[v2,1/8] ceph: add global dentry lease metric support
diff mbox series

Message ID 20200108104152.28468-2-xiubli@redhat.com
State New
Headers show
Series
  • ceph: add perf metrics support
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Commit Message

Xiubo Li Jan. 8, 2020, 10:41 a.m. UTC
From: Xiubo Li <xiubli@redhat.com>

For the dentry lease we will only count the hit/miss info triggered
from the vfs calls, for the cases like request reply handling and
perodically ceph_trim_dentries() we will ignore them.

Currently only the debugfs is support:

The output will be:

item          total           miss            hit
-------------------------------------------------
d_lease       11              7               141

Fixes: https://tracker.ceph.com/issues/43215
Signed-off-by: Xiubo Li <xiubli@redhat.com>
---
 fs/ceph/debugfs.c    | 32 ++++++++++++++++++++++++++++----
 fs/ceph/dir.c        | 18 ++++++++++++++++--
 fs/ceph/mds_client.c | 37 +++++++++++++++++++++++++++++++++++--
 fs/ceph/mds_client.h |  9 +++++++++
 fs/ceph/super.h      |  1 +
 5 files changed, 89 insertions(+), 8 deletions(-)

Comments

Jeff Layton Jan. 9, 2020, 1:52 p.m. UTC | #1
On Wed, 2020-01-08 at 05:41 -0500, xiubli@redhat.com wrote:
> From: Xiubo Li <xiubli@redhat.com>
> 
> For the dentry lease we will only count the hit/miss info triggered
> from the vfs calls, for the cases like request reply handling and
> perodically ceph_trim_dentries() we will ignore them.
> 
> Currently only the debugfs is support:
> 
> The output will be:
> 
> item          total           miss            hit
> -------------------------------------------------
> d_lease       11              7               141
> 
> Fixes: https://tracker.ceph.com/issues/43215
> Signed-off-by: Xiubo Li <xiubli@redhat.com>
> ---
>  fs/ceph/debugfs.c    | 32 ++++++++++++++++++++++++++++----
>  fs/ceph/dir.c        | 18 ++++++++++++++++--
>  fs/ceph/mds_client.c | 37 +++++++++++++++++++++++++++++++++++--
>  fs/ceph/mds_client.h |  9 +++++++++
>  fs/ceph/super.h      |  1 +
>  5 files changed, 89 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
> index fb7cabd98e7b..40a22da0214a 100644
> --- a/fs/ceph/debugfs.c
> +++ b/fs/ceph/debugfs.c
> @@ -124,6 +124,22 @@ static int mdsc_show(struct seq_file *s, void *p)
>  	return 0;
>  }
>  
> +static int metric_show(struct seq_file *s, void *p)
> +{
> +	struct ceph_fs_client *fsc = s->private;
> +	struct ceph_mds_client *mdsc = fsc->mdsc;
> +
> +	seq_printf(s, "item          total           miss            hit\n");
> +	seq_printf(s, "-------------------------------------------------\n");
> +
> +	seq_printf(s, "%-14s%-16lld%-16lld%lld\n", "d_lease",
> +		   atomic64_read(&mdsc->metric.total_dentries),
> +		   percpu_counter_sum(&mdsc->metric.d_lease_mis),
