- size += n;
- size += sizeof(xfs_dir2_data_off_t);
- if (ftype)
- size += sizeof(__uint8_t);
- return roundup(size, XFS_DIR2_DATA_ALIGN);
-}
+/*
+ * For special situations, the dirent size ends up fixed because we always know
+ * what the size of the entry is. That's true for the "." and "..", and
+ * therefore we know that they are a fixed size and hence their offsets are
+ * constant, as is the first entry.
+ *
+ * Hence, this calculation is written as a macro to be able to be calculated at
+ * compile time and so certain offsets can be calculated directly in the
+ * structure initaliser via the macro. There are two macros - one for dirents
+ * with ftype and without so there are no unresolvable conditionals in the
+ * calculations. We also use round_up() as XFS_DIR2_DATA_ALIGN is always a power
+ * of 2 and the compiler doesn't reject it (unlike roundup()).
+ */
+#define XFS_DIR2_DATA_ENTSIZE(n) \
+ round_up((offsetof(struct xfs_dir2_data_entry, name[0]) + (n) + \
+ sizeof(xfs_dir2_data_off_t)), XFS_DIR2_DATA_ALIGN)
+
+#define XFS_DIR3_DATA_ENTSIZE(n) \
+ round_up((offsetof(struct xfs_dir2_data_entry, name[0]) + (n) + \
+ sizeof(xfs_dir2_data_off_t) + sizeof(__uint8_t)), \
+ XFS_DIR2_DATA_ALIGN)