diff --git a/fs/xfs/libxfs/xfs_dir2.c b/fs/xfs/libxfs/xfs_dir2.c
index 92bac3373f1f..f5462fd582d5 100644
--- a/fs/xfs/libxfs/xfs_dir2.c
+++ b/fs/xfs/libxfs/xfs_dir2.c
@@ -64,7 +64,7 @@ xfs_ascii_ci_hashname(
 	int			i;
 
 	for (i = 0, hash = 0; i < name->len; i++)
-		hash = tolower(name->name[i]) ^ rol32(hash, 7);
+		hash = xfs_ascii_ci_xfrm(name->name[i]) ^ rol32(hash, 7);
 
 	return hash;
 }
@@ -85,7 +85,8 @@ xfs_ascii_ci_compname(
 	for (i = 0; i < len; i++) {
 		if (args->name[i] == name[i])
 			continue;
-		if (tolower(args->name[i]) != tolower(name[i]))
+		if (xfs_ascii_ci_xfrm(args->name[i]) !=
+		    xfs_ascii_ci_xfrm(name[i]))
 			return XFS_CMP_DIFFERENT;
 		result = XFS_CMP_CASE;
 	}
diff --git a/fs/xfs/libxfs/xfs_dir2.h b/fs/xfs/libxfs/xfs_dir2.h
index dd39f17dd9a9..19af22a16c41 100644
--- a/fs/xfs/libxfs/xfs_dir2.h
+++ b/fs/xfs/libxfs/xfs_dir2.h
@@ -248,4 +248,35 @@ unsigned int xfs_dir3_data_end_offset(struct xfs_da_geometry *geo,
 		struct xfs_dir2_data_hdr *hdr);
 bool xfs_dir2_namecheck(const void *name, size_t length);
 
+/*
+ * The "ascii-ci" feature was created to speed up case-insensitive lookups for
+ * a Samba product.  Because of the inherent problems with CI and UTF-8
+ * encoding, etc, it was decided that Samba would be configured to export
+ * latin1/iso 8859-1 encodings as that covered >90% of the target markets for
+ * the product.  Hence the "ascii-ci" casefolding code could be encoded into
+ * the XFS directory operations and remove all the overhead of casefolding from
+ * Samba.
+ *
+ * To provide consistent hashing behavior between the userspace and kernel,
+ * these functions prepare names for hashing by transforming specific bytes
+ * to other bytes.  Robustness with other encodings is not guaranteed.
+ */
+static inline bool xfs_ascii_ci_need_xfrm(unsigned char c)
+{
+	if (c >= 0x41 && c <= 0x5a)	/* A-Z */
+		return true;
+	if (c >= 0xc0 && c <= 0xd6)	/* latin A-O with accents */
+		return true;
+	if (c >= 0xd8 && c <= 0xde)	/* latin O-Y with accents */
+		return true;
+	return false;
+}
+
+static inline unsigned char xfs_ascii_ci_xfrm(unsigned char c)
+{
+	if (xfs_ascii_ci_need_xfrm(c))
+		c -= 'A' - 'a';
+	return c;
+}
+
 #endif	/* __XFS_DIR2_H__ */