Re: [PATCH 01/24] Unionfs: Documentation

[Christoph Hellwig]

On Mon, Jan 08, 2007 at 06:25:16PM -0500, Josef Sipek wrote:
> > There's no such problem with bind mounts.  It's surprising to see such a
> > restriction with union mounts.
> 
> Bind mounts are a purely VFS level construct. Unionfs is, as the name
> implies, a filesystem. Last year at OLS, it seemed that a lot of people
> agreed that unioning is neither purely a fs construct, nor purely a vfs
> construct.
> 
> I'm using Unionfs (and ecryptfs) as guinea pigs to make linux fs stacking
> friendly - a topic to be discussed at LSF in about a month.

And unionfs is the wrong thing do use for this.  Unioning is a complex
namespace operation and needs to be implemented in the VFS or at least
needs a lot of help from the VFS.  Getting namespace cache coherency
and especially locking right is imposisble with out that.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/