Re: [PATCH 2/8] iomap: add a filesystem hook for direct I/O bio submission

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, Dec 13, 2019 at 01:57:44PM -0600, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@suse.com>
> 
> This helps filesystems to perform tasks on the bio while submitting for
> I/O. This could be post-write operations such as data CRC or data
> replication for fs-handled RAID.
> 
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
> Reviewed-by: Nikolay Borisov <nborisov@suse.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/iomap/direct-io.c  | 14 +++++++++-----
>  include/linux/iomap.h |  2 ++
>  2 files changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> index 23837926c0c5..1a3bf3bd86fb 100644
> --- a/fs/iomap/direct-io.c
> +++ b/fs/iomap/direct-io.c
> @@ -59,7 +59,7 @@ int iomap_dio_iopoll(struct kiocb *kiocb, bool spin)
>  EXPORT_SYMBOL_GPL(iomap_dio_iopoll);
>  
>  static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap,
> -		struct bio *bio)
> +		struct bio *bio, loff_t pos)
>  {
>  	atomic_inc(&dio->ref);
>  
> @@ -67,7 +67,11 @@ static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap,
>  		bio_set_polled(bio, dio->iocb);
>  
>  	dio->submit.last_queue = bdev_get_queue(iomap->bdev);
> -	dio->submit.cookie = submit_bio(bio);
> +	if (dio->dops && dio->dops->submit_io)
> +		dio->submit.cookie = dio->dops->submit_io(bio,
> +				dio->iocb->ki_filp, pos);
> +	else
> +		dio->submit.cookie = submit_bio(bio);
>  }
>  
>  static ssize_t iomap_dio_complete(struct iomap_dio *dio)
> @@ -191,7 +195,7 @@ iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
>  	get_page(page);
>  	__bio_add_page(bio, page, len, 0);
>  	bio_set_op_attrs(bio, REQ_OP_WRITE, flags);
> -	iomap_dio_submit_bio(dio, iomap, bio);
> +	iomap_dio_submit_bio(dio, iomap, bio, pos);
>  }
>  
>  static loff_t
> @@ -299,11 +303,11 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
>  		}
>  
>  		dio->size += n;
> -		pos += n;
>  		copied += n;
>  
>  		nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES);
> -		iomap_dio_submit_bio(dio, iomap, bio);
> +		iomap_dio_submit_bio(dio, iomap, bio, pos);
> +		pos += n;
>  	} while (nr_pages);
>  
>  	/*
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 8b09463dae0d..2b093a23ef1c 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -252,6 +252,8 @@ int iomap_writepages(struct address_space *mapping,
>  struct iomap_dio_ops {
>  	int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
>  		      unsigned flags);
> +	blk_qc_t (*submit_io)(struct bio *bio, struct file *file,
> +			  loff_t file_offset);
>  };
>  
>  ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> -- 
> 2.16.4
>