Re: [NFS] [PATH 10/19] xfs: new export ops

[Greg Banks <gnb@sgi.com>]

On Thu, Aug 30, 2007 at 03:16:41PM +0200, Christoph Hellwig wrote:
> -#if XFS_BIG_INUMS
>  	bhv_vfs_t		*vfs = vfs_from_sb(inode->i_sb);
>  
> -	if (!(vfs->vfs_flag & VFS_32BITINODES)) {
> -		/* filesystem may contain 64bit inode numbers */
> -		is64 = XFS_FILEID_TYPE_64FLAG;
> -	}
> -#endif
>  
>  	/* Directories don't need their parent encoded, they have ".." */
>  	if (S_ISDIR(inode->i_mode))
> -	    connectable = 0;
> +		fileid_type = FILEID_INO32_GEN;
> +	else
> +		fileid_type = FILEID_INO32_GEN_PARENT;
> +
> +	/* filesystem may contain 64bit inode numbers */
> +	if (!(vfs->vfs_flag & VFS_32BITINODES))
> +		fileid_type |= XFS_FILEID_TYPE_64FLAG;

Not really a comment on your patches, but I got the original logic
wrong here.  The VFS_32BITINODES flag only affects newly allocated
inodes and is no guarantee that any particular inode is < 2^32-1.
It's possible for an unlucky user to perform a sequence of mounts
and IO which results in large inode numbers despite the presence of
that flag; we recently saw this happen by accident on a customer site.
So the right thing to do is probably to check the inode number against
(u32)~0.  Unfortunately, given the current encoding scheme, you have to
check both the inode and the parent inode, which complicates the logic.

Greg.
-- 
Greg Banks, R&D Software Engineer, SGI Australian Software Group.
Apparently, I'm Bedevere.  Which MPHG character are you?
I don't speak for SGI.