--- zzzz-none-000/linux-3.10.107/fs/cachefiles/xattr.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/fs/cachefiles/xattr.c	2021-02-04 17:41:59.000000000 +0000
@@ -33,7 +33,7 @@
 	int ret;
 
 	ASSERT(dentry);
-	ASSERT(dentry->d_inode);
+	ASSERT(d_backing_inode(dentry));
 
 	if (!object->fscache.cookie)
 		strcpy(type, "C3");
@@ -51,9 +51,8 @@
 	}
 
 	if (ret != -EEXIST) {
-		kerror("Can't set xattr on %*.*s [%lu] (err %d)",
-		       dentry->d_name.len, dentry->d_name.len,
-		       dentry->d_name.name, dentry->d_inode->i_ino,
+		pr_err("Can't set xattr on %pd [%lu] (err %d)\n",
+		       dentry, d_backing_inode(dentry)->i_ino,
 		       -ret);
 		goto error;
 	}
@@ -64,9 +63,8 @@
 		if (ret == -ERANGE)
 			goto bad_type_length;
 
-		kerror("Can't read xattr on %*.*s [%lu] (err %d)",
-		       dentry->d_name.len, dentry->d_name.len,
-		       dentry->d_name.name, dentry->d_inode->i_ino,
+		pr_err("Can't read xattr on %pd [%lu] (err %d)\n",
+		       dentry, d_backing_inode(dentry)->i_ino,
 		       -ret);
 		goto error;
 	}
@@ -85,16 +83,15 @@
 	return ret;
 
 bad_type_length:
-	kerror("Cache object %lu type xattr length incorrect",
-	       dentry->d_inode->i_ino);
+	pr_err("Cache object %lu type xattr length incorrect\n",
+	       d_backing_inode(dentry)->i_ino);
 	ret = -EIO;
 	goto error;
 
 bad_type:
 	xtype[2] = 0;
-	kerror("Cache object %*.*s [%lu] type %s not %s",
-	       dentry->d_name.len, dentry->d_name.len,
-	       dentry->d_name.name, dentry->d_inode->i_ino,
+	pr_err("Cache object %pd [%lu] type %s not %s\n",
+	       dentry, d_backing_inode(dentry)->i_ino,
 	       xtype, type);
 	ret = -EIO;
 	goto error;
@@ -109,13 +106,12 @@
 	struct dentry *dentry = object->dentry;
 	int ret;
 
-	ASSERT(object->fscache.cookie);
 	ASSERT(dentry);
 
 	_enter("%p,#%d", object, auxdata->len);
 
 	/* attempt to install the cache metadata directly */
-	_debug("SET %s #%u", object->fscache.cookie->def->name, auxdata->len);
+	_debug("SET #%u", auxdata->len);
 
 	ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
 			   &auxdata->type, auxdata->len,
@@ -138,13 +134,12 @@
 	struct dentry *dentry = object->dentry;
 	int ret;
 
-	ASSERT(object->fscache.cookie);
 	ASSERT(dentry);
 
 	_enter("%p,#%d", object, auxdata->len);
 
 	/* attempt to install the cache metadata directly */
-	_debug("SET %s #%u", object->fscache.cookie->def->name, auxdata->len);
+	_debug("SET #%u", auxdata->len);
 
 	ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
 			   &auxdata->type, auxdata->len,
@@ -159,6 +154,43 @@
 }
 
 /*
+ * check the consistency between the backing cache and the FS-Cache cookie
+ */
+int cachefiles_check_auxdata(struct cachefiles_object *object)
+{
+	struct cachefiles_xattr *auxbuf;
+	enum fscache_checkaux validity;
+	struct dentry *dentry = object->dentry;
+	ssize_t xlen;
+	int ret;
+
+	ASSERT(dentry);
+	ASSERT(d_backing_inode(dentry));
+	ASSERT(object->fscache.cookie->def->check_aux);
+
+	auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL);
+	if (!auxbuf)
+		return -ENOMEM;
+
+	xlen = vfs_getxattr(dentry, cachefiles_xattr_cache,
+			    &auxbuf->type, 512 + 1);
+	ret = -ESTALE;
+	if (xlen < 1 ||
+	    auxbuf->type != object->fscache.cookie->def->type)
+		goto error;
+
+	xlen--;
+	validity = fscache_check_aux(&object->fscache, &auxbuf->data, xlen);
+	if (validity != FSCACHE_CHECKAUX_OKAY)
+		goto error;
+
+	ret = 0;
+error:
+	kfree(auxbuf);
+	return ret;
+}
+
+/*
  * check the state xattr on a cache file
  * - return -ESTALE if the object should be deleted
  */
@@ -172,7 +204,7 @@
 	_enter("%p,#%d", object, auxdata->len);
 
 	ASSERT(dentry);
-	ASSERT(dentry->d_inode);
+	ASSERT(d_backing_inode(dentry));
 
 	auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, cachefiles_gfp);
 	if (!auxbuf) {
@@ -193,7 +225,7 @@
 
 		cachefiles_io_error_obj(object,
 					"Can't read xattr on %lu (err %d)",
-					dentry->d_inode->i_ino, -ret);
+					d_backing_inode(dentry)->i_ino, -ret);
 		goto error;
 	}
 
@@ -244,7 +276,7 @@
 			cachefiles_io_error_obj(object,
 						"Can't update xattr on %lu"
 						" (error %d)",
-						dentry->d_inode->i_ino, -ret);
+						d_backing_inode(dentry)->i_ino, -ret);
 			goto error;
 		}
 	}
@@ -258,8 +290,8 @@
 	return ret;
 
 bad_type_length:
-	kerror("Cache object %lu xattr length incorrect",
-	       dentry->d_inode->i_ino);
+	pr_err("Cache object %lu xattr length incorrect\n",
+	       d_backing_inode(dentry)->i_ino);
 	ret = -EIO;
 	goto error;
 
@@ -284,7 +316,7 @@
 			cachefiles_io_error(cache,
 					    "Can't remove xattr from %lu"
 					    " (error %d)",
-					    dentry->d_inode->i_ino, -ret);
+					    d_backing_inode(dentry)->i_ino, -ret);
 	}
 
 	_leave(" = %d", ret);