Re: [PATCH 1/2] fs: Replace direct ->bmap calls by bmap()

[Carlos Maiolino <cmaiolino@redhat.com>]

On Wed, Sep 05, 2018 at 09:23:26AM -0500, Eric Sandeen wrote:
> On 9/5/18 8:57 AM, Carlos Maiolino wrote:
> > Prepare the field to use ->fiemap for FIBMAP ioctl
> > 
> > Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> > ---
> >  fs/cachefiles/rdwr.c |  5 ++---
> >  fs/ecryptfs/mmap.c   |  5 ++---
> >  fs/ioctl.c           | 14 ++++++++------
> >  3 files changed, 12 insertions(+), 12 deletions(-)
> > 
> > diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
> > index 40f7595aad10..186e203d64a7 100644
> > --- a/fs/cachefiles/rdwr.c
> > +++ b/fs/cachefiles/rdwr.c
> > @@ -435,7 +435,7 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
> >  	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?  OTOH, what will this code do if bmap() finds that there
> is no ->bmap present and returns 0?
> 
> > +	res = bmap(inode, block);
> > +
> > +	if (res)
> > +		return put_user(res, p);
> > +	else
> > +		return -EINVAL;
> 
> So now mapping a hole will return -EINVAL?  I don't think that change
> in behavior is ok.
> 

Thanks for catching it, I messed the return value here.

I'm going to think about your 2 points for the next review and work on a real
patch for retiring ->bmap once I've got more information now.


> -Eric
> 
> >  }
> >  
> >  /**
> > 
> 

-- 
Carlos