[Lustre-devel] RE: Lustre echo question

Eric Barton
2006-08-29T07:15:21Z

Scott,

> Please let me know if you are still not back full time. If so, I can
> post this to the devel list.

yes; I''m back :)

> We are working on cleaning up MX on client reconnect (so MXLND can
> cancel outstanding txs and rxs). At the same time, we are merging our
> MX-2G and MX-10G code branches and we may have introduced a bug in MX
> that I am seeing in MXLND. I am using your ltest scripts and I have
> not seen these messages before:
>
> Aug 29 07:58:59 172.31.164.34 kernel: LustreError: 5642:0:(debug.c:
> 167:block_debug_check()) echo: id 0x3 offset 556720128 end off:
> 0x212de000 != 0x212ee000
> Aug 29 07:58:59 172.31.164.34 kernel: LustreError: 5642:0:(debug.c:
> 155:block_debug_check()) echo: id 0x3 offset 556724224 off:
> 0x212df000 != 0x212ef000
>
> I assume that LNET is checking the bulk read and writes to ensure the
> correct data was transfered. What is it checking specifically?

yes indeed.  Both client and server do checks on a few locations at the
start and end of each page of bulk data.  Look for block_debug_setup() and
block_debug_check(), and where obdecho and echo_client call them to
set/check the object number and file offset in each block (page) of bulk
I/O.  It looks like data for the previous block got into this one.

                Cheers,
                        Eric

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