diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 85a1528f319f2..2913483473f30 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -8,6 +8,7 @@
 #include <linux/fs.h>
 #include <linux/f2fs_fs.h>
 #include <linux/sched/signal.h>
+#include <linux/unicode.h>
 #include "f2fs.h"
 #include "node.h"
 #include "acl.h"
@@ -81,7 +82,8 @@ static unsigned long dir_block_index(unsigned int level,
 	return bidx;
 }
 
-static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
+static struct f2fs_dir_entry *find_in_block(struct inode *dir,
+				struct page *dentry_page,
 				struct fscrypt_name *fname,
 				f2fs_hash_t namehash,
 				int *max_slots,
@@ -93,7 +95,7 @@ static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
 
 	dentry_blk = (struct f2fs_dentry_block *)page_address(dentry_page);
 
-	make_dentry_ptr_block(NULL, &d, dentry_blk);
+	make_dentry_ptr_block(dir, &d, dentry_blk);
 	de = f2fs_find_target_dentry(fname, namehash, max_slots, &d);
 	if (de)
 		*res_page = dentry_page;
@@ -101,6 +103,39 @@ static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
 	return de;
 }
 
+#ifdef CONFIG_UNICODE
+/*
+ * Test whether a case-insensitive directory entry matches the filename
+ * being searched for.
+ *
+ * Returns: 0 if the directory entry matches, more than 0 if it
+ * doesn't match or less than zero on error.
+ */
+int f2fs_ci_compare(const struct inode *parent, const struct qstr *name,
+		    const struct qstr *entry)
+{
+	const struct f2fs_sb_info *sbi = F2FS_SB(parent->i_sb);
+	const struct unicode_map *um = sbi->s_encoding;
+	int ret;
+
+	ret = utf8_strncasecmp(um, name, entry);
+	if (ret < 0) {
+		/* Handle invalid character sequence as either an error
+		 * or as an opaque byte sequence.
+		 */
+		if (f2fs_has_strict_mode(sbi))
+			return -EINVAL;
+
+		if (name->len != entry->len)
+			return 1;
+
+		return !!memcmp(name->name, entry->name, name->len);
+	}
+
+	return ret;
+}
+#endif
+
 struct f2fs_dir_entry *f2fs_find_target_dentry(struct fscrypt_name *fname,
 			f2fs_hash_t namehash, int *max_slots,
 			struct f2fs_dentry_ptr *d)
@@ -108,6 +143,9 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(struct fscrypt_name *fname,
 	struct f2fs_dir_entry *de;
 	unsigned long bit_pos = 0;
 	int max_len = 0;
+#ifdef CONFIG_UNICODE
+	struct qstr entry;
+#endif
 
 	if (max_slots)
 		*max_slots = 0;
@@ -119,16 +157,28 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(struct fscrypt_name *fname,
 		}
 
 		de = &d->dentry[bit_pos];
+#ifdef CONFIG_UNICODE
+		entry.name = d->filename[bit_pos];
+		entry.len = de->name_len;
+#endif
 
 		if (unlikely(!de->name_len)) {
 			bit_pos++;
 			continue;
 		}
+		if (de->hash_code == namehash) {
+#ifdef CONFIG_UNICODE
+			if (F2FS_SB(d->inode->i_sb)->s_encoding &&
+					IS_CASEFOLDED(d->inode) &&
+					!f2fs_ci_compare(d->inode,
+						fname->usr_fname, &entry))
+				goto found;
 
-		if (de->hash_code == namehash &&
-		    fscrypt_match_name(fname, d->filename[bit_pos],
-				       le16_to_cpu(de->name_len)))
-			goto found;
+#endif
+			if (fscrypt_match_name(fname, d->filename[bit_pos],
+						le16_to_cpu(de->name_len)))
+				goto found;
+		}
 
 		if (max_slots && max_len > *max_slots)
 			*max_slots = max_len;
@@ -157,7 +207,7 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir,
 	struct f2fs_dir_entry *de = NULL;
 	bool room = false;
 	int max_slots;
-	f2fs_hash_t namehash = f2fs_dentry_hash(&name, fname);
+	f2fs_hash_t namehash = f2fs_dentry_hash(dir, &name, fname);
 
