Repo locking API backport

Makefile.am

@@ -31,7 +31,7 @@ AM_CPPFLAGS += -DDATADIR='"$(datadir)"' -DLIBEXECDIR='"$(libexecdir)"' \
 	-DOSTREE_COMPILATION \
 	-DG_LOG_DOMAIN=\"OSTree\" \
   -DOSTREE_GITREV='"$(OSTREE_GITREV)"' \
-	-DGLIB_VERSION_MIN_REQUIRED=GLIB_VERSION_2_40 '-DGLIB_VERSION_MAX_ALLOWED=G_ENCODE_VERSION(2,50)' \
+	-DGLIB_VERSION_MIN_REQUIRED=GLIB_VERSION_2_44 '-DGLIB_VERSION_MAX_ALLOWED=G_ENCODE_VERSION(2,50)' \
 	-DSOUP_VERSION_MIN_REQUIRED=SOUP_VERSION_2_40 '-DSOUP_VERSION_MAX_ALLOWED=G_ENCODE_VERSION(2,48)'
 # For strict aliasing, see https://bugzilla.gnome.org/show_bug.cgi?id=791622
 AM_CFLAGS += -std=gnu99 -fno-strict-aliasing $(WARN_CFLAGS)

apidoc/ostree-sections.txt

@@ -310,6 +310,12 @@ ostree_repo_get_min_free_space_bytes
 ostree_repo_get_config
 ostree_repo_get_dfd
 ostree_repo_get_default_repo_finders
+OstreeRepoLockType
+ostree_repo_lock_pop
+ostree_repo_lock_push
+OstreeRepoAutoLock
+ostree_repo_auto_lock_push
+ostree_repo_auto_lock_cleanup
 ostree_repo_hash
 ostree_repo_equal
 ostree_repo_copy_config

configure.ac

@@ -114,7 +114,7 @@ AM_PATH_GLIB_2_0(,,AC_MSG_ERROR([GLib not found]))
 dnl When bumping the gio-unix-2.0 dependency (or glib-2.0 in general),
 dnl remember to bump GLIB_VERSION_MIN_REQUIRED and
 dnl GLIB_VERSION_MAX_ALLOWED in Makefile.am
-GIO_DEPENDENCY="gio-unix-2.0 >= 2.40.0"
+GIO_DEPENDENCY="gio-unix-2.0 >= 2.44.0"
 PKG_CHECK_MODULES(OT_DEP_GIO_UNIX, $GIO_DEPENDENCY)
 
 dnl 5.1.0 is an arbitrary version here

src/libostree/libostree-released.sym

@@ -638,6 +638,18 @@ global:
   ostree_repo_gpg_sign_data;
 } LIBOSTREE_2020.7;
 
+/* Endless backported symbols. Note that the upstream symbol version is
+ * used so that programs linking to the symbols don't need to be rebuilt
+ * when we get to the upstream release containing the symbols.
+ */
+LIBOSTREE_2021.3 {
+global:
+  ostree_repo_auto_lock_push;
+  ostree_repo_auto_lock_cleanup;
+  ostree_repo_lock_push;
+  ostree_repo_lock_pop;
+} LIBOSTREE_2020.8;
+
 /* NOTE: Only add more content here in release commits!  See the
  * comments at the top of this file.
  */

src/libostree/ostree-repo-commit.c

@@ -1794,8 +1794,8 @@ ostree_repo_prepare_transaction (OstreeRepo     *self,
 
   memset (&self->txn.stats, 0, sizeof (OstreeRepoTransactionStats));
 
-  self->txn_locked = _ostree_repo_lock_push (self, OSTREE_REPO_LOCK_SHARED,
-                                             cancellable, error);
+  self->txn_locked = ostree_repo_lock_push (self, OSTREE_REPO_LOCK_SHARED,
+                                            cancellable, error);
   if (!self->txn_locked)
     return FALSE;
 
@@ -2451,7 +2451,7 @@ ostree_repo_commit_transaction (OstreeRepo                  *self,
 
   if (self->txn_locked)
     {
-      if (!_ostree_repo_lock_pop (self, cancellable, error))
+      if (!ostree_repo_lock_pop (self, OSTREE_REPO_LOCK_SHARED, cancellable, error))
         return FALSE;
       self->txn_locked = FALSE;
     }
@@ -2509,7 +2509,7 @@ ostree_repo_abort_transaction (OstreeRepo     *self,
 
   if (self->txn_locked)
     {
-      if (!_ostree_repo_lock_pop (self, cancellable, error))
+      if (!ostree_repo_lock_pop (self, OSTREE_REPO_LOCK_SHARED, cancellable, error))
         return FALSE;
       self->txn_locked = FALSE;
     }

src/libostree/ostree-repo-private.h

@@ -104,6 +104,13 @@ typedef struct {
   fsblkcnt_t max_blocks;
 } OstreeRepoTxn;
 
