John Ferlan <jferlan@xxxxxxxxxx> [2016-07-21, 12:23PM +0200]:
On 07/08/2016 06:30 AM, Bjoern Walk wrote:Since return code is checked globally at the end of the function, let's make sure that we set it correctly at any point. This fixes a regression introduced in commit 0aa19f35 where the first command to eject changeable media would fail unconditionally. Signed-off-by: Bjoern Walk <bwalk@xxxxxxxxxxxxxxxxxx> Reviewed-by: Boris Fiuczynski <fiuczy@xxxxxxxxxxxxxxxxxx> --- src/qemu/qemu_hotplug.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index c322543..789f18c 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -240,7 +240,8 @@ qemuDomainChangeEjectableMedia(virQEMUDriverPtr driver, /* If the tray is present and tray change event is supported wait for it to open. */ if (diskPriv->tray && virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE_TRAY_MOVED)) { - if (qemuHotplugWaitForTrayEject(driver, vm, disk, driveAlias, force) < 0) + rc = qemuHotplugWaitForTrayEject(driver, vm, disk, driveAlias, force); + if (rc < 0) goto error;But rc isn't checked in the error and cleanup labels in qemuDomainChangeEjectableMedia, so not sure what the purpose of setting rc is. What am I missing?
It takes two issues of qemuMonitorEjectMedia in order to successfully
eject the media as far as I understood because the first only opens the
tray only. Hence
235 qemuDomainObjEnterMonitor(driver, vm);
236 rc = qemuMonitorEjectMedia(priv->mon, driveAlias, force);
rc == -1 for the first call.
237 if (qemuDomainObjExitMonitor(driver, vm) < 0)
238 goto cleanup;
239
240 /* If the tray is present and tray change event is supported wait for it to open. */
241 if (diskPriv->tray &&
242 virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE_TRAY_MOVED)) {
243 if (qemuHotplugWaitForTrayEject(driver, vm, disk, driveAlias, force) < 0)
This is the second call to qemuMonitorEjectMedia after waiting an
appropriate time to process the tray open command above. This call
succeeds and returns 0 but the return code rc is _not_ set, so rc is
still -1.
244 goto error;
245 } else {
246 /* otherwise report possible errors from the attempt to eject the media*/
247 if (rc < 0)
248 goto error;
249 }
250
251 if (!virStorageSourceIsEmpty(newsrc)) {
This doesn't get called for just an eject media command...
[...]
264 rc = qemuMonitorChangeMedia(priv->mon,
... but it _would_ actually set rc correctly.
265 driveAlias,
266 sourcestr,
267 format);
268 if (qemuDomainObjExitMonitor(driver, vm) < 0)
269 goto cleanup;
270 }
271
272 virDomainAuditDisk(vm, disk->src, newsrc, "update", rc >= 0);
273
274 if (rc < 0)
275 goto error;
Since rc is still -1 because it did not get set properly on each branch,
the function errors out despite actually succeeding. This is the actual
behaviour of this function prior to the refactoring, so I guess it's
just a simple oversight. Unfortunately, the test suite did not catch
this because of a missing mock in qemuhotplugtest.
The existing "else" in the code is for (diskPriv->tray && virQEMU...)
condition as I see it.
If perhaps you had just set rc, not done the goto, and remove the else
condition, e.g.:
if (diskPriv... && virQEMUCaps...)
rc = qemuHotplugWait...
if (rc < 0)
goto error;
that's just doing the same thing in a different way.
I don't understand. My patch restores the exact functional behaviour of this function prior to the refactor. I do see a spurious error message when issuing the first change-media --eject command. This is gone with my patch applied. If the function is otherwise misbehaving I can not tell.
John} else { /* otherwise report possible errors from the attempt to eject the media*/
Best,
Bjoern
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