> +		   percpu_counter_sum(&mdsc->metric.d_lease_hit));
> +
> +	return 0;
> +}
> +
>  static int caps_show_cb(struct inode *inode, struct ceph_cap *cap, void *p)
>  {
>  	struct seq_file *s = p;
> @@ -220,6 +236,7 @@ static int mds_sessions_show(struct seq_file *s, void *ptr)
>  
>  CEPH_DEFINE_SHOW_FUNC(mdsmap_show)
>  CEPH_DEFINE_SHOW_FUNC(mdsc_show)
> +CEPH_DEFINE_SHOW_FUNC(metric_show)
>  CEPH_DEFINE_SHOW_FUNC(caps_show)
>  CEPH_DEFINE_SHOW_FUNC(mds_sessions_show)
>  
> @@ -255,6 +272,7 @@ void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)
>  	debugfs_remove(fsc->debugfs_mdsmap);
>  	debugfs_remove(fsc->debugfs_mds_sessions);
>  	debugfs_remove(fsc->debugfs_caps);
> +	debugfs_remove(fsc->debugfs_metric);
>  	debugfs_remove(fsc->debugfs_mdsc);
>  }
>  
> @@ -295,11 +313,17 @@ void ceph_fs_debugfs_init(struct ceph_fs_client *fsc)
>  						fsc,
>  						&mdsc_show_fops);
>  
> +	fsc->debugfs_metric = debugfs_create_file("metrics",
> +						  0400,
> +						  fsc->client->debugfs_dir,
> +						  fsc,
> +						  &metric_show_fops);
> +
>  	fsc->debugfs_caps = debugfs_create_file("caps",
> -						   0400,
> -						   fsc->client->debugfs_dir,
> -						   fsc,
> -						   &caps_show_fops);
> +						0400,
> +						fsc->client->debugfs_dir,
> +						fsc,
> +						&caps_show_fops);
>  }
>  
>  
> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> index d0cd0aba5843..382beb04bacb 100644
> --- a/fs/ceph/dir.c
> +++ b/fs/ceph/dir.c
> @@ -38,6 +38,8 @@ static int __dir_lease_try_check(const struct dentry *dentry);
>  static int ceph_d_init(struct dentry *dentry)
>  {
>  	struct ceph_dentry_info *di;
> +	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
> +	struct ceph_mds_client *mdsc = fsc->mdsc;
>  
>  	di = kmem_cache_zalloc(ceph_dentry_cachep, GFP_KERNEL);
>  	if (!di)
> @@ -48,6 +50,9 @@ static int ceph_d_init(struct dentry *dentry)
>  	di->time = jiffies;
>  	dentry->d_fsdata = di;
>  	INIT_LIST_HEAD(&di->lease_list);
> +
> +	atomic64_inc(&mdsc->metric.total_dentries);
> +
>  	return 0;
>  }
>  
> @@ -1551,6 +1556,7 @@ static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
>   */
>  static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
>  {
> +	struct ceph_mds_client *mdsc;
>  	int valid = 0;
>  	struct dentry *parent;
>  	struct inode *dir, *inode;
> @@ -1589,13 +1595,14 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
>  		}
>  	}
>  
> +	mdsc = ceph_sb_to_client(dir->i_sb)->mdsc;
>  	if (!valid) {
> -		struct ceph_mds_client *mdsc =
> -			ceph_sb_to_client(dir->i_sb)->mdsc;
>  		struct ceph_mds_request *req;
>  		int op, err;
>  		u32 mask;
>  
> +		percpu_counter_inc(&mdsc->metric.d_lease_mis);
> +
>  		if (flags & LOOKUP_RCU)
>  			return -ECHILD;
>  

