Ceph » Stable releases

h3. Backport commits

General guidelines:

- backports should be done by cherry-picking commits that are in master, and in the most minimal way possible - see [[HOWTO_review_backport_PRs]] for more information

- it should be clear which bug the backport is fixing

- features can be backported only with permission from the relevant lead

- the tracker issue should state why the backport is necessary

Detailed instructions:

* Pick one entry with the highest *Priority* field in the list of backports linked from [[HOWTO|the top level page]] (for instance "hammer backports":http://tracker.ceph.com/projects/ceph/issues?query_id=78)

* Assign the issue to yourself (or add a comment if you do not have permission) so that people know you start working on it.

* <code>git clone</code> a fork of http://github.com/ceph/ceph

* <code>git checkout -b wip-$issue-$release origin/$release</code> to create a branch with a name that reflects the issue being fixed and the target release: this naming is convenient to select all branches containing backports for firefly or select all branches containing backports for a specific issue

* <code>git cherry-pick -x</code> the commits from the pull request that was targeting <code>master</code> (not from the pull requests targeting stable branches -- with the exception of the upcoming stable branch, which can be used because all commits to the upcoming stable branch are merged into <code>master</code> on a regular basis)

** the original issue is linked in the *Related issues* section of the issue, as a *Copied from* link

** the pull request or commit targeting master can be found by following the *Copied from* link and searching the original issue

** TIP: if the cherry-pick fails due to whitespace differences, use <code>-Xignore-all-space</code>

* <code>git push origin wip-$issue-$release</code> to publish the branch on github and be able to create a pull request from it

* generate a *$github_token* by "following the GitHub instructions":https://help.github.com/articles/creating-an-access-token-for-command-line-use/

* retrieve the *$redmine_key*: it is a token that will allow you to script issue updates

** login http://tracker.ceph.com/

** visit http://tracker.ceph.com/my/account

** look for *API access key* in the page (Control-f)

** click on the *Show* link just under *API access key*

** copy the hexadecimal number it shows

** redmine_key=b586ce6a7a936e71f351c93ac0b65a588d4333

* create a pull request from the <code>wip-$issue-$release</code> branch with the same title as the issue

<pre>

account=myaccount

eval title=$(curl --silent 'http://tracker.ceph.com/issues/'$issue.json?key=$redmine_key | jq .issue.subject) ; echo $title

number=$(curl --silent --data-binary '{"title":"'"$title"'","head":"'$account':wip-'$issue-$release'","base":"'$release'","body":"http://tracker.ceph.com/issues/'$issue'"}' 'https://api.github.com/repos/ceph/ceph/pulls?access_token='$github_token | jq .number)

</pre>

* assigned the pull request to yourself (because it needs to got through integration tests before it can be approved by the original author), add the relevant labels (rgw, core, bug fix, feature...) and set the milestone to $release (requires write permission to the ceph repository)

<pre>

component=core ; curl --silent --data-binary '{"milestone":"'$release_number'","assignee":"'$account'","labels":["bug fix","'$component'"]}' 'https://api.github.com/repos/ceph/ceph/issues/'$number'?access_token='$github_token

</pre>

* wait for the make check bot to run the *run-make-check.sh* script on the branch that was pushed and verify it works

* Set the issue description to only contain the URL to the pull request and change the status to *In Progress*

<pre>

redmine_status=2 # In Progress

curl --verbose -X PUT --header 'Content-type: application/json' --data-binary '{"issue":{"description":"https://github.com/ceph/ceph/pull/'$number'","status_id":'$redmine_status'}}' 'http://tracker.ceph.com/issues/'$issue.json?key=$redmine_key

</pre>

* if there is a conflict explain how it was resolved in the commit message, below the Conflicts line. For instance:

<pre>

commit c60da2f3c34e7325c748d2d6e55140a0a30013fd

Author: Samuel Just <sjust@redhat.com>

Date:   Thu Nov 20 15:15:08 2014 -0800

    PGLog: include rollback_info_trimmed_to in (read|write)_log

    Fixes: #10157

    Backport: firefly, giant

    Signed-off-by: Samuel Just <sjust@redhat.com>

    (cherry picked from commit 1fe8b846641486cc294fe7e1d2450132c38d2dba)

