Issue 678856 link

Starred by 2 users

Issue metadata

Status:	WontFix
Owner:	dgarr...@chromium.org
Closed:	Jul 2017
Cc:	aaboagye@chromium.org █ de...@chromium.org █ chingcodes@chromium.org
Components:	Infra>Client>ChromeOS
EstimatedDays:	----
NextAction:	----
OS:	Chrome
Pri:	3
Type:	Feature

Paygen copies Images more than needed.

Project Member Reported by dgarr...@chromium.org, Jan 6 2017

Issue description

Paygen download both source and target images using the download cache implemented in chromite/lib/paygen/download_cache.py.

It then copies these image into temporary files before generating payloads. It can use a great deal of temporary space, since we generate payloads in parallel, and can end up with multiple temporary copies of the same image.

This used to be necessary when we loopback mounted images, but probably isn't any more.

Comment 1 by dgarr...@chromium.org, Jan 6 2017

Cc: chingcodes@chromium.org
Owner: dgarr...@chromium.org

Currently the download cache does not support direct access to files inside the cache. To fix this 100% safely, we'll need to add a purge locking mechanism to protect files while they are in use (not overly difficult, the cache already has multiprocess locking support).

Also, to verify that this change is really safe, it might be best to temporarily add sanity code that verifies md5 hashes of the images before/after payload generation.

Comment 2 by de...@chromium.org, Jan 6 2017

SGTM.

There's some code in the script (cros_generate_update_payload) that extracts some files from the stateful partition. Please double check that we use e2cp and we don't mount them.