Index: linux-2.4.24/fs/ext3/namei.c
===================================================================
--- linux-2.4.24.orig/fs/ext3/namei.c	2004-09-23 13:10:48.181661672 +0400
+++ linux-2.4.24/fs/ext3/namei.c	2004-09-23 13:10:48.274647536 +0400
@@ -1099,6 +1099,23 @@
 	inode = NULL;
 	if (bh) {
 		unsigned long ino = le32_to_cpu(de->inode);
+		unsigned type = de->file_type;
+		__u32 *mds;
+		mds = (__u32 *)((char *) de + EXT3_DIR_REC_LEN(de->name_len));
+		if ((type & 128) && EXT3_HAS_INCOMPAT_FEATURE(dir->i_sb,
+				EXT3_FEATURE_INCOMPAT_MDSNUM) &&
+				mds[0] != EXT3_SB(dir->i_sb)->s_mdsnum) {
+			struct ext3_super_block *es;
+			es = EXT3_SB(dir->i_sb)->s_es;
+			ext3_unlock_htree(dir, lock);
+			brelse (bh);
+			dentry->d_flags |= DCACHE_CROSS_REF;
+			dentry->d_generation = mds[1];
+			dentry->d_mdsnum = mds[0];
+			dentry->d_inum = ino;
+			d_add(dentry, NULL);
+			return NULL;
+		}
 		ext3_unlock_htree(dir, lock);
 		brelse (bh);
 		inode = iget(dir->i_sb, ino);
@@ -1138,7 +1155,7 @@
 	while (count--) {
 		struct ext3_dir_entry_2 *de =
 			(struct ext3_dir_entry_2 *) (from + map->offs);
-		rec_len = EXT3_DIR_REC_LEN(de->name_len);
+		rec_len = EXT3_DIR_REC_LEN_DE(de);
 		memcpy (to, de, rec_len);
 		((struct ext3_dir_entry_2 *)to)->rec_len = cpu_to_le16(rec_len);
 		de->inode = 0;
@@ -1159,7 +1176,7 @@
 		next = (struct ext3_dir_entry_2 *) ((char *) de +
 						    le16_to_cpu(de->rec_len));
 		if (de->inode && de->name_len) {
-			rec_len = EXT3_DIR_REC_LEN(de->name_len);
+			rec_len = EXT3_DIR_REC_LEN_DE(de);
 			if (de > to)
 				memmove(to, de, rec_len);
 			to->rec_len = cpu_to_le16(rec_len);
@@ -1275,6 +1292,7 @@
 			     struct buffer_head * bh)
 {
 	struct inode	*dir = dentry->d_parent->d_inode;
+	struct super_block *sb = dir->i_sb;
 	const char	*name = dentry->d_name.name;
 	int		namelen = dentry->d_name.len;
 	unsigned long	offset = 0;
@@ -1283,6 +1301,10 @@
 	char		*top;
 	
 	reclen = EXT3_DIR_REC_LEN(namelen);
+	if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_MDSNUM)
+			&& (dentry->d_flags & DCACHE_CROSS_REF)
+			&& (dentry->d_mdsnum != EXT3_SB(sb)->s_mdsnum))
+		reclen += 8; /* we need space to store mds num */
 	if (!de) {
 		de = (struct ext3_dir_entry_2 *)bh->b_data;
 		top = bh->b_data + dir->i_sb->s_blocksize - reclen;
@@ -1296,7 +1318,7 @@
 				brelse (bh);
 				return -EEXIST;
 			}
-			nlen = EXT3_DIR_REC_LEN(de->name_len);
+			nlen = EXT3_DIR_REC_LEN_DE(de);
 			rlen = le16_to_cpu(de->rec_len);
 			if ((de->inode? rlen - nlen: rlen) >= reclen)
 				break;
@@ -1315,7 +1337,7 @@
 	}
 	
 	/* By now the buffer is marked for journaling */
-	nlen = EXT3_DIR_REC_LEN(de->name_len);
+	nlen = EXT3_DIR_REC_LEN_DE(de);
 	rlen = le16_to_cpu(de->rec_len);
 	if (de->inode) {
 		struct ext3_dir_entry_2 *de1 =
@@ -1327,8 +1349,20 @@
 	de->file_type = EXT3_FT_UNKNOWN;
 	if (inode) {
 		de->inode = cpu_to_le32(inode->i_ino);
-		ext3_set_de_type(dir->i_sb, de, inode->i_mode);
-	} else
+		ext3_set_de_type(sb, de, inode->i_mode);
+	} else if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_MDSNUM)
+			&& (dentry->d_flags & DCACHE_CROSS_REF)) {
+		if (dentry->d_mdsnum != EXT3_SB(sb)->s_mdsnum) {
+			__u32 *mds;
+			mds = (__u32 *)((char *)de + EXT3_DIR_REC_LEN(namelen));
+			mds[0] = cpu_to_le32(dentry->d_mdsnum);
+			mds[1] = cpu_to_le32(dentry->d_generation);
+			de->inode = cpu_to_le32(dentry->d_inum);
+			de->file_type = 128;
+		} else {
+			de->inode = cpu_to_le32(dentry->d_inum);
+		}
+	} else 
 		de->inode = 0;
 	de->name_len = namelen;
 	memcpy (de->name, name, namelen);
@@ -2662,6 +2696,79 @@
 }
 
