Re: [PATCH 2/5] [FAT] Let the block device know when sectors can be discarded

[David Woodhouse <dwmw2@infradead.org>]

On Thu, 2008-08-07 at 01:40 +0900, OGAWA Hirofumi wrote:
> Perhaps, after checking cluster-chain corruption is better. Thanks.

That can be done, but not like that, I think. At the point you added the
blkdev_issue_discard() call, the value of 'cluster' has already changed.

So if the chain being freed is clusters 10, 11 and 12, your version of
the patch will attempt to discard clusters 11, 12 and 0xFFFF (EOF).


On Thu, 2008-08-07 at 02:14 +0900, OGAWA Hirofumi wrote:
> Ah, blkdev_issue_discard() assumes blocksize is 512bytes, um...

Doesn't everything? I did consider using q->hardsect_size, but decided
that was probably the wrong thing to do. I don't know. Jens?

> blkdev_issue_discard() takes bytes,

-EPARSE. It takes sectors at the moment -- do you mean you _want_ it to
take bytes? 

> and instead add some helpers for sb or inode?

I suppose we could; I'm not really so sure we need them.
inode->i_sb->s_bdev isn't exactly hard...

-- 
dwmw2