f2fs: Add f2fs_balance_fs for direct IO

[Huang Ying <ying.huang@intel.com>]

Otherwise, if a large amount of direct IO writes were done, the
segment allocation may be failed because no enough segments are gced.

Signed-off-by: Huang, Ying <ying.huang@intel.com>
---
 fs/f2fs/data.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1038,6 +1038,7 @@ static ssize_t f2fs_direct_IO(int rw, st
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 
 	/* Let buffer I/O handle the inline data case. */
 	if (f2fs_has_inline_data(inode))
@@ -1046,8 +1047,11 @@ static ssize_t f2fs_direct_IO(int rw, st
 	if (check_direct_IO(inode, rw, iter, offset))
 		return 0;
 
+	if (rw == WRITE)
+		f2fs_balance_fs(sbi);
+
 	/* clear fsync mark to recover these blocks */
-	fsync_mark_clear(F2FS_SB(inode->i_sb), inode->i_ino);
+	fsync_mark_clear(sbi, inode->i_ino);
 
 	return blockdev_direct_IO(rw, iocb, inode, iter, offset,
 				  get_data_block);