Commit Graph

1999 Commits

Author SHA1 Message Date
Simon McVittie 854d02fbe3 New upstream version 2018.9.1 2018-10-30 10:59:22 +00:00
Umang Jain f3eba6bcec Release 2018.9
Closes: #1761
Approved by: cgwalters
2018-10-24 18:46:39 +00:00
Matthew Leeds ed41822b45 Rename core.repo-finders to core.default-repo-finders
This renames a config key to make its semantics more obvious. Despite
what the commit message says, it only applies when a set of repo finders
is not specified (either on the command line or in a library API call).
This also renames the corresponding ostree_repo_get function. We can do
this since it hasn't been released yet.

Closes: #1763
Approved by: pwithnall
2018-10-23 14:26:50 +00:00
Matthew Leeds 3fc46f37f7 lib/repo-pull: Add an explanatory comment
Closes: #1763
Approved by: pwithnall
2018-10-23 14:26:50 +00:00
Jonathan Lebon ac1a919ffd boot: Add ostree-finalize-staged.path
Rather than manually starting the `ostree-finalize-staged.service` unit,
we can leverage systemd's path units for this. It fits quite nicely too,
given that we already have a path we drop iif we have a staged
deployment.

To give some time for the preset to make it to systems, we don't yet
drop the explicit call to `systemctl start`. Though we do make it
conditional based on a DEBUG env var so that we can actually test it in
CI for now. Once we're sure this has propagated, we can drop the
`systemctl start` path and the env var together.

Closes: #1740
Approved by: cgwalters
2018-10-23 13:10:49 +00:00
Matthew Leeds 1d6347fe97 lib/repo-pull: Disable LAN updates by default
This commit disables searching on the local network for refs, unless
explicitly requested by the user either by changing the value of the
"core.repo-finders" config option, or by passing an OstreeRepoFinderAvahi to
ostree_repo_find_remotes_async() / ostree_repo_finder_resolve_async(),
or by specifying "lan" in the --finders option of the find-remotes
command.

The primary reason for this is that ostree_repo_find_remotes_async()
takes about 40% longer to complete with the LAN finder enabled, and that
API is used widely (e.g. in every flatpak operation). It's also probable
that some users don't want ostree doing potentially unexpected traffic
on the local network, even though everything pulled from a peer is GPG
verified.

Flathub will soon deploy collection IDs to everyone[1] so these code
paths will soon see a lot more use and that's why this change is being
made now.

Endless is the only potential user of the LAN updates feature, and we
can revert this patch on our fork of ostree. For it to be used outside
Endless OS we will need to upstream eos-updater-avahi and
eos-update-server into ostree.

[1] https://github.com/flathub/flathub/issues/676

Closes: #1758
Approved by: cgwalters
2018-10-21 19:11:43 +00:00
Matthew Leeds 3956fc885b Allow disabling pulling from LAN/USB/Internet
Currently libostree essentially has two modes when it's pulling refs:
the "legacy" code paths pull only from the Internet, and the code paths
that are aware of collection IDs try to pull from the Internet, the
local network, and mounted filesystems (such as USB drives). The problem
is that while we eventually want to migrate everyone to using collection
IDs, we don't want to force checking LAN and USB sources if the user
just wants to pull from the Internet, since the LAN/USB code paths can
have privacy[1], security[2], and performance[3] implications.

So this commit implements a new repo config option called "repo-finders"
which can be configured to, for example, "config;lan;mount;" to check
all three sources or "config;mount;" to disable searching the LAN. The
set of values mirror those used for the --finders option of the
find-remotes command. This configuration affects pulls in three places:
1. the ostree_repo_find_remotes_async() API, regardless of whether or
not the user of the API provided a list of OstreeRepoFinders
2. the ostree_repo_finder_resolve_async() /
ostree_repo_finder_resolve_all_async() API
3. the find-remotes command

This feature is especially important right now since we soon want to
have Flathub publish a metadata key which will have Flatpak clients
update the remote config to add a collection ID.[4]

This effectively fixes https://github.com/flatpak/flatpak/issues/1863
but I'll patch Flatpak too, so it doesn't pass finders to libostree only
to then have them be removed.

