From e4755bfa2c4e1af1e71cc5b4031bab0275a929b4 Mon Sep 17 00:00:00 2001
From: Ramon Nou <ramon.nou@bsc.es>
Date: Mon, 4 Nov 2024 15:09:51 +0100
Subject: [PATCH 1/2] Adding pthread_atfork to syscall

---
 include/client/preload.hpp |  7 +++++++
 src/client/preload.cpp     | 29 ++++++++++++++++++++++++++++-
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/include/client/preload.hpp b/include/client/preload.hpp
index afad97c68..ffc3e942d 100644
--- a/include/client/preload.hpp
+++ b/include/client/preload.hpp
@@ -49,4 +49,11 @@ void
 destroy_preload() __attribute__((destructor));
 #endif
 
+void
+at_fork_syscall();
+void
+at_child_syscall();
+void
+at_parent_syscall();
+
 #endif // IOINTERCEPT_PRELOAD_HPP
diff --git a/src/client/preload.cpp b/src/client/preload.cpp
index 67926fbb3..6bf27d964 100644
--- a/src/client/preload.cpp
+++ b/src/client/preload.cpp
@@ -337,6 +337,9 @@ init_environment() {
 
 } // namespace gkfs::preload
 
+
+std::atomic<bool> init{false};
+
 /**
  * Called initially ONCE when preload library is used with the LD_PRELOAD
  * environment variable
@@ -346,7 +349,10 @@ init_preload() {
     // The original errno value will be restored after initialization to not
     // leak internal error codes
     auto oerrno = errno;
-
+    if(!init) {
+        init = true;
+        pthread_atfork(&at_fork_syscall, &at_parent_syscall, &at_child_syscall);
+    }
     CTX->enable_interception();
     gkfs::preload::start_self_interception();
 
@@ -459,3 +465,24 @@ gkfs_end() {
 
     return 0;
 }
+
+void
+at_fork_syscall() {
+    printf("%d ->At fork, %d\n", gettid(), CTX->interception_enabled());
+    destroy_preload();
+}
+void
+at_parent_syscall() {
+    printf("%d ->At fork parent %d\n", gettid(), CTX->interception_enabled());
+    init_preload();
+    printf("%d -> x At fork parent %d\n", gettid(),
+           CTX->interception_enabled());
+}
+
+void
+at_child_syscall() {
+
+    printf("%d ->At fork child %d\n", gettid(), CTX->interception_enabled());
+    init_preload();
+    printf("%d -> x At fork child %d\n", gettid(), CTX->interception_enabled());
+}
-- 
GitLab


From f8d84e555924c50cd52c09b9be2203780b5169f0 Mon Sep 17 00:00:00 2001
From: Ramon Nou <ramon.nou@bsc.es>
Date: Wed, 27 Nov 2024 14:56:35 +0100
Subject: [PATCH 2/2] Metrics should be nicely cleanup, add destroy_metrics
 function

---
 CHANGELOG.md                       | 1 +
 include/client/preload_context.hpp | 3 +++
 src/client/preload.cpp             | 8 +-------
 src/client/preload_context.cpp     | 8 ++++++++
 4 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c329f6bbc..891b11b8c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
   - Support to print newer syscall (although not implemented). Added syscall number to log for easy capture missing ones.
 - Unify dependency scripts (dl and compile): Unify `-d` and `-p` flags ([!174](https://storage.bsc.es/gitlab/hpc/gekkofs/-/merge_requests/174)).
 - Increased merge assert for files with size 0, specific for DLIO with GekkoFS in Debug ([!208])(https://storage.bsc.es/gitlab/hpc/gekkofs/-/merge_requests/208)).
+- Added code to correct fork issues. `pthread_at_fork` cleans and starts GekkoFS ([!210](https://storage.bsc.es/gitlab/hpc/gekkofs/-/merge_requests/210)).
 ### Removed
 ### Fixed
 
diff --git a/include/client/preload_context.hpp b/include/client/preload_context.hpp
index d818ca21e..7ca56e1a2 100644
--- a/include/client/preload_context.hpp
+++ b/include/client/preload_context.hpp
@@ -153,6 +153,9 @@ public:
     bool
     init_metrics();
 
+    void
+    destroy_metrics();
+
     void
     mountdir(const std::string& path);
 
diff --git a/src/client/preload.cpp b/src/client/preload.cpp
index 6bf27d964..ae7b03817 100644
--- a/src/client/preload.cpp
+++ b/src/client/preload.cpp
@@ -413,6 +413,7 @@ destroy_preload() {
     CTX->read_metrics()->flush_msgpack();
     LOG(INFO, "Metrics flushed. Total flush operations: {}",
         CTX->write_metrics()->flush_count());
+    CTX->destroy_metrics();
 #endif
     CTX->clear_hosts();
     LOG(DEBUG, "Peer information deleted");
@@ -468,21 +469,14 @@ gkfs_end() {
 
 void
 at_fork_syscall() {
-    printf("%d ->At fork, %d\n", gettid(), CTX->interception_enabled());
     destroy_preload();
 }
 void
 at_parent_syscall() {
-    printf("%d ->At fork parent %d\n", gettid(), CTX->interception_enabled());
     init_preload();
-    printf("%d -> x At fork parent %d\n", gettid(),
-           CTX->interception_enabled());
 }
 
 void
 at_child_syscall() {
-
-    printf("%d ->At fork child %d\n", gettid(), CTX->interception_enabled());
     init_preload();
-    printf("%d -> x At fork child %d\n", gettid(), CTX->interception_enabled());
 }
diff --git a/src/client/preload_context.cpp b/src/client/preload_context.cpp
index a15813b25..438bf55a6 100644
--- a/src/client/preload_context.cpp
+++ b/src/client/preload_context.cpp
@@ -121,6 +121,14 @@ PreloadContext::init_logging() {
     );
 }
 
+void
+PreloadContext::destroy_metrics() {
+#ifdef GKFS_ENABLE_CLIENT_METRICS
+    write_metrics_.reset();
+    read_metrics_.reset();
+#endif
+}
+
 bool
 PreloadContext::init_metrics() {
 #ifdef GKFS_ENABLE_CLIENT_METRICS
-- 
GitLab