From: dai.ngo@oracle.com
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: chuck.lever@oracle.com, linux-nfs@vger.kernel.org
Subject: Re: [PATCH RFC 1/1] nfsd: Initial implementation of NFSv4 Courteous Server
Date: Mon, 28 Jun 2021 16:39:51 -0700 [thread overview]
Message-ID: <dc71d572-d108-bcfc-e264-d96ef0de1b36@oracle.com> (raw)
In-Reply-To: <20210628202331.GC6776@fieldses.org>
On 6/28/21 1:23 PM, J. Bruce Fields wrote:
> On Thu, Jun 03, 2021 at 02:14:38PM -0400, Dai Ngo wrote:
>> @@ -6875,7 +6947,12 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>> case -EAGAIN: /* conflock holds conflicting lock */
>> status = nfserr_denied;
>> dprintk("NFSD: nfsd4_lock: conflicting lock found!\n");
>> - nfs4_set_lock_denied(conflock, &lock->lk_denied);
>> +
>> + /* try again if conflict with courtesy client */
>> + if (nfs4_set_lock_denied(conflock, &lock->lk_denied) == -EAGAIN && !retried) {
>> + retried = true;
>> + goto again;
>> + }
> Ugh, apologies, this was my idea, but I just noticed it only handles conflicts
> from other NFSv4 clients. The conflicting lock could just as well come from
> NLM or a local process. So we need cooperation from the common locks.c code.
>
> I'm not sure what to suggest....
>
> Maybe something like:
>
> @@ -1159,6 +1159,7 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request,
> }
>
> percpu_down_read(&file_rwsem);
> +retry:
> spin_lock(&ctx->flc_lock);
> /*
> * New lock request. Walk all POSIX locks and look for conflicts. If
> @@ -1169,6 +1170,11 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request,
> list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
> if (!posix_locks_conflict(request, fl))
> continue;
> + if (fl->fl_lops->fl_expire_lock(fl, 1)) {
> + spin_unlock(&ctx->flc_lock);
> + fl->fl_lops->fl_expire_locks(fl, 0);
> + goto retry;
> + }
> if (conflock)
> locks_copy_conflock(conflock, fl);
> error = -EAGAIN;
>
>
> where ->fl_expire_lock is a new lock callback with second argument "check"
> where:
>
> check = 1 means: just check whether this lock could be freed
> check = 0 means: go ahead and free this lock if you can
Thanks Bruce, I will look into this approach.
-Dai
>
> --b.
next prev parent reply other threads:[~2021-06-28 23:40 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-03 18:14 [PATCH RFC 1/1] nfsd: Initial implementation of NFSv4 Courteous Server Dai Ngo
2021-06-11 8:42 ` dai.ngo
2021-06-16 16:02 ` J. Bruce Fields
2021-06-16 16:32 ` Chuck Lever III
2021-06-16 19:25 ` dai.ngo
2021-06-16 19:29 ` Chuck Lever III
2021-06-16 20:30 ` Bruce Fields
2021-06-16 19:17 ` dai.ngo
2021-06-16 19:19 ` Calum Mackay
2021-06-16 19:27 ` dai.ngo
2021-06-24 14:02 ` J. Bruce Fields
2021-06-24 19:50 ` dai.ngo
2021-06-24 20:36 ` J. Bruce Fields
2021-06-28 20:23 ` J. Bruce Fields
2021-06-28 23:39 ` dai.ngo [this message]
2021-06-29 4:40 ` dai.ngo
2021-06-30 1:35 ` J. Bruce Fields
2021-06-30 8:41 ` dai.ngo
2021-06-30 14:52 ` J. Bruce Fields
2021-06-30 17:51 ` dai.ngo
2021-06-30 18:05 ` J. Bruce Fields
2021-06-30 18:49 ` dai.ngo
2021-06-30 18:55 ` J. Bruce Fields
2021-06-30 19:13 ` dai.ngo
2021-06-30 19:24 ` J. Bruce Fields
2021-06-30 23:48 ` dai.ngo
2021-07-01 1:16 ` J. Bruce Fields
2021-06-30 15:13 ` J. Bruce Fields
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