[PATCH v2 04/14] btrfs: fix front delete range calculation for RAID stripe extents

[Johannes Thumshirn <jth@kernel.org>]

From: Johannes Thumshirn <johannes.thumshirn@wdc.com>

When deleting the front of a RAID stripe-extent the delete code
miscalculates the size on how much to pad the remaining extent part in the
front.

Fix the calculation so we're always having the sizes we expect.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/raid-stripe-tree.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/raid-stripe-tree.c b/fs/btrfs/raid-stripe-tree.c
index 0c4d218a99d4aaea5da6c39624e20e77758a89d3..7fc6ef214f87d480df27023816dd800610d7dcf0 100644
--- a/fs/btrfs/raid-stripe-tree.c
+++ b/fs/btrfs/raid-stripe-tree.c
@@ -140,10 +140,12 @@ int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start, u64 le
 		 * length to the new size and then re-insert the item.
 		 */
 		if (found_end > end) {
-			u64 diff = found_end - end;
+			u64 diff_end = found_end - end;
 
 			btrfs_partially_delete_raid_extent(trans, path, &key,
-							   diff, diff);
+							   key.offset - length,
+							   length);
+			ASSERT(key.offset - diff_end == length);
 			break;
 		}
 

-- 
2.43.0