f2fs: avoid infinite loop on cp_error

If cp_error is set, we should avoid all the infinite loop.
In f2fs_sync_file, there is a hole, and this patch fixes that.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 5df3367..710adc9 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -247,6 +247,10 @@
 sync_nodes:
 	sync_node_pages(sbi, ino, &wbc);
 
+	/* if cp_error was enabled, we should avoid infinite loop */
+	if (unlikely(f2fs_cp_error(sbi)))
+		goto out;
+
 	if (need_inode_block_update(sbi, ino)) {
 		mark_inode_dirty_sync(inode);
 		f2fs_write_inode(inode, NULL);