[1] https://github.com/flatpak/flatpak/issues/1863#issuecomment-404128824
[2] https://github.com/ostreedev/ostree/issues/1527
[3] Based on how long the "ostree find-remotes" command takes to
  complete, having the LAN finder enabled slows down that step of the
  pull process by about 40%. See also
  https://github.com/flatpak/flatpak/issues/1862
[4] https://github.com/flathub/flathub/issues/676

Closes: #1758
Approved by: cgwalters
2018-10-21 19:11:43 +00:00
Colin Walters 1db0db3d7a sysroot: Add error prefixing to deployment parsing
I think this is where the bare `readlinkat` came from in
https://github.com/ostreedev/ostree/issues/1459

`Error setting up sysroot: readlinkat: No such file or directory`

Closes: #1757
Approved by: jlebon
2018-10-17 16:17:18 +00:00
Colin Walters 5183c8f35e sysroot: Update some code to use fstatat_allow_noent API
It's much easier to read and use correctly.  Making this change
since I saw an unprefixed error in an issue.

Closes: #1757
Approved by: jlebon
2018-10-17 16:17:18 +00:00
Dan Nicholson 43d9cac4fc lib/commit: Don't chown objects to repo target owner
The idea is that if the process is running as root, it can change
ownership of newly written files to match the owner of the repo.
Unfortunately, it currently applies in the other direction, too - a
non-root user writing to a root owned repository. If the repo is
writable by the user but owned by root, it can still create files and
directories there, but it can't change ownership of them.

This feature comes from
https://bugzilla.gnome.org/show_bug.cgi?id=738954. As it turns out, this
feature was never completed. It only works on content objects and not
metadata objects, refs, deltas, summaries, etc. Rather than try to fix
all of those, remove the feature until someone has interest in
completing it.

Closes: #1754
Approved by: cgwalters
2018-10-12 12:34:57 +00:00
Colin Walters 9367a1befe checkout: Support --union-identical and --force-copy{,--zerosized}
Actually testing the patch to add `--force-copy-zerosized` to
rpm-ostree tripped over the fact that it uses `--union-identical`,
and we just hit an assertion failure with that combination.

Fix this by copying over the logic we have for the hardlink case.

Closes: #1753
Approved by: jlebon
2018-10-11 20:49:54 +00:00
Colin Walters 673cacd633 repo: Add a checkout option to not hardlink zero-sized files
In rpm-ostree we've hit a few cases where hardlinking zero-sized
files causes us problems.  The most prominent is lock files in
`/usr/etc`, such as `/usr/etc/selinux/semanage.LOCK`.  If there
are two zero-sized lock files to grab, but they're hardlinked,
then locking will fail.

Another case here is if one is using ostree inside a container
and don't have access to FUSE (i.e. `rofiles-fuse`), then the
ostree hardlinking can cause files that aren't ordinarily hardlinked
to become so, and mutation of one mutates all.  An example where
this is concerning is Python `__init__.py` files.

Now, these lock files should clearly not be in the tree to begin
with, but - we're not gaining a huge amount by hardlinking these
files either, so let's add an option to disable it.

Closes: #1752
Approved by: jlebon
2018-10-11 16:32:25 +00:00
Jonathan Lebon 05e99da7a7 lib/sysroot-deploy: Write to journal when finalizing
Write to the journal when starting to finalize a staged deployment.
Combined with the "Transaction completed" message we already emit, this
makes it easy later on to determine whether the operation was successful
by inspecting the journal. This will be used by `rpm-ostree status`.

Closes: #1750
Approved by: cgwalters
2018-10-05 21:17:54 +00:00
Colin Walters 2c55bc6997 Only verify OSTREE_MAX_METADATA_SIZE for HTTP fetches
There are use cases for libostree as a local content store
for content derived or delivered via other mechanisms (e.g. OCI
images, RPMs, etc.).  rpm-ostree today imports RPMs into OSTree
branches, and puts the RPM header value as commit metadata.
Some of these can be quite large because the header includes
permissions for each file.  Similarly, some OCI metadata is large.

Since there's no security issues with this, support committing
such content.

We still by default limit the size of metadata fetches, although
for good measure we make this configurable too via a new
`max-metadata-size` value.

Closes: https://github.com/ostreedev/ostree/issues/1721

Closes: #1744
Approved by: jlebon
2018-10-01 13:23:50 +00:00
Jonathan Lebon 39d5db7e1e lib/mutable-tree: Port to new style
Some therapeutic style conversion to finish off the week. Pretty
straightforward overall.

