Re: don't use ->bd_inode to access the block device size

Anton Altaparmakov
2021-10-14T09:53:13Z

Hi Christoph,

> On 14 Oct 2021, at 07:28, Christoph Hellwig <hch@lst.de> wrote:
>
> On Wed, Oct 13, 2021 at 07:10:13AM +0200, Christoph Hellwig wrote:
>> I wondered about adding a helper for looking at the size in byte units
>> to avoid the SECTOR_SHIFT shifts in various places. But given that
>> I could not come up with a good name and block devices fundamentally
>> work in sector size granularity I decided against that.
>
> So it seems like the biggest review feedback is that we should have
> such a helper. I think the bdev_size name is the worst as size does
> not imply a particular unit. bdev_nr_bytes is a little better but I'm
> not too happy. Any other suggestions or strong opinions?

bdev_byte_size() would seem to address your concerns?

bdev_nr_bytes() would work though - it is analogous to bdev_nr_sectors() after all.

No strong opinion here but I do agree with you that bdev_size() is a bad choice for sure. It is bound to cause bugs down the line when people forget what unit it is in.

Best regards,

Anton
--
Anton Altaparmakov <anton at tuxera.com> (replace at with @)
Lead in File System Development, Tuxera Inc., http://www.tuxera.com/
Linux NTFS maintainer