[PATCH 2/2] block: skip the fsync_bdev call in del_gendisk for surprise removals

[Markus Blöchl]

On Wed, Feb 16, 2022 at 04:09:01PM +0100, Christoph Hellwig wrote:
> For surprise removals that have already marked the disk dead, there is
> no point in calling fsync_bdev as all I/O will fail anyway, so skip it.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> ---
>  block/genhd.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/block/genhd.c b/block/genhd.c
> index 626c8406f21a6..f68bdfe4f883b 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -584,7 +584,14 @@ void del_gendisk(struct gendisk *disk)
>  	blk_drop_partitions(disk);

blk_drop_partitions() also invokes fsync_bdev() via delete_partition().
So why treat them differently?

>  	mutex_unlock(&disk->open_mutex);
>  
> -	fsync_bdev(disk->part0);
> +	/*
> +	 * If this is not a surprise removal see if there is a file system
> +	 * mounted on this device and sync it (although this won't work for
> +	 * partitions).  For surprise removals that have already marked the
> +	 * disk dead skip this call as no I/O is possible anyway.
> +	 */
> +	if (!test_bit(GD_DEAD, &disk->state))
> +		fsync_bdev(disk->part0);
>  	__invalidate_device(disk->part0, true);
>  
>  	/*
> -- 
> 2.30.2
>