md: move md_k.h from include/linux/raid/ to drivers/md/
[safe/jmp/linux-2.6] / drivers / md / raid1.c
index a8bc93d..051ecfa 100644 (file)
@@ -9,7 +9,7 @@
  *
  * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
  *
- * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
+ * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
  * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
  *
  * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include <linux/delay.h>
+#include <linux/blkdev.h>
+#include <linux/seq_file.h>
+#include "md.h"
 #include "dm-bio-list.h"
-#include <linux/raid/raid1.h>
-#include <linux/raid/bitmap.h>
+#include "raid1.h"
+#include "bitmap.h"
 
 #define DEBUG 0
 #if DEBUG
@@ -47,7 +51,6 @@
  */
 #define        NR_RAID1_BIOS 256
 
-static mdk_personality_t raid1_personality;
 
 static void unplug_slaves(mddev_t *mddev);
 
@@ -61,10 +64,8 @@ static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
        int size = offsetof(r1bio_t, bios[pi->raid_disks]);
 
        /* allocate a r1bio with room for raid_disks entries in the bios array */
-       r1_bio = kmalloc(size, gfp_flags);
-       if (r1_bio)
-               memset(r1_bio, 0, size);
-       else
+       r1_bio = kzalloc(size, gfp_flags);
+       if (!r1_bio)
                unplug_slaves(pi->mddev);
 
        return r1_bio;
@@ -106,15 +107,30 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
        }
        /*
         * Allocate RESYNC_PAGES data pages and attach them to
-        * the first bio;
+        * the first bio.
+        * If this is a user-requested check/repair, allocate
+        * RESYNC_PAGES for each bio.
         */
-       bio = r1_bio->bios[0];
-       for (i = 0; i < RESYNC_PAGES; i++) {
-               page = alloc_page(gfp_flags);
-               if (unlikely(!page))
-                       goto out_free_pages;
-
-               bio->bi_io_vec[i].bv_page = page;
+       if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
+               j = pi->raid_disks;
+       else
+               j = 1;
+       while(j--) {
+               bio = r1_bio->bios[j];
+               for (i = 0; i < RESYNC_PAGES; i++) {
+                       page = alloc_page(gfp_flags);
+                       if (unlikely(!page))
+                               goto out_free_pages;
+
+                       bio->bi_io_vec[i].bv_page = page;
+               }
+       }
+       /* If not user-requests, copy the page pointers to all bios */
+       if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
+               for (i=0; i<RESYNC_PAGES ; i++)
+                       for (j=1; j<pi->raid_disks; j++)
+                               r1_bio->bios[j]->bi_io_vec[i].bv_page =
+                                       r1_bio->bios[0]->bi_io_vec[i].bv_page;
        }
 
        r1_bio->master_bio = NULL;
@@ -122,8 +138,10 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
        return r1_bio;
 
 out_free_pages:
-       for ( ; i > 0 ; i--)
-               __free_page(bio->bi_io_vec[i-1].bv_page);
+       for (i=0; i < RESYNC_PAGES ; i++)
+               for (j=0 ; j < pi->raid_disks; j++)
+                       safe_put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
+       j = -1;
 out_free_bio:
        while ( ++j < pi->raid_disks )
                bio_put(r1_bio->bios[j]);
@@ -134,14 +152,16 @@ out_free_bio:
 static void r1buf_pool_free(void *__r1_bio, void *data)
 {
        struct pool_info *pi = data;
-       int i;
+       int i,j;
        r1bio_t *r1bio = __r1_bio;
-       struct bio *bio = r1bio->bios[0];
 
-       for (i = 0; i < RESYNC_PAGES; i++) {
-               __free_page(bio->bi_io_vec[i].bv_page);
-               bio->bi_io_vec[i].bv_page = NULL;
-       }
+       for (i = 0; i < RESYNC_PAGES; i++)
+               for (j = pi->raid_disks; j-- ;) {
+                       if (j == 0 ||
+                           r1bio->bios[j]->bi_io_vec[i].bv_page !=
+                           r1bio->bios[0]->bi_io_vec[i].bv_page)
+                               safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
+               }
        for (i=0 ; i < pi->raid_disks; i++)
                bio_put(r1bio->bios[i]);
 
@@ -160,7 +180,7 @@ static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
        }
 }
 
-static inline void free_r1bio(r1bio_t *r1_bio)
+static void free_r1bio(r1bio_t *r1_bio)
 {
        conf_t *conf = mddev_to_conf(r1_bio->mddev);
 
@@ -174,7 +194,7 @@ static inline void free_r1bio(r1bio_t *r1_bio)
        mempool_free(r1_bio, conf->r1bio_pool);
 }
 
-static inline void put_buf(r1bio_t *r1_bio)
+static void put_buf(r1bio_t *r1_bio)
 {
        conf_t *conf = mddev_to_conf(r1_bio->mddev);
        int i;
@@ -222,7 +242,7 @@ static void raid_end_bio_io(r1bio_t *r1_bio)
                        (unsigned long long) bio->bi_sector +
                                (bio->bi_size >> 9) - 1);
 
-               bio_endio(bio, bio->bi_size,
+               bio_endio(bio,
                        test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
        }
        free_r1bio(r1_bio);
@@ -239,36 +259,38 @@ static inline void update_head_pos(int disk, r1bio_t *r1_bio)
                r1_bio->sector + (r1_bio->sectors);
 }
 
-static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
+static void raid1_end_read_request(struct bio *bio, int error)
 {
        int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
        r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
        int mirror;
        conf_t *conf = mddev_to_conf(r1_bio->mddev);
 
-       if (bio->bi_size)
-               return 1;
-       
        mirror = r1_bio->read_disk;
        /*
         * this branch is our 'one mirror IO has finished' event handler:
         */
        update_head_pos(mirror, r1_bio);
 
-       if (uptodate || conf->working_disks <= 1) {
-               /*
-                * Set R1BIO_Uptodate in our master bio, so that
-                * we will return a good error code for to the higher
-                * levels even if IO on some other mirrored buffer fails.
-                *
-                * The 'master' represents the composite IO operation to
-                * user-side. So if something waits for IO, then it will
-                * wait for the 'master' bio.
-                */
+       if (uptodate)
                set_bit(R1BIO_Uptodate, &r1_bio->state);
+       else {
+               /* If all other devices have failed, we want to return
+                * the error upwards rather than fail the last device.
+                * Here we redefine "uptodate" to mean "Don't want to retry"
+                */
+               unsigned long flags;
+               spin_lock_irqsave(&conf->device_lock, flags);
+               if (r1_bio->mddev->degraded == conf->raid_disks ||
+                   (r1_bio->mddev->degraded == conf->raid_disks-1 &&
+                    !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
+                       uptodate = 1;
+               spin_unlock_irqrestore(&conf->device_lock, flags);
+       }
 
+       if (uptodate)
                raid_end_bio_io(r1_bio);
-       else {
+       else {
                /*
                 * oops, read error:
                 */
@@ -280,32 +302,32 @@ static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int
        }
 
        rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
-       return 0;
 }
 
-static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
+static void raid1_end_write_request(struct bio *bio, int error)
 {
        int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
        r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
        int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
        conf_t *conf = mddev_to_conf(r1_bio->mddev);
+       struct bio *to_put = NULL;
 
-       if (bio->bi_size)
-               return 1;
 
        for (mirror = 0; mirror < conf->raid_disks; mirror++)
                if (r1_bio->bios[mirror] == bio)
                        break;
 
