f2fs: call f2fs_unlock_op after error was handled

This patch relocates f2fs_unlock_op in every directory operations to be called
after any error was processed.
Otherwise, the checkpoint can be entered with valid node ids without its
dentry when -ENOSPC is occurred.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 94cfdc4..a397f7a 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1194,6 +1194,7 @@
 void update_inode_page(struct inode *);
 int f2fs_write_inode(struct inode *, struct writeback_control *);
 void f2fs_evict_inode(struct inode *);
+void handle_failed_inode(struct inode *);
 
 /*
  * namei.c