this patch implements feature which allows ext4 fs users (e.g. Lustre)
to store data in ext4 dirent.
data is stored in ext4 dirent after file-name, this space is accounted
in de->rec_len. flag EXT4_DIRENT_LUFID added to d_type if extra data
is present.

make use of dentry->d_fsdata to pass fid to ext4. so no
changes in ext4_add_entry() interface required.

diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 9fdd2b2..2a73a69 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -77,7 +77,7 @@ int __ext4_check_dir_entry(const char *function, unsigned int line,
 		error_msg = "rec_len is smaller than minimal";
 	else if (unlikely(rlen % 4 != 0))
 		error_msg = "rec_len % 4 != 0";
-	else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
+	else if (unlikely(rlen < EXT4_DIR_ENTRY_LEN(de)))
 		error_msg = "rec_len is too small for name_len";
 	else if (unlikely(((char *) de - buf) + rlen > size))
 		error_msg = "directory entry overrun";
@@ -220,7 +220,7 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
 				 * failure will be detected in the
 				 * dirent test below. */
 				if (ext4_rec_len_from_disk(de->rec_len,
-					sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
+				    sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
 					break;
 				i += ext4_rec_len_from_disk(de->rec_len,
 							    sb->s_blocksize);
@@ -443,12 +443,17 @@ int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 	struct fname *fname, *new_fn;
 	struct dir_private_info *info;
 	int len;
+	int extra_data = 0;
 
 	info = dir_file->private_data;
 	p = &info->root.rb_node;
 
 	/* Create and allocate the fname structure */
-	len = sizeof(struct fname) + ent_name->len + 1;
+	if (dirent->file_type & EXT4_DIRENT_LUFID)
+		extra_data = ext4_get_dirent_data_len(dirent);
+
+	len = sizeof(struct fname) + ent_name->len + extra_data + 1;
+
 	new_fn = kzalloc(len, GFP_KERNEL);
 	if (!new_fn)
 		return -ENOMEM;
@@ -457,7 +462,7 @@ int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 	new_fn->inode = le32_to_cpu(dirent->inode);
 	new_fn->name_len = ent_name->len;
 	new_fn->file_type = dirent->file_type;
-	memcpy(new_fn->name, ent_name->name, ent_name->len);
+	memcpy(new_fn->name, ent_name->name, ent_name->len + extra_data);
 	new_fn->name[ent_name->len] = 0;
 
 	while (*p) {
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index cb649f0..fe35251 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1094,6 +1094,7 @@ struct ext4_inode_info {
 	__u32 i_csum_seed;
 
 	kprojid_t i_projid;
+	void *i_dirdata;
 };
 
 /*
@@ -1114,6 +1115,7 @@
  * Mount flags set via mount options or defaults
  */
 #define EXT4_MOUNT_NO_MBCACHE		0x00001 /* Do not use mbcache */
+#define EXT4_MOUNT_DIRDATA		0x00002	/* Data in directory entries */
 #define EXT4_MOUNT_GRPID		0x00004	/* Create files with directory's group */
 #define EXT4_MOUNT_DEBUG		0x00008	/* Some debugging messages */
 #define EXT4_MOUNT_ERRORS_CONT		0x00010	/* Continue on errors */
@@ -1843,6 +1845,7 @@
 					 EXT4_FEATURE_INCOMPAT_FLEX_BG| \
 					 EXT4_FEATURE_INCOMPAT_EA_INODE| \
 					 EXT4_FEATURE_INCOMPAT_MMP | \
+					 EXT4_FEATURE_INCOMPAT_DIRDATA| \
 					 EXT4_FEATURE_INCOMPAT_INLINE_DATA | \
 					 EXT4_FEATURE_INCOMPAT_ENCRYPT | \
 					 EXT4_FEATURE_INCOMPAT_CASEFOLD | \
@@ -2020,6 +2023,43 @@ struct ext4_dir_entry_tail {
 #define EXT4_FT_SYMLINK		7
 
