linux-kernel - Re: [PATCH v2 8/8] cifs: update the ctime on a partial page write

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Date:   Mon, 12 Jun 2023 09:41:38 -0400
From:   Tom Talpey <tom@...pey.com>
To:     Jeff Layton <jlayton@...nel.org>,
        Christian Brauner <brauner@...nel.org>,
        Al Viro <viro@...iv.linux.org.uk>,
        Brad Warrum <bwarrum@...ux.ibm.com>,
        Ritu Agarwal <rituagar@...ux.ibm.com>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Ian Kent <raven@...maw.net>,
        "Tigran A. Aivazian" <aivazian.tigran@...il.com>,
        Jeremy Kerr <jk@...abs.org>, Ard Biesheuvel <ardb@...nel.org>,
        Namjae Jeon <linkinjeon@...nel.org>,
        Sungjong Seo <sj1557.seo@...sung.com>,
        Steve French <sfrench@...ba.org>,
        Paulo Alcantara <pc@...guebit.com>,
        Ronnie Sahlberg <lsahlber@...hat.com>,
        Shyam Prasad N <sprasad@...rosoft.com>,
        John Johansen <john.johansen@...onical.com>,
        Paul Moore <paul@...l-moore.com>,
        James Morris <jmorris@...ei.org>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        Ruihan Li <lrh2000@....edu.cn>,
        Sebastian Reichel <sebastian.reichel@...labora.com>,
        Alan Stern <stern@...land.harvard.edu>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        autofs@...r.kernel.org, linux-efi@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-cifs@...r.kernel.org,
        samba-technical@...ts.samba.org, apparmor@...ts.ubuntu.com,
        linux-security-module@...r.kernel.org
Subject: Re: [PATCH v2 8/8] cifs: update the ctime on a partial page write

On 6/12/2023 6:45 AM, Jeff Layton wrote:
> POSIX says:
> 
>      "Upon successful completion, where nbyte is greater than 0, write()
>       shall mark for update the last data modification and last file status
>       change timestamps of the file..."
> 
> Add the missing ctime update.
> 
> Signed-off-by: Jeff Layton <jlayton@...nel.org>
> ---
>   fs/smb/client/file.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
> index df88b8c04d03..a00038a326cf 100644
> --- a/fs/smb/client/file.c
> +++ b/fs/smb/client/file.c
> @@ -2596,7 +2596,7 @@ static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
>   					   write_data, to - from, &offset);
>   		cifsFileInfo_put(open_file);
>   		/* Does mm or vfs already set times? */
> -		inode->i_atime = inode->i_mtime = current_time(inode);
> +		inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);

Question. It appears that roughly half the filesystems in this series
don't touch the i_atime in this case. And the other half do. Which is
correct? Did they incorrectly set i_atime instead of i_ctime?

Tom.

>   		if ((bytes_written > 0) && (offset))
>   			rc = 0;
>   		else if (bytes_written < 0)