Closes: #1742
Approved by: cgwalters
2018-09-28 21:49:36 +00:00
Colin Walters 899b0bfad2 lib/progress: Fix leak of GSource
Closes: https://github.com/ostreedev/ostree/issues/1738

Closes: #1741
Approved by: jlebon
2018-09-28 21:40:41 +00:00
Matthew Leeds 7892d35c0b lib/repo: Fix minor mistake in locking docs
The config option is "lock-timeout-secs" not "lock-timeout".

Closes: #1737
Approved by: jlebon
2018-09-28 15:49:11 +00:00
Matthew Leeds 0c8a6d64ed lib/repo: Allow disabling lock timeout
Currently the locking code checks if the value -1 was set for the config
key "lock-timeout-secs" and if so, a thread trying to acquire a lock
will block indefinitely. Positive values specify how long to attempt to
acquire a lock in a non-blocking way (the attempt is made once every
second). But when the value is read from the config file,
g_ascii_strtoull() is used, which converts it to an unsigned integer.
This commit makes libostree use g_ascii_strtoll() instead, so that it's
possible to set that key to -1 as intended.

Closes: #1737
Approved by: jlebon
2018-09-28 15:49:11 +00:00
Colin Walters c141fe610b lib/commit: Don't copy xattrs for metadata objects
Copying the xattrs on metadata objects is wrong in general, we
don't "own" them.  Notably this would fail in the situation of
doing a pull from e.g. a `bare-user` source to a destination
that was on a different mount point (so we couldn't hardlink),
and the source had e.g. a `security.selinux` attribute.

Closes: #1734

Closes: #1736
Approved by: jlebon
2018-09-25 14:49:22 +00:00
Jonathan Lebon 4aadbe2159 lib/fetcher-curl: Prefix fatal errors with full URL
Just include the whole URL that failed if libcurl failed with something
elementary like CURLE_COULDNT_CONNECT or CURLE_COULDNT_RESOLVE_HOST.

Closes: #1731

Closes: #1732
Approved by: cgwalters
2018-09-21 18:43:09 +00:00
Jonathan Lebon a88032a09e lib/fetcher-curl: Drop unnecessary check
`_ostree_fetcher_journal_failure()` already checks that we only log
messages which have remotes.

Closes: #1732
Approved by: cgwalters
2018-09-21 18:43:09 +00:00
Jonathan Lebon 8b2940aa13 lib/fetcher-util: Mark journaled msgs as LOG_ERR
E.g. for filtering, and so it shows up in red.

Closes: #1732
Approved by: cgwalters
2018-09-21 18:43:09 +00:00
Colin Walters 44d5f1cb8c deploy: Fix removing /var/.updated with separate /var mount
There's some subtlety to this, we don't handle all cases.
But the 99% cases are using `--sysroot deploy` to create an
initial deployment, and then doing upgrades from inside
a booted deployment.

It was only the latter case that didn't work with a separate `/var`.
Fixing all of them would probably require libostree to learn
how to e.g. look at `/etc/fstab` (or worse, systemd mount units?)
and handle the mounting.  I don't think we want to do anything
like that right now, since there are no active drivers for the
use case.

Closes: https://github.com/ostreedev/ostree/issues/1729

Closes: #1730
Approved by: akiernan
2018-09-21 15:47:43 +00:00
Umang Jain a0937b6cf0 lib/repo: Separate min-free-space-* calculation from transaction codepath
Earlier, the actual reserved space (in blocks) were calculated inside the
transaction codepath ostree_repo_prepare_transaction(). However, while
reworking on ostree_repo_get_min_free_space_bytes() API, it was realized that
this calculation can be done independently from the transaction's codepaths, hence
enabling the usage for ostree_repo_get_min_free_space_bytes() API irrespective
of whether there is an ongoing transaction or not.

https://github.com/ostreedev/ostree/issues/1720

Closes: #1722
Approved by: pwithnall
2018-09-21 15:09:12 +00:00
Matthew Leeds fc84fb402c lib/repo: Define a metadata key, ostree.deploy-collection-id
This commit defines a metadata key that tells clients to update their
remote config to add a collection ID. This functionality is currently
implemented in Flatpak for the key "xa.collection-id", but there are two
good reasons for moving the key to OSTree:

1) Servers such as Flathub shouldn't set xa.collection-id in their
metadata now or in the medium term future, because many users are still
using old versions of Flatpak and OSTree[1] which would hit various
bugs[2][3][4] on the P2P code paths that are enabled by collection IDs.
Defining a new key means that only clients running recent
(as-yet-unreleased) versions of Flatpak and OSTree will pay attention to
it and deploy the collection ID, leaving the users on old versions
unaffected.

