diff mbox series

[v3,2/2] NFSD: add counter for write delegation recall due to conflict with GETATTR

Message ID 1685500507-23598-3-git-send-email-dai.ngo@oracle.com (mailing list archive)
State Handled Elsewhere, archived
Headers show
Series NFSD: recall write delegation on GETATTR conflict | expand

Commit Message

Dai Ngo May 31, 2023, 2:35 a.m. UTC 
Add counter to keep track of how many times write delegations are
recalled due to conflict with GETATTR.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 1 +
 fs/nfsd/stats.c     | 2 ++
 fs/nfsd/stats.h     | 7 +++++++
 3 files changed, 10 insertions(+)

Comments

Jeff Layton May 31, 2023, 10:12 a.m. UTC | #1 
On Tue, 2023-05-30 at 19:35 -0700, Dai Ngo wrote:
> Add counter to keep track of how many times write delegations are
> recalled due to conflict with GETATTR.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
>  fs/nfsd/nfs4state.c | 1 +
>  fs/nfsd/stats.c     | 2 ++
>  fs/nfsd/stats.h     | 7 +++++++
>  3 files changed, 10 insertions(+)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 29ed2e72b665..cba27dfa39e8 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -8402,6 +8402,7 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct inode *inode)
>  			}
>  break_lease:
>  			spin_unlock(&ctx->flc_lock);
> +			nfsd_stats_wdeleg_getattr_inc();
>  			status = nfserrno(nfsd_open_break_lease(inode, NFSD_MAY_READ));
>  			if (status != nfserr_jukebox ||
>  					!nfsd_wait_for_delegreturn(rqstp, inode))
> diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
> index 777e24e5da33..63797635e1c3 100644
> --- a/fs/nfsd/stats.c
> +++ b/fs/nfsd/stats.c
> @@ -65,6 +65,8 @@ static int nfsd_show(struct seq_file *seq, void *v)
>  		seq_printf(seq, " %lld",
>  			   percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_NFS4_OP(i)]));
>  	}
> +	seq_printf(seq, "\nwdeleg_getattr %lld",
> +		percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_WDELEG_GETATTR]));
>  
>  	seq_putc(seq, '\n');
>  #endif
> diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h
> index 9b43dc3d9991..cf5524e7ca06 100644
> --- a/fs/nfsd/stats.h
> +++ b/fs/nfsd/stats.h
> @@ -22,6 +22,7 @@ enum {
>  	NFSD_STATS_FIRST_NFS4_OP,	/* count of individual nfsv4 operations */
>  	NFSD_STATS_LAST_NFS4_OP = NFSD_STATS_FIRST_NFS4_OP + LAST_NFS4_OP,
>  #define NFSD_STATS_NFS4_OP(op)	(NFSD_STATS_FIRST_NFS4_OP + (op))
> +	NFSD_STATS_WDELEG_GETATTR,	/* count of getattr conflict with wdeleg */
>  #endif
>  	NFSD_STATS_COUNTERS_NUM
>  };
> @@ -93,4 +94,10 @@ static inline void nfsd_stats_drc_mem_usage_sub(struct nfsd_net *nn, s64 amount)
>  	percpu_counter_sub(&nn->counter[NFSD_NET_DRC_MEM_USAGE], amount);
>  }
>  
> +#ifdef CONFIG_NFSD_V4
> +static inline void nfsd_stats_wdeleg_getattr_inc(void)
> +{
> +	percpu_counter_inc(&nfsdstats.counter[NFSD_STATS_WDELEG_GETATTR]);
> +}
> +#endif
>  #endif /* _NFSD_STATS_H */

Personally, I think it would still be simpler to just do a CB_GETATTR.
We are issuing a callback in either case, but recalling the delegation
seems like a less optimal outcome.

Still for an interim step, this is fine...

