Re: [libvirt] [PATCH v7 2/6] add fuse support for libvirt lxc
于 2012年11月06日 16:34, Richard W.M. Jones 写道:
On Tue, Nov 06, 2012 at 02:07:18PM +0800, Gao feng wrote:
> +static int
> +virLXCControllerSetupFuse(virLXCControllerPtr ctrl)
> +{
> + int try = 0;
> + virThread thread;
> + if (virThreadCreate(&thread, true, lxcRegisterFuse,
> + (void *)ctrl->def) < 0)
> + return -1;
> + /*
> + * because libvirt_lxc may use fuse filesystem before fuse being
> + * mounted by the thread. so wait 3 seconds in libvirt_lxc. if fuse
> + * is not mounted in 3 seconds, libvirt_lxc will exit.
> + */
> + while (try++ < 2) {
> + if (lxcRegisterFuseSuccess())
> + return 0;
> +
> + sleep(1);
> + }
> +
> + return -1;
> +}
This code seems like it is bound to cause trouble. Can you explain
why the arbitrary wait is required here?
Because libvirt_lxc create a thread to mount fuse filesystem.
and then libvirt_lxc will try to access the fuse filesystem.
Without waiting,libvirt_lxc may access fuse before it is mounted.
And I can't find a better way to make accessing fuse after the fuse
being mounted,because fuse_main will return until fuse being unmounted,so
I don't know how to pass message to tell libvirt_lxc whether the fuse is
mounted success.
> diff --git a/src/lxc/lxc_fuse.c b/src/lxc/lxc_fuse.c
> new file mode 100644
> index 0000000..42107d7
> --- /dev/null
> +++ b/src/lxc/lxc_fuse.c
> @@ -0,0 +1,157 @@
> +/*
> + * Copyright (C) 2012 Fujitsu Limited.
> + *
> + * lxc_fuse.c: fuse filesystem support for libvirt lxc
[...]
The basic empty directory fuse filesystem seems fine. I see
that patch 5/6 adds one(?) file to this directory, also fine.
Thanks for your review.
Gao