 #define EXT4_FT_MAX		8
+#define EXT4_FT_MASK		0xf
+
+#if EXT4_FT_MAX > EXT4_FT_MASK
+#error "conflicting EXT4_FT_MAX and EXT4_FT_MASK"
+#endif
+
+/*
+ * d_type has 4 unused bits, so it can hold four types data. these different
+ * type of data (e.g. lustre data, high 32 bits of 64-bit inode number) can be
+ * stored, in flag order, after file-name in ext4 dirent.
+*/
+/*
+ * this flag is added to d_type if ext4 dirent has extra data after
+ * filename. this data length is variable and length is stored in first byte
+ * of data. data start after filename NUL byte.
+ * This is used by Lustre FS.
+  */
+#define EXT4_DIRENT_LUFID		0x10
+
+#define EXT4_LUFID_MAGIC    0xAD200907UL
+struct ext4_dentry_param {
+	__u32  edp_magic;	/* EXT4_LUFID_MAGIC */
+	char   edp_len;		/* size of edp_data in bytes */
+	char   edp_data[0];	/* packed array of data */
+} __packed;
+
+static inline unsigned char *ext4_dentry_get_data(struct super_block *sb,
+						  struct ext4_dentry_param *p)
+
+{
+	if (!ext4_has_feature_dirdata(sb))
+		return NULL;
+	if (p && p->edp_magic == EXT4_LUFID_MAGIC)
+		return &p->edp_len;
+	else
+		return NULL;
+}
 
 #define EXT4_FT_DIR_CSUM	0xDE
 
@@ -2030,8 +2070,16 @@ struct ext4_dir_entry_tail {
  */
 #define EXT4_DIR_PAD			4
 #define EXT4_DIR_ROUND			(EXT4_DIR_PAD - 1)
-#define EXT4_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT4_DIR_ROUND) & \
+#define EXT4_DIR_REC_LEN_(name_len)	(((name_len) + 8 + EXT4_DIR_ROUND) & \
 					 ~EXT4_DIR_ROUND)
+#define EXT4_DIR_ENTRY_LEN_(de)		(EXT4_DIR_REC_LEN_((de)->name_len +\
+					ext4_get_dirent_data_len(de)))
+/* ldiskfs */
+#define EXT4_DIR_REC_LEN(name_len)	EXT4_DIR_REC_LEN_((name_len))
+#define EXT4_DIR_ENTRY_LEN(de)		EXT4_DIR_ENTRY_LEN_((de))
+/* lustre osd_handler compat */
+#define __EXT4_DIR_REC_LEN(name_len)	EXT4_DIR_REC_LEN_((name_len))
+
 #define EXT4_MAX_REC_LEN		((1<<16)-1)
 
 /*
@@ -2491,11 +2539,11 @@ extern int ext4_find_dest_de(struct inode *dir, struct inode *inode,
 			     struct buffer_head *bh,
 			     void *buf, int buf_size,
 			     struct ext4_filename *fname,
-			     struct ext4_dir_entry_2 **dest_de);
+			     struct ext4_dir_entry_2 **dest_de, int *dlen);
 void ext4_insert_dentry(struct inode *inode,
 			struct ext4_dir_entry_2 *de,
 			int buf_size,
-			struct ext4_filename *fname);
+ 		        struct ext4_filename *fname, void *data);
 static inline void ext4_update_dx_flag(struct inode *inode)
 {
 	if (!ext4_has_feature_dir_index(inode->i_sb))
@@ -2507,10 +2555,17 @@ static const unsigned char ext4_filetype_table[] = {
 
 static inline  unsigned char get_dtype(struct super_block *sb, int filetype)
 {
-	if (!ext4_has_feature_filetype(sb) || filetype >= EXT4_FT_MAX)
+	int fl_index = filetype & EXT4_FT_MASK;
+
+	if (!ext4_has_feature_filetype(sb) || fl_index >= EXT4_FT_MAX)
 		return DT_UNKNOWN;
 
