Subject: Re: linux-next: manual merge of the akpm-current tree with the btrfs tree

From: Stephen Rothwell <[email-masked]>
Date: Fri, 26 Feb 2021 10:32:50 +1100

Hi all,

On Mon, 15 Feb 2021 08:46:34 +1100 Stephen Rothwell <[email-masked]> wrote:
>
> On Wed, 27 Jan 2021 22:39:18 +1100 Stephen Rothwell <[email-masked]> wrote:
> >
> > Today's linux-next merge of the akpm-current tree got a conflict in:
> > 
> >   fs/btrfs/file.c
> > 
> > between commit:
> > 
> >   0225a20db6d8 ("btrfs: Prevent nowait or async read from doing sync IO")
> > 
> > from the btrfs tree and commit:
> > 
> >   ddcd14c48a30 ("mm/filemap: rename generic_file_buffered_read to filemap_read")
> > 
> > from the akpm-current tree.
> > 
> > I fixed it up (see below) and can carry the fix as necessary. This
> > is now fixed as far as linux-next is concerned, but any non trivial
> > conflicts should be mentioned to your upstream maintainer when your tree
> > is submitted for merging.  You may also want to consider cooperating
> > with the maintainer of the conflicting tree to minimise any particularly
> > complex conflicts.
> > 
> > diff --cc fs/btrfs/file.c
> > index 5282f456c99c,898ef7b792b7..000000000000
> > --- a/fs/btrfs/file.c
> > +++ b/fs/btrfs/file.c
> > @@@ -3629,18 -3639,7 +3629,18 @@@ static ssize_t btrfs_file_read_iter(str
> >   			return ret;
> >   	}
> >   
> >  -	return filemap_read(iocb, to, ret);
> >  +	if (iocb->ki_flags & IOCB_NOWAIT)
> >  +		iocb->ki_flags |= IOCB_NOIO;
> >  +
> > - 	ret = generic_file_buffered_read(iocb, to, ret);
> > ++	ret = filemap_read(iocb, to, ret);
> >  +
> >  +	if (iocb->ki_flags & IOCB_NOWAIT) {
> >  +		iocb->ki_flags &= ~IOCB_NOIO;
> >  +		if (ret == 0)
> >  +			ret = -EAGAIN;
> >  +	}
> >  +
> >  +	return ret;
> >   }
> >   
> >   const struct file_operations btrfs_file_operations = {  
> 
> With the merge window about to open, this is a reminder that this
> conflict still exists.
> 
> The btrfs tree commit is now
> 
>   1605f1b63c76 ("btrfs: Prevent nowait or async read from doing sync IO")

Now

  5b1c5c4216f2 ("btrfs: Prevent nowait or async read from doing sync IO")

> The akpm-current commit is now
> 
>   de45c82ebea8 ("mm/filemap: rename generic_file_buffered_read to filemap_read")

Now in Linus' tree as

  87fa0f3eb267 ("mm/filemap: rename generic_file_buffered_read to filemap_read")

This ia now a conflict between the btrfs tree and Linus' tree.
-- 
Cheers,
Stephen Rothwell