Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/ext4/super.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff -puN fs/ext4/super.c~ext4-mm-enable-delalloc-by-default fs/ext4/super.c
--- a/fs/ext4/super.c~ext4-mm-enable-delalloc-by-default
+++ a/fs/ext4/super.c
@@ -888,7 +888,7 @@ enum {
 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
 	Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
 	Opt_grpquota, Opt_extents, Opt_noextents, Opt_i_version,
-	Opt_mballoc, Opt_nomballoc, Opt_stripe, Opt_delalloc,
+	Opt_mballoc, Opt_nomballoc, Opt_stripe, Opt_delalloc, Opt_nodelalloc,
 };
 
 static match_table_t tokens = {
@@ -948,6 +948,7 @@ static match_table_t tokens = {
 	{Opt_stripe, "stripe=%u"},
 	{Opt_resize, "resize"},
 	{Opt_delalloc, "delalloc"},
+	{Opt_nodelalloc, "nodelalloc"},
 	{Opt_err, NULL},
 };
 
@@ -1296,6 +1297,9 @@ clear_qf_name:
 			set_opt(sbi->s_mount_opt, I_VERSION);
 			sb->s_flags |= MS_I_VERSION;
 			break;
+		case Opt_nodelalloc:
+			clear_opt(sbi->s_mount_opt, DELALLOC);
+			break;
 		case Opt_mballoc:
 			set_opt(sbi->s_mount_opt, MBALLOC);
 			break;
@@ -1959,6 +1963,14 @@ static int ext4_fill_super (struct super
 	 */
 	set_opt(sbi->s_mount_opt, MBALLOC);
 
+	/*
+	 * enable delayed allocation by default
+	 * Use -o nodelalloc to turn it off
+	 */
+	set_opt(sbi->s_mount_opt, DELALLOC);
+	set_opt(sbi->s_mount_opt, WRITEBACK_DATA);
+
+
 	if (!parse_options ((char *) data, sb, &journal_inum, &journal_devnum,
 			    NULL, 0))
 		goto failed_mount;
_