7 files changed, 31 insertions, 2 deletions

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 8f9e26e91386..58c06bd58a96 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -472,6 +472,7 @@ static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c)
         if (err)
                 goto out_cleanup;
 
+        ovl_dentry_set_upper_alias(c->dentry);
         ovl_inode_update(d_inode(c->dentry), newdentry);
 out:
         dput(temp);
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index a072c27e03bc..8b2b23181b19 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -156,6 +156,7 @@ static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
                             struct dentry *newdentry, bool hardlink)
 {
         ovl_dentry_version_inc(dentry->d_parent);
+        ovl_dentry_set_upper_alias(dentry);
         if (!hardlink) {
                 ovl_inode_update(inode, newdentry);
                 ovl_copyattr(newdentry->d_inode, inode);
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index f7fb0c919419..2d8b6292fe21 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -674,7 +674,9 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
         memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
         dentry->d_fsdata = oe;
 
-        if (index && !upperdentry)
+        if (upperdentry)
+                ovl_dentry_set_upper_alias(dentry);
+        else if (index)
                 upperdentry = dget(index);
 
         if (upperdentry || ctr) {
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index f3e49cf34517..751b36a5c22f 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -206,6 +206,8 @@ void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
 bool ovl_dentry_is_opaque(struct dentry *dentry);
 bool ovl_dentry_is_whiteout(struct dentry *dentry);
 void ovl_dentry_set_opaque(struct dentry *dentry);
+bool ovl_dentry_has_upper_alias(struct dentry *dentry);
+void ovl_dentry_set_upper_alias(struct dentry *dentry);
 bool ovl_redirect_dir(struct super_block *sb);
 const char *ovl_dentry_get_redirect(struct dentry *dentry);
 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 9642ec64467b..878a750986dd 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -42,7 +42,10 @@ struct ovl_fs {
 /* private information held for every overlayfs dentry */
 struct ovl_entry {
         union {
-                bool opaque;
+                struct {
+                        unsigned long has_upper;
+                        bool opaque;
+                };
                 struct rcu_head rcu;
         };
         unsigned numlower;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 791581c370f5..f29ee08cf99f 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1119,6 +1119,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
         kfree(lowertmp);
 
         if (upperpath.dentry) {
+                oe->has_upper = true;
                 if (ovl_is_impuredir(upperpath.dentry))
                         ovl_set_flag(OVL_IMPURE, d_inode(root_dentry));
         }
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index c80b4bf1e64f..38fa75228c66 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -201,6 +201,25 @@ void ovl_dentry_set_opaque(struct dentry *dentry)
         oe->opaque = true;
 }
 
+/*
+ * For hard links it's possible for ovl_dentry_upper() to return positive, while
+ * there's no actual upper alias for the inode.  Copy up code needs to know
+ * about the existence of the upper alias, so it can't use ovl_dentry_upper().
+ */
+bool ovl_dentry_has_upper_alias(struct dentry *dentry)
+{
+        struct ovl_entry *oe = dentry->d_fsdata;
+
+        return oe->has_upper;
+}
+
+void ovl_dentry_set_upper_alias(struct dentry *dentry)
+{
+        struct ovl_entry *oe = dentry->d_fsdata;
+
+        oe->has_upper = true;
+}
+
 bool ovl_redirect_dir(struct super_block *sb)
 {
         struct ovl_fs *ofs = sb->s_fs_info;