svn commit: r230252 - head/sys/fs/tmpfs

[Kevin Lo]

Jaakko Heinonen wrote:
> Hi,

Hi Jaakko,

> On 2012-01-22, Mikolaj Golub wrote:
> >  JH> # mount -u -o ro /mnt
> >  JH> mount: tmpfs : Operation not supported
> >  JH> # mount -u -o ro,export /mnt
> >  JH> #
> > 
> > There is no error but ro is still ignored, so this is only the issue with
> > reporting. Note, the code for nullfs (as an example) looks the same.
> 
> This is not true. "ro" is not ignored:
> 
> # mount -t tmpfs
> tmpfs on /mnt (tmpfs, local)
> # mount -u -o ro /mnt
> mount: tmpfs: Operation not supported
> # mount -t tmpfs
> tmpfs on /mnt (tmpfs, local)
> # mount -u -o ro,export /mnt
> # mount -t tmpfs
> tmpfs on /mnt (tmpfs, local, read-only)
> 
> > It could be fixed with vfs_filteropt(9), not sure if this is worth doing here
> > though.
> 
> The problem with vfs_filteropt(9) is that it will allow some additional
> options (global_opts list in vfs_mount.c). However those options might
> already work sufficiently with update mount. Here is a mostly untested
> patch:
> 
> %%%
> Index: sys/fs/tmpfs/tmpfs_vfsops.c
> ===================================================================
> --- sys/fs/tmpfs/tmpfs_vfsops.c	(revision 230328)
> +++ sys/fs/tmpfs/tmpfs_vfsops.c	(working copy)
> @@ -82,6 +82,10 @@ static const char *tmpfs_opts[] = {
>  	NULL
>  };
>  
> +static const char *tmpfs_updateopts[] = {
> +	"from", "export", NULL
> +};
> +
>  /* --------------------------------------------------------------------- */
>  
>  static int
> @@ -150,12 +154,10 @@ tmpfs_mount(struct mount *mp)
>  		return (EINVAL);
>  
>  	if (mp->mnt_flag & MNT_UPDATE) {
> -		/*
> -		 * Only support update mounts for NFS export.
> -		 */
> -		if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
> -			return (0);
> -		return (EOPNOTSUPP);
> +		/* Only support update mounts for certain options. */
> +		if (vfs_filteropt(mp->mnt_optnew, tmpfs_updateopts) != 0)
> +			return (EOPNOTSUPP);
> +		return (0);
>  	}
>  
>  	vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
> %%%

Sorry for the late reply since I'm still off work for holidays
(Chinese New Year). I'll report back in a few weeks. If you 
have a patch, please commit it, thanks a lot!

	Kevin