 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
 	nblock = bucket_blocks(level);
@@ -179,8 +229,8 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir,
 			}
 		}
 
-		de = find_in_block(dentry_page, fname, namehash, &max_slots,
-								res_page);
+		de = find_in_block(dir, dentry_page, fname, namehash,
+							&max_slots, res_page);
 		if (de)
 			break;
 
@@ -250,6 +300,14 @@ struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
 	struct fscrypt_name fname;
 	int err;
 
+#ifdef CONFIG_UNICODE
+	if (f2fs_has_strict_mode(F2FS_I_SB(dir)) && IS_CASEFOLDED(dir) &&
+			utf8_validate(F2FS_I_SB(dir)->s_encoding, child)) {
+		*res_page = ERR_PTR(-EINVAL);
+		return NULL;
+	}
+#endif
+
 	err = fscrypt_setup_filename(dir, child, 1, &fname);
 	if (err) {
 		if (err == -ENOENT)
@@ -504,7 +562,7 @@ int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
 
 	level = 0;
 	slots = GET_DENTRY_SLOTS(new_name->len);
-	dentry_hash = f2fs_dentry_hash(new_name, NULL);
+	dentry_hash = f2fs_dentry_hash(dir, new_name, NULL);
 
 	current_depth = F2FS_I(dir)->i_current_depth;
 	if (F2FS_I(dir)->chash == dentry_hash) {
@@ -943,3 +1001,51 @@ const struct file_operations f2fs_dir_operations = {
 	.compat_ioctl   = f2fs_compat_ioctl,
 #endif
 };
+
+#ifdef CONFIG_UNICODE
+static int f2fs_d_compare(const struct dentry *dentry, unsigned int len,
+			  const char *str, const struct qstr *name)
+{
+	struct qstr qstr = {.name = str, .len = len };
+
+	if (!IS_CASEFOLDED(dentry->d_parent->d_inode)) {
+		if (len != name->len)
+			return -1;
+		return memcmp(str, name, len);
+	}
+
+	return f2fs_ci_compare(dentry->d_parent->d_inode, name, &qstr);
+}
+
+static int f2fs_d_hash(const struct dentry *dentry, struct qstr *str)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
+	const struct unicode_map *um = sbi->s_encoding;
+	unsigned char *norm;
+	int len, ret = 0;
+
+	if (!IS_CASEFOLDED(dentry->d_inode))
+		return 0;
+
+	norm = f2fs_kmalloc(sbi, PATH_MAX, GFP_ATOMIC);
+	if (!norm)
+		return -ENOMEM;
+
+	len = utf8_casefold(um, str, norm, PATH_MAX);
+	if (len < 0) {
+		if (f2fs_has_strict_mode(sbi))
+			ret = -EINVAL;
+		goto out;
+	}
+	str->hash = full_name_hash(dentry, norm, len);
+out:
+	kvfree(norm);
+	return ret;
+}
+
+const struct dentry_operations f2fs_dentry_ops = {
+	.d_hash = f2fs_d_hash,
+	.d_compare = f2fs_d_compare,
+};
+#endif
+
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c6c7904572d0d..31fd2a268ba14 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2364,10 +2364,12 @@ static inline void f2fs_change_bit(unsigned int nr, char *addr)
 #define F2FS_INDEX_FL			0x00001000 /* hash-indexed directory */
 #define F2FS_DIRSYNC_FL			0x00010000 /* dirsync behaviour (directories only) */
 #define F2FS_PROJINHERIT_FL		0x20000000 /* Create with parents projid */
+#define F2FS_CASEFOLD_FL		0x40000000 /* Casefolded file */
 
 /* Flags that should be inherited by new inodes from their parent. */
 #define F2FS_FL_INHERITED (F2FS_SYNC_FL | F2FS_NODUMP_FL | F2FS_NOATIME_FL | \
-			   F2FS_DIRSYNC_FL | F2FS_PROJINHERIT_FL)
+			   F2FS_DIRSYNC_FL | F2FS_PROJINHERIT_FL | \
+			   F2FS_CASEFOLD_FL)
 
