Re: [libvirt] [PATCH] Fix up connection reference counting.

Currently the reference counting for connections is busted. I first noticed it while trying to use virConnectRef; it would eventually cause a crash in the remote_internal driver, although that was really just a victim. Really, we should only call the close callbacks on the methods when the references drop to 0. To accomplish this, move all of the close callbacks into virUnrefConnect (since there are lots of internal users of that function), and arrange for virConnectClose to call that. V2: Make sure to drop the connection lock before we call the close callbacks, otherwise we could deadlock the daemon Signed-off-by: Chris Lalancette <clalance(a)redhat.com&gt; --- src/datatypes.c | 19 +++++++++++++++++++ src/libvirt.c | 14 +------------- 2 files changed, 20 insertions(+), 13 deletions(-) diff --git a/src/datatypes.c b/src/datatypes.c index 9d556c8..bcb5fd4 100644 --- a/src/datatypes.c +++ b/src/datatypes.c @@ -237,6 +237,25 @@ virUnrefConnect(virConnectPtr conn) conn->refs--; refs = conn->refs; if (refs == 0) { + /* make sure to release the connection lock before we call the + * close() callbacks, otherwise we will deadlock if an error + * is raised by any of the callbacks + */ + virMutexUnlock(&conn->lock); + if (conn->networkDriver) + conn->networkDriver->close (conn); + if (conn->interfaceDriver) + conn->interfaceDriver->close (conn); + if (conn->storageDriver) + conn->storageDriver->close (conn); + if (conn->deviceMonitor) + conn->deviceMonitor->close (conn); + conn->driver->close (conn); + + /* reacquire the connection lock since virReleaseConnect expects + * it to already be held + */ + virMutexLock(&conn->lock); virReleaseConnect(conn); /* Already unlocked mutex */ return (0); diff --git a/src/libvirt.c b/src/libvirt.c index 5aa7f83..472c19b 100644 --- a/src/libvirt.c +++ b/src/libvirt.c @@ -1231,19 +1231,7 @@ virConnectClose(virConnectPtr conn) return (-1); } - if (conn->networkDriver) - conn->networkDriver->close (conn); - if (conn->interfaceDriver) - conn->interfaceDriver->close (conn); - if (conn->storageDriver) - conn->storageDriver->close (conn); - if (conn->deviceMonitor) - conn->deviceMonitor->close (conn); - conn->driver->close (conn); - - if (virUnrefConnect(conn) < 0) - return (-1); - return (0); + return virUnrefConnect(conn); } /**