fault: add ability to fault open_by_handel in check_open_handle

From code coverage report, we found that inotify_irmap doesn't test irmap
cache, because we is always able to resolve path from /proc/PID/fd/X.

Current view:	top level - criu - irmap.c (source / functions)			Hit	Total	Coverage
Test:	criu.info		Lines:	40	223	17.9 %
Date:	2016-03-16		Functions:	4	13	30.8 %

This series introduces a new fault to emulate a situation
when a file can't be opened by handle and we have to find
it in the irmap cache/

It's required to test irmap cache. I don't know how to force it
without this patch. Each time when a file can be opened by handle,
its path can be resolved via /proc/PID/fd/X.
Signed-off-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/fsnotify.c

@@ -40,6 +40,7 @@
 #include "cr_options.h"
 #include "namespaces.h"
 #include "pstree.h"
+#include "fault-injection.h"
 
 #include "protobuf.h"
 #include "images/fsnotify.pb-c.h"
@@ -224,7 +225,13 @@ int check_open_handle(unsigned int s_dev, unsigned long i_ino,
 	int fd = -1;
 	char *path;
 
+	if (fault_injected(FI_CHECK_OPEN_HANDLE)) {
+		fd = -1;
+		goto fault;
+	}
+
 	fd = open_handle(s_dev, i_ino, f_handle);
+fault:
 	if (fd >= 0) {
 		struct mount_info *mi;
 

criu/include/fault-injection.h

@@ -6,6 +6,8 @@ enum faults {
 	FI_NONE = 0,
 	FI_DUMP_EARLY,
 	FI_RESTORE_ROOT_ONLY,
+	/* not fatal */
+	FI_CHECK_OPEN_HANDLE = 128,
 	FI_MAX,
 };
 

test/jenkins/criu-fault.sh

@@ -4,3 +4,4 @@ source `dirname $0`/criu-lib.sh
 prep
 ./test/zdtm.py run -t zdtm/static/env00 --fault 1 --report report -f h || fail
 ./test/zdtm.py run -t zdtm/static/unlink_fstat00 --fault 2 --report report -f h || fail
+./test/zdtm.py run -t zdtm/static/inotify_irmap --fault 128  --pre 2 -f uns || fail

test/zdtm.py

@@ -678,7 +678,7 @@ class criu_cli:
 		ret = self.__criu(action, s_args, self.__fault, strace, preexec)
 		grep_errors(os.path.join(__ddir, log))
 		if ret != 0:
-			if self.__fault:
+			if self.__fault and int(self.__fault) < 128:
 				try_run_hook(self.__test, ["--fault", action])
 				if action == "dump":
 					# create a clean directory for images