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[34.92.28.173]) by smtp.gmail.com with ESMTPSA id h20sm2061216pgv.23.2020.11.04.03.33.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 04 Nov 2020 03:33:50 -0800 (PST) Subject: Re: [PATCH 2/2] NFS: Limit the number of retries To: Trond Myklebust , "anna.schumaker@netapp.com" Cc: "chenwenle@huawei.com" , "linux-nfs@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "nixiaoming@huawei.com" References: <20201102162438.14034-1-chenwenle@huawei.com> <20201102162438.14034-3-chenwenle@huawei.com> <8db50c039cb8b8325bb428c60ff005b899654fb4.camel@hammerspace.com> From: Wenle Chen Message-ID: Date: Wed, 4 Nov 2020 19:33:48 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <8db50c039cb8b8325bb428c60ff005b899654fb4.camel@hammerspace.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Trond Myklebust 於 2020/11/3 上午1:45 寫道: > On Tue, 2020-11-03 at 00:24 +0800, Wenle Chen wrote: >>   We can't wait forever, even if the state >> is always delayed. >> >> Signed-off-by: Wenle Chen >> --- >>  fs/nfs/nfs4proc.c | 4 +++- >>  1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c >> index f6b5dc792b33..bb2316bf13f6 100644 >> --- a/fs/nfs/nfs4proc.c >> +++ b/fs/nfs/nfs4proc.c >> @@ -7390,15 +7390,17 @@ int nfs4_lock_delegation_recall(struct >> file_lock *fl, struct nfs4_state *state, >>  { >>         struct nfs_server *server = NFS_SERVER(state->inode); >>         int err; >> +       int retry = 3; >> >>         err = nfs4_set_lock_state(state, fl); >>         if (err != 0) >>                 return err; >>         do { >>                 err = _nfs4_do_setlk(state, F_SETLK, fl, >> NFS_LOCK_NEW); >> -               if (err != -NFS4ERR_DELAY) >> +               if (err != -NFS4ERR_DELAY || retry == 0) >>                         break; >>                 ssleep(1); >> +               --retry; >>         } while (1); >>         return nfs4_handle_delegation_recall_error(server, state, >> stateid, fl, err); >>  } > > This patch will just cause the locks to be silently lost, no? > This loop was introduced in commit 3d7a9520f0c3e to simplify the delay retry loop. Before this, the function nfs4_lock_delegation_recall would return a -EAGAIN to do a whole retry loop. When we retried three times and waited three seconds, it was still in delay. I think we can get a whole loop and check the other points if it was changed or not. It is just a proposal.