[libvirt] [PATCH 5/3] qemu: don't leave shutdown inhibited on attach failure

[Eric Blake]

While debugging a failure of 'virsh qemu-attach', I noticed that
we were leaking the count of active domains on failure.  This
means that a libvirtd session that is supposed to quit after
active domains disappear will hang around forever.

* src/qemu/qemu_process.c (qemuProcessAttach): Undo count of
active domains on failure.

Signed-off-by: Eric Blake <eblake at redhat.com>
---

Quite a few latent bugs being uncovered while still drilling
down to the root cause of attaching not working.

 src/qemu/qemu_process.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 128618b..6fb4a4f 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -4353,6 +4353,7 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED,
     const char *model;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
     virCapsPtr caps = NULL;
+    bool active = false;

     VIR_DEBUG("Beginning VM attach process");

@@ -4378,6 +4379,7 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED,

     if (virAtomicIntInc(&driver->nactive) == 1 && driver->inhibitCallback)
         driver->inhibitCallback(true, driver->inhibitOpaque);
+    active = true;

     if (virFileMakePath(cfg->logDir) < 0) {
         virReportSystemError(errno,
@@ -4549,9 +4551,12 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED,
     return 0;

 cleanup:
-    /* We jump here if we failed to start the VM for any reason, or
-     * if we failed to initialize the now running VM. kill it off and
-     * pretend we never started it */
+    /* We jump here if we failed to attach to the VM for any reason.
+     * Leave the domain running, but pretend we never attempted to
+     * attach to it.  */
+    if (active && virAtomicIntDecAndTest(&driver->nactive) &&
+        driver->inhibitCallback)
+        driver->inhibitCallback(false, driver->inhibitOpaque);
     VIR_FORCE_CLOSE(logfile);
     VIR_FREE(seclabel);
     VIR_FREE(sec_managers);
-- 
1.8.3.1