debian/patches/pve/0029-PVE-Add-sequential-job-transaction-support.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Stefan Reiter <s.reiter@proxmox.com>
   3 Date: Thu, 20 Aug 2020 14:31:59 +0200
   4 Subject: [PATCH] PVE: Add sequential job transaction support
   5
   6 Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
   7 Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
   8 ---
   9  include/qemu/job.h | 12 ++++++++++++
  10  job.c              | 34 ++++++++++++++++++++++++++++++++++
  11  2 files changed, 46 insertions(+)
  12
  13 diff --git a/include/qemu/job.h b/include/qemu/job.h
  14 index e502787dd8..963cf2bef5 100644
  15 --- a/include/qemu/job.h
  16 +++ b/include/qemu/job.h
  17 @@ -381,6 +381,18 @@ void job_unlock(void);
  18   */
  19  JobTxn *job_txn_new(void);
  20
  21 +/**
  22 + * Create a new transaction and set it to sequential mode, i.e. run all jobs
  23 + * one after the other instead of at the same time.
  24 + */
  25 +JobTxn *job_txn_new_seq(void);
  26 +
  27 +/**
  28 + * Helper method to start the first job in a sequential transaction to kick it
  29 + * off. Other jobs will be run after this one completes.
  30 + */
  31 +void job_txn_start_seq(JobTxn *txn);
  32 +
  33  /**
  34   * Release a reference that was previously acquired with job_txn_add_job or
  35   * job_txn_new. If it's the last reference to the object, it will be freed.
  36 diff --git a/job.c b/job.c
  37 index 93e22d180b..2b31f1e14f 100644
  38 --- a/job.c
  39 +++ b/job.c
  40 @@ -93,6 +93,8 @@ struct JobTxn {
  41
  42      /* Reference count */
  43      int refcnt;
  44 +
  45 +    bool sequential;
  46  };
  47
  48  void job_lock(void)
  49 @@ -118,6 +120,25 @@ JobTxn *job_txn_new(void)
  50      return txn;
  51  }
  52
  53 +JobTxn *job_txn_new_seq(void)
  54 +{
  55 +    JobTxn *txn = job_txn_new();
  56 +    txn->sequential = true;
  57 +    return txn;
  58 +}
  59 +
  60 +void job_txn_start_seq(JobTxn *txn)
  61 +{
  62 +    assert(txn->sequential);
  63 +    assert(!txn->aborting);
  64 +
  65 +    Job *first = QLIST_FIRST(&txn->jobs);
  66 +    assert(first);
  67 +    assert(first->status == JOB_STATUS_CREATED);
  68 +
  69 +    job_start(first);
  70 +}
  71 +
  72  /* Called with job_mutex held. */
  73  static void job_txn_ref_locked(JobTxn *txn)
  74  {
  75 @@ -1057,6 +1078,12 @@ static void job_completed_txn_success_locked(Job *job)
  76       */
  77      QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
  78          if (!job_is_completed_locked(other_job)) {
  79 +            if (txn->sequential) {
  80 +                job_unlock();
  81 +                /* Needs to be called without holding the job lock */
  82 +                job_start(other_job);
  83 +                job_lock();
  84 +            }
  85              return;
  86          }
  87          assert(other_job->ret == 0);
  88 @@ -1268,6 +1295,13 @@ int job_finish_sync_locked(Job *job,
  89          return -EBUSY;
  90      }
  91
  92 +    /* in a sequential transaction jobs with status CREATED can appear at time
  93 +     * of cancelling, these have not begun work so job_enter won't do anything,
  94 +     * let's ensure they are marked as ABORTING if required */
  95 +    if (job->status == JOB_STATUS_CREATED && job->txn->sequential) {
  96 +        job_update_rc_locked(job);
  97 +    }
  98 +
  99      job_unlock();
 100      AIO_WAIT_WHILE_UNLOCKED(job->aio_context,
 101                              (job_enter(job), !job_is_completed(job)));