+struct lov_version_size {
+ __u32 lvs_magic;
+ size_t lvs_lmm_size;
+ size_t lvs_lod_size;
+};
+
+static inline __u32 lov_mds_md_stripecnt(int ea_size, __u32 lmm_magic)
+{
+ static const struct lov_version_size lmm_ver_size[] = {
+ { .lvs_magic = LOV_MAGIC_V3,
+ .lvs_lmm_size = sizeof(struct lov_mds_md_v3),
+ .lvs_lod_size = sizeof(struct lov_ost_data_v1) },
+ { .lvs_magic = LOV_MAGIC_V1,
+ .lvs_lmm_size = sizeof(struct lov_mds_md_v1),
+ .lvs_lod_size = sizeof(struct lov_ost_data_v1)} };
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(lmm_ver_size); i++) {
+ if (lmm_magic == lmm_ver_size[i].lvs_magic) {
+ if (ea_size <= lmm_ver_size[i].lvs_lmm_size)
+ return 0;
+ return (ea_size - lmm_ver_size[i].lvs_lmm_size) /
+ lmm_ver_size[i].lvs_lod_size;
+ }
+ }
+
+ /* Invalid LOV magic, so no stripes could fit */
+ return 0;
+}
+
+/* lov_do_div64(a, b) returns a % b, and a = a / b.
+ * The 32-bit code is LOV-specific due to knowing about stripe limits in
+ * order to reduce the divisor to a 32-bit number. If the divisor is
+ * already a 32-bit value the compiler handles this directly. */
+#if BITS_PER_LONG > 32
+# define lov_do_div64(n,base) ({ \
+ uint64_t __base = (base); \
+ uint64_t __rem; \
+ __rem = ((uint64_t)(n)) % __base; \
+ (n) = ((uint64_t)(n)) / __base; \
+ __rem; \
+ })
+#else
+# define lov_do_div64(n,base) ({ \
+ uint64_t __rem; \
+ if ((sizeof(base) > 4) && (((base) & 0xffffffff00000000ULL) != 0)) { \
+ int __remainder; \
+ LASSERTF(!((base) & (LOV_MIN_STRIPE_SIZE - 1)), "64 bit lov " \
+ "division %llu / %llu\n", (n), (uint64_t)(base)); \
+ __remainder = (n) & (LOV_MIN_STRIPE_SIZE - 1); \
+ (n) >>= LOV_MIN_STRIPE_BITS; \
+ __rem = do_div(n, (base) >> LOV_MIN_STRIPE_BITS); \
+ __rem <<= LOV_MIN_STRIPE_BITS; \
+ __rem += __remainder; \
+ } else { \
+ __rem = do_div(n, base); \
+ } \
+ __rem; \
+ })
+#endif
+