-	return ext4_filetype_table[filetype];
+	if (!test_opt(sb, DIRDATA))
+		return ext4_filetype_table[fl_index];
+
+	return (ext4_filetype_table[fl_index]) |
+		(filetype & EXT4_DIRENT_LUFID);
+
 }
 extern int ext4_check_all_de(struct inode *dir, struct buffer_head *bh,
 			     void *buf, int buf_size);
@@ -2673,6 +2728,8 @@ extern struct inode *ext4_create_inode(handle_t *handle,
 extern int ext4_delete_entry(handle_t *handle, struct inode * dir,
 			     struct ext4_dir_entry_2 *de_del,
 			     struct buffer_head *bh);
+extern int ext4_add_dot_dotdot(handle_t *handle, struct inode *dir,
+			       struct inode *inode, const void *, const void *);
 extern int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
 				__u32 start_minor_hash, __u32 *next_hash);
 extern int ext4_search_dir(struct buffer_head *bh,
@@ -3428,6 +3485,36 @@ static inline int ext4_buffer_uptodate(struct buffer_head *bh)
 	return buffer_uptodate(bh);
 }
 
+/*
+ * Compute the total directory entry data length.
+ * This includes the filename and an implicit NUL terminator (always present),
+ * and optional extensions.  Each extension has a bit set in the high 4 bits of
+ * de->file_type, and the extension length is the first byte in each entry.
+ */
+static inline int ext4_get_dirent_data_len(struct ext4_dir_entry_2 *de)
+{
+	char *len = de->name + de->name_len + 1 /* NUL terminator */;
+	int dlen = 0;
+	__u8 extra_data_flags = (de->file_type & ~EXT4_FT_MASK) >> 4;
+	struct ext4_dir_entry_tail *t = (struct ext4_dir_entry_tail *)de;
+
+	if (!t->det_reserved_zero1 &&
+	    le16_to_cpu(t->det_rec_len) ==
+		sizeof(struct ext4_dir_entry_tail) &&
+	    !t->det_reserved_zero2 &&
+	    t->det_reserved_ft == EXT4_FT_DIR_CSUM)
+		return 0;
+
+	while (extra_data_flags) {
+		if (extra_data_flags & 1) {
+			dlen += *len + (dlen == 0);
+			len += *len;
+		}
+		extra_data_flags >>= 1;
+	}
+	return dlen;
+}
+
 #endif	/* __KERNEL__ */
 
 #define EFSBADCRC	EBADMSG		/* Bad CRC detected */
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 2fec62d..3f35821 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1023,7 +1023,7 @@ static int ext4_add_dirent_to_inline(handle_t *handle,
 	struct ext4_dir_entry_2 *de;
 
 	err = ext4_find_dest_de(dir, inode, iloc->bh, inline_start,
-				inline_size, fname, &de);
+				inline_size, fname, &de, NULL);
 	if (err)
 		return err;
 
@@ -1031,7 +1031,7 @@ static int ext4_add_dirent_to_inline(handle_t *handle,
 	err = ext4_journal_get_write_access(handle, iloc->bh);
 	if (err)
 		return err;
-	ext4_insert_dentry(inode, de, inline_size, fname);
+	ext4_insert_dentry(inode, de, inline_size, fname, NULL);
 
 	ext4_show_inline_dir(dir, iloc->bh, inline_start, inline_size);
 
