* Smack on the head: Questions about pnfs write path
@ 2011-05-21 23:45 Boaz Harrosh
2011-05-22 0:16 ` Boaz Harrosh
0 siblings, 1 reply; 5+ messages in thread
From: Boaz Harrosh @ 2011-05-21 23:45 UTC (permalink / raw)
To: Benny Halevy, Fred Isaman, Trond Myklebust, NFS list
Fred git blame points to you:
What was the meaning of the below code:
@@ -1014,18 +1015,22 @@ static int nfs_flush_one(struct nfs_pageio_descriptor *desc)
*pages++ = req->wb_page;
}
req = nfs_list_entry(data->pages.next);
if ((!lseg) && list_is_singular(&data->pages))
lseg = pnfs_update_layout(desc->pg_inode, req->wb_context,
req_offset(req), desc->pg_count,
IOMODE_RW);
I mean why only the list_is_singular() case gets a pnfs_update_layout?
Because I have a very funny BUG:
If I do:
dd if=/dev/zero of=/mnt/pnfs/dd1 bs=4k count=1
I get a nice pnfs write out.
But if I do:
dd if=/dev/zero of=/mnt/pnfs/dd1 bs=4k count=2 (or any > 1)
I see all IO going to MDS
Below patch fixes that:
@@ -1014,18 +1015,22 @@ static int nfs_flush_one(struct nfs_pageio_descriptor *desc)
*pages++ = req->wb_page;
}
req = nfs_list_entry(data->pages.next);
- if ((!lseg) && list_is_singular(&data->pages))
+ if ((!lseg) /*&& list_is_singular(&data->pages)*/)
lseg = pnfs_update_layout(desc->pg_inode, req->wb_context,
req_offset(req), desc->pg_count,
IOMODE_RW);
Which points to what I'm saying all along. pNFS Write path had no testing
but by me.
(BTW am still fighting the unbalanced lseg ref)
Thanks
Boaz
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Smack on the head: Questions about pnfs write path
2011-05-21 23:45 Smack on the head: Questions about pnfs write path Boaz Harrosh
@ 2011-05-22 0:16 ` Boaz Harrosh
2011-05-23 14:22 ` Fred Isaman
0 siblings, 1 reply; 5+ messages in thread
From: Boaz Harrosh @ 2011-05-22 0:16 UTC (permalink / raw)
To: Benny Halevy, Fred Isaman, Trond Myklebust, NFS list
On 05/22/2011 02:45 AM, Boaz Harrosh wrote:
>
> Fred git blame points to you:
>
> What was the meaning of the below code:
>
OK Smack *ME* on the head
A layout driver must have a .pg_test function else
that's what happens. pNFS only for a single page.
I'd say it should be opposite no?
Boaz
> @@ -1014,18 +1015,22 @@ static int nfs_flush_one(struct nfs_pageio_descriptor *desc)
> *pages++ = req->wb_page;
> }
> req = nfs_list_entry(data->pages.next);
> if ((!lseg) && list_is_singular(&data->pages))
> lseg = pnfs_update_layout(desc->pg_inode, req->wb_context,
> req_offset(req), desc->pg_count,
> IOMODE_RW);
>
> I mean why only the list_is_singular() case gets a pnfs_update_layout?
>
> Because I have a very funny BUG:
> If I do:
> dd if=/dev/zero of=/mnt/pnfs/dd1 bs=4k count=1
> I get a nice pnfs write out.
> But if I do:
> dd if=/dev/zero of=/mnt/pnfs/dd1 bs=4k count=2 (or any > 1)
> I see all IO going to MDS
>
> Below patch fixes that:
> @@ -1014,18 +1015,22 @@ static int nfs_flush_one(struct nfs_pageio_descriptor *desc)
> *pages++ = req->wb_page;
> }
> req = nfs_list_entry(data->pages.next);
> - if ((!lseg) && list_is_singular(&data->pages))
> + if ((!lseg) /*&& list_is_singular(&data->pages)*/)
> lseg = pnfs_update_layout(desc->pg_inode, req->wb_context,
> req_offset(req), desc->pg_count,
> IOMODE_RW);
>
> Which points to what I'm saying all along. pNFS Write path had no testing
> but by me.