2) OSTree is as "invested" in collection IDs as Flatpak, so there's no
reason the key should be defined in Flatpak rather than here. According
to Philip Withnall, the reason the key was put in Flatpak originally was
that at the time there was uncertainty about tying OSTree to collection
IDs.

[1] https://ahayzen.com/direct/flathub.html#downloadsbyflatpakstacked
[2] https://github.com/ostreedev/ostree/commit/e4e6d85ea
[3] https://github.com/flatpak/flatpak/commit/5813639f
[4] https://github.com/flatpak/flatpak/commit/5b21a5b7

Closes: #1726
Approved by: pwithnall
2018-09-21 13:04:51 +00:00
Robert McQueen b32c9e0df9 OstreeMutableTree: add _remove method
There is no API method to remove a file or subdirectory from a MutableTree
besides directly manipulating the GHashTable returned by _get_files or
_get_subdirs. This isn't possible from an introspection binding that transforms
the returned GHashTable, and may also leave the tree checksum in an invalid
state. Introduce a new method so that removing files or subdirectories is
safe, and possible from bindings.

Closes: #1724
Approved by: jlebon
2018-09-20 17:49:55 +00:00
Matthew Leeds 6b37fe8310 lib/repo: Clean up OstreeRepo docs
This fixes typos and grammar in the docs for OstreeRepo, and copies the
information about OSTREE_REPO_MODE_BARE_USER_ONLY from ostree-core.h

Closes: #1725
Approved by: jlebon
2018-09-20 17:05:34 +00:00
Matthew Leeds e4e6d85ea4 avahi: Be robust to missing refs in peer summaries
In the OstreeRepoFinderAvahi implementation,
ostree_avahi_service_build_repo_finder_result() is where the DNS-SD
records are processed and turned into OstreeRepoFinderResult objects.
Each result object is supposed to have a hash table mapping refs to
checksums, so this is accomplished by first adding a placeholder (a ref
mapping to a NULL checksum) for each ref matched by the bloom filter,
and later filling in the checksums using the remote's summary file,
which happens in get_checksums(). The problem is that there's no
guarantee all the checksums will be resolved (non-NULL), so the
ostree_repo_finder_result_new() call then hits an assertion failure in
is_valid_collection_ref_map() leading to a crash (in the case that one
or more refs had NULL checksums).

There are at least two situations where the ref checksum might not be
found in the peer remote's summary file:
1) The bloom filter match was a false positive. This is going to happen
sometimes by design.
2) The peer remote's summary is out of sync with its DNS-SD records.
This shouldn't normally happen but it's still good to be robust to the
possibility; in Endless OS nothing guarantees the atomicity of updating
the summary and DNS-SD records.

This commit changes libostree to be robust to the possibility of refs
missing from the peer remote's summary, by removing any that still have
a NULL checksum associated with them after the summary has been fetched
and processed.

The other OstreeRepoFinder implementations don't have this issue because
they use summary files directly and therefore always have access to the
checksum.

Closes: #1717
Approved by: pwithnall
2018-09-07 10:19:24 +00:00
Umang Jain a70d2f6731 Add tests for ostree_repo_get_min_free_space_bytes
https://phabricator.endlessm.com/T23694

Closes: #1715
Approved by: cgwalters
2018-09-04 21:31:34 +00:00
Umang Jain 68420f70bb lib/repo: Add an API to get min-free-space-* reserved bytes
https://phabricator.endlessm.com/T23694

Closes: #1715
Approved by: cgwalters
2018-09-04 21:31:34 +00:00
Umang Jain 3814d075cb lib/repo: Ensure min-free-space* config value doesn't overflow
when converted to bytes

In a subsequent commit, we add a public API to read the value of
min-free-space-* value in bytes. The value for free space check
is enforced in terms of block size instead of bytes. Therefore,
for consistency we check while preparing the transaction that the
value doesn't overflow when converted to bytes.

https://phabricator.endlessm.com/T23694

Closes: #1715
Approved by: cgwalters
2018-09-04 21:31:33 +00:00
Felix Krull 74bdf7e173 lib/grub2: Support Debian-style grub.cfg path
Debian and Debian-derived systems have their GRUB configuration file in
/boot/grub/grub.cfg, rather than /boot/grub2/grub.cfg. Detecting this
file is necessary to correctly generate GRUB boot configuration on
Debian systems.

