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Date: Sat, 13 Jan 2024 17:02:13 +0000
From: Matthew Wilcox <willy@infradead.org>
To: Steve French <smfrench@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	Salvatore Bonaccorso <carnil@debian.org>,
	Paulo Alcantara <pc@manguebit.com>,
	Shyam Prasad N <nspmangalore@gmail.com>,
	Rohith Surabattula <rohiths.msft@gmail.com>,
	Jeff Layton <jlayton@kernel.org>,
	Steve French <stfrench@microsoft.com>,
	"Jitindar Singh, Suraj" <surajjs@amazon.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"stable-commits@vger.kernel.org" <stable-commits@vger.kernel.org>,
	stable@vger.kernel.org, linux-cifs@vger.kernel.org,
	Linux regressions mailing list <regressions@lists.linux.dev>
Subject: Re: [Regression 6.1.y] From "cifs: Fix flushing, invalidation and
 file size with copy_file_range()"
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On Fri, Jan 12, 2024 at 11:20:53PM -0600, Steve French wrote:
> Here is a patch similar to what David suggested.  Seems

Similar to, but worse.

> +++ b/fs/smb/client/cifsfs.c
> @@ -1240,7 +1240,7 @@ static int cifs_flush_folio(struct inode *inode, loff_t pos, loff_t *_fstart, lo
>  	int rc = 0;
>  
>  	folio = filemap_get_folio(inode->i_mapping, index);
> -	if (IS_ERR(folio))
> +	if ((!folio) || (IS_ERR(folio)))
>  		return 0;

filemap_get_folio() cannot return an err_ptr in 6.1, so this should
simply be:

-	if (IS_ERR(folio))
+	if (!folio)