1 files changed, 120 insertions, 20 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index b29135acb1d9..20ae32d67e21 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -22,6 +22,7 @@
 #include <linux/raid/raid5.h>
 #include <linux/highmem.h>
 #include <linux/bitops.h>
+#include <linux/kthread.h>
 #include <asm/atomic.h>
 
 #include <linux/raid/bitmap.h>
@@ -1504,6 +1505,7 @@ static void handle_stripe(struct stripe_head *sh)
                 clear_bit(STRIPE_EXPANDING, &sh->state);
         } else if (expanded) {
                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
+                atomic_dec(&conf->reshape_stripes);
                 wake_up(&conf->wait_for_overlap);
                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
         }
@@ -1875,6 +1877,26 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
                  */
                 int i;
                 int dd_idx;
+
+                if (sector_nr == 0 &&
+                    conf->expand_progress != 0) {
+                        /* restarting in the middle, skip the initial sectors */
+                        sector_nr = conf->expand_progress;
+                        sector_div(sector_nr, conf->raid_disks-1);
+                        *skipped = 1;
+                        return sector_nr;
+                }
+
+                /* Cannot proceed until we've updated the superblock... */
+                wait_event(conf->wait_for_overlap,
+                           atomic_read(&conf->reshape_stripes)==0);
+                mddev->reshape_position = conf->expand_progress;
+
+                mddev->sb_dirty = 1;
+                md_wakeup_thread(mddev->thread);
+                wait_event(mddev->sb_wait, mddev->sb_dirty == 0 ||
+                        kthread_should_stop());
+
                 for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) {
                         int j;
                         int skipped = 0;
@@ -1882,6 +1904,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
                         sh = get_active_stripe(conf, sector_nr+i,
                                                conf->raid_disks, pd_idx, 0);
                         set_bit(STRIPE_EXPANDING, &sh->state);
+                        atomic_inc(&conf->reshape_stripes);
                         /* If any of this stripe is beyond the end of the old
                          * array, then we need to zero those blocks
                          */
@@ -2121,10 +2144,61 @@ static int run(mddev_t *mddev)
                 return -EIO;
         }
 
+        if (mddev->reshape_position != MaxSector) {
+                /* Check that we can continue the reshape.
+                 * Currently only disks can change, it must
+                 * increase, and we must be past the point where
+                 * a stripe over-writes itself
+                 */
+                sector_t here_new, here_old;
+                int old_disks;
+
+                if (mddev->new_level != mddev->level ||
+                    mddev->new_layout != mddev->layout ||
+                    mddev->new_chunk != mddev->chunk_size) {
+                        printk(KERN_ERR "raid5: %s: unsupported reshape required - aborting.\n",
+                               mdname(mddev));
+                        return -EINVAL;
+                }
+                if (mddev->delta_disks <= 0) {
+                        printk(KERN_ERR "raid5: %s: unsupported reshape (reduce disks) required - aborting.\n",
+                               mdname(mddev));
+                        return -EINVAL;
+                }
+                old_disks = mddev->raid_disks - mddev->delta_disks;
+                /* reshape_position must be on a new-stripe boundary, and one
+                 * further up in new geometry must map after here in old geometry.
+                 */
+                here_new = mddev->reshape_position;
+                if (sector_div(here_new, (mddev->chunk_size>>9)*(mddev->raid_disks-1))) {
+                        printk(KERN_ERR "raid5: reshape_position not on a stripe boundary\n");
+                        return -EINVAL;
+                }
+                /* here_new is the stripe we will write to */
+                here_old = mddev->reshape_position;
+                sector_div(here_old, (mddev->chunk_size>>9)*(old_disks-1));
+                /* here_old is the first stripe that we might need to read from */
+                if (here_new >= here_old) {
+                        /* Reading from the same stripe as writing to - bad */
+                        printk(KERN_ERR "raid5: reshape_position too early for auto-recovery - aborting.\n");
+                        return -EINVAL;
+                }
+                printk(KERN_INFO "raid5: reshape will continue\n");
+                /* OK, we should be able to continue; */
+        }
+
+
         mddev->private = kzalloc(sizeof (raid5_conf_t), GFP_KERNEL);
         if ((conf = mddev->private) == NULL)
                 goto abort;
-        conf->disks = kzalloc(mddev->raid_disks * sizeof(struct disk_info),
+        if (mddev->reshape_position == MaxSector) {
+                conf->previous_raid_disks = conf->raid_disks = mddev->raid_disks;
+        } else {
+                conf->raid_disks = mddev->raid_disks;
+                conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
+        }
+
+        conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info),
                               GFP_KERNEL);
         if (!conf->disks)
                 goto abort;
@@ -2148,7 +2222,7 @@ static int run(mddev_t *mddev)
 
         ITERATE_RDEV(mddev,rdev,tmp) {
                 raid_disk = rdev->raid_disk;
-                if (raid_disk >= mddev->raid_disks
+                if (raid_disk >= conf->raid_disks
                     || raid_disk < 0)
                         continue;
                 disk = conf->disks + raid_disk;
@@ -2164,7 +2238,6 @@ static int run(mddev_t *mddev)
                 }
         }
 
