On Wed, Dec 20, 2023 at 1:56 AM Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> Hi all,
>
> Today's linux-next merge of the vfs tree got a conflict in:
>
> fs/overlayfs/copy_up.c
>
> between commit:
>
> 413ba91089c7 ("ovl: fix dentry reference leak after changes to underlying layers")
>
> from the overlayfs-fixes tree and commit:
>
> a8b0026847b8 ("rename(): avoid a deadlock in the case of parents having no common ancestor")
>
> from the vfs tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging. You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
>
You solved it correctly, but anyway, ovl-fixes is for v6.7-rc7 and I plan
to send a PR for it soon.
I did try to give Al a heads up:
https://lore.kernel.org/linux-unionfs/CAOQ4uxi+4-jyNY6jzNt1wG5xcYSZiSfU0AtCWtF71PSW160zRw@xxxxxxxxxxxxxx/
Thanks,
Amir.
>
> diff --cc fs/overlayfs/copy_up.c
> index 696478f09cc1,e44dc5f66161..000000000000
> --- a/fs/overlayfs/copy_up.c
> +++ b/fs/overlayfs/copy_up.c
> @@@ -779,13 -757,14 +779,15 @@@ static int ovl_copy_up_workdir(struct o
> * lock ordering with sb_writers, which shouldn't be held when calling
> * ovl_copy_up_data(), so lock workdir and destdir and make sure that
> * temp wasn't moved before copy up completion or cleanup.
> - * If temp was moved, abort without the cleanup.
> */
> ovl_start_write(c->dentry);
> - if (lock_rename(c->workdir, c->destdir) != NULL ||
> - temp->d_parent != c->workdir) {
> + trap = lock_rename(c->workdir, c->destdir);
> + if (trap || temp->d_parent != c->workdir) {
> + /* temp or workdir moved underneath us? abort without cleanup */
> + dput(temp);
> err = -EIO;
> + if (IS_ERR(trap))
> + goto out;
> goto unlock;
> } else if (err) {
> goto cleanup;
