[PATCH] NFSv4: Add lease_time and lease_expired to 'nfs4:' line of mountstats

[PATCH] NFSv4: Add lease_time and lease_expired to 'nfs4:' line of mountstats

[Dave Wysochanski]

On the NFS client there is no low-impact way to determine the nfs4
lease time or whether the lease is expired, so add these to mountstats
with times displayed in seconds.

If the lease is not expired, display lease_expired=0. Otherwise,
display lease_expired=seconds_since_expired, similar to 'age:' line
in mountstats.

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
---
 fs/nfs/super.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index c27ac96..6e52f0c 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -730,6 +730,16 @@ int nfs_show_options(struct seq_file *m, struct dentry *root)
 EXPORT_SYMBOL_GPL(nfs_show_options);
 
 #if IS_ENABLED(CONFIG_NFS_V4)
+static void show_lease(struct seq_file *m, struct nfs_server *server)
+{
+	struct nfs_client *clp = server->nfs_client;
+	unsigned long expire;
+
+	seq_printf(m, ",lease_time=%ld", clp->cl_lease_time / HZ);
+	expire = clp->cl_last_renewal + clp->cl_lease_time;
+	seq_printf(m, ",lease_expired=%ld",
+		   time_after(expire, jiffies) ?  0 : (jiffies - expire) / HZ);
+}
 #ifdef CONFIG_NFS_V4_1
 static void show_sessions(struct seq_file *m, struct nfs_server *server)
 {
@@ -838,6 +848,7 @@ int nfs_show_stats(struct seq_file *m, struct dentry *root)
 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 		show_sessions(m, nfss);
 		show_pnfs(m, nfss);
+		show_lease(m, nfss);
 	}
 #endif
 
-- 
1.8.3.1

Re: [PATCH] NFSv4: Add lease_time and lease_expired to 'nfs4:' line of mountstats

[Chuck Lever]

> On May 17, 2019, at 5:06 PM, Dave Wysochanski <dwysocha@redhat.com> wrote:
> 
> On the NFS client there is no low-impact way to determine the nfs4
> lease time or whether the lease is expired, so add these to mountstats
> with times displayed in seconds.
> 
> If the lease is not expired, display lease_expired=0. Otherwise,
> display lease_expired=seconds_since_expired, similar to 'age:' line
> in mountstats.
> 
> Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
> ---
> fs/nfs/super.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
> 
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index c27ac96..6e52f0c 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -730,6 +730,16 @@ int nfs_show_options(struct seq_file *m, struct dentry *root)
> EXPORT_SYMBOL_GPL(nfs_show_options);
> 
> #if IS_ENABLED(CONFIG_NFS_V4)
> +static void show_lease(struct seq_file *m, struct nfs_server *server)
> +{
> +	struct nfs_client *clp = server->nfs_client;
> +	unsigned long expire;
> +
> +	seq_printf(m, ",lease_time=%ld", clp->cl_lease_time / HZ);
> +	expire = clp->cl_last_renewal + clp->cl_lease_time;
> +	seq_printf(m, ",lease_expired=%ld",
> +		   time_after(expire, jiffies) ?  0 : (jiffies - expire) / HZ);
> +}
> #ifdef CONFIG_NFS_V4_1
> static void show_sessions(struct seq_file *m, struct nfs_server *server)
> {
> @@ -838,6 +848,7 @@ int nfs_show_stats(struct seq_file *m, struct dentry *root)
> 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
> 		show_sessions(m, nfss);
> 		show_pnfs(m, nfss);
> +		show_lease(m, nfss);
> 	}
> #endif
> 
> -- 
> 1.8.3.1
> 

I didn't look closely at the patch content, but IMO this is a good
observability enhancement.


--
Chuck Lever

Re: [PATCH] NFSv4: Add lease_time and lease_expired to 'nfs4:' line of mountstats

[Dave Wysochanski]

On Mon, 2019-05-20 at 11:10 -0400, Chuck Lever wrote:
> > On May 17, 2019, at 5:06 PM, Dave Wysochanski <dwysocha@redhat.com>
> > wrote:
> > 
> > On the NFS client there is no low-impact way to determine the nfs4
> > lease time or whether the lease is expired, so add these to
> > mountstats
> > with times displayed in seconds.
> > 
> > If the lease is not expired, display lease_expired=0. Otherwise,
> > display lease_expired=seconds_since_expired, similar to 'age:' line
> > in mountstats.
> > 
> > Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
> > ---
> > fs/nfs/super.c | 11 +++++++++++
> > 1 file changed, 11 insertions(+)
> > 
> > diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> > index c27ac96..6e52f0c 100644
> > --- a/fs/nfs/super.c
> > +++ b/fs/nfs/super.c
> > @@ -730,6 +730,16 @@ int nfs_show_options(struct seq_file *m,
> > struct dentry *root)
> > EXPORT_SYMBOL_GPL(nfs_show_options);
> > 
> > #if IS_ENABLED(CONFIG_NFS_V4)
> > +static void show_lease(struct seq_file *m, struct nfs_server
> > *server)
> > +{
> > +	struct nfs_client *clp = server->nfs_client;
> > +	unsigned long expire;
> > +
> > +	seq_printf(m, ",lease_time=%ld", clp->cl_lease_time / HZ);
> > +	expire = clp->cl_last_renewal + clp->cl_lease_time;
> > +	seq_printf(m, ",lease_expired=%ld",
> > +		   time_after(expire, jiffies) ?  0 : (jiffies -
> > expire) / HZ);
> > +}
> > #ifdef CONFIG_NFS_V4_1
> > static void show_sessions(struct seq_file *m, struct nfs_server
> > *server)
> > {
> > @@ -838,6 +848,7 @@ int nfs_show_stats(struct seq_file *m, struct
> > dentry *root)
> > 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
> > 		show_sessions(m, nfss);
> > 		show_pnfs(m, nfss);
> > +		show_lease(m, nfss);
> > 	}
> > #endif
> > 
> > -- 
> > 1.8.3.1
> > 
> 
> I didn't look closely at the patch content, but IMO this is a good
> observability enhancement.
> 
> 
> 

Thanks Chuck.  Trond or Anna do you have any concerns about this patch?

I didn't bump NFS_IOSTAT_VERS as I understand that only covers the
counts not the other lines in nfs_show_stats, correct?

Thanks.