-       if (error == -ENOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
+       if (error == -EOPNOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
                set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
                set_bit(R1BIO_BarrierRetry, &r1_bio->state);
                r1_bio->mddev->barriers_work = 0;
+               /* Don't rdev_dec_pending in this branch - keep it for the retry */
        } else {
                /*
                 * this branch is our 'one mirror IO has finished' event handler:
                 */
                r1_bio->bios[mirror] = NULL;
+               to_put = bio;
                if (!uptodate) {
                        md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
                        /* an I/O failed, we can't clear the bitmap */
@@ -342,10 +364,11 @@ static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int
                                               (unsigned long long) mbio->bi_sector,
                                               (unsigned long long) mbio->bi_sector +
                                               (mbio->bi_size >> 9) - 1);
-                                       bio_endio(mbio, mbio->bi_size, 0);
+                                       bio_endio(mbio, 0);
                                }
                        }
                }
+               rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
        }
        /*
         *
@@ -353,33 +376,28 @@ static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int
         * already.
         */
        if (atomic_dec_and_test(&r1_bio->remaining)) {
-               if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
+               if (test_bit(R1BIO_BarrierRetry, &r1_bio->state))
                        reschedule_retry(r1_bio);
-                       /* Don't dec_pending yet, we want to hold
-                        * the reference over the retry
-                        */
-                       return 0;
-               }
-               if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
-                       /* free extra copy of the data pages */
-                       int i = bio->bi_vcnt;
-                       while (i--)
-                               __free_page(bio->bi_io_vec[i].bv_page);
+               else {
+                       /* it really is the end of this request */
+                       if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
+                               /* free extra copy of the data pages */
+                               int i = bio->bi_vcnt;
+                               while (i--)
+                                       safe_put_page(bio->bi_io_vec[i].bv_page);
+                       }
+                       /* clear the bitmap if all writes complete successfully */
+                       bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
+                                       r1_bio->sectors,
+                                       !test_bit(R1BIO_Degraded, &r1_bio->state),
+                                       behind);
+                       md_write_end(r1_bio->mddev);
+                       raid_end_bio_io(r1_bio);
                }
-               /* clear the bitmap if all writes complete successfully */
-               bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
-                               r1_bio->sectors,
-                               !test_bit(R1BIO_Degraded, &r1_bio->state),
-                               behind);
-               md_write_end(r1_bio->mddev);
-               raid_end_bio_io(r1_bio);
        }
 
-       if (r1_bio->bios[mirror]==NULL)
-               bio_put(bio);
-
-       rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
-       return 0;
+       if (to_put)
+               bio_put(to_put);
 }
 
 
@@ -510,7 +528,7 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio)
                        /* cannot risk returning a device that failed
                         * before we inc'ed nr_pending
                         */
-                       atomic_dec(&rdev->nr_pending);
+                       rdev_dec_pending(rdev, conf->mddev);
                        goto retry;
                }
                conf->next_seq_sect = this_sector + sectors;
@@ -530,13 +548,12 @@ static void unplug_slaves(mddev_t *mddev)
        for (i=0; i<mddev->raid_disks; i++) {
                mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
                if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
-                       request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
+                       struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
 
                        atomic_inc(&rdev->nr_pending);
                        rcu_read_unlock();
 
-                       if (r_queue->unplug_fn)
-                               r_queue->unplug_fn(r_queue);
+                       blk_unplug(r_queue);
 
                        rdev_dec_pending(rdev, mddev);
                        rcu_read_lock();
@@ -545,7 +562,7 @@ static void unplug_slaves(mddev_t *mddev)
        rcu_read_unlock();
 }
 
-static void raid1_unplug(request_queue_t *q)
+static void raid1_unplug(struct request_queue *q)
 {
        mddev_t *mddev = q->queuedata;
 
@@ -553,36 +570,63 @@ static void raid1_unplug(request_queue_t *q)
        md_wakeup_thread(mddev->thread);
 }
 
-static int raid1_issue_flush(request_queue_t *q, struct gendisk *disk,
-                            sector_t *error_sector)
+static int raid1_congested(void *data, int bits)
 {
-       mddev_t *mddev = q->queuedata;
+       mddev_t *mddev = data;
        conf_t *conf = mddev_to_conf(mddev);
        int i, ret = 0;
 
        rcu_read_lock();
-       for (i=0; i<mddev->raid_disks && ret == 0; i++) {
+       for (i = 0; i < mddev->raid_disks; i++) {
                mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
                if (rdev && !test_bit(Faulty, &rdev->flags)) {
-                       struct block_device *bdev = rdev->bdev;
-                       request_queue_t *r_queue = bdev_get_queue(bdev);
+                       struct request_queue *q = bdev_get_queue(rdev->bdev);
 
-                       if (!r_queue->issue_flush_fn)
-                               ret = -EOPNOTSUPP;
-                       else {
-                               atomic_inc(&rdev->nr_pending);
-                               rcu_read_unlock();
-                               ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
-                                                             error_sector);
-                               rdev_dec_pending(rdev, mddev);
-                               rcu_read_lock();
-                       }
+                       /* Note the '|| 1' - when read_balance prefers
+                        * non-congested targets, it can be removed
+                        */
+                       if ((bits & (1<<BDI_write_congested)) || 1)
+                               ret |= bdi_congested(&q->backing_dev_info, bits);
+                       else
+                               ret &= bdi_congested(&q->backing_dev_info, bits);
                }
        }
        rcu_read_unlock();
        return ret;
 }
 
+
+static int flush_pending_writes(conf_t *conf)
+{
+       /* Any writes that have been queued but are awaiting
+        * bitmap updates get flushed here.
+        * We return 1 if any requests were actually submitted.
+        */
+       int rv = 0;
+
+       spin_lock_irq(&conf->device_lock);
+
+       if (conf->pending_bio_list.head) {
+               struct bio *bio;
+               bio = bio_list_get(&conf->pending_bio_list);
+               blk_remove_plug(conf->mddev->queue);
+               spin_unlock_irq(&conf->device_lock);
+               /* flush any pending bitmap writes to
+                * disk before proceeding w/ I/O */
+               bitmap_unplug(conf->mddev->bitmap);
+
+               while (bio) { /* submit pending writes */
+                       struct bio *next = bio->bi_next;
+                       bio->bi_next = NULL;
+                       generic_make_request(bio);
+                       bio = next;
+               }
+               rv = 1;
+       } else
+               spin_unlock_irq(&conf->device_lock);
+       return rv;
+}
+
 /* Barriers....
  * Sometimes we need to suspend IO while we do something else,
  * either some resync/recovery, or reconfigure the array.
@@ -664,15 +708,23 @@ static void freeze_array(conf_t *conf)
        /* stop syncio and normal IO and wait for everything to
         * go quite.
         * We increment barrier and nr_waiting, and then
-        * wait until barrier+nr_pending match nr_queued+2
+        * wait until nr_pending match nr_queued+1
+        * This is called in the context of one normal IO request
+        * that has failed. Thus any sync request that might be pending
+        * will be blocked by nr_pending, and we need to wait for
+        * pending IO requests to complete or be queued for re-try.
+        * Thus the number queued (nr_queued) plus this request (1)
+        * must match the number of pending IOs (nr_pending) before
+        * we continue.
         */
        spin_lock_irq(&conf->resync_lock);
        conf->barrier++;
        conf->nr_waiting++;
        wait_event_lock_irq(conf->wait_barrier,
-                           conf->barrier+conf->nr_pending == conf->nr_queued+2,
+                           conf->nr_pending == conf->nr_queued+1,
                            conf->resync_lock,
-                           raid1_unplug(conf->mddev->queue));
+                           ({ flush_pending_writes(conf);
+                              raid1_unplug(conf->mddev->queue); }));
        spin_unlock_irq(&conf->resync_lock);
 }
 static void unfreeze_array(conf_t *conf)
@@ -691,13 +743,11 @@ static struct page **alloc_behind_pages(struct bio *bio)
 {
        int i;
        struct bio_vec *bvec;
-       struct page **pages = kmalloc(bio->bi_vcnt * sizeof(struct page *),
+       struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
                                        GFP_NOIO);
        if (unlikely(!pages))
                goto do_sync_io;
 
