Re: a link issue maybe introduced in a bug fix " Don't let NFS cache stat after writes"

Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx> · Wed, 17 Jan 2018 16:56:40 +0530

On Mon, Jan 15, 2018 at 1:55 PM, Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx> wrote:

On Mon, Jan 15, 2018 at 8:46 AM, Lian, George (NSB - CN/Hangzhou) <george.lian@xxxxxxxxxxxxxxx> wrote:

Hi,

Have you reproduced this issue? If yes, could you please confirm whether it is an issue or not?

Hi,
       I tried recreating this on my laptop and on both master and 3.12 and I am not able to recreate the issue :-(.
Here is the execution log: https://paste.fedoraproject.org/paste/-csXUKrwsbrZAVW1KzggQQ
Since I was doing this on my laptop, I changed shutting down of the replica to killing the brick process to simulate this test.
Let me know if I missed something.

Sorry, I am held up with some issue at work, so I think I will get some time day after tomorrow to look at this. In the mean time I am adding more people who know about afr to see if they get a chance to work on this before me.

And if it is an issue,  do you have any solution for this issue?

Thanks & Best Regards,
George

From: Lian, George (NSB - CN/Hangzhou)

Sent: Thursday, January 11, 2018 2:01 PM

To: Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx>

Cc: Zhou, Cynthia (NSB - CN/Hangzhou) <cynthia.zhou@xxxxxxxxxxxxxxx>; Gluster-devel@xxxxxxxxxxx; Li, Deqian (NSB - CN/Hangzhou) <deqian.li@xxxxxxxxxxxxxxx>; Sun, Ping (NSB - CN/Hangzhou) <ping.sun@xxxxxxxxxxxxxxx>

Subject: RE:  a link issue maybe introduced in a bug fix " Don't let NFS cache stat after writes"

Hi,

Please see detail test step on
https://bugzilla.redhat.com/show_bug.cgi?id=1531457

How reproducible:

Steps to Reproduce:
1.create a volume name "test" with replicated

2.set volume option cluster.consistent-metadata with on: 

  gluster v set test cluster.consistent-metadata on
3. mount volume test on client on /mnt/test
4. create a file aaa size more than 1 byte
   echo "1234567890" >/mnt/test/aaa
5. shutdown a replicat node, let's say sn-1, only let sn-0 worked
6. cp /mnt/test/aaa /mnt/test/bbb; link /mnt/test/bbb /mnt/test/ccc

BRs
George

From:
gluster-devel-bounces@gluster.org [mailto:gluster-devel-bounces@gluster.org]
On Behalf Of Pranith Kumar Karampuri

Sent: Thursday, January 11, 2018 12:39 PM

To: Lian, George (NSB - CN/Hangzhou) <george.lian@xxxxxxxxxxxxxxx>

Cc: Zhou, Cynthia (NSB - CN/Hangzhou) <cynthia.zhou@xxxxxxxxxxxxxxx>;
Gluster-devel@xxxxxxxxxxx; Li, Deqian (NSB - CN/Hangzhou) <deqian.li@xxxxxxxxxxxxxxx>; Sun, Ping (NSB - CN/Hangzhou) <ping.sun@xxxxxxxxxxxxxxx>

Subject: Re:  a link issue maybe introduced in a bug fix " Don't let NFS cache stat after writes"

On Thu, Jan 11, 2018 at 6:35 AM, Lian, George (NSB - CN/Hangzhou) <george.lian@xxxxxxxxxxxxxxx> wrote:

Hi,
>>> In which protocol are you seeing this issue? Fuse/NFS/SMB?
It is fuse, within mountpoint by
“mount -t glusterfs 
…“ command.

Could you let me know the test you did so that I can try to re-create and see what exactly is going on?

Configuration of the volume and the steps to re-create the issue you are seeing would be helpful in debugging the issue further.

Thanks & Best Regards,
George

From:
gluster-devel-bounces@gluster.org [mailto:gluster-devel-bounces@gluster.org]
On Behalf Of Pranith Kumar Karampuri

Sent: Wednesday, January 10, 2018 8:08 PM

To: Lian, George (NSB - CN/Hangzhou) <george.lian@xxxxxxxxxxxxxxx>

Cc: Zhou, Cynthia (NSB - CN/Hangzhou) <cynthia.zhou@xxxxxxxxxxxxxxx>; Zhong, Hua (NSB - CN/Hangzhou) <hua.zhong@xxxxxxxxxxxxxxx>;
 Li, Deqian (NSB - CN/Hangzhou) <deqian.li@xxxxxxxxxxxxxxx>;
Gluster-devel@xxxxxxxxxxx; Sun, Ping (NSB - CN/Hangzhou) <ping.sun@xxxxxxxxxxxxxxx>

Subject: Re:  a link issue maybe introduced in a bug fix " Don't let NFS cache stat after writes"

On Wed, Jan 10, 2018 at 11:09 AM, Lian, George (NSB - CN/Hangzhou) <george.lian@xxxxxxxxxxxxxxx>
 wrote:

Hi, Pranith Kumar,

I has create a bug on Bugzilla
https://bugzilla.redhat.com/show_bug.cgi?id=1531457
After my investigation for this link issue, I suppose your changes on afr-dir-write.c with issue " Don't let NFS cache stat after writes" , your fix is like:
--------------------------------------
       if (afr_txn_nothing_failed (frame, this)) {
                        /*if it did pre-op, it will do post-op changing ctime*/
                        if (priv->consistent_metadata &&
                            afr_needs_changelog_update (local))
                                afr_zero_fill_stat (local);
                        local->transaction.unwind (frame, this);

                }

In the above fix, it set the ia_nlink to
‘0’ if option consistent-metadata is set to
“on”.
And hard link a file with which just created will lead to an error, and the error is caused in kernel function
“vfs_link”:
if (inode->i_nlink == 0 && !(inode->i_state & I_LINKABLE))
             error =  -ENOENT;

could you please have a check and give some comments here?

When stat is "zero filled", understanding is that the higher layer protocol doesn't send stat value to the kernel and a separate lookup is sent by the kernel
 to get the latest stat value. In which protocol are you seeing this issue? Fuse/NFS/SMB?

Thanks & Best Regards,
George

-- 

Pranith

-- 

Pranith

-- 
Pranith

-- 
Pranith

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