[PATCH v3 19/19] ovl: support idmapped layers

[Christian Brauner <brauner@kernel.org>]

Now that overlay is able to take a layers idmapping into account allow
overlay mounts to be created on top of idmapped mounts.

Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
---
/* v2 */
- Turn on support for idmapped mounts in ovl_upper_idmap() helper here
  after we've introduced it earlier in the series and made it return the
  initial idmapping.

/* v3 */
unchanged
---
 fs/overlayfs/ovl_entry.h | 2 +-
 fs/overlayfs/super.c     | 4 ----
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 79b612cfbe52..898b002a5c6f 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -92,7 +92,7 @@ static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs)
 
 static inline struct user_namespace *ovl_upper_idmap(struct ovl_fs *ofs)
 {
-       return &init_user_ns;
+	return mnt_user_ns(ovl_upper_mnt(ofs));
 }
 
 static inline struct ovl_fs *OVL_FS(struct super_block *sb)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 9a656a24f7b1..d4cc07f7a2ef 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -874,10 +874,6 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path)
 		pr_err("filesystem on '%s' not supported\n", name);
 		goto out_put;
 	}
-	if (is_idmapped_mnt(path->mnt)) {
-		pr_err("idmapped layers are currently not supported\n");
-		goto out_put;
-	}
 	if (!d_is_dir(path->dentry)) {
 		pr_err("'%s' not a directory\n", name);
 		goto out_put;
-- 
2.32.0