diff -rupN linux-2.6.27.21-0.1_1//fs/ext4/ext4_i.h linux-2.6.27.21-0.1_2//fs/ext4/ext4_i.h
--- linux-2.6.27.21-0.1_1//fs/ext4/ext4.h	2009-08-24 13:00:59.000000000 +0530
+++ linux-2.6.27.21-0.1_2//fs/ext4/ext4.h	2009-08-24 13:01:25.000000000 +0530
@@ -16,6 +16,7 @@
 #include <linux/blkdev.h>
 #include <linux/magic.h>
 #include <linux/jbd2.h>
+#include <linux/dynlocks.h>
 #include <linux/rwsem.h>
 #include <linux/rbtree.h>
 #include <linux/seqlock.h>
@@ -56,7 +57,9 @@ struct ext4_inode_info {
 	__u32	i_flags;
 	ext4_fsblk_t	i_file_acl;
 	__u32	i_dtime;
-
+	/* following fields for parallel directory operations -bzzz */
+	struct dynlock   i_htree_lock;
+	struct semaphore i_append_sem;
 	/*
 	 * i_block_group is the number of the block group which contains
 	 * this file's inode.  Constant across the lifetime of the inode,
diff -rupN linux-2.6.27.21-0.1_1//fs/ext4/namei.c linux-2.6.27.21-0.1_2//fs/ext4/namei.c
--- linux-2.6.27.21-0.1_1//fs/ext4/namei.c	2009-08-24 13:00:59.000000000 +0530
+++ linux-2.6.27.21-0.1_2//fs/ext4/namei.c	2009-08-24 13:03:45.000000000 +0530
@@ -55,6 +55,11 @@ static struct buffer_head *ext4_append(h
 					ext4_lblk_t *block, int *err)
 {
 	struct buffer_head *bh;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	/* with parallel dir operations all appends
+	* have to be serialized -bzzz */
+	down(&ei->i_append_sem);
 
 	*block = inode->i_size >> inode->i_sb->s_blocksize_bits;
 
@@ -67,7 +72,9 @@ static struct buffer_head *ext4_append(h
 			brelse(bh);
 			bh = NULL;
 		}
+		ei->i_disksize = inode->i_size;
 	}
+	up(&ei->i_append_sem);
 	return bh;
 }
 
diff -rupN linux-2.6.27.21-0.1_1//fs/ext4/super.c linux-2.6.27.21-0.1_2//fs/ext4/super.c
--- linux-2.6.27.21-0.1_1//fs/ext4/super.c	2009-08-24 13:00:59.000000000 +0530
+++ linux-2.6.27.21-0.1_2//fs/ext4/super.c	2009-08-24 13:01:25.000000000 +0530
@@ -635,6 +635,8 @@ static struct inode *ext4_alloc_inode(st
 #endif
 	ei->vfs_inode.i_version = 1;
 	ei->vfs_inode.i_data.writeback_index = 0;
+	dynlock_init(&ei->i_htree_lock);
+	sema_init(&ei->i_append_sem, 1);
 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
 	INIT_LIST_HEAD(&ei->i_prealloc_list);
 	spin_lock_init(&ei->i_prealloc_lock);