-       memset(pages, 0, bio->bi_vcnt * sizeof(struct page *));
-
        bio_for_each_segment(bvec, bio, i) {
                pages[i] = alloc_page(GFP_NOIO);
                if (unlikely(!pages[i]))
@@ -713,13 +763,13 @@ static struct page **alloc_behind_pages(struct bio *bio)
 do_sync_io:
        if (pages)
                for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
-                       __free_page(pages[i]);
+                       put_page(pages[i]);
        kfree(pages);
        PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
        return NULL;
 }
 
-static int make_request(request_queue_t *q, struct bio * bio)
+static int make_request(struct request_queue *q, struct bio * bio)
 {
        mddev_t *mddev = q->queuedata;
        conf_t *conf = mddev_to_conf(mddev);
@@ -727,30 +777,42 @@ static int make_request(request_queue_t *q, struct bio * bio)
        r1bio_t *r1_bio;
        struct bio *read_bio;
        int i, targets = 0, disks;
-       mdk_rdev_t *rdev;
-       struct bitmap *bitmap = mddev->bitmap;
+       struct bitmap *bitmap;
        unsigned long flags;
        struct bio_list bl;
        struct page **behind_pages = NULL;
        const int rw = bio_data_dir(bio);
-       int do_barriers;
-
-       if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
-               bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
-               return 0;
-       }
+       const int do_sync = bio_sync(bio);
+       int cpu, do_barriers;
+       mdk_rdev_t *blocked_rdev;
 
        /*
         * Register the new request and wait if the reconstruction
         * thread has put up a bar for new requests.
         * Continue immediately if no resync is active currently.
+        * We test barriers_work *after* md_write_start as md_write_start
+        * may cause the first superblock write, and that will check out
+        * if barriers work.
         */
+
        md_write_start(mddev, bio); /* wait on superblock update early */
 
+       if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
+               if (rw == WRITE)
+                       md_write_end(mddev);
+               bio_endio(bio, -EOPNOTSUPP);
+               return 0;
+       }
+
        wait_barrier(conf);
 
-       disk_stat_inc(mddev->gendisk, ios[rw]);
-       disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
+       bitmap = mddev->bitmap;
+
+       cpu = part_stat_lock();
+       part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
+       part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
+                     bio_sectors(bio));
+       part_stat_unlock();
 
        /*
         * make_request() can abort the operation when READA is being
@@ -787,7 +849,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
                read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
                read_bio->bi_bdev = mirror->rdev->bdev;
                read_bio->bi_end_io = raid1_end_read_request;
-               read_bio->bi_rw = READ;
+               read_bio->bi_rw = READ | do_sync;
                read_bio->bi_private = r1_bio;
 
                generic_make_request(read_bio);
@@ -809,13 +871,20 @@ static int make_request(request_queue_t *q, struct bio * bio)
        first = 0;
        }
 #endif
+ retry_write:
+       blocked_rdev = NULL;
        rcu_read_lock();
        for (i = 0;  i < disks; i++) {
-               if ((rdev=rcu_dereference(conf->mirrors[i].rdev)) != NULL &&
-                   !test_bit(Faulty, &rdev->flags)) {
+               mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
+               if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
+                       atomic_inc(&rdev->nr_pending);
+                       blocked_rdev = rdev;
+                       break;
+               }
+               if (rdev && !test_bit(Faulty, &rdev->flags)) {
                        atomic_inc(&rdev->nr_pending);
                        if (test_bit(Faulty, &rdev->flags)) {
-                               atomic_dec(&rdev->nr_pending);
+                               rdev_dec_pending(rdev, mddev);
                                r1_bio->bios[i] = NULL;
                        } else
                                r1_bio->bios[i] = bio;
@@ -825,6 +894,20 @@ static int make_request(request_queue_t *q, struct bio * bio)
        }
        rcu_read_unlock();
 
+       if (unlikely(blocked_rdev)) {
+               /* Wait for this device to become unblocked */
+               int j;
+
+               for (j = 0; j < i; j++)
+                       if (r1_bio->bios[j])
+                               rdev_dec_pending(conf->mirrors[j].rdev, mddev);
+
+               allow_barrier(conf);
+               md_wait_for_blocked_rdev(blocked_rdev, mddev);
+               wait_barrier(conf);
+               goto retry_write;
+       }
+
        BUG_ON(targets == 0); /* we never fail the last device */
 
        if (targets < conf->raid_disks) {
@@ -842,7 +925,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
        atomic_set(&r1_bio->remaining, 0);
        atomic_set(&r1_bio->behind_remaining, 0);
 
-       do_barriers = bio->bi_rw & BIO_RW_BARRIER;
+       do_barriers = bio_barrier(bio);
        if (do_barriers)
                set_bit(R1BIO_Barrier, &r1_bio->state);
 
@@ -858,7 +941,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
                mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
                mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
                mbio->bi_end_io = raid1_end_write_request;
-               mbio->bi_rw = WRITE | do_barriers;
+               mbio->bi_rw = WRITE | do_barriers | do_sync;
                mbio->bi_private = r1_bio;
 
                if (behind_pages) {
@@ -893,6 +976,11 @@ static int make_request(request_queue_t *q, struct bio * bio)
        blk_plug_device(mddev->queue);
        spin_unlock_irqrestore(&conf->device_lock, flags);
 
+       /* In case raid1d snuck into freeze_array */
+       wake_up(&conf->wait_barrier);
+
+       if (do_sync)
+               md_wakeup_thread(mddev->thread);
 #if 0
        while ((bio = bio_list_pop(&bl)) != NULL)
                generic_make_request(bio);
@@ -907,11 +995,14 @@ static void status(struct seq_file *seq, mddev_t *mddev)
        int i;
 
        seq_printf(seq, " [%d/%d] [", conf->raid_disks,
-                                               conf->working_disks);
-       for (i = 0; i < conf->raid_disks; i++)
+                  conf->raid_disks - mddev->degraded);
+       rcu_read_lock();
+       for (i = 0; i < conf->raid_disks; i++) {
+               mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
                seq_printf(seq, "%s",
-                             conf->mirrors[i].rdev &&
-                             test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
+                          rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
+       }
+       rcu_read_unlock();
        seq_printf(seq, "]");
 }
 
