Index: linux-stage/fs/ext4/ialloc.c
===================================================================
--- linux-stage.orig/fs/ext4/ialloc.c
+++ linux-stage/fs/ext4/ialloc.c
@@ -700,12 +700,15 @@ struct inode *ext4_new_inode(handle_t *h
 		return ERR_PTR(-EPERM);
 
 	sb = dir->i_sb;
+	sbi = EXT4_SB(sb);
+	if (sbi->s_max_dir_size > 0 && i_size_read(dir) >= sbi->s_max_dir_size)
+		return ERR_PTR(-EFBIG);
+
 	inode = new_inode(sb);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 	ei = EXT4_I(inode);
 
-	sbi = EXT4_SB(sb);
 	es = sbi->s_es;
 
 	if (goal) {
Index: linux-stage/fs/ext4/super.c
===================================================================
--- linux-stage.orig/fs/ext4/super.c
+++ linux-stage/fs/ext4/super.c
@@ -41,6 +41,7 @@
 #include <asm/uaccess.h>
 #include <linux/kthread.h>
 #include <linux/utsname.h>
+#include <linux/proc_fs.h>
 
 #include "ext4.h"
 #include "ext4_jbd2.h"
@@ -71,6 +72,8 @@ static void ext4_write_super(struct supe
 static void ext4_write_super_lockfs(struct super_block *sb);
 
 
+struct proc_dir_entry *proc_root_ext4;
+
 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
 			       struct ext4_group_desc *bg)
 {
@@ -564,6 +567,7 @@ static void ext4_put_super(struct super_
 	}
 	if (sbi->s_proc) {
 		remove_proc_entry("inode_readahead_blks", sbi->s_proc);
+		remove_proc_entry(EXT4_MAX_DIR_SIZE_NAME, sbi->s_proc);
 		remove_proc_entry(sb->s_id, ext4_proc_root);
 	}
 
@@ -602,6 +606,7 @@ static void ext4_put_super(struct super_
 	}
 	if (sbi->s_mmp_tsk)
 		kthread_stop(sbi->s_mmp_tsk);
+
 	sb->s_fs_info = NULL;
 	kfree(sbi);
 	return;
@@ -2287,6 +2292,46 @@ static unsigned long ext4_get_stripe_siz
 	return 0;
 }
 
+static int ext4_max_dir_size_read(char *page, char **start, off_t off,
+                                  int count, int *eof, void *data)
+{
+	struct ext4_sb_info *sbi = data;
+	int len;
+
+	*eof = 1;
+	if (off != 0)
+		return 0;
+
+	len = sprintf(page, "%lu\n", sbi->s_max_dir_size);
+	*start = page;
+	return len;
+}
+
+static int ext4_max_dir_size_write(struct file *file, const char *buffer,
+                                   unsigned long count, void *data)
+{
+	struct ext4_sb_info *sbi = data;
+	char str[32];
+	unsigned long value;
+	char *end;
+
+	if (count >= sizeof(str)) {
+		printk(KERN_ERR "EXT4-fs: %s string too long, max %u bytes\n",
+		       EXT4_MAX_DIR_SIZE_NAME, (int)sizeof(str));
+		return -EOVERFLOW;
+	}
+
+	if (copy_from_user(str, buffer, count))
+		return -EFAULT;
+
+	value = simple_strtol(str, &end, 0);
+	if (value < 0)
+		return -ERANGE;
+
+	sbi->s_max_dir_size = value;
+	return count;
+}
+
 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 				__releases(kernel_lock)
 				__acquires(kernel_lock)
@@ -2311,6 +2356,7 @@ static int ext4_fill_super(struct super_
 	int needs_recovery, has_huge_files;
 	int features;
 	__u64 blocks_count;
+	struct proc_dir_entry *proc;
 	int err;
 
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
@@ -2880,6 +2926,22 @@ static int ext4_fill_super(struct super_
 	       test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA ? "ordered":
 	       "writeback");
 
+	sbi->s_max_dir_size = EXT4_DEFAULT_MAX_DIR_SIZE;
+	proc = create_proc_entry(EXT4_MAX_DIR_SIZE_NAME,
+				 S_IFREG | S_IRUGO | S_IWUSR, sbi->s_proc);
+	if (proc == NULL) {
+		printk(KERN_ERR "EXT4-fs: unable to create %s\n",
+		       EXT4_MAX_DIR_SIZE_NAME);
+		remove_proc_entry(EXT4_MAX_DIR_SIZE_NAME, sbi->s_proc);
+		remove_proc_entry(sbi->s_proc->name, proc_root_ext4);
+		sbi->s_proc = NULL;
+		ret = -ENOMEM;
+		goto failed_mount4;
+	}
+	proc->data = sbi;
+	proc->read_proc = ext4_max_dir_size_read;
+	proc->write_proc = ext4_max_dir_size_write;
+
 	lock_kernel();
 	return 0;
 
@@ -3253,7 +3315,6 @@ static void ext4_commit_super(struct sup
 	}
 }
 
-
 /*
  * Have we just finished recovery?  If so, and if we are mounting (or
  * remounting) the filesystem readonly, then we will end up with a
Index: linux-stage/fs/ext4/ext4_sb.h
===================================================================
--- linux-stage.orig/fs/ext4/ext4_sb.h
+++ linux-stage/fs/ext4/ext4_sb.h
@@ -118,6 +118,7 @@ struct ext4_sb_info {
 	/* where last allocation was done - for stream allocation */
 	unsigned long s_mb_last_group;
 	unsigned long s_mb_last_start;
+	unsigned long s_max_dir_size;
 
 	/* history to debug policy */
 	struct ext4_mb_history *s_mb_history;
Index: linux-stage/fs/ext4/ext4.h
===================================================================
--- linux-stage.orig/fs/ext4/ext4.h
+++ linux-stage/fs/ext4/ext4.h
@@ -1017,6 +1017,14 @@ struct mmp_struct {
  */
 #define EXT4_MMP_MIN_CHECK_INTERVAL	5
 
+extern struct proc_dir_entry *proc_root_ext4;
+
+/*
+ * max directory size tunable
+ */
+#define EXT4_DEFAULT_MAX_DIR_SIZE	0
+#define EXT4_MAX_DIR_SIZE_NAME		"max_dir_size"
+
 /*
  * Function prototypes
  */
Index: linux-stage/fs/ext4/mballoc.c
===================================================================
--- linux-stage.orig/fs/ext4/mballoc.c
+++ linux-stage/fs/ext4/mballoc.c
@@ -2943,6 +2943,7 @@ err_out:
 	remove_proc_entry(EXT4_MB_MIN_TO_SCAN_NAME, sbi->s_proc);
 	remove_proc_entry(EXT4_MB_MAX_TO_SCAN_NAME, sbi->s_proc);
 	remove_proc_entry(EXT4_MB_STATS_NAME, sbi->s_proc);
+	remove_proc_entry(EXT4_MAX_DIR_SIZE_NAME, sbi->s_proc);
 	return -ENOMEM;
 #else
 	return 0;
@@ -2963,6 +2964,7 @@ static int ext4_mb_destroy_per_dev_proc(
 	remove_proc_entry(EXT4_MB_MIN_TO_SCAN_NAME, sbi->s_proc);
 	remove_proc_entry(EXT4_MB_MAX_TO_SCAN_NAME, sbi->s_proc);
 	remove_proc_entry(EXT4_MB_STATS_NAME, sbi->s_proc);
+	remove_proc_entry(EXT4_MAX_DIR_SIZE_NAME, sbi->s_proc);
 #endif
 	return 0;
 }