So suppose we're doing an RCU walk, and call d_revalidate and the dentry
is invalid. We'll bump the counter here, but then return -ECHILD and the
kernel will do the d_revalidate all over again with refwalk, and we bump
the counter again.

Won't that end up double-counting the cache miss? Or is that intended
here?

> @@ -1630,6 +1637,8 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
>  			dout("d_revalidate %p lookup result=%d\n",
>  			     dentry, err);
>  		}
> +	} else {
> +		percpu_counter_inc(&mdsc->metric.d_lease_hit);
>  	}
>  
>  	dout("d_revalidate %p %s\n", dentry, valid ? "valid" : "invalid");
> @@ -1638,6 +1647,7 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
>  
>  	if (!(flags & LOOKUP_RCU))
>  		dput(parent);
> +
>  	return valid;
>  }
>  
> @@ -1672,9 +1682,13 @@ static int ceph_d_delete(const struct dentry *dentry)
>  static void ceph_d_release(struct dentry *dentry)
>  {
>  	struct ceph_dentry_info *di = ceph_dentry(dentry);
> +	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
> +	struct ceph_mds_client *mdsc = fsc->mdsc;
>  
>  	dout("d_release %p\n", dentry);
>  
> +	atomic64_dec(&mdsc->metric.total_dentries);
> +
>  	spin_lock(&dentry->d_lock);
>  	__dentry_lease_unlist(di);
>  	dentry->d_fsdata = NULL;
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index d379f489ab63..a976febf9647 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -4157,10 +4157,31 @@ static void delayed_work(struct work_struct *work)
>  	schedule_delayed(mdsc);
>  }
>  
> +static int ceph_mdsc_metric_init(struct ceph_client_metric *metric)
> +{
> +	int ret;
> +
> +	if (!metric)
> +		return -EINVAL;
> +
> +	atomic64_set(&metric->total_dentries, 0);
> +	ret = percpu_counter_init(&metric->d_lease_hit, 0, GFP_KERNEL);
> +	if (ret)
> +		return ret;
> +	ret = percpu_counter_init(&metric->d_lease_mis, 0, GFP_KERNEL);
> +	if (ret) {
> +		percpu_counter_destroy(&metric->d_lease_hit);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  int ceph_mdsc_init(struct ceph_fs_client *fsc)
>  
>  {
>  	struct ceph_mds_client *mdsc;
> +	int err;
>  
>  	mdsc = kzalloc(sizeof(struct ceph_mds_client), GFP_NOFS);
>  	if (!mdsc)
> @@ -4169,8 +4190,8 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
>  	mutex_init(&mdsc->mutex);
>  	mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
>  	if (!mdsc->mdsmap) {
> -		kfree(mdsc);
> -		return -ENOMEM;
> +		err = -ENOMEM;
> +		goto err_mdsc;
>  	}
>  
>  	fsc->mdsc = mdsc;
> @@ -4209,6 +4230,9 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
>  	init_waitqueue_head(&mdsc->cap_flushing_wq);
>  	INIT_WORK(&mdsc->cap_reclaim_work, ceph_cap_reclaim_work);
>  	atomic_set(&mdsc->cap_reclaim_pending, 0);
> +	err = ceph_mdsc_metric_init(&mdsc->metric);
> +	if (err)
> +		goto err_mdsmap;
>  
>  	spin_lock_init(&mdsc->dentry_list_lock);
>  	INIT_LIST_HEAD(&mdsc->dentry_leases);
> @@ -4227,6 +4251,12 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
>  	strscpy(mdsc->nodename, utsname()->nodename,
>  		sizeof(mdsc->nodename));
>  	return 0;
> +
> +err_mdsmap:
> +	kfree(mdsc->mdsmap);
> +err_mdsc:
> +	kfree(mdsc);
> +	return err;
>  }
>  
>  /*
> @@ -4484,6 +4514,9 @@ void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
>  
>  	ceph_mdsc_stop(mdsc);
>  
> +	percpu_counter_destroy(&mdsc->metric.d_lease_mis);
> +	percpu_counter_destroy(&mdsc->metric.d_lease_hit);
> +
>  	fsc->mdsc = NULL;
>  	kfree(mdsc);
>  	dout("mdsc_destroy %p done\n", mdsc);
> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> index c950f8f88f58..22186060bc37 100644
> --- a/fs/ceph/mds_client.h
> +++ b/fs/ceph/mds_client.h
> @@ -358,6 +358,13 @@ struct cap_wait {
>  	int			want;
>  };
>  
> +/* This is the global metrics */
> +struct ceph_client_metric {
> +	atomic64_t		total_dentries;
> +	struct percpu_counter	d_lease_hit;
> +	struct percpu_counter	d_lease_mis;
> +};
> +
>  /*
>   * mds client state
>   */
> @@ -446,6 +453,8 @@ struct ceph_mds_client {
>  	struct list_head  dentry_leases;     /* fifo list */
>  	struct list_head  dentry_dir_leases; /* lru list */
>  
> +	struct ceph_client_metric metric;
> +
>  	spinlock_t		snapid_map_lock;
>  	struct rb_root		snapid_map_tree;
>  	struct list_head	snapid_map_lru;
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index 3bf1a01cd536..40703588b889 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -123,6 +123,7 @@ struct ceph_fs_client {
>  	struct dentry *debugfs_congestion_kb;
>  	struct dentry *debugfs_bdi;
>  	struct dentry *debugfs_mdsc, *debugfs_mdsmap;
> +	struct dentry *debugfs_metric;
>  	struct dentry *debugfs_mds_sessions;
>  #endif
>
Xiubo Li Jan. 10, 2020, 2:41 a.m. UTC | #2
On 2020/1/9 21:52, Jeff Layton wrote:
> On Wed, 2020-01-08 at 05:41 -0500, xiubli@redhat.com wrote:
[...]
>> @@ -1589,13 +1595,14 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
>>   		}
>>   	}
>>   
>> +	mdsc = ceph_sb_to_client(dir->i_sb)->mdsc;
>>   	if (!valid) {
>> -		struct ceph_mds_client *mdsc =
>> -			ceph_sb_to_client(dir->i_sb)->mdsc;
>>   		struct ceph_mds_request *req;
>>   		int op, err;
>>   		u32 mask;
>>   
>> +		percpu_counter_inc(&mdsc->metric.d_lease_mis);
>> +
>>   		if (flags & LOOKUP_RCU)
>>   			return -ECHILD;
>>   
> So suppose we're doing an RCU walk, and call d_revalidate and the dentry
> is invalid. We'll bump the counter here, but then return -ECHILD and the
> kernel will do the d_revalidate all over again with refwalk, and we bump
> the counter again.
>
> Won't that end up double-counting the cache miss? Or is that intended
> here?

