[9fans] p9p acme freezes when ctrl-f inside its mounted directory

[9fans] p9p acme freezes when ctrl-f inside its mounted directory

[Rudolf Sykora]

Hello,

I noticed that when running acme in plan9port and having its
directories mounted say on /mnt/acme, then if I try from within a win
window in the acme to auto-complete a directory name---I am in /mnt, I
type 'a' and hit the 'insert' key or ctrl-f, or I am anywhere inside
the acme filesystem---the program freezes (though, if I write it
myself, I can cd to the acme directory).

Am I doing sth wrong or it shouldn't do so?

Thanks
Ruda

Re: [9fans] p9p acme freezes when ctrl-f inside its mounted directory

[Russ Cox]

On Tue, Aug 4, 2009 at 10:33 AM, Rudolf Sykora<rudolf.sykora@gmail.com> wrote:
> I noticed that when running acme in plan9port and having its
> directories mounted say on /mnt/acme, then if I try from within a win
> window in the acme to auto-complete a directory name---I am in /mnt, I
> type 'a' and hit the 'insert' key or ctrl-f, or I am anywhere inside
> the acme filesystem---the program freezes (though, if I write it
> myself, I can cd to the acme directory).

The problem is that acme is basically a single
operating system thread, and that operating system
thread is trying to look in /mnt/acme.  To serve that
request, the kernel has posted a FUSE message to
acme to handle, which acme will get around to just as
soon as the system call in /mnt/acme finishes.
Deadlock.

This is not a problem on Plan 9 because acme does
not put itself in its own name space.  On Linux, where
there is just one big name space, more care is necessary
(and not implemented).

Russ

Re: [9fans] p9p acme freezes when ctrl-f inside its mounted directory

[Rudolf Sykora]

2009/8/5 Russ Cox <rsc@swtch.com>:
> On Tue, Aug 4, 2009 at 10:33 AM, Rudolf Sykora<rudolf.sykora@gmail.com> wrote:
>> I noticed that when running acme in plan9port and having its
>> directories mounted say on /mnt/acme, then if I try from within a win
>> window in the acme to auto-complete a directory name---I am in /mnt, I
>> type 'a' and hit the 'insert' key or ctrl-f, or I am anywhere inside
>> the acme filesystem---the program freezes (though, if I write it
>> myself, I can cd to the acme directory).
>
> The problem is that acme is basically a single
> operating system thread, and that operating system
> thread is trying to look in /mnt/acme.  To serve that
> request, the kernel has posted a FUSE message to
> acme to handle, which acme will get around to just as
> soon as the system call in /mnt/acme finishes.
> Deadlock.
>
> This is not a problem on Plan 9 because acme does
> not put itself in its own name space.  On Linux, where
> there is just one big name space, more care is necessary
> (and not implemented).
>
> Russ
>
>

Thanks for the explanation!
R