Gerrit Workflow
We're using Gerrit for code inspections and for managing changes to branches. The workflow for a change in Gerrit begins with an inspection request, and once the request has been approved, it is pushed directly to the branch by the gatekeeper. We don't need to manage patches externally, or manage our landing process using other tools - all of it can be done in Gerrit. Please review the Using Gerrit page for more details on how Gerrit and Git are used together.
Requirements for patch submission
All patches that land on the main release branches in the fs/lustre-release repository must conform to the Lustre Coding Guidelines, pass the standard Lustre regression tests. All patches should be associated with a Lustre Jira ticket, and by signed off by the developer. Bug fixes should include additional regression tests. Feature patches should include new regression tests to exercise the feature, and potentially performance or load tests as appropriate for the change. All changes submitted to the fs/lustre-release repository will be tested automatically with the Lustre regression tests in lustre/tests and a link to the test results (saved in Maloo) and a pass/fail review comment will be added to the Gerrit change. For additional tests run outside of autotest, the results can either be sent to Maloo manually, or test results can be posted into the Jira ticket associated with the patch.
If there are a series of changes being made to the code (e.g. code style fixes, renaming some functions, adding function parameters, moving code from one file to another, making the actual fix for a bug, making some additional fixes to other defects found during coding), these should all go into separate patches for inspection and testing. Having a series of smaller patches, each of which makes a single, clearly understood change speeds up inspection significantly. Ordering uncontroversial and easy-to-inspect changes first in a patch series ensures that they are only inspected a single time, and can land quickly. Ordering complex changes at the end of the patch series ensures that if changes are requested by the inspectors for these patches, the earlier ones do not need to be re-inspected and re-tested for each update. Following this patch submission model speeds up patch landing, and reduces the burden on the patch inspector, and test systems, and reduces the time that the patch submitter needs to spend waiting or rebasing in order to get their patches accepted.
If there are a number of patches on a git branch, pushing the changes to Gerrit will result in the entire series of patches being sent, with a separate change for each patch. Gerrit correctly tracks dependencies for these patches. If the patches are rebased, either on a new Lustre version, or one of the earlier patches in the series is modified, then all modified patches will be resubmitted to Gerrit for re-inspection, build, and testing.
Any patches that require updates to the Lustre manual will also need to submit documentation updates when the patch is ready for submission. See the link Making changes to the Lustre Manual.
For code that requires modifications or additions to the existing suite of automated Lustre tests, the new or modified test scripts must be submitted with the patch. If there is a defect in the existing code, it means that there is no regression test that covers this code path. A new test should be written that confirms the problem be hit by the test before the fix is landed, and verifies the patch resolves the problem afterward. Any additional testing that cannot be covered by the existing automated Lustre tests must also be documented with a clear, step-by-step test plan, and arrangements must be made with the Lustre test team to execute these plans.
Signed-off-by
We are using the a similar sign-off process that is used for contributions to the Linux kernel. This means developers making contributions certify that they wrote the patch or have the right to pass it on. To certify this, you include a Signed-off-by: line like this one at the bottom of your commit comments:
Signed-off-by: Random J Developer <random@developer.example.org>
Adding this line means that you certify the following:
Developer's Certificate of Origin 1.1
By making a contribution to this project, I certify that:
(a) The contribution was created in whole or in part by me and I
have the right to submit it under the open source license
indicated in the file; or
(b) The contribution is based upon previous work that, to the best
of my knowledge, is covered under an appropriate open source
license and I have the right under that license to submit that
work with modifications, whether created in whole or in part
by me, under the same open source license (unless I am
permitted to submit under a different license), as indicated
in the file; or
(c) The contribution was provided directly to me by some other
person who certified (a), (b) or (c) and I have not modified
it.
(d) I understand and agree that this project and the contribution
are public and that a record of the contribution (including all
personal information I submit with it, including my sign-off) is
maintained indefinitely and may be redistributed consistent with
this project or the open source license(s) involved.
Changes submitted to to the release branch without the Signed-off-by: line will be rejected.
Commit comment format
The first line of the commit comment is the commit summary of the change. Changes submitted to the fs/lustre-release branch also require a Lustre Jira issue tag at the beginning of the first line of the commit summary. A Lustre Jira ticket is one that begins with LU and is therefore part of the Lustre project within Jira. If the patch is submitted for the fs/lustre-release repository without a Lustre Jira ID in the first line, then it will automatically receive a -2 review which will prevent the patch from being submitted to a release branch. You will get an e-mail about this rejection at which time you can add the line and resubmit the patch. The commit summary should also have a component: field immediately following the Jira issue tag that indicates which Lustre subsystem that the commit is related to. Example Lustre subsystems relate to modules like llite, lov, osc, mdc, lmv, ldlm, ptlrpc, mds, oss, mdd, osd, ldiskfs, lnet, libcfs, socklnd, o2iblnd; functional components like recovery, quota, grant; or auxiliary components like build, tests, docs. This subsystem list is not exhaustive, but provides a good guideline for consistency.
