clear_bit(In_sync, &rdev->flags);
            }
      mddev->pers = pers;
      mddev->private = priv;
      strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
      mddev->level = mddev->new_level;
      mddev->layout = mddev->new_layout;
      mddev->chunk_sectors = mddev->new_chunk_sectors;
      mddev->delta_disks = 0;
      pers->run(mddev);
      mddev_resume(mddev);
      set_bit(MD_CHANGE_DEVS, &mddev->flags);
      set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
      md_wakeup_thread(mddev->thread);
      return rv;
}

static struct md_sysfs_entry md_level =
__ATTR(level, S_IRUGO|S_IWUSR, level_show, level_store);


static ssize_t
layout_show(mddev_t *mddev, char *page)
{
      /* just a number, not meaningful for all levels */
      if (mddev->reshape_position != MaxSector &&
          mddev->layout != mddev->new_layout)
            return sprintf(page, "%d (%d)\n",
                         mddev->new_layout, mddev->layout);
      return sprintf(page, "%d\n", mddev->layout);
}

static ssize_t
layout_store(mddev_t *mddev, const char *buf, size_t len)
{
      char *e;
      unsigned long n = simple_strtoul(buf, &e, 10);

      if (!*buf || (*e && *e != '\n'))
            return -EINVAL;

      if (mddev->pers) {
            int err;
            if (mddev->pers->check_reshape == NULL)
                  return -EBUSY;
            mddev->new_layout = n;
            err = mddev->pers->check_reshape(mddev);
            if (err) {
                  mddev->new_layout = mddev->layout;
                  return err;
            }
      } else {
            mddev->new_layout = n;
            if (mddev->reshape_position == MaxSector)
                  mddev->layout = n;
      }
      return len;
}
static struct md_sysfs_entry md_layout =
__ATTR(layout, S_IRUGO|S_IWUSR, layout_show, layout_store);


static ssize_t
raid_disks_show(mddev_t *mddev, char *page)
{
      if (mddev->raid_disks == 0)
            return 0;
      if (mddev->reshape_position != MaxSector &&
          mddev->delta_disks != 0)
            return sprintf(page, "%d (%d)\n", mddev->raid_disks,
                         mddev->raid_disks - mddev->delta_disks);
      return sprintf(page, "%d\n", mddev->raid_disks);
}

static int update_raid_disks(mddev_t *mddev, int raid_disks);

static ssize_t
raid_disks_store(mddev_t *mddev, const char *buf, size_t len)
{
      char *e;
      int rv = 0;
      unsigned long n = simple_strtoul(buf, &e, 10);

      if (!*buf || (*e && *e != '\n'))
            return -EINVAL;

      if (mddev->pers)
            rv = update_raid_disks(mddev, n);
      else if (mddev->reshape_position != MaxSector) {
            int olddisks = mddev->raid_disks - mddev->delta_disks;
            mddev->delta_disks = n - olddisks;
            mddev->raid_disks = n;
      } else
            mddev->raid_disks = n;
      return rv ? rv : len;
}
static struct md_sysfs_entry md_raid_disks =
__ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);

static ssize_t
chunk_size_show(mddev_t *mddev, char *page)
{
      if (mddev->reshape_position != MaxSector &&
          mddev->chunk_sectors != mddev->new_chunk_sectors)
            return sprintf(page, "%d (%d)\n",
                         mddev->new_chunk_sectors << 9,
                         mddev->chunk_sectors << 9);
      return sprintf(page, "%d\n", mddev->chunk_sectors << 9);
}

static ssize_t
chunk_size_store(mddev_t *mddev, const char *buf, size_t len)
{
      char *e;
      unsigned long n = simple_strtoul(buf, &e, 10);

      if (!*buf || (*e && *e != '\n'))
            return -EINVAL;

      if (mddev->pers) {
            int err;
            if (mddev->pers->check_reshape == NULL)
                  return -EBUSY;
            mddev->new_chunk_sectors = n >> 9;
            err = mddev->pers->check_reshape(mddev);
            if (err) {
                  mddev->new_chunk_sectors = mddev->chunk_sectors;
                  return err;
            }
      } else {
            mddev->new_chunk_sectors = n >> 9;
            if (mddev->reshape_position == MaxSector)
                  mddev->chunk_sectors = n >> 9;
      }
      return len;
}
static struct md_sysfs_entry md_chunk_size =
__ATTR(chunk_size, S_IRUGO|S_IWUSR, chunk_size_show, chunk_size_store);

static ssize_t
resync_start_show(mddev_t *mddev, char *page)
{
      if (mddev->recovery_cp == MaxSector)
            return sprintf(page, "none\n");
      return sprintf(page, "%llu\n", (unsigned long long)mddev->recovery_cp);
}

static ssize_t
resync_start_store(mddev_t *mddev, const char *buf, size_t len)
{
      char *e;
      unsigned long long n = simple_strtoull(buf, &e, 10);

      if (mddev->pers)
            return -EBUSY;
      if (!*buf || (*e && *e != '\n'))
            return -EINVAL;

      mddev->recovery_cp = n;
      return len;
}
static struct md_sysfs_entry md_resync_start =
__ATTR(resync_start, S_IRUGO|S_IWUSR, resync_start_show, resync_start_store);

/*
 * The array state can be:
 *
 * clear
 *     No devices, no size, no level
 *     Equivalent to STOP_ARRAY ioctl
 * inactive
 *     May have some settings, but array is not active
 *        all IO results in error
 *     When written, doesn't tear down array, but just stops it
 * suspended (not supported yet)
 *     All IO requests will block. The array can be reconfigured.
 *     Writing this, if accepted, will block until array is quiescent
 * readonly
 *     no resync can happen.  no superblocks get written.
 *     write requests fail
 * read-auto
 *     like readonly, but behaves like 'clean' on a write request.
 *
 * clean - no pending writes, but otherwise active.
 *     When written to inactive array, starts without resync
 *     If a write request arrives then
 *       if metadata is known, mark 'dirty' and switch to 'active'.
 *       if not known, block and switch to write-pending
 *     If written to an active array that has pending writes, then fails.
 * active
 *     fully active: IO and resync can be happening.
 *     When written to inactive array, starts with resync
 *
 * write-pending
 *     clean, but writes are blocked waiting for 'active' to be written.
 *
 * active-idle
 *     like active, but no writes have been seen for a while (100msec).
 *
 */
enum array_state { clear, inactive, suspended, readonly, read_auto, clean, active,
               write_pending, active_idle, bad_word};
static char *array_states[] = {
      "clear", "inactive", "suspended", "readonly", "read-auto", "clean", "active",
      "write-pending", "active-idle", NULL };

static int match_word(const char *word, char **list)
{
      int n;
      for (n=0; list[n]; n++)
            if (cmd_match(word, list[n]))
                  break;
      return n;
}

static ssize_t
array_state_show(mddev_t *mddev, char *page)
{
      enum array_state st = inactive;

      if (mddev->pers)
            switch(mddev->ro) {
            case 1:
                  st = readonly;
                  break;
            case 2:
                  st = read_auto;
                  break;
            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
                        st = active;
            }
      else {
            if (list_empty(&mddev->disks) &&
                mddev->raid_disks == 0 &&
                mddev->dev_sectors == 0)
                  st = clear;
            else
                  st = inactive;
      }
      return sprintf(page, "%s\n", array_states[st]);
}

static int do_md_stop(mddev_t * mddev, int ro, int is_open);
static int do_md_run(mddev_t * mddev);
static int restart_array(mddev_t *mddev);

static ssize_t
array_state_store(mddev_t *mddev, const char *buf, size_t len)
{
      int err = -EINVAL;
      enum array_state st = match_word(buf, array_states);
      switch(st) {
      case bad_word:
            break;
      case clear:
            /* stopping an active array */
            if (atomic_read(&mddev->openers) > 0)
                  return -EBUSY;
            err = do_md_stop(mddev, 0, 0);
            break;
      case inactive:
            /* stopping an active array */
            if (mddev->pers) {
                  if (atomic_read(&mddev->openers) > 0)
                        return -EBUSY;
                  err = do_md_stop(mddev, 2, 0);
            } else
                  err = 0; /* already inactive */
            break;
      case suspended:
            break; /* not supported yet */
      case readonly:
            if (mddev->pers)
                  err = do_md_stop(mddev, 1, 0);
            else {
                  mddev->ro = 1;
                  set_disk_ro(mddev->gendisk, 1);
                  err = do_md_run(mddev);
            }
            break;
      case read_auto:
            if (mddev->pers) {
                  if (mddev->ro == 0)
                        err = do_md_stop(mddev, 1, 0);
                  else if (mddev->ro == 1)
                        err = restart_array(mddev);
                  if (err == 0) {
                        mddev->ro = 2;
                        set_disk_ro(mddev->gendisk, 0);
                  }
            } else {
                  mddev->ro = 2;
                  err = do_md_run(mddev);
            }
            break;
      case clean:
            if (mddev->pers) {
                  restart_array(mddev);
                  spin_lock_irq(&mddev->write_lock);
                  if (atomic_read(&mddev->writes_pending) == 0) {
                        if (mddev->in_sync == 0) {
                              mddev->in_sync = 1;
                              if (mddev->safemode == 1)
                                    mddev->safemode = 0;
                              if (mddev->persistent)
                                    set_bit(MD_CHANGE_CLEAN,
                                          &mddev->flags);
                        }
                        err = 0;
                  } else
                        err = -EBUSY;
                  spin_unlock_irq(&mddev->write_lock);
            } else
                  err = -EINVAL;
            break;
      case active:
            if (mddev->pers) {
                  restart_array(mddev);
                  if (mddev->external)
                        clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
                  wake_up(&mddev->sb_wait);
                  err = 0;
            } else {
                  mddev->ro = 0;
                  set_disk_ro(mddev->gendisk, 0);
                  err = do_md_run(mddev);
            }
            break;
      case write_pending:
      case active_idle:
            /* these cannot be set */
            break;
      }
      if (err)
            return err;
      else {
            sysfs_notify_dirent(mddev->sysfs_state);
            return len;
      }
}
static struct md_sysfs_entry md_array_state =
__ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);

static ssize_t
null_show(mddev_t *mddev, char *page)
{
      return -EINVAL;
}

static ssize_t
new_dev_store(mddev_t *mddev, const char *buf, size_t len)
{
      /* buf must be %d:%d\n? giving major and minor numbers */
      /* The new device is added to the array.
       * If the array has a persistent superblock, we read the
       * superblock to initialise info and check validity.
       * Otherwise, only checking done is that in bind_rdev_to_array,
       * which mainly checks size.
       */
      char *e;
      int major = simple_strtoul(buf, &e, 10);
      int minor;
      dev_t dev;
      mdk_rdev_t *rdev;
      int err;

      if (!*buf || *e != ':' || !e[1] || e[1] == '\n')
            return -EINVAL;
      minor = simple_strtoul(e+1, &e, 10);
      if (*e && *e != '\n')
            return -EINVAL;
      dev = MKDEV(major, minor);
      if (major != MAJOR(dev) ||
          minor != MINOR(dev))
            return -EOVERFLOW;


      if (mddev->persistent) {
            rdev = md_import_device(dev, mddev->major_version,
                              mddev->minor_version);
            if (!IS_ERR(rdev) && !list_empty(&mddev->disks)) {
                  mdk_rdev_t *rdev0 = list_entry(mddev->disks.next,
                                           mdk_rdev_t, same_set);
                  err = super_types[mddev->major_version]
                        .load_super(rdev, rdev0, mddev->minor_version);
                  if (err < 0)
                        goto out;
            }
      } else if (mddev->external)
            rdev = md_import_device(dev, -2, -1);
      else
            rdev = md_import_device(dev, -1, -1);

      if (IS_ERR(rdev))
            return PTR_ERR(rdev);
      err = bind_rdev_to_array(rdev, mddev);
 out:
      if (err)
            export_rdev(rdev);
      return err ? err : len;
}

static struct md_sysfs_entry md_new_device =
__ATTR(new_dev, S_IWUSR, null_show, new_dev_store);

static ssize_t
bitmap_store(mddev_t *mddev, const char *buf, size_t len)
{
      char *end;
      unsigned long chunk, end_chunk;

      if (!mddev->bitmap)
            goto out;
      /* buf should be <chunk> <chunk> ... or <chunk>-<chunk> ... (range) */
      while (*buf) {
            chunk = end_chunk = simple_strtoul(buf, &end, 0);
            if (buf == end) break;
            if (*end == '-') { /* range */
                  buf = end + 1;
                  end_chunk = simple_strtoul(buf, &end, 0);
                  if (buf == end) break;
            }
            if (*end && !isspace(*end)) break;
            bitmap_dirty_bits(mddev->bitmap, chunk, end_chunk);
            buf = end;
            while (isspace(*buf)) buf++;
      }
      bitmap_unplug(mddev->bitmap); /* flush the bits to disk */
out:
      return len;
}

static struct md_sysfs_entry md_bitmap =
__ATTR(bitmap_set_bits, S_IWUSR, null_show, bitmap_store);

static ssize_t
size_show(mddev_t *mddev, char *page)
{
      return sprintf(page, "%llu\n",
            (unsigned long long)mddev->dev_sectors / 2);
}

static int update_size(mddev_t *mddev, sector_t num_sectors);

static ssize_t
size_store(mddev_t *mddev, const char *buf, size_t len)
{
      /* If array is inactive, we can reduce the component size, but
       * not increase it (except from 0).
       * If array is active, we can try an on-line resize
       */
      sector_t sectors;
      int err = strict_blocks_to_sectors(buf, &sectors);

      if (err < 0)
            return err;
      if (mddev->pers) {
            err = update_size(mddev, sectors);
            md_update_sb(mddev, 1);
      } else {
            if (mddev->dev_sectors == 0 ||
                mddev->dev_sectors > sectors)
                  mddev->dev_sectors = sectors;
            else
                  err = -ENOSPC;
      }
      return err ? err : len;
}

static struct md_sysfs_entry md_size =
__ATTR(component_size, S_IRUGO|S_IWUSR, size_show, size_store);


/* Metdata version.
 * 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
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");
}

static ssize_t
metadata_store(mddev_t *mddev, const char *buf, size_t len)
{
      int major, minor;
      char *e;
      /* Changing the details of 'external' metadata is
       * always permitted.  Otherwise there must be
       * no devices attached to the array.
       */
      if (mddev->external && strncmp(buf, "external:", 9) == 0)
            ;
      else if (!list_empty(&mddev->disks))
            return -EBUSY;