>
> (BTW am still fighting the unbalanced lseg ref)
>
> Thanks
> Boaz
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Smack on the head: Questions about pnfs write path
2011-05-22 0:16 ` Boaz Harrosh
@ 2011-05-23 14:22 ` Fred Isaman
2011-05-23 17:50 ` Benny Halevy
0 siblings, 1 reply; 5+ messages in thread
From: Fred Isaman @ 2011-05-23 14:22 UTC (permalink / raw)
To: Boaz Harrosh; +Cc: Benny Halevy, Trond Myklebust, NFS list
On Sat, May 21, 2011 at 8:16 PM, Boaz Harrosh <bharrosh@panasas.com> wrote:
> On 05/22/2011 02:45 AM, Boaz Harrosh wrote:
>>
>> Fred git blame points to you:
>>
>> What was the meaning of the below code:
>>
>
> OK Smack *ME* on the head
>
> A layout driver must have a .pg_test function else
> that's what happens. pNFS only for a single page.
> I'd say it should be opposite no?
>
Right now, a driver with no pg_test function erroneously misses the
pnfs_update_layout call in multi-page io. I'll send a patch to fix
that shortly.
Fred
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Smack on the head: Questions about pnfs write path
2011-05-23 14:22 ` Fred Isaman
@ 2011-05-23 17:50 ` Benny Halevy
2011-05-23 17:52 ` Benny Halevy
0 siblings, 1 reply; 5+ messages in thread
From: Benny Halevy @ 2011-05-23 17:50 UTC (permalink / raw)
To: Fred Isaman; +Cc: Boaz Harrosh, Trond Myklebust, NFS list
On 2011-05-23 17:22, Fred Isaman wrote:
> On Sat, May 21, 2011 at 8:16 PM, Boaz Harrosh <bharrosh@panasas.com> wrote:
>> On 05/22/2011 02:45 AM, Boaz Harrosh wrote:
>>>
>>> Fred git blame points to you:
>>>
>>> What was the meaning of the below code:
>>>
>>
>> OK Smack *ME* on the head
>>
>> A layout driver must have a .pg_test function else
>> that's what happens. pNFS only for a single page.
>> I'd say it should be opposite no?
>>
>
> Right now, a driver with no pg_test function erroneously misses the
> pnfs_update_layout call in multi-page io. I'll send a patch to fix
> that shortly.
>
After discussing this with Trond how about having
pnfs_pageio_init_{read,write} always set
pgio->pg_test = ld->pg_test
and then let the layout driver initialize its vector to
the generic pnfs_{read,write}_pg_test functions, respectively
if it requires no layout-type specific code.
(and EXPORT_SYMBOL_GPL them for the layout drivers)
Benny
> Fred
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: Smack on the head: Questions about pnfs write path
2011-05-23 17:50 ` Benny Halevy
@ 2011-05-23 17:52 ` Benny Halevy
0 siblings, 0 replies; 5+ messages in thread
From: Benny Halevy @ 2011-05-23 17:52 UTC (permalink / raw)
To: Fred Isaman; +Cc: Boaz Harrosh, Trond Myklebust, NFS list
On 2011-05-23 20:50, Benny Halevy wrote:
> On 2011-05-23 17:22, Fred Isaman wrote:
>> On Sat, May 21, 2011 at 8:16 PM, Boaz Harrosh <bharrosh@panasas.com> wrote:
>>> On 05/22/2011 02:45 AM, Boaz Harrosh wrote:
>>>>
>>>> Fred git blame points to you:
>>>>
>>>> What was the meaning of the below code:
>>>>
>>>
>>> OK Smack *ME* on the head
>>>
>>> A layout driver must have a .pg_test function else
>>> that's what happens. pNFS only for a single page.
>>> I'd say it should be opposite no?
>>>
>>
>> Right now, a driver with no pg_test function erroneously misses the
>> pnfs_update_layout call in multi-page io. I'll send a patch to fix
>> that shortly.
>>
>
> After discussing this with Trond how about having
> pnfs_pageio_init_{read,write} always set
> pgio->pg_test = ld->pg_test
>
> and then let the layout driver initialize its vector to
> the generic pnfs_{read,write}_pg_test functions, respectively
> if it requires no layout-type specific code.
> (and EXPORT_SYMBOL_GPL them for the layout drivers)
one more note: pnfs_{read,write}_pg_test should, in this model,
return 1 where they call
NFS_SERVER(pgio->pg_inode)->pnfs_curr_ld->pg_test today.
Benny
>
> Benny
>
>> Fred
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2011-05-23 17:52 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-05-21 23:45 Smack on the head: Questions about pnfs write path Boaz Harrosh
2011-05-22 0:16 ` Boaz Harrosh
2011-05-23 14:22 ` Fred Isaman
2011-05-23 17:50 ` Benny Halevy
2011-05-23 17:52 ` Benny Halevy
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).