Re: performance testing

[Valerie Clement <valerie.clement@bull.net>]

Valerie Clement wrote:
> Alex Tomas wrote:
>> Jean noel Cordenner wrote:
>>> The last patch queue concerns the  2.6.22-rc4 kernel, so we took the
>>> previous ext4 patch queue including the modifications suggested by 
>>> dmitriy:
>>> http://article.gmane.org/gmane.comp.file-systems.ext4/2291
>>> This solve the oops problem but after a while, the system hangs. We are
>>> still trying to find where the bug is.
>>> When we remove all the patches until booked-page-flag.patch in the
>>> series, the system still hangs. When using another filesystem, or
>>> whithout any patches it works.
>>
>> any details? backtraces? dmesg?
> 
> We are trying to get some traces, but with 2.6.22-rc5 and 2.6.22-rc6 
> kernels, the serial console isn't working on our systems (x86_64), the 
> magic SysRq keys either. Strange...
> 
> When the system hangs, no messages are logged.
> It seems that the hangs only occur with ext4 FS when applying the 
> patches of the current git tree.
> We are trying now to find which patch is faulty.
> 
>    Valérie
> 

It seems that the faulty patch is "ext4-journal_chksum-2.6.20.patch".
Looking at the patch, I think the following change is not correct:

@@ -116,21 +120,36 @@ static int journal_write_commit_record(j

     bh = jh2bh(descriptor);

-   /* AKPM: buglet - add `i' to tmp! */
     for (i = 0; i < bh->b_size; i += 512) {
-       journal_header_t *tmp = (journal_header_t*)bh->b_data;
+       struct commit_header *tmp = (struct commit_header*)bh->b_data +
+                                           i;

Shouldn't it be :

   struct commit_header *tmp = (struct commit_header*)(bh->b_data + i);

Valérie