[Devel] [PATCH RH9 v2 1/8] block/fops: add llseek_hole to blockdevops

[Alexander Atanasov]

On 16.08.23 12:32, Andrey Zhadchenko wrote:
> Add new function for block_device_operations, which will be used
> for SEEK_HOLE and SEEK_DATA llseek calls
> 
> Feature: dm: implement SEEK_HOLE for dm-qcow2 and dm-ploop
> https://jira.vzint.dev/browse/PSBM-145746
> Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
> 
> ---
> v2: fix critical bug: do not (SEEK_HOLE | SEEK_DATA) as they are
> rather continious enums
> 
>   block/fops.c           | 13 +++++++++++++
>   include/linux/blkdev.h |  1 +
>   2 files changed, 14 insertions(+)
> 
> diff --git a/block/fops.c b/block/fops.c
> index 0d07e6f6b284..528aa1288169 100644
> --- a/block/fops.c
> +++ b/block/fops.c
> @@ -431,11 +431,24 @@ const struct address_space_operations def_blk_aops = {
>   static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
>   {
>   	struct inode *bd_inode = bdev_file_inode(file);
> +	struct block_device *bdev = I_BDEV(bd_inode);
> +	bool is_llseek_hole;
>   	loff_t retval;
>   
> +	is_llseek_hole = (whence == SEEK_HOLE || whence == SEEK_DATA);
> +	if (is_llseek_hole && bdev->bd_disk->fops->llseek_hole) {
> +		retval = bdev->bd_disk->fops->llseek_hole(bdev, offset, whence);
> +		if (retval < 0)
> +			return retval;
> +
> +		offset = retval;
> +		whence = SEEK_SET;
> +	}
> +
>   	inode_lock(bd_inode);
>   	retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
>   	inode_unlock(bd_inode);
> +
>   	return retval;
>   }
>   
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 8b82a63500fc..5c10935cb38e 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1482,6 +1482,7 @@ struct block_device_operations {
>   	int (*getgeo)(struct block_device *, struct hd_geometry *);
>   	int (*set_read_only)(struct block_device *bdev, bool ro);
>   	void (*free_disk)(struct gendisk *disk);
> +	loff_t (*llseek_hole)(struct block_device *bdev, loff_t offset, int whence);
>   	/* this callback is with swap_lock and sometimes page table lock held */
>   	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
>   	int (*report_zones)(struct gendisk *, sector_t sector,


LGTM

-- 
Regards,
Alexander Atanasov