[LTP] [PATCH 1/2] scsi_debug/tlibio/lio_write_buffer: Always return total amount of written bytes

[Petr Vorel]

Hi Konstantin,

> Sometimes we got failures like:
>  growfiles(gf217): 65884 growfiles.c/2262: 104203 tlibio.c/744 write(3, buf, 5000) returned=2288
>  growfiles(gf217): 65884 growfiles.c/1765: 104203 Hit max errors value of 1
>  gf217       1  TFAIL  :  growfiles.c:134: Test failed

I wonder on which circumstances do you get this error. Running on container?

> Which looked strange as partial write is something usual and valid.
> It turned out that lio_write_buffer() has the code cycle writes in case
> of a partial write happens, but it anyway returns the amount of bytes
> written by the LAST write.

> And upper growfile() consider the returned amount from
> lio_write_buffer() to be less than it tried to write and fails the
> testcase.

> Fix lio_write_buffer() to always return total bytes written, even in
> case partial writes.

> Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
> ---
>  lib/tlibio.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)

> diff --git a/lib/tlibio.c b/lib/tlibio.c
> index cc110d1c9..8298e2de9 100644
> --- a/lib/tlibio.c
> +++ b/lib/tlibio.c
> @@ -539,6 +539,8 @@ int lio_write_buffer(int fd,		/* open file descriptor */
>  		long wrd)	/* to allow future features, use zero for now */
>  {
>  	int ret = 0;		/* syscall return or used to get random method */
> +	int totally_written = 0;/* as we cycle writes in case of partial writes, */
> +				/* we have to report up total bytes written */

Nit: I'd do multiline comment (much more readable):

	/* as we cycle writes in case of partial writes,
	 * we have to report up total bytes written */
	int totally_written = 0;

Otherwise LGTM.

Reviewed-by: Petr Vorel <pvorel@suse.cz>

>  	char *io_type;		/* Holds string of type of io */
>  	int omethod = method;
>  	int listio_cmd;		/* Holds the listio/lio_listio cmd */
> @@ -745,13 +747,14 @@ int lio_write_buffer(int fd,		/* open file descriptor */
>  						fd, size, ret);
>  					size -= ret;
>  					buffer += ret;
> +					totally_written += ret;
>  				} else {
>  					if (Debug_level > 1)
>  						printf
>  						    ("DEBUG %s/%d: write completed without error (ret %d)\n",
>  						     __FILE__, __LINE__, ret);

BTW growfiles.c and other files based on tlibio.c would deserve big cleanup and
rewrite into new API.

Kind regards,
Petr

> -					return ret;
> +					return totally_written + ret;
>  				}
>  			}
>  			wait4sync_io(fd, 0);