dm raid: consume sizes after md_finish_reshape() completes changing them

The md raid personalities call md_finish_reshape() at the end of a
reshape conversion which adjusts rdev->sectors.

Correct/check rdev->sectors before initiating a reshape and raise the
recovery pointer accordingly.

Otherwise, the DM raid coordinated reshape will fail.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 398314b..c3ea433 100644 (file)
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -2640,12 +2640,19 @@ static int rs_adjust_data_offsets(struct raid_set *rs)
         * Make sure we got a minimum amount of free sectors per device
         */
        if (rs->data_offset &&
-           to_sector(i_size_read(rdev->bdev->bd_inode)) - rdev->sectors < MIN_FREE_RESHAPE_SPACE) {
+           to_sector(i_size_read(rdev->bdev->bd_inode)) - rs->md.dev_sectors < MIN_FREE_RESHAPE_SPACE) {
                rs->ti->error = data_offset ? "No space for forward reshape" :
                                              "No space for backward reshape";
                return -ENOSPC;
        }
 out:
+       /*
+        * Raise recovery_cp in case data_offset != 0 to
+        * avoid false recovery positives in the constructor.
+        */
+       if (rs->md.recovery_cp < rs->md.dev_sectors)
+               rs->md.recovery_cp += rs->dev[0].rdev.data_offset;
+
        /* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
        rdev_for_each(rdev, &rs->md) {
                if (!test_bit(Journal, &rdev->flags)) {
@@ -2777,6 +2784,23 @@ static int rs_prepare_reshape(struct raid_set *rs)
        return 0;
 }
 
+/* Get reshape sectors from data_offsets or raid set */
+static sector_t _get_reshape_sectors(struct raid_set *rs)
+{
+       struct md_rdev *rdev;
+       sector_t reshape_sectors = 0;
+
+       rdev_for_each(rdev, &rs->md)
+               if (!test_bit(Journal, &rdev->flags)) {
+                       reshape_sectors = (rdev->data_offset > rdev->new_data_offset) ?
+                                       rdev->data_offset - rdev->new_data_offset :
+                                       rdev->new_data_offset - rdev->data_offset;
+                       break;
+               }
+
+       return max(reshape_sectors, (sector_t) rs->data_offset);
+}
+
 /*
  *
  * - change raid layout
@@ -2788,6 +2812,7 @@ static int rs_setup_reshape(struct raid_set *rs)
 {
        int r = 0;
        unsigned int cur_raid_devs, d;
+       sector_t reshape_sectors = _get_reshape_sectors(rs);
        struct mddev *mddev = &rs->md;
        struct md_rdev *rdev;
 
@@ -2804,13 +2829,13 @@ static int rs_setup_reshape(struct raid_set *rs)
        /*
         * Adjust array size:
         *
-        * - in case of adding disks, array size has
+        * - in case of adding disk(s), array size has
         *   to grow after the disk adding reshape,
         *   which'll hapen in the event handler;
         *   reshape will happen forward, so space has to
         *   be available at the beginning of each disk
         *
-        * - in case of removing disks, array size
+        * - in case of removing disk(s), array size
         *   has to shrink before starting the reshape,
         *   which'll happen here;
         *   reshape will happen backward, so space has to
@@ -2841,7 +2866,7 @@ static int rs_setup_reshape(struct raid_set *rs)
                        rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
                }
 
-               mddev->reshape_backwards = 0; /* adding disks -> forward reshape */
+               mddev->reshape_backwards = 0; /* adding disk(s) -> forward reshape */
 
        /* Remove disk(s) */
        } else if (rs->delta_disks < 0) {
@@ -2874,6 +2899,15 @@ static int rs_setup_reshape(struct raid_set *rs)
                mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
        }
 
+       /*
+        * Adjust device size for forward reshape
+        * because md_finish_reshape() reduces it.
+        */
+       if (!mddev->reshape_backwards)
+               rdev_for_each(rdev, &rs->md)
+                       if (!test_bit(Journal, &rdev->flags))
+                               rdev->sectors += reshape_sectors;
+
        return r;
 }