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author | Colin Walters <walters@verbum.org> | 2021-12-03 14:35:12 -0500 |
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committer | Colin Walters <walters@verbum.org> | 2021-12-03 14:42:03 -0500 |
commit | 2c39bd88a9b0db207c1158c76bbbe0b484dec9dd (patch) | |
tree | b6464ca6f1215542f8e7b4311d69d62096e75482 /src/libostree/ostree-repo-checkout.c | |
parent | 267ca93da28e00adb3f961d208821bba4644a2d4 (diff) | |
download | ostree-2c39bd88a9b0db207c1158c76bbbe0b484dec9dd.tar.gz |
repo: Change locking for summary regeneration to be shared
This is trying to address:
https://pagure.io/fedora-iot/issue/48
Basically we changed rpm-ostree to start doing a shared lock during
commit by default, but this broke because pungi is starting a process
doing a commit for each architecture, and then trying to regenerate
the summary after each one.
This patch is deleting a big comment with a rationale for why
summary regeneration should be exclusive. Point by point:
> This makes sure the commits and deltas don't get
> deleted while generating the summary.
But prune operations require an exclusive lock, which means that
data still can't be deleted when the summary grabs a shared lock.
> It also means we can be sure refs
> won't be created/updated/deleted during the operation, without having to
> add exclusive locks to those operations which would prevent concurrent
> commits from working.
First: The status quo *has* prevented concurrent commits from working!
There is no real locking solution to this problem. What we really
need to do here is regenerate the summary after each commit *or*
when the caller decides to do it and e.g. include deltas at the same
time.
It's OK if multiple threads race to regenerate the summary;
last-one-wins behavior here is totally fine.
Diffstat (limited to 'src/libostree/ostree-repo-checkout.c')
0 files changed, 0 insertions, 0 deletions