f2fs: recover date requested by fdatasync

In order to support SQLite that uses fdatasync instead of fsync, we should
guarantee the data requested by fdatasync can be recovered after sudden-power-
off.

So, let's remove the fdatasync condition in f2fs_sync_file.
Otherwise, we can restore the data after sudden-power-off due to nonexistence
of any fsync mark'ed node blocks.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/file.c

@@ -147,9 +147,10 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 
 	mutex_lock(&inode->i_mutex);
 
-	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
-		goto out;
-
+	/*
+	 * Both of fdatasync() and fsync() are able to be recovered from
+	 * sudden-power-off.
+	 */
 	if (!S_ISREG(inode->i_mode) || inode->i_nlink != 1)
 		need_cp = true;
 	else if (file_wrong_pino(inode))