 /* Flags that are appropriate for regular files (all but dir-specific ones). */
 #define F2FS_REG_FLMASK		(~(F2FS_DIRSYNC_FL | F2FS_PROJINHERIT_FL))
@@ -2930,6 +2932,10 @@ int f2fs_update_extension_list(struct f2fs_sb_info *sbi, const char *name,
 							bool hot, bool set);
 struct dentry *f2fs_get_parent(struct dentry *child);
 
+extern int f2fs_ci_compare(const struct inode *parent,
+			   const struct qstr *name,
+			   const struct qstr *entry);
+
 /*
  * dir.c
  */
@@ -2993,8 +2999,8 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi);
 /*
  * hash.c
  */
-f2fs_hash_t f2fs_dentry_hash(const struct qstr *name_info,
-				struct fscrypt_name *fname);
+f2fs_hash_t f2fs_dentry_hash(const struct inode *dir,
+		const struct qstr *name_info, struct fscrypt_name *fname);
 
 /*
  * node.c
@@ -3437,6 +3443,9 @@ static inline void f2fs_destroy_root_stats(void) { }
 #endif
 
 extern const struct file_operations f2fs_dir_operations;
+#ifdef CONFIG_UNICODE
+extern const struct dentry_operations f2fs_dentry_ops;
+#endif
 extern const struct file_operations f2fs_file_operations;
 extern const struct inode_operations f2fs_file_inode_operations;
 extern const struct address_space_operations f2fs_dblock_aops;
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index f8d46df8fa9ee..7adef2d8dbc47 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1660,7 +1660,16 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
 		return -EPERM;
 
 	oldflags = fi->i_flags;
+	if ((iflags ^ oldflags) & F2FS_CASEFOLD_FL) {
+		if (!f2fs_sb_has_casefold(F2FS_I_SB(inode)))
+			return -EOPNOTSUPP;
+
+		if (!S_ISDIR(inode->i_mode))
+			return -ENOTDIR;
 
+		if (!f2fs_empty_dir(inode))
+			return -ENOTEMPTY;
+	}
 	if ((iflags ^ oldflags) & (F2FS_APPEND_FL | F2FS_IMMUTABLE_FL))
 		if (!capable(CAP_LINUX_IMMUTABLE))
 			return -EPERM;
diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c
index cc82f142f811f..b7bd0ddbbdf01 100644
--- a/fs/f2fs/hash.c
+++ b/fs/f2fs/hash.c
@@ -14,6 +14,7 @@
 #include <linux/f2fs_fs.h>
 #include <linux/cryptohash.h>
 #include <linux/pagemap.h>
+#include <linux/unicode.h>
 
 #include "f2fs.h"
 
@@ -67,7 +68,7 @@ static void str2hashbuf(const unsigned char *msg, size_t len,
 		*buf++ = pad;
 }
 
-f2fs_hash_t f2fs_dentry_hash(const struct qstr *name_info,
+static f2fs_hash_t __f2fs_dentry_hash(const struct qstr *name_info,
 				struct fscrypt_name *fname)
 {
 	__u32 hash;
@@ -103,3 +104,35 @@ f2fs_hash_t f2fs_dentry_hash(const struct qstr *name_info,
 	f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT);
 	return f2fs_hash;
 }
+
+f2fs_hash_t f2fs_dentry_hash(const struct inode *dir,
+		const struct qstr *name_info, struct fscrypt_name *fname)
+{
+#ifdef CONFIG_UNICODE
+	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
+	const struct unicode_map *um = sbi->s_encoding;
+	int r, dlen;
+	unsigned char *buff;
+	struct qstr *folded;
+
+	if (name_info->len && IS_CASEFOLDED(dir)) {
+		buff = f2fs_kzalloc(sbi, sizeof(char) * PATH_MAX, GFP_KERNEL);
+		if (!buff)
+			return -ENOMEM;
+
+		dlen = utf8_casefold(um, name_info, buff, PATH_MAX);
+		if (dlen < 0) {
+			kfree(buff);
+			goto opaque_seq;
+		}
+		folded->name = buff;
+		folded->len = dlen;
+		r = __f2fs_dentry_hash(folded, fname);
+
+		kvfree(buff);
+		return r;
+	}
+opaque_seq:
+#endif
+	return __f2fs_dentry_hash(name_info, fname);
+}
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 3613efca8c00c..354f71cf9e6ba 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -320,7 +320,7 @@ struct f2fs_dir_entry *f2fs_find_in_inline_dir(struct inode *dir,
 		return NULL;
 	}
 