@@ -1378,7 +1378,7 @@ int ext4_inlinedir_to_tree(struct file *dir_file,
 			fake.name_len = 1;
 			strcpy(fake.name, ".");
 			fake.rec_len = ext4_rec_len_to_disk(
-						EXT4_DIR_REC_LEN(fake.name_len),
+						EXT4_DIR_ENTRY_LEN(&fake),
 						inline_size);
 			ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
 			de = &fake;
@@ -1388,7 +1388,7 @@ int ext4_inlinedir_to_tree(struct file *dir_file,
 			fake.name_len = 2;
 			strcpy(fake.name, "..");
 			fake.rec_len = ext4_rec_len_to_disk(
-						EXT4_DIR_REC_LEN(fake.name_len),
+						EXT4_DIR_ENTRY_LEN(&fake),
 						inline_size);
 			ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
 			de = &fake;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 8713671..23bd871 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -258,7 +258,8 @@ static unsigned dx_get_count(struct dx_entry *entries);
 static unsigned dx_get_limit(struct dx_entry *entries);
 static void dx_set_count(struct dx_entry *entries, unsigned value);
 static void dx_set_limit(struct dx_entry *entries, unsigned value);
-static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
+static inline unsigned dx_root_limit(struct inode *dir,
+		struct ext4_dir_entry_2 *dot_de, unsigned infosize);
 static unsigned dx_node_limit(struct inode *dir);
 static struct dx_frame *dx_probe(struct ext4_filename *fname,
 				 struct inode *dir,
@@ -402,22 +403,23 @@ static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
 {
 	struct ext4_dir_entry *dp;
 	struct dx_root_info *root;
-	int count_offset;
+	int count_offset, dot_rec_len, dotdot_rec_len;
 
 	if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb))
 		count_offset = 8;
-	else if (le16_to_cpu(dirent->rec_len) == 12) {
-		dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
+	else {
+		dot_rec_len = le16_to_cpu(dirent->rec_len);
+		dp = (struct ext4_dir_entry *)(((void *)dirent) + dot_rec_len);
 		if (le16_to_cpu(dp->rec_len) !=
-		    EXT4_BLOCK_SIZE(inode->i_sb) - 12)
+		    EXT4_BLOCK_SIZE(inode->i_sb) - dot_rec_len)
 			return NULL;
-		root = (struct dx_root_info *)(((void *)dp + 12));
+		dotdot_rec_len = EXT4_DIR_ENTRY_LEN((struct ext4_dir_entry_2 *)dp);
+		root = (struct dx_root_info *)(((void *)dp + dotdot_rec_len));
 		if (root->reserved_zero ||
 		    root->info_length != sizeof(struct dx_root_info))
 			return NULL;
-		count_offset = 32;
-	} else
-		return NULL;
+		count_offset = 8 + dot_rec_len + dotdot_rec_len;
+	}
 
 	if (offset)
 		*offset = count_offset;
@@ -522,11 +524,12 @@ ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
  */
 struct dx_root_info *dx_get_dx_info(struct ext4_dir_entry_2 *de)
 {
+	BUG_ON(de->name_len != 1);
 	/* get dotdot first */
-	de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(1));
+	de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_ENTRY_LEN(de));
 
 	/* dx root info is after dotdot entry */
-	de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(2));
+	de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_ENTRY_LEN(de));
 
 	return (struct dx_root_info *)de;
 }
@@ -571,10 +574,16 @@ static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
 	((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
 }
 
-static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
+static inline unsigned dx_root_limit(struct inode *dir,
+		struct ext4_dir_entry_2 *dot_de, unsigned infosize)
 {
-	unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
-		EXT4_DIR_REC_LEN(2) - infosize;
+	struct ext4_dir_entry_2 *dotdot_de;
+	unsigned entry_space;
+
+	BUG_ON(dot_de->name_len != 1);
+	dotdot_de = ext4_next_entry(dot_de, dir->i_sb->s_blocksize);
+	entry_space = dir->i_sb->s_blocksize - EXT4_DIR_ENTRY_LEN(dot_de) -
+			 EXT4_DIR_ENTRY_LEN(dotdot_de) - infosize;
 
 	if (ext4_has_metadata_csum(dir->i_sb))
 		entry_space -= sizeof(struct dx_tail);
@@ -695,7 +704,7 @@ static struct stats dx_show_leaf(struct inode *dir,
 				       (unsigned) ((char *) de - base));
 #endif
 			}
-			space += EXT4_DIR_REC_LEN(de->name_len);
+			space += EXT4_DIR_ENTRY_LEN(de);
 			names++;
 		}
 		de = ext4_next_entry(de, size);
@@ -802,11 +811,14 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
 
 	entries = (struct dx_entry *)(((char *)info) + info->info_length);
 
