[CRIU] [PATCH] early_init: Force to unlimit files on early init

[Cyrill Gorcunov]

From: Cyrill Gorcunov <gorcunov at virtuozzo.com>

It is so because when we checkpoint containers with huge number
of files opened we get

 | (00.659733) Error (criu/util.c:403): Can't open 57950: Too many open files
 | (00.659741) Error (criu/proc_parse.c:2399): Can't open 57950/task on procfs: Too many open files
 | (00.675635) Error (criu/cr-dump.c:2111): Dumping FAILED.
 | Failed to checkpoint the Container

simply because we're opening more files for criu itself. This mostly
reverts a148e87469a36dc75e263259e39ed30336343fc8

Signed-off-by: Cyrill Gorcunov <gorcunov at virtuozzo.com>
---
 criu/cr-restore.c | 32 --------------------------------
 criu/crtools.c    | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 32 deletions(-)

diff --git a/criu/cr-restore.c b/criu/cr-restore.c
index af2ca2921d00..a6cb8f1b3e07 100644
--- a/criu/cr-restore.c
+++ b/criu/cr-restore.c
@@ -2327,42 +2327,10 @@ int prepare_dummy_task_state(struct pstree_item *pi)
 	return 0;
 }
 
-static void rlimit_unlimit_nofile_self(void)
-{
-	struct rlimit new;
-
-	new.rlim_cur = kdat.sysctl_nr_open;
-	new.rlim_max = kdat.sysctl_nr_open;
-
-	if (prlimit(getpid(), RLIMIT_NOFILE, &new, NULL)) {
-		pr_perror("rlimir: Can't setup RLIMIT_NOFILE for self");
-		return;
-	} else
-		pr_debug("rlimit: RLIMIT_NOFILE unlimited for self\n");
-	service_fd_rlim_cur = kdat.sysctl_nr_open;
-}
-
 int cr_restore_tasks(void)
 {
 	int ret = -1;
 
-	/*
-	 * Service fd engine implies that file descriptors
-	 * used won't be borrowed by the rest of the code
-	 * and default 1024 limit is not enough for high
-	 * loaded test/containers. Thus use kdat engine
-	 * to fetch current system level limit for numbers
-	 * of files allowed to open up and lift up own
-	 * limits.
-	 *
-	 * Note we have to do it before the service fd
-	 * get inited and we dont exit with errors here
-	 * because in worst scenario where clash of fd
-	 * happen we simply exit with explicit error
-	 * during real action stage.
-	 */
-	rlimit_unlimit_nofile_self();
-
 	if (cr_plugin_init(CR_PLUGIN_STAGE__RESTORE))
 		return -1;
 
diff --git a/criu/crtools.c b/criu/crtools.c
index 3f64000c1e87..5da09beaa75f 100644
--- a/criu/crtools.c
+++ b/criu/crtools.c
@@ -51,8 +51,41 @@
 #include "sysctl.h"
 #include "img-remote.h"
 
+static void rlimit_unlimit_nofile_self(void)
+{
+	struct rlimit new;
+
+	new.rlim_cur = kdat.sysctl_nr_open;
+	new.rlim_max = kdat.sysctl_nr_open;
+
+	if (prlimit(getpid(), RLIMIT_NOFILE, &new, NULL)) {
+		pr_perror("rlimir: Can't setup RLIMIT_NOFILE for self");
+		return;
+	} else
+		pr_debug("rlimit: RLIMIT_NOFILE unlimited for self\n");
+	service_fd_rlim_cur = kdat.sysctl_nr_open;
+}
+
 static int early_init(void)
 {
+	/*
+	 * Service fd engine implies that file descritprs
+	 * used won't be borrowed by the rest of the code
+	 * and default 1024 limit is not enough for high
+	 * loaded test/containers. Thus use kdat engine
+	 * to fetch current system level limit for numbers
+	 * of files allowed to open up and lift up own
+	 * limits.
+	 *
+	 * Note we have to do it before the service fd
+	 * get inited and we dont exit with errors here
+	 * because in worst scenario where clash of fd
+	 * happen we simply exit with explicit error
+	 * during real action stage.
+	 */
+	if (!kerndat_files_stat(true))
+		rlimit_unlimit_nofile_self();
+
 	if (init_service_fd())
 		return 1;
 
-- 
2.20.1