@@ -928,49 +1019,57 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev)
         * else mark the drive as failed
         */
        if (test_bit(In_sync, &rdev->flags)
-           && conf->working_disks == 1)
+           && (conf->raid_disks - mddev->degraded) == 1) {
                /*
                 * Don't fail the drive, act as though we were just a
-                * normal single drive
+                * normal single drive.
+                * However don't try a recovery from this drive as
+                * it is very likely to fail.
                 */
+               mddev->recovery_disabled = 1;
                return;
-       if (test_bit(In_sync, &rdev->flags)) {
+       }
+       if (test_and_clear_bit(In_sync, &rdev->flags)) {
+               unsigned long flags;
+               spin_lock_irqsave(&conf->device_lock, flags);
                mddev->degraded++;
-               conf->working_disks--;
+               set_bit(Faulty, &rdev->flags);
+               spin_unlock_irqrestore(&conf->device_lock, flags);
                /*
                 * if recovery is running, make sure it aborts.
                 */
-               set_bit(MD_RECOVERY_ERR, &mddev->recovery);
-       }
-       clear_bit(In_sync, &rdev->flags);
-       set_bit(Faulty, &rdev->flags);
-       mddev->sb_dirty = 1;
-       printk(KERN_ALERT "raid1: Disk failure on %s, disabling device. \n"
-               "       Operation continuing on %d devices\n",
-               bdevname(rdev->bdev,b), conf->working_disks);
+               set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+       } else
+               set_bit(Faulty, &rdev->flags);
+       set_bit(MD_CHANGE_DEVS, &mddev->flags);
+       printk(KERN_ALERT "raid1: Disk failure on %s, disabling device.\n"
+               "raid1: Operation continuing on %d devices.\n",
+               bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
 }
 
 static void print_conf(conf_t *conf)
 {
        int i;
-       mirror_info_t *tmp;
 
        printk("RAID1 conf printout:\n");
        if (!conf) {
                printk("(!conf)\n");
                return;
        }
-       printk(" --- wd:%d rd:%d\n", conf->working_disks,
+       printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
                conf->raid_disks);
 
+       rcu_read_lock();
        for (i = 0; i < conf->raid_disks; i++) {
                char b[BDEVNAME_SIZE];
-               tmp = conf->mirrors + i;
-               if (tmp->rdev)
+               mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
+               if (rdev)
                        printk(" disk %d, wo:%d, o:%d, dev:%s\n",
-                               i, !test_bit(In_sync, &tmp->rdev->flags), !test_bit(Faulty, &tmp->rdev->flags),
-                               bdevname(tmp->rdev->bdev,b));
+                              i, !test_bit(In_sync, &rdev->flags),
+                              !test_bit(Faulty, &rdev->flags),
+                              bdevname(rdev->bdev,b));
        }
+       rcu_read_unlock();
 }
 
 static void close_sync(conf_t *conf)
@@ -986,20 +1085,21 @@ static int raid1_spare_active(mddev_t *mddev)
 {
        int i;
        conf_t *conf = mddev->private;
-       mirror_info_t *tmp;
 
        /*
         * Find all failed disks within the RAID1 configuration 
-        * and mark them readable
+        * and mark them readable.
+        * Called under mddev lock, so rcu protection not needed.
         */
        for (i = 0; i < conf->raid_disks; i++) {
-               tmp = conf->mirrors + i;
-               if (tmp->rdev 
-                   && !test_bit(Faulty, &tmp->rdev->flags)
-                   && !test_bit(In_sync, &tmp->rdev->flags)) {
-                       conf->working_disks++;
+               mdk_rdev_t *rdev = conf->mirrors[i].rdev;
+               if (rdev
+                   && !test_bit(Faulty, &rdev->flags)
+                   && !test_and_set_bit(In_sync, &rdev->flags)) {
+                       unsigned long flags;
+                       spin_lock_irqsave(&conf->device_lock, flags);
                        mddev->degraded--;
-                       set_bit(In_sync, &tmp->rdev->flags);
+                       spin_unlock_irqrestore(&conf->device_lock, flags);
                }
        }
 
@@ -1011,11 +1111,16 @@ static int raid1_spare_active(mddev_t *mddev)
 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
        conf_t *conf = mddev->private;
-       int found = 0;
+       int err = -EEXIST;
        int mirror = 0;
        mirror_info_t *p;
+       int first = 0;
+       int last = mddev->raid_disks - 1;
+
+       if (rdev->raid_disk >= 0)
+               first = last = rdev->raid_disk;
 
-       for (mirror=0; mirror < mddev->raid_disks; mirror++)
+       for (mirror = first; mirror <= last; mirror++)
                if ( !(p=conf->mirrors+mirror)->rdev) {
 
                        blk_queue_stack_limits(mddev->queue,
@@ -1030,7 +1135,7 @@ static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 
                        p->head_position = 0;
                        rdev->raid_disk = mirror;
-                       found = 1;
+                       err = 0;
                        /* As all devices are equivalent, we don't need a full recovery
                         * if this was recently any drive of the array
                         */
@@ -1041,7 +1146,7 @@ static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                }
 
        print_conf(conf);
-       return found;
+       return err;
 }
 
 static int raid1_remove_disk(mddev_t *mddev, int number)
@@ -1059,6 +1164,14 @@ static int raid1_remove_disk(mddev_t *mddev, int number)
                        err = -EBUSY;
                        goto abort;
                }
+               /* Only remove non-faulty devices is recovery
+                * is not possible.
+                */
+               if (!test_bit(Faulty, &rdev->flags) &&
+                   mddev->degraded < conf->raid_disks) {
+                       err = -EBUSY;
+                       goto abort;
+               }
                p->rdev = NULL;
                synchronize_rcu();
                if (atomic_read(&rdev->nr_pending)) {
@@ -1074,16 +1187,16 @@ abort:
 }
 
 
-static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
+static void end_sync_read(struct bio *bio, int error)
 {
        r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
+       int i;
 
-       if (bio->bi_size)
-               return 1;
-
-       if (r1_bio->bios[r1_bio->read_disk] != bio)
-               BUG();
-       update_head_pos(r1_bio->read_disk, r1_bio);
+       for (i=r1_bio->mddev->raid_disks; i--; )
+               if (r1_bio->bios[i] == bio)
+                       break;
+       BUG_ON(i < 0);
+       update_head_pos(i, r1_bio);
        /*
         * we have read a block, now it needs to be re-written,
         * or re-read if the read failed.
@@ -1091,11 +1204,12 @@ static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
         */
        if (test_bit(BIO_UPTODATE, &bio->bi_flags))
                set_bit(R1BIO_Uptodate, &r1_bio->state);
-       reschedule_retry(r1_bio);
-       return 0;
+
+       if (atomic_dec_and_test(&r1_bio->remaining))
+               reschedule_retry(r1_bio);
 }
 
-static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
+static void end_sync_write(struct bio *bio, int error)
 {
        int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
        r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
@@ -1104,24 +1218,32 @@ static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
        int i;
        int mirror=0;
 
-       if (bio->bi_size)
-               return 1;
-
        for (i = 0; i < conf->raid_disks; i++)
                if (r1_bio->bios[i] == bio) {
                        mirror = i;
                        break;
                }
-       if (!uptodate)
+       if (!uptodate) {
+               int sync_blocks = 0;
+               sector_t s = r1_bio->sector;
+               long sectors_to_go = r1_bio->sectors;
+               /* make sure these bits doesn't get cleared. */
+               do {
+                       bitmap_end_sync(mddev->bitmap, s,
+                                       &sync_blocks, 1);
+                       s += sync_blocks;
+                       sectors_to_go -= sync_blocks;
+               } while (sectors_to_go > 0);
                md_error(mddev, conf->mirrors[mirror].rdev);
+       }
 
        update_head_pos(mirror, r1_bio);
 
        if (atomic_dec_and_test(&r1_bio->remaining)) {
-               md_done_sync(mddev, r1_bio->sectors, uptodate);
+               sector_t s = r1_bio->sectors;
                put_buf(r1_bio);
+               md_done_sync(mddev, s, uptodate);
        }
-       return 0;
 }
 
