Re: [PATCH 5/5] 9pfs: fix removing non-existent POSIX ACL xattr on macOS host

[Greg Kurz]

On Tue, 19 Apr 2022 13:43:30 +0200
Christian Schoenebeck <qemu_oss@crudebyte.com> wrote:

> When mapped POSIX ACL is used, we are ignoring errors when trying
> to remove a POSIX ACL xattr that does not exist. On Linux hosts we
> would get ENODATA in such cases, on macOS hosts however we get
> ENOATTR instead, so ignore ENOATTR errors as well.
> 
> This patch fixes e.g. a command on Linux guest like:
> 
>   cp --preserve=mode old new
> 
> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> ---
>  hw/9pfs/9p-posix-acl.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/9pfs/9p-posix-acl.c b/hw/9pfs/9p-posix-acl.c
> index eadae270dd..2bf155f941 100644
> --- a/hw/9pfs/9p-posix-acl.c
> +++ b/hw/9pfs/9p-posix-acl.c
> @@ -65,7 +65,13 @@ static int mp_pacl_removexattr(FsContext *ctx,
>      int ret;
>  
>      ret = local_removexattr_nofollow(ctx, path, MAP_ACL_ACCESS);
> -    if (ret == -1 && errno == ENODATA) {
> +    if (ret == -1 &&
> +          (errno == ENODATA
> +#ifdef ENOATTR
> +          || errno == ENOATTR
> +#endif
> +          )

We already have this in <qemu/xattr.h> which is included by
9p-posix-acl.c :

/*
 * Modern distributions (e.g. Fedora 15), have no libattr.so, place attr.h
 * in /usr/include/sys, and don't have ENOATTR.
 */


#ifdef CONFIG_LIBATTR
#  include <attr/xattr.h>
#else
#  if !defined(ENOATTR)
#    define ENOATTR ENODATA
#  endif
#  include <sys/xattr.h>
#endif

I guess this patch could just s/ENODATA/ENOATTR/ to avoid the
extra ifdefery.

> +    ) {
>          /*
>           * We don't get ENODATA error when trying to remove a
>           * posix acl that is not present. So don't throw the error