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Newsgroups: mail-lists.delegate-en

[DeleGate-En] Re: Delegate with NFS cache spool
11 Mar 2009 12:32:35 GMT (Yutaka Sato)
The DeleGate Project

Hi Eddie,

Thank you for the detailed information.  It seems that the problem is caused
because feof() does not become true on ESTALE in getc(), so fgetsZ() does
not return NULL, then it is retried endlessly.  I could reproduce it on my
machines (so far on Solaris10 and FedoraCore6) and it was fixed as the
enclosed patch to fgetsZ(). 

In message <_A4405@delegate-en.ML_> on 03/11/09(17:02:30)
you Eddie Stassen <> wrote:
 |> In message <_A4372@delegate-en.ML_> on 02/20/09(23:17:57)
 |> you Eddie Stassen <> wrote:
 |>  |We are running delegate as a caching proxy NNTP server (on Solaris 10) 
 |>  |using NFS mounted drives as a cache spool.  Now and then we find 'stuck' 
 |>  |delegated processes which take up a lot of CPU cycles.  Running truss, 
 |>  |it appears that the process is getting an ESTALE error when reading from 
 |>  |the spool (not sure why this is, possibly a file deleted while it was 
 |>  |being read), however it seems  delegated is ignoring the error and 
 |>  |sitting in a tight loop continuously retrying to read.  I have had a 
 |>  |look through the source code to try and figure out where this is 
 |>  |happening, but without much success so far.
 |>  |
 |>  |Could you perhaps have a look and see if a fix could be made, or perhaps 
 |>  |point me to the correct place in the code so I can make a temporary hack?
 |> The first step should be locating where it occurs.  The output of
 |> truss might imply where it is.  Or you can inspect the process
 |> with mdb for example as "mdb -p ProcessId" and dump the calling
 |> stack with the "$c" command.
 |I have managed to get the following information which might help to 
 |pinpoint the problem.
 |$ pstack 26448
 |26448:  /opt/local/news/delegate-test/sbin/delegated +=/opt/local/news/delegat
 | ff04a748 _read    (41daa8, 3a31f0, a9, 0, 43c124, ffbb7fb8) + c
 | 0024be60 _Z6fgetsZPKciS0_iS0_iP6__FILE (32b730, 193, ffbb7bb8, 400, ffbb7bb8, ffbb7fb6) + 21c
 | 0028f304 _Z8fgetsTeePKciS0_iS0_iP6__FILES2_S2_i (32b730, 402, ffbb7bb8, 400, ffbb7bb8, 400) + 134

  9 9   Yutaka Sato <>
 ( ~ )  National Institute of Advanced Industrial Science and Technology
_<   >_ 1-1-4 Umezono, Tsukuba, Ibaraki, 305-8568 Japan
Do the more with the less -- B. Fuller

*** dist/src/delegate9.9.2-pre7/rary/String.c	Mon Mar  2 14:04:36 2009
--- ./rary/String.c	Wed Mar 11 21:18:52 2009
*** 2583,2588 ****
--- 2583,2591 ----
  	if( sp == str && feof(fp) )
  		return NULL;
+ 	if( sp == str && ch == EOF ){
+ 		return NULL;
+ 	}
  	return str;
  int fputsZ(PCStr(str),FILE *fp){

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