Rather than having separate write_ref calls, make clients start a
transaction, add some refs, and then commit it. While this doesn't
make it 100% atomic, it makes it easier for us to use an atomic
model, and it means we don't do as much I/O updating the summary
file and such.
https://bugzilla.gnome.org/show_bug.cgi?id=707644
An earlier version of this API acted like git in that some objects
would be staged in a temporary directory which would be then committed
in one go by moving files around. The API doesn't match most users
expectations though, as while the stage is nice as a high-level API
it isn't really suited for low-level APIs.
While the stage was removed, the APIs were never renamed. Rename
them now so that they match expectations.
https://bugzilla.gnome.org/show_bug.cgi?id=707644
It turns out every builtin (with one special exception) that takes a
repo argument did the same thing; let's just centralize it. The
special exception was "ostree init --repo=foo" where foo is expected
to *not* actually be a repo. In that case, simply skip the
ostree_repo_check() invocation.
https://bugzilla.gnome.org/show_bug.cgi?id=706762
We removed support for writing "related objects" from ostree commits
in ostree git c9b61cbfee because it just
didn't work out as an idea. This also removes the API and code from
"ostree pull".
Note there was no test suite coverage.
https://bugzilla.gnome.org/show_bug.cgi?id=706342
The way we recurse into subdirectories in parallel makes it far too
easy to hit up against the arbitrary Linux fd limit of 1024.
Since the fix here is about dropping parallelism, let's just go all
the way for now and make a plain old synchronous API =(
This does simplify both internal callers which wanted a sync API
anyways.
https://bugzilla.gnome.org/show_bug.cgi?id=706380
We'll always have "bare" mode for keeping files-as-hardlinks as root.
But "archive" was my second attempt at a format for non-root file
storage, used by the gnome-ostree buildsystem which runs as non-root.
It was really handy to have a "tar" like mode where I can create
tarballs as a user, that contain files owned by root for example.
The "archive" mode stored content files as two pieces in the
filesystem; ".file" contained metadata, and ".filecontent" was the
actual content, uncompressed. The nice thing about this was that to
check out a tree as non-root, you could just hardlink into the repo.
However, archive was fairly bad for serving via HTTP; it required
*two* HTTP requests per content object, greatly magnifing the already
inefficient fetch process. So "archive-z2" was introduced.
To allow gnome-ostree to still check out trees as a user, the
"uncompressed-object-cache" was introduced, and that's how things have
been working for a while.
So we should just be able to kill this code. Specifically note just
how much better the stage_object() function became.
https://bugzilla.gnome.org/show_bug.cgi?id=706057
We have APIs to load metadata as variants, and files as parsed
content/info/xattrs, but for some cases such as static deltas, all we
want is to operate on all objects in their canonical representation.
https://bugzilla.gnome.org/show_bug.cgi?id=706031
While the actual commit object format is presently the same, for a
number of reasons we'd like to change it fairly radically. Among
other things, we need to drop our a{sv} types in objects, to protect
against GVariant changing format.
Since now gnome-ostree now longer uses related objects, and nothing
ever used metadata, just drop them both.
If pull is interrupted, we may have downloaded an arbitrary subset of
the requested objects. Previously, we handled this by scanning for
all objects each time.
However, there's an easy optimization - this patch creates a lock file
in the repo. If we don't see that file when starting a pull, we know
we don't need to stat() every file; presence of a dirtree object for
example implies the existence of everything it references.
This is an incompatible change to archive-z, thus it is now renamed to
archive-z2 and ostree will no longer parse archive-z.
I noticed in perf that we were spending some time zlib-decompressing
file headers, which is just inefficient. Rather than do this, keep
the headers uncompressed, and just zlib-compress content.
This gives us something closer to the advantages of archive and
archive-z when using the latter. Concretely we get deduplication
among multiple checkouts, along with the "devino" hash table trick
during commits to avoid checksumming content again.
This is enabled by default.
For similar reasons as metadata, this avoids having the main thread
blocked in fdatasync(), and even better - we can achieve much higher
parallelism if we have multiple threads blocked on fdatasync().
This is where loose content objects are stored as one compressed file,
instead of the two separate ones for regular archive mode. This mode
would be suitable for HTTP servers, beause only one HTTP request is
necessary, and the result would be compressed.
Cleanly separate metadata/content APIs, rather than defaulting to
raw streams. This helps most use cases.
Also, drop support for staging content without knowing the total
length. This complicated the code, and for things like streaming
HTTP, we should be able to figure this out from Content-Length.
They're not a large efficiency win at the moment, because we don't
do any delta compression.
At the moment, they simply served to compress data, but we will change
the archive mode to do that by default.
This can be a large performance win in certain circumstances:
* Cold buffer cache (we don't block the whole process)
* Requiring a copy instead of hardlink
This will allow us to use hard links again for user-mode checkouts,
rather than the hackish link cache. It was pretty silly anyways to
have file objects be stored with just a small metadata header
prepended, but uncompressed.
Either they should be hardlinkable, or compressed (in pack files).
Colin Walters
Jasper St. Pierre