      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;
      }
      major = simple_strtoul(buf, &e, 10);
      if (e==buf || *e != '.')
            return -EINVAL;
      buf = e+1;
      minor = simple_strtoul(buf, &e, 10);
      if (e==buf || (*e && *e != '\n') )
            return -EINVAL;
      if (major >= ARRAY_SIZE(super_types) || super_types[major].name == NULL)
            return -ENOENT;
      mddev->major_version = major;
      mddev->minor_version = minor;
      mddev->persistent = 1;
      mddev->external = 0;
      return len;
}

static struct md_sysfs_entry md_metadata =
__ATTR(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store);

static ssize_t
action_show(mddev_t *mddev, char *page)
{
      char *type = "idle";
      if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
            type = "frozen";
      else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
          (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
            if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
                  type = "reshape";
            else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
                  if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
                        type = "resync";
                  else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
                        type = "check";
                  else
                        type = "repair";
            } else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
                  type = "recover";
      }
      return sprintf(page, "%s\n", type);
}

static ssize_t
action_store(mddev_t *mddev, const char *page, size_t len)
{
      if (!mddev->pers || !mddev->pers->sync_request)
            return -EINVAL;

      if (cmd_match(page, "frozen"))
            set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
      else
            clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);

      if (cmd_match(page, "idle") || cmd_match(page, "frozen")) {
            if (mddev->sync_thread) {
                  set_bit(MD_RECOVERY_INTR, &mddev->recovery);
                  md_unregister_thread(mddev->sync_thread);
                  mddev->sync_thread = NULL;
                  mddev->recovery = 0;
            }
      } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
               test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
            return -EBUSY;
      else if (cmd_match(page, "resync"))
            set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
      else if (cmd_match(page, "recover")) {
            set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
            set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
      } else if (cmd_match(page, "reshape")) {
            int err;
            if (mddev->pers->start_reshape == NULL)
                  return -EINVAL;
            err = mddev->pers->start_reshape(mddev);
            if (err)
                  return err;
            sysfs_notify(&mddev->kobj, NULL, "degraded");
      } else {
            if (cmd_match(page, "check"))
                  set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
            else if (!cmd_match(page, "repair"))
                  return -EINVAL;
            set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
            set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
      }
      set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
      md_wakeup_thread(mddev->thread);
      sysfs_notify_dirent(mddev->sysfs_action);
      return len;
}

static ssize_t
mismatch_cnt_show(mddev_t *mddev, char *page)
{
      return sprintf(page, "%llu\n",
                   (unsigned long long) mddev->resync_mismatches);
}

static struct md_sysfs_entry md_scan_mode =
__ATTR(sync_action, S_IRUGO|S_IWUSR, action_show, action_store);


static struct md_sysfs_entry md_mismatches = __ATTR_RO(mismatch_cnt);

static ssize_t
sync_min_show(mddev_t *mddev, char *page)
{
      return sprintf(page, "%d (%s)\n", speed_min(mddev),
                   mddev->sync_speed_min ? "local": "system");
}

static ssize_t
sync_min_store(mddev_t *mddev, const char *buf, size_t len)
{
      int min;
      char *e;
      if (strncmp(buf, "system", 6)==0) {
            mddev->sync_speed_min = 0;
            return len;
      }
      min = simple_strtoul(buf, &e, 10);
      if (buf == e || (*e && *e != '\n') || min <= 0)
            return -EINVAL;
      mddev->sync_speed_min = min;
      return len;
}

static struct md_sysfs_entry md_sync_min =
__ATTR(sync_speed_min, S_IRUGO|S_IWUSR, sync_min_show, sync_min_store);

static ssize_t
sync_max_show(mddev_t *mddev, char *page)
{
      return sprintf(page, "%d (%s)\n", speed_max(mddev),
                   mddev->sync_speed_max ? "local": "system");
}

static ssize_t
sync_max_store(mddev_t *mddev, const char *buf, size_t len)
{
      int max;
      char *e;
      if (strncmp(buf, "system", 6)==0) {
            mddev->sync_speed_max = 0;
            return len;
      }
      max = simple_strtoul(buf, &e, 10);
      if (buf == e || (*e && *e != '\n') || max <= 0)
            return -EINVAL;
      mddev->sync_speed_max = max;
      return len;
}

static struct md_sysfs_entry md_sync_max =
__ATTR(sync_speed_max, S_IRUGO|S_IWUSR, sync_max_show, sync_max_store);

static ssize_t
degraded_show(mddev_t *mddev, char *page)
{
      return sprintf(page, "%d\n", mddev->degraded);
}
static struct md_sysfs_entry md_degraded = __ATTR_RO(degraded);

static ssize_t
sync_force_parallel_show(mddev_t *mddev, char *page)
{
      return sprintf(page, "%d\n", mddev->parallel_resync);
}

static ssize_t
sync_force_parallel_store(mddev_t *mddev, const char *buf, size_t len)
{
      long n;

      if (strict_strtol(buf, 10, &n))
            return -EINVAL;

      if (n != 0 && n != 1)
            return -EINVAL;

      mddev->parallel_resync = n;

      if (mddev->sync_thread)
            wake_up(&resync_wait);

      return len;
}

/* force parallel resync, even with shared block devices */
static struct md_sysfs_entry md_sync_force_parallel =
__ATTR(sync_force_parallel, S_IRUGO|S_IWUSR,
       sync_force_parallel_show, sync_force_parallel_store);

static ssize_t
sync_speed_show(mddev_t *mddev, char *page)
{
      unsigned long resync, dt, db;
      if (mddev->curr_resync == 0)
            return sprintf(page, "none\n");
      resync = mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active);
      dt = (jiffies - mddev->resync_mark) / HZ;
      if (!dt) dt++;
      db = resync - mddev->resync_mark_cnt;
      return sprintf(page, "%lu\n", db/dt/2); /* K/sec */
}

static struct md_sysfs_entry md_sync_speed = __ATTR_RO(sync_speed);

static ssize_t
sync_completed_show(mddev_t *mddev, char *page)
{
      unsigned long max_sectors, resync;

      if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
            return sprintf(page, "none\n");

      if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
            max_sectors = mddev->resync_max_sectors;
      else
            max_sectors = mddev->dev_sectors;

      resync = mddev->curr_resync_completed;
      return sprintf(page, "%lu / %lu\n", resync, max_sectors);
}

static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);

static ssize_t
min_sync_show(mddev_t *mddev, char *page)
{
      return sprintf(page, "%llu\n",
                   (unsigned long long)mddev->resync_min);
}
static ssize_t
min_sync_store(mddev_t *mddev, const char *buf, size_t len)
{
      unsigned long long min;
      if (strict_strtoull(buf, 10, &min))
            return -EINVAL;
      if (min > mddev->resync_max)
            return -EINVAL;
      if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
            return -EBUSY;

      /* Must be a multiple of chunk_size */
      if (mddev->chunk_sectors) {
            sector_t temp = min;
            if (sector_div(temp, mddev->chunk_sectors))
                  return -EINVAL;
      }
      mddev->resync_min = min;

      return len;
}

static struct md_sysfs_entry md_min_sync =
__ATTR(sync_min, S_IRUGO|S_IWUSR, min_sync_show, min_sync_store);

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 {
            unsigned long long max;
            if (strict_strtoull(buf, 10, &max))
                  return -EINVAL;
            if (max < mddev->resync_min)
                  return -EINVAL;
            if (max < mddev->resync_max &&
                mddev->ro == 0 &&
                test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
                  return -EBUSY;

            /* Must be a multiple of chunk_size */
            if (mddev->chunk_sectors) {
                  sector_t temp = max;
                  if (sector_div(temp, mddev->chunk_sectors))
                        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)
{
      return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_lo);
}

static ssize_t
suspend_lo_store(mddev_t *mddev, const char *buf, size_t len)
{
      char *e;
      unsigned long long new = simple_strtoull(buf, &e, 10);

      if (mddev->pers == NULL || 
          mddev->pers->quiesce == NULL)
            return -EINVAL;
      if (buf == e || (*e && *e != '\n'))
            return -EINVAL;
      if (new >= mddev->suspend_hi ||
          (new > mddev->suspend_lo && new < mddev->suspend_hi)) {
            mddev->suspend_lo = new;
            mddev->pers->quiesce(mddev, 2);
            return len;
      } else
            return -EINVAL;
}
static struct md_sysfs_entry md_suspend_lo =
__ATTR(suspend_lo, S_IRUGO|S_IWUSR, suspend_lo_show, suspend_lo_store);


static ssize_t
suspend_hi_show(mddev_t *mddev, char *page)
{
      return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_hi);
}

static ssize_t
suspend_hi_store(mddev_t *mddev, const char *buf, size_t len)
{
      char *e;
      unsigned long long new = simple_strtoull(buf, &e, 10);

      if (mddev->pers == NULL ||
          mddev->pers->quiesce == NULL)
            return -EINVAL;
      if (buf == e || (*e && *e != '\n'))
            return -EINVAL;
      if ((new <= mddev->suspend_lo && mddev->suspend_lo >= mddev->suspend_hi) ||
          (new > mddev->suspend_lo && new > mddev->suspend_hi)) {
            mddev->suspend_hi = new;
            mddev->pers->quiesce(mddev, 1);
            mddev->pers->quiesce(mddev, 0);
            return len;
      } else
            return -EINVAL;
}
static struct md_sysfs_entry md_suspend_hi =
__ATTR(suspend_hi, S_IRUGO|S_IWUSR, suspend_hi_show, suspend_hi_store);

static ssize_t
reshape_position_show(mddev_t *mddev, char *page)
{
      if (mddev->reshape_position != MaxSector)
            return sprintf(page, "%llu\n",
                         (unsigned long long)mddev->reshape_position);
      strcpy(page, "none\n");
      return 5;
}

static ssize_t
reshape_position_store(mddev_t *mddev, const char *buf, size_t len)
{
      char *e;
      unsigned long long new = simple_strtoull(buf, &e, 10);
      if (mddev->pers)
            return -EBUSY;
      if (buf == e || (*e && *e != '\n'))
            return -EINVAL;
      mddev->reshape_position = new;
      mddev->delta_disks = 0;
      mddev->new_level = mddev->level;
      mddev->new_layout = mddev->layout;
      mddev->new_chunk_sectors = mddev->chunk_sectors;
      return len;
}

static struct md_sysfs_entry md_reshape_position =
__ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
       reshape_position_store);

static ssize_t
array_size_show(mddev_t *mddev, char *page)
{
      if (mddev->external_size)
            return sprintf(page, "%llu\n",
                         (unsigned long long)mddev->array_sectors/2);
      else
            return sprintf(page, "default\n");
}

static ssize_t
array_size_store(mddev_t *mddev, const char *buf, size_t len)
{
      sector_t sectors;

      if (strncmp(buf, "default", 7) == 0) {
            if (mddev->pers)
                  sectors = mddev->pers->size(mddev, 0, 0);
            else
                  sectors = mddev->array_sectors;

            mddev->external_size = 0;
      } else {
            if (strict_blocks_to_sectors(buf, &sectors) < 0)
                  return -EINVAL;
            if (mddev->pers && mddev->pers->size(mddev, 0, 0) < sectors)
                  return -E2BIG;

            mddev->external_size = 1;
      }

      mddev->array_sectors = sectors;
      set_capacity(mddev->gendisk, mddev->array_sectors);
      if (mddev->pers)
            revalidate_disk(mddev->gendisk);

      return len;
}

static struct md_sysfs_entry md_array_size =
__ATTR(array_size, S_IRUGO|S_IWUSR, array_size_show,
       array_size_store);

static struct attribute *md_default_attrs[] = {
      &md_level.attr,
      &md_layout.attr,
      &md_raid_disks.attr,
      &md_chunk_size.attr,
      &md_size.attr,
      &md_resync_start.attr,
      &md_metadata.attr,
      &md_new_device.attr,
      &md_safe_delay.attr,
      &md_array_state.attr,
      &md_reshape_position.attr,
      &md_array_size.attr,
      NULL,
};

static struct attribute *md_redundancy_attrs[] = {
      &md_scan_mode.attr,
      &md_mismatches.attr,
      &md_sync_min.attr,
      &md_sync_max.attr,
      &md_sync_speed.attr,
      &md_sync_force_parallel.attr,
      &md_sync_completed.attr,
      &md_min_sync.attr,
      &md_max_sync.attr,
      &md_suspend_lo.attr,
      &md_suspend_hi.attr,
      &md_bitmap.attr,
      &md_degraded.attr,
      NULL,
};
static struct attribute_group md_redundancy_group = {
      .name = NULL,
      .attrs = md_redundancy_attrs,
};


static ssize_t
md_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
{
      struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
      mddev_t *mddev = container_of(kobj, struct mddev_s, kobj);
      ssize_t rv;

      if (!entry->show)
            return -EIO;
      rv = mddev_lock(mddev);
      if (!rv) {
            rv = entry->show(mddev, page);
            mddev_unlock(mddev);
      }
      return rv;
}

static ssize_t
md_attr_store(struct kobject *kobj, struct attribute *attr,
            const char *page, size_t length)
{
      struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
      mddev_t *mddev = container_of(kobj, struct mddev_s, kobj);
      ssize_t rv;

      if (!entry->store)
            return -EIO;
      if (!capable(CAP_SYS_ADMIN))
            return -EACCES;
      rv = mddev_lock(mddev);
      if (mddev->hold_active == UNTIL_IOCTL)
            mddev->hold_active = 0;
      if (!rv) {
            rv = entry->store(mddev, page, length);
            mddev_unlock(mddev);
      }
      return rv;
}

static void md_free(struct kobject *ko)
{
      mddev_t *mddev = container_of(ko, mddev_t, kobj);

      if (mddev->sysfs_state)
            sysfs_put(mddev->sysfs_state);

      if (mddev->gendisk) {
            del_gendisk(mddev->gendisk);
            put_disk(mddev->gendisk);
      }
      if (mddev->queue)
            blk_cleanup_queue(mddev->queue);

      kfree(mddev);
}

static struct sysfs_ops md_sysfs_ops = {
      .show = md_attr_show,
      .store      = md_attr_store,
};
static struct kobj_type md_ktype = {
      .release    = md_free,
      .sysfs_ops  = &md_sysfs_ops,
      .default_attrs    = md_default_attrs,
};

int mdp_major = 0;

static void mddev_delayed_delete(struct work_struct *ws)
{
      mddev_t *mddev = container_of(ws, mddev_t, del_work);

      if (mddev->private == &md_redundancy_group) {
            sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
            if (mddev->sysfs_action)
                  sysfs_put(mddev->sysfs_action);
            mddev->sysfs_action = NULL;
            mddev->private = NULL;
      }
      kobject_del(&mddev->kobj);
      kobject_put(&mddev->kobj);
}

static int md_alloc(dev_t dev, char *name)
{
      static DEFINE_MUTEX(disks_mutex);
      mddev_t *mddev = mddev_find(dev);
      struct gendisk *disk;
      int partitioned;
      int shift;
      int unit;
      int error;

      if (!mddev)
            return -ENODEV;

      partitioned = (MAJOR(mddev->unit) != MD_MAJOR);
      shift = partitioned ? MdpMinorShift : 0;
      unit = MINOR(mddev->unit) >> shift;

      /* wait for any previous instance if this device
       * to be completed removed (mddev_delayed_delete).
       */
      flush_scheduled_work();

      mutex_lock(&disks_mutex);
      error = -EEXIST;
      if (mddev->gendisk)
            goto abort;

      if (name) {
            /* Need to ensure that 'name' is not a duplicate.
             */
            mddev_t *mddev2;
            spin_lock(&all_mddevs_lock);

            list_for_each_entry(mddev2, &all_mddevs, all_mddevs)
                  if (mddev2->gendisk &&
                      strcmp(mddev2->gendisk->disk_name, name) == 0) {
                        spin_unlock(&all_mddevs_lock);
                        goto abort;
                  }
            spin_unlock(&all_mddevs_lock);
      }

      error = -ENOMEM;
      mddev->queue = blk_alloc_queue(GFP_KERNEL);
      if (!mddev->queue)
            goto abort;
      mddev->queue->queuedata = mddev;

