Re: [PATCH] xfsprogs: io/copy_range: cover corner case (fd_in == fd_out)

[Zorro Lang <zlang@redhat.com>]

On Tue, Sep 03, 2019 at 06:56:32PM +0800, Jianhong.Yin wrote:
> Related bug:
>   copy_file_range return "Invalid argument" when copy in the same file
>   https://bugzilla.kernel.org/show_bug.cgi?id=202935
> 
> if argument of option -f is "-", use current file->fd as fd_in
> 
> Usage:
>   xfs_io -c 'copy_range -f -' some_file
> 
> Signed-off-by: Jianhong Yin <yin-jianhong@163.com>
> ---

Hi,

Actually, I'm thinking about if you need same 'fd' or same file path?
If you just need same file path, I think

  # xfs_io -c "copy_range testfile" testfile

already can help that. The only one problem stop you doing that is
"copy_dst_truncate()".

If all above I suppose is right, we can turn to talk about if that
copy_dst_truncate() is necessary, or how can we skip it.

Thanks,
Zorro

>  io/copy_file_range.c | 27 ++++++++++++++++++---------
>  1 file changed, 18 insertions(+), 9 deletions(-)
> 
> diff --git a/io/copy_file_range.c b/io/copy_file_range.c
> index b7b9fd88..2dde8a31 100644
> --- a/io/copy_file_range.c
> +++ b/io/copy_file_range.c
> @@ -28,6 +28,7 @@ copy_range_help(void)
>                            at position 0\n\
>   'copy_range -f 2' - copies all bytes from open file 2 into the current open file\n\
>                            at position 0\n\
> + 'copy_range -f -' - copies all bytes from current open file append the current open file\n\
>  "));
>  }
>  
> @@ -114,11 +115,15 @@ copy_range_f(int argc, char **argv)
>  			}
>  			break;
>  		case 'f':
> -			src_file_nr = atoi(argv[1]);
> -			if (src_file_nr < 0 || src_file_nr >= filecount) {
> -				printf(_("file value %d is out of range (0-%d)\n"),
> -					src_file_nr, filecount - 1);
> -				return 0;
> +			if (strcmp(argv[1], "-"))
> +				src_file_nr = (file - &filetable[0]) / sizeof(fileio_t);
> +			else {
> +				src_file_nr = atoi(argv[1]);
> +				if (src_file_nr < 0 || src_file_nr >= filecount) {
> +					printf(_("file value %d is out of range (0-%d)\n"),
> +						src_file_nr, filecount - 1);
> +					return 0;
> +				}
>  			}
>  			/* Expect no src_path arg */
>  			src_path_arg = 0;
> @@ -147,10 +152,14 @@ copy_range_f(int argc, char **argv)
>  		}
>  		len = sz;
>  
> -		ret = copy_dst_truncate();
> -		if (ret < 0) {
> -			ret = 1;
> -			goto out;
> +		if (fd != file->fd) {
> +			ret = copy_dst_truncate();
> +			if (ret < 0) {
> +				ret = 1;
> +				goto out;
> +			}
> +		} else {
> +			dst = sz;
>  		}
>  	}
>  
> -- 
> 2.17.2
>