openssh unix dev - Dec 2007 - [sshfs] sshfs mounted applications fail with "error loading shared libraries"

> On Dec 3, 2007 5:19 AM, Miklos Szeredi <miklos at szeredi.hu> wrote:
> > > Yes it is weird. I hope you can help me with this problem as
sshfs is
> > > so much simpler than nfs.
> >
> > Can you please do one more thing: start up sshfs normally, then on the
> > server do a strace of the sftp-server process:
> >
> >  strace -o /tmp/strace.log -p `pidof sftp-server`
> 
> Attached the sftp-server log.
Thanks.  I think I can see the explanation.  Here's the failure:

   read(3, "\0\0\0H\3\0\0\3\347\0\0\0003/mnt/exports/tools/"...,
16384) = 140
   open("/mnt/exports/tools/ISE9.2i/bin/lin64/libXst_Core.so",
O_RDONLY) = 105
   close(105)                              = 0
   select(5, [3], [4], NULL, NULL)         = 1 (out [4])
   write(4, "\0\0\0\30e\0\0\3\347\0\0\0\4\0\0\0\7Failure\0\0\0\0", 28)
= 28

The file handle is 105, which suggests, that there's some limit around
100 open files.  Looking at the sftp-server source confirms this:

   Handle  handles[100];

So, unfortunately it seems sftp-server can only handle 100 open files
at a time.

It's easy enough to fix, if you are willing to recompile the
sftp-server binary.

Miklos

On Dec 4, 2007 2:03 AM, Miklos Szeredi <miklos at szeredi.hu>
wrote:
>
> > On Dec 3, 2007 5:19 AM, Miklos Szeredi <miklos at szeredi.hu>
wrote:
> > > > Yes it is weird. I hope you can help me with this problem as
sshfs is
> > > > so much simpler than nfs.
> > >
> > > Can you please do one more thing: start up sshfs normally, then
on the
> > > server do a strace of the sftp-server process:
> > >
> > >  strace -o /tmp/strace.log -p `pidof sftp-server`
> >
> > Attached the sftp-server log.
>
> Thanks.  I think I can see the explanation.  Here's the failure:
>
>    read(3, "\0\0\0H\3\0\0\3\347\0\0\0003/mnt/exports/tools/"...,
16384) = 140
>    open("/mnt/exports/tools/ISE9.2i/bin/lin64/libXst_Core.so",
O_RDONLY) = 105
>    close(105)                              = 0
>    select(5, [3], [4], NULL, NULL)         = 1 (out [4])
>    write(4,
"\0\0\0\30e\0\0\3\347\0\0\0\4\0\0\0\7Failure\0\0\0\0", 28) = 28
>
> The file handle is 105, which suggests, that there's some limit around
> 100 open files.  Looking at the sftp-server source confirms this:
>
>    Handle  handles[100];
>
> So, unfortunately it seems sftp-server can only handle 100 open files
> at a time.
>
> It's easy enough to fix, if you are willing to recompile the
> sftp-server binary.
>
Thanks Miklos. I guess arbitrarily increasing the number of handles is
not a good long term fix. It is hard to guesstimate how many clients
can be supported through a single sshfs mounted file system if there
is a fundamental file handle limit in sftp-server. Making it 1000 is
going to fail somewhere else down the line. Is that correct?

p.s,

I am recompiling sftp-server with 1000 handles to verify that at-least
I can get one client working.