-        conf->raid_disks = mddev->raid_disks;
         /*
          * 0 for a fully functional array, 1 for a degraded array.
          */
@@ -2174,7 +2247,7 @@ static int run(mddev_t *mddev)
         conf->level = mddev->level;
         conf->algorithm = mddev->layout;
         conf->max_nr_stripes = NR_STRIPES;
-        conf->expand_progress = MaxSector;
+        conf->expand_progress = mddev->reshape_position;
 
         /* device size must be a multiple of chunk size */
         mddev->size &= ~(mddev->chunk_size/1024 -1);
@@ -2247,6 +2320,20 @@ static int run(mddev_t *mddev)
 
         print_raid5_conf(conf);
 
+        if (conf->expand_progress != MaxSector) {
+                printk("...ok start reshape thread\n");
+                atomic_set(&conf->reshape_stripes, 0);
+                clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+                clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
+                set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
+                set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+                mddev->sync_thread = md_register_thread(md_do_sync, mddev,
+                                                        "%s_reshape");
+                /* FIXME if md_register_thread fails?? */
+                md_wakeup_thread(mddev->sync_thread);
+
+        }
+
         /* read-ahead size must cover two whole stripes, which is
          * 2 * (n-1) * chunksize where 'n' is the number of raid devices
          */
@@ -2262,8 +2349,8 @@ static int run(mddev_t *mddev)
 
         mddev->queue->unplug_fn = raid5_unplug_device;
         mddev->queue->issue_flush_fn = raid5_issue_flush;
+        mddev->array_size =  mddev->size * (conf->previous_raid_disks - 1);
 
-        mddev->array_size =  mddev->size * (mddev->raid_disks - 1);
         return 0;
 abort:
         if (conf) {
@@ -2436,7 +2523,7 @@ static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
         /*
          * find the disk ...
          */
-        for (disk=0; disk < mddev->raid_disks; disk++)
+        for (disk=0; disk < conf->raid_disks; disk++)
                 if ((p=conf->disks + disk)->rdev == NULL) {
                         clear_bit(In_sync, &rdev->flags);
                         rdev->raid_disk = disk;
@@ -2518,9 +2605,10 @@ static int raid5_reshape(mddev_t *mddev, int raid_disks)
         if (err)
                 return err;
 
+        atomic_set(&conf->reshape_stripes, 0);
         spin_lock_irq(&conf->device_lock);
         conf->previous_raid_disks = conf->raid_disks;
-        mddev->raid_disks = conf->raid_disks = raid_disks;
+        conf->raid_disks = raid_disks;
         conf->expand_progress = 0;
         spin_unlock_irq(&conf->device_lock);
 
@@ -2542,6 +2630,14 @@ static int raid5_reshape(mddev_t *mddev, int raid_disks)
                 }
 
         mddev->degraded = (raid_disks - conf->previous_raid_disks) - added_devices;
+        mddev->new_chunk = mddev->chunk_size;
+        mddev->new_layout = mddev->layout;
+        mddev->new_level = mddev->level;
+        mddev->raid_disks = raid_disks;
+        mddev->delta_disks = raid_disks - conf->previous_raid_disks;
+        mddev->reshape_position = 0;
+        mddev->sb_dirty = 1;
+
         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
@@ -2552,6 +2648,7 @@ static int raid5_reshape(mddev_t *mddev, int raid_disks)
                 mddev->recovery = 0;
                 spin_lock_irq(&conf->device_lock);
                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
+                mddev->delta_disks = 0;
                 conf->expand_progress = MaxSector;
                 spin_unlock_irq(&conf->device_lock);
                 return -EAGAIN;
@@ -2566,20 +2663,23 @@ static void end_reshape(raid5_conf_t *conf)
 {
         struct block_device *bdev;
 
-        conf->mddev->array_size = conf->mddev->size * (conf->mddev->raid_disks-1);
-        set_capacity(conf->mddev->gendisk, conf->mddev->array_size << 1);
-        conf->mddev->changed = 1;
-
-        bdev = bdget_disk(conf->mddev->gendisk, 0);
-        if (bdev) {
-                mutex_lock(&bdev->bd_inode->i_mutex);
-                i_size_write(bdev->bd_inode, conf->mddev->array_size << 10);
-                mutex_unlock(&bdev->bd_inode->i_mutex);
-                bdput(bdev);
+        if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
+                conf->mddev->array_size = conf->mddev->size * (conf->raid_disks-1);
+                set_capacity(conf->mddev->gendisk, conf->mddev->array_size << 1);
+                conf->mddev->changed = 1;
+
+                bdev = bdget_disk(conf->mddev->gendisk, 0);
+                if (bdev) {
+                        mutex_lock(&bdev->bd_inode->i_mutex);
+                        i_size_write(bdev->bd_inode, conf->mddev->array_size << 10);
+                        mutex_unlock(&bdev->bd_inode->i_mutex);
+                        bdput(bdev);
+                }
+                spin_lock_irq(&conf->device_lock);
+                conf->expand_progress = MaxSector;
+                spin_unlock_irq(&conf->device_lock);
+                conf->mddev->reshape_position = MaxSector;
         }
-        spin_lock_irq(&conf->device_lock);
-        conf->expand_progress = MaxSector;
-        spin_unlock_irq(&conf->device_lock);
 }
 
 static void raid5_quiesce(mddev_t *mddev, int state)