diff mbox

[1/2] nfs: Only update callback sequnce id when CB_SEQUENCE success

Message ID 556D8C66.8080203@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kinglong Mee June 2, 2015, 10:58 a.m. UTC
When testing pnfs layout, nfsd got error NFS4ERR_SEQ_MISORDERED.
It is caused by nfs return NFS4ERR_DELAY before validate_seqid(),
don't update the sequnce id, but nfsd updates the sequnce id !!!

According to RFC5661 20.9.3,
" If CB_SEQUENCE returns an error, then the state of the slot
  (sequence ID, cached reply) MUST NOT change. "

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
---
 fs/nfs/callback_proc.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

Comments

Kinglong Mee June 11, 2015, 1:38 a.m. UTC | #1
ping .... 

On 6/2/2015 6:58 PM, Kinglong Mee wrote:
> When testing pnfs layout, nfsd got error NFS4ERR_SEQ_MISORDERED.
> It is caused by nfs return NFS4ERR_DELAY before validate_seqid(),
> don't update the sequnce id, but nfsd updates the sequnce id !!!
> 
> According to RFC5661 20.9.3,
> " If CB_SEQUENCE returns an error, then the state of the slot
>   (sequence ID, cached reply) MUST NOT change. "
> 
> Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
> ---
>  fs/nfs/callback_proc.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
> index 197806f..7e9653a 100644
> --- a/fs/nfs/callback_proc.c
> +++ b/fs/nfs/callback_proc.c
> @@ -327,10 +327,8 @@ validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
>  	dprintk("%s slot table seqid: %u\n", __func__, slot->seq_nr);
>  
>  	/* Normal */
> -	if (likely(args->csa_sequenceid == slot->seq_nr + 1)) {
> -		slot->seq_nr++;
> +	if (likely(args->csa_sequenceid == slot->seq_nr + 1))
>  		goto out_ok;
> -	}
>  
>  	/* Replay */
>  	if (args->csa_sequenceid == slot->seq_nr) {
> @@ -418,6 +416,7 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
>  			      struct cb_process_state *cps)
>  {
>  	struct nfs4_slot_table *tbl;
> +	struct nfs4_slot *slot;
>  	struct nfs_client *clp;
>  	int i;
>  	__be32 status = htonl(NFS4ERR_BADSESSION);
> @@ -429,7 +428,9 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
>  
>  	if (!(clp->cl_session->flags & SESSION4_BACK_CHAN))
>  		goto out;
> +
>  	tbl = &clp->cl_session->bc_slot_table;
> +	slot = tbl->slots + args->csa_slotid;
>  
>  	spin_lock(&tbl->slot_tbl_lock);
>  	/* state manager is resetting the session */
> @@ -444,7 +445,7 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
>  		goto out;
>  	}
>  
> -	status = validate_seqid(&clp->cl_session->bc_slot_table, args);
> +	status = validate_seqid(tbl, args);
>  	spin_unlock(&tbl->slot_tbl_lock);
>  	if (status)
>  		goto out;
> @@ -468,6 +469,13 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
>  	res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
>  	res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
>  
> +	/*
> +	 * RFC5661 20.9.3
> +	 * If CB_SEQUENCE returns an error, then the state of the slot
> +	 * (sequence ID, cached reply) MUST NOT change.
> +	 */
> +	slot->seq_nr++;
> +
>  out:
>  	cps->clp = clp; /* put in nfs4_callback_compound */
>  	for (i = 0; i < args->csa_nrclists; i++)
> 
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Christoph Hellwig June 11, 2015, 8:20 a.m. UTC | #2
Hi Kinglong,

when we last brought up this issue the recommendation was to follow
the model in the clients nfs41_sequence_done() which handles even
more corner cases.  Given that my previous fixes in that area were
just a bandaid I probably shouldn't complain about piece mail handling,
but if you have a little spare time available implementing the full
set of checks might be worthwhile.

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Kinglong Mee June 11, 2015, 9:13 a.m. UTC | #3
On 6/11/2015 4:20 PM, Christoph Hellwig wrote:
> Hi Kinglong,
> 
> when we last brought up this issue the recommendation was to follow
> the model in the clients nfs41_sequence_done() which handles even
> more corner cases.  Given that my previous fixes in that area were
> just a bandaid I probably shouldn't complain about piece mail handling,
> but if you have a little spare time available implementing the full
> set of checks might be worthwhile.

Thank you for your comments.

I have see your patches sits "nfsd: callback fixes". You said process as
nfs41_sequence_done() for handling error cases is server's logical.

Those two patches for NFS client are fix two bugs.

The first one is fix that between validate_seqid() nfs can return error
to nfs server. NFS server cannot make sure whether NFS client has update
the sequence ID.

Also, according to RFC, "If CB_SEQUENCE returns an error, then the state
of the slot (sequence ID, cached reply) MUST NOT change.",
so that this this patch is out.

The second for nfs is fix the initialize problem of cb_sequenceres
when meeting NFS4ERR_RETRY_UNCACHED_REP.

And, other two patches for nfsd, 
The first is fix a infinite loop caused by your last patch I meet.
The second is as you said following to nfs41_sequence_done() maybe better.

thanks
Kinglong Mee
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diff mbox

Patch

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 197806f..7e9653a 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -327,10 +327,8 @@  validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
 	dprintk("%s slot table seqid: %u\n", __func__, slot->seq_nr);
 
 	/* Normal */
-	if (likely(args->csa_sequenceid == slot->seq_nr + 1)) {
-		slot->seq_nr++;
+	if (likely(args->csa_sequenceid == slot->seq_nr + 1))
 		goto out_ok;
-	}
 
 	/* Replay */
 	if (args->csa_sequenceid == slot->seq_nr) {
@@ -418,6 +416,7 @@  __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
 			      struct cb_process_state *cps)
 {
 	struct nfs4_slot_table *tbl;
+	struct nfs4_slot *slot;
 	struct nfs_client *clp;
 	int i;
 	__be32 status = htonl(NFS4ERR_BADSESSION);
@@ -429,7 +428,9 @@  __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
 
 	if (!(clp->cl_session->flags & SESSION4_BACK_CHAN))
 		goto out;
+
 	tbl = &clp->cl_session->bc_slot_table;
+	slot = tbl->slots + args->csa_slotid;
 
 	spin_lock(&tbl->slot_tbl_lock);
 	/* state manager is resetting the session */
@@ -444,7 +445,7 @@  __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
 		goto out;
 	}
 
-	status = validate_seqid(&clp->cl_session->bc_slot_table, args);
+	status = validate_seqid(tbl, args);
 	spin_unlock(&tbl->slot_tbl_lock);
 	if (status)
 		goto out;
@@ -468,6 +469,13 @@  __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
 	res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
 	res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
 
+	/*
+	 * RFC5661 20.9.3
+	 * If CB_SEQUENCE returns an error, then the state of the slot
+	 * (sequence ID, cached reply) MUST NOT change.
+	 */
+	slot->seq_nr++;
+
 out:
 	cps->clp = clp; /* put in nfs4_callback_compound */
 	for (i = 0; i < args->csa_nrclists; i++)