Re: [PATCH] migration/multifd: Don't fsync when closing QIOChannelFile

[Peter Xu <peterx@redhat.com>]

On Tue, Mar 05, 2024 at 05:49:33PM +0000, Daniel P. Berrangé wrote:
> I don't think you should be removing this. Calling qio_channel_close()
> remains recommended best practice, even with fdatasync() removed, as
> it provides a strong guarantee that the FD is released which you don't
> get if you rely on the ref count being correctly decremented in all
> code paths.

Hmm, I have the confusion on why ioc->fd is more special than the ioc
itself when leaked.  It'll be a bug anyway if we leak any of them?  Leaking
fds may also help us to find such issue easier (e.g. by seeing stale fds
under /proc).  From that POV I tend to agree on the original proposal.

Now we removed the data sync, IIUC it means the mgmt can always flush the
cache with/without the fd closed in QEMU even if it's leaked.  So I don't
yet see other side effects of leaking the fd which will cause a difference
comparing to leaking the ioc?

Thanks,

-- 
Peter Xu