    Conflicts:

    	src/osd/PGLog.cc

            in the context coll_t::META_COLL was replaced with META_COLL

</pre>

* The difference between the original commit and the one including a conflict resolution can be displayed with

<pre>

commit=c7d0d51cb574594de6f09457c960347b11fc2474 ; picked_from=$(git show --no-patch --pretty=%b $commit  |  perl -ne 'print if(s/.*cherry picked from commit (\w+).*/$1/)') ; diff -u --ignore-matching-lines '^[^+-]' <(git show $picked_from) <(git show $commit)

</pre>

* if the conflict is difficult to resolve, seek help from the author of the original commit (see "librbd: deadlock in image refresh":https://github.com/ceph/ceph/pull/4176 for instance) and assign the issue to her/him, or to a [[HOWTO#Leads|lead]]

Do not merge the pull request yet. Merging only takes place after the backports pass [[HOWTO run integration and upgrade tests|integration and upgrade tests]] and with proper approval as described in [[HOWTO merge commits from the integration branch]].

When the backport PR is opened, you can update the backport tracker issue: set *Status* to "In Progress" and *Target version* to the version you are working on.

All commits being backported must be cherry-picked from master. There are exceptions to this rule (see https://github.com/ceph/ceph/pull/4175 for instance: it fixes a regression introduced by an incorrect resolution of a backport) but they are rare. When a backport is done to fix a bug that shows in the integration tests or upgrade tests run by cron, testing the backport in an integration branch is redundant because the existing tests will keep failing.

Here are the snippets above grouped together for easier copy/paste:

<pre>

set -x

redmine_key=b586c588d4333

redmine_user_id=789 # as found in the URL near "Logged in as " top right of each page

github_token=bc275830c635

github_user=dachary

issue=$1

# can't seem to extract the release number with the api

release=giant ; release_number=2

release=firefly ; release_number=3

release=hammer ; release_number=5

release=infernalis ; release_number=7

if [ $(curl --silent http://tracker.ceph.com/issues/$issue.json | jq -r .issue.tracker.name) != "Backport" ]

then

    echo "not a backport issue"

    exit 1

fi

git checkout -f -b wip-$issue-$release ceph/$release

git cherry-pick -x .....

git push loic wip-$issue-$release ; sleep 2 # let github catch up

title=$(curl --silent 'http://tracker.ceph.com/issues/'$issue.json?key=$redmine_key | jq .issue.subject | tr -d '\\"')

echo "Issue title: $title"

number=$(curl --silent --data-binary '{"title":"'"$title"'","head":"'$github_user':wip-'$issue-$release'","base":"'$release'","body":"http://tracker.ceph.com/issues/'$issue'"}' 'https://api.github.com/repos/ceph/ceph/pulls?access_token='$github_token | jq .number)

echo "Opened pull request $number"

component=core ; curl --silent --data-binary '{"milestone":"'$release_number'","assignee":"'$github_user'","labels":["bug fix","'$component'"]}' 'https://api.github.com/repos/ceph/ceph/issues/'$number'?access_token='$github_token

firefox https://github.com/ceph/ceph/pull/$number

redmine_status=2 # In Progress

curl --verbose -X PUT --header 'Content-type: application/json' --data-binary '{"issue":{"description":"https://github.com/ceph/ceph/pull/'$number'","status_id":'$redmine_status',"assigned_to_id":'$redmine_user_id'}}' 'http://tracker.ceph.com/issues/'$issue.json?key=$redmine_key

firefox http://tracker.ceph.com/issues/$issue

</pre>

If you would like to automate update of the tracker target version, try something like this instead of the last <code>curl</code> command:

<pre>

curl --verbose -X PUT --header 'Content-type: application/json' --data-binary '{"issue":{"description":"https://github.com/ceph/ceph/pull/'$number'","status_id":'$redmine_status',"fixed_version_id":'$redmine_fixed_version'}}' 'http://tracker.ceph.com/issues/'$issue.json?key=$redmine_key

</pre>

The values of <code>$redmine_status</code> and <code>$redmine_fixed_version</code> can be determined by setting the desired values in an issue and then peeking at the JSON using a command like this:

<pre>

curl --silent 'http://tracker.ceph.com/issues/12395.json'

</pre>