Re: [RFC][PATCH 2/5] introduce simple_set_mnt_no_get() helper for NFS

[Trond Myklebust <trond.myklebust@fys.uio.no>]

On Tue, 2008-04-29 at 11:59 -0700, Dave Hansen wrote:
> The next patch will introduce a list of all mounts for a given
> superblock.  In order to keep the list, we need to make sure
> all filesystems attaching a mount to a superblock get added
> to this list.
> 
> NFS currently bypasses the simple_set_mnt() function, and sets
> mnt_sb directly.  This patch makes it use a helper function,
> instead.
> 
> Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
> ---
> 
>  linux-2.6.git-dave/fs/namespace.c     |   11 +++++++++--
>  linux-2.6.git-dave/fs/nfs/super.c     |   10 +++++-----
>  linux-2.6.git-dave/include/linux/fs.h |    1 +
>  3 files changed, 15 insertions(+), 7 deletions(-)
> 
> diff -puN fs/namespace.c~introduce_simple_set_mnt_no_get_helper_for_NFS fs/namespace.c
> --- linux-2.6.git/fs/namespace.c~introduce_simple_set_mnt_no_get_helper_for_NFS	2008-04-29 11:56:39.000000000 -0700
> +++ linux-2.6.git-dave/fs/namespace.c	2008-04-29 11:56:39.000000000 -0700
> @@ -402,12 +402,19 @@ static void __mnt_unmake_readonly(struct
>  	spin_unlock(&vfsmount_lock);
>  }
>  
> -int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
> +int simple_set_mnt_no_get(struct vfsmount *mnt, struct super_block *sb)
>  {
>  	mnt->mnt_sb = sb;
> -	mnt->mnt_root = dget(sb->s_root);
> +	add_mount_to_sb_list(mnt, sb);
>  	return 0;
>  }
> +EXPORT_SYMBOL(simple_set_mnt_no_get);
> +
> +int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
> +{
> +	mnt->mnt_root = dget(sb->s_root);
> +	return simple_set_mnt_no_get(mnt, sb);
> +}
>  

My only concern is the proliferation of 'simple_*' operations: in some
cases in libfs.c we explicitly label those as being for in-memory/ramfs
filesystems, whereas in other cases (such as this one) the name appears
to be used for more generic functions.

Cheers
  Trond