[Gluster-devel] a link issue maybe introduced in a bug fix " Don't let NFS cache stat after writes"

[Lian, George (NSB - CN/Hangzhou)]

Hi,

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

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 at redhat.com>
Cc: Zhou, Cynthia (NSB - CN/Hangzhou) <cynthia.zhou at nokia-sbell.com>; Gluster-devel at gluster.org; Li, Deqian (NSB - CN/Hangzhou) <deqian.li at nokia-sbell.com>; Sun, Ping (NSB - CN/Hangzhou) <ping.sun at nokia-sbell.com>
Subject: RE: [Gluster-devel] 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 at gluster.org<mailto:gluster-devel-bounces at gluster.org> [mailto:gluster-devel-bounces at gluster.org] On Behalf Of Pranith Kumar Karampuri
Sent: Thursday, January 11, 2018 12:39 PM
To: Lian, George (NSB - CN/Hangzhou) <george.lian at nokia-sbell.com<mailto:george.lian at nokia-sbell.com>>
Cc: Zhou, Cynthia (NSB - CN/Hangzhou) <cynthia.zhou at nokia-sbell.com<mailto:cynthia.zhou at nokia-sbell.com>>; Gluster-devel at gluster.org<mailto:Gluster-devel at gluster.org>; Li, Deqian (NSB - CN/Hangzhou) <deqian.li at nokia-sbell.com<mailto:deqian.li at nokia-sbell.com>>; Sun, Ping (NSB - CN/Hangzhou) <ping.sun at nokia-sbell.com<mailto:ping.sun at nokia-sbell.com>>
Subject: Re: [Gluster-devel] 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 at nokia-sbell.com<mailto:george.lian at nokia-sbell.com>> 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 at gluster.org<mailto:gluster-devel-bounces at gluster.org> [mailto:gluster-devel-bounces at gluster.org<mailto:gluster-devel-bounces at gluster.org>] On Behalf Of Pranith Kumar Karampuri
Sent: Wednesday, January 10, 2018 8:08 PM
To: Lian, George (NSB - CN/Hangzhou) <george.lian at nokia-sbell.com<mailto:george.lian at nokia-sbell.com>>
Cc: Zhou, Cynthia (NSB - CN/Hangzhou) <cynthia.zhou at nokia-sbell.com<mailto:cynthia.zhou at nokia-sbell.com>>; Zhong, Hua (NSB - CN/Hangzhou) <hua.zhong at nokia-sbell.com<mailto:hua.zhong at nokia-sbell.com>>; Li, Deqian (NSB - CN/Hangzhou) <deqian.li at nokia-sbell.com<mailto:deqian.li at nokia-sbell.com>>; Gluster-devel at gluster.org<mailto:Gluster-devel at gluster.org>; Sun, Ping (NSB - CN/Hangzhou) <ping.sun at nokia-sbell.com<mailto:ping.sun at nokia-sbell.com>>
Subject: Re: [Gluster-devel] 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 at nokia-sbell.com<mailto:george.lian at nokia-sbell.com>> 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
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