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Chuck Lever May 31, 2023, 2:11 p.m. UTC | #2 
> On May 31, 2023, at 6:12 AM, Jeff Layton <jlayton@kernel.org> wrote:
> 
> On Tue, 2023-05-30 at 19:35 -0700, Dai Ngo wrote:
>> Add counter to keep track of how many times write delegations are
>> recalled due to conflict with GETATTR.
>> 
>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>> ---
>> fs/nfsd/nfs4state.c | 1 +
>> fs/nfsd/stats.c     | 2 ++
>> fs/nfsd/stats.h     | 7 +++++++
>> 3 files changed, 10 insertions(+)
>> 
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index 29ed2e72b665..cba27dfa39e8 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -8402,6 +8402,7 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct inode *inode)
>> }
>> break_lease:
>> spin_unlock(&ctx->flc_lock);
>> + nfsd_stats_wdeleg_getattr_inc();
>> status = nfserrno(nfsd_open_break_lease(inode, NFSD_MAY_READ));
>> if (status != nfserr_jukebox ||
>> !nfsd_wait_for_delegreturn(rqstp, inode))
>> diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
>> index 777e24e5da33..63797635e1c3 100644
>> --- a/fs/nfsd/stats.c
>> +++ b/fs/nfsd/stats.c
>> @@ -65,6 +65,8 @@ static int nfsd_show(struct seq_file *seq, void *v)
>> seq_printf(seq, " %lld",
>>    percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_NFS4_OP(i)]));
>> }
>> + seq_printf(seq, "\nwdeleg_getattr %lld",
>> + percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_WDELEG_GETATTR]));
>> 
>> seq_putc(seq, '\n');
>> #endif
>> diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h
>> index 9b43dc3d9991..cf5524e7ca06 100644
>> --- a/fs/nfsd/stats.h
>> +++ b/fs/nfsd/stats.h
>> @@ -22,6 +22,7 @@ enum {
>> NFSD_STATS_FIRST_NFS4_OP, /* count of individual nfsv4 operations */
>> NFSD_STATS_LAST_NFS4_OP = NFSD_STATS_FIRST_NFS4_OP + LAST_NFS4_OP,
>> #define NFSD_STATS_NFS4_OP(op) (NFSD_STATS_FIRST_NFS4_OP + (op))
>> + NFSD_STATS_WDELEG_GETATTR, /* count of getattr conflict with wdeleg */
>> #endif
>> NFSD_STATS_COUNTERS_NUM
>> };
>> @@ -93,4 +94,10 @@ static inline void nfsd_stats_drc_mem_usage_sub(struct nfsd_net *nn, s64 amount)
>> percpu_counter_sub(&nn->counter[NFSD_NET_DRC_MEM_USAGE], amount);
>> }
>> 
>> +#ifdef CONFIG_NFSD_V4
>> +static inline void nfsd_stats_wdeleg_getattr_inc(void)
>> +{
>> + percpu_counter_inc(&nfsdstats.counter[NFSD_STATS_WDELEG_GETATTR]);
>> +}
>> +#endif
>> #endif /* _NFSD_STATS_H */
> 
> Personally, I think it would still be simpler to just do a CB_GETATTR.
> We are issuing a callback in either case, but recalling the delegation
> seems like a less optimal outcome.

An NFS server has to support either CB_RECALL, or it has to
support CB_GETATTR and fall back to CB_RECALL. Some clients
might not support CB_GETATTR, after all.

Either way NFSD has to handle CB_RECALL properly in this case.


> Still for an interim step, this is fine...
> 
> Reviewed-by: Jeff Layton <jlayton@kernel.org>


--
Chuck Lever
diff mbox series

Patch

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 29ed2e72b665..cba27dfa39e8 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -8402,6 +8402,7 @@  nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct inode *inode)
 			}
 break_lease:
 			spin_unlock(&ctx->flc_lock);
+			nfsd_stats_wdeleg_getattr_inc();
 			status = nfserrno(nfsd_open_break_lease(inode, NFSD_MAY_READ));
 			if (status != nfserr_jukebox ||
 					!nfsd_wait_for_delegreturn(rqstp, inode))
diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
index 777e24e5da33..63797635e1c3 100644
--- a/fs/nfsd/stats.c
+++ b/fs/nfsd/stats.c
@@ -65,6 +65,8 @@  static int nfsd_show(struct seq_file *seq, void *v)
 		seq_printf(seq, " %lld",
 			   percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_NFS4_OP(i)]));
 	}
+	seq_printf(seq, "\nwdeleg_getattr %lld",
+		percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_WDELEG_GETATTR]));
 
 	seq_putc(seq, '\n');
 #endif
diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h
index 9b43dc3d9991..cf5524e7ca06 100644
--- a/fs/nfsd/stats.h
+++ b/fs/nfsd/stats.h
@@ -22,6 +22,7 @@  enum {
 	NFSD_STATS_FIRST_NFS4_OP,	/* count of individual nfsv4 operations */
 	NFSD_STATS_LAST_NFS4_OP = NFSD_STATS_FIRST_NFS4_OP + LAST_NFS4_OP,
 #define NFSD_STATS_NFS4_OP(op)	(NFSD_STATS_FIRST_NFS4_OP + (op))
+	NFSD_STATS_WDELEG_GETATTR,	/* count of getattr conflict with wdeleg */
 #endif
 	NFSD_STATS_COUNTERS_NUM
 };
@@ -93,4 +94,10 @@  static inline void nfsd_stats_drc_mem_usage_sub(struct nfsd_net *nn, s64 amount)
 	percpu_counter_sub(&nn->counter[NFSD_NET_DRC_MEM_USAGE], amount);
 }
 
+#ifdef CONFIG_NFSD_V4
+static inline void nfsd_stats_wdeleg_getattr_inc(void)
+{
+	percpu_counter_inc(&nfsdstats.counter[NFSD_STATS_WDELEG_GETATTR]);
+}
+#endif
 #endif /* _NFSD_STATS_H */