Re: [PATCH 04/11] vfs: add missing checks to copy_file_range

From: Dave Chinner <david@fromorbit.com>
To: Olga Kornievskaia <olga.kornievskaia@gmail.com>
Cc: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-nfs <linux-nfs@vger.kernel.org>,
	linux-unionfs@vger.kernel.org, ceph-devel@vger.kernel.org,
	linux-cifs@vger.kernel.org
Subject: Re: [PATCH 04/11] vfs: add missing checks to copy_file_range
Date: Tue, 4 Dec 2018 10:04:54 +1100	[thread overview]
Message-ID: <20181203230454.GI6311@dastard> (raw)
In-Reply-To: <CAN-5tyH2RX_7SkvipnKkM2EF6_cHJ9qG6g9W+Ufb9+5r-Zb4hg@mail.gmail.com>

On Mon, Dec 03, 2018 at 04:33:30PM -0500, Olga Kornievskaia wrote:
> On Mon, Dec 3, 2018 at 3:34 AM Dave Chinner <david@fromorbit.com> wrote:
> > --- a/include/linux/fs.h
> > +++ b/include/linux/fs.h
> > @@ -3022,6 +3022,9 @@ extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
> >  extern int generic_remap_checks(struct file *file_in, loff_t pos_in,
> >                                 struct file *file_out, loff_t pos_out,
> >                                 loff_t *count, unsigned int remap_flags);
> > +extern int generic_copy_file_checks(struct file *file_in, loff_t pos_in,
> > +                               struct file *file_out, loff_t pos_out,
> > +                               size_t *count, unsigned int flags);
> >  extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
> >  extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
> >  extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
> > diff --git a/mm/filemap.c b/mm/filemap.c
> > index 81adec8ee02c..0a170425935b 100644
> > --- a/mm/filemap.c
> > +++ b/mm/filemap.c
> > @@ -2975,6 +2975,75 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in,
> >         return 0;
> >  }
> >
> > +
> > +/*
> > + * Performs necessary checks before doing a file copy
> > + *
> > + * Can adjust amount of bytes to copy
> > + * Returns appropriate error code that caller should return or
> > + * zero in case the copy should be allowed.
> > + */
> > +int generic_copy_file_checks(struct file *file_in, loff_t pos_in,
> > +                        struct file *file_out, loff_t pos_out,
> > +                        size_t *req_count, unsigned int flags)
> > +{
> > +       struct inode *inode_in = file_inode(file_in);
> > +       struct inode *inode_out = file_inode(file_out);
> > +       uint64_t count = *req_count;
> > +       uint64_t bcount;
> > +       loff_t size_in, size_out;
> > +       loff_t bs = inode_out->i_sb->s_blocksize;
> > +       int ret;
> 
> I got compile warnings:
> 
> mm/filemap.c: In function ‘generic_copy_file_checks’:
> mm/filemap.c:2995:9: warning: unused variable ‘bs’ [-Wunused-variable]
>   loff_t bs = inode_out->i_sb->s_blocksize;
>          ^
> mm/filemap.c:2993:11: warning: unused variable ‘bcount’ [-Wunused-variable]
>   uint64_t bcount;

Strange. Yes, they certainly are there when I compile my stack up to
this point, but when I compile the whole series they aren't there.

I'll fix it up.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com