于 2012年11月07日 16:50, Richard W.M. Jones 写道: > On Wed, Nov 07, 2012 at 01:45:27PM +0800, Wanlong Gao wrote: >> On 11/07/2012 11:54 AM, Gao feng wrote: >>> 于 2012年11月06日 20:55, Richard W.M. Jones 写道: >>>> On Tue, Nov 06, 2012 at 07:50:33PM +0800, Gao feng wrote: >>>>> 于 2012年11月06日 17:11, Richard W.M. Jones 写道: >>>>>> On Tue, Nov 06, 2012 at 04:54:59PM +0800, Gao feng wrote: >>>>>>> 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. >>>>>> >>>>>> Oh I see. This is solvable, but I believe that you cannot use >>>>>> fuse_main. You have to look at the fuse sources (quite complex!) and >>>>>> do the individual fuse operations. >>>>>> >>>>>> Have a look at how libguestfs does it ... >>>>>> >>>>>> https://github.com/libguestfs/libguestfs/blob/master/src/fuse.c#L911 >>>>>> http://libguestfs.org/guestfs.3.html#mount-local >>>>>> >>>>> >>>>> >>>>> Thanks for the information. >>>>> >>>>> Can fuse_mount & fuse_new & fuse_loop avoid the waiting? >>>>> >>>>> It seems has the same problem. >>>> >>>> It waits, but it doesn't busy wait in a loop. The first access to the >>>> filesystem hangs until the thread which is handling the filesystem is >>>> listening for requests. >>>> >>> >>> It makes me confuse. >>> >>> There are two threads(A and B). >>> thread A mounts fuse filesystem on mountpoint /mnt/fuse. >>> thread B try to access file /mnt/fuse/meminfo. and we don't >>> know which thread will execute first. >>> >>> The information I got from your comment is that because thread A >>> doesn't mount fuse to /mnt/fuse, when thread B access to the >>> /mnt/fuse/meminfo,it will hang. I am right? >> >> If I'm not wrong, I think Rich means that you should create the mountpoint >> and the operations using fuse_mount and fuse_new before you create the thread B, >> then make another thread A using fuse_loop to loop behind. Then if thread B try >> to access the mountpoint before thread A runs, B will hang until thread A runs into the loop. > > This is right. > With my test and reading fuse source,the thread B will return with error ENOTCONN. Thanks Gao -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list