 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
@@ -1134,14 +1256,93 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
        bio = r1_bio->bios[r1_bio->read_disk];
 
 
-       /*
-        * schedule writes
-        */
+       if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
+               /* We have read all readable devices.  If we haven't
+                * got the block, then there is no hope left.
+                * If we have, then we want to do a comparison
+                * and skip the write if everything is the same.
+                * If any blocks failed to read, then we need to
+                * attempt an over-write
+                */
+               int primary;
+               if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
+                       for (i=0; i<mddev->raid_disks; i++)
+                               if (r1_bio->bios[i]->bi_end_io == end_sync_read)
+                                       md_error(mddev, conf->mirrors[i].rdev);
+
+                       md_done_sync(mddev, r1_bio->sectors, 1);
+                       put_buf(r1_bio);
+                       return;
+               }
+               for (primary=0; primary<mddev->raid_disks; primary++)
+                       if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
+                           test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
+                               r1_bio->bios[primary]->bi_end_io = NULL;
+                               rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
+                               break;
+                       }
+               r1_bio->read_disk = primary;
+               for (i=0; i<mddev->raid_disks; i++)
+                       if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
+                               int j;
+                               int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
+                               struct bio *pbio = r1_bio->bios[primary];
+                               struct bio *sbio = r1_bio->bios[i];
+
+                               if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
+                                       for (j = vcnt; j-- ; ) {
+                                               struct page *p, *s;
+                                               p = pbio->bi_io_vec[j].bv_page;
+                                               s = sbio->bi_io_vec[j].bv_page;
+                                               if (memcmp(page_address(p),
+                                                          page_address(s),
+                                                          PAGE_SIZE))
+                                                       break;
+                                       }
+                               } else
+                                       j = 0;
+                               if (j >= 0)
+                                       mddev->resync_mismatches += r1_bio->sectors;
+                               if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
+                                             && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
+                                       sbio->bi_end_io = NULL;
+                                       rdev_dec_pending(conf->mirrors[i].rdev, mddev);
+                               } else {
+                                       /* fixup the bio for reuse */
+                                       int size;
+                                       sbio->bi_vcnt = vcnt;
+                                       sbio->bi_size = r1_bio->sectors << 9;
+                                       sbio->bi_idx = 0;
+                                       sbio->bi_phys_segments = 0;
+                                       sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
+                                       sbio->bi_flags |= 1 << BIO_UPTODATE;
+                                       sbio->bi_next = NULL;
+                                       sbio->bi_sector = r1_bio->sector +
+                                               conf->mirrors[i].rdev->data_offset;
+                                       sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
+                                       size = sbio->bi_size;
+                                       for (j = 0; j < vcnt ; j++) {
+                                               struct bio_vec *bi;
+                                               bi = &sbio->bi_io_vec[j];
+                                               bi->bv_offset = 0;
+                                               if (size > PAGE_SIZE)
+                                                       bi->bv_len = PAGE_SIZE;
+                                               else
+                                                       bi->bv_len = size;
+                                               size -= PAGE_SIZE;
+                                               memcpy(page_address(bi->bv_page),
+                                                      page_address(pbio->bi_io_vec[j].bv_page),
+                                                      PAGE_SIZE);
+                                       }
+
+                               }
+                       }
+       }
        if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
                /* ouch - failed to read all of that.
                 * Try some synchronous reads of other devices to get
                 * good data, much like with normal read errors.  Only
-                * read into the pages we already have so they we don't
+                * read into the pages we already have so we don't
                 * need to re-issue the read request.
                 * We don't need to freeze the array, because being in an
                 * active sync request, there is no normal IO, and
@@ -1161,6 +1362,10 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
                                s = PAGE_SIZE >> 9;
                        do {
                                if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
+                                       /* No rcu protection needed here devices
+                                        * can only be removed when no resync is
+                                        * active, and resync is currently active
+                                        */
                                        rdev = conf->mirrors[d].rdev;
                                        if (sync_page_io(rdev->bdev,
                                                         sect + rdev->data_offset,
@@ -1177,6 +1382,7 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
                        } while (!success && d != r1_bio->read_disk);
 
                        if (success) {
+                               int start = d;
                                /* write it back and re-read */
                                set_bit(R1BIO_Uptodate, &r1_bio->state);
                                while (d != r1_bio->read_disk) {
@@ -1186,18 +1392,28 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
                                        if (r1_bio->bios[d]->bi_end_io != end_sync_read)
                                                continue;
                                        rdev = conf->mirrors[d].rdev;
+                                       atomic_add(s, &rdev->corrected_errors);
                                        if (sync_page_io(rdev->bdev,
                                                         sect + rdev->data_offset,
                                                         s<<9,
                                                         bio->bi_io_vec[idx].bv_page,
-                                                        WRITE) == 0 ||
-                                           sync_page_io(rdev->bdev,
+                                                        WRITE) == 0)
+                                               md_error(mddev, rdev);
+                               }
+                               d = start;
+                               while (d != r1_bio->read_disk) {
+                                       if (d == 0)
+                                               d = conf->raid_disks;
+                                       d--;
+                                       if (r1_bio->bios[d]->bi_end_io != end_sync_read)
+                                               continue;
+                                       rdev = conf->mirrors[d].rdev;
+                                       if (sync_page_io(rdev->bdev,
                                                         sect + rdev->data_offset,
                                                         s<<9,
                                                         bio->bi_io_vec[idx].bv_page,
-                                                        READ) == 0) {
+                                                        READ) == 0)
                                                md_error(mddev, rdev);
-                                       }
                                }
                        } else {
                                char b[BDEVNAME_SIZE];
@@ -1216,6 +1432,10 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
                        idx ++;
                }
        }
+
+       /*
+        * schedule writes
+        */
        atomic_set(&r1_bio->remaining, 1);
        for (i = 0; i < disks ; i++) {
                wbio = r1_bio->bios[i];
@@ -1248,6 +1468,95 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
  *     3.      Performs writes following reads for array syncronising.
  */
 