 /*
+ * caller has to make sure directory is protected
+ */
+int ext3_add_dir_entry(struct dentry *dentry)
+{
+	struct inode *dir = dentry->d_parent->d_inode;
+	handle_t *handle;
+	int err;
+
+	handle = ext3_journal_start(dir, EXT3_DATA_TRANS_BLOCKS +
+					EXT3_INDEX_EXTRA_TRANS_BLOCKS);
+	if (IS_ERR(handle)) {
+		return PTR_ERR(handle);
+	}
+
+	if (IS_SYNC(dir))
+		handle->h_sync = 1;
+
+	err = ext3_add_entry(handle, dentry, NULL);
+	ext3_journal_stop(handle, dir);
+	return err;
+}
+
+/*
+ * caller has to make sure directory is protected
+ */
+int ext3_del_dir_entry(struct dentry *dentry)
+{
+	struct inode * inode;
+	struct inode * dir = dentry->d_parent->d_inode;
+	struct buffer_head * bh;
+	struct ext3_dir_entry_2 * de;
+	handle_t *handle;
+	void *lock;
+	int retval;
+
+	handle = ext3_journal_start(dir, EXT3_DELETE_TRANS_BLOCKS);
+	if (IS_ERR(handle)) {
+		return PTR_ERR(handle);
+	}
+
+	if (IS_SYNC(dir))
+		handle->h_sync = 1;
+
+	retval = -ENOENT;
+	bh = ext3_find_entry (dentry, &de, 1, &lock);
+	if (!bh)
+		goto end_unlink;
+
+	inode = dentry->d_inode;
+	if (inode)
+		DQUOT_INIT(inode);
+
+	retval = ext3_delete_entry(handle, dir, de, bh);
+	ext3_unlock_htree(dir, lock);
+	if (retval)
+		goto end_unlink;
+	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+	ext3_update_dx_flag(dir);
+	if (inode) {
+		inode->i_ctime = dir->i_ctime;
+		ext3_mark_inode_dirty(handle, inode);
+		if (S_ISDIR(inode->i_mode))
+			dir->i_nlink--;
+	}
+	ext3_mark_inode_dirty(handle, dir);
+	retval = 0;
+
+end_unlink:
+	ext3_journal_stop(handle, dir);
+	brelse (bh);
+	return retval;
+}
+/*
  * directories can handle most operations...
  */
 struct inode_operations ext3_dir_inode_operations = {
Index: linux-2.4.24/fs/ext3/dir.c
===================================================================
--- linux-2.4.24.orig/fs/ext3/dir.c	2004-09-23 13:10:45.649046688 +0400
+++ linux-2.4.24/fs/ext3/dir.c	2004-09-23 13:10:48.275647384 +0400
@@ -42,6 +42,9 @@
 
 static unsigned char get_dtype(struct super_block *sb, int filetype)
 {
+	if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_MDSNUM))
+		return DT_UNKNOWN;
+
 	if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_FILETYPE) ||
 	    (filetype >= EXT3_FT_MAX))
 		return DT_UNKNOWN;
@@ -67,8 +70,10 @@
 	else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
 		error_msg = "directory entry across blocks";
 	else if (le32_to_cpu(de->inode) >
-			le32_to_cpu(dir->i_sb->u.ext3_sb.s_es->s_inodes_count))
-		error_msg = "inode out of bounds";
+			le32_to_cpu(dir->i_sb->u.ext3_sb.s_es->s_inodes_count)) {
+		if (de->file_type != 128)
+			error_msg = "inode out of bounds";
+	}
 
 	if (error_msg != NULL)
 		ext3_error (dir->i_sb, function,
Index: linux-2.4.24/fs/ext3/ext3-exports.c
===================================================================
--- linux-2.4.24.orig/fs/ext3/ext3-exports.c	2004-09-23 13:10:46.365937704 +0400
+++ linux-2.4.24/fs/ext3/ext3-exports.c	2004-09-23 13:10:48.275647384 +0400
@@ -26,3 +26,10 @@
 EXPORT_SYMBOL(ext3_decode_error);
 EXPORT_SYMBOL(__ext3_std_error);
 
