Fix: open read-writer after read-only

.github/workflows/publish-conan-branch-package.yml

@@ -10,10 +10,10 @@ jobs:
     uses: dice-group/cpp-conan-release-reusable-workflow/.github/workflows/publish-conan-branch-package.yml@main
     with:
       public_artifactory: true
-      os: ubuntu-22.04
-      compiler: clang-15
+      os: ubuntu-24.04
+      compiler: clang-20
       cmake-version: 3.22.6
-      conan-version: 2.3.0
+      conan-version: 2.17.0
       conan-options: -o boost/*:header_only=True
     secrets:
       CONAN_USER: ${{ secrets.CONAN_USER }}

.github/workflows/publish-release.yml

@@ -16,10 +16,10 @@ jobs:
     uses: dice-group/cpp-conan-release-reusable-workflow/.github/workflows/publish-release.yml@main
     with:
       public_artifactory: true
-      os: ubuntu-22.04
-      compiler: clang-15
+      os: ubuntu-24.04
+      compiler: clang-20
       cmake-version: 3.22.6
-      conan-version: 2.3.0
+      conan-version: 2.17.0
       conan-options: -o boost/*:header_only=True
     secrets:
       CONAN_USER: ${{ secrets.CONAN_USER }}

conanfile.py

@@ -29,7 +29,7 @@ class Recipe(ConanFile):
     generators = "CMakeDeps", "CMakeToolchain"
 
     def requirements(self):
-        self.requires("metall/0.28", transitive_headers=True)
+        self.requires("metall/0.32", transitive_headers=True)
 
         if self.options.with_test_deps:
             self.requires("doctest/2.4.11")

src/dice/ffi/metall.cpp

@@ -7,17 +7,16 @@ using metall_manager_t = dice::metall_ffi::internal::metall_manager;
 
 template<auto open_mode>
 metall_manager *open_impl(char const *path) {
-    if (!metall::manager::consistent(path)) {
-        // prevents opening the same datastore twice
-        // (because opening removes the properly_closed_mark and this checks for it)
-        errno = ENOTRECOVERABLE;
-        return nullptr;
-    }
-
     auto *manager = new metall_manager_t{open_mode, path};
     if (!manager->check_sanity()) {
         delete manager;
-        errno = ENOTRECOVERABLE;
+
+        if (!metall::manager::consistent(path)) {
+            errno = ENOTRECOVERABLE;
+        } else {
+            errno = EBUSY;
+        }
+
         return nullptr;
     }
 

src/dice/ffi/metall.h

@@ -37,7 +37,9 @@ typedef struct metall_manager metall_manager;
  * @brief Attempts to open the metall datastore at path
  * @param path path to datastore
  * @return true on success, false on failure. On failure, sets errno to one of the following values:
- *      - ENOTRECOVERABLE if the given metall datastore is inconsistent
+ *      - ENOTRECOVERABLE if the given metall datastore is inconsistent, or if it is currently open as read-write
+ *          by a previous call to metall_open or metall_create
+ *      - EBUSY if the given metall datastore is already open as read-only
  */
 metall_manager *metall_open(char const *path);
 

tests/tests_Sanity.cpp

@@ -128,4 +128,41 @@ TEST_SUITE("metall-ffi") {
             FAIL("Did not refuse to allocate");
         }
     }
+
+    TEST_CASE("open read-only then read-write") {
+        std::string const path = "/tmp/" + std::to_string(std::random_device{}());
+
+        // create datastore
+        {
+            metall_manager *mgr = metall_create(path.c_str());
+            metall_close(mgr);
+        }
+
+        metall_manager *mgr_ro = metall_open_read_only(path.c_str());
+        CHECK_NE(mgr_ro, nullptr);
+
+        metall_manager *mgr_ro2 = metall_open_read_only(path.c_str());
+        CHECK_NE(mgr_ro2, nullptr);
+
+        metall_manager *mgr_rw = metall_open(path.c_str());
+        CHECK_EQ(mgr_rw, nullptr);
+        CHECK_EQ(errno, EBUSY);
+
+        metall_close(mgr_ro);
+
+        metall_manager *mgr_rw2 = metall_open(path.c_str());
+        CHECK_EQ(mgr_rw2, nullptr);
+        CHECK_EQ(errno, EBUSY);
+
+        metall_close(mgr_ro2);
+
+        metall_manager *mgr_rw3 = metall_open(path.c_str());
+        CHECK_NE(mgr_rw3, nullptr);
+
+        metall_manager *mgr_rw4 = metall_open(path.c_str());
+        CHECK_EQ(mgr_rw4, nullptr);
+        CHECK_EQ(errno, ENOTRECOVERABLE);
+
+        metall_close(mgr_rw3);
+    }
 }