      /* Can be unlocked because the queue is new: no concurrency */
      queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, mddev->queue);

      blk_queue_make_request(mddev->queue, md_make_request);

      disk = alloc_disk(1 << shift);
      if (!disk) {
            blk_cleanup_queue(mddev->queue);
            mddev->queue = NULL;
            goto abort;
      }
      disk->major = MAJOR(mddev->unit);
      disk->first_minor = unit << shift;
      if (name)
            strcpy(disk->disk_name, name);
      else if (partitioned)
            sprintf(disk->disk_name, "md_d%d", unit);
      else
            sprintf(disk->disk_name, "md%d", unit);
      disk->fops = &md_fops;
      disk->private_data = mddev;
      disk->queue = mddev->queue;
      /* Allow extended partitions.  This makes the
       * 'mdp' device redundant, but we can't really
       * remove it now.
       */
      disk->flags |= GENHD_FL_EXT_DEVT;
      add_disk(disk);
      mddev->gendisk = disk;
      error = kobject_init_and_add(&mddev->kobj, &md_ktype,
                             &disk_to_dev(disk)->kobj, "%s", "md");
      if (error) {
            /* This isn't possible, but as kobject_init_and_add is marked
             * __must_check, we must do something with the result
             */
            printk(KERN_WARNING "md: cannot register %s/md - name in use\n",
                   disk->disk_name);
            error = 0;
      }
 abort:
      mutex_unlock(&disks_mutex);
      if (!error) {
            kobject_uevent(&mddev->kobj, KOBJ_ADD);
            mddev->sysfs_state = sysfs_get_dirent(mddev->kobj.sd, "array_state");
      }
      mddev_put(mddev);
      return error;
}

static struct kobject *md_probe(dev_t dev, int *part, void *data)
{
      md_alloc(dev, NULL);
      return NULL;
}

static int add_named_array(const char *val, struct kernel_param *kp)
{
      /* val must be "md_*" where * is not all digits.
       * We allocate an array with a large free minor number, and
       * set the name to val.  val must not already be an active name.
       */
      int len = strlen(val);
      char buf[DISK_NAME_LEN];

      while (len && val[len-1] == '\n')
            len--;
      if (len >= DISK_NAME_LEN)
            return -E2BIG;
      strlcpy(buf, val, len+1);
      if (strncmp(buf, "md_", 3) != 0)
            return -EINVAL;
      return md_alloc(0, buf);
}

static void md_safemode_timeout(unsigned long data)
{
      mddev_t *mddev = (mddev_t *) data;

      if (!atomic_read(&mddev->writes_pending)) {
            mddev->safemode = 1;
            if (mddev->external)
                  sysfs_notify_dirent(mddev->sysfs_state);
      }
      md_wakeup_thread(mddev->thread);
}

static int start_dirty_degraded;

static int do_md_run(mddev_t * mddev)
{
      int err;
      mdk_rdev_t *rdev;
      struct gendisk *disk;
      struct mdk_personality *pers;

      if (list_empty(&mddev->disks))
            /* cannot run an array with no devices.. */
            return -EINVAL;

      if (mddev->pers)
            return -EBUSY;

      /*
       * Analyze all RAID superblock(s)
       */
      if (!mddev->raid_disks) {
            if (!mddev->persistent)
                  return -EINVAL;
            analyze_sbs(mddev);
      }

      if (mddev->level != LEVEL_NONE)
            request_module("md-level-%d", mddev->level);
      else if (mddev->clevel[0])
            request_module("md-%s", mddev->clevel);

      /*
       * Drop all container device buffers, from now on
       * the only valid external interface is through the md
       * device.
       */
      list_for_each_entry(rdev, &mddev->disks, same_set) {
            if (test_bit(Faulty, &rdev->flags))
                  continue;
            sync_blockdev(rdev->bdev);
            invalidate_bdev(rdev->bdev);

            /* perform some consistency tests on the device.
             * We don't want the data to overlap the metadata,
             * Internal Bitmap issues have been handled elsewhere.
             */
            if (rdev->data_offset < rdev->sb_start) {
                  if (mddev->dev_sectors &&
                      rdev->data_offset + mddev->dev_sectors
                      > rdev->sb_start) {
                        printk("md: %s: data overlaps metadata\n",
                               mdname(mddev));
                        return -EINVAL;
                  }
            } else {
                  if (rdev->sb_start + rdev->sb_size/512
                      > rdev->data_offset) {
                        printk("md: %s: metadata overlaps data\n",
                               mdname(mddev));
                        return -EINVAL;
                  }
            }
            sysfs_notify_dirent(rdev->sysfs_state);
      }

      md_probe(mddev->unit, NULL, NULL);
      disk = mddev->gendisk;
      if (!disk)
            return -ENOMEM;

      spin_lock(&pers_lock);
      pers = find_pers(mddev->level, mddev->clevel);
      if (!pers || !try_module_get(pers->owner)) {
            spin_unlock(&pers_lock);
            if (mddev->level != LEVEL_NONE)
                  printk(KERN_WARNING "md: personality for level %d is not loaded!\n",
                         mddev->level);
            else
                  printk(KERN_WARNING "md: personality for level %s is not loaded!\n",
                         mddev->clevel);
            return -EINVAL;
      }
      mddev->pers = pers;
      spin_unlock(&pers_lock);
      if (mddev->level != pers->level) {
            mddev->level = pers->level;
            mddev->new_level = pers->level;
      }
      strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));

      if (mddev->reshape_position != MaxSector &&
          pers->start_reshape == NULL) {
            /* This personality cannot handle reshaping... */
            mddev->pers = NULL;
            module_put(pers->owner);
            return -EINVAL;
      }

      if (pers->sync_request) {
            /* Warn if this is a potentially silly
             * configuration.
             */
            char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
            mdk_rdev_t *rdev2;
            int warned = 0;

            list_for_each_entry(rdev, &mddev->disks, same_set)
                  list_for_each_entry(rdev2, &mddev->disks, same_set) {
                        if (rdev < rdev2 &&
                            rdev->bdev->bd_contains ==
                            rdev2->bdev->bd_contains) {
                              printk(KERN_WARNING
                                     "%s: WARNING: %s appears to be"
                                     " on the same physical disk as"
                                     " %s.\n",
                                     mdname(mddev),
                                     bdevname(rdev->bdev,b),
                                     bdevname(rdev2->bdev,b2));
                              warned = 1;
                        }
                  }

            if (warned)
                  printk(KERN_WARNING
                         "True protection against single-disk"
                         " failure might be compromised.\n");
      }

      mddev->recovery = 0;
      /* may be over-ridden by personality */
      mddev->resync_max_sectors = mddev->dev_sectors;

      mddev->barriers_work = 1;
      mddev->ok_start_degraded = start_dirty_degraded;

      if (start_readonly)
            mddev->ro = 2; /* read-only, but switch on first write */

      err = mddev->pers->run(mddev);
      if (err)
            printk(KERN_ERR "md: pers->run() failed ...\n");
      else if (mddev->pers->size(mddev, 0, 0) < mddev->array_sectors) {
            WARN_ONCE(!mddev->external_size, "%s: default size too small,"
                    " but 'external_size' not in effect?\n", __func__);
            printk(KERN_ERR
                   "md: invalid array_size %llu > default size %llu\n",
                   (unsigned long long)mddev->array_sectors / 2,
                   (unsigned long long)mddev->pers->size(mddev, 0, 0) / 2);
            err = -EINVAL;
            mddev->pers->stop(mddev);
      }
      if (err == 0 && mddev->pers->sync_request) {
            err = bitmap_create(mddev);
            if (err) {
                  printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
                         mdname(mddev), err);
                  mddev->pers->stop(mddev);
            }
      }
      if (err) {
            module_put(mddev->pers->owner);
            mddev->pers = NULL;
            bitmap_destroy(mddev);
            return err;
      }
      if (mddev->pers->sync_request) {
            if (sysfs_create_group(&mddev->kobj, &md_redundancy_group))
                  printk(KERN_WARNING
                         "md: cannot register extra attributes for %s\n",
                         mdname(mddev));
            mddev->sysfs_action = sysfs_get_dirent(mddev->kobj.sd, "sync_action");
      } else if (mddev->ro == 2) /* auto-readonly not meaningful */
            mddev->ro = 0;

      atomic_set(&mddev->writes_pending,0);
      mddev->safemode = 0;
      mddev->safemode_timer.function = md_safemode_timeout;
      mddev->safemode_timer.data = (unsigned long) mddev;
      mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
      mddev->in_sync = 1;

      list_for_each_entry(rdev, &mddev->disks, same_set)
            if (rdev->raid_disk >= 0) {
                  char nm[20];
                  sprintf(nm, "rd%d", rdev->raid_disk);
                  if (sysfs_create_link(&mddev->kobj, &rdev->kobj, nm))
                        printk("md: cannot register %s for %s\n",
                               nm, mdname(mddev));
            }
      
      set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
      
      if (mddev->flags)
            md_update_sb(mddev, 0);

      set_capacity(disk, mddev->array_sectors);

      /* If there is a partially-recovered drive we need to
       * start recovery here.  If we leave it to md_check_recovery,
       * it will remove the drives and not do the right thing
       */
      if (mddev->degraded && !mddev->sync_thread) {
            int spares = 0;
            list_for_each_entry(rdev, &mddev->disks, same_set)
                  if (rdev->raid_disk >= 0 &&
                      !test_bit(In_sync, &rdev->flags) &&
                      !test_bit(Faulty, &rdev->flags))
                        /* complete an interrupted recovery */
                        spares++;
            if (spares && mddev->pers->sync_request) {
                  mddev->recovery = 0;
                  set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
                  mddev->sync_thread = md_register_thread(md_do_sync,
                                                mddev,
                                                "%s_resync");
                  if (!mddev->sync_thread) {
                        printk(KERN_ERR "%s: could not start resync"
                               " thread...\n",
                               mdname(mddev));
                        /* leave the spares where they are, it shouldn't hurt */
                        mddev->recovery = 0;
                  }
            }
      }
      md_wakeup_thread(mddev->thread);
      md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */

      revalidate_disk(mddev->gendisk);
      mddev->changed = 1;
      md_new_event(mddev);
      sysfs_notify_dirent(mddev->sysfs_state);
      if (mddev->sysfs_action)
            sysfs_notify_dirent(mddev->sysfs_action);
      sysfs_notify(&mddev->kobj, NULL, "degraded");
      kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
      return 0;
}

static int restart_array(mddev_t *mddev)
{
      struct gendisk *disk = mddev->gendisk;

      /* Complain if it has no devices */
      if (list_empty(&mddev->disks))
            return -ENXIO;
      if (!mddev->pers)
            return -EINVAL;
      if (!mddev->ro)
            return -EBUSY;
      mddev->safemode = 0;
      mddev->ro = 0;
      set_disk_ro(disk, 0);
      printk(KERN_INFO "md: %s switched to read-write mode.\n",
            mdname(mddev));
      /* Kick recovery or resync if necessary */
      set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
      md_wakeup_thread(mddev->thread);
      md_wakeup_thread(mddev->sync_thread);
      sysfs_notify_dirent(mddev->sysfs_state);
      return 0;
}

/* similar to deny_write_access, but accounts for our holding a reference
 * to the file ourselves */
static int deny_bitmap_write_access(struct file * file)
{
      struct inode *inode = file->f_mapping->host;

      spin_lock(&inode->i_lock);
      if (atomic_read(&inode->i_writecount) > 1) {
            spin_unlock(&inode->i_lock);
            return -ETXTBSY;
      }
      atomic_set(&inode->i_writecount, -1);
      spin_unlock(&inode->i_lock);

      return 0;
}

static void restore_bitmap_write_access(struct file *file)
{
      struct inode *inode = file->f_mapping->host;

      spin_lock(&inode->i_lock);
      atomic_set(&inode->i_writecount, 1);
      spin_unlock(&inode->i_lock);
}

/* mode:
 *   0 - completely stop and dis-assemble array
 *   1 - switch to readonly
 *   2 - stop but do not disassemble array
 */
static int do_md_stop(mddev_t * mddev, int mode, int is_open)
{
      int err = 0;
      struct gendisk *disk = mddev->gendisk;
      mdk_rdev_t *rdev;

      mutex_lock(&mddev->open_mutex);
      if (atomic_read(&mddev->openers) > is_open) {
            printk("md: %s still in use.\n",mdname(mddev));
            err = -EBUSY;
      } else if (mddev->pers) {

            if (mddev->sync_thread) {
                  set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
                  set_bit(MD_RECOVERY_INTR, &mddev->recovery);
                  md_unregister_thread(mddev->sync_thread);
                  mddev->sync_thread = NULL;
            }

            del_timer_sync(&mddev->safemode_timer);

            switch(mode) {
            case 1: /* readonly */
                  err  = -ENXIO;
                  if (mddev->ro==1)
                        goto out;
                  mddev->ro = 1;
                  break;
            case 0: /* disassemble */
            case 2: /* stop */
                  bitmap_flush(mddev);
                  md_super_wait(mddev);
                  if (mddev->ro)
                        set_disk_ro(disk, 0);

                  mddev->pers->stop(mddev);
                  mddev->queue->merge_bvec_fn = NULL;
                  mddev->queue->unplug_fn = NULL;
                  mddev->queue->backing_dev_info.congested_fn = NULL;
                  module_put(mddev->pers->owner);
                  if (mddev->pers->sync_request)
                        mddev->private = &md_redundancy_group;
                  mddev->pers = NULL;
                  /* tell userspace to handle 'inactive' */
                  sysfs_notify_dirent(mddev->sysfs_state);

                  list_for_each_entry(rdev, &mddev->disks, same_set)
                        if (rdev->raid_disk >= 0) {
                              char nm[20];
                              sprintf(nm, "rd%d", rdev->raid_disk);
                              sysfs_remove_link(&mddev->kobj, nm);
                        }

                  set_capacity(disk, 0);
                  mddev->changed = 1;

                  if (mddev->ro)
                        mddev->ro = 0;
            }
            if (!mddev->in_sync || mddev->flags) {
                  /* mark array as shutdown cleanly */
                  mddev->in_sync = 1;
                  md_update_sb(mddev, 1);
            }
            if (mode == 1)
                  set_disk_ro(disk, 1);
            clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
            err = 0;
      }
out:
      mutex_unlock(&mddev->open_mutex);
      if (err)
            return err;
      /*
       * Free resources if final stop
       */
      if (mode == 0) {

            printk(KERN_INFO "md: %s stopped.\n", mdname(mddev));

            bitmap_destroy(mddev);
            if (mddev->bitmap_file) {
                  restore_bitmap_write_access(mddev->bitmap_file);
                  fput(mddev->bitmap_file);
                  mddev->bitmap_file = NULL;
            }
            mddev->bitmap_offset = 0;

