linux-kernel - Re: [PATCH 01/14] fs: refactor file timestamp update logic

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Message-ID: <muv2257pdsdqq3mfqay72rgxgiklnbmcj545tcq5tx3ap4hhue@rccqkibodbv3>
Date: Mon, 24 Nov 2025 12:51:48 +0100
From: Jan Kara <jack@...e.cz>
To: Christoph Hellwig <hch@....de>
Cc: Christian Brauner <brauner@...nel.org>, 
	Al Viro <viro@...iv.linux.org.uk>, David Sterba <dsterba@...e.com>, Jan Kara <jack@...e.cz>, 
	Mike Marshall <hubcap@...ibond.com>, Martin Brandenburg <martin@...ibond.com>, 
	Carlos Maiolino <cem@...nel.org>, Stefan Roesch <shr@...com>, Jeff Layton <jlayton@...nel.org>, 
	linux-kernel@...r.kernel.org, linux-btrfs@...r.kernel.org, gfs2@...ts.linux.dev, 
	io-uring@...r.kernel.org, devel@...ts.orangefs.org, linux-unionfs@...r.kernel.org, 
	linux-mtd@...ts.infradead.org, linux-xfs@...r.kernel.org, linux-nfs@...r.kernel.org
Subject: Re: [PATCH 01/14] fs: refactor file timestamp update logic

On Fri 14-11-25 07:26:04, Christoph Hellwig wrote:
> Currently the two high-level APIs use two helper functions to implement
> almost all of the logic.  Refactor the two helpers and the common logic
> into a new file_update_time_flags routine that gets the iocb flags or
> 0 in case of file_update_time passed so that the entire logic is
> contained in a single function and can be easily understood and modified.
> 
> Signed-off-by: Christoph Hellwig <hch@....de>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/inode.c | 54 +++++++++++++++++-------------------------------------
>  1 file changed, 17 insertions(+), 37 deletions(-)
> 
> diff --git a/fs/inode.c b/fs/inode.c
> index ec9339024ac3..4884ffa931e7 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2310,10 +2310,12 @@ struct timespec64 current_time(struct inode *inode)
>  }
>  EXPORT_SYMBOL(current_time);
>  
> -static int inode_needs_update_time(struct inode *inode)
> +static int file_update_time_flags(struct file *file, unsigned int flags)
>  {
> +	struct inode *inode = file_inode(file);
>  	struct timespec64 now, ts;
> -	int sync_it = 0;
> +	int sync_mode = 0;
> +	int ret = 0;
>  
>  	/* First try to exhaust all avenues to not sync */
>  	if (IS_NOCMTIME(inode))
> @@ -2323,29 +2325,23 @@ static int inode_needs_update_time(struct inode *inode)
>  
>  	ts = inode_get_mtime(inode);
>  	if (!timespec64_equal(&ts, &now))
> -		sync_it |= S_MTIME;
> -
> +		sync_mode |= S_MTIME;
>  	ts = inode_get_ctime(inode);
>  	if (!timespec64_equal(&ts, &now))
> -		sync_it |= S_CTIME;
> -
> +		sync_mode |= S_CTIME;
>  	if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode))
> -		sync_it |= S_VERSION;
> +		sync_mode |= S_VERSION;
>  
> -	return sync_it;
> -}
> -
> -static int __file_update_time(struct file *file, int sync_mode)
> -{
> -	int ret = 0;
> -	struct inode *inode = file_inode(file);
> +	if (!sync_mode)
> +		return 0;
>  
> -	/* try to update time settings */
> -	if (!mnt_get_write_access_file(file)) {
> -		ret = inode_update_time(inode, sync_mode);
> -		mnt_put_write_access_file(file);
> -	}
> +	if (flags & IOCB_NOWAIT)
> +		return -EAGAIN;
>  
> +	if (mnt_get_write_access_file(file))
> +		return 0;
> +	ret = inode_update_time(inode, sync_mode);
> +	mnt_put_write_access_file(file);
>  	return ret;
>  }
>  
> @@ -2365,14 +2361,7 @@ static int __file_update_time(struct file *file, int sync_mode)
>   */
>  int file_update_time(struct file *file)
>  {
> -	int ret;
> -	struct inode *inode = file_inode(file);
> -
> -	ret = inode_needs_update_time(inode);
> -	if (ret <= 0)
> -		return ret;
> -
> -	return __file_update_time(file, ret);
> +	return file_update_time_flags(file, 0);
>  }
>  EXPORT_SYMBOL(file_update_time);
>  
> @@ -2394,7 +2383,6 @@ EXPORT_SYMBOL(file_update_time);
>  static int file_modified_flags(struct file *file, int flags)
>  {
>  	int ret;
> -	struct inode *inode = file_inode(file);
>  
>  	/*
>  	 * Clear the security bits if the process is not being run by root.
> @@ -2403,17 +2391,9 @@ static int file_modified_flags(struct file *file, int flags)
>  	ret = file_remove_privs_flags(file, flags);
>  	if (ret)
>  		return ret;
> -
>  	if (unlikely(file->f_mode & FMODE_NOCMTIME))
>  		return 0;
> -
> -	ret = inode_needs_update_time(inode);
> -	if (ret <= 0)
> -		return ret;
> -	if (flags & IOCB_NOWAIT)
> -		return -EAGAIN;
> -
> -	return __file_update_time(file, ret);
> +	return file_update_time_flags(file, flags);
>  }
>  
>  /**
> -- 
> 2.47.3
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR