Re: [PATCH 2/2] xfsprogs: copy_range: let = (src_size - src_offset) if len omitted

[Zorro Lang <zlang@redhat.com>]

On Thu, Sep 05, 2019 at 02:04:31AM -0400, Jianhong Yin wrote:
> 
> 
> ----- 原始邮件 -----
> > 发件人: "Zorro Lang" <zlang@redhat.com>
> > 收件人: "Jianhong.Yin" <yin-jianhong@163.com>
> > 抄送: linux-xfs@vger.kernel.org, jiyin@redhat.com
> > 发送时间: 星期四, 2019年 9 月 05日 下午 2:01:32
> > 主题: Re: [PATCH 2/2] xfsprogs: copy_range: let = (src_size - src_offset) if len omitted
> > 
> > On Thu, Sep 05, 2019 at 01:31:52PM +0800, Jianhong.Yin wrote:
> > > add update man page.
> > > 
> > > Signed-off-by: Jianhong Yin <yin-jianhong@163.com>
> > > ---
> > 
> > I think these can be in one patch, but anyway...
> > 
> > >  io/copy_file_range.c | 7 +++++--
> > >  man/man8/xfs_io.8    | 9 +++------
> > >  2 files changed, 8 insertions(+), 8 deletions(-)
> > > 
> > > diff --git a/io/copy_file_range.c b/io/copy_file_range.c
> > > index 283f5094..02d50e53 100644
> > > --- a/io/copy_file_range.c
> > > +++ b/io/copy_file_range.c
> > > @@ -72,6 +72,7 @@ copy_range_f(int argc, char **argv)
> > >  	long long src = 0;
> > >  	long long dst = 0;
> > >  	size_t len = 0;
> > > +	int len_ommited = 1;
> > >  	int opt;
> > >  	int ret;
> > >  	int fd;
> > > @@ -103,6 +104,7 @@ copy_range_f(int argc, char **argv)
> > >  				printf(_("invalid length -- %s\n"), optarg);
> > >  				return 0;
> > >  			}
> > > +			len_ommited = 0;
> > >  			break;
> > >  		case 'f':
> > >  			src_file_nr = atoi(argv[1]);
> > > @@ -128,7 +130,7 @@ copy_range_f(int argc, char **argv)
> > >  		fd = filetable[src_file_nr].fd;
> > >  	}
> > >  
> > > -	if (src == 0 && dst == 0 && len == 0) {
> > > +	if (len_ommited) {
> > >  		off64_t	sz;
> > >  
> > >  		sz = copy_src_filesize(fd);
> > > @@ -136,7 +138,8 @@ copy_range_f(int argc, char **argv)
> > >  			ret = 1;
> > >  			goto out;
> > >  		}
> > > -		len = sz;
> > > +		if (sz > src)
> > > +			len = sz - src;
> > 
> > What about file size < offset?
> just keep the default value 0,
> 
> because QE/tester might want to see what happen
> when give an offset(> fsize) to copy_file_range()
>   #note: This tool was made for test/debug copy_file_range()

Hmm, that's a good reason:)

> 
> Jianhong
> 
> > 
> > Maybe we can do like this?:
> > 
> >     sz = copy_src_filesize(fd);
> >     if (sz < 0 || (unsigned long long)sz > SIZE_MAX || sz < src) {
> >         ret = 1;
> >         goto out;
> >     }
> >     len = sz - src;
> > 
> > Thanks,
> > Zorro
> > 
> > >  	}
> > >  
> > >  	ret = copy_file_range_cmd(fd, &src, &dst, len);
> > > diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
> > > index 6e064bdd..f5f1c4fc 100644
> > > --- a/man/man8/xfs_io.8
> > > +++ b/man/man8/xfs_io.8
> > > @@ -669,13 +669,10 @@ The source must be specified either by path
> > >  or as another open file
> > >  .RB ( \-f ).
> > >  If
> > > -.I src_file
> > > -.IR src_offset ,
> > > -.IR dst_offset ,
> > > -and
> > >  .I length
> > > -are omitted the contents of src_file will be copied to the beginning of
> > > the
> > > -open file, overwriting any data already there.
> > > +is omitted will use
> > > +.I src_file
> > > +(file size - src_offset) instead.
> > >  .RS 1.0i
> > >  .PD 0
> > >  .TP 0.4i
> > > --
> > > 2.21.0
> > > 
> >