On Wed, Sep 25, 2019 at 03:16:55PM +0800, Su Yanjun wrote:
> On some linux distros(RHEL7, centos 7) copy_file_range uses
> general implementation (splice interface). splice interace
> uses pipe_to_file. pipe_to_file only work for different page.
> The userspace cant's be aware of such error because copy_file_range
> returns ok too.
This looks like a kernel bug to me.
> So for such case when copy_file_range return we read back data
> then check it.
Yeah, I think we should make sure the data copied is correct.
>
> Signed-off-by: Su Yanjun <suyj.fnst@xxxxxxxxxxxxxx>
> ---
> ltp/fsx.c | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/ltp/fsx.c b/ltp/fsx.c
> index 06d08e4..0439430 100644
> --- a/ltp/fsx.c
> +++ b/ltp/fsx.c
> @@ -1602,6 +1602,7 @@ do_copy_range(unsigned offset, unsigned length, unsigned dest)
> size_t olen;
> ssize_t nr;
> int tries = 0;
> + int ret = 0;
>
> if (length == 0) {
> if (!quiet && testcalls > simulatedopcount)
> @@ -1665,6 +1666,37 @@ do_copy_range(unsigned offset, unsigned length, unsigned dest)
> memset(good_buf + file_size, '\0', dest - file_size);
> if (dest + length > file_size)
> file_size = dest + length;
> + /*
> + * Although copy_file_range returns ok
> + * for some linux distros that use general implementation
> + * (splice interface) such as RHEL 7, centos 7 that use
> + * pipe_to_file will cause test fail.
> + *
> + * Here we add a little more check here for copy_file_range
> + * We read copied data then check it. If check fail here
> + * then report it.
> + */
Above comments seem like not necessary, the content check is inspired by
Rthis HEL7 issue, but not the main purpose.
> + ret = lseek(fd, (off_t)dest, SEEK_SET);
> + if (ret == (off_t)-1) {
> + prterr("doread: lseek");
^^^^^^^ not doread
> + report_failure(140);
Use a different failure number than that in doread, i.e. don't copy the
code from doread.
> + }
> + ret = fsxread(fd, temp_buf, length, dest);
> + if (ret != length) {
> + if (ret == -1)
> + prterr("doread: read");
> + else
> + prt("short read: 0x%x bytes instead of 0x%x\n",
> + ret, length);
Same here, not doread, and weired indention above.
> + report_failure(141);
> + }
> + if (memcmp(good_buf+dest, temp_buf, length) != 0) {
> + prt("copy range: 0x%x to 0x%x at 0x%x\n", offset,
> + offset + length, dest);
> + prterr("do_copy_range:");
> + report_failure(161);
I think we could take use of check_buffers().
And similar check could be added to do_clone_range as well, I think.
Thanks,
Eryu
> +
> + }
> }
>
> #else
> --
> 2.7.4
>
>
>
