[U-Boot] [PATCH] fix: fw_env: Prevent writing error message on special files, which don't support fsync

[Michael Heimpold <mhei@heimpold.de>]

Hi Lukasz,

Am Sonntag, 27. August 2017, 13:46:22 CEST schrieb Lukasz Majewski:
> According to fsync specification [1] some special files (e.g., a pipe, FIFO,
> or socket) don't support synchronization and return either EROFS or EINVAL.
> 
> On the linux side the sys_fsync -> do_fsync() checks if the requested file
> has f_op->fsync defined. If not it returns EINVAL [2].
> 
> This commit prevents writing error messages for files (devices), which
> do not support fsync().
> 
> [1] - http://man7.org/linux/man-pages/man2/fsync.2.html
> [2] - http://elixir.free-electrons.com/linux/v4.13-rc6/source/fs/sync.c#L183
> 
> Signed-off-by: Lukasz Majewski <lukma@denx.de>
> ---
>  tools/env/fw_env.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c
> index c9c79e0..ab7d85b 100644
> --- a/tools/env/fw_env.c
> +++ b/tools/env/fw_env.c
> @@ -1088,14 +1088,16 @@ static int flash_io (int mode)
> 
>  		rc = flash_write (fd_current, fd_target, dev_target);
> 
> -		if (fsync (fd_current)) {
> +		if (fsync(fd_current) &&

nitpick: current coding style seems to be a single whitespace before
the opening bracket

> +		    !(errno == EINVAL || errno == EROFS)) {
>  			fprintf (stderr,
>  				 "fsync failed on %s: %s\n",
>  				 DEVNAME (dev_current), strerror (errno));
>  		}
> 
>  		if (HaveRedundEnv) {
> -			if (fsync (fd_target)) {
> +			if (fsync(fd_target) &&

dito

> +			    !(errno == EINVAL || errno == EROFS)) {
>  				fprintf (stderr,
>  					 "fsync failed on %s: %s\n",
>  					 DEVNAME (dev_current), strerror (errno));

Other than this nitpick:

Acked-by: Michael Heimpold <mhei@heimpold.de>

Regards,
Michael