Commit 1fc31aac authored May 27, 2021 by Vyacheslav Yurkov Committed by Miklos Szeredi Aug 17, 2021

ovl: do not set overlay.opaque for new directories



Enable optimizations only if user opted-in for any of extended features.
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@bruker.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

parent ca45275c

fs/overlayfs/dir.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -321,6 +321,7 @@ 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;
		@@ -339,7 +340,8 @@ 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);
		}