+typedef struct {
+  GMutex mutex;  /* All other members should only be accessed with this held */
+  int fd;  /* The open file or flock file descriptor */
+  guint shared;  /* Number of shared locks curently held */
+  guint exclusive;  /* Number of exclusive locks currently held */
+} OstreeRepoLock;
+
 typedef enum {
   _OSTREE_FEATURE_NO,
   _OSTREE_FEATURE_MAYBE,
@@ -159,6 +166,8 @@ struct OstreeRepo {
   GWeakRef sysroot; /* Weak to avoid a circular ref; see also `is_system` */
   char *remotes_config_dir;
 
+  OstreeRepoLock lock;
+
   GMutex txn_lock;
   OstreeRepoTxn txn;
   gboolean txn_locked;
@@ -496,30 +505,6 @@ _ostree_repo_maybe_regenerate_summary (OstreeRepo    *self,
                                        GCancellable  *cancellable,
                                        GError       **error);
 
-/* Locking APIs are currently private.
- * See https://github.com/ostreedev/ostree/pull/1555
- */
-typedef enum {
-  OSTREE_REPO_LOCK_SHARED,
-  OSTREE_REPO_LOCK_EXCLUSIVE
-} OstreeRepoLockType;
-
-gboolean      _ostree_repo_lock_push (OstreeRepo          *self,
-                                     OstreeRepoLockType   lock_type,
-                                     GCancellable        *cancellable,
-                                     GError             **error);
-gboolean      _ostree_repo_lock_pop (OstreeRepo    *self,
-                                     GCancellable  *cancellable,
-                                     GError       **error);
-
-typedef OstreeRepo OstreeRepoAutoLock;
-
-OstreeRepoAutoLock * _ostree_repo_auto_lock_push (OstreeRepo          *self,
-                                                  OstreeRepoLockType   lock_type,
-                                                  GCancellable        *cancellable,
-                                                  GError             **error);
-void          _ostree_repo_auto_lock_cleanup (OstreeRepoAutoLock *lock);
-G_DEFINE_AUTOPTR_CLEANUP_FUNC (OstreeRepoAutoLock, _ostree_repo_auto_lock_cleanup)
 
 gboolean
 _ostree_tmpf_fsverity_core (GLnxTmpfile *tmpf,

src/libostree/ostree-repo-prune.c

@@ -204,7 +204,7 @@ ostree_repo_prune_static_deltas (OstreeRepo *self, const char *commit,
                                  GError           **error)
 {
   g_autoptr(OstreeRepoAutoLock) lock =
-    _ostree_repo_auto_lock_push (self, OSTREE_REPO_LOCK_EXCLUSIVE, cancellable, error);
+    ostree_repo_auto_lock_push (self, OSTREE_REPO_LOCK_EXCLUSIVE, cancellable, error);
   if (!lock)
     return FALSE;
 
@@ -325,7 +325,7 @@ ostree_repo_traverse_reachable_refs (OstreeRepo *self,
                                      GError      **error)
 {
   g_autoptr(OstreeRepoAutoLock) lock =
-    _ostree_repo_auto_lock_push (self, OSTREE_REPO_LOCK_SHARED, cancellable, error);
+    ostree_repo_auto_lock_push (self, OSTREE_REPO_LOCK_SHARED, cancellable, error);
   if (!lock)
     return FALSE;
 
@@ -400,7 +400,7 @@ ostree_repo_prune (OstreeRepo        *self,
                    GError           **error)
 {
   g_autoptr(OstreeRepoAutoLock) lock =
-    _ostree_repo_auto_lock_push (self, OSTREE_REPO_LOCK_EXCLUSIVE, cancellable, error);
+    ostree_repo_auto_lock_push (self, OSTREE_REPO_LOCK_EXCLUSIVE, cancellable, error);
   if (!lock)
     return FALSE;
 
@@ -486,7 +486,7 @@ ostree_repo_prune_from_reachable (OstreeRepo        *self,
                                   GError           **error)
 {
   g_autoptr(OstreeRepoAutoLock) lock =
-    _ostree_repo_auto_lock_push (self, OSTREE_REPO_LOCK_EXCLUSIVE, cancellable, error);
+    ostree_repo_auto_lock_push (self, OSTREE_REPO_LOCK_EXCLUSIVE, cancellable, error);
   if (!lock)
     return FALSE;
 

src/libostree/ostree-repo-static-delta-core.c

@@ -1268,7 +1268,7 @@ ostree_repo_static_delta_reindex (OstreeRepo                 *repo,
 
   /* Protect against parallel prune operation */
   g_autoptr(OstreeRepoAutoLock) lock =
-    _ostree_repo_auto_lock_push (repo, OSTREE_REPO_LOCK_SHARED, cancellable, error);
+    ostree_repo_auto_lock_push (repo, OSTREE_REPO_LOCK_SHARED, cancellable, error);
   if (!lock)
     return FALSE;