<font color="#3333ff"><font size="2"><font face="times new roman,serif">Hi Alexey,<br>
<br>
Thanks again for your reply.<br>
<br>
I am trying to embed a buffer in the RPC which will get filled in with some values which MDS is aware of which the client calling the RPC is not aware of.It has nothing to do with locking.I just want to fill in the buffer which I embedd in the RPC with some suitable data from the MDS end and then do operations on that data at the client side.So I think the approach suggested by you and Nicholas of just including the sizeof(str) [the size of the expected information from the MDS] in the size[] array should be fine as done below :-<br>
<br><br><br></font></font></font><font face="'times new roman', serif"><font color="#3333ff">__u32 size[2] = { [MSG_PTLRPC_BODY_OFF] = sizeof(struct ptlrpc_body),</font></font>
<div><font face="'times new roman', serif"><font color="#3333ff"> [DLM_LOCKREQ_OFF] = sizeof(struct ldlm_request) };</font></font></div>
<div><font face="'times new roman', serif"><font color="#3333ff"><br></font></font></div><div><font face="'times new roman', serif"><font color="#3333ff">---->> </font></font></div>
<div><font face="'times new roman', serif"><font color="#3333ff"> __u32 size[3] = { [MSG_PTLRPC_BODY_OFF] = sizeof(struct ptlrpc_body),</font></font></div><div>
<font face="'times new roman', serif"><font color="#3333ff"> [DLM_LOCKREQ_OFF] = sizeof(struct ldlm_request) ,</font></font></div>
<div><font face="'times new roman', serif"><font color="#3333ff">
//how to add "char *str=Hello" ofcourse we
will have sizeof(str) but how to choose the MACRO like </font></font><span style="font-family: 'times new roman',serif; color: rgb(51, 51, 255);">DLM_LOCKREQ_OFF bcz for a specific kind of RPC there are limited number of such MACROS</span></div>
<font color="#3333ff"><font size="2"><font face="times new roman,serif"> <br><br><b>Please correct me if I am wrong or please guide me if I need to consider few corner cases to handle this use case.<br><br></b>Thanks again.<br>
<br clear="all"></font></font></font><font style="color: rgb(51, 51, 255);" size="2" color="#3333ff"><font face="'times new roman', serif">Thanks,<br>Vilobh<br>
</font></font><i><font style="color: rgb(51, 51, 255);" size="2">Graduate Research Associate<br>Department of Computer Science<br>The Ohio State University Columbus Ohio</font></i><br>
<br clear="all"><font style="color: rgb(51, 51, 255);" size="2" color="#3333ff"><font face="'times new roman', serif"></font></font><br><div class="gmail_quote">On Thu, Oct 14, 2010 at 10:40 AM, Alexey Lyashkov <span dir="ltr"><<a href="mailto:alexey.lyashkov@clusterstor.com">alexey.lyashkov@clusterstor.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Andreas,<br>
<div class="im"><br>
On Oct 14, 2010, at 17:31, Andreas Dilger wrote:<br>
<br>
> On 2010-10-13, at 23:18, Nicolas Williams wrote:<br>
>> On Thu, Oct 14, 2010 at 06:38:16AM +0300, Alexey Lyashkov wrote:<br>
>>> On Oct 14, 2010, at 03:28, Nicolas Williams wrote:<br>
>>>> Yes, it's possible to add buffers to requests. It's not possible to add<br>
>>>> buffers to _replies_ to existing RPCs unless you know the client expects<br>
>>>> those additional buffers -- existing clients expect a given maxsize for<br>
>>>> each reply, and if your reply is bigger then it will get dropped.<br>
>>> It is wrong for last ~1year.<br>
>>> ~1year ago i add code to ptlrpc layer which a adjust buffer for reply, and resend a request.<br>
>><br>
>> Ah, I didn't know that was in 1.8. Are there interop issues (with older<br>
>> clients) though with sending larger replies than expected?<br>
><br>
> Nico, it has always been possible in the past to increase the size of any buffer in a request, or in a reply (if the total reply size will fit into the pre-allocated reply buffer). An older peer would just ignore the bytes beyond the known part of the buffer.<br>
><br>
</div>I think that question don't about rebalance buffers size in message,<br>
i think that sending large reply in smaller reply buffer.<br>
LNet don't able to put large reply to small buffer (without truncate flag, which is not exist in older ptlrpc version).<br>
without that flag you will see messages<br>
>><br>
CERROR("Matching packet from %s, match "LPU64<br>
" length %d too big: %d left, %d allowed\n",<br>
libcfs_id2str(src), match_bits, rlength,<br>
md->md_length - offset, mlength);<br>
>><br>
and LNet will drop message without notify PtlRPC.<br>
<div class="im"><br>
<br>
> Is that not true with the 2.x RPC handling?<br>
><br>
</div>2.x able to rebalance space between buffers (but looks by hand), and able adjust reply buffer after truncated reply.<br>
<div><div></div><div class="h5"><br>
<br>
<br>
--------------------------------------<br>
Alexey Lyashkov<br>
<a href="mailto:alexey.lyashkov@clusterstor.com">alexey.lyashkov@clusterstor.com</a><br>
<br>
<br>
<br>
<br>
</div></div></blockquote></div><br>