+static void fix_read_error(conf_t *conf, int read_disk,
+                          sector_t sect, int sectors)
+{
+       mddev_t *mddev = conf->mddev;
+       while(sectors) {
+               int s = sectors;
+               int d = read_disk;
+               int success = 0;
+               int start;
+               mdk_rdev_t *rdev;
+
+               if (s > (PAGE_SIZE>>9))
+                       s = PAGE_SIZE >> 9;
+
+               do {
+                       /* Note: no rcu protection needed here
+                        * as this is synchronous in the raid1d thread
+                        * which is the thread that might remove
+                        * a device.  If raid1d ever becomes multi-threaded....
+                        */
+                       rdev = conf->mirrors[d].rdev;
+                       if (rdev &&
+                           test_bit(In_sync, &rdev->flags) &&
+                           sync_page_io(rdev->bdev,
+                                        sect + rdev->data_offset,
+                                        s<<9,
+                                        conf->tmppage, READ))
+                               success = 1;
+                       else {
+                               d++;
+                               if (d == conf->raid_disks)
+                                       d = 0;
+                       }
+               } while (!success && d != read_disk);
+
+               if (!success) {
+                       /* Cannot read from anywhere -- bye bye array */
+                       md_error(mddev, conf->mirrors[read_disk].rdev);
+                       break;
+               }
+               /* write it back and re-read */
+               start = d;
+               while (d != read_disk) {
+                       if (d==0)
+                               d = conf->raid_disks;
+                       d--;
+                       rdev = conf->mirrors[d].rdev;
+                       if (rdev &&
+                           test_bit(In_sync, &rdev->flags)) {
+                               if (sync_page_io(rdev->bdev,
+                                                sect + rdev->data_offset,
+                                                s<<9, conf->tmppage, WRITE)
+                                   == 0)
+                                       /* Well, this device is dead */
+                                       md_error(mddev, rdev);
+                       }
+               }
+               d = start;
+               while (d != read_disk) {
+                       char b[BDEVNAME_SIZE];
+                       if (d==0)
+                               d = conf->raid_disks;
+                       d--;
+                       rdev = conf->mirrors[d].rdev;
+                       if (rdev &&
+                           test_bit(In_sync, &rdev->flags)) {
+                               if (sync_page_io(rdev->bdev,
+                                                sect + rdev->data_offset,
+                                                s<<9, conf->tmppage, READ)
+                                   == 0)
+                                       /* Well, this device is dead */
+                                       md_error(mddev, rdev);
+                               else {
+                                       atomic_add(s, &rdev->corrected_errors);
+                                       printk(KERN_INFO
+                                              "raid1:%s: read error corrected "
+                                              "(%d sectors at %llu on %s)\n",
+                                              mdname(mddev), s,
+                                              (unsigned long long)(sect +
+                                                  rdev->data_offset),
+                                              bdevname(rdev->bdev, b));
+                               }
+                       }
+               }
+               sectors -= s;
+               sect += s;
+       }
+}
+
 static void raid1d(mddev_t *mddev)
 {
        r1bio_t *r1_bio;
@@ -1262,29 +1571,14 @@ static void raid1d(mddev_t *mddev)
        
        for (;;) {
                char b[BDEVNAME_SIZE];
-               spin_lock_irqsave(&conf->device_lock, flags);
-
-               if (conf->pending_bio_list.head) {
-                       bio = bio_list_get(&conf->pending_bio_list);
-                       blk_remove_plug(mddev->queue);
-                       spin_unlock_irqrestore(&conf->device_lock, flags);
-                       /* flush any pending bitmap writes to disk before proceeding w/ I/O */
-                       if (bitmap_unplug(mddev->bitmap) != 0)
-                               printk("%s: bitmap file write failed!\n", mdname(mddev));
 
-                       while (bio) { /* submit pending writes */
-                               struct bio *next = bio->bi_next;
-                               bio->bi_next = NULL;
-                               generic_make_request(bio);
-                               bio = next;
-                       }
-                       unplug = 1;
-
-                       continue;
-               }
+               unplug += flush_pending_writes(conf);
 
-               if (list_empty(head))
+               spin_lock_irqsave(&conf->device_lock, flags);
+               if (list_empty(head)) {
+                       spin_unlock_irqrestore(&conf->device_lock, flags);
                        break;
+               }
                r1_bio = list_entry(head->prev, r1bio_t, retry_list);
                list_del(head->prev);
                conf->nr_queued--;
@@ -1297,15 +1591,20 @@ static void raid1d(mddev_t *mddev)
                        unplug = 1;
                } else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
                        /* some requests in the r1bio were BIO_RW_BARRIER
-                        * requests which failed with -ENOTSUPP.  Hohumm..
+                        * requests which failed with -EOPNOTSUPP.  Hohumm..
                         * Better resubmit without the barrier.
                         * We know which devices to resubmit for, because
                         * all others have had their bios[] entry cleared.
+                        * We already have a nr_pending reference on these rdevs.
                         */
                        int i;
+                       const int do_sync = bio_sync(r1_bio->master_bio);
                        clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
                        clear_bit(R1BIO_Barrier, &r1_bio->state);
                        for (i=0; i < conf->raid_disks; i++)
+                               if (r1_bio->bios[i])
+                                       atomic_inc(&r1_bio->remaining);
+                       for (i=0; i < conf->raid_disks; i++)
                                if (r1_bio->bios[i]) {
                                        struct bio_vec *bvec;
                                        int j;
@@ -1320,7 +1619,7 @@ static void raid1d(mddev_t *mddev)
                                                conf->mirrors[i].rdev->data_offset;
                                        bio->bi_bdev = conf->mirrors[i].rdev->bdev;
                                        bio->bi_end_io = raid1_end_write_request;
-                                       bio->bi_rw = WRITE;
+                                       bio->bi_rw = WRITE | do_sync;
                                        bio->bi_private = r1_bio;
                                        r1_bio->bios[i] = bio;
                                        generic_make_request(bio);
@@ -1336,72 +1635,24 @@ static void raid1d(mddev_t *mddev)
                         * This is all done synchronously while the array is
                         * frozen
                         */
-                       sector_t sect = r1_bio->sector;
-                       int sectors = r1_bio->sectors;
-                       freeze_array(conf);
-                       if (mddev->ro == 0) while(sectors) {
-                               int s = sectors;
-                               int d = r1_bio->read_disk;
-                               int success = 0;
-
-                               if (s > (PAGE_SIZE>>9))
-                                       s = PAGE_SIZE >> 9;
-
-                               do {
-                                       rdev = conf->mirrors[d].rdev;
-                                       if (rdev &&
-                                           test_bit(In_sync, &rdev->flags) &&
-                                           sync_page_io(rdev->bdev,
-                                                        sect + rdev->data_offset,
-                                                        s<<9,
-                                                        conf->tmppage, READ))
-                                               success = 1;
-                                       else {
-                                               d++;
-                                               if (d == conf->raid_disks)
-                                                       d = 0;
-                                       }
-                               } while (!success && d != r1_bio->read_disk);
-
-                               if (success) {
-                                       /* write it back and re-read */
-                                       while (d != r1_bio->read_disk) {
-                                               if (d==0)
-                                                       d = conf->raid_disks;
-                                               d--;
-                                               rdev = conf->mirrors[d].rdev;
-                                               if (rdev &&
-                                                   test_bit(In_sync, &rdev->flags)) {
-                                                       if (sync_page_io(rdev->bdev,
-                                                                        sect + rdev->data_offset,
-                                                                        s<<9, conf->tmppage, WRITE) == 0 ||
-                                                           sync_page_io(rdev->bdev,
-                                                                        sect + rdev->data_offset,
-                                                                        s<<9, conf->tmppage, READ) == 0) {
-                                                               /* Well, this device is dead */
-                                                               md_error(mddev, rdev);
-                                                       }
-                                               }
-                                       }
-                               } else {
-                                       /* Cannot read from anywhere -- bye bye array */
-                                       md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
-                                       break;
-                               }
-                               sectors -= s;
-                               sect += s;
+                       if (mddev->ro == 0) {
+                               freeze_array(conf);
+                               fix_read_error(conf, r1_bio->read_disk,
+                                              r1_bio->sector,
+                                              r1_bio->sectors);
+                               unfreeze_array(conf);
                        }
 
