pull: Implement --enable-syncfs

Differently than fsync that is called after each file is modified,
syncfs is used only once at the end of the pull to sync the file
system which contains the repository.

Results of pull on an empty repository:

$ LANG=C sudo time ./ostree --repo=repo --disable-fsync pull master master
0 metadata, 0 content objects fetched; 83524 KiB; 6 delta parts fetched, transferred in 5 seconds
17.09user 2.41system 0:05.77elapsed 337%CPU (0avgtext+0avgdata 296132maxresident)k
0inputs+868584outputs (0major+102828minor)pagefaults 0swaps

$ LANG=C sudo time ./ostree --repo=repo pull master master
0 metadata, 0 content objects fetched; 83524 KiB; 6 delta parts fetched, transferred in 401 seconds
17.31user 5.73system 6:41.33elapsed 5%CPU (0avgtext+0avgdata 296864maxresident)k
0inputs+868584outputs (0major+132664minor)pagefaults 0swaps

$ LANG=C sudo time ./ostree --repo=repo --enable-syncfs pull master master
0 metadata, 0 content objects fetched; 83524 KiB; 6 delta parts fetched, transferred in 6 seconds
17.14user 2.57system 0:10.60elapsed 185%CPU (0avgtext+0avgdata 296212maxresident)k
0inputs+868584outputs (0major+86783minor)pagefaults 0swaps

Signed-off-by: Giuseppe Scrivano <[email protected]>

src/libostree/ostree-repo-private.h

@@ -60,6 +60,7 @@ struct OstreeRepo {
   gboolean writable;
   gboolean in_transaction;
   gboolean disable_fsync;
+  gboolean enable_syncfs;
   GHashTable *loose_object_devino_hash;
   GHashTable *updated_uncompressed_dirs;
   GHashTable *object_sizes;

src/libostree/ostree-repo-pull.c

@@ -2064,6 +2064,15 @@ ostree_repo_pull_with_options (OstreeRepo             *self,
           }
     }
 
+  if (self->enable_syncfs)
+  {
+    if (syncfs (self->tmp_dir_fd) < 0)
+      {
+        g_set_error_literal (error, G_IO_ERROR, g_io_error_from_errno (errno), g_strerror (errno));
+        goto out;
+      }
+  }
+
   ret = TRUE;
  out:
   g_main_context_unref (pull_data->main_context);

src/libostree/ostree-repo.c

@@ -1418,6 +1418,22 @@ ostree_repo_set_disable_fsync (OstreeRepo    *self,
   self->disable_fsync = disable_fsync;
 }
 
+/**
+ * ostree_repo_set_enable_syncfs:
+ * @self: An #OstreeRepo
+ * @enable_syncfs: If %TRUE, use syncfs instead of fsync
+ *
+ * Use syncfs to synchronize the file system containing the repository
+ * instead of calling fsync on each file.
+ * Should offer better performance as the sync is done only once.
+ */
+void
+ostree_repo_set_enable_syncfs (OstreeRepo    *self,
+                               gboolean       enable_syncfs)
+{
+  self->enable_syncfs = enable_syncfs;
+}
+
 
 /**
  * ostree_repo_get_path:

src/libostree/ostree-repo.h

@@ -52,6 +52,9 @@ gboolean      ostree_repo_open   (OstreeRepo     *self,
 void          ostree_repo_set_disable_fsync (OstreeRepo    *self,
                                              gboolean       disable_fsync);
 
+void          ostree_repo_set_enable_syncfs (OstreeRepo    *self,
+                                             gboolean       enable_syncfs);
+
 gboolean      ostree_repo_is_system (OstreeRepo   *repo);
 
 gboolean      ostree_repo_create (OstreeRepo     *self,

src/ostree/ot-builtin-pull.c

@@ -28,11 +28,13 @@
 #include "otutil.h"
 
 static gboolean opt_disable_fsync;
+static gboolean opt_enable_syncfs;
 static gboolean opt_mirror;
 static char* opt_subpath;
 static int opt_depth = 0;
 
  static GOptionEntry options[] = {
+   { "enable-syncfs", 0, 0, G_OPTION_ARG_NONE, &opt_enable_syncfs, "Use syncfs() instead of fsync()", NULL },
    { "disable-fsync", 0, 0, G_OPTION_ARG_NONE, &opt_disable_fsync, "Do not invoke fsync()", NULL },
    { "mirror", 0, 0, G_OPTION_ARG_NONE, &opt_mirror, "Write refs suitable for a mirror", NULL },
    { "subpath", 0, 0, G_OPTION_ARG_STRING, &opt_subpath, "Only pull the provided subpath", NULL },
@@ -63,6 +65,12 @@ ostree_builtin_pull (int argc, char **argv, GCancellable *cancellable, GError **
       goto out;
     }
 
+  if (opt_enable_syncfs)
+    {
+      ostree_repo_set_disable_fsync (repo, TRUE);
+      ostree_repo_set_enable_syncfs (repo, TRUE);
+    }
+
   if (opt_disable_fsync)
     ostree_repo_set_disable_fsync (repo, TRUE);
 

tests/pull-test.sh

@@ -39,6 +39,7 @@ function verify_initial_contents() {
 repo_init
 ${CMD_PREFIX} ostree --repo=repo pull origin main
 ${CMD_PREFIX} ostree --repo=repo pull origin:main
+${CMD_PREFIX} ostree --repo=repo pull --enable-syncfs origin:main
 ${CMD_PREFIX} ostree --repo=repo fsck
 echo "ok pull"