Bug report (12=17020 TC029) SAMBA 2.2.8 release 20040908 - intermittent content loss

John E. Malmberg wb8tyw at qsl.net
Fri Sep 24 14:22:09 GMT 2004


BG - Ben Armstrong wrote:
> On Fri, 2004-09-24 at 10:40 -0300, BG - Ben Armstrong wrote:
> 
>>>I am still trying to get familiar with this code, but I am finding 
>>>references to special handling if SAMBA detects that it is a VMS text file.
>>>
>>>Any VMS file that is not a stream or a fixed record size file may get 
>>>corrupted by an out-of-order transfer through SAMBA as the seek() 
>>>function will not go to the correct place on a write.
>>
>>OK, so far this is consistent with our test results.  We'll let you know
>>if we discover corruption in other file types, e.g. Stream or Stream-LF
>>files.
> 
> Oops, I misread that as "seek() ... on a read", but you said "on a
> write".  Since we're seeing the corruption before any output is written,
> your observations are *not* consistent with our test results.  So it
> remains a puzzle.

The reason that I said on a write() is that I have only observed the 
segmented out of order transfer on a write.

On a read, I would look for other causes.   It still could be a seek() 
issue.  It also could be that because SAMBA VMS estimated the size of 
the transfered data wrong, and the client believed it.

My guess is that if you do not use VFC file types the problem will go away.

I would recommend putting in a VMS specific bug report in Bugzilla for 
tracking purposes.  I am planning on using that to prioritize any 
changes that I do once I get the build environments for SAMBA2/3/4 under 
control.

At this time, I am looking at moving the file management into one or 
more VFS modules to make them simpler to maintain and debug.  And then I 
will also need test programs to verify their operation.

My suspicion is that once the corruption is properly characterized, I 
could probably be able to reproduce it with a small stub program that 
calls the VMS specific code in SAMBA, which would make it easier to debug.

-John
wb8tyw at qsl.net
Personal Opinion Only



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