On Tue, Mar 6, 2018 at 10:54 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> Right now we rely on path based lookup for data origin of metacopy upper.
> This will work only if upper has not been renamed. We solved this problem
> already for merged directories using redirect. Use same logic for metacopy
> files.
>
> This patch just goes on to check redirects for metacopy files.
>
> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
> ---
> fs/overlayfs/namei.c | 17 ++++++++---------
> 1 file changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
> index 220e754c974b..a4a5c5f5540d 100644
> --- a/fs/overlayfs/namei.c
> +++ b/fs/overlayfs/namei.c
> @@ -265,22 +265,22 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
> goto put_and_out;
> }
> if (!d_can_lookup(this)) {
> - if (d->is_dir)
> - goto put_and_out;
> + d->is_dir = false;
That test was supposed to catch non-dir under dir from an upper layer
but you are loosing the information stored in d->dir.
> err = ovl_check_metacopy_xattr(this);
> if (err < 0)
> goto out_err;
> if (!err) {
> d->stop = true;
> d->metacopy = false;
> + goto out;
> } else
> d->metacopy = true;
> - goto out;
> - }
> - d->is_dir = true;
> - if (!d->last && ovl_is_opaquedir(this)) {
> - d->stop = d->opaque = true;
> - goto out;
> + } else {
> + d->is_dir = true;
> + if (!d->last && ovl_is_opaquedir(this)) {
> + d->stop = d->opaque = true;
> + goto out;
I think there is a bug here - not related to your change, but semi related
to your recent fix patch (patch 1 in this series).
d->last is set to true when lookup in parent poe->numlower layer,
but parent may be pure upper for example and redirect from child can still
continue lookup to lower layers. If a directory is marked both "redirect" and
"opaque" (which is an inconsistency). In that case, d->last will be true
and opaque xattr will not be checked, but redirect will be checked.
Since AFAIK d->last is an optimization, I think it could be relaxed to
lower.layer->idx == roe->numlower - 1
and then for the d->last case, we can skip both opaque and redirect checks
and skip redirect check for both directory and metadata.
> + }
> }
> err = ovl_check_redirect(this, d, prelen, post);
> if (err)
Thanks,
Amir.
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