Closes: #1714
Approved by: cgwalters
2018-09-04 20:47:46 +00:00
Laurent Bonnans 630b786402 lib/fetcher: Fix some memory leaks in curl fetcher
Closes: #1716
Approved by: cgwalters
2018-08-31 11:02:41 +00:00
Simon McVittie 119b14e21d New upstream version 2018.8 2018-08-23 13:14:03 +01:00
Colin Walters 7aa242c34c Release 2018.8
Closes: #1705
Approved by: jlebon
2018-08-22 13:53:24 +00:00
Philip Withnall e7305bbc8a lib/repo-pull: Prefer object pull over from-scratch delta if ref exists
If a ref already exists, we are likely only a few commits behind the
current head of the ref, so it is probably better for bandwidth
consumption to pull the individual objects rather than the from-scratch
delta.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Closes: #1709
Approved by: cgwalters
2018-08-20 13:04:58 +00:00
Will Thompson 2b19869307 repo: remove outdated note from write_config() docs
Since 9dc6ddce08 it has not been true that
'new_config' was simply ref'd: it's serialized, and then re-parsed into
a new GKeyFile.

Closes: #1707
Approved by: jlebon
2018-08-19 02:01:12 +00:00
Dan Nicholson 4e6b13e8b6 repo: Add OSTREE_REPO_TEST_ERROR=invalid-cache env var
Add an invalid-cache test error flag to ensure that the code that checks
for and recovers from a corrupted summary cache is hit. This helps make
sure that the recovery path is actually used without resorting to
G_MESSAGES_DEBUG.

Closes: #1698
Approved by: cgwalters
2018-08-14 13:38:11 +00:00
Dan Nicholson e5061f54d6 lib/pull: Fetch summary if cached version doesn't match signature
If for some reason the cached summary doesn't match the cached signature
then fetch the remote summary and verify again. Since commit c4c2b5eb
this is unlikely to happen since the summary will only be cached if it
matches the signature. However, if the summary cache has been corrupted
for any other reason then it's best to be safe and fetch the remote
summary again.

This is essentially the corollary to c4c2b5eb. Where that commit helps
you from getting into the corrupted summary cache in the first place,
this helps you get out of it. Without this the client can get wedged
until a prune or the remote server republishes the summary.

Closes: #1698
Approved by: cgwalters
2018-08-14 13:38:11 +00:00
Dan Nicholson 1c69f1ed31 lib/pull: Add debug message when loading summary from cache
This helps when debugging issues with the cached summary handling.

Closes: #1698
Approved by: cgwalters
2018-08-14 13:38:11 +00:00
Alexander Larsson 0a53af801e ostree_repo_pull_from_remotes_async: Fix leak of options
copy_option() unnecessarily passed ownership of the value
to g_variant_dict_insert_value, but that already refs, so it was leaked.

Closes: #1702
Approved by: cgwalters
2018-08-14 12:49:28 +00:00
Alexander Larsson 24883db908 ostree_repo_static_delta_generate: Fix leak
There is no need to ref the argument of g_variant_builder_add_value

Closes: #1701
Approved by: jlebon
2018-08-13 17:50:33 +00:00
Alexander Larsson 016cae1573 Fix leak in ostree_repo_list_collection_refs
We need to have the g_auto(GLnxDirFdIterator) inside the loop, or
we don't correctly clean up when iterating several times.

Closes: #1700
Approved by: cgwalters
2018-08-13 16:29:59 +00:00
Jonathan Lebon 521e0ec3ac lib/commit: Only auto-update summary if refs were written
Closes: #1693
Approved by: mwleeds
2018-08-01 19:59:07 +00:00
Jonathan Lebon 72a54fa877 lib/config: Deprecate commit-update-summary option
Now that we have `auto-update-summary`, there is no point in having
`commit-update-summary`. The latter also only had an effect through
the `commit` CLI command, whereas the former is embedded directly in
libostree.

