Re: [PATCH 1/2] md: disable WRITE SAME if it fails for linear/raid0

[Shaohua Li <shli@kernel.org>]

On Wed, Nov 30, 2016 at 04:39:11PM -0800, Shaohua Li wrote:
> This makes md do the same thing as dm for write same IO failure. Please
> see 7eee4ae(dm: disable WRITE SAME if it fails) for details why we need
> this.
> 
> Also reported here: https://bugzilla.kernel.org/show_bug.cgi?id=118581

Sitsofe,

can you give a shot of the patch please? It works well here, but would
appreciate if you could test it.

Thanks,
Shaohua
 
> Signed-off-by: Shaohua Li <shli@fb.com>
> ---
>  drivers/md/linear.c |  2 ++
>  drivers/md/md.c     | 42 ++++++++++++++++++++++++++++++++++++++++++
>  drivers/md/md.h     |  2 ++
>  drivers/md/raid0.c  |  2 ++
>  4 files changed, 48 insertions(+)
> 
> diff --git a/drivers/md/linear.c b/drivers/md/linear.c
> index 5975c99..d3c7b4d 100644
> --- a/drivers/md/linear.c
> +++ b/drivers/md/linear.c
> @@ -262,6 +262,8 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio)
>  				trace_block_bio_remap(bdev_get_queue(split->bi_bdev),
>  						      split, disk_devt(mddev->gendisk),
>  						      bio_sector);
> +			if (bio_op(split) == REQ_OP_WRITE_SAME)
> +				md_writesame_setup(mddev, split);
>  			generic_make_request(split);
>  		}
>  	} while (split != bio);
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index c7894fb..5e6efcd 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -312,6 +312,48 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)
>  	return BLK_QC_T_NONE;
>  }
>  
> +struct md_writesame_data {
> +	bio_end_io_t *orig_endio;
> +	void *orig_private;
> +	struct mddev *mddev;
> +};
> +
> +static void md_writesame_endio(struct bio *bio)
> +{
> +	struct md_writesame_data *data = bio->bi_private;
> +
> +	if (bio->bi_error == -EREMOTEIO &&
> +	    !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors)
> +		data->mddev->queue->limits.max_write_same_sectors = 0;
> +
> +	bio->bi_private = data->orig_private;
> +	bio->bi_end_io = data->orig_endio;
> +	bio_endio(bio);
> +
> +	kfree(data);
> +}
> +
> +void md_writesame_setup(struct mddev *mddev, struct bio *bio)
> +{
> +	struct md_writesame_data *data;
> +
> +	/*
> +	 * this failure means we ignore a chance to handle writesame failure,
> +	 * which isn't critcal, we can handle the failure if new writesame IO
> +	 * comes
> +	 */
> +	data = kmalloc(sizeof(*data), GFP_NOIO | __GFP_NORETRY);
> +	if (!data)
> +		return;
> +	data->orig_endio = bio->bi_end_io;
> +	data->orig_private = bio->bi_private;
> +	data->mddev = mddev;
> +
> +	bio->bi_private = data;
> +	bio->bi_end_io = md_writesame_endio;
> +}
> +EXPORT_SYMBOL_GPL(md_writesame_setup);
> +
>  /* mddev_suspend makes sure no new requests are submitted
>   * to the device, and that any requests that have been submitted
>   * are completely handled.
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index 5c08f84..2d1556b 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -700,4 +700,6 @@ static inline int mddev_is_clustered(struct mddev *mddev)
>  {
>  	return mddev->cluster_info && mddev->bitmap_info.nodes > 1;
>  }
> +
> +extern void md_writesame_setup(struct mddev *mddev, struct bio *bio);
>  #endif /* _MD_MD_H */
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index e628f18..4811116 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -498,6 +498,8 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio)
>  				trace_block_bio_remap(bdev_get_queue(split->bi_bdev),
>  						      split, disk_devt(mddev->gendisk),
>  						      bio_sector);
> +			if (bio_op(split) == REQ_OP_WRITE_SAME)
> +				md_writesame_setup(mddev, split);
>  			generic_make_request(split);
>  		}
>  	} while (split != bio);
> -- 
> 2.9.3
> 
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