Merge ../torvalds-2.6/

1 files changed, 213 insertions, 135 deletions

diff --git a/drivers/md/raid6main.c b/drivers/md/raid6main.c
index 0000d162d198..8c823d686a60 100644
--- a/drivers/md/raid6main.c
+++ b/drivers/md/raid6main.c
@@ -40,12 +40,10 @@
 #define STRIPE_SHIFT            (PAGE_SHIFT - 9)
 #define STRIPE_SECTORS          (STRIPE_SIZE>>9)
 #define IO_THRESHOLD            1
-#define HASH_PAGES              1
-#define HASH_PAGES_ORDER        0
-#define NR_HASH                 (HASH_PAGES * PAGE_SIZE / sizeof(struct stripe_head *))
+#define NR_HASH                 (PAGE_SIZE / sizeof(struct hlist_head))
 #define HASH_MASK               (NR_HASH - 1)
 
-#define stripe_hash(conf, sect) ((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK])
+#define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
 
 /* bio's attached to a stripe+device for I/O are linked together in bi_sector
  * order without overlap.  There may be several bio's per stripe+device, and
@@ -132,29 +130,21 @@ static void release_stripe(struct stripe_head *sh)
         spin_unlock_irqrestore(&conf->device_lock, flags);
 }
 
-static void remove_hash(struct stripe_head *sh)
+static inline void remove_hash(struct stripe_head *sh)
 {
         PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector);
 
-        if (sh->hash_pprev) {
-                if (sh->hash_next)
-                        sh->hash_next->hash_pprev = sh->hash_pprev;
-                *sh->hash_pprev = sh->hash_next;
-                sh->hash_pprev = NULL;
-        }
+        hlist_del_init(&sh->hash);
 }
 
-static __inline__ void insert_hash(raid6_conf_t *conf, struct stripe_head *sh)
+static inline void insert_hash(raid6_conf_t *conf, struct stripe_head *sh)
 {
-        struct stripe_head **shp = &stripe_hash(conf, sh->sector);
+        struct hlist_head *hp = stripe_hash(conf, sh->sector);
 
         PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector);
 
         CHECK_DEVLOCK();
-        if ((sh->hash_next = *shp) != NULL)
-                (*shp)->hash_pprev = &sh->hash_next;
-        *shp = sh;
-        sh->hash_pprev = shp;
+        hlist_add_head(&sh->hash, hp);
 }
 
 
@@ -186,7 +176,7 @@ static void shrink_buffers(struct stripe_head *sh, int num)
                 if (!p)
                         continue;
                 sh->dev[i].page = NULL;
-                page_cache_release(p);
+                put_page(p);
         }
 }
 
@@ -247,10 +237,11 @@ static inline void init_stripe(struct stripe_head *sh, sector_t sector, int pd_i
 static struct stripe_head *__find_stripe(raid6_conf_t *conf, sector_t sector)
 {
         struct stripe_head *sh;
+        struct hlist_node *hn;
 
         CHECK_DEVLOCK();
         PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector);
-        for (sh = stripe_hash(conf, sector); sh; sh = sh->hash_next)
+        hlist_for_each_entry (sh, hn,  stripe_hash(conf, sector), hash)
                 if (sh->sector == sector)
                         return sh;
         PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector);
@@ -367,8 +358,8 @@ static void shrink_stripes(raid6_conf_t *conf)
         conf->slab_cache = NULL;
 }
 
