On Thu, May 27, 2021 at 5:06 PM Vyacheslav Yurkov <uvv.mail@xxxxxxxxx> wrote:
>
> From: Vyacheslav Yurkov <Vyacheslav.Yurkov@xxxxxxxxxx>
>
> Disable optimizations if user opted-in for any of extended features.
The code is correct. The comment is negated.
Your setup is a default setup - you did NOT opt-in to any new feature.
Only in setups like those we disable the optimization.
Thanks,
Amir.
> If optimization is enabled, it breaks existing use case when a lower layer
> directory appears after directory was created on a merged layer. If
> overlay.opaque is applied, new files on lower layer are not visible.
>
> Consider the following scenario:
> - /lower and /upper are mounted to /merged
> - directory /merged/new-dir is created with a file test1
> - overlay is unmounted
> - directory /lower/new-dir is created with a file test2
> - overlay is mounted again
>
> If opaque is applied by default, file test2 is not going to be visible
> without explicitly clearing the overlay.opaque attribute
>
> Signed-off-by: Vyacheslav Yurkov <Vyacheslav.Yurkov@xxxxxxxxxx>
> ---
> fs/overlayfs/dir.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
> index 93efe7048a77..03a22954fe61 100644
> --- a/fs/overlayfs/dir.c
> +++ b/fs/overlayfs/dir.c
> @@ -320,6 +320,7 @@ static bool ovl_type_origin(struct dentry *dentry)
> static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
> struct ovl_cattr *attr)
> {
> + struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
> struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
> struct inode *udir = upperdir->d_inode;
> struct dentry *newdentry;
> @@ -338,7 +339,8 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
> if (IS_ERR(newdentry))
> goto out_unlock;
>
> - if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry)) {
> + if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry) &&
> + !ovl_allow_offline_changes(ofs)) {
> /* Setting opaque here is just an optimization, allow to fail */
> ovl_set_opaque(dentry, newdentry);
> }
> --
> 2.25.1
>
