On Thu, Nov 9, 2017 at 10:50 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> By default metadata only copy up is disabled. Provide a mount option so
> that users can choose one way or other.
>
> Also provide a kernel config and module option to enable/disable
> metacopy feature.
>
> Like index feature, we verify on mount that upper root is not being
> reused with a different lower root. This hopes to get the configuration
> right and detect the copied layers use case. But this does only so
> much as we don't verify all the lowers. So it is possible that a lower is
> missing and later data copy up fails.
>
> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Fine, as long as Miklos agrees not to enforce exclusive dir lock,
it's fine by me.
Please take a look at my ovl-features patches and say what you think.
It is time we started to enforce some order with all the inter-dependencies
between features.
With my proposal, it will make mounting an overlay with metacopy object
on older kernel slightly harder (but not impossible), so it can help admins
from tripping over themselves.
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
[...]
> - if (ofs->config.index && !ovl_can_decode_fh(path->dentry->d_sb)) {
> + if ((ofs->config.index || ofs->config.metacopy) &&
> + !ovl_can_decode_fh(path->dentry->d_sb)) {
> + if (ofs->config.index)
> + pr_warn("overlayfs: fs on '%s' does not support file handles, falling back to index=off.\n", name);
> +
> + if (ofs->config.metacopy)
> + pr_warn("overlayfs: fs on '%s' does not support file handles, falling back to metacopy=off.\n", name);
> +
> ofs->config.index = false;
> - pr_warn("overlayfs: fs on '%s' does not support file handles, falling back to index=off.\n", name);
> + ofs->config.metacopy = false;
> }
>
So you didn't like the less granular but shorter warning I used in my
verify_dir patches, e.g.:
ofs->config.index = false;
- pr_warn("overlayfs: fs on '%s' does not support file
handles, falling back to index=off.\n", name);
+ ofs->config.metacopy = false;
+ pr_warn("overlayfs: fs on '%s' does not support file
handles, falling back to index=off,metacopy=off.\n", name);
Doesn't matter much to me,
Amir.
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