+int ext3_add_dir_entry (struct dentry *dentry);
+EXPORT_SYMBOL(ext3_add_dir_entry);
+int ext3_del_dir_entry(struct dentry *dentry);
+EXPORT_SYMBOL(ext3_del_dir_entry);
+
+
+
Index: linux-2.4.24/include/linux/ext3_fs.h
===================================================================
--- linux-2.4.24.orig/include/linux/ext3_fs.h	2004-09-23 13:10:48.188660608 +0400
+++ linux-2.4.24/include/linux/ext3_fs.h	2004-09-23 13:17:40.703948752 +0400
@@ -446,7 +446,8 @@
 	__u8	s_def_hash_version;	/* Default hash version to use */
 	__u8	s_reserved_char_pad;
 	__u16	s_reserved_word_pad;
-	__u32	s_reserved[192];	/* Padding to the end of the block */
+	__u32	s_mdsnum;
+	__u32	s_reserved[191];	/* Padding to the end of the block */
 };
 
 #ifdef __KERNEL__
@@ -519,11 +520,13 @@
 #define EXT3_FEATURE_INCOMPAT_FILETYPE		0x0002
 #define EXT3_FEATURE_INCOMPAT_RECOVER		0x0004 /* Needs recovery */
 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008 /* Journal device */
+#define EXT3_FEATURE_INCOMPAT_MDSNUM		0x0020 /* direntry has mdsnum */
 #define EXT3_FEATURE_INCOMPAT_EXTENTS		0x0040 /* extents support */
 
 #define EXT3_FEATURE_COMPAT_SUPP	EXT2_FEATURE_COMPAT_EXT_ATTR
 #define EXT3_FEATURE_INCOMPAT_SUPP	(EXT3_FEATURE_INCOMPAT_FILETYPE| \
 					 EXT3_FEATURE_INCOMPAT_RECOVER| \
+					 EXT3_FEATURE_INCOMPAT_MDSNUM| \
 					 EXT3_FEATURE_INCOMPAT_EXTENTS)
 #define EXT3_FEATURE_RO_COMPAT_SUPP	(EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 					 EXT3_FEATURE_RO_COMPAT_LARGE_FILE| \
@@ -585,6 +588,9 @@
 #define EXT3_DIR_ROUND			(EXT3_DIR_PAD - 1)
 #define EXT3_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT3_DIR_ROUND) & \
 					 ~EXT3_DIR_ROUND)
+#define EXT3_DIR_REC_LEN_DE(de)		(EXT3_DIR_REC_LEN((de)->name_len) + \
+					(((de)->file_type & 128) ? 8 : 0))
+
 /*
  * Hash Tree Directory indexing
  * (c) Daniel Phillips, 2001
Index: linux-2.4.24/include/linux/ext3_fs_sb.h
===================================================================
--- linux-2.4.24.orig/include/linux/ext3_fs_sb.h	2004-09-23 13:10:46.069982696 +0400
+++ linux-2.4.24/include/linux/ext3_fs_sb.h	2004-09-23 13:11:21.026668472 +0400
@@ -86,6 +86,7 @@
 	wait_queue_head_t s_delete_thread_queue;
 	wait_queue_head_t s_delete_waiter_queue;
 #endif
+	u32 s_mdsnum;
 };
 
 #endif	/* _LINUX_EXT3_FS_SB */
Index: linux-2.4.24/include/linux/dcache.h
===================================================================
--- linux-2.4.24.orig/include/linux/dcache.h	2004-09-23 13:10:46.153969928 +0400
+++ linux-2.4.24/include/linux/dcache.h	2004-09-23 13:11:06.451884176 +0400
@@ -120,6 +120,9 @@
 	atomic_t d_count;
 	unsigned int d_flags;
 	struct inode  * d_inode;	/* Where the name belongs to - NULL is negative */
+	unsigned d_inum;		/* for cross-fs references (Lustre) */
+	unsigned d_mdsnum;		/* for cross-fs references (Lustre) */
+	unsigned d_generation;		/* for cross-fs references (Lustre) */
 	struct dentry * d_parent;	/* parent directory */
 	struct list_head d_hash;	/* lookup hash list */
 	struct list_head d_lru;		/* d_count = 0 LRU list */
@@ -193,6 +196,7 @@
 					 */
 #define DCACHE_REFERENCED	0x0008  /* Recently used, don't discard. */
 #define DCACHE_LUSTRE_INVALID	0x0010  /* Lustre invalidated */
+#define DCACHE_CROSS_REF	0x0020	/* entry points to inode on another MDS */
 
 extern spinlock_t dcache_lock;