            /* make sure all md_delayed_delete calls have finished */
            flush_scheduled_work();

            export_array(mddev);

            mddev->array_sectors = 0;
            mddev->external_size = 0;
            mddev->dev_sectors = 0;
            mddev->raid_disks = 0;
            mddev->recovery_cp = 0;
            mddev->resync_min = 0;
            mddev->resync_max = MaxSector;
            mddev->reshape_position = MaxSector;
            mddev->external = 0;
            mddev->persistent = 0;
            mddev->level = LEVEL_NONE;
            mddev->clevel[0] = 0;
            mddev->flags = 0;
            mddev->ro = 0;
            mddev->metadata_type[0] = 0;
            mddev->chunk_sectors = 0;
            mddev->ctime = mddev->utime = 0;
            mddev->layout = 0;
            mddev->max_disks = 0;
            mddev->events = 0;
            mddev->delta_disks = 0;
            mddev->new_level = LEVEL_NONE;
            mddev->new_layout = 0;
            mddev->new_chunk_sectors = 0;
            mddev->curr_resync = 0;
            mddev->resync_mismatches = 0;
            mddev->suspend_lo = mddev->suspend_hi = 0;
            mddev->sync_speed_min = mddev->sync_speed_max = 0;
            mddev->recovery = 0;
            mddev->in_sync = 0;
            mddev->changed = 0;
            mddev->degraded = 0;
            mddev->barriers_work = 0;
            mddev->safemode = 0;
            kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
            if (mddev->hold_active == UNTIL_STOP)
                  mddev->hold_active = 0;

      } else if (mddev->pers)
            printk(KERN_INFO "md: %s switched to read-only mode.\n",
                  mdname(mddev));
      err = 0;
      blk_integrity_unregister(disk);
      md_new_event(mddev);
      sysfs_notify_dirent(mddev->sysfs_state);
      return err;
}

#ifndef MODULE
static void autorun_array(mddev_t *mddev)
{
      mdk_rdev_t *rdev;
      int err;

      if (list_empty(&mddev->disks))
            return;

      printk(KERN_INFO "md: running: ");

      list_for_each_entry(rdev, &mddev->disks, same_set) {
            char b[BDEVNAME_SIZE];
            printk("<%s>", bdevname(rdev->bdev,b));
      }
      printk("\n");

      err = do_md_run(mddev);
      if (err) {
            printk(KERN_WARNING "md: do_md_run() returned %d\n", err);
            do_md_stop(mddev, 0, 0);
      }
}

/*
 * lets try to run arrays based on all disks that have arrived
 * until now. (those are in pending_raid_disks)
 *
 * the method: pick the first pending disk, collect all disks with
 * the same UUID, remove all from the pending list and put them into
 * the 'same_array' list. Then order this list based on superblock
 * update time (freshest comes first), kick out 'old' disks and
 * compare superblocks. If everything's fine then run it.
 *
 * If "unit" is allocated, then bump its reference count
 */
static void autorun_devices(int part)
{
      mdk_rdev_t *rdev0, *rdev, *tmp;
      mddev_t *mddev;
      char b[BDEVNAME_SIZE];

      printk(KERN_INFO "md: autorun ...\n");
      while (!list_empty(&pending_raid_disks)) {
            int unit;
            dev_t dev;
            LIST_HEAD(candidates);
            rdev0 = list_entry(pending_raid_disks.next,
                               mdk_rdev_t, same_set);

            printk(KERN_INFO "md: considering %s ...\n",
                  bdevname(rdev0->bdev,b));
            INIT_LIST_HEAD(&candidates);
            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));
                        list_move(&rdev->same_set, &candidates);
                  }
            /*
             * now we have a set of devices, with all of them having
             * mostly sane superblocks. It's time to allocate the
             * mddev.
             */
            if (part) {
                  dev = MKDEV(mdp_major,
                            rdev0->preferred_minor << MdpMinorShift);
                  unit = MINOR(dev) >> MdpMinorShift;
            } else {
                  dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
                  unit = MINOR(dev);
            }
            if (rdev0->preferred_minor != unit) {
                  printk(KERN_INFO "md: unit number in %s is bad: %d\n",
                         bdevname(rdev0->bdev, b), rdev0->preferred_minor);
                  break;
            }

            md_probe(dev, NULL, NULL);
            mddev = mddev_find(dev);
            if (!mddev || !mddev->gendisk) {
                  if (mddev)
                        mddev_put(mddev);
                  printk(KERN_ERR
                        "md: cannot allocate memory for md drive.\n");
                  break;
            }
            if (mddev_lock(mddev)) 
                  printk(KERN_WARNING "md: %s locked, cannot run\n",
                         mdname(mddev));
            else if (mddev->raid_disks || mddev->major_version
                   || !list_empty(&mddev->disks)) {
                  printk(KERN_WARNING 
                        "md: %s already running, cannot run %s\n",
                        mdname(mddev), bdevname(rdev0->bdev,b));
                  mddev_unlock(mddev);
            } else {
                  printk(KERN_INFO "md: created %s\n", mdname(mddev));
                  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);
                  }
                  autorun_array(mddev);
                  mddev_unlock(mddev);
            }
            /* on success, candidates will be empty, on error
             * it won't...
             */
            rdev_for_each_list(rdev, tmp, &candidates) {
                  list_del_init(&rdev->same_set);
                  export_rdev(rdev);
            }
            mddev_put(mddev);
      }
      printk(KERN_INFO "md: ... autorun DONE.\n");
}
#endif /* !MODULE */

static int get_version(void __user * arg)
{
      mdu_version_t ver;

      ver.major = MD_MAJOR_VERSION;
      ver.minor = MD_MINOR_VERSION;
      ver.patchlevel = MD_PATCHLEVEL_VERSION;

      if (copy_to_user(arg, &ver, sizeof(ver)))
            return -EFAULT;

      return 0;
}

static int get_array_info(mddev_t * mddev, void __user * arg)
{
      mdu_array_info_t info;
      int nr,working,active,failed,spare;
      mdk_rdev_t *rdev;

      nr=working=active=failed=spare=0;
      list_for_each_entry(rdev, &mddev->disks, same_set) {
            nr++;
            if (test_bit(Faulty, &rdev->flags))
                  failed++;
            else {
                  working++;
                  if (test_bit(In_sync, &rdev->flags))
                        active++;   
                  else
                        spare++;
            }
      }

      info.major_version = mddev->major_version;
      info.minor_version = mddev->minor_version;
      info.patch_version = MD_PATCHLEVEL_VERSION;
      info.ctime         = mddev->ctime;
      info.level         = mddev->level;
      info.size          = mddev->dev_sectors / 2;
      if (info.size != mddev->dev_sectors / 2) /* overflow */
            info.size = -1;
      info.nr_disks      = nr;
      info.raid_disks    = mddev->raid_disks;
      info.md_minor      = mddev->md_minor;
      info.not_persistent= !mddev->persistent;

      info.utime         = mddev->utime;
      info.state         = 0;
      if (mddev->in_sync)
            info.state = (1<<MD_SB_CLEAN);
      if (mddev->bitmap && mddev->bitmap_offset)
            info.state = (1<<MD_SB_BITMAP_PRESENT);
      info.active_disks  = active;
      info.working_disks = working;
      info.failed_disks  = failed;
      info.spare_disks   = spare;

      info.layout        = mddev->layout;
      info.chunk_size    = mddev->chunk_sectors << 9;

      if (copy_to_user(arg, &info, sizeof(info)))
            return -EFAULT;

      return 0;
}

static int get_bitmap_file(mddev_t * mddev, void __user * arg)
{
      mdu_bitmap_file_t *file = NULL; /* too big for stack allocation */
      char *ptr, *buf = NULL;
      int err = -ENOMEM;

      if (md_allow_write(mddev))
            file = kmalloc(sizeof(*file), GFP_NOIO);
      else
            file = kmalloc(sizeof(*file), GFP_KERNEL);

      if (!file)
            goto out;

      /* bitmap disabled, zero the first byte and copy out */
      if (!mddev->bitmap || !mddev->bitmap->file) {
            file->pathname[0] = '\0';
            goto copy_out;
      }

      buf = kmalloc(sizeof(file->pathname), GFP_KERNEL);
      if (!buf)
            goto out;

      ptr = d_path(&mddev->bitmap->file->f_path, buf, sizeof(file->pathname));
      if (IS_ERR(ptr))
            goto out;

      strcpy(file->pathname, ptr);

copy_out:
      err = 0;
      if (copy_to_user(arg, file, sizeof(*file)))
            err = -EFAULT;
out:
      kfree(buf);
      kfree(file);
      return err;
}

static int get_disk_info(mddev_t * mddev, void __user * arg)
{
      mdu_disk_info_t info;
      mdk_rdev_t *rdev;

      if (copy_from_user(&info, arg, sizeof(info)))
            return -EFAULT;

      rdev = find_rdev_nr(mddev, info.number);
      if (rdev) {
            info.major = MAJOR(rdev->bdev->bd_dev);
            info.minor = MINOR(rdev->bdev->bd_dev);
            info.raid_disk = rdev->raid_disk;
            info.state = 0;
            if (test_bit(Faulty, &rdev->flags))
                  info.state |= (1<<MD_DISK_FAULTY);
            else if (test_bit(In_sync, &rdev->flags)) {
                  info.state |= (1<<MD_DISK_ACTIVE);
                  info.state |= (1<<MD_DISK_SYNC);
            }
            if (test_bit(WriteMostly, &rdev->flags))
                  info.state |= (1<<MD_DISK_WRITEMOSTLY);
      } else {
            info.major = info.minor = 0;
            info.raid_disk = -1;
            info.state = (1<<MD_DISK_REMOVED);
      }

      if (copy_to_user(arg, &info, sizeof(info)))
            return -EFAULT;

      return 0;
}

static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
{
      char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
      mdk_rdev_t *rdev;
      dev_t dev = MKDEV(info->major,info->minor);

      if (info->major != MAJOR(dev) || info->minor != MINOR(dev))
            return -EOVERFLOW;

      if (!mddev->raid_disks) {
            int err;
            /* expecting a device which has a superblock */
            rdev = md_import_device(dev, mddev->major_version, mddev->minor_version);
            if (IS_ERR(rdev)) {
                  printk(KERN_WARNING 
                        "md: md_import_device returned %ld\n",
                        PTR_ERR(rdev));
                  return PTR_ERR(rdev);
            }
            if (!list_empty(&mddev->disks)) {
                  mdk_rdev_t *rdev0 = list_entry(mddev->disks.next,
                                          mdk_rdev_t, same_set);
                  int err = super_types[mddev->major_version]
                        .load_super(rdev, rdev0, mddev->minor_version);
                  if (err < 0) {
                        printk(KERN_WARNING 
                              "md: %s has different UUID to %s\n",
                              bdevname(rdev->bdev,b), 
                              bdevname(rdev0->bdev,b2));
                        export_rdev(rdev);
                        return -EINVAL;
                  }
            }
            err = bind_rdev_to_array(rdev, mddev);
            if (err)
                  export_rdev(rdev);
            return err;
      }

      /*
       * add_new_disk can be used once the array is assembled
       * to add "hot spares".  They must already have a superblock
       * written
       */
      if (mddev->pers) {
            int err;
            if (!mddev->pers->hot_add_disk) {
                  printk(KERN_WARNING 
                        "%s: personality does not support diskops!\n",
                         mdname(mddev));
                  return -EINVAL;
            }
            if (mddev->persistent)
                  rdev = md_import_device(dev, mddev->major_version,
                                    mddev->minor_version);
            else
                  rdev = md_import_device(dev, -1, -1);
            if (IS_ERR(rdev)) {
                  printk(KERN_WARNING 
                        "md: md_import_device returned %ld\n",
                        PTR_ERR(rdev));
                  return PTR_ERR(rdev);
            }
            /* set save_raid_disk if appropriate */
            if (!mddev->persistent) {
                  if (info->state & (1<<MD_DISK_SYNC)  &&
                      info->raid_disk < mddev->raid_disks)
                        rdev->raid_disk = info->raid_disk;
                  else
                        rdev->raid_disk = -1;
            } else
                  super_types[mddev->major_version].
                        validate_super(mddev, rdev);
            rdev->saved_raid_disk = rdev->raid_disk;

            clear_bit(In_sync, &rdev->flags); /* just to be sure */
            if (info->state & (1<<MD_DISK_WRITEMOSTLY))
                  set_bit(WriteMostly, &rdev->flags);
            else
                  clear_bit(WriteMostly, &rdev->flags);

            rdev->raid_disk = -1;
            err = bind_rdev_to_array(rdev, mddev);
            if (!err && !mddev->pers->hot_remove_disk) {
                  /* If there is hot_add_disk but no hot_remove_disk
                   * then added disks for geometry changes,
                   * and should be added immediately.
                   */
                  super_types[mddev->major_version].
                        validate_super(mddev, rdev);
                  err = mddev->pers->hot_add_disk(mddev, rdev);
                  if (err)
                        unbind_rdev_from_array(rdev);
            }
            if (err)
                  export_rdev(rdev);
            else
                  sysfs_notify_dirent(rdev->sysfs_state);

            md_update_sb(mddev, 1);
            if (mddev->degraded)
                  set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
            set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
            md_wakeup_thread(mddev->thread);
            return err;
      }

      /* otherwise, add_new_disk is only allowed
       * for major_version==0 superblocks
       */
      if (mddev->major_version != 0) {
            printk(KERN_WARNING "%s: ADD_NEW_DISK not supported\n",
                   mdname(mddev));
            return -EINVAL;
      }

      if (!(info->state & (1<<MD_DISK_FAULTY))) {
            int err;
            rdev = md_import_device(dev, -1, 0);
            if (IS_ERR(rdev)) {
                  printk(KERN_WARNING 
                        "md: error, md_import_device() returned %ld\n",
                        PTR_ERR(rdev));
                  return PTR_ERR(rdev);
            }
            rdev->desc_nr = info->number;
            if (info->raid_disk < mddev->raid_disks)
                  rdev->raid_disk = info->raid_disk;
            else
                  rdev->raid_disk = -1;

            if (rdev->raid_disk < mddev->raid_disks)
                  if (info->state & (1<<MD_DISK_SYNC))
                        set_bit(In_sync, &rdev->flags);

            if (info->state & (1<<MD_DISK_WRITEMOSTLY))
                  set_bit(WriteMostly, &rdev->flags);

            if (!mddev->persistent) {
                  printk(KERN_INFO "md: nonpersistent superblock ...\n");
                  rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
            } else 
                  rdev->sb_start = calc_dev_sboffset(rdev->bdev);
            rdev->sectors = rdev->sb_start;

            err = bind_rdev_to_array(rdev, mddev);
            if (err) {
                  export_rdev(rdev);
                  return err;
            }
      }

      return 0;
}

static int hot_remove_disk(mddev_t * mddev, dev_t dev)
{
      char b[BDEVNAME_SIZE];
      mdk_rdev_t *rdev;

      rdev = find_rdev(mddev, dev);
      if (!rdev)
            return -ENXIO;

      if (rdev->raid_disk >= 0)
            goto busy;

      kick_rdev_from_array(rdev);
      md_update_sb(mddev, 1);
      md_new_event(mddev);

      return 0;
busy:
      printk(KERN_WARNING "md: cannot remove active disk %s from %s ...\n",
            bdevname(rdev->bdev,b), mdname(mddev));
      return -EBUSY;
}

static int hot_add_disk(mddev_t * mddev, dev_t dev)
{
      char b[BDEVNAME_SIZE];
      int err;
      mdk_rdev_t *rdev;

      if (!mddev->pers)
            return -ENODEV;

      if (mddev->major_version != 0) {
            printk(KERN_WARNING "%s: HOT_ADD may only be used with"
                  " version-0 superblocks.\n",
                  mdname(mddev));
            return -EINVAL;
      }
      if (!mddev->pers->hot_add_disk) {
            printk(KERN_WARNING 
                  "%s: personality does not support diskops!\n",
                  mdname(mddev));
            return -EINVAL;
      }

      rdev = md_import_device(dev, -1, 0);
      if (IS_ERR(rdev)) {
            printk(KERN_WARNING 
                  "md: error, md_import_device() returned %ld\n",
                  PTR_ERR(rdev));
            return -EINVAL;
      }

      if (mddev->persistent)
            rdev->sb_start = calc_dev_sboffset(rdev->bdev);
      else
            rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;

      rdev->sectors = rdev->sb_start;

      if (test_bit(Faulty, &rdev->flags)) {
            printk(KERN_WARNING 
                  "md: can not hot-add faulty %s disk to %s!\n",
                  bdevname(rdev->bdev,b), mdname(mddev));
            err = -EINVAL;
            goto abort_export;
      }
      clear_bit(In_sync, &rdev->flags);
      rdev->desc_nr = -1;
      rdev->saved_raid_disk = -1;
      err = bind_rdev_to_array(rdev, mddev);
      if (err)
            goto abort_export;