-	if (dx_get_limit(entries) != dx_root_limit(dir,
-						   info->info_length)) {
+	if (dx_get_limit(entries) !=
+	    dx_root_limit(dir, (struct ext4_dir_entry_2 *)frame->bh->b_data,
+			  info->info_length)) {
 		ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
 				   dx_get_limit(entries),
-				   dx_root_limit(dir, info->info_length));
+				   dx_root_limit(dir,
+					  (struct ext4_dir_entry_2 *)frame->bh->b_data,
+					  info->info_length));
 		goto fail;
 	}
 
@@ -1792,7 +1804,7 @@ dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
 	while (count--) {
 		struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
 						(from + (map->offs<<2));
-		rec_len = EXT4_DIR_REC_LEN(de->name_len);
+		rec_len = EXT4_DIR_ENTRY_LEN(de);
 		memcpy (to, de, rec_len);
 		((struct ext4_dir_entry_2 *) to)->rec_len =
 				ext4_rec_len_to_disk(rec_len, blocksize);
@@ -1816,7 +1828,7 @@ static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
 	while ((char*)de < base + blocksize) {
 		next = ext4_next_entry(de, blocksize);
 		if (de->inode && de->name_len) {
-			rec_len = EXT4_DIR_REC_LEN(de->name_len);
+			rec_len = EXT4_DIR_ENTRY_LEN(de);
 			if (de > to)
 				memmove(to, de, rec_len);
 			to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
@@ -1943,14 +1955,16 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode,
 		      struct buffer_head *bh,
 		      void *buf, int buf_size,
 		      struct ext4_filename *fname,
-		      struct ext4_dir_entry_2 **dest_de)
+		      struct ext4_dir_entry_2 **dest_de, int *dlen)
 {
 	struct ext4_dir_entry_2 *de;
-	unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
+	unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname)) +
+						  (dlen ? *dlen : 0);
 	int nlen, rlen;
 	unsigned int offset = 0;
 	char *top;
 
+	dlen ? *dlen = 0 : 0; /* default set to 0 */
 	de = (struct ext4_dir_entry_2 *)buf;
 	top = buf + buf_size - reclen;
 	while ((char *) de <= top) {
@@ -1959,10 +1973,26 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode,
 			return -EFSCORRUPTED;
 		if (ext4_match(dir, fname, de))
 			return -EEXIST;
-		nlen = EXT4_DIR_REC_LEN(de->name_len);
+		nlen = EXT4_DIR_ENTRY_LEN(de);
 		rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
 		if ((de->inode ? rlen - nlen : rlen) >= reclen)
 			break;
+		/* Then for dotdot entries, check for the smaller space
+		 * required for just the entry, no FID */
+		if (fname_len(fname) == 2 && memcmp(fname_name(fname), "..", 2) == 0) {
+			if ((de->inode ? rlen - nlen : rlen) >=
+			    EXT4_DIR_REC_LEN(fname_len(fname))) {
+				/* set dlen=1 to indicate not
+				 * enough space store fid */
+				dlen ? *dlen = 1 : 0;
+				break;
+			}
+			/* The new ".." entry must be written over the
+			 * previous ".." entry, which is the first
+			 * entry traversed by this scan. If it doesn't
+			 * fit, something is badly wrong, so -EIO. */
+			return -EIO;
+		}
 		de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
 		offset += rlen;
 	}
@@ -1976,12 +2006,12 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode,
 void ext4_insert_dentry(struct inode *inode,
 			struct ext4_dir_entry_2 *de,
 			int buf_size,
-			struct ext4_filename *fname)
+ 		        struct ext4_filename *fname, void *data)
 {
 
 	int nlen, rlen;
 
