1 files changed, 38 insertions, 0 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index e4a66ab6b0fb..3540316886f2 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -3436,6 +3436,43 @@ static void raid10_quiesce(struct mddev *mddev, int state)
         }
 }
 
+static int raid10_resize(struct mddev *mddev, sector_t sectors)
+{
+        /* Resize of 'far' arrays is not supported.
+         * For 'near' and 'offset' arrays we can set the
+         * number of sectors used to be an appropriate multiple
+         * of the chunk size.
+         * For 'offset', this is far_copies*chunksize.
+         * For 'near' the multiplier is the LCM of
+         * near_copies and raid_disks.
+         * So if far_copies > 1 && !far_offset, fail.
+         * Else find LCM(raid_disks, near_copy)*far_copies and
+         * multiply by chunk_size.  Then round to this number.
+         * This is mostly done by raid10_size()
+         */
+        struct r10conf *conf = mddev->private;
+        sector_t oldsize, size;
+
+        if (conf->far_copies > 1 && !conf->far_offset)
+                return -EINVAL;
+
+        oldsize = raid10_size(mddev, 0, 0);
+        size = raid10_size(mddev, sectors, 0);
+        md_set_array_sectors(mddev, size);
+        if (mddev->array_sectors > size)
+                return -EINVAL;
+        set_capacity(mddev->gendisk, mddev->array_sectors);
+        revalidate_disk(mddev->gendisk);
+        if (sectors > mddev->dev_sectors &&
+            mddev->recovery_cp > oldsize) {
+                mddev->recovery_cp = oldsize;
+                set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+        }
+        mddev->dev_sectors = sectors;
+        mddev->resync_max_sectors = size;
+        return 0;
+}
+
 static void *raid10_takeover_raid0(struct mddev *mddev)
 {
         struct md_rdev *rdev;
@@ -3505,6 +3542,7 @@ static struct md_personality raid10_personality =
         .sync_request   = sync_request,
         .quiesce        = raid10_quiesce,
         .size           = raid10_size,
+        .resize         = raid10_resize,
         .takeover       = raid10_takeover,
 };