AU: do not copy filesystem during full updates
The filesystem copying stage is redundant during full updates, where the
partition is being entirely overwritten regardless of its previous
content. It is also a very wasteful step, causing intensive I/O and
kernel buffer pressure, and known to (sometimes) cause jank and
otherwise have detrimental effects on our user experience.
This CL eliminates filesystem copying for full updates:
1) The decision is based on whether the Omaha response indicates that
this is a full update.
2) To be safe, we also ensure that the payload manifest does not contain
old partition hashes, which is indicative of a delta update.
Note that it is generally desirable to base the decision solely on #2
above (and ignore #1 altogether). However, this will require more
extensive re-engineering of the update flow, as filesystem copying
currently happens prior to the manifest being downloaded.
BUG=chromium:189855
TEST=Full and delta updates run correctly on x86-alex
Change-Id: Ic0dc6e32913cfb96019606624ec6b87c2e5b3ebb
Reviewed-on: https://gerrit.chromium.org/gerrit/43665
Commit-Queue: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Gilad Arnold <garnold@chromium.org>
Tested-by: Gilad Arnold <garnold@chromium.org>
diff --git a/filesystem_copier_action.cc b/filesystem_copier_action.cc
index 7024b67..3e5160e 100644
--- a/filesystem_copier_action.cc
+++ b/filesystem_copier_action.cc
@@ -69,8 +69,11 @@
return;
}
install_plan_ = GetInputObject();
- if (!verify_hash_ && install_plan_.is_resume) {
+ if (!verify_hash_ &&
+ (install_plan_.is_resume || install_plan_.is_full_update)) {
// No copy or hash verification needed. Done!
+ LOG(INFO) << "filesystem copying skipped: "
+ << (install_plan_.is_resume ? "resumed" : "full") << " update";
if (HasOutputPipe())
SetOutputObject(install_plan_);
abort_action_completer.set_code(kErrorCodeSuccess);