ext4: remove redundant code in ext4_alloc_inode()

inode_init_always() will initialize inode->i_data.writeback_index
anyway, no need to do this in ext4_alloc_inode().
Signed-off-by: NGuo Chao <yan@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: NLukas Czerner <lczerner@redhat.com>

fs/ext4/super.c

@@ -939,7 +939,6 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
 		return NULL;
 
 	ei->vfs_inode.i_version = 1;
-	ei->vfs_inode.i_data.writeback_index = 0;
 	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);