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[PATCH v2 2/3] job: take each job's lock individually in job_txn_apply
From: |
Stefan Reiter |
Subject: |
[PATCH v2 2/3] job: take each job's lock individually in job_txn_apply |
Date: |
Thu, 26 Mar 2020 16:56:27 +0100 |
All callers of job_txn_apply hold a single job's lock, but different
jobs within a transaction can have different contexts, thus we need to
lock each one individually before applying the callback function.
Similar to job_completed_txn_abort this also requires releasing the
caller's context before and reacquiring it after to avoid recursive
locks which might break AIO_WAIT_WHILE in the callback.
Signed-off-by: Stefan Reiter <address@hidden>
---
job.c | 32 ++++++++++++++++++++++++--------
1 file changed, 24 insertions(+), 8 deletions(-)
diff --git a/job.c b/job.c
index 134a07b92e..e0966162fa 100644
--- a/job.c
+++ b/job.c
@@ -136,17 +136,33 @@ static void job_txn_del_job(Job *job)
}
}
-static int job_txn_apply(JobTxn *txn, int fn(Job *))
+static int job_txn_apply(Job *job, int fn(Job *))
{
- Job *job, *next;
+ AioContext *outer_ctx = job->aio_context;
+ AioContext *inner_ctx;
+ Job *other_job, *next;
+ JobTxn *txn = job->txn;
int rc = 0;
- QLIST_FOREACH_SAFE(job, &txn->jobs, txn_list, next) {
- rc = fn(job);
+ /*
+ * Similar to job_completed_txn_abort, we take each job's lock before
+ * applying fn, but since we assume that outer_ctx is held by the caller,
+ * we need to release it here to avoid holding the lock twice - which would
+ * break AIO_WAIT_WHILE from within fn.
+ */
+ aio_context_release(outer_ctx);
+
+ QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
+ inner_ctx = other_job->aio_context;
+ aio_context_acquire(inner_ctx);
+ rc = fn(other_job);
+ aio_context_release(inner_ctx);
if (rc) {
break;
}
}
+
+ aio_context_acquire(outer_ctx);
return rc;
}
@@ -774,11 +790,11 @@ static void job_do_finalize(Job *job)
assert(job && job->txn);
/* prepare the transaction to complete */
- rc = job_txn_apply(job->txn, job_prepare);
+ rc = job_txn_apply(job, job_prepare);
if (rc) {
job_completed_txn_abort(job);
} else {
- job_txn_apply(job->txn, job_finalize_single);
+ job_txn_apply(job, job_finalize_single);
}
}
@@ -824,10 +840,10 @@ static void job_completed_txn_success(Job *job)
assert(other_job->ret == 0);
}
- job_txn_apply(txn, job_transition_to_pending);
+ job_txn_apply(job, job_transition_to_pending);
/* If no jobs need manual finalization, automatically do so */
- if (job_txn_apply(txn, job_needs_finalize) == 0) {
+ if (job_txn_apply(job, job_needs_finalize) == 0) {
job_do_finalize(job);
}
}
--
2.26.0
- [PATCH v2 0/3] Fix some AIO context locking in jobs, Stefan Reiter, 2020/03/26
- [PATCH v2 2/3] job: take each job's lock individually in job_txn_apply,
Stefan Reiter <=
- [PATCH v2 3/3] replication: acquire aio context before calling job_cancel_sync, Stefan Reiter, 2020/03/26
- [PATCH v2 1/3] backup: don't acquire aio_context in backup_clean, Stefan Reiter, 2020/03/26
- Re: [PATCH v2 0/3] Fix some AIO context locking in jobs, no-reply, 2020/03/26
- Re: [PATCH v2 0/3] Fix some AIO context locking in jobs, no-reply, 2020/03/26
- Re: [PATCH v2 0/3] Fix some AIO context locking in jobs, Dietmar Maurer, 2020/03/27
- Re: [PATCH v2 0/3] Fix some AIO context locking in jobs, Dietmar Maurer, 2020/03/27