md: add 'size' as a personality method

In preparation for giving userspace control over ->array_sectors we need
to be able to retrieve the 'default' size, and the 'anticipated' size
when a reshape is requested.  For personalities that do not reshape emit
a warning if anything but the default size is requested.

In the raid5 case we need to update ->previous_raid_disks to make the
new 'default' size available.

Reviewed-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 11 insertions, 2 deletions

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 7eaca3209364..a2a83b0d5a95 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1922,6 +1922,14 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
         return nr_sectors;
 }
 
+static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
+{
+        if (sectors)
+                return sectors;
+
+        return mddev->dev_sectors;
+}
+
 static int run(mddev_t *mddev)
 {
         conf_t *conf;
@@ -2051,7 +2059,7 @@ static int run(mddev_t *mddev)
         /*
          * Ok, everything is just fine now
          */
-        mddev->array_sectors = mddev->dev_sectors;
+        mddev->array_sectors = raid1_size(mddev, 0, 0);
 
         mddev->queue->unplug_fn = raid1_unplug;
         mddev->queue->backing_dev_info.congested_fn = raid1_congested;
@@ -2116,7 +2124,7 @@ 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_sectors = sectors;
+        mddev->array_sectors = raid1_size(mddev, sectors, 0);
         set_capacity(mddev->gendisk, mddev->array_sectors);
         mddev->changed = 1;
         if (mddev->array_sectors > mddev->dev_sectors &&
@@ -2270,6 +2278,7 @@ static struct mdk_personality raid1_personality =
         .spare_active   = raid1_spare_active,
         .sync_request   = sync_request,
         .resize         = raid1_resize,
+        .size           = raid1_size,
         .check_reshape  = raid1_reshape,
         .quiesce        = raid1_quiesce,
 };