-                       unfreeze_array(conf);
-
                        bio = r1_bio->bios[r1_bio->read_disk];
-                       if ((disk=read_balance(conf, r1_bio)) == -1) {
+                       if ((disk=read_balance(conf, r1_bio)) == -1 ||
+                           disk == r1_bio->read_disk) {
                                printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
                                       " read error for block %llu\n",
                                       bdevname(bio->bi_bdev,b),
                                       (unsigned long long)r1_bio->sector);
                                raid_end_bio_io(r1_bio);
                        } else {
+                               const int do_sync = bio_sync(r1_bio->master_bio);
                                r1_bio->bios[r1_bio->read_disk] =
                                        mddev->ro ? IO_BLOCKED : NULL;
                                r1_bio->read_disk = disk;
@@ -1417,14 +1668,13 @@ static void raid1d(mddev_t *mddev)
                                bio->bi_sector = r1_bio->sector + rdev->data_offset;
                                bio->bi_bdev = rdev->bdev;
                                bio->bi_end_io = raid1_end_read_request;
-                               bio->bi_rw = READ;
+                               bio->bi_rw = READ | do_sync;
                                bio->bi_private = r1_bio;
                                unplug = 1;
                                generic_make_request(bio);
                        }
                }
        }
-       spin_unlock_irqrestore(&conf->device_lock, flags);
        if (unplug)
                unplug_slaves(mddev);
 }
@@ -1435,8 +1685,7 @@ static int init_resync(conf_t *conf)
        int buffs;
 
        buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
-       if (conf->r1buf_pool)
-               BUG();
+       BUG_ON(conf->r1buf_pool);
        conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
                                          conf->poolinfo);
        if (!conf->r1buf_pool)
@@ -1495,6 +1744,13 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
                return 0;
        }
 
+       if (mddev->bitmap == NULL &&
+           mddev->recovery_cp == MaxSector &&
+           !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
+           conf->fullsync == 0) {
+               *skipped = 1;
+               return max_sector - sector_nr;
+       }
        /* before building a request, check if we can skip these blocks..
         * This call the bitmap_start_sync doesn't actually record anything
         */
@@ -1512,6 +1768,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
        if (!go_faster && conf->nr_waiting)
                msleep_interruptible(1000);
 
+       bitmap_cond_end_sync(mddev->bitmap, sector_nr);
        raise_barrier(conf);
 
        conf->next_resync = sector_nr;
@@ -1539,11 +1796,10 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
                /* take from bio_init */
                bio->bi_next = NULL;
                bio->bi_flags |= 1 << BIO_UPTODATE;
-               bio->bi_rw = 0;
+               bio->bi_rw = READ;
                bio->bi_vcnt = 0;
                bio->bi_idx = 0;
                bio->bi_phys_segments = 0;
-               bio->bi_hw_segments = 0;
                bio->bi_size = 0;
                bio->bi_end_io = NULL;
                bio->bi_private = NULL;
@@ -1594,6 +1850,8 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
                return rv;
        }
 
+       if (max_sector > mddev->resync_max)
+               max_sector = mddev->resync_max; /* Don't do IO beyond here */
        nr_sectors = 0;
        sync_blocks = 0;
        do {
@@ -1609,8 +1867,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
                            !conf->fullsync &&
                            !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
                                break;
-                       if (sync_blocks < (PAGE_SIZE>>9))
-                               BUG();
+                       BUG_ON(sync_blocks < (PAGE_SIZE>>9));
                        if (len > (sync_blocks<<9))
                                len = sync_blocks<<9;
                }
@@ -1618,10 +1875,10 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
                for (i=0 ; i < conf->raid_disks; i++) {
                        bio = r1_bio->bios[i];
                        if (bio->bi_end_io) {
-                               page = r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page;
+                               page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
                                if (bio_add_page(bio, page, len, 0) == 0) {
                                        /* stop here */
-                                       r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page = page;
+                                       bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
                                        while (i > 0) {
                                                i--;
                                                bio = r1_bio->bios[i];
@@ -1641,13 +1898,27 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
                sync_blocks -= (len>>9);
        } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
  bio_full:
-       bio = r1_bio->bios[r1_bio->read_disk];
        r1_bio->sectors = nr_sectors;
 
-       md_sync_acct(conf->mirrors[r1_bio->read_disk].rdev->bdev, nr_sectors);
-
-       generic_make_request(bio);
+       /* For a user-requested sync, we read all readable devices and do a
+        * compare
+        */
+       if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
+               atomic_set(&r1_bio->remaining, read_targets);
+               for (i=0; i<conf->raid_disks; i++) {
+                       bio = r1_bio->bios[i];
+                       if (bio->bi_end_io == end_sync_read) {
+                               md_sync_acct(bio->bi_bdev, nr_sectors);
+                               generic_make_request(bio);
+                       }
+               }
+       } else {
+               atomic_set(&r1_bio->remaining, 1);
+               bio = r1_bio->bios[r1_bio->read_disk];
+               md_sync_acct(bio->bi_bdev, nr_sectors);
+               generic_make_request(bio);
 
+       }
        return nr_sectors;
 }
 
@@ -1657,31 +1928,32 @@ static int run(mddev_t *mddev)
        int i, j, disk_idx;
        mirror_info_t *disk;
        mdk_rdev_t *rdev;
-       struct list_head *tmp;
 
        if (mddev->level != 1) {
                printk("raid1: %s: raid level not set to mirroring (%d)\n",
                       mdname(mddev), mddev->level);
                goto out;
        }
+       if (mddev->reshape_position != MaxSector) {
+               printk("raid1: %s: reshape_position set but not supported\n",
+                      mdname(mddev));
+               goto out;
+       }
        /*
         * copy the already verified devices into our private RAID1
         * bookkeeping area. [whatever we allocate in run(),
         * should be freed in stop()]
         */
-       conf = kmalloc(sizeof(conf_t), GFP_KERNEL);
+       conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
        mddev->private = conf;
        if (!conf)
                goto out_no_mem;
 
-       memset(conf, 0, sizeof(*conf));
-       conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks, 
+       conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
                                 GFP_KERNEL);
        if (!conf->mirrors)
                goto out_no_mem;
 
-       memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks);
-
        conf->tmppage = alloc_page(GFP_KERNEL);
        if (!conf->tmppage)
                goto out_no_mem;
@@ -1697,7 +1969,10 @@ static int run(mddev_t *mddev)
        if (!conf->r1bio_pool)
                goto out_no_mem;
 
-       ITERATE_RDEV(mddev, rdev, tmp) {
+       spin_lock_init(&conf->device_lock);
+       mddev->queue->queue_lock = &conf->device_lock;
+
+       list_for_each_entry(rdev, &mddev->disks, same_set) {
                disk_idx = rdev->raid_disk;
                if (disk_idx >= mddev->raid_disks
                    || disk_idx < 0)
@@ -1717,15 +1992,10 @@ static int run(mddev_t *mddev)
                        blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
 
                disk->head_position = 0;
-               if (!test_bit(Faulty, &rdev->flags) && test_bit(In_sync, &rdev->flags))
-                       conf->working_disks++;
        }
        conf->raid_disks = mddev->raid_disks;
        conf->mddev = mddev;
-       spin_lock_init(&conf->device_lock);
        INIT_LIST_HEAD(&conf->retry_list);
-       if (conf->working_disks == 1)
-               mddev->recovery_cp = MaxSector;
 
        spin_lock_init(&conf->resync_lock);
        init_waitqueue_head(&conf->wait_barrier);
@@ -1733,22 +2003,27 @@ static int run(mddev_t *mddev)
        bio_list_init(&conf->pending_bio_list);
        bio_list_init(&conf->flushing_bio_list);
 
