curl_multi_check_completion would bail upon the first completed
transfer even if more completion messages were available thus leaving
some in flight IOs stuck.
Rework a bit the loop to make the iterations clearer and drop the breaks.
The original hang can be somewhat reproduced with the following command:
$ qemu-img convert -p -m 16 -O qcow2 -c --image-opts \
'file.driver=https,file.url=https://scaleway.testdebit.info/10G.iso,file.readahead=1M' \
/tmp/test.qcow2
Fixes: 1f2cead32443 ("curl: Ensure all informationals are checked for completion")
Cc: qemu-stable@nongnu.org
Signed-off-by: Antoine Damhet <adamhet@scaleway.com>
---
block/curl.c | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/block/curl.c b/block/curl.c
index 4e77c93b46e6..6dccf002564e 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -324,17 +324,11 @@ curl_find_buf(BDRVCURLState *s, uint64_t start, uint64_t len, CURLAIOCB *acb)
static void curl_multi_check_completion(BDRVCURLState *s)
{
int msgs_in_queue;
+ CURLMsg *msg;
/* Try to find done transfers, so we can free the easy
* handle again. */
- for (;;) {
- CURLMsg *msg;
- msg = curl_multi_info_read(s->multi, &msgs_in_queue);
-
- /* Quit when there are no more completions */
- if (!msg)
- break;
-
+ while ((msg = curl_multi_info_read(s->multi, &msgs_in_queue))) {
if (msg->msg == CURLMSG_DONE) {
int i;
CURLState *state = NULL;
@@ -397,7 +391,6 @@ static void curl_multi_check_completion(BDRVCURLState *s)
}
curl_clean_state(state);
- break;
}
}
}
--
2.53.0