      /*
       * The rest should better be atomic, we can have disk failures
       * noticed in interrupt contexts ...
       */

      rdev->raid_disk = -1;

      md_update_sb(mddev, 1);

      /*
       * Kick recovery, maybe this spare has to be added to the
       * array immediately.
       */
      set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
      md_wakeup_thread(mddev->thread);
      md_new_event(mddev);
      return 0;

abort_export:
      export_rdev(rdev);
      return err;
}

static int set_bitmap_file(mddev_t *mddev, int fd)
{
      int err;

      if (mddev->pers) {
            if (!mddev->pers->quiesce)
                  return -EBUSY;
            if (mddev->recovery || mddev->sync_thread)
                  return -EBUSY;
            /* we should be able to change the bitmap.. */
      }


      if (fd >= 0) {
            if (mddev->bitmap)
                  return -EEXIST; /* cannot add when bitmap is present */
            mddev->bitmap_file = fget(fd);

            if (mddev->bitmap_file == NULL) {
                  printk(KERN_ERR "%s: error: failed to get bitmap file\n",
                         mdname(mddev));
                  return -EBADF;
            }

            err = deny_bitmap_write_access(mddev->bitmap_file);
            if (err) {
                  printk(KERN_ERR "%s: error: bitmap file is already in use\n",
                         mdname(mddev));
                  fput(mddev->bitmap_file);
                  mddev->bitmap_file = NULL;
                  return err;
            }
            mddev->bitmap_offset = 0; /* file overrides offset */
      } else if (mddev->bitmap == NULL)
            return -ENOENT; /* cannot remove what isn't there */
      err = 0;
      if (mddev->pers) {
            mddev->pers->quiesce(mddev, 1);
            if (fd >= 0)
                  err = bitmap_create(mddev);
            if (fd < 0 || err) {
                  bitmap_destroy(mddev);
                  fd = -1; /* make sure to put the file */
            }
            mddev->pers->quiesce(mddev, 0);
      }
      if (fd < 0) {
            if (mddev->bitmap_file) {
                  restore_bitmap_write_access(mddev->bitmap_file);
                  fput(mddev->bitmap_file);
            }
            mddev->bitmap_file = NULL;
      }

      return err;
}

/*
 * set_array_info is used two different ways
 * The original usage is when creating a new array.
 * In this usage, raid_disks is > 0 and it together with
 *  level, size, not_persistent,layout,chunksize determine the
 *  shape of the array.
 *  This will always create an array with a type-0.90.0 superblock.
 * The newer usage is when assembling an array.
 *  In this case raid_disks will be 0, and the major_version field is
 *  use to determine which style super-blocks are to be found on the devices.
 *  The minor and patch _version numbers are also kept incase the
 *  super_block handler wishes to interpret them.
 */
static int set_array_info(mddev_t * mddev, mdu_array_info_t *info)
{

      if (info->raid_disks == 0) {
            /* just setting version number for superblock loading */
            if (info->major_version < 0 ||
                info->major_version >= ARRAY_SIZE(super_types) ||
                super_types[info->major_version].name == NULL) {
                  /* maybe try to auto-load a module? */
                  printk(KERN_INFO 
                        "md: superblock version %d not known\n",
                        info->major_version);
                  return -EINVAL;
            }
            mddev->major_version = info->major_version;
            mddev->minor_version = info->minor_version;
            mddev->patch_version = info->patch_version;
            mddev->persistent = !info->not_persistent;
            return 0;
      }
      mddev->major_version = MD_MAJOR_VERSION;
      mddev->minor_version = MD_MINOR_VERSION;
      mddev->patch_version = MD_PATCHLEVEL_VERSION;
      mddev->ctime         = get_seconds();

      mddev->level         = info->level;
      mddev->clevel[0]     = 0;
      mddev->dev_sectors   = 2 * (sector_t)info->size;
      mddev->raid_disks    = info->raid_disks;
      /* don't set md_minor, it is determined by which /dev/md* was
       * openned
       */
      if (info->state & (1<<MD_SB_CLEAN))
            mddev->recovery_cp = MaxSector;
      else
            mddev->recovery_cp = 0;
      mddev->persistent    = ! info->not_persistent;
      mddev->external        = 0;

      mddev->layout        = info->layout;
      mddev->chunk_sectors = info->chunk_size >> 9;

      mddev->max_disks     = MD_SB_DISKS;

      if (mddev->persistent)
            mddev->flags         = 0;
      set_bit(MD_CHANGE_DEVS, &mddev->flags);

      mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
      mddev->bitmap_offset = 0;

      mddev->reshape_position = MaxSector;

      /*
       * Generate a 128 bit UUID
       */
      get_random_bytes(mddev->uuid, 16);

      mddev->new_level = mddev->level;
      mddev->new_chunk_sectors = mddev->chunk_sectors;
      mddev->new_layout = mddev->layout;
      mddev->delta_disks = 0;

      return 0;
}

void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors)
{
      WARN(!mddev_is_locked(mddev), "%s: unlocked mddev!\n", __func__);

      if (mddev->external_size)
            return;

      mddev->array_sectors = array_sectors;
}
EXPORT_SYMBOL(md_set_array_sectors);

static int update_size(mddev_t *mddev, sector_t num_sectors)
{
      mdk_rdev_t *rdev;
      int rv;
      int fit = (num_sectors == 0);

      if (mddev->pers->resize == NULL)
            return -EINVAL;
      /* The "num_sectors" is the number of sectors of each device that
       * is used.  This can only make sense for arrays with redundancy.
       * linear and raid0 always use whatever space is available. We can only
       * consider changing this number if no resync or reconstruction is
       * happening, and if the new size is acceptable. It must fit before the
       * sb_start or, if that is <data_offset, it must fit before the size
       * of each device.  If num_sectors is zero, we find the largest size
       * that fits.

       */
      if (mddev->sync_thread)
            return -EBUSY;
      if (mddev->bitmap)
            /* Sorry, cannot grow a bitmap yet, just remove it,
             * grow, and re-add.
             */
            return -EBUSY;
      list_for_each_entry(rdev, &mddev->disks, same_set) {
            sector_t avail = rdev->sectors;

            if (fit && (num_sectors == 0 || num_sectors > avail))
                  num_sectors = avail;
            if (avail < num_sectors)
                  return -ENOSPC;
      }
      rv = mddev->pers->resize(mddev, num_sectors);
      if (!rv)
            revalidate_disk(mddev->gendisk);
      return rv;
}

static int update_raid_disks(mddev_t *mddev, int raid_disks)
{
      int rv;
      /* change the number of raid disks */
      if (mddev->pers->check_reshape == NULL)
            return -EINVAL;
      if (raid_disks <= 0 ||
          raid_disks >= mddev->max_disks)
            return -EINVAL;
      if (mddev->sync_thread || mddev->reshape_position != MaxSector)
            return -EBUSY;
      mddev->delta_disks = raid_disks - mddev->raid_disks;

      rv = mddev->pers->check_reshape(mddev);
      return rv;
}


/*
 * update_array_info is used to change the configuration of an
 * on-line array.
 * The version, ctime,level,size,raid_disks,not_persistent, layout,chunk_size
 * fields in the info are checked against the array.
 * Any differences that cannot be handled will cause an error.
 * Normally, only one change can be managed at a time.
 */
static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
{
      int rv = 0;
      int cnt = 0;
      int state = 0;

      /* calculate expected state,ignoring low bits */
      if (mddev->bitmap && mddev->bitmap_offset)
            state |= (1 << MD_SB_BITMAP_PRESENT);

      if (mddev->major_version != info->major_version ||
          mddev->minor_version != info->minor_version ||
/*        mddev->patch_version != info->patch_version || */
          mddev->ctime         != info->ctime         ||
          mddev->level         != info->level         ||
/*        mddev->layout        != info->layout        || */
          !mddev->persistent   != info->not_persistent||
          mddev->chunk_sectors != info->chunk_size >> 9 ||
          /* ignore bottom 8 bits of state, and allow SB_BITMAP_PRESENT to change */
          ((state^info->state) & 0xfffffe00)
            )
            return -EINVAL;
      /* Check there is only one change */
      if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
            cnt++;
      if (mddev->raid_disks != info->raid_disks)
            cnt++;
      if (mddev->layout != info->layout)
            cnt++;
      if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT))
            cnt++;
      if (cnt == 0)
            return 0;
      if (cnt > 1)
            return -EINVAL;

      if (mddev->layout != info->layout) {
            /* Change layout
             * we don't need to do anything at the md level, the
             * personality will take care of it all.
             */
            if (mddev->pers->check_reshape == NULL)
                  return -EINVAL;
            else {
                  mddev->new_layout = info->layout;
                  rv = mddev->pers->check_reshape(mddev);
                  if (rv)
                        mddev->new_layout = mddev->layout;
                  return rv;
            }
      }
      if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
            rv = update_size(mddev, (sector_t)info->size * 2);

      if (mddev->raid_disks    != info->raid_disks)
            rv = update_raid_disks(mddev, info->raid_disks);

      if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) {
            if (mddev->pers->quiesce == NULL)
                  return -EINVAL;
            if (mddev->recovery || mddev->sync_thread)
                  return -EBUSY;
            if (info->state & (1<<MD_SB_BITMAP_PRESENT)) {
                  /* add the bitmap */
                  if (mddev->bitmap)
                        return -EEXIST;
                  if (mddev->default_bitmap_offset == 0)
                        return -EINVAL;
                  mddev->bitmap_offset = mddev->default_bitmap_offset;
                  mddev->pers->quiesce(mddev, 1);
                  rv = bitmap_create(mddev);
                  if (rv)
                        bitmap_destroy(mddev);
                  mddev->pers->quiesce(mddev, 0);
            } else {
                  /* remove the bitmap */
                  if (!mddev->bitmap)
                        return -ENOENT;
                  if (mddev->bitmap->file)
                        return -EINVAL;
                  mddev->pers->quiesce(mddev, 1);
                  bitmap_destroy(mddev);
                  mddev->pers->quiesce(mddev, 0);
                  mddev->bitmap_offset = 0;
            }
      }
      md_update_sb(mddev, 1);
      return rv;
}

static int set_disk_faulty(mddev_t *mddev, dev_t dev)
{
      mdk_rdev_t *rdev;

      if (mddev->pers == NULL)
            return -ENODEV;

      rdev = find_rdev(mddev, dev);
      if (!rdev)
            return -ENODEV;

      md_error(mddev, rdev);
      return 0;
}

/*
 * We have a problem here : there is no easy way to give a CHS
 * virtual geometry. We currently pretend that we have a 2 heads
 * 4 sectors (with a BIG number of cylinders...). This drives
 * dosfs just mad... ;-)
 */
static int md_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
      mddev_t *mddev = bdev->bd_disk->private_data;

      geo->heads = 2;
      geo->sectors = 4;
      geo->cylinders = get_capacity(mddev->gendisk) / 8;
      return 0;
}

static int md_ioctl(struct block_device *bdev, fmode_t mode,
                  unsigned int cmd, unsigned long arg)
{
      int err = 0;
      void __user *argp = (void __user *)arg;
      mddev_t *mddev = NULL;

      if (!capable(CAP_SYS_ADMIN))
            return -EACCES;

      /*
       * Commands dealing with the RAID driver but not any
       * particular array:
       */
      switch (cmd)
      {
            case RAID_VERSION:
                  err = get_version(argp);
                  goto done;

            case PRINT_RAID_DEBUG:
                  err = 0;
                  md_print_devices();
                  goto done;

#ifndef MODULE
            case RAID_AUTORUN:
                  err = 0;
                  autostart_arrays(arg);
                  goto done;
#endif
            default:;
      }

      /*
       * Commands creating/starting a new array:
       */

      mddev = bdev->bd_disk->private_data;

      if (!mddev) {
            BUG();
            goto abort;
      }

      err = mddev_lock(mddev);
      if (err) {
            printk(KERN_INFO 
                  "md: ioctl lock interrupted, reason %d, cmd %d\n",
                  err, cmd);
            goto abort;
      }

      switch (cmd)
      {
            case SET_ARRAY_INFO:
                  {
                        mdu_array_info_t info;
                        if (!arg)
                              memset(&info, 0, sizeof(info));
                        else if (copy_from_user(&info, argp, sizeof(info))) {
                              err = -EFAULT;
                              goto abort_unlock;
                        }
                        if (mddev->pers) {
                              err = update_array_info(mddev, &info);
                              if (err) {
                                    printk(KERN_WARNING "md: couldn't update"
                                           " array info. %d\n", err);
                                    goto abort_unlock;
                              }
                              goto done_unlock;
                        }
                        if (!list_empty(&mddev->disks)) {
                              printk(KERN_WARNING
                                     "md: array %s already has disks!\n",
                                     mdname(mddev));
                              err = -EBUSY;
                              goto abort_unlock;
                        }
                        if (mddev->raid_disks) {
                              printk(KERN_WARNING
                                     "md: array %s already initialised!\n",
                                     mdname(mddev));
                              err = -EBUSY;
                              goto abort_unlock;
                        }
                        err = set_array_info(mddev, &info);
                        if (err) {
                              printk(KERN_WARNING "md: couldn't set"
                                     " array info. %d\n", err);
                              goto abort_unlock;
                        }
                  }
                  goto done_unlock;

            default:;
      }

      /*
       * Commands querying/configuring an existing array:
       */
      /* 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 && !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;
      }

      /*
       * Commands even a read-only array can execute:
       */
      switch (cmd)
      {
            case GET_ARRAY_INFO:
                  err = get_array_info(mddev, argp);
                  goto done_unlock;

            case GET_BITMAP_FILE:
                  err = get_bitmap_file(mddev, argp);
                  goto done_unlock;

            case GET_DISK_INFO:
                  err = get_disk_info(mddev, argp);
                  goto done_unlock;

            case RESTART_ARRAY_RW:
                  err = restart_array(mddev);
                  goto done_unlock;

            case STOP_ARRAY:
                  err = do_md_stop(mddev, 0, 1);
                  goto done_unlock;

            case STOP_ARRAY_RO:
                  err = do_md_stop(mddev, 1, 1);
                  goto done_unlock;

      }

      /*
       * The remaining ioctls are changing the state of the
       * superblock, so we do not allow them on read-only arrays.
       * However non-MD ioctls (e.g. get-size) will still come through
       * here and hit the 'default' below, so only disallow
       * 'md' ioctls, and switch to rw mode if started auto-readonly.
       */
      if (_IOC_TYPE(cmd) == MD_MAJOR && mddev->ro && mddev->pers) {
            if (mddev->ro == 2) {
                  mddev->ro = 0;
                  sysfs_notify_dirent(mddev->sysfs_state);
                  set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                  md_wakeup_thread(mddev->thread);
            } else {
                  err = -EROFS;
                  goto abort_unlock;
            }
      }

      switch (cmd)
      {
            case ADD_NEW_DISK:
            {
                  mdu_disk_info_t info;
                  if (copy_from_user(&info, argp, sizeof(info)))
                        err = -EFAULT;
                  else
                        err = add_new_disk(mddev, &info);
                  goto done_unlock;
            }

            case HOT_REMOVE_DISK:
                  err = hot_remove_disk(mddev, new_decode_dev(arg));
                  goto done_unlock;

            case HOT_ADD_DISK:
                  err = hot_add_disk(mddev, new_decode_dev(arg));
                  goto done_unlock;

            case SET_DISK_FAULTY:
                  err = set_disk_faulty(mddev, new_decode_dev(arg));
                  goto done_unlock;

            case RUN_ARRAY:
                  err = do_md_run(mddev);
                  goto done_unlock;

            case SET_BITMAP_FILE:
                  err = set_bitmap_file(mddev, (int)arg);
                  goto done_unlock;

            default:
                  err = -EINVAL;
                  goto abort_unlock;
      }

done_unlock:
abort_unlock:
      if (mddev->hold_active == UNTIL_IOCTL &&
          err != -EINVAL)
            mddev->hold_active = 0;
      mddev_unlock(mddev);

      return err;
done:
      if (err)
            MD_BUG();
abort:
      return err;
}

static int md_open(struct block_device *bdev, fmode_t mode)
{
      /*
       * Succeed if we can lock the mddev, which confirms that
       * it isn't being stopped right now.
       */
      mddev_t *mddev = mddev_find(bdev->bd_dev);
      int err;

      if (mddev->gendisk != bdev->bd_disk) {
            /* we are racing with mddev_put which is discarding this
             * bd_disk.
             */
            mddev_put(mddev);
            /* Wait until bdev->bd_disk is definitely gone */
            flush_scheduled_work();
            /* Then retry the open from the top */
            return -ERESTARTSYS;
      }
      BUG_ON(mddev != bdev->bd_disk->private_data);

      if ((err = mutex_lock_interruptible(&mddev->open_mutex)))
            goto out;

      err = 0;
      atomic_inc(&mddev->openers);
      mutex_unlock(&mddev->open_mutex);

      check_disk_change(bdev);
 out:
      return err;
}

static int md_release(struct gendisk *disk, fmode_t mode)
{
      mddev_t *mddev = disk->private_data;

      BUG_ON(!mddev);
      atomic_dec(&mddev->openers);
      mddev_put(mddev);

      return 0;
}

static int md_media_changed(struct gendisk *disk)
{
      mddev_t *mddev = disk->private_data;

      return mddev->changed;
}

static int md_revalidate(struct gendisk *disk)
{
      mddev_t *mddev = disk->private_data;

      mddev->changed = 0;
      return 0;
}
static struct block_device_operations md_fops =
{
      .owner            = THIS_MODULE,
      .open       = md_open,
      .release    = md_release,
      .ioctl            = md_ioctl,
      .getgeo           = md_getgeo,
      .media_changed    = md_media_changed,
      .revalidate_disk= md_revalidate,
};

static int md_thread(void * arg)
{
      mdk_thread_t *thread = arg;

      /*
       * md_thread is a 'system-thread', it's priority should be very
       * high. We avoid resource deadlocks individually in each
       * raid personality. (RAID5 does preallocation) We also use RR and
       * the very same RT priority as kswapd, thus we will never get
       * into a priority inversion deadlock.
       *
       * we definitely have to have equal or higher priority than
       * bdflush, otherwise bdflush will deadlock if there are too
       * many dirty RAID5 blocks.
       */

      allow_signal(SIGKILL);
      while (!kthread_should_stop()) {

            /* We need to wait INTERRUPTIBLE so that
             * we don't add to the load-average.
             * That means we need to be sure no signals are
             * pending
             */
            if (signal_pending(current))
                  flush_signals(current);

            wait_event_interruptible_timeout
                  (thread->wqueue,
                   test_bit(THREAD_WAKEUP, &thread->flags)
                   || kthread_should_stop(),
                   thread->timeout);

            clear_bit(THREAD_WAKEUP, &thread->flags);

            thread->run(thread->mddev);
      }

      return 0;
}

void md_wakeup_thread(mdk_thread_t *thread)
{
      if (thread) {
            dprintk("md: waking up MD thread %s.\n", thread->tsk->comm);
            set_bit(THREAD_WAKEUP, &thread->flags);
            wake_up(&thread->wqueue);
      }
}

mdk_thread_t *md_register_thread(void (*run) (mddev_t *), mddev_t *mddev,
                         const char *name)
{
      mdk_thread_t *thread;

      thread = kzalloc(sizeof(mdk_thread_t), GFP_KERNEL);
      if (!thread)
            return NULL;

      init_waitqueue_head(&thread->wqueue);

      thread->run = run;
      thread->mddev = mddev;
      thread->timeout = MAX_SCHEDULE_TIMEOUT;
      thread->tsk = kthread_run(md_thread, thread, name, mdname(thread->mddev));
      if (IS_ERR(thread->tsk)) {
            kfree(thread);
            return NULL;
      }
      return thread;
}

void md_unregister_thread(mdk_thread_t *thread)
{
      if (!thread)
            return;
      dprintk("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));

      kthread_stop(thread->tsk);
      kfree(thread);
}

void md_error(mddev_t *mddev, mdk_rdev_t *rdev)
{
      if (!mddev) {
            MD_BUG();
            return;
      }

      if (!rdev || test_bit(Faulty, &rdev->flags))
            return;

      if (mddev->external)
            set_bit(Blocked, &rdev->flags);
/*
      dprintk("md_error dev:%s, rdev:(%d:%d), (caller: %p,%p,%p,%p).\n",
            mdname(mddev),
            MAJOR(rdev->bdev->bd_dev), MINOR(rdev->bdev->bd_dev),
            __builtin_return_address(0),__builtin_return_address(1),
            __builtin_return_address(2),__builtin_return_address(3));
*/
      if (!mddev->pers)
            return;
      if (!mddev->pers->error_handler)
            return;
      mddev->pers->error_handler(mddev,rdev);
      if (mddev->degraded)
            set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
      set_bit(StateChanged, &rdev->flags);
      set_bit(MD_RECOVERY_INTR, &mddev->recovery);
      set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
      md_wakeup_thread(mddev->thread);
      md_new_event_inintr(mddev);
}

/* seq_file implementation /proc/mdstat */

static void status_unused(struct seq_file *seq)
{
      int i = 0;
      mdk_rdev_t *rdev;

      seq_printf(seq, "unused devices: ");

      list_for_each_entry(rdev, &pending_raid_disks, same_set) {
            char b[BDEVNAME_SIZE];
            i++;
            seq_printf(seq, "%s ",
                        bdevname(rdev->bdev,b));
      }
      if (!i)
            seq_printf(seq, "<none>");

      seq_printf(seq, "\n");
}


static void status_resync(struct seq_file *seq, mddev_t * mddev)
{
      sector_t max_sectors, resync, res;
      unsigned long dt, db;
      sector_t rt;
      int scale;
      unsigned int per_milli;

      resync = mddev->curr_resync - atomic_read(&mddev->recovery_active);

      if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
            max_sectors = mddev->resync_max_sectors;
      else
            max_sectors = mddev->dev_sectors;

      /*
       * Should not happen.
       */
      if (!max_sectors) {
            MD_BUG();
            return;
      }
      /* Pick 'scale' such that (resync>>scale)*1000 will fit
       * in a sector_t, and (max_sectors>>scale) will fit in a
       * u32, as those are the requirements for sector_div.
       * Thus 'scale' must be at least 10
       */
      scale = 10;
      if (sizeof(sector_t) > sizeof(unsigned long)) {
            while ( max_sectors/2 > (1ULL<<(scale+32)))
                  scale++;
      }
      res = (resync>>scale)*1000;
      sector_div(res, (u32)((max_sectors>>scale)+1));

      per_milli = res;
      {
            int i, x = per_milli/50, y = 20-x;
            seq_printf(seq, "[");
            for (i = 0; i < x; i++)
                  seq_printf(seq, "=");
            seq_printf(seq, ">");
            for (i = 0; i < y; i++)
                  seq_printf(seq, ".");
            seq_printf(seq, "] ");
      }
      seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
               (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
                "reshape" :
                (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)?
                 "check" :
                 (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
                  "resync" : "recovery"))),
               per_milli/10, per_milli % 10,
               (unsigned long long) resync/2,
               (unsigned long long) max_sectors/2);

      /*
       * dt: time from mark until now
       * db: blocks written from mark until now
       * rt: remaining time
       *
       * rt is a sector_t, so could be 32bit or 64bit.
       * So we divide before multiply in case it is 32bit and close
       * to the limit.
       * We scale the divisor (db) by 32 to avoid loosing precision
       * near the end of resync when the number of remaining sectors
       * is close to 'db'.
       * We then divide rt by 32 after multiplying by db to compensate.
       * The '+1' avoids division by zero if db is very small.
       */
      dt = ((jiffies - mddev->resync_mark) / HZ);
      if (!dt) dt++;
      db = (mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active))
            - mddev->resync_mark_cnt;

      rt = max_sectors - resync;    /* number of remaining sectors */
      sector_div(rt, db/32+1);
      rt *= dt;
      rt >>= 5;

      seq_printf(seq, " finish=%lu.%lumin", (unsigned long)rt / 60,
               ((unsigned long)rt % 60)/6);

      seq_printf(seq, " speed=%ldK/sec", db/2/dt);
}

static void *md_seq_start(struct seq_file *seq, loff_t *pos)
{
      struct list_head *tmp;
      loff_t l = *pos;
      mddev_t *mddev;

      if (l >= 0x10000)
            return NULL;
      if (!l--)
            /* header */
            return (void*)1;

      spin_lock(&all_mddevs_lock);
      list_for_each(tmp,&all_mddevs)
            if (!l--) {
                  mddev = list_entry(tmp, mddev_t, all_mddevs);
                  mddev_get(mddev);
                  spin_unlock(&all_mddevs_lock);
                  return mddev;
            }
      spin_unlock(&all_mddevs_lock);
      if (!l--)
            return (void*)2;/* tail */
      return NULL;
}

static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
      struct list_head *tmp;
      mddev_t *next_mddev, *mddev = v;
      
      ++*pos;
      if (v == (void*)2)
            return NULL;

      spin_lock(&all_mddevs_lock);
      if (v == (void*)1)
            tmp = all_mddevs.next;
      else
            tmp = mddev->all_mddevs.next;
      if (tmp != &all_mddevs)
            next_mddev = mddev_get(list_entry(tmp,mddev_t,all_mddevs));
      else {
            next_mddev = (void*)2;
            *pos = 0x10000;
      }           
      spin_unlock(&all_mddevs_lock);

      if (v != (void*)1)
            mddev_put(mddev);
      return next_mddev;

}

static void md_seq_stop(struct seq_file *seq, void *v)
{
      mddev_t *mddev = v;

      if (mddev && v != (void*)1 && v != (void*)2)
            mddev_put(mddev);
}

05856 struct mdstat_info {
      int event;
};

static int md_seq_show(struct seq_file *seq, void *v)
{
      mddev_t *mddev = v;
      sector_t sectors;
      mdk_rdev_t *rdev;
      struct mdstat_info *mi = seq->private;
      struct bitmap *bitmap;

      if (v == (void*)1) {
            struct mdk_personality *pers;
            seq_printf(seq, "Personalities : ");
            spin_lock(&pers_lock);
            list_for_each_entry(pers, &pers_list, list)
                  seq_printf(seq, "[%s] ", pers->name);

            spin_unlock(&pers_lock);
            seq_printf(seq, "\n");
            mi->event = atomic_read(&md_event_count);
            return 0;
      }
      if (v == (void*)2) {
            status_unused(seq);
            return 0;
      }

      if (mddev_lock(mddev) < 0)
            return -EINTR;

      if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
            seq_printf(seq, "%s : %sactive", mdname(mddev),
                                    mddev->pers ? "" : "in");
            if (mddev->pers) {
                  if (mddev->ro==1)
                        seq_printf(seq, " (read-only)");
                  if (mddev->ro==2)
                        seq_printf(seq, " (auto-read-only)");
                  seq_printf(seq, " %s", mddev->pers->name);
            }

            sectors = 0;
            list_for_each_entry(rdev, &mddev->disks, same_set) {
                  char b[BDEVNAME_SIZE];
                  seq_printf(seq, " %s[%d]",
                        bdevname(rdev->bdev,b), rdev->desc_nr);
                  if (test_bit(WriteMostly, &rdev->flags))
                        seq_printf(seq, "(W)");
                  if (test_bit(Faulty, &rdev->flags)) {
                        seq_printf(seq, "(F)");
                        continue;
                  } else if (rdev->raid_disk < 0)
                        seq_printf(seq, "(S)"); /* spare */
                  sectors += rdev->sectors;
            }

            if (!list_empty(&mddev->disks)) {
                  if (mddev->pers)
                        seq_printf(seq, "\n      %llu blocks",
                                 (unsigned long long)
                                 mddev->array_sectors / 2);
                  else
                        seq_printf(seq, "\n      %llu blocks",
                                 (unsigned long long)sectors / 2);
            }
            if (mddev->persistent) {
                  if (mddev->major_version != 0 ||
                      mddev->minor_version != 90) {
                        seq_printf(seq," super %d.%d",
                                 mddev->major_version,
                                 mddev->minor_version);
                  }
            } else if (mddev->external)
                  seq_printf(seq, " super external:%s",
                           mddev->metadata_type);
            else
                  seq_printf(seq, " super non-persistent");

            if (mddev->pers) {
                  mddev->pers->status(seq, mddev);
                  seq_printf(seq, "\n      ");
                  if (mddev->pers->sync_request) {
                        if (mddev->curr_resync > 2) {
                              status_resync(seq, mddev);
                              seq_printf(seq, "\n      ");
                        } else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
                              seq_printf(seq, "\tresync=DELAYED\n      ");
                        else if (mddev->recovery_cp < MaxSector)
                              seq_printf(seq, "\tresync=PENDING\n      ");
                  }
            } else
                  seq_printf(seq, "\n       ");

            if ((bitmap = mddev->bitmap)) {
                  unsigned long chunk_kb;
                  unsigned long flags;
                  spin_lock_irqsave(&bitmap->lock, flags);
                  chunk_kb = bitmap->chunksize >> 10;
                  seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
                        "%lu%s chunk",
                        bitmap->pages - bitmap->missing_pages,
                        bitmap->pages,
                        (bitmap->pages - bitmap->missing_pages)
                              << (PAGE_SHIFT - 10),
                        chunk_kb ? chunk_kb : bitmap->chunksize,
                        chunk_kb ? "KB" : "B");
                  if (bitmap->file) {
                        seq_printf(seq, ", file: ");
                        seq_path(seq, &bitmap->file->f_path, " \t\n");
                  }

                  seq_printf(seq, "\n");
                  spin_unlock_irqrestore(&bitmap->lock, flags);
            }

            seq_printf(seq, "\n");
      }
      mddev_unlock(mddev);
      
      return 0;
}

static const struct seq_operations md_seq_ops = {
      .start  = md_seq_start,
      .next   = md_seq_next,
      .stop   = md_seq_stop,
      .show   = md_seq_show,
};

static int md_seq_open(struct inode *inode, struct file *file)
{
      int error;
      struct mdstat_info *mi = kmalloc(sizeof(*mi), GFP_KERNEL);
      if (mi == NULL)
            return -ENOMEM;

      error = seq_open(file, &md_seq_ops);
      if (error)
            kfree(mi);
      else {
            struct seq_file *p = file->private_data;
            p->private = mi;
            mi->event = atomic_read(&md_event_count);
      }
      return error;
}

static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
{
      struct seq_file *m = filp->private_data;
      struct mdstat_info *mi = m->private;
      int mask;

      poll_wait(filp, &md_event_waiters, wait);

