nfsd: report per-export stats

Collect some nfsd stats per export in addition to the global stats.

A new nfsdfs export_stats file is created.  It uses the same ops as the
exports file to iterate the export entries and we use the file's name to
determine the reported info per export.  For example:

 $ cat /proc/fs/nfsd/export_stats
 # Version 1.1
 # Path Client Start-time
 #	Stats
 /test	localhost	92
	fh_stale: 0
	io_read: 9
	io_write: 1

Every export entry reports the start time when stats collection
started, so stats collecting scripts can know if stats where reset
between samples.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

1 files changed, 60 insertions, 8 deletions

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 81e7bb12aca6..7c863f2c21e0 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -331,12 +331,29 @@ static void nfsd4_fslocs_free(struct nfsd4_fs_locations *fsloc)
 	fsloc->locations = NULL;
 }
 
+static int export_stats_init(struct export_stats *stats)
+{
+	stats->start_time = ktime_get_seconds();
+	return nfsd_percpu_counters_init(stats->counter, EXP_STATS_COUNTERS_NUM);
+}
+
+static void export_stats_reset(struct export_stats *stats)
+{
+	nfsd_percpu_counters_reset(stats->counter, EXP_STATS_COUNTERS_NUM);
+}
+
+static void export_stats_destroy(struct export_stats *stats)
+{
+	nfsd_percpu_counters_destroy(stats->counter, EXP_STATS_COUNTERS_NUM);
+}
+
 static void svc_export_put(struct kref *ref)
 {
 	struct svc_export *exp = container_of(ref, struct svc_export, h.ref);
 	path_put(&exp->ex_path);
 	auth_domain_put(exp->ex_client);
 	nfsd4_fslocs_free(&exp->ex_fslocs);
+	export_stats_destroy(&exp->ex_stats);
 	kfree(exp->ex_uuid);
 	kfree_rcu(exp, ex_rcu);
 }
@@ -692,22 +709,47 @@ static void exp_flags(struct seq_file *m, int flag, int fsid,
 		kuid_t anonu, kgid_t anong, struct nfsd4_fs_locations *fslocs);
 static void show_secinfo(struct seq_file *m, struct svc_export *exp);
 
+static int is_export_stats_file(struct seq_file *m)
+{
+	/*
+	 * The export_stats file uses the same ops as the exports file.
+	 * We use the file's name to determine the reported info per export.
+	 * There is no rename in nsfdfs, so d_name.name is stable.
+	 */
+	return !strcmp(m->file->f_path.dentry->d_name.name, "export_stats");
+}
+
 static int svc_export_show(struct seq_file *m,
 			   struct cache_detail *cd,
 			   struct cache_head *h)
 {
-	struct svc_export *exp ;
+	struct svc_export *exp;
+	bool export_stats = is_export_stats_file(m);
 
-	if (h ==NULL) {
-		seq_puts(m, "#path domain(flags)\n");
+	if (h == NULL) {
+		if (export_stats)
+			seq_puts(m, "#path domain start-time\n#\tstats\n");
+		else
+			seq_puts(m, "#path domain(flags)\n");
 		return 0;
 	}
 	exp = container_of(h, struct svc_export, h);
 	seq_path(m, &exp->ex_path, " \t\n\\");
 	seq_putc(m, '\t');
 	seq_escape(m, exp->ex_client->name, " \t\n\\");
+	if (export_stats) {
+		seq_printf(m, "\t%lld\n", exp->ex_stats.start_time);
+		seq_printf(m, "\tfh_stale: %lld\n",
+			   percpu_counter_sum_positive(&exp->ex_stats.counter[EXP_STATS_FH_STALE]));
+		seq_printf(m, "\tio_read: %lld\n",
+			   percpu_counter_sum_positive(&exp->ex_stats.counter[EXP_STATS_IO_READ]));
+		seq_printf(m, "\tio_write: %lld\n",
+			   percpu_counter_sum_positive(&exp->ex_stats.counter[EXP_STATS_IO_WRITE]));
+		seq_putc(m, '\n');
+		return 0;
+	}
 	seq_putc(m, '(');
-	if (test_bit(CACHE_VALID, &h->flags) && 
+	if (test_bit(CACHE_VALID, &h->flags) &&
 	    !test_bit(CACHE_NEGATIVE, &h->flags)) {
 		exp_flags(m, exp->ex_flags, exp->ex_fsid,
 			  exp->ex_anon_uid, exp->ex_anon_gid, &exp->ex_fslocs);
@@ -748,6 +790,7 @@ static void svc_export_init(struct cache_head *cnew, struct cache_head *citem)
 	new->ex_layout_types = 0;
 	new->ex_uuid = NULL;
 	new->cd = item->cd;
+	export_stats_reset(&new->ex_stats);
 }
 
 static void export_update(struct cache_head *cnew, struct cache_head *citem)
@@ -780,10 +823,15 @@ static void export_update(struct cache_head *cnew, struct cache_head *citem)
 static struct cache_head *svc_export_alloc(void)
 {
 	struct svc_export *i = kmalloc(sizeof(*i), GFP_KERNEL);
-	if (i)
-		return &i->h;
-	else
+	if (!i)
+		return NULL;
+
+	if (export_stats_init(&i->ex_stats)) {
+		kfree(i);
 		return NULL;
+	}
+
+	return &i->h;
 }
 
 static const struct cache_detail svc_export_cache_template = {
@@ -1245,10 +1293,14 @@ static int e_show(struct seq_file *m, void *p)
 	struct cache_head *cp = p;
 	struct svc_export *exp = container_of(cp, struct svc_export, h);
 	struct cache_detail *cd = m->private;
+	bool export_stats = is_export_stats_file(m);
 
 	if (p == SEQ_START_TOKEN) {
 		seq_puts(m, "# Version 1.1\n");
-		seq_puts(m, "# Path Client(Flags) # IPs\n");
+		if (export_stats)
+			seq_puts(m, "# Path Client Start-time\n#\tStats\n");
+		else
+			seq_puts(m, "# Path Client(Flags) # IPs\n");
 		return 0;
 	}