-	nlen = EXT4_DIR_REC_LEN(de->name_len);
+	nlen = EXT4_DIR_ENTRY_LEN(de);
 	rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
 	if (de->inode) {
 		struct ext4_dir_entry_2 *de1 =
@@ -1995,6 +2025,11 @@ void ext4_insert_dentry(struct inode *inode,
 	ext4_set_de_type(inode->i_sb, de, inode->i_mode);
 	de->name_len = fname_len(fname);
 	memcpy(de->name, fname_name(fname), fname_len(fname));
+	if (data) {
+		de->name[fname_len(fname)] = 0;
+		memcpy(&de->name[fname_len(fname) + 1], data, *(char *)data);
+		de->file_type |= EXT4_DIRENT_LUFID;
+	}
 }
 
 /*
@@ -2012,14 +2047,19 @@ static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
 {
 	unsigned int	blocksize = dir->i_sb->s_blocksize;
 	int		csum_size = 0;
-	int		err;
+	int		err, dlen = 0;
+	unsigned char	*data;
 
+	data = ext4_dentry_get_data(inode->i_sb, (struct ext4_dentry_param *)
+						EXT4_I(inode)->i_dirdata);
 	if (ext4_has_metadata_csum(inode->i_sb))
 		csum_size = sizeof(struct ext4_dir_entry_tail);
 
 	if (!de) {
+		if (data)
+			dlen = (*data) + 1;
 		err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
-					blocksize - csum_size, fname, &de);
+					blocksize - csum_size, fname, &de, &dlen);
 		if (err)
 			return err;
 	}
@@ -2031,7 +2071,10 @@ static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
 	}
 
 	/* By now the buffer is marked for journaling */
-	ext4_insert_dentry(inode, de, blocksize, fname);
+	/* If writing the short form of "dotdot", don't add the data section */
+	if (dlen == 1)
+		data = NULL;
+	ext4_insert_dentry(inode, de, blocksize, fname, data);
 
 	/*
 	 * XXX shouldn't update any times until successful
@@ -2136,7 +2179,8 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
 
 	dx_set_block(entries, 1);
 	dx_set_count(entries, 1);
-	dx_set_limit(entries, dx_root_limit(dir, sizeof(*dx_info)));
+	dx_set_limit(entries, dx_root_limit(dir,
+					 dot_de, sizeof(*dx_info)));
 
 	/* Initialize as for dx_probe */
 	fname->hinfo.hash_version = dx_info->hash_version;
@@ -2186,6 +2230,8 @@ static int ext4_update_dotdot(handle_t *handle, struct dentry *dentry,
 	struct buffer_head *dir_block;
 	struct ext4_dir_entry_2 *de;
 	int len, journal = 0, err = 0;
+	int dlen = 0;
+	char *data;
 
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
@@ -2211,11 +2257,16 @@ static int ext4_update_dotdot(handle_t *handle, struct dentry *dentry,
 			goto out_journal;
 
 		journal = 1;
-		de->rec_len = cpu_to_le16(EXT4_DIR_REC_LEN(1));
+		de->rec_len = cpu_to_le16(EXT4_DIR_ENTRY_LEN(de));
 	}
 
