1 files changed, 3 insertions, 2 deletions

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index 9818d4a3f829..2c66ddbbe670 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -429,11 +429,12 @@ int btrfs_save_ino_cache(struct btrfs_root *root,
         num_bytes = trans->bytes_reserved;
         /*
          * 1 item for inode item insertion if need
-         * 3 items for inode item update (in the worst case)
+         * 4 items for inode item update (in the worst case)
+         * 1 items for slack space if we need do truncation
          * 1 item for free space object
          * 3 items for pre-allocation
          */
-        trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 8);
+        trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 10);
         ret = btrfs_block_rsv_add(root, trans->block_rsv,
                                   trans->bytes_reserved,
                                   BTRFS_RESERVE_NO_FLUSH);