8fe4536257
We can't use the cache if the file we want to commit has been modified by the client through the file info or xattr modifiers. We would prematurely look into the cache in `write_dfd_iter_to_mtree_internal`, regardless of whether any filtering applied. We remove that path there, and make sure that we only use the cache if there were no modifications. We rename the `get_modified_xattrs` to `get_final_xattrs` to reflect the fact that the xattrs may not be modified. One tricky bit that took me some time was that we now need to store the st_dev & st_ino values in the GFileInfo because the cache lookup relies on it. I'm guessing we regressed on this at some point. This patch does slightly change the semantics of the xattr callback. Previously, returning NULL from the cb meant no xattrs at all. Now, it means to default to the on-disk state. We might want to consider putting that behind a flag instead. Though it seems like a more useful behaviour so that callers can only override the files they want to without losing original on-disk state (and if they don't want that, just return an empty GVariant). Closes: #1165 Closes: #1170 Approved by: cgwalters
libostree
New! See the docs online at Read The Docs (OSTree)
This project is now known as "libostree", though it is still appropriate to use the previous name: "OSTree" (or "ostree"). The focus is on projects which use libostree's shared library, rather than users directly invoking the command line tools (except for build systems). However, in most of the rest of the documentation, we will use the term "OSTree", since it's slightly shorter, and changing all documentation at once is impractical. We expect to transition to the new name over time.
As implied above, libostree is both a shared library and suite of command line tools that combines a "git-like" model for committing and downloading bootable filesystem trees, along with a layer for deploying them and managing the bootloader configuration.
The core OSTree model is like git in that it checksums individual files and has a content-addressed-object store. It's unlike git in that it "checks out" the files via hardlinks, and they should thus be immutable. Therefore, another way to think of OSTree is that it's just a more polished version of Linux VServer hardlinks.
Features:
- Transactional upgrades and rollback for the system
- Replicating content incrementally over HTTP via GPG signatures and "pinned TLS" support
- Support for parallel installing more than just 2 bootable roots
- Binary history on the server side (and client)
- Introspectable shared library API for build and deployment systems
- Flexible support for multiple branches and repositories, supporting projects like flatpak which use libostree for applications, rather than hosts.
Projects using OSTree
meta-updater is a layer available for OpenEmbedded systems.
QtOTA is Qt's over-the-air update framework which uses libostree.
rpm-ostree is a next-generation hybrid package/image system for Fedora and CentOS, used by the Atomic Host project. By default it uses libostree to atomically replicate a base OS (all dependency resolution is done on the server), but it supports "package layering", where additional RPMs can be layered on top of the base. This brings a "best of both worlds"" model for image and package systems.
flatpak uses libostree for desktop application containers. Unlike most of the other systems here, flatpak does not use the "libostree host system" aspects (e.g. bootloader management), just the "git-like hardlink dedup". For example, flatpak supports a per-user OSTree repository.
Endless OS uses libostree for their host system as well as flatpak. See their eos-updater and deb-ostree-builder projects.
GNOME Continuous is where OSTree was born - as a high performance continuous delivery/testing system for GNOME.
Building
Releases are available as GPG signed git tags, and most recent versions support extended validation using git-evtag.
However, in order to build from a git clone, you must update the submodules. If you're packaging OSTree and want a tarball, I recommend using a "recursive git archive" script. There are several available online; this code in OSTree is an example.
Once you have a git clone or recursive archive, building is the same as almost every autotools project:
git submodule update --init
env NOCONFIGURE=1 ./autogen.sh
./configure --prefix=...
make
make install DESTDIR=/path/to/dest
More documentation
New! See the docs online at Read The Docs (OSTree)
Contributing
See Contributing.