-static int raid6_end_read_request (struct bio * bi, unsigned int bytes_done,
-                                   int error)
+static int raid6_end_read_request(struct bio * bi, unsigned int bytes_done,
+                                  int error)
 {
         struct stripe_head *sh = bi->bi_private;
         raid6_conf_t *conf = sh->raid_conf;
@@ -420,9 +411,35 @@ static int raid6_end_read_request (struct bio * bi, unsigned int bytes_done,
 #else
                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
 #endif
+                if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
+                        printk(KERN_INFO "raid6: read error corrected!!\n");
+                        clear_bit(R5_ReadError, &sh->dev[i].flags);
+                        clear_bit(R5_ReWrite, &sh->dev[i].flags);
+                }
+                if (atomic_read(&conf->disks[i].rdev->read_errors))
+                        atomic_set(&conf->disks[i].rdev->read_errors, 0);
         } else {
-                md_error(conf->mddev, conf->disks[i].rdev);
+                int retry = 0;
                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
+                atomic_inc(&conf->disks[i].rdev->read_errors);
+                if (conf->mddev->degraded)
+                        printk(KERN_WARNING "raid6: read error not correctable.\n");
+                else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
+                        /* Oh, no!!! */
+                        printk(KERN_WARNING "raid6: read error NOT corrected!!\n");
+                else if (atomic_read(&conf->disks[i].rdev->read_errors)
+                         > conf->max_nr_stripes)
+                        printk(KERN_WARNING
+                               "raid6: Too many read errors, failing device.\n");
+                else
+                        retry = 1;
+                if (retry)
+                        set_bit(R5_ReadError, &sh->dev[i].flags);
+                else {
+                        clear_bit(R5_ReadError, &sh->dev[i].flags);
+                        clear_bit(R5_ReWrite, &sh->dev[i].flags);
+                        md_error(conf->mddev, conf->disks[i].rdev);
+                }
         }
         rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
 #if 0
@@ -805,7 +822,7 @@ static void compute_parity(struct stripe_head *sh, int method)
 }
 
 /* Compute one missing block */
-static void compute_block_1(struct stripe_head *sh, int dd_idx)
+static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero)
 {
         raid6_conf_t *conf = sh->raid_conf;
         int i, count, disks = conf->raid_disks;
@@ -821,7 +838,7 @@ static void compute_block_1(struct stripe_head *sh, int dd_idx)
                 compute_parity(sh, UPDATE_PARITY);
         } else {
                 ptr[0] = page_address(sh->dev[dd_idx].page);
-                memset(ptr[0], 0, STRIPE_SIZE);
+                if (!nozero) memset(ptr[0], 0, STRIPE_SIZE);
                 count = 1;
                 for (i = disks ; i--; ) {
                         if (i == dd_idx || i == qd_idx)
@@ -838,7 +855,8 @@ static void compute_block_1(struct stripe_head *sh, int dd_idx)
                 }
                 if (count != 1)
                         xor_block(count, STRIPE_SIZE, ptr);
-                set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
+                if (!nozero) set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
+                else clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
         }
 }
 
@@ -871,7 +889,7 @@ static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
                         return;
                 } else {
                         /* We're missing D+Q; recompute D from P */
-                        compute_block_1(sh, (dd_idx1 == qd_idx) ? dd_idx2 : dd_idx1);
+                        compute_block_1(sh, (dd_idx1 == qd_idx) ? dd_idx2 : dd_idx1, 0);
                         compute_parity(sh, UPDATE_PARITY); /* Is this necessary? */
                         return;
                 }
@@ -982,6 +1000,12 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
 }
 
 
+static int page_is_zero(struct page *p)
+{
+        char *a = page_address(p);
+        return ((*(u32*)a) == 0 &&
+                memcmp(a, a+4, STRIPE_SIZE-4)==0);
+}
 /*
  * handle_stripe - do things to a stripe.
  *
@@ -1000,7 +1024,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
  *
  */
 
-static void handle_stripe(struct stripe_head *sh)
+static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
 {
         raid6_conf_t *conf = sh->raid_conf;
         int disks = conf->raid_disks;
@@ -1027,11 +1051,11 @@ static void handle_stripe(struct stripe_head *sh)
         syncing = test_bit(STRIPE_SYNCING, &sh->state);
         /* Now to look around and see what can be done */
 
+        rcu_read_lock();
         for (i=disks; i--; ) {
                 mdk_rdev_t *rdev;
                 dev = &sh->dev[i];
                 clear_bit(R5_Insync, &dev->flags);
-                clear_bit(R5_Syncio, &dev->flags);
 
                 PRINTK("check %d: state 0x%lx read %p write %p written %p\n",
                         i, dev->flags, dev->toread, dev->towrite, dev->written);
@@ -1070,14 +1094,21 @@ static void handle_stripe(struct stripe_head *sh)
                                 non_overwrite++;
                 }
                 if (dev->written) written++;
-                rdev = conf->disks[i].rdev; /* FIXME, should I be looking rdev */
+                rdev = rcu_dereference(conf->disks[i].rdev);
                 if (!rdev || !test_bit(In_sync, &rdev->flags)) {
+                        /* The ReadError flag will just be confusing now */
+                        clear_bit(R5_ReadError, &dev->flags);
+                        clear_bit(R5_ReWrite, &dev->flags);
+                }
+                if (!rdev || !test_bit(In_sync, &rdev->flags)
+                    || test_bit(R5_ReadError, &dev->flags)) {
                         if ( failed < 2 )
                                 failed_num[failed] = i;
                         failed++;
                 } else
                         set_bit(R5_Insync, &dev->flags);
         }
+        rcu_read_unlock();
         PRINTK("locked=%d uptodate=%d to_read=%d"
                " to_write=%d failed=%d failed_num=%d,%d\n",
                locked, uptodate, to_read, to_write, failed,
@@ -1088,6 +1119,17 @@ static void handle_stripe(struct stripe_head *sh)
         if (failed > 2 && to_read+to_write+written) {
                 for (i=disks; i--; ) {
                         int bitmap_end = 0;
+
+                        if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
+                                mdk_rdev_t *rdev;
+                                rcu_read_lock();
+                                rdev = rcu_dereference(conf->disks[i].rdev);
+                                if (rdev && test_bit(In_sync, &rdev->flags))
+                                        /* multiple read failures in one stripe */
+                                        md_error(conf->mddev, rdev);
+                                rcu_read_unlock();
+                        }
+
                         spin_lock_irq(&conf->device_lock);
                         /* fail all writes first */
                         bi = sh->dev[i].towrite;
@@ -1123,7 +1165,8 @@ static void handle_stripe(struct stripe_head *sh)
                         }
 
                         /* fail any reads if this device is non-operational */
-                        if (!test_bit(R5_Insync, &sh->dev[i].flags)) {
+                        if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
+                            test_bit(R5_ReadError, &sh->dev[i].flags)) {
                                 bi = sh->dev[i].toread;
                                 sh->dev[i].toread = NULL;
                                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
@@ -1228,7 +1271,7 @@ static void handle_stripe(struct stripe_head *sh)
                                 if (uptodate == disks-1) {
                                         PRINTK("Computing stripe %llu block %d\n",
                                                (unsigned long long)sh->sector, i);
-                                        compute_block_1(sh, i);
+                                        compute_block_1(sh, i, 0);
                                         uptodate++;
                                 } else if ( uptodate == disks-2 && failed >= 2 ) {
                                         /* Computing 2-failure is *very* expensive; only do it if failed >= 2 */
@@ -1259,9 +1302,6 @@ static void handle_stripe(struct stripe_head *sh)
                                         locked++;
                                         PRINTK("Reading block %d (sync=%d)\n",
                                                 i, syncing);
-                                        if (syncing)
-                                                md_sync_acct(conf->disks[i].rdev->bdev,
-                                                             STRIPE_SECTORS);
                                 }
                         }
                 }
@@ -1323,7 +1363,7 @@ static void handle_stripe(struct stripe_head *sh)
                                 /* We have failed blocks and need to compute them */
                                 switch ( failed ) {
                                 case 0: BUG();
-                                case 1: compute_block_1(sh, failed_num[0]); break;
+                                case 1: compute_block_1(sh, failed_num[0], 0); break;
                                 case 2: compute_block_2(sh, failed_num[0], failed_num[1]); break;
                                 default: BUG(); /* This request should have been failed? */
                                 }
@@ -1338,12 +1378,10 @@ static void handle_stripe(struct stripe_head *sh)
                                                (unsigned long long)sh->sector, i);
                                         locked++;
                                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
-#if 0 /**** FIX: I don't understand the logic here... ****/
-                                        if (!test_bit(R5_Insync, &sh->dev[i].flags)
-                                            || ((i==pd_idx || i==qd_idx) && failed == 0)) /* FIX? */
-                                                set_bit(STRIPE_INSYNC, &sh->state);
-#endif
                                 }
+                        /* after a RECONSTRUCT_WRITE, the stripe MUST be in-sync */
+                        set_bit(STRIPE_INSYNC, &sh->state);
+
                         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
                                 atomic_dec(&conf->preread_active_stripes);
                                 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
@@ -1356,84 +1394,119 @@ static void handle_stripe(struct stripe_head *sh)
          * Any reads will already have been scheduled, so we just see if enough data
          * is available
          */
-        if (syncing && locked == 0 &&
-            !test_bit(STRIPE_INSYNC, &sh->state) && failed <= 2) {
-                set_bit(STRIPE_HANDLE, &sh->state);
-#if 0 /* RAID-6: Don't support CHECK PARITY yet */
-                if (failed == 0) {
-                        char *pagea;
-                        if (uptodate != disks)
-                                BUG();
-                        compute_parity(sh, CHECK_PARITY);
-                        uptodate--;
-                        pagea = page_address(sh->dev[pd_idx].page);
-                        if ((*(u32*)pagea) == 0 &&
-                            !memcmp(pagea, pagea+4, STRIPE_SIZE-4)) {
-                                /* parity is correct (on disc, not in buffer any more) */
-                                set_bit(STRIPE_INSYNC, &sh->state);
-                        }
-                }
-#endif
-                if (!test_bit(STRIPE_INSYNC, &sh->state)) {
-                        int failed_needupdate[2];
-                        struct r5dev *adev, *bdev;
-
-                        if ( failed < 1 )
-                                failed_num[0] = pd_idx;
-                        if ( failed < 2 )
-                                failed_num[1] = (failed_num[0] == qd_idx) ? pd_idx : qd_idx;
+        if (syncing && locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state)) {
+                int update_p = 0, update_q = 0;
+                struct r5dev *dev;
 
-                        failed_needupdate[0] = !test_bit(R5_UPTODATE, &sh->dev[failed_num[0]].flags);
-                        failed_needupdate[1] = !test_bit(R5_UPTODATE, &sh->dev[failed_num[1]].flags);
+                set_bit(STRIPE_HANDLE, &sh->state);
 
-                        PRINTK("sync: failed=%d num=%d,%d fnu=%u%u\n",
-                               failed, failed_num[0], failed_num[1], failed_needupdate[0], failed_needupdate[1]);
+                BUG_ON(failed>2);
+                BUG_ON(uptodate < disks);
+                /* Want to check and possibly repair P and Q.
+                 * However there could be one 'failed' device, in which
+                 * case we can only check one of them, possibly using the
+                 * other to generate missing data
+                 */
 
-#if 0  /* RAID-6: This code seems to require that CHECK_PARITY destroys the uptodateness of the parity */
-                        /* should be able to compute the missing block(s) and write to spare */
-                        if ( failed_needupdate[0] ^ failed_needupdate[1] ) {
-                                if (uptodate+1 != disks)
-                                        BUG();
-                                compute_block_1(sh, failed_needupdate[0] ? failed_num[0] : failed_num[1]);
-                                uptodate++;
-                        } else if ( failed_needupdate[0] & failed_needupdate[1] ) {
-                                if (uptodate+2 != disks)
-                                        BUG();
-                                compute_block_2(sh, failed_num[0], failed_num[1]);
-                                uptodate += 2;
+                /* If !tmp_page, we cannot do the calculations,
+                 * but as we have set STRIPE_HANDLE, we will soon be called
+                 * by stripe_handle with a tmp_page - just wait until then.
+                 */
+                if (tmp_page) {
+                        if (failed == q_failed) {
+                                /* The only possible failed device holds 'Q', so it makes
+                                 * sense to check P (If anything else were failed, we would
+                                 * have used P to recreate it).
+                                 */
+                                compute_block_1(sh, pd_idx, 1);
+                                if (!page_is_zero(sh->dev[pd_idx].page)) {
+                                        compute_block_1(sh,pd_idx,0);
+                                        update_p = 1;
+                                }
+                        }
+                        if (!q_failed && failed < 2) {
+                                /* q is not failed, and we didn't use it to generate
+                                 * anything, so it makes sense to check it
+                                 */
+                                memcpy(page_address(tmp_page),
+                                       page_address(sh->dev[qd_idx].page),
+                                       STRIPE_SIZE);
+                                compute_parity(sh, UPDATE_PARITY);
+                                if (memcmp(page_address(tmp_page),
+                                           page_address(sh->dev[qd_idx].page),
+                                           STRIPE_SIZE)!= 0) {
+                                        clear_bit(STRIPE_INSYNC, &sh->state);
+                                        update_q = 1;
+                                }
+                        }
+                        if (update_p || update_q) {
+                                conf->mddev->resync_mismatches += STRIPE_SECTORS;
+                                if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
+                                        /* don't try to repair!! */
+                                        update_p = update_q = 0;
                         }
-#else
-                        compute_block_2(sh, failed_num[0], failed_num[1]);
-                        uptodate += failed_needupdate[0] + failed_needupdate[1];
-#endif
 
