[PATCH] dd: call fsync() only once before exiting if conv=fsync is specified

[Ari Sundholm]

Hi!

On 03/14/2017 06:44 PM, Rostislav Skudnov wrote:
> Signed-off-by: Rostislav Skudnov <rostislav at tuxera.com>

It would probably be useful to tell why this change was made: it makes 
the behavior consistent with coreutils dd and fixes performance problems 
caused by calling fsync() over and over again.

> ---
>  coreutils/dd.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/coreutils/dd.c b/coreutils/dd.c
> index 5e68087..d89c0ae 100644
> --- a/coreutils/dd.c
> +++ b/coreutils/dd.c
> @@ -532,17 +532,17 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
>  			if (write_and_stats(ibuf, n, obs, outfile))
>  				goto out_status;
>  		}
> -
> -		if (G.flags & FLAG_FSYNC) {
> -			if (fsync(ofd) < 0)
> -				goto die_outfile;
> -		}
>  	}
>
>  	if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
>  		if (write_and_stats(obuf, oc, obs, outfile))
>  			goto out_status;
>  	}
> +
> +	if (G.flags & FLAG_FSYNC) {
> +		if (fsync(ofd) < 0)
> +			goto die_outfile;
> +	}
>  	if (close(ifd) < 0) {
>   die_infile:
>  		bb_simple_perror_msg_and_die(infile);
>

Maybe a blank line between the closing brace and the next if statement 
to make the look more consistent?

Best regards,
Ari Sundholm
ari at tuxera.com