[libvirt] [PATCH] virsh: improve waiting for block job readiness
Wait for a block job event after the job has reached 100% only if
exactly one of the BLOCK_JOB and BLOCK_JOB_2 callbacks were successfully
registered.
If neither callback was registered, then no event will ever be received.
If both were registered, then any user-supplied path is guaranteed to
match one of the events.
Signed-off-by: Michael Chapman <mike(a)very.puzzling.org>
---
I have found that even a 2.5 second timeout isn't always sufficiently
long for QEMU to flush a disk at the end of a block job.
I hope I've understood the code properly here, because as far as I can
tell the comment I'm removing in this commit isn't right. The path the
user supplies *has* to be either the <source file='name'/> or <target
dev='name'/> exactly in order for the disk to be matched, and these are
precisely the two strings used by the two events.
tools/virsh-domain.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index edbbc34..60de9ba 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -1942,18 +1942,20 @@ virshBlockJobWait(virshBlockJobWaitDataPtr data)
goto cleanup;
}
- /* since virsh can't guarantee that the path provided by the user will
- * later be matched in the event we will need to keep the fallback
- * approach and claim success if the block job finishes or vanishes. */
- if (result == 0)
- break;
+ /* if either event could not be registered we can't guarantee that the
+ * path provided by the user will be matched, so keep the fallback
+ * approach and claim success if the block job finishes or vanishes */
+ if (data->cb_id2 < 0 || data->cb_id2 < 0) {
+ if (result == 0)
+ break;
- /* for two-phase jobs we will try to wait in the synchronized phase
- * for event arrival since 100% completion doesn't necessarily mean that
- * the block job has finished and can be terminated with success */
- if (info.end == info.cur && --retries == 0) {
- ret = VIR_DOMAIN_BLOCK_JOB_READY;
- goto cleanup;
+ /* only wait in the synchronized phase for event arrival if
+ * either callback was registered */
+ if (info.end == info.cur &&
+ ((data->cb_id2 < 0 && data->cb_id2 < 0) || --retries
== 0)) {
+ ret = VIR_DOMAIN_BLOCK_JOB_READY;
+ goto cleanup;
+ }
}
if (data->verbose)
--
2.4.3