-                        if (uptodate != disks)
-                                BUG();
+                        /* now write out any block on a failed drive,
+                         * or P or Q if they need it
+                         */
 
-                        PRINTK("Marking for sync stripe %llu blocks %d,%d\n",
-                               (unsigned long long)sh->sector, failed_num[0], failed_num[1]);
+                        if (failed == 2) {
+                                dev = &sh->dev[failed_num[1]];
+                                locked++;
+                                set_bit(R5_LOCKED, &dev->flags);
+                                set_bit(R5_Wantwrite, &dev->flags);
+                        }
+                        if (failed >= 1) {
+                                dev = &sh->dev[failed_num[0]];
+                                locked++;
+                                set_bit(R5_LOCKED, &dev->flags);
+                                set_bit(R5_Wantwrite, &dev->flags);
+                        }
 
-                        /**** FIX: Should we really do both of these unconditionally? ****/
-                        adev = &sh->dev[failed_num[0]];
-                        locked += !test_bit(R5_LOCKED, &adev->flags);
-                        set_bit(R5_LOCKED, &adev->flags);
-                        set_bit(R5_Wantwrite, &adev->flags);
-                        bdev = &sh->dev[failed_num[1]];
-                        locked += !test_bit(R5_LOCKED, &bdev->flags);
-                        set_bit(R5_LOCKED, &bdev->flags);
+                        if (update_p) {
+                                dev = &sh->dev[pd_idx];
+                                locked ++;
+                                set_bit(R5_LOCKED, &dev->flags);
+                                set_bit(R5_Wantwrite, &dev->flags);
+                        }
+                        if (update_q) {
+                                dev = &sh->dev[qd_idx];
+                                locked++;
+                                set_bit(R5_LOCKED, &dev->flags);
+                                set_bit(R5_Wantwrite, &dev->flags);
+                        }
                         clear_bit(STRIPE_DEGRADED, &sh->state);
-                        set_bit(R5_Wantwrite, &bdev->flags);
 
                         set_bit(STRIPE_INSYNC, &sh->state);
-                        set_bit(R5_Syncio, &adev->flags);
-                        set_bit(R5_Syncio, &bdev->flags);
                 }
         }
+
         if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
                 md_done_sync(conf->mddev, STRIPE_SECTORS,1);
                 clear_bit(STRIPE_SYNCING, &sh->state);
         }
 
