On Mon, Apr 15, 2019 at 01:33:21PM +0300, Yury Kotov wrote: > 15.04.2019, 13:25, "Daniel P. Berrangé" <berra...@redhat.com>: > > On Mon, Apr 15, 2019 at 01:17:06PM +0300, Yury Kotov wrote: > >> 15.04.2019, 13:11, "Daniel P. Berrangé" <berra...@redhat.com>: > >> > On Mon, Apr 15, 2019 at 12:50:08PM +0300, Yury Kotov wrote: > >> >> Hi, > >> >> > >> >> Just to clarify. I see two possible solutions: > >> >> > >> >> 1) Since the migration code doesn't receive fd, it isn't responsible > >> for > >> >> closing it. So, it may be better to use migrate_fd_param for both > >> >> incoming/outgoing and add dupping for migrate_fd_param. Thus, clients > >> must > >> >> close the fd themselves. But existing clients will have a leak. > >> > > >> > We can't break existing clients in this way as they are correctly > >> > using the monitor with its current semantics. > >> > > >> >> 2) If we don't duplicate fd, then at least we should remove fd from > >> >> the corresponding list. Therefore, the solution is to fix qemu_close > >> to find > >> >> the list and remove fd from it. But qemu_close is currently > >> consistent with > >> >> qemu_open (which opens/dups fd), so adding additional logic might not > >> be > >> >> a very good idea. > >> > > >> > qemu_close is not appropriate place to deal with something speciifc > >> > to the montor. > >> > > >> >> I don't see any other solution, but I might miss something. > >> >> What do you think? > >> > > >> > All callers of monitor_get_fd() will close() the FD they get back. > >> > Thus monitor_get_fd() should remove it from the list when it returns > >> > it, and we should add API docs to monitor_get_fd() to explain this. > >> > > >> Ok, it sounds reasonable. But monitor_get_fd is only about outgoing > >> migration. > >> But what about the incoming migration? It doesn't use monitor_get_fd but > >> just > >> converts input string to int and use it as fd. > > > > The incoming migration expects the FD to be passed into QEMU by the mgmt > > app when it is exec'ing the QEMU binary. It doesn't interact with the > > monitor at all AFAIR. > > > > Oh, sorry. This use case is not obvious. We used add-fd to pass fd for > migrate-incoming and such way has described problems.
That's a bug in your usage of QEMU IMHO, as the incoming code is not designed to use add-fd. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
