client: Add config option to inject sleep for tick

Testing the tick delay with a fork/suspend is causing
corruption in the lockdep code.  This approach uses
a config option to sleep the tick thread for a number
of seconds, avoiding the entire fork/suspend mess.

Signed-off-by: Sam Lang <sam.lang@inktank.com>

3 files changed, 9 insertions, 48 deletions

diff --git a/src/client/Client.cc b/src/client/Client.cc
index 0ca174b4536..d876454f0f4 100644
--- a/src/client/Client.cc
+++ b/src/client/Client.cc
@@ -3656,6 +3656,12 @@ void Client::flush_cap_releases()
 
 void Client::tick()
 {
+  if (cct->_conf->client_debug_inject_tick_delay > 0) {
+    sleep(cct->_conf->client_debug_inject_tick_delay);
+    assert(0 == cct->_conf->set_val("client_debug_inject_tick_delay", "0"));
+    cct->_conf->apply_changes(NULL);
+  }
+
   ldout(cct, 21) << "tick" << dendl;
   tick_event = new C_C_Tick(this);
   timer.add_event_after(cct->_conf->client_tick_interval, tick_event);
diff --git a/src/common/config_opts.h b/src/common/config_opts.h
index b9e317b82dc..bd5b733bd64 100644
--- a/src/common/config_opts.h
+++ b/src/common/config_opts.h
@@ -183,6 +183,7 @@ OPTION(client_oc_target_dirty, OPT_INT, 1024*1024* 8) // target dirty (keep this
 OPTION(client_oc_max_dirty_age, OPT_DOUBLE, 5.0)      // max age in cache before writeback
 OPTION(client_oc_max_objects, OPT_INT, 1000)      // max objects in cache
 OPTION(client_debug_force_sync_read, OPT_BOOL, false)     // always read synchronously (go to osds)
+OPTION(client_debug_inject_tick_delay, OPT_INT, 0) // delay the client tick for a number of seconds
 // note: the max amount of "in flight" dirty data is roughly (max - target)
 OPTION(fuse_use_invalidate_cb, OPT_BOOL, false) // use fuse 2.8+ invalidate callback to keep page cache consistent
 OPTION(fuse_big_writes, OPT_BOOL, true)
diff --git a/src/test/libcephfs/caps.cc b/src/test/libcephfs/caps.cc
index 5a421ea410c..96f1a90024d 100644
--- a/src/test/libcephfs/caps.cc
+++ b/src/test/libcephfs/caps.cc
@@ -26,60 +26,14 @@
 #include <sys/xattr.h>
 #include <signal.h>
 
-void do_sigusr1(int s) {}
-
-// wait_and_suspend() forks the process, waits for the
-// child to signal SIGUSR1, suspends the child with SIGSTOP
-// sleeps for s seconds, and then unsuspends the child,
-// waits for the child to exit, and then returns the exit code
-// of the child
-static int _wait_and_suspend(int s) {
-
-  int fpid = fork();
-  if (fpid != 0) {
-    // wait for child to signal
-    signal(SIGUSR1, &do_sigusr1);
-    sigset_t set;
-    sigaddset(&set, SIGUSR1);
-    int sig;
-    sigwait(&set, &sig);
-
-    // fork and suspend child, sleep for 20 secs, and resume
-    kill(fpid, SIGSTOP);
-    sleep(s);
-    kill(fpid, SIGCONT);
-    int status;
-    wait(&status);
-    if (WIFEXITED(status))
-      return WEXITSTATUS(status);
-    return 1;
-  }
-  return -1;
-}
-
-// signal_for_suspend sends the parent the SIGUSR1 signal
-// and sleeps for 1 second so that it can be suspended at the
-// point of the call
-static void _signal_for_suspend() {
-  kill(getppid(), SIGUSR1);
-}
-
 TEST(Caps, ReadZero) {
 
-  int w = _wait_and_suspend(20);
-  if (w >= 0) {
-    ASSERT_EQ(0, w);
-    return;
-  }
-
-  pid_t mypid = getpid();
+  int mypid = getpid();
   struct ceph_mount_info *cmount;
   ASSERT_EQ(0, ceph_create(&cmount, NULL));
   ASSERT_EQ(0, ceph_conf_read_file(cmount, NULL));
   ASSERT_EQ(0, ceph_mount(cmount, "/"));
 
-  ASSERT_EQ(0, ceph_conf_set(cmount, "client_cache_size", "10"));
-
   int i = 0;
   for(; i < 30; ++i) {
 
@@ -114,7 +68,7 @@ TEST(Caps, ReadZero) {
     ASSERT_EQ(expect, caps & expect);
   }
 
-  _signal_for_suspend();
+  ASSERT_EQ(0, ceph_conf_set(cmount, "client_debug_inject_tick_delay", "20"));
 
   for(i = 0; i < 30; ++i) {