@@ -19,3 +19,10 @@ config CACHEFILES_DEBUG
caching on files module. If this is set, the debugging output may be
enabled by setting bits in /sys/modules/cachefiles/parameter/debug or
by including a debugging specifier in /etc/cachefilesd.conf.
+
+config CACHEFILES_ERROR_INJECTION
+ bool "Provide error injection for cachefiles"
+ depends on CACHEFILES && SYSCTL
+ help
+ This permits error injection to be enabled in cachefiles whilst a
+ cache is in service.
@@ -6,4 +6,6 @@
cachefiles-y := \
main.o
+cachefiles-$(CONFIG_CACHEFILES_ERROR_INJECTION) += error_inject.o
+
obj-$(CONFIG_CACHEFILES) := cachefiles.o
new file mode 100644
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Error injection handling.
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/sysctl.h>
+#include "internal.h"
+
+unsigned int cachefiles_error_injection_state;
+
+static struct ctl_table_header *cachefiles_sysctl;
+static struct ctl_table cachefiles_sysctls[] = {
+ {
+ .procname = "error_injection",
+ .data = &cachefiles_error_injection_state,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = proc_douintvec,
+ },
+ {}
+};
+
+static struct ctl_table cachefiles_sysctls_root[] = {
+ {
+ .procname = "cachefiles",
+ .mode = 0555,
+ .child = cachefiles_sysctls,
+ },
+ {}
+};
+
+int __init cachefiles_register_error_injection(void)
+{
+ cachefiles_sysctl = register_sysctl_table(cachefiles_sysctls_root);
+ if (!cachefiles_sysctl)
+ return -ENOMEM;
+ return 0;
+
+}
+
+void cachefiles_unregister_error_injection(void)
+{
+ unregister_sysctl_table(cachefiles_sysctl);
+}
@@ -24,6 +24,45 @@ extern unsigned cachefiles_debug;
#define CACHEFILES_DEBUG_KLEAVE 2
#define CACHEFILES_DEBUG_KDEBUG 4
+/*
+ * error_inject.c
+ */
+#ifdef CONFIG_CACHEFILES_ERROR_INJECTION
+extern unsigned int cachefiles_error_injection_state;
+extern int cachefiles_register_error_injection(void);
+extern void cachefiles_unregister_error_injection(void);
+
+#else
+#define cachefiles_error_injection_state 0
+
+static inline int cachefiles_register_error_injection(void)
+{
+ return 0;
+}
+
+static inline void cachefiles_unregister_error_injection(void)
+{
+}
+#endif
+
+
+static inline int cachefiles_inject_read_error(void)
+{
+ return cachefiles_error_injection_state & 2 ? -EIO : 0;
+}
+
+static inline int cachefiles_inject_write_error(void)
+{
+ return cachefiles_error_injection_state & 2 ? -EIO :
+ cachefiles_error_injection_state & 1 ? -ENOSPC :
+ 0;
+}
+
+static inline int cachefiles_inject_remove_error(void)
+{
+ return cachefiles_error_injection_state & 2 ? -EIO : 0;
+}
+
/*
* debug tracing
@@ -36,8 +36,18 @@ MODULE_LICENSE("GPL");
*/
static int __init cachefiles_init(void)
{
+ int ret;
+
+ ret = cachefiles_register_error_injection();
+ if (ret < 0)
+ goto error_einj;
+
pr_info("Loaded\n");
return 0;
+
+error_einj:
+ pr_err("failed to register: %d\n", ret);
+ return ret;
}
fs_initcall(cachefiles_init);
@@ -48,6 +58,8 @@ fs_initcall(cachefiles_init);
static void __exit cachefiles_exit(void)
{
pr_info("Unloading\n");
+
+ cachefiles_unregister_error_injection();
}
module_exit(cachefiles_exit);
Add support for injecting ENOSPC or EIO errors. This needs to be enabled by CONFIG_CACHEFILES_ERROR_INJECTION=y. Once enabled, ENOSPC on things like write and mkdir can be triggered by: echo 1 >/proc/sys/cachefiles/error_injection and EIO can be triggered on most operations by: echo 2 >/proc/sys/cachefiles/error_injection Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-cachefs@redhat.com --- fs/cachefiles/Kconfig | 7 ++++++ fs/cachefiles/Makefile | 2 ++ fs/cachefiles/error_inject.c | 46 ++++++++++++++++++++++++++++++++++++++++++ fs/cachefiles/internal.h | 39 ++++++++++++++++++++++++++++++++++++ fs/cachefiles/main.c | 12 +++++++++++ 5 files changed, 106 insertions(+) create mode 100644 fs/cachefiles/error_inject.c