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[Qemu-block] [PATCH v2] qemu-img: fix in-flight count for qemu-img bench
From: |
Paolo Bonzini |
Subject: |
[Qemu-block] [PATCH v2] qemu-img: fix in-flight count for qemu-img bench |
Date: |
Wed, 7 Dec 2016 16:08:27 +0100 |
With aio=native (qemu-img bench -n) one or more requests can be completed
when a new request is submitted. This in turn can cause bench_cb to
recurse before b->in_flight is updated. This causes multiple I/Os
to be submitted with the same offset and, furthermore, the blk_aio_*
coroutines are never freed and qemu-img aborts.
Signed-off-by: Paolo Bonzini <address@hidden>
---
qemu-img.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/qemu-img.c b/qemu-img.c
index 6949b73..5df66fe 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -3559,20 +3559,23 @@ static void bench_cb(void *opaque, int ret)
}
while (b->n > b->in_flight && b->in_flight < b->nrreq) {
+ int64_t offset = b->offset;
+ /* blk_aio_* might look for completed I/Os and kick bench_cb
+ * again, so make sure this operation is counted by in_flight
+ * and b->offset is ready for the next submission.
+ */
+ b->in_flight++;
+ b->offset += b->step;
+ b->offset %= b->image_size;
if (b->write) {
- acb = blk_aio_pwritev(b->blk, b->offset, b->qiov, 0,
- bench_cb, b);
+ acb = blk_aio_pwritev(b->blk, offset, b->qiov, 0, bench_cb, b);
} else {
- acb = blk_aio_preadv(b->blk, b->offset, b->qiov, 0,
- bench_cb, b);
+ acb = blk_aio_preadv(b->blk, offset, b->qiov, 0, bench_cb, b);
}
if (!acb) {
error_report("Failed to issue request");
exit(EXIT_FAILURE);
}
- b->in_flight++;
- b->offset += b->step;
- b->offset %= b->image_size;
}
}
--
2.9.3
- [Qemu-block] [PATCH v2] qemu-img: fix in-flight count for qemu-img bench,
Paolo Bonzini <=