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 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?

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
>