-	namehash = f2fs_dentry_hash(&name, fname);
+	namehash = f2fs_dentry_hash(dir, &name, fname);
 
 	inline_dentry = inline_data_addr(dir, ipage);
 
@@ -580,7 +580,7 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *new_name,
 
 	f2fs_wait_on_page_writeback(ipage, NODE, true, true);
 
-	name_hash = f2fs_dentry_hash(new_name, NULL);
+	name_hash = f2fs_dentry_hash(dir, new_name, NULL);
 	f2fs_update_dentry(ino, mode, &d, new_name, name_hash, bit_pos);
 
 	set_page_dirty(ipage);
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index a33d7a849b2df..9a1f0d6616577 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -46,9 +46,11 @@ void f2fs_set_inode_flags(struct inode *inode)
 		new_fl |= S_DIRSYNC;
 	if (file_is_encrypt(inode))
 		new_fl |= S_ENCRYPTED;
+	if (flags & F2FS_CASEFOLD_FL)
+		new_fl |= S_CASEFOLD;
 	inode_set_flags(inode, new_fl,
 			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|
-			S_ENCRYPTED);
+			S_ENCRYPTED|S_CASEFOLD);
 }
 
 static void __get_inode_rdev(struct inode *inode, struct f2fs_inode *ri)
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index c5b99042e6f2b..727de2f8620f2 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -489,6 +489,17 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 		goto out_iput;
 	}
 out_splice:
+#ifdef CONFIG_UNICODE
+	if (!inode && IS_CASEFOLDED(dir)) {
+		/* Eventually we want to call d_add_ci(dentry, NULL)
+		 * for negative dentries in the encoding case as
+		 * well.  For now, prevent the negative dentry
+		 * from being cached.
+		 */
+		trace_f2fs_lookup_end(dir, dentry, ino, err);
+		return NULL;
+	}
+#endif
 	new = d_splice_alias(inode, dentry);
 	err = PTR_ERR_OR_ZERO(new);
 	trace_f2fs_lookup_end(dir, dentry, ino, err);
@@ -537,6 +548,16 @@ static int f2fs_unlink(struct inode *dir, struct dentry *dentry)
 		goto fail;
 	}
 	f2fs_delete_entry(de, page, dir, inode);
+#ifdef CONFIG_UNICODE
+	/* VFS negative dentries are incompatible with Encoding and
+	 * Case-insensitiveness. Eventually we'll want avoid
+	 * invalidating the dentries here, alongside with returning the
+	 * negative dentries at f2fs_lookup(), when it is  better
+	 * supported by the VFS for the CI case.
+	 */
+	if (IS_CASEFOLDED(dir))
+		d_invalidate(dentry);
+#endif
 	f2fs_unlock_op(sbi);
 
 	if (IS_DIRSYNC(dir))
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 82f7da93c3ed1..9c522d1abcb6d 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3115,6 +3115,7 @@ static int f2fs_setup_casefold(struct f2fs_sb_info *sbi)
 		return -EINVAL;
 	}
 #endif
+	return 0;
 }
 
 static void f2fs_tuning_parameters(struct f2fs_sb_info *sbi)
@@ -3410,6 +3411,11 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		goto free_node_inode;
 	}
 
+#ifdef CONFIG_UNICODE
+	if (sbi->s_encoding)
+		sb->s_d_op = &f2fs_dentry_ops;
+#endif
+
 	sb->s_root = d_make_root(root); /* allocate root dentry */
 	if (!sb->s_root) {
 		err = -ENOMEM;