There is one corner case that slips through: `commit` would update the
summary file even if orphan commits were created, which we no longer do
here. I can't imagine anyone relying on this, so it seems safe to drop.

Closes: #1689

Closes: #1693
Approved by: mwleeds
2018-08-01 19:59:07 +00:00
Jonathan Lebon 786ee6bdec lib/config: Rename change-update-summary to auto-...
Mildly bikeshed, though I find the name `auto-update-summary` to be
easier to grok than `change-update-summary`. I think it's because it can
be read as "verb-verb-noun" rather than "noun-verb-noun".

Closes: #1693
Approved by: mwleeds
2018-08-01 19:59:07 +00:00
Jonathan Lebon 3e96ec9811 lib/refs: Use GLNX_HASH_TABLE_FOREACH_KV helper
Closes: #1693
Approved by: mwleeds
2018-08-01 19:59:07 +00:00
Matthew Leeds daa57b4630 lib/repo-pull: Use correct keyring for dynamic remotes
Normally, a configured remote will only serve refs with one associated
collection ID, but temporary remotes such as USB drives or LAN peers can
serve refs from multiple collection IDs which may use different GPG
keyrings. So the OstreeRepoFinderMount and OstreeRepoFinderAvahi classes
create dynamic OstreeRemote objects for each (uri, keyring) pair. So if
for example the USB mounted at /mnt/usb serves content from the
configured remotes "eos-apps" and "eos-sdk", the OstreeRepoFinderResult
array returned by ostree_repo_find_remotes_async() will have one result
with a remote called something like
file_mnt_usb_eos-apps.trustedkeys.gpg and the list of refs on the USB
that came from eos-apps, and another result with a remote
file_mnt_usb_eos-sdk.trustedkeys.gpg and the list of refs from eos-sdk.

Unfortunately while OstreeRepoFinderMount and OstreeRepoFinderAvahi
correctly only include refs in a result if the ref uses the associated
keyring, the find_remotes_cb() function used to clean up the set of
results looks at the remote summary file and includes every ref that's
in the intersection with the requested refs, regardless of whether it
uses a different remote's keyring. This leads to an error when you try
to pull from a USB containing refs from different collection IDs: the
pull using the wrong collection ID will error out with "Refspec not
found" and the result with the correct keyring will then be ignored "as
it has no relevant refs or they have already been pulled." So the pull
ultimately fails.

This commit fixes the issue by filtering refs coming from a dynamic
remote, so that only ones with the collection ID associated with the
keyring remote are examined. This only needs to be done for dynamic
remotes because you should be able to pull any ref from a configured
remote using its keyring. It's also only done when looking at the
collection map in the summary file, because LAN/USB remotes won't have a
"main" collection ID set (OSTREE_SUMMARY_COLLECTION_ID).

Closes: #1695
Approved by: pwithnall
2018-08-01 13:57:10 +00:00
Matthew Leeds 6869bada49 config: Add a core/change-update-summary option
This commits adds and implements a boolean repo config option called
"change-update-summary" which updates the summary file every time a ref
changes (additions, updates, and deletions).

The main impetus for this feature is that the `ostree create-usb` and
`flatpak create-usb` commands depend on the repo summary being up to
date. On the command line you can work around this by asking the user to
run `ostree summary --update` but in the case of GNOME Software calling
out to `flatpak create-usb` this wouldn't work because it's running as a
user and the repo is owned by root. That strategy also means flatpak
can't update the repo metadata refs for fear of invalidating the
summary.

Another use case for this relates to LAN updates. Specifically, the
component of eos-updater that generates DNS-SD records advertising ostree
refs depends on the repo summary being up to date.

Since ostree_repo_regenerate_summary() now takes an exclusive lock, this
should be safe to enable. However it's not enabled by default because of
the performance cost, and because it's more useful on clients than
servers (which likely have another mechanism for updating the summary).

Fixes https://github.com/ostreedev/ostree/issues/1664

Closes: #1681
Approved by: jlebon
2018-07-30 17:19:12 +00:00
Matthew Leeds fb36b62f33 lib/repo: Take exclusive lock while generating summary
This ensures that commits aren't deleted and refs aren't added, removed,
or updated while the summary is being generated. This is in preparation
for adding a repo config option that will automatically regenerate the
summary on every ref change.

Closes: #1681
Approved by: jlebon
2018-07-30 17:19:12 +00:00