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/install_plan.cc b/install_plan.cc
index 59bd5da..a17cb52 100644
--- a/install_plan.cc
+++ b/install_plan.cc
@@ -13,6 +13,7 @@
namespace chromeos_update_engine {
InstallPlan::InstallPlan(bool is_resume,
+ bool is_full_update,
const string& url,
uint64_t payload_size,
const string& payload_hash,
@@ -21,6 +22,7 @@
const string& install_path,
const string& kernel_install_path)
: is_resume(is_resume),
+ is_full_update(is_full_update),
download_url(url),
payload_size(payload_size),
payload_hash(payload_hash),
@@ -34,6 +36,7 @@
powerwash_required(false) {}
InstallPlan::InstallPlan() : is_resume(false),
+ is_full_update(false), // play it safe.
payload_size(0),
metadata_size(0),
kernel_size(0),
@@ -44,6 +47,7 @@
bool InstallPlan::operator==(const InstallPlan& that) const {
return ((is_resume == that.is_resume) &&
+ (is_full_update == that.is_full_update) &&
(download_url == that.download_url) &&
(payload_size == that.payload_size) &&
(payload_hash == that.payload_hash) &&
@@ -59,7 +63,8 @@
void InstallPlan::Dump() const {
LOG(INFO) << "InstallPlan: "
- << (is_resume ? ", resume" : ", new_update")
+ << (is_resume ? "resume" : "new_update")
+ << ", payload type: " << (is_full_update ? "full" : "delta")
<< ", url: " << download_url
<< ", payload size: " << payload_size
<< ", payload hash: " << payload_hash