> - error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp); > + resblks = XFS_IS_REALTIME_INODE(ip) ? XFS_DIOSTRAT_SPACE_RES(mp, 0) : 0; This probably wants a comment explaining that we need the block reservation for bmap btree block allocations / splits that can happen because we can split a written extent into one written and one unwritten, while for the data fork we'll always just shorten or remove extents. I'd also find this more readable if resblks was initialized to 0, and this became a: if (XFS_IS_REALTIME_INODE(ip)) resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