      /* always allow read */
      mask = POLLIN | POLLRDNORM;

      if (mi->event != atomic_read(&md_event_count))
            mask |= POLLERR | POLLPRI;
      return mask;
}

static const struct file_operations md_seq_fops = {
      .owner            = THIS_MODULE,
      .open           = md_seq_open,
      .read           = seq_read,
      .llseek         = seq_lseek,
      .release    = seq_release_private,
      .poll       = mdstat_poll,
};

int register_md_personality(struct mdk_personality *p)
{
      spin_lock(&pers_lock);
      list_add_tail(&p->list, &pers_list);
      printk(KERN_INFO "md: %s personality registered for level %d\n", p->name, p->level);
      spin_unlock(&pers_lock);
      return 0;
}

int unregister_md_personality(struct mdk_personality *p)
{
      printk(KERN_INFO "md: %s personality unregistered\n", p->name);
      spin_lock(&pers_lock);
      list_del_init(&p->list);
      spin_unlock(&pers_lock);
      return 0;
}

static int is_mddev_idle(mddev_t *mddev, int init)
{
      mdk_rdev_t * rdev;
      int idle;
      int curr_events;

      idle = 1;
      rcu_read_lock();
      rdev_for_each_rcu(rdev, mddev) {
            struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
            curr_events = (int)part_stat_read(&disk->part0, sectors[0]) +
                        (int)part_stat_read(&disk->part0, sectors[1]) -
                        atomic_read(&disk->sync_io);
            /* sync IO will cause sync_io to increase before the disk_stats
             * as sync_io is counted when a request starts, and
             * disk_stats is counted when it completes.
             * So resync activity will cause curr_events to be smaller than
             * when there was no such activity.
             * non-sync IO will cause disk_stat to increase without
             * increasing sync_io so curr_events will (eventually)
             * be larger than it was before.  Once it becomes
             * substantially larger, the test below will cause
             * the array to appear non-idle, and resync will slow
             * down.
             * If there is a lot of outstanding resync activity when
             * we set last_event to curr_events, then all that activity
             * completing might cause the array to appear non-idle
             * and resync will be slowed down even though there might
             * not have been non-resync activity.  This will only
             * happen once though.  'last_events' will soon reflect
             * the state where there is little or no outstanding
             * resync requests, and further resync activity will
             * always make curr_events less than last_events.
             *
             */
            if (init || curr_events - rdev->last_events > 64) {
                  rdev->last_events = curr_events;
                  idle = 0;
            }
      }
      rcu_read_unlock();
      return idle;
}

void md_done_sync(mddev_t *mddev, int blocks, int ok)
{
      /* another "blocks" (512byte) blocks have been synced */
      atomic_sub(blocks, &mddev->recovery_active);
      wake_up(&mddev->recovery_wait);
      if (!ok) {
            set_bit(MD_RECOVERY_INTR, &mddev->recovery);
            md_wakeup_thread(mddev->thread);
            // stop recovery, signal do_sync ....
      }
}


/* md_write_start(mddev, bi)
 * If we need to update some array metadata (e.g. 'active' flag
 * in superblock) before writing, schedule a superblock update
 * and wait for it to complete.
 */
void md_write_start(mddev_t *mddev, struct bio *bi)
{
      int did_change = 0;
      if (bio_data_dir(bi) != WRITE)
            return;

      BUG_ON(mddev->ro == 1);
      if (mddev->ro == 2) {
            /* need to switch to read/write */
            mddev->ro = 0;
            set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
            md_wakeup_thread(mddev->thread);
            md_wakeup_thread(mddev->sync_thread);
            did_change = 1;
      }
      atomic_inc(&mddev->writes_pending);
      if (mddev->safemode == 1)
            mddev->safemode = 0;
      if (mddev->in_sync) {
            spin_lock_irq(&mddev->write_lock);
            if (mddev->in_sync) {
                  mddev->in_sync = 0;
                  set_bit(MD_CHANGE_CLEAN, &mddev->flags);
                  md_wakeup_thread(mddev->thread);
                  did_change = 1;
            }
            spin_unlock_irq(&mddev->write_lock);
      }
      if (did_change)
            sysfs_notify_dirent(mddev->sysfs_state);
      wait_event(mddev->sb_wait,
               !test_bit(MD_CHANGE_CLEAN, &mddev->flags) &&
               !test_bit(MD_CHANGE_PENDING, &mddev->flags));
}

void md_write_end(mddev_t *mddev)
{
      if (atomic_dec_and_test(&mddev->writes_pending)) {
            if (mddev->safemode == 2)
                  md_wakeup_thread(mddev->thread);
            else if (mddev->safemode_delay)
                  mod_timer(&mddev->safemode_timer, jiffies + mddev->safemode_delay);
      }
}

/* md_allow_write(mddev)
 * Calling this ensures that the array is marked 'active' so that writes
 * may proceed without blocking.  It is important to call this before
 * attempting a GFP_KERNEL allocation while holding the mddev lock.
 * Must be called with mddev_lock held.
 *
 * In the ->external case MD_CHANGE_CLEAN can not be cleared until mddev->lock
 * is dropped, so return -EAGAIN after notifying userspace.
 */
int md_allow_write(mddev_t *mddev)
{
      if (!mddev->pers)
            return 0;
      if (mddev->ro)
            return 0;
      if (!mddev->pers->sync_request)
            return 0;

      spin_lock_irq(&mddev->write_lock);
      if (mddev->in_sync) {
            mddev->in_sync = 0;
            set_bit(MD_CHANGE_CLEAN, &mddev->flags);
            if (mddev->safemode_delay &&
                mddev->safemode == 0)
                  mddev->safemode = 1;
            spin_unlock_irq(&mddev->write_lock);
            md_update_sb(mddev, 0);
            sysfs_notify_dirent(mddev->sysfs_state);
      } else
            spin_unlock_irq(&mddev->write_lock);

      if (test_bit(MD_CHANGE_CLEAN, &mddev->flags))
            return -EAGAIN;
      else
            return 0;
}
EXPORT_SYMBOL_GPL(md_allow_write);

#define SYNC_MARKS      10
#define     SYNC_MARK_STEP    (3*HZ)
void md_do_sync(mddev_t *mddev)
{
      mddev_t *mddev2;
      unsigned int currspeed = 0,
             window;
      sector_t max_sectors,j, io_sectors;
      unsigned long mark[SYNC_MARKS];
      sector_t mark_cnt[SYNC_MARKS];
      int last_mark,m;
      struct list_head *tmp;
      sector_t last_check;
      int skipped = 0;
      mdk_rdev_t *rdev;
      char *desc;

      /* just incase thread restarts... */
      if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
            return;
      if (mddev->ro) /* never try to sync a read-only array */
            return;

      if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
            if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
                  desc = "data-check";
            else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
                  desc = "requested-resync";
            else
                  desc = "resync";
      } else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
            desc = "reshape";
      else
            desc = "recovery";

      /* we overload curr_resync somewhat here.
       * 0 == not engaged in resync at all
       * 2 == checking that there is no conflict with another sync
       * 1 == like 2, but have yielded to allow conflicting resync to
       *          commense
       * other == active in resync - this many blocks
       *
       * Before starting a resync we must have set curr_resync to
       * 2, and then checked that every "conflicting" array has curr_resync
       * less than ours.  When we find one that is the same or higher
       * we wait on resync_wait.  To avoid deadlock, we reduce curr_resync
       * to 1 if we choose to yield (based arbitrarily on address of mddev structure).
       * This will mean we have to start checking from the beginning again.
       *
       */

      do {
            mddev->curr_resync = 2;

      try_again:
            if (kthread_should_stop()) {
                  set_bit(MD_RECOVERY_INTR, &mddev->recovery);
                  goto skip;
            }
            for_each_mddev(mddev2, tmp) {
                  if (mddev2 == mddev)
                        continue;
                  if (!mddev->parallel_resync
                  &&  mddev2->curr_resync
                  &&  match_mddev_units(mddev, mddev2)) {
                        DEFINE_WAIT(wq);
                        if (mddev < mddev2 && mddev->curr_resync == 2) {
                              /* arbitrarily yield */
                              mddev->curr_resync = 1;
                              wake_up(&resync_wait);
                        }
                        if (mddev > mddev2 && mddev->curr_resync == 1)
                              /* no need to wait here, we can wait the next
                               * time 'round when curr_resync == 2
                               */
                              continue;
                        /* We need to wait 'interruptible' so as not to
                         * contribute to the load average, and not to
                         * be caught by 'softlockup'
                         */
                        prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE);
                        if (!kthread_should_stop() &&
                            mddev2->curr_resync >= mddev->curr_resync) {
                              printk(KERN_INFO "md: delaying %s of %s"
                                     " until %s has finished (they"
                                     " share one or more physical units)\n",
                                     desc, mdname(mddev), mdname(mddev2));
                              mddev_put(mddev2);
                              if (signal_pending(current))
                                    flush_signals(current);
                              schedule();
                              finish_wait(&resync_wait, &wq);
                              goto try_again;
                        }
                        finish_wait(&resync_wait, &wq);
                  }
            }
      } while (mddev->curr_resync < 2);

      j = 0;
      if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
            /* resync follows the size requested by the personality,
             * which defaults to physical size, but can be virtual size
             */
            max_sectors = mddev->resync_max_sectors;
            mddev->resync_mismatches = 0;
            /* we don't use the checkpoint if there's a bitmap */
            if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
                  j = mddev->resync_min;
            else if (!mddev->bitmap)
                  j = mddev->recovery_cp;

      } else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
            max_sectors = mddev->dev_sectors;
      else {
            /* recovery follows the physical size of devices */
            max_sectors = mddev->dev_sectors;
            j = MaxSector;
            list_for_each_entry(rdev, &mddev->disks, same_set)
                  if (rdev->raid_disk >= 0 &&
                      !test_bit(Faulty, &rdev->flags) &&
                      !test_bit(In_sync, &rdev->flags) &&
                      rdev->recovery_offset < j)
                        j = rdev->recovery_offset;
      }

      printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
      printk(KERN_INFO "md: minimum _guaranteed_  speed:"
            " %d KB/sec/disk.\n", speed_min(mddev));
      printk(KERN_INFO "md: using maximum available idle IO bandwidth "
             "(but not more than %d KB/sec) for %s.\n",
             speed_max(mddev), desc);

      is_mddev_idle(mddev, 1); /* this initializes IO event counters */

      io_sectors = 0;
      for (m = 0; m < SYNC_MARKS; m++) {
            mark[m] = jiffies;
            mark_cnt[m] = io_sectors;
      }
      last_mark = 0;
      mddev->resync_mark = mark[last_mark];
      mddev->resync_mark_cnt = mark_cnt[last_mark];

      /*
       * Tune reconstruction:
       */
      window = 32*(PAGE_SIZE/512);
      printk(KERN_INFO "md: using %dk window, over a total of %llu blocks.\n",
            window/2,(unsigned long long) max_sectors/2);

      atomic_set(&mddev->recovery_active, 0);
      last_check = 0;

      if (j>2) {
            printk(KERN_INFO 
                   "md: resuming %s of %s from checkpoint.\n",
                   desc, mdname(mddev));
            mddev->curr_resync = j;
      }

      while (j < max_sectors) {
            sector_t sectors;

            skipped = 0;

            if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
                ((mddev->curr_resync > mddev->curr_resync_completed &&
                  (mddev->curr_resync - mddev->curr_resync_completed)
                  > (max_sectors >> 4)) ||
                 (j - mddev->curr_resync_completed)*2
                 >= mddev->resync_max - mddev->curr_resync_completed
                      )) {
                  /* time to update curr_resync_completed */
                  blk_unplug(mddev->queue);
                  wait_event(mddev->recovery_wait,
                           atomic_read(&mddev->recovery_active) == 0);
                  mddev->curr_resync_completed =
                        mddev->curr_resync;
                  set_bit(MD_CHANGE_CLEAN, &mddev->flags);
                  sysfs_notify(&mddev->kobj, NULL, "sync_completed");
            }

            while (j >= mddev->resync_max && !kthread_should_stop()) {
                  /* As this condition is controlled by user-space,
                   * we can block indefinitely, so use '_interruptible'
                   * to avoid triggering warnings.
                   */
                  flush_signals(current); /* just in case */
                  wait_event_interruptible(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));
            if (sectors == 0) {
                  set_bit(MD_RECOVERY_INTR, &mddev->recovery);
                  goto out;
            }

            if (!skipped) { /* actual IO requested */
                  io_sectors += sectors;
                  atomic_add(sectors, &mddev->recovery_active);
            }

            j += sectors;
            if (j>1) mddev->curr_resync = j;
            mddev->curr_mark_cnt = io_sectors;
            if (last_check == 0)
                  /* this is the earliers that rebuilt will be
                   * visible in /proc/mdstat
                   */
                  md_new_event(mddev);

            if (last_check + window > io_sectors || j == max_sectors)
                  continue;

            last_check = io_sectors;

            if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
                  break;

      repeat:
            if (time_after_eq(jiffies, mark[last_mark] + SYNC_MARK_STEP )) {
                  /* step marks */
                  int next = (last_mark+1) % SYNC_MARKS;

                  mddev->resync_mark = mark[next];
                  mddev->resync_mark_cnt = mark_cnt[next];
                  mark[next] = jiffies;
                  mark_cnt[next] = io_sectors - atomic_read(&mddev->recovery_active);
                  last_mark = next;
            }


            if (kthread_should_stop())
                  goto interrupted;


            /*
             * this loop exits only if either when we are slower than
             * the 'hard' speed limit, or the system was IO-idle for
             * a jiffy.
             * the system might be non-idle CPU-wise, but we only care
             * about not overloading the IO subsystem. (things like an
             * e2fsck being done on the RAID array should execute fast)
             */
            blk_unplug(mddev->queue);
            cond_resched();

            currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
                  /((jiffies-mddev->resync_mark)/HZ +1) +1;

            if (currspeed > speed_min(mddev)) {
                  if ((currspeed > speed_max(mddev)) ||
                              !is_mddev_idle(mddev, 0)) {
                        msleep(500);
                        goto repeat;
                  }
            }
      }
      printk(KERN_INFO "md: %s: %s done.\n",mdname(mddev), desc);
      /*
       * this also signals 'finished resyncing' to md_stop
       */
 out:
      blk_unplug(mddev->queue);

      wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));

