Re: [RFC 11/26] tmpfs white-out support

From: Hugh Dickins
Date: Wed Aug 01 2007 - 11:14:59 EST


On Mon, 30 Jul 2007, Jan Blunck wrote:

> Introduce white-out support to tmpfs.
>
> Signed-off-by: Jan Blunck <jblunck@xxxxxxx>
> ---
> include/linux/shmem_fs.h | 1
> mm/shmem.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 55 insertions(+)

I see there's debate about whether this (and its fellows) give the
right semantic to whiteouts; and I've not begun to think about that.

But as a patch to tmpfs for what you're trying to do, it looks just
about fine. I say "just about" because the reference counting looks
right, but I wouldn't dare say that it _is_ right without testing.

And I'd probably want to add a minor adjustment, so that a mount with
nr_inodes=1000 could still support exactly 1000 inodes, despite your
allocating one for the whiteout (usually never used) at mount time.
But that can follow along later, no problem.

Hugh
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