Yeah, we should count it once. Will fix it in the next version.

Thanks,

Patch
diff mbox series

diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index fb7cabd98e7b..40a22da0214a 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -124,6 +124,22 @@  static int mdsc_show(struct seq_file *s, void *p)
 	return 0;
 }
 
+static int metric_show(struct seq_file *s, void *p)
+{
+	struct ceph_fs_client *fsc = s->private;
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+
+	seq_printf(s, "item          total           miss            hit\n");
+	seq_printf(s, "-------------------------------------------------\n");
+
+	seq_printf(s, "%-14s%-16lld%-16lld%lld\n", "d_lease",
+		   atomic64_read(&mdsc->metric.total_dentries),
+		   percpu_counter_sum(&mdsc->metric.d_lease_mis),
+		   percpu_counter_sum(&mdsc->metric.d_lease_hit));
+
+	return 0;
+}
+
 static int caps_show_cb(struct inode *inode, struct ceph_cap *cap, void *p)
 {
 	struct seq_file *s = p;
@@ -220,6 +236,7 @@  static int mds_sessions_show(struct seq_file *s, void *ptr)
 
 CEPH_DEFINE_SHOW_FUNC(mdsmap_show)
 CEPH_DEFINE_SHOW_FUNC(mdsc_show)
+CEPH_DEFINE_SHOW_FUNC(metric_show)
 CEPH_DEFINE_SHOW_FUNC(caps_show)
 CEPH_DEFINE_SHOW_FUNC(mds_sessions_show)
 
@@ -255,6 +272,7 @@  void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)
 	debugfs_remove(fsc->debugfs_mdsmap);
 	debugfs_remove(fsc->debugfs_mds_sessions);
 	debugfs_remove(fsc->debugfs_caps);
+	debugfs_remove(fsc->debugfs_metric);
 	debugfs_remove(fsc->debugfs_mdsc);
 }
 
@@ -295,11 +313,17 @@  void ceph_fs_debugfs_init(struct ceph_fs_client *fsc)
 						fsc,
 						&mdsc_show_fops);
 
+	fsc->debugfs_metric = debugfs_create_file("metrics",
+						  0400,
+						  fsc->client->debugfs_dir,
+						  fsc,
+						  &metric_show_fops);
+
 	fsc->debugfs_caps = debugfs_create_file("caps",
-						   0400,
-						   fsc->client->debugfs_dir,
-						   fsc,
-						   &caps_show_fops);
+						0400,
+						fsc->client->debugfs_dir,
+						fsc,
+						&caps_show_fops);
 }
 
 
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index d0cd0aba5843..382beb04bacb 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -38,6 +38,8 @@  static int __dir_lease_try_check(const struct dentry *dentry);
 static int ceph_d_init(struct dentry *dentry)
 {
 	struct ceph_dentry_info *di;
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
 
 	di = kmem_cache_zalloc(ceph_dentry_cachep, GFP_KERNEL);
 	if (!di)
@@ -48,6 +50,9 @@  static int ceph_d_init(struct dentry *dentry)
 	di->time = jiffies;
 	dentry->d_fsdata = di;
 	INIT_LIST_HEAD(&di->lease_list);
+
+	atomic64_inc(&mdsc->metric.total_dentries);
+
 	return 0;
 }
 
@@ -1551,6 +1556,7 @@  static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
  */
 static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 {
+	struct ceph_mds_client *mdsc;
 	int valid = 0;
 	struct dentry *parent;
 	struct inode *dir, *inode;
@@ -1589,13 +1595,14 @@  static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 		}
 	}
 
+	mdsc = ceph_sb_to_client(dir->i_sb)->mdsc;
 	if (!valid) {
-		struct ceph_mds_client *mdsc =
-			ceph_sb_to_client(dir->i_sb)->mdsc;
 		struct ceph_mds_request *req;
 		int op, err;
 		u32 mask;
 
+		percpu_counter_inc(&mdsc->metric.d_lease_mis);
+
 		if (flags & LOOKUP_RCU)
 			return -ECHILD;
 
@@ -1630,6 +1637,8 @@  static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 			dout("d_revalidate %p lookup result=%d\n",
 			     dentry, err);
 		}
+	} else {
+		percpu_counter_inc(&mdsc->metric.d_lease_hit);
 	}
 
 	dout("d_revalidate %p %s\n", dentry, valid ? "valid" : "invalid");
@@ -1638,6 +1647,7 @@  static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 
 	if (!(flags & LOOKUP_RCU))
 		dput(parent);
+
 	return valid;
 }
 
