linux-kernel - Re: [PATCH v2 2/2] ceph: wait the first reply of inflight unlink/rmdir

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Date:   Tue, 17 May 2022 19:59:34 +0800
From:   Xiubo Li <xiubli@...hat.com>
To:     Jeff Layton <jlayton@...nel.org>, viro@...iv.linux.org.uk
Cc:     idryomov@...il.com, vshankar@...hat.com,
        ceph-devel@...r.kernel.org, arnd@...db.de, mcgrof@...nel.org,
        akpm@...ux-foundation.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel test robot <lkp@...el.com>
Subject: Re: [PATCH v2 2/2] ceph: wait the first reply of inflight
 unlink/rmdir


On 5/17/22 7:54 PM, Jeff Layton wrote:
> On Tue, 2022-05-17 at 19:49 +0800, Xiubo Li wrote:
>> On 5/17/22 7:35 PM, Jeff Layton wrote:
>>> On Tue, 2022-05-17 at 09:03 +0800, Xiubo Li wrote:
>>>> In async unlink case the kclient won't wait for the first reply
>>>> from MDS and just drop all the links and unhash the dentry and then
>>>> succeeds immediately.
>>>>
>>>> For any new create/link/rename,etc requests followed by using the
>>>> same file names we must wait for the first reply of the inflight
...
>>> I doubt you need this large a hashtable, particularly given that this is
>>> per-superblock. In most cases, we'll just have a few of these in flight
>>> at a time.
>> A global hashtable ? And set the order to 8 ?
> Per-sb is fine, IMO. 6-8 bits sounds reasonable.

Sure, let's use 8. From my snaptest I can see there had a lot of 
dentries in the hashtable at the same time some times.

-- Xiubo