Revert "vfs: fix freeze protection in mnt_want_write_file() for overlayfs"

This reverts commit 4f4374a which was
commit a6795a5 upstream.

Turns out this causes problems and was to fix a patch only in the 4.19
and newer tree.

Reported-by: Amir Goldstein <amir73il@gmail.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: gregkh

fs/namespace.c

@@ -446,10 +446,10 @@ int mnt_want_write_file_path(struct file *file)
 {
 	int ret;
 
-	sb_start_write(file_inode(file)->i_sb);
+	sb_start_write(file->f_path.mnt->mnt_sb);
 	ret = __mnt_want_write_file(file);
 	if (ret)
-		sb_end_write(file_inode(file)->i_sb);
+		sb_end_write(file->f_path.mnt->mnt_sb);
 	return ret;
 }
 
@@ -540,8 +540,7 @@ void __mnt_drop_write_file(struct file *file)
 
 void mnt_drop_write_file_path(struct file *file)
 {
-	__mnt_drop_write_file(file);
-	sb_end_write(file_inode(file)->i_sb);
+	mnt_drop_write(file->f_path.mnt);
 }
 
 void mnt_drop_write_file(struct file *file)