On Wed, Sep 04, 2019 at 02:32:22PM +0800, Jianhong.Yin wrote:
> now if we do copy_range in same file without any extra option
> will truncate the file, and not any document indicate this default
> action. that's risky to users.
>
> '''
> $ LANG=C ll testfile
> -rw-rw-r--. 1 yjh yjh 4054 Sep 4 14:22 testfile
> $ ./xfs_io -c 'copy_range testfile' testfile
> $ LANG=C ll testfile
> -rw-rw-r--. 1 yjh yjh 4054 Sep 4 14:23 testfile
> '''
>
> Signed-off-by: Jianhong Yin <yin-jianhong@xxxxxxx>
> ---
> io/copy_file_range.c | 23 +++++++++++++++++++----
> 1 file changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/io/copy_file_range.c b/io/copy_file_range.c
> index b7b9fd88..487041c0 100644
> --- a/io/copy_file_range.c
> +++ b/io/copy_file_range.c
> @@ -75,6 +75,19 @@ copy_dst_truncate(void)
> return ret;
> }
>
> +int is_same_file(int fd1, int fd2) {
> + struct stat stat1, stat2;
> + if (fstat(fd1, &stat1) < 0) {
> + perror("fstat");
> + return -1;
> + }
> + if (fstat(fd2, &stat2) < 0) {
> + perror("fstat");
> + return -1;
> + }
> + return (stat1.st_dev == stat2.st_dev) && (stat1.st_ino == stat2.st_ino);
> +}
> +
> static int
> copy_range_f(int argc, char **argv)
> {
> @@ -147,10 +160,12 @@ copy_range_f(int argc, char **argv)
> }
> len = sz;
>
> - ret = copy_dst_truncate();
> - if (ret < 0) {
> - ret = 1;
> - goto out;
> + if (!is_same_file(fd, file->fd)) {
Uggggh, why does xfs_io copy_range have this weird behavior? It should
be a simple wrapper for copy_file_range (the syscall) and nothing else.
The code patch looks fine for solving this edge case, but we really
shouldn't have this "extra" functionality in a debugging tool that
should be athin wrapper around the syscall for xfstests purposes.
--D
> + ret = copy_dst_truncate();
> + if (ret < 0) {
> + ret = 1;
> + goto out;
> + }
> }
> }
>
> --
> 2.17.2
>