+        /* If the failed drives are just a ReadError, then we might need
+         * to progress the repair/check process
+         */
+        if (failed <= 2 && ! conf->mddev->ro)
+                for (i=0; i<failed;i++) {
+                        dev = &sh->dev[failed_num[i]];
+                        if (test_bit(R5_ReadError, &dev->flags)
+                            && !test_bit(R5_LOCKED, &dev->flags)
+                            && test_bit(R5_UPTODATE, &dev->flags)
+                                ) {
+                                if (!test_bit(R5_ReWrite, &dev->flags)) {
+                                        set_bit(R5_Wantwrite, &dev->flags);
+                                        set_bit(R5_ReWrite, &dev->flags);
+                                        set_bit(R5_LOCKED, &dev->flags);
+                                } else {
+                                        /* let's read it back */
+                                        set_bit(R5_Wantread, &dev->flags);
+                                        set_bit(R5_LOCKED, &dev->flags);
+                                }
+                        }
+                }
         spin_unlock(&sh->lock);
 
         while ((bi=return_bi)) {
@@ -1472,7 +1545,7 @@ static void handle_stripe(struct stripe_head *sh)
                 rcu_read_unlock();
 
                 if (rdev) {
-                        if (test_bit(R5_Syncio, &sh->dev[i].flags))
+                        if (syncing)
                                 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
 
                         bi->bi_bdev = rdev->bdev;
@@ -1489,6 +1562,9 @@ static void handle_stripe(struct stripe_head *sh)
                         bi->bi_io_vec[0].bv_offset = 0;
                         bi->bi_size = STRIPE_SIZE;
                         bi->bi_next = NULL;
+                        if (rw == WRITE &&
+                            test_bit(R5_ReWrite, &sh->dev[i].flags))
+                                atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
                         generic_make_request(bi);
                 } else {
                         if (rw == 1)
@@ -1664,7 +1740,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
                         }
                         finish_wait(&conf->wait_for_overlap, &w);
                         raid6_plug_device(conf);
-                        handle_stripe(sh);
+                        handle_stripe(sh, NULL);
                         release_stripe(sh);
                 } else {
                         /* cannot get stripe for read-ahead, just give-up */
@@ -1728,6 +1804,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
                 return rv;
         }
         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
+            !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
             !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
                 /* we can skip this block, and probably more */
                 sync_blocks /= STRIPE_SECTORS;
@@ -1765,7 +1842,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
         clear_bit(STRIPE_INSYNC, &sh->state);
         spin_unlock(&sh->lock);
 
-        handle_stripe(sh);
+        handle_stripe(sh, NULL);
         release_stripe(sh);
 
         return STRIPE_SECTORS;
@@ -1821,7 +1898,7 @@ static void raid6d (mddev_t *mddev)
                 spin_unlock_irq(&conf->device_lock);
 
                 handled++;
-                handle_stripe(sh);
+                handle_stripe(sh, conf->spare_page);
                 release_stripe(sh);
 
                 spin_lock_irq(&conf->device_lock);
@@ -1848,17 +1925,19 @@ static int run(mddev_t *mddev)
                 return -EIO;
         }
 
-        mddev->private = kmalloc (sizeof (raid6_conf_t)
-                                  + mddev->raid_disks * sizeof(struct disk_info),
-                                  GFP_KERNEL);
+        mddev->private = kzalloc(sizeof (raid6_conf_t)
+                                 + mddev->raid_disks * sizeof(struct disk_info),
+                                 GFP_KERNEL);
         if ((conf = mddev->private) == NULL)
                 goto abort;
-        memset (conf, 0, sizeof (*conf) + mddev->raid_disks * sizeof(struct disk_info) );
         conf->mddev = mddev;
 
-        if ((conf->stripe_hashtbl = (struct stripe_head **) __get_free_pages(GFP_ATOMIC, HASH_PAGES_ORDER)) == NULL)
+        if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
+                goto abort;
+
+        conf->spare_page = alloc_page(GFP_KERNEL);
+        if (!conf->spare_page)
                 goto abort;
-        memset(conf->stripe_hashtbl, 0, HASH_PAGES * PAGE_SIZE);
 
         spin_lock_init(&conf->device_lock);
         init_waitqueue_head(&conf->wait_for_stripe);
@@ -1929,13 +2008,18 @@ static int run(mddev_t *mddev)
                 goto abort;
         }
 