      /* tell personality that we are finished */
      mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);

      if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
          mddev->curr_resync > 2) {
            if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
                  if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
                        if (mddev->curr_resync >= mddev->recovery_cp) {
                              printk(KERN_INFO
                                     "md: checkpointing %s of %s.\n",
                                     desc, mdname(mddev));
                              mddev->recovery_cp = mddev->curr_resync;
                        }
                  } else
                        mddev->recovery_cp = MaxSector;
            } else {
                  if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
                        mddev->curr_resync = MaxSector;
                  list_for_each_entry(rdev, &mddev->disks, same_set)
                        if (rdev->raid_disk >= 0 &&
                            !test_bit(Faulty, &rdev->flags) &&
                            !test_bit(In_sync, &rdev->flags) &&
                            rdev->recovery_offset < mddev->curr_resync)
                              rdev->recovery_offset = mddev->curr_resync;
            }
      }
      set_bit(MD_CHANGE_DEVS, &mddev->flags);

 skip:
      mddev->curr_resync = 0;
      mddev->curr_resync_completed = 0;
      mddev->resync_min = 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);


static int remove_and_add_spares(mddev_t *mddev)
{
      mdk_rdev_t *rdev;
      int spares = 0;

      mddev->curr_resync_completed = 0;

      list_for_each_entry(rdev, &mddev->disks, same_set)
            if (rdev->raid_disk >= 0 &&
                !test_bit(Blocked, &rdev->flags) &&
                (test_bit(Faulty, &rdev->flags) ||
                 ! test_bit(In_sync, &rdev->flags)) &&
                atomic_read(&rdev->nr_pending)==0) {
                  if (mddev->pers->hot_remove_disk(
                            mddev, rdev->raid_disk)==0) {
                        char nm[20];
                        sprintf(nm,"rd%d", rdev->raid_disk);
                        sysfs_remove_link(&mddev->kobj, nm);
                        rdev->raid_disk = -1;
                  }
            }

      if (mddev->degraded && ! mddev->ro && !mddev->recovery_disabled) {
            list_for_each_entry(rdev, &mddev->disks, same_set) {
                  if (rdev->raid_disk >= 0 &&
                      !test_bit(In_sync, &rdev->flags) &&
                      !test_bit(Blocked, &rdev->flags))
                        spares++;
                  if (rdev->raid_disk < 0
                      && !test_bit(Faulty, &rdev->flags)) {
                        rdev->recovery_offset = 0;
                        if (mddev->pers->
                            hot_add_disk(mddev, rdev) == 0) {
                              char nm[20];
                              sprintf(nm, "rd%d", rdev->raid_disk);
                              if (sysfs_create_link(&mddev->kobj,
                                                &rdev->kobj, nm))
                                    printk(KERN_WARNING
                                           "md: cannot register "
                                           "%s for %s\n",
                                           nm, mdname(mddev));
                              spares++;
                              md_new_event(mddev);
                        } else
                              break;
                  }
            }
      }
      return spares;
}
/*
 * This routine is regularly called by all per-raid-array threads to
 * deal with generic issues like resync and super-block update.
 * Raid personalities that don't have a thread (linear/raid0) do not
 * need this as they never do any recovery or update the superblock.
 *
 * It does not do any resync itself, but rather "forks" off other threads
 * to do that as needed.
 * When it is determined that resync is needed, we set MD_RECOVERY_RUNNING in
 * "->recovery" and create a thread at ->sync_thread.
 * When the thread finishes it sets MD_RECOVERY_DONE
 * and wakeups up this thread which will reap the thread and finish up.
 * This thread also removes any faulty devices (with nr_pending == 0).
 *
 * The overall approach is:
 *  1/ if the superblock needs updating, update it.
 *  2/ If a recovery thread is running, don't do anything else.
 *  3/ If recovery has finished, clean up, possibly marking spares active.
 *  4/ If there are any faulty devices, remove them.
 *  5/ If array is degraded, try to add spares devices
 *  6/ If array has spares or is not in-sync, start a resync thread.
 */
void md_check_recovery(mddev_t *mddev)
{
      mdk_rdev_t *rdev;


      if (mddev->bitmap)
            bitmap_daemon_work(mddev->bitmap);

      if (mddev->ro)
            return;

      if (signal_pending(current)) {
            if (mddev->pers->sync_request && !mddev->external) {
                  printk(KERN_INFO "md: %s in immediate safe mode\n",
                         mdname(mddev));
                  mddev->safemode = 2;
            }
            flush_signals(current);
      }

      if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
            return;
      if ( ! (
            (mddev->flags && !mddev->external) ||
            test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
            test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
            (mddev->external == 0 && mddev->safemode == 1) ||
            (mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending)
             && !mddev->in_sync && mddev->recovery_cp == MaxSector)
            ))
            return;

      if (mddev_trylock(mddev)) {
            int spares = 0;

            if (mddev->ro) {
                  /* Only thing we do on a ro array is remove
                   * failed devices.
                   */
                  remove_and_add_spares(mddev);
                  clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                  goto unlock;
            }

            if (!mddev->external) {
                  int did_change = 0;
                  spin_lock_irq(&mddev->write_lock);
                  if (mddev->safemode &&
                      !atomic_read(&mddev->writes_pending) &&
                      !mddev->in_sync &&
                      mddev->recovery_cp == MaxSector) {
                        mddev->in_sync = 1;
                        did_change = 1;
                        if (mddev->persistent)
                              set_bit(MD_CHANGE_CLEAN, &mddev->flags);
                  }
                  if (mddev->safemode == 1)
                        mddev->safemode = 0;
                  spin_unlock_irq(&mddev->write_lock);
                  if (did_change)
                        sysfs_notify_dirent(mddev->sysfs_state);
            }

            if (mddev->flags)
                  md_update_sb(mddev, 0);

            list_for_each_entry(rdev, &mddev->disks, same_set)
                  if (test_and_clear_bit(StateChanged, &rdev->flags))
                        sysfs_notify_dirent(rdev->sysfs_state);


            if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
                !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
                  /* resync/recovery still happening */
                  clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                  goto unlock;
            }
            if (mddev->sync_thread) {
                  /* resync has finished, collect result */
                  md_unregister_thread(mddev->sync_thread);
                  mddev->sync_thread = NULL;
                  if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
                      !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
                        /* success...*/
                        /* activate any spares */
                        if (mddev->pers->spare_active(mddev))
                              sysfs_notify(&mddev->kobj, NULL,
                                         "degraded");
                  }
                  if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
                      mddev->pers->finish_reshape)
                        mddev->pers->finish_reshape(mddev);
                  md_update_sb(mddev, 1);

                  /* if array is no-longer degraded, then any saved_raid_disk
                   * information must be scrapped
                   */
                  if (!mddev->degraded)
                        list_for_each_entry(rdev, &mddev->disks, same_set)
                              rdev->saved_raid_disk = -1;

                  mddev->recovery = 0;
                  /* flag recovery needed just to double check */
                  set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                  sysfs_notify_dirent(mddev->sysfs_action);
                  md_new_event(mddev);
                  goto unlock;
            }
            /* Set RUNNING before clearing NEEDED to avoid
             * any transients in the value of "sync_action".
             */
            set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
            clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
            /* Clear some bits that don't mean anything, but
             * might be left set
             */
            clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
            clear_bit(MD_RECOVERY_DONE, &mddev->recovery);

            if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
                  goto unlock;
            /* no recovery is running.
             * remove any failed drives, then
             * add spares if possible.
             * Spare are also removed and re-added, to allow
             * the personality to fail the re-add.
             */

            if (mddev->reshape_position != MaxSector) {
                  if (mddev->pers->check_reshape == NULL ||
                      mddev->pers->check_reshape(mddev) != 0)
                        /* Cannot proceed */
                        goto unlock;
                  set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
                  clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
            } else if ((spares = remove_and_add_spares(mddev))) {
                  clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
                  clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
                  clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
                  set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
            } else if (mddev->recovery_cp < MaxSector) {
                  set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
                  clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
            } else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
                  /* nothing to be done ... */
                  goto unlock;

            if (mddev->pers->sync_request) {
                  if (spares && mddev->bitmap && ! mddev->bitmap->file) {
                        /* We are adding a device or devices to an array
                         * which has the bitmap stored on all devices.
                         * So make sure all bitmap pages get written
                         */
                        bitmap_write_all(mddev->bitmap);
                  }
                  mddev->sync_thread = md_register_thread(md_do_sync,
                                                mddev,
                                                "%s_resync");
                  if (!mddev->sync_thread) {
                        printk(KERN_ERR "%s: could not start resync"
                              " thread...\n", 
                              mdname(mddev));
                        /* leave the spares where they are, it shouldn't hurt */
                        mddev->recovery = 0;
                  } else
                        md_wakeup_thread(mddev->sync_thread);
                  sysfs_notify_dirent(mddev->sysfs_action);
                  md_new_event(mddev);
            }
      unlock:
            if (!mddev->sync_thread) {
                  clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
                  if (test_and_clear_bit(MD_RECOVERY_RECOVER,
                                     &mddev->recovery))
                        if (mddev->sysfs_action)
                              sysfs_notify_dirent(mddev->sysfs_action);
            }
            mddev_unlock(mddev);
      }
}

void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
{
      sysfs_notify_dirent(rdev->sysfs_state);
      wait_event_timeout(rdev->blocked_wait,
                     !test_bit(Blocked, &rdev->flags),
                     msecs_to_jiffies(5000));
      rdev_dec_pending(rdev, mddev);
}
EXPORT_SYMBOL(md_wait_for_blocked_rdev);

static int md_notify_reboot(struct notifier_block *this,
                      unsigned long code, void *x)
{
      struct list_head *tmp;
      mddev_t *mddev;

      if ((code == SYS_DOWN) || (code == SYS_HALT) || (code == SYS_POWER_OFF)) {

            printk(KERN_INFO "md: stopping all md devices.\n");

            for_each_mddev(mddev, tmp)
                  if (mddev_trylock(mddev)) {
                        /* Force a switch to readonly even array
                         * appears to still be in use.  Hence
                         * the '100'.
                         */
                        do_md_stop(mddev, 1, 100);
                        mddev_unlock(mddev);
                  }
            /*
             * certain more exotic SCSI devices are known to be
             * volatile wrt too early system reboots. While the
             * right place to handle this issue is the given
             * driver, we do want to have a safe RAID driver ...
             */
            mdelay(1000*1);
      }
      return NOTIFY_DONE;
}

static struct notifier_block md_notifier = {
      .notifier_call    = md_notify_reboot,
      .next       = NULL,
      .priority   = INT_MAX, /* before any real devices */
};

static void md_geninit(void)
{
      dprintk("md: sizeof(mdp_super_t) = %d\n", (int)sizeof(mdp_super_t));

      proc_create("mdstat", S_IRUGO, NULL, &md_seq_fops);
}

static int __init md_init(void)
{
      if (register_blkdev(MD_MAJOR, "md"))
            return -1;
      if ((mdp_major=register_blkdev(0, "mdp"))<=0) {
            unregister_blkdev(MD_MAJOR, "md");
            return -1;
      }
      blk_register_region(MKDEV(MD_MAJOR, 0), 1UL<<MINORBITS, THIS_MODULE,
                      md_probe, NULL, NULL);
      blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
                      md_probe, NULL, NULL);

      register_reboot_notifier(&md_notifier);
      raid_table_header = register_sysctl_table(raid_root_table);

      md_geninit();
      return 0;
}


#ifndef MODULE

/*
 * Searches all registered partitions for autorun RAID arrays
 * at boot time.
 */

static LIST_HEAD(all_detected_devices);
06854 struct detected_devices_node {
      struct list_head list;
      dev_t dev;
};

void md_autodetect_dev(dev_t dev)
{
      struct detected_devices_node *node_detected_dev;

      node_detected_dev = kzalloc(sizeof(*node_detected_dev), GFP_KERNEL);
      if (node_detected_dev) {
            node_detected_dev->dev = dev;
            list_add_tail(&node_detected_dev->list, &all_detected_devices);
      } else {
            printk(KERN_CRIT "md: md_autodetect_dev: kzalloc failed"
                  ", skipping dev(%d,%d)\n", MAJOR(dev), MINOR(dev));
      }
}


static void autostart_arrays(int part)
{
      mdk_rdev_t *rdev;
      struct detected_devices_node *node_detected_dev;
      dev_t dev;
      int i_scanned, i_passed;

      i_scanned = 0;
      i_passed = 0;

      printk(KERN_INFO "md: Autodetecting RAID arrays.\n");

      while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) {
            i_scanned++;
            node_detected_dev = list_entry(all_detected_devices.next,
                              struct detected_devices_node, list);
            list_del(&node_detected_dev->list);
            dev = node_detected_dev->dev;
            kfree(node_detected_dev);
            rdev = md_import_device(dev,0, 90);
            if (IS_ERR(rdev))
                  continue;

            if (test_bit(Faulty, &rdev->flags)) {
                  MD_BUG();
                  continue;
            }
            set_bit(AutoDetected, &rdev->flags);
            list_add(&rdev->same_set, &pending_raid_disks);
            i_passed++;
      }

      printk(KERN_INFO "md: Scanned %d and added %d devices.\n",
                                    i_scanned, i_passed);

      autorun_devices(part);
}

#endif /* !MODULE */

static __exit void md_exit(void)
{
      mddev_t *mddev;
      struct list_head *tmp;

      blk_unregister_region(MKDEV(MD_MAJOR,0), 1U << MINORBITS);
      blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);

      unregister_blkdev(MD_MAJOR,"md");
      unregister_blkdev(mdp_major, "mdp");
      unregister_reboot_notifier(&md_notifier);
      unregister_sysctl_table(raid_table_header);
      remove_proc_entry("mdstat", NULL);
      for_each_mddev(mddev, tmp) {
            export_array(mddev);
            mddev->hold_active = 0;
      }
}

subsys_initcall(md_init);
module_exit(md_exit)

static int get_ro(char *buffer, struct kernel_param *kp)
{
      return sprintf(buffer, "%d", start_readonly);
}
static int set_ro(const char *val, struct kernel_param *kp)
{
      char *e;
      int num = simple_strtoul(val, &e, 10);
      if (*val && (*e == '\0' || *e == '\n')) {
            start_readonly = num;
            return 0;
      }
      return -EINVAL;
}

module_param_call(start_ro, set_ro, get_ro, NULL, S_IRUSR|S_IWUSR);
module_param(start_dirty_degraded, int, S_IRUGO|S_IWUSR);

module_param_call(new_array, add_named_array, NULL, NULL, S_IWUSR);

EXPORT_SYMBOL(register_md_personality);
EXPORT_SYMBOL(unregister_md_personality);
EXPORT_SYMBOL(md_error);
EXPORT_SYMBOL(md_done_sync);
EXPORT_SYMBOL(md_write_start);
EXPORT_SYMBOL(md_write_end);
EXPORT_SYMBOL(md_register_thread);
EXPORT_SYMBOL(md_unregister_thread);
EXPORT_SYMBOL(md_wakeup_thread);
EXPORT_SYMBOL(md_check_recovery);
MODULE_LICENSE("GPL");
MODULE_ALIAS("md");
MODULE_ALIAS_BLOCKDEV_MAJOR(MD_MAJOR);

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