The rest of the comments should be wrapped to 70 columns or less. This allows for the first line to be used a subject in emails, and also for the entire body to be displayed using tools like git log or git shortlog in an 80 column window.
Please make sure the Change-Id: line and Signed-off-by: lines are at the bottom of the comment. This is required by the fs/lustre-release project (at least) in order for the patch to be approved. If your comments are missing either of these lines the patch will be automatically be rejected at submission time. See Using Gerrit for a description of the Change-Id: line .
Example comment
LU-999 component: short description of change under 64 columns A more detailed explanation. This can be as detailed as you'd like. Please explain both what problem was solved and a good high-level description of how it was solved. Wrap lines at 72 columns or less. Signed-off-by: Random J Developer <random@developer.example.org> Change-Id: Ica9ed1612eab0c4673dee088f8b441d806c64932
An example of a good commit comments are:
LU-477 ldiskfs: allocate s_group_desc/s_group_info by vmalloc()
Add the patch to the RHEL6 ldiskfs patch series.
Large kmalloc() for sbi->s_group_desc and sbi->s_group_info can fail
for large filesystems, which will cause the "not enough memory" error
while mounting. This patch makes it fall back to vmalloc() if the
kmalloc() failed, as what was done for sbi->s_flex_groups.
To avoid colliding with an valid on-disk inode number, EXT4_BAD_INO
is used as the number of the buddy cache inode.
The patch also incorporates the following upstream kernel fix:
commit 32a9bb57d7c1fd04ae0f72b8f671501f000a0e9f
ext4: fix missing iput of root inode for some mount error paths
https://bugzilla.kernel.org/show_bug.cgi?id=26752
LU-64 utils: make "lfs getstripe" directory output consistent.
"lfs getstripe" should report the global default for any fields with
a value that means "use the default". This patch introduces the
following functionality:
1. If "lfs getstripe" is called on a directory and finds that striping
EA is not set, the filesystem's defaults are looked up and printed.
2. If the striping EA is set, but the striping count and/or striping
size has a value that means "use the default" (count = 0 and/or
size = 0), the filesystem's default for that specific striping
attribute is looked up and printed.
3. A new option to "lfs getstripe" is introduced; the "--raw" or
"-R" option. If this option is specified, the previous two checks
are skipped. In other words, if the striping EA is not set, 0, 0,
-1, will be printed for the striping count, size, and offset
respectively. Also, if the striping EA is set, the values will be
printed without first converting them into their respective
defaults.
This patch relies on the /proc filesystem to determine each
filesystem's default striping attributes, and a cache is maintained
which holds the default values for the last filesystem queried.
See Also:
Bugzilla #23802, https://bugzilla.lustre.org/show_bug.cgi?id=23802
Submitting a change to a Lustre Release
The git URLs here assume you have updated your ~/.ssh/config using the suggestions in Using Gerrit.
The repository we are using for releases is fs/lustre-release. This is the repository to push to when you request an inspection for a change that is ready for a release. There are currently only two branches here, b1_8 and master, which is the branch for 2.X releases.
git clone ssh://review/fs/lustre-release
Push the change to the fs/lustre-release repository for inspection and eventual submission to the master branch:
git push origin HEAD:refs/for/master
Once a change request has received at least two positive inspections (and ideally no negatives), the gatekeeper for the branch will, at her discretion, submit the change directly from Gerrit. If a patch no longer applies cleanly to the branch, then it will need to be updated by the developer, and the gatekeeper should be notified when the patch is ready again. The gatekeeper will decide if additional inspections are required or if it is ready to land.
Patch landing process
Brief summary for landing patch to lustre in Whamcloud:
- Test and commit your patch locally.
- Verify patch follows Lustre Coding Guidelines with
git show | build/checkpatch.pl - - Push your patch to Gerrit for inspection, and request at least two inspectors (preferably with experience in this area of code).
- Test your patch on real cluster and upload your test results to Maloo.
- Add a comment on Gerrit with the Maloo link to indicate that the patch works, and set the
Verifiedflag. - Add the branch gatekeeper as inspector on Gerrit to notify him/her that the patch is ready.
- The branch gatekeeper will review the patch, confirm the test results, and submit it when everything goes well.
- If the submission failed due to conflict(s), the gatekeeper will ask you to rebase your patch with the target branch and repeat above steps.
- If your patch is useful for other branch(es), please repeat above steps against corresponding branch(es).
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