Re: [PATCH v7 10/15] fs: Add async write file modification handling.

[Jan Kara <jack@suse.cz>]

On Wed 01-06-22 14:01:36, Stefan Roesch wrote:
> This adds a file_modified_async() function to return -EAGAIN if the
> request either requires to remove privileges or needs to update the file
> modification time. This is required for async buffered writes, so the
> request gets handled in the io worker of io-uring.
> 
> Signed-off-by: Stefan Roesch <shr@fb.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Looks good to me. Feel free to add:

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

								Honza

> ---
>  fs/inode.c         | 43 +++++++++++++++++++++++++++++++++++++++++--
>  include/linux/fs.h |  1 +
>  2 files changed, 42 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/inode.c b/fs/inode.c
> index c44573a32c6a..4503bed063e7 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2116,17 +2116,21 @@ int file_update_time(struct file *file)
>  EXPORT_SYMBOL(file_update_time);
>  
>  /**
> - * file_modified - handle mandated vfs changes when modifying a file
> + * file_modified_flags - handle mandated vfs changes when modifying a file
>   * @file: file that was modified
> + * @flags: kiocb flags
>   *
>   * When file has been modified ensure that special
>   * file privileges are removed and time settings are updated.
>   *
> + * If IOCB_NOWAIT is set, special file privileges will not be removed and
> + * time settings will not be updated. It will return -EAGAIN.
> + *
>   * Context: Caller must hold the file's inode lock.
>   *
>   * Return: 0 on success, negative errno on failure.
>   */
> -int file_modified(struct file *file)
> +static int file_modified_flags(struct file *file, int flags)
>  {
>  	int ret;
>  	struct inode *inode = file_inode(file);
> @@ -2146,11 +2150,46 @@ int file_modified(struct file *file)
>  	ret = inode_needs_update_time(inode, &now);
>  	if (ret <= 0)
>  		return ret;
> +	if (flags & IOCB_NOWAIT)
> +		return -EAGAIN;
>  
>  	return __file_update_time(file, &now, ret);
>  }
> +
> +/**
> + * file_modified - handle mandated vfs changes when modifying a file
> + * @file: file that was modified
> + *
> + * When file has been modified ensure that special
> + * file privileges are removed and time settings are updated.
> + *
> + * Context: Caller must hold the file's inode lock.
> + *
> + * Return: 0 on success, negative errno on failure.
> + */
> +int file_modified(struct file *file)
> +{
> +	return file_modified_flags(file, 0);
> +}
>  EXPORT_SYMBOL(file_modified);
>  
> +/**
> + * kiocb_modified - handle mandated vfs changes when modifying a file
> + * @iocb: iocb that was modified
> + *
> + * When file has been modified ensure that special
> + * file privileges are removed and time settings are updated.
> + *
> + * Context: Caller must hold the file's inode lock.
> + *
> + * Return: 0 on success, negative errno on failure.
> + */
> +int kiocb_modified(struct kiocb *iocb)
> +{
> +	return file_modified_flags(iocb->ki_filp, iocb->ki_flags);
> +}
> +EXPORT_SYMBOL_GPL(kiocb_modified);
> +
>  int inode_needs_sync(struct inode *inode)
>  {
>  	if (IS_SYNC(inode))
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index bdf1ce48a458..553e57ec3efa 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2392,6 +2392,7 @@ static inline void file_accessed(struct file *file)
>  }
>  
>  extern int file_modified(struct file *file);
> +int kiocb_modified(struct kiocb *iocb);
>  
>  int sync_inode_metadata(struct inode *inode, int wait);
>  
> -- 
> 2.30.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR