[9fans] venti p9p problems

[9fans] venti p9p problems

[Matthias Bauer, Matthias Bauer]

Hi 9fans,

While playing with p9p venti and vac I came about 
the following problem:

The venti server is running on OpenBSD 4.0.
I stored a directory (about 115Mb) in venti with vac. The debugging
output told that it stored all the files on the
server. After transferring the vacfile to a plan9 host,
I tried to access the stored directory with vacfs vacfile.

Unfortunately the /n/vac/ dir only contains the dot .

C-Keen and I retried several times on different machines, slightly
different venti setups (arenas, isects) and with
lots of debugging options, but could not get at
the data.

Below is the log of the last vacfs try (for vac:7c59cdd58e2ea5d654c74f1eea25caea91071c31)
as returned by the venti-http.

Thanks,

Matthias 

------
work ventiserver: start request Tread tag 0 score 7c59cdd58e2ea5d654c74f1eea25caea91071c31 blocktype 16 count 300
rpc ventiserver: <- Tread tag 0 score 7c59cdd58e2ea5d654c74f1eea25caea91071c31 blocktype 16 count 300
lump ventiserver: readlump enter
lump ventiserver: lookuplump enter
lump ventiserver: lookuplump hit
lump ventiserver: lookuplump exit
lump ventiserver: readlump lookuplump hit
lump ventiserver: putlump
lump ventiserver: putlump wakeup
rpc ventiserver: -> Rread tag 0 count 300
work ventiserver: start
work ventiserver: finish
work ventiserver: start request Tread tag 0 score 1566fc8077e44a034f804b302a57968b79a6040f blocktype 8 count 8192
rpc ventiserver: <- Tread tag 0 score 1566fc8077e44a034f804b302a57968b79a6040f blocktype 8 count 8192
lump ventiserver: readlump enter
lump ventiserver: lookuplump enter
lump ventiserver: lookuplump hit
lump ventiserver: lookuplump exit
lump ventiserver: readlump lookuplump hit
lump ventiserver: putlump
lump ventiserver: putlump wakeup                                                                                           
rpc ventiserver: -> Rread tag 0 count 120
work ventiserver: start                                                                                                    
work ventiserver: finish
work ventiserver: start request Tread tag 0 score 73999d40ad65f71b598eb5d1f6c7793f6a56e11d blocktype 0 count 8192
rpc ventiserver: <- Tread tag 0 score 73999d40ad65f71b598eb5d1f6c7793f6a56e11d blocktype 0 count 8192
lump ventiserver: readlump enter
lump ventiserver: lookuplump enter
lump ventiserver: lookuplump hit
lump ventiserver: lookuplump exit
lump ventiserver: readlump lookuplump hit
lump ventiserver: putlump
lump ventiserver: putlump wakeup
rpc ventiserver: -> Rread tag 0 count 412
work ventiserver: start                                                                                                    
proc delaykickproc dcache: kickround 0xc
proc delaykickproc dcache: kick dcache                                                                                     
work flushproc: start
proc flushproc: build t=1
proc flushproc: writeblocks t=31
proc flushproc: writeblocks.1 t=55
proc flushproc: writeblocks.2 t=79
proc flushproc: writeblocks.3 t=103
proc flushproc: undirty.4 t=127
work flushproc: finish
proc delaykickproc dcache: finishround 0xc
proc delaykickproc dcache: waitround 0xd
work ventiserver: finish
work ventiserver: start request Tread tag 0 score e1f18bbaa8e1378bd816f008648d579a7aeac895 blocktype 0 count 8192
rpc ventiserver: <- Tread tag 0 score e1f18bbaa8e1378bd816f008648d579a7aeac895 blocktype 0 count 8192
lump ventiserver: readlump enter
lump ventiserver: lookuplump enter
lump ventiserver: lookuplump hit
lump ventiserver: lookuplump exit
lump ventiserver: readlump lookuplump hit
lump ventiserver: putlump
lump ventiserver: putlump wakeup
rpc ventiserver: -> Rread tag 0 count 406
work ventiserver: start

Re: [9fans] venti p9p problems

[Russ Cox]

The problem is that your vac archive has a
single top-level directory named ".".  Good luck
cd'ing into that directory.  ;-)

Did you run "vac ." ?  I though vac had been fixed
not to record that as a top-level name, but maybe
it was only / that got fixed.

In src/cmd/vac/vacfs.c you will find the workaround
from when vac used to save archives with a top-level
directory named "/":

VacFile*
_vfWalk(VacFile *file, char *name)
{
	VacFile *n;

	n = vacfilewalk(file, name);
	if(n)
		return n;
	if(strcmp(name, "SLASH") == 0)
		return vacfilewalk(file, "/");
	return nil;
}

Try adding near the end:

	if(strcmp(name, "DOT") == 0)
		return vacfilewalk(file, ".");

And then you should be able to access your archive.

Russ

Re: [9fans] venti p9p problems

[Matthias Bauer]

On Sun, Oct 01, 2006 at 09:41:35AM -0400, Russ Cox wrote:
> The problem is that your vac archive has a
> single top-level directory named ".".  Good luck
> cd'ing into that directory.  ;-)

Whaaaa. Right! I did use 'vac .'
Thanks for the hint in the right direction.
This OS _is_ fun :)

Matthias