1 files changed, 33 insertions, 4 deletions

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index bfabc65fdc74..0c5e79966957 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -150,12 +150,39 @@ static int ovl_dir_getattr(const struct path *path, struct kstat *stat,
         type = ovl_path_real(dentry, &realpath);
         old_cred = ovl_override_creds(dentry->d_sb);
         err = vfs_getattr(&realpath, stat, request_mask, flags);
-        revert_creds(old_cred);
         if (err)
-                return err;
+                goto out;
+
+        /*
+         * When all layers are on the same fs, use the copy-up-origin st_ino,
+         * which is persistent, unique and constant across copy up.
+         *
+         * Otherwise the pair {real st_ino; overlay st_dev} is not unique, so
+         * use the non persistent overlay st_ino.
+         */
+        if (ovl_same_sb(dentry->d_sb)) {
+                if (OVL_TYPE_ORIGIN(type)) {
+                        struct kstat lowerstat;
+
+                        ovl_path_lower(dentry, &realpath);
+                        err = vfs_getattr(&realpath, &lowerstat,
+                                          STATX_INO, flags);
+                        if (err)
+                                goto out;
+
+                        WARN_ON_ONCE(stat->dev != lowerstat.dev);
+                        stat->ino = lowerstat.ino;
+                }
+        } else {
+                stat->ino = dentry->d_inode->i_ino;
+        }
 
+        /*
+         * Always use the overlay st_dev for directories, so 'find -xdev' will
+         * scan the entire overlay mount and won't cross the overlay mount
+         * boundaries.
+         */
         stat->dev = dentry->d_sb->s_dev;
-        stat->ino = dentry->d_inode->i_ino;
 
         /*
          * It's probably not worth it to count subdirs to get the
@@ -164,8 +191,10 @@ static int ovl_dir_getattr(const struct path *path, struct kstat *stat,
          */
         if (OVL_TYPE_MERGE(type))
                 stat->nlink = 1;
+out:
+        revert_creds(old_cred);
 
-        return 0;
+        return err;
 }
 
 /* Common operations required to be done after creation of file on upper */