[ostree] Add a checkout option to skip fsync

[Colin Walters <walters src gnome org>]

commit cd0a9d3435d052f4f994673f1682e4c15b897458
Author: Colin Walters <walters verbum org>
Date:   Sat Jan 23 15:07:55 2016 -0500

    Add a checkout option to skip fsync
    
    This is a better followup to dc9239dd7b09ef5e104309b4dbf0e136889da274
    since I wanted to do fsync-less checkouts in rpm-ostree too, and
    replicating the "turn off fsync temporarily" was in retrospect just a
    hack.
    
    We can simply add a boolean to the checkout options.
    
    https://github.com/GNOME/ostree/pull/172

 src/libostree/ostree-repo-checkout.c  |   34 ++++++++++++++++++--------------
 src/libostree/ostree-repo.h           |    3 +-
 src/libostree/ostree-sysroot-deploy.c |   23 ++++++++-------------
 3 files changed, 30 insertions(+), 30 deletions(-)
---
diff --git a/src/libostree/ostree-repo-checkout.c b/src/libostree/ostree-repo-checkout.c
index ad309e7..0d0e7ef 100644
--- a/src/libostree/ostree-repo-checkout.c
+++ b/src/libostree/ostree-repo-checkout.c
@@ -103,8 +103,15 @@ checkout_object_for_uncompressed_cache (OstreeRepo      *self,
 }
 
 static gboolean
+fsync_is_enabled (OstreeRepo   *self,
+                  OstreeRepoCheckoutOptions *options)
+{
+  return !(self->disable_fsync || options->disable_fsync);
+}
+
+static gboolean
 write_regular_file_content (OstreeRepo            *self,
-                            OstreeRepoCheckoutMode mode,
+                            OstreeRepoCheckoutOptions *options,
                             GOutputStream         *output,
                             GFileInfo             *file_info,
                             GVariant              *xattrs,
@@ -113,6 +120,7 @@ write_regular_file_content (OstreeRepo            *self,
                             GError               **error)
 {
   gboolean ret = FALSE;
+  const OstreeRepoCheckoutMode mode = options->mode;
   int fd;
   int res;
 
@@ -154,12 +162,12 @@ write_regular_file_content (OstreeRepo            *self,
         }
     }
           
-  if (!self->disable_fsync)
+  if (fsync_is_enabled (self, options))
     {
       if (fsync (fd) == -1)
         {
           gs_set_error_from_errno (error, errno);
-      goto out;
+          goto out;
         }
     }
           
@@ -238,7 +246,7 @@ checkout_file_from_input_at (OstreeRepo     *self,
       temp_out = g_unix_output_stream_new (fd, TRUE);
       fd = -1; /* Transfer ownership */
 
-      if (!write_regular_file_content (self, options->mode, temp_out, file_info, xattrs, input,
+      if (!write_regular_file_content (self, options, temp_out, file_info, xattrs, input,
                                        cancellable, error))
         goto out;
     }
@@ -298,7 +306,7 @@ checkout_file_unioning_from_input_at (OstreeRepo     *repo,
                                       cancellable, error))
         goto out;
 
-      if (!write_regular_file_content (repo, options->mode, temp_out, file_info, xattrs, input,
+      if (!write_regular_file_content (repo, options, temp_out, file_info, xattrs, input,
                                        cancellable, error))
         goto out;
     }
@@ -726,17 +734,13 @@ checkout_tree_at (OstreeRepo                        *self,
         }
     }
 
-  /* Finally, fsync to ensure all entries are on disk.  Ultimately
-   * this should be configurable for the case where we're constructing
-   * buildroots.
-   */
-  if (!self->disable_fsync)
+  if (fsync_is_enabled (self, options))
     {
-    if (fsync (destination_dfd) == -1)
-      {
-        gs_set_error_from_errno (error, errno);
-        goto out;
-      }
+      if (fsync (destination_dfd) == -1)
+        {
+          gs_set_error_from_errno (error, errno);
+          goto out;
+        }
     }
 
   ret = TRUE;
diff --git a/src/libostree/ostree-repo.h b/src/libostree/ostree-repo.h
index fd2b7f0..d4d0f41 100644
--- a/src/libostree/ostree-repo.h
+++ b/src/libostree/ostree-repo.h
@@ -532,7 +532,8 @@ typedef struct {
   OstreeRepoCheckoutOverwriteMode overwrite_mode;
   
   guint enable_uncompressed_cache : 1;
-  guint unused : 31;
+  guint disable_fsync : 1;
+  guint reserved : 30;
 
   const char *subpath;
 
diff --git a/src/libostree/ostree-sysroot-deploy.c b/src/libostree/ostree-sysroot-deploy.c
index 1524a86..3dcf39f 100644
--- a/src/libostree/ostree-sysroot-deploy.c
+++ b/src/libostree/ostree-sysroot-deploy.c
@@ -528,6 +528,11 @@ checkout_deployment_tree (OstreeSysroot     *sysroot,
   glnx_fd_close int osdeploy_dfd = -1;
   int ret_fd;
 
+  /* We end up using syncfs for the entire filesystem, so turn off
+   * OstreeRepo level fsync.
+   */
+  checkout_opts.disable_fsync = TRUE;
+
   osdeploy_path = g_strconcat ("ostree/deploy/", ostree_deployment_get_osname (deployment), "/deploy", NULL);
   checkout_target_name = g_strdup_printf ("%s.%d", csum, ostree_deployment_get_deployserial (deployment));
 
@@ -540,20 +545,10 @@ checkout_deployment_tree (OstreeSysroot     *sysroot,
   if (!glnx_shutil_rm_rf_at (osdeploy_dfd, checkout_target_name, cancellable, error))
     goto out;
 
- /* We end up using syncfs for the entire filesystem, so turn off
-   * OstreeRepo level fsync.
-   */
-  { gboolean fsync_was_disabled = ostree_repo_get_disable_fsync (repo);
-    gboolean checkout_success;
-
-    ostree_repo_set_disable_fsync (repo, TRUE);
-    checkout_success = ostree_repo_checkout_tree_at (repo, &checkout_opts, osdeploy_dfd,
-                                                     checkout_target_name, csum,
-                                                     cancellable, error);
-    ostree_repo_set_disable_fsync (repo, fsync_was_disabled);
-    if (!checkout_success)
-      goto out;
-  }
+  if (!ostree_repo_checkout_tree_at (repo, &checkout_opts, osdeploy_dfd,
+                                     checkout_target_name, csum,
+                                     cancellable, error))
+    goto out;
 
   if (!glnx_opendirat (osdeploy_dfd, checkout_target_name, TRUE, &ret_fd, error))
     goto out;