@@ -1672,9 +1682,13 @@  static int ceph_d_delete(const struct dentry *dentry)
 static void ceph_d_release(struct dentry *dentry)
 {
 	struct ceph_dentry_info *di = ceph_dentry(dentry);
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
 
 	dout("d_release %p\n", dentry);
 
+	atomic64_dec(&mdsc->metric.total_dentries);
+
 	spin_lock(&dentry->d_lock);
 	__dentry_lease_unlist(di);
 	dentry->d_fsdata = NULL;
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index d379f489ab63..a976febf9647 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4157,10 +4157,31 @@  static void delayed_work(struct work_struct *work)
 	schedule_delayed(mdsc);
 }
 
+static int ceph_mdsc_metric_init(struct ceph_client_metric *metric)
+{
+	int ret;
+
+	if (!metric)
+		return -EINVAL;
+
+	atomic64_set(&metric->total_dentries, 0);
+	ret = percpu_counter_init(&metric->d_lease_hit, 0, GFP_KERNEL);
+	if (ret)
+		return ret;
+	ret = percpu_counter_init(&metric->d_lease_mis, 0, GFP_KERNEL);
+	if (ret) {
+		percpu_counter_destroy(&metric->d_lease_hit);
+		return ret;
+	}
+
+	return 0;
+}
+
 int ceph_mdsc_init(struct ceph_fs_client *fsc)
 
 {
 	struct ceph_mds_client *mdsc;
+	int err;
 
 	mdsc = kzalloc(sizeof(struct ceph_mds_client), GFP_NOFS);
 	if (!mdsc)
@@ -4169,8 +4190,8 @@  int ceph_mdsc_init(struct ceph_fs_client *fsc)
 	mutex_init(&mdsc->mutex);
 	mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
 	if (!mdsc->mdsmap) {
-		kfree(mdsc);
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto err_mdsc;
 	}
 
 	fsc->mdsc = mdsc;
@@ -4209,6 +4230,9 @@  int ceph_mdsc_init(struct ceph_fs_client *fsc)
 	init_waitqueue_head(&mdsc->cap_flushing_wq);
 	INIT_WORK(&mdsc->cap_reclaim_work, ceph_cap_reclaim_work);
 	atomic_set(&mdsc->cap_reclaim_pending, 0);
+	err = ceph_mdsc_metric_init(&mdsc->metric);
+	if (err)
+		goto err_mdsmap;
 
 	spin_lock_init(&mdsc->dentry_list_lock);
 	INIT_LIST_HEAD(&mdsc->dentry_leases);
@@ -4227,6 +4251,12 @@  int ceph_mdsc_init(struct ceph_fs_client *fsc)
 	strscpy(mdsc->nodename, utsname()->nodename,
 		sizeof(mdsc->nodename));
 	return 0;
+
+err_mdsmap:
+	kfree(mdsc->mdsmap);
+err_mdsc:
+	kfree(mdsc);
+	return err;
 }
 
 /*
@@ -4484,6 +4514,9 @@  void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
 
 	ceph_mdsc_stop(mdsc);
 
+	percpu_counter_destroy(&mdsc->metric.d_lease_mis);
+	percpu_counter_destroy(&mdsc->metric.d_lease_hit);
+
 	fsc->mdsc = NULL;
 	kfree(mdsc);
 	dout("mdsc_destroy %p done\n", mdsc);
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index c950f8f88f58..22186060bc37 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -358,6 +358,13 @@  struct cap_wait {
 	int			want;
 };
 
+/* This is the global metrics */
+struct ceph_client_metric {
+	atomic64_t		total_dentries;
+	struct percpu_counter	d_lease_hit;
+	struct percpu_counter	d_lease_mis;
+};
+
 /*
  * mds client state
  */
@@ -446,6 +453,8 @@  struct ceph_mds_client {
 	struct list_head  dentry_leases;     /* fifo list */
 	struct list_head  dentry_dir_leases; /* lru list */
 
+	struct ceph_client_metric metric;
+
 	spinlock_t		snapid_map_lock;
 	struct rb_root		snapid_map_tree;
 	struct list_head	snapid_map_lru;
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 3bf1a01cd536..40703588b889 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -123,6 +123,7 @@  struct ceph_fs_client {
 	struct dentry *debugfs_congestion_kb;
 	struct dentry *debugfs_bdi;
 	struct dentry *debugfs_mdsc, *debugfs_mdsmap;
+	struct dentry *debugfs_metric;
 	struct dentry *debugfs_mds_sessions;
 #endif