Btrfs: Add checks for last byte in disk to allocator grouping

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a340eeedd6c7..9e0869959cde 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1611,8 +1611,13 @@ check_pending:
         }
         ins->offset = num_bytes;
         btrfs_free_path(path);
-        if (last_ptr)
+        if (last_ptr) {
                 *last_ptr = ins->objectid + ins->offset;
+                if (*last_ptr ==
+                    btrfs_super_total_bytes(&root->fs_info->super_copy)) {
+                        *last_ptr = 0;
+                }
+        }
         return 0;
 
 new_group: