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. Regards, Yury
