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From: Christoph Hellwig <hch@lst.de>
To: Eric Sandeen <sandeen@redhat.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>,
	linux-fsdevel@vger.kernel.org, hch@lst.de, david@fromorbit.com
Subject: Re: [PATCH 1/2] fs: Replace direct ->bmap calls by bmap()
Date: Wed, 5 Sep 2018 20:55:39 +0200	[thread overview]
Message-ID: <20180905185539.GA423@lst.de> (raw)
In-Reply-To: <b7bfbb00-a4f7-5131-2085-0311cb2d4b10@redhat.com>

On Wed, Sep 05, 2018 at 09:23:26AM -0500, Eric Sandeen wrote:
> >  	block0 = page->index;
> >  	block0 <<= shift;
> >  
> > -	block = inode->i_mapping->a_ops->bmap(inode->i_mapping, block0);
> > +	block = bmap(inode, block0);
> 
> Prior to this there's an ASSERT that inode->i_mapping->a_ops->bmap
> exists.  Should that stay, if the goal is to move all ->bmap use out
> of calling code?

I think it needs to go away.

> OTOH, what will this code do if bmap() finds that there
> is no ->bmap present and returns 0?

I think we just need to fix the bmap() prototype so that it can return
error, which would be very useful for various reasons.  Something like
this:

int bmap(struct address_space *mapping, sector_t *block)
{
	if (!mapping->a_ops->bmap)
		return -EINVAL;
	*block = mapping->a_ops->bmap(mapping, *block);
	return 0;
}

then add fiemap support with real error handling later.

  reply	other threads:[~2018-09-05 23:23 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-05 13:57 [PATCH RFC 0/2] ->bmap interface retirement Carlos Maiolino
2018-09-05 13:57 ` [PATCH 1/2] fs: Replace direct ->bmap calls by bmap() Carlos Maiolino
2018-09-05 14:23   ` Eric Sandeen
2018-09-05 18:55     ` Christoph Hellwig [this message]
2018-09-06  8:04       ` Carlos Maiolino
2018-09-06  8:03     ` Carlos Maiolino
2018-09-05 13:57 ` [PATCH 2/2] Use fiemap internal infra-structure to handle FIBMAP Carlos Maiolino
2018-09-05 14:31   ` Matthew Wilcox
2018-09-05 18:56     ` Christoph Hellwig
2018-09-06  8:31       ` Carlos Maiolino
2018-09-10  7:50         ` Christoph Hellwig
2018-09-10 10:31           ` Carlos Maiolino
2018-09-26 13:34           ` Carlos Maiolino
2018-09-06  8:18     ` Carlos Maiolino
2018-09-05 14:40   ` Eric Sandeen
2018-09-06  8:12     ` Carlos Maiolino
2018-09-06 15:53       ` Eric Sandeen

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