-       if (!conf->working_disks) {
-               printk(KERN_ERR "raid1: no operational mirrors for %s\n",
-                       mdname(mddev));
-               goto out_free_conf;
-       }
 
        mddev->degraded = 0;
        for (i = 0; i < conf->raid_disks; i++) {
 
                disk = conf->mirrors + i;
 
-               if (!disk->rdev) {
+               if (!disk->rdev ||
+                   !test_bit(In_sync, &disk->rdev->flags)) {
                        disk->head_position = 0;
                        mddev->degraded++;
+                       if (disk->rdev)
+                               conf->fullsync = 1;
                }
        }
+       if (mddev->degraded == conf->raid_disks) {
+               printk(KERN_ERR "raid1: no operational mirrors for %s\n",
+                       mdname(mddev));
+               goto out_free_conf;
+       }
+       if (conf->raid_disks - mddev->degraded == 1)
+               mddev->recovery_cp = MaxSector;
 
        /*
         * find the first working one and use it as a starting point
@@ -1776,10 +2051,11 @@ static int run(mddev_t *mddev)
        /*
         * Ok, everything is just fine now
         */
-       mddev->array_size = mddev->size;
+       mddev->array_sectors = mddev->size * 2;
 
        mddev->queue->unplug_fn = raid1_unplug;
-       mddev->queue->issue_flush_fn = raid1_issue_flush;
+       mddev->queue->backing_dev_info.congested_fn = raid1_congested;
+       mddev->queue->backing_dev_info.congested_data = mddev;
 
        return 0;
 
@@ -1792,7 +2068,7 @@ out_free_conf:
                if (conf->r1bio_pool)
                        mempool_destroy(conf->r1bio_pool);
                kfree(conf->mirrors);
-               __free_page(conf->tmppage);
+               safe_put_page(conf->tmppage);
                kfree(conf->poolinfo);
                kfree(conf);
                mddev->private = NULL;
@@ -1837,19 +2113,20 @@ static int raid1_resize(mddev_t *mddev, sector_t sectors)
         * any io in the removed space completes, but it hardly seems
         * worth it.
         */
-       mddev->array_size = sectors>>1;
-       set_capacity(mddev->gendisk, mddev->array_size << 1);
+       mddev->array_sectors = sectors;
+       set_capacity(mddev->gendisk, mddev->array_sectors);
        mddev->changed = 1;
-       if (mddev->array_size > mddev->size && mddev->recovery_cp == MaxSector) {
+       if (mddev->array_sectors / 2 > mddev->size &&
+           mddev->recovery_cp == MaxSector) {
                mddev->recovery_cp = mddev->size << 1;
                set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
        }
-       mddev->size = mddev->array_size;
+       mddev->size = mddev->array_sectors / 2;
        mddev->resync_max_sectors = sectors;
        return 0;
 }
 
-static int raid1_reshape(mddev_t *mddev, int raid_disks)
+static int raid1_reshape(mddev_t *mddev)
 {
        /* We need to:
         * 1/ resize the r1bio_pool
@@ -1866,9 +2143,25 @@ static int raid1_reshape(mddev_t *mddev, int raid_disks)
        struct pool_info *newpoolinfo;
        mirror_info_t *newmirrors;
        conf_t *conf = mddev_to_conf(mddev);
-       int cnt;
+       int cnt, raid_disks;
+       unsigned long flags;
+       int d, d2, err;
+
+       /* Cannot change chunk_size, layout, or level */
+       if (mddev->chunk_size != mddev->new_chunk ||
+           mddev->layout != mddev->new_layout ||
+           mddev->level != mddev->new_level) {
+               mddev->new_chunk = mddev->chunk_size;
+               mddev->new_layout = mddev->layout;
+               mddev->new_level = mddev->level;
+               return -EINVAL;
+       }
+
+       err = md_allow_write(mddev);
+       if (err)
+               return err;
 
-       int d, d2;
+       raid_disks = mddev->raid_disks + mddev->delta_disks;
 
        if (raid_disks < conf->raid_disks) {
                cnt=0;
@@ -1891,13 +2184,12 @@ static int raid1_reshape(mddev_t *mddev, int raid_disks)
                kfree(newpoolinfo);
                return -ENOMEM;
        }
-       newmirrors = kmalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
+       newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
        if (!newmirrors) {
                kfree(newpoolinfo);
                mempool_destroy(newpool);
                return -ENOMEM;
        }
-       memset(newmirrors, 0, sizeof(struct mirror_info)*raid_disks);
 
        raise_barrier(conf);
 
@@ -1905,18 +2197,35 @@ static int raid1_reshape(mddev_t *mddev, int raid_disks)
        oldpool = conf->r1bio_pool;
        conf->r1bio_pool = newpool;
 
-       for (d=d2=0; d < conf->raid_disks; d++)
-               if (conf->mirrors[d].rdev) {
-                       conf->mirrors[d].rdev->raid_disk = d2;
-                       newmirrors[d2++].rdev = conf->mirrors[d].rdev;
+       for (d = d2 = 0; d < conf->raid_disks; d++) {
+               mdk_rdev_t *rdev = conf->mirrors[d].rdev;
+               if (rdev && rdev->raid_disk != d2) {
+                       char nm[20];
+                       sprintf(nm, "rd%d", rdev->raid_disk);
+                       sysfs_remove_link(&mddev->kobj, nm);
+                       rdev->raid_disk = d2;
+                       sprintf(nm, "rd%d", rdev->raid_disk);
+                       sysfs_remove_link(&mddev->kobj, nm);
+                       if (sysfs_create_link(&mddev->kobj,
+                                             &rdev->kobj, nm))
+                               printk(KERN_WARNING
+                                      "md/raid1: cannot register "
+                                      "%s for %s\n",
+                                      nm, mdname(mddev));
                }
+               if (rdev)
+                       newmirrors[d2++].rdev = rdev;
+       }
        kfree(conf->mirrors);
        conf->mirrors = newmirrors;
        kfree(conf->poolinfo);
        conf->poolinfo = newpoolinfo;
 
+       spin_lock_irqsave(&conf->device_lock, flags);
        mddev->degraded += (raid_disks - conf->raid_disks);
+       spin_unlock_irqrestore(&conf->device_lock, flags);
        conf->raid_disks = mddev->raid_disks = raid_disks;
+       mddev->delta_disks = 0;
 
        conf->last_used = 0; /* just make sure it is in-range */
        lower_barrier(conf);
@@ -1943,9 +2252,10 @@ static void raid1_quiesce(mddev_t *mddev, int state)
 }
 
 
-static mdk_personality_t raid1_personality =
+static struct mdk_personality raid1_personality =
 {
        .name           = "raid1",
+       .level          = 1,
        .owner          = THIS_MODULE,
        .make_request   = make_request,
        .run            = run,
@@ -1957,21 +2267,23 @@ static mdk_personality_t raid1_personality =
        .spare_active   = raid1_spare_active,
        .sync_request   = sync_request,
        .resize         = raid1_resize,
-       .reshape        = raid1_reshape,
+       .check_reshape  = raid1_reshape,
        .quiesce        = raid1_quiesce,
 };
 
 static int __init raid_init(void)
 {
-       return register_md_personality(RAID1, &raid1_personality);
+       return register_md_personality(&raid1_personality);
 }
 
 static void raid_exit(void)
 {
-       unregister_md_personality(RAID1);
+       unregister_md_personality(&raid1_personality);
 }
 
 module_init(raid_init);
 module_exit(raid_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-3"); /* RAID1 */
+MODULE_ALIAS("md-raid1");
+MODULE_ALIAS("md-level-1");