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[Qemu-devel] [PATCH] job: Fix nested aio_poll() hanging in job_txn_apply
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [PATCH] job: Fix nested aio_poll() hanging in job_txn_apply |
Date: |
Tue, 21 Aug 2018 14:45:38 +0800 |
All callers have acquired ctx already. Doing that again results in
aio_poll() hang. This fixes the problem that a BDRV_POLL_WHILE() in the
callback cannot make progress because ctx is recursively locked, for
example, when drive-backup finishes.
Cc: address@hidden
Reported-by: Gu Nini <address@hidden>
Signed-off-by: Fam Zheng <address@hidden>
---
job.c | 18 +++++-------------
1 file changed, 5 insertions(+), 13 deletions(-)
diff --git a/job.c b/job.c
index fa671b431a..b07c5d0ffc 100644
--- a/job.c
+++ b/job.c
@@ -136,21 +136,13 @@ static void job_txn_del_job(Job *job)
}
}
-static int job_txn_apply(JobTxn *txn, int fn(Job *), bool lock)
+static int job_txn_apply(JobTxn *txn, int fn(Job *))
{
- AioContext *ctx;
Job *job, *next;
int rc = 0;
QLIST_FOREACH_SAFE(job, &txn->jobs, txn_list, next) {
- if (lock) {
- ctx = job->aio_context;
- aio_context_acquire(ctx);
- }
rc = fn(job);
- if (lock) {
- aio_context_release(ctx);
- }
if (rc) {
break;
}
@@ -807,11 +799,11 @@ static void job_do_finalize(Job *job)
assert(job && job->txn);
/* prepare the transaction to complete */
- rc = job_txn_apply(job->txn, job_prepare, true);
+ rc = job_txn_apply(job->txn, job_prepare);
if (rc) {
job_completed_txn_abort(job);
} else {
- job_txn_apply(job->txn, job_finalize_single, true);
+ job_txn_apply(job->txn, job_finalize_single);
}
}
@@ -857,10 +849,10 @@ static void job_completed_txn_success(Job *job)
assert(other_job->ret == 0);
}
- job_txn_apply(txn, job_transition_to_pending, false);
+ job_txn_apply(txn, job_transition_to_pending);
/* If no jobs need manual finalization, automatically do so */
- if (job_txn_apply(txn, job_needs_finalize, false) == 0) {
+ if (job_txn_apply(txn, job_needs_finalize) == 0) {
job_do_finalize(job);
}
}
--
2.17.1
- [Qemu-devel] [PATCH] job: Fix nested aio_poll() hanging in job_txn_apply,
Fam Zheng <=