debian/patches/pve/0042-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 ---
   8  include/qemu/job.h | 12 ++++++++++++
   9  job.c              | 31 +++++++++++++++++++++++++++++++
  10  2 files changed, 43 insertions(+)
  11
  12 diff --git a/include/qemu/job.h b/include/qemu/job.h
  13 index 32aabb1c60..f7a6a0926a 100644
  14 --- a/include/qemu/job.h
  15 +++ b/include/qemu/job.h
  16 @@ -280,6 +280,18 @@ typedef enum JobCreateFlags {
  17   */
  18  JobTxn *job_txn_new(void);
  19
  20 +/**
  21 + * Create a new transaction and set it to sequential mode, i.e. run all jobs
  22 + * one after the other instead of at the same time.
  23 + */
  24 +JobTxn *job_txn_new_seq(void);
  25 +
  26 +/**
  27 + * Helper method to start the first job in a sequential transaction to kick it
  28 + * off. Other jobs will be run after this one completes.
  29 + */
  30 +void job_txn_start_seq(JobTxn *txn);
  31 +
  32  /**
  33   * Release a reference that was previously acquired with job_txn_add_job or
  34   * job_txn_new. If it's the last reference to the object, it will be freed.
  35 diff --git a/job.c b/job.c
  36 index f9884e7d9d..05b7797e82 100644
  37 --- a/job.c
  38 +++ b/job.c
  39 @@ -72,6 +72,8 @@ struct JobTxn {
  40
  41      /* Reference count */
  42      int refcnt;
  43 +
  44 +    bool sequential;
  45  };
  46
  47  /* Right now, this mutex is only needed to synchronize accesses to job->busy
  48 @@ -102,6 +104,25 @@ JobTxn *job_txn_new(void)
  49      return txn;
  50  }
  51
  52 +JobTxn *job_txn_new_seq(void)
  53 +{
  54 +    JobTxn *txn = job_txn_new();
  55 +    txn->sequential = true;
  56 +    return txn;
  57 +}
  58 +
  59 +void job_txn_start_seq(JobTxn *txn)
  60 +{
  61 +    assert(txn->sequential);
  62 +    assert(!txn->aborting);
  63 +
  64 +    Job *first = QLIST_FIRST(&txn->jobs);
  65 +    assert(first);
  66 +    assert(first->status == JOB_STATUS_CREATED);
  67 +
  68 +    job_start(first);
  69 +}
  70 +
  71  static void job_txn_ref(JobTxn *txn)
  72  {
  73      txn->refcnt++;
  74 @@ -841,6 +862,9 @@ static void job_completed_txn_success(Job *job)
  75       */
  76      QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
  77          if (!job_is_completed(other_job)) {
  78 +            if (txn->sequential) {
  79 +                job_start(other_job);
  80 +            }
  81              return;
  82          }
  83          assert(other_job->ret == 0);
  84 @@ -1011,6 +1035,13 @@ int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp)
  85          return -EBUSY;
  86      }
  87
  88 +    /* in a sequential transaction jobs with status CREATED can appear at time
  89 +     * of cancelling, these have not begun work so job_enter won't do anything,
  90 +     * let's ensure they are marked as ABORTING if required */
  91 +    if (job->status == JOB_STATUS_CREATED && job->txn->sequential) {
  92 +        job_update_rc(job);
  93 +    }
  94 +
  95      AIO_WAIT_WHILE(job->aio_context,
  96                     (job_enter(job), !job_is_completed(job)));
  97