-#if 0                           /* FIX: For now */
         if (mddev->degraded > 0 &&
             mddev->recovery_cp != MaxSector) {
-                printk(KERN_ERR "raid6: cannot start dirty degraded array for %s\n", mdname(mddev));
-                goto abort;
+                if (mddev->ok_start_degraded)
+                        printk(KERN_WARNING "raid6: starting dirty degraded array:%s"
+                               "- data corruption possible.\n",
+                               mdname(mddev));
+                else {
+                        printk(KERN_ERR "raid6: cannot start dirty degraded array"
+                               " for %s\n", mdname(mddev));
+                        goto abort;
+                }
         }
-#endif
 
         {
                 mddev->thread = md_register_thread(raid6d, mddev, "%s_raid6");
@@ -1977,7 +2061,7 @@ static int run(mddev_t *mddev)
          */
         {
                 int stripe = (mddev->raid_disks-2) * mddev->chunk_size
-                        / PAGE_CACHE_SIZE;
+                        / PAGE_SIZE;
                 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
                         mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
         }
@@ -1985,18 +2069,14 @@ static int run(mddev_t *mddev)
         /* Ok, everything is just fine now */
         mddev->array_size =  mddev->size * (mddev->raid_disks - 2);
 
-        if (mddev->bitmap)
-                mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
-
         mddev->queue->unplug_fn = raid6_unplug_device;
         mddev->queue->issue_flush_fn = raid6_issue_flush;
         return 0;
 abort:
         if (conf) {
                 print_raid6_conf(conf);
-                if (conf->stripe_hashtbl)
-                        free_pages((unsigned long) conf->stripe_hashtbl,
-                                                        HASH_PAGES_ORDER);
+                safe_put_page(conf->spare_page);
+                kfree(conf->stripe_hashtbl);
                 kfree(conf);
         }
         mddev->private = NULL;
@@ -2013,7 +2093,7 @@ static int stop (mddev_t *mddev)
         md_unregister_thread(mddev->thread);
         mddev->thread = NULL;
         shrink_stripes(conf);
-        free_pages((unsigned long) conf->stripe_hashtbl, HASH_PAGES_ORDER);
+        kfree(conf->stripe_hashtbl);
         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
         kfree(conf);
         mddev->private = NULL;
@@ -2040,12 +2120,13 @@ static void print_sh (struct seq_file *seq, struct stripe_head *sh)
 static void printall (struct seq_file *seq, raid6_conf_t *conf)
 {
         struct stripe_head *sh;
+        struct hlist_node *hn;
         int i;
 
         spin_lock_irq(&conf->device_lock);
         for (i = 0; i < NR_HASH; i++) {
                 sh = conf->stripe_hashtbl[i];
-                for (; sh; sh = sh->hash_next) {
+                hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
                         if (sh->raid_conf != conf)
                                 continue;
                         print_sh(seq, sh);
@@ -2223,17 +2304,12 @@ static void raid6_quiesce(mddev_t *mddev, int state)
                 spin_unlock_irq(&conf->device_lock);
                 break;
         }
-        if (mddev->thread) {
-                if (mddev->bitmap)
-                        mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
-                else
-                        mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
-                md_wakeup_thread(mddev->thread);
-        }
 }
-static mdk_personality_t raid6_personality=
+
+static struct mdk_personality raid6_personality =
 {
         .name           = "raid6",
+        .level          = 6,
         .owner          = THIS_MODULE,
         .make_request   = make_request,
         .run            = run,
@@ -2248,7 +2324,7 @@ static mdk_personality_t raid6_personality=
         .quiesce        = raid6_quiesce,
 };
 
-static int __init raid6_init (void)
+static int __init raid6_init(void)
 {
         int e;
 
@@ -2256,15 +2332,17 @@ static int __init raid6_init (void)
         if ( e )
                 return e;
 
-        return register_md_personality (RAID6, &raid6_personality);
+        return register_md_personality(&raid6_personality);
 }
 
 static void raid6_exit (void)
 {
-        unregister_md_personality (RAID6);
+        unregister_md_personality(&raid6_personality);
 }
 
 module_init(raid6_init);
 module_exit(raid6_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-8"); /* RAID6 */
+MODULE_ALIAS("md-raid6");
+MODULE_ALIAS("md-level-6");