Hangs !!! Accessing fuse filesystem in Windows through Samba

[Jeremy Allison]

On Mon, Mar 02, 2015 at 08:00:47AM -0800, Richard Sharpe wrote:
> On Mon, Mar 2, 2015 at 7:34 AM, Raj Kumar Sanpui
> <raj.kumar.sanpui at gmail.com> wrote:
> > We are accessing a fuse filesystem in Windows through Samba.
> >
> > There are 2 category of files in fuse filesystem, local and remote (Data
> > Center). If the file is in remote, fuse downloads it internally when open(
> > ) syscall is invoked by the filesystem - at which stage open( ) waits or
> > blocks till the complete file is downloaded - At this stage we see, the
> > Samba share becomes unresponsive and hangs.
> >
> > However, if some other user tries the same fuse mount from a Samba share in
> > different machine it works.
> >
> > Why does this happen, is it due to the single threaded nature of Samba? Is
> > there any workaround for this?
> 
> Samba used event processing (tevent) not threads.
> 
> It is hard for open to be async, and Samba expects open to not take a
> lot of time.

On Linux, where we have per-thread creds, you can get
open async by using aio_pthread and setting the aio_pthread
specific parameter "aio open = true".