Re: [Qemu-devel] [PATCH v3 06/13] 9p: darwin: Ignore O_{NOATIME, DIRECT}

[Greg Kurz]

On Sat, 16 Jun 2018 20:56:50 -0400
Keno Fischer <address@hidden> wrote:

> Darwin doesn't have either of these flags. Darwin does have
> F_NOCACHE, which is similar to O_DIRECT, but has different
> enough semantics that other projects don't generally map
> them automatically. In any case, we don't support O_DIRECT
> on Linux at the moment either.
> 
> Signed-off-by: Keno Fischer <address@hidden>
> ---

Reviewed-by: Greg Kurz <address@hidden>

>  hw/9pfs/9p.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index 06139c9..e650459 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -123,11 +123,18 @@ static int dotl_to_open_flags(int flags)
>          { P9_DOTL_NONBLOCK, O_NONBLOCK } ,
>          { P9_DOTL_DSYNC, O_DSYNC },
>          { P9_DOTL_FASYNC, FASYNC },
> +#ifndef CONFIG_DARWIN
> +        { P9_DOTL_NOATIME, O_NOATIME },
> +        /* On Darwin, we could map to F_NOCACHE, which is
> +           similar, but doesn't quite have the same
> +           semantics. However, we don't support O_DIRECT
> +           even on linux at the moment, so we just ignore
> +           it here. */
>          { P9_DOTL_DIRECT, O_DIRECT },
> +#endif
>          { P9_DOTL_LARGEFILE, O_LARGEFILE },
>          { P9_DOTL_DIRECTORY, O_DIRECTORY },
>          { P9_DOTL_NOFOLLOW, O_NOFOLLOW },
> -        { P9_DOTL_NOATIME, O_NOATIME },
>          { P9_DOTL_SYNC, O_SYNC },
>      };
>  
> @@ -156,10 +163,12 @@ static int get_dotl_openflags(V9fsState *s, int oflags)
>       */
>      flags = dotl_to_open_flags(oflags);
>      flags &= ~(O_NOCTTY | O_ASYNC | O_CREAT);
> +#ifndef CONFIG_DARWIN
>      /*
>       * Ignore direct disk access hint until the server supports it.
>       */
>      flags &= ~O_DIRECT;
> +#endif
>      return flags;
>  }
>