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authorChuck Lever <chuck.lever@oracle.com>2022-03-31 22:30:10 +0300
committerChuck Lever <chuck.lever@oracle.com>2022-05-19 19:25:38 +0300
commit37324e6bb120bc3cb7cbaa87512ff3a93dbcf5c4 (patch)
tree34bacc7faeb7ad7e0eb5e7f960fe76b67c1f0c58
parent45cb7955c180a2a34d291e68938250c4f9bd294f (diff)
downloadlinux-37324e6bb120bc3cb7cbaa87512ff3a93dbcf5c4.tar.xz
SUNRPC: Cache deferral injection
Cache deferral injection stress-tests the cache deferral logic as well as upper layer protocol deferred request handlers. This facility is for developers and professional testers to ensure coverage of the rqst deferral code paths. To date, we haven't had an adequate way to ensure these code paths are covered during testing, short of temporary code changes to force their use. A file called /sys/kernel/debug/fail_sunrpc/ignore-cache-wait enables administrators to disable cache deferral injection while allowing other types of sunrpc errors to be injected. The default setting is that cache deferral injection is enabled (ignore=false). To enable support for cache deferral injection, CONFIG_FAULT_INJECTION, CONFIG_FAULT_INJECTION_DEBUG_FS, and CONFIG_SUNRPC_DEBUG must all be set to "Y". Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
-rw-r--r--net/sunrpc/cache.c18
-rw-r--r--net/sunrpc/debugfs.c3
-rw-r--r--net/sunrpc/fail.h2
3 files changed, 21 insertions, 2 deletions
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index bb1177395b99..c3c693b51c94 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -33,7 +33,9 @@
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include <trace/events/sunrpc.h>
+
#include "netns.h"
+#include "fail.h"
#define RPCDBG_FACILITY RPCDBG_CACHE
@@ -688,16 +690,30 @@ static void cache_limit_defers(void)
discard->revisit(discard, 1);
}
+#if IS_ENABLED(CONFIG_FAIL_SUNRPC)
+static inline bool cache_defer_immediately(void)
+{
+ return !fail_sunrpc.ignore_cache_wait &&
+ should_fail(&fail_sunrpc.attr, 1);
+}
+#else
+static inline bool cache_defer_immediately(void)
+{
+ return false;
+}
+#endif
+
/* Return true if and only if a deferred request is queued. */
static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
{
struct cache_deferred_req *dreq;
- if (req->thread_wait) {
+ if (!cache_defer_immediately()) {
cache_wait_req(req, item);
if (!test_bit(CACHE_PENDING, &item->flags))
return false;
}
+
dreq = req->defer(req);
if (dreq == NULL)
return false;
diff --git a/net/sunrpc/debugfs.c b/net/sunrpc/debugfs.c
index 7dc9cc929bfd..a176d5a0b0ee 100644
--- a/net/sunrpc/debugfs.c
+++ b/net/sunrpc/debugfs.c
@@ -262,6 +262,9 @@ static void fail_sunrpc_init(void)
debugfs_create_bool("ignore-server-disconnect", S_IFREG | 0600, dir,
&fail_sunrpc.ignore_server_disconnect);
+
+ debugfs_create_bool("ignore-cache-wait", S_IFREG | 0600, dir,
+ &fail_sunrpc.ignore_cache_wait);
}
#else
static void fail_sunrpc_init(void)
diff --git a/net/sunrpc/fail.h b/net/sunrpc/fail.h
index 69dc30cc44b8..4b4b500df428 100644
--- a/net/sunrpc/fail.h
+++ b/net/sunrpc/fail.h
@@ -14,8 +14,8 @@ struct fail_sunrpc_attr {
struct fault_attr attr;
bool ignore_client_disconnect;
-
bool ignore_server_disconnect;
+ bool ignore_cache_wait;
};
extern struct fail_sunrpc_attr fail_sunrpc;