Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs fixes from Miklos Szeredi:
 "Fix regressions:

   - missing CONFIG_EXPORTFS dependency

   - failure if upper fs doesn't support xattr

   - bad error cleanup

  This also adds the concept of "impure" directories complementing the
  "origin" marking introduced in -rc1. Together they enable getting
  consistent st_ino and d_ino for directory listings.

  And there's a bug fix and a cleanup as well"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: filter trusted xattr for non-admin
  ovl: mark upper merge dir with type origin entries "impure"
  ovl: mark upper dir with type origin entries "impure"
  ovl: remove unused arg from ovl_lookup_temp()
  ovl: handle rename when upper doesn't support xattr
  ovl: don't fail copy-up if upper doesn't support xattr
  ovl: check on mount time if upper fs supports setting xattr
  ovl: fix creds leak in copy up error path
  ovl: select EXPORTFS

1 files changed, 64 insertions, 8 deletions

diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index cfdea47313a1..809048913889 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -175,6 +175,13 @@ bool ovl_dentry_is_opaque(struct dentry *dentry)
 	return oe->opaque;
 }
 
+bool ovl_dentry_is_impure(struct dentry *dentry)
+{
+	struct ovl_entry *oe = dentry->d_fsdata;
+
+	return oe->impure;
+}
+
 bool ovl_dentry_is_whiteout(struct dentry *dentry)
 {
 	return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
@@ -191,14 +198,7 @@ bool ovl_redirect_dir(struct super_block *sb)
 {
 	struct ovl_fs *ofs = sb->s_fs_info;
 
-	return ofs->config.redirect_dir;
-}
-
-void ovl_clear_redirect_dir(struct super_block *sb)
-{
-	struct ovl_fs *ofs = sb->s_fs_info;
-
-	ofs->config.redirect_dir = false;
+	return ofs->config.redirect_dir && !ofs->noxattr;
 }
 
 const char *ovl_dentry_get_redirect(struct dentry *dentry)
@@ -303,3 +303,59 @@ void ovl_copy_up_end(struct dentry *dentry)
 	wake_up_locked(&ofs->copyup_wq);
 	spin_unlock(&ofs->copyup_wq.lock);
 }
+
+bool ovl_check_dir_xattr(struct dentry *dentry, const char *name)
+{
+	int res;
+	char val;
+
+	if (!d_is_dir(dentry))
+		return false;
+
+	res = vfs_getxattr(dentry, name, &val, 1);
+	if (res == 1 && val == 'y')
+		return true;
+
+	return false;
+}
+
+int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
+		       const char *name, const void *value, size_t size,
+		       int xerr)
+{
+	int err;
+	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+
+	if (ofs->noxattr)
+		return xerr;
+
+	err = ovl_do_setxattr(upperdentry, name, value, size, 0);
+
+	if (err == -EOPNOTSUPP) {
+		pr_warn("overlayfs: cannot set %s xattr on upper\n", name);
+		ofs->noxattr = true;
+		return xerr;
+	}
+
+	return err;
+}
+
+int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
+{
+	int err;
+	struct ovl_entry *oe = dentry->d_fsdata;
+
+	if (oe->impure)
+		return 0;
+
+	/*
+	 * Do not fail when upper doesn't support xattrs.
+	 * Upper inodes won't have origin nor redirect xattr anyway.
+	 */
+	err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE,
+				 "y", 1, 0);
+	if (!err)
+		oe->impure = true;
+
+	return err;
+}