Re: [Xen-devel] [PATCH] docs: remove wrong statement about bug in xenstore

[Juergen Gross <jgross@xxxxxxxx>]

On 24/10/16 13:41, Wei Liu wrote:
> On Mon, Oct 24, 2016 at 01:27:17PM +0200, Juergen Gross wrote:
>> docs/misc/xenstore.txt states that xenstored will use "0" as a valid
>> transaction id after 2^32 transactions. This is not true. Remove that
>> statement.
>>
>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> 
> Can you point me to the relevant code snippet? Better still I would like
> to see why it is the case in commit message.

Sure: tools/xenstore/xenstored_transaction.c

do_transaction_start():
...
        /* Pick an unused transaction identifier. */
        do {
                trans->id = conn->next_transaction_id;
                exists = transaction_lookup(conn,
conn->next_transaction_id++);
        } while (!IS_ERR(exists));

It should be noted here that conn->next_transaction_id is initialized
to be 0. So the error would occur for the first transaction, too.


Juergen

> 
>> ---
>>  docs/misc/xenstore.txt | 2 --
>>  1 file changed, 2 deletions(-)
>>
>> diff --git a/docs/misc/xenstore.txt b/docs/misc/xenstore.txt
>> index c9f4a05..ae1b6a8 100644
>> --- a/docs/misc/xenstore.txt
>> +++ b/docs/misc/xenstore.txt
>> @@ -229,8 +229,6 @@ TRANSACTION_START        |                       
>> <transid>|
>>      tx_id request header field.  When transaction is started whole
>>      db is copied; reads and writes happen on the copy.
>>      It is not legal to send non-0 tx_id in TRANSACTION_START.
>> -    Currently xenstored has the bug that after 2^32 transactions
>> -    it will allocate the transid 0 for an actual transaction.
>>  
>>  TRANSACTION_END             T|
>>  TRANSACTION_END             F|
>> -- 
>> 2.6.6
>>
> 


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