-	len -= EXT4_DIR_REC_LEN(1);
-	assert(len == 0 || len >= EXT4_DIR_REC_LEN(2));
+	len -= EXT4_DIR_ENTRY_LEN(de);
+	data = ext4_dentry_get_data(dir->i_sb,
+			(struct ext4_dentry_param *)dentry->d_fsdata);
+	if (data)
+		dlen = *data + 1;
+	assert(len == 0 || len >= EXT4_DIR_REC_LEN(2 + dlen));
+
 	de = (struct ext4_dir_entry_2 *)
 			((char *) de + le16_to_cpu(de->rec_len));
 	if (!journal) {
@@ -2232,7 +2283,12 @@ static int ext4_update_dotdot(handle_t *handle, struct dentry *dentry,
 		assert(le16_to_cpu(de->rec_len) >= EXT4_DIR_REC_LEN(2));
 	de->name_len = 2;
 	strcpy(de->name, "..");
-	ext4_set_de_type(dir->i_sb, de, S_IFDIR);
+	if (data != NULL && ext4_get_dirent_data_len(de) >= dlen) {
+		de->name[2] = 0;
+		memcpy(&de->name[2 + 1], data, *data);
+		ext4_set_de_type(dir->i_sb, de, S_IFDIR);
+		de->file_type |= EXT4_DIRENT_LUFID;
+	}
 
 out_journal:
 	if (journal) {
@@ -2271,6 +2327,7 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
 	ext4_lblk_t block, blocks;
 	int	csum_size = 0;
 
+	EXT4_I(inode)->i_dirdata = dentry->d_fsdata;
 	if (ext4_has_metadata_csum(inode->i_sb))
 		csum_size = sizeof(struct ext4_dir_entry_tail);
 
@@ -2803,37 +2860,70 @@ err_unlock_inode:
 	return err;
 }
 
+struct tp_block {
+	struct inode *inode;
+	void *data1;
+	void *data2;
+};
+
 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
 			  struct ext4_dir_entry_2 *de,
 			  int blocksize, int csum_size,
 			  unsigned int parent_ino, int dotdot_real_len)
 {
+	void *data1 = NULL, *data2 = NULL;
+	int dot_reclen = 0;
+
+	if (dotdot_real_len == 10) {
+		struct tp_block *tpb = (struct tp_block *)inode;
+		data1 = tpb->data1;
+		data2 = tpb->data2;
+		inode = tpb->inode;
+		dotdot_real_len = 0;
+	}
 	de->inode = cpu_to_le32(inode->i_ino);
 	de->name_len = 1;
-	de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
-					   blocksize);
 	strcpy(de->name, ".");
 	ext4_set_de_type(inode->i_sb, de, S_IFDIR);
 
+	/* get packed fid data*/
+	data1 = ext4_dentry_get_data(inode->i_sb,
+				(struct ext4_dentry_param *) data1);
+	if (data1) {
+		de->name[1] = 0;
+		memcpy(&de->name[2], data1, *(char *) data1);
+		de->file_type |= EXT4_DIRENT_LUFID;
+	}
+	de->rec_len = cpu_to_le16(EXT4_DIR_ENTRY_LEN(de));
+	dot_reclen = cpu_to_le16(de->rec_len);
 	de = ext4_next_entry(de, blocksize);
 	de->inode = cpu_to_le32(parent_ino);
 	de->name_len = 2;
+	strcpy(de->name, "..");
+	ext4_set_de_type(inode->i_sb, de, S_IFDIR);
+	data2 = ext4_dentry_get_data(inode->i_sb,
+			(struct ext4_dentry_param *) data2);
+	if (data2) {
+		de->name[2] = 0;
+		memcpy(&de->name[3], data2, *(char *) data2);
+		de->file_type |= EXT4_DIRENT_LUFID;
+	}
 	if (!dotdot_real_len)
 		de->rec_len = ext4_rec_len_to_disk(blocksize -
-					(csum_size + EXT4_DIR_REC_LEN(1)),
+					(csum_size + dot_reclen),
 					blocksize);
 	else
 		de->rec_len = ext4_rec_len_to_disk(
-				EXT4_DIR_REC_LEN(de->name_len), blocksize);
-	strcpy(de->name, "..");
-	ext4_set_de_type(inode->i_sb, de, S_IFDIR);
+				EXT4_DIR_ENTRY_LEN(de), blocksize);
 
 	return ext4_next_entry(de, blocksize);
 }
 
 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
-			     struct inode *inode)
+			     struct inode *inode,
+			     const void *data1, const void *data2)
 {
+	struct tp_block param;
 	struct buffer_head *dir_block = NULL;
 	struct ext4_dir_entry_2 *de;
 	ext4_lblk_t block = 0;
@@ -2857,7 +2947,11 @@ static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
 	if (IS_ERR(dir_block))
 		return PTR_ERR(dir_block);
 	de = (struct ext4_dir_entry_2 *)dir_block->b_data;
-	ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
+	param.inode = inode;
+	param.data1 = (void *)data1;
+	param.data2 = (void *)data2;
+	ext4_init_dot_dotdot((struct inode *)(&param), de, blocksize,
+			     csum_size, dir->i_ino, 10);
 	set_nlink(inode, 2);
 	if (csum_size)
 		ext4_initialize_dirent_tail(dir_block, blocksize);
@@ -2872,6 +2966,29 @@ out:
 	return err;
 }
 
+/* Initialize @inode as a subdirectory of @dir, and add the
+ * "." and ".." entries into the first directory block. */
+int ext4_add_dot_dotdot(handle_t *handle, struct inode *dir,
+			struct inode *inode,
+			const void *data1, const void *data2)
+{
+	int rc;
+
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if (IS_DIRSYNC(dir))
+		ext4_handle_sync(handle);
+
+	inode->i_op = &ext4_dir_inode_operations;
+	inode->i_fop = &ext4_dir_operations;
+	rc = ext4_init_new_dir(handle, dir, inode, data1, data2);
+	if (!rc)
+		rc = ext4_mark_inode_dirty(handle, inode);
+	return rc;
+}
+EXPORT_SYMBOL(ext4_add_dot_dotdot);
+
 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
 	handle_t *handle;
@@ -2898,7 +3015,7 @@ retry:
 
 	inode->i_op = &ext4_dir_inode_operations;
 	inode->i_fop = &ext4_dir_operations;
-	err = ext4_init_new_dir(handle, dir, inode);
+	err = ext4_init_new_dir(handle, dir, inode, NULL, NULL);
 	if (err)
 		goto out_clear_inode;
 	err = ext4_mark_inode_dirty(handle, inode);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d202d6d..0fcc33b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1449,7 +1449,7 @@ enum {
 	Opt_data_err_abort, Opt_data_err_ignore, Opt_test_dummy_encryption,
 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
-	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
+	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err, Opt_dirdata,
 	Opt_usrquota, Opt_grpquota, Opt_prjquota, Opt_i_version, Opt_dax,
 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_warn_on_error,
 	Opt_nowarn_on_error, Opt_mblk_io_submit,
@@ -1525,6 +1525,7 @@ static const match_table_t tokens = {
 	{Opt_nolazytime, "nolazytime"},
 	{Opt_debug_want_extra_isize, "debug_want_extra_isize=%u"},
 	{Opt_nodelalloc, "nodelalloc"},
+	{Opt_dirdata, "dirdata"},
 	{Opt_removed, "mblk_io_submit"},
 	{Opt_removed, "nomblk_io_submit"},
 	{Opt_block_validity, "block_validity"},
@@ -1748,6 +1749,7 @@ static const struct mount_opts {
 	{Opt_usrjquota, 0, MOPT_Q},
 	{Opt_grpjquota, 0, MOPT_Q},
 	{Opt_offusrjquota, 0, MOPT_Q},
+	{Opt_dirdata, EXT4_MOUNT_DIRDATA, MOPT_SET},
 	{Opt_offgrpjquota, 0, MOPT_Q},
 	{Opt_jqfmt_vfsold, QFMT_VFS_OLD, MOPT_QFMT},
 	{Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},