[PATCH 4/5] f2fs: support data flush in ioctl

[Chao Yu <chao2.yu@samsung.com>]

Sometimes user want to sync all data belong to superblock into storage
for persistence, 'syncfs' syscall is one option, still f2fs supports
similar one through ioctl, difference is that sb releted kworker is
online for writebacking concurrently.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
---
 fs/f2fs/file.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index a60d088..91997a5 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1621,6 +1621,7 @@ static int f2fs_ioc_write_checkpoint(struct file *filp, unsigned long arg)
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct cp_control cpc;
 	int err;
+	int flush_data;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
@@ -1628,6 +1629,15 @@ static int f2fs_ioc_write_checkpoint(struct file *filp, unsigned long arg)
 	if (f2fs_readonly(sbi->sb))
 		return -EROFS;
 
+	if (get_user(flush_data, (__u32 __user *)arg))
+		return -EFAULT;
+
+	if (flush_data) {
+		err = sync_dirty_inodes(sbi, FILE_INODE);
+		if (err)
+			return err;
+	}
+
 	cpc.reason = __get_cp_reason(sbi);
 
 	mutex_lock(&sbi->gc_mutex);
-- 
2.6.3