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From: Benjamin Coddington <bcodding@redhat.com>
To: Anna Schumaker <anna@kernel.org>
Cc: linux-nfs@vger.kernel.org, trond.myklebust@hammerspace.com
Subject: Re: [PATCH] NFS: Fix READ_PLUS when server doesn't support
 OP_READ_PLUS
Date: Fri, 26 Apr 2024 07:43:26 -0400
Message-ID: <A9C3D12F-3E5E-4DE5-9A56-ECB7EDDB0AD0@redhat.com>
In-Reply-To: <20240425202429.439014-1-anna@kernel.org>
References: <20240425202429.439014-1-anna@kernel.org>
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On 25 Apr 2024, at 16:24, Anna Schumaker wrote:

> From: Anna Schumaker <Anna.Schumaker@Netapp.com>
>
> Olga showed me a case where the client was sending multiple READ_PLUS
> calls to the server in parallel, and the server replied
> NFS4ERR_OPNOTSUPP to each. The client would fall back to READ for the
> first reply, but fail to retry the other calls.
>
> I fix this by removing the test for NFS_CAP_READ_PLUS in
> nfs4_read_plus_not_supported(). This allows us to reschedule any
> READ_PLUS call that has a NFS4ERR_OPNOTSUPP return value, even after the
> capability has been cleared.
>
> Reported-by: Olga Kornievskaia <kolga@netapp.com>
> Fixes: c567552612ec ("NFS: Add READ_PLUS data segment support")
> Cc: stable@vger.kernel.org # v5.10+
> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Reviewed-by: Benjamin Coddington <bcodding@redhat.com>

Ben

> ---
>  fs/nfs/nfs4proc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index ea390db94b62..c93c12063b3a 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -5456,7 +5456,7 @@ static bool nfs4_read_plus_not_supported(struct rpc_task *task,
>  	struct rpc_message *msg = &task->tk_msg;
>
>  	if (msg->rpc_proc == &nfs4_procedures[NFSPROC4_CLNT_READ_PLUS] &&
> -	    server->caps & NFS_CAP_READ_PLUS && task->tk_status == -ENOTSUPP) {
> +	    task->tk_status == -ENOTSUPP) {
>  		server->caps &= ~NFS_CAP_READ_PLUS;
>  		msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